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Scanned  from  the  collections  of 
The  Library  of  Congress 


AUDIO-VISUAL  CONSERVATION 

*"■    ■*-       ML 


atThe  LIBRARY  of  CONGRESS  'jjjjj'j  fiffe/     D   T|Br  Iff  I 


Packard  Campus 

for  Audio  Visual  Conservation 

www.loc.gov/avconservation 

Motion  Picture  and  Television  Reading  Room 
www.loc.gov/rr/mopic 

Recorded  Sound  Reference  Center 
www.loc.gov/rr/record 


Blueprint  JiweQtion  Every  Month 


MEET  YOUR  B 


FAVORITES 


Super-Zenith  VII— 

the  ideal  radio  set 

for  the  fine  home 


They  Cost  More 

But  They  Do  More 


Super- 
Zenith  X 


Each  station  comes  in  at  the 
same  point  on  the  dial,  always 

You  don't  need  to  be  a  "radio  engineer,"  and  you  don't  need  to 
have  three  hands,  to  operate  the  new  Super-Zenith.  Tuning  is 
controlled  by  two  dials  only — so  perfectly  adjusted  that  each 
station  comes  in  always  at  the  same  dial  settings.  It  never 
varies.  Powerful  locals  may  be  on  full  blast,  yet,  if  you  like, 
you  can  tune  them  out  completely,  choose  the  distant  station. 

Those  who  know  and  appreciate  truthful  tone  reproduction  find 
in  the  new  Super-Zenith  an  unfailing  source  of  delight.  Their 
pleasure  is  all  the  greater  from  the  fact  that  even  when  silent 
the  Super-Zenith  lends  to  its  surroundings  charm  and  distinction. 

Write  to  us  for  the  name  of  the  nearest  dealer  from  whom  you 
can  obtain  a  demonstration  of  this  outstanding  marvel  of  the 
radio  world. 
Dealers  and  Jobbers:  Write  or  wire  for  our  exclusive  territorial  franchise 

ZENITH  RADIO  CORPORATION 

Executive  Offices:    332  South  Michigan  Ave.,  Chicago 

ZENITH— the  exclusive  choice  of  MacMUlan  for  his  North  Pole  Expedition 
— Holder  of  the  Berengaria  Record 


A 


d— Zenith       ^\ 
enlevement,    ^l 


V 


THE  complete  Zenith  line  in- 
cludes seven  models,  ranging 
in  price  from  $95  to  $550. 

With  either  Zenith  3R  or  Zenith 
4R,  satisfactory  reception  over 
distances  of  2,000  to  3,000  miles 
is  readily  accomplished,  using 
any  ordinary  loud  speaker. 
Models  3Rand4R  licensed  under 
ArmstrongU.S.Pat.No.l,  113,149. 

The  new  Super-Zenith  is  a  six- 
tube  set  with  a  new,  unique, 
and  really  different  patented 
circuit,  controlled  exclusively  by 
the  Zenith  Radio  Corporation. 
It  is  NOT  regenerative. 


SUPER-ZENITH  VII  — Six  tubes-2  stages  tuned 
frequency  amplification — detector  and  3  stages  audio 
frequency  amplification.  Installed  in  a  beautifully 
finished  cabinet  of  solid  mahogany  —  44's  inches 
long,  16?i  inches  wide,  10s4  inches  high.  Compart- 
ments at  either  end  for  dry  batteries.  Price  A^^/\ 
(exclusive  of  tubes  and  batteries)     ....  JpZ  JV 


impossible  -with  single-unit  speakers.  2nd- 

Battery  Eliminator,  distinctly  a  Zenith  achievement. 

Requires  no  A  or  B  batteries  <bCC/"\ 

Price  (exclusive  of  tubes) ^>35v 

Price  (without  battery  eliminator)     .     .    ...    $450 
All  Prices  F.  O.  B.  Factory. 


SUPER-ZENITH  VIII  -  Same  as 
type.  Price  (exclusive  of  tubes 
teries)      ...    


SUPER-ZENITH  IX— Console  model  with  addi- 
tional compartments  containing  built-in  Zenith  loud 
speaker  and  generous  storage  battery  space.  (t^CA 
Price  (exclusive  of  tubes  and  batteries)    .    ,TJ-'W 


vii  except— console    i  Zenith  Radio  Corporation 

b3t"  $250  Dept.lC 

I  332  South  Michigan  Avenue,  Chicago,  111. 


Gentlemen:  Please  send  me  illustrated  literature 
giving  full  details  of  the  Super-Zenith. 


ft — Contains  two  new  features 
ceivers.  1st— Built  in,  patented, 
»-Loud  Speakers  (harmonically 
speakers  and  horns),  designed  to 
h  and  low  pitch  tones  otherwise 


J 


i  and  Appfoved  by  RADIO  AGE     * 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


Tune  In  on  a  Real  Job 

and  Get  the  Pay  of  a  Specialist 

^isffeeflookWMShowfou 
ffow  to  "Earn  $1500  to  WOOQ  " 
karly  as  a  %idio  Expert » 


THE  man  who  would  be  a  success  in 
business  today  must  be  a  specialist. 
The  market  is  already  crowded  with 
clerks,  stenographers,  accountants  and 
detail  men  of  every  description.  And  as 
the  number  of  applicants  increases,  the 
pay  and  opportunities  diminish.  Not 
that  these  men  are  unnecessary,  for  their 
work  is  important  and  essential.  But 
the  competition  has  always  been  keen 
in  general  work  of  this  kind  and  it  is 
bound  to  increase  in  proportion  to  the 
number  of  good  men  available. 

Radio  Needs  Trained  Men 

There  is  perhaps  no  other  field  today 
where  specialists  are  needed  more  than 
in  Radio.  Trained  men  are  required  in 
every  branch  of  this  fascinating,  profit- 
able profession.  And  the  opportunities 
are  great — almost  without  limit!  Radio 
has  swept  across  the  face  of  the  whole 
earth  with  a  speed  as  surprising  as  it 
was  sudden.  Almost  overnight  it 
jumped  into  the  front  rank  of  the 
world's  leading  industries.  Yet  it  is 
here  to   stay — and  grow.  For  that 

reason  Radio  needs  good  men.  It  is 
ready  to  treat  them  right  and  pay  them 
well.  And  for  the  men  who  "get  in" 
NOW,  the  best  is  none  too  good. 


K| 


Pay  Increases 
Over  $100  a  Month 

I  am  averaging  anywhere  from 
S75  to  S150  a  month  more  than  I 
was  making  before  enrolling  with 
you.  I  would  not  consider  510,000 
9  too  much  for  the  course. 
1L  (Signed)      A.  N.  Lone, 

■/  120  N.  Main  Street, 

"  Greensburg,  Pa. 


Doubles  Salary 

I  can  very  easily  make  double 
the  amount  of  money  now  than  be- 
fore I  enrolled  with  you.  Your 
course  has  benefited  me  approxi- 
mately S3000  over  and  above  what 
I   would   have  earned   had   I   not 

T.  "Winder, 

731  Bedford  Ave., 

Grand  Junction,  Colo. 


From  $15.00  to  $80.00  aWeek 

Before  I  enrolled  with  you  I 
was  making  SI  5  a  week  on  a  farm. 
Now  I  earu  from  S2080  to  S4420 
a  year,  and  the  work  is  a  hundred 


times   easier  than 

before.     Since 

graduating  a  little 

over  a  year  ago, 

I  have  earned  aim 

ost  S4000  and  I 

believe  the  cours* 

will  be  worth 

at  least  SI 00,000 

to  me. 

(Signed)     Ge 

■>.  A.  Adams. 

Route  1,  Box  10, 

Tamaq.ua,   Pa. 

Get  Into  This 
Big  Paying 
Profession 

Consider  for  a  mo- 
ment the  possibilities 
of  Radio.  The  shores 
of  every  continent 
are  dotted  with  trans- 
mitting and  receiving 
stations.  Practically 
every  vessel  is  now 
equipped  for  commu- 
nication with  land 
and  other  ships.  Hotels,  railroad  ter- 
minals, public  buildings  and  Govern- 
ment stations  are  flashing  their  business 
messages  'cross  cities,  rivers,  mountains 
and  seas.  At  night,  millions  of  men, 
women  and  children  are  "listening  in" 
to  music,  speeches,  news,  important 
events  and  business  reports,  broadcast 
for  their  amusement  and  education. 
Factories,  stores,  banks,  laboratories, 
business  houses  and  newspaper  offices 
are  employing  Radio  experts  in  every 
branch  of  the  profession.  Yet  the 
demand  for  good  men  is  far  greater 
than  the  supply.  If  YOU  are  sick  of 
plugging  along  in  the  daily  grind  of 
monotonous  office  routine — held  down 
by  the  thousands  of  men  who  are  doing 
the  same  work  as  you — get  out  of  the 
rut  into  this  big  paying  profession. 

You  Can  Qualify  at  Home 
Easily  and  Quickly 

On  land  and  sea,  the  news  of  the 
world's  progress  is  flowing  under  the 
skilled  fingers  of  Certified  "Radio- 
tricians"— men  who  are  well-paid,  hon- 
ored and  respected  for  their  specialized 
knowledge  and  important  work.  A  short 
course  of  training  at  home  for  the  enjoy- 
able work  of  Radio,  will  quickly  enable 
you  to  be  independent,  to  travel  and  see 
the  world  if  you  wish,  or  establish 
yourself  in  a  permanent  position  in 
your  own  town.  Radio  will  take  you 
out  of  the  rut  of  a  bare  existence,  into 
the  enviable  standing  of  a  specialist — - 
with  unlimited  opportunities  for  honor, 
power,  wealth  and  satisfaction.  It  will 
make  you  a  doer  of  real  things,  a  vital 
force  in  the  world  and  an  important 
factor  in  your  own  community.  Start  to 
train  NOW  for  a  Radio  position,  while 
the  profession  is  growing.  You  can  start 
TODAY — in  your  spare  hours  at  home. 

The  National  Radio  Institute  is  train- 


ing men,  in  their  spare  hours  at  home, 
for  every  important  branch  of  the  big 
Radio  industry.  To  any  man  who  is 
eager  to  better  his  condition  and  make 
a  place  for  himself  in  this  fascinating 
and  profitable  profession,  we  will  gladly 
send  a  copy  of  this  timely,  helpful, 
book — absolutely  free.  It  is  called 
"Rich  Rewards  in  Radio"  and  it  will 
open  up  a  chain  of  opportunities  that 
you  will  do  well  to  carefully  consider. 

You  assume  no  obligation  whatever  in 
sending  for  this  interesting,  helpful 
book.  It  is  yours  for  the  asking — 
FREE.  For  that  reason  you  can  hardly 
afford  to  miss  it.  Ask  for  a  copy  today 
and  learn  the  tremendous  opportunities 
that  are  open  in  Radio,  how  we  are 
preparing  men  at  home  to  take  ad- 
vantage of  these  opportunities,  and 
how  we  aid  them  in  securing  the  kind 
of  positions  that  lead  to  independence 
and  success,  "Tune  in"  on  a  real  job — 
mail  the  coupon  for  this  Free  Book 
today — and  then  "stand  by"  until  it 
arrives  by  return  mail.  It  will  PAY 
you!  National  Radio  Institute,  Dept. 
53CB,  Washington,  D.  C. 

This  WillBring  It_ 

t         NATIONAL  RADIO  INSTITUTE, 
Dept.  53CB,  Washington,  D.  C. 

{Without  any  obligation  on  my  part,  please 
send  me  a  FREE  copy  of  your  book,  "Rich 
I  Rewards  in  Radio."     Also  tell  me  how  your 

Free  Employment  Service  will  help  me  secure 
a  position,  and  send  me  details  of  your  special 
I         short-time  offer. 

1         Name. 


Street 


City 


v_iiy ™ .- ouiie 


*     Tested  and  Approved  by  RADIO  AGE     ¥ 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITHWHICH  IS  COMBINED  RADIO  TOPICS 


Volume  4 


January,  1925 


Number  1 


CONTENTS 

Radiotorials 4 

First  Super  Stations  Licensed 7 

By  Robeit  D.  Heinl 

Attaining  Results  with  Radio  Frequency 9 

By  Armstrong  Perry 

A  Reflexed  Four-Tube  Neutrodyne 11 

By  H.  Frank  Hopkins 

Headsets — Their  Care  and  Operation 14 

By  Roscoe  Bundy 

A  Six-Tube  Super-Heterodyne 15 

By  Paul  Green 

Getting  Started  in  Radio — Beginners'  Section 18 

By  Edmund  H.  Eitel 

Tuning  in  with  the  French  Radio  Fan 20 

By  C.  R.  Bluzat 

An  Efficient  Portable  Set 21 

By  Brainard  Foote 

How  to  Make  a  Station  Finder 23 

By  Felix  Anderson 

Adding  Two  Stages  to  the  Modified  Reinartz ....26 

By  Frank  D.  Pearne 
"What  the  Broadcasters' are  Doing" — Studio-Land 
Features  for  the  Listener 28-40 

RADIO  AGE  BLUEPRINT  SECTION 

I.  The    Tuned    Impedance    Reflex    with    Two 
Stages 41 

II.  A  Tuned  Plate  Regenerative  Set 43 

By  John  B.  Rathbun 

Pickups  and  Hookups  by  Our  Readers 49 

Corrected  List  of  Broadcasting  Stations... 74 


Radio  Age  is  published  monthly  by  RADIO  AGE,   Inc. 
Member:     Audit  Bureau  of  Circulations. 


Executive,  Editorial  and  Advertising  Offices 
500  Tsr.  Dearbarn  Street,  Chicago,  111. 
Publication  Office,   Mount   Morris,  111. 

Frederick  A.  Smith,  Editor 
Russell  H.  Hopkins,  Associate  Editor 
Frank  D.  Pearne,  Technical  Editor 
Louis  L.  Levy,  Circulation  Manager 
M.  B.  Smith,  Business  Manager 

Advertising  Director 
HARRY  A.  ACKERBURG 


Eastern  Representative 
DAVIDSON  &  HEVEY,  17  West  42nd  St.,  New  York  City 

Pacific  Coast  Representative 
BENJAMIN  LEVEN,  582  Market  St.,  San  Francisco. 

Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 

preceding  date  of  issue 

Issued  monthly.  Vol.  4,  No.  1.  Subscription  price.  $2.50  a  year. 

Application  madefor  transfer  of  second  class  entry  from  the  post  office  at  Chicago, 

Illinois,  to  the  post  office  at  Mount  Morris,  Illinois 

Covuriqht.  1925.  by  RADIO  AGE,  Ivo. 


A  Chat  With 
the  Editor 

MR.  MANTON  DAVIS,  of 
the  Radio  Corporation  of 
America,  diverts  us  with 
a  letter  in  which  he  expresses  the 
suspicion  (baseless)  that  adver- 
tisers have  been  led  to  believe 
they  were  advertising  in  WIRE- 
LESS AGE,  when,  as  a  matter  of 
fact,  they  were  dealing  with 
RADIO  AGE.  Mr.  Davis  even 
threatens  to  call  out  the  agile 
R.  C.  A.  legal  department  and  cut 
our  heads  off. 

RADIO  AGE  and  WIRELESS 
AGE  are  two  separate  and  dis- 
tinct publications,  the  former  pub- 
lished in  Chicago  and  the  latter 
in  New  York.  We  do  not  make  this 
statement  because  we  think  an 
announcement  necessary  to  avert 
confusion  of  names  so  different  as 
these.  We  make  this  extremely 
obvious  distinction  because  we  do 
not  want  Mr.  Davis  to  think  that 
there  is  anything  in  the  adver- 
tising or  editorial  departments  of 
WIRELESS  AGE  that  RADIO 
AGE  wants,  much  less  would 
employ  sharp   practice  to  obtain. 

Radio  Corporation  of  America 
controls  WIRELESS  AGE.  It 
is  published  by  Wireless  Press, 
Inc.,  of  New  York.  RADIO 
AGE  is  owned  by  RADIO  AGE, 
Inc.,  of  which  the  undersigned  is 
President.  RADIO  AGE  is  not 
interested  directly  or  indirectly 
in  the  manufacture  or  sale  of  any 
radio  product  and  is  serving  as 
officiai  organ  for  nobody. 

The  writer  has  been  a  newspaper 
editor  for  a  quarter  of  a  century. 
He  was  war  correspondent  at  the 
French  front  for  the  Chicago 
Tribune.  He  was  special  corres- 
pondent in  Russia,  China  and 
Japan  for  the  same  newspaper  for 
two  years  after  the  war.  He  is 
now  editor  of  a  newspaper  radio 
section,  which  on  one  day  of  each 
week,  has  the  largest  radio  circu- 
lation in  the  world.  Also  he  is 
editor  and  chief  stockholder  of 
RADIO  AGE. 

Most  earnestly  he  hopes  that 
the  radio  public  will  not  make 
the  error  of  thinking  this  magazine 
has  any  association  with  the  peri- 
odical controlled  by  our  friend 
with  the  agile  legal  department. 

Editor  of  RADIO  AGE. 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


U^IIUjf^^f^X^^TjT^^^tJl^^WL^'iP^1 


■I  t»Ji zZ  *&&tjrJ)*i 


1511=1 


No.  766 
22y2-volt 

large 

horizontal 

Price 

$2.00 


■K 


mm 


t& t 


Vi> 


*  Cut  your 
operating  cost 

Thirty  years'  experience  in  the  manufacture 
of  dry  batteries  has  enabled  us  within  the 
past  two  years  to  steadily  and  greatly  improve 
dry  "B"  Battery  quality.  Eveready  "B" 
Batteries  are  now  from  two  to  three  times 
better  than  ever  before. 

Eveready  "B"  Batteries  will  long  outlast 
any  others,  and  are  the  most  economical  and 
dependable  source  of  plate  current.  These 
are  strong  statements,  but  they  have  been 
proved  by  tests  in  our  own  and  in  independent 
laboratories.  Check  them  for  yourself  on 
your  own  radio  set.  Get  Eveready  "B" 
Batteries. 

There  is  an  Eveready  Radio  Battery  for 
every  radio  use. 

Manufactured  and  guaranteed  by 

NATIONAL  CARBON   COMPANY,  Inc. 

Headquarters  for  Radio  Battery  Information 
New  York  San  Francisco 

Canadian  National   Carbon  Co.,   Limited,    Toronto,    Ontario 

EVEREADY 

Radio  Batteries 

— they  last  longer 


■ 


*     Tested  and  Approved  by  RADIO  AGE     V 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


Right  Here's  Where  We  Call  the  Bluff  of  a  $33,000,000  Radio  Crowd 


RADIO  Corporation  of  America  has  gone  into  the 
United  States  Patent  Office  and  filed  formal 
objection  to  registration  of  the  title,  RADIO 
AGE,  which  title  has  been  used  and  owned  by  the 
publishers  of  this  magazine  since  the  spring  of  1922. 
The  Radio  Corporation,  with  fine  insight  into  delicate 
legal  and  business  discriminations,  alleges  that  the 
title,  RADIO  AGE,  is  an  infringement  on  the  title  of 
"WIRELESS  AGE,"  a  publication  which  Radio 
Corporation  controls. 

This  initial  step  toward  trying  to  grab  the  name  of 
RADIO  AGE  and  give  the  name  to  its  own  organ  was 
preceded  by  threats  made  to  the  publishers  of  this 
magazine.  We  were  warned  that  if  we  did  not  sur- 
render the  name  of  our  magazine,  a  name  in  which  we 
have  generously  invested  labor  and  money,  Radio 
Corporation  would  turn  loose  its  legal  department  on 
us.  That  means  a  threat  of  bringing  us  into  federal 
court.  On  the  side  of  Radio  Corporation  would  be 
almost  unlimited  millions,  tremendous  influence  in 
quarters  where  "pull"  is  most  useful,  and  an  abso- 
lutely false  presumption  of  law  and  facts. 

Radio  Corporation  knows,  and  its  legal  department 
knows,  that  it  has  no  shadow  of  a  right  to  act  on  such 
a  violent  hypothesis  that  RADIO  AGE  as  a  name 
infringes  on  "Wireless  Age."  Lawyers  know  it;  the 
publishers  of  RADIO  AGE  know  it,  and  before  we  have 
finished  the  radio  public  is  going  to  know  it. 

If  we  were  in  the  position  before  the  American  people 
that  Radio  Corporation  occupies,  we  would  not  have 
taken  this  action  in  the  Patent  Office.  If  we  had  been 
the  Radio  Corporation,  we  would  not  have  sent  our 
agents  to  Washington  to  try  to  wrest  away  a  magazine 
title  from  its  rightful  owners,  but  we  would  have 
sent  them  to  Washington  to  meet  the  charges  that 
have  been  filed  there  by  the  Federal  Trade  Com- 
mission, a  bureau  of  the  United  States  government. 
We  would  have  been  devoting  all  of  our  effort  and  our 
appropriation  for  legal  talent  to  the  effort  of  disproving 
the  charge  that  we  were  a  trust  and  that  we  were  re- 
straining competition,  thus  working  a  hardship  upon 
twenty  millions  of  radio  fans. 

We  do  not  know  whether  or  not  a  radio  trust  exists, 
but  if  there  is  such  a  lawless  combination  in  restraint 
of  radio  commerce,  the  fans  who  are  spending  $350,000,- 
000  for  radio  merchandise  this  year  should,  and  prob- 
ably will,  find  a  way  to  express  their  opinion  of  it. 

Or,  if  we  had  been  Radio  Corporation,  instead  of 
reaching  out  into  the  Middle  West  to  strong-arm  a 
magazine  that  has  been  persistent  and  vigorous  in  up- 
building interest  in  radio,  we  would  have  sent  our 
agents  to  Richmond  Hill,  N.  Y.  We  would  have 
looked  up  Al  Grebe  out  there  at  his  big  new  broadcast- 
ing station  and  we  would  have  told  Al  that  we  were 
heartily  ashamed  that  the  Radio  Corporation  had 
brought  a  suit  against  him;  a  suit  so  devoid  of  legal 
justification  that  it  was  thrown  out  of  court  before 
proceedings  were  fairly  started. 

Or  if  we  had  been  in  Radio  Corporation's  place,  we 
would  have  called  together  sixty  independent  radio 
manufacturers  of  the  United  States  and  would  have 
given  those  independent  manufacturers  an  explana- 


tion of  Radio  Corporation's  great  good  fortune  in 
having  through  one  of  its  subsidiary  companies,  been 
privileged  to  manufacture  receiving  sets  under  license 
granted  by  the  government  while  the  sixty  independent 
manufacturers  could  not  obtain  a  similar  privilege. 
We  would  have  explained  to  the  sixty  independent 
manufacturers  and  to  the  American  public  how  it 
happened  that  it  required  eighteen  months  for  the 
independent  manufacturers  to  obtain  a  ruling  that 
they  were  entitled  to  the  same  advantages  from  the 
confiscated  German  patents  as  was  Radio  Corporation. 

We  would  have  sent  our  agents  down  to  Elgin, 
Illinois,  and  told  Charlie  Erbstein  that  he  could  have 
the  broadcasting  equipment  he  publicly  declares  the 
"Four  Horsemen"  refuse  to  sell  him  because  he  is 
against  radio  monopoly,  either  in  manufacturing, 
selling    or    broadcasting. 

RADIO  AGE  is  against  monopoly  also.  With 
deepest  respect  for  the  law  and  with  profound  faith  in 
the  fairness  of  the  people's  verdict  in  any  issue  where 
the  public  is  fully  informed  of  the  facts,  we  are  going 
to  do  our  best  to  maintain  what  the  constitution 
guaranteed  us — a  free  press. 

It  is  a  worthy  saying  that  truth  in  promotion  implies 
honesty  in  manufacture.  It  is  obvious  that  a  corpora- 
tion that  is  hopeful  of  building  up  good  will  for  itself 
and  its  product  by  threatening  continuously  to  turn 
loose  its  high-priced  lawyers  on  manufacturer,  dealer, 
editor  and  publisher,  is  afflicted  with  aggravated 
optimism. 

It  is  possible  that  Radio  Corporation  may  be  suc- 
cessful in  making  off  with  the  name  of  this  magazine. 
Even  so,  it  would  not  be  a  vital  blow.  A  rose  by  any 
other  name  would  smell  as  sweet.  It  is  possible  that 
almost  a  quarter  of  a  million  readers  would  still  read 
this  magazine  if  it  were  called  RADIO — Something 
else.  And  we  are  not  so  sure  that  manufacturers  of 
radio  equipment  would  not  still  favor  us  with  their 
advertising.  We  even  harbor  the  thought  that  we 
might  have  more  readers  and  more  advertising  after 
the  facts  become  known.  Readers  and  advertisers  are 
like    that    sometimes. 

The  Owner-Editor  of  RADIO  AGE  was  a  newspaper 
correspondent  at  the  front  with  the  American  Army 
in  France.  He  was  the  first  American  to  reach  Berlin 
after  the  Armistice  was  signed.  He  was  in  the  midst 
of  the  Chinese  rebellion  in  1920.  He  later  described  the 
anti-American  outbreak  on  the  Yangtse  and  he  was  in 
Siberia  watching  Kolchak  make  the  last  stand  against 
the  Bolsheviks.  He  assisted  two  other  Americans  in 
the  rescue  of  Dr.  A.  L.  Shelton,  Christian  Missionary, 
kidnapped  for  ransom  by  Yunnan  bandits  and  held 
captive  for  two  months  near  the  Tibet  border.  He  has 
been  a  newspaper  editor  and  foreign  correspondent 
for  a  quarter  of  a  century.    He  thrives  on  action. 

He  knows  newspaper  editors  all  the  way  from  the 
Maine  border,  where  they  smuggle  rum,  to  the  Cali- 
fornia border,  where  they  smuggle  Orientals.  He  is 
going  to  organize  a  proof  press  and  let  every  newspaper 
in  the  United  States  know  what  transpires  in  this 
Radio  Corporation  matter.  And  maybe  we  can  induce 
Charlie  Erbstein  to  broadcast  it.    Let's  go! 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour  5 


Install  genuine  All- American  Audio  Transformers. 
Two  of  these  instruments,  fitted  into  any  set  not  al- 
ready equipped  with  them,  will  give  the  receiver  greater 
loud-speaker  volume  with  remarkable  purity  of  tone. 
ALL'AMERicANTransformers  are  so  designed  that  they 
amplify  fundamentals  and  harmonics  equally,  through' 
out  practically  the  entire  audible  range.  Hence,  voice 
and  tones  are  reproduced  faithfully. 

The  standards  of  precision  to  which  All-Americans 
are  made,  have  led  to  their  adoption  as  standard 
equipment  on  all  the  better  sets. 

Insist  upon  All- Americans  :  the  Audio  Transform- 
ers  which,  through  sheer  merit,  have  become  the  largest 
selling  transformers  in  the  world.  3  to  1  Ratio, 
$4.50;  5  to  1  Ratio,  $4.75;  10  to  1  Ratio,  $4.75. 


Use  All-American  Super-Fine  Parts,  and  you  can 
have  an  intermediate-frequency  receiver  embodying 
all  the  most  advanced  features  known  in  Radio. 

Super-Fine  Parts  are  easily  installed.  No  critical 
adjustments  are  necessary.  Operation  is  smooth  and 
flawless.  And  every  part  is  All- American — if  you 
are  a  Radio  Fan  you  know  what  that  means!  Sets 
built  with  Super-Fine  Parts  are  unsurpassed  for  selec- 
tivity, range,  volume,  and  tone  quality.  Practically 
any  station  in  the  country  can  be  brought  in  on  the 
loud-speaker.  Interference  from  local  stations  is  com- 
pletely eliminated.  Reliability  is  assured  through 
All-American  precision  in  manufacturing.  Super- 
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in  radio  broadcast  reception.  Price,  $26.00 


J 


ALL-AMAX  JUNIOR 

An  AU-American  One-Tube  Reflex 

This  is  the  ideal  set  for  the  youthful 
beginner  in  Radio.  It  comes  completely 
mounted  on  panel  and  baseboard,  and 
can  be  easily  wired  in  one  delightful 
evening  with  the  aid  of  clear  photo- 
graphs and  a  43-page  instruction  book. 
Easy  to  tune — as  selective  as  a  multi- 
tube  set — has"crystal"  tone  quality — 
volume  enough  for  speaker  operation. 
It  brings  in  far-distant  stations,  and 
tunes  out  the  locals. 

Price,  complete  (semi- finished)  $22.00 


The  Radio  Key  Book 

Will  help  anyone  to  hear  far- 
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tested  hookups — diagrams  of 
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Sent  for  10  cents,  coin  or  stamps 


RAULAND  MFG.  CO. 

2680  Coyne  St.,  Chicago 
Pioneers  in  the  Industry 


ALL-AMAX  SENIOR 

An  All-American  Three-Tube  Reflex 

A  complete  receiver  of  the  highest 
type.  Great  range  and  selectivity  are 
provided  by  three  stages  of  tuned  and 
SELF-TUNED  Radio  Frequency 
Amplification.  A  crystal  detector  and 
two  stages  of  Standard  ALL-AMER- 
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Price,  complete  (semi-finished)  $42.00 


I 


1^**  TRADE  MARK  *^l 

Largest  Selling  Transformers  in  the~World 


*     Tested  and  Approved  by  RADIO  AGE     * 


I  have  trained  2274  men   * 


to  make  big  money  in  Radio 

I  can  do  the  same  for  you 


WHO  were  these  men?  They  came  from  all 
walks  of  life.  I  have  just  looked  up  the 
record  of  ten  of  them.  One  school 
teacher,  one  railroad  man,  one  drug  clerk,  one 
die-maker,  one  electrician,  one  insurance  man, 
one  farmer's  son,  one  travelling  salesman. 
How  much  are  they  making?  $50  to  $500  a  week. 
The  $50  men  are  mostly  those  who  give  me 
their  spare  time.  A  great  many  of  my  repre- 
sentatives start  that  way. 
How  much  did  they  know  about  radio  at  the 
start?  Very  little,  in  many  cases  nothing.  Lack 
of  radio  knowledge  is  not  a  handicap.  In  fact, 
I  rather  prefer  the  man  who  hasn't  delved  too 
deeply  into  radio  theory.  We  have  our  own 
methods — they  are  successful — and  the  man 
with  nothing  to  unlearn  makes  the  biggest 
success  of  our  plan. 

Many  of  the  men  who  have  made  the  biggest 
money  selling  Ozarka  instruments  never  sold 
anything  before  in  their  lives.  Sales  experience 
naturally  would  be  of  some  value,  but  it  is  not  abso- 
lutely necessary.  Unlike  other  articles,  a.  radio  instru- 


ment does  its  own  talking.  Your  demonstrations  are 
given  during  the  evenings,  which  is  possibly  your  spare 
time.  In  the  hands  of  the  man  who  knows  the  instru- 
ment it  will  deliver  its  best,  and  you  can  safely  put  it  in 
competition  with  any  instrument  on  the  market  today, 
regardless  of  its  price. 

The  man  I  want  is  known  in  his  community  as  upright 
and  reliable — a  man  whose  word  is  as  good  as  his  bond 
— a  man  who  has  lived  in  his  community  long  enough  so 
that  his  fellow  men  know  him  and  know  the 
real  type  that  he  is.    He  may  not  have  any,, 
considerable  amount  of  money,  but  he  has, 
a  little;  in  fact,  in  many  cases  the  man  t 
is  particularly  interested  in  my  plan  is  t 
one  who  is  having  rather  a  hard  timej 
making  ends  meet.  He  is,  however,  t 
type  of  man  who  would  not  handle  any- 
thing unless  he  was  thoroughly  con- , 
vinced  of  its  merit.   If  you  are  this  , 
kind  of  a  man  and  are  really  sincere 
in  wanting  to  improve  your  finan- 
cial conditions,  I  will  be  very  glad 
to  tell  you  of  the  Ozarka  Plan.   I 
can  train  you  to  make  consider- 
able more  money  than  you  are 
now  imk  ing.   I  have  done  this 
with  2274  men  in  the  past  two 
years,  and  I  will  do  it  for 
you  if  you  wiii  do  your  part. 


This  Button  identifies  Ozarka  Rep* 
resentative  in  your  city— your  assur* 
ance  of  complete  radio  satisfaction 


his  large 
Book  tells 

how  to  make 
$100  per  week 

under  Ozarka  Plan 


Ozarka 
four  tube 
radio  for 

opera- 
tion with 

loud 
speaker 
as  low  as 


w 


The    Ozarka    Plan    is   fully 
described  in  a  large  illustrated  book. 
I  will  send  a  copy  to   men  who  are 
willing  to  tell  me  fully  about  themselves. 
The  Ozarka  book  is  a  true  story  of  life,  of 
men,  of  why  they  fail,  and  how  they  succeed.  It 
tells  how  men  are  carving  out  futures  for  them- 
selves in  this  fascinating  business  of  radio. 

In  territory  not  now  covered,  I  want  the  right 
man.  If  you  feel  qualified  and  are  willing  to  put 
forth  the  necessary  effort  to  obtain  a  splendid, 
profitable  business  of  your  own,  write  me  and 
say  "Send  your  Ozarka  Plan  Book  No.  100." 
It  may  be  the  turning  point  in  your  life.  Don't 
fail  to  mention  the  name  of  your  county. 

Ozarka,  Inc. 

871   Washington  Blvd.,  Chicago 


*    Tested  and  Approved  by  RADIO  AGE    * 


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USq  Magazine  of  the  Hour 


M.  B.  Smith 

Business  Manager 


A   Monthly  Publication 

Devoted  to  Practical 

Radio 


Frederick  A.  Smith 

Editor 


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Hr,s£  Super-Stations  Licensed — 

NEW  Wavelengths  a  PROBLEM 


WASHINGTON,  D.  C— What  to 
do  about  the  reallocation  of  wave- 
lengths to  broadcasting  stations 
as  recommended  by  the  Third  National 
Radio  Conference  at  Washington?  What 
to  do  is  right,  for  although  the  Con- 
ference adjourned  over  two  months  ago, 
the  conferees  blissfully  going  respective 
ways  feeling  their  recommendations  had 
solved  the  situation,  little  as  yet  has 
been  accomplished. 

In  fact,  they  have  left  at  Secretary 
Hoover's  doorstep  a  problem  as  com- 
pared to  which  the  solution  of  a  Chinese 
cross-word  puzzle  would  be  easy.  Two 
months'  time  is  not  ordinarily  con- 
sidered a  long  period  when  it  is  remem- 
bered that  Rome  was  not  built  in  a  day, 
but  the  way  in  which  things  are  popping 
in  radio,  sixty  days'  delay  is  the  equiva- 
lent of  years  in  other  fields  of  endeavor. 
Far  from  being  able  to  afford  relief  to 
existing  broadcasting  stations  in  this 
period  of  drifting,  the  situation  is  becom- 
ing more  complicated  by  the  fact  new 
broadcasting  stations  are  springing  up 
like  mushrooms. 

How  It  Started 

THE  pressure  upon  the  officials  at  the 
Department  of  Commerce  is  terrific. 
W.  D.  Terrell,  Chief  Supervisor  of  Radio, 
to  whom  the  immediate  solution  is  en- 
trusted, attacking  the  Class  "B"  station 
situation  as  a  starting  point,  lost  no 
time  putting  the  Radio  Conference 
recommendations  up  to  the  government 
district  radio  inspectors  throughout  the 
country  with  instructions  for  them  to 
get  into  touch  with  owners  of  stations. 

And  then  the  trouble  began! 

So  discouraging  have  been  the 
reports  received  from  certain  of  these 
inspectors — key  men,  in  fact — that  the 
plan  of  the  Conference  now  appears  to 
be  as  far  from  being  carried  out  as  the 
day  the  reccomendations  were  agreed 
upon. 

In  fact,  unless  miracles  are  performed 
in  the  congested  broadcasting  areas,  I 
do  not  believe  the  present  plan  can  ever 
be  carried  out,  and  I  base  this  prediction 
upon  a  talk  I  had  with  a  high  govern- 
ment official  who  summed  up  the  situa- 
tion as  follows: 

The     third     radio   conference   recom- 


By  ROBERT  D.  HEINL 

New  Broadcasters 
"Stump"  Conferees 


mended  an  extension  of  the  Class  B  band 
of  wavelengths  from  288  down  to  280 
meters  and  the  removal  of  Class  C  sta- 
tions from  the  wavelength  of  360  meters, 
giving  to  Class  B  stations  the  entire 
band  from-280  to  545  meters. 

Transfers  Planned 

Steps  have  already  been  taken  to 
transfer  the  Class  C  stations  to  either  A 
or  B  and  to  shift  the   Class  A  stations 


(Photo  by 
Harris 
&  Ewirjg) 


W.  D.  Terrell,  the  Governments  chief 
radio  supervisor,  on  whose  shoulders  rests 
the  burden  of  reallocating  the  maze  of  tan- 
gled wavelengths.  He  also  is  assisting 
Secretary  Hoover  in  apportioning  the  first 
assignment  for  increased  power. 


between  280  and  286  meters  to  the  band 
below  280  meters. 

The  continuing  committee  proposed 
by  the  conference  to  reallocate  the  broad- 
casting wave  lengths  prepared  a  plan 
covering  the  Class  B  stations  as  they 
existed  or  were  contemplated  on  October 
22nd.  It  was  necessarily  tentative,  it 
not  being  definitely  known  at  that  time 
how  many  stations  would  have  to  be 
provided  for  or  how  difficult  it  might  be 
for  the  owners  to  comply  with  the  plan. 
This  plan  was  referred  to  the  super- 
visors of  each  district  to  be  submitted 
by  them  to  the  owners  of  the  stations 
involved  to  ascertain  what  difficulties 
might  arise  as  to  particular  stations,  and 
to  prevent  as  far  as  possible  any  hitch 
in  its  adoption. 

New  Troubles  Arise 

T^HREE  or  four  of  the  districts  have 
-*-  already  reported  that  the  plan  is 
acceptable.  The  other  districts,  however, 
are  experiencing  considerable  difficulty 
because  of  the  additional  new  Class  B 
stations  not  contemplated  and  conse- 
quently not  taken  into  consideration 
when  the  plan  was  prepared. 

There  are  forty-seven  Class  B  wave- 
lengths available  for  the  entire  United 
States,  even  if  two  stations  are  put  on 
each  wavelength,  which  means  undesir- 
able division  of  time.  There  are  only 
ninety-four  operating  channels. 

At  the  present  time,  there  are  sixty- 
four  Class  B  stations  in  operation. 

The  Bureau  has  been  advised  that 
seven  Class  C  stations  and  fourteen 
Class  A  stations  are  preparing  to  enter 
Class  B.  In  addition  to  this,  there  are 
nineteen  stations  under  construction  or 
proposed,  which  are  planning  to  enter 
Class  B,  giving  us  a  total  of  104  Class  B 
stations  to  be  provided  for  on  ninety-four 
duplicated  channels. 

Many  of  these  had  not  been  heard  of 
at  the  time  of  the  conference.  Thirteen 
of  these  Class  B  stations  are  west  of  the 
Rocky  Mountains,  and  if  the  power  of 
these  stations  is  not  increased  consider- 
ably, they  can  probably  use  the  wave- 
lengths now  being  used  on  the  Atlantic 
Coast,  as  they  have  been  doing  for  the 
past  eighteen  months.  If  this  can  be 
continued  it  will  leave  ninety-one  Class  B 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


stations  to  be  placed  on  the  ninety-four 
channels,  assuming  that  none  of  them 
obtains  a  separate  wavelength  and  that 
all  must  divide  time  at  least  two  ways. 

Because  of  the  increase  in  new 
Class  B  stations  mentioned  above, 
it  is  necessary  to  give  new  con- 
sideration to  the  plan  now  in 
the  hands  of  the  supervisors 
and  complete  remodeling  may 
be  necessary.  The  fundamental 
difficulty  is  that  stations  are 
increasing  so  rapidly  that  no 
general  plan  can  have  anything 
like  permanence. 

Department  Swamped 

WASHINGTON,  D.  C,  [Special]  The 
Department  of  Commerce  is  so 
busy  these  days  trying  to  fit  half  enough 
wavelengths  to  twice  too  many  stations, 
that  complaints  of  interference  do  not 
elicit  very  hearty  or  quick  responses.  This 
is  unavoidable,  officials  say, 
so  fans  must  content  them- 
selves with  the  fact  that  the 
Department  radio  chiefs  are 
snowed  under  with  requests 
for  Class  B  wavelengths. 

With  only  fifty-three 
available  wavelengths 
designated  by  the  confer- 
ence for  about  sixty  sta- 
tions, the  government  is 
now  asked  to  allocate  them 
to  110  B  stations.  There 
are  sixty-four  B  Stations 
already  operating,  and  forty- 
six  either  under  construc- 
tion or  contemplated,  mak- 
ing the  application  of  the 
original  allocation  plan  prac- 
tically impossible.  Despite 
difficulties  in  numbers,  there  are  local 
situations  to  be  met,  and  although  four 
of  the  supervisory  districts  are  apparently 
fixed  up,  other  supervisors  are  having 
difficulties  similar  to  the  trouble  at  head- 
quarters in  Washington;  too  many  Class 
B  stations  for  a  division  of  time  on  the 
available  wavelengths.  Either  an  en- 
tirely new  plan  will  have  to  be  developed, 
with  less  space  between  the  channels 
used,  or  more  wavelengths  will  have  to 
be  secured  from  other  services.  An 
alternative  would  be  to  have  stations 
divide  time  three  ways,  which  it  is  hoped 
may  be  avoided. 

Imagine  if  you  can  the  howl  at  head- 
quarters when  the  writer  asked  when  the 
new  list  of  wavelength  allocations  would 
be  available.  He  is  not  permitted  to 
quote  the  replies,  but  they  varied  all  the 
way  from  six  months  to  a  year,  with 
requests  for  a  method  of  redistributing 
them. 

The  Department  is  working  on  a  new 
plan  of  allocating  wavelengths,  and 
expects  to  try  the  method  out  by  tests 
fairly  soon  to  see  if  the  scheme  is  prac- 
tical. It  is  hoped  that  by  the  first  of  the 
year  that  a  satisfactory  distribution  will 
be  in  operation,  but  nothing  definite 
can  be  said  at  this  writing. 

With  the  coming  of  the  Winter  months, 
with  better  radio  reception  and  more 
listening-in,  Department  of  Commerce 
>fficials  point  out  that  super-sensitive 
sets  which  are  not  super-selective  must 
be  cured,  if  interference  is  to  be  avoided 


and  trouble  in  reception  minimized. 
The  fans  themselves  can  better  reception, 
it  is  believed,  by  improving  their  sets 
and  learning  to  operate  them  properly. 
Due  to  this  fact,  the  Departmental  super- 
visors and  inspectors  may  be  expected  to 
refuse  to  consider  complaints  unless  sets 
are  described.  There  is  nothing  doing  if 
poor  receivers  are  used.  If  a  receiver  is 
like  a  sponge,  absorbing  everything,  the 
Department  could  do  nothing  to  relieve 
interference  unless  it  caused  all  except 
one  station  to  close. 

There  are  thousands  of  non-selective 
crystal  sets  on  the  market  and  in  use, 
which  are  impractical  for  anything  but 
local  reception  where  one  station  only 
is  on  the  air  at  a  given  time.  If  a  set  is  not 
a  two  or  more  circuit  set,  it  will  probably 
pick  up  everything.  Practically  all  crystal 
sets  are  of  the  single  circuit  variety.  In 
this  way  many  small  sets  pick  up  a  lot  of 
preventable  interference,  such  as  the  so- 


MORE  STATIONS  INCREASE  POWER 

TC*OUR  more  Class  "B"  broadcasting  stations  which  applied  for 
■*-  increased  power  up  to  1,500  watts  were  licensed  temporarily 
last  month  under  the  regulations  providing  that  no  additional 
interference  shall  be  caused. 

Increased  power  has  been  authorized  for  KYW,  the  Westing- 
house  radiophone  at  Chicago;  WBZ,  owned  by  Westinghouse  at 
Springfield,  Mass. ;  KFI,  owned  by  Earl  C.  Anthony  at  Los  Angeles, 
Calif. ;  and  WEAF,  of  the  American  Telephone  and  Telegraph 
Company,  at  New  York  City.  The  first  station  so  licensed  was 
WTAM,  at  Cleveland,  Ohio. 

This  puts  five  of  the  Class  "B"  stations  in  a  position  to  broad- 
cast at  an  increased  range.  Many  radio  experts  believe  that  this 
arrangement  will  result  in  better  broadcasting,  "if"  it  does  not 
blanket  neighboring  stations. 


again  a  possibility  of  enactment  of  much 
needed  radio  legislation  in  the  passage 
of  the  so-called  White  bill,  named  after 
Congressman  Wallace  H.  White,  Jr.,  of 
Maine.  The  bill,  which  was  originally 
introduced  by  Mr.  White  in  the  first 
session  last  February,  now  includes  the 
features  of  a  Senate  bill  of  slightly  more 
limited  scope.  The  bill  has  been  favor- 
ably reported  to  the  House  by  the  Com- 
mittee on  Merchant  Marine  and  Fish- 
eries. During  the  last  session,  Congress- 
man Greene  of  Massachusetts,  chairman 
of  that  committee,  requested  from  the 
House  Rules  committee  a  special  rule 
which  would  make  it  in  order  for  the 
House  to  consider  the  radio  bill  out  of 
regular  order  and  under  limited  debate, 
which  would  expedite  action. 

In  view  of  the  urgency  of  the  legisla- 
tion, it  is  expected  Mr.  Greene  will  renew 
the  request  at  this  session  and  if  so  it  is 
anticipated    that    the    Rules    committee 
may   grant  it.     If  this   rule 
can  be  secured,  proponents 
of  the   bill   are  confident  it 
would  pass  by  a    comfort- 
able   majority.     The   mea- 
sure would  then  go  to  con- 
ference   for    Senate   action 
on  the  additions   made   by 
the  House. 


M1 


called  man-made  interference  from  legiti- 
mately operated  and  electrically  driven 
machinery  and  apparatus. 

Many  manufacturers  using  electric 
power  and  apparatus  emitting  electrical 
interference  are  trying  to  eliminate  their 
radiations,  so  as  to  decrease  the  broad- 
cast listener's  troubles.  But  it  often 
costs  considerable  money  and  is  frequent- 
ly unsuccessful. 

By  the  use  of  simple  wave  traps,  con- 
siderable local  interference  from  other 
stations  and  electrical  devices  may  be 
eliminated,  it  is  pointed  out.  So  it  is  up 
to  the  fan  to  aid  his  brother  fans  and 
the  Government  by  improving  his  own 
set.  Some  fans  will  find  that  by  using 
a  two-circuit  set  or  a  tuner  that  they 
can  select  either  of  two  local  stations 
operating  simultaneously,  with  a  reason- 
aisle  separation  between  their  wave- 
lengths, as  is  used  in  the  present  wave- 
length assignment.  Otherwise  they  will 
find  it  impossible  to  listen  in  when  two 
or  more  stations  are  operating  at  once. 
Unless  fans  learn  to  tune  their  sets,  they 
will  get  even  the  amateur  stations  on  the 
short  waves  below  200  meters. 

Before  you  complain  the  next  time, 
be  sure  your  set  is  a  reliable  one  and  that 
it  is  operating  properly,  and  that  you 
have  taken  the  usual  precuations  to  pre- 
vent the  necessity  of  writing  to  govern- 
ment inspectors. 

Radio  Legislation 

With    Congress    in    session,    there    is 


First    "Supers"    On    Air 

IDDLE  Western  fans 
are  now  getting  their 
first  taste  of  "super-power" 
with  the  advent  of  WTAM, 
the  Willard  Battery  Sta- 
tion at  Cleveland,  O.,  into 
the  ranks  of  high-power 
broadcasters. 

WTAM  came  on  the  air 
about  the  first  of  December  with  in- 
creased wattage,  presumably  1,500  watts. 
Fans  living  in  the  vicinity  of  Cleveland 
report  that  very  close  tuning  was  expe- 
rienced with  WTAM's  new  power,  but 
others  with  weaker  sets  said  they  were 
unable  to  tune  the  station  out. 

In  many  cases  a  wave  trap  helped  to 
eliminate  WTAM,  depending  on  the 
position  of  the  receiving  aerial. 

In  New  York  State  and  in  the  Chicago 
district,  WTAM  came  in  with  loud 
speaker  volume  on  three  tubes  in  every 
instance,  and  most  fans  who  were  ques- 
tioned reported  that  WTAM  could  be 
"heard  all  over  the  house,"  so  strong 
was  the  apparatus.  However,  fans  three 
hundred  or  more  miles  from  WTAM 
reported  it  could  be  tuned  out  by  turning 
the.  dial  three  or  four  points,  so  no  inter- 
ference  was  caused   in   that   respect. 

In  Chicago  it  was  found  that  WTAM 
could  barely  be  heard  when  WEBH, 
on  370  meters,  or  WGN,  on  360  meters, 
were  broadcasting.  WTAM  has  a  390 
wavelength. 

From  preliminary  reports,  then,  it 
appears  that  small  sets  located  near  the 
super-power  stations  will  be  the  ones  to 
suffer  most,  and  unless  they  adjust  their 
sets  or  equip  them  with  a  wave  trap, 
it  is  unlikely  they  will  be  able  to  tune 
out  the  strong  broadcasters. 

The  Government  is  watching  initial 
experiments  closely,  in  accordance  with 
its  promise  that  super-power  will  be 
abolished  if  interference  is  excessive. 


RADIO  AGE  for  January,  1925 


The  Mahazine  of  the  Hour 


Results  with  Radio  Frequency 

R.  F.  Amplification 
Best  for  Distance, 
But  Fan  Must 
Get  the  Right 
Transformer 

By  ARMSTRONG  PERRY 


EXPERTS  agree  that  for  DX  work 
in  radio  a  good  radio-frequency 
amplifier  is  needed.  They  have 
to  agree,  because  it  can  be  and  has  been 
proven,  mathematically,  experimentally 
and  in  practice  among  radio  users,  that 
radio-frequency  amplification  increases 
the  weak  signals  to  a  greater  degree  than 
the  stronger  ones.  Naturally,  the  signals 
from  distant  stations  are  the  weakest, 
other  things  being  equal,  therefore  they 
are  to  be  helped  most  by  radio-frequency 
amplification. 

A  necessary  part  of  an  efficient  radio- 
frequency  amplifier  for  use  with  wave- 
lengths within  the  broadcasting  band 
is  a  transformer,  through  which  the 
amplifier  tubes  are  coupled  together  or 
the  last  amplifier  tube  coupled  to  the 
detector.  For  longer  wavelengths,  re- 
sistance coupling  may  be  used  with  good 
results,  but  resistance-coupled  ampli- 
fiers are  not  usually  satisfactory  for 
wave  lengths  below  1,000  meters. 

If  amplification  of  power  were  the 
only  thing  to  be  accomplished,  the  con- 
struction of  a  radio-frequency  amplify- 
ing transformer  would  be  comparatively 
simple.  Six  stages  of  amplification  will 
make  a  loud  speaker  roar  like  a  factory 
whistle. 

Sounds   Must   Be   Intelligible 

IT  will  vibrate  a  loud  speaker's  dia- 
phragm so  powerfully  that  it  will 
throw  a  stream  of  air  strong  enough  to 
blow  out  a  match.  But  all  amplification 
when  applied  to  currents  carrying  the 
characteristics  of  voice  or  music,  causes 
some  distortion,  and  the  radio- frequency 
amplifying  transformer  will  make  sounds 
unintelligible  unless  it  is  constructed 
and  operated  with  the  greatest  nicety. 
It  distorts  less  than  the  audio-frequency 
amplifier  but  either  is  a  difficult  piece 
of    apparatus   to    design    and    build. 

Perhaps  the  greatest  problem  that 
confronted  the  builder  or  user  of  radio- 
frequency  amplifying  transformers  for 
short  wavelengths  was  the  difficulty  of 
obtaining  a  transformer  that  would 
amplify  equally  over  a  wide  range  of 
wavelengths  within  the  broadcasting 
band.  It  was  not  very  difficult  to  pro- 
duce one  that  had  a  very  good  peak 
somewhere.  If  the  user,  fishing  for  a  DX 
station,  happened  to  catch  one  whose 
wave  corresponded  to  the  frequency  at 


Above  is  an  artist's  picturization  showing  how  Radio  Frequency  reaches  out 
and  helps  the  "DX"  listener  to  amplify  weak  signals  which  he  could  not  gel 
otherwise.  If  the  set-builder  or  buyer  gets  the  right  R.  F.  transformers,  they 
will  bring  him  all  signals  within  the  range  for  which  they  were  constructed. 


which  the  transformer  was  most  efficient, 
he  had  something  to  tell  the  neighbors. 
But  he  might  fish  in  vain  for  a  much 
nearer  and  more  powerful  station  without 
ever  getting  it.  This  made  radio-fre- 
quency amplification  unpopular  at  the 
start,  except  with  experimenters  who 
appreciated  what  a  great  future  it  had 
if  properly  developed. 

Long  before  radio  broadcasting  began, 
P.  D.  Lowell,  of  the  Radio  Laboratory 
of  the  United  States  Bureau  of  Standards, 
started  experiments  on  the  amplification 
of  short  waves.  Brent  Daniel  of  the 
Bureau  took  up  the  work  after  Mr. 
Lowell  had  established  the.  fact  that  a 
<-adio-frequency  transformer  could  be 
built  that  would  cover  a  fairly  wide  wave 
band.  He  developed  the  transformer 
just  at  the  beginning  of  the  broadcasting 
era.  Imitators  immediately  began  that 
old  game  of  making  "something  just  as 
good."  The  transformers  that  some  of 
them  built  were  developed  hurriedly 
because  the  radio  trade  was  growing 
rapidly  and  the  loss  of  a  day  in  getting 
into  the  patent  office  might  mean  the 
loss  of  a  good  many  dollars.  The  radio 
education  and  experience  of  some  manu- 
facturers effectively  prevented  their  mak- 
ing a  successful  imitation  or  substitute. 
The  closest  study  of  a  piece  of  appara- 
tus so  apparently  simple  but  really  so 
intricate,  by  even  an  experienced  radio 
man,  cannot  reveal  at  once  all  the  knowl- 
edge of  the  device  that  was  acquired  by 
the    man   in    whose   brain    it   was   born. 

Capacity  Effects  Hinder 

AS  stated  in  "The  Principles  Under- 
lying Radio  Communication,"  a 
book  prepared  by  the  Bureau  of  Stand- 
ards for  the  Signal  Corps,  "  .  . 
for  short  wavelengths,  particularly  for 
wavelengths  of  less  *han  300  meters, 
radio-frequency  amplification  is  attended 
with  much  difficulty  caused  by  capacity 
effects    between    different    parts    of    the 


circuit."  The  number  of  coils  and  turns 
of  wire  in  a  transformer  make  just  so 
many  component  parts  for  condensers, 
unwanted,  unwelcome,  but  impossible 
to  be  rid  of.  The  experimenters  at  the 
Bureau  met  this  difficulty  in  clever 
fashion. 

Making  use  of  the  well-known  fact 
that  the  combined  capacities  of  condens- 
ers connected  in  series  is  less  than  the 
capacity  of  any  one  of  them  when  oper- 
ating alone,  they  wound  both  the  pri- 
many  and  secondary  coils  in  a  number  of 
groups.  These  were  so  spaced  from  each 
other  and  from  the  core  that  they  formed 
a  series  of  condensers  with  but  a  very 
small  combined  capacitv.  Even  the 
wires  that  connected  coil  with  coil  were 
kept  well  separated,  to  minimize  the 
capacity  between  them.  This  increased 
both  the  amplification  and  the  range  of 
wavelengths  over  which  the  transformer 
would  operate. 

The  coupling  between  primary  and 
secondary  was  found  to  be  very  critical. 
A  change  of  a  sixteenth  of  an  inch 
altered  the  characteristics  of  the  trans- 
former. The  spacing  between  the  sepa- 
rate coils  of  the  primary  and  secondary 
was  even  more  critical.  A  difference  of  a 
thousandth  of  an  inch  between  any  two 
coils  made  a  decided  difference  in  the 
characteristics.  To  insure  accuracy 
and  permanency,  each  coil  was  placed 
in  a  slot  machine  and  micrometered  in  a 
square  tube  of  insulating  material. 

The  size  of  the  wire  in  the  coils  was 
found  to  be  important,  because  the  finer 
the  wire,  the  closer  together  the  turns 
will  lie  and  the  smaller  the  capacity 
between  them  will  be.  No.  38  wire  was 
found  to  be  the  best.  Beside  this  some 
human  hair  looks  large. 

The  ratio  of  the  turns  of  wire  in  the 
primary  to  those  in  the  secondary  was 
still  another  problem  that  had  to  be 
worked  out  with  painstaking  exactness. 
The  radio  novice   is  often   intrigued   by 


10 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


SLOTS 

/&g 

; 

PRlMARy 
SecONOWV 

complete  transformers  and  put  all  their  band. 
best  features  together  to 

produce  the  one  he  was  Tne  Heart  of  the  Set 

after.     When   he  finished  The   point  of  the  story  is  this:     No 

it,  he  found  he  could  bring  matter  how  many  stages  of  amplification 

in  Kansas  City  on  a  two-  you  have,  no  matter  how  good  a  detector, 


the  allurements  of  a  high  ratio.  "Ten  these  details,  but  the  government  expert  and  then  falls  very  slowly  to  560,  which 
to  one!  Gee,  ten  times  as  much  signal  who  worked  them  out  had  to  build  127  is  the  upper  edge  of  the  broadcasting 
strength!  Me  for  it!"  Theoretically,  it  - 
can  be  worked  out  some- 
thing like  that.  In  prac- 
tice, the  distortion  and 
the  difficulty  of  control 
nullify  the  theoretical  ad- 
vantage. The  Bureau 
found  that  a  1  to  1  ratio 
between  the  windings  gave 
very  satisfactory  amplifi- 
cation. (As  the  French- 
man said:  "No  doubt 
they  are  right,  but  God 
knows  eet  ees  impossi- 
ble!" 

A  ratio  of  1  to  1  1-3  is 
the  maximum.  This  is 
obtained  not  by  addi- 
tional slots  and  coils,  but 
by  additional  turns  of  wire 
in  the  slots  at  the  secon- 
dary end  of  the  tube. 


Using    Iron    and    Steel 
Cores 

'"THE  core  was  another 

problem.  It  had  been  known  for  a 
long  time  that  iron-cored  transformers 
would  give  better  results  for  some  pur- 
poses than  air-core  transformers.  The 
core  broadens  the  waveband  over  which 
the  transformer  is  efficient.  It  also 
reduces  the  turns  of  wire  necessary  in 
the  coils  and  the  capacity  that  is  so  un- 
desirable. But  the  use  of  iron  or  steel 
cores  in  radio-frequency  amplifying  trans- 
formers had  not  been  considered  as  prac- 
tical until  the  Bureau  of  Standards 
demonstrated  that  it  was.  Transformer 
action  depends  upon  the  building  up  and 
collapse  of  lines  of  magnetic  force  about 
the  wires  in  the  windings. 

In  order  to  get  the  desired  increase 
of  voltage  which  the  iron  core  is  capable 
of  assisting,  the  core  must  reach  the 
magnetic  saturation  point  on  every 
oscillation.  In  radio-frequency  trans- 
formers, this  means  that  the  lines  of 
magnetic  force  must  penetrate  and 
saturate  the  iron  core  a  million  times  per 
second  if  300-meter  waves  are  being 
received.  This  is  impossible  unless  the 
core  is  made  up  of 
exceedingly  thin 
sheets.  A  thick- 
ness— or  thinness! 
■ — of  three  and  one- 
half  thousandths  of 
an  inch  was  un- 
successful. 

It  had  to  be  re- 
duced to  two  thou- 
sandths  before 
success  was 
achieved.  Seventy- 
five  of  these  ex- 
tremely delicate 
sheets  of  metal,  or 
one  sheet  folded 
seventy-five  times, 
makes  up  a  core 
about  the  size  of  a 
square  lead  pencil. 
The  core  was  well 
insulated  to  reduce 
losses. 

It  is  a  simple 
matter  to  describe 


Slots  are  cut  into  each  end 
of  the  tube,  the  windings 
being  laid  into  these  slots. 
The  tube  is  closely  packed 
with  the  iron  laminations 
which  form  the  core.  Wind- 
ings are  of  fine  wire,  and 
are  connected  from  one  to 
the  other  as  above  indicated. 


foot  loop,  and  K.  C.  is  a 
long  way  from  Washing- 
ton. Dr.  Rogers,  inventor 
of  submarine  and  under- 
ground radio  devices, 
brought  in  broadcasts  from 
England  by  using  these 
transformers,  long  before 
the  recent  furore  about 
hearing  from  the  other 
side  of  the  Atlantic. 

Part  of  the  job  has  been 
to  compare  the  transfor- 
mer developed  by  the 
Bureau  with  those  pro- 
duced by  others.  The 
curves  tell  the  story. 
Three  of  them  gave  no 
sound  at  all  in  the  phones 
on     waves 


below  300  meters.  Now 
that  the  broadcasting  band 
is  going  downward,  some 
folks  are  out  of  luck.  One 
transformer  had  two  good 
humps,  like  a  camel,  one 
at  about  250  meters  and 
the  other  at  350  meters. 
Unfortunately,  the  recent 
conference  called  by  Mr. 
Hoover  did  not  assign 
wavelengths  to  fit  the 
humps  of  radio-frequency 
transformers.  Another 
type  of  transformer  gave  a 
fairly  high  and  broad  peak 
from  320  to  360  meters. 

Outside  of  that,  nothing 
doing.  Two  others  rose 
sharply  out  of  the  silence 
between  300  and  350 
meters,  then  faded  away. 
The  one  developed  by  the 
Bureau  and  used  in  this 
test  begins  going  strong  at  200  meters, 
is  better  at  300,  reaches  its  peak  at  360 


The  turns  of  No.  38  wire 
are  wound  in  slots  in  a 
series  of  continuous  but 
divided  coils.  The  windings 
slots  are  at  opposite  ends  of 
the   tubing   as   shown  above. 


M\VEL£n/a-m 


tuner,  or  audio-frequency  amplifier  your 
set  contains,  the  first  tube  and  the  first 
transformer  control  the  oscillations  of 
the  entire  set.  If  the  transformer  retuses 
to  function  at  the  wavelength  of  the 
station  you  are  fishing  for,  you  will  not 
hear  it — that's  all!  There  are  many 
radio-frequency  amplifiers  on  the  market 
and  the  manufacturers  and  dealers  are 
mostly  honest  folks.  They  are  not  in 
the  habit  of  emphasizing  the  weak  points 
of  their  sets  because  there  are  too  many 
strong  points  to  talk  about.  It  is  up  to 
the  customer  to  say  what  band  of  wave 
lengths  he  wants  to  cover  and  make  sure 
that  the  set  he  is  considering  will  do  the 
work  he  wants  done.  It  is  perfectly  fair 
to  ask  for  a  demonstration  before  pur- 
chasing, or  to  purchase  on  approval. 

One    big   advantage   of 
the     type     of     radio-fre- 
quency amplifier  that  had 
its    beginning    in    the 
Bureau    of    Standards    is 
that  it  is  a  plug-in  propo- 
sition.    The  waveband  of 
a  receiver  can  be  changed 
by  taking  out  one  trans- 
former   and    plugging    in 
another,   as  easily  as  the 
electric   reading   lamp  on 
the   library  table   can   be 
plugged    into    the    socket 
on    the    baseboard.      By 
using    the    proper    trans- 
formers, four  or  five  stages 
of  radio-frequency  can  be 
used,    with    easy    control 
and  the  minimum  of  dis- 
tortion.   One  stage  multi- 
plies by  10,000  the  energy 
received  through  the  aerial 
and   two  stages   multiply 
it  by  1,000,000. 
Small,  portable  coil  aerials  can  be  used, 
with  the  advantage  of  their  directional 
effects.     Audio- 
frequency amplifi- 
ers will  bring  the 
sound    up   to    the 
desired  volume. 


A  comparison  between  different  RF  transformers  now  in  use.  The  heavy  line 
indicates  the  best  curve  since  it  covers  the  broadcast  band  with  a  very  satisfactory 
value  of  amplification.  Two  stages  of  amplification  with  UV  199s  were  used 
and  all  transformer  curves  were  obtained  under  the  same  operating  conditions. 


Mr.  Perry  will 
have  another  in- 
teresting article  in 
the  February 
RADIO  AGE. 

Incidentally,  the 
Editor  would  like 
to  know  what  our 
readers'  experien- 
ces have  been  with 
Radio  Frequency 
Transformers. 
What  type  of 
transformers  gives 
best  results  and 
widest  rangeon  the 
broadcast  band  ? 
Write  us  about  it 
and  we'll  print  the 
best  letters. 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


11 


FIG.  1 

SCHEMATIC    CIRCUIT  D1/>GR*M 
FOUR    TUBS    NEUTRODYNE-  REFLEjC  RECEIVER. 


Simplifying  Reception  With 

A  REFLEXED  Neutrodyne 


WITH  the  ever  in- 
creasing demand 
for  a   receiver 
that  will  not  only  reach 
out  to  far  distant  points, 
but  which  will   bring   in 
the  distant  stations  with 
sufficient  volume  to  op- 
erate   a    loud    speaker, 
popularity     has    shifted 
around  from  the  single  circuit  regenera- 
tive receiver  of  a  few  years  ago  to  the 
super-regenerative  set   and  then   to   the 
multitube  radio  fiequency  circuits,  and 
so  on  down  the  line  to  the  more  recently 
improved  circuits. 

After  reflexing  most  of  last  Winter,  the 
neutrodyne  circuit  gradually  took  its 
place  in  the  public  favor  and  it  is  perhaps 
the  most  popular  receiver  today  among 
broadcast  fans.  But  as  time  goes  on,  we 
find  that  each  has  its  limits.  While 
the  super-heterodyne 
great  possibilities  for 
vanced  fan,  it  becomes 
too  expensive  with  its 
maze  of  tubes  and  other 
equipment  and  is  beyond 
the  reach  of  the  average 
fan,  so  he  naturally  looks 
to  less  expensive  equip- 
ment that  will  produce 
exploring  qualities  and 
volume  sufficient  to 
boast  about  with  the 
best  of  them. 

The  set  described  in 
this  article  may  be  just 
what  the  fan  has  been 
looking  for,  as  it  was 
constructed  with  the 
desire   to    get    the   best 


A  Four-Tube  Receiver  That 
Gives  Regular  Six-Tube  Volume; 
Can    Be   Built    at    Small    Cost 


receiver     shows 
the     more    ad- 


By  H.  FRANK  HOPKINS 

A.  E.  E. 

results  possible  without  great  complica- 
tion and  for  the  least  possible  invest- 
ment, combining  the  popular  neutrodyne 
circuit  with  the  reflex  amplifying 
features. 

Simple  Problem 

In  describing  the  how  and  why  of  the 
set,  let  us  take  the  two  features  separate- 
ly, so  as  to  better  understand  why  each 
circuit  was  designed  and  how  it  will 
function  as  a  single  unit.  Then  it  will  be 
a  simple  problem  to  put  the  two  circuits 
together    and     understand   the  principle 


THE  PARTS  FOR  THIS  SET 


1 — Fixed  Mica  condenser.    .0015  mf. — F 
1 — Fixed  Mica  condenser.      .002  mf. — H 

1 — Grid  leak  condenser  .00025  mf.  \ ff 

1 — Grid  leak  resistance  1  megohm  /      ** 
4 — Vacuum  tube  sockets. — M1.M2.M3, 

M4 
2 — Neutralizing  condensers.  Variable — 

•N,   Nl 
3 — Radio  frequency  transformers^*Rl, 

R2,  R3 
2 — Audio  frequency   amplifying   trans- 
formers.    Ratio  5  or  6  to  1 — T,  Tl. 
1 — Cutoff  jack  (If  required). — X 
1 — Phone  jack. — Y 

7 — Binding  posts. — A,  Al,  A2,  B,  Bl, 
B2,   G 


1 — Composition  Panel. 

1 — Composition  Shelf. 

1 — Cabinet.      (If  required). 

Brass  screws,  nuts,  wire,  solder, 
terminals  and  miscellaneous  raw 
materials  used  in  the  construction 
of  the  parts  described  in  this  article. 

1 — Loop'  aerial.     (If  required). 

3 — Variable  condensers. — .0005  mf.  CI, 
C2,  C3 

3 — Composition  dials  for  condensers. — 
CD1,   CD2,   CD3 

1 — Tube    control    rheostat. — 9    to    16 
Ohms.— D 

1 — Composition  dial  for  rheostat. — DD 

1 — Fixed  Mica  condenser. — .001  mf.    E 


•Construction  of  articles    marked   with  asterisk  is  detailed  in  this 
account.     They  can  be  purchased  from  any  reliable  dealer  if  desired. 


of     the     set     described. 
We   will  start   with   the 
neutrodyne     circuit, 
which    is    of   the    tuned 
radio  frequency  type.    A 
radio    frequency    circuit 
amplifies    the    incoming 
signal   before  it   reaches 
the  detector  tube,  much 
the  same  as  a  regenera- 
tive type  of  circuit  amplifies    the  signal 
after   it    has   been    passed   through    the 
detector  tube.       This  is  accomplished  by 
inserting    one    or    more    electron    tubes 
between  the  tuning  element  and  the  de- 
tector  tube,    which    amplifies   the   weak 
signal  currents  received  on  the  antenna 
and  passed  through  the  tuning  element, 
before  it  reaches  the   detector  tube,   the 
same   as  a  regenerative  circuit  amplifies 
them  by  regeneration.     The  only  excep- 
tion is  that  the  circuit  is  free  from  the 
objectionable  oscillation  or  regeneration 
which  is  the  cause  of  howls  and  squeals 
in   the  set  when    regen- 
eration is  pushed  beyond 
its  critical  stage. 

By  connecting  the 
output  side  of  each  radio 
frequency  tube  to  a 
tuned  circuit,  great 
selectivity  is  obtained 
and  interference  is  elimi- 
nated. 

The  neutralizing  or 
balancing  of  the  regen- 
erative effect  makes 
possible  a  simplified 
means  of  tuning,  elim- 
inates oscillation  noises 
and  reproduces  better. 
(Turn  the  page) 


12 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


TOP  V/EH-LOOXtNG 
AT<SHEIF.    COYER 
Of  CA0/NET 

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CONT&OL. 
P/fS/EJL. 


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<?E-rt£/?ftL  /9fir?ANff£A?ENT    or  INSTRUMENTS. 


AWJj 


Harmony  and  simplicity  are  the  characteristic  features  of  this    Neutro-Reflex  receiver.       In  appear- 
ance it   looks   like   a  neutrodyne — in   results   it   is    its   easy  equal,   with    a   smaller  number    of   tubes. 


The  reflex  circuit  is  simply  an  ampli- 
fying feature  whereby  each  amplifying 
tube  is  used  as  a  radio  frequency  ampli- 
fier and  an  audio  frequency  amplifier 
combined. 

The  circuit  operates  much  the  same  as 
a  straight  radio  frequency  circuit  up  to 
the  detector  tube,  but  instead  of  the  out- 
put side  or  plate  of  the  detector  tube 
being  connected  to  the  phones  or  to 
audio  frequency  amplifying  tubes,  it  is 
returned  to  the  input  side  or  the  grid 
of  the  radio  frequency  tube.  The  audio 
frequency  current  is  thus  amplified  by 
the  tube  that  is  simultaneously  amplify- 
ing the  radio  frequency  current  of  the 
signal  before  it  has  reached  the  detector 
tube. 

If  receivers  are  connected  to  a  radio 
frequency  circuit  before  the 
tube,  no  signal  will  be  heard 
do  not  respond  to  a  radio  frequency 
current  until  it  has  been  passed  through 
the  detector  tube  and  changed  to  audio 
frequency,  but  they  will  respond  to  the 
audio  frequency  currents  returned,  or 
reflexed  on  these  tubes  from  a  detector 
tube,  producing  the  same  result  as  a 
straight  additional  audio  frequency  am- 
plifier without  the  use  of  additional 
tubes. 


T^THEN  the  instruments  have  all  been 
"  *  secured,  they  should  be  placed  into 
the  positions  that  they  will  occupy  when 
mounted  into  the  completed  set.  A 
cabinet  of  the  right  proportions  can 
then  be  secured  and  a  panel  and  shelf 
to  fit  the  particular  cabinet  can  then  be 
determined.  This  procedure  may  save 
quite  a  bit  of  laborous  re-arrangement 
later  on. 


Construction  Simplified 

The  parts  used  in  building  the  set  are 
clearly  marked  with  a  designating  letter 
or  number  throughout  this  article  and  on 
the  circuit  diagram  and  construction 
drawings. 

This  method  has  been  found  to  better 
enable  the  prospective  builder  to  more 
easily  distinguish  each  part  and  to  con- 
nect them  properly  into  the  electrical 
circuit,  although  he  may  be  entirely  un- 
familiar with  electrical  circuits  and  con- 
struction. 

The  first  step  in  building  the  receiver 
should  be  to  secure  all  of  the  instruments 
and  material  listed  at  the  bottom  of 
page  11. 


Placing  the  Apparatus 

The  first  step  in  assembling  the  set 
will  be  to  cut  the  shelf  and  panel  to  fit 
the  cabinet.  The  shelf  should  be  cut  so 
as  to  clear  the  cabinet  on  all  sides  by  at 
least  a  half  of  an  inch  when  mounted  on 
the  panel.  It  is  not  absolutely  necessary 
to  have  a  composition  shelf.  A  lami- 
detector-  nated  wood  shelf  will  do  as  well  mechani- 
as  they  cally,  but  if  possible  a  composition  shelf 
is  recommended,  as  it  is  easier  to  work 
and  will  not  warp  as  wood  Will.  Con- 
siderable loss  is  caused  by  the  wood 
absorbing  moisture  during  wet  weather. 

The  next  step  will  be  to  lay  out  and 
drill  the  shelf  and  panel  for  mounting 
the  instruments.  Figure  2  shows  a 
general  arrangement  of  equipment  and 
can  be  followed  with  good  results,  but 
it  is  not  essential,  as  any  good  layout 
will  suffice  if  you  bear  in  mind  to  keep 
the  transformers  placed  so  that  they  will 
not  be  inductively  coupled.  This  is 
accomplished  by  mounting  the  radio 
frequency  transformers  (Rl,  R2,  R3)  on 
an  angle  of  about  45  degrees  or  on 
opposite  planes.  They  should  be  spaced 
at  least  four  inches  apart. 

The  audio  frequency  transformers 
(T  Tl)  should  be  placed  at  right  angles 
to  one  another  and  as  far  apart  and  as  far 
away  from  the  radio  frequency  trans- 
formers as  is  practical.  If  this  is  not 
done,  an  inductive  coupling  effect  will  be 
produced.  The  little  induced  currents 
thus  formed  will  cause  many  annoying 
howls  and  squeals  in  the  receiver. 


When  the  in- 
struments are  all 
placed  in  their 
permanent  posi- 
tions, the  mount- 
ing holes  should  be 
centered  in  the 
panel  and  snelf 
with  a  sharp  in- 
strument. A  nail 
that  has  been  filed 
to  a  good  point  or 
an  awl  will  do  this 
very  nicely. 

Drilling  the 
Holes 

THE  instru- 
-*-  ments  will  then 
be  removed  and 
the  shelf  and  panel 
drilled.  Be  care- 
ful not  to  press  too 
hard  on  the  drill  as 
this  will  cause  the 
edges  of  the  holes 
to  chip. 

It  is  a  good 
practice  to  drill 
the  holes  for  the  condenser  and  rheostat 
shafts  with  plenty  of  clearance.  A  hole 
one-half  inch  in  diameter  is  a  good  size,  as 
it  will  be  a  safeguard  against  the  bind- 
ing of  these  movable  shafts  on  the  panel 
which  would  cause  the  dials  to  turn 
hard  and  make  it  impossible  to  tune  the 
set  critically. 

When  the  panel  is  drilled,  the  front  or 
control  side  should  be  rubbed  with  fine  steel 
wool  (size  000)  until  all  of  the  scratches 
are  removed,  following  this  by  finishing 
off  with  a  fine  piece  of  sand  paper  and 
machine  oil  until  a  dull  velvet  finish  is 
obtained.  The  edges  of  the  panel  should 
be  rounded  off  with  a  fine  file  and 
finished  with  fine  sand  paper  to  prevent 
chipping. 

After  the  shelf  and  panel  are  prepared, 
the  instruments  should  be  mounted  to 
each  and  the  shelf  fastened  to  the  panel 
by  the  brass  brackets  shown  in  figure  5 
as  detail  3.  Brass  machine  screws  and 
nuts  should  be  used  throughout,  as  iron 
screws  will  produce  little  magnetic 
fields  when  near  any  inductance.  These 
little  induced  currents  also  help  to  make 
the  set  noisy. 

When  the  instruments  have  all  been 
mounted  to  the  panel  and  shelf  and  the 
shelf  mounted  to  the  panel,  the  set  will 
be  ready  to  be  wired  or  connected  up, 
but  don't  just  wire  it  or  connect  it  up; 
use  as  much  care  in  doing  this  as  you  have 
in  drilling  the  panel  or  building  the 
transformers,  remembering  that  a  radio  set 
is  only  as  efficient  as  its  most  inefficient 
part.  If  the  wiring  is  not  carefully 
done,  disappointing  results  will  be  ob- 
tained even  though  the  instruments  are 
the  best. 

Many  people,  in  wiring  a  receiving  set, 
make  a  fine  looking  job  of  it  by  arrang- 
ing the  wiring  in  nice  straight  runs  and 
square  corners,  taking  the  longest  way 
around  like  the  bus  work  on  the  switch- 
board in  a  power  station;  but  this  is  a 
very  inefficient  way  to  do  it.    It  must  be 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


13 


"V  XOt/ND  MM 
3XASS    SCB- &  NUTS 

jleft  said  gjjWTW* 


WM 


remembered  that 
the  frequency  o  f 
the  current  pass- 
ing through  the 
wiring  of  a  radio 
set  is  measured  in 
the  thousands  of 
cycles,  while  the 
current  on  the  bus 
work  of  a  power 
switchboard  i  s 
seldom  over  sixty 
cycles. 

The  nice,  long 
parallel  runs  will 
act  as  little  con- 
densers cutting 
down  the  efficien- 
cy of  the  set  by 
increasing  its  in- 
ternal capacity.  It 
is  also  necessary 
that  the  power  or 
low  tension  leads, 
battery  supply 
leads,  and  high 
tension  leads,  grid, 

plate  and  antenna  leads,  be  separated. 
Do  not  run  a  low  tension  lead  parallel 
to  a  high  tension  lead  for  any  distance. 
Keep  the  leads  from  the  input  side  of 
the  tube  (the  grid  leads),  as  short  as 
possible  and  away  from  the  other  leads. 
If  this  interferes  with  another  lead,  make 
the  other  lead  longer. 

Bare  copper  wire  either  No.  12  or  No. 
14  is  heavy  enough  to  care  for  the  cur- 
rents passing  through  a  radio  receiver 
and  will  be  stiff  enough  to  support  them- 
selves when  bent  into  the  required 
shapes.  Solder  all  wire  connections  and 
turn  the  binding  post  and  terminal  nuts 
down  as  tight  as  possible,  as  a  loose  lead 
causes  a  high  resistance  contact  and  is 
sometimes  very  noisy,  especially  if  the 
set  is  subjected  to  much  vibration. 

If  it  is  not  desired  to  use  a  loop  antenna 
or  to  make  the  set  for  the  use  of  both 
the  outside  antenna  and  loop,  the  cutoff 
jack  (X)  and  the  wiring  marked  "X" 
will  be  omitted  and  the  first  radio 
frequency  transformer  (Rl)  connected 
to  the  condenser 
(CI)  as  shown  by 
the  dotted  wiring. 

If  it  is  desired  to 
use  the  loop  an- 
tenna only,  and 
not  arrange  the 
set  for  use  with  an 
outside  antenna, 
the  first  radio  fre- 
quency transform- 
er (Rl)  and  the 
cutoff  jack  (X) 
can  be  omitted 
and  the  two  leads 
from  the  conden- 
ser (CI)  shown 
dotted,  run  to  the 
binding  posts  "A" 
and  "G"  instead 
of  to  the  trans- 
former as  shown. 

The  R.  F.  Trans- 
formers 

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DETAIL  2 


The  dimensions  and  specifications  for  the  radio  frequency  transformers 
are  given  in  the  above  illustration.  The  primary  fits  immediately  inside 
of  the  wall  of  the  secondary  winding  tube,  and  is  held  in  place  with  screws. 


ers,  Rl,  R2,  R3,  six  pieces  of  composition 
tubing  will  be  required,  three  pieces  of 
three  inches  outside  diameter,  three 
inches  long,  and  three  pieces,  two  and 
three  quarters  inches  outside  diameter, 
one  and  one  half  inches  long;  eight  No. 
4  brass  machine  screws  five-eighths  of  an 
inch  long;  thirty  brass  nuts  for  No.  4 
machine  screws  and  about  one-half 
pound  of  No.  26  double  silk  covered 
magnet  wire. 

The  three-inch  tubes  will  hart  five 
holes  drilled  in  each,  to  pass  a  No.  4 
brass  machine  screw.  These  holes  will 
be  one  quarter  of  an  inch  in  from  the 
end  of  the  tube,  as  shown  in  figure  4. 
Two  of  these  holes  will  be  drilled  on  each 
end  of  the  tube  on  opposite  sides  from 
one  another  and  one  midway  between 
the  two  on  the  right  end.  We  will  call 
these  holes  No.  1,  No.  2,  No.  3,  No.  4 
and  No.  5,  as  shown  in  figure  3. 

The  two  and  three-quarter  inch  tubes 
will  have  two  holes  of  the  same  size 
drilled  on  the  left  end  of  each  to  pass  a 


BftASS   BINOiHG 
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SIDE    ELEVATION 


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ELEVATION. 


AfEUT/fAUZ. IN  S        CONDENSER    Sr    SHELF    BRACKET. 


A  Neutrodon  or  Neutralizing  condenser  that  can  be  constructed  at  a 
small  cost,  and  which  has  few  equals  for  efficiency.  This  type  of 
balancing  condenser  can  be  used  to  advantage  on  most  any  type  of 
neutrodyne   receiver   which    requires    the   use    of  a   balancing    element. 


No.  4  brass 
machine  screw, 
these  holes  to  be 
one  quarter  of  an 
inch  in  from  the 
end  of  the  tube 
and  on  opposite 
sides  of  the  tube. 
We  will  call  these 
holes  No.  1  and 
No.  2,  as  shown  in 
figure  3.  They 
should  line  u  p 
with  holes  No.  1 
and  No.  2  on  the 
three-inch  tube 
when  this  tube  is 
placed  inside  of 
the  three-inch 
tube. 

The  tubes  are 
now  ready  to  be 
wound.  We  will 
start  with  the  sec- 
ondary coil  which 
is  to  be  wound  on 
jthe  three-inch 
tube.  Two  small  ho  es  will  be  drilled 
one-half  of  an  inch  in  from  the  left  end 
of  the  tube  and  directly  in  line  with  hole 
No.  1  as  shown  in  figure  No.  4,  to  pass 
and  fasten  the  No.  26  wire.  The  end  of 
the  wire  will  be  passed  down  through 
one  hole  and  up  through  the  other  hole, 
leaving  about  two  inches  of  free  end  for 
connection.  Care  should  be  used  to  see 
that  this  wire  will  lay  close  to  the  inside 
of  the  tube  between  the  two  holes  and 
that  it  is  not  pulled  too  tight,  which 
would  damage  the  insulation  or  break 
the  wire  itself. 

Fifty-five  turns  of  the  No.  26  wire 
will  now  be  wound  in  an  even  layer  on 
the  tube.  This  should  be  wound  on  in  a 
clockwise  direction  when  looking  at  the 
right  end  of  the  tube.  If  the  tube  is 
held  in  the  left  hand  and  the  wire  wound 
so  that  it  goes  away  from  the  body  over 
the  top  of  the  tube  and  toward  the  body 
on  the  lower  side  of  the  tube,  this  will  be 
accomplished.  Two  more  holes  will  then 
be  drilled  directly  in  line  with  the  last 
turn  of  the  coil 
and  opposite  hole 
No.  3  similar  to 
figure  No.  4  and 
the  end  made  fast 
as  was  done  at  the 
start,  leaving 
about  two  inches 
of  free  end  for  con- 
nection. 

The  Winding 

WHEN  the 
three  second- 
ary coils  have  been 
wound,  they  will 
be  laid  aside  and 
the  two  and  three- 
quarter-inch  tubes 
will  have  the  pri- 
mary coils  wound 
on  them ;  two  small 
holes  will  be  drilled 
in  the  right  end  of 
the  tube  opposite 
hole  No.  2  and 
(Turn  to  page  70) 


-Q- 

t 

SHELF    BRACKET     (BAASS) 
DBTfilL    3 


S3 

TfXrtlNAL.- 


t4  RADIO  AGE /or  January,  1925 

Take  Good  Care  of  Your 

HEADPH 


The  Magazine  of  the  Hour 


AFTER  three  years  of  trouble  shoot- 
j\  ing  on  amateur-built  receiving 
-L  \.  sets  I  have  come  to  the  conclusion 
that  "Gyp"  headsets  or  phones  are  as 
much  to  blame  for  failures  as  any  other 
part  of  the  circuit.  It  seems  to  be  a 
common  failing  for  the  builder  to  spend 
money  foolishly  on  all  sorts  of  psuedo- 
refinements  in  the  set  proper  and  then 
to  economize  or  skimp  on  the  phones — 
the  heart  of  the  radio  receiver. 

After  investing  a  hundred  dollars  or  so 
on  nickel-plated  ornaments  and  foolish 
coils,  he  will  go  and  buy  his  phones  from 
the  five  and  ten  cent  counter  and  wonder 
why  he  is  not  getting  the  expected  results 
from  his  set. 

The  importance  of  the  headset  is 
greatly  underestimated  by  the  average 
fan.  He  does  not  seem  to  realize  that 
the  entire  output  of  his  set  is  delivered 
to  the  phones  and  that  whatever  benefit 
he  gets  from  the  set  depends  un  what  the 
phones  are  capable  of  delivering  to  him. 
If  the  efficiency  of  the  phones  is  only  50 
per  cent,  then  he  will  get  only  50  per  cent 
of  the  output  in  the  form  of  sound  waves 
where  he  should  be  getting  a  great  deal 
more.  It  can  be  said  without  exaggera- 
tion that  the  difference  between  a  good 
set  of  phones  and  the  bargain  counter 
type  is  equal  to  two  stages  of  audio 
amplification.  That  is,  the  good  phones 
will  deliver  as  much  volume  from  the 
detector  tube  alone  as  the  poor  phones 
will  deliver  from  the  same  tube  with  two 
stages  of  audio  amplification  added. 
In  fact,  there  are  several  makes  of  phones 
which  will  give  as  much  volume  on  a 
crystal  set  as  a  poor  pair  will  give  on  a 
regenerative  detector  circuit,  and  the 
range  varies  accordingly. 

If  the  radio  novice  paid  as  much  atten- 
tion to  the  selection  of  his  headset  as  to 
the  selection  of  a  hookup  and  the  tuning 
units,  we  would  have  more  consistent 
DX  reception.  When  the  phones  have 
diaphragms  with  the  flexibility  of  cast 
iron  stove  lids,  and  the  magnets  are 
wound  with  hay  wire,  it  is  impossible  to 
make  any  hookup  perform  according  to 
Hoyle.  When  such  poor  magnet  steels 
are  used  for  the  magnets  of  the  phones 


that 
only  a 
faint  trace 
of  magnetic 
flux  remains,  we 
cannot  expect 
to  get  either 
volume  or  sensitivity.  In  addition  to 
these  factors  we  have  the  problem  of 
workmanship  and  adjustment  after 
assembly,  which  are  items  in  the  expense 
of  manufacture  and  which  are  therefore 
often  ignored  even  in  headsets  retailing 
at  a  stiff  price.  Headsets  are  essentially 
a  quantity  production  proposition  and 
can  only  be  made  by  concerns  having 
the  proper  equipment,  and  proper  equip- 
ment means  a  heavy  investment  of  capi- 
tal. Good  headsets  cannot  be  turned 
out  of  basement  shops  by  ex-barbers 
or  old  clothes  dealers.  You  may  rest 
assured  that  when  phones  are  turned  out 
by  hand  in  quantities  of  ten  to  100  pair 
at  a  time,  that  a  good  set  would  cost  in 
the  neighborhood  of  from  $25  to  $50  per 
set. 

Wise  Buying  Advised 

BY  CHEAP  phones  I  do  not  neces- 
sarily mean  phones  that  retail  at 
a  reasonable  price.  Please  do  not  mis- 
understand me.  There  are  firms  that 
turn  out  effective  receivers  at  lists  rang- 
ing from  about  $3.00  to  $4.00  that  are 
comparable  to  cheaply  constructed 
phones  that  retail  at  twice  the  price. 
It  is  easily  possible  by  virtue  of  improved 
tooling  and  minimizing  of  overhead 
expenses  to  turn  out  a  headset  that  will 
retail  at  about  $3.00,  but  only  a  few 
manufacturers  have  such  facilities  avail- 
able. Fortunately,  such  concerns  also 
have  the  money  to  conduct  national 
advertising  campaigns  so  that  the  pur- 
chaser can  feel  fairly  safe  in  buying  a 
low    priced    outfit    when    such    sets    are 


extensively  advertised. 
However,  beware  of  the 
unknown  and  unheralded  cheap 
phone  unless  you  have  means  for  con- 
ducting comparative  tests. 

Next  to  sensitivity  comes  the  item  of 
tone  quality  and  uniform  response  to 
widely  varying  audio  frequencies.  Some 
phones,  while  sensitive,  are  harsh  sound- 
ing and  give  unnatural  reproduction,  due 
principally  to  the  construction  of  the 
diaphragms  and  the  arrangement  of  the 
pole  pieces.  Further,  in  a  double  head- 
set -  both  phones  should  be  perfectly 
matched,  so  that  they  give  perfectly 
uniform  volume  and  tone.  Headsets, 
while  apparently  the  most  simple  device 
in  the  receiving  outfit,  are  the  most 
difficult  to  construct.  A  good  pair  of 
phones  will  give  a  smooth,  soft  reproduc- 
tion with  almost  perfectly  uniform  accent 
on  high  and  low  pitched  notes.  They 
are  as  responsive  to  the  low  shuddering 
notes  of  the  pipe  organ  as  to  the  high 
upper  notes  of  the  soprano.  Poorly 
constructed  phones  are  generally  insen- 
sitive to  the  lower  pitched  notes  and 
unduly  sensitive  to  high  pitches,  thus 
giving  an  unbalanced  reception. 

With  improper  diaphragms  and  mag- 
nets, it  is  possible  to  lose  half  of  the 
orchestra  because  of  the  selectivity  of 
the  diaphragms.  Very  sensitive  phones 
with  exceedingly  thin  diaphragms  gen- 
erally have  a  lower  natural  period  than 
insensitive  phones,  and  while  they  record 
low  notes  with  accuracy,  they  will  buzz 
and  rattle  on  high  notes.  By  combina- 
tion of  thin  diaphragms  with  proper 
"damping"  we  gain  a  better  distribution 
of  sound. 

Elements  of  the  Phones 

EVERY  headset  consists  of  the  follow- 
ing elements  in  some  form  or  other: 
1)  The  thin  diaphragm  which  is 
made  of  either  sheet  steel  or  mica,  and 
which  vibrates  at  voice  frequency 
under  the  influence  of  the  audio  fre- 
quency currents.  (Turn  to  page  57) 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour  15 


A  6-TUBE 
SUPER-E 


By  PAUL  GREEN 


A  Wonder  Circuit  That  Can  Be  Built  for 
Approximately  $55! — Compares  Favorably 
With  Larger  Supers;  Uses  Simple  Control 


MANY  a  fan  has  been  waiting  for  a 
super-heterodyne  that  could  be 
built  for  little,  if  any,  additional 
cost  over  what  a  neutrodyne  or  other 
similar  set  would  cost.  Here  is  one  that 
can  be  built  for  approximately  $55.00  and 
that  will  give  you  results  that  will  stack 
up  well  with  larger  editions  of  the  same 
circuit. 

In  fact,  this  circuit  is  practically  the 
same  circuit  as  heretofore  described  by 
the  writer  in  RADIO  AGE,  but  with 
one  stage  of  audio  and  one  stage  of  inter- 
mediate    omitted. 

In  building  this  set,  the  purpose  that 
the  writer  had  in  mind  was  to  provide 
something  that  would  be  inexpensive 
and  yet  woud  produce  results  such  as 
the  average  fan  .desires.  All  the  parts 
used  are  standard,  so  there  will  be  no 
difficulty  in  securing  them. 

One  unique  feature  of  this  circuit  lies 
in  the  fact  that  it  uses  only  one  filament 
control. 

Great  pains  have  been  taken  in  laying 
out  the  circuit  so  as  to  utilize  the  base- 
board and  panel  space  to  very  best  ad- 
vantage. There  is  not  one  inch  of  sur- 
plus space,  so  it  will  be  necessary  to 
follow  instructions  very  carefully  in 
building  yours.  It  will  be  further  noted 
that  this  arrangement  provides  for 
exceptionally  short  grid  and  plate  leads. 
An   examination   of  the  underside  of  the 


Pictures  by  the  Author 

baseboard  will  show  how  the  balance  of 
the  wiring  is  disposed  of. 

"Balancing  Out  the  Loop" 

UNKNOWN  probably  to  most  radio 
enthusiasts,  regeneraton  plays  an 
exceedingly  important  part  in  securing 
selectivity  as  well  as  volume  and  dis- 
tance. If  regeneration  is  pushed  too  far, 
the  circuit  is  said  to  slop  over  or  become 
mushy.  Resistance  is  one  of  the  factors 
which  stands  in  the  way  of  selectivity  and 
volume.  Regeneration,  if  properly  used, 
tends  to  break  down  this  resistance  and 
thereby  gives  us  the  selectivity  desired. 
The  use  of  regeneration  in  this  circuit  is 
unique,  and  must  be  fully  appreciated  to 
get  best  results. 

An  examination  of  the  diagram  will 
show  that  a  midget  condenser  is  so  con- 
nected that  its  rotor  plates  are  next  to 
the  plate  post  of  the  first  intermediate 
transformer  and  the  first  detector  tube. 
The  stator  plates  are  connected  to  the 
one  side  of  the  loop  in  common  with  the 
rotor  plate  of  the  loop  condenser.  By 
adjusting  this  condenser  to  the  proper 
value,  regeneration  of  exactly  the  right 
degree  can  be  obtained.  Too  much 
regeneration,  as  above  stated,  will -ruin 
reception.  Too  little  regeneration  will 
prevent  the  set  bringing  in  its  full  quota 


of  distant  stations.  Too  much  cannot  be 
said  regarding  this  portion  of  the  circuit. 
You  will  find  many  fans  will  tell  you 
that  this  small  condenser  can  be  dis- 
pensed with.  Pay  no  attention  to  them. 
The  condenser  for  this  purpose  should 
contain  nine  plates  and  should  be  of  a 
panel  mounting  variety.  If  upon  test- 
ing your  set,  you  find  that  you  can- 
not place  the  plates  far  enough  apart  to 
prevent  over-regeneration,  remove  one 
plate  at  a  time  until  the  proper  capacity 
has  been  reached. 

The  Variable  Condenser 

T^HESE  two  condensers  have  been 
-*-  found  by  experiment  to  be  well  adapt- 
ed to  this  circuit;  however,  there  are 
plenty  of  other  good  low  loss  types  on  the 
market.  The  only  point  to  be  borne  in 
mind,  if  you  desire  to  use  other  low  loss 
condensers,  is  that  it  is  preferable  that 
they  be  not  only  low  loss  but  straight 
line  condensers  as  well.  The  importance 
of  this  suggestion  will  be  realized  when 
you  make  your  first  set  of  loggings. 
There  will  be  plenty  of  separation 
between  the  upper  and  the  lower  oscilla- 
tor dial  settings  on  stations  around  500 
meters,  but  when  you  get  down  to  sta- 
tions of  about  250  meters,  you  will  find 
that  the  settings  come  much  closer 
together. 

With  straight-line  condensers  the  set- 
tings are  farther  apart  around  250  meters 


16 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


A  top  view  of  the  Baby  Grand  super-heterodyne  receiver  described  by  Mr.  Green  in  the  ac- 
companying article.    This  layout  must  be  religiously  adhered  to  if  results  are  to  be  expected. 


Oscillator  Coupling 

The  oscillator  is  the 
device  which  shows  on 
the  extreme  right  hand 
end  of  the  baseboard  as 
you  look  at  the  illustra- 
tion. Too  tight  coup- 
ling of  these  coils  will 
usually  result  in  less 
selectivity  and  less  vol- 
ume. ,  For  distance  re- 
ception, avoid  too  tight 
a  coupling  at  all  times. 
There  are  several  types 
of  oscillator  coupler  on 
the  market.  The  writer 
would  be  glad  to  give 
anyone  interested  full 
constructional  details  for 
the  making  of  a  very 
efficient  home-m  a  d  e 
coupler  at  little  expense 
if  you  will  address  him 
care  of  RADIO  AGE. 

While  speaking  o  f 
home-made  apparatus, 
it  might  be  well  to 
mention  the  output  coil. 
The  one  shown  is  wound 
on  a  bobbin  two  inches 
in  diameter  with  a  one 
inch  core.  The  winding 
space  is  1-2  inch  wide. 
The  primary  consists  of 
200  turns  of  No.  28 
single  cotton  or  silk 
covered  wire,  over  which 
the  secondary  is  wound 
with  no  other  separation 
than  the  natural  insula- 
tion of  the  wire.  The 
secondary  consists  of 
1,500  turns  of  No.  36 
silk  or  cotton  covered 
wire.  The  bobbin  for 
this  output  transformer 
can  be  turned  out  of 
kiln-dried  wood  or  per- 
haps more  conveniently 


than  is  the  case  with  the  ordinary  type 
of  condenser.  Not  only  that,  but  with 
straight-line  condensers,  it  is  much 
easier  for  you  to  lay  out  your  graph  and 
to  predict  with  almost  uncanny  certainty 
the  dial  settings  of  any  station  for  which 
you  have  the  wavelength.  With  the  dials 
properly  adjusted,  they  should  tune 
almost  exactly  alike,  especially  on  sta- 
tions around  300  meters.  This,  of 
course,  refers  to  the  upper  oscillator  dial 
setting  and  the  normal  loop  setting.  It 
will  be  found  that  there  are  two  settings 
for  each  station  on  the  oscillator  dial. 
This  is  as  it  should  be,  so  don't  be 
worried. 

It  might  be  added  that  the  two  settings 
are  a  decided  advantage  because  of  the 
fact  that  this  allows  you  to  utilize  the 
setting  which  is  farthest  from  the  source 
of  interference.  You  will  hear  many 
persons  dispute  this,  but  don't  let  that 
bother  you.  The  rheostat  will  usually  be 
found  to  have  one  setting  at  which  the 
circuit  functions  best.  Referring  again 
to  the  small  condenser  used  for  controll- 
ing loop  feed-back,  it  should  be  men- 
tioned that  very  little  coupling  is  neces- 
sary; usually,  not  more  than  1-10  or  1-15 
of  the  way  in. 


1 8 


Bottom  V/'ew-  Jb&sehoQrd 

(.Pkasilcrrx)    >i,  Scale   , 
K '7'  


This  gives  you  an  idea  of  what  is  meant  by  good  design 
and  engineering.     The  bottom  view  of  the  Baby  Grand. 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


17 


made  up  of  two 
pieces  of  bakelite 
2  "x2  "  x  3-16"  for 
the  sides  and  a 
1-2 "  section  of  1 
inch  diameter 
bakelite  or  wood 
rod  for  the  core.  A 
brass  screw  of  any 
convenient  dimen- 
sion and  approxi- 
mately two  inches 
in  length  should 
be  passed  through 
the  center  of  this 
bobbin.  This  screw 
will  serve  as  a  con- 
venient means  of 
holding  the  bob- 
bin core,  while  at 
the  same  time  en- 
abling  you  to 
chuck  the  coil  in  a 
lathe  or  hand  drill    for  winding. 

If  you  use  your  hand  drill  for  winding, 
merely  turn  the  handle  of  the  drill  as 
many  times  for  the  primary  and  second- 
ary respectively  as  the  ratio  of  your  drill 
is  contained  into  the  number  of  turns 
required.  Thus,  if  the  ratio  of  your  drill 
is  5  to  1,  you  will  only  need  to  turn  the 
handle  of  your  drill  40  times  when  put- 
ting on  the  primary  and  300  times 
when  putting  on  the  secondary. 

If  any  of  the  readers  of  this  article 
would  like  to  have  more  detailed  descrip- 
tion of  the  construction  of  this  simple 
output  tuner,  these  details  will  be  sup- 
plied in  the  same  manner  as  those  of  the 
oscillator    coil. 

Baseboard 

TT  GOES  without  saying  that  inasmuch 
-*-  as  a  large  part  of  the  wiring  is  done 
beneath  the  baseboard,  the  baseboard 
should  be  of  bake- 
lite or  hard  rub- 
ber. It  can  be 
fastened  to  the 
front  panel  by 
means  of  brass 
brackets  or  angle 
pieces  not  shown 
in  the  illustration. 
If  the  set  is  to  be 
handled  much  be- 
fore it  is  put  into 
a  cabinet,  it  will 
be  well  to  put  long, 
diagonal  brackets 
from  the  top  of 
the  front  panel  to 
the  back  of  the 
baseboard.  B  y 
doing  most  of  the 
wiring  beneath  the 
baseboard,  it  is 
possible  to  make 
the  grid  and  plate 
leads  exceptional- 
ly short,  which,  as 
you  know,  is  a 
very  important 
feature.  The  long- 
est leads  for  the 
set  are  "a"  battery 
leads  and  these 
are  comparatively 
short,      For    con- 


Two  controls  that  require  only  two  hands  to  tune  with.  The  filament  rheostat  may  be 
set  and  left  there,  and  while  the  regeneration  requires  an  occasional  touch  when  tuning  on 
widely  separated  wavelengths,  it  is  not  troublesome.  The  filament  switch  on  the  right 
permits  one  to  turn  off  the  set  while  lashing  the  phones  or  loud  speaker  to  the  table  when 
strong  signals  are  to  be  received. 


venience  in  placing  this  set  in  a  cabinet 
the  writer  extended  the  binding  post 
back  of  the  baseboard  an  inch  and  a 
quarter.  This  permits  of  reaching  the 
binding  posts  from  the  outside  of  the 
cabinet,  without  raising  the  lid.  It  will 
merely  be  necessary  to  cut  a  slot  in  the 
back  of  the  cabinet  long  enough  and  high 
enough  to  allow  the  binding  post  bracket 


expense  of  the  set 
is  thus  kept  down 
to  a  point  very 
little,  if  any,  in 
excess  of  that  of 
any  ordinary  set. 

All  of  the  parts 
chosen  in  this  cir- 
cuit were  deliber- 
ately chosen  be- 
cause of  their 
known  ability  to 
perform  properly. 
While  undoubted- 
ly there  are  other 
pieces  of  apparatus 
that  might  be  sub- 
stituted, yet  it  is 
suggested  that 
when  you  build 
your  set  you  ad- 
here to  the  sugges- 
tions as  to  the 
parts  to  be  used.  Otherwise,  it  will  be 
next  to  impossible  to  analyze  your 
troubles  or  to  correct  them. 

This  little  "Baby  Grand"  superhetro- 
dyne  is  the  outcome  of  a  great  deal  of 
experimentation  and  as  it  performs  just  as 
a  super-heterodyne  should  perform,  you 
will  gain  nothing  by  trying  to  substitute 
parts.       This    point    can    be    very    well 


to  slip  through,  after  which  the  binding    understood  when  it  is  explained  that  the 
posts  and  their  screws  can  be  placed  in    intermediate    transformers    used    are   in- 
tended   to    peak   at    a   given    frequency. 
The  output  coil  is  tuned  to  peak  at  the 
same     frequency.       Any     changes     that 


position. 

Transformers 

The  two   transformers   shown 


on   the 

center  portion  of  the  baseboard  are  so- 
called  long  wave  transformers.  Only  one 
step  of  audio  is  used  in  this  circuit,  so  that 
from  the  standpoint  of  expense  very 
little  money  is  spent  for  transformers. 
This  point  alone  makes  this  circuit  ideal 
for   the    average    radio    fan.      The   total 


The  business  end  of  the  powerful  little  superheterodyne  receiver  described  by  Mr. 
Green.     It  gives  one  an  idea  of  what  a  compact  efficient  super-het  should  look  like. 


might  be  made  in  apparatus  are  almost 
certain  to  cause  trouble  because  of  the 
inability  of  substituted  apparatus  to 
function  best  at  the  frequency  for  which 
this  set  was  designed. 

HPHERE  is  nothing  to  fear  in  the  wiring 
*■  of  this  circuit.     Follow  the  two  base- 
board   layouts 

closely   and    place 

your  apparatus  as 
shown.  The  dis- 
tance between  the 
oscillator  conden- 
ser and  the  loop 
condenser  has  been 
carefully  de- 
termined after 
quite  a  bit  of  ex- 
perimentation. If 
you  change  the 
spacing,  it  is  quite 
likely  that  the  set 
will  not  function 
as  it  should  and 
you  will  find  it 
necessary  to  make 
minor  adj  ustments 
to  compensate. 
This  will  involve 
experimentation, 
which  it  is  the  pur- 
pose of  this  article 
to  eliminate. 

As  stated,  prac- 
tically all  of  the 
wiring  is  done  be- 
neath the  base- 
board. There  are 
a  number  of  ad- 
vantages to  this 
(Turn  to  page  66) 


18 


«L 


RADIO  AGE  for  January,  1925 

An  Unusual  Account 
of  The  Development 
of  A  Simple  Tube  Set 


The  Magazine  of  the  Hour 


IF  YOU  are  interested  in  the  crystal 
detector,  previously  described,  and 
want  to  experiment  further  with 
crystals,  you  will  prefer  the  circuit  shown 
in  Hook-up  No.  2.  This  is  No.  2,  the 
Long-distance    Hook-up. 

While  we  do  not  recommend  it  as 
giving  the  general  satisfaction  of  Hook- 
up No.  1,  it  has  often  been  reported 
giving  phenomenal  distance.  Try  it 
as  you  would  a  grab-bag — you  may 
get   a   prize! 


HOOKUP  NO  TWO 

LONCr  DISTANCE  CQyJTAL 
\l/  CG'/SrAL 

DFrecroe 
►<}- 


The  feature  of  this  circuit,  of  course, 
must  be  efficiency.  A  sturdy  low-loss 
variometer  (with  two  stagger-wound 
coils  giving  a  perfect  ratio  of  inductance) 
is  recommended  to  insure  conserving 
all   the   precious  signal  energy. 

Vacuum  Tube  as  a  Detector 

WHILE  the  crystal  yields  a  wonder- 
fully true  tone  and  while  your 
knowledge  of  it  will  prove  valuable  in 
some  interesting  combination  hook-ups 
later,  you  must  depend  upon  the  vacuum 
tube  to  secure  distances  of  over  twenty 
to  fifty  miles. 

The  vacuum  tube  is  simply  an  elec- 
trical "valve."  It  enables  a  minute 
quantity  of  electricity  caught  by  the 
antenna  to  turn  on  and  off  a  powerful 
current  (the  B-battery  current).  This 
B-current  operates  the  phones.  The 
action  of  the  tube  is  like  that  of  a  child 
turning  a  faucet  on  and  off  and  con- 
trolling a  great  current  of  water.  Or  it 
is  like  the  delicate  fingers  of  the  musician 
manipulating  the  key-controls  of  an 
organ,  releasing  the  power  which  produces 
great  sounds. 

The  accompanying  drawing  shows  the 
three  elements  of  the  vacuum  tube. 

The  filament  when  heated  to  incan- 
descence by  an  "A-battery"   (usually  of 


about  6  volts)  throws 
off  small  electrical 
particles  or  electrons. 

The  powerful  cur- 
rent (from  the  B- 
battery)  which  op- 
erates the  phones 
travels  from  the  fila- 
ment "on  the  back" 
of  these  electrons  to 
the  plate. 

The  grid,  however, 
is  between  the  fil- 
ament and  plate.  It 
acquires  an  elec- 
trical charge  caught 
by  the  an  tenna. 
These  charges  on  the 
grid  either  repel  or 
attract  the  electrons  from  the  filament 
and  thus  weaken  or  strengthen  the  value 
of  the  B-current. 

Also  the  tube,  like  the  crystal  detector, 
is  a  rectifier,  permitting  current  to  flow 
in  one  direction  only.  This  gives 
pulsating  direct  current,  a  necessity  for 
the  operation  of  the  'phones. 

First  Tube  Hook-up 
"V^OU  are  now  prepared  to  follow  in  the 
-*-  footsteps  of  the  masters  of  radio  with 
one  of  the  first   and    most  famous  of 


T/ieALLADIN'S 


And  How 

By  EDMUND 


circuits,  the  "Ultra- Audion."  This  cir- 
cuit is  extremely  easy  to  build  and 
operate,  and  is  capable  of  excellent  long 
distance  reception.  The  parts  here  listed 
will  not  cost  much. 

1.  Ultra-Audion  coil.  You  must  use 
an  efficient  coil  with  four  taps  for  this 
purpose. 

2.  Switch  lever  and  four  switch  points. 

3.  Grid  leak  and  grid  condenser.  See 
Vacuum  Tube  Chart  to  be  published  in 
our  February  Beginners'  Section.  We 
recommend  U.  V-199  or  C.-299  tubes  and 
dry  cells  for  this  circuit.  It  is  important  to 
buy  a  good  accurate  grid  leak.  The  two  de- 
vices may  be  obtained  combined  and 
certified  as  to  accuracy  and  must  be 
chosen  wisely. 

4.  Socket  to  fit  tube  selected. 

5.  One  variable  condenser  (with  dial) 
capacity  .0005  microfarads,  vernier  and 
low-loss  type  preferred. 

If  a  condenser  with  bakelite  end-plates 


is  used,  a  shield  of  aluminum  or  zinc  must 
be  placed  between  it  and  the  panel. 

6.  One  rheostat  to  match  tube  se- 
lected. 

7.  Head-set  of  good  quality. 

8.  One  vacuum  tube;  U.  V.  199  or 
C.  299  recommended. 

9.  "A"  battery  selected  according  to 
type  of  tube  you  want  to  use. 

10.  One  "B"  battery  of  22  1-2  volts 
of  well  known  brand.  A  tapped  type 
should  be  used  with  U.  V.  200  or  C.  300 
tubes. 

11.  Necessary  connecting  wire,  an- 
tenna wire,  and  insulators. 

12.  No  recommendations  as  to  panel 
or  cabinet  size,  as  you  may  wish  to  add  a 
two-step  amplifier  to  the  set  after  you 
see  how  the  set  works.  The  illustration 
shows  a  panel  6  by  7  inches.  You  must 
secure  a  drill  for  drilling  iron,  and  will  not 
find  it  difficult  then  to  bore  holes  in  the 
rubber  or  bakelite  panel. 


SYMBOLS 


USBD     IN 
1 

T 


-41 


A  BATdQV 
?OQ  FiLA  - 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


19 


<L 


The  Operation  of  the 
VacuwnTube  asDetector 
Explained  for  Beginners 


Lamp  of  RADIO 


to  Use  It 

H.  EI  TEL 


HPO  learn  the  Ultra-Audion  circuit, 
-*-  experiment  with  it.  On  these  pages 
is  given  the  "Improved  Ultra-Audion;" 
Hook-up,  No.  4.  Its  chief  advantage  lies 
in  better  control  of  the  feed-back  of  cur- 
rent from  the  plate  circuit. 

You  must  observe  that  one  reason  for 
the  effectiveness  of  this  circuit  is  that  the 
signal  is  amplified  in  passing  through  the 
tube  and  is  returned  to  the  antenna  circuit 
and  thus  strengthens  the  original  and 
controlling   signal. 

By  using  a  variometer  instead  of  a 
fixed  coil,  you  can  control  this  feed-back 
and  so  secure  better  efficiency  or  farther 
distance  reception.  The  only  change  in 
your  apparatus  needed  is  the  addition 
of  the  variometer.  We  advise  that  a  good 
low-loss  type  be  used. 

Gibbon's  Ultra-Audion 

The  experimenter  may  now  add  a 
variable  grid  leak  between  the  grid  and 


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the  filament  as 
shown,  and  have  the 
Gibbon's  Hook-up. 
This  is  the  last 
word  in  the  Ultra- 
Audion.  Its  success 
depends  upon  a  su- 
premely fine  variable 
grid  leak  which  is 
not  difficult  to  find. 
We  recommend  that 
Hook-ups  No.  3  and 
No.  4  be  made  first, 
however. 

In  operating  any 
of  the  circuits  illus- 
trated, it  is  always 
wise  t  o  remember 
that  the  filament  con- 
trol is  one  of  the  important  knobs  on  the 
set,  and  the  best  results  are  only  obtained 
with  the  proper  filament  current  value. 
Since  this  feature  of  the  circuit  is  rather 
critical,  it  is  advisable,  of  course,  to  pro- 
vide for  delicate  changes  in  filament  con- 
trol, and  a  vernier  rheostat  of  either  the 
carbon  pile  or  metal-dust-carbon  should 
be  used. 


HOOKUP  NO  FOUp 

37Z>A.fv-frr  UCT7?A-AuDiOA/  V5WG- 
*Gt2/AL       ^n     *AJ?lO*nE-T&R  -  &AD/A7ES 


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Have  Tubes  Tested 

When  you  make  a  purchase  of  a  tube, 
remember  that  the  safest  way  is  to  cater 
to  a  dealer  who  has  a  testing  device  that 
will  give  the  characteristics  for  the  tube 
you  intend  to  purchase.  Nearly  every 
large  dealer  in  tubes  has  at  his  disposal  a 
"testometer"  for  this  purpose,  and  can 
give  his  patrons  absolute  satisfaction  in 
giving  them  the  proper  type  of  tube  for 
their  use. 

When  buying  tubes,  the  general  test 
is  to  see  if  the  filament  lights;  if  it  does,  it 
is  assumed  that  the  tube  is  satisfactory 
for  all  purposes.  This,  unfortunately,  is 
not  the  case,  since  there  are  tubes  that 
are  defective  internally  or  their  charac- 
teristics may  make  them  better  amplifiers 
than  detectors,  or  they  may  be  "duds." 
The  common  term  for  a  tube  that  re- 
fuses to  oscillate  is  "dud."  So  when  buy- 
ing, specify  what  your  tube  is  going  to  be 
used  for,  and  have  your  dealer  pick  one 
out  of  stock  that  which  is  suited  to  your 
needs. 


TT  might  be  well  to  mention  that  ex- 
*-  treme  care  should  be  exercised  in 
tuning  the  receivers  illustrated  herewith, 
as  they  are  especially  violent  squealers 
when  mishandled.  This  circuit  is  bas- 
ically the  Colpitts  transmitting  circuit, 
and  if  hard  tubes  are  used  with  plenty  of 
B  battery  voltage,  you  may  do  terrible 
things  to  your  next  door  neighbor's  re- 


tiOQKUP  HO  f*/V£ 

S/MPLF  (r/BBaHS  OCT/?A  -AUD/O/V 
USE  LOW  LOSS  APPA&A  rus 
AeeiAL         W   CMuW.  GAD/ATES 


ceiving  if  you  are  not  careful.      By  all 
means,  do  not  let  the  set  squeal. 

Tuning  Simple 

The  tuning  is  very  simple.  For  any  of 
the  circuits  shown,  about  the  same  pro- 
cedure is  followed.  The  filament  is 
turned  on  till  the  tube  reaches  the  critical 
point,  which  is  just  immediately  below 
the  thump,  indicating  oscillation  and 
squeals  which  are  heard  as  the  filament  is 
advanced. 

With  the  filament  set  at  this  point,  the 
taps  or  variometer  is  varied  together  with 
the  variable  condenser  knob  until  a  signal 
is  heard.  Adjustments  are  then  made 
until  the  signal  is  clearest  and  loudest. 

In  an  accompanying  illustration,  we 
are  printing  for  the  benefit  of  those  un- 
initiated, the  common  symbols  used  in 
connection  with  vacuum  tube  diagrams. 
Simple  comparisons  between  the  dia- 
grams shown  elsewhere  on  the  page  and 
with  the  chart  is  in  itself  a  little  lesson  in 
reading  diagrams.  Once  the  reader 
memorizes  the  symbols,  it  becomes  quite 
an  easy  matter  for  him  to  read  them  and 
compare  circuits. 

In  reading  circuits,  always  remember 
that  the  positions  of  the  symbols  on  the 
chart  have  no  bearing  mechanically  on 
the  layout  or  assembly  of  the  receiver  as 
a  whole.  The  purpose  of  the  diagram  is 
to  furnish  a  set  of  electrical  connections 
for  the  various  units  of  the  receiver 

We  do  find  mechanical  specifications 
inferred  on  diagrams  when  small,  light 
pointed  arrows  are  drawn  across  induc- 
tances, resistance  or  capacities  to  indicate 
that  they  are  variable,  in  which  case  they 
are  usually  controlled  from  the  front  of 
the  panel. 

For  the  purpose  of  giving  more  infor- 
mation on  this  subject,  we  would  refer 
you  to  the  RADIO  AGE  ANNUAL  for 
1924. 


20 


RADIO  AGE  for  January,  1925 


What  the  Broadcasters  are  Doiri'> 


Tuning  In  with  the  French  Fan 


C.How  French  Equipment 

Differs  from  U.  S. 

Sets  and 

Parts 

PARIS: — Radio  reception  is  now  very 
popular  in  France;  there  is  not  one 
small  village  which  cannot  boost 
itself  as  having  a  score  of  radio  listeners. 
The  programs  are  very  up-to-date 
and  the  ears  of  the  countrymen  are 
astonished  by  the  ragtimes  and  jazz 
music  imported  from  across  the  pond. 
Great  was  my  surprise  when  I  first 
listened  to  a  radio  concert,  in  hearing 
"Gallagher  and  Shean"  and  "Dream 
Daddy." 

I  thought  my  friend  had  succeeded  in 
getting  an  American  station  and  I  was 
going  to  congratulate  him,  when  the}' 
announced  in  true  Parisian  French, 
"Vous  allez  maintenant  entendre. 
(You  will  now  listen  to     .     .     .)" 

How  Sets  Differ 

rT,HE  purpose  of  this  article  being  to 
show  the  main  differences  between 
the  American  and  French  radio  equip- 
ment, we  will  start  by  describing  the 
aerial  and  ground,  the  set  itself,  the 
radio  parts  and  novelties. 

The  first  thing  to  consider  is  what 
stations  may  be  heard,  what  kind  of 
program  and  entertainment  they  have, 
and  especially  what  their  wavelength  is. 
The  aim  of  the  radio  fan  is  to  hear  as 
many  stations  as  possible,  enabling  him- 
self to  pick  out  the  best  programs  and 
be  entertained  at  any  hour  of  the  day. 

Unfortunately,  the  number  of  Euro- 
pean broadcasting  stations  is  far  from 
being  as  considerable  as  it  is  in  America; 
a  dozen  or  so  in  England,  five  or  six  in 
France,  a  few  in  Ger- 
many, Italy  and  Spain. 

To  make  matters 
worse,  these  stations  are 
far  from  working  in  a 
small  range  of  wave- 
lengths; the  English  are 
between  300  and  500 
meters;so  aresomeofthe 
French  stations;  but  the 
Eiffel  tower  FL  works  on 
2600,  Radio-Paris  SFR 
on  1780,  Madrid  EGC  on 
2  2  00,  Koenigswuster- 
hausen  on  6000.  There  is, 
of  course,  no  danger  of 
interference  but  the  re- 
ceiving set  has  to  be  de- 
signed to  cover  all  the 
wavelengths. 

The  Aerials 


By  C.  R.  Bluzat 


jflw 

1  ^jyjySa 

|p|»ftiii^v      flv 

Above  is  a  loud  speaker  of  artistic 
design  recently  introduced  in  France. 
The  diaphragm  transmits  its  vibra- 
tion to  a  pleated  parchment  disc, 
giving     pure,     unadulterated      tone. 

sists  usually  of  two  units  of  six  turns  on 
a  four  to  six  foot  square  frame,  provision 
being  made  to  use  them  in  series  (long 
waves)  or  in  parallel  (short  waves). 

A  new  type,  just  put  on  the  market, 
consists  of  a  flat  copper  strip  12  meters 
long  (app.  36  feet).  This  ribbon  is . 
usually  strung  around  a  room,  so  that 
its  wider  surface  is  parallel  to  the  earth. 
It  is  claimed  that  the  ribbon  acts  like  a 
plate  of  a  condenser,  the  other  plate 
being  the  earth  itself.  Far  better  results 
have  been  obtained  than  with  a  loop 
of  same  length,  due  to  this  capacity  effect. 


^Frenchman's  Set  Has  to 

Be  Designed  to 

Cover  Varied 

Waves 

three   square   feet   laid   on   or   imbedded 
in  the  earth  at  one  foot  depth. 

Receiving  set. — Due  to  the  broad 
range  of  wavelengths,  the  maximum 
inductances  of  the  primary  and  secondary 
circuits  have  to  be  rather  large;  they 
consist  of  a  certain  number  of  units 
which  may  be  cut  in  or  out  through 
appropriate  switches.  Condensers  of 
.0005  or  .001  microfarad  may  be  put 
in  series  or  in  parallel  with  the  antenna 
inductances.  Use  is  also  made  of  honey- 
comb or  spiderweb  coils,  a  set  being  used 
for  short  wave,  another  for  long  wave 
reception. 

A  great  number  of  listeners  are  still 
using  crystal  sets,  some  built  with  slid- 
ing contact  coils  of  pre-war  fame;  but 
the  tube  set  is  superseding  the  crystal, 
especially  since  the  appearance  on  the 
market  of  the  so-called  "micro"  lamp 
which  is  of  low  current  consumption 
like  the  American  UV-201A  or  UV  199. 
Radio  frequency  amplification  as  well 
as  audio  frequency  amplification  are  a 
feature  of  any  good  set.  For  the  first 
type  of  amplification,  the  manufacturer 
of  transformers  had  to  meet  very  strict 
requirements.  In  America,  where  the 
wavelength  range  is  only  from  250  to 
600  meters,  we  know  it  has  been  a  real 
job  to  realize  a  transformer  which  would 
keep  its  amplification  factor  about  the 
same  all  over  the  broadcasting  wave- 
lengths. 

The  French  manufacturer  had  to  de- 
sign a  transformer  which  would  amplify 
satisfactorily  from  300  to  4000  meters. 
Success  has  been 
achieved,  and  some  trans- 
formers cover  now  from 
150  to  12000  meters  with- 
out any  tap!  Regenera- 
tive sets  are  predominant 
now;  Reinartz  finds  great 
favor  for  the  short  wave 
reception.  Super-regen- 
eration is  tried  by  a  few 
"dyed-in-the-wool"  fans, 
Flewelling  having  be-, 
come  a  favorite  lately. 
Super-heterodyne  sets 
are  the  favorites  for 
transoceanic  reception. 

Their  Parts 


A  typical  French  receiving  set,  with  its  "micro"  lamps, 
or  tubes,  on  the  outside.  So  objectionable  has  this  type  become, 
with  its  brilliant  glare  and  unsightly  appearance,  that  theFrench 
are  slowly  adopting  the  American  design  of  radio  set  cabinet. 


The  antenna  constants 
must  be  larger  than  in  America.  The  aerial 
may  consist  of  only  one  wire  of  90  to  150 
feet;  preference  is,  however,  given  to  a 
high  capacity  type  such  as  a  three  or  four 
wire  antenna  or  a  cage  antenna  strung  as 
high  as  possible.  The  inside  aerial  is 
being  used  more  and  more;  the  loop  con- 


The  Ground 

TN  THE  towns  the  ground  connection 
-*•  is  made  to  the  water  system;  in  the 
country,  special  galvanized  iron  rods 
three  feet  long  are  forced  into  the  earth, 
in  a  wet  place  if  possible.  They  also 
use  copper  plates  or*  netting  of  two   to 


Parts  differ  from  the 
American  standard  by 
mechanical  construction. 
The  variable  condensers 
come  in  .00025,  .0005, 
.001  and  .002  microfarad.  The  vernier 
attachment  consists  of  a  brass  rod  with  a 
long  detachable  knob,  the  back  end  being 
shaped  like  a  small  grooved  pulley.  A 
large  bakelite  disc  fastened  to  the  moving 
plates  shaft  engages  in  this  groove  and  is 
(Turn  to  page  61) 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


21 


"Juggling"  Your  Circuit  for 

An  Efficient   PORTABLE   SET 


I 


portable  in  the  strictest  sense  of  the  word 

and    which    contains    every    last     item     j\J  Q      QUtslde     WireS 

necessary  to  its  functioning. 


T  GOES  almost  without  saying  that  By    BRAIN ARD    FOOTE  s° '°ng  as  the  R.  F.  transformers  weren't 

the  ambition  of  every  radio  fan  and  •'              '  closer   than   an   inch  or  so.     The  audio 

experimenter  is   to   possess   a   com-  "  transformers  were  likewise  changed  about 

plete   receiving   set   which   will   work  in  J—f  p  f  p     o     rt      f?  p  r  p  j  71  p  f  and  interchanged  with  those  of  different 

any  location,   at  any  time,   without  the  makes  and  varying  ratios  and   the  only 

slightest  wire  connection  to  aerial,  bat-  'in  fit    W/  I  1 1     F*1  J  fl  ft  \ Vlfl  perceptible    difference   in   operation   was 

teries   or   anything    else   outside   of   the  i    'IWl     W  IH    i     U/tHH/fl  that  transformers  of  higher  ratio  (larger 

outfit.     In  other  words,  it's  a  set  that  is  A  i     p 71  p  f\j     J    r\r fit j nn   •  secondary  windings)  required  larger  by- 

■_  y  Z_Z.. '  pass    condensers. 

The  Hook-up 

T^HE  circuit  diagram  reveals  a  straight 
•*-  reflex  amplifier  circuit,  reception 
being  accomplished  with  a  loop  and  one 
variable  condenser.  The  three  tubes 
1,  2  and  3  amplify  successively  at  radio 
frequencies  whatever  signal  is  tuned  in 
and  passed  to  the  first  tube.  Next  comes 
the  detector,  from  whose  plate  circuit 
the  detected  and  audio  frequency  im- 
pulses are  led  back  to  the  first  tube 
through  an  audio  frequency  transformer, 
"a."  Its  secondary  is  inserted  in  the 
grid  return  lead  from  the  loop  tuning 
circuit  to  the  movable  arm  of  a  potenti- 
ometer. Tube  No.  1  thus  amplifies  at 
audio  frequency  and  the  amplified  audio 
impulses  pass  without  opposition  through 
the  primary  winding  of  the  first  R.  F. 
transformer  to  the  second  audio  trans- 
former, "b."  Here  they  are  transferred 
with  amplification  to  the  next  tube, 
No.  2,  which  again  amplifies  at  audio 
frequencies  and  passes  the  energy  along 
to  tube  No.  3.  In  the  plate  circuit  of 
this  tube  we  find  the  loud  speaker  "L.S." 
whereby  the  impulses  are  rendered 
audible. 

Now,  it  is  well  known  that  the  extent 
to  which  a  radio  frequency  amplifying 
tube  will  strengthen 
the  weak  R.  F. 
impulses  is  depend- 
ent upon  the  close- 
ness'of  its  approach 
to  the  point  of  os- 
cillation. In  other 
words,  there  must 
be  a  certain  degree 
of  tuning  in  plate 
and  grid  circuits 
of  each  R.  F.  ampli- 
fier tube  and  a 
sufficient  negative 
bias  (not  too  much) 
to  bring  about  a 
condition  of  regen- 
eration, but  not  of 
oscillation.  Thus, 
most  R.  F.  iron- 
core  transformers 
are  designed  to  do 
and  are  intended 
to  have  the  grid 
return  leads  go  di- 
rect the  negative 
of  the  filament  bat- 
tery. But  in  the 
case  of  the  first, 
tube,  the  grid  cir- 
cuit does  not  have 
the  high  resistance 


Now,  it  isn't  intended  that  such  a 
receiver  shall  weigh  so  much  that  it's 
only  portable  when  tackled  by  a  corps 
of  furniture  movers  or  a  traveling  crane. 
It  must  be  light  enough  to  be  lifted  easily 
and  carried  about  just  like  a  small  suit- 
case. And  above  all,  it  must  include  a 
loud  speaker,  for  who  cares  to  use  head- 
phones for  group  entertainment? 

These  rigid  requirements  instantly 
call  to  mind  what  type  of  receiver  the 
portable  set  must  be.  It  must  operate 
on  a  small  loop  antenna,  must  use  dry 
cell  tubes,  must  have  at  least  three  steps 
of  radio  frequency  amplification,  must 
have  at  least  two  steps  of  audio,  prefer- 
ably three  steps  of  it,  and  must  be  selec- 
tive and  sensitive  besides.  Is  there  any 
such    thing? 

Triple  Reflexing 

TO  embody  three  radio  and  three  audio, 
besides  a  tube  detector,  seven  tubes 
would  ordinarily  be  necessary,  unless 
we  resort  to  reflexing.  This,  then,  is 
a  most  valuable  method  of  reception  not 
only  for  its  economy  of  expensive  tubes, 
but  quite  as  much  on  account  of  its  space 
saving  possibilities  and  the  reduction  in 
battery  consump- 
tion. You  may 
say  offhand  that 
to  reflex  sufficiently 
would  use  each  of 
three  tubes  as  both 
radio  and  audio  am- 
plifiers and  a  fourth 
as  the  detector. 
This  arrangement, 
you  may  suppose, 
will  howl  and  squeal 
so  unmercifully  that 
it  would  be  next  to 
impossible  to  get 
it     functioning. 

Not  so,  however, 
for  experiments  with 
all  sorts  of  R.  F. 
and  A.  F.  trans- 
former combina- 
tions have  con- 
vinced me  that  in 
every  case  the  stunt 
will  work  and  work 
well,  though  not 
without  consider- 
able reversals  of 
audio  transformer 
connections  and  the 
judicious  use  of  var- 
ious sizes  of  by-pass 


condensers  as  individually  demanded. 
Moreover,  the  size  of  the  loop  with  which 
such  a  circuit  will  perform  local  and  DX 
reception  is  indeed  astonishing!  Take 
the  set-up  illustrated,  for  instance.  The 
loop  is  wound  on  a  cigar  box  of  the 
ordinary  proportions,  using  common 
No.  20  enamelled  magnet  wire  for  the 
winding,  and  enough  turns  to  cover  the 
broadcast  wavelength  band  with  the 
13   plate  tuning  condenser  shown. 

Four  UV  199  tubes  are  employed  in 
the  outfit,  together  with  three  tuned  iron 
core  R.  F.  transformers.  The  trans- 
former at  the  extreme  right  is  an  audio 
transformer,  not  an  R.  F.,  its  appearance 
being  similar  since  the  same  sort  of  con- 
tainer is  used  by  the  manufacturers  as 
for  their  R.  F.  transformers.  The  other 
two  audio  transformers  may  be  observed, 
one  at  the  left,  just  behind  the  tuning 
condenser  and  the  other  behind  the 
potentiometer. 

The  layout  was  tried  in  several  different 
ways,  to  discover  what  effect  criss-cross- 
ing of  wires  and  juxtaposition  of  R.  F. 
coils  would  have  upon  the  results.  The 
set  functioned  as  well  one  way  as  another, 


Here's  an  experimental  outfit  that  functions  on  a  cigar-box  loop  antenna  and 
gets  DX  in  addition  to  local  stations  on  the  speaker.  It  uses  three  radio,  three 
audio  and  tube  detector,  reflexed  in  such  a  way  as  to  require  only  four  tubes.  If 
you'd  like  to  build  a  really  complete  portable  set  in  a  suit-case,  try  this  with  these 
temporary  connections  and  surprise  your  friends. 


22 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


and  iron  core  which  prevents  oscillation 
in  the  case  of  the  other  tubes,  but  instead 
has  a  low  resistance  loop  and  a  sharply 
tuned  circuit. 

Oscillation  is  therefore  present  in  the 
first  tube  unless  means  be  arranged  to 
vary  the  negative  bias,  and  the  potenti- 
ometer is  therefore  installed  to  effect 
this  sensitivity  control.  The  secondary 
of  the  audio  transformer  must  be  shunted 
by  a  by-pass  condenser  of  sufficient  size 
to  pass  the  R.  F.  impulses  past  the  high 
impedance  winding.  Were  the  con- 
denser omitted,  the  tuning  would  be 
too  broad  and  oscillation  impossible  to 
secure.  But  condenser  C-l  must  not 
be  large,  for  it  then  exerts  a  deleterious 
effect  upon  the  audio  frequency  side  of 
the    amplifier. 

Audio  Amplification 

HAVE  you  ever  shunted  a  .002  mfds. 
fixed  condenser  across  the  secondary 
of  your  audio  transformer  and  observed 
the  alteration  in  quality  of  tone?  Music 
becomes  more  mellow,  though  at  a  con- 
siderable loss  in  volume.  If  the  con- 
denser be  small  enough,  the  mellowing 
of  tone  is  obtained  to  a  sufficiently  pleas- 
ing extent  without  any  great  lessening 
of  signal  volume  and  consequently  a 
condenser  of  about  .00025  mfds.  is  often 
employed    for   such    a   purpose. 

The  self-same  effect  is  felt  here.  Too 
large  a  capacity  at  C-l  will  greatly  cut 
the  volume,  but  too  small  a  capacity 
will  spoil  the  sensitivity.  The  trans- 
former ratio  exercises  the  controlling 
power  over  the  exact  size  of  fixed  con- 
denser needed  and  therefore  the  ex- 
perimenter should  have  a  supply  of  fixed 
condensers  of  .00025  mfds.,  .0005  mfds. 
and  .001  mfds.  on  hand;  say,  about 
three  of  each.  These  three  sizes  will 
satisfactorily  fill  the  bill  and  by  a  proper 
distribution  of  these  condensers  to  the 
various    audio    amplifying    transformers, 


a  happy  condition  of  sensitiveness  and 
good  volume  will  be  arrived  at. 

Without  by-pass  condensers  across 
the  audio  transformer  secondaries  of 
tubes  No.  2  and  No.  3  or  across  the  loud 
speaker,  local  stations  can  be  heard 
loudly  and  clearly,  but  the  sensitiveness 
to  DX  signals  is  rather  poor.  Con- 
denser C-l,  however,  is  a  real  essential, 
before  any  signals  will  be  heard  with 
any  sort  of  strength.  Once  the  set  is 
working  on  locals,  however,  it  becomes 
a  simple  matter  to  test  with  the  different 
sizes  of  condenser  at  the  points  recom- 
mended. It  is  not  necessary  to  use  by- 
pass condensers  in  the  'primary  circuits, 
however.  Condenser  C-5  is  of  utmost 
importance,  it  being  a  .002  mfds.  by-pass 
condenser  for  the  plate  circuit  of  the 
detector  tube. 

It  is  by  the  use  of  these  by-pass  con- 
densers that  we  obtain  a  condition  of 
regeneration  in  each  R.  F.  amplifier, 
but  we  must  avoid  too  high  a  capacity 
in  any  of  the  points  where  good  signals 
are  obtained  without  the  condenser  for 
the  sake  of  maintaining  volume  and 
clear  tone.  Condenser  C-2  is  usually  a 
.00025  mfds.  size,  C-3  a  .0005  mfds.  and 
C-4,  if  found  necessary,  a  .001  or  .0005. 
Remember,  tone  and  volume  are  better 
without  the  condensers  unless  the  sensi- 
tivity is  too  low  without  them,  so  use 
only  what  condensers  show  themselves 
to  be  needed  and  no  others. 

Now  as  to  the  battery  voltages.  Two 
standard  dry  cells,  three  volts,  can  supply 
the  filament  current  direct  without  a 
rheostat.  The  rheostat  illustrated  was 
employed  experimentally  to  determine 
how  much  filament  current  is  necessary 
and  the  set  operates  well  on  slightly 
under  3  volts.  Hence  two  dry  cells 
furnish  sufficient  current,  as  proved  also 
by  later  trials.  For  the  "B"  battery, 
better  results  were  secured  with  673^ 
volts  than   with   90,   which   is   fortunate 


because  of  the  space  saving  feature. 
Thus,  two  dry  cells  and  three  small  size 
22H  volt  "B"  batteries  were  found  to 
supply  the  necessary  filament  and  plate 
energy. 

Transformer  Reversals 

\  NYONE  who  has  experimented  with 
-^*-  a  three  stage  audio  amplifier  has 
found  a  strong  tendency  to  "howl"  or 
oscillate  at  audio  frequency.  This  is 
just  like  a  radio  frequency  oscillation 
in  its  nature,  except  that  inasmuch  as 
the  tuning  which  causes  such  howling 
is  accomplished  by  very  large  windings 
on  iron  cores,  the  oscillation  is  reduced 
in  frequency  to  a  point  where  it  is  heard. 
This  howling  is  not  affected  by  adjust- 
ments of  the  tuning  condenser,  though 
it  may  be  changed  in  pitch  or  stopped 
by  moving  the  potentiometer  arm. 

The  audio  transformers  shouldn't  be 
too  close  to  each  other,  of  course,  but 
with  good  transformers  it  isn't  necessary 
to  place  them  at  right  angles  unless  they 
are  so  close  as  to  nearly  touch  each  other. 
The  heavy  iron  core  prevents  the  mag- 
netic fields  from  straying  and  in  that 
way  causing  howling  by  interstage  audio 
coupling.  The  trouble  is  due  only  to 
oscillation  caused  by  circuits  tuned  to 
an  audio  frequency,  and  with  connec- 
tions arranged  so  that  the  direction  of 
current  flow  aids  the  oscillation  tendency. 

Hence  the  howling  can  always  be 
eliminated  by  reversing  the  transformer 
connections  in  the  grid  circuit  of  the  tube 
which  causes  the  trouble.  Since  you 
cannot  discover  except  by  trial  just 
where  the  howling  commences,  it  is  a 
question  of  reversing  one  or  two  of  the 
primary  binding  post  connections  till 
the  noise  stops.  This  howling,  unless 
caused  by  the  first  tube  (No.  1)  is  not 
stopped  when  the  detector  tube  is  taken 
out  of  the  socket  and  the  others  allowed 
(Turn  to  page  62) 


\    LOOP 


C-l         '^i 


DETECTOR. 


S      C-3 


X  3  VOLTS 


22fY 


The  circuit  is  quite  conventional,  though  quite  a  few  of  the  myriad  fixed  condensers  common  to  the  complicated  reflex  sets  are  omitted. 
There's  only  one  tuning  control  and  one  sensitivity  control;  a  condenser  and  a  potentiometer.  Two  dry  cells  light  the  tubes  and  three  small 
"B"  batteries  can  supply  the  plate  voltage. 


RADIO  AGE  for  January,   1925 

How 

To  Construct  A 
Station  Finder 


The  Magazine  of  the  Hour  23 


By 
FELIX  ANDERSON 


C.A  Novel  Unit 
That  will  Cut 
out  Guesswork 
in  Tuning  and 
Help  Reduce 
The  Annoying 
Set  "Squeals" 


THIS  radio  pastime  is  at  last  getting 
to  a  point  where  enthusiasts  no 
longer  are  satisfied  with  the  old 
haphazard  methods  of  tuning,  and  the 
out-of-date  system  of  radio  "fishing"  is 
resorted  to  only  as  a  means  of  entertain- 
ment nowadays.  The  up-to-date  listener 
seeks  to  go  after  the  long  distance  sta- 
tions in  a  more  accurate  and  sure-fire 
way;  he  endeavors  to  get  the  results  he 
wants  by  employing  the  right  methods 
of  tuning. 

The  recent  transatlantic  broadcasting 
tests  prove  conclusively  that  there  is  a 
pressing  need  for  a  unit  which  will 
eliminate  the  guesswork  variety  of  tuning, 
insure  more  certain  results,  and  at  the 
same  time  reduce  the  nuisance  of  radia- 
tion which  broke  up  more  than  one 
reception  of  the  foreign  stations.  You 
will  no  doubt  recall  the  pandemonium 
of  squeals  and  howls  which  prevailed  in 
the  air  during  that  memorable  week. 
And  no  doubt  you  more  than  once 
"cussed"  some  neighbor  softly  when  you 
found  that  you  had  been  trying  to  tune 
in  his  radiation.  There  were  times  when 
we  gave  up  in  disgust,  loudly  voicing  our 
disrespect  for  those  bugs  who  couldn't 
keep  their  hands  off  the  controls,  and 
who  constantly  interfered  with  the  in- 
coming long  distance  signals  with  their 
malicious  squeals. 

The  underlying  reason  for  all  the 
trouble  and  the  real  cause  for  the  cease- 
less search  for  the  carrier  waves  or 
signals  of  the  European  stations,  can  be 
directly  attributed  to  one  main  and 
grand  reason.  Listeners  in  general  are 
not  so  fortunate  as  to  have  sets  that  are 
calibrated;  that  is,  they  do   not   possess 


a  receiver  that  tells  them  where  to  set 
the  dials  for  definite  wavelengths.  So 
the  logical  way  to  get  the  much  sought 
receptions  was  to  guess — fish,  in  other 
words,  until  you  struck  something  that 
sounded  promising,  and  then  listen  until 
the  announcement  was  made;  or  until 
some  other  bug  spoiled  it  all  by  squealing 
you  out. 

The  Right  Way  to  Do  It. 

TT  WOULD  be  impossible  to  set  down 
-*-  specified  rules  for  the  calibration  of 
every  receiver  now  in  use.  It  is  a  fact 
that  there  are  some  sets  which  cannot 
be  calibrated  because  of  their  circuit 
peculiarities.  What  we  can  do,  for- 
tunately, is  make  a  separate  unit  and 
calibrate  that  instrument,  and  then  tune 
our  receivers  to  it  instead  of  fishing. 
The  result  is  that  we  make  only  one 
operation  of  the  job,  and  then  we  know 
that  we  are  accurate  and  that  we  are 
listening  on  the  right  wave.  Therefore, 
the  purpose  of  this  article  is  to  describe 
a  unit  of  this  type. 

For  purposes  of  reference,  we  will  call 
the  unit  about  to  be  described  and  dis- 
cussed a  "Station  Finder."  Its  technical 
name  is  wavemeter,  or  probably  more 
correctly  a  driver — but  that  matters  only 
little.  What  we  are  after  is  a  unit  that 
is  going  to  tell  us  where  to  set  our  dials 


In  the  circle  is  a  three-quarters  view 
of  Air.  Anderson's  station-finder,  giving  an 
unusual  angle  of  the  buzzer  and  the  switch. 
At  the  left  is  a  top  view,  showing  the  dial 
with  its  valuable  hair-line  indicator. 


when  we  want  to  listen  for  a  certain 
station,  the  wave  of  which  we  are  in- 
formed. 

The  preceding  paragraph  probably 
sounds  a  little  imposing,  and  no  doubt 
you  have  visions  of  a  mighty  piece  of 
apparatus  with  all  the  embellishments 
that  usually  go  with  a  measuring  device; 
but  that  is  not  the  case.  The  station 
finder  is  a  simple  affair,  and  not  in  the 
least   bit   expensive. 

The  Bill  of  Materials 

TF  YOU  have  the  parts  listed  below — 
-I  all  well  and  good;  if  not,  a  visit  to  the 
local  radio  store  will  be  necessary. 

1  Cabinet  7  inches  long,  6  inches 
wide  and  6  inches  deep.  Get  a  neat 
one,  and  make  the  job  a  good  looking 
one. 

1  Composition  panel  7x6x>6  inches, 
Bakelite,  Celeron,  Formica,  Spaulding 
or  other. 

1  low  Loss  Straightline  condenser. 
Eleven  plate  250  MMF.  (0.00025 
Mfd).  The  straightline  plates  are 
advised  for  the  purpose  of  making 
calibration  easier.     See  text  of  article. 

1  Cardboard  tube  3}4  inches  long 
and  i^i  inches  in  diameter. 

2  pieces  of  brass  2%  inches  long  and 
}4  inches  wide.  Any  fairly  heavy 
gauge  will  do. 

j|  pound  No.  22  Double  Green  Silk 
Covered  wire. 

2  Binding  posts. 

1   Dial  reading  0  to  100°.    A  metal 

dial   with   well   etched   divisions  that 

.  are  easy  to  read  is  suggested,  since 

the   readings   on   it   are   hair   line   in 

cases. 

1  High  frequency  buzzer.  One 
that  will  operate  on  flashlight  or  C 
batteries,  and  give  a  steady  clear  note. 

1  Switch  lever. 

(Turn  the  page) 


24 


RADIO  AGE  for  January,  1925 


Figure  2. 
//  your  condenser  is  one  that  does  not   have  straight-line  plates, 
your  calibration  chart   will    look   something   like    the   above.      In 
this   case   numerous   readings  make  the  curve  especially  accurate. 


2  Switchtaps. 

2  Three  volt  C  batteries  or  four  1  Yi 
volt  flashlight  batteries.  Busbar  and 
stiff  rubber  covered  wire,  preferably 
No.  18  RC,  mounting  screws,  solder, 
etc. 

The  above  list  includes  everything  you 
will  need.  As  a  word  of  caution,  don't 
let  them  sell  you  anything  "just  as  good" 
in  the  condenser  line — make  it  a  point 
to  try  obtaining  one  of  the  straight-line 
variety. 

Building  the  Station  Finder 

THE  construction  is  very  simple. 
About  the  only  thing  we  have  to 
avoid  is  getting  the  inductance  or  coil 
too  close  to  the  rest  of  the  unit,  or  to 
get  it  too  close  to  the  hands  or  dial; 
bringing  any  foreign  object  within  the 
field  of  the  coil  changes  its  wavelength, 
and  as  a  consequence,  the  readings  of 
the  dial  are  inaccurate. 

Begin  by  preparing  the  cardboard 
tubing  which  is  to  be  the  winding  form. 
Apply  a  light  coating  of  shellac,  spar 
varnish  or  better  yet  a  very  thin  coating 
of  a  solution  of  celluloid  dissolved  in 
acetone.  If  the  tube  is  not  dry,  it  should 
be  thoroughly  warmed  in  an  oven  before 
the  moisture  impregnating  compound  is 
applied. 

When  this  has  been  done,  and  the 
coil  is  still  slightly  sticky  (not  wet),  two 
holes  should  be  punched  about  i/i  of 
an  inch  from  the  edge.  Thread  the  No. 
22  DGSC  wire  into  these  holes,  and 
begin  winding  the  coil  in  a  clockwise 
direction,  (face  a  clock  and  wind  the 
wire  in  the  direction  of  the  hour  hand 
with  the  edge  of  the  tube  having  the 
holes  in  it  away  from  you). 

If  you  use  a  condenser  of  the  type 
specified  and  a  coil  of  exactly  the  same 
size  as  is  mentioned,  wind  59  turns  of 
the  wire  on  the  tube.  Wind  them  tightly 
and  neatly.  If  the  varnish  or  dope  you 
have  applied  is  sticky  enough,  you  should 


have  little  or  no  trouble  with  slipping 
turns.  When  the  winding  has  been 
finished  punch  two  additional  holes 
(opposite  the  beginning  ones)  and  fasten 
the  wire  once  more.  It  is  understood 
of  course  that  you  leave  sufficient  ends 
at  both  start  and  finish  to  allow  soldering 
to  terminals. 

Now  drill  two  holes  in  the  brass  strips, 
large  enough  to  accommodate  an  8-32 
bolt.  The  exact  location  of  the  holes 
is  not  a  matter  of  great  importance;  one 
half  inch  from  either  end  to  their  center 
is  satisfactory.  The  one  end  of  the  strip 
is  then  bent  to  form  a  foot,  which  is 
screwed  tightly  against  the  cardboard 
tubing.     The  ends  of  the  coil  are  then 


The  Magazine  of  the  Hour 

soldered  to  these  connection  legs.  The 
purpose  of  these  extended  legs  i's  to 
suspend  the  coil  in  midair  and  also  to 
permit  its  being  coupled  to  the  main 
tuning  inductance  of  the  receiver. 

Mount  the  condenser  as  illustrated 
in  the  photograph.  A  hairline  should 
be  deeply  scratched  in  the  panel,  and 
filled  with  either  jeweler's  wax  or  some 
other  white  compound  to  make  it  plain. 
This  line  should  be  drawn  carefully  and 
accurately,  and  should  be  very  thin 
indeed.  (As  a  matter  of  information,  we 
filled  the  line  with  Bon-Ami,  which 
hardens  and   makes  an   excellent   filler.) 

The  binding  post  for  the  coil  should 
then  be  screwed  into  place. 

On  the  side  of  the  box  which  is  to  be 
opposite  the  one  occupied  by  the  binding 
posts  and  the  coil,  mount  the  buzzer 
and  switch  with  the  taps.  Figure  4 
shows  the  mounting  used  on  the  test 
Station  Finder.  Holes  should  be  drilled 
to  allow  for  wiring. 

Wiring 

YOU  are  next  ready  to  wire  the  Station 
Finder,  and  again  we  find  simplicity 
the  keynote.  Connect  the  one  binding 
post  (it  makes  no  difference  which  one) 
to  the  stationary  plate  connection  of 
the  condenser,  and  the  other  binding 
post  to  the  rotary  terminal.  Next 
connect  the  one  terminal  of  the  buzzer 
to  the  left  hand  switchpoint,  and  connect 
the  switch  lever  to  the  cells  of  the  battery. 
Polarity  is  not  important.  The  other 
open  terminal  of  the  battery  is  connected 
to  the  remaining  terminal  of  the  buzzer. 
Use  busbar  in  wiring  the  condenser  cir- 
cuit, and  the  rubber  covered  wire  for 
the  buzzer  circuit. 

On  the  buzzer  you  will  find  an  adjust- 
ment for  varying  the  pitch  and  some  place 
on  the  metal  support  holding  the  adjust- 
ing screw  or  on  some  piece  of  metal 
connected  to  this  screw,  solder  another 
piece  of  the  rubber  covered  wire.  Then 
solder  the  other  end  of  that  same  wire 


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Figure  3. 
The  graph  obtained  with  the  test  station-finder  is  shown  above.   Straight- 
line  plates  were  used  in  this  finder,  as  the  curve  will  show  graphically. 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


25 


to  the  rotary  plate  terminal  on  the 
condenser.  You  will  then  have  two 
wires  at  that  terminal,  one  for  the  coil 
and  binding  post,  and  the  other  to  the 
buzzer  or  exciter  circuit. 

The  last  two  mentioned  operations 
are  important,  especially  the  matter  of 
getting  the  right  connection  to  the 
buzzer.  We  find  in  the  tests,  that  any 
other  connection  works  poorly  indeed. 
Make  sure  that  the  one  end  of  that  wire 
goes  to  the  adjustment  part  of  the  buzzer, 
or  some  metal  connected  or  in  direct 
contact  with  it.  The  object  is  to  get  the 
little  spark  across  the  buzzer  contacts 
to  charge  the  coil  and  condenser,  and 
in  that  way  act  as  a  miniature  trans- 
mitter. 

After  making  sure  that  the  buzzer 
circuit  is  properly  connected,  screw  the 
panel  down  on  the  cabinet,  and  fasten 
the  coil.  It  might  be  well  to  explain 
the  reason  for  the  use  of  the  two  switch- 
points — the  object  is  to  provide  an 
open  circuit  for  the  buzzer  when  not 
in  use. 

Next  put  the  brass  legs  of  the  coil  on 
the  binding  posts,  and  tighten  them  down. 
Your  next  job  (and  probably  the  most 
interesting  radio  experiment  you  can  do 
as  a  beginner)  is  to  calibrate  the  Station 
Finder. 

Calibrating 

CALIBRATING  in  our  case  means 
that  we  must  find  out  what  wave- 
length the  oscillatory  circuit  composed 
by  the  condenser  and  coil  responds  to 
with  various  settings  of  the  condenser 
dial,  and  further  it  means  that  we  are 
enabled  to  read  the  condenser  in  terms  of 
wavelengths  instead  of  degrees. 

The  first  step  in  this  procedure  is  to 
rule  out  a  sheet  of  paper  as  illustrated  in 
Figure  3.  This  is  what  is  called  a 
calibration  graph,  and  will  give  us  a 
wavelength  curve  for  the  coil  and  con- 
denser combination  we  are  using. 

Make  a  rectangle  10  inches  long  and 
divide  it  into  one-half  inch  lengths. 
The  other  dimension  is  7  inches,  also 
divided    into    half 

inch     divisions.        

Then  proceed  to 
rule  up  the  chart 
as  illustrated. 
When  you  have 
finished,  you  will 
have  a  rectangle 
having  20  half- 
inch  squares  for 
its  base  and  14 
for  its  attitude. 
Number  the  lines 
along  the  base  by 
fives,  starting  with 
zero.  These  num- 
bers correspond 
with  the  dial  set- 
tings of  the  con- 
denser. The  ver- 
tical left  hand  side 
is  numbered  off 
in  twenty-fives, 
starting  at  200, 
and    going    up    to 

550.  This  corresponds  to  the  wavelength 
range  which  we  are  seeking  to  cover. 

Now  the  calibrating  method  differs 
with    regenerative    and    nonregenerative 


sets,  so  we  had  best  take  up  the  methods 
separately.  With  a  non-regenerative 
set,  it  is  merely  necessary  to  bring  the 
Station  Finder  coil  within  about  two  or 
three  inches  of  the  main  tuning  induct- 
ance, neutrocoupler,  variocoupler,  tuning 
coil  or  other  coil  used  to  tune  with.     It 


A  back  view  of  the  station  finder  is  shown 
above.  The  -oil  is  in  the  background,  while 
the  switch,  at  the  "off"  position,  is  shown 
at  the  nght.  The  instrument  at  the  left 
is  a  buzzer  with  its  accurate  adjustment 
screw. 

will  even  work  on  a  crystal  set,  and  in 
the  tests,  we  got  readings  with  four  inch 
coupling.  When  you  have  the  coil  fairly 
close  to  the  tuning  inductance  of  the  set, 
(which  should  be  tuned  to  resonance 
with  some  stations'  wavelength)  turn 
the  Station  Finder  dial  until  the  signal 
is  trapped  out.  Then  move  the  coil 
further  and  further  away,  wiggling  the 
dial  very  slightly  until  the  sharpest 
reading  is  obtained.  At  a  certain  point 
you  will  find  a  setting  of  the  Station 
Finder  dial  which  will  almost  entirely 
if  not  entirely  trap  out  the  signal  to 
which    vour    receiver    is    tuned.      After 


SZQT/QN  FJNDFP    W/R/A/G-  £>//)6-/Q/)A1 


CO//. 


CONDENSeR 


suzze^ 


you  have  found  that  point  with  the 
Station  Finder,  be  careful  not  to  disturb 
the  reading,  and  make  note  of  the  dial 
setting  (that  is,  take  note  of  the  number 


of  degrees  at  which  the  dial  is  set).  Then 
take  your  broadcast  list  and  look  up  the 
wave  of  the  station.  Jot  that  down  too. 
Now  then,  take  your  pencil,  and  put  a 
dot  at  the  point  where  the  wavelength 
and  dial  reading  lines  intersect.  (For 
instance  suppose  WEBH  is  tuned  in, 
and  it  is  found  that  it  can  be  sharply 
trapped  out  with  the  Station  Finder  set 
at  44.  The  wavelength  is  360.  Then  by 
drawing  a  light  line  vertically  from  the 
44  division  on  the  chart,  and  another  at 
the  360  division  horizontally  we  will 
determine  a  place  where  the  two  lines 
meet.     That's  where  the  dot  is  made). 

Go  up  and  down  the  scale  of  your 
receiver,  getting  readings  on  as  many 
stations  as  you  can  possibly  get.  Make 
your  readings  carefully  and  accurately, 
and  check  them  once  or  twice.  After 
you  have  made  about  six  or  eight  of  these 
readings  well  placed  over  the  scale,  you 
can  draw  a  curve  or  line  smoothly  con- 
necting these  points.  If  a  straightline 
condenser  is  used,  the  condenser  graph 
will  read  almost  in  a  straight  line  from 
the  bottom  of  the  scale  to  the  top.  If 
your  condenser  is  not  of  the  straightline 
plate  type,  your  curve  will  look  like  the 
one  shown  in  Figure  2. 

Regenerative  Sets 

X^OR  regenerative  sets,  we  have  as  an 
-*-  additional  indicator,  the  regenerative 
feature  of  the  receiver.  In  this  case,  as 
in  the  case  of  non-regenerative  sets,  we 
bring  the  Station  Finder  coil  near  the 
tuning  inductance  of  the  receiver.  The 
regeneration  is  then  advanced  to  the 
point  where  it  just  spills  over  (this  is  of 
course  with  the  secondary  or  tuning 
circuit  tuned  to  some  station  or  signal 
the  wavelength  of  which  is  known).  The 
Station  Finder  dial  is  then  juggled  until 
the  set  stops  oscillating,  and  the  signal 
is  trapped  out.  Usually  with  regenera- 
tive sets  it  is  more  pronounced  with 
regard  to  this  reading  than  with  non- 
regenerative  receivers.  The  station  is 
then  looked  up,  the  wavelength  and 
dial  setting  (of  the  Station  Finder) 
noted,  and  the  dot 
is  made  on  the 
chart  in  the  same 
manner  as  was 
described  for  non- 
regenerative    sets. 

How  It  Gets  Its 
Name 

OW  you  have 
probably  won- 
dered why  we  need 
a    buzzer    on    the 
thing.      Simple — . 
Now    suppose    we 
had  calibrated  the 
Station  Finder  dial 
to  the  curve  shown 
in  Figure  3.  Again 
suppose   we    were 
going  to  listen  for 
Europe  with  a  non- 
regenerative    set, 
with  which  we  were 
not  acquainted 
as     far     as     wavelength      settings      are 
concerned.    It  is  our  wish  to  listen  to  a 
500    meter    station    which    we    know   is 
(Turn  to  page  54) 


N( 


26  RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


The  Latest  Edition  of  One  of  America's 


Adding  TWO  STAGES  of  Audio 


TO  the  readers  of  RADIO  AGE  'way 
back  in  the  early  days,  the  mention 
of  the  name  of  John  L.  Reinartz 
brings  back  many  pleasant  recollections. 
At  that  time  very  little  was  known  about 
receiving  sets,  and  Reinartz  gave  to  the 
fans  one  of  the  best  circuits  ever  pub- 
lished and  one  which  to  this  day  is  hold- 
ing its  own  against  the  hundreds  of  later 
circuits. 

John  L.  was  about  two  years  ahead  of 
the  times,  and  judging  from  his  rapid 
fire  development  of  new  circuits,  he  is 
still  keeping  up  this  reputation. 

When  the  Reinartz  circuit  first  ap- 
peared, practically  only  one  good  re- 
ceiving circuit  was  then  used,  this  being 
the  Armstrong  three  circuit  tuner,  which 
was  hard  to  make  in  those  days  for  the 
reason  that  it  was  necessary  for  one  to 
build  his  own  variometers  and  couplers, 
as  radio  stores  were  unheard  of  and  the 
wooden  stator  blocks  and  rotors  had  to 
be  turned  out  in  a  lathe.  The  inductance 
units  used  in  the  Reinartz  tuner  were 
simple  spider-web  coils  wound  upon  a 
slotted  fiber  disc,  which  anyone  could 
make  and  wind  without  the  use  of  a  lathe 
or  any  other  machinery. 

Thus  it  attracted  the  beginner,  be- 
cause it  made  possible  the  construction 
of  a  three  circuit  tuner  in  the  ordinary 
kitchen  work  shop,  and  those  who  were 
interested  enough  to  build  the  set  as  des- 
cribed by  Mr.  Reinartz  were  well  repaid 
for  their  trouble,  as  it  proved  to  be  a  good 
long  distance  receiver. 

A  Popular  Circuit 

TN  fact,  it  became  so  popular  with  our 
-*■  readers  that  it  was  necessary  for 
RADIO  AGE  to  publish  a  special  Rein- 


artz book  to  supply  the  information  and 
take  care  of  the  correspondence  oc- 
casioned by  the  publication  of  the  article. 
Since  that  time  several  modifications  of 
the  circuit  have  been  developed,  every 
one  of  which  has  been  just  as  popular,  or 
more  so,  than  the  original.  The  one 
shown  in  this  issue  is  considered  the  best 
and  by  popular  request  it  is  shown  with  two 
stages  of  audio  frequency  amplification. 
It  will  be  noted  that  the  spider  web 
winding  has  been  replaced  by  a  simple 
coil  winding  and  a  variometer.  The  coil 
is  much  easier  to  wind  than  the  spider 
web  arrangement  and  variometers  are 
now  very  easy  to  procure.  The  original 
circuit,  being  of  the  regenerative  type, 
naturally  caused  some  radiation.  This 
is  now  taken  care  of  by  using  a  potentio- 
meter in  the  aerial  circuit,  although  in 
this  case  it  is  used  as  an  ordinary  variable 
resistance  instead  of  a  stabilizer.  One  of 
the  switches  used  in  the  original  circuit 
has  also  been  eliminated,  thus  making  the 
tuning  of  the  set  a  simple  matter. 

Before  going  into  details  regarding  the 
construction  of  this  receiver,  it  might  be 
well  to  say  something  about  the  audio 
frequency  amplification.  Three  spring 
jacks  are  used,  making  it  possible  to  listen 
in  on  the  detector  only,  detector  and  one 
stage,  or  with  the  detector  and  both 
stages.  For  use  with  an  ordinary  phone, 
the  first  jack  will  give  ample  volume  on 
either  local  or  long  distance  reception, 
but  when  the  loud  speaker  is  used,  full 
amplification  is  obtained  by  plugging 
into  the  last  jack.  The  selection  of  the 
transformers  will  have  much  to  do  with 
the  quality  of  the  reception  obtained.  It 
is  a  well  known  fact  that  with  trans- 
formers   of    high    winding    ratios,    more 


By  FRANK  D.  PEARNE 

volume  may  be  obtained,  but  such  trans- 
formers will  also  cause  considerable  dis- 
tortion in  the  phones  or  loud  speaker, 
and  as  ample  volume  may  be  had  with 
low  ratio  transformers,  the  builder  is 
advised  to  be  careful  in  the  selection  and 
to  choose  transformers  which  do  not 
have  a  high  ratio.  If  one  has  a  higher 
ratio  then  the  other,  it  is  suggested  that 
the  ordinary  practice  be  reversed  and  the 
higher  ratio  used  in  the  last  stage,  thus 
cutting  down  the  distortion  in  the  first 
stage,  which  will  prevent  any  amplifi- 
cation of  distortion  in  the  second.  In 
either  case  the  ratio  should  not  be  more 
than  five  to  one. 

If  You  Want  Volume 

OF  course,  if  one  wishes  great  volume 
and  does  not  care  about  distortion, 
a  transformer  having  a  ratio  of  ten  to 
one  may  be  used  in  the  first  stage,  and 
one  of  five,  or  six-to-one  in  the  second. 
The  only  special  apparatus  necessary  is 
the  inductance,  which  may  be  easily 
wound  and  constructed  in  the  home 
workshop.  This  inductance  is  wound  on 
a  bakelite  or  cardboard  tube  4  inches  in 
diameter  and  3  inches  long.  The  winding 
instructions  should  be  followed  to  the 
letter  as  the  only  cases  of  failure  so  far 
recorded  were  caused  by  variations  in 
the  number  of  turns  used  and  taps  being 
taken  off  at  the  wrong  place. 

The  tube  is  wound  with  No.  24  cotton 
or  silk  insulated  wire  and  in  order  that 
no  short  circuits  may  occur  at  the  points 
where  the  taps  are  taken  off,  it  is   sug- 


RADIO  AGE  for  January,   1925 


The   Magazine  of  the  Hour 


27 


Pioneer  Receivers:    The  Popular  Reinartz 


The  electrical  wiring  diagram  of  the  Improved 
Reinartz  Circuit  is  shown  above.  At  the  left  the  re- 
ceiver is  shown  in  isometric  form,  which  makes  the 
tracing  of  the  connections  a  simple  operation.  Inas- 
much as  both  diagrams  are  drawn  to  read  from  left 
to  right,  you  should  have  little  or  no  trouble  in  following 
out  the  connections. 


H 


+  A 


Mi  i 


JMlo. 


Frequency  to  Modified  Reinartz 


TECHNICAL  EDITOR 

gested  that  the  wire  used  should  have  a 
double  silk  insulation.  The  winding  is 
started  after  two  small  holes  (about  the 
size  of  the  wire)  are  drilled  in  the  tube 
about  1-2  inch  from  the  end.  These 
holes  should  be  about  1-4  of  an  inch  apart 
and  in  line  with  the  winding.  Put  the 
end  of  the  wire  down  through  one  of 
these  holes  and  up  through  the  other, 
leaving  an  end  about  8  inches  long  to  use 
in  connecting  it  up  after  the  winding  is 
completed.  Wind  two  turns  and  take 
out  a  tap  by  making  a  loop  of  the  wire 
and  twisting  it  back  tight  against  the 
tube.  Bring  out  another  tap  at  the  next 
two  turns,  the  next  one  being  taken  off 
at  the  next  turn  and  two  more  taps  taken 
off  from  the  next  two  turns. 

The  winding  is  now  continued  for  35 
more  turns  before  another  tap  is  taken 
off.  After  this  tap,  wind  seven  more 
turns  and  bring  out  the  next,  then  seven 
more,  which  will  be  the  end  of  the  wind- 
ing. Now  check  up  and  make  sure  that 
this  coil  is  correctly  tapped.  We  have 
the  starting  end,  two  turns  and  a  tap, 
two  more  and  a  tap,  one  and  tap,  one  and 
tap,  one  more  and  tap,  then  35  and  tap, 
seven  and  tap,  then  seven  more,  which  is 
the  final  end.  This  will  make  56  turns  in 
all,  consisting  of  two  ends  and  seven  taps. 
The  final  end  of  the  winding  is  anchored 
to  the  tube  in  the  same  way  as  the  start- 
ing end  by  drilling  two  small  holes.  All 
of  these  taps,  as  well  as  the  ends,  should 
be  left  long  enough  to  allow  for  connecting 
up  to  the  switch  contacts  on  the  panel. 
If  they  are  eight  inches  in  length,  they 
will  be  sure  to  reach  without  splicing. 


TVTOW  the  balance  of  the  material  and 
-L  '  parts  required  may  be  purchased  at 
any  radio  store.  This  will  consist  of  one 
200  ohm  potentiometer,  two  switch 
levers,  eight  switch  contacts,  four  switch 
stops,  one  23  plate  vernier  variable  con- 
denser, one  fixed  mica  grid  condenser 
having  a  capacity  of  .00025  M.F.,  one  2 
megohm  grid  leak,  one  ordinary  standard 
variometer,  three  standard  sockets,  one 
6  to  8  ohm  rheostat,  two  25  ohm  rheo- 
stats, two  double  circuit  spring  jacks,  one 
single  circuit  spring  jack,  two  standard 
audio  frequency  transformers  having  a 
four,  or  five  to  one  ratio,  two  3-inch 
dials,  seven  binding  posts,  one,  bakelite 
panel  18x7x3-16  inches,  one  baseboard 
17  1-2x6x1-2  inches,  a  cabinet  to  fit  an 
18x7  inch  panel  and  about  20  feet  of  No. 
14  tinned  copper  bus  bar  wire.  This 
material  is  only  that  required  for  the 
construction  of  the  set  proper. 

Aside  from  this  the  accessories  will  be 
as  follows: 

Materials  and  Parts 

One  detector  tube  (UV-200,  or  C-300), 
two  amplifier  tubes,  (UV-201-A,  or  C- 
301-A),  two  45  volt  plate  batteries,  one 
6  volt  storage  battery,  one  pair  of  phones, 
one  loud  speaker  and  two  plugs.  With 
these  parts  on  hand,  you  are  ready  to 
start  on  the  wiring.  First  the  panel  is 
laid  out  and  drilled,  after  which  it  is 
fastened  to  one  edge  of  the  baseboard  by 
wood  screws,  the  holes  being  countersunk 
so  that  flat  headed  screws  may  be  used. 
All  the  parts  are  mounted  on  the  base 
and  panel  as  shown  in  the  drawing.  The 
aerial  binding  post  on  the  panel  is  con- 
nected to  the  movable  arm  of  the  poten- 
tiometer and  one  of  the  ends  of  the  resis- 


tance coil  of  the  potentiometer  is  con- 
nected to  the  switch  lever  on  the  five 
contact  switch.  The  bottom  or  starting 
end  of  the  winding  of  the  special  induc- 
tance coil  is  connected  to  the  bottom  con- 
tact on  this  switch  and  the  next  four  taps 
from  the  coil  are  connected  to  the  re- 
maining contacts  on  this  switch.  This 
leaves  one  tap  in  the  bottom  group  which 
is  connected  to  the  ground  binding  post 
to  the  revolving  plates  of  the  23  plate 
variable  condenser,  to  one  filament  bind- 
ing post  on  each  of  the  three  sockets,  to 
the  positive  "A"  and  negative  "B"  bind- 
ing posts  on  the  panel. 

The  two  taps  and  the  final  end  of  the 
winding  of  the  special  inductance  are 
connected  to  the  three  switch  contacts  on 
the  other  switch,  the  lever  of  which  is 
connected  to  the  stationary  plates  on  the 
condenser  and  to  one  terminal  of  the  grid 
leak  and  condenser. 

Watch  These  Connections 

HPHE  other  terminal  of  the  grid  leak  and 
-!■  condenser  is  connected  to  the  grid 
binding  post  on  the  first  socket,  which 
is  the  detector.  The  post  marked  "P" 
on  this  socket  is  connected  to  one  of  the 
variometer  terminals  and  the  other  vario- 
meter terminal  is  connected  to  the  top 
spring  of  the  detector  jack.  The  second 
spring  on  this  jack  is  connected  to  the 
post  marked  "P"  on  the  first  transformer 
and  the  third  spring  from  the  top  is  con- 
nected to  the  post  marked  "B  positive" 
on  the  same  transformer.  The  last  or 
bottom  spring  on  this  jack  is  connected 
to  the  22  1-2  volt  positive  "B"  binding 
post  on  the  panel.  The  post  "G"  on  this 
first  transformer  is  connected  to  the  post 
(Turn  to  page  56) 


28 


RADIO  AGE  for  January,   1925 


What  the  Broadcasters  are  Doin^ 


Let  the  "Happiness  Boyf  Help  You! 


They  Wont 
be  Happy  Till 
They  Make 
You  Happy 
Too! 


Millions  of 

Fans  Cheer 

Peppy  Trio 

at  Station 

WEAF 


Above  are  the  "Happiness  Boys"  of  WEAF,  New  York,  who  cause  the  radio  waves  to  ripple  with  joy 
every  Friday  evening  at  8:30.      From  left  to  right:  Ernest  Hare,  Larry  Briers,   and  Billy  Jones. 


DOWN  EAST  in  little  old  New 
I  York,  people  have  to  work  pretty 
hard  or  they  soon  find  New  York 
is  too  big  to  hold  them.  Of  course,  that 
doesn't  include  the  millionaires,  brick- 
layers and  movie  producers,  but  the 
untold  millions  who  count  their  pennies 
every  Saturday  are  the  ones  who 
haven't  much  time  to  be  happy. 

Three  young  Lochinvars  who  came  out 
of  the  West  a  few  years  ago  were  as- 
tounded at  the  lack  of  good  cheer  in  New 
York  City.  They  saw  the  bright  lights 
and  beautiful  buildings  and  wondered 
how  anyone  couldn't  help  being  happy. 
But  investigation  showed  that  the  aver- 
age citizen  in  New  York  is  so  busy  keep- 
ing alive  that  he  just  can't  afford  to 
chase  pleasure  to  its  lair  and  enjoy  it. 

On  a  Happy  Mission 

AFTER  this  bit  of  introspection,  the 
-£*-  three  musketeers  mentioned  above  as 
Lochinvars  went  to  the  owners  of  WEAF, 
one  of  New  York's  pioneer  broadcasting 
stations — and  volunteered  to  bring  hap- 
piness to  millions  of  American  homes — 
chiefly  in  New  York. 

Radio  was  struggling  for  popularity  in 
those  days,  so  the  directors  of  WEAF 
told  the  boys  to  "go  to  it." 

The  "boys,"  Ernest  Hare,  Larry 
Briers  and  Billy  Jones,  "went  to  it" 
with  a  vim  and  labeled  themselves  the 
"Happiness  Boys."  With  that  monicker 
they  proceeded  to  win  the  hearts  of  bored 
and  weary  New  York. 

To  find  out  whether  they  have  been 
successful,  the  reader  should  tune  in 
WEAF  some  Friday  evening  at  8:30. 


The  Happiness  Boys  are  on  the  air  at 
other  times  during  the  week,  but  they 
can  best  be  "caught"  at  their  regular 
hour  on  Fridays.  Their  programs  con- 
sist of  everything  from  good  natured 
banter  to  beautifully  sung  popular  and 
semi-classical  songs.  They  don't  care 
what  they  sing — and  neither  do  their 
listeners — just  as  long  as  it's  full  of 
happiness.  And,  as  one  old  lady  said 
after  listening  to  "the  boys"  for  the  nth 
time,  "Why,  those  fellows  just  ooze 
happiness." 

To  accomplish  such  a  feat  over  the 
radio  is  indeed  something  to  be  proud  of. 
A  National  Reputation 

AND  although  the  Happiness  Boys 
started  out  to  bring  cheer  to  the 
lives  of  New  Yorkers  in  particular,  their 
cheery  songs  have  reached  to  the  ends 
of  the  continent.  Instead  of  merely  a 
local  reputation,  their  fame  has  spread 
far  and  wide.  They  are  known  as  "The 
Happiness  Team,"  and  so  great  has  their 
correspondence  become  that  WEAF  has 
had  to  instal  a  special  office  for  them. 

Letters  from  spinsters  and  bethrothed 
flappers;  from  Middle  Aged  business 
men  and  youthful  swains;  and  scrawls 
from  children  asking  for  undreamed  of 
favors — such  is  a  sample  of  the  day's 
mail  addressed  to  "The  Happiness  Boys." 

Do  you  blame  them  for  liking  their 
job?  Listen  to  them  at  WEAF  and  be 
happy,  too! 

Happiness  Is  Costly 

HAPPINESS,  although  very  plentiful 
at    WEAF,    is    a    rather    expensive 
thing. 


It  is  now  broadcast  regularly  by  the 
"Happiness  Boys"  at  the  rate  of  ten 
dollars  per  minute.  A  half  hour  pro- 
gram by  them  costs  just  three  hundred 
dollars.  It's  worth  it — surely.  But  the 
radio  fan  who  gets  the  happiness  does 
not  have  to  pay  for  it.  Instead,  the 
company  which  hires  the  boys  finds  it 
worth  while  to  spend  the  sum. 

WEAF,  probably  one  of  the  best  known 
stations  in  the  world,  has  prospered  by 
its  unique  and  original  "pay-as-you- 
broadcast"  system.  It  sells  "microphone 
time"  and  not  one  fan  has  said  nay.  In 
fact,  they  like  it. 

Another  expensive  entertainment  is 
given  by  "Roxy"  Rothafel,  conductor  of 
the  Capitol  Theatre  orchestra.  This 
theatre  pays  about  $600  a  night  for  the 
privilege  of  sending  its  beautiful  music 
through  the  air. 

Although  they  pay  for  their  time,  the 
"Happiness  Boys"  trio  have  become  ex- 
ceedingly popular.  Their  "Silver  Threads 
Among  the  Gold"  can  get  tears  in  the 
same  volume  as  "I  Wonder  Who's  Kissing 
Her  Now"  can  get  smiles.  Every  time 
that  they  leave  the  microphone  it  is  a 
signal  for  radio  fans  to  sit  down  and  write 
into  the  station  with  their  applause  cards. 
The  number  of  these  cards  and  letters 
that  they  get  has  rarely  been  exceeded 
by   any   other   entertainers    of    the    air. 

On  top  of  all  of  WEAF'S  individual 
stars,  however,  stands  the  famous 
Graham  McNamee,  convention  announc- 
er, who  broadcast  the  "play  by  play" 
story  of  the  Democratic  and  Republican 
conventions.  His  resonant  voice  has 
(Turn  to  page  46) 


RADIO  AGE  for  January,   1925 


The  Magazine  (bf  the  Hoi 


29 


The  Hidden  Voice 

How  Some  Radio  Ingenuity  Rescued  a 
Stolen  Baby  and  Sweet- 
ened an  Infant  Temper 


Soured  by  Sore  Gums,  kffi^&fr* 


Seated  tensely 
before  the  micro- 
phone, Jimmie 
sent  out  the  call 
from  the  broad- 
casting station — 
all  programs  were 
stopped  and  the 
air  was  clear  for 
the  cry  for  help. 
Within  a  few  min- 
utes  the  whole 
city  was  aware  of 
the  bold  kidnap- 
ping. 


Chapter  I. 

Radio 
Lullaby 


SISTER  Ella's  baby  had  been  crying 
for  more  than  an  hour,  and  every- 
body in  the  house  was  getting 
nervous.  "Everybody,"  collectively 
speaking,  included  Ella,  Ella's  mother, 
and  her  brother,  Jimmie  Kinney.  They 
were  at  their  wits'  end  to  know  what  to  do. 

These  three  and  the  baby  constituted 
a  family  of  stay-at-homes  from  neces- 
sity. Jimmie's  mother  had  just  had 
all  her  teeth  pulled  out,  and  she  wouldn't 
be  seen-  out  of  the  house  until  her  new 
set  was  finished;  Ella  was  visiting  her 
parents'  home,  and  her  lusty-voiced, 
nine-month-old  Edward  Jerome  Stans- 
bury,  Jr.,  was  so  cross  from  teething 
that  it  was  folly  to  allow  him  to  do  any 
broadcasting  in  the  open  air.  As  for 
Jimmie,  he  was  laid  up  at  home  with  a 
sprained  ankle,  bundled  in  bandages, 
and  the  only  way  he  could  move  about 
with  any  degree  of  comfort  was  with 
the  aid  of  a  crutch 

Jimmie  was  almost  a  man.  Patron- 
izing friends  of  mature  years  addressed 
him  as  "young  man"  when  desiring  a 
pleasant  look  in  return.  But  everybody 
petted  him  with  the  diminutive  of  James, 
and  no  doubt  his  sweetheart,  whenever 
he  should  select  one,  would  perpetuate 
the  habit.  Still  Jimmie  did  not  feel 
diminutive.  He  usually  went  at  things 
in  a  "big  way";  that's  how  he  got  his 
sprained  ankle.  He  tackled  a  half 
back,  half  again  his  weight,  on  the  high 
school  gridiron,  and  something  had  to 
give. 

If  there's  anything  that  will  try  the 
patience  of  a  young  fellow  like  Jimmie, 
it  is  to  be  cooped  up  at  home  with  a 
crying  baby.  And  such  a  fellow  will 
either  fume  and  fret  over  undeserved 
punishment  of  this  sort,  or  he  will  exer- 
cise his  wits  for  relief. 


Some  Radio 
Paregoric 

TIMMIE  did  both.  After  fuming  and 
"**  fretting  for  an  hour  and  making  his 
mother  and  married  sister  miserable, 
he  got  busy  with  his  ingenuity,  gave  the 
baby  a  "dose  of  radio  paregoric,"  stopped 
his  crying,  and  nearly  caused  a  tragedy. 

However,  Jimmie's  treatment  was  in 
no  respect  ill-advised.  It  was  really 
ingenious  and  highly  commendable.  He 
merely  unearthed  his  diminutive  super- 
regenerative  receiving  outfit  from  a 
mass  of  what  a  layman  would  call  "junk" 
in  his  radio  work-shop,  tuned  it  to  re- 
ceive a  musical  matinee  being  broadcast 
for  the  special  benefit  of  afternoon  meet- 
ings of  women's  clubs,  sewing  circles, 
and  ladies'  aids,  and  deposited  it  in  a 
sliding  drawer  under  the  body  of  the 
carriage  in  which  the  baby  lay. 

For  some  reason,  explicable  only  by 
a  teething  pathologist,  the  ruse  was 
successful.  Muffled  under  the  bundle 
of  pillows  and  quilts,  the  music  proved  to 
be  gently  soothing.  Baby  Edward 
became  suddenly  very  still,  then  actually 
laughed,  "goo-ed"  eagerly,  and  began 
to  bite  his  fistful  of  zwieback  with  in- 
dustrious contentment. 

Up  to  this  time  Jimmie  could  not 
induce  a  member  of  the  family  to  listen 
to  a  radio  lecture  by  him,  but  now  he 
had  no  difficulty  in  interesting  his  sister 
in  a  technical  description  of  his  miniature 
receiving  set,  which  he  had  constructed 
himself.  It  had  afforded  a  very  edifying 
substitute  for  some  of  the  "rough  neck" 
pranks  of  high  school  boys  soon  after 


By  FRANK 
HONEYWELL 


its  completion.  It  had  stimulated  some 
real  imagination  among  some  of  the 
usually  "slap-stick"  fun  makers  of  his 
acquaintance,  and  he  and  a  quartet  of 
his  friends  often  indulged  their  mis- 
chievous tendencies  by  conducting  radio 
serenades  under  the  windows  of  girl 
friends  in  the  moonlight. 

Once  they  even  entertained  half  a 
hundred  fellow  passengers  on  a  street 
car  with  a  musical  concert  and  announce- 
ment of  "the  score." 

The  outfit  was  a  "mite  of  a  thing," 
contained  in  a  cabinet  box  about  the 
size  of  a  portable  typewriter  case.  A 
small  loud-speaker,  operated  by  the 
tremendous  amplifying  properties  of  a 
super-regenerative  circuit  carefully  de- 
signed and  assembled,  held  the  secret 
of  the  marvelous  volume  of  signals  which 
it  produced.  The  circuit,  which  is  so 
often  dubbed  a  failure,  had  bowed  sub- 
missively to  Jimmie — for  he  had  mastered 
it  after  many  painstaking  experiments 
in  which  he  endeavored  to  remove  the 
squeals  customary  to  this  type  of  circuit. 
His  labors  bore  fruit,  for  upon  their 
completion  he  had  a  circuit  that  afforded 
volume  obtained  from  a  circuit  that 
amplified  millionfold  with  but  a  single 
tube.  Few  indeed  are  the  successful 
sets  of  this  type — so  critical  are  they. 

At  last  the  baby  went  to  sleep,  and 

Ella    wheeled   the   carriage   out    on    the 

front  lawn,  with  the  muffled  radio  music 

still  playing  softly.     Over  the  open  por- 

(Turn  the  page) 


30 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


Neighbors  gathered  rapidly  at  the 
Kinney  home,  and  in  a  short  time  half 
a  dozen  boys  and  two  men  were  hurrying 
away  in  different  directions  in  search 
of  the  missing  babe.  The  policeman 
came,  made  note  of  a  few  details,  and 

JIMMIE  returned  to  his  radio  work  hastened  away  more  rapidly  than  he 
shop  in  the  basement,  proud  of  his  had  come.  Meanwhile,  Jimmie,  realizing 
brilliant  idea.  Both  mother  and  sister  that  he  could  take  no  active  part  in  the 
complimented  him  effusively  and  went  search,  sat  down  to  rest  his  aching  ankle 
about  their  housework  much  more  cheer-     and  racked  his  brain  for 


tion  she  spread  a  mosquito  net  to  protect 
the  infant  from  flies  and  left  him  in  a 
shaded  spot  to  the  tender  mercies  of 
gentle  zephyrs  of  a  mild  Summer  day. 

His  Fame  Assured 


fully.      Once    Ella    called    down    to    him 
this  blithesome  announcement: 

"I'm  going  to  write  to  all  the  radio 
editors  whose  addresses  I  can  find  and 
tell  them  what  you  did.  It'll  make  you 
famous." 

"Yes,"  Jimmie  agreed;  "they'll  run 
big  headlines,  reading  'Radio  Latest 
Remedy  for  Teething  Babies.  Does 
the     Work    where     Zwieback     Won't.'  " 

Jimmie  had  been  idling  his  time  away 
up  to  the  moment  when  this  bright  idea 
came  to  him.  Now,  however,  he  felt 
much  more  industrious.  With  his  lame 
foot  resting  as  comfortably  as  possible 
on  an  empty  box,  he  sat  at  his  work- 
bench and  began  to  wind  a  set  of  coils 
for  a  new'  low-loss  receiver. 

But  he  had  not 
been  thus  occupied 
long  when  a  scream 
such  as  he  had  never 
heard  before  caused 
him  to  drop  his  work 
and  hobble  upstairs 
as  fast  as  he  could  go 
with  safety.  As  he 
reached  the  living 
room,  Ella  rushed  in, 
weeping  and  wringing 
her  hands  and  crying 
out  that  her  baby 
had  been  stolen.  Her 
mother  followed,  al- 
most as  desperate  in 
words  and  manner. 

"I  had  him  in  the 
carriage  out  i'n  the 
front  yard,  and  some- 
body came  along  and 
wheeled  him  away," 
wailed  Mrs.  Stans- 
bury.  "Oh,  what  will 
I  do?  Jimmie,  can't 
you   do   something?" 

"You  must  be  mis- 
taken," her  brother 
replied.  "Probably 
some  neighbor's  ohild 
wheeled  him  down 
the  street." 

"No,  no,"  returned 
the  distracted  mother. 
"None  of  the  children 
around  here  would  do 
My  Edward  has  been  stolen,  I  know  it 
oh,  I  know  it." 

"We'll  call  the  police,  then,"  said 
Jimmie  going  to  the  telephone  and 
lifting  the  receiver. 

He  got  the  nearest  station  without 
difficulty  and  delivered  his  message. 

"We'll  have  a  man  right  over  there," 
promised  the  desk  sergeant.  "But  all 
of  our  motorcycle  men  are  out  on  special 
calls  and  most  of  the  other  men  are  at  a 
big  fire  that  broke  out  twenty  minutes 
ago.  We'll  take  care  of  you  just  as 
speedily  as  we  can  get  the  men." 


an  idea  that  might  res- 
cue him  from  the  dis- 
grace of  utter  uselessness. 
"I  did  one  smart 
thing  today,  they  tell 
me,"  he  mused.  "Now, 
why  can't  I  think  of 
something  else  to  meet 
this  crisis?  By  Jim- 
miny!"  he  exclaimed  sud- 
denly, as  the  longed-for 
"bright  idea"  actually 
came.  "I  do  believe  it's 
worth     trying.  That 

receiver's  still  in  that 
carriage,  no  doubt,  and 
as   long  as  the   baby  is 


Suddenly  there  came  a  sound,  that  of  a  human  voice,  from  the  carriage. 
Julia  was  nonplused.  The  cries  for  help  continued  at  frequent  intervals,  and 
finally  she  broke  into  a  run,  while  passers-by  gaped  in  amazement. 


thing  like  that. 


being  wheeled  away  in  it,  I  may  be  able 
to  make  that  set  help  to  arouse  suspicion. 
I'm  going  to  try  it." 

A  Thought  in  Time 

JIMMIE  remembered  that  the  radio 
*-*  set  in  the  carriage  had  been  tuned 
to  the  city's  only  broadcasting  station, 
which  was  giving  its  afternoon  concert 
at  that  hour  on  a  360  meter  wavelength. 
Jimmie  happened  to  be  well  in  favor 
with  the  station,  having  done  several 
bits  of  mechanical  work  for  their  operat- 
ing staff  in  times  of  need. 

His    imagination    afire    with    the    pos- 


sibilities of  his  plan,  Jim  hobbled  down- 
stairs, hailed  a  taxi  and  sped  toward 
the  business  center  of  the  town,  where  the 
studio  was  located.  The  antenna  towers 
were  situated  some  ten  miles  from  the 
town,  in  keeping  with  the  latest  ideas 
of  Frederick  Newgard,  owner  of  the 
station,  who  believed  that  radio  towers 
should  be  free  from  the  interference- 
causing  influences  of  a  city.  Arrived  at 
the  studio  build- 
ing, Jim  dashed 
upstairs  only  to 
be  greeted  with  a 
muffled  "shhh!"  as 
he  neared  the 
studio  waiting 
room. 

"No  noise!"  an 
important  indi- 
vidual warned 
him.  "There's  a 
concert  going  on 
now.  Don't  you 
know  any  better 
than  to  come  rush- 
ing in  here  like 
this?" 

Exasperated, 
Jim  told  the  self- 
stylejd  guard  who 
he  was,  with  a 
few  added  imagin- 
ative explanations 
for  good  measure. 
His  words  were 
"open  sesame." 
He  was  ushered 
into  the  studio 
waiting  room  and 
there  word  was 
sent  to  Larry 
Hornaday,  youth- 
ful announcer  and 
director  of  the  sta- 
tion, that  a  young 
friend  was  await- 
ing him  in-unusual 
haste.  After  fin- 
ishing the  an- 
nouncement of  the 
first  number  on 
the  afternoon's 
program,  Larry 
sauntered  out, 
carefully  closing 
the  studio  door, 
and  greeted  Jim. 
"What's  on  your 
mind,  kid?"  he 
queried.  "You 
look  upset.  Blow 
out  eight  tubes  or 
something?" 

"Nope.  I  want 
you  to  let  me  have  your  station  for 
awhile."  Jim  was  almost  too  nonchalant 
to  be  true,  considering  the  importance  of 
his    statement. 

Larry  was  rightfully  surprised.  He 
chuckled  and  asked  Jim  jokingly  if  there 
was  anything  else  he  wanted. 

Then  Jim  got  down  to  business.  He 
outlined  his  plan;  how  the  baby  had 
been  kidnapped  while  in  a  carriage 
equipped  with  a  portable  radio  set  which 
was  tuned  to  the  local  broadcasting 
station. 

"Can't  you   see?"  Jimmie  demanded, 
(Turn  to  page  63) 


RADIO  AGE  for  January,   1925 


What  the  Broadcasters  are  Doing  3 1 


A  Pleasing  VOICE  Isrit  Enough ! 

Says  Owen  E.  McGillicuddy,  Who  Studies  Announcers 


CAtwell  Photo) 

George  Hay,  "Solemn  Old 
Judge"    of  Station    WLS 


A  FAIR  young  daughter  of  Eve,  while 
listening  recently  to  the  conti- 
nental broadcast,  was  heard  to 
remark,  "There  are  all  kinds  of  an- 
nouncers but,  in  my  opinion,  it  is  not  so 
much  the  voice  that  counts  as  what  goes 
with  it." 

The  young  lady  was  right.  Of  the 
many  announcers  heard  nightly,  there 
are  not  more  than  a  dozen  whose  enunci- 
ation and  method  show  a  conscientious 
desire  to  tell  the  public  all  it  wants  to 
hear  in  a  clear,  concise  and  understand- 
able manner. 

If  an  earnest  desire  to  please  his  public, 
blended  with  a  pleasant  voice  and  a 
polite  manner,  were  the  sole  requirements 
of  a  successful  announcer,  Ernest  W. 
Jackson,  director  of  CXRT,  the  Can- 
adian National  Railways  station  at 
Toronto,  would  be  in  the  front  rank. 
But  Jackson  possesses  more  than  a  good 
voice  and  a  pleasant  manner.  He  has 
a  keen  sense  of  his  responsibility  as  the 
vocal  representative  of  Canada's  great 
railway  system,  and  Sir  Henry  Thorn- 
ton, the  able  president  of  the  C.  N.  R., 
could  not  generate  more  enthusiasm  or 
show  more  regard  for  the  public  than  is 
exhibited  when  "Jacksy"  is  giving  an 
oral  demonstration. 

An  Early  Broadcaster 
/~\UR  friend  Jackson  first  saw  the  light 
"  of  day  at  Simcoe,  Ontario,  in  Oc- 
tober, 1890,  where,  without  the  aid  of 
either  a  transmitting  or  receiving  equip- 
ment, his  broadcasting  was  heard  at 
frequent  intervals  by  the  neighbors. 
After  enjoying  farm  life  near  Courtland, 
Ontario,  for  three  .  years  the  family 
moved  to  TiJisonburg  in  1901,  where  he 


(Knight  Photo,  N.  Y.) 

Thomas    A.    Cowan,    Jovial 
Announcer  from  WJY-WJZ. 

attended  public  and  high  school,  and 
matriculated  to  Toronto  University. 

For  five  years  he  served  the  Traders' 
Bank  of  Canada  and  the  Royal  Bank  of 
Canada  in  various  capacities.  In  1916 
he  took  a  trip  to  the  Orient,  and  on  his 
return  in  1917  enlisted  in  the  Royal 
Flying  Corps,  in  which  he  served  in  a 
staff  position  at  Long  Branch,  Deseronto, 
Leaside,  and  Fort  Worth,  Texas.  He 
was  married  in  1917,  and,  in  1919,  on 
being  discharged  from  the  Air  Force, 
joined  the  Treasurer's  Branch  of  the 
Canadian  National  Railway. 

When  the  Canadian  National  Rail- 
ways decided  last  Winter  to  establish 
broadcasting  stations  in  each  province 
of  the  Dominion  and  place  receiving  sets 
on  their  transcontinental  trains,  Jackson 
was  transferred  to  the  radio  department 
and  placed  in  charge  of  Station  CNRT 
at  Toronto. 

The  locomotive  whistle  which  always 
heralds  CNRT's  coming  on  the  air  and 
the  locomotive  bells  which  follow  the 
signing  off,  are  now  as  well  known  as 
Mr.  Jackson's  voice  in  Canada  and 
the  United  States.  There  are  many 
radio  engineers  and  directors  throughout 


CPhoto  by  Lyonde,  Toronto) 

And  Here's  E.  W.  Jackson 
himself,  of  CNRT,  Toronto 


the  continent  who  hold 
that  Jackson  knows 
how  to  interpret  an 
announcer's  relations 
with  the  public  to 
a  greater  degree  than 
any  other  man  depending  upon  his 
vocal  intelligence. 

In  a  recent  conversation  the  popular 
director  of  CNRT  gave  me  his  opinion 
concerning  an  announcer's  responsibility 
to  the  public  and  his  relations  with  radio 
artists  and  the  company  he  represents. 
"An  announcer  should  be  intimate 
without  being  personal,"  he  declared. 
"He  should  be  cultured  without  being 
too  formal,  and  tactful  without  being 
timid.  Humor  has  its  place,  but  there 
is  a  type  of  humor  heard  sometimes 
which  is  violently  offensive  to  all  good 
taste.  While  an  announcer  must  be 
honest  at  all  times,  there  is  never  any 
necessity  for  being  brutally  blunt.  Bru- 
tally blunt  people  never  accomplish  any 
good  in  the  world  and  are  always  ob- 
noxious. 

"An  announcer  should  take  extreme 
care  regarding  the  correct  pronunciation 
of  foreign  names  of  places,"  he  con- 
tinued. 

"While  he  uses  his  imagination,  he 
should  be  neither  artificial  nor  super- 
ficial in  either  the  tone,  inflection,  or 
phrasing  of  his  announcement.  There 
should  always  be  congenial  relations 
between  the  public  and  himself,  and 
though  he  is  heard  often  there  is  no 
reason  why  he  should  be  seen.  In  other 
words,  he  should  become  and  remain  an 
invisible  friend  to  every  home  in  which 
his  voice  enters. 

(Turn  to  page  58) 


32  RADIO  AGE  for  January,  1925 


What  the  Broadcasters  are  Doing 


None  Other  Than  Bert  Davis 

'The  Clown  Jgt^Km^  of  the  Air" 

Leads  in    v  Contest 


Harry 

Aldyne 
Reviews 
The  Votes 


Winner 

of  the  Final 

Contest  to  Get 

Grand  Trophy 


THE  CLOWN  of  the  air"  comes  to  the  fore  to 
prove  that  all  radio  fan's  don't  prefer  serious  music. 
By  receiving  more  votes  in  November  than  any  others 
entrant  in   the  RADIO  AGE  Radio  Favorite  Popularity 
Contest,  the  Clown   of  the  Air,  more  commonly  known  as 
Bert  Davis,  achieves  his  rightful  position   as  King   of  Jazz. 

Bert  has  been  singing  over  Middle  Western  radio  stations 
steadily  during  the  past  few  months.  He  has  traveled  from 
state  to  state  and  "knocked  'em  dead"  wherever  he  went, 
simply  because,  as  one  admirer  put  it,  "He  can  sing  more  crazy- 
things  than  you  ever  heard  before." 

He  ranks  easily  with  such  entertainers  as  Wendell  Hall, 
Banks  Kennedy,  Axel  Christensen,  Art  Linick,  and  others  who 
are  acknowledged  leaders  in  their  respective  lines. 

A  Vod-Vil  Star,  Too 

BERT  is  a  vaudeville  trouper  by  profession,  having  started 
his  stage  career  in  Chicago  for  various  vaudeville  circuits. 
(They  weren't  short  ones,  either.)  When  the  radio  craze  hit 
the  country,  Bert  was  among  the  first  to  recognize  in  radio  a 
vital  means  of  getting  before  song  lovers.  So  he  originated 
his  own  repertoire  and  style  and  started  to  "do  his  stuff." 
He  succeeded,  and  today  his  name  is  a  byword  for  the  liveliest 
in  jazz.  He  has  appeared  at  every  Chicago  radio  station, 
being  most  consistent  at  WTAS,  WGN,  and  KYW. 

He  is  to  appear  regularly  on  RADIO  AGE'S  broadcast  pro- 
grams, after  he  completes  a  recently  inaugurated  vaudeville  tour. 

For  Bert,  like  any  other  true  son  of  the  road,  gets  the  "urge" 
to  appear  before  visible  audiences  once  in  a  while.     But  he 


POPULARITY  CONTEST  COUPON 

Harry  Aldyne,  Contest  Editor, 

RADIO  AGE,    500  N.  Dearborn  St.,  Chicago. 

I  wish  to  cast  ray  vote  for: 

Name  of  favorite _ _ 

Classification _ „ 


Station Date  Heard 

Name  (optional) „ _ 

Address  [optionall 


-d 


always  comes  back  to  the  radio  studios  with  greater 
"wim  and  wigor"  than  ever. 
Bert  has  been  one  of  the  leaders  in  RADIO  AGE'S 
contest  for  the  past  few  months,  and  it  was  because  of 
his  recent  programs  from  Chicago  stations  that  his  popularity 
rose  and  votesfoegan  to  trickle  in  for  him  with  increasing  regu- 
larity. As  a  result,  Bert  swept  aside  all  opposition  during  the 
month  of  November,  that  contest  having  closed  on  October  15. 
Bert  has  a  lot  of  stunts  in  common  with  Gene  Green,  old 
time  vaudeville  star.  This  pair  "stunted"  together  for  a  few 
years,  and  as  a  result  dyed-in-the-wool  vaudeville  fans  of  bygone 
days  can   hardly  tell  the  two  apart — over  radio,   of   course. 

QO  GET  busy,  folks,  and  help  your  favorite  win  the  contest. 
^  In  the  February  issue  of  RADIO  AGE,  we  will  announce 
the  prize  to  be  awarded  the  winner  of  the  Grand  Contest. 
So  every  vote  counts  NOW!  Clip  the  coupon  on  this  page  and 
send  it  in.  Urge  your  friends  to  do  likewise  before  it's  too  late. 
THE  WINNER  FOR  NOVEMBER 

Bert  Davis Entertainer WTAS  Elgin 

WINNERS  OF  PRECEDING  MONTHS 

July _ Duncan  Sisters 

August. _ Bill  Hay 

September „ Karl  Bonawitz 

October H.  W.  Arlin 

STANDING  TO  NOVEMBER  15th 
Name  Classification 

Karl  Bonawitz Organist WIP 

H.  W.  Arlin__ _ Announcer KDKA 

Bill  Hay ..Announcer KFKX 

Bert  Davis _ Entertainer.- WGN 

Duncan  Sisters. . Entertainers KYW 

Lambdin  Kay Announcer. WSB 


J.  Remington  Welsch Organist: _ KYW 

John  S.  Dagget ™. Announcer KHJ 

E.  L.  Tyson _Announcer_-. WWJ 

Jack  Nelson Announcer W J JD 

Ford  &  Glenn. Entertainers WLS 

Harry  M.  Snodgras3- Entertainer-. WOS 

Fred  Smith — Announcer WLW 

Jerry  Sullivan Announcer  EntertainerWQJ 

Hired  Hand Announcer _ WBAP 

Edw.  H.  Smith  Director-Player WGY 

Nick  B.  Harris.- Entertainer KFI 

Wendell  Hall Entertainer.- WDAF 


Where  Heard 
Philadelphia 
Pittsburgh 
Hastings 
Chicago 
Chicago 
Atlanta 
Chicago 
Los  Angeles 
Detroit 
Mooseheart 
Chicago 
Jefferson  City 
Cincinnati 
Chicago 
Fort  Worth 
Schenectady 
Los  Angeles 
Kansas  City 


The  contest  is  by  no  means  won.  Karl  Bonawitz  leads 
Wendell  Hall  by  only  52  votes.  The  scattering  of  votes  over 
so  large  a  field  may  ultimately  elect  a  dark  horse  from  among 
the  many  strong  candidates  whose  names  are  not  even  listed 
on    this    page. 


RADIO  AGE  for  January,  1925 


What  the  Broadcasters  are  Doing 


33 


Wkat  tke 

Broadcasters 

are  Doing 


KYW  Will  Have  New 
Station  in  Chicago 

WESTINGHOUSE  station  KYW  at 
Chicago  is  not  to  move,  but  will 
build  a  new  station  to  be  located  on  the 
roof  of  the  Congress  Hotel,  on  the  shores 
of  Lake  Michigan,  it  has  been  announced. 

This  will  be  a  new  KYW.  The  antenna 
and  tower  will  embrace  science's  latest 
instructions.  Likewise,  the  studio,  which 
will  be  in  the  Florentine  Annex,  Room 
1180  on  the  Parlor  Floor  of  the  Con- 
gress Hotel,  a  large  and  spacious  room, 
will  also  be  constructed  in  the  most 
modern  fashion,  with  accoustics  best 
adapted  for  radio  uses. 

The  equipment  to  be  used  is  of  the 
latest  type  devised  by  the  Westinghouse 
Electric  and  Manufacturing  Company, 
employing  water-sealed  tubes. 

Rectified  alternating  current  will  be 
used,  which  will  change  the  60  cycle 
power  service  to  high  voltage  direct 
current. 

With  the  new  mechanical  equipment 
to  be  used  at  KYW,  a  vast  improvement 
will  be  manifest  over  its  present  station, 
which  already  is  one  of  the  best  in  the 
country. 

Will  Use  Special  Wire 

Programs  from  the  various  studios  will 
be  broadcast  by  special  wire  to  the 
station  on  the  roof  of  the  Congress  Hotel. 

First  comes  the  Balloon  Room  of  the 
Congress  from  which  come  classical 
programs,  renditions  by  the  most  famous 
artists  in  the  world.  It  is  from  here  that 
radio  fans  hear  the  famous  Coon-Sanders' 
Night  Hawks  and  Joska  Debabary's 
orchestras. 

From  the  Florentine  Room  will  be 
broadcast  programs  of  a  popular  nature, 
the  Midnight  Carnivals  each  Saturday 
night — always  a  deluxe  program. 
RADIO  AGE  broadcasts  on  these  mid- 
night shows  the  first  Saturday  in  every 
month. 

From  the  Hearst  Studio:  KYW  will  be 
broadcast  the  usual  afternoon  frolics  on 
Tuesday  and  Wednesday,  the  "At  Home 
Show,"  the  Revue,  and  World  Crier 
service.  This  last  goes  on  the  ether 
every  hour  and  half  hour  throughout 
the  day  and  night. 

The  KYW  studio  in  the  Garrick 
Theatre  Building  will  be  used  for  special 
programs.  Central  Church  goes  on  the 
air  each  Sunday  morning  at  11  o'clock, 
while  the  Chapel  Service  goes  out  at 
2:30  p.  m.,  Sunday  afternoon.  The  Sun- 
day Evening  Club  broadcasts  its  pro- 
grams over  KYW  from  the  Orchestra 
Hall. 


Old  Time  Stage  Star  at 
WSAI 

John  Drury  is  one  of  the  most  popular 
artists  appearing  from  Station  WSAI, 
of  the  United  States  Playing  Card  Com- 
pany, at  Cincinnati. 

Mr.  Drury  is  a  former  well  known  stage 
star,  and  perhaps  several  of  our  elderly 
readers  will  remember  him  for  his  dram- 
atic interpretations  in  days  gone  by.  In 
a  recent  popularity  contest  in  Cincinnati, 
Mr.  Drury  came  out  first. 

At  present  he  is  a  reader  of  well  known 
pieces  from  WSAI,  and  his  services  are 
also  in  demand  at  other  stations  and  from 
dramatic  societies  in  the  Middle  West. 

Mr.  Drury's  photograph  is  reproduced 
in  the  inset  above. 

Mr.  Drury  will  be  glad  tocommmnicate 
with  listeners  who  enjoy  his  programs, 
he  says. 


Have  you  ever  fretted  at  the  "One  Moment, 
Please"  from  broadcasting  studios  while  the  artists 
were  preparing  for  the  next  number?  The  newly- 
developed  microphone  stands  in  the  WLW  studios 
at  Cincinnati  do  away  with  waits  between  numbers. 
Two  signs,  labelled  "Prepare"  and  "Broadcast" 
are  illuminated  as  required  and  there  is  no  loss  of 
time  between  selections,  as  one  microphone  in  the 
studio  is  open  to  "Broadcast"  while  another  in  an 
adjacent  studio  says  "Prepare."  Fred  Smith,  WLW 
director,  is  shown  before  one  of  the  new  "Mikes." 


'Ghost"  Broadcasts  from 
WEEI 

/~\NE  of  the  most  unusual  broadcasts 
^J  ever  transmitted  in  this  country  was 
sent  out  from  WEEI,  the  Edison  Light 
Station,  at  10  o'clock  Hallowe'en  night, 
October  31,  when  a  real  live  ghost  was 
"interviewed." 

This  unheard  of  feature  was  arranged 
by  the  officials  of  WEEI  especially  for 
radio  fans  who  planned  to  put  on 
Hallowe'en  parties.  Nothing  like  this 
broadcast  had  ever  been  attempted 
before,  and  great  preparations  were  made 
to  give  radio  listeners  something  brand 
new  in  radio  broadcasts. 

A  real  haunted  house,  located  several 
miles  out  of  the  city  was  selected  for  the 
stunt.  Special  remote  control  telephone 
lines  were  established  between  the  radio 
station  and  this  house  so  that  when  the 
ghost  walked  the  entire  scene  could  be 
described  to  the  radio  audience. 

The  broadcast  officials  refused  to  di- 
vulge the  location  of  this  haunted  house 
because  they  believed  that  if  they  did  this, 
hundreds  of  sightseerswouldvisitthe place 
and  thereby  interfere  with  the  broadcast. 

At  exactly  10  o'clock  the  telephone  line 
from  the  studio  was  transferred  to  the 
haunted  house  and  from  that  time  until 
the  ghost  appeared  and  disappeared  the 
microphone  was  in  charge  of  "Whit," 
well  known  radio  character.  In  the 
spacious  dining  room  of  this  haunted 
house  a  man  is  said  to  have  murdered 
his  wife  and  two  children. 

All  fans  who  heard  the  broadcast  re- 
ported they  were  actually  "scared"  by  the 
strange,  spooky  sounds  over  the  radio. 

"Santa  Claus  Hour"  at  WLW 

Santa  Claus  has  just  finished  overhaul- 
ing his  airplane  and  will  be  ready  to  read 
the  letters  sent  to  him  from  all  over  the 
country  when  he  arrives  at  the  Crosley 
WLW  broadcasting  Studio,  this  month. 
Santa  Claus  hour  will  begin  at  6 
o'clock  and  this  jolly  patron  saint  of 
childhood  will  be  in  the  studio  Monday, 
Tuesday,  Wednesday  and  Thursday 
evenings.  Who  will  be  the  first  little  boy 
or  girl  to  write  to  Santa  in  care  of  The 
Crosley   Radio  Corporation,   Cincinnati? 

Do  you  remember  the  big  party  at 
Music  Hall  last  year,  with  the  funny 
clowns,  fine  music  and  then  Santa  Claus 
with  his  candy  and  fruit?  Well,  Powel 
Crosley,  Jr.,  has  engaged  the  large  audi- 
torium again  this  year  and  all  the 
children  who  can  possibly  attend  are  ■ 
invited  to  the  big  Christmas  Festival  to 
be  held   Monday  night,   December  22. 

To  the  little  folks  who  cannot  attend, 
there  will  be  the  broadcasting  of  the  entire 
proceedings. 


34 


RADIO  AGE  for  January,  1925 


What  the  Broadcasters  are  Doing 


A  Station  that  Caters  to  Friends 

By  Lera  McGinty 

Inspired  by  "Hired 
Hand"  WBAP  is 
making  life  cheery 
in  the  sunny  south 


FORT  WORTH:— Upon  entering 
Radio  station  WBAP,  at  Fort 
Worth,  Texas,  one  gets  the  unusual 
impression  of  hard  work  and  content- 
ment as  he  encounters  the  announcers 
on  the  job.  It  was  my  good  fortune  to 
find  them  all  present. 

W.  E.  Branch,  program  director  and 
announcer,  simply  radiates  satisfaction 
with  himself,  the  studio  and  the  whole 
world  in  general,  as  he  tips  his  swivel 
chair  back  to  a  dangerous  angle  and 
begins  telling  about  the  virtues  of  WBAP. 
When  asked  if  there  was  any  class  of 
people  it  wished  particularly  to  please, 
he  said,  "Station  WBAP  caters  to  its 
friends — and  has  no  enemies." 

This  remark  incidentally  caused  C.  B. 
Locke,  radio  editor,  to  cease  his  seemingly 
never-ending  task  long  enough  to  slap 
him  on  the  back  and  utter  a  hearty, 
"Spoken  like  a  man,  Bill." 

A  Real  Old-Timer 

TF  THIS  duet  smacks  a  trifle  of  egotism, 
*-  it  is  to  be  pardoned,  considering  that 
Mr.  Branch  is  the  only  one  left  now  of 
the  original  trio,  composed  of  G.  C. 
Arnoux,  E.  L.  Olds  and  himself. 

He  built  the  first  set  used  by  WBAP, 
and  when  it  was  later  equipped  with  a 
Western  Electric,  he  stayed  on  as  radio 
engineer.  Recently  he  has  been  made 
program  director  and  announcer.  He 
not  only  serves  in  this  capacity,  but 
furnishes  entertainment  for  thousands 
of  enthusiastic  fans  with  his  popular 
noon-day  piano  concerts.  He  just  natur- 
ally feels  as  proud  of  the  studio  as  an 
adoring  parent  does  of  a  successful  son. 

Mr.  Locke  joined  forces  with  WBAP 
as  editor  in  November  and  seems  to  have 
been  promptly  submerged  under  a  blan- 
ket of  requests  for  WBAP  acknowledg- 
ment stamps.  Various  attempts  have 
been  made  by  others  to  get  an  interview 
with  him  to  no  avail,  and  so  far  the  most 
I  have  heard  him  say  is:  "No  money 
enclosed." 


"The  Station  with  no  enemies"  is  the  favorite  among  the  southland's  radio 
fans.  In  the  oval  is  a  view  of  the  studio  of  WBAP,  which  has  the  highest 
power  rating  of  any  station  in  the  Southwest.  The  right  portrait  above  is 
W.  E.  Branch,  veteran  announcer  at  WBAP — and  with  his  back  unceremoni- 
ously facing  us,  Mr.  Reader,  is  the  inimitable  and  mysterious  "  Hired  Hand." 


Not  knowing  whether  or  not  he  was 
talking  to  me  and  meant,  "No  money 
involved,"  I  deliberately  reached  across 
his  desk  and  picked  up  the  paper  he  had 
flung  aside  and  found  it  to  be  a  request 
for  a  WBAP  stamp,  and  the  writer  had 
forgotten  to  enclose  the  dime. 

That  was  indeed  a  happy  occasion  for 
me,  because  I  feared  that  he  expected 
to  be  paid  for  an  interview. 

However,  his  fellow  workers  say  he  is 
talkative  when  he  isn't  so  busy,  and  he 
is  certainly  an  addition  for  any  studio 
to  be  proud  of. 

(Whisper,  he  is  good  looking  and  per- 
sonally I  believe  he  is  trying  the  "work 
cure"  on  a  broken  heart  and  that  would 
be  an  interesting  story  if  it  is  so.  I  am 
going  back  again  when  the  rush  is  over, 
and  if  I  find  out  I  will  let  you  know). 

"PVERYBODY  likes  surprises,  that 
-L-'  is  why  I  have  saved  the  best  for 
the  last. 

It  is  the  "Hired  Hand,"  comedian  and 
substitute  announcer.  Of  course,  it  is 
needless  to  say  that  he  is  the  outstanding 
feature  offered  by  WBAP.  To  hear  him 
announcing,  one  would  naturally  draw 
the  conclusion  that  he  has  nothing  else 
to  do  but  think  up  funny  jokes  and  get 


himself  into  tight  corners,  but  when  it 
comes  to  having  nothing  to  do,  it  just 
doesn't  fit  that  individual  at  all. 

He  will  have  to  be  given  credit  for 
being  an  extraordinarily  clever  person 
when  it  is  considered  that  he  toils  daily 
in  the  boiler  room  from  early  until  late, 
trudges  to  and  from  his  boarding  house, 
cleverly  dodging  his  landlady  when 
he  deems  it  necessary — -and  that  is  one 
place  his  good  judgment  never  fails  him, 
he  says — and  besides  attending  to  his 
regular  studio  duties  of  sweeping,  dusting, 
errand  boy  and  sub-announcer,  I  think 
it  will  be  agreed  that  he  is  just  naturally 
"clever." 

He  is  never  heard  to  complain  and  it  is 
only  by  close  discernment  that  one  is 
ever  able  to  catch  a  gleam  of  wistfulness 
in  his  eyes  for  less  work  and  more  pay. 

These  sacrifices  are  not  always  without 
their  recompense,  however.  Almost 
daily  he  is  rewarded  with  one  or  more 
boxes  of  cigars  or  candy,  pecans,  fruit, 
ducks,  and  he  has  been  known  to  even 
receive  packages  of  fried  chicken  and  at 
one  time,  three  live  possums  and  a  porcu- 
pine, (saying  nothing  of  the  mash  notes). 

So  you  see  he  manages  a  rather 
well  balanced  diet  in  spite  of  the  usual 
boarding  house  hash. 


RADIO  AGE  for  January,   1925 


What  the  Broadcasters  are  Doinz  35 


"Why  I  NEVER  SMILE" 

— As  Told  by  a  SAD  but  HOPEFUL  Musical 
Director 


By  CHARLES  H.  GABRIEL  Jr. 


Musical  Director,  Station  WGN. 


TAKING  a  receiving  set  apart  to  find 
out  what  makes  it  tick  has  nothing 
whatever  on  taking  an  "artist" 
apart  to  find  out  what's  wrong  with  the 
picture.  Note  the  quotation  marks 
inclosing  the  word  artist.  It's  always 
the  sort  of  musician  we  describe  with 
"quotes"  that  makes  musical  directors 
tear  out  the  few  wisps  of  hair  remaining 
on  the  old  bean  and  laugh  hysterically. 

Real,  honest-to-goodness  artists  are 
seldom  difficult  to  get  along  with  as  long 
as  you  remember  that  they  actually  are 
famous  or  deserve  to  be.  Used  as  they 
are  to  the  exigiencies  of  concertizing, 
they  appreciate  the  efforts  made  in  their 
behalf  and  know  of  the  vexatious  "little 
things"  that  may  almost  wreck  a  recital 
at  the  last  moment. 
But  the  "artists"! 

Why  a  Musical  Director? 

Everybody  knows  what  an  announcer 
does — everybody  hears  him  doing  it. 
A  pianist's  place  in  the  scheme  of  a 
radiocast  is  pretty  well  defined.  The 
title  of  "publicity  director"  is  self- 
explanatory.  But  what  on  earth  is  a 
musical  director  and  why? 

Well,  he  arranges  the  programs  and 
provides  the  "talent."  Simple,  is  it  not? 
It  is  not,  even  if  we  do  say  it. 

Boiled  down  (!)  the  musical  director's 
job  is  to  provide  some  300-odd  programs 
a  year,  each  requiring  the  services,  co- 
operation and  good  will  of  from  four  to 
twenty  musicians;  to  see  that  everybody 
arrives  in  time  to  "appear"  on  the  dot; 
to  placate  the  wrath  of  the  small-timers; 
to  use  diplomacy  in  the  case  of  perform- 
ers of  fame;  to  accept  the  mean  cracks 
of  those  who  have  no  idea  of  the  machin- 
ery of  radio  programs;  to  get  up  in- 
stanter  the  soft  answers  promulgated  to 
turn  away  the  anger  of  simple,  unofficial 
critics;  to  give  hearings  to  those  who 
would  like  to  sing  or  play  for  the  public; 
to  announce  all  kinds  of  "numbers"  in 
all  kinds  of  languages;  to  perform  himself 
when  somebody  doesn't  arrive  for  the 
show;  to  play  accompaniments  for  those 
who  failed  to  provide  their  own  pianists. 
.  .  .  The  rest  of  the  time  he  has  to 
himself. 

His  Crown  of  Thorns 

T^OR  ways  that  are  hard  and  tricks 
-^  that  are  vain — to  jumble  a  metaphor 
or  two — the  impresario  of  musicians 
wins  the  mothproof  medal.  The  average 
"manager"     of     talent     finds     his     path 


bestrewn  with  tempera- 
ments of  great  variety 
and  curious  design. 

The  late  F.  Wight 
Neumann  and  the 
present  Louis  Eckstein 
of  Ravinia  fame  con- 
firmed that  rumor  to  us 
in  person.  But  whereas 
men  of  their  profession 
are  concerned  with  but 
what  amounts  to  a 
handful  of  concerts 
or  opera  performances 
yearly,  the  radio  direc- 
tor must  scare  up  hun- 
dreds of  musicians  and 
arrange  hundreds  of 
programs.  Not  only 
that,  but  his  audience 
is  multitudinous  and 
supercritical,  whereas 
the  concert  manager's 
patrons  are  fewer  and 
not  so  apt  to  be  rabidly 
critical,  since  only  those 
who  understand  and 
enjoy  this  type  of 
program  pay  him  for 
seats.  They  wouldn't  go  if  they  didn't 
like  the  kind  of  music  the  recital  or  con- 
cert assured. 

The  radio  audience,  on  the  other  hand, 
is  a  cross  section  of  the  population  of  the 
United  States.  Some  like  jazz;  some 
despise  it;  some  dislike  sopranos,  some 
revile  contraltoes;  some  root  for  piano 
solos,  other  say  "bah,"  not  to  say  "blah"; 
some  w-ant  old  time  favorites,  younger 
hearers  cry  for  popular  songs  of  today. 
And  so  it  goes.  Yet  all  these  "critics" 
of  each  other's  tastes  are  listening  to  the 
musical  director's  daily  programs  at  the 
same  time  and  each  type  thinks  the  pro- 
gram is  terrible  if  it  does  not  consist  of 
just  what  it  likes  best. 

Starting  out  in  the  early  morn  intent 
on  catching  the  early  artist  and  "booking" 
him,  the  pale  young  man  with  the  high 
forehead  and  fallen  arches  finds  two 
classes  of  musicians  awaiting  him — the 
kind  that  begs  to  be  put  on  a  program 
and  the  kind  he  has  to  ask  to  do  their 
stuff  for  this  radio  age.  The  former  keep 
the  telephone  wires  sizzling  throughout 
the  day  and  wear  out  the  anteroom  car- 
pet during  "tryout"  hours.  Here  begins 
woe.     Most  of  them  know  they  are  good. 


Charles  H.  Gabriel  Jr.,  of  WGN 

(Drake  Photo) 

But  the  others.  Knowing  they  are 
good,  nine  times  out  of  ten  they  are  in- 
sulted when  the  inevitable  request  to 
hear  them  is  made. 

"Why,"  said  a  young  near-soprano  to 
us  the  other  day,  "Mme.  Screech  says  I 
am  really  too  good  for  the  radio.  She 
says,  everybody  says,  I  have  a  wonderful 
voice.  I  only  want  to  sing  because  so 
many  of  my  friends  who  live  out  of  town 
are  anxious  to  hear  me.  When  can  I 
come?  I  prefer  your  Master  Artist  re- 
citals on  Sunday  and  could  do  a  whole 
hour  for  you." 

What  to  do?  What  to  do?  What  to 
do? 

When  she  finally  consents  to  sing  a 
little  test  song,  the  voice,  what  there  is 
of  it,  is  very  good — only  for  talking,  not 
singing.  To  plainly  say  so  would  not 
be  quite  what  they  are  doing  this  year 
in  the  best  circles.  To  book  her  for  an 
appearance  would  be  a  pitiful  thing  to 
do,  not  only  for  the  reputation  of  the 
station  but  as  an  unnecessary  torture 
to  the  future  hearers.  What  would  you 
say?  What  we  say  is  a  secret  of  musical 
directors. 

Too  recently  a  gentlewoman  was 
Honestly,  most  of  them  are  good  and  booked  by  error  of  confusing  her  with 
dating  them  up  is  merely  a  question  of  another  of  the  same  name,  and  immedi- 
"how  soon  can  you  come?"  (Turn  to  page  67) 


36 


RADIO  AGE  for  January,  1925 


Above  is  Harry  Snodgrass,  during  one  of  his  "at  home"  programs  from  the 
Missouri  State  Penitentiary,  where  he  has  been  confined  for  three  years.  His 
piano  renditions  are  broadcast  regularly  through  Station  WOS,  at  Jefferson  City. 

'  Stone  Walls  do  not 
a  Prison  Make' 

By  RUSSELL  H.  HOPKINS 


"Stone  walls  do  not  a  prison   make,    nor 
iron  bars  a  cage." 

— Old  Saying. 
"Love     laughs     at     locksmiths." 

— A  nother  Saying. 

NO  ONE  knows  the  truth  of  the 
foregoing  sayings  better  than 
Harry  Snodgrass,  who  is  known 
throughout  the  United  States  and  Canada 
as  the  inimitable  "King  of  the  Ivories" 
from  Radio  Station  WOS,  at  Jefferson 
City,  Mo. 

Three  years  ago  this  January,  Snod- 
grass was  an  Unknown — a  mere  cog  in 
the  world's  everyday  life.  And  he  wasn't 
very  successful  at  that. 

Harry    was    somewhat    shiftless    back 


in  1921.  He  couldn't  hold  a  job  for 
more  than  a  month.  He  had  a  wonderful 
gift  of  piano  playing,  but  he  had  no  one 
to  inspire  him.  So  he  drifted  along — 
not  even  a  pebble  on  Life's  beach. 

The  Turning  Point 
TTE  GOT  into  bad  company.  One 
*-*-  night  the  police  made  a  raid  and 
Harry  was  "among  those  present"  when 
charges  of  robbery  were  made.  Harry 
was  tried  and  convicted  on  a  charge  of 
attempted  burglary.  He  was  sentenced 
to  serve  three  years  in  the  Missouri 
State  Penitentiary. 

Most  people  regard  a  prison  as  the 
last  place  to  achieve  fame,  but  Snod- 
grass looks   upon   his  jail   sentence  with 


What  the  Broadcasters  are  Doing 

The  Real 

Story  of  Harry 

Snodgrass,  Who 

Won  Radio 
Fame  in  Prison 


a  feeling  of  gratitude.  For  were  it  not 
for  that  chance  arrest  back  in  1921, 
he  might  still  be  an  unknown  wanderer. 

Not  long  after  his  advent  into  the 
prison,  radio  began  to  win  popularity. 
Broadcasting  stations  sprung  up,  and 
among  them  was  WOS,  at  Jefferson  City, 
Missouri.  While  visiting  the  peni- 
tentiary one  day,  a  representative  from 
WOS  happened  to  hear  Snodgrass  play- 
ing the  piano  casually  and  disinterestedly 
for  a  group  of  prisoners. 

The  radio  man  was  astounded.  He 
marveled  at  Snodgrass'  natural  ability 
as  a  pianist,  his  easy  skill  and  expert 
technique.  The  radio  man  brought 
visiting  pianists  of  note  and  several 
musical  instructors  to  hear  Snodgrass 
play.  All  were  of  the  same  opinion; 
Snodgrass  was  a  "genius  of  the  ivories," 
wasting  his  talents  behind  the  bleak 
walls  of  a  penitentiary. 

J.  M.  Witten,  chief  announcer  and  a 
director  at  WOS,  arranged  to  have  Snod- 
grass broadcast  regularly  from  the 
Jefferson  City  broadcasting  station.  Wit- 
ten  dubbed  him  "King  of  the  Ivories" 
and  advertised  him  on  WOS  programs, 
neglecting,  however,  to  mention  that 
Snodgrass'  studio  was  a  trusty's  parlor 
in  the  state  penitentiary. 

During  the  year  or  so  Snodgrass  has 
been  performing  over  radio,  his  whole 
attitude  of  life  has  changed.  As  he  faces 
the  microphone  in  his  gray  "studio," 
he  visions  the  untold  millions  who  are 
listening  to  his  varied  concerts — jazz, 
classical  music,  and  old  time  favorites. 
He  sees  the  men,  women  and  little  chil- 
dren who  sit  open-mouthed  on  hearing 
his  lightning-like  speed  and  his  tender, 
impassioned  handling  of  the  Old  Masters. 

A  Purpose  in  Life 

CNODGRASS  admits  that  now  he 
^  has  a  purpose  in  life.  The  piano  is 
his  life,  and  now  he  knows  it  will  guide 
him  to  greater  fame  once  he  leaves  the 
confines  of  the  prison  walls. 

"Love  laughs  at  locksmiths,"  he  told 
his  warden.  "I  love  my  work.  When  I 
play  I  am  not  in  prison.  I  am  surrounded 
by  millions  of  admirers  instead  of  four 
gloomy  walls.  If  I  get  so  much  pleasure 
from  playing  now,  can  you  imagine  what 
will  happen  when  I  get  out  of  here?" 

If  Snodgrass  contemplates  fame  now, 
he  does  not  realize  he  has  already  gained 
it.  Few  persons  know  he  is  a  convict, 
but  those  who  know  who  he  is  admire 
him  all  the  more  for  the  change  radio 
broadcasting  has  wrought  over  him;  the 
spiritual  transformation  that  radio  has 
caused  over  this  once  indifferent  "floater." 
(Turn  to  page  69) 


RADIO  AGE  for  January,   1925 


Can 
Beauty 
Be  Sent 

Over 
Radio 


DO  YOU  THINK  it 
possible  to  transmit 
part  of  your  physical 
being  as  well  as  your  voice 
by  radio? 

Byrdetta  Evans,  nation- 
ally known  radio  singer  and 
a  prominent  society  beauty 
as  well,  was  the  person  who 
asked  that  question  at  the 
opening  of  an  informal  inter- 
view over  the  teacups  the 
other  afternoon. 

The  question  proved  to  be  the  first 
and  the  last  to  be  asked  in  said  inter- 
view. In  fact,  it  was  enough  for  a 
whole  interview. 

Assuming  a  very  thoughtful  air,  the  writer 
started  to  quote  several  well  known  radio 
engineers  to  disprove  her  point,  but  Miss 
Evans  assured  him  that  she  was  interested 
in  the  psychological  and  not  the  technical  side 
of  radio. 

"Why?"  we  asked,  coming  to  life. 

"As  you  probably  know,"  Miss  Evans  began, 
"I  have  sung  from  a  large  number  of  broad- 
casting stations  recently,  including  such    well 
known  ones  as  VVGN,  WLS,  WJAZ  and  WEBH.    Of  course, 
I  have  received  my  share  of  letters,  phone  calls  and  telegrams, 
commenting  on  and  praising  my  voice,  as  well  as  requesting 
favorite  numbers. 

Those  Forward  Fans! 

T>UT  the  reason  I  asked  you  that  question  is  because  nearly 
f-f  all  the  messages  from  masculine  fans  not  only  praise  my 
vocal  ability,  but  request  my  telephone  number  or  home  ad- 
dress and  express  a  desire  to  meet  me. 

"I  have  heard  from  many  sources  that  many  movie  stars 
receive  proposals  from  persons  who  have  never  seen  anything 
but  their  image  and  who  have  no  idea  of  their  personality  or 
speech.  But  here  it  is  the  reverse,  for  the  radio  fans  who  write 
me  have  only  heard  my  voice  and  have  no  idea  how  I  look. 

"Naturally,  I  am  considerably  intrigued  by  these  incidents, 
and  I  wonder  if  by  any  chance  my  listeners  could  have  received 
an  impression  of  my  physical  self  along  with  my  voice." 

In  other  words,  Miss  Evans  wants  to  know  if  the  average 
radio  listener  can  tell,  by  paying  rapt  attention  to  a  girl's  voice 


Miss  Byrdetta  Evans 

(Drake  Studio  Photo) 


What  the  Broadcasters  are  Doing  37 

By 
"Buddy 
Snaps  ' 

Who,  After  an 

Interview  with 

Miss  Byrdetta 

Evans,  Feels 

Convinced  that 

Radio  Listeners 

Can  Determine 

Whether  Beautiful 

Singers  Are 

Beautiful ! 


over  the  radio,  whether  she 
is  as  sweet  and  pretty  as 
her  voice  would  have  you 
believe. 

Look  at  Byrdetta! 

TV/TAYBE   there   is  some- 

-'-'-*■   thing   in    her    theory. 

The   reader  will  be  able  to 

solve  this  riddle  by  glancing 

at    the    portrait     of    Miss 

Evans   accompanying    this 

article. 

In    a    moment    of   confidence  Miss 

Evans  showed   us  a  typical  letter  she   received 

after   singing   an    unusually    sentimental    song; 

one    which    undoubtedly     stirred    several     listeners     to 

romantic  ravings — -particularly  the   writer  of  this  billet 

doux: 

"Dearest  Radio  Songbird: 

"I  must  express  my  deep  appreciation  of  your  won- 
derful voice  which  came  to  me  so  marvelously  from 
WGN  last  night.  You  do  not  know  the  solace  and 
comfort  your  song  inspired  in  me.  Why,  I  can  scarcely 
wait  until  your  voice  comes  again  stealing  out  of  the 
night,  bringing  comfort  for  a  lonely  heart.  I  feel  that 
such  a  lovely  voice  could  only  have  its  origin  in  an  equally 
lovely  body. 

"Please  answer  this  message  so  I  may  have  the  privilege  of 
personally  thanking  you  for  your  artistry. 
"Anxiously, 

"George " 

Before  taking  up  her  song  career,  Miss  Evans  was  the  town 
belle  of  Fargo,  N.  D.,  where  she  won  the  annual  beauty  contest 
for  several  seasons.  While  attending  the  University  of  Min- 
nesota she  was  asked  to  enter  a  bathing  girl  contest,  and 
although  her  nearest  approach  to  bathing  exhibitions  during 
past  years  had  been  in  a  railroad  water  tank  near  Fargo,  she 
entered  the  contest  and  was  selected  winner. 

"I  love  radio  for  its  romance,"  Miss  Evans  assured  us.  "No 
one  ever  knows  where  her  voice  is  going  or  to  whom  she  is 
singing.  Wouldn't  it  be  marvelous  to  have  the  Prince  of  Wales 
listening!"  she  sighed,  just  like  any  other  American  girl 
would  at  such  a  supposition. 

But  the  question  still  remains  unsolved — Can  beauty  be 
transmitted  by  radio?    Try  it  and  see. 

(Copyright:  1924:  by  Radio  Abo.) 


38 


RADIO  AGE  for  January,  1925 


What  the  Broadcasters  are  Doing 


How  a  Touch  of 

Radio  Finesse 

t 

Makes  Broadcasting  a 
Pleasure  at  WEBH 

By  WILLIS  ARNOLD 


(Chicago  Aerial  Survey  Fboto.) 
A  bird's-eye 
view  of  the  Edgewater 
Beach  Hotel,  home  of  WEBH. 


FINESSE!  Art!  Color! 
Those   are  three  things   that  the 
Radio  broadcasting  field  is  destined 
to  possess  some  day,  but  which  it  lacks 
to  a  noticeable  degree  at  present. 

Eight  out  of  ten  of  our  broadcasting 
stations  are  the  most  uninteresting  things 
in  the  world.  Artists  "dated"  to  appear 
for  the  first  time  before  the  microphone 
go  to  the  studios  with  hearts  aflame, 
dreaming  wild  dreams  of  the  romance 
and  thrill  they  will  get  from  their  first 
broadcast. 

Instead  of  the  romance  they  had 
supposed  was  behind  the  microphone 
and  the  broadcast  studio,  they  usually 
find  a  dull  and  overheated  room;  a  few 
disinterested  persons  in  charge;  and  a 
mechanical  way  about  doing  things  that 
breeds  "stage  fright"  and  many  times 
causes  a  promising  artist  to  fail  com- 
pletely. 

Mind  you,  not  all  stations  are  like  that. 
But  the  majority  of  them  are.  They 
feel  that  because  a  broadcast  studio  can- 
not be  seen,  it  need  not  cater  to  the 
artistic,  the  colorful  and  the  romance 
that  is  in  radio  as  a  science.  In  other 
words,  the  finesse — the  finishing  touch — ■ 
is  lacking. 

A  Step  Forward 
'"PHE  Edgewater  Beach  Hotel,  one  of 
Chicago's  most  pretentious  show- 
places,  purchased  Radio  Station  WEBH 
with  the  avowed  intention  of  forming  a 
studio  that  would  inspire  radio  artists 
instead  of  terrify  them;  that  would  make 
them  feel  at  home  and  arouse  all  that 
was  artistic  in  them.  The  Hotel  manage- 
ment wanted  class  to  pervade  throughout 
every  inch  of  its  studio. 


The  Hotel  already 
had  something  to 
build  from.  It  had  a 
crystal  radio  studio 
situated  in  a  cozy  cor- 
ner of  the  hotel  building; 
a  st  udioenclosed  entirely  in 
glass  and  built  along  the  lat- 
est lines  of  studio  development. 
The  mechanical  side  of  the 
station  was  acknowledged  one  of 
the  best  in  the  country;  the  operating 
staff  was  the  most  efficient  that  could 
be  found.  The  original  apparatus  had 
communicated  daily  with  Capt.  McMil- 
lan during  his  explorations  in  Arctic 
regions.  These  experiments  were  carried 
on  when  the  station  was  under  another 
management. 

Everything  was  ready,  then,  for  the 
final  step;  the  introduction  of  the  elusive 
bit  of  finesse. 

Robert  D.  Boniel,  a  veteran  at  the 
gentle  art  of  studio  management,  was 
chosen  to  take  charge  of  the  newly 
created  Station  WEBH.  That  was  four 
months  ago.  And  today  WEBH  is  the 
last  word  in  "artistry"  in  radio  broad- 
casting.    Just  as  the  Hotel  itself  strives 


The  famous  Langdon  Brothers,  Hawaiian 
guitar  artists  who  appear  exclusively  on 
WEBH  programs.  They  are  known  from 
Coast  to  Coast  for  their  unique  presenta- 
tions. 


to  cater  to  the  best  tastes  of  Chicago's 
elite,  so  has  "Bob"  Boniel  injected  a 
colorful  atmosphere  in  the  studio  he 
manages. 

Unique  Crystal  Studio 

'T'HE  studio  consists  of  two  glass  com- 
partments. One,  a  very  small  room, 
houses  the  announcer — Mr.  Boniel — and 
his  operator.  The  other  room,  also  glass 
enclosed  and  adjacent  to  the  operating 
and  announcing  room,  houses  the  artists 
in  charge  of  Dean  Remick,  musical 
director.  To  avoid  timidity  on  the  part 
of  the  entertainers  who  view  the  micro- 
phone for  the  first  time,  the  microphone 
is  concealed  in  a  piano  lamp,  and  singers 
and  other  performers  sing  "at"  the  lamp, 
thus  making  it  unnecessary  for  them  to 
concoct  any  weird  illusions  about  the 
powers  of  the  more  or  less  harmless 
microphone. 

Velvet  drapes  further  enhance  the 
beauty  of  "the  crystal  studio"  and  add 
to  its  sound  values.  The  broadcasting 
antennae  are  located  nearly  a  block  away 
from  the  studio  itself,  free  from  interfer- 
ence of  steel  girders.  The  Hotel  is  situa- 
ted in  Chicago's  fashionable  North  Side. 

One  of  the  most  renowned  features  of 
WEBH  and  a  typical  example  of  its 
finesse  is  the  Sunday  afternoon  twilight 
musicale.  Operatic  selections  by  Dan 
Russo  and  Ted  Fiorito's  Oriole  Orchestra 
attract  a  gathering  of  socially-elect  every 
Sunday  at  5  p.  in.;  and  a  famed  singer, 
sometimes  a  soprano,  and  at  others  a 
tenor  or  baritone,  also  appear  on  these 
musicales,  as  an  added  feature.  The 
best  in  opera  music  and  classical  selec- 
tions is  broadcast  on  this  special  program. 

But  that  is  not  all.  Mr.  Boniel's  forte 
is  variety;  and  he  can  arrange  jazz  pro- 
grams with  the  same  success  that  greets 
his  handling  of  classical  arrangements. 
But  Mr.  Boniel  has  the  gift  of  making 
jazz  presentations  seem  ethereal;  he  is 
like  Paul  Whiteman  in  that  respect. 

RADIO  AGE  broadcasts  from  the 
crystal  studio  once  a  month,  the  next 
program  being  scheduled  for  Tuesday, 
December  23,  between  9  and  10  p.  m. 
Tune  in!     Wavelength,  370  meters. 

WEBH  is  continually  hanging  up  dis- 
tance records.  It  is  one  of  the  two  strong- 
est stations  in  the  Chicago  territory,  but 
in  spite  of  the  force  behind  its  broadcasts, 
the  modulation  is  practically  perfect.  This 
is  accomplished  only  by  close  observation 
by  an  expert  corps  of  operators. 


RADIO  AGE-  for  January,   1925 


What  the  Broadcasters  are  Dot 


39 


"Eddie"  Borroff, 
popular  announcer 
of  KYW's  Congress 
Hotel  studio,  from 
which  RADIO  AGE 
b  roadcasts  j  azz 
carnivals  the  first 
Saturday  in  every 
month. 


Radio  Age  to  Try  for 
Distance  from  KYW 

All-Star  Program  to  Be  on  the  Air  at 
Midnight,  January  3,  1925 


strains  of  "How  planning  a  long  distance  test  of  its  pro- 
do   you  do?"  at  2:30  gram  from  KYW  on  Saturday,  January 
a.  m.,  there  was  something  3,  from  midnight  to  2  a.   m.     Prizes  to 
doing  every    minute.  be    announced    over    the    radio    will    be 
Encouraged   by  this  success,  RADIO  awarded  the  first  ten  listeners  who  report 


RADIO  AGE'S  midnight 
show.   What   she  doesn't 
know  about   syncopation 
n't  worth  knowing. 

(CoUbrito  Photo-, 


FROM   coast    to 
coast!      From 
Gulf  to    Canad 
ian  Frontier!    That   was 
the  record  set  by   Station 
KYW     Saturday     evening, 
November   8,    when     RADIO 
AGE    broadcast   its  first  Congress 
Hotel  Jazz  Carnival  from  KYW,  between 
the  witching  hours  of  midnight  and  2:30 
a.  m. 

Although  the  hour  was  late,  it  was  sur- 
prising how  many  fans  managed  to  stay 
up  throughout  the  land.  The  program 
was  as  varied  as  it  was  excellent,  and  a 
corps  of  telephone  and  telegraph  oper- 
ators was  kept  busy  for  two  hours  during 
the  program  and  for  three  days  later 
checking  up  on  the  requests  and  inquiries 
at  RADIO  AGE'S  initial  effort  at  jazz 
broadcasting. 


They're  Off! 

Managed  by  the  able  hand  of  Edwin 
Borroff,  announcer  of  the  Congress  Hotel 
Studio  of  KYW,  the  program  started 
at  midnight  on  the  dot,  with  Coon  San- 
ders' Original  Night-Hawks'  orchestra 
from  Kansas  City.  Then  Banks  Kennedy, 
RADIO  AGE's  original  song  man,  started 
to  tickle  the  keys,  and  from  then  on 
there  was  no  surcease  from  jazz.  From 
the  first  strains  of  Kennedy's  latest  com- 
position,   "Harold   Teen,"   to   the   dying 


AGE  presented  another  of  its  month- 
ly popular  programs  from  KYW  on 
Saturday,  December  6, 
rom  the  same  studio. 
This  time  the  star  per- 
formers were  Banks 
Kennedy,  with  an 
entirely  new  re- 
pertoire; Art 
Linick,  the 
famous  "Mrs. 
Schlagen- 
of 
W 


Here's  "Mrs.  Schlag- 
enhauer,"    without  the 
skirts.     Art    Linick    is 
of  radio's    most 
popular      characters.    /. 
His      interpretations 
are    known      from 
Coast  to  Coast. 

(Celebrity  Photo) 


(by  telegram,  telephone  or  letter)  the 
greatest  distance  reception. 

This  will  be  the  first  time  KYW  has 
attempted  long-distance  tests  for  some 
time,  and  because  of  the  fact  that  an 
unusual  effort  will  be  made  to  cross  two 
oceans,  the  program  will  be  unusually 
attractive. 

Of  course,  there  will  be  Art  Linick, 
with  his  inimitable  renditions  of  quaint 
songs;  Axel  Christensen  will  pound  the 
keys  in  his  airy  style;  and  Banks  Kennedy 
and  Wanda  Goll  will  introduce  the  latest 
in  popular  melodies. 

In  addition  there  will  be  other  head- 
liners.  Tune  in  on  Saturday,  January 
3,  at  midnight,  and  hear  what  Announcer 
Borroff  has  to  say! 

And  if  you  live  at  a  distance  from 
KYW,  send  in  your  report  of  the  program 
for  confirmation  and  win  one  of  the 
prizes! 

By  the  way,  if  you  really  like  RADIO 
AGE'S  broadcast  entertainers,  drop  us  a 
ine  telling  your  appreciation.  And  if  you 
have  any  suggestions,  we'll  be  glad  to 
comply  with  them. 


The  demure  young  lady  below 
is  Claiborne  Foster,  winsome 
heroine  of  "Applesauce."  She  will 
soon  appear  on  a  RADIO  AGE  radio 
playlet  from  KYW  with  Alan 
Dinehart,  her  leading  man. 

(Wide  World  Photo) 


Christensen,  president  of  the  Christensen 
School  of  Popular  Music  and  the  "Czar 
of  Rag-time";  Wanda  Goll,  the  popular 
vaudeville  artist  and  radio  jazz  enter- 
tainer; and  Rose  Marie  Meyers,  who  can 
sing  classical  and  popular  selections  with 
equal  dexterity  and  allure. 

Distance  Test  Planned 
Armed    with    this    group    of    infallible 
radio     artists,     RADIO     AGE     is     now 


40  RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


HYANHATTAN 

f  ELECTRICAL  SUPPLY  COJNC. 

MAKERS  OF  THE  FAMOUS 


0manhattan 
s^Junior  $IO 

LOUD    SPEAKER 


Oldest  and  Largest  Distributors  of 


NEW  YORK 


114  SO.  WELLS  ST.,  CHICAGO 

ST.  LOUIS  SAN  FRANCISCO 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour  41 


The 


Improving  a  Popular  Circuit 

"99"  Reflex  with  Two  Stages 

By  JOHN  B.  RATHBUN 


ACCORDING    to    the    reports    sent 

Zjk      in    by    many   of   our  readers,  the 
J-  •*-  "99"     Tuned     Impedance     Reflex 
has  proved  to  be  one  of  the  most  stable  of 
the    reflex     circuits 
RADIO  AGE. 

It  seems  to  be  less  critical  in  regard  to 
the  varying  inductance  values  of  the 
different  makes  of  audio  transformers  and 
therefore  there  is  correspondingly  less 
trouble  in  adjusting  the  bypass  con- 
densers than  with  other  reflex  types. 
We  have  had  a  great  many  complimen- 
tary letters  on  the  single  tube  "99" 
Tuned  Impedance  Reflex  described  in 
our  April  issue,  and  for  this  reason  the 
writer  resolved  to  expand  this  set  into  a 
three  tube  affair  having  a  still  better 
range  and  much  greater  volume. 

At  first,  the  idea  was  to  reflex  all  three 
tubes,  thus  attaining  three  stages  of  radio 
frequency  amplification  and  two  audio 
amplification  stages,  but  on  actual 
trial  the  circuit  became  so  complicated 
that  I  became  rather  doubtful  about 
suggesting  such  a  hook-up  for  beginners. 
With  all  three  tubes  reflexed,  we  attain 
wonderful  volume  and  range  but  at  the 
expense  of  several  rather  critical  adjust- 
ments which  would  probably  keep  the 
technical  department  of  RADIO  AGE 
in  hot  water  for  several  months  to  come. 

As  a  result  of  many  trial  hook-ups, 
it  was  finally  decided  to  place  one  stage 
of  tuned  radio  frequency  ahead  of  the 
single  tube  "99"  circuit  for  distance,  and 
then  to  add  one  stage  of  audio  for  in- 
r.reasedjvolume.  This  combination  works 
out  very  nicely  and  is  only  slightly  in- 
ferior to  the  circuit  in  which  all  three 
tubes  are  reflexed.  It  is  equivalent  to 
two  stages  of  radio  and  two  stages  of 
audio  amplification  and  compares  very 
favorably  with  a  five  tube  neutrodyne, 
when   properly  built. 

One  more  desirable  feature  in  addition 
to  the  greater  range  and  volume  is  the 
selectivity.     We  can  get  through  almost 


Copyright:    1924 


How  3   Tubes  Will 

II.       L11V<      1I1UJL      .^lill'JV.        1H  . — ..  — _  | — »  a    VU1U  L1IV.  llll'l  IM'l^V     ,"■  IllllVll^llt  111  lilt 

yet     published    by     \J  IV  €      Lj€ttCr     l\Cin2€  three  element  tube  detector,  I  have  shown 

*-*  the  two  element  tube  in  this  role,  which 


tors.  However,  to  avoid  the  several 
drawbacks  for  which  the  crystal  detector 
is  responsible  and  at  the  same  time  to 
avoid    the    tube   noises   inherent    in    the 


any  local  jam  and  bring  in  distance  by 
virtue  of  the  three  controls,  and  in  this 
respect  it  is  one  of  the  sharpest  tuning 
sets  I  have  yet  worked  with.  In  addition 
to  the  original  two  controls  we  have  the 
tuned  radio  frequency  unit  which  sharp- 
ens up  the  set  to  a  point  where  we  bring 
them  in  and  out  on  a  feather  edge.  Ver- 
nier condensers  must  be  used  for  this 
reason  on  all  of  the  stages. 

As  with  all  ordinary  reflex  circuits, 
a  crystal  can  be  used  successfully  as  a 
detector  and  its  use  brings  that  clear, 
clean  tone  that  is  an  impossibility  with 
sets    using   oscillating   type    tube    detec- 


KEEPING  UP  WITH  THE 
LATEST  IN  RADIO 

The  RADIO  AGE  blueprints 
are  the  latest  in  radio  develop- 
ment. They  describe  graphic- 
ally and  clearly  every  step  to  be 
taken  in  the  construction  of  the 
season's  most  popular  circuits. 
The  careful  radio  fan  cannot 
afford  to  be  without  them. 

The  RADIO  AGE  ANNUAL 
for  1925  contains  a  32-page 
blueprint  section  that  will  be 
treasured  by  every  home  radio 
builder.  Sixteen  pages  of  this 
unusual  section  will  consist  of 
real  blueprints — the  kind  that 
have  made  the  RADIO  AGE 
blueprint  section  the  talk  of  the 
radio  world. 

Order  your  RADIO  AGE  AN- 
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is  non-oscillating  and  which  gives  the 
same  pure  tone  as  the  crystal.  These 
"Fleming  Diode  and  the  Tu  Valves" 
eliminate  the  necessity  of  frequent 
crystal  adjustment  and  at  the  same  time 
give  slightly  increased  volume.  These 
tubes  are  simple  and  cost  hardly  more 
than  a  good  crystal  detector.  Three 
element  tubes  should  not  be  used  for  the 
detector  unless  range  is  to  be  attained 
at  the  expense  of  tone. 

Circuit  in  Detail 
T^IGS.  1-2  show  the  circuit  of  the 
■*-  three  tube  "99"  Reflex,  Fig  1  being 
a  picture  diagram  while  Fig.  2  is  a  con- 
ventional diagram  with  the  various 
parts  denoted  by  symbols,  the  latter 
being  of  use  to  the  more  experienced 
builder  who  wishes  to  trace  out  the  func- 
tioning of  the  circuit.  Fig  3  is  an  iso- 
metric view  showing  the  appearance 
from  the  back  of  the  panel  and  the  general 
arrangement  of  the  apparatus,  but  should 
not  be  used  exclusively  for  hooking  up 
the  set  as  several  of  the  wires  are  con- 
cealed behind  the  various  units. 

On  examining  Fig.  1  or  Fig.  2  we  see 
that  two  common  air  core  radio  trans- 
formers or  "neutroformers"  (RFT-1) 
and  (RFT-2)  are  used  for  coupling  the 
R.  F.  stages.  They  are  preferably  tuned 
by  the  17  plate  (0.00035  mf)  condensers 
(CI)  and  (C2)  of  the  vernier  type. 

Right  here  I  see  a  deluge  of  mail 
coming  in  with  the  question  "Can  I 
use  23  plate  condensers?"  You  can  use 
the  larger  condensers  but  you  will  find 
that  the  range  of  wavelengths  is  covered 
over  a  shorter  arc  of  the  dials,  and  hence 
the  tuning  is  made  more  difficult  and 
critical.     This  is  the  only  objection  to  the 


(Turn  to  page  48) 
Blueprints  of  The  Tuned  Impedance  Reflex  with  Two  Stages  on  Pages  42  and  47. 


lis! 

sis? 


J*J  N  -^  a  kj  » 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


43 


No  Frills,  But  Real  Service  With 

A  Tuned  Plate  Regenerative  Set 

By  JOHN  B.  RATHBUN 


PROBABLY  one  of  the  most  effective 
types  of  straight  regenerative  cir- 
cuits and  the  simplest  to  build  is 
the  "tuned  plate"  type  in  which  the 
plate  circuit  is  tuned  to  resonance  with 
the  grid  circuit  by  means  of  a  variable 
inductance  such  as  a  variometer. 

While  I  do  not  present  this  well  known 
circuit  as  anything  new  in  its  entirety, 
yet  by  the  use  of  an  aperiodic  coupler 
I  am  sure  it  is  far  more  selective  than  the 
older  arrangement  with  a  variocoupler 
and  that  it  is  far  easier  to  tune.  With  a 
single  stage  of  audio  amplification  as 
shown  in  the  following  blueprints,  it  is 
an  exceedingly  good  DX  set  and  gives 
good  volume  on  distant  stations.  The 
same  tuner  coil  and  the  same  variometer 
can  be  used  as  was  specified  with  the 
Baby  Heterodyne  II. 
I  Fig.  1  is  a  "picture  diagram"  of  the 
circuit  arranged  for  the  use  of  the  begin- 
ner. In  Fig.  2  is  a  schematic  diagram 
by  which  the  action  of  the  circuit  can 
be  more  easily  traced  out  by  those  exper- 
ienced in  handling  symbolic  diagrams. 
In  the  following  description  we  will 
refer,  therefore,  particularly  to  Fig.  2, 
although  all  three  views  bear  the  same 
reference  numbers  and  figures.  By  this 
system  of  lettering,  the  novice  can  trace 
back  and  forth  between  the  two  diagrams 
and  thus  become  acquainted  with  the 
conventional  symbols  which  mean  so 
much  to  the  experienced  radio  man. 

How  to  Increase  Range 

TO  BEGIN  with,  in  every  type  of 
straight  regenerative  circuit,  some  of 
the  amplified  plate  energy  is  fed  back 
into  grid  or  input  circuit  of  the  tubes, 
thus  increasing  the  potential  acting  on 
the  grid  of  the  tube  and  increasing  the 
range  and  signal  strength  of  the  circuit. 
For  example,  the  feeble  little  impulse 
induced  by  a  distant  station  in  the  aerial 
enters  the  antenna  binding  post  (ANX), 
passes  through  the  primary  coil  (LI)  and 
thence  to  ground  through  the  ground  post 
(GND)  and  the  dotted  ground  wire. 
That  is,  the  antenna  current  of  the  station 
to  which  the  set  is  tuned  passes  to  earth 
in  this  manner,  the  remaining  waves 
from  other  stations  being  "choked  back" 
by  the  self-inductance  of  the  system 

While  passing  through  the  primary 
coil  (LI)  ,the  current  sets  up  a  slight 
magnetic  field  which  threads  its  way 
through  the  turns  of  the  adjacent  sec- 
ondary coil  (L2)  of  the  tuner  and  "in- 
duces" or  creates  a  current  in  (L2).  The 
induced  current,  known  as  the  "secondary 
•current"  acts  on  the  grid  of  the  tube 
through  the  grid  condenser  (CG)  and 
leak  (GL),  thus  causing  the  relatively 
powerful  local  battery  current  to  flow  in 
step  with  the  pulsations  in  the  aerial. 
In  effect,  the  tube  is  now  simply  a  form 
of  current  relay  or  valve  by  which  a 
feeble  pulsating  current  controls  a  rela- 


Attaining  Selectivity 
With  An  Aperiodic 
Coupler  Added  To  a 
Well  Known  Circuit 


tively  much  more  powerful  battery  cur- 
rent in  the  same  way  that  a  slight  move- 
ment of  the  hand  on  the  throttle  regulates 
a  powerful  steam  engine  or  heavy  stream 
of  water. 

Inductance  is  Varied 

By  means  of  the  variable  condenser 
(CI)  the  inductance  of  the  coil  (L2)  is 
varied  so  that  the  circuit  can  be  tuned  or 
brought  into  step  with  the  frequency  of 
the  desired  station.  Coil  (L2)  by  acting 
inductively  on  (LI)  allows  only  the 
current  of  the  desired  frequency  to  pass 
to  earth.  The  number  of  turns  of  wire 
on  (L2)  and  the  capacity  of  the  con- 
denser (CI)  determine  the  frequency  of 
the  circuit  or  the  wavelength  to  which 
it  may  respond.  Increasing  the  number 
of  turns  on  (L2)  or  increasing  the  capacity 
of  (CI)  increases  the  wavelength  of  the 
circuit.  In  the  same  way,  cutting  down 
the  number  of  turns  or  the  capacity  of 
condenser  (CI)  lowers  the  wavelength 
of  the  system.  As  it  is  far  easier  to  vary 
the  capacity  of  (Cl)  than  to  alter  the 
number  of  effective  turns,  the  number  of 
turns  on  (L2)  is  fixed  at  some  value  so 
that  the  operation  of  (Cl)  will  cover  the 
complete  band  of  broadcasting  wave- 
lengths. The  number  of  turns  on  (LI) 
is  not  of  so  much  importance  in  this 
respect,  but  in  any  case  the  turns  on 
(LI)  are  only  a  small  fraction  of  those  on 
(L2). 

Tubes  or  Crystal? 

TF  WE  were  to  depend  completely  upon 
■*-  the  signals  produced  in  this  way,  the 
vacuum  tube  would  not  be  so  very  much 
more  effective  than  a  crystal  detector 
for  the  reason  that  the  potentials  acting 
on  the  grid  of  the  tube  are  very  feeble 
and  the  amount  of  battery  current  con- 
trolled would  be  correspondingly  small. 
The  "amplification"  or  "multiplication" 
of  the  tube  would  not  be  sufficient  to 
give  us  the  tremendous  distance  and 
signal  strength  attained  by  the  tube 
when  used  in  a  "regenerative"  circuit. 
As  matters  stand  at  this  point,  the 
relayed  battery  current  from  the  "B' 
battery  (B)  passes  through  the  plate 
circuit  (12-13)  from  the  positive  side 
of  the  battery  (  +  ),  through  the  phones 
(PH)  and  back  to  the  tube  plate  at  (P). 
Inside  the  tube  this  current  flows  through 
the  vacuous  space  between  the  plate 
(P)  and  the  filament  (F)  and  returns  to 
the    negative    side    (— )    of    the  battery 


through  the  wires  (9-15).  Each  change 
in  the  rate  of  flow  in  this  circuit  moves 
the  diaphragms  of  the  phones  (PH)  and 
thus  produces  a  sound. 

As  the  grid  (G)  of  the  tube  is  between 
the  plate  (P)  and  filament  (F),  it  acts 
like  a  valve  on  the  current  flow.  When 
the  aerial  current  induces  a  negative 
charge  on  (G),  the  current  flow  is  in- 
stantly checked.  When  the  incoming 
signal  imparts  a  positive  charge  to  (G) 
then  the  rate  of  flow  is  increased.  Each 
one  of  these  changes  in  the  n*te  of  flow 
causes  movements  of  the  head-set  dia- 
phragms in  proportion  to  the  intensity 
of  the  incoming  waves.  During  this 
process  of  amplification,  the  incoming 
waves  are  "rectified"  or  checked  so  that 
only  waves  of  like  polarity  pass  through 
the  tube.  This  rectification  makes  it 
possible  to  develop  the  "modulation" 
or  voice  frequency  waves  upon  the 
phones,  as  the  frequency  of  the  radio 
frequency  waves  is  far  too  high  to  cause 
diaphragm  movement. 

Thus  the  tube  acts  in  two  roles.  In 
the  first  place  it  amplifies  the  incoming 
signal  waves,  and  (2)  the  tube  rectifies 
these  waves  so  that  the  voice  frequency 
impulses  are  developed  in  the  phones. 
We  are  not  directly  concerned  with  the 
rectification  factor  at  present  in  describ- 
ing the  regenerative  circuit;  hence  we 
will  let  this  matter  drop  and  consider 
only  the  means  of  amplification. 

Named  according  to  the  tube  elements 
with  which  they  are  connected,  we  have 
the  grid  circuit  at  (6-4-L2-7-8)  and  the 
plate  circuit  at  (11-VA-12-13-14-9-15-F). 
The  grid  circuit  is  the  "input"  of  the  tube 
while  the  plate  circuit  is  the  amplified 
"output."  As  the  current  in  the  plate 
circuit  is  very  much  heavier  than  that 
in  the  grid  circuit,  it  is  evident  that  the 
output  could  be  further  increased  if  we 
could  feed  some  of  the  plate  current 
back  into  the  grid  circuit  for  re-amplifica- 
tion in  the  tubes. 

Thus,  the  plate  current  could  be  am- 
plified a  second  time  with  corresponding 
increase  in  the  output,  and  this  is  ex- 
actly what  is  done  with  the  "feedback" 
type  of  regenerative  circuit.  In  one  type, 
the  conductively  coupled  regenerative, 
the  plate  (P)  is  directly  connected  to  the 
grid  circuit  as  at  (4)  or  to  the  aerial  cir- 
cuit wire,  (2).  In  another  type,  the 
plate  current  is  led  through  a  "tickler" 
coil  which  acts  inductively  on  the  sec- 
ondary coil  (L2). 

In  the  present  "tuned  plate"  regenera- 
tive, the  feedback  is  "capacitative"; 
that  is,  the  plate  current  is  fed  into  the 
grid  circuit  through  the  internal  capacity 
of  the  tube,  control  being  had  by  means 
of  the  variable  inductance  or  variometer 
(VA.)  It  will  be  seen  from  Fig.  2  that 
the  grid  (G)  and  the  plate  (P)  are  like 
the  plates  of  a  condenser  in  regard  to 
(Turn  to  Page  46) 


Blueprints  of  the  Tuned  Plate  Regenerative  on  Pages  44  and  45. 


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46 


RADIO  AGE  for  January,  1925 


A  New  Twist  to  the  Tuned 
Plate  Regenerator 

( Continued  from  page  43) 
each  other,  and  therefore  grid  current 
can  be  fed  into  the  plate  circuit  or  plate 
current  can  be  fed  into  the  grid  circuit 
through  the  capacity  of  this  condenser, 
providing  that  the  two  circuits  are 
brought  nearly  into  step  or  "resonance" 
with  each  other. 

The  inductance  of  the  variometer 
(VA)  is  varied  until  the  grid  and  plate 
circuits  are  nearly  in  resonance,  and  when 
this  is  attained,  plate  current  feeds 
across  (P)  and  (G)  into  the  grid  circuit, 
producing  "regeneration."  This  causes 
a  tremendous  increase  in  the  output  of 
the  circuit  with  corresponding  increases 
in  range.  Without  regeneration  the 
ordinary  range  of  the  tube  would  prob- 
ably be  between  50  and  100  miles.  Adopt- 
ing the  regenerative  principle  makes 
1,000  miles  an  ordinary  range  on  voice 
transmission  and  even  2,000  miles  is  not 
unheard  of. 

Units  and  Dimensions 

TVFOW  we  will  get  down  to  the  practical 
-1-  '  description  and  give  specific  instruc- 
tions for  the  building  of  this  receiver. 
We  can  now  include  the  picture  diagram, 
Fig.  1,  and  the  isometric  view  of  Fig.  3, 
which  shows  the  general  arrangement  of 
the  apparatus  behind  the  panel.  With 
the  exception  of  the  aperiodic  coupler 
(L1-L2)  all  of  the  apparatus  is  standard. 
There  is  nothing  at  all  critical  about  the 
set  and  even  the  inexperienced  need  not 
hesitate.  For  those  experimenters  who 
have  built  the  Baby  Heterodyne  II,  I 
will  say  that  the  same  tuner,  variometer 
and  condenser  can  be  used  for  building 
this  circuit,  and  several  of  our  readers 
have  already  done  this  successfully. 
The  aperiodic  coupler  has  been  described 
many  times  in  these  columns,  but  for 
the  benefit  of  the  newcomers,  I  will 
repeat  these  specifications. 

Both  the  primary  (LI)  and  the  sec- 
ondary coil  (L2)  are  wound  on  the  same 
cardboard  or  bakelite  tube.  This  tube 
is  about  three  inches  in  diameter  and 
four  inches  long.  Coil  (LI)  consists  of 
15  turns  of  No.  26  double  silk  covered 
wire,  wound  1-2  inch  from  one  end  of  the 
tube.  The  secondary  coil  (L2)  contains 
about  60  turns  of  the  same  size  wire 
and  is  started  about  1-2  inch  from  the 
end  of  coil  (L2).  In  other  words,  there 
is  1-2  inch  space  between  (LI)  and  (L2). 
Lnder  certain  conditions,  particularly 
with  long  aerials,  it  may  be  necessary  to 
reduce  slightly  the  number  of  turns  on 
(L2),  say  by  five  to  eight  turns,  in  order 
to  bring  in  stations  on  short  wavelengths 
around  the  200-meter  mark.  This  is 
best  determined  experimentally  at  the 
time  the  set  is  built,  owing  to  the  great 
variation  in  the  constants  of  commercial 
condensers  and  variometers. 

To  avoid  long  wires,  it  is  generally 
best  to  support  the  coil  on  the  back  of 
the  condenser  by  means  of  short  brass 
brackets  which  also  serve  as  the  con- 
nections (4-7)  between  the  coil  (L2)  and 
condenser  (CI).  The  jumper  wire  con- 
nection (3)  may  or  may  not  be  necessary, 
depending  upon  local  conditions,  but  as 


a  rule  this  is  desirable,  as  it  greatly 
reduces  body  capacity.  The  extreme 
outer  turn  (c)  of  coil  (L2),  the  end  far- 
thest away  from  the  primary  (LI)  should 
be  connected  to  the  grid  line  (4-5),  and 
it  should  be  particularly  noted  that  the 
"stator"  or  stationary  plates  of  (CI) 
should  be  connected  to  (c),  and  also 
(4-5).  If  this  is  not  done,  then  there  is 
likely  to  be  trouble  with  body  capacity. 

Any  standard  variometer  will  work 
well  in  this  circuit,  but  if  possible,  obtain 
a  "plate  variometer"  especially  designed 
to  work  in  the  plate  circuit.  This  vario- 
meter has  fewer  turns  of  heavier  wire 
than  the  "grid"  type  variometer.  How- 
ever, both  will  give  results  if  it  is  impossi- 
ble to  obtain  these  distinctive  windings. 
It  wiil  be  well  to  keep  the  variometer 
well  away  from  the  tuning  coil  (L1-L2) 
so  that  there  will  be  no  coupling  between 
the  two  units,  and  for  the  best  results 
it  is  better  to  incline  the  coupler  at  a 
considerable  angle  so  that  the  axis  of  the 
coupler  does  not  coincide  with  the  axis 
of  the  variometer  stator. 

Condenser  (CI)  should  be  of  the  ver- 
nier type,  capacity  0.0005  m.  f.  (23 
plates).  This  form  of  coupler  is  very 
sharp  and  a  vernier  arrangement  of  some 
kind  is  therefore  highly  desirable.  For 
the  tubes  ordinarily  used,  the  grid  con- 
denser (CG)  should  be  of  the  mica  type 
with  a  capacity  of  0.00025  mf.  While  a 
variable  grid  leak  is  the  best,  a  1.0 
megohm  fixed  leak  will  generally  be  very 
satisfactory.  The  bypass  condenser 
(Kl)  has  a  capacity  of  0.002  mf.  and  is 
effective  in  reducing  the  impedance  of 
the  plate  circuit,  for  the  phones  (PH) 
and  the  "B"  battery  both  introduce  a 
high  resistance  to  the  radio  frequency 
currents  in  this  circuit.  The  "B"  battery 
voltage  may  range  from  16  to  45  volts, 
but  with  the  average  tube  it  is  likely  that 
22.5  volts  will  be  perfectly  satisfactory. 

Picking  the  Tubes 

\  NY  type  of  standard  tube  will  give 
-^*-  satisfactory  results,  ranging  from 
the  WD-12  to  the  UV-201A  or  the  UV- 
200.  The  latter  is  somewhat  more  sen- 
sitive as  a  detector  and  will  give  good 
results  on  voltages  not  much  exceeding 
22.5  volts.  This  tube  is  sharper  and 
more  critical  than  the  hard  tubes.  The 
battery  "A"  depends  upon  the  tube 
used.  For  the  WD-12,  a  single  1.5  volt 
cell  of  dry  battery  is  used.  For  the  UV- 
199  we  use  three  dry  cells  in  series,  giving 
a  total  of  4.5  volts,  while  for  the  UV-200 
and  UV-201-A  a  six  volt  storage  battery 
is  best. 

It  is  best  to  leave  the  aerial  and  ground 
wires  (1)  and  (2)  connected  temporarily 
until  the  set  is  completed  and  can  be 
tuned  in.  Now  connect  the  aerial  (AN) 
and  the  ground  connection  (GND)  to 
(a)  and  (b)  alternately,  until  the  best 
results  are  obtained.  When  this  is  deter- 
mined, the  connection  of  the  primary 
(LI)  can  be  soldered  in  permanently. 
There  is  one  connection  that  is  best 
and  experiments  alone  can  determine 
this. 

As  with  all  regenerative  circuits,  this 
circuit  will  re-radiate  from  the  aerial  if 
not  carefully  handled,  but  owing  to  the 
small   ratio   between   the   turns   on   coils 


The  Magazine  of  the  Hour 

(Ll)  and  (L2)  this  effect  is  not  as  bad  as 
with  the  majority  of  circuits  of  this 
nature.  It  is  nowhere  near  as  bad  as  a 
single  circuit  tuner  and  is  better  than 
the  majority  of  vario-coupler  types 
having  a  greater  number  of  turns  on  the 
primary.  The  looser  the  coupling  be- 
tween (Ll)  and  (L2)  the  less  trouble 
there  will  be  from  local  "razzing"  and 
interference. 

Do  not  let  your  tube  whistle  or  howl 
in  tuning,  and  when  you  tune  into  a  wave, 
tune  in  sharply.  Don't  get  in  on  the 
fuzzy  edge  of  a  wave.  Don't  keep  your 
tubes  heated  up  to  bright  incandescence. 
If  you  obey  these  instructions,  you  will 
not  cause  much  disturbance  in  the  neigh- 
borhood. 

From  those  of  our  readers  who  have 
tried  out  this  circuit  from  sketches  mailed 
to  them  before  this  article  was  written, 
we  have  had  remarkable  reports  on  its 
selectivity  and  range.  It  is  a  simple, 
stable  circuit  without  any  gew-gaws, 
and  should  appeal  to  the  beginner  in 
radio. 


Making  Everybody  Happy 
from  WEAF 

(  Continued  from  page  28) 

become  familiar  to  millions  of  radio 
listeners  in  all  parts  of  the  country.  It 
has  covered  the  country  quite  thoroughly, 
for  no  less  than  eighteen  stations  were 
linked  together  with  WEAF  when  he 
announced  the  conventions'  proceedings. 
McNamee's  abilities  are  not  limited  to 
handling  political  events.  He  is  a  baritone 
of  no  little  distinction,  having  won  the 
encomium  of  such  renowned  critics  as 
Richard  Aldrich,  W.  J.  Henderson,  Hen- 
ry T.  Fink  and  others.  In  spite  of  the 
demands  of  WEAF's  microphone,  Mc- 
Namee  still  appears  as  soloist  in  some  of 
New  York's  famous  churches. 

Expanding  Old  New  York 
/^iLD  Broadway  and  Fifth  Avenue  have 
^— '  been  much  spoiled  by  celebrities,  for 
Father  Knickerbocker  breeds  'em  big. 
Before  the  advent  of  radio,  New  York 
had  sole  claim  to  these  favorite  sons  and 
daughters,  and  Main  Street  and  the 
rolling  prairies  and  mountains  beyond 
caught  a  glimpse  of  their  greatness  only 
through  the  Sunday  newspapers  or  when 
they  made  a  rare  tour  into  the  wilderness 
of  the  Great  West. 

However,  to  WEAF  is  due  the  credit 
of  pioneering  in  the  field  of  radio  and 
giving,  in  tones  of  sound,  the  privileges 
of  becoming  acquainted  with  the  great. 
Thus,  the  Bowery  of  New  York  and  the 
stockyards  of  Chicago  were  put  on  an 
equal  plane.  The  greatest  individuals 
of  all  time,  including  stars  of  the  stage 
and  lights  of  the  political  world,  have 
been  in  the  studio  of  WEAF 

The  privilege  of  announcing  these 
celebrities  has  fallen  in  a  large  degree  to 
A.  V.  Llufrio,  accompanist  and  an- 
nouncer. As  announcer  his  voice  has 
become  familiar  to  millions,  and  as 
accompanist  he  has  broken  records,  for 
he  has  accompanied  more  entertainers 
than  any  other  individual  in  the  country. 

Copyright.  1925.  by  Radio  Age  Inc. 


48 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


The  "99"  Reflex  Receiver 
with  Two  Stages 

(  Continued  from  page  41) 

23  plate  (0.0005  mf)  size.  It  is  far  the 
best  to  buy  the  transformers  (RFT-1) 
and  (RFT-2)  as  the  home  made  coils  are 
seldom  entirely  satisfactory,  and  in  the 
end  they  often  prove  even  more  expensive 
than  the  home  wound  units. 

For  those  who  are  determined  to  wind 
their  own  coils,  however,  I  will  say  that 
they  are  wound  on  two  tubes,  an  outer 
tube  3 "  diameter  and  an  inner  tube 
2.5"  diameter,  either  of  cardboard  or 
bakelite.  The  secondary  coil  consists  of 
60  turns  of  No.  26  D.  S.  C.  wound  over 
the  outer  tube  while  the  primary  con- 
tains 12  turns  of  the  same  size  wire  wound 
at  one  end  of  the  inner  tube.  The 
primary  coil  is  so  located  that  it  lies  just 
beyond  the  end  of  the  secondary  and  so 
that  there  can  be  no  capacity  coupling 
between  the  two.  For  convenience,  the 
transformers  are  attached  to  the  backs 
of  the  variable  condensers  by  brass 
brackets  and  are  tilted  up  so  that  they 
are  not  magnetically  coupled,  say  at  an 
angle  of  about  60  degrees  with  the  hori- 
zontal. Please  note  that  the  outer  turn 
of  the  secondary  coil  on  the  end  farthest 
from  the  primary  goes  to  the  grid  of  the 
tubes.  Also  note  that  the  rotor  (movable 
part  of  the  condensers)  go  to  the  ( — A) 
line  while  the  stators  (stationary  blades) 
are  connected  to  the  grid  (G)  circuits. 
At  (L3)  we  have  the  tuned  plate  induc- 
tance which  consists  of  a  50  turn  honey- 
comb or  50  turn  stagger  wound  coil,  this 
being  tuned  by  the  0.00035  mf  vernier 
condenser  (C3)  which  is  of  the  same 
capacity  as  the  other  variable  condensers. 
This  comprises  the  tuning  controls. 
All  of  the  amplifying  tubes  (T1-T2-T3) 
are  either  of  the  199  or  201A  type  operat- 
ing on  a  "B"  battery  voltage  of  67.5  to 
90  volts.  The  two  element  detector 
tube  (DT)  is  shown  in  place  of  the  crystal 
detector  as  it  is  more  difficult  to  show  this 
than  the  crystal. 

The  negative  ( — D)  is  connected  to  one 
side  of  the  circuit  while  the  plate  is  con- 
nected at  (PP).  The  positive  (  +  D) 
goes  straight  to  the  detector  battery 
(DB)  without  further  connection  to  the 
circuit  or  rheostat. 

As  the  diode  tubes  are  1.5  volt  tubes, 
it  is  best  to  use  a  single  separate  dry 
cell  for  this  tube  as  shown  at  (DB).  As 
this  tube  is  not  critical  no  rheostat  need 
ordinarily  be  used  although  it  is  some- 
times desirable  to  cut  down  the  flow  of 
current  with  a  fresh  battery.  When  a 
crystal  detector  is  used,  connect  it  be- 
tween (  +  D)  and( — D),  of  course  omitting 
the  battery  (DB).  Either  one  or  the 
other  detector  may  be  used  with  perfect 
success. 

The  Audio  Circuits 
TpUBE  (T3)  is  the  audio  amplifying 
-*-  tube  connected  to  the  first  part  of 
the  circuit  by  the  audio  transformers 
(AT — 2).  This  forms  a  simple  single 
stage  of  audio  amplification,  and  to  insure 
maximum  volume,  clarity,  and  mini- 
mum "B"  battery  current  a  4.5  volt 
"C"  battery  marked  (C2)  is  used.  The 
( — )  pole  of  the  battery  goes  to  the  grid 
post  (G)  of  the  tube  socket.  The  first  audio 


frequency  transformer  (AT — 1)  is  the  reflex 
transformer  used  in  the  single  tube  "99" 
circuit  and  is  connected  in  just  as  before. 
It  will  be  well  to  examine  the  four 
markings  shown  at  the  ends  of  the  pri- 
mary and  secondary  coils  of  these  audio 
transformers  so  that  no  mistake  will  be 
made  in  connecting  them  up.  The  "C" 
battery  (CI)  is  also  a  4.5  volt  battery 
used  for  biasing  the  radio  frequency 
stages.  A  potentiometer  (PO)  of  200 
ohms  is  connected  like  a  rheostat  in  the 
grid   return   to   suppress   oscillations. 

As  all  of  the  bypass  fixed  condensers 
(Kl,  K2,  K3,  etc.)  are  marked  with  their 
capacity  on  the  blueprints,  it  seems 
hardly  necessary  to  describe  them  fur- 
ther, except  to  state  that  they  should  all 
be  of  the  mica  dielectric  type.  Various 
makes  of  transformers  have  different 
inductive  values,  but  in  general  these 
fixed  bypass  condensers  will  work  well 
with  almost  any  type  or  make  of  audio 
transformer.  The  ratio  of  the  audio 
transformers  is  not  critical  but  two  5/1 
ratio  transformers  are  probably  the 
best.  At  least  do  not  use  a  ratio  higher 
than  6/1  for  transformer  (AT — 1).  A 
higher  ratio  can  be  used  at  (AT — 2) 
with  some  increase  in  distortion. 

So  sharp  is  the  tuning  of  this  circuit 
that  some  practice  will  be  required  before 
distant  stations  can  be  brought  in.  If 
the  dials  are  not  moved  very  slowly, 
point  by  point,  you  will  surely  skip  over 
a  "hot  spot."  Dial  whirling  will  bring 
you  nothing  and  in  this  respect  the  tun- 
ing greatly  resembles  that  of  a  neutro- 
dyne.  First,  set  all  of  the  variable  con- 
denser dials  at  (O),  where  the  plates  are 
fully  out  of  engagement,  and  then  move 
(CI)  by  one  dial  division.  Next  move 
(C2)  by  one  division  and  then  (C3).  Now 
start  at  (CI)  again  and  move  this  one 
more  division,  following  by  corresponding 
movements  of  (C2)  and  (C3).  Keep 
this  up  until  you  strike  a  wave.  After  the 
stations  are  found  they  should  be  logged 
in  a  memorandum  book  with  their  wave- 
length and  the  dial  settings  that  brought 
them  in.  With  such  a  record  it  is  then  a 
simple  matter  to  find  any  station  in  the 
list  at   any  time. 

Crystal  detectors  should  be  carefully 
inspected  and  tested  before  installing 
them  to  be  assured  of  their  sensitivity. 
Carefully  observe  the  polarity  of  the 
various  connections.  Polarity  is  of  the 
greatest  importance. 

Do  not  use  WD-12  tubes  for  they  are 
poor  R.  F.  amplifiers.  Keep  the  "B" 
battery  voltage  above  45  volts.  The 
ordinary  22.5  volts  used  with  regenera- 
tive outfits  will  not  work. 

Tubes  (Tl)  and  (T2)  both  being  radio 
frequency  amplifiers  can  be  controlled 
by  the  single  rheostat  (Rl)  as  shown. 
In  tnis  respect  it  should  be  noted  that  this 
rheostat  should  only  have  half  the  resis- 
tance required  for  a  single  tube  of  the 
same  type.  Thus,  if  199  tubes  are  used, 
which  require  a  40  ohm  rheostat  for  a 
single  tube,  the  resistance  for  two  tubes 
should  be  15  to  20  ohms.  Two  201A's 
can  be  handled  on  a  7.5  ohm  rheostat. 
The  single  rheostat  (R2)  controls  only 
the  audio  stage  tube  (T3),  hence  this 
should  be  of  nigher  resistance  than  (R2). 
Probably  40  ohms  for  a  199  and  15  ohms 
for   a   201A   would   be   proper   for    (R2). 


Midget  Reflex  Notes 

\  GREAT  number  of  letters  have 
-^*-  been  received  by  RADIO  AGE  from 
those  who  have  built  or  attempted  to 
build  the  Midget  Reflex  published  in 
the  blueprint  section  of  the  November 
issue.  For  the  benefit  of  those  who  have 
experienced  difficulties  I  will  give  a 
little  additional  information  which  I 
trust  will  set  them  right.  With  a  little 
care  and  attention  to  minor  details,  the 
Midget  will  perform  very  well,  and  in 
fact  is  now  in  production  by  a  Chicago 
radio  set  manufacturer  as  one  of  the 
leaders  in  his  line.  It  has  been  thor- 
oughly tested  out  in  every  particular, 
and  for  so  simple  a  rig  it  has  given  very 
good  all  around  results. 

Like  all  reflex  circuits,  the  perform- 
ance of  the  Midget  is  largely  dependent 
upon  the  characteristics  of  the  audio 
transformer  and  particularly  on  the 
impedance  values  of  the  windings. 
(See  Figs.  1-2  of  October  issue.)  The 
variations  among  the  different  makes 
of  transformers  call  for  different  values 
of  the  bypass  condenser  (K2),  and  in 
some  cases  the  distributed  capacity  of 
the  primary  winding  is  so  great  that  the 
condenser  must  be  completely  removed 
from  its  present  position  across  the 
primary  winding  and  then  connected 
across  the  phones  and  "B"  battery. 
The  adjustment  must  be  made  for  each 
different  make  and  ratio  of  audio  trans- 
former. This  adjustment  does  not  apply 
only  to  the  Midget  transformer — it 
applies  to  all  reflex  sets.  Again,  some 
good  makes  of  audio  transformers  give 
excellent  results  on  straight  audio  ampli- 
fication but  are  entirely  unsuited  for 
reflexing. 

Out  of  a  number  of  local  Midget  sets 
which  I  have  serviced  directly,  I  have 
found  many  errors  in  the  connections; 
in  fact  this  seems  to  be  the  major  trouble. 
There  is  a  decided  tendency  toward 
short  circuiting  the  transformer  primary 
by  making  connections  to  the  wrong  side 
of  the  fixed  condenser  (K2),  the  current 
in  this  case  going  straight  through  the 
crystal  to  the  ground  without  affecting 
the  audio  transformer  at  all.  This  mis- 
take occurred  in  five  cases  examined ; 
hence  I  am  of  the  opinion  that  it  has 
happened  in  many  sets  that  I  have  not 
been  able  to  inspect.  In  shooting  trouble 
for  the  local  fans  I  have  found  five 
instances  where  the  crystal  detector 
(CD)  was  connected  to  post  (PI)  instead 
of  to  post  (Bl)  as  it  should  have  been, 
and  with  this  error  the  transformer  is  of 
course  perfectly  useless.  If  your  set 
functions  best  when  the  catwhisker  is 
removed  from  the  crystal,  this  may  be 
one  of  the  reasons.  One  side  of  the 
crystal  detector  must  be  connected  to 
post  (Bl)  and  not  to  post  (PI).  Look 
at  your  set  and  see  that  this  connection 
is  made  properly. 

Two  cases  of  error  were  corrected  for 
readers  who  misunderstood  the  purpose 
of  showing  a  part  of  the  circuit  in  dotted 
lines  (Fig.  2),  they  assuming  that  the 
dotted  lines  indicated  that  these  wires 
could  be  used  or  omitted  at  pleasure. 
All  lines  whether  solid  or  dotted  must 
be  used  in  the  circuit.  I  showed  certain 
(Turn  to  page  60) 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


49 


ctttcC 

Hoolc^TULp^S 

<~^t>tf  ottr  leaders 

'pHE  material  appearing  under  the  title  'Pickups  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  is 
■*•  contributed  by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  circuits 
and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points,  and 
it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


WE  have  noticed  in  the  past  few 
weeks  a  growing  number  of  letters 
requesting  information  as  to  how 
one  may  become  a  Dial  Twister,  and 
what  the  requirements  are  in  submitting 
contributions  to  the  Pickups  and  Hook- 
ups pages.  So  insofar  as  this  is  the 
January  number,  and  the  proper  time  to 
make  resolutions,  we  are  going  to  set 
down  a  few  rules  for  those  uninitiated, 
with  regard  to  membership  and  contribu- 
tions to  these  pages. 

First  of  all,  anyone  can  be  a  member — 
makes  no  difference  if  you're  twelve  or 
forty,  you  are  just  as  welcome  to  write 
in.  When  you  write  to  this  department, 
please  make  your  communications  as  neat 
as  possible  (they  really  stand  a  much 
ibetter  chance  of  being  published),  write 
,them  in  ink  or  on  the  typewriter,  and  do 
'it  neatly  on  a  piece  of  honest-to-goodness 
.correspondence  paper.  In  the  past  year 
-we've  had  contributions  that  were  written 
.on  the  back  of  shoe  boxes,  billheads, 
.calling  cards  and  what  not — with  the 
result  that  they  went  into  the  bloody 
rettysnitch  under  our  desk  because  they 
were  not  even  worthy  of  consideration 
ibecause  they  were  not  neat.  Reading  the 
mail  of  the  Pickups  Section  is  no  little 
job,  and  if  it  is  made  harder  by  poor 
.contributions,  it  is  easy  to  see  that  your 
contribution  won't  stand  half  a  chance 
against  another  that  is  more  neatly  pre- 
pared.    So  much  for  that. 

Now  then  what  you  write  about. 
Whatever  you  do,  make  your  subject  an 
interesting  one.  A  good  humorous  letter 
telling  of  a  funny  radio  incident  is  always 
welcome,  and  quite  a  rarity.  We  are 
always  partial  to  a  good  description  of  a 
circuit  that  has  been  giving  especially 
good  results.  In  describing  circuits,  make 
the  description  short,  interesting  and. 
meaty — don't  waste  a  single  sentence. 
Diagrams  and  specifications  should  ac- 
company. If  they  are  neatly  drawn  in 
black  ink,  we'll  publish  them  as  you 
draw  them. — if  not,  we  redraw  them  as 
best  we  see  fit. 

Good  lists  of  stations  heard  are  of 
course  always  welcome.  We  experience 
no  little  satisfaction  when  one  of  our 
number  has  done  a  creditable  piece  of 
DX  (the  set  you  use  does  not  count). 
What  we  seek  to  compare  is  results — and 
we  doubt  if  you  can  find  a  better  place 
than  the  Pickups  Section  to  do  it.  Sta- 
tion lists  should  be  typewritten  if  possible, 
or  else  neatly  and  carefully  printed. 
Hereafter,  do  not  list  stations  under  five 
hundred  miles  distant.  Of  course  if  you 
use  a  crystal  set,  and  hear  300  or  400 
jriiles,  by  all  means  tell  us  about  it — but 


A.  E.  FRELAN 
Sharon  Hill.  Pa. 


CONTRIBUTORS 

H.  F.  GRAEBKE 
Chicago,  111. 

DIAL  TWISTERS 


J.  B.  RATHBUN 
Blueprint  Editor 


Name  Address  City 

Richard  Baldwin .  .  122  East  Rich  St Columbus.  Ohio 

Edgar  A.  Bare 1S19  N.  3rd  6t Harrisburg,  Pa. 

Harold  R.  Bigelow 118  East  26th  St Chicago.  111. 

H.  T.  Lovett 49  ^Wellington  St Halifax.  N.  S.,  Can. 

Jas.  S.  Geyser 1005  Swiss  vale  Ave Wilkinsburg,  Pa. 

Roger  J.  Kiekeuapp 532  W.  Second  St. Faribault.  Minn. 

Joseph  A.  Sumner 18  Morton  Ct New  Bedford.  Mass. 

C.  N.  Olson Saunders Alberta.  Cau. 

R.  H.  Wakelee 870  E.  146  St Cleveland,  Ohio 

Charles  W.  Switzer Box  646..  . Gananoque,  Ont.,  Can. 

John  Tomlin,  Jr 303  Madison  Ave Atlantic  City.  N.  J. 

Ray  Elzey 2582  Sullivant  Ave Columbus.  Ohio 

George  S.  Richardson 145  S.  Julien  St London,  Ont.,  Can. 

Banton  Cantozinn 1419  Sherman  Ave : Evanston,  111. 

Warren  F.  Bowles SOS  Buckingham  I'l Chicago.  111. 

E.  J.  Skepper %  Florsheim  Shoo  Co..  Adam..  Clinton  <(. :  Je.  e-son  Sts.  .Chicago,  111. 

William  Rowe 35"K  Florence  Ave Highland  Park.  Mich. 

J.  T.  Marshall 286  Indiana  Ave Providence,  R.  I. 

R.  B.  Jack 227  Bank  St Ottawa.  Ont..  Can. 

Paul  M.  Hannium 1424  Wesley  Ave Columbus,  Ohio 

.     R.  Rutten 420  N.  Broadway Leavenworth,  Kans. 

Felix  Fredrickson R.  2 Delmar,  la. 

Frank  McDonald 530  Gaines  St Davenport.  la. 

E.  A.  Irelan Sharon  Hill,  Pa. 

O.  S.  Wallace 205  Lewis  Bldg Montreal,  Que.,  Can. 

Henry  C.  Reeee Apt.  17,  1419  Clifton  N.  W Washington,  D.  C. 

R.  R.  Carpenter R.  D.  2 Wheeling.  W.  Va. 

Wm.  Richardson 31  Ann  St Pittston.  Pa. 

Gilbert  A.  Slater 88  Linwood  Ave Pawtucket,  R.  I. 

R.  H.  Craig 221  Brown  St SaultSte.  Marie,  Out..  Can. 

Oscar  Orneas.  ...       3314  Montrose  Ave Chicago.  111. 

I-eonard  Woloz 6151  Madison  Ave Scran  ton.  Pa. 

J.  Tedola 1342  19th  St Granite  City,  111. 

Clifford  Smith Barons,  Alta.,  Can. 

John  B.  Aikens Grimsby,  E.  Ont.,  Can 

Harold  Jones 7438  Dorchester  Ave Chicago,  111. 

William  Sibley  Law Saxon  Mill Spartanburg,  S.  C. 

James  W.  Dodd 3522  Wabash  Ave..  Evanston Cincinnati,  Ohio 

Joseph  J.  Weuniger 221  Mountain  Ave Pen  Argyle,  Pa. 

Wilbur  Reihard 30  N.  Fulton  St Columbus.  Onio 

Henry  Zimmerman 621  West  St Kenosha,  Wise. 

R.  A.  Roberts Patricia,  Alberta,  Can. 

Lawrence  A.  Brown 4625  Friendship  Ave Pittsburgh,  Pa. 

E.  S.  Parks. 4602  N.  Western  Ave Chicago,  111. 

Myron  D.  Keefe 30  Deaxing  St Jamestown,  N.  Y. 

W.  A,  Northington Box  206 Pratt  City,  Ala. 

Ray  Griffith 325  S.  Grand  Ave Lansing,  Mich. 

Wil  Latraverse 166  Davidson Montreal,  P.  Q-.  Can. 

Irvin  Age 514  E.  G  St         Louisville,  Ky. 

H.  J.  Donohue 2909  McCullo.  k  Ave Wheeling,  W.  Va. 

F.  A.  Webb Armdale,  P.  O Halifax,  N.  S-.  Can. 

Henry  F.  Brunken 9663  Burnette  Ave Detroit.  Mich. 

Marvin  Kriter 341  Bedford  St Cumberland.  Md. 

W.  Worwood,  Jr 1  Montcalm  St.,  Bienville - Liese.  P.  Q..  Can. 

A.  J.  Kralorec 411  Somerville  Ave Menominee,  Mich. 

Robert  S.  Hull 136  E.  Queen  St Chambersburg,  Pa. 

Case  S.  Vreeland 67  Union  St Montclair,  N.  J. 

L.  B.  Wilker 616  Walker  St MUwaukee,  Wise, 

J.  P.  Lucier 6  Fulton  St Menthuen,  Mass. 

J.  B.  Leslie Forest  Ave.,  Attleboro Sedona.  Mass. 

Howard  J.  Wells 75  Avenue  St Oshawa,  Ont..  Can. 

Fulford  Little Boi  174 Algonac,  Mich. 

Leland  J.  Foster 535  Upham  St Petaluma.  Calif. 

Charles  J.  Kirk 3441  Island  Ave Toledo.  Ohio 

F.  C.  Butler 1275  Ethel  Ave Lakewood,  Ohio 

Charles  Justice 433  S.  17th  St Columbus.  Ohio 

Edward  Yerker Ochre  and  Clover  Sts - Mt.  Penn.  Reading,  Pa. 

Mauno  Laine 546  40th  St Brooklyn.  N.  Y. 

H.  Madrich 63  Gordon  Ave Verdun.  P.  Q..  Can. 

Alien  Hannon Freemansburg.  Pa. 

Leslie  Craig 1721  Coy  Ave Saskatoon.  Sask.,  Can. 

F.  B.  Holt 17550  Riopele  St Detroit,  Mich. 

Howard  F.  Grabke 414S  N.  -Ashland  Ave Chicago.  HI. 

Preston  Parson 442  Lindenwood  Ave Akron.  Ohio 

G.  W.  Martin 27  Archer  Ave Buffalo,  N.  Y. 

Levier  Kunkle.. 744  S.  Webb  Ave Alliance,  Ohio 

Richard  T.  McCarthy 615  Graijd  Ave Ames,  la. 

Jo.^e  ph  Rettig 815  Linden  Ave Logansport,  Ind. 

George  R.  Milges 6200  Dorchester  Ave a Chicago,  III. 

Earl  S.  Dietsch 19  Verdun  Ave Buffalo.  N.  Y. 

A.  J.  Berger 3927  Greenmount  Ave Baltimore,  Md. 

William  M.  Hiesler Hawthorne Reading.  Pa. 

F.  T.  Tiener 3673  Lafayette  Ave St.  Louis.  Mo. 

Kenneth  Perry 410  Summit  Ave South  Orange,  N.  J. 

J.  W.  Metzger 1247  K  St.,  S.  E Washington,  D.  C. 

H.  G.  Brown 1106  North  St Peoria,  111. 

James  Kennedy 45  Alpine  St.,  Rox Boston,  Masa. 

Chester  Dominy Route  1 Serena,  111. 

E.  R.  Hopkins 79  Sherwood  Ave Toronto,  Ont.,  Can. 

Irving  Bradford Box  10,  R.F.D.  1 Newport,  N.  J. 

Harry  G.  Owen 3201  Argyle  St Chicago,  111. 

T.  J.  Kent %  P.  M.  R,  R.  Co..  13th  and  Timber  Sts Chicago,  111. 

H.  E.  Wright 143  E.  North  Ave Baltimore,  Md. 

H.  E.  Potter 1  Hayden  St Binghamton,  N.  Y. 

Maurice  Barrat R.R.  10 Logansport,  Ind. 

Bille  Broeker 509  Lecta  Ave Fort  Smith.  Ark. 

Robert  L.  White 4663  Maplewood  Ave Los  Angeles.  Calif. 

S.  Stansfield 8035  Wilson  Ave Detroit,  Mich. 

Thoa.  L.  Kent E.X.  6  U.S..  721  North  Ave Waukegan,  111. 

Nolan  F.  Holt 390  E.  36th  St Portland.  Ore. 


so 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


tube  sets  are  not  working  right  if  they 
don't  do  at  least  500  mile  work  with  the 
present  sending  powers  used — if  you  can't 
do  any  better,  theTechnical  Information 
service  is  the  proper  place  for  you  to 
write.  And  remember  in  listing  stations, 
it's  quality  that  counts — not  especially 
quantity. 

There  has  been  a  terrible  lack  of  good 
photographs  for  these  pages — and  we  are 
herewith  dropping  the  hint  that  they  are 
always  viewed  with  special  favor.  Let's 
have  a  few.  Gloss  prints  are  necessary- — 
any  photographer  will  make  them,  and 
good  clear  photos  are  almost  a  necessity. 
Of  course  we  can  retouch  them,  but  if 
you  save  us  the  trouble  in  the  first  place 
so  much  the  more  chance  of  your  con- 
tribution being  available. 

Now  then,  if  your  contribution  is 
really  worth  while,  we'll  print  it.  You'll 
have  to  leave  that  up  to  our  judgment, 
since  our  experience  in  this  line  tells  us 
just  what  one  fan  will  like,  and  what 
another  will  rave  about.  However,  if 
your  contrib.  does  not  make  the  "line" 
don't  feel  bad  about  It — it's  appreciated 
just  the  same,  and  your  name  will  be 
listed  for  reference  when  another  fan 
wants  to  be  QSO  (in  communication) 
with  another  fan  who  has  had  something 
to  say  on  a  certain  subject. 

So  as  evidence  of  the  fact  that  a  fellow 
has  done  something  along  the  lines  men- 
tioned that  was  especially  meritorious, 
and  of  constructive  nature  to  the  radio 
game,  we  have  been  giving  out  a  little 
button.  It  signifies  that  the  fellow  wear- 
ing it  is  a  real  radio  man — that  he  knows 
the  game  from  a  human  angle — that  he 
has  experienced  the  taste  in  his  mouth 
like  unto  a  blacksmith's  apron  or  the 
inside  of  a  motorman's  glove  after  listen- 
ing or  experimenting  for  hours,  or  that 
he  has  had  some  experience  with  the  game 
that  was  worth  while  mentioning.  And 
believe  us,  we've  seen  fellows  wearing 
that  little  button  on  their  chests  as  one 
fan  put  it  "With  my  chest  sticking  out 
two  feet,  I  was  so  proud." 

The  only  real  requirement  that  exists, 
is  that  you  have  to  be  a  reader  of  RADIO 
AGE  (not  necessarily  a  subscriber),  so 
now  that  we've  got  that  off  our  hook, 
let's  hear  from  you  all — 

Don't  be  a  Dead  Spot! 

—THE  PICKUPS  EDITOR. 

We've  got  a  peach  of  a  starter  this 
month  for  you.  A  fellow  by  the  name  of 
Mr.  A.  E.  Irelan,  living  at  Sharon  Hill, 
Pa.,  has  turned  out  a  circuit  that  he  has 
found  gives  wonderful  results.  What 
makes  us  to  call  it  wonderful  is  that  he 
encloses  a  notation  that  on  December  19 
(Tuesday);  1923,  he  tuned  on  on  SPE 
Rio  de  Janerio,  Brazil.  The  notation 
further  says  that  while  the  programme 
was  entirely  foreign  to  him  the  call  letters 
were  very  plain,  and  there  was  no  doubt 
about  their  identity. 

Since  that  time,  Mr.  Irelan  has  tuned 
in  two  stations  in  England,  one  in  Brazil, 
and  several  in  Canada,  Cuba,  Hawaii, 
California,  and  Washington.  We  are 
printing  his  circuit  in  Figure  1,  with  the 
hope  that  it  may  be  of  interest  to  some 
of  the  other  fans.  In  his  letter  to  this 
department  he  says: 


IMPORTANT    NOTICE 

Regarding  Technical 
Information   Service 

1FTER  January  1,  1925,  the    Technical 
A      Office  of  RADIO  AGE  will  operate 
_/.  A_  under   the    following   rules: 

(1)  Before  writing,  search  your  files  of 
RADIO  AGE,  and  you  will  without  ques- 
tion find  answers  to  your  inquiries  there. 

(2)  Do  not  ask  us  to  compare  advertised 
products.  Information  of  this  nature  should 
be  obtained  from  the  Buyers'  Service  De- 
partment of  RADIO  AGE. 

(3)  Don't  expect  the  Technical  Office  to 
devote  its  entire  efforts  to  your  questions 
by  asking  a  great  number  of  them — stick 
to  the  subject  you  are  puzzled  about,  and 
don't  put  down  everything  you  think  of. 
Do  not  request  information  that  requires  a 
large  amount  of  work;  give  the  other  fellow 
a  chance. 

(4)  Put  questions  in  the  following  form: 
A — A    standard    business    size    stamped, 

self  addressed  envelope  must  be  enclosed. 

B — Write  with  typewriter  or  ink,  and 
on  one  side  of  the  paper  only.  Number 
questions  so  we  can  refer  you  to  them. 

C — Make  diagrams  on  separate  sheets, 
and  fasten  all  correspondence  together. 
Label  your  diagrams  carefully.  Failure  to 
fasten  your  correspondence  usually  results 
in  losing  some  part  of  your  letter  when  the 
mail  is  sorted.  Put  your  name  and  address 
on  each  sheet. 

D — Write  orders  for  back  numbers,  sub- 
scriptions and  the  ANNUAL  on  separate 
sheets.  You'll  get  an  answer  sooner  if  you 
take  the  time  to  write  your  questions  on 
sheets  separate  from  the  orders. 

E — Keep  a  copy  of  your  letter  and 
diagrams  so  that  we  can  refer  you  to  them. 

F — Address  all  requests  for  information 
to  RADIO  AGE,  Inc.,  Technical  Office,  500 
North  Dearborn  Street,  Chicago,  111. 


RADIO  AGE. 
Gentlemen: 

As  I  am  a  great  reader  of  your  maga- 
zine, and  take  great  interest  in  the  new 
circuits  you  publish  from  time  to  time, 
I  couldn't  but  help  noticing  that  hookup 
of  Mr.  Chapman's  in  the  November  issue. 
I  have  a  criticism  to  make  of  his  circuit 
since  he  failed  to  indicate  the  use  of  .002 
condensers  in  the  grid  circuits  of  the 
audio  tubes.  I  use  only  three  tubes,  and 
have  wonderful  results. 

Last  week  I  had  the  pleasure  to  hear 
KDPT,  KPO,  and  KGO  on  the  loud 
speaker  with  good  volume.  At  present 
I'm  listening  to  KFPM  as  I  am  writing 
to  you. 

I  am  at  present  working  on  the  design 
of  a  new  coil  of  the  low  loss  type,  and  I 
have  hopes  that  it  will  be  still  better  than 
the  first  one. 

I  hope  that  the  enclosed  matter  will  be 
of  some  value  to  readers  of  your  unusual 
magazine,  for  which  I  wish  the  greatest 
success. 

Yours  truly, 

A.  E.  IRELAN, 
Sharon  Hill,  Pa. 

STAND  BY 

Mr.  Irelan's  contrib  is  one  of  the 
reasons  why  we  started  this  Dial  Twister 
business.  We  can't  but  admire  a  fellow 
who  is  generous  enough  to  pass  out 
information  of  the  type  he  does.  Only 
too  many  of  the  fellows  in  this  game  are 
"dead  spots"  when  it  comes  to  helping 
out  the  other  fellow.  We  hope  that  if 
any  of  the  readers  of  the  Pickups  con- 
struct Mr.  Irelan's  set,  they  will  let  him 
hear  from  them.  And  the  funny  part  of 
it  is  that  Mr.  Irelan  isn't  satisfied.     Here 


he  has  to  go  and  wind  another  coil — he 
thinks  he  can  make  it  better.  Judging 
from  his  list  of  stations  heard,  and  the 
results  he  jots  down,  that  is '  entirely 
unnecessary.     Fine  business,  DT. 

STAND  BY 

Mr.  Rathbun/  one  of  the  members  of 
our  technical  staff,  probably  better  known 
as  the  "blueprint  editor"  asks  me  to 
correct  an  omission  for  him  with  regard 
to  his  super  heterodyne  receiver  in  the 
December  number.  Hence  the  following: 
Heterodyne  Oscillator  Coil 

By  some  error  we  omitted  the  detail 
sketch  of  the  oscillator  coil,  Fig.  4,  in  our 
December  blueprint  series  and  for  the 
information  of  many  of  our  readers  who 
have  written  to  us  on  this  subject  we 
attach  the  following  sketch.  As  will  be 
seen  from  the  cut,  this  oscillator  is  very 
small  and  compact  and  requires  no  ad- 
justment after  installation. 

The  windings  are  placed  on  two  tubes 
which  are  held  in  a  concentric  position  by 
means  of  small  machine  screws  and 
washers.  The  outer  tube  carrying  the 
plate  and  grid  coils  is  2.5  inches  in 
diameter  while  the  inner  tube  is  1.5 
inches  diameter  and  carries  the  pickup 
coil  by  which  the  oscillations  are  im- 
pressed upon  the  grid  circuit.  All  coils 
are  wound  with  No.  26  D.  S.  C.  wire. 

At  the  bottom  on  the  outer  tube  is  the 
plate  coil  which  consists  of  28  turns  of 
wire.  This  coil  is  separated  by  1-4  inch , 
from  the  grid  coil  above  it,  the  grid  coil 
containing  35  turns  of  the  same  size  wire. 
Inside  this  tube  is  the  pickup  coil  which 
is  wound  at  a  level  with  the  space  between 
the  outer  coils  or  midway  between  them. 
The  pickup  coil  has  only  four  turns.  For 
those  who  wish  to  avoid  the  trouble  of 
making  this  coil,  it  can  be  purchased 
ready  made  at  many  radio  stores. 

We  are  printing  a  sketch  of  the  coil  in 
question  in  Figure  2,  and  hope  to  clear 
up  some  of  the  difficulty  attached  to  its 
omission  from  the  last  issue  of  RADIO 
AGE. 

[STAND  BY 

And  now  to  get  back  to  the  Windy  City 
again— Mr.  H.  F.  Graebke  of  4148  N. 
Ashland  Ave.,  Chicago,  Illinois,  submits 
the  circuit  shown  in  Figure  3.  His  results 
are  very  unusual  as  his  letter  tells: 
RADIO  AGE: 
Gentlemen: 

First  of  all,  let  me  put  in  a  good  word 
for  your  blueprint  section;  with  instruc- 
tions like  the  ones  you  are  printing,  any 
dumbbell  could  make  a  radio  set  and  not 
go  wrong. 

I  have  tried  the  Baby  Het  (shown  in 
the  September  issue),  and  have  had 
very  good  results.  However,  I  did  'not 
use  the  C  (bias)  battery,  substituting  -a 
grid  leak  and  grid  condenser  in  its  place. 
After  I  made  these  changes,  I  got  excel- 
lent results. 

I  am  submitting  my  list  of  DX  stations 
heard  (through  the  summer  up  to  the 
present  time)  on  a  single  circuit  set  with 
the  addition  of  a  variometer  in  the  plate 
circuit.  I  find  that  a  variometer  con- 
nected in  this  way  makes  tuning  much 
sharper,  and  gives  a  much  better  control 
of  regeneration.  I  advise  this  circuit  be 
used  with  a  rather  short  antenna,  and 
if  my  advice  is  followed,  I  am  sure  - 
listeners  who  build  the  circuit  will  find 
interference  at  a  minimum  as  compared 
to  the  average  single  circuit  set. 

By  using  a  bedspring  as  an  antenna,  I 
have  been  able  to  get  stations  in  the  1000 
mile  range  on  a  loudspeaker  pretty  fair, 
many  of  them  while  local  stations  were 
doing  their  darndest.     Have  heard  KGO 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


51 


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52 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


-  FIGURE  ONE 

This  is  the  hook-up  used  in  the  long  distance  radio  receiver  constructed  by  A.  E.  Irelan,  of  Sharon 
Hill.  It  makes  use  of  a  unique  tuning  coil,  which  consists  of  a  primary,  secondary  and  tickler.  The 
primary  is  "untuned,"  but  its  position  in  relation  with  the  secondary  can  be  varied  by  sliding  it  along 
the  tube  on  which  the  secondary  is  wound.  This  feature,  the  designer  states,  adds  greatly  to  the  selectivity 
of  the  receiver.  Attention  is  drawn  to  the  unusual  arrangement  of  the  parts  in  the  two  stages  of  ampli- 
fication. Fixed  condensers  are  used  in  the  grid  circuits  of  each  of  the  amplifying  tubes,  while  the  primary 
and  secondary  coils  of  the  transformers  are  connected  in  parallel.  The  use  of  high  resistance  leaks  on 
each  tube  also  should  be  of  interest. 


Oakland,  California,  on  horn  4  times  out 
of  6  during  the  month  of  September. 
(Editor's  Note:  Mr.  Graebke  sent  in  a 
list  of  DX  stations  heard  which  certainly 
entitles  him  to  a  DT  pin,  but  due  to  the 
length  of  the  list  we  are  not  printing  it. 
Excuse,   please.) 

Maybe  my  list  isn't  as  long  as  a  lot  of 
others  you  have  printed,  but  local  inter- 
ference in  Chicago  is  one  thing,  and  re- 
ceiving DX  through  it  is  another.  And 
considering  that  most  of  these  stations 
were  heard  while  locals  were  going,  I 
don't  think  it's  half  bad. 

Very  truly  yours, 
HOWARD  F.  GRAEBKE. 
4148  N.  Ashland  Ave., 
Chicago,  Illinois. 

STAND  BT 

Inasmuch  as  we  are  well  acquainted 
(probably  only  too  well)  with  Chicago 
interference  we  are  in  a  position  to  admire 
Mr.  Graebke's  heavy  hitting.  We'll  bet 
he's  got  his  arm  in  a  sling  from  twisting 
dials. 

STAND  BY 

With  this  issue  we  are  going  to  start 
a  little  "Strays"  department.  If  the 
fellows  like  it  we  will  keep  it  up  each 
month.  What  we  want  to  try  to  do  is 
give  every  fellow  who  at  least  deserves 
acknowledgment  a  little  comment  pub- 
licly:    SO 

STAND  BY 

STRAYS 

Mr.  Henry  E.  Wendleborn  of  521  S. 
Gunnison    St.,    Burlington,    la.,    submits 

FIGURE  TWO 


a  very  interesting  list  of  stations  heard. 
It's  so  long  and  has  so  many  stations 
listed  on  it  that  we'll  bet  he's  got  radio 
rash  on  the  ears,  calloused  fingers,  and  a 
stare  on  him  (from  lack  of  sleep)  like  a 
china  doll.  He  knows  a  lot  about  single 
circuits.  Some  of  you  fellows  drop  him 
a  line. 

STAND  BY 

Mr.  W.  J.  Potter,  15  Auriol  Rd.,  W  14, 
London,  England,  sends  in  an  interesting 
contribution  with  regard  to  a  comparison 
of  our  and  English  broadcasting  systems. 
We  regret  we  don't  have  space  enough  to 
print  it — but  hope  that  we  may  find  an 
opening  for  it  later.  Thank  you,  Mr. 
Potter.     It  was  very  interesting. 

STAND  BY 

John  T.  Marshall,  Jr.  of  286  Indiana 
Ave.,  Providence,  R.  I.,  submits  a  circuit 
(very  much  like  the  One  Control  Go- 
Getter)  which  he  says  he  will  be  glad  to 
give  to  anyone  writing  him.  We  are 
sorry  we  can't  print  it — but  would  advise 
any  of  the  bugs  looking  for  improvements 
on  the  Go-Getter  to  write  him.  Come 
again,  Johnny. 

STAND  BY 

Gilbert  A.  Slater  of  88  Lin  wood  Ave., 
Pawtucket,  R.  I.,  says  he  did  some  inter- 
esting work  with  the  1  Tube  Reflex  and 
1  Tube  Loop  circuits  printed  in  recent 
blueprints  in  the  RADIO  AGE,  and  is 
willing  to  pass  the  dope  on  if  you'll  write 
him.     Wot  say? 

STAND  BY 

Felix  Fredrickson  or  Route  2,  Delmar, 
la.,  has  a  circuit  for  those  long  wave 
British  stations,  and  says  he'll  hand  it 
out  for  the  writing. 

STAND  BY 

George  S.  Richardson  of  145  St.  Julien 
St.,  London,  Ontario,  Can.,  and  C.  N. 
Olson  of  Saunders,  Alta.,  Canada,  are 
two  Canadian  bugs  who  sent  in  lists  that 
would  make  you  green  with  envy. 

STAND  BY 

John  Tomlin  of  303  Madison  Ave., 
Atlantic  City,  N.  J.,  a  sixteen  year  old 
boy,  sends  in  a  list  of  stations  which  is 
certainly  one  of  the  best  we  have  as  yet 
ever  seen.  On  November  28th,  1924,  he 
tuned  in  fifty  three  stations  in  one 
stretch  at  the  set.  The  list  he  submits 
comprises  receptions  all  the  way  from 
KFI  at  California  to  6FL,  Sheffield, 
England,  and  then  back  to  California 
with  KHJ.  In  addition,  he  has  heard 
(at  other  times)  eleven  stations  on  the 
Pacific  coast,  6FL  England,  2BD  Scot- 
land, PTT  Madird,  Spain,  VOX  HAUS, 
Berlin,  Germany,  and  Lyons,  France. 
He  uses  a  manufactured  set. 


STAND  BY 

Warren  F.  Bowles  of  808  Bucking- 
ham Place,  Chi — KAgo,  Banton  Can- 
tozian  of  1419  Sherman  Ave.,  Evanston, 
111.,  Ray  Elzey  2582  Sullivant  Ave., 
Columbus,  Ohio,  and  Henry  C.  Reece  of 
Apt.  17,  1419  Clifton  N.  W,  Washington, 
D.  C.  all  send  in  exceptionally  long  DX 
lists.  Our  printer  gets  the  heeby-jeebys 
when  we  give  him  long  lists  like  that  to 
set  up,  so  we'll  let  him  off  easy  this  time. 

STAND  BY 

Mr.  R.  H.  Craig  of  221  Brown  Street, 
Sault  Ste.  Marie,  Ont.,  Canada,  wants  us 
to  tell  him  what  we  think  about  his  list 
of  102  stations  heard  in  19  days.  The 
verdict  is  that  we're  only  too  glad  to  make 
you  a  DT,  and  what's  more,  not  only 
admire  your  list  of  stations  but  the  care- 
ful way  in  which  you  kept  check  on  your 
listening  time. 

STAND  BY 

If  Julian  Lopez  will  send  in  his  address, 
we'll  send  him  a  button.  His  list  makes 
him  a  Dial  Twister,  and  there's  a  button 
waiting  here  for  him. 

STAND  BY 

Harold  R.  Bigelow  of  118  East  26th 
St.,  Chicago,  111.,  got  an  English  station 
three  times  at  different  times  with  a  three 
tube  neutrodyne  built  after  plans  (of  Mr. 
Rathbun)  in  a  recent  issue  of  RADIO 
AGE. 

STAND  BY 

Joseph  A.  Sumner  of  18  Morton  Ct., 
New  Bedford,  Mass.,  says  the  circuit  of 
the  November  issue  (the  Low  Loss  Re- 
generator) is  a  peach.  He  sends  in  a  list 
of  DX  stations  to  substantiate  his  claim" 

STAND  BY 

Jas  S.  Heyser  of  1005  Swissvale  Ave., 
Wilkinsburg,  Pa.,  George  R.  Milges  of 
6200  Dorchester  Ave.,  Chi— KAgo,  111., 
Billie  Broker,  509  Lecka  Ave.,  Ft.  Smith, 
Ark.,  A.  J.  Kralovec  of,  411  Somerville 
Ave.,  Menominee,  Mich.,  W.  Worwood, 
Jr.,  1  Montcalm  Street,  Bienville,  Levis, 
P.  Q.,  Canada,  and  Robert  S.  Shull,  136 
East  Queen  St.,  Chambersburg,  Pa.,  all 
get  DT  buttons  for  long  lists  sent  in. 

STAND  BY 

Mr.  H.  G.  Brown,  1106  North  St., 
Peoria,  111.,  challenges  all  one  tube 
operators  with  a  list  of  stations  that  in- 
cludes England,  Porto  Rico,  Cuba, 
Canada,  and  38  states,  with  a  topnotcher 
of  58  stations  heard  in  one  night.  Verifi- 
cations on  all  receptions.  Sicc'em,  Mr. 
Brown. 

STAND  BY 

Oscar  Orneas  of  3314  Montrose  Ave., 
Chicago,  111.,  bemoans  a  tube  gone  west, 
and  wants  to  caution  us  against  letting 
the  high  voltage  B  battery  lead  slip 
against  the  A  battery  circuit  wires.  S'tu 
Bad.  We  know  that  four  dollar  feeling 
too. 

STAND  BY 

F.  F.  Feiner,  of  3673  Lafayette   Ave., 

St.  Louis,   Mo.,  says  that  you  can  use  a 

stick  of  Dennison's  Black  Sealing  Wax  to 

fill  holes  in  panels  that  are  battle  scarred. 

(Continued  on  page  54) 


WitnlTlt 


FIGURE  THREE 


fWtrtS  "I 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour  S3 


O?lbdulation  plus  ^generation 


* 


RADIO 
SECTION] 


-  V 


PAG^ 


REGENERATION 


— I Tonh  on  Loud  Speaker 


Modulation    Pi-    -CModTl 
is  the  keynote  of  the  "« 
L-2  Ultradyne  R«Le™ertll;s  *ew 
era,ion    as    app hed   «   Jh 
r*°Vea.«    "ectSion   than 
duces    greater    .  Jetect  on— 

^fr.eplnrt.o'enSneering 
a  vital  step  "'  ;»  „r„,lnces  Ire 
This    combination    P~^   ^ 

mendous  ^-n,,,  Allows  the 
ceiving^weak  signals.    AU 

Ultradyne  to   "«£*"  signa,s 

small  amount  «*«2&  ot  Smes 

^orlhefr-aetected     and 

mt.  ^Thomas,  509  Coppm 

^  rarest 

^.t^L^htolAu^-h, 

1Q24    1   tuned    in    on    my 
dyne,  the  following  stations. 
"wBZ       Springfield.  Mass. 
Newark,   N-   ■>• 
Schenectady- ■N-1- 
New  York,  N.  y. 
Washington.  U.^- 
New  York,  N.  X. 
Philadelphia,  ra. 
Pittsburgh,    "a. 
Zion.IU. 
Providence,  R-  »• 
Buffalo.  N.  I. 
-.-,      Elgin,  HI- 
WAAM    Newark,  N.  J- 
WABM    Saginaw,  Mich* 
WIS  AC    Boston,  Mass 

'     Providence.  K.  i» 
Cincinnati.  0. 
St.  Louis.  Mo. 
Detroit.  Mich. 
Des  Moines,  las 
Cleveland  0. 

Troy,  N.  Y- 
Jefferson  City.  Mo. 


WSB 

WMC 

WOC 

WBAP 

WNYC 


w  r  n--» 

WSAI 

KFKX 

WCK 

WBT 

KFK.B 

WGAQ 

KGO 

KF1M 

KH 

WDAF 


WOR 

WGV 

WHN 

WCAP 

WEAF 

WOO 

KDKA 

WCBD 

WJAR 

WGR 

WTAS 


WEAN 

WLW 

KSD 

WW.1 

WHO 

WTAM 

WHAZ 


Atlanta,  Ga. 
Memphis.  Tenn 
Davenport,  la. 
Ft.  Worth,  Tex. 
WPlIi-     New  Jork,  N-  Y, 
-WO^W    Omaha,  Nebr. 
WFAA     Dallas,  Tex 

Cincinnati.  t>. 
Hastings  Nebr. 
St.  Louis,  Mo. 
Charlotte,  N.  C. 
Milford,  Kan- 
Shreveporl,    If. 
Oakland,  Calif. 
Grand  Forks,  N.  D. 
Los  Angeles,  Calif. 
.     Kansas  City,  Mo. 

remarkable  as i  «  ompHshed 

sidering  it  was  ■»  ,     j,    but 

^LTst^nV^^- 
heretofore    expenenced"       uj  ^ 

meters,  and  h. '^  him  on  the 
ful  that  1  can  ree"ve  slage  of 
loud  speaker,  with  one  g^  ^ 
audio,  loud  enough    o  h  ^ 

block   away;   w"™> »  ^hen 

tenna.  g™un<*  °  ,ir  1 can  tunc 
WLW   is  on  the  an-,  ^.^ 

him  out  «mP'e  ,';  WHB  and 
^B   on   42     me    pr  ;  ^H  pwx 

^^.W  on  400  meters,  but 
S    soJeUa,    above    that 

,     jve-  r   .,„   other   receiver 

»I   know   of    no    otner 

volume  and  distance. 


MODEL    L-2 

This  application  of  regeneration 
is  the  most  recent  development 
of  R.  E.  Lacault,  E.  E.,  A.  M.  I. 
R.  E.  since  his  perfection  of  the 
'•Modulation  System"  used  ex- 
clusively in  the  Ultradyne  and 
which  has  so  revolutionized  all 
conception  of  selectivity,  sensi- 
tivity, volume  and  range. 
This  Model  L-2  Ultradyne,  with- 
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of  present  day  super-radio  engi- 
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transformers,  especially  designed  by  R. 
E.  Lacault,  Consulting  Engineer  of  this 
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To  protect  the  public,  Mr.  Lacault's 
personal  monogram  seal  (R.  E.  L.)  is 
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Ultraformers  are  guaranteed  so  long  as 
this  seal  remains  unbroken. 


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*     Tested  and  Approved  by  RADIO  AGE     * 


54 


RADIO  AGE  for  January,   1925 


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Pickups  and 
Hookups 

(Continued  from  page  52.) 
Try  it.     Shave  the  excess  wax  off  with  a 
razor  blade. 

STAND  BY 

One  of  our  California  Twisters  gives  an 
interesting  account  of  some  super- 
heterodyne experiences.  He  also  tells 
us  about  that  "grand  and  glorious  feel- 
ing" upon  getting  his  DT  button: 

Box  363,  National  City,  Calif. 
Dear   Editor: 

You  can  imagine  my  surprise  when  the 
mail  man  handed  me  a  letter  from 
'Radio  Age."  I  was  more  surprised 
when  upon  opening  the  letter  a  Dial 
Twisters  pin  dropped  out.  This  little 
pin  has  caused  much  comment  among 
the  fellows  and  I  thank  you  very  much 
for   it. 

Another  reason  for  writing  this  letter 
is  to  report  upon  the  Super-Heterodyne 
receiver  which  I  became  the  owner  of 
last  spring.  I  find  that  the  best  results 
are  those  obtained  by  the  use  of  a  wire 
twenty  to  thirty  feet  long.  By  the  use 
of  this  small  indoor  aerial,  I  can  tune 
in  stations  that  are  at  right  angles  to  the 
small  internal  loop.  I  have  also  tried 
the  use  of  a  larger  loop  and  of  a  ground, 
separately;  these  increase  the  volume 
above  that  obtained  when  using  the 
small  loop,  but  they  are  not  as  good  as 
the  small  indoor  aerial  for  the  set  has 
to  be  turned  in  tuning  when  they  are 
used. 

Besides  being  inexpensive  in  upkeep, 
this  receiver  is  one  of  the  easiest  sets  to 
tune  as  there  are  only  two  main  controls, 
besides  easy  to  control  the  set  tunes  very 
sharp  as  I  have  received  the  following 
stations  one  after  another  with  absolutely 
no  interference:  KLZ,  Denver,  283  M., 
KFRC,  San  Francisco,  280  M.,  and 
KFSG,  Los  Angeles,  278  M. 

I  will  close  in  saying  that  of  all  of  the 
radio  magazines  on  the  market  today  I 
will  take  RADIO  AGE  every  time. 
Respectfully  yours, 

Lloyd  Stove. 

STAND  BY 

We  think  that  gives  us  some  kind  of  an 
idea  as  to  what  a  super-heterodyne  can 
do  under  adverse  conditions,  and  believe 
us,  a  lot  of  credit  goes  to  Mr.  Stove  for 
breaking  the  ice.  Honestly,  we  thought 
that  owners  of  super-het  were  all  "dead 
spots"  when  it  came  togivinginformation. 

STAND  BY 

We  would  like  to  suggest  the  following 
as  the  official  greeting  song  of  all  Dial 
Twisters,  giving  of  course  all  credit  due 
Harry  Giess  of  WQJ,  Chi — KAgo.  The 
tune  is  quite  familiar  to  all  those  of  you 
who  have  heard  the  Howdedo  song 
Heh   Heh. 

How  Do  you  Do,  Dial  Twister 

How  Do  you  Do? 

How  Do  You  Do,  Dial  Twister 

How  are  you? 

Every  morn'  you're  nearly  dead, 

With  the  receivers  on  your  head, 

Why  don't  you  go  to  bed? 

How  Do  you  Do? 

STAND  BY 

And  thats  all — there  is  no  more.  Wish- 
ing you  a  very  Merry  Radio  New  Year 
we'll  sign  off  until  February  when  you'll 
find  us  back  of  the  blueprint  pages  jus' 
like  ever  before.  Goo  bye! 
End. 
*     Tested  and  Approved  by  RADIO  AGE     * 


The  Magazine  of  the  Hour 

How  to  Make  a  Station 
Finder 

( Continued  from  page  25) 
operating,  but  we  are  at  a  loss  where 
to  set  the  dials.  Bring  the  Station 
Finder  over,  set  it  on  top  of  the  cab- 
inet of  the  set,  and  start  the  buzzer 
going.  Referring  to  our  chart  we  find 
that  500  meters  would  be  at  77  on  the 
Station  Finder  dial,  and  so  we  set  the 
dial  to  that  reading.  Then  we  tune  the 
receiver  to  the  tune  of  the  buzzer,  until 
we  hear  it  loudest.  When  that  has  been 
done,  the  buzzer  may  be  turned  off,  and ' 
the  final  details  of  vernier  touches  can  ' 
be  put  on  the  signal  which  should  be 
there  if  there  is  any  to  be  heard.  And  it 
will  if  your  Station  Finder  is  accurate  and 
you  have  made  your  readings  correctly. 

The  same  goes  for  regenerative  sets — 
tune  the  set  to  the  wavelength  of  the 
Station  Finder  which  is  set  at  the  dial 
reading  corresponding  to  the  wavelength 
shown  by  the  chart,  and  then  turn  your 
regeneration  up  slowly  and  carefully  until 
it  is  just  under  the  spillover  point — and 
not  over  it. 

Other  interesting  experiments  can  be 
performed  with  the  Station  Finder — it 
can  be  used  as  a  tuning  circuit  for  a  crystal 
receiver,  it  may  be  used  as  a  wave  trap, 
it  may  be  used  as  a  filter,  to  balance 
neutrodynes,  as  a  check  on  coils  to  tell 
whether  they  are  wound  large  enough  or 
whether  they  are  too  small.  In  fact  it  is 
probably  one  of  the  most  useful  and 
desirable  things  you  can  have  around  the 
place. 

But  probably  best  of  all,  it  is  almost  a 
sure  fire  preventer  of  regenerative  squeals, 
because  it  teaches  you  how  to  tune  cor- 
rectly and  do  some  real  accurate  and 
practical  radio  experimental  work. 


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I    N. 


RADIO  AGE  for  January,  1925 


What  the  Broadcasters  are  Doing  55 


Write  today  for  your  free  copy  of 

Ward's  New  Radio 
Catalogue 


4 


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for  this  book.  See  for  yourself  the  savings. 

Our  53'Year'Old  Policy 

For  53  years  we  have  sold  quality  merchan- 
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56 


RADIO  AGE  for  January,  1925 


A  constant  factor 

in  radio  development 


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Radio  design  progresses  rapidly  —  but  radio's 
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The  Magazine  of  the  Hour 

The  Modified  Reinartz  with 
Two  Stages 

(Continued  from  page  27) 
"G"  on  the  second  socket  and  the  post 
marked  "F"  on  the  transformer  is  con- 
nected to  the  negative  side  of  the  fila- 
ment battery  circuit.  Binding  post  "P" 
on  the  second  or  first  stage  socket  is  con- 
nected to  the  top  spring  on  the  second 
jack.  The  second  spring  from  the  top  on 
this  jack  is  connected  to  the  post  "P"  on 
the  second  transformer,  and  the  third 
spring  from  the  top  on  this  second  jack 
is  connected  to  the  post  marked  "B  posi- 
tive" on  this  second  transformer,  and  the 
bottom  spring  as  well  as  the  bottom 
spring  on  the  third  jack  is  connected  to 
the  90  volt  positive  plate  battery  binding 
post  on  the  panel. 

Post  "G"  on  this  second  transformer 
is  connected  to  post  "G"  on  the  third 
socket  and  the  post  marked" — F"  on  this 
transformer  is  connected,  like  that  of  the 
first,  to  the  negative  side  of  the  filament 
battery.  The  top  spring  on  the  third 
jack  is  connected  to  the  post  marked  "P" 
on  the  third  socket.  The  filament  circuit 
is  wired  in  the  usual  way,  from  the  nega- 
tive filament  battery  post  on  the  panel, 
to  one  side  of  each  of  the  rheostats,  the 
other  rheostat  terminals  being  connected 
to  the  filament  binding  posts  on  their 
respective  sockets.  The  other  filament 
binding  posts  on  the  sockets,  according 
to  the  directions,  have  already  been  con- 
nected to  the  ground  and  to  the  positive 
binding  post  of  the  filament  battery. 

There  are  several  things  to  which  the 
builder's  attention  should  be  called.  One 
of  these' is  to  make  sure  that  the  gridleak 
and  condenser  are  mounted  as  close  to 
the  "G"  binding  post  on  the  first  socket 
as  possible,  as  this  shortens  the  grid  leak 
and  gives  less  chance  for  interference, 
such  as  howls  and  squeals. 

Some  Final  Cautions 

The  next  thing  to  be  carefully  watched 
is  to  be  absolutely  sure  that  the  binding 
posts  marked  " — F"  on  both  of  the  trans- 
formers are  actually  connected  to  the 
negative  side  of  the  filament  battery. 
If  by  any  chance  they  are  connected  to 
the  positive  side,  then  the  amplifier  will 
refuse  to  work  and  louder  signals  will  be 
obtained  in  the  detector  jack  than  in 
either  of  the  amplifier  jacks.  Care  should 
also  be  used  in  replacing  the  storage  bat- 
tery after  charging  to  make  sure  that  the 
wires  are  not  reversed,  as  this  will  throw 
the  negative  on  the  wrong  side  and  will 
give  the  grids  of  the  amplifier  tubes  the 
wrong   polarity. 


RADIO  AGE  will  be  on  the  air 
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Amplifies  low,  middle  and  high 
tones — all  to  the  same  big  Volume, 
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RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hoi 


57 


Take  Good  Care  of  Your  Head- 
phones 

(Continued  from  page  14) 

2)  The  electromagnets  and  coils 
which  are  energized  by  the  audio  fre- 
quency currents  and  which  actuate 
the  diaphragm. 

3)  The  permanent  magnet  of  con- 
stant polarity  which  exerts  a  pull  on 
the  diaphragm  at  all  times  and  which 
places  it  under  a  constant  stress  or 
tension. 

Current  from  the  radio  set  is  con- 
nected directly  to  the  coils  of  the  electro- 
magnets (2),  and  in  passing  through  these 
magnets,  the  current  causes  a  varying 
pull  on  the  diaphragm  which  sets  it  into 
a  state  of  vibration  exactly  proportional 
to  the  momentary  strengths  of  the  vary- 
ing current.  As  the  current  is  exceed- 
ingly small,  it  is  necessary  to  wind  these 
coils  with  hundreds  of  turns  of  very  fine 
wire  so  that  the  "ampereturns"  will  be 
sufficient  to  produce  the  desired  degree 
of  magnetization  of  the  poles  pieces. 
Owing  to  the  great  length  of  the  wire 
and  its  small  diameter,  the  resistance  is 
quite  high  when  compared  with  the 
resistance  of  the  phones  used  with  the 
ordinary  wired  telephone.  A  pair  of 
phones  in  a  double  headset  will  have  a 
resistance  ranging  from  2,000  to  6,000 
ohms,  but  it  should  be  remembered  that 
resistance  alone  is  no  index  of  the  sen- 
sitivity. It  is  the  number  of  turns  that 
counts,  not  the  resistance  in  ohms, 
although  in  exactly  similar  phones  the 
resistance  indicates  the  number  of  turns 
to  some  extent. 

The  magnet  coils  are  wound  on  iron 
cores  which  also  form  the  poles  of  a  power- 
ful permanent  magnet  (3).  The  stronger 
the  permanent  magnet,  the  more  sen- 
sitive will  be  the  phones,  but  the  "gyp" 
phone  makers  gracefully  shy  off  when 
questioned  on  this  point,  as  effective 
permanent  magnets  are  difficult  and 
expensive  to  make.  The  permanent 
magnets  exert  a  heavy  continuous  pull 
on  the  diaphragm,  and  in  a  manner  of 
speaking,  take  out  the  "slack"  and  con- 
trol the  vibration  of  the  diaphragm. 
Current  impulses  which  act  in  the  same 
direction  as  the  permanent  magnets 
add  to  the  deflection  of  the  diaphragm, 
while  impulses  acting  in  the  opposite 
direction  partly  neutralize  the  effect  of 
the  permanent  magnet  and  cause  the 
diaphragm  to  relax  in  proportion  to  the 
flow  of  current. 

At  this  point  I  wish  to  call  attention 
to  the  necessity  of  the  magnet  holding 
its  charge  indefinitely  without  weakening, 
even  when  the  phones  are  subjected  to 
severe  blows  and  falls  which  would  quickly 
demagnetize  a  permanent  magnet  of 
poor  construction.  The  steel  used  must 
be  glass  hard  to  properly  retain  the  charge, 
must  be  of  the  proper  grade  of  alloj 
steel  or  equivalent,  and  above  all  must 
be  properly  heat  treated  and  hardened. 


^ 


ou  can  make 
it  come  in 
clear 


(y^HEFJTS  a  lot  of  satis- 
^-^  faction  and  enjoyment 
in  perfect  reception.  Yet  it  does  not  come  merely 
with  having  a  good  loud  speaker. 

It's  the  work  of  Jefferson  Transformers  to  pro- 
vide  full,  smooth  amplification — furnish  the  loud 
speaker  with  the  proper  energy  so  as  to  assure 
the  greatest  volume  consistent  with  purity  of  tone. 

Proper  design  prevents  howling  and  distortion. 
You  want  more  than  noise  from  your  loud 
speaker;  that's  why  Jeffersons  are  made  to  a  ratio 
which  assures  clarity. 

Even  amplification  over  the  entire  musical 
range,  perfect  reproduction  of  the  voice  or  instru- 
ment— these  are  some  of  the  reasons  why  radio 
authorities  and  music  lovers  the  world  over  are 
recognizing  the  superiority  of  Jefferson  Trans- 
formers. 

Designed  by  a  concern  with  over  20  years  ex- 
perience  in  the  manufacture  of  high  grade  trans- 
formers of  all  descriptions.  Jefferson  Transform- 
ers meet  matched  construction  specifications. 

Ask  for  our  latest  ]efferson  circuits  including 
full  details  for  building  the  Jefferson  Baby 
Qrand  Superheterodyne  (6  tubes).  Write  today 

JEFFERSON  ELECTRIC  MFC  CO. 

438  South  Green  Street,  Chicago 


^Manufacturers  of 


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Teste!  and  Approved  hy  RADIO  AGE     f- 


58 


RADIO  AGE  for  January,   1*925 


StationsYouNeverHeard  Before 


thrti  scientifk tube tuning 


The  most  important  (and  most  neglected)  tuning  unit  on  your  set  is  the  tube.  It  is  the  one  thing1 
you  can  adjust  to  bring  weak  stations  to  audibility — to  eliminate  distortion  on  local  programs.  Coils 
and  condensers  are  easily  tuned  to  incoming  waves,  but  wave-length  isn't  everything.  The  antenna 
gets  distant  broadcasters  but  their  signals  never  reach  the  phones  unless  you  tune  the  tube  to  the 
different  characteristics  of  the  weak,  distant  stations.  Here  are  two  instruments  distinctly  de- 
signed to  improve  reception  through  their  ability  to  control  tube  action—  FIL-KO-LEAK to  tune  the 
grid  by  securing  correct  grid  bias — FIt-KO-STAT  to  tune  the  plate-filament  circuit  by  its  control  of 
electronic  flow.  Together  they  assure  you  maximum  audibility,  clearer  signals  and  freedom  from 
oscillations  and  other  tube  noises.    They  bring  in  station!  you  never  heard  J>e  fore. 


,     Individually  Calibrated^  $z!S 


JFIIrKO-STAT  *2 

•SClFNTIfKALTY  CORRKT  RADIO  RHEOSTAT       h  ~ 
/with  Battery  Switch  °$2.9o° 


You  will  get  stations  you  never  heard  before  with 
Fil-KO-Leak.  Clear  up  distortion  and  increase  volume, 
^'ou  can  "log"  your  Fil-KO-Leak  as  you  do  your  other 
tuning  units.  Each  Fil-KO-Leak  is  individually  hand 
calibrated  over  the  operating  range  of  all  tubes  J4  to  5 
fnegohms.  Set  it  for  specified  resistance  and  adjust 
it  for  best  results.  Resistance  read  in  megohms  through 
.panel  peep-hole.  (Base-board  mounting  furnished.) 
Resistance  element  constant,  accurate,  not  affected  by 
atmospheric  conditions,  wear  or  jarring.  Assures 
smooth,  gradual  control  of  resistance  and  correct  grid 
.lias.    Unconditionally  guaranteed. 


Tune  your  tube  filament  with  Fil-KO-Stat  and  receive 
stations  you  never  heard  before,  get  greater  distance, 
louder  signals,  sharper  tuning,  freedom  from  tube 
noises.  Fil-KO-Stat  is  the  only  rheostat  that  permits 
adjustment  over  the  entire  operating  range  of  all  tubes 
and  enables  you  to  get  maximum  audibility  in  phones 
or  loud  speaker.  And  now  the  improved  model  is  fitted 
with  battery  switch  that  attaches  to  the  regular  mount- 
ing screws.  l  Distinctly  signals  "on"  and  "off"  and 
enables  you  to'.lreak  circuit  without  changing  Fil-KO- 
Stat  adjustment.  Fil-KO-Stat  fits  any  type  tube  in  any 
hook  up.     Unconditionally  guaranteed. 


What  the  Broadcasters  are  Doing 

A  Pleasing  Voice  Isn't 
Enough! 

(Continued  from  page  31.) 
C^HPHE  announcer,  more  than  any  other 

■*-  entertainer  of  the  p  tiblic,  must  have 
an  innate  character,  a  very  positive 
intelligence,  and  a  friendly,  understand- 
ing voice,  which  informs  his  large  audi- 
ence as  easily  and  frankly  as  one  close 
personal  friend  would  inform  another. 
There  was  a  time  when  a  good  speaking 
voice  was  considered  the  only  requisite 
for  announcement  purposes,  but  in  my 
opinion,  that  time  is  passing,  and  passing 
very  rapidly.  The  executives  of  the  big 
broadcasting  companies  today  realize 
that  imagination,  character,  and  mental 
equipment  are  just  as  essential,  if  not 
more  so,  than  good  vocal  equipment." 

Apart  from  radio,  "Jacksy"  has  many 
hobbies,  which  include  chemistry,  physics, 
electricity,  music,  photography,  philos- 
ophy, psychology,  and  theosophy.  In 
April,  1924,  he  was  asked  to  prepare  his 
first  program  for  the  Canadian  National 
Railways  and  at  the  last  moment  dis- 
covered there  was  no  announcer.  He 
took    charge    himself    and    made    good. 

"How  do  you  know  you  made  good?" 
I  asked  him. 

"Because  no  one  recognized  my  voice,' 
he  replied,  with  a  sly  smile. 

Jackson's  success  can  be  attributed  to 
the  same  thing  that  brought  fame  to 
George  Hay,  the  "Solemn  Old  Judge" 
of  WLS,  and  formerly  with  WMC, 
Memphis;  to  the  same  intangible  some- 
thing to  be  found  in  the  ethereal  person- 
ality of  Thomas  A.  Cowan,  studio  man- 
ager of  Radio  Broadcast  Central,  WJZ- 
WJY,  New  York  City,  and  countless 
others  whose  voices  are  eagerly  awaited 
nightly. 


All  Mailto  Depl.  RAV25.  Harrisburg 


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"Best  Ever"  is  Verdict 
of  KYW  Fans 

Radio  fans  who  heard  RADIO  AGE's 
jazz  carnival  from  Station  KYW  Chicago, 
on  Saturday,  December  6,  reported  it  was 
one  of  the  "best  programs  ever  heard 
from  that  station." 

Axel  Christensen,  Banks  Kennedy,  Art 
("Goofy")  Linick,  Elizabeth  Berry,  Wan- 
da Goll,  George  Jatho  and  the  Banjo 
Boys,  Meyers  and  Sokol,  comprised  the 
"all  star"  cast  which  started  things  at 
midnight  and  kept  it  up  till  nearly  five 
o'clock  Sunday  morning.  California's 
receiving  the  program  unusually  clear 
caused  Announcer  Borroff  to  extend  the 
broadcasting  hours  considerably. 

Another  program  by  the  same  popular 
artists  will  be  on  the  air  again  Saturday, 
January  3.  So  don't  go  'way!  If  you 
want  something  special,  write  your  re- 
quest to  RADIO  AGE. 
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RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


59 


[  AGNATRON  Radio  Vacuum  Tubes  have  been  improved 
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RADIO  AGE  for  January,   1925 


A5TubeTuned  Radio  Frequency  Receiver 

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*     Tested  and  Approved  by  RADIO  AGE     * 


The  Magazine  of  the   Hour 

Some  Notes  on  the  Midget 
Reflex 

(Continued  from  page  48) 
of  the  wires  dotted  for  the  assistance 
of  those  who  wished  to  simplify  matters 
by  grounding  part  of  the  circuit  to  a 
metal  panel.  It  seems  almost  impossible 
that  such  mistakes  could  occur,  but 
they    have — and    repeatedly. 

Now  we  come  to  the  subject  of  free 
tube  oscillations,  the  inherent  difficulty 
with  reflex  circuits.  With  the  tube  in 
free  oscillation,  radio  frequency  ampli- 
fication is  impossible.  In  this  set,  cor- 
rections can  be  made  by  adding  a  few 
turns  to  the  primary  coil  (LI)  thus  re- 
ducing the  radio  frequency  transforma- 
tion ratio  and  the  oscillations  at  the 
same  time.  This  ratio  varies  somewhat 
with  different  makes  and  ratios  of  the 
audio  transformer  (AT)  and  individual 
adjustment  must  be  made  in  each  case 
by  adding  turns  to  (LI).  In  extreme 
cases  I  have  been  forced  to  use  as  high 
as  25  turns  on  (LI)  when  highly  in- 
ductive   transformers    were    used. 

It  must  be  understood  that  the  nega- 
tive pole  ( — )  of  the  "C"  battery  must  be 
connected  to  the  grid  connection  (G) 
of  the  tube  socket.  If  the  polarity  is 
reversed  the  set  will  not  operate  at  all. 
This  is  known  as  giving  a  "negative  bias 
to  the  grid."  Two  cases  of  reversed 
polarity  were  discovered,  two  defective 
crystals,  and  a  short  circuited  condenser 
(Kl)  which  was  damaged  by  heat  while 
the  condenser  was  being  soldered  into 
circuit.  When  soldering,  be  very  care- 
ful not  to  overheat  the  condensers. 

Of  course  we  had  our  old  soldering 
difficulties  in  evidence.  In  one  set 
examined  by  the  writer,  there  were  only 
three  wires  actually  soldered,  the  re- 
mainder simply  being  stuck  together 
with  the  rosin  soldering  flux.  The  con- 
ductivity of  such  joints  is  zero.  Use  a 
hot  soldering  copper  which  has  a  clean 
and  shining  point  well  "tinned"  with 
solder.  A  cool  soldering  iron  will  melt 
out  the  rosin  flux  but  will  not  melt  the 
metal  solder,  thus  giving  an  impression 
that  the  joint  is  soldered  when  it  is  not. 
After  soldering  a  joint  shake  it  roughly 
by  hand.  If  it  is  stuck  only  by  the  flux 
it  will  break  off.  If  properly  soldered 
it   will   withstand   considerable   abuse. 

When  the  set  is  in  proper  working 
order  it  will  howl  and  shriek  violently 
whenever  the  catwhisker  is  lifted  from 
the  crystal.  As  a  rule,  continued  howl- 
ing is  due  to  ,an  imperfect  crystal  or  to 
improper  adjustment  of  the  catwhisker. 
If  the  reception  improves  when  the  cat- 
whisker is  lifted  from  the  crystal  then 
the  detector  is  probably  connected  to 
the  wrong  side  of  (K2)  as  already  de- 
scribed, the  condenser  (K2)  may  be  short 
circuited  by  soldering,  or  the  detector 
may  be  defective.  Free  oscillations  in 
the  tube  will  also  cause  similar  effects. 


CABINETS 

If  you  are  interested  in  a, 
radio  cabinet  in  which  is 
combined  both  beauty  and 
practicability,  just  write 

LAKESIDE  SUPPLY  C0.: 

Dept.  R 

73  West  Van    Buren    St. 

CHICAGO,  ILL. 

Telephone,  Harrison  3840 


The    'Magazine  of  the  Hour 


61 


RADIO  AGE  for  January,   192S 


Keeping  up  With  the  French 
Radio  Fan 

(Conlinurd  from  page  20) 
made  to  turn  slowly  when   the   knob   is 
rotated.     The  purpose  of  the  spring  is  to 
maintain    a    constant    pressure    of    the 
grooved  pulley  on  the  bakelite  disc. 

The  vacuum  tubes  are  of  the  three- 
electrode  type.  The  prongs  are  slotted 
and  are  engaged  into  female  parts.  No 
error  is  possible  in  placing  them  as  prongs 
and  other  parts  are  disposed  in  a  special 
manner.  This  type  of  prongs  is  superior, 
electrically,  to  the  American  type.  The 
contact  is  made  on  a  large  surface  and 
practically  no  trouble  is  experienced  from 
this  mode  of  connection. 

A  combined  variable  grid  leak  and 
variable  condenser  has  just  been  intro- 
duced on  the  market.  Such  a  combina- 
tion is  valuable  in  getting  the  best  out 
of  any  given  tube.  Special  mention  must 
also  be  made  of  a  very  good  loud  speaker 
of  an  artistic  design.  The  diaphragm 
of  the  loud-speaking  unit  tramsits  its 
vibration  to  a  pleated  parchment  disc, 
giving  very  pure  reproduction  free  from 
any  metallic  noise. 

The  first  radio  sets  were  equipped 
with  the  lamps  on  top  of  the  set;  they 
were  thus  unprotected,  resulting  in 
breakage;  and  the  glare  was  objection- 
able. The  new  models  are  of  the  "piano" 
type,  a  hinged  cover  protecting  the 
lamps.  The  latest  invention  is  a  set 
which  may  be  switched  on  110  volts 
D.  C.  or  A.  C,  eliminating  storage 
battery  or  dry  cells. 


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the  building)  as  near  as  practic- 
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enters  the  building.  The  pro- 
tector shall  not  be  placed  in  the 
immediate  vicinity  of  easily  ignit- 
able  stuff,  or  where  exposed  to 
inflammable  gases  or  dust  or 
Byings  of  combustible  materials. 
The  protective  device  shall  be 
an  approved  lightning  arrester 
which  will  operate  at  a  potential 
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less. 

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62 


RADIO  AGE  for 


aniiarv. 


192; 


The,  Magazine  of  Hie  Hour 


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A  Really  Efficient  Portable 
Receiving  Set 

( Continued  from  page  22) 
to  remain.  Then  it's  a  case  of  reversing 
the  primary  connections  of  transformer 
"B"  or  "C".  As  a  rule,  the  best  way  is 
to  wire  up  the  audio  transformers  ac- 
cording to  the  manufacturers'  markings. 
This  usually  places  the  outside  end  of 
the  secondary  on  the  grid,  its  inside  or 
"beginning"  on  the  negative  filament; 
the  outside  or  "end"  of  the  primary 
winding  to  the  plate  and  its  inside  or 
"beginning"  to  the"B"  battery  positive. 
Ordinary  bell  or  annunciator  wire  is 
most  conveniently  used  to  make  the 
connections  and  it  is  then  very  easy  to 
"swap"  the  primary  connections.  The 
difference  in  operation  is  due  to  the 
opposition  of  the  primary  coils  when 
they  are  properly  reversed  and  audio 
oscillation  is  thereby  stopped.  There 
is  also  a  difference  in  the  radio  frequency 
results,  which  should  not  be  treated  tWl 
the  audio  howling  has  been  eliminated. 
The  change  in  R.  F.  amplification  is  due 
to  a  difference  in  capacity  between  the 
primary  or  secondary  winding  of  the 
R.  F.  transformer  and  the  filament  side 
of  the  audio  transformers,  this  difference 
being  caused  by  the  reversal  of  the 
primary  connections.  If  a  certain  prim- 
ary reversal  stops  the  howling  but  de- 
creases signal  volume,  especially  on  a 
DX  station,  it  is  merely  necessary  to 
use  a  larger  size  by-pass  condenser  at 
C-2  or  C-3. 

R.  F.  Transformers 

The  radio  frequency  transformers  are 
to  be  connected  exactly  as  their  makers 
recommend,  except,  of  course,  that  in- 
stead of  a  connection  directly  to  the 
positive  "B"  battery,  this  is  made 
through  the  audio  transformer's  primary 
and  similarly  the  negative  filament 
connection  is  through  the  secondary  of 
the  audio  transformer. 

Inverse  duplexing  was  tried  also,  but 
inasmuch  as  more  difficulty  was  met  in 
quieting  the  howling  at  audio  frequencies, 
the   straight   reflex  was   finally  selected. 

If  the  speaker  is  placed  in  front  or 
turned  aside,  such  trouble  usually  ceases 
and  it  is  not  encountered  at  all  when 
the  portable  set  is  made  up  with  the  horn 
exposed  and  tubes  concealed  or  shielded 
from  air  vibration  by  the  panel.  The 
lay-out  illustrated  operates  very  well 
on  the  cigar  box  loop,  distant  stations 
in  Canada,  Chicago,  and  other  points 
being  heard  with  good  volume  on  the 
loud  speaker  in  the  writer's  New  Jersey 
location.  The  builder  of  the  portable 
set  would  doubtless  employ  a  larger  loop 
than  this  and  results  with  a  larger  loop 
are  very  much  better.  The  sharp  direc- 
tional effect  of  the  cigar  box  loop  is  sur- 
prising in  its  effective  elimination  of  a 
loud  local  station  and  the  interception 
of  some  faint  DX  fellow  when  their 
directions  are  at  right  angles  to  each 
other. 

The  final  installation  of  the  portable 
is  in  a  suit-case  measuring  about  10  by 
16  inches,  including  speaker,  batteries, 
set  and  a  spiral  loop  wound  on  hard  rubber 
rods  and  mounted  in  the  cover  of  the 
suit-case. 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


63 


Pure 

Inductances 
for  Low  Loss 
Receivers 


\yiUCH  is  being  said  about  the  necessity 
*■**■  of  good  parts,  especially  of  condensers. 
Inductances  are  likewise  of  extreme  import- 
ance for  efficiency . 
Pfanstiehl  Pure-In- 
ductances are  good 
because: 

^  1 .  Air-cored  means 
no  absorption  of  sig- 
nal strength; 

2.  Stagger  wound 
means  no  appreciable 
distributed    capacity. 

3.  Vernier  control 
of  adjustment  means 
distance  getting. 


;Pfanstiehl 
Variometer,  P-301 


"THE  Pfanstiehl  Variometer  with  two  50 
1  tjurn  untapped  coils  as  a  variometer  with 
PERFECT  RATIO  OF  INDUCTANCE. 
$4.75  at  your  dealer's. 

"THE  Pfanstiehl  Variocoupler  P-300  is  an- 
1  other  efficient  unit.  Using  this  unit  in  our 
"efficiency  hookup" 
furnished  with  unit 
a  Wisconsin  radio  fan 
picked  up  Hawaii! 
Let  us  suggest  that 
you  improve  your 
favorite  circuit  with 
this  variocoupler. 
$  vOO  at  your  dealer's. 
THE  new  Pfanstiehl 
1  "Three-Circuit" 
Tuning  Unit.  P-302, 
solvesthe  problems  of 
radiation  and  selec- 
tivity in  the  regener- 
Pfanstiehl  Vario-  ative  circuit.  $5.00 
couoler,  P-300  at  your  dealer's. 

Other   Pfanstiehl   Pure   Inductances  are: 


Tun 


List 
Price 
$0.55 


P-201 25 

P-202 35 

P-203 50  .65 

P-204 75  .74 

P-205 100  .90 

P-206 150  1.10 

Pfanstiehl  Ultra  Audion $0.95 

Pfanstiehl  Reinartz $1.75 


Wave 
Length 
100-340 
125-470 
170-650 
220-960 
300-1300 
470   1980 


V 


""HE  P-600  Pfan- 
L  stiehl  Oscillator 
for  super-heterodynes 
oscillates  sharply  and 
steadily  and  improves 
the  hookup.  For  any 
intermediate  trans- 
formers (2,000—10,- 
000  meters.)  $6.00 
3t  your  dealer's. 


Pfanstiehl 
Oscillator,  P-600 


The 

PFANSTIEHL 
RADIO  CO. 

Highland  Park     -     Illinois 

Chicago  Office 

1001  W.  Washington  Boulevard 

Tel.  Haymarket  8010 


' '  The  Hidden  Voice : ' '     An 
Unusual  Radio  Story 

( Continued  from  page  30) 
impatiently.  "The  concert  is  probably 
corning  out  of  the  carriage  now.  If  I 
can  get  on  the'air  right  away,  before  the 
kidnapper  gets  wind  of  the  radio  set  in 
the  baby  carriage,  we  can  scare  the  man 
or  woman  who's  adbucted  the  kid  and 
maybe  upset  his  plans.     Is  that  clear?" 

A  Dramatic  Moment 

TTORNADAY  had  a  sense  of  humor 
-*--*-  and  he  appreciated  the  possibilities 
of  Jim's  plan.  He  wanted  to  know  if 
Jim  was  sure  the  set  was  tuned  to  Station 

W ;  and  he  was  in  turn  reassured 

that  the  tubes  were  turned  on  full  volume 
for  W and  nobody  else. 

Larry  ran  into  the  operating  room. 

"  Stop  everything  !  "  he  whispered 
hoarsely.  The  operator,  amazed  but 
sensible  enough  to  obey  orders,  cut  off 
the  switch  as  a  local  prima  donna  was 
about  to  begin  the  first  verse  of  her 
latest  "masterpiece." 

Then  Larry  ran  into  the  studio,  ex- 
plained matters  hurriedly,  and  motioned 
to  Jimmie  to  seat  himself  before  the 
microphone  and  "do  his  stuff. "  The 
surprised  artists  reluctantly  took  seats 
in  the  corners  of  the  studio,  wondering 
what  was  about  to  happen. 

"Go  to  it,  Jim,"  Larry  finally  said. 
"If  this  will  help,  it'll  be  a  tremendous 
boost  to  the  station.  Ready?  All  right. 
Shoot!" 

Tense,  and,  only  slightly  nervous,  Jim 
faced  the  "vieled  lady."  Gathering 
his  wits  and  assembling  his  practiced 
speech  coherently,  he  began  speaking  in 
a  steady  though  imperative  tone: 

"Help,  help,  help!  I'm  being  kid- 
napped. The  person  who  is  pushing  this 
carriage  kidnapped  me.  Help!  The 
police  are  looking  for  me.  Help!  !  Take 
me  back  to  my  mamma!  I  want  my 
mamma!" 

Chapter  II 

"The  Baby's  'Stomach' " 

J3EOPLE  did  wonder  very  much  at  the 
■*-  sounds  they  heard  coming  from  baby 
Edward's  carriage  as  they  passed  it  on 
the  street.  They  gazed  with  astonish- 
ment, first  at  the  sweet  face  of  the  infant, 
then  at  the  plainly  dressed,  hard-featured 
woman  behind. 

The  latter,  Julia  Murray,  was  not  a 
professional  baby  snatcher.  She  had  a 
record  of  shop-lifting  and  other  forms 
of  petty  theft,  which  had  not  proved  as 
lucrative  as  her  growing  greed  demanded, 
and  this  crime  was  a  new  venture  on  her 
part.  She  had  a  friend  who  would  help 
her,  and  together  they  might  make  a 
considerable  "haul."  So  on  she  walked, 
shaping  her  plans  as  she  went,  when 
suddenly  there  came  a  sound,  that  of  a 
human  voice,  from  the  carriage  that 
sent  violent  chills  through  her  frame. 

"Help,  help,  help!  I'm  being  kid- 
napped. The  person  who  is  pushing  this 
carriage  kidnapped  me.  Help!  The 
police  are  looking  for  me.  Help!  Take 
me  back  to  my  mamma!  I  want  my 
mamma  ! " 

(Continued  on  page  65) 
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Receiver.  It  is  manufactured  by  the 
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for  the  Phenix  Radio  Corporation,  who 
will  furnish  any  information  concerning 
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Timmons  Talker  Wins  Fans 

If  you  haven't  heard  the  Timmons 
Talker,  made  by  the  Timmons  Radio 
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The  Timmons  Talkers  are  made  in  two 


Stewart  C.  Whitman  Has  New 
Invention 

Radio  fans  everywhere  will  be  inter- 
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door antenna  by  its  manufacturers. 

Mr.  Whitman,  inventor  of  the  Para- 
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types;  the  Type  "A"  adjustable  loud- 
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than  those  on  watch-cases,  permitting 
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is  removable  for  the  placing  of  A  or  B 
batteries  around  the  reflecting  horn. 

The  Timmons  Corporation  is  also 
marketing  a  B-Battery  Eliminator,  which 
gives  accurate  control  of  the  plate  vol- 
tages of  all  tubes.  They  are  constantly 
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New  "Perfect  Contact"  Socket 

Announcement  is  made  by  The  Cutler- 
Hammer  Mfg.  Company  of  Milwaukee, 
Wisconsin,  that  they  have  recently  put 
on  the  market  a  new  and  distinctly  de- 


signed socket  which  provides  a  perfect 
contact  for  radio  reception.  It  is  the 
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research  and  contains  features  not  found 
in  any  other  type. 

The  tube  is  simply  pushed  down — not 
twisted — into  the  socket,  thereby  pre- 
venting any  chance  of  severing  the  bond 
between  glass  and  base  of  tube. 


RADIO  AGE  for  January,  1925 

(Continued  from  page  63) 

''Help,  help,  help!"  called  the  voice 
"I'm  being  kidnapped.  The  person  who 
is  pushing  this  carriage  kidnapped  me. 
Help!  Take  me  back  to  mamma.  I 
want  my  mamma." 

It  was  awesome  enough  to  make  many 
women  unstrung.  But  Julia  was  not  of 
that  nature.  Nevertheless,  she  was  non- 
plused. She  stopped  and  looked  at 
the  baby,  who  ceased  to  bite  at  his 
zwieback  long  enough  to  utter  a  string 
of  self-satified  "coos." 

What  could  it  mean?  Had  her  ears 
deceived  her?  With  nervous  hope  that 
she  was  the  victim  of  an  illusion,  or 
that  the  cry,  whatever  it  was,  would 
not  be  repeated,  she  stepped  back  to 
the  push-handle  again. 

But  her  hope  was  vain.  Half  a  minute 
later  the  cry  for  help  came  once  more 
from  the  pillows  and  quilts,  this  time 
more  vigorously. 

"Help,  help,  murder!  I'm  being  kid- 
napped. My  kidnapper  is  going  to  kill 
me.  Rescue  me.  Take  me  back  to  mam- 
ma." 

What  Can  It  Mean  ? 

This  time  a  well  dressed,  middle  aged 
woman  approached  near  enough  to  hear 
most,  if  not  all,  of  "the  infant's"  plea. 
She  looked  as  if  she  was  going  to  faint 
or  scream  as  she  passed,  but  she  did 
neither. 

The  cries  for  help  continued  at  fre- 
quent intervals  from  the  carriage,  and 
the  woman  pushed  along  as  rapidly  as 
she  could  without  breaking  into  a  run. 
If  she  had  dared,  she  would  have  aban- 
doned the  child  on  the  street  and  thus 
escaped  the  ever  increasing  embarrass- 
ment and  danger,  but  there  were  too 
many  persons  passing  for  her  to  resort 
to  such  move.  She  turned  several  cor- 
ners in  the  hope  of  finding  less  frequented 
avenues,  but  with  poor  success. 

"Help!"  "Murder!"  "Police!"  "Kid- 
nappers." "Thieves,"  were  some  of  the 
cries  and  words  that  seemed  to  pour 
almost  continuously  from  the  infant's 
lungs,  while  passers-by  stared  and  shied 
at  her  and  the  babe  as  if  in  doubt  whether 
to  flee  as  from  a  ghost  or  put  in  a  call  for 
psychopathic  ambulance.  Finally  Julia 
broke  into  a  run  and  virtually  flew  down 
the  sidewalk,  pushing  the  carriage. 
(To  be  concluded  in  Februarv 
RADIO  AGE; 


The  Magazine  of  the  Hour 


65 


Arthur  B.  McCullah,  who  created 
a  sensation  at  the  Chicago  radio 
show,  and  who  has  been  a  keen 
student  of  the  latest  in  super-heter- 
odynes, will  present  a  new  article 
giving  all  the  latest  developments 
of  the  popular  "super"  in  the  Feb- 
ruary RADIO  AGE.  Watch  the 
next  issue  for  this  up-to-the-minute 
article. 


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66 


RADIO  AGE  for  January,   V)*. 


The  Magazine  of  the  Hour 


ykriMe  Condenser 


LOW  LOSS 

(Practically  no  Loss)  A  FACT 

N:w  distances — new  thrills  are  yours  with 
D.  X.  L.  Straight-line  Low  Loss  Condensers. 
For  Low  Loss  is  a  definite  fact. 
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infinite  precision  upon  the  exclusive  D.  X. 
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Manhattan  Jt.  Loud  Sneaker 10.00 

Amettran  Transformers 5.75 

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A  6-Tube  Baby  Grand  "Super 


(Continued  from  page  17) 


method  of  wiring  other  than  merely  the 
appearance  of  the  set.  At  first  glance  it 
may  seem  to  introduce  complications  for 
the  average  fan.  This  is  not  the  case, 
however,  for  after  you  have  run  the  first 


You  now  have  a  very  convenient 
method  of  attaching  your  filament  leads 
directly  to  the  binding  posts  without  the 
necessity  of  drilling  separate  holes.  The 
sockets  used  bv  the  writer  are  the  Ben- 


two  or  three  base  wires,  you  will  have  jamin  type,  having  spring  bases.  Other 
little  or  no  difficulty.  It  should  be  re-  leads  not  going  to  sockets  will,  of  course, 
membered  that  contrary  to  most  wiring  require  separate  holes  through  the  base- 
plans,  you  have  no  grid  or  plate  leads  to  board.  Great  pains  have  been  taken  in 
contend  with,  besides  those  appearing  laying  out  the  two  baseboard  drawings 
above  the  baseboard;  and  in  no  case  will  shown  with  this  article,  so  if  you  follow 
it  be  possible  to  run  grid  and  plate  leads  them  carefully,  very  little  comment  need 


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parallel  to  each  other  or  to  any  other 
leads  in  the  set.  The  oft  repeated  in- 
junction of  keeping  grid  and  plate  leads 
as  far  separated  as  possible  and  not 
parallel  can  thus  be  forgotten  when 
wiring    underneath    the    baseboard. 

All  that  you  have  to  contend  with  are 
the  filament  leads  and  "b"  battery  leads. 
The  arrangement  of  the  baseboard  pre- 
cludes the  possibility  of  interaction  be- 
tween any  of  these  leads.  By  studying 
the  baseboard  photograph,  it  will  be  seen 
that  the  filament  leads  are  carried  directly 
through  the  baseboard  in  every  case  and 
that  the  plate  and  grid  leads  remain  above 
the  baseboard  and  go  directly  to  the 
transformers,  or,  as  the  case  may  be,  to 
the  oscillator  coil. 

As  soon  as  you  have  placed  the 
apparatus  on  a  baseboard,  using  brass 
machine  screws  and  nuts  for  the  purpose, 
drill  your  holes  for  the  filament  leads  as 
close  to  the  binding  posts  as  possible. 
This  also  applies  to  all  other  leads  which 
go  from  transformers  to  other  portions  of 
the  circuit.  Be  sure  to  stagger  the 
apparatus  as  shown.  The  baseboard 
arrangement  has  in  mind  condensing  to  a 
minimum  amount  of  space  and  at  the 
same  time  insuring  the  shortest  possible 
grid  and  plate  leads.  The  intermediate 
frequency  transformers  used  are  shielded 
and  are  of  the  iron  core  type  and  can  be 
worked  very  close  together  without  inter- 
stage coupling.  However,  the  baseboard 
arrangement  has,  among  other  advan- 
tages, that  of  keeping  any  possible  inter- 
stage reaction  to  the  smallest  possible 
minimum. 

While  this  set  as  originally  built  was 
planned  so  that  holes  were  to  be  drilled 
through  the  baseboard  for  the  various 
leads,  yet  in  practice  it  will  be  found 
that  a  rather  simpler  method  can  be 
used;  at  least  in  the  case  of  the  filament 
leads  going  to  the  sockets.  Remove  the 
two  filament  binding  posts  from  each  of 
the  sockets,  and  after  placing  the  sockets 
in  their  respective  positions  on  the  base- 
board, mark  the  baseboard  with  small 
center  punch  for  holes  through  the  base- 
board, directly  underneath  the  filament 
post  holes.  As  most  binding  post  screws 
extend  considerably  above  the  binding 
post,  you  will  probably  find  that  the 
binding  post  screws  will  be  plenty  long 
enough  to  pass  through  the  baseboard, 
as  well  as  the  tube  socket,  and  still  leave 
enough  threads  extending  above  the 
socket  for  the  binding  post.  Of  course, 
the  screw  holes  on  the  under  side  of  the 
panel  should  be  counter-sunk  so  that  the 
heads  of  these  screws  will  not  extend 
beyond  the  bottom  face  of  the  baseboard. 
*     Tested  and  Approved  by  RADIO  AGE     * 


be  made  along  this  line  except  to  repeat 
that  only  those  wires  that  appear  above 
and  below  the  baseboard  are  shown  in  the 
respective    drawings    for    each    of   these 

Securing  Leads 
r  I  ''HERE  are  two  or  three  leads  which 
*-  are  rather  too  long  to  support  them- 
selves; these  should  be  held  in  place  by 
a  loop  of  copper  wire  passed  through  holes 
on  either  side  of  the  lead.  Make  sure 
that  these  loops  do  not  occur  underneath 
any  of  the  transformers  or  other 
apparatus,  so  as  to  cause  short  circuits 
or  other  complications.  Usually  you 
will  find  that  the  long  leads  can  be  run 
underneath  the  shorter  leads  by  bending 
"U"  shaped  loop  in  the  short  lead  directly 
over  the  intersection  of  the  two  leads 
and  place  a  short  piece  of  "spaghetti" 
on  the  longer  lead  so  as  to  insulate  the 
leads  from  each  other.  The  "spaghetti" 
can  be  anchored  in  place  by  using  a  little 
shellac. 

By   consulting   the    photographic    and 
baseboard   views   of   this   set,   it   will   be 
seen  that  the  upper  loop  binding  post  is 
connected  directly  to  the  stator  plates  of 
the  right   hand    (loop  condenser).     This 
lead  lays  flat   against   the  panel  and   is 
connected  at  its  mid-point  to  the  rotor 
plates  of  the  small  9  plate  Chelten  con- 
denser.    The  other  lead  from  this  con- 
denser  goes   direct   to   the   plate   of  the 
second    tube    (detector)    and    the    plate 
terminal  of  the  first  intermediate  trans- 
former,  which,  as  you  will   note,  are  in 
common.     The  rotor  plates  of  the  loop 
condenser   are  connected  to  the  bottom 
binding  post  on  the  left  end  of  the  panel 
as  well  as  to  the  input  side  of  the  oscillator 
coil.     The  4  J.  2  volt   bias  battery  shown 
between  the  two  variable  condensers  is 
by-passed    by    means    of    a    .0025    fixed 
condenser  and  has  its  negative  side  con- 
nected  to   the    middle   binding   post   on 
the   left    hand    end    of   the    panel.     The 
positive  side  of  this  bias  battery  is  con- 
nected to  the  negative  side  of  the  filament 
circuit.     The  oscillator  condenser  shown 
at  the  extreme  end  of  the  panel  bridges 
the  plate  and  grid  of  the  first  (oscillator) 
tube  as  well  as  the  oscillator  coil. 
"B"  Voltage  Is  90 
The  battery  shown  in  the  photograph 
of  the  set  between  the  loop  condenser  and 
the  audio  transformer  places  a  negative 
bias  on  the  (last)  audio  tube.     The  volt- 
age is  correct  for  90  volts  of  "B"  battery; 
the  other  bias  battery  shown  on  the  back 
of  the  baseboard  lying  on  its  side  furnishes 
negative  bias  to  the  first  four  tubes.     A 
grid  leak  and  grid  condenser  are  used  on 
(Turn  to  page  75) 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


67 


Why  a  Musical  Director 
Never  SMILES 

(Continued  from  page  35.) 
ately  planned  a  lengthy  recital,  due  no- 
tice of  which  was  forwarded  to  us.     She 
appeared  per  schedule  and  sang  one  song. 

It  looked  like  something  was  due  to 
happen   to   an   otherwise  good   program. 

With  regret,  she  failed  to  appear 
again  that  evening.  As  we  signed  off 
for  that  particular  hour,  a  veritable  aval- 
anche of  Wailing  smote  the  ear.  We  were 
no  gentlemen,  we  were  the  "short  and 
uglies,"  we  failed  in  believing  that  any 
one  who  sang  with  teeth  tightly  clenched 
in  a  wee,  squealing  manner  was  going  to 
stand  for  such  treatment,  and  much  more. 

Then  the  Artist  Type 

HAVING  up  to  this  time  said  nothing, 
made  no  comment  on  the  singing, 
offered  no  excuse  save  that  the  program 
was  so  full  we  hadn't  had  time  for  more 
than  one  number  from  the  incipient 
Galli-Curci,  we  bowed  the  head  to  the 
blast  and  tried  to  appear  meek  and 
lamblike.  The  tirade  continued  for  more 
than  an  hour.  In  fact,  it  continued  until 
one  of  the  engineers,  annoyed  by  the 
threat  of  the  lady's  brother  to  do  bodily 
injury  to  him,  picked  up  a  broom  and 
industriously  began  to  raise  a  cloud  of 
dust  from  the  concrete  floor. 

A  typical  example,  that,  of  the  "artist" 
type.  Had  the  soprano  in  question 
really  been  good  the  episode  would  not 
have  happened.  If  the  program  had  been 
filled  the  real  artist  would  have  under- 
stood— as  they  often  do — and  would 
have  been  booked  for  a  later,  more 
propitious  occasion. 

Woe  No.  3,  as  we  see  it,  is  the  con- 
tinual worry  for  fear  those  of  the  real 
artists  booked  may  not  appear  in  time 
for  the  opening  of  the  concert  or  decide 
at  the  last  moment  not  to  appear  at  all. 
(Turn  to  next  page) 


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For  design,  construction,  performance  and  ease  of  operation  the  SHACTON  is  the 
most  remarkable  achievement  in  present  day  radio.  The  most  important  feature  and 
without  a  doubt  the  cause  of  SHACTON'S  success  lies  in  the  fact 

that  Low  Loss  instruments  of  thehighest  grade  are  used  through-  r  R  .  C  £ 
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KHJ 
Los  Angeles,    Cal. 

We  are  glad  to  confirm  your  report  of  recep- 
tion of  our  program. 

John  S.  Daggett, 
"Uncle  John," 
Mgr.,  Times  Radio  Staff. 


£ 


General  Electric 
Company 


Pacific  Coast 
Broadcasting  Station 
KGO 


5555  E.  14th  St. 
Oakland,  Cal. 
Sept.  11,  1924. 
Mr.  T.  J.  Kennedy, 
1360  University  Ave.,  New  York,  N.  Y. 

We  are  glad  to  confirm  your  reception  of 
KGO  on  the  evening  of  Sept.  6  as  we  were 
broadcasting  the  opera  "Carmen." 

We  always  appreciate  hearing  from  our 
radio  listeners  and  hope  that  you  will  be 
able  to  pick  up  KGO  regularly. 
Yours  very  truly, 

Jennings  Pierce, 
Radio  Broadcasting  Pub.  Dept. 


DX  Fans!  Confirmations  Stop  All 
"Doubting  Thomases" 

Confirmations  of  Stations  Received  from 
New  York,  N.  Y.t  with 

KENNEDY  TUNER 

DX  Fans!  If  you  want  real  results,  get  a 
KENNEDY  TUNER  AND  HAVE  THE 
WHOLE  U.  S.  A.  AT  YOUR  FINGER  TIPS. 

Only  one  dial  to  get  stations  and  the  other  to  increase  or 
decrease  volume.  Kennedy  Tuner  is  used  in  place  of  vario- 
coupler,  variometer  and  honeycomb  coils,  saving  the  cost  of 
over  $9.00  worth  of  unnecessary  junk  that  is  in  most  receiv- 
ing sets,  and  no  dead  end  losses. 


KFI 
Los  Angeles,  Cal. 

Thanks  for  your  letter  received.  Yes, 
"The  Minuet,"  by  Louis  Parker,  was  broadcast 
from  the  Anthony  station  during  the  late 
program. 

Yours,  Radio  KFI. 


Tuner 

Including  Globe 
Trotter  Diagram 


GUARANTEE: 

If  not  satisfied 
after  30  days,  we 
will  cheerfully 
return  your 
money. 


General  Electric 

Company 

Pacific  Coast  5555  E.  14th  St. 

Broadcasting  Station  Oakland,  Cal. 

KGO  Sept.  4,  1924. 

Mr.  Vincent  T.  Kenney, 
124  W.  96th  St.,  New  York,  N.  Y. 

We  are  glad  to  confirm  your  reception  of 
our  late  program  from  the  Hotel  St.  Fran- 
cis on  the  morning  of  August  27th. 

We  are  always  glad  to  answer  any  ques- 
tions of  our  radio  friends  and  hope  you  write 
in  often  with  your  comments. 
Yours  very  truly, 

Jennings  Pierce, 
Radio  Broadcasting  Pub.  Dept. 


KLZ  Denver,  Colo. 

We  are  pleased  to  acknowledge  receipt  of 
your  report  of  reception  of  our  phone  station. 
We  have  placed  a  tack  in  our  map  for  you. 

Reynolds  Radio,  Inc. 


Send  for  Free  Diagram 

T.  J.  KENNEDY 

RADIO  GLOBE  TROTTER 

1360  University  Ave.,  New  York,  N.  Y. 


2-LO,  London,  Eng. 

We  beg  to  acknowledge  your  reception  of  our 
program. 

Yours  faithfully  for  the 
British  Broadcasting  Co.,  Ltd., 
Jr.  Director,  London  Station,  C.  C.  H.  King 


*     Tested  and  Approved  by  RADIO  AGE     * 


68 


RADIO  AGE  for  January,    1925 


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The  Magazine  of  the  Hour 

(Continued  from  preceding  page) 
The  concert  is  announced,  the  program 
is  arranged  to  the  musical  director's 
satisfaction,  the  time  is  set  for  five  min- 
utes from  now — and  no  talent!  Worra, 
worra! 

"Ah,  here  they  are.  Three  minutes  to 
go.  Please  hurry.  What're  you  going 
to  do  first?  What's  that  first  name 
again?  There  goes  the  'on  the  air' 
signal.  The  red  light'll  be  on  in  a  minute. 
What's  your  next  number?  What's 
the  name  of  your  accompanist?  Here 
we  go.   ..." 

Some  time  since  a  certain  manager- 
clerk  in  a  school  of  music  kindly  promised 
us  seven  persons  for  a  program.  Five 
hours  before  they  were  to  arrive — it  was 
on  a  holiday — we  learned  we  must  be 
"off  the  air"  for  a  matter  of  two  hours 
just  at  the  time  the  manager-clerk's 
seven  were  to  appear.  The  concert  had 
started  and  the  seven  were  supposed  to 
"go  on  the  air"  a  half  hour  later. 

A  Terrible  Outrage 

They  arrived  seven  minutes  late,  save 
for  one  soprano  who  ought  to  make  a 
name  for  herself  because  she  had  so 
much  common  sense. 

When  we  broke  the  news  the  manager- 
clerk,  feeling  important  before  his  charges, 
no  doubt,  burst  into  a  tempest  of  rage. 
He  snarled.  He  growled.  He  sneered. 
He  ended  up  by  saying  that  his  seven 
could  wait  the  two  hours  if  they 
wished,  but  he,  for  one,  strongly  urged 
them  to  leave  the  musical  director  flat  on 
his  back,  gasping  for  success.  He  over- 
looked the  fact  that  it  had  been  impossible 
for  us  to  notify  his  seven  charges,  since 
we  had  not  known  their  address  or  phone 
numbers  and,  it  being  a  holiday,  he  had 
not  been  in  his  office,  where  we  might 
have  reached  him. 

Meanwhile  the  musical  director  has 
one  eye  on  the  clock,  thinking  of  the 
waiting  thousands  who  will  not  wait 
long,  another  on  the  dilatory  performer. 
Between  trying  to  straighten  out  his 
crossed  eyes,  hurry  the  proceedings  with- 
out recording  strong  language  in  the 
"mike,"  and  calm  himself,  he  is  lucky 
if  he  doesn't  begin  saying  "da  da"  and 
ask  for  a  rattle. 

Happy  [Sometimes] 

But  if  the  woes  of  a  musical  director 
are  many  and  sore — we  have  mentioned 
but  a  few — his  joys  far  offset  them. 
Most  artists  are  fine  people,  willing  to 
help  amuse,  instruct  and  charm  the 
millions  of  the  radio  theater  and  concert 
hall,  happy  to  do  their  bit  toward  making 
broadcasting  the  eighth  wonder  of  the 
world,  quite  conscious  of  the  personal 
element  and  of  the  need  for  whole  hearted 
co-operation  between  the  station  man- 
agement and  themselves  and  altogether 
a  mighty  good  set  of  folk  with  which  to 
be  connected.  (Turn  to  next  page.) 


Your  Crystal  Set 

vclll  work  400  to  1000  mlle3  If  made  by  my  plana. 
No  tubes  or  batteries.  Copyrighted  plans  $1.00;  or 
furnished  FREE  with  complete  parts  for  building  set. 
including  special  coil  and  panel  correctly  drilled  for 
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funded. Satisfied  customers  everywhere.  Particulars 
free.  LEON  LAMBERT 

642  Kaufman  Bldg.  Wichita,  Kansas 


*      Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


69 


You  listeners-in  perhaps  do  not  realize 
the  effort  those  who  sing  and  play  for 
you  are  forced  to  make.  It  is  not  com- 
parable to  ordinary  "visual"  concertizing. 
Then,  the  artist  may  rest  between 
"numbers"  or  groups.  In  the  radio  studio 
he  cannot  do  so,  but  must  play  or  sing 
continuously  without  either  the  en- 
couragement of  applause  he  can  hear  or 
the  stimulus  of  an  audience  he  can  see. 

Such  co-operation  as  this  makes  the 
musical  director  of  any  station  glad  he  is 
permitted  to  take  part  in  the  program. 

Remember  this  the  next  time  you 
hear  something  you  particularly  like  and 
then  set  down  a  few  lines  of  appreciation 
for  the  artist,  send  it  to  the  station  which 
gave  you  the  pleasant  experience,  re- 
calling the  old  saying  that  "a  word  of 
praise  never  hurt  nobody,  nohow,  and 
it  might  do  a  pile  of  good." 

The  "old  saying"  is  probably  quoted 
wrong  but  you  get  the  idea. 

Signing  off  until — we  see  about  that 
program- — great  grief,  he's  sick  and 
can't  'come!!! — [Copyright,  1924,  by  the 
Chicago  Tribune  ] 


"Stone  Walls  Do  Not  a 
Prison  Make" 

(Continued  from  page  36.) 

Harry  is  but  29  years  old.  On  January 
16,  1925,  he  will  be  a  free  man,  able  to 
pursue  his  talent  to  its  rightful  place. 
Every  day  WOS  receives  hundreds  of 
letters  addressed  to  Snodgrass,  requesting 
favorite  numbers  and  thanking  him  for 
his  wonderful  playing.  These  letters 
come  from  other  lands  and  from  people 
in  all  walks^  of  life  in  America. 

Snodgrass  cannot  see  these  letters, 
but  he  is  told  about  them.  He  is  told 
about  the  scores  of  offers  from  broad- 
casting stations,  vaudeville  theaters  and 
concert  halls  that  come  in  every  mail. 
He  knows  that  going  to  prison  was  the 
best  thing  that  ever  happened  in  his  life 
and  that  he  can  pick  any  one  of  countless 
lucrative  offers  the  minute  he  leaves  the 
penitentiary. 

Stone  walls ,  do  not  a  prison  make. 
Rather,  they  spelled  a  Castle  of  the 
Future  for  Harry  Snodgrass,  "King  of 
the  Ivories,"  of  Station  WOS. 


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You'll  Find  the  Romance  of  the  Radio  World  in  RA- 
DIO AGE's  "What  the  Broadcasters  are  Doing"  Section 
every  month.  Read  about  the  "World's  Only  Radio 
Minstrel"  in  February  RADIO  AGE. 

*     Tested  and  Approved  by  RADIO  AGE     * 


70 


RADIO  AGE  for  January,   1924 


The  Magazine  of  the  Hour 


C  APEX^ERNIER  DIAL>^ 


It  Brings  'Em  In! 


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Prices  Smashed! 

Quality  Not  Sacrificed 


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"If  He  Can  Arrange  It" 

The  True  Story  of 

BANKS  KENNEDY 

in  February  RADIO  AGE 


A  Four -Tube  NEUTRO- REFLEX 
That  Gets  Results 


Set 


(Continued  from  page  13) 


three  quarters  of  an  inch  in  from  the  end 
as  was  done  on  the  large  tubes  (see  Figure 
No.  4).  The  end  of  the  No.  26  wire  will 
then  be  made  fast  by  passing  it  down 
through  one  hole,  up  through  the  other 
and  back  down  through  the  first  hole, 
leaving  about  two  inches  of  free  end  on 
the  inside  of  the  tube  for  connection. 

Fifteen  turns  of  the  wire  will  then  be 
wound  on  the  tubes  in  an  even  layer  in 
the  same  direction  as  the  secondary  coils 
and  two  more  small  holes  will  be  drilled 
directly  in  line  with  the  last  turn,  and 
in  line  with  the  first  two  holes  on  the 
other  end  of  the  tube  and  the  wire 
fastened  as  was  done  at  the  start,  leav- 
ing two  inches  of  free  end  on  the  inside 
of  the  tube  for  connection. 

The  coils  are  now  ready  to  be  assembled 
into  the  completed  radio  frequency 
transformers.  The  primary  coil  will  be 
inserted  into  the  secondary  coil  so  that 
holes  No.  1  and  No.  2  will  line  up.  One 
of  the  No.  4  brass  machine  screws  will 
be  passed  through  hole  No.  1,  a  brass 
nut  having  been  placed  between  the 
coils  as  shown  in  the  "left  end  elevation," 
figure  No.  3.  The  free  end  of  the  second- 
ary coil  opposite  hole  No.  1  will  then 
have  the  insulation  removed  and  will  be 
made  fast  under  the  second  nut  and  a 
third  nut  placed  on  the  screw,  forming 
the  terminal  No.  1  of  the  secondary  coil. 

The  same  procedure  should  be  followed 
with  the  screw  and  nuts  for  hole  No.  3 
except  that  the  free  end  of  the  primary 
coil  will  be  made  fast  under  the  head  of 
the  screw  on  the  inside  of  the  tubes, 
forming  primary  lead  No.  2. 

The  free  end  of  the  secondary  coil  on 
the  right  end  should  then  be  made  fast 
under  a  nut  on  the  screw  passed  through 
hole  No.  3  making  the  secondary  termi- 
nal No.  3.  The  free  end  of  the  primary 
coil  will  be  made  fast  under  the  head 
of  the  screw  passed  through  hole  No.  4, 
which  will  form  primary  terminal  No.  4. 

The  mounting  brackets  for  the  coils 
will  be  made  from  a  strip  of  brass  about 
three-eighths  of  an  inch  wide  and  about 
two  and  one-half  inches  long;  two  of  the 
brackets  will  be  bent  in  the  form  of  an 
"L"  as  shown  in  detail  No.  2,  figure  No.  4, 
and  one  to  form  a  step  as  shown  in 
detail  No.  1,  figure  No.  4.  The  upright 
leg  of  detail  No.  2  will  be  one  and  one- 
half  inches  long  and  have  a  hole  drilled 
to  pass  a  No.  4  brass  machine  screw,  one 
quarter  inch  down  from  the  top.  The 
foot  of  the  "L"  will  have  a  hole  drilled 
for  the   mounting   screw. 

The  foot  of  detail  No.  1  will  be  one- 
half  inch  long  and  have  the  hole  for 
the  mounting  screw  drilled.  The  rise 
will  be  one  inch  and  the  top  projection 
will  be  three-quarters  of  an  inch  long. 
The  hole  for  the  mounting  screw  will  then 
be  drilled  one-quarter  of  an  inch  in  from 
the  end  and  the  brackets  will  be  finished. 

The  next  step  will  be  to  mount  the 
brackets  to  the  coils.  The  bracket  known 
as  detail  No.  1  will  be  made  fast  to  the 
transformer  "R2"  by  a  No.  4  brass 
machine  screw  through  hole  No.  5  on  the 
*     Tested  and  Approved  by  RADIO  AGE     * 


right  end  of  the  tube;  one  detail  No.  2 
will  be  fastened  to  each  of  the  transform- 
ers "Rl"  and  "R3"  in  a  like  manner  and 
the  transformers  will  then  be  ready  to 
mount  into  the  set. 

'  I  "'HE  neutralizing  condensers  or  neu- 
-*■  trodons,  as  they  are  usually  called,  are 
small  variable  condensers  having  a 
capacity,  when  properly  adjusted,  equal 
to  that  of  the  tube  which  it  is  to  neutral- 
ize or  balance. 

The  one  described  herein  can  be  made 
at  a  cost  of  about  fifteen  cents.  Four 
pieces  of  thin  sheet  brass  or  aluminum 
about  fourteen  thousandths  of  an  inch 
in  thickness  and  one  and  one  half  inches 
square;  four  pieces  of  number  ten  bare 
copper  wire;  four  brass  binding  posts 
and  two  pieces  of  composition  one  and 
one-half  inches  wide  and  four  inches 
long  will  be  required,  as  well  as  four  small 
terminals,  as  shown  in  Figure  No.   5. 

The  construction  of  this  instrument 
is  so  simple  that  little  need  be  said  out- 
side of  what  is  shown  in  Figure  No.  5. 
Connecting  the  Set 

The  antenna  lead  will  be  made  fast  to 
the  binding  post  "A";  the  ground  will  be 
connected  to  the  binding  post  "G".  If  a 
loop  antenna  is  used,  the  leads  from  the 
loop  will  be  made  fast  to  the  binding 
posts  "A"  and  "G"  in  place  of  the  leads 
mentioned.  If  the  set  is  arranged  as 
shown  in  the  diagram  and  both  aerials 
arranged  for,  the  connections  will  be  made 
to  the  outside  antenna  and  to  the  ground 
as  covered  above.  The  loop  terminals 
are  made  fast  to  a  phone  plug.  This 
phone  plug  will  be  inserted  into  the  cutoff 
jack  "X"  when  it  is  desired  to  use  the 
loop.  The  other  connections  can  remain 
in  place  as  the  cutoff  jack  automatically 
cuts  off  the  radio  frequency  transformer 
Rl  and  connects  the  loop  to  the  set. 

The  terminals  of  the  "A"  or  filament 
battery  will  be  connected  to  the  binding 
post  "Al"  and  "A2",  the  positive  lead 
or  lead  "  +  "  will  go  to  the  post  marked 
"A2"  and  the  negative  lead  or  lead 
marked  " — "  to  the  post  marked  "Al." 

The  "B"  or  plate  battery  will  be  con- 
nected to  the  binding  posts  marked  "B" 
"Bl"  and  "B2".  The  negative  side  of 
the  battery  will  be  connected  to  the  post 
marked  "B2",  a  tap  will  be  taken  at 
22  1-2  volts  and  will  be  connected  to 
post  marked  "B";  the  positive  terminal 
of  the  battery  will  then  be  connected 
to  the  post  marked  "Bl".  The  conect 
"B"  or  plate  battery  for  this  set  will  be 
from  90  to  120  volts. 

When  the  batteries  have  all  been  con- 
nected, test  the  two  springs  in  the  tube 
sockets  to  see  that  the  "A"  battery  is 
not  shorted  with  the  "B"  battery.  This 
will  be  done  by  temporarily  removing 
one  of  the  leads  to  terminals  "Al"  or 
"A2"  and  shorting  the  springs  in  the 
tube  socket  marked  "F — "  and  "F  +  ", 
(these  designations  will  appear  on  the 
sockets).  If  no  spark  is  made,  the 
battery  lead  will  be  then  made  fast 
again,    the    tube    control    rheostat    "D" 


RADIO  AGE  for  January,   192; 


turned  to  its  "off"  position,  and  the 
tubes  placed  in  their  sockets.  The  phones 
or  loud  speaker  will  then  be  connect :d 
to  a  phone  plug  and  the  plug  inserted 
into  the  phone  jack  "Y".  The  rheostat 
"D"  can  then  be  turned  on  until  the 
filaments  of  the  tubes  are  caused  to  glow 
white. 

Tuning  the  Set 

The  dials  of  the  condensers  will  then 
be  turned  to  about  thirty-five  and  all 
three  of  them,  "CD1",  "CD2",  and 
"CD3"  rotated  back  and  forth  until  a 
station  is  heard.  This  signal  should  be 
brought  up  to  its  best  volume.  Then 
remove  the  tube  in  socket  "Ml",  place 
a  piece  of  paper  over  the  filament  spring 
from  contact  "F — "  and  place  the  tube 
back  into  its  socket.  The  filament  of 
this  tube  will  not  glow  now  as  the  "A" 
or  filament  battery  has  been  disconnected 
from  the  contact  on  the  tube.  The 
neutralizing  condenser  will  then  be 
adjusted  until  no  signal  is  heard  in  the 
phones  or  the  loud  speaker.  When  this  is 
accomplished,  the  thumb  screw  on  the 
neutralizing  condenser  "N"  will  be 
tightened  and  the  paper  removed  from 
the  socket.  The  tube  will  be  replaced 
and  condenser  "N"  is  properly  neutral- 
ized. The  same  procedure  is  taken  with 
the  socket  "M2"  and  the  tube  in  this 
stage  and  the  neutralizing  condenser 
"Nl",  when  no  signal  is  heard  the  con- 
denser will  be  set  and  the  tube  put  into 
action,  as  was  done  to  the  first  tube. 
The  set  will  then  be  properly  neutralized 
and  will   not   oscillate. 

To  tune  in  a  station,  the  dials  should 
all  be  turned  to  the  same  number  and 
moved  around  in  this  location  until  a 
signal  is  heard,  strengthening  the  signal 
by  adjusting  the  filament  control  rheostat 
"D"  and  moving  the  dials  "CD1", 
"CD2"  and  "CD3"  until  the  desired 
volume   is  obtained. 


The  Magazine  of  the  Hour 


71 


^2£r«i 


MICA  CONDENSER 

Patent  Pending 

insure  high  efficiency  and  the 
Build-Up  feature  enables 
the  operator  to  obtain  any- 
definite  capacity  from  .0005 
to  .006  by  simply  adding 
extra  plates  of  copper  and 
mica  to  the   Build-Up  base. 

Each  alternate  copper  and  mica  plate  has  a 
capacity  of  approximately  .0002  Mfd. 

Build-Up  Mica  Condensers  of  the  following 
capacities,  each  assembled  complete  in  carton, 
at  the  following  prices: 

.00025  Mfd List  price  50c 

.0005        "     ••       »         50c 

.001  "    "      "         55c 

.002  "     «       "  60c 

.0025  "   "       "  65c 

.005  V   ..  «       »  70c 

.006  "   ....  "       »  75c 

Extra  envelope  containing  20  copper  and 
mica  plates,  or  sufficient  to  build  up  a  con- 
denser from  .00025  to  .006,  list  price  25c. 

Table  showing  required  number  of  plates 
needed  for  any  capacity  is  furnished  with 
each  condenser. 

Ask  your  dealer — or  order  direct 

CHAS.  SCHINDLER 

1404  W.  Delaware  Ave.,  Toledo,  Ohio 


That      # 

Silver  Super 

in  Delhi,  N.Y., 

is  rolling  up  some  record 


LABORATORY  MODEL 


LAST  MONTH   Mr.  George   C.    Cannon   wrote. ... 

Silver    Super    adjusted fine   test   run all 

reasonable    stations    received    on    loud    speaker.... 

Brought   in  KGO  with  Loud   Speaker  Volume    on    an 
18"  Loop  four  consecutive  nights 


Get 

This  Book! 


"The  Portable 
Super-Heterodyne" 

By  McMurdo  Silver 
Assoc.  I.  R.  E. 

It  is  a  complete  record 
of  Mr.  Silver's  experience 
with  hundreds  of  Super- 
heterodynes.       You  will 

Dope  that  was  never  be- 
fore available.  Its  detail 
drawings  and  photo- 
graphs enable  you  to 
build  either  the  Portable 
or  Laboratory  Model 
S  u  per-  heterodyne,  on 
your  kitchen  table  with 
a  pair  of  Pliers,  a  Screw 
Driver  and  a  Soldering 
Iron.     Priee  per  copy 


"K  T/^\"\"\  7"  Mr.      Cannon     reports 

r\  1  1  W  have  received  KGO  (Oakland) 
X  ^  ^^  T7  on  Silver  Super  in  Delhi,  N.  Y., 
every   night   they    have    transmitted    for   the 

past  two    weeks Wonderful  reception 

loud  speaker  volume  on  18"  Loop -. 

SILVER  SUPERS 

all    over   the   country   are   rolling    up   similar 

records   in   routine  performance records 

not  matched  by  any  other  receiver.  Silver 
Supers    do   out-perform    the    best    of   them — 

regardless    of    make    and    price they    are 

7-Tube  Wonders,  and  you  can  build  them  your- 
self with  a  pliers,  screw  driver  and  a  soldering 
iron. 

Parts 

Portable  Model '. $57.65 

Laboratory  Model 63.60 

Mail  your  order  today 
Shipments  prepaid  East  of  the  Rockies 


SILVER  SUPER  SPECIALS 

Bring  Your  Old  Super  Up-To-Date 

No.  101— Oscillctor  Coupler,  150-600  meters.  .  .$  2.50 

No.  201 — 30  KC  Tuned  Output  Transformer. . .  3.50 

No.  301— .0005  Low  Loss  Condenser 4.50 

No.  401—50  KC  RF  Transformer  Unit 14.00 

No.  501— 5-Gang  199  Socket 3.00 

No.  601 — Collapsible  Center-tapped  Loop 6.50 

Circulars  Upon  Request 


50c 


Dealers — Write     for    our    attractive     merchandising    plan. 


EASTERN  DISTRIBUTOR 
Twentieth  Century  Radio  Corp.,  102  Flatbush  Avenue,  Brooklyu,  N.  Y. 

Silver-MarshalLinc. 


105  S.  Wabash  Ave., 


Dept.  C, 


Chicago 


RADIO  AGE  SUBSCRIPTION  BLANK 

Radio  Age,  Inc., 

500  North  Dearborn  Street, 
Chicago 

Gentlemen:    Please  enter  my  subscription  for  RADIO  AGE,  ths  Magazine  ol  the  Hour,  for  od«  year,  beginning 
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RADIO  AGE  for  January,   1925 


The  Mavazine  of  the  Hour 


$ 


RADIO 


PAYS  BMGI 

IARNs3OO0fc*9OO0aYear 

Enter  fast  growing  radio  field,  thousands  of  big  pay 
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Regeneration  Plus  Modulation 

By  Hogart  S.  Sweet 


REGENERATION  plus  modulation 
is  the  keystone  of  a  new  model 
-  ultradyne  receiver  designed  by 
Robert  E.  Lacault,  formerly  Radio 
Research  Engineer  with  the  French  Signal 
Corps.  This  combination  is  going  to 
prove  as  valuable  to  the  level  minded 
radio  fan  as  four  wheel  brakes  and  balloon 
tires  have  to  the  level  minded   autoist. 


around  with  one  or  a  couple  of  rheostats 
every  time  you  shift.  If  you  are  using 
both  stages  of  audio  and  wish  to  shift 
to  the  detector,  out  comes  the  plug  with 
your  own  hands  and  out  go  the  two 
audio  frequency  amplifier  tubes.  Like- 
wise, on  one  or  hoth  go  when  the  plug 
is  inserted  in  one  or  the  other  jack. 
All  binding  posts  have  been  moved  to 


A  horizontal  rear  view  of  the  new  Ultradyne  L-2  as  designed  by  Mr.  Lecault.     Note  the  neat  arrange- 
ment of  apparatus. 


There  is  a  strong  comparison  here;  for 
both  the  autoist  and  radio  fan  seek  the 
same  things,  namely:  smooth  operation 
and  reliable  and  instant  control. 

Regeneration  plus  modulation!  You 
can  theorize  until  you  are  blue  in  the 
face,  you  can  draw  conclusions  on  such  a 
combination  from  experience  with  regen- 
eration in  conjunction  with  the  usual 
form  of  super-heterodyne,  but  until  you 
experience  the  performance  of  the  new 
ultradyne,  you  don't  know  the  half  of  it! 

But  think  it  over  from  the  theoretical 
standpoint  anyway;  we  know  the  advan- 
tages of  the  super-heterodyne;  maximum 
amplification  for  each  radio  frequency 
stage  for  one  thing  and  ease  of  control 
for  another.  Add  to  this  the  modulation 
system  and  we  make  the  first  detector 
or  frequency  changer  perform  a  real  serv- 
ice by  modulating  the  oscillations  pro- 
duced by  the  oscillator  tube  and  thus 
enormously  boost  the  amplitude  of  the 


the  rear,  where  they  rightfully  belong,, 
for  there  should  be  no  wires  in  front  or' 
on  the  side  of  the  receiver,  but  behind,- 
where  they  are  out  of  sight  and  out  of 
the  way.  The  two  variable  condensers,, 
of  the  low  loss  type,  are  both  of  the  same' 
capacity,  whereas  before  one  was  twice 
the  capacity  of  the  other.  Making  them 
both  of  a  capacity  of  .0005  M.  F.  provides 
a  more  even  adjustment  than  was  possible 
with  the  original  type  of  ultradyne. 

Naturally,  the  old  type  single  layer 
cylindrical  coils  have  been  replaced  by 
coils  of  the  low  loss  type.  These  are  the 
basket  weave  form  and  are  more  compact 
than  the  single  layer  type. 

It  will  be  noted  from  the  photo  that 
there  is  a  radical  change  in  the  position 
of  the  controls.  Both  the  tuning  dials, 
are  situated  in  the  center  of  the  panel , 
really  the  most  convenient  positions  for 
them — -right  where  your  hands  normally 
rest.     The  regeneration  control  a;ftd  the 


A  view  of  the  ultradyne  receiver  showing  the  layout  of  the  parts, 
builders  of  this  hookup. 


Unusual  results  are  reported  by 


incoming  signal  before  it  ever  reaches  the 
long  wave  radio  frequency  amplifiers. 
Now,  suppose  we  add  the  most  sensitive 
and  efficient  system  of  amplification 
known  to  the  radio  art;  regeneration. 
To  be  more  exact,  suppose  we  include 
regeneration  in  the  modulator  tube  cir- 
cuit.    What  is  the  result? 

The  Specifications 

BUT  listen  to  the  specifications  of  Mr. 
Lacault's  Model  L-2  Ultradyne,  be- 
fore we  cover  the  constructional  details: 
There  are  no  rheostats!  The  filaments 
of  all  the  vacuum  tubes  are  controlled 
by  automatic  filament  regulating  devices. 
Filament  control  jacks  are  employed  for 
the  two  stages  of  audio  frequency  amplifi- 
cation so  that  it  is  not  necessary  to  play 
*     Tested  and  Approved  by  RADIO  AGE     ¥ 


potentiometer  control  are  out  to  either 
side,  being  the  less  important  adjusting 
mediums.  i 

The  panel  layout  is  shown  in  the  photo. 
The  loop  aerial  jack  is  at  the  extreme  left 
followed  by  the  regeneration  control 
knob,  the  tuner  dial,  the  oscillator  dial 
and  the  potentiometer  control.  The; 
three  phone  jacks  and  the  "A"  battery 
switch  are  lined  up  on  the  extreme  right 
of  the  panel. 

A  view  of  the  layout  from  the  rear  of 
the  panel  is  also  shown.  From  left  to 
right  are:  the  phone  jacks  and  "A" 
battery  switch,  the  potentiometer,  the  23 
plate  oscillator  condenser,  the  23  plate 
tuning  condenser,  the  regeneration  coup- 
ler and  its  copper  shield,  and  the  loop 
aerial  jack.  (Turn  to  next  page) 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


73 


Another  photo  shows  a  view  of  the 
instruments  mounted  on  the  baseboard. 
The  devices  similar  in  appearance  to  grid 
leaks  are  the  automatic  filament  regula- 
tors. The  oscillator  coupler  is  seen  just 
to  the  right  of  the  second  rear  tube 
socket.  The  tuning  coil  is  situated  to  the 
extreme  right  of  the  baseboard.  The 
ultraformers  are  seen  lined  along  the 
front  portion  of  the  baseboard,  in  the 
photo,  though  this  is  actually  the  rear. 
The  "A,"  "B"  and  "C"  battery  binding 
posts  are  all  mounted  on  a  single  strip 
of  bakelite  which  is  supported  by  two 
brass  columns,  and  are  at  the  extreme 
left  of  the  baseboard,  in  the  photo.  The 
aerial  and  ground  binding  posts  are 
mounted  in  the  same  manner  and  are  seen 
to  the  extreme  right. 

The  Parts  Required 

I — 7    x  30    cabinet  with  baseboard. 

1 — 7*  2  30"  Dane). 

2—  .0005  M.  F.  low  loss  variable  condensers. 

2 — -vecnier  knobs  and  dials. 

1 — row  loss  tuning  coil. 

1 — low  loss  oscillator  coil. 

I — ultraformer — type  A. 

3 — ultraformers — type  B. 

1— low  loss  180°  coupler  with  shield. 

1 — dial  for  coupler. 

8 — vacuum  tube  sockets. 

1 — 300  to  400  ohm  potentiometer. 

8 — amperites — type  A. 

2 — double  circuit  jacks. 

1 — double  circuit  filament  control  iack. 

1 — sinKle  circuit  filament  control  Jack. 

1 — "A"  battery  switch. 

2 — audio  frequency  transformers. 

1 — variable  grid  leak. 

7 — binding  posts. 

2 — bakelite  binding  post  mounting  strips. 

1 — .0005  M.  F.  condenser  with  grid  leak  mounting. 

4 — .00025  M.  F.  filed  condensers. 

2— .001  M.  F.  filed  condensers. 

1— .005  M.  F.  filed  condenser. 

No.  14  tinned  copper  bus  bar  wire. 

Assortment  of  screws  and  outs. 

The  first  job  to  be  done  is  the  panel 
drilling  and  the  mounting  of  the  phone 
jacks,  "A"  battery  switch,  the  two  23- 
plate  variable  condensers,  the  potentio- 
meter and  the  coupler  and  shield. Lay  out 
the  baseboard  next,  placing  each  instru- 
ment in  its  proper  position  as  shown  in 
the  photo.  Wire  the  instruments 
mounted  on  the  panel  first,  then  the 
instruments  on  the  baseboard.  Be  sure 
to  solder  all  connections  and  take  your 
time  about  it  to  insure  a  good  job.  Be 
sparing  with  the  soldering  flux  and  use  a 
hot  iron.  After  both  the  panel  and  base- 
board instruments  have  been  wired, 
attach  the  baseboard  to  the  panel  and 
complete  the  wiring  between  the  instru- 
ments on  each. 

Be  sure  to  check  all  the  connections 
when  you  have  completed  the  wiring,  and 
as  a  final  check  up,  test  each  soldered 
joint  with  a  battery  and  headphones  to 
insure   perfect   electrical   contact. 

After  all  instruments  and  connections 
have  been  tested,  insert  the  tubes  in  the 
sockets,  connect  up  the  "A,"  "B"  and 
"C"  batteries  to  the  proper  binding  posts, 
plug  in  the  loop  aerial  or  attach  the 
aerial  and  ground,  and  with  the  phones 
or  loud  speaker  plugged  in,  pull  the  fila- 
ment switch. 

Tuning  the  Set 

T^HE  following  is  the  correct  procedure 
-1-  for  tuning  the  set:  turn  the  oscillator 
dial  one  degree  at  a  time  and  for  each 
setting  of  this  dial  turn  the  tuning  dial 
slowly  through  its  whole  range.  If 
nothing  is  heard  at  any  setting,  move 
the  oscillator  dial  one  more  degree  and 
repeat  the  process  with  the  tuning  dial. 
At  some  point,  one  should  hear  a  station, 
and  it  will  be  noticed  that  a  slight  hissing 


noise  is  heard  when  the  station  is  trans- 
mitting, but  no  one  speaking  or  singing 
into  the  microphone.  -This  slight  hissing 
noise  indicates  the  presence  of  a  carrier 
wave  and  will  help  materially  in  tuning 
in  the  various  broadcast  stations. 

AH  this  tuning  should  be  done  with  the 
potentiometer  adjusted  to  a  point  where 
no  whistles  are  heard.  If  whistling 
noises  are  present,  the  potentiometer 
should  be  turned  towards  the  positive 
side  until  the  whistling  stops,  at  which 
point  the  amplifier  operates  at  its  maxi- 
mum sensitiveness.  When  tuning  in 
distant  stations,  it  may  be  necessary  to 
readjust  the  potentiometer  slightly.  This 
should  be  done  only  after  the  station  is 
heard  faintly,  but  clearly  enough  to 
increase  the  amplification. 

When  tuning  in  very  weak  signals,  the 
feed-back  or  regenerative  coupler  should 
be  turned  slowly  until  a  point  is  reached 
where  a  whistle  is  heard,  then  moved 
back  just  below  this  point.  A  slight 
readjustment  of  the  two  condensers  will 
then  bring  the  signal  to  maximum  audi- 
bility. When  tuning  in  another  station, 
turn  the  feed-back  coupler  to  zero  (coils 
at  right  angle)  and  tune  first  with  the 
two  condensers,  as  explained  above,  then 
adjust  the  coupler  when  the  station  is 
tuned  in.  \ 

It  should  be  pointed  out  that  the 
regeneration  feature  incorporated  in  the 
new  ultradyne  is  a  form  of  radio  fre- 
quency amplification  and  consequently 
plays  its  most  important  part  when  you 
are  receiving  a  long  distance  station.  Its 
use  does  not  increase  the  volume  of  the 
signals  received  from  local  stations  to  any 
appreciable  extent,  this  not  being  the 
object.  Greater  volume  can  always  be 
obtained  by  the  addition  of  audio  fre- 
quency amplification ;  but  it  does  increase 
the  volume  of  stations  at  a  distance  for 
the  reason  that  the  weak  signals  are 
boosted  in  amplitude  before  they  pass 
through  the  long  wave  radio  frequency 
amplifier.  Since  the  object  of  the  regen- 
eration feature  is  to  make  the  Ultradyne 
more  sensitive  to  weak  signals,  it  should 
be  evident  that  it  will  not  only  increase 
the  volume  of  signals  from  distant  sta- 
tions and  insure  consistent  reception,  but 
will  also  pick  up  the  signals  from  stations 
that  could  not  be  heard  on  an  Ultradyne 
withoat  regeneration. 

With  the  addition  of  regeneration,  it 
will  be  found  that  the  second  stage  of 
audio  frequency  amplification  is  of  real 
use  only  when  receiving  from  very  distant 
stations.  All  the  volume  -desired  is  had 
with  one  stage  of  audio  frequency  ampli- 
fication when  receiving  local  or  semi-local 
stations.  The  second  stage  of  audio 
frequency  amplification,  however,  is 
quite  desirable  for  long  distance  work 
and  may  be  likened  to  a  high  powered 
car  in  which,  under  normal  conditions,  the 
surplus  power  is  not  used,  but  is  there  for 
use  in  case  of  emergency. 


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RADIO  AGE   THE   AIR! 
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AGE'S  broadcast  programs  from 

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74 


RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA 

KDPM 

KDPT 

KDYL 

KDYM 

KDYQ 

KDZB 

KDZE 

KDZI 

KDZR 

KFAD 

KFAE 

KFAF 

KFAJ 

KFAR 

KFAU 

KFAW 

KFAY 

KFBB 

KFBC 

KFBE 

KFBC 

KFBK 

KFBL 

KFBS 

KFBU 

KFCB 

KFCF 

KFCL 

KFCP 

KFCV 

KFCZ 

KFDD 

KFDH 

KFDJ 

KFDX 

KFDY 

KFDZ 

KFEC 

KFEK 

KFEL 

KFEQ 

KFER 

KFEY 

KFFB 

KFFE 

KFFP 

KFFR 

KFFV 

KFFY 

KFCB 

KFCC 

KFGD 

KFCH 

KFCL 

KFGQ 

KFGX 

KFGZ 

KFHA 

KFHH 

KFHJ 

KFHR 

KFI 

KFIF 

KFIO 

KFIQ 

KFIU 

KFIX 

KFIZ 

KFJB 

KFJC 

KFJF 

KFJI 

KFJK 

KFJL 

KFJM 

KFJQ 

KFJR 

KFJX 

KFJY 

KFJZ 

KFKA 

KFKB 

KFKV 

KFKQ 

KFKX 

KFKZ 

KFLA 

KFLB 

KFLD 

KFLE 

KFLQ 

KFLR 

KFLU 

KFLV 

KFLW 

KFLX 

KFLZ 

KFMB 

KFMQ 

KFMR 

KFMT 

KFMW 

KFMX 

KFNF 

KFNG 

KFNL 

KFNV 

KFNY 

KFNZ 

KFOA 

KFOC 

KFOD 

KFOJ 

KFOL 

KFON 

KFOO 

KFOP 

KFOR 

KFOT 

KFOU 

KFOX 

KFOY 

KFOZ 

KFPB 

KFPG 

KFPH 

KFPL 

KFPM 

KFPN 

KFPO 

KFPP 

KFPR 

KFPT 

k-FPV 

KFPW 

KFPX 

KFPY 


Westinghou-e  Electric  &   Mfg.  Co East  Pittsburgh  326 

Westinghot  se  Electric  &  Mfg.  Co Cleveland,  Ohio  270 

Southern  Electrical  Co San  Diego.  Calif.  244 

Newhouse  Hotel Salt  Lake  City.  Utah  360 

Savoy  Theatre San  Diego,  Calif.  280 

Oregon  Institute  of  Technology Portland,  Oreg.  360 

Frank  E.  Siefert Bakersfield.  Calif.  240 

Rhodes  Department  Store Seattle.  Wash.  270 

Electric  Supply  Co Wenatchee.  Wash.  360 

Bellinghara  Publishing  Co Bellingham,  Wash.  261 

McArthur  Bros.  Mercantile  Co Phoenix.  Ariz.  360 

State  College  of  Washington Pullman,  Wash.  330 

Western    Radio  Corporation Denver.   Colo.  278 

University  of   Colorado Boulder,   Colo.  360 

Studio  Lighting  Service  Co.  (O.  K.  Olsen) Hollywood.  Calif.  280 

Boise  High   School Boise,  Idaho  270 

The  Radio  Den  (W.  B.  Ashford) Santa  Ana.  Calif.  280 

Virgin's  Radio  Ser.dce Medford,  Ore.  283 

F.  A.  Buttrey  &  Co Havre,  Mont.  360 

W.  K.  Azbill San  Diego.  Calif.  278 

Reuben  H.  Horn San  Luis  Obispo,  Calif.  242 

First  Presbyterian  Church Tacoma,   Wash.  360 

Kimball-Upson  Co Sacramento,  Calif.  283 

Leese  Bros Everett,  Wash.  224 

Trinidad  Gas  &  Electric  Supply  Co.  and  the  Chronicle  News  Trinidad,  Colo.  280 

The  Cathedral Laramie.  Wyo.  283 

Nielson  Radio  Supply  Co Phoenix,  Ariz.  238 

Frank  A.  Moore Walla  Walla.  Wash.  360 

Leslie  E.  Rice Los  Angeles.  Cal.  236 

Ralph    W.    Flygare Ogden.    Utah  360 

Fred    Mahaffey,   Jr Houston,   Texas  360 

Omaha  Central  High  School Omaha,  Nebr.  258 

St.  Michaels  Cathedral Boise,  Idaho  252 

University  of  Arizona Tuscon,  Ariz.  368 

Oregon  Agricultural  College Corvallis,  Oreg.  360 

First  Baptist  Church Shreveport.  La.  360 

South  Dakota  State  College Brookings,  8.  Dak.  360 

Harry  O.  Iverson Minneapolis.  Minn.  231 

Meier  &  Frank  Co Portland,  Oreg.  248 

Augsbury    Seminary Minneapolis,    Minn.  261 

Winner  Radio  Corp Denver,  Colo.  254 

J.  L.  Scroggin Oak,  Nebr.  268 

Auto  Electric  Service  Co Fort  Dodge.  Iowa  231 

Bunker  Hill  A  Sullivan  Mining  and  Concentrating  Co Kellogg.  Idaho  360 

Jenkins  Furniture  Co Boise,  Idaho  240 

E.   H.Smith Hillsboro,  Oreg.  229 

First  Baptist  Church Moberly,  Mo.  266 

Nevada  State  Journal  (Jim  Kirk) Sparks,  Nev.  226 

Graceland   College Lamoni,   Iowa  280 

Pinrus     &     Mnrphey     Music     House Alexandria.     La.  275 

Heidbreder    Radio   Supply   Co Utica.   Neb.  224 

Louisiana  State  University Baton  Rouge,  La.  254 

Chickaslia   Radio  &  Electric  Co Chickasha.  Okla.  248 

Leland  Stanford  University Stanford  University.  Calif.  273 

Suell  &  Irby Arlington,  Oreg.  234 

Crary  Hardware  Co Boone.  Iowa  226 

First  Presbyterian   Church Orange,   Tex.  250 

Emmanuel  Missionary  College Berrien  Springs.  Mich.  286 

Western  State  College  of  Colorado Gunnison.  Colo.  252 

Ambrose  A.  McCue Neah  Bay.  Wash.  261 

Fallon  &  Co Santa  Barbara.  Calif.  360 

Star  Electric  &  Radio  Co Seattle.  Wash.  283 

E.  C.  Anthony.   Inc Los   Angeles,  Calif.  469 

Benson   Polytechnic   Institute Portland.   Oregon  360 

North  Central  High  School Spokane.  Wash.  252 

First   Methodist   Church Yakima.   Wash.  242 

Alaska  Electric  Light  A  Power  Co Juneau.  Alaska  226 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints. Independence,  Mo.  240 

Daily  Commonwealth  and  Oscar  A.  Huelsman Fon  Du  Lac,  Wis.  273 

Marshall  Electrical  Co Marshalltown,  Iowa  248 

Seattle   Post   Intelligencer Seattle,    Wash.  270 

National  Radio  Manufacturing  Co - Oklahoma  City,  Okla.  252 

Liberty  Theatre  (E.  E.  Marsh) Astoria,  Ores.  252 

Delano   Radio   and   Electric   Co Bristow,   Okla.  233 

Hardsacg  Manufacturing  Co Otturawa,  Iowa  242 

University   of   North    Dakota Grand   Forks,    N.    Dak.  280 

Valley  Radio.  Div.  of  Elec.  Constr.  Co Grand  Forks.  N.  D.  280 

Ashley  C.  Dixon  &  Son Stevensville.   Mont,   (near)  258 

Iowa  State  Teacher's  College '. Cedar  Falls,  Iowa  280 

Tunwall   Radio  Co i Fort   Dodge,   Iowa  246 

Texas  National  Guard.  One  hundred  and  twelfth  Cavalry. Fort  Worth  Texas  254 

Colorado  State  Teachers  College Greeley,  Colo.  273 

Brinkley-Jones   Hospital   Association Milford,    Kans.  286 

F.  F.  Gray Butte,  Mont.  283 

Conway  Radio  Laboratories  (Ben  II.  Woodruff) Conway.  Ark.  250 

Westinghouse  Electric  &  Manufacturing  Co Hastings.  Nebr.  341 

Nassour  Bros.    Radio   Co Colorado   Springs,   Colo.  234 

Abner  R.  Willson Butte.   Mont.  283 

Signal  Electric   Manufacturing   Co Menominee.   Mich.  248 

Paul  E.  Greenlaw Franklinton.   La.  234 

National   Educational   Service Denver,   Colo.  268 

Bizzell  Radio  Shop Little  Hock.  Ark.  261 

University  of  New  Mexico Albuquerque,   New  Mexico  254 

Rio  Grande  Radio  Supply  House San  Benito,  Texas  236 

Rev.  A.  T.  Frykman Rockford.  III.  229 

Missoula   Electric   Supply   Co Missoula,    Mont.  234 

George  Roy  Clough Galveston.  Tex.  240 

Atlantic   Automobile   Co Atlantic.    la.  273 

Christian  Churches Little  Rock,  Ark.  254 

University  of  Arkansas Fayetteville,  Ark.  263 

Morningside  College Sioux  City.  Iowa  261 

Dr.  George  W.  Young Minneapolis,  Minn.  231 

M.   G.   Sateren Houghton.    Mich.  266 

Csrleton  College Xorthfield.  Minn.  283 

Henry  Field  Seed  Co Shenandoah.  Iowa  266 

Wooten's   Radio  Shop Coldwater,   Miss.  254 

Radio  Broadcast  Ass'n Paso  Rol.les.  Calif.  240 

L.  A.  Drake  Battery  and  Radio  Supply  Shop Santa  Rosa.  Calif.  234 

Montana   Phon.  .graph    Co Helena.   Montana  261 

Royal   Radio  Company Burlingair.e.  Calif.  231 

Rhodes  Department  Store Seattle  .Wash.  455 

First  Christian   Church Whittier.   Calif.  236 

Radio  Shop Wallace .  Idaho  224 

Moberly  High  School  Radio  Club Moberly.  Missouri  246 

Leslie  M.   Schafbush Marengo,   Iowa  234 

Echophone  Radio  Shop Long   Beach.  Calif.  234 

Latter  Day  Saints  University. .- Salt  Lake  City.  Utah  261 

Rohrer       Elec.       Co Marahneld       Ore.  240 

David  City  Tire  &  Electric  Co David  City.  Nebraska  226 

College  Hill  Radio   Club Wichita.   Kansas  231 

Homme!   Mfg.  Co Richmond.  Calif.  254 

Board  of  Education,  Technical  High  School Omaha.   Nebraska  248 

Beacon  Radio  Service St.   Paol.  Minn.  226 

Leon  Hudson  Real  Estate  Co Fort  Smith,  Ark.  233 

Edwin    J.    Brown      Seattle,    Wash.  224 

Garretson  and   Dennis Los   Angeles.  Calif.  238 

Harold  Chas.  Mailander Salt  Lake  City.   Utah  242 

C.   C.   Baxter Dublin,   Texas  242 

The  New  Furniture  Co Greenville,  Texas  242 

Missouri  National  Guard Jefferson  City.  Mo.  242 

Colorado  National  Guard Denver,  Colo.  231 

G.  &  G.  Radio  &  Electric  Shop Olympia,  Washington  236 

Los  Angeles  Co.  F'orestry  Dept Los  Angeles,  Calif.  231 

Cape     &    Johnson Salt     Lake     City,  Utah  268 

Heintz  &   Kohlmoos,  Inc San  FranciBco.  Calif.  236 

St.  Johns  M.  E.  Church Cnrterville,  Mo.  268 

First    Presbyterian    Church Pine    Bluff,    Ark.  242 

Symons  Investment  Co Spokane.  Wash.  283 


KFQA 

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The  Principia St.  LouiB,  Mo.  261 

The  Searchlight  Publishing  Co Fort  Worth,  Tex.  254 

Kidd  Brothers  Radio  Shop Taft.  Calif.  227 

Chovin  Supply  Co Anchorage,  Alaska  280 

Dickenson-Henry  Radio  Laboratories Colorado  Springs,  Colo.  224 

D.  A.  Boult Minneapolis,  Minn.  224 

Southern  Calif.  Radio  Ass'n Los  Angeles.  Calif.  226 

Radio    Service    Co Burlingame,  Calif.  231 

The  Thos.  H.  Ince  Corp Culver  City,  Calif.  234 

Harbour-Longmire  Company Oklahoma  City.  Okla.  2*6 

Democrat  Leader. Fayette,  Mo.  236 

Oklahoma  Free  State  Fair  Assn Muskogee.  Okla.  252 

Texas      Highway      Bulletin Austin,      Tex.  268 

Third     Baptist     Church Pnrtland.     Ore.  283 

Meier   Radio   Shop Russell,    Kans.  261 

G.   S.    Carson.    Jr Iowa    City.    la.  224 

Walter  LaFayette  Ellis Oklahoma    City,    Okla.  250 

Texas   National  Guard Denison.   Texas  252 

W.  Riker Holy  City,  Calif.  234 

Omaha  Grain  Exchange    (Portable) Omaha,  Nebr.  231 

C.   F.   Knierim North   Bend.   Wash.  248 

Alfred    M.    Hubbard Seattle.   Wash.  233 

Farmers      State     Bank Belden.      Neb.  273 

Taft    Radio    Co : Hollywood,    Calif.  240 

The  Reynolds  Radio  Co.  Inc.  Portable  Station Denver,    Col.  224 

Guy  Simmons,  Jr.. Conway.  Ark.  250 

United  Churched  of  Olympia Olympia.  Wash. 220 

Angelus  Temple Los  Angeles,  Calif.  278 

The  Van  Blaricon  Co Helena. Mont.  261 

Tacoma  Daily   Ledger Tacoma,  Wash.  252 

Hallock  &  Watson   Rjuiio  Service Portland,   Oreg.  360 

General   Electric    Co ~ Oakland,    Calif.  312 

Marion  A.  Mulrony Honolulu.  Hawaii.  Waikiki  Beach  360 

Portland  Morning  Oregonian Portland,   Oreg.  492 

St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy,  Wash.  258 

Times-Mirror    Co Los    Angeles.    Calif.  39S 

Louis    Wasmer Seattle,    Wash.  360 

C.  O.  Gould Stockton,    Calif.  273 

Northwest  Radio  Service  Co Seattle.  Wash.  283 

Bible  Institute  of  Los  Angeles Los  Angeles,  Calif.  360 

Warner  Brothers   Radio  Supplies  Co Oakland,   Calif.  360 

Tribune  Publishing  Co Oakland,  Calif.  509 

Reynolds  Radio  Co Denver,   Colo.  283 

San  Joaquin  Light  &  Power  Corp Fresno,  Calif.  248 

Love  Electric  Co Tacoma,  Wash.  360 

Walter  Hemrich Kukah  Bay,  Alaska  263 

Los  Angeles  Evening  Express Los  Angeles,  Calif.  337 

New  Mexico  College  of  Agriculture  &  Mechanic  Arts.  .State  College.  N.  Mex.  360 

Detroit  Police  Department Detroit,  Mich.  286 

Hale  Bros San  Francisco.  Calif.  423 

Apple  City  Radio  Club Hood  River,  Oreg.  360 

Doubleday-Hill   Electric   Co Pittsburgh .  Pa.  270 

Charles  D.  Herrold San  Jose,  Calif.  360 

V  C  Battery  &  Electric  Co Berkeley.  Calif.  275 

Post  Dispatch   (Pulitzer  Pub.  Co.) St.  Louis,  Mo.  S46 

First   Presbyterian   Church Seattle,   Wash.  360 

Examiner  Printing  Co San   Francisco,  Calif.  360 

Portable  Wireless  Telephone  Co Stockton,  Calif.  360 

Los   Angeles    Examiner Los   Angeles,    Calif.  360 

Electric    Shop Honolulu,    Hawaii  270 

Westinghouse  Electric  &  Mfg.  Co Chicago.  111.  536 

Preston    D.    Allen Oakland,    Calif.  360 

Valdemar    Jensen New    Orleans,    La.  268 

Tulane  University New  Orleans,  La.  360 

Ohio  Mechanics   Institute Cincinnati.   Ohio  360 

Chicago  Daily  Drovers  Journal Chicago,  III.  286 

I.  R.  Nelson  Co Newark,  N.  J.  263 

University  of  Missouri Columbia,  Mo.  254 

Omaha   Grain   Exchange Omaha,    Nebr.  286 

Harrisburg  Sporting  Goods  Co Harrisburg,  Pa.  266 

Parker  High  School Dayton,  Ohio  283 

Lake  Shore  Tire  Co Sandusky,  Ohio  240 

Bangor  Railway  &.  Electric  Co Bangor,  Me.  240 

Connecticut  Agricultural    College Storrs.    Conn.  283 

F.  A.  Doherty  Automotive  and  Radio  Equipment  Co Saginaw,  Mich.  254 

Ott   Radio.   Inc LaCrosse,   Wis.  244 

Lake  Avenue  Baptist  Church Rochester,  N.  Y.  283 

Robert  F.  Weinig Dover,  Ohio  266 

Haverford  College.  Radio  Club Haverford,  Pa.  261 

Scott  High  School,  N.  W.  B.  Foley Toledo,  Ohio  270 

Victor  Talking  Machine  Co Camden,  N.  J.  226 

College  of  Wooster Wooster,  Ohio  234 

Henry  B.  Joy Mt.  Clemens.  Mich.  270 

John  Magaldi.  Jr Philadelphia.  Pa.  242 

Coliseum  Place  Baptist  Church New  Orleans,  La.  263 

A.   H.  Grebe  &   Co Richmond   Hill,   N.  Y.  316 

Purdue  University W.    Lafayette,   Ind.  283 

The  Dayton  Co Minneapolis,  Minn.  417 

Wireless  Phone  Corp Paterson,  N.  J.  244 

James     Millikin     University Decatur,     111.  360 

Wortham-Cirter  Publishing  Co.  (Star  Telegram) Fort  Worth,  Tex,  476 

Erner  &  Hopkins  Co Columbus,  Ohio  423 

John  H.  Stenger,  Jr Wilkes-Barre,  Pa.  254 

Western  Electric  Co New  York,  N.  Y.  492 

Barbey  Battery  Service Reading,   Pa.  234 

Irving  Vermilya Mattapoisett,  Mass.  248 

J.  Irving  Bell Port  Huron,  Mich.  246 

Grace  Covenant  Presbyterian   Church Richmond,   Va.  283 

H.    Leslie   Atlass Chicago,  111.  226 

Blake.  A.  B Wilmington,  N.  C.  275 

Petoskey    High    School Petoskey,   Mich.  246 

Peoples   Pulpit   Asso Rossville.    N.   Y.  273 

First    Baptist    Church New    Orleans,  La.  252 

Lloyd    Brothers Philadelphia,    Pa.  234 

Jenks    Motor    Sales    Co Monmouth,    111.  224 

Johnstown  Radio  Co Johnstown,  Pa.  245 

Ruffner     Junior     High     School Norfolk,  Va.  222 

Washington  Light  Infantry  Co.  "B"  llstn  lnf Charleston.  S.  C.  268 

Noble  B.  Watsoo Indianapolis,  I  nd.  227 

Southtowu    Economist    Church Chicago,    111.  266 

T  &  H  Radio  Co Anthony,  Kans.  254 

Pennsylvania  State   Police Butler.  Pa.  286 

D.  W.  May,  Inc Newark,  N.  J.  260 

Southern    Radio    Corp Charlotte,    N.    C.  360 

Westinghouse     E.     &     M.     Co Springfield,     Mass.  337 

St.  Lawrence  University Canton,  N.  Y.  280 

Kaufmann  &  Baer  Co Pittsburgh,  Pa.  462 

Clyde  R.  Randall New  Orleans.  La.  268 

Entrekin  Electric   Co Columbus.  Ohio  286 

Nebraska  Wesleyan  University University  Place.  Nebr.  283 

Alfred  P.  Daniel Houston,  Texas  263 

St.  Olaf  College Northtield,   Minn.  360 

Sanders  &  Stayman  Co Baltimore.  Md.  275 

Chesapeake  &  Potomac  Telephone  Co Washington.  D.  C.  469 

Alamo  Radio  Eleotric  Co San  Antonio.  Tex.  360 

W.  H.  Dunwoody  Industrial  Institute Minneapolis,  Minn.  280 

State  CoUege  ol  Mines Rapid  City.  S.  Dak.  240 

Durham    rt   Co Philadelphia.    Pa.  286 

J.  C.  Dice  Electric  Co Little  Rock,  Ark.  3w> 

University   of    Vermont Burlington,  Vt.  360 

Carthage    College    Carthage,    111.  246 

Charles  W.  Heimbach Allentowu.  Pa.  280 

University  of  Michigan Ann  Arbor.  Mich.  280 

Wilbur  G.   Voliva Zion.  111.  345 

Uhalt  Radio  Co New-   Orleans.  La.  263 

Paul  J.   Miller Pittsburgh.   Pa.  236 

Howard  S.  Williams  (Portable) Pascagoula.  Miss.  268 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


75 


A  6-Tube  Baby  Grand 
Super  Het 

(Continued  from  pa^e  66) 
the  fifth  (detector)  tube. 

It  will  be  necessary  to  try  several 
capacities  of  fixed  condensers  across  the 
primary  of  the  audio  transformer.  The 
value  to  use  may  run  as  high  as  .0075 
or  as  low  as  .0025.  The  .0275  condenser 
across  the  primary  of  the  output  trans- 
former is  rather  critical,  as  is  also  the 
one  across  the  primary  of  the  audio 
transformer.  The  condensers  C-4  and 
C-2  are  rather  critical,  and  unless  they 
are  nearly  the  right  capacity,  the  oscilla- 
tor circuit  will  have  a  tendency  to  be 
erratic  in  its  operation  or  possibly  slop 
over  into  the  adjacent  circuit  causing 
peculiar  symptoms.  The  same  thing  that 
has  been  said  a  number  of  times  before 
should  be  repeated;  namely:  that  fixed 
condensers,  while  given  rated  capacity 
markings,  vary  as  a  usual  thing  from  the 
rated  capacity  by  as  much  as  15  to  20 
per  cent.  The  writer  has  frequently  run 
across  fixed  condensers  which  had  such  high 
conductance  as  to  be  useless  as  condensers. 

A  1  MF  condenser  of  1  MF  capacity 
is  placed  between  the  negative  "B"  and 
plus  "B"  45  volt  posts.  This  condenser 
is  shown  at  the  extreme  left  end  of  the 
baseboard  at  the  back.  No  capacity  less 
than  1  MF  should  be  used,  and  usually 
it  could  be  increased  to  2  MF  without 
actually  causing  any  ill  effects. 
Tuning  The  Set 

By  using  good  straight  line  condensers, 
it  will  be  possible  to  lay  out  a  chart 
whereby  you  can  predict,  with  almost 
startling  certainty,  the  dial  setting  for 
any  station  that  you  may  wish  to  reach. 

It  is  to  be  understood,  of  course,  that 
the  oscillator  dial  has  two  settings  for 
every  station.  Usually  it  will  be  found 
that  one  of  these  settings  gives  results 
superior  to  the  other.  It  may  be  neces- 
sary to  make  a  slight  adjustment  of  the 
loop  condenser  when  changing  the  oscilla- 
tor settings  so  as  to  secure  the  greatest 
efficiency  in  tuning. 


Low  Loss  Products 


Master  Tuning  Coil 
Perfectly  Balanced 

Head  Phone 
Low  Loss  Condenser 

High  grade,  standard  radio  products  that 
will  increase  the  efficiency  of  an>  set  and 
add  to  the  satisfaction  of  the  user.  Am- 
bassador Low  Loss  Products  have  long  been 
the  choice  of  particular   fans.     See  there- — 

them,  and  you  will  choose  them  too. 
At  All  Good  Dealers 

Vrilefo 


AMBASSADOR  SALES  COMPANY 
108  Greenwich  St.,  New  Yo-k 
326  W.Madison  St..    Chicago 


RADIO  BARGAINS 

Radio  Set  Complete,  with  R.  C  A.  tube.  Bat- 
teries, and  Antenna  Equipment,   ready  to 

tune  in JI&.SS 

Journal  Low- Loss  Coils,  set 3.95 

Engraved  Binding  Posts.  Complete  set 1*00 

Guaranteed  Crystals 59 

Famous  Chapin  Transformers,  o-l  or  3-1 3.85 

All  mail  orders  filled  momptly  C.  O.  D.  Parcel  Post. 
FREE— Write  to-.Big  Bargain  Sheet 

rad:o-electric  mfg.  co. 

Dept.    5.    442  Clinton    Ave..    Newark,    N.   J. 


CLASSIFIED  ADVERTISEMENTS 


Don't  overlook  the  value  of 
RADIO  AGE'S  classified  adver- 
tisements. Many  such  messages 
have  paved  the  way  to  independent 
incomes. 

The  classified  advertising  rates 
are  but  ten  cents  per  word  for  a 
single  insertion.  Liberal  discounts 
are     allowed     on     three,     six     and 


twelve  -time  insertions,  of  five, 
fifteen  and  thirty  per  cent,  res- 
pectively. Unless  placed  through 
an  accredited  advertising  agency, 
cash  should  accompany  all  orders. 
Name  and  address  must  be  in- 
cluded at  foregoing  rates  and  no 
advertisement  of  less  han  ten 
words    will    be    accepted. 


RADIO  SALESMEN  WANTED— Make  $50.00  weekly 
■elling  standard,  well  advertised  radio  sets  and  part*. 
No  investment  required.  Write  for  free  outfit.  Desk 
27.  WAVELAND  RADIO  COMPANY,  1027  N.  State  St., 
Chicago. 


FOR  SALE— 3  Pfanstiehl  tuning  units.  3  Cardwell  Con- 
densers, 1  Qradleyometer,  2  Bradleystats.  All  goods 
New.      Earl  Price,  Lodi,  Wis. 


90c  an 

hour 

to  advertise 

and  distribute 

iple 

to  con- 

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quick     for     territory    a 

rid 

Amari 

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2130  American 

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WANTED— To  complete  my  set  RADIO  AGE  need 
August,  September,  October,  November,  1923,  issues, 
bound  or  unbound.  Advise  price.  Lloyd  C.  Henning, 
Holbrook,  Arizona. 


's,  women's.  Children's  shoes  direct,  sav- 
mer  over  40' c-  Experience  unnecessary  - 
upplied.  Big  weekly  permanent  income. 
r  Tanners  Mfg.  Co, ,  1 334  C.  St. ,  Boston,  Mass. 


BUSINESS     OPPORTUNITIES 


RADIO  CIRCUITS 


DEALERS — Write  for  on 
Radio    Merchandise. 
Dept.  D,  1830  Wilson  Av 


illustrated  catalog  of  reliable 
>ssiter-Manning  Corporation, 
,  Chicago,  III. 


SPECIAL  FOR  JANUARY 
The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne,  fully 
illustrated,  and  RADIO  AGE,  for  $2.50.      Price  of  book- 
let alone  is  50c.     Send  check,  currency  or  money,order 
to  RADIO  AGE,  500  N.   Dearborn  Street,  Chicago. 


MISCELLANEOUS 


AN  OLD  AND  WELL  ESTABLISHED  MANUFACTUR- 
ING COMPANY  IN  THE  MIDDLE  WEST  WITH  LARGE 
WELL  EQUIPPED  PLANTS  AND  UNUSUAL  FINAN- 
CIAL RESOURCES.  DESIRING  TO  ENTER  THE  RADIO 
FIELD  WILL  CONSIDER  THE  MANUFACTURE  AND 
SALE  OF  RADIO  SETS  OR  DEVICES  OF  OUTSTAND- 
ING AND  UNUSUAL  MERIT  ON  A  ROYALTY  BASIS. 
ADDRESS  BOX   1  A.   RADIO  AGE. 


158  Genuine  Foreign  Stamps.  Mexico  War  Issues. 
Venezuela,  Salvador  and  India  Service.  Guatemala, 
China,  etc.,  only  5c.  Finest  approval  sheets,  50  to 
60  percent.  Agents  Wanted.  Big  72-p.  Lists  Free. 
We  Buy  Stamps.  Established  20  Years.  Hussman 
Stamp  Co.,  Dept.  152,  St.  Louis,  Mo. 


FOR  SALE 


Standard  soderlet 


I'nunii-     circuit.      une     aonar     oui.       to 
i  Seward,  Jr..  New  Paltz,  New  York.  N.  Y 


■  ■luing  post  attach- 
dollar     bill.      Postpaid. 

M V I-       M       XT 


Make     Big     Money.      Safe     and     Lock     Expert.      Wayne 
Strong,  3800  Lan  Franco,  St.    Los  Angeles,  Calif. 

Classified  ad  copy  for    the  February  issue  mus 


BLUEPRINTS— Make  your  own  set  from  proven 
original  and  up-to-the  minute  blueprints.  The  follow- 
ing are  merely  three  of  a  choice  of  almost  one  hundred 
different    types: 

HT-1-3— Five    tube    neutrodyne— 50c. 

FB-6 — Three-honeycomb     regenerative — 35c. 

D10-4— Diode    single    circuit— 25c. 

All  three  of  above,  for  $1.00. 

These  tested  blueprints  are  all  made  up  in  easily 
read  circuit  drawings.  MIDLAND  PRODUCTS  COM- 
PANY, 1413  Hood  Ave.,  Chicago,  III.     Ask  for  our  com- 

plete  iist.   No.   Rll. 

100   VOLT    EDISON    TYPE    "B"    BATTERY,  knocked 
down.      Parts  and  plans— complete,  112  SO.     Lane  Mfg., 
.2937  W.   Lake,  Chicago, 
reach  RADIO  AGE  not  later  than  December  25. 


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76 


RADIO  AGE  for  January,  1925 


The  Magazine  of  the  Hour 


WCBH       University     of     Miss Olford. 

WCBI        Niooll,  Duncan  &  Hush Bemii 

WCBJ       J.  G.  Mius Jenniugs,  Louisiana 

WCBK      E.    Richard  Hall St.  Petersbure.   Fla. 

WCBL       Northern   Radio  Mfg.  Co Houlton,  Me. 

WCBM     Charles  Sw  irz Baltimore,  Md. 

WCBN      James  P.  Bolind .Ft.  Benj.  Harrison.  Ind. 

WCBO      The  Radio  Shop.  Ino Memphis.  Tenn. 

WCBQ      First   Biptist    Church Nashville.    Tenn. 

WCBR      C.  H.  Mejster Providence,    R.  I. 

WCBT       Clark  University.   Collegiate  Dept Worcester,  Mass. 

WCBU      Arnold  Wireless  Supply  Co Arnold.  Pa. 

WCBV       Tullahoma  Radio  Club Tullahoma,  Tenn. 

WCBW     George  P.  Rankin.  Jr.,  and  Maitland  Solomon Macon.  Ga. 

WCBX      Radio  Shop  of  Newark  (Herman  Lubinsky) Newark.  N.  J. 

WCBY      The  Forks  Electrical  Shop Buck  Hill  Falls,  Pa. 

WCBZ       Coppotelli  Bros.  Music  House Chicago  Heights.  111. 

WCCO      Washburn-Crosbv    Co Twin    Cities.    Minn. 

WCK  Stiz-B.er  Fuller  D.  G.  Co St.  Louis.  Mo. 

WCX  Free     Press Detroit,     Mich. 

WDAE      Tampa  Dady  Times Tampa.  Fla. 

WDAF       Kansas   City   Star Kansas   City.    Mo. 

WDAG      J.  Laurence  Martin Amarillo.  Tei. 

WDAH      Trinity  Methodist  Church   (South) El  Paso.  Tel. 

WDAR      Lit    Brothers Philadelphia.     Pa. 

WDAS       Samuel    A.    Waits Worcester,    Mass. 

WDAU      Slocurn    Kilburn New    Bedford.    Mass. 

WDAY      Radio  Equipment  Corp Fargo.    N.    Dak. 

WDBA      Fred     Ray Columbus,     Ga. 

WDBB      A.  H.  Waite  &  Co.,  Ino Taunton,  Mass. 

WDBC      Kirk.    Johnson    &    Co Lancaster.    Pa. 

WDBD      Herman     Edivin     Burns Martinsburir,     W.     Va. 

WDBF       Robert  G.  Phillips Youngstown.  Ohio 

WDBH      C.  T.  Scherer  Co Worcester.  Mass. 

WDBI        Radio  Specialty  Co St.   Petersburg,   Fla. 

WDBJ        Richardson    W  lyltnd    Electric    Corp Roanoke,    Va. 

WDBL      Wise.  Dept.  of  Markets '." Stevens  Point.  Wis. 

WDBN      Electric  Light  &  Power  Co Bangor.  Me. 

WDBO       Rollins     College    Inc Winter     Park.     Fla. 

WDBP       Superior   State    Normal   School Superior,    Wis. 

WDBQ      Morton   Radio  Supply  Co Salem,  N.  J. 

WDBR      Tremont  Temple  Baptist  Church : Boston,  Mass. 

WDBS      S.  M.  K.  Radio  Corp Dayton,  Ohio 

WDBT      Taylor's  Book  Store Hattiesburg,  Miss. 

WOBV       The  Strand  Theatre Fort   Wayne.  Ind. 

WDBW     Tne  Radio  Den Columbia,  Tenn. 

WDBX      Otto  Baur : New  York,  N.  Y. 

WDBY      North    Shore    Congregational    Church Chicago,    111. 

WDBZ       Boy  Scouts.  City  Hall Kingstown.  N.  Y. 

WDM        Church  of  the  Covenant Washington,   D.  C. 

WDZ]        J.  L.  Bush ^ Tuscola.  III. 

WEAA       F.   D.  Fallain Flint,  Mich. 

WEAF       American  Telephone  &  Telegraph  Co : New  York,  N.  Y. 

WEAH       Wichita   Board  of  Trade Wichita,   Kans. 

WEAI         Cornell  University Ithaca,  N.  Y. 

WEAJ        University  of  South  Dakota Vermilion.  S.  Dak. 

WEAM  Borough  of  North  Plainfield  (W.  Gibson  Butttield) .  .  .North  Plainneld,  N.  J 

WEAN      Shepard    Co Providence,  R.    I. 

WEAO       Ohio  State  University Columbus.  Ohio 

WEAP       Mobile   Radio   Co Mobile.   Ala. 

WEAU       Davidson  Bros.  Co - Sioui  City,  Iowa 

WEAY       Iris  Theatre  (Will  HorowiB,  Jr.) Houston.  Texas 

WEB  BenwooJ    Co St.    Louis,    Mo. 

WEBA       Electric  Shop Highland  Park.  N.J. 

WEBC       Walter    Cecil    Bridges Superior,    Wis. 

WEBD       Electrical  Equipment  and  Service  Co ." Anderson,  Ind. 

WEBE       Roy  W.    Walker Cambridge,  Ohio 

WEBH       Edgewater  Beach   Broadcasting   Station Chicago.   111. 

WEBI        Walter  H.   Gibbons Salisbury,   Md. 

WEBJ       Third  Avenue  Railway  Co New  York,  N.  Y. 

WEBP       E.  B.  Pedicord New  Orleans,   La. 

WEBT       The  Day  tan  Coop.  Indus)  ri  il  Hi-li  School Dayton,  Ohio 

WEBU       DeLand  Piano  &  Music  Co. .  131)  Boulevard  St DeLand.    Fla. 

WEBW      Beloit  College Beloit,  Wise. 

WEBX       John   E.   Cain.   Jr Nashville,   Tenn. 

WEB  Y       Hobart      Radio      Co Roslindale,      Mass. 

WEEI         The  Edison  Electric  Illuminating  Co Boston.   Mass. 

WEV  Hulbert-Still   Eleo.   Co Houston,    Tex. 

WEW         St.     Louis     University St.     Louis,     Mo. 

WFAA       Dallas  News  &   Dallas  Journal Dallas.  Texas 

WFAM     Times  Publishing  Co St.  Cloud,  Minn. 

WFAN       Hutchinson  Electric  Service  Co Hutchinson,  Minn. 

WFAV  University  of  Nebraska,  Department  of  Electrical  Engineering.  .Lincoln,  Nebr. 

WFBB       Eureka  College :..... Eureka.  111. 

WFBG      The  Wm.  F.  Cable  Co Altoona.  Pa. 

WFBH      Concourse  Radio  Corporation New  York,  N.  Y. 

WFBJ        St.  John's  University Collegeville,   Minn. 

WFBW      Ainsworth-Gates       Radio      Co Cincinnati,  Ohio 

WFI  Strawbridge  and  Clothier Philadelphia,  Pa. 

WGAL      Lancaster  Electric  Supply  <fe  Construction  Co Lancaster,  Pa. 

WGAN      Cecil     E.     Lloyd Pensacola,     Fla. 

WGAQ     Youree  Hotel  Shreveport,  La. 

WGAZ      South  Bend  Tribune South  Bend,  Ind. 

WGBC      First  Baptist  Church Memphis,  Tenn. 

WGBS      Gimbel  Brothers — New  York.  N.  Y. 

WGI  American   R.  &  R.  Co Medford  Hillside,   Mass. 

WGL         Thos.  F.  J.  Howlett.  . Philadelphia.  Pa. 

WGN         The    Tribune    Co Chicago.    IU. 

WGR  Federal  T.  and  T.  Co Buffalo,  N.  Y. 

WGY         General  Elec.  Co .-;■ .„ Schenectady.  N.  Y. 

WHA         University    of    Wisconsin Madison.    Wis. 

WHAA      State  University  of  Iowa Iowa  City.  Iowa 

WHAD      Marquette  University Milwaukee.  Wis. 

WHAG      University  of  Cincinnati Cincinnati.  Ohio 

WHAH      Hater  Supply   Co Joplin,    Mo. 

WHAM     University  of  Rochester  (Eastman  School  of  Music) Rochester.  N.  Y. 

WHAR      SeosideHouse Atlantic  City,  N.J. 

WHAS       Courier-Journal  &  Louisville  Times Louisville.  Ky. 

WHAV      Wilmington  Kloctrical  Specialty  Co Wilmington.  Del. 

WHAZ       Rensselaer  Polytechnic  Institute Troy,  N.  Y. 

WHB  Sweeney  School   Co Kansas  City.  Mo. 

WHK  Radiovox     Company Cleveland.     Ohio 

WHN         George    Schubel New    York.    N.    Y. 

WHO         Bankers    Life    Co Dos    Moines,    la. 

WIAB        Joslyn  Automobile  Co Rockford,   111. 

WIAC        Galveston  Tribune Galveston.  Texas 

WIAD       Howard  R.  Miller Philadelphia,  Pa. 

WIAK        Journal-Stockman   Co Omaha,  Nebr. 

WIAQ       Chronicle   Publishing   Co Marion,    Ind. 

WIAS         Home  Electric  Co Burlington.  Iowa 

WIK  K.    &    L.    Co McKeesport,     Pa. 

WIL  Continental    Electric    Supply    Co Washington,    D.     C. 

WIP  Gimbel  Bros Philadelphia,   Pa. 

WJ  AB       American  Electric  Co Lincoln.  Neb. 

WJAD       Jackson's  Radio  Engineering  Laboratories Waco.  Texas 

WJAG        Norfolk  Daily  News Norfolk.  Nebr. 

WJAK       Clifford  L.  White Greentown.  la. 

WJAM      D.  M.  Perham Cedar  Rapids,  Iowa 

WJAN       Peoria    Star Peoria,    111. 

WJAR       The  Out.      Co.  (J.  Samuels  &  Bro.) Providence.  R.  I. 

WJAS        Pittsburgh  Radio  Supply  House Pittsburgh,  Pa 

WJAX       Union  Trust  Co Cleveland,  Ohio 

WJAZ       Chicago    Radio   Laboratory Chicago,    111. 

WJD  Donison      University Grantville,       Ohio 

WJJD       Supreme  Lodge.  Loyal  Order  of  Moose Mooseheart,     111. 

WJY  Radio  Corp.  of  Ami New  York,  N.  Y. 

WJZ  Radio  Corp.  of  ami New  York,  N.  Y. 

WK  AA      H.  F.  Paar Cedar  Rapids,  Iowa 

WKAD      Cbas.  Looff  (Crescent  Park) East  Providence,  R.  I. 

WKAF      W.  S.  Radio  Supply  Co Wichita  Falls.  Texas 

WKAN      United  Battery  Service  Co Montgomery,  Ala. 


242 

WKAP 

240 

WKAQ 

244 

WKAR 

266 

WKAV 

280 

WKBF 

229 

WKY 

266 

WLAG 

250 

WLAL 

236 

WLAP 

246 

WLAQ 

233 

WLAW 

254 

WLAX 

252 

WLB 

226 

WLBL 

233 

WLS 

268 

WLW 

248 

WMAC 

417 

WMAF 

360 

WMAH 

517 

WMAK 

360 

WMAL 

411 

WMAN 

263 

WMAQ 

268 

WMAV 

395 

WMAY 

360 

WMAZ 

360 

WMC 

244 

WMU 

236 

WNAC 

229 

WNAD 

258 

WNAL 

268 

WNAP 

246 

WNAR 

268 

WNAT 

226 

WNAW 

229 

WNAX 

278 

WNYC 

252 

WOAC 

240 

WOAE 

261 

WOAF 

234 

WOAG 

256 

WOAI 

283 

WOAN 

236 

WOAO 

258 

WOAR 

268 

WOAT 

233 

WOAV 

258 

WOAW 

233 

WOAX 

234 

woe 

278 

WOI 

250 

WOO 

492 

WOQ 

280 

WOR 

286 

WOS 

283 

WPAB 

286 

WPAC 

273 

WPAJ 

360 

WPAK 

263 

WPAL 

275 

WPAR 

360 

WPAU 

273 

WPAZ 

233 

WQAA 

242 

WQAC 

246 

WQAE 

248 

WQAF 

370 

WQAM 

242 

WQAN 

273 

WQAO 

280 

WQAQ 

270 

WQAS 

258 

WQAX 

283 

WQJ 

263 

WRAF 

226 

WRAL 

303 

WRAM 

263 

WRAN 

280 

WRAO 

476 

WRAV 

273 

WRAW 

286 

WRAX 

275 

WRBC 

240 

WRC 

261 

WREO 

273 

WRK 

236 

WRL 

309 

WRM 

395 

WRR 

248 

WRW 

360 

WSAB 

252 

WSAC 

360 

WSAD 

266 

WSAI 

316 

WSAJ 

360 

WSAP 

360 

WSAR 

370 

WSAU 

319 

WSAV 

380 

WSAY 

275 

WSAZ 

484 

WSB 

280 

WSL 

222 

WSOE 

283 

WSY 

283 

WTAB 

275 

WTAC 

400 

WTAF 

360 

WTAL 

380 

WTAM 

411 

WTAP 

283 

WTAQ 

360 

WTAR 

526 

WTAS 

252 

WTAT 

360 

WTAU 

254 

WTAW 

278 

WTAX 

226 

WTAY 

283 

WTAZ 

234 

WTG 

360 

WTX 

509 

WWAD 

229 

WWAE 

360 

WW1 

283 

WWJ 

254 

WWL 

268 

WWOA 

280 

WCEE 

360 

WFBC 

286 

WFBR 

390 

WFBT 

268 

WBGA 

229 

KFHL 

278 

KFNJ 

405 

KFRX 

455 

KFRM 

278 

KFRN 

240 

KFRO 

360 

WFBQ 

226 

WSAB 

Dutee  W.  Flint Cranston,  R.  I.  360 

Radio  Corp.  of  Porto  Rico San  Juan,  P.  R.  360 

Michigan  Agriculture  College East  Lansing  Mich.  280 

Laconia  Radio  Club Laconia.   N.  H.  254 

Dutee  Wilcox  Flint Cransten,  Rhode  Island  286 

Wky      Radio      shop OkU      City,        Okla.  360 

Cutting  &  Washington  Radio  Corp Minneapolis,  Minn.  417 

Naylor  Electrical  Co Tulsa,   Okla.  360 

Wm.  V.  Jordan Louisville,  Ky.  286 

Arthur  E.  Shilling Kalamazoo,  Mich.  283 

Police  Dept.,  City  of  New  York ; New  York.N.  Y.  360 

Putnam  Electric  Co Greencastle,  Ind.  231 

University  of   Minnesota Minneapolis,    Minn.  278 

Wisconsin  State  Dept.  of  Markets Stevenspoint,  Wis.  278 

Sears    Roebuck    &    Co Chicago,    111.  345 

Crosley  Mfg.  Co Cincinnati.  Ohio  423 

J.  Edw.  Page  (Olive  B.  Meredith) .  . .- Cazenovia,  N.  Y.  261 

Round  Hills  Radio  Corp Dartmouth,  Mass.  360 

General  Supply  Co Lincoln,   Nebr.  254 

Norton  Laboratories Lockport,   N.  Y.  273 

Trenton  Hardware  Co Trgnton,  N.  J.  256 

First  Baptist  Church .Columbus,  Ohio  286 

Chicago  Daily  News Chicago,  111.  448 

Alabama   Polytechnic   Institute Auburn,   Ala.  250 

Kingshighway  Presbyterian  Church St.  Louis,  Mo.  280 

Mercer  University Macon,  Ga.  261 

Commercial     Appeal Menphis,       Tenn.  BOO 

Doubledal-Hill  Elec.  Co Washington,    D.  C.  261 

Shepard  Stores Boston,  Mass.  278 

University  of  Oklahoma Norman,  Okla.  254 

Omaha  Central  High  School Omaha,  Nebr.  258 

Wittenberg  College Springfield,  Ohio  275 

First  Christian  Church Butler,  Mo.  231 

Lennig  Brothers  Co-  (Frederick  Lennig) \  Philadelphia,  Pa.  250 

Peninsular  Radio  Club  (Henry  Kunzmann) Fort  Monroe,  Va.  240 

Dakota  Radio  Apparatus  Co ; Yankton.  S.  Dak.  244 

Dept.  of  Plant  and  Structures New  York,  N.  Y.  526 

Page   Organ  Co Lima,  Ohio  266 

Midland  College Fremont,  Nebr.  280 

Tyler    Commercial   College Tyler,    Texas  360 

Apollo  Theater  (Belvidere  Amusement  Co.) Belvidere,  111.  273 

Southern  Equipment  Co San  Antonio,  Texas  385 

Vaughn  Conservatory  of  Music  (James  D.  Vaughn) ....  Lawrenceburg,  Tenn.  360 

Lyradion  Mfg.  Co Mlshawaka,  Ind.  360 

Lundskow,  Henry  P Kenosha,  Wis.  229 

Boyd  M.  Hamp Wilmington,  Del.  360 

Pennsylvania  Nation.il  Guard.  2d  Battalion,   112th   Infantry Erie.  Pa.  242 

Woodmen  of  the  World Omaha,  Nebr.  526 

Franklyn  J.  Wolff Trenton,  N.  J.  240 

Palmer    School    of    Chiropractic Davenport,     la.  484 

Iowa      State      College Ames,       la.  360 

John       Wanamaker Philadelphia,        Pa.  509 

Western     Radio    Co Kansas     City,      Mo.  360 

L.   Bamberger  and   Co. Newark,    N.  J.  405 

State     Marketing    Bureau Jefferson     City,      Mo.  441 

Pennsylvania  Sure  (Allege State  College,  Pa.  283 

Donaldson  Radio  Co .Okmulgee,  Okla.  360 

Doolittle  Radio  Corp New  Haven,  Conn.  268 

North  Dakota  Agricultural  College Agricultural  College.  N.  D.  283 

Superior  Radio  &  Telephone  Equipment  Co Columbus,  Ohio  286 

Ward  Battery  and  RadioCo Beloit,  Kans.  236 

Concordia  College Moorhead,   Minn.  286 

John  R.  Koch  (Dr.) Charleston,  W.  Va.  273 

Horace  A.  Beale,   Jr Parkersburg,  Pa.  270 

E.  B.  Gish Amarillo,  Texas  234 

Moore  Radio  News  Station  (Edmund  B.  Moore) Springfield^  Vt.  275 

Sandusky   Register Sandusky,   Ohio  240 

Electrical     Equipment     Co Miami,     Fla.  283 

Scranton  Times Scranton,  Pa.  280 

Calvary  Baptist  Church New  York,  N.  Y.  360 

Abilene  Daily  Reporter  (West  Texas  Radio  Co.) Abilene,  Texas  360 

Prince- Walter  Co Lowell,   Mass.  266 

Radio  Equipment  Company Peoria,   111.  248 

Calumet    Rainbo    Broadcasting    Co Chicago,     111.  448 

The  Radio  Club  (Inc.) Laporte,  Ind.  224 

Northern  States  Power  Co St.  Croix  Falls,  Wis.  248 

Lombard  College Galesburg,  III.  244 

Black  Hawk  Electric  il  Co .  Waterloo,  Iowa  236 

St.  Louis  RidioServijeCo 3t.  Louis,  Mo.  263 

Antioch  College Yellow  Springs,  Ohio  242 

Avenue  Radio  Shop  (Horace  D.  Good) Reading,  Pa.  238 

Flaxon's  Garage Gloucester  City,  N.  J.  268 

Imanuel  Lutheran  Church Valparaiso,  Ind.  278 

Ridio  Corp.  of  Ami Washington,    D.  C.  469 

Reo  Motor  Cir  Ca. L  msin?,  Mich.  288 

Doron     Bros Himtlton,      Ohio  360 

Union  College '■ : Schenectady,    N.  Y.  270 

University      of      Illinois Urbana.       HI.  273 

Police  and  Fire  Signal  Department Dallas.    Tex.  360 

Tarrytown  Radio   Re-..   Labs Tarrytown,     N.  Y.  273 

Southeast  Mi^ou-i  State  Teachers  College Cape  Girardeau,  Mo.  360 

Clemson  Agricultural  College Clemson  College,  S.  C.  360 

J.  A.  Foster  Co Providence,  R.  I.  26l 

United  States  PI  -.ying  Cards  Co Cincinnati,  Ohio  309 

Grove  City  College ; Grove  City,  Pa.  258 

Seventh  Day  Adventist  Church • New  York,  N.  Y.  263 

Doughty  &  WeMi  Electrical  Co Fall  River,  Mass.  254 

Camo  Marienfeli.. Chesham.  N.  H.  229 

C.   W.   Vick   Ra  lio  Construction   Co Houston,  Tex.  360 

Irving  Austin  (Port  Chester  Chamber  of  Commerce) .  .Port  Chester,  N.  Y.  233 

Chas.  Electric  Shop Pomeroy,  Ohio  258 

Atlanta    Journal .V Atlanta,     Gai  423 

J.  and  M.  Elec.  Co XTtica,  N.  Y.  273 

School    of   Engineering .l.  ..  .Milwaukee.     Wis.  246 

Alabama     Power    Co Birmingham,     Ala.  360 

Fall  River  Daily  Herald  Publishing  Co Fall  River,  Mass.  248 

Penn  Traffic   Co .Johnstown,   Pa.  360 

Louis  J.  Gallo New  Orleans,  La.  242 

Toledo  Radio  &  Electric  Co ; , Toledo,   Ohio  252 

Willard  Storage  Battery  Co : Cleveland,  Ohio  390 

Cambridge  Radio  &  Electric  Co 7. Cambridge,  111.  242 

S.  H.  Van'GbfdbnjA  Son Osseo,  Wis.  22'0 

Reliance   Eectric   Co Norfolk.   Va.  280 

Charles  E.   Erbstein Elgin.  111.  286 

Edison  Electric  Illuminating  Co -.  Boston,  Mass.  (portable)  244 

Ruegg  Battery  &  Electric  Co " Tecuraseh,  Nebr.  242 

Agricultural  &  Mechanic  ,!  College  of  Texas College  Station, "Tex  280 

Williams   Hardware   Co Streator.    IU.  231 

Oak  Leaves  Broadcasting  Station Oak  Park.  111.  283 

Thomas  J.   McGuire Lambertville.    N.   J.  283 

Kansas     State     Agricultural     College Manhattan,     Kan3.  273 

H.  G.  Saal  Co Chicago.  111.  268 

Wright  &  Wright  (Ino.) Philadelphia.  Pa.  360 

The  Alamo   Ball    Room Joliet.   IU.  242 

Ford   Motor  Co Dearborn.    Mich.  273 

Detroit  News  (Evening  News  Assn.) Detroit,  Mich.  517 

Loyola   University New    Orleans,    La.  2  60 

Michigan  Oollege    of  Mines Houghton,  Mich.  244 

Charles  E.   Erbstein.   Villa  Olivia near  Elgin,  III.  536 

First  Baptist  Church Knoxv  lie,  Tenn.  250 

Fifth  Inf.  Md.  Nafl  Guard,  5th  Res.  Armory, Baltimore,  Md.  254 

Gloucester  Co.  Civic  League.  , Pitman,  N.  J.  231 

Jones  Elec.  &  Radio  Mfg.  Co .  Baltimore,  Md.  254 

Penn     College Oskaloosa,     Iowa  240 

Central  Mo.  State  Teachers  Cullege , Warrensburg,  Mo.  234 

J.    Gordon    Klemgard ■ Pullman.    Wash.  217 

James   F.    Boland .  Fort   Sill,    Okla.  263 

M.  Laurence  Short Hanford.  Calif.  224 

Curtis   Printing   Co Ft.   Worth,   Tex.  246 

Wynne  Radio  Co Raleigh,  N.  C.  252 

Southeast  Mo.  State  Teacher*  College Cape  Girardeau,  Mo.  275 


RADIO  AGE  for  January,   1925 


The  Mat 


of  the  Hour 


Premier 

"Lo  Loss" 

TUBE 
SOCKET 

90  Cents 
All  Types 

Strengthen  Your 
Speaker    Volume 

Conserve  the  current  at  full  strength  and  strengthen 
your  speaker  volume  with  this  radically  different  socket. 
Has  the  lowest  insulation  leakage  to  radio  frequency 
current.  Bakeltte  between  terminals  is  purposely  thin 
and  all  metallic  parts  are  placed  so  as  to  reduce  capacity 
between  them  and  the  terminals  to  the  very  minimum. 
Contact  springs  in  the  "LO  LOSS"  are  in  one  piece 
from  binding  post  to  tip  of  tube.  The  skeleton  tube 
barrel  permits  inspection  of  contact  at  prong  tips  while 
tube  is  in  the  socket.  The  contact  springs  automatically 
clean  the  tube  prongs  as  the  tube  is  inserted,  insuring 
good  contact  always.  The  new  tube  lock  with  the  cam 
action  makes  the  proper  insertion  of  the  lube  easy.  A 
twist  of  the  wrist  does  it.  The  terminals  are  curved  and 
irill  stand  unusual  deflection  without  setting. 

Write  for  Free  Bulletin  No.  94  showing  complete 
line  of  Premier  Quality  Radio  Parts.  Ask  your 
dealer  if  he  has  Premier  free  hook-ups.  If  not,  send 
his  name  and  receive  a  set  free. 

3803  Ravenswood  Ave.,  Chicago 

pnmtm 

Quality  Radio  Tarts 


What  to  Expect  from  Your  Set 


By  Kenneth  C.  Smith 

\  MAN  in  the  Middle  West  once  heard 
•^A-  2LO,  London,  England,  on  an 
ordinary  3-tube  set.  It  was  an  accident 
— one  of  those  unusual,  inexplicable 
accidents  that  happen  so  often  in  Radio. 
He  never  got  out  of  the  U.  S.  A.  again, 
but  for  ever  after  he  bragged  that  his 
set    would    bring    in    London,    England. 

I  don't  know  why  it  is,  but  there  is 
something  about  radio  that  seems  to 
encourage  extravagant  statements,  not 
only  by  set  owners  but  by  manufacturers 
and  dealers.  Wonderful  as  radio  is, 
there  are  many  things  that  no  receiver 
can  be  guaranteed  to  accomplish. 

From  my  home  in  Chicago,  I  may  tune 
in  KGO,  San  Francisco,  with  loud 
speaker  volume,  every  night  during  a 
certain  week.  But  I  cannot  guarantee  to 
do  the  same  thing  the  next  week.  Neither 
can  I  guarantee  that  you  will  do  the  same 
thing  with  the  same  kind  of  a  set,  even 
though  your  home  may  be  nearer  San 
Francisco  than  Chicago  is.  This  will  not 
be  because  of  any  difference  between 
your  set  and  mine;  rather,  there  are 
several  factors  responsible  for  variation 
in  performance.  Here  are  three  of  the 
principal     ones: 

Practice  Helps 

First:  There  is  the  difference  between 
you  and  me.  I  am  not  bragging  about 
my  skill  as  a  tuner,  but  I  am  familiar 
with  my  own  set,  having  used  it  for  some 
time.      You   will   become  just   as   skilful 


in  tuning  your  set  after  you  have  used  it 
a  while. 

Second:  There  is  the  difference  in 
atmospheric  conditions — sometimes  a 
very  great  difference  between  two  suc- 
cessive nights.  No  one  can  ever  be 
certain  of  getting  a  particular  distant 
station  at  any  definite  time,  even  though 
that  station  is  known  to  be  broadcasting. 

Third:  There  is  the  difference  of 
locations.  Much  study  is  being  given 
to  this  perplexing  problem.  "Dead 
Spots"  are  known  to  exist — and  between 
"dead  spots"  and  the  ideal  location  is 
found  every  degree  of  conditions.  During 
experiments  made  in  Chicago,  a  set 
brought  in  a  certain  distant  station  when 
tuned  on  one  side  of  the  street,  but  when 
moved  to  the  other  side  of  the  street, 
that  station  could  not  be  heard  at  all. 

When  one  considers  these  facts,  it  is 
plain  that  no  set  manufacturer  can 
possibly  guarantee  the  distance  a  pur- 
chaser can  expect  from  the  set  he  buys. 

I  don't  want  you  to  get  the  idea  that 
there  is  any  probability  that  you  live 
in  a  "dead  spot"  where  the  pleasure  of 
a  radio  set  is  denied  you.  The  chances 
are  a  million  to  one  that  you  are  not. 
Although  receiving  conditions  may  not 
be  perfect  in  your  location,  you  can  still 
get  as  much  with  a  good  set  as  the 
average  radio  fan  is  getting.  Plainly, 
the  matter  of  atmospheric  conditions 
and  the  adaptability  of  your  location  to 
radio  reception  is  entirely  beyond  your 
(Turn  to  page  79) 


DEVICES 

-displaying  this  seal 
have  been  tested 
and  approved  by 
the  RADIO  AGE 
INSTITUTE. 

The  appara  tusillus- 
tr  a"  ted  and  des- 
cribed .  below  have 
successfully  passed 
our  tests  for  Jan- 
uary, 1925. 


Radio  Age  Institute 

Manufacturers'  Testing  Service 

AyfEMBERS  of  the  staff  of  RADIO  AGE  will  be  pleased  to  test  devices 
-*■*■*  and  materials  for  radio  manufacturers  with  the  object  of  deter- 
mining their  efficiency  and  worth.  All  apparatus  which  meets  with 
the  approval  of  various  tests  imposed  by  members  of  the  technical 
staff  of  RADIO  AGE  will  be  awarded  our  endorsement,  and  the  seal 
shown  to  the  left  will  be  furnished  free  of  charge.  Materials  for 
testing  should  be  sent  to 

RADIO  AGE  INSTITUTE 

504  N.  Dearborn  Street,  Chicago,  111. 


Test  No.  26.  MIDGET  LOUD- 
SPEAKER, known  as  the  "Reflec- 
tone."  Made  by  Rice  and  Hochster, 
of  130  Washington  Place.  N.  Y.  C. 
It  is  claimed  that  this  speaker  is 
the  smallest  loudspeaker  on  the 
market  today.  Notwithstanding 
its  small  size,  the  little  unit  gives 
tremendous  signals  with  surprising 
faithfulness  as  to  reproduction. 
Arrived  in  good  condition,  and 
satisfactorily  passed  the  tests  and 
requirements  of  the  RADIO  AGE 
Institute. 


Test  No.  27.  LOUDSPEAKER 
and  LAMP  COMBINED.  Better 
known  as  the  Radialamp.  Manu- 
factured bv  the  Radialamp  Co.. 
Dept.  810,  334  Fifth  Ave..  N.  Y.  C. 
The  lamp  is  a  beautiful  piece  of 
decorative  furniture  as  well  as  it  is 
exceptionally  fine  loudspeaker  for 
radio  use.  The  horn,  concealed  in 
the  stem  of  the  lamp,  throws  out 
its  mellow  sound  to  be  reflected  by 
the  new  sound  mirror,  a  new  idea 
in  accoustics.  The  lamp  was  received 
in  good  condition.  Tested  and 
approved  by  RADIO  AGE  Institute. 


Test  No.  28.  STORAGE  FILA- 
MENT BATTERY.  Made  by  the 
Philadelphia  Battery  Company,  Phil- 
adelphia, Pa.  These  batteries  are 
well  known  to  motorists  and  other 
electrical  people  as  "Philco"  Diamond 
Grid  batteries.  The  battery  has 
a  high  ampere  hour  rating,  good, 
sturdy  and  wear-resisting  plates 
and  separators.  The  battery  makes 
use  of  the  famous  principle  of  using 
the  Diamond  grid  formation  which 
it  is  claimed  is  superior  to  other 
types.  Arrived  in  excellent  con- 
dition, shipped  dry,  with  the  elec- 
trolyte in  a  separate  container. 
Tested  and  approved  by  the  RADIO 
AGE  Institute. 


Test  No.  29.  SEMI-F  I  X  E  D 
CONDENSER.  Better  known  as 
the  Build-Up  condenser,  made  by 
Chas.  Schindler  of  1404  W.  Dela- 
ware Ave..  Toledo,  Ohio.  A. useful 
instrument  in  dtermining  proper9 
capacities  for  fixed  condensers. 
The  unit  is  so  designed  that  plates 
may  be  added  or  removed  to  give 
any  capacity  from  .00025  to  .006 
mfds  This  steping  of  capacities 
is  accomplished  with  .0002  mfd. 
capacities  added  to  the  total  every 
time  a  plate  is  added.  The  mica 
is  high  grade,  and  the  case  is  fairly 
low  in  losses.  Tested  and  approved 
bv     the     RADIO    AGE     Institute. 


While  every  piece  of  apparatus  ad- 
vertised in  RADIO  AGE  must  be 
tested  and  approved  by  the  RADIO 
AGE  Institute  before  being  accepted, 
both  advertised  and  non-advertised 
apparatus  are  described  in  theRADIO 
AGE  Institute  department  on  this 
page.  Any  manufacturer  or  designer 
of  radio  sets  or  apparatus,  whether 
advertising  in  RADIO  AGE  or  not. 
may  sendhis  products  to  the  Insti- 
tute to  be  tested. 


*     Tested  and  Approved  by  RADIO  AGE     * 


78 


RADIO  AGE  for  January,   1924 


The  Magazine  of  the  Hour 


End  your  RadioTroubles  for  30c  in  Stamps 

We  have  laid  aside  a  limited  number  of  back  issues  of  RADIO  AGE  for  your  use.  Below  are  listed  hookups  to  be  found  in 
these  issues.  Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired.  The  supply  is  getting  low,  so  enrich  your 
store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 


May.  1922 

— How  to  make  a  simple  Crystal  Set  for  $6. 

September,  1922 

— How  to  make  a  Regenerative  Set  at  a  low  cost 

October,  1922 

— How  to  make  a  Tube  Unit  for  S23  to  S37. 
—How  to  make  an  Audio  Freauency  Amplifying  Trans- 
former. 

November,  1922 

— Design  of  a  portable  short-wave  radio  wavemeter. 

May,  1923 

— How  to  make  a  portable  Reinartz  set  for  3iimmer  use. 

June,  1923 

— How  to  build  the  new  Kaufman  receiver. 
— What  about  your  antenna? 

December,  1923 

— Building  the  Haynes  Receiver. 

— Combined  Amplifier  and  Loud  Speaker 

— A  selective  Crystal  Receiver. 

January,  1924 

— Tuning   Out  Interference — Wave   Traps — Eliminators 

—Filters. 

— A  Junior  Super-Heterodyne. 

— Push-Pull  Amplifier. 

— Rosenbloom  Circuit. 

RADIO  AGE,  Inc. 


— An  Eight-Tube  Super-Heterodyne. 
— A  simple,  low  loss  tuner. 
— A  Tuned  Radio  Frequency  Amplifier. 
— Simple  Reflex  Set. 

April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated). 
—A  Ten-Dollar  Receiver. 
— Anti-Body  Capacity  Hookups. 
— Reflexing  the  Three-Circuit  Tuner. 
— Index  and  first  two  installments  of  Radio  Age  Data 
Sheets. 

May,  1924 

— Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

— Important   Factors   in    Constructing   a   Super-Hetero- 
dyne. 
— A  Universal  Amplifier. 
— A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 
— Radio  Age  Data  Sheets. 


— A  Portable  Tuned  Impedance  Reflex. 
— Operating  Detector  Tube  by  Grid  Bias. 
—A  Three-Tube  Wizard  Circuit. 
— Data  Sheets. 


August,  1924 

— Breaking  Into  Radio  Without  a  Diagram 

— The  English  4-Element  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 

September,  1924 

— How  Careful  Mounting  Will  Improve  Reception. 
— One  Tuning  Control  for  Hair's  Breadth  Selectivity. 
— Four  Pages  of  Real  Blueprints    of  a    New  Baby    Hat* 

erodyne  and  an  Aperiodic  Variometer  Set. 
— Datasheets. 

October,  1924 

— An  Easily  Made  Super-Het. 
— Two  Radio  and  Two  Audio  for  Clear  Tone. 
— A  Simple  Regenerative  Set. 
—The  Ultradyne  for  Real  DX. 

— Real  Blueprints  of  a   3-Tube  Neutrodyne  and  a  Mid- 
get Reflex  Set. 

November,  1924 


Single  Tube  Loop  Set 


— Blueprii 

Feedback  Re- 
— A  3-Tube  Low  Los«<  Regenerator. 
—Mastering  the  3-Circuit  Tuner. 

December,  1924 

— Blueprints  of  a  New  8-Tube  Super-Heterodyne. 
— How  to  Make  a  Receiver  that  Minimizes  Static. 
—A  Trans-Ailantic  DX  Receiver. 

— How  to  Make  a  Home    Made   Battery  Cbarger   and  s 
Loud  Speaker  at  a  Small  Cost. 


500  N.  Dearborn  St.,  Chicago 


THE  RADIO  AGE  BUYERS'  SERVICE 


oltage) 


What  do  you  want 
Enter  the  number  of  the 

1  "A"  Batteries 

2  Aerial  protectors 

3  Aerial  insulators 

4  Aerials 

5  Aerials,  loop 

6  Amplifiers 

7  Amplifying  units 

8  Ammeters 

9  "B"  batteries 

10  Batteries   (state  \ 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery  substitutes 

17  Bezels 

18  Binding  posts 

19  Binding  posts,  insulated 

20  Books 

21  Boxe*,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatstone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisers 

33  Coils 

34  Coils,  choke 

35  Coils,  coupling 
3S  Coils,  filter 

37  Coils,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance 

40  Coils,   Reinartz 

41  Coils, 

42  Coils, 

43  Cond 

44  Cond 

45  Cond. 
ling 


to  purchase  in  the  radio  line? 
article  you  would  like  to  know 

57  Couplers,  loose 

58  Couplers,  molded 

59  Couplers,  vario 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 

71  Dial,  adjusters 

72  Dials,  composition 
hard  rubber 
rheostat 


Let  the  staff  of  RADIO   AGE   save   you 
more  about  in  the  spaces  provided  in  the 


time  and  money  by  sending  in  the  coupon  below, 
coupon. 


olded 


ulator 


ulators. 
ulators, 
ulators, 
-is.  sold 


high  v 
cloth 
glass 
hardr 

porcelaii 


dtage 


ubber 


*ith  kn. 
electric 


iser  parts 
lsers,  antenn 


pho 


46  C 

47  Conden 

48  Conden 

49  Cond 
grid, 

50  Condensers,  varii 

51  Condensers,  varii 

52  Condensers,  vern 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  s 


by-pass 

coupling 

filter 

fixed  (paper, 


73  Die 

74  Dials, 

75  Dials, 

76  Dials. 

77  Dials 

78  Dies 

79  Drills 

80  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

83  Enamels,  battery 

84  Enamels,  metal 

85  End  stops 

86  Eyelets 

87  Experimental  work 

88  Fibre  sheet,  vulcanized 

89  Filter  reactors 

90  Fixtures 

91  Fuse  cut  outs 

92  Fuses,  tube 

93  Generators,  high  frequ 
cy 

94  Grid  choppers,  rotary 

95  Grid  leak  holders 

96  Grid,  transmitting  leal 

97  Grid  leaks,  tube 

98  Grid  leaks,  variable 

99  Grinders,  electric 

100  Ground  clamps 

101  Ground  rods 

102  Handles,  switch 

103  Head  bands 

104  Head  phones 

105  Head  sets 

106  Honeycomb  < 

107  Hook  ups 

108  Hon 


>il  adapte 


109  Hor 

110  Horn 

111  Horn 

112  Horn 

113  Hydr. 


,  fibr. 


114  Indicators,  polarity 

115  Inductances,  C.  W. 

116  Insula   ' 

117  Insula 

118  Insula 

119  In 

120  In 

121  In 

122  In 

123  In 

124  In 

125  In 

126  lr. 

127  Jacks 

128  Filament  control 

129  Jars,  battery 

130  Keys,  transmitting 

131  Knobs 

132  Knock-down  panel  units 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arresters 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  units 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instruments 

142  Megohmeters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeters 

148  Minerals 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,      condenser 
leak 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,  honeycomb 
coil 

156  Mountings,     inductance 
switch 

157  Name  plates 

158  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeters 

161  Oscillators 

162  Panel  cutting  and  drilHn 

163  Panels,      drilled     and     ur 
drilled 

164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  soldering 


Patent  attorneys 
Phone  connectors, 
pie 
Phonograph  adapl 

Plates, 


Plu 


til 


172 

173  Plugs,  telepho 

174  r 
175 
176  : 


178  ; 

179  1 

180  I 


pote 


int; 


Resistance  leaks 

Rheostat  bases 
Rheostat 
Rheostat 
Rheostat 
Rheostat 
Rheostat 
Rheostat; 
Rheostats,  powe 
Rheostats,  ve 
Rods,  ground 
Rotors 

Scrapers,  wire- 
Screw  drivers 
Screws 
Sch( 
Set* 
Sets 

Sets,  receiving- 
trod  yne 

Sets,  receiving — 
Sets,  receiving — 
quency 

Sets,  receiving- 
Sets,  receiving— 
tive 

Sets,    receiving— 
Sets,  receiving — - 
Sets,  receiving—: 
Sets,     receiving- 
generative 
Sets,  transmittir 
Slate 
Shellac 
Sliders 

Socket  adapters 
Sockets. 
Solder 

Soldering  irons. 
Soldering  paste 
Solder  flux 


221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 

226  Stampings 

227  Stators 

228  Stop  point* 

229  Switch  arms 

230  Switch  levers 

231  Switch  points 

232  Switch  stops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switches,  ground 

237  Switches,  inductance 

238  Switches,  panel 

239  Switches,  single  and  dou- 
ble throw 

240  Tone  wheels 

241  Towers,  aerial 

242  Transformers,     audio     fre- 
quency 

243  Transformers,  filament 

244  Transformers,  modulation 

245  Transformers,  power 

246  Transformers,  push-pull 

247  Transformers,     radio     fre- 
quency 

248  Transformers,  variable 

249  Transmitters 

250  Tubes,  vaccuum — peanut 

251  Tubes,    vacuum — two    ele— 

252  Tubes,  vacuum — three  ele- 
ment 

253  Tuners 

254  Variocou piers,  hard  rubber 

255  Vario  couplers,  molded 


regenera- 


256  Vi 

257  Va 

258  Va 

259  Va 

260  V. 


261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 


piers,  woode: 
meters,  hard  rubber 
meters,  molded 
meters,  wooden 
ih,  insulating 


,  braided  and  strand- 
copper 
.  insulated 
,  Li tz 
,  magnet 


267  Wir 

268  Wir 

269  Wir 

270  Wir 

271  Wir. 

272  Wire,  tungsten 


RADIO   AGE   BUYERS'  SERVICE,  500   N.  Dearborn   St.,   Chicago,  111. 

Please    see   that   I    am    supplied  with    buying   specifications    and    prices   on    the    a 

rticles  numbered  herewith: 

1        1        1        1        1        1        1        1        1        1 

1               1               1                1 

1 

I  am  a—  Q  Dealer                 Q   Jobber                [H    Mfers.'   Kep. 

□    Manufacturer 

j 

I 


RADIO  AGE  for  Jqnuary,  1925 


The  Magazine  of  the  Hour 


79 


(Continued  from  page  77) 
control.      But    there    is    the    first    point 
mentioned     above — individual     skill     in 
tuning,  that  you  can  control. 

How  Much  Skill? 

The  question  is  "How  much  does  skill 
in  tuning  have  to  do  with  the  results 
you  will  get  from  your  set?"  Let  me 
relate  a  few  of  my  experiences: 

I  have  had  several  people  come  to  my 
house,  some  of  whom  have  never  operated 
a  radio  set,  and  others  who  have  used 
regenerative  sets  of  various  types.  I 
explained  to  them  briefly  how  to  tune 
my  set,  and  watched  them  work.  Of 
course,  they  had  no  trouble  in  tuning 
local  stations.  Even  Pittsburgh,  Sche- 
nectady and  Springfield  came  in  pretty 
strong,  and  they  got  them  without  much 
trouble.  Then  I  asked  them  to  fish 
around  for  other  distant  stations  and 
watched  them  very  closely.  Invariably 
they  would  pass  by  several  stations  with- 
out bringing  them  in  at  all.  I  then  tuned 
in  four  or  five  of  these  stations  which 
they  had  missed.  I  showed  them  how 
the  difference  of  one-half  a  division  on 
the  dials  would  often  make  the  difference 
in  bringing  in  the  station  on  the  loud 
speaker  or  missing  it  altogether. 

I  have  visited  a  number  of  people  in 
my  neighborhood  who  have  been  using 
sets  like  mine — some  for  several  weeks 
and  others  for  only  a  few  days.  One 
very  intelligent  man,  who  had  discarded 
a  well-known  regenerative  receiver  three 
weeks  before,  told  me  that  it  took  him 
two  weeks  to  realize  how  sharp  his  new 
set  tuned.  He  said,  "I  can  now  get 
most  anything  I  want,  but  I  couldn't  get 
much  more  than  local  stations  the  first 
week."  The  thing  that  fooled  him  at 
first  was  the  absolute  quietness  of  the 
new  set,  unless  all  three  dials  were  tuned 
exactly  to  the  same  wavelength. 

Here  is  another  thought  I  want  to 
leave  with  you.  In  tuning  for  distant 
stations,  except  the  very  powerful  ones, 
I  generally  use  the  head  set.  Because 
of  the  extreme  selectivity  of  some  sets, 
even  the  most  skilled  tuner  will  often 
pass  by  a  distant  station  if  tuning  with 
a  loud  speaker.  This  naturally  brings 
up  another  question:  "When  I  have 
tuned  in  a  distant  station  on  a  head  set, 
can  I  always  put  it  on  the  loud  speaker 
with  satisfactory  volume?" 

Not  by  any  means.  Often  the  signal 
is  so  weak,  due  to  causes  entirely  outside 
of  the  receiver,  that  head-phone  volume 
is  all  I  can  get.  Particularly,  this  is 
true  during  the  day  time  and  in  seasons 
except  cold,  snappy  Winter  weather. 

Some  day  these  things  may  be  over- 
come, but  I  prophesy  that  the  change 
will  come  through  improvement  in  broad- 
casting stations  rather  than  receiving  sets. 
Until  that  time  comes,  I  am  going  to 
continue  getting  a  lot  of  fun  out  of  what 
I  can  do  and  not  fret  about  what  I  can't 


REFLEX 

Erla  —  Acme  —  Harkness 

Dealers:    Send  for  Discounts 

HUD50N-R0JS 

123  W.  Madison  St.  Chicago 


do.     Here  is  the  way  I  size  up  the  matter: 
What  to  Look  For 

There  are  four  qualifications  to  look 
for  in  a  radio  set: 

1.  Quality  of  Reception. 

2.  Selectivity. 

3.  Volume. 

4.  Distance. 

The  first  is  absolutely  essential.  11 
your  set  fails  to  give  clear,  undistorted 
music,  then  it  doesn't  make  any  differ- 
ence how  selective  it  may  be  or  what 
volume  and  distance  it  will  give  you; 
without  good  music  it  is  worthless. 

Greater  progress  has  been  made  this 
year  in  improving  quality  of  reception 
than  in  the  four  or  five  years  previous. 
Radio  can  now  give  a  quality  of  music 
superior  to  anything  that  the  phonograph 
has  ever  done. 

The  matter  of  selectivity  is  of  greater 
or  less  importance,  depending  entirely 
upon  where  you  live.  If  you  are  located 
in  or  near  a  big  city  where  there  are 
several  powerful  local  broadcast  stations, 
you  must  have  a  selective  set  if  you 
expect  to  get  through  local  stations  and 
bring  in  distant  ones. 

It  is  no  great  feat  to  separate  two 
stations  5  to  10  meters  apart  in  wave- 
length, when  both  stations  are  several 
hundred  miles  distant.  But  it  does  take 
a  very  selective  receiver  to  bring  in  a 
distant  station  if  it  is  within  10  to  20 
meters  of  a  local  station. 

Volume  is  important  only  to  the  degree 
that  it  enables  you  to  put  the  stations 
you  want  to  hear  on  the  loud  speaker. 
By  loud  speaker  volume,  I  have  in  mind 
music  that  will  fill  the  room  and  prove 
enjoyable  to  the  listeners.  Sometimes 
when  conditions  are  just  right,  I  can 
bring  in  a  station  1500  miles  away  so 
strong  it  can  be  heard  all  over  the  house. 
But  I  don't  do  it.  Music  so  loud  as  that 
is  anything  but  agreeable  to  persons  in 
the  same  room  with  the  loud  speaker. 

Distance  I  consider  the  least  important 
of  all. 

I  know  that  my  set  will  get  distance 
enough  to  bring  in  the  powerful  stations 
from  one  coast  to  another.  I  hear  men 
brag  of  getting  little  one-horse  stations 
in  Canada  or  California,  but  that  doesn't 
mean  anything  to  me.  I  look  upon 
radio  as  a  source  of  music  and  pleasure 
in  my  home.  I  don't  consider  it  a  game 
of  seeing  how  many  stations  you  can  log. 

I  know  that  the  best  programs  come 
from  the  powerful  stations.  It  doesn't 
worry  me  at  all  if  I  don't  get  little  sta- 
tions I  never  even  heard  of,  because  I 
know  they  are  not  putting  out  programs 
I  would  care  to  hear. 

There  is  no  doubt  in  my  mind  that  some 
day  radio  is  going  to  be  improved  far 
beyond  the  comparative  perfection  of 
today,  but  I  have  very  little  patience 
with  a  man  who  says,  "I  am  going  to 
wait  to  buy  my  radio  set  until  radio  is 
perfected."      It    is    perfected    right  now. 


MAKE  YOUR  RECEIVING 
SET  SELECTIVE 


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DAVENPORT  RADIO 
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RADIO  AGE  for  January,   1925 


The  Magazine  of  the  Hour 


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Please  send  RADIO  AGE,  the  Magazine  of  the  Hour,  to  the  following  for  one  year, 
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— the  Pfanstiehl  Model  7  Receiver 

cA5-tube  Receiver  using  the  new  system  of  tuned  radio  frequency 


RADIO  is  no  longer  a  scientific  toy,  something  to  play 
-  with.  Like  the  telephone,  the  piano,  and  the  phono- 
graph, it  has  become  a  modern  home  convenience.  The 
chief  use  of  radio  today  is  that  of  an  instrument  of  com- 
munication and  entertainment.  Hence.whatpeoplewant 
in  a  receiver  is  trouble-proof  service.  That  means  a  sim- 
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natural. 

A  Non-Oscillating  System 

What  Pfanstiehl  has  done  has  been  to  design  the  sim- 
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need  of  choking  or  neutralizing  devices.  The  absence  of 
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sweetness.  Speech  and  music  are  naturally  received, 
naturally  reproduced.  Distance  makes  no  difference. 
There  is  no  distortion  however  great  the  amplification. 
And  tuning  is  so  sharp  that  wave  lengths  can  be  received 
distinctly  and  separately  less  than  8  meters  apart. 

See  and  hear  this  new  system  that  is  revolutionizing 
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Crosley  One  Tube 
Model  50,  $14.50 

With  tube  and  Crosley  Phone.  $22 


Better -Costs  Less 
Radio 

OH,  boy!  There's  the  West  Coast!  Last  night  I  had  the  East  Coast, 
and  the  night  before  that,  Havana.  I  bet  I  get  London  soon. 
This  Crosley  sure  does  bring  'em  in.  I  can  tune  out  local  stations  any 
old  time  and  get  what  I  want.     There's  nothing  like  a  Crosley!" 

That's  what  thousands  of  men,  women  and  boys  are  finding  out 
every  evening  in  all  parts  of  the  United  States.  So  enthusiastic 
are  they  that  hundreds  of  voluntary  letters  tell  us  daily  of  the  really 
remarkable  performances  of  Crosley  Radios  and  the  complete  satis- 
faction that  they  give.     Here  is  what  a  few  of  them  say: 

Parkersburg,  W.  Va.  September  30,  1924. 

"Wish  to  congratulate  you  on  the  one-tube  Crosley  50.  Have 
listened  to  Havana,  Cuba,  and  as  far  west  as  Oakland,  Los  Angeles 
and  San  Francisco.     This  is  what  I  call  a  wonderful  set." 

Rockville,  Maryland.  October  1,  1924. 

"I  thought  it  would  interest  you  to  know  that  on  September  15th, 
I  received  Oakland,  California,  on  my  two-tube  Crosley  51.  That 
station  is  2,434  miles  from  here.  I  had  a  hard  time  making  my 
friends  believe  it  until  I  wrote  to  California  and  had  them  verify 
what  I  heard.     As  soon  as  I  can  afford  it,  I  expect  to  get  aTrirdyn." 

Olney,  Illinois.  October  15,  1924. 

"I'm   getting   stations  from   New   York   to   Seattle,    Wash.,    on   my 
Trirdyn.      Monday  night,  October  13th,  I  received  clearly  and  plainly 
the  announcer  and  music  from  Honolulu,  Hawaiian  Islands,  7,000 
miles  away.     My  machine  is  not  for  sale." 
( Names  upon  request) 

BEFORE  YOU  BUY— COMPARE 

YOUR  CHOICE  WILL  BE  A  CROSLEY 

For  Sale  By  Good  Dealers  Everywhere 

Crosley  Regenerative  Receivers  are  Licensed  under  Armstrong  U.  S.  Patent  1,113,149 
Prices  West  of  the  Rockies  add  10% 

Write  for  Complete  Catalog 

THE  CROSLEY  RADIO  CORPORATION 

Powel  Crosley,  Jr.,  President 
163  Alfred  Street  Cincinnati,  Ohio 

Crosley  Owns  and  Operates  Broadcasting  Station  WLW 

*     Tested  and  Approved  by  RADIO  AGE 


Crosley 

Head  Phones 

Better — Cost  Less 

$3.75 


Crosley  Two  Tube  Model  51,  $18.50 

With  tubes  and  Crosley  Pbor.es  $30.25 


Crosley  Three  Tube  Model  52,  $30.00 
With  tubes  and  Crosley  Pbones  $45.75 


Mail 

Thit 

Coupon 

At  Once 

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Radio  Corpn. 
163  Alfred  St. 
Cincinnati,  O. 
Mail  me,  free  of 
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of  Crosley  receivers 
d   parts. 


Crosley  Trirdyn  Special,  $75.00 

With  tubes  and  Crosley  Pbones  $90.75 


Address. 


In  This  Issue: 

Is  There  a  Radio 
Trust? 


IFEBRUmRY 

MEET  YOUR  BROADCAST  FAVOPJT I 


Super-  Zenith  VII — 

the  ideal  radio  set 

for  the  fine  home 


They  Cost  More 

But  They  Do  More 


Super- 
Zenith  X 


Fulfills  your  utmost  desire, 
in  beauty  and  performance 

The  new  Super-Zenith  is  beautiful  to  look  at — lends  an  atmos- 
phere of  dignity  and  worth  to  library  or  drawing  room. 
Naturally  you  expect  unusual  performance  from  so  beautiful  a 
radio  set.  And  —  unusual  performance  is  exactly  what  you  get. 
Tuning,  for  example,  is  controlled  by  two  dials  only — so  per- 
fectly adjusted  that  each  station  comes  in  always  at  the  same 
dial  settings.  It  never  varies.  Powerful  locals  may  be  on  full 
blast,  yet  you  can  tune  them  out  completely  and  bring  in  distant 
stations.  Tone  reproduction  is  always  clear  and  true;  the  volume 
always  adequate. 

Before  you  make  your  choice,  be  sure  to  see  and  try  the  new  Super- 
Zenith.  A  fifteen-minute  test  will  give  you  a  new  standard  of  radio 
values,  as  applied  to  beauty  of  construction— and— performance. 

Dealers  and  Jobbers:  Write  or  wire  for  our  exclusive  territorial  franchise 

ZENITH  RADIO  CORPORATION 

332  South  Michigan  Avenue,  Chicago 

ZENITH— the  exclusive  choice  of  MacMillan  for  his  North  Pole  Expedition 

Holder  of  the  Berengaria  Record 


===== 

ft   /"T>HE  complete  Zenith  line  ln- 
r       X  eludes  seven  models, ranging 
in  price  from  $95  to  $550. 

With  either  Zenith  3R  or  Zenith 
4R,  satisfactory  reception  over 
distances  of  2,000  to  3,000  miles 
is  readily  accomplished,  using 
any  ordinary  loud  speaker. 
Models  3R  and  4R  licensed  under 
ArmstrongU.S.Pat.No.l, 113,149. 


The  new  Super-Zenith  is  a  six- 
tube  set  with  a  new,  unique, 
and  really  different  patented 
circuit,  controlled  exclusively  by 
the  Zenith  Radio  Corporation. 
It  is  NOT  regenerative. 


:nent.     V" 


SUPER-ZENITH  VII— Six  tubes  — 2  stages  tuned 
frequency  amplification— detector  and  3  stages  audio 
frequency  amplification.  Installed  in  a  beautifully 
finished  cabinet  of  solid  mahogany  —  44>s  inches 
long,  16%  inches  wide,  10  H  inches  high.  Compart- 
ments at  either  end  for  dry  batteries.  Price  (h'7'^/^ 
(exclusive  of  tubes  and  batteries)     ....  ^Jv 


SUPER-ZENITH  VIII—  Same  as  VII  except— console 
type.  Price  (exclusive  of  tubes  and  bat-  <£.--)  r-r\ 
teries) i$Zj\J 


SUPER-ZENITH  IX, -Console  model  with  addi- 
tional compartments  containing  built-in  Zenith  loud 
speaker  and  generous  storagebattery  space.  (b'J  £r\ 
Price  (exclusive  of  tubes  and  batteries)    .    .  <P-'-J^f 


impossible  with  single-unit  speakers.  2nd 
Battery  Eliminator,  distinctly  a  Zenith  achievemen 
Requires  no  A   or  B  batteries  a--* 

Price  (exclusive  of  tubes) Ip330 

Price   (without  battery  eliminator)     ....     $450 
All  Prices  F.  O.  B.  Factory. 


Zenith  Radio  Corporation 

Dept.2C 

332  South  Michigan  Avenue,  Chicago,  III. 

Gentlemen:   Please  send  me  illustrated  literature 
giving  full  details  of  the  Super-Zenith. 


SUPER-ZENITH  X— Contains  two  new  features 
superseding  all  receivers.  1st— Built  in,  patented, 
Super-Zenith  Duo-Loud  Speakers  (harmonically 
synchronized  twin  speakers  and  horns) .  designed  to 
reproduce  both  high  and  low  pitch  tones  otherwise 


Address 


J 


*      Tested  and  Approved   by   RADIO   AGE      * 


RADIO  AGE>r  February,  1925 


The  Magazine  of  the  Hour 


I  Can  Qualify  You 

as  a  Radio ExpertmSm- 
in  a  Few  Months! 


i 


'Earn  $2500  to  $10,000  a  Year 


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aging $70  a  week  in  a  radio 
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E.  R.  HAAS 

Director,    National 
Radio  Institute 


Hundreds  of  Big  faymg  Positions  Waiting- 


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Grand  Juntion.  Colo. 


From  $15  to  $80  a  Week 


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(Signed)    Geo.   A.    Adams, 
Tamao.ua,  Pa. 


This  Wonderful  FREE  BOOK 
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NATIONAL  RADIO  INSTITUTE 

Dept,  53DB  Washington,  D.  C. 


E.  R.  HAAS 

NATIONAL    RADIO     INSTITUTE 
Dept.  53DB,  Washington,  D.  C. 

Without  obligation  on  my  part,  please 
send  me  the  free  book  "Rich  Rewards  in 
Radio."  with  full  details  as  to  how  I  can 
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Street. _ 


City- 


State.. 


—  J 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hoi 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITH  WHICH  IS  COMBINED  RADIO  TOPICS 


Volume  4 


February,  1925 


Number  2 


CONTENTS 

Radio   Editorials — Is  there  A  Radio  Trust? 4 

A  Sure  Shot  Super-Heterodyne 9 

By  Arthur  B.  McCullah 

A  Three-Circuit  Regenerator.. 13 

By  Brainard  Foote 

A  Radio  Cross-Word  Puzzle 16 

By  John  B.  Rathbun 

A  Unit  for  Measuring  Capacity. _ 17 

By  H.  Frank  Hopkins 

How  About  Your  Antenna? 20 

By  Armstrong  Perry 

The  How  and  Why  of  Vacuum  Tubes 21 

By  Frank  D.  Pearne 

A  Low  Loss  Set  that  Spells  "DX" 23 

By  Ray  G.  Piety 

Up  the  Ladder  with  the  Radio  Beginner 26 

By  Edmund  H.  Eitel 

Reflexing  a  Single  Circuit  Set 28 

By  C.  H.  Dillon 

"The  Hidden  Voice:"  Final  Instalment 29 

By  Frank  Honeywell 

"What    the    Broadcasters    are    Doing" — RADIO 

:  AGE    Studio-Land    Feature    Section 30 

RADIO  AGE  BLUEPRINT  SECTION 

A  Three  Tube  Reflex  Set... 39 

By  John  B.  Rathbun 

Pickups  and  Hookups  by  Our  Readers 49 


Radio  Age  Is  published  monthly  by  RADIO  ACE,   Inc. 
Member:     Audit  Bureau  of  Circulations. 


Executive,  Editorial  and  Advertising  Offices 
500  N.  Dearborn  Street,  Chicago,  111. 
Publication  Office,   Mount   Morris,   111. 

Frederick  A.  Smith,  Editor 
Russell  H,  Hopkins,  Associate  Editor 
Frank  D.  Pearne,  Technical  Editor 
C.  H.  Dillon,  Technical  Assistant 
Louis  L.  Levy,  Circulation  Manager 
M.  B.  Smith,  Business  Manager 

Advertising  Director 
HARRY  A.  ACKERBURG 


Eastern  Representative 
DAVIDSON  &  HEVEY,  17  West  42nd  St.,  New  York  City 

Pacific  Coast  Representative 
BENJAMIN  LEVEN,  582  Market  St.,  San  Francisco. 

Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 
preceding  date  of  issue 
Issued  monthly.  Vol.  4,  No.  2.  Subscription  price,  $2.50  a  year. 

Entered  as  second-class  matter  October  2,  1924,  at  post  office  at  Mount  Morris, 
Illinois,  under  the  Act  of  March  3,  1879. 


Copyright.  n>25.  bu  RADIO  AGE.  /no. 


A  Chat  With 
the  Editor 

READERS  have  been  quick  to 
understand  the  insidious  sig- 
nificance of  the  effort  of  Radio 
Corporation  of  America  to  prevent 
the  registration  of  the  title  of  this 
magazine  in  the  Patent  Office  in 
Washington. 

Radio  Corporation  confesses  it 
controls  "Wireless  Age"  and  objects 
to  our  use  of  the  name  RADIO  AGE 
on  the  ground  that  "Wireless  Age" 
is  likely  to  be  injured  thereby. 

Radio  Corporation  did  not  make  the 
claim  until  RADIO  AGE  had  been 
flourishing  for  more  than  forty-one 
months,  building  up  its  name  and 
good  will  throughout  the  United 
States,  Canada  and  England. 

Many  readers  have  written  us 
letters  wishing  us  well  in  this  strange 
contest  between  our  independent 
magazine,  capitalized  at  $5,000,  and 
a  Corporation  capitalized  at  $33  - 
000,000. 

These  letters  not  only  have  brought 
encouragement,  but  they  have  laid 
bare  facts  about  Radio  Corporation 
that  were  new  to  us;  and  we  thought 
we  were  well  informed.  We  invite 
more  letters  on  the  subject. 

Counsel  has  been  engaged  and 
RADIO  AGE  will  take  its  case  to 
the  Patent  Office  and  fight  it  out. 
Our  formal  reply  to  Radio  Corpora- 
tion is  being  presented  in  Washington 
as  we  go  to  press. 

We  do  not  believe  that  Radio  Cor- 
poration always  can  have  what  it 
wants  when  it  wants  it.  If  you  are 
interested,  you  may  watch  our  maga- 
zine for  news  of  developments  from 
month  to  month.  Money  talks.  So 
do  printing  presses. 

Editor  of  RADIO  AGE. 


It  may  interest  our  readers  to  know 
that  Arthur  B.  McCullah,  whose  arti- 
cle on  a  "sure  shot"  Super-het  appears 
in  this  issue,  will  contribute  regularly 
to  RADIO  AGE  beginning  next 
month.  Watch  for  one  of  his  best 
articles  in  the  March  RADIO  AGE, 
fully  illustrated.  Also,  a  lineup  of 
other  technical  experts  will  be  on  hand 
with  their  latest  offerings. 


RADIO  AGE  for  February,   1925 

f 


TJie  Magazine  of  the  Hour  3 


No.  770.  45-jnj« 
extra  large  ver- 
tical. For  heavy 
duty  only.  The 
ideal  "B"  Bat- 
tery for  use  on 
multi-tube  sets. 
Price  $4.75. 


Scientists  constantly  improve  battery  quality 


Eveready  "B"  Batteries  today  contain  more 
electricity,  more  service,  more  satisfaction  than 
ever  before. 

Processes  evolved  by  the  scientists  of  the  Union 
Carbide  and  Carbon  Research  Laboratories,  Inc., 
when  put  in  effect  in  the  Eveready  factories,  are 
responsible  for  this  great  accomplishment. 

At  the  same  time  the  factories  have  effected 
a  still  higher  standard  of  workmanship.  A  system 
of  inspection  that  is  a  marvel  of  efficiency  was 
inaugurated.  The  results,  gratifying  beyond 
measure,  were  accomplished  with  a  speed  and 
completeness  that  have  few  parallels  in  industry. 


The  final  tests  showed  more  electricity,  more  bat- 
tery service,  greater  Eveready  satisfaction  with- 
out increasing  battery  sizes  and  with  a  substantial 
reduction  in  price.  "JB"  Battery  operating  costs, 
using  the  new  Evereadys,  in  most  cases  show  a 
reduction  of  at  least  one-half. 

There  is  an  Eveready  Radio  Battery  for  every 
radio  use. 

Insist  on  Eveready  "B"  Batteries. 

Manufactured  and  guaranteed  by 

NATIONAL  CARBON  COMPANY,  Inc. 

Headquarters  for  Radio  Battery  Information 

New  York  San  Francisco 

Canadian  National  Carbon  Co.,  Limited,  Toronto,  Ontario 


EVEREADY  HOUR 
EVERY  TUESDAY  at  9  P.  M. 

(Eastern  Standard  Time) 

Broadcast  through  a  chain  of  prominent 

interconnected  radio  stations. 


they  last  longer 


*     Tested  and  Approved  by  RADIO  AGE     ¥ 


RADIO  AGE  for  February,  192< 


The  Magazine  of  the  Hour 


Is  There  A  Radio  Trust? 


INASMUCH  as  we  have  an  anti-trust  law  in  the 
United  States,  and  inasmuch  as  the  radio  industry 
has  reached  huge  proportions,  it  is  interesting  and 
important  to  consider  the  question  as  to  whether  there 
is  a  radio  trust.  If  there  is  such  a  combine,  it  is  quite 
natural  that  law-abiding  Americans  generally  and 
radio  manufacturers,  dealers  and  buyers  of  radio 
goods  amounting  to  $350,000,000  annually  in  par- 
ticular should  desire  to  smash  it. 

It  is  the  business  of  the  Federal  Trade  commission, 
created  by  Act  of  Congress,  Sept.  26,  1914,  to  seek  out 
trusts.  The  Commission  issued  a  complaint  against 
eight  great  companies  on  January  26,  1924,  charging 
that  they  "have  been  and  are  using  unfair  methods 
of  competition  in  commerce." 

All  the  companies  named  in  the  complaint  are  con- 
cerned in  either  the  radio  or  the  wireless  business  and 
they  are  called  upon  to  appear  and  "show  why  an 
order  should  not  be  entered  by  said  commission  re- 
quiring you  to  Cease  and  Desist  from  the  violation  of 
the  law  charged  in  this  complaint." 
The  companies  named  are: 

General  Electric  Company 

American  Telephone  and  Telegraph  Company 

Western  Electric  Company,  Inc. 

Westinghouse  Electric  &  Manufacturing  Company 

The  International  Radio  Telegraph  Company 

United  Fruit  Company 

Wireless  Specialty  Company 

Radio  Corporation  of  America. 
The  complaint  occupies  fourteen  closely  typewritten 
pages  of  radio  history  that  should  be  intensely  inter- 
esting to  every  set-builder  or  vacuum  tube  buyer.  That 
means  to  20,000,000  citizens.  All  the  companies 
accused  have  made  replies  to  the  complaint,  denying 
portions  of  it,  admitting  other  'portions,  expressing 
ignorance  about  others,  asking  for  more  facts  on  others 
and  offering  an  ensemble  of  legal  verbiage  that  would 
give  a  Philadelphia  lawyer  a  long  pause. 

Radio  Corporation  is  organized  under  the  laws  of 
the  State  of  Delaware  and  was  incorporated  in  October, 
1919,  with  its  principal  place  of  business  in  New  York 
City.  Its  capitalization  is  5,000,000  shares  preferred 
stock,  par  value  $5.00  and  5,000,000  shares  of  common 
stock  no  par  value. 

Radio  Corporation  is  engaged  in  conducting  com- 
munication service  by  wireless  between  points  in  differ- 
ent states  in  this  Country  and  between  ships  and  shore 
and  with  foreign  countries.  It  is  also  engaged  in  the 
business  of  buying  and  selling  apparatus  and  devices 
for  use  in  radio  broadcasting  and  receiving  and  in  radio 
communication,  and  shipping  such  apparatus  in  inter- 
state commerce  and  to  foreign  countries. 

In  the  month  following  its  incorporation,  Radio 
Corporation  purchased  the  patents,  physical  assets 
and  stock  owned  or  controlled  by  the  Marconi  Wireless 
Telegraph  Company.  At  the  same  time  the  General 
Electric  Company  purchased  the  British  holdings  of 
the  Marconi  stock  in  America.  The  Marconi  Wireless 
Telegraph  Company  of  America  was  then  dissolved. 
For  its  services  the  General  Electric  Company  was 
given  135,174  shares  of  preferred  and  2,000,000  of  the 


common  stock  of  Radio  Corporation.  The  General 
Electric  Company  then  granted  to  Radio  Corporation 
license  to  use  apparatus  for  radio  purposes  under  all 
patents  present  or  future,  owned  by  the  General  Elec- 
tric Company,  the  exclusive  right  to  make  and  sell 
radio  devices  through  Radio  Corporation  only.  Radio 
Corporation  agreed  to  generally  restrict  its  business 
to  radio  supplies  and  not  to  enter  into  competition 
with  the  General  Electric  Company  with  any  patented 
device,  process  or  system,  or  encourage  others  to  do  so. 
All  the  foregoing  is  alleged  by  the  Federal  Trade  Com- 
mission with  the  additional  information  that  "The 
General  Electric  Company  is  the  largest  manufacturer 
of  Electrical  apparatus,  including  devices  used  in  radio 
communication,  in  the  United  States." 

In  June,  1920,  the  Westinghouse  Electric  and  Manu- 
facturing Company  received  from  the  International 
Radio  Telegraph  Company  assignment  of  the  Inter- 
national Company's  patents,  with  agreement  as  to 
mutual  exclusive  right  to  make,  use  and  sell  apparatus 
controlled  by  these  patents.  So  says  the  Federal 
Trade  Commission  and  further  alleges  that  the  West- 
inghouse Company  was  to  sell  all  its  products  under 
these  patents  to  the  International  Company  and  the 
International  Company  agreed  not  to  enter  under  any 
patent  rights  into  the  field  of  the  Westinghouse  Com- 
pany. On  Dec.  31,  1922,  the  Westinghouse  Company 
owned  1,000,000  shares  of  the  common  and  1,000,000 
of  the  preferred  stock  of  Radio  Corporation. 

In  July,  1920,  says  the  Federal  Trade  Commission, 
an  agreement  as  to  patents  was  made  among  the 
General  Electric  Company,  The  American  Telephone 
and  Telegraph  Company,  Radio  Corporation  of  Amer- 
ica and  The  Western  Electric  Company. 

In  March,  1921,  Radio  Corporation  made  an  agree- 
ment with  the  United  Fruit  Company  affecting  patents 
and  wireless  communications.  This  agreement  in- 
volved also  the  products  of  the  Wireless  Specialty 
Apparatus  Company.  On  December  31,  1922,  the 
United  Fruit  Company  owned  160,000  shares  of  the 
common  and  200,000  shares  of  the  preferred  stock  of 
the  Radio  Corporation  of  America.  It  is  alleged  by 
the  Federal  Trade  Commission  that  Radio  Corporation 
made  an  agreement  with  the  Wireless  Specialty  to 
permit  that  Company  to  make  certain  apparatus 
under  patent  license  of  Radio  Corporation,  but  the 
Wireless  Specialty  Apparatus  Company  was  specifi- 
cally not  permitted  to  make  vacuum  tubes. 

Other  agreements  as  to  exclusive  rights  were  made 
by  the  Radio  Corporation  with  various  companies 
interested  in  wireless  communications. 

The  Federal  Trade  Commission  outlines  the  new 
famous  "Patent  license"  policy  of  Radio  Corporation 
to  offer  "just  one  more  obstacle  that  non-licensees  will 
have  to  overcome."  It  is  alleged  by  the  Federal  Trade 
commission  that  the  details  of  the  transactions  sketched 
briefly  in  the  foregoing  show  that  "the  respondents 
have  combined  and  conspired  for  the  purpose  and 
with  the  effect  of  restraining  competition  and  creating 
a  monopoly  in  the  manufacture  and  purchase  and  sale  in 
inter-state  commerce  of  radio  devices  and  apparatus." 
(Turn  to  page  62) 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour  5 


in  i  mini  ii  n  nun  minium  n in  in  mil hum iiiiiiiniiiiiiiiiiiin  .imimii urn iiiiniii: 


The  Largest  Selling  Thmsfbrrrww inffie^rld [;\ 


T^uiim  in  ii  ii  i  mi  i  ii  n  i  ii  in  iiiiii  in  ii  i  ii  I  ii  ii  in  in  i  m  ii  imii mmimiiiiir 


Other 

Guaranteed 
Radio  Products 

Power  Amplifying 
Transformers 

(Push-Pull) 

Input  TvpeR-30  $6.00 
'Output  Type  R-31  6.00 

Rauland-Lyric 

A  laboratory  grade  audio 
transformer  for  music! 
lovers.    R-500 $9.00" 


Universal  Coupler 

Antenna  coupler  or 
tuned  r.  f.  transfor- 
mer. R-140 $4.00 


Reliable  / 


All' American  Standard  Audio  Frequency  Transformers  in  any 
radio  receiving  set  mean  but  one  thing- — assured  efficiency  in  ampli' 

fication.  Since  1919  AxL'AMERiCANAudios 


Self-Tuned 


R.  F.  Transformer  t. gift 

Wound  to  suit  the  tube. " — —&^s 
R-199 $5.00  R-201A $5.00 

Long  Wave 
Transformer  (Inter- 
mediate Frequency) 
4,000  to  20.000  meters. 
(15-75  kc.)R-110  $6.00 

10,000  Meter 
*    (30  Kc) 
Transformer 

Tuned  type  (filter  or 
input).  R-120...$6.00 


Radio  Frequency 

7^  ^(Oscillator)Coupler 

"  /Range  150to650meters. 
R-130 $5.00 


Super-Fine  Parts 

Consisting  of  three  R-110's,  one 
R-120  and  one  R-130 


have  answered  the  demand  for  an  instni' 
ment  that  couldbere/iedupon  for  maximum 
amplification  and  faithful  tone  reproduc- 
tion.  Set  builders  who  know  radio  do  not 
experiment — they  specif  yAix- Americans, 
with  full  assurance  that  they  will  consist 
tently  perform  with  highest  efficiency. 

Precision-Made 

All- American  reliability  is  a  natural  result  of  All- 
American  precision  manufacture.  Each  partis  scien- 
tifically designed  and  accurately  built  to  exact  stand- 
ards. Special  machinery  and  testing  equipment  assist 
in  achieving  perfection. 

When  you  are  buying  a  new  set,  look  under  the  lid 
for  All- American  Audios.OrinstallAiL- Americans 
in  your  present  set  if  it  is  not  already  equipped  with 
them.  You'll  appreciate  the  difference  in  amplifica- 
tion. 3  to  i  Ratio,  $4.50.  5  to  1  Ratio,  $4.77.  10 
to  1  Ratio,  $4.75. 


The  Radio  Key  Book 

The  most  valuable  book  of  radio 
facts  ever  published,  contains  prac- 
tical helps  and  tested  hook-ups. 
Sent  for  10  cents,  coin  or  stamps. 


All-American 
Reflex  Receivers 


Complete  receiving  sets,  with  all  instruments  mounted  on 
panel  and  baseboard  ready  to  be  wired.  Clear  photographs, 
blueprints  and  a  48-page  instruction  book  makev  iring  so  easy 
as  to  be  the  work  of  om/one  delightful  evening. 
All-Amax  Junior  is  a  one-tube  set  with  remarkable  selectiv- 
ity and  volume.  It  tunes  out  the  locals  and  gets  real  distance, 
or  it  brings  in  the  local  stations  on  the  loud  speaker. 
All-Amax  Senior  is  a  three-tube  set  with  three  stages  of  r.  f. 
amplification,  crystal  detector  and  two  stages  of  audio.  It  is 
highly  sele  ctive  and  brings  in  the  far-distant  stations  on  the 
loud  speaker. 

All-Amax  Junior  (semi-finished) $22.00 

All-Amax  Senior  (s^mi-finished)    .......      42.00 


RAULAND  MFG.  CO. 


Pioneers    in    the    Industry 

2680  Coyne  St.,  Chicago 


BORIC 


OVER  A  MILLION  ALL-AMERICAN  STANDARD  AUDIOS  IN  SERVICE 


*     Tested  and  Approved  by  RADIO  AGE    *' 


6  RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


RADIO  SATISFACTION 
T  LOW  LOSS  NAMELESS 


B-T 

LIFETIME 

CONDENSER 

Type 

Capac 

ty 

Price 

U7 

125 

$4.25 

J 1 1 

250 

4.50 

L-23 

500 

5.00 

L-35 

725 

6.50 

B-T  LOW  LOSS  TUNER 

Made  in  two  types  for  Broadcast 
or  Short  Wave.  Ranges  covered 
with  250  M.M.F.  L-l I  Condenser. 
Type  B  200  to  565  $5.00 

TypeSW        50  to  150  5.00 


B-T  VERNIER  CONDENSER 

(With  3  in.  dial) 
Type  Capacity  Price 

V-ll  250  M.M.F.  $4.50 

V-23  500  M.M.F.  5.00 

V-43  1000  M.M.F.  6.00 


In  no  other  five-tube  set  can  you 
get  such  hair-line  selectivity,  dis- 
tance, volume  and  tone  purity 
at  a  price  so  pleasant  to  the 
pocket  book. 

This  year  during  the  Interna- 
tional Tests  hundreds  of  Name- 
less owners  reported,  and  had 
verified,  their  successful  recep- 
tion of  English,  French,  German, 
Spanish,  Dutch  and  Mexican 
stations. 

Under  ordinary  conditions,  when 
the  usual  barrage  of  nearby  high 
power  stations  are  on  the  air, 
the  Nameless  displays  unusual 
ability  in  bringing  in  distant 
stations.  The  inherent  select- 
ivity of  the  circuit  is  further  im- 
proved by  the  adjustable  pri- 
mary in  the  antenna  circuit 
transformer  which  permits  you 
to  meet  your  local  requirements. 

The  advanced  low  loss  design  of  the  B-T 
Lifetime  Condensers  and  Low  Loss  3- 
Circuit  Transformers,  plus  the  electrical 
correctness  of  the  circuit  on  which  the 
Nameless  is  based,  have  as  a  natural  re- 
sult, great  range,  volume,  distance  and 
distortionless  reproduction. 

If  you  are  going  to  build  a  receiving  set 
you  will  be  well  repaid  in  improved  results 
and  money  saved  if  you  make  a  point  of 
S22ing  the  B-T  Kits  at  your  dealers  be- 
fore you  go  ahead.  A  postcard  will  bring 
you  our  folder  RF-32  which  give  more 
details  of  the  Nameless — the  radio  set 
without  a  regret. 

BREMER-TULLY 

MANUFACTURING 

COMPANY 

532  S.  Canal  St.    Chicago,  111. 


B-T  LOW  LOSS  NAMELESS  KITS 

Kit  No.  3  contains  three  250  M.M.F. 
Lifetime  Condensers,  three  Low  Loss  3- 
Circuit  Transformers,  one  40  M.M.F. 
Control  Condenser  with  1"  Dial  and 
complete  blue  prints,  instructions  and  a 

list  of  other  necessary  parts $26.50 

Kit  No.  1  contains  three  Low  Loss  Trans- 
formers only  (Nameless  blue  prints  sell 
separately  for  $1.00) $10.50 


B-T  AIR  CORE  TRANSFORMER 

Type  AC- 3  as  illustrated  has  adjustable 
untuned  primary.  Type  AC- 1  has  fixed 
primary. 

Type  AC-3 $3 .  50 

Type  AC-1 2.50 


*      Teztpd    n.nd   Avpwprl    hy    RADIO    AOR      # 


RADIO  AGE  for  February,  1925 
riiiiiiagmiiiiiiaiiii  lll»i  ILIflflll 


The  Magazine  of  the  Hour 


Voltage 

of 
Tubes 

No.  ' 

or 

Type 
of 

Totnl 
Rated 

Drain 

Pres,.5^™™d 

,:,„,„     f 

S'.%m 

<v}'i;::\ 

' 

5-Volt 

Tubes 

C-300  and  UV-200 
arelnterchange1- 

C-301A,  DV-2  and 

UV-201A  are  In- 

terchangeable 

Copyright.  1925 

The  Tresf  O-Lite 

Co.,  Inc. 

1 

UV-200 

1 

69  WHR 

22 

67  WHR 

16 

2 

UV-201A 

'/> 

67  WHR 

33 

i 

2 

1  UV-200 
1  UV-201A 

m 

611  WHR 

22 

69  WHR 

17 

3 

UV-201A 

V, 

69  WHR 

29 

67  WHR 

3 

1  UV-200 

2  UV-201A 

m 

611  RHR 

21 

HI  WHR 

IS 

4 

UV-201A 

i 

69  WHR 

22 

67  WHR 

16 

4 

I  UV-200 
3  UV-201A 

Wt 

613  RHR 

22 

611  RHR 

18 

5 

UV-201A 

m 

611  WHR 
MWHR 

~17 

5 

1  UV-200 
4  UV-20IA 

2 

613  RHR 

19 

611  RHR 

15 

6 

UV-201A 

PA 

611  RHR 

21 

611  V  IIR 

18 

8 

UV-201A 

2 

613  RHR 

19 

611  RHR 

15 

For  i 

ets  using  cur- 
it  a  rate  higher 

2'/4 

69  KRL 

22 

69  KPR 

18 

2l/2 

69  KRL 

|>9  KPR 

19 

What  size  batteries 

will  work  best  in  your  set? 


Selecting  storage  batteries  of  the 
right  size  and  capacity  is  necessary, 
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RADIO  AGE  for  February,  1925 


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77?e  Magazine  of  the  Hour 

aai IBl iwi  inn 


«52fe  Marine  of  the  Hour 


Af.  B.  5m  ft h 

Business  Manager 


A  Monthly  Publication 

Devoted  to  Practical 

Radio 


Frederick  A.  Smith 

Editor 


=JHE=£! 


A  Set  for  the  Experimenter- 


A  "SURE  SHOT"  Super-Het 


THE  design  of  this  super-heterodyne 
was  made  with  the  idea  in  mind 
to  design  a  set  that  could  be  con- 
constructed  by  the  average  experimenter 
and  to  work  like  a  laboratory  product. 

This  is  made  possible  by  the  design 
of  the  tuned  long  wave  amplifier  which 
automatically  eliminates  the  slightest 
possibility  of  doubt  as  to  whether  or  not 
the  long  wave  amplifying  transformers 
are  working  at  the  same  wavelength. 
Also,  the  method  of  wiring  which  is  used 
in  this  set  reduces  the  coupling  between 
the  successive  stages  of  radio  frequency 
amplification  to  the  point  where  the  out- 
fit is  most  stable. 

Further,  the  method  of  wiring  and  coil 
mounting  removes  the  necessity  of  inner 
stage  shielding,  which  usually  introduces 
serious  eddy-current  losses  and  at  the 
same  time  complicates  the  construction. 

Plate  Current  Small 

THE  "A"  battery  supply  may  be  deriv- 
ed from  either  three  dry  cells  or  a  four 
volt  storage  battery.  The  plate  current 
is  very  small  (8  Milliamperes).  This  is 
because  199  tubes  are  used  and  the  grids 
are  all  kept  at  a  high  negative  potential. 
A  201-A  tube  can  replace  the  199  tube 
in  the  second  stage  of  audio  frequency 
amplification.  Obviously  the  six  199 
tubes  must  be  put  on  one 
rheostat  and  the  201-A  on 
another. 

At  all  times  the  fila- 
ments of  the  tubes  (the 
199  tubes  in  particular) 
must  be  kept  down  as 
much  as  possible,  as  a 
slight  over-load  greatly 
decreases  their  life. 

When  a  super-hetero- 
dyne does  what  a  three 
tube  set  should  do,  the 
trouble  usually  lies  in  the 
long  wave  amplifier. 
Failure  of  this  very  im- 
portant part  of  the  set  to 
give  a  great  gain  is 
usually  due  to  the  follow- 
ing: Above 

Transformers  not  work-  McCullah's 

ing    at    the   same   wave-         turns.    The 


By  ARTHUR  B.  McCULLAH 

A  Tuned  Long  Wave 
Amplifier    Big    Aid 

length  as  the  transformers  are  peaked 
at.  This  latter  failure  predominates 
when  working  at  the  longer  wavelengths; 
that  is,  in  the  neighborhood  of  6,000 
to  10,000  meters;  i.  e.,  Mr.  Trans- 
former Manufacturer  will  specify  that  a 
.0003  fixed  condenser  must  be  placed 
across  his  filter  transformer  to  tune  it  to 
the  wavelength » the  transformers  are 
fixed. 

Now,  Mr.  Condenser  Manufacturer 
says  our  fixed  condensers  will  vary  within 
20  per  cent  of  their  rated  capacity.  This 
means  that  you  are  running  a  small 
chance  in  getting  your  filter  tuned  to  the 
same  wavelength  as  your  transformers  are 
designed  for. 

This  condition  does  exist  and  many 
three  stages  of  long  wave  amplification 
are  giving  less  amplification  than  one 
stage  that  is  working  properly. 

Watching  the  Transformers 

WHEN  working  at  the  shorter  waves, 
1,000  to  3,000  meters,  both  of  the 


said  difficulties  are  encountered,  making 
the  long  wave  amplifier  a  hopeless  mess 
unless  the  transformers  are  accurately 
matched  (also  with  the  filter)  and  to  do 
this  is  above  the  ability  of  the  average 
experimenter. 

There  has  been  much  discussion  in  cur- 
rent issues  of  different  radio  journals  as  to 
the  proper  wavelength  at  which  to  ampli- 
fy, in  a  super-heterodyne.  Some  writers 
will  make  their  choice  with  purely  theo- 
retical efficiency  in  mind.  Another  author 
in  making  his  choice  has  considered  both 
the  theoretical  efficiency  plus  the  prac- 
ticability of  such  a  design.  This  is  the 
probable  reason  for  such  a  vast  difference 
in  opinions. 

The  tuned  long  wave  amplifier  is  an 
expedient,  but  is  a  bit  more  difficult  to 
build.  Once  finished,  you  can  be  sure 
that  you  have  all  that  can  be  had  in  an 
amplifier. 

On  account  of  the  high  efficiency  ob- 
tained with  the  tuned  long  wave  ampli- 
fiers, only  two  stages  are  needed.  That 
is,  with  two  stages  of  long  wave  amplifi- 
cation, this  super  will  get  down  to  the 
"noise  level"  under  average  conditions. 
What  is  more,  the  fewer  the  stages,  the 
more  stable  our  set  will  be,  because  there 
is  less  chance  for  inter-stage  reactions; 
also,  if  the  same  out-put  can  be  had  with 
less  stages,  our  set  will 
be  more  efficient. 

The  reduction  of  the 
number  of  tubes  reduces 
the  size,  initial  cost  and 
up-keep. 


List,   of  Parts 
Required 


is  shown  the  method  of  wiring  the  oscillator  coil  for  Mr, 
super-heterodyne.  LI — 20  turns;  L2 — 30  turns;  Li — 30 
bakelite  tube  is  2  1-2  inches  in  diameter  and  3  inches  long. 


1  Front  panel  8"x30" 
x3-16" 

2  Bakelite  strips  1-2  "x 
18"xl-4"  (coil  mountings) 

1  Bakelite  strips  1  1-2" 
x24  "x  1-4  "  (To  mount  soc- 
kets) 

1  Bakelite  strips  3  1-2" 
xl8"xl-4"  (Condensers 
mountings) 

2  Pieces  brass  rod  3-8" 
square  3  3-4"  long 

2    [^Pieces      brass     rod 


10 


RADIO  AGE  for  February,  1925 


5 
* 

«* 


0.     K 
--4  <-> 


■fe 


The  wiring  diagram  of  Mr.  McCullah's  "sure  shot"  super-heterodyne.  This  sel 
is  designed  especially  for  the  experimenter,  and  yet  results  show  that  it  is  rarely  exceeded 
as  far  as  DX  work,  selectivity  and  clarity  of  tone  are  concerned.  All  wires  below  the 
dotted  portion  of  the  diagram  are  included  in  the  cable. 


3-8"  square  2  1-2"  long 

2  .0005  mfd.  variable  condensers 

3  .0005  mfd.  variable  condensers 
1  4  spring  jack 

1  2  spring  jack 
1  On-off  switch 
1  Ten  to  fifteen  ohm  rheostat 

1  200  to  400  ohm  potentiometer 

2  Four  inch  dials 


6  400  turn  coils  (Of  good  make) 

3   Pieces    Bakelite    tubing    2"     diam. 
3    1-2"  long 

7  199  tube  sockets 

3  .5  mfd.  by-pass  condensers 
1   .002  fixed  condenser 
1   Bakelite   tubing    2    1-2"   diam.    x3 " 
long. 


The  Magazine  of  the  Hour 

1  Bakelite  tubing  1  1-2"  diam.  xl" 
long 

2  Audio  transformers  (Of  Good  Make) 
1  Midget     condenser  .000045 

m.f.d. 

1  .00025  grid  condenser 
1  Three  meg.  grid  leak 
1   Loop   with  center  tap 

3  Three  inch  dials 

60  Feet  rubber  covered  wire 

Miscellaneous  nuts,  bolts  and    screws. 

The  best  of  parts  must  be  procured 
for  this  set  as  the  best  are  none  too  good. 

After  procuring  all  of  the  parts  listed 
from  a  reliable  dealer,  the  builder  should 
proceed   to   grain   and   drill   the   panels. 

The  graining  of  the  panels  can  be  done 
nicely  with  Number  One  steel  wool, 
rubbed  lengthwise.  After  this  a  few  drops 
of  oil  are  put  on  the  panel  and  rubbed 
with  a  piece  of  clean  waste. 

Mounting  the  Sockets 

MOUNT  the  four  sockets  and  three 
variable  condensers  on  their  re- 
spective pieces  of  bakelite.  Drill  and  tap 
the  ends  of  the  four  brass  rod  for  a  6-32" 
machine  screw. 

After  the  front  panel  has  been  finished, 
mount  the  two  variable  condensers, 
rheostat,  potentiometer,  two  jacks  and 
an  on-off  switch.  Now  screw  front  panel 
to  base  board.  Mount  the  apparatus 
on  the  base  board,  leaving  planty  of  room 
for  the  cable  that  will  run  the  length  of 
the  set. 

The  oscillator  coil  is  wound  on  a  2  1-2  " 
tube,  3"  long.  The  pick-up  coil  is  wound 
on  a  1  1-2 "  tube  1 "  long.  This  coil  is 
made  to  rotate  within  the  larger  coil  so  as 
to  vary  the  coupling.  The  larger  tube  has 
two  windings  of  30  turns,  each  wound  in 
the  same  direction.  The  smaller  coil 
has  one  winding  of  twenty  turns  split  in 
the  center  so  as  to  let  the  shaft  go 
through.  Number  24  green  silk  wire  is 
used. 

The  wiring' is  the  only  difficult  part  of 
the  set.  The  wiring  diagram  shows  what 
wires  are  to  run  in  the  cable  (in  brief  all 
wires  but  the  grid  and  plate  wires  are 
run  in  the  cable). 

Small  finishing  nails  are  driven  into  the 
base  board  in  a  line  down  the  length  of 
the  set  and  opposite  the  points  where 
wires  come  out  from  some  piece  of  appa- 
ratus to  join  the  cable.  Several  nails 
can  be  seen  in  the  pictures. 

After  the  set  is  wired,  tie  the  cable 
with  some  waxed  string,  (any  telephone 
repair  man  will  show  you  how  to  tie  the 
cable). 

Now  you  are  ready  to  try  the  set  out. 
Set  the  three  variable  condensers  that 
tune  the  long  wave  amplifier  at  about 
three-fourths  of  the  way  in.  Connect 
up  the  batteries  with  the  usual  precau- 
tions; put  tubes  in  the  sockets  and  pro- 
ceed to  tune  in.  If  the  set  is  connected 
right,  it  will  pick  up  some  local  stations 
immediately.  After  you  pick  up  a  local 
station,  readjust  the  three  variable 
condensers  in  the  long  wave  amplifier 
until  you  get  maximum  signal  strength. 
Now  try  to  pick  up  some  distant 
stations  and  make  some  adjustments  on 
the  regenerative  condensers  and  the  pick 
up  coil. 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


11 


The  use  of  the  cable  method  of  wiring 
may  seem  quite  a  radical  departure  from 
the  usual  method.  However,  it  has 
proven  its  efficiency  and  is  used  in  any 
number  of  high  grade  commercial  sets 
today.  The  builder  must,  however, 
bear  in  mind  the  fact  that  all  wires  that 
connect  the  plate  and  grid  circuits  must 
be  left  out  of  the  cable  and  not  run 
parallel  to  one  another  for  any  great 
distance.  When  a  section  of  cable  is 
completed  and  ready  to  be  bound  to- 
gether, it  should  be  done  in  the  following 
manner:  Take  a  long  piece  of  waxed 
string  and  fasten  it  securely  to  one  end 
of  the  bundle  of  wires,  and  by  looping 
a  series  of  half  hitches,  at  intervals  of 
about  one  inch,  the  entire  length  of  the 
wire  to  be  bound,  you  will  find  upon 
completion  that  the  cable  is  quite  sturdy 
and  will  not  easily  be  jarred  out  of  place. 

Long  Wave  Transformers 

TO  MAKE  the  long  wave  transform- 
ers, proceed  as  follows:  Take  the 
six  400-turn  honey-comb  coils  and  mount 
them  on  the  three  pieces  of  bakelite 
tubing  that  have  been  procured  for*this 
purpose.  If  you  cannot  get  bakelite 
or  other  tubing  whose  outside  diameter 
does  not  correspond  with  the  inside 
diameter  of  the  honey-comb  coils,  get 
the  size  tubing  just  under  the  inside 
diameter  of  the  honey-comb  coils  and 
split  it  (the  tubing)  the  entire  length 
of  one  side.  This  will  permit  the  tubing 
to  expand  enough  to  insure  a  snug  fit 
inside  the  coils. 

The  three  long  wave  radio  frequency 
transformers  are  then  mounted  on  their 
base,  which  is  the  two  bakelite  strips 
one-half  inch  wide  and  eighteen  inches 
long  by  one-quarter  inch  thick.  These 
strips  are  laid  one  on  top  of  the  other 
and  holes  drilled  at  intervals,  to  be 
determined  by  the  experimenter  after 
he  has  purchased  the  honey-comb  coils. 
The  three  long  wave  transformers  should 
be  separated  equal  distances  one  from 
the  other.  You  can  use  long  brass  bolts 
for  fastening  the  transformers  to  the 
bakelite  strips.  It  is  well  to  mount  the 
transformers  so  that  there  will  be  a  little 
clearance  between  the  bottom  of  the 
coils  and  the  baseboard.  Mounting 
them  on  the  bakelite  strip  is  to  permit  of 
changing  the  angle  between  them  and 
thus  reduce  the  inductive  coupling  be- 
tween them  to  a  minimum. 

As  before  mentioned,  the  oscillator 
coil  is  wound  on  a  tube  three  inches 
long  and  two  and  one-half  inches  in 
diameter.  Our  sketch  shows  the  con- 
nections leading  to  four  binding  posts 
mounted  on  the  tube.  Soldering  lugs 
can  be  substituted  for  the  binding  posts 
if  the  experimenter  wishes.  The  pick-up 
coil  is  wound  on  a  tube  one  inch  long 
and  one  and  one-half  inches  in  diameter. 
Twenty  turns  of  Number  24  double  silk 
covered  wire  are  wound  on  this  piece 
of  tubing,  ten  turns  on  each  side  of  the 
shaft.  Both  sides  of  the  coil  must  be 
wound  in  the  same  direction.  The  draw- 
ing shows  both  ends  of  the  inner  sides 
of  the  coil  connected  together,  while 
the  start  and  finish  of  the  coil  are  con- 
nected to  the  shaft.  The  builder  can 
bring  the  start  and  finish  wires  through 
a  hollow  shaft.     If  he  decides  to  do  this. 


A  side  view  of  the  super-heterodyne,  showing  the  method  of  installing  the  201 A 
tubes  in  the  push-pull  audio  amplifier. 


he  must  remember  to  use  flexible  wire 
in  making  this  connection.  Number 
24  double  silk  covered  wire  is  used  on 
both  the  oscillator  and  pick-up  coil. 

The  design  of  the  front  panel  is  left 
to  the  builder's  taste.  The  only  thing 
that  is  necessary  to  have  on  the  main 
operating  panel  is  the  secondary  and 
oscillator  condensers  and  a  filament 
control  switch,  which  enables  the  oper- 
ator to  turn  the  filament  current  off  at 


will  without  having  to  remove  one  of 
the  battery  leads  from  the  battery,  the 
rheostat  and  the  potentiometer. 

Watch  Wiring  Diagram 

["  TSE  great  care  in  following  the  wiring 
^— '    diagram  of  the  oscillator  circuit  and 

no  trouble  will  be  experienced  in  making 

the  heterodyne  unit  oscillate. 

The  secondary  of  the   three  air  core 

long  wave  radio  frequency  transformers 


The  experimental  model  of  the  McCullah  super-het,  showing  the  possibilities  of 
condensing  the  outfit  by  mounting  the  audio  amplifier  under  long  wave  amplifiers: 


12 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


is  tuned  with  three  .0005  mfd.,  variable 
condensers  that  are  to  be  mounted  on  a 
sub-panel  three  and  one-half  inches  wide, 
eighteen  inches  long  and  one-quarter 
of  an  inch  thick.  This  is  done  so  that 
once  the  condensers  are  adjusted,  they 
will  be  out  of  reach  and  you  will  not  be 
tempted  to  turn  them  and  throw  the 
entire  long  wave  amplifier  out  of  tune. 
After  the  condensers  are  mounted  on 
the  sub-panel,  the  panel  and  condensers 
are  mounted  on  the  end  of  the  baseboard 
farthest  away  from  you,  using  the  two 
pieces  of  brass  rod  two  and  one-half 
inches  long  and  three-eighths  inch  square. 
The  photograph  on  page  11  will  show 
this  quite  clearly. 


there  is  today,  he  may  at  times  wonder 
how  he  is  to  know  just  what  is  the  best. 
It  is  very  easy  to  determine  just  what  is 
best  if  you  will  but  pay  a  little  attention 
to  the  manufacturer  of  the  kind  of 
apparatus  you  want.  Do  not  purchase 
any  equipment  from  a  manufacturer 
who  will  not  guarantee  his  products, 
or  from  people  who  are  known  to  be 
"bootleggers." 

The  variable  condensers  used  in  tuning 
the  long  wave  amplifier  do  not  have  to 
be  verniers,  neither  do  they  have  to  be  of 
the  more  expensive  low  loss  type.  If 
condensers  of  the  type  that  permit 
high  losses  are  used,  the  efficiency  of  the 
set  is  nil.     The  oscillator  condenser  and 


tubes,  build  for  that  purpose.  If  not, 
the  smaller  sockets  should  by  all  means 
be  used. 

The  set  can  be  made  in  a  real  portable 
manner  if  the  lower  picture  on  page  11 
is  followed.  To  do  this,  the  sub-panel 
on  which  the  three  variable  condensers 
are  mounted  is  omitted  and  they  are 
mounted  at  right  angles  to  the  bakelite 
base  on  which  the  tubes  are  mounted. 
Of  course,  it  will  be  necessary  to  procure 
a  longer  piece  of  bakelite  for  this  purpose 
than  the  one  originally  specified.  It 
would  be  best  for  the  builder  to  deter- 
mine the  length  of  this,  as  he  will  know 
just  how  wide  he  will  want  the  set  to 
be.  The  audio  frequency  amplifiers 
can  be  mounted  under  the  detector  tube 
as  shown  at  the  extreme  right  hand  side 
of  the  picture. 

In  the  upper  photograph  on  page  11 
is  shown  the  circuit  with  push  pull 
amplification.  This  is  added  in  the 
usual  manner,  but  it  has  been  found  best 
to  use  the  larger  type  tubes  for  this 
purpose.  This  will  necessitate  the  in- 
stallation of  another  rheostat,  to  control 
the  push  pull  amplifier  and  a  modifica- 
tion in  the  "A"  battery  current  supply 
to  compensate  for  the  increased  amount 
of  current  consumed  by  these  tubes. 
It  is  best  to  install  push  pull  amplifica- 
tion after  one  stage  of  straight  audio 
has  first  been  added. 

In    purchasing    the    audio    frequency 


The  incomplete  experimental  model, 
showing  how  the  nails  are  used  in  laying 
the  cables. 

After  you  have  mounted  the  four 
vacuum  tube  sockets  on  the  piece  of 
bakelite,  one  and  one-half  inches  wide, 
twenty-four  inches  long  and  one-quarter 
inch  thick,  connect  the  filament  leads 
together  by  means  of  a  long  piece  of 
bus  bar  wire.  While  it  is  not  necessary 
to  use  bus  bar  wire  for  this  purpose, 
due  to  the  fact  that  this  is  such  a  long 
connection,  it  is  best  to  use  a  wire  that 
is  quite  firm. 

It  will  not  be  necessary  to  drill  holes 
for  mounting  either  the  midget  variable 
condenser  or  the  grid  leak  and  fixed 
condenser,  as  these  two  pieces  of  appara- 
tus are  so  light  that  they  will  practically 
support  themselves  when  soldered  to 
their  respective  places. 

It  might  be  well  to  state  that  the  grid 
leak  should  have  a  resistance  of  about 
three  megohms  and  the  condenser  (grid) 
capacity  should  be  .00025. 

The  builder  may  use  any  type  of  loop 
that  he  may  choose,  just  so  it  will  tune 
low  and  high  enough  to  cover  the  broad- 
cast range.  One  about  two  feet  square 
and  tuned  with  a  variable  condenser 
having  a  capacity  of  .0005  mfd  has  been 
found  to  give  excellent  results.  However, 
a  loop  of  this  size  is  not  absolutely 
necessary  as  some  of  the  smaller  ones  on 
the  market  are  every  bit  as  efficient. 

Watch     Your     Apparatus,     Too 

IN  CHOOSING  apparatus  for  a  circuit 
of  this  type,  the  builder  must  remem- 
ber (as  before  cautioned)  to  use  only 
the  best  obtainable.  With  such  a 
variety  of  equipment  on  the  market  as 


A  rear  view  of  the  Sure-Shot  super, 
mountings,  etc.,  are  made. 

the  condenser  across  the  loop  should 
be  of  the  low  loss  type,  having  a  straight 
line  wavelength  curve,  as  with  con- 
densers of  this  type  the  settings  for 
given  wavelengths  will  be  divided 
evenly  over  the  entire  dial. 

While  these  condensers  do  not  have  to 
be  of  the  vernier  type,  it  will  be  found 
convenient  at  times  to  have  some  means 
of  adjusting  them  very  finely.  For  this 
purpose  a  dial  or  a  device  that  will 
enable  you  to  move  them  a  mere  fraction 
of  an  inch  at  a  time  will  be  found  quite 
convenient. 

Be  careful  in  selecting  the  vacuum 
tube  sockets  and  do  not  get  those  that 
are  commonly  spoken  of  as  "moulded 
mud"  products.  Be  sure  that  the  con- 
tact prongs  are  springy  enough  to  touch 
the  prongs  on  the  tube  and  here  let  me 
advise  you  against  using  adapters.  If 
you  wish  to  use  the  set  with  the  larger 


Note  hoiv  the  cable  connections,  condenser 


transformers  it  might  be  well  to  suggest 
that  transformers  of  a  low  ratio  be  used, 
as  those  of  a  high  ratio  will  only  distort 
the  speech  and  music.  Two  transformers 
having  a  ratio  of  four  to  one  are  con- 
sidered the  ideal  type  to  be  used  in  an 
audio  amplifier  by  most  experimenters. 
As  the  output  of  signal  strength  is  so 
great  in  a  set  of  this  this  type  the  resis- 
tance coupled  style  of  amplifier  can  be 
used  quite  nicely  and  very  good  success 
has  been  reported  using  two  stages  of 
resistance  coi:pled  amplification  and  a 
straight  stage  of  audio.  The  output  from 
three  stages  of  resistance  coupled  ampli- 
fication is  about  as  great  as  the  output 
from  a  two  stage  audio  amplifier,  but  the 
clarity  of  tone  and  the  freedom  from  dis- 
tortion more  than  make  up  for  this  short- 
coming. 

Be  careful  in  making  your  connections 
to  solder  all  joints  that  you  possibly  can. 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


13 


An  All-Round  Receiver— 

The   3-Circuit   REGENERATOR 


By  BRAINARD  FOOTE 

<eSure Fire"  Tuning 
Control, 


THREE     tubes     is     practically     the 
minimum  number  that  is  suited  for 
really  satisfactory  year-round  loud 
speaker   receiving.    Of   course,    you    can 

employ   two    tubes,    with    reflexing   and       _  1  \  jr  """ 

have  fairly  good  loud  speaker  operation,      i^OntWL        MaXimUm     fo11™* 

but   in   sure-fire   tuning  control,   utmost  .       .        .  7—1  1  uv  20°  or  C  300  detector  tube 

sensitivity     and     in     quiet,     undistorted     OCnSHivitV         ±1,  Q.SV  2UV  201  A  or  C  301A  amPIiner  tubes 

amplification,    the   straight   regenerative 


1  .002  mfds.  fixed  condenser 
7  binding  posts 

10  lengths  bus  wire  for  connections 
Screws  to  mount  panel  to  cabinet 
The  accessory  equipment  is  listed  as 


detector  and  two  stage  amplifier  form  an 
unbeatable  combination. 

With  so  many  reasonably  priced  three 
circuit  couplers  available,  it  is  actually 
a  waste  of  time  and  a  very  slight  saving 
to  construct  your  own.  With  one  of 
these  instruments  and  a  good  variable 
condenser,  the  receiving  circuit  is  simple 
to  connect,  simple  to  tune  and  unequalled 
in  the  regenerative  field  for  its  selective 
ability,  DX  reception  and  accuracy  of 
its  dial  settings. 

Moreover,  the  outfit  can  be  assembled 
in  a  very  good  looking  style,  if  a  bit  of 
care  be  expended  in  the  arrangement  of 
the  panel  and  its  "fit"  in  the  cabinet. 
A  special  cabinet  was  built  for  the 
receiving  set  illustrated,  using  mahogany 
with  a  piano  finish  in  dark  walnut.  A 
cabinet-maker  did  the  job  for  fourteen 
dollars.  It  has  a  60  degree  slope  in 
front,  proportioned  to  take  a  7  by  18 
inch  mahoganite  panel  and  having  a  2 
inch  vertical  frontal  portion  for  added 
beauty. 

Cabinet  Construction 

r  I^O  obviate  joints  between  sides  and 
-*-  top,  the  opening  for  tubes  and  wiring 
is  in  the  form  of  a  rectangular  door  about 
12  by  7  inches,  located  in  the  rear. 
Beneath  it  is  a  slot  one  half  inch  in  width 
and  three  inches  long,  through  which  the 
flexible  connectors  for  batteries,  aerial 
and  ground  are  passed.  The  dials  for 
condenser,  coupler  and  rheostats  are  in 
mahoganite  likewise,  so  that  the  panel 
and  woodwork  of  the  cabinet  present  an 
appearance  of  elegance  and   refinement. 

An  added  fea- 
ture is  the  self- 
contained  loud 
speaker — an  idea 
which  may  not  ap- 
peal to  some  of  you, 
but  which,  on  the 
whole,  seems  quite 
pleasing  both  in 
appearance  and  in 
results.  The  horn 
is  a  small  molded 
product  and  a  high 
quality  phone  unit 
is  fitted  to  it  by 
a  special  cap  in- 
cluded with  the 
horn.  Leads  from 
the  phone  unit  are 
in  the  form  of  a 
single  phone  cord, 
with  a  plug  at  the 
end.     The  phone  is 


with   this  Circuit 


not  permanently  connected  in  the  circuit, 
but  joined  to  the  plug  just  as  though 
it  were  an  external  speaker.  The  cord 
comes  out  the  rear  of  the  cabinet  along 
with  the  other  wiring. 

Two  jacks  are  provided,  one  giving 
access  to  the  detector  for  headphone 
use,  and  the  other  to  the  second  step 
of  the  audio  amplifier  for  the  loud 
speaker.  One  rheostat  controls  the 
detector  tube,  which  is  of  the  "soft" 
(200  or  300)  type,  while  the  other 
rheostat  regulates  the  filament  current 
of  both  of  the  amplifier  tubes. 

The  apparatus  required  for  the  set 
itself  is  as  follows: 

1  7x18  inch  cabinet 

1  7x18  inch  panel 

1  7x12  inch  panel  (as  sub- panel  inside) 

1  Loud  Speaker  horn  (if  desired) 

1  Phone  Unit  (if  desired) 

1  Three  Circuit  Coupler;  _^ 

1  Variable  Condenser  to  suit  the 
coupler 

1  6  ohm  rheostat 

1  10  ohm  rheostat 

4  dials  for  above  instruments 

1  single  circuit  jack 

1  double  circuit  jack 

1  phone  plug  and  cord  (for  loud 
speaker) 

3  tube  sockets 

2  audio  frequency  amplifying  trans- 
formers 

1  .00025  mfds.  grid  condenser  and  2 
megohm  grid  leak 


The  parts  mounted  to  the  panel  are  few  and  their  arrangement  is  neat.  The  loud 
speaker  horn  is  a  novel  feature,  being  included  in  the  cabinet.  Any  high  quality  type 
of  three  circuit  coupler  will  answer  the  purpose. 


1  6  volt  storage  battery 

2  45  volt "  B  "  batteries  with  2  2  K  volt  tap 
Aerial  and  Ground  equipment 
Lamp    Cord    for    set    connections    to 

batteries 

Loud  Speaker  unless  included  in  set 
Headphones  if  desired  (for  DX  work 

on  detector  tube) 

Using  a  Vernier  Control 

HPHE  three  circuit  coupler  is  usually 
-*-  accompanied  by  specific  directions 
for  its  installation  and  use.  The  size 
of  variable  condenser  needed  with  it  is 
ordinarily  mentioned,  too.  This  con- 
denser should  preferably  be  equipped 
with  a  vernier  control  of  some  sort, 
or  else  a  vernier  type  of  dial  may  be 
purchased  for  it.  The  vernier  should 
not  be  in  the  form  of  an  extra  plate  or 
the  type  that  changes  the  distance 
between  the  plates,  as  these  prevent 
accurate  "logging"  of  the  dial  adjust- 
ments for  different  stations. 

The  incorporation  of  "low-loss"  ap- 
paratus will  go  far  toward  increasing  the 
receiving  radius  and  at  the  same  time 
the  selectivity  of  the  outfit.  This  applies 
in  particular  to  the  coupler  and  the 
variable  condenser.  The  panel  is  laid 
out  first  and  the  parts  are  situated  with 
an  eye  toward  effective  balance  and 
symmetry.  The  rear  view  of  the  panel 
shows  just  what  parts  are  mounted  on 
it  and  where  they  ought  to  go.  In  case 
you  decide  to  use  an  external  loud 
speaker,  the  two  jacks  and  the  two 
rheostats  may  be  raised  nearer  to  the 
center  line,  or  one  jack  might  be  placed 
beneath    each   rheostat   to    preserve   the 

good    looks    of    the 

layout. 

The  Wiring 

Wherever  pos- 
sible, use  connec- 
tions to  binding 
post  in  place  of 
soldered  lugs  or 
soldered  joints  of 
any  sort.  Not  only 
does  soldering  make 
for  a  weak  joint 
mechanically,  but  it 
means  more  places 
for  corrosion  to  take 
place.  Good  con- 
nections may  be 
made  with  one  of 
the  new  radio  tools 
now  on  the  market, 
built  something  like 
a  pair  of  pliers  but 


14 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


having  a  rounded  nose  on  which  a  neat 
loop  may  be  formed  for  fastening  beneath 
the  binding  post  screws. 

The  7x12  inch  sub-panel  is  useful  for 
assembling  the  three  sockets,  the  audio 
transformers  and  the  binding  posts. 
These  last-named  may  be  suspended 
on  a  separate  "bind- 
ing post  panel"  as 
illustrated  if  this 
stunt  appeals  to 
you.  In  fact,  such 
panels  may  be  ob- 
tained all  ready  for 
use,  drilled  for  seven 
or  eight  posts.  Wir- 
ing on  the  main 
panel  and  sub-panel 
should  be  done  in- 
dividually, locating 
all  the  wires  that  do 
not  interconnect  be- 
t ween  the  two 
panels.  Then,  the 
panels  are  placed 
in  the  same  physical 
relation  to  each 
other  that  they  will 
have  in  the  finished 
receiver,  whether 
the' cabinet  chosen 
be  sloping  or  up- 
right. 

Bus  wiring  be- 
tween the  two 
panels  will  serve  to 
hold  them  together 

until  they  are  placed  in  the  cabinet, 
where  both  may  be  screwed  firmly  into 
position.  With  the  connections  complete, 
you  are  ready  for  the  installation  of  the 
set  with  its  accessories.  The  aerial  and 
ground  system  are  standard  so  far  as 
dimensions   and   erection    go. 

The  antenna  should  preferably  be  all 
one  wire  from  its  outer  end  right  to  the 
antenna  binding  post,  to  eliminate 
soldered  joints.  It  passes  through  a 
porcelain  tubing  either  through  the  wall 
or  the  window  frame.  The  ground  lead 
may  be  another  length  of  the  same  type 
of  wire,  running  without  joints  from  the 
ground  binding  post  right  to  the  water 
or  steam  pipe,  where  a  connection  is 
made  with  a  ground  clamp.  The  pipe 
must,  of  course,  be  scraped  clean  down 
to  the  bright  metal  before  the  clamp  is 
put  on. 

The  "soft"  type  of  detector  tube  makes 
for  extreme  sensitivity,  once  its  filament 
be  correctly  adjusted.  It  is  important 
to  get  its  "grid  return"  lead  on  the 
negative  side  of  the  filament.  If,  however, 
you  decide  to  employ  a  hard  tube  for 
the  detector,  this  lead  should  go  to  the 
positive  side  of  the  filament  instead.  In 
the  case  of  the  soft  tube,  the  filament 
rheostat  should  be  turned  up  to  a  point 
just  below  that  brightness  at  which  a 
"hissing"  noise  begins. 

Tuning 

T^HERE  is  only  one  knob  that  is 
•*-  called  upon  for  extensive  operation — ■ 
that  of  the  tuning  condenser.  With 
such  a  setting  of  the  tickler  dial  that  no 
whistles  or  squeals  are  heard,  it  is 
possible  to  tune  from  low  wavelengths 
to    high    wavelengths    by    a    progressive 


movement  of  the-  condenser  dial.  All 
local  stations  will  then  be  heard  clearly. 
For  distance  work,  it  becomes  necessary 
to  advance  the  position  of  the  tickler 
dial  to  secure  regeneration — but  you 
should  be  very  careful  not  to  advance  it 
enough    to   cause    whistles   and   squeals. 


HHBBHl 

■ 

Jtt          ..■■•■:■•'                           •  ■'  ■  t 

1 

PH 

//  you  like  a  sloping  model  of  cabinet,  here's  one  that  is  particularly  handsome. 
The  three  circuit  tuner  is  used  for  reception,  with  a  two  stage  amplifier,  and  the  outfit 
has  a  self-contained  loud  speaker.     Make  yourself  one! 

When  you  do  this,  you  interfere  with 
other  listeners  round  about  you  and  it 
is  not  necessary  to  actually  arrive  at  the 
point  of  "oscillation"  where  such  noises 
commence  in  order  to  make  your  receiver 
sensitive  to  distant  signals. 

Keep  a  Log,  Too 


^^OU    also    ought    to    keep    a 
*-  list    of    all    the    stations    you 


careful 
hear, 

together  with  their  advertised  wave- 
lengths and  the  dial  readings  of  the 
condenser  dial  at  which  these  stations 
are  heard.  Not  only  will  this  help  you 
locate  them  again,  but  at  the  same  time 
it  will  enable  you  to  know  pretty  closely 
the  setting  of  your  dial  for  any  wave- 
length. And  if  you  are  trying  your  best 
to  "log"  some  DX  stations,  you  will 
then  know,  for  instance,  that  KDKA 
comes  in  at  26  and  you  won't  waste  time 
trying  to  get  the  call  letters  of  a  station 
coming  in  at  that  setting,  for  it  must  be 
KDKA. 

The  three  circuit  tuner  is  particularly 
easy  to  control  for  another  reason. 
The  coupling  between  the  antenna  and 
the  set  is  constant  and  therefore  the 
tickler  dial  is  practically  constant  for 
good  regeneration  no  matter  where  the 
tuning  condenser  is  set. 

This  means  that  the  tickler  dial  need 
scarcely  be  touched  and  means  that  as  a 
critical  control,  the  tickler  is  no  annoy- 
ance. 

All  in  all,  there's  no  set  so  easy  to 
operate  and  so  extremely  satisfying  in  its 
results  in  comparison  to  the  expense 
entailed  and  the  trouble  of  tuning  it. 
It's  really  the  standard  three  tube 
receiving  set  and  it  is  deservedly  the 
standard. 


MANY  of  our  readers  get  considerable 
enjoyment  out  of  constructing 
their  own  apparatus,  and  for  their  benefit 
the  following  instructions  will  enable 
them  to  build  the  three  circuit  tuner  as 
described  in  this  article. 

First,  procure  an  old  vario-coupler  and 
strip  it  of  all  wind- 
ing. The  tube  on 
which  the  tapped 
primary  was  wound 
will  be  from  3  to 
3  1-2  inches  in  dia- 
meter. Beginning  at 
the  lower  end  of  the 
tube,  approximate- 
ly 3-4  of  inch  from 
the  bottom,  wind 
15  turns  of  No.  22 
double  silk  insu- 
lated wire.  Anchor 
the  ends  of  this  coil 
by  drilling  small 
holes  in  the  tube  in 
the  proper  position 
to  take  the  end 
down  through  one 
hole  and  up  through 
the  other. 

These  holes 
should  be  about  1-4 
inch  apart  and  in 
line  with  the  wind- 
ing. At  a  distance 
of  1-8  of  an  inch 
from  this  coil,  start 
the  secondary  wind- 
ing, which  consists  of  40  turns  of  the 
same  kind  of  wire  used  in  making  the 
first  coil.  Both  the  starting  and  finishing 
ends  of  this  coil  are  anchored  in  the  same 
way.  Next,  the  rotor  is  to  be  wound 
with  42  turns  of  No.  26  double  silk  in- 
sulated wire  and  the  ends  fastened  to  the 
same  terminals  to  which  the  unwound 
coil  was  fastened.  This  completes  the 
tuner. 

Wind  in  Same  Direction 

It  might  be  well  to  state  that  the  two 
coils  wound  upon  the  tube  must  be 
wound  in  the  same  direction.  When 
mounted  in  the  set,  the  top  end  of  the  15 
turn  coil  is  connected  to  the  aerial  bind-, 
ing  post  and  the  lower  end  to  the  giound 
binding  post.  This  forms  the  primary 
winding.  The  top  end  of  the  40  turn  coil 
is  connected  to  the  grid  leak  and  conden- 
ser and  to  the  rotary  plates  of  the  varia- 
ble condenser,  and  the  other  end  to  the 
stationary  plates  of  the  variable  con- 
denser and  the  negative  side  of  the  "A" 
battery,  as  shown  on  the  wiring  diagram. 

One  of  the  rotor  terminals  is  connected 
to  the  top  spring  of  the  detector  jack  and 
the  other  terminal  to  the  plate  connection 
of  the  vacuum  tube  socket. 

Audio  Transformers 

13  EGARDING  the  audio  transformer, 
-*-  *■  if  the  builder  desires  to  obtain  ex- 
treme amplification  in  preference  to  good 
tone  quality  without  distortion,  then  one 
having  a  ratio  of  10  to  1  should  be  used 
in  the  first  stage  and  that  of  the  second 
stage  should  be  of  a  lower  ratio,  such  as 
3  1-2  to  1  or  4  to  1.  Two  low  ratio  trans- 
formers of  about  4  to  1  will,  however, 
give  much  better  musical  quality  to  the 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  How 


15 


reception,  although  perhaps  with  a  little 
less  volume. 

In  some  cases  better  reception  is  ob- 
tained if  a  fixed  mica  condenser  having 
a  capacity  of  .002  M.  F.  is  connected 
across  the  posts,  the  posts  marked  "P" 
and  "B"  positive  side  of  the  first  trans- 
former, but  whether 
or  not  this  will  be 
of  any  use  will  de- 
pend upon  the  par- 
ticular transformer 
used. 

It  is  sometimes 
advisable  to  substi- 
tute a  variable  grid 
leak  for  one  of  the 
fixed  type.  This 
should  be  mounted 
as  close  to  the  de- 
tector tube  socket 
as  possible.  This 
is  important,  as  a 
difference  of  one 
inch  in  the  length 
of  the  grid  leak, 
after  passing 
through  the  con- 
denser, may  cause 
the  set  to  howl.  No 
mistake  will  be 
made  if  it  is  soldered 
directly  to  the  bind- 
ing post. 

The  jack  used  to 
cut  in  on  the  detector  tube  should 
be  of  as  good  a  quality  as  it  is  possible 
for  the  builder  to  obtain.  This  is  usually 
considered  by  most  builders  as  a  most 
unimportant  piece  of  equipment.  How- 
ever, this  should  not  be  so,  as  if  the  jack 
is  of  poor  electrical  construction,  it  is 
possible  to  burn  out  all  the  tubes. 

How  many  times  have  you  heard  a 
fan  complain  that  his  audio  frequency 
amplifier  did  not  seem  to  work  right? 
Cases  of  this  kind  can  usually  be  traced 


to  the  failure  of  the  two  inner  prongs  to 
make  contact  when  the  plug  is  withdrawn. 
By  substituting  a  double  circuit  jack  for 
the  single  circuit  jack,  employed  in  the 
last  stage,  it  is  possible  to  connect  the 
loud  speaker  permanently  to  the  circuit. 
To  do  this,  the  two  outside  prongs  are 


Sockets  and  transformers  are  placed  on  a  separate  sub-panel  inside  the  set.  Binding 
posts  are  mounted  in  a  row  on  a  separate  strip  of  insulating  material.  Connections 
are  made  with  bus  bar  wire  and  as  little  soldering  as  possible. 


connected  in  the  usua.  manner,  while 
the  two  inner  ones  are  connected  to  the  loud 
speaker.  The  loud  speaker  is  thus  auto- 
matically put  in  the  circuit  when  the  tele- 
phone plug  is  removed  from  the  last  stage. 
Regarding  the  tuning  condenser,  the 
builder  is  advised  to  use  only  the  best 
obtainable,  as  this  is  one  of  the  most 
important  controls  in  the  circuit.  There 
are  at  present  many  good  condensers  on 
the  market  of  the  low  loss  type  that  will 
fit  in  this  set  very  well. 


As  the  capacity  change  in  a  straight 
line  condenser  is  so  gradual,  practically 
none  of  the  low  loss  condensers  is  offered 
for  sale  with  the  usual  vernier  plates. 
This  in  itself  is  quite  desirable,  as  it  is 
almost  impossible  to  satisfactorily  log  a 
set  that  employs  condensers  using  vernier 
plates.  It  becomes 
necessary  at  times  to 
use  a  device  where- 
by the  condenser 
can  be  adjusted 
finely. 

For  this  purpose 
a  vernier  type  dial 
is  usually  needed. 
One  can  be  pur- 
chased from  almost 
any  first  class  radio 
shop.  Be  sure  to 
obtain  one  that  is 
free  from  play  or 
back  lash. 

Probably  less  at- 
tention has  been 
given  to  the  aerials 
of  receiving  sets 
than  any  other  part 
of  the  entire  radio 
system,  and  a  few 
suggestions  to  the 
reader  concerning 
the  type  and  general 
construction  will 
not  be  amiss. 
[Due  to  the  fact  that  many  of  the  BCL'S 
were  smitten  with  the  radio  bug  in  the 
Winter,  and  with  the  usual  haste  of  a 
new  fan  threw  up  an  aerial  without  any 
definite  thought  as  to  efficiency,  appear- 
ance or  practibility,  just  as  long  as  it  was 
elevated  as  high  as  possible  and  as  long. 
Of  course,  it  is  not  very  nice  to  be  climb- 
ing over  gables  with  the  thermometer 
around  zero.  But  nevertheless,  your  set 
will  prove  more  efficient  if  you  but  take 
a  little  care  in  hanging  the  aerial. 


The  standardized  three  circuit  arrangement  is  employed.    One  jack  is  provided  for  headphones  and  another  for  loud  speaker.  The 
grid  return  from  the  detector  goes  to  the  "A"  minus  unless  a  "hard"  type  of  detector  tube  is  chosen. 


16  RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


Keeping  Timely  with  a 

Radio  CROSS-WORD  Puzzle 


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YOU  fellows  who  have  annexed  Dial 
Twister's  buttons  will  now  have 
a  further  opportunity  for  dis- 
tinguishing yourselves.  Just  sharpen 
up  the  old  lead  pencil  and  demonstrate 
your  acquaintance  with  radio  words  by 
working  our  radio  cross-word  puzzle. 
You  have  all  brought  in  DX;  now  let 
us  see  if  you  can  tune  in  a  word  of  three 
letters  meaning  "electronic  disturbance," 


By  JOHN  B.  RATHBUN 

and  make  it  fit  into  the  little  square 
checkerboard.  At  the  same  time  we 
would  like  to  know  how  long  it  took 
you  to  accomplish  this  feat,  whether 
thirteen  minutes  or  thirteen  hours,  so 
that  we  can  be  governed  in  laying  out 
the  cross-word  puzzles  of  the  future. 

Not  all  of  the  words  in  the  puzzle  are 
strictly  radio  words.  We  have  intro- 
duced   enough    everyday   expressions   to 


make  it  easy  for  beginners,  and  further, 
there  are  no  long  or  unusual  words, 
Just  plain,  everyday  words  that  have 
appeared  dozens  of  times  in  issues  of 
RADIO  AGE.  Roughly,  we  should 
say,  about  fifty  per  cent  of  the  words  are 
radio  terms  with  the  remaining  fifty 
per  cent  as  used  in  common  conversa- 
tion. Such  words  as  "dinosaurus"  or 
(Turn  to  page  71) 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


17 


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Efficiency  with  MATCHED  Parts 

A  SLIDE  WIRE  BRIDGE  FOR  MEASURING  CAPACITY 

AND  IMPEDANCE 


IT  OFTENTIMES  becomes  quite  a" 
problem  for  the  fan  who  delights 
in  building  his  own  receiving  set  to 
match  his  radio  frequency  transformers 
properly  or  to  build  transformers  or 
condensers  of  the  proper  impedance  or 
capacity,  because  of  the  difficulty  in 
having  them  measured  or  matched. 

Radio  frequency  transformers,  as  we 
all  know,  should  be  as  near  equal  to 
one  another  as  is  possible,  to  obtain  the 
most  efficient  results  when  placed  into 
a  set.  This  applies  to  the  intermediate 
frequency  transformers  of  the  super- 
heterodyne type  of  circuit  in  particular 
and  to  a  lesser  extent  to  the  neutrodyne 
and  tuned  radio  frequency  type  of  cir- 
cuits. These  transformers  may  be  con- 
structed exactly  alike,  to  the  turn  of 
wire,  and  to  the  length  of  wire  and 
spacing  of  turns,  yet  they  may  be  one  or 
two  hundred  meters  apart,  due  to  the  vari- 
ation of  the  wire  or  its  insulation,  density 
of  winding  or  capacity  between  windings. 

Take  the  condenser,  a  piece  of  equip- 
ment most  important,  yet  usually  very 
small,  where  capacity  must  be  as  near 
exact  as  possible  to  produce  the  best 
results.  All  one  can  do  is  either  take 
the  manufacturer's  stamp  as  final,  or 
he  can  figure  it  out  with  a  long  mathe- 
matical problem;  but  as  the  great  ma- 
jority of  broadcast  listeners  and  set 
builders  are  not  radio  or  electrical  engi- 
neers, this  becomes  too  deep  and  com- 
plicated. 

Not  So  Complicated 

The  measuring  and  balancing  of 
coils   and   condensers   is   not   a   hard   or 


By  H.  FRANK  HOPKINS 

Assoc.  A.  E.  E. 


complicated  operation;  in  fact,  it  be- 
comes almost  as  simple  as  tuning  his 
receiver  when  a  circuit  commonly  known 
as  a  "slide  wire  bridge"  is  set  up.  This 
circuit  is  simple  within  itself,  and  can 
be  built  in  the  form  of  a  portable  instru- 
ment at  small  cost,  as  described  in  this 
article. 


WHY  YOU  NEED  THIS 
UNIT 

The  success  or  failure  of 
most  radio  receiving  sets  de- 
pends on  whether  or  not  the 
apparatus  used  is  properly 
matched. 

If  your  radio  frequency  trans- 
formers are  not  as  equal  as 
possible,  your  results  will  not 
be  up  to  standard. 

Here  is  a  unit  that  enables 
you  to  determine  the  necessary 
capacity  of  your  condensers, 
transformers, inductances,  etc., 
and  thus  assure  yourself  that 
your  set  is  properly  laid  out. 

If  you  are  in  doubt  about 
the  procedure  outlined  in  this 
article,  do  not  hesitate  to  call 
upon  the  authpr  for  personal 
counsel. 


Material    Required   in    Building    the 
Instrument 

One  maple  disk  7"  in  diameter  (De- 
tail 1). 

One  Induction  Coil. 

One  High  frequency  buzzer  (900  to 
1000  Cycles). 

One  piece  No.  34  Bare  German  silver 
resistance  Wire  24"  Long. 

Eight  brass  binding  posts. 

One  composition  panel  8"x8"x3'16" 
(Detail  3). 

One  3-16"  Ball  bearing. 

One  Composition  knob  and  pointer. 

One  piece  spring  brass  4"xl-2"x014". 

One  brass  rod,  1-4"  Round  3"  long. 

One  piece  thin  bristol  board  (for  scale). 

Miscellaneous  screws,  nuts,  wire,  solder 
and  washers. 

Slide  Wire  Parts 

One  disk,  seven  inches  in  diameter, 
one-half  inch  thick,  will  be  required, 
(Detail  1).  This  will  be  turned  from  a 
piece  of  white  maple,  or  other  close 
grained  hard  wood.  A  groove,  or  track 
for  a  3-16"  ball,  will  be  cut  around  the 
edge  as  shown  in  detail  1.  This  groove 
will  be  one-sixteenth  of  an  inch  deep. 

One  hole,  five-sixteenths  of  an  inch 
in  diameter  will  be  drilled  in  the  exact 
center  to  pass  the  1-4"  shaft,  and  four 
holes  will  be  drilled  to  pass  a  No.  6 
brass  machine  screw,  and  counter-bored 
to  receive  a  No.  6  brass  hexagon  nut. 
These  four  holes  will  line  up  with  the 
four  holes  to  be  drilled  later,  in  the  panel 
(Detail  3)  and  will  be  used  for  mounting 
the  disk  to  the  panel. 

One  brass  rod,  one  quarter  of  an  inch 


18 


RADIO  AGE  for February,  1925 


The  Magazine  of  the  Hour 


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in  diameter  and  about  three  inches  long, 
will  be  threaded  to  receive  a  one-quarter 
inch  brass  hexagon  nut,  over  its  entire 
length.  Two  brass  washers  and  six, 
one-quarter  inch  brass  hexagon  nuts 
will  be  secured,  to  fit  this  rod. 

One  composition  knob  will  be  drilled 
and  counterbored  to  receive  the  1-4" 
shaft,  and  shall  have  a  pointer,  three  or 
three  and  one-half  inches  long,  fastened 
to  the  bottom,  (see  figures  2  and  3). 
A  pointer  can  be  made  from  spring 
brass  .014  inch  in  thickness  if  required. 

When  all  of  the  above  parts  have 
been  made  or  secured,  the  next  step  will 
be  to  prepare  the  panel. 

Drilling  the  Panel 

A  COMPOSITION  panel  8"x8"x3-16", 
thick  will  be  prepared,  and  the 
drillings  centered  as  shown  in  detail  3. 
One  hole  5-16"  in  diameter 
will  be  drilled  in  the  exact 
center,  to  pass  the  1-4" 
shaft.  Four  holes  will  be 
drilled  and  tapped  to  receive 
No.  4  Round  head  brass 
machine  screws  to  mount 
the  scale,  and  eight  holes  to 
pass  No.  8  Machine  screws 
will  be  drilled,  two  in  each 
corner,  to  mount  the  binding 
posts  XI,  X2,  Yl,  Y2,  Rl, 
R2,  Positive  and  Negative. 
Suitable  mounting  holes  will 
then  be  drilled  to  fit  the  cab- 
inet used,  and  the  panel  will 
be  laid  aside. 

An  induction  coil  or  open 
core  transformer  may  be  pur- 
chased from  any  reliable  elec- 
trical supply  house,  for  about 
one  dollar,  or  it  may  be  made 
at  an  even  smaller  expense. 

One  bundle  of  soft  iron 
wire  having  a  total  diameter 
of  about  three-eighths  of  an 
inch  and  a  length  of  four 
inches  will  be  securely  tied, 
and  wrapped  with  about  ten 
turns  of  good  wax  paper. 
Two    pieces    of    wood,    one-  Fig.  2 A 


quarter  inch  thick  and  one  and  one- 
half  inches  square,  will  have  a  three- 
eighths-inch  hole  drilled  in  the  centers, 
and  the  core  ends  made  secure  in  these 
holes,  making  an  iron  core  spool. 

Shellac  or  glue  may  be  used  to  fasten 
all  parts,  and  it  would  be  well  to  tie 
the  windings  with  shellac  or  glue  when 
each  coil  is  completed. 

The  primary  coil  will  be  wound  in 
even  layers,  directly  over  the  core,  on 
the  wax  paper  wrappings.  Two  hundred 
turns  of  No.  20  double  cotton  covered 
magnet  wire  will  be  required  and  both 
ends  of  this  winding  will  be  brought  out 
through  holes  in  one  of  the  end  pieces 
of  the  spool,  and  the  entire  coil  covered 
with  about  six  turns  of  wax  paper,  thus 
completing  the  primary  coil. 

The  secondary  coil  will  be  wound 
directly   over   the   primary   coil   and   on 


top  of  the  wax  paper. 
Be  careful  to  wind  the 
wire  in  the  same  di- 
rection as  was  done 
on  the  primary  coil. 
Six  hundred  turns  of 
No.  30  double  cotton 
covered  wire  will  be 
necessary,  bringing 
each  end  of  the  coil 
out  through  holes  in 
the  end  piece  opposite 
to  the  primary  leads. 
It  would  be  well  to 
splice  a  piece  of 
heavier  wire  to  the 
secondary  coil  ends, 
taking  two  or  three 
turns  and  bringing 
out  through  the  end 
piece,  as  No.  30  wire 
is  rather  delicate  and 
hard  to  handle. 

Ten  turns  of  wax 
paper    will    then    be 
wound    around    the 
coil    and    made  fast, 
completing  the  induction  coil. 

A  high  frequency  buzzer  (900  to  1,000 
cycles)  can  be  secured  from  any  reliable 
dealer.  It  should  be  enclosed  under  a 
metal  cover.  A  buzzer  of  this  type  is 
required  to  set  up  a  current  whose  fre- 
quency is  somewhere  near  the  frequency 
of  voice  currents,  to  better  balance  and 
measure  equipment  subject  to  voice 
frequency  currents. 

Assembly  of  the  Parts 

r  I  ''HE  first  step  in  assembling  the  parts 
-*-  of  the  slide  wire  should  be  to  fasten 
the  No.  34  German  silver  resistance 
wire   in    place   on    the    disk    (Detail    1), 


itKiA 


but  it  would  be  well  to  assemble  the 
parts  to  try  them  out  for  fit  and  per- 
formance first,  and  then  remove  such 
pieces  as  necessary  to  put  the  resistance 
wire  in  place,  as  it  is  very  delicate  and 
can  be  damaged  easily. 

The  1-4"  shaft  will  be  made 
fast  through  the  center  hole 
in  the  disk,  (Detail  1)  using 
two  washers  and  two  hexa- 
gon brass  nuts,  (Figure  2). 
When  it  has  been  adjusted 
so  as  to  revolve  freely,  lock 
the  nuts  onto  the  shaft  with 
a  small  center  punch,  so  that 
they  will  not  turn  loose  or 
tighten  with  the  shaft  when 
it  is  revolved.  Then  mount 
the  disk,  (Detail  1)  to  the 
panel,  with  No.  6  flat  head 
brass  machine  screws  and 
nuts,  as  shown  in  Figure  2, 
using  washers  to  space  the 
disk  so  that  the  nut  on  top 
of  the  disk  will  clear  the  panel 
by  at  least  one-sixteenth  of 
an  inch. 

When  the  disk  is  mounted 
to  the  panel,  the  contact  arm 
(Detail  2)  will  be  made  fast 
to  the  shaft  under  a  1-4" 
brass  hexagon  nut,  (see  Fig- 
ure 2)  and  the  flange  bent  so 
as  to  exert  a  tension  on  the 
3-16"  ball,  but  not  enough 
— Showing  the  drillings  in  the  8"x8"x3-16"  panel.  to  impair  the  travel  of  this 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


19 


ball  in  the  groove  or  track  on  the  edge 
of  the  disk. 

The  panel  and  slide  wire  will  now  be 
laid  aside  and  the  induction  coil  and 
buzzer  mounted  into  the  cabinet  as 
shown  in  Figure  3.  When  this  has  been 
done,  the  instrument  is  ready  to  be 
■  wired  and  will  be  set  aside  until  the 
scale  is  made  and  mounted  to  the  panel. 
The  Scale 

The  piece  of  bristol  board  for  the 
scale  will  be  cut  into  a  disk  seven  inches 
in  diameter,  and  will  have  a  one-half 
inch  hole  directly  in  the  centre  to  fit 
over  the  1-4"  shaft,  when  mounted  on 
the  panel.  Four  holes  will  be  cut  to 
pass  the  No.  4  brass  machine  screws 
for  mounting,  and  the  scale  laid  out. 

Black  India  ink  is  the  best  to  use  on 
account  of  its  being  water-proof,  and 
will  stand  wear  better  than  other  inks. 
Also,  it  will  not  blur  once  it  is  dry,  and 
it  will  stand  out  clearly. 

The  scale  will  have  one  hundred  sec- 
tions on  each  side  of  "O"  (See  Figure  2). 
To  lay  this  out,  first  measure  the  sections 
one  inch  long  around  the  circumference 
of  the  disk  each  way,  from  a  point  to 
represent  "O,"  then  divide  each  of  these 
sections  into  ten  equal  parts,  and  number 
from  0  to  100,  to  the  left  of  "O"  and 
from  0  to  100  to  the  right  of  "O." 

A  partial  scale  is  shown  in  Figure  4, 
to  exact  size,  and  may  be  used  as  a 
guide  in  spacing  all  of  the  sections  if 
desired. 

When   the   scale   has   been   completed 
it  will  be  mounted  to  the  panel  by  four 
No.  4  round  head  brass  machine  screws 
in  the  position  shown  in  Figure  3. 
Wiring  the  Instrument 

TWO  No.  4  round  head  wood  screws 
will  be  put  on  the  disk,  one  directly 
under  the  100+  and  one  directly  under 
100—  points  on  the  scale.  Placed  so 
that  when  the  knob  is  turned,  as  far 
as  it  will  go  in  each  direction,  the  ball 
will  be  directly  under  the  end  of  the 
scale  and  the  pointer  will  be  at  100  + 
or  100 -. 

Three  terminals  will  be  put  under 
each  screw  and  the  screw  tightened  to 
make  a  good  contact.  Now  take  the 
No.  34  German  silver  wire,  and  place 
it  around  the  groove,  laying  tight  on  the 
bottom  and  make  fast  to  one  of  the 
terminals  on  each 
screw. 

A  pig-tail  connec- 
tion will  be  made 
fasttothel-4"shaft, 
as  shown  in  Figure  2 
and  connected  to 
binding  post  Rl. 

One  lead  from  the 
primary  of  the  in- 
duction coil  will  be 
made  fast  to  one  ter- 
minal of  the  buzzer, 
and  the  remaining 
primary  lead  con- 
nected to  post  — , 
using  stranded  wire. 
Now  connect  the  re- 
maining terminal  of 
thebuzzertopost+. 

The  secondary 
leads  of  the  indue- 


P/)£T/#L      SCALE 

tion  coil  will  then  be  connected,  one  to 
each  stop  screw  on  the  disk  (Detail  1) 
using  one  of  the  terminals. 

Binding  post  X2  will  be  connected 
to  stop  screw  under  100—  on  the  scale 
and  post  Y2  to  the  stop  screw  under 
100+  on  the  scale,  using  the  remaining 
terminal  on  each. 

Binding  post  Yl  and  XI  will  be  con- 
nected to  post  R2  and  the  panel  fastened 
to  the  cabinet,  completing  the  instru- 
ment. 

Operation 

Connect  a  receiver  to  terminals  Rl 
and  R2  (Figure  1)  and  the  positive  side 
of  a  six  volt  battery  to  post+  and  the 
negative  side  to  post—.  Connect  the 
transformers  or  condensers  to  be  meas- 
ured or  balanced  to  posts  XI  and  X2 
and  to    posts    Yl    and    Y2,    as    follows: 


SlD£    ELEV/iTtOH. 


r/G.  3. 


EQUIPMENT. 


Balancing  R.  F.  Transformers 

Connect  the  inside  terminal  of  one 
primary  coil  to  post  XI  and  the  ouiside 
terminal  to  post  X2.  Connect  the  inside 
terminal  of  the  other  primary  coil  to 
post  Yl  and  the  outside  terminal  to 
post  Y2. 

Move  the  slide  wire  pointer  until  no 
hum  is  heard  in  the  head  phones.  If 
the  silent  period  is  at  "O,"  the  coils 
are  balanced;  if  the  pointer  is  at  10  — 
it  will  indicate  that  coil  X  has  more 
impedance  than  coil  Y,  and  it  will  be 
necessary  to  add  turns  to  coil  Y  until 
the  pointer  shows  "O"  as  the  silent 
spot. 

If  the  pointer  shows  10+  as  the 
silent  spot,  then  coil  Y  has  more  im- 
pedance than  coil  X  and  to  balance 
remove  turns  until  the  pointer  shows 
"O"  as  the  silent  period. 

Repeat  the  operation  for  the  secondary 
coils  of  the  transformer,  connecting 
them  in  the  same  manner  to  posts  XI, 
X2  and  Yl  and  Y2. 

When  three  or  more  transformers 
are  to  be  balanced,  use  the  transformer 
connected  to  XI  and  X2  terminals  as 
the  master  and  balance  coils  con- 
nected to  Yl  and  Y2  to  equal.  If  the 
three  transformers  are  thus  balanced 
or  matched,  they  will  all  fall  within  a 
few  meters  of  one  another  and  should 
work  well  together. 

To  Measure  Impedance  or 
Resistance 

WHEN  it  is  desired  to  measure  the 
impedance  of  a  coil,  it  will  be  neces- 
sary to  secure  a  master  coil  or  impedance 
whose  impedance  is  known;  say  1  henry 
for  example.  This  master  impedance  coil 
will  be  connected  to  postsXl  and  X2. 

The  coil  to  be  measured  will  then 
be  connected  to  posts  Yl  and  Y2  and 
the  slide  wire  revolved  to  the  silent 
point.  If  this  should  fall  on  25—  then 
the  impedance  of  coil  Y  will  be  .25  less 
than  1  henry  or  .75  henry,  or  if  it  should 
stop  at  50—  coil  Y  will  be  .50  less  than 
coil  X  or  '.5  henry,  or  wherever  it  stops 
on  the  —  side  of  the  scale,  the  reading 
will  be  direct.  Thus,  if  it  should  stop 
at  86,  the  coil  Y  will  be  .86  less  than 
coil  X  or  14  per  cent  of  coil  X. 

When  the  reading  comes  on  the  + 
side  of  the  scale,  coil  Y  will  be  greater 
than  coil  X.  Thus, 
if  the  pointer  shows 
25+,  then  the  im- 
pedance of  coil  Y 
will  be  1.25  of  coil 
X  or  1.25  henry,  or 
if  it  should  stop  on 
86,  the  coil  Y  would 
be  1.86  henry. 

Resistance  will  be 
found  in  the  same 
manner.  Attaching 
a  coil  whose  resist- 
ance is  known  to 
terminals  XI  and 
X2,  and  the  un- 
known to  terminals 
Yl  and  Y2,  then  the 
resistance  in  ohms 
will  be  proportional 
to  coil  or  resistance 
(Turn  to  page  73) 


20 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


^Exploding  a   Few  Antiquated   Theories 

Don't  Worry 

bout 

Antennas 


WISHING  to  know  the  up-to-date 
truth  about  antennas,  and  their 
relation  to  the  new  receiving 
sets  and  results,  I  asked  Dr.  Dellinger, 
Chief  of  the  Radio  Laboratory  of  the 
United  States  Bureau  of  Standards,  for 
information.  The  experts  at  the  Bureau 
of  Standards  are  not  in  the  business  of 
making  or  selling  apparatus.  They 
have  exceptional  opportunities  for  test- 
ing theories,  parts,  sets  and  appliances. 
When  they  speak,  they  speak  with 
authority  and  without  such  prejudice 
as  a  man  with  a  dollar  at  stake  may  be 
inclined  to  yield  to. 

Dr.  Dellinger  promptly  smashed  sev- 
eral pet  theories  and  erroneous  notions 
about   antennas   that   have  been   widely 


believed.  He  spoke  of  the  number  of 
persons  who  wanted  radio  sets  but  who 
refrained  from  installing  them  because 
they  believed  that  the  antenna  was 
dangerous,  troublesome,  and  compli- 
cated. In  fact,  he  said  the  antenna  is 
none  of  these  things. 

The  advertising  of  "antennaless"  radio 
sets  has  caught  the  fancy  of  many  cus- 
tomers. Dr.  Dellinger  says  there  "ain't 
no  such  animal,"  though  not  in  exactly 
those  words.  He  himself  predicted  long 
ago  that  there  would  be  and,  in  one 
sense,  they  arrived,  but  every  radio 
receiver  must  have  an  antenna  of  some 
sort,  'even  though  it  may  be  but  a  few 
turns  of  wire  concealed  in  the  cover  of 
its  cabinet.  To  get  power  from  the  radio 
waves  without  an  antenna  is  as  impos- 
sible as  getting  lemonade  from  a  lemon 
without  some  kind  of  a  squeezer.  Just 
as  a  cow  may  be  milked  by  a  milk  maid, 
farm  hand,  vacuum  suction  outfit  or  a 
calf,  so  radiated  electrical  energy  may 
be  drawn  from  the  ether  by  various 
means,  but  whatever  the  extractor  is, 
it  is  an  antenna. 

Antennas  are  Liberal 

A/rOST  anything  will  work,"  said 
-L'J-  Dr.  Dellinger  of  antennas.  "You 
can't  go  wrong.  You  can  take  directions, 
giving  in  minute  detail  the  height,  size, 
mode  of  fastening  and  insulating  the 
antenna,  and  work  a  week  following 
these  directions,  and  then  walk  into  the 
home  of  a  friend  and  find  him  getting 
perfectly  good  results  with  a  wire  tacked 
up  to  the  picture  moulding.  None  the 
less,  a  fairly  long  and  high  antenna,  out- 
of-doors,  is  the  cheapest  way  to  get  loud 
signals  with  the  simplest  radio  sets. 

Have  you  worried  about  length,  num- 
ber of  wires,  insulated  or  bare  wire? 
His  suggestion,  like  that  of  the  physician 
to  the  patient  who  had  read  the  patent 
medicine  ad  and  begun  to  feel  the  symp- 
toms is:  "Don't  worry!"  The  neigh- 
bor's multiple-wire,  flat-top  or  cage 
antenna  probably  has  a  transmitting 
amateur  at  the  end  nearest  hell.  A 
receiving  antenna  should  simply  be  a 
wire  running  from  the  receiving  set  to 
as  high  a  point  as  possible  at  the  far  end. 
A  single,  continuous  wire  is  better  than 
an  out-door  and  an  indoor  portion  joined 
together.     It  does  not  need  to  be  hori- 


By 

ARMSTRONG 

PERRY 


zontal.  Just  let  it  take  any  angle  that 
happens  as  a  result  of  the  height  of  the 
farther  point  of  support. 

Some  have  believed  that  "directional 
effects"  in  an  antenna  affect  results,  in 
spite  of  the  fact  that  ships  at  sea  do  not 
turn  broadside  on  or  stern  to  the  shore 
station  when  sending  and  receiving 
messages.  Dr.  Dellinger  says,  comfort- 
ingly, that  the  fears  that  our  antennas 
will  not  receive  signals  from  one  direc- 
tion or  another  are  entirely  groundless. 
Perceptible  differences  due  to  direction 
are  obtainable  only  with  special  an- 
tennas much  longer  than  those  used 
for    broadcast    reception. 

In  discussing  insulation,  he  confirmed 
some  popular  impressions  and  brought 
up  other  matters  that  are  often  over- 
looked. Porcelain  or  glass  insulators 
should  be  used  to  support  the  antenna, 
he  said,  and  it  should  be  kept  as  far  as 
possible  from  all  other  objects,  such  as 
buildings  or  trees.  Its  length  should 
extend  over  clear,  unobstructed  ground. 
Except  where  it  enters  the  building 
through  a  porcelain  tube,  and  goes  direct 
to  the  receiving  set  without  touching 
walls  or  anything,  it  should  be  kept 
more  than  five  feet  from  any  object. 

Stranded  antenna  wire  has  been  ad- 
vised many  times  because  of  its  greater 
surface  as  compared  with  its  size.  Dr. 
Dellinger  says  it  is  not  quite  as  good  as 
solid  copper  wire,  No.  14  or  larger,  be- 
cause its  resistance  is  higher.  The  ob- 
ject of  all  the  effort  to  keep  the  antenna 
away  from  everything  is  to  lower  the 
resistance.  The  stranded  wire,  however, 
is  stronger  mechanically.  Insulated 
antenna  wire  helps  us  to  spend  more 
money  but  not  to  secure  more  energy 
from  the  radio  waves. 

Regulating  the  Length 

\  S  TO  length,  this  expert  says  any- 

-^*-  where    from    50    to    150    feet    gives 

good   results.      Lengthen    the   wire   and 

(Turn  to  page  69) 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


21 


The  WHY  of  Vacuum  TUBES 

Frank  Pearne 
Takes  You  Into 


Knowing 
About  Tubes 


Will  Help  Set- 
Builder  Get 
Results 


JUST  what  part  the  vacuum  tube 
plays  in  the  working  of  a  receiving 
set  is  well  known  to  all  radio  enthu- 
siasts; at  least,  they  know  that  if  it  is 
to  be  used  as  a  detector  tube,  it  must 
be  placed  in  one  part  of  the  circuit  and 
if  it  is  to  be  used  as  an  amplifier  tube, 
it  is  used  in  a  different  part  of  the  circuit. 

They  also  understand  in  a  way  that 
when  used  as  a  detector,  its  rectifying 
qualities  are  pushed  to  the  limit  and 
when  they  are  used  in  the  amplifying 
circuit,  they  must  be  so  arranged  that 
their  amplifying  qualities  are  brought 
to  maximum. 

Many  fans  have  gone  far  deeper  into 
the  subject,  but  there  are  a  great  many 
who  care  only  for  the  music  and  pleasure 
which  the  set  affords  and  do  not  attempt 
to  find  the  reason  that  a  tube  is  necessary 
in  the  set,  but  where  we  find  one  of  this 
type,  we  find  a  thousand  of  the  other, 
who  are  eager  to  learn  more  about  the 
mysteries  of  radio,  thirsting  for  more 
knowledge  and  getting  the  keenest 
delight  out  of  building  their  own  appar- 
atus and  knowing  just  why  it  produces 
the  results  obtained. 

It  is  for  these  hard  workers  and  con- 
tributors to  the  radio  science  that  this 
article  is  written,  in  the  hope  that  it 
may  be  of  some  service  to  them.  It 
will  in  a  measure  also  serve  to  answer 
the  many  thousands 
of  questions  per- 
taining to  the  value 
of  the  many  new 
types  of  vacuum 
tubes  which  have 
lately  been  put  on 
the  market. 

A  Tube  is  Peculiar 

r|',HE  workings  of 
•*-  a  tube  are  pecu- 
liar to  say  the  least, 
as  its  action  depends 
upon  what  is  known 
as  the  evaporation 
of  metal.  Many 
will  wonder  at  this 
statement,  as  the 
evaporation  of  fluids 
may  be  well  under- 
stood, but  it  is  hard 
torealizethat  metals 
may  do  the  same 
thing  although  not 
in  a  molten  condi- 
tion. It  is  true  that 
they  evaporate  very 


slowly  within  the  ordinary  range  of 
temperatures,  but  when  heat  is  applied, 
this  rate  of  evaporation  increases  rapidly. 

Air,  however,  has  an  oxidizing  effect 
upon  this  action,  and  when  surrounded 
by  air,  it  will  usually  oxidize  before  any 
great  amount  of  evaporation  can  be 
noticed.  If,  then,  the  metal  can  be 
placed  in  a  vacuum  and  heat  applied 
in  some  manner,  it  will  slowly  evaporate 
until  it  disappears. 

When  an  ordinary  tungsten  lamp 
begins    to    show    signs    of    age    and    the 


CouPLER, 


GRID  CONDENSER- 
AND  LEAK. 


THREE  ELEM- 
ENT TUBE. 


♦I'l'l'r 

PLATrBAT. 


The  three  element  tube  used  as  a  detector 


Mysteries  of 

New  Types  of 

Tubes 


light  becomes  poor,  a  close  examination 
will  show  that  the  inside  of  the  glass 
bulb  is  coated  with  a  dark  material 
which  is  nothing  more  or  less  than  the 
tungsten  which  has  evaporated  from  the 
filament.  In  explaining  the  cause  for 
this,  it  will  be  necessary  to  know  some- 
thing about  the  electron,  which  is  the 
smallest  known  particle  of  matter.  All 
matter  is  composed  of  atoms  which  are 
made  up  of  electrons  whirling  in  different 
orbits  around  a  central  nucleus  of  posi- 
tively charged  protons  and  negatively 
charged  electrons,  which  cling  together. 
The  electron  is  always  negatively 
charged,  and  in  fact  is  spoken  of  as  the 
smallest  possible  quantity  of  negative 
electricity.  The  normal  atom  does 
not  exhibit  any  electrical  charge,  the 
reason  being  that  it  has  acquired  enough 
electrons  to  neutralize  the  positive 
charge,  which  it  has  by  nature  of  its 
structure;  but  if  it  loses  one  electron, 
then  the  positive  charge  asserts  itself 
and  if  it  gains  one  electron,  it  becomes 
a  negative  atom.  In  other  words,  the 
addition  or  subtraction  of  one  electron 
changes  it  from  a  normal  atom  having 
no  apparent  charge  to  one  having  either 
a  positive  or  negative  charge.  If  the 
atom  becomes  positive  because  of  the 
loss  of  one  electron,  it  will  again  become 
neutral  if  it  regains  another  electron. 
Different  kinds  of 
matter  are  made  up 
of  atoms  which  have 
different  numbers 
of  protons  and  elec- 
trons for  a  nucleus 
and  more  or  less 
floating  electrons. 

The  Hydrogen 
Atom 

FOR  example,  the 
hydrogen  atom, 
which  is  the  most 
simple  of -all,  is  com- 
posed of  one  single 
electron  revolving 
around  a  proton, 
while  the  tungsten 
atom  is  much  more 
complex  as  it  con- 
sists of  seventy-four 
electrons,  whirling 
around  a  nucleus  of 
about  200  positive 
protons  tightly 
clingingtoabout  100 
electrons.  Now,  un- 


22 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


AERIAL. 


der  ordinary  con- 
ditions the  elec- 
trons which  go  to 
make  up  one  atom 
of  a  certain  matter 
stay  within  their 
own  orbits  and  do 
not  fly  off  to  join 
■another  atom,  but 
it  has  been  found 
that  in  those  ma- 
terials which  are 
conductors  of  elec- 
tricity, one  elec- 
tron in  each  atom 
is  more  or  less  free 
and  will  stray 
around  among  the 
other  atoms,  some- 
times clinging  to 
one  and  then  to 
another,  while  in 
those  materials 
which  are  known 
as  good  insulators, 

they  stay  within  their  own  orbits  and  do 
not  wander  about. 

If  an  electrical  conductor  is  connected 
between  some  two  points  having  a  differ- 
ence of  potential,  such  as  a  battery  or 
a  dynamo,  those  electrons 
which  are  free,  being  really 
negative  charges  of  elec- 
tricity, will  naturally  be 
attracted  toward  the  point 
which  is  positive  (the  car- 
bon terminal  of  the  battery, 
or  the  positive  terminal  of 
the  dynamo)  and  will  grad- 
ually work  themselves  along 
between  the  atoms  from 
one  end  to  the  other,  thus 
producing  what  is  known  as 
a  flow  of  electric  current. 
But  it  should  here  be  noted 
that  the  slow  movement  of  the  electrons 
is  in  the  opposite  direction  to  that  of 
which  we  consider  the  direction  of  the 
current. 

Now,  just  what  takes  place  in  the 
vacuum  tube?  Some  years  ago  it  was 
discovered  that  if  a  piece  of  metal  was 
heated  in  a  gas  flame  and  another  piece 
of  metal  was  placed  near  it  and  given 
a  positive  charge,  some  of  these  free 
electrons  in  the  heated  metal  would  be 
attracted  from  the  hot  metal  to  the  cold 
positively  charged  metal  through  the 
intervening  space,  passing  from  this 
cold  metal  through  an  electrical  con- 
ductor back  to  the  heated  metal.  The 
emission  of  electrons  from  the  heated 
metal,  however,  was  not  very  great, 
because    the     metal     became     oxidized, 


VARIABLE 
COND. 


flLhMWT. 


mm 

PLPtTE  BaT. 

PHONES. 


F'tL.BAT. 


Hydrogen  atom,  showing  the 
electron  whirling  around  the 
proton. 


Electrons  attracted  to  cold  plate,  when  it  is 
given  a  positive  charge. 


The  two  element  vacuum  tube  used  as  a  detector. 


forming  a  coating  over  the  hot  metal, 
which  served  as  a  barrier  to  the  flow  of 
electrons  and  only  a  few  of  them  could 
force  their  way  through.  When  an  elec- 
trically heated  filament  was  used  and 
was  enclosed  with  the  cold 
plate  in  a  vacuum,  the  flow 
was  greatly  increased. 

Surface  Freed  of  Coating 

DY  REMOVING  all  the 
-*-'  air  from  the  interior 
of  the  glass  bulb,  which 
contains  the  filament  and 
the  cold  piece  of  metal 
(called  the  plate)  the  fila- 
ment does  not  oxidize,  thus 
leaving  the  surface  free  of 
any  hard  coating  which 
might  be  difficult  for  the 
electrons  to  break  through. 
It  also  removes  most  all  of 
the  gasses,  which  is  another 
important  factor,  as  the 
mass  of  the  electron  is  so 
small  that  should  it  collide 
with  an  atom  of  gas  as  it 
moves  outward  from  the 
filament,  it  would  immedi- 
ately bounce  back  to  it  and 
would  never  reach  the  plate. 
Then,  too,  the  hot  filament 
has  a  tendency  to  absorb 
gas,  and  too  much  of  this 
absorption  may  stop  the 
electron  flow  entirely.' 

One  peculiar  fact,  however,  has  been 
proven.  That  is  that  although  certain 
impurities  in  the  outside  surface  of  the 
filament  have  a  tendency  to  prevent 
the  escape  of  the  electrons,  certain  oxides, 
when  spread  over  the  surface  of  the 
filament,  will  cause  a  great  increase  in 
the  number  of  electrons  emitted  from  it. 
Ordinarily  a  tungsten  filament  would 
have  to  be  heated  to  nearly  a  white 
heat  to  throw  off  the  maximum  number 
of  electrons,  but  with  the  proper  coating 
of  certain  oxides,  the  same  thing  may 
be  accomplished  at  a  very  low  temper- 
ture.  In  fact,  the  temperature  required 
is  so  low  that  it  will  sometimes  hardly 
make  the  filament  glow.  However, 
great  care  must  be  used  in  the  use  of 
coated  filaments,  as  too  much  heat  will 


An  atom  composed  of  severed 
protons  and  Electrons  clinging 
together. 


ruin  the  oxide  coating  and  hence  reduce 
the  efficiency  of  the  tube. 

It  must  also  be  remembered  that 
although  many  electrons  may  start  on 
the  journey  from  the  filament  to  the 
plate,  the  number  which  finally  reach 
it  is  few  compared  to  the  number  which 
start.  Those  which  do  not  cover  the 
entire  distance  fall  back  into  the  hot 
filament  for  reasons  which  will  be  ex- 
plained later.  The  coated  filament, 
then,  has  proven  to  be  a  great  improve- 
ment in  the  vacuum  tube,  and  as  this 
is  a  secret  process,  it  is  a  question  as  to 
whether  or  not  some  of  the  new  tubes 
which  have  appeared  on  the  market 
since  the  expiration  of  certain  patents 
are  using  it;  but  there  can  be  no  doubt 
about  the  results  which  some  of  them 
produce,  as  many  of  them  make  excellent 
detectors  and  amplifiers.  But  the  ques- 
tion of  their  useful  life  is  the  most  vital 
point  to  be  considered  and  only  time 
will  tell. 

"The  Edison  Effect" 

NOW  we  have  seen  how  the  emission 
of  the  electrons  from  the  filament 
flow  to  the  positively  charged  plate,  but 
nothing  has  been  said  as  to  why  such 
an  arrangement  can  be  used  as  a  rectifier 
of  high  frequency  currents  as  used  in 
the  radio  receiver,  and  also  the  low  fre- 
quency currents  which  are  used  in  charg- 
ing batteries  from  the  ordinary  60  cycle 
alternating  elecfric  lighting  circuit.  This 
is  what  is  known  as  the  "Edison  effect" 
because  Edison  was  the  first  to  discover 
that  if  the  positive  terminal  of  a  battery 
was  connected  to  the  cold  plate  and  the 
negative  to  the  filament,  the  electrons 
which  came  in  contact  with  the  plate 
would  continue  their  travels  through  the 
plate,  over  the  connecting  wire  and  back 
to  the  filament,  to  be  passed  on  again  to 
the  plate. 

A  galvanometer  placed  in 
this   circuit  showed   that   a 
current    was  flowing  in  the 
opposite     direction    to    the 
movement  of  the  electrons, 
but    that    if    the    terminals 
of  the  battery  were  reversed, 
no  current  would  flow.     Ed- 
ison probably  never  realized 
the  value  of  this  discovery, 
as  it  remained  for  Dr.  Flem- 
ing to  make  the   first  prac 
tical    use  of   it    some  years 
later.     The  reason  the  cur- 
rent  will   only  pass  in  one 
direction    through    the    circuit    is     now 
quite    plain,    as    the    positive   terminal 
of  the  battery  connected    to    the  plate 
(Turn  to  page  67) 


COLD  PLhTC. 


B/irrfffY. 


£V~ 


m. 


FOMENT    BAT. 


\l 


3  PLATE 

PLATE  t    3hT 


j< 


Electron  emission  from  heated  filament  to 
cold  positively  charged  plate. 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


23 


URayG 

Piety 
Offers 


A  Four  Tube 

LOW  LOSS 

^-Circuit 

Tuner 


A  Novel 
Hookup  that 
Will  Tune  DX 
Right  Through 
Local   Stations: 
Addition  of  R.F. 
Stage  Gives  More 
Range,    Selectivity 


WITH  the  steady  increase  in  power 
of  the  broadcasting  stations,  the 
demand  for  an  economical  and 
sensitive  receiver  has  become  more  and 
more  urgent.  At  first  the  stations  were 
of  limited  power  and  few  and  far  between. 
Today  our  large  cities  -  usually  have 
several  stations  operating  at  the  same 
time. 

The  degree  of  selectivity,  even  though 
the  .apparatus  is  of  the  best  design 
possible,  is  limited  when  operating  under 
these  conditions^  -If  a  station. is  using 
suffieieH-t-^power,  it  can  -spread  itself 
over  the  dials  of  any  set  using  only  one 
or  two  tuned  circuits.  If  the  coupling 
is  made  weak  enough  to  make  the  nearby 
stations  sharper,  the  ..volume  .  oa  .  the 
weaker. and   more   distant  stations  falls 


off  to  such  an  extent  that  reception  is 
difficult  and   unsatisfactory. 

The  "trick"  circuit  has  passed  on  and 
the  three-circuit  tickler  feedback  arrange- 
ment using  low-loss  apparatus  is  probably 
the  most  popular  set  today.  It  justly 
holds  this  position,  for  it  has  a  high  de- 
gree of  sensitivity  with  good  volume  and 
selectivity.  The  popularity  of  low-loss 
three-circuit  tuners  satisfies  the  greatest 
numbers  as  possessing  most  of  the 
qualities  necessary  to  a  good  receiver. 
Unless  the  owner  of  such  a  receiver  is 
particularly  fortunate  in  his  location, 
even  the  best  apparatus  will  not  enable 
him  to  cut  out  nearby  stations.  For 
him  who  cannot  change  his  location, 
about  the  only  thing  that  can  be  done 
is  to.  change  his  circuit. 


A  MONG  the  better  grade  of  low-loss 
-<- *-  tuners  on  the  market  the  degree  of 
selectivity  is  not  very  different.  The  fun- 
damental regenerative  may  be  used  with 
the  majority  of  such  tuners;  circuit 
shown  on  page  25.  This  circuit  has  a  great 
many  desirable  characteristics  and  is 
as  good  as  any,  all  things  considered, 
for  a  one,  two  or  three  tube  set. 

Only  Two  Controls 

There  are  only  two  controls,  one  for 
regeneration  and  one  for  wavelength. 
The  primary  is  untuned  and  may  be 
adjustable,  permitting  a  reasonable  bal- 
ance between  volume  and  selectivity. 
Now,  if  we  take  an  efficient  detector 
and  add  to  it  a  stage  of  radio  in  such  a 
manner  that   its  original  characteristics 


24 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


are   retained,    we   should    materially   in-     fixed     condenser     across     the     phones, 
crease   the   most   desirable   properties  of     However,  this  very  often  will  cause  the 


the  set,  without  adding  complicating 
and  undesirable  features.  In  adding 
this  stage  of  radio  frequency  amplifica- 
tion, we  will  at  one  and  the  same  time 
make  the  set  more  selective,  more 
sensitive,  and  decrease  the  amount  of 
objectionable  radiation  to  a  negligible 
quantity. 

The  circuit  shown  below  is  adapted 
to  practically  any 
type  of  tuner  us- 
ing the  regular 
three  circuit  hook- 
up. It  is  shown 
on  a  panel 
7"x24",  although 
any  reasonable 
layout  may  be 
used.  It  is  best, 
however,  to  line 
up  your  set  some- 
what as  illustrated, 
making  sure  that 
the  air-core  trans- 
f  or  mer  T-  1  is 
placed  at  right 
angles  to  the 
tuner  T-2. 

In     wiring    the 
were      run     direct, 


detector  to  oscillate  too  readily  and 
thereby  make  tuning  more  difficult. 
The  first  stage  of  audio  may  also  be  used 
for  loud  speaker  reception  on  local  signals 
in  cases  where  extreme  volume  is  not 
necessary. 

Exact  Settings  Necessary 

THE    regular    type    of    low-loss    con- 
denser  was   not   used,   as   the   writer 


A  panel  view  of  the  three-circuit  regenerator.  There  are  three  tuning  controls,  and 
three  rheostats.  Tuning  is  very  selective,  KGO,  at  312  meters,  being  brought  in  while 
WSAI,  at  309  meters,  was  going  full  blast.    And  thsre  was  no  interference. 


set,  all  the  wires 
making  consider- 
able shorter  leads  than  would  be 
obtained  if  it  were  constructed  in  the 
conventional  manner.  Direct  leads  are 
always  more  desirable,  although  not  so 
neat  in  appearance.  The  undesirable 
capacity  feedback  between  leads  is  cut 
down  by  shortening  them  in  this  manner. 
No  jack  was  used  by  the  writer  in 
the  detector  circuit,  as  this  is  not  gen- 
erally of  value  to  anyone  of  reasonable 
experience,  as  on  very  weak  signals  it 
is  best  to  listen  in  on  the  first  stage  of 
audio.  This  eliminates  the  difficulty 
often  experienced  in  a  regenerative  set 
of  tuning  in  on  the  detector  and  have 
the  signal  disappear  when  placed  on 
the  loud  speaker.  The  change  in  feed- 
back in  the  detector  circuit  caused  by 
changing  from  phones  to  loud  speaker 
is  generally  eliminated  by  using  a  large 


could  not  find  any  with  the  positive 
vernier  action  absolutely  necessary  in 
this  circuit.  It  is  doubtful  whether  the 
difference  between  good  average  conden- 
sers and  the  most  efficient  condensers 
possible  would  compensate  for  the  loss 
of  a  good  vernier  action.  Geared 
arrangements  having  back-lash  are  worse 
than  none  at  all.  The  tuning  is  so  sharp 
that  exact  dial  settings  are  an  absolute 
necessity  to  good  reception.  The  induc- 
tance coils  used  require  a  250  M.  M.  F. 
condenser  at  CI  and  C2: — if  any  other 
type  of  apparatus  than  that  shown  is 
used,  condensers  of  the  proper  size  to 
cover  the  broadcast  wave-band  should 
be  substituted. 

The  2,000  ohm  resistance  in  series 
with  the  B-battery  lead  on  the  radio 
frequency  amplifier  is  used  to  hold  this 
tube  below  the  point  of  oscillation.  If 
this  is  omitted,  it  becomes  necessary  to 
turn   the    R.    F.    rheostat   down    on    the 


lower  wavelengths.  This  is  less  efficient 
than  inserting  resistance  in  the  plate 
circuit.  The  writer  used  a  2,000  ohm 
potentiometer,  connecting  one  lead  to 
the  center  and  the  other  to  one  of  the 
outside  terminals;  either  terminal  gives 
the  same  result. 

After  the  set  is  wired,  the  results 
obtained  will  depend  a  great  deal  on 
the  adjustment  of  the  constants  of  the 
circuit.  The  use  of  an  air-core  trans- 
former, with  a 
variable  primary, 
permits  the  set  to 
be  adjusted  for 
varying  receiving 
conditions,  length 
of  antenna, 
and  proximity  to 
the  broadcasting 
stations.  As  the 
primary  is  raised 
the  set  becomes 
more  and  more 
selective,  and  at 
the  same  time  the 
volume  slowly 
drops  off.  By 
properly  setting 
this  primary,  the  best  balance  between 
selectivity  and  volume  may  be  ob- 
tained. The  primary  on  the  tuner  will 
generally  work  best  when  used  with  fairly 
loose  coupling  to  the  secondary.  This 
reduces  the  tendency  of  the  radio  fre- 
quency amplifier  to  oscillate  and  prevents 
the  detector  circuit  from  causing  it  to 
go  into  oscillation  when  the  tickler  coil 
brings  the  detector  up  to  the  point  of 
maximum  regeneration. 

The  100  M.  M.  F.  fixed  condenser 
across  the  audio  frequency  transformer 
may  be  omitted  in  a  great  many  cases, 
as  the  distributed  capacity  in  the  primary 
is  often  sufficient  to  permit  the  detector 
to  oscillate.  By  trying  various  values 
from  1000  M.  M.  F-  to  100  M.  M.  F., 
an  adjustment  may  be  obtained  such  that 
the  tickler  will  cause  the  detector  to 
oscillate  when  it  is  set  at  about  fifty  on 
the  dial.  This  is  about  the  right  setting 
for  easy  control. 


AMP    DET 
A  regenerative  receiver  witfrone  stage  of  R.  F.  amplification.    One  of  the  advantages  is  that  the  primary  tuning  can  be  adjusted  to 
the  signal  strength  received.     The  addition  of  a  stage  of  R.  F.  amplification  makes  this  set  more  selective,  more  sensitive  and  decreases 
annoying  radiation  to  an  unnoticeable  degree. 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


25 


SW/T/V/W* 


If  a  U.  V.-200  is  used  as  a  detector, 
a  six  ohm  rheostat  should  be  used  at  R2 
and  a  250  M.  M.  F.  grid  condenser  with 
a  two-megohm  grid  leak.  If  a  U.  V.-201- 
A  is  used  a  twenty-ohm  rheostat  should 
be  used  the  same  as  at  Ri  and  R3,  with 
a  three  or  four  megohm  grid  leak. 

The  constructor  should  have  abso- 
lutely no  difficulty  in  building  this  set, 
as  it  is  in  no  way  critical.  For  maximum 
results  only  the  best  type  of  low-loss 
transformer  and  tuner  may  be  used. 
The  minor  details  have  been  left  to  the 
judgment  of  the  constructor,  as  he  can 
hardly  go  wrong  if  he  employs  neat  and 
careful  workmanship  in  the  building  of 
his  set. 

Separating  KGO  and  WSAI 

TN  tests  a  set  of 
•*•  this  type  has 
brought  in  distant 
stations  with  good 
volume  and  excell- 
ent tone  quality. 
The  selectivity  is 
such  that  Stations 
KGO  at  312  meters 
could  be  perfectly 
separated  from 
WSAI  at  309  me- 
ters with  absolute- 
ly no  interference 
between  them.  By 
raising  the  adjust- 
able primary  on  T- 1, 
the  set  can  be  made 
so  sharp  that  tuning 
is  almost  impossible 
on   weak  signals. 

The  stations  are 
always  very  easy 
to  locate,  as  the 
detector  may  be 
made  to  oscillate 
and  the  stations 
found  by  the  beat 
note  or  whistle,  with 
which  you  are  all 
familiar.  A  selec- 
tive receiver  often 
gives  the  novice 
difficulty  in  tuning, 
as  the  stations  cover 
such  a  small  por- 
tion of  the  dial  that  locating  them 
is  to  him  somewhat  like  trying  to  find 
the  combination  of  a  safe  by  turning 
the  lock.  When  the  stations  are  easy 
to  find  he  complains  that  the  set  is  too 
broad.  When  it  is  sharp  he  cannot  tune 
them  in.    So  there  you  are! 

In  the  illustration  of  the  set  herewith, 
the  adjustable  primaries  are  set  down 
close  to  the  secondaries.  This  gives  the 
-  broadest  possible  tuning  and  is  the  best 
position  for  tuning  the  set  until  the 
-constructor  is  familiar  with  it.  After 
learning  to  tune  it  this  way,  he  should 
raise  the  primaries  until  the  desired 
degree  of  selectivity  is  obtained.  An- 
other good  characteristic  of  this  set  is 
that  the  stations  may  be  found  with  the 
detector  tube  oscillating  without  causing 
any  interference  to  your  neighbors,  as 
the  first  tube  reduces  the  amount  of 
radiation  to  a  negligible  quantity. 

Stations  will  always  come  in  at  the 
same  dial  setting,  providing'  the  batteries 


and  filament  rheostat  of  the  detector 
remain  the  same.  In  tuning,  the  detector 
rheostat  should  be  set  at  the  best  point 
and  not  disturbed  by  further  adjust- 
ments. 

For  anyone  wishing  to  increase  the 
sensitivity  and  selectivity  of  his  three 
tube  set,  or  to  construct  a  medium  sized 
receiver,  it  is  the  opinion  of  the  writer 
that  he  cannot  go  wrong  if  he  follows  a 
circuit  of  this  type. 

PARTS    REQUIRED 

Y-l    Air  core  transformer  (low-loss) 
T-2     Tuner  (low-loss) 
C-l  and  C-2     Vernier  Condensers 
T-s  and  T-4     Low    Ratio   Audio    trans- 
formers (2-1  or  3-1) 
R-l  and  R-3     20  Ohm  Rheostats 


GA/D 


'/TB/trr.  ~B~  B/tTT 

FUNDAMENTAL  RFGE/VER/IZ/VE 
RECE/VER   C/RCU/T 


Above  is  the  fundamental  regenerative  receiver  circuit  of  the  hookup  described 
in  this  article  by  Mr.  Piety.  On  the  opposite  page  is  shown  the  same  circuit  with 
one  stage  of  radio  frequency  amplification  added  to  the  original  hookup. 


R-2    6    Ohm    Rheostat    (20    Ohm    if    a 
U.  V.  201-A  is  used  as  a  detector) 

R-4     2,000  Ohm  Potentiometer 

R-5     1-2  Megohm  Grid  leak  (3  or  4  if  a 
201-A  is  used  as  a  detector) 

C-3     .0001  Fixed  Condenser 

C-4    .006  Fixed  Condenser 

C-S     .00025  Fixed  Condenser 

J-l     4  Prong  Jack 

J-2     2  Prong  Jack  with  Filament  Control 

7         Marked  binding  posts 

1         4J^  Volt  C  Battery 

1         Panel  size  7  "x24" 

1         Baseboard  size  7"x23° 

SW    Filament  Switch 

Screws,   wire,  solder,  dials  and  other 

small  accessories. 

IF  THE  builder  so  desires,  he  may 
install  a  jack  that  will  permit  him  to 
listen  on  the  detector  tube  only,  by  pur- 
chasing another  two  circuit  jack  and 
hooking  it  into  the  circuit  just  before 
the    first    audio   frequency   transformer. 


To  do  this  the  top  prong  is  soldered  on 
to  the  connection  that  comes  from  the 
rotor  of  the  "low  loss  tuner,"  the  second 
prong  is  connected  to  the  plate  side  of 
the  audio  frequency  transformer,  the 
third  prong  to  "B"  positive  side  of  the 
audio  frequency  transformer,  and  the 
bottom  prong  to  the  "B"  battery,  positive 
22  and  one-half  volts. 

The  fixed  condenser  across  the  pri- 
mary of  the  first  audio  frequency  trans- 
former is  connected  across  the  top  and 
bottom  prongs  of  the  jack. 

It  sometimes  is  advisable  in  a  circuit 
of  this  type  to  substitute  a  variable  grid 
leak  for  one  of  the  fixed  type.  The 
selection  of  this  article  will  be  left  to 
the  desire  of  the  builder,  but  he  is  cau- 
tioned against  mounting  it  in  such  a  posi- 
tion that  the  lead  to 
the  tube  socket  will 
be  exceptionally 
long.  There  are  at 
the  present  time 
several  variable  grid 
leaks  on  the  market 
with  long  bakelite 
(or  other  insulating 
material)  shaftsthat 
permit  the  resist- 
ance itself  to  be 
mounted  directly  to 
the  tube  socket,  but 
by  means  of  a  small 
knob  the  adjust- 
ment is  controlled 
from  the  panel.  If 
you  have  one  that 
is  not  of  the  type 
mentioned,  it  would 
be  best  to  sacrific 
the  convenience  of 
adjustment  and 
mount  it  inside  the 
cabinet,  right  on 
the  socket  itself. 

The  builder  is  re- 
minded that  it  is  not 
advisable  to  omit 
the  potentiometer 
when  building  the 
set.  Many  fans 
argue  that  the  in- 
serting of  a  poten- 
tiometer is  adding 
another  control  that  is  very  seldom  used 
and  does  not  increase  selectivity  to  any 
great  extent.  This  might  be  so  in  some 
circuits,  but  it  is  of  very  great  import- 
ance in  this  particular  one,  and  to  get 
maximum  results  it  should  be  included. 
In  closing  I  might  suggest  that  the 
builder  remember  that  this  is  a  very  selec- 
tive receiver.  And  as  such  he  might  have 
a  little  bit  of  trouble  regarding  the  re- 
ception of  really  distant  stations,  until 
he  has  properly  learned  to  handle  the 
set. 

If  he  will  but  remember  to  set  the 
primary  coil  close  to  the  secondary  until 
he  has  become  quite  proficient  in  hand- 
ling the  circuit,  then  he  will  be  sure  to  get 
the  results  for  which  we  all  so  eagerly  try. 
With  the  coil  in  this  position,  the  tun- 
ing will  be  quite  broad,  of  course,  but 
then  as  he  becomes  more  and  more  ex- 
perienced he  can  gradually  increase  the 
separation  between  the  primary  and  the 
secondary. 


26  RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


Discussing 
the  Pro  and  Con 
of  Regeneration 

for  The  Fan 


"7** 


TH  REE  radio  systems — regenera- 
tion, radio  frequency  and  the  super- 
hetrodyne — are  now  competing  for 
supremacy.. 

In  this  article,  the  concluding  one  of 
the  "Beginners'  Series"  which  began  in 
the  October  RADIO  AGE,  we  will  discuss 
regeneration  pro  and  con,  and  will  give  an 
example  of  regeneration  at  its  best  so  the 
beginner  who  has  reached  the  multi-tube 
stage  may  decide  whether  he  shall  choose 
that  type  of  reception. 

If  you  have  followed  this  series,  from 
the  crystal  hookup  to  the  one-tube  set, 
you  are  now  ready  for  the  next  step — 
three  tubes  or  more.  For  those  who  are 
still  uninitiated  into  the  first  principles 
of  radio,  the  writer  refers  them  to  the 
comprehensive,  explanatory  articles 
which  began  in  October  and  progressed 
by  easy  stages  to  the  present  status. 

Regeneration 

BRIEFLY,  the  "pro"  of  regeneration 
is  this.  Why  use  five  to  eight  tubes 
to  do  the  work  of  three?  The  answer 
is — to  get  greater  selectivity;  to  avoid 
radiation  and  to  secure  greater  amplifica- 
tion. 

A  single  circuit  regenerative  set,  like 
the  ultra-audion, 
becomes  a  broad- 
casting device 
whenever  the  feed- 
back is  increased 
until  the  set  whis- 
tles. That  whistle 
has  been  picked  up 
by  receivers  within 
ten  miles. 

Regenerative  sets 
were  "convicted"  of 
being  a  nuisance 
and  aroused  intense 
public  indignation 
when  they  seriously 
impaired  results 
during  Internation- 
nal  Radio  Week, 
late  in  1924.  The 
squeals  and  howls 
they  sent  forth 
made  it  impossible 
for  many  to  hear 
Europe  at  all. 
Many  who  tuned  in 
the  foreign  stations 
were  unable  to  dis- 
tinguish the  mes- 
sages because  o  f 
radiating  sets. 

Many  inventors, 
including  CarlPfan- 
stiehl,  have  conduc- 
ted laboratory  ex- 
periments in  radia- 


A  view  of  the  panel  of  Mr.  Eitel's  "DX  regenerator." 


Up  The  Ladder  with 

A  REAL  LOW  LOSS  REGENERATOR 


tion.  A  low  loss,  three-circuit  tuner  for  re- 
generative sets  has  been  designed  that 
practically  eliminates  howling.  This  is 
accomplished  by  the  use  of  an  aperiodic 
primary  or  .  untuned  antenna  circuit 
leading  to  the  ground.  This  circuit 
"accumulates"  all  signals  on  the  air. 
A  secondary  coil  for  the  grid  circuit  is 
tuned  for  the  wavelength  desired  and 
inductively  selects  the  signal  wanted. 

The  plate  circuit  makes  use  of  a  tickler 
coil — for  inductive  feed-back  or  regenera- 
tion. Therefore,  you  have  in  this  three 
circuit  device  a  non-radiating,  selective 
tuner.  How  about  more  amplification? 
If  you  are  content  to  use  your  outdoor 
aerial,  you  can  have  coast-to-coast  recep- 
tion with  this  tuner. 

HERE'S  THE  HOOKUP 


Here's  the  hooku 
Chicago  stations  to 
stations,  laud's. 


p.     There's  not  a  lot  to  it,  but  the  builder  tuned  through  powerful 
get  California  and  other  distant  stations.     And  on   some  faraway 
volume  was  secured  on  one  tube!     Try  it  and  be  convinced. 


J"  OW  loss  is  a  feature  of  the  accompany- 
-^  ing  set  described  in  this  article.  It  is  a 
well  known  fact  that  of  all  types  of  induct- 
ance, the  stagger  wound  coil  is  efficient. 
The  two  coils  shown  in  this  set  are 
lumped  inductances.  They  can  be 
coupled  to  within  a  thousandth  of  an 
inch  and  the  coupling  can  be  varied  at 
will  by  means  of  a  nut. 

Strictly  Low  Loss 

Another  feature  of  this  hookup  is  that 
the  magnetic  fields  are  flat  and  compact, 
thereby    preventing    inter-circuit    inter- 
ference, which  would  produce  howls  and 
distortion.     An  added  advantage  lies  in 
the  mechanism  for  varying  the  relation 
for  secondary  and  primary  coils.     This 
is  a  vernier  arrange- 
ment    that     passes 
the    coil    back    and 
forth     behind     the 
secondary        with 
gearing    that    per- 
mits the  finest  ad- 
justment. 

These  low  loss  re- 
ceivers have  been 
tested  all  over  the 
country,  including 
special  experiments 
in  Canada  last  Sum- 
mer. This  receiver 
is  an  all-around  dis- 
tance getter  and  in 
this  it  differs  from 
some  sets,  which, 
because  they  are 
not  thoroughly  low 
loss  receivers,  sus- 
tain a  special  handi- 
cap during  Summer 
due  to  static  condi- 
tions. 

Not  only  will  this 
set  get  the  distance, 
but  it  will  tune 
through  locals  with 
ease.  In  Chicago, 
while  the  powerful 
stations  are  pound- 
ing the  air.ithascut 
through  to  distant 
stations  at  will. 


RADIO  AGE  for  February,  1925 


A  rear  panel  view  of  the  set,  showing  simple  layout. 

the  Radio  Beginner 

FOR  DX  RECORDS,  BY  E.  H.  EITEL 


KGO,  at  Oakland,  Calif.,  was  heard  on 
three  consecutive  nights  on  one  tube  with 
the  head-set.  Hastings,  Nebr.,  Kansas 
City,  Elgin  and  Zion  were  heard  on  silent 
night  on  a  loud  speaker  with  one  tube, 
with  sufficient  volume  to  be  heard  plainly 
over  a  single  room.. 

This  set  also  logs  all  stations  within  a 
fraction  of  a  degree.  It  is  the  ideal 
regenerative  receiver  for  the  beginner. 

Some  Real  Results 

HERE  is  a  list  of  stations,  in  the  order 
given,  that  were  received  in  Chicago 
while  strong  locals  were  booming: 
(With    the    dial  readings.) 

WCK, 
St.  Louis,  21; 

WTAS, 
Elgin,    111.,    26; 

KFI, 
Los    Angeles,    60; 

WEBH, 
Chicago,  41; 

WBZ, 
Springfield,  37; 

WQJ, 
Chicago,  57  J^; 

KYW, 
Chicago,  75; 

WDAF, 
Kansas  City,  49  V2; 

KGW, 
Portland,  Ore.,  65. 
In  addition  to 
these  stations,  in 
between  WDAF 
and  KGW,  1  o  w 
power  stations  at 
Tallahoo,  Texas, 
New  Orleans,  Fort 
Smith,  Ark.,  Mon- 
roe, La.,  Madison, 
Kans.,  Bedford, 
Ind.,  Peoria,  111., 
and  Tulsa,  Okla., 
were  also  brought 
in  on  the  loud 
speaker. 

On  one  occasion 
this  receiver  was 
supposed  to  be 
operating  on  a 
long,    outside 


aerial.  This  antenna  system  consisted  of  a 
special,  four-cage,  seven-stranded  enam- 
eled wire  aerial,  100  feet  long,  with  a  sim- 
ilar cage  lead-in  of  thirty-five  feet.  The 
aerial  naturally  was  a  broad-tuning  one. 
This  meant  that  the  receiver,  to  give  good 
results,  must  naturally  be  a  sharp-tun- 
ing set. 

With  a  combination  of  this  type — long 
aerial  and  sharp  tuning — greater  distance 
and  greater  volume  without  sacrifice  of 
selectivity  can  be  obtained. 

Now,  the  queer  thing  about  this 
occasion  was  that  while  the  operator 
thought  he  was  using  this  long  outside 
aerial,  as  a  matter  of  fact  he  had  con- 


VACUUM  TUBE  DATA 


Typo 

FILAMENT 

PLATE 

fication 
Factor 

Mutual 

Con- 
ductance 

Make 

Voltage 

Current 

Battery 

1       Milli- 

Voltage  J    -  "meres 

Current 

Impedance 

C300 

C301 

C301A 

C299 

C12 

DV1 

DV2 

DV6A 

5.0 

5.0 

5.0 

3.0 

1.1 

3.0 

5.0 

4.0 
4.0-5.0 
4.0-6.0 

4.0 

2.5 

5.0 

5.0 

5.0 

3.0 

1.1 

1.1 

1.1 

2.5 

2.5 

2.5 

6.0 

1.00 
1.00 
0.25 
0.06 
0.25 
0.06 
0.25 
0.25 
0.6-0.7 

0.8 
0.25 
1.00 
1.00 
0.25 
0.06 
0.25 
0.25 
0.25 
1.10 
1.10 
1.10 
1.00 

Six  Volt  Storage 
Six  Volt  Storage 
Storage  or  Dry 
Three  Dry  CeU 
One  Dry  Cell 
Three  Dry  Cell 
Storage  or  Dry 
Storige  or  Dry 
Six  Volt  Storage 
Six  Volt  Storage 
Six  Volt  Storage 
Two  Dry  Cells .  . 
Six  Volt  Storage 
Six  Volt  Storage 
Storage  or  Dry 
Three  Dry  Cell 
One  Dry  CeU 
One  Dry  CeU 
One  Dry  CeU 
Storage 
Storage 
Storage 
Six  Volt  Storage 

15-24         .25   1.00 

9000 
14000-24000 
12000-16500 
16000-1S500 
17000-19000 

20000 
9000 

20000 

15000 

Cunningham 

Cunningham 

45-10J 
40-120 
40-80 
20-90 
20-80 
40-150 
20-100 
20-100 

1.00  5.00 
i.0j-7.5 
0.25-4.00 
0.25-^1.00 
0.25-4.00 

6.5 
8.0 
6.25 
6.5 
8.0 
6.5 

465 
485 
340 
340 
350 

1.00-5.00 

RAC3 

20-300 
20-150 
15-24 
45-100 
40-120 
40-80 
20-90 
20-90 
40-60 
20-45 
20-15 
20-45 
120 

30000 

25.0 

Myers 

UV200 

TJV201 

UV201A 

UV199 

WD12 

WD11 

215A 

203B 

VT1 

1 

216A 

0.25-1.00 
1.00-5.00 
1.00-7.50 
0.25-S.OO 
0.25-1.00 
0.25-4.00 
0.60-1.50 
0.50-2.00 
0.50-2.00 
0.50-2  00 
7-9 

9000 
14000-24000 
12000-16500 
16000-18500 
17000-19000 
17000-19000 

25000 
10000-20000 
10000-20000 
10000  20000 
5000-6000 

Radiotron 

Radiotron 

Radiotron 

Western  Electric . 
Western  Electric. 
Western  Electric. 
Western  Electric. 
Western  Electric. 

6.5 

S. 

6.25 
6.5 
6.5 
6  5 
6.5 
6.5  . 
6  5 
6.0 

465 
485 
340 
340 
340 
260 
650 
650 
650 
1000 

Make 

Type 

DETECTOR. 

AMPLIFIER. 

Rating 

Grid 
Condenser 

Grid 
Leak 

Audio 

Radio 

"C" 
Battery 

Base 

C300 

C301 

C301A 

C299 

C12 

DV1 

DV2 

DV6A 

Excellent 
Fan- 
Good 
Good 

Very  Good 
Fair 
Fair 
Jair 

Very  Good 
Good 
Good 
Good 
Escellent 
Fair 
Good 
Good 
Excellent 
Excellent 
Good 
Excellent 
Excellent 
Excellent      . 
Fair 

.00025-. 0005 

.0005 

.00025 

.00025 

.00025 

.00025 

.00025 

.00025 

.00025 

.00025 

.00025 

.00025 
.00025-. 0005 

.0005 

.00025 

.00025 

.00025 

.00025 

.00025 
.00025-.  0005 
.00025-. 0005 
.00025-.0005, 

.00025 

0.25-2.50 
2-5 
2-6 
2-6 
2-3 
2-3 

Fair 

Very  Good 
Excellent 
Fair  ' 
Good 
Fair 

Very  Good 
Good 
Good 
Good 
Good 
Good 
Fair 

VeT  Good 
Escellent 
Fan- 
Good 
Good 
Fair 
Good 
Good 
Good  . 
Escellent 

Poor 
Good 
Fair 
Good 
Good 
Fan- 
Fair 
Good 
Good 

Very  Good 
Good 
Good 
Poor 
Good 
Fan- 
Good 
Good 
Good 
Fair 
Fair 
Fair 
Fair 
Good 

1.5-4.5 
1.0-6.0 
1.0-4.5 
1.5-4.5 

2.0-4.0 

RAC3 

1-5 
1-5 

0.25-2.5 

2-5 

2-6 

2-6 

2-3 

2-3. 

2-5 
Q.oV-3.0 
0.5-3.0 

1-5 

TTV200 

UV201 

UV201A 

TJV199 

WD  12 

WD11 

215A 

203B 

VTl 

3 

216A 

1.5-4.5 

1.0-6.0 

1.0-4.5 

1.5-4.5 

1.5-4.5 

1.0 

1.5 

1.5 

1.5 

9. 

Western  Electric 

Western  Electric 

Western  Electric 

Special 

Standard 

Standard 

Standard 

Standard 

The  Magazine  of  the  Hour  27 

Why  Use 

a  Five  or  Eight 

Tube  Set  When 

3  Will  Do? 


nected  the  set  to  a  second  aerial  which 
was  an  inside  one  and  only  fifty  feet  in 
length.  It  was  fully  half  an  hour  before 
the  discovery  was  made  that  the  short, 
inside  aerial  was  in  use.  Already  he  had 
brought  in  the  St.  Louis,  Los  Angeles 
and  Springfield  stations  on  the  loud- 
speaker. 

The  set  will  be  easy  to  construct 
through  referring  to  the  diagram  and 
pictures  accompanying  this  article. 
Following  are  the   parts  needed: 

1.  One  three-circuit,  low  loss  tuner. 

2.  One  single  hole  mounting  rheostat. 
If  you  use  UV  200  or  C300  detector  tube, 
make  this  a  vernier  rheostat. 

3.  One  .00035  variable  condenser, 
low  loss  type. 

4.  One  fixed  condenser,  .00025  mfd., 
combined  with  grid  leak  of  a  resistance 
in  accord  with  tube  used  (See  table  for 
tubes  with  this  article).  For  simplicity, 
UV201A  or  C301A  tubes  are  recom- 
mended throughout;  variable  grid  leak, 
0  to  5  megohms,  may  be  used. 

5.  One  shock-proof  socket. 

6.  Audio  transformers. 

7.  UV201A  or 
C301A  tubes  with 
socket  for  same. 

8.  One  panel, 
(6"xl8",  or  8"  by 
15".) 

9  Jacks,  bind- 
ing posts,   etc. 

10.  Single  Cir- 
cuit Jack. 

To  construct 
the  set,  mount  the 
parts  on  the  pane! 
in  the  arrange- 
ment as  shown  in 
the  accompanying 
photographs,  and 
hook  up  with  flex- 
ible copper  wire, 
making  connec- 
tions direct  from 
terminal  to  termi- 
nal, which  is  the 
only  true  low-loss 
method.  Be  sure, 
of  course,  to  solder 
all  connections 
firmly. 

Adding  amplifi- 
cation is  a  com- 
paratively simple 
matter.  The  most 
essential  feature  is 
to  use  low  ratio 
transformers  if  you 
wish  good  music. 
The  pictorial  and 
(Turn 'to  page  77) 


28 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


Converting  the  SINGLE  Circuit 

By  C.  HAROLD  DILLON 

How  the 

Single  Circuit 

May  be  Changed 

to  An  Efficient 

Reflex  Set 

single  circuit  set.  Considering  these 
devices  from  an  economic  standpoint, 
they  have  proven  to  be  very  undesirable. 

In  the  search  for  something  that  would 
give  really  good  results,  it  was  found  that 
by  making  use  of  the  reflex  principle, 
the  single  circuit  receiver  could  be  modi- 
fied to  quite  an  advantage.  Indeed,  I 
think  I  can  be  safe  in  saying  that  in 
making  this  change  you  will  find  it  to  be 
a  geniune  improvement. 

To  secure  the  satisfactory  results 
obtained  from  a  reflex  circuit,  it  is  not 
necessary  to  throw  away  your  present 
single  circuit  set.  By  simply  changing  a 
few  connections  on  the  receiver  and  in- 
stalling a  few  new  pieces  of  apparatus, 
your  once  despised  "single"  becomes  an 
ultra-modern  set  that  will  prove  a  revela- 
tion as  far  as  signal  quality  and  strength 
are  concerned.  Figures  1  and  2  will  en- 
able you  to  get  a  detailed  photographic 
view  of  the  apparatus  required,  and  you 
will  see  upon  closer  inspection  that  the 
wiring  is  not  at  all  difficult.    I  might  state 

here  that  this  unit  can  be  used  on  any  -,— ,,-*,„  ,,  ,        c        i  •       »l'      _^-  i 

.     ,  ,,  ,   .,  L'UR  the  sake  ot  making  this  article  as 

single  circuit   receiver  regardless  of   the  p      ,  ...       T    " ...     ,  ., 

°        ,  .       .  -*-     clear  as  possible,    I   will  choose  the 


Fig.  1.  A  front  view  of  the  "converter." 
The  dial  is  used  for  varying  the  capacity  of 
the  condenser ,  permitting  the  reception  oftlie 
lower  and  higher  wavelengths. 

DURING  the  past  year  much  has 
I  been  said  condemning  the  single 
circuit  regenerative  receiver.  In 
fact,  it  seems  as  though  everyone  has 
deserted  this  old  time  favorite,  which  in 
a  short  space  of  time  has  fallen  into 
almost  complete  disuse. 

Such  is  the  way  of  the  world.  Looked 
upon  at  one  time  as  one  of  the  greatest 
wonders  of  modern  science,  the  single 
circuit  regenerator  is  today  cast  into 
the  scrap  heap  of  the  despised  and  detest- 
ed things  of  this  earth.  Regardless  of  the 
faults  of  the  single  circuit  tuner,  and  the 
sincere  desire  to  remedy  them,  the  propa- 
ganda against  them  has  been  more  of  a 
destructive  nature.  Very  few  persons 
have  attempted  to  devise  methods  of 
curbing  its  one  fault,  that  of  radiation. 
But  there  are  many  of  us  who  invested 
our  entire  radio  pocket-book  in  single 
circuit  receivers  and  who  must  necessarily 
pause  and  consider  before  scrapping  the 
old  "stand-by"  and  purchasing  the  new- 
er types. 

To  Eliminate 
Radiation 

FROM  time  to 
time  various 
schemes  have  been 
forwarded  that 
would  permit  the 
operation  of  these 
sets  and  at  the 
same  time  eliminate 
the  undesirable  ra- 
diation. These 
schemes  have  been 
mostly  in  the  form 
of  radio  frequency 
amplifier  units,  to 
be  added  before  the 
detector  tube  of  the 


Fig.  Z.  A  side-view  of  the  single-circuit 
converter,  showing  the  R.  F.  transformer, 
the  condenser,  the  A.  F.  transformer  and 
the  crystal  detector. 

One    variable    condenser    cap., 

.  0025 3.00 

One  piece  cardboard  tubing. .20 

1-6  pound  No.  22  DCC  wire .30 

One  panel,  about  6"x6"_ _  .40 

Dial .60 

Incidentals : .50 

Total $10.00 

Is  Your  Set  Like  These? 


slight  mechanical  changes  the  circuit 
may  employ.  The  parts  necessary  to 
reflex  a  single  circuit  tuner  can  usually 
be  found  in  the  experimenter's  laboratory 
or  can  be  purchased  from  any  first  class 
radio  shop  for  a  nominal  sum. 

Below   is   a   bill   of   the    materials   re- 
quired. 

The  Bill  of  Materials. 

One  crystal  detector,  fixed SI. 00 

One  audio  transformer _ 4.00 


Figures  3  and  4.     Fig.  3  is  the  single  circuit  receiver  as  most  generally  known, 
while  Fig-  4  shows  the  same  circuit  converted  into  a  single-tube  reflex. 


type  of  single  circuit  tuner  in  most 
common  use  today.  If  you  will  compare 
your  present  set  with  figure  3,  you  will 
find  that  Al  and  A2  are  primary  and 
secondary  windings  of  your  vario-coupler. 
In  some  sets  that  have  been  sold,  you  will 
find  that  a  variometer  has  been  substi- 
tuted for  the  coupler.  In  that  case, 
Al  is  the  stator  and  A2  the  rotor.  The 
condenser  in  the  ground  circuit  is 
usually  one  having  a  capacity  of  .0005 
M  F  (23  plate). 
Figure  4  is  the  com- 
pleted wiring  dia- 
gram of  the  rewired 
single  circuit- receiv- 
er, showing  the 
added  apparatus  to 
the  right,  indicated 
by  the  dotted  lines. 
You  will  notice  that 
the  only  wires  that 
have  not  been 
changed  are  the  lead 
from  the  antenna 
and  the  filament. 

Whether  to  mount 

the  apparatus  on  a 

small  panel  or  install 

it  right  in  the   set 

{Turn  to  page  64) 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


29 


SIT  The  Hidden  Voice 


By  FRANK  HONEYWELL 

Final  Installment  of  The 
Adventures  of  a  Kidnapped 
Baby  Who  Was 
|j^    Rescued  by  a  Bit 
of  Radio 
Ingenuity 


■c 


Chapter  II 
"The  Baby's  Stomach.' 

(Continued  from  January  Radio  Age) 

"Drat  the  kid,"  muttered  the  woman. 
"Who  ever  heard  of  such  a  thing?  How 
did  he  ever  learn  to  talk  like  that?  Talks 
like  a  man.  I  must  get  rid  of  him  mighty 
quick,  or  I'll  drop.  Ah,  there's  the  park. 
I'll  get  rid  of  him  there." 

A  block  further  she  pushed  the  carriage 
into  one  of  the  city's  big  parks,  plenti- 
fully supplied  with  trees,  bushes,  duck 
ponds,  golf  links,  and  baseball  diamond. 
Into  some  bushes  near  the  ball  grounds 
she  pushed  the  carriage  and  there  aban- 
doned it  with  a  great  sigh  of  relief. 

What's  Wrong  Here? 

A  FEW  moments  later  a  ball  struck 
by  one  of  a  group  of  boys  hit  the 
ground  a  few  yards  away  and  rolled  into 
the  bushes  near  the  carriage.  A  fielder, 
chasing  the  ball,  heard  a  cry  of  "Help, 
help,  murder!"  and  raced  back  in  affright. 

"Oh,  kids,"  he  yelled,  with  the  pallor 
of  fear  on  his  face;  "somebody's  being 
killed  in  those  bushes." 

In  a  few  moments  all  the  other  ball 
players  were  gathered  around  him, 
listening  to  his  story.  Some  of  them 
scoffed  at  it;  others  were  disposed  to 
take  it  seriously.  At  length  they  agreed 
to  approach  the  bushes  in  a  body  and 
make  an  investigation. 

They  were  almost  at  the  edge  of  the 
thicket  before  they  could  distinguish  a 
sound.  Then  a  faint,  "Help,  help!" 
reached  the  ears  of  all. 

"There's  sure  somethin'  going  on  in 
there,"  one  of  the  older  boys  vouched. 
"Now  the  question  is,  who's  going  to 
go  in  and  rescue  him?" 

"Not  I,"  declared  one. 

"Nor  I,"  chimed  another. 

"Let's  holler  to  the  guy  'at's  killin' 
him  and  tell  him  we'll  come  in  and  beat 
him  up  with  clubs  if  he  don't  stop," 
proposed  another  ball-player  scarce  above 
a  whisper.    He  held  his  club  dangerously. 

"I  see  something  in  there,"  announced 
a  youth  who  had  not  spoken  thus  far. 
"It  looks  like  a  big  basket.  I  can  almost 
reach  it  with  my  hand.     No,  it's  a  baby 


mm 

it  Qgr< 


buggy.  Here,  Ted,  take  hold  of  my 
hand  and  give  me  a  jerk  back  if  I  get 
in  trouble.  I'm  goin'  to  see  if  I  can't 
drag  it  out." 

Ted  seized  his  hand,  and  he  reached 
into  the  bushes  with  the  other,  and 
presently,  sure  enough,  out  came  a  very 
respectable  looking  baby  •arriage,  with 
a  real  live  infant  less  than  a  year  old 
in  it,  screaming  in  a  half-choked  voice, 
it  seemed: 

"Help!  help!  murder!  I'm  kidnapped. 
Police,    police,    arrest    my    kidnapper." 

"Jimminy  crickets!" 

"Gosh  all  fishhooks!" 

"Gee-mently!" 

That's  about  all  the  flabbergasted  boys 
could  say  as  they  gawked  at  the  infant, 
who  bit  viciously  at  his  zwieback  and 
yelled  in  sepulchral  tones: 

"Help,  help!  Rescue  me.  Don't  let 
them  murder  me." 

"What's  the  matter,  boys?" 

It  was  Mr.  Benson,  pastor  of  a  church 
nearby.  He  was  taking  a  walk  through 
the  park  and  seeing  the  strangely-acting 
group  of  young  ball  players,  he  advanced 
to  investigate. 

"Matter!"  exclaimed  one  of  the  young- 
sters. "Just  listen  here.  Did  you  ever 
hear  anything  like  that?" 

"A  baby  not  more  'n  a  year  old,  talkin' 
like  a  grown-up,"  put  in  another  of  the 
flabbergasted  group. 

"Let  me  see,"  proposed  the  minister, 
stepping  beside  the  carriage.  "What's 
the  matter,  baby?"  he  asked  in  a  tone  of 
sympathy  that  expects  no  answer. 
"Whose  little  child  are  you?" 

"Murder!"  came  a  responsive  screech 
from  the  pillows  and  quilts.  "Help, 
help!  Take  me  back  to  mamma.  Mur- 
der!" 

"Astonishing!"  exclaimed  the  minister, 
throwing  up  his  hands.  "Sounds  like 
ventriloquism,  as  if  the  voice  comes  from, 
its  stomach.     Remarkable,  very  remark- 


"Who's  little  child  are 
you?"  the  minister 
asked  the  baby.  "Mur- 
der!" was  the  response. 
"Help!  Take  me  back 
to  my  mammal  Mur- 
derl" 


able.  This  must  be  investigated.  I'm 
going  to  wheel  this  carriage  home  and 
call  up  the  police." 

Followed  by  a  score  of  ball  players, 
who  by  this  time  had  lost  all  interest  in 
their  game,  the  Rev.  Mr.  Benson  pushed 
the  carriage  across  the  neatly  mowed 
lawn  toward  his  home.  As  he  was 
crossing  a  driveway,  a  motorcycle  police- 
man raced  up  and  blocked  further  ad- 
vance. 

"Whose  baby  is  that?"  demanded  the 
"cop,"  who  did  not  know  the  minister. 

"I    don't    know,"    the    latter    replied. 

"Help,  help!'  came  a  cry  from  the 
carriage.  "I'm  being  kidnapped.  Help, 
help!    Police!" 

Stumping  the  Law 

THE  policeman  nearly  lost  his  grip 
on  the  motorcycle. 

"What  in  blazes  does  this  mean?"  he 
demanded. 

"Blessed  if  I  know,"  answered  Mr. 
Benson.  "These  boys  just  found  this 
baby  in  the  bushes  over  there,  and  I'm 
taking  it  home  with  me  to  see  if  I  can't 
find  out  whom  it  belongs  to." 

"I  think  I  know  whose  baby  it  is," 
said  the  officer.  "We  had  a  call  that  a 
baby  was  stolen  from  Mrs.  Stansbury 
on  Marcey  Avenue.  Come  along  with 
me,  and  we'll  find  out  if  it  isn't  hers." 

The  cries  for  help  continued  at  short 
intervals  all  the  way  to  the  Kinney 
home.  The  policeman  drove  his  motor- 
cycle slowly,  Mr.  Benson  pushed  the 
carriage  swiftly,  and  the  youthful  ball 
players  trailed  along  behind,  eager  for  a 
solution  of  the  mystery.  As  they  ap- 
proached the  house,  out  flew  the  hysteri- 
cally joyful  mother,  who  seized  little 
Edward  in  her  arms  just  in  time  to  re- 
ceive a  string  of  "Help,  help,  murders" 
in  her  ears.  (Turn  to  page  70) 


30 


RADIO  AGE  for  February,  1925 


What  the  Broadcasters  are  Doing 


What  the     ps 
Broadcasters 

D 


KOA  on 


\  NOTHER  national  radio  voice,  KOA, 
^*-  the  Rocky  Mountain  broadcasting 
station  of  the  General  Electric  company 
at  Denver,  Colo.,  is  now  on  the  air. 
The  wavelength  for  the  present  will  be 
323  meters  and  the  power  rating  1,500 
watts. 

Opening  of  KOA  marked  the  com- 
pletion of  the  General  Electric  chain 
of  three  broadcasting  stations  across  the 
United  States,  WGY  at  Schenectady, 
N.  Y.,  and  KGO  at  Oakland,  Calif. 

KOA,  it  was  pointed  out,  is  the  half 
way  point  between  the  Mississippi  and 
the  Pacific  and  Canada  and  Mexico, 
and  will  be  heard  by  millions  from  one 
end  of  the  American  continent  to  the 
other.  Already  hundreds  of  letters, 
telegrams  and  long  distance  telephone 
calls  have  been  received  at  the  station 
in  response  to  initial  programs.  _ 

A  public  reception  at  the  station  took 
place  December  18,  and  was  attended 
by  a  number  of  prominent  state  and  city 
officials.  Invitations  were  extended  to 
numerous  radio  officials  in  the  East  and 
on  the  Pacific  coast. 

"From  foundation  to  roof,  this  station 
has  been  designed  and  built  for  the  sole 
purpose  of  radio  broadcasting,"  declared 
Martin  P.  Rice,  director  of  radio  broad- 
casting of  the  General  Electric  organiza- 
tion, who  supervised  arrange  ments  for 
the  opening. 

"It  embodies  all  the  technical  and 
mechanical  improvement  suggested  by 
the  experience  of  our  other  broadcasting 
stations. 

"While  KOA  will  be  operated  at  1,500 
watts,  the  equipment  has  additional 
capacity  available  for  testing.  As  a  re- 
sult, tubes  and  rectifiers  will  not  be  sub- 
ject to  over-loads  and  transmission  will 
be  marked  by  greater  reliability  and  ex- 
cellence of  quality.  Additional  power  is 
afforded  also,  for  experimental  purposes. 

"Use  of  broadcasting  pick-up  circuits 
will  permit  public  events,  addresses, 
concerts  and  the  services  of  many 
churches  to  be  placed  on  the  air.  The 
station  is  surrounded  by  a  rich  field  of 
talent  from  which  to  select  music,  enter- 
tainment and  educational  features  in 
addition  to  the  KOA  staff  artists." 

Cost  of  construction  approximated 
$175,000  and  it  was  estimated  the  annual 
cost  of  maintenance  will  reach  $  100,000. 
The  KOA  staff,  when  completely  organ- 
ized, will  number  twenty  members, 
including  a  resident  engineer  in  charge 
of  technical  operations,  program  mana- 
ger, operators  and  announcers  and  mem- 


Above  is  F.  A.  Hill,  one  of  the  experts  on  the 
engineering  staff  of  KYW,  Chicago,  whose  article 
on  "The  Outside  Man,"  to  be  found  at  the  column 
to  the  right,  will  prove  interesting  to  the  fans 
who  often  wonder  what  goes  on  behind  the  scenes 
when  an  event  of  importance  is  broadcast.  Mr. 
Hill  tells  all  about  it. 


bers  of  the  news  bureau  and  the  office 
personnel. 

KOA's  antenna  system,  120  feet  long, 
is  150  feet  above  the  ground  and  is 
supported  by  two  triangular  steel  towers, 
260  feet  apart.  Directly  beneath  is 
the  two-story  studio  building  in  which  is 
housed  a  large  reception  room,  waiting 
room  for  artists,  general  offices  and  a 
concert  studio  and  auxiliary  or  speakers' 
studio.  In  the  rear  and  adjoining  is  a  one- 
story  power-house  and  generator  room. 

For  the  present,  programs  are  broad- 
cast three  nights  a  week,  the  dates  to 
be  announced  later,  in  addition  to  Sunday- 
features.  Harry  D.  Randall,  Rocky 
Mountain  district  manager  of  the  General 
Electric  company,  has  local  supervision 
of  the  station. 


"Brunswick  Hour"  New 
Radio  Feature 

HPHE  third  National  Relay  program — 
-*-  the  "Brunswick  Hour  of  Music" — 
went  on  the  ether  on  Tuesday,  Decem- 
ber 23rd,  at  9:00  p.  m.  Central  Standard 
Time. 

This  program  is  broadcast  by  WJZ, 
New  York,  picked  up  and  re-broadcast 
by  KYW,  Chicago,  KDKA,  WGY, 
WRC,  KFKX  and  KGO.  The  artists 
appearing  on  these  programs  are  of 
world-wide  fame  and  the  purpose  of  the 
National  Relay  program  is  to  give  the 
radio  public  of  the  country  an  opportunity 
to  listen  in  on  a  rare  one  hour's  enter- 
tainment. 

The  first  program,  on  Tuesday,  Dec. 
9th,  included  selections  by  the  Cleveland 
Symphony  Orchestra,  under  the  direc- 
tion of  Nikolai  Sokoloff,  a  musician  of 
international  reputation.  Mme.  Elly 
Ney,  Miss  Florence  Easton,  Mario 
Chamlee  and  others,  w~ho  are  leaders  in 
the  musical  world,  also  appeared  on  the 
initial  program. 

On  Tuesday  evening,  Dec.  16th,  at 
9  o'clock,  the  second  national  relay 
program  was  given.  Among  those  who 
appeared  on  the  program  were  Miss 
Margaret  Young,  Miss  Marion  Harris 
and  Ray  Miller  and  his  orchestra. 

The  program  for  Tuesday,  December 
23rd,  brought  with  it  such  celebrities 
as  Miss  Claire  Dux,  John  Charles 
Thomas,  Leopold  Godosky,  pianist,  and 
the  Elshuco  Trio. 

"The  Brunswick  Hour  of  Music"  is 
a  new  departure  in  radio  activity,  in 
that  several  stations  co-operate  in  its 
broadcasting.  With  the  rapidly  growing 
improvements  in  the  re-broadcasting 
art,  this  promises  to  become  a  popular 
feature,  the  intention  being  to  promote  a 
greater  appreciation  of  good  music. 


Gladys  Frazin,  of  the  "White  Cargo"  company 
in  Chicago,  established  a  radio  reputation  as  an 
actress  when  the  play,  in  which  she  is  the  star, 
was  broadcast  from  KYW.  Microphones  were 
placed  at  advantageous  points  in  the  Cort  Theater, 
Chicago,  and  the  audience  was  told  that  the  play 
was  to  be  sent  over  the  ether  to  untold  thousands 
of  listeners.  Then  the  play  began,  and  hundreds 
of  listeners,  after  hearing  the  melodramatic  mom- 
ents, went  to  see  "White  Cargo"  afterward. 
Experts  reported  the  play  was  unusually  suited  to 
radio  broadcasting. 


"The  Outside  Man" 

By  F.  A.  Hill,   (Engineering  Staff, 
Westinghouse  KYW) 

PARADOXICAL  as  the  above  caption 
may  sound,  the  outside  man  is  on  the 
inside  of  everything,  at  least  as  far  as 
Westinghouse  and  radio  broadcasting 
are  concerned  in  Chicago.  For  the  out- 
side man  is  the  one  that  does  the  physical 
and  electrical  work  to  make  a  success 
of  the  many  pickup  jobs  which  KYW 
has  taken  on  its  shoulders  since  its 
inception. 

These  outside  jobs  are  first  spotted 
by  the  publicity  department  and  then 
turned  over  to  operations  for  fulfillment. 
And  that  is  where  the  work  is  crowned 
either  with  grief  or  success.  It  is  one 
(Turn  to  page  60) 


RADIO  AGE  for  February',  1925 


Wlmt  the  Broadcasters  are  Doing  31 


Radio's  Effect  on  the 
Popular  Song 

By  TED  FIORITO 


Ted  Fiorito  and  Dan  Russo, 
co-conductors  of  the  Oriole  Or- 
chestra from  Station  WEBH.  At 
the  right  is  the  entire  orchestra, 
which  has  gained  fame  through 
broadcasting  for  the  radio. 


J 'ED  FIORITO,  the  author  of  this 
article,  is  one  of  the  best  known  and 
most  accomplished  pianists  in  America. 
He  is  one  of  the  co-conductors  of  the 
famous  Oriole  Orchestra,  which  appears 
regidarly  over  Radio  Station  WEB  II, 
Chicago.  He  is  the  author  of  such  famous 
songs  as  "  No,  No,  Nora,"  "Charley,  My 
Boy,"  "When  Lights  are  Low,"  "Dreamer 
of  Dreams,"  "Eliza,"  and  many  others. 
Herewith  he  tells  how  radio,  in  his  estima- 
tion, has  affected  the  status  of  music  in 
A  merica. 


I  HAVE  been  asked  whether  I  believe 
radio  is  a  good  vehicle  for  the  promo- 
tion of  popular  songs,  and  being  both 
a  composer  and  a  constant  radio  per- 
former, I  am  placed  in  a  rather  peculiar 
position. 

I  have  always  considered  the  radio  a 
happy  invention  that  makes  for  more 
happiness  in  the  home,  and  accordingly 
I  have  been  most  enthusiastic  with  regard 
to  broadcasting  songs  through  the  air. 
Naturally,  I  also  considered  it  a  good 
medium  for  the  popularization  and  ad- 
vertising of  songs,  and  so  I  felt  that 
every  time  the  Oriole  Orchestra  broad- 
cast a  number,  it  was  to  a  certain  ex- 
tent helping  the  publisher  of  that  number 
to  achieve  widespread  publicity  for  his 
piece. 

And  everyone  else,  coming  to  the  same 
conclusion,  started  a  great  campaign 
to  popularize  his  own  numbers. 

And  Radio  Fans  "Took"  It 

WHAT  was  the  result  of  this?  The 
public  was  treated  to  an  army  of 
songs,  some  of  which  were  good,  some 
indifferent  and  some  pretty  poor — and 
you  can  easily  see  how  the  good  selec- 
tions could  be  lost  in  the  shuffle,  and 
that  the  radio  loving  public  were  given 
rather  a  hard  dose  to  swallow. 

Now  suppose  a  number  had  come  quite 


in  favor  and  was  in  great  demand. 
Stations  all  over  the  country  broadcast 
it  continually  in  answer  to  the  requests  of 
the  people,  and  radio  "fans"  heard  it  so 
often  that  the  tune  and  words  were  soon 
learned,  and  there  was  no  necessity  to 
buy  the  sheet  music  or  records.  The 
result  of  this  was  that  the  publishers 
and  writers  who  had  gone  to  great  pains 
and  expense  lost  out  and  were  not  given 
the  fruits  of  their  labor.  In  fact,  some 
songs  that  would  have  naturally  achieved 
a  million  copy  sale  made  just  a  little 
money  for  the  interested  parties  because 
they  were  "broadcast  to  death." 

These  arguments  might  tend  to  make 
you  believe  that  I  am  a  firm  opponent 
of  radio,  especially  with  regard  to  its 
influence  on  the  popular  song;  but  still 
a  consideration  of  other  points  that  I 
will  bring  to  your  attention  heips  combat 
the  foregoing  arguments. 

There  are  a  number  of  people  who 
never  appreciated  popular  songs  and 
would  never  have  enjoyed  this  particular 
kind  of  pleasure  were  it  not  for  the  radio. 
Constant  listening  in  has  trained  them  to 
the  value  of  ballad,  fox  trot,  and  waltz 
pieces  as  an  important  part  of  our  life 
today,  for  they  certainly  are  factors  that 
help  to  dispel  gloom  and  bring  happiness 
by  creating  a  train  of  thought  that  has 
no  room  for  trouble. 

Radio  Helps  Many 

TAKING  the  financial  view  of  the 
matter,  there  are  numbers  which  are 
really  excellent  ones  and  which  would 
never  enjoy  success  were  it  not  for  the 
impetus  given  them  by  the  radio. 

My  conclusion,  therefore,  is  a  sort  of 
fifty-fifty     proposition. 

Radio  is  a  good  medium  for  acquaint- 
ing the  public  with  popular  songs,  pro- 
vided the  station  directors  specialize  on 
the  good  ones  as  a  general  rule. 

But   radio,   on   the   whole,   has  a   bad 


financial  effect  on  the  publishers  and 
writers  who  do  not  receive  all  that  is 
coming  to  them.  Legislation  will  prob- 
ably soon  remedy  this  evil,  however, 
and  give  these  individuals  their  just 
profits. 

Some  Xmas  Greetings 

A  NOVEL  plan  that  other  leaders  of 
orchestras  broadcasting  melodies 
through  the  air  can  do  well  to  emulate 
was  inaugurated  by  the  Oriole  Orchestra 
over  WEBH  Christmas  Eve.  Realizing 
that  thousands  of  "listeners-in"  who 
heard  their  tunes  nightly  have  often 
had  a  desire  to  become  acquainted  with 
the  personnel  of  the  station  and  the 
orchestra,  they  did  their  bit  by  personally 
broadcasting  Christmas  greetings  for 
the  orchestra,  and  by  giving  the  people 
a  brief  talk  regarding  the  work  they  do 
and  what  they  have  accomplished. 

Radio  "fans"  all  over  the  country 
were  informed  of  this  event  and  "tuned 
in"  at  the  stipulated  time  when  Russo 
and  Fiorito  gave  their  talk.  As  a  prelude, 
a  series  of  popular  numbers  written  by 
members  of  the  orchestra  was  given,  and 
this  included  "Toot,  Toot,  Tootsie," 
by  Russo,  "Dreamy  Melody,"  by  Naset, 
and  "No,  No,  Nora,"  "Charley  My 
Boy,"  and  "Dreamer  of  Dreams,"  by 
Fiorito.  The  composers  themselves 
"soloed"  the  songs,  so  those  fortunate 
enough  to  be  listening  in  were  given  a 
treat  indeed. 

Not  only  do  these  famous  syncopaters 
broadcast  popular  songs  in  a  manner 
most  inspiring  to  dance  lovers,  but  they 
are  proficient  in  concert  numbers  as  well, 
and  constantly  regale  the  public  with 
classical  treats. 

No  other  orchestra  has  done  so  much 
to  raise  the  standard  of  musicianship  in 
dance    aggregations    as    has   this   group. 

WEBH  is  located  on  the  Edgewater 
Beach  Hotel. 


32 


RADIO  AGE  for  February,  1925 


What  the  Broadcasters  are  Doing 


Still  Laughing  In  His  Dreams 


CJack  Nelson,  a  Pioneer 

Radio  Star,  Spurts 

Ahead  in  Our 

Contest 

TO  Jack  Nelson,  Director  of  Station 
WJJD,  goes  the  credit  for  having 
received  the  greatest  number  of 
Popularity  Ballots  during  the  period 
from  November  16  to  December  15. 

Jack  Nelson  is  a  real  Chicago  product, 
having  been  born,  raised  and  educated 
there.  At  the  age  of  seven  his  mother 
was  able  to  keep  him  at  the  piano  for 
part  of  an  hour  each  day  in  spite  of  the, 
"  Yoo  Hoo,  Skinnay's,  "which  penetrated 
the  quiet  of  the  parlor.  The  lure  of  the 
baseball,  bicycle  and  the  skates  was  much 
greater  than  that  of  the  ivories,  but  in 
some  way  or  other  he  managed  to  con- 
tinue his  study  of  classical  music. 

His  father  died  when  he  was  ten  years 
old  and  later,  when  in  high  school, 
Jack  began  to  forsake  the  realms  of 
classical  music,  as  the  playing  of  dance 
music  began  to  be  of  assistance  financially. 

While  a  junior  at  Lane  Tech  High 
School,  he  composed  the  words  and  music 
for  "Go,  Lane,  Go"  which  is  the  official 
song  of  that  High  School  and  is  still  sung 
with  great  enthusiasm  by  the  3,500  boys 
there.  He  was  awarded  a  scholarship  at 
Northwestern  University  for  excellence 
in  studies  at  Lane  and  surprised  the  Cam- 
pus when,  as  a  freshman,  most  of  the 
songs  for  the  annual  Musical  Comedy 
were  written  by  him. 

Before  he  left  the  University,  Jack  had 
written  or  collaborated  upon  four  annual 
musical  shows  given  by  the  Men's 
Dramatic  Organization,  Hermit  and 
Crow,  one  of  which  was  so  popular  it  is 
being  reproduced  this  year.  In  his  Senior 
year  at  Northwestern  University,  he  was 
awarded  a  diamond  and  platinum  Sigma 
Nu  badge  for  writing  the  official  national 
song  of  that  fraternity,  "The  White 
Star  of  Sigma  Nu."  In  his  Senior  year, 
also,  he  was  Director  of  the  Glee  Club 
which  was  sent  by  the  United  States 
Government  to  entertain  the  residents  of 
the  Canal  Zone,  being  royally  entertained 
by  officials  of  the  Haitian  Government, 
the  Panama  Government  and  the  Ameri- 
cans in  Panama. 

On  The  Upward  Climb 

A  FTER  he  left   College,   Jack   was  a 
-^-salesman  for  a  jewelry  house  and  later 


By  Harry  Aldyne 


POPULARITY  CONTEST  COUPON 

Harry  Aldyne,  Contest  Editor, 

RADIO  AGE,  500  N.  Dearborn  St.,  Chicago. 

I  wish  to  cast  my  vote  for: 


Name  of  favorite.. 

Classification. 

Station 

Name  [optional] — 


..Date  Heard.. 


Address  [optional].. 


(Photo  by  Drake  Studio) 

Jack  Nelson  has  been  photographed 
just  as  much,  if  not  more  than  any  other 
star  in  the  radio  business.  He  likes  the 
picture  above  best.  Of  course,  he  doesn't 
try  to  appear  so  serious  when  he's  sing- 
ing a  new  ditty  at  Mooseheart,  111., 
where  WJJD  is  located. 

for  the  Bissell  Weisert  Piano  Company  of 
which  J.  Elliott  Jenkins  was  a  member. 
Upon  hearing  Jack  play,  Jenkins,  who 
was  one  of  the  owners  of  WDAP  on  the 
Drake  Hotel,  invited  him  up  to  play  and 
sing  and  the  requests  that  flowed  in  follow- 
ing that  first  appearance  predicted  great 
things  for  him  in  a  radio  way. 

At  that  time  Ralph  Shugart,  better 
known  as  "The  Sheik  of  the  Drake,"  was 
the  operator  and  announcer  and  a  very 
popular  one  at  that.  The  Radio  fans 
wondered  at  that  time  about  the  sudden 
disappearance  of  the  "Sheik"  and  Jack 
tells  us  that  this  is  the  first  time  any 
explanation  has 
appeared  in  print. 
We  do  this  know- 
ing that  it  is  now 
become  a  great 
joke  between  the 
team  of  Nelson 
and  Shugart,  and 
there  is  many  a 
laugh  over  it.  It 
seems  that  Thorne 
Donnelly,  the 
other  owner  of  the 
station,  was  very 


CUnique  Shield  is  To  Be 
Awarded  the  Final 
Winner  Very- 
Soon 

anxious  for  some  word  to  come  that  the 
station  had  been  heard  over-seas.  As  a 
joke,  Ralph  fixed  up  a  cablegram,  stating 
that  WDAP  had  been  heard  at  such  and 
such  a  time  by  the  operator  at  Burndept, 
London.  Immediately  upon  receipt  of  it 
Donnelly  communicated  with  all  the 
newspapers  and  a  good  story  was  started 
before  Ralph  had  a  chance  to  tell  him  it 
was  a  joke.  Donnelly  could  not  see  the 
joke,  however,  and  Jack  Nelson  was  put 
on  the  pay-roll  as  Announcer.  It  was  not 
long,  however,  before  Ralph  was  back  in 
the  fold,  later  becoming  Chief  Operator 
and  Engineer  of  WGN,  which  position  he 
resigned  to  become  engineer  of  WJJD,  to 
retain  the  fanciful  double-play  combi- 
nation, Nelson  to  Shugart  to  the  World. 

While  at  the  Drake,  Jack  Nelson  be- 
came more  and  more  popular  for  his  an- 
nouncing, his  playing  and  his  singing  and 
several  popular  songs  added  to  his  fame. 
"Foolish  Child,"  "I've  Got  A  Song  For 
Sale,"  "After  The  Storm,"  "You're  Too 
Sweet  For  A  Dream,"  and  "May  You 
Laugh  In  Your  Dreams,"  are  the  better 
known  of  his  compositions. 

Jack  Nelson's  own  story  of  Mooseheart 
appeared  in  a  recent  issue  of  RADIO 
AGE  and  he  assures  us  that  by  the  time 
this  story  is  in  print  he  will  be  presenting 
programs  from  the  Garod  Studio  in  the 
Palmer  House,  Chicago,  every  night, 
beginning  at  10:00  o'clock,  so  that  radio 
fans  will  again  hear  him  as  he  signs  off 
every  night,  singing  in  his  own  way,  his 
own  song,  "May  You  Laugh  In  Your 
Dreams!" 

THE  WINNER  FOR  DECEMBER 

Jack  Nelson Announcer  --..WJJD,  Mooseheart 

WINNERS  OF  PRECEDING  MONTHS 

July... _ ...Duncan  Sisters 

August , Bill  Hay 

September Karl  Bonawitz 

October H.  W.  Arlin 

November ..Bert  Davis 

STANDING  TO  DECEMBER   15th 
Name  Classification  Where  Heard 

Karl  Bonawitz  ...Organist WIP,  Philadelphia 

H.  W.  Arlin Announcer  ....KDKA,  Pittsburgh 

Bill  Hay —Announcer  ....KFKX,  Hastings 

Bert  Davis.._ Entertainer.... WQJ.  Chicago 

Jack  Nelson Announcer  ....WJJD,  Mooseheart 

Duncan  Sisters  ..Entertainers. .KYW,  Chicago 

Lambdin  Kay Announcer  ....WSB,  Atlanta 

J.    Remington 

Welsch Organist KYW,  Chicago 

John  S.  Dagget  ..Announcer  -...KHJ,  Los  Angeles 

E.  L.  Tyson Announcer  ....WWJ,  Detroit 

Ford  &  Glenn Entertainers..WLS,  Chicago 

Harry  M.  Snod- 

grass Entertainer....WOS,  Jefferson  City 

Fred  Smiths Announcer  ....WLW,  Cincinnati 

Jerry  Sullivan  ....Announcer- 

Entertainer..WQJ,  Chicago 
Nick  B.  Harris... .Entertainer.... KFI,  Los  Angeles 

Art  Linick Entertainer..._KYW,  Chicago 

Hired  Hand -Announcer WBAP,  Fort  Worth 

Edw.  H.  Smith Director- 
Player WGY,  Schenectady 

Wendell  Hall Entertainer._.WDAF,  Kansas  City 

Others  Gaining  Too 

IT  will  be  noted  from  the  above  that  in 
addition  to  Jack   Nelson,  substantial 
gains  were  made  by  Nick  B.  Harris  and 
Art  Linick.     Remember,  it  is  not  neces- 
(Tum  to  page  73) 


RADIO  AGE  for  February,  1925 


What  the  Broadcasters  are  Doing 


33 


MEET  our 
RADIO  MOTHER 

By  NENA  WILSON  BADENOCH 

From  Coast  to  Coast,  America  s 
Housewives — andHubbies  too, Look 
to  This  Amiable  Home  Expert  for 
the   Latest    in    the   Culinary    Art 


GOOD  morning,  girls  and  boys." 
■  A  half  a  million  listeners  look 
forward  to  that  cheery  phrase 
at  11:35  a.  m.,  every  day  from  KYW, 
Chicago.  It  comes  from  Anna  J.  Peter- 
son, broadcasting  menus  and  recipes  for 
the  day  from  the  Home  Service  Depart- 
ment of  The  Peoples  Gas  Light  &  Coke 
Co. 

Seated  in  her  private  office  before  the 
microphone,  Mrs.  Peterson  is  within 
sight  and  sound  of  her  Home  Service 
efficiency  kitchen  where  every  recipe 
she  gives  is  tested  and  tasted.  As  she 
talks  about  the  fragrant  odor  of  the  cook- 
ing food  it  seems  as  if  you  could  almost 
smell  it.  When  she  says  "delicious"  in 
that  effective  way  of  hers,  your  mouth 
fairly  waters.  Thousands  of  her  radio 
pals  have  told  her  so. 

"Why  say  'good  morning,  boys'?  I 
know  thousands  of  girls  are  listening 
but  I  doubt  the  boys,"  a  listener-in  said. 
But  Mrs.  Peterson  knows  from  the 
hundreds  of  letters  received  from  older 
men  who  no  longer  go  to  business,  from 
crippled  men  who  have  turned  house- 
keepers while   their  wives  have  become 


wage  earners — from  young  fellows  con- 
valescing, that  she  has  many  "boys" 
jotting  down  the  menus  and  recipes  for 
family  use.  In  her  big-hearted,  motherly 
way,  she  feels  they  are  a  very  important 
part  of  her  radio  family. 

Many  a  young  man  brings  his  bride-to- 
be  to  meet   Mrs.  Peterson. 

"How  did  you  happen  to  come?"  she 
asks  them  after  she  has  taken  them 
around  her  wonderful  department  and 
shown  them  her  spacious  auditorium 
where  daily  cooking  classes  are  held. 

"I  have  noticed  the  improvement  in 
Mother's  cooking  since  she  has  been 
listening  every  day  over  the  radio,"  is 
the  invariable  reply. 

"Ma  said  she  would  live  to  be  a  hun- 
dred if  she  had  had  this  service  when  she 
was  young,"  one  young  fellow  said,  and  so 
I  brought  Mary  in  to  get  started  right." 

All  the  Way  from  Maine 

\  PASTOR  from  Portland,  Maine, 
-i*-  while  passing  through  Chicago,  made 
a  point  of  coming  in  to  meet  Mrs.  Peter- 
son. "I  would  know  your  voice  any- 
where," he  said  after  the  first  greeting, 


The  "radio 

mother"  herself, 

Anna   J.  Peterson 


"for  I  have  heard  you  almost  every  morn- 
ing for  a  year.  My  wife  and  I  feel  so 
grateful  for  the  good  things  you  have 
brought  to  our  table  and  for  the  money 
you  have  saved  us,  that  I  promised  before 
I  left  home  that  I  would  come  in  and  tell 
you  so." 

So  generally  had  this  feeling  been  ex- 
pressed that  Mrs.  Peterson  decided  to 
give  a  radio  tea.  She  broadcast  her 
invitation  and  was  overwhelmed  with 
pleasure  at  the  response  which  she  re- 
ceived. Six  thousand  men,  women  and 
children  filled  the  large  auditorium  ad- 
joining rooms  of  the  Gas  Company,  so 
that  late-comers  had  to  be  turned  away 
(Turn  to  page  56) 


Miss  Grace  Haight, 
one  of  Mrs.  Peter- 
son's radio  assis- 
tants, preparing 
for  a  demonstra- 
tion of  "Canning 
of  Fruits  and  Veg- 
etables." Every- 
thing is  tested  be- 
fore being  broad- 
cast. 


& 


34  RADIO  AGE  for  February,  1925 


What  the  Broadcasters  are  Doing 

"Listening  In 

from 

Coast  to  Coast 


A  new  photo  of  Rosemary  Hughes,  winsome  soprano  who  keeps 
the  telegrams  flowing  regularly  into  Station  WGN,  Chicago. 


Lets 

Take  a 

Turn 

of  the 

Dials  and 

See 
What's  on 
the  Air 
Tonight 
at  Your 
Favorite 
Station 


going  full  blast  from  KDKA, 
East  Pittsburgh.  This  orches- 
tra is  a  pleasure  at  dinner  hour. 
The  only  trouble  is,  we  have  to 
wait  too  long  between  announce- 
ments of  numbers.  We  must 
pass  on,  even  at  the  expense  of 
hearing  KDKA's  superb  music. 


Remember  a  while  back  we 
said  WBZ  was  probably  broad- 
casting good  Eastern  symphony 
from  Boston?  We  weren't  far 
wrong.  This  station  is  coming 
in  strong,  with  a  fine  male 
quartette  singing  old-time  love 
melodies.  By  the  way  requests 
are  coming  in,  the  Easterners 
like  the  old  favorities.  Can't 
other  stations  take  the  hint? 


L 


ET'S  SEE.  It's  Tuesday  night.  A  good  night  for  Radio. 
Ready  for  a  spin  over  the  dials?  All  right,  folks;  let's 
see  who's  on  the  air. 


We  must  hurry.  Here's  WGN, 
with     its     unparalleled     dinner 
music  by  the  Drake  Hotel  Con- 
cert Ensemble  and   the    Black- 
stone  Hotel  String  Quintet,  Chi- 
cago.     Perhaps  the  best   string 
music  on  the  air.    And  then  Rosemary  Hughes  varies  the  early 
evening  program  with   a  soprano  solo.     A  dependable  radio 
star — is    Rosemary. 


Here's  the  Boston  Symphony  Orchestra 
from  WEAN,  broadcasting  from  Boston  through 
Providence.  Fine,  uplifting  programs  may 
always  be  heard  from  this  station.  The  cream 
of  the  Eastern  music  world  filters  from  Boston 
through  WEAN.  But  wait,  WBZ,  at  Spring- 
field, is  probably  getting  in  on  Boston's  orches- 
trations.    Remember  them  farther  up  your  dial. 


What's    that? 
Talk  about   jazz! 
close  second 


WMAK— Lockport,    N.    Y. 
This   station   is  running   a 


WTAS — at  286  meters,  only  a  couple  of 
points  up  from  WMAK.  A  jazz  orchestra — a 
jazz  singer — any  time  of  the  evening.  Can't 
you  see  the  syncopation  fairly  dripping  from 
WTAS'  aerial?  But  that  gets  tiresome.  Let's 
go  up  the  scale,  fans. 


What's  this?  All  over  the  house  and  the 
volume  only  half  on?  Not  Chicago.  The  an- 
nouncement tells  us  it's  the  Willard  Battery 
Station,  WTAM,  at  Cleveland. 

Oh,  yes,  that's  the  first  super-power  station. 
But  it's  easy  to  tune  out — five  hundred  miles 
away.  See?  A  twist  of  the  dial  and  it's  gone. 
But  get  WTAM  back.  Realizing  that  increased 
power  means  more  listeners,  voluntary  or  other- 
wise, WTAM  is  giving  us  some  wonderful  pro- 
grams. Some  fine  orchestra  music — some 
really  trained  voices.  Not  on  the  air  too  much, 
either.  Here's  more  power  to  super-power  if 
they're  all  like  WTAM! 


Here  is  Maj.  J.  Andrew  White, 
"most  popular  announcer"  from 
WJY—WJZ.  New  York. 


Here's  309  meters — and  a  fine  station.  It's  WSAI 
U.  S.  Playing  Card  Co.,  at  Cincinnati.  That 
announcer,  E.  S.  Mittendorf,  is  distinctive. 
We  can  hear  every  word  he  says.  And  if 
he  isn't  announcing  the  Duncan  Sisters!  They 
seem  to  behavingarollicking  time  in  the  studio. 
Lots  of  fun,  but  we  must  pass  on  .     .     . 


Here  we  are  at  319.  The  Hotel  Statler 
Orchestra  from  WGR,  Buffalo,  announced  in 
clear,  crisp  tones.  Followed  by  an  educational 
talk.  Good  stuff — that  mixing  the  music  and 
the  serious.  Interesting  data  on  the  growth 
of  New  York  State — we  digest  a  few  morsels 
and  turn  the  dials. 


It's  time  to  close,  so  we'll  hurry  up  the  scale 
to  WOS,  Jefferson  City,  Mo.  Yes — there's 
Harry     Snodgrass,     with     his    beloved     piano, 

singing  from  his  "guest  cell"  in  the  Missouri  state  penitentiary. 

Well,  he'll  be  a  free  man  January  16.  And  the  gifts  he's  get- 
of  the  ting!  Hundreds  of  dollars  in  cash — thousands  of  personal 
mementos.  Hundreds  of  offers  of  employment. 
We  wish  they'd  let  us  know  where  Harry'll  be 
after  he  leaves  confinement.  For  he  certainly 
must  stay  on  the  air. 

And  fans,  did  you  know  Harry  is  still  one  of 
the  leaders  in  the  RADIO  AGE  Radio  Favorite 
Popularity  Contest?  The  votes  are  still  com- 
ing in,  so  the  announcement  Harry  was  a  con- 
vict didn't  harm  his  popularity.  Rather,  it 
augmented  it.  More  power  to  him.  And  here's 
hoping  he's  among  the  winners  in  the  final 
RADIO     AGE     contest. 


The  Westinghouse  Little  Symphony  Orches- 
tra, one  of  the  best  to  be  heard  from  radio,  is 


Miss  Edith  Bennett,  acknowledged 
the  woman  with  the  "perfect  feminine 
radio  voice.''     Ever  hear  her? 


If  you  haven't  voted  in  the  contest  yet,  there's 
a  coupon  in  this  issue. 

Signing   off — we'll   continue   our  journey  la 
an   early   issue. 


RADIO  AGE  for  February,  1925 


What  the  Broadcasters  are  Doing 


35 


Who's  the  RED-HEADED  Girl? 

An  Attempt  to  Identify  WFAA's  "Mystery  Woman" 


THE  "Red-Headed  Girl"  who  enter- 
tains    you     over     Radio     Station 
WFAA,   Dallas,  Texas,  steadfastly 
maintains  that  she  has  no  other  name. 

This  is  not  true,  however.  She  has  such 
a  pretty  name  I  am  tempted  to  tell  you 
what  it  is;  but  she  threatens  never  to  ap- 
pear on  the  radio  again  if  I  do. 

Therefore,  I  am  not  going  to  tell  and 

deprive  you  of  the  pleasure  she  has  so 

generously  given  her  audience  heretofore. 

"Why    do    you    refuse    to    give    your 

name?"     I  asked  her. 

She  Loathes  Publicity. 

"I  do  not  like  publicity.  Of  course,  as 
long  as  I  can  hide  my  real  identity,  I  do 
not  mind  it  so  much,"  she  answered. 

Miss  Red-Head  was  surely  born  under 
a  lucky  star,  as  nice  things  seem  to  hap- 


By  LERA  McGINTY 


pen  to  her  daily.  Don't  you  think  it  is 
lucky  to  have  beautiful  red  hair  and  not 
the  remotest  sign  of  a  freckle? 

Her  complexion  has  not  been  accom- 
plished by  lemon  lotions  or  by  sitting  in 
the  shade,  for  she  plays  golf  every  minute 
that  she  can  spare.  That  also  accounts 
for  the  sparkle  in  her  deep  brown  eyes. 

Contrary  to  the  general  opinion  formed 
of  red-headed  people,  this  young  lady  has 
a  charming  disposition.  True,  I  was  not 
with  her  long,  but  she  had  a  cold — a  bad 
cold —  yet  she  was  as  jolly  as  a  fat  man. 
(Don't  get  the  impression  that  she  is  fat. 
She  isn't;  and  she  is  little  but  not  too 
little!) 


VXTHEN  she  was  asked  how  her  radio 
1  *  popularity  came  about,   it   brought 
forth  this  story  of  three  years  ago. 

"A  friend  of  mine  was  society  editor  on 
a  large  Texas  daily,  and  she  had  to  be 
away  for  a  few  weeks.  She  asked  me  to 
work  for  her,  but  I  did  not  dream  of 
really  doing  it.  I  knew  nothing  about 
newspaper  offices  and  I  had  never  used  a 
typewriter,  but  she  insisted  that  I  could 
do  it.  With  a  rented  typewriter  and  her 
help  I  was  able  to  impress  the  editor  at 
the  end  of  three  weeks  that  I  was  just 
the  person  he  needed." 

Her  Past— Shh! 
That  was  three  years  ago,  and  in  that 
length   of  time   the   "Red-Headed   Girl" 
has   made   a   place   for   herself  in    news- 
paperdom. 

(Turn  to  page  58) 


36 


RADIO  AGE  for  February,  1925 


What  Che  Broadcasters  are  Doing 


At  the  right  is  Detroit's  newest 
pride,  the  Book -Cadillac  Hotel, 
the  world's  tallest  hotel  and  home 
of  WCX's  new  studio.  In  the  circle 
is  the  ever-popular  Kdgar  A. 
Guest,  whose  verses  helped  in- 
augurate the  new  studio  last 
month. 


Detroit  Pauses 

d. Impressive  Ceremonies 

By  MILTON 


PERCHED  thirty-two  stories  up  in 
the  air,  Radiophone  WCX  of  the 
Detroit  Free  Press  broadcast  to  the 
world  the  opening  of  the  world's  tallest 
hotel  on  December  8.  It  was  the  Book- 
Cadillac  Hotel,   Detroit's  latest  pride. 

The  whole  city  had  been  waiting  for 
the  Free  Press  station  to  open  again,  for 
it  had  shut  down  for  the  week  while  the 
apparatus  was  being  moved  from  the 
Press  building  to  the  magnificent  hotel. 
But  the  opening  was  worth  it,  as  all  the 
celebrities  of  the  city  were  present,  and 
John  Smith,  mayor  of  Detroit,  and 
Edgar  Guest,  the  famous  poet,  stood 
before  the  microphone  and  let  the  city 
hear  their  voices. 

Tust  at  this  time  it  would  not  be  amiss 


to  tell  a  bit  of  my  experiences  in  getting 
at  this  station  to  report  it  for  the  readers 
of  RADIO  AGE.  Don't  think  it  was  a 
cinch. 

Everybody  Aglow 

YOU  see,  the  whole  city  had  been 
waiting  for  months  and  months  to 
see  the  famous  hotel  in  its  completion, 
and  hear  the  station.  The  Book  family 
and  the  Cadillacs  are  very  well  known 
citizens  and  consequently  there  was  a 
great  deal  of  interest  attached  to  their 
venture.  (As  a  matter  of  note,  it  may 
be  mentioned  that  this  project  broke 
the  pocket-books  of  neither  the  Brooks 
nor  the  Cadillacs.  After  being  in  the 
city  for  a  day,    I   discovered  that  these 


capitalists  own  half  the  town  and  have 
enough  money  to  snap  their  fingers  at 
Henry  Ford's  bank  account.) 

This  opening  night  was  not  for  the 
public.  It  was  to  be  a  private  reception 
and  only  the  top  ladder  of  society  folk 
were  invited.  They  came  by  invitation 
and  partook  of  a  ten-dollar-per-plate 
feed. 

I  got  an  invitation,  but  the  ten  dollar 
feed  meant  nothing  to  me.  I  had  filled 
up  in  a  one-arm  joint  across  the  way. 

All  went  well,  the  writer  rejoicing 
that  he  had  got  past  the  big  footman 
while  the  common  folk  without  passes 
were  kicked  out.  But  I  discovered  that 
I  was  the  only  male  person  there  without 
a  full-dress  suit.     I  felt  pretty  bad  until 


RADIO  AGE  for  February,  1925 


What  the  Broadcasters  are  Doing 


37 


The  jovial  boys  at  the  left 
form  the  Hudson  Male  Quartette, 
which  is  now  a  regular  feature 
from  the  Book-Cadillac  Studio 
of  WCX,  Detroit.  Top  row, 
left  to  right:  Harry  A.  Leiter, 
and  Harry  E.  Parker;  bottom 
row:  Joseph  Kendrick  and  Har- 
rison Burch.  Below  is  Miss 
Carmen  Morlock,  of  the  Hudson 
Female  Quartette,  who  is  out  to 
prove  that  men  aren't  going  to 
monopolize  the  new  WCX. 


for  Station  WCX 

at  Book-Cadillac  Studio 


LIEBERMAN 


I  discovered  another  culprit  wearing  a 
business  suit.  I  thought  it  was  another 
low  person  like  myself  until  I  discovered 
that  it  was  none  other  than  Edgar 
Guest,  the  second  "James  Whitcomb 
Riley."  There's  a  real  fellow.  Miss 
Lucille  O'Connell,  program  director  of 
WCX,  introduced  me  to  him,  and 
to  his  little  boy,  a  lad  of  about  ten  years, 
who  is  being  brought  up  to  be  the  same 
inspiring,  democratic  man  his  father  is. 

Eddie  Thrills  'Em 

(~^  UEST  read  a  number  of  his  well-known 


Or 


poems    over    the    microphone    and 


when  I  looked  out  of  the  thirty-second 
story  window  I  thought  I  saw  the  vast 
city  underneath  vibrating  with  applause. 


His  stuff  is  great  and  he 
reads  it  wonderfully,  and 
some  of  the  evening  dress 
boys  in  the  outer  room 
smiled  and  moved  their 
heads  as  though  to  say: 
"He's  got  the  stuff,  all 
right." 

Preceding  Guest,  the 
mayor  spoke  and  he  said  how  proud  he 
was  to  be  at  the  head  of  a  city  which 
possessed  such  a  great  hostelry.  Then 
the  Hudson  Double  Quartet,  a  famous 
organization  in  Detroit,  sang  a  group  of 
musical  selections.  Each  one  of  them  is 
a  soloist,  and  the  organization  is  a  com- 
bination of  the  Hudson  Male  Quartet 
and  Female  Quartet.     They  were  accom- 


panied    by     Harrison     Burch,     concert 
pianist. 

Music  from  Jean  Goldkett's  orchestras, 
playing  in  the  dining  room  of  the  hotel 
downstairs,  interspersed  the  numbers. 
Goldkett's  orchestras  are  probably  des- 
tined to  become  about  the  best  known  in 
the  air,  now  that  WCX  is  going  full 
(Turn  to  page  59) 


38  RADIO  AGE  for  February,  1925 

How  One  Song 
Brought  Radio 
Fame !  Jt 


What  the  Broadcasters  are  Doing 

And  It  Happened 
^^         On  a  Sleepy 
^ik  Street-Car 


The  Radio  Life  of  Banks  Kennedy 

"If  I  Can  Arrange  It" 


By  RUSSELL  H.  HOPKINS 


"I'm  an  arranger, 
A  first  class  arranger 
The  best  in  the  land,  can't  you  see? 
There's  hardly  a  thing  in  this  wide,  wide 

world, 
That  hasn't  been  arranged  by  me." 

ON  A  slow-moving  Cottage  Grove 
av.  street-car,  one  day  last  fall, 
a  young  and  promising  lad  named 
Banks  Kennedy  scribbled  off  the  fore- 
going paragraph.  Not  that  he  didn't 
have  anything  else  to  do;  in  fact,  he  was 
organist  at  one  of  Chicago's  biggest  movie 
palaces,  a  leading  instructor  in  the  art 
of  piano  playing,  and  a  leader  in  the 
University    of    Chicago's    "social    elect." 

But  he  felt  in  a  composing  mood  and 
lie  decided  to  write  something  to  ease 
the  agony  of  the  aforementioned  slow- 
moving  street  car. 

That  was  about  three  months  ago. 
Then  one  day  a  Sigma  Alpha  Epsilon 
fraternity  brother  of  Kennedy's,  Harry 
Aldyne  by  name — and  incidentally  the 
contest  editor  of  RADIO  AGE — asked 
him  if  he  would  like  to  entertain  over 
Radio  Station  KYW  the  coming  Wed- 
nesday. Banks,  eager  for  a  new  thrill, 
consented. 

His  Radio  Debut 

ONE   Wednesday   night   at    8   o'clock, 
Banks     Kennedy     made     his     radio 


debut.  He  was  displeased  that  the 
program  was  strictly  classical,  but  the 
RADIO  AGE  program  directors  saw 
under  Kennedy's  unwillingly  serious 
exterior  a  gift  for  jazz  and  light  enter- 
tainment that  would  lead  him  to  untold 
heights  in  the  radio  world. 

With  that  thought  in  mind,  and  heed- 
ful of  Kennedy's  success  even  at  the  more 
serious  side  of  radio  endeavor,  Harry 
Aldyne  asked  the  young  pianist  to  make 
his  "jazz  debut"  at  Station  KYW's 
jazz  carnival,  beginning  at  midnight  one 
Saturday  in  November. 

Banks'  eyes  sparkled.  Here's  where 
he'd  show  'em!  Here's  where  he'd  bring 
out  his  limitless  repertoire  of  toe-ticklers 
and  fancy-capturers! 

"I'll  be  there — if  I  can  arrange  it," 
Banks  told  Aldyne.  And  therein  was 
born  the  germ  of  an  idea — an  idea  that 
first  began  to  take  shape  in  Kennedy's 
nimble  brain  on  a  slow-moving  Cottage 
Grove  av.  street  car. 

Banks  "arranged  it."  He  introduced 
his  "If  I  Can  Arrange  It"  song — at 
least  the  first  three  hundred  verses — 
and  by  the  next  morning  hundreds  of 
radio  fans  were  writing  to  KYW  and 
asking  for  more!  That  assured  the 
song's  success,  so  Banks  assured  his 
radio    audience    at    least     50,000     more 


verses  would  be  forthcoming  within  a 
short  time. 

Later,  at  Station  WEBH,  under  the 
auspices  of  RADIO  AGE,  Banks  intro- 
duced several  more  verses,  three  times 
a  week  for  several  weeks.  The  song  is 
now  known  as  "Chicago's  radio  song," 
for  its  phenomenal  success  can  be  attrib- 
uted directly  to  Banks'  appearance  before 
the  microphone.  Within  a  short  time,  he 
promises,  it  will  be  in  sheet  music  form, 
with  as  many  verses  as  can  be  squeezed 
in  the  smallest  type  made.  That's  a 
promise! 

So  you  see,  Banks  owes  a  lot  to  radio. 
And  RADIO  AGE  takes  a  lot  of  the 
credit  for  putting  him  on  the  air  and 
showing  him  where  his  real  forte  lies. 

To  go  into  history,  Banks  is  a  South- 
erner by  birth.  Right  now,  in  fact,  he 
is  spending  the  first  weeks  of  the  new 
year  with  his  mother  in  Tuskalusa, 
Alabama.  Of  course,  Banks  can't  resist 
the  call  of  Radio,  so  while  he's  getting 
re-acquainted  with  the  old  homestead, 
he's  singing  from  WSB,  Atlanta;  WBAP, 
Fort  Worth,  Tex.;  and  WFAA,  Dallas, 
Tex.  And  it's  a  safe  bet  by  this  time 
that  all  the  lads  and  lassies  in  the  Sunny 
South  know  at  least  one  thousand  verses 
of  "If  I   Can  Arrange  It". 

We  trust  Banks  arranged  that  in  due 
time.  (Turn  to  page  61) 


RADIO  AGE  for  February,   1925 


The  Magazine  of  the  Hour  39 


"Compact  Efficiency"  with 

A  3-Tube  Reflex  Circuit 

By  JOHN  B.  RATHBUN 


Copyright:  1925 


REFLEX  circuits  have  always  had 
a  peculiar  fascination  for  me  be- 
cause of  the  opportunity  that  they 
offer  for  making  one  part  serve  the  pur- 
pose of  two  or  more  parts,  and  last  but 
not  least,  their  compactness  and  porta- 
bility. Further,  the  circuit  enables  us  to 
use  a  non-oscillating  detector  of  some 
description,  such  as  a  crystal  or  a  two 
element  tube,  and  this  gives  the  reflex 
first  rank  as  a  receiver  giving  clear,  dis- 
tortionless reception  with  almost  crystal- 
like tone.  All  the  advantages  of  radio 
frequency  and  audio  frequency  ampli- 
fication are  had  with  one  set  of  tubes,  and 
hence  with  fewer  tubes  than  with  a 
straight  radio  frequency  set. 

For  those  of  our  readers  who  have  not 
yet  studied  the  reflex  circuit,  I  will  give 
a  few  words  of  explanation  regarding  its 
workings  and  general  principles.  To 
begin  with,  the  radio  frequency  current 
received  from  the  aerial  is  amplified  at 
this  high  frequency  by  the  tubes,  and  is 
then  passed  through  some  sort  of  de- 
tector which  rectifies  the  waves  and  de- 
velops the  audio  frequency   phase,  just 


A  Circuit  that  Gives 
More  Amplification 
Output  than  Usual 
5-Tube  R.  F.  Outfits 

as  in  the  first  stages  of  a  radio  frequency 
receiver.  However,  at  this  point  a 
radical  change  is  made  in  the  circuit  for 
the  current  rectified  by  the  dectector  is 
now  returned  where  it  receives  a  second 
amplification  at  audio  frequency  in  the 
same  tubes,  increasing  the  volume  of 
sound.  Thus,  the  same  tubes  act  both 
as  audio  and  radio  frequency  amplifiers 
and  we  make  a  corresponding  saving  in 
the  number  of  tubes. 

Equivalent  to  5  Tubes 
TN  this  way,  two  tubes  with  a  crystal 
*-  detector  will  give  two  stages  of  radio 
and  two  stages  of  audio  amplification, 
approximately  the  equivalent  of  five 
tubes.       I    say  "approximately"  for  the 


reason  that  the  tubes  do  not  develop  their 
full  efficiency  under  these  conditions 
when  amplifying  at  two  frequencies,  but 
at  any  rate  they  develop  far  more  than 
the  same  number  of  tubes  under  any  other 
conditons.  Working  in  this  way  the 
tubes  probably  develop  80  per  cent  of 
their  full  capacity  as  radio  frequency 
amplifiers  and  90  per  cent  of  their  ca- 
pacity as  audio  amplifiers.  The  total 
actual  delivery  can  be  taken  at  about  75 
per  cent  of  the  full  tube  capacity.  A 
single  tube  reflex  should  give  the  equiva- 
lent of  one  stage  of  radio  and  one  stage  of 
audio,  but  as  we  know,  this  is  not  at- 
tained. Both  the  volume  and  range  are 
somewhat  better  than  a  single  tube 
regenerative,  both  in  regard  to  range  and 
volume,  but  are  not  equal  to  the  full  three 
tubes  used  in  amplifying  the  regenerative. 
Our  present  three  tube  reflex  circuit 
has  three  amplifying  tubes  and  a  crystal 
detector.  With  the  circuit  arranged  as 
shown,  this  is  the  theoretical  equivalent 
of  three  stages  of  radio  frequency  ampli- 
fication and  two  stages  of  audio  ampli- 
fication, or  better  than  the  output  of  the 


Blueprints   of  the  3-Tube  Reflex  on  Pages  40,  41,  44,  45 


A  Thirty-Two  Page  Blueprint  Section  in 

RADIO  AGE  ANNUAL  FOR  1925 

A  Technical  Radio  Section,  illustrated  with  real  blueprints  that  have  made  RADIO  AGE  the  radio  technician's  guide, 

is  the  predominating  feature  of  the  RADIO  AGE  ANNUAL.     Never  equalled  before  in  any  magazine.     The  sixteen 

full  page  blueprints  reproduced  in  the  ANNUAL  are  worth  many  times  the  price  of  the  book. 

Also,  scores  of  technical  diagrams,  pictures  and  especially  picked  constructional  articles.     Departments  for  beginner, 

experimenter  and  expert. 

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RADIO  AGE  for  February,  1925 


(  Continued  from  page  39) 
usual  five  tube  tuned  radio  frequency  out- 
fit. Actually,  this  gives  just  about  the 
same  performance  as  a  five  tube  set  with 
two  radio  stages,  detector  and  two  audio 
stages.  The  full  output  of  the  three 
theoretical  radio  stages  is  not  quite 
realized.  The  use  of  a  crystal  detector 
in  place  of  a  three  element  tube  detector 
eliminates  one  tube  and  greatly  improves 
the  tone,  but  at  the  same  time  the  volume 
issomewhat  diminished.  However,  the  loss 
of  volume  is  not  so  very  great  and  would 
hardly  justify  the  addition  of  another  tube. 

If  the  crystal  is  not  desired,  a  two 
element  tube  such  as  the  diode  can  be 
substituted,  but  a  standard  three  element 
tube  is  not  desirable  for  the  reason  that 
it  introduces  tube  noises,  regeneration 
and  other  factors  which  interfere  with 
the  clarity  of  reception.  There  are  many 
good  crystals  on  the  market  which  give 
little  trouble  in  a  reflex  circuit,  but  I 
must  caution  you  against  the  use  of  a 
galena  crystal  or  any  other  soft  crystal 
of  similar  nature.  Galena  will  not  stand 
up  under  the  high  plate  currents  of  a 
three  tube  reflex  but  will  burn  out  con- 
tinuously. It  is  all  right  on  a  crystal  set. 
but  not  with  from  5  to  IS  milliamperes 
current  driving  through  it. 

As  more  than  two  stages  of  audio 
amplification  are  not  advised  on  a  reflex 
circuit,  this  set  is  reflexed  in  such  a  way 
that  only  two  stages  are  employed,  the 
two  last  tubes  acting  as  both  audio  and 
radio  amplifiers  while  the  first  tube  is 
purely  a  radio  frequency  tube.  This  ar- 
rangement increases  the  radio  frequency 
amplification  efficiency  somewhat  and 
with  but  little  loss  in  audio. 

Description  of  Circuit 

BOTH  Fig.  1  and  Fig.  2  show  the  same 
circuit  but  in  different  ways.  Fig, 
1  is  the  so-called  conventional  circuit 
with  standard  symbols  for  the  more 
experienced  builder,  while  Fig.  2  is  a 
picture  diagram  for  the  novice.  Fig. 
3  is  a  panel  layout  showing  arrangement 
of  controls  and  approximate  spacing  of 
the  panel  mounted  apparatus  while  Fig.  4 
is  an  isometric  view  made  for  the  purpose 
of  showing  how  the  apparatus  actually 
looks  back  of  the  panel.  For  making  the 
actual  wiring  connections,  however,  I 
strongly  advise  the  wiring  in  either  Fig. 
1  or  Fig.  2  be  used,  as  many  of  the  wires 
are  concealed  in  the  isometric  view. 

Now,  looking  at  either  Fig.  1  or  Fig.  2, 
we  see  the  three  amplifying  tubes  T-l, 
T-2  and  T-3.  These  may  be  either  UV- 
201A  or  UV-199  tubes,  but  the  WD-12 
and  WD- 11  are  not  effective  for  this  pur- 
pose. Two  rheostats  are  used  for  the 
three  tubes,  one  for  the  first  radio  stage 
(T-l)  at  (R-l)  and  rheostat  (R-2)  for  the 
control  of  the  two  rear  reflexed  tubes 
(T-l — T-2).  A  plate  voltage  of  90  volts 
is  supplied  by  the  "B"  battery  to  all  of 
the  tubes  alike. 

All  of  the  radio  frequency  stages  are 
coupled  by  the  three  radio  frequency 
transformers  (Air  core  type)  marked 
RT-1,  RT-2  and  RT-3.  For  maximum 
results  these  should  be  of  the  tuned  radio 
frequency  type  tuned  by  the  17  plate 
(0.00305  mf)  variable  condensers  C2,  C3 
and   C4  as  in  the  neutrodyne,  or  other 


radio  frequency  type  receivers.  These 
condensers,  together  with  the  0.0005  mf 
loop  tuning  condenser  (CI)  give  extreme 
selectivity  and  a  maximum  peak  of  ampli- 
fication, but  at  the  same  time  they  make 
tuning  correspondingly  difficult  because 
of  the  many  controls  to  be  handled. 
Thus,  we  have  four  tuning  dials  which 
make  tuning  rather  difficult  for  the  novice. 


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THE  RADIO  AGE 

ANNUAL 
FOR  1925 

How  to  Read  Hookups. 
Something  the  beginner 
cannot  do  without. 

How  to  understand  Ra- 
dio Phenomena.  For  the 
fan  who  would  like  to 
know  something  about 
the  secrets  of  Radio. 

Building  your  first  Sim- 
ple Set.  Getting  started 
in  Radio. 

Your  First  Tube  Set.  A 
popular  reflex  circuit  de- 
veloped to  its  simplest 
degree. 

The  First  Baby  Hetero- 
dyne. Every  fan  will  want 
this. 

Thirty -two  Page  Radio 
Age  Annual  Blueprint 
Section,  with  sixteen  pages 
of  real  blueprints  in  color. 
Blueprints  of :  Single  tube 
sets,  Neutrodynes,  Reflex 
receivers,  New  Baby  Het, 
and  a  Wonder  Super-Het- 
erodyne. 

"How  to  Make"  articles 
on  Loud  Speakers,  Ampli- 
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How  to  Make  a  Real 
Super-heterodyne. 

And  many  other  articles, 
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To  avoid  the  use  of  so  many  condenser 
controls,  the  last  transformer  (RT-3) 
can  be  of  the  untuned  type  (Fig.  1)  and 
by  this  method  the  variable  condenser 
(C4)  can  be  omitted  as  suggested  by  the 
dotted  lines.  This  occasions  a  slight  drop 
in  the  effectiveness  of  the  circuit,  but  is 
usually  advisable  with  sets  operated  by 
beginners.  An  untuned  radio  frequency 
transformer  is  shown  at  (RT-3)  in  Figs. 
2,  3,  4.  All  the  other  stages  are  con- 
trolled or  tuned  across  the  secondary, 
which  gives  us  three  tuning  controls  in- 
cluding the  loop  tuner  (CI).  A  standard 
loop  aerial  is  connected  across  (Al)  and 
(A2)  in  the  usual  manner. 

Any    standard    air   core    radio    tuned 


The  Magazine  of  the  Hour 

frequency  transformer  or  neutrodyne 
transformer  can  be  used  at  RT-1,  RT-2 
or  RT-3.  The  primary  winding  (Y)  con- 
sists of  about  12  turns  of  No.  26  D.S.C. 
wire  while  the  secondary  has  about  64 
turns  of  the  same  size  wire.  However,  I 
recommend  that  these  transformers  be 
purchased  ready-made,  for  home  made 
transformers  are  seldom  reliable.  Fig. 
4A  shows  the  general  dimensions  of  the 
transformers  in  case  the  home  builder 
desires  to  "roll  his  own."  Transformer 
RT-3,  if  of  the  untuned  type,  must  be 
purchased,  as  this  type  is  altogether  out 
of  the  amateur  builder's  class. 

200  or  400  Ohm  Potentiometer 

AT  (PO)  we  have  a  200  or  400  ohm 
-*■*■  potentiometer  used  for  varying  the 
grid  potential  on  the  first  radio  frequency 
tube,  and  the  radio  frequency  resistance 
is  reduced  by  the  bypass  condenser  (Kl) 
which  has  a  capacity  of  not  less  than 
0.006  mf. 

At  the  extreme  right  in  Fig.  1  is  the 
crystal  detector  (CD)  in  series  with  the 
secondary  coil  (X)  of  the  radio  frequency 
transformer  (RF-3).  There  is  little  re- 
quiring further  explanation  at  this  point 
than  to  say  that  the  crystal  circuit  con- 
nects to  the  primary  coil  (P-B)  of  the 
first  audio  frequency  transformer  (AT-1). 
The  leads  running  from  (a)  and  (b)  to  the 
terminals  (P)  and  (B)  of  the  audio  trans- 
former (AT-1)  should  be  temporary 
wires  at  first  so  that  the  connections  (a) 
and  (b)  can  be  reversed  in  case  of  the 
transformer  coils  bucking.  First,  try 
them  in  the  position  shown  and  then 
reverse  (a)  and  (b)  to  determine  the  best 
working  position. 

At  (AT-1)  and  (AT-2)  are  the  two 
audio  frequency  transformers  acting  as 
the  first  and  second  stages  respectively 
of  the  audio  amplification  phase.  Trans- 
former (AT-1)  is  reflexed  into  the  second 
tube  (T2)  while  the  transformer  (AT-2) 
is  reflexed  into  the  third  tube  (T3). 
Both  transformers  are  of  the  usual  iron 
core  audio  type  with  a  ratio  of  from  5-1 
to  6-1.  Higher  ratios  are  not  generally 
advised  while  lower  ratios  reduce  ampli- 
fication, but  give  clearer  reception.  One 
of  the  most  valuable  features  of  the 
reflex  circuit  is  its  clear  tone  and  there- 
fore we  should  not  impair  this  feature  by 
using  poor  or  high  ratio  transformers. 

Both  secondary  and  primary  windings 
of  both  transformers  are  by-passed  by 
the  fixed  condensers  (K2-K3-K4-K5) 
which  are  of  0.002  mf  capacity  for  the 
majority  of  audio  transformers.  How- 
ever, some  transformers  have  so  much 
distributed  capacity  that  these  con- 
densers will  not  be  necessary  for  by- 
passing the  radio  frequency  current,  and 
in  fact,  some  transformers  work  better 
without  any  bypass  condensers  at  all. 
This  is  a  point  that  you  must  work  out 
experimentally  by  yourself  for  your  par- 
ticular conditions,  but  I  advise  you  to 
try  the  effect  of  the  condensers  at  any 
rate.  Another  fixed  condenser  (K6)  of 
0.5  mf  capacity  connected  between  the 
output  post  (p)  and  the  (  +  A)  is  useful  in 
reducing  the  "B"  battery  resistance  and 
the  speaker  impedance  offered  to  the 
radio  frequency  current. 

(Turn  to  next  page) 


RADIO  AGE  for  February,   1925 


The  Magazine  of  the  Hour 


43 


A  Compact  Three-Tube 
Reflex  Set 

(Continued  from  preceding  page) 

Here  it  will  be  noted  that  the  ouput 
terminals  (p-p1)  are  in  series  with  the  "B" 
battery  and  plate  of  the  third  tube  (T3), 
where  the  point  of  full  amplification  is 
had.  As  this  part  of  the  circuit  conveys 
radio  frequency  current  as  well  as  audio 
it  will  be  well  to  use  binding  posts  at  (p) 
and  (p1)  instead  of  jacks,  for  the  capacity 
of  the  jack  blades  often  seriously  affects 
the  performance.  The  blades  of  the 
jack  are  close  together  and  act  as  a  fixed 
condenser  of  no  small  capacity.  When 
the  plugs  are  changed,  this  often  disturbs 
the  balance  of  the  circuit.  The  switch 
(SI)  is  in  the  negative  "A"  battery  lead 
and  should  be  used  for  cutting  out  the 
filament  current,  thus  avoiding  the  neces- 
sity of  turning  down  the  rheostats  and 
disturbing  the  adjustment  every  time 
that  the  set  is  put  out  of  service. 

Diode  as  a  Detector 

TN  Fig.  2 A  is  a  small  corner  of  the  circuit 
-*-  drawn  out  to  show  how  a  two  element 
diode  tube  may  be  used  instead  of  the 
crystal  detector.  The  relation  of  this 
sketch  to  the  main  diagram  can  be  easily 
traced  out  by  the  location  of  the  tube 
amplifier  (T3),  the  radio  frequency  trans- 
fromer  (RT-3j,  and  the  optional  variable 
condenser  (C4).  The  two  element  tube 
is  at  (D)  with  the  plate  (M)  and  the 
filament  (F).  The  negative  filament  of 
the  tube  and  the  plate  (M)  are  connected 
into  the  circuit  just  as  with  the  crystal. 
A  separate  single  1.5  volt  dry  cell  (DB) 
supplies  current  to  the  filament  of  the 
diode  tube  and  is  provided  with  a  second 
cutout  switch  (S2).  The  terminals  (a-b) 
are  connected  to  the  primary  coil  of  the 
audio  transformer  (AT-1)  as  before. 

This  diode  tube  introduces  no  dis- 
tortion into  the  circuit  and  "avoids  the 
necessity  of  adjusting  a  crystal.  Its  use 
is  optional,  but  is  shown  as  a  means  of 
obtaining  tone  value  without  a  crystal. 
As  the  diode  is  not  critical  to  filament 
voltage  or  current,  it  is  not  usual  to  use 
a  rheostat,  but  one  can  be  used  if  a 
higher  voltage  than  1.5  volts  is  employed. 

Almost  any  standard  loop  aerial  can  be 
used  with  excellent  results,  which  is 
within  the  wavelength  range.  It  is  tuned 
by  the  condenser  (CI),  which  for  safety's 
sake  can  be  a  23  plate  0.0005  mf  size 
instead  of  0.00035  mf  used  across  the 
transformer  secondaries.  The  loop  used 
in  my  experiments  was  a  two  foot  loop 
of  the  solenoid  type  having  15  turns  of 
lamp  cord.  This,  however,  is  simply  a 
suggestion  as  to  size.  Where  there  is 
much  interference,  the  loop  will  be  found 
quite  useful  in  tuning  out  local  stations 
because  of  its  directional  qualities. 
Three  stages  of  radio  frequency  will  in- 
sure good  reception  over  long  distances 
with  the  loop. 

Size  of  Panels,  Etc. 

My  first  set  was  mounted  on  a  special 
0  "xl3  "  panel  without  crowding  or  trouble 
feedbacks.  Further  constructions  showed 
that  everything  worked  out  well  on  a 
7"xl4"x3-16"  panel,  and  I   believe   that 


this  size  is  best,  everything  considered. 
If  the  panel  is  so  short  that  the  parts  are 
crowded  together,  then  there  will  be 
feedback  between  stages  or  between  the 
radio  transformers  (RT-1)  and  (RT-2). 
If  a  very  long  cabinet  is  used,  then  the 
wiring  will  be  so  long  that  the  losses  will 
be  materially  increased.  All  wires  should 
be  as  short  as  possible,  particularly  the 
wires  running  to  the  grid  posts  (G)  on  the 
sockets,  and  the  wiring  should  be  rather 
open  so  that  the  wires  do  not  come 
together  close  at  points  where  they  are 
parallel.  Don't  crowd  the  wiring  to- 
gether for  the  sake  of  appearances. 
Performance  is  of  more  importance  than 
appearance  on  back  of  panel. 

In  connecting  up  the  set,  be  sure  that 
the  stator  or  stationary  blades  of  the 
variable  condensers  marked  (S)  are  con- 
nected to  the  grid  side  of  the  circuit  as 
shown.  Again,  keep  the  audio  frequency 
transformers  as  far  out  of  the  field  of  the 
radio  frequency  transformers  as  possible; 
that  is,  do  not  place  the  audios  directly 
in  line  with  the  center  of  the  radio  fre- 
quency transformers. 

The  location  of  the  crystal  detector  is 
a  matter  of  personal  taste  and  judgment. 
Mounted  on  the  front  of  the  panel,  it  is 
easy  to  adjust,  but  it  is  also  more  likely 
to  be  knocked  out  of  adjustment  by  the 
hand  when  reaching  for  the  tuning  dials, 
and  the  wires  to  the  detector  are  also 
much  longer.  On  the  other  hand,  if  the 
detector  is  mounted  on  the  bottom  board 
in  the  rear,  it  is  difficult  to  adjust  and  is 
inconvenient.  There  is  no  marked  advan- 
tage either  way  except  for  those  people 
who  like  to  see  a  great  variety  of  appara- 
tus displayed  on  the  front  of  the  panel. 

Use  Vernier  Control 
/"^WIXG  to  the  sharp  tuning  of  the 
^-'  condensers,  it  is  advisable  to  use  a 
vernier  type  for  all  three  controls,  and 
the  true  low  loss  type  is  of  course  pre- 
ferable. Low  loss  type  air  core  trans- 
formers are  of  great  assistance  in  getting 
the  distant  stations  and  add  volume  on 
the  locals.  To  decrease  the  losses  further, 
use  good  sockets  having  a  high  insulating 
value  and  install  them  in  the  set  so  that 
the  bottom  of  the  sockets  is  at  least  1-4 
inch  above  the  bottom  board  if  a  wood 
bottom  board  is  used.  A  bakelite  or  hard 
rubber  panel  is  to  be  preferred  to  a  wood 
bottom  board  in  every  case,  as  there  is  as 
much  opportunity  for  high  frequency 
leakage  at  this  point  as  on  the  vertical 
panel  itself. 

Spaghetti  is  not  always  the  best  thing 
to  use  for  covering  the  wiring.  It  adds  to 
the  capacity  effect  of  the  conductors,  and 
in  a  way  offsets  the  care  that  has  been 
taken  against  leakage  and  inductive 
losses  at  other  points  in  the  circuit.  It 
has  always  been  amusing  to  me  to  see 
how  carefully  the  low  loss  coils  are  stripped 
of  dielectric  and  insulation  to  avoid  loss, 
and  then  how  a  spaghetti  dielectric  is 
deliberately  placed  on  a  much  longer 
length  of  wire  in  the  same  circuit,  thus 
completely  eliminating  the  advantages  of 
the  low  loss  coils. 

To  make  matters  worse,  the  spaghetti 
is  varnished  which  further  increases  its 
capacity  over  the  dry  wound  wire  of  the 
coils.      With   two   wires   run    parallel   to 


each  other  for  any  distance,  the  use  of 
spaghetti  has  a  marked  effect  on  the 
capacity  of  the  circuit. 

All  Tubes  Amplifiers 

ALL  tubes  are  amplifying  tubes, 
hence  a  plate  or  "B"  battery  voltage 
of  from  67.5  to  90  volts  is  used  on  the 
plates  for  maximum  amplification.  Lower 
voltages  than  these  will  give  very  poor 
results.  In  case  the  diode  tube  is  used 
as  a  detector,  please  note  that  no  "B" 
battery  is  applied  to  the  plate  of  this 
tube  for  the  reason  that  we  wish  to  avoid 
oscillation  in  the  detector  branch  of  the 
circuit. 

The  "A"  or  filament  current  voltage 
depends  upon  the  type  of  tube  used. 
For  the  UV-199  tube  the  applied  voltage 
is  4.5  volts  or  equal  to  the  voltage  of 
three  dry  cells  connected  in  parallel. 
For  the  UV-201A  tube  we  use  a  six  volt 
storage  battery.  While  the  UV-199 
tubes  do  not  give  quite  the  results  that 
are  obtained  with  the  storage  battery 
tubes,  yet  they  are  often  very  desirable 
where  a  storage  battery  is  impracticable. 
A  single  set  of  three  cells  in  series  will 
give  two  months  service  or  over,  but 
for  the  most  economical  service  I  suggest 
that  six  batteries  be  employed — two 
groups  of  three  cells  in  series. 

In  making  these  connections,  have  two 
rows  of  three  batteries  each  and  connect 
up  each  of  these  groups  independently 
in  series,  that  is,  zinc  to  carbon,  zinc  to 
carbon,  etc.  Next,  connect  the  two 
carbons  of  the  two  groups  together,  and 
then  the  two  zincs,  these  connections 
being  made  at  the  end  cells.  The 
result  is  that  we  have  decreased  the 
demand  on  each  cell  by  one  half  and  in 
so  doing  have  increased  the  life  about 
three  times.  Doubling  the  number  of 
cells  in  parallel  does  not  only  double 
the  life.  It  does  much  more  than  that; 
it  triples  the  life  at  a  cost  which  is  only 
double  that  of  a  single  set  of  three  cells. 

Rheostat  (Rl)  controls  the  current 
to  tube  (Tl)  only;  therefore  a  high 
resistance  rheostat  should  be  used,  sav 
15  to  20  ohms  for  the  UV-201A  tube 
and  30  ohms  for  the  UV-199  tube. 
Rheostat  (R2)  carries  the  current  for 
both  (T2)  and  (T3);  hence  its  resistance 
should  be  less  than  for  the  single  tube. 
From  seven  to  15  ohms  will  be  correct 
for  this  group. 

The  resistance  controls  are  not  critical 
as  with  detector  tubes,  and  therefore 
automatic  filament  control  devices  can 
be  employed  which  do  away  with 
rheostats  altogether.  This  has  certain 
advantages  and  disadvantages,  but  they 
can  be  used  if  desired  for  all  tubes,  using 
one  automatic  control  for  each  tube 
placed  in  the  negative  lead.  A  battery 
switch  must  be  used  with  this  arrange- 
ment, as  there  is  no  other  way  of  turning 
off  the  filament  current  except  by  dis- 
connecting the  "A"  battery.  With 
rheostats  the  switch  may  be  omitted  as 
the  rheostat  also  acts  as  a  switch,  but 
in  general  it  is  ad\dsable  to  use  a  battery 
switch  under  all  conditions,  particularly 
for  the  Diode  tube. 


Have  You  Seen  the 

Radio 

Cross- Word  Puzzle 

in  this  Issue? 


Blueprint   Figures  3  and  4  on  pages  44  and  45. 


W^O/M  ~7^Mt>i=/ 


m 


■I 


46  RADIO  AGE  for  February,   1925 

The 

Wandering 

Minstrel 

of 
Radio 


By 
L.  S.  WHITCOMB 


Nate  Coldwell,  the  "Joy 
Digger,"  Was  told  by  a 
Doctor  to  Get  Out  in  the 
Air;  Instead  He  Got 
"On  the  Air"  and  To- 
day He  Travels  from 
Radio  Station  to  Radio 
Station  Making  Others 
Happy;  Covers  5000 
Miles  in  Six  Months! 


NATE  COLDWELL,  who  calls 
himself  "The  Joy  Digger,"  and 
hails  from  Chicago,  has  made  a 
big  hit  with  New  England  radio  fans. 
Coldwell  is  a  real  20th  century  edition 
of  the  wandering  minstrel  and  is  one  of 
the  most  interesting  artists  on  the  air 
at  WEEI,  Edison  Light  Co.,  of  Boston, 
Mass.  While  Mr.  Coldwell  has  been 
traveling  in  the  East,  he  has  been  making 
his  headquarters  at  WEEI  and  has  made 
thousands  of  friends  with  his  songs  and 
stories. 

During  the  past  six  months  Coldwell 
has  covered  over  5,000  miles  in  his 
travels  around  the  country.  His  story 
of  these  wanderings  sounds  like  a 
Horatio  Alger  book.  He  came  East 
from  Chicago  about  three  years  ago  to 
attend  Dartmouth  College  at  Hanover, 
N.  H.  Here  his  health  failed  and  he  was 
ordered  by  physicians  to  quit  school 
and  stay  out  in  the  air.  Coldwell  not 
only  went  out  in  the  air;  he  went  the 
doctors  one  better  and  got  out  on  the  air! 

He  Croons  'Em 

While  his  voice  is  not  heavy,  it  is  of 
fine  quality  and  by  getting  close  to  the 


What  the  Broadcasters  are  Doing 


Here's  the  "Joy  Digger"  in  a  typical  pose  with  his  trusty  "Uke,"  crooning  an 
original  melody  to  "Bob"  Emery,  announcer  at  Station  WEEI,  Boston,  who  is  hold- 
ing the  microphone. 


"mike"  and  crooning  his  songs  he  is 
able  to  put  them  over  wonderfully.  All 
of  Nate's  numbers  are  original.  New 
Englanders  have  fairly  gone  crazy  over 
Coldwell.  His  song  "You  Can't  Fool 
Fate"  has  been  sung  over  and  over  again 
from  Station  WEEI,  and  every  time  he 
comes  back,  scores  of  telephone  calls  and 
telegrams  flow  into  the  studio  request- 
ing him  to  do  his  entire  repertoire. 

Just  where  Coldwell  is  at  the  present 
time  is  not  known  to  officials  of  WEEI. 
He  drops  down  to  that  station  about  as 
often  as  the  rain  visits  this  changeable 
New  England  climate.  His  last  appear- 
ance at  WEEI  was  the  night  of  the 
Harvard-  Dartmouth  football  game. 
Nate  had  seen  the  game  on  a  pass.  He 
had  seen  his  college  mates  trounce 
Harvard  and  he  was  in  rare  form. 

About  a  week  ago,  however,  officials  at 
the  Edison  Light  station  picked  up  Cold- 
well's  program  from  WGY,  General 
Electric  Company,  Schenectady.  At  that 
time  the  announcer  told  the  listeners — in 
that  Coldwell  was  on  his  way  to  the 
Pacific  Coast.  Wherever  he  is,  his 
friends  at  WEEI  know  that  he  is  headed 
for    the    nearest    broadcast    station    and 


also  are  sure  that  radio  listeners  within 
500  miles  will  be  royally  entertained. 

Back  Home  Again 

Just  a  few  weeks  ago  some  RADIO 
AGE  experimenters  heard  Coldwell  from 
WTAS,  Elgin,  111.,  which  shows  he's 
gradually  drifting  back  to  his  old 
haunts    near    Chicago. 

"The  Wandering  Minstrel"  is  known 
better  away  from  Chicago  than  in  it,  so 
middle  westerners  may  get  a  chance  to 
hear  him  "do  his  stuff"  after  all. 

In  his  extremely  youthful  days,  Cold- 
well  had  very  little  inclination  toward 
music  or  the  composition  thereof.  In 
fact,  his  proud  parents  had  long  ago  given 
up  any  hope  that  he  might  become  a 
second  Chopin  or  even  an  embryo 
Irving  Berlin. 

So  what  did  Nate  do  but  do  a  little 
composing  after  he  started  broadcasting! 
Of  course,  he  lays  claim  to  no  fame  for 
his  compositions,  but  it  has  to  be  ad- 
mitted that  they  are  all  exceedingly 
original  and  snappy. 

What  they  lack  in  beauty  of  tone  and 
arrangement,  they  make  up  for  in  pep 
and  originality. 


RADIO  AGE  for  February,  1925 


What  the  Broadcasters  are  Doing 


47 


At  the  right  is  a  facsimile 
reproduction  of  a  letter  sent 
to  RADIO  AGE  by  Herbert 
Hoover,  Secretary  of  Com- 
merce, in  acknowledgement 
of  an  editorial  published  in 
the  October  issue,  praising  the 
Secretary's  stand  in  demand- 
ing stabilization  of  radio 
conditions.  Above  is  a  re- 
cent photograph  of  Mr. 
Hoover. 


| 


December  5,  1924 


'.air.  Frederick  a.   Smith 
Radio  jige 

500  li.  Dearborn  St. 
Chicago,  111. 

Dear  fcr.  Strath: 

This  is  just  by  aay  or  expression" 

oi  Etppreei&tioa  for  yoyr  editorial  in  the  October 

iaaut.'  or  "Radio  -j^e"  which  .las  co.-:e  to  (cy  attention 

on  Dj  return  froa  the  ye^t.  Our  p;jrt  in  tne 

raoio  industry  ie  becoititi^  irore  difficult  every 

ironth  and  ae  certainly  co  n=ed  n:or<J  support. 


Yours  faithfully 


jtfjc~-<£x^-- 


-<t~Z~Z' 


48  RADIO  AGE  for  February,    1925 


The  Magazine  of  the  Hour 


ANHATTAN 

ELECTRICAL  SUPPLY  COJNC. 

MAKERS  OF  THE  FAMOUS 


(Wanhattan 
Junior  $IO 


LOUD    SPEAKER 


Oldest  and  Largest  Distributors  of 

ofjAmerk 


NEW  YORK 


114  SO.  WELLS  ST.,  CHICAGO 

ST.  LOUIS 


SAN  FRANCISCO 


*     Ttsted  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  February,  1925 


%  Hook^\3Lp^ 


*TpHE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  is 
■*■  contributed  by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  circuits 
and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points,  and 
it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


The  Magazine  vf  the  Hour  49 

'///a 


TV  TOW  that  we  are  over  the  holiday 

I  ^  season,  I  suppose  we  can  all  set- 
-*r  '  tie  down  and  start  twisting  the 
dials  with  a  vengeance  once  more.  How- 
ever, I  don't  want  our  readers  to  think 
that  we  imagine  any  one  has  laid  down 
on  the  job  during  the  past  month,  but 
during  this"  time  of  the  year  we  are  so 
occupied  with  other  duties  that  some- 
times the  DX  fans  are  too  tired  to  bother 
with  sending  in  their  lists  of  calls  re- 
ceived. 

Last  month  we  requested  that  our  con- 
tributors exercise  a  little  more  care  and 
neatness  in  submitting  material  for  this 
department.  It  really  is  gratifying  to 
notice  the  change  that  has  already  taken 
place.  No  more  do  we  receive  questions 
in  the  technical  department  written  on 
the  rough  side  of  a  shingle  or  the  margin 
of  a  newspaper.  Instead  they  are  sub- 
mitted in  a  nice,  orderly  manner,  and  it 
really  is  a  pleasure  for  the  editor  to  open 
his  mail  in  the  morning  and  know  that 
he  will  not  need  to  strain  his  eyes  in  an 
attempt  to  decipher  a  cryptic  message. 

Likewise  several  photographs  have 
been  received  and  the  only  thing  that 
prevents  our  printing  them  is  the  lack  of 
space.  Good  photographs  of  sets  or  sta- 
tions are  alwa3'S  welcome,  and  we  want 
to  receive  more  of  them.  It  goes  without 
saying  that  we  are  also  desirous  of  ob- 
taining stories,  entertaining  or  otherwise, 
for  this  page,  and  I  know  that  most  of  the 
amateurs  and  professional  operators  have 
a  flock  of  them  at  their  command,  that 
I  am  sure  will  come  pouring  in  once  the 
word  is  passed  around  that  the  Pick-ups 
editor  would  like  to  have  them. 

We  have  by  way  of  an  innovation  this 
month  a  contribution  from  a  lady  fan 
whom  we  think  must  be  a  regular  ex- 
perimenter, as  her  letter  seems  to  point 
to  the  fact  that  she  has  built  several  sets. 

We  certainly  welcome  her  contribution 
and  hope  that  we  shall  have  the  pleasure 
of  hearing  from  her  from  time  to  time. 

Any  number  of  good  DX  lists  have 
been  contributed  by  fans  who  are  desirous 
of  obtaining  the  well-known  DT  buttons. 
It  really  was  quite  hard  this  month  to 
choose  the  best  lists,  and  if  an>-  of  you  feel 
disappointed  because  you  have  been  left 
out,  do  not  be  discouraged,  but  try  again, 
as  the  above  list  contains  only  the  cream 
of  the  largest  number  of  letters  ever 
handled  through  the  Pick-ups  and  Hook- 
ups Department. 

If  you  will  look  through  our  Strays 
column,  you  will  notice  the  kind  of  re- 
ception that  was  necessary  to  get  into 
the  DT  column  this  month. 

Truly,  the  lads  who  have  been  honored 


f.  Mcdonald 

Chicago,  Ills, 


Name 
Chas.  C 


Drake- 


Roland  Lure... 


CONTRIBUTORS 

GILBERT  SLATER  TED  GERILL  EINAR  HULTMAN 

Pawtucket,  R.  L  St.  Louis,  Mo.  Jamestown,  N.  Y. 

DIAL  TWISTERS 

Address  City 

943  Gladstone  Ave* Detroit,  Mich. 

jl. _ — Newport,  N.  J. 

.184  Spring  St 

— .....Brooklyn,  N.  Y. 

Delmar,  Iowa. 

Milwaukee,  Wis. 

.Waynesville,  Ills. 


Marion  S.  Corly 

Wm.  B.  Simpson 445  Autumn  Ave.. 

Felix  Frederiksen Route  2 

Berney  Philippson.. ....631  55th  St^ 

E.  E.  Richmonds 

Roy  M.  Canfield 45  North  Park  St ....East  Orange,  N.  J. 

Einar  A.  Hultman 97  Baker  St ....Jamestown,  N.  Y. 

James  Grindle. 1143  Garfield  St Hammond,  Ind. 

Ted  Gerell 5327  Pershing  Ave St.  Louis,  Mo. 

Charles  H.  Dawson... ....14  Cavell  Ave. Toronto,  Ont.,  Can. 

Henry  W.  Schwab 201  Buell  St Muscatine,  Iowa. 

Wayne  Mac  Quiddy Drawer   "S"___ Pittsburg,  Calif. 

Otis  C.  Wyatt 57  Gladstone  St... .....Providence,  R.  I. 

Ralph  E.  Riley. _1711  Fifth  St Oakland,  Calif. 

Miles  Conrad 1224  Louisiana  Ave New  Orleans,  La. 

William  L.  Poser Box  708-B  Route  A__ Fresno,  Calif. 

Paul  Hayes 918  Bell  St Pasadena,  Calif. 

Eugene  Borsaltue 1518  Wash.  St ..Gary,  Ind. 

Sibley  Law Saxon  Mills Spartanburg,  S.  C. 

Archie  H.  Klingbeil 258  Prospect  St Ashtabula,  Ohio. 

S.  J.  Todd 1832  E.  82nd  St... Cleveland,  Ohio. 

Thomas  Burke. 3016  Warren  Ave Chicago,  111. 

J.  W.  Vine — Swallows,  Colo. 

William  Barker 571  Linwood  Ave Columbus,  Ohio. 

Hugh  Jones,  Jr 503  Horatio  St Tampa,  Fla. 

Harry  E.  Lake 1529  Stone  St .....Flint,  Mich. 

R.  J.  Dolan. .Nelson,  N.  B.,  Can. 

Maxwell  Krasno 1219  26th  St..... Milwaukee,  Wis. 

Arthur  Rabe. 21  Archer  Ave Buffalo,  N.  Y. 

M.  Watson 1925  Bigelow  St..... ....Cincinnati,  Ohio. 

Albert  M.  Turney,  Jr 3944  Massachusetts  St.. ..Long  Beach,  Calif. 

Wm.  Wreeland,  Jr. 67  Union  St ...Montclair,  N.  J. 

Hudson  Marhoff. 919  Lakeside  Place ...Chicago,  111. 

Jas.  Geyse- 1005  Swissvale  Ave Wilkinsburg,  Pa. 

G.  Titmarsh _. 120  Benson  Ave Toronto,  Ont.,  Can. 

C.  H.  Wendt 601  So.  50th  Ave Omaha,  Neb. 

Jack  Dobson,  Jr. Pineflat Sonoma,  Calif. 

H.  E.  Potter. 1  Hayden  St Binghamton,  N.  Y. 

William  Corcoran 26  Arlington  Ave__ Auburn,  N.  Y. 


with  DT  buttons  this  month  can  well  be 
proud. 

It  seems  that  more  and  more  of  the 
radio  fans  are  turning  to  the  loop  aerial 
as  the  only  means  of  satisfactory  re- 
ception. We  guess  that  we  are  right  in 
that  presumption,  as  the  "Strays" 
column  seems  to  bear  us  out. 

Keep  up  the  good  work  boys;  keep  it 
up. 

THE  PICK-UPS  EDITOR. 


RADIO  AGE: 

Enclosed  please  find  a  sketch  of  the 
radio  frequency  and  regenerative  outfit 
that  I  am  using  at  present,  and  from 
which  I  am  getting  very  good  results. 
With  a  small  thirty-foot  aerial  I  am  able 
to  pick  up  anything  east  of  the  Rocky 
Mountains.  I  use  about  twenty-five 
feet  for  real  DX  work,  as  I  find  that  this 
reduces  interference  to  a  minimum. 
Using  the  small  aerial,  I  am  able  to  tune 
from  200  to  560  meters,  and  while  the 


50 


RADIO  AGE  for  February,  1925 


Above  is  the  circuit  contributed  by  Mr.  McDonald,  showing  the  method  of  adding  radio 
frequency  to  a  regenerative  set. 


volume  is  not  quite  as  good  as  it  would  be 
with  the  larger  aerial,  the  selectivity 
more  than  makes  up  for  that  loss. 
•  For  the  radio  frequency  transformer  I 
use  a  low  loss  coil  of  the  type  that  is  com- 
monly used  in  neutrodyne  sets,  with  a 
.00035  Variable  condenser  across  the 
secondary.  A  three  circuit  tuner  is  used 
before  the  detector  tube,  and  the  secon- 
dary is  tuned  with  a  .0005  variable  con- 
denser. As  there  are  any  number  of 
three  circuit  tuners  on  the  market,  I 
will  not  go  into  detail  here  as  to  their 
construction. 

Using  this  circuit,  I  have  logged  on 
week  nights  (not  Monday)  coast  to  coast 
and  border  to  border  stations  in  less  than 
two  hours,  time. 

Very  truly  yours, 
Chicago,  111.  F.  McDONALD. 


Mr.  McDonald  has  done  considerable 
experimenting  with  radio  sets  and  if  he 
says  this  circuit  is  good,  he  really  should 
know.  Ifany  of  the  fans  want  informa- 
tion as  to  the  winding  of  the  three  circuit 
tuner,  it  can  be  obtained  from  an  article 
in  another  section  of  RADIO  AGE.  Any 
of    you    fellows    who    have    three-circuit 


turns  of  number  26  wire  wound  on  a  tube 
three  inches  in  diameter.  The  rotor  is 
wound  on  a  tube  slightly  smaller  in 
diameter  and  has  six  turns  on  both  sides 
of  the  shaft.  Use  the  same  size  wire  when 
winding  the  rotor. 

At  present  I  am  experimenting  in  the 
hopes  to  improve  the  tuner,  but  I  am 
afraid  that  I  can  not  do  much  in  this 
regard,  as  the  circuit  seems  to  be  about 
as  near  perfect  as  is  possible.  Last  week 
I  listened  to  PWX,  Havana,  Cuba,  for 
half  an  hour,  using  only  the  GROUND 
CONNECTION.  To  me  that  seems  like 
pretty  good  DX  work. 

Trusting  that  you  will  see  fit  to  publish 
this  letter,  and  wishing  you  a  Happy  and 
Prosperous  New  Year,  I  will  close. 
Yours  very  truly, 

GILBERT  SLATER, 
88  Linwood  Ave.,  Pawtucket,  R.  I. 


We  are  very  glad  to  hear  from  you 
again,  Gilbert,  and  it  gives  us  real  plea- 
sure to  publish  your  circuitinourcolumns. 
We  like  to  hear  from  fans  who  use  the  old 
head  once  in  a  while.  Most  of  the  radio 
tuners  and  desire  to  add  a  stage  of  radio  fan3  today  take  too  much  for  granted  and 
frequency  can  easily  do  so  by  employing     don't  experiment  like  the  "old  timers"  (?) 


this  hook-up. 


RADIO  AGE: 
Gentlemen: 

I  am  sending  you  this  letter  to  let  you 
know  that  I  received  my  DT  button  all 
right  and  that  I  am  mighty  proud  of  it. 
I  feel  real  chesty  as  I  walk  down  the 
street  with  that  little  thing  stuck  in  my 
lapel. 

When  I  got  home  the  other  night,  there 
was  a  letter  waiting  for  me  from  a  fan  in 
Chicago,  who  had  seen  mv  name  in  the 
Strays  column  of  RADIO  AGE  and 
wanted  information  regarding  the  circuit 
I  described.  I  will  answer  it  immediately 
and  give  him  all  the  necessary  informa- 
tion so  that  he  will  be  able  to  build  a  set 
that  will  work  just  as  well  as  mine. 

I  am  enclosing  a  wiring  diagram  and  a 
description  of  the  set,  and  if  you  have 
room  in  your  valuable  columns,  you  can 
print  it  if  you  see  fit. 

The  circuit  is  a  variation  of  Mr.  Rath- 
bun's  (the  blueprint  Editor)  with  an 
aerial  adapter.  It  sure  is  a  DX-erand  does 
not  radiate  to  any  great  extent.  I  am  not 
a  bit  backward  in  giving  Mr.  Rathbun 
credit  for  the  circuit,  as  all  I  did  was  add 
the  coupler,   which  consists  of  fifty-five 


did. 

Your  set  must  be  very  good  as  the  re- 
sults you  get  with  it  are  just  fine;  in  fact 


~)\ 


oooS 


The  Magazine  of  the  Hour 

they  seem  so  good  that  maybe  ye  editor 
will  make  himself  one  of  'em. 

As  Gilbert  is  good  enough  to  offer  his 
services  to  any  fan  who  writes  him,  you 
fans  should  see  that  he  gets  a  few  letters. 


We  have  a  very  interesting  account  of 
a  receiver  built  by  Ted  Gerill,  of  5327 
Pershing  Ave.,  St.  Louis,  Mo.,  on  which 
he  gets  excellent  results.  We  are  going 
to  pass  it  along  to  the  fans  who  feel  that 
they  would  like  to  experiment  with  a 
receiver  of  this  type.  Below  is  Ted's,  let- 
ter: 

RADIO  AGE: 
Gentlemen: 

As  per  your  request  in  the  January 
issue  of  RADIO  AGE,  I  am  enclosing 
hook-up  of  the  set  with  which  I  am  get- 
ting excellent  results.  I  use  two  199- 
type  tubes  (detector  and  one  step  of 
audio).  The  circuit  as  you  no  doubt  can 
see  is  the  well  known  single  circuit.  The 
condenser  and  coupler  are  shielded  with 
tin  foil  to  eliminate  body  capacity. 

The  aerial  is  about  sixty  feet  long, 
strung  between  two  poles  or  masts  about 
thirty  feet  high.  And  on  clear,  cold 
nights  I  get  very  good  results.  My  set 
with  the  exception  of  the  head-phones, 
tube  and  the  audio  transformer,  was 
made  entirely  by  myself. 

Any  of  the  fans  who  would  care  to  cor- 
respond with  me  regarding  this  type  of 
set  are  cordially  invited  to  do  so. 
Yours  radio  respectfully, 

TED  GERILL, 
5327  Pershing  Ave.,  St.  Louis,  Mo. 


/With  the  above  description  and  wiring 
diagram,  Ted  has  given  us  a  list  of  the 
stations  that  can  be  logged  by  himself  at 
almost  any  time.  For  the  sake  of  per- 
mitting some  of  our  readers  to  make 
comparisons  we  will  jot  down  a  few: 
KDKA,  KFKB,  KFKX,  KOA,  CNRW, 
KFI,  KNX,  KHJ,  KPO,  WBZ,  WCAL, 
WEAF,  WGY,  WCD,  and  last  but  by 
no  means  least,  2LO  of  London,  England. 
Ted  evidently  'is  the  type  of  fan  that  we 
spoke  of  in  a  preceding  paragraph;  a  real 
experimenter  who  makes  most  of  his  own 
equipment.  For  his  efforts  we  are  going 
to  take  the  liberty  of  admitting  him  to 
the  great  order  of  the  Dial  Twisters. 


Einar  _  A.  Hultman  of  Jamestown, 
N.  Y.,  gives  something  in  the  radio  fre- 
quency line,  at  which  he  is  quite  profi- 
cient.    We  are  reproducing  his  letter  and 


Tfr 


\ 


A 


n 


o 


B- 


o 

At 


M- 


6 

3+ 


This  hookup  was  contributed  by  Gilbert  Slater.      It  shows  how  to  add  an  antenna 
RAdTo^ACF    Rathbun'!>  ?in$le  ^be  lo6l?  set'  r?<?ently  published  in  blueprint  form  in 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


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52 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


One  stage  of  radio  frequency  and  detector  is  shown  in  this  wiring  diagram,  the  work 
of  Ted  Gerill,  who  gets  wonderful  results.  Write  him  about  it  and  he'll  furnish  further 
details. 


wiring  diagram  and  trust  that  any  of  the 
fans  who  are  having  trouble  with  a  circuit 
of  this  type  will  find  his  contribution  a 
help. 


RADIO  AGE: 

Gentlemen: 

Enclosed  is  a  list  of  the  stations  I  have 
received  on  my  set,  which  I  constructed 
myself.  It  employs  one  stage  of  radio 
frequency  amplification  and  I  am  getting 
wcnderful  results  with  it. 

The  R.  F.  Transformers  are  of  the  air 
core  type,  such  as  are  used  in  the  neutro- 
dyne  circuit,  and  the  secondary  is  tuned 
with  a  small  condenser.  The  circuit  is 
not  critical  and  the  condenser  settings 
will  always  be  the  same.  Any  one  desir- 
ing further  information  on  the  subject 
can  address  me  at  my  home  if  he  so  desires. 
Very  truly  yours, 
EINAR  A.  HULTMAN, 
97  Baker  St.,  Jamestown,  N.  Y. 


WEBN,  WSB,  WLS,  KYW,  KFKX, 
CKAC  and  plenty  of  others.  Any  of  you 
fellows  who  want  information  on  circuits 
of  this  type  are  requested  to  get  in  touch 
with  him.  With  a  list  like  that,  is  he 
entitled  to  a  DT  button,  fellows?  I'll 
say  so.     S^  here  goes. 


STRAYS 

Jack  Dc_son,  Jr.,  of  Pineflat,  Calif., 
reports  that  he  is  able  to  receive  over  500 
miles  on  his  crystal  set,  with  more  or  less 
regularity.  He  has,  besides  the  crystal 
set,  a  two  circuit  tuner  with  one  stage  of 
amplification,  on  which  he  has  received 
quite  a  few  of  the  east  coast  stations  and 
Havana,  Cuba,  PWX.  Most  of  his  suc- 
cess he  attributes  to  location,  but  then 
we  know  that  quite  a  little  of  it  goes  to 
construction. 


Some  of  the  stations  received  by  Mr. 
Hultman  speak  well  for  the  sensitiveness 
of    the    set:       WCAL,     WTAS,     WOS, 


It  must  be  an  ideal  place  for  reception, 
up  around  Toronto,  Canada,  judging  by 
the  way  the  DX  lists  read  from  that  part 
of  the  country.  We  just  have  another 
darb  from  G.  Titmarsh,  who  has  logged 
two    stations    in    California    (KGO    and 


KHJ)  in  one  evening,  and  held  them  for 
over  two  hours  each.  That  is  quite  a 
nice  record  for  some  other  DT  to  shoot 
at. 


We  have  a  communication  from  Paul 
Hayes,  918  Bell  St.,  Pasadena,  Calif., 
who  is  very  anxious  to  become  a  DT. 
The  list  he  submits  surely  will  allow  us 
ta  admit  him  to  the  order.  He  is  one  of 
those  fans  who  are  commonly  known  as 
"hams"  or  "brass  pounders,"  and  the 
number  of  6's  that  he  has  worked,  in 
Hawaii,  is  a  caution.  And  this  reminds 
us — what  has  become'  of  the  relay  boys 
who  sit  up  till  the  milk~man  comes  around 
and  the  commercial  operators  both  aship 
and  ashore  who  have  plenty  of  inter2sting 
things  to  report  in  these  columns? 
Let's  hear  from  some  of  you  once  in  a 
while. 


William  Vreeland,  Jr.,  reports  that  he 
received  2EH  Edinburgh,  Scotland,  dur- 
ing the  International  Test  Week,  and 
that  he  has  an  official  confirmation  from 
that  station.  He  uses  a  neutrodyne 
hook-up. 


A  letter  from  Hugh  Jones  of  Tampa, 
Fla.,  tells  us  about  the  interference  the 
fans  in  his  part  of  the  country  have  with 
the  ships  on  the  Gulf  of  Mexico.  Despite 
this  fact,  he  has  a  very  good  list  of  DX 
stations  and  we  certainly  are  going  to 
award  him  a  DT  button  for  his  per- 
severance in  "standing  by"  and  getting 
through. 

Here  is  a  record  for  some  of  the  one 
tube  fans  to  shoot  at.  William  Barker  of 
571  Linwood  Ave.,  Columbia,  Ohio,  has 
received  KHJ,  WDAF,  WHB,  WOS, 
KGO,  CFCA,  WOAK,  KYW  and  a 
"flock"  of  others.  Yes  sir,  he  gets  his 
DT   Button. 


If  Marion  S.  Corly  will  send  us  her  ad- 
dress we  will  send  her  a  DT  button,  as 
the  list  of  stations  she  submitted  entitles 
her  to  one,  but  since  she  failed  to  give 
her  address  we  are  unable  to  mail  it  out. 
Many  of  these  "lady  bugs"  could  give  us 


End  yourRadioTroubles  for 30c  in  Stamps 


We  have  laid  aside  a  limited  number  of  back  i    ;ues  of  RADIO  AGE  for  your  use 
these  issues.   Select  the  ones  you  want  and  enclose    '0c  in  stamps  for  each  desired, 
store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 

May,  1922 

— How  to  make  a  simple  Cryatai  Set  for  S6. 

September,  1922 

— How  to  make  a  Regenerative  Set  at  a  low  cost. 

October,  1922 

— How  to  make  a  Tube  Unit  for  S23  to  S37. 

— How  to  make  an  Audio  Frequency  Amplifying  Trans- 

former. 

November,  1922 

— Design  of  a  portable  short-wave  radio  wavemeter. 

May,  1923 

— How  to  make  a  portable  Reinartz  set  for  summer  use. 

June,  1923 

— How  to  build  the  new  Kaufman  receiver. 

1 — What  about  your  antenna? 

December,  1923 

—Bu0ding  the  Haynes  Receiver. 

— Combined  Amplifier  and  Loud  Speaker. 

— A  selective  Crystal  Receiver. 

January,  1924 

— -Tuning  Out  Interference — Wave  Traps — Eliminator! 

— Filters. 

— A  Junior  Super-Heterodyne. 

— Push-Pull  Amplifier. 

— Rosenbloom  Circuit. 

March,  1924 

— An  Eight-Tube  Super-Heterodyne. 

—A  simple,  low  loss  tuner. 

— A  Tuned  Radio  Frequency  Amplifier. 

— Simple  Reflex  Set. 

RADIO  AGE,  Inc. 


April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated). 
—A  Ten-Dollar  Receiver. 
— Anti-Body  Capacity  Hookups. 
— Reflexing  the  Three-Circuit  Tuner. 
— Index  and  first  two  installments  of  Radio  Age  Data 
Sheets. 

May,  1924 

— Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

—Important   Factora   in   Constructing   a   Super-Hetero- 
dyne. 
— A  Universal  Amplifier. 
— A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne, 
—Radio  Age  Data  Sheets. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 
— Operating  Detector  Tube  by  Grid  Bias. 
— A  Three-Tube  Wizard  Circuit. 
—Data  Sheets. 

August,  1924 

— Breaking  Into  Radio  Without  a  Diagram- 

— The  English  4-Element  Tube. 

■ — Filtered  Heterodyne  Audio  Stages, 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 


Below  are  listed  hookups  to  be  found  in 
The  supply  is  getting  low,  so  enrich  your 

September,  1924 

— How  Cireful  Mounting  Will  Improve  Reception. 
— One  Tuning  Control  for  Hair'B  Breadth  Selectivity. 
— Four  Pages  of  Real  Blueprints    of  a    New  Baby    Het- 
erodyne and  an  Aperiodic  Variometer  Set. 
—Data  Sheets. 

October,  1924 

— -An  Easily  Made  Super-Het. 
— Two  Radio  and  Two  Audio  for  Clear  Tone. 
— A  Simple  Regenerative  Set. 
— The  Ultradyne  for  Real  DX. 

— Real  Blueprints  of  a  3-Tube  Neutrodyne  and  a  Mid- 
get Reflex  Set. 

November,  1924 


December,  1924 

— Blueprints  of  a  New  8-Tube  Super- Heterodyne. 
— How  to  Make  a  Receiver  that  Minimizes  Static. 
—A  Trans- Atlantic  DX  Receiver. 

— How  to  Make  a  Home   Made  Battery  Charger   and  z 
Loud  Speaker  at  a  Small  Cost. 

January,  1925 

— A  Reflesed  Neutrodyne 
—A  Sis  Tube  Super-Het 
— An  Efficient  Portable  Set 
— A  Tuned  Plate  Regenerator 
— Making  a  Station- Finder 


500  N.  Dearborn  St.,  Chicago 


RADIO  AGE  for  February,  1925 


some  dandy  DX  lists  if  they  would  but 
take  a  few  minutes  and  drop  us  a  line. 
This  month  we  are  lucky;  we  have  two 
with  us. 
Gentlemen: 

I  have  built  many  sets  and  tried  many 
hookups,  having  success  with  them  all. 
The  only  hook-up  I  had  not  tried  was  the 
reflex.  Being  a  constant  reader  of  your 
magazine,  I  ran  across  your  single  control 
Midget  receiver.  I  built  this  set  and  of 
course  it  had  to  be  like  this;  it  would  not 
work. 

After  experimenting  night  after  night 
I  began  to  get  discouraged,  leaving  it  rest 
for  a  few  days.  I  tried  again,  but  to  no 
avail.  Finally  I  began  to  get  discouraged 
with  RADIO  AGE.  Knowing  I  must 
have  made  a  mistake,  I  looked  for 
that  issue,  only  to  find  that  I  had  lost  it. 
Finally,  deciding  to  give  it  up  as  a  bad 
job,   I   dismantled  the  set,   only  to   find 


Here  we  have  a  single  circuit  type  of 
receiver  as  used  by  Mr.  Hultman  in  his 
wonderful  B  X  work. 

that  the  cause  of  the  failure  was  due  to 
my  own  carelessness. 

In  soldering  the  condenser  terminals  a 
small  amount  of  the  rosin  (I  used  rosin 
core  solder)  had  flowed  between  the 
binding  post  on  the  condenser,  and  al- 
though the  joint  was  soldered  perfectly, 
the  rosin  acted  as  an  insulator  and  as  a 
result  there  was  no  electrical  connection. 

I  want  to  beg  vour  pardon  for  feeling 
as  I  did  toward  RADIO  AGE,  and  at  the 
same  time  ask  you  to  please  forward  to 
me  the  hook-up  of  the  Midget  reflex, 
which  I  am  sure  will  this  time  prove  a 
complete  success. 

Very  truly  3'ours, 
MRS.  STEPHEN  HERZOG, 
3831  Wilton  Ave.,  Chicago,  111. 

That's  an  interesting  letter  from  a  lady 
fan,  who  builds  her  own.  Isn't  that  the 
way  it  usually  turns  out?  Some  little 
thing  that  just  cannot  be  located,  puts 
the  whole  set  on  the  hummer.  Yes,  Airs. 
Herzog,  we'll  forgive  you,  we  know  just 
how  you  feel.  You  are  to  be  compli- 
mented on  your  willingness  to  admit  your 
mistake.  The  desired  hook-up  will  be  for- 
warded immediately.  Hope  you  have 
better  luck  this  time. 


We  have  received  another  letter  from 
H.  F.  Lovett,  who  was  made  a  DT  last 
month.  He  writes  a  very  humorous  let- 
ter, very  much  so,  and  lives  in  Halifax, 
N.  S.  Amongst  other  things  he  reports 
that  he  has  listened  to  complete  programs 
from  KFKX  three  nights  in  succession. 
That's  pretty  good  DX.  Same  to  you, 
Mr.  Lovett.  (Turn  the  page) 


The  Magazine  of  the  Hcrar 
— . 


53 


David 
Grimes' 
oice 


The  new  Grimes  3XP  In- 
verse Duplex  circuit  has 
established  a  new  standard 
for  reflex  circuits  and  inci- 
dentally for  radio  reception. 
In  developing  this  unusual 
receiver  David  Grimes 
tested  each  piece  of  appara- 
tus as  to  its  ability  to  func- 
tion properly.  It  is  signifi- 
cant that  he  chose 


ff*ei»$on 

Transforaiers 


It's  just  one  more  instance  of 
Jefferson  superiority  demonstra- 
ted by  comparison.  Jeffersons 
are  everything  that  the  radio 
transformer  should  be  to  make 
your  loud  speaker  a  true  musi- 
cal  instrument. 

David  Grimes  is  only  one  of 
many  radio  authorities  the  world 
over  who  realize  that  better 
results  are  reached  through 
Jefferson  performance. 

Built  by  a  concern  with  over  20 
year's  experience  in  the  manu- 
facture of  high  grade  trans- 
formers. Jefferson  Transform- 
ers meet  matched  construction 
specifications. 

Sold    through  leading  dealers 
and  distributors. 

Jefferson  Electric 
Mfg.  Co. 

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Manufacturers  of 


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Bell   Ringing  Trans- 
formers 
Sign     Lighting 

Automobile  Ignition 

Coils 
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Testing  I 

nstruments 

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Furnace 

and       Oil 

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er    Ignition 

Coil. 

S  ei\cl   for* 
these  hookups 


Included  among  the 
circuits  for  which  we 
will  send  you  complete 
working  drawings  are 
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verse Duplex,  The  Jef- 
ferson Baby  Grand  six 
tube  Superheterodyne 
and  the  Jefferson  eight 
tube  Superheterodyne. 
Any  of  these  will  be 
sent  upon  receipt  of 
five  cents  in  stamps 
to  cover  postage. 


*      Tested  and  Approved  by   RADIO  AGE     ^ 


54 


RADIO  AGE  for  February,  1925 


Tonal  Beauty  Lies  Deeper 
than  the  Ornish 

^T^EEPER  even  than  the  circuit  diagram— chiefly,  indeed,  in 
•*S  the  audio  transformer. 

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with  an  ordinary  tuner  and  loudspeaker,  has  received  the  plaudits 
of  musical  authorities  hitherto  skeptical  of  all  radio  reproduction. 
Perfect  amplification  makes  of  radio  a  joy  unending.  Who  shall 
say  that  such  a  benefit  is  not  worth  the  slight  additional  cost? 

There  is  romance  in  the  story  of  Rauland- 
Lyric.  A  request  will  bring  it  to  you 
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gvY-mTmyczEff; 


The  Magazine  of  the  Hour 

H.rR.  Pruitt  of  Fillmore,  Ind.,  has  sub- 
mitted a  very  interesting  account  of  a 
circuit  that  is  proving  quite  popular  in 
his  part  of  the  country.  It  seems  to  be  a 
variation  of  the  well  known  Autoplex. 
Sorry  that  we  haven't  room  to  print  it, 
but  he  says  he  will  answer  all  communi- 
cations that  are  addressed  to  him. 


R.  J.  Dolan,  of  Nelson,  N.  B.,  Canada, 
submits  a  list  of  stations  that  he  received 
on  his  single  tube  loop  set,  as  described 
by  our  Mr.  Rathbun  a  few  months  back, 
that  would  make  most  fans  turn  green 
with  envy.  Amongst  others  is  a  verified 
report  from  KGO,  over  3,000  miles  from 
his  city.  That  IS  real  DX  work.  Stick 
to  it  Mr.  Dolan;  stick  to  it. 


Tested  and  Approved  by  RADIO  AGE 


It  seems  that  this  past  month  was  quite 
a  good  one  for  the  single  tube  fan.  Harry 
E.  Lake  of  1529  Stone  St.,  Flint,  Mich., 
reports  receiving  Aberdeen,  Scotland, 
Madrid,  Spain,  Havana,  Cuba  and  a  flock 
of  distant  stations  on  a  single  circuit  out- 
fit, during  the  International  Test  Week. 

Archie  H.  Klingbeil,  258  Prospect 
Street,  Ashtabula,  Ohio,  hands  in  a  re- 
port of  stations  received  on  his  five  tube 
neutrodyne.  His  log  is  very  complete. 
Very  few  professional  operators  keep  a 
better  one.  You  have  the  right  idea, 
Archie;  that's  the  way  they  should  be 
kept. 

M.  Watson,  who  listens  in  from  1925 
Bigelow  St.,  Cincinnati,  Ohio,  has  a 
world  of  interesting  dope  for  the  crystal 
fans  if  they  will  but  write  him.  As  there 
has  been  more  or  less  interference  in  that 
city  until  recently,  when  the  transmitting 
bands  were  adjusted,  he  knows  of  -what  he 
speaks.  Sorry,  but  our  space  is  not  large 
enough  this  month  to  permit  us  to  pinit 
your  contribution. 

Ralph  Riley  of  Oakland,  Calif.,  writes 
to  let  us  know  what  good  results  he  is 
getting  from  his  first  set,  which  he  con- 
structed from  one  of  our  isometric  draw- 
ings. As  he  is  a  new  fan,  and  this  was 
his  first  set,  he  seems  to  be  considerably 
surprised  that  it  operates  correctly. 
That  just  proves  that  our  slogan,  "Let 
our  Hook-ups  be  your  guide,"  is  correct. 

James  Grindle  of  Hammond,  Ind.,  cer- 
tainly gets  a  DT  button  for  the  list  of 
stations  he  submits.  He  has  an  "ultra- 
dyne"  built  from  RADIO  AGE  instruc- 
tions and  he  certainly  is  getting  wonderful 
results  with  it.  All  his  stations  are  re- 
ceived on  a  36  inch  loop,  and  he  has 
logged  practically  every  station  in  North 
America  together  with  plenty  of  Euro- 
pean ones.  His  set  must  be  very  selec- 
tive, as  he  has  heard  amateurs  in  prac- 
tically every  district.  He  picked  up  six 
foreign  stations  during  the  International 
Test  Week,  and  has  certificates  of  veri- 
fication from  all  of  them  to  prove  re- 
ception. 

Any  of  our  readers  who  want  some  real 
information  regarding  the  Haynes  DX 
circuit  can  get  worth-while  information 
from  Roy  M.  Canfield  of  45  No.  Park 
Ave.,  East  Orange,  N.  J.  He  submitted 
a  very  interesting  article  regarding  this 
set's  construction  and  operation.  Per- 
haps we  can  publish  it  in  a  future  issue 
of  RADIO  AGE. 

E.  E.  Richmonds  of  Waynesville,  111., 
wants  to  hear  from  some  of  the  "Rein- 
artz"  fans,  whom  he  thinks  are  going 
back  on  the  old  circuit.  If  he  only  could 
see  our  mail,  I  know  he  would  think  dif- 
ferent. He  is  a  real  follower  of  John  L., 
and  his  letter  proves  that  he  has  done  con- 
siderable experimenting  with  this  circuit.1 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


55 


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*     Tested  and  Approved  by   RADIO   AGE     * 


56 


RADIO  AGE  for  February,  1925 


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Meet  Our  First  Radio  Mother 

( Continued  from  page  33) 

Stars  from  the  KYVV  studio  gave  the 
program  and  met  their  many  friends  in 
the    radio    audience. 

So  popular  was  the  first  tea  and  so 
crowded  for  the  children  that  Mrs. 
Peterson  promised  her  "radio  kiddies" 
that  she  would  have  a  special  Christmas 
party  for  them,  with  a  Christmas  tree 
and  gifts  for  all.  Again  every  available 
place  was  filled  with  radio  families. 
Children  were  perched  on  top  of  the  ice 
box,  on  the  stove  and  on  the  platform. 
When  Mrs.  Peterson  turned  Santa 
Claus  and  gave  them  a  gingerbread 
woman  cookie  which  she  had  made 
especially  for  them,  in  addition  to  a  box 
of  candy,  their  joy  was  unbounded. 

The  Children  All   Know  Her 

RECENTLY  the  phone  rang  just 
■  before  Mrs.  Peterson  was  to  broad- 
cast. "This  is  Dr.  Blank  talking.  I 
have  a  little  patient  who  has  been  very 
ill.  She  told  me  this  morning  when  I 
called  that  if  you  would  only  speak  to 
her  over  the  radio  it  would  make  her 
well  faster  than  any  of  my  medicine. 
Could  you  just  say,  'Good  morning, 
Peggy?" 

And  that  morning  over  the  air  Mrs. 
Peterson's  cheering  voice  said,  "Good 
morning,  Peggy.  You  are  better.  Call 
me  on  the  phone  when  you  are  able  to 
sit  up." 

A  Real  Cooking  Class  Over  the  Air 

A  course  in  general  cooking  in  a  series 
of  twelve  lessons,  covering  everything 
from  soup  to  desserts,  has  been  given 
twice.  Registrations  were  made  by  mail, 
with  the  understanding  that  to  each 
woman  reporting  that  she  had  tried  the 
recipes  from  nine  out  of  the  twelve  les- 
sons, a  certificate  would  be  issued.  If 
any  difficulties  arose  in  making  the 
recipe,  if  any  part  was  not  clear,  a  ques- 
tion by  mail  brought  a  prompt  answer, 
which  pointed  out  the  mistake  and  made 
success  assured. 

Several  thousand  women  registered 
for  these  courses  and  came  into  the  Home 
Service  Department  for  the  graduating 
exercises  at  the  end  of  the  course. 

Now  hundreds  of  women  are  asking  for 
an  advanced  cooking  class  by  radio,  and 
it  has  been  arranged  to  give  a  series  of 
twelve  lessons  in  January.  These  lessons 
are  based  on  Mrs.  Peterson's  new  radio 
cook    book,    "Simplified    Cooking." 

To  make  it  easy  to  jot  down  the 
recipes  and  keep  them  in  a  permanent 
book,  Mr.  Paul  D.  Warren,  Superin- 
tendent of  Home  Service,  has  prepared 
a  radio  recipe  note  book,  complete  with 
space  for  index,  in  addition  to  forty-eight 
blank  pages,  sent  free  to  all  radio  listeners 
in  Chicago,  and  available  to  all  others 
for  three  two  cent  stamps  to  cover  cost 
and  postage. 

"No  wonder  the  men  like  this  service," 
says  Mrs.  Peterson;  "it  is  headed  by  a 
man.  I  want  every  radio  pal  of  mine  to 
know  that  the  real  inspiration  of  this 
service  is  Mr.  Warren,  who  makes 
possible  the  carrying  out  of  all  our  most 
delightful  plans."  (Turn  to  page  57) 
¥     Tested  v-nd,  Approved  by  RADIO  AGE     H- 


The  Magazine  of  the  Hour 


-proving  the  need 
o^FIfcKO-LEAK 

SCIENTIFICALLY  correct! 

Here's  a  typical  "grid  log" 
which  shows  the  need  of  a 
variable  grid  leak.  A  Fil-Ko- 
Leak  was  substituted  for  a  1 
meg.  fixed  leak.  It  was  adjusted 
for  each  station  until  Volume 
was  greatest  and  distortion 
eliminated. 

Note:  Only  four  of  thirty- 
one  stations  came  in  with 
the  Fil-Ko-Leak  set  at  1 
megohm,  the  value  of  the 
leak  it  replaced. 

Megohms 

WFAA  Dallas,  Texas 5 

WMH    Cincinnati.  Ohio. ..2H 

WSB      Atlanta,  Ga 5 

WSH      Chicago,  111 ....2 

WGN     Chicago,  111 2 

*WSAI     Cincinnati,  Ohio.. .1 
WHB     Kansas  City,  Mo...lJ^ 
WLW     Cincinnati,  Ohio... 4 

KSD      St.  Louis,  Mo 4H 

WCBD  Zion  City,    II! 4  H 

WTAS   Elgin,  III. 3H 

WOC      Davenport,  Iowa . .  5 

KGO       Oakland,  Cal 5 

KFI  Los  Angeles,  Cal. . .  2  K 
WDAR  Philadelphia.  Pa... 134 
VVMAT  Dartmouth,  Mass.. 4 H 

*WBZ       Springfield,  Mass.  .  1 

WEAF  New  York 3 

WOO      Philadelphia,  Pa . .  .4 

$/%AA       WOR     Newark,  N.J 3M 
•lUU        WWJ      Detroit,  Mich 4 
»  w  w      *WTAM  Cleveland,  Ohio ...  1 
f                    WOS      Jefferson  City,  Mo.2 

^J  WTAY  Oak  Park,  111 H 

,~T      ,  KDKA  Pittsburgh,  Pa K 

In  Canada         KYW     Chicago,  III 3H 

$2.90  WDBH  Worcester,  Mass. . .  4  H 

KFNF    Shenandoah,  Iowa.  5 

WQJ       Chicago,  III 3H 

WDAF  Kansas  City,  Mo... 1 
WHK     Cleveland,  Ohio . . .  1  Y2 

Each 

FIL-KO-LEAK 
pr     is  Hand 
gS^  Calibrated 

S.an'aard   Jgjf  111    MeffohjTlS 

Condensers^*  ,^^_^___ 

— for  improved 
reception 

YOU  can  "log"  your  Fil-KO- 
Leak  just  as  you  do  your 
other  tuning  units.  You  will 
get  stations  you  never  heard 
before.  You  will  clear  up  dis- 
tortion on  nearby  broadcasters 
and  increase  volume  of  weak, 
distant  stations  and  get  them 
with  crystal  clarity.  You  read 
Fil-KO-Leak  resistance  in  exac* 
terms  of  the  megohm  through 
a  peep-hole  in  the  panel.  (It's 
also  equ  ipped  for  baseboard 
mounting).  Resistance  element 
is  constant  and  accurate,  and 
is  not  affected  by  atmospheric 
conditions,  wear  or  jarring. 
Every  Fil-KO-Leak  is  guaran- 
teed to  be  perfect  electrically 
and  mechanically,  and  to  be  " 
accurately  calibrated  over  the 
operating  range  for  all  tubes 
(^  to  5  megohms).  This  cali- 
bration is  doubly  checked. 
Literature  on  improved  recep- 
MmffVnFVnition  sent  on  receipt  of 2c  post- 
NS^MIf/>WZJse  to  Dept   RA  225. 

^?rVPkadio^>  MADE  AN° 

smarts!    gu™ed 

%        C/J^instrUmentcq) 

HARRISBURG,  PA. 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour  57 


To  offer  all  of  this  wonderful  service, 
Mrs.  Peterson  has  to  have  about  her  a 
staff  of  women  trained  in  Home  Econom- 
ics. Each  member  of  her  staff  is  a 
specialist  and  she  has  been  anxious  to 
have  her  radio  family  know  her  Home 
Service  family.  For  over  a  year  Miss 
Vivette  Gorman,  the  party  specialist, 
has  been  giving  Sunday  night  suppers, 
lunch  box  suggestions  and  novelties  for 
entertaining  over  the  radio.  Her  talks 
at  9:00  o'clock,  Wednesday  evenjng  from 
Station  K.Y.W.  have  solved  the  pro- 
blem for  many  a  hostess  in  distinctive 
entertaining. 

In  accordance  with  the  interest  shown 
by  the  radio  pals  in  knowing  the  other 
members  of  the  staff,  Mrs.  Peterson  has 
introduced  Miss  Grace  Wright  and 
Miss  Ruth  Yoe  for  a  series  of  weekly 
food  talks. 

"What  is  our  recompense  for  this 
wonderful  service?"  says  Mrs.  Peterson. 
"It  lies  in  knowing  that  all  over  this 
country  women  are  finding  cooking  a 
joy,  not  a  job,  and  that  they  tune  in  at 
11:35  each  morning  to  find  a  friend  who 
goes  into  the  kitchen  with  them.  The 
kitchen  is  the  heart  of  the  home. 
Through  it  we  truly  serve." 


Mandolinist  Deluxe 


Above  is  an  "action"  photo  of  Zyg- 
munt  Nowicki,  mandolinist  who  has 
appeared  recently  on  RADIO  AGE 
programs  from  the  Congress  Hotel  studio 
of  KYW,  Chicago.  Mr.  Nowicki  is 
connected  with  the  Polish  consulate  at 
Chicago  and  is  widely  known  for  his 
prowess  with  the  mandolin.  He  ap- 
peared for  RADIO  AGE'S  last  program 
on  January  3,  beginning  at  midnight,  and 
is  scheduled  to  be  on  the  air  for  this 
magazine  again  on  Saturday,  February 
7,  from  the  same  station  at  the  same 
hour. 


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Tested  and  Approved  by  RADIO  AGE     4 


The  Magazine  of  the  Hour 

Who's  the  Red-Headed  Girl 
from  WFAA? 

{Continued  from  page  35) 
"I  have  played  the  piano  since  I  was 
large  enough,"  she  continued.  "All  of  my 
playing  is  by  ear  and  I  have  always  picked 
Up  any  unusual  little  songs  that  struck 
me  as  unique  from  people  and  phono- 
graph records.  I  don't  care  much  for  the 
usual  popular  music.  I  do  sing  and  play 
some  of  it,  but  I  like  the  others  best. 

"My  pianologues  have  always  made 
a  hit  at  parties,  and  I  have  always  enjoyed 
doing  them.  Adam  Calhoun,  announcer 
for  WFAA,  heard  me  once  and  thereafter 
continually  begged  me  to  give  a  radio 
program,  which  I  positively  refused  to  do. 
"Not  that  I  didn't  want  to,  but  I  had 
no  idea  that  people  would  like  anything 
that  I  could  do.  One  day  Mr.  Calhoun 
came  up  and  asked  me  to  come  to  the 
studio  and  play  some  for  him  while  he 
made  a  few  tests  in  the  operating  room. 
Of  course,  I  didn't  mind  doing  that,  and 
I  don't  remember  anything  that  I  played 
and  sang,  but  without  my  knowledge  or 
consent,  that  was  my  debut  into  radio- 
land." 

Dear  reader,  have  you  ever  written  the 
"Red-Headed  Girl"  a  card  or  letter  of 
appreciation?  Yes?  Then  it  might  have 
been  you  who  first  informed  her  that  her 
voice  had  been  heard  outside  of  the 
studio. 

Don't  fail  to  give  Mr.  Calhoun  his 
share  of  the  credit  for  these  popular  con- 
certs, for  it  was  a  clever  ruse  that  he 
worked  to  get  her  before  Mr.  Mike. 

"Was  I  angry?  No,  I  was  flattered 
indeed  to  receive  mail  in  such  quantities," 
she  confided.  "I  enjoy  giving  my  pro- 
grams as  much  as  my  audience  does  hear- 
ng  them. 

She's  Modest,  Too 
"T  DON'T  sing;  I  don't  even  attempt 
•*•  to  sing,  and  about  the  hardest  blow  I 
have  ever  received  was  in  a  recent  letter 
asking  who  my  accompanist  was.  My 
playing  is  my  one  redeeming  feature  and 
my  singing  is  accidental.  Three  numbers 
that  never  fail  to  bring  applause  are 
"Baby  Vampire,"  "Please  Keep  Out  of 
My  Dreams"  and  "Broadway  Taxicab." 
These  unique  programs  have  brought 
her  invitations  from  many  towns  to  ap- 
pear in  person  but  only  one  has  been  ac- 
cepted, that  being  in  her  old  home  town, 
Greenville. 

"I  read  and  play  golf  but  I  have  more 
fun  reading  my  radio  mail  than  anything 
else.  I  get  letters  from  everywhere  and 
some  of  the  cleverest  poems  imaginable." 
Unlike  some  popular  artists,  the  "Red- 
Headed  Girl"  does  not  carelessly  file  her 
mail  in  the  waste  basket  without  reading 
it.  She  reads  it  all  and  thoroughly  en- 
joys it. 


Radio    Age's    Schedule    on    the    Air 

From  WEBH  (370)  Tuesday  evening, 
January  27,  9  to  10  p.  m. 

From  KYW,  Saturday,  February  7, 
midnight  to  2  a.  m.,  536  meters.  Jazz 
carnival. 

From  WTAY  (283)  Oak  Park,  111., 
technical  talks  every  Wednesday  evening 
at  9:45. 


RADIO  AGE  for  February.  1925 


Detroit  Attends  Opening 
ofWCX 

(Continued  from  page  37) 
force,  so  a  word  about  them  will  not  be 
inappropirate.  There  are  two  orchestras, 
and  a  symphony  trio.  The  orchestras 
are  dance  and  concert,  and  are  the 
only  Victor  Recording  orchestras  in 
Detroit.  C.  W.  Kirby,  director  of  WWJ, 
the  Detroit  News  station,  was  up  in  the 
studio  and  he  told  me  about  Jean's 
music  makers.  He  is  quite  proud  of 
them,  for  he  started  them  on  the  road 
to  fame  by  having  them  broadcast 
through  his  station.  Kirby  was  on 
hand  to  congratulate  his  competitors  on 
their  fine  station.  Most  readers  will 
remember  that  Kirby  is  one  of  the 
country's  hardest  fighters  against  women 
announcers,  but  I  am  sure  that  everybody 
would  be  as  thrilled  as  I  was  by  his  little 
wife's  graceful  Highland  twists  of  speech. 

The  job  of  getting  the  station  in 
broadcasting  order  is  a  tribute  to  the 
hard-working  Mr.  Tony,  who  is  director. 
I  had  come  up  there  in  the  morning  to 
get  the  invitation  and  I  saw  a  bare  room. 

"You're  not  going  to  broadcast  from 
here,  are  you?"  I  asked  in  amazement, 
for  completion  seemed  a  month  off, 
instead  of  a  bare  ten  hours. 

"Sure,"  replied  Tony;  and  sure  enough, 
it  was  all  ready  and  in  good  shape  that 
night. 

T^HE  station  broadcasts  on  500  watts, 
-*-  and  carries  much  farther  now  from 
its  high  position  than  it  did  from  the  old 
Detroit  Free  Press  building.  Since  the 
opening  night,  reports  of  reception  at 
distances  unapproachable  in  the  old 
days  have  been  reported.  Which  seems 
to  be  an  argument  for  tall  towers  and 
great  heights  for  all  stations  which  hope 
to  reach  out. 

WCX  was  opened  on  May  4,  1922, 
and  acquired  a  great  reputation  for  its 
"Red  Apple  Club"  and  church  services 
sent  from  the  Central  Methodist  Epis- 
copal church  in  Detroit.  These  were  so 
impressive  that  a  man  once  sent  in  a 
check  for  $500  in  appreciation  of  the 
services. 


The  Magazine  of  the  Hour  59 


Chas.  Freshman  Co.  Moves 

Demand  for  the  Freshman  Master- 
piece 5  tube  tuned  radio  frequency  re- 
ceiver, which  within  a  period  of  less  than 
six  months  has  assumed  world  wide 
proportions,  has  compelled  the  Chas. 
Freshman  Co.,  Inc.,  to  move  into  the 
brand  new  twelve  story  fire-proof  build- 
ing at  240-8  W.  40th  St.,  New  York, 
known  as  the  Freshman  Building. 

The  vastly  increased  space  and  every 
known  manufacturing  convenience  will 
enable  the  Freshman  Company  to  more 
than  double  the  productions  of  the  Mas- 
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parts. 

It  may  interest  those  persons  who  are 
interested  in  the  growth  of  radio  to  know 
that  this  company  started  in  business 
with  a  single  item — the  "Antenella" — 
a  light  socket  plug  that  eliminates  the 
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only  two  and  one-half  years  ago.  Grow- 
ing to  a  point  where  the  monthly  business 
is  over  J:he  million  dollar  mark  within 
this  period  speaks  highly  for  the  public 
interest  in  radio. 


3oo,ooo 
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already 
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too.  Two  ampere  size  (East 
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charges  overnight  while  you  sleep.  And 
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It  is  more  compact  than  ever.  It  has  a 
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isearch  has  made  a  good  product  better! 

Keep  your  batteries  charged  with  a 
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Tu  nga  r 

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Tungar — a   registered  trademark— is  found  only 
on   the  genuine.    Look  for  it  on    the    nameplate. 

Merchandise  Department 

General  Electric  Company? 

Bridgeport,  Conn. 


GENERAL  ELECTRIC 


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Radio  Age,  Inc., 

500  North  Dearborn  Street, 
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COUPON  ON  PAGE  80 


The  Magazine  of  the  Hour 

Pity  the  Poor  Radio 
"Outside  Man" 

{Continued  from  page  30) 
thing  to  say  a  certain  job  will  be  broad- 
cast, and  it  is  entirely  a  different  proposi- 
tion to  do  it.  For  that  reason  Westing- 
house  has  to  depend  upon  the  initiative, 
ingenuity  and  resourcefulness  of  its 
outside  man.  The  seeming  impossibili- 
ties and  the  heartbreaks  sometimes 
released  to  lessen  the  pressure  on  an 
overworked  and  overwrought  outside 
man,  are  all  unknown  to  the  radio  public. 
What  has  transpired  leading  up  to  the 
event  is  never  known  except  in  the  inner 
circle  of  operations  where  the  boys  can 
unburden  themselves  of  all  the  details. 

At  the  present  time  KYW  happens  to 
have  as  its  outside  man,  John  J.  Michaels, 
an  ex-seagoing  operator,  about  as  tall 
as  a  minute  but  imbued  with  plenty  of 
grit  and  radio  acumen.  How  he  came 
to  give  up  the  sea  life  is  a  mystery  even 
to  Michaels  himself,  for  he  is  of  the 
type  that  will  always  have  the  tang  of 
sea  air  no  matter  in  what  walk  of  life 
he  may  be  strolling. 

KYW  will  have  booked  a  job  at  the 
stockyards  in  which  it  is  planned  to 
pick  up  the  speech  of  some  notable  at  a 
meeting.  The  first  thing  Mike  hears  of 
it  is  a  little  written  slip  on  which  is 
given  the  location,  the  time,  the  date 
and  where  the  microphone  is  to  be 
located.  So  far,  so  good.  Mike  goes 
ahead,  assembling  a  coil  or  two  and 
three  wires,  the  first  for  telephonic 
communication,  and  the  second  for  a 
microphone  line.  Then  he  resurrects 
a  line  amplifier  from  the  stock  room, 
adds  to  this  an  eight  volt  storage  battery 
for  the  filaments,  and  four  blocks  of  45 
volt  B  batteries  for  the  plates  of  the 
amplifier  tubes.  Next,  he  corrals  a  couple 
of  microphones  and  a  stand  or  two. 
Some  of  the  plunder  he  loads  into  an 
army  case  and  the  rest  of  it  is  strapped  on 
the  outside.  Oh,  yes,  he  has  almost  for- 
gotten the  test  set  and  his  own  tool  kit. 

When  all  of  these  items  have  been 
run  to  earth,  Mike  lugs  them  to  the 
elevator  and  down  to  the  street  where 
he  charters  a  taxi.  Arrived  at  his 
destination,  he  finds  the  job  is  two  flights 
up  and  no  elevator. 

On  arrival  he  leaves  his  first  load  and 
goes  down  for  the  second,  mopping  his 
brow  and  wondering  how  the  weather  is 
off  Hatteras.  Finally,  after  a  struggle, 
he  gets  all  of  his  stuff  on  the  top  floor. 
Then  he  sets  out  to  search  for  the  master 
of  ceremonies  to  find  where  the  micro- 
phone can  be  placed  to  best  advantage, 
also  where  the  announcer  is  to  sit  so  a 
microphone  with  a  switching  arrange- 
ment can  be  installed  for  this  worthy. 
He  finds  the  thirty-second  under- 
secretary of  the  chairman  who  tells  him 
all  the  places  where  he  may  NOT  put 
the  microphone.  Appeals  to  reason 
are  of  no  avail,  so  Mike  goes  looking  for 
the  main  steer  who  can  say  yes  or  no. 
Sometimes  he  finds  him;  sometimes  not. 
Always  the  man  higher  up  is  easier  to 
approach  and  do  business  with  than 
the  many  small  caliber  minions  to  be 
encountered.  So  Mike  strings  his  lines, 
finds  a  place  in  which  to  operate  the  am- 
plifier, rings  into  the  station  on  the 
Edison  building  for  a  test,  and  all  is  well 
until   the   moment   of   broadcasting. 

Just  about  two  minutes  before  the 
program  is  to  go  on,  it  is  found  that  some 
enterprising  waiter  has  kicked  down  the 
microphone  line,  or  someone  has  cut  it 
because  it  does  not  harmonize  with  the 
color  scheme  for  the  evening.  Mike, 
cussing   inwardly,    but   outwardly    calm, 


¥     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


61 


restores  it  to  its  original  form,  and  the 
stunt  begins. 

After  the  event  is  over  Mike  loads  all 
his  "junk"  and  rushes  back  into  a  taxi 
and  returns  to  the  station  to  dispose  of 
them  and  seek  solace  in  sleep,  having 
nightmares  of  the  job  booked  on  the 
morrow. 

KYW  has  always  been  especially 
active  in  broadcasting  outside  jobs  that 
woulji  appeal  to  its  radio  public,  and  the 
outside  man  has  more  than  his  share  of 
the  work.  One  job  in  a  theater  nearly 
caused  Mike  to  lose  his  mind,  for  the 
management  absolutely  refused  to  allow 
the  microphones  to  be  seen  by  the 
audience.  Hence  they  were  hidden 
down  by  the  footlights  under  a  tin 
enclosure  wherethe  stamp  of  feet,  the  tinny 
reverberation  of  the  footlights  and  bak- 
ing from  powerful  lights  almost  ruined 
the    microphones  and   the   broadcasting. 

You  can  never  tell  where  you  are 
likely  to  find  the  outside  man.  One  day 
he  will  be  at  a  football  game;  the  next 
finds  him  crouched  in  the  organ  loft 
of  a  church  picking  up  music  and  dust. 
The  next  day  he  might  be  under  the  river 
in  the  tunnel  picking  up  whatevermight 
be  going  on.  If  tomorrow  Mike  is  told 
that  KYW  is  to  broadcast  the  blubber 
of  the  Eskimos,  he  will  merely  smile, 
pack  up  his  plunder  and  consult  a  time 
table  for  the  next  dog  train  from  Spits- 
bergen or  Sitka. 


How 


Young  Banks  Kennedy 
"Arranged  It" 

(Continued  from  page  38) 

BANKS'  musical  endeavor  is  by  no 
means  confined  to  "arranging"  one 
song.  He  is  the  proud  author  of  such 
songs  as  "Dream  Ships  that  Pass  In  the 
Night,"  "Crying  for  the  Moon,"  "Harold 
Teen,"  and  several  other  beautiful  as 
well  as  eccentric  pieces  that  have  won 
favor  both  with  the  radio  listeners  and 
theater  patrons  in  the  Middle  West. 

Banks  has  a  personality  in  the  radio 
studio  that  makes  him  well-liked  at  once. 
And,  strange  to  say,  this  personality 
emanates  from  the  radio  studio  and 
reaches  the  hearths  where  theloud  speaker 
sends  his  joyful  ditties  into  thousands 
of  homes.  As  Eddie  Borroff  of  KYW 
would  say,  "Banks  arranges  it  somehow." 
There  can  be  no  better  way  to  close 
this  article  than  to  recite  one  of  the 
thousands  of  "Arrange  it"  verses.  We 
repeat  the  following  because  it  pertains 
to  radio.  You'll  have  to  listen  in  to  get 
the  others.  We  hope,  anyway,  that  no 
matter  how  famous  Banks  gets,  that 
he'll  never  be  too  proud  to  write  a  few 
hundred  more  "If  I  Can  Arrange  It" 
verses.  Here  we  go: 
"I'm  going  to  buy  me  a  radio  set, 
If  I  can  Arrange  it; 

It's  going  to  be  the  best  made,  you  bet, 
If  I  can  A  rrange  it; 

It  must  get  London  and  Paris,  of  course — 
I  want  to  hear  the  Prince  fall  off  of  his 

horse — 
If  I  can  Arrange  it — 

Arrange  it,  somehow. 
CHORUS: 
"For  I'm  an  arranger, 
A  first  class  arranger, 
The  best  in  the  land,  can't  you  see? 
There's   hardly   a   thing   in    this   wide, 

wide  world, 
That  hasn't  been  arranged  by  me!" 


You  will  be 
satisfied  with  a 
"Pacentized"  set 


THE  man  who  uses  Pacent  Radio  Essentials  in 
building  his  set  has  the  assurance  that  he  is  using 
the  finest  parts  that  engineering  skill  and  trained  hands 
can  build. 

That  this  confidence  is  not  misplaced  is  shown  by  the 

fact  that  over  40  of  the  leading 

radio  set  manufacturers  use  one 

or  more  Pacent  Radio  Essentials 

for   standard   equipment.    This 

shows  the  leadership  that  Pacent 

has  attained  in  the  radio  parts 

industry. 


Select  the  parts  for  the  new  set 
you  contemplate  building  from 
the  list  given  opposite.  Get  them 
from  your  favorite  dealer — he 
carries  them  or  can  get  them 
for  you. 

PACENT  ELECTRIC  COMPANY 

Incorporated 

91  Seventh  Ave.,  New  York  City 

Washington      Minneapolis      Boston      San  Francisco 

Chicago     Birmingham     Philadelphia     St.  Louis 

Buffalo        Jacksonville        Detroit 


*      Pacent 

RADIO  ESSENTIALS 


PACENT 
Radio  Essential's 
Adapters 

Improved  Audioformer 
Autoplug 
Coil  Plug 

Coil  Plug  Receptacle 
Condensers,  Low  Loss 
Detector  Stand 
Duojack 
Duoplug 

Duo-Lateral  Coils 
Headsets,  Everytorie 
Jacks 
Jack  Set 
Radioloop 
Loop  Plug 
Loop  Jack 
Multijack 
Plugs 

Potentiometers 
Rheostats 

Resistors,  Laboratory 
Sockets 
Twinadapter,  etc.,  etc. 


$£ 


DONT    IMPROVISE  -  PACENTIZE" 


FRESHMAN  SUPERIOR 

Yoa  can  depend  upon  them  to 
remain  accurate  at  all   times 
Made  of   high   resistance   material   impreg- 
nated throughout   (not  coated  paper).  Un- 
affected   by    climatic    conditions.     Will    not 
deteriorate.    Clamped  between  solid  knurled 
ferrules    assuring    rigid    construction    and 
firm   contact   at  ail   times. 
At   your  dealer' a,   otherwise   send  purchase 
price   and   you    will    be   supplied   postpaid. 
Cba».  Freshman  Co.,  Inc.  240-248  W.  40th   SL, 
Freshman   Bldg.,    N.   Y. 


RADIO  AGE  ANNUAL  FOR 
1924— AT  SPECIAL  PRICE ! 

Clip  the  coupon  and  send  it 
with  50  cents,  and  the  RADIO 
AGE  ANNUAL  FOR  1924  will 
be  sent  you  by  return   mail. 


RADIO  AGE, 

500  N.  Dearborn  St.,  Chicago. 

Enclosed   is   50   cents,   for   which  [send   me    the 
RADIO  ACE  ANNUAL  (or  1924. 


*     Tested  and  Approved  by  RADIO  AGE     * 


62 


RADIO  AGE  for  February,  1925 


Silver-Matshallinc. 


RAD  IO 


*     TWO-TEN  and  TWO-ELEVEN 


Long  Wave  Transformers 


MATCHED    TESTED    CHARTED 


For  Those  Who  Build 
The  Best 

Type  TWO-TEN  and  TWO- 
ELEVEN  Long  Wave  Transformers 
are  the  same  as  those  used  in 
the  SILVER-MARSHALL  401 
Unit,  except  that  each  instrument 
is  now  housed  in  a  separate  alum- 
inum case  with  bakelite  top. 

All  curves  are  charted  under  the 
personal  supervision  of  McMurdo 
Silver,  Asso.  I.  R.  E.,  and  all 
measurements  made  with  a  vac- 
uum-tube volt-meter  and  laboratory 
amplification  measurement  equip- 
ment of  the  most  advanced  type. 

These  transformers  are  suitable 
for  use  with  any  tube  in  from  one 
to  four  stages,  and  are  supplied  in 
sets  of  two  or  three  TWO-TENS, 
and  one  TWO-ELEVEN,  each  with 
identical  peaks. 

TWO-TEN — iron-core  intermedi- 
ate transformer.  Passes  11  kilo- 
cycle band  without  distortion. 
Peaked  at  5,000  meters  approxi- 
mately. Provides  1  lA  to  2  J-2  times 
the  amplification  obtainable  with 
any  other  transformer. 

TWO-ELEVEN — sharply  tuned 
input  or  output  transformer.  Peaked 
at  approximately  5,000  meters. 
Price,  for  either  transformer,  $8.00. 


An  Individual  Curve  Sheet  Goes 
With  Each  Instrument 

Ask  any  radio  engineer  what  HE  thinks  of  a  long  wave 
transformer  and  he  will  say,  "Show  me  its  curve.  ' 
If  no  measurements  are  available  he  will  chart  its 
curve  and  judge  accordingly — because  the  CURVE 
TELLS  THE  STORY.  That  is  why  the  curve  of 
each  Type  TWO-TEN  and  TWO-ELEVEN  Long 
Wave  Transformer  is  plotted  in  the  SILVER-MAR- 
SHALL laboratory.  The  characteristic  curve  is  re- 
corded directly  upon  the  tag  that  accompanies  each 
instrument.  It  shows  the  peak,  the  side-band  passed, 
the  amplification  to  be  expected  in  any  circuit.  With 
this  definite  data  you  can  build  your  intermediate 
amplifier  with  complete  assurance  of  success.  With- 
out it,  you  build  by  guesswork.  Insist  upon  getting 
the  curve-sheet. 

The  Curve  Tells  the  Story 


FREQUENCY  IN    KILOCYCLES 


WAVE  LENGTH  IN   METERS 


Parts  for   the  Silver  Super 

Circulars  and  prices  on  parts  for  the  -Silver  Super  will  be  "sent  upon  request.  Mr. 
Silver's  own  book,  "The  Portable  Super-Heterodyne,"  should  be  owned  by  every- 
one who  means  to  buiicl  this  "Seveo-tube  Wonder  Set."     Price 50c 


SILVER-MARSHALL,  Inc. 

105  So.  Wabash  Ave.,  Dept.  A 
CHICAGO,  ILL. 


Eastern  Distributors 

TWENTIETH  CENTURY 

RADIO  CORP. 

102  Flatbush  Ave., 

Brooklyn,  New  York 


HUDSON-ROSS 

Sells  only  Guaranteed 
Radio  Apparatus. 

Send  for  discounts.  - 

123  W.Madison  St.  Chicago 


CABINETS 

If  you  are  interested  in  a 
radio  cabinet  in  which  is 
combined  both  beauty  and 
practicability,  just  write 

LAKESIDE  SUPPLY  C0.; 

Dept.  R 

73  West  Van   Buren    St. 

CHICAGO,  ILL. 

Telephone,  Harrison  3840 


Paul  Green,  the  super -het  expert,  will  have  another 
enlightening  and  instructive  article  in  March  RADIO  AGE. 

*     Tested  and  Approved  by  RADIO  AGE     * 


The  Magazine  of  the  Hour 
Is  There  a  Radio  Trust? 

(Continued  from  page  4.) 
The  proceedings  against  Radio  Corpora-"" 
tion  and  the  seven  other  respondents  are 
still  pending.  On  April  9,  1924,  Radio 
Corporation  filed  its  answer.  Radio  Cor- 
poration denied  the  jurisdiction  of  the 
Federal  Trade  Commission  to  issue  the 
order  quoted  or  to  conduct  the  proceedings* 

A  rare  bit  of  radio  information  is -pre1'-', 
sented  in  the  closing  paragraph  of  Radio 
Corporation's  answer.  It  appears  that 
Radio  Corporation  was  created;-  for 
"Patriotic  Service"  and  furthermore, 
that  if  it  had  not  been  for  Radio  Cor- 
poration, the  modern  art  of  radio  com- 
munication would  not  exist. 

The  full  paragraph  is  printed  as  follows: 
XXXIII.     Respondent  alleges  that 
it  was  created  in   order  to  carry  out 
the  expressed  desires  and  wishes  and 
at  the  instigation   of  officials,   officers 
and    servants    of    the    United    States; 
that  the  respondent   was  created  pri- 
marily with  a  motive  of  carrying  on  and 
it  has  since  carried  on  a  patt iotic service 
of   making   a   world-wide   communica- 
tion system  of  radio  in  which  the  most 
important  influence  rests  in  the  United 
States  of  America  and  with  American 
citizens;   that   certain   of  the  arts  and 
arrangements     (and    those    the     most 
important)  in  the  complaint,  complained 
of   were   taken    under   the   supervision 
of  officials,  officers  and  servants  of  the 
United     States;     that     the     acts     and 
arrangements   which   are   in   the  com- 
plaint complained  of  have  been  in  the 
public     interest     and     to     the     public 
benefit  and  have  been  entirely  reason- 
able  and  have  greatly  contributed  to 
the  rapid  growth  of  the  art  of   radio. 
Through    them    and    because    of    this 
respondent,   the   modern   art   of   radio 
communication  now  exists." 
How  this  "Patriotic  Service"  of  Radio 
Corporation    has    worked   out    in    actual 
practice     and     in     contact     with     other 
American     individuals     and     groups     of 
individuals,     not     so     fortunately    aided 
by    "officials,    officers    and    servants    of 
the    United    States"    will    be    shown    in 
later  articles.     Court  decisions  on  recent 
attempts  of  Radio  Corporation  to  enforce 
patent  restrictions  have  apparently  not 
taken  into  account  the  patriotic  import- 
ance of  Radio  Corporation. 


"Precision' '  Features  D.  X.  L.  : :  - 
Condensers 

One  of  the  newer  condensers  brought 
forth  this  season  is  the  D.  X.  L.  line  of 
Straight  Line  Low  Loss  Variable  Con- 
densers, manufactured  by  the  D.  X."  L: 
Radio  Corporation,  5769  Stanton  Avenue,  - 
Detroit,  Michigan.  While  there  are 
several  unusual  features  of  design,  the 
most  outstanding  point  is  the  precision 
of  construction. 

D.  X.  L.  engineers  have  designed  this 
type  of  condenser  so  that  power  losses 
are  actually  too  low  to  measure.  Realiz- 
ing that  absolute  precision  in  construction 
is  essential  to  the  maintenance  of  this 
standard,  the  highest  quality  of  materials 
has  been  specified  and  a  rigidly  inspected 
production  maintained.  In  the  construc- 
tion solid  brass  and  aluminum  of  the  best 
quality  are  used  together  with  a  minimum 
amount  of  hard  rubber  for  insulation. 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


63 


Reach 
Out 

with 


LOW  LOSS  (Practically  No  Loss) 
Straight  Line  Condenser 

New  Stations  -   Increased  Volume 
Sharper    Tuning 

Your  set — no  matter  how  sensitive — 
will  improve  with  D.  X.  L.  Condensers. 
There  is  practically  no  power  loss.  Mad- 
rid—London— reach  out  for  them.  D.  X. 
L.  Condensers,  precision  built,  get  the 
utmost  from  all  sets. 

D.  X.  L.  is  one  of  this  season's  achieve- 
ments— one  step  forward  toward  perfec- 
tion. D.  X.  L.  Condensers  range  from 
$4.00  to  $5.00  list. 

Ask  for  literature — you'll  be  interested 
in  the  D.  X.  L.  design. 

Set  Manufacturers 

Add  to  thft  quality  of  your  set.  D.  X.  L.  Con- 
densers will  increase  your  sal(*s  enormously. 
And  you  can  depend  on  the  satisfaction  of  the 
owners.      'Wire   for  prices  and   deliveries. 

Purchase  from  your  dealer  or  send  money 
order  to  factory. 

D.  X.  L.  RADIO  CORPORATION 
5765  Stanton  Ave.  Detroit,  Michigan 


Ask  Any 
Amateur 

And  he  will  tell  you 
that  the  "Jewell  Trio" 
of  instruments  for 
transmitting  sets  are 
accurate  and  depend- 
able— yes,  the  best 
made.  (Our  Nos.  54, 
64  and  74.) 

5  Send  for  our  Radio 
Instrument  Catalog 
No.  15-A. 

5  Buy  from  your 
dealer. 


Offices  in  Principal  Cities 

Jewell  Electrical  Instrument  Co* 

1650  Walnut  St.        -        Chicago 

"25  Years  Making  Qood  Instruments" 


How  the  "Girl  with  the  Summer  Resort  Name"  Bowled  Over  the  Sophisticated 

New  York  Radio  World— Read  about  Her  in  the  Feature 

Section  of  the  March  RADIO  AGE. 


KHJ 
Los  Angeles,   Cal. 

We  are  glad  to  confirm  your  report  of  recep 
tion  of  our  program. 

John  S.  Daggett, 
"Uncle  John," 
Mgr.,  Times  Radio  Staff. 


General  Electric 
Company 

Pacific  Coast  5555  E.  14th  St. 

Broadcasting  Station  Oakland,  Cal. 

KGO  Sept.  11,  1924. 

Mr.  T.  J.  Kennedy, 
1360  University  Ave.,  New  York,  N.  Y. 

We  are  glad  to  confirm  your  reception  of 
KGO  on  the  evening  of  Sept.  6  as  we  were 
broadcasting  the  opera  "Carmen." 

We  always  appreciate  hearing  from  our 
radio  listeners  and  hope  that  you  will  be 
able  to  pick  up  KGO  regularly. 
Yours  very  truly, 

Jennings  Pierce, 
Radio  Broadcasting  Pub.  Dept. 


DX  Fans!  Confirmations  Stop  All 
"Doubting  Thomases" 

Confirmations  of  Stations  Received  from 
New  York,  N.  Y.,  with 

KENNEDY  TUNER 

DX  Fans!  If  you  want  real  results,  get  a 
KENNEDY  TUNER  AND  HAVE  THE 
WHOLE  U.  S.  A.  AT  YOUR  FINGER  TIPS. 

Only  one  dial  to  get  stations  and  the  other  to  increase  or 
decrease  volume.  Kennedy  Tuner  is  used  in  place  of  vario- 
coupler,  variometer  and  honey  comb  coils,  saving  the  cost  of 
over  $9.00  worth  of  unnecessary  junk  that  is  in  most  receiv- 
ing sets,  and  no  dead  end  losses. 


Tuner 

Including  Globe 
Trotter  Diagram 


GUARANTEE: 

If  not  satisfied 
after  30  days,  we 
will  cheerfully 
return  your 
money. 


KFI 
Los  Angeles,  Cal. 

Thanks  for  your  letter  received.  YeB, 
"The  Minuet,"  by  Louis  Parker,  was  broadcast 
from  the  Anthony  station  during  the  late 
program. 

Yours,  Radio  KFI. 


General  Electric 

Company 

Pacific  Coast  5555  E.  14th  St. 

Broadcasting  Station  Oakland,  Cal. 

KGO  Sept.  4,  1924. 

Mr.  Vincent  T.  Kenney, 
124  W.  96th  St.,  New  York,  N.  Y. 

We  are  glad  to  confirm  your  reception  of 
our  late  program  from  the  Hotel  St.  Fran- 
cis on  the  morning  of  August  27th. 

We  are  always  glad  to  answer  any  ques- 
tions of  our  radio  friends  and  hope  you  write 
in  often  with  your  comments. 
Yours  very  truly, 

Jennings  Pierce, 
Radio  Broadcasting  Pub.  Dept. 


KLZ  Denver,  Colo. 

We  are  pleased  to  acknowledge  receipt  of 
your  report  of  reception  of  our  phone  station. 
We  have  placed  a  tack  in  our  map  for  you. 

Reynolds  Radio,  Inc. 


Send  for  Free  Diagram 


T.J. 


* 


2-LO,  London,  Eng. 


RADIO  GLOBE  TROTTER 


1360  University  Ave.,  New  York,  N.  Y. 


We  beg  to  acknowledge  your  reception  of  our 
program. 

Yours  faithfully  for  the 
British  Broadcasting  Co.,  Ltd., 
Jr.  Director,  London  Station,  C.  C.  H.  King 


f     Tested  and  Approved  by  RADIO  AGE     * 


64 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


o 


Designed  by  R. 
B.  Lacault.  B.  B. 
A.  M.  I.  R.  E.,  in- 
ventor of  the  fam- 
ous Ultradyne  cir- 
cuit. This  mono- 
gram  seal   (R.   B. 


Stop  fishing  for  your  favorite  station.  Select  the 
program  you  want — get  it  lightning-quick.  Re- 
place your  old  dials  with  ULTRA-VERNIER 
Tuning  Controls.  Then,  when  you  have  tuned 
in  a  delightful  station,  pencil-record  it  on  the 
dial.  Never  again  need  you  guess  or  fumble 
for  that  station,  or  bother  with  wave-lengths. 
Simply  turn  the  finder  to  your  pencilmark,  and 
you  hear  it! 

Should  you  move — or  a  station   discontinue  or 
wave-lengths  change — erase  the  marks,   leaving 
the  dial  beautifully  clean  and  new.     Thus,  you 
may  now  have  all  the  joy  of  radio,  with  none  of 
f   Lacault     the   discouragements.      Moreover,  the   ULTRA- 
VERNIER  is  a  single  vernier  tuning  control. 
At    your  dealer;  otherwise  send  purchase 
price  and  you   will  be  supplied  postpaid. 

T  UN  I NG       CONT  ROL 

PHENIX     RADIO       CORPORATION 

3-9  BEEKMAN  STREET 


$0.50 


At  your  dealers 

Ma  d  e  by  the 
HammarlundMfe. 
Co..  your  assur- 
ance of  quality 
and  dependability 
— produced  solely 
for  the  Phenix 
Radio  Corpora- 
tion. 


NEW   YORK    CITY 


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Best  for 
Reflex 

and  Crystal  Sets 

FRESHMAN 

J>ouble  Adjustable 
Crystal    Detector 

No  more  searching  for  the  sensitive  spot. 
— Merelv  turn  the  knob  as  you  would  a  dial. 
For  base  or  panel  -mount-' 
ing,  complete  w-tk  Fresh- 
man Super  -  Crystal 
At  your  dealer1-,  ollmrwue  send  parch"  »e  price 
sod  you  will  !»*•  supplied  puatpaid. 

<  HAS.    FRESHMAN   CO.,    Inc. 

Freshman    Bldg., 240-248    W.    40th    St. 

New  York 


$1.50 


* 


HERCULES 


Aerial  Mast 

All  Steel  Construction 


Painted  black  complete  with  galvanized 
steel  guy  wires  and  masthead  pulley.  20 
ft.  mast  $10.  40  ft.  mast  $25,  60  ft  mast 
$45.  We  pay  freight.  Ideal  for  receiving 
or  transmitting.  Greater  range.  More 
satisfactory  results.  Write  for  literature 
and   large 

FREE  BLUEPRINT 

S.    W.    HULL   &   CO..    Dept.    R3 
2048  E.  79th  St.  Cleveland,   Ohio 


Now  Ready— The  RADIO 
AGE  ANNUAL  for  1925— One 
dollar  a  copy.  Get  yours  Now. 

Tested  and  Approved  by  RADIO   AGE     * 


Converting  the  Single  Circuit 

(Continued  from  page  28) 

is  left  entirely  to  the  desire  of  the  reader. 
If  the  present  cabinet  is  large  enough  to 
accommodate  the  additional  apparatus, 
so  much  the  better.  By  all  means  use 
it,  as  this  will  preserve  the  symmetry  of 
the  design.  If,  however,  this  is  impossi- 
ble, it  can  be  installed  on  a  small  auxil- 
iary panel  and  mounted  close  to  the  re- 
ceiving set.  The  writer  found  it  is  quite 
satisfactory  to  mount  the  unit  on  a  small 
panel  and  fasten  it  by  means  of  a  long 
wood  screw  directly  to  the  top  of  the 
cabinet,  which  houses  the  receiver  proper. 

If  an  auxiliary  panel  is  used,  it  will  be 
well  for  the  builder  to  remember  to  keep 
the  four  connecting  wires  (indicated  by 
the  dotted  lines  in  Figure  4)  from  the 
unit  to  the  receiver  as  far  apart  as  possi- 
ble. 

When  mounting  on  top  of  the  receiver 
cabinet,  I  used  flexible  wire  in  making  the 
connections  from  the  unit  to  the  receiver, 
to  permit  the  lifting  of  the  cover.  If 
your  set  is  of  the  kind  described  and  has 
two  stages  of  audio  amplification,  it  can 
be  refiexed  with  the  same  ease  and  at  less 
expense.  It  is  not  advisable  to  attempt  to 
add  more  than  one  stage  of  amplification 
to  the  one  tube  reflex.  A  second  stage  is 
seldom  used,  nor  is  it  desirable. 

The  single  tube  will  operate  a  loud 
speaker  on  local  stations  satisfactorily, 
while  one  stage  of  audio  amplification 
will  give  tremendous  volume.  Audio 
amplification  is  added  in  the  usual  way, 
the  phone  leads  being  connected  to  the 
primary  of  the  transformer,  either  direct 
or  through  a  jack. 

Construction    Details 

'T'O  build  the  unit,  proceed  as  follows: 
-*-  Secure  a  piece  of  cardboard  tubing 
3"  in  diameter  and  wind  the  secondary 
of  the  transformer  which  consists  of  51 
turns  of  the  No.  22  DCC  wire.  The 
primary  is  wound  on  top  of  this  and  con- 
sists of  31  turns  of  the  same  size  wire, 
separated  from  the  secondary  by  a  layer 
of  paper  or  "empire"  cloth.  The  trans- 
former.can  be  mounted  either  on  the  back 
of  the  condenser  or  on  the  baseboard  of 
the  auxiliary  panel.  Any  of  our  readers 
who  do  not  care  to  wind  the  transformer 
themselves  can  substitute  one  of  the 
dependable  manufactured  coils  which 
are  designed  for  the  neutrodyne  circuit 
but  will  work  equally  well  in  this  unit. 

Any  good  audio  frequency  transformer 
can  be  used,  but  the  builder  is  cautioned 
in  selecting  this  piece  of  apparatus,  as 
by  actual  tests  the  audio  transformer 
has  been  found  to  be  at  fault  in  75  per 
cent  of  the  reflex  sets  that  fail  to  func- 
tion. 

The  crystal  detector  should  be  of  the 
fixed  type,  although  one  with  an  adjust- 
able cat-whisker  can  be  used,  but  the 
first  mentioned  is  by  far  the  most  satis- 
factory. It  is  a  more  sensitive  detector 
and  the  close,  fixed  adjustment  does  not 
permit  of  high  resistance  between  its 
terminals  and  excludes  the  possibility  of 
oscillations  and  squeals.  Crystal  detec- 
tors composed  of  two  minerals  are  also 


RADIO  AGE  for  February,  1925 


very  efficient,  those  using  "zincite"  and 
"bornite"  giving  the  best  results.  The 
rather  heavy  pressure  on  the  minerals 
prevents  the  adjustment  from  being 
disturbed  easily.  The  crystal  detector  is 
a  very  necessary  part  of  the  reflex,  and 
as  such  too  much  can  not  be  said  regard- 
ing the  selection  and  operation  of  this 
piece  of  equipment. 

As  a  reflex  circuit  is  largely  a  radio 
frequency  one,  a  few  words  regarding  the 
kind  of  tube  to  be  used  might  not  be 
amiss.  Soft  tubes  such  as  the  UV  200, 
or  C  -300  cannot  be  used;  neither  can 
one  get  results  with  the  WD  11  or 
WD  12  tubes.  A  hard  tube  such  as  the 
UV201-A,  C  301-A,  UV  199  or  C  299 
will  give  excellent  results. 


The  Magazine  of  the  Hoi 


65 


Eight  Million  Hear  John 
McCormack 


New  York. — The  golden  tenor  of  John 
McCormack  and  the  lyric  soprano  of 
Lucrezia  Bori,  borne  through  the  air  to 
an  audience  of  at  least  8,000,000  persons, 
on  New  Year's  Night  ushered  in  a  new 
era  of  radio  broadcasting  and  raised  the 
question  whether  there  will  have  to  be  a 
realignment  of  the  economic  forces  which 
compete  in  entertaining  the  public. 

Radio  has  never  before  been  able  to 
draw  upon  the  talent  of  the  world's 
greatest  singers  and  musicians.  Mc- 
Cormack was  one  of  many  who  repeatedly 
declined  to  sing  for  it. 

However,  he  and  Bori  stepped  over  the 
barrier  and  from  a  little  room  at  WEAF, 
began  the  experiment  which  may  result 
in  amusement  and  entertainment  changes 
measured  by  millions  of  dollars. 

Linked  with  Many  Stations 

WEAF  was  linked  up  for  this  program 


SUPER-HETERODYNE 

Ultradyne— Haynu  Griffin— Rentier 
Dealers:    Send  for  Discounts 

HUDSON-ROSS 

123  W.  Madison  St.  Chicago 


Interior  stew  of  a 
typical  set  you  can 
build  with  the  new 
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You  can' t  buy  it 


but  if  you  are  the  least  bit 
handy  with  tools,  you  can  build 
this  amazing  Telos  set  your- 
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The  basic  goodness  of 
Telos  design  is  the  same 
as  it  has  been  for  three 
years.  But  now,  Telos  ex- 
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to  include  three  stages  of 
tuned  R.  F.  and  super- 
imposed (reflex)  resistance 
coupled  A.  F.  as  well. 

The  new  Telos  KIT  opens 
up  a  world  of  fascinating 
possibilities  in  radio.  As 
in  the  photo  above,  you 
can  build  a  5,  6  or  7  tube 
set,  and  run  it  all  on  dry 
cells.  It  will  cost  you  less 
to  run  than  any  other  set 
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You  can  introduce  a  crys- 
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you  can  use   transformer 


A.  F.  if  you  prefer.  But 
no  matter  what  combina- 
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Fill  out  the  coupon  now. 
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Thousand  Possibilities." 
It's  free,  but  the  edition 
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Send  me  at  once  your  booklet  "The 

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Ne 


Address . 


r* 


*     Tested  and  Approved  by  RADIO  AGE     * 


66 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


Amazing  Results 

WITH  THE  MUSSELMAN 

INSIDE   ANTENNA 

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what  atmospheric  conditions  prevail?  Then  you 
should  have  a  MUSSELMAN  INSIDE  ANTENNA 
— the  newest  sensation  in  radio. 

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Study  the  small  cut 
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MAN INSIDE  AN- 
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core;  then  1-32  inch 
rubber  insulation;  over 
this  an  outer  braiding 
of  tinned  copper  wire. 
The  latter  acts  as  an 
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WIRE  FOR  EVERY  RADIO  USE 
We  manufacture  all  kinds  of  insulated  radio  wire, 
including  colored  rubber-covered  hook-up  wire, 
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and  we  will  send  samples,  prices.  Tell  us  your 
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Name 

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AMERICAN  BRAND 
CONDENSER: 

v   tn*     VERNIER 

~  PLATE   $E<K> 
only  { 

Zor  Sale 
everywhere 

h  '  ■ :  * 

AMERICAN  BRAND  CORPORATION' 

8  WEST  PARK  ST.  NEWARK.  N.  J.. 


with  WCAP  Washington,  WJAR  Provi- 
dence, WNAC  Boston,  WDBY  Wor- 
cester, WGR  Buffalo,  WFI  Philadelphia, 
and  WCAE  Pittsburgh.  Thus  McCor- 
mack  and  Bori  reached  an  audience  a 
thousand  times  larger  than  either  had 
ever  entertained  at  one  time  before. 

What  will  happen  next  is  already 
worrying  many  of  those  who  are  in  the 
business  of  selling  entertainment  of  one 
kind  or  another. 

When  the  public,  sitting  comfortably 
at  home,  can  have  entertainment  of  the 
highest  caliber  without  direct  ex- 
pense, will  it  go  miles  away  and  attend 
the  theatre  at  a  cost  of  $2.75  and  upward 
for  each  seat? 

Will  it  buy  more  phonograph  records 
or   fewer   records? 

Will  the  thousands  of  persons  who  have 
hitherto  managed  to  resist  the  lure  of  the 
radio  capitulate  now  and  overwhelm 
manufacturers  and  dealers  with  orders 
for  receiving  sets? 

These  questions  are  going  to  be  an- 
swered very  quickly  for  the  Victor 
Talking  Machine  company  in  co-opera- 
tion with  the  American  Telephone  and 
Telegraph  company,  will  broadcast  two 
programs  of  similar  high  class  character 
each  week.  The  company  declares  the 
continuance  of  the  programs  "will  depend 
upon  the  response  we  receive  from  radio 
audiences." 

See  Menace  to  Theatre 

Theatrical  men  declared  tonight  that 
the  patronage  of  nearly  every  theater  in 
New  York  City  was  affected  by  the  ap- 
pearance of  McCormack  and  Miss  Bori 
as  radio  broadcasters.  Although  the 
theaters  invariably  suffer  a  falling  off  on 
the  evenings  following  holidays,  the  extent 
of  tonight's  decrease  was  that  it  could 
not  possibly  be  explained  by  that  rule 
and  theatrical  men  were  unanimous  in 
their  conviction  that  radio  was  largely 
responsible. 

"Radio  constitutes  the  greatest  menace 
that  the  theater  has  ever  faced,"  William 
A.  Brady  said.  "Why  in  the  world  should 
people  go  to  the  theater  and  pay  money? 
Why  should  any  one  be  foolish  enough  to 
go  to  the  theater  in  these  circumstances?" 

New  Fada  Chicago  Office 

Announcement  is  made  of  the  opening 
of  a  Fada  office  at  326  West  Madison 
Street,  Chicago,  Illinois.  This  Chicago 
Fada  office  will  be  in  direct  charge  of 
L.  J.  Chatten,  who  has  for  the  past  year 
and  a  half  been  a  district  sales  executive 
of  the  Fada  organization. 

Mr.  Chatten's  sales  work  in  the  past 
has  made  him  well  acquainted  with  radio 
sales  conditions  throughout  the  country 
and  in  particular  with  those  trade  con- 
ditions existing  in  the  Mississippi  Valley 
and  it  is  felt  that  his  qualifications  are 
admirably  adapted  for  the  position  of 
manager  of  our  Chicago  office. 

Mr.  Chatten  will,  of  course,  make  his 
headquarters  at  the  Chicago  office  and 
will  in  addition  keep  in  direct  contact 
with  Fada  jobbers  and  dealers  through- 
out all  the  Central  Western  states. 


ANNUALS  FOR  1924 
Only  a  few  left.      You  may  have 
one  by  sending  50  cents  to   Radio 
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RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


67 


The  How  and  Why  of 
Vacuum  Tubes 

(Continued  from  page  22) 
caused  the  plate  to  attract  the  neg- 
ative electrons,  thereby  establishing  a 
path  of  conductivity  between  the  plate 
and  the  filament,  but  when  the  negative 
terminal  of  the  battery  was  connected 
to  the  plate,  the  electrons  were  repelled 
from  it  and  no  conductive  path  was 
established  between  the  two.  For  this 
reason,  current  will  flow  only  in  one 
direction  through  the  tube,  and  when  an 
alternating  current  is  applied  to  the 
circuit,  those  impulses  which  flow  toward 
the  plate  only  will  pass  through,  while 
those  in  the  opposite  direction  cannot 
pass.  Thus  only  one-half  of  any  cycle 
will  flow  and  the  resultant  action  is  a 
pulsating  current  in  one  direction,  al- 
though the  applied  current  was  alter- 
nating. 

This  rectifying  quality  of  the  tube  made 
it  possible  to  use  it  as  a  detector,  in  much 
the  same  way  as  a  crystal  was  used,  only 
in  the  case  of  the  tube  it  was  necessary 
to  use  a  battery  to  give  the  plate  a 
positive  charge  to  attract  the  electrons. 

How  Current  Varies 

TF  A  pair  of  phones  is  introduced  into 
■  -*•  the  plate  circuit,  a  continuous  current 
will  flow  through  them  all  the  time  that 
-the  filament  is  heated,  but  the  changes 
.caused  by  an  incoming  wave  will  vary 
this  battery  current,  adding  to  it  when 
it  is  in  the  right  direction  and  weakening 
it  when  it  is  in  the  opposite  direction, 
:and  it  is  these  changes  and  not  the  con- 
tinual steady  flow  of  the  battery  current 
through  the  phones  which  cause  the 
(diaphragm  to  vibrate  and  give  off  a 
isound. 

In  the  crystal  detector,  however,  no 
current  flows,  except  that  of  the  signal 
■itself.  Thus  it  is  seen  that  the  rectifying 
^action  of  the  plate  and  filament  com- 
Ibination  will  make  a  fair  detector  of 
:radio  signals.  The  introduction  of  the 
third  element  into  the  tube  (the  grid) 
made  it  possible  to  obtain  a  relay  or 
amplifying  property  which  was  not 
apparent  in  the  two  element  tube.  This 
grid,  which  consisted  of  a  wire  mesh 
placed  between  the  filament  and  the 
plate,  really  ■  made  the  vacuum  tube 
popular.  With  this  three  element  tube, 
the  circuit  is  so  arranged  that  the  in- 
coming signal  is  impressed  upon  the 
grid.  The  battery,  plate  and  phones  are 
connected  in  series  and  as  long  as  the 
grid  is  not  electrically  charged,  a  con- 
tinuous current  flows  through  the  plate 
circuit  when  the  filament  is  heated.  The 
electrons  frooi  tne  filament  thread  their 
way  theougrKthe  wire  mesh  of  the  grid 
and  reach  the  plate  as  before,  but  if  a 
weak  charge  is  given  to  the  grid,  the  flow 
of  current  in  the  plate  circuit  will  be 
greatly  affected  by  it. 

In  the  up-to-date  circuit  of  today,  the 
return  of  the  grid  circuit  of  the  detector 
tube  is  connected  to  the  positive  side  of 
the  filament  battery,  and  a  grid  leak 
and  condenser  are  inserted  in  the  grid 
circuit.  This  keeps  a  slight  positive 
charge  on  the  grid,  which  tends  to  help 
the  plate  draw  the  electrons  out  of  the 
filament.    Because  of  this  positive  charge, 


ANsmAB 


*"Z)6>veIopect  /by-  EavlEinsiqvt 


The  Ensign  is  a  real  sliding,  square  plate  condenser  with  a 
straight  line  wavelength  graph,  using  the  entire  dial.  Sturdy 
construction.     One  hole  mounting. 


ARMOUR  INSTITUTE 
TESTS  SHOW 

Maximum  capacity 000521 

Minimum  capacity 0000087 

The  loss  was  so  low  the  labor- 
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it. 


PRICES 
Including  360  deg.  dial 

.00025 $4.50 

.00035 _ 4.75 

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Below  U  a  cut  of  bottom  of  condenser.  Note  the  intersecting  ai 
a  square.  The  size  of  this  square  changes  in  exact  geometrical  ratic 
slides  in  and  out  thus  spacing  the  wavelength  graduations  evenly  < 


i  between  plates  is  always 
s  the  movable  set  of  plates 
■r  the  entire  dial. 


Send  for  descriptive  literature.     Orders  filled  by  mail  until  dealers  are  established. 


WptnxfacturecX  by  CARLiETON  SANDERS  WshatvafajM. 


Look  at  these  writers! 
They  all  have  surprises  for 
you  in  the  March  RADIO 
AGE,  on  the  stands  Feb- 
ruary 15: 

Arthur  B.  McCullah 
Paul  Green 
Brainard  Foote 
Frank  D.   Pearne 
Edmund  H.  Eitel 
Zeh  Bouck 
John  B.  Rathbun 
H.  Frank  Hopkins 

And  an  up-to-the-minute 
section  about  your  radio  favor- 
ites.    Get  the 

MARCH  RADIO  AGE 


Wr 


NOTICE  TO  READERS 

TE  receive  many  remittances 
from  fans  who  want  us  to 
furnish  them  with  blueprints 
or  panel  layouts.  As  it  would 
be  practically  impossible  for  us 
to  stock  complete  blueprints, 
panel  layouts,  etc.,  of  all  cir- 
cuits, we  cannot  comply  with 
these  requests. 

However,  we  do  sell  BACK 
COPIES  of  RADIO  AGE,  and  if 
you  want  complete,  concise  in- 
formation regarding  construc- 
tion or  wiring  of  any  particular 
circuit,  we  should  suggest  that 
you  consult  the  list  of  back 
issues,  which  you  will  find  pub- 
lished in  RADIO  AGE  every 
month. 


*     Tested  and  Approved  by  RADIO  AGE     * 


68 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


TUNE  RIGHT  THRU  INTERFERENCE 
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A  tuned  radio  frequency  receiver 
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direct  to  us.     The  Service  Lamp  Co. 


{Continued  from  preceding  page) 
some  of  the  electrons  will  attach  them- 
selves to  the  grid  as  they  swarm  through 
it,    but   the    actual    result    is   a    greater 
.flow  of  electrons  to  the  plate. 

Now,  if  a  signal  is  received  on  the  grid, 
the  potential  of  the  grid  rapidly  alter- 
nates, because  the  current  is  alternating 
in  nature.  As  it  gets  a  positive  charge, 
some  of  the  electrons  are  attracted  to 
it  from  the  great  mass  which  is  passing 
through  to  the  plate. 

At  the  next  half  of  the  cycle,  the  grid 
becomes  negative,  but  the  electrons  are 
not  so  easily  thrown  off  from  a  cold  metal 
and  most  of  them  remain  attached  to  it. 
The  next  half  cycle  is  positive  again  and 
more  electrons  are  captured  by  the  grid. 
The  grid  becomes  more  and  more  negative 
the  longer  the  signal  lasts  until  it  reaches 
the  point  of  saturation.  At  least,  this  is 
what  would  happen  were  it  not  for  the 
high  resistance  grid  leak  which  allows 
them  to  leak  off  back  to  the  positive 
side  of  the  filament  battery.  They  can- 
not be  thrown  off  from  the  cold  grid  as 
they  are  from  the  filament;  consequently 
they  must  be  supplied  with  some  other 
means  of  escape  when  they  accumulate  to 
such  a  degree  that  they  would  clog  the 
action  of  the  tube. 

By  carefully  adjusting  the  resistance  of 
this  leak,  the  grid  can  hold  only  a  certain 
number  of  electrons,  and  it  is  this  adjust- 
ment of  resistance  which  is  so  vital  to  the 
efficient  operation  of  the  tube. 

The  more  negative  the  grid  becomes, 
the  greater  will  be  the  reduction  in  the 
current  flowing  in  the  plate  circuit,  and 
therefore  the  greater  the  changes  in  the 
current  flowing  through  the  phones,  which 
will  cause  a  louder  signal,  for  it  is  the 
change  in  this  current  which  affects 
the  phones  and  not  the  continuous  cur- 
rent which  flows  through  them. 

This  shows,  then,  how  the  tube  may  be 
used  as  a  detector  and  an  amplifier  at  the 
same  time, the  detecting  component  being 
caused  by  the  rectifying  qualities  and 
the  amplifying  being  caused  by  the  weak 
impulses  on  the  grid,  causing  enormous 
changes  in  the  plate  current. 

This  action  of  the  grid  is  sometimes 
called  the  trigger  action,  as  a  variation  of 
one  volt  on  the  grid  will  sometimes  produce 
a  hundred  times  as  much  change  in  the 
plate  current,  as  would  a  change  of  the 
same  value  in  the  plate  voltage.  When 
these  tubes  are  used  as  amplifiers,  the 
grid  is  kept  at  a  negative  potential  at  all 
times. 

Silver  Contacts  in  New  Socket 

One  of  the  unusual  features  of  the  No 
Loss  Isolantite  Socket  is  the  extra  large 
5-16  in.  in  diameter  sterling  silver  con- 
tacts arranged  so  as  to  be  self  wiping. 
The  contacts  are  fixed  to  heavy  phosphor 
bronze  springs  insuring  a  firm,  low- 
resistance  connection  at  all  times.  The 
spring  members  are  each  made  of  two 
leaves  and  they  are  placed  in  the  base 
in  a  way  to  minimize  internal  capacity. 
Permanent  soldered  connections  are  made 
to  main  phosphor  bronze  spring,  at  the 
same  time  serving  as  a  lug;  or  temporary 
connections  may  be  made  to  nuts  pro- 
vided for  this  purpose. 

The  base  of  the  socket  is  produced 
from  Isolantite,  which  has  been  found 
to  have  very  desirable  properties  for 
radio    use. 


¥     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


69 


Don't  Worry  About  that 
Antenna,  Fans 

{Continued  from  page  20.) 

you  get  louder  results,  more  distant 
stations,  more  atmospheric  disturbance 
and  more  interference  from  stations. 
Interference,  he  says,  is  the  real  limit 
on  receiving  distance.  Except  for  inter- 
ference, there  is  no  limit.  So  those 
fellows  who  listen  for  Mars  are  not  so 
crazy  after  all!  If  you  want  to  astonish 
your  friends,  says  the  doctor,  use  a  whale 
of  a  long  antenna,  or  use  a  very  sensitive, 
many-tube  receiving  set,  or  both,  and 
pile  up  your  records.  But  that  is  all 
you  will  accomplish,  he  adds.  You  will 
get  only  truly  satisfactory  reception 
during  the  exceptional  occasions  when 
interference  is  small.  Antenna  length 
is  a  compromise  between  loudness  of 
signals  and  freedom  from  interference, 
a  compromise  between  quantity  and 
that  perfection  of  quality  that  would 
be  ideal.  The  hysteria  over  distance 
records  is   diminishing. 

Indoor  antennas,  said  Dr.  Dellinger, 
violate  all  the  things  he  said  about  out- 
door antennas.  They  are  not  high  or 
long  and  they  are  close  to  parts  of  build- 
ings. The  best  form  is  50  or  more  feet 
of  copper  wire  suspended  on  insulators 
just  under  the  roof  and  extending  through 
an  insulating  tube  down  into  the  room 
where  the  receiving  set  is  used.  It  will 
work  almost  as  well  without  the  in- 
sulators. You  can  just  hang  the  wire 
around  the  moulding  of  your  room.  In 
fact,  you  can  connect  your  receiving 
set  to  the  bed  spring  or  to  the  wires  in 
your  piano,  but  the  results  will  be  less 
satisfactory.  With  a  special  plug  you 
can  connect  with  the  electric  wiring  of 
the  house  and  use  it  for  an  antenna,  if 
the  wiring  is  of  the  open  type.  Electron 
tube  sets  work  very  well  with  indoor 
antennas  because  they  are  readily  ad- 
justed to  make  up  for  the  lack  of  strength 
of  the  smaller  antennas.  A  crystal  set 
does  not  give  satisfactory  results  on  a 
short  or  indoor  antenna  except  for  rela- 
tively near  or  exceptionally  powerful 
broadcasting    stations. 

The  users  of  crystal  sets  no  doubt 
will  welcome  the  increased  power  to  be 
used  by  several  broadcasting  stations. 
Indoor  antennas  work  better  in  the 
upper  than  in  the  lower  floors  of  a  build- 
ing. The  smaller  and  lower  they  are, 
the  more  sensitive  must  be  the  receiving 
set  to  make  up  for  their  weakness,  but 
the  more  free  they  will  be  from  inter- 
ference. 

The  coil  antenna,  or  loop,  will  operate 
only  on  sets  particularly  designed  for  it, 
says  Dr.  Dellinger.  Its  big  advantage 
is  that  with  it  you  can  cut  out  a  station 
you  don't  want  to  hear  by  turning  the 
coil  around  a  vertical  axis.  In  this  case, 
the  directional  effect  is  very  marked. 
With  such  an  antenna  built  into  the 
cabinet  of  your  receiving  set,  your  an- 
tenna troubles  have  disappeared,  but 
with  such  a  small  antenna  you  must 
use   many   tubes. 

After  reading  the  rules  and  regulations 
(  Turn  to  page  70) 


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70 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


Approved"" 

by  the  Popular  Science 

Laboratories,  bywlell  Im 

known  setmaniifactui—  Ji_ 

evs  and  by  every  fan  g  ^         ~2^]£       ) 

MACNATflOM 


# 


MAGNATRONS  have  long  since 
established  themselves  in 
the  field  of  vacuum  tubes.  Their 
remarkably  uniform  high  qual- 
ity has  received  the  endorsement 
of  leading  manufacturers,  lab- 
oratories and  engineers.  Their 
excellent  performance  has  won 
for  MAGNATRONS  the  approval 
of  a  constantly  increasing  army 
of  radio  fans. 

The  men  entrusted  with  the  re- 
search responsible  for  MAGNA- 
TRON  excellence  have  devoted 
the  last  decade  to  vacuum  tube 
work.  They  know  good  tubes. 
The  entire  organization  knows 
how  to  build  good  tubes — and 
does.  MAGNATRONS  in  your 
set  will  convince  you  of  this  by 
the  improved  reception. 


Speaking  of  Your  Antenna! 

(Continued  from  preceding  page) 


of  the  National  Board  of  Fire  Under 
writers,  and  those  of  the  city  building 
and  electrical  departments  concerning 
antennas,  the  average  radio  user  would 
be  too  old  to  enjoy  his  hobby.  It  is 
necessary,  in  order  to  collect  the  insur- 
ance after  your  house  burns,  to  find  out 
what  the  Company  wants  in  the  way 
of  protection  and  install  it,  but  the 
radio  doctor's  words  on  this  subject  are 
encouraging. 

"Are  antennas  dangerous?"  he  asked. 
Then  he  answered:  "The  lightning 
hazard  is  practically  nil.  Only  for  out- 
side antennas  need  lightning  protection 
be  considered  at  all,  and  it  is  very  simple." 

The  article  needed  is,  like  men  who 
listen  to  the  neighbor's  loud  speaker 
instead  of  buying  a  radio  outfit,  small 
and  cheap.  It  is  called  a  "lightning 
arrester."  It  should  be  connected  be- 
tween the  antenna  and  the  ground  wire. 
A     transmitting     antenna     needs     more 


protection,  but  Dr.  Dellinger  was  dis- 
cussing only  those  used  by  average  folks 
exclusively  for  receiving.  Whatever 
slight  chance  there  may  be  of  an  an- 
tenna's coaxing  lightning  into  the  house 
will  operate  just  as  surely  in  the  case 
of  the  telephone  or  light  wires.  An  an- 
tenna will,  of  course,  draw  current  from 
an  electric  light  wire  if  it  touches  it, 
and  will  deliver  the  juice  into  the  body 
of  the  radio  fan  if  said  body  is  in  contact 
with  said  antenna. 

All  this,  from  an  expert  who  is  an 
expert,  is  very  satisfying  to  those  who 
hesitate  on  the  threshold  of  radio  recrea- 
tion, held  back  by  the  antenna  problem 
as  a  western  horse  is  restrained  by  a 
rope  corral  that  he  could  step  over  easily. 
All  that  needs  to  be  added  is  that  even 
the  best  antenna  will  not  prevent  inter- 
ference from  the  law  of  gravitation  if, 
in  climbing  a  tree  to  attach  the  antenna 
the  radio  bug  fails  to  watch  his  step. 
*     Tested  and  Approved  by  RADIO  AGE 


"The  Hidden  Voice,"  A  Radio 
Story 

(Continued  from  page  29) 

Mrs.  Stansbury  started  back  in  amaze- 
ment, almost  dropping  the  infant. 

"I  don't  know  what  it  means,  Mrs. 
Stansbury,"  volunteered  the  minister, 
who  knew  the  family  very  well.  "It 
seems  to  come  from  his  stomach." 

"Oh,  call  a  doctor,  quick,"  pleaded 
the  mother. 

"Help,  help!  Murder!"  came  from 
the  abandoned  carriage. 

"Ha,  we'll  get  at  the  mystery  now," 
said  the  policeman,  as  he  began  to  fumble 
about  among  the  pillows  and  around 
the  body  of  the  carriage.  Presently 
he  pulled  out  the  drawer  below  and 
produced  Jimmie's  miniature  receiving 
set. 

"Help!  I'm  being  kidnapped,"  came 
through  the  scrolled  front  of  the  cabinet. 

"Radio!"   cried  the  minister. 

"Yes,  that's  the  baby's  stomach," 
remarked  the  policeman,  with  a  grin. 
"Let's  investigate  further."  They  went 
into  the  house. 

"Why,  that's  Jimmie's  radio,"  said 
Mrs.  Kinnie,  much  to  the  wonder  and 
relief  of  her  daughter,  who  sat  hugging 
her  rescued  infant. 

"Is  that  so?  Where  is  he?"  inquired 
the     policeman. 

The  Mystery  Solved 

The  crowd  dashed  into  the  house  and 
ran  up  to  Jimmie's  room.  Without 
ceremony  they  opened  the  door  and  ran 
in,  only  to  find  that  young  man  convulsed 
in  mirth — as  much  mirth  as  could  be 
permitted  when  a  pair  of  headphones  are 
strapped   around   one's  head. 

For,  with  an  improvised  crystal  set, 
Jimmie  had  been  listening  with  increas- 
ing enthusiasm  and  satisfaction  to  his 
friend's  relentless  call  for  help  from  the 
broadcasting  station.  It  was  more  than 
Jimmie  had  expected  along  the  line  of 
co-operation.  But  now  that  it  was  forth- 
coming, he  was  gleeful  over  the  phenome- 
nal success  of  his  "idea." 

On  seeing  the  gathering,  his  smile 
quickly  disappeared,  but  he  soon  came 
"back  to  earth"  and  rendered  a  satis- 
factory explanation  of  the  hidden  voice 
in  the  baby  carriage.  Needless  to  say, 
praise  for  his  radio  ingenuity  was  whole- 
hearted. 

For  an  hour  or  more  an  eager  discus- 
sion of  the  affair  took  place,  in  the  house 
and  on  the  lawn,  for  the  crowd  that 
gathered  could  not  possibly  be  accom- 
modated indoors.  Meanwhile  the  police- 
man called  up  his  station  and  received 
this  message  from  the  desk  sergeant: 

"We  picked  up  a  woman  who  acted 
as  if  she  was  going  crazy.  She  admitted 
she  stole  the  child  and  abandoned  him 
because  he  talked  like  a  grown-up  and 
kept  calling  for  help." 

Meanwhile  also,  Mrs.  Stansbury  made 
an  important  discovery  and  communi- 
cated it  to  Jimmie. 

"Edward  must  have  chewed  his  zwie- 
back all  the  time,"  she  said;  "for  he  has 
cut  two  front  teeth  that  were  awful  hard 
coming  through." 

"Zwieback  can't  have  all  the  credit," 
Jimmie  retorted.  "This  really  is  a  case 
of  radio  teething!" 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


71 


And  Now  We  Have  Radio 
Cross -Words! 

(Continued  from  page  16) 

"eclecticism"     are     positively     not     ex- 
hibited  under  this  tent. 

Let's  Go! 

NOW  for  the  start.  You  will  see  that 
the  squares  form  horizontal  and 
vertical  lines  and  that  a  number  of  black 
squares  appear.  The  white  squares  each 
contain  a  letter  and  the  black  squares  are 
used  as  periods  with  a  full  word  between 
adjacent  squares.  This  is  the  case  either 
in  a  horizontal  or  vertical  direction.  The 
words  run  from  left  to  right,  or  from  top 
to  bottom,  starting  at  the  left  hand  edge 
of  the  figure  or  from  the  top.  The  space 
between  the  black  squares  must  contain 
a  full  word  and  each  of  the  white  squares 
must  be  filled.  All  squares  are  numbered 
horizontally    and    vertically. 

Just  as  an  example,  I  have  worked  out 
eight  of  the  words  in  the  upper  right 
hand  corner,  and  by  the  way,  this  con- 
tains the  only  unusual  two  words  in  the 
lot  submitted  to  you.  On  examination, 
you  will  see  that  complete  words  are 
formed  in  both  horizontal  and  vertical 
rows.  Thus,  the  word  "Loop"  is  hori- 
zontal word  (10),  the  word  "Earth"  is 
horizontal  (17),  etc.  Vertically,  we  have 
"Lab"  as  vertical  (10),  "Oral"  as  verti- 
cal (11),  and  so  on.  The  horizontal  and 
vertical  words  have  letters  in  common 
so  that  the  letter  (R)  forms  a  part  of 
both  "Earth"  and  "Oral."  The  letter 
(O)  is  a  part  of  "Loop"  and  also  of 
"Other."  I  have  worked  out  the  German 
trade  name  "Baha"  and  the  slang  word 
"Phan,"  thus  clearing  the  puzzle  of  any 
strange  words. 

Herewith  you  will  discover  the  defini- 
tions of  the  words  that  you  are  to 
use  in  working  out  the  puzzle,  and  these 
definitions  are  arranged  in  two  groups  for 
the  horizontal  and  vertical  lines.  When 
you  have  thought  of  a  word  that  means 
the  same  as  the  definition,  and  contains 
just  the  number  of  letters  as  the 
numbered  square,  then  mark  the  letters 
on  the  chart  as  shown  in  the  example. 
Horizontal  word  (1)  contains  four  letters 
and  the  same  is  true  of  vertical  word  (1). 
Horizontal  word  (5)  contains  five  letters 
and  vertical  word  (6)  has  only  two 
letters. 

In  the  list  of  horizontal  words,  horizon- 
tal (10)  reads,  "A  form  of  aerial."  This 
works  out  as  "Loop."  Vertical  (10)  is 
defined  in  the  list  as  "Experimenter's 
workroom  Abr."  The  full  word  is  labora- 
tory, and  the  abbreviation  is  "Lab," 
the  latter  occupying  the  three  vertical 
white  squares  under  (10).  Remember. 
The  words  extend  from  black  square  to 
black  square,  or  from  the  outer  edge  to 
the  following  black  square.     Hop  to  it. 

Send  in  your  solutions,  and  if  they 
reach  RADIO  AGE  by  January  25,  they 
will  be  published  with  the  solution  in  the 
March  issue.  Other  correct  solutions  will 
be  published  with  new  radio  puzzles  in 
future  issues  of  RADIO  AGE. 
(  Turn  to  next  page) 


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RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


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Dept.  2T302 


The 
Only 


True  Micrometer  Type 
VARIABLE  CONDENSER 


There  is  no  condenser  made,  nor  is  there  any 
vernier  attachment,  knob,  dial  or  other  con- 
trivance for  a  variable  condenser  which  gives 
one-twentieth  the  adjustment  possible  with  the 
BARRETT  &  PADEN  Micrometer  Con- 
denser. 

Stations  which  are  jammed  so  close  to  each 
other  on  the  dial  of  the  usual  condenser  that 
it  is  impossible  to  separate  them,  are  pulled 
apart  twenty  times  the  distance  on  your 
dial  when  you  use  a  BARRETT  &  PADEN 
Micrometer  Condenser.  Use  them.  You'll 
see  the  difference! 

Max.  Min. 

.0005  .000008 

.00035      .0000078 

.00025      .000007 

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$6.00  «J5 


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HEAR  BANKS  KENNEDY 

on  RADIO  AGE'S  progam 

From  KYW,  Feb.  7, 

Beginning  at  midnight 


(Continued  from  preceding  page) 


HORIZONTAL  LINES 

Magnitude  of  surface. 

A  conductor  made  by  twisting  a  num! 


r  of  small  wires 


44. 


A  form  of  aerial. 

Carried    by    a    ship. 

An  intermediate  connection  to  a  coil. 

To  ground. 

Doing  nothing. 

German  trade  mark  for  a  make  of  radio  apparatus. 

Abbreviation  of  diameter. 

Age  or  period. 

First  name  (abbreviated)  of  the  Governor  of  Illinois 

Small     negative    particles. 

Debt. 

Technical  man  (Abr.). 

Pitch. 

Not  out. 

Potential  (Abr.). 

Speaking  apparatus  (Abr.). 

Indefinite  article. 


45.  To  c 

47.  Organ  of  hearing. 

48.  Women's  husbands. 

49.  Self. 

60.  Oscillation  constant  (Abr.). 

51.  One  of  the  connections  on  a  receiver  (Abr.). 

53.  Conjunction. 

55.  Editor  (Abr.). 

56.  Patent  (Abr.). 

57.  Cover. 

59.  Atmosphere. 

61.  Above  (Prefix). 
64.  Alternator  (Abr.). 

66.  Chart. 

67.  Move  fast. 

08.  Pressing  collection. 

70.  Temper  of  mind  (Manner). 

73.  DA-DIT-DIT-DAA. 

74.  Energy. 

75.  British  Thermal  unit  (Abr.). 

77.  The  subject  of  this  magazine. 

78.  Abbreviation  for  single  pole,  single  throw  switch, 

79.  A  metal  alloy. 

80.  Earth's  sutelito. 

VERTICAL  LINES 

1.  Contained  in  a  storage  battery. 

2.  Communication  by  Hertzian  waves. 

3.  A  well  known  reflex  circuit. 

4.  Old. 

6.  By. 

7.  Battery  (Abr.). 

8.  Low  potential  (Abr.). 

10.  Experimenter's  work  room  (Abr.). 

11.  Pertaining  to  the  mouth. 

12.  Different. 

13.  A  name  often  used  for  a  radio  "Nut." 
19.  Part  of  the  verb  "to  be." 

21.  Amperes,  Volts,  Ohms  (Abr.). 

24.  A   substance    which    cannot   be   decomposed    by   any 
nown  method. 

25.  Victorious  Army  Aviator. 

26.  Unit  of  work. 

27.  A  wire  for  collecting  radio  waves. 

30.  Female  sheep. 

31.  A  hign  explosive. 

32.  Prefix  meaning  salt.     Used  in  dry  battery  electrolytes. 

33.  Space  occupied  by  magnetic  forces. 
38.  Positive  electrode. 

Naval  Radio  Station  Call  number. 
A  hobby. 

To  grow  old. 

Space  between  two  parts. 

Moisture  found  in  plants  (Juice). 


42. 
43. 

44. 
61. 

52. 

54.      Irr 

57.  Drinking  vessel. 

58.  By. 

60.  Annoying    noise    made    by    tube    set    which    affects 
neighboring   aerials   (slang     phrase). 

61.  To  droop. 

62.  To  polish  or  shine. 

63.  The  name  of  the  stage  which  amplifies  at  voice  fre- 

Amperes  (Abr.). 

Pulls  along. 

An  extinct  bird. 

A  gaseous  element  used  in  testing  spark  plugs. 

Defector  (Abr.). 

Greek  letter  corresponding  to  "E". 

A    mechanical    part   used   for   giving    a   reciprocating 

to  another  part. 

Brass  (Abr.). 

Objective  pronoun. 


"Polyplugs"  on  Market 

The  well-designed  and  popular  priced 
"Polyplug,"  the  product  of  the  Polymet 
Manufacturing  Corporation,  70-74  La- 
fayette Street,  New  York  City,  has  in- 
duced many  manufacturers  of  Loud 
Speakers  to  furnish  Phone  Plugs  with 
their  units.  As  the  Phone  Plug  is  such 
an  essential  part  of  the  Loud  Speaker, 
it  is  only  a  matter  of  a  short  period  when 
every  Loud  Speaker  manufacturer  will 
include  a  Plug  with  his  product. 

The  Polymet  Manufacturing  Corpora- 
tion has  also  brought  out  two  additional 
Radio  Units,  which  have  been  enthu- 
siastically welcomed  by  manufacturers  of 
Radio  Sets.  *  This  is  a  Rheostat  called 
the  "E-Z"  Stat,  and  a  Potentiometer 
called  the  "E-Z"  Ometer. 

The  popularity  of  these  two  units  is 
due  to  the  construction  which  helps  the 
manufacturer  of  sets  speed  up  his  as- 
sembly production.  These  items  remove 
all  the  fuss  of  adjustments  because  the 
adjustment  is  permanently  fixed. 

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RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


,'hether  you  plan  to  build  or 
to  buy  a  receiving  set,  it  will  pay 
f  you  to  know  something  about  the 
]y  insides"  of  radio.  This  booklet 
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In  this  bulletin  is  full  information 
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before. 

KARAS  HARMONIK 
Amplifies  low,  middle  and  high 
tones — allto  the  same  big  volume, 
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tones  of  music.  Price  $7.00.  Write 
Karas  Electric  Co.,    Depl.  57-99  4042  N.Rockwell Sl„  Chicago 


A  Unit  for  Measuring 
Capacity 

(Continued  from  page  19) 

X,   as   was  shown   in   the  foregoing    ex- 
ample of  impedance,  or  as  follows: 

Coil  X  =  100  Ohms. 

Dial  reading  42  — 

Coil  Y  =  .58x100  or  58  Ohms,  or 

Coil  X  =  50  Ohms. 

Dial  Reading  42  + 

Coil  Y  =  1.42x,50  or  71  Ohms. 

To  Measure  Capacity 

Connect  a  known  capacity  to  terminals 
XI  and  X2.  Say  .001  microfarad,  then 
connect  the  unknown  capacity  to  ter- 
minals Yl  and  Y2,  moving  the  pointer 
until  the  silent  period  is  found.  If  this 
should  fall  on  50 — ,  then  the  capacity 
of  Y  will  be 

Condenser  X  =  .001  M  F 

Dial  reading  50  — 

Capacity  Y  =  .50x.001  M  F  or  .0005 
M  For 

Condenser  X  =  .001  M  F 

Dial  reading  80  + 

Capacity  Y  =  1.8x.001  M  F  or  .0018 
M  F. 

Many  other  forms  of  measurement 
can  be  made  on  this  instrument  when  a 
known  quantity  is  connected  across 
terminals  XI  and  X2  using  the  formulae, 
"Y"   =  Dial  reading  X  "X" 

Remembering  that  readings  from  the 
"— "  side  of  the  scale  will  always  be  in 
the  form  of  a  decimal  or  hundredth 
part  of  "X"  and  that  "Y"  is  always  less 
than  "X,"  thus  "Y"  =  Dial  reading 
X  "X"  while  the  readings  from  the 
"+"  side  of  the  scale  will  always  be 
1  +  Dial  reading  or  one  and  a  decimal 
or  hundredth  times  "X."  Thus  "Y" 
=  "X"  +  dial  reading  X  "X"  and  "Y" 
will  always  be  greater  than  X. 


Jack 


Nelson  Will  Get  a 
Laugh  Here 

(Continued  from  page  32) 

sary  that  you  confine  your  votes  to  con- 
testants whose  names  appear  in  this  list. 
Possibly  your  favorite  is  awaiting  your 
votes  to  boost  him  to  a  position  in  the 
first  division.  Such  apparently  was  the 
case  with  Art  Linick,  whose  name  did 
not  appear  on  this  page  of  our  preceding 
issues. 

RADIO  AGE  has  definitely  decided  on 
a  unique  shield  as  an  award  for  the  final 
victor  of  this  contest.  Who  are  you  going 
to  help  win  this  token  of  popular  favor? 

While  some  of  the  contestants  seem 
to  hold  their  positions  through  a  "steady 
stream  of  votes  each  month,  still  a  careful 
count  of  the  ballots  shows  that  each 
month  indicates  a  wave  of  popular  favor 
for  some  individual  who  gathers  more 
votes  than  any  other  through  that  period. 

By  way  of  creating  greater  interest  in 
this  contest,  a  year's  free  subscription  to 
RADIO  AGE  will  be  given  to  the  first 
three  readers  whose  ballots  name  the 
candidate  receiving  the  greatest  number 
of  votes  during  the  period  from  January 
16  to  February  15.  So  get  busy  and  send 
in  your  ballots. 
*     Tested  and  Approved  by  RADIO   AGE     * 


TRY  US! 
.ADIO  DEALERS! 

We  are  exclusive 
Radio  Jobbers 
and  DO  NOT 
RETAIL. 

Howard  —  Crosley 
Liberty — Day-Fan 

Dynergy 
Receiving  Sets 

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We    Sell    to    Dealers    Only. 

Write  for  Catalog. 

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6  N.  Franklin  St.,   Chicago 


recise 
Multiformer 


Price  $20.00 

For  the  McLaughlin  single  control 
Super-Het  receiving  set  as  described 
in  Q.  S.  T.  and  Radio. 

The  sensation  of  every  Radio  show. 
Instruction  Book  $1.00.  All  Europ- 
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Inductance  Coils 

PER  SET 

Cotton  $8.50         Silk  $10.00 

PRECISE  MFG.  CORP. 

The  BARSOOK  CO. 

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53  W.  Jackson  Blvd.       Chicago,  III. 


THE  RADIO  AGE 

ANNUAL 

for  1925 

With  120  pages  of  hookups, 
"How  to  do  it"  articles,  be- 
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blueprint  hookups  in  color. 

NOW  READY— AT   ONE  DOL- 
LAR A  COPY 


74 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA 

KDPM 

KDPT 

KDYL 

KDYM 

KDYQ 

KDZB 

KDZE 

KDZI 

KDZR 

KFAD 

KFAE 

KFAF 

KFAJ 

KFAR 

KFATJ 

KFAW 

KFAY 

KFBB 

KFBC 

KFBE 

KFBG 

KFBK 

KFBL 

KFBS 

KFBU 

KFCB 

KFCC 

KFCF 

KFCL 

KFCP 

KFCV 

KFCZ 

KFDD 

KFDH 

KFDJ 

KFDM 

KFDX 

KFDY 

KFDZ 

KFEC 

KFEK 

KFEL 

KFEQ 

KFER 

KFEY 

KFFP 

KFFR 

KFFV 

KFFY 

KFGB 

KFGC 

KFGD 

KFGH 

KFGQ 

KFGX 

KFGZ 

KFHA 

KFHH 

KFHJ 

KFHL 

KFHR 

KFI 

KFIF 

KFIO 

KF1Q 

KFIU 

KFIX 

KFIZ 

KFJB 

KFJF 

KFJI 

KFJK 

KFJL 

KFJM 

XFJR 

KFJX 

KFJY 

KFJZ 

KFKA 

KFKB 

KFKQ 

KFKU 

KFKV 

KFKX 

KFKZ 

KFLA 

KFLB 

KFLD 

KFLE 

KFLQ 

KFLR 

KFLU 

KFLV 

KFLX 

KFLZ 

KFMB 

KFMQ 

KFMR 

KFMT 

KFMW 

KFMX 

KFNF 

KFNG 

KFNJ 

KFNL 

KFNV 

KFNY 

KFNZ 

KFOA 

KFOC 

KFOD 

KFOJ 

KFOL 

KFON 

KFOO 

KFOP 

KFOR 

KFOT 

KFOU 

KFOX 

KFOY 

KFOZ 

KFPB 

KFPG 

KFPH 

KFPL 

KFPM 

KFPN 

KFPO 

KFPP 

KFPR 

KFPT 

KFPV 

KFPW 

KFPX 

KFPY 


Westinghouse  Electric  &  Mfg.  Co East  Pittsburgh  326 

Westinghouse  Electric  &  Mfg.  Co Cleveland,  Ohio  270 

Southern  Electrical  Co 9an  Diego,  Calif.  244 

Newhouse  Hotel Salt  Lake  City,  Utah  360 

Savoy  Theatre San  Diego,  Calif.  280 

Oregon   Institute  of  Technology Portland,   Oreg.  360 

Frank  E.  Siefert Bakersfield,  Calif.  240 

Rhodes  Department  Store Seattle,  Wash.  270 

Electric  Supply  Co Wenatchee,  Wash.  360 

Bellingham  Publishing  Co Bellingham.  Wash.  261 

McArthur  Bros.  Mercantile  Co Phoenix,  Ariz.  360 

State  College  of  Washington Pullman,  Wash.  330 

Western   Radio  Corporation Denver,  Colo.  278 

University  of   Colorado Boulder,   Colo.  360 

Studio  Lighting  Service  Co.  (O.  K.  Olsen) Hollywood,  Calif.  280 

Boise  High  School Boise.  Idaho  270 

The  Radio  Den  <W.  B.  Ashford) Santa.  Ana.  Calif.  280 

Virgin's  Radio  Service Medford,  Ore.  283 

F.  A.  Buttrey  &  Co Havre,  Mont.  360 

W.  K.  Azbill San  Diego,  Calif.  278 

Reuben  H.  Horn San  Luis  Obispo,  Calif .  242 

First  Presbyterian  Church Tacoma,  Wash.  360 

Kimball-Upson  Co Sacramento.  Calif.  283 

Leese  Bros Everett,  Wash.  224 

Trinidad  Gas  &  Electric  Supply  Co.  and  Chronicle  News Trinidad,  Colo.  280 

The  Cathedral Laramie,  Wyo.  283 

Nielson  Radio  Supply  Co Phoenix,  Ariz.  238 

The   First   Congregational   Church Helena.    Mont.  248 

Frank  A.  Moore Walla  Walla,  Wash.  256 

Leslie  E.  Rice Los  Angeles,  Cal.  236 

Ralph   W.    Flygare Ogden,  Utah  360 

Fred  Mahaffey,  Jr Houston.  Texas  360 

Omaha  Central  High  School Omaha,  Nebr.  258 

St.  Michaels  Cathedral Boise,  Idaho  252 

University  of  Arizona Tuscon,  Ariz.  368 

Oregon  Agricultural  College Corvallis,  Oreg.  360 

Magnolia    Petroleum    Co Beaumont,    Tex.  306 

First  Baptist  Church Shreveport,  La.  360 

South  Dakota  State  College Brookings,  S.  Dak.  360 

Harry  O.  Iverson Minneapolis.  Minn.  231 

Meier  &  Frank  Co Portland.  Oreg.  248 

Augsbury    Seminary Minneapolis.    Minn.  261 

Winner  Radio  Corp Denver,  Colo.  254 

J.  L.  Scroggin Oak.  Nebr.  268 

Auto  Electric  Service  Co Fort  Dodge,  Iowa  231 

Bunker  Hill  &  Sullivan  Mining  and  Concentrating  Co Kellogg,  Idaho  360 

First  Baptist  Church Moberly,  Mo.  266 

Nevada  State  Journal  (Jim  Kirk) Sparks.  Nev.  226 

Graceland   College Lamoni,  Iowa  280 

Pincus     &     Murpbey     Music     House Alexandria.     La.  275 

Heidbreder   Radio  Supply  Co Utica.  Neb.  224 

Louisiana  State  University Baton  Rouge,  La.  254 

Cbickasha  Radio  &  Electric  Co Chickasba,  Okla.  248 

Leland  Stanford  University Stanford  University,  Calif.  273 

Crary  Hardware  Co Boone,  Iowa  226 

First   Presbyterian   Church Orange,  Tex.  250 

Emmanuel  Missionary  College Berrien  Springs,  Mich.  286 

Western  State  College  of  Colorado Gunnison.  Colo.  252 

Ambrose  A.  McCue Neah  Bay.  Wash.  261 

Fallon  &  Co Santa  Barbara.  Calif.  360 

Penn     College Oskaloosa,     Iowa  240 

Star  Electric  &  Radio  Co Seattle.  Wash.  283 

E.  C.  Anthony,   Inc Los   Angeles,  Calif.  469 

Benson   Polytechnic  Institute Portland,   Oregon  248 

North  Central  High  School Spokane,  Wash.  252 

First  Methodist   Church Yakima.   Wash.  242 

Alaska  Electric  Light  &  Power  Co Juneau,  Alaska  226 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints. Independence.  Mo.  240 

Daily  Commonwealth  and  Oscar  A.  Huelsman Fon  Du  Lac.  Wis.  273 

Marshall  Electrical  Co Marahalltown,  Iowa  248 

National  Radio  Manufacturing  Co Oklahoma  City,  Okla.  252 

Liberty  Theatre  CE.  E.  Marsh) Astoria,  Oreg.  252 

Delano   Radio   and   Electric   Co Bristow,  Okla.  233 

Hardsacg  Manufacturing  Co Ottumwa,  Iowa  242 

University  of   North   Dakota Grand   Forks,    N.   Dak.  280 

Ashley  C.  Dixon  &  Son Stevensville.  Mont,  (near)  258 

Iowa  State  Teacher's  College Cedar  Falls.  Iowa  280 

Tunwall  Radio  Co Fort  Dodge,  Iowa  246 

Texas  National  Guard,  One  hundred  and  twelfth  Cavalry. Fort  Worth  Texas  254 

Colorado  State  Teachers  College Greeley,  Colo.  273 

Brinkley- Jones   Hospital    Association Milford,   Kans.  286 

Conway  Radio  Laboratories  (Ben  H.  Woodruff) Conway.  Ark.  250 

The    University    of    Kansas • Lawrence,    Kans.  275 

F.  F.  Gray Butte.  Mont.  283 

Westinghouse  Electric  &  Manufacturing  Co Hastings,  Nebr.  341 

Nassour   Bros.    Radio  Co Colorado  Springs,  Colo.  234 

Abner  R.  Willson Butte,  Moot.  283 

Signal  Electric  Manufacturing  Co Menominee.  Mich.  248 

Paul  E.  Greenlaw Franklinton,   La.  234 

National  Educational  Service Denver,  Colo.  268 

Bizzell  Radio  Shop Little  Rock,  Ark.  261 

University  of  New  Mexico Albuquerque,  New  Mexico  254 

Rio  Grande  Radio  Supply  House San  Benito,  Texas  236 

Rev.  A.  T.  Frykman Rockford.  111.  229 

George  Roy  Clough Galveston,  Tex.  240 

Atlantic   Automobile   Co Atlantic,   la.  273 

Christian  Churches ■ Little  Rock,  Ark.  254 

University  of  Arkansas Fayette ville.  Ark.  263 

Morningside  College Sioux  City,  Iowa  261 

Dr.  George  W.  Young Minneapolis,  Minn.  231 

M.   G.   Sateren Houghton,    Mich.  266 

Carleton  College Northfield.  Minn.  283 

Henry  Field  Seed  Co Shenandoah,  Iowa  266 

Wooten's   Radio  Shop Coldwater,  Miss.  254 

Central  Mo.  State  Teachers  College Warrensburg.  Mo.  234 

Radio  Broadcast  Ass'n Paso  Robles,  Calif.  240 

L.  A.  Drake  Battery  »nd  Radio  Supply  Shop Santa  Rosa.  Calif.  234 

Montana  Phonograph    Co Helena.   Montana  261 

Royal  Radio  Company Burlingame.  Calif.  231 

Rhodes  Department  Store Seattle.Wash.  455 

First   Christian    Church Whittier,   Calif.  236 

Radio  Shop Wallace,  Idaho  224 

Moberly  High  School  Radio  Club Moberly,  Missouri  246 

Leslie  M.   Schafbush Marengo,   Iowa  234 

Echophone  Radio  Shop Long  Beach,  Calif.  234 

Latter  Day  Saints  University Salt  Lake  City,  Utah  261 

Rohrer       Elec.       Co Marshfield       Ore.  240 

David  City  Tire  &  Electric  Co David  City,  Nebraska  226 

College  Hill   Radio   Club Wichita.   Kansas  231 

Hommel  Mfg.  Co Richmond,  Calif.  254 

Board  of  Education,  Technical  High  School Omaha,  Nebraska  248 

Beacon  Radio  Service St.  Paul.  Minn.  226 

Leon  Hudson  Real  Estate  Co Fort  Smith,  Ark.  233 

Edwin   J.    Brown Seattle,    Wash.  224 

Garretson  and   Dennis Los   Angeles,  Calif.  238 

Harold  Chas.  Mailander Salt  Lake  City.  Utah  242 

C.   C.   Baxter Dublin.  Texas  242 

The  New  Furniture  Co Greenville,  Texas  242 

Missouri  National  Guard Jefferson   City,  Mo.  242 

Colorado  National  Guard -.  .Denver.  Colo.  231 

G.  &.  G.  Radio  &  Electrio  Shop Olympia,  Washington  236 

Los  Angeles  Co.  Forestry  Dept Los  Angeles,  Calif.  231 

Cape    &    Johnson Salt    Lake    City.  Utah  268 

Heintz  &  Kohlmoos,  Inc San  Francisco.  Calif.  236 

St.  Johns  M.  E.   Church Carterville,  Mo.  268 

First   Presbyterian    Church Pine   Bluff,    Ark.  242 

Symons  Investment  Co Spokane,  Wash.  283 


KFQA  The  Principia St.  Louia,  Mo.  264 

KFQB  The  Searchlight  Publishing  Co Fort  Worth,  Tex.  221 

KFQC  Kidd  Brothers  Radio  Shop Taft,  Calif.  258 

KFQD  Chovin  Supply  Co Anchorage.  Alaska  20T 

KFQE  Dickenson-Henry  Radio  Laboratories Colorado  SpringB,  Colo.  224 

KFQG  Southern  Calif.  Radio  Ass'n Loa  Angelas,  Calif.  226 

KFQH  Radio    Service    Co Burlingame ,  Calif .  231 

KFQK.  Democrat  Leader Fayette.  Mo.  236 

KFQL  Oklahoma  Free  State  Fair  Assn Muskogee.  Okla.  2S2 

KFQM  Texas  Highway  Bulletin Austin,  Tex.  268 

KFQN  Third  Baptist  Church Portland,  Ore.  283 

KFQO  Meier    Radio   Shop Russell,   Kans.  261 

KFQP  G.   S.   Carson,  Jr Iowa    City.   la.  224 

KFQR  Walter  LaFayette  Ellis Oklahoma   City,   Okla.  250 

KFQT  Texas  National  Guard Denison,   Texas  252 

KFQU  W.  Riker Holy  City,  Calif.    234 

KFQV  Omaha  Grain  Exchange    (Portable) Omaha.  Nebr.  231 

KFQW  C.  F.  Knierim North  Bend.  Wash.  248 

KFQX  Alfred    M.    Hubbard Seattle,    Wash.  233 

KFQY  Farmers  State  Bank Belden.Neb.  273 

KFQZ  Taft  Radio  Co Hollywood.  Calif.  240 

KFRI  The  Reynolds  Radio  Co.  Inc.  Portable  Station Denver.    Col.  224 

KFRJ  Guy  Simmons,  Jr Conway,  Ark.  250 

KFRM  James  F.  Boland Fort  Sill,   Okla.  263 

KFRN  M.  Laurence  Short Han  ford,  Calif .  224 

KFRO  Curtis  Printing  Co Ft.  Worth,  Tex.  246 

KFRX  J-    Gordon    Klemgard Pullman.    Wash.  217 

KFRY  The  Mexico  College  of  Agriculture State  College.  N.  M.  266 

KFRZ  The  Electric  Snop Hartington,  Neb.  222   ( 

KFUL  Thomas  Goggan  <fe  Bros Galveston,  Tex.  258 

KFUM  W.  D.  Corley Colorado  Springs.  Colo.  242 

KFUO  Concordia    Seminary St.     Louis.     Mo.  54S 

KFRW  United  Churched  of  Olympia Olympia,  Wash.  220 

KFSG  Angelus  Temple Los  Angeles,  Calif.  278 

KFS Y  The  Van  Blaricon  Co Helena,  Mont.  261 

KGB  Tacoma  Daily  Ledger Tacoma.  Wash.  252 

KGG  Hallock  &  Watson   Radio  Service Portland,  Oreg.  360 

KGO  General   Electric    Co Oakland,    Calif.  312 

KGU  Marion  A.  Mulrony Honolulu,  Hawaii,  Waikiki  Beach  360 

KGW  Portland  Morning  Oregonian Portland,   Oreg.  492 

KG  Y  St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy,  Wash.  258 

KHJ  Times-Mirror    Co Los    Angeles,    Calif.  395 

KHQ  Louis    Wasmer Seattle,    Wash.  360 

KJQ  C   O.  Gould Stockton,    Calif.  273 

KJR  Northwest  Radio  Service  Co Seattle,  Wash.  283 

KLS  Warner  Brothers    Radio  Supplies  Co Oakland,   Calif.  360 

KLX  Tribune  Publishing  Co Oakland,  Calif.  509 

KLZ  Reynolds  Radio  Co Denver,  Colo.  283 

KM  J  San  Joaquin  Light  &  Power  Corp Fresno,  Calif.  248 

KMO  Love  Electric  Co Tacoma.  Wash.  360 

KNT  Walter  Hemrich Kukah  Bay.  Alaska  263 

KNX  Los  Angeles  Evening  Express Los  Angeles,  Calif.  337 

KOB  New  Mexico  College  of  Agriculture  &  Mechanic  Arts.  .State  College,  N.Mex.  360 

KOP  Detroit  Police  Department Detroit.  Mich.  286 

KPO  Hale  Bros San  Francisco.  Calif.  423 

KQP  Apple  City  Radio  Club Hood  River.  Oreg.  360 

KQV  Doubleday-Hill  Electric  Co Pittsburgh,  Pa.  270 

KQW  Charles  D.  Herrold San  Jose,  Calif.  240 

KRE  V  C  Battery  &  Electric  Co Berkeley.  Calif.  275 

KSAC  Kansas  State  Aericultnral  College Manhattan,  Kans.  341 

KSD  Post  Dispatch  (Pulitzer  Pub.  Co.) St.  Louis,  Mo.  546 

KTW  First  Presbyterian    Church Seattle.  Wash.  360 

KUO  Examiner  Printing  Co San  Francisco.  Calif.  360 

KWG  Portable  Wireless  Telephone  Co Stockton,  Calif.  360 

KWH  Los    Angeles   Examiner Los   Angeles,    Calif.  360 

KYQ  Electric    Shop Honolulu,    Hawaii  270 

K YW  Westinghouse  Electrio  &  Mfg.  Co Chicago.  111.  536 

KZM  Preston    D.    Allen Oakland.    Calif.  360 

WAAB  Valdernar    Jensen New    Orleans,    La.  268 

WAAC  Tulane  University New  Orleans.  La.  360 

WAAD  Ohio   Mechanics    Institute Cincinnati,  Ohio  360 

WAAF  Chicago  Daily  Drovers  Journal Chicago,  III.  286 

WAAM  I.  R.  Nelson  Co Newark,  N.  J.  263 

WAAN  University  of  Missouri Columbia.  Mo.  254 

WAAW  Omaha   Grain   Exchange Omaha,    Nebr.  286 

WABB  Harrisburg  Sporting  Goods  Co Harrisburg,  Pa.  266 

WABD  Parker  High  School Dayton,  Ohio  283 

WABH  Lake  Shore  Tire  Co Sandusky.  Ohio  240 

WABI  Bangor  Railway  &  Electric  Co Bangor.  Me.  240 

WABL  Connecticut   Agricultural    College Storrs.    Conn.  283 

WABM  F.  A.  Doherty  Automotive  and  Radio  Equipment  Co Saginaw,  Mich.  254 

WABN  Ott   Radio,   Inc LaCrosse,  Wis.  244 

WABO  Lake  Avenue  Baptist  Church Rochester.  N.  Y.  283 

WABP  Robert  F.  Weinig Dover,  Ohio  266 

WABQ  Haverford  College.  Radio  Club Haverford,  Pa.  261 

WABR  Scott  High  School,  N.  W.  B.  Foley Toledo,  Ohio  270 

W ABU  Victor  Talking  Machine  Co Camden.  N.  J.  226 

WABW  College  of  Wooster Wooster.  Ohio  234 

WABX  Henry  B.  Joy Mt.  Clemens,  Mich.  270 

WABY  John  Magaldi,  Jr Philadelphia,  Pa,  242 

WABZ  Coliseum  Place  Baptist  Church New  Orleans,  La.  263 

WAHG  A.  H.  Grebe  &  Co Richmond  Hill,  N.  Y.  316 

WBAA  Purdue  University W.   Lafayette.  Ind.  283 

WBAH  The  Dayton  Co Minneapolis.  Minn.  417 

WB AN  Wireless  Phone  Corp Paterson,  N.  J.  244 

WBAO  James     Millikin     University Decatur,    111.  360 

WBAP  Wortham-Carter  Publishing  Co.  (Star  Telegram) Fort  Worth,  Tex.  476 

WBAV  Erner&  Hopkins  Co Columbus,  Ohio  423 

WBAX  John  H.  Stenger,  Jr Wilkes-Barre,  Pa.  254 

WBAY  Western  Electric  Co New  York,  N.  Y.  492 

WBBD  Barbey  Battery  Service Reading,  Pa.  234 

WBBG  Irving  Vermilya Mattapoisett,  Mass.  248 

WBBH  J.  Irving  Bell Port  Huron.  Mich.  246 

WBBL  Grace  Covenant  Presbyterian   Church Richmond.  Va.  283 

WBBM  H.    Leslie  Atlass Chicago.  HI.  226 

WBBN  Blake.  A.  B. Wilmington,  N.  C.  275 

WBBP  Petoskey    High    School Petoskey ,  Mich.  246 

WBBR  Peoples   Pulpit   Asso Rossville,    N.  Y.  273 

WBBS  First   Baptist    Church New    Orleans, La.  252 

WBBU  Jenkfl    Motor   Sales    Co Monmouth,  111.  224 

WBBV  Johnstown  Radio  Co Johnstown.  Pa.  245 

WBBX  Ruffner     Junior     High     School Norfolk,  Va.  222 

WBBY  Washington  Light  Infantry  Co.    'B"  118th  Inf Charleston.  S.  C.  268 

WBBZ  Noble  B.  Watson Indianapolis.  Ind.  227 

WBGA  Jones  Elec.  &  Radio  Mfg.  Co Baltimore,  Md.  254 

WBCN  Foster  &  McDonald Chicago,  HI.  266 

WBL  T  &  H  Radio  Co.  .       Anthony,  Kans.  254 

WBR  Pennsylvania  State  Police Butler.  Pa.  286 

WBS  D.  W.  May.  Inc Newark,  N.  J.  260 

WBT  Southern    Radio    Corp Charlotte.    N.    C.  360 

WBZ  Westinghouse     E.    &     M.     Co Springfield,     Mass.  337 

WCAD  St.  Lawrence  University Canton,  N.  Y.  280 

WCAE  Kaufmann  A  Baer  Co Pittsburgh,  Pa.  462 

WCAG  Clyde  R.  Randall New  Orleans,  La.  268 

WCAH  Entrekin  Electric  Co Columbus.  Ohio  266 

WCAJ  Nebraska  Wesleyan  University University  Place,  Nebr.  283 

WCAK  Alfred  P.  Daniel Houston,  Texas  263 

WC AL  St.  Olaf  College Northfield,   Minn.  360 

WC AO  Sanders  «fc  Stayman  Co Baltimore,  Md.  275 

WCAP  Chesapeake  &  Potomac  Telephone  Co Washington,  D.  C.  469 

WCAR  Alamo  Radio  Electric  Co San  Antonio.  Tex.  263 

WCAS  W.  H.  Dunwoody  Industrial  Institute. Minneapolis,  Minn.  280 

WCAT  State  College  of  Mines Rapid  City,  S  Dak.  240 

WCAU  Durham   &    Co Philadelphia,  Pa.  286 

WCAV  J.  C.  Dice  Electrio  Co Little  Rock,  Ark.  263 

WCAX  University  of   Vermont Burlington ,  Vt.  360 

WCAZ  Carthage   College Carthage.  Til.  246 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


75 


CLASSIFIED  ADVERTISEMENTS 


Don't  overlook  the  value  of 
RADIO  AGE'S  classified  adver- 
tisements. Many  such  messages 
have  paved  the  way  to  independent 
incomes. 

The  classified  advertising  rates 
are  but  ten  cents  per  word  for  a 
single  insertion.  Liberal  discounts 
are    allowed    on    three,    six     and 


twelve  -time  insertions,  of  five, 
fifteen  and  thirty  per  cent,  res- 
pectively. Unless  placed  through 
an  accredited  advertising  agency, 
cash  should  accompany  all  orders. 
Name  and  address  must  be  in- 
cluded at  foregoing  rates  and  no 
advertisement  of  less  han  ten 
words   will   be   accepted. 


RADIO  OFFERS 


15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.  Every  item  guaranteed.  Tell  us  your  needs. 
IMPERIAL  RADIO  COMPANY,  Delaware,  Ohio. 

RADIO  SETS.  Our  prices  save  you  money.  Lists 
free.     The  Radio  Shoppe,  Box  645,  East  Liverpool,  Ohio. 

JOIN  THE  RADIO  Parts  Exchange  Club.  Your  parts 
inspected  (Fee  i5c),  and  exchanged  for  the  parts  you 
need.  What  have  you;  what  parts  do  you  require? 
Write  us  for  details. 

The  Radio  Parts  Exchange  Club,  112  So.  Homan  Ave, 
Chicago. 

RADIO  CIRCUITS 

SPECIAL  FOR  FEBRUARY 
The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne,  fully 
Illustrated,  and  RADIO  AGE,  for  52.50.     Price  of  book- 
let alone  is  50c.     Send  check,  currency  or  money  order 
ts  RADIO  ACE,  500  N.  Dearborn  Street,  Chicago. 

MISCELLANEOUS 

158  Genuine  Foreign  Stamps.  Mexico  War  Issues. 
Venezuela,  Salvador  and  India  Service.  Guatemala, 
China,  etc.,  only  5c.  Finest  approval  sheets,  50  to 
60  percent.  Agents  Wanted.  Big  72-p.  Lists  Free. 
We  Buy  Stamps.  Established  20  Years.  Hussman 
Stamp  Co.,  Dept.  152,  St.  Louis,  Mo. 

RADIO  SALESMEN  and  SET  BUILDERS— We  need 
you  and  you  need  us.  If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  49,  1027 
N.  State  St..  Chicago,  111. 


90c  an  hour  to  advertise  and  distribute  samples  to  con- 
sumer. Write  quick  for  territory  and  particulars. 
American  Products  Co. ,  2130  American  Building,  Cin- 
cinnati, Ohio. 


nples    supplied. 
ite  today  Tanne 


■  this  territory  to  sell  wonderful 
en's.  Children's  shoes  direct,  sav- 
er 40%.  Experience  unnecessary. 
Big  weekly  permanent  income, 
s  Mfg.  Co.,  1334C.  St.,  Boston,  Mass. 


BUSINESS    OPPORTUNITIES 


DEALERS— Write  for  our  illustrated  catalog  of  reliable 
Radio  Merchandise.  Rossiter-Manning  Corporation, 
Dept.  D,  1830  Wilson  Ave.,  Chicago,  111.  


RADIO— Join 


leB    organization    and    make    big 
every  county  to  sell  well 


advertised  sets  and   parts 
facturers.     Widener     of 

weekly.      You   can   do   as    „c   „.    «...«■■      ... — . 

for  catalog,  and  discounts.  Name  your  county.  Wave 
land  Radio  Company,  Div.  50,  1027  No.  State  St.,  Chi 
cago,  III. 


.de  by  the  leadi..b 

City     makes     $150.00 
better.     Write   today 


NEW  WRITERS  WANTED— Articles,  stories,  poems, 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No  bunk).  NOT  A  CORRES- 
PONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
azines. Send  self  addressed  envelope  for  list  of  100 
subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Los 
Angeles,   Calif. 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parts  and  plans— complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake,  Chicago. 


A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,   111. 


Classified  ad  copy  for  March  Radio  Age  must  reach  us  by  January  27. 


CFAC 
CFCA 
CFCF 

CFCH 
CFCJ 
CFCK 
CFCN 
CFCQ 
CFCR 
CFCT 
CFCU 
CFCW 
CFDC 
CFHC 
CFLC 


Canadian  Broadcasting  Stations 


Calgary  Herald.  Calgary,  Alberta 430 

Star  Pub.  &  Prig.  Co..  Toronto.  Ontario 400 

Marconi  Wireless  Tel.  Co.  of  Canada,  Montreal, 

Quebec 440 

Abitibi  Power  &  Paper  Co.,  Iroquois  Fails,  Ont.  400 

La  Cie  de  L'Evenenient,  Quebec.  Quebec 410 

Radio  Supply  Co.,  Edmonton,  Alberta 410 

W.  W.  Grant  Radio  (Ltd.),  Calgary,  Alberta...  440 

Radio  Specialties  (Ltd.),  Vancouver,  B.  C 450 

Laurentide  Air  Service,  Sudbury,  Ont 410 

Victoria  City  Temple.  Victoria,  British.  Col..  410 
The  Jack  Elliott  Radio  Limited.  Hamilton,  Ont.  410 

The  Radio  Shop,  London,  Ont 420 

Sparks  Co.,  Nariaimo,  B.  C 430 

Henry  Birks  &  Sons,  Calgary.  Alta 440 

Chas.  Guy  Hunter.  551  Adelaide  St.,  London. 

Ont 410 


Geared 
80tol 


CFRC 
CFUC 
CFXC 

ijFYC 
CHAC 
CHBC 
CHCB 
CHCD 
CHCE 

CHCL 

CHCM 
CHCS 
CHNC 
CHXC 
CHYC 
CJBC 
CJCA 
CJCC 
CJCD 
CJCE 
CJCF 
CJCI 

CJCK 
CJCM 
CJCN 
CISC 
CKAC 
CKCD 
CKCE 

CKCK 

CKCO 

CKCX 

CKLC 

CKOC 

CKY 

CNRC 

CNRE 

CNRM 

CNRO 

CNRR 

CNRS 

CNRT 

CNRW 


The  Electric  Shop  (Ltd.),  Saskatoon,  Saskatch- 
ewan    400 

Queens  University,  Kingston,  Ontario 4S0 

University  of  Montreal,  Montreal.  Quebec 400 

Westminster  Trust  Co.,  New  Westminster.  B. 

C 440 

Victor  Wentworth  Odium,  Vancouver,  B.  C 400 

Radio.Engineers.  Halifax,  Nova  Scotia 400 

Albertan  Publishing  Co..  Calgary,  Alberta 410 

Marconi  Company,  Toronto,  Ont 410 

Canadian  Wireless  &  Elec.  Co.,  Quebec,  Quebec  410 
Western   Canada   Radio  Sup.    (Ltd.).   Victoria. 

B.  C 400 

Vancouver    Merchants    Exchange.Vancouver, 

B.  C 440 

Riley  <fc  McCormack,  Calgary,  Alberta 415 

The  Hamilton  Spectator,  Hamilton,  Ont 420 

Toronto  Radio  Research,  Toronto,  Ont 350 

J.  R.  Booth,  Ottawa.  Ont 435 

Northern  Electric  Co.,  Montreal,  Quebec 410 

Jan-is  Baptist  Church,  Toronto,  Ont 312 

Edmonton  Journal,  Edmonton,  Alberta 455 

London  Free  Press  Prtg.  Co..  London,  Ont. 430 

T.  Eaton  Co..  Toronto,  Ont 410 

Sprott-Shaw  Radio  Co..  Vancouver,  B.  C 420 

The  News  Record.  Kitchener.  Ont 295 

Maritime  Radio  Corp.,  St.  John,  New  Bruns- 

wicE 400 

Radio  Corp.  of  Calgary.  Calgary,  Alta 316 

J.  L.  PhiUipe,  Monti  Joli,  Quebec 430 

Simons  Agnew  &  Co.,  Toronto.  Ont 410 

Evening  Telegram.  Toronto,  Ont 430 

La  Presse,  Pub.  Co.,  Montreal,  Quebec 430 

Vancouver  Daily  Province,  Vancouver,  B.  C. .  410 
Canadian  Independ.   Telephone  Co.,  Toronto, 

Ont 450 

Leader  Pub.  Co.,  Reeina.  Saskatchewan 420 

Ottawa  Radio  Association,  Ottawa,  Ont 440 

P-  Burns  &  Co..  Calgary,  AJberta 440 

Wilkinson  Electric  Company,  Calgary,  Algerta  400 
Wentworth  Radio  Supply  Co.,  Hamilton,  Ont.  410 
Manitoba  Telephone  System,  Winnipeg,  Man.  450 
Canadian  National  Railways,  Calgary,  Canada  440 
Canadian  National  Railways,  Edmonton,  Alta.  450 
Canadian  National  Railways,  Montreal.  P.  Q.  341 
Canadian  National  Railways,  Ottawa,  Ont..  .  435 
Canadian  National  Railways,  Regina,  Sask. .  .  420 
Canadian  National  Railways,  Saksatoon,  Sask.  400 
Canadian  National  Railways.  Toronto,  Ont..  400 
Canadian  National  Railways,  Winnipeg.  Man.  .  450 


New  Straight-line  Condensers 
The  Ensign  variable  straight-line  wave- 
length condenser  is  one  of  the  most  ad- 
vanced straight  line  condensers  that  has 
as  yet  been  placed  on  the  market.  By 
means  of  the  peculiar  type  construction 
of  both  the  stationary  and  movable  plates, 
it  is  possible  to  secure  a  straight-line  wave- 
length curve  over  the  entire  range  from 
minimum  to  maximum. 


on 


dot 


It's  as  easy  as  P* otl  a 

\,*r    pencil   Poin5^.this 
yo    „  on  the  maf  Tj  5? 

tutuog.1? 

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76  RADIO  AGE  for  February,  1925 

WCBA-     Charles  W.  Heimbach . .       Allentown,  Pa.  280  WJAN 

WCEC     University  of  Michigan Ann  Arbor,  Mich.  280  WJAR 

WCBD      Wilbur  G.  Voliva Zion,  111.  345  WJAS 

WCBE       Uhalt  Radio  Co New  Orleans.  La.  263  WJAX 

WCBF      Paul  J.  Miller Pittsburgh,  Pa.  236  WJAZ 

WCBG      Howard  S.  Williams  (Portable) Pascagoula,  Miss.  268  WJD 

WCBH      University     of     Miss Oxford,     Miss.  242  WJJD 

WCBI       Nicoll,  Duncan  &  Rush Bemis,  Tennessee  240  WJY 

WCBJ       J.  C.  Maus Jennings,  Louisiana  244  WJZ 

WCBK     E.    Richard  Hall St.  Petersburg,  Fla.  266  WKAA 

WCBL       Northern   Radio  Mfg.  Co Houlton,  Me.  280  WKAD 

WCBM     Charles  Swarz Baltimore.  Md.  229  WKAF 

WCBN      James  P.  Boland Ft.  Benj.  Harrison,  Ind.  266  WKAN 

WCBO      The  Radio  Shop,  Inc Memphis,  Tenn.  250  WK.AP 

WCBQ      First   Baptist    Church Nashville,   Tenn.  236  WKAQ 

WCBR      C.  H.  Mes.ter Providence.   R.  I.  246  WKAR 

WCBT       Clark  University,  Collegia!*  Dept Worcester,  Mass.  238  WKAV 

WCBU      Arnold  Wireless  Supply  Co Arnold,  Pa.  254  WKBF 

WCBV      Tullahoma  Radio  Ctub Tullahoma,  Tenn.  252  WKY  \ 

WCBW     George  P.  Rankin,  Jr..  and  Maitland  Solomon Macon,  Ga.  226  WLAG 

WCBX      Radio  Shop  of  Newark  (Herman  Lubiusky) Newark,  N.  J.  233  WLAL 

WCBY      The  Forks  Electrical  Shop Buck  Hill  Falls,  Pa.  268  WLAP 

WCBZ       Coppotelli  Bros.  Music  House Chicago  Heights,  111.  248  WLAQ 

WCCO       Washburn-Crosbv    Co Twin    Cities.    Minn.  417  WLAW 

WCEE      Charles  E.  Erbstein,  Villa  Olivia near  Elgin,  III.  536  WLAX 

WCK        Stix-Baer-Fuller  D.  G.  Co St.  Louis,  Mo.  275  WLB 

WCX  Free     Press Detroit,     Mich.  517  WLBL 

WDAE      Tampa  Daily  Times Tampa,  Fla.  360  WLS 

WDAF       Kansas   City   Star Kansas   City,    Mo.  411  WLW 

WDAG      J.    Laurence  Martin Amarillo.  Tex.  263  WMAC 

WDAH      Trinity  Methodist  Church   (South) El  Paso,  Tex.  268  WMAF 

WDAR      Lit     Brothers Philadelphia,     Pa.  395  WMAH 

WDAS       Samuel   A.    Waite Worcester,    Mass.  360  WMAK 

WDA Y      Radio   Equipment   Corp Fargo,    N.    Dak.  244  WMAL 

WDBA      Fred     Ray Columbus,     Ga.  236  WMAN 

WDBB      A.  H.  Waite  &  Co.,  Ino Taunton,  Mass.  229  WMAQ 

WDBC       Kirk,    Johnson    &    Co Lancaster,    Pa.  258  WMAV 

WDBD      Herman     Edwin     Burns Martinsburg.     W.     Va.  268  WMAY 

WDBF       Robert  G.  Phillips Youngstown,  Ohio  246  WMAZ 

WDBH      C.  T.  Scherer  Co Worcester,  Mass.  268  WMC 

WDBI        Radio  Specialty  Co St.   Petersburg,  Fla.  226  WMU 

WDBJ       Richardson    Wayland    Electrio    Corp Roanoke,    Va.  229  WNAC 

WDBL       Wise.  Dept.  of  Markets Stevens  Point,  Wis.  278  WNAD 

WDBN      Electric  Lipht  &  Power  Co Bangor,  Me.  252  WNAL 

WDBO      Rollins     College    Inc Winter    Park.     Fla.  240  WNAP 

WDBP       Superior   State   Normal   School Superior,   Wis.  261  WNAR 

WDBQ      Morton   Radio  Supply  Co Salem,   N.   J.  234  WNAT 

WDBR      Tremont  Temple  Baptist  Church Boston,  Mass.  256  WNAX 

WDBS      S.  M.  K.  Radio  Corp Dayton.  Ohio  283  WN YC 

WDBT      Taylor's  Book  Store Hattiesburg,  Miss.  236  WOAC 

WDBV      The  Strand  Theatre Fort  Wayne,  Ind.  258  WOAE 

WDBW     The  Radio  Den Columbia.  Tenn.  268  WOAF 

WDBX      Otto  Baur New  York.  N.  Y.  233  WOAG 

WDBY      North    Shore    Congregational    Church Chicago.    Ilf.  258  WOAI 

WDBZ       Boy  Scouts,   City  Hall Kingstown,  N.  Y.  233  WOAN 

WDM         Church   of   the   Covenant Washington.    D.   C.  234  WOAO 

WDZI        J.  L.  Bush Tuscola.  111.  278  WOAR 

WEAA       F.  D.  F.illain Flint.  Mich.  250  WOAT 

WEAF       American  Telephone  &  Telegraph  Co New  York,  N.  Y.  492  WOAV 

WEAH      Wichita  Board  of  Trade Wichita,  Kans.  280  WOAW 

WEAI        Cornell  University Ithaca,  N.  Y.  286  WOAX 

WEAJ        University  of  South  Dakota Vermilion.  S.  Dak.  283  WOC 

WEAM  Borough  of  North  Plainiiekl  (W.  Gibson  Buttfield) .  .  .North  Plainfield,  N.  J  286  WOI 

WEAN       Shepard    Co Providence,    R.    I.  273     ,    WOO 

WEAO       Ohio  State  University Columbus,  Ohio  360  WOR 

WEAP       Mobile   Radio   Co Mobile,  Ala.  263  WOS 

WEAU      Davidson  Bros.  Co Sioux  City,  Iowa  275  WPAB 

WEAY       Iris  Theatre   (Will  Horowitz,  Jr.) Houston.  Texas  360  WPAC 

WEB  Benwool    Co St.    Louis,    Mo.  273  WPAJ 

WEBA       Electric  Shop Highland  Park,  N.  J.  233  WPAK 

WEBC       Walter    Cecil    Bridges Superior,    Wis.  242  WPAL 

WEBD       Electrical  Equipment  and  Service  Co Anderson,  Ind.  246  WPAR 

WEBE       Roy  W.    Walker Cambridge,  Ohio  248  WPAU 

WEBH       Edgewater  Beach   Broadcasting  Station Chicago,   111.  370  WPAZ 

WEB1         Walter   H.  Gibbons Salisbury,   Md.  242  WPG 

WEB  J        Third  Avenue  Railway  Co New  York,  N.  Y.  273  WQAA 

WEBP      "E.   B.   Pedicord New   Orleans,   La.  280  WQAC 

WEBT      'The  Dayton  Coop.  Industrial  High  School Dayton,  Ohio  270  WQAE 

WEBU       DeLand  Piano  &  Music  Co.,  139  Boulevard  St DeLand.    Fla.  258  WQAF 

WEBW       Beloit  College Beloit,  Wise.  283  WQAM 

WEBX       John   E.   Cain.  Jr Nashville,   Tenn.  263  WQAN 

WEBY      Hobart     Radio     Co Roalindale,      Mass.  226  WQAO 

WEEI         The  Edison  Electric  Illuminating  Co Boston.  Mass.  303  WQAQ 

WEV  Hulbert-Still    Elec.    Co Houston,    Tex.  263  WQAS 

WEW         St.    Louis    University St.     Louis.     Mo.  280  WQAX 

WFAA       Dallas  News  &  Dallas  Journal Dallas.  Texas  476  WQJ 

WFAM      Times  Publishing  Co St.  Cloud,  Minn.  273  WRAA 

WFAN       Hutchinson  Electric  Service  Co Hutchinson,  Minn.  286  WRAF 

WFAV  University  of  Nebraska.  Department  of  Electrical  Engineering . .  Lincoln,  Nebr.  275  WR  AL 

WFBB       Eureka  College Eureka,  111.  240  WRAM 

WFBC       First  Bap.ist  Church Knoxville,  Tenn.  250  WRAN 

WFBD       Gethsemane    Baptist    Church Philadelphia,    Pa.  234  WRAO 

WFBE       John  Van  De  Walle Seymour,  Ind.  226  WRAV 

WFBG      The  Wm.  F.  Cable  Co Altoona,  Pa.  261  WRAW 

WFBH      Concourse  Radio  Corporation New  York.  N.  Y.  273  WRAX 

WFBJ        St.  John's  University Collegeville.   Minn.  236  WRBC 

WFBQ      Wynne  Radio  Co Raleigh,  N.  C.  255  WRC 

WFBR       Fifth  Inf.  Md.  Nat'l  Guard,  5th  Reg.  Armory Baltimore.^Md.  452  WREO 

WFBT       Gloucester  Co.  Civic  League Pitman,  N.  J.  231  WRHF 

WFBW      Ainsworth-Gates       Radio      Co Cincinnati,  Ohio  309  WRK 

WFBY       Signal  Officer Ft.  Ben  Harrison,  Ind.  258  WRL 

WFBZ       Knox   College Galesburg,   111.  254  WRM 

WFI  Strawbridge  and  Clothier ...Philadelphia,  Pa.  395  WRR 

WGAL      Lancaster  Electrio  Supply  &  Construction  Co Lancaster,  Pa.  248  WRW 

WGAQ      Youree  Hotel Shreveport,  La.  252  WSAB 

WGAZ      South  Bend  Tribune \ South  Bend.  Ind.  360  WSAC 

WGBB      Harry  H.  Carman,,  217  Bedell  St Freeport,  N.  Y.  244  WSAD 

WGBC      First  Baptist  Church Memphis,  Tenn.  266  WSAI 

WGBS       Gimbel  Brothers New  York,  N.  Y.  316  WSAJ 

WGBT      Furman     University Greenville,     S.    C.  236  WSAN 

WGI  American  R.  &  R.  Co Medford  Hillside,  Mass.  360  WSAP 

WGL  Thos.   F.   J.   Howlett Philadelphia,   Pa.  360  WSAR 

WGN  The    Tribune    Co Chicago,     111.  370  WSAU 

WGR  Federal  T.  and  T.  Co Buffalo,  N.  Y.  319  WSAV 

WGY         General  Elec.  Co Schenectady,  N.  Y.  380  WSAY 

WHA  University    of    Wisconsin Madison,    Wis.  275  WSAZ 

WHAA      State  University  of  Iowa Iowa  City,  Iowa  484  WSB       ~~ 

WHAD      Marquette  University Milwaukee,  Wis.  280  WSL 

WHAG      University  of  Cincinnati Cincinnati.  Ohio  222  WSOE 

WHAH      Hafer  Supply   Co Joplin.    Mo.  283  WTAB 

WHAM     University  of  Rochester  (Eastman  School  of  Musio) Rochester.  N.  Y.  283  WTAC 

WHAR      Seasidellouse Atlantic  City.  N.  J.  275  WTAF 

WHAS      Courier-Journal  &  Louisville  Times Louisville.  Ky.  400  WTAL 

WHAV      Wilmington  Electrical  Specialty  Co Wilmington.  Del.  360  WTAM 

WHAZ      Rensselaer  Polytechnic  Institute Troy.  N.  Y.  380  WTAP 

WHB  Sweeney  School  Co Kansas  City,  Mo.  411  WTAQ 

WHK         Radiovox     Company Cleveland,     Ohio  283  WTAR 

WHN  George    Sehubel New    York,    N.    Y.  360  WTAS 

WHO  Bankers    Life    Co Des    Moines,    la.  526  WTAT 

WIAB        Joslyn  Automobile  Co Rockford,  111.  252  WTAU 

WIAC        Galveston  Tribune Galveston,  Texas  360  WTAW 

W1AD        Howard   R.  Miller Philadelphia,  Pa.  254  WTAX 

WIAK       Journal-Stockman   Co Omaha,  Nebr.  278  WTA Y 

WtAQ       Chronicle   Publishing   Co Marion,    Ind.  226  WTAZ 

WI AS        Home  Electric  Co Burlington.  Iowa  283  WTG1 

WIK.  K.    &    L.    Co McKeesport,     Pa.  234  WTX 

WIL  Continental    Electrio    Supply    Co Washington.    D.     C.  3S0  WWAD 

WIP  Gimbel  Bros Philadelphia,  Pa.  509  WWAE 

WJAB       American  Electric  Co Lincoln.  Neb.  229  wwi 

WJAD       Jackson's  Radio  Engineering  Laboratories Waco,  Texas  353  .,,„,, 

WJAG      Norfolk  Daily  News Norfolk.  Nebr.  283  WWJ 

WJAK      Clifford  L.  White Greentown,  la.  254  WWL 

WJAM      D.  M.  Perham Cedar  Rapids,  Iowa  268  WWOA 


The  Magazine  of  the  Hour 


Peoria    Star Peoria,    111.  280 

The  Outi    i  Co.  (J.  Samuels  <fe  Bro.) Providence,  R.  I.  360 

Pittsburgh  Radio  Supply  House Pittsburgh.  Pa.  286 

Union  Trust  Co Cleveland,  Ohio  390 

Chicago  Radio    Laboratory Chicago,  III,  268 

Denison  University Grantvilie,  Ohio  229 

Supreme  Lodge,  Loyal  Order  of  Moose Mooseheart,    HI.  278 

Radio  Corp.  of  Ama New  York,  N.  Y.  405 

Radio  Corp.  of  Ama New  York,  N.  Y.  455 

H.  F.  Paar ,  Cedar  Rapids,  Ibwa  278 

Cbas.  Looff  (Crescent  Park) East  Providence,  R.  I.  240 

W.  S.  Radio  Supply  Co Wichita  Falla,  Texas  360 

United  Battery  Service  Co Montgomery,  Ala.  226 

Dutee  W.  Flint Cranston,  R.  I.  360 

Radio  Corp.  of  Porto  Rico San  Juan,  P.  R.  360 

Michigan  Agriculture  College East  Lansing,  Mich.  280 

Laconia  Radio  Club Laconia,  N.  H.  254 

Dutee  Wilcox  Flint .Cransten,  Rhode  Island  286 

Wky  Radio  shop Okla  City,    Okla.  360 

Cutting  &  Washington  Radio  Corp Minneapolis,  Minn.  417 

Naylor  Electrical  Co Tulsa,  Okla.  360 

Wm.  V.  Jordan Louisville,  Ky.  286 

Arthur  E,  Shilling Kalamazoo,  Mich.  283 

Police  Dept.,  City  of  New  York New  York,  N.  Y.  360 

Putnam  Electric  Co Greencastle,  Ind.  231 

University   of   Minnesota Minneapols,   Minn.  278 

Wisconsin  State  Dept.  of  Markets Stevenspoint,  Wis.  278 

Sears    Roebuck    &    Co Chicago,    111.  345 

Crosley  Mfg.  Co Cincinnati,  Ohio  423 

J.  Edw.  Page  (Olive  B.  Meredith) Cazenovia,  N.  Y.  261 

Round  Hills  Radio  Corp Dartmouth,  Mass.  360 

General  Supply  Co Lincoln,  Nebr.  254 

Norton  Laboratories Loekport,  N.  Y.  273 

Trenton  Hardware  Co Trenton,  N.  J.  256 

First  Baptist  Church Columbus,  Ohio  286 

Chicago  Daily  News Chicago.  111.  448 

Alabama   Polytechnic   Institute Auburn,   Ala.  250 

Kingshighway  Presbyterian  Church St.  Louis,  Mo.  280 

Mercer  University Macon,  Ga.  261 

Commercial     Appeal Memphis,  Tenn.  500 

Doubledal-Hill  Elec.  Co Washington,   D.  C.  261 

Shepard  Stores Boston,  Mass.  278 

University  of  Oklahoma Norman,  Okla.  254 

Omaha  Central  High  School Omaha.  Nebr.  258 

Wittenberg  College Springfield,  Ohio  275 

First  Christian  Church Butler,  Mo.  231 

Lennig  Brothers  Co.  (Frederick  Lennig) Philadelphia,  Pa.  250 

Dakota  Radio  Apparatus  Co Yankton,   S.  Dak.  244 

Dept.  of  Plant  and  Structures New  York,  N.  Y.  520 

Page  Organ  Co lama,  Ohio  266 

Midland  College Fremont,  Nebr.  280 

Tyler    Commercial   College Tyler,   Texas  360 

Apollo  Theater  (Belvidere  Amusement  Co.) Belvidere,  111.  273 

Southern  Equipment  Co San  Antonio,  Texas  385 

Vaughn  Conservatory  of  Musio  (James  D.  Vaughn) . . .  .Lawrenceburg,  Tenn.  360 

Lyradion  Mfg.  Co Mishawaka,  Ind.  360 

Lundskow,  Henry  P Kenosha,  Wis.  229 

Boyd  M.  Hamp Wilmington,  Del.  360 

Pennsylvania  National  Guard.  2d  Battalion,  112th  Infantry Erie,  Pa.  242 

Woodmen  of  the  World Omaha,  Nebr.  526 

Franklyn  J.  Wolff Trenton,  N.  J.  240 

Palmer    School    of    Chiropractio Davenport,  la.  484 

Iowa  State  College Ames,  la.  360 

John  Wanamaker Philadelphia,  Pa.  509 

L.   Bamberger  and   Co Newark,  N.  J.  405 

State    Marketing    Bureau Jefferson  City,  Mo.  441 

Pennsylvania  State  College State  College.  Pa.  283 

Donaldson  Radio  Co Okmulgee,  Okla.  360 

Doolittle  Radio  Corp New  Haven,  Conn.  268 

North  Dakota  Agricultural  College Agricultural  College,  N.  D.  283 

Superior  Radio  &  Telephone  Equipment  Co Columbus,  Ohio  286 

Ward  Battery  and  RadioCo Beloit,  Kans.  236 

Concordia  College Moorhead,   Minn.  286 

John  R.  Koch  (Dr.) Charleston,  W.  Va.  273 

The  Municipality  of  Atlantic  City Atlantic  City,  N.  J.  296 

Horace  A.  Beale,  Jr Parkersburg,  Pa.  270 

E.  B.  Gish Amarillo,  Texas  234 

Moore  Radio  News  Station  (Edmund  B.  Moore) Springfield,  Vt.  275 

Sandusky   Register Sandusky,  Ohio  240 

Electrical     Equipment     Co Miami,     Fla.  283 

Scranton  Times Scranton.  Pa.  280 

Calvary  Baptist  Church New  York,  N.  Y.  360 

Abilene  Daily  Reporter  (West  Texas  Radio  Co.) Abilene,  Texas  360 

Prince-Walter  Co Lowell,  Mass.  266 

Radio  Equipment  Company Peoria,  111.  248 

Calumet  Rainbo  Broadcasting  Co Chicago,  111.  448 

The  Rice  Institute Houston,  Tex.  256 

The  Radio  Club  (Inc.) Laporte,  Ind.  224 

Northern  States  Power  Co St.  Croix  Falls.  Wis.  248 

Lombard  College Galesburg,  111.  244 

Black  Hawk  Electrical  Co Waterloo,  Iowa  236 

St.  Louis  Radio  Service  Co St.  Louis,  Mo.  263 

Antioch  College Yellow  Springs,  Ohio  242 

Avenue  Radio  Shop  (Horace  D.  Good) Reading,  Pa.  238 

Flaxon'a  Garage Gloucester  City,  N.  J.  268 

Imanuel  Lutheran  Church Valparaiso,  Ind.  278 

Radio  Corp.  of  Ama Washington,    D.  C.  469 

Reo  Motor  Car  Co. .' Lansing,  Mich.  288 

Washington   Radio   Hospital Washington.   D.   C.  256 

Doron  Bros Hamilton,  Ohio  360 

Union  College Schenectady,    N.  Y.  270 

University   of  Illinois Urbana,   111.  273 

Police  and  Fire  Signal  Department Dallas,    Tex.  261 

Tarrytown   Radio   Res.  Labs Tarrytown,     N.  Y.  273 

Southeast  Missouri  State  Teachers  College Cape  Girardeau,  Mo.  275 

Clemson  Agricultural  College Clemson  College,  S.  C.  360 

J.  A.  Foster  Co Providence,  R.  I.  261 

United  States  Playing  Cards  Co Cincinnati.  Ohio  309 

Grove  City  College Grove  City,  Pa.  258 

Allentown    Call    Publishing    Co Allentown,    Pa.  229 

Seventh  Day  Adventist  Church New  York,  N.  Y.  263 

Doughty  &  Welch  Electrical  Co Fall  River,  Mass.  254 

Camp  Marienfeld Chesham,  N.  H.  229 

C.  W.   Vick   Radio  Construction   Co Houston,  Tex.  360 

Irving  Austin  (Port  Chester  Chamber  of  Commerce).  .Port  Chester,  N.  Y.  233 

Chas.  Electric  Shop Pomeroy ,  Ohio  258 

Atlanta  Journal Atlanta ,    Ga.  429 

J.  and  M.  Elec.  Co.. Utica,  N.  Y.  273 

School    of   Engineering, Milwaukee,     Wis.  246 

Fall  River  Daily  Herald  Publishing  Co Fall  River,  Mass.  248 

Penn  Traffic  Co Johnstown,  Pa.  360 

Louis  J.  Gallo New  Orleans,  La.  242 

Toledo  Radio  &  Electrio  Co Toledo,  Ohio  252 

Willard  Storage  Battery  Co Cleveland,  Ohio  390 

Cambridge  Radio  &  Electric  Co Cambridge.  111.  242 

S.  H.  Van  Gordon   &  Son Osseo,  Wis.  220 

Reliance   Eectrio   Co Norfolk,  Va.  280 

Charles  E.  Erbstein Elgin,  111.  286 

Edison  Electrio  Illuminating  Co Boston,  Mass.  (portable)  244 

Ruegg  Battery  &  Electric  Co Tecumseh,  Nebr.  242 

Agricultural  &  Mechanical  College  of  Texas College  Station,  Tex  280 

Williams   Hardware   Co Streator,  'Til.  231 

Oak  Leaves  Broadcasting  Station Oak  Park,  111.  283 

Thomas  J.   McGuire Lambertville.    N.   J.  283 

Kansas  State  AgriculturalCollege Manhattan,  Kans.  273 

H.  G.  Saal  Co Chicago,  111.  268 

Wright  &  Wright  (Inc.) Philadelphia.  Pa.  360 

The  Alamo  Ball  Room Joliet,  111.  242 

Ford  Motor  Co Dearborn,  Mich.  273 

Detroit  News  (Evening  News  Assn.) Detroit,  Mich.  517 

Loyola  University New    Orleans ,  La.  260 

Michigan  College    of  Mines Houghton,  Mich.  244 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


77 


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LISTEN  TO  RADIO  AGE 

From  KYW 


"Up  the  Ladder"  With 
The  Beginner 

(Continued  from  page  27) 
circuit  diagrams  show  the  proper  hookup. 
Note  that  there  is  no  connection  from  the 
primary  to  the  secondary. 
Amplification 
i~  UDIO  amplification  consists  of  ampli- 
■^*-  fying   the    low    frequency    currents. 
The  method  employed  consists  essentially 
of  a  series  of  audion  amplifiers  arranged 
electrically  so  that  the  amplified  output 
of  each  tube  is  passed  on  successively  to 
the  next,  to  be  amplified  again.      Each 
tube    with    its    passing-on    coupling    is 
referred  to  as  a  stage,  or  "step"  in  the 
amplifier. 

As  magnification  of  tube  and  battery 
noises  and  other  disturbances  of  this 
nature  are  proportional  to  the  magnifica- 
tion of  the  signal  received,  the  number 
of  audio  frequency  stages  which  are 
advisable  is  two,  possibly  three. 

Several  methods  of  linking  tubes  -are 
possible;  for  instance,  resistance,  induc- 
tance or  transformer  coupling.  The 
latter  method  is  by  far  the  most  popular, 
although  the  resistance  coupled  amplifier 
is  rapidly  gaining  great  favor,  where 
volume  is  a  second  consideration. 


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We  can  save  you  money  no  matter  how  large  or 
small  a  set  you  intend  to  buy. 

G.-P.  Co.,  Box  T,  Colfax,  Iowa. 


Prices  Smashed! 

Quality  Not  Sacrificed 


Here  is  real  battery 
quality,  guaranteed   to   you,  at 
prices  that  will  astound  the  en- 
tire battery-buying  public.  Order 
direct  from  factory.  Put  the  Dealer's 
Profit  in  your  own  pocket.  You  actually  save 
much  more  than  half,  and  so  that  you  can  be 
convinced  of  true  quality  and  performance,  we 

give  a  Written  Two-Year  Guarantee 

Hereisyourprotection!Noneedtotakeachance. 
Ourbatteryis  right—  and  the  price  is  the  lowest 
evermade.  Convince  yourself.  Read  the  prices! 
Special  2-Volt  Radio  Storage  Battery,       £3.75 
Special  4-Volt  Radio  Storage  Battery,        6.00 
6-Volt,  GO  Amp.  Radio  Storage  Battery.     7.00 
6-Volt,  80  Amp.  Radio  Storage  Battery,     8.00 
6-Volt,  100  Amp.  Radio  Storage  Battery,  9. SO 
6-Volt,  120  Amp.  Radio  Storage  Battery,  1  l.SO 
6-Volt,  140  Amp.  Radio  Storage  Battery,  13. OO 

We  ask  for  no  deposit.  Simply  send  name 
and  address  and  style  wanted.  Battery  will 
be  shipped  the  day  we  receive  your  order 
Express  C.  O.  D.,  subject  to  your 
examination  on  arrival.  Our         ^^^U, 
guarantee   accompanies 
each  battery.  We  allow  5% 
discount  for  cash  in  full 
with  order.    You  cannot 
lose!  Act  quick.  Send  your 
order  today— NOW. 


Arrow  Battery  Co. 

1215  South  Wabash  Ave. 
DepL  1  Chicago,  III. 


SEND  NO  MONEY! 

=aYour  OWN  Name  and  Address 
ID  Printed  Free'ion  Thank  You  Cards 

what  YOU  lite.  Stations  glad- 
.  ,  _j  on  numbers  at  your  request. 
Thank  your  favorite  stations.  Spe- 
k-liU  cards  that  set  ATTENTION. 
All  the  RAGE.  100— S1.00;  200— 
\  i\  1. 1»:  :;n'i  .vj. oil;  r.mi  -?.:;. uo:  looo— 
H5.00.    Postpaid  if  pay  with  order. 

(MONEY  REFUNDED  If  Not  Delighted 

^Quality  cards.  High  grade  printing. 
Send  no  money— just  jtav  jMstmanwfwnyau  get  eards.Order  JVO  Wt 

I     RADIO  PRINTERS,    2022  M«inSt,Mendota,Ul. 


DEVICES 

displaying  this  seal 
have  been  tested 
and  approved  by 
the  RADIO  AGE 
INSTITUTE. 

The  apparatus  illus- 
t  r  a  t  e  d  and  des- 
cribed below  have 
successfully  passed 
our  tests  for  Feb- 
ruary, 1925. 


Radio  Age  Institute 

Manufacturers'  Testing  Service 

KjEMBERS  of  the  staff  of  RADIO  AGE  will  be  pleased  to  test  devices 
■";*■  and  materials  for  radio  manufacturers  with  the  object  of  deter- 
mining their  efficiency  and  worth.  All  apparatus  which  meets  with 
the  approval  of  various  tests  imposed  by  members  of  the  technical 
staff  of  RADIO  AGE  will  be  awarded  our  endorsement,  and  the  seal 
shown  to  the  left  will  be  furnished  free  of  charge.  Materials  for 
testing  should  be  sent  to 

RADIO  AGE  INSTITUTE 

504  N/Dearborn  Street,  Chicago,  111. 


Test  No.  30. 
F  E  D  E  R  A  L 
TYPE  201-A 
VACUUM 
TUBE.  This  tube 
was  submitted 
for  test  by  the 
Service  Lamp 
Co.,  112-114 
Trinity  Place, 
New  York  City, 
N.Y.  Due  to  the 
efficient  manner 
in  which  the  tube 
is  packed,  it  ar- 
rived in  good  con- 
dition. Although 
no  tests  were 
made  to  deter- 
mine the  life  of 
the  tube,  it  gave 
very  good  re- 
sults. It  is  well  manufactured 
according  to  all  the  latest  practices 
and  gave  excellent  results  as  a 
detector  amplifier  and  oscillator. 
The  filament  consumption  at  five 
volts  was  one  quarter  ampere  and 
ninety  to  one  hundred  and  twenty 
volts  can  safely  be  used  on  the 
plate.  Tested  and  approved  by 
RADIO  AGE  Institute. 


Test  No.  31.  THE  DAVEN 
SUPER-AMPLIFIER.  The  Daven 
Radio  Corporation  of  Newark, 
N.  J.,  submits  one  of  their 
super-amplifiers  for  testing  pur- 
poses. We  have  found  by  actual 
experience  that  the  tone  quality 
of  this  amplifier  far  surpasses  any 
other  method  of  amplification  that 
is  now  practiced.  Tube  noises 
were  eliminated  to  a  very  great 
extent;  in  fact  they  were  negligible. 
Its  consumption  of  "B"  battery 
current  was  less  than  half  of  the 
amount  consumed  by  ampli- 
fiers of  the  ordinary  type.  The 
amplifier  is  delivered  all  wired  and 
ready  to  install  in  the  set.  Arrived 
in  excellent  condition,  and  passed 
the  tests  and  requirements  of 
RADIO  AGE  Institute. 


Test  No.  32.  THE  MUSSEL- 
MAN  SELECTIVE  ANTENNA. 
Submitted  by  the  Cycle  Mfg. 
&  Supply  Co.,  Chicago,  111. 
This  type  of  antenna  wire  is 
a  radical  departure  from  the  usual 
type  of  wire  used  in  antenna  con- 
struction. It  is  constructed  with  a 
center  core  made  of  solid  copper 
of  4200  circular  mills  capacity; 
over  this  a  1-32  inch  rubber  insula- 
tion of  high  quality;  over  the  whole 
is  an  outer  cover  of  braided  copper 
wire,  tinned  to  prevent  corrosion, 
with  a  capacity  of  4800  circular 
mills.  When  this  wire  is  used  as  a 
straight  aerial  and  not  as  a  loop, 
the  outside  copper  tinned  braid, 
because  of  its  surface,  acts  as  an 
ideal  wave  collector.  Arrived  in 
good  condition,  and  satisfactorily 
passed  the  tests  and  requirements 
of  RADIO  AGE  Institute. 


Test  No.  33.  BREMER  TULLY 
LOW  LOSS  CONDENSER.  Sent 
to  us  for  test  by  the  Bremer  Tully 
Mfg.  Co.,  531  So.  Canal  St., 
Chicago,  111.  After  many  tests  we 
have  found  this  condenser  to  be 
truly  of  the  low  loss  type.  When 
tested  on  laboratory  instruments, 
it  was  practically  impossible  to 
measure  any  losses.  The  style  of 
construction  is  rugged  and  depend- 
able. The  manner  in  which  the 
rotor  plates  are  assembled  pro- 
hibits of  high  resistance  leaks. 
Satisfactorily  passed  the  require- 
ments of  RADIO  AGE  Institute. 


#     Tested  and  Approved  by  RADIO  AGE     * 


78 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


RADIO'S    WONDER    CIRCUIT! 
4  Tubes  Do  the  Work  of  7  in  the 

Telmaco  P-l  Receiver 

Coast  to  coast  reception.  Aerial,  loud 
speaker  and  batteries  self-contained. 
Carry  from  room  to  room — take  it  any- 
where. Ask  your  dealer  or  write  us.  Free 
descriptive  folder. 

Radio  Division 

TELEPHONE  MAINTENANCE  CO. 

20  S.  Wells  Street,  Dept.  C,         Chicago,  111. 

Quality  Radio  Exclusively  Since  1918 


I  Make  the  Best  CHOCOLATE  BARS 

Mints  and  Chewing  Gum.     Be  my  agent.     Every- 
body will  buy  from  you.  Write  today.  Free  Samples. 
MILTON  GORDON,  576  Jackson  St.,  Cincinnati,  Ohio 


%°££r*fe 


MICA  CONDENSER 

Patent  Pending 
insure  high  efficiency  and  the 
Build-Up  feature  enables 
the  operator  to  obtain  any 
definite  capacity  from  .0005 
to  .006  by  simply  adding 
extra  plates  of  copper  and 
mica  to  the  Build-Up  base. 

Each  alternate  copper  and  mica  plate  has  a 
capacity  of  approximately  .0002  Mfd. 

Build-Up  Mica  Condensers  of  the  following 
capacities,  each  assembled  complete  in  carton, 
at  the  following  prices: 

.00025  Mfd.„ .List  price  50c 

.0005   "  

.001     "  

.002    "  

.0025    "  

.005     " 

.006     "  


50c 
55c 
60c 
65c 
70c 
75c 

Extra  envelope  containing  20  copper  and 
mica  plates,  or  sufficient  to  build  up  a  con- 
denser from  .00025  to  .006,  list  price  25c. 

Table  showing  required  number  of  plates 
needed  for  any  capacity  is  furnished  with 
each  condenser. 

Ask  your  dealer — or  order  direct 

CHAS.  SCHINDLER 


1404  W.  Delaware  Ave., 


Toledo,  Ohio 


SPECIAL 

INTRODUCTORY  PRICE 

For  a  limited  time  only,  and  to  introduce  this 
new  and  superior  Storage  "B"  Radio  Battery  to 
the  Public,  we  are  selling  it  for  $3.30.  Regular 
Retail  Price  is$5.50.  Yousave  $2.00  by  ordering 
NOW.  A  finer  battery  cannot  be  built  than  the 

World  Storage  "B"  Battery 

(12  CELLS-24  VOLTS) 
To  ten  million  homes  with  Radio  Rets -and I  to  countless  mil- 
lions  of 'prospective  buyera-this  WORLD  Stores*  ■'B'*.  Bat- 
tery brings  a  new  conception  of  battel  y  economy 'and  Perform- 
ance  Here  is  a  battery  that  pays  for  itself  m  a  few  weeks- 
will  last  for  years  and  can  bo  recharged  at  a  negligible  coal. 
And  you  save  $2.00  bv  ordering  now. 
a    n  •        t»     *.*.  Equipped  With 

A  Superior  Battery  solid  Rubber  case 

Has  heavy  duty  2  1-8  in.  x  1  in.  x  1-4  In.  plates  and  plenty  of 
Bcid  circulation.  Extra  heavy  glass  jars  allow  ready  observa- 
tion of  charge  and  prevent  k-akage  and  seepage  or 
It  holds  its  chance,  while  idk-,  at  constant  voltage. 
You  will  find  this  battery  a  boon  t"  '- 
It  does  away  with  a  great  many  r. 
"'static."  Mail  your  order  today. 

SEND  NO  MONEY 

Jast  state  number  of  batteries  wanted  and  we  will  shlo  daj 
order  .3  received.  EXTRA  OFFER:  4  batteries  In  series  OS 
volt<ii  til  00  Pay  Expressman  alter  examining  batteries.  I» 
per  rent  Jisc'onnt  for  cash  In  full  with  order.  Send  your  or** 
WOW  and  save  S2.00. 

WORLD  BATTERY  COMPANY 

■I        Makers  of  the  famous  World  Radio  "A'*  Storage  Batterg 

"«    1219  S.  Wabash  Ave.,  Dept.  81  Chicago,  111. 

SAVE  $2.00  BY  ORDERING  NOW! 


THE  RADIO  AGE  BUYERS'  SERVICE 


What  do  you  want  to  purchase  in  the  radio  line?     Let  the  staff  of  RADIO   AGE   save 
Enter  the  number  of  the  article  you  would  like  to  know  more  about  in  the  spaces  provided  in 


1  "A" 

2  Aeri 

3  Aeri 

4  Aeri 

5  Ae 

6  An 

7  An 

8  An 


Batteries 
si  protectors 
al  insulators 
lis 

,ls 


■s,  lo 


olded 


oltage) 


nplifiers 
nplifying  units 
..meters 
9  "B"  batteries 

10  Batteries  (state  1 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plateB 

16  Battery  substitutes 

17  Bezels 

18  Binding  posts 

19  Binding  posts,  insulated 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatstone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisers 

33  Coils 

34  Coils,  choke 

35  Coils,  coupling 

36  Coils,  Biter 

37  Coils,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance, 

40  Coils,  Reinartz 

41  Coils,  stabilizer 

42  Coils,  tuning 

43  Condenser  parts 

44  Condenser  plates 

45  Condensers,  antenna  COU{ 
ling 

46  Co  i 

47  Co. 

48  Conn. 

49  Cond 
„     grid,, 

50  Cond, 

51  Condensers,  va 

52  Condensers,  vei 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  sets 


sers,  fixed  (paper, 

phone) 

sers,  variable  grid 

sers,  variable  mica 


57  Coupler! 

58  Coupler; 

59  Coupler: 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 

71  Dial,  adjusters 

72  Dials,  composition 

73  Dials,  hard  rubber 

74  Dials,  rheostat 

75  Dials,  metal 

76  Dials,  vernier 

77  Dials  with  knobs 

78  Dies 

79  Drills,  electric 

80  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

83  Enamels,  battery 

84  Enamels,  metal 

85  End  stops 

86  Eyelets 

87  Experimental  work 

88  Fibre  sheet,  vulcanized 

89  Filter  reactors 

90  Fixtures 

91  Fuse  cut  outs 

92  Fuses,  tube 

93  Generators,  high  freque 


94 

r.r 

id  choppers,  r 

otary 

95 

1,1 

id  leak  holder 

96 

C.r 

id.  transmitt 

ng  leaks 

17 

Or 

id  leaks,  tube 

9H 

<;r 

id  leaks,  varia 

ble 

99 

Cr 

inders,  electr 

100 

<;r 

ound  clamp. 

101 

Or 

ound  rods 

10? 

Hr 

ndles,  switch 

10  1 

H« 

ad  bands 

104 

Ik 

ad  phones 

10s 

II. 

106 

He 

neycomb  coil 

adapter. 

10V 

Ho 

10K 

Horns,  composition 

111" 

Hr 

rns.  fibre 

110 

H, 

rns,  mache 

111 

lb 

rns,  metal 

11  ;> 

He 

113 

Hydrometers 

:ators,  polarity 
luctances,  C.  W. 
illation,  molded 
ulation  material 
ulators,  aerial 
ulators,  composition 
ulators,  fibre 
ulators,  high  voltage 
ulators,  cloth 
ulators,  glass 
ulators,  hard  rubber 
ulators,  porcelain 
ns,  soldering 
ks 

ntrol 


its 


114  '.1,1 

115  Indi 

116  Inst 

117  Inst 
US  Ins 

119  In. 

120  In. 

121  In. 

122  Ins 

123  In. 

124  In. 

125  In. 

126  Iro 

127  Jae 

128  Fit 

129  Jars,  battery 

130  Keys,  transmitting 

131  Knobs 

132  Knock-down  panel  u 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arresters 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  units 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instruments 

142  Megohmeters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeters 

148  Minerals 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,      condenser 
leak 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,  honeycomb 

156  Mountings,     inductance 
switch 

157  Name  plates 

158  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeters 

161  Oscillators 

162  Panel  cutting  and  drill.. 

163  Panels,     drilled    and     u 
drilled 

164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  soldering 


you  time  and  money  by  sending  in  the  coupon  below, 
the  coupon. 

168  Patent  attorneys 

169  Phone  connectors,  multi- 
ple 

170  Phonograph  adapters 

171  Plates,  condenser 

172  Plugs,  coil 

173  Plugs,  telephone 

174  Pointers,  dial  and  knob 

175  Poles,  aerial 

176  Potentiometers 

177  Punching  machines 

178  Reinartz  set  parts 

179  Regenerative  set  parts 

180  Receiver  caps 

181  Rectifiers,  battery 

182  Resistance  leaks 

183  Resistance  units 

184  Rheostat  bases 

185  Rheostat  strips 

186  Rheostats,  automatic 

187  Rheostats,  battery 

188  Rheostats,  dial 

189  Rheostats,  filament 

190  Rheostats,     potentiometer 

191  Rheostats,  power 

192  Rheostats,  vernier 

193  Rods,  ground 

194  Rotors 

195  Scrapers,  wire 

196  Screw  drivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving — cabinet 

200  Sets,  receiving — crystal 

201  Sets,     receiving — knock- 


202  Sets,        receiving 
trodyne 

203  Sets,  receiving — 

204  Sets,  re 
quency 

205  Sets,     r 

206  Sets,    re 
tive 

207  Sets,    re 

208  Sets,  re 

209  Sets,  re- 

210  Sets,     r 


Neu- 


ving — reflex 
fing — regenera- 


221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 

226  Stampings 

227  Stators 

228  Stop  points 

229  Switch  arms 

230  Switch  levers 

231  Switch  points 

232  Switch  stops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switches,  ground 

237  Switches,  inductance 

238  Switches,  panel 

239  Switches,  single  and  dou- 
ble throw 

240  Tone  wheels 

241  Towers,  aerial 

242  Transformers,    audio    fre- 
quency 

243  Transformers,  filament 

244  Transformers,  modulation 

245  Transformers,  power 

246  Transformers,  push-pull 

247  Transformers,     radio     fre- 
quency 

248  Transformers,  variable 

249  Transmitters 

250  Tubes, 

251  Tubes, 

252  Tubes, 


253  Tune 

254  Vario 

255  Vario 

256  Va. 

257  Va: 

258  V; 


ative 


ng — Reinartz 
ng — sectional 
ig — short  wave 
ing — super-re- 


211  Sets,  transmitting 

212  Slate 

213  Shellac 

214  Sliders 

215  Socket  adapters 

216  Sockets. 

217  Solder 

218  Soldering  irons,  electric 

219  Soldering  paste 

220  Solder  flux 


259  Variometers,  woodei 

260  Varnish,  insulating 

261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 

265  Win 

266  Wir 
ed 

267  Wir 

268  Wir 

269  Wir 

270  Wir 

271  Wir 

272  Wir 


,  „jrial 

:,  braided  and  strand- 


.,  Litz 
:,  magnet 
;,  platinum 
),  tungsten 


piers,  hard  rubber 
piers,  molded 
piers,  wooden 
meters,  hard  rubber 
eters,  molded 


RADIO  AGE  BUYERS'  SERVICE,  500  N.  Dearborn  St.,  Chicago,  III. 

Please   see  that  I   am   supplied  with   buying  specifications   and    prices  on   the  articles  numbered  herewith: 

1               1               1               1               1               1               1 

_            1               1               1               1               1                1 

1 

I  am  a —  Q  Dealer                  []   Jobber                  ~J    Mfgrs.'  Rep.               □    Manufacturer 

City    _- _ 

-.,    State   . —     . 

*     Tested  and  Approved  b"  RADIO  AGE     * 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


79 


With  the  Manufacturers 


American  Bosch  Enters  Radio  Field 

The  long  expected  entrance  into  the 
radio  field  on  the  part  of  the  American 
Bosch  Magneto  Corporation  will  become 
an  actual  fact  in  January,  when  that  well 
known  automotive  accessory  concern  an- 
nounces to  the  Radio  trade,  the  Bosch 
NoBattry. 

The  new  unit,  as  the  name  implies  is 
a  device  for  the  supply  of  current  to  radio 
sets   without   recourse    to   batteries. 

Although  the  new  unit  is  eventually 
to  be  supplied  in  four  or  five  types  to 
take  care  of  the  various  characteristics 
and  requirements,  the  first  available  type 
will  be  for  the  supplying  of  so-called  B 
current — it  will  secure  its  original  elec- 
trical energy  from  the  house  lighting 
circuit  which,  in  the  majority  of  cities 
and  towns,  is  of  the  alternating  type. 

It  is  the  purpose  of  Bosch  to  also  in- 
troduce a  complete  NoBattry  line,  but, 
among  the  first  to  be  announced,  follow- 
ing the  present  effort,  will  be  a  combina- 
tion unit  for  the  purpose  of  supplying 
both  so-called  A  and  B  energy  and  there- 
by eliminating  from  radio  one  of  the  most 
outstanding  causes  of  annoyance,  trouble 
and  mystifying  reasons  for  loss  of  effi- 
ciency and  unsatisfactory  reception. 

The  Bosch  NoBattry,  which  it  is  ex- 
pected will  be  available  in  January,  is  to 
be  known  as  the  BAN  type,  and  will  sup- 
ply B  current  from  110-115  volt  alternat- 
ing lines,  at  50-60  cycles. 

It  uses  less  current  than  an  ordinary 
25-watt  bulb  and  delivers  a  steady,  even 
flow  of  current,  at  a  constant  voltage,  the 
detector  plate  voltage  being  variable. 


MANUFACTURERS 

SALES 

REPRESENTATIVES 

DISTRIBUTORS 

JOBBERS 

DEALERS 


Not 


i  c  e 


We  are  exclusive  sales  representa- 
tives for  manufacturers  of  cabi- 
nets, tubes  and  storage  bat- 
teries. 

The  RECO  4  tube  tuned  radio 
frequency  set  is  built  for  and 
sold  by  us  exclusively.  This  set 
is  equal  to  any  five  or  ■  six  tube 
set  on  the  market.  Long  distance 
stations  brought  in  with  volume 
and  clarity. 

The"RECO"Low  Loss,  Straight 
Line    variable     condenser     will 
soon  be  ready  for  distribution.  The 
prices  will  be  reasonable. 
Watch   for  our  ad  in   this  paper 
eveiy  month. 

Distributors  or  Sales  Representa- 
tives desired  in  various  territories. 
Please  write  promptly  to 

DAVENPORT  -  HICKORY 
CORPORATION 

329  So.  La  Salle  St.  Chicago,  Illinois 


New  Crystal  Acts  as  Battery- 
Conspicuous  among  new  ideas  being 
introduced  into  radio  is  the  Miller  Bat- 
tery Crystal,  an  invention  of  A.  H.  Miller, 
originator  of  B-Metal  and  president  of 
the  A.  H.  Miller  Radio  Co.,  of  Detroit. 

Much  is  claimed  for  this  new  crystal, 
which  acts  in  the  capacity  of  a  battery 
when  charged  with  what  Mr.  Miller  has 
named  "Pep  Powder." 

Crystals  rectify  radio  signals  in  pro- 
portion to  their  different  resistance  in 
opposite  directions.  The  greater  the  dif- 
ference, the  greater  their  rectifying  prop- 
erties. These  properties  have  been 
amplified  in  the  Battery  Crystals  by 
charging  or  electrifying  the  crystal  and 
keeping  it  electrified  to  a  certain  poten- 
tial. 

In  local  work,  with  a  one  tube  reflex  set, 
about  four  times  the  volume  received  by 
the  use  of  ordinary  crystals  is  obtained 
from  the  Battery  Crystal.  In  fact,  there 
is  enough  volume  to  operate  a  loud 
speaker  with  ease.  On  long  distance 
work,  stations  one  thousand  miles  away 
are  reached  on  one  tube  reflex  sets  using 
Miller  Battery  Crystals.  Furthermore, 
reception  is  as  distinct  and  loud  as  re- 
ceived in  local  work  with  ordinary  cry- 
stals. 

Such  claims  for  crystals  seem  startling 
but  the  Battery  Crystal  seems  to  have 
brought  forth  a  new  era  in  crystal  work. 
This  little  crystal  has  power  enough  to 
deliver  25  to  50  millivolts  right  into  the 
most  sensitive  part  of  the  circuit,  which 
is  in  turn  amplified. 

With  each  Battery  Crystal,  there  is  a 
generous  supply  of  Pep  Powder  included. 
Enough  can  be  purchased  for  50  cents  to 
last  the  user  10,000  hours. 


New  U.  S.  L.  Condenser. 

In  order  to  meet  the  demand  for  a 
finer  product,  David  Wald,  president  of 
the  United  Scientific  Laboratories,  Inc., 
92  East  10th  St.,  New  York  City, 
producers  of  the  famous  U.  S.  L.  line  of 
Radio  apparatus,  has  again  set  to  task 
and  designed  a  line  of  low  loss  con- 
densers, which  spell  the  last  word  in 
mechanical  refinement  and  construction 
for  such  an  article.  The  years  of  exper- 
ience, designing  and  b*uilding  electrical 
motors,  apparatus  and  radio  parts  has 
fitted  Mr.  Wald  to  design  apparatus  with 
the  utmost  precision  and  skill.  The  new 
low  loss  condenser  is  the  result  of  these 
years  of  manufacturing  experience  and 
has  the  unique  and  sound  principles  of 
construction,  as  may  be  found  in  the 
highest  grade  apparatus. 

Rigid  frame  construction  without  de- 
pending upon  insulation  as  part  thereof, 
thereby  eliminating  all  possible  chances 
of  misalignment,  is  one  of  the  features  of 
the  new  condenser.  Straight-line  capa- 
city is  obtained  by  scientific  construction 
cf  rotor  and  stator  plates,  which  are  made 
of  a  special  grade  of  brass.  Pigtail  con- 
nection on  rotor  insures  absolute  elec- 
trical contact  with  rotor. 


DeForest 
License 


\ 


^3,000^10,000  a  year 


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4513  Ravenswood  Ave.,  Oept.  22  Chicago,  III 


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80 


RADIO  AGE  for  February,  1925 


The  Magazine  of  the  Hour 


RADIO  AGE  ANNUAL 

for  1925 

Now  Ready! 

With  a  Thirty-Two  Page  Blueprint  Section 
of  Record- Breaking  Hookups! 


AT  LAST!  THE  RADIO  AGE  ANNUAL  for  1925 
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THE  ANNUAL  for  1925  is  the  result  of  three  years 
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the  cream  of  the  radio  hookups  that  have  made  their 
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thusiasts. 

One  hundred  and  twenty  pages  of  new  hookups, 
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THE  predominating  feature  of  the  RADIO  AGE 
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as  actual  working  drawings.  Every  one  of  the  hookups 
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Complete  instructions  for  building  every  kind  of 
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How  to  read  and  understand  hookups. 
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Building  your  first  simple  set. 
How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set. 
How  to  amplify  any  kind  of  set. 
Making  a  reflex  set. 
Building  your  first  Reinartz  set. 
The  renowned  Baby  Heterodyne  No.  1. 
Adding  audio  and  radio  stages  to  the  Baby  Het. 
How  to  make  a  battery  charger. 
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How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super-heterodyne  for  the  super  experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

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2-25  FIRST  CALL  FOR  THE  ANNUAL  FOR  1925!     NOW  READYl 


The  Real  Secret  of  Clear 

Tone  and  Quiet  Operation 

told  in  simple,  every -day  terms  which  everyone  can  understand 


SOMETHING  has  recently  happened  to  radio 
•  which  makes  it  a  much  simpler,  more  depend- 
able and  sweeter  toned  instrument.  That  something 
is  the  complete  elimination  of  internal  noises  by  the 
radio  inventor,  Carl  Pfanstiehl. 

The  technical  means  which  he  employed  is  a 
scientifu  5tory  of  great  interest  to  radio  engineers. 
The  average  radio  user  does  not  care  about  that.  But, 
briefly,  in  popular  language,  this  is  what  he  did: 

For  years  he  had  observed  what  complicated  de- 
vices were  being  used  to  neutralize  stray  oscillations 
in  the  set,  the  oscillations  of  radio  energy  which 
cause  chatter  and  squeaks  and  squeals,  and  often  dis- 
tort speech  or  music.  Potentiometers  were  employed 
and  extra  condensers.  These  are  a  makeshift.  They 
only  partially  succeed;  and  they  need  adjustment. 

He  made  up  his  mind  that  some  way  could  be 
found  to  go  to  the  root  of  the  trouble  and  elimi- 
nate it  entirely,  instead  of  merely  trying  to  offset  it. 


By  tracing  back  the  oscillations  to  their  separate 
sources  he  discovered  their  true  nature  and  how  to 
keep  them  out.  Nobody  had  ever  known  this  before. 

The  remedy  is  as  simple  as  it  is  effective.  All 
complicated  devices  are  dispensed  with.  He  so  de- 
signed the  structural  relationship  between  coils 
and  condensers  that  the  stream  of  radio  energy  is 
perfectly  controlled;  there  is  no  feedback  causing 
stray  oscillations.  All  the  radio  energy  is  utilized 
in  developing  the  true  signal.  The  set  is  internally 
noiseless.  Speech  and  music  come  in  without  in- 
terference. You  get  a  liquid  clear  enunciation  of 
every  syllable  and  a  supremely  pure  tone. 

See  and  hear  this  new  system  that  is  revolutionizing 
radio — the  Pfanstiehl  Model  7 — at  your  dealer's.  Or  let  us 
send  you  free  descriptive  booklet. 

Dealers :  Write  for  the  special  Pfanstiehl  proposition. 

PFANSTIEHL  RADIO  COMPANY 

Highland  Park  2  2  Second  Street  Illinois 


MODEL  7  RECEIVER 
A  5-tube  Receiver  using  the  new  system  of  tuned  radio  frequency 

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Jf/iWeS  WORKOF  6 


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Trirdyn  Special,  $60.00 

tubes  ind  Crosier  Pbooet  $75.75 


Jit  the  _, 


Crosley  One  Tube 

Model  50,  $14.50 

WHli  tob«  lid  Crosier  Fhooo  IO.ZS 


SINCE  the  inception  of  radio,  the  results  obtained  with 
Armstrong  Regenerative  Receivers  have  been  the  goal  of 
comparison  for  all  others.  Trick  circuits  have  been  de- 
signed to  get  around  the  Armstrong  Patent  hoping  to  obtain 
results  "just  as  good."  This  has  resulted  in  the  use  of  more 
tubes,  necessary  without,  but  unnecessary  with  regeneration. 
This  is  one  reason  why  Crosley  Radios,  licensed  under  Arm- 
strong U.  S.  Patent  No.  1,113,149  have  performed  everywhere 
so  remarkably  on  so  few  tubes. 

The  Crosley  Trirdyn,  employing  Armstrong  Regeneration 
combined  with  tuned  non-oscillating  radio  frequency  ampli- 
fication and  reflexed  audiofrequency  amplification  and  using 
only  three  tubes,  consistently  gives  greater  selectivity,  more 
volume  and  wider  range  than  can  be  obtained  where  five  or  six 
tubes  are  employed  without  regeneration.  With  no  regenera- 
tion, two  stages  of  radio  frequency  amplification,  requiring  at 
least  two  additional  tubes,  must  be  employed  in  front  of  the 
detector  tube  to  get  the  same  results  as  furnished  by  one  tube 
where  regeneration  is  used. 

Every  additional  tube  means  additional  expense;  an  added  dial 
to  tune,  greater  difficulty  in  operation,  more  distortion  and 
more  tube  noises.  The  three  tube  Crosley  Trirdyn  has  only 
two  dials.  These  operate  but  two  circuits,  making  tuning 
and  logging  very  easy. 

You  can't  beat  the  results  obtained  from  an  Armstrong  Re- 
generative Crosley  Radio.     A  trial  will  convince  you. 

BEFORE  YOU  BUY— COMPARE 
YOUR  CHOICE  WILL  BE  A  CROSLEY 

For  Sale  By  Good  Dealers  Everywhere 

CrOlley  Regeneratite  Receivers  are  Licensed  under  Armstrong  U.  S.  Patent  1  113,149 
Prices  West  of  the  Rockies  add  10% 

Write  for  Complete  Catalog 

THE  CROSLEY  RADIO  CORPORATION 

Powcl  Crosley.  Jr.,  President 

263  Sassafras  St.  Cincinnati,  Ohio 

Crotlty  Owns  and  Optratts  Broadcasting  Station  WLW 


Better -Costs  Less 

Radio 


Crosley 

Head  Phones 

Better — Cost  Less 

$3.75 


Crosley  Two  Tube 
Model  51.  $18.50 

tfki  talu  ud  Croile;  Phoou  J3<t25 


Croaley  Tbree  Tube 

Model  52,  $30.00 

ffitk  taWi  id!  Croilsy  Pbow.  J45.7S 


Croiley  Trirdyn  Newport,  $85, 

Wilk  tale!  »d  Qo.lc J  PhoK.    $100.75 


*     Tested  and  Approved  by  RADIO  AGE     * 


me  of  the  Hour 

^  Th&Driginal 

"MysterfMan ' '  of  Radii 

Blueprint  Section  Ever} 

J'  Month 


ARCH  192 


CENTS 


EET  YOUR  BROADCAST  FAVORITES 


0 


mil  Si® 


They  Cost  More 


But  They  Do  More 


Super-Zenith  VIII— 
the  ideal  radio  set 
for  the  fine  home 


To  choose  at  will  * 

one  glorious  voice- 
one  majestic  symphony 

A  few  blocks  from  your  home  a  powerful  station  may 
be  on  the  air.  Other  locals — six,  eight  or  ten  of  them — 
may  be  broadcasting  at  the  same  time. 

Imagine,  now,  the  satisfaction  of  tuning  them  all  out  and 
bringing  in  distant  cities.  The  air  a  chaos  of  sounds, 
yet  out  of  that  chaos,  from  across  the  continent,  one 
glorious  voice,  one  majestic  symphony — the  very  pro- 
gram that  you  wanted  most  to  hear — and  as  clear  and 
appealing  as  though  it  were  in  the  next  room. 

The  ability  to  take  your  choice — that  is  what  you 
want  above  all  else  in  radio  reception.  And  it  is  that 
very  property,  built  into  the  Zenith,  which  makes  it 
supreme  among  fine  radio  sets.  The  joy  of  possessing 
such  an  instrument  is  all  the  greater  from  the  fact  that 
its  beauty  of  design  and  excellence  of  construction  speak 
quietly  of  its  distinction. 

Before  you  choose  the  receiving  set  to  occupy  the  place 
of  honor  in  your  home,  be  sure  to  see  and  try  the 
Zenith.  Its  beauty  you  will  recognize  at  a  glance.  Its 
extraordinary  capabilities  any  Zenith  dealer  will  be  glad 
to  demonstrate. 

Dealers  and  Jobbers: 
Write  or  wire  for  our  exclusive  territorial  franchise. 

ZENITH  RADIO  CORPORATION 

332  South  Michigan  Avenue,  Chicago 
ZENITH — the  exclusive  choice  of  MacMillan  for  his  North  Pole  Expedition 


The  complete  Zenith  line  ranges  in 
price  from  $95  to  $550. 
With  either  Zenith  3R  or  Zenith  4R,  sat- 
isfactory reception  over  distances  of 
2,000  to  3,000_  miles  is  readily  accom- 
plished, using  any  ordinary  loud 
speaker.  Models  3R  and  4R  licensed  un- 
der Armstrong  U.  S.  Pat.  No.  1,113,149. 
They  are  NON-RADIATING. 

Zenith  4R  -    -     $95 
Zenith  3R  -    -$160 

The  new  Super-Zenith  is  a  six-tube  set 
with  a  new,  unique,  and  really  different 
patented  circuit,  controlled  exclusively 
by  the  Zenith  Radio  Corporation.  It  is 
NOT  regenerative. 

SUPER-ZENITH  VII  —  Six  tubes-2 
stages  tuned  frequency  amplification  — 
detector  and  3  stages  audio  frequency 
amplification.  Installed  in  a  beautifully 
finished  cabinet  of  solid  mahogany  — 
44%  inches  long,  16%  inches  wide,  10% 
inches  high.  Compartments  at  either 
end  for  dry  batteries.  Price  (ex-  fesy  *2.f\ 
elusive  of  tubes  and  batteries)  <p£  J\J 
SUPER-ZENITH  VIII—  Same  as  VII  ex- 
cept— console  type.  Price  (ex-  fh^j  c.r\ 
elusive  of  tubes  and  batteries)  *p£5\J 
SUPER-ZENITH  IX  —  Console  model 
with  additional  compartments  contain- 
ing built-in  Zenith  loud  speaker  and  gen- 
erous storage  battery  space.  Price  (ex- 
clusive of  tubes  and  bat-  ao  cr\ 

teries) Jpj  JV 

SUPER-ZENITH  X— Contains  two  new 
features  superseding  all  receivers.  1st— 
Built-in,  patented,  Super-Zenith  Duo- 
Loud  Speakers  (harmonically  synchro- 
nized twin  speakers  and  horns), designed 
to  reproduce  both  high  and  low  pitch 
tones  otherwise  impossihie  with  single- 
unit  speakers.  2nd- Zenith  Battery 
Eliminator,  distinctly  a  Zenith  achieve- 
ment. Requires  no  A  or  B  bat-  <h££/> 
teries.  Price  (exclusive  oftubes)  Ipj  D\) 
Price  (without  battery  eliminator)  $450 
All  Prices  P.  O.  B.  Factory. 


ZENITH  RADIO  CORPORATION,  Dept.     C-3 
332  South  Michigan  Avenue,  Chicago,  111. 

Gentlemen:  Please  send  me  illustrated  literature  giving 
full  details  of  the  Super-Zenith. 

Name 


#     Tested  and  Approved  by  RADIO  AGE     # 


RADIO  AGE  for  March,  1925 


The  Magazine  jf  the  Hour 


Earns  College 
Education 

1  entered  the  mari- 
time service  of  the  Radio 
Corporation  of  America 
and  served  several 
months  on  board  ship. 
I  not  only  had  the  ad- 
vantages of  visiting  for- 
eign countries  at  no  cost 
to  me  but  I  was  also 
able  to  save  enough 
money  to  pay  for  my 
tuition  to  college. 

G.  E.  Rogers, 
Troy,  N.  Y. 


§405  in  One  Month 
I  cleaned  up  S405  in 
one  month  recently.  Not 
so  bad — is  it — -for  a 
fellow  who  just  com- 
pleted your  course  a 
short  time  ago? 

Emmet  Welch, 
Peculiar,  Mo, 


Train  at  Home  For  Big  Money 

m  RADIO  / 

Thousands  earning  $50  to  $200  a 

week  in  easy,  interesting  work. 

You  can  do  it! 

Radio  just  teems  with  money  making  opportunities.  Every 
Radio  set  which  is  sold  means  profit  in  somebody's  p  ket.  Every 
broadcasting  station  erected  means  big  pay  for  Raaio  Engineers, 
Radio  Mechanics,  Operators,  etc.  Thousands  are  "cleaning  up," 
fortunes  are  being  made  almost  overnight  in  this  fascinating  busi- 
ness. Big  salaries,  interesting,  easy  work,  short  hours,  and  a  won- 
derful future  are  offered  to  ambitious  men  who  get  into  Radio  now! 

One  of  our  recent  graduates  is  making  over  $400  a  month  in  his 
own  business.  Another  has  increased  his  pay  $1,300  a  year.  Still 
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Tamaqua  Pa. 


Pay    Increases    Over 
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where from  $75  to  $150 
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Greensburg,  Pa. 


NATIONAL  RADIO  INSTITUTE,  Dept.  53EB, 
Washington,  D.  C. 

Without  obligation  send  me  your  book,  "Rich  Rewards 
in  Radio,"  which  tells  all  about  the  opportunities  in 
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National  Radio  Institute 

Dept.  53EB  Washington,  D.  C. 


Name— 

Street — Occupation- 
City State 


RADIO  i  March,   1925 


The  Magazine  of  the  Hour 


agazine  of  the  Hour 

stablished  March,  1922 

with  abncH   s  combined  radio  topics 


Volume  4  March,  1925  Number  3 

ONTENTS 

--,  s 

Radio  F        rials..  - 4     ' 

How  Super-P  ~"T^-king  Out 9 

A   "Permanf  ....13 

Don't  Blair  -.16 

A  5-Tube  Radio  Frequ^.  —17 

By  H.  Frank  riot 

Saving  Current  with  a  Double  Grid  'Iul.^..        19 

By  C.  R.  Bluzat 

How  to  Wind  Low  Loss  Coils. 20 

What  the  Eclipse  Meant  to  Radio— 21 

The  New  Baby  C  -and  Super-Het — 23 

By  Paul  Green 

A  Short  Wave  Receiver 25 

By  C.  Harold  Dillon 

What  Radio  is  Leading  to... 27 

By  Edmund  H.  Eitel 

The  Sleuths  of  Honeymoon  Camp 29 

A  Story — By  Frank  Honeywell 

"What    the    Broadcasters    are    Doing" — RADIO 
AGE  Studio-Land  Feature  Section 31 

RADIO  AGE  BLUEPRINT  SECTION 
I.  A  Two-Tube  Ultra  Audion._ 39 

II.  A  Regenerative  Reflex  Circuit 43 

By  John  B.  Rathbun 

Pickups  and  Hookups  by  Our  Readers 49 


Radio  Age  is  published  monthly  by  RADIO  AGE,  Inc. 
Member:      Audit  Bureau  of  Circulations. 


Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500   N.  Dearborn   Street,    Chicago,    111. 
Publication   Office,    Mount    Morris,   111. 

Frederick  A.  Smith,  Editor 
Russell  H.  Hopkins,  Associate  Editor 
Frank  D.  Pearne,  Technical  Editor 
C.  H.  Dillon,  Technical  Assistant 
M.  B.  Smith,  Business  Manager 

Advertising  Director 
HARRY  A.  ACKERBURG 


Eastern  Representative 
DAVIDSON   &   HEVEY,    17  West  42nd  St.,  New  York  City 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 

preceding  date  of  issue 

Issued  monthly.  Vol.  4,  No.  3  Subscription  price  $2.50  a  year. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris,  Illinois,  under  the 

Act  of  March  3,  1879. 


Copurioht,  1SSS,  by  RADIO  AGE,  Ine. 


A  Chat  With 
the  Editor 

THE  month  of  March,  1925,  will 
develop  a  situation  of  vital 
radio  importance.  It  will  not 
involve  any  new  or  radical  change  in 
the  construction  of  receiving  sets.  It 
will  not  have  any  relation  to  radio 
engineering  triumphs.  It  will  go 
vastly  farther  than  either  of  those 
possibilities.  Unless  Radio  Corpora- 
tion asks  and  gets  more  delay,  the 
month  of  March  will  do  much  to 
settle  the  question  as  to  whether 
there  is  a  radio  trust. 

The  Federal  Trade  Commission 
doesn't  seem  to  care  a  hoot  about 
who's  who.  The  Commission  exhibits, 
however,  a  lively  interest  in  what's 
what.  The  Commission  will  hear 
what  eight  big  corporations  have  to 
say  in  reply  to  the  charge  that  they 
have  entered  into  a  conspiracy  to 
restrain  trade— meaning  the  radio 
trade.  The  eight  big  corporations 
say  it's  all  bosh.  Radio  Corporation 
not  only  says  "bosh,"  but  it  is  highly 
indignant  that  the  United  States 
Government  should  presume  to  ask 
questions  of  a  corporation  that  ad- 
mits it  was  organized  with  purely 
patriotic  motives. 

But  what  we  started  to  say  was 
that  RADIO  AGE  will  be  represented 
at  that  Federal  Trade  Commission 
hearing  in  Washington.  RADIO 
AGE  is  going  to  tell  the  whole  truth 
about  the  testimony.  It  may  be  that 
our  thousands  of  technically  Minded 
readers  will  not  care  to  have  a  few  of 
their  diagrams  and  formulas  displaced 
by  the  story  of  a  trust  battle  in  Wash- 
ington. 

But  we  insist  that  our  editorial 
judgment  will  be  vindicated  in  the 
long  run.  The  scotching  of  an  illegal 
radio  combine  is  a  job  worth  while. 
It  eventually  would  mean  much  to  the 
buyer  of  tubes  and  the  seeker  of 
patents  and  to  the  manufacturer  who 
is  weary  of  leaping  into  shell  holes 
when  the  heavy  trust  artillery  begins 
to  lob  'em  over. 

What  we  want  especially  to  see  is 
a  picture  of  Sarnoff  and  Boucheron, 
the  R.  C.  A.  twins,  in  action  at  Wash- 
ington. With  the  whole  country 
watching,  it  ought  to  be  good.  Read 
our  reports  on  this  proceeding. 

Editor  of  RADIO  AGE. 


RADIO  AGE  for  March,  1925 


The  Mag  zine  of  the  Hour 


There's  more  life 
Eveready  Batteries 

Buy  Eveready  "B"  Batteries  and  you  get  elec- 
tricity in  its  surest,  safest  and  most  compact  form. 
They  reduce  your  operating  expense.  New  de- 
velopments in  the  Union  Carbide  and  Carb  n  Re- 
search Laboratories,  Inc.,  have  been  converted 
into  new  manufacturing  processes  in  the  Ever- 
eady factories.  Good  as  they  always  have  been, 
Eveready  "B"  Batteries  are  much  better  today. 

The  Eveready  achievement  of  giving  \  ou  more 
hours  of  "B"  Battery  service  for  less  money  has 
cut  the  cost  of  running  receivers  '"  half,  and  in 
some  cases  the  new  Evere?  i{  s  make  "B"  Battery 
expense  only  a  third  of  ;  hat  it  used  to  be. 

There  is  an  Eveready  Radio  Battery  for  every 
radio  use. 

Manufactured  and  guaranteed  by 

NATIONAL    CARBON    COMPANY,    Inc. 

Headquarters  for   Radio  Battery  Information 

New  York  San  Francisco 

Canadian  National   Carbon    Co.,   Limited,  Toronto,  Ontario 

EVEREADY 

Radio  Batteries 

.,         —they  last  longer 


*     Tested  and  Approved  by  RADIO  AGE     ¥ 


4  RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


THE  railroad;  skve  teken  a  kick  at  radio.  They 
have  increas  .  freigl  .  rates  on  radio  merchandise 
fifty  per  ce  (ri  the  Eastern  and  Western  terri- 
tory and  one  hi  ;  r:  per  cent  in  the  South.  There 
does  not  seem  tc  be  the  slightest  justification  for  such 
an  arbitrary  action.  It  appears  that  the  railroads 
believe  the  new  radio  industry  is  not  yet  sufficiently 
organized  to  make  \  good  defense.  Cold  blooded, 
isn't  it? 

The  Radio  Ma  rs'  Association  has  filed  a 

protest  against  ie   i  I    for  its  sus- 

pension  until    t  ite   ;'  ferce  Commission 

shall  have  had  a  ilea,  ing  un  tne  manutacturers  objec- 
tions. It  is  expected,  nie  express  companies  will 
follow  the  example  of  the  railroads. 

A  special  transportation  committee  of  the  RMA  is 
composed  of:  J.  M.  Stone,  Operadio  Corporation, 
Chairman;  E.  N.  Rauland,  Ail-American  Radio  Cor- 
poration; Frank  Reichmann,  The  Reichmann  Com- 
pany; Arthur  Freed,  Freed-Eisemann  Radio  Cor- 
poration; Powel  Crosley,  Jr.,  Crosley  Radio  Corpora- 
tion; A.  U.  Howard,  Dubilier  Condenser  &  Radio 
Corporation;  George  A.  Scoville,  Stromberg-Carlson 
Tel.  Mfg.  Company;  Walter  L.  Eckhardt,  Music 
Master  Corporation.  This.committee  is  being  strongly 
backed  by  special  committees  in  different  parts  of  the 
United  States,  the  chief  object  being  the  raising  of 
funds  to  defend  the  radio  industry  against  the  railroads. 

Every  manufacturer,  jobber,  wholesaler  and  retailer 
in  the  United  States  is  asked  to  contribute  to  the  fund 
now  being  raised.  Checks  can  be  sent  either  directly 
to  the  Radio  Manufacturers'  Association  office  or  to 
Mr.  Arthur  Freed,  treasurer  of  the  special  committee, 
care  Freed-Eisemann  Radio  Corporation,  Brooklyn, 
N.  Y.  The  address  of  the  Radio  Manufacturers' 
Association  is  123  W.  Madison  St.,  Chicago. 

The  reason  we  call  attention  to  this  situation  is  that 
if  costs  are  added  to  the  manufacture  and  distribution 
of  radio  merchandise,  the  manufacturers  will  be  forced 
to  charge  the  public  more  for  their  goods.  That  means 
the  radio  fan  will  pay  the  bill,  or  part  of  it.  Therefore 
it  is  to  the  interest  of  every  fan  to  support  the  opposi- 
tion to  the  railroad  and  express  companies. 

ANOTHER  device  for  increasing  the  cost  of  radio 
is  the  proposal  in  some  quarters  that  a  tax  be 
voluntarily  assumed  by  radio  manufacturers,  the 
revenue  from  which  may  be  devoted  to  the  payment 
of  radio  entertainers.  This  would  result  in  an  indirect 
tax  on  the  radio  fans.  It  would  work  out  just  as  the 
added  freight  tax  would.  The  question  as  to  who  shall 
pay  radio  estertainers  has  been  discussed  at  length 
and   it   seems   far   from   settlement.      One   important 


broadcaster  tells  us  he  doesnt  think  it  necessary  to 
pay  entertainers  because  most  of  them  are  able  to 
get  more  than  full  value  from  the  publicity  they  get 
from  studio  announcers  and  press  notices.  Many 
professional  musicians  and  singers  demand  pay  and 
many  are  pleased  to  sing  or  play  without  direct 
remuneration.  The  American  Society  of  Composers 
Authors  and  Publishers  has  carried  on  a  hard  battle 
against  the  free  use  of  copyrighted  music  in  broad- 
casting. The  Actors'  Equity  Society  is  now  demand- 
ing that  its  members  obtain  pay  for  their  contri- 
butions to  the  nation's  entertainment.  Some  stations 
in  the  East  are  paying  their  entertainers.  It  is  a 
problem  that  the  broadcasters  themselves  will  have  to 
settle.  It  may  be  found  advisable  to  put  a  tax  on 
manufacturing  and  thus  indirectly  tax  the  buyers  of 
sets.  But  some  aspects  of  the  demands  of  entertainers 
appear  to  be  somewhat  extortionate.  There  is  no  hurry 
about  a  settlement,  as  the  present  entertainment  is 
pretty  fair. 

WHEN  will  the  sale  of  radio  sets  reach  the  satura- 
tion point?  A  long,  long  time  from  now.  There 
are  said  to  be  14,000,000  talking  machines  in  use.  It 
is  not  improbable  that  the  ultimate  number  of  receiving 
sets  will  equal  that  number.  In  view  of  the  fact  that 
the  radio  receiver  is  a  more  fascinating  musical  instru- 
ment it  is  likely  that  the  figure,  14,000,000,  is  con- 
siderably too  low.  There  are  17,000,000  automobiles 
in  use.  It  does  not  seem  improbable  that  as  many 
radio  receivers  eventually  will  be  installed.  Some 
observers  predict  that  20,000,000  will  be  the  ultimate 
figure.  Anyhow  it  is  quite  apparent  that  we  are  far 
short  of  the  saturation  point.  This  is  more  interesting 
to  the  manufacturer  than  it  is  to  the  buyers  of  sets. 
But  it  is  vastly  important  to  the  public.  It  means 
this  cultural,  educational  humanizing  radio  influence  is 
to  be  extended  beyond  its  present  boundaries. 

THE  CHICAGO  Civic  Opera  Association  has  closed 
its  season  in  Chicago  with  a  deficit  of  $25,000  more 
than  last  year.  The  managers  of  the  opera  are  wonder- 
ing why  the  music-loving  public  has  failed  to  respond 
to  grand  opera  as  in  former  years.  Many  reasons  have 
been  set  forth,  such  as  the  choice  of  lesser-known  operas, 
the  singing  of  the  operas  in  foreign  tongues,  etc.  But 
if  we  were  asked  to  state  our  opinion  frankly,  we'd 
venture  the  statement  that  grand  opera  in  Chicago 
wasn't  a  success  last  season  because  it  wasn't  broadcast 
over  the  radio.  After  the  1923  season  the  Association 
discontinued  its  policy  of  broadcasting  three  per- 
formances a  week  because  it  felt  radio  was  "keeping 
people  home  instead  of  sending  them  to  the  opera.  This 
year's  experience  proves  their  excuse  hardly  holds  water. 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour  5 


What 

Reliable  Radio 
Means  to  Yon 


^tf/AMEBICAH 

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((  An  assurance  that,  when  you  try  out  a  hook-up,  you  can 
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RADIO  AG     to.    vlai:i,  1925 


The  Magazine  of  the  Hour 


TAKE  THE  GUESS 
W(      K  OUT  OF 
ADIO 

USE       -T  PARTS 


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GET  YOUR  COPY  OF 
BETTER  TUNING 

A  40-page  book,  containing  hook- 
ups (B-T  No.  1  and  No.  2  are  in- 
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sands of  set  builders  and  operators. 
See  your  dealer' or  send  10c  for  a 
postpaid  copy. 


X 


B  Vs  reputation  for  never  having 
put  out  a  part  that  was  not  a  con- 
tinued success  means  a  great  deal  to 
you.  It  means  that  you  can  build  any 
tried  and  proved  circuit,  using  the 
proper  B-T  parts,  and  be  assured  of 
good  results .  Buy  proved  parts — not 
experiments.     Use  B-T  apparatus. 

READ  WHAT  OTHER 
PEOPLE  HAVE  DONE 

Tito  Schipa,  the  world's  greatest  tenor, 
praises  the  "Nameless"  set  installed  in 
his  apartment  at  the  Congress  Hotel, 
Chicago,  a  few  blocks  from  several  power- 
ful broadcasting  stations.  Part  of  his 
statement  follows: 

"After  using  several  other  well-known 
radio  receiving  sets  and  discarding  same, 
to  say  that  I  am  well  pleased  with  your 
set  is  speaking  very  mildly.  The  volume, 
selectivity,  quality  of  tone  and  ease  with 
which  distant  stations  are  tuned  in 
whilst  other  Chicago  stations  were  radio- 
casting, was  simply  marvelous  and  al- 
most beyond  understanding.  I  suppose 
that  you  will  hardly  believe  me  when  I 
tell  you  I  tuned  in  42  stations  my  first 
night,  Monday,  December  8,  1924,  in- 
cluding one  Pacific  coast  station,  KHJ." 

Roanoke,  Va.,  Dec.  26,  1924. 
I  have  completed  your  No.  1,  using  your 
tuner  and  condenser.     It  is  the  clearest 
and  most  powerful  regenerative  set  that 
I  have  ever  heard.  C.  F.  K. 

Denver,  Pa.,  Dec.  23,  1924. 
Have  just  received  my  certificate  showing 
that  I  have  received  European  stations. 
I  used  your  tuner  and  condenser. 

E.  F.  B. 

Kirkwood,  Ga.,  Dec.  24,  1924. 
I  enclose  a  list  of  54  stations  received  on 
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RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


a 


m 


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| 

i 

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l>/4 

611  WHR 

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69  WHR 

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3 

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% 

69  WHR 

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22 

1. 

3 

1  UV-200 

2  UV-201A 

l'/2 

611  RHR 

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69  WHR 

14 

HUH 

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UV-201A  L 

I 

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w* 

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IPS 

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4| 

For  & 
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SIBI 


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JSq  Magazine  (fthe  Hour 


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A  Monthly  Publication 

Devoted  to  Practical 

Radio 


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Editor 


felHE 


An  Up-to-Date  Radio  Survey — 

HowSUPER-POWERw  Working 


AMERICAN  broadcasters  have  not 
undertaken  what  is  technically 
known  as  "super-power"  broad- 
casting yet,  but  nine  Class  B  stations 
have  been  authorized  by  the  Department 
of  Commerce  to  increase  their  power  over 
1,000  watts,  and  so  far  results  are  satis- 
factory. Before  many  months  there  will 
be  about  thirty  of  these  high-powered 
broadcasting  stations  on  the  air,  carry- 
ing their  programs  to  ever  hamlet  and 
farm  where  fairly  good  radio  sets  are  in  use. 

Although  some  of  these  stations  have 
been  operating  for  three  months,  com- 
plaints received  by  the  radio  bureau  of 
the  Department  of  Commerce  are  few 
and  are  considered  as  inconsequential. 

"The  development  of  increased  power 
in  broadcasting  to  date  has  been  suc- 
cessful, and  the  Department  stands  ready 
to  grant  further  licenses  to  applicant  B 
stations  which  are  qualified,"  W.  E. 
Downey,  recently  appointed  Technical 
Radio  Expert,  declared  to  the  writer. 

"Two  more  stations  have  been  authoriz- 
ed to  make  a  second  step  in  power,"  he 
continued.  "WEAF  of  New  York,  and 
KGO,  at  Oakland,  Calif.,  were  success- 
fully operated  on  1500  watts  without 
causing  undue  interference,  and  recently 
were  increased  to  2000  watts  without 
complaint  from  local  or  distant  fans," 
he  pointed  out,  explaining  the  Depart- 
ment's regulations  for  the  use  of  in- 
creased power.  Authority  is  granted 
only  in  an  experimental  way  to  class  B 
stations,  to  increase  their  power  to  1500 
watts,  which  may  be  increased  from  time 
to  time  in  steps  of  500  watts  up  to  5000 
watts  or  5KW,  which  is  also  the  limit  in 
power  of  most  broadcasting  transmitters. 
But  regulations  provide — and  this  is 
the  main  point,  that  the  field  supervisors 
of  radio  are  satisfied  that  no  undue  inter- 
ference has  been  caused  with  other 
stations  or  with  receiving  set  results. 
Applicants  agree  to  reduce  their  power  if 
the  Department  or  its  representatives 
deem  it  necessary  in  the  interest  of  the 
public,  but  not  one  has  been  ordered  to 
do   so. 

Must  Be  a  Limit 

TODAY    the    Department    feeis   confi- 
dent that  the  experiment  is  a  success 
But  at  the  same  time  realizes  that  there  is 


By  CARL  H.  BUT  MAN 

Very  Few  Complaints 
Received  by  Officials 


a  limit.  If  all  the  B  stations  increased 
their  power,  complications  might  arise — 
there  would  be  little  doubt  of  this  if  all 
seventy-nine  stations  of  this  class  went  to 
5KW  and  stayed  there.  Such  a  situa- 
tion is  not  anticipated  for  some  time 
at  least,  however. 

Such  reports  as  have  come  in  indicate 
that  increased  power  is  causing  some 
interference,  although  it  is  not  considered 
as  serious.  Right  here  Mr.  Downey 
pointed  out  that  the  Department  is  soon 
advised  when  a  serious  condition  arises. 
It  is  flooded  with  telegrams  and  letters, 
just  as  was  the  case  when  the  fight 
against  increased  power  was  staged  at 
the  time  of  the  last  radio  conference. 
Thousands  of  fans,  many  of  whom  have 
since  changed  their  minds,  protested 
against  so  called  "super  power,"  fearing 


[Harris  &  Ewing  Photo] 

W.  E.  Downey,  recently  appointedradio  tech- 
nical expert  of  the  Department  of  Commerce 


that  a  monopoly  of  the  air  was  planned 
and  that  local  stations  would  be  blanket- 
ed. Some  even  went  so  far  as  to  worry 
about  the  safety  of  their  own  receiving 
sets,  which  they  feared  might  be  damaged 
by  this  "super"  bugaboo.  Nothing  to 
compare  with  this  flare-up  has  occurred 
since  the  first  high-power  experimental 
license  was  granted  to  WTAM  at 
Cleveland  in   November. 

An  observer  on  the  Pacific  coast  reports 
that  he  doesn't  notice  any  more  inter- 
ference there  now  than  there  was  on  500 
watts,  and  he  has  two  stations — KGO, 
Oakland,  and  KFI,  Los  Angeles,  to  test 
on.  Two  Florida  fans  complain  of 
difficulty  in  separating  KFI  from  stations 
WCAP  and  WRC  at  Washington,  all 
of  which  are  on  the  same  wavelength. 
This  situation  is  also  reported  locally 
in  Washington.  From  New  Mexico  two 
other  listeners  complain  that  since  the 
increase  in  power,  a  Los  Angeles  and  a 
Dallas  station  interfere,  although  they 
are  ten  kilocycles  apart.  These  letters 
are  typical,  although  one  other  kick  is 
interesting.  Some  fans  in  Cleveland  and 
its  environs  complained  of  increase 
in  power  by  WTAM  before  the  increase 
was  authorized  and  before  this  station 
boosted  its  wattage.  This  type  of  com- 
plaint is  classified  along  with  the  "buga- 
boo chasers,"  which  do  not  worry  radio 
officials. 

Generally,  Mr.  Downey  says  that  some 
difficulty  is  reported  in  the  form  of  a 
clashing  of  side  bands,  although  there  is 
no  heterodyne  whistle.  This  effect  pro- 
duces something  like  the  result  when  two 
people  try  to  talk  over  a  party  telephone 
line  at  the  same  time,  or  similar  to 
"cross-talk"  of  some  telephone  systems. 
It  can  be  overcome  when  good  sets  are 
well  operated,  he  feels  certain. 
10  Kilocycles  Apart 
TJTERE  the  official  paused,  and  gave 
■*-■*■  the  writer  an  earful!  "All  these  B 
stations  which  have  been  granted  in- 
creased power  are  on  wave  bands  sepa- 
rated by  at  least  ten  kilocycles,"  he  said, 
"and  most  of  them  are  500  miles  apart. 
If  we  authorize  increased  power  to  two 
stations  in  the  same  city,  they  should 
operate  on  remote  channels,  at  least 
100  kilocycles  apart.     With  this  system 


10 


RADIO  AGE  uch'  1925 


The  Magazine  of  the  Hour 


n    the   fans     rumors   have   it    that    the    contemplated  fort  to  reduce  interference  and  to  create 

i  the  selecti-     super-broadcaster    of     a    large    corpora-  more    channels    for    the    growing    broad- 

tion  in  the  neighborhood  of  New  York,  is  casting  service.     At  that  time  there  were 

to  become  a  reality  before  many  months.  519  broadcasting  stations  of  three  classes. 

Outside    the    United    States    the    urge  They    included    fifty-seven    class    B,    or 

for  more  power  is  also  felt.  higher- powered     stations;     seventy-eight 

The  operation  of  a  set  with  between  5  class   A,    and   382   class    C   stations,   the 

and  10  KW  power  in  Canada  is  said  to  last   stations   on    the   original   broadcast 

be  successful.     A  new  British  broadcaster  wave  of  360  meters.     Many  more  stations 

rated  at  25  KW,  but  capable  of  100  KW,  were    contemplating    transferring    to    a 

is  being  erected  at  Daventry  to  operate  class    B    status,    but    wavelengths    were 

fere"at~all   when'usi                          ;>    may     on  1600  meters-     lt  is  heralded  with  any_  getting  very  scarce  in  that  group,  where 

nterf ere  and  they  dc                     instances     thing  but  fear  of  interference,  even  in  that  each    station    desired    and    expected    an 


in  operation,  the  reaction  i 
will  be  in  exact  proportion  tea 
vity  of  their  sets.  Tt  ,se  »c  complain 
will  probably  be  op.  ',,,  Poorly  de- 
signed sets  which  an-  '*  ;ve>  or 
they  will  be  listener's  r.  *™.°  -an  /une 
their  sets.  It  is  usual!  '  '?'=  ^P*  of  fan 
who  complains  most  bit  f/'v  °r)  ?'  ^  ex" 
cuse.  We  must  face  this  fa%  he  went  on. 
"Two  stations  on  ic'  'ticarwav:  engths 
on  opposite  coasts,  >      ':I  lnter" 


\ 


when     they     use     1     ' 

watts." 

This  also   may  ap 

to  two  stations  only  50( 
mires    ttl_.     - 

Downey     exp 

difficulty  with  inert; 

power. 

"On  the  other  hai. 
he  pointed  or 
extend  the  scope  oi 
stations     tremendoi 
it  overcomes  static 
siderably;     it     will 
doubtedly  improve  S 
mer-time    and    prob 
daylight       transmis 
and  will  decrease  fa< 
This  means  a  lot  to  Uiris- 
all  over  the  country, 
will  be  able  to  pick  up 
more  stations,  and  even 
more    to    the    small    __u 
owners    who    previously 
got    only    a    very    few 
neighboring  stations,"  he 
concluded. 

The  nine  B  stations  now  authorized  to     small     territory,     compared     with     the 
operate  at  over  1000  watts,  with  their  pow-     great  expanses  of  the  United  States.     It 


The  map  showing  the  first  distribution  of  super-power  broadcast- 
ing stations  throughout  the  country.  Note  that  no  two  are  close  enough 
to  seriously  interfere  with  each  other.  KCO  and  KFI  may  prove  ex- 
ceptions, for  they  are  not  very  far  apart,  but  Government  officials  assure 
radio  fans  the  air  will  not  be  congested  by  the  strong  stations. 


er  and  wavelengths  are  listed  as  follows: 

Wave- 
Power-     length 
Station  Owner  Location  watts    meters 

WEAF    A.  T.  &T.  Co.... New  York,  N.  Y 2000  492 

KFI        Anthony,  E.  C.  .  .Los  Angeles,  Calif 1500  469 

KYW      Westinghouse  Co.  Chicago.  Ill 1500  535 

WBZ      Westinghouse  Co.  Springfield,  Mass 1500  333 

KGO       General  Electric    Oakland,  Calif 2000  300 

WGY      General  Electric    Schenectady,  N.  Y.        1500  380 
KFKX    Westinghouse        Hastings,  Neb.  1500  288 

WOC      Palmer  School       Davenport,  Iowa 1500  484 

WTAM  Willard  Bat.  Co.  Cleveland,  Ohio 1500  390 

It  is  understood  that  there  are  eight 
more  stations  contemplating  an  increase 
of  power  to  1500  watts.  Two  of  them 
ordered  5KW  sets  from  the  Western 
Electric  Co.  They  are:  the  Zion  Insti- 
tute station  in  Illinois,  WCBD,  and  the 
Crosley  Co.,  at  Cincinnati,  WLW. 
Others  reported  as  planning  to  install 
higher- power  sets  are:  WSAI,  the  U.  S. 
Playing  Card  Co.,  at  Cincinnati;  WCCO, 
Washburn- Crosby  Co.,  at  Minneapolis; 
KOA,  the  General  Electric  Station  at 
Denver;  KPO,  Hale  Brothers,  at  San 
Francisco;  WEAY,  the  Iris  Theatre,  at 
Houston,  Texas;  WLS,  Sears  Roebuck, 
Chicago,    and    WTAS,    Chas.    Erbstein, 


is  hoped  that  the  British  super-station 
will  carry  programs  to  crystal-set  owners 
within  a  radius  of  100  miles,  which  is 
something  for  this  type  of  fan  to  look 
forward  to  indeed.  France  has  a  20 
KW  station  in  operation. 

Here  in  the  U.  S.  A.,  officials  and  most 
fans  are  pleased  with  the  development  of 
higher  powered  broadcasting  and  look 
for  better  transmission  and  reception 
throughout  practically  every  state  of  the 
Union. 

Broadcasting  will  not  become  all 
high-powered,  however;  some  stations, 
like  WHAZ  at  Troy,  are  satisfied  with 
500  watts.  WHAZ  claims  the  long-dis- 
tance record  of  10,000  miles  and  reports 
regular  reception  in  thirty-two  states — 
the  British  Isles  and  Europe.  There 
will  continue  a  need  for  medium  sized 
and  even  purely  local  broadcasters,  and 
certainly   there   is  room  for  all  types. 


What's  Going  on 

"V^7"HAT     Secretary     Hoover 


and    his 
radio    force    is    trying   to    do    with 


individual  and  exclusive 
air   route. 

Developments  in  the 
past  year  had  shown 
that  many  stations  were 
reaching  a  position  in 
type  of  programs,  terri- 
tory covered  and  relia- 
bility of  equipment, 
which  made  it  desirable 
to  grant  them  exclusive 
wavelengths  and  more 
power  in  the  interests 
of  high-class  programs 
and  public  service.  This 
was  done  gradually  and 
fifty-seven  B  stations 
were  on  the  air  when  the 
conference  met,  besides 
which  about  twenty 
more  had  applied  or 
were  preparing  to  ask 
for  a  class  B  status. 
After  considerable  delib- 
eration, the  conference 
laid  out  a  plan  for  alloca- 
tion which  would  pro- 
vide forty-seven  separate  channels  for  dis- 
tribution among  the  class  B  stations,  some 
few  of  which  would  have  to  use  the  same 
wavelength.  Distance  and  time,  it  was 
believed,  would  make  this  practical. 

But  the  class  B  applications  began  to 
increase,  and  when  the  field  representa- 
tives of  the  Department  tried  to  argue 
with  the  owners  of  high-powered  stations 
to  split  time  and  shift  their  channels, 
difficulties  increased  materially.  The 
original  conference  plan  had  to  be  aban- 
doned. 

During  the  past  three  months,  the 
radio  experts  of  the  Department  of  Com- 
merce have  tried  out  several  other  plans 
for  increasing  the  number  of  channels 
in  the  band  alloted  to  the  B  stations, 
but  to  date  they  have  arrived  at  no 
practical  scheme  which  insures  a  satis- 
factory arrangement  between  the  broad- 
casters and  the  fans. 

"C"  Stations  Gone 

HPHF.Y  have  eliminated  the  old  Class 
-*-  C  stations  which  have  carried  on 
on  the  360  meter  wave.     The  others  have 


Elgin,  111. 

In  case  these  stations  apply  for  licenses  the    wavelengths   in   the   broadcast   field  either  transferred  to  Classes  A  or  B,  or 

and  are  O.  K.'d  by  the  Department,  there  seems   to   be   a   mystery   to   many   fans,  dropped  out.     No  more  Class  C  stations 

will     soon     be     seventeen     high-powered  despite    considerable     comment     in     the  are    being    licensed.      This    leaves    only 

broadcasters    on    the    air.      About    eight  Press  each  day-      Briefly,  he  is  trying  to  two   classes   of   broadcasters,    except   for 

more  stations  are  said  to  have  planned  improve  conditions  in   the   broadcasting  two    stations    carrying    on    experiments 

additional   power,    but   their   names  are  traffic,     and    has    put    every    available  under  what   is  termed   Class   D,   or  de- 

not  available.  channel  in   use.  velopment    licenses. 

v,     Pnwpr  „*  ->cftft  TVottv  When  the  Third  Nationa.  Radio  Con-  The  real  problem  before  the   Depart- 

Nrso  rower  at  tow    watts  ference    met    in    Washington    last    Octo-  ment  of  Commerce  concerns  redistribut- 

O   station   has  yet   applied   for   2500  ber,  a  plan  |for  the  reallocation  of  wave-  ing    the    Class    B    wavelengths    without 

watts,    and    no   actual    super-power  lengths  in  the  whole  field  of  radio  trans-  making  the  interference  worse  than  it  is 

broadcasting  license  is  on   file,   although  mission   was  proposed,  chiefly  in   an   ef-  today.    ' 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour         1 1 


Penetrating  Through  the  "Locals 


From  the  rear.  Two  ordinary  low  loss  three  circuit  couplers  and  two  low  loss  condensers  form  the  tuning  elements  of  this  five 
tube  receiver.  Wide  spacing  for  reduced- losses  is  a  noteworthy  feature  and  explains  the  large  size  of  the  set.  There  aren't  many  parts 
and  it's  easy  to  see  where  they  are  placed. 


RADIO  reception 
may  easily  be  di- 
vided into  two 
main  sections — local  and 
distant.  Conditions  con- 
ducive to  both  are  not 
necessarily  the  same, 
and  each  branch  of  reception  finds  condi- 
tions not  met  in  the  other.  Generally 
speaking,  local  reception  predominates 
and  as  far  as  city  dwellers  are  concerned, 
ordinarily  prevents  much  DX  listening 
until  the  nearby  stations  sign  off.  . 

A  receiver  capable  of  penetration 
through  local  opposition  is  more  or  less 
of  a  rarity,  just  because  such  a  receiver 
is  rather  difficult  to  tune  and  is  so  very 
sharp  in  its  dial  settings  that  it  is  not  a 
simple  matter  to  set  the  dials  just  right 
even  for  locals.  Therefore,  it  seemed  to 
me  that  some  sort  of  change-over  switch 
"which  would  very  greatly  sharpen  the 
tuning  when  DX  reception  through 
locals  is  desired  would  meet  the  problem 
most  effectively. 

And  to  permit  of  good  distant  recep- 
tion, it  goes  without  saying  that  two 
stages  of  radio  frequency  are  requisite. 
To  permit  handy  tuning,  the  two-dial 
method  seems  superior  to  the  three, 
inasmuch  as  nature  saw  fit  to  endow  us 
with  but  two  hands  and  we  are  not  yet 
sufficiently  dexterous  with  other  ap- 
pendages to  call  upon  them  to  twist  a 
third  control.  Therefore,  the  penetrator 
includes  a  stage  of  tuned  radio  frequency, 
a     stage     of     transformer-coupler     radio 


A  Double  Duty  Set— Twice 
Tuned andTw ice  Regenerative 

By  BRAINARD  FOOTE 


frequency,  a  detector  and  two  stages  of 
audio — five  tubes  in  all.  To  yield  the 
very  best  of  sensitiveness,  a  regenerative 
control  is  embodied  in  both  the  radio 
frequency  tuned  circuit  and  in  the  de- 
tector. 

nPO  SUIT  these  specifications,  two 
J-  standard  three  circuit  tuners  or 
couplers  are  employed;  one  to  tune  the 
R.  F.  amplifier  and  another  for  the 
detector.  In  each  case  it  is  necessary 
to  reduce  the  number  of  turns  on  the 
tickler  coils  to  about  15  turns,  although 
otherwise  the  instruments  are  used  as 
manufacturerd.  It  is  not  essential  that 
any  particular  style  of  coupler  be  selected, 
so  long  as  the  low  loss  type  of  construc- 
tion is  adhered  to.  The  primary  should 
have  approximately  six  turns  of  fairly 
heavy  wire  and  the  secondary  about  45 
to  50,  depending  somewhat  upon  the 
size  of  variable   condenser  called   for. 

The  views  of  the  outfit  reveal  an  un- 
usually large  size  of  panel  and  cabinet — 
possibly  a  drawback  on  account  of  the 
increased  cost  of  these  parts.  The  choice 
of  so  large  a  layout  was  made  following 
tests    of    spacing    between    instruments 


made  throughout  the 
recent  transatlantic 
broadcast  tests.  With 
couplers  close  to  the 
condensers  and  fairly 
near  each  other,  although 
at  right  angles,  volume 
from  the  stations  across  the  water  was 
fair,  but  with  much  wider  separation 
the  losses  of  various  sorts  were  so  re- 
duced that  very  pleasing  results  were 
obtained  from  English,  French  and 
Spanish  stations.  KHJ's  transmission 
was  followed  in  the  same  manner  (in  a 
location  near  New  York)  and  improved 
results  always  followed  when  the  in- 
struments were  spread  far  apart. 

The  front  panel  shows  quite  well  just 
how  the  various  instruments  are  situ- 
ated. Along  the  bottom  are  four  rheostat 
controls,  the  first  for  the  two  R.  F.  tubes, 
the  second  for  the  detector  and  the  other 
two  for  the  two  stages  of  audio.  Between 
them  are  three  jacks,  for  headphones; 
one  stage  for  local  loud  speaker  work 
and  two  stages  for  DX  loud  speaker 
work.  The  rheostats  are  all  included 
to  give  100  per  cent  flexibility  of  control. 


Main  Tuning 

TUST  above  these  and  at  the  center  is 
"  a  battery  switch,  whereby  all  tubes 
may  be  turned  off  without  necessitating 
changes  in  the  rheostat  dials,  these  al- 
ways being  left  at  the  best  operating 
points.  The  two  large  dials  control  the 
two  variable  condensers  by  which  tuning 


12        RADIO  AGE  for  M  arch,  1925 

is  accom- 
plished.  These 
ought  to  be  of 
the  vernier 
type  unless 
there  are  vern- 
ier attachments 
on  the  con- 
densers. Above 
each  tuning 
dial  is  the  tick- 
ler dial  for  the 
particular 
coupler  tuned 
by  the  con- 
denser under- 
neath. And  be- 
tween the  tick- 
ler knobs  is 
found  the  most 
important  feat- 
ure of  the  set 
in  one  respect: 
the  penetrator 
switch.  This 
is  a  double  pole 
double  throw- 
jack  or  anti- 
capacity  switch 
and  it  is  con- 
nected so  as  to 
reduce  the  num- 
ber of  turns 
not  only  in  the 
antenna  coup- 
ler but  in  the  detector  coupler  primary 
winding  as  well.  Ordinarily,  low  loss 
three  circuit  couplers  are  constructed 
with  a  six  turn  primary  winding.  With 
the  switch,  these  primary  coils  are  tapped 
at  the  second  turn  so  as  to  change  to  a  two 
turn  primary  in  each  case  and  in  that  way 
gain  a  remarkable  degree  of  selectivity. 

By  having  the  two  coupling  settings, 
we  are  enabled  to  use  the  6-6  setting  for 
local  reception,  the  2-2  setting  for  DX 
reception  through  locals,  and  the  6-6 
setting  for  DX  reception  when  the  locals 
sign  off  the  air.     Of  course,  greater  vol- 


The  Magazine  of  the  Hour 


Front  panel  of  the  Penetrator.  The  four  rheostat  dials  aren't  touched  once;  they 
are  set,  since  the  battery  switch  turns  tubes  on  and  off.  Two  large  dials  accomplish  the 
tuning,  and  smaller  ones  above  them  control  sensitiveness  when  DX  is  wanted.  A 
switch  alters  the  coupling  in  two  places  to  bring  great  selectivity  for  DX  reception  through 
local   stations. 


ume  is  to  be  had  with  the  6-6  position 
of  the  penetrator  switch,  but  on  the  2-2 
setting  it  is  possible  to  hear  dozens  of 
distant  stations  through  the  locals  that 
would  never  be  gotten  at  all  with  any 
receiver  of  average  coupling.  And  when 
the  locals  have  finished  for  the  evening, 
it  is  a  simple  matter  to  "flop"  the  switch 
over  the  other  way  and  receive  the  DX 
fellows  with  much  more  volume  and  with 
greater  ease  of  dial  adjustment. 

The  alteration  in  coupling  has  no 
effect  whatsoever  on  the  dial  setting  of 
the   condenser   tuning   the    detector   cir- 


and  again. 


cuit,  so  that 
the  settings  of 
this  dial  should 
be  "logged"  for 
reference.  The 
dial  readings  of 
the  other  con- 
denser change  a 
half  degree  or 
so  when  the 
switch  is  moved 
across,  but  they 
agree  so  very 
closely  anyway 
that  the  set- 
tings of  one 
dial  are  suffici- 
ent for  tuning. 
In  the  case  of 
the  detector 
dial,  the  set- 
tings can  be 
read  to  half  a 
degree  or  even 
less  if  one  wish- 
es and  the  elim- 
ination  of  a 
third  tuning 
dial  or  a  2  stage 
R.  F.  outfit 
greatly  simpli- 
fies the  matter 
of  dial  listing 
and  tuning  for 
a    station   time 


In  the  Country 


"D  EADERS  of  RADIO  AGE  who  are 
-*-  *•  not  included  in  urban  populations 
where  the  DX  local  problem  isn't  so  acute 
may  be  interested  in  the  value  of  the 
penetrator  switch  to  them.  In  a  location 
150  miles  south  of  Washington,  D.  C,  in 
Virginia,  the  penetrator  was  installed  with 
a  6  by  2  foot  wire  screen  ground  and  a  100 
foot  antenna  about  25  feet  high.  In  a  few 
evenings,  over  seventy  stations  were  listed 
(Turn  to  page  65 ) 


Note  how  the  penetrator  switch  changes  coupling  from  6  turns  to  2  turns  in  both  coupler  primary  coils  and  how  the  tickler  feed-back 
is  accomplished  in  both  radio  frequency  amplifier  and  detector.     Hard  tubes  are  employed  all  the  way  through. 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour         13 


€[A  Receiver  That  Will  Serve  for  Years 


Figure  1.  A  rear  view  of  the  seven-tube  super- 
heterodyne is  shown  below.  The  simplicity  of  the 
wiring  and  layout  is  evident.  An  approximate  layout 
is  all  that  the  builder  need  adhere  to. 


Embodying  the  Latest  in  Radio  in 

A  7'tube  Superheterodyne 


DURING  the  past  year  and  a  half 
the  super-heterodyne  receiver  has 
come  in  for  an  ever-increasing 
amount  of  justly  deserved  popularity,  for 
there  is  no  question  but  what  this  re- 
ceiver is  the  most  satisfactory  system 
ever  developed  for  broadcast  reception. 

Since  the  presentation  of  the  first 
constructional  articles  on  broadcast  super- 
heterodynes, many  developments  have 
taken  place  and  the  latest  type  of  super- 
heterodyne bears  very  little  resemblance 
to  its  predecessors  of  a  year  or  two  ago. 
The  reasons  for  this  are  only  the  reasons 
for  the  gradual  improvement  which 
takes  place  in  any  type  of  engineering 
equipment  during  a  period  of  years.  In 
this  case,  developments  have  taken  place 
very  rapidly,  for  a  few  years  ago  little  or 
nothing  was  known  about  practical  super- 
heterodyne designs  and  the  method  of 
building  each  section  of  the  receiver  in 
the  most  efficient  possible  manner. 

Re-radiation  and  consequent  inter- 
ference with  neighboring  receivers  has 
been  one  of  the  points  upon  which  the 
super-heterodyne  receiver  has  been  con- 
demned by  a  great  number  of  enthusiasts, 
many  of  them  possibly  having  had  no  prac- 
tical experience  with  this  receiver.  In  a 
number  of  tests  conducted  to  determine 
to  what  extent  this  radiation  was  detri- 
mental to  neighbors'  reception,  several 
conditions  were  noticed. 

In  one  of  the  tests,  two  super-hetero- 
dyne   receivers    were   set    up    operating 


By  McMURDO  SILVER 

approximately  fifty  feet  away,  each  on  a 
loop  and  each  tuned  to  the  same  station. 
No  trouble  was  experienced  due  to  radia- 
tion from  either  receiver  when  the  sets 
were  in  a  condition  where  the  signal  was 
heard.  If,  however,  the  oscillator  of  one 
receiver  was  set  directly  upon  the  wave- 
length of  the  transmitting  station  (a 
condition  in  which  a  signal  could  not 
be  heard  on  this  particular  set),  a  slight 
amount  of  interference  was  noticed  on 
the  other  receiver.  As  soon  as  the 
neighboring  oscillator  was  moved  off 
the  signal  wavelength  and  back  into  the 
adjustment  where  it  produced  the  neces- 
sary beat,  no  interference  was  noticed. 

In  another  test,  a  super  was  connected 
to  a  seventy-five  foot  antenna  and  a 
6  tube  receiver  of  a  rather  sensitive  type 
was  set  up  in  conjunction  with  its  loop 
twenty-five  feet  away.  About  the  same 
conditions  were  noticed;  when  the  oscilla- 
tor was  in  resonance  with  the  antenna  cir- 
cuit, radiation  was  evident,  but  when  it 
was  set  at  a  position  to  produce  the  de- 
sired beat  with  the  station  heard,  no 
radiation  was  noticed. 

Then  the  antenna  coupling  of  the  super 
was  loosened  up  to  a  point  where  only 
one  turn  was  used  between  the  antenna 
and  ground.  The  signals  retained  prac- 
tically their  original  intensity,  but  the  radi- 
ating effect  of  the  super  was  cut  to  a  very 
great  extent;  in  fact,  down  to  a  point 
where  it  could  barely  be  noticed,  using 
head  phones  on  the  output  of  the  r.f.  set. 


From  these  and  other  tests  the  writer 
feels  it  safe  to  conclude  that  the  radiat- 
ing proclivities  of  the  super-heterodyne 
are  very  much  over-rated,  and  at  best 
they  are  only  disturbing  when  the  oscil- 
lator and  loop  circuits  are  in  resonance. 

The  average  experimenter,  when  un- 
dertaking the  construction  of  a  super- 
heterodyne receiver,  wishes  to  feel  that 
he  is  building  a  receiver  which  embodies 
not  only  the  very  latest  advances  in  the 
art,  but  which  will  continue  to  give 
results  in  excess  of  other  receiving  sys- 
tems over  a  period  of  several  years, 
since  it  is  safe  to  expect  no  radical 
developments  in  radio  for  some  time  to 
come — despite  the  propaganda  to  the 
contrary. 

The  Last  Word 

HPHE  receiver  to  be  described  may 
■*-  safely  be  said  to  be  the  latest  word  in 
super-heterodyne  designs  and  embodies 
to  perfection  the  five  prime  receiver 
requisites  of  sensitivity,  selectivity,  ease 
of  control,  quality  of  reproduction  and 
simplicity  of  assembly. 

Every  worth-while  designed  feature 
found  in  equipment  such  as  is  supplied 
to  the  Signal  Corps,  Navy  Department, 
has  been  recognized  and  utilized  to  best 
advantage. 

The  receiver  itself  embodies  seven 
tubes — a  regenerative  first  detector  and 
oscillator,  two  intermediate  frequency 
amplifiers  and  second  detector  and  two 


14        RADIO  AG  v 


Figure  2.  Wiring  diagram  for  the 
Mr.  Silver  in  the  accompanying  article, 
the  tubes. 


new    type    of  super-heterodyne  as  described  by 
Note  that  only  one  rheostat  is  used  to  control 


The  Magazine  of  the  Hour 

audio  frequency  amplifiers,  and  will 
cover  a  wavelength  range  of  from  200 
to  600  meters  with  a  distance  range 
depending  upon  individual  conditions  of 
from  500  to  5,000  miles  for  loud  speaker 
reception. 

The  seven  tubes  used  in  the  outfit 
may  be  either  dry  cell  or  storage  battery 
tubes  of  any  standard  type  on  the  market 
and  are  employed  in  such  a  manner  as  to 
give  maximum  efficiency  in  each  circuit. 
For  various  reasons  the  use  of  the 
second  harmonic  principle  or  other 
systems  of  combining  the  functioning  of 
the  first  detector  and  oscillator  in  one 
tube  will  generally  result  in  a  decrease  in 
results  about  equivalent  to  the  elimina- 
tion of  the  one  tube  that  is  saved  by  such 
a  system. 

The  first  detector  circuit,  being  regen- 
erative, permits  of  maximum  sensitivity 
and  selectivity.  The  sensitivity  of  this 
set  as  a  whole  might  be  compared  to 
other  super-heterodyne  systems  employ- 
ing a  non-regenerative  first  detector 
circuit,  as  one  would  compare  a  non- 
regenerative  tuner  to  a  regenerative 
tuner.  The  intermediate  frequency  am- 
plifier represents  a  real  step  ahead  in 
super-heterodyne  designing,  since  but 
two  stages  are  employed. 

The  transformers  function  at  a  fre- 
quency of  approximately  60  kilocycles  or 
5,000  meters,  but  this  will  vary  somewhat 
with  the  tubes.  They  are  of  the  iron 
core  type  with  a  sharply  tuned  air-core 
output  transformer,  and  give  a  voltage 
amplification  of  from  1}^  to  3  3^  times 
that  of  any  other  transformer  now  avail- 
able. Two  stages  of  amplification  with 
these  transformers  are  entirely  sufficient 
to  get  down  to  the  noise  level  under 
extremely  favorable  conditions,  and  the 
use  of  a  third  stage  would  not  be  war- 
ranted, especially  as  it  would  give  practi- 
cally no  increase  in  amplification.  The 
second  detector  and  radio  frequency 
amplification  employ  combination  cir- 
cuits and  will  be  found  to  give  extremely 
satisfactory  results  from  the  standpoint 
of  amplification  and  quality  of  reproduc- 
tion. 

It  is  suggested  that  if  the  builder  de- 
sires to  make  the  set  with  the  absolute 
assurance  that  he  cannot  do  better, 
it  wo'uld  be  advisable  to  employ  instead 
of  the  transformer  unit,  a  combination  of 
two  60  k.  c.  intermediate  transformers 
and  one  60  k.  c.  filter  transformer.  These, 
however,  should  only  be  of  a  type  sup- 
plied with  laboratory  amplification  curves, 
the  filter  being  tuned  to  the  peaks  of  the 
other  two  transformers  and  supplied 
with  the  exact  condensers  for  tuning  it 
which  have  been  used  to  get  the  peak 
shown  on  its  curves.  The  use  of  these 
transformers  with  their  individual  am- 
plification curves  insures  a  uniformity 
which  cannot  be  approached  by  un- 
charted transformers  and  reduces  the 
variation  in  their  operating  characteris- 
tics to  the  extremely  low  value  of  1  % 
compared  to  a  variation  of  from  5%  to 
15%    with    uncharted    transformers. 

What  About  Results? 
'  1 1rIE  average  fan  is  interested,  when  all 
-"■  is  said  and  done,  in  the  results  that  he 
may  expect  from  the  set,  and  reports  on 
this  design  have  been  more  than  favor- 


RADIO  AGE  for  March,  1925 


able.  One  builder  in 
New  York  state  re- 
ceived KGO  (Oak- 
land, California),  at  a 
distance  of  2,800 
miles  with  loud 
speaker  volume  on  an 
18  inch  loop,  every 
night  that  KGO  was 
in  operation  for  two 
consecutive  weeks. 
The  set  he  used  em- 
ployed seven  199  dry 
cell  tubes.  These  re- 
sults are  exceptional, 
and  speak  volumes 
for  the  set,  although 
it  must  be  realized 
that  they  were  de- 
pendent to  a  great 
extent  upon  location.  However,  sets  of 
this  type  throughout  the  country  have 
given  extremely  satisfactory  results  in 
practically  all  cases,  bringing  in  oppo- 
site   coasts,     especially    in    Chicago. 

One  set  used  by  Captain  Irwin 
brought  in  stations  on  both  coasts  and 
Canada  with  loud  speaker  volume  on  a 
small  loop,  while  being  located  in  Las 
Vegas,  New  Mexico.   So  much  for  results. 

The  set  itself  may  be  used  with  either 
storage  batteries  or  dry  cell  tubes  with- 
out a  change  of  any  values  at  all  in  the 
circuit  or  assembly,  except  that  different 
sockets  will  have  to  be  used  for  different 
types  of  tubes.  The  results  will  be 
substantially  the  same  with  either  storage 
batteries  or  dry  cell  tubes,  although  dry 
cell    tubes    U.  9s    and    DV3s)    are 

recommended,  as  resu  its  will  be  the  same  as 
with    201A   tubes,    and    the    set  ; 

very  much  more  satisfactory  to  ha       j. 

The  Materials 

THE    material    required    to    bujld    the 
set  is  as  follows,  and  will  cost  approxi- 
mately $64,  less  cabinet  and  accessories: 
2.   .0005   Low  Loss  condensers. 

moulded  dials,  tapered  knobs. 
!.    •■:  ~  Oh;  •  rheostat. 
1      ISO  or  400  Ohm  potentiometer. 
/  ated  top  binding  posts. 

1     Two  .   ~  jack. 

1     One  spring  . 

1  R.  F.  Transformer  Unit,  or  2  60 
K.  C.  charted  transformers  and  1  6G'K. 
C.  charted  filter 

1     Oscillator  coupler. 
Sockets. 

Audio   transformers. 
On-Off  switch. 
.5  Condensers. 
.00025   Mica  condensers  with  leak 


The  Magazine  of  the  Hon?        15 


2  RANGE  VOLT  Mi 
EXTERNAL  BEST 
FILAMENT     &  PU 


I  RANGE  VOLTMETED  ^Cn 
DETECTOR  OS  AMPLIFIED 
PLATE     VOLTAGE 


Figure  3.      The  above  diagram  shows  the  method  of  :  iring  th 
of  wiring  the  voltmeter  to  permit  of  reading  the  voltage  on  both  the  " 


VOLTMETER     RtSliTOR 


also  the  method 
battery. 


7 

2 

1 

3 

2 
clips. 

2     .002  Mica  condensers. 

1     .0075  Mica  condenser. 

1  .000045  Balancing 
condenser. 

1     5  megohm  Grid  Leak. 

1      1  megohm  Grid  Leak. 

1  7x24x3-16"  Bakelite 
panel. 

1  7x23j^"  Oak  Base 
Board,  Bus-Bar,  spaghetti, 
screws,  nuts,  solder,  lugs. 

The  tools  required  to 
assemble  this  set  will  be  a 
pair  of  pinchers,  screw 
driver,   soldering   iron,   one 


drill   with   drills,  and  countersink, 
drilled  and  engraved  panel  is  pu; 
this   will   be 

A  front   view  of   th  oiiown    in 

Figure  4,  with  a  rf  :  assembly  view  in 
Figure  1.  The  voltmeter  shown  may 
be  used  or  it  may  be  omitted  as  desired. 
Its  only  advantage  is  that  it  permits 
resetting  the  tubes  at  the  same  operating 
point  each  time  the  set  is  used  and  acts 
as  a  check  on  the  condition  of  the  bat- 
teries. The  meter  shown  is  for  both  A  and 
B  batteries.  A  small  key  switch  is  shown 
below  it  and  the  spool  attached  to  this 
switch  is  the  voltmeter  multiplier  which 
is   used  when  reading  B-battery  voltage. 

Laying  the  Panel 

T^HE  panel  should  be  laid  out  in  ac- 
-*-  cordance  with  the  drawing  and  all 
holes  drilled  and  countersunk.  If  the 
builder  desires,  it  may  then  be  grained  by 
rubbing  in  one  direction  only  with  fine 
sand  paper  and  oil  until  all  traces  of  the 
polished  finish  have  been  removed.  The 
condenser,  rheostat,  potentiometer,  bind- 
ing posts,  jacks,  etc.,  should  be  attached 
to  the  panel  as  shown  in  one  of  the 
figures.  All  parts  should  be  screwed  on 
the  baseboard  as  shown,  using  1-2"  or 
3-4"  wood  screws,  the  holes  being  first 
started  with  a  No.  45  drill  to  facilitate 
proper  location  of  the  parts. 

Each  individual  piece  of  equipment 
should  be  checked  over  carefully  to  make 
sure  that  all  nuts,  screws,  etc.,  are  tight 
and  that  all  springs  on  sockets  are  bent 
up  and  are  making  contact.  If  this  is 
done,  it  will  save  trouble  later  on  after 
the  set  has  been  completely  wired.  Lugs 
should  be  attached  to  all  binding  posts  or 
terminals,  to  which  the  wiring  should  be 
soldered.     The  wiring  may  be  done  with 


Figure   4.      The   complete    laboratory    model    of    Mr. 
Silvers'  super-heterodyne. 


i  Dus-bar  or  with  magnet 
wire,  say  No.  20  or  22,  with  the  insula- 
tion scraped  off,  run  in  spaghetti.  The 
bus-bar  wiring  makes  a  neater  job,  but 
is  a  little  more  difficult.  Spaghetti  is  rec- 
ommended throughout  if  magnet  wire  is 
used,  but  need  only  be  employed  in  bus- 
bar wiring  where  there  is  danger  of  wires 
coming  in  contact  and   short-circuiting. 

If  a  well-tinned  iron  is  used  and  each 
wire  and  lug  tinned  separately  before 
endeavoring  to  make  a  joint,  little  or  no 
trouble  will  be  experienced.  A  very 
small  amount  of  non-corrosrve  soldering 
paste  will  help  materially,  and  will  tend 
to  make  very  much  smoother  joints  than 
if  only  rosin  core  solder  were  used.  In 
wiring  the  set,  the  panel  with  its  instru- 
ments should  be  wired  first  and  then  all 
wires  put  in  place  on  the  baseboard 
before  the  panel  is  actually  screwed  to 
it.  This  will  leave  only  a  few  wires  to  be 
run  between  the  panel  and  the  base- 
board and  will  simplify  this  job  very  much. 
If  the  builder  wishes  to  make  the 
oscillator  coupler,  it  may  be  constructed 
by  winding  the  grid  and  plate  coils  on 
a  2  1-4"  Bakelite  tube  2"  long,  each 
section  being  wound  with  about  thirty 
turns  of  No.  30  D.  S.  C.  wire. 

The  rotor  consists  of  a  1J^"  tube,  1" 
long,  wound  with  18  turns  of  the  same 
wire,  and  should  be  located  in  the  center 
of  the  stator  tube  and  arranged  so  that 
it  may  rotate.  If  it  is  desired  to  use 
other  transformer  instead  of  the  trans- 
former unit,  a  good  type  of  charted 
long  wave  iron  core  transformer  with  a 
filter    may    be    employed. 

If   this   is   done   the    left    hand   trans- 
former   in    the    diagram    will    have    its 
terminals  corresponding  to  the  numbers 
shown    as   follows:      Number    2    will    be 
"P";    Number    1     will     be 
"B-plus";    Number   3   will 
be   "G";  Number  6  will  be 
"A-Minus."      The     middle 
transformer   will  have  four 
equal  to  "P"  five  equal  to 
"G,"     six     equal     to    "A- 
Minus"    and     8    equal    to 
"B-plus."     The  right  hand 
or    filter    transformer    will 
have  ten  equal   to  "G,"  7 
equal   to   "P,"   nine   equal 
to  "A-minus,"     and     eight 
equal  to  B-plus.     The  .0075 
condenser      shown      across 
( Turn  to  page  58) 


16 


RADIO  AGE  fo    M  fch,  1925 


The  Magazine  of  the  Hour 


Dorit  BLAME  the  HOOKUP 

By  ROSCOE  BUNDY 


No  set  will  work 
if  the  tubes  aren't 
right.  Some  tubes 
are  better  as  R.  F. 
amplifiers,  some 
as  detectors  and 
others  as  ampli- 
fiers. Change 
them  around  till 
you  find  where 
they   work    best 


In  Most  Cases  the  Fault  Lies  in  the  Lack 
of  Proper  Workmanship  or  in  Poor  Materials; 
Bad   Soldering   Leads   in    Causing   "Flukes" 


THERE  is  always  a  tendency  toward 
charging  up  all  troubles  to  the 
hookup,  but  in  99  cases  out  of  a 
hundred  the  fault  will  be  found  due  to 
errors  in  construction  or  to  defective 
materials.  Since  1922  the  writer  has 
serviced  some  500  home  built  sets  and 
in  practically  all  cases  workmanship, 
or  rather  lack  of  workmanship,  lay  at 
the  bottom  of  the  difficulty. 

For  those  interested  in  statistics  it 
will  be  thrilling  to  note  that  there  is 
only  one  man  out  of  one  hundred  who 
understands  soldering,  and  as  soldering 
is  the  basis  of  a  successful  receiver,  this 
deficiency  stands  at  the  head  of  the 
trouble  list.  Some  of  the  amateur- 
soldered  joints  that  I  have  seen  would 
give  a  telephone  man  acute  hysterics. . 
Joints  partly  soldered  with  a  cold  iron, 
joints  stuck  together  only  by  the  flux, 
soldering  attempted  without  any  flux  at 
all,  joints  soldered  with  acid  flux,  etc., 
etc.,  etc. 

In  the  first  place,  we  must  supply 
sufficient  heat  by  means  of  the  soldering 
iron  to  melt  the  solder  to  the  point  where 
the  metal  is  completely  fluid  and  flows 
as  readily  as  water.  Heating  the  solder 
with  a  cool  iron  to  a  stiff  paste  will  not 
produce     an     electrically     perfect    joint. 


Secondly,  the  parts  to  be  joined  must  be 
heated  up  before  solder  is  applied  by 
simply  resting  the  soldering  iron  on  the 
parts.  If  the  lugs  or  wires  are  cold, 
they  will  chill  the  solder  and  thus  prevent 
adherence.  Large  screws  and  nuts 
require  considerable  heating  before  they 
are  hot  enough  to  amalgamate  with  the 
solder.  A  cool  iron  is  only  capable  of 
melting  the  flux  and  not  the  solder 
proper;  thus  with  a  cool  iron  we  tend  to 
stick   the   parts   together   with    flux. 

Next  in  importance  comes  cleanliness. 
Solder  will  not  adhere  to  dirty,  rusty, 
greasy  surfaces.  The  surfaces  of  the 
metal  must  be  scraped  bright  with  a 
scraper  or  file  and  must  not  thereafter 
be  touched  with  the  fingers  until  the 
soldering  is  completed.  Finger  marks 
leave  greasy  spots  which  will  not  take 
solder.  In  addition  to  a  clean  surface 
and  the  proper  heat  we  will  require  some 
fluid  that  will  chemically  remove  all 
dirt  not  removed  by  the  scraping  and 
which  will  reduce  all  exides  that  may 
form  after  the  scraping.  Such  materials 
are  known  as  "Fluxes"  and  are  represented 
by  rosin,  sal  ammoniac,  and  similar 
compounds  which  readily  dissolve  many 
of  the  metallic  oxides.  The  best  flux 
for  soldering  brass  and  copper  parts   is 


plain  pure  rosin.  Acids  should  be 
carefully  avoided  as  they  draw  moisture 
into  the  connection  and  are  responsible 
for  many  partial  short  circuits  as  well  as 
producing  a  noisy  circuit. 

Don't  Waste  Flux 

ONLY  enough  flux  should  be  supplied 
to  cover  the  surface  completely 
and  no  more.  An  excess  of  flux  makes 
a  dirty-looking  job  and  may  flow  into 
the  joint,  causing  an  open  circuit. 
Rosin  is  an  excellent  insulator,  hence 
if  it  gets  into  the  joint,  it  will  prevent 
electrical  contact.  So  much  flux  is  used 
by  many  beginners  that  the  wires  are 
simply  stuck  together  by  rosin  without 
the  solder  coming  into  contact  at  all. 
Such  joints  are  mechanically  weak  and 
may  be  detected  by  giving  the  wire  a 
good  shaking  after  the  solder  is  applied. 
If  the  wire  breaks  loose,  you  may  be 
sure  that  it  has  simply  been  stuck  on 
by  the  flux.  Don't  be  afraid  to  shake 
the  wires  well,  with  a  firm  grip.  Treat 
'em  rough. 

Next  on  the  soldering  subject  comes 

the  connections  made  to  fixed  condensers. 

Don't     make     any     solder     connections 

directly   to    fixed   condensers   in    such   a 

(Turn  to  page  68) 


RADIO  AGE  for  March,  1925  The  Magazine  of  the  Hour  17 

For  Coast-to-Coast  Reception — 

A  Compact  FIVE;  TUBE  SET 


Back  panel  view  of  the  "non-osciilaiing"  set  described  in  this  article, 
mounted  at  the  angle  shewn  to  prevent  of  interstage  coupling. 


The  coils  should  be 


A 


LMOST    daily    the    author    of    this  D      7_r    C'D  A  ATI/"    I—fOPIS'  I  AT  C  from    the    customary    whistle    or    sound 

article    has    been    approached    by  ./  *  *•  •*   J^'il  vix.  1  l\Jx    iN.1  iVO  produced  when  tuning  the  set  to  receive 

fans   in    quest   of   information   on     a  program.      It   is  absolutely   quiet  and 

how  to  construct  a  good  coast  to  coast  j_r           •                    r-v   t/-       O     .          £  lree   from    sending    out    on    the    air   the 

receiving  set,  which  is  not  too  complicated  llCrC   S     CI     D J\      C^€t     Of  troublesome   noise   produced   by   sets   of 

for  the  general  run  of  set-builders,   not  i          cr^                i    r\       r-i     <-p      ,  the  regenerative  type. 

too    expensive    for    the    average    pocket-  tllC      1  VLYXCCi  I\.  1     .    1  ^06         Construction    of   the   set    described   in 


book  and  not  as  big  and   bulky  as  the 
average  five-tube  receiving  set. 


this   article   is   reasonably   simple.      The 
placing   of    the    parts    proved    the    most 


This  was  by  no  means  an  easy  problem     frequency,    or    the    frequency    at    which     difficult  task  and  a  word  on  this  point 


to  solve.     However,  after  much  shopping     reproducers  (head  phones  or  loud  speak- 
and  not  a  little  engineering,  accompanied     ers)    will   respond.      This   feature   makes 


by  the  usual  disappointing  results,  the 
five-tube  "de-luxe"  receiver  to  be  de- 
scribed in  this  article  was  produced, 
giving  the  desired  range  and  volume  and 
mounted  on  a  panel  as  small  as  seven 
inches  by  eighteen  inches  at  a  total 
cost  of  only  §16.45,  including  a  fairly 
good  cabinet.  Accessories,  of  course, 
are  not  included. 


possible  the  reproduction  of  signals 
otherwise  too  weak  to  operate  a  detector 
tube  when  applied  directly  to  that  tube, 
thus  increasing  the  range  of  the  set  in 
proportion  to  the  radio  frequency  am- 
plification applied,  which  in  this  set  is 
two  stages. 

The     non-oscillating     feature     is     the 


will  not  be  amiss  at  this  time.  It  must 
be  borne  in  mind  that  the  inductive 
field  produced  by  radio  frequency  cur- 
rents, when  applied  to  coils  or  trans- 
formers, is  very  sensitive  to  interference, 
and  any  force  or  body  entering  upon  this 
field  will  induce  counter  currents  or 
variations  foreign  to  the  proper  func- 
tioning of  these  coils,  producing  very 
distressing  results  such  as  noise,  loss  of 
volume,    distortion    or   even    the    failure 


elimination    of    squeals    and    disturbing 

The  circuit  is  of  the  tuned  radio  fre-     noises    caused    by    the   tubes    oscillating  of  the  set  to  reproduce  signals  at  all. 

quency  type  and  is  non-oscillating.      A     when    too    much    current    is    applied    to         To  overcome  the  danger  of  such  inter- 

"DX    getter"    of    the    first    order,    with     the   filament.      This   circuit   is   also   free  ference,   the   parts  should   be   placed  so 


lots  of  volume  and 
producing  features 
similar  to  the  neu- 
trodyne  type  of  cir- 
cuit without  the 
troublesome  task  of 
neutralizing  or  bal- 
ancing the  set. 

Weak  Signals 
Amplified 

T>Y  TUNED  radio 
-*-*  frequency,  we 
mean  a  type  of  cir- 
cuit which  amplifies 
the  incoming  signal 
at  radio  frequency, 
before  it  is  applied 
to  the  detector  tube 
and  changed  to  audio 


Here's  a  front  view  of  the  panel  of  Mr.  Hobkins'  non-oscillating  radio  frequency 
receiver.  Note  the  lack  of  complicated  controls.  The  tuning  is  accomplished  by  the  three 
dials  and  the  remaining  control  regulates  volume.     It's  as  simple  as  it  looks,  too. 


that  the  magnetic 
or  inductive  field  of 
one  piece  will  not 
overlap  that  pro- 
duced by  another 
piece.  This  is  at- 
tained in  the  small 
space  available  in 
this  set  by  mount- 
ing the  radio  fre- 
quency transformers 
on  four  inch  centers 
and  each  on  an  angle 
of  about  sixty  de- 
grees, and  by  plac> 
ing  one  audio  fre* 
quency  transformer 
on  the  under  side  of 
the  shelf  and  the 
other  at  right  angles 


18 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


sum- 

METHOD  OF  HINDI NS. 
COILS  K/,7?-2,7?-3. 


*/is"  Voh/ELL- 

E"/G(/RE  Z  fiCOTTO/V    THK£*D 


C0IL 


SHsir 


Of 


/fO(/*ST£ D     CO/  L. 


TJ 

£AfO    ELECTION 
OF     COIL. 


/fH3S 


Figure  2.    Showing  method  of  fastening  coils  to  sub-panel.    In  the  upper  part  of  the 
drawing  is  shown  the  winding  of  the  wire  on  the  wooden  form. 


to  the  first,  and  on  the  top  side  of  the 
shelf,  the  latter  transformer  will  then 
be  at  or  nearly  at  an  angle  of  sixty  degrees 
from  the  radio  frequency  transformer 
(R-3)  thus  keeping  outside  of  the  field 
of  this  coil. 

Parts  to  Build  the  Set 

\  LL  of  the  parts  used  in  this  set  are 
-^*-  clearly  marked  with  a  designating 
letter  or  number  throughout,  and  on  the 
drawings,  in  order  to  better  enable  the 
builder  to  distinguish  properly  and. place 
each  part  in  the  circuit  and  to  more 
clearly  describe  them  in  the  following 
paragraphs. 

1  Composition  panel  7"xl8w  (A) 

3  Thirteen  plate  variable  condensers  (C-l,  C-2.  C-3) 
3  Three  inch  composition  dials  for  the  variable  condensers 
3  Radio  frequency  transformers  CR-1.  R-2,  R-3) 
(The  construction  of  these  transformers  is  described  in  this 
article.) 

5  201  type  tube  sockets  (M-l  to  M-5) 
1  25-ohm  rheostat  (R) 


2  Unmounted,  audio  frequency  transformers  (T-l,  T-2) 

(The  ratio  of  these  transformers  can  be  either  3,  4  or  5  to  1.) 

1  Two  circuit  jack  (P) 

1  Open  circuit  jack  (S) 

1  Mica  grid  condenser  and  grid  leak  mounting  ) 
capacity    .00025  mf. .  }  (GL) 

1  Tubular  grid  resistance  2  1-2  megohms 

6  Binding  posts  (A.  — ,  G,  A4-.  BD.  B4-) 

1  Wood  shelf  6  l-2"sl7  "(B) 

Terminals,  wood  and  machine  screws,  wire  solder  and  mis- 
cellaneous raw  material. 


It  would  be  well  to  secure  all  of  the 
parts  necessary  to  build  the  set  before 
starting.  Any  standard  piece  of  equip- 
ment will  suffice,  providing  it  is  not  too 
bulky.  However,  care  should  be  exer- 
cised in  buying,  as  a  cheap  piece  of  equip- 
ment sometimes  will  turn  out  to  be  rather 
expensive  in  the  end. 

When  the  parts  are  all  at  hand,  they 
should  be  placed  on  the  shelf  (B)  in 
the  relative  locations  shown  in  the  pic- 
tures of  the  set.  Be  careful  to  get  the 
coils  (R-l,  R-2,  R-3)  and  transformers 
(T-l,  T-2)  spaced  and  placed  on  angles 


so  that  they  will  not  fight  one  another 
as  just  described.  Next,  mark  the  holes 
for  mounting  the  parts  and  drill  the  shelf. 
The  same  procedure  will  take  place  with 
the  panel  (A)  and  the  necessary  holes 
drilled.  It  would  be  well  to  drill  the 
holes  for  the  shafts  of  the  three  con- 
densers (C-l,  C-2,  C-3)  about  three- 
eighths  of  an  inch  in  diameter  or  even  one- 
half  inch  to  prevent  these  shafts  from 
binding  against  the  panel  when  the 
condensers  are  mounted.  If  these  shafts 
should  bind,  it  would  cause  the  conden- 
sers to  turn  hard,  making  it  difficult  to 
tune  critically. 

The  shelf  can  then  be  mounted  to  the 
panel  by  passing  three  number  four 
round  head  wood  screws  through  into 
the  edge  of  the  shelf.  These  screws 
will  be  about  three-quarters  of  an  inch 
long.  We  will  now  set  the  shelf  and 
panel  aside  until  the  radio  frequency 
transformers  (R-l,  R-2,  R-3)  are  con- 
structed. 

Construction  of  R.  F.  Transformers 

'  I  ''HE  radio  frequency  transformers  to 
-*-  be  used  are  of  the  spider-web  type. 
The  ones  shown  mounted  in  this  set 
have  had  the  forms  or  frames  removed 
and  are  mounted  by  a  three-sixteenth 
inch  wood  dowell  pin  passed  through  the 
lower  part  of  the  coil  and  made  fast  with 
cotton  thread.  This  makes  a  truly 
low  loss  coil. 

If  desired,  the  coils  may  remain  on 
the  frames  and  be  mounted  in  a  like 
manner,  except  one  of  the  spokes  of  the 
frame  is  used  in  place  of  the  dowell  pin 
as  shown  in  Figure  2.  This  will  not 
make  a  low  loss  coil,  but  the  difference 
will  be  rather  slight  and  may  not  be 
noticed  if  the  balance  of  the  set  is  prop- 
erly assembled. 

One  seventeen-spoke  spider  frame  will 
be  required  for  each  coil  if  the  coils 
are  to  remain  upon  the  frame.  If  the 
'Turn  to  page  61) 


Wiring  diagram  of  the  "De  luxe"  receiver  described  in  this  article.  Note  the  location  of  the  ground  wire,  and  the  position  of  the 
filament  rheostat.  The  usual  potentiometer  has  been  left  out  of  this  circuit,  as  it  was  found  by  experiment  that  this  control  was  not 
necessary. 


RADIO  AGE/of  March,  1925 


The  Magazine  of  the  Hour         19 


INNER 


THE  interest  of 
the  radio  fan 
has  been  given 
mostly  to  more  effi- 
cient hook-ups,  and 
many  experts  have 
invented  circuits 
which  were  merely 
modifications  of  well 
known  hook-ups.  In 
most  cases  they  had 
only  the  disadvan- 
tage of  being  more 
complicated  than  the 
original  ones.  More 
recently  the  interest 
has  been  centered  on 
the  reflex  circuit 
which  affords  a  bet- 
ter utilization  of  the 
tubes,  their  efficiency 
being  increased  prac- 
tically  100  per  cent. 

The  advent  of  the 
double  grid  tube  must 
be  considered  as  im- 
portant an  achieve- 
ment as  the  reflex 
idea.  The  new  tube 
affords  a  means  of 
improving  greatly  the 
efficiency  of  the  re- 
ceiving set  and  of  re- 
ducing the  expense  by  enabling  one  to 
use  very  low  plate  voltage. 

The  internal  resistance  of  the  three- 
electrode  tube  which  limits  the  value  of 
the  plate  current  and  obliges  us  to  use 
a  high  positive  potential  on  the  plate,  is 
due  to  the  presence  of  a  cloud  of  electrons 
around  the  filament,  which  repell  the 
newly  emitted  electrons  which  have  not 
enough  velocity  to  reach  the  plate. 

It  will  be  understood  readily  that  the 
addition  of  a  grid  close  to  the  filament  and 
impressed  with  a  positive  potential  will 
neutralize    the    negative    charge    of    the 
cloud  of  electrons  and  thus  reduce  ma- 
terially the  internal  resistance  of 
the  tube.    This  modification  is  the 
only  difference  of  the  double  grid 
tube  with  an  ordinary  "audion." 

"The  Inner  Grid" 

IN  the  following  explanation, 
the  grid  closer  to  the  filament 
will  be  called  the  "inner  grid" 
and  the  other  grid  the  "control 
grid."  The  voltages  impressed 
on  the  inner  grid  and  the  plate 
were  only  12  volts,  the  voltage 
and  current  on  the  filament  being 
respectively  3.9  volts  and  .35A. 
Curves  of  Fig.  1  were  obtained 
under  these  conditions.  As  soon 
as  the  filament  is  lighted,  it  emits 
electrons.  These  carry  a  negative 
charge  of  electricity.  When  the 
voltage  of  the  control  grid  is 
between  50  and  35  volts  negative, 
a  certain  number  of  electrons  is 
attracted  to  the  grid,  which  is  12 


P0T£  CVRVE 


cojfrftoc 


amye 


GRID 


-  40    -zo 


+40 


The  above  chart  demonstrates  very  clearly  the  current  curves  of  the  double  grid  tube. 
These  curves  were  obtained  by  using  only  3.9  volts  to  heat  the  filament  with  only  12  volts  im- 
pressed on  the  plate  and  inner  grid.  The  current  consumption  of  this  tube  is  very  small,  only  .35 
amperes  per  ampere  hour. 


by  the  negative  field 
of  G  is  less  important, 
since  the  negative 
field  has  decreased  in 
intensity;  more  elec- 
trons go  to  the  inner 
grid  and  its  current 
increases  slightly. 

The  control  grid 
repells  all  electrons 
in  the  space  from  the 
inner  grid  to  the  plate 
so  that  we  have  no 
other  current  than 
the  increased  inner 
grid    current. 

How  Current  In- 
creases 


Using  Low  Voltage 

With  a  Double-Grid  Tube 

Use  of  Inner  Grid  Only  Helps  Cut  Resistance 
By  C.  R.  BLUZAT 

volts  positive.  We  know  that  opposite 
charges  of  electricity  attract  each  other, 
while  like  charges  repell  each  other. 

The  high  negative  field  has  the  effect 
of  weakening  the  positive  field  of  the 
inner  grid  and  of  repelling  all  electrons 
going  to  the"  plate. 

We  have  a  high  current  inner  grid- 
filament  and  no  other  current,  (part  d  of 
Fig.  I).  The  potential  of  the  grid  being 
between  35  and  20  negative,  the  neutrali- 
zation  of  the   positive   field   of   Grid   GI 


Showing  the  method  of  using  the  double  grid  tube  in  the 
regenerative  circuit.  Note  especially  the  method  of  plac- 
ing the  low  voltage  "B"  battery  in  the  circuit. 


WHEN   the   nega- 
tive  potential 
on  the  grid  G  is  be- 
tween    20     and     10, 
more  electrons  go  to 
the  inner  grid  and  its 
current  increases  for 
the    same    reason    as 
above.      A   few   elec- 
trons reach  the  plate 
and     a     small     plate 
current    is    obtained 
(Fig    I,    f.)      With    a 
positive  potential  ap- 
plied to  the  grid,  the  control  grid  current 
appears,    less   electrons   reach   the   inner 
grid  as  more  and  more  are  attracted  by 
the  control  grid  and  the  plate.     Conse- 
quently, the  inner  grid  current  will  drop 
more  and  more  and  the  control  grid  and 
the  plate  currents  will  increase,  the  latter 
as  fast  as  the  inner  grid  current  decreases. 
The  above  theory  having  been  grasped, 
the   reader   will   understand   readily   the 
following  hook-up.      If  the  plate  circuit 
is  used  alone,  the  hook-up  is  very  alike  to 
a  three-electrode  tube. 

For  detection,  the  hook-up  of  Fig.  2 
is  to  be  recommended.  Detection  is  ob- 
tained with  the  grid  condenser 
and  grid  leak.  Regeneration  is 
obtained  as  with  an  ordinary  tube 
and  any  regenerative  hook-up 
may  be  equipped  with  a  double 
grid  tube  with  very  little  work. 
The  control  grid  must  be  at  a 
potential  of  about  two  volts 
positive,  as  regards  the  negative 
end  of  the  filament;  for  this 
reason  a  400-ohm  potentiometer 
is  to  be  used  as  shown,  the 
movable  arm  being  connected  to 
the  grid.  A  high  resistance  rheo- 
stat is  recommended  for  the 
tube  filament  circuit  (a  30-onm 
one  will  do  nicely)  as  accurate 
control  of  the  filament  tempera- 
ture will  help  in  getting  the  best 
results.  Detection  may  also  be 
obtained  without  any  grid  con- 
denser and  grid  leak  by  using  the 
great  curvature  of  the  plate  cur- 
(  Turn  to  page  60) 


20 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


How  to  Wind  a  LOW  LOSS  Coil 

that  Gets  DX 


Good  Low  Loss 

Coil  Easy  to  Make 

And  Yet  Itsa  Vital 

Factor  in  a  Well 

Built  Set 


Contrary  to  the  belief  of  many  radio  fans, 
a  low  loss  coil  is  very  easy  to  make.  A 
paper  template,  a  drill,  some  dowell  pins, 
or  long  steel  bolts,  and  an  ordinary  piece 
of  board  or  bakelite  (if  the  steel  bolts  are 
decided  upon),  are  the  only  paraphernalia 
required,  aside  from  the  wire  itself. 

The  photo  at  the  left  shows  the  manner 
of  laying  out  the  paper  template  on  the 
base.  The  lines  between  the  black  dots, 
that  represent  the  dowell  pins,  illustrate 
the  method  of  winding  the  wire. 


After  the  base  has  been  drilled,  insert 
the  dowell  pins  in  the  manner  shown  at  the 
right.  Be  sure  that  they  are  perfectly 
straight  and  start  to  wind  the  coil  as  shown 
in  the  first  photograph.  The  shape  of  the 
coil  will  be  determined  by  the  manner  in 
which  the  wire  is  ivound  in  and  out  of  the 
dowell  pins,  or  steel  bolts.  The  pins  should 
be  well  fastened  to  the  base,  so  as  to  prevent 
their  bending  in  at  the  top  and  thus  not 
giving  the  coil  a  uniform  appearance. 

However,  the  "over  two,  under  two"  style 
of  winding  is  generally  used.  This  means 
that  the  wire  goes  over  two  of  the  dowell 
pins,  and  under  the  two  dowell  pins  im- 
mediately following  the  first  two.  A  fin- 
ished coil  using  this  style  of  winding  is 
shown  at  the  lower  right.  The  coil  pictured 
contains  both  a  primary  and  secondary 
winding. 


""IkJilit-' 


c\  "*-  •' 

,.*i 

The  photograph  above  shows  the  winding 
of  the  coils,  using  No.  20  DCC  wire.  The 
winder  is  using  the  "over  two,  under  two" 
style  of  winding. 


After  the  coil  is  completely  wound,  remove  it  carefully,  by  the  simple  method  of 
loosening  the  dowell  pins  or  steel  bolls.  A  small  amount  of  collodian  or  glue  can  be 
used  to  hold  the  ends  together,  while  you  weave  a  string  or  thread  between  the  sides 
to  hold  it  together.     Be  careful  in  applying  the  collodian,  and  use  it  very  sparingly. 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour        21 


Event  Proves  that  Daytime  Reception  Has  Many 
Advantages,  But  They  Are  Offset  by  Distance 
Possible  at  Night;  Darkness  Stabilizes  Long  Waves 


EVER  since  the  discovery  of  radio 
communication,  many  inexplic- 
able sounds  and  noises  have 
been  found  to  cause  considerable  inter- 
ference to  the  clear  reception  of  distant 
signals,  and  especially  was  this  noticed 
during  the  hot  Summer  months.  Dur- 
ing the  colder  months,  when  the  nights 
were  clear  and  the  air  was  crisp  and 
snappy,  communication  was  established 
between  stations  several  thousands  of 
miles  apart  and  the  interfering  noises, 
while  still  apparent  to  some  degree, 
Were  so  decidedly  reduced  as  to  be 
practically    of    no    consequence. 

Just  why  the  hot  weather  reduced 
the  signal  strength  as  compared  to  the 
cold,  or  why  the  signals  would  gradually 
fade  away  at  almost  clock-like  regularity 
and  return  again  to  normal  strength, 
has  been  somewhat  of  a  mystery.  Vari- 
ous theories  have  been  advanced  for 
these  peculiarities,  but  none  of  them 
has  ever  been  actually  proven,  although 
experiments  have  shown  that  the  sun 
has  much  to  do  with  the  case. 

Variation   in   Signal   Strength 

ONE  thing,  however,  has  been  con- 
clusively proven;  that  is,  that 
night  reception  is  practically  ten  times 
as  good  as  daylight  reception.  Distant 
reception  of  the  broadcast  wave  is  not 
expected  during  the  daylight  hours, 
for  experience  has  shown  that  the  short 
waves  used  for  this  work  do  not  cover 
any  great  distance  during  the  day- 
light hours,  but  after  the  sun  has  dropped 
below  the  horizon,  conditions  are  entirely 
different. 

Just  why  these  conditions  apply 
has  been  explained  in  the  following 
way.  First,  it  is  believed  that  electro- 
magnetic waves  travel  through  a  layer 
of  atmosphere  next  to  the  earth's  surface. 


By  FRANK  D.  PEARNE 


This  layer  extends  from  the  earth  to 
a  mere  matter  of  thirty  or  forty  miles 
in  height,  and  above  this  the  atmosphere 
is  of  very  low  density  and  is  called  the 
heaviside  layer,  which  is  supposed  to 
be  a  film  of  highly  ionized  air.  This 
ionized  layer  of  air  has  a  tendency  to 
reflect    the    radio    wJave    in     about    the 


(Kadel  and  Herbert) 

How  the  recorder  makes  a  record  of 
radio  fading.  Few  fans  know  that  even 
local  stations  fade.  The  record  on  the 
strip  of  paper  shows  how  uneven  some 
distant  stations  are  received  in  New  York. 
If  the  reception  was  consistent,  a  perjectly 
straight  line  would  show. 


same  way  in  which  a  light  is  reflected 
from  a  mirror.  This,  in  combination 
with  the  rays  of  the  sun,  increases  the 
conductivity  and  the  radio  wave  re- 
bounds in  such  a  way  that  a  receiving 
station  located  at  a  distance  of  100 
or  more  miles  from  the  transmitting 
station  will  not  only  receive  the  direct 
wave,  but  also  the  wave  which  is  re- 
flected back  from  the  heaviside  layer. 
This  wave  is  alternating  in  its  nature, 
being  first  positive  and  then  negative, 
these  reversals  taking  place  a  million 
or  more  times  in  one  second.  If  the 
receiving  aerial  is  cut  by  both  the 
original  and  the  reflected  wave  at  the 
same  instant,  and  they  are  both  at  the 
same  polarity  at  the  same  instant, 
then  the  signal  will  be  quite  strong; 
but  if  one  wave  happens  to  be  at  maxi- 
mum and  of  a  positive  polarity,  when 
the  other  is  at  maximum  at  a  negative 
polarity,  then  the  result  of  the  two 
waves  will  be  zero  and  no  signal  will 
be  heard.  The  farther  the  two  waves 
vary  from  the  same  phase,  the  weaker 
the  signal  will  be,  and  the  nearer  they 
are  .  to  the  same  phase,  the  stronger 
it  will  be.  Here  then,  we  find  that  we 
have  not  only  the  absorption  of  the 
wave  energy  to  consider  when  it  travels 
a  great  distance,  but  also  the  effect  of 
the  reflected  wave.  This  theory  ex- 
plains to  some  extent  why  a  distant 
station  several  hundreds  of  miles  away 
from  the  transmitting  station  may 
hear  a  signal  which  is  not  heard  by  a 
receiver  which  is  not  so  far  away.  It  is 
easily  seen  that  the  height  of  the  heavi- 
side layer  will  determine  the  phase 
difference  between  the  two  waves  and 
consequently  the  signal  strength.  Now, 
because  the  height  of  this  layer  varies 
considerably  during  the  night  and  is 
practically    stationary    during    the    day, 


22         RADIO  AGE  for  March,  1925 
we    find   one   great   advantage    in    day- 


Eclipse   Offers    Opportunity 


The  Magazine  of  the  Hour 
side   of   this   zone    would   probably  not 


light    reception,    although    it    may    not  npnE  coming  of  the  eclipse  on  Janu-  receive   as    well, 

be  so  good  in  other  ways.  A    ary  24th  presented  the  opportunity          Nature     had     been     kind    enough    to 

of  a  life-time  to  prove  or  disprove  these  give  the  opportunity  and  man   was  not 

Cause   of   fading  theories.     In  certain  parts  of  the  United  slow    in    taking    advantage    of    it.      All 

IT     means    that    the    varying    of    the  States    a    total    eclipse     was    to    occur,  prominent    universities    prepared   for   it. 

height  of  this  heaviside  layer  will  vary  Here,    then,    we   should    have   the   ideal  Scientists    traveled     hundreds    of    miles 

the    phase    relation    of    the    two    waves,  condition   to   determine   whether   or   not  to  be  able  to  be  at  the  most  advantageous 

so  that  at  one  time  the  signal  may  be  the  blotting  out  of  the  sun's  rays  for  a  locations     to     record     the     results,     but 

strong    and    in    a    minute    or    two    may  short    time    would    affect    the    daylight  alas,   Dame   Nature  was  not  so  kind  to 

fade  away,  coming  back  to  full  strength  reception.     If  it  were  found  that  messages  some  of  them,   for  in.  some  of  the  best 

again  when  the  layer  again  reaches  the  could  be  transmitted  and  received  dur-  locations  for  making  observations  great 

proper    height    to    set    them    in    phase  ing    the    time    when    the    moon    cut    off  banks  of  clouds  prevented  many  of  the 

again.     This  causes  the  effect  of  fading  the   rays,   equally   as   well   as   when   the  most   interesting  features   of  the  eclipse 

signals,     which     is     seldom     noticed     in  sun  was  on  the  other  side  of  the  earth,  from    being    seen     by    those    who    had 
the  daytime  but  is  quite 


common  at  night.  On 
the  other  hand,  the  effect 
of  the  sun  on  daylight 
reception  is  supposed  to 
be  such  that  air  is  ionized 
to  some  extent,  thus  in- 
creasing its  conductivity, 
■which  would  naturally 
reduce  the  efficiency  of 
the  transmitted  wave. 

When  the  sun  is  on 
the  other  side  of  the 
earth,  its  ionizing  effects 
are  not  present  and  the 
efficiency  of  radio  trans- 
mission is  greatly  in- 
creased. The  line  of  sun- 
rise or  sunset  when  it 
comes  between  two  dis- 
tant stations  will  almost 
entirely  prevent  recep- 
tion. Another  advantage 
of  daylight  reception  is 
that  during  the  morning 
hours  very  little  static 
or  atmospheric  disturb- 
ance is  noticed.  This  is 
attributed  to  the  fact 
that  thunderstorms  sel- 
dom occur  in  the  morn- 
ing, or  at  least  do  not 
occur  as  often  as  they 
do  in  the  afternoon,  and 
then  too,  the  daylight 
transmission     of      these 


iKadel  &  Herbert) 

Here  is  a  view  of  the  recording  apparatus  used  to  test  the  effect  of  the 
eclipse  on  radio  reception.  Two  radio  receiving  sets  were  used;  one 
to  receive  waves  below  100  meters  and  the  other  for  the  longer  waves. 
Instruments  capable  of  showing  minute  fluctuations  of  fading,  etc.,  were 
coupled  to  the  sets.  The  tests  practically  proved  that  short  waves  lose 
strength  at  night  and  reach  maximum  efficiency  during  the  day. 


traveled  far  in  the  hope 
that  something  of  great 
importance  might  be 
accomplished.  However, 
this  did  not  happen  every- 
where and  some  interesting 
facts    were  recorded. 

Some  of  the  Results 

TY/I"  EMBERS  of  the 
-L»  J-  American  Radio  Re- 
lay League,  who  were 
scattered  around  in  the 
band  of  totality,  were  not 
able  to  get  much  definite 
information.  Engineers 
making  tests  in  New  York 
and  along  the  Atlantic 
seaboard  obtained  some 
facts  which  were  worth 
while.  Their  experiments 
proved  that  a  short  wave- 
length follows  the  sun 
and  also  that  static  inter- 
ference is  not  caused 
entirely  by  any  local  con- 
dition, for  the  reason 
that  it  was  affected  by 
general  conditions.  Long 
waves  which  were  very 
irregular  before  the  eclipse 
were  noticeably  regular 
during  the  time  that  the 
sun  was  totally  obscured. 
It  will  be  remembered 
that    the    eclipse    started 


atmospheric  disturbances  meets  with  the  then  something  worth  while  would  be  just  at  sunrise.  Short  waves  of  seventy- 
same  difficulty  experienced  by  the  radio  accomplished.  five  meters  that  could  not  be  heard 
wave  and  therefore  has  less  effect  than  Radio  engineers  and  scientists  from  before  sunrise  began  to  come  in 
it  would  have  at  night.  all  over  the  world  looked  forward  to  faintly  and  as  the  sun  appeared 
Experience  then  shows  us  the  differ-  that  day  as  one  which  would  go  down  Srew  stronger  and  stronger.  While 
ence  between  daylight  and  night  recep-  in  radio  history.  Great  preparations  the  short  waves  were  '"creased  the 
tion  to  sum  up  in  the  following  manner:  were  made  in  all  parts  of  the  country,  statIC  was  also  increased.  When  the 
First,  that  signals  travel  much  farther  some  selecting  that  position  where  a  sun  became  entirely  obscured,  the  short 
at  night  than  in  the  daytime  and  the  total  eclipse  would  occur  and  others  waves  were  entirely  blotted  out,  show- 
fading  of  signals,  when  one  is  fortunate  taking  up  positions  of  less  advantage.  lnS  exactly  the  same  conditions  as 
enough  to  pick  up  the  distant  signals  Many  of  the  large  broadcasting  stations  before  the  sun  rose.  As  the  moon 
in  the  daytime,  is  almost  unknown,  made  arrangements  to  come  on  the  slowly  passed  from  in  front  of  the  sun. 
This  gives  one  factor  in  favor  of  each.  a'r  before  and  during  the  period  of  the  short  waves  and  the  static  re- 
c  ,  c  ,  it  ,  .  totality  so  that  any  change  in  signal  aPPeared  and  gained  in  strength  as  the 
Second,  we  find  that  atmospheric  st  th  mi  ht  be  noted  Broad*ast  sun  appeared.'  Longer  waves  of  380 
disturbances  at  night  are  far  more  pro-  listeners  everywhere  were  asked  to  "meters  which  were  irregular  before  the 
nounced  than  during  the  day,  which  is 
another    factor    in    favor    of    each. 


nounced  than  during  the  day,  which  is     co.operate  and   report   immediately  any     eclipse   became   regular   as   the   sun   dis- 


changes    wnich    they    might    note.       In  appeared    behind    the    moon    and    when 

any    event,    the    great    increase    in    the  fact,  the  stage  was  set  so  that  at  some  the    sun     began     to    appear    again    the 

distance   covered   by   night   transmission  mt     at     ,east     someth;  mi  h       ^  wave    began    to    be    irregular    and    the 

more    than    offsets    the    advantages    of  learned   which    wouW    do    ^uch  8tQward  static    returned.      In    other    words,    the 

that    of    daylight    transmission.      If   the  ciearing  up  the  mystery  of  radio  recep-  long  waves  were  stabilized  by  darkness, 

theories  which   have  been   advanced  by  +;„„  „        _  .,    '  .  .  ,  ,   ■       ,  \. 

.,  .  c    .,        ,  non.  Dr     Goldsmith,    who    conducted    the 

the    greatest    engineers    ot    the    day    are  rr  j.u     *i_  j     -^       •  i  ^  j        -l   j    It.  _■-,.• 

.,  f        .     .  '  It   the  theories   were   sound,   it   might  tests,    described   the   conditions   as   gen- 

really  correct    then   it  is  very  apparent  be    eXpected    that    two    stations    which  erally    favorable,   being   about   half   way 

that  the  sun  has  a  great  deal  to  do  with  were  located  within  the  zone  of  totality  between    those    of    the    best    day    and 

the    matter,    but    as   before   stated,   this  could  transmit  and  receive   with   night-  those  of  the  worst  night.     In  these  tests 

has  never   been   actually  proven.  time  efficiency,  while  those  located  out-  a  "fading  recorder"  was  used. 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour  23 


Perfecting  the 

"BABY 
GRAND 


%\  As  Developed 
by 
Paul 
Green 


Recent 
Tests  by 
Radio  Age 
Readers  Improve 
This  Latest  Super 


7N  A  recent  article  on  the  "Baby 
Grand"  Super-heterodyne,  Paul 
Green  described  the  circuitinits  sev- 
eral modifications.  Radio,  like 
everything  else,  is  a  product  of  evo- 
lution. All  of  the  best  circuits  have 
undergone  numerous  changes  before 
reaching  their  final  stage  of  near  per- 
fection. Yes,  we  said  near  perfec- 
tion; anyone  would  be  foolish  to  call 
a  radio  set  perfect.  The  "Baby 
Grand"  appeals  to  all  who  have  seen 
and  heard  it  as  one  of  tlie  most  per- 
fect things  they  have  encountered  in 
radio  up  to  the  present  time. 


Front  view  of  the  "Baby  Grand"  Super-heterodyne, 
with  the  loop  antenna,  mounted  on  the  top  of  the  cabinet. 
This  shows  the  result  of  careful  design,  in  laying  out 
various  parts. 


IT  IS  two  months  now,  since  the  first 
of  this  series  of  articles  appeared 
describing  the  Baby  Grand.  The 
readers  of  RADIO  AGE  have  been  of 
considerable  assistance  in  helping  to 
develop  this  circuit.  It  has  now  reached 
a  stage  of  perfection  which  is  little  short 
of  astonishing. 

There  was  a  time,  and  not  so  very 
long  ago  either,  when  eight  tubes  were 
the  least  that  could  be  used  on  a  super- 
heterodyne and  still  bring  in  so-called 
super-heterodyne  results.  At  that,  the 
eighth  tube  was  usually  ineffective.  By 
eliminating  the  losses  that  have  occurred 
in  previous  circuits,  particularly  as 
regards  the  input  and  output  coils,  it  is 


now  possible  to  condense  the  circuit  to 
six  tubes,  and  yet  secure  approximate 
eight  tube  volume  and  distance. 

We  can  all  recall  the  time  when  air 
core  transformers  were  thought  to  be 
absolutely  the  only  transformers  that 
could  be  used  in  the  super-heterodyne 
circuit.  We  were  taught  that  iron  core 
transformers  were  broad,  and  that  a 
greater  degree  of  amplification  could 
be  secured  by  using  air-core  trans- 
formers. That  these'  theories  have  all 
been  proven  merely  theories  goes  without 
saying.  To  build  an  entire  Super- 
heterodyne using  iron  core  transformers 
throughout  would  have  sounded  like 
the  height  of  idiocy  to  our  super-hetero- 


8-Tube 

Volume  and 
Distance  Easy 
With  This   Six- 
Tube  Wonder  Set 


dyne  forefathers;  however,  that  is 
exactly  what  we  do  in  the  Baby 
Grand  in  its  present  form.  In 
the  previous  installment,  we  were 
still  using  the  air  core  filter.  Ex- 
periments revealed  that  we  were 
encountering  a  loss  in  this  air  core 
transformer  which  was  keeping 
the  volume  down.  Substituting 
an  iron  core  input  coil  of  the  same 
make  as  the  intermediates  has 
solved  the  problem,  and  not  only 
that,  but  it  is  not  necessary  to  tune 
this  transformer.  A  graph  of  the 
three  transformers  working  to- 
gether reveals  the  fact  that  the 
peak  is  very  high  and  as  sharp  as  it  rea- 
sonably can  be  expected  to  be  and  still 
include  the  effective  band  of  frequencies. 


Condenser  Layout 

THE  panel  dimensions  for  previous 
layouts  were  7x18'.  The  present 
design  calls  for  a  panel  of  8xl5>£". 
It  will  be  noted  that  a  sub-base  is  em- 
ployed and  that  it  rests  on  top  of  two 
end  brackets.  This  permits  of  placing 
the  transformers  on  the  under  side  of 
the  sub-base  with  the  tubes  and  sockets 
on  the  upper  side.  All  of  the  leads  be- 
tween tubes  and  transformers  are  ex- 
tremely short.     The  base  panel  is  4x15 


24 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


77ie  above  photograph  shows  the  upper 
to  how  the  tube  sockets  should  be  mounted., 
variable  condensers. 

and  provides  ample  space  for  all  apparatus. 

The  loop  is  mounted  directly  on  top 
of  the  set,  so  that  the  loop  leads  are  only 
a  few  inches  in  length.  The  loop  is  of 
the  bank  wound  type  and  is  19x19 
inches.  As  the  overall  depth  of  the  set, 
exclusive  of  binding  posts  is  8  1-2,  it  can 
readily  be  seen  what  a  wonderful  layout 
this  is  from  the  standpoint  of  port- 
ability. 

As  in  the  previous  circuit,  the  first 
detector  tube  bias  battery  is  omitted 
and  in  its  place  a  grid  leak  is  used.  It 
is  found  that  this  has  a  tendency  to 
keep  the  circuit  very  quiet,  while  at  the 
same  time  eliminating  the  "C"  battery. 
It  will  be  noted  that  very  good  judgment 
has  been  exercised  in  the  selection  of 
variable  condensers,  dials,  rheostats, 
loop,  transformers  and,  in  fact  every- 
thing which  in  any  way  can  affect  the 
operation  of  the  set. 

The  base  of  the  loop  is  provided  with 
a  5-16"  brass  pin  of  1  inch  in  length. 
The  top  of  the  box  or  cabinet  has  a  hole 
of  slightly  larger  dimensions  to  receive 
this  pin.  The  loop  terminals  engage  in 
imp  jacks  which  should  be  mounted 
in  a  piece  of  hard  rubber  or  bakelite 
on  the  top  of  the  cabinet  and  kept  from 
touching  the  wood  of  the  cabinet.  The 
leads  of  these  jacks  run  directly  to  their 
respective    connections    in    the    circuit. 

Under-Side  of  Sub-Base 

THE  intermediate  transformers^  being 
of  the  iron  core  type  and  shielded, 
can  be  placed  very  close  together  without 
any  symptoms  of  inter-stage  reaction. 
If  it  were  not  for  this  fact,  it  is  doubtful 
whether  it  would  be  possible  to  build 
a  practical  6-tube  super-heterodyne. 
The  audio  transformer  is  of  the  same 
make  as  the  intermediates  and  occupies 
very  little  space.  The  two  by-pass 
condensers  included  within  the  oscillator 
circuit  are  found  just  back  of  the  input 
transformer  and  are  connected  in  com- 


part  of  the  "Super."       This  will  give  one  an  idea  as 
so  as  not  to  interfere  with  the  oscillation  coupler  or 


mon  to  the  negative  "A"  return,  through 
the  filament  rheostat. 

The  other  side  of  each  of  these  con- 
densers is  connected  to  the  positive 
"A"  battery  return  and  the  plus  "B" 
battery  return  respectively.  Not  using 
a  bias  battery  permits  of  placing  the 
rotor  of  the  oscillator  in  the  circuit  so 
that  the  circuit  leads  from  positive  "A" 
return  through  the  rotor  to  the  middle 
tap  of  loop,  through  loop  to  stator  side 


of  the  loop  condenser,  to  grid 
leak,  through  grid  leak  to  grid 
of  first  detector  tube. 

Heretofore,  when  using  bias 
"C"  battery,  it  was  placed 
with  its  positive  side  con- 
nected to  the  negative  "A" 
return  in  common  with  one 
side  of  each  of  the  by-pass  con- 
densers. The  rotor  of  the  os- 
cillator was  then  placed  in  the 
position  now  occupied  by  the 
grid  leak  and  grid  condenser. 
Further  examination  will  re- 
veal that  the  cases  of  the  two 
intermediates  are  grounded  in 
common,  on  the  plus  "A"  bat- 
tery lead.  The  by-pass  con- 
denser across  the  positive  "B" 
and  detector  "B"  is  fastened 
to  the  side  of  the  supporting 
bracket.  The  transformers 
are  mounted  on  top  of  a  nar- 
row piece  of  one-quarter  of 
an  inch  bakelite,  so  that  the 
transformer  as  a  whole  stands 
one-quarter  of  an  inch  away 
from  the  underside  of  the 
sub-base. 

This  leaves  plenty  of  room 
for  running  the  longitudinal  wiring 
and  keeps  it  well  out  of  the  way.  The  by- 
pass condenser  across  the  primary  of 
the  audio  transformer  is  usually  found 
to  work  best  if  it  is  about  .004  capacity, 
although  this  capacity  can  only  be  de- 
termined by  experimenting,  as  char- 
acteristics of  individual  sets  will  vary 
somewhat.  However,  it  is  extremely 
important  that  this  capacity  be  right, 
otherwise,     the    best      (Turn  to  page  66) 


A  view  of  the  "Baby  Grand"  Super-heterodyne  from  the  rear.  Note  especially  the 
method  of  mounting  of  the  long  wave  transformers  directly  under  the  radio  frequency 
tubes.      This  method  provides  for  exceptionally  short  connections. 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour        25 


Experimenting  with 
Short  Waves 

By  C.  HAROLD  DILLON 


THE  average  radio  fan  of  today 
"builds  his  own."  Truly,  he  ap- 
parently is  never  satisfied  and 
always  has  an  idea  that  the  manufactured 
set  is  better  than  his  own  product.  And 
what  is  a  fine  circuit  this  week  is,  ap- 
parently, cast  into  oblivion  the  next. 

This  is  as  it  should  be.  For,  not  only 
is  he  satisfying  himself  regarding  the 
value  of  the  various  circuits,  but  he  is 
doing  considerable  experimenting  for 
the  radio  industry  in  general.  It  is  in 
this  manner  that  new  circuits  are  de- 
veloped and  perfected. 

How  many  times  have  you  noticed 
that  a  circuit  will  be  heralded  as  the 
best  and  most  desirable,  only  to  find 
that  after  a  short  period,  improvements 
will  be  announced?  Check  up  on  these 
improvements  and  what  are  they?  A 
fixed  condenser  added  here,  a  reversed 
connection  there,  and  the  perfected 
circuit  will  be  many  times  better  than 
the  original.  These  things  are  not  found 
by  formula,  but  rather  by  experiment. 
Hence  we  look  on  the  radio  set-builder 
as   an    experimenter. 

Take,  for  example,  one  of  the  lunda- 
mental  circuits  of  radio  reception,  the 
"old    reliable"    three-circuit    receiver. 

New  Tuner  Tested 

I"  TNTIL  a  few  short  months  ago,  what 
^  was  looked  upon  as  ideal  equipment 
consisted  of  a  vario-coupler  and  a  pair 
of  variometers.  These  are  in  them- 
selves admirable  pieces  of  apparatus. 
But  how  much  more  efficient  are  the 
small   skeleton-wound   three-circuit   tun- 


At  the  left  is  a 

back  view  of  Mr. 
Dillion  s shortwave 
receiver.  The  sim- 
plicity of  the  wir- 
ing and  the  efficient 
spacing  of  the  ap- 
paratus is  evident. 


ers,     all     mounted    on     one         j 
small    bakelite   frame!     Not 
only  are  they   more  efficient         I 
electrically,     but     they     are 
much   more  convenient    me- 
chanically. 

No  formula  was  directly  jj 
responsible  for  their  devel-  VKmmmfi. 
opment.  It  was  accom- 
plished by  experiment.  So  we  must  con- 
sider the  man  who  builds  his  own,  not 
as  a  "dabbler"  but  as  an  experimenter 
who  very  frequently  contributes  some- 
thing to  the  science  for  our  own  common 
good.     So  much  for  the  experimenter. 

Almost  all  of  us  have  by  this  time 
advanced  through  the  maze  of  crystal, 
regenerative,  neutrodyne  and  reflex 
stages,  and  are  looking  around  for  new 
and  more  fertile  fields  in  which  to  try 
our  hand.  Such  being  the  case,  it  is 
time  we  considered  the  most  recent  addi- 
tion to  our  already  broad  field — short 
wave  reception. 

Before  we  go  any  farther  into  the  sub- 
ject, it  might  be  well  to  explain  that  by 
short  waves  we  mean  those  waves  whose 
bands  are  below  those  covered  by 
the    amateurs    and    broadcasters. 

For  the  past  two  and  one-half  years 
much  has  been  said  and  written  con- 
cerning short  waves,  and  most  of  these 
explanations  have  called  for  a  good  deal 
of  special  apparatus.  Most  of  us,  after 
reading  a  few  such  reports,  surrendered 
the  subject  to  the  scientist,  and  went 
back  to  problems  nearer  home. 

Many  of  the  larger  stations  of  this 
country  such  as  WGY,  KFKX,  KDKA, 


The  Latest  Thing 
in  Radio 

The  men  who  know  what's  what 
in  the  world  of  radio  are  predict- 
ing that  the  broadcasting  of  the 
future  will  be  done  by  means  of 
short  waves,  which  are  now  being 
used  by  only  a  few  broadcasters 
suchas  KDKA,  WGY.and  KFKX. 
In  the  accompanying  article 
RADIO  AGE  presents  to  its  read- 
ers for  the  first  time  a  construc- 
tion article  for  those  fans  who  wish 
to  build  a  simple  short  wave  re- 
ceiver. All  the  parts  are  standard 
and  there  are  no  "tricks."  It  will 
be  great  sport  indeed  to  hear  broad- 
cast programs  on  84  meters  or 
thereabouts.  We  shall  be  pleased 
to  hear  from  readers  regarding 
clarity  of  reception,  and  other  re- 
sults obtained  with  this  receiver. 


etc.,  are  using  short  waves  with  regular- 
ity, and  it  only  remains  for  the  fan  to 
construct  a  set  capable  of  tuning  low 
enough  that  will  enable  him  to  receive 
these  short  wave  signals  and  put  him  in 
the  front  rank  of  radio  experimentation. 
The  set  to  be  described  will  consist  of 
a  detector  and  two  stage  audio  frequency 
amplifier.  It  is  very  easy  to  construct, 
and  the  wiring  has  been  simplified  by 
using  soft  wire  in  place  of  the  usual  stiff 
bus  bar  style  of  connection.  The  tuner 
is  particularly  efficient,  being  quite  small 
and  carrying  no  dead  end  losses.  It 
covers  the  wave  band  on  which  it  is  to 
be  used,  fifty  to  one  hundred  and  ten 
meters,  very  nicely.  The  primary  is 
adjustable  and  untuned,  thus  permitting 
it  tb  be  adjusted  to  meet  your  own  par- 
ticular requirements.  Selectivity  can 
be  secured  by  increasing  the  coupling 
between  primary  and  secondary,  a  small 
bracket  being  supplied  for  that  purpose. 
The  tickler  or  feed-back  coil  has  a  180- 
degree  variation  and  is  wound  with  the 
lowest  essential  number  of  turns  to  se- 
cure perfect  action  of  this  control.  It  is 
wound  in  such  a  manner  as  to  insure  low 
capacity  effect  against  the  secondary. 
The    secondary    coil    itself    is    low    loss, 


26        RADIO  AGE  for  March,  1925 


Front  panel  view  of  the  completed  short  wave  receiver.     The  dial  to  the  left  is  the  wave- 
length control,  while  the  one  on  the  right  controls  the  tickler  or  regeneration  coil. 


space  wound.  This  means  that  the  turns 
of  wire  do  not  touch  one  another,  but 
are  separated  by  a  slight  "air  gap" 
about  as  wide  as  the  wire  itself. 

Now  Used  for  DX 
Tj^OR  some  time  it  has  been  known 
-*-  -  that  short  waves  could  be  used  for 
transmitting  purposes.  However,  until 
quite  recently  they  were  not  considered 
satisfactory  for  long  distance  work. 

Heinrich  Hertz,  the  German  physicist, 
used  them  in  his  experiments.  By  their 
use  he  was  able,  with  the  aid  of  apparatus 
he  had  perfected,  to  be  the  first  to 
measure  a  radio  wave.  While  he  was 
experimenting  with  short  wave  trans- 
mission, he  devised  what  is  known  as 
the  "Hertzian  oscillator"  which  is  used 
today  in  connection  with  short  wave 
experiments. 

After  Hertz's  experiments,  short  waves 
were  forgotten,  as  they  were  thought 
to  be  of  no  practical  use.  During  the 
war  they  were  used  to  a  small  extent, 
and  quite  recently  Marconi  did  phenom- 
enal work  in  transmitting  signals  from 
England  to  Australia,  on  a  100  meter 
wavelength,  with  remarkably  low  power. 


What  are  the  advantages  of  short  wave 
transmission?  The  one  big  advantage 
is  the  high  radiation  efficiency  gained. 
For  the  same  input  power,  stronger  waves 
will  be  sent  out  from  the  antenna,  the 
shorter  the  wavelength  used.  Another 
advantage  is  the  elimination  of  static 
to  a  large  extent.  This  latter  advantage 
can  be  accounted  for  in  a  great  measure 
by  the  comparatively  small  antenna 
used   at   the   receiving   end. 

So  much  for  explanations;  now  for  the 
construction   details.      To   build   the   set 
you  will  need  the  following  parts: 
BILL   OF   MATERIALS 

1   Short   wave  tuner, 

1    Condenser,   variable,   to   match 
tuner, 

1  Panel  T'xW'x'X", 

1  Sub-panel  12"x3}i"xJ4"j 

1  Set    of    brackets    for    mounting 
sub    panel, 

2  Audio    frequency    transformers, 
1  Grid  leak,  1  to  2  megohms, 

1    Grid   condenser    .00025    MFD, 
1  Single  circuit  jack, 
1  Double  circuit  jack, 
1  Filament  switch,'' 


The  Magazine  of  the  Hour 

3  Vacuum  tube  sockets, 

1  Rheostat,  resistance  to  be  de- 
termined by  the  tube  used  as  a  de- 
tector. 

2  Fixed  resistance  cartridges,  for 
controlling  filament  heat  on  the 
amplifier    tubes. 

7  Binding  posts, 

2  Dials, 

—  Wire,  screws,  etc. 

For  receiving  short  wave,  high  power 
transmission,  as  this  set  is  designed  to 
pick  up,  you  should  employ  an  antenna 
whose  length  should  not  exceed  eighty 
feet  of  wire  from  the  farthest  point  to 
the  point  connected  to  the  set.  This  is 
in  accordance  with  the  principle  that 
short  antennas  give  greater  selectivity 
and  less  interference  from  static.  Keep 
the  antenna  as  far  as  possible  from  metal 
roofs,  gutters,  down  spouts  or  wire  lines. 

A  high  capacity  antenna  may  result 
in  raising  the  wavelength  of  the  antenna 
circuit  to  a  value  within  the  broadcast 
range,  thus  causing  interference  from 
local  or  nearby  stations  of  low  wave- 
length, regardless  of  the  position  of  the 
adjustable  primary.  This  may  be  easily 
remedied  by  placing  a  fixed  condenser 
in  series  with  the  antenna.  The  con- 
denser should  have  a  capacity  of  between 
100  and  500  MMF. 

You  should  be  sure  of  a  good  ground 
connection.  The  usual  water  pipe  in- 
stallation has  proven  very  satisfactory. 

As  the  circuit  itself  is  a  tried  and 
proven  one,  I  will  not  go  into  construction 
details  regarding  it.  A  few  hints  concer- 
ing  the  wiring  will  suffice.  Avoid  all 
angular  bends,  using  a  wire  about  the 
same  size  as  standard  bus,  but  more  flex- 
ible. 

Upon  completion  of  the  set,  the  ad- 
vanced experimenter  may  plunge  himself 
into  this,  the  newest  field  of  radio  re- 
search. And  let  him  remember,  that  the 
engineers  of  the  industry  are  all  predicting 
that  the  next  few  years  will  find  all  broad- 
casting done  on  short  waves. 


tzz'A  So/rs. 


\J?'//oM 


Wiring  diagram  of  the  three-circuit  short  wave  receiver,  described  in  the  accompanying  article.     The  dotted  lines  at  the  left  hand  side 
of  the  diagram  show  how  the  grid  return  is  placed  if  a  hard  tube  is  used  as  a  detector. 


RADIO  AGE  for  March,  1925 

Where 

is  Radio 

Leading 

Us? 

By  EDMUND  H. 
EI  TEL 

YW/ILL  Radio  Change 
W  Our  Ideas  of  Life 
and  our  Very  Philos- 
ophy? Possibilities  and 
Fundamentals  of  "Rad- 
iant Energy"  Explained 
for  The  Beginner  About 
to  Study  Ethereal  Secrets; 
Easy  Hookup  Shown. 


The  Magazine  of  the  Hour        27 


WHAT  is  radio  going  to  do  to  us? 
I  do  not  mean,  How  will  it  change 
our  lives  by  introducing  new  plea- 
sures and  new  conveniences;  it  will  do 
much  more  than  that. 

A  tremendous  question  to  consider  is, 
will  it  not  in  the  long  run  change  our 
very  thinking — will  it  reform  our  way  of 
looking  at  life;  in  other  words,  our  philo- 
sophy? 

Before  radio  is  done  with  us,  it  may 
cause  a  revolution  in  thought  as  radical 
perhaps  as  that  which  occurred  when 
Darwin  presented  his  theory  of  evolution. 

Knowledge  is  "Evolutionary" 
"T\ARWIN  stated  all  life  evolves  from 
-■-,  simpler  forms  through  a  process  of 
the  "survival  of  the  fittest."  After  his 
pronouncements,  we  soon  had  a  new  way 
of  thinking — a  new  way  of  looking  at  life. 
Systematic  knowledge  has  been  rear- 
ranged since  Darwin  according  to  the 
point  of  view  of  evolution.  Biology  and 
zoology,  for  example,  have  been  reclas- 
sified according  to  evolutionary  progres- 
sion. We  study  history  as  evolution. 
We  have  the  evolution  of  art.  We  even 
have  evolutionary  classifications  of  such 
diversified  things  as  chemistry,  philo- 
sophy and  religion. 

Is  it  possible  that  radio  may  bring  such 
a  profoundly  new  and  revolutionary  con- 
ception of  life?  Will  radio,  and  what  it 
essentially  signifies,  revise  our  thinking? 

It  is  not  at  all  improbable  that  radio 
may  bring  about  that  very  thing.  We 
may  be  on  the  threshold  of  new  ideas  of 
life.  To  begin  with,  radio  is  making 
millions,  young  and  old,  think  in  a  new 
way.  It  is  a  tremendous  educational 
force  for  science.  As  it  dawns  on  these 
inquiring   minds   what   radio,    or   radiant 


Whither  are  we  going?  What  mysteries  will  the 
radio  of  the  'future  unfold?  Oniy  the  figurative 
*'Lady  Quanta"  picturized  above  can  tell. 


energy,  really  is,  and  what  it  means,  the 
world  will  look  different  to  some  people. 

Exactly  what  radio  is  alone  is  a  signifi- 
cant question.  Have  you  not  often  put 
that  problem  to  yourself  as  a  beginner? 
When  you  get  that  question  adequately 
answered,  you  will  have  a  different  set  of 
values  of  life  than  you  ever  had  before. 

What,  then,  is  radio?  What  is  this 
force  which  flies  over  thousands  of  miles 
at  a  speed  of  186,000  miles  per  second  and 
passes  through  your  body  and  mine  all 
unknown  to  us;  even  through  brick  and 
stone,  unimpeded?  The  scientists  tell  us 
that  it  is  akin  to  the  gamma  rays  of 
radium,  to  X-rays,  to  the  actinic  rays  of 
the  sun;  to  light  and  to  heat;  and  they 
call  it  "radiant  energy." 

Radio  A  Ray 

"CURST  of  all,  Einstein,  Planck,  Bohr, 
*-  Milliken,  Michelson  and  other  pains- 
taking scientists  have  in  unlocking  the 
deepest  secrets  of  nature  proved  "that 
radio  is  not  a  wave  as  popularly  sup- 
posed. It  is  a  ray  consisting  of  well-nigh 
infinitesimal  particles. 

To  make  you  comprehend  how  amaz- 
ingly small  these  particles  are,  I  must  tell 
you  about  these  mslecules,  atoms  and 
electrons.  You  know  that  when  matter 
is  divided  and  subdivided  further  and 
further  that  you  finally  reach  a  particle 
which  can  no  longer  be  divided  without 
changing  its  nature.  This  is  the  mole- 
cule. 

For  example,  divide  a  molecule  of 
water  and  you  split  it  into  an  atom  of 
oxygen  and  two  atoms  of  hydrogen, 
these  atoms  being  gases. 

Atoms  are  most  incomprehensibly 
small.  They  have  been  measured,  and 
the  atom  of  helium,  for  example,  is  one- 


The  unim- 
posing  micro- 
phone  will 
play  an  im- 
portant role 
in  the  politi- 
cal and  edu- 
cational life 
of  the  future, 
this  author 
believes. 


fifty-millionth  of  a  centimeter  in  dia- 
meter. This  means  that  if  a  centimeter 
were  stretched  out  until  it  became  as 
long  as  the  diameter  of  the  earth  itself 
and  used  to  measure  the  helium  atom, 
the  diameter  of  the  latter  would  be  but 
9}4.  inches. 

But  a  centimeter  is  a  centimeter,  which 
means  it  is  approximately  two-fifths  of 
an  inch.  So  the  atom  is  small  indeed. 
And  yet,  small  as  it  is,  the  atom  is  a  vast 
system  in  itself,  resembling  the  solar 
system  more  than  anything  else.  For 
the  atom  has  a  nucleus,  or  "sun"  as  its 
center  and  around  this  from  one  to  about 
ninety  "planetary"  electrons  revolve. 

Professor  Milliken  says  that  Professor 
Wilson  has  with  a  series  of  ingenious 
photographs  indicative  of  electronic 
paths,  given  us  "the  most  convincing 
evidence  that  the  atom  is  a  sort  of  minia- 
ture stellar  system  with  constituents 
which  are  unquestionably  just  as  minute. 
with  respect  to  the  total  volume  occupied 
by  the  atom  as  are  the  sun  and  planets  and 
other  constituents  of  the  solar  system 
with  respect  to  the  whole  volume  en- 
closed within  the  confines  of  the  sys- 
tem." 

But  minute  as  the  atom  is,  and  in- 
finitely more  minute  its  constituent  elec- 
trons, there  is  something  still  "minuter." 
That  is  radio  or  "radiant  energy." 
Electrons    have    the    ability    to    migrate 


28         RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


along  an  electrical  conductor — a  wire  for 
example — and  such  a  current  of  electrons 
is  what  constitutes  the  current  of  elec- 
tricity. 

Let  us  alternate  this  current  in  a  trans- 
mitting antenna.  This  means  we  will 
send  the  electrons  surging  first  in  one 
direction  along  the  wire  and  then  in  the 
reverse  direction.  Each  time  we  reverse 
the  current  of  rapidly  surging  electrons, 
particles  still  smaller  than  the  electron  or 
"electron  dust"  are  jerked  loose  and  sent 
flying  in  all  directions  in  straight  lines. 
This  "dust"  consists  of  minute  "bags  of 
energy"  designated  by  Professor  Max 
Planck  as  "quanta." 

"Quanta"  Does  It 
TT  is  this  infinitesimal  "quanta"  which 
-^-carries  the  radio  message  at  the  speed  of 
186,000  miles  per  second  from  the  trans- 
mitting antenna  to  the  receiving  antenna, 
which  may  be  a  thousand  miles  away. 

This  brings  us  tp  the  significance  of 
radio  or  "radiant"  energy."  It  is  that 
which  we  know  as  "matter"  or  the 
material  world,  that  is  pot  so  solid  as  we 
had  supposed.  "Solid"  matter  is  ex- 
tremely thin  and  nebulous.  In  fact,  it 
is  no  denser  than  the  solar  system  with 
its  far-flung  planets.  Matter  is  only 
made  apparently  dense  through  the 
motion  of  its  constituent  particles.  A 
scientist  has  shown  this  with  a  striking 
example.  He  has  calculated  that  all  the 
battleships  in  the  world,  if  the  motion  of 
their  electrons  were  stopped  and  every 
particle  were  crowded  tightly  together, 
would  occupy  but  one  cubic  inch. 

What,  then,  is  the  human  being?  If 
even  steel  is  so  thin,  that  if  iron  is,  after 
all,  nebulous  or  like  air,  what  a  poor  thin 
substance  is  man!  We  are  like  ghosts 
indeed,  having  virtually  no  real  substance 
at  all — only  apparent  substance.  We 
may  indeed  be  spirtual  manifestations; 
and  although  this  term  would  not  mean 
anything  to  the  scientist,  we  may  specu- 
latively press  him  with  it  and  ask  him  to 
explain  what  the  "quanta"  consists  of  and 
whether  this  and  mind  may  not  be  the  same 
or  composed  of  at  least  one  fundamental 
substance  underlying  everything. 

Neither  can  the  scientist  answer   yet 
what  consciousness  is,   or  what  thought 
consists      of,      or      whether 
thought    may    not  be  trans- 
ferred like  radio.   Sir  Oliver 
Lodge  believes  it  can  be. 

Furthermore,  all  that  we 
see  and  experience  is  but  a 
small  fraction  of  reality. 
Our  eyes  are  "tuned"  to.  re- 
ceive light  rays  only.  Now 
radio  rays  are  the  same  thing, 
except  they  are  slower  in 
"frequency."  If  our  eyes 
were  properly  tuned,  we 
might  see  radio  rays  and  the 
world  would  appear  vastly 
different.  Or,  if  our  eyes 
were  tuned  differently  still, 
we  might  plainly  see  heat 
rays,  or  the  ultra-violet  rays 
of  the  sun,  or  X-rays.  Or 
about  a  radio  coil  we  might 
see  the  magnetic  rays  or 
"fields  of  force,"  whirling  and 
boiling.  All  this  is  just  as 
real  as  anything  we   do   see. 


How  differently  is  the  man  of  the 
future  going  to  conceive  of  the  reality  of 
the  world,  of  life?  Hasn't  the  imma- 
terial and  the  invisible  grown  in  great 
significance  because  of  radio?  Have  we 
not  become  dimly  conscious  of  the  vast- 


Showing  how  an  electron  composed  of 
several  atoms  throws  off  the  "quanta," 
which  carries  the  radio  message  at  a  speed 
of  186,000  miles  a  second  from  the  trans- 
mitting aerial  to  your  receiving  set. 

ness  of  the  unknown  world  .toward  which 
scientists  are  headed  like  new  Colum- 
buses? 

Not  only  is  the  solidity  of  this  material 
world  facing  to  the  new  sight  of  science, 
but  mind  is  ascending  by  aid  of  radio  to 
new  peaks  of  power  and  dignity.  A  man, 
the  President  of  the  United  States,  for 
example,  may  speak  today  and  his  mes- 
sage can  be  conveyed  to  the  ears  of  every- 
one of  the  110  million  souls  in  America, 
if  sufficient  receiving  sets  were  provided. 
Similarly  it  would  be  possible  as  soon  as 
sufficient  sets  were  on  hand,  for  one  man 
to  address  every  being  on  the  planet. 
Some  great  man  of  the  future;  some 
Clemenceau,  Wilson  or  Lloyd  George — 
some  modern  St.  Francis  or  Luther,  some 
new  Caruso  or  Beethoven,  some  future 
Einstein  or  Pasteur,  on  some  great  oc- 
casion might  address  virtually  all  man- 
kind from  pole  to  equator,  from  metro- 
polis to  jungle. 


V 


jm 


■W- 


So-TorvsS. 


ZT- 


.oooS  k    —  .«■/■ 


A       ~B  + 


The  simplest  form  of  a  radio  receiving  set  is  shown  above.  It  is 
of  the  type  that  is  commonly  known  as  a  single  circuit  receiver 
and    is    excellent  for    a    beginner's  experiments. 


While  such  a  thing  would  be  spec- 
tacular, it  would  have  a  deep  significance, 
too.  It  would  signify  that  just  as  dis- 
tance has  been  annihilated,  so  matter  has 
been  virtually  conquered  also  by  mind. 
One  hundred  ton  engines  and  heavy 
trains  are  no  longer  needed  to  complete 
communication.  The  spirit  of  men  has 
become  the  master  of  all  this.  That 
spirit  has  come  into  dominance  and  it 
follows  that  mind  and  spirit  will  take  on 
a  new  importance,  a  higher  valuation  in 
our  regard  for  life. 

And  this  will  be  all  the  more  true  when 
radio  makes  its  next  and  imminent  con- 
tribution, which  will  be  vision  at  a  dis- 
tance. 

For  the  benefit  of  the  "green"  beginner 
in  radio,  we  are  publishing  herewith  an 
unusually  simple  hookup  that  will  ex- 
plain itself  as  it  is  put  together  and 
operated.  It  is  the  construction  of  such 
simple  sets  as  this  one  that  will  lift  the 
veil  surrounding  radio  for  the  average 
reader. 

The  circuit  I  am  about  to  describe  to 
you  is  the  simplest  of  all  radio  cir- 
cuits. It  consists  of  a  simple  coil  of 
wire,  fifty  or  seventy  turns,  wound  on  a 
cardboard  or  bakelite  tube,  three  inches 
in  diameter. 

A  honey-comb  coil  can  be  used  in 
place  of  the  homemade  coil. 

Procure  from  your  radio  dealer  a  vari- 
able condenser,  having  a  capacity  of  .0005 
mfd.  (microfarads),  a  grid  leak  having  a 
resistance  of  about  two  megohms,  a  grid 
condenser  with  a  capacity  of  .00025  mfd., 
a  rheostat  having  a  resistance  for  the 
kind  of  tube  you  will  use  as  your  detec- 
tor, a  vacuum  tube  socket  to  fit  the  tube 
you  have  on  hand  or  prepared  to  pur- 
chase, and  a  small  fixed  condenser  for 
the  head-phones,  having  .001  mfd.  as 
its  capacity. 

Supposing  that  you  have  already  in- 
stalled your  antenna,  which  should  be  a 
single  wire  about  125  feet  long  from  the 
farthest  end  to  the  end  that  is  connected 
to  the  set  proper. 

The  next  thing  to  do  will  be  to  connect 

one  end  of  the  coil  to  one  terminal  of  the 

grid    leak.     The    other    terminal    of   the 

grid    leak   is   connected    directly   to   the 

grid    connection    on    the 

vacuum    tube    socket. 

The  other  terminal  of  the 
coil  is  connected  to  the  sta- 
tionary plates  of  the  variable 
condenser,  while  the  movable 
plates  are  connected  to  the 
ground  circuit.  By  consult- 
ing the  wiring  diagram,  you 
can  readily  determine  just 
how  the  balance  of  the  set 
is  wired. 

The  positive  side  of  the 
battery  used  to  heat  the 
filament  is  connected  to  the 
negative  side  of  the  battery 
that  supplies  the  plate  cur- 
rent, or  "B  '  battery.  A 
wire  from  the  negative  side 
of  the  "A"  battery  is  con- 
nected to  the  rheostat,  while 
the  positive  side  goes 
directly  to  one  of  the  fila- 
ment prongs  of  the  tube 
socket. 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour        29 


The  Sleuths  of  Honeymoon  Camp 


How  Three  Couples 
of  Newlyweds  Set  a 
"Radio  Trap"  for  a 
Couple   of  Burglars 

By 

FRANK 

HONEYWELL 


IT  LAST!  The  tandem  trio  of 
L\  honey-moon  couples  were  in 
■J-  ■*-  "honeymoon  camp."  Their 
planning  for  this  event  had  not 
been  so  long,  but  it  had  seemed 
long.  They  had  planned  intensively, 
and  when  folks  do  things  with  this  big 
word,  time  is  measured  with  instru- 
ments of  magnitude.  That  is  where 
we  get  the  expression  "big  time." 
All  these  three  couples  had  been 
married  in  tandem  succession  in  one 
month,  and  weeks  before  the  first  of 
their  weddings  they  began  to  plan  their 
honeymoon  together.  Several  confer- 
ences were  held,  and  the  whole  gamut  of 
mid-year  recreation  was  discussed.  In 
imagination  they  pictured  themselves 
going  all  the  way  from  the  Adirondacks 
to  the  Pacific  coast  and  from  Niagara 
Falls  to  the  woods  and  lakes  of  northern 
Wisconsin.  Finally  they  decided  to 
economize  money,  time,,  and  distance 
and  go  camping  fifty-four  miles  from 
home. 

They  went  in  Billy  Rumford's  seven- 
passenger  touring  car  and  Jerry  Ander- 
son's sedan,  leaving  behind  them  a 
much  peeved  community.  The  young 
husbands  were  so  much  in  love  with 
their  brides,  and  the  brides  were  so 
proud  of  their  husbands,  that  they  just 
simply  didn't  seem  to  have  any  use  for 
anybody  else.  It  was  the  "talk  of  the 
town;"  that  is,  the  society  end  of  things. 
Everybody  was  "good  and  sore."  Sev- 
eral of  their  outraged  friends,  among 
them  Charley  Patterson,  Burt  Morris 
and  Steve  Mayfair,  organized  them- 
selves into  a  "Punishment  Club,"  boldly 
announcing  the  vengeful  purpose  of 
their  constitution  and  by-laws  before 
the  departure  of  the  "tandem  trio." 

Billy  and  Helen 

"DILLY  RUMFORD  and  his  bride, 
-*-*  Helen,  a  girl  of  plain  appearance, 
but  compelling  wit  and  spirit,  sat  in  the 
front   seat   of  the  Touring  car.      Behind 


,i  Pictures  by 

Mi'  U  ,    CHARLES  A. 


"What's  this?     Listen  ..."  exclaimed  Billy. 

"Finest  silverware  you  ever  saw,''  one  of  the  voices  in  the  loud  speaker  was  saying. 
"Wonder  if  there's  not  some  diamonds  here  too." 

"Ray's  broadcasting  burglar  alarm  is  working!"  Alice  cried.  "There  are  burglars 
in  the  house!" 


folding  cots,  folding  chairs,  poles,  ropes, 
kitchen  utensils,  canned  and  cured 
foods,  vegetables,  and,  by  no  means 
least  of  all,  Billy's  locally  famous  radio- 
phone outfit  of  50-watts  power,  for  the 
removal  of  which  he  had  a  special  permit. 
In  the  sedan  rode  Jerry  Anderson  with 
his  pretty  bride,  Alice,  and  Carl  Frisbee 
with  his  timid  but  naively  brilliant  wife, 
Marie. 

All  went  well  until  about  five  miles 
from  their  camping  destination,  when 
the  engine  of  the  sedan  began  to  balk. 
The  three  young  husbands  worked  on 
it  for  an  hour,  but  were  unable  to  locate 
the  trouble.     At  last  Billy  said: 

"Let's  give  it  up  and  tow  her  the  rest 
of  the  way.  It's  getting  late,  only  three 
hours  till  sundown,  and  we've  got  the 
tents  to  pitch,  supper  to  get,  and  the 
radio  to  hook  up." 

This  was  agreed  upon,  and  a  tow  was 
arranged  with  the  skid-chains  of  the 
two  machines.  In  this  manner  they 
reached  their  camping  place  on  the 
shore  of  a  small  lake  in  a  wilderness  of 
woods,  with  the  nearest  house  half  a 
mile  away. 

Then  began  the  real  "speed  job"  of 
the  day.  Two  of  the  recent  bridegrooms 
pitched  the  tents  on  an  open,  grassy 
plot  near  the  lake  and  extended  a  single- 
wire     antenna     between     two    trees    on 


them  and   on   the   running   boards   was     opposite   sides  of  the   ISO-foot   clearing, 
packed    an    amplitude    of   tent   canvas,     with    insulators    beyond    the    reach    of 


the  branches.  The  other  husband, 
Carl  Frisbee,  built  two  fireplaces  with 
stones,  placing  over  one  a  metal  broiling 
grate  and  suspending  over  the  other 
a  kettle  from  a  stick-in-a-crotch  crane 
for  boiling  water.  Meanwhile,  one  of 
the  young  wives  aided  in  unloading  the 
touring  car,  setting  up  the  cots  in  the 
tents,  and  in  the  distributing  the  camp 
furniture,  while  the  other  two  prepared 
supper. 

Half  an  hour  after  sundown  the  camp 
was  "in  shape"  for  the  night,  and  a 
steaming  supper  was  on  the  folding 
table,  constructed  for  six  "in  a  pinch." 
In  the  illumination  of  the  automobile 
headlights,  they  ate  the  repast,  while 
a  smudge  near-by  served  well  to  keep 
the  mosquitos  away. 

A  Home-made  Outfit 

AFTER  supper  Billy  completed  the 
hook-up  of  his  radiophone.  Then 
he  jacked  up  the  rear  end  of  the  touring 
car,  took  off  the  rim  and  tire  of  one  of 
the  wheels,  and  substituted  a  rim  without 
a  tire.  A  few  feet  from  this  improvised 
sheave  wheel,  he  anchored  his  voltage 
generator  and  connected  them  with  a 
power  transmission  cable.  Then  he 
started  the  automobile  engine  and  soon 
was  generating  a  voltage  sufficient  to 
broadcast  a  hundred  miles  or  more. 

These  preparations  complete,  Billy 
began    to    tune    for    some     preliminary 


30 


RADIO  AGE/or  March,  1925 


musical  entertainment.  The  first  he  got 
was  a  bit  of  vaudeville,  broadcast  from 
a  Chicago  station.  A  song  of  mock- 
sadness  was  sung,  and  then  a  comedian 
began  to  broadcast  some  "wise  cracks," 
which  were  answered  naively  by  a 
character  introduced  by  the  joker  as 
Mr.  E.  Z.  Mark. 

"When  is  an  automobile  not  a  frog, 
Mr.  Mark?"  asked  the  fun  maker. 

"I  don't  know,  Mr.  Smart,"  replied  the 
other.  "When  is  an  automobile  not  a  frog?" 

"When  it  is  towed,"  replied  Mr.  Smart, 
whereupon  there  was  a  roar  of 
stage  laughter  from  a  group 
evidently  stationed  before  the 
microphone  to  produce  the  ap- 
plause of  an  "appreciative  audi- 
ence." 

"Oh,  don't  give  us  any  more 
of  that,"  protested  Jerry,  owner 
of  the  towed  automobile.  "See 
if  you  can't  find  some  opera 
music  that  will  harmonize  with 
the  voice  of  nature  around  us. 
I  resent  that  slur  on  my  sedan. 
Listen  how  beautifully  the  frogs 
are  singing  by  the  lake,  and  the 
crickets  and  the  katydids — " 

"Yes,  and  the  tree  toads,"  in- 
terrupted Jerry.  "Hear  that  one 
off  there?" 

"Off  where?"  demanded  Marie, 
tipping  her  head  first  to  the  right 
and  then  to  the  left  in  listening 
attitude. 

"You  can't  tell  directions  of 
the  'voices  of  the  night',"  said 
Helen  sharply.  "Didn't  you  ever 
try  to  locate  a  cricket  by  its  voice?' 

"Yes,  I  have,"  Marie  admitted;  ' 
it's  just   about   as   hard  to  locate   as  a 
katydid." 

"Or  a  frog,  or  a  tree  oad  or  a  whip-poor- 
will,  or  any  sound  broadcast  out  in  the 
open  country,  particularly  in  or  near  the 
woods,"  said  Carl.  "All  these  noisy 
animals  and  insects  are  broadcasters, 
don't  you  know?" 

"Yes,  and  you  need  a  radio  compass 
to  find  them,"  suggested  Helen. 

"Two  or  three  in  widely  different  posi- 
tions to  determine  their  latitude  and 
longitude,"  suggested  Billy  with  the 
expertness  of  an  experimenter. 

"They  make  me  think  of — of — burg- 
lars," said  Marie  with  characteristic 
timidness.  "Do  find  us  some  real  nice 
music,  Billy;  something  that  will  drown 
out  all  these  ghostly  noises." 

"Well,  we  don't  want  any  burglarous 
shivers  and  shudders  round  here,"  Billy 
decreed.  "I'll  see  what  I  can  find,"  he 
continued  as  he  began  to  twist  the  dials. 

"First,  see  if  you  can  pick  up  any  of 
our  friends  at  home,"  suggested  Alice. 

"Are  you  homesick  already,  Mrs. 
Anderson?"  demanded  Helen. 

"Not  at  all,  Mrs.  Rumford,"  flashed 
back  the  challenged  bride,  smartly;  "but 
maybe  some  of  the  folks  in  town  are 
talking  about  us." 

"Oh-ho,  Miss  Vanity — Mrs.  Vanity,  I 
mean!  You  know  the  old  saying  about 
people  who  listen  secretly  to  what  people 
say  about  them." 

"Hold  on,"  interposed  Jerry  with  mock 
challenge  in  his  voice.  "When  you  call 
my  wife  Mrs.  Vanity,  you  call  me  Mr. 
Vanity." 


The  Magazine  of  the  Hour 

There's  no  other  way  to  explain   that 
sort  of  talk." 

"Then  Ray's  broadcasting  burglar 
alarm  is  working,"  Alice  screamed. 
"There's  burglars  in  the  house.  Oh, 
my,  oh,  my!     What  will  we  do?" 

Chapter  II 

The  Microphone  Bullet  Eater 

(^  HOST-LIKE    silence    hovered    over 
^    the  camp  for  several  moments  after 


"Gee,  this  is  some  find!"  a 
heavy  voice  from  the  loud  speaker 
said.  " It' s  father' s  home!  Alice 
cried  with  a  picture  of  two  rough 
characters  in  her  mind. 


"Shame  on  you,  Jerry,"  put  in  Helen. 
'You're  an  ideal  husband,  you  are. 
That's  what  I  call  real  vanity.  Why 
don't  you  forget  yourself  and  defend  her?" 

"Here  we  are — stop  your  quarreling," 
announced  Billy.  "I  don't  know  what 
I've  got,  but  I've  got  something.  I 
tuned  to  get  your  brother  at  your  folks' 
home,  Alice,  but  there  are  strange  voices 
here." 

"Why,  my  folks  are  away,"  Alice 
replied.  "You  can't  get  anybody  there. 
They've  gone  to  Lake  Geneva.  I  thought 
I  told  you  that." 

"Is  that  so?  Well,  listen  here.  My 
goodness.     What's  this?     Listen." 

A  Voice  in  the  Dark 

Even  before  he  finished  his  excited 
utterances,  the  voices  in  the  loud  speaker 
were  becoming  more  and  more  distinct, 
with  awesome  foreboding. 

"Yes,  these  are  real  stuff,  solid  silver," 
one  of  the  voices  was  saying.  "Finest 
lot  of  silverware  you  ever  saw.  And  look 
at  this  pitcher — solid  stuff,  Bimbo,  and 
these  trays.  What  a  silver  mine!  Won- 
der if  there's  not  some  diamonds  here. 
Ought  to  be.  We'll  take  a  trip  to  Europe 
or  the  Sandwich  Islands  on  this  haul, 
Bim." 

"What  does  it  mean,  Jerry?"  Alice 
gasped,  seizing  her  husband's  arm. 
"Billy,  that  isn't  father's  home,  is  it? 
It  can't  be,  it  surely  can't  be." 

"I'm     afraid     it     is,"     Billy     replied. 


Alice's  panicky  declaration.  Helen  was 
the  first  to  break  it. 

"Oh,  you  must  be  mistaken,"  she  said, 
addressing  both  Billy  and  Alice.  "They 
wouldn't  be  so  foolish  as  to  broadcast  a 
confession  of  their  guilt  to  the  whole 
world." 

"They're'  not  doing  it  purposely," 
Billy  replied.  "But  maybe  you  don't 
fully   understand   Ray's  invention." 

"Oh,  yes,  I  do,"  Alice  insisted.  "He's 
described  it  to  me  several  times,  and  I 
can  recite  it  off  like  a  book.  He's  in 
Washington  now  perfecting  his  patent 
and  consulting  with  government  radio 
officials  on  his  automatic  shift  for  sending 
and  receiving,  which  makes  it  possible 
to  call  a  station  when  the  operator  is 
not  listening  in.  He  has  this  in  opera- 
tion at  home  in  conjunction  with  a  burglar 
alarm,  which  is  heard  by  every  listening 
amateur  in  range  of  his  transmitter  if 
burlgars  break  into  the  place." 

"Yes,  and  he's  had  the  device  in 
operation  only  a  short  time  and  hasn't 
explained  it  to  any  other  amateurs, 
except  me,  so  far  as  I  know,  for  fear  his 
patent  be  stolen  before  it  is  perfected," 
said  Billy.  "So  we're  the  only  ones  of 
all  those  now  listening  in  that  will  under- 
stand that  alarm  or  the  burglars'  con- 
versation. 

"The  device  is  simple,  but  ingenious. 
An  electro-magentic  wave  of  given  length 
and  impulse  serves  to  kill  a  magnet 
(Turn  to  page  70) 


RADIO  AGE  for   March,    1925 


What  the  Broadcasters  are  Doing        31 


Wkat  tke 
roadc  asters 
are  Doing 


Graduation  Held  Over  Radio 
at  WCCO 


GRADUATION 
air — that    is  t 


exercises  over  the 
air — that  is  the  latest  feature  from 
the  Gold  Medal  Station,  Minneapolis- 
Saint  Paul,  WCCO.  Wednesday,  Jan- 
uary 21st,  at  2:00  p.  m.  the  graduates 
of  the  first  Gold  Medal  Radio  Cooking 
School  received  their  diplomas,  listened 
to  the  Baccalaureate  address  by  Betty 
Crocker,  who  directed  the  school,  and 
heard  the  valedictorian  and  salutatorian. 

The  first  Gold  Medal  Radio  Cooking 
School  opened  on  November  4th.  Classes 
were  held  every  Tuesday  morning  over 
the  air,  when  Betty  Crocker,  Home 
Economics  Specialist  of  the  Station, 
instructed.  Approximately  2,000  women 
from  fourteen  states  registered  for  the 
course,  which  was  completed  December 
23d. 

In  order  to  graduate  and  receive  a 
diploma,  it  was  necessary  that  certain 
recipes  which  had  been  given  in  the 
classes  be  worked  out  and  reports  made 
on  them.  Although  the  school  ended 
at  a  busy  time  just  before  the  holidays, 
250  women  from  five  Northwest  states 
qualified  for  graduation. 

It  was  impossible  for  all  of  them  to 
come  to  Minneapolis  to  receive  their 
diplomas  during  the  graduation  exercises 
at  the  Gold  Medal  Station,  so  an  effort 
was  made,  Miss  Betty  Crocker  stated, 
to  have  at  least  one  representative  from 
each  state  there. 

The  graduation  exercises  were  similar 
to  those  conducted  by  the  average  schools, 
with  special  music  arranged  by  WCCO 
artists.  That  these  exercises  aroused  a 
large  amount  of  interest  among  the  women 
who  participated  in  the  course  is  evi- 
denced by  the  letters  received,  it  was 
said. 

One  Wisconsin  woman  wrote  in  that 
she  and  several  of  her  neighbors  had 
taken  the  course  and  met  in  her  home  on 
January  21  to  listen  in  on  the  graduation 
exercises,  and  said  she  had  a  new  dress 
made  for  the  occasion. 

The  oldest  student  in  the  class  was  an 
82-year  old  Minneapolis  woman.  She 
wrote  to  Betty  Crocker  that  she  was 
particularly  interested  in  completing  the 
work  and  graduating,  as  she  had  never 
before  graduated  from  anything  in  her 
life.  She  completed  all  of  the  work 
assigned  and  received  her  diploma. 

Two  blind  women  were  also  among 
the  students.  They  stated  that  the 
course  had  been  of  particular  value  to 
them  because  they  could  not  read  maga- 
zines and  get  the  suggestions  of  which 
other  women   make   use. 


Movie  Star    Meets  Doom 
Before  "Mike" 

J.WARREN  KERRIGAN,  widely 
known  motion  picture  star,  has 
faced  thousands  of  movie  cameras  without 
flinching,  but  he  admittedly  met  his 
Waterloo  lately  when  he  faced  the  mic- 
rophone of  Station  WGN,  located  on 
the  Drake  Hotel,  Chicago. 

Mr.  Kerrigan  was  schedulea  ..o  appear 
on  one  of  WGN's  afternoon  programs 
and  to  tell  of  his  experiences  while  engaged 
in  filming  "The  Covered  Wagcn,"  of 
which  he  is  the  star. 

Before  he  was  able  lO  get  launched 
into  the  topic  of  his  talk,  he  moved  his 
arm  and  unintentionally  shut  off  the 
microphone.  He  talked  for  fully  five 
minutes  before  it  was  discovered  that  his 
words  were  not  travelling  farther  than  the 
confines  of  the  velvet-lined  studio. 

Mr.  Kerrigan  was  told  to  start  all  over 
again — which  he  did.  "But,"  he  ex- 
plains, "from  then  on  I  was  all  upset 
I  stuttered,  gasped  and  said  things 
never  meant  to  be  said.  Finally  I  told 
Quin  Ryan  to  shut  off  the  juice.  The 
microphone   had   licked   me." 

(The  photo  of  Mr.  Kerrigan  above  is 
copyright  by  the  Drake  Studio.) 


Kiutus  Tecumseh,  a  full-biooded  Indian, 
prides  himself  as  the  "radio  representa- 
tive of  the  Red  Men,"  and  in  their  cause 
he  is  travelling  among  the  big  radio  sta- 
tions, singing  famous  Indian  melodies  and 
telling  i their  romantic  history.  He  is 
now  appearing  from   WEAF,  New  York. 


During  1924 

\  REVIEW  of  the  year's  operation 
-^*-  of  WGY,  the  Eastern  station  of 
the  General  Electric  Company  at  Schen- 
ectady, N.  Y.,  shows  that  the  station 
was  on  the  air  1,630  hours  during  1924, 
an  average  of  about  four  and  one  half 
hours  per  day. 

WGY  is  not  on  the  air  Wednesday 
evenings  except  on  very  rare  occasions, 
under  special  permit  from  the  radio 
supervisor,  and  Monday  evenings  the 
station  leaves  the  air  promptly  at  9 
o'clock,  at  which  time  WHAZ  of  Troy, 
N.  Y.,  is  licensed  to  hold  forth.  In  1923 
the  total  of  operating  hours  was  1,106. 

The  increase  of  operating  hours  for 
WGY  from  1923  to  1924  is  due  to  the 
expanding  activities  of  the  station  and 
also  to  the  broadcasting  of  the  national 
conventions  of  the  Republican  and 
Democratic  parties,  as  well  as  several 
campaign  speeches  by  the  presidential 
candidates. 

Efficiency  is  High 

-ne  efficiency  of  the  station,  during 
the  period  it  was  on  the  air,  was  99.99. 
This  record  speaks  well  for  the  watch- 
fulness and  expertness  of  the  radio 
engineers  who  are  responsible  for  the 
operation  of  the  station.  These  men  who 
are  never  heard  by  the  radio  audience 
are  responsible  for  the  quality  of  the 
transmitter  signals  and  on  their  alertness 
depends  the  continuity  of  the  program. 

During  1924  there  were  seven  sus- 
pensions of  broadcast  service  from  WGY 
due  to  apparatus  trouble  and  five  of 
these  breaks  in  program  came  during 
daylight  transmission.  The  total  time 
lost  was  thirty-six  minutes.  On  one 
occasion,  lightning  struck  the  antenna 
and  induction  burned  out  meters  and 
condensers.  Service  was  suspended  fifteen 
seconds,  the  time  required  to  bring  spare 
parts  into  commission. 


Tiny  Station  Shows  'Em 

Dreams  of  the  undergraduate  members 
of  a  little  class  in  radio  at  Knox  College 
at  Galesburg,  Illinois,  of  establishing  a 
Class  "A"  broadcasting  station  were 
fulfilled  during  February  as  a  result  of 
their  own  efforts  when  WFBZ,  the 
Siwash  station,  took  the  air  for  the  first 
time  and  broadcast  a  Knox-Monmouth 
basket  ball  game  to  nearby  States  with 
an  outfit  costing  but  $175,  which  made  a 
good  showing  within  a  radius  where 
there  were  many  stations  costing  from 
S10.000  to  860,000  sending  forth  their 
programs. 


32 


RADIO  AGE  for  March,  1925 


What  the  Broadcasters  are  Doing 


Down  the  Corridors  of  Time 


H  A  Breath  of  Old-World 
Romance  from  SBR,  Belgium 

YOU  do  not  need  to  get  your  thrill 
of  Old  World  romance  out  of 
pictures,  tales  or  travels  nowadays. 
Just  tune  in  on  265  meters  one  of  these 
unstatic  evenings  and  listen  to  a,  musical 
instrument  that  was  built  centuries  be- 
fore you  or  I  or  our  granddads  were  born. 
Tune  sharply  and  listen  carefully  and 
you  will  hear  M.  Marcel  van  Loust  de 
Borkenfeldt  announce  that  it  is  Station 
SBR,  Brussels,  Belgium. 

Lucky  are  you  if  you  cuance  to  tune 
in    on    one    of   those   evenings   that    M. 
Borkenfeldt  tells  you  that  the  next  num- 
ber will  be  a  carillon  solo  by   M.  Josef 
Denyn.     For   that   will   be  the  piece  de 
resistance  of  old  country  radio 
broadcasting.       M.    Denyn    is 
the  master  of  the  bells  in  the 
ages-old  tower  of  the  cathed- 
ral at  Malines.     Malines  is  the 
historic  town,   north  of   Brus- 
sels,   where    Cardinal    Mercier 
served  his  God  and  his  coun- 
try and  delivered  his  memor- 
able Phillipic  against  the  war- 
riors    who     executed      Edith 
Cavell.        Malines     made     its 
voice    heard    throughout    the 
world  eight  years  ago  because 
it   chanced   that   the    German 
gray-blue   hordes   passed   that 
way  into  France  and,  in  pas- 
sing, left  a  scar 

Like  Days  of  Old 

DUT  the  war  is  over  now 
-"-*  and  Belgium  is  the  old 
Belgium  of  the  days  when  the 
cafes  were  athrob  with  music, 
when  the  Grand  Place  at 
Brussels  was  a  rendezvous  for 
the  volatile  good  folk  and  the 
gardens  were  merry  with  wine 
women   and    song. 

But  the  carillon.  In  the  belfry  at 
Malines  are  stationary  bells  which  are 
"played"  by  M.  Denyn,  in  much  the 
same  manner  as  one  would  play  an  organ 
or  a  piano,  except  that  the  musical  con- 
trivance is  on  such  a  gigantic  scale  that 
no  ordinary  finger-board  is  sufficient  to 
exploit  it.  The  carillonneur  must  use  a 
keyboard,  called  a  clavier,  and  instead  of 
running  his  fingers  lightly  over  the  keys, 
he  must  pound  them  lustily  with  his  fists. 
An  old  authority  has  laid  down  the  rule 
that  a  "carillonneur  must  have  good 
hands  and  feet  and  be  free  from  the  gout." 

The  carillon  at  Malines  was  famous 
before  the  advent  of  radio  broadcasting. 
But  it  is  much  more  famous  since  radio 
carried  the  rich,  deep  music  of  the  enorm- 
ous bells  across  international  boundaries 
and  virtually  across  the  seven  seas.  M. 
Borkenfeldt  was  too  much  of  a  radio 
artist  to  overlook  the  value  of  the  Malines 
carillon,  and  when  I  visited  him  in  his 
broadcasting  station  in  Brussels  last 
Summer,  the  one  thing  about  which  he 


ft*  n  t\  ,■     *»•    *» 


Here  is  an  excellent  view  of  the  Malines  Cathedral,  at 
Malines,  Belgium.  The  chimes  broadcast  through  SBR  from 
the  tower  of  this  ancient  structure  have  literally  crossed  the 
seven  seas.  (Drawing  of  cathedral  by  Briant  Poulter  by  COW' 
tesy  of  "The  Architect,"  London.) 


By  FREDERICK  SMITH 


was  most  enthusiastic  was  his  plan  to 
broadcast  the  bells  of  Malines.  He  told 
me  he  would  do  it — and  how  astonishing 
has  been  his  success! 

Crossing  the  Atlantic 

TN  the  recent  international  tests  the 
■*-  bells  of  Malines  were  heard  as  far 
west  as  Salt  Lake  City,  Utah.  They 
have  been  heard  on  the  fringe  of  the 
burning  sands  of  Algeria  and  in  the 
winter  of  Helsingfors.  M.  Denyn  has 
good  hands  and  no  gout.  There  is  but 
one  broadcasting  station  in  Belgium. 
M.  Borkenfeldt  is  very  proud  of  it.  It 
is  owned  by  the  Radio  Belgiqu'e  Stock 
Company.  When  I  was  in  Brussels, 
the  directors  told  me  that  the  radio 
listeners  who  paid  their  government  li- 
censes to  listen  in  numbered  8,000  to 
9,000,  while  those  who  stealthily  tuned 
in     on     unlicensed     receiving    sets    num- 


M.  Borkenjetdt,  director  and 
announcer  of  SBR,  Belgium's 
onty  radio  station. 


bered  30,000  to  40,000  more.  Belgium, 
it  seems,  has  the  Old  World  policy 
of  making  the  fan  pay  for  his  enter- 
tainment. 

In  days  now  almost  prehistoric,  the 
carillon  was  limited  to  three 
or  four  bells,  but  the  num- 
ber of  bells  has  increased 
until  a  good  carillonneur  must 
have  reached  the  highest 
point  of  efficiency.  M.  Denyn, 
for  example,  is  known  as 
"The  Liszt  of  the  Bells." 
He  has  a  repertoire  that  in- 
cludes not  only  Flemish  music, 
but  old  English  folk  songs, 
Scotch  airs,  the  national  an- 
thems of  several  countries 
and  many  selections  from 
operas. 

M.  Denyn  is  a  good  deal  of 
a  "Roxy"  or  a  Jerry  Sullivan 
or  a  Harry  ,Snodgrass,  if  you 
will.  He  is  invited  to  go  to 
one  country  and  another  to 
play  the  local  bells,  and  every 
season  he  is  as  regular  in  his 
appearance  at  Dorset  as  are 
American  tourists  in  the  so- 
called  Sign  of  the  Cheshire 
Cheese  in  dear  old  Lunnon. 

So  keep  an  ear  perked  up 
for  M.  Borkenfeldt.  You 
may  hear  him  announcing 
from  "Bruxelles"  that  M. 
Denyn  is  about  to  stir  the 
echoes  in  the  ancient  belfry 
and  send  you  a  romantic  mo- 
ment all  the  way  down  the  corridors 
of    time. 

Doing  Fine,  Thank  You! 

T^HE  question   has  often  been   raised 


1 


concerning    Belgium's   confining  it- 


self to  only  one  radio  station.  M.  Bork- 
enfeldt explains  this  by  asserting  that 
his  countrymen  are  so  enthused  about 
Station  SBR  that  they  haven't  the  time 
or  the  inclination  to  grow  dissatisfied. 

His  innate  ability  to  prepare  varied 
programs  that  appeal  to  not  only  Bel- 
gians, but  listeners  in  all  the  surround- 
ing European  countries,  is  one  of  M. 
Borkenfeldt's  outstanding  accomplish- 
ments. Not  only  is  he  an  expert  pro- 
gram director,  but  a  keen  student  of 
technical  Radio  as  well. 

Truly,  he  is  one  of  the  few  predomi- 
nating radio  figures  that  have  sprung  up 
in  Europe  since  the  advent  of  broad- 
casting on  the  Continent. 

(Copyright:  1925:  by  Radio  Ago.  Inc.) 


RADIO  AGE  for  March,  1925 


"Zez^ 

Confrey 

Wrote 

"Kitten 

on  the 

Keys" 

But 

Here's 

the  Girl 

Who 

Can 

Play  it! 


What  the  Broadcasters  are  Doing        33 

How  "The  Girl 
With  the  Sum- 
mer-Resort Name" 
Bowled  Over 
the  Radio  Fans 
i  in    New     York! 


And  here's  Vee,  the  girl 
who  opened  a  radio  station 
all  by  herself — and  in  New 
York,  too! 


Gotham's  "Radio  Queen" 

AN  INTERVIEW  BY  WILLIS  ARNOLD 


NEW  YORK:— The  baby-queen  of 
Roxy's  Gang,  the  regular  Sunday 
night  spectacle  of  rythm  and 
artistry  broadcast  from  WEAF,  New- 
York  City,  has  no  greater  admirer — and 
a  secret  one  too — than  Joe,  the  night 
elevator  man  of  the  Capitol  Theater  Bldg., 
where  the  studio  is  located. 

Of  course,  Joe  has  his  ups  and  downs, 
but  he'll  tell  the  world  that  Vee  Lawn- 
hurst,  "The  Girl  With  The  Summer- 
Resort  Name,"  knows  jazz  from  J  to  Z. 

It  would  be  a  shame  to  say  that  Vee 
played  the  piano!  She's  got  a  natural 
born  gift  of  sitting  down  behind  the  keys 
and  making  every  little  do,  re,  mi,  trill 
out  a  Jolsonian  "Mammy"  that  would 
make  Al  turn  crimson  under  his  make-up. 
Zez  Confrey  wrote  "Kitten  on  the  Keys" 
— but  little  Vee  plays  it!  Indeed,  Irving 
would  go  back  to  Berlin  if  he  wrote  a  staff 
of  syncopation  that  Vee  couldn't  execute 
to  the  delight  of  every  charter  member  of 
the  Iwantadance  Club. 

Ask  the  average  radio  or  theatrical  star 
her  age  and  you  get  in   return  either  a 


scowl  or  a  misinterpretation  of  the  truth 
— but  again — it's  different  with  Vee. 
"I'm  nineteen"  she'll  smilingly  reply. 
"And  never  been  kissed?"  you're  just 
aching  to  ask  her — but  don't  dare! 

Her  First  Attempt 

"(~)H,  THAT  first  time  before  the  mike," 
^-'  Vee  will  tell  you,  "was  the  best 
and  the  worst.  It  was  2  o'clock  in  the 
morning,  and  they  had  just  finished 
Station  WGBS  here  in  New  York.  It  was 
the  first  testing  program,  and  never  a 
word  had  been  ushered  through  that 
microphone  before.  I  was  announcer, 
singer,  pianist — guess  I  was  the  whole 
show  that  early  morning! 

"But  I  was  just  as  scared  as  could  be! 
I  could  just  picture  millions  and  millions 
of  people  all  over  the  world  as  well  as  my 
own  circle  of  friends  located  near  the 
station  making  fun  of  my  tongue-tied 
antics. 

"That  sure  was  some  exciting  morning! 
'This  is  err  ....  Station  W  .  .  .  .  WG 
.  .  .  .  WGBS err  ....  a  test 


program'  were  the  first  words  that  I 
stuttered  and  faltered  through.  But  one 
sudden  and  happy  thought  saved  the  day. 
I  announced  myself  as  'Laura  Lawn- 
hurst' — even  said  that  she  would  favor  us 
with  a  piano  solo.  Then  I  hustled  off  to 
the  piano  and  played — -miserably!  Next 
I  announced  some  other  tricky  name  and 
said  she  would  sing.  Well,  she  didn't — 
though  honestly  she  tried  awfully  hard. 
And  so  went  the  little  monologue  on  and 
on,  for  ages  it  seemed! 

"It  was  a  test  program — and  some  test 
too!  Such  a  test  it  has  never  had  since, 
I'm  sure." 

But  Vee  is  inclined  to  be  a  six  letter 
word  meaning  reserved,  as  the  Cross-word 
Puzzler  would  say.  Modesty  is  a  prized 
virtue,  but  especially  so  when  Father 
Time  has  only  nineteen  short  years 
chalked  up  against  she  who  is  modest. 

Yet,  two  years  ago,  when  Vee  was  only 

seventeen,  she  was  the  star  jazz  pianola 

roll  maker  for  Ampico  and  other  leading 

companies.         That's     nothing!         She's 

(Turn  to  page  73) 


34         RADIO  AGE  for   March,    1925 


What  the  Broadcasters  are  Doing 


T 


he  Boys  Who  Rose  to  Vaudeville 
Fame  Are  Now  Real  Radio  Headline rs 


The  LOOS  BROTHERS 

Tell  How  They  Do  It 


Ernie   Loos,    who   can   sing   three    octaves 
without  flinching. 

IT  WAS  New  Year's  Eve— that  night 
of  nights  when  radio  stations  vie 
to  put  on  the  biggest  "show"  of 
the  year;  and  on  this  occasion  the  place 
was  the  crystal  radio  studio  of  Station 
WEBH,  located  on  the  Edgewater  Beach 
Hotel,  Chicago. 

A  tour  of  stations  throughout  the  city 
and  vicinity  revealed  that  nearly  every- 
one was  going  full  blast  at  midnight, 
with  a  galaxy  of  stars  that  rivaled  those 
to  be  found  on  the  most  pretentious 
legitimate  stage.  Every  station  had  its 
"exclusive"  artists,  doing  their  best  to 
keep  that  station  on  the  air  till  the  wee, 
small  hours  of  the  New  Year. 

The  Edgewater  Beach  Station  had  a 
group  of  sober  yet  peppy  artists  there, 
under  the  direction  of  Studio  Director 
Dean  Remick  and  Station  Director 
Robert  Boniel.  The  guests  at  the  hotel 
viewed  the  radio  artists  through  the 
glass  studio  with  the  eyes  of  persons 
who  were  used  to  such  things  and  thought 
them  perfectly  commonplace. 

The  Awakening 

BUT  shortly  after  midnight  people 
began  to  talk.  Did  you  see  those 
two  immaculately  evening-dressed  men 
— not  youngsters,  but  youngish  looking 
men,  who  just  entered  the  studio?    Later 


Unbroken  Partnership  with  Real  Understanding, 
Responsible  for  Success,   "Ernie  and  Billy"  Say 


they  sang  together  for  the  orchestra, 
and  then  they  hied  back  to  the  studio, 
and,  seated  cozily  in  front  of  the  studio 
piano,  they  reeled  off  crooning  jazz 
ditties  such  as  have  never  been  heard 
before.  Noses  were  pressed  against  the 
glass  wall  to  get  a  better  view  of  these 
veteran  entertainers  "in  action"  before 
the  microphone. 

Questions  revealed  the  information 
that  the  two  distinguished-looking  gen- 
tlemen were  brothers — Ernie  and  Billy 
Loos.  Ernie  is  the  big  fellow,  who  rolls 
his  eyes  when  he  sings  those  southern 
jazz  melodies.  Billy  is  the  little  one  who 
tickles  the  ivories  and  harmonizes  with 
a  deep  baritone  with  his  brother's  bass, 
or  tenor — for  Ernie's  equally  adept 
at  either. 

Ernie  and  Billy  appear  at  WEBH 
regularly.  They  have  appeared  on 
RADIO  AGE  programs  from  that  station 
with  great  success.  Their  advent  into 
radio  entertainment  is  only  recent,  but 
for  that  reason  radio  fans  should  not 
get  the  idea  that  the  Loos  Brothers  are 
new  to  American  music  lovers. 

On  the  contrary,  they  are  one  of  the 
best  known  "brother"  pairs  on  the  Amer- 
ican vaudeville  stage.  Strange  as  it 
may  seem,  the  Loos  Brothers  are  really 
brothers.  Their  respective  physiog- 
nomies, which  may  be  compared  to 
advantage,  prove  that.  And  again, 
strange  to  say,  these  brothers  have 
remained  together  for  nearly  two  dec- 
ades without  a  rift  in  the  ranks.  That 
is  indeed  an  accomplishment. 

Ernie  and  Billy  Loos  began  their 
careers  singing  illustrated  songs  for  their 
father,  one  of  Chicago's  first  motion 
picture  exhibitors.  However,  they  soon 
outgrew  their  father's  direction,  and 
branched  off  for  themselves.  They 
landed  long-time  contracts  with  the  old 
Sullivan  and  Considine  vaudeville  circuit 
and  later  became  a  permanent  institu- 
tion with  Keith's  circuit. 

Going  the  Rounds 

'  |  ''HEY  have  appeared  during  the  last 
-*-  ten  years  at  nearly  all  of  New  York's 
big  cafes  and  theatres,  and  until  recently 
they  were  "fixtures"  at  the  Marigold 
Gardens,  Rainbo  Gardens  and  with 
Isham  Jones'  orchestra  in  Chicago.  Now 
they    are    devoting    most    of    their    time 


to  entertaining  by  radio  for  big  song 
publishers.  Sooner  or  later  they  expect 
to  be  back  in  vaudeville,  for  as  Ernie 
says,  "It's  in  the  blood.", 

Ernie  Loos  sings  three  octaves  in 
tenor  and  bass,  and  some  persons  believe 
there  are  more  than  two  singing  when 
this  pair  start  their  vocal  contortions. 
Billy  plays  the  piano  and  sings  a  rich, 
full  baritone  that  has  won  him  wide 
commendation.  Of  course,  they  show 
to  the  best  advantage  on  the  stage,  but 
even  the  curtain  of  the  ether  fails  to 
shut  out  their  dominating  personality 
when  they  start  such  melodies  as  "Too 
Tired,"  "Broadcasting  Mamma,"  (one 
of  their  own  ditties)  and  "Oh,  Mabel!" 

So  popular  have  they  become  that 
persons  visiting  the  Edgewater  Beach 
Hotel  insist  that  the  Loos  boys  come  out 
of  the  studio  and  sing  to  the  gatherings 
in  the  Marine  Dining  Room.  And  of 
course  "the  bovs"  do  it. 


Billy  Loos,  who  can  sing  a  baritone  and 
play  the  piano,  too. 


RADIO  AGE  for  March,  1925 


What  the  Broadcasters  are  Doing         35 


Hazel  and  Her  Tantalizing  Fiddle 


THOUSANDS        of        people 
throughout  the  broadcasting 
area  of  radio  station   WBAP 
at  Fort  Worth,  Tex.,  adjust  their 
headphones  and  tune  in  their  loud  speak- 
ers each  Sunday  night  for  the  midnight 
concert,    knowing    that    unusually    good 
entertainment  awaits  them. 

Are  they  disappointed?  If  you  have 
ever  heard  Miss  Hazel  Boyer  and  her 
"tantalizing  fiddle"  at  this  period,  you 
can  easily  answer  that  question  for  your- 
self. 

To  play  effectively  to  a  countless  num- 
ber of  people  time  after  time,  never  failing 
to  bring  wires  and  long  distance  telephone 
messages  from  almost  every  state  in  the 
Union,  to  say  nothing  of  the  great  quan- 
tity of  mail  received  each  week,  is 
an  achievement  that  few  can  boast 
of.  Judging  by  the  applause  re- 
ceived by  Miss  Boyer,  she  is  with- 
out doubt  the  most  popular  radio 
entertainer  in  the  Southwest. 


At  an  Early  Age 

AT  THE  age  of  five  Hazel  began 
-1  *-  her  career  as  a  violinist  under 
the  able  teaching  of  her  mother. 
Unlike  most  little  girls  of  that 
tender  age,  she  did  not  take  her 
dollies  to  bed  with  her,  but  instead 
she  religiously  carried  her  violin  up 
to  her  room  each  night  and  went 
to  sleep  with  it  hugged  tightly  in 
her  arms.  Her  mother  would  slip 
quietly  to  the  bedside  and  remove 
the  fragile  instrument. 

One  year  later,  she  made  her 
first  public  appearance  in  recital 
before  friends.  She  was  warmly 
received  by  fellow  musicians  at 
that  time  and  a  successful  future 
was  predicted  for  her.  When  she 
was  still  a  child  of  ten,  she  at- 
tracted the  attention  of  serious 
musicians  who  assured  her  of  a 
future  of  success  and  brilliance  if 
she  would  only  work  to  that  end. 

Miss  Boyer  entered  the  profes- 
sional world  by  playing  at  the 
Union  Gospel  Mission  of  Fort 
Worth,  where  she  played  for  some 
time.  The  public  gasped  with 
astonishment  at  the  skill  the  child- 
wonder  showed  in  handling  her  in- 
trument.  This  engagement  brought 
forth  offers  from  various  sources 
outside  of  her  own  city,  some  of 
them  in  vaudeville.  All  were 
refused.  She  preferred  to  remain  in 
Fort  Worth  with  her  mother  and 
play  for  the  people  who  knew  and 
loved  her. 

Has  Own  Orchestra 


CHE  played  engagements  at  the 
^  most  prominent  clubs  and  at 
the  theatres  of  Fort  Worth,  later  organ- 
izing her  own  orchestra  and  playing  at  the 
Metropolitan  hotel.  She  is  playing  this 
season  at  the  Crazy  Hotel,  Mineral  Wells, 
a  Texas  health  resort  where  her  concerts 
are  broadcast  bv  remote  control. 


By  LERA  McGINTY 


{[This  Charming  Girl  Vio- 
linist Got  Her  Start  by 
Taking  a  Fiddle  to  Bed 
with  Her  Instead  of  a  Doll; 
Now  She's  the  Most  Pop- 
ular Radio  Entertainer  in 
the  Southwest;  Here's  Why 


Miss  Hazel  Boyer,  with  her  violin,  which  can 
radiate  jazz  and  classical  airs  with  equal  dexterity. 
If  you  doubt  Hazel's  popularity,  just  read  her 
mail  for  one  week! 


Most  of  Miss  Boyer's  radio  entertain- 
ment consists  of  that  much-talked-of 
"American  Folk  Music" — jazz.  That  is 
because  her  audience  demands  it  and  not 
because  it  is  the  only  class  of  music 
she  can  play.      Hers  is  a  rare  gift  that 


few  are  blessed  with,  for  she  is  so 
versatile  as  to  play  also  Mendels- 
sohn concerts  with  the  ease  and 
artistry  of  a  genius.  She  has  often 
been  told  by  artists  of  world  fame  that 
she  has  the  makings  of  a  Maud  Powell. 

To  be  talented  alone  is  wonderful,  but 
to  be  beautiful,  talented  and  the  pos- 
sessor of  a  smile  that  is  never  forgotten, 
is  indeed  a  gift.  It  is  an  established  fact 
to  those  who  know  her  that  her  ever- 
present  smile  and  pleasing  personality 
have  won  for  her  as  many  friends  as  has 
her  playing.  Just  how  gracious  she 
really  is  may  be  judged  by  the  following 
remark,  made  by  another  woman  musician 
of  ability:  "Hazel  has  had  praise  heaped 
upon  her  from  her  friends,  her  fellow 
musicians  and  musicians  of  note, 
yet  she  is  unaffected  and  the 
same  sweet  Hazel  of  childhood." 
She  also  laughingly  confided  this, 
"You  know  as  a  rule  that  praise 
goes  to  one's  head,  especially  to 
headsof  temperamental  musicians." 
Possibly  some  of  the  rest  of  us 
might  have  thought  this,  but  would 
never  dare  to  say  it.  The  spokes- 
man, being  a  musician  herself, 
however,  makes  it  all  right. 

r  I  ''HE  question  was  asked  as  to 
-*-  whether  or  not  Miss  Boyer  ex- 
pected to  attain  greater  things  with 
her  violin  than  she  has  done.  The 
answer  was  not  very  definite.  She 
said  home  ties  were  stronger,  but 
her  secret  ambition  seems  to  be  to 
do  concert  work  some  day. 

According  to  artists  who  should 
know  by  experience,  she  has  no 
cause  to  fear  the  struggle  experi- 
enced by  many  unknown  musicians 
just  beginning  the  upward  climb, 
because  she  is  a  genius,  and  a  genius 
is  soon  recognized  and  claimed. 

Besides  playing  her  "tantalizing 
fiddle"  Miss  Boyer  likes  to  dance, 
swim  and  read  radio  mail.  Of 
course,  she  cannot  acknowledge  all 
of  the  letters  received,  for  who 
would  play  the  fiddle  if  she  did? 

We  radio  fans  are  particular  who 
substitutes  for  a  favorite  artist,  and 
they  tell  her  daily  she  has  no  equal. 
Therefore  she  wishes  to  take  ad- 
vantage of  this  opportunity  to  tell 
you  that  her  mail  is  a  never-failing 
source  of  delight  to  her  and  how 
much  she  appreciates  the  generous 
response  accorded  her  each  Sunday 
night  by  her  listeners. 

Although  midnight  is  a  fairly  late 
hour  to  start  a  radio  program  on.a 
Sunday  evening,  Station  WBAP 
announces  that  judging  by  the 
number  of  requests  that  come  in 
after  midnight,  a  large  portion  of 
the  radio  audience  is  awake  and  listening 
at  that  hour.  WBAP  is  particularly 
popular  at  this  time  on  Sundays,  in  view 
of  the  fact  that  the  majority  of  the 
stations  throughout  the  country  "sign 
off"  about  10  o'clock. 


36         RADIO  AGE  for  March,  1925 


What  the  Broadcasters  are  Doing 

WBZ- 

The  Station 

of  Good 

CHEER 

A  Picture  from  Life 
By  MILTON  LIEBERMAN 


Miss  Ramona  M.  Nelson,  a  soprano  of 
note  and  incidentally  one  of  the  reasons 
why  WBZ  is  popular  among  the  males 
from  coast  to  coast. 

SPRINGFIELD,  Mass.— WBZ  was 
a  great  cheer-maker  in  the  land 
where  it's  always  WBZ — "  'Way  Be- 
low Zero,"  said  the  sailors  from  the  U.S. 
S.  Patoka  when  they  arrived  in  port  at 
New  York  recently.  They  had  just  come 
from  the  land  where  the  Esquimaux 
squat  in  their  snow  tepees  up  in  Arctic 
waters. 

They  were  referring  to  WBZ,  the  West- 
inghouse  Electric  Station  in  Springfield, 
Mass.  Part  of  the  programs  which  they 
heard  had  come  from  Boston,  where  the 
Herald-Traveler  operates  a  remote-con- 
trol studio  in  the  Hotel  Brunswick. 

"It  was  great,"  the  crew  said,  "to 
listen  in  to  the  ship's  radio  after  swabbing 
the  decks  with  chunks  of  ice  and  thawing 
out  our  beards  with  oxy-acetylene  torches. 
We  got  a  great  many  stations,  for  in  that 
land  of  white-washed  bears  and  cheap 
snow,  static  is  almost  nil  during  the  win- 
ter and  concerts  came  in  loudly.  But 
the  best  station  was  WBZ.  It  came  in  as 
clear  as  champagne  and  the  programs 
were  great." 

It  wasn't  long  after  WBZ  got  this 
message  from  the  thankful  "gobs"  before 
they  heard  from  the  state  of  Washington, 
where  lumber-jacks  in  the  fir-camps  had 
heard    them. 


"The  \ 

busiest 

person  in 

the  studio" 

is  the  title 

served  and  held  by  A. 

F.  Edes,  chief  announcer, 

program  dir ector,  host, 

etc.,  of  WBZ.     But  he 

treats  his  work  like  play. 


One  reason  that  the  sailors  and 
lumber  jacks  so  greatly  appreci- 
ated WBZ  was  because  through 
this  station  they  received  a  greater 
variety  of  programs  than  through 
any  other  station  in  the  country. 
It  has  thirty-two  special  wires 
and  two  permanent  remote-con- 
trol studios. 

The  two  permanent  ones  are  at 
the  Hotel  Kimball,  Springfield, 
Mass.,  and  in  the  Westinghouse 
studio  of  the  Hotel  Brunswick, 
Boston.  Boston,  incidentally,  is 
one  hundred  miles  from  Spring- 
field, and  a  two-way  wire  connects 
it  with  Springfield,  where  the  an- 
tenna towers  are  located. 

In  Springfield,  programs  are 
broadcast  by  special  wires  from  the 
Capital  Theatre,  Springfield  Audi- 
torium, State  Theatre,  Poli's 
Theatre,  Court  Square  Theatre, 
Springfield  Union,  Cook's  Butter- 


A  Big  Event 

THIS  happened  in  Independence, 
Washington,  where  one  of  the  radio 
bugs  ran  through  the  town  shouting  that 
he  had  heard  voices  from  the  East.  Im- 
mediately the  town  council  voted  this  as 


one  of  the  town's  most 
exciting  moments  since 
Lincoln  was  shot. 

No  wonder,  either, 
that  it  caused  a  great 
furor  in  the  land  of  trees, 
for  the  days  are  dull  and 
the  nights  lonely.  The 
husky  jacks,  many  of 
them  from  brilliant 
Broadway,  found  great 
solace  from  their  loneli- 
ness in  radio,  but  for  a 
long  time  they  heard 
only  the  western  sta- 
tions. It  was  conceded  by 
them  that  an  eastern  sta- 
tion would  be  a  God-send, 
and  when  WBZ's  thou- 
sand watts  came  flowing 
in  they  all  sat  down  and 
wrote  in  to  the  station. 


A  great  help  to  digestion  and  a  substantiation  of  the 
popularity  of  "Music  While  You  Eat"  is  the  Westing- 
house  Philharmonic  Trio  which  plays  several  times  a- 
week  from  the  Kimball  Hotel  studio  of  WBZ,  at  dinner- 
time. Gustave  LaZazzera,  cellist;  Mrs.  Eleanor  Turner 
LaZazzera,  pianist,  and  Gaetano  Misterly,  violinist. 


RADIO  AGE  for  March,    1925 

WBZ  May  Mean  "Way  Be- 
Low  Zero"  But  Its  Programs 
Have  Warmed  the  Hearts  of 
Arctic  Explorers  and  the  Men 
Far    Away  from    Home 


What  the  Broadcasters  are  Doing,        37 


fly  Dance  Palace,  Eastern  States  Exposi- 
tion, National  Institute  of  Musical  Art, 
Church,  and  South  Congregational  Unity 
Church.  In  Boston,  wires  are  run  to  the 
Boston  Arena,  Boston  Opera  House, 
Chickering  Piano  Building,  Colonial 
Theatre,  Convention  Hall,  Copley  Plaza 
Hotel,  Estey  Organ  Factory,  Hotel 
Lenox,  Hume  Music  Company,  Jordan 
Hall,  Kieth's  Theatre,  Majestic  Theatre, 
Mechanics  Building,  Plymouth  Theatre, 
St.  James  Theatre,  Shubert  Theatre, 
Steinart  Hall,  Symphony  Hall,  Tremont 
Theatre,  and  the  Wilbur  Theatre. 

This,  as  you  see,  gives  the  radio  public 
a  glimpse  of  sedate  Boston  in  all  its 
moods.  Jazz  and  sermons,  concerts  and 
prize  fights, — all  are  tapped  by  WBZ. 

If  WBZ  had  been  in  operation  in  the 
old  days,  you  probably  would  have  heard 
a  first-hand  account  of  the  famous  Bos- 
ton Tea  Party.  Let  us  picture  William 
S.  Tilton,  one  of  the  announcers,  stand- 
ing before   the 

microphone  on  the        wsimmmmmmmmitsmimmM 
evening  of  Decem- 
ber 16, 1773. 

"Thisisthe  Her- 
ald-Traveler stu- 
dio, WBZ,  broad- 
casting from  the 
Hotel  Brunswick, 
Boston,  Mass. 
There  was  a  little 
party  here  in  Bos- 
ton, folks,  and  we 
really  wish  that 
you  were  in  on  it. 
Especially  you 
lovers  of  the  well- 
known  tea  leaf. 
Mr.  Lipton,  who  is 
famous  as  a  tea 
farmer,  and  at 
times  yacht  racer, 
sent  a  supply  of 
tea  on  the  schooner 
Gaspee. 


TT  RAN  aground 
-*-  off  Providence, 
and  some  of  our 
leading  citizens, 
dressed  as  Indians 
in  their  charity 
ball  costumes, 
went  aboard  and 
took  possession. 
Amid  great 
gayety,  and  oc- 
casional exclama- 
tions, such  as 
'haven't  we  got 
fun,'  they  tossed 
boxes  of  the  tea 
overboard.  The 
reason  for  this  was 
that   the  Boston 


taste  for  coffee  was 
being  violated  by 
the  balmy  British, 
who  insisted  that 
we  take  their  tea. 
Their  insistence 
that  we  also  pay 
the  tax  on  it,  with- 
out due  represen- 
tation in  the  Brit- 
ish Parliament, 
was  irritating,  to 
say  the  least.  If 
we  were  privileged 
to  inflict  our  beans 
upon  England, per- 
haps feeling  would 
not  have  run  so 
high." 

Undoubtedly, 
also,  WBZ  would 
have  broadcast  a 
running  account 


E.  W.  Bach  is  an  announcer  at  WBZ, 
but  on  a  moment's  notice,  as  shown  above, 
he  can  step  be/ore  the  microphone  and  sing 
a  breath-taking  baritone  solo. 


A.  L.  S.  Wood,  dramatic  editor  of  the  Springfield  Union, 
shares  his  extensive  knowledge  of  the  American  stage  and  lit- 
erature with  radio  fans  regularly  from  WBZ,  where  he  pours 
authoritative  data   into  the  Hotel  Kimball  studio   microphone. 

When  you  hear  it  announced  that  you  are  going  to  be  taken 
around  to  the  theaters  and  introduced  to  this  or  that  stage  celeb- 
rity, you  know  "Al"  is  going  to  be  your  guide. 

of  the  landing  of  at  Springfield,  and  A.  S.  Eisenmann  is  the 

the  Pilgrims  on  associate   director.     John    L.    Ingram   is 

Plymouth  Rock,  if  chief  operator,  and  his  helpers  are  R.  F. 

they  had  been  in  Bloom,  Roger  Houghton  and  H.  R.  Dyson, 

existence  at  that  At  the  Kimball  is  E.  G.  Graton,  and  P. 

time,  for  the  WBZ  W.  Harrison  is  in  charge  of  operations  at 

boys  do  insist  on  Boston  with  P.  J.  Robinson  and  G.  W. 

getting  "scoops."  Lang  assisting. 

However,  it  is  a  WBZ  was  claimed  to  be  the  most  con- 
shame  to  com-  sistent  transmitting  station  in  the  United 
plain  that  these  States  by  the  Bureau  of  Standards,  which 
events  were  not  found  during  thirteen  measurements  that 
broadcast,  when  there  was  absolutely  no  deviation  from 
they  have  such  its  assigned  frequency, 
excellent  programs  During  the  Winter  WBZ  broadcasts 
now.  They  are  an-  educational  courses,  which  include  lessons 
nounced  by  in  modern  American  Literature  and  ap- 
Thomas  H.  Mc-  preciation  of  music.  The  courses  are  put 
Nally,  and  Alwyn  on  the  air  from  the  Hotel  Brunswick  in 

E.  W.  Bach,  be-  co-operation  with  the  Massachusetts  De- 
sides  Mr.  Tilton.  partment   of   Education. 

George   H.  Jas-  Robert   Emmons   Rogers,   professor  of 

pert  is  director  of  Englishliteratureat  the  Massachusetts  In- 

the  station,  and  stitute  of  Technology,  conducts  the  course 

other  members  of  in  modern  American  literature  and  delivers 

the  staff  include  A.  lecturesevery  Monday  at  7:30  p.  m.     Pro- 

F.  Edes,  the  Her-  fessor  Stuart  Mason  of  the  New  England 
aid -Traveler  rep-  Conservatory  conducts  the  musical  appre- 
resentative,  and  ciation  courses  every  Friday  at  7:30  p.  m. 
C.  M.  Burr,  West-  A  feature  of  which  WBZ  is  very  proud 
inghouse  an-  was  the  broadcasting  of  an  interview  with 
nouncer.  J.  B.  Jackie  Coogan  at  a  Kiwanis  luncheon. 
Coleman  is  the  en-  It  also  broadcast  the  arrival  of  the  round- 
gineer  in  charge ;  the- world  fliers  at  Boston,  and  every 
V.  A.  Breglio  han-  year  sends  the  Conference  of  New  Eng- 
dles  the   publicity  land   Governors  on   the  air. 


38  RADIO  AGE  for  March,  1925 


What  the  Broadcasters  are  Doing 


"Whit 


1 1 


The  Mystery 

MAN 
of  Boston 


By  Oliver 
JENKINS 


STATION  WEEI,  the  Friendly 
Glow,  Boston.  The  next  feature 
on  our  program  will  be  a  radio 
interview  by  'Whit'." 

And  forgetting  all  about  the  DX 
records  for  the  time,  the  million  and  a 
half  listeners  which  WEEI  figures  as  its 
average  unseen  audience  at  any  given 
time  when  its  program  is  on  the  air,  settle 
back  comfortably,  whether  in  chairs  of 
mohair  or  pine,  anticipating  a  half  hour  of 
unadulterated  enjoyment.  Needless  to 
say,  their  anticipations  are  always  realized. 

The  radio  interview  originated  with 
"Whit."  It  is  a  popular  feature,  for 
although  the  Boston  station  has  been  on 
the  air  only  four  months,  stations  all 
over  the  country  have  grasped  at  the 
idea  and  the  radio  interview  is  now  a 
prominent  attraction  on  many  programs. 

"Whit"  has  interviewed  statesmen,  act- 
ors, editors,  cartoonists,  radio  experts  and 
big  business  magnates — and  even  a  ghost! 
Readers  of  RADIO  AGE  havealready  read 
something  about  this  extraordinary  event, 
but  the  subject  simply  can't  be  passed  by 
without  the  mention  of  an  interesting  in- 
cident in  connection  with  it. 

Who's  the  Ghost? 

THE  "Ghost"  was  impersonated  by  no 
other  than  Charles  Burton,  the  super- 
intendent of  the  station.  It  isn't  a 
simple  matter  to  play  the  part  of  a  ghost; 
it  requires  a  little  thought.  But  no 
problem,  however  difficult,  can  baffle 
"Burt"  and  "Whit"  when  they  put  their 
heads  together.  A  handkerchief  was 
thrown  over  the  "mike"  and  the  rest  was 
easy.  Telegrams  poured  into  the  studio 
all  the  night  of  Hallowe'en  and  many  of 
the  senders  apparently  thought  the  ghost 
might  have  been  real,  even  in  this 
Twentieth    Century! 

"Whit's" — we  are  going  to  shatter  the 
secret  now — "Whit's"  real  name  is 
Lewis  S.  Whitcomb,  and  before  entering 
the  radio  field,  he  was  a  newspaper  man 
in  Boston.  He  is  today  Assistant  Super- 
intendent of  WEEI.  How  such  a  change 
took  place  within  a  few  days  is  unusual, 
to  say  the  least. 


Who  wouldn't  be  an  interviewer  if  he  could  have  such  charm- 
ing ladies  to  interview  as  Betty  Bronson?  "Whit"  is  here 
shown  prying  all  sorts  of  secrets  from  the  popular  movie  star. 

How  Station  WEEI  is  Putting  the  Friendly  Glow 
Into  Its  Broadcasting  by  The  Simple  Process 
of  Interviewing  "Celebrities"  for  Its  Million 
And   a    Half  Enthusiastic  Listener  -Admirers. 


Six  months  ago  "Whit"  was  getting 
along  very  nicely  as  radio  editor  of  the 
Boston  Post,  and  within  a  few  blocks  of 
him  was  his  old  friend,  Charlie  Burton, 
radio  editor  of  the  Boston  Herald.  The 
two  met  frequently,  quite  often  spending 
the  lunch  hour  together,  during  which 
time  they  would  exchange  stories  of  radio 
and  news  interest.  The  men  on  the  Pes/ and 
the  men  on  the  Herald  are  supposed  to  be 
bitter  rivals,  but  these  two  refused  to  be. 

One  day  a  rumor  went  the  rounds  of  a 
possible  new  radio  station  which  was 
being  planned  by  the  Edison  Company 
of  Boston.  The  next  day,  both  of  the 
friends  went  around  to  the  office  of  the 
company  and  applied  for  the  job  of  an- 
nouncer. Neither  one  knew  that  the 
other  had  done  so.  Meeting  a  few  days 
later,  Burton  casually  mentioned  the  fact 
to  "Whit"  and  "Whit"  mentioned  that 
he  had  done  the  same  thing. 

"There  's  not  much  chance  of  both  of 
us  getting  the  job,"  said  Burton.  "One 
of  us  is  going  to  be  out  of  luck." 

So  "Whit"  attempted  to  withdraw  his 
application,  but  the  company  refused  to 
allow  it. 

"I'll  tell  you,  Charlie,"  said  "Whit." 
"I've  got  an  idea.  It's  been  running 
around  loose  in  my  mind  for  days.  We 
newspaper  fellows  interview  people,  don't 
we?  Then,  why  not  try  the  same  thing 
over  the  radio?  Interview  interesting 
people.      It  ought  to  go  over  big." 

The  Problem  Solved 

"TT'S  a  humdinger  of  an  idea,"  agreed 

■*■  Charlie,  "and  that  solves  the  problem. 

If  I  get  the  job,  I'll  spring  the  idea  and 


let  you   do  the  interviews.     If  you  get 
the  job,  you  do  the  same  with  me." 

The  agreement  was  made  on  the  spot. 
Everything  was  fine,  after  all.  Neither 
guessed  that  things  were  going  to  be  even 
finer.  Two  days  later  both  of  them 
received  letters  offering  them  positions 
with  the  new  station.  Burton  went  on 
as  superintendent  and  "Whit"  as  assis- 
tant. The  station  had  been  running 
only  a  week  when  "Whit"  put  his  inter- 
view idea  into  action.  As  the  theatre 
people  say,  it  was  a  "riot." 

Some  people  are  swamped  with  ideas. 
"Whit"  is  one  of  these  people.  The 
interview  notion  did  not  end  things. 
"Whit"  has  decided  that  radio  can  pay. 
That,  of  course,  is  one  of  the  big  questions 
of  the  hour.     Well,  can  it? 

"Whit"  saysyes.  He'sgoingtoproveit. 
Within  the  pastfew  weeks  he  has  already 
put  the  station  on  a  partially  paying  basis. 
His  venture  is  just  in  its  infancy,  however, 
and  the  time  has  not  yet  come  to  tell 
whether  it  is  practical  or  not.  But, 
knowing  "Whit,"  we  haven't  any  fears. 

One  of  the  newest  stunts  to  be  tried 
by  him  is  "Moving-pictures in  relation  to 
the  radio  station."  The  pictures  show 
the  workings  of  the  station,  the  various 
studios  hooked  up  with  it,  and  some  of 
the  millions  of  people  who  listen  in.  The 
picture  is  woven  around  a  charming 
story  of  love  and  adventure,  and  will  be 
shown  soon  in  Boston  theatres.  Of 
course,  this  is  in  a  way  an  advertising 
stunt,  but  it  is  one  that  any  station 
might  use  profitably,  and  after  all  it  ia 
interesting  as  well  as  educational. 
(Turn  to  page  72) 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour         39 


For  Maximum  Tube  Mileage 

A  Two-Tube  Ultra  Audion 


By  JOHN  B.  RATHBUN 


OF  the  twenty-eight  radio  receiving 
circuits  known  as  ultra-audions, 
there  is  one  simple  circuit  that  is 
most  commonly  known  to  the  radio 
novice.  This  is  the  Gibbon's  ultra- 
audion,  alias  the  "Little  Wonder  Circuit," 
alias  the  "Radio  Demon,"  alias  the 
"Ultraphone,"  alias  the  "Gibbon's  Os- 
cillator." It  has  also  paraded  under  the 
peculiar  cognomen  of  the  "Carpet  of 
Bagdad,"  which  however,  has  nothing 
to  do  with  the  photoplay  of  that  name. 
In  fact,  every  time  that  any  dealer 
wishes  to  bring  out  a  simple,  cheap  and 
efficient  distance  getter,  he  drags  out 
the  old  Gibbon's  and  labels  it  with  his 
pet  name.  Results  are  about  as  certain 
with  this  little  outfit  as  is  possible  with 
any  simple  combination  of  variable 
condenser  and  single  inductance  coil; 
hence  it  is  ideal  in  its  own  sphere  of  use- 
fulness. 

One  thing  that  appeals  particularly  to 
the  poor  hook-up  editor  is  the  fact  that 
you  have  twenty-eight  chances  of  avoid- 
ing a  mistake  in  connecting  it  up;  in 
fact,  it  is  almost  impossible  to  get  it 
hooked  up  so  that  it  will  not  percolate  to 
some  extent  unless  you  should  get  the 
"B"  battery  across  the  filament  of  the 
tube.  Confidentially,  it  can  also  be  used 
as  a  transmitter  over  a  short  range  by 
connecting  a  microphone  in  the  ground 
circuit.  This  statement  will  probably 
bring  down  the  united  curses  of  entire 
neighborhoods  on  my  head  for  bringing 
it  to  our  readers'  attention,  but  I  thought 
you  ought  to  know  it.  Radiate?  I'll 
say  she  does.  When  the  village  pest 
starts  twisting  the  dials  of  this  outfit 
you  will  see  your  neighbors  climbing  up  to 
the  house  tops  taking  down  their  aerials. 

But  It  Works! 

TT  may  be  noisy  and  it  may  radiate, 
•*-  but  it  certainly  gets  the  DX.  Like 
every  other  circuit  having  distance 
getting  qualities,  it  is  noisy,  unstable, 
Blueprints  of  the 


Copyright:  1925 


A  New  Version  of  an 
Old  Reliable  Hookup 


and  not  particularly  selective  where  there 
is  much  strong  local,  but  it  will  reward 
you  by  pulling  in  stuff  that  you  would 
otherwise  only  read  about.  Dollar  for 
dollar,  and  tube  for  tube,  you  can  cover 
more  mileage  with  the  ultra-audion  than 
any  other  set  I  know  of,  and  it  is  on  this 
basis  alone  that  I  recommend  it.  For  a 
single  circuit  receiver  it  tunes  quite 
sharply,    and    is    selective   enough    when 


A  COMPLETE  BLUEPRINT 

SECTION  IN  THE 

ANNUAL 

A  thirty-two  page  blueprint 
section,  replete  with  tried  hook- 
ups and  sixteen  pages  of  blue- 
prints in  actual  color,  is  the  out- 
standing feature  of  the  RADIO 
AGE  ANNUAL  for  1925,  now  avail- 
able at  $1.00  a  copy.  You  can 
use  these  blueprints  as  real  work- 
ing drawings,  for  they  are  clear 
and  easy  to  follow.  Sixteen  pages 
of  blueprints  are  worth  many 
times  the  purchase  price  of  the 
ANNUAL. 

In  addition  to  the  blueprint 
section,  there  are  hundreds  of  new 
hookups  for  beginner  and  expert 
in  the  ANNUAL  for  1925.  Every 
class  of  radio  fan  will  find  his 
wants  fulfilled. 

The  first  edition  consists  of  a 
limited  number  of  copies,  which 
are  being  exhausted  quickly.  Send 
your  dollar  NOW  if  you  want  to 
be  assured  of  getting  your  copy 
of    the     RADIO    AGE     ANNUAL. 


fifty  miles  or  more  away  from  a  broad- 
casting station,  but  in  congested  local 
traffic  it  is  not  much  good,  and  in 
Chicago  it  is  practically  useless  except 
on     silent     nights. 

In  Chicago,  the  complete  set  of  parts 
have  been  sold  retail  for  $6.75  for  the 
single  tube  ultra,  and  from  §10.00  to 
$12.00  for  the  two  tube  set.  This,  of 
course,  does  not  include  headset,  tubes 
or  battery.  This  is  not  so  much  greater 
than  the  cost  of  building  a  crystal  set, 
except  for  the  tubes  and  battery,  and 
you  get  real  tube  results  with  a  few 
dollars  invested. 

I  do  not  recommend  the  single  tube 
ultra-audion  for  two  reasons.  (1)  Be- 
cause the  phone  impedance  forms  part 
of  the  inductive  balance  in  the  circuit 
which  is  upset  when  two  or  more  pair  of 
phones  are  inserted  into  the  detector 
circuit,  and  (2)  because  there  is  a 
considerable  body  capacity  effect  in  the 
phone  cords  when  the  headset  is  con- 
nected directly  to  the  detector  tube. 
By  using  an  audio  transformer  as  the 
inductance  for  the  first  tuoe,  we  do 
away  with  both  difficulties  and  the  re- 
ceiver is  therefore  much  more  flexible 
in  regard  to  the  output  connections. 
A  single  tube  ultra  will  not  carry  two 
sets  of  phones  satisfactorily,  either  in 
series  or  in  parallel,  for  this  varies  the 
feed-back  potential  and  therefore  the 
degree  of  regeneration.  When  working 
full  blast  on  distance,  the  phone  cord 
capacity  may  be  so  great  that  the 
station  will  be  tuned  in  or  out  every 
time  that  you  move  your  head  or  touch 
the  headset  with  your  fingers,  but  the 
introduction  of  an  audio  transformer  and 
second   tube    will    prevent    this   trouble. 


Wide  Meter  Range 

TN  Fig.  1  is  a  picture  diagram  of  the  two 

■*•  tube  ultra-audion   using  a  spiderweb 

coil  or  "pure  inductance"  for  the  tuning 

(Turn  to  page  42) 

Two-Tube  Ultra  Audion  on  Two  Pages  Following 


f?/40/O  s46£ 


V — r-7 


4E/Z//IL   \  I  / 


F/eJ 
Plan  View  of  Ul.tra-j4ud/on 

IN  OPOE/?  TO  SHOW  THE  OUTPUT  CO/V/VECT/O/YS POP 
E/THEP  UlC/fS  0/?S//VO//VS  POSTS  AS  M4Y  BE  DE- 
S/PEOj  WE  SHOW  POSTS  //V  F/G.t ' /}ND  i/rfCST  IN  E/G.  S. . 


OUTPUT 
BIND.  POSTS 


OUTPUT 
SINS.  GIRO.  JACK 


COFrfflGHT  /BBS" 
/?AD/0  AGE,  //VC. 
CH/CAGO,  /LL. 


F/6.2 
SCHEMATIC  DIAGRAM  of 
Ultra-Audion 

SHOWIN6  /?ECE/I/E/?  WITH  ONE  STAGE  OP 
/)(/D/0  A/VD  EOU/P'F'ED >  WITH  Tp-AAfS/V/T- 
TEP'EOP'  SHOP,T-/&J/YGE&4D/OP'//0WE. 


U.&.  /?A!  T-///SUAV 
C/A~/0 


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1 — 1. 

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is?* 


42        RADIO  AGE  for  March,  1925 

A  New  Version  of  the 
Ultra  Audion 

(Continued from  page  39) 

un.t.  This  type  of  coil  is  far  supei.or 
to  the  common  homemade  coil  wound  on 
a  tube.  With  a  23  plate  or  0.0005  mf 
variable  condenser  (C),  the  range  will 
be  from  200  meters  to  well  over  700 
meters  with  the  specified  coils.  It  will 
be  well  to  use  a  vernier  type  of  condenser 
so  that  the  maximum  signal  strength 
can  be  more  easily  developed  by  closer 
tuning. 

When  a  spiderweb  coil  is  usei-,  suc_ 
as  supplied  by  our  advertisers,  a  total 
of  eighty-five  turns  should  be  specified, 
tapped  at  such  points  as  will  properly 
cover  the  range  of  wavelengths.  The 
tap  switch  (TS)  makes  closer  tuning 
possible  over  a  greater  wavelength  range 
than  an  untapped  coil,  but  a  plain  coil 
can  also  be  used  with  a  total  of  75  to 
100  turns.  A  75  turn  or  a  100  turn 
honeycomb  coil  will  be  right,  but  the 
100  turn  is  probably  the  better  for  the 
broadcast  listener  with  wavelengths  aver- 
aging about  360  meters.  This  is  one  of 
the  advantages  of  the  ultra-audion;  it 
can  be  used  over  a  very  broad  band  of 
wavelengths  by  simply  substituting  coils 
of  various  numbers  of  turns.  Special 
tapped  honeycombs  can  be  used  as  well 
as  the  plain,  untapped  variety.  Tapping 
is  not  a  necessity  but  simply  a  convenience. 
When  the  coil  is  wound  on  a  cardboard 
tube,  a  diameter  of  from  2.5  inches  to 
3  inches  can  be  used,  and  we  should  have 
about  120  turns  tapped  at  about  ten- 
turn  intervals  after  the  fiftieth  turn. 
Thus,  we  will  tap  at  60  turns,  70  turns, 
80  turns,  90  turns,  100  turns,  110  turns 
and  at  the  finish.  This  will  give  us  seven 
tapping  points,  including  one  end.  To 
conserve  space  use  No.  26  D.  S.  C.  wire, 
but  if  desired,  No.  24  or  No.  22  can  also 
be  used.  The  low  loss  idea  can  be 
introduced  by  giving  the  coil  a  good  coat- 
ing of  celluloid  varnish  (not  shellac), 
and  then  slipping  the  coil  off  of  the  tube 
when  dried.  The  varnish  can  be  made 
by  dissolving  bits  of  celluloid  in  amyl 
acetate,  which  produces  a  fairly  good 
non-capacitative  coating.  If  shellac 
is  used,  you  will  get  no  results  at  all. 
The  paper  tube  can  be  slit  lengthwise 
before  winding,  and  when  the  coil  is 
dry,  we  can  easily  separate  it  from  the 
tubeby  breaking  down  the  latter  at  the  slit. 
Now  comes  an  important  precaution 
against  body  capacity.  The  stator  or 
stationary  plates  (s)  of  the  variable 
condenser  (C)  should  be  connected  to 
the  grid  line  (5)  while  the  rotor  or  moving 
plates  should  be  connected  to  ground  or 
to  line  (23).  If  this  is  not  done,  you  will 
be  annoyed  with  "body  capacity"  so  that 
when  you  put  your  hand  anywhere  near 
the  dial  it  will  detune  or  give  a  shrill 
"Whee-ee-ee"  and  break  into  violent 
oscillations. 

For  the  best  results  the  grid  condenser 
(K)  should  be  a  variable  condenser  or 
one  of  the  semi-variable  grid  condensers 
now  placed  on  the  market  for  this  pur- 
pose. When  the  capacity  is  once  adjusted 
to  the  requirements  of  the  particular  tube 
in  the  socket  it  does  not  frequently  need 


readjustment  except  on  wide  variations  of 
wavelengths,  and  the  latter  type  of  con- 
denser is  perfectly  correct.  However,  a 
fixed  condenser  of  0.00025  mf  capacity 
will  do  very  nicely  and  is  used  in  most  of 
the  ultra-audions.  A  variable  grid  leak 
at  (GL)  must  be  used  under  all  condi- 
tions as  the  tube  is  very  critical  to  the 
resistance  of  the  leak. 

The  Plate  Voltage 

1VTOW  just  a  word  in  regard  to  the 
J-^l  voltage  of  the  "B"  or  plate  battery 
(B).  If  we  are  to  avoid  excessive  radia- 
tion from  our  aerial,  and  reduce  inter- 
ference to  a  minimum,  we  must  nor  use 
over  22.5  volts  on  the  detector  tube  (Tl). 
This  result  is  attained  by  taking  an  inter- 
mediate "B"  battery  tap  at  the  point 
(+22)  at  the  22-volt  section  of  the 
battery,  as  shown.  If  maximum  amplifi- 
cation   is    required     without     regard    to 


Working  Blueprints 
of  this  famous 

ULTRA-AUDION 
HOOKUP 

Are  to  be  found  on 
pages  40  and  41 

Another  set  of 

BLUEPRINT  SURPRISES 

in  April   RADIO  AGE 


radiation,  then  we  can  put  the  full  "B" 
voltage  on  both  tubes  by  connecting 
(  +  B)  of  the  transformer  with  the  (+67) 
of  the  battery  by  means  of  the  wire  (22). 
If  you  love  your  neighbors,  don't  do 
this  anywhere  except  in  the  country 
where  you  are  at  least  five  miles  from 
the  nearest  receiving  set.  At  least  45 
volts  should  be  used  on  tube  (T2)  and 
preferably  from  67.5  to  90  volts  so 
that  we  gain  the  maximum  audio  amplifi- 
cation. The  high  voltage  on  ,(T2)  has 
no  radiating  effect. 

Owing  to  the  fact  that  iull  contro. 
of  the  regeneration  is  had  by  the  adjust- 
ment of  rheostat  (Rl)  it  is  sometimes  a 
good  policy  to  make  this  a  vernier  rheo 
stat,  but  fair  results  will  be  obtained 
from  a  plain  rheostat  of  the  proper 
resistance.  The  rheostat  (R2)  is  not 
critical  and  any  type  can  be  used  here. 
The  resistance  of  the  rheostats  depends 
upon  the  type  of  tube  used.  Any  tube 
can  be  used  for  the  detector  (Tl)  but 
the  amplifier  (T2)  must  be  some  hard 
amplifier  such  as  the  "11, ""12, ""199,"  or 
"201  A"  type.  For  small  sets  the  "11" 
and  the  "12"  tubes  work  very  well,  but 
of  course  the  201A  is  preferable  where  a 
storage  battery  is  justified.  The  soft 
"200"  tube  is  probably  a  more  sensitive 
detector  at  (Tl)  but  it  is  more  critical 
and  difficult  to  manage  and  also  takes 
more  current  than  the  other  tubes. 

Any  good  make  of  audio  transformer 
can  be  used  at  (AT)  with  a  ratio  of  from 
5-1  to  6-1.  This  single  stage  of  audio 
amplification    is    sufficient    to    get    good 


The  Magazine  of  the  Hour 

volume  on  distance,  and  with  local 
station, s  very  good  loud  speaker  volume 
can  be  obtained.  In  fact,  I  have  had 
fair  loud  speaker  volume  on  local  with 
the  detector  tube  alone,  so  intense  is 
the  regeneration  in  the  ultra-audion 
circuit.  The  output  (p-p')  is  connected 
to  the  phones  or  speaker,  as  may  be 
desired.  No  jack  has  been  placed  be- 
tween the  detector  and  audio  stage,  as 
this  would  introduce  "unbalance"  into 
the  circuit  and  also  give  phone  cord 
capacity  effect,  which  is  disastrous  to 
proper  performance. 

Only  a  very  small  panel  is  required, 
and  the  set  has  been  assembled  satis- 
factorily on  a  6"xl0"  and  6"xl2"  size 
with  plenty  of  room  for  all  of  the  parts. 
Its  portability  is  a  great  feature  and  the 
small  panel  permits  of  placing  batteries 
and  all  in  a  comparatively  small  cabinet, 
thus  making  the  set  self-contained  and 
handy  to  move  about.  When  the  detector 
is  used  alone,  without  audio  amplification, 
a  6  x7  or  a  7  x9  panel  will  be  ample 
for  the  accommodation  of  the  parts. 

In  regard  to  the  tap  switch  (TS),  I 
wish  to  say  that  the  number  of  contact 
buttons  used  will  depend  upon  the  num- 
ber of  tapping  points  on  the  coil  and  this 
is  likely  to  vary  somewhat  among  differ- 
ent makes  of  coils.  I  have  shown  seven 
taps  on  the  drawings,  but  this  must  be 
regulated  by  the  coil  used.  Some  com- 
mercial honeycombs  use  five  taps,  others 
use  seven  taps  and  there  are  coils  with 
nine  taps.  It  should  be  understood 
that  the  number  of  taps  connected  to 
the  contacts  is  one  less  than  the  total 
number  of  wire  ends,  since  one  end  of 
the  coil  is  permanently  connected  to 
the  aerial  by  wire  (1). 

In  Fig.  1  is  the  picture  diagram  by 
which  the  most  inexperienced  should  be 
enabled  to  hook  up  the  set.  Fig.  2  is  a 
conventional  drawing  using  symbols, 
while  Fig.  3  is  an  isometric  view  showing 
the  back  of  the  panel  and  the  arrange- 
ment of  the  apparatus  as  it  actually 
appears,  but  it  should  not  be  used  in 
making  the  actual  connections,  as  some 
of  the  wires  and  connections  are  hidden 
from  view.  For  making  connections,  use 
either  Fig.  1  or  Fig.  2.  An  isometric  is 
very  useful  for  gaining  an  idea  of  the 
general  arrangement  of  the  parts  and 
main  runs  of  wire,  but  if  it  is  made  so 
that  all  of  the  wires  are  in  plain  view, 
then  the  view  is  so  distorted  that  its 
principal  value  is  destroyed.  All  sense  of 
proportion  and  scale  are  lost  in  this  way. 

I'M  GENERAL,  it  is  best  to  place  a 
-*-  spiderweb  coil  (LI),  or  "pure  induct- 
ance" as  it  is  sometimes  called,  at  right 
angles  to  the  condenser  (C),  for  by  this 
arrangement  practically  all  electrostatic 
coupling  between  the  parts  is  eliminated. 
The  audio  transformer  should  be  kept 
awaj'  from  (LI)  to  prevent  noise.  It 
seems  almost  unnecessary  to  state  that 
all  connections  must  be  soldered,  and 
soldered  without  acid,  but  I  will  say  it 
anyway  for  the  benefit  of  the  beginners. 
Now  for  the  transmitter  attachment 
which  will  get  you  into  trouble  sooner  or 
later  if  you  do  not  have  an  experimental 
or  amateur's  license.  The  transmitter 
(Turn  to  page  71) 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour        43 


Conserving  Energy  with 

A  Regenerative  Reflex  Circuit 

By  JOHN  B.  RATHBUN 


REFLEX  circuit  experimenters  are 
divided  into  two  camps.  First, 
those  who  are  adherents  of  the 
•crystal  detector,  commonly  known  as 
the  "Tube  Conservationist  Party,"  and 
second,  those  who  believe  in  the  use  of 
the  standard  three-element  tube  as  a 
•detector,  and  derisively  called  the  "Howl 
Hounds." 

There  are  arguments  in  favor  of  both 
methods,  but  when  it  comes  down  to  the 
final  analysis,  it  is  not  so  easy  to  give  an 
opinion  as  to  the  merits  of  either  side. 
In  fact,  I  am  very  glad  I  am  not  in  a 
position  to  take  a  stand  one  way  or  the 
other  and  have  declared  a  condition  of 
neutrality  so  far  as  these  columns  go. 

There  are  those  who  go  so  far  as  to 
state  that  a  reflex  circuit  never  functions 
properly  until  there  is  at  least  some  re- 
generation in  the  radio  frequency  stage, 
and  if  this  is  the  case,  why  not  carry  out 
the  regenerative  idea  throughout  and 
dispense  with  the  crystal?  The  other 
party  to  the  argument  claims  clearer 
reception,  but  when  you  come  right  down 
to  the  bottom  of  the  matter,  the  principal 
objective  is  the  elimination  of  the  de- 
tector tube  and  conservation  of  the 
"battery  current.  So  it  goes.  As  reflex 
•circuits  with  crystal  detectors  have  been 
presented  time  and  time  again  in  RADIO 
AGE,  I  am  going  to  hand  you  a  circuit 
this  time  which  employs  a  three  element 
tube  detector  and  which  works  this  de- 
tector to  the  limit  of  its  capabilities; 
that  is,  the  detector  tube  will  be  made 
regenerative  so  as  to  squeeze  out  the  last 
drop  of  blood  remaining  in  it. 

Advantages  as  Detector 

ALWAYS  remembering  that  I  am 
neutral  (?)  I  will  start  the  ball  rolling 
"by  stating  the  following  advantages 
■claimed  for  the  tube  as  a  detector.  (1) 
A  standard  detector  tube  is  capable  of 
considerable  amplification  within  itself, 
-while  a  crystal  detector  cannot  amplify. 
(2)  A  tube  detector  can  be  made  re- 
generative, which  adds  still  further  to 
the  range  and  signal  strength.  (3)  The 
use  of  a  tube  detector  eliminates  "cat- 
-vvhisker  punching"  from  the  game  of 
radio  hide-and-seek,  and  this  is  truly  an 
advantage.  (4)  Properly  installed,  a 
tube  tends  to  stabilize  oscillations  in  the 
xadio  frequency  circuit  (Perhaps).  _  (5) 
That  the  detector  tube  is  so  efficient 
-when  regenerative  that  it  gives  just  as 
much  volume  as  one  reflexed  tube  with 
a  crystal;  therefore  there  is  no  real  tube 
or  battery  economy  when  a  crystal  is 
used.  In  other  words,  one  two-tube  set 
■withatube  detector  will  give  just  as  good 
performance  as  two  reflexed  stages  with 
a  crystal  detector,  so  what  is  the  use  of 
the  latter?  (6)  That  a  crystal  detector  is 
not  a  perfect  rectifier  as  so  often  claimed, 
and  that  it  introduces  just  as  much 
distortion  and  noise  as  an  improperly 
adjusted  tube  detector  if  not  more. 
There  you  are;  choose  for  yourself. 

While  all  of  the  above  statements  are 
academically,  correct,  it  is  not  _  always 
so  easy  to  make  them  work  out  in  prac- 
tice. I  have  seen  some  tube  detector 
reflexes  which  were  wonders,  and  then 
there  were  others  which  were  far  from 
having  this  distinction.  I  have  seen  two- 
tube  reflexes  (with  a  detector  tube)  .which 
-would  put  a  three  tube  and  crystal  de- 
tector outfit  to  shame,  both  as  to  clarity 


Getting  the  Most 
From   Your  Detector 

and  range,  and  then  I  have  seen  the 
reverse.  It  depends  a  good  deal  upon 
who  builds  the  circuit  and  how  it  is  put 
up.  I  have  seen  both  circuits  howl  with 
considerable  vigor,  and  the  tube  detector 
has  nothing  on  the  crystal  when  the 
latter  is  out  of  adjustment. 

It  might  be  well  to  remark  at  this  point 
that  a  soft  gas  detector  tube  seems  to  be 
more  effective  in  stabilizing  the  circuit 
than  a  hard  tube,  so  a  soft  tube  should 
be  used  as  the  detector  when  possible. 
Probably  one  of  the  best  tubes  from  this 
standpoint  is  the  "sodion"  tube,  which 
really  does  cut  down  the  oscillating 
tendency  to  a  marked  degree.  Then  do 
you  remember  the  little  Welsh  (501-D) 
tubes  with  the  filament  wrapped  around 
the  outside?  These  were  quite  good 
detectors  for  this  sort  of  circuit,  but  they 
lacked  the  sensitivity  of  the  sodions  and 
the  volume  was  less.  These  tubes  were 
not  oscillators  and  could  not  be  made 
regenerative,  but  they  were  far  more 
effective  than  a  crystal  and  were  much 
quieter. 

The  Circuit  Itself 

NOW  we  come  to  the  actual  circuit 
which  is  illustrated  by  the  accom- 
panying blueprints,  Figs.  1,  2,  and  3, 
which  are  respectively  the  picture  dia- 
gram, the  conventional  symbolic  diagram 
and  the  isometric  view.  These  pictures 
and  diagrams  are  clear  enough  for  the 
class  of  amateurs  I  am  appealing  to  with- 
out the  use  of  extensive  description,  for 
I  believe  that  this  job  should  be  tackled 
only  by  those  who  have  had  previous 
experience  in  building  reflex  circuits. 
It  is  not  so  difficult,  but  it  does  need  that 
experience  by  which  we  can  make  ad- 
justments by  the  sound  of  the  disturb- 
ance. Some  of  the  bypass  condensers 
are  likely  to  be  rather  critical,  and  with 
some  makes  of  transformers,  it  may  be 
necessary  to  change  the  values  of  the 
units  from  those  given  here. 

Tube  (Tl)  is  the  amplifier  tube  which 
amplifies  at  both  radio  and  audio  fre- 
quencies, and  therefore  this  must  be  a 
hard  tube  similar  to  the  UV-199  or 
UV-201A.  Tube  (T2)  is  the  detector 
tube  and  can  be  anything  that  we  may 
choose  to  use  in  the  tube  line.  Either 
a  hard  or  soft  tube  can  be  used  as  a  de- 
tector with  the  preference  in  favor  of  a 
gas-filled  sodion  type.  The  rheostats 
(Rl)  and  (Rl)  must  be  adapted  to  the 
tubes  used,  and  if  controls  are  to  be  at  a 
minimum,  an  amperite  can  be  used  in 
the  filament  circuit  (Rl)  of  the  amplifier 
(Tl),  but  a  rheostat  must  be  always  used 
with  (T2)  as  the  filament  adjustment 
for  this  tube  is  rather  critical.  Just  as  a 
suggestion  as  to  how  an  automatic  fila- 
ment control  can  be  used  with  an  ampli- 
fier tube,  I  have  indicated  an  amperite 
at  (Rl)  in  place  of  the  more  usual  rheo- 
stat, but  the  rheostat  can  be  substituted 
if  desired.  An  automatic  filament  con-, 
trol  gives  us  just  one  less  adjustment 
to  bother  with,  and  when  once  right,  it 
remains  right. 

At  (L1-L2)  we  have  the  usual  aperiodic 
coupler  consisting  of  about   IS  turns  on 


Blueprints  for  the  Regenerative  Reflex  on  Two  Pages  Following 


the  primary  coil  (LI)  and  from  55  to  60 
turns  on  the  secondary  coil  (L2).  The 
coils  are  separated  by  about  5-8  inch  for 
selectivity  and  are  wound  on  a  three 
inch  diameter  tube  with  No.  26  D.  S.  C. 
wire.  The  secondary  is  tuned  by  the 
0.0005  mf  variable  vernier  condenser 
(CI).  This  concludes  the  tuning  unit. 
The  output  of  the  amplifier  tube  (Tl) 
passes  through  the  primary  of  the  radio 
frequency  transformer  (RFT),  and  the 
secondary  of  this  transformer  forms  the 
detector  circuit  of  the  detector  tube 
(T2).  We  can  have  either  an  untuned 
transformer  at  this  point  or  an  air-core 
transformer  of  the  neutrodyne  type  with 
a  condenser  tuned  secondary,  but  for 
the  sake  of  simplicity  in  the  controls 
(RFT)  is  shown  of  the  untuned  type 
which  will  give  good  results  on  the  aver- 
age broadcasting  wavelength  range  of 
200  to  600  meters.  A  tuned  transformer 
gives  us  slightly  more  amplification,  but 
it  runs  up  our  controls  to  a  total  of  three, 
and  this  is  not  always  desirable  in  a  set 
of  this  kind. 

As  shown,  regeneration  in  the  detector 
tube  circuit  is  had  by  the  plate  variometer 
(VA)  which  tunes  the  plate  of  the  de- 
tector into  resonance  with  the  grid  cir- 
cuit. This  not  only  increases  the  range 
and  volume  but  it  also  helps  in  obtaining 
selectivity.  In  place  of  the  variometer 
we  can  also  use  a  "tuned  impedance" 
in  the  plate  circuit  consisting  of  a  0.0005 
mf  variable  condenser  with  a  50  turn 
honeycomb  coil.  This  is  for  the  benefit 
of  those  readers  who  are  not  provided 
with  a  variometer,  but  the  results  will 
be  about  the  same  in  either  case.  If  it  is 
desired,  the  tube  (T2)  can  be  made  non- 
regenerative  with  the  variometer  or  tuned 
impedance  omitted  altogether,  and  while 
the  amplification  will  not  be  as  great 
this  way,  yet  it  will  be  considerably 
greater  than  with  a  crystal  detector. 
An  audio  frequency  transformer  (AT-1) 
with  a  ratio  of  from  5-1  to  6-1,  is  used 
for  coupling  the  detector  stage  output 
with  the  amplifier  input.  This  is  of  the 
usual  iron  core  type  and  needs  little 
further  comment.  Both  the  primary 
and  secondaries  of  the  transformers  are 
bypassed  by  the  fixed  condensers  (Kl) 
and  (K2).  These  will  probably  work 
out  at  0.002  mf,  but  in  some  cases  the 
transformer  characteristics  are  such  that 
they  can  be  eliminated  altogether.  The 
usual  grid  condenser  (GC)  of  0.00025  mf 
is  used  in  the  grid  circuit  of  the  detector 
tube,  and  a  one  megohm  grid  leak  (GL) 
is  connected  across  the  grid  condenser. 
As  the  detector  tube  is  not  in  the  aerial 
circuit,  a  higher  grid  leak  value  can  be 
used  than  when  the  detector  is  in  the 
forward  position  and  there  will  be  no 
trouble  with  oscillations  and  radiation. 
From  45  to  90  volts  of  "B"  battery- 
can  be  used  on  the  amplifier  tube  (Tl), 
but  the  plate  voltage  of  the  detector  tube 
depends  upon  the  type  of  tube  employed 
at  (T2).  If  a  soft  detector  tube  of  the 
UV-200  type  is  used  for  (T2)  we  cannot 
have  more  than  22.5  volts  at  this  point, 
and  as  a  rule  it  is  not  advisable  to  have 
more  than  45  volts  with  any  detector 
(T2)  as  higher  voltages  give  greater 
tendency'  toward  squealing  and  oscilla- 
tions. To  provide  for  the  use  of  two 
plate  voltages  for  the  detector  and  ampli- 
fier, a  detector  tap  is  shown  at  (DB). 


life 

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^         IV   (0  ft  S  .^ 


rml 


46         RADIO  AGE  for  March,  1925 


What  the  Broadcasters  are  Doing 


"Mrs.  Schlagenhauer"  Steps  Up 


dArt  Linick,  Comedian  of 

KYW,  Proves  a  Real 

Dark  Horse 

ONCE  more  a  comedian  has  come  to 
the  front  to  prove  that  the  radio 
audience  has  a  highly  developed 
funny-bone.  None  other  than  Art 
Linick,  Mrs.  Schlagenhauer  "himself," 
lumped  a  series  of  hurdles  from  Decem- 
ber 16  to  January  IS  to  finish  in  first 
place  for  the  month. 

A  Few  Minutes  with  "Mrs.  Schlag- 
enhauer" 

By  E.  E.  Mattson,  KYW 
Radio  has  known  "Mrs.  Schlagen- 
hauer" for  a  long  time,  and  fans  have 
listened  while  the  radio  "aired"  her 
domestic  griefs  and  family  quarrels,  but 
probably  there  are  not  so  many  who 
know  the  originator  of  "Mrs.  Schlagen- 
hauer." He  is  probably  the  best  recog- 
nized as  a  "Jack-of-all-trades."  His 
earlier  vocations  embrace  anything  from 
giving  voice  to  the  German  dialect  to 
the  peddling  of  real  estate,  and  that's  a 
"lot."  Someone  once  said  that  selling 
■"lots"  is  the  best  way  of  doing  someone 
"dirt."  Therefore,  Art  admits  that  if 
you  can't  find  his  picture  in  the  Rogues' 
Gallery  of  the  Police  Department,  or  in 
the  Hall  of  Fame,  you  ought  to  be  able 
to  find  it  somewhere  in  the  public  press. 
On  the  Battle  Front 

RECENTLY,  when  making  an  un- 
announced call  on  our  hero,  he  was 
found  all  dolled  up  in  war  paint.  He 
had  a  regular  army  coat  on,  and  even  a 
flashy  regulation  hat,  and  his  salutation 
was — (with  a  proper  salute) — "Mrs. 
SchlagenhauerattheBattleof  Bolsheviki." 
Mrs.  Schlagenhauer  must  have  thought 
she  was  in  her  own  kitchen  at  home. 

Without  going  back  into  the  annals  of 
history  too  far  and  nosing  too  deeply 
into  his  private  life,  we  will  start  with 
his  advent  into  the  radio  world.  It's 
more  than  a  year  now  that  Art  came  to 
Westinghouse  station  KYW.  Since  then 
his  activities  as  the  radio  comedian  of 
KYW  have  made  him  a  well-known  ether 
entertainer. 

Radio  is  different;  a  comedian  in 
■vaudeville  enjoys  the  privilege  of  facial 
expression  and  pantomime  to  assist  in 
making  his  sketch  a  success,  but  on  the 
radio  this  is  a  lost  art.     One  must  voice 


By  Harry  Aldyne 


Here's  a  recent  picture  of  Art,  himself, 
without  the  "Mrs.  Schlagenhauer"  rai- 
ment. If  radio  fans  could  only  see  him 
perform,  they'd  appreciate  his  talent  all 
the  more — and  that's  saying  a  lot! 


POPULARITY  CONTEST  COUPON 

Harry  Aldyne,  Contest  Editor 

RADIO  AGE,  500  N.  Dearborn  St.,  Chicago. 

I  wish  to  cast  my  vote  for: 

Name  of  favorite 

Classification- - 

Station. Date  Heard — 

Name  [optional] — 

Address  [optional! 


his  expressions  and 
convey  the  interpre- 
tation of  his  comedy 
act  to  the  listener-in. 
In  this,  Art  surely 
has  succeeded.  The 
Dutch  vernacular, 
of  which  he  is  a 
master,  has  made 
"Mrs.  Schlagen- 
hauer" a  real  radio 
comedy.  There  are 
others,  too,  which 
Art  Linick  has  intro- 
duced. "I  Belong  to 
a  Lodge"  and  "Laugh 

It  Off"  have  come  into  prominence. 
You  have  heard  "No  Foolin',"  "The 
Wedding  Anniversary,"  "How  I  Love 
That  Girl,"  and  many  others  that  have 
been  made  famous  by  Art,  in  a  way  that 
only  he  can  do  it. 

There  are  times,  however,  that  the 
radio  entertainer  does  hear  applause. 
On  October  11,  1924,  when  the  first 
"Radio  Picnic"  was  held  at  the  Grant 
Park  Stadium  of  Chicago,  Art  Linick 
was   given   the   microphone,   and   stayed 

.     there     two     hours 

and    forty-five 
minutes.  Loud 

speakers  had  been 
installed  around 
the  field  so  that 
the  forty  or  fifty 
thousand  people 
attending  could 
distinctly  hear  the 
speaker,  although 
the  talk  was  giv- 
en in  natural  voice. 
This  picnic  was 


MRS-  schlagenhauer  herself 


CLeads   In  Popularity- 
Contest  for  the 
Month 

a  novel  affair;  all  the  local  radio  stations 
were  represented  and  an  interested  audi- 
ence was  there.  There  were  prominent 
members  of  society  and  the  business  world, 
as  well  as  the  lesser  known.  During  the 
time  Art  was  at  the  microphone,  he  kept 
his  audience  at  the  point  of  ecstasy.  His 
was  the  pleasure  of  possibly  being  the  first 
radio  entertainer  to  actually  broadcast 
to  an  audience  which  he  could  see  as  well 
as  hear,  for  the  cheers  were  lusty  and  the 
applause  boisterous.  It  is  a  treat  to 
entertain  a  visible  audience  now  and 
then;  it  is  wonderful  to  be  able  to  feel 
and  hear  their  appreciation. 

Mr.  Linick  finds  other  occupation 
besides  appearing  on  RADIO  AGE's 
monthly  programs  and  other  KYW 
entertainments.  To  be  sure  that  time  does 
not  hang  too  heavily  on  his  hands,  he 
makes  phonograph  records  for  five  com- 
panies; he  appears  personally  in  the  lead- 
ing motion  picture  houses  of  the  middle 
West,  characterizing  "Mrs.  Schlagen- 
hauer" and  his  other 
song  and  monologue 
hits. 

For  six  years  he 
wrote  material  for 
vaudeville.  His  were 
comedy  skits  and 
sketches.  His  name 
is  also  associated  with 
those  of  other  show 
producers.  Mr. 
Linick  produced  two 
musical  shows  which 
played  in  America 
as  well  as  England. 
(Turn  to  page  72) 


THE  WINNER  FOR  JANUARY 

Art  Linick Entertainer  ...KYW,  Chicago 

WINNERS  OF  PRECEDING  MONTHS 

July _ ..Duncan  Sisters,  KYW 

August Bill    Hay,    KFKY 

September Karl   Bonawitz,    WIP 

October H.  W.  Arlin,  KDKA 

November Bert     Davis,     WQJ 

December Jack     Nelson,     WJJD 

STANDING  TO  JANUARY  IS 
Name  and  Classification  Where  Heard 

Karl    Bonawitz,    Organist WIP,    Philadelphia 

H.  W.   Arlin,  Announcer KDKA,  Pittsburgh 

Bill     Hay,     Announcer KFKX,     Hastings 

Bert    Davis,    Entertainer WQJ,    Chicago 

Art     Linick,     Entertainer KYW,     Chicago 

Harry   M.   Snodgrass,   Entertainer 

WOS,  Jefferson  City 

Duncan    Sisters,    Entertainers -.KYW,    Chicago 

Jack  Nelson,   Announcer WJJD,   Mooseheart 

Lambdin    Kay,    Announcer WSB,    Atlanta 

John  S.  Dagget,  Announcer KHJ,  Los  Angeles 

Ford  and   Glenn,   Entertainers WLS,   Chicago 

J.  Remington  Welsch,  Organist KYW,  Chicago 

E.    L.    Tyson,    Announcer - WWJ,    Detroit 

Hired  Hand,  Announcer WBAP,  Fort  Worth 

Fred  Smith,  Announcer WLW,  Cincinnati 

Jerry  Sullivan,   Announcer-Entertainer 

„.,„„.„  .  WQJ.  Chicago 

Nick  B.  Harris,  Entertainer KFI,  Los  Angeles 

Edward  H.  Smith,  Director-Player 

WGY,  Schenectady 

Wendell  Hall,  Entertainer  WDAF,  Kansas  City 

Howard   Milholland,    Announcer— .KGO,   Oakland 

"Sen"    Kaney.    Announcer  KYW,    Chicago 

Scottish  Rite  Orchestra,  Orchestra....KGO,  Oakland 


RADIO  AGE  for  March,  1925 

The  Original 
Czar  of  Jazz 


A  Sketch  of ' '  The  Man  Who 
Can  Make  the  Piano  Talk" 


By  RUSSELL  H.  HOPKINS 


What  the  Boradcasters  are  Doing         47 


If     you     know     anything 
about     jazz,     you've 
Axel  Chris- 
Here's  an 
amiable  pose  of 
him. 


ANYONE  who  knows  anything  at 
all  about  jazz  has  heard  of  Axel 
Christensen.  His  name  is  almost 
synonymous  with  jazz.  He  was  brought 
up  on  jazz.  And  today  he  is  an  acknowl- 
edged national  authority  on  the  synco- 
pation  of  the  piano. 

Axel  has  been  playing  the  pjano  for 
so  long  that  the  beginning  of  his  activ- 
ities cannot  be  recorded  with  any  degree 
of  accuracy.  And  he  was  among  the 
first  to  widen  his  acquaintance  among 
lovers  of  the  popular  brand  of  music 
by    utilizing   radio    broadcasting. 

He  owns  a  string  of  music  schools  in 
Chicago  known  as  the  Christensen 
Schools  of  Popular  Music,  and  between 
personally  instructing  hundreds  of  pupils 
every  day,  he  manages  to  tour  such 
broadcasting  stations  as  WQJ,  KYW 
and   WTAY   with   surprising   regularity. 

A  Versatile  Artist 

CHRISTENSEN'S  unique  trait  is 
that  he  is  not  an  expert  pianist 
alone.  Even  if  he  were,  he  would  still 
be  an  interesting  radio  personality, 
for  the  way  he  makes  the  piano  keys 
"jump"  into  the  microphone  is  little 
short  of  astonishing.  He  has  been 
described  as  one  of  the  very  few  jazz 
pianists  who  can  really  make  a  piano 
talk;  and  making  a  piano  talk  means 
playing  it  in  all  kinds  of  moods — soft 
dreamy  melodies;  lively,  syncopated 
dance  affairs;  and  easy,  nerve-soothing 
selections. 

Christensen  can  do  all  that,  and  as 
a  result  a  piano  in  his  hands  is  like  a 
sculptor's  clay — a  thing  to  be  handled 
at  will  to  express  any  human  emotion 
that  he  desires  to  transfer  into  the 
language   of  the  ivory   keys. 

In  addition  to  his  rapid-fire  playing 
of  piano  selections,  Christensen  is  a 
keen   student   of   monologues.      None   of 


his  programs  is  complete  without  one 
of  his  original  pianologues,  which  he 
tells  in  his  own  way — sometimes  in 
Swedish  dialect,  sometimes  in  German 
— and  others  in  straightforward  "Eddie 
Guest"   style. 

Of  course,  Christensen's  most  famous 
radio  characterizations  are  his  Swedish 
monologues.  Although  his  amiable  coun- 
tenance cannot  be  viewed  by  his  radio 
audience,  his  voice  alone  is  enough  to 
cause  spasms  of  laughter  at  the  receiving 
end.  And  all  of  his  vocal  success  would 
not  be  possible  if  it  were  not  for  the 
fact  that  he  has  a  perfect  radio  voice 
— a    rich    baritone. 

A  National  Figure 

AXEL  has  toured  every  city  of  im- 
portance in  the  country  during 
his  musical  career,  so  he  is  well  known 
wherever  jazz  is  popular.  His  first 
accomplishment  was  the  conversion  of 
Mendelssohn's  Wedding  March  into  a 
jumpy,  rag-time  refrain  that  would 
make  a  splendid  entrance  cue  for  a 
couple  of  end  men  in  an  old-time  min- 
strel show. 

In  fact,  Axel  possesses  a  peculiar 
touch  that  enables  him  to  "jazz  up" 
any  creation  regardless  of  its  time 
or  character.  This  ability  is  known  as 
the  "Christensen  System"  of  piano 
playing. 

He  has  always  had  a  fondness  for 
the  songs  popularized  by  Bert  Williams, 
the  late  Negro  character  singer,  and 
on  several  occasions  Axel  favors  his 
radio  audiences  with  some  old  Williams 
songs,  such  as  "Somebody,"  "Samuel," 
and   "The  Lee  Family." 

Although  Axel  was  among  the  first 
to  adopt  jazz  when  it  swept  the  country 
during  the  world  war,  he  is  really  a 
proponent  of  the  old  "rag-time,"  the 
predecessor  of  jazz.  Rag-time  possesses 
many  of  the  lively  qualities  of  jazz,  so 


Axel  had  no  trouble  in  switching  from 
one  form  of  playing  to  the  other. 

After  about  ten  years  of  obscurity, 
he  suddenly  rose  to  fame  (and  that  was 
about  twenty  years  ago),  and  gained 
the    monicker    of    "Czar    of    Ragtime." 

Now,  when  you  hear  him  announced 
from  a  radio  station,  you  hear  Axel 
introduced  as  "The  Czar  of  Jazz."  And 
that  title  should  be  his  to  have  and  to 
hold;  for  if  anyone  has  a  priority  claim, 
on  the  world  of  jazz,  Axel  Christensen 
is   that    person. 

A  XEL  CHRISTENSEN  is  one  of  the 
-^*-  greatest  proponents  of  radio  broad- 
casting as  the  perfect  means  of  adver- 
tising one's  livelihood.  Although  Axel 
is  not  so  mercenary  as  to  broadcast  for 
the  sake  of  advertising  his  school  alone, 
he  admits  the  publicity  gained  from  radio 
performances  greatly  helps  to  keep  the 
customers  trickling  into  his  offices  every 
day. 

Maybe  it  is  because  Axel  uses  radio  as 
an  advertisement  in  a  "subtle"  way  that 
he  reaps  such  profitable  returns.  You 
see,  he  doesn't  need  to  have  it  announced 
that  he  teaches  piano,  and  where,  and 
for  how  much.  That  is  unnecessary. 
If  his  playing  makes  a  "hit,"  he  avers, 
the  prospective  customers  will  find'  out 
all  about  him  on  their  own  initiative. 

So  Axel  merely  plays  his  best  and  varies 
his  program  wherever  he  appears  before 
the  critical  microphone.  As  a  result  his 
reputation  has  spread  far  and  wide,  and 
if  he  was  well  known  before  the  coming 
of  radio,  he  is  positively  famous  today 
His  long  list  of  students  and  his  endless 
list  of  radio  listeners  and  admirers  are 
the  best  proof  of  his  popularity. 

He  may  next  be  heard  on  a  special 
RADIO  AGE  program  from  KYW, 
Chicago,  beginning  at  midnight,  Satur- 
day, March  7. 


48         RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


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oiiAmerica 


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RADIO   AGE/or  March,  1925 


The  Magazine  of  the  Hour         49 


JPiclc'-ixp^ 

Hook-ups 

c^j^  ottr  ffeaders 

'pHE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  i3 
■^  contributed  by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


WELL,  fellows,  here  we  are  again, 
with  some  new  records  for  us 
to  shoot  at.  Some  of  the  finest 
DX  lists  were  submitted  this  month 
that  the  Editor  has  ever  had  the  privilege 
of  reading.  It  was  a  real  task,  deciding 
who  the  lucky  few  would  be  .to  get 
their     Dial    Twister    buttons. 

After  numerous  plans  had  been  de- 
vised and  countless  schemes  given  trial, 
we  finally  found  a  method  by  which 
the  lucky  people  whose  name  you 
will  see  to  the  right  were  awarded  their 
Dial    Twister    "degree." 

From  the  way  letters  pour  into  this 
department,  the  brotherhood  certainly 
gets  a  lot  of  fun  breaking  records. 
From  all  indications  it  seems  that  the 
Canadian  lads  have  a  slight  edge  on 
all  others  when  it  comes  to  "dragging 
in"  the  real  long  distance  stations, 
and  their  records  have  provided  a  real 
incentive  for  many  of  the  other  readers 
of   these   columns. 

We  want  to  thank  the  fans  who  so 
kindly  submitted  the  fine  contributions 
to  this  department,  and  to  those  of 
you  whose  letters  are  not  published  we 
want  to  say  that  we  wish  this  depart- 
ment were  only  large  enough  to  publish 
every  letter  we  received  during  the 
month  just  passed.  It  is  our  intention 
to  keep  them  on  file  and  to  find  room 
for   them   from    time   to   time. 

Mr.  F.  Day  furnished  us  with  good 
technical  information  regarding  a  new 
type  super-heterodyne.  The  circuit, 
which  you  will  find  described  in  another 
part  of  this  departfnent,  is  the  last 
word  in  selectivity  and  volume.  We 
know  because  we  have  listened  to  it. 
We  also  have  a  very  interesting  account 
of  a  really  good  reflex  circuit  from  Mr. 
Dolan.  This  set  has  proven  to  be  a 
good  one  and  I  am  sure  that  the  reflex 
fans  will  become  very  much  attached 
to  it.  Mr.  DePew  gives  us  a  nice  crisp 
article  on  a  radio  frequency  receiver 
that  he  is  using,  and  from  which  he 
is  getting  mighty  fine  results.  These 
three  circuits  should  give  you  plenty  to 
think  of  during  the  coming  month. 

Before  we  go  to  press  "super-power" 
will  have  become  a  reality  and  we 
anxiously  await  letters  from  our  readers, 
telling  us  just  how  these  stations  are 
coming  in.  No  doubt  some  of  the  fans 
are  going  to  have  considerable  trouble 
separating  the  various  stations.  Not 
that  it  will  be  the  fault  of  the  trans- 
mitters, but  rather  the  fault  of  the 
receiving  set  itself,  particularly  the 
single  circuit  type  of  set,  as  a  circuit 
of  this  type  will  always  to  a  certain 
extent  tune  rather  broad.  Any  of  you 
who  experience  any  trouble  are  invited 
to  avail  yourselves  of  the  services  of 
our  technical  staff,  who  will  advise 
you  so  as  to  tighten  up  the  old  set  and 
get    through. 


HARRY  DOLAN 

Aurora,  111. 


CONTRIBUTORS 

CHAUNCEY  DePEW 
Alpena,  Mich. 

DIAL  TWISTERS 


F.  DAY 

Chicago,  111. 


Name  Address  City 

Mrs.  W.  H.  Fisher 614  Allison  Ave Pittsburgh,  Pa. 

Stanley  H.  Cox Box  No.  7 Fulton,  Kas. 

H.  W.  Webb 51  Second  Ave Little  Falls,  N.  J. 

J.  N.  Bacon Oshkosh,  Wis. 

L.  Sherk__ Peoria,  111. 

Chas.  W.  Lawson. 9812  90th  Ave Edmonton,  Alta.,  Can. 

Turner  H.  McBaine 11  Glenwood  Ave Columbia,  Mo. 

Clifton  M.  Beaty Chino,  Calif. 

J.  Clayton 118  Morrison  Ave Toronto,  Ont.,  Can. 

Elmer  J.  Kenealy 505  E.  68th  St.._ Los  Angeles,  Calif. 

Alfred  La  Cascio,  Jr 187  Strathmore  Rd Brighton,  Mass. 

F.  Timoney 428  Arctic  St Bridgeport,  Conn. 

Hugh  W.  Patterson 516  So.  2nd  St McAlester,  Okla. 

J.  B.  Thompson 1741  New  England  Ave Los  Angeles,  Calif. 

James  Smith 587  Sibley  St Hammond,  Ind. 

John  R.  Dell Box  54     Selkirk,  Ont.,  Can. 

Harry  Dean. Auburn,  Ind. 

Willie  R.  Jones 1233  Reynold  St.. Shreveport,  La. 

Richard  Skidmore Drawer  "D" Upland,  Calif. 

Thomas  J.  Kindel Carlsbad,  New  Mexico 

J.  C.  Dunn 2518  Greenmount  Ave Baltimore,  Md. 

D.  O.  Easton.__ 214  Dalzell  St Shreveport,  La. 

Robert  Zurlinden 1507  Ferndale  Rd.,  N.  W... Canton,  Ohio 

Wilbur  Reinhard _ 30  W.  Fulton  St Columbus,  Ohio 

Tom  Winn._ 4219  Marcy  St Omaha,  Neb. 

A.  Lalonde. 183  Garry  St Winnipeg,  Man.,  Can. 

J.  Homer  McNeely _...5036  Manzall  Ave Kansas  City,  Mo. 

Jerome  Davis 9  Hill  St Binghamton,  N.  Y. 

Henry  F.  Brunken 9663  Burnette  Ave Detroit,  Mich. 

Paul  Di  Marzo 316  15th  St.,  N.  E Washington,  D.  C. 

Willard  Zahalka 509  Hubbard  St... Racine,  Wis. 

Karl  A.  Hutch Atlanta  University Atlanta,  Ga. 

P.  N.  Lyons Box  No.  477 Washington,  III. 

Joseph  Brady 3806  Union  Ave _ Chicago,  111. 

H.  Huehner 25  Lincoln  St .Stoneham,  Mass. 

Raynond  D.  Brown 5953  Augusta  St.. Chicago,  111. 

A.  Deo  Rosiero 256  Bridge  Ave Windsor,  Ont.,  Can. 

Wm.  McPherson Caledonia  Mines   Cape  Breton,  N.  S.,  Can. 

J.  Fedora 1342  19th  St Granite  City,  111. 

Arthur  Juola 302  Melbourne  St Astoria,  Ore. 

Merville,  Chamberlin Gibbons,  Alta.,  Can. 

Robert  R.  Schuster 531  Rice  St Springfield,  Ohio 

C.  J.  Ahern,  Jr Dwight,  111. 

R.  P.  Erlick___ 2120  Monroe  Ave Norwood,  Ohio 

C.  Dawson Ardenode,  Alta.,  Can. 


This  high  power  transmission  is  going 
to  prove  a  new  source  of  delight  to  the 
fan  who  is  looking  for  DX  reception, 
judging  by  the  manner  in  which  some 
of  the  stations  that  have  already  in- 
creased theirs  are  coming  in.  I'll  bet 
that  their  will  be  plenty  long  distance 
Crystal  work  in  the  future. 


From  one  of  our  contributors,  Mr.  F. 
Day,  comes  a  circuit  for  a  new  type  super- 
heterodyne. We  have  seen  the  set  in 
operation  and  can  vouch  for  its  per- 
formance. Those  of  you  fans  who  are 
interested  in  super-heterodynes  will  find 
this   circuit    worthy    of   consideration. 

The  outstanding  features  of  the  set  are: 


50 


RADIO  AGE  for  March,  1925 


The  above  photograh  shows  the  super-het,,  constructed  by  Mr.  Day.  Note  the 
compactness  of  the  set.  Study  the  method  used  of  laying  out  the  sockets.  The  audio 
jrequency  transformers  are  on  the  under  side  of  the  sub-panel. 


1.  DX   reception: 

2.  Ease  of  operation, 

3.  Selectivity; 

4.  Large  amount  of  volume  on  a  loop 
antenna; 

5.  Exceptionally   fine  tone   qualities. 

6.  Ease   of  construction; 

7.  It  is  portable; 

8.  Small  in   size; 

9.  It  is  non-radiating; 

10.   Low    battery    consumption. 

The  circuit  was  designed  by  the  Chief 
Engineer  of  the  U.  S.  Signal  Corps,  Jack- 
son H.  Pressley.  The  design  is  such  that 
there  is  no  possibility  of  radiation  even 
over  slight  distances  of  a  few  yards.  This 
is  made  possible  by  the  simple  method 
employed  to  connect  the  detector-os- 
cillator tube  to  the  loop  antenna. 

The  circuit  is  designed  to  cover  the 
broadcasting  wavelength  band.  A  small 
switch  is  used  to  change  from  the  higher 
to  the  lower  wavelengths. 

The  entire  set  can  be  mounted  on  a 
panel  seven  by  eighteen  inches.  The 
cabinet  can  be  made  large  enough  to 
completely   house    the    "B"    batteries. 

The  wiring  diagram  is  published  on 
this  page  and  by  comparing  it  with  the 
back  panel  view,  the  experimenter  can 
get  an  idea  as  to  how  the  apparatus 
should  be  placed. 

The  following  key,  when  used  in  con- 
nection   with    the    wiring    diagram    will 


enable  the  builder  to  determine  the  loca- 
tion of  the  various  items  used. 

I  and  1A.  Oscillator  coil  Unit. 

2.  Vernier    condenser    .0005    Mfd. 

3.  Vernier    condenser    .0005    Mfd. 

4.  Split  stator  balancing  condenser. 

5  and  5A.  Mica  fixed  condensers 
.00015  Mfd.,  and  grid  leak  mounting. 

6.  Fixed   mica  condenser  .005   Mfd. 

7.  By-pass  condenser  .5   Mfd. 

8  and    8A.    1-2    and    2  meg.  grid  leaks 

9  and  9A.  30  ohm  rheostat. 

10  and  10A.  Intermediate  frequency 
transformers. 

II  and  11A.  Intermediate  frequency 
transformers. 

12  and  12A.  Audio  frequency  trans- 
formers. 

14.  Single  circuit  jack. 

15.  Double    circuit    jack. 

16.  Switch   (for  long  or  short  waves). 

17.  Battery  switch. 

Square  or  round  wire  can  be  used  to 
connect  the  various  instruments  together. 
As  round  wire  is  the  easiest  to  handle  it 
is  the  best  to  use.  The  job  will  look 
just  as  neat  as  if  the  square  wire  were 
used.  Before  wiring,  study  the  back 
panel  photograph  carefully,  and  note 
how  the  wires  are  bent,  so  as  to  avoid 
one   another. 

One  of  the  peculiar  things  about  this 
circuit  is  the  manner  in  which  the  tubes 
are    connected.      The    filaments    of    the 


The  Magazine  of  the  Hour 

first  five  tubes  are  connected  in  series 
instead  of  in  parallel,  as  is  usual.  The 
set  operates  on  a  six  volt  battery  and 
draws  a  little  over  three  quarters  of  an 
ampere  filament  current.  This  is  because 
the-first  five  tubes  are  WDll'sor  WD12's, 
the  last  two  tubes  are  either  201A's  or 
other  six  volt  tubes,  operated  in  parallel 
across  the  battery. 

The  circuit  is  balanced  by  means  of  a 
split  stator  balancing  condenser.  A 
pair  of  headphones  is  connected  in  series 
with  the  45  volt  positive  "B"  battery 
lead  that  runs  to  the  first  tube,  and  then 
with  the  oscillator  dial  set  at  about  40 
degrees,  vary  the  balancing  condenser 
and  the  tuning  condenser  until  no  click 
(or  a  minimum  click)  is  heard  when  the 
tuning  condenser  is  in  tune  with  the 
oscillator  circuit.  This  setting  of  the 
balancing  condenser  will  be  found  to 
be  very  near  its  maximum  capacity. 
When  the  proper  position  of  the  plates 
has  been  determined  the  condenser  can 
be  locked  in  position  by  means  of  a  small 
set  screw,  provided  for  that  purpose. 

The  operation  of  the  set  is  very  simple. 
Simply  set  the  condenser  (2)  to  the  proper 
setting  for  the  correct  wavelength,  and 
then  set  the  condenser  (3)  to  the  cor- 
responding oscillator  frequency,  adjust 
the  loop  to  the  point  at  which  the  signals 
come  in  loudest,  and  regulate  the  volume 
by  means  of  the  rheostat  .  controlling 
the  audio  amplifiers. 

F.  Day  of  4456  No.  Racine  Ave.,  Chi- 
cago, 111.,  was  kind  enough  to  furnish  us 
with  the  above  data  on  this  circuit. 
Mr.  Day  is  a  radio  experimenter  of  note, 
and  we  are  sure  that  any  circuit  that  he 
approves  of  must  have  given  exception- 
ally fine  results. 

Harry  Dolan  of  Aurora,  111.,  one  of 
our  contributors,  tells  us  of  the  wonderful 
results  he  is  having  with  a  reflex  set  of 
his  own  construction.  It  must  be  a 
"whiz  bang,"  so  we  are  going  to  pass  it 
along  to  the  fans. 
RADIO   AGE: 

As  I  am  a  continual  reader  of  the 
"Pick-ups  and  Hook-ups"  section  of 
RADIO  AGE,  and  a  confirmed  be- 
liever in  the  reflex  type  of  set,  I  have 
noticed  with  particular  interest  the 
hookups  published  in  these  columns, 
for  reflex  circuits.       (Turn  to  page  52) 


Wiring  diagram  of  the  super-heterodyne  perfected  by  the  Army  engineers,  for  the  reception  of  signals  transmitted  to  airplanes. 
Note  the  radical  departure  from  the  usual  form  of  an  oscillator  coil.      The  intermediate  transformers  should  be  tuned  to  4500  cycles. 


RADIO  AGE  for  March,  1925 


The  Magazine  of  tlie  Hour 


Tin 

i  ■  -in 

LA  \jJ 

I 

IJ 

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30 


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81 


COMPLETE  PARTS  FOR  8-TUBE 

SUPER-HETERODYNE 


2  23-Plate  Duplex  or  Laboratory 

Type  Low  Loss  Condensers 

3  Remler  or  Columbia  Interme- 

diate Frequency  Transform- 
ers 

1  Remler  or  Columbia  Tuned  Cir- 
cuit Transformer 

1  Special  Oscillator  Coupler 

1  Midget  Condenser 
8  Bakelite  Sockets 

2  Thordarson  or  Columbia  A.  F. 

Transformers 

1  Connecticut  Filament  Switch 

2  Bakelite  &-ohm  Rheostats 
2  Bakelite  30-ohm  Rheostats 

1  Bakelite     Potentiometer,     400 

ohms 
1  Carter  Double  Circuit  Jack 
1  Dubilier  1  mid.  Condenser 


1  .006  Mica  Condenser 

1  .0005  Mica   Condenser  and  2 

megohm  Grid  Leak 
3  .0025  Mica  Condensers 
10  Binding  Posts 
1  .00025  Mica  Condenser 
1  Bakelite    Terminal    Strip    for 

Binding  Posts 
1  Multieord  Cable  for  connecting 

1  7s30x'i's  Drilled  Bakelite  Panel 

1  Baseboard 

35  ft.  Hook-up  Wire 


552" 


Complete  wiring  diagrams,  base 
board  layout,  blue-prints  and 
instructions. 


COMPLETE  PARTS  FOR 

ACME    1-Tube     r<i  r    o  r 
REFLEX blb.OD 

ACME  4-Tube        MQ   8£ 
REFLEX 3><M»0;i 

with  Genuine  Acme  parts  as 
specified,  drilled  bakelite  panel 
and  full  wiring  diagram. 


COMPLETE    PARTS    FOR 
2-TUBE    HARKNESS    SET 

including  Licensed  Hark- 
ness  Coils,  Drilled  Panel 
and  wiring  diagram.  Easyto 
build.  Wonderful 
results 


$17.95 


COMPLETE   PARTS    FOR 
REINARTZ 

1-J£<se.Rein:.  $10.45 

3-Tube       Rein-    CI  7   EC 
artz  Set ***  ■«"» 


COMPLETE  PARTS  FOR  5-TUBE 

NEUTRODYNE  RECEIVING  SET 

Genuine  Hazeltine  Licensed  Fadav  or 
other  Genuine  Licensed  Parts 


1  7s24sI^i  Drilled  Panel 

2  Thordarson  or  Columbia 

Audio  Transformers 

3  4-in.  Bakelite  Dials 
2  Precision  Jacks 

1  Bakelite  Rheostat,  30-ohm 
1  Bakelite  Rheostat.  6-ohm 
1  Bakelite  Binding  Post  Strip 
7  Marked  Binding  Posts 
1  Grid  Leak  and  Condenser 
5  Bakelite  Sockets 


1  .001  Condenser 

1  .006  Mica  Condenser 

35  feet  Hook-up  Wire 

1  Kit  consisting  of  3H.azeltlne 

Licensed    Neu-« 

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2     Neutrodons 
1  Baseboard 
3  Bezels 
Complete  blue  -  prints  and 

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imazeitine 

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COMPLETE   PARTS   FOR   5-TUBE 

IMPROVED    COCKADAY     RECEIVING    SET 

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Easy  to  Build  Your  Own  Radio  Set 

All  complete  parts  for  sets  on  this  page  consist  of 
standard  advertised  guaranteed  parts  and 
include  drilled  bakelite  panels  and  wiring 
diagrams  for  easy  set  construction. 
Everything  guaranteed  on  money-back  basis.  All 
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This  service  is  free  to  our  customers. 


Genuine  Radio  Corporation  Tubes  UV201-A, 

UV199,  WD12  or  WD11 $  3.5S 

Home  Charger,  6-volt 12.95 

Soldering  Iron 95 

Solderall  Tube 19 

Approved  Lightning  Arrester 35 

Cockaday  Colls 1.59 

Balancing  Condensers,  per  pr 59 

Harkness  Colls,  per  set 1.95 

Hydrometer.  Best  Quality 44 

Battery  Meters,  0  to  50  volts 89 

Mafinavox,  M4,  Loud  Speaker 20.95 

Baldwin  Loud  Speaker 19.95 

_Brandes  Table  Talker 8.45 

■  Atlas  Loud  Speaker 21.95 

!  Multiple  Four  Phone  Plug 89 

Two  Phone  Plug 24 

Complete  Antenna  Outfit,  including  Light- 
ning Arrester 2.59 

Bakelite  Moulded  Variometer 3-25 


COMPLETE  PARTS   FOR    3-TUBE 

COCKADAY  RECEIVING  SET 


1  Cockaday  Coil 

2  23-Plate  Hy-Grade  Cond. 

1  Bakelite  Rheostat,  6-ohm 

2  Bakelite  Rheostat,  30-ohm 

3  Bakelite  Sockets 

1  high    ratio     Columbia    or 
Thordarson  Transformer 
t  Single  Circuit  Jack 

1  low  ratio  Columbia  or  Thor- 

darson Transformer 

2  Double  Circuit  Jacks 
2  3-in.  Bakelite  Dials 

1  Grid  Leak  and  Mica  Cond. 


7  Switch  Points.    2  Stops. 

1  Bakelite  Binding  Post  Strip 

7  Binding  Posts 

1  7x21  x'.-ti  in.   Drilled  Bake- 
lite Panel  ft  Jt  a  r  £ 

3  Bezels  >1  Odd 

1  Baseboard    ▼  ■ 

1  Switch  Lever 

24-ft.  Hoop-up 
Wire 

Complete  blue-prints  and  wir- 
ing diagrams,       ci n  in 

l-Tube  Set  3J.U.J.U 


Drilled  Bs 

18! 


Low  Loss  Condensers: 

11 -plate 51.3S 

23-p!ate 2.0S 

43-plate 2.85 

Bakelite  Rheostats: 

6-ohm S0-35 

30-ohm 38 

Amperites: 

For  all  tubes. . .  $0.94 

Bakelite  Dials: 

2-inch $0.26 

3-  Inch 35 

4-inch 48 

Composition  Dials: 

2-lnch $0.13 

3-inch 17 

4-inch 29 


Accuratune  Dials. $3.14 

Audio  Transformers 

Thordarson: 

3K  to  1 S3.2S 

6  to  1 3.65 

Acme 3.95 

Columbia: 

3(jto  1 $3.79 

6  to  1 3.89 

American  Bell: 

3!^  to  1 $2.45 

6  to  1 2.79 

Randolph  Special: 

3VSto  1 $1.89 

6  to  1 2.16 

Randolph  Special 
Headphones $2.24 


RANDOLPH    RADIO   CORPORATION 

159  North  Union  Ave.  Dept.  422  Chicago,  Illinois 


52         RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


Circuit  contributed  by  Harry  Dolan.  A  reflex  circuit  that  has  given  exceptionally  good 
results.  The  transformer  at  lower  right  hand  side  of  drawing  is  an  iron  core  A.  F. 
transformer. 


I  believe  I  can  safely  say  that  I  have 
tried  practically  all  the  different 
methods  of  making  tubes  do  double 
duty.  And  the  only  one  that  has 
proven  to  be  a  real  success  is  the  one 
that  I  am  going  to  describe. 

Using  only  one  tube,  I  am  able  to 
receive  all  the  Chicago  stations,  (a 
distance  of  about  thirty-five  miles) 
with  sufficient  volume,  on  a  loud 
speaker,  to  be  heard  all  over  the  lower 
floor  of  my  house.  The  set  is  remark- 
ably free  from  distortion,  and  its  tone 
qualities  cannot  be  surpassed.  But 
enough  for  praise;  let  the  skeptical 
ones  build  it  and  see  for  themselves. 

By  looking  at  the  wiring  diagram, 
you  will  notice  that  the  radio  fre- 
quency transformers  are  of  the  tuned 
type.  As  these  can  be  purchased  from 
any  radio  store  for  a  reasonable  sum, 
I  would  suggest  that  the  experimenter 
do   so.      Both   the   condensers   have   a 


capacity  of  .0005,  and  are  preferably 
of  the  straight  line  type.  It  is  advis- 
able to  have  a  vernier  attachment  on 
them. 

The  audio  transformer  should  have 
a  ratio  of  about  four  to  one.  Increas- 
ing the  ratio  of  this  transformer  will 
increase  the  signal  strength,  but  then 
the  set  has  a  tendency  to  distort. 

The  crystal  detector  should  be  of 
the  fixed  type,  and  be  sure  that  it  is  a 
good  one,  as  many  times  the  bad  re- 
sults obtained  with  a  reflex  set  can 
be  attributed  to  a  poor  crystal. 

The  set  can  conveniently  be  mounted 
behind  a  panel  eight  by  eight  inches, 
and  the  whole  (including  "A"  and  "B" 
batteries)  put  in  a  cabinet  sixteen  by 
eight  by  eight  inches.  As  can  be  seen 
by  the  above  dimensions,  the  complete 
receiver  makes  an  ideal  portable. 

It  is  very  selective.  Thus  the  tuning 
will    be   extremely   sharp,   one   or  two 


degrees  on  the  dial  separating  stations. 
Tube  control  is  not  critical,  however, 
and  a  fixed  resistance  can  be  substi- 
tuted for  the  filament  control,  if  the 
builder  so  desires. 

I  used  this  receiver  entirely  last 
Summer,  and  the  East  Coast  was 
heard   regularly. 

Amongst  the  stations  that  I  heard 
during  the  last  week,  while  the  power- 
ful Chicago  stations  were  in  operation, 
are  KDKA,  WGY,  WOAW,  KTHS, 
WBAP,  WSB,  KFKX  and  during  the 
silent  period  (Monday  night)  KFI, 
KGO,  KDYQ,  and  KFOA.  With  one 
stage  of  straight  audio,  almost  all  of 
the  above  stations  were  heard  on  the 
loud  speaker. 

Trusting  that  you  will  have  enough 
space,  this  month,  to  publish  the  above 
letter,    I    remain 

Yours  very  truly, 
HARRY  DOLAN,  Aurora,  111. 
Well,  reflex  fans,  we  thought  that  on 
the  strength  of  Mr.  Dolan's  letter,  the 
circuit  described  certainly  was  worthy 
of  consideration.  We  know  that  the  set 
works  very  well  because  we  have  listened 
in  quite  a  few  times  on  receivers  that 
employ    the    same    design. 

The  tuned,  air  core  radio  frequency 
transformers  can  be  wound  by  the 
experimenter  if  he  so  desires.  The  second- 
ary is  wound  on  a  tube  three  inches  in 
diameter,  and  consists  of  66  turns  of 
No.  26  D.  S.  C.  wire.  The  Primary  is 
wound  on  top  of  the  66  turns  and  consists 
of  11  turns  of  the  same  size  wire.  Separ- 
ate the  secondary  from  the  primary  with 
either  empire  cloth  or  waxed  paper. 


We  want  to  call  the  attention  of 
our  readers  to  the  fact  that  numer- 
ous letters  are  received  by  the 
Technical  Department  of  RADIO 
AGE  that  we  cannot  answer,  be- 
cause a  stamped,  self-addressed  en- 
velope does  not  accompany  the  re- 
quest. As  we  make  no  charge  for 
this  service,  we  wish  the  fans  would 
co-operate  with  us  in  this  regard. 


End  your  RadioTroubles  for  30c  in  Stamps 


We  have  laid  aside  a  limited  number  of  back  issues  of  RADIO  AGE  for  your  use 
these  issues.   Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired 
store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 

May,  1922 

— How  to  make  a  simple  Crystal  Set  lor  $6. 
September,  1922 

— How  to  make  a  Regenerative  Set  at  a  low  cost. 
October,  1922 


ated). 


— How  to  make  a  Tube  Unit  for  S23  to  $37. 

— How  to  make  an  Audio  Frequency  Amplifying  Trana- 

former. 

November,  1922 

— Design  of  a  portable  short-wave  radio  wavemeter. 

May,  1923 

— How  to  make  a  portable  Reinartz  set  for  summer  use. 

June,  1923 

—How  to  build  the  new  Kaufman  receiver. 

— What  about  your  antenna? 

December,  1923 

— Building  the  Haynes  Receiver. 

— Combined  Amplifier  and  Loud  Speaker. 

—A  selective  Crystal  Receiver. 

January,  1924 

— Tuning  Out  Interference — Wave  Traps — Eliminators 

—Filters. 

■ — A  Junior  Super-Heterodyne. 

— Push-Pull  Amplifier. 

— Rosenbloom  Circuit. 

March,  1924 

—An  Eight-Tube  Super- Heterodyne. 

— A  simple,  low  loss  tuner. 

—A  Tuned  Radio  Frequency  Amplifier* 

— Simple  Reflex  Set. 

RADIO  AGE,  Inc. 


April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illu: 
— A  Ten-Dollar  Receiver. 
— Anti-Body  Capacity  Hookups. 
— Reflexing  the  Three-Circuit  Tuoer. 
— Index  and  first  two  installments  of  Radio  Age  Data 
Sheets. 


May,  1924 

— Construction  of  a  Simple  Portable  Set. 


June,  1924 

— Important   Factors   in    Constructing   a    Super-Hetero- 
dyne. 
—A  Universal  Amplifier. 
—A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 
— Radio  Age  Data  Sheets. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 
— Operating  Detector  Tube  by  Grid  Bias. 
— A  Three-Tube  Wizard  Circuit. 
— Data  Sheets. 

August,  1924 

—Breaking  Into  Radio  Without  a  Diagram. 

— The  English  4-Element  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

—An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 


.   Below  are  listed  hookups  to  be  found  in 
The  supply  is  getting  low,  so  enrich  your 


September,  1924 

— How  Careful  Mounting  Will  Improve  Reception. 

- — One  Tuning  Control  for  Hair's  Breadth  Selectivity. 

— Four  Pages  of  Real  Blueprints  of  a  New  Baby  Het- 
erodyne and  an  Aperiodic  Variometer  Set. 

—Data  Sheets. 

October,  1924 

— An  Easily  Made  Super-Het. 

— Two  Radio  and  Two  Audio  for  Clear  Tone. 

— A  Simple  Regenerative  Set. 

— The  Ultradyne  for  Real  DX. 

— Real  Blueprints  of  a  3-Tube  Neutrodyne  and  a  Mid- 
get Reflex  Set. 

November,  1924 

— Blueprints  of  a  Single  Tube  Loop  Set  and  a  capacity 
Feedback  Receiver. 

— A  3-Tube  Low  Loss  Regenerator. 

— Mastering  the  3-Circuit  Tuner. 

December,  1924 

- — Blueprints  of  a  New  8- Tube  Super-Heterodyne. 

— How  to  Make  a  Receiver  that  Minimizes  Static. 

— A  Trans-Atlantic  DX  Receiver. 

— How  to  Make  a  Home  Made  Battery  Charger  nod  a 
Loud  Speaker  at  a  Small  Cost. 

January,  1925 

—A  Reflexed  Neutrodyne 

— A  Six  Tube  Super-Het 

— An  Efficient  Portable  Set 

—A  Tuned  Plate  Regenerator 

— Making  a  Station- Finder 

February,  1925 

—A  Sure  Shot  Super-Het 

- — A  Three  Circuit  Reeenerator 

— A  Real.  Low  Losb  Set. 

— Blueprints  of  a  3-tube  Reflex 


500  N.  Dearborn  St.,  Chicago 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour         53 


ijttlCClltC  ^Taulthss  savant  of 

Radio's  invisible  audience 


BAKELITE  combines  proper  - 
ties  which  make  it  unique 
among  insulating  materials. 
It  has  high  insulation  value 
and  great  strength,  resists 
both  heat  and  cold,  and  is 
immune  to  moisture,  oil  and 
fumes.  Bakelite  is  unaffected 
by  time  and  use,  and  its  color 
and  finish  are  permanent. 


Na-ald  Dfal 


Na-ald  Tube 
Socket 


•R.  C.  A.  Tube  Base-     "v 


Radio  has  banished  isolation.  It  has  brought  the  music 
of  opera  and  orchestra,  the  voices  of  statesmen  and 
teachers  into  the  cabin  of  the  woodsman,  the  home  of 
the  farmer  and  to  people  everywhere. 

Bakelite  is  playing  a  vital  part  in  this  universal  radio 
reception.  It  is  used  by  over  ninety-five  per  cent  of 
the  manufacturers  of  radio  sets  and  parts,  for  they 
know  that  Bakelite  insulation  can  always  be  depended 
upon  to  give  superior  results  in  service,  in  any  climate 
and  at  any  time  of  year. 

Some  of  the  many  radio  applications  of  Bakelite  are 
shown  in  the  adjoining  column.  When  buying  a  radio 
set  or  part  make  sure  it  is  Bakelite  insulated,  for  this 
is  a  definite  indication  of  quality. 

Write  Jot  Booklet  H 
BAKELITE    CORPORATION 

247  Park  Avenue,  New  York,  N.  Y. 
Chicago  Office:  636  West  2 2d  Street 


Baled 

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mark  and  can  be 

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factured  by  the 

Baled 

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whicl 

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Icocc. 

THE  MATERIAL  OF  A  THOUSAND  USES 
Tested  and  Approved  by  RADIO  AGE     * 


[5  the  registered  trade 
mark  for  the  phenol 

factured  under  pat- 
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■  Bike  1 1  re  CorporanOC 

3527-B 


54         RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


MEMBER 


tf 


f :-'.,: :- 


Radio  Music 
for  the  Critical 

Music  lovers  find  an  especial  delight  in 
Rauland'Lyric.  Used  in  all  audio  stages 
of  a  radio  receiver,  it  reproduces  with 
fidelity  those  elusive  refinements  of  tone 
quality  which,  to  the  trained  ear,  mean 
artistic  excellence. 

Rauland-Lyric  is  a  laboratory-grade 
audio  transformer  designed  especially 
for  music  lovers.  The  price  is  nine  dol- 
lars. Descriptive  circular  with  ampli- 
fication curve  will  be  mailed  on  request. 
All- American  Radio  Corporation,  2 '.  80 
Coyne  Street,  Chicago. 


'& 


AN 


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K  tV.'AMER/r.. 

PW*,>  TRADE  MARK  1.A/ 

TRANSFORMER 

The  Choice  of  Noted  Music  Critics 


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A  24- Volt  "B"Storase  Battery^  oaitivelygfr-- 
FREE  with  each  purchase  of  a  WORLD  "A" 
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mous for  its  guaranteed  quality  and  service.  Backed 
by  years  of  Successful  Manufacture  and  Thousands  of 
Satisfied   Users.  You  save  60%. 

Prices  That  Save  and  Satisfy 

Auto  Batteries  Radio  Batteries 

6- Volt.  11  Plate  912.25 

fi.Vnlr     npht.      ia  ->e         6-Volt,  100  Amps.      12.50 

t»-voit,  13  Plate     14.25        6-Volt.  120  Amps.     14.50 

12- Volt,     7  Plate     17.00        6-Volt,  140  Amps.     16.00 

Shipment  Express  C.  O.  D.  subject  to  examination. 

6  per  cent  discount  for  cash  in  full  with  order. 

2-Yr.  Guarantee  Bond  in  Writing 
With  Each  World  Storage  Battery 

proves  satisfactory  World  performance.  Mall  this  ad  with 
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This  FREE  "B"  Storage  Battery  takes  the  placo  of  dry  cell 
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equipped  with  solid  rubber  case — and  Insurance  against  acid 
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MICA  CONDENSER 

Patent  Fending 

insure  high  efficiency  and  the 
Build-Up  feature  enables 
the  operator  to  obtain  any 
definite  capacity  from  .0005 
to  .006  by  simply  adding 
extra  plates  of  copper  and 
mica  to  the  Build-Up  base. 

Each  alternate  copper  and  mica  plate  has  a 
capacity  of  approximately  .0002  Mfd. 

Build-Up  Mica   Condensers  of   the  following 
capacities,  each  assembled  complete  in  carton, 
at  the  following  prices: 
.00025  Mfd.... Xlst  price  50c 


50c 
55c 
60c 
65c 
70c 
75c 

Extra  envelope  containing  20  copper  and 
mica  plates,  or  sufficient  to  build  up  a  con- 
denser from  .00025  to  .006,  list  price  25c. 

Table  showing  required  number  of  plates 
needed  for  any  capacity  is  furnished  with 
each  condenser. 

Ask  your  dealer — or  order  direct 

CHAS.  SCHINDLER 

1404  W.  Delaware  Ave.,  Toledo,  Ohio 


CRESCENT  LAV1TE  RESISTANCES 

Absolutely  non-inductiva 


Special  resistances  to  order,  52.50.  When  bette 

are  made  they  bear  the  Crescent  label 

CRESCENT  RADIO  SUPPLY  CO. 

9  Librty  Street  Jamaica.  N.  Y. 


*     Tested  and  Approved  by  RADIO  AGE     * 


Wilson  J.  Wetherbee 


Claiborne  Foster 


RADIO  AGE  for  March,  1925 

A  Day  Out-of-Doors 
withKYW 

A  DAY  or  two  out  of  the  studio  might 
reveal  some  of  the  activities  of  a  radio 
man  that  otherwise  are  not  credited  to 
him.  Wilson  J. 
Wetherbee,  direct- 
or of  Westinghouse 
station  KYW  has 
had  much  outside 
work  to  do. 

Recently  Mr. 
Wetherbee,  with 
Chief  of  Police 
Morgan  Collins, 
Alderman  J.  M. 
Arvey  and  mem- 
bers of  the  mayor's  radio  commission 
made  tests  of  the  use  of  radio  in  police 
cars.  Detective  Chief  William  Schoe- 
maker,  Capt.  John  Stege,  Deputy  Sup- 
erintendent Matthew  Zimmer  and  Mr. 
Wetherbee  con- 
ducted this  test, 
which  was  declared 
to  be  successful. 

The  plan  is  to 
install  radio  sets 
in  each  police  car 
for  the  purpose  of 
picking  up  radio 
orders  over  KYW, 
the  sets  to  be  lock- 
ed on  the  KYW 
meter  wavelength 
to  insure  the  reception  of  all  calls.  These 
special  bulletins  will  be  sent  out  direct 
from  police  headquarters  and  KYW  will 
stand  by  at  all  times  to  broadcast  these 
emergency  calls.  "Stand  by  for  police 
bulletin"  will  be  the  opening  announce- 
ment and  the  signal  for  the  occupants  of 
the  car  to  be  ready  for  orders. 

BUT  all  outside  moments  are  not  al- 
ways work.  A  week  end  visit  to 
Grasmere  Farm,  the  Eugene  V.  Byfield 
country  home, 
provides  a  lot  of 
fun,  especially 
when  a  pleasant 
crew  gets  together. 
There  were  Mr. 
Byfield,  Miss 
Claiborne  Foster 
and  Allen  Dine- 
hart  of  the  Apple- 

'  -         '   SalV^     Co™Pany, 

andMr.  and  Mrs. 
Wetherbee,  making  up  a  recent  party. 

It  was  on  this  occasion  that  a  real 
radio  feature  was  arranged.  Miss  Foster 
and  Mr.  Dinehart  were  invited  to  visit 
the  KYW  studio 
each  Friday  even- 
ing to  put  on  a 
sketch  written  by 
some  radio  fan. 
The  scheme  was 
inaugurated  and 
comedy  skits  were 
received  in  great 
numbers,  the  best 
being  picked  for 
broadcast  in  g. 
The  idea  has  met 

with     unforeseen     popularity,    and    will 
be  carried   out   all   of    this    season. 


The  Magazine  oj  the  Hour        55 


Allan  Dinehart 


NOW 

MODEL  L-2 


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J!ll!]l!llllllllllllllllllll!lini!l!l!ll|l|llllllll!l!lin!i]lllI!:HIIIIIII!l!ll!llllllll]li!!i!llllll[|l!llll!llllllll!!lllD 


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Built  to  Your  Order 

This  is  a  genuine  ULTRADYNE  built  of  parts  endorsed  by 
R.  E.  Laeault,  A.  M.I.R.E.,  Inventor,  and  constructed 
according  to  his  specifications. 

We  guarantee  this  set  to  arrive  in  your  home  in  absolutely 
perfect  condition. 

Ultradyne  Kit 

Carrying  the  last  improvements  of  R.  E.  Laeault,  whose 
personal  monogram  seal  is  on  each  Ultraformer.  Kit  con- 
tains 1  Low  Loss  Tuning  Coil,  1  Low  Loss  Oscillator  Coil, 
1  Type  A  Ultraformer,  3  Type  B  Ultraformers,  4  Matched 
Fixed  Condensers,  1  Low  Loss  180  degree  Coupler. 


150 
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For  those  desirous  of  transforming  their  old  Ultradyne  to  the  improved 
model  L-2,  we  have  arranged  a  special  list  containing  everything  needed. 


One  complete  diagram        -    -    -    -    -__  $0.50 
Bakelite   Panel    (Drffled-Engraved)     -       7.50 
Eight  Amperite  Automatic  filament  con- 
trols       ---- 8.80 

Two  2  in.  Accuratune  Dials   -    -    -    -      1.50 


One  Hammarlund  Condenser  (0005)     -     $5.00 
One  Low  Loss  Oscillator  Coil      -    -     -  1 
One  Low  Loss  Tuning  Coil     -    -    .-    -  j 
One  Low  Loss  ISO  degree  Coupler       -    J 
Two  Stripped  Binding  Posts    -    -     -     - 


9.00 


45 


These  parts  will  be  sent  you  separately  at  the  prices  listed  or  we  will  send 

you  the  kit  complete  for  $29.50. 

The  famous  ULTRA-VERNIER  Tuning  Control $2.50 

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*     Tested  and  Approved  by  RADIO  AGE     *' 


56         RADIO   AGE  for  March,  1925 


The  Magazine  of  the  Hour 


Circuit 


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GET  MORE  VOLUME— GREATER  DISTANCE 
KNIFE-LIFE   SELECTIVITY 


The  Henninger  Aero  Coil  is  the  only 
tuning  inductance  and  is  the  only 
air  core  R.F.  transformer  which 
eliminates  all  resistances  and  conse- 
quent losses  which  broaden  tuning, 
decrease  volume  and  limit  distance 
range.  These  coils  will  give  you  a 
great  deal  more  volume,  greater  in- 
crease your  distance  range  and  give 
you  such  knife-like  selectivity  that 


you  can  tune  through  the  most  diffi- 
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else  like  the  Henninger  Aero  Coil. 
No  inductance  system  is  so  efficient. 
Build  a  tuned  R.F.  receiver  using 
this  wonder  inductance  system — or 
use  a  single  Aero-Coil  in  place  of  the 
tuning  inductance  in  your  present 
set.  $3.50  each  or  $10.50  the  set  of 
three  with  all  fittings. 


Write  for  free  illustrated  circular — "The  Prevention  of  Radio-Frequency  Losses."     Show  how 
to  build  Henninger  Aero-Dyne  and  how  to  improve  any  kind  of  set  by  using  a  single  aero  coil. 

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MAKE  YOUR  RECEIVING 
SET  SELECTIVE 


The  Benson  Wave  Filter  eliminates  an- 
noying interferences.  It  is  of  the  induc- 
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Mounted  in  a  beautiful  leather  covered 
cabinet  with  an  engraved  bakelite  panel. 

PRICE  $8.75 


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VOLUME,    CLARITY,  BEAUTY 

14  inch  Pyralin  Bell.        Aluminum  Sound  Column 

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Send  for  dealers  discount. 


Buy  Your  1925  ANNUAL  Now!    See  Page  80! 


RADIO   AGE  for  March,  1925 


The  Magazine  of  the  Hour 


57 


The  Howard 
Five  Tube  Neutrodyne 

The  most  unusual  set  on 
the  market.  Beautifully 
finished  walnut  case.  Coast 
to  coast  range.  Perfect 
selectivity.  Also  made  in 
Console  type.  Designed 
and  perfected  according  to 
the  Howard  standard — and 
that  says  more  than  any 
superlatives. 

Convince  yourself  by  seeing  and, 
hearing  the  Howard  demonstrated. 
A  ny  Howard  dealer  will  be  pleased 
to  give  you  a  demonstration. 

Howard  Manufacturing  Company 

451-469  East  Ohio  St.  Chicago 


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MILLIONS  are  enjoying  music 
and  entertainment  reproduced  in 
clear,  mellow  tones,  characteristic 
of   TOWER'S     Scientifics. 


Two  Towers 


As  the  Eiffel  Tower  stands  as  a  monument  to  skilled 
engineering  construction  so  TOWER'S  Scientific  phones 
stand  as  a  monument  to  supreme  radio  achievement. 
5  Each  phone  is  carefully  tested  and  approved  before  it 
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with  a  positive  uniformity  of  volume. 
5  Lightest  of  all  in  weight  (only  8'<  oi.)  they  do  not  catch 
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If  your  dealer  cannot  supply  you,  order  direct, 
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The  Eiffel  Tower  built  in  1887-89  on  the 
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The  Wforlds  Greatest  Headset  Value 


58         RADIO  AGE  for  March,  1925 


i  lis  Easy  io  Build  i 

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g       or  any  other  5   tube  tuned  radio  frequency  receive*1 

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Ion  the  market,  reg-ardless  of  price.  Even  those  stations 
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Kit    consists    of    3    Masterpiece 

I  Tuned  Radio  Frequency  Units 
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.123  W.  Madison  St.  Chicago 


*     Tested  and  Approved  by  RADIO  AGE     * 


The  Magazine  of  the  Hour 

A  Permanent  Seven-Tube 
Super-Heterodyne 

{Continued  from  page  15) 
terminals  7    and    8    would   be  the  fixed! 
condenser    supplied    with    the    charged 
filter  transformer. 

After  the  set  has  been  completed,  the 
batteries  may  be  connected  to  it,  90  volts 
being  used  for  the  B-battery  and  three 
dry  cells  for  the  A-Battery  if  199  tubes 
are  used.  A  storage  battery  will  be 
required  if  201-A  tubes  are  used.  A 
4}4  volt  C- Battery  will  be  required  on 
the  audio  amplifier  and  a  1J^  to  4J^S 
battery  on  the  radio  frequency  ampli- 
fier. 

Getting  Started 

rT,HE  right  hand  tube  should  be  in- 
-*-  serted  in  its  socket  and  the  phone 
plug  inserted  in  the  jack.  If  the  grid1 
terminal  of  this  tube  is  touched,  a  click 
should  be  heard.  The  next  two  tubes 
should  now  be  inserted  in  their  sockets 
with  a  5.  megohm  grid  leak  in  the  first 
detector  condenser  clips,  and  a  one 
megohm  grid  leak  in  the  second  de- 
tector clip.  If  the  grid  terminal  of 
the  second  detector  is  touched,  a  squeal; 
or  click  should  be  heard,  which  indi- 
cates that  these  three  tubes  are  function- 
ing properly.  The  two  intermediate 
amplifier  tubes  should  be  inserted  and1 
the  set  should  squeal  as  their  grid  leads 
are  touched,  or  it  may  squeal  continuous- 
ly, which  is  correct.  The  first  detector 
and  oscillator  tube  should  be  inserted1 
and  the  balancing  condenser  turned  to> 
zero. 

If  the  oscillator  condenser  is  rotated1 
with  the  loop  connected  to  the  set,  a 
click  will  be  heard  at  some  point  on  its-, 
scale.  This  point  will  vary  for  different 
settings  of  the  loop  condenser.  A  signal 
may  now  be  tuned  in  by  setting  the- 
loop  condenser  at,  say,  20  degrees,  and1 
rotating  the  oscillator  condenser  through 
a  range  of  ten  degrees  below  the  setting 
of  the  loop  condenser  to  ten  degrees, 
above   its   setting. 

This  process  may  be  carried  out 
throughout  the  entire  wavelength  ranges 
by  resetting  the  loop  condenser  each 
time  at  a  five  degree  higher  value  and 
then  rotating  the  oscillator  condenser.. 
The  set  is  extremely  selective  and  it  is 
very  easy  to  pass  over  stations  unless  it  is 
operated  very  carefully.  Two  points 
will  be  noticed  at  which  a  station  can  be 
heard  on  the  oscillator  dial;  one  on  either 
side  of  the  click  setting.  One  point  will 
be  noticed  on  the  loop  dial.  The  proper 
setting  of  the  oscillator  coupler  rotor  is 
as  far  out  as  possible.  It  should  be- 
adjusted  on  a  very  weak  signal,  and! 
when  set,  it  need  never  be  changed. 

The  Balancing  Condenser 

THE  balancing  condenser  should  be 
used  at  as  low  a  value  as  possible  and 
will  make  very  little  difference  in  the 
reception  of  local  stations.  After  a  weak 
signal  has  been  tuned  in,  increasing  value 
of  balancing  condenser  will  increase  the 
strength  of  the  signal  up  to  a  point  where 
the  first  detector  tube  goes  into  oscilla- 
tion. 

(Turn  to  page  60) 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour        59 


$25.00  Prize  to  Radio  Fans 

Who  can  find  the  3rd  Circuit  in  the  3-circuit  tuners  being  placed 

on  the  market  as  "Low  Loss." 

The  "gyp"  dealers,  mud  radio  manufacturers  and  radio  morgues  surely  got  a  new  lease  on  life  when  they  picked 
that  slogan  from  Mr.  Kruse's  article  in  QST.  Most  of  the  manufacturers  were  handing  the  public  mud  sockets, 
water-soaked,  wooden  vario-couplers  and  variometers,  and  the  variable  condensers  would  make  a  good  sieve  for  any 
kitchen  mechanic. 

Any  tuner  on  the  market  today  that  advertises  Low  Loss  and  states 
there    is  no  dope  and  Lorenz  type   of  winding  is    sure   the    bunk. 

Only  one  dial  to  get  stations  and  the  other  to  increase  or  decrease  volume.  Kennedy  Tuner 
is  used  in  place  of  vario-coupler,  variometer  and  honey- comb  coils,  saving  the  cost  of  over 
$9.00  worth  of   unnecessary  parts  that  are  in   most  receiving  sets,  and  no  dead    end  losses. 


KENNEDY  TUNER   M^HPHfflMMMiH— » 


is  a  Two-Circuit  Tuner  that  gets  results 
and  was  manufactured  when  the  "gyp" 
artists  were  still  playing  with  taps  and 
wood. 

RESULTS  OF  EUROPEAN  TESTS 
1923  and  1924  : 

1923 — 2  LO,  London,  Eng. 

5  WA,  Cardiff,  Wales. 
1924— 5  NO,    Newcastle,    PTT, 
Lyons,  France. 

As  per  certification  from  Radio 
Broadcast. 


Most  Receiving  Sets  with  5,  6,  7  and  8 
tubes  call  it  a  "Radio  Triumph"  when 
they  hear  KGO  about  3  o'clock  in  the 
morning,  and  then  only  two  numbers. 
If  they  think  that  is  a  Radio  Triumph, 
let  them  read  this  photographic  con- 
firmation and  weep. 


13TO  Ui.Wor«lty 
»s«  ror».  H.Y. 
Oca.   BTta.1924 


Qjlr-<r^      /LP-^-o^-pt^-w 


K  -Gr.O  -t,  JT 


rJMJrJ-' 


November  24.  1924 


November  30,  1924 


INTERNATIONAL 

RADIO  BROADCAST  TEST 

Under  the  Auspices  of  RaOIO  BrOa£>c*st   Magazine 


3%*<-  "J 


atj% 


^bts  Gertifies  <-^5hat 


Located 

Has  assisted  and  participated  in  the  international  Radio  Test/  and  that 
information  received  and  checked  at  Radio  Broadcast  Laboratory  {Head- 
quarters of  the  Test)  indicates  successful  reception  of  lest  programs  from 
cooperating  European  Stations. 

cSJrthur  D{.  £ynch 


Garden  £ityt  5\ezv  York 
'December,  1924 


'Director  International  Tests 
Editor  "J^adio  broadcast 


Radio  Fans: — If   you    are   interested  in   the   best  radio 
parts  on  the  market,  send  your  orders  to  me. 

"We  do  not  handle  junk."  The  word  "cheap"  means 
the  kind  of  reception  you  are  going  to  get  on  that  cheap 
receiver  because  a  radio  receiver  is  as  good  as  its  cheapest 
part. 


KENNEDY  $£.00 
TUNER     M 

Including  Globe  Trotter 
Diagram 


KENNEDY  TUNER  users  must  be  satisfied.  Use  tuner  for  30 
days  at  my  expense  and  if  you  are  dissatisfied  I  will  refund  your 
money  with  a  smile. 

Send  for  Free  Diagram 


T.    J.    KENNEDY 

Radio  Globe  Trotter 
1360  University  Avenue   New  York,  N.  Y. 


*     Tested  and  Approved  by  RADIO  AGE     * 


I  60 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


Pending 


Multiple   reading  instrument 
with  self  contained  switch 


WATCH- 

Your  BATTERIES 
and  TUBES 

C  Mount  a  Jewell  No.  55  on 
your  set  and  check  your 
Batteries  of  your  filament 
voltages  from  the  panel  of 
your  set. 

d,  Every  radio  fan  should 
have  a  copy  of  our  15-A 
Radio  Catalog. 

Order  from  Dealer  *J* 


Jewell  Electrical  Instrument  Co. 


1650  Walnut  St. 


Chicago 


"25  Years  Making  Good  Instruments' 


FREE 

Bulletin 


i^ 


\ 


"Good  Condenser  Design" 

What  makes  a  good  condenser?  Send  for  this  free 
fo'der  and  post  yourself  on  today's  requirements. 
This  article  is  full  of  meat.  It  makes  plain  all  the 
electrical  as  well  as  the  mechanical  Qualities  of  a 
good  condenser.  .    , 

If  you  are  planning  to  build  a  receiving  set  or  to 
bring  your  present  one  up  to  date,  go  to  your  dealer 
and  ask  to  see  the  new 

Premier  "CROFOOT"  ££* 

"CROFOOT"  has  all  the  necessary  electrical  and 
mechanical  features.  It  is  a  real  low  loss  instrument. 
It  b&  the  lowest  minimum  capacity  yet  attained— 
.000005  M.  F.  and  the  greatest  tuning  ratio — I  to  74. 
Made  entirely  of  brass  and  hard  rubber  giving  re- 
markably low  skin  resistance  and  low  insulation 
leakage.  Semi-straight  line  plate  construction.  All 
plates  soldered;  a  feature  identified  by  the  "red 
stripe."  A  sturdy,  smooth  acting,  compact  and 
graceful  instrument.  Mounts  with  one  hole.  Ratios 
1  to  19.  1  to  42,  1  to  53  and  1  to  74.  Price  from  S2.75 
to  S3. 75.  Vernier  attachment  with  dial  75  cents 
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RADIO  AGE  Programs  are  noted  for  their  excellence.  Hear  one 
from  WEBH,  9  to  10  p.  m.,  Feb.  24th;  WLS,  7  to  8  p.  m.,  March  6;  and 
KYW  at  midnight,  March  7.    Each  a  Real  Show! 

*     Tested  and  Approved  by  RADIO  AGE 


An  Unusual  Seven  Tube 
Super-Het 

(Continued  from  "page  58.) 

The  balancing  condenser  should  always 
be  kept  just  below  this  point.  More 
balancing  condenser  capacity  may  be 
used  on  the  high  wavelengths  than  on. 
the  lower  waves. 

If  the  oscillator  dial  appears  broad  in 
tuning,  the  .0075  condenser  connected 
across  transformer  terminals  7  and  8 
should  be  adjusted  in  steps  of  .0005  by- 
adding  fixed  condensers  in  parallel  to  it 
until  the  oscillator  coupler  sharpens  up. 
This  will  probably  be  unnecessary  under 
average  conditions. 

Some  Final  Hints 

A  few  final  words  of  caution  will  not 
be  amiss.  It  is  absolutely  important 
that  all  by-pass  condensers  shown  be 
used,  and  they  should  be  of  approxi- 
mately the  values  specified,  although  the 
J^  MFD  condensers  may  range  as  high 
as  one  MFD  and  the  .002  condensers 
may  range  as  high  as  .005. 

If  any  hand  capacity  effect  is  noticed, 
it  indicates  that  too  high  a  value  of 
balancing  condenser  or  potentiometer 
is  being  used  or  that  by-pass  con- 
densers have  been  omitted,  or  are  defec- 
tive. In  some  cases,  due  to  the  difference 
in  potential  between  the  set  and  the 
operator's  body,  it  is  necessary  to 
ground  the  center  tap  of  the  loop  which 
is  connected  to  the  minus  side  of  the 
filament  line. 

If  an  antenna  is  to  be  used  with  the 
receiver,  an  extra  oscillator  coupler 
will  work  very  nicely  in  place  of  the  loop. 
It  should  not  be  necessary  except  under 
very  poor  conditions,  as  the  set  will  go 
below  the  noise  level  under  practically 
all  conditions  when  a  loop  is  used. 

If  care  has  been  used  in  the  assembly 
of  the  set  and  if  the  parts  used  have 
been  carefully  checked  and  are  of  first 
class  manufacture,  the  builder  will 
possess  a  set  of  which  he  will  have  every 
reason  to  be  proud — both  in  appearance 
and  operation. 


Experiments  with  the 
Double  Grid  Tube 

(Continued  from  page  58) 
rent  characteristic  just  beforethe  satura- 
tion point.      In   this  case,  a  proper    grid 
voltage    must    be    had    and   a  potentio- 
meter is  used  as  in  Fig.  2. 

It  has  been  shown  that  ordinary  hook- 
ups may  readily  be  equipped  with  double 
grid  tubes,  enabling  you  to  save  money  in 
the  buying  of  "B"  batteries.  It  is  even 
possible  not  to  use  any  "B"  batteries  at 
all,  the  return  leads  of  the  plate  and  the 
inner  grid  going  directly  to  the  positive 
post  of  the  "A"  battery.  A  sufficient 
positive  potential  as  regards  the  negative 
end  of  the  filament  is  thus  obtained  on 
grid  and  plate  to  insure  good  reception. 

In  the  above  hook-up,  use  is  only  made 
of  the  inner  grid  to  cut  down  the  internal 
resistance  of  the  tube.  Special  hook-ups 
which  will  be  taken  up  in  another  article 
will  make  use  of  a  grid-plate  circuit, 
where  a  great  amplification  is  obtained. 

The  tube  gives  also  very  good  results 
in  reflex  circuits,  of  which  we  shall  say 
more  in  the  second  part  of  this  article. 


RADIO  AGE  for  March,  1925 

A  Real  Coast-to-Coast 
R.  F.  Receiver 

(Conitnued  from  page  18) 

low  loss  coil  is  desired,  one  frame  with 
the  spokes  made  removable  will  do  for 
the  three  coils.  These  frames  may  be 
purchased  from  any  reliable  dealer  in 
radio  supplies  for  about   25  cents  each. 

The  spokes  on  these  frames  should  be 
about  one  and  one-half  inches  long,  and 
the  disc  should  measure  about  two  or 
two  and  one-half  inches  in  diameter. 
If  a  frame  of  these  dimensions  should 
prove  hard  to  locate,  it  can  be  made 
with  little  effort,  as  follows: — 

One  disc,  two  and  one-half  inches  in 
diameter,  will  be  turned  from  a  piece 
of  close  grained  wood  one-half  of  an 
inch  in  thickness;  and  seventeen  three- 
sixteenth  inch  holes  will  then  be  drilled 
around  the  circumference  of  the  disc 
to  a  depth  of  a  little  over  one-quarter 
of  an  inch.  These  holes  will  be  on 
centers  of  slightly  less  than  one-half 
of  an  inch  or  about  twenty-one  degrees 
apart. 

Seventeen  dowell  pins  will  then  be 
cut  from  three-sixteenth  inch  stock 
and  the  ends  rounded  and  finished  off 
so  as  not  to  injure  the  insulation  of  the 
wire  while  winding.  They  should  meas- 
ure one  and  three-quarter  inches  long. 
These  pins  will  then  be  placed  into  the 
seventeen  holes  in  the  disk  and  the  frame 
is  completed.  If  a  form  is  being  made, 
the  spokes  should  be  fitted  into  the  holes 
so  that  they  may  be  removed  easily; 
otherwise  they  should  fit  tight. 

Winding  the  Coils 

WHEN  the  form  or  frames  have  been 
completed,  the  coils  will  be  wound 
upon  them  as  follows,  using  number 
twenty-four,  twenty-six  or  twenty-eight 
double  silk  covered  copper  magnet  wire: 

The  primary  coil  will  have  six  com- 
plete turns  of  wire  wound  upon  the 
frame  and  the  ends  (P-l,  P-2)  left  about 
six  inches  long.  The  lead  (P-l)  will  be 
the  inside  lead  of  the  coil  and  will  be 
made  fast  to  one  of  the  spokes  by  looping 
it  around  that  spoke.  Now  bring  the 
wire  over  two  spokes  on  the  far  side 
of  the  coil,  crossing  over  to  the  near  side 
of  the  coil  between  the  second  and  third 
spoke's.  Pass  the  wire  over  the  third 
and  fourth  spokes  and  back  to  the  far 
side  of  the  coil  between  the  fourth  and 
fifth  spokes^  repeat  this  operation  of 
over  two  and  under  two  until  six  turns 
have  been  made  and  the  lead  (P-2) 
fastened  to  the  same  spoke  as  lead 
(P-l),  finishing  the  primary  coil. 

The  secondary  coil  will  be  wound 
directly  on  top  of  the  primary  coil  in 
the  same  manner  and  in  the  same  direc- 
tion as  the  primary  coil,  starting  with 
lead  (S-l),  making  fifty-five  complete 
turns  and  finishing  with  lead  (S-2), 
leaving  these  leads  about  six  inches  long. 

It  would  be  well  to  wind  the  primary 
coils  of  these  transformers  with  a  white 
colored  wire  and  the  secondary  coils 
with  a  green  or  dark  colored  wire  so  as 
to  more  easily  distinguish  each  coil  and 
the  different  leads. 

If  the  form  is  to  be  removed,  the  coil 

* 


The  Magazine  of  the  Hour         61 


Interior  view  of  a 
typical  set  you  can 
build  with  the  r.ew 
Tetos  KIT. 


mus  , 


3/ 


Don't  call  them  liars 
write  for  the  book  yourself ! 


VUHEN  you  run 
across  a  couple 
of  Telos  set  owners — 
as  everybody  does  now- 
adays— stop  before  you 
doubt  the  results  they 
talk  about.  For  you 
can  easily  find  out 
whether  such  power, 
selectivity,  at  so  little 
cost,  is  possible,  by 
using  the  coupon  below . 
When  you  do  find  out 
how  the  Telos  principle 
of  tuned  R.F.  has  been 
developed  —  how  it 
makes  three  R.F.  stages 
entirely  practical — how 
the  A.  F.  is  superim- 
posed (renexed)  on  the 
R.F.  tubes — how"Uni- 
control  works" — how 
5,   6,   and  7  dry  cell 


tubes  are  made  to  oper- 
ate with  half  the  usual 
plate  current  —  then 
you  will  no  longer  doubt 
— but  you  will  want  a 
Telos  set  yourself. 
And  you  will  also  find 
that  you  can  easily 
build  any  one  of  the 
many  interesting  Telos 
sets  in  a  single  after- 
noon —  the  essential 
Telos  instruments  to 
build  scores  of  circuits, 
based  on  the  Telos  prin- 
ciple, are  all  in  the 
Telos  Kit. 

So  fill  out  the  coupon 
now!  Don't  doubt  — 
know  for  yourself  what 
Telos    really   does! 
DANZIGER- JONES,  Inc. 

Dept.  C.  25  Waverly  Place 

NEW  YORK,  N.  Y. 


* | 

a    f)k    m    f\    #""•  l    Danziger- Jones,  Inc., 

f    f~?   f I  I    #  ^^  DePt-  C,  25  Waverly  Place,  I 

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■w-^  ■*    •  J    Send  me  at  once  your  booklet  "The  I 

I  9  f^  f^M    f    f\        '    KIT  of  a  Thousand  Possibilities." 

IhCvtAjvLf        !    Name - I 

l^~v~^-~-~'~^~         ~  a  aia    Address _ |~ ™ 

Tested  and  Approved  by  RADIO  AGE     ¥. 


62         RADIO  AGE  for  March,  1925 


This  Tag 

Insures  Success      $f» 
of  Your  Super 


It  remained  for  Silver-Marshall  to 
produce  long-wave  transformers  so  uni- 
form that  individual  amplification 
curves  could  be  supplied  with  each 
instrument.  The  idea  is  revolutionary. 
It  establishes  a  standard  of  excellence 
every  progressive  manufacturer  will  be 
forced  to  adopt.  It  demonstrates  again 
the  fact  that  S-M  engineering  methods- 
are  always  a  year  ahead  of  the  industry. 
Now,  you  can  build  your  super  as  an 
engineer  builds  a  bridge — after  a  defi- 
nite plan — with   assurance  of  success. 


Its  Curve 

Is  on 
the    Tag 


The  "Why  of  Silver  Supers" 

Send  for  the  "Why  of  Silver  Supers."  It  tells  you  all 
about  the  seven-tube  dry-cell  set  that  gives  consistent 
coast  to  coast  reception  with  speaker  volume  on  an 
eighteen-inch  loop.     It's  Free. 

McMurdo  Silver's  book  on  the  "Super"  is  the  most  com- 
plete and  light-shedding  book  of  its  kind  in  print. 
Price - - 50c 


Story  of  the  Curve 

The  curve  of  each  TWO-TEN 
(iron-core  inter-stage)  and  TWO- 
ELEVEN  (filter)  transformer  is 
plotted  in  our  laboratory — re- 
corded on  a  tag,  and  tied  to  the 
instrument.  It  shows  the  peak — 
side-bands  passed — amplification 
factor.  Both  peak  at  5000  meters 
and  pass  an  11  Kilocycle  side- 
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with  identical  peaks  and  separate 
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THE  FOUR-TUBE  KNOCKOUT 

This  is  the  set  described  in  the  March  issue  of  Radio 
Broadcast — the  set  on  which  a  green"  operator  in 
Chicago  brought  in  twenty-seven  stations  from  coast 
to  coast  on  the  loud-speaker,  in  daylight. 


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the 


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LOW-LOSS  COILS 

The  R.F.  Coupler  and  Antenna 
coil  designed  by  Mr.  Silver  for  use 
in  the  KNOCKOUT  are  respons- 
ible for  the  remarkable  records 
already  established  by  this  set. 
They  show  the  lowest  losses  of 
any  coils  obtainable.  Send  for 
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The  Magazine  of  the  Hour 

should  be  painted  with  a  good  solution 
of  collodium  and  allowed  to  harden 
before  the  spokes  are  removed.  This 
will  take  about  fifteen  minutes.  After 
the  form  has  been  removed,  the  inside 
and  outside  edges  of  the  coil  should  be 
treated  with  this  solution  to  prevent  the 
wires  from  coming  loose.  Three  such 
coils  are  required. 

Collodium  is  a  solution  of  gun  cotton 
in  ether,  and  may  be  purchased  at  almost 
any  drug  store.  Two  ounces  will  be 
sufficient  and  should  cost  about  ten 
cents. 

When  the  three  coils  have  been  formed 
and  the  frame  removed,  insert  one  of 
the  dowell  pins  in  each  coil  at  the  point 
where  the  leads  or  ends  of  the  coil  ter- 
minate and  make  fast  with  cotton  or 
silk  thread,  as  shown  in  Figure  2,  and 
the  coils  are  ready  to  be  mounted. 

The  transformers  used  for  radio  fre- 
quency amplification  should  be  as  near 
alike  electrically  as  possible.  Therefore, 
it  would  be  well  to  use  care  in  the  wind- 
ing of  the  above  coils  to  keep  the  tension 
of  the  wire  the  same  on  all  three  of  the 
coils,  in  order  not  to  have  the  winding 
more  dense  on  one  than  on  another,  or 
it  would  be  well  to  match  these  coils 
by  use  of  the  slide  wire  bridge  described 
in  the  February  issue  of  RADIO  AGE. 

Assembly  of  the  Parts 

'T'HE  first  step  in  the  assembly  of  the 
J-  set  will  be  to  mount  the  five  tube 
sockets  (M-l  to  M-5)  on  the  shelf  and 
the  three  condensers  (C-l,  C-2,  C-3),  the 
filament  control  rheostat  (R)  and  the  two 
jacks  (P)  and  (S)  to  the  panel;  then 
drill  the  holes  in  the  shelf  for  passing  the 
wiring  to  the  different  pieces  and  for 
mounting  the  three  radio  frequency 
transformers    (R-l,    R-2,    R-3). 

Five  binding  posts  will  then  be  mounted 
on  the  right  end  of  the  shelf  and  desig- 
nated (G)  (-)  (A+)  (BD)  and  (B  +  ). 
One  binding  post  will  then  be  mounted 
on  the  left  end  of  the  shelf  and  desig- 
nated (A).  The  audio  frequency  trans- 
former (T-l)-  will  be  mounted  on  the 
extreme  right  end  on  the  under  side  of  the 
shelf,  as  far  back  as  possible.  This 
transformer  should  be  placed  so  that  the 
ends  of  the  winding  are  opposite  to  the 
panel  or  so  that  the  core  of  the  trans- 
former is  at  right  angles  to  the  panel. 

The  audio  transformer  (T-2)  will  then 
be  mounted  between  the  jacks  (P)  and 
(S)  on  the  top  side  of  the  shelf  and  as 
close  to  the  panel  as  possible.  This 
transformer  should  be  placed  so  that  the 
ends  of  the  winding  are  in  line  with 
the  panel,  or  so  that  the  core  of  the 
transformer  is  parallel  to  the  panel. 
This  will  place  this  unit  so  that  it  will 
be  at  or  close  to  an  angle  of  sixty  degrees 
with  the  third  radio  frequency  trans- 
former (R-3). 

Our  radio  frequency  transformers  will 
not  be  mounted  until  the  wiring  has  been 
completed  for  the  parts  already  assem- 
bled, as  they  are  rather  delicate  and 
would  be  easily  damaged  even  with 
careful  handling. 


Wiring  the  Set 

As  will  be  noted  in  the  pictures  of  the 


¥     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  March,  1925 


receiver,  the  customary  bus-work  has 
been  omitted  and  very  little  wiring  is 
exposed  on  the  top  of  the  shelf.  Little 
need  be  said  about  how  to  run  the  leads, 
except  that  they  should  be  as  short  as 
possible  and  no  two  leads  run  parallel 
for  any  distance.  This  is  easily  done 
when  the  wiring  is  concealed  as  the 
tendency  to  beautify  instead  of  simplify 
prevails  when  wiring  is  exposed  to  view. 
Number  eighteen  double  cotton  cov- 
ered bell  wire,  treated  with  paraffin, 
was  used  in  this  set,  it  being  plenty 
large  enough  to  carry  any  currents 
passing  through  the  xeceiver,  and  is 
sufficiently  flexible  to  permit  handling. 
All  leads  should  be  soldered  to  ter- 
minals or  to  other  leads  where  they  are 
joined.  Too  much  stress  cannot  be  put 
to  this  point,  as  poor  contact  to  the  ter- 
minals or  junctions  is  the  direct  cause 
of  over  half  of  the  failures  among  amateur 
set  builders.  It  is  also  one  of  the  most 
difficult  causes  of  trouble  to  locate,  the 
fault  often  being  laid  to  a  piece  of  equip- 
ment, which  is  discarded  and  a  new 
piece  put  in  its  place  with  the  terminals 
all  soldered  tight  and  cleaned,  whereas 
resoldering  the  leads  to  the  original 
piece  of  apparatus  would  have  made  it 
function  as  well  as  the  new  piece. 

A  well  known  radio  engineer  recently 
made  the  remark  that  when  he  soldered 
a  terminal  or  junction,  he  tried  his  level 
best  to  pull  it  apart.  If  it  stays  put,  he 
knows  he  has  a  good  contact;  if  it  comes 
off,  he  is  one  jump  ahead  of  trouble,  and 
I  think  his  policy  is  a  good  one  to  follow, 
as  soldering  is  not  merely  to  have  a  hot 
iron  and  a  piece  of  solder,  but  one  of  the 
most  important  operations  of  assembling 
a  receiving  set. 

When  the  leads  have  all  been  soldered 
to  their  respective  terminals  on  the 
mounted  apparatus,  we  will  return  to 
the  radio  frequency  transformers  (R-l, 
R-2,  R-3)  which  will  be  mounted  to  the 
shelf  as  shown  in  Figure  2,  using  glue 
or  some  such  method  to  make  the  dowell 
pins  rigid  in  their  mounting  holes  and 
to  prevent  them  from  turning  out  of 
their  required  angles. 

Placing  the  Coils 

"T^HESE  coils  should  be  placed  on  an 
-*■  angle    of    about    sixty    degrees    with 

respect   to   the    panel   and   on    four-inch 

centers  as  previously  covered. 

They  will  be  wired  to  the  set  as  follows: 
Coil  R-l  The  inside  lead  (P-l) 
of  this  coil  will  be  connected  to  the 
binding  post  A.  Lead  (P-2)  will  be 
connected  to  the  filament  post  of  the 
tube  socket  (M-l)  marked  (-).  Lead 
(S-l)  will  be  connected  to  the  stator 
plates  of  the  condenser  (C-l)  and  to 
the  filament  post  of  the  tube  socket 
(M-l)  marked  (-)  and  lead  (S-2) 
will  be  connected  to  the  rotor  plates 
of  the  condenser  (C-l)  and  to  the 
grid  terminal  of  the  tube  socket  (M-l) 
marked  (G). 

Coil  R-2  The  inside  lead  of  this 
coil,  (P-l),  will  be  connected  to  the 
plate  terminal  of  the  tube  socket  (M-l) 
marked  (P).  Lead  (P-2)  will  be  con- 
nected to  the  binding  post  B+.  Lead 
(S-l)  will  be  connected  to  the  stator 
plates   of    the    condenser  (C-2)  and  to 


The  Magazine  of  the  Hour        63 


d he  Heart 
of  the 
Radio 


We  shall  be  glad 
to  send  new  cir- 
cuits with  com- 
plete working  di- 
agrams. Grimes 
3XP  Inverse  Du- 
plex, Jefferson 
Baby  Grand  6 
Tube  Superhet- 
erodyne, Jeffer- 
son 8  tube  Sup- 
erheterodyne, 
and  many 
others.  Any  of 
these  will  be  sent 
upon  receipt  of 
five  cents  in 
stamps  to  cover 
postage. 


# 


FAINT,  trembling  impulses  are 
caught  from  the  air  and  am- 
plified thousands  upon  thou- 
sands of  times.  Finally  transformed 
into  audible  sounds  by  your  loud 
speaker,  they  are  either  painfully 
distorted  or  lifelike  in  purity  of 
tone.  Which  it  will  be,  depends 
largely  upon  your  transformer. 

For  the  transformer  is  of  the  ut- 
most importance  in  your  radio  set. 
Each  minute  sound  vibration  com- 
ing from  the  detector  is  magnified 
and  reissued  with  a  stronger  pulse 
— lending  volume  and  clarity  to 
your  radio  reception. 

Jefferson  Super  Sensitive  Trans- 
formers are  designed  to  receive  over 
the  entire  musical  range  without 
howling  or  distortion.  Radio  au- 
thorities the  world  over  recognize 
the  excellent  performance  of  these 
wonderful  transformers  and  specify 
their  use  in  new  circuits. 

Handled  by  the  better  dealers 

and  jobbers. 

A    superior    transformer    at    a 

price  attractively  low. 


Jefferson  Electric  Mfg.  Co. 


507  So.  Green  St. 


Chicago 


Manufacturers  of 


Radio     Transformers 
Bell     Ringing      Trans- 
formers 
Sign    Lighting    Trans' 
form  ers 

Automobile  Ignition 
Coils 

Jump    Spark   —    Make 
and  Break   Coils 


Auto  Transformers 
Testing  Instruments 
Toy  Transformers 
Furnace  and  Oil  Burn- 
er Transformers 
Oil     Burner      Ignition 

Coils 
Special   high    and    low 
voltage  transformers 


v  If  effevson 
tlTransfoymers 


Tested  and  Approved  by   RADIO   AGE     * 


64        RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


% 

e 
e 


Tune  by  Sight 

Tune  your  favorite  stations  once, 
mark  them  on  the  Ultra-Vernier, 
then  forget  wave  lengths.     Ted-      ^  ^-^ 
ious  tuning,  blind  fumbling  and      9  •P.50 
guessing  are   over   for  all  time.  M 

Now  it's  possible  to  pick  your  enter- 
tainment from  the  radio  program  and 
turn  the  dial  instantly,  accurately,  to 
your  station  and  know  your  receiver 
is  tuned  with  infinite  precision. 
The  silvered  Ultra-Vernier  dial  mounts 
fast  to  panel.  Single  control  20-1 
ratio,  operates  vernier  for  hair-split- 
ting adjustment  and  governs  station 
indicator.  Replace  your  old  dials  with 
Ultra-Verniers.  You've  never  known 
such  tuning  ease. 

Write  for  Descriptive  Circular 

ULTI^VSRniSR,  * 

TUNING       CONTROL 


Designed  by  R. 
E.  Lacault,  E. 
E-,  A.  M.  I.  R. 
E ,  inventor  of 
the  famous  Ul- 
tradyne  circuit. 
This  monogram 
seal     (R.     E.    L.) 

ance  of  Lacault 
design. 


Made 

by 

the 

Ham 

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und 

Mfg. 

Co., 

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assurance 

of 

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ity 

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ced 

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for   the     Ph 

Radio 

Corpora- 

tion. 

At 

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ther- 

wise 

send 

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chase 

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and 

ill   be 

postpaid. 

PHENIX     RADIO       CORPORATION 

3-9  Beekman  Street 
NEW   YORK    CITY 


f  its Jirid  Leak 


'Ml'JUl 


LL 


FRESHMAN  PLUNGER    \ 

TIME      VARIABLE      GRID        LEAK 

was  designed  especially  for  rbe  ron-technical  set 
owner  who  can  replace  in  an  instant  the  fixed 
grid  leak  with  this  new,  efficient  cartridge  type 
Variable  Grid  Leak:  without  requiring  the 
Change  of  a  single  wire. 

At  your  dealer  or  by  ma' 

postpaid.      Write    fo 
free  catalogue.' 


New   Long    Distance  Crystal 
Gives  Remarkable  Results 

A  recent  invention  in  crystals  is  amaz- 
ing Reflex  and  Crystal  Set  owners  every- 
where. It  is  stated  that  this  marvelous 
Crystal  gets  distant  stations  loud  and 
clear,  and  there  is  no  disagreeable  "hunt- 
ing" for  spots  because  the  entire  surface 
is  sensitive.  Many  are  finding  it  far  su- 
perior for  reflex  work  and  claim  it  the 
last  word  in  mounted  synthetic  crystals. 
A  Trial  Costs  You  Nothing 

In  order  to  introduce  his  invention,  the 
owner,  Mr.  Hick,  offers  you  two  ?1.00  Crys- 
tals for  the  price  of  one.  Sell  one,  and  put 
the  other  on  your  own  set  without  cost  to 
you.  Just  send  name  and  address  to  Mr. 
Hick,  Dept.  9,  1018  S.  Wabash  Ave.,  Chi- 
cago. Pay  postman  $1.00  (plus  postage). 
Unless  you  are  absolutely  satisfied,  write 
Mr.  Hick,  and  money  will  be  cheerfully  re- 
funded. 

*     Tested  and  Approved  by  RADIO  AGE     * 


the  filament  post  of  the  tube  socket 
(M-2)  marked  (-)  and  lead  (S-2)  will 
be  connected  to  the  rotor  plates  of 
the  condenser  (C-2)  and  to  the  grid 
terminal  of  the  tube  socket  (M-2) 
marked  (G). 

Coil  R-3  The  inside  lead  of  this 
coil,  (P-l),  will  be  connected  to  the 
plate  terminal  of  the  tube  socket 
(M-2)  marked  (P).  Lead  (P-2)  will 
be  connected  to  the  binding  post  B  +  . 
Lead  (S-l)  will  be  connected  to  the 
stator  plates  of  the  condenser  (C-3) 
and  to  the  filament  post  of  the  tube 
socket  (M-3)  marked  (+),  and  lead 
(S-2)  will  be  connected  to  the  rotor 
plates  of  the  condenser  (C-3)  and  to 
the  No.  1  terminal  of  the  grid  leak 
and  condenser  (GL).  The  terminal 
of  the  grid  leak  and  condenser  (No.  2) 
will  then  be  connected  to  the  grid  ter- 
minal of  the  tube  socket  (M-3)  marked 
(G)  and  the  wiring  will  be  complete. 

Testing  Out  the  Wiring 

For  safety,  it  would  be  a  good  plan  to 
test  the  wiring  of  the  set  to  see  if  the 
connections  are  all  in  their  proper  place 
and  to  make  sure  that  a  high  voltage 
(B)  battery  lead  is  not  crossed  with 
the  filament  or  "A"  battery  leads.  This 
will  often  save  many  dollars'  worth  of 
tubes,  and  while  the  builder  is  usually 
careful  in  this  respect,  it  is  a  good  plan 
to  make  sure  and  some  disappointing 
moments  may  be  avoided  when  the  set 
is  put  into  operation.  The  first  step 
in  a  simple  test  of  the  wiring  will  be  to 
connect  the  negative  side  of  the  plate 
or  "B"  battery  to  the  binding  posts 
(G)  and  (— )  and  the  positive  side  of 
this  battery  to  the  binding  posts  (BD) 
and  (B+),  then  secure  a  small  volt- 
meter or  buzzer  and  attach  two  leads 
to  the  terminals  and  place  them  across 
the  filament  posts  of  each  tube  socket. 
If  a  flow  of  current  takes  place,  it  will 
be  caused  by  the  "B"  battery,  and  should 
be  eliminated  before  any  tubes  are  put 
into  the  sockets.  If  no  current  flows, 
the  filaments  of  the  tubes  will  be  safe. 

All  of  the  wiring  in  the  receiver  may 
be  tested  with  the  voltmeter  or  buzzer 
in  connection  with  the  plate  battery 
and  will  prove  time  well  spent. 

After  the  set  has  been  wired  and 
tested,  it  should  be  put  into  the  cabinet 
and  made  ready  for  operation.  The  first 
step  will  be  to  connect  the  plate  or  "B" 
batteries.  The  negative  side  of  the  first 
battery  will  be  connected  to  the  binding 
post  (  — )  and  a  tap  taken  off  at  twenty- 
two  volts,  which  will  be  connected  to 
the  binding  post  (BD).  The  positive 
post  of  the  battery,  which  should  be 
ninety  volts,  will  be  connected  to  the 
binding  post  (B  +  ).  The  filament 
battery  will  then  be  connected  to  the 
set.  This  should  be  a  six  volt  battery. 
The  negative  post  of  this  battery  will 
be  connected  to  the  binding  post  (  — ) 
and  the  positive  post  to  the  binding 
post  (A  +  ). 

The  ground  lead  will  be  connected  to 
the  binding  post  (G)  and  the  antenna 
to  the  binding  post  (A). 

A  single  wire,  flat  top  antenna  about 
seventy-five  feet  in  length  with  a  lead-in 


RADIO  AGE  for  March,  1925 


of  not  over  twenty-five  feet  is  recom- 
mended for  use  with  this  set,  as  it  will 
allow  for  sharp  tuning  and  will  be  large 
enough  for  any  purpose.  A  smaller 
antenna  will  serve  as  well,  however, 
and  when  close  to  a  broadcasting  station, 
may  prove  to  advantage  in  that  it  will 
make  more  sharp  tuning  possible. 

Operation  of  the  Set 

When  the  set  has  been  connected  to 
the  batteries,  the  ground  and  to  the 
antenna,  turn  the  tube  control  rheostat 
(R)  to  the  "off"  position,  and  insert 
the  tubes  in  their  respective  sockets. 
Turn  the  rheostat  on  gradually  until 
the  tube  filaments  are  caused  to  glow, 
Set  the  dials  (C-l,  C-2,  C-3)  at  about 
twenty-five.  This  should  tune  the  set 
to  a  wave  of  about  300  meters.  Move  the 
three  dials  gradually  around  until  a 
station  is  heard;  then  turn  the  rheostat 
(R)  until  a  point  is  reached  where  the 
best  reception  is  obtained. 

The  same  procedure  will  be  taken  to 
tune  the  set  to  other  waves,  remembering 
that  the  three  dials  (C-l,  C-2,  C-3)  will 
always  be  at  or  near  the  same  point  if 
the  transformer  coils  (R-l,  R-2,  R-3) 
have  been  matched  close  to  one  another. 
And  the  set  may  easily  be  logged  for 
wavelength  or  for  stations,  making  it 
possible  to  turn  to  the  place  desired 
without  the  customary  fishing. 


Penetrating  Through  the 
Strong  "Locals" 

(Continued  from  page  12) 

Cuba,  Canada,  etc.  In  such  a  location, 
some  of  the  more  powerful  or  better  sit- 
uated DX  stations  behave  much  as  locals 
do  for  city-dwellers.  For  instance,  DX 
stations  coming  through  in  Virginia  so  well 
that  they  would  be  classed  as  locals  in 
the  city  are,  KDKA,  WBZ,  WSB,  WEBH. 
WQJ,  WOC,  etc.,  and  when  reception  of 
other  stations  very  close  to  these  in 
wavelength  is  wanted,  the  penetrator 
switch  is  used  on  the  2-2  combination 
to  remove  interference   from   them. 

Such  a  receiver  is  of  special  interest 
where  a  good  antenna  system  is  available. 
since  the  double  tickler  control  main- 
tains the  outfit  at  its  most  sensitive  state 
on  any  wavelengtn.  Ordinary  tuned 
R.  F.  receivers  having  no  regeneration 
or  tickler  controls  are  in  reality  supreme 
for  only  a  small  band  of  waves,  usually 
rather  short  waves.  Below  this  band 
oscillation  is  usually  present,  and  above 
it  the  sensitivity  falls  off  greatly.  Tuned 
R.  F.  users  who  have  tried  reception  on 
waves  higher  than  450  will  realize  the 
truth  of  this  quite  readily. 

When  tested  in  about  a  dozen  different 
and  difficult  locations  in  New  York  city, 
the  penetrator  demonstrated  its  ability 
to  tune  through  locals  and  receive  out- 
of-town  stations  despite  interference 
from  stations  within  a  quarter  and  half 
mile.  For  instance,  in  a  situation  about 
twelve  blocks  from  WJZ,  WJY  and  WHX 
stations  KDKA,  WBZ,  WGY,  WTAM 
could  be  heard  successfully,  whereas 
with  the  6-6  combination  (representing 
the  average  tuned  R.  F.  outfit)  even  the 
locals  overlapped   each   other. 


^tfoed 


The  Magazine  of  the  Hour         65 


QpQwSgf 


Maqnatrons  are 
manufactured  and 
guaranteed  by  the 
Conrwwey  Elec- 
tric Laboratories 
New  YorH  City. 


/ 


MAGNATRONS  have 
reached  that  degree  of 
excellence  where  the  mere 
name  is  synonymous  with 
the  very  best  in  vacuum 
tubes.  You  have  but  to  use 
MAGNATRONS  to  form  the 
same  opinion. 

MAGNATRONS  have 
received  the  unqualified  ap- 
proval of  radio  fans  and 
radio  engineers  alike.  And 
small  wonder — when  you 
realize  that  the  design  and 
manufacture  of  MAGNA- 
TRONS is  carried  on  by  an 
organization  of  men  who 
have  devoted  a  decade  and 
more  to  vacuum  tube  prob- 
lems. 

MAGNATRONS  are  made  in 
three  types:  the  DC-201A, 
the  DC-199  with  large  base, 
and  the  DC-199  with  mina- 
ture  base.  Your  dealer  will 
gladly  recommend  all  of 
them  to  you. 


Apparatus 

THE  parts  employed  in  the  Penetrator 
are  as  follows: 

2   Low  loss  three  circuit  couplers 

2  Low  loss  variable  condensers  to 
match 

2  double  circuit  jacks 

1   single  circuit  jack 

5    tube   sockets 

4  rheostats,  10  ohms  each 

1    filament  switch 

1  double  pole  double  throw  jack  or 
anti-capacity  switch 

1  R-4  R.  F.  transformer 

1  grid  leak,  2  meg.,  and  grid  con- 
denser,   .00025   mfds. 

1  fixed  condenser  .002  mfds. 

9    binding    posts 

1   binding  post  panel 

1  panel,  16  by  24  inches 

1  baseboard   10  by  22  inches 

2  3-inch  dials  for  ticklers 
2  4-inch  or  vernier  dials  for  condensers 

¥     Tested  and  Approved  by  RADIO  AGE     * 


4   rheostat    dials 

Wire   for   connections 

As  mentioned,  the  coupler  tickler  coils 
should  be  reduced  to  fifteen  turns  each. 
This  can  either  be  done  by  cutting  one 
end  and  tapping  oy  a  soldered  joint  at 
the  15th  turn,  or  else  by  completely  re- 
moving the  tickler  and  winding  another 
coil  of  15  turns  to  replace  it.  This  extra 
coil  may  be  wound  in  a  ring  or  "dough- 
nut" and  bound  together  by  a  few  strips 
of  thread.  Low  loss  form  is  not  of  value 
in  the  plate  circuit,  but  is  of  prime  im- 
portance in  the  primary  and  grid  cir- 
cuits of  the  coupler. 

The  grid  condenser  and  leak  should 
preferably  be  a  combination  instrument. 
Binding  posts  are  placed  at  the  rear  of 
the  baseboard.  Six  or  seven  posts  will 
answer,  providing  some  of  them  are 
combined,  as  is  quite  feasible.  Binding 
post  strips  may  be  had  either  with  or 
(Turn  to  page  77) 


66         RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


A  New  Socket 

that  means 

Better  Reception! 

L. 


* 


After  exhaustive  research,  our  engineers  have 
developed  VIRALON,  a  special  glass,  processed 
for  100%  efficiency.  Sturdy  and  rugged,  abso- 
lutely heat  and  moisture  proof,  and  unaffpcted 
by  those  influences  that  commonly  make 
rubber,  rubber  derivatives,  porcelain  or  vitreous 
products  so  inefficient. 

Other  exclusive  features  are  Ezyklean  Contacts  (proof  against 
corrosion) — One-Piece  Contact  Spring — Handy  Soldering 
Terminals,  etc.     Price  SI. 25,  standard  size. 

Write  for  interesting  pamphlet 

If  your  dealer  cannot  supply  you,  send  us  S1.25  and  parce' 
post  to  cover  each  socket. 

DURAY  RADIO  CORPORATION 

Dept.  15.  263  Washington  Ave.,  Newark,   N.  J. 

DURAY 


ALL-GLASS 

VI  RALO  N 

SOCKET 


RECO      * 

RADIO 

RECEIVER 


4-TUBE  RADIO  FREQUENCY 


Equal  to  any  5  or  6  tube  set 
on  the  market. 

Beautiful  Tone  Quality.  Long 
Distance  Stations  brought  in 
easily  with  volume  and  clarity. 

Enclosed  in  a  beautiful  solid 
walnut  cabinet  with  Duco 
Two-Tone  Finish. 

Price  ?8522  Chicago 


DEALERS  ■ 


-Write  for  our  liberal 
sales  plan 


OTHER  HIGH  GRADE 
PRODUCTS 

RECO  STORAGE  BATTERIES 

CABINETS  —  CONSOLES 

AMPLITRON  TUBES 

ARMSTRONG  CABINET  SPEAKERS 

DAVENPORT  -  HICKORY 
CORPORATION 

329  So.  LA  SALLE  ST. 
CHICAGO  ILLINOIS 


Perfecting  the  "Baby 
Grand  Super" 

(  Continued  from  page  24) 
conveyed   back   through   the   audio   and 
amplified,    distorting   the    reception. 

Oscillator  Tube  Rheostat  in  Previous 
Circuits 

ONE  control  has  been  used  for  the 
entire  six  tubes.  It  has  been  found 
desirable  to  control  the  operation  of 
the  oscillator  tube  independently  of 
the  other  tubes.  This  is  for  the  reason 
that  the  incoming  impulse  should  be 
nicely  balanced  with  the  local  oscilla- 
tions. As  tube  characteristics  change, 
one  tube  may  give  the  proper  degree  of 
local  oscillation  when  working  in  com- 
mon with  the  other  tubes,  whereas  a 
different  tube  used  in  the  oscillator 
would  require  separate  control.  By 
providing  separate  control,  this  variation 
in  tubes  is  taken  care  of. 

While  a  great  deal  has  been  said  about 
this  operation  of  the  super-heterodyne 
circuit,  yet  it  will  by  all  means  bear 
repeating.  It  is  one  place  where  success 
or  failure  may  be  encountered  without 
warning.  Unless  you  have  had  a  lot 
of  experience  in  the  use  of  regeneration, 
you  will  not  recognize  the  symptoms 
which  will  tell  you  whether  you  have  too 
much  or  too  little  regeneration.  Too 
little  regeneration,  of  course,  will  prevent 
the  securing  of  the  full  quota  of  distant 
stations.  Too  much  regeneration  will 
blur,  if  not  altogether  obliterate,  the 
reception.  If  the  small  condenser  does 
not  respond  readily  when  being  turned, 
it  is  an  indication  that  the  capacity  is 
either  too  high  or  too  low. 

If  the  condenser  has  the  right  number 
of  plates,  regeneration  can  be  identified 
by  the  peculiar  rushing  noise  known  to 
all  regenerative  circuits.  As  there  .  are 
no  condensers  on  the  market,  so  far  as 
the  writer  knows,  that  will  give  exactly 
the  right  capacity,  it  will  be  necessary 
to  use  the  same  condenser  as  used  in  this 
layout  and  then  remove  plates  from  the 
rotor  one  at  a  time  until  with  the  rotor 
half  turned  in,  you  have  a  good  amount 
of  regeneration  and  plenty  of  margin 
for  filament  control. 

As  it  is  contrary  to  the  policy  os 
RADIO  AGE,  in  common  with  most 
other  radio  publications,  to  give  a  list  of 
the  necessary  parts,  the  writer  wishes  to 
say  that  he  will  be  glad  to  furnish  a  com- 
plete list  of  parts  and  dimensional  layout  to 
all  those  who  are  interested  and  upon  re- 
ceipt of  5c  in  stampsto  cover  postage. 

It  is  important  that  specifications 
both  as  to  layout  and  parts  be  followed 
closely,  inasmuch  as  each  super-hetero- 
dyne circuit  is  a  law  unto  itself.  Operat- 
ing as  it  does  at  a  predetermined  fre- 
quency, there  is  no  possibility  of  sub- 
stituting one  make  of  apparatus  for 
another  and  of  securing  even  the  sem- 
blance of  efficiency.  This  has  no  refer- 
ence to  the  comparative  merits  of  appa- 
ratus, but  rather  the  operating  fre- 
quency. The  diagrams  will  show  the 
correct  position  for  each  wire  and  piece 
of  apparatus,  and  the  list  of  parts  will 
indicate  how  and  where  to  secure  them. 

Specifications  will  be  given  for  the 
construction  of  a  loop  such  as  used  on 
*     Tested  and  Approved  by  RADIO  AGE 


7/*  DAVEN 

RESISTANCE  COUPLED 

AMPLIFIER  KIT 


Those  who  build  their  own  can 
easily  achieve  perfect  repro- 
duction. There's  nothing  to 
equal  Resistance  Coupling.     The 

DAVEN    AMPLIFIER 
KIT 

comes  with  full  instructions  for 
assembly.  Easy  to  build — effi- 
cient in  operation.  ( Without 
sockets   and  condensers.) 

Supplied    in    either   3   or  4    stages. 

Sold  Everywhere. 

Ask  your  dealer  for  the  "RESISTOR 

BIAOTJAX."    it's    full    of    information 

on   Resistance    Coupling.      Fries    25c. 

Postpaid    35c. 

DAVEN  RADIO  CORP. 

"Resistor  Specialists" 
Newark,  New  Jersey 


The  Famous  Truly  Portable 

Telmaco  P-l  Receiver 

Four  Tubes  Do  the  Work  of  7 

Coast-to-coast  reception.  Aerial,  load  speaker,  and 
batteries  self-contained.  Carry  from  room  to  room- 
take  it  anywhere.  Size  8*xl0"x  18*.  Total  weight  only 
26  lbs.  Complete  with  tubes  and  batteries,  $19C  00 
5147.50.    Receiver  only fX*W.ww 

P-l  Kit  Saves  You  Money! 

In  response  to  a  popular  demand  we  now  offer  the 
Telmaco  P-l  Receiver  in  kit  form.  This  contains  all 
parts,  as  built  by  us,  including  case,  drilled  and  en- 
graved panel,  and  Illustrated  instructions.  $Qfl  00 

Complete  kit *OU.ww 

Ask  your  dealer  or  write  us.  Descriptive  folder  free. 
cRladio  'Division  : 

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20  So.  Wells  St.    Dept.  Cf  Chicago,  111. 


Syality  *Hadio  Exclusively  <%>    Established  1928 


MARSHALL  RadSeFcreei?ersDey 

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this  set,  as  well  as  the  cabinet  in  which 
the  set  is  placed.  Those  who  wish  to 
use  the  set  as  a  portable  one  can  follow 
instructions  just  as  given.  Those  who 
wish  to  use  the  set  indoors  entirely 
may  omit  the  bottom  portion  of  the 
cabinet,  and  run  the  binding  posts  out  of 
the  back  so  that  stationary  "A"  and 
"B"  batteries  may  be  attached. 

As  there  are  six  tubes  in  this  set,  the 
total  current  consumption  with  the  tubes 
in  normal  operation  will  be  about  1-2 
ampere.  The  six  dry  cells  hooked  up 
in  parallel  will  serve  to  furnish  current 
for  the  filaments  over  a  considerable 
period  of  time.  The  small  "B"  batteries 
will  last  about  an  equal  length  of  time, 
depending,  of  course,  upon  how  fre- 
quently and  how  long  the  set  is  used. 
When  the  set  is  used  considerably  as  a 
postable  set,  it  probably  would  be  well 
to  carry  a  pair  of  45  Volt  "B"  batteries 
of  large  size  and  use  them  instead  of  the 
small  size. 

OPERATING  on  a  loop,  shown  in 
illustration,  this  little  set  during 
the  last  two  or  three  months  has  con- 
stantly brought  in  stations  all  over  the 
United  States,  including  the  west  coast, 
and  all  of  them  on  the  loud  speaker. 
It  has  been  operated  within  twenty- 
two  miles  of  Chicago  during  the  large 
part  of  this  time  and  cuts  through  the 
Chicago  stations  without  any  difficulty, 
even  though  the  eastern  stations  are 
in  direct  line  with  all  large  Chicago 
stations.  On  account  of  the  fact  that 
this  set  uses  a  loop,  it  is  usually  easily 
possible  to  separate  stations  of  only  a 
few  meters  apart,  providing  they  are 
located  at  slightly  different  points  of 
the  compass.  Quite  frequently  it  has 
been  found  that  a  powerful  station 
remotely  situated  can  be  tuned  in  past 
a  local  station  about  the  same  power, 
if  a  distant  station  is  favored,  by  adjust- 
ing the  loop. 

Do  not  write  in  asking  if  this  set  will 
operate  on  an  aerial.  The  loop  has 
been  deliberately  used  so  as  to  make  the 
set  just  that  much  more  selective,  and 
to  work  it  successfully,  we  have  provided 
it  with  plenty  of  radio  frequency  am- 
plification. 

If  you  operate  it  on  an  aerial  you  will 
bring  in  more  volume,  to  be  sure,  but 
you  will  also  bring  in  a  lot  of  noise 
which  will  be  amplified  by  the  radio 
frequency  stages,  and  you  will  lose 
much  of  the  selectivity  which  is  one 
of  the  great  features  of  a  successful 
super-heterodyne. 


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The  Magazine  of  the  Hour        67 

elTungar 

batteries 


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The  Tungar  is  a  G-E 
product,  developed  In 
the  great  Research 
Laboratories  of  Gen- 
eral Electric. 

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terminals.  Slip  the  wire  into  one  and  charge 
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the  second  to  charge  your  radio  "B"  bat- 
tery, 24  to  96  volt  size.  Or  the  third  will 
charge  a  6  volt  "A"  battery  or  6  to  12  volt 
auto  battery. 

Just  clip  on  the  Tungar,  and  plug  it  into  any 
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§ 


The  bloodhound,  remarkable  for 
the  acuteness  of  its  smell, 
jriek   up   a   scent   and  follow 
trail  when  all  else  fails. 


* 


-never  before  thought  possible: 


With  the  extreme  acuteness  of  the  bloodhound's  scent, 
the  Model  L-2  Ultradyne  detects  the  faintest  broad- 
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— regenerates  and  makes  them  audible  on  the  loud 
speaker. 

It's  here,  where  the  development  of  other  super-radio 
receivers  has  halted;  the  Ultradyne  forges  ahead. 
The  unusual  sensitivity  of  the  Model  L-2  Ultradyne 
is  due  to  the  successful  application  of  regeneration,  to 
the  famous  Modulation  System  of  radio  reception, 
recently  perfected  by  R.  E.  Lacault,  E.E.,  A.M.I.R.E., 
Chief  Engineer  of  this  Company  and  formerly  Radio 
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search Laboratories. 

It's  this  development,  an  exclusive  feature  of  the 
Model  L-2  Ultradyne,  that  makes  it  possible  to  receive 
greater  distance  on  the  loud  speaker. 

In  addition  the  Ultradyne  is  the  most  selective  receiver 
known.  Regardless  of  close  similarity  in  wavelength, 
it  selects  any  station  within  range — brings  in  broad- 
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Everything  that  the  Model  L-2  Ultradyne  means  in 
actual  results  and  genuine  satisfaction,  you  will  ap- 
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*     Tested  and  Approved  by  RADIO  AGE     * 


The  Magazine  of  the  Hour 

Don't  Always  Blame 
the  Hookup 

{Continued  from  page  16) 

way  that  the  condensers  are  overheated. 
Fixed  condensers  are  insulated  with 
paraffin,  and  when  they  are  heated 
above  the  melting  point  of  paraffin  the 
"gravy"  will  run  out  and  it  is  likely 
that  the  condenser  will  be  ruined. 
Attach  solder  lugs  to  the  condensers 
by  screws  and  then  connect  the  wires 
to  the  solder  lugs  by  a  quick  deft  touch 
of  a  very  hot  iron  that  will  cause  as  little 
heating  as  possible.  Don't  lay  your 
iron  on  the  condenser  for  half  an  hour 
while  the  paraffin  bubbles  and  oozes 
out   of  the   insulation. 

Last  week  I  took  out  six  fixed  con- 
densers from  a  set  that  were  shorted  by 
soldering,  and  as  usual  the  trouble  was 
charged  up  to  the  hookup. 

Even  the  best  of  manufacturers  are 
not  infallible  in  spite  of  the  precautions 
taken  in  inspecting  their  product.  Every 
once  in  a  while  a  part  will  slip  through 
the  shop  that  is  defective.  Just  because 
a  part  bears  the  insignia  of  a  high  grade 
product  it  does  not  mean  that  all  of  the 
"bugs"  are  out  oHt.  The  only  insurance 
is  to  test  it  out  before  it  is  installed  in 
the  set,  and  for  this  reason  it  is  always 
best  to  rig  up  the  circuit  experimentally 
before  dolling  it  all  up  and  putting  it 
into  a  fancy  cabinet.  If  anything  proves 
wrong  when  the  parts  are  laid  out  on 
the  table  it  can  be  discovered  and 
remedied  before  we  have  put  in  a  lot 
of  work  on  the  final  assembly.  Just 
as  an  example  of  how  faults  may  develop 
in  apparatus  I  recently  took  an  $8.00 
transformer  apart  only  to  find  that  the 
trouble  was  caused  by  a  cockroach  which 
had  crawled  under  the  terminal  board 
and  then  had  calmly  laid  down  in  its 
long  last  sleep.  This  was  a  "bug"  in 
every  sense  of  the  word. 

Thin  Wire  is  Delicate 

TTEADSETS  and  audio  frequency 
-*--*-  transformers  are  wound  with  very 
fine  wire — finer  than  a  hair  in  most 
transformers.  Very  frequently  a  jar 
in  shipping,  or  roughly  handling  in  the 
store  may  cause  the  wire  to  break  near 
the  terminals  thus  opening  the  circuit. 
Transformers  and  headsets  should  always 
be  tested  for  open  circuits,  and  many 
variometers  are  not  above  suspicion  in 
this  respect.  Inspect  all  sliding  rotor 
contacts  on  condenser  shafts,  coupler 
rotors,  etc. 

Next  to  soldering  troubles  I  have 
experienced  more  grief  with  shellaced 
coils  than  any  other  part  of  the  circuit. 
The  average  amateur  who  has  had  a 
smattering  of  electrical  work  winds  his 
coils  according  to  specifications  and  then 
completes  the  job  by  giving  the  coil  a 
good  heavy  coat  of  shellac  varnish. 
Nothing  could  possibly  be  worse.  The 
shellac  has  an  exceedingly  high  electro- 
static coefficient  and  increases  the  dis- 
tributed capacity  of  the  coil  by  at  least 
one  hundred  times.  After  painting 
with  shellac  we  have  a  condenser  rather 
than  an  inductance.  Paraffin  is  nearly 
as  bad  and  should  be  avoided  except 
with     spiderweb     or     honeycomb     coils 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour         69 


where  insulation  capacity  has  little  effect. 
If  the  winding  must  be  doped,  use  some 
well  known  brand  of  anti-capacity 
varnish  or  else  a  stiff  solution  of  celluloid 
dissolved  in  banana  oil. 

Now  we  come  to  the  cheap  "molded 
mud"  tube  sockets,  the  primal  curse  of 
radio.  One  of  these  lie  sockets  will 
waste  more  energy  than  can  be  supplied 
by  ten  aerials.  There  are  only  three 
materials  suitable  for  tube  sockets — 
bakelite,  porcelain  and  hard  rubber  With 
the  exception  of  the  porcelain,  all  of 
the  materials  are  rather  expensive  and 
therefore  all  sockets  except  the  porcelain 
types  are  certain  to  be  rather  high 
priced.  A  few  makers  produce  cheap 
bakelite  sockets  by  making  the  walls 
about  one  sixteenth  inch  thick  and  by 
hollowing  out  all  around  the  base  to  save 
material.  Such  tube  sockets  have  the 
proper  insulation  value  all  right  but  are 
so  weak  mechanically  that  they  are 
likely  to  crack  out  of  the  notch  and 
allow  your  tube  to  shoot  up  to  the  ceiling. 
I  broke  two  $5.00  tubes  in  this  way 
before  I  decided  to  economize  in  other 
directions  than  on  the  sockets. 

And  Now  the  Batteries 

REVERSED  battery  polarities  are 
another  cause  of  premature  gray 
hair.  Please  remember  that  the  positive 
"B"  battery  connection  (  +  B)  should 
always  go  toward  the  plate  (P)  of  the 
tube  in  any  circuit.  The  (  +  B)  may 
reach  the  plate  (P)  directly  or  else 
indirectly  through  other  parts  of  the 
circuit,  but  the  negative  "B"  (  — B) 
should  never  be  connected  in  this 
way.  Follow  your  circuit  diagram  to 
the  bitter  end  in  regard  to  polarities. 
As  a  general  rule,  the  filament  rheostat 
should  be  placed  in  the  negative  "A" 
battery  line  (—A  or  — F).  The  positive 
"A"  (+A)  should  go  straight  to  the  (+) 
or  (+F)  post  of  the  tube  socket,  and  this 
applies  both  to  detector  and  to  amplifier 
circuits.  In  making  such  connections 
remember  that  the  sign  (  +  )  means 
"positive"  and  that  (— )  means  "nega- 
tive." Again,  it  is  sometimes  customary 
to  indicate  polarities  by  colors  and  in  this 
case  RED  indicates  the  positive  pole 
while    BLUE    or    black,    the  negative. 


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the  evidence 

Dunbar.  West  Va. 
Ferbend  Electric  Co. 
Qcntlcmen:  1  bouKh<  vour  WaveTraf 


aiceofielef 

O-f     of    GUI 


aphsl 


■swhic 


Mailed  ii  .n  our  fivc-mbe  Fada  Neutro- 
dvne  set  we  have  not  heard  any  more 
telegraphers— we  lei  'cm  in  lomcumci 
to  show  our  friends  hou.  caiy  it  is  to 
kick  Vm  out  with  the  Wove  Trap.  I 
:aSct«.i[hou(aFcrbend 


Wav, 


(Signed)    H.Er 


Farragut,  Iowa. 
Ferbend  Electric  Co, 

Dear  Sin:  1  set  my  radio  where 
Havana.  Cuba,  should  come  in  but  re- 
ceived only  a  jumble  of  K.  F.  N.  F.. 
W.O.R.  and  W.LA.C,  I  (hen  tuned 
in  with  the  Trap  and  had  Havana  for 


uhle    lib 


lha< 


alt 


:cd   five 


(Signed)   W.T.Cox. 


addi 

Si.. 


ndid  opinion  there  is  r 

■■inH    Set   complete   witt 

an  of  the  Ferbend  Wa- 

(Signed)    E.W.  Stcv< 


FERBEND  ELECTRIC  CO. 
16   E.  South  Water  St.,  Chicago, 
Gentlemen:  Please  send  me: 
(-I  WAVE  TRAP.    Send  post 
LJ  (check,  M.  O.. 


t  the 
l"rap. 

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Fidelity 


Just  as  the  rare  old  violin  expresses 
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The  Magazine  of  the  Hour 

"The  Sleuths  of  Honeymoon 
Camp" 

( Continued  from  page  30) 
created  by  a  very  small  current  operating 
somewhat  like  a  pilot  light  in  a  water- 
tank  heater.  The  killing  of  this  magnet 
breaks  the  circuit,  and  this  in  turn  closes 
a  larger  circuit  and  thereby  throws  over 
the  receiving  switch.  With  the  lapse  of 
the  ether  wave,  the  dead  magnet  becomes 
alive  again,  and  the  action  is  reversed." 

"How  does  the  burglar  alarm  work?" 
asked  Carl,  who  had  not  been  taken  into 
confidence  regarding  the  invention. 

"No  doubt  Ray  has  got  his  rights 
safely  protected  by  this  time,  so  I  suppose  it 
is  all  right  for  me  to  uncover  his  secret 
to    his    personal   friends,"   Billy  replied. 

"Several  months  ago,  you  know,  their 
place  was  broken  into  by  burglars,  and 
Ray  contrived  a  burglar  alarm  in  con- 
junction with  his  automatic  switch 
operating  device.  With  the  opening  of 
any  door  or  window  in  the  house,  another 
current  is  broken  and  a  magnet  killed, 
thereby  serving  to  throw  over  the  sending 
switch  and  broadcast  an  alarm  to  the 
amateur  world.  But  he  really  did  not 
regard  this  invention  seriously;  it  was 
contrived  more  as  a  plaything  than 
anything  else.  I  doubt  if  he  made  any 
actual  experiment  with  it  among  radio 
amateurs.  But  it  evidently  does  the 
work,  and  no  doubt  many  amateurs 
right  now  are  wondering  what  is  the 
meaning  of  that  stuff  we  just  listened  to." 

"It's  simply  an  automatic  broadcaster, 
isn't  it?"  Jerry  inquired. 

"Sure.  I  bet  I  can  hold  a  ghostly 
conversation  with  those  two  burglars 
and  maybe  scare  them  nearly  to  death. 
Meanwhile  the  switches  there  will  work 
back  and  forth  automatically  with  our 
voices.  I  happen  to  know  that  Ray  keeps 
his  instrument  tuned  up  to  162  meters, 
so  there's  no  reason  why  the  device 
shouldn't  work  to  perfection.  Now 
listen,  and  we  may  have  some  fun  with 
them.  Maybe  we  can  scare  them  away 
without  taking  anything  with  them.  If 
I  can't  scare  them  away,  or  afflict  them 
with  some  sort  of  radio  paralysis,  I'll 
try  to  get  word  to  the  police.  Be  careful ; 
don't  laugh  or  make  any  noise.  Some- 
thing funny  may  happen.  Quiet  now; 
here  they  are  again." 

The  Voices  Again 
iif^EE,   THIS  is   some   find,"   said  a 

^J  heavy  voice  in  the  loud  speaker. 
"All  this  silverware  is  solid,  and  this 
diamond  necklace  will  sure  bring  several 
hundred  dollars.  And  here's  a  pair  of 
silver  mounted  opera  glasses  and  a  solid 
silver  water  pitcher.  Say,  Sam,  it  was 
hard  work  breaking  open  the  safe,  but  it 
was  worth  the  trouble,  wasn't  it?" 

"I'll  say  so,"  was  "Sam's"  reply. 
"But  don't  talk  so  much.  No  use  hangin' 
around  here  any  longer.  Let's  dump  all 
this  stuff  in  the  bags  and  hustle  out.  No 
tellin'  when  some  of  these  foks'lll  come 
in  on  us." 

"Aw,  no  danger  o'  that.  They're  gone 
for  a  week  or  two.  We  could  go  to  bed  here 
and  sleep  till  3  o'clock  in  the  morning." 

"Yes,"  returned  the  other  with  sar- 
casm; "you  can  set  the  alarm  and  have 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour        71 


your  doze,  but   I'm  for  makin'  my  get- 
away now." 

"Aw,  I  was  only  kiddin',"  guffawed 
the  sleep  suggester.  "But  there's  no 
great  rush.  Let's  see  what  else  we  can 
find." 

"All  the  valu'bles  were  in  this  safe," 
insisted  the  alarm-clock  arguer.  "That's 
what  they  keep  it  for.  When  we've 
cleaned  that  out,  we're  through." 

"Yes,  it's  father's  home,"  cried  Alice, 
with  a  picture  of  two  rough  characters  in 
her  mind.  "He  put  that  safe  in  after  the 
other  robbery.  It's  right  near  the  radio. 
I  recognize  all  those  things  they  wers 
talking  about.  Oh,  dear  me!  Let'e 
jump  right  into  your  machine  and  rus<4 
back  and  get  the  police." 

Billy  laughed,  in  spite  of  the  gravity  of 
the  situation. 

"No,  we'd  never  get  back  in  time, 
unless  they  should  set  the  alarm  clock 
and  go  to  bed,"  he  objected.  "Besides, 
I've  taken  one  of  the  rear  wheels  off  and 
Jerry's  sedan  is  on  the  blink.  Just  be 
patient,  and  maybe  I  can  do  something 
with  them.  I'm  going  to  throw  over 
the  transmitting  switch.  You  may  spoil 
the  whole  thing  if  you  utter  a  sound." 

He  threw  over  the  switch  and  called 
into  the  microphone:  "Hands  up,  or 
I'll  shoot!" 

[To  be  concluded  in 
April  RADIO  AGE] 

A  Novel  Ultra-Audion 

( Continued  from  page  42) 
(TR)  is  shown  only  in  the  schematic 
diagram  Fig.  2  and  is  connected  into  the 
ground  circuit.  It  is  shunted  by  the 
switch  (S),  so  that  when  we  wish  to 
receive  instead  of  send,  we  can  short- 
circuit  the  transmitter  by  means  of  the 
switch.  This  can  be  built  into  the  set 
by  using  a  regular  microphone,  or  else 
one  of  the  Skinderviken  microphone 
buttons  which  can  be  procured  at  about 
SI. 00.  Under  proper  conditions  this 
outfit  can  transmit  about  five  miles  with 
90  to  120  volts  on  the  plate  of  the  first 
detector  tube  (Tl).  This  should  be  a 
UV-201A  or  preferably  a  five  watt  tube 
such  as  the  UV-202,  but  good  results 
will  be  obtained  with  the  former  tube. 

The  set  is  tuned  to  wavelength  when 
transmitting  by  the  condenser  (C)  just 
as  when  receiving.  The  tube  is  turned 
up  until  oscillation  is  obtained,  the 
switch  (S)  is  opened,  and  then  we  can 
transmit  when  speaking  into  (TR).  One 
night  while  fussing  around  with  this  out- 
fit, it  was  set  up  in  the  kitchen  while 
another  receiver  was  tuned  in  on  it  from 
the  front  living  room  about  30  feet  away. 
Never  thinking  that  it  would  go  beyond 
the  walls  of  the  building,  I  was  greatly 
surprised  to  discover  on  the  following 
morning  that  my  confidential  conversa- 
tions had  been  heard  all  over  town.  If 
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If  it  were  permitted  by  law,  that  is 
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Low  power  sets  of  this  sort  would  not 
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Competition  Narrows  in  Radio 
Age  Contest 

.  .;       (Continued  from  page  46) 
But  the  biggest  "hit"  of  them  all  was 
the  radio.     The  Art  Linick  of  the  radio 
is  the  comedian  we  all  know.     He  and 
his   twenty-eight    radio    numbers. 

Did  you  ever  hear  him  sing  "Previous?" 


Votes  Growing  Heavy 

T3Y  FAR  the  heaviest  vote  cast  to 
■*-*  date  was  during  the  thirty-day 
period  from  December  16  to  January  15. 
In  referring  to  the  "Standing  to  January 
15"  several  notable  changes  will  be  found, 
the  meteoric  rise  of  Art  Linick  from  six- 
teenth to  fifth  place  being  most  spectacu- 
lar. His  name  was  not  even  tabulated 
in  the  January  issue  of  RADIO  AGE. 
He  and  Bert  Davis  are  closely  crowding 
the  leaders  who  had  apparently  held  a 
safe  berth  for  some  time  past. 

While  Harry  M.  Snodgrass  and  Hired 
Hand  have  also  strengthened  their 
positions,  it  will  also  be  noted  that  three 
new  names  appear  upon  the  scene  from 
far  down  the  scale  into  what  we  call  the 
first  division. 

The  major  contest  is  almost  over.  As 
this  issue  of  RADIO  AGE  goes  to  press, 
there  remain  but  three  of  the  twevle 
months  in  which  to  name  your  candidate. 
The  contest  will  absolutely  end  at  mid- 
night, June  5. 

We  have  tried  to  be  fair,  as  we  have  no 
favorites.  It  is  in  your  hands  to  see  that 
your  candidate  carries  off  the  palm,  or 
we  should  say  "shield"  of  victory.  If 
his  name  does  not  appear  in  first  division, 
there  are  still  three  months  left  to  put 
your  choice  in  the  lead. 

Possibly  some  of  the  braodcasting  sta- 
tions will  be  kind  enough  to  call  the 
attention  of  their  audiences  to  this  con- 
test. Anyhow,  here's  hoping,  and  may 
the  best  man  win! 


"The  Mystery  Man"  of 
Station  WEEI 

(Continued  from  page  38) 

More  than  anything  else,  "Whit"  is 
striving  to  make  WEEI  a  station  of 
personality.  He  wants  people  to  feel 
that  it  is  a  homelike,  friendly  affair,  and 
not  something  remote.  With  his  genial, 
drawling  voice,  it  should  not  be  a  hard 
task. 

No  article  about  WEEI  would  be 
complete  without  mentioning  "Bob" 
Emery,  the  lovable,  congenial  "Big 
Brother."  "Bob"  came  to  WEEI  from 
Amrad,  WGI,  and  is  chief  announcer. 
He  is  bound  to  win  a  popularity  contest 
one  of  these  days.  He  has  a  perfect  radio 
voice,  can  sing,  play  the  piano  and  the 
ukelele — and  a  dozen  different  things. 
His  original  "Big  Brother"  club  has  an 
enrollment  of  7,500  youngsters  and  the 
little  tots. 

But  that's  another  story! 


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, 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour        73 


The  Girl  Who  Conquered 
The  Radio  Bores! 

(  Continued  from  page  33) 
thrilled  jazz-loving  multitudes  by  every 
known  means  of  sound  conveyance! 
Gracing  the  stage,  thousands  know  her  as 
an  unassuming  girl  who  could  knock  the 
Van  and  Schenck  out  of  those  eighty- 
eight  keys  absolutely  unassisted! 

And  her  pianola  rolls?  Well,  thousands 
of  American  homes  derive  the  benefits  of 
her  artistry  through  the  application  of  a 
little  foot  power. 

BUT  the  Hudson  vapors  that  enwrap 
the  broadcasting  towers  of  WEAF 
must  await  Vee's  arrival  on  the  air  each 
Sunday  evening  with  no  small  degree  of 
joyous  expectation.  Indeed,  happy  as 
they  are  to  hear  her,  they  in  no  way  near 
the  keen  enthusiasm  of  VVEAF's  six  mil- 
lion potential  radio  fans! 

Applause  cards  are  nice  little  things 
and  all  that — very  easy  to  send — and  Vee 
gets  loads  of  them.  But  when  your 
thankful  listeners  bespeak  their  gratitude 
with  dinner  invitations,  aye,  verily,  'tis 
gratitude  indeed!  Applesauce  on  the 
table  is  worth  two  applause  cards  in  the 
mails,  any  radio  artist  will  agree. 

Vee  is  known  in  the  inner  circles  of 
radio  life  as  the  girl  with  the  dinner  in- 
vitations. Somebody  up  in  Rhode  Island 
started  it — you  know,  friends  of  the 
family  and  that  sort  of  thing — and  this 
feeding-Vee  fad  has  spread  to  wherever 
WEAF  is  heard. 


Low  Loss  Tuners 

That  Give  Results     $£, 


Made  in  amateur,  and  broadcast 
types.  Price  $7.00.  A  post  card 
will  bring  it  to  you.  We  pay  post- 
age and  insurance.  Descriptive 
literature  and  hookup  sent  free  on 
request. 

DAVENPORT  RADIO 
LABORATORIES 

Davenport,  -  Iowa 

AUDIO  AMPLIFIER 

Tremendous       undistorted 
volume.         Trellco     Audio 
Amplifiers     positively  _  in- 
creases three  or  four  times 
the  volume  of  any  tube  or 
crystal     set.       With     this 
device  you  can  reach  out 
and  bring  in  those  distant 
stations    loud     and     cear. 
Money  back  gu£n-antee.    As 
J    illustrated,  including  tube. 
S7.00  postpaid  in  U.  S- 
TRELLCOTT  CO. 
2118  W.  Hale  Ave.  Louisville,      Ky. 


KUMON-ROSS 

Sells  only  Guaranteed 
'    Radio  Apparatus. 

:  Send  for  discounts. 

123 yt  Madison  St.  jChicago 


NOT  a  Copper 
Aerial 


* 


Jiffy  Ribbon  Antenna  is  NOT  a  copper  aerial,  but  is  made  of  highest 
grade  steel  with  a  special  plating  that  makes  it  absolutely  immune  to 
corrosion  or  oxidization.  It  has  tremendous  strength  and  is  guaranteed 
not  to   snap,   kink   or   curl. 

Jiffy  Ribbon  Antenna  stays  bright,  clean  and  efficient  month  after  month 
— in   all   kinds   of  weather. 


RIBBON 

ANTENNA. 

Gives  you  longer  range,  greater  volume 
and  far  more  pleasure,  service  and 
satisfaction  from  your  set.  Kndorsed 
by  thousands  of  users  everywhere.  Here 
is  the  non-copper  ribbon  aerial  that 
will  make  your  set  100%  efficient. 


Full   100  feet  complete  with  two  insulators, 
Ready  for  installation 


$150 


//  Your  Dealer  Cannot  Supply 
You,  Order  Direct  — TODAY! 


Apex  Stamping  Company, 
Dept.  42,  Riverdale,  111. 

Send  me ...Jiffy  Ribbon  Antenna,      I  agree  to  pay 

postman  $1.50  each,  plus  few  pennies  postage. 

Name _ 

Address 


HERCULES 

AERIAL  MAST 


20  Ft.  Mast  $10 

40  Ft.  Mast  $25 

GO  Ft.  Mast  $45 
All   steel    construction.    Com- 
plete   with    guy    wires       and 
masthead     pulley.     We     pay 
freight. 

s.  w.  hull  &  CO. 

Dept.  1-4,  2048  E  79th  St. 
CLEVELAND,  O. 


Write  for 

literature 

and 

FREE 

Blueprint 


CABINETS 

If  you  are  interested  in  a 
rachocabinet  in  which  ia 
combined  both  beauty  and 
practicability,  just  write 

LAKESIDE  SUPPLY  CO, 

Dept.  R 

73  West  Van   Burnt   St. 

CHICAGO,  ILL. 

Telephone,  Harrison  3840 


Mailing  Lists 

Will  help  you  increase  sales) 

|  Send  for  FREE  catalog  Bivine  counts 
and  prices  on  thousands  of  classified 
names  of  your  best  prospective  custom- 
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uals. Professions,  Business  Concerns. 

99%^ndte.£fd5(ieach 


Neutrodyne   Hunchbacks 

Change  that  Neut,  or  build  instead  of  a  Neat,  the  Kladag 
Coast  To  Coast  Circuit.  Same  panel,  same  layout  as 
Neut — fewer  parts.  Selective  with  deep,  resonant 
volume  Not  obtainable  elsewhere.  One  different  part, 
22  feet  gold  buswire.  lithographed  print,  complete,  sim- 
ple instructions — prepaid  anywhere,  $5.00.  Nothing  else 
to  buy.  Details.  10c.  48  page  parts  catalog,  10c. 
Stamps  accepted  same  as  cash. 

Kladag  Radio  Laboratories,  Kent,   O. 


74         RADIO   AGE  for  March,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA 

KDPM 

KDPT 

KDYL 

KDYM 

KDYQ 

KDZB 

KDZE 

KDZI 

KFAD 

KFAE 

KFAF 

KFAJ 

KFAR 

KFAU 

KFAW 

KFBB 

KFBC 

KFBG 

KFBK 

KFBL 

KFBU 

KFCB 

KFCC 

KFCF 

KFCL 

KFCP 

KFCV 

KFCZ 

KFDD 

KFDH 

KFDJ 

KFDM 

KFDX 

KFDY 

KFDZ 

KFEC 

KFEK 

KFEL 

KFEQ 

KFER 

KFEY 

KFFP 

KFFR 

KFFV 

KFFY 

KFGB 

KFCC 

KFGD 

KFGH 

KFGQ 

KFGX 

KFHA 

KFHH 

KFHJ 

fCFHL 

KFHR 

KFI 

KFIF 

KFIO 

KFIQ 

KFIU 

KF1X 

KFIZ 

KFJB 

KFJF 

KFJI 

KFJK 

KFJL 

KFJM 

KFJR 

KFJX 

KFJY 

KFJZ 

KFKA 

KFKB 

KFKQ 

KFKU 

KFKV 

KFKX 

KFLA 

KFLB 

KFLD 

KFLE 

KFLQ 

KFLR 

KFLU 

KFLV 

KFLX 

KFLZ 

KFMB 

KFMQ 

KFMR 

KFMT 

KFMW 

KFMX 

KFNF 

KFNG 

KFNJ 

KFNL 

KFNV 

KFNY 

KFNZ 

KFOA 

KFOC 

KFOD 

KFOJ 

KFOL 

KFON 

KFOO 

KFOP 

KFOR 

KFOT 

KFOU 

KFOX 

KFOY 

KFOZ 

KFPB 

KFPG 

KFPH 

KFPL 

KFPM 

KFPP 

KFPR 

KFPT 

KFPV 

KFPW 

KFPX 

KFPY 

KFOA 

KFQB 

KFQC 

KFQD 

KFQE 

KFQG 

KFQH 

KFQL 

KFQM 

KFQN 


Wefltlnghouee  Electric  &  Mfg.  Co East  Pittsburgh  309 

Westinghouse  Electric  &  Mfg.  Co Cleveland,  Ohio  270 

Southern  Electrical  Co San  Diego.  Calif.  244 

Newbouse  Hotel Bait  Lake  City,  Utah  250 

Savoy  Theatre San  Diego,  Calif.  280 

Oregon   Institute  of   Technology Portland,  Oreg.  360 

Frank  E.  Siefert Bakersfield,  Calif.  240 

Rhodes  Department  Store Seattle,  "Wash.  270 

Electric  Supply  Co Wenatchee,  TV  ash.  360 

McArthur  Bros.  Mercantile  Co Phoenix,  Ariz.  360 

State  College  of  Washington Pullman.  Wash.  330 

Western   Radio   Corporation ; Denver,  Colo.  278 

University  of  Colorado Boulder,  Colo.  360 

Studio  Lighting  Service  Co.  (O.  K.  Olsen) Hollywood,  Calif.  280 

Boise  High  School Boise,  Idaho  270 

The  Radio  Den  (W.  B.  Ashford) Santa  Ana,  Calif.  280 

P.  A.  Buttrey  &  Co Havre.  Mont.  360 

W.  K.  Azbill San  Diego,  Calif.  278 

First  Presbyterian  Church Tacoma.  "Wash.  250 

Kimball-Upson  Co .Sacramento,  Calif.  283 

Leese  Bros Everett.  "Wash.  224 

The  Cathedral Laramie,  Wyo.  283 

Nielson  Radio  Supply  Co Phoenix,  Ariz.  238 

The   First    Congregational   Church Helens.    Mont.  248 

Frank  A.  Moore Walla  Walla.  Wash.  256 

Leslie  E.  Rice Los  Angeles.  Cal.  236 

Ralph   W.    Flygare Ogden,  Utah  360 

Fred   Mahaffey,   Jr Houston,  Texas  360 

Omaha  Central  High  School Omaha,  Nebr.  258 

St.  Michaels  Cathedral Boise.  Idaho  252 

University  of  Arizona Tuscon,  Ariz.  368 

Oregon  Agricultural  College Corvallis,  Oreg.  254 

Magnolia    Petroleum    Co Beaumont.    Tex.  315 

First  Baptist  Church Shreveport.  La.  360 

South  Dakota  State  College Brookings,  S.  Dak.  360 

Harry  O.  Iverson Minneapolis.  Minn.  231 

Meier  &  Frank  Co Portland,  Oreg.  248 

Augsbury    Seminary Minneapolis,    Minn.  261 

Winner  Radio  Corp Denver.  Colo.  254 

J.  L.  Scroggin Oak,  Nebr.  268 

Auto  Electric  Service  Co Fort  Dodge.  Iowa  231 

Bunker  Hill  &  Sullivan  Mining  and  Concentrating  Co Kellogg,  Idaho  360 

First  Baptist  Church Moberly,  Mo.  266 

Nevada  State  Journal   (Jim  Kirk) Sparks,  Nev.  226 

Graceland   College Lamoni.  Iowa  280 

Pincus     &     Murphey     Music     House Alexandria.     La.  275 

Heidbreder  Radio  Supply  Co Utica,  Neb.  224 

Louisiana  State  University Baton  Rouge.  La.  254 

Chickasha  Radio  &  Electric  Co Chickasha.  Okla.  248 

Leland  Stanford   University Stanford  University,  Calif.  273 

Crary  Hardware  Co Boone.  Iowa  226 

First  Presbyterian   Church Orange,  Tex.  250 

Western  State  College  of  Colorado Gunnison,  Colo.  252 

Ambrose  A.  McCue Neah  Bay.  Wash.  261 

Fallon  &  Co Santa  Barbara,  Calif.  360 

Penn     College Oskaloosa.     Iowa  240 

Star  Electric  &  Radio  Co Seattle,  Wash.  283 

E.  C.  Anthony.  Ine Los  Angeles,  Calif.  469 

Benson  Polytechnic  Institute Portland.  Oregon  248 

North  Central  High   School Spokane,  Wash.  252 

First  Methodiat   Church Yakima,  Wash.  242 

Alaska  Electric  Light  &  Power  Co Juneau.  Alaska  226 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints.  Independence,  Mo.  240 

Daily  Commonwealth  and  Oscar  A.  Huelsman Fon  Du  Lac.  Wis.  273 

Marshall  Electrical  Co Marshalltown ,  Iowa  248 

National  Radio  Manufacturing  Co Oklahoma  City,  Okla.  252 

Liberty  Theatre  (E.  E.  Marsh) Astoria.  Oreg.  252 

Delano  Radio  and  Electrio  Co Briatow.  Okla.  233 

Hardsacg  Manufacturing  Co Ottumwa.  Iowa  242 

University  of  North   Dakota Grand   Forks.   N.   Dak.  280 

Ashley  C.  Dixon  A  Son Stevensville,  Mont,  (near)  258 

Iowa  State  Teacher's  College Cedar  Falls.  Iowa  280 

Tunwall  Radio  Co Fort  Dodge.  Iowa  246 

Texas  National  Guard.  One  hundred  and  twelfth  Cavalry. Fort  Worth  Texas  254 

Colorado  State  Teachers  College Greeley.  Colo.  273 

Brinkley-Jones    Hospital  Aasociation Milford.  Kans.  286 

Radio  Laboratories  (Ben  H.  Woodruff) Conway,  Ark.  250 

University    of    Kansas Lawrence.    Kans.  275 

F.  F.  Gray Butte.  Mont.  283 

Westinghouse  Electric  &  Manufacturing  Co Hastings,  Nebr.  288 

Abner  R.  Willson Butte.  Mont.  283 

Signal  Electric  Manufacturing  Co Menominee.  Mich.  248 

Paul  E.  Greenlaw ." Franklinton.   La.  234 

National  Educational  Service Denver.  Colo.  268 

Bizzell Radio  Shop Little  Rock.  Ark.  261 

University  of  New  Mexico ' Albuquerque,  New  Mexico  254 

Rio  Grande  Radio  Supply  House San  Benito,  Texas  236 

Rev.  A.  T.  Frykman Rockford.  111.  229 

George  Roy  Clough Galveston.  Tex.  240 

Atlantic   Automobile    Co Atlantic,    la.  273 

Christian  Churches Little  Rock,  Ark.  254 

University  of   Arkansas Fayetteville.  Ark.  263 

Morningside  College Sioux  City,  Iowa  261 

Dr.  George  W.  Young Minneapolis.  Minn.  231 

M.    G.   Sateren Houghton,   Mich.  266 

Carleton  College Nortbfield.  Minn.  283 

Henry  Field  Seed  Co : Shenandoah , Iowa  266 

Wooten's    Radio   Shop Coldwater.  Miss.  254 

Central  Mo.  State  Teachers  College Warrensburg.  Mo.  234 

Radio  Broadcast  Ass'n Paso  Robles.  Calif.  240 

L.  A.  Drake  Battery  and  Radio  Supply  Shop Santa  Rosa,  Calif.  234 

Montana  Phonograph  Co Helena.  Montana  261 

Royal  Radio  Company Burlingame,  Calif.  231 

Rhodes  Department  Store Seattle  .Wash.  455 

First   Christian    Church Whittier,   Calif.  236 

Radio  Shop Wallace .  Idaho  224 

Moberly  High  School  Radio  Club Moberly.  Missouri  246 

Leslie   M.   Schafbush Marengo.   Iowa  234 

Echopbqne  Radio  Shop Long  Beach,  Calif.  234 

Latter  Day  Sainta  University Salt  Lake  City.  Utah  261 

Rohrer      Elec.       Co Marshfield       Ore.  240 

David  City  Tire  &  Electrio  Co David  City.  Nebraska  226 

College  Hill  Radio   Club Wichita.   Kansas  231 

Hommel  Mfg.  Co Richmond,  Calif.  254 

Board  of  Education.  Technical  High  School Omaha.  Nebraska  248 

Beacon  Radio  Service St.  Paul.  Minn.  226 

Leon  Hudson  Real  Estate  Co Fort  8mith.  Ark.  233 

Edwin    J.    Brown Seattle,    Wash.  224 

Garretsoo  and   Dennis Los   Angeles.  Calif.  238 

Harold  Chas.  Mailander Salt  Lake  City,  Utah  242 

C.   C.  Baiter Dublin.  Texas  242 

The  New  Furniture  Co Greenville,  Texas  242 

G.  &  G.  Radio  &  Electrio  Shop Olympia,  Washington  236 

Los  Angelea  Co.  Forestry  Dept Lea  Angeles    Calif.  231 

Cape     &     Johnson Salt     Lake     City,  Utah  268 

HeintS  &   Kohlnioos.  Inc San  Francisco.   Calif.  236 

St.  Johns  M.  E.  Church Carterville  Mo.  268 

First    Presbyterian    Church Pine    Bluff     Ark.  242 

Symons  Investment  Co Spokane.  Wash.  283 

The   Principle, .  .  ..  ... St.  Louis.  Mo.  264 

The  Searchlight  Publishing  Co Fort  Worth,  Tex.  221 

Kidd  Brothers  Radio  Shop Taft  'Calif.  258 

Cbovin  Supply  Co Anchorage.  Alaska'  207 

Dickenson-Henry  Radio  Laboratories Colorado  Springs  ,  Colo.  224 

Southern  Calif.  Radio  Aas'n Lo8  Angeles  ,  Calif.  226 

Radio    Service    Co Burlingame  .Calif.  231 

Oklahoma  Free  State  Fair  Aaan Muskogee.  Okla.  252 

Texas  Highway   Bulletin Austin,  Tex.  268 

Third  Baptist  Church .- Portland.  Ore!  283 


KFQP       G.   S.   Carson,  Jr Iowa   City,  la.  224 

KFQR       Walter  LaFayette  Ellis Oklahoma   City,    Okla.  250 

KFQT       Texas  National  Guard Denison,  Texas  252 

KFQU       W.  Riker Holy  City,  Calif.  234 

KFQV       Omaha  Grain  Exchange    (Portable) Omaha,  Nebr.  231 

KFQW      C.  F.  Knierim North  Bend,  Wash.  248 

KFQX      Alfred   M.    Hubbard Seattle,    Wash.  233 

KFQY       Farmers  State  Bank Belden.Neb.  273 

KFQZ       Taft  Radio  Co Hollywood,  Calif.  240 

KFRJ        Guy  Simmons.  Jr Conway  ,  Ark.  250 

KFRM      James   F.    Boland Fort   Sill.    Okla.  263 

KFRN        M.  Laurence  Short Hanford.  Calif.  224 

KFRO       Curtis   Printing   Co Ft.   Worth,    Tex.  246 

KFRU       Okmulgee  Dist.  Oil  and  Gas  Assn Bristow,  Okla.  381 

KFRW      United  Churched  of  Olympia Olympia.  Wash.  220 

KFRX       J.    Gordon    Klemgard Pullman.    Wash.  217 

KFRY  New  Mexico  Collegeof  Agriculture  and  Mechanic  Arts,    State  College,  N.  M.  266 

KFRZ       The  Electric  Sbop Hartington.  Neb.  222 

KFSG       Angelus  Temple Los  Angeles.  Calif.  278 

KFSY        The  Van  Blaricon  Co Helena, Mont.  2«1 

KFUJ        Hoppert  Plumbing  and  Heating  Co Breckenridge.  Minn.  242 

KFUL        Thomas  Goggan  &  Bros.  Music  Co Galveston.  Tex.  258 

KFUM       W.  D.  Corley Colorado  Springs.  Colo.  242 

KFUO       Concordia    Seminary St.    Louis.     Mo.  549 

KFUP       Fitzsimmons    General    Hospital Denver.    Col.  234 

KFU  Q       Julius  Brunton  and  Sons  Co San  Francisco.   Cal.  234 

KFUR"      H.  W.  Peery  and  C.  Redfield Ogden,  Utah  224 

KFUS        Louis    L.    Sherman Oakland.    Calif  233 

KFUT       University  of  Utah Salt  Lake   City,   Utah 

KFUU        Colburn  Radio  Labs San  Leandro.  Cal.  234 

KGB          Tacoma  Daily  Ledger Tacoma,  Wash.  252 

KGO          General  Electrio    Co Oakland.    Calif.  312 

KGU         Marion  A.  Mulrony Honolulu,  Hawaii,  Waikiki  Beach  360 

KGW         Portland  Morning  Oregonian Portland.  Oreg.  485 

KGY         St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy.  Wash.  258 

K.HJ           Times-Mirror    Co Los    Angeles,    Calif.  404 

KHQ          Louis    Wasmer Seattle,    Wash.  360 

KJQ           C.    O.   Gould Stockton,    Calif.  273 

KJR           Northwest  Radio  Sendee  Co Seattle.  Wash.  405 

KJS             Bible   Institute  of   Los   Angeles.   Inc Los  Angeles.   Calif.  252 

KLS            Warner  Brothers   Radio  Supplies   Co Oakland,   Calif.  360 

KLX          Tribune  Publishing  Co Oakland,  Calif.  509 

KLZ           Reynolds  Radio  Co :. .Denver,   Colo.  283 

KMJ           San  Joaquin  Light  &.  Power  Corp Fresno,  Calif.  248 

KMO         Love  Electrio  Co Tacoma,  Wash.  250 

KNT           Walter  Hemrich Kukah  Bay.  Alaska  263 

KNX          Los  Angeles  Evening  Express Los  Angeles.  Calif.  337 

KOA           General  Electric  Co Denver  Col.  323 

KOB  New  Mexico  College  of  Agriculture  &  Mechanic  Arts .  .  State  College.  N .  Mex.  348 

KOP          Detroit  Police  Department Detroit,  Mich.  286 

KPO           Hale  Bros San  Francisco.  Calif.  423 

KPPC        Pasadena    Presbyterian    Church Pasadena.    Cal.  229 

KQV          Doubleday-Hill  Electric  Co Pittsburgh.  Pa.  270 

KQW         Charles  D.  Herrold San  Jose,  Calif.  240 

KRE          V  C  Battery  &  Electric  Co Berkeley.  Calif.  275 

KSAC        Kansas  State  Agricultural  College Manhattan,  Kans.  341 

KSD          Post  Dispatch  (Pulitzer  Pub.  Co.) St.  Louis.  Mo.  549 

KTHS       New  Arlington  Hotel  Co Hot  Springs.  Ark.  375 

KTW         First  Presbyterian  Church Seattle,  Wash.  360 

KUO           Examiner  Printing  Co San  Francisco,  Calif.  246 

KWG         Portable  Wireless  Telephone  Co Stockton.  Calif.  360 

KWH         Los   Angeles  Examiner Los  Angeles.    Calif.  360 

KYQ         Electric    Shop Honolulu.    Hawaii  270 

KTW        Westinghouse  Electrio  &  Mfg.  Co Chicago.  111.  535 

KZM          Preston    D.    Allen Oakland.    Calif.  360 

WAAB      Valdemar   Jensen New    Orleans.    La.  268 

WAAC      Tulane  University New  Orleans.  La.  275 

WAAD      Ohio  Mechanics  Institute Cincinnati.  Ohio  248 

WAAF      Chicago  Daily  Drovers  Journal Chicago.  111.  286 

WAAM     I.  R.  Nelson  Co Newark,  N.J.  263 

WAAN       University  of  Missouri Columbia,   Mo.  254 

WAAW     Omaha  Grain  Exchange Omaha.    Nebr.  286 

WAB A       Lake  Forest  University Lake  Forest,  HI  227 

WABB      Harrisburg  8porting  Goods  Co Harrisburg.  Pa.  266 

WABD      Parker  High  School Dayton.  Ohio  283 

WABH      Lake  Shore  Tire  Co Sandusky,  Ohio  240 

WABI        Bangor  Railway  &  Electric  Co Bangor.  Me.  240 

WABL       Connecticut   Agricultural    College Storrs,    Conn.  283 

WABM     F.  A.  Doherty  Automotive  and  Radio  Equipment  Co Saginaw,  Mich.  254 

WABN      Ott  Radio.  Inc LaCrosse.  Wis.  244 

WABO       Lake  Avenue  Baptist  Church Rochester.  N.  Y.  283 

WABQ      Hnverford  College.  Radio  Club Haverford,  Pa.  261 

WABR      Scott  High  School.  N.  W.  B.  Foley Toledo.  Ohio  270 

WABU      Victor  Talking  Machine  Co Camden.  N.  J.  226 

WABW     College  of  Wooster Wooster.  Ohio  234 

WABX      Henry  B.  Joy Mt.  Clemens,  Mich.  270 

WABY      John  Magaldi.  Jr Philadelphia.  Pa.  242 

WABZ      Coliseum  Place  Baptist  Church New  Orleans.  La.  263 

WAHG      A.  H.  Grebe  i  Co Richmond  Hill.  N.Y.  315 

WBAA       Purdue  University W.    Lafayette.   Ind.  283 

WBAC      Clemson  Agric.  College Clemson  College,  S.  C.  331 

WBAH      The  Dayton  Co Minneapolis.  Minn.  417 

WBAN      Wireless  Phone  Corp Paterson,  N.  J.  244 

WBAO      James     Millikin     University Decatur,    ni.  360 

WBAP      Wortham-Carter  Publishing  Co.  (Star  Telegram) Fort  Worth.  Tex.  472 

WBAV      Erner  &  Hopkins  Co Columbus.  Ohio  293 

WBAX      John  H.  Stenger,  Jr Wilkes-Barre.  Pa.  254 

WBAY      Western  Electric  Co New  York.  N.  Y.  492 

WBBD       Barbey  Battery  Service Reading.  Pa.  234 

WBBG      Irving  Vermilya Mattapoisett,  Mass.  248 

WBBH      J.  Irving  Bell Port  Huron.  Mich.  246 

WBBL       Grace  Covenant  Presbyterian   Church Richmond.   Va.  283 

WBBM      H.    Leslie   Atlaas Chicago,  111.  226 

WBBN       Blake.  A.  B Wilmington.  N.  C.  275 

WBBP       Petoskey    High    School Petoskey,  Mich.  246 

WBBR      Peoples    Pulpit   Asso Rossville.   N.   Y.  273 

WBBS       First  Baptist  Church New   Orleans. La.  252 

WBBU      Jenks    Motor   Sales    Co Monmouth  .  111.  224 

WBBV      Johnstown  Radio  Co Johnstown,  Pa.  245 

WBBX      Ruffner     Junior     High     School Norfolk,  Va.  222 

WBBY      Washington  Light  Infantry  Co.  "B"  118th  Inf. Charleston.  S.  C.  268 

WBBZ      Noble  B.  Watson Indianapolis.  Ind.  227 

WBCN       Foster  &  McDonald Chicago.    111.  266 

WBDC      Baxter    Laundry    Co Grand    Rapids,    Mich.  256 

WBGA      Jones  Elec.  &  Radio  Mfg.  Co Baltimore,  Md.  254 

WBR          Pennsylvania  State  Police Butler,  Pa.  286 

WBRE      Baltimore      Radio      Exchange Wilkes      Barre,      Pa.  231 

WBS          D.  W.  May,  Inc Newark.  N.  J.  260 

WBT          Southern    Radio    Corp Charlotte,    N.    C.  275 

WBZ          Westinghouse     E.    4    M.    Co Springfield,    Mass.  333 

WCAD       St.  Lawrence  University Canton.  N.  Y.  280 

WCAE       Kaufmann  &  Baer  Co Pittsburgh.  Pa.  461 

WCAG      Clyde  R.  Randall New  Orleans.  La.  268 

WCAH      Entrekin   Electric   Co Columbus,  Ohio  286 

WCAJ       Nebraska  Wesleyan  University University  Place,  Nebr.  283 

WCAK,      Alfred  P.  Daniel Houston.  Texas  263 

WCAL        St.  Olaf  College Northfield.   Minn.  336 

WCAO      Sanders  &.  Stayman  Co Baltimore.  Md.  275 

WCAP       Chesapeake  &  Potomac  Telephone  Co Washington.  D.  C.  468 

WCAR      Alamo  Radio  Electric  Co San  Antonio.  Tex.  263 

WCAS        W.  H.  Dunwoody  Industrial  Instituto Minneapolis,  Minn.  280 

WCAT        State  College  ol  Mines Rapid  City. 8. Dak.  240 

WCAU      Durham   &   Co Philadelphia .  Pa.  286 

WCAV       J.  C.  Dice  Electric  Co Little  Rock.  Ark.  283 

WCAX      University   of    Vermont Burlington  .  Vt.  380 

WCAZ       Carthage    College Carthage  .  111.  246 

WCBA       Charles  W.  Heibachm Allentown,  Pa.  280 

WCBC     University  of  Michigan Ann  Arbor,  Mich.  280 

WCBD      Wilbur  G.  Voliva Zion.  111.  344 


RADIO  AGE  for  March,  1925 


And  now— 

Another  inventor  and  designer 
of   radio    apparatus    specifies 

FIfcKO-LEAK 

SCIENTIFICALLY     COR.  R.ECT 
VARIABLE      CR-ID        LEAK. 

its  calibrated 

by  hand — 

in  Megohms 


Al  Dealers 
$2.90  in  Canada 


Know  the  joy 
of  faultless  re- 
ception. Con- 
^.  trol  your  grid 
■?f>  action  with  Fil- 
•"JS^  '  Ko-Leak.  Clear 
"up  distortion;  increase 
volume;  get  stations  you 
never  heard  before.  Re- 
sistance read  in  megohms 
through  panel  peephole 
— or  baseboard  mount- 
ing. Resistance  element 
constant,  accurate.  Un- 
conditionally guaranteed. 
AtdealersorDept.RA325 


FIL-KO-LEAKS  are  specified  for  the 
Hoyt  System  of  Signal  Augmenta- 
tion by  the  inventor,  Francis  R. 
Hoyt.  We  have  a  limited  number  of 
blue  printed  copies  of  Mr.  Hoyt's 
original  laboratory  notes  on  this  new 
system  together  with  nine  circuit 
sketches,  which  will  be  sent  free  on 
receipt  of  four  cents  postage. 


DX  Instrument  Co.,  Harrisburg,  Pa. 


The  Greatest  Bargain 
Catalog  published.  Chock 
full  of  thousands  of  Radio  Bargains 
at  the  lowest  prices  to  be  found  any- 
where in  the  United  States. 
Parts,     Supplies,     Sets,     Parts    of 

Sets,     Latest    Circuits. 
Send  for  this  catalog  today. 

We  have  friends  in  every  city, 
town  and  hamlet.  Our  reputation  is 
our  bond.  No  red  tape.  Honest 
merchandise.  Goods  shipped  on  ap- 
proval. No  risk — satisfaction  or 
money  refunded.  No  arguments — No 
money  in  advance.  Ask  this  maga- 
zine about  us 
WHOLESALE  RADIO  SERVICE 

Dept.  E 
9  Church  St.,  New  York  City 


CLASSIFIED 
ADVERTISEMENTS 

RADIO  AGE  classified  advertisements 
have  paved  the  way  to  independent  in- 
comes. The  classified  rates  are  but  1 0 
cents  per  word  per  single  insertion.  Lib- 
eral discounts  allowed  on  3,  6  and  12-time 
insertions,  of  5,  15  and  30%  respectively. 
Cash  should  accompany  all  orders.  No 
ad  less  than  10  words  accepted. 


AGENTS  WANTED 


RADIO 
adve; 


We 


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sed  sets  and  parts  made  by  the  le 
cturers.  Widener  of  Kansas  City  ma 
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r  catalog,  and  discounts.  Name  your  cour 
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MANUFACTURER'S  AGENT 
trical  Jobbers,  Chicago  and  vi< 
additional  lines  carrying  volur 
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HELP  WANTED 


ind  SET  BUILDERS— We  need 
.  If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  III. 


MANUFACTURING  FACILITIES 


AN  OLD  AND  WELL  ESTABLISHED  MANUFACTUR- 
ING COMPANY  IN  THE  MIDDLE  WEST  WITH  LARGE 
WELL  EQUIPPED  PLANTS  AND  UNUSUAL  FINAN- 
CIAL RESOURCES,  DESIRING  TO  ENTER  THE  RADIO 
FIELD  WILL  CONSIDER  THE  MANUFACTURE  AND 
SALE  OF  RADIO  SETS  OR  DEVICES  OF  OUTSTAND- 
ING AND  UNUSUAL  MERIT  ON  A  ROYALTY  BASIS. 
ADDRESS  BOX  1A,  RADIO  AGE. 


RADIO 


A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  III. 


Standard  soderle 


Binding  post  attac 
dollar  bill.  Postpa 
New  York,   N.   Y. 


Thrc 
inst 

ucUo™ 

lopolitan 
s   include 

Phusiforme 
I.      F.   A.    M 

rs,  each  $5.50 
all,    Triopli,    1 

owTk  °' 

1(10 
dew 

Mfg 

VOLT    EDISON    TYPE    ' 

1.        Parts      and      plans 1 

,  2937  W.  Lake,  Chicago. 

B" 

BATTERY, 
plete,     $12. 5( 

knocked 
Lane 

FOR  SALE— 3  Pfanstiehl  tuni 
densers,    1     Bradleyometer,  2 
New.     Earl  Price,  Lodi,  Wis. 

ng 
Br 

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adleystats. 

veil  Con- 
All  goods 

RAD 

IO  CIRCUITS 

BLUEPRINTS— Make  your  own  set  from  proven 
original  and  up-to-the-minute  blueprints.  The  follow- 
ing are  merely  three  of  a  choice  of  almost  one  hundred 
different  types: 

HT-1-3— Five  tube  neutrodyne — 50c. 

FE-6 — Three-honeycomb  regenerative — 35c. 

D10-4 — Diode  single  circuit — 25c. 

All  three  of  above,  for  $1.00. 

These  tested  blueprints  are  all  made  up  in  easily 
read  circuit  drawings.  MIDLAND  PRODUCTS  COM- 
PANY, 1413  Hood  Ave.,  Chicago.  111.  Ask  for  our  com- 
plete list,  No.  R-31. 


RADIO   DEALERS 


DEALERS— Writ. 
Radio  Merchand 
Dept.  D,  1830  Wil 


illustrated  catalo 
ssiter-Manning  C 
,  Chicago,  III. 


STAMPS  AND  COINS 


I  Make  the  Best  CHOCOLATE  BARS 

Mints  and  Chewing  Gum.  Be  my  agent.  Every- 
bodywill  buyfromyou.  Write  today.  FreeSamples. 
MILTON  GORDON,      644  Jackson  St.,      Cincinnati,  Ohio 


Beg  Your  Pardon! 

Through  an  error  last  month,  the  cuts  show- 
ing wiring  of  circuits  contributed  by  Mr.  Ger- 
rill  and  Mr.  Hultman,  in  our  Pickups  Section, 
were  reversed.  We  are  sorry  this  happened  and 
trust  that  the  fans  have  suffered  no  incon- 
venience. 


158  Genuine  Foreign  Stamps.  Mexico  War  Issues. 
Venezuela,  Salvador  and  India  Service.  Guatemala, 
China,  etc.,  only  5c.  Finest  approval  sheets,  50  to 
60    per    cent.      Agents   Wanted.      Big_72-p.    Lists    Ft 


We     Bu 
Sta 


St, 


Established    20 
Dept.  152,  St.  Louis,  Mo. 


H 


WANTED 


WANTED— T« 
August,    Septe: 


Hollbrook,  Ariz 


bound.     Ad^ 


my     set     RADIO     AGE 
>ber,    November,    1923,    is 
ise  price.     Lloyd  C.  Hen 


WRITERS 


The  Magazine  of  the  Hour         75 

Now  you  can 

UNDERSTAND 

RADIO! 


Take    the    mystery    out    of    it 

build   and    repair   sets explain 

the     vacuum     tube  —  operate     a 
transmitter — be  a  radio  expert! 


1  VOLUME 
514  PAGES 

Leatheroid  Edition 

Compiled  by 

HARRY  F.  DART 

E.E. 

Formerly  with  the 
Western  Electric 
Co.,  and  U.  S. 
Army  Instructor 
of  Radio. 


Technically  Edited  by  F.  H.  Doane 
100,000  ALREADY  SOLD 

This  practical  and  authoritative  I.  C.  S.  Hand- 
book is  considered  one  of  the  biggest  bargains  in 
radio  today.  Over  100,000  homes  rely  on  the 
I.  C.  S.  Radio  Handbook  to  take  the  mystery  out 
of  radio.  Why  experiment  in  the  dark  when 
you  can  quickly  learn  the  things  that  insure  suc- 
cess? Hundreds  of  illustrations  and  diagrams 
explain  everything  so  you  can  get  the  most  out 
of  whatever  receiver  you  build  or  buy. 

It    contains:    Electrical    terms    and    cir- 
cuits,    antennas,     batteries,     generators 
and    motors,   electron    (vacuum)    tubes, 
many  receiving  hook-ups, radio  and  audio 
frequency    amplification,   broadcast   aad 
commercial    transmitters    and    receivers, 
wave  meters,  super-regeneration,  codes, 
license  rules.     Many  other  features. 
A  practical  book.     Written  and  edited  by  ex- 
perienced  engineers,   in   plain  language.      Some- 
thing useful  on  every  one  of  its  514  pages.     The 
authority   that  covers  every   phase   of   radio,   all 
under  one  cover   in  one  book   at  a  surprisingly 
small  cost.     Don't  spend  another  cent  for  parts, 
turn  a  dial  or  touch  a  tool  until  you  have  mailed 
$1.50  for  this  I.  C.  S.  Eadio  Handbook. 

Send  $1.50  at  once  and  get  this  514-page 
l.C.S.  Radio  Handbook — the  biggest  valae  in 
radio    today.      Money   back    it   not   satisfied. 

, TEAR  OUT   HERE j 

International  Correspondence  Schools 
Box  8784-C.  Scranton.  Penna. 
I  am  enclosing  $1.50.  Please  send  me—post- 
paid—the  514-page  l.C.S.  Radio  Handbook 
It  is  understood  that  if  I  am  not  entirely  satisfied 
1  may  return  this  book  within  Ave  days  and  you 
will  refund  my  money. 


Address "V""""' 

Check   Iters   D   ""d   enclose   $1    if   sou  wish    the 
cloth-hound  edition. 


NEW  WRITERS  WANTED — Articles,  stories,  poems, 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No.  bunk.)  NOT  A  CORRE- 
SPONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
azines. Send  self  addressed  envelope  for  list  of  100 
subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Los 
Angeles,  Calif. 

¥     Tested  and  Approved  by  RADIO  AGE     ¥ 


EVERYTHING  FOR  THE 

RADIO  HOOKUP  FAN 

Will  be  found  in  the 

RADIO  AGE  ANNUAL  for  1925. 

SEE  PAGE  80  for 

complete  details. 

Have    you    seen    the    32-page 

BLUEPRINT  SECTION 

In   the    NEW   RADIO   AGE 

ANNUAL? 


76         RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


WCBE  Uhalt  Radio  Co New  Orleans.  La.  263 

WCBF  Paul  J.  Miller Pittsburgh.  Pa.  236 

WCBG  Howard  S.  Williams  (Portable) Paseagoula.  Miss.  263 

WCBH  University     of     Miss Oxford,     Miss.  242 

WCBI  Nicoll.  Duncan  4  Rush Bemis.  Tennessee  240 

WCBJ  J.  C.  Maus Jennings,  Louisiana  244 

WCBK  E.  Richard  HalL St.  Petersburg,  Fla.  266 

WCBL  Northern  Radio  Mfg.  Co Houlton,  Me.  280 

WCBM  Charles  Swarz Baltimore.   Md.  229 

WCBN  James  P.  Boland Ft.  Beni.  Harrison.  Ind.  266 

WCBO  The  Radio  Shop.  Inc Memphis.  Tenn.  250 

WCBQ  First   Baptist   Church Nashville.   Tenn.  236 

WCBR  C.  H.  Messier Providence.  R.  I.  246 

WCBT  Clark  University,  Collegiate  Dept Worcester,  Mass.  238 

WCBU  Arnold  Wireless  Supply  Co Arnold.  Pa.  254 

WCBV  Tullahoma  Radio  Club Tullahoma.  Tenn.  252 

WCBW  George  P.  Rankin,  Jr.,  and  Maitland  Solomon Macon,  Ga.  226 

WCBX  Radio  Shop  of  Newark  (Herman  Lubinsky) Newark,  N.  J.  233 

WCBY  The  Forks  Electrical  Shop Buck  Hill  Falls.  Pa.  268 

WCBZ  Coppotelli  Bros.  Musio  House Chicago  Heights.  111.  248 

WCCO  Washburn-Crosby    Co Twin    Cities.    Minn.  416 

WCEE  Charles  E.   Erbstein,  Villa  Olivia near  Elgin,   III.  535 

WCK  Stix-Baer-FuUer  D.  G.  Co St.  Louis.  Mo.  275 

WCX  Free     Press Detroit,     Mich.  516 

WDAE  Tampa   Daily  Times Tampa.   Fla.  365 

WDAF  Kansas   City   Star Kansas   City,   Mo.  411 

WDAG  J.   Laurence  Martin Amarillo.  Tex.  263 

WDAH  Trinity  Methodist  Church   (South) El  Paso.  Tel.  268 

WDAR  Lit    Brothers Philadelphia.     Pa.  394 

WDAS  Samuel    A.    Waite Worcester,    Mass.  360 

WDAY  Radio    Equipment   Corp Fargo.    N.   Dak.  244 

WDBA  Fred     Ray Columbus.     Ga.  236 

WDBB  A.  H.  Waite  &  Co..  Ino Taunton.  Mass.  229 

WDBC  Kirk.    Johnson    &   Co Lancaster.    Pa.  258 

WDBD  Herman     Edwin     Burns Martinsburg.     W.     Va.  268 

WDBE  Gilham-Schoen  Elec.  Co Atlantic.  Ga.  278 

WDBF  Robert  G.  Phillips Young3town.  Ohio  315 

WDBH  C.  T.  Scherer  Co Worcester.  Mass.  268 

WDBI  Radio  Specialty  Co St.  Petersburg.  Fla.  226 

WDBJ  Richardson    Wayland   Electric    Corp Roanoke.    Va.  229 

WDBL  Wise.  Dept.  of  Markets. Stevens  Point.  Wis.  278 

WDBN  Electric  Light  &  Power  Co Bangor.  Me.  252 

WDBO  Rollins    College    Inc Winter    Park,    Fla.  240 

WDBP  Superior  State   Normal  School Superior.  Wis.  261 

WDBQ  Morton  Radio  Supply  Co Salem.  N.  J.  234 

WDBR  Tremont  Temple  Baptist  Church Boston.  Mass.  256 

WDBS  S.  M.  K.  Radio  Corp Dayton.  Ohio  283 

WDBT  Taylor's  Book  Store Hattiesburg.   Miss.  236 

WDBV  The  Strand  Theatre Fort  Wayne.  Ind.  258 

WDBW  The  Radio  Den Columbia.  Tenn.  268 

WDBX  Otto  Baur New  York.  N.  Y.  233 

WDBY  North    Shore    Congregational    Church Chicago,    III.  258 

WDBZ  Boy  Scouts,  City  Hall Kingstown,  N.  Y.  233 

WDM  Church  of  the  Covenant Washington.   D.  C.  234 

WDWF  Cranston.     R.    I.  440 

WDZ  J.  L.  Bush Tuscola.  IU.  278 

WEAA  F.  D.  Fillain Flint.  Mich.  250 

WEAF  Amerioan  Telephone  &  Telegraph  Co New  York,  N.  Y.  485 

WEAH  Wichita  Board  of  Trade Wichita.  Kans.  280 

WEAI  Cornell  University Ithaca.  N.  Y.  286 

WEAJ  University  of  South  Dakota Vermilion,  S.  Dak.  283 

WEAM  Borough  of  North  Plaiofield  (W.  Gibson  Buttfiold) . .  .North  Plainfield.  N.  J  286 

WEAN  Shepard    Co Providence,  R.    I.  273 

WEAO  Ohio  State  University Columbus,  Ohio  293 

WEAP  Mobile  Radio  Co Mobile.  Ala.  263 

WEAR  Goodvear    Tire   and    Rubber   Co Cleveland.    Ohio  389 

WEAU  Davidson  Bros.  Co Sioux  City.  Iowa  275 

WEAY  Iris  Theatre   (Will  Horowitz.  Jr.) Houston.  Texas  360 

WEB  Benwood    Co St.   Louis,    Mo.  273 

WEBA  Electric  Shop Highland  Park.  N.  J.  233 

WEBC  Walter    Cecil    Bridges Superior.    Wis.  242 

WEBD  Electrical  Equipment  and  Service  Co Anderson.  Ind.  246 

WEBE  Roy  W.    Walker Cambridge.  Ohio  248 

WEBH  Edeewater  Beach  Broadcasting  Station Chicago.  111.  370 

WEBI  Walter  H.  Gibbons Salisbury.   Md.  242 

WEBJ  Third  Avenue  Railway  Co New  York.  N.  Y.  273 

WEBM  Radio    Corporation    of    America Portable  226 

WEBP  E.   B.   Pedicord New   Orleans.    La.  280 

WEBT  The  Dayton  Coop.  Industrial  High  School Dayton.  Ohio  270 

WEBW  Beloit  College Beloit.  Wise.  283 

WEBX  John  E.  Cain.  Jr. Nashville,  Tenn.  263 

WEBY  Hobart      Radio      Co RosUndale.      Mass.  226 

WEEI  The  EdUon  Electrio  Illuminating  Co Boston.  Mass.  475 

WEMC  Barrier,  Springs.  Mich 205 

WEV  Hulbert-Still    Elec.    Co Houston.    Tex.  263 

WEW  St.    Louis    University : St.    Louis,    Mo.  280 

WFAA  Dallas  News  &  Dallas  Journal Dallas.  Texas  472 

WFAM  Times  Publishing  Co St.  Cloud.  Minn.  273 

WFAN  Hutchinson  Electric  Service  Co Hutchinson.  Minn.  286 

WFAV  University  of  Nebraska,  Department  of  Electrical  Engineering.  .Lincoln,  Nebr.  275 

WFBB  Eureka  College Eureka.  111.  240 

WFBC  First  Baptist  Church Knorville.  Tenn.  250 

WFBD  Gethsemane    Baptist    Church Philadelphia.    Pa.  234 

WFBE  John  Van  De  Walle Saeymour.  Ind.  226 

WFBG  The  Wm.  F.  Cable  Co Altoona.  Pa.  261 

WFBH  Concourse  Radio  Corporation New. York,  N.  Y.  273 

WFBJ  St.  John's  University CoUegeville.  Minn.  236 

WFBQ  Wynne  Radio  Co Raleigh.  N.  C.  255 

WFBR  Fifth  Inf.  Md.  Nat'l  Guard.  5th  Reg.  Armory Baltimore.  Md.  452 

WFBT  Gloucester  Co.  Civic  League Pitman.  N.  J.  231 

WFBW  Ainswortb-Gates      Radio      Co Cincinnati.  Ohio  309 

WFBY  Signal  Officer Ft.  Ben  Harrison.  Ind.  258 

WFBZ  Knox  College Galesburg.  111.  254 

WFI  Strawbridge  and  Clothier Philadelphia.   Pa.  394 

WFUV  G.  Pearson  Ward Springfield.   Mo.  252 

WFUW  Earl  William  Lewis Moberly.  Mo.  233 

WGAL  Lancaster  Electric  Supply  &  Construction  Co.. Lancaster,  Pa.  248 

WGAQ  Youree  Hotel :.v: Shreveport,  La.  252 

WGAZ  South  Bend  Tribune South  Bend.  Ind.  360 

WGBB  Harrv  H.  Carman.,  217  Bedell  St Freeport.  N.  Y.  244 

WGBC  First  Baptist  Church -.  i Memphis.  Tenn.  266 

WGBF  Finke  Furniture  Co Evansville,  Ind.  217 

WGBC  Brietenbaeh's     Radio     Shop Thrifton,     Va.  226 

WGBH  Fall    River    Herald    Puo.    Co (Portable)  209 

WGBI  Frank      S.       Megargee Scranton,       Pa.  240 

WGBK  Lawrence    Campbell Johnstown.    Pa.  248 

WGBL  Albert      H.      Ernest Elyria.      Ohio  227 

WGBS  Gimbel  Brothers New  York.  N.  Y.  315 

WGBT  Furman    University Greenville.    S.    C.  236 

WGI  American  R.  &  R.  Co Medford  Hillside.  Mass.  360 

WGL  Thos.   F.   J.   Howlett Philadelphia.   Pa.  360 

WGN  The    Tribune    Co Chicago,    111.  370 

WGR  Federal  T.  and  T.  Co Buffalo.  N.  Y.  319 

WGY  General  Elec.  Co Schenectady.   N.  Y.  385 

WHA  University    of    Wisconsin Madison.    Wis.  535 

WHAD  Marquette  University Milwaukee,  Wis.  280 

WHAG  University  of  Cincinnati Cincinnati    Ohio  222 

WHAH  Hafer   Supply    Co Joplin,    Mo.  283 

WHAM  University  of  Rochester  (Eastman  School  of  Music) Rochester.  N.  Y.  283 

WHAR  SeasideHouse Atlantic  City,  N.  J.  275 

WHAS  Courier-Journal  &  Louisville  Times ; Louisville,  Ky.  399 

WHAV  Wilmington  Electrical  Specialty  Co Wilmington,  Del.  360 

WHAZ  Rensselaer  Polytechnic  Institute Troy.  N.  Y.  385 

WHB  Sweeney  School  Co l\>nsas  City.  Mo.  365 

WHK  Radiovox     Company Cleveland.     Ohio  283 

WHN  George    Schubel New    York.    N.    Y.  360 

WHO  Bankers    Life    Co ". Des    Moines.    la.  522 

WIAC  Galveston  Tribune Galveston.  Texas  360 

WIAD  Howard  R.  Miller Philadelphia.  Pa.  254 

WIAK  Journal-Stockman  Co Omaha.  Nebr.  278 

WIAQ  Chronicle  Publishing  Co Marion.  Ind.  226 

WIAS  Home  Electric  Co Burlington.  Iowa  283 

WIK  K.    &   L.    Co McKeesport,     Pa,  234 

WIL  Continental    Electrio   Supply   Co Washington.    D.     C.  360 

WIP  Gimbel  Bros .. Philadelphia,  Pa.  509 

WJAB  American  Electric  Co Lincoln,  Neb.  229 

WJ  AD  Jackson's  Radio  Engineering  Laboratories Waco.  Texas  352 


WJAG       Norfolk  Daily  News Norfolk.  Nebr.     283 

WJAK      Clifford  L.  White ." Greentown,  la.     254 

WJAM      D-  M.  Perham Cedar  Rapids,  Iowa     268 

WJAN       Peoria    Star Peoria,    111.    280 

WJAR       The  Outlet  Co.  (J.  Samuels  4=  Bro.) Providence.  R.  I.     305 

WJAS        Pittsburgh  Radio  Supply  House Pittsburgh.  Pa.    283 

WJAX      Union  Trust  Co „  .  .Cleveland.  Ohio    390 

WJAZ       Chicago  Radio    Laboratory Chicago,  111.    268 

WJD  Denison  University Grantville.  Ohio     229 

WJJD        Supreme  Lodge,   Loyal  Order  of  Moose Mooseheart.     111.     302 

WJY  Radio  Corp.  of  Ama. New  York.  N.  Y.     454 

WJZ  Radio  Corp.  of  Ama New  York.  N.  Y.     455 

WKAA      H.  F.  Paar Cedar  Rapids, Iowa    278 

WKAD     Chas.  Looff  (Crescent  Park) East  Prov  idence  R.  I.    240 

WKAF      W.  S.  Radio  Supply  Co Wichita  Falls,  Texas    360 

WKAN     United  Battery  Service  Co Montgomery   Ala      226 

WRAP      Dutee  W.  Flint Cranston.  R.  I.    360 

WKAQ     Radio  Corp.  of  Porto  Rico San  Juan. P.  R.    360 

WKAR      Michigan  Agriculture  College East  Lansing,  Mich.    285 

WKAV      Laconia  Radio  Club Laconia,  N.  H.    254 

WKBF      Dutee  Wilcox  Flint Cransten.  Rhode  Island    286 

WKY|       Wky  Radio  shop Okla  City.    Okla.     275 

WLAG      Cutting  &  Washington  Radio  Corp Minneapolis,  Minn.     417 

WLAL       Naylor  Electrical  Co Tulsa.  Okla.    360 

WLAP       Wm.  V.  Jordan Louisville.  Ky.    286 

WLAQ      Artnur  E.  Shilling Kalamazoo.  Mich.    283 

WLAX       Putnam  Electric  Co Greencastle.  Ind.     231 

WLB  University  of  Minnesota Minneapols.  Minn.     278 

WLBL       Wisconsin  State  Dept.  of  Markets Stevenspoint,  Wis.     278 

WLS  Sears    Roebuck    &    Co Chicago.    IU.     344 

WLW         Crosley  Mfg.  Co Cincinnati,  Ohio     422 

WMAC     J.  Edw.  Page  (Olive  B.  Meredith) Cazenovia.N.  Y.    261 

WMAF     Round  Hills  Radio  Corp Dartmouth,  Mass.    360 

WMAH    General  Supply  Co Lincoln.  Nebr.    254 

WMAK     Norton  Laboratories Lockport.  N.Y.    273 

WMAL      Trenton  Hardware  Co Trenton  ,N.  J.     256 

WMAN     First  Baptist  Church Columbus,  Ohio    286 

WMAQ    Chicago  Daily  News Chicago,  111.    447 

WMAV     Alabama  Polytechnic    Institute Auburn,  Ala.    250 

WMAY     Kingshighway  Presbyterian  Church St.  Louis,  Mo.    280 

WMAZ     Mercer  University Macon,  Ga.    261 

WMBF      Miami    Beach,    Fla.     384 

WMC        Commercial     Appeal Memph  is.  Tenn .     503 

WMH        Ainsworth-Gates     Radio     Co Cincinnati,     O.     325 

WMU        Doublodal-Hill  Elec.  Co Washington.    D.  C.     261 

WNAC       Shepard  Stores Boston,   Mass.     280 

WNAD      University  of  Oklahoma Norman,  Okla.    254 

WN AL      Omaha  Central  High  School Omaha,  Nebr.     258 

WNAP      Wittenberg  College Springfield.  Ohio     275 

WNAR      First  Christian  Church Butler  .  Mo.     231 

WN  AT      Lennig  Brothers  Co.  (Frederick  Lennig) Philadelphia,  Pa.    250 

WNAX     Dakota  Radio  Apparatus  Co Yankton,   S.  Dak.    241 

WNYC      Dept.  of  Plant  and  Structures New  York.N.  Y.    528 

WOAC      Page  Organ  Co Lima.  Ohio    263 

WOAE       Midland  College Fremont,  Nebr.     280 

WOAF      Tyler  Commercial    College Tyler.  Texas    361 

WOAG      Apollo  Theater  (Belvidere  Amusement  Co.) Belvidere.  111.    271 

WOAI        Southern  Equipment  Co .- San  Antonio.  Texas    391 

WOAN  Vaughn  Conservatory  of  Musio  (James  D.  Vaughn) ....  Lawrenceburg,  Tenn.    282 

WOAO      Lyradion  Mfg.  Co ,  .  .Mishawaka.  Ind.    360 

WOAR      Lundskow.  Henry  P Kenosba.  Wis.    229 

WOAT      Boyd  M.  Hamp Wilmington ,  Del.    360 

WOAV      Pennsylvania  National  Guard,  2d  Battalion,  112th  Infantry Erie,  Pa.    242 

WOAW     Woodmen  of  the  World Omaha.  Nebr.    522 

WOAX      Franklyn  J.  Wolff Trenton,  N.  J.    240 

WOC  Palmer    School    of    Chiropractic Davenport,  la.     498 

WOCL       Hotel  Jamestown,  Inc Jamestown,  N.  Y.  275 

WOI  Iowa  State  College Ames  la.     270 

WOO  John  Wanamaker Philadelphia, Pa.     509 

WOR         L.  Bamberger  and  Co Newark. N.  J.     405 

WORD]    Peoples   Pulpit  Assn Batavia,   111.     278 

WOS  State    Marketing    Bureau Jefferson  City,  Mo.     440 

WPAB      Pennsylvania  State  College State  College.  Pa.     283 

WPAC       Donaldson  Radio  Co Okmulgee,  Okla.     360 

WPAJ       Doolittle  Radio  Corp New  Haven.  Conn.    268 

WPAK      North  Dakota  Agricultural  College Agricultural  College,  N.  D.    283 

WPAL       Superior  Radio  &  Telephone  Equipment  Co Columbus,  Ohio    286 

WPAU       Concordia  College Moorhead.    Minn.    286 

WPAZ       John  R.  Koch  (Dr.) Charleston.  W.  Va.    273 

WPG  The  Municipality  of  Atlantic  City Atlantic  City,  N.  J.    296 

WQAA      Horace  A.  Beale,  Jr Parkersburg.  Pa.     270 

WQAC      E.  B.  Gish amarillo,  Texas    234 

WQAE      Moore  Radio  News  Station  (Edmund  B.  Moore) Springfield.  Vt.    275 

WQAM     Electrical    Equipment    Co Miami.     Fla.     283 

WQAN      Scranton  Times Scranton,  Pa.     280 

WQAO      Calvary  Baptist  Church New  York.  N.  Y.     360 

WQAQ     Abilene  Daily  Reporter  (West  Texas  Radio  Co.) Abilene ,  Texas     360 

WQAS      Prince- Walter  Co Lowell.  Mass.    266 

WQJ     '     Calumet  Rainbo  Broadcasting  Co Chicago.  111.    447 

WRAA      The  Rice  Institute Houston,  Tex.     256 

WRAF      The  Radio  Club  (Inc.) Laporte  .Ind.     224 

WRAM     Lombard  College Galesburg.  111.    244 

WRAN      Black  Hawk  Electrical  Co Waterloo.  Iowa    236 

WRAO      St.  Louis  Radio  Service  Co St.  Louis.  Mo.     261 

WRAV      Antioch  College Yellow  Springs.  Ohio     242 

WRAW     Avenue  Radio  Shop  (Horace  D.  Good) Reading.  Pa.    238 

WRAX     Flaxon's  Garage Gloucester  City.  N.  J.    268 

WRBC      Imanuel  Lutheran  Church Valparaiso.  Ind.    2'8 

WRC  Radio  Corp.  of  Ama Washington.    D.  C.     468 

WREO      Reo  Motor  Car  Co Lansing,  Mich.     286 

WRHF      Washington    Radio   Hospital  Fund Washington.    D.   C.     256 

WRK         Doron  Bros Hamilton .  Ohio     360 

WRL  Union  College Schenectady.    N.Y.     270 

WRM        University  of  Illinois Urbana,  111.     273 

WRR         Police  and  Fire  Signal  Department Dallas,    Tex.     261 

WRW        Tarrytown  Radio  Res.  Labs Tarrytown.    N.Y.     273 

WSAB       Southeast  Missouri  State  Teachers  College Cape  Girardeau.  Mo.     275 

WSAC       Clemson  Agricultural  College Clemaon  College.  S.  C.     336 

WSAD      J.  A,  Foster  Co Providence.  R.  I.     261 

WSAG       Loren  Vanderbeck   Davis St.  Petersburg.  Fla.     264 

WSAI        United  States  Playing  Cards  Co Cincinnati.  Ohio    325 

WSAJ       Grove  City  College Grove  City,  Pa.    258 

WSAN       AUentown    Call    Publishing    Co Allentown.    Pa.     229 

WSAP       Seventh  Day  Adventirt  Church New  York.  N.  Y.     263 

WSAR       Doughty  &  Welch  Electrical  Co Fall  River.  Mass.    254 

WSAU       Camp  Marienfeld Chesham.  N.  H.     229 

WSAV       C.  W.  Vick  Radio  Construction  Co Houston,  Tex.     360 

WSAY  Irving  Austin  (Port  Chester  Chamber  of  Commerce).  .Port  Chester.  N.  Y.    233 

WS  AZ       Chas.  Electric  Shop Pomeroy ,  Ohio    258 

WSB  Atlanta  Journal Atlanta,    Ga.     428 

WSL  J.  and  M.  Elec.  Co :  .Utica,  N.Y.     273 

WSOE        School    of   Engineering MUwaukee.      Wis.     246 

WSRF       Hardem  Sales  and  Service Broadlands.  I1L     233 

WSUT       State  University  of  Iowa Iowa  City,  Iowa    498 

WTAB      Fall  River  Daily  Herald  Publishing  Co Fall  River.  Mass.    248 

WTAC      Penn  Traffic  Co Johnstown.  Pa.    360 

WTAF      Louis  J.  Gallo New  Orleans  ,La.    242 

WTAL      Toledo  Radio  &  Electric  Co Toledo.  Ohio    252 

WTAM     Willard  Storage  Battery  Co Cleveland,  Ohio    389 

WTAP       Cambridge  Radio  £  Electrio  Co Cambridge.  I1L    242 

WTAQ      S.  H.  Van  Gordon  &  Son Osseo.  Wis.    220 

WTAR      Reliance  Eectric    Co Norfolk  ,  Va.    280 

WTAS       Charles  E.  Erbstein Elgin  .  IU.    303 

WTAT      Edison  Electric  Illuminating  Co Boston,  Mass.  (portable)    244 

WTAU      Ruegg  Battery  .fc.  Electric  Co Tecumseh.  Nebr.    242 

WTAW     Agricultural  &  Mechanical  College  of  Texas College  Station.  Tex   280 

WTAX      Williams   Hardware    Co Streator.    111.  231 

WTAY      Oak  Leaves  Broadcasting  Station Oak   Park.  111.  283 

WTAZ      ThomasJ.    McGuire Lambertville.  N.   J.   283 

WTG         Kansas  State  AgriculturalCoUege Manhattan,  Kans.     273 

WTIC        Travelers  Insurance  Co Hartford,  Conn.     323 

WTX         H.  G.  Seal  Co Chicago.  IU.     268 

WWAD     Wrighti  Wright  (Inc.) Philadelphia.  Pa.    360 

WWAE     The  Alamo  BaU   Room JoUet.  I1L     242 

WWI         Ford  Motor  Co Dearborn  .  Mich.    273 

WWJ         Detroit  New3  (Evening  News  Assn.) Detroit.  Mich.    352 

WWL        Loyola  University New  Orleans  .La.    260 

WWOA     Michigan  College  of  Mines Houghton  .  Mich  .  244 


RADIO  AGE  for  March,  1925 

Getting  Through  the  "Locals" 

( Continued  from  page  65) 


The  Magazine  of  the  Hour         77 


without  posts,  and  if  the- strip  is  already 
labelled,  connections  may  be  more  easily 
made.  Bus  bar  is  suitable  for  wiring, 
although  a  much  easier  and  just  as 
effective  job  may  be  done  with  "fixture" 
wire,  obtainable  at  electrical  supply 
houses.  This  is  about  No.  16  in  size, 
well  covered  with  rubber  and  cloth  in- 
sulation. Leads  with  this  wire  may  be 
run  direct,  without  unnecessary  length 
due  to  right  angle  bends  and  the  like. 
Connections 

ALTHOUGH  the  audio  portion  of  the 
receiver  is  wired  in  the  customary 
manner,  the  leads  to  the  penetrator 
switch  may  be  somewhat  confusing. 
The  antenna  is  joined  to  one  of  the  long 
springs  of  the  switch  and  the  return 
from  the  radio  frequency  tickler  coil 
connected  to  the  other  long  spring.  There 
are  two  shorter  springs  for  each  of  the 
two  long  springs,  either  of  which  may 
be  brought  into  contact  with  the  long 
spring  according  to  the  position  of  the 
control  knob  or  handle.  In  one  case, 
the  entire  primary  coil  of  six  turns  is 
in  use,  while  in  the  other,  only  two  turns 
are  employed.  It  is  important  to  get 
the  2-2  combination  and  the  6-6  com- 
bination working  in  unison,  for  it  is  easy 


enough  to  reverse  them  and  have  two 
turns  in  one  primary  when  the  other  is 
connected  for  six.  It  will  be  noticed  that 
the  tickler  coil  is  not  in  the  plate  circuit 
of  the  first  R.  F.  tube,  even  though  it 
is  the  first  R.  F.  tube  that  is  tuned  by 
the  R.  F.  condenser  and  coupler.  The 
tickler  feed-back  is  made  from  the  plate 
of  the  second  R.  F.  tube,  whose  grid  is 
fed  by  the  iron-core  transformer.  Thus 
advantage  is  taken  of  the  amplifying 
effect  of  both  tubes  upon  the  regeneration 
available. 

With  regard  to  the  R.  F.  transformer 
chosen,  the  type  mentioned  is  used  on 
account  of  its  high  natural  wavelength 
"peak."  Most  R.  F.  transformers  have 
a  lower  "peak"  wavelength  and  as  such 
are  not  as  satisfactory  because  of  the 
greater  readiness  with  which  the  two 
R.  F.  tubes  get  into  oscillation  upon 
each  other.  However,  other  R.  F.  trans- 
formers will  answer  if  their  secondary 
windings  are  shunted  by  a  small  variable 
condenser  (inside  the  set)  of  about 
.00025  mfds.  and  adjustment  made  for 
the  best  fixed  point,  or  if  a  potentiometer 
is  bridged  across  the  A  battery  wires  and 
the  grid  return  from  the  transformer 
(F — )  made  to  its  movable  arm. 


Have  you  ever  heard  of  the  "Hoot  Owls"?  They  compose  one  of  the 
most  interesting  radio  clubs  in  the  world.  An  unusual  account  of  their 
origin  and  present  activities  will  be  a  feature  of  the  all-star  April  RADIO 
AGE. 


Straight  Line  Low  Loss 
Condensers 

Increased  distance  and  volume,  better  still, 
much  greater  Selectivity  are  certain  results 
with  DXL  Straight  Line  Low  Loss  Variable 
Condensers.  No  DXL  Condenser  leaves 
the  factory  that  doesn't  meet  the  quality 
tests  outlined  by  DXL  engineers.  Set 
builders  can  use  DXL  Condensers  right  out 
of  the  carton  with  the  certainty  that  each 
one  is  perfect.  Use  DXL  Condensers  and 
you  are  sure  of  the  best  performance. 

New  DXL  Kit 

Now  ready— the  DXL  5  Tube  Tuned  R.  F. 
Receiver  Kit  absolutely  Straight  Line  and 
Low  Loss.  Will  separate  two  stations  only 
6  meters  apart,  broadcasting  simultaneously. 
No  squeals,  non-oscillating,  coast  to  coast 
reception  on  loud  speaker.  Less  static  inter- 
ference. Positive  results  guaranteed  if  built 
in  accordance  with  detailed  instructions  and 
blue  print,  free  with  every  DXL  Kit. 

Get  a 


DXL  RADIO  CORPORATION 
5765  Stanton  Ave.  Detroit,  Michigan 


Radio  Age  Institute 

Manufacturers'  Testing  Service 

"\TEMBERS  of  the  staff  of  RADIO  AGE  will  be  pleased  to  test  devices 
J-'A  and  materials  for  radio  manufacturers  with  the  object  of  deter- 
mining their  efficiency  and  worth.  All  apparatus  which  meets  with 
the  approval  of  various  tests  imposed  by  members  of  the  technical 
staff  of  RADIO  AGE  will  be  awarded  our  endorsement,  and  the  seal 
shown  to  the  left  will  be  furnished  free  of  charge.  Materials  for 
testingshould  be  sent  to 

RADIO  AGE  INSTITUTE 

504  N.  Dearborn  Street,  Chicago,  111. 


DEVICES 

displaying  this  seal 
have  been  tested 
and  approved  by 
the  RADIO  AGE 
INSTITUTE. 

Theapparatusillus- 
t  r  a  t  e  d  and  des- 
cribed below  have 
successfully  passed 
our  tests  for  March 
1925. 


Test  No.  34.  THE  PACENT  IM- 
PROVED AUDIOFORMER.  The 
pacent  audio  frequency  transformer, 
especially  designed  for  broadcasting 
frequencies.  It  is  exceptionally  well 
designed  and  has  a  very  good  curve 
which  covers  the  range  of  audio 
frequencies  commonly  in  use  at 
broadcasting  stations.  The  trans- 
former is  quite  large  in  size  and  is 
very  efficiently  shielded,  giving  maxi- 
mum amplification  with  a  minimum 
of  distortion.  Manufactured  by  the 
Pacent  Electric  Co.,  23  Park  Place, 
New  York  City,  N.  Y.  Tested  and 
approved  by  RADIO  AGE  Institute. 


Test  No.  35.  THE  ELECTRAD 
"AUDIOHM."  A  device  manu- 
factured by  the  Electrad  Co..  428 
Broadway,  New.  York  City,  N.  Y. 
Controls  tone,  quality  and  volume; 
can^also  be  used  for  resistance  coupled 
amplifiers.  It  has  a  resistance  rang- 
ing from  10,000  to  120,000  ohms,  and 
works  very  well  when  placed  across 
the  secondary  of  the  last  audio  fre- 
quency transformer.  Distortion  was 
practically  eliminated  by  the  use  of 
this  instrument.  The  device  is  very 
well  made  and  arrived  in  excellent 
condition.  Tested  and  approved  by 
RADIO  AGE  Institute. 


Test  No.  36.  "CELERON"  sub- 
mitted by  the  Diamond  State  Fiber 
Co. ,  Philadelphia,  Pa.  Several 
samples  of  the  above  material  were 
received  last  month.  Their  composi- 
tion known  as  "Vulcawood"  was  ^rst 
tested  and  found  to  be  very  satisfac- 
tory. "Vulcawood"  is  primarily  in- 
tended to  be  used  as  a  material  for 
cabinet  construction.  It  is  furnished 
by  the  above  company  either  in  the 
regular  manner  (cut  to  size)  or  in 
packages  containing  complete  parts 
for  a  standard  size  cabinet,  metal  end 
plates,  etc.  It  was  found  to  be  very 
satisfactory,  has  high  insulation 
qualities  and  is  not  affected  by  heat 
or  dampness.  The  lustre  was  found 
to  be  of  a  lasting  quality  and  it  is 
practically  impossible  to  warp  "Vul- 
cawood," which  passed  successfully 
the  tests  and  requirements  of  RADIO 
AGE  Institute. 


Test  No.  37.  The  A.  H.  Miller 
Radio  Co.,  1259  W.  Grand  Blvd.. 
Detroit,  Michigan,  submitted  one  of 
their  "Battery  Crystals."  After  a 
very  thorough  test,  we  do  not  hesitate 
in  placing  our  approval  on  this  crystal 
detector.  It  has  proven  itself  to  be 
a  very  valuable  asset  in  reflex  circuits, 
and  worked  much  better  than  the 
ordinary  crystal  in  all  circuits  in 
which  it  was  tried.  No  tests  were 
made  to  determine  its  life.  But  from 
indications  it  should  last  much  longer 
than  the  ordinary.  Tested  and  ap- 
proved by  RADIO  AGE  Institute. 


¥     Tested  and  Approved  by  RADIO  AGE     # 


78 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


Canadian  Stations 


CFAC 

CFCA 

CFCF 

CFCH 

CFCJ 

CFCK 

CFCN 

CFCQ 

CFCR 

CFCT 

CFCU 

CFCW 

CFDC 

CFHC 

CFLC 

CFQC 

CFRC 

CFUC 

CFXC 

CFYC 

CHAC 

CHBC 

CBCB 

CHCD 

CHCE 

CHCL 

CHCM 

CHCS 

CHNC 


PWX 

2DW 

2AB 

20K 

2BY 

2CX 

2EV 

2TW 

2HC 

2LC 

2KD 

2MN 

2MG 

2JD 


Calgary  Herald Calgary,  Alberta  430 

Star  Pub.  &  Prtg.  Co Toronto,  Ontario  400 

Marconi  "Wireless  Teleg.  Co.  of  Canada Montreal,  Quebec  440 

Abitibi  Power  &  Paper  Co Iroquois  Falls,  Ont.  400 

La  Cie  de  L'Evenement Quebec.  Quebec  410 

Radio  Supply  Co Edmonton,  Alberta  410 

W.  W.  Grant  Radio  (Ltd.) Calgary .  Alberta  440 

Radio  Specialties  (Ltd.) Vancouver.  B.  C.  450 

Laurentide  Air  Service Sudbury.  Ont.  410 

Victoria     City     Temple Victoria.     British     Col.  410 

The  Jack  Elliott  Radio   Limited Hamilton,    Ont.  410 

The  Radio  Shop London,  Ont.  420 

Sparks  Co Nanaimo,  B.C.  430 

Henry  Birks  &  Sons Calgary.   Alta.  440 

Chas.  Guy  Hunter 551  Adelaide  Sc,  London,  Ont.  410 

The  Electric  Shop  (Ltd.) Saskatoon,  Saskatchewan  400 

Queens  University Kingston,  Ontario  450 

University  of   Montreal Montreal,   Quebec  400 

"Westminster  Trust  Co New  "Westminster  B.  C.  440 

Victor     "Wentworth     Odium Vancouver.     B.     C.  400 

Radio  Engineers Halifax.  Nova  Scotia  400 

Albertan  Publishing  Co Calgary,  Alberta  410 

Marconi  Company Toronto,  Ont.  410 

Canadian  Wireless  &  Elec.  Co Quebec.  Quebec  410 

Western  Canada  Radio  Sup.  (Ltd.) Victoria,  B.  C.  400 

Vancouver  Merchants  Exchange Vancouver.  B.  C.  440 

Riley  &   McCormack Calgary.  Alberta  415 

The  Hamilton  Spectator Hamilton.  Ont.  420 

Toronto     Radio     Research Toronto,     Ont.  350 


CHXC  J.    R.    Booth Ottawa.    Ont. 

CHYC  Northern  Electric  Co Montreal,  Quebec 

CJBC  Jar-vis    Baptist    Church Toronto.    Ont. 

CJCA  Edmonton  Journal Edmonton.  Alberta 

CJGC  London  Free  Press  Prtg.  Co London,  Ont. 

CJCD  T.  Eaton  Co Toronto,  Ont. 

CJCE  Sprott-Shaw  Radio  Co Vancouver,  B.  C. 

CJCF  The  News  Record Kitchener.  Ont. 

CJCI  Maritime  Radio  Corp St.  John,  New  Brunswick 

CJCK  Radio  Corp.  of  Calgary Calgary,  Alta. 

CJCM  J.  L.  Phillipe Monti  Joli,  Quebec 

CJCN  Simons  Agnew  c%  Co Toronto.  Ont. 

CJSC  Evening  Telegram Toronto.  Ont. 

CKAC  La  Presse  Pub.  Co Montreal.  Quebec 

CKCD  Vancouver  Daily  Province Vancouver.  B.  C. 

CKCE  Canadian  Independ.  Telephone  Co Toronto.  Ont. 

CKCK  Leader  Pub.  Co Regina.  Saskatchewan 

CKCO  Ottawa  Radio  Association Ottawa,  Ont. 

CKCX  P.  Burns  &  Co Calgary.  Alberta 

CKLC  Wilkinson  Electric  Company Calgary.  Alberta 

CKOC  Wentworth  Radio  Supply  Co Hamilton,  Ont. 

CKY  Manitoba  Telephone  System Winnipeg,  Manitoba 

CNRC  Canadian  National  Railways Calgary,  Canada 

CNRE  Canadian       National       Railways Edmonton,       Alta. 

CNRM  Canadian    National    Railways Montreal,    P.    Q. 

'    CNRO  Canadian  National  Railways ". Ottawa.  Ont. 

CNRR  Canadian    National    Railways Regina,    Sash. 

CNRS  Canadian     National     Railways Saskatoon,     Sash. 

CNRT  Canadian     National     Railways Toronto,     Ont. 

CNRW  Canadian    National    P*ailways Winnipeg,    Man. 


Cuban  Stations 


Cuban  Telephone  Co Habana 

Pedro  Zayas Habana 

Alberto  S.  de  Bustamante Habana 

Mario  Garcia  Velez Habana 

Frederick  W.  Borton Habana 

Frederick  W.  Borton Habana 

Westinff  house  Elec.  Co Habana 

Roberto  E.  Ra mires Habana 

Heraldo  de  Cuba Habana 

Luis  Casus : Habana 

E.  Sanchez  de  Fuentes Habana 

Fausto  Simon Habana 

Manuel  G.  Salas Habana 

Raul  Perez  Falcon Habana 


400 

2K 

300 

2HS 

240 

20L 

360 

2WW 

260 

5EV 

320 

6KW 

220 

6KJ 

230 

6CX 

275 

6DW 

250 

6BY 

350 

6AZ 

270 

8BY 

280 

8FU 

150 

8DW 

435 
410 
312 
455 
430 
410 
420 
295 
400 
316 
430 
410 
430 
430 
410 
450 
420 
440 
440 
400 
410 
450 
440 
455 
340 
430 
400 
412 
400 
450 


Alvara  Daza Habana  200 

Julio  Power Habana  180 

Oscar  Collado Habana  290 

Amadeo  Saenz Habana  210 

Leopoldo  V.  Figueroa Colon  360 

Frank  H.  Jones Tuinucu  340 

Frank  H.  Jones Tuinucu  27S 

Antonio  T.  Figueroa Cienfiegos  170 

Eduardo  Terry Cienfiegos  225 

Jose   Ganduie Cienfiegos  300 

Valentin  Ullivarri Cienfiegos  200 

Alberto  Ravelo Stgo.  de  Cuba  250 

Andres  Vinnet • Stgo.  de  Cuba  225 

Pedro  C.  Anduz ." Stgo.  de  Cuba  275 


THE  RADIO  AGE  BUYERS'  SERVICE 


What  do  you  want  to  purchase  in  the  radio  line? 
Enter  the  number  of  the  article  you  would  like  to  know 

57  Couplers,  Ii 


Let  the  staff  of  RADIO   AGE  save  you 
more  about  in  the  spaces  provided  in  the 


1  "A"  Batteries 

2  Aerial  protectors 

3  Aerial  insulators 

4  Aerials 

5  Aerials,  loop 

6  Amplifiers 

7  Amplifying  units 

8  Ammeters 

9  "B"  batteries 

10  Batteries   (state  voltage) 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery  substitutes 

17  Bezels 

18  Binding  posts 

19  Binding  posts,  insulated 

20  Books 

21  Boxe?,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatston- 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisera 

33  Coils 

34  Coils,  choke 

35  Coils,  coupling 

36  Coils,  filter 

37  Coils,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance 

40  Coils,  Reinartz 

41  Coils,  stabilizer 

42  Coils,  tuning 

43  Condenser  parts 

44  Condenser  plates 


46  Conde 

47  Conde 

48  Conde 

49  Conde 


58  Couplers,  molded 

59  Couplers,  vario 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 
"    al,  adju 


72   Dials 


npositi. 


73 

Dials. 

hard  rubber 

74 

Dials, 

rheostat 

75 

Dials, 

metal 

76 

Dials, 

77 

Dials 

with  knobs 

78 

Dies 

79 

Drills 

electric 

80  Dry  cells 

81 

Earth 

ground. 

82 

Electr 

olyte 

S3 

Enam 

els,  battery 

K4 

Enamels,  metal 

85 

Ends 

lops 

Sfi 

Eyelets 

87 

Experimental  work 

88 

Fibre 

sheet,  vulcan 

as 

Filter 

reactors 

92  Fus 

93  Cen 


,  tube 

ators,  high  frequ 


94  Grid  choppers, 

95  Grid  leak  holde 

96  Grid,  transmitting  leaks 

97  Grid  leaks,  tube 

98  Grid  leaks,  variable 

99  Grinders,  electric 

100  Ground  clamps 

101  Ground  rods 

102  Handles,  switch 

103  Head  bands 
ad  pho 


pho 


50  Con 

51  Condensers,  variable 

52  Condensers,  vernier 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  sets 


104  He 

105  He 

106  He 

107  He 

108  Hot 

109  Hot 

110  Ho> 

111  Hoi 

112  Hoi 


ets 


eycomb  coil  adapte 


114  In 

115  Indu.tan. 

116  Insulatioi 

117  Insulatioi 

118  Insulator: 

119  Insulator. 

120  Insulator: 

121  Insulator: 

122  Insulator, 
ulator: 


composition 

high  voltage 

cloth 

glass 

hard  rubber 


123  In 

124  In 

125  Insulator: 

126  Irons,  soldering 

127  Jacks 

128  Filament  control 

129  Jars,  battery 

130  Keys,  transmitting 

131  Knobs 

132  Knock-down  panel  units 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arresters 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  units 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instruments 

142  Megohmcters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeters 

148  Minerals 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,       condenser 
leak 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,  honeycomb 

156  Mountings,     inductance 
switch 

157  Name  plates 

158  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeters 

161  Oscillators 

162  Panel  ci 

163  Panels, 
drilled 

164  Panels, 

165  Panels, 

166  Parts 

167  Paste,  s 


tting  and  drilling 
drilled     and     un- 


170 
171 
172 
173 

174 
175 
176 
177 
17s 
179 
ISO 


time  and  money  by  sending  in  the  coupon  below, 
coupon. 

Patent  attorneys  221  Solder  salts 

Phone  connectors,  multi-  222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 
ill                                               226  Stampings 

227  Stators 

228  Stop  points 

229  Switch  arms 

230  Switch  levers 
'itch  points 

itch  stops 


ndkn 


Plugs,  telephoi 
Pointers,  dial  e 
Poles,  aerial 
Potentiometers 
Punching  machines 
Reinartz  set  parts 
Regenerative  set  parts 


al 


181    Rectifiers,  battery 


182 

Resis 

tance 

leaks 

183 

Resis 

units 

184 

Rheo 

stat  bases 

1 85 

Rheo 

stat  s 

trips 

186 

Rheo 

stats, 

auton 

natic 

187 

Rheo 

stats. 

battery 

IKK 

Rheo 

dial 

189 

Rheostats, 

filam 

;nt 

1  SKI 

Rheo 

pote 

ntiometer 

141 

Rheo 

stats. 

192 

Rheo 

stats, 

193 

Rods 

nd 

194 

Roto 

I9S 

Scrapers,  v. 

196 

147 

I9fl 

dio 

199 

Sets, 

recei 

cabinet 

■.'HO 

Sets, 

:rystal 

■Jul 

Sets, 

down 

202 

Sets, 

receiving 

—    Neu- 

203 

Sets, 

portable 

204 

Sets, 
quen 

cy 

ving— 

radio   fre- 

20S 

Sets. 

receiving- 

-reflex 

206 

Sets, 

rece 

iving— 

-regenera- 

207 

Sets, 

rece 

Reinartz 

2<)S 

Sets, 

recei 

ving — sectional 

21)4 

Sets, 

recei 

short  wave 

210 

Sets. 

rece 

iving- 

-super-re- 

nductan 
>anel 
ingle  an 


231 

232  S 

233  S 

234  Switches,  battery 

235  Switches    "' 

236  Switches 

237  Switches 

238  Switches 

239  Switches 
ble  I hrov 

240  Tone  wh 

241  Towers,  : 

242  Transfor 


243  Transformers, 

244  Transformers, 

245  Transformers, 

246  Transformers, 

247  Transformers, 


push-oull 
radio     Ire- 


211 
212 
213 
214 
215 
216 
217 
218 
219 
220 


248  Transformers, 

249  Transmitters 

250  Tubes,  vaccuu 

251  Tubes,    vacuui 

252  Tubes,  vacuun 

253  Tuners 

254  Variocouplers, 

255  Variocouplers, 

256  Variocouplers, 

257  Variometers,  r 

258  Variometers,  molded 

259  Variometers,  wood: 

260  Varnish,  insulating 

261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 

265  Wire,  aerial 


ded 
den 
bber 


Sliders 
Socket  adapte 

Solder 

Soldering  iron 
Soldering  past 
Solder  flux 


266  Wb 
ed 

267  Wir 

268  Wir 

269  Wir 

270  Wir 

271  Wir 

272  Wir 


tided  and  strand- 


,  Liti 
:,  magnet 
:,  platinum 
:,  tungsten] 


J      RADIO   AGE   BUYERS'  SERVICE,  500  N.  Dearborn  St.,  Chicago,  111. 

f                Please  see  that  I   am    supplied  with  buying  specification;    and    prices  on   the   articles  numbered  herewith: 

!                   1       1       1       1       1       1       1 

1        1        1        1        1        1        1 

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(                                                lama —  Q  Dealer                   ^]   Jobber 

J    Mfgrs.'   Rep.               Q    Manufacturer 

State   ._ 

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McLaughlin's 
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Make  BIG  MONEY! 
>— IN  RADIO — 

We  Need  Men-Can  You  Qualify? 

Ozarka  representatives  make  real  money  be- 
cause they  give  real  values  and  deliver  a  real 
service.  For  instance,  there  is  a  4-tube  Ozarka 
Instrument  for  loud  speaker  operation,  giving 
wide  range  of  reception  at  $39.50.  Our  men 
demonstrate  Ozarka  Instruments  and  Install. 
The  Instrument  makes  the  sale  easy  by  its  perfor- 
mance. We  train  yon  to  know  radio  and  oar  methods, 
make  yon  worthy  to  wear  the  Ozarka  button  as  oar 
accredited  representative.  Previous  experience  is  not 
necessary.  In  fact  we  prefer  to  do  our  own  educating. 
If  you  have  a  clean  record,  are  industrious,  and  have 
saved  up  a  tittle  cash,  here's  a  real  opportunity,  if 
you  can  qualify  for  an  exclusive  territory .  We  already 
have  2247  representatives.    Territory  going  fast. 

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WRITE  Today  for  illustrated 
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860  Washington  Blvd. 
CHICAGO 

4  tube  Sets  AsaL°w  $3950 


Ready   For  The  WLS— 
RADIO  AGE  Party? 

"  A  LL-ABOARD— for  the  WLS  air- 
|  -^*-  plane  ride  into  Harmony  Land — 
with  Ford  and  Glenn  and  the  RADIO 
AGE  broadcast  artists!" 

The  foregoing  is  probably  what  George 
Hay,  announcer  of  WLS  and  one  of  the 
most  popular  radio  announcers  in  the 
country,  will  say  when  he  opens  WLS' 
RADIO  AGE  program  at  7  o'clock, 
Friday,   March  6. 

Ford  and  Glenn  (known  in  public  as 
Ford  Rush  and  Glenn  Rowell),  the  original 
"How  Do  You  Do  Boys,"  will  start  the 
harmony  moving  with  their  inimitable 
"Lullaby  Time"  melodies.  About  7:15 
the  RADIO  AGE  artists  will  take  charge, 
and,  lulled  by  "The  Solemn  Old  Judge's" 
crooning  voice,  a  galaxy  of  popular  and 
old-time  favorites  will  be  presented,  the 
program  lasting  until  8  o'clock  on  the  dot. 

Among  the  stars  expected  to  appear 
for  RADIO  AGE  will  be  The  Belwyn 
Four-RADIO  AGE  Quartet;  Grace  Wil- 
son, contralto,  who  is  well  known  to 
WLS  fans;  Arthur  W.  Hickman,  ex- 
clusive RADIO  AGE  artist  whose  rich 
baritone  voice  has  been  declared  perfect 
for  radio  broadcasting;  and  the  RADIO 
AGE  Music  Masters,  a  group  of  talented 
musicians  who  will  acknowledge  requests 
for  well-known  selections. 

This  will  be  the  second  time  RADIO 
AGE  has  broadcast  from  WLS,  the  Sears- 
Roebuck  Station  on  the  Hotel  Sherman, 
Chicago,  and  many  fans  will  be  pleased 
to  hear  that  our  artists  will  be  heard 
again  from  this  popular  station. 

So  tune  in  on  345  meters,  folks,  on 
Friday  night,  March  6,  from  7  to  8 
o'clock,  and  let  that  expert  aviator,  Ford 
Rush,  guide  you  into  clouds  of  musical 
ecstacy! 

Pfanstiehl  Offices  In   Chicago 

The  Pfanstiehl  Radio  Co.  announces 
the  opening  of  offices  at  11  South  La- 
Salle  St.,  Chicago.  The  office  will  be  in 
direct  charge  of  Edmund  H.  Eitel,  Vice 
President,  who  has  been  with  the  Pfan- 
stiehl organization  from  its  beginning. 

Mr.  Alex  Poole,  formerly  with  the 
Kennedy  Co.  has  been  appointed  District 
Sales  Manager  with  an  office  at  this 
address.  Mr.  Poole  has  been  in  radio 
from  its  beginning  and  has  a  wide  ex- 
perience in  radio  merchandising.  Mr. 
Poole  will  make  his  headquarters  in 
Chicago,  and  his  organization  will  keep 
in  contact  with  Pfanstiehl  jobbers  and 
dealers  in   the   five  adjacent  states. 


The  Magazine  of  the  Hour        79 


ssigp 


Write  for 
$1.10  FREE 

EVERYWHERE  Hookup^ 

No  rheostat  knobs  on  panels  to  turn — no  meters 
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matically supplies  just  the  right  current  for  each 
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thermo-electric  principle.  Simplifies  wiring.  Re- 
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Did  You  Solve  the  Cross- 
Word  Puzzle? 

At  the  left  is  the  correct  solution  of  the 
cross-word  puzzle  published  in  last 
month's  RADIO  AGE  for  the  cross-word 
fans.  Most  of  the  terms  concerned  radio, 
and  quite  a  few  of  the  fans  sent  in  the 
correct  solutions,  although  a  few  were 
baffled  by  the  abbreviations. 

The  names  of  the  first  winners  will  be 
published  in  April  RADIO  AGE,  along 
with  another  puzzle  for  the  "advanced" 
radio  cross-word  students.  If  you 
haven't  yet  tackled  these  radio  brain- 
ticklers,  get  your  February  RADIO  AGE 
and  try  your  luck.  Send  your  completed 
puzzle  to  the  Puzzle  Editor  care  Radio 
Age. 


¥     Tested  and  Approved  by  RADIO  AGE     ¥ 


80 


RADIO  AGE  for  March,  1925 


The  Magazine  of  the  Hour 


The  Best  Radio  Hookups 


are  in 


RADIO  AGE  ANNUAL 

for  1925 

A  Thirty-Two  Page  Blueprint  Section 
is  Only  One  of  its  Many  Features! 


AMERICA'S  radio  fans  have  been  quick  to  respond 
■t*-  to  the  announcement  that  the  RADIO  AGE 
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already  been  sold,  and  universal  appreciation  is  being 
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ANNUAL  for  1925. 

THE  ANNUAL  for  1925  is  the  result  of  three  years 
of  constant  research  work  and  experiments  by  the 
staff  members  and  writers  of  RADIO  AGE.  It  is 
the  cream  of  the  radio  hookups  that  have  made  their 
appearance  since  the  birth  of  radio  and  have  won 
lasting  favor  with  America's  millions  of  radio  en- 
thusiasts. 

One  hundred  and  twenty  pages  of  new  hookups, 
construction  articles,  and  kindred  subjects  in  the  radio 
field  compose  the  unusual  contents  of  the  RADIO 
AGE  ANNUAL  for  1925.  No  other  book  has  ever 
been  printed  approaching  its  excellence.  No  other 
book  can  be  found  that  will  give  you  such  a  variety 
of  hookups  and  "How  to  build"  articles. 


THE  predominating  feature  of  the  RADIO  AGE 
ANNUAL  for  1925  is  the  big,  thirty-two  page  blue- 
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efficient  neutrodynes,  reflexes  and  super-heterodynes. 
The  kind  of  blueprints  that  made  the  RADIO  AGE 
monthly  section  the  talk  of  the  radio  world.  Use  them 
as  actual  working  drawings.  Every  one  of  the  hookups 
in  the  blueprint  section  and  in  the  rest  of  the  Annual 
has  been  thoroughly  tested  by  experts  in  our  radio 
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THOUSANDS  of  Annuals  sold  last  year  on  a  money- 
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Our  first  press  run  is  but  25,000  copies.  First  names 
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Copy  FOR  1925 

Some  of  the  Features   You  11  Find 
In  This  Wonder  Hookup  Book 


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How  to  read  and  understand  hookups. 
How  to  understand  radio  phenomena. 
Building  your  first  simple  set. 
How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set. 
How  to  amplify  any  kind  of  set. 
Making  a  reflex  set. 
Building  your  first  Reinartz  set. 
The  renowned  Baby  Heterodyne  No.  1. 
Adding  audio  and  radio  stages  to  the  Baby  Het. 
How  to  make  a  battery  charger. 
How  to  make  a  loud  speaker. 

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How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super-heterodyne  for  the  super  experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

AND  MANY  OTHER  UP-TO-THE-MINUTE  HOOKUPS  AND 
ARTICLES. 


RADIO  AGE  ANNUAL  COUPON 

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500  North  Dearborn  St.,  Chicago,  III. 

Gentlemen:       I  want  to  be  one  of  the  first  to  get  the  RADIO  AGE  ANNUAL  FOR  1925.       Enclosed  find  $1.00.       If 
I  am  not  satisfied  with  the  ANNUAL  I  will  return  it  within  five  days  and  you  will  refund  my  dollar. 

Name - - - 

Address - . ~~ 

City - - .....State 

3-25 


Not  Merely  a  Clear  Receiver,  but 

a  Fine  Musical  Instrument 


D  0/4  tc\  ls  becoming  as  much  of  a  household  con- 
*VdVMVF  venience  as  the  telephone.  It  should  be 
just  as  dependable  and  true.  Quality  of  tone  is  the 
supreme  test.  Distance  can  always  be  obtained  by  suf- 
ficient amplification.  The  problem  is  to  secure  dis- 
tance without  distorting  or  blurring  the  tone. 

Fflf*  \7P51fQ  radio  engineers  have  realized  this. 
*■  *J*-  yCdla  While  the  public  was  going  wild 
over  reaching  out  for  distance,  they  were  quietly  ex- 
hausting every  resource  in  experimentation  to  over- 
come the  internal  noises  which  increased  with  every 
new  stage  of  amplification.  The  same  steps  which 
amplified  the  tone  also  amplified  the  stray  oscilla- 
tions within  the  set  itself,  as  a  by-product. 

Nobody  knew  ^Ct 

employed  to  choke  them  or  neutralize  them.  Poten- 
tiometers, extra  condensers,  complicated  wiring  were 
employed  with  only  partial  success.  They  work  only 
when  perfectly  adjusted,  and  their  operation  inter- 
feres with  a  perfectly  pure,  free,  flexible  tone.  By  ab- 
sorbing the  true  signal  as  well  as  the  stray  energy, 
they  lose  or  blur  those  delicate  overtones  which  make 
real  music.  They  cannot  prevent  the  conflict  which 
occurs  in  the  circuit  between  the  forward  stream  of 
radio  energy  and  the  feedback  of  stray  energy,  blot- 
ting out  the  overtones. 

The  real  trouble  7S$:V!Z££ 

long-distance  radio  system  had  been  designed.  All  de-  . 


Brings  out  the 

Overtones — 

the  Rich  Timbre 

of  both  Music  and 

the  Human  Voice 


signs  up  to  date  generated  feedback  of  stray  energy 
which  chattered,  howled  and  squealed  unless  choked 
down  or  neutralized;  and  radio  reception,  while 
accomplishing  wonders,  was  still  a  makeshift. 

A  New  Capability  in  Radio: 

Overtones 

Perfectly  Reproduced 

Pfanstiehl's  big  contribution  to  radio  lies  in  his  dis- 
covery of  the  real  causes  of  oscillations  and  his  com- 
plete elimination  of  them  by  a  circuit  system  which 
KEEPS  THEM  OUT.  No  choking  or  neutralizing  ele- 
ments are  any  longer  needed.  No  adjusting  is  required. 
The  receiver  is  always  at  its  best.  Tuning  and  opera- 
tion are  absolutely  quiet.  The  tone  or  voice  comes  in 
sweetly,  in  all  of  its  natural  richness.  All  of  the  over-  ' 
tones  are  perfectly  reproduced,  exactly  as  transmitted . 
This  is  true  of  long  distance.  High  amplification 
doesn't  distort.  His  invention  has  turned  radio  from 
a  stunt  device,  for  fans  to  play  with,  to  a  dependable, 
enjoyable  and  trouble-proof  instrument  in  the  home 
— the  thing  it  should  be  and  was  destined  to  become. 

See  the  new  Pfanstiehl  at  your  radio  or 
music  dealer's.  If  he  does  not  have  one 
to  show  you,  we  can  quickly  get  it  to  him. 

Dealers:  Write  for  the  Pfanstiehl  proposition. 

PFANSTIEHL  RADIO  COMPANY 

Highland  Park  2  2  Second  Street  Illinois 


OVERTONE  RECEIVER 

A  5-tube  Receiver  using  the  nerv  system  of  tuned  radio  frequency 


%•     Tested  and  Approved  by  RADIO  AGE     ¥ 


€R05kE¥AGAIN  LOWERS  PRICES 

Big  Reduction  in  Famous  Trirdyn  and  other  Radios 


$1412 


m 


A  one-tube  radio 
that  easily  brings 
in  distance  with 
phones 


$181?  ewiP 


GfrOSfcE* 

'51' Portable 


$23i£ 


$30 


A  three-tube  regen-p-Oil.Ci-FV 

eratire  set  that  geti &™£g[P  L 

distance  with  the 

loud  speaker. 

Becoming  more 

popular  every 

day. 


The  biggest  selling  high  grade  receiver  on  the  market 
—the  Crosley  Trirdyn — reduced  from  $65  to  $50. 

The  Trirdyn  Special — the  beautiful  Model  with  cabi- 
net to  house  batteries — formerly  $75,  now  $60. 

The  Crosley  51-P,  a  tremendous  seller  at  $25,  reduced 
to  $23.50. 

We  unhesitatingly  state  that  these  sets,  together 
with  the  other  Crosley  Radios,  represent  the  biggest 
values  ever  offered. 

CROSLEY  RADIOS  JUSTLY  POPULAR 

Only  the  less  expensive  Crosley  Radios  have  exceeded 
the  Trirdyn  in  sales.  This  deserved  popularity  of  the 
entire  Crosley  line  is  the  result  of  extraordinary  per- 
formance at  a  very  low  price. 

Crosley  Radios  cost  less  originally,  use  fewer  tubes 
end  consume  much  less  battery  current.  At  the  same 
time  they  give  results  not  equalled  by  receivers  costing 
a  great  deal  more  and  using  two  or  three  additional 
tubes. 

The  unique  Trirdyn  circuit — a  combination  of  Arm- 
strong Regeneration,  Radio  Frequency  Amplification 
and  Refiexed  Audio  Amplification — has  proven  beyond 
a  doubt  that  the  features  of  selectivity,  volume  and 
case  of  operation  can  be  obtained  with  three  tubes 
better  than  heretofore  has  been  possible  with  five  or 
even  six. 

Hundreds  of  voluntary  letters  have  come  to  us,  tell- 
ing of  the  unparalleled  foreign  reception  during  inter- 
national test  week  with  Trirdyns  and  all  other  Crosley 
Radios;  even  the  little  one-tube  Crosley  50  at  only 
$14.50. 

It  is  this  continued  remarkable  performance  that  has 
created  such  a  tremendous  demand  for  Crosley  Radios. 
And  it  is  this  great  popularity  that  now  allows  us  to 
decrease  our  production  costs  and  pass  this  large  saving 
along  to  '-ou. 

NEW  CROSLEY  MODELS 

In  order  to  allow  even  a  greater  selection,  three  new 
Crosley  Radios  have  been  added  to  our  extensive  line. 
Taking  its  place  with  the  well  known  Crosley  50  and 
Crosley  50-P  is  the  leatherette  covered,  one-tube  50 
Portable,  a  utility  set  in  which  the  dealer  can  quickly 
make  the  necessary  connections  and  allow  you  to  carry 
it  home  complete. 

The  New  Crosley  51  Special,  a  two-tube  receiver  sim- 
ilar to  the  Model  51,  is  housed  in  a  cabinet  large  enough 
to  hold  the  necessary  batteries  and  has  a  sloping  panel. 

Similar  to  the  Crosley  52,  but  with  sloping  panel  and 
cabinet  to  house  the  batteries  is  the  new  Crosley  52 
Special. 

These  additional  receivers  make  the  Crosley  line  abso 
lutely  complete— a  radio  for  all  tastes  and  every  pocket- 
book.     See  illustrations  for  prices. 

No  matter  what  appeals  to  you  most  in  a  radio,  you 
will  find  that  point  outstanding  in  a  Crosley. 

Most  good  dealers  handle  Crosley  Radios. 

You  Will  Make  No  Mistake  in  Buying  One. 

AU  Crosley  Receivers  contain  the  famous  Armstrong  Regenerative  cir- 
cuit, and  are  licensed  under  the  Armstrong  U.S.  Patent,  No.  1,113,149 
As  is  oustomary,  prices  show 
ipeake 
Prices  West  of  Rockies,  add  10^ 


From  a  small  beginning  three  and  a  half  years  ago, 
Crosley  Radio  has  grown  until  it  now  produces  more  sets 
than  any  other  concern  in  the  world.  The  present  produc- 
tion—nearly 5000  per  day — is  probably  from  two  to  three 
times  as   great  as  that  of  any  other  radio  manufacturer. 

Crosley  owns  and  operates  the  new  super  power  WLW 
Broadcasting  Station  located  at  Harrison,  Ohio,  remotely 
controlled  from  studios,  in  one  of  three  large  Crosley  owned 
manufacturing   plants    in    Cincinnati. 


~Jub€S  do  the  work  of[ 


Now  ^RQStE* 

TRIRDYN 


$50 


The  biggest  selling  high- 
grade  radio  on  the  mar- 
ket. Distant  loud  speaker 
reception  under  all  condi- 
tions. 


In  a  <£$$&\E{  Trirdyn 


£fr054£¥Aw 
'WRpfN'5peaal  SmQ 


Same  as  the  Trirdyn  in 
beautifully  finished  Urge 
cabinet  to  hold  the  bat- 
teries. 


Th«  loud  speaker  shown  is  the  wonderful  new  Crosley  loud  speaker  that  is  to  be  announced  in  the  near  future 

Write  for   Complete   Catalog 

THE    CROSLEY    RADIO    CORPORATION 

363  Sassafras  Street  Powel  Crosley,  Jr.,  President  Cincinnati,  Ohio 


Tested  and  Approved  by  RADIO  AGE     * 


ueprint  Section  EveryMonth 


MEET  YOUR  BROADCAST  FAVORITES 


^LONC    DISTANCE 

TRADE     MARK     REQ, 


RADIO 


Saper- Zenith  IX— 
the  ideal  radio  set 
for  the  fine  home 


* 


Every  Night  Is  "Distance  Night 

With  Zenith— 

IN  Chicago  twelve  powerful  broadcasting  stations  are  on  the 
air  every  night  of  the  week  except  Monday.  The  wave-span 
ranges  from  WBCN  (266  meters)  to  KYW  (536  meters).  No 
testing  ground  in  radio  reception  offers  the  difficulties  experienced 
in  this  location. 

But  —  whether  it's  Monday  night  or  any  other  night,  Zenith 
receiving  sets  in  Chicago  bring  in  dozens  of  distant  stations 
clearly  and  without  the  slightest  hum  of  interference  ....  and 
this  in  the  very  storm  center  of  Chicago's  broadcasting  area, 
the  near  North  Side. 

Power  to  reach  out  and  bring  in  distance — clarity  of  tone — selec- 
tivity— these  are  the  factors  which  have  made  Zenith  supreme 
in  the  field  of  radio  reception,  and  in  proof  of  that  supremacy 
Zenith  invites  and  welcomes  side-by-side  tests,  in  any  location 
you  may  name.  Its  standing  challenge:  More  stations  in  a  given 
length  of  time,  clearly  and  with  volume,  than  can  be  brought  in 
by  any  other  receiving  set  on  the  market. 

Zenith  is  handled  only  by  selected  dealers  who  give  you  service.  We  give 
the  Zenith  agency  franchise  only  to  dealers  who  will  give  you  service  AFTER 
THE  RADIO  IS  SOLD.  When  you  buy  a  ZENITH,  we  are  not  through. 
Our  exclusive  dealer's  service  man  will  call  once  a  week  or  oftener  if  you 
■want  him.  This  costs  you  nothing.  In  other  words,  Zenith  dealers  have 
done  your  shopping  for  you. 

AVrite  us  for  the  name  of  your  nearest  exclusive  Zenith  dealer 

ZENITH  RADIO  CORPORATION 

332  South  Michigan  Avenue,  Chicago 
ZENITH — the  exclusive  choice  of  MacMfllan  for  his  North  Polar  Expedition 


» 


The  complete  Zenith  line  ranges  in 
price  from  $100  to  $475. 
"With  either  Zenith  3R  or  Zenith  4R,  sat- 
isfactory reception  over  distances  of 
2,000  to  3,000^  miles  is  readily  accom- 
plished, using  any  ordinary  loud 
speaker.  Models  3R  and  4R  licensed  un- 
der Armstrong  U.  S.  Pat.  No.  1,113449. 
They  are  NON-RADIATING. 


Zenith  4R  - 
Zenith  3R  - 


$100 
$175 

The  new  Super-Zenith  is  a  six-tube  set 
with  a  new,  unique,  and  really  different 
patented  circuit,  controlled  exclusive]? 
by  the  Zenith  Radio  Corporation.  It  is 
NOT  regenerative. 

SUPER- ZENITH  VH  — Six  tubes-2 
stages  tuned  frequency  amplification  — 
detector  and  3  stages  audio  frequency 
amplification.  Installed  in  a  beautifully 
finished  cabinet  of  solid  mahogany  — 
44%  inches  long,  Va%  inches  wide,  10% 
inches  high.  Compartments  at  either 
end  for  dry  batteries.  Price  (ex-  A  ^  ^  /-\ 
elusive  of  tubes  and  batteries)  Jp^T-vJ 

SUPER-ZENITH  VTTI—  Same  as  VII  ex- 
cept— console  type.  Price  (ex-  a  -j  *zr\ 
elusive  of  tubes  and  batteries)  vf)^OvJ 

SUPER-ZENTTH  IX  —  Console  model 
with  additional  compartments  contain- 
ingbuilt-in  Zenith  loud  speaker  and  gen- 
erous storage  battery  space.  Price  {ex- 
clusive of  tubes  and  bat-  <fc  *3  C  C 
teries) Cp3j_> 

SUPER-ZENTTH  X— Contains  built-in, 
patented, Super-Zenith  Duo-Loud  Speak- 
ers (harmonically  synchronized  twin 
speakers  and  horns),  designed  to  repro- 
duce both  high  and  low  pitch  tones 
otherwise  impossible  -with  single-unit 
speakers.  Price(exclusive  of  d>  A  n  C 
tubes  and  batteries) $#  /  J 

All  Prices  F.  O.  E.  Factory. 


ZENITH  RADIO  CORPORATION,        &)  Dept.  C-4 
332  S.  Michigan  Ave.,  Chicago,  I1L 

Gentlemen:  Please  send  me  literature  describing  Zenith 
radio  sets. 

Name — 


Address ...„„..._ 


Tested  and  Approved  by  RADIO  AGE 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour  1 


I  am  averaging  anywhere  from 
$75  to  S150  a  month  more  than  I 
was  making  before  enrolling  with 
you.  I  would  not  consider  810,000 
too  much  for  the  course. 

(signed)  A.   N.   LONG. 

Greensburg,  Pa. 


No  sooner  had  I  received  my  di; 
charge  (as  a  buck  private)  than 
opened  a  radio  shop  of  my  owi 
I  earned  over  53,500  in  1  year. 
wouldn't  have  missed  the  N.  R.  '. 
course   for   a    million    dollars. 

John  P.  Zinno, 
Corona,  L.  I. 


Before  I  enrolled  with  you  I  was 
making  S15  a  week  on  a  farm. 
Now  I  earn  from  $2,080  to  $4,420 
a  year.  And  the  work  is  a  hundred 
times  easier  than  before.  Since 
graduating  a  little  over  a  year  aso. 
I  have  earned  almost  $4,000  and  I 
believe  the  course  will  be  worth  at 
least  $100,000  to  me. 

(signed)  Geo.  A.  Adams. 

Tamaqua,  Pa. 


I 


I  enrolled  with  you. 
has  benefited  me  approximately 
$3,000  over  and  above  what  I 
wouid  have  earned  had  I  not  taken 
it.  T.  Winder. 

Grand  Junction.  Col. 


Prepare  \burself  For  Radio 
— the  New  Pi-ofession 

Many  N.R.I.  Graduates  Now  Earning  From 
$5022  to  $20022  a  Week 


THE  biggest,  best-paying  field 
open  to  ambitious  men  today. 
Thousands  needed  at  once  for 
pleasant,  interesting  jobs.  High 
Pay — Short  Hours.  No  experience 
required.  Learn  in  your  spare  time 
at  home. 

Here  is  work  that  is  fascinating,  new 
and  easy — an  industry  which  is  growing 
more  rapidly  than  any  other  in  the  world 
today — an  industry  that  offers  you  the 
chance  of  a  lifetime  to  "get  in  on  the 
ground  floor"  and  make  big  money. 
Right  now,  thousands  of  trained  men  are 
needed  in  all  branches  of  the  business. 
Radio  operators,  radio  engineers,  sales- 
men, mechanics  and  Radio  executives 
are  scarce  and  receive  wonderful  pay. 
Are  you  going  to  shut  your  eyes  to  this 
golden  opportunity  when  there  is  a 
quick,  easy  way  to  get  one  of  these 
splendid  positions? 

You  can  train  for  this  "big  money" 
field  right  in  your  own  home — in  your 
spare  time.  No  matter  how  little  you 
know  about  electricity  or  Radio,  the 
National  Radio  Institute — the  largest 
and  best  school  of  its  kind  in  the  world — 
will  guarantee  to  give  you  a  thorough 
Radio  training  in  a  few  short  months. 

Salaries  Doubled   and 
Tripled 

Since  the  National  Radio  Institute 
was  founded  in  1914  over  15,000  men 
and  young  men  have  taken  this  short- 
cut to  Success  in  Radio.     They  are  en- 


Study  In  Your  Spare  Time 
At  Home 


thusiastic  about  this  wonderful  Course. 

E.  W.  Barnes,  Norfolk,  Va.,  writes: 
"During  my  spare  time,  I  make  about 
as  much  repairing  radio  sets  and  build- 
ing them  as  my  regular  salary." 

In  a  letter  from  Arthur  Ruse  of 
Toronto  we  read  that  he  has  doubled  his 
income  since  mastering  Radio  and  that 
he  earns  from  §50  to  §100  a  month  in 
his  spare  time. 

This  page  contains  only  a  few  of  the 
thousands  of  letters  we  receive  from  suc- 
cessful graduates.  Hardly  a  week  goes 
by  without  our  receiving  urgent  calls  for 
our  graduates. 
"We  need  the  ser- 
vices of  a  com- 
petent Radio  En- 
gineer." 

"We  want  men 
with  executive 
ability  in  addition 
to  radio  knowl- 
edge to  become 
our  local  manag- 
ers." "We  require 
the  services  .  of 
several  resident 
demonstrators  " 
— these  are  just  a 
few  small  indica- 
tions of  the  great 
variety  of  oppor- 
tunities open  to 
our    graduates. 

This  is  an  ab- 
solutely complete 
Radio  Course 
now  being  offered 


which  qualifies  you  for  a  Government 
First  Class  Commerci  al  L icense  and  really 
gets  you  the  bigger  paying  jobs  in  Radio. 

Send  Today  for  Free   Book  and 
Special  Short-time  Offer 

Don't  rely  on  this  announcement  for  a 
true  picture  of  the  opportunities  in  Radio. 
Simply  mail  the  coupon  and  we  will  send 
you  a  big  free  book,  "Rich  Rewards  in 
Radio,"  which  will  show  you  actual  proof 
of  the  big  money  being  made  by  our  grad- 
uates today.  It  will  describe  the  course 
in  full  detail,  it  will  tell  you  just  how  much 
you  can  earn  in  this  fascinating  profes- 


3est  of  al 


you  will  get  the  details 
of  our  Special  Reduced 
rate  which  is  being  of- 
fered for  a  short  time. 
So,  mail  the  coupon 
now!  Make  this  your 
lucky  day! 

The  National 
Radio  Institute 

Dept.  53  FB,        Washington,  D.C. 


This  is  the  time  to  go  into  radio.  Big 

opportunities  are  now  open  in  every 

branch  of  the  work,  and  salaries  were 

never  so  high.   The  thing  to  do  is  to 

begin  studying  at  once,  in  whatever 

time  you  can  spare,    ^_ 

so  that  you  will  be    | 

able   to   qualify  for        The  National  Radio  Institute 

the    position    you        D     t    53FB     Washingtorl)  D:  „ 

want  when  the  time    | 

I  am  interested  in  radio  as  a  profession.  You 
may  send  me,  free  and  without  obligation,  your 
interesting  book,  "Rich  Rewards  in  Radio," 
all  information  about  your  spare  time,  home- 
study  plan  and  about  your  free  employment 
service.    Also,  the  details  of  your  Special  Offer. 


~1 


Comes.       Only     an  j 

hour    or     so    every  | 

evening  will  quickly  j 

prepare     you     for  I 

radio — a   profession  I 

you   cannot   fail   to  I 

find  fascinating  and  j 

pleasant.        Don't  ' 

handicap     yourself;  I 

start    at    once    and  ' 

advance     with     the  | 
others. 


... Age.. 


City.. 


RADIO  AGE  for  April,  192#,  C]  B657752 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITH  WHICH  IS  COMBINED  RADIO  TOPICS 


Volume  4 


April,  1925 


Number  4 


CONTENTS 

Cover  Design  by  Fred  I.  Good 
Radio  Editorials 4 

Experiments  with  Tube  Sets 7 

By  Armstrong  Perry 

A  3-Tube  Portable  Set  for  your  Vacation.. 9 

By  H.  Frank  Hopkins 

"B"  Voltage  from  the  A.  C.  Socket ...: 11 

By  Brainard  Foote 

A  Good  Amplifier  for  the  3-Circuit  Tuner... 13 

By  Albert  E.  Sonn 

Hints  on  Proper  Wiring : 15 

By  C.  Harold  Dillon 

Regulating  Filament  Voltage 17 

65  Tried  and  True  Radio  Axioms 18 

By  Roscoe  Bundy 

Letters  from  a  Self-Made  Radio  Man  to  His  Son. ...19 
By  Edmund  H.  Eitel 

Getting  Rid  of  Squeals  and  Interference.. 21 

"The  Sleuths  of  Honeymoon  Camp:"  Conclusion.  .22 
A  Story — By  Frank  Honeywell 

"What  the  Broadcasters  are  Doing:"  RADIO  AGE 
Studio-Land  Feature  Section 23 

RADIO  AGE  BLUEPRINT  SECTION 

A  Five  Tube  "Amplex"  R.  F.  Receiver.... 35 

By  John  B.  Rathbun 

RADIO  AGE  Institute  Monthly  Tests 42 

Pickups  and  Hookups  by  Our  Readers 43 


Radio  Age  is  published  monthly  by  RADIO  AGE,   Inc. 
Member:      Audit  Bureau  of  Circulations. 


Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500   X.  Dearborn   Street,    Chicago,    111. 
Publication    Office,    Mount    Morris,    111. 

Frederick  A.  Smith,  Editor 
Russell  H.  Hopkins,  Associate  Editor 
Frank  D.  Pearne,  Technical  Editor 
C.  H.  Dillon,  Technical  Assistant 
M.  B.  Smith,  Business  Manager 

Advertising  Director 
HARRY  A.  ACKERBURG 


Eastern  Representative 
DAVIDSON"    &    HEVEY,    17  West  42nd  St. 


New  York  City 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 

preceding  date  of  issue 

Issued  monthly.     Vol.  4.     No.  4.     Subscription  price  $2.50  a  year. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris,  Illinois,  under  the 

Act  of  March  3,  1879. 


CopyripAr,  ISis,  bu  RADIO  AGE,  Inc, 


A  Chat  With 
the  Editor 

WITH  this  issue  RADIO  AGE 
enters  its  fourth  year  of  service 
to  the  radio  public.  We  are 
no  longer  a  "new"  magazine.  There 
are  only  four  other  radio  publications 
in  the  United  States  that  can  claim 
longer  life  than  RADIO  ^GE.  We 
would  hesitate  to  try  to  count  those 
which  have  come  into  the  field  since 
we  first  filled  up  our  desk  inkwell  in 
March,  1922.  Many  of  those  publi- 
cations have  budded,  burgeoned  for  a 
brief  season, and  suffered  sudden  blight. 
We  greet  our  new  and  old  readers 
with  a  word  of  appreciation  for  their 
continued  interest  in  our  efforts  and 
for  their  many  letters  of  encourage- 
ment and  approval.  We  have  made 
some  enemies  in  the  past  three  years 
and  are  proud  of  it. 

The  Radio  Corporation  of  America 
is  trying  to  wrest  from  us  the  name  of 
our  magazine  and  our  lawyers  are 
resisting  that  astonishing  attack.  The 
Radio  Corporation  wants  to  seize  our 
name  and  give  it  to  the  magazine 
which  it  owns  and  controls. 

Our  counsel  demanded  proof  of  the 
Corporation's  contention  that  our 
use  of  our  name  injures  the  business 
of  the  Corporation's  own  organ, 
Wireless  Age.  The  Corporation  there- 
upon asked  for  thirty  days  additional 
time  to  answer  our  questions.  The 
answer  of  the '  corporation  must  be 
filed  at  the  U.  S.  Patent  Office  on  or 
before  March  21st. 

On  March  18  the  corporation  also 
must  appear  before  the  Federal  Trade 
Commission  with  a  defense  to  the 
Government's  charge  that  the  Cor- 
poration is  involved  in  a  trust  con- 
spiracy. Busy  week  for  the  radio 
patriots,  we'll  say. 

It  is  possible  that  radio  fans  who 
buy  sets  and  parts  and  who  stand  for 
fair  play  and  sportsmanship  will  love 
us  all  the  more  for  the  enemies  we 
have  acquired. 

Editor  of  RADIO  AGE 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


n 


atisfactio 

Reliability 

Economy 

You  need  three  things  in  radio  "B"  Batteries — 
satisfaction,  reliability  and  economy.  You  get 
them  all  in  Eveready  ''B"  Batteries.  Satisfac- 
tion, because  they  produce  all  the  current  needed 
by  your  tubes,  giving  you  the  maximum  results 
of  which  your  set  is  capable.  Reliability,  because 
you  can  depend  on  them  to  work  at  full  power. 
Economy,  because  they  long  maintain  their 
strength,  and  because  they  are  low  in  price. 

Advances  in  the  art  of  batten-  manufacture 
make  Evereadys  last  longer  than  ever.  You 
actually  get  much  longer  service  for  your  money. 

There  is  an  Eveready  Radio  Battery  for  every 
radio  use. 

Buy  Eveready  Batteries. 

Manufactured  and  guaranteed  by 

NATIONAL    CARBON    COMPANY,    Inc. 

New  York  San  Francisco 

Canadian  National  Carbon  Co.,  Limited,  Toronto,  Ontario 

EVEREADY 

Radio  Batteries 

-they  last  lonqer 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


THERE  are  many  recent  evidences  that  the  art 
and  business  of  radio  are  approaching  a  position 
of  stabilization.  Radio  artists  are  forming  an 
organization.  Radio  announcers  in  the  East  have 
organized  an  association.  The  object  in  both  instances 
is  to  improve  the  daily  product  of  the  microphone. 

It  is  estimated  there  are  fully  10,000  entertainers 
who  go  on  the  air  each  day  in  the  more  than  500 
broadcasting  stations  now  in  operation  in  the  United 
States.  While  there  are  said  to  be  10,000,000  regular 
daily  listeners,  it  is  estimated  that  almost  25,000,000 
were  in  the  audience  that  heard  the  inaugural  cere- 
monies at  Washington  on  March  4.  This  was  accom- 
plished by  the  interconnection  of  stations  across  the 
country. 

Many  millions  are  hearing  the  Victor  and  Brunswick 
hours  of  music  at  regular  intervals.  This  access  to 
millions  of  homes  is  achieved  also  by  inter-connection 
of  stations  in  various  districts  of  the  country. 

While  the  tendency  toward  organization  is  a  healthy 
sign,  and  while  it  carries  with  it  a  promise  of  greater 
and  more  uniform  excellence  of  entertainment,  there 
is  a  danger  lest  too  extensive  a  degree  of  consolidation 
may  bring  us  nearer  to  a  monopoly  of  the  air.  This  is 
a  contingency  heartily  feared  by  thinking  radio  fans 
and  earnestly  desired  by  big  radio  interests  which 
have  dreamed  of  monopoly  since  KDKA  electrified 
the  country  with  its  first  broadcasting. 

The  American  Telephone  and  Telegraph  company, 
sometimes  alluded  to  as  one  of  the  Four  Horsemen  of 
Radio,  appears  to  have  control  of  telephone  line 
connections  whereby  trans-continental  re-broadcasts 
are  made  possible.  While  the  A.  T.  and  T.  professes 
that  the  service  of  supplying  wire  connections  with  its 
New  York  station,  WEAF,  is  rendered  impartially  and 
at  a  reasonable  cost  to  those  independent  stations 
which  desire  to  join  the  group  broadcasting,  the  writer 
is  in  possession  of  figures  which  show  that  the  charge 
for  this  service  is  by  no  means  a  nominal  one. 

Although  the  purpose  of  the  Victor  hours  of  music 
is  to  advertise  the  records  of  the  Victor  Talking 
Machine  Company  and  thereby  promote  sales  of  those 
records,  the  independent  stations  which  re-broadcast 
these  excellent  musical  features  pay  a  good  price  for 
the  privilege.  So,  it  seems,  radio  is  still  importantly 
dependent  upon  the  telephone  combine. 

IT  IS  worth  the  wrhile  of  broadcasting  interests 
throughout  the  country  to  bear  in  mind  that  any 
arrangement  which  makes  any  one,  or  even  several 
eastern  cities,  the  chief  source  of  radio  entertainment 
is  neither  the  best  arrangement  nor  in  the  long  run 
will  it  be  found  the  most  popular  one.  This  is  a  country 
of  great  distances  and  diversified  interests  and  taste. 
It  is  to  be  regretted  that  the  Chicago  Civic  Opera 
Association  could  not  have  found  it  possible  to  have 
permitted  the  broadcasting  of  solos  by  its  great  artists 
during  the  past  season.  It  is  questionable  whether  the 
broadcasting  of  complete  operas  is  always  practicable 
and  desirable  but  millions  of  music  lovers  could  have 
enjoyed  songs  from  the  Auditorium  stage.  This  would 
certainly  not  have  resulted  in  a  decrease  in  the  sale  of 
tickets  at  the  box  office.    On  the  contrary,  it  might 


have  stimulated  sales.  California  has  many  broad- 
casting stations  of  premier  excellence.  The  great  West 
has  talent  in  abundance.  One  of  the  most  significant 
phases  of  radio  is  that  it  eliminated  sectional  lines  and 
brings  North,  South,  East  and  West  into  closer  rela- 
tionship. 

HAVE  you  observed  that  it  is  now  possible  to  buy 
tubes  at  a  price  far  below  the  figures  of  a  year 
ago?  Also,  have  you  noticed  that  several  independent 
manufacturers  have  entered  the  field  with  good  tubes 
at  reasonable  prices?  Good  omens!  We  have  suspected 
recently  that  a  great  deal  of  the  current  chatter  about 
boot-leg  tubes  was  the  result  of  propaganda  instigated 
by  the  pocket  book  interests  associated  with  a  big 
corporation  which  wanted  the  public  to  buy  its  tubes 
and  no  others.  Tube  prices  were  ridiculously  high 
for  three  years.  Forcing  the  fans  to  pay  exorbitant 
prices  for  tubes  was  not  calculated  to  boost  the  popu- 
larity of  radio.  But  competition  has  now  stepped  in 
and  the  set-builder  can  buy  tubes  that  are  made  by 
independents  and  are  good  tubes  in  the  bargain.  Our 
own  technical  men  have  tested  several  kinds  of  these 
tubes  and  found  them  to  be  excellent  in  performance 
and    durability. 

A  RECENT  decision  by  a  Delaware  federal  court 
granted  an  injunction  restraining  the  Radio  Cor- 
poration of  America  from  selling  tubes  made  by  the 
Westinghouse  Lamp  Company,  a  subsidiary  of  the 
Westinghouse  Electric  and  Manufacturing  Company. 
It  appears  that  the  corporation  which  has  been  suing 
manufacturers  on  all  sorts  of  claims  of  parent  in- 
fringements was  itself  accused  in  dealing  in  tubes 
which  were  alleged  to  be  infringements  on  the  right  of 
the  DeForest  Company.  The  final  decision  in  this 
tube  suit  should  interest  the  radio  public.  It  has  its 
amusing  aspects.  Read  some  of  the  facts  about  the 
court's  decision  in  this  issue  of  RADIO  AGE. 

THE  United  States  Government  has  called  upon 
the  great  army  of  radio  fans  to  co-operate  in  what 
is  destined  to  be  the  first  real  test  of  radio  broad- 
casting in  this  country.  The  Government  asks  that  the 
fans  be  patient  while  the  super-power  tests  are  being  con- 
ducted and  to  await  results  with  an  open  mind. 

With  the  first  announcement  that  "super"  or  in- 
creased power  was  to  be  tried  out,  there  was  some 
grumbling  on  the  part  of  fans  living  near  the  proposed 
super-power  locations.  They  complained  they  would 
not  be  able  to  hear  anything  once  the  strong  stations 
got  on  the  air.  They  looked  upon  the  super-stations 
as  a  just  cause  to  junk  their  receiving  sets. 

The  Government  does  not  take  this  stand.  If  the 
super-stations  make  it  impossible  for  fans  to  hear 
anything  else,  it  has  been  explained,  they  will  not  be 
licensed  permanently.  The  thing  to  be  remembered 
at  this  time  is  that  present  super-power  operations 
are  purely  experimental  and  not  definite.  The  minute 
the  Government  finds  these  stations  are  detrimental  to 
the  welfare  of  radio,  they  will beabolished.Thisisaprom- 
ise ;  and  our  country  usually  lives  up  to  its  promises. 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Now  Yon  Can  Afford  — 

a  modern  precision-made 
set  which  "cuts  through" 

((  Tuned  radio  frequency  for  distance  and  selectivity,  reflex 
for  economy,  the  unequaled  loudspeaker  tone  quality  and 
volume  which  comes  with  Ali/ American  precision  manu- 
facture—all are  present  in  this  non^radiating  three'tube 
receiver.  ((And,  owing  to  the  economy  of  "wiring  it  your' 
self,"  All'Amax  Senior  costs  less  than  a  finished  one 
tube  set  of  equally  high  quality.  ((  Ta\e  it  home  today  from 
your  favorite  radio  store;  wire  it  this  evening,  and  "tour 
the  country"  before  you  retire  for  the  night!  Price  $42. 

The  RADIO  KEY  BOOK  has,  concentrated  in  its  48  pages,  the  an- 
swers to  those  questions  you  have  been  wondering  about.  It  is  a  radio 
education  in  itself.   Send  ten  cents,  coin  or  stamps,  for  your  copy. 

ALL-AMERICAN  RADIO  CORPORATION 

PIONEERS  IN  THE   INDUSTRY 
2680  Coyne  Street         -         -         -         Chicago 


Guaranteed 
Radio  Products 

Standard  Audio  Transformers 
3to  1  Ratio,  typeR-12...  $4.50 
5 to  1  Ratio,  typeR-21...  4.7S 
10  to  1  Ratio,  type R- 13...  4.75 

Power  Amplifying  Transformers 
(Push-Pull) 

Input  type  R-30 $6.00 

Output  type  R-31 6.00 


Rauland-Lyric 

A  laboratory  grade  audio 
transformer  for  music, 
lovers.  R-500 $9.00,1 

Universal  Coupler 
Antenna  coupler  or  tuned  r.  f . 
transformer.    R-140 $4.00 

Self-Tuned  i  *A*|A 

R.  F.  Transformer  /*"""  |K 
Wound  to  suit  the  \=&^Z&U 
tube.  R-199$5.00.  R-201A$5.00 

Long  Wave  Transformer 

(Intermediate  Frequency) 

(15-75  kc.)  R-110 $6.00 


10,000  Meter(30kc.) 

Transformer 
Tuned  type  (filter  or 
input). R-120.. $6.00 


Radio  Frequency  Coupler 
(Oscillator  Coupler).  R-130  $5.00 


Super-Fine  Parts 
Consisting  of 
three  R-110's, 
one  R-120  and 
one  R-130  $26.00 


The 
ALL-AMAX 

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A  one-tube  reflex  set 
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Price  $22 


All  American 

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*     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Silver-Marshal!  me 

W0  RADIO    11        EQUIPMENT 


Silver 

Supers 

Approved 

by  the 

"Who's  Who" 

of  Radio 


Coast 

to 

Coast 

with  Speaker 

Volume 

on  a  Loop 


DESCRIBED  LAST  MONTH  IN  RADIO  AGE  AS 


A  RECEIVER  THAT  WILL  SERVE  FOR  YEARS 


SILVER  SUPERS 

Embody  the  Latest  In  Radio 


* 


THE      FACTS 

TJASIC  FACTS  make  Silver  Supers  the  logical 
*-*  selection  of  the  man  who  wishes  to  build  the 
best.  Briefly  enumerated  these  facts  are:  The  uni- 
versal endorsement  of  the  leading  authorities  in 
Radio — the  unsurpassed  reception  records  set  by 
Silver  Supers  —  S-M  Two-Ten  and  Two-Eleven 
matched,  tested  and  charted  Transformers — the 
admitted  correctness  of  the  principles  embodied 
in  the  design — simplicity  of  construction  and  the 
low  cost.  For  the  man  who  wants  to  build  his  own 
Receiver,  and  who  wants  to  build  the  best  for  years 
of  use,  there  is  just  one  set.  .  .  .  the  SILVER 
SUPER. 


APPROVED 

THE  LIST  of  those  who  have  endorsed  Silver  Supers 
very  nearly  constitutes  the  "WHO'S  WHO"  of 
Radio.  Approval  is  thunderous  when  it  includes 
these  experts:  Arthur  H.  Lynch  of  Radio  Broadcast, 
Capt.  John  Irwin  of  Radio  Broadcast's  "Covered 
Wagon,"  Gerald  M.  Best,  Technical  Advisor  of  Radio 
Magazine,  M.  B.  Sleeper  of  Radio  Engineering, 
Frank  D.  Pearne  of  Radio  Age,  Iverson  C.  Wells  of 
Everybody's  Radio,  and  R.  E.  Hughes  through  his 
six  Newspapers.  Add  the  Chicago  Herald  and  Ex- 
aminer, American  Radio  Journal,  Citizens  Radio 
Call  Book,  On  the  Air  Magazine,  and  the  cautious 
Christian  Science  Monitor  and  WTAS  Broadcasting 
Station  .  .  .  then  you  will  know  that  Silver  Supers 
have  been  approved  by  the  "WHO'S  WHO"  of  Radio. 


BUILD  YOUR  OWN— it's  easy— GET  THESE  PARTS 

LABORATORY  MODEL  Each  LABORATORY  MODEL.  (Cont.) 


Price 
Each 

2  Silver  .0005  Low  Loss  Condensers  No.  301 $4.50 

2  4  in.  Moulded  Dials — Tapered  Knobs 1.00 

1  U.S.  L.  7  Ohm  Rheostat 1.10 

1  U.  S.  L.  240  Ohm  Potentiometer 1.50 

7  Insulated  Top  Binding  Posts 05 

1  Carter  102 A  Jack 80 

1  Carter  101  Jack 70 

2  210  Transformers 8.00 

1  211  Transformer 8.00 

lfSilver  Oscillator  Coupler  No.  101 2.50 

7  Benjamin  Spring  Sockets  (199  or  201A?) 1.00 


Price 
Each 

2  Thordarson  3  1-2:1  Audio  Transformer 4.00 

1  On-off  Switch 60 

3  .5  MFD  By-pass  Condensers 90 

2  .00025  Mica  Condensers  with  Leak  Clips 45 

I   .002  Mica  Condensers 40 

1   .000045  Balancing  Condensers 150 

1   5  Meg  Ohm  Grid  Leak 50 

1    1  Meg  Ohm  Grid  Leak 50 

1  7x24x3-16  in.  Bakelite  Panel,  Drilled.Grained  and  Engraved      7.00 

(Specify  with  or  without  meter  hole.) 
1  7x23x1-2  in.  Oak  Base  Board,  Bus-Bar,  Spaghetti,  Screws 

Nuts.  Solder,  Lugs 1.50 


Complete  Parts  for  the   Silver   Super — Laboratory  Model,  $63.60 

Laboratory  Model  Blue  Prints,  50c 

McMurdo  Silver's  Book,  "THE  PORTABLE  SUPER-HETERODYNE.  50c 


S-M  TWO  TENS  and  TWO  ELEVENS 

Long  Wave  Transformers  supplied  in 
sets  of  two  or  three  Two  Tens  (iron- 
core  interstage)  and  one  Two  Eleven 
(filter  for  input  or  output)  with  iden- 
tical peaks  and  separate  curves. 
Curves  plotted  in  our  own  Laboratory 
and  recorded  directly  on  the  trans- 
former's tag.  Both  peak  at  5000  me- 
ters and  pass  an  11  Kilocycle  sideband 
without  distortion. 
Price  of  either  type  each $8.00 


S-M  DISTORTIONLESS 
AUDIO  AMPLIFIER  gives 
perfect  tone  quality  on  all 
vocal  and  orchestral  music, 
and  that  with  greater  vol- 
ume. The  cost  is  no  more 
than  that  of  ordinary  trans- 
former coupled  amplifiers. 
Price  each $17.95 


S-M  LOW   LOSS    CONDENSER 

Type  301,  straight  line,  low  loss, 
grounded  rotor  condenser  of  the 
most  approved  and  advanced 
design.  For  maximum  effici- 
ency, the  Silver  Low  Loss  Con- 
denser should  be  used  in  the 
4-Tube  Knockout,  and  all  sets 
where  extreme  efficiency  is  de- 
sired. Cap.  .0005  Mfd. 
Price  each $4.50 


4-TUBE    KNOCKOUT   on  a 

70-foot  antenna  will  equal 
the  startling  performance 
of  the  Silver  Supers.  Send 
for  McMurdo  Silver's  own 
description  of  this,  his  latest 
circuit.  It  contains  a  wealth 
of  information  and  com- 
plete assembly  instructions. 
Price 25c 


GUARANTEE— Every  S-M  Product   is  sold   on   the 
Satisfaction  or  your  money-back  basis. 

Eastern  Distributor 

TWENTIETH  CENTURY 
RADIO  CORP., 

102  Flatbush  Ave.         Brooklyn,  N.  Y. 


WRITE    for    illustrated    Literature    describing    the 
latest  developments  in  Radio. 


Silver-Marskali 
RADIOll        EQUIPMEI 


110  So.  Wabash  Ave. 


ma 

S  Q  U I P  M  EN  T 

CHICAGO 


*     Tested  and  Approved  by  RADIO  AGE     * 


MAY -7  75 


RADIO  AGE  for  April,  1925 

=)BD 


The  Magazine  of  the  Hour 
1BE 


JSq  Magazine  ftho  Hour 


M.  B.  Smith 

Business  Mana 


A   Monthly     Publication 

Devoted  to  Practical 

Radio 


Frederick  A.  Smith 
Editor 


B 

G=>BG 


3EE 


3DE 


3SE 


SHE 


3EE 


E3EG 


e 

30r==H 


Something  for  the  Experimenter — 

Teste  m  Circuit  JUGGLING 


THERE  has  been  considerable  re- 
duction in  the  prices  of  radio 
receivers,  but  it  may  be  news  to 
some  fans  that  it  is  possible  to  secure 
electron  tube  sets  as  low  as  one  dollar  per. 
It  has  been  done  and  you  can  do  it. 

The  examination  of  a  hundred  single- 
tube  hook-ups  shows  that  many  contain 
the  same  or  similar  parts.  Reading  a 
diagram  from  left  to  right,  the  first  thing 
encountered  is  an  inductance  coil.  There 
may  be  two  or  three.  If  two,  they  may 
be  in  a  variometer  or  a  variocoupler.  If 
three,  one  of  them  is  usually  a  tickler. 

Following  the  path  of  the  antenna 
current  toward  the  grid,  we  find  a  grid 
condenser  shunted  by  a  grid  leak.  Trac- 
ing the  course  of  the  output  from  the 
plate,  we  pass  the  tickler,  if  there  is  one, 
the  phones,  and  the  "B"  battery.  In 
the  filament  circuit  there  is  an  "A" 
battery  and  a  rheostat  to  regulate  its 
supply  of  current  to  the  filament. 

Anyone  who  will  write  on  a  piece  of 
paper  the  names  of  the  parts  used  in  one- 
tube  receivers  will  be  surprised  that  they 
are  so  few.  The  ordinary  regenerative 
and  non-regenerative  circuits  can  be  built 
with  about  a  dozen  pieces  of  apparatus. 
Even  the  reflexes,  with  their  amplifying 
transformers,  require  no  more  than  fifteen 
to  twenty.  It  follows,  therefore,  that  as 
many  as  twenty-five  different  hook-ups 
can  be  made  from  the  same  parts,  merely, 
by  arranging  them  according  to  different 
diagrams.  A  complete  set  of  parts  that 
may  be  assembled  into  as  many  as 
twenty-five  different  hook-ups  can  be 
purchased  for  S25.00.  It  follows,  there- 
fore, that  the  cost  per  receiver  is  but  one 
dollar.  Moreover,  the  parts  can  be  so 
mounted  and  connected  that  the  con- 
nections can  be  changed  in  a  few  mo- 
ments, giving  the  operator  any  one  of  the 
circuits  that  he  has  the  parts  for,  so  he 
actually  may  have  under  his  hand  the 
whole   twenty-five   receivers. 

Honeycombs  Are  Good 

MENTION  honeycomb  coils  and  some 
dealers  and  fans  immediately  cry 
"Obsolete!"  Let  them  shout.  They  have 
failed  to  follow  the  example  of  the  busy 
little  bee,  inventor  of  honeycomb,  who 
knows  enough  to  stick  to  a  good  thing 


By  ARMSTRONG  PERRY 

25  Hookups  Possible 
with  But  a  Few  Parts 


when  he  finds  it.  Modern  business  has 
discovered  that  nothing  moves  so  many 
goods  as  fads.  Since  fads  are  short-lived, 
it  is  necessary  to  create  a  new  one  as 
often  as  possible.  Honey-comb  coils  were 
once  a  fad.  They  work  just  as  well  now 
as  they  did  then.  Probably  they  will 
work  even  better,  when  used  with  some 
new  types  of  apparatus.  Government 
tests  proved  that  on  short  waves  they 
were  not  so  efficient  as  on  wavelengths 
above  1,000  meters,  but  it  is  possible  to 
purchase  straight-wound  short-wave  coils 
of  the  same  dimensions  and  values  as 
honeycombs,  similarly  mounted  and  in- 
terchangeable. 

So  if  you  want  to  do  some  experiment- 
ing that  will  increase  your  store  of  radio 
knowledge  and  afford  you  some  pleasant  as 
well  as  instructive  hours  in  addition,  we 
suggest  that  you  get  a  three-coil  mounting 
and  some  coils  and  use  them  as  the  in- 
ductance in  your  one-dollar  receivers. 

It  is  not  necessary  to  buy  all  sizes  of 
coils.  Secure  a  catalogue  that  shows  the 
wavelengths  covered  by  coils  of  different 
sizes  and  you  will  see  that  the  wavebands 


A  front  view  of  one  of  the  experimental 
models  built  by  Mr.  Perry.  Remarkable 
distance  and  selectivity  have  been  achieved 
with  these  simple  sets. 


overlap.  When  shunted  by  a  .001  con- 
denser, a  25-turn  coil  will  cover  the 
wavelengths  used  by  amateur  radio  teleg- 
raphers, a  50-turn  coil  most  of  the  band 
used  by  the  broadcasters,  a  100-turn  coil 
the  higher  broadcasting  wavelengths  and 
the  ship-to-shore  traffic.  If  you  want  to 
go  on  up  to  the  Army  and  Navy  wave- 
lengths, or  pull  in  the  trans-oceanic 
traffic  from  the  high-power  stations, 
larger  coils  may  be  selected.  The  con- 
denser, if  connected  in  series  with  a  coil, 
will  reduce  its  wavelength.  If  mounted 
so  that  the  turn  of  a  switch  will  change 
the  connection  from  series  to  parallel,  or 
vice  versa,  it  will  have  the  maximum 
adaptability. 

The  three-coil  mounting  with  from 
three  to  six  coils  takes  the  place  of  many 
pieces  of  apparatus.  The  variometers 
and  variocouplers  made  with  a  tube  for 
a  stator  and  a  ball  for  a  rotor  have 
become  so  popular  that  it  has  been  almost 
forgotten  that  the  main  thing  in  such 
apparatus  is  the  control  of  the  positions 
of  the  windings  with  respect  to  each 
other.  When  parallel,  they  give  the 
maximum  inductive  effect.  When  at  right 
angles  to  each  other,  they  give  the 
minimum  inductive  effect.  A  coil  swung 
on  a  hinge  can  form  just  as  many  angles, 
with  respect  to  an  adjacent  stationery 
coil,  as  one  turned  on  a  ball.  The  tube- 
and-ball  variometer  and  variocoupler 
have  one  advantage  over  the  hinge  type 
in  that  they  keep  all  the  windings  closer 
together  at  all  settings,  so  experts  choose 
them  when  a  highly  efficient  piece  of 
apparatus  is  needed  to  cover  a  certain 
restricted  range  of  wavelengths. 

Covers   Wide   Band 

HOWEVER,  we  cannot  expect  every- 
thing in  a  dollar  outfit,  and  though 
the  three-coil  mounting  may  not  de- 
velop the  highest  efficiency  at  every  wave- 
length, it  is  generous  in  the  width  of  the 
band  that  it  covers.  Even  if  a  single-coil 
circuit,  such  as  the  ultra-audion,  is  being 
used,  you  can  yank  out  your  25-turn  coil 
when  the  jargon  of  the  hams  becomes 
unbearable,  plug  in  a  1500-turn  coil,  and 
immediately  soothe  your  irritation  by 
listening  to  the  smooth,  rhythmic  send- 
ing of  the  big  commercial  stations.  Or, 
if  local  broadcasting  stations  are  fighting 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


A  back  view  of  one  of  the  $1.00  receivers.  Notice  the  adjustable  grid  leak  and  the 
three  honeycomb  coils  which  efficiently  received  ship-to-shore  traffic  when  the  set  ivas 
plugged   into   an   electric   light   socket  in  Chicago. 


each  other  for  the  right  of  way  down  your 
antenna,  a  quick  shift  of  coils  may  rid 
you  of  all  but  one.  A  dozen  single-coil, 
variometer  and  variocoupler  hook-ups 
can  be  tested  in  a  single  evening. 

Portability,  also,  is  within  your  reach 
with  such  an  outfit.  There  are  condensers, 
hard  to  find  but  in  the  market,  that  have 
the  capacity  of  a  43-plate  contraption  in 
less  than  one-fourth  the  space.  They  are 
equally  variable  and  have  dials  like  the 
big  condensers.  Rheostats  come  in  many 
sizes  and  shapes.  Small  parts  like  the 
grid  leak  and  condenser  can  be  squeezed 
in  anywhere.  A  cigar  box  cover  is  large 
enough  to  mount  the  whole  outfit.  By 
judicious  selection  of  two  cigar  boxes, 
you  can  secure  as  a  panel  a  cover  that 
will  fit  snugly  into  the  other  box.  When 
such  an  oufit  is  finished,  it  should  be 
plainly  marked  "Radio"  to  avoid  dis- 
appointing one's  friends.  If  a  Pittsburgh 
stogie  box  is  used,  this  precaution  is  un- 
necessary, for  no  one  would  think  of 
raising  the  cover  anyhow. 

There  are  a  few  fine  points  to  remem- 
ber when  purchasing  parts.  If  you  want 
a  portable  set,  you  will  need  a  tube  that 
will  operate  on  dry  cells.  Each  type  of 
tube  has  its  own  characteristics.  One 
may  work  very  well  with  a  1-megohm 
grid  leak  and  another  may  work  better 
with  from  3  to  5  megohms.  A  variable 
grid  leak  will  fit  any  tube,  and  is  even 
better  than  a  handful  of  the  cheaper  leaks 
of  different  fixed  resistance  values.  A. 
variable  grid  condenser  increases  the 
elasticity  of  the  set  also. 

A  dozen  wires  of  various  lengths,  made 
up  with  clips,  lugs  or  other  convenient 
devices  on  both  ends,  will  save  much 
time  in  changing  connections.  Small 
switches  may  be  installed  at  points  where 
many  and  quick  changes  may  be  desired. 

Satisfactory  DX 

How  far  can  you  hear  with  such  an 
outfit?  That  is  usually  the  first  thing  a 
beginner  wants  to  know.  The  first  hook- 
up I  used  was  a  combination  of  ultra- 
audion  and  Colpitts  circuits,  using  a 
single  coil.      I   was  in   Chicago  and  the 


outfit  exhibited  a  splendid  loyalty  to  the 
home  talent.  It  kept  KFI  at  a  distance 
and  did  not  give  WEAF  a  Chinaman's 
chance  to  interfere.  As  there  was  no 
local  code  traffic,  it  cheerfully  brought  in 
ship-to-shore  messages  from  the  Atlantic 
seaboard,  and  the  time  signals  from  NAA. 


Here  is  another  of  the  hookups  built 
with  the  "$1.00  circuit"  by  Mr.  Perry. 
This  hookup  differs  from  the  one  shown 
on  Page  7  in  that  only  one  coil  is  used. 
This  arrangement  insures  excellent  long- 
distance broadcast  reception. 

In  New  York  and  Washington  whence, 
because  of  its  lightness  and  small  bulk 
it  was  easy  to  carry  it,  it  quickly  forgot 
the  city  of  its  birth  and  turned  a  deaf  ear 
to  WLS  and  all  the  rest  of  the  Chicago 
stations.  However,  I  have  friends  with 
hundreds  of  dollars  tied  up  in  sets  that 
operate  within  the  broadcasting  wave- 
band only,  who  cannot  get  out-of-town 
stations  without  going  where  they  are. 

Selectivity?  Well,  it  did  not  seem  to 
want  to  miss  anything  that  was  going  on 
locally.  But  on  a  farm  or  in  a  town  a 
hundred  miles  from  the  nearest  broad- 
casting station,  it  would  separate  cleanly 
stations  with  wavelengths  reasonably  far 
apart,  if  carefully  tuned.  In  tuning,  the 
separation  of  the  coils,  the  adjustment  of 
the  variable  condenser,  the  fine  control 
of  filament  current,  the  accurate  setting 


of  the  grid  leak  and  condenser,  all  played 
important  parts,  as  well  as  the  selection 
of  coils. 

Taken  by  and  large,  an  investment  of 
$25.00  in  such  an  elastic,  portable,  ex- 
perimental outfit,  yields  the  largest 
dividends  in  radio  fun  and  experience  of 
any  I  ever  made. 

Keep  Connections  Straight 

T  TSE  flexible  wire  in  making  the  con- 
*—  nections,  and  keep  them  short  and 
straight.  If  j^ou  care  to,  you  can  use 
stranded  wire,  with  clips  on  the  ends. 
This  will  enable  you  to  change  over  from 
one  circuit  to  the  other  very  rapidly. 

Of  course,  the  resistance  will  be  quite 
high  and  the  results  will  not  be  as  good. 
But  for  experimental  purposes  it  answers 
quite  well.  Using  that  system,  it  is 
possible  to  wire  almost  any  circuit  in 
about  twenty-five  minutes. 

After  you  have  tried  a  great  many 
hookups  with  your  $25  layout  you  may 
wish  to  tie  to  one  of  them,  in  which 
event  be  sure  to  solder  all  connections 
carefully,  making  the  leads  as  short  as 
possible  and  you  will  have  no  cause  to 
regret  the  time  or  money  spent.  Care 
in  the  use  of  soldering  paste  or  flux  will 
return  the  usual  dividends. 

The  standard  three  honey-comb  coil 
hookup  will  be  found  to  be  the  best  and 
the  most  selective.  Signals  from'  a  long 
distance  and  signals  from  stations  whose 
wavelengths  are  about  the  same  can  be 
separated  quite  easily. 

This  method  of  tuning  seems  to  be 
forgotten  in  the  present  days  of  "dynes" 
and  "supers,"  but  nevertheless,  it  is  very 
efficient. 

Consider  the  number  of  three  circuit 
tuners  on  the  market,  whose  principle  is 
exactly  the  same  as  the  tuning  of  the 
standard  three  honey-comb  coil  system. 

(Many  fans  will  no  doubt  try  their  hick 
at  building  several  of  the  twenty-five  hookups 
possible  with  Mr.  Perry's  unique  arrange- 
ment of  parts.  RADIO  AGE  will  print 
your  hookup  from  the  apparatus  specified 
if  you  will  send  your  data  to  the  "Pickups 
and  Hookups"  Editor.) 


Above  is  the  third  hookup  the  experi- 
menter may  construct  from  very  few  parts. 
This  employs  a  primary  of  the  aperiodic 
type  which  increases  selectivity  to  a  great 
extent.  While  it  does  not  achieve  pheno- 
menal results  in  DX  work,  it  is  unusually 
satisfactory  in  a  big  city  where  there  are  a 
number  of  broadcasters. 


RADIO   AGE  for  April,  1925 


The  Magazine  of  the  Hour 


AThreeTube  Wk  PortableSet 
for  Your  ill  Vacation 


By 
H.  FRANK 
HOPKINS 


Include  a  Portable  Set  in  Your  Traveling  Equipment 
This  Summer  and  Your  Joys  Will  be  Unlimited 


Have  you  seen  Cod  in  His  splendors, 
Heard  the  text  that  nature  renders? 
(You'll  never  hear  it  in  the  family  pew., 
The  simple  things,  the  true  things, 
The  silent  men  who  do  things — 
Then  listen  to  the  Wild — 
It's  calling  you.  (Service) 

YOU,  among  the  rest  of  us,  no  doubt, 
are  getting  restless  and  looking 
forward  to  summer  and  the  annual 
two  *weeks.  A  sort  of  dreamy  feeling 
creeps  over  you  and  work  seems  out  of 
the  question.  The  fishing  tackle  is 
looked  over;  the  golf  clubs,  perhaps,  or 
the  camping  outfit  are  also  inspected. 
An  increasing  demand  for  time  tables 
and  road  maps.  All  are  symptoms  of 
that  disease,  that  contagious  malady  of 
April  and  May — "Spring  Fever." 

Have  you  stopped  'long  enough  to 
think  what  an  added  pleasure  it  would 
be  to  take  the  radio  along  this  time? 
Remember  the  evenings  around  the  old 
camp  fire,  telling  the  fish  stories  and 
reciting  the  day's  adventures?  Or  maybe 
it  is  at  the  sea-shore,  those  long  remem- 
bered hours  that  seem  like  minutes  when 
you  live  them  over  again.  How  nice  it 
all  was,  and  how  much  more  you  would 
have  enjoyed  it  if  you  had  had  the  old 
winter's  stand-by,  your  radio,  along  to 
furnish  music  to  sing  to,  to  dance  to  or 
just  to  listen  to. 

A  Real  Companion 

["  ET  us  include  a  radio  this  time  and 
-"  see  how  different  it  will  all  seem, 
to  be  out  iii  the  great  open  spaces,  far 
from  the  rush  and  din  of  the  hot,  dusty, 


city,  with  just  the  sky,  your  pal  and  the 
radio.  Real  music,  the  news  of  the  day, 
and  for  the  business  man,  the  market 
reports,  all  at  your  finger  tips.  Don't 
you  think  it  would  be  worth  a  trial? 
I  took  mine  last  year  and  that  will  be 
my  first  thought  this  time  and  all  of  those 
to  follow.  I  am  going  to  describe  the 
set  I  used  so  you  too  can  take  one  this 
year  to  give  you  as  much  pleasure  as 
mine  gave  me. 

The  first  thing  to  look  for  in  a  set 
such  as  this  is  simplicity,  compactness 
and  weight.  It  must  be  simple  to  oper- 
ate, simple  to  build,  compact  and  port- 
able, and  as  light  as  can  be,  requiring  as 
small  an  antenna  as  possible  and  be  as 


,  ..  £>£Ti1/LS     TO  6S    AT/)D£ 

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Mr 


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Above  is  shown  the  method  of  making 
the  brackets  for  the  3-tube  portable  set 
described  in  this  article. 


sturdy  as  it  can  be  to  withstand  all  of 
the  knocks  and  abuse  it  will  get  in  moving 
from  place  to  place.  Not  an  elaborate 
set;  just  a  moderate-priced,  good,  sub- 
stantial receiver  with  batteries  and  loud 
speaker  self  contained. 

The  next  step  will  be  to  secure  a  good 
strong  grip  such  as  used  for  school  books, 
the  inside  measurements  should  be  at 
least  eighteen  inches  long,  twelve  inches 
high  and  five  inches  deep.  This  should 
be  given  a  few  coats  of  waterproof 
varnish  and  allowed  to  dry  thoroughly 
to  make  it  as  moist-proof  as  possible, 
to  prevent  warping. 

When  the  grip  is  prepared,  the  panel 
can  then  be  laid  out  and  the  various 
brackets  and  straps  made,  and  put  aside 
until  the  set  has  been  built  and  is  ready 
to  mount. 

The  most  difficult  task  in  the  construc- 
tion of  this  set  will  be  to  properly  arrange 
the  parts  to  conserve  space.  The  dia- 
gram shown  in  figure  two  will  greatly 
lessen  this  task,  as  it  can  be  followed  for 
almost  any  size  case  over  that  described. 
Some  may  want  to  place  the  parts  in  a 
different  manner;  if  so,  care  should  be 
taken  to  see  that  the  tuning  element  is 
as  far  away  from  the  audio  transformers 
as  possible,  and  that  the  tubes  are  so 
placed  that  they  can  be  removed  easily, 
as  it  is  a  good  plan  to  take  them  out 
and  carry  them  in  their  original  boxes 
while  transporting  the  set  from  place 
to  place,  as  a  tube  can  be  very  easily 
damaged  by  sharp  jolts  and  rough 
handling  when  in  a  rigid  fixture,  such  as 
a  socket. 

The  next  step  will  be  to  make  the  two 


10         RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


A  rear  view  of  the  tuner  for  Mr.  Hopkins' 
portable  set,  showing  the  method  of  mount- 
ing the  coils  on  the  back  of  the  condenser. 

(Radio  Age  Photo) 

spider-web  coils.  This  is  about  one  of 
the  most  simple  and  fool-proof  coils 
lor  the  fan  to  build.  There  is  less  chance 
to  go  wrong  and  less  mechanical  skill 
is  required.  It  is  also  one  of  the  most 
efficient  of  low  loss  coils.  The  only 
thing  necessary  to  wind  this  coil  is  a 
spider  frame  having  about  fifteen  spokes. 
This  may  be  purchased  at  a  cost  of  about 
twenty-five  cents  at  any  reliable  dealer. 

Winding  the  Coils 

T I  ''HESE  coils  should  be  wound  in  a 
■*-  clockwise  direction,  leaving  about 
six  inches  of  free  end  for  each  connection. 
They  will  be  wound  over  two  spokes 
and  under  two  spokes  as  described  in 
the  article  on  the  De  Luxe  receiver 
published  in  the  February  issue  of 
RADIO  AGE.  One  of  the  coils  will  be 
wound  with  eighteen  turns  of  number 
twenty-four  B  and  S  gauge,  double  silk 
covered,  copper  magnet  wire,  the  other 
coil  will  consist  of  sixty-eight  turns  of 
the  same  wire.  When  one  coil  is  finished, 
it  should  be  treated  with  a  good  solution 
of  collodium  and  allowed  to  dry  thor- 
oughly  and   the   spokes   removed.      The 


SECTION 'AL      VI  EH 

SC£     NOTE 

B 


The  top  view  shows  the  connections  for  the  "A" 
and  "B"  Batteries  and  the  method  of  fastening  them 
in  place.  The  Loud  Speaker  is  shown  mounted  in 
the  panel   but  may  be  omitted   if  desired. 


The  sectional  view  shows  the  method  of  mounting 
the  panel  in  the  case  and  the  placing  of  the  wood 
strips  to  form  the  Battery  Compartments  and  the 
stTaps   fcr   fastening  the    Batteries    in   place. 


TOP    VIEW 
see  hotc 


FIGUZE   Z 


"TY'ifl 


edges  of  this  coil  will  then  be  given  a 
good  coat  of  collodium  to  prevent  the 
wires  from  coming  loose  or  it  may  be 
sewed  >vith  silk  thread. 

The  second  coil  will  be  built  up  in 
the  same  way  and  the  two  coils  will 
then  be  securely  fastened  together  as 
shown  in  the  picture  of  the  tuning  unit 
on  page  10.  This  may  be  done  *ith 
collodium,  also,  or  they  may  be  sewed 
together  or  even  glued.  The  completed 
coil  unit  will  then  be  mounted  on  the 
condenser  and  connected.  One  side 
of  the  secondary  coil  will  connect  to  the 
rotor  plates  of  the  condenser  and  the 
other  side  to  the  stator,  or  stationary 
plates  and  the  tuning  element  is  com- 
pleted and  ready  to  mount  on  the  panel. 
The  bracket  shown  in  figure  three,  as 
detail   one.    will   be   used   to    mount   the 


coil  and  should  first  be  covered  with 
friction   tape  or  other  good  insulator. 

The  panel  will  now  be  prepared. 
The  instruments  should  be  placed  around 
until  they  are  satisfactorily  arranged, 
their  mounting  holes  marked  and  the 
panel  drilled.  A  hole  about  one-half  inch 
in  diameter  should  be  drilled  for  the 
shaft  of  the  tuning  element  and  three 
holes  to  pass  the  shells  of  the  tube  sockets. 
These  sockets  will  be  mounted  on  the 
under  side  of  the  panel  with  the  shell 
projecting  through  to  the  top.  A  three 
gang  socket  may  be  used  if  desired,  as  it 
is  more  suitable  for  this  type  of  mount- 
ing. 

All  of  the  equipment  will  be  mounted 
on  the  back  of  the  panel,  as  there  is  not 
sufficient  room  for  a  shelf.  This  will 
(Turn  to  page  67) 


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The  Magazine  of  the  Hour        1 1 


RADIO  AGE  for  April,  1925 

Getting  fcW£T  Voltage  with  an 

A.  C.  RECTIFYING  System 


BY  BRAIN ARD  FOOTE 


The  photograph  shows  the  main  parts 
of  a  simple  A.  C.  rectifier.  The  trans- 
former is  one  of  the  ordinary  audio  fre- 
quency type.  The  tungar  bulb  is  one  of  the 
five    ampere    type. 


TV  "I  OX-TECHXICAL  men  who  have 
^^  been  interested  in  radio  have 
■J-  '  often  asked  just  why  it  was  that 
the  necessary  voltage  for  the  plate 
circuits  of  our  amplifying  tubes  could 
not  be  secured  from  the  unchanging  and 
reliable  source — the  lamp  socket.  Of 
course,  in  those  few  city  locations  where 
the  lighting  circuits  are  furnished  with 
direct  current,  this  is  a  comparatively 
simple  matter,  but  inasmuch  as  the  vast 
majority  of  us  have  A.  C.  instead,  the 
problem  isn't  quite  so  easy. 

Naturally,  the  alternating  voltage  will 
not  do  of  itself,  since  the  reversals  of 
polarity,  taking  place  120  times  every 
second,  cause  what  is  called  a  "60  cycle" 
hum,  so  loud  as  to  utterly  ruin  broadcast 
music  or  voice.  It  therefore  becomes 
necessary  to  convert  or  change  this 
alternating  voltage  into  a  steady  voltage 
— to  change  the  alternating  current  into 
direct  current. 

To  perform  this  feat  a  "rectifier"  is 
employed.  The  rectifier  is  any  device 
which  permits  current  to  pass  in  one 
direction  more  readily  than  in  the  other, 
thus  leaving  a  "balance"  of  voltage  which 
is  always  in  the  same  direction.  The 
more  nearly  perfect  the  rectifier,  the 
more  Tiearly  does  it  exclude  all  current 
in  the  reverse  direction.  The  familiar 
crystal  detector  is  a  rectifier,  but  hasn't 
the  current  carrying  power  or  the  ap- 
proach to  perfection  that  is  necessary 
for  "B"  rectification.  A  good  rectifier 
may  be  formed  of  a  collection  of  jars 
containing  a  lead  electrode  and  an  alumi- 
num electrode,  dipping  into  a  solution  of 
borax.  This,  while  feasible,  is  messy 
and  too  much  of  a  nuisance  for  general 
satisfaction. 

The  Vacuum  Tube 
HPHE  most  perfect  rectifier  known  is 
-*-  the  vacuum  tube  itself.  Although 
not  looked  on  exactly  in  this  light,  there 
are  tubes  used  as  rectifiers — as  witness 
the  tungar  battery  charger  that  uses  a 
large  tube  containing  a  filament  and  a 
plate  for  the  rectifying  work.  In  Fig.  1 
we  find  the  principle  of  a  tube  rectifier 


A  Plate  Unit  for  An 
A.  C.  Lamp   Socket 


illustrated!  At  the  top  we  have  a  con- 
nection to  a  110  volt  alternating  current 
source,  and  at  the  bottom  the  output 
terminals  for  the  direct  current.  One 
terminal  of  the  A.  C.  runs  straight  over 
to  the  D.  C.  side,  while  the  other  lead  is 
interrupted  by  the  rectifier.  This  is  a 
tube  containing  a  filament  and  a  plate. 
The  filament  is  lighted  by  a  battery  and 
its  temperature  regulated  by  a  rheostat. 
Electrons  are  then  given  off  by  the  fila- 
ment as  soon  as  the  direct  current  posts 
are  closed  through  some  circuit  where  the 
voltage  is  to  be  used,  and  the  plate  is 
then  charged  positively.  The  dotted 
arrows  show  the  direction  of  electronic 
flow,  whereas  the  full  arrows  show  the 
assumed  direction  of  current  flow. 

Thus  the  vacuum  tube  points  out  that 
the   old    assumption    of   current    flowing 


Fig.  1.  The  simplest  rectifier,  using  a 
vacuum  tube.  Dotted  arrows  point  out 
electron  flow.  Full  arrows  show  current 
flow  as  assumed  before  the  advent  of  tubes. 


from  positive  to  negative  is  in  reality  in- 
correct, though  it  does  no  harm  to  con- 
sider that  the  current  of  electricity  does 
go  in  that  direction  so  long  as  we  under- 
stand which  way  the  electrons  actually 
proceed.  In  such  a  rectifier  circuit,  it  is 
easy  to  remember  in  case  of  doubt  that 
the  positive  lead  always  comes  from  the 
rectifier  filament  circuit  and  the  negative 
from  the  remaining  side  of  the  A.  C. 
supply  line. 

Now,  getting  our  rectifier  down  to 
workable  proportions,  we  at  once  run  up 
against  the  question  of  the  tube.  The 
UV  201A  or  the  C301A  tube  will  answer 
with  perfect  satisfaction,  even  though  it 
has  an  extra  element  which  doesn't 
seem  essential.  The  grid,  being  nearer 
to  the  filament,  does  more  of  the  rectify- 
ing than  the  plate,  so  that  the  grid  is  in 
truth  the  "plate"'  of  the  rectifier.  How- 
ever, to  slightly  increase  the  electronic 
stream  and  thus  make  it  possible  to 
obtain  more  voltage  on  the  D.  C.  side, 
both  grid  and  plate  are  connected  to- 
gether as  the  "plate"  of  the  rectifier 
tube. 

Transformers 
TT  IS  not-  convenient  to  illuminate  the 
-*-  rectifier  by  means  of  a  battery,  so  a 
simple  bell  ringing  transformer  is  adopted 
instead.  These  are  used  in  house  wiring 
for  supplying  power  to  doorbells  and 
buzzers  and  are  very  cheap  little  instru- 
ments (SI  to  S2)  and  have  a  6  or  8  volt 
output.  Now,  while  a  straight  connec- 
tion to  the. 110  volt  line  will  function,  it  is 
preferable  for  several  reasons  to  inter- 
pose a  transformer  between  the  rectifier 
unit  and  the  line.  In  the  first  place,  the 
A.  C.  "hum"  doesn't  get  through  quite 
so  easily  that  way,  and  then  it  is  impossi- 
ble to  short-circuit  the  line  and  blow 
fuses  through  errors  in  connections  when 
a  transformer  is  inserted. 

The  ordinary  audio  frequency  amplify- 
ing transformer  is  just  the  thing  for  the 
purpose.  It  must  be  a  good  strong  one, 
with  its  parts  securely  clamped  or  bolted 
together  at  several  points.  An  insecurely 
assembled  transformer  may  do  for  audio 


12         RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


,AFJ 


110  AC 


f^H^ 


BELL   TRANS. 


Fig.  2.     A  one  tube  "B"  voltage  rectifier,  suitable  for  sets  using  no  more  than  three  receiving    tubes. 


amplification,  but  with  110  volts  A.  C. 
on  its  primary,  the  laminations  of  the 
core  will  start  to  vibrate  with  a  60  cycle 
frequency.  Referring  to  Fig.  2,  we 
observe  that  the  primary  of  the  A.  F. 
transformer  is  connected  across  the  A.  C. 
line,  as  is  the  primary  of  the  bell  ringing 
transformer. 

The  secondary  of  the  bell  transformer 
is  connected  to  the  filament  posts  of 
the  tube  socket  through  a  rheostat  R-l 
of  about  15  ohms  resistance.  The  plate 
and  grid  posts  are  connected  together 
and  to  one  of  the  secondary  posts  of  the 
audio  transformer — it  makes  no  differ- 
ence which.  In  order  to  smooth  out  the 
remaining  irregularities  and  ripples  in 
the  rectified  current,  it  is  necessary 
to  provide  a  "filter"  circuit.  This  is 
composed  of  two  coils  of  wire  wound  on 
an  iron  core  and  two  large  fixed  con- 
densers. The  condensers  absorb  electri- 
cal energy  when  the  voltage  increases 
and  they  give  it  out  again  when  the 
voltage  drops,  thereby  having  the  effect 
of  steadying  the  voltage.  They  are 
merely  reservoirs  which  maintain  the 
voltage  constant.  The  "choke"  coils 
act  like  flywheels  on  a  gasoline  engine. 
Without  the  flywheel,  the  motion  of  the 
engine  would  naturally  be  uncontrollably 
jerky,  but  with  it  the  energy  is  stored  in 
the  heavy  wheel  and  "smoothed  out" 
through  its  inertia.  The  coils  oppose 
any  sudden  change  in  voltage  or  current 
strength.  Thus,  with"  condensers  to 
equalize  the  voltage  and  with  coils  to 
oppose   any  change   in   the   voltage,   the 


pulses  of  direct  current  released  via  the 
tube  are  "ironed  out"  into  a  continuous 
and  unruffled  uni-directional  current. 

The  choke  coils  are  conveniently 
suited  in  their  requirements  to  two 
windings  of  another  audio  frequency 
transformer,  this  being  any  non-descript 
make  of  transformer,  since  it  neither 
carries  a  heavy  current  nor  is  subject  to 
alternating  voltage.  The  output  binding 
posts,  "B"  plus  and  "B"  minus,  are 
connected  to  the  amplifier  terminals 
of  the  set.  For  the  detector,  unless  it's 
a  soft  tube,  a  variable  resistance  having 
a  resistance  variable  between  about 
10,000  and  75,000  ohms,  is  inserted  in 
series  with  the  detector  plus  "B"  post. 
This  resistance  is  shown  at  R-2.  Except 
with  the  ultra-audion  circuit,  it  is  neces- 
sary to  provide  a  by-pass  condenser  in 
the  plate  circuit  of  the  detector,  as  from 
"DET."     "B"  to  minus  "B." 

Limits   of   the   Rectifier 

\  S  shown  in  Fig.  2,  "B"  voltage  may 
-^*-  be  supplied  to  a  three  tube  set, 
detector  and  two  stages  of  audio  or  any 
other  combination  using  three  tubes  or 
less.  It  is  essential  that  the  rectifier 
tube  be  a  good  one,  new  if  possible,  for  an 
exhausted  tube — one  that  does  work 
passably  in  the  audio  socket — won't  do 
for  rectification.  The  detector  may  be 
supplied  with  voltage  from  the  unit, 
although  if  it  is  a  soft  tube  calling  for  an 
exact  plate  voltage  of  from  20  to  25 
volts,  it  is  pretty  hard  to  regulate  it  with 
sufficient    accuracv    with    the    resistance 


R-2.  In  such  cases  it  is  best  to  employ 
a  separate  22  1-2  volt  "B"  battery  for 
the  detector.  In  that  case,  a  four  tube 
set  might  be  used  with  the  unit,  supplying 
actual  voltage  to  only  three  tubes,  how- 
ever. 

One  very  fine  feature  of  the  rectifier 
is  its  fool-proof  quality.  You  may 
short-circuit  the  D.  C.  posts  as  often  and 
as  long  as  you  please  without  harming  a 
thing.  You  may  even  place  the  filaments 
of  your  most  precious  tube  across  the 
"B"  posts  without  burning  it  out!  This 
safety  feature  is  due  to  the  sudden  drop 
to  zero  in  the  output  voltage  when  more 
than  about  15  milliamperes  of  current 
are  called  for.  The  old  story  of  tubes 
going  "west"  from  an  erroneous  applica- 
tion of  "B"  voltage  can't  be  repeated. 

A  few  words  as  to  the  condensers  C-l 
and  C-2.  In  case  the  loud  speaker  only 
is  to  be  used,  these  may  be  two  micro- 
farads each  without  noticeable  hum  from 
the  A.  C.  line.  However,  for  headphone 
use  it  is  better  to  increase  these  to  four 
mfds.  each  by  using  two  2  mfds.  condens- 
ers in  parallel  on  either  side  of  the  choke 
coils.  Suitable  condensers  are  made  by 
many  electrical  firms  for  telephone 
purposes,  and  are  merely  long  strips  of 
tin-foil  separated  by  thin  waxed  paper, 
sealed  tightly  within  tin  containers. 
They  should  be  of  good  quality,  or  inter- 
nal vibration  due  to  loose  sheets  and 
leakage  through  inferior  insulation  may 
detract  from  the  good  operation  of  the 
unit. 

(Turn  to  page  61) 


0  8- 


DET 3+ 


AMP  B^ 


3£LL  TRAN5. 


Fig.  3.      For  larger  sets  using  up  to  five  tubes,  the  rectifier  is  made 
heavier  by  using  two  tubes  whereby  both  "sides"  of  the  A.C.  are  rectified. 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour        13 


€[  A  Hookup  for  Those  who  "Roll  Their  Own" 


A  Set 

for  True 
Tone  Quality 


^BOVE  is  a  view  of  the  3-circuit  tuner 
partially  wired.      The  resistance  cou- 
'ed  amplifier  at  the  left  will  give  maximum 
<lume  with  the  least  distortion. 


Quiet 
DXaBig 

Advantage 


Adding  a  Good  Amplifier  to 
the  3-Circuit  Tuner 


OUT  of  the  hundreds  of  home-made 
receiving  sets  a  large  number  are 
designed  with  some  type  of  three 
circuit  tuner.  This  hookup  has  proven 
of  great  value  to  every  radio  fan  who 
"rolls  his  own,"  and  without  a  doubt  it 
is  the  most  sensitive  and  selective  type  of 
circuit  so  far  known.  One  might  call  it 
a  "poor  man's  radio,"  because  it  is  so 
very  easy  to  construct  and  so  simple  to 
operate,  to  say  nothing  of  the  small  cost 
of  parts.  As  a  general  rule,  the  present 
day  radio  fan  is  not  content  with  earphone 
reception  and  he  most  always  plans  his 
receiving  set  with  loud  speaker  operation 
in  view. 

Although  very  little  has  been  done  to 
add  radio  frequency  amplification  to  the 
three  circuit  tuner,  at  least  two  stages 
of  audio  amplification  are  generally  in- 
cluded in  the  outfit.  Low  loss  parts  such 
as  coils  and  condensers  play  an  important 
part  in  the  makeup  of  an  efficient  receiver. 
A  well  designed  layout  of  the  parts  should 
also  be  kept  in  mind  with  special  effort 
put  upon  the  tuning  parts  of  the  circuit, 
which  should  be  wired  with  care. 

Perfect  Tone  Desired 

TN  an  effort  to  improve  upon  the  ordi- 
■*-  nary  three  circuit  tuner  with  its  usual 
two  stages  of  transformer  coupled  amplifi- 
cation, the  writer  set  out  to  design  a 
receiving  set  which  would  give  as  near  to 
perfect  reproduction  of  voice  and  music 
as  possible.  Having  an  ear  for  musical 
tones,  audio  amplifications  with  trans- 
formers did  not  always  satisfy  the 
writer. 


By  ALBERT  E.  SONN 

Having  in  mind  the  standard  form  of 
resistance  coupled  amplification,  which 
is  recognized  as  the  most  successful 
system  of  amplifying  for  quality  repro- 
duction, the  standard  three  circuit  set 
was  put  together  so  as  to  include  this 
form  of  amplification.  This  takes  the 
place  of  the  ordinary  transformer-coupled 
job,  thereby  doing  away  with  the  choice 
of  transformers.  "Turn-ratios"  or  "am- 
plification constants,"  "C"  batteries  and 
so  forth  were  all  forgotten  for  the  time 
being,  as  the  resistance  coupled  amplifier 
is  far  simpler  to  install  and  operate. 
Other  advantages  are,  that  it  saves  upon 
B  battery,  consuming  a  great  deal  less 
current  than  the  ordinary  two  step 
amplifier  with  transformers.  Actual 
measurements  have  proven  this  to  the 
writer. 

The    circuit,  constructed    was    put    to 


'T^HE  3-circuit  tuner  is  one  of  the 
■*  most  popular  sets  among  the  home 
builders. 

It  is  easy  to  construct  and  fur- 
nishes clear  music.  Particularly  is 
it  efficient  for  the  fan  who  wants  loud 
speaker  operation  without  going  to  great 
expense  in  buying  parts.  This  article 
by  Mr.  Sonn,  a  well  known  Eastern 
radio  engineer,  tells  how  to  make  this 
4-tube  set  so  that  it  will  give  a  true 
reproduction  of  broadcast  reception. 


several  tests,  not  only  by  the  builder 
himself,  but  a  number  of  others  who  tried 
it  for  their  own  satisfaction.  Everyone 
gave  a  very  favorable  report  upon  its 
remarkable  operation.  Believing  that 
the  circuit  is  well  worth  consideration,  the 
writer  is  passing  along  the  information 
to  his  fellow  readers. 

Selection  of  Parts 

1\ /TUCH  printers'  ink  has  been  used  in 
-"-'J-  instructing  radio  fans  how  to  select 
good  parts  in  which  the  electrical  losses 
are  very  low.  It  is  felt  that  every  radio 
fan  has  been  warned  against  cheap  and 
inferior  parts.  There  are  a  few  really 
good  variable  condensers  on  the  market. 
There  are  a  lot  called  "low  loss  type," 
which  are  of  poor  construction,  although 
their  makers  claim  all  sorts  of  things  for 
them.  Select  a  good  condenser  of  .0005 
mfds.  capacity  (approx.  23  plates).  This 
condenser  tunes  the  secondary  coil  of  the 
vario-coupler.  With  a  good  condenser 
and  a  poor  coupler  we  do  not  gain  much. 
Choose  a  good  condenser  to  match  a  low 
loss  coupler.  The  type  shown  in  the 
photograph  was  picked  out  by  the 
writer  as  it  has  proven  in  other  sets  to  be 
of  the  ideal  type.  It  tunes  sharp  in  this 
circuit  and  has  ability  to  pick  up  and 
hold  a  great  many  stations  not  heard  at 
all  in  other  couplers. 

It  has  an  adjustable  primary,  which  is 
very  important.  This  consists  of  about 
8  turns  of  No.  16  DCC  wire  wound  on  a 
three  inch  tube.  The  secondary  is 
wound  in  basket  weave  style  and  con- 
tains about  45  turns  of  wire.     The  plated 


14 


RADIO   AGE/or  April,  1925 


coil  contains  18  turns  of  No.  18  wire 
wound  on  a  tube  similar  to  the  primary. 
The  secondary  is  about  3f£  inches  in 
diameter.  The  three  coils  are  mounted 
on  a  special  aluminum  stand  for  panel 
mounting. 

The  antenna  and  ground  are  connected 
to  the  ends  of  the  aerial  coil  of  8  turns. 
Flexible  leads  are  provided  for  this 
purpose. 

The  secondary  is  connected  across  the 
.0005  variable  condenser  and  the  ends 
go  to  the  "grid"  and  "Fil."  connections 
in  the  circuit.  The  tickler  winding  is 
in  the  plate  circuit,  one  side  going  to  the 
plate  terminal  of  the  detector  tube  and 
the  other  to  the  input  posts  of  the  resist- 
ance coupled  amplifier  circuit.  Care 
should  be  taken  to  follow  the  drawing 
closely.  The  input  circuit  also  connects 
to  the  positive  B  battery  at  about  45 
volts. 

The  Ainput"  is  also  shunted  with  a  .002 
micadon  fixed  condenser.  The  latter 
condenser  is  important,  as  the  set  will 
not  work  without  it. 

Amplifier  Unit  Employed 

TTAVING  been  through  the  "mill" 
■*-■*-  with  various  forms  of  resistance 
coupled  amplifiers  using  either  variable 
or  fixed  resistances,  experience  taught  the 
writer  to  be  extremely  careful  in  the 
selection  of  a  unit  to  go  with  this  regener- 
ative receiver.  Accuracy  of  leak  resist- 
ances and  permanency  are  very  important. 
Fixed  condensers  of  the  right  value  also 
play  an  important  part  in  this  circuit. 
Leaks  which  change  in  resistance  value 
every  time  the  weather  changes  are  to 
be  avoided.  The  latter  are  usually 
found  in  cheap  forms  of  grid  leak  resist- 
ances. It  is  difficult  for  the  set  builder 
to  tell  if  he  has  an  inaccurate  resistance 
in  the  circuit.  He  must  take  the  maker's 
word  for  the  resistance  value,  although 
it  may  have  changed  several  points  in  a 
week's  time. 

The  unit  selected  was  just  the  right 
size  to  fit  on  the  base  board,  and  as  it  has 


all  of  the  resistance  units  and  condensers 
already  in  circuit,  the  chance  of  going 
wrong  in  its  use  was  hardly  possible. 
The  sockets  and  mounts  for  the  leaks  and 
condensers  were  all  mounted  in  a  block 
of  bakelite  with  binding  posts  arranged 
on  the  side  for  all  connections.  This 
saved  a  good  deal  of  space  that  otherwise 
would  be  occupied  by  sockets,  mountings 
and  condensers. 

The  "input"  terminals  were  also 
located  in  a  convenient  place  so  that  the 
detector  tube  circuit  could  be  coupled 
up  with  very  short  leads.  As  can  be  seen 
from  the  drawing,  one  of  the  "input" 
wires  connects  to  the  detector  B  battery, 
while  the  other  connects  to  the  plate  wire 
from  the  tickler  coil.  The  bakelite  base 
contains  all  the  necessary  connections 
for  "A"  and  "B"  battery. 

A  small  fixed  resistance  was  connected 
to  the  negative  side  of  the  filament  circuit 
from  the  storage  battery.  This  did  away 
with  an  extra  resistance  on  the  panel. 
The  amplifier  tubes  do  not  require  a 
critical  adjustment  and  a  fixed  resistance 
will  do  at  this  point.  A  20  ohm  rheostat 
was  provided  on  the  panel  to  control  the 
detector  voltage. 

The  convenient  form  in  which  the 
resistance  coupled  amplifier  is  laid  out, 
makes  it  unnecessary  to  wire  up  this  part 
of  the  circuit.  Following  specified  instruc- 
tions, a  .002  fixed  condenser  was  placed 
across  the  "input"  terminals. 

A  "B"  battery  of  90  volts  will  work  this 
amplifier,  although  135  volts  or  three  4-5 
volt  "B"  battery  blocks  are  required  for 
better  volume.  It  is  suggested  that  90 
volts  be  tried  out  first,  and  if  the  volume 
is  not  enough,  it  is  very  easy  to  add 
another  battery.  The  tubes  required  are 
of  the  201-A  or  C  301-A  type.  Attempts 
to  use  dry  cell  types  of  tubes  only  prove 
fruitless.  It  is  well  to  "swop"  tubes 
around  in  their  sockets  until  a  good 
combination  is  found.  Some  tubes  work 
better   than   others   for  amplifiers. 

The  detector  should  also  be  of  the 
201-A  type. 


The  Magazine  of  the  Hour 

T^HIS  four  tube  receiver  will  certainly 
■*-  satisfy  the  DX  hound,  as  it  will  pull 
pretty  nearly  everything  in  the  "air." 
It  will  bring  in  these  stations  with  a  clear 
cut  tone.  There  is  no  distortion  unless 
the  transmitter  is  distorting. 

Excellent  on  DX 

A  log  run  on  this  set  for  a  period  of  two 
weeks  showed  that  it  "brought  home  the 
bacon"  on  the  DX  list.  One  of  the 
remarkable  things  about  it  was  that  it 
did  not  appear  noisy  on  DX. 

In  fact,  it  was  the  smoothest  operating 
outfit  the  writer  has  tried  within  the 
past  year  or  two.  A  glance  at  the  photo- 
graph also  impresses  one  with  the  extreme 
simplicity  of  the  wiring. 

Check  up  on  the  wiring  carefully  and 
see  that  all  connections  are  tight.  A 
loose  connection  destroys  the  usefulness 
of  many  sets.  It  is  a  good  plan  to  go 
over  each  piece  of  apparatus  before 
mounting  it  on  the  baseboard  or  sub- 
panel  and  tighten  every  bolt  or  nut  that 
is  used  for  connecting  purposes. 

Tube  sockets  and  rheostats  must  be 
gone  over  in  this  manner,  especially 
before  they  are  mounted.  Connections 
on  these  are  rather  inaccessible,  once 
they  are  fastened  to  the  sub-panel  or 
baseboard. 

Fixed  condensers  should  be  tested 
before  they  are  fastened  in  place  per- 
manently. Do  not  solder  directly  to  a 
fixed  condenser,  as  this  will  often  cause 
the  tin-foil  to  fuse  and  run  together, 
thus  making  the  condenser  useless. 
Use  a  soldering  lug  to  solder  the  wire 
on  the  smaller  end,  and  with  the  aid  of  a 
small  nut  and  bolt  fasten  the  other  end 
to  the  fixed  condenser. 

Mistakes  are  often  made  in  connecting 
the  three  circuit  tuner,  preventing  it  from 
giving  maximum  results.  For  example, 
connecting  wires  from  the  secondary  and 
tickler  are  often  reversed  in  such  a  way 
that  the  coils  are  working  in  opposition 
to  one  another. 

You  can  rely  on  this  circuit. 


Above  is  the  wiring  diagram  for  the  three  circuit  tuner  with  three  stages  of  resistance  coupled  amplification.     This  method  of 
amplifying  gives  wonderful,  clear  tone  to  the  incoming  signals. 


RADIO   AGE  for  April,  1925  The  Magazine  of  the  Hour  15 

The  Secret  of  Successful  Reception 

Lies  in 

WIRING  your 
Set  PROPERLY 


By  C.  HAROLD  DILLON 


4F1ER  you  have  purcnased  the 
uk  various  parts  that  go  to  make 
—  ■*-  up  a  radio  set  and  have  had  the 
panel  drilled  and  engraved,  the  problem 
of  wiring  the  different  pieces  of  apparatus 
presents  itself.  To  most  of  us  this  is 
disregarded  to  a  great  extent.  By  that 
I  mean  that  the  few  fundamental  laws 
governing  such  things  are  not  strictly 
adhered  to.  This  is  one  of  the  reasons 
why  so  many  set-builders  have  so  little 
success  with  some  of  the  receiving  cir- 
cuits  that    they   have   constructed. 

Practically  all  technical  articles  ad- 
vise the  builder  to  make  his  connections 
in  a  direct  manner;  that  is,  from  one 
terminal  to  the  other.  Upon  reading 
this  advice  we  have  visions  of  wires 
connected  from  place  to  place,  making 
the  inside  of  the  set  resemble  a  screen. 
Comparing  that  vision  with  many  of 
the  high  grade  manufactured  sets  that 
we  have  seen,  whose  wires  are  spaced 
evenly  and  all  seem  to  have  a  definite 
point  at  which  to  terminate,  we  do 
not  take  much  stock  in  the  aforemen- 
tioned advice,  "Make  connections  di- 
rect;" and  the  result  is  that  the  finished 
set  has  a  wonderful  appearance,  but 
somehow  it  just  won't  do  what  it  is 
supoosed   to. 

How  Not  to  Proceed 

/~\N  THE  other  hand,  some  of  us 
^■'  who  are  not  very  handy  with  the 
soldering  iron  or  the  pliers  too,  for 
that  matter,  have  a  sneaking  suspicion 
that  so  much  care  is  just  "space  filler," 
and  proceeding  to  the  hardware  store 
they  purchase  a  roll  of  anunciator  wire, 
which  is  draped  around  the  instruments 
in  the  most  convenient   manner. 

Both  these  systems  are  wrong,  and 
a  little  bit  of  thought  on  the  part  of  the 
builder  will  enable  him  to  realize  just 
what  to  do  to  avoid  complications  of 
this   nature. 

In  the  first  place,  when  you  are  ad- 
vised to  make  connections  direct,  it 
does  not  mean  that  you  must  sacrifice 
appearance.       Certain     wires     must     be 


Above  is  a  bottom  view  of  a  seven-tube  super-heterodyne  receiver  wired  according  to 
the  most  approved  manner.  Notice  the  direct  manner  in  which  all  the  connections  are 
made.  Soft  No.  14  wire  was  used  throughout.  At  the  upper  left  is  a  photograph  show- 
ing the  new  "cable"  method  of  hooking  up  the  set. 


connected  as  directly  as  possible,  while 
others  can  be  placed  in  the  most  con- 
venient or  practical  place.  For  ex- 
ample, grid  and  plate  connections  should 
be  placed  as  far  from  one  another  as 
possible,  at  the  same  time  remembering 
to  keep  them  as  short  as  you  can. 

The  filament  wires,  as  a  general  rule, 
can  be  placed  as  -convenient.  The 
positive  "B"  connections  should  be 
kept  free  from  any  of  the  other  wires, 
as  this  lead  carries  a  great  deal  of  the 
high  frequency  current,  and  for  that 
reason  complications  of  a  most  dis- 
tressing nature  will  arise  if  it  is  placed 
in  close  proximity  to  other  wires  in  the 
circuit. 

In  the  foregoing  paragraphs  I  have 
assumed  that  the  builder  is  using  the 
ordinary  stiff,  bus-bar  wire.  Many 
fans  are  under  the  impression  that  it  is 
absolutely  necessary  to  use  wire  of  this 
kind.  This  is  not  the  case,  however. 
Any  wire  that  is  of  sufficient  size  to 
prevent  of  high  resistance  losses  being 
placed  in  the  circuit  will  suffice,  and 
needless  to  say,  it  does  not  have  to  be 
stiff.  In  fact,  better  and  more  direct 
connections  can  be  made  with  softer  or 
more  flexible  wire.  There  has  been 
placed  on  the  market  quite  recently 
a  special  Number  Fourteen,  cambric- 
covered,  soft  wire  that  adapts  itself  to 
radio  set  wiring  very  well.  Using  wire 
of  this  type,  the  set-builder  will  save 
himself  considerable  time  in  making 
connections. 


COMING  back  to  the  question  of 
appearance,  most  fans  will  still 
insist  that  the  commercial  set  will 
present  a  far  neater  appearance  than 
the  home-made  one.  This  might  be 
true  to  a  certain  extent,  but  have  you 
really  noticed  how  this  illusion  is  accom- 
plished? The  next  time  you  have  the 
opportunity  of  looking  at  a  manu- 
factured set,  notice  how  the  sub-panel 
or  base  is  placed.  Practically  all  the 
wiring  is  done  on  the  under  side,  and 
what  few  wires  we  see  on  the  upper 
side  are  probably  those  to  which  I  have 
referred  in  a  preceding  paragraph  as 
not  being  necessary  to  install,  in  accord- 
ance with  the  theory  of  short  connec- 
tions; namely,  the  filament  circuit  wires. 
This  practice  is  becoming  a  general 
one  and  also  a  very  good  one,  as  it  does 
make  the  set  look  neater,  excludes 
dust  and  dirt  to  a  large  extent,  and 
last  but  not  least,  permits  of  extremely 
short    connections. 

For  R.  F.  Wiring 

The  above  advice  holds  good  on  any 
circuit  and  particularly  on  circuits  of 
the  regenerative  type.  In  wiring  cir- 
cuits of  the  radio  frequency  kind  it  is 
possible  to  use  another  method  that 
greatly  facilitates  rapid  and  efficient 
wiring.  This  method  is  quite  new,  and 
a  large  number  of  commercial  companies 
are  rapidly  discarding  the  old  bus-bar 
method  for  it.  It  is  referred  to  as  the 
"cable   method"   and  just   as  the   name 


16         RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


implies,  a  small  cable  is  used  in  place  of 
the  usual  bus. 

When  wiring  a  set  by  this  method, 
the  advice  concerning  the  grid  and 
plate  wires  is  adhered  to,  but  the  other 
wires  are  formed  into  a  cable  with  the 
aid  of  some  waxed  string  and  a  few 
nails.  The  photograph  shows  this 
method  of  wiring  quite  clearly,  and  its 
advantage  is  of  course  simplicity.  To 
connect  the  various  instruments  in 
this  manner,  first  decide  the  most  con- 
venient place  in  which  to  locate  the 
cable,  bring  all  wires  to  this  point  and 
wrap  them  together  with  the  waxed 
string.  The  nail  is  used  to  make  bends 
in  the  wire.  If  a  sub-panel  is  not  used, 
but  a  wooden  baseboard  is  employed, 
then  the  nails  can  be  driven  into  it, 
(the  baseboard)  a  short  distance,  and 
the  wires  brought  around  them  to  be 
held  in  place  till  you  are  ready  to 
bind  them  together  with  the  waxed 
string. 

It  is  best  to  use  the  waxed  string 
in  an  endless  fashion,  using  a  series  of 
half  hitches  about  an  inch  apart  to 
bind  the  wire.  The  illustration  in 
another  part  of  this  article  shows  you 
how  to  bind  the  wires  together. 

As  before  stated,  this  method  of 
wiring  can  be  used  to  best  advantage 
in  circuits  that  are  strictly  radio  fre- 
quency ones.  It  would  be  impossible 
to  use  it  with  any  degree  of  success  in 
reflex    or    regenerative,   circuits. 

Some  of  us  are  a  little  skeptical  about 
using  soldering  lugs  in  making  con- 
nections to  binding  posts.  We  simply 
bend  the  wire  around  the  bolt,  screw 
down  the  nut  and  let  it  go  at  that. 
In  about  seventy-five  per  cent  of  the 
sets  that  I  have  been  called  to  service 
in  the  past  year,  poor  results  could  be 
traced  to  this  fault.  It  is  bad  practice 
to  even  use  the  binding  posts  at  all. 
Connections  should  be  soldered  directly 


The  drawing  of  the  wire  with  the  looped 
end  at  the  left  of  the  picture  shows  the 
proper  method  of  making  connections  to 
binding  posts.  The  one  on  the  right  hand 
side  is  incorrect.  A  little  extra  time  on 
these  things  and  you  build  a  better  set. 

to  them,  but  many  of  the  set  builders 
do  not  like  to  do  this,  especially  those 
who  have  never  learned  to  solder  prop- 
erly. For  occasionally  a  drop  of  solder 
will  fall  on  a  coil  or  work  its  way  between 
the  plates  of  a  condenser,  causing  no 
end  of  trouble. 


The  above  cut  shows  the  proper  method 
of  soldering  two  wires  together.  This  method 
is  more  efficient  than  the  ordinary  method  of 
making  "butt"  joints. 

THERE  have  been  recently  placed 
on  the  market  several  special  kinds 
of  pliers  and  attachments  for  the  ordin- 
ary plier  that  will  enable  one  to  bend 
the  end  of  the  wire  in  a  perfect  loop. 
One  of  these  implements  should  be 
acquired  by  the  experimenter  who  does 
not  like  to  solder.  He  will  find  him- 
self repaid  a  thousand  times  for  the 
small  amount  he  will  have  to  invest  for 
this   useful   article. 

Great  care  must  be  exercised  in 
making  sure  that  the  binding  posts 
nuts  are  fastened  tight,  whether  a 
soldering  lug  or  the  bent  end  of  wire  is 
used.  When  bending  wire,  do  not  be 
satisfied  with  merely  bending  a  small 
hook  on  the  end  to  be  placed  under  the 
binding  post.  Make  the  hook  a  full, 
round  shape  and  fasten  it  securely. 
Then  you  will  be  sure  of  good  results. 
Sets  that  are  not  soldered  together  should 
be  gone  over  at  frequent  intervals  and 
all  nuts  and  bolts  tightened  up.  This 
may  seem  like  foolish  advice,  but  if  your 
set  is  one  of  the  kind  that  is  not  soldered, 
try  it  and  see.     You'll  be  surprised. 

Another  thing  that  sometimes  causes 
untold  trouble  is  the  soldering  of  fixed 
condensers  in  a  circuit.  Occasionally 
the  builder  will  hold  the  hot  soldering 
iron  on  the  fixed  condenser  for  too 
long  a  time,  and  the  result  is  that  the 
lead-foil  of  which  the  condenser  is  made 
will  fuse  and  melt,  short  circuiting  the 
condenser,  whose  value  in  the  circuit 
will  be  absolutely  nil.  For  this  reason 
it  is  advisable  to  use  a  short  bolt  and 
nut  for  fastening  these  condensers  in 
place.  However,  if  one  uses  a  little 
care,  soldering  them  in  place  is  much 
more    effective. 

If  the  joints  to  be  soldered  are  clean 
and  a  good  flux  (non-corrosive)  is  used, 
it  will  only  take  a  touch  of  the  iron  to 
complete  the  joint.  Most  experimenters 
it  seems,  do  not  keep  the  iron  hot 
enough.  Keeping  it  hot  is  the  real 
secret    of    successful    soldering. 

Another  thing  that  often  will  cause 
trouble  in  the  soldered  connections  is 
butt  end  joints.  It  is  far  better  to 
wind  the  wire  around  the  one  that  you 
are  going  to  solder  onto,  rather  than  to 
simply  bend  one  end  "L"  shape  and 
connect  with  solder. 


While  discussing  solder,  it  might  be 
well  to  warn  the  builder  against  some 
of  the  pastes  and  soldering  compounds 
on  the  market.  They  are  all  right  for 
the  tin-smith  or  sheet  metal  worker, 
but  are  absolutely  useless  for  the  radio 
constructor.  There  are  several  pastes 
manufactured  especially  for  radio  work, 
and  guaranteed  by  the  manufacturer 
which  will  not  corrode.  Consult  the 
advertising  columns  of  the  radio  mag- 
azines and  select  one. 

Use    a    Metal    as    Protector 

GARE  should  be  taken  to  see  that 
a  small,  thin  piece  of  metal  is 
placed  in  such  a  manner  under  the 
joint  to  be  soldered  that  none  of  the 
excess  solder  will  run  to  places  where 
it  should  not  be.  This  is  especially 
true  when  soldering  to  coils  of  wire  that 
have  silk  insulation.  Many  coils  are 
practically  ruined  in  this  manner.  Care 
should  also  be  taken  to  be  sure  that 
none  of  the  solder  leaks  through  joints 
made  on  variable  condensers.  This 
may  strike  you  as  being  rather  odd, 
but  it  happens  a  great  many  times 
with  disastrous  results.  On  one  occasion 
it  caused  a  short  circuit  that  ruined 
eight  tubes  before  the  fault  was  de- 
tected. A  final  caution  regarding  solder- 
ing is  to  keep  the  iron  well  tinned. 
A  sharp  file  and  a  piece  of  salimoniac 
will  enable  you   to  do  this. 

Never  use  wire  smaller  than  Number 
Twelve.  In  fact,  it  is  well  to  standardize 
on  Number  Fourteen,  for  in  this  manner 
you  will  eliminate  all  difficulties  from 
high    resistance    in    the    circuit. 

Never  use  wire  that  is  stranded.  By 
that  is  meant  the  kind  that  is  usually 
referred  to  as  "Litz"  wire.  There  was  a 
time  when  it  was  thought  that  this 
would  prove  to  be  the  ideal  kind  of  wire 
for  radio  purposes,  but  experiments 
have    proved    that     this    wire    is    of  no 


The  above  illustration  shows  the  method 
of  binding  the  wires  in  the  cable  together. 

practical  use.  As  you  know,  this  wire 
is  composed  of  several  strands  of  very 
fine  wire  which  is  easily  cracked  and 
broken.  When  it  reaches  this  state,  the 
old  "jinx,"  high  resistance,  is  with  us 
once  more  and  our  results  are  anything 
but  the  best.  From  the  foregoing  it  is 
obvious  that  substantial  wire  having 
the  largest  surface  possible  is  the  ideal. 


RADIO   AGE  for  April,  1925 


The  Magazine  of  the  Hour         17 


Regulating  FILAMENT  Energy 


All  Sets 

Function  Best 

When  the  Tube 

Emission  is 

Constant 


WITH  the  increasing  use  of  mul- 
tiple tube  sets,  the  radio  fan's 
troubles  are  likely  to  increase 
unless  strict  control  is  had  of  all  the 
various  factors  in  the  circuit.  This 
is  especially  true  of  circuits  in  which 
local  oscillating  energy  is  used,  such 
as  in  the  super-heterodynes. 

It   goes   without    saying    that    any 
set  using  vacuum  tubes  will  work  bet- 
ter if  the  filaments  are  kept  at  a  fairly 
constant    temperature     so     that     the 
emission    will    remain    constant,    and 
this  readily  is  done  if  a  simple  voltmet- 
er is  connected  across  the  filament  termi- 
nals  of   the    tubes.     With    the    modern 
tendency  to  group  several  tubes  on  one 
rheostat,  this  means  that  one  voltmeter 
will  take  care  of  each  group  of  tubes. 

Moreover,  if  several  groups  are  used, 
there  can  be  had  voltmeters  equipped 
with  switching  arrangements  so  that  the 
voltage  across  any  one  of  several  groups 
of  tubes  may  be  read.  Such  an  instru- 
ment arranged  for  three  separate  groups 
is  shown  with  the  filament  wiring  to  three 
single  tubes. 

The  most  common  grouping,  of  course, 
consists  of  placing  all  of  the  intermediate 
frequency  amplifiers  on  one  rheostat  and 
the  rest  of  the  tubes  on  the  other.  If  a 
further  split  is  desired,  the  oscillator  is 
usually  handled  by  a  serrate  rheostat 
and  perhaps  the  first  detector. 

Rheostat  Conserves  Energy 

'  I  ''HE  great  advantage  of  controlling  the 
-*-  intermediate  frequency  amplifying 
tubes  lies  in  the  fact  that  by  lowering 
their  filament  voltage  the  volume  of  the 
set  may  be  regulated  in  a  somewhat 
similar  fashion  to  that  obtained  by  the 
use  of  a  potentiometer,  changing  their 
grid  bias,  but  with  the  result  that  the 
rheostat  tends  to  conserve  energy,  whereas 
the  potentiometer  scheme  tends  to  waste 
it  by  increasing  the  "B"  battery  current. 

Thus,  with  the  use  of  voltage  control 
across  the  filaments,  the  detectors  and 
audio  frequency  tubes  can  be  worked  at 
normal  brilliancy,  the  intermediate  fre- 
quency tubes  can  be  run  below  normal  for 
relatively  loud  signals,  as  indicated  by  the 
filament  voltmeter,  and  if  a  rheostat  con- 
trol is  placed  on  the  filament  of  the  oscilla- 
tor, it  will  be  found  very  useful  in  reducing 
the  amount  of  oscillatingenergy  produced, 
allowing  weak  signals  to  come  through 
with  much  better  volume  and  claritv. 


The  above  picture  shows  a  voltmeter 
arranged  to  enable  one  .to  read  the  filament 
voltage  on  three  separate  groups  of  tubes. 
This  is  accomplished  by  means  of  the  small 
switch  located  at  the  bottom  of  the  meter. 

By  JOHN  MILLER 


The  above  considerations  are  purely 
with  regard  to  the  operation  of  the  set. 
The  thoriated  filaments  in  common  use 
today  are  sensitive  to  overloading,  and 
operating  for  only  a  short  time  at  an 
abnormal  filament  voltage,  will  reduce 
the  efficiency  of  the  tube  very  noticeably. 

Tubes  rated  at  five  volts  should  be 
operated  with  at  least  no  excess  voltage. 
Usually  they  may  be  run  at  4.8  volts  and 
no  difference  in  volume  can  be  noticed, 
although  their  life  is  materially  length- 
ened. Operating  at  lower  voltage  will 
usually  reduce  the  signal,  so  we  may  say 
a  tube  should  be  operated  on  from  95%  to 
100%  of  its  rated  filament  voltage.  This 
applies  to  the  lower  voltage  type  as  well. 

How  Thoria  Boils  Off 
13  UT  if  the  filament  is  overheated  by 
-*-j'   applying   an   overvoltage  of  even  a 
few  per  cent,  the  thoria  in  the  filament, 


Picture  of  a  voltmeter  that  will  enable  the 
set  owner  to  keep  an  accurate  check  on  the 
voltage  of  both  the  filament  and  plate 
batteries. 


Voltage 

Control  in  the 

Super  Helps  to 

Prolong  Life 

of  Tubes 

which  is  the  activating  agent,  is  "boiled 
off"  at  an  abnormal  rate  and  when  it  is 
gone  the  tube  is  very,  very  dead. 
There  is  sufficient  thoria  in  the  fila- 
ment for  hundredsof  hoursof  operation 
at  normal  temperature,  but  even  a 
slight  increase  in  filament  temperature 
rapidly  ages  the  filament;  it  lives  fast 
and  furiously  and  dies  young. 

So  in  the  interest  of  economy,  if 
nothing  else,  we  should  run  our  tube 
filaments  at  the  proper  potential. 

In  connection  with  the  control  of 
the  intermediate  frequency  tubes 
mentioned  above,  it  is  an  excellent  idea 
to  place  a  milliammeter,  say  of  SO  milli- 
amperes  full  scale  value,  in  the  negative 
"B"  battery  lead  to  measure  total  "B" 
battery  current.  The  instrument  should 
be  placed  in  this  negative  lead  so  as  to 
measure  the  total  current,  and  it  will  be 
found  that  very  marked  variations  in 
this  current  will  be  had  with  variations 
in  filament  voltage  or  with  intermediate 
frequency  control  of  either  the  potentio- 
meter or  the  rheostat  type. 

A  high  resistance  rheostat  of  10,000  or 
15,000  ohms  may  be  placed  in  the  "B" 
battery  lead  to  the  intermediate  frequency 
amplifiers  for  controlling  the  stability  of 
the  circuit,  and  while  it  does  not  seem  to 
be  satisfactory  in  some  circuits,  in  others 
it  works  fully  as  well  as  any  other  means 
of  control.  The  usual  potentiometer 
method  of  stabilizing  the  tubes  simply 
consists  of  making  the  grids  of  the  inter- 
mediate amplifiers  more  positive,  which 
increases  the  plate  current  drawn  from 
the  "B"  battery.  This  increased  current 
causes  increased  losses  in  the  tubes  as 
well  as  in  the  associated  transformers, 
damping  out  the  oscillations. 

But  instead  of  increasing  the  current 
draw  at  a  fixed  voltage  to  keep  the  tubes 
from  oscillating,  we  can  lower  the  effec- 
tive voltage  across  the  tubes  by  a  variable 
series  resistance.  As  stated  above,  some- 
times it  works  and  sometimes  it  is  difficult 
to  find  the  proper  type  of  variable  resist- 
ance for  best  results.  The  scheme  is 
decidedly  worth  while,  however,  and  the 
milliammeter  in  the  negative  "B"  battery 
lead  will  show  a  materially  reduced  cur- 
rent draw,  perhaps  a  saving  of  50  per 
cent.  With  "B"  battery  energy  costing 
around  $30.00  a  kilowatt  hour,  we  might 
as  well  reduce  the  battery  and  pocketbook 
drain  by  efficiency  methods. 

With   better    methods   of   control,    we 
(Turn  to  page  54) 


18  RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


C.A  Word  to  Wise  Radio  Fans 


Tried  and  True 
Radio  Axioms 


By  ROSCOE  BUNDY 


After  answering  more 
than  4,000  letters  from 
radio  fans,  the  author  of 
this  article  compiled  these 
Radio  Axioms.   Save  them. 


ALL  radio  circuits  have  their  advan- 
tages and  limitations.  There  is  no 
single  circuit  which  embodies  per- 
fection in  distance,  selectivity,  signal 
strength  or  clarity  of  tone.  The  best  all 
around  circuit  is  one  in  which  intelligent 
compromises  have  been  made  between 
the  conflicting  factors  that  go  to  make  up 
radio.  If  we  desire  distance  reception 
above  all  else,  then  we  must  be  prepared 
to  stand  for  squeals  and  other  noises.  If 
we  desire  clarity  of  tone  and  selectivity, 
then  we  must  sacrifice  our  DX  ambitions. 
It  is  written  in  "THE  BOOK." 

After  trying  out  over  1,200  hookups  in 
my  own  laboratory  and  reading  the  re- 
sults of  other  experiments  until  the  total 
of  letters  answered  ran  well  over  4,000,  I 
have  come  to  the  conclusions  which  led 
to  the  following  table  of  "Radio  Axioms." 
If  you  experiment  long  enough  and  study 
long  enough,  you  will  appreciate  the  truth 
of   these   statements. 

1.  Selectivity  is  attained  at  the  expense 
of  signal  strength. 

2.  Conversely,  signal  strength  is  at- 
tained at  the  expense  of  selectivity. 

3.  No  detector  tube  is  a  good  audio 
amplifier. 

4.  No  good  amplifier  tube  is  an  ideal 
detector. 

5.  The  hookup  is  almost  a  negligible 
factor  when  compared  with  the  materials 
used,  the  workmanship  and  the  location 
or  local  conditions. 

6.  A  regenerative  circuit  is  more  de- 
pendent upon  the  proper  proportions  of 
the  units  used  than  upon  the  hookup.  If 
conditions  in  the  circuit  are  properly 
maintained  it  does  not  matter  whether 
regeneration  is  obtained  by  a  variometer, 
coupler,  tuned  impedance  or  by  capacity. 

7.  Selectivity  is  more  dependent  upon 
the  hookup  than  distance  or  signal 
strength.  A  hookup  in  a  large  measure 
determines  the  selectivity. 

Regenerative  Hookups 

8.  All  regenerative  hookups  are  prac- 
tically the  same  in  regard  to  signal 
strength  if  properly  proportioned  units 
are  used. 

9.  Distance    and    signal    strength    in- 


crease^at  a  smaller  rate  than  the  number 
of  tubes  employed.  Ten  tubes  will  not 
give  you  five  times  %the  range  or  volume 
given  by  two  tubes. 

10.  Selectivity  is  rougnly  proportional 
to  the  number  of  tubes  because  of  the 
greater  losses  introduced  by  the  greater 
number  of  tubes. 

11.  Tone  quality  diminishes  with  am- 
plification and  the  number  of  tubes  in  a 
given  type  of  circuit. 

12.  Tone  quality  decreases  as  signal 
strength  increases. 

13.  For  every  circuit  there  is  a  single 
optimum  wavelength  at  which  the  best 
volume  is  obtained. 

14.  For  every  circuit  there  is  a  single 
optimum  wavelength  at  which  the  best 
distance  is  obtained,  and  this  does  not 
necessarily  correspond  to  (13). 

15.  Selectivity  is  only  attained  by 
introducing  losses  into  the  circuit;  losses 
sufficient  to  render  the  undesired  station 
inaudible  when  the  circuit  is  brought 
into  a  condition  of  resonance  with  the 
desired  station. 

Cause  of  Weak  Signals 

16.  Amplification  is  largely  dependent 
upon  the  filament  emission  of  the  tubes. 
Weak  filament  emission — weak  signals. 

17.  Transformer  turn  ratios  do  not 
necessarily  determine  amplification  either 
at  radio  or  audio  frequencies. 

18.  Within  limits  amplification  in- 
creases with  the  plate  voltage.  This  is  a 
corollary  of  (16). 

19.  Dielectric  losses  are  not  of  great  im- 
portance at  high  radio  frequencies  or  short 
wavelengths.  They  are  of  more  import- 
ance on  long  waves  or  at  audio  frequency. 

20.  Skin  resistance  and  eddy  current 
losses  in  conductors  are  of  more  impor- 
tance at  short  wavelengths  and  high 
frequencies  than  the  dielectric  losses. 

21.  The  size  of  wire  is  not  of  great 
importance  so  far  as  the  conductivity  of 
radio  frequency  currents  is  concerned. 
A  large  wire  is  more  likely  to  cause  R.F. 
losses  than  a  small  one  as  indicated  at  (20). 

22.  A  resonant  circuit  is  a  resonant 
circuit  regardless  of  the  apparatus  used 
to  bring  about  this  condition. 


23.  Squealing  and  howling  circuits  are 
generally  indicative  of  range  or  distance 
getting  qualities. 

24.  Radio  frequency  amplifiers  are  not 
at  their  greatest  efficiency  when  com- 
pletely neutralized.  There  must  be  some 
tendency  toward  free  oscillation. 

25.  Radio  frequency  circuits  are  at 
their  best  when  the  detector  is  made 
regenerative. 

26.  A  detector  in  a  perfectly  neutral- 
ized circuit  can  be  made  regenerative 
only  with  difficulty.     See  (25). 

27.  All  circuits  must  be  at  least  slightly 
regenerative  to  obtain  maximum  dis- 
tance and  volume. 

28.  The  full  amplifying  efficiency  of  the 
tubes  is  never  realized  in  a  reflex  circuit. 

29.  The  "best  hookup"  found  by  the 
amateur  experimenter  usually  earns  this 
reputation  from  the  fact  that  better  pro- 
portioned units  were  used  with  this  circuit 
than  with  the  other  hookups  tried  out. 

Combinations  Vital 

30.  Commercial  apparatus  of  the  pre- 
sent day  is  inaccurate  in  regard  to  the 
rated  capacity,  inductance,  etc.;  hence 
certain  combinations  of  apparatus  will 
give  better  results  than  others  when  used 
in  different  hookups.  This  is  of  more 
importance  than  the  hookups  themselves. 

31.  Local  conditions  are  of  the  greatest 
importance.  With  the  same  receiver,  bet- 
ter reception  will  be  had  in  one  neighbor- 
hood than  in  another. 

32.  A  poor  aerial  and  ground  are 
responsible  for  more  trouble  than  all  of 
the  other  items  put  together. 

33.  Reception  in  the  open  country  is 
generally  much  better  than  in  a  city, 
providing  that  the  country  installation 
is  not  shielded  by  trees. 

34.  A  large  tree  full  of  sap,  and  a  steel 
building  are  about  equal  in  cutting  down 
reception.  Both  ground  the  waves. 
Maples  are  the  worst,  with  cottonwoods 
a  close  second. 

35.  Weakening  of  signals  and  shorten- 
ing of  range  in  Summer  begins  with  the 
first  appearance  of  foliage,  and  ends  when 
the  leaves  have  been  shed  in  the  fall. 

(Turn  io  page  58) 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


19 


m  Letters  from  a  Self-Made 
HI    'Radio  Fan  to 

•     His  Son  .:* 


In  Which  Beginners, 

Young  and  Old,  Are 

Given  Advice,  More 

or  Less  Amusing  and 

Instructive 


Bv  EDMUND 
H.  EITEL 


0  Chicago,  111.,  March  1,  1925. 

SCAR  Davenport, 
Valevard  College, 
New  Raven,  Conn. 

Dear  Oscar: 

Your  weekly  note  with  its  usual  re- 
quest for  funds  is  here,  and  I  take  my 
lobster-colored  pen  in  hand  to  make  out 
a  check  and  reply  to  you. 

There  is  one  unusual  feature  of  this 
last  note  of  yours,  and  I  commend  you 
for  it  heartily.  This  is  your  request 
for  an  extra  twenty-five  dollars  because 
you  have  become  interested  in  radio  and 
want  to  buy  the  parts  to  make  a  re- 
ceiving set. 

Accordingly,  1  take  you  at  your  word 
and  advise  you  to  confine  all  your  boot- 
leg purchases  in  the  future  to  bootleg 
tubes.  Son,  I  never  took  much  stock 
in  that  las"  invitation  of  yours  to  send 
you  seventy-five  dollars  to  get  "Doc" 
Eliot's  five-foot  shelf  of  champion  books 
in  Morocco,  because  it  did  not  sound 
sincere.  But  radio  is  different.  There 
you  strike  me  where  I  live,  as  your  radio- 
widowed  mother  will  inform  you. 

The  Greatest  Teacher 

T^O  SPEAK  seriously,  I  hope  and 
-*-  believe  you  will  plunge  into  radio 
like  the  old  swimmin'  hole.  Why?  First, 
because  you  can't  help  yourself — it  is 
the  most  interesting  thing  in  the  world. 
And  next,  because  it  is  this  world's 
greatest  teacher,  "Doc"  Eliot  himself 
not  omitted. 

Radio  can  teach  you  more  about  the 
mysteries  of  nature  in  one  month  than 
you'll  get  out  of  that  five-foot  shelf  by 
working  it   fifteen   minutes  a  day  for  the 


rest  of  your  life.  By  all  means,  get 
your  hands  into  radio.  The  way  to  learn 
a  lot  is  to  build  sets.  Build  one.  Then 
try  to  make  a  better  one.  Try  the  differ- 
ent systems.  You  will  get  a  college 
education  out  of  it,  believe  me. 

Here  are  a  few  of  the  things  building 
radio  sets  will  teach  you: 

How  to   think  for  yourself   (And   you 
certainly  need  it). 

How  to  buy  goods  intelligently. 
The  electrician's  trade. 
Electrical    engineering    principles. 
The     profound     electrical     secrets     of 
matter  and  energy. 

Insight  into  the  future  of  this  mar- 
velous scientific  era. 

And  besides  all  this,  it  will  tra'n  you 
in  patience  and  resourcefulness,  and  wi.l 
keep  you  indoors  nights!  It  appears  to 
me  that  radio  has  college  licked  in  every 
way.  It  does  all  this  for  a  fellow  be- 
cause the  first  principle  of  getting  edu- 
cated is  getting  vitally  interested.  I've 
often  told  you  how  quickly  we  all,  old 
or  young,  learned  soldiering,  engineering, 
aviation  and  what-not  during  the  war, 
in  the  various  army  schools.  When  a 
man  knew  his  life  might  depend  on  some 
bit  of  information,  he  seized  that  infor- 
mation for  keeps.  One  fellow  was  able 
to  recall  some  classroom  data  only  once 
mentioned,  several  months  later,  simply 
because  he  was  so  vitally  interested  in 
it  at  the  time. 

So  "please  find  enclosed"  a  check  for 
thirty-five  instead  of  twenty-five,  and 
mind  you,  spend  it  all  on  radio.  Your 
mother  is  sending  you  her  love  and  a 
pair  of  mittens  which  I  told  her  would 
go  well  with  that  big  fur  coat  you  college 
fellahs  wear. 


Your     affectionate 
father's  side. 


parent 


on     your 
DAD 


Chicago,  111.,  March  5,  1925. 
Dear  Os: 

Your  enthusiastic  response  to  my 
letter  and  check  touched  me  deeply. 
No,  I  would  not  build  a  super-hetero- 
dyne first.  For  this  reason  and  another 
one,  I  am  not  sending  the  money  for  that 
particular  kit  which  you  say  you  are  so 
crazy  to  acquire. 

I  like  your  suggestion  that  I  write  a 
few  letters  of  advice,  because  I  certainly 
ought  to  be  able  to  give  that.  If  a  radio 
manufacturer  himself,  with  all  the  ex- 
perience he  gets  competing  with  a  couple 
of  hundred  other  set-makers,  isn't  full 
of  advice,  then  he  must  be  full  of  prunes 
and  dead  from  his  O'Sullivans  to  his 
Stetson. 

Dad's  Experience  Helps 

T  CAN  tell  you  more  diseases  possessed 
■*■  by  such  simple  things  as  jacks  and 
rheostats  than  a  professor  of  therapeutics 
in  Johns  Hopkins'  Medical  School  could 
name  for  humanity.     Our  factory  has  to 


20 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hoiw 


w 


Posr 


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PcvSf     J.OUO  sp&n#&?  con  -  <&     .„,         ,        _  , 

JlsDePS     MOcOftJNECTtON 


M- 

A  B 


give  a  lot  of  attention  to  buying  radio 
and  I  am  going  to  tell  you  about  it  as 
reflected  from  our  experience. 

The  first  thing  you  ought  to  know  is 
exactly  what  you  want  and  then  exactly 
why _  you    want    it.      I   said   a   mouthful 


Fig.  1. 

in  laying  down  this  first  principle,  which 
after  all  is  a  sort  of  ideal  and  will  take 
many  months  to  attain. 

For  a  while  you  can't  hope  to  know  as 
much  as  the  clerk  who  waits  on  you, 
and  you'll  have  to  take  his  word  for  sev- 
eral things.  There  are  clerks  and  clerks, 
and  when  you  find  a  good  one,  you  have 
made  a  real  friend;  so  go  to  a  reliable 
dealer,  since  he  backs  up  his  clerks.  The 
word  reliable  means  dependable.  You 
can  return  apparatus  which  does  not 
work  to  an  honest,  sincere  merchant. 
If  our  company  makes  it  a'  rule  to  deal 
only  with  firms  of  reputation,  it  must 
be  a  good  rule  for  the  individual  to  follow, 
even  though  he  buys  no  more  than  a 
single-circuit  jack. 

The  next  point  is  to  buy  goods  of 
reputation.  If  I  say,  "with  good  will" 
you  will  approve  at  once,  but  if  I  say 
"consistently  advertised"  you  may  not 
follow  me.  In  our  factory  we  have  ex- 
pensive testing  instruments  and  can 
afford  to  buy  anywhere,  and  yet  we  do 
not.  We  buy  only  goods  of  the  best 
name  because  that  is  the  only  way  to 
keep  out  of  pecks  of  trouble. 

So  don  t  spend  my  money  on  unadver- 
tised  goods,  but  learn  to  discriminate 
in  reading  advertisements.  Where  there's 
a  lot  of  smoke  there's  some  fire.  This 
is  principle  number  one:  but  don't 
follow  it  too  religiously.  If  you  see  the 
article  consistentlv  advertised,  then  read 


Fig.  2. 

the  claims  made  for  it  and  compare 
them  with  other  claims.  This  is  the  test 
of  reason. 

You  can  furthermore  make  the  test  of 
sincerity.  If  a  firm  claims  for  example 
that  its  receiver  is  the  best,  gets  the 
longest  distance,  the  greatest  volume, 
the  purest  tone,  and  still  is  the  simplest 
to  operate,  you  can  be  sure  that  the 
advertising  agency  of  Ananias  &  Munch- 
hausen  have  written  that  ad.  Judge 
an  advertisement  exactly  as  you  would 
any  man  or  boy  you  meet.  It.  won't 
take  you  long  to  discriminate  between 
sincerity  and  boasting. 


Fig.  3. 

"Something  for  Nothing" 

ONE  more  point  about  buying — don't 
waste  my  money,  son,  by  trying 
to  get  something  for  nothing.  You 
can't  do  it.  Cheap  goods  are  usually 
cheap  performers.  You  can  buy  a  cheap 
jack  and  save  fifteen  cents  and  when 
its  insulation  fails  you  can  burn  out 
fifteen   dollars  worth   of  tubes!      Or  vou 


-W/WA 


® 


can  save  a  couple  of  dollars  on  a  con- 
denser and  make  a  set  which  can't  reach 
out  over  five  hundred  miles.  Do  you 
know  that  our  factory  does  not  try  to 
buy  goods  at  the  lowest  possible  price? 
We  find  that  in  the  long  run  we  get 
what  we  pay  for  and  as  we  want  to  make 
the  best,  we  have  to  pay  the  price,  and 
so  will  you. 

This  is  radio  lessorl  number  one,  a 
lesson  in  business,  a  lesson  in  buying. 
This  is  surely  an  important  lesson,  for 
you  are  spending  a  lot  of  my  money  and 
will  one  day  be  reduced  to  the  painful 
necessity  of  earning  what  you  spend  by 
the  sweat  of  your  own  brow. 

Good-night,    old     man,     I     must    now 
close,  as  I  have  a  radio  engagement  with 
the    Kansas    City    Night-hawks   and   the 
wee-small    hours    are    here. 
Affectionately, 

"Dad." 


Chicago,  111.,  March  10,  1925. 
Dear  Old  Son: 

You    know    how    I     rest     my    electric 


Fig.   4. 

soldering  iron  on  the  little  old  upright 
ash-tray  and  sinoke  while  I  work  at 
radio!  Well,  I  had  just  laid  down  my 
cigar  when  your  Mother  handed  me  this 
last  letter  of  yours,  artd  it  got  me  so 
excited  that  I  picked  up  the  hot  soldering 
iron  afterward  instead  of  my  cigar.  So 
if  you  have  trouble  reading  this,  you'll 
know  why. 

What   got    me    "jumpy"   when   I   read 

your    letter     was    the    way    that    clerk 

handed    you    that    old    junk    inductance 

of   the   year    1923.      So    far   as   efficient 

(Turn  to  page  59) 


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RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


21 


How  to  Get  Rid  of  SQUEALS  and 
Interference 


Simple  Wave 

Trap  Cuts  Out  the 

Strong  Locals;  Fixed 

Condenser  Helps 

Clarity 


It's  the  seeming  trifles  in  radio  construc- 
tion that  usually  cause  the  most  trouble 
when  you  start  to  wonder  why  the  outfit 
doesn't  work  as  well  as  it  was  advertised 
to  do.  The  chances  are  that  the  fault  is 
with  the  layout  or  the  construction,  ij  the 
parts  are  home-made;  so  if  you're  inclined 
to  condemn  the  originator  of  the  circuit, 
just  ask  yourself  whether  you  overlooked 
something  that  usually  is  taken  for  granted. 
The  accompanying  photos  point  out  some 
of  the  "trifling"  details  of  set  operation  and 
construction. 


If  you're  annoyed  by  squeals  in  your 
set,  maybe  it's  the  fault  of  your  amplifier. 
If  so,  here's  a  sure  cure.  If  the  second 
step  of  your  audio  amplifier  causes  a 
high  pitched  squeal  that  doesn't  seem 
logical,  eliminate  it  by  placing  a  .00025 
fixed  condenser  across  the  secondary  of 
the  transformer.  This  should  not^  only 
eliminate  the  squeal,  but  should  improve 
the  quality  of  your  reception  as  well. 
The  photo  shows  how  to  place  the  condenser 
on  the  A.  F.  transformer. 

tKadel  £  Herbert  Photos) 


To  make  an  efficient  and  simple  wave  trap  which  will  reduce  interference  and  elimi- 
nate that  troublesome  local  station  near  you,  a  honeycomb  coil  and  a  condenser  will  be 
all  the  materials  that  are  required.  A  75-turn  honeycomb  coil  connected  in  parallel  with 
twenty-three  3-plate  condenser,  will  make  a  very  efficient  wave  trap.  After  the  coil  and 
the  condenser  have  been  connected  as  shoivn  above,  the  trap  should  be  connected  in  series 
ivith  your  antenna.  If  the  set  fails  to  cover  the  higher  wavelengths  with  the  trap  connected, 
a  coil  with  a  larger  number  of  turns  can  be  substituted. 


The  tips  at  the  ends  of  your  phone  and  loud  speaker  cords  are  not  any  too  strong,  and 
they  come  off  quite  easily  when  they  are  jerked  out  of  the  jacks  by  the  cords  by  many 
radio  fans.  That  extra  string  between  the  cords  was  placed  there  for  a  purpose,  but  only 
a  few  fans  know  why.  As  a  result  they  cut  it  off  to  get  it  "out  of  the  way."  The  photo 
shows  how  this  extra  string  can  be  and  should  be  put  to  use.  Tie  it  to  the  phone  plug  as 
shown,  so  that  all  the  pull  will  be  on  the  string  when  the  plug  is  being  jerked  out  of  the 
jack. 


22  RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


"This  is  Billy  Rumford  in  camp,, 
Charley,"  the  honey  mooner  announced. 
"Tune   down   to   150.      I   want   to   talk   to 

you."    ' 

(Continued  from  March  Radio  Age)\ 

THEN  he  shut  off  the  transmitter 
in  order  that  he  might  catch  the 
effect  of  his  order  on  the  burglars. 
A  confusion  of  utterances  was  distinctly 
audible.  All  the  campers  now  listened 
with  the  eagerness  of  an  audience  at  a 
comic    melodrama. 

"Now,  quiet,"  Billy  continued.  "I'm 
going  to  give  'em  some  more." 

Over  went  the  switch  again,  and  the 
next  instant  he  was  pouring  more  "terror" 
into  the  burglar-infested  room: 

"Drop  all  that  silverware  and  jewelry, 
or  I'll  shoot  you  dead  in  your  tracks. 
I'm  concealed  where  you  can't  find  me, 
with  an  automatic  in  my  hand.  I'll 
count  one,  two  and  three,  and  if  you 
haven't  gone  by  that  time  without  taking 
anything  with   you,    I'll  shoot." 

Back  went  the  switch  once  more  in 
time  to  catch  several  coarse  utterances 
through  the  loud  speaker.  Then — one — 
two — three — muffled  explosions  were 
heard,  like  pistol,  shots  in  a  sealed  room, 
heard  on  the  outside  through  a  heavy  door. 

Alice  uttered  a  sharp  little  scream, 
and  every  face  in  camp  became  a  shade 
or  two  paler  in  the  head-light  illumina- 
tion. 

"What  do  you  suppose  that  was?" 
asked   Marie,   with  a  shiver. 

"They  shot  at  me,"  Billy  replied  with 
the  cool  nerve  of  "radio  distance."  "W  hat 
shall  I  do — give  a  death  groan  for  their 
benefit   into   the   microphone?" 

"No,  laugh  at  them,"  said  Carl.  "Tell 
them  you  have  a  charmed  life  and  they 
can't  kill  you.     Make  fun  of  them." 

"Oh,  Carl!"  exclaimed  his  wife,  laugh- 
ing  hysterically. 

"The  very  idea,"  complimented  Billy. 
"I'll  have  'em  going  mad  for  a  bug- 
house." Then  into  the  microphone  he 
called: 

"Ha!  ha!  ha!  Those  bullets  tasted 
good.  I  caught  every  one  of  them  in  my 
mouth.  Shoot  again.  I'll  eat  all  you 
can  send.  I  won't  shoot  till  you've 
emptied  your  pistols.     Fire  away." 

"Bang!  bang!  bang!"  came  the  answer, 


The  Sleuths  of 
Honeymoon  Camp 


The  Radio  Honeymooners  Thought 
Their  Burglar  Snare  was  Complete, 
But  the  Two  Burglars  Laughed  Last 

By  FRANK  HONEYWELL 


as  Billy  closed  the  switch,  three  more 
shots  in  succession.  Then  a  few  mo- 
ments of  silence,  followed  by  anothe  shot. 

"Ha,  ha,  ha,  ha!"  laughed  Billy  with 
"all  his  lungs,"  with  hand  still  working 
the  switch,  of  course.  "Oh,  but  those 
bullets  tasted  good.  Load  up  again  and 
fire  some  more.  Oh,  what  an  appetite 
I  have  for  steel-jacketed  bullets!  They 
taste  just  like  Boston  baked  beans,  with 
lots  of  red  pepper  added,  only  I  can't 
get  a  mouthful  from  those  pea-shooters 
of  yours.  Haven't  you  got  a  blunder- 
buss  or   a   cannon?" 

"They'll  hit  the  loud  speaker  there 
in  its  'throat'  next,  and  then  your  game'U 
be  up,"  whispered  Jerry  in  Billy's  ear. 

Terror  Reigns 

A  S  THE  switch  went  back  for  receiv- 
^  *-  ing,     a     wild     scream     greeted     the 


What's  Gone  Before 

THREE  newly  married  couples — 
Billy  and  Helen  Rumford; 
Jerry  and  .Alice  Anderson,  and 
Carl  and  Marie  Frisbee — lake  a 
motor  trip  fifty  miles  from  home  and 
establish  a  "Honeymoon  Camp." 
They  have  a  radio  telephone,  the 
generator  of  ivhich  is  operated  with 
an  automobile  engine.  While  listen- 
ing- in  on  the  first  evening  of  the 
honeymoon,  they  hear  voices,  seem- 
ingly belonging  to  two  burglars 
making  an  inventory  of  silverware 
they  have  found  in  the  home  of  Alice 
Ramford's  father.  This  conversa- 
tion takes  place  before  the  micro- 
phone of  the  radiophone  of  Alice's 
brother,  who  has  perfected  a  burglar 
alarm  and  automatic  switch  for 
sending  and  receiving  and  connected 
it  with  his  outfit.  Billy  attempts  to 
scare  the  burglars  by  calling  into  his 
microphone:  "Hands  up,  or  I'll 
shoot!" 

Now  read  the  Story 


campers  from  the  horn,  followed  by  a 
voice  toned  with  panic: 

"Come  on,  Bimbo;  I'm  going  to  get 
out  of  here.     This  is  too  much  fer  me." 

"Oh,  come  back,  Sam,"  was  the  other's 
reply.      "Can't    you    guess    what    it    is? 


It's  somebody  talkin'  in  the  radio.  See — 
I  got  my  flashlight  on  it  now.  That's 
where  the  voice  comes  from." 

There  was  silence  a  few  moments, 
followed  by  indistinct  conversation,  the 
drift  of  which  seemed  to  be  that  "Bim- 
bo's" explanation  of  the  mystery  was 
satisfactory  to   both. 

"We  better  hustle  out  o'  here,"  one  of 
them  said.  "Somebody  may  'ave  heard 
those    shots." 

"Not  much  danger,"  the  other  replied. 
"The  nearest  house  is  half  a  block  from 
here,  and  every  house  within  a  block  is 
dark — -nobody  home.  Let's  hunt  around 
and  see  what  more  we  can  find." 

"I'm  going  to  see  if  I  can  get  Charley 
Patterson  on  the  wireless,"  said  Billy, 
addressing    the    "honeymoon    campers." 

"Let's  see;  he  usually  sends  at  about 
160.  I'll  try  that  first,  both  sending  and 
receiving." 

His  effort  was  rewarded  with  success. 
Charley  happened  to  be  listening  in  on 
an  amateur  wavelength  slightly  below 
that  to  which  Alice's  brothers'  outfit  was 

(Turn  to  page  62) 


"All  right,"  answered  Charley.  "Down 
we  go."  A  few  moments  later  they  were 
conversing  on  a  wavelength  that  could  not 
be  received  by  Alice's  brother's  super- 
heterodyne. 


RADIO  AGE  for  April,   1925 


What  the  Broadcasters  are  Doing 


23 


Photo  by  Drake  Studio 


CHARMING  THE  MULTITUDES 

Miss  Yukona  Cameron,  shown  above  in  a  bewitching  pose,  has 
recently  come  into  favor  among  the  fans  who  listen  nightly  to  WQJ, 
the  Calumet-Rainbo  station  at  Chicago.  Miss  Cameron  often  favors 
her  audience  with  old-time  selections,  but  she  receives  the  most 
requests  when  she  presents  a  popular  ditty.  She's  a  regular  attrac- 
tion at   WQJ  now. 


24  RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doing 


What  the 

Br  oadc  asters 

are  Doing 


"Roxy"  Decides  Not  to 
Fight  Radio 

NEW  YORK:— Roxy,  the  smart 
showman,  hasn't  any  grudge  against 
radio,  for  it  is  rapidly  making  him  one 
of  the  most  famous  men  of  the  country. 

Other  moving  picture  impresarios  and 
theater  managers  are  setting  up  a  hulla- 
baloo about  the  possibility  of  radio's 
ruining  their  business,  but  Roxy,  with 
foresight,  has  succeeded  in  harnessing  it 
to  the  business  office  in  the  most  amazing 
manner. 

Instead  of  advocating  that  performers 
keep  off  the  air,  he  not  only  takes  the 
opportunity  of  putting  his  performers  on 
the  air,  but  actually  gives  free  of  charge 
twice  as  long  a  musical  program  as  may 
be  heard  in  the  theater  by  those  attend- 
ing the  performance. 

At  that,  such  multitudes  seek  admission 
to  the  moving  picture  theater,  which,  by 
the  way,  is  located  in  New  York  and  is 
said  to  be  the  largest  in  the  world,  that 
thousands  are  turned  away  nightly  and 
enormous  lines  of  standees  are  the  rule. 

Roxy's  concerts  are  simultaneously 
broadcast  each  Sunday  night  through 
stations  WEAF,  New  York  City;  WCAP, 
Washington,  D.  C;  WJAR,  Providence, 
R.  I.;  WEEI,  Boston,  Mass.;  and  WDBH, 
Worcester,  Mass.  Also  at  times  through 
WGR,  Buffalo,  N.  Y.;  WFI,  Philadel- 
phia, Pa.;  and  WCAE,  Pittsburgh,  Pa. 
A  Night  in  Roxy's  Studio 

The  musical  part  of  the  theater  program 
is  put  on  the  air,  but  when  the  feature 
picture  comes  the  program  is  shifted  to 
the  large  studio  upstairs  and  here  Roxy 
may  be  seen  at  his  best. 

It  is  an  unusually  large  room  with 
black  walls  and  heavy  gray  absorbing 
draperies  hung  around,  much  the  same 
as  draperies  in  a  photograph  gallery.  In 
addition  to  the  microphone  in  the  corner, 
there  are  several  other  microphones  in 
the  ceiling  to  absorb  the  volume  of  sound 
from  the  orchestra. 

Immaculately  attired,  .Roxy  is  as  he 
would  be  if  he  were  actually  appearing 
before  his  audience,  but  amid  the  odd 
surroundings  some  of  the  performers  are 
in  evening  dress,  others  in  stage  costumes 
and  make-up,  with  a  fringe  of  favored 
listeners  who  watch  the  strange  broad- 
casting with  bated  breath,  for  silence  is 
the  predominating  note  everywhere. 

To  the  listeners  on  the  air  the  perform- 
ance runs  with  an  almost  monotonous 
continuity  at  times.  However,  the  nerv- 
ous strain  in  the  studio  in  putting  on  one 
of  these  performances  of  "Roxy  and  His 
Gang"  is  terrific. 


New  Dramatic  Soprano 
at  WSOE 

A  POPULAR  new  dramatic  soprano 
has  made  her  advent  at  Station 
WSOE,  operated  by  the  School  of  Engin- 
eering at  Milwaukee,  Wis.,  on  a  wave- 
length of  246  meters. 

She  is  Miss  Nathalie  Unke,  and  her 
picture  is  shown  in  the  inset  above. 
Miss  Unke  has  appeared  from  WSOE 
only  a  few  times  recently,  but  her  singing 
of  old-time  popular  numbers  as  well  as 
operas  has  made  her  a  favorite. 


Movie  fans  were  recently  given  the  chance  to 
*'hear"  the  actual  making  of  a  motion  picture. 
Portions  of  the  "audible"  scenes  of  "The  Mad 
Dancer,"  in  which  Vincent  Lopez,  orchestra  im- 
presario and  Ann  Pennington,  Follies  Dancer,  are 
playing  the  leads,  were  broadcast  recently  from 
WJZ.  The  fans  not  only  hear  what  the  actors  are 
saying,  but  the  directors'  and  technical  staffs'  in- 
structions as  well,  thus  giving  a  real  insight  into 
movie  making.  The  photo  shows  Ann  Pennington 
dancing  atop  a  piano  in  one  of  the  scenes. 
(Kadel  and  Herbert  Photo.) 


"Cavalier a  Rusticana"  on 
Air  From  WGBS 

\  N  EVENT  without  precedent  in  the 
-'■*-  field  of  radio  took  place  Sunday 
night,  February  8th,  when  Mascagni's 
famous  opera,  "Cavallera  Rusticana,  "was 
broadcast  from  Station  WGBS,  New 
York,  with  a  full  cast  of  distinguished 
operatic  voices  and  a  complete  profess- 
ional operatic  chorus,  accompanied  by 
an  operatic  orchestra. 

The  broadcasting  of  this  opera,  which 
is  in  the  nature  of  an  experiment  and 
will  be  followed  by  other  of  the  best 
known  operas  with  even  more  prominent 
singers,  was  arranged  by  Corrien  D' 
America,  the  leading  Italian  newspaper 
published  in  this  country,  and  in  particular 
by  Luigi  Barzini,  its  editor.  It  was  a  radio 
treatment  of  the  opera  that  was  heard, 
especially  planned  for  the  listeners-in, 
and  the  entire  musical  score  was  given 
together  with  a  libretto  and  scenic  synop- 
sis particularly  devised  for  this  unique 
presentation.  This  is  the  first  time  in 
the  history  of  radio  that  an  opera  has 
been  broadcast  in  such  manner,  with  such 
a  cast  singing  the  various  roles. 

Gieseppe  Reschiglian,  celebrated  Ital- 
ian singer,  had  the  tenor  role  of  Turridu. 
Oaterina  Gobbi,  soprano,  well  known  in 
Europe  in  concert  and  operatic  fields,  sang 
the  role  of  Santuzza.  Silvio  Sideli, 
famous  concert  baritone,  who  has  just 
come  to  this  country  after  considerable 
success  in  London,  sang  Alfio.  Maria 
Wrape,  contralto  in  the  role  of  Sola,  and 
Lavinia  Puglioli,  mezzo-soprano,  the  role 
of  Mamma  Lucia.  The  Conductor  was 
Antonio  Dell'  Orefice  and  the  opera  was 
given  under  supervision  of  Philip  F. 
Ienni,  Manager  of  Puccini  Grand  Opera 
Co. 

Zuigi  Barzini,  responsible  for  the 
arrangements,  declared  that  the  broad- 
casting of  "Cavallera  Rusticana"  was 
planned  purely  as  an  educational  measure. 

"Statistics  show  that  in  New  York  there 
are  scarcely  8,000  people  who  are  habitual 
opera-goers,"  Mr.  Barzini  said.  "And  out 
of  all  the  inhabitants  of  this  huge  metro- 
polis there  are  about  60,000  who  see  an 
opera  ocasionally.  And  figures  indicating 
nation-wide  attendance  are  just  as  low. 
There  are  hardly  500,000  of  the  entire 
population  of  the  United  States,  roughly 
estimated,  that  have  any  knowledge 
whatsoever  of  opera. 

"All  the  rest  of  our  people  do  not  know 
what  opera  is.  They  keep  away,  the 
rest  of  them,  because  they  are  afraid  they 
will  not  understand  it.  They  don't 
know   opera  because  they   don't  go." 


RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doing. 


The  Interesting  Story  of  The 

Way  Station  KGW,  at 

Portland,   Oregon, 

Is  "Screeching" 

The  Glories  of 

The  West  to 

Radioland  m 


Keep 

Growing 

WISER 

with  the 

"HOOT 

OWLS 


*  i 


By 
"DICK"  H ALTER 

Director,  Station 
KGW 


HOOT!  HOOT!"  Out  in  Portland, 
Oregon,  where  Station  KGW,  of 
the  Portland  Oregonian  is  Lord  of 
the  Ether,  the  foregoing  Owl'sexclamation 
is  the  signal  for  all  the  fans  to  settle  down 
in  the  old  easy  chair  for  the  evening  and 
stay  awake  till  the  milkman's  wagon 
clatters  up  the  street. 

And  Friday  night,  from  10:30  o'clock 
until  the  Lord  knows  when,  the  "Hoot 
Owls"  climb  into  their  tower  in  the 
Oregonian  building  and  broadcast  a  bit 
of  nonsense  that  has  never  been  dupli- 
cated for  its  originality,  cheerfulness  and 
carefree  abandon. 

Of  course,  in  the  East  and  Middle 
-  West  the  fans  have  their  "Nighthawks," 
"Insomnia  Clubs"  and  "Mythical  Diri- 
gible" organizations,  but  they  are  rarely 
heard  out  where  the  West  holds  sway. 
In  fact,  the  fans  are  so  absorbed  in  what 
the  "Hoot  Owls"  are  going  to  do  next 
that   they   have   little   interest   in   what's 


going  on  in  the  remainder  of  the  broad- 
casting world  outside  of  Portland. 

A  Pacific  Pioneer 

KGW  was  one  of  the  pioneer  radio 
stations  on  the  Pacific  Coast,  and 
now,  with  KFI,  KGO  and  one  or  two 
others,  it  holds  undisputed  Pacific  Coast 
leadership  for  the  variety  of  its  programs 
and  the  quality  of  their  arrangement. 
KGW  is  now  operating  on  a  wavelength 
of  385  meters,  which  is  pretty  convenient 
for  the  fans  in  that  section  of  the  country. 
The  idea  of  the  "Hoot  Owls"  was  con- 
ceived early  in  KGW's  history,  when  it 
became  evident  that  some  kind  of  human 
interest  feature  would  have  to  be  estab- 
lished to  keep  the  listeners  bound 
together  in  one,  big  amiable  family.  As 
a  result  a  staff  of  "Owls"  was  organized, 
and  today  it  is  known  up  and  down  the 
Pacific  coast  and  even  in  the  East  for 
the    efficient    and    business-like    way    in 


The  "Degree 
Team"  of  the 
Famous  Order 
4*i*     of  "Hoot  Owls:" 
py        Top,    Charles    F. 
*      Berg,  grand  screech; 
clockwise:  Frank  J.  Sar- 
dam,  grand  scream;  Ash- 
ley C.  Dixon,  grand  scratch; 
Henry  W.  Metzger,  grand  slam: 
Dean  Collins,  grand   sonnet;  Dick 
Haller,  holder  of  the  grand  goat;  Wil- 
liam Robinson  Boone,  grand  skipano;  Bar- 
nett  H.  Goldstein,  grand  schmoos;  "Tige"  Rey- 
nolds, grand  sketch;  Steve  Johasz,  grand  slumber. 


which  it  deals  out  tom-iooiery.  Charles 
F.  Berg  of  the  Oregonian  was  appointed 
"Grand  Screech"  of  the  Keep  Growing 
Wiser  Order  of  Hoot  Owls,  and  under 
him  is  a  galaxy  of  newspapermen  and 
radio  experts  who  fill  the  more  or  less 
comical  roles  of  Grand  Scream;  Grand 
Scratch;  Grand  Slam;  Grand  Skipano; 
Grand  Schmoos;  Grand  Sketch,  Grand 
Slumber  and  countless  others  equally 
crazy. 

Every  time  a  new  KGW  listener  is 
initiated  into  the  "Hoot  Owls"  club, 
he  must  suffer  an  ethereal  bombard- 
ment at  the  hands  of  the  "officials" 
named  above.  And  what  the  "Grand 
boys"  devise  to  create  a  tingle  in  the 
"candidate's"  veins  can  be  appreciated 
only  by  actually  listening  in.  Needless 
to  say,  a  radio  fan  goes  around  bragging 
for  a  week  after  being  duly  initiated  via 
the  air  route. 

(Turn  to  page  65) 


26 


RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doing 


s: 


The  Original  Night-Hawks 
Garner  Some  Votes 


TATION 
KYW  and 
the  Con- 
gress Hotel  claim 
distinction  in 
introducing  an 
orchestra  as  a 
favorite  for  the 
current  monthly 
contest.  During 
the  hectic  period 
from  December 
16  to  January 
15,  when  for  the 
first  time  in  four 
months  there 
came  a  readjust- 
ment of  the  three 
leaders,  Coon  and 
Sanders'  Original 
Nighthawks  not 
only  scored  the 
greatest  vote  for 
the  month  but 
found  a  berth  in 
third  place  of 
the  major  con- 
test. 

The  original 
"Nighthawks" 
form  what  is 
perhaps  the  best 
known  radio  or- 
chestra in  the 
country.  As  their 
name  implies,  they  started  their  spurt  to 
fame  with  the  famous  Kansas  City  Night- 
hawks  Club  from  Station  WDAF,  of  the 
Kansas  City  Star.  After  several  months 
with  that  aggregation,  the  Coon  and 
Sanders'  boys  decided  to  branch  out  for 
themselves  as  the  "Original  Nighthawks." 

Under  that  banner  they  headed  Chi- 
cago-ward and  capitalized  on  the  reputa- 
tion earned  by  radio  at  several  of  Chi- 
cago's best  known  cabarets,  theaters 
and  other  entertainment  places.  Finally, 
their  name  firmly  established  in  that 
city,  they  joined  the  Congress  Hotel  as 
the  sole  furnishers  of  syncopation  in  the 
famous  "Balloon  Room"  of  the  well- 
known    hostelry. 

Almost  immediately  the  "Nighthawks" 
were  hooked  up  with  the  Congress  Hotel 
Studio  of  KYW,  and  soon  their  entranc- 
ing music  was  once  more  on  the  air  for 
the  multitude  of  fans  who  "Wondered 
what  had  become  of  the  Nighthawks." 
The  Nighthawks  went  Sally  one  better 
and  told  everybody  where  they  had  been. 

A  New  Radio  Club 

\  FTER  several  months  of  broadcast- 
-^*-  ing  from  the  Congress  Studio  of 
KYW",    Coon    and    Sanders    have    intro- 


By  Harry  Aldine 


J   ;& 

mm 

lilt 


The  serious-visaged  young  men  above  compose  Coon  and  Sanders'  Original  Nighthawk 
Orchestra,  who  now  contribute  largely  to  the  success  of  the  "Insomnia  Club"  from  1  to 
Z  a.  m.  daily  at  Station  KYW,  Congress  Hotel,  Chicago. 


Radio  Age  Contest 
to  Close  on  June  15 


POPULARITY  CONTEST  COUPON 

Harry  Aldine,  Contest  Editor 

RADIO  AGE,  500  N.  Dearborn  St.,  Chicago. 

I  wish  to  cast  my  vote  for: 

Name  of  favorite. . _ _ 

Classification _ __". „ 


Station Date  Heard... 

Name  [optional] _ _ 

Address  [optional].. 


duced  a  new  feature  similar  to  the  Night- 
hawk  frolic  which  they  originated  at 
WDAF  a  few  years  ago.  It  is  fast  gain- 
ing in  favor  among  the  fans  and  brings 
to  Chicago  its  first  "Radio  Club"  such 
as  the  "Hoot  Owls"  of  Portland,  Ore., 
the  "Red  Apple  Club"  of  WCX  and  the 
"Mythical   Dirgible"   Club  of  WCAE. 

KYW's  matutinal  feature  of  an  hour 
of  dance  music  and  fun  from  the  Balloon 
Room  of  the  Congress  Hotel  in  Chicago 
is  already  an  established  success  judging 
from  the  letters,  cards  and  telegrams 
which  have  begun  to  pour  in  at  the 
Congress    Hotel. 

This  past  midnight  stunt,  originally 
known  as  the  "Midnight  Sons,"  has 
been  changed  to  the  "Insomnia  Club" 
since  the  latter  name  is  more  in  keeping 
with  Coon-Sanders'  Original  Nighthawks' 
music  from  one  to  two  o'clock  in  the 
morning,  every  morning,  except  Monday 
and  Tuesday. 

Heretofore  KYW  used  to  pick  Coon- 
Sanders'  orchestra  at 
odd  times,  playing 
from  the  Balloon 
Room  of  the  Congress, 
but  the  demand  for 
more  of  this  type  of 
music  became  so  in- 
sistent that  KYW  de- 
cided to  put  on  this 
new  feature  from  1 
to  2  a.  m.  in  order 
to  give  listeners-in  on 
both  coasts  and  else- 
where   more  music 


and  a  better 
opportunity  for 
enjoyment  of 
early  morning 
broadcasting. 

Between  the 
dance  numbers, 
which  of  course 
are  being  played 
lor  the  guests  of 
the  Balloon 
Room  at  the  Con- 
gress, Fred  A. 
Hill  of  the  engi- 
neering staff  of 
KYW,  acts  as  an- 
nouncer. Joe  L. 
Sanders,  director 
of  the  orchestra, 
and  Carleton 
Coon,  the  orig- 
inal "Professor" 
of  the  Kansas 
City  Night- 
hawks,  together 
with  the  an- 
nouncer manage 
to  pull  quite  a 
bit  of  impromptu 
entertain  ment 
for  the  benefit  of 
their  invisible 
audience. 

Indicative  of 
the  popularity  of 
the  "Insomnia  Club"  among  fans  from 
coast  to  coast,  is  the  fact  that  during  the 
hour  each  night  when  it  is  in  session, 
nearly  every  dance  selection  played  in 
the  Balloon  Room  is  at  the  request  of 
some  one  of  the  radio  listeners. 

Especially  heavy  response  from  the 
West  Coast  has  been  noted,  with  a  good 
sprinkling  of  Canadians  and  residents 
of  the   East   Coast. 

All  aboard  for  the  next  Insomnia 
Special — no    Pullmans. 

THE  WINNER  FOR  FEBRUARY 

Coon-Sanders'      Orchestra,      Entertainers 

.._ KYW,     Chicago 

WINNERS  OF  PRECEDING  MONTHS 

July Duncan   Sisters,    KYW 

August „ Bill    Hay,    KFKX 

September Karl     Bonawitz,      WIP 

October H.  W.  Arlin,  KDKA 

November. „ .Bert    Davis,    WQJ 

December Jack  Nelson,  WJJD 

January Art  Linick,  KYW 

STANDING   TO   FEBRUARY    15 

Name  and  Classification  Where  Heard 

Karl    Bonawitz,    Organist. WIP,    Philadelphia 

Bill     Hay,     Announcer KFKX,     Hastings 

Coon-Sanders'      Nighthawks,      Orchestra 

KYW,  Chicago 

H.  W.  Arlin,  Announcer KDKA,  Pittsburgh 

Bert    Davis,    Entertainer WQJ,    Chicago 

Harry   M.   Snodgrass,   Entertainer. 

WOS,     Jefferson     City 

Jack  Nelson,   Announcer WJJD,   Mooseheart 

Art  Linick,  Entertainer KYW,  Chicago 

Duncan  Sisters,  Entertainers.,. KYW,  Chicago 

Ford  and  Glenn,  Entertainers WLS,  Chicago 

Lambdin  Kay,  Announcer. WSB,  Atlanta 

John  S.   Dagget,   Announcer KHJ,   Los  Angeles 

J.  Remington  Welsch,  Organist KYW,  Chicago 

E.  L.  Tyson,  Announcer WWJ,  Detroit 

Hired  Hand,  Announcer WBAP,  Fort  Worth 

Fred    Smith,    Announcer WLW,    Cincinnati 

Jerry  Sullivan,    Announcer-Entertainer 

WQJ,     Chicago 

Nick  B.  Harris,   Entertainer KFI,   Los  Angeles 

Edward    H.    Smith,    Director-Player 

WGY,     Schenectady 

"Sen"  Kaney,  Announcer KYW,  Chicago 

Wendell  Hall,  Entertainer WDAF,  Kansas  City 

Howard  Milholland,  Announcer KGO,  Oakland 

Scottish  Rite  Orchestra,. KGO,  Oakland 

Banks  Kennedy.  Entertainer WEBH,  Chicago 

S.  Hastings,  Announcer    KFI,  L03  Angeles 

Robert  Boniel,  Announcer WEBH,  Chicago 


(Turn  to  Page  66) 


RADIO  AGE  for  April,  1925 

How  One  Ambitious 
Girl  Became  Famous 

Radio's 
"  Leading 

LADY" 


iS-Y ear-Old  Rosaline 

Greene  of  WGY 

Players  Reaches 

Pinnacle  of 

Career  as  America  s 

Premier 

"Radio  Theater"  Actress 


IF  YOU  think  you  have  talent  and 
want  a  place  back  of  the  footlights, 
don't  invite  disappointment  and 
perhaps  starvation  by  seeking  interviews 
with  a  producing  manager,  casting  direct- 
or, author  or  agency.  Send  him  a  sample 
of  your  voice  by  radio. 

This  system  may  not  always  work. 
There  is  always  the  chance  that  the 
manager  will  not  be  listening.  However, 
it  was  successful  with  Rosaline  Greene, 
the  eighteen-year-old  leading  woman 
of  the  WGY  Players,  the  group  which  is 
weekly  broadcasting  a  play  from  the 
eastern  station  of  the  General  Electric 
Company  at  Schenectady,  N.  Y. 

Early  this  Fall,  Selwyn  &  Company 
offered  the  WGY  Players  the  privilege  of 
producing  "Silence,"  a  crook  play  by 
Max  Marcin.  The  play  was  then  in 
rehearsal  in  New  York  and  the  manage- 
ment believed  that  its  production  on  the 
air,  prior  to  the  premiere  on  the  stage, 
would  give  a  fair  indication  of  its  enter- 
tainment value. 

It  so  happened  that  Rosaline  Greene 
was  selected  for  the  leading  female  role. 
Max  Marcin,  the  author,  listened  to  the 
radio  performance  and  found  it  good. 
He  was  particularly  char-med  by  the 
voice  of  the  young  woman  playing  the 
lead.  A  few  days  later,  Miss  Greene 
received  an  invitation  to  understudy 
the  lead  in  the  stage  production,  in  spite 


What  the  Broadcasters  are  Doing  27 


Hard-Hear  ted 
Forest  Ranger 
is  Stirred  to 
Tears  by  Her 
Realistic  Act 
in  Radio  Drama 


Here  is  an  attractive 
pose  of  Miss  Greene  as 
she  appeared  "in  cos- 
tume" for  one  of  WGY's 
recent  radio  productions. 


of  the  fact  that  she  had  never  been  inside 
the  office  of  the  producing  manager. 

Her  First  Real  Offer 

'"PHE  offer  was  alluring.  It  would  at- 
-*-  tract  any  young  woman  with  aspira- 
tions for  a  career  on  the  stage.  However, 
Miss  Greene  has  one  more  year  of  work 
to  gain  a  degree  at  the  New  York  State 
College  for  Teachers,  at  Albany.  She 
wants  that  degree  and  the  wider  back- 
ground which  education  will  give  her. 
She  declined  the  offer,  assured  that  she 
will  get  her  chance  when  she  is  ready. 

In  her  college  work,  Miss  Greene  is 
studying  modern  languages,  including 
French,  German  and  Italian.  Her  work 
also   includes   literature   and    the   history 


of  the  drama.  Each  week  she  nas  a  new 
part  to  study,  for  with  only  one  or  two 
exceptions  she  has  appeared  in  every 
play  produced  by  the  WGY  Players  in 
the  past  year.  Her  study  of  the  part 
does  not  mean  memorizing  the  lines,  for 
the  radio  player  may  read  his  lines.  She 
does,  however,  study  the  part  and  the 
play,  and  is  thus  enabled  to  give  an 
intelligent  interpretation  of  the  character 
she  is  ■playing. 

Hers  is  a  liquid  voice  of  such  distinctive 
tone  and  quality  that  it  can  always  be 
identified.  One  of  the  greatest  difficulties 
in  the  presentation  of  the  radio  drama 
is  the  selection  of  voices.  Each  voice 
must  be  distinctly  different  from  every 
(Turn  to  page  64) 


28 


RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doing 


Court  Hits  Radio  Corporation 


CJRadio  Corporation  is  Re- 
strained from  Selling 
Westinghouse 
Tubes 

IN  THE  February  issue  of  RADIO 
AGE  it  was  revealed  to  the  radio 
public  that  the  Radio  Corporation 
of  America,  in  replying  to  the  govern- 
ment's charge  that  the  corporation  was 
involved  in  a  trust  conspiracy,  made  the 
surprising  contention  that  the  Radio 
Corporation  had  been  pushing  its  radio 
activities  from   "patriotic"   motives. 

In  that  article  it  was  promised  that 
future  issues  of  this  magazine  would 
relate  some  of  the  judicial  proceedings 
in  which  the  Radio  Corporation  has 
become  involved.  It  was  suggested 
that  the  courts  would  not  be  found  hold- 
ing a  very  serious  view  of  the  patriotic 
professions  of  the  corporation. 

Almost  simultaneously  with  the  distri- 
bution of  the  issue  of  RADIO  AGE  con- 
taining these  facts  and  comments,  a 
federal  court  decision  in  Delaware  de- 
livered a  blow  to  the  Radio  Corporation 
which  must  have  rocked  that  organiza- 
tion like  a   Dempsey  right-hander. 

The  court  upheld  the  contention  of 
the  DeForest  Radio  Company  that  the 
Radio  Corporation  was  selling  tubes 
which  were  an  infringement  upon  the 
patents  owned  by  the  DeForest  people. 
The  Radio  Corporation  was  not  only 
restrained  from  further  sale  of  such 
tubes,  but  was  required  to  put  up  a  bond 
to  indemnify  the  DeForest  company  for 
damages   incurred   by   any   future   sales. 

Corporation's    Statement    Asked 

/^iX  THE  tenth  of  each  month  here- 
'--'  after,  the  Radio  Corporation  is 
required  to  file  a  verified  statement  with 
the  district  court  in  Wilmington,  Del., 
accounting  for  all  tubes  manufactured 
by  the  Westinghouse  Lamp  Company, 
whose  tubes  the  Corporation  had  been 
selling. 

Inasmuch  as  the  Radio  Corporation 
of  America  has  found  time  to  go  into 
the  United  States  Patent  Office  at  Wash- 
ington with  an  objection  to  the  registra- 
tion of  the  title,  RADIO  AGE,  under 
which  name  this  magazine  is  now  enter- 
ing its  fourth  year,  the  publishers  of 
RADIO  AGE  are  taking  more  than 
ordinary  interest  in  the  other  legal  ac- 
tivities  of  the   Corporation. 

The  Corporation  owns  and  controls 
"Wireless  Age"  and  complains  to  the 
Patent  Office  that  the  use  of  the  title, 
RADIO  AGE,  by  this  magazine  injures 
the  business  of  Wireless  Age,  the  cor- 
poration's organ.  Our  own  attorneys 
have  the  matter  in  hand  and  we  shall 
not  presume  to  forecast  the  result  except 
to  say  that  we  look  forward  to  a  long 
and  pleasant  Summer — and  cheaper 
tubes. 

Readers  of  RADIO  AGE  have  written 
hundreds  of  letters,  some  of  which  offer 


By  Frederick  A.  Smith 


Dr.  Lee  DeForest.  whose  company  scored 
its  initial  victory  against  the  Radio  Cor- 
poration of  America. 

to  contribute  to  a  fund  whereby  our 
defense  against  the  astonishing  con- 
clusions of  the  Radio  Corporation  may 
be  more  easily  financed.  Similar  offers 
have  come  from  manufacturers.  To  all 
these  we  have  replied  gratefully  that 
fortunately  we  do  not  need  financial 
assistance  in  fighting  the  S33, 000,000 
radio  gang.  All  we  ask  is  that  readers 
give  us  their  co-operation  by  continuing 
to  buy  our  magazine  and  that  manu- 
facturers show  their  approval  of  our 
stand  by  continuing  to  advertise  with 
us.  Not  even  the  Four  Horsemen  of  the 
Apocalypse  could  win  against  such  a 
combination    as    that. 

Must  Meet  Trust  Charge 

AS  THIS  April  issue  of  RADIO  AGE 
■**-  is  going  to  the  news-dealers  in  the 
United  States,  Canada,  Cuba,  England, 
Australia,  Mexico  and  various  other 
countries,  the  Radio  Corporation  is 
preparing  to  defend  itself  against  the 
charge   it   is   a   trust. 

Hearings  open  on  March  18,  in  New 
York,  before  the  Federal  Trade  Com- 
mission. Seven  other  corporations,  in 
addition  to  the  patriotic  leader  of  them 
all,  will  be  required  to  answer  the  govern- 
ment's accusation  that  thev  have  banded 
together  in  a  CONSPIRACY  TO  RE- 
STRAIN   TRADE. 

The  circulation  of  RADIO  AGE  has 
grown  so  large  that  it  is  necessary  for 
us  to  put  this  magazine  together  weeks 
in  advance  of  its  distribution  date.  It 
is  therefore  impossible  for  us  to  give 
results  of  the  New  York  proceedings 
in  this  issue.  We  shall  take  great  pleasure 
in  supplying  generous  information  in  a 
later  issue.     We  hope  you  will  read  the 


C Seven  Big  Corporations, 

Including  R.  O,  to 

Face  Charges 

March  18 

report  of  the  proceedings  as  published 
in  RADIO  AGE,  as  we  have  a  feeling 
that  our  report  is  going  to  be  a  bit  more 
complete  than  those  accounts  our  readers 
may   encounter  in   other  publications. 

Mr.  Sarnoff,  the  able  general  manager 
of  the  Corporation,  always  tells  the 
press,  when  asked  for  comment  on  the 
result  of  the  Corporation's  amazingly 
large  number  of  judicial  adventures, 
that  the  Corporation  "never  discusses 
its  affairs  in  the  public  prints." 

We  are  going  to  take  a  load  from  Mr. 
Sarnoff's  shoulders  and  discuss  them 
for  him.  While  we  shall  possibly  not 
be  as  sympathetic  in  our  treatment  of 
the  subject  as  Mr.  Sarnoff  would  be, 
we  assure  our  readers  we  shall  be  as  fair 
as  can  be  and  that  we  shall  not  be  so 
absurd  as  to  venture  an  untruth  that 
might  give  the  Corporation  cause  to 
grieve    over    our     moral    turpitude. 

The  Radio  Corporation  last  Summer 
wrote  us  a  letter  demanding  that  we 
give  up  the  name  of  our  magazine.  The 
Corporation's  communication  was  so 
arrogant  that  we  were  reminded  of  the 
famous  letlres  de  cachet  by  which  French 
despots  sent  honest  folk  to  the  Bastile. 

Truly,  we  have  nothing  but  respect 
for  the  Federal  Trade  Commission's 
courage  in  bearding  such  a  lion! 


Many  Features  Planned  for  May 
Radio  Age 

A  PROMISING  group  of  technical 
and  feature  articles  is  now  in  the 
process  of  preparation  for  the  May 
RADIO  AGE,  which  will  be  on  the 
news-stands  and  in  the  hands  of  sub- 
scribers by  the  15th  of  April. 

Among  the  technical  features  will  be 
an  article  on  a  practically  "squeal-less" 
regenerative  set  by  that  prominent 
experimenter,  Arthur  B.  McCullah.  Mc- 
Cullah  has  been  testing  this  set  for 
several  months. 

H.  Frank  Hopkins  has  perfected  a 
unit  that  any  fan  can  build,  and  which  is 
used  to  test  your  tubes  before  you  place 
them  in  the  set.  This  device  will  come 
in  handy  on  countless  occasions  and  will 
save  you  the  trouble  of  going  to  a  radio 
store  every  time  you  think  troubles  in 
your    set    are    caused    by    tubes. 

Frank  D.  Pearne  will  have  an  abso- 
lutely new  hookup,  incorporating  a  new 
circuit  he  has  developed. 

Paul  Green  will  be  on  hand  with  a 
hookup  almost  as  famous  as  his  "Baby 
Grand,"  while  Ray  G.  Piety,  inventor 
of  the  low-loss  3-circuit  tuner  in  the  Feb- 
ruary issue,  will  be  with  us  again. 

C.  H.  Dillon,  Edmund  H.  Eitel  and 
Brainard  Foote  are  others  who  are  plan- 
ning surprises.  And  as  usual  there  will 
be   the   blueprints  by  John  B.  Rathbun. 


RADIO  AGE  for  April,  1925 

Here  s  the 

IDEAL 

Announcer! 


What  the  Broadcasters  are  Doing 


29 


New 

York 

Radio 

Experts 

Set  Up 

Mythical 

Demi-God 

After  a 

Careful 

Research 


By 
S.  H. 

Hawkins 


Rate  of  Delivery 

Given  Prime 

Importance  in 

Tests  by  the 

Radio  Voice 

Technique 

Committee ; 

Quality 

of  Personality 

is  Left  to  the 

Individuals; 

Another 

Contest  to 

Decide  Who 

Resembles 

"Ideal" 


THE  ideal  radio  announcer  has  at 
last  been  described  and  classified. 
The  findings  of  the  Radio  Voice 
Technique  Committee  at  the  meeting 
held  in  February  in  the  studios  of  Sta- 
tion WJZ,  New  York  City,  have  created 
a  "demi-god"  at  whose  feet  the  fifteen 
hundred  or  more  members  of  the  new 
profession  of  radio  announcer  may  sit 
with  reverence  and  awe. 

Those  to  whom  the  creation  of  this 
perfect  being — the  Ideal  Radio  An- 
nouncer— may  be  attributed  include 
many  leading  figures  of  educational, 
scientific,  journalistic,  and  dramatic 
circles  in  New  York  City.  Their  de- 
cision, as  incorporated  in  the  Tabulated 
Report  of  the  Radio  Voice  Technique 
Committee,  is  as  truly  representative 
of  the  opinion  of  the  Great  American 
Public  as  could  be  desired. 

The  report,  based  upon  the  results  of 
research  conducted  by  Richard  C. 
Borden,  M.  A.,  Sc.  B.,  and  Alvin  C. 
Busse,  M.  A.,  co-directors  of  the  National 
Radio  Voice  Service,  bears  the  names  of 
Archibald  Bouton,  Ph.  D.,  Dean  of  the 
College  of  Arts  and  Pure  Sciences,  New 
York  University;  L.  E.  Bragdon,  Radio 
Editor,     New     York     Sun;      David     G. 


Casern,  Radio  Editor,  New  York  Tele-, 
gram  and  Evening  Mail;  Capt.  Stephen 
L.  Coles,  Radio  Editor,  New  York 
Herald-Tribune;  O.  E  Dunlap,  Jr., 
Radio  Editor,  New  York  Times;  Dr. 
Alfred  N.  Goldsmith,  Broadcast  En- 
gineer; Henry  C.  Hathaway,  Director 
of  Bureau  of  Radio  Broadcasting,  New 
York  University;  Reverend  A.  Edwin 
Kiegwin,  D.  D.,  of  the  -  West  End 
Presbyterian  Church;  James  E.  Lough, 
PH.  D.,  Pd.  D.,  Dean  of  the  Extramural 
Division,  New  York  University;  E. 
Wallace  McAdam,  M.  D.,  Dean,  New 
York  Homeopathic  Medical  College; 
Charles  B.  Popenoe,  Manager  of  Stations 
WJZ  and  WJY;  Stephen  Rathbun, 
Dramatic  Editor,  New  York  Sun;  Paul 
F.  Sifton,  Radio  Editor,  Sunday  World; 
and  H.  F.  Wooley,  Radio  Editor,  New 
York  American. 

His  Seven  Qualities 

'  1 1HE  necessary  characteristics  of  the 
J-  Ideal  Radio  Announcer  were  found  to 
be  seven  in  number,  and  the  nature  of 
each  was  determined  by  the  following 
seven  tests.  (1)  Average  Rate  Test; 
(2)  Rate  Variation  Test;  (3)  Average 
Pitch    Test;    (4)    Pitch    Variation    Test; 


(5)  Stress  Variation  Test;  (6)  Formality 
Test;  (7)  Distinctness  Test.  The  digest 
of  the  decisions  of  the  committee  mem- 
bers on  each  test  establishes  the  nature 
of  the  Ideal  Radio  Announcer. 
TThe  Ideal  Radio  Announcer  should 
speak  at  an  average  rate  of  approximately 
175  words  per  minute. 

The  Ideal  Radio  Announcer  should 
introduce  into  his  announcements  marked 
changes  in  rate  pace. 

The  Ideal  Radio  Announcer  should 
have  a  voice  of  low  middle  range. 

The  Ideal  Radio  Announcer  should 
introduce  into  his  announcements  marked 
pitch  variations  (avoidance  of  mono- 
tone). 

The  Ideal  Radio  Announcer  should 
introduce  into  his  announcements  marked 
stress  variations. 

The  Ideal  Radio  Announcer  should 
speak  in  a  formal,  but  friendly  manner, 
adapting  his  style  to  the  general  content 
of  the  program. 

The  ideal  Radio  Announcer  should 
speak  with  a  moderate  distinctness. 

The    committee's    decision    as    to   the 
relative  importance  of  the  various  char- 
acteristics of  the  ephemereal  announce- 
(Turn  to  page  52) 


30 


RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doing 


Guarding  the  Farmer's  Money 

How  Station  WLS  Does  It 

A  SQUARE 

DEAL  for  our 

FARMS 


CThe  attentive 
young  lady- 
speaking  into  the 
microphone  is  Mrs. 
Ellen  Rose  Dickey. 
'Home  Adviser" 
of  WLS'  Agriad- 
turai  Foundation 
who  gives  regular 
talks  from  the 
Sears-Roebuck  Sta- 
tion. In  the  circle  is 
Edgar  L.  Bill  Direc- 
tor-in-chief o/.  the 
station. 


WLS,  the  farmers'  station  at 
Chicago,  was  built  by  the  Sears- 
Roebuck  Agricultural  Foundation 
to  help  the  farmer  make  more  money. 
That  it  has  accomplished  its  purpose 
and  proved  its  value  in  terms  of  dollars 
and  cents  to  the  farmer  has  been  shown 
time  and  again  during  the  station's 
existence. 

Farmers  working  around  the  barn  lot 
in  Maine,  or  loading  their  hogs  for  market 
in  Missouri;  farmers  in  Georgia  and 
Oregon,  have  taken  tips  from  WLS 
and  saved  themselves  thousands  of 
dollars.  Farm  men  turn  to  their  radio 
station  for  aid  as  well  as  entertainment, 
for  WLS  is  the  only  strictly  agricul- 
tural broadcasting  station  in  the  world. 
The  most  valuable  service  given  from 
day  to  day  lies  in  the  market  reports 
which  are  broadcast  at  regular  intervals 
from  9  A.  M.  to  6  P.  M.  A  farmer  in 
Benton  County,  O.  A.  Koopman,  tells 
a  story  to  illustrate  the  practical  value  of 
these  daily  reports,  "I  went  to  my  son's 
farm  one  morning  last  fall  after  receiving 
the  nine  o'clock  report  from  WLS.  As 
I  got  there  my  son  and  the  hog  buyer 
stood  among  the  hogs,  and  the  butcher 
offered  hint  $10.60.  I  shook  my  head, 
and  then  the  buyer  offered  a  raise  if  we'd 
be  willing  to  take  the  drop.  We  took  him 
on.  I  went  home,  got  the  truck,  hauled 
them  four  miles,  unloaded,  but  the  buyer 
had   no    markets   yet.      Then    we   heard 


WTLS  say  20  cents  higher  and  he  then 
paid  my  son  §10.80  instead  of  $10.60." 
This  letter  from  Mr.  Koopman  is  typical 
of  thousands  of  letters  from  practical 
farmers  who  have  realized  financially  on 
their  station. 

Radio  Affects  Prices 

TV/TANY  farm-minded,  and  economic- 
-L'J-  minded  men  are  of  the  opinion  that 
WLS  is  helping  to  stabilize  market 
prices.  Large  numbers  of  stockmen 
living  within  a  200  mile  radius  of  Chicago 
formerly  shipped  their  cars  to  market 
without  a  knowledge  of  the  current  prices. 
Now,  however,  they  listen  in  on  the  11 
o'clock  market  reports  from  WLS,  and 
estimate  receipts  for  the  next  day  before 
they  load  their  cars.  If  the  market  looks 
good,  they  ship  their  stock,  but  if  it  in- 
dicates heavy  receipts,  they  cancel  their 


cars  and  await  a  more  favorable  time  for 
shipment. 

Henry  Stabler  of  Bureau  County, 
Illinois,  is  one  man  who  had  this  exper- 
ience. Last  December,  his  son  and  some 
neighbors  with  teams  were  hauling  hogs 
to  a  shipping  point.  Mr.  Stabler  hap- 
pened to  pass  the  Farmers'  Elevator 
office  and  noted  a  radio  message  on  the 
bulletin  board  which  stated  that  owing 
to  a  record  run  on  the  Chicago  market, 
the  prices  had  taken  a  sharp  drop  from 
those  of  the  preceding  day.  Mr.  Stabler 
immediately  got  in  touch  with  his  son  by 
telephone  and  the  wagons  with  the  hogs 
were  turned  home.  When  Mr.  Stabler 
sold  his  hogs  a  week  later,  they  brought 
a  dollar  a  hundred  more  than  he  would 
have  received  before.  He  estimates  that 
the  radio  report  saved  him  $175  on  this 
particular  deal. 

Most  farmers  urge  that  more  radio 
hours  be  spent  each  day  in  explaining 
Chicago    market    grades    and    prices. 

"We  are  interested  in  grain,  butter, 
eggs,  poultry,  hogs  and  cattle,"  writes 
O.  Gulbrandson  of  Kirley,  South  Dakota. 
Mr.  Gulbrandson  lives  50  miles  from  the 
railroad  and  fifteen  miles  from  a  tele- 
phone, and  the  WLS  Market  reports 
are  therefore  more  than  double  the  value 
for  him.  Lee  Mosher  of  De  Kalb  County, 
Illinois,  believes  that  the  radio  market 
reports  are  worth  more  than  $500  a  year 
to  him.  (Turn  to  page  56) 


RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doing  31 


Harry  Cooper 


The  Popular  Syncopating 

"WIZARD  of  WSB" 


By  RUSSELL  H.  HOPKINS 


A  TLA  NT  A:— Down  in  At-lan-ta, 
l\  Geor-gia,  where  the  folks  look 
-L  ■*-  upon  Radio  Station  WSB  with 
the  same  respect  accorded  cotton  and 
mint  juleps,  there  are  more  sleight-of- 
hand  musicians  than  in  any  other  part 
of  the  world,  including  Scandinavia. 
Up  in  Illinois  and  Xew  York  State,  the 
studio  directors  look  high  and  low  for 
talent  in  the  music  schools  and  song 
shops,  but  down  in  Atlanta,  one  of 
America's  pioneer  radio  broadcasting 
cities,  bookkeepers,  ex-newspapermen 
and  carpenters  are  usually  sought  when 
a  real  musical  genius  is  wanted.  Even 
printers  have  been  known  to  possess  an 
innate  ability  to  coax  music  out  of  any 
kind    of    instrument! 

Take  the  case  of  Harry  Cooper,  for 
instance.  Born  in  Atlanta,  his  remotest 
ambition  during  his  early  days  did  not 
approach  the  concert  stage.  He  worked 
at  everything  from  carpenter  and  printer 
to  journeyman  reporter,  finally  landing 
with  the  Atlanta  Journal,  which  owns 
and  operates  WSB. 

Discovered! 

AFTER    a   while    someone   discovered 
that   Harry  could    play   the    piano, 
"lust    a  side-line,"    he    explained   when 


questioned.  "Picked  it  up  when  I  was 
a  kid,  and  just  play  when  I'm  alone, 
anyway." 

Well,  his  newspaper  cohorts  asked 
him  to  play  something  when  the  man- 
aging editor  was  their  guest  at  a  tenth 
anniversary  banquet  in  his  honor.  That 
was  a  couple  of  years  ago,  and  Harry 
did  play  something!  In  fact,  he  played 
nearly  everything,  and  before  his  con- 
cert was  over  the  banqueteers  forgot 
there  was  ever  such  a  thing  as  a  manag- 
ing editor  or  that  he  had  announced  his 
tenth   anniversary   with   the   paper. 

Harry  was  immediately  signed  up, 
and  ever  since  he  has  been  playing  the 
piano  and  a  few  other  minor  instruments 
on  WSB's  regular  programs. 

Strange  to  say,  Cooper  doesn't  know 
the  difference  between  do  and  mi  in  the 
musical  scale,  but  neither  do  the  rest 
of  the  ex-newspapermen  or  printers  who 
are  winning  fame  with  their  musical 
prowess  throughout  America's  chain  of 
broadcasting  stations.  However,  this 
genius  has  an  extraordinary  creative 
ability  that  has  caused  nation-wide 
comment.  His  unique  conception  of 
popular    tunes    and    his    beautiful    and 


of  ten-times  weird  harmonies,  are  of  his 
own  composition  and  have  proved  im- 
mensely popular  because  of  their  or- 
iginality. 

The  "Mirthful  Pair" 
/^OOPER  is  not  only  an  accomplished 
^-^  musician,  but  an  actor  as  well. 
When  he  and  Announcer  Lambdin  Kay 
of  the  sonorous  voice  get  together  at  a 
public  broadcast  concert,  their  antics 
are  a  source  of  unalloyed  mirth  and 
interest  to  the  onlookers  as  well  as  the 
listeners. 

For  who  is  not  familiar  with  Kay's 
"At — -Ian — ta,  Geor — gia,"  andhisrhyth- 
mic  sing-song  voice,  which  has  made 
him  truly  one  of  the  few  distinctive  an- 
nouncers in  the  country?  And  it  was 
Lambdin  Kay  who  "discovered"  Cooper 
and  induced  him  to  leave  the  anonymity 
of  newspaperdom  for  the  fame  of  success- 
ful   broadcasting. 

Other  stations  have  their  "Kings  of 
the  Ivories,"  "Czars  of  Jazz"  and 
"Piano  Ticklers,"  but  WSB  has  its 
"Syncopating  Wizard"  and  is  justly 
proud  of  him  despite  the  fact  that  a  sheet 
of  music  is  about  twice  as  hard  for  him 
to  read  as  an  essay  in  the  original  Greek. 


32 


RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doing 


News  Waves  from  the  Domain  of  Radio 


How  Isham  Jones  Regards  Radio 
By  A.  C.  E.  Schonemann 


T 


HE  trite  old  phrase,  "Familiarity 
breeds  contempt"  probably  is  the 
most  effective  expression  that  one 


fans  from  two  Chicago  stations — KYW 
and  WLS.  His  orchestra  is  one  of  the 
best  known  phonograph  recording  units 


could  use  in  epitomizing  the  attitude  of     in  the  United  States,  and  in  the  art  of 


Isham     Jones 
the    matter    of 
broadcasting    jazz 
melodies    via    the 
ether  route. 

Jones  is  not  un- 
mindful of  the 
advantages  offered 
by  radio.  In  four 
years  he  and  his 
orchestra  have 
become  firmly  in- 
trenched in  the 
good  graces  and 
affections  of  the 
great  army  of 
dance  fans  that 
frequent  the  Col- 
lege Inn  at  the 
Hotel  Sherman  in 
Chicago.  The  last 
six  months  have 
brought  a  new 
triumph  to  Isham 
Jones,  and  with 
it  hascome  a 
mighty  audience 
— invisible — but 

enthusiastic  and  appreciative  to  the  'nth 
degree  and  drawn  from  all  classes  of 
society — men,  women  and  children — 
from  all  walks  of  life  and  out  into  every 
highway  and  by-way. 

"No  one  can  doubt  or  question  the 
influence  of  radio,"  said  Jones,  pulling 
out  a  sheaf  of  letters  from  radio  fans. 
"Here  is  the  answer,  and  with  it  comes 
proof  that  destroys  any  uncertainty  that 
one  may  have  if  he  regards  radio  as  a  fad 
or  passing  fancy.  However,  radio  has 
come  so  suddenly  and  grown  so  rapidly 
that  nobody  seems  to  know  how  to 
handle  it  so  it  will  serve  everybody  alike. 

"The  public  ear  is  sensitive  and  when 
our  jazz  music  becomes  a  part  of  a  varied 
program  it  gains  in  popularity,"  con- 
tinued Jones. 

"However,  the  minute  we  make  our 
music  commonplace,  we  destroy  its  ef- 
fectiveness; it  must  not  be  over-played, 
but  served  with  discrimination  and  not 
to  the  point  where  it  occupies  the  spot- 
light throughout  the  entire  program. 

Good  Advertising 

T^HERE  are  few  if  any  people  who  en- 
-*-  tertain  who  will  question  the  advan- 
tages of  broadcasting.  The  advertising 
obtained  in  this  manner  is  invaluable  to 
an  orchestra;  it  sells  phonograph  records, 
it  popularizes  song  hits  and  it  helps  the 
hotel  or  institution  that  is  guaranteeing 
the  finances  of  the  various  studios;  but 
when  we  play  jazz  without  any  limita- 
tions and  allow  it  to  monopolize  the  air, 
then  radio  injures  rather  than  helps  the 
cause  of  popular  music." 

Isham    Jones    has    entertained    radio 


(Mabel  SykeB  Photo) 

Isham  Jones 


concocting  jazz 
melodies  of  the 
foot-teasing  type, 
Isham  Jones  has 
to  his  credit  a  half 
dozen  or  more  of 
the  best  known 
and  most  popular 
hits  turned  out  in 
1924.  Consider 
"Swingin'  Down 
the  Lane,"  "The 
One  I  L  o  v  e," 
"Spain,"  "Never 
Again,"  and  "At 
the  End  of  a  Wind- 
ing  Lane." 

"A  radio  audi- 
ence is  just  as  re- 
sponsive as  the 
nightly  crowds 
that  fill  a  ballroom 
or  cabaret,"  said 
Jones.  "The  dif- 
ference is  that 
radio  fans  express 
their  appreciation 
by  letters  and  the 
others  show  their  interest  by  applause. 
In  either  case  it  is  not  a  difficult  matter 
to  boost  a  song.  The  unfortunate  part 
of  'plugging'  a  song  is  that  many  radio 
artists  overplay  the  number  by  singing 
it  continually. 

"When  we  began  broadcasting,  the 
sales  of  phonograph  records  dropped  off. 
We  attributed  this  to  the  fact  that  we 
broadcast  off  and  on  for  long  periods 
from  the  College  Inn  and  that  the  pros- 
pective purchasers  of  phonograph  records 
had  only  to  turn  the  radio  dials  to  pick 
up  the  orchestra,  so  they  were  not  inter- 
ested in  buying  records. 

"Now  we  broadcast  from  the  studio  in 
the  Hotel  Sherman.  Our  programs  are 
given  on  Wednesday,  Thursday,  Friday 
and  Saturday  evenings,  and  they  extend 
over  two  periods  of  about  twenty 
minutes  each.  We  play  about  five  num- 
bers and  in  presenting  them,  we  consider 
the  matter  of  variety  just  as  important 
as  an  effective  and  appealing  rendition 
of  each  selection.  Above  all,  we  do  not 
try  to  overdo  our  part  of  the  entertain- 
ment. 

Arrangement  is  Vital 

'  I  ''HE  arrangement  of  an  orchestra  in 
J-  the  studio  is  in  many  respects  similar 
to  the  plan  used  in  making  phonograph 
records.  The  violins  are  placed  within 
a  few  feet  of  the  microphone;  the  saxo- 
phones six  or  eight  feet;  the  brass  instru- 
ments fifteen  feet  and  the  drums  are 
eliminated  entirely.  It  is  necessary  that 
the  orchestra  play  softly,  and  care  must 
be  used  so  that  a  group  of  instruments 
(Turn  to  page  70) 


Station  WJJD  Opens  a 
Chicago  Studio 

ID  Y  arrangement  with  the  Garod  Cor- 
-'-'  poration,  the  Loyal  Order  of  Moose 
announces  the  completion  of  extensive 
preparations  for  maintaining  a  Chicago 
studio  in  the  Palmer  House,  to  be  known 
as  the  Garod  Studio  of  Radio  Station 
WJJD. 

Although  the  task  of  erecting  thirty- 
seven  miles  of  specially  constructed 
poles,  the  building  of  cross-arms,  the 
stringing  of  over  one  hundred  and 
fifty  miles  of  broadcasting  wires  and 
telephone  cables,  connecting  the  new 
studio  with  the  Mooseheart  station  has 
been  completed  by  the  Western  Union 
organization,  actual  broadcasting  did 
not  begin  until  Monday,  March  9th. 
Elaborate  preparations  were  made  to 
celebrate  the  formal  opening  with  a  pro- 
gram of  unusual  entertainment  which 
was  unique  in  the  annals  of  radio  broad- 
casting. 

The  event  was  signalized  by  a  banquet 
in  the  Victorian  room  of  the  Palmer 
House  on  the  night  of  the  opening  which 
was  attended  by  about  one  hundred  per- 
sonages prominent  in  civic,  theatre  and 
radio  circles.  Jack  Nelson,  managing 
director  and  announcer,  officiated  as 
master  of  ceremonies. 

Mr.  Nelson  had  the  unique  pleasure,  on 
that  occasion,  of  introducing  and  pre- 
senting all  of  his  distinguished  contem- 
poraries in  Chicago.  It  was  Mr.  Nelson's 
opinion  that  seldom  if  ever  before  have 
there  been  assembled  so  varied  and  re- 
nowned an  aggregation  of  radio  lumi- 
naries under  one  roof  to  be  heard  through 
the    same    microphone    on    one    evening. 

The  following  directors  and  announc- 
ers, and  their  talented  proteges,  attend- 
ed: Charles  E.  Ebstein,  owner-director 
of  WTAS;  Bob  Boniel,  "The  Voice  of 
the  Great  Lakes,"  i.  e.,  WEBH;  George 
Hay,  the  solemn  old  judge  of  WLS; 
Wilson  J.  Wetherby  of  KYW;  Jerry 
Sullivan  of  WQJ,  "Chi-CAW-go;"  Chas. 
Gabriel  and  Quin  Ryan,  the  famous 
WGN  team,  and  last  but  not  least,  Miss 
Judith  Waller  of  WMAQ. 

In  addition  to  the  radio  stars  who 
accepted  invitations,  Secretary  of  Labor 
James  J.  Davis  attended,  and  many  of 
Chicago's  prominent  men  participated  in 
WJJD'S  "open  house." 

Among  those  present  were:  Mayor 
William  E.  Dever  and  his  official  family, 
Mr.  Potter  Palmer,  and  the  leading 
representatives  of  the  opera  and  the 
theater  who  were  in  Chicago  on  Monday, 
March  9th. 

Arrangements  were  made  to  film  the 
colorful  event  and  to  photograph  the 
artists  and  other  guests  of  WJJD  for  the 
news-reels.  Similar  arrangements  were 
made  to  take  motion  pictures  of  Charlie 
Straight's  Orchestra  at  the  Rendezvous, 
together  with  their  entertainers,  all  of 
which  were  broadcast  through  WJJD 
by  direct  wire. 

This  gala  program  inaugurated  the 
regular  broadcasting  of  nightly  programs. 


RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doing  33 


(Drake  Photo) 

Glenn  Rowell,  musical  director  of  Sta- 
tion WLS  and  an  entertainer  on  RADIO 
AGE  programs  from  the  Sears-Roebuck 
Station. 

GATHER  around,  folks,  and  we'll 
tell  you  about  the  wonderful  new 
additions  which  have  been  made 
to  the  official  RADIO  AGE  family  of 
broadcasters  during  the  past  month. 

Of  course,  you're  already  familiar  with 
such  stars  as  Banks  Kennedy,  Art  Linick, 
Axel  Christensen,  Nate  Colwell,  the 
Dennis  Sisters,  Loos  Brothers  and  others 
who  appear  on  exclusive  RADIO  AGE 
programs  from  KYW  and  WEBH  each 
month.  Their  reputations  have  been 
assured,  so  we  just  mention  them  to  let 
you  know  they're  still  on  the  map  and 
going  strong. 

Not  to  stand  still,  however,  RADIO 
AGE  decided  to  augment  its  staff  of 
artists,  and  accordingly  search  was  made 
throughout  the  Chicago  broadcasting 
fraternity  for  some  more  "stars"  who 
would  twinkle  under  the  RADIO  AGE 
banner,  which  is  now  known  from  coast 
to  coast  for  the  excellence  and  variety 
of  its  programs. 

You   Know  "Little   Glenn" 

WELL,  we  can't  keep  the  secret  any 
longer,  so  here  are  the  latest  sur- 
prises. To  begin  with,  none  other  than 
Glenn  Rowell,  musical  director  of  Sta- 
tion WLS,  the  Sears- Roebuck  Station  at 
Chicago,  has  been  obtained  to  appear  on 
RADIO  AGE  programs  from  WLS. 
The  first  program  was  Friday,  March  6, 
when  Glenn,  with  his  side- kick,  Ford 
Rush,  started  off  RADIO  AGE's  hour  of 
broadcasting  with  their  "Lullaby  Time." 
Ford  and  Glenn  appeared  intermittently 
during  this  program  under  the  auspices 
of   this   magazine. 

On  the  same  program  RADIO  AGE 
"sprung"  two  more  surprises  that  are 
destined  to  prove  agreeable  to  the  army 
of  reader-listeners  possessed  by  the 
Magazine  of  the  Hour.  The  first  was 
Miss  Grace  Wilson,  noted  contralto  of 
nation-wide  vaudeville  fame.  She  has  a 
deep  contralto  voice  that  is  almost 
masculine,  and  yet  it  has  the  tenderness 


T^ADIO  Age  Adds  Several  Noted 
*A     Stars  to  Its  "Studio  Staff" 

Some  ADDITIONS 
to  Our  FAMILY 

Listen  In  and  Get  Acquainted 


radio  stations  this  Spring.  They  were 
persuaded  to  start  their  career  over 
Chicago  stations  under  the  direction  of 
RADIO  AGE,  and  they  made  their  debut 
from  WLS  on  the  March  6  program. 

The  next  evening,  March  7,  from  mid- 
night to  the  wee,  sma'  hours,  they  again 
appeared  on  a  RADIO  AGE  program 
from  KYW,  on  our  monthly  Jazz  Car- 
nival from  the  Little  Red  Studio  on  the 
Congress  Hotel.  All  listeners  pro- 
nounced their  singing  of  popular  and 
southern  melodies  as  the  "best  yet"  for 
a  girls'  group.  Their  voices  are  evenly 
matched,  and  in  addition  three  of  the 
girls  strum  ukeleles  and  banjos  while 
they  sing,  thus  adding  a  quaint  touch  to 
their  selections. 

And  More  Surprises! 

THE  members  of  the  quartet  are,  be- 
sides Miss  Mildred  Zoller — Florine 
Redenbo,  soprano;  Mary  Gallagher,  alto; 
and  Pauline  Zoller,  second  soprano. 

Another  important  announcement  con- 
cerns A.  W.  "Sen"  Kaney,  KYWs  first 
announcer  a  few  years  ago,  who  has 
returned  to  the  fold  after  announcing  at 
WJAZ,  WEBH  and  WGN,  all  of  Chicago. 
(Turn  to  page  57) 


The  circle  above  shows  Miss  Mildred 
Zoller,  director  of  the  Mt.  Morris  College 
Girls'  Quartet,  which  appeared  over  WLS 
and  KYW  on  RADIO  AGE  programs 
this  month.  Below  is  Lee  Sims,  nationally 
known  pianist  and  entertainer,  who  may 
be  heard  on  RADIO  AGE's  KYW  pro- 
grams the  first  Saturday  in  every  month 
beginning  at  midnight. 

of  a  woman's  vocal  expression.  Miss 
Wilson  has  been  termed  the  "Girl  with 
the  perfect  radio  voice."  She  sang  several 
popular  and  character  songs  for  RADIO 
AGE  on  this  first  WLS  program.  She 
will  appear  on  many  future  programs  for 
this    magazine. 

The  biggest  surprise  next  to  be  un- 
corked was  the  Mount  Morris,  (111.) 
College  Girls'  Quartet,  under  the  direc- 
tion'of  Miss  Mildred  Zoller,  a  senior  at 
the  College.  These  girls  have  appeared 
consistently  from  WOC  at  Davenport, 
la.,  and  plan  a  tour  of  Middle  Western 


W 

United  Pboto,(N.Y. 

Miss  Grace  Wilson,  contralto,  who  sang 
for  RADIO  AGE  from  WLS  Friday, 
March  6.  She  is  an  experienced  vaudeville 
singer  and  has  a  big  following  among 
radio  fans. 


34  RADIO  AGE  for  April,  1925 


What  the  Broadcasters  are  Doin* 


:■■:-"    ■■:      ■-    ...,:, 


£  if  V.   ! 


Daguerre  Photo 


A  FAVORITE  AMONG  THOUSANDS 

Such  a  reputation  is  enjoyed  by  Belle  Forbes  Cutter,  who  has  won 
friends  from  several  radio  stations  in  the  Middle  West.  Her  radio 
"home"  seems  to  be  the  studio  at  WEBH,  where  she  began  her  radio 
career.  Miss  Cutter  has  one  great  accomplishment  to  her  credit; 
that  of  providing  entire  programs  at  radio  stations.  That's  quite 
a  bit  of  work  for  one  soprano  to  achieve  in  one  evening,  but  to  Miss 
Cutter  it's  a  part  of  her  regular  routine. 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


More  Volume  and  Range  with 

A  5-Tube  Radio  Frequency  Set 

By  JOHN  B.  RATHBUN 


SINCE  the  introduction  of  the  five- 
tube  neutrodyne  about  two  years 
ago,  we  have  had  an  almost  end- 
less stream  of  five-tube  radio  frequency 
"dynes"  which  testify  to  the  popularity 
of  this  sort  of  radio  receiver.  This 
neutrodyne  was  the  first  really  high 
powered  type  introduced  to  the  general 
public  for  broadcast  reception.  The 
fans  to  this  time  had  been  limited  to  the 
three-tube  regenerative  with  the  con- 
ventional detector  and  two  stages  of 
audio  frequency.  The  addition  of  the 
two  stages  of  radio  frequency  to  the 
detector  in  the  neutrodyne  not  only- 
increased  the  range  enormously,  but  also 
very  considerably  added  to  the  selectiv- 
ity, and  I  believe  that  the  selective 
feature  of  the  tuned  radio  frequency 
set  had  as  much  to  do  with  its  promotion 
as  the  increased  range  and  the  possi- 
bility of  coast-to-coast  reception  on  the 
loud  speaker. 

Untuned  radio  frequency  reception 
with  untuned  radio  frequency  coupling 
units  had  proved  somewhat  of  a  fizzle, 
not  only  because  the  maximum  range 
and  signal  strength  were  not  developed 
but  also  for  the  reason  that  such  re- 
ceivers were  hardly  more  selective  than 
the  regenerative  set  of  that  period,  and 
even  two  years  ago  the  question  of  inter- 
ference was  becoming  a  serious  proposi- 
tion. By  tuning  the  transformers  be- 
tween the  radio  frequency  stages,  we 
reach  the  amplification  peak  in  each 
stage  and  also  increase  the  losses  at  a 
number  of  points  so  that  undesired 
stations  could  be  eliminated  with  cer- 
tainty, even  through  strong  local  inter- 
ference. Using  three  tuning  controls 
made  long  distance  reception  possible 
for  the  city  dweller  on  every  night  in 
the  week. 

The  Typical  5-Tube  Set 
TTSUALLY   the   five-tube   outfits   con- 
^    sisted    of   two    stages   of  .radio    fre- 
quency amplification,  detector,  and  two 

Blueprints  of  the  Five- 


Copyright:    1925 


A  Receiver  that  Will 
Minimize  Distortion 


stages  of  transformer  coupled  audio 
stages.  There  was  seldom  any  attempt 
at  regeneration  in  the  detector  tube 
circuit  or  any  other  means  of  amplifica- 
tion outside  of  the  simple  amplifying 
powers  of  the  tubes  themselves.  True, 
the  first  neutrodyne  introduced  by 
Prof.  Hazeltine  was  of  the  reflex  type, 
but  strange  to  say,  little  interest  was 
taken  in  the  reflexed  neutrodyne  until 
a  few  months  ago.  Experimenters  seemed 
content  to  stick  to  straight  radio  fre- 
quency amplification  without  the  assist- 
ance   of    either    regeneration    or    reflexed 


WHAT  KIND  OF  A  SET  DO 
YOU  WANT? 

The  RADIO  AGE  ANNUAL 
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R.  F.  or  audio  amplification.  In  the  most 
part  they  confined  their  inventiveness  to 
contriving  schemes  for  the  elimination  of 
oscillations  in  the  radio  frequency  stages. 

For  a  long  time  the  suppression  of 
oscillations  in  the  radio  frequency  stages 
was  a  problem  to  which  many  solutions 
have  since  been  offered.  We  have  the 
well-known  neutralizing  system  intro- 
duced by  Prof.  Hazeltine,  the  reversed 
feed-back  system,  the  potentiometer, 
and  similar  devices,  and  it  is  in  this  part 
of  the  circuit  that  most  five  tube  radio 
frequency  circuits  differ  from  each  other. 
It  would  be  almost  impossible  to  say 
which  of  these  systems  has  proved  the 
most  sensitive  and  efficient,  for  each 
type  has  its  band  of  adherents  who  defy 
any  of  their  opponents  to  show  better 
reception  or  greater  range. 

It  has  long  been  the  belief  of  the 
writer  that  very  marked  improvement 
could  be  made  in  the  five  tube  radio 
frequency  receivers  by  the  introduction 
of  regeneration  in  the  detector  circuit 
or  by  reflexing  certain  of  the  stages  so 
that  some  of  the  tubes  could  be  made  to 
perform  dual  duty.  Shortly  after  the 
introduction  of  the  neutrodyne,  I  made 
several  experiments  in  obtaining  re- 
generation in  the  detector  circuit  by 
means  of  a  variometer  or  tuned  im- 
pedance in  the  plate  circuit,  but  while 
this  increased  the  range  and  signal 
strength  considerably,  it  did  not  meet 
favor  for  the  reason  that  it  introduced 
a  fourth  control,  and  a  rather  critical 
sensitive  control  at  that.  Further, 
regeneration  was  not  always  dependable 
with  neutralized  grids,  and  as  neu- 
tralization held  the  floor  at  that  time  to 
the  exclusion  of  every  other  idea,  the 
matter  was  dropped  for  the  time  being. 

Rheostats  Cause  Trouble 

npO    ELIMINATE    the    fourth    regen- 
*■  erative   control,    I    next    tried    several 


(Turn  to  page  38) 
Tube  Radio  Frequency  Receiver  on  Two  Pages  Following. 


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38 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Results  with  a  Reflexed  Detector 


(Continued  from  page  35) 
regenerative  stunts  in  the  detector  cir- 
cuit such  as  the  fixed  tickler  used  in  the 
Wizard  receiver,  and  the  Ultra-audion 
single  control  method,  both  of  which 
gave  strong  regeneration  and  sensi- 
tivity but  which  made  the  rheostat 
controls  critical  and  difficult  to  manage. 
With  such  circuits,  control  of  the  regen- 
eration is  had  entirely  by  the  rheostatic 
or  filament  emission  method,  and  a 
vernier  rheostat  is  absolutely  essential 
for  the  proper  adjustment.  Unless  it 
was  brought  just  below  the  oscillating 
point,  the  circuit  would  break  out  into 
violent  free  oscillation  with  accom- 
panying howls  and  shrieks.  While  this 
gave  wonderful  results  in  the  hands  of 
an  experienced  operator,  it  certainly 
was  not  a  circuit  to  install  in  the  home 
or  for  the  everyday   broadcast   listener. 

It  seemed  for  a  while  that  the  only 
resort  was  to  reflex  the  detector  circuit 
and  this  is  what  I  finally  accomplished 
after  a  number  of  experiments.  The 
reflexing  of  the  so-called  detector  stage 
or  third  tube  both  increased  the  volume 
and  improved  the  quality  of  the  recep- 
tion, and  from  many  standpoints  was 
an  advance  over  the  regenerative  prin- 
ciple or  the  totally  reflexed  method  by 
which  all  of  the  tubes  were  reflexed. 
Reflexing  the  third  tube  alone  gave  us 
approximately  three  stages  of  radio 
frequency  amplification  with  the  same 
number  of  tubes  ordinarily  used  to  obtain 
two  stages,  and  in  addition  it  added 
about  0.8  of  an  audio  stage.  Further 
audio  amplification  was  then  obtained 
by  two  stages  of  resistance  coupled 
audio,  which  gave  the  total  audio  volume 
without  the  distortion  usually  intro- 
duced by  iron  core  radio  frequency 
transformers. 

Summing  up  the  matter,  we  obtain 
practically  three  stages  of  radio  fre- 
quency amplification  and  the  equivalent 
of  two  audio  frequency  transformer 
coupled  stages  by  five  tubes,  and  with- 
out distortion  or  "razzing"  even  when 
the  tubes  are  being  pushed  to  the  limit. 
The  audio  stages  consist  of  one  trans- 
former coupled  stage  and  two  resistance 
coupled  stages,  which  give  us  a  volume 
slightly  better  than  two  transformer 
stages.  A  crystal  detector  performs  the 
rectification  without  introducing  the 
tube  noises  that  ordinarily  affect  the 
output.  In  short,  it  is  just  like  adding 
two  stages  of  radio  amplification  to  a 
single  reflex  circuit  and  then  increasing 
the  volume  by  the  further  application 
of  two  resistance  coupled  stages. 

The  Circuit  Layout 

TN  FIG.  1  we  have  the  layout  shown 
^  by  a  schematic  diagram  and  in  Fig. 
2  the  same  circuit  is  given  in  "picture" 
form,  which  not  only  shows  the  wiring 
in  simplified  form,  but  also  suggests 
the  arrangement  of  the  apparatus  behind 
the  panel.  Fig.  3  is  the  front  elevation 
of  the  panel  with  the  control  dials  and 
1  nobs  located. 

Looking  at  Fig.  1  or  Fig.  2  we  see  the 


usual  first  two  radio  frequency  tuoes 
(Tl)  and  (T2),  and  the  three  radio 
frequency  coils  or  transformers,  (RFT-1), 
(RFT-2)  and  (RFT-3)  connected  up  in 
the  usual  way  of  radio  frequency  trans- 
formers. The  transformers  are  tuned 
by  the  17  plate  (0.0003S  mf)  variable 
condensers  (CI),  (C2)  and  (C3)  con- 
nected across  the  secondary  coils  of  the 
transformers.  There  is  little  to  say 
about  the  transformers  except  that  they 
are    of    the    conventional    type    used    in 


BILL 

OF  MATERIALS 

FOR  THE  SET 

MARK  NC 

.  OF 

(LETTER) 

PIECES     NAME  OF  ITEMS      SIZE 

A 

1 

Filament   "A"   Battery,  Stor- 
age   type 6    Volt* 

AT 

1 

Audio      Frequency     Trans- 
former  6-1    Ratio 

B 

2 

45    Volt    Block,    of    MB" 

Battery         Large. 

C1-C2-C3 

.      3 

Variable       Condensers 

O.OOOoS    mf     (17    Pit.) 

CD 

1 

Fixed  Crystal  Detector 

•GL1-GL2 

2 

Grid  Leaks 1-2  Megohms 

Jl 

1 

Two  circ:t*t  Jack Standard 

J2 

1 

Single    Circuit    Jack      Standard 

Kl 

1 

Fixed  Mica  Condenser  0.006  Mf. 

K2 

1 

Fixed  Mic*  Condenser  0.002  Mf. 

K3 

1 

Fixed  Mica  Condenser  0.002  Mf. 

•K4 

1 

Fixed  Mica  Condenser  0.006  Mf . 

•K5 

1 

Fixed  Mica  Condenser  0.006  Mf. 

K6 

1 

Fixed  Mica  Condenser  0.002  Mf. 

K7 

1 

Fixed  Mica  Condenser  0.500  Mf. 

•N1-N2    .. 

.      2 

Resistors      or      Coupling 

Resistances 50,000      Ohms 

PO 

1 

Potentiometer 

400  ohms,  or  200  ohms 

R1-R2 

2 

Rheostats       for       filament 

Control 6       Ohms 

RFT-1-2- 

J.   3 

Radio      Frequency      Trans- 
formers,    (Tuned)     .Standard 

RFX 

1 

Untuned      Radio      Frequency 
Transformer    .200-600   meters 

SW 

1 

Battery     Switch Standard 

s 

S 

Tube        Sockets Standard 

TI-2-3-4-5     5 

201A  Amplifier  Tubes  Standard 

VM 

1 

Battery       Voltmeter        (Flush 
Typei 8     to     10     Volts 

W 

1 

Panel 7"x26"x3-I6" 

Marked. 

6 

Binding    Posts Standard 

X 

1 

Terminal  Strip  (bake- 

Y 

1 

Bottom       Board       (Wood) 

Z 

30' 

Radio  Cabinet 7"x26* 

Tinned     Copper     Square     Bus 

Wire      No.    14 

6' 

Spaghetti       Standard 

50 

Solder      Lugs Standard, 

D 

.     3 

Dials    and    Knobs    4"    Diameter 

NOTEI 

Items  marked  (*'  can  be  substituted 

for     by     c< 

mpl 

ete     resistance     coupling     units. 

standard  radio  frequency  circuits,  and 
that  it  is  far  more  desirable  to  purchase 
these  parts  than  to  attempt  making 
them  at  home. 

The  three  tubes  (T1-T2-T3)  are  con- 
trolled by  the  six  ohm  rheostat  (Rl) 
while  the  two  audio  frequency  ampli- 
fying tubes  (T4)  and  (T5)  are  regulated 
by  the  six  ohm  rheostat  (R2).  In  giving 
the  resistance  of  these  rheostats,  I  am 
assuming  that  201A  tubes  are  used, 
because  they  give  better  results  than  the 
dry  cell  type.  If  199  tubes  are  used, 
then  the  resistance  of  the  rheostats 
must  be  higher,  say  15  or  20  ohms. 
With  five  tubes,  dry  cell  operation  is 
not  recommended,  for  in  the  end  it  will 
be  far  more  expensive  to  replace  dry 
cells  than  to  purchase  a  storage  battery 
and  recharge  it  from  time  to  time.  Dry 
cell  tubes  do  not  give  the  amplification 
of  the  storage  battery  201A  type. 

Grid  potentials  are  regulated  by  the 
potentiometer  (P9).  While  there  are 
certain  objections  which  can  be  leveled 
at  this  type  of  control,  yet  it  is  the  better 
method  for  the  beginner,  especially 
when  it  is  not  known  what  make  or  type 


of  apparatus  he  intends  to  use.  A  400 
ohm  potentiometer  is  the  best,  but  a  200 
ohm  can  also  be  used,  and  to  reduce  the 
radio  frequency  resistance  in  the  grid 
return  line,  a  fixed  bypass  condenser 
(Kl)  of  0.0006  mf  capacity  is  con- 
nected between  the  slider  and  the  nega- 
tive "A"  post  of  the  potentiometer 
resistance  coil.  The  impedance  of  a  wire 
wound  potentiometer  is  considerable, 
and  unless  the  bypass  condenser  is 
installed,  the  tuning  will  be  upset  at 
every  adjustment  of  (PO). 

Reflexed  Third  Tube 

'"TUBE  (T3)  is  the  tube  ordinarily 
•*-  used  as  the  detector  tube,  but  in  this 
case  it  is  the  tube  of  a  special  reflex 
circuit,  acting  both  as  a  radio  and  audio 
amplifier  at  one  time.  In  fact,  there  is 
no  detector  tube  in  the  circuit  since  the 
major  part  of  the  rectification  is  per- 
formed by  the  crystal  detector  (CD). 
Transformer  (RFT-3)  connects  the  radio 
stages  to  the  reflex  stage  and  the  reflex 
is  tuned  by  the  third  variable  condenser 
(C3).  Note  that  all  of  the  radio  fre- 
quency and  audio  frequency  trans- 
formers are  marked  according  to  the 
connection  posts  as  at  (P),  (  +  B),  (G) 
and  — F),  to  correspond  with  the  mark- 
ings on  the  actual  coils. 

At  (RFX)  is  an  untuned  radio  fre- 
quency transformer  used  for  coupling 
the  plate  circuit  of  (T3)  with  the  crystal 
detector  and  the  audio  transformer 
(AT).  The  latter  is  of  the  usual  iron 
core  type,  bypassed  on  both  the  primary 
and  secondary  sides  by  the  fixed  bypass 
condensers  (K2)  and  (K3).  Ordinarily 
the  capacity  of  these  condensers  is 
0.0015  mf  to  0.002  mf,  but  much  depends 
upon  the  type  of  audio  transformer 
used.  In  some  cases  it  will  be  found 
advisable  to  omit  (K3)  altogether  when 
there  is  much  distributed  capacity  in 
the  primary  winding. 

On  carefully  examining  the  circuit 
of  tube  (T3)  you  will  see  that  it  is  a 
simple  single  tube  reflex  circuit  giving 
the  equivalent  of  one  stage  of  Fadio 
and  one  stage  of  audio  amplification, 
so  that  up  to  and  including  (T3)  we 
have  three  radio  and  one  audio  stage  on 
three  tubes.  This  alone  will  give  good 
results,  but  for  the  proper  loud  speaker 
volume  under  all  ordinary  conditions, 
it  was  considered  advisable  to  add  the 
two  resistance  coupled  stages  as  shown 
by  tubes  (T4)  and  (T5). 

By  plugging  in  at  jack  (Jl)  we  obtain 
the  output  of  three  radio  and  one  audio 
stage.  By  plugging  in  at  the  jack  (J2) 
we  obtain  three  radio  '  and  about  2.6 
audio  stages. 

A  typical  resistance  audio  coupling 
is  made  for  the  tubes  (T4)  and  (T5). 
The  fixed  condensers  (K4)  and  (K5) 
of  0.006  mf  capacity  are  the  coupling 
devices  in  the  grid  lines,  while  the  re- 
sistors (Nl)  and  (N2)  are  non-inductive 
resistances  of  from  48,000  to  50,000 
ohms.  Both  of  the  resistors  are  con- 
nected between  the  positive  "B"  (  +  B) 
and  the  plate  (P)  of  the  tube,  and  it  is 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


39 


Tubes  Do  Dual  Duty  in  This  Set 


the  difference  of  potential  established 
across  these  resistors  that  causes  the 
amplification.  The  grid  leaks  (GL1) 
and  (GL2)  are  of  one  megohm  to  two 
megohms  capacity  and  are  connected 
between  the  grids  and  ( — A)  just  as 
with  any  grid  leak.  Such  resistors 
introduce  no  distortion  into  the  circuit, 
and  when  worked  in  connection  with 
one  transformer  coupled  stage  as  at 
(AT),  we  obtain  both  volume  and  purity 
of  tone.  The  ratio  of  (AT)  should  be 
from  i  to  i  but  no  higher. 

The  resistors  (N1-N2)  can  be  obtained 
from  a  number  of  RADIO  AGE  adver- 
tisers, either  as  separate  units  or  as 
assembled  units  containing  the  fixed 
condensers,  resistor  and  leaks  all  in 
one  compact  mounting. 

Fig.  IA  at  the  bottom  of  the  circuit 
drawing  shows  the  method  of  connecting 
up  the  resistance  coupling  units  in  com- 
pact form  when  the  resistors  and  leaks 
and  condensers  are  purchased  separately 
and  assembled  by  the  builder  of  the  set. 
Spring  clips  can  be  obtained  for  mounting 
the  resistors  and  grids  just  as  tubular 
grid  leaks  are  mounted 

Bypass  condensers  such  as  (K6)  of 
0.002  mf  capacity  and  (K7)  of  0.5  mf 
capacity  are  frequently  of  advantage 
in  reducing  the  resistance  offered  to  the 
radio  frequency  current  by  the  "B" 
battery  and  the  impedance  of  the  output 
circuit,  particularly  after  the  "B"  bat- 
teries become  old  and  dried  out.  In 
some  cases  and  using  certain  materials 
in  the  circuit,  these  bypasses  work  a 
great  improvement,  while  under  other 
conditions  their  effect  is  unnoticeable. 
However,  the  set  will  perform  better 
and  more  consistently  throughout  the 
life  of  the  "B"  batteries  when  the  by- 
passes are  used  than  when  they  are  not 
installed. 

Materials  Used 

ALMOST  anvof  the  standard  materials 
advertised'  in  RADIO  AGE.  can 
be  used  for  this  circuit,  and  as  it  is  against 
our  policy  to  recommend  one  make  of 
apparatus  over  another,  we  cannot 
specify  any  particular  make  in  these 
specifications.  The  only  effect  that  will 
be  caused  by  changing  parts  will  be  on 
the  values  of  the  bypass  condensers, 
and  this  is  always  more  or  less  of  an 
experiment  in  any  case.  However,  the 
bypasses  are  quickly  and  cheaply  shifted 
about,  and  this  should  prove  no  objection 
to  the  user.  Experience  will  show  that 
it  is  very  seldom  that  any  one  value 
of  bypass  will  apply  to  all  conditions  in 
any  circuit. 

In  the  accompanying  list  I  have  given 
the  number  of  parts  needed  and  their 
size,  all  items  being  given  a  letter  cor- 
responding to  the  lettering  on  the  draw- 
ings so  that  their  location  can  be  quickly 
identified. 

Assembly  of  Set 

'"PHIS  receiver  will  assemble  easily  on 
-"-  a  7"x26"  panel,  and  by  a  little  crowd- 
ing  can    be    put   on    a    7"x24"    bakelite 


or  hard  rubber  panel.  The  inside  dimen- 
sion of  the  cabinet  (depth)  should  be 
at  least  seven  inches  to  accommodate 
the  apparatus.  Care  should  be  taken 
not  to  crowd  the  radio  frequency  trans- 
formers RFT-1-2-3  too  close  together 
and  the  tubes  should  be  well  oustide 
the  magnetic  field  of  the  transformers 
to  prevent  back  coupling  between  the 
stages.  The  panel  thickness  should  be 
at  least  3-16  inch  so  that  it  will  not  be 
necessary  to  cut  down  screws  or  shorten 
the  shafts. 

In  arranging  the  reflexed  part  of  the 
circuit,  see  that  the  untuned  transformer 
(RFX)  is  placed  as  close  to  the  tube 
(T3)  as  possible,  so  that  the  line  from  the 
post  (G)  on  the  transformer  to  the  (G) 
post  on  the  socket  is  very  short.  This 
is  important.  Again,  keep  (RFX)  well 
away  from  (RFT-3)  and  the  audio  trans- 
former (AT).     If  these  parts  are  so  close 


Are    You    Going    to    Take 

a    Radio    Set    with 

You  on  your 

Vacation  This  Year? 

Watch  this  and 

future  issues  of 

RADIO  AGE 

for    the    latest    in 

Portable    Receiving    Sets 

and  Accessories. 

Another   Portable   Article 
in   May   RADIO  AGE. 


that  they  are  coupled  by  the  magnetic 
flux,  there  will  be  trouble.  The  crystal 
detector,  which  is  of  the  fixed  or  semi- 
fixed type,  can  be  placed  in  such  a  posi- 
tion that  it  does  not  complicate  the 
wiring,  say  near  the  rear  edge  of  the 
bottom  board.  It  is  not  advisable  to 
put  the  crystal  detector  on  the  panel, 
as  it  is  likely  to  be  knocked  out  of  ad- 
justment every  time  we  handle  the  dials. 

The  coupling  resistances  for  the  audio 
stages  are  small  and  easily  disposed  of 
in  the  arrangement,  and  as  shown  in 
Fig.  2  these  audio  coupling  units  are 
placed  quite  close  to  the  two  audio- 
tubes  (T4)  and  (T5).  All  of  the  arrange- 
ment should  be  made  with  an  eye  to 
simple  wiring  and  simple  connections. 
You  will  not  go  far  wrong  if  you  follow 
the  diagrams  in  every  detail. 

A  voltmeter  (VM)  is  very  useful  in 
a  five  tube  set  for  keeping  the  potential 
constant  across  the  filaments  as  advised 
by  the  makers  of  the  tubes.  As  shown 
in  the  diagrams,  the  voltmeter  registers 
the  potential  across  the  filaments  of  the 
radio  frequency  and  reflex  tubes,  as 
these  tubes  are  the  most  critical  of  the 
series  and  require  the  most  accurate 
adjustment  for  the  filament  control. 
Cutting  the  large  hole  for  the  body  of  the 
voltmeter  is  a  problem  for  the  home 
mechanic    unless    he    has    some    form    of 


"fly-cutter"  for  the  job.  However,  this 
can  be  cut  by  any  machine  shop  or 
radio  store. 

Unless  the  transformers  (RFT)  are 
marked  at  the  connection  post  by  the 
makers,  the  builder  often  has  trouble 
from  "bucking"  or  opposed  coils.  If 
you  do  not  think  that  you  are  getting 
the  proper  volume  or  the  distance,  try 
the  effect  of  reversing  the  connections 
to  the  primary  of  these  coils,  one  by 
one.  In  fact,  it  is  best  to  connect  up  the 
transformers  temporarily  with  small 
insulated  wire  until  you  are  certain  that 
the  polarities  of  the  transformers  are 
correct. 

All  crystals  do  not  work  equally  well 
when  reflexed,  and  for  this  reason  it  is 
best  to  get  some  sort  of  a  crystal  detector 
in  which  the  crystals  can  be  easily 
changed.  With  a  small  stock  of  crystals, 
say  five  or  six,  experiment  until  you  find 
the  best  crystal.  Crystals  do  not  cost 
much  and  they  may  be  the  reason  your 
circuit  is  not  functioning  as  it  should. 
After  the  crystal  detector  is  once  ad- 
justed, and  put  in  an  out-of-the-way 
place  where  it  is  not  likely  to  be  dis- 
turbed, it  will  require  very  little  attention. 

Use  Care  in  Building 

I"  AM  sure  that  if  you  construct  this 
■*-  receiver  with  care  and  use  judgment 
in  the  operation  of  it,  you  will  get  ex- 
ceptionally fine  results.  Its  freedom  from 
distortion  and  extreme  sensitiveness  are 
remarkable.  Stations  from  both  coasts 
have  been  heard  repeatedly  on  the  loud 
speaker  from  my  laboratory  here  in 
Chicago. 

As  I  stated  before,  Professor  Hazel- 
tine's  original  neutrodyne  was  of  the  re- 
flexed type,  but  for  some  reason  little 
interest  was  taken  in  it.  Why  this  should 
be  is  hard  to  explain.  I  suppose  the  rea- 
son is  that  most  fans  were  a  little  bit 
afraid  of  the  reflex  circuits.  We  really 
have  no  reason  to  fear  them,  as  they  are 
quite  simple.  It  just  requires  a  little 
patience  to  get  them  to  operate  correctly. 
Most  of  the  trouble  experienced  seems 
to  be  in  getting  fixed  and  by-pass  con- 
densers of  the  right  capacity.  However, 
these  are  cheap  and  if  the  builder  will 
supply  himself  with  a  selection  of  these, 
he  can  change  the  capacities  of  each  in 
the  different  parts  of  tne  circuit  until  the 
best  results  are  obtained. 

One  of  the  probable  reasons  for  the 
clear  tone  of  this  receiver  is  the  resistance 
coupled  method  of  amplifying  after  the 
detector.  To  those  who  have  not  tried 
this  system  of  increasing  the  signal 
strength  to  loud  speaker  volume,  this 
system  will  be  a  revelation.  All  distortion 
and  transformer  noises  will  be  eliminated. 
If  you  are  undecided  as  to  whether  or  not 
you  shall  use  resistance  coupling,  my 
advice  to  you  is  tc  try  it  by  all  means. 


Another  Blueprint  Sensation 
In  May  Radio  Age 


PLA. 


CWC/4GO,  /LL. 


JS-)  BOTroAf  ea/9^0 


\9\  -         Hs  ^4 


Fig.2 

4M PL  EX.   RE  FLEX  ED  RADIO  FREQUENCY  Se  T 

TOf  WEW  SHOWS  f?E/}f?  ELEMT/OA/  OE  &4NEL  W/TH  04/VEL  MOU/V7=- 
-ED  rfEEW&ITVS.    LOWE&  I//EW  /S  s}  FL/J/V  V/EW  LOO/TIM6 £>OWM  ON 


•J.  0.  /^-Tr/vec/v 


Rear  Ele^ 

w  of  Panel 

f*>N£-L  W    , 


"<Hs 


pL0  f£W 


COF-YWGHT  /9?S 

CWC^GO,  /LL.  J 


Fie.  2 

^mrlex  Re  flexed  Rxidio  Frequency  Se  t 

TOf=  WEW  SHOWS  /?£*/?  ELEMT/O/V  OF FHHEL  W/TH  FK/VEL  MOV/VT- 

-ep  s>pfwf>atus.  towee  new  /s  *> f-lm  y/ew  Loo/rwe oow/v o/v 


42 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Radio  Age  Institute 

Manufacturers'  Testing  Service 

MEMBERS  of  the  staff  of  RADIO  AGE  will  be  pleased  to  test  devices 
and  materials  for  radio  manufacturers  with  the  object  of  deter- 
mining their  efficiency  and  worth.  All  apparatus  which  meets  with 
the  approval  of  various  tests  imposed  by  members  of  the  technical 
staff  of  RADIO  AGE  will  be  awarded  our  endorsement,  and  the  seal 
shown  to  the  right  will  be  furnished  free  of  charge.  Materials  for 
testing  should  be  sent  to 

RADIO  AGE 

504  N.  Dearborn  Street, 


INSTITUTE 

Chicago,  111. 


DEVICES 

displaying  this  seal 
have  been  tested 
and  approved  by 
the  RADIO  AGE 
INSTITUTE. 

Apparatus  illus- 
trated  and  des- 
cribed below  has 
successfully  passed 
our  tests  for  April 
1925. 


Test  No.  37.  The  DURAD  BASE.  Submitted 
by  the  Duraplate  Company,  of  Philadelphia,  Pa. 
For  the  experimenter  and  manufacturer  this  base  will 
be  found  to  be  very  convenient.  It  consists  of  a 
moulded  base-board  with  the  "A",  "B",  and  "C" 
battery  wires  imbedded  in  it.  The  large  number  of 
holes  along  the  side,  with  the  wires,  allows  for  con- 
nections in  many  places.  Special  connections,  bind- 
ing posts,  panel  fittings  and  brackets  are  furnished 
with  the  base-board.  Wiring  a  set  with  this  base- 
board is  greatly  simplified,  and  the  finished  job  pres- 
ents a  commercial  appearance.  This  baseboard  can 
be  secured  in  various  sizes  from  the  manufacturer 
whose  address  is  given  above.  Tested  and  approved 
by  RADIO  AGE  Institute 


Test  No.  38.  KEYSTONE  INDUCTANCE 
SWITCH.  Submitted  by  the  Keystone  Radio  Com- 
pany, Greenville,  Penna.  Keystone  Back  Mounting 
Inductance  Switch  is  constructed  of  the  best  materials 
and  is  well  adapted  to  the  purposes  for  which  it  was 
designed.  The  switch  has  ten  points,  and  all  tap 
leads  are  soldered  to  solder  lugs  before  mounting  on 
panel.  It  is  furnished  with  a  two-inch  black  metal 
dial  with  large  tapered  knob.  Dial  is  numbered  to 
coincide  with  contacts  and  it  is  only  necessary  to 
drill  one  5-16  inch  hole  in  panel  to  mount.  Arrived 
in  excellent  condition  and  satisfactorily  passed  the 
tests  and  requirements  of  RADIO  AGE  Institute. 


Test  No.  39.  THE  ELECTRAD  "VARIOHM." 
A  variable  grid  leak  manufactured  by  the  Electrad 
Co.,  428  Broadway.  New  York  City,  N.  Y.  This 
grid  leak  is  quite  small  and  takes  up  but  little  space 
either  on  the  panel  or  inside  the  set,  for  base  or  panel 
mounting  as  desired.  The  instrument  covers  a 
complete  range  of  resistance  ranging  from  less  than 
one-quarter  "to  thirty-five  megohms.  It  is  non- 
microphonic,  moisture-proof  and  absolutely  guaran- 
teed against  wear.  Provision  is  made  for  the  mount- 
ing of  the  grid  condenser  directly  to  the  leak.  This 
is  a  very  desirable  feature.  Tested  and  approved  by 
RADIO  AGE  Institute. 


Test  No.  40.  HEN- 
NINGER  AERO- 
COIL.  Manufactured 
by  the  Henninger  Radio 
Manufacturing  Compa- 
ny, 1772  Wilson  Ave., 
Chicago,  111.  Theseair- 
core  transformers  were 
tested  in  our  laborator- 
ies and  found  to  be  very 
efficient.  No.  22  D.C.C. 
wire  is  used  in  winding 
both  the  primary  and 
the  secondary.  This  re- 
duces the  high  frequen- 
cy resistance  to  a  mini- 
mum. Exactly  the  cor- 
rect air  spacing  between  turns.  Tested  and  approved 
bv    RADIO    AGE  Institute. 


Test  No.  41.  TELOS  RADIO.  A  kit  manu- 
factured by  the  Danziger-Jones  Co.,  of  25  Waverly 
Place,  New  York,  N.  Y.  The  manufacturers  ad- 
vertise this  kit  as  "The  Kit  of  a  Thousand  Possibil- 
ities," and  we  must  say  that  they  are  absolutely 
correct.  For  selectivity  and  clarity  of  tone  this 
receiver  cannot  be  excelled.  The  kit  is  the  most 
complete  one  on  the  market,  everything  necessary 
being  included.  The  circuit  has  three  stages  of 
tuned  radio  frequency  and  super-imposed  (reflex) 
resistance  coupled  audio  frequency  amplification. 
A  crystal  detector  can  be  used  if  the  builder  so  desires, 
thus  making  for  economy  of  operation.  By  means 
of  an  adjustment  known  as  the  uni-control,  it  is 
possible  to  adjust  all  tuning  controls  simultaneously. 
Arrived  in  excellent  packing  and  satisfactorily  passed 
the  tests  and  requirements  of  RADIO  AGE  I  nstitute. 


Test  No.  42.  BREMER  TULLY  LOW  LOSS 
TUNER.  One  of  the  most  efficient  three-circuit 
tuners  on  the  market.  This  unit  may  be  used  to 
tune  practically  any  radio  circuit.  It  consists  of  an 
untuned  primary,  a  main  or  secondary  inductance, 
and  a  tickler  or  "feed  back"  coil.  All  these  coils  are 
brought  to  separate  taps  and  may  be  connected  in 
any  combination.  The  method  of  winding  and  sup- 
port of  the  secondary  coil  offers  a  most  selective 
tuning  unit,  and  also  the  greatest  wavelength  range 
without  taps.  With  a  variable  condenser  of  250 
M.  M.  F,  the  entire  broadcast  wavelengths  are 
covered  in  a  very  efficient  manner.  (200  to  565 
Meters).  The  untuned  primary  is  of  adjustable 
coupling,  and  may  be  adjusted  for  volume  and 
selectivity  to  suit  any  antenna.  Pigtail  connections 
to  rotor,  insure  reliable  service.  The  tuning  unit 
was  submitted  by  the  manufacturers,  The  Bremer 
Tully  Co.,  532  South  Canal  St.,  Chicago,  Illinois. 
Arrived  in  excellent  condition,  and  satisfactorily 
passed  the  tests  and  requirements  of  RADIO  AGE 
Institute. 


Test  No.  43.  THE  AMPL-TONE  HEADSET. 
Manufactured  by  the  Union  Fabric  Company,  of 
Derby,  Conn.  This  headset  is  of  the  conventional 
type,  with  metal  shells.  A  leather  covered  wire 
head-band  is  used.  The  instrument  works  well 
throughout  the  entire  audio  frequency  range  and 
responds  with  maximum  efficiency  in  a  neighborhood 
of  2,400  cycles.  Arrived  in  excellent  condition  and 
satisfactorily  passed  the  tests  and  requirements  of 
RADIO  AGE  Institute. 


Test  No.  44.  BALL-GRIP  SOCKET,  Manu- 
factured by  the  Quality  Molded  Products,  Inc.,  1 
Exchange  Place,  J  ersey  City,  N.  J .  There  are 
several  outstanding  features  about  this  socket  that 
will  recommend  it  to  the  radio  set  builder.  It  is 
constructed  of  a  high  grade  dielectric,  which  places 
the  losses  at  a  minimum.  Contact  on  the  tube 
prongs  is  made  with  the  aid  of  a  sterling  silver  ball. 
As  all  the  contact  parts  are  completely  insulated,  one 
from  the  other,  there  is  no  possibility  of  internal  short 
circuiting.  Only  the  terminal  set  screws  are  exposed, 
offering  the  minimum  of  metal  parts  to  the  danger  of 
short  circuits.  The  terminals  on  the  socket  are  both 
novel  and  efficient.  No  soldering  lugs  are  necessary. 
The  wire  is  inserted  and  tightened  by  means  of  the 
set  screws  provided  for  that  purpose.  All  metal 
parts  are  silvered.  Arrived  in  good  packing  and 
satisfactorily  passed  the  tests  and  requirements  of 
RADIO  AGE  Institute. 


Test  No.  45.  BARRETT  &  PADEN  VARIABLE 
CONDENSER.  Practically  no  other  condenser  on 
the  market  gives  the  fine  vernier  tuning  that  it  is 
possible  to  obtain  with  this  condenser.  It  has  an 
absolute  straight-line  wavelength  curve,  and  this, 
coupled  with  the  micrometer  adjusting  feature,  makes 
it  possible  to  separate  wavelengths  that  could  not  be 
separated  with  the  ordinary  type  of  condenser. 

The  losses  in  this  condenser  were  practically  not 
measureable,  being  only  equivalent  to  a  series  resis- 
tance of  Two  Hundred  Ohms.  The  condenser  was 
submitted  by  the  Barrett  &  Paden  Co.,  of  1314 
Segdwich  St.,  Chicago,  111.  Arrived  in  excellent  con- 
dition and  passed  the  tests  and  requirements  of 
RADIO  AGE  Institute. 


Test  No.  46.  ENSIGN  VARIABLE  CONDEN- 
SER. Submitted  by  the  Carleton  Sanders  Mfg. 
Co.,  Mishawaka,  Ind.  This  condenser  is  a  radical 
departure  from  the  ordinary  type,  of  rotarv  plate 
design,  both  the  fixed  and  movable  plates  being 
square,  as  the  illustration  shows.  The  movable 
plates  are  meshed  with  the  stationary  by  means  of 
a  rack  and  pinion  arrangement,  making  use  of  the 
entire  360  degrees  of  the  dial.  The  minimum  capa- 
city of  this  condenser  is  5.99  mmf.  and  the  maximum 
capacity  is  539.06  mmf.  The  dielectric  absorption 
losses  at  1,000  cycles  with  the  instrument  set  at 
maximum  capacity  are  equivalent  to  a  series  resis- 
tance of  50  ohms.  Arrived  in  excellent  packing. 
Tested  and  approved  by  RADIO  AGE  Institute. 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour  43 


cartel  _ 

HooXc^"ULp43 


qpHE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers" 
■*■    contributed  by  our  readers.      It  is  a  department  wherein  our  readers  exchange 


RADIO  AGE.  is 
by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con 
tributors,  but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


BY  the  time  this  issue  reaches  you, 
several  things  will  have  happened, 
and  several  more  will  be  scheduled 
to  happen  that  will  please  all  ct  us 
mightily. 

For  one  thing,  Spring  will  be  with  us. 
After  Spring,  Summer  will  be  but  a  sho^t 
way  off,  and  it  might  be  wise  for  us  to 
prepare  for  it  now. 

When  we  think  of  Summer,  we  immed- 
iately dream  of  the  many  pleasant  camp- 
ing trips,  fishing  trips,  auto  tours,  and 
other  diversions  too  numerous  to  men- 
tion. 

Radio  has  by  this  time  become  a  very 
necessary  part  of  our  lives,  and  steps 
must  be  taken  now  to  see  that  we  are  not 
denied  any  of  its  advantages  and  privi- 
leges on  any  of  the  expeditions  that  I 
mentioned  before.  Think  how  much 
more  wonderful  will  be  the  evenings  spent 
around  the  camp  fires,  listening  to  won- 
derful dance  and  concert  music  from 
stations  hundreds  of  miles  away!  Al- 
though the  very  thought  of  the  camp  fires, 
without  the  radio  receiving  set  is  a  most 
pleasant  one  now,  I  am  sure  that  if  we 
have  not  our  "trusty  radio"  set  with  us 
when  the  time  arrives,  that  we  shall  be 
very  much  disappointed. 

For  that  reason  I  think  it  is  about  time 
that  most  of  us  were  beginning  to  either 
rebuild  the  old  set,  and  convert  it  into 
a  portable,  or  build  the  portable  receiver. 
If  we  start  now,  we  can  be  sure  of  having 
it  functioning  perfectly  when  the  time 
arrives  for  its  use. 

So  "come  on",  you  Dial  Twisters  and 
experimenters,  and  let  the  brother  fans 
have  all  the  "dope"  you  have  on  these 
portable   outfits. 

As  you  are  no  doubt  aware,  the  ideal 
receiver  will  be  one  that  uses  dry  cells  as  a 
source  of  filament  current,  operates  on  a 
loop,  and  last  but  not  least,  is  small 
enough  in  size  to  be  practical.  These 
specifications  are  not  impossible,  and  I 
am  sure  that  by  the  time  the  next  issue 
of  RADIO  AGE  is  ready  for  the  press, 
we  will  have  had  a  number  of  good  cir- 
cuits submitted  to  us. 

Another  thing  that  comes  with  Sum- 
mer will  be  our  old  friend  "static." 
Now  is  the  time  to  prepare  for  his  ad- 
vance and  to  take  means  to  prevent  him 
from  spoiling  our  reception.  We  do  not 
expect  quite  as  much  interference  from 
him  this  year  as  we  had  in  previous  years 
as  a  large  number  of  circuits  have  been 
perfected  that  practically  eliminate  him 
from  our  troubles.  A  few  reports  from  the 
fans  who  have  been  using  these  circuits 
will  be  appreciated. 

Well,  fellows,  that's  about  all  for  this 
month,  except  to  remark  that  we  have 
had  some  dandy  DX  lists  submitted,  and 
I  am  sure  you  will  have  plenty  of  marks 
to  shoot  at.  And  as  the  time  is  drawing 
rapidly  to  a  close  when  we  can  prowl 
around  for  extremely  long  distance  re- 
ception,   let's    go! 

THE    PICK-UPS    EDITOR. 


CHAUNCEY  DePEW 
Alpena,  Mich. 

Name 
Gaspar  A.  CarvajaL 

CONTRIBUTORS 

E.  H.  JONES 
Muncie,  Ind. 

DIAL   TWISTERS 
Address 

1 

WM.   VREELAND 
Montclair,  N.  J. 

City 
Havana,  Cuba 

J.  A.  Fortier 

.—117  14th  Ave.,  E 

Calgary,  Alta.,  Can. 

935  27th  St. 

Arthur  Cantrell 

....20  Orchard  St. ..7 

Auburn,  N.  Y. 

H.  A.  Cassin 

....2292  "B"  St 

Montreal,    Que.,    Can. 
Piqua,  Ohio 

Joseph  A.  Gillem 

Lyle  Anderson 

Neal  F.  Coleman.. 

Allen  J.  Martzolf. 

....345  Haight  St 

....378  Union  St 

... .9  E.  Drullard  Ave 

San    Francisco,     Calif. 
St.  John,  N.  B.,  Can. 
Lancaster,  N.  Y. 
Corona,  L.  I. 
Simcoe,  Ont.,  Can. 

Chas.  F.  Maryott 

-...43  No.  Junction  Ave 

W.  A.  Wallace 

F.  W.  Clute 

....22  Hampden  PI 

Utica,  N.  Y. 
Fredonia,  N.  Y. 
Pasadena,  Calif. 
Buffalo,  N.  Y. 
Detroit,  Mich. 
Elgin,  111. 
—.Melrose,  Mass. 

Josselyn  Eddy 

—.226  Temple  St 

Paul  M.  Hayes 

-.918  Bell  St 

W.  M.  Hammersly 

John  Skewis _ 

—.344  Cornwall  Ave 

...1731  Beaufairt,  Ave 

Marvin  Joseph 

—472  No.  Liberty  St 

Malcolm  Sampson.. 

D.  P.  Finch 

....70  Lynde  St 

New  Haven,  Conn. 

Robt.  Jiricker 

Daniel  Smith __ 

....4956  Margaretta  Ave 

St.  Louis,  Mo. 
Southold,  N.  Y. 
Roanoke,  Va. 

Hubert  H.  Moler 

Earnest  E.  McLaughlin 

....National  Home,   Wise. 

—3125  W.  Augusta  St 

Chicago,  111. 
Smith  Basin,  N.  Y. 

Paul  Tilford-..- 

H.  W.  Klotz 

.     77  Pastorious  St. 

Martin  Wider. _ 

—  708  E.  5th  Ave 

Mitchell,  So.  D. 
... .  Arvada,  Wyo. 

....6200  Dorchester  Ave 

Chicago,  111. 

....34  Gill  St.„ 

Ivan  H.  Ball 

Harry  L.  Dague 

Don  McGregor. 

Geo.  H.  Chrestian 

—  100  Rand  St 

—R.  F.  D.  No.  1 

Rochester,  N.  Y. 
... .Bentleyville,  Pa. 

...-108 18  Hull  Ave..  

....8015  Euclid  Ave 

Cleveland,  Ohio 
Cleveland,  Ohio 

..  .1311  E.  Condit  St 

J.  Hinchliffe       

—610  Birch  St 

L.  A.  Lynch 

—469  Chenango  St 

... .Binghamton,  N.  Y. 

Shreveport,  La. 
—San   Francisco,   Calif. 

Willie  Jones — 

..-1233  Reynold  St 

—  1319  Third  Ave 

F.  G.  Orton 

L.  Bennett  Knouff. 

—  15914  Lasher  Rd 

—2001  Tremont  Rd 

.-..Columbus,  Ohio 
Atlanta,  Ga. 

T.  E.  Kingston 

Lee  W.  Burton  

....Gate  City  Hotel 

...672  Seventh  St.... 

Milwaukee,  Wis. 

Some  time  ago  RADIO  AGE  discon- 
tinued its  policy  of  printing  lists  of  "Sta- 
tions heard"  by  readers,  due  to  lack  of 
space.  However,  a  new  system  has  been 
devised  whereby  we  shall  be  able  to 
revert  to  this  popular  policy,  and  as  a 
result    the    best     DX    records    received 


will     be    compiled    and 
May   issue   of    RADIO 


during  March 
printed  in  the 
AGE. 

This  ought  to  serve  as  an  incentive  to 
those  fans  who  have  been  growing  lax 
with  their  DX  stunts  lately.  (Turn  the 
page.) 


44 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


A   Novel    Radio    Frequency    Receiver 

Chauncy  De  Pew,  of  Alpena,  Mich., 
has  given  us  an  interesting  circuit,  that 
employs  radio  frequency  amplification 
in  quite  a  novel  manner.  A  variometer 
and  condenser  are  used  to  tune  the  cir- 
cuit. His  letter  is  as  follows: 
RADIO  AGE, 
Gentlemen: 

For  the  past  year  I  have  been  using 
the  circuit  described  herein,  and  have 
had  very  good  results  with  it.  I  have 
never  seen  it  in  print,  and  for  that 
reason  I  do  not  think  that  there  are 
many  of  the  fans  who  have  ever  heard 
of  it.  It  was  originally  given  to  me 
by  an  "old  time"  radio  man,  and  as 
he  still  uses  it  I  think  it  might  be 
worth  while  to  pass  it  along  to  the 
readers  of  the  Dial  Twisters'  columns. 
The  apparatus  needed  for  construc- 
tion, can  usually  be  found  in  any  radio 
experimenter's  workshop.  The  set 
is  very  easy  to  construct  and  once  you 
get  "the  hang"  of  operating  it,  you 
will  find  that  it  is  a  regular  DX 
receiver.  Many  of  the  so-called  DX 
circuits  can  in  no  manner  compare 
with  my  little  two-tube  "nameless." 
The  variometer  is  of  the  series  type, 
and  should  be  of  the  best  kind  obtain- 
able. The  radio  frequency  transformer 
consists  of  two  honey-comb  coils,  the 
primary  side  being  a  coil  having 
fifty  turns,  and  secondary  having 
but  thirty-five  turns.  Across  the 
primary  coil  is  a  condenser  having  a 
capacity  of  .0005  mfd.  The  coils 
can  be  mounted  on  a  double  coil 
mounting,  so  the  coupling  between 
them  can  be  varied  until  the  best  set- 
ting has   been   found. 

There  is  not  much  more  to  be  said 
regarding  this  circuit,  except  that 
I  might  tell  you  of  some  of  the  distant 
stations  that  I  receive  with  quite  a 
little  bit  of  regularity.  WOC,  KDKA, 
KFKX,  KTHS,  KYW,  WGN,  WBAP, 
and  WBS  are  stations  that  I  can  get 
at  will.  On  WOC,  KDKA,  or  KFKX, 
I  can  rest  the  headset  on  the  table 
and  hear  the  stations  plainly  at  a 
distance   of  fifteen   feet. 

Yours  verv  turly, 
CHAUNCEY  DE  PEW 

Alpena,  Mich. 

The  same  receiver  as  described  by 
Mr.  De  Pew  should  be  quite  selective, 
and  he  seems  to  be  a  little  bit  proud 
and  a  little  bashful  about  disclosing  his 
DX  list.  Perhaps  the  circuit  is  as  efficient 
as  he  says.  There  is  no  doubt  but  what 
the  set  can  be  constructed  easily,  and  for 
that  reason  we  are  going  to  pass  it  along 
to  some  of  our  brothers  who  "crave"  DX. 


William  Vreeland,  of  67  Union  street, 
Montclair,  N.  J.,  wishes  us  to  pass  this 
circuit  along  to  the  readers  of  the  D.  T. 
columns.  He  has  found  this  set  very 
effective,  ami  would  like  to  hear  from  any 
of  you  who  will  experiment  with  it.  His 
letter  is  as  follows: 

RADIO  AGE, 

Gentlemen: 

I  am  sending  you  a  diagram  of  a  small 
receiver  which  I  find  to  have  good  tone, 
volume  and   DX  qualities. 

You  will  also  find  enclosed  a  list  of 
stations  that  I  heard  one  evening  from 
9:00  p.  m.  to  10:15  p.  m.  They  are  as 
follows:  WDAR,  WIP,  WTAS,  KDKA, 
WSAI,  WEBH,  WREO,  WPO,  WGY, 
WMH,  WBZ,  WJAR,  WLS,  WEBH, 
WEAN, KFKX,  WEAO,  WSAD,  WQAM, 
WRK,  WOAW,  KYW,  KSD,  KFKB, 
and    WOC. 

Not  so  bad  for  an  hour  and  a  quarter 
on   a   one  tube   set.      I   wish   you   would 


Ik  "4 


/ff 


o 

B-    ,34.9 +■ 


O     6 


Chauncey  De  Pew's  Radio  Frequency  Receiver, 
RADIO  ACE  passes  it  on  to  you. 


[iven  to  him  by  an  "old  timer,"  and 


publish  this  circuit  for  the  benefit  of  the 
fans  who  want  a  sensitive  yet  low  priced 
set. 

William     Vreeland. 
67    Union    Street,    Montclair,   N.  J. 

Mr.  Vreeland  calls  his  circuit  the 
"Audiodyne."  The  tuning  inductance 
is  wound  on  a  four  inch  tube,  the  pri- 
mary consists  of  ten  turns  of  No.  22 
D.  C.  C.  wire  and  the  secondary  consists 
of  fifty  turns  of  the  same  size  wire.  A 
variable  vernier  condenser  is  placed 
across  the  secondary.  The  grid  conden- 
ser should  have  a  capacity  of  .00025  and 
the  grid  leak  will  be  about  two  megohms. 
A  variometer  is  placed  in  the  plate  cir- 
cuit   for    regeneration. 

Any  of  you  fellows  who  want  a  good, 
sensitive  circuit  and  do  not  care  to  "sink" 
a  lot  of  money  in  new  apparatus  are 
advised  to  try  the  circuit  contributed  bv 
Bill. 


Another  one  of  our  contributors  this 
month  is  Ernest  H.  Jones  of  315  Wheeling 
Ave.,  Muncie,  Ind.  The  outfit  he  de- 
scribes is  a  simple  one,  and  from  all  re- 
ports a  good  one. 

Using  this  circuit  he  has  heard  the 
following  stations:  WOS,  WBZ,  WDAF, 
WHB,  WOAW,  WAHG,  WGY,  WBAP, 
WEAF,  WMC,  WCCO,  WGR,  KFDM, 
KFNF,  WOQ,  WJY,  KFNG,  WSB, 
WJZ,  WNAC,  KGO,  WOR,  WOC, 
WJAR,  CNRO,  WJAD,  WCAL,  WLBL, 
WBBF,  WAAW,  WEEI,  KFI,  WCK, 
WFAA,  WIP,  KSD,  KFKX,  CKAC, 
KFKB,  CFCA,  WHAR,  WHAA,  WCAY, 
WCAP,  WHO,  and  WNYC. 

Here  is  his  letter: 

RADIO  AGE. 
Gentlemen: 

For  a  long  time  I  have  been  reading 
your  magazine,  or,  our  magazine,  since 
it  is  for  all  radio  fans.      I  enjoy  reading 


your   technical    articles   and   the    D.    T. 
section. 

I  have  been  afraid  to  send  in  a  list  of 
stations  heard,  but  I  can't  hold  out  on  the 
fans  any  longer.  I  am  using  a  single 
tube  set  which  I  made  myself.  It  is 
simplicity  itself,  "radiofied."  I  am  en- 
closing a  sketch  of  the  circuit  for  the 
benefit  of  anyone  who  wants  a  receiver 
that  always  works  and  works  well.  Al- 
most all  kinds  of  apparatus  will  do,  as 
long  as  they  are  electrically  sound.  How- 
ever, any  fan  should  not  hesitate  to  use 
the  best  he  can  get.  I  have  found  that 
this  policy  always  pays,  in  quantity  and 
quality  of  reception. 

I  have  built  several  sets  for  my  friends, 
using  this  circuit.  One  of  them  "copped" 
a  prize  offered  for  the  best  list  of  stations 
heard. 

The  prize  was  a  pair  of  well-known 
"phones." 

If  any  of  the  fans  who  try  this  circuit 
fail  to  make  it  work,  I  wish  they  would 
let  me  know  about  it.  I  would  be  glad  to 
answer  my  letters  relative  to  it.  How- 
ever, I  might  add  that  I  do  not  expect 
to  hear  from  any  one  from  this  cause. 
I  would  like  to  say  that  in  more  than 
two  years  of  experimenting  with  tuning 
units  and  single-tube  sets,  I  have  never 
found  one  better  than  this  one. 
Very  truly  yours, 

ERNEST  H.'JONES. 

315  Wheeling  Ave.,  Muncie,    Ind. 

Well,  fellows,  that's  his  letter,  and  it 
seems  as  though  Ernest  is  mighty  proud 
of  his  circuit.  As  he  states,  the  circuit 
is  simplicity  itself;  anyone  can  see  that 
when  he  consults  the  wiring  diagram. 
The  tuning  coil  is  wound  on  a  tube  four 
inches  in  diameter  and  consists  of  eighty 
turns  of  number  twenty-two,  D.  C.  C. 
wire,  tapped  at  the  15th,  32nd,  45th,  60th, 
and  80th  turns.  The  wiring  diagram 
is   self-explanatory   and   for   that   reason 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


45 


we  will  not  go  into  detail.  The  by-pass 
condenser  across  the  "B"  negative  and 
the  phone  connection  of  the  variometer 
should  have  a  capacity  of  .0005.  It 
might  or  might  not  be  necessary  to  use 
this,  and  the  experimenter  is  advised  to 
try  the  circuit  both  ways  to  determine 
which  is  the  more  effective. 

As  Mr.  Jones  was  kind  enough  to  offer 
his  services  to  the  fans,  we  wish  one  or  two 
of  you  would  drop  him  a  line  and  let 
him  know  just  what  results  you  are  hav- 
ing with  his  "pet  circuit." 


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.0005 


We  received  the  following  letter  from 
one  of  the  RADIO  AGE  fans  in  Havana, 
Cuba: 

RADIO  AGE, 

Editor,  Pick-Ups  and  Hook-Ups  Section, 
Dear  Sir: 

I  am  a  radio  fan  and  also  one  great 
reader  of  RADIO  AGE  because  I  think 
it  is  the  best  radio  magazine  ever  pub- 
lished. 

Everything  has  a  consequence,  and 
my  consequence  of  being  one  of  the 
many  readers  of  RADIO  AGE  is  that 
I  find  in  its  columns  a  great  quantity 
of  hook-ups,  all  of  them  of  the  first  rate. 

I  have  proved  some  of  them,  always 
with  excellent  results,  and  lastly  I  have 
make  the  "Tuned  Plate  Regenerative"  great  pleasure  to  know  with  what  results  positive  wire  to  the  "A"  negative  wire 
which  appears  in  the  blueprint  section  0ur  efforts  are  being  received  by  people  on  the  vacuum  tube  socket  "T3."  If 
of  January's  issue,  and,  "by  jingo,"  on  the  other  end  of  the  line.  Letters  you  will  omit  this  connection,  everything 
it  gives  excellent  DX,  so  "I'm  satisfied."     containing  compliments  are  a  source  of     will   work  out  correctly.     Those  of  you 

I  have  received  a  great  quantity  in  pleasure;  not  that  those  of  a  constructive,  who  follow  the  wiring  diagram,  (Fig,  1), 
United  States  and  also  Mexico  and  critical  nature,  are  not  welcome.  We  will  not  experience  any  inconvenience, 
Porto  Rico;  some  of  them  are:  KFDM,  want  to  receive  them  at  any  cost,  as  as  that  drawing  is  correct.  The  mistake 
WGY,    WMC,     WLW,     WOO,     KDKA,     they  enable  us  to  give  the  fans  just  what     was  made  only  on  the  isometric  drawing. 

WOR,     WQAM,    WEBH,_  WEAF^   and     they  want.     But  nevertheless,  a  compli-  

Arthur    Cantrell,    a   new   dial    twister, 
gives    us    the    following    list    of    stations 


The  circuit  used  by  E.    H.  Jones  and  from  which  he  has  had  some  excellent  results. 
The  coil  is  tapped  at  the  15th,  32nd,  45th,  60th  and  80th  turns. 


some  others.     I  live  near  Station  PWX 

which  comes  in  very  loud  in  the  phones, 

and    can    operate    a    loud    speaker    with 

medium   volume,    and   excellent    musical 

tone. 

I   have   an   antenna   of  two   wires,    80 

feet  long,  and   I  use  low-loss  parts. 
The  only  thing  that  I  need  now  to  be 

happy    is    to    be    one    "Dial    Twister." 

"What  I'll  do"  in  the  mean  time?,  "Ex- 
periment" is  the  best  policy. 
Very  truly  yours, 
GASPAR  A.  CARVAJAL. 
Calle,  Infanta  &  San  Miguel,  No.  18,  We    want   t0   correct    a    mistake    that 

Havana,    Cuba.  was    ma(je    ;n    tne    blueprint    section    in 

It  is  with  a  feeling  of  pride  that  we     the  February  issue.     The  draftsman^  in 

publish  the  above  letter,   as  it   gives  us     making  the  drawing,  connected  the  "A" 


ment  is  a  compliment,  and  although  we 
might  blush,  there  are  times  when  we 
like  to  blush. 

Gaspar  wants  to  become  a  member 
of  the  Dial  Twisters.  He  states  that 
it  is  the  only  thing  he  "now  needs  to 
be  happy."  Are  we  going  to  deny  him 
this  happiness?  Most  emphatically, 
NO.  We  welcome  him  to  the  "frater- 
nity "with  the  proverbial  open  arms. 
Don't  you  think  he  deserves  it,  fellows? 
He  does?      Let   him   enter. 


that  he  has  listened  to  on  his  single  tube 
"Baby  Heterodyne."  His  letter  and 
list  of  stations  are  as  follows: 

RADIO    AGE, 
Gentlemen: 

I  have  a  one  tube  "Baby  Heterodyne" 
set  made  from  RADIO  AGE  specifica- 
tions. I  think  it  is  a  great  set,  and  I 
am   having   wonderful   results  with  it. 

Enclosed  you  will  find  a  list  of  stations 
that  I  have  received.  Do  you  think  it 
will  admit  me  to  the  Dial  Twisters?  I 
have  been  trying  hard  to  obtain  a  button. 
KDKA,  WGR,  WSAI,  WGY,  WBZ, 
WAAM,  WEAN,  WCBD,  WTAM, 
WHAM,  WEBH,  WHN,  WLS,  KFKX, 
WGN,  WLW,  WTAS,  WHAZ,  WSB, 
WDAF,  WEEI,  WGAZ,  WREO,  WGBS, 
CNRO,  CFCA,  WFBI,  WFFA,  CKAC, 
WOC,  WCAE,  WEAO,  WEAF,  WJDD, 
WEAP,  WOR,  WEAR  and  WSP._ 

Not  so  very  many,  but  then  I  think  it 
is  pretty  good  for  a  single  tube  set. 
Yours  very  truly, 

ARTHUR  CANTRELL, 
20  Orchard  St., 
Auburn,  N.  Y. 

What  say,  fellows?  Does  his  list  merit 
a  D.  T.  button?  We  think  it  does,  so 
consider  yourself  admitted  to  the  order, 
Art. 


In  the  Pick-Ups  and  Hook-Ups  sec- 
tion of  the  March  issue,  in  the  wiring 
diagram  of  the  reflex  circuit  contributed 
by  Mr.  Dolan,  of  Aurora,  111.,  we  have 
shown  the  negative  terminal  of  the  "B" 
battery  connected  to  the  negative  and 
positive  terminal  of  the  "A"  battery. 
This  is  a  mistake.  And  we  wish  to 
apologize  for  any  trouble  we  might  have 
caused  you. 
Wiring,  Diagram  for  the  receiving  circuit  described  by   William  Vreeiand.     A  four         The    negative    terminal    of    the    "B" 

inch  tube  is  used  to  wind  the  tuning  inductance.     Mr.  Vreeiand  has  had  very  good  sue-    battery  should  have  been  connected  ^to 

cess  with  this  circuit,  and  for  that  reason  we  are  passing  it  along. 


the  negative   terminal    only  of   the  "A" 


46 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 

has  not  fallen  on  deaf  ears.     Take  heed 
of  the  following: 

This  incident  was  submitted  by  Alfred 
La  Cascio,  Jr.,  of  Brighton,  Mass.  It 
seems  that  during  the  International 
Test  Week  he  was  tuning  for  some  of 
the  European  stations  for  about  an  hour 
and  a  half,  one  evening,  and  couldn't 
get  a  peep  out  of  his  set.  Then  his  sister 
reminded  him  that  it  might  be  a  good 
thing  if  he  would  hook  on  his  "B"  bat- 
tery. Must  be  pretty  nice  to  have  to 
thank  one  for  giving  out  such  nice  in- 
formation.    What  say,  boys;  what  say? 


Leslie  Gould,  pioneer  radio  enthusiast  of  Bridgeport,,  Conn.,  has  invented  the  "dial- 
less"  radio  set  after  three  years  of  experimental  work.  The  new  invention  is  self-tuning 
and  worked  by  an  electric  switch  controlled  by  the  hand.  In  place  of  the  dials  is  a  long 
piece  of  ground  glass  with  the  station  letters  marked  on  it.  In  the  rear  of  the  glass  is  a 
six  volt  battery  light,  as  shown  in  the  illustration.  When  the  light  reaches  the  desired 
station  the  music  begins.  This  outfit  is  hooked  up  to  work  off  a  110  volt  alternating 
electric  light  circuit.     No  antenna  or  ground  wires  are  needed  in  Gould's  machine. 


battery.  The  positive  connection  of  the 
"A"  battery  goes  directly  to  the  tube 
socket. 


A  number  of  our  readers  have  asked 
us  to  furnish  them  with  circuit  diagrams 
of  sets  using  honey-comb  coils  as  a  tun- 
ing medium,  and  one  or  two  stages  of 
radio  frequency  amplification.  This 
is  not  an  unusual  stunt,  but  rather  one 
that  has  never  received  much  considera- 
tion from  the  average  fan. 

During  the  past  month  we  have  had 
several  letters  from  fans  in  the  different 
parts  of  the  country  who  have  used  this 
system  with  more  or  less  success.  Two 
of  them  in  particular  gave  us  very  good 
circuits,  but  we  are  unable  to  use  them 
this  month  due  to  the  lack  of  additional 
space.  However,  as  some  of  you  might 
like  to  write  them  on  this  subject,  I  am 
taking  the  liberty  of  furnishing  you  their 
names  and  addresses,  which  are,  Felix 
Frederiksen,  Delmar,  Iowa,  and  Joseph 
A.  Gillem,  Piqua,  Ohio. 


From  H.  A.  Cassin,  of  2292  B.  St., 
Hubert,  Montreal,  Ont.,  Canada,  we 
receive  a  request  urging  all  Canadian 
fans  to  send  in  their  DX  lists.  Mr. 
Cassin  believes  our  Northern  neighbors 
can  show  the  rest  of  us  a  thing  or  two 
when  it  comes  to  pulling  in  the  distant 
broadcasts.  Mr.  Cassin  also  wants  to 
hear  from  some  of  the  Old  Reliable 
Reinartz  fans.  His  list  of  stations 
enclosed  with  his  letter  wins  him  a  DT 
button. 


SUPER-HETERODYNE 

Ultradyne  —  Haynes  Griffin— Rentier 
Dealers:   Send  for  Discounts 

HUMON-ROJS 

123  W.  Madison  St  Chicago 


Some  fans  report  trouble  in  neutraliz- 
ing the  reflexed  neutrodvne  published  in 
the    January     RADIO    AGE.  Other 

report  noises  while  tuning.  The  majority 
however,  have  reported  excellent  results 
For  the  benefit  of  those  who  have  had 
trouble,  a  sure  way  to  neutralize  this 
receiver  is  as  follows: 

Disconnect  lead  "G"  from  tube  socket 
"M4." 

Disconnect  lead  "G"  from  transformer 

"T-" 

Connect  a  temporary  lead  from  "G" 

on  transformer  "T"  to  "G"  on  tube 
"ML"  This  will  make  a  regular  four- 
tube  neutrodyne  circuit  and  should  be 
very  simple  to  neutralize.  When  the  set 
is  balanced,  replace  the  leads  that  you 
disconnected  and  remove  the  temporary 
lead.  Your  set  will  then  be  neutralized. 
For  those  who  have  had  trouble  with 
noises — look  to  your  wiring  and  see 
whether  you  have  run  your  leads  parallel. 
If  so,  change  them  and  also  see  that  your 
parts  are  mounted  so  they  do  not  "fight" 
or  oppose  one  another.  It  has  been 
shown  that  if  the  parts  are  not  spaced 
properly  and  the  wiring  is  not  done 
correctly,  that  the  set  will  be  noisy  and 
the  only  remedy  will  be  to  move  the 
parts  around  until  their  correct  location 
has  been  found. 


A  Real  Dial  Twister 

C.  J.  Ahern,  Jr.,  of  Dwight,  111.,  says: 
"I  have  been  a  reader  of  RADIO  AGE 
for  about  two  years  and  during  that  time 
I  have  been  very  much  interested  in  the 
'Dial  Twisters,'  although  I  have  never 
tried  to  become  a  member.  This  is  my 
first  attempt. 

"Using  a  neutrodyne,  I  have  tuned 
in  the  enclosed  list  of  stations  in  a  single 
evening.  I  have  heard  stations  in  thirty- 
eight  states,  six  in  Provinces  of  Canada 
and  Mexico,  two  in  Cuba,  one  in  Porto 
Rico,  and  during  the  International  Tests, 
PTT  at  Paris,  France. 

"I  also  have  heard  forty-two  stations 
before  six  p.   m." 

Sounds  like  a  real  DX  "hound" 
doesn't  he,  fellows?  And  the  list  of 
stations  he  submitted  caused  us  to  raise 
the  eyebrows  a  little.  He  certainly 
deserves  reward  for  his  perseverence, 
so  here  goes  a  DT  button. 


Reflex  Fans,  Take  Notice! 

From  Los  Angeles,  Calif.,  comes  a 
letter  telling  us  all  about  a  reflex  set  that 
is  sweeping  the  West  Coast  like  wild- 
fire. This  is  a  variation  of  the  well  known 
"Harkness"  circuit.  Elmer  Kenealy, 
who  submitted  the  article,  says  that  he 
will  answer  all  letters  that  the  fans  care 
to  mail  him,  providing  they  enclose  a 
stamped,  self-addressed  envelope  for 
reply.  We  are  very  sorry,  Elmer,  that 
we  cannot  print  your  article  this  month, 
but  we  will  try  to  use  it  in  the  future. 

His  address,  by  the  way,  is  505  East 
68th  St.,  Los  Angeles,  Calif. 


Another  Interesting  Letter 

We  also  are  in  receipt  of  a  good  letter 
from  F.  Timoney,  of  428  Arctic  St., 
Bridgeport,  Conn.  In  part  he  says:  "I 
read  RADIO  AGE  every  month  and 
obtain  all  data  needed.  With  your 
easily-read  blueprints  anybody  with  a 
pair  of  hands  and  necessary  tools  could 
construct  anything  from  a  crystal  set 
to  a  super-het. 

"I  noticed  in  your  January  number 
that  the  lists  of  stations  a  reader  should 
submit  to  become  a  dial  twister  should 
be  stations  located  at  least  500  miles 
away  from  the  receiver.  I  am  sending 
in  a  list  of  stations  500  miles  or  more 
from    Bridgeport,    Conn. 

"I  think  the  list  should  entitle  me  to  a 
fair  chance  at  the  Dial  Twister  button. 
At  present  I  am  still  using  the  "Old 
Reliable"  single  circuit  type  of  receiver, 
although  I  have  tried  many  other  types 
of  hook-ups,  but  it  seems  to  me  that  I 
get  the  best  results  from  the  type  I  am 
at  present  using." 

Radio  Age  on  the  Air 

Any  of  our  readers  who  hear  RADIO 
AGE  programs  broadcast  from  Chicago, 
both  technical  and  popular,  are  requested 
to  write  us  and  let  us  know  whether  you 
like  them.  Our  technical  talks  are 
broadcast  every  Wednesday  night  from 
WTAY,  and  our  popular  programs  from 
WEBH  or  KYW,  on  nights  specified 
in  another  part  of  this  month's  RADIO 
AGE. 


Here  is  a  Hot  One 

Our    request    for    humorous   incidents 


R.  C.  Remington,  a  RADIO  AGE 
fan  from  Mt.  Morris,  111.,  built  the  DX 
regenerator  described  in  this  magazine 
some  months  back,  and  reports  unusual 
results.  Using  Paul  Thome's  home- 
made loud  speaker  as  described  in  the 
December  RADIO  AGE,  Mr.  Reming- 
ton listens  to  the  Coast  stations  nightly 
without  interference,  although  he  is 
located  half  way  between  the  strong 
stations  of  Chicago  and  Davenport. 
Atta  boy,   Rem. 

(Turn  to  page  48 ) 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


47 


How  to  select  batteries  that  run  your 
set  for  weeks  without  recharging 


Why  select  storage  batteries  by 
guesswork  and  risk  getting  one  that 
requires  charging  every  few  days? 
Buy  wisely.  Let  the  Prest'O'Lite 
Radio  Chart  guarantee  you  bat- 
teries that  fit  your  set — of  ample 
capacity  to  bring  weeks  of  fine 
reception  without  too  frequent 
recharging. 

The  above  section  of  the  master 
chart  selects  Prest-O-Lite  "A"  Bat- 
teries to  fit  all  5-volt  sets.  It 
recommends  two  sizes  for  each  set, 
depending  upon  the  days  of  service 
you  wish  between  chargings  (based 
on  the  average  use  of  your  set  of 
three  hours  a  day).  The  larger 
capacity  battery  will  be  found  more 
desirable  unless  facilities  for  fre- 
quent and  easy  recharging  are  pro- 
vided.    Consult  the  complete  chart 


at  your  dealer's  for  data  on  "B" 
Batteries  and  also  "A"  Batteries 
for  low  voltage  tubes. 

In  every  detail  of  construction — 
special  structure  plates,  highly  po- 
rous separators  and  superior  internal 
design — -these  batteries  are  made 
to  get  the  best  out  of  your  set. 
To  supply  the  dependable,  unvary- 
ing current  essential  to  fine  tuning, 
efficient  tube  operation  and  clarity 
of  reception. 

Prest-O-Lite  Batteries  offer  you 
truly  remarkable  savings.  Though 
standard  in  every  respect  they  are 
priced  as  low  as  $4.75  and  up.  They 
last  for  years  and  are  all  easily  re- 
chargeable. See  them  at  your 
dealer's  or  write  for  our  booklet, 
"How  to  fit  a  storage  battery  to 
your  set — and  how  to  charge  it."  «■'' 


THE  PREST-O-LITE  CO.,  Inc.,  INDIANAPOLIS,  IND. 
New  York  San  Francisco 

*X*  In  Canada:  Prest-O-Lite  Company  of  Canada,  Ltd.,  Toronto,  Ont. 


pr- 


Write  today  for 
this  free  booklet 

have 


Whether  you 
one-tube  set  or  most 
advanced  multi-tube 
outfit,  you'll  find  a  fund 
of  interesting  informa- 
tion in  our  booklet, 
"How  to  fit  a  storage 
battery  to  your  set — 
and  how  to  charge  it." 

This  booklet  gives 
you  the  complete  Prest- 
O-Lite  Radio  Chart — 
technically  accurate  rec- 
ommendations covering 
both  "A"  and  "B"  stor- 
age batteries  for  every 
type  of  set. 

In  addition,  there  is 
much  vitally  important 
data  on  battery  care  and 
upkeep — information 
that  any  radio  fan  will 
find  of  real  value  in 
keeping  his  set  at  its 
maximum  efficiency. 
Write  us  at  Indianapolis, 
Ind.,  for  your  copy  right 
now. 


*     Tested  and  Approved  by  RADIO  AGE     * 


48 


RADIO  AGE  for  April,  1925 


Hugh  W.  Patterson,  of  516  South 
2nd  St.,  McAlister,  Okla.,  tells  us  of  the 
good  results  he  is  having  with  his  circuit. 
He  has  received  "plenty"  DX  stations. 
Stick  to  it  Hugh;  stick  to  it. 


Received  a  letter  the  other  day  from 
an  English  amateur,  who  describes  one 
of  the  favorite  pastimes  "over  there." 
As  they  have  not  as  many  broadcasting 
stations  in  England,  Germany,  France, 
and  Holland  as  we  have  over  here,  they 
have  not  the  opportunity  of  tuning  in 
as  many  stations  in  an  evening  as  we 
have.  For  that  reason,  they  have  de- 
vised other  means  of  demonstrating  the 
selectivity  of  their  circuits.  One  of  the 
most  popular  methods,  at  present  is  to 
see  how  many  stations  they  can  log  in  a 
given  length  of  time. 

For  example,  a  certain  fan  who  lives 
in  London,  will  tune  in  the  time  signals 
from  2LO,  listen  to  them  for  fifteen 
seconds,  switch  over  to  the  French  sta- 
tion on  the  Eiffel  tower,  hold  them  for 
the  allotted  fifteen  seconds,  drop  back 
to  the  station  at  Glasgow  for  fifteen 
seconds,  and  top  it  all  off  by  bringing 
in  the  powerful  German  station  at  Berlin. 
As  these  four  stations  broadcast  the  time 
signals  simultaneously,  it  is  possible  for 
him  to  do  this  stunt.  But  just  the  same, 
we  are  willing  to  bet  it  took  quite  a  little 
bit  of  patience  to  learn  to  tune  them  in 
and  not  miss  a  "dit." 


Using  a  loop  antenna,  J.  B.  Thompson, 
1741  New  England  Ave.,  Los  Angeles, 
Calif.,  is  able  to  do  some  mighty  fine 
DX  work.  He  certainly  earned  the  DT 
button  we  are  going  to  give  him. 


James  Smith  of  587  Sibley  Street, 
Hammond,  Ind.,  is  very  anxious  to 
correspond  with  radio  fans,  along  the 
general  lines.  Some  of  you  fellows  are 
requested  to  drop  him  a  line. 


John  R.  Dell  tells  us  about  the  good 
results  and  useful  information  he  gets 
out  of  the  pages  of  RADIO  AGE. 

We  also  received  a  very  interesting 
letter  from  Harry  Dean,  Auburn,  Ind., 
who  is  loud  in  praise  of  the  receiver 
described  by  Mr.  Pearne  in  the  Decem- 
ber issue  of  RADIO  AGE.  From  his 
reports  nothing  can  be  any  better  than 
this    hookup. 


Willie  R.  Jones,  of  1233  Reynolds  St., 
Shreveport,  La.,  says  he  is  making  a 
three-tube  neutrodyne  from  RADIO 
AGE  blueprints  and  expects  wonderful 
things  from  it,  as  the  parts  he  is  using 
are  the  best  obtainable.  His  present 
set  is  one  built  according  to  RADIO  AGE 
information,  and  judging  from  the  results 
he  gets  it  would  be  hard  to  beat.  Some 
of  the  stations  he  has  logged  are  KFNF, 
WDAF,  WJJD,  WOC,  KFAF,  WSB, 
WWJ,  KYW,  WWAE,  WGN,  WREO, 
KFKX,  WLW,  WJAX,  WOAW,  WIP, 
and  KDKA.  The  list  is  so  long  that  it 
would  be  impossible  to  print  all  of  it. 


Richard  Skidmore,  of  Upland,  Calif., 
has  a  list  of  stations  that  would  make 
many  a  Western  fan  jealous.  Practically 
all  of  the  East  Coast  stations  have  been 
heard   by   him. 


Thomas  J.  Kindel,  Carlsbad,  N.  Mex., 
Radio  5ARR,  submits  a  nice  Hst  of  sta- 
tions, from  the  land  where  the  static 
"grows."  He  has  received  PWX  a 
number  of  times,  and  most  of  the  Middle 
Western    stations   come   very   regular. 


From  Baltimore,  Md.,  comes  a  list 
of  stations  received  on  a  single  circuit 
outfit,  using  a  199  tube  as  a  detector. 
J.  C.  Dunn,  who  submits  the  list,  says 
his  set  is  very  selective.  Maybe  he  could 
help  out  some  of  you  fans  who  are  not 
having  good  results  with  the  single  cir- 
cuit type  of  receiver.  His  address  is 
2518  Greenmount  Ave.  He  has  also 
listened  in  on  quite  a  few  6's;  that  is, 
amateur  stations  in  the  sixth  district. 


D.  O.  Easton,  of  Shreveport,  La.,  is 
having  great  success  with  the  "tuned 
plate"  circuit,  as  described  by  our  Mr. 
Rathbun.  He  attributes  all  his  success 
to  our  careful  description  of  the  circuit. 
But  then,  we  know  that  he  must  have 
exercised  quite  a  little  care  in  construc- 
tion or  his  results  would  not  have  been 
so    good. 


Robert  Zurlinden,  of  Canton,  Ohio, 
tells  us  of  the  wonderful  success  he  is 
having  with  his  "Ultra  Audion"  circuit. 
We  would  like  to  print  his  instructions 
for  building  it,  but  our  space  will  not 
permit.  Maybe  we  will  be  able  to  use 
it  at  some  future  date. 


COME  ON,  YOU  DX 
HOUNDS! 

Beginning  in  this  issue,  more 
space  will  be  devoted  to  the 
"Pickups  and  Hookups"  section 
than  ever  before.  We  want  to 
give  readers  of  RADIO  AGE  a 
chance  to  compare  notes  and  to 
"swap"  stories  of  their  DX-fishing 
experiences  during  the  past  few 
months. 

So  let's  go,  fans!  Send  in  your 
station  lists  and  other  data  now, 
and  we'll  see  who  gets  the  title  of 
the  Chief  Dial  Twister.  Come  one, 
come  all — sit  down  NOW  and 
address    your    communications    to 

— THE   PICKUPS   EDITOR. 


We  have  "Howdy"  songs  over  the 
radio.  And  now  comes  Wilbur  Rein- 
hard,  with  a  "Howdy"  to  RADIO  AGE, 
to  thank  us  for  the  many  good  bits  of 
information  we  furnished  him  during 
the  past  year.  You're  welcome,  Wilbur; 
come    again. 


Tom  Winn,  4219  Marcys  St.,  Omaha, 
Nebr.,  sends  a  very  good  list  of  stations 
received  by  himself  in  one  week.  He 
shows  that  he  tried  hard  to  become  a 
DT,  so  we  are  going  to  welcome  him 
into  the  "Institution." 


A.  Lalonde,  of  Winnipeg,  Man.,  Can- 
ada, must  have  a  very  good  set,  judging 
from  the  list  of  stations  he  submits  for 
his  DT  button. 


J.  Homer  McNeely,  5036  Monzall 
Ave.,  Kansas  City,  Mo.  Has  a  very 
efficient  five-tube  neutrodyne,  on  which 
he  has  heard  stations  from  coast  to  coast, 
ranging  in  power  from  ten  watts  to  1,000 
watts. 


Jerome  Davis,  Binghamton,  N.  Y., 
compliments  us  on  our  "Pick-ups  and 
Hook-ups"  section,  and  tells  us  of  the 
good  results  he  is  getting  with  a  set  built 
from     RADIO    AGE    blueprints.       "Let 


The  Magazine  of  the  Hour 

Our  Hook-Ups  be  Your  Guide,"  and 
everything  will  come  out  all  right.  He 
also  submits  a  list  of  dandy   DX  work. 


Paul  Di  Marzo,  of  Washington,  D.  C, 
submits  a  fine  list  of  DX  stations  re- 
ceived, and  wants  to  know  if  he  is  eligible 
for  a  DT  button.  Well,  Paul,  judging 
from  the  list  you  submit,  the  only  thing 
that  will  keep  you  out  of  the  DT  roster 
is  the  loss  of  the  emblem  in  the  mail. 

Willard  Zahalka,  Racine,  Wis.,  must 
be  quite  a  hand  for  reaching  out  at  the 
distant  stations.  Over  fifty  stations 
were  received  by  him  in  a  little  less  than 
a  week.  He  also  is  going  to  have  a  DT 
button  as  a  reward  for  his  perseverance. 

We  received  quite  a  little  bit  of  useful 
information  from  a  fan  in  California, 
but  as  he  did  not  enclose  all  of  the  article 
he  had  written,  we  could  not  use  it  this 
month.  He  also  failed  to  give  his  name 
and  address,  so  we  were  not  able  to  get 
in  touch  with  him  and  request  him  to 
forward  the  missing  part  of  the  article. 
If  he  will  supply  us  with  the  missing 
parts,  we  will  use  them  next  month. 


A  Real  DX  List 

Stanley  H.  Cox  of  Fulton,  Kans., 
submits  a  list  of  DX  stations  that  puts 
him  in  the  DT  column.  It  must  be  quite 
nice  to  live  in  a  location  such  as  his.  In 
his  letter  he  states  that  he  brings  in  both 
the  East  and  West  coast  with  ease.  His 
list  of  verified  stations  easily  proves  his 
claim.  So  the  little  DT  button  certainly 
does  go  out  to  him. 


Another  Fan  From  Little  Falls,  N.  J. 

We  have  another  list  of  DX  stations 
received  by  a  fan  back  in  Little  Falls, 
N.  J.,  who  is  knocking  'em  dead  with 
his  single  circuit  receiver.  The  list  of 
stations  that  he  turns  in  would  knock 
your  eyes  out  if  we  should  print  all  of  it. 
However,  we  will  mention  a  few  of  the 
"choice"  ones  and  leave  it  go  at  that. 
WOS,  KYW,  WOAW,  WLS,  KFKX 
CKY  and  a  "raft"  of  others.  Yes,  he 
gets  his  button. 


The  Wizard   Circuit 

J.  N.  Bacon,  of  Oshkosh,  Wis.,  comes 
along  with  some  praise  for  the  "Wizard" 
circuit  as  described  in  RADIO  AGE  a 
few  months  back.  He  has  built  a  number 
of  sets,  but  likes  the  "Wizard"  the  best 
of  any.  Some  of  the  stations  he  has 
received  are  WBAP,  KFKB,  WEAO, 
KLZ,  and  last  but  not  least,  KFI.  As 
he  did  not  spend  a  lot  of  money  in 
assembling  this  set,  he  is  very  much 
surprised  at  the  results  he  has  had  so 
far.  Just  another  case  of  "Let  Our 
Hook-Ups  be  Your  Guide." 

A  200  type  of  tube  is  used  as  a  detector 
by  him,  with  22  1-2  volts  on  the  plate. 
His  antenna  is  100  feet  long  (continuous) 
from  the  outer  end  down  to  the  set.  He 
uses  a  \yi  volt  "C"  battery,  with  a 
.00025  by-pass  condenser  across  the 
secondary  of  the  transformer.  One  stage 
of  audio  frequency  amplification  is  used 
to  permit  of  loud  speaker  reception. 
Any  of  the  fans  who  want  information 
on  this  circuit  are  asked  to  drop  him  a 
line,  with  a  stamped  self  addressed 
envelope  for  reply. 


That  Old  Reliable  Circuit 

A  letter  from  Lynn  Sherk,  of  Peoria, 

111.,  tells  us  of  the  success  he  is  having 

with  his  three-circuit  outfit.     This  is  the 

type   of   circuit   that   is   usually   referred 

(Turn  to  page  SO) 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour  49 


improvements  /Obsolete 
at  ONE  stroke 


PRICE  $1.10  EVERYWHERE 

Write  for 


FREE 

Hook-Ups 


# 


1.  Eliminates  hand  rheostats — 
thereby  simplifying  control 
and  giving  compactness. 

2.  Greatly  simplifies  set  wiring, 
therefore  making  for  greater 
efficiency. 

3.  Prolongs  life  of  tubes  rrom  2 
to  3  times. 

4.  No  moving  parts — therefore 
no  grinding  noises. 

5.  Permits  use  of  any  type  of 
tubes  or  anv  combination  of 
tubes. 

6.  No  filament  meters  necessary. 

7.  Brings  the  most  out  of  each 
individual  tube — automatic- 
ally— no  guessing. 

8.  Makes  perfect  tube  operation 
absolutely  fool-proof. 


AMPERITE  operates  on  the  thermo- 
electric principle.  Contains  a  specially 
treated  filament  hermetically  sealed  in  a 
ass  tube  and  surrounded  by  an  inert  gas. 
This  filament  has  the  unique  property  of 
automatically  changing  in  resistance  as 
the  "A11  battery  voltage  changes — so  that 
a  practically  constant  current  is  main- 
tained in  the  tube  filament.  Consequently 
the  tubes  are  constantly  operated  at  maxi- 
mum efficiency.  No  knob  to  turn. 
Nothing  to  get  out  of  order.  AMPERITE 
mounts  conveniently  inside  the  set. 
Really  takes  the  place  of  a  good  hand 
rheostat,  a  delicate  meter  and  an  expert 
operator.  Thoroughly  approved  by  every 
prominent  laboratory.  Used  as  standard 
equipment  in  such  sets  as  Somerset, 
Ultradyne,  Marshall,  Pfanstiehl,  Kil- 
bourne  and  Clark,  Ambassador,  Cockaday, 
Penn-C  and  numerous  others.  Perfect  for 
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*     Tested  and  Approved  by  RADIO  AGE     ¥ 


50 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


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to  as  the  "Old  Reliable."  And  judging 
by  the  list  he  submits,  it  certainly  is 
worthy  of  the  name.  KDKA,  WGY, 
KGO,  KFI  and  numerous  others.  Keep 
it  up,  Lynn,  keep  it  up.  You're  right; 
no  one  need  be  ashamed  of  the  list  you 
submit. 


Increased  Power 

Before  we  go  any  farther,  we  would 
like  to  ask  the  fans  if  they  have  noticed 
anything  here  of  late,  regarding  the 
manner  in  which  KFI  and  KGO  are 
coming  in  these  last  few  weeks.  Letters 
from  a  number  of  DT's  in  the  eastern 
part  of  the  country  telling  us  how  strong 
those  stations  are  received  by  them, 
certainly  warrants  comment  in  these 
columns.  In  Chicago  these  two  stations 
come  pounding  through  the  locals  with 
such  volume  that  it  seems  as  though 
they  were  being  relayed  through  some 
of  the  near-by  stations.  This  is  not  the 
case,  however,  as  increased  power  does 
the    trick. 


Edmonton,  Alberta,   Canada 

Chas.  Lawson  of  Edmonton,  Alberta, 
Canada,  sends  us  a  letter  telling  us  of 
the  fine  reception  he  is  getting.  He 
wants  to  become  a  DT  and  on  the 
strength  of  his  list  we  are  going  to  admit 
him  to  the  organization. 

A  very  peculiar  thing  happened  to 
him  while  he  was  repairing  a  set  for  a 
friend.  Everything  in  the  set  he  was 
repairing,  seemed  to  be  right,  no  short 
circuits,  tubes  burning,  etc.  After  ex- 
perimenting for  some  time  he  arrived 
at  the  conclusion  that  the  tubes  were 
at  fault.  Substituting  new  ones,  the 
set  functioned  perfectly.  Now,  the  most 
surprising  thing  about  this  is  that  al- 
though the  tubes  would  not  work  in  one 
set,  they  worked  perfectly  in  another. 
He  is  at  a  loss  to  account  for  this,  and 
suggests  that  perhaps  the  tickler  coil 
was  at  fault.  He  wants  to  know  if  any 
of  the  other  fans  have  experienced 
trouble  along  this  line.  Well,  Charles, 
tubes  are  funny  things  and  perhaps  the 
tickler  was  at  fault,  to  some  extent.  But 
did  you  notice  if  the  plate  connection 
from  prong  on  tube,  to  spring  on  socket 
was  at  fault?  The  fact  that  no  connec- 
tion is  made  at  this  point  on  the  detector 
tube,  will  not  permit  the  set  to  function. 

Nice   DX 

Turner  H.  McBaine,  of  Columbia, 
Mo.,  reports  that  he  has  heard,  among 
other  stations,  a  station  in  Mexico,  whose 
call  letters  he  did  not  get  plainly,  but 
heard  the  announcer  say  "The  depart- 
ment of  education,  Mexico  City,  Mo." 
He  would  like  to  know,  if  possible,  what 
the  call  letters  of  this  station  were.  On 
December  17th  he  also  received  WKAQ 
at  San  Juan,   Porto  Rico. 

Mighty  fine  DX,  Turner.  The  station 
you  heard  was  probably  CYL  as  they 
are  "on  the  air"  quite  a  little  bit.  I'll 
bet  you  had  quite  a  little  thrill  when  the 
announcer  said  WKAQ.     Did  you? 

A  Stranger  Within  Our  Gates 

We  are  in  receipt  of  a  communication 
from  Clifton  M.  Beaty,  of  Chino,  Calif., 
who  after  a  five  year  absence  from  the 
United  States,  returns  and  is  quite  a 
little  surprised  at  the  progress  radio  has 
made  in  his  absence.  He  purchased  a 
super-heterodyne  and  is  enjoying  con- 
certs from  all  the  high  power  stations 
in  the  country.  It  really  must  be  amaz- 
ing to  a  person  who  has  not  been  asso- 
ciated with  radio  for  the  past  four  years 
to  listen  in  on  some  of  the  good  things 
that  have  become  a  part  of  our  every 
day  life. 


*     Tested  and  Approved  by  RADIO  AGE     ¥ 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


51 


The  Daven  Super  Amplifier 

Now  that  you  get  "distance,"  how  about  "quality?" 
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*     Tested  and  Approved  by  RADIO  AGE     * 


52 


RADIO  AGE  for  April,   1925 


Free   Subscriptions 

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The  Magazine  of  the  Hour 

At  Last!     The  Perfect 
Announcer! 

(Continued  from  page  29) 

contains  some  unexpected  features.  Rate 
of  delivery  is  most  important,  stress 
variations  are  second,  distinctness  is 
third,  average  pitch  is  fourth,  pitch 
variations  are  fifth,  changes  in  rate  pace 
are  sixth,  and  degree  of  formality  is 
least  important  of  all. 

It  would  seem  from  the  comments 
made  by  various  members  of  the  com- 
mittee that  perfect  co-ordination  be- 
tween mind  and  vocal  muscles  is  greatly 
to  be  desired  in  any  radio  announcer, 
and  absolutely  essential  to  the  Ideal 
Impresario  of  the  Air. 

"Vowel  elongation  is  very  bad"  is  one 
terse  comment.  Provincialisms  are  not 
objectionable  in  certain  cases,  but  the 
majority  seem  to  feel  that  provincialisms 
from  only  one  part  of  the  country — 
the  South — are  desirable.  "Foreign 
dialects  are  entirely  out  of  place"  is 
another  brief  statement.  "Nasal  tone 
quality  and  harsh  tone  quality  are 
unsuitable  because  the  effect  is  un- 
pleasantly amplified  in  the  majority  of 
loud  speakers"  would  indicate  that  the 
loudspeaker  has  supplanted  the  ear- 
phone in  the  American  home  and  is  a 
considerable  factor  in  any  judgment  on 
radio  announcing  technique.  "Neurotic 
mannerisms  and  lapses  are  particularly 
distressing"  is  the  unanimous  opinion 
of  the  entire  committee. 

Lacks  One  Thing! 

'T'HE  committee  explains  further  that 
J-  this  Ideal  Radio  Announcer  lacks  one 
most  vital  factor,  which  they  are  unable 
to  give  him;  namely,  Personality.  The 
committee  presents  the  Ideal  Radio 
Announcer  to  the  entire  announcing 
profession  as  a  technically  correct  and 
perfect  being;  but  to  the  individual 
announcers  it  must  remain  to  imbue 
him  with  the  spark  of  Personality. 

It  is  the  earnest  hope  of  the  com- 
mittee that  radio  announcers  throughout 
the  country  will  be  able  to  utilize  findings 
to  advantage,  eliminating  those  technical 
faults  which  are  at  present  detracting 
from  their  "Radio  Personalities." 

As  yet  the  Radio  Voice  Technique 
Committee  has  dealt  with  the  art  of 
radio  announcing  only  in  the  abstract. 
It  has  been  essential  to  determine  what 
characteristics  constitute  perfection  in 
the  art  before  any  judgment  can  be  made 
as  to  which  of  the  more  than  fifteen 
hundred  "radio  voices"  in  the  country 
most  nearly  approach  that  perfection. 

The  committee  intends  to  crystallize 
their  opinions  in  more  concrete  form  by 
voting  on  the  best  of  present-day  an- 
nouncers in  the  future.  Whether  or 
not  it  will  be  possible  to  make  such  a 
decision  in  more  than  a  local  sense 
remains  to  be  determined  by  the  com- 
mittee. 


DO  YOU  CRAVE  JAZZ? 

Then  you  will  get  plenty  of  it  and  then 
some  if  you  listen  in  on  RADIO  AGE'S 
Jazz  Carnival  from  KYW's  Congress 
Hotel  Studio,  Saturday,  April  4,  begin- 
ning at  midnight. 


*      Tested  and  Approved  by   RADIO   AGE      * 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


MILLIONS  are  enjoying  music, 
and  entertainment  reproduced  in 
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COULD    NOT    BUY 


MONEY 

MY     SET" 

shouted  Buster  Nelson,  a  16  _year  old 
boy  of  1749  Amsterdam  Avenue,  New 
York,  N.  Y.  after  he  had  heard  KGO 
— KHJ  and  KOA  among  other  DX 
stations. 

His  enthusiara  was  prompted  by  the  result  of 
his  reception  after  replacing  a  vario-coupler,  vario- 
meter and  honey-comb  coils  with  a 

KENNEDY    TUNER 

Do  you  or  is  there  someone  in  your  home  stays 
up  half  the  night  to  get  distance? 

RESULTS  GUARANTEED 

$?         KENNEDY  TUNER 
$5.00 

If  you  are  not  satisfied  with  results  after  30 
days    your    money   will    be    cheerfully    refunded. 
Following  reception  certified  by  Radio   Broad- 
cast: 

2LO  London,  England     5WA  Cardiff,  Wales 
PTT  Lyons,  France         SNO  Newcastle 
Kennedy  Tuner  users  are  satisfied.     Send  $5.00 
and  go  to  bed  early. 

T.  J.  KENNEDY,  (Radio  Globe  Trotter) 
1360  University  Avenue  New  York,  N.  Y. 

T.  J.   Kennedy   (Radio  Globe  Trotter) 
1360  University  Avenue, 
New  York,  N.  Y. 

Enclosed  find  S5.00  (M.  O.  or  Check).  Send 
me  your  Tuner  and  Globe  Trotter  Diagram.  If 
I  am  not  satisfied  after  30  days  trial,  you  agree 
to  refund  my  money. 

Name — — 

Address - 

City.__ State. 


A  Four-Tube  Regenerative  Receiver  that  Goes  Lightly  on  the  Squeals!  You  may  think  it  can't  be  done,  but 
Arthur  B.  McCullah  has  devised  a  new  hookup  of  the  regenerative  type  that  shows  some  consideration  for  your 
neighbors.  He  has  written  it  for  RADIO  AGE  readers  and  it  will  appear  in  our  May  issue — on  stands  April  15. 

¥     Tested  and  Approved  by  RADIO  AGE     # 


54 


RADIO  AGE  for  April,  1925 


6pQ&$Q{ 


DID  you  ever  look  the  tube  ques- 
tion square  in  the  face?  Ever 
stop  to  realize  that  the  vacuum  tube 
will  make  or  break  your  receiving  set 
as  far  as  good  results  are  concerned? 

Give  your  set  a  fair  chance  to  bring 
in  the  distant  programs.  Resolve  now 
that  a  good  set  deserves  good  tubes 
and  decide  on  MAGNATRONS.  The 
results  will  pleasantly  surprise  you. 

MAGNATRONS  know  no  superiors. 
And  yet  the  MAGNATRON  DC- 
201  A,  the  MAGNATRON  DC- 199 
and  the  MAGNATRON  DC-199  with 
the  large  base  sell  for  only  $3  each,  at 
your  dealer's. 

CONNEWAY  ELECT.  LABS.,  MFGS. 

New  York  City 


The  Radio  Age  Annual  for  1924 ! 

ONLY  A  FEW  LEFT  AT  50c  EACH 

If  you  have  not  bought  your  copy  of  the  famous 
RADIO  AGE  ANNUAL  for  1924,  you  may  get  one 
at  a  special  price  of  50  cents  by  filling  in  the  coupon 
below  and  sending  it  with  stamps,  money  order  or 
draft,  at  once.  The  supply  is  nearly  exhausted,  and 
no  more  will  be  printed,  so  ACT  NOW! 

1924  ANNUAL  COUPON 
Radio  Age,  Inc., 

500  N.  Dearborn  St., 

Chicago,  111. 
Gentlemen:     Please  find  enclosed  50  cents,  for  which  you  may  send  me  a 
copy  of  the  RADIO  AGE  ANNUAL  for  1924,  in  accordance  with  your  special 
price  offer  for  April. 
Name - = -= - - ----- 


Address.- 
City._ 

4-25 


.State.. 


The  Magazine  of  the  Hour 

How  to  Regulate  Your 
Filament  Energy 

(Continued  from  page  17) 

should  include  some  means  of  knowing 
the  condition  of  the  several  batteries 
supplying  the  energy  to  the  set.  Nothing 
is  so  exasperating  as  to  "shoot  trouble" 
on  a  set  and  find  later  that  the  batteries 
are  low;  it  is  like  looking  for  engine  trouble 
and  finding  the  gas  tank  empty.  Conse- 
quently, the  logical  thing  to  do  is  to  have 
an  indicator  of  the  battery  condition  on 
the  panel.  Since  there  are  two  or  three 
sets  of  batteries  in  use,  a  multiple  reading 
voltmeter  with  scales  for  the  "A"  battery, 
detector  "B"  and  amplifier  "B"  batteries 
is  desirable.  Such  an  instrument  with  a 
self-contained  switch  is  shown.  Much 
trouble  due  to  lack  of  knowledge  of  the 
condition  of  the  batteries  may  be  avoided 
if  a  voltmeter  of  this  type  is  mounted 
directly  on  the  panel  of  the  set!  Being 
convenient,  it  becomes  second  nature  to 
check  the  batteries  each  time  the  set  is 
used  and  if  low,  they  can  be  replaced  or 
recharged  before  failing  entirely. 

Watch  the  Oscillator 

OXE  source  of  considerable  trouble  in 
many  super-heterodynes  is  the  abso- 
lute blanketing  of  some  of  the  weak 
incoming  signals  by  a  too  powerful  oscil-  - 
lator.  In  general,  oscillators  are  run  at 
far  too  high  a  plate  voltage  and  the  coup- 
ling between  them  and  the  tuned  input 
circuit  to  the  first  detector  is  too  great. 
Many  good  super-heterodynes  have  been 
built  with  no  other  arrangement  for  the 
pickup  of  oscillating  energy  than  the 
wiring  of  the  set  itself.  In  the  helix 
of  the  oscillator  there  is  a  current  thou- 
sands and  perhaps  millions  of  times 
stronger  than  that  in  the  input  circuit, 
due  to  the  incoming  signal,  and  we  only 
need  to  pick  up  a  very  little  bit  of  the 
energy  of  the  oscillator  to  give  us  proper 
heterodyne  action  for  passing  an  inter- 
mediate  frequency   on   to  the   amplifier. 

Many  prominent  experimenters  and 
builders  of  de  luxe'  super-heterodynes 
have  recognized  this  fact,  and  are  equip- 
ping such  sets  with  a  current  squared 
galvanometer  in  the  oscillating  circuit, 
which  shows  the  relative  amount  of 
energy  with  different  values  of  battery, 
etc. 

According  to  theory,  every  signal  will 
be  found  to  have  a  best  value  of  oscillator 
energy  with  w-hich  it  will  give  the  best 
response,  and  by  using  an  instrument 
to  actually  read  the  energy  in  the  oscillat- 
ing circuit,  this  energy  can  be  varied  with 
perfect  control  and  results  can  be  dupli- 
cated because  the  instrument  is  available 
to  read  this  energy.  As  to  methods  of 
control  of  the  oscillator  energy,  a  separate 
filament  rheostat  on  the  oscillator  tube, 
or  varying  the  "B"  battery  voltage,  or 
both  should  give  satisfactory  control. 

Thus  the  complicated  set  becomes 
responsive  to  control,  energy  is  conserved, 
replacements  made  when  necessary  and 
operation  becomes  far  more  exact  and 
reliable.  *   • 


*      Tested  and  Approved   bu   RADIO   AGE     * 


RADIO  AGE  for  April,   1925 


The  Magazine  of  the  Hour 


55 


Mr.  Manufacturer 

Would  you  write  100  letters 

to  100  people 

to  reach  just  two  men? 

Then,  before  you  invest  your  advertising  dollars — THINK! 


This  Association 
is  comprised  of 
the  leading  Ra- 
dio Magazines. 


An  analysis  shows  that  publications  of  general  circulation, 
newspapers  and  magazines,  devote  less  than  2%  of  their 
reading  columns  to  Radio — proving  that  in  the  opinion  of 
their  own  Editors  less  than  2%  of  their  readers  are  inter- 
ested in  Radio.  In  fact,  many  general  publications  carry  no 
Radio  editorial  matter.  Therefore — 98%  of  your  investment 
is  lost! 


On  the  contrary,  the  Radio  magazine  offers  100%  Radio 
editorial — attracts  100%  potential  buyers. 

Spend  your  advertising  appropriation  in  Radio  Magazines. 
Be  sure  of  the  greatest  possible  return  on  your  advertising 
dollar. 

Radio  Magazine  Publishers  Association,  Inc. 

R.\DI0  AGE  is  a  member  of  the  Radio  Magazine  Publishers  Association,  Inc. 


56 


RADIO  AGE  for  April,,  1925 


The  Magazine  of  the  Hour 


You  will  never  know  the  thrills 
of  radio  until  you  own  a 


ffi 


■JUPPE. 


The  Greatest  Value  ever 
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Tl  ^  readers  wish  to  show  their 
r^  approval  of  the  stand  taken 
by  RADIO  AGE  against  the 
Radio  Corporation  of  America,  they 
can  do  it  in  the  most  practical  way 
by  sending  $2.50  for  a  year's  sub- 
scription to  our  magazine,  or  if  they 
are  already  subscribers,  urge  a  friend 
to  subscribe.  We  believe  the  fans 
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Inc., 500  N.Dearborn  St., Chicago,  111. 


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lOrUl  Union  Avenue.   Dept.  444 CHICAGO 


Giving  the  Farmers  a 
Square  Deal 

(  Continued  from  page  30) 
From  Dubuque  County,  Iowa,  comes 
a  comment  from  H.  F.  Hefferman.  It 
shows  the  value  of  the  radio  in  building 
up  a  co-operative  community  spirit  which 
is  doing  much  to  put  agriculture  on  a 
profitable   business   basis   in    America. 

"We  have  a  radio  in  a  small  country 
store  and  post  office  here,"- he  says. 
"And  it  has  come  to  my  notice  that 
farmers  are  taking  advantage  of  the 
service  that  we  post  in  a  great  many 
ways.  There  is  hardly  a  day  that  we  do 
not  get  phone  calls  from  the  country  on 
the  hog  and  cattle  markets.  Farmers 
like  the  leftover  each  day  as  it  gives  them 
a  good  chance  to  figure  the  next  day's 
market." 

In  addition  to  the  influence  of  WLS 
on  the  strings  of  the  farmer's  money  bags, 
this  radio  service  is  also  putting  money 
indirectly  in  the  producer's  pockets  by 
giving  talks  on  various  phases  and  im- 
proved methods  of  agriculture.  Dan 
Meade,  near  Harvard,  Illinois,  listened 
in  on  a  talk  on  hays  last  spring,  and  as  a 
result  he  planted  soy  beans  along  with 
his  red  clover  and  alfalfa.  Later  he 
found  that  when  he  put  the  soy  bean  hay, 
loaded  with  rich  soy  beans,  into  his  dairy 
ration,  the  cows  responded  with  increased 
milk  production.  Mr.  Meade  wrote  in  to 
W  L  S,  asking  that  the  food  value  of  soy 
bean  hay  as  compared  with  the  two  other 
hays  be  broadcast  over  the  radio.  In  a 
few  days  he  listened  in  to  a  scientific 
statement  on  the  feed  value  of  soy  bean 
hay.  Thousands  of  farmers  over  America 
listened  in  at  the  same  time  with  Mr. 
Meade,  and  they  too,  acquired  a  new 
dea  or  a  new  standard  for  a  more  scien- 
tific system  of  agriculture. 

"RFD"  Programs  Started 

WITH  the  idea  of  drawing  the  agri- 
cultural men  of  the  nation  into  a 
closer  union  for  the  benefit  of  the  coun- 
try, WLS  recently  organized  a  national 
farm  radio  club  called  the  Radio  Farmer's 
Democracy — "RFD."  What  the  men 
to  whom  it  is  directed  think  of  the 
"RFD"  is  told  in  a  letter  from  Lawrence 
G.  Kiesling,  who  has  a  farm  near  Mason 
City,  Illinois:  "We  surely  enjoy  your 
RFD  program  over  our  radio.  I  am  at 
the  radio  every  noon  hour  and  I  would 
rather  miss  my  dinner  than  miss  your 
noon-day  programs.  I  like  to  eat  pretty 
well,  too!" 

Since  farmers  must  eat,  and  farm  wives 
must  cook,  as  well  as  direct  certain  other 
important  activities  about  the  farm  busi- 
ness, WLS  has  instituted  the  Home- 
maker's  Hour.  From  3:45  to  4:45,  five 
days  a  week  from  Monday  to  Friday, 
millions  of  farm  women  over  the  country 
listen  in  on  talks  by  recognized  home 
economics  specialists,  poultry  experts, 
designers,  club  women  and  other  special- 
ists in  all  kinds  of  women's  activities. 

Other  programs  of  WLS  reflect  the 
play  side  of  life. 

Everybody  everywhere  looks  to  the 
Saturday  night  barn  dances  held  in 
thousands  of  communities  regularly, 
with  the  orchestra  broadcasting  from 
WLS  in   Chicago. 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Have  You  Met  the  Latest 
Radio  Age  Stars? 

(  Continued  from  page  33) 

He  will  share  honors  with  Eddie  Borroff 
in  announcing  RADIO  AGE  programs 
from  the  Congress  Hotel  Studio  of  KYW 
the  first  Saturday  in  every  month,  begin- 
ning at  midnight.  "Sen"  also  has  a  few 
entertaining  tricks  which  he  performs 
before  the   "Mike." 

It  will  interest  many  followers  of 
RADIO  AGE  programs  to  know  that 
Banks  Kennedy,  organist  and  concert 
pianist  at  Balaban  &  Katz'  Tivoli 
Theater,  Chicago,  is  now  a  regular  mem- 
ber of  this  magazine's  studio  staff. 

He  appears  at  WEBH  every  Tuesday, 
Thursday  and  Saturday  evening  after 
11  o'clock,  and  at  KYW  once  a  month, 
exclusively  under  the  auspices  of  RADIO 
AGE.  Banks  has  several  new  numbers 
that  will  amuse  you.  Listen  in  and  write 
him  or  RADIO  AGE  on  how  you  like  his 
original    compositions. 

Banks,  you  will  remember,  originated 
the  famous  "Arrange  It"  song. 

Lee  Sims  Joins  KYW  Staff 

THE  KYW  staff,  at  Chicago,  has 
another  member  in  its  fold.  Lee  Sims, 
the  jolly  tickler  of  the  keys,  formerly 
musical  director  of  WTAS,  is  now  the 
presiding  factor  at  the  piano  at  all  KYW 
programs  .in  Hearst  Square  studio.  He 
made  his  debut  with  that  station  on 
Tuesday,  February  10,  amidst  an  aval- 
anche of  greetings,  verbal,  telephonic  and 
telegraphic. 

Since  his  advent  into  the  radio  world, 
in  February,  1924,  when  C.  E.  Erbstein, 
owner  of  station  WTAS,  signed  up  Lee 
as  his  musical  director,  his  medley  and 
jazz  renditions  have  placed  Lee  in  the 
fore  among  radio  pianists,  and  he  has 
often  been  ascribed  as  the  "King  of  them 
all."  As  a  symbol  of  his  popularity,  his 
first  appearance  on  a  KYW  program  was 
the  signal  for  a  rush  of  telegrams  from 
far  and  near;  telegrams  sent  in  by  regular 
followers  of  KYW,  welcoming  Lee  Sims 
into  the  big  family  and  asking  him  to 
dish  out  some  of  his  novel  pianologues. 
The  radio  artist  does  not  hear  applause, 
but  a  greeting  of  this  kind  is  always  a 
thriller  and  is  the  only  token  to  indicate 
an  enthused  world  of  listeners-in. 

RADIO  AGE'S  program  over  KYW, 
on  February  7,  which  was  broadcast 
from  the  "Little  Red  Studio"  atop  the 
Congress  Hotel,  included  Lee  Sims  in  its 
repertoire.  Seated  at  the  piano  he  very 
forcefully  made  the  "piano  like  it."  He 
will  be  heard  again  on  RADIO  AGE'S 
monthly  donations  to  ether  entertain- 
ment. This  will  give  the  radio  night- 
prowlers,  whose  tentacles  reach  to  KYW, 
an  opportunity  to  listen  in  on  medleys 
unheard  before. 


RADIO   AGE'S  SCHEDULE 
ON  THE  AIR 

WEBH  (370)  11  to  12  p.  m.,  Tuesday, 
March  24 — Popular  and  semi-classical 
program. 

KYW  (535)  11:45  p.  m.  to  1  a.  m. 
Saturday,  April  4 — "Congress  Hotel 
Jazz  Carnival." 

WTAY  (283)  Every  Wednesday,  9:45 
p.  m. — Technical  talk  by  RADIO  AGE 
staff  member. 


General  Theory  of  the  Toro-Tran 

Figure  1  shows  how  the  field  of  the  ordi- 
nary coil  extends  into  space  and  increases 
losses  due  to  stray  field.  Fifiure  2  shows  a 
donble  series"  winding  which  restricts  the 
field  somewhat.  Figure  3  shows  a  "four 
series"  winding  and  the  fieldali]  ater. 
In  Figure  4  [the  Toro-Tran]  the  field  is  entire- 
"lclosed  and  the  losses  due  to  stray  fields 


introduced  from  the  aerial  c 

i  balanced  out  at   "V'bythert 
rity  of    the   winding.   This 


the  tube-   ._ 

versed  polsi 

undesirable    signals   while   the"    concentrated 

internal  field  builds  up  the  tuned  signal.  Hence 

maximum  distance  and  selectivity. 

-and  now  the  TORO-TRAN! 

CARDWELL,  whose  pioneer  "low-loss"  condenser  established  new 
standards  of  radio  efficiency,  is  now  introducing  the  Toro-Tran* —  the 
ideal  balanced  coupling  inductance  for  all  radio  frequency  work.         ^1* 

*  TRADE  MARK  ^F* 

Registry  applied  for 

The  Toro-Tran  eliminates  signal  energy  power  machinery,  elevators,   door  bells, 

picked  up  by  ordinary  coils  from  nearby  arc  stations,  etc. 

stations.      It   eliminates   magnetic  feed-  The  Toro-Tran  winding  confines  the 

back  in  multi-stage  radio  frequency  cir-  field  to  the  inside  of  the   coil,   a  small 

cuits,   thus   removing   the   most    active  area,  and  thus  avoids  one  of  the  greatest 

factor  in  causing  howling  and  distortion  causes  of  loss  known  to  radio  receivers  — 

and  thereby   increasing   selectivity   and  that  of  stray  magnetic  fields  which  result  in 

distance.    It  rejects  almost  entirely  the  the  absorption  of  signal  energy  and  reduce 

interference  effects  caused  by  electrical  theefficiencyofthcreceivertremendously. 

Note  these  unusual  advantages  in  assembly  and  operation 

1.  Compactness.  The  coils  do  4.  Low  distributed  capacity  est  loss  factors  in  the  ordinary 
not  require  spacing  or  angular  due  to  air  spacing  of  each  wind-  circuit  and  is  not  remedied  by 
mounting.  They  occupy  less  ing  and  to  low  voltage-drop  "skeleton"  or  so-called  "low- 
space  than  your  condensers.  per  turn  of  small  diameter  wire.  loss"  windings. 

2.  Permit    exact    nullification  ,_     .  ,.  ,7.  Ease   of  neutralizing   oscil- 
c       a.   t,           j      *.                      -*.          5.  Maximum      coupling      and        ,    .-         ,  .    .  ..     , 
for   tube    and    stray    capacity        ,  .   ,          .        ,       ,           .                      lation  due  to  tube  capacity  by 

-,_,                              i          -j-  high  ratio  of  voltage  increase  c         ,    , .                V.     , 

without  guess  work  or  tedious  ,  **                       ^     ^  f  _.  ,,      .  ,  means      of     rotating      control 

due  to  concentrated  field  with  ,  -  ,                              .,.    .           ,, 

testing.                                                                .     .  which  anyone  can      balance. 

_,        ,                 ._,,,..  zero  leakage.  . 

3.  Closed  magnetic  field  ehmi-  8.  Low  capacity  between  pn- 
nates  magnetic  feed-back  in  6.  Absence  of  all  supporting  mary  and  secondary,  affording 
tuned  radio  frequency  am-  insulation  in  the  field  of  the  maximum  transfer  of  energy 
plifiers.  coil.    This  is  one  of  the  great-  to  succeeding  grid-circuit. 

The  Toro-Tran  has  a  lower  "circuit  re-  Trans.    You  will  be  astonished  with  the 

sistance"  (i.  e.  effective  resistance  as  as-  results.  Most  .00035  mfd.  variable  con- 

sembled  in  a  set  and  not  as  isolated  in  densers  will  tune  them,  but  by  using  Card- 

the  laboratory  for  theoretical  measure-  well     Condensers     you     get     maximum 

ments)  than  any  inter-stage  tuned  trans-  efficiency. 

former  made  and  has  a  correspondingly  0r(Jer  from  deaIer  or  direct 

higher  amplification  factor,  its  ratio  ex-  CARDWELL    TOro-TRAN    WITH 
ceeding  ten.  BALANCING  POTENTIODON .    $  4.00 

To   appreciate  the  many  remarkable  Cardwell  .00035  Condenser  for  tuning .  .     4. 75 

advantages  of  the  Toro-Tran  write  for  Cardwell  .00035  Vernier  Condenser 6.25 

our  two  free  booklets:  "The  Torodyne  Cald^°°035.  ^a} . C.°ndens.er.  <?™"    8.00 
Circuit"    and    "The    Most    Interesting  Cardwell  .00035  Triple  Condenser  (three- 
Radio  Frequency  Transformer  Ever  In-  in-one) 12 .00 

Vented."  Cardwell  Audio-Trans  (compound  audio 

transformers) 10  .  00 

Toro-Trans   are   ready    to    mount   in 

any  tuned  radio  frequency  circuit.  Re-  The  Allen  D.  Cardwell  Mfg.  Corp. 
place    your    ordinary    coils   with    Toro-  81  Prospect  Street,  Brooklyn,  N.Y. 


How  Much  Is  Your  Spare  Time  Worth? 

You  can  add  considerably  to  your  income  by  profitably 
applying  yourself  during  your  spare  time.  Hundreds 
of  boys  and  young  men  are  laying  the  foundations  of 
independent  incomes  in  this  way.  If  you  are  inter- 
ested, write  to  the  Circulation  Manager,  Radio  Age,  Inc., 
500  N.  Dearborn  St.,  Chicago,  and  information  will 
be  sent  you  at  once. 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


1    tuned  iaal°  "^advanced  m 
i  tuu      ..  the  niost    .„    It  is  an 

Youwill  k^^  distant  sta- 
1    X  .      _  ,Vvat  b"°B    ■    ,-TSelectthe 

i  tion'ctota  inXs  Apex 

«■£•«£*■  ^Sat  number, 
Vernj«  e^\re_perfcct  wc^ 


_.:.v.  the  Apex  ^  «■    .,  uedwal' 


^ith  the  Apes =      fished  «al. 
H°u6el^et  complete  «xth^ 

plated.  be'';n(,  accessories.  //, 

^AU  Qood  Dealers/ 

Chicago 


on 


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65  Proven  Radio  Axioms 
for  the  Fan 


(Continued  from  page  18) 


36.  Sunlight  cuts  down  the  reception 
distance  by  at  least  one-half  and  some- 
times more. 

37.  Apparatus  with  large  diameter  coils 
is  generally  better  than  that  with  coils 
of  smaller  diameter  but  of  the  same 
inductive  value.  This  applies  to  audio 
frequency  inductances  and  transformers 
as  well  as  to  radio  frequency  types. 

38.  Thick  insulation  on  coiled  wire 
gives  less  loss  through  distributed  capa- 
city than  thin  insulation.  Enameled 
wire  is  not  the  best  for  radio  frequency 
currents  for  this  reason. 

39.  Giving  the  proper  negative  biasing 
voltage  to  a  tube  increases  its  sensitivity 
and  gives  better  tone  value. 

40.  The  proper  bias  on  the  tubes  of  a 
reflex  circuit  will  stop  annoying  audio 
frequency  oscillations  in  the  tubes. 

41.  Regeneration  can  be  controlled 
either  by  the  rheostat  or  by  varying  the 
magnetic  feedback  between  the  tickler 
and  secondary  coil.  By  using  both 
methods  at  one  time,  one  acts  as  a  vernier 
to  the  other  and  better  results  are  had. 

42.  All  detector  tubes  have  a  sharply 
critical  rheostat  position  where  maximum 
reception  is  had.  This  point  varies  with 
the  plate  voltage. 

43.  The  greater  the  plate  voltage  on 
the  detector,  the  greater  the  current  that 
can  be  fed  to  the  filament  without  "spil- 
ling," and  the  louder  will  be  the  signals. 

44.  Increased  volume  due  to  increased 
plate  voltage  is  not  due  directly  to  the 
voltage  but  to  the  fact  that  greater 
filament  emission  can  be  maintained 
without  "spilling"  of  the  tube. 

45.  Increasing  the  plate  voltage  makes 
the  tube  and  reostat  adjustment  more 
critical  and  hence  adds  some  to  the 
selectivity. 

46.  When  the  plate  voltage  is  increased 
the  bias  should  also  be  increased  in  order 
to  reduce  the  demand  for  current  on  the 
"B"  batteries. 

47.  With  plate  voltage  above  67.5 
volts,  most  circuits  become  noisy  with 
the  tubes  now  in  use. 

48.  With  a  plate  voltage  of  from  67.5 
to  90  volts,  the  volume  of  a  detector  is 
increased  on '  local  stations,  but  is  not 
much  greater  than  with  22.5  volts  on 
stations  more  than  50  miles  distant. 

49.  A  soft  detector  tube  cannot  be 
used  with  voltages  greater  than  24  volts. 

50.  The  use  of  a  detector-tube  in  place 
of  a  crystal  in  a  reflex  circuit  is  a  good 
investment.  The  crystal  cannot  amplify 
but  the  tube  will  increase  the  signal 
strength. 

51.  Two  amplifier  tubes  reflexed  with 


a  three  element  detector  tube  will  usually 
give  better  distance  than  three  amplifier 
tubes  reflexed  with  a  crystal  detector. 

52.  For  minimum  battery  consumption 
with  a  given  amplification,  two  tube 
reflex  with  a  regenerative  detector  tube 
in  place  of  a  crystal  detector  is  the  most 
effective. 

53.  The  value  of  the  by-pass  conden- 
sers in  a  reflex  circuit  depends  upon  the 
make  of  audio  transformers  used.  The 
impedance  of  some  transformers  is  so 
low  and  the  distributed  capacity  of  the 
windings  is  so  great  that  by-pass  con- 
densers (fixed)  are  sometimes  best  elimi- 
nated. 

54.  Reflex  circuits  with  tuned  radio 
frequency  transformers  are  far  the  best. 

55.  Dry  cell  tubes  are  not  such  good 
amplifiers  as  power  tubes  designed  for 
storage  cells,  and  their  effectiveness  varies 
roughly  as  the  filament  voltage.  A  3.0 
volt  tube  is  better  than  a  1.5  volt  tube, 
and  a  5.0  volt  tube  is  better  than  either 
of  them.     Maximum  with  8.0  volt  (202). 

56.  Biasing  is  most  effective  above  45 
volts  plate  current. 

57.  Most  detector  tubes  are  sensitive 
to  the  resistance  of  the  grid  leak;  hence 
this  should  be  variable. 

58.  Grid  leaks  should  be  adjusted  on 
distant  stations  or  weak  signals  for  DX 
work,  and  require  higher  resistance  than 
local. 

59.  For  local  reception,  grid  leaks  are 
adjusted  for  maximum  volume  and 
freedom  from  noise. 

60.  Unbalanced  circuits  of  the  Ultra- 
audion  type  give  the  best  results  with 
variable  grid  condensers. 

61.  Aperiodic  type  couplers  and  trans- 
formers give  the  greatest  selectivity  with 
a  minimum  number  of  tuning  controls. 

62.  A  crystal  detector  circuit  is  less 
selective  than  a  tube  circuit  of  same  type 
and  with  the  same  tuning  units. 

63.  Detector  crystals  may  be  divided 
into  two  classes:  (1)  Those  crystals 
which  are  sensitive  on  weak  signals  and 
distance,  and  (2)  Those  which  give  the 
greatest  volume  on  strong  local  stations. 
The  former  are  to  be  used  with  simple 
crystal  sets,  while  the  latter  are  best  for 
reflex  detectors. 

64.  Galena  is  probably  about  the  best 
crystal  for  crystal  detector  sets,  but 
silicon,  perikon,  and  the  numerous  trade- 
marked  synthetic  crystals  are  best  for 
reflex  detectors. 

65.  Resistance  has  nothing  to  do 
directly  with  the  sensitivity  of  phones. 
A  headset  may  have  a  high  resistance 
and  yet  not  be  sensitive. 


May  is  the  month  that  you  start  building  that  portable  set  for 
your  summer  trips.  In  this  issue  RADIO  AGE  begins  the  publica- 
tion of  a  series  of  portable  receiver  articles,  and  in  the  next  issue 
this  subject  will  be  continued  on  a  larger  scale  than  ever.  The 
outdoor  radio  fan  should  by  all  means  get  this  "Portable"  issue  of 
RADIO  AGE,  "The  Magazine  with  Blueprints." 

*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


59 


Letters  of  a  Radio  Fan 
to  His  Son 

(Continued  from  page  20) 
inductances     and     condensers     are     con- 
cerned,   1923   is   the   early   stone   age   of 
radio,  and  that's  pretty  rocky. 

Now,  there  are  a  few  general  principles 
about  inductances  which  the  old  man 
can  hand  on  to  you  as  the  result  of  con- 
versations with  such  scientifically  minded 
inventors  as  Cari  Pfanstiehl,  etc. 

He  once  showed  me  the  several  ways 
coils  are  wound  and  the  consequences 
in  each  case. 

Fig.  1.     Solenoid  Winding 

Here  is  an  old-style  solenoid  winding 
where  the  insulated  wires  are  placed 
side  by  side  and  in  contact.  In  the  first 
place,  your  solenoid  or  drum  is  a  beau- 
tiful absorber  of  the  energy  which  is 
thrown  out  from  the  coil.  That  is  loss 
number  one.  Next,  the  wires,  being 
parallel  and  close,  act  like  condensers 
and  produce  what  is  called  distributed 
capacity.  This  acts  like  a  load  across 
the  coil  and  constitutes  loss  number  two. 
And  worst  of  all,  such  a  coil  disperses 
energy  in  the  form  of  a  magnetic  field 
all  around  the  set,  because  the  spread- 
cut  position  of  the  wires  occasions  a 
spread-out  field.  You  know  that  when 
a  magnetic  field  cuts  across  a  wire  or 
metal  surface  it  sets  up  a  current  there. 
Well,  this  not  only  constitutes  loss  num- 
ber three,  but  has  the  effect  of  causing 
howls  and  whistles  in  your  set.  There- 
fore, this  old  Rameses  winding  isn't 
low  loss.    Avoid  it. 

Fig.   2.     Spiderweb   of  the   old   style 

You  can  wind  the  wires  straight  up 
and  down,asshownin  my  second  masterly 
drawing,  on  a  "spider"  or  frame.  Every- 
thing I  said  about  the  first  winding 
applies  against  waste  of  energy  by 
dielectric  absorption,  distributed  ca- 
pacity losses  and  finally  waste  through 
producing  a  spread-out  field  of  force 
which,  as  explained,  puts  rats  into  your 
radio. 

Fig.  3.     Honeycomb  Winding 

Thirdly,  you  have  the  famous  old 
honey-comb  winding,  which  isn't  so  bad. 
It  does  have  a  core  which  absorbs  energy, 
but  it  gives  practically  no  distributed 
capacity  loss.  Originally-  designed  for 
high  wavelengths,  its  cross  section  was 
square  and  it  did  not  give  a  dispersed 
field.  When  these  coils  were  adapted 
to  the  DX  wavelengths  instead  of  to 
the  original  long  waves,  the  coil  was 
cut  down,  but  the  width  was  left  the 
same.  The  result  is  that  you  have  a 
spread-out  winding,  wnich  disperses  the 
magnetic  field  around  the  set.  This 
gives  you  those  cute  little  cat  calls  which 
set  your  teeth  on  edge. 

Fig.  4.     The  Stagger-wound  Coil 

TTERE  is  a  self-supporting  stagger 
-*--*-  wound  coil  which  has  none  of  the 
disadvantages  of  the  three  others.  There 
is  no  dielectric  in  the  field  to  absorb  the 
energy.  The  wires  are  surrounded  by 
air  everywhere,  except  at  a  few  points, 
and  therefore  the  distributed  capacity 
is  nil.  Naturally,  the  shape  of  the  coil 
(Turn  to  next  page,  column  2) 


Dont 
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iffn- 

Once  you  have  marked  your  favorite 
stations  on  the  Ultra  Verner  silvered 
dial,  all  you  needis  your  radio  program. 
Make  your  evening's  selection.  Forget 
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The  Ultra-Vernier  indicator  points  in- 
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Single  control  operates  vernier  for 
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RADIO  AGE  for  April,   1925 


The  Magazine  of  the  Hour 


Sensations  of  the  Season! 


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(  Continued  from  preceding  page) 
is  such  as  to  make  a  flat  magnetic  field 
which  does  not  spread  out  and  stir  up 
howls  and  whistles  in  the  receiver. 
Therefore,  this  is  a  truly  low  loss  coil. 
Some  of  these  low-loss  windings  do 
not  use  self-supporting  cement.  This 
gains  the  advantage  of  avoiding  a  slight 
waste  of  energy  by  absorption.  But  a 
good  radio  stiffener  made  of  cellulose 
proves  in  the  laboratory  to  give  prac- 
tically no  absorption 
loss,  and  further- 
more it  hermetically 
seals  the  wire  and 
prevents  losses  due 
to  moisture  effects. 

You  can  find  a  wind- 
ing of  this  type  in  a  3- 
circuit  tuner,  shown  at 
the  left.  It  comprises 
a  primary  for  the  an- 
tenna circuit,  a  sec- 
ondary for  the  grid  circuit,  and  a  tickler 
for  the  plate  circuit.  This  is  the  low 
loss  inductance  for  your  first  regenerative 
set.  A  unit  like  this  will  prevent  radia- 
tion; in  other  words  will  prevent  your 
feeding-back  energy  into  your  antenna 
and  broadcasting  howls  and  squeals 
all  over  the  neighborhood. 

In  this  way  you  solve  one  of  the  dis- 
advantages of  regenerative  sets.  The 
means  by  which  you  do  so  is  by  having 
a  separate  primary  (or  antenna  winding) 
in  your  unit.  This  arrangement  also 
increases  selectivity  greatly  and  helps 
solve  the  second  disadvantage  of  the 
regenerative  circuit. 

I  am  enclosing  some  more  money  and 
want  you  to  buy  real  apparatus  this 
time,  as  your  expenses  have  been  very 
heavy  this  month. 

Your    patient    and    affectionate 

"Dad." 


Eby  Cuts  Prices  on  Ensign  Posts 

When  the  radio  business  first  started 
about  five  years  ago  there  were  very  few 
manufacturers  who  weft  far  sighted  and 
courageous  enough  to  build  quality 
products.  Many  firms  were  eager  to  sell 
large  quantities  of  their  goods  at  the 
very  beginning,  but  owing  to  many 
firms  entering  the  manufacturing  field, 
they  were  not  able  to  secure  the  volume 
of  business  at  prices  which  were  necessary 
for  them  to  ask.  Therefore,  many  manu- 
facturers cheapened  their  products  and 
began  to  compete  on  a  strictly  price 
basis. 

Others,  believing  in  the  future  of  the 
radio  industry  and  anticipating  the  pre- 
sent demand  for  quality  merchandise, 
stuck  to  their  price  guns.  The  result  of 
this  policy  is  now  reflected  in  an  inter- 
esting reversal  of  the  whole  situation. 
The  manufacturers  of  quality  products, 
on  account  of  the  large  volume  which 
they  have  inevitably  built  up,  are  now  in 
a  position  to  offer  their  products  at  a 
price  at  least  equal  to  and  in  some  cases 
below,  the  price  of  inferior  goods. 

The  H.  H.  Eby  Mfg.  Co.  were  among 
the  first  to  make  an  insulated  Binding  Post 
with  a  knob  or  top  which  would  not  come 
off.  This  design  of  post  made  it  impos- 
sible to  either  lose  the  tops  or  make  wrong 
connections.  They  were  also  the  first 
concern  to  conveniently  package  their 
complete  line  of  posts. 

They  have  consistently  maintained  the 
high  quality  of  their  product  and  at  the 

*     Tested  and  Approved  by  RADIO  AGE     * 


New  Quarters  for  Station 

wcco 

TV/TINNEAPOLIS,  Minn.— Construc- 
-L»  J-  tion  of  a  building  has  begun  on  top 
of  the  new  Nicollet  Hotel  to  house  the 
new  broadcasting  studio  for  the  Gold 
Medal  Station,  Saint  Paul — Minneapolis, 
WCCO.  The  owners  of  the  station  an- 
nounced that  this  studio  will  be  completed 
late  in  March,  simultaneously  with  the 
completion  of  the  new  5,000  watt  super- 
power broadcasting  station  which  is 
being  constructed  18  miles  northwest  of 
Saint  Paul  and  Minneapolis. 

Minneapolis  executive  offices  of  WCCO 
will  be  opened  at  the  same  time  on  the 
Twelfth  Floor  of  the  new  Nicollet. 

A  one  story  building,  constructed  on 
the  roof  of  the  Nicollet  Hotel  between  the 
penthouses  and  on  its  two  wings,  will  be 
used  to  house  the  studios,  and  studios 
themselves  will  be  of  a  design  unusual 
among  American  broadcast  stations. 

Similar  studios  are  to  be  installed  soon 
at  a  new  location  in  St.  Paul,  officers  an- 
nounced, in  a  place  to  be  selected  by 
Foster  Hannaford,  Saint  Paul  member  of 
the  station's  Board  of  Control. 

Studios  will  be  entirely  soundproof  and 
literally  will  be  "hung  in  the  air."  They 
will  be  built  on  a  three  inch  bed  of  cork, 
with  double  walls  throughout  and  felt 
padding  between  the  walls,  while  the  ceil- 
ing will  be  suspended  four  feet  below  the 
roof  and  the  floor  will  be  separated  from 
the  hotel  proper  by  a  four  foot  "dead  air" 
space. 

Ceiling  and  walls,  extending  downward 
for  four  feet,  will  be  insulated  with  felt, 
covered  with  strips  of  cloth,  and  the 
remaining  ten  feet  of  the  walls  will  be 
covered  with  heavy  curtians.  Windows 
will  consist  of  double  panels  of  glass,  set 
in  felt.  Studios  will  be  venitlated  by  a 
noiseless   artificial   ventilation   system. 

The  floor  space  will  be  charted,  with 
each  space  numbered.  Broadcasters  will 
be  tested,  and  floor  space  numbers  as- 
signed according  to  the  timber  of  their 
voice. 

Entrance  to  the  studios  will  be  gained 
by  a  stairway  from  the  12th  floor  corridor. 
An  electric  hoist  has  been  installed  and 
will  be  used  to  lift  three  23^  ton  steel 
girders,  pianos  for  the  new  studios,  and 
other  material  and  equipment. 

Cost  of  erecting  the  Minneapolis  and 
St.  Paul  studios  will  be  met  by  the  Wash- 
burn Crosby  Company  under  their  agree- 
ment with  the  Minneapolis  Civic  and 
Commerce  Association  and  St.  Paul 
Association,  by  which  Minneapolis  busi- 
ness men  pledged  $30,000  annually  for 
three  years,  and  St.  Paul  firms  $20,000 
annually  toward  an  annual  operating 
budget    of    $100,000. 

present  time  nearly  500  jobbers  handle 
and  catalog  them.  They  are  also  stan- 
dard equipment  with  nearly  240  manu- 
facturers of  radio  sets,  electrical  instru- 
ments and  appliances.  The  large  volume 
of  business  which  they  have  succeeded  in 
building  up  together  with  their  modern 
methods  of  manufacture  is  offered  as  an 
explanation  of  their  recent  announcement 
of  a  price  reduction  on  their  popular 
Ensign  insulated  posts,  formerly  listing 
at  20c  and  now  listing  at  15c. 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


61 


"B"  Voltage  from  an  A.C. 
Rectifying  System 

(Continued  from  page  12) 
Passing  now  to  receiving  sets  requiring 
more  than  three  and  up  to  five  tubes, 
the  rectifier  system  may  be  increased  in 
power  in  a  simple  manner.  Fig.  3  is 
practically  the  same  in  principle,  with  the 
exception  that  two  input  transformers 
and  two  rectifier  tubes  are  adopted.  In 
Fig.  2  we  rectified  only  one  half  of  the 
60  cycle  supply,  since  current  in  the 
reverse  direction  simply  could  not  pass 
and  therefore  had  no  effect.  But  in  Fig. 
3  we  take  advantage  of  this  half  of  the 
cycle  that  is  not  used  in  Fig.  2.  Another 
transformer  and  tube  is  rigged  up  to 
function  when  the  current  is  in  one  direc- 
tion, while  the  other  tube  operates  when 
it  flows  in  the  other.  It's  like  a  push-pull 
amplifier,  where  one  tube  works  while  the 
other  one  rests,  and  vice  versa. 

Transformer  Connections 

IT  IS  very  important  to  observe  the 
exact  connections  of  the  two  input 
transformers.  These  must  be  of  the  same 
type  and  make  and  connected  with  their 
primary  windings  in  parallel,  but  with 
their  secondaries  in  series.  In  case  one 
of  the  secondary  windings  should  be 
reversed  in  wiring,  the  tubes  would  then 
operate  both  at  once  instead  of  alternate- 
ly. A  push-pull  input  transformer  could 
also  be  used,  but  it  has  the  disadvantage 
of  supplying  a  lower  voltage  and  is  there- 
fore not  quite  as  satisfactory.  The  same 
type  of  bell  transformer  is  employed  as 
previously  and  the  filter  system  is  like- 
wise the  same. 

Both  tubes  should  be  the  same  in  am- 
plifying characteristics  to  operate  with 
uniformity.  The  cost  of  operating 
either  of  these  "B"  voltage  rectifier  units 
is  so  very  slight  as  to  be  negligible. 

The  unit  with  two  tubes  may  be  run 
for  ten  hours  at  an  expense  of  less  than 
one  tenth  of  a  cent  for  both  illumination 
and  the  supply  of  "B"  voltage!  And 
coupled  with  its  fool-proof  qualities  and 
its  unfailing  reliability,  the  A.  C.  rectifier 
system  bids  fair  to  gain  wide-spread 
recognition. 


WLS  To  Build  New  Radio 
Station 

Erection  of  a  new  5000-watt  super- 
power radio  broadcasting  station,  to  re- 
place the  500-watt  equipment  now  in 
use  by  WLS,  Chicago,  was  announced 
recently  by  Charles  M.  Kittle,  Presi- 
dent of  Sears,  Roebuck  and  Company. 
The  new  station  is  to  be  built  in  the  open 
country  to  avoid  interference  with  other 
Chicago  broadcasters,  but  the  exact  loca- 
tion of  the  antennae  has  not  been  decided. 
The  sending  towers  will  probably  be 
erected  within  50  miles  of  Chicago. 

Service  from  the  new  station  will  start 
within  three  months,  according  to  the 
present  plans  of  Edgar  L.  Bill,  director 
of  WLS.  At  the  time  of  inaugurating 
the  new  plant,  it  is  hoped  to  have  the 
twin  studios  now  in  preparation  in  the 
downtown  district  of  Chicago  ready  for 
use.  The  new  station  will  reach  out 
two  and  one-half  times  the  distance 
touched  now,  and  it  is  expected  that 
every  state  in  the  union  will  be  able  to 
listen  in  on  the  programs  every  day. 


Here's  a  peculiar  fact 

about  radio  insulation 

•jyrATERIAL  that  is  satis- 
A  factory  for  general  elec- 
trical use  often  gives  poor  results 
in  radio-frequency  service.  Ex- 
perience has  shown  that  best 
results  come  with  the  use  of 
material  and  apparatus  designed 
especially  for  radio's  peculiar 
demands.  This  is  particularly 
true  of  insulating  material. 

Radion  is  a  special  material, 
developed  to  order  by  our  engi- 
neers to  meet  the  needs  of  radio. 
For  radio  frequency  insulation 
its  characteristics  are  highest,  as 
shown  by  authoritative  labora- 
tory tests. 

The  use  of  the  most  efficient 
insulation  material  is  important 
not  only  for  panels,  but  also  for 
dials,  sockets,  knobs,  binding 
post  panels,  rotors,  stators,  spa- 
ghetti tubes,  etc.  In  all  these 
there  is  a  Radion  product  of  the 
right  type  and  size  for  your  set. 
Radion  is  also  used  by  leading 
set  manufacturers  who  appre- 
ciate the  superiority  of  "the 
supreme  insulation." 

AMERICAN  HARD  RUBBER  COMPANY 
Dept.  BC1,  11  Mercer  St.,  New  York  City 

Chicago  Office:  Conway  Building 
Pacific  Coast  Agent:    Goodyear  Rubber 
Co.,  San  Francisco— Portland 

Mail  coupon  for  Booklet, 
"Building  Your  Own  Set'' 


Surface  leakage  very  low 
with  Radion  Panels 

The  high-polished,  satin-like 
finish  of  Radion  Panels  prevents 
moisture  from  gathering  to  form 
leakage  paths  and  cause  leakage 
noise.  Surface  leakage  and  dielec- 
tric absorption  are  exceptionally 
low. 

Radion  Panels  resist  warping. 
They  are  easy  to  cut,  drill  and 
saw.  They  do  not  chip.  No 
special  tools  needed.  Eighteen 
stock  sizes,  two  kinds,  Black  and 
Mahoganite. 


* 


Radion  Dials  match 
Radion  Panels  perfect- 
ly and  make  the  ideal 
mounting  for  your  set. 
Radion  Sockets  help  to 
eliminate  c  a'p  a  c  i  t  y 
effects. 


"Radion 

^the  Supreme  Insulation 

MADE  TO  ORDER  FOR  RADIO 
PURPOSES  EXCLUSIVELY 


AMERICAN  HARD  RUBBER  COMPANY, 
Dept.  BC1,  11  Mercer  St.,  New  York  City. 

Please  send  me  your  new  booklet,  "Building 
Your  Own  Set,"  giving  wiring  diagrams,  front 
and  rear  views,  showing  a  new  set  with  slanting 
panel,  sets  with  the  new  Radion  built-in  horn, 
lists  of  parts  and  directions  for  building  the  most 
popular  circuits. 
I  enclose  10  cents. 

Name.. 

Address 


OVERSTOCKED  ON  KITS 


GENUINE  COCKADAY  SUPER-HET-REFLEX... 

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ULTRADYNE,     with    Cabinet 

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WESTERN  ELECTRIC  CONE  TYPE  SPEAKER 

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OSTERMEIER  RADIO  &  ELECTRIC  CO. 

1720   South    Douglas   Ave.  SPRINGFIELD,    ILLINOIS. 


HAVE  YOU  BOUGHT  YOUR  1925  ANNUAL? 

Tested  and  Approved  by  RADIO  AGE     V 


62  RADIO  AGE  jo-  April,  1925 


Free  Booklet 

and  "Hookups" 

Write     (^\W^\    *ee 
Today '  \  ' 


The  Magazine  oj  the  Hour 


* 


Premier 

"Lo  Loss"  Tube  Socket 

Checks  Current  Losses 

What  is  it  that  saps  current  strength?  Insu- 
lation leakage,  poor  contact  and  mutual 
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LOSS  Tube  Socket  is  specially  designed  to 
stop  such  losses.  The  bakelite  cross  section 
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terminals.  All  metallic  parts  are  arranged 
for  minimum  capacity.  Positive  contact  is 
insured  by  cam  action  lock  and  self  cleaning 
action  of  contact  spring  on  tube  prong. 
One  piece  contact  springs  have  twice  ordinary 
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inspection  of  contacts  at  all  times. 
Price  90  cents 
Send  for  Bulletin  No.  94 
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The  Burglars  Laugh  Last  at 
"Honeymoon  Camp" 


(Continued  from  page  22) 


tuned.  Of  course,  there  were  a  good 
many  other  amateurs  in  the  air,  and 
they  were  manifesting  not  a  little  curi- 
osity as  to  the  meaning  of  the  "radio 
tilt"  with  the  burglars. 

"This  is  Billy  Rumford  in  camp, 
Charley,"  the  honeymooner  announced. 
"Tune  down  to  150;  I  want  to  get  away 
from  this  interference  and  talk  to  you." 

"All  right,"  said  Charley.  "Down 
we  go." 

A  few  moments  later  they  were  con- 
versing on  a  wavelength  that  could  not 
possibly  be  received  by  Alice's  brother's 
super-hetrodyne,    tuned   to    162. 

"There  are  burglars  in  Ray  Harrison's 
home,"  Billy  began.  "He's  in  Washing- 
ton now  perfecting  a  patent  on  an  auto- 
matic switch  and  consulting  with  govern- 
ment officials  regarding  some  kind  of 
deal  on  his  invention.  Meanwhile,  the 
very  best  possible  test  of  his  invention 
is  now  taking  place.  He  hooked  it  up 
with  a  burglar  alarm  in  his  home.  The 
burglars  who  entered  the  place  tonight 
threw  the  switch  into  sending  by  open- 
ing a  door  or  window,  and  have  been 
broadcasting,  unwittingly,  their  con- 
versation while  opening  the  safe  and 
taking  out  the  valuables.  The  auto- 
matic switch  works  both  ways. 

"I've  been  talking  to  them  and  I've 
got  them  mystified.  They  don't  know 
whether  to  go  or  leave.  Now,  I  want 
you  to  call  the  police  on  the  telephone 
and  surround  the  house  as  soon  as  pos- 
sible. Meanwhile,  I'll  do  all  I  can  to 
keep  them  there.  Tell  the  police  not  to 
enter  the  house,  but  to  conceal  them- 
selves outside  and  grab  them  when  they 
come  out.  I  may  work  up  some  kind  of 
scheme  to  make  the  capture  easy.  I'll 
call  you  again  in  a  few  minutes  to  learn 
what  success  you've  had.  Keep  on  this 
wave." 

CHAPTER   III. 
Radio  "Raspberry" 

BILLY  now  tuned  back  for  the  home 
of  Alice's  parents  and  received 
speedy  evidence  that  the  burglars  were 
engaged  in  a  lively  discussion  of  the 
radio    mystery. 

"Do  you  know  anything  about  radio, 
Sam?"  was  the  first  utterance  that  came 
clearly  to  the  "ethereal  eavesdroppers." 

"Not  a  thing,  Bimbo,"  Sam  replied. 
"That's  the  reason  I  got  scared  so  stiff." 

"I  don't  know  much  either,"  said 
Bimbo.  "But  I  know  enough  to  be  dead 
sure  there's  a  big  mystery  here.  Some- 
body, I'm  afraid,  knows  we're  in  this 
house." 

"Then  we'd  better  get  out  of  here 
mighty  quick." 

"No,  I  don't  think  we  need  to  be 
scared  right  away.  The  guy  that's  on  to 
us  may  be  a  thousand  miles  from  this 
burg." 

"You  don't  say!" 

"Yes,  I  do.  And  I've  heard  it  said 
some  radio  men  can  pull  off  some  awful 
Tisted  and  Approved  by  RADIO  AGE     * 


stunts  with  their  machines.  I  read 
something  in  a  paper  about  'em  being 
able  to  kill  a  guy  just  like  a  stroke  of 
lightning  a  long  way  off.  It  struck  me 
like  a  fake,  but  this  makes  me  ready  to 
believe   most  anything." 

"Great  guns,  Bimbo!  That  guy  may 
kill  us  right  here." 

"No,  not  here.  It  might  set  the  house 
on  fire.  Let's  wait  here  till  that  radio 
guy  gets  tired  an'  quits.  Then  we  c'n 
sneak  out  an'  skin  off." 

"How  do  you  suppose  he  got  onto  us 
here?  You  don't  think  he  can  see  by 
radio,    do   you?" 

"Hanged  if  I  know.  Biggest  mystery 
ever  struck  me.  I  feel  just  as  if  somebody 
was  lookin'  at  me  right  through  the  dark- 
ness." 

"I'm  feelin'  spooky,  Bim.  Wish  I 
never  come  here.  Let's  look  out  of  the 
windows  an'  see  if  anybody's  stalkin' 
about." 

There  was  silence  in  the  campers'  loud 
speaker  for  a  minute  or  two;  then  the 
awed  conversation  continued; 

"No,  I  don't  see  nobody.      Do  you?" 

"Not  a  sign.  Everything's  as  dead  as 
a  graveyard.  Say,  Sam,  I  wish  I  could 
talk  to  that  guy  in  the  radio;  I'd  try  to 
find  out  what  his  game  is." 

"Talk  to  him,"  said  Billy,  throwing 
over  the  switch  and  then  throwing  it 
back. 

"Hear  that?"  exclaimed  one  of  the 
burglars.  "He  seems  to  hear  everything 
we  say." 

"He  hears  everything  you  say,"  Billy 
echoed  solemnly. 

"And — and — can  you  see  us?"  inquired 
a  voice  that  Billy  took  to  be  Bimbo's. 

"I  don't  need  to  see  you;  I  can  fee/ 
you." 

"Oh-h-h-h!"  screamed  a  duet  of  voices 
in  the  camp  loud  speaker. 

"I  touched  them,  or  they  imagined  I 
did,'  said  Billy  for  the  benefit  of  his  fel- 
low campers. 

"What  do  you  want?"  demanded 
Bimbo,  rather  weakly. 

"An  even  split-up  of  your  swag," 
Billy  replied  with  measured  slowness. 

A  string  of  mild  expletives  met  this 
announcement. 

"You'd  better  be  good  and  come 
across,"  Billy  advised.  "I  can  either  kill 
you  or  hand  you  over  to  the  police.  I 
have  the  power  of  lightning  in  my  hands. 
Don't  try  to  leave  that  place  without  my 
permission." 

"Where  are  you?"  was  the  burglar's 
next  question. 

The  Plot  Thickens 

"T  AM  in  an  automobile,  driving  toward 
J.  Evansviile,  and  have  a  radio  outfit 
sending  and  receiving,  with  me,"  Billy 
replied.  "I  am  a  burglar  myself ;  a  radio 
burglar,  if  you  please,  and  I  want  to 
make  a  bargain  with  you  fellows.  If  we 
can  come  to  an  agreement,  I  won't 
demand  a  share  of  the  swag  you  took 
tonight.     With  my  radio  I  can  test  any 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


63 


house  supplied  with  a  radio  and  find  out 
from  a  safe  distance  if  there  is  anybody 
home  and  if  it  would  be  safe  to  break  in. 
I  was  testing  that  house  among  otheis 
in  Evansville  when  I  overheard  your  con- 
versation. I  probably  would  have  broken 
in  there  myself  if  I  hadn't  found  you 
there.  On  second  thought,  I  don't  be- 
lieve I'll  demand  a  split-up  of  your  swag 
tonight.  You  guys  talk  as  if  you  had  some 
brains,  and  I'd  like  to  form  a  partner- 
ship with  you.  I'll  prepare  the  way  for 
every  job  and  make  sure  that  it  is  safe; 
then  you'll  do  the  work,  and  we'll  split 
even.     How  does  that  strike  you?" 

"Sounds  all  right,"  answered  Bimbo, 
"Where'll  we  meet  you?" 

"You  stav  right  where  you  are.  I'll 
drive  up  to  the  house  in  a  few  minutes. 
You  come  out  with  your  swag,  and  I'll 
drive  you  away  anywhere  you  want  to 
go,  and  then  we'll  talk  business." 

"How  do  you  know  where  we  are? 
How  can  you  find  this  house?"  asked 
Bimbo. 

"Oh  that's  easy.  I've  got  a  radio 
compass,  and  I  can  locate  any  radio 
station  with  that.  Will  you  stay  there 
till  I  arrive?" 

"Yes,  we'll  stay,"  Bimbo  assured. 

Billy  now  tuned  for  Charley  Patterson's 
station  again  and  found  him  waiting  for 
the  call. 

"The  sheriff  and  three  armed  men  are 
here  at  the  house  waiting  for  instructions 
to  move,"  Charley  said.  "We're  all  going 
to  drive  over  -there  in  my  car.  You're 
some  radio  honeymoon  detective,  Billy. 
Unless  there's  a  slip-up  somewhere,  we're 
going  to  make  a  famous  catch." 

"Good!"  exclaimed  Billy. 

Then  he  gave  his  friend  a  hurried  ac- 
count of  what  had  taken  place  since  their 
last  "conference"  by  radio  and  continued: 

"Drive  up  in  front  of  the  house  and 
then  get  out  and  walk  around  the  car. 
I'll  tell  them  that  will  be  a  sign  by  which 
they  will  know  I've  arrived.  Have  the 
sheriff  and  his  men  hidden  in  the  back  of 
the  car,  and  when  the  burglars  come  out 
and  approach  the  machine,  they  can 
shove  their  guns  into  the  faces  of  the 
scamps.  Be  careful  and  don't  get  in  the 
way  of  any  bullets.  You  can't  swallow 
them  the  way  I  did,  you  know." 

"Oh,  I'm  sworn  in  already  as  a.  deputy 
for  this  occasion,"  Charley  replied;  "and 
I'm  likely  to  do  some  shooting  myself, 
if  any  is  done." 

Billy  now  tuned  back  for  the  burglars. 

"I'm  only  a  few  blocks  away,"  he  an- 
nounced. "I'll  be  there  in  a  few  minutes. 
Keep  a  lookout  at  the  front  window. 
You'll  know  it's  me  when  I  get  out  and 
walk  around  the  car." 

"All  right,"  responded  both  burglars 
eagerly. 

"It  looks  as  if  we've  got  them  trapped," 
remarked  Billy,  throwing  the  switch  over. 
"I  wish  I'd  asked  Charley  to  go  into  the 
house  and  tell  us  about  it  after  it's  all 
over." 

"Maybe  he  will  anyway,"  Alice  sug- 
gested. "It  would  be  the  natural  thing 
for  anybody  to  do.  Throw  the  switch 
back,  Billy,  and  let's  listen  in.  We  may 
hear  something. 

"All  right,"  said  Billy. 

(Turn  to  next  page) 


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(  Continued  from  preceding  page) 

For  several  minutes  they  listened  to  a 
low  hum  of  conversation  between  the 
burglars;  then  Bimbo  said: 

"I  hear  a  machine  outside,  Sam.  I 
guess  he's  come." 

They  moved  away  from  the  vicinity 
of  the  microphone,  apparently,  for  the 
listening  campers  heard  no  more  for  the 
time  being.  For  fifteen  minutes  longer 
they  listened  with  hopes  and  doubts. 
Then  their  hopes  were  realized: 

"Hello,    Honeymoon    Camp." 

It  was  the  voice  of  Charley  Patterson. 

"Hello,  Charley,"  Billy  returned. 

"We  caught  'em  hands  down,"  came 
the  announcement,  which  everybody  in 
camp  drank  in  eagerly.  "We  brought 
them  back  into  the  house,  and  I  want  to 
introduce  them  to  you  by  radio.  Are  you 
all  there?" 

"Yes,  we're  all  here." 

"Well,  burglars,  these  are  six  very 
arrogant  and  opinoniated  honeymoon 
campers.  Ever  since  they  were  married 
they've  turned  their  noses  up  at  all  their 
friends  in  town.  They  were  the  life  of 
all  our  social  events,  and  our  'crowd'  just 
went  to  pieces  since  they  went  and  got 
married.  In  order  to  accommodate  us, 
you  burglars,  Sam  and  Bimbo,  broke 
into  the  home  of  the  parents  of  one  of 
the  brides  and  helped  us  get  our  revenge. 
We  planned  this  revenge  several  weeks 
ago,  dropping  hints  to  the  honeymooners 
that  they  ought  to  go  camping  and  take 
a  complete  radio  outfit  with  them. 

"We  planned  to  repeat  this  burglary 
stunt  night  after  night  until  success 
crowned  our  efforts.  We  had  several 
schemes  whereby  we  hoped  to  catch  them 
if  they  proved  difficult  to  entrap.  We 
were  going  to  use  every  wavelength  al- 
loted  to  amateurs.  But  they  fell  easy 
prey  the  very  first  night  early  in  the 
evening,  and,  my!  what  ingenuity  they 
exercised    to    remain    in    our    clutches. 


"Honeymoon  campers,  allow  me  to 
present  to  you  the  burglars  whom  you  so 
kindly  and  industriously  aided  us  to 
capture.  First,  here  is  Bimbo,  an 
elongation  of  Bim,  which  is  made  up  of 
three  letters,  the  initials  of  one  of  the 
friends  you  deserted,  Burt  Iverson  Morris. 
Second,  here  is  Sam,  a  name  made  up  of 
the  initials  of  another  of  your  deserted 
society  friends,  Stephen  Appomatox  May- 
fair.  Like  all  the  rest  of  us,  they  are 
lonesome  for  you  and  demand  that  you 
make  your  honeymoon  complete  once 
for  all,  so  that  when  you  return,  there  will 
be  no  more  nonsense,  and  you  will  resume 
the  places  society  long  ago  allotted  to  you 
and  now  demands  that  you  fill. 

"Early  in  the  development  of  our 
society  plot,  we  got  Ray  Harrison's  con- 
sent to  use  his  radio  station  at  home;  we 
also  broadcast  our  plan  to  the  amateur 
world  on  two  evenings  when  we  knew 
none  of  you  were  listening  in.  Most  of 
them,  no  doubt,  for  hundreds  of  miles 
around,  are  now  eagerly  listening  for  the 
denouncement  of  this  drama  of  the  ether 
and  we  will  now  turn  the  ether  over  to 
them  in  order  that  they  may  give  this 
affair  its  proper  artistic  finish. 

"Now,  Hams,  ready,  all;  give  them  the 
raz — razberry  with  a  Z,  a  string  of  Z's. 
Split  the  ether  like " 

The  last  word  was  never  heard.  The 
ether  sure  was  split  as  it  never  was  split 
before  and  may  never  be  split  again — 
howls,  yowls,  spark  spits,  cat  calls, 
screams,  whistling,  wheezing,  and  a 
regular  firmament  of  "manufactured 
static."  "Blue  ether"  was  no  longer  a 
mere  figure  of  speech. 

*      *      * 

It  is  needless  to  say  that  when  the 
honeymooners  returned  home  they  bowed 
gracefully,  though  blushingly,  to  the 
social  inevitable. 


THE  END. 


How  Radios  "Leading  Lady 
to  Theatrical  Fame 


Rose 


other  voice:  otherwise  the  listener  be- 
comes confused.  Characters  are  identi- 
fied solely  by  sound.  For  this  reason 
the  small  cast  play  is  more  effective  via 
radio  than  a  play  requiring  ten  or  twelve 
people. 

Radio  "Made"  Her 

BEFORE     attending     the     Teachers' 
College,  Miss  Greene  was  a  student 


(  Continued  from  page  27 ) 

the  inspiration  to  be  derived  from  a  re- 
sponsive group  of  people ;  he  has  only 
someone's  word  for  it  that  his  voice  is 
going  outside  the  room. 

Miss  Greene  knows  that  her  voice  is 
going  over  hundreds  of  miles  into  thou- 
sands of  homes  to  the  ears  of  all  condi- 
tions of  people.  She  has  trained  herself 
to  live  the  part  she  is  playing  without 


at  the  New' York  University  and,  in  her     thought  of  the  effect  her  work  may  be 


freshman  year,  she  was  associated  with 
the  Washington  Square  Players.  It  was 
then  she  gained  the  only  experience  in 
dramatic  work  she  had  before  joining 
the  WGY  players. 

Miss  Greene's  success  as  a  radio  player 
is  partly  due  to  the  fact  that  she  has  not 
had  much  experience  on  the  stage.  The 
professional,  when  acting  before  the 
microphone,  is  handicapped  by  the 
absence  of  a  visual  audience:  he  misses 


having  on  the  listeners  at  the  time. 

The  letters  which  follow  in  a  day  or 
two  gratify  the  love  of  the  artist  for 
applause.  When  a  Canadian  guide 
writes  that  for  a  time  he  wanted  to  kill 
the  villain  who  was  torturing  her,  Miss 
Greene  feels  that  she  gave  a  convincing 
performance.  When  a  forest  ranger 
brushed  tears  from  his  eyes  during  an 
emotional  piece  of  work  by  Miss  Greene, 
no  further  applause  is  necessary. 


What  will  be  next?      A  millinery  show  over  the  radio  is  the  latest  radio  twist 
adopted  by  an  Eastern  broadcasting  station.   Read  about  it  in  the  May  RADIO  AGE. 

*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  April,  1925 


Thz  Magazine  of  the  Hour 


65 


Growing  Wiser  with  the 
"Hoot  Owls" 

(Continued  from  page  25) 
They  "Ride  the  Goat" 
k  PPROPRIATE    emblems,    with 


the 


-^*-  insignia  of  the  Pet  Hoot  Owl  to  be 
seen  on  Page  25  of  this  issue,  are  sent  to 
each  newly  initiated  member  of  the  Hoot 
Owls,  as  ample  proof  he  has  travelled 
on  "the  goat"  at  the  hands  of  Dick 
Haller,  holder  of  the  Grand  Goat,  which, 
by  the  way,  is  the  mythical  animal  used 
to   "torment"   the  candidates. 


Miss  Louise  Jacobsen 


KGW  does  not  confine  its  activities  to 
the  Hoot  Owls.  Weather  reports,  bed- 
time stories,  classical  and  popular  pro- 
grams, and  syncopating  dance  music 
from  the  Hotel  Multnomah  "Strollers" 
all  help  to  vary  the  program.  Church 
services,  broadcasts  of  municipal  concerts 

'P1CHAT5D- 
1HE    OWL 

HE*i?Tf:D 


from  the  public  auditorium  of  Portland, 
lectures  from  the  University  of  Oregon 
and  market  reports  are  other  features 
which  are  carefully  prepared  each  week. 
Louise  Jacobsen,  a  comely  young 
Oregonian,  is  KGW's  most  popular  con- 
cert pianist.  She  is  an  acknowledged 
artist  on  the  concert  platform,  but  she  is 
even  more  exceptional  when  it  comes  to 
radio  broadcasting. 


'The  Traffic  Cop  of  the  Air 

"KYW—  stop!  Enter  not  into  the  realm  of  Music  and 
Fancies!  Know  ye  not  that  WOX  has  the  stage? 
Thou  shalt  not  enter  to  interfere!" 

.  .  .  *Tis  the  far-famed  Traffic  Cop  speaking — and 
his  word  is  law.  The  Ferbend  Wave  Trap  is  respec- 
ted and  the  interfering  station  pleasantly  bows  out. 

You,  too,  can  make  your  set  selective — separate  the  interfering 
station,  by  simply  putting  the  Traffic  Cop  on  guard. 

The  Ferbend  Wave  Trap  will  tune  out  interfering  local  stations* 
no  matter  how  troublesome.  Never  reduces,  but  nearly  always 
increases  volume.  By  the  addition  of  a  new,  improved  circuit,  the 
Ferbend  Wave  Trap  now  gives  you  several  new  hook-ups,  and  at 
the  same  time  can  be  used  to  convert  a  single  circuit  regenerative 
set  into  a  three-circuit  regenerative  receiver  thereby  practically 
eliminating  all  radiation  from  the  set. 

Designed  and  manufactured  complete  by  us  after  years  of  care- 
ful experimenting.  It  is  not  to  be  confused  with  imitations,  hastily 
assembled  from  ordinary  parts.  The  price  is  $8.50.  Shipment  is 
made  Parcel  Post  C.O.D.,  plus  a  few  cents  postage.  If  you  prefer, 
you  can  send  cash  in  full  with  order,  and  we  will  ship  postage  pre- 
paid. Clip  and  mail  the  COUPON  today! 

FERBEND  ELECTRIC  COMPANY 

16  E.  South  Water  Street  Chicago,  Illinois 

FERBEND 


4 


East  Pittsburgh,  Pa. 
December  20, 1924. 
Ferbend  Electric  Co. 
Gentlemen:  I  live  less 
than  two  miles  from 
the  antenna  of  kdka, 
the  powerful  Westing- 
house  Station  (1000 
watts) ,  at  present, and 
while  they  were  on  I 
could  get  absolutely  no 
other  stations — even 
otherlocalsafewmik-s 
away.  You  can  imag- 
ine my  amazement  last 
night  when  I  tried  my 
Ferbend  out  to  receive 
woe,  Davenport.WBZ, 
Springfield,  [only  11 

METERS  FROM  KDKAj 
KSD,  St.  LouiS,  WTAM, 
Cleveland,  weaf,N.Y. 
City,  wjy.  N.  Y.  City 
wbav,  Columbus,  and 
eight  or  nine  others 
without  so  much  as 
a  whisper  from  KDKA 
which  was  broadcast- 
ing  full  power. 
Very  truly  yours, 
Chas.  Marberry 


2?£?>fi£ 


FERBEND  ELECTRIC  CO.,  16  E.  So.  Water  St.,  Chicago,  111. 
Gentlemen:  Please  send  me: 

i  enclosing  (check,  M.  O., 


□  WAVE  TRAP.  Send  poetpaid.  I  e 
etc.)  forS8.50. 


□  FREE  BOOKLET  c 

Name 

Address 

City 


to 


i  Interference. 


RADIO  AGE  SUBSCRIPTION  BLANK 


$2.50  A  YEAR 


Radio  Age,  Inc., 

500  North  Dearborn  Street, 
Chicago 

Gentlemen:  Please  enter  my  subscription  for  RADIO  AGE,  the  Magazine  of  the  Hour,  for  one 
year,  beginning  with  your  next  issue,  for  which  I  enclose  $2.50. 


Street  Address  . 


City  . 


Send  cash,  money  order  or  draft. 


*     Tested  and  Approved   by  RADIO   AGE      ¥ 


66 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Do  you  want  to  make  more  money  in 
your  spare  time?      See  page   57. 


"Nighthawks"  Win  Contest 
for  February 

( Continued  from  page  26) 

Each  month  seems  to  pull  a  heavier 
vote  than  that  preceeding,  and  while  Karl 
Bonawitz  still  leads,  it  will  be  noticed 
that  Bill  Hay  has  strengthened  his  own 
position  by  advancing  from  third  to 
second  place.  Coon-Sanders'  Night- 
hawks  spring  the  surprise  this  month  by 
taking  the  position  vacated  by  Bill  Hay, 
although  not  previously  indicated  in  the 
monthly  tabulations  shown  in  RADIO 
AGE. 

Some  Advances 

Jack  Nelson,  Ford  and  Glenn  and 
'Sen"  Kaney  all  made  slight  advances 
during  the  month.  New  names  to  ap- 
pear in  the  list  this  issue  are  Banks 
Kennedy,   S.    Hasting     and   Bob   Boniel. 

Last  month,  through  an  error,  the 
final  day  of  the  contest  'i'as  indicated 
as  midnight,  June  5.  The  apology  is  all 
ours  in  correcting  this  to  Jure   15. 

The  end  is  rapidly  approaching.  What 
are  you  doing  to  see  that  your  favorite 
carries  away  the  grand  prize  for  the  1924- 
25    season? 


To  the  Man  with  an  Idea 

I  offer  a  comprehensive,  expe- 
rienced efficient  service  for  his 
prompt,  legal  protection  and  the 
development  of  his  proposition. 

^  Send  sketch  of  model  and  descrip- 
tion, for  advice  as  to  cost,  search 
through  prior  United  States  patents,  1 
etc.         Preliminary    advice    gladly 
furnished  without  charge. 

My  experience  and  familiarity  | 
with  various  arts  frequently  enable  [ 
me  to  accurately  advise  clients  as  ' 
to  probable  patentability  before  I 
they  go  to  any  expense. 

Booklet  of  valuable  information  and 
form  for  properly  disclosing  your 
idea  free  on  request.     Write  today. 

|  RICHARD  B.  OWEN,  Patent  Lawyer 

81  Owen  Bldg.,  Washington,  D.  C. 
2278-M  Woolw-orth  Bldg.,  N.  Y.  City 


GET     YOUR     1925     ANNUAL 
WHILE  THEY  LAST! 


THE  RADIO  AGE  BUYERS'  SERVICE 


What  do  you  want 
Enter  the  number  of  the 

1  "A"  Batteries 

2  Aerial  protector* 

3  Aerial  insulators 

4  Aerials 

5  Aerials,  loop 

6  Ampli6ers 

7  Amplifying  units 

8  Ammeters 

9  "B"  batteries 

10  Batteries    (state  voltage) 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery   substitutes 

17  Bezels 

18  Binding  posts 

19  Binding  posts, 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatstone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practiaers 
13  Coils 

34  Coils,  choke 

35  Coils,  coupling 

36  Coils,  filter 

37  Coils,  grid 
,  honeycomb 

ctance 


alated 


to  purchase  in  th 

e  radio  line? 

article 

/on  would  like  to  know 

57 

Couplers, 

loose 

58 

Couplers, 

molded 

59 

Couplers, 

vario 

60 

Crystal  alloy 

61 

Crystal  h 

aiders 

62 

Crystals, 

roush 

63 

64  Crystal*, 

65  Crystals, 

unmounted 

66  Crystals, 

mounted 

67 

Desks,  radio 

68 

Detector 

units 

69 

Detectors 

,  crystal 

70 

Detectors 

,  fixed  crystal 

71 

Dial,  adjusters 

72 

Dials,  cot 

73 

Dials,  ha, 

d  rubber 

74 

Dials,  rhe 

ostat 

75 

Dials,  me 

tal 

76 

Dials,  ver 

77 

Dials  with  knobs 

78 

Dies 

79 

Drills,  ele 

ctric 

80  Dry  cells 

81 

Earth  gro 

und. 

82 

Electrolyl 

83 

Enamels, 

battery 

84 

Enamels, 

metal 

85 

End  stope 

86  Eyelets 

87 

E*perime 

ntal  work 

88 

Fibre  she 

St,  vulcanized 

89 

Filter  reactors 

90 

Fixtures 

Let  the  staff  of  RADIO   AGE  save  you 
more  about  in  the  spaces  provided  in  the 


time   and   money   by   sending   in   the   coupon   below, 
coupon. 


38  Coils 

39  Coils 

40  Coils 

41  Coils 

42  Coils 

43  Cone 

44  Cond 

45  Cond 
lii 


Re 


art* 


stabilizer 
ing 

■  plates 
-s,  antenn 


46  Con 

47  Con 

48  Con 

49  Con 
srid 

50  Con 

51  Con 

52  Con 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  sets 


sers,  fixed  (paper, 
phonel 
sers,  variable  grid 


92  Fus 

93  Ger 
cy 


es,  tube 

lerators,  high  frequen 


94  Grid  choppers,  rotarj 

95  Grid  leak  holders 

96  Grid,  transmitting  le 

97  Grid  leaks,  tube 

98  Grid  leaks,  variable 
electric 


99   G 

100  G: 

101  Gi 

102  H; 

103  H 

104  H 


nd  cla 


:ips 


ound  rods 
ndles,  switch 
ad  bands 
ad  phones 

105  Head  sets 

106  Honeycomb  coil  adapte: 

107  Hook  ups 

108  Horns,  composition 

109  Horns,  fibre 

110  Horns,  mache 

111  Horns,  metal 

112  Horns,  wooden 

113  Hydrometers 


114  In 

115  In 

116  In 

117  In 

118  In 

119  In 

120  In 

121  In 

122  In 

123  In 


a  tors,  polarity 
:tances,  C.  W. 
ation,  molded 


al 


ulators,   fibre 
ulators,   high  voltage 
ulators,  cloth 
ulators,  glass 

124  Insulators,  hard  rubber 

125  lunula. ors,   porcelain 

126  Irons,  soldering 

127  Jacks 

128  Filament  control 

129  Jars,  battery 

130  Keys,  transmitting 

131  Knobs 

132  Knock-down  panel  units 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arresters 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  units 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instruments 

142  M ego h meters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeters 

148  Minerals 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,       condenser 
leak 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,   honeycomb 
coil 

156  Mountings,      inductance 
switch 

157  Name  plate3 

158  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeters 

161  Oscillators 

162  Panel  cutting  and  drilling 

163  Panels,      drilled     and     un- 
*      "ed 


164  Panels,  fib 

165  Pant 

166  Part 

167  Past 


Patent  attorneys 
Phone  connectors,  multi- 
ple 

Phonograph  adapters 
Plates,  condenser 
Plugs,  coil 
Plugs,  telephone 
Pointers,  dial  and  knob 
Poles,  aerial 
Potentiometers 
Punching  machines 
Reinartz  set  parts 
Regenerative  set  parts 
Receiver  caps 

181  Rectifiers,   battery 

182  Resistance  leaks 

183  Resistance  units 

184  Rheostat  bases 

185  Rheostat  strips 

186  Rheostats,  automatic 

187  Rheostats,  battery 

188  Rheostats,  dial 

189  Rheostats,  filament 

190  Rheostats,     potentiometer 

191  Rheostats,  power 

192  Rheostats,  vernier 

193  Rods,  ground 

194  Rotors 

195  Scrapers,  wire 

196  Screwdrivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving — cabinet 

200  Sets,  receiving — crystal 

201  Sets,     receiving — knock- 
down 

202  Sets,        receiving    —    Neu- 
trodyne 

203  Sets,  receiving—portable 

204  Sets,    receiving — radio    fre- 


1s,  hard  rubber 


nittin 


Sets,  recei- 

Sets,     rece 

generative 

Sets,  trans 

Slate 

Shellac 

Sliders 

Socket  adapters 

Sockets. 

Solder 

Soldering  irons, 

Soldering  paste 

Solder  flux 


— regenera- 

-Reinartz 

-sectional 
-short  wave 
— super-re- 


221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tub*"* 

224  Spark  coils 

225  Spark  gaps 

226  Stampings 

227  Stators 

228  Stop  points 

229  Switch  arms 

230  Switch  levers 

231  Switch  points 

232  Switch  stops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,   filament 

236  Switches,  ground 

237  Switches,  inductance 

238  Switches,  panel 

239  Switches,  single  and  dou- 
ble throw 

240  Tone  wheels 

241  Towers,  aerial 

242  Transformers,     audio     fre- 
quency 

243  Transformers,  filament 

244  Transformers,   modulation 

245  Transformers,    power 

246  Transformers,    push-pull 

247  Transformers,      radio     fre 
quency 

248  Transformers,  variable 

249  Transmitters 

250  Tubes,  vaccuum — peanut 

251  Tubes,    vacuum — two    ele- 
ment 

252  Tubes, 


253  Tu 

254  Va 

255  Va 

256  Va 

257  Va 

258  Va 

259  Va 

260  Va 

261  Voltmeters 

262  Wash. 

263  Wave 

264  Wave  traps 

265  Wir 

266  Wir 
ed 

267  Wir 

268  Wir 

269  Wir 

270  Wir 

271  Wir 

272  Wir 


m — three  ele- 


libber 


couple:     , 
couplers,   molded 
couplers,  wooden 
meters,   hard  rubber 
meters,  molded 
meters,  wooden 
h,  insulating 


ten 


!,  copper 
s,  insulated 
:,  Litz 
:,  magnet 

:,  tungsten; 


RADIO   AGE    BUYERS'  SERVICE,  500   N.  Dearborn   St.,   Chicago,   III. 

Please    see    that   I    am    supplied  with    buying   specifications    and    prices   on    the    articles   numbered    herewith: 

i         i         i         I         I         i         i         i         i         i         i         i         i 


I  am  a —   Q   Dealer  J    Jobber  1    Mfgrs.'   Rep.  □    Manufacturer 

Firm      [If   identified  with  Radio   industry]    - _ _ _ 

My    Occupation  _ —  My    Name 


,    State   


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


67 


A  3 -Tube  Portable  Set  for 
Your  Vacation 

(Continued  from  page  10) 

make  the  set  so  that  it  can  be  used  in  a 
cabinet  at  home  when  it  is  not  desired 
to  keep  it  in  a  case  such  as  a  portable  set 
requires. 

The  two  binding  posts  (A  and  G)  will 
be  mounted  on  the  panel  at  the  upper 
right  corner.  These  binding  posts  are 
for  the  antenna  and  ground  respectively, 
and  should  be  big  and  sturdy  so  as  to 
take  the  large  wire  to  be  used.  The  five 
binding  posts  for  battery  supply  will  be 
mounted  on  the  panel  also;  two  at  the 
lower  right  corner  and  three  at  the 
lower  left  corner.  Those  at  the  right 
are  for  the  "A"  or  filament  battery. 
They  will  be  marked  (A —  and  A  +  ). 
The  three  at  the  left  are  for  the  "B" 
or  plate  battery  and  will  be  marked 
(B— ,  BB  and  BD). 

A  Neat  Mounting  Job 

TO  MAKE  a  neat  looking  job  of 
mounting  the  instruments,  it  would 
be  well  to  use  number  six,  flat  head, 
blued  machine  screws  and  counter  sink 
the    panel    so    that    they    will    be    flush. 


THE    PARTS    NECESSARY 
TO  BUILD  THE  SET 

2  Small,  well-shielded  audio  transformers 
(Al,  A2.) 

1  Variable  condenser,  23  plate — tuning 
unit. 

1  Eighteen-tum  spider  web  coil — tuning 
unit. 

1  Sixty-eight-turn  spider  web  coil — tuning 
unit. 

1  Tube  control  rheostat,  sixteen  ohms. 
(Rl.) 

2  Tube  control  Amperites.     (R2,  R3.) 

1  Grid  leak  and  condenser  for  WD12  type 
tubes.      (GL.) 

1  Single  circuit  phone  jack.  (P) 
1  Fixed  condenser  .00025  mf.      (B) 
1  Fixed  condenser  .005  mf.      (C) 

3  201  type  tube  sockets.     (D,  Tl,  T2) 

3  WD-12  tubes. 

1  Phone  cord,  six  or  eight  inches  long. 
1  Phone  plug. 
1  Battery  switch.      (S) 

7  Binding  posts.  (A,  G.  A — ,  A+,  B — , 
BD,  BB) 

1  Loud  speaker  of  the  reflected  tone  type. 

4  Small  22  3  2  volt  "B"  batteries. 

3  Standard    dry    cells    for     "A"    battery. 
(To  be  connected  "multiple.") 
50  Feet  of  antenna  wire. 

2  Insulators  for  antenna. 

15  Feet  of  insulated  wire  for  ground  and 
antenna  connections. 

1  Metal  rod  or  pipe  for  ground. 


The  terminal  screws  on  the  sockets 
may  be  removed  and  put  in  so  that  the 
terminal  side  or  side  with  the  nut  is  on 
the  lower  side  of  the  socket. 

In  wiring  the  set,  be  sure  to  solder  all 
of  the  connections  well,  as  the  vibration 
and  jolts  a  portable  set  is  subjected  to 
will  soon  loosen  up  a  poorly  soldered 
connection  and  put  the  set  out  of  opera- 
tion. The  leads  should  all  be  as  short 
as  possible  and  no  two  leads  run  parallel 
to  one  another.  Number  fourteen,  bare 
tinned  wire  or  the  usual  tinned  bus  wire 
is  recommended. 

The  loud  speaker  neednot  be  included 
in  the  panel  layout  if  it  is  desired  to  use 
one  you  may  already  have,  or  perhaps 
you  would  rather  use  head  phones.  The 
single  circuit  jack  (P)  is  put  into  the 
circuit  so  as  to  enable  the  operator  to 
use    either    at    will.      It    is    much    more 


Iransfc 


ransiormer 


Result 


Correct  loud  speaker  performance  depends  almost  entirely 
upon  transformer  design.  Jefferson  Transformers  provide 
full,  rich,  smooth  amplification.  They  furnish  the  loud 
speaker  with  the  proper  energy  and  assure  the  greatest 
possible  volume  consistent  with  purity  of  tone. 

Even  amplification  over  the  entire  musical  range;  perfect 
reproduction  of  the  voice  and  instrument — these  are  some  of 
the  reasons  why  radio  authorities  and  music  lovers  the  world 
over  recognize  Jefferson  superiority. 

Designed  by  a  concern  which  has  specialized  for  more  than 
20  years  in  the  manufacture  of  high  grade  transformers  of 
every  description.  Jefferson  Transformers  meet  the  most 
exacting  demands  of  every  circuit.    Give  your  circuit  a  treat 

— install  Jeffersons. 


Ask  for  latest  Jefferson  Circuit  diagrams. 


JEFFERSON  ELECTRIC  MFG.  CO. 

50  7  S.  Green  St.,  Chicago,  111. 


* 


Manufacturers  of 

Bell  Ringing  Transformers 

Sign  Lighting  Transformers 

Toy  Transformers 

Heavy  Duty  Signal  Transformers 

Auto  Transformers 

High  Voltage  Transformers 

Welding  Transformers 

Automobile  Ignition  Coils 

Jump  Spark  and  Make  and  Break 
Coils 

Testing  Instruments 

Gas  Furnace  and  Oil  Burner  Trans- 
formers 

and  Ignition  Equipment 


5000 

RADIO  DEALERS 

buy  from 

HUD50NR0SS 

123  W.  Madison  St.  Chicago 

Send  for  dealers  discount. 


DeForest 
License 


HONEYCOMB  C0I1S 

The  Universal  all-wavf 
inductance.    Back   and 
front  panel  mountings. 
Send     25c    for     Super 
Het.,  R.  F.  and  Honey- 
comb Coil  Circuits  and 
Complete  Catalog. 
Cbas.  A.  Brans  too,  Ic*. 
Dept.  13, 
815  Main  St.,  Buffalo,  N.  Y. 


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68 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Radio  Fans 


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RADIO  AGE  ON  THE  AIR! 
Hear  one  of  RADIO  AGE's  unusual  broadcast  programs  from 
KYW,  beginning  at  11 :45  p.  m.,  Saturday,  April  4,  from  the  "Little 
Red  Studio"  in  the  Congress  Hotel.  Jazz  galore.  Also,  a  program 
of  popular  and  semi-classical  numbers  from  WEBH,  11  to  12  p.  m., 
Tuesday,  March  24.     Tune  in,  fans ! 


handy  than  binding  posts  on  the  panel 
and  presents  a  more  neat  appearance. 

When  the  set  has  been  completely 
wired  and  tested  out,  you  will  be  ready 
to  mount  it  into  the  case.  This  will  be 
done  by  use  of  six  brackets  shown  in 
figure  three  as  detail  two.  The  panel 
should  be  placed  about  one  half  an  inch 
below  the  edge  of  the  case  so  as  to  allow 
the  cover  to  close  down  over  the  dials 
and  binding  posts.  Next,  cut  two 
pieces  of  wood,  about  three-sixteenths  of 
an  inch  in  thickness,  to  fit  under  each 
side  of  the  panel  and  to  entirely  close 
the  space  between  the  panel  and  the 
back  of  the  case.  The  space  thus  formed 
will  be  used  for  the  "A"  and  "B"  bat- 
teries. These  pieces  should  be  securely 
fastened  in  place,  as  it  is  protection 
against  the  batteries  coming  loose  and 
damaging  the  wiring  of  the  set. 

Two  straps  should  be  secured  and  cut, 
so  as  to  have  one  piece  complete  with  a 
buckle  about  five  inches  in  length,  one 
piece  complete  with  buckle  about  six 
inches  in  length,  one  piece  with  buckle 
holes,  ten  inches  long  and  one  piece 
five  inches  long.  These  straps  are  for 
holding  the  batteries  in  place  in  the  case 
and  will  be  made  fast  to  the  case,  as 
shown  in  figure  two. 

Carrying  the  Antenna 

'THVO  clips  may  be  made  fast  to  the 
■*■  cover  of  the  case  to  carry  the  antenna 
wire  when  not  in  use.  This  wire  will  then 
be  rolled  into  a  coil  when  it  is  taken 
down  and  placed  in  the  set,  keeping  it 
ready  for  use  without  the  usual  patience- 
trying  job  of  untangling  it  from  the 
bottom  of  everything  where  things  like 
that  are  usually  found. 

To  put  the  set  into  operation,  first 
select  a  spot  about  fifty  feet  from  a  tree 
in  a  clearing,  fasten  one  end  of  the 
antenna  to  this  tree  as  high  up  as  con- 
venient, bring  the  other  end  to  a  place 
near  the  set  and  make  it  fast  to  a  point 
about  six  feet  or  more  above  the  ground. 
The  tent  pole  will  do  very  nicely.  Con- 
nect this  end  of  the  antenna  to  the  bind- 
ing post  (A).  The  metal  rod  will  then 
be  hammered  into  the  ground  in  a  damp 
spot  or  in  a  stream  or  other  water  and 
connected  to  the  binding  post  (G). 
Insert  the  three  tubes  into  their  respec- 
tive sockets  and  operate  the  switch  to 
the  ON  position.  Adjust  the  detector 
rheostat  so  that  the  tube  will  glow  and 
proceed  to  tune  with  the  dial   (T). 

All  of  the  tuning  will  be  accomplished 
by  the  dial  (T)  and  the  detector  rheostat 
and  you  will  be  surprised  at  the  clear 
tone  and  sharp  tuning  you  will  be  able 
to  get. 

This  set  has  shown  some  good  DX 
reception  and  unless  one  wants  to  go  into 
the  multi-tube  super-heterodyne  re- 
ceivers, it  is  a  good,  all  around  circuit 
for  the  use  it  is  intended. 


FREE  SUBSCRIPTIONS! 
Do  you  want  a  free  subscrip- 
tion to  RADIO  AGE — or  your 
present  subscription  renewed  free 
of  charge?  Read  our  special  offer 
on  page  52. 


RADIO  AGE  for  April,  1925 

The  First  Real  Radio 
Inauguration 


The  Magazine  of  the  Hour 


69 


WASHINGTON,  D.  C— No  imposing 
parade,  no  immense  bodies  of  troops, 
no  triumphant  marching  clubs  wearing 
ribbon-bedecked  hats,  no  distinguished 
citizens  from  elsewhere  in  moth  ball 
odored  frock  coat  sand  ancient  and  modern 
silk  hats,  no  civilians  riding  resurrected 
but  frequently  capricious  and  invariably 
rented  livery-stable  horses,  no  incessant 
booming  of  drum  corps,  no  miles  of  shaky 
temporary   reviewing   stands. 

No  lodging-house  windows  selling  at 
$25.00  a  look,  no  ham  sandwiches,  no 
hot  dogs,  no  bottles  of  soda  pop,  no 
balloons  breaking  away  from  their 
moorings,  no  crowds  of  persons  fighting 
for  hours  to  keep  their  places,  no  crying 
and  terribly  tormented  babies  in  arms, 
no  courts  of  honor,  no  fireworks,  no 
ambulances,  no  overworked  policemen. 
Such  was  the  order  of  the  day  in  the 
inauguration  of  President  Coolidge  on 
Wednesday,  March  4. 

President  Wilson  really  sounded  the 
death  knell  of  the  old  country-fair  style 
inaugurals.  Up  to  that  time  the  Capital 
was  demoralized  for  a  week  before  and 
a  week  after  the  celebration.  So  many 
visitors  descended  upon  the  city  that 
Government  employes  from  cabinet 
officers  to  clerks  were  able  to  do  little  or 
no  work. 

President  Harding  fell  into  step  with 
the  reform  and  President  Coolidge  is 
going  both  of  them  one  better.  His 
first  reason  is  that  of  economy;  his 
second,   preference  for  simplicity. 

In  the  old  days  the  inaugural  address 
■was  the  piece  de  resistance,  although  it 
took  days,  weeks,  and  even  months 
through  slow  methods  of  transportation 
and  less  highly  developed  newspapers 
to  get  it  to  the  people.  It  was  thought 
revolutionary  when  President  Harding, 
at  the  last  inauguration,  by  means  of 
loud  speakers  was  heard  by  a  crowd  of 
upwards  of  100,000  persons  in  and 
around  the  Capitol  grounds.  It  was 
suggested  that  by  telephone  wires  the 
Harding  address  could  be  carried  to  the 


How  to  Build 

and  Operate  the 

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Consists  of  1  Low  Loss  Tun- 
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Fixed  Condensers. 
To  protect  the  public,  Mr. 
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Heard  Europe  on  a  Home  Built 
Ultradyne  Model  L-2. 
Arthur  Bender,  116  East  2nd 
Street,  Covington,  Ky.,  had  no 
trouble  picking  up  European 
stations  last  week  on  his  eight 
tube  Ultradyne  which  he  con- 
structed himself, 
Cincinnati  Enquirer,  Nov.  30, 1924 


lousands  have  Suit  it! 


Like  Mr.  Bender,  thousands  have  successfully  built 
the  Model  L-2  Ultradyne  and  claim  it  the  most  won- 
derful receiver  they  have  ever  known  for  great  distance 
on  the  Loud  Speaker. 

In  no  other  receiver  is  found  the  "Modulation  System" 
of  radio  reception — an  outstanding  radio  engineering 
development  by  R.  E.  Lacault,  E.  E.,  A.  M.  I.  R.  E., 
Chief  Engineer  of  this  Company  and  formerly  Radio 
Research  Engineer  with  the  French  Signal  Corps, 
Research  Laboratories. 

With  the  application  of  regeneration  to  the  "Modula- 
tion System"  the  Ultradyne  is  capable  of  detecting  the 
faintest  broadcast  signal,  regenerating  and  making  it 
audible  on  the  loud  speaker. 

In  addition,  the  Ultradyne  is  the  most  selective  receiver 
known.  Regardless  of  close  similarity  in  wave  length, 
it  selects  any  station  within  range — brings  in  broad- 
casting clearly,  distinctly,  faithfully. 
The  Model  L-2  Ultradyne  will  do  everything  better 
than  any  super-radio  operating  under  the  same  condi- 
tions. 
Write  for  descriptive  circular. 


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NEW  YORK 


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22  feet  Bold  buswire,  lithographed  print,  complete,  sim 
pie  instructions — prepaid  anywhere,  S5.00.  Nothing  else 
to  buy.  Details,  10c.  48  page  parts  catalog,  10c. 
Stamps  accepted  same  as  cash. 

Kladag  Radio  Laboratories,  Kent,  O. 


HUDSON-ROSS 

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70 


RADIO  AGE  for  April,  1925 


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This  most  recent  Duplex  achieve- 
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Instructive  literature  sent  on  request. 

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Brooklyn,  New  York 


Marion  High  School,  so  that  Mr.  Hard- 
ing's sister,  who  was  the  principal  of 
the  school,  might  be  able  to  hear  it,  but 
in  the  excitement  of  the  occasion,  this 
plan  was  not  carried  out.  There  was  no 
broadcasting  being  done  at  that  time  to 
speak  of.  What  then  seemed  like  a  wild 
dream  is  now  a  reality. 

By  the  most  gigantic  of  all  hook-ups 
in  the  history  of  radio,  the  inaugural 
address  was  carried  by  a  chain  of  radio 
stations  to  17,500,000  people.  This  is 
as  many  persons  as  there  were  in  the 
entire  United  States  in  1840,  three  years 
before  the  first  telegraph  line  in  the 
country  was  built  connecting  Washing- 
ton and  Baltimore;  seventeen  years 
before  the  laying  of  the  Atlantic  cable, 
and  twenty-six  years  before  the  telephone 
was  invented. 

Feeling  the  importance  of  getting  the 
text  of  the  inaugural  address  to  the 
citizens  of  the  country,  President  Cool- 
idge  welcomed  the  opportunity  which 
radio  affords  the  present-day  American 
man  who  may  sit  in  his  office  or  in  his 
home  and  hear  the  speech  as  it  is  made. 
Another  problem  of  the  newspapers  in 
the  old  days  was  to  secure  photographs 
of  the  ceremony.  On  previous  occasions 
enter-publications  have  gone  so  far  as 
to  charter  special  trains,  and  later  air- 
planes f<— •  th  s  purpose.  In  this  in- 
auguration riJio  photographs  were 
flashed  across  the  country  ?nd  over  the 
ocean  as  well. 


The  Magazine  of  the  Hour 

BUILD  YOUR  OWN 

B-ELIMINATOR 


I  sham  Jones  On  Radio 

( Continued  from  page  32) 

does  not  over-balance  the  work  of  the 
entire  unit." 

Jones  contends  that  one  of  the  great 
problems  to  be  worked  out  for  the  radio 
is  the  matter  of  broadcasting  programs 
that  are  attractive,  well  balanced  and 
educational.  He  does  not  favor  the 
indiscriminate  methods  sometimes  em- 
ployed. Isham  Jones  is  opposed  to  a 
censor  for  radio,  his  position  being  that 
eventually  some  sort  of  arrangement  will 
be  worked  out  to  guarantee  programs  of 
the  highest  order  as  well  as  solve  many 
of  the  questions  that  are  irksome  at  the 
present  time. 

"That  the  radio  has  possibilities  I 
think  no  one  will  deny,"  said  Mr.  Jones. 
"The  advertising  value  alone  is  sufficient 
to  assure  the  continued  success  of  radio. 
It  is  impossible  to  venture  a  prediction 
as  to  its  future.  In  its  relationship  to 
jazz  music,  radio  seems  destined  to  be  an 
ally  and  when  such  a  condition  is  brought 
about,  jazz  will  only  be  one  of  many 
features  for  an  evening's  entertainment 
rather  than  occupying  the  spotlight  most 
of  the  time  as  it  does  now." 


REFLEX 

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f  |  >  readers  wish  to  show  their 
I  h  approval  of  RADIO  AGE'S 
stand  against  the  Radio 
Corporation  of  America,  they  can 
do  it  in  the  most  practical  way  by 
sending  in  $2.50  for  a  year's  sub- 
scription or  if  they  are  already  sub- 
scribers, urge  a  friend  to  subscribe. 
We  believe  the  fans  are  with  us. 
Address  Radio  Age,  Inc.,  500  N. 
Dearborn  St.,  Chicago,  111. 


*     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


71 


Radio  Technique  Now  Comes 
to  Fore 

By  Wilson  J.  Wetherbee, 
Director,  Westinghouse  Station  K YW 

TVTOW  comes  radio  technique.  Rather 
-L  ™  an  awe-inspiring  word,  this  tech- 
nique, but  all  in  all,  it  signifies  only  the 
tricks  of  the  broadcasting  business  which 
have  been  learned  by  those  who  pioneered 
the  development  of  the  new  art. 

After  all,  every  business  or  pastime 
must  have  its  technique.  The  laymen 
demand  technique,  for  without  it  they 
are  at  a  loss  to  explain  the  accomplish- 
ments of  those  engaged  in  any  occupa- 
tion. From  the  viewpoint  of  the  world, 
any  form  of  work  or  play  without  tech- 
nique is  work  or  play  of  no  importance. 
Consequently,  this  technique  is  altogether 
essential  even  in  radio. 

Radio  technique,  if  we  may  take  it  for 
granted  there  is  such  a  thing,  is  no  differ- 
ent fundamentally  than  the  technique 
involved  in  any  occupation.  It  consists 
primarily  in  knowing  what  to  do  over 
the  air.  More  important  still,  it  teaches 
what  not  to  do.  Therefore,  when  we 
say  a  certain  announcer  is  exceptionally 
good,  we  mean  he  is  a  good  radio  show- 
man; in  other  words,  he's  learned  the 
rudiments  of  broadcasting. 

The  Shining  Examples 

If  we  wish  to  catch  a  pretty  fair  glimpse 
of  this  more  or  less  elusive  technique  we 
have  only  to  consider  the  persons  who 
have  climbed  to  radio  stardom.  Y\  e 
think  first,  perhaps,  of  Wendell  Hall. 
Certainly  Hall  has  radio  technique.  Of 
course,  he  has  also  a  very  natural  talent 
which  he  developed  successfully  in  broad- 
cast channels.  In  other  words,  he  seized 
upon  his  natural  ability  to  entertain 
and  made  it  thoroughly  adaptable  to 
radio.  Hall  had  appeared  for  several 
years  before  clubs  and  on  the  vaudeville 
stage.  Then  came  the  radio.  Here  was 
a  new  problem.  His  audience  could  not 
see  him.  All  of  his  ability  and  personality 
must  be  put  into  his  voice.  Gestures 
and  pantomime  have  no  place  in  broad- 
casting. Hall  realized  this,  I  think  more 
completely  than  many  other  of  the  early 
radio  performers;  at  least  his  success 
indicates  that  he  did. 

All  of  the  radio  stars  today  have  this 
technique  business  pretty  well  in  hand. 
"Sen"  Kaney  is  liked  by  the  radio  public 
not  always  for  what  he  says,  but  for  the 
way  he  says  it.  The  same  is  true  of 
George  Hay,  Steve  Trumbull,  Eddie 
Borroff,  Roxie,  McNamee,  "Uncle  Bob" 
(Walter  Wilson),  and  a  score  of  other 
broadcast  announcers  who  have  climbed 
high  in  public  esteem. 

A  very  striking  example  of  radio 
technique  occurs  to  me.  I  remember 
well  about  two  years  ago  when  Jerry- 
Sullivan  first  came  into  prominence. 
Jerry  was  singing  at  various  Chicago 
stations  in  those  days.  Fans  were 
talking  about  his  remarkable  enunciation. 
Jerry,  I  believe,  was  one  of  the  first 
radio  artists  to  sing  softly  into  a  micro- 
phone. Often  when  he  was  appearing 
before  the  transmitter  it  was  impossible 
to  hear  him  in  the  rear  of  the  studio. 
Jerry  had  learned  another  trick  in  radio 
technique — the    necessity   for   clarity. 


CONDENSE 


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GET  MORE  VOLUME— GREATER  DISTANCE 
KNIFE-LIFE   SELECTIVITY 


The  Henninger  Aero  Coil  is  the  only 
tuning  inductance  and  is  the  only 
air  core  R.F.  transformer  which 
eliminates  all  resistances  and  conse- 
quent losses  which  broaden  tuning, 
decrease  volume  and  limit  distance 
range.  These  coils  will  give  you  a 
great  deal  more  volume,  greater  in- 
crease your  distance  range  and  give 
you  such  knife-like  selectivity  that 


you  can  tune  through  the  most  diffi- 
cult interference.  There  is  nothing 
else  like  the  Henninger  Aero  Coil. 
No  inductance  system  is  so  efficient. 
Build  a  tuned  R.F.  receiver  using 
this  wonder  inductance  system — or 
use  a  single  Aero-Coil  in  place  of  the 
tuning  inductance  in  your  present 
set.  $3.50  each  or  $10.50  the  set  of 
three  with  all  fittings. 


Write  for  free  illustrated  circular — "The  Prevention  of  Radio-Frequency  Losses."     Shoiv  how 
to  build  Henninger  Aero-Dyne  and  how  to  improve  any  kind  of  set  by  using  a  single  aero  coil. 

HENNINGER  RADIO  MFG.  CO.,  1772  Wilson  Ave.,  Dept.  28,  Chicago 


MARVELOUS  NEW 
AUDIO  TRANSFORMER 

adds  a  musical  qualityto  any  set  far 
beyond  anything  you  ever  heard 
before. 

KARAS  HARMONIK 
Amplifies  low,  middle  and  high 
tones — allto  the  same  big  volume, 
thus  eliminating  distortion.  Bringa 
out  the  vita  harmonica  and  over_ 
tones  of  music.  Price  $7.00.  Write 
Karas  Electric  Co.,   Dept.  58-93   4042  N.Roefcwefl  Si..  Chicago 


BA&ELfTE   PANELS 

used  by  95%  of  all  set  manufact- 
urers. Write  for  Booklet  31. 
ygv   BAKELITE  CORPORATION 

(oo)247  Park  Avenue,  New  York.  N.  Y. 
VSZ/  Chicago  Office:    636  West    22d  Street 


*     Tested  and  Approved  by  RADIO  AGE     ¥ 


72 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


"  'Worth  all  the 
Experienced  set- 
builder  can  put 
into  it." 

— N.  Y.  Telegram-Mail. 


'"PHOSE  advanced  experimenters 
•*-  who  have  built  the  "Telomonic 
III"  call  it  "the  most  sensitive  and 
selective  set  to  be  had."  It  should 
be!  For  when,  before  this,  have  you 
heard  of  3  stages  of  T.  R.  F. — per- 
fectly and  automatically  balanced, 
and  all  controlled  by  a  single  dial! 
And  when  have  you  heard  of  reflexing 
the  A.  F.  on  the  R.  F.  tubes?  And 
when,  also,  have  you  heard  of  run- 
ning a  6  or  7  tube  set  at  half  the  usual 
plate  current  consumption? 

All  this,  and  more,  is  now  being  done 
with  Teios.  And  all  the  essential  in- 
truments  are  in  the  new  Telos  Kit! 
Ask  your  dealer  for  a  Telos  demon- 
stration. It  will  open  up  new,  un- 
dreamed of  possibilities  for  you  in 
radio! 

DANZIGER- JONES,  Inc. 

Dept.  C  25  Waverly  Place,  N.  Y 


Danziger- Jones,     Inc., 
Dept.  C,  25  Waverly  Place, 
New   York,   N.    Y. 

Send  me  at  once  your  booklet   "The 
KIT  of  a  Thousand  Possibilities." 


Name 

Address.. 


._] 


Know  Before  You  Buy 

BEGINNING  with  this  issue,  RADIO  AGE  is  beginning  a  new  department,  to  be  known  as 
"Know  Before  You  Buy."  Every  month,  four  different  makes  of  manufactured  radio  sets 
will  be  described  in  detail  for  the  benefit  of  the  fan  about  to  purchase  a  radio  receiver. 

No  favorites  will  be  shown,  but  every  type  of  manufactured  set  will  be  described  from  month 
to  month,  to  enable  the  prospective  buyer  to  choose  wisely  and  economically,  according  to  the 
capacity  of  his  pocketbook.  The  manufacturers  of  the  particular  sets  described  support  all  the 
facts  given  in  the  description  of  their  receivers. 

In  listing  these  sets.  RADIO  AGE  will  attempt  to  present  every  conceivable  type  of  receiver 
from  the  simplest  crystal  to  the  most  elaborate  console  models.  Suggestions  from  readers  regarding 
this  new  department  will  be  welcomed,  and  manufacturers  are  invited  to  contribute  material  for 
these    columns. 


The  Zenith  Super  X 

The  Zenith  Radio  Receivers  are 
manufactured  by  the  Zenith  Radio 
Corporation,  332  S.  Michigan  Ave., 
Chicago.  The  Zenith  Super  X  Model 
shown  in  the  illustration  is  of  the 
non-regenerative  type  with  built-in 
twin  loudspeakers  and  horns. 

The  Super  Zenith  X  consists  of  six 
tubes  with  two  tuning  controls.  An 
outdoor  or  indoor  aerial  may  be  used. 
The  outstanding  features  of  this  new 
model  are  the  built-in,  patented  Super- 
Zenith  duo-loud  speakers,  which  are 
harmonically  synchronized  twin  speak- 
ers and  horns,  designed  to  reproduce 
both  high  and  low  pitched  tones  which 
otherwise  would  be  impossible  with 
single    unit    speakers. 

The  price  of  the  Zenith  Super  X 
without  tubes  and  batteries  is  S475. 
The  set  is  particularly  adaptable  to 
the  home,  as  it  is  of  a  beautiful  con- 
sole model  especially  designed  to  har- 
monize with    attractive  surroundings. 

Other  Zenith  models  range  in  price  from  S100  to  S355.  The 
Zenith  4R  sells  for  S100  and  the  3R  for  S175.  The  engineers 
of  the  Zenith  claim  their  sets  are  especially  designed  to  tune 
out  strong  local  stations  and  bring  in  distant  broadcasters  with 
local  volume. 


The  Pfanstiehl  Model  7. 


A  five-tube  Radio  Frequencv  receiver, 
manufactured  bv  the  Pfanstiehl  Radio 
Co.,  11  S.  LaSalle  St.,  Chicago,  111. 
This  set  is  known  at  the  Pfanstiehl 
"Overtone  Receiver,"  using  a  new  sys- 
tem of  tuned  radio  frequency  designed 
by  Carl  Pfanstiehl,  the  well  known  radio 
engineer  and  inventor.  Pfanstiehl's  sys- 
tem eliminates  oscillations  by  a  svstem 
which  is  said  to  cut  them  out  of  the 
circuit  entirely.  Tuning  and  operation 
of  the  set  are  quiet  as  well  as  simplified, 
there  being  three  dials,  each  of  which  is 
set  at  the  same  reading  when  a  set  is 
being   tuned. 


One  control  regulates  volume.  Dis- 
tortion is  also  eliminated.  The  dis- 
tinguishing feature  of  the  Model  7  is  the 
unique  station  finder,  which  enables 
even  the  greenest  novice  to  tune  in  a 
station.  All  that  is  necessary  is  to  know 
the  wavelength.  The  station  finder 
shows  the  numbers  on  the  dials  at  which 
to  turn  for  given  wavelengths. 

The  Model  7  makes  use  of  the  well 
known  Pfanstiehl  inductances,  and  brings 
in  distant  stations  at  will.  The  set  itself 
is  of  beautiful  finish.  The  price  is  $140 
without   accessories. 


THE  BEST  HOOKUPS  OF  THE  YEAR ! 

After  testing  and  studying  hookups  from  the  laboratories  of  Ameri- 
ca's renowned  engineers  in  the  radio  field,  RADIO  AGE  compiled 
the  best  in  the  RADIO  AGE  ANNUAL  for  1925.  You  will  find  nothing 
but  the  very  latest  in  radio  development  in  this  wonder  hookup 
book,  with  its  32-page,  original  BLUEPRINT  SECTION.  One  dollar 
a  copy.     Buy  yours  now  by  clipping  the  coupon  on  Page  80. 


■¥     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  April,  1925  The  Magazine  of  the  Hour 

uKnow  Before  You  Buy" 


73 


(Continued  from  opposite  page) 


The  Crosley  Trirdyn  Special 


A  new  design  for  the  famous  Crosley 
hookup,  manufactured  by  the  Crosley 
Radio  Corporation  of  363  Sassafras  St., 
Cincinnati,  Ohio.  The  Crosley  Trirdyn 
Special  is  exactly  the  same  as  the  regular 
Trirdyn,  except  that  it  is  encased  in  a 
more  elaborate  and  artistic  cabinet, 
finished  in  Adam  Brown.  The  new 
sloping  panel  is  used  in  the  beautiful 
cabinet,  making  an  artistic  piece  of 
furniture  for  any  home.  Ample  room 
is  provided  inside  the  set  for  both  "A" 
and  "B"  batteries.  The  price  without 
accessories  is  $65,  while  the  Trirdyn 
regular   is   S50. 

The  unique  Trirdyn  circuit  is  well 
known  throughout  the  radio  world. 
It  is  a  combination  of  Armstrong  re- 
generation,   radio    frequency    amplifica- 


tion and  reflexed  audio  amplification. 
Hundreds  of  communications  from  users 
of  the  Trirdyn  testify  to  the  Crosley 
Company's  claim  that  the  three-tube 
Crosley  sets  furnish  selectivity,  volume 
and  ease  of  operation  commonly  had 
with  five  or  even  six  tubes. 

Miraculous  distance  records  have  been 
achieved  with  the  Crosley  Trirdyn,  as 
well  as  the  other  Crosley  models,  which 
range  in  price  from  514.50  for  the  Crosley 
"50,"  a  one-tube  outfit,  to  the  elaborate 
"Special"   at  $65. 

Crosley  has  perfected  a  new  loud- 
speaker, shown  in  the  illustration,  which 
will  be  placed  on  the  market  soon.  It 
is  of  a  new  design  in  loudspeaker  con- 
struction and  is  reported  to  reproduce 
tones    with    unusual    clarity. 


The  Bremer-Tully  '"Nameless' 


A  five-tube  radio  frequency  receiver 
of  the  low  loss  type,  built  from  the  Bremer 
Tully  "Nameless"  kit,  manufactured 
by  the  Bremer-Tully  Mfg.  Company  of 
Chicago,  111.  While  this  set  is  not 
marketed  in  its  complete  form,  the  kit 
may  be  put  together  with  the  parts 
furnished  by  a  radio  fan  with  a  working 
knowledge  of  radio  construction. 

The  "Nameless"  is  noted  for  its  hair- 
line selectivity  on  all  distant  and  local 
stations;  its  remarkable  distance  quali- 
ties, volume  and  pure  tone.  Low  loss 
parts  are  used  throughout,  and  the  cir- 


cuit   is   of  a   reliable   tuned    R.  F.  type. 

The  Nameless  Kits  are  furnished  in 
two  forms,  with  complete  instructions 
for  assembly.  The  Kit  No.  3  contains 
3-circuit  transformers,  laboratory  con- 
densers, control  condenser  and  blue- 
prints. This  sells  for  $26.50,  while  the 
Nameless  Kit  No.  1  contains  the  3- 
circuit  transformers  only,  selling  for 
$10.50. 

The  Bremer-Tully  apparatus  is  of 
course  recommended  throughout  in  the 
construction  of  the  "Nameless,"  but 
this  only  adds  to  the  set's  efficiency. 


Where   The   DX   Fans   Congregate. 

Are  you  a  reader  of  RADIO  AGE'S  popular  "Pickups  and  Hookups" 
section?  Turn  to  the  Pickups  pages  this  month  and  read  about 
our  drive  to  determine  the  "Chief  Dial  Twister."  We're  out  to  get 
DX  records,  so  if  you  have  been  logging  the  distant  broadcasters 
lately,  send  in  your  list  and  maybe  you'll  be  counted  as  one  of  "Who's 
Who  in  DX-Land"  in  the  May  RADIO  AGE.  Also,  another  record- 
breaking  portable  receiver  for  the  outdoor  fan  will  be  published  in 
the  May  issue. 


Biggest  dollars 
worth  in 

RADIO 


Compiled  by  HARRY  F.  DART,  E.E. 

Formerly    with    the   Western    Electric    Co.,    and 

U.  S.  Army  Instructor  of  Radio 

Technically  edited  by  F.  H.  DOANE 

514  PAGES— ONLY  $1 

ONE  of  the  most  complete  books  of  its 
kind  ever  published.  Written,  com- 
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of  national  reputation.  Packed  with  con- 
cise, sound  information  useful  to  every 
radio  fan — from  beginner  to  veteran  hard- 
boiled  owl.     Contents — 

Electrical  terms  and  circuits,  antennas, 
batteries,  generators  and  motors,  elec- 
tron (vacuum)  tubes,  most  receiving 
hook-ups,  radio  and  audio  frequency 
amplification,  broadcast  and  commercial 
transmitters  and  receivers,  wave  meters, 
super-regeneration,  codes,  license  rules. 
Many  other  features. 

Just  mail  the  coupon  printed  below  with  a  dollar 
bill  and  your  name  and  address,  and  we  will  send 
you  this  514-page  I.  C.  S.  Radio  Handbook  or  any 
of  the  other  I.  C.  S.  Handbooks  that  you  want  by 
return  mail.     Money  back  if  not  satisfied. 


International   Correspondence  Schools 
Box  8785-C,  Scranton,  Penna. 
I  enclose  $  ,  for  which  send  me,  post-paid, 

the  Handbooks  marked  X.  at  SI  each.  It  is  under- 
stood that  if  I  am  not  entirely  satisfied  I  may 
return  them  within  five  days  and  you  will  refund 
my  money. 

□  RADIO   HANDBOOK,  $1 

□  Automobile    Handbook  SI 

□  Electrical    Handbook - $1 

fj  Chemistry   Handbook 51 

□  Pharmacy    Handbook SI 

D  Traffic    Handbook  51 

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□  Machine     Shop     Handbook  §1 

□  Salesman's     Handbook 51 

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□  Bookkeeper's    Handbook SI 

Q  Civil    Engineer's     Handbook 51 

Q  Steam  Engineer's   Handbook  $1 


Make  8100  Weekly  -sell  RADIO 

Demonstrate  Once  —  Results  Mean  Sure  Sale 
Coast  to  coast ,lo  west  prices,at trac- 
tive four-tube  instrument  $39.50. 
Big  commission  to  you.  Exclusive 
^territory  to  proven  salesmen.  Ter- 
Iritory  going  fast,  write  today  for 
flarge  illustrated  book  No.  100. 
"Don't  fail  to  name  your  county. 
OZARKA,  Inc. 

629  Washington  Blvd.  Chicago,  (II. 


*     Tested  and  Approved   by  RADIO   AGE     # 


74 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA 

KDLR 

KDPM 

KDPT 

KDYL 

KDYM 

KDZB 

KDZE 

KDZI 

KFAD 

KFAE 

KFAF 

KFAJ 

K.FAN 

KFAU 

KFAW 

KFBB 

KFBC 

KFBE 

KFBG 

KFBK 

KFBL 

KFBU 

KFCB 

KFCC 

KFCF 

KFCL 

KFCP 

KFCZ 

KFDD 

KFDH 

KFDJ 

KFDM 

KFDX 

KFDY 

KFDZ 

KFEC 

KFEK 

KFEL 

KFEQ 

KFER 

KFEY 

KFFP 

KFFR 

KFFV 

KFFY 

KFCB 

KFCC 

KFGD 

KFGH 

KFGQ 

KFGX 

KFHA 

KFHH 

KFHJ 

KFHL 

KFHR 

KFI 

KFIF 

KFIO 

KFIQ 

KFIU 

KFIX 

KFIZ 

KFJB 

KFJF 

KFJI 

KFJL 

KFJM 

KFJR 

KFJX 

KFJY 

KFJZ 

KFKA 

KFKB 

KFKQ 

KFKU 

KFKV 

KFKX 

KFLA 

KFLB 

KFLD 

KFLE 

KFLP 

KFLR 

KFLU 

KFLV 

KFLX 

KFLZ 

KFMB 

KFMQ 

KFMR 

KFMT 

KFMW 

KFMX 

KFNF 

KFNG 

KFNJ 

KFNL 

KFNV 

KFNY 

KFNZ 

KFOA 

KFOC 

KFOD 

KFOJ 

KFOL 

KFON 

KFOO 

KFOP 

KFOR 

KFOT 

KFOU 

KFOX 

KFOY 

KFPB 

KFPG 

KFPH 

KFPL 

KFPM 

KFPR 

KFPT 

KFPV 

KFPW 

KFPX 

KFPY 

KFOA 

KFQB 

KFQC 

KFQD 

KFQE 

KFQG 

KFQH 

FFQM 

KFQN 

KFQP 

KFOR 

KFQT 


Westinghouse  Electric  4  Mfg.  Co East  Pittsburgh  309  KFQU 

Radio  Electric  Co Devils  Lake.  N.  D.  231  KFQW 

Westinghouse  Electric  4  Mfg.  Co Cleveland,  Ohio  270  KFQX 

Southern  Electrical  Co San  Diego.  Calif.  244  KFQY 

Newhouse  Hotel Salt  Lake  City,  Utah  250  KFQZ 

Savoy  Theatre San  Diego.  Calif.  280  KFRJ 

Frank  E.  Siefert Bakersfield.  Calif.  240  KFRM 

Rhodes  Department  Store Seattle.  Wash.  270  KFRN 

Electric  Supply  Co Wenatchee,  Wash.  360  KFRO 

McArthur  Bros.  Mercantile  Co Phoenix,  Ariz.  360  KFRU 

State  College  of  Washington Pullman,  Wash.  348  KFRW 

Western    Radio   Corporation Denver,  Colo.  278  KFRX 

University   of  Colorado Boulder.  Colo.  360  KFRY 

University    of    Idaho Moscow.    Ida.  230  KFRZ 

Boise   High   School Boise.  Idaho  271  KFSG 

The  Radio  Den  (W.  B.  Ashford) Santa  Ana,  Calif.  280  KFS Y 

F.  A.  Buttrey  &  Co Havre,  Mont.  360  KFUJ 

W.  K.  Azbill San  Diego.  Calif.  278  KFUL 

Horn  &  Wilson's  "Rarlioland" San  Luis  Obispo,  Calif.  218  KFUM 

First  Presbyterian   Church Tacoma.   Wash.  250  KFUO 

Kimball-Upson  Co Sacramento,  Calif.  283  KFUP 

Leese  Bros Everett,  Wash.  224  KFUQ 

The  Cathedral Laramie,  Wyo.  283  KFUR 

Nielson  Radio  Supply  Co Phoenix.  Ariz.  238  KFUS 

The    First   Congregational    Church Helena.    Mont.  248  KFUT 

Frank  A.  Moore Walla  Walla.  Wash.  256  KFUU 

Leslie  E.  Rice Los  Angeles,  Cal.  236  KFUY 

Ralph    W.    Flygare Ogden  .  Utah  360  KFUZ 

Omaha  Central  High  School Omaha  .Nebr.  258  KFVF 

St.  Michaels  Cathedral Boise.  Idaho  252  K.FWA 

University  of  Arizona Tuscon,  Ariz.  368  KFWB 

Oregon  Agricultural  College Corvallis.  Oreg.  254  KFWC 

Magnolia    Petroleum    Co Beaumont.    Tex.  315  KGB 

First  Baptist  Church Shreveport,  La.  360  KGO 

South  Dakota  State  College Brookings.  S.  Dak.  360  KGU 

Harry  O.  Iverson Minneapolis.  Minn.  231  KGW 

Meier  A  Frank  Co Portland,  Oreg.  248  KGY 

Augsbury    Seminary Minneapolis.    Minn.  261  KHJ 

Winner  Radio  Corp Denver,  Colo.  254  KHQ 

J.  L.  Scroggin Oak.  Nebr.  268  KJQ 

Auto  Electric  Service  Co Fort  Dodge.  Iowa  231  KJR 

Bunker  Hill  4  Sullivan  Mining  and  Concentrating  Co Kellogg.  Idaho  233  KJS 

First  Baptiat  Church Moberly.  Mo.  266  KLS 

Nevada  State  Journal   (Jim  Kirk) Sparks.  Nev.  226  KLX 

Graceland  College Lamoni.  Iowa  280  KLZ 

Pincus     4     Murphey     Music     House Alexandria.     La.  275  KMJ 

Heidbreder   Radio   Supply   Co Utica.   Neb.  224  K.MO 

Louisiana  State  Llniversity Baton  Rouge.  La.  254  KNT 

Chickasha  Radio  4  Electric  Co Chickasba.  Okla.  248  KNX 

Leland  Stanford   University Stanford  University.  Calif.  273  KOA 

Crary  Hardware  Co Boone.  Iowa  226  KOB 

First   Presbyterian    Church Orange.  Tex.  250  KOP 

Western  State  College  of  Colorado Gunnison.  Colo.  252  KPO 

Ambrose  A.  McCue Neah  Bay.  Wash.  261  KPPC 

Fallon  &  Co Santa  Barbara .  Calif.  360  KQV 

Penn     College Oskaloosa.     Iowa  240  KQW 

Star  Electric  4  Radio  Co Seattle.  Wash.  283  KRE 

E.  C.  Anthony,  Inc Los  Angeles,  Calif.  468  KSAC 

Benson   Polytechnic    Institute Portland,   Oregon  248  KSD 

North  Central  High  School Spokane.  Wash.  252  KTHS 

First   Methodist   Church Yakima.  Wash.  242  KTW 

Alaska  Electric  Light  &  Power  Co Juneau.  Alaska  226  KUO 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints. Independence.  Mo.  240  KUOM 

Daily  Commonwealth  and  Oscar  A.  Huelsman Fond  du  Lac.  Wis.  273  KWG 

Marshall  Electrical  Co Marshalltown.  Iowa  248  KWH 

National'Radio  Manufacturing  Co Oklahoma  City.  Okla.  252  KYQ 

Liberty  Theatre  (E.  E.  Marsh) Astoria.  Oreg.  252  KYW 

Hardsacg  Manufacturing  Co Ottumwa.  Iowa  242  KZM 

University  of   North   Dakota Grand   Forks.   N.  Dak.  280  WAAB 

Ashley  C.  Dixon  A  Son Stevensville.  Mont,  (near)  258  WAAC 

Iowa  State  Teacher's  College Cedar  Falls.  Iowa  280  WAAD 

Tunwall  Radio  Co Fort  Dodge.  Iowa  246  WAAF 

Texas  National  Guard.  One  hundred  and  twelfth  Cavalry.  Fort  Worth  Texas  254  WAAM 

Colorado  State  Teachers  College Greeley.  Colo.  273  WAAN 

Brinkley-Jones    Hospital   Association Milford.   Kans.  286  WAAW 

Conway  Radio  Laboratories  (Ben  H.  Woodruff) Conway,  Ark.  250  WABA 

The    University    of    Kansas Lawrence.    Kans.  275  WABB 

F.  F.  Gray Butte.  Mont.  283  WABH 

Westinghouse  Electric  4  Manufacturing  Co Hastings.  Nebr.  288  WABI 

Abner  R.  Willson Butte.  Mont.  283  WABL 

Signal  Electric  Manufacturing  Co Menominee.  Mich.  248  WABM 

Paul  E.  Greenlaw Franklinton.  La.  234  WABN 

National  Educational  Service Denver.  Colo.  268  WABO 

Everett  M.  Foster Cedar  Rapids.  la.  256  WABQ 

University  of   New   Mexico Albuquerque.  New  Mexico  254  WABR 

Rio  Grande  Radio  Supply  House San  Benito.  Texas  236  WABU 

Rev.  A.  T.  Frykman Rockford.  111.  229  WABW 

George  Roy  Clough Galveston.  Tex.  240  WABX 

Atlantic   Automobile    Co Atlantic.   la.  273  WABY 

Christian  Churches Little  Rock,  Ark.  254  WABZ 

University  of   Arkansas Fayetteville,  Ark.  299  WAFD 

Morningside  College ; Sioux  City.  Iowa  261  WAHG 

Dr.  George  W.  Young Minneapolis.  Minn.  231  WAMD 

M.  G.  Sateren Houghton.  Mich.  266  WBAA 

Carleton  College Northfield.  Minn.  336  WBAC 

Henry  Field  Seed  Co Shenandoah  .Iowa  266  WBAH 

Wooten's   Radio  Shop Coldwater.  Miss.  254  WBAN 

Central  Mo.  Ststte  Teachers  College Warrensburg.  Mo.  234  WBAO 

Radio  Broadcast  Ass'n Paso  Robles.  Calif.  240  WB AP 

L.  A. "Brake  Battery  snd  Radio  Supply  Shop 8anta  Rosa.  Calif.  234  WBAV 

Montana   Phonograph   Co Helena.   Montana  261  WBAX 

Royal  Radio  Company Burlingame.  Calif.  231  WBAY 

Rhodes   Department  Store ,.  .Seattle  .Wash.  384  WBBD 

First   Christian    Church Whittier,  Calif.  236  WBEG 

Radio  Shop Wallace. Idaho  224  WBBH 

Moberly  High  8chool  Radio  Club Moberly.  Missouri  246  WBBL 

Leslie  M.  Schafbush Marengo.  Iowa  234  WBBM 

Echophone  Radio  Shop Long  Beach.  Calif.  234  WBBN 

Latter  Day  Saints  University Salt  Lake  City.  Utah  261  WBBP 

Rohrer       Elec.        Co Marshfield        Ore.  240  WBBR 

David  City  Tire  4  Electrio  Co David  City.  Nebraska  226  WBBS 

College   Hill  Radio   Club Wichita,   Kansas  231  WBBU 

Hommel   Mfg.   Co Richmond,  Calif.  254  WBBV 

Board  of  Education,  Technical  High  School Omaha,  Nebraska  248  WBBX 

Beacon  Radio  Service St.  Paul.  Minn.  226  WBBY 

Edwin    J.    Brown Seattle,   Wash.  224  WBBZ 

Garretson  and   Dennis Los   Angeles,  Calif.  238  WBCN 

Harold  Chas.  Mailande.' Salt  Lake  City.  Utah  242  WBDC 

C.    C.  Baxter Dublin,  Texas  242  WBES 

The  New  Furniture  Co Greenville,  Texas  242  WBGA 

Los  Angeles  Co.  Forestry  Dept Los  Angeles.  Calif.  231  WBR 

Cape     4     Johnson Salt     Lake     City.  Utah  268  WBRE 

Heintz  A   Kohlmoos.  Inc San   Francisco.  Calif.  236  WBS 

St.  Johns  M.   E.   Church _ Carterville,  Mo.  268  WBT 

First    Presbyterian    Church Pine    Bluff,   Ark.  242  WBZ 

Symons  Investment  Co Spokane.  Wash.  283  WCAD 

The  Principia St.   Louis.  Mo.  264  WCAE 

The  Searchlight  Publishing  Co Fort  Worth,  Tex.  221  WCAG 

Kidd  Brothers  Radio  Shop Taft,  Calif.  258  WCAH 

Chovin  Supply  Co Anchorage.  Alaska  207  WCAJ 

Dickenson-Henry   Radio  Laboratories Colorado  Springs  .  Colo.  224  WCAL 

Southern  Calif.  Radio  Ass'n Lo8  Angelas  ,  Calif.  226  WCAO 

Radio    Service    Co Burlingame  .Calif.  231  WCAP 

Texas   Highway  Bulletin Austin.  Tex.  268  WCAR 

Thrd  Baptist  Church Portland.  Ore.  283  WCAS 

G.  S.    Carson,   Jr Iowa    City.    la.  284  WCAT 

Walter  LsFarette  F":« Oklahoma   City,   Okla.  220  WCAU 

Texas   National   Guard Denison.   Texas  252  WCAV 


W.  Riker Holy  City.  Calif.  25J 

C.  F.   Knierim North  Bend.  Wash.  248 

Alfred    M.    Hubbard Seattle,    Waah.  231 

Farmers  Staw  Bank Belden  ,  Neb.  273 

Taft  Radio  Co Hollywood.  Calif.  240 

Guy  Simmons.  Jr Conway ,  Ark.  250 

James   F.   Boland Fort  Sill,    Okla.  263 

M.  Laurence  Short Hanford.  Calif.  224 

Curtis   Printing   Co Ft.   Worth,   Tex.  246 

Okmulgee  Disfr.  Oil  and  Gas  Assn Bristow.  Okla.  381 

United  Churched  of  Olympia Olympia,  Waah.  220 

J.    Gordon    Klemgard Pullman.    Wash.  217 

NowMexicoCollegeof  Agriculture  and  Mechanic  Arts,    State  College.   N.   M  266 

The  Electric  Shop Hartington.  Neb.  222 

Angelua  Temple Loa  Angeles,  Calif.  27$ 

The  Van  Blaricon  Co Helena, Mont.  261 

Hoppert  Plumbing  and  Heating  Co Breckenridge.  Minn.  242 

Thomas  Goggan  A  Bros.  Music  Co Galveston.  Tex.  258 

W.  D.  Corley Colorado  Springs,  Colo.  242 

Concordia    Seminary St.    Louis,    Mo.  549 

Fitzsimmons    General    Hospital Denver,    Col.  234 

Julius  Brunton  and  Sons  Co •. San  Francisco,  Cal.  234 

H.  W.  Peery  and  C.  Redfield Ogden,  Utah  224 

Louis    L.    Sherman Oakland,    Calif  233 

University  of  Utah Salt  Lake  City,   Utah 

Colburn  Radio  Labs San  Leandro.  Cal.  234 

Irvine   M.   Bouchard Butte.    Mont.  254 

Y.   M.   C.  A Virginia,    Minn.  248 

Clarence     B.     Juneau Hollywood.     Cal.  208 

Browning  Bros.  Co Ogden,  Utah  214 

Warner     Bros Hodywood,      Cal.  252 

L.  E.  Wall  and  C.  S.  Myers Upland.  Cal.  211 

Tacoma  Daily  Ledger Tacoma,  Waah.  252 

General  Electric    Co Oakland.    Calif.  361 

Marion  A.  Mulrony Honolulu,  Hawaii.  Waikiki  Beach  360 

Portland  Morning  Oregonian Portland,   Oreg.  491 

St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy,  Wash.  258 

Times-Mirror    Co Los    Angeles.    Calif.  405 

Louis    Wasmer Seattle,    Wash.  273 

C.  O.  Gould Stockton.    Calif.  273 

Northwest  Radio  Service  Co Seattle,  Wash ,  405 

Bible   Institute  of  Los  Angeles.   Inc Los  Angeles.   Calif.  252 

Warner  Brothers   Radio  Supplies  Co Oakland.   Calif.  360 

Tribune  Publishing  Co Oakland,  Calif.  508 

Reynolds  Radio  Co Denver,  Colo.  28J 

San  Joaquin  Light  A  Power  Corp Fresno,  Calif.  248 

Love  Electrio  Co Tacoma,  Wash.  250 

Walter  Hemrich Kukah  Bay.  Alaska  263 

Los  Angeles  Evening  Express Los  Angoles. Calif.  337 

General  Electric  Co Denver  Col.  323 

New  Mexico  College  of  Agriculture  4  Mechanic  Arts.  .State  College,  N.Mex.  348 

Detroit  Police  Department Detroit.  Mich.  286 

Hale  Bros San  Francisco.  Calif.  428 

Pasadena    Presbyterian    Church Pasadena.    Cal.  229 

Doubleday-Hill  Electric   Co...; Pittsburgh.  Pa.  270 

Charles  D.  Herrold San  Jose,  Calif.  210 

V  C  Battery  A  Electric  Co .Berkeley.  Calif.  275 

Kansas  State  Agricultural  College Manhattan.  Kans.  341 

Post  Dispatch  (Pulitzer  Pub.  Co.) St.  Louis.  Mo.  545 

New  Arlington  Hotel  Co not  Springs.  Ark.  375 

First  Presbyterian   Church Seattle,  Wash.  360 

Examiner  Printing  Co San  Francisco,  Calif.  246 

State  University  of  Montana Missoula,  Montana  244 

Portable  Wireless  Telephone  Co Stockton,  Calif.  360 

Los   Angeles   Examiner Los  Angeles.    Calif.  360 

Electric    Shop Honolulu,    Hawaii  270 

Westinghouse  Electrio  4  Mfg.  Co Chicago.  111.  535 

Preston   D.  Allen Oakland.    Calif.  360 

Valdemar    Jensen New    Orleans.    La.  268 

Tulane  Univer.ity New  Orleans.  La.  275 

Ohio   Mechanics   Institute Cincinnati.  Ohio  248 

Chicago  Daily  Drovers  Journal Chicago.  III.  286 

I.  R.  Nelson  Co Newark,  N.  J.  263 

University  of  Missouri Columbia.  Mo.  254 

Omaha  Grain  Exchange Omaha,   Nebr.  286 

Lake  Forest  University Lake  Forest,  III  227 

Harrisbura  Sporting  Goods  Co Harrisburg,  Pa.  266 

Lake  Shore  Tire  Co Sandusky,  Ohio  240 

Bangor  Railway  A  Electric  Co Bangor.  Me.  240 

Connecticut  Agricultural    College Storrs,    Conn.  283 

F.  A.  Doherty  Automotive  and  Radio  Equipment  Co Saginaw,  Mich.  254 

Ott  Radio,  Inc LaCrosse,  Wis.  244 

Lake  Avenue  Baptist  Church Rochester.  N.  Y.  283 

Haverford  College.  Radio  Club Haverford.  Pa.  261 

Scott  High  School.  N.  W.  B.  Foley Toledo.  Ohio  270 

Victor  Talking  Machine  Co Camden.  N.  J.  226 

College  of  Wooster Wooster.  Ohio  234 

Henry  B.  Joy lit,  Clemens.  Mich.  270 

John  Magaldi.  Jr Philadelphia.  Pa.  242 

Coliseum  Place  Baptist  Church New  Orleans.  La.  263 

Albert    B.    Parfet    Co Port    Huron.    Mich.  233 

A.  H.   Grebe  A   Co Richmond   Hill.   N.  Y.  315 

Hubbard  and  Co Minneapolis.  Minn.  244 

Purdue  University W.   Lafayette.  Ind.  283 

Clemson  Agric.  College Clemson  College.  S.  C.  331 

The  Dayton  Co Minneapolis,  Minn.  417 

Wireless  Phono  Corp Paterson.  N.  J.  244 

James     Millikin     University Decatur.    111.  350 

Wortham-Carter  Publishing  Co.   (Star  Telegram) Fort  Worth,  Tex.  476 

Erner  &  Hopkins  Co Columbus.  Ohio  232 

John  H.  Stenger,  Jr Wilkes-Barre,  Pa.  254 

Western  Electric  Co New  York.  N.  Y.  492 

Barbey  Battery  Service Reading,  Pa.  23  i 

Irving  Vermilya Mattapoisett.  Mass.  245 

J.  Irving  Bell Port  Huron.  Mich.  248 

Grace  Covenant  Presbyterian   Church Richmond.   Va.  283 

H.   Leslie   Atlass Chicago.  111.  226 

Blake.  A.  B Wilmington.  N.  C.  275 

Petoskey    High    School Petoskey,  Mich.  246 

Peoples   Pulpit  Asso Rossville,   N.   Y.  273 

First    Baptist    Church New    Orleans. La.  252 

Jenks    Motor    Sales    Co Monmouth  ,  111.  224 

Johnstown  Radio  Co Johnstown.  Pa.  245 

Ruffner     Junior     High     School Norfolk. Va.  222 

Washington  Light  Infantry  Co.  "B"  UStS  lnf Charleston.  S.  C.  268 

Noble  B.  Watson Indianapolis.  Ind.  227 

Foster  4  McDonald Chicago.   111.  266 

Baxter    Laundry    Co Grand     Rapids.     Mich.  256 

Bliss  Electrical  School Takoma  Park.  Md.  222 

Jones  Elec.  4  Radio  Mfg.  Co Baltimore.  Md.  254 

Pennsylvania  State  Police Butler.  Pa.  236 

Baltimore      Radio      Exchange Wilkes-Barre,  Pa.  231 

D.  W.  May.  Inc Newark.  N.  J.  252 

Southern    Radio    Corp Charlotte.    N.    C.  275 

Westinghouse     E.     &     M.     Co Springfield,     Mass.  333 

St.  Lawrence  University Canton,  N.  Y.  280 

Kaufmann  A  Baer  Co Pittsburgh  .  Pa.  461 

Clyde  R.  Randall New  Orleans.  La.  268 

Entrekin  Electric  Co Columbus.  Ohio  234 

Nebraska  Wesleyan  University University  Place.  Nebr.  283 

St.  Olaf  College    Northfield.  Minn.  336 

Sanders  4  Stayman  Co Baltimore.  Md.  275 

Chesapeake  4  Potomac  Telephone  Co Washington.  D.  C.  468 

Alamo  Radio  Electric  Co San  Antonio.  Tex.  263 

W.  H.  Dunwoody  Industrial  Institute Minneapolis,  Minn.  280 

State  College  of  Mines Rapid  City .  S.  Dak.  240 

Durham    4    Co Philadelphia  .  Pa.  278 

J.  C.  Dice  Electric  Co Little  Rock.  Ark.  253 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hoar 


75 


CLASSIFIED  ADVERTISEMENTS 


Don't  overlook  the  value  of 
RADIO  AGE'S  classified  adver- 
tisements. Many  such  messages 
have  paved  the  way  to  independent 
incomes. 

The  classified  advertising  rates 
are  but  ten  cents  per  word  for  a 
single  insertion.  Liberal  discounts 
are     allowed     on     three,     six     and 


twelve  -  time  insertions,  of  five,, 
fifteen  and  thirty  per  cent,  re- 
spectively. Unless  placed  through 
an  accredited  advertising  agency, 
cash  should  accompany  all  orders. 
Name  and  address  must  be  in- 
cluded at  foregoing  rates  and  no 
advertisement  of  less  than  ten 
words   will   be   accepted. 


AGENTS  WANTED 


RADIO— Jo 


sales  organization  and  make  big 
money.  We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers. Widener  of  Kansas  City  makes  $150.00 
weekly.  You  can  do  as  well  or  better.  Write  today 
for  catalog,  and  discounts.  Name  your  county.  Wave- 
land  Radio  Company,  Div.  52,  1027  No.  State  St.,  Chi- 
cago,  111. 

MANUFACTURER'S  AGENT  calling  on  Radio-Elec- 
trical Jobbers,  Chicago  and  vicinity,  has  opening  for  3 
additional  lines  carrying  volume  business,  as  we  cater 
to    large    jobbers.        Edelstein,    1804    McCormick    Bid., 


HELP  WANTED 

RADIO  SALESMEN  and  SET  BUILDERS— We  need 
you  and  you  need  us.  If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  III. 


MANUFACTURING  FACILITIES 

AN  OLD  AND  WELL  ESTABLISHED  MANUFACTUR- 
ING  COMPANY  IN  THE  MIDDLE  WEST  WITH  LARGE 
WELL  EQUIPPED  PLANTS  AND  UNUSUAL  FINAN- 
CIAL RESOURCES,  DESIRING  TO  ENTER  THE  RADIO 
FIELD  WILL  CONSIDER  THE  MANUFACTURE  AND 
SALE  OF  RADIO  SETS  OR  DEVICES  OF  OUTSTAND- 
ING AND  UNUSUAL  MERIT  ON  A  ROYALTY  BASIS. 
ADDRESS  BOX  1A.  RADIO  AGE. 


RADIO 


A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  111. 


Standard  soderle 


adio  Jacks.  Binding  post  attach- 
:uit.  One  dollar  bill.  Postpaid. 
New   Paltz.    New    York,    N.    Y. 


100  VOLT   EDISON  TYPE 
down.        Parts     and     plans- 
Mfg.,  2937  W.  Lake,  Chicago. 


FOR  SALE— 3  Pfanstiehl  tuning  units.  3  Cardwell  Con- 
densers, 1  Bradleyometer,  2  Bradleystats.  All  goods 
New.     Earl  Price,  Lodi,  Wis. 


RADIO  CIRCUITS 


BLUEPRINTS — Make 


et     fr, 


original  and  up-to-the-minute  blueprints.  The  follow- 
ing are  merely  three  of  a  choice  of  almost  one  hundred 
different  types: 

HT-1-3— Five  tube  neutrodyne — 50c. 

FB-6 — Three-honeycomb  regenerative — SSc. 

D10-4 — Diode  single  circuit — 25c. 

All  three  of  above,  for  $1.00. 

These  tested  blueprints  are  all  made  up  in  easily 
read  circuit  drawings.  MIDLAND  PRODUCTS  COM- 
PANY, 1413  Hood  Ave.,  Chicago,  111.  Ask  for  our  com- 
plete list,  No.  R-31. 

RADIO  DEALERS 


DEALERS— Write  fo; 
Radio  Merchandise. 
Dept.  D,  1830  Wilson 


■  our  illustrated  catalog  of  reliable 
Rossiter-Manning    Corporation, 
Ave.,  Chicago,  111. 


STAMPS  AND  COINS 


Wa 


Is 


158    Genuine    Foreign    Stamps.       Mexico 

Venezuela,    Salvador   and    India    Service. 

China,    etc.,    only    5c.      Finest    approval    sheets,    50    to 

60   per   cent.      Agents   Wanted.      Big    72-p.    Lists    Free. 

We    Buy    Stamps.       Established    20    Years.       Hussman 

Stamp  Co.,  Dept.  152,  St.  Louis,  Mo. 


WANTED 


Hollbrook,  Ariz 


set    RADIO    AGE 
_,   November,   1923,    is 
Advise  price.     Lloyd  C.  Hen 


WRITERS 


NEW  WRITERS  WANTED— Articles,  stories,  poems, 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No.  bunk.)  NOT  A  CORRE- 
SPONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
azines. Send  self  addressed  envelope  for  list  of  100 
subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Los 
Angeles,  Calif. 

BATTERY   COMPOUND 

LIGHTNING  STRANGE  BATTERY  COMPOUND- 
Charges  discharged  batteries  instantly.  Eliminates 
old  method  entirely.  Gallon  free  to  agents.  Light- 
ning Co..  St.  Paul,  Minn. 


RADIO  TUBES 


AGENTS 


90c  an  hour  to  advertise  and  distribute  samples  to  con- 
sumer. Write  quick  for  territory  and  particulars. 
American  Products  Co.,  2130  American  Building,  Cin- 
cinnati, Ohio. 

Man  wanted  for  this  territory  to  sell  wonderful 
value  men's,  women's.  Children's  shoes  direct,  sav- 
ing consumer  over  40 % .  Experience  unnecessary. 
Samples  supplied.  Big  weekly  permanent  income. 
Write  today  Tanners  Mfg.  Co.,  1334C.  St.,  Boston,  Mass. 

MR" 


B"  BATTERIES 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parts  and  plans— complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake,  Chicago. 


RADIO  OFFERS 


15  to  25  per  cent  discount  on  nationally  adverti: 
and  parts.  Every  item  guaranteed.  Tell  us  youi 
IMPERIAL  RADIO  COMPANY,  Delaware,  Ohio. 


JOIN  THE   RADIO  Parts  Exchange  Club.      Your  parts 
inspected   (Fee  25c),   and  exchanged   for   the   parts   you 
need.     What    have    you;    what    parts    do    you    require? 
Write  us  for  details. 
The  Radio  Parts  Exchange  Club,   112  So.   Homan  Ave., 


Chi, 


RADIO  CIRCUITS 

SPECIAL  FOR  APRIL 
The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne,  fully 
illustrated,  and  RADIO  AGE,  for  $2.50.      Price  of  Book- 
let alone  is  50c.      Send  check,  currency  or  money  order 
to  RADIO  AGE,  500  N.  Dearborn  Street,  Chicago. 


VOCATIONS 


Make    Big    Money.      Safe    and    Lock    Expert. 
Strong,  3800  Lan  Franco  St.,  Los  Angeles,  Calif. 

RADIO  SUPPLIES 


Wayne 


Ten  per 
from  cond 
fore 


nt  discount  on  all  standard  radio  parts, 
sers  to  transformers  to  tubes,  etc.  Send 
ir  latest  price  list,  with  special  bargains  on  Static- 
nators,  portable  loud  speakers,  Radiotrons,  Ger- 
man silver  wire,  etc.  RADIOGRAPH  LABORATORIES. 
1234  Rosemont  Ave.,  Dept.  4,  Chicago,  III. 


MANUSCRIPTS 

ful   radio  hook-up  and  would  like 
various   radio    publications,   etc., 
.ominal  cost.      Don't  be  held  back 
bility  to  put  your  technical  ideas 
elp  shape  your  technical  construe- 
that  they  will  BE  SOLD  at  BIG  MONEY 
i  magazines  and  radio  newspaper  sup- 
give     you     free     criticism     and    writers* 
_rticle  is  sold.     Write  for  free  descriptive 
WILLIS  ARNOLD  AND  ASSOCIATES.      210  E. 


If  you  hav 
to    market 

'it  a"m 

'tional 

he! 
nger 
Jrds 

by  th 

We  v. 

les  so  t 

to  the 
pleme 

its?' 

radio 

We    s 

folder. 

WILLIS 

.Chic 


TRY  US! 

Radio  Dealer: 

We  are  exclusive 
Radio  Jobbers 
and  DO  NOT 
RETAIL. 

Howard  —  Crosley 

Liberty — Day-  Fan 

Receiving  Sets 

Complete  line  of  parts. 
We    Sell    to    Dealers    Only. 

Write  for  Catalog. 

TAY  SALES  CO. 

6  N.  Franklin  St.,   Chicago 


V A  in  RADIO 

p0!:.   Should  Write  for 
■J:    .  lV  ihisFREERddioBook 


The  Greatest  Bargain 
Catalog  published.  Chock 
full  of  thousands  of  Radio  Bargains 
at  the  lowest  prices  to  be  found  any- 
where in  the  United  States. 
Parts,     Supplies,     Sets,     Parts    of 

Sets,     Latest    Circuits. 
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76         RADIO  AGE/or  April,  1925 


The  Magazine  of  the  Hour 


WCAX      University  of  Vermont Burlington  ,  Vt.  250  WHBC 

WCAZ       Carthage    College Carthage  ,  111.  246  WHBD 

WCBA       Charles  W.  Heibachm Allentown,  Pa.  280  WhBF 

WCBC     University  of  Michigan :  .  .Ann  >-rbor,  Mich  280  WHBG 

WGBD     Wilbur  C.  Voliva Zion.  III.  344  WHBH 

WCBE       Uhalt  Radio  Co New  Orleans,  La.  263  WHbl 

WCBF       Paul  J.  Miller Pittsburgh ,  Pa.  236  WHK 

WCBG      Howard  S.  Williams  (Portable) Pascagoula.  Mias.  268  WHN 

WCBH       University     of     Miss Oxford,     Miss.  242  WHO 

WCBI        Nicoll,  Duncan  &  Rus£ Bemia,  Tennessee  240  WIAD 

WCBJ        J.  C.  Maua Jennings.  Louisiana  244  WIAK 

WCBL       Northern   Radio  Mfg.  Co Houlton,  Me.  280  WIAQ 

WCBM      Charles  Swarz Baltimore,  Md.  229  WIAS 

WCBN      James  P.  Boland Ft.  Benj.  Harrison.  Ind.  266  WIK 

WCBO       The  Radio  Shop,  Inc Memphis.  Tenn.  250  WIL 

WCBQ      First   Baptist   Church Nashville,   Tenn.  236  WIP 

WCBR       C.  H.  Messter Providence,   R.  I.  246  WJAB 

WCBT       Clark  University,  CollegiaU  Dept Worcester.  Mass.  238  WJAD 

WCBU      Arnold  Wireless  Supply  Co Arnold.  Pa.  254  WJAG 

WCBV       Tullahoma  Radio  Club Tullahoma,  Tenn.  252  WJAK 

WCBW     George  P.  Rankin,  Jr.,  and  Maitland  Solomon Macon,  Ga.  226  WJAM 

WCBX      Radio  Shop  of  Newark  (Herman  Lubinsky) Newark.  N.  J.  233  WJAN 

WCBY      The  Forks  Electrical  Shop Buck  Hill  Falls,  Pa.  268  WJAR 

WCBZ       Coppotelli  Broa.  Musio  House Chicago  Heights,  111.  248  WJAS 

WCCO       Washburn-Crosby    Co Twin    Cities.    Minn.  416  WJAZ 

WCEE       Charles  E.   Erbatein.  Villa  Olivia near  Elgin.  III.  278  WJD 

WCK        Stix-Baer- Fuller  D.  G.  Co St.  Louis,  Mo.  275  WJJD 

WCX          Free     Press Detroit.     Mich.  516  WJY 

WDAE       Tampa   Daily  Time* Tampa.  Fla.  365  WJZ 

WDAF       Kansas   City  Star Kansas   City,   Mo.  365  WKA.A 

WDAG      J.   Laurence  Martin Amarillo.  Tex.  263  WKAD 

WDAH      Trinity  Methodist  Church   (South) El  Paso.  Tex-  268  WKAN 

WDAR      Lit    Brothers Philadelphia.     Pa.  394  WKAP 

WDAY      Radio   Eauipment  Corp Fargo,    N.   Dak.  244  WKAQ 

WDBA       Fred     Ray Columbus.     Ga.  236  WKAR 

WDBB       A.  H.  Waite  &  Co.,  Ino Taunton,  Mass.  229  WKAV 

WDBC       Kirk.    Johnson    &    Co ." Lancaster,    Pa.  258  WKBE 

WDBD      Herman     Edwin     Burns Martinsburg,     W.    Va.  268  WKBF 

WDBE       Gilham-Schoen  Elec.  Co Atlantic.  Ga.  278  WKY 

WDBF      Robert  G.  Phillips Youngstown,  Ohio  315  WLAG 

WDBH      C.  T.  SchererCo. Worcester.  Mass.  268  WLAP 

WDBI        Radio  Specialty  Co St.  Petersburg.  Fla.  226  WLAQ 

WDBJ       Richardson    Wayland    Electrio    Corp Roanoke.   Va.  229  WLAX 

WDBL       Wise.  Dept.  of  Markets Stevens  Point.  Wis.  278  WLB 

WDBN      Electrio  Light  &  Power  Co '. Bangor.  Me.  252  WLBL 

WDBO      Rollins     College    Inc Winter    Park,    Fla.  240  WLS 

WDBP       Superior   Stat©   Normal   School Superior.  Wis.  261  WLW 

WDBQ      Morton   Radio  Supply  Co Salem.   N.   J.  234  WMAC 

WDBR      Tremont  Temple  Baptist  Church Boston.  Mass.  256  WMAF 

WDBS      S.  M.  K.  Radio  Corp Dayton.  Ohio  283  WMAH 

WDBT      Taylor's  Book  Store Hattiesburg.  Misa.  236  WMAK 

WDBV      The  Strand  Theatre Fort  Wayne.  Ind.  258  WMAL 

WDBW     The  Radio  Den Columbia.  Tenn.  268  WMAN 

WDBX      OttoBaur New  York.  N.  Y.  233  WMAQ 

WDBY      North    Shore    Congregational    Church Chicago.    111.  258  WMAV 

WDBZ      Boy  Scouts.  City  Hall Kingstown,  N.  Y.  233  WMAY 

WDM         Church   of   the   Covenant Washington.   D.   C.  234  WMAZ 

WDWF      Cranston.    R.    I.  440  WMBF 

WDZ         J.  L.  Bush Tuscola.  HI.  278  WMC 

WEAA       F.  D.  Fallain Flint.  Mich.  250  WMH 

WEAF      American  Telephone  &  Telegraph  Co New  York,  N.  Y.  485  WMU 

WEAH       Wichita  Board  of  Trade Wichita,  Kana.  280  WNAC 

WEAI         Cornell  University Ithaca,  N.  Y.  286  WNAD 

WEAJ        University  of  South  Dakota Vermilion.  S.  Dak.  283  WNAL 

WEAM  Borough  of  North  Plain6eld  (W.  Gibson  Buttfield) .  .  .North  Plainfield.  N.  J  286  WNAP 

WEAN       Shepard    Co Providence.   R.    I.  273  WNAR 

WEAO       Ohio  State  University Columbus,  Ohio  293  WNAT 

WEAP       Mobile   Radio  Co Mobile,  Ala.  263  WNAX 

WEAR       Goodyear   Tire   and   Rubber   Co Cleveland.    Ohio  389  WNYC 

WEAU       Davidson  Bros.  Co Sioux  City.  Iowa  275  WOAC 

WEAY      Iris  Theatre  (Will  Horowitz.  Jr.) Houston.  Texas  360  WOAE 

WEB          Benwood    Co St.   Louis.    Mo.  273  WOAF 

WEBA        Electric  Shop Highland  Park.  N.  J.  233  WOAG 

WEBC       Walter    Cecil    Bridges Superior.    Wis.  242  WOAI 

WEBD       Electrical  Equipment  and  Service  Co Anderson.  Ind.  246  WOAN 

WEBE       Roy  W.    Walker Cambridge.  Ohio  248  WOAO 

WEBH      Edgewater  Beach  Broadcasting  Station Chicago.  111.  370  WOAR 

WEBJ        Third  Avenue  Railway  Co New  York,  N.  Y.  273  WOAT 

WEBM      Radio    Corporation    of   America Portable  226  WOAV 

WEBP       E.   B.   Pedicord New   Orleans.    La.  280  WOAW 

WEBT      The  Dayt on  Coop.  Industrial  High  School ..  - Dayton.  Ohio  270  WOAX 

WEBW       Beloit  College Beloit.  Wise.  283          WOC 

WEBX'     John   E.   Cain.   Jr Nashville.    Tenn.  263          WOCL 

WEB  Y       Hobart      Radio      Co Roalindale.      Mass.  226          WOI 

WEEI         The  Edison  Electric  Illuminating  Co Boston.  Mass.  475          WOO 

WEMC      Barrien  Springs.  Mich 285          WOR 

WEW         St.  Louis  University St.  Louis.  Mo.  280         WORD 

WFAA       Dallas  News  &  Dallas  Journal Dallas,  Texas  472          WOS 

WFAM     Times  Publishing  Co St.  Cloud,  Minn.  273  WPAB 

WFAV  University  of  Nebraska,  Department  of  Electrical  Engineering.  .Lincoln.  Nebr.  275          WPAC 

WFBB       Eureka  College Eureka,  111.  240  WPAJ 

WFBC       First  Baptist  Church Knoxville.  Tenn.  250  WPAK 

WFBD       Gethsemane    Baptist    Church Philadelphia.    Pa.  234          WPAL 

WFBE       John  Van  De  Walle Saeymour.  Ind.  226          WPAU 

WFBG      The  Wm.  F.  Cable  Co Altoona,  Pa.  261  WPAZ 

WFBH      Concourse  Radio  Corporation New  York.  N.  Y.  273          WPG 

WFBJ        St.  John's  University CoUegeville.  Minn.  236          WQAA 

WFBQ       Wynne  Radio  Co Raleigh.  N.  C.  255  WQAC 

WFBR       Fifth  Inf.  Md.  Nat'l  Guard.  5th  Reg.  Armory Baltimore.  Md.  452  WQAE 

WFBT       Gloucester  Co.  Civic  League Pitman,  N.  J.  231  WQAM 

WFBW      Ainsworth-Gates       Radio      Co Cincinnati.  Ohio  309  WQAN 

WFBY       Sisnal  Officer Ft.  Ben  Harrison.  Ind.  258  WQAO 

WFBZ       Knox  College Galesburg,   111.  254  WQAS 

WF1            Strawbridge  and  Clothier Philadelphia.  Pa.  394          WQJ 

WFUV       G.  Pearson  Ward Springfield.  Mo.  252          WRAA 

WFUW     Earl  William  Lewis Moberly.   Mo.  233  WRAF 

WGAL      Lancaster  Electric  Supply  &  Construction  Co Lancaster .  Pa.  248          WRAK 

\VG A  Q     Youree  Hotel Shreveport ,  La.  252         WRAM 

WGAZ      South  Bend  Tribune South  Bend.  Ind.  360         WRAN 

WGBB      Harry  H.  Carman.,  217  Bedell  St. Freeport,  X.  Y.  244  WRAO 

WGBC      First  Biptist  Church Memphis.  Tenn.  266          WRAV 

WGBF       Finke  Furniture  Co Evansville,  Ind.  217  WRAW 

WGBG      Brietenbach's     Radio     Shop Thrifton.     Va.  226  WRAX 

WGBH      Fall    River    Herald    Puo.    Co (Portable)  209          WRBC 

WGBI        Frank      S.       Megargee Scranton.      Pa.  240          WRC 

WGBK      Lawrence    Campbell Johnstown,    Pa.  248  WREO 

WGBM     Theodore    N.    Saaty Providence.    R.  I.  234          WRHF 

WGBN      HubRadioShop La    Salle.  III.  266          WRK 

WGBO      Dr.  Roses   Artan San  Juan,  P.   R.  275          WRL 

WGBP       M.    L.   Price   Music   Co Tampa.  Fla.  250          WRM 

WGBQ      Stout  Institute Menominee.  Wis.  234          WRR 

WGBR      Marshfield     Broadcasting      Assn Marshfield.    Wis.  229          WRW 

WGBS       Gimbel  Brothers New  York.  N.  Y.  315          WSAB 

WCBT      Furman    University Greenville.     S.     C.  236          WSAC 

WGBW     Valley   Theater. Spring  Valley.  111.  212  WSAD 

WGBX      University    of    Maine Orono.  Me.  252          WSAG 

WGB Y      Progress  Sales  Co R.  R.  No.  2  218          WSAI 

WG1            American  R.  &  R.  Co Medford  Hillside.  Mass.  261  WSAJ 

WGN          The    Tribune    Co Chicago.    111.  370          WSAN 

WGR          Federal  T.  and  T.  Co Buffalo.  N.  Y.  319  WSAP 

WGY         General   Elec.   Co Schenectady.   N.   Y.  379  WSAR 

WHA          University    of    Wisconsin t Madison,     Wis.  535  WSAU 

WHAD      Marquette  University Milwaukee.  Wis.  280          WSAV 

WHAG      University  of  Cincinnati Cincinnati.  Ohio  222          WSAY 

WMAH      Hafer  Supply   Co Joplin.    Mo.  283          WSAZ 

WHAM     University  of  Rochester  (Eastman School  of  Musio).. Rochester.  N.Y.  278          WSB 

WMAR      SeasideHou.se Atlantic  City.  N.  J.  275          WSL 

WMAS       Courier-Journal  &  Louisville  Times Louisville,  Ky.  399          WSOE 

WHAV      Wilmington  Electrical  Specialty  Co Wilmington,  Del.  360          WSRF 

WMAZ      Rensselaer  Polytechnic  Institute .Troy.  N.  Y.  385          WSUT 

WMB          Sweeney  School   Co Kansas  City,  Mo.  365  WTAB 

WHBA      C.     C.     Shaffer Oil     City.  Pa.  250  WTAC 

WHBB      Hebel's     Store Stevens     Point.     Wis.  240  WTAF 


Rev.  E.  P.  Graham Canton.  Ohio  254 

Chas.      W.      Howard Behefontaine,   Ohio  222 

Beardsley  Specialty  Company Rock  Island,  Illinois  222 

John  JS.  Skane Harrisburg,   Pennsylvania  231 

Culver  Military  Academy Culver,  Indiana  222 

Chesaning  Electric  Co ." Chesaning,  Mich.  227 

Radiovox     Company Cleveland,     Ohio  273 

George    Schubel New    York,    N.    Y.  360 

Bankers    Life    Co Des    Moines,    la.  526 

Howard  R.  Miller Philadelphia,  Pa.  254 

Journal-Stockman   Co Omaha,  Nebr.  278 

Chronicle   Publishing   Co Marion     Ind.  226 

Home  Electric  Co Burlington.  Iowa  283 

K.    &    L.    Co McKeesport,     Pa.  234 

Continental    Electric    Supply    Co Washington.    D.     C.  360 

Gimbel  Bros Philadelphia,  Pa.  509 

American  Electrio  Co Lincoln.  Neb.  229 

Jackson's  Radio  Engineering  Laboratories Waco.  Texas  352 

Norfolk  Daily  News Norfolk,  Nebr.  23 1 

Clifford  L.  White Greentown,  la.  254 

D.  M.  Perham Cedar  Rapids,  Iowa  268 

Peoria    Star Peoria,    111.  230 

The  Outlet  Co.  (J.  Samuels  «fc  Bro.) ; Providence,  R.  I.  335 

Pittsburgh  Radio  Supply  House Pittsburgh,  Pa.  285 

Chicago   Radio    Laboratory Chicago.   111.  263 

Denison  University Grantvilie,  Ohio  229 

Supreme  Lodge.   Loyal  Order  of  Moose Mooseheart,     111.  303 

Radio  Corp.  of  Ama New  York.  N.  Y.  451 

Radio  Corp.  of  Ama New  York,  N.  Y.  455 

H.  F.Paar Cedar  Rapids. Iowa  273 

Chas.  Looff  (Crescent  Park) East  Providence.  R.I.  240 

United  Battery  Service  Co Montgomery .  Ala.  22  5 

Dutee  W.  Flint Cranston.  R.  I.  234 

Radio  Corp.  of  Porto  Rico San  Juan.  P.  R.  340 

Michigan  Agriculture  College East  Lansing,  Mich.  235 

Laconia  Radio  Club Laconia    N.  H.  254 

K  &  B  Electric  Co Webster,  Massachusetts  231 

Dutee  Wilcox  Flint Cransten,  Rhode  Island  236 

Wky  Radio  shop Okla    City.    Okla.  275 

Cutting  <fc  Washington  Radio  Corp Minneapolis.  Minn.  417 

Wm.  V.  Jordan Louisville.  Ky.  256 

Arthur  E.  Shilling Kalamazoo,  Mich.  233 

Putnam  Electric  Co Greencastle.  Tnd.  231 

University   of   Minnesota MinneapoLs,   Minn.  278 

Wisconsin  State  Dept.  of  Markets Stevenspoint,  Wis.  278 

Sears    Roebuck    &    Co Chicago,    111.  344 

Crosley  Mfg.  Co Cincinnati,  Ohio  422 

J.  Edw.  Page  (Olive  B.  Meredith) Cazenovia ,  N.  Y.  261 

Round  Hills  Radio  Corp Dartmouth ,  Mass.  36Q 


No 


al  Supply  Co Lincoln,  Nebr. 


l  Laboratori 


254 


.Lockport.   N.Y.    273 


Trenton  Hardware  Co Trenton  ,N.  J. 

First  Baptist  Church Columbus.  Ohio  236 

Chicago  Daily  News Chicago,  III.  417 

Alabama   Polytechnic    Institute Auburn,  Ala.  2*0 

Kingshighway  Presbyterian  Church St.  Louis,  Mo.  2  30 

Mercer  University Macon,  Ga.  2S1 

Miami    Beach,    Fla.  384 

Commercial     Appeal Memphis,  Tenn.  503 

Ainsworth-Gates     Radio     Co Cincinnati.     O.  321 

Doubledal-Hill  Elec.  Co Washington.   D.  C.  260 

Shepard  Stores Boston.  Mass.  284 

University  of  Oklahoma Norman,  Okla.  258 

Omaha  Central  High  School Omaha.  Nebr.  255 

Wittenberg  College Springfield.  Ohio  271 

First  Christian  Church Butler,  Mo.  210 

Lennig  Brothers  Co.  (Frederick  Lennig) Philadelphia.  Pa.  2 14 

Dakota  Radio  Apparatus  Co Yankton     S.  Dak.  213 

Dept.  of  Plant  and  Structures New  York  .N.Y.  5?6 

Page  Organ  Co Lima ,  Ohio  2  50 

Midland  College Fremont,  Nebr.  230 

Tyler   Commercial   College Tyler,   Texas  353 

Apollo  Theater  (Belvidere  Amusement  Co.) Belvidere.  111.  274 

Southern  Equipment  Co San  Antonio,  Texas  392 

Vaughn  Conservatory  of  Musio  (James  D.  Vaughn) ....  Lawrenceburg.  Tenn.  230 

Lyradion  Mfg.  Co Mishawaka.  Ind.  3"S9 

Lundskow.  Henry  P Kenosha,  Wis.  225 

Boyd  M.  Hamp- Wilmington.  Del.  360 

Pennsylvania  National  Guard,  2d  Battalion.  112th  Infantry Erie.  Pa.  242 

Woodmen  of  the  World Omaha,  Nebr.  526 

Franklyn  J.  Wolff Trenton,  N.  J.  240 


Pain 


School    of    Chiropractio Davenport,  la.     484 


Hotel  Jamestown,  Inc Jamestown,  N.  Y.  275 

Iowa  State  College Ames    la.  270 

John  Wanamaker Philadelphia. Pa.  509 

L.   Bamberger   and   Co Newark  .  N.  J.  405 

Peoples   Pulpit   Assn Batavia,    HI.  275 

State     Marketing    Bureau Jefferson  City .  Mo.  440 

Pennsylvania  State  College 8tate  College.  Pa.  283 

Donaldson  Radio  Co Okmulgee.  Okla.  369 

Doolittle  Radio  Corp New  Haven.  Conn.  263 

North  Dakota  Agricultural  College Agricultural  College.'N.  D.  233 

Superior  Radio  &■  Telephone  Equipment  Co Columbus."  Ohio  236 

Concordia  College Moorhead,   Minn.  236 

John  R.Koch  (Dr.) Charleston.  W.  Va.  273 

The  Municipality  of  Atlantic  City Atlantic  City,  N.  J.  399 

Horace  A.  Beale,  Jr Parkersburg,  Pa.  270 

E.  B.  Gish Amarillo,  Texas  23  i 

Moore  Radio  News  Station  (Edmund  B.  Moore) Springfield,  Vt.  275 

Electrical     Equipment     Co Miami,     Fla.  283 

Scranton  Times Scranton.  Pa.  280 

Calvary  Baptist  Church New  York.N.  Y.  350 

Prince- Walter  Co Lowell,   Mass.  265 

Calumet  Rainbo  Broadcasting  Co Chicago,  III.  4-47 

The  Rice  Institute Houston,  Tex.  255 

The  Radio  Club  (Inc.) Laporte.Tnd.  224 

Economy    Light    Co Escanaba,    Mich.  256 

Lombard  College Galesburg.  III.  214 

Black  Hawk  Electrical  Co Waterloo.  Iowa  236 

St.  Louis  Radio  Service  Co St.  Louis,  Mo.  263 

Antioch  College Yellow  Springs.  Ohio  242 

Avenue  Radio  Shop  (Horace  D.  Good) Reading.  Pa.  238 

Flaxon's  Garage Gloucester  City.  N.  J.  263 

Imaouel  Lutheran  Church Valparaiso.  Ind.  273 

Radio  Corp.  of  Ama Washington,    D.  C.  468 

Reo  Motor  Car  Co Lansing,  Mich.  286 

Washington    Radio   Hospital  Fund Washington.    D.   C.  256 

Doron  Bros Hamilton  .  Ohio  360 

Union  College Schenectady.    N.  Y.  270 

University  of  Illinois Urbana .  III.  273 

id  Fire  Signal  Department Dallas,    Tex.  261 


Tarrytown  Radio   Res.  Labs. Tarrytow 


N.  Y.     273 
275 


Southeast  Missouri  State  Teachers  College Cape  Girardeau,  Mi 

Clemson  Agricultural  College Clemson  College.  S.  C.  336 

J.  A.  Foster  Co Providence.  R.I.  261 

Loren  Vanderbeck  Davis St.  Petersburg,  Fla.  264 

United  States  Playing  Cards  Co Cincinnati.  Ohio  325 

Grove  City  College Grove  City,  Pa.  258 

Allentown    CaTlI-Publishing    Co Allentown.    Pa.  229 

Seventh  Day  Adventist  Church New  York.  N.  Y.  263 

Doughty  &  Welch  Electrical  Co Fall  River.  Mass.  254 

Camp  Marienfeld Cheaham.  N.  H.  229 

C.  W.  Vick   Radio   Construction  Co Houston,  Tex.  360 

Irving  Austin   (Port  Chester  Chamber  of  Commerce).  .Port  Chester.  N.  Y.  233 

Chas.  Electric  Shop Pomeroy .  Ohio  258 

Atlanta    Journal Atlanta  ,     Ga.  428 

J.  and  M.  Elec.  Co Utica.   N.  Y  273 

School   of   Engineering Milwaukee.     Wis  246 

Hardem  Sales   and  Service - Broadlands.   HI.  233 

State  University  of  Iowa Iowa  City,  Iowa  493 

Fall  River  Daily  Herald  Publishing  Co Fall  River.  Mass.  248 

Penn  Traffic  Co Johnstown.  Pa.  360 

Louis  J.  Gallo - New  Orleans  ,La.  2 12 


RADIO  AGE  for  April,  1925 

WITH 


The  Magazine  of  the  Hour  77 

URERS 


New  Advertising  Manager  for 
Zenith  Radio 
Thomas  E.  Carnahan,  formerly  of  H. 
W.  Kastor  and  The  Arnold  Joerns  Ad- 
vertising    Agen- 
cies,    has     been 
appointed      Ad- 
vertising    Man- 
ageroftheZenith 
Radio    Corpora- 
tion in  Chicago. 
Mr.  Carnahan 
is  to  have  charge 
of    all    advertis- 
ing,   whether    it 
be    direct    mail, 
outdoor,   national  or  local  display.     He 
should  be  well  fitted  for  the  position  in- 
asmuch as  he  has  acted  in  the  capacity 
of  space  buyer,  copy  writer  and  produc- 
tion manager,  while  connected  with  the 
two  advertising  agencies. 


Cardwell  Condensers  Now  a 
Standard 

The  Cardwell  Condenser  needs  no  in- 
troduction to  the  advanced  radio  fan. 
They  have  been  on  the  market  for  a  large 
number  of  years.  Most  amateurs  con- 
sider them  a  standard  of  comparison. 
This  is  quite  an  enviable  reputation  to 
have. 

In  the  present  day  market,  many  con- 
cerns are  marketing  condensers  that  are 
especially  designed  to  eliminate  losses. 
It  was  not  necessary  for  the  Cardwell 
people  to  re-design  their  condenser  for 
this  reason.  Their  condensers  have  al- 
ways been  low-loss.  In  fact,  the  term 
low-loss  was  applied  to  their  condensers 
years  ago  to  distinguish  them  from  con- 
densers of  the  ordinary  type. 

Performance  is  the  only  real  test  of  a 
condenser.  The  Cardwell  condensers  have 
proven  their  superiority  because  of  their 
scientifically  correct  design — small  area 
of  contact  between  insulation  and  stator 
supports,  firm  three-point  frame,  per- 
manent alignment,  accurate  adjustment, 
etc. 

Such  details  permit  of  exceptionally 
fine  distance  records,  smooth  tuning,  free- 
dom from  noises  and  changes  in  capacity 
at  given  settings. 

Pearsall  New  Zenith  Distributors 
The  Zenith  Radio  Corporation  of 
Chicago  announce  the  appointment  of 
Silas  E.  Pearsall  as  their  Eastern  Jobbers. 
For  a  number  of  years  the  name  of 
Silas  E.  Pearsall  has  been  identified 
with  the  Victor  Talking  Machine  Co. 
He  won  an  enviable  reputation  while 
acting  as  Victor  jobbers,  successfully 
serving  over  300  Victor  Dealers.  With 
the  advent  of  the  radio  business,  the 
Pearsall  Company  foresaw  a  more  ex- 
tensive field  of  endeavor  in  this  line. 
They  investigated  every  angle  and  phase 
of   the   radio    industry. 


New  Gollos  Receiver  on  Market 
Head  phones  are  not  required  for  the 
Gollos  Circuit,  all  stations  being  easily 
tuned  in  on  the  loud  speaker.  In  many 
cases  the  loud  speaker  can  be  operated 
on  one  step  of  audio  frequency,  the 
volume  being  too  great  when  plugged  in 
on   second    or   third    step.      The    second 


Maj.  Gollos 

step,  however,  is  desirable  and  needed  for 
long  distance  reception.  The  third  step 
is  mostly  desired  for  Summer  receptions 
at  weak  signals  on  loud  speaker.  If  a 
loud  speaker  is  not  at  hand  and  phones 
are  used,  it  will  be  quickly  noted  that  the 
signals  come  through  the  phones  without 
any  deafening  diaphragm  rattle. 

Major  Anatol  Gollos,  the  inventor  of 
the  circuit,  planned  and  installed  the 
electrical  equipment  in  the  Chicago  & 
Northwestern  R.  R.  Station  at  Chicago, 
and  is  the  inventor  of  the  Gollos  Auto- 
matic Train  Control,  which  was  favor- 
ably reported  to  Congress  by  the  Inter- 
state Commerce  Commission.  Major 
Gollos  entered  the  service  of  the  govern- 
ment during  the  war. 

"Audiohm"  Prevents  Distortion 

The  Electrad  "Audiohm,"  manufac- 
tured by  the  Electrad  Company,  Inc., 
of  428  Broadway,  New  York,  is  showing 
increasing  popularity  among  the  fans 
who  "build  their  own"  as  well  as  manu- 
facturers who  have  been  incorporating 
this  new  unit  into  their  sets. 

The  "Audiohm"  controls  tone,  quality 
and  volume  remarkably  and  is  also  used 
for  resistance  coupled  amplifiers.  It  has 
a  resistance  ranging  from  10,000  to  120,- 
000  ohms  and  works  efficiently  when 
placed  across  the  secondary  of  the  last 
audio  frequency  transformer.  Distor- 
tion is  practically  eliminated  by  intelli- 
gent  use  of  the  "Audiohm." 

The  "Audiohm"  is  but  one  of  the  many 
devices  manufactured  by  the  Electrad 
Company. 


"Telos  Radio" 

Danziger  Jones  Inc.,  25  Waverly 
Place,  New  York,  N.  Y.,  an  old  firm 
of  established  reputation,  is  marketing 
a  receiving  set  kit  under  the  above 
name.  The  kit  is  furnished  in  a  most 
complete  manner  and  the  set  when 
properly  constructed  is  very  efficient. 

The  basic  design  of  the  new  "Telos" 
is  the  same  as  it  has  been  for  three 
years,  with  the  added  improvements  of 
three  stages  of  tuned  R.  F.  and  super- 
imposed (reflex)  resistance  coupled  A. 
F.   as   well. 

The  set  can  be  built  as  a  five,  six,  or 
seven  tube  outfit,  and  will  operate  entire- 
ly on  dry  cells.  It  will  cost  less  to 
operate  than  any  other  set  of  like  power. 
A  crystal  detector  can  be  used  if  desired. 
This  makes  for  increased  economy  of 
operation. 


Alpha  Radio  Supply  Co. 

The  Alpha  Radio  Supply  Company, 
Inc.,  611  Broadway,  New  York  City, 
have  recently  started  production  on  a 
new  product  known  as  Alpha  Insulated 
Bus-Bar  Wire,  (a  spaghetti  covered  bus- 
wire).  An  insulating  compound  is 
applied  to  a  perfect  No.  14  B.  &  S. 
round  tinned  bus-bar  wire.  This  wire 
is  well  tinned,  has  an  even  shiny  surface 
and  covers  a  pure  copper  base. 

This  product  is  energy  conserving 
and  will  undoubtedly  increase  the  sensi- 
tiveness of  a  receiving  set  and  prevent 
short  circuits  where  one  wire  crosses 
another.  The  insulation  may  be  de- 
pended upon  as  permanent  and  will 
retain  its  dielectric  strength  indefinitely. 

Alpha  Insulated  Bus-Bar  Wire  is 
puncture-proof  and  every  length  that 
leaves  is  tested  for  efficiency  in  every 
respect,  including  heat  resisting,  oil, 
water  and  gas  and  acid  proof. 

The  insulating  compound  is  applied 
directly  to  the  wire.  No  cloth,  cotton 
or  any  other  fabric  is  necessary  between 
the  insulation  and  the  wire.  Rolled 
cotton  placed  on  the  wire  is  impractical, 
due  to  the  fact  that  when  stripped,  it 
becomes  unraveled  or  frayed,  making 
an  untidy  job. 

The  wire  is  made  in  uniform,  straight, 
two  (2)  ft.  lengths  and  is  made  in  five 
colors — gold,  red,  black,  blue  and  green. 


A  Portable  Loud  Speaker 
The-  Radiograph  Laboratories,  Chi- 
cago, announce  they  will  soon  begin 
production  of  a  small  loud-speaker  that 
may  be  placed  as  a  part  of  any  portable 
receiving  set,  whether  contained  in  a 
suitcase  or  in  other  form.  This  new 
"Radiograph"  Loud  Speaker  is  of_  the 
reflected  tone  type  and  is  built  for  "dur- 
able wear  in  portable  receivers. 


Additional    Manufacturers'    News    on 
page  79. 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


WTAL 

WTAM 
WTAP 
WTAQ 
WTAR 
WTAS 
*TAT 
WTAU 
WTAW 
WTAX 
WTAY 


CFAC 

CFCA 

CFCF 

CFCH 

CFCJ 

CFCK 

CFCN 

CFCQ 

CFCR 

CFCT 

CFCU 

CFCW 

CFDC 

CFHC 

CFLC 

CFQC 

CFRC 

CFUC 

CFXC 

CFYC 

CHAC 

CHBC 

CHCB 

CHCD 

CHCE 

CHCL 

CHCM 

CHCS 

CHNC 


PWX 

:dw 

2AB 
JOK 
1BY 
ICX 
1EV 
ITW 
JHC 
2L.C 
JKD 
2MN 
2MG 
2JD 


ILO 
51 T 
JWA 
6BM 
JZY 


Toledo  lUdio  &  Electric  Co Toledo,  Ohii 

Willard  Storage  Battery  Co Cleveland,  Ohn 

Cambridge  Radio  A  Electrio  Co Cambridge.  111.    241 

B.  H.  Van  Gordon  4;  Son Oeseo.  Wis.     — 

Reliance   Eectric   Co Norfolk  .  Va. 

Charles  E.   Erbstein Elgin  ,  111. 

Edison  Electric  Illuminating  Co Boston.  Mass,  (portable) 

Rueeg  Battery  <fc  Electric  Co Tecumseh,  Nebr. 

Agricultural  &  Mechanica  1  College  of  Texas College  Station ,  Tex 

William.   Hardware   Co Streator,    111. 

Oak  Leaves  Broadcasting  Station .Oak  Park,  111. 


Calgary  Herald Calgary,  Alberta 

Star  Pub.  &  Prtg.  Co Toronto,  Ontario 

Marconi  Wireless  Teleg.  Co.  of  Canada Montreal,  Quebec 

Abitibi  Power  <fc  Paper  Co Iroquois  Falls,  Ont. 

La  Cie  de  L'Evenement Quebec,  Quebec 

Radio  Supply  Co Edmonton,  Alberta 

W.  W.  Grant  Radio  (Ltd.) Calgary.  Alberta 

Radio  Specialties   (Ltd.) Vancouver.  B.  C. 

Lauren  tide  Air  Service Sudbury,  Ont. 

Victoria     City     Temple Victoria,     British     Col. 

The  Jack   Elliott    Radio   Limited Hamilton,   Ont. 

The  Radio  Shop London,  Ont. 

Sparks  Co Nanaimo,  B.  C. 

Henry   Birks   &    Sons Calgary.   Alta. 

Chas.   Guy   Hunter 551   Adelaide  St.,   London,   Ont. 

The  Electric  Shop  (Ltd.) Saskatoon.  Saskatchewan 

Queens  University Kingston,  Ontario 

University  of   Montreal Montreal,   Quebec 

Westminster  Trust  Co New  Westminster  B.  C. 

Victor     Wentworth     Odium '. Vancouver,     B.     C. 

Radio  Engineers Halifax.  Nova  Scotia 

Albertan  Publishing  Co Calgary.  Alberta 

Marconi  Company Toronto,  Ont. 

Cana.lian  Wireless  &  Elec.  Co Quebec.  Quebec 

Western  Canada  Radio  Sup.  (Ltd.) Victoria,  B.  C. 

Vancouver  Merchants  Exchange Vancouver.  B.  C. 

Riley  &  McCormack Calgary.  Alberta 

The   Hamilton  Spectator Hamilton,   Ont. 

Toronto      Radio      Research Toronto.      Ont. 


Cuban  Telephone  Co Habana 

Pedro  Zayas Habana 

Alberto  S.  de  Bustamante Habana 

Mario  Garcia  Velez Habana 

Frederick  W.  Borton Habana 

Frederick  W.  Borton HaDana 

Westinghouae  Elec.  Co Habana 

Roberto  E.  Ramires Habana 

Ileraldo  de  Cuba Habana 

Luis  Casas Habana 

E.  Sanchez  de  Fuentes Habana 

Fausto  Simon Habana 

Manuel  G.  Salas Habana 

Raul  Peres  Falcon Habana 


252 

WTAZ 

389 

WTG 

242 

WTIC 

220 

WTX 

280 

WWAD 

303 

WWAE 

244 

WW1 

242 

WWJ 

280 

WWL 

231 

WWOA 

283 

.       C+r 

Lai 

430 

L   Otc 

CHXC 

CHYC 

CJBC 

CJCA 

CJGC 

CJCD 

410 

CJCE 

440 

CJCF 

450 

CJCI 

410 

CJCK 

410 

CJCM 

410 

CJCN 

420 

CJSC 

430 

CKAC 

440 

CKCD 

410 

CKCE 

400 

CKCK 

450 

CKCO 

400 

CKCX 

440 

CKLC 

400 

CROC 

400 

CNRA 

410 

CNRC 

410 

CNRE 

410 

CNRM 

400 

CNRO 

440 

CNRR 

415 

CNRS 

420 

CNRT 

350 

CNRW 

11      k 

400 

^tat 

2K 

300 

2HS 

240 

20L 

350 

2WW 

260 

5F.V 

320 

6KW 

220 

6KJ 

230 

6CX 

275 

6DW 

250 

6BY 

350 

6AZ 

270 

8BY 

280 

8FU 

150 

8DW 

Thomas  J.    McGuire Lambertville.   N.    J.  283 

Kansas  State  Agricultural  College Manhattan,  Kans.  273 

Travelers  Insurance  Co Hartford.  Conn.  323 

H.  G.  Saal  Co Chicago,  111.  2<1 

Wright  &  Wright  (Inc.) Philadelphia,  Pa.  380 

The  Alamo  Ball   Room Joli.t.  IU.  242 

Ford   Motor  Co Dearborn.  Mich.  173 

Detroit  News  ( Evening  News  Assn.) Detroit,  Mich.  352 

Loyola    University New    Orleans  .La.  2i0 

Michigan  College   of  Mines Houghton,  Mich.  244 


J.    R.    Booth Ottawa.    Ont. 

Northern   Electric  Co Montreal,  Quebeo 

Jarvis    Baptist    Church Toronto,    Ont. 

Edmonton  Journal Edmonton,  Alberta 

London  Free  Press  Prtg.  Co London,  Ont. 

T.  Eaton  Co Toronto,  Ont. 

Sprott-Shaw  Radio  Co Vancouver,  B.  C. 

The  News  Record Kitchener,  Ont. 

Maritime  Radio  Corp St.  John.  New  Brunswick 

Radio  Corp.  of  Calgary Calgary,   Alta. 

J.  L.  Phillipe. Monti  Job.  Quebeo 

Simons  Agnew  &  Co Toronto.  Ont. 

Evening  Telegram Toronto,  Ont. 

La  Presse  Pub.  Co Montreal,  Quebeo 

Vancouver  Daily  Province Vancouver,  B.  C. 

Canadian  Independ.  Telephone  Co Toronto.  Ont. 

Leader  Pub.   Co Regina,    Saskatchewan 

Ottawa  Radio  Association Ottawa.  Ont. 

P.    Burns  &    Co Calgary.    Alberta 

Wilkinson  Electric  Company Calgary.    Alberta 

Wentworth  Radio  Supply  Co Hamilton,  Ont. 

Canadian   Natl.    Rys. Moncton,  N.  B. 

Canadian  National  Railways Calgary,  Canada 


Canadi 
Canadian    N 
Canadian  Natioi 
Canadian    Natic 
Canadian     Nati. 


Canadi. 
Canadis 


N« 
Nat 


tional       Railways Edmonton,       Alta. 

al   Railways Montreal.    P.    Q. 

.1  Railways Ottawa,  Ont. 

al    Railways Regina,    Sash. 

lal     Railways Saskatoon ,     Sash. 

lal     Railways Toronto.     Ont. 

al    Railways Winnipeg,    Man. 


435 
410 
312 
455 
430 
410 
420 
295 
400 
315 
430 
410 
430 
430 
410 
450 
420 
440 
440 
400 
410 
313 
357 
455 
410 
430 
312 
329 
357 
384 


Alvara  Daza Habana  200 

Julio  Power Habana  1 80 

Oscar  Collado Habana  290 

Amadeo  Saenz Habana  210 

Leopoldo  V.  Figueroa Colon  360 

Frank  H.  Jones Tuinuou  340 

Frank  H.  Jones Tuinuou  275 

Antonio  T.  Figueroa Cienfiegoa  170 

Eduardo  Terry Cienfiegos  22S 

Jose   Ganduxe Cienfiegoe  300 

Valentin    Ullivarri CienBegos  200 

Alberto   Ravelo Stgo.  de  Cuba  250 

Andres   Vinnet Stgo.  do   Cuba  225 

Pedro  C.  Anduz Stgo.  de  Cuba  27» 


European  Broadcasting  Stations 


British  Stations 


London 365  5NO 

Birmingham 475  5SC 

Cardiff 350  2BD 

Bournemouth 385  6SL 

Manchester 375 


Newcastle 400 

Glasgow 420 

Aberdeen 491 

Sheffield  (relay  station) 303 


French  Stations 


Pari 


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We  have  laid  aside  a  limited  number  of 
these  issues.   Select  the  ones  you  want  and 
store  of  radio  knowledge  by  laying  in  an  am 

May,  1922 

—How  to  make  a  simple  Crystal  Set  for  $8. 

September,  1922 

— How  to  make  a  Regenerative  Set  at  a  low  cost. 

October,  1922 

—How  to  make  a  Tube  I 

— How  to  make  an  Audic 

former. 

November.  1922 

— Design  of  a  portable  short-i 

May,  1923 

—How  to  make  a  portable  Roinartt  net  for  summer  uae. 

Juno,  1923 

— How  to  build  the  new  Kaufman  reoeiver. 

— What  about  your  antenna7 

December,  1923 

— Building  the  Haynetj  Receiver. 

- — Combined  Amplifier  and  Loud  Speaker. 

— A  selective  Crystal  Receiver. 

January,  1924 

— Tuning  Out  Interference — Wave   Traps — Eliminators 

—Filters. 

— A  Junior  Super-Heterodyne. 

— Rush-Pull  Amplifier. 

— Rosenbloom  Cirouit. 

March,  1924 

—An  Eight-Tube  Super-Heterodyne. 

— A  Bimple.  low  loss  tuner. 

— A  Tuned  Radio  Frequency  Amplifier. 

— Simple  Reflex  Set. 

RADIO  AGE,  Inc. 


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April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated). 

— A  Ten-Dollar  Receiver. 

— Anti-Body  Capacity  Hookups. 

— Reflexing  the  Three-Circuit  Tuner. 

— Index  and  first  two  installments  of  Radio  As*  Data 
Sheets. 

May,  1924 

— Construction  of  a  Simple  Portable  Set. 

—Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheeta 

June,  1924 

— Important   Factors    in    Constructing   a    Super-Hetero- 
dyne. 

—A  Universal  Amplifier. 

— A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 

— Radio  Age  Data  Sheete. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 

— Operating  Detector  Tube  by  Grid  Bias. 

—A  Three-Tube  Wizard  Circuit. 

— Data  Sheete. 

August,  1924 

— Breaking  Into  Radio  Without  a  Diagram. 

—The  English  4-Element  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheeta. 

September,  1924 

- — How  Careful  Mounting  Will  Improve  Reception. 

— One  Tuning  Control  for  Hair's  Breadth  Selectivity. 

— Four  Pages  of  Real  Blueprints    of  a    New  Baby    Het- 
erodyne and  an  Aperiodic  Variometer  Set. 

— Data  Sheeta. 


Below  are  listed  hookups  to  be  found  in 
The   supply   is   limited,   so   enrich   your 

October,  1924 

— An  Easily  Made  Super-Het. 

—Two  Radio  and  Two  Audio  for  Clear  Tone. 

— A  Simple  Regenerative  Set. 

— The  Ultrndyne  for  Real  DX. 

— Real  Blueprints  of  a   3-Tube  Neutrodyne  and  a  Mid- 
get Reflex  Set. 

November,  1924 

— Blueprints  of  a  Single  Tube  Loop  Set  and  a  capacity 
Feedback  Receiver. 

— A  3-Tube  Low  Loss  Regenerator. 

— Mastering  the  3-Circuit  Tuner. 

December,  1924 

— Blueprints  of  a  New  8-Tube  Super-Heterodyne. 

— How  to  Make  a  Receiver  that  Minimize!  Static. 

—A  Trans- Atlantic  DX  Receiver. 

— How  to  Make  a  Home   M-de   Battery   Charger   enda 
Loud  Speaker  at  a  Small  Cost. 

January,  1925 

— A  Reflexed  Neutrodyne 

—A  Six  Tube  Super-Het 

— An  Efficient  Portable  Set 

— A  Tuned  Plate  Regenerator 

— Making  a  Station- Find  or 

February,  1925 

— A  Sure  Shot  Super-Het 

— A  Three  Circuit  Regenerator 

— A  Real.  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex 

March,  1925 

— A  Permanent  Super-Het 

—A  5-Tube  R.  F.  Receiver 

—How  to  Wind  Low  Loss  Coila 

— A  Short  Wave  Receiver 

—Blueprints  of  a  Two-Tube  Ultra  Audion  and  a   Re- 
generative Reflex 


500  N.  Dearborn  St.,  Chicago 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


79 


Tuning  Dials  Are  Now  Improved  Gain  for  Reflex  Sets 

While   the   engineers   have   constantly  Development    of   reflex    receiving   sets 

striven  to  improve  circuits  and  apparatus  is    already    making    great    progress,    due 

used  in  radio  receivers,  the  manufacturers  largely  to  the  recent  announcement  that 

of  panels  and  dials  of  Bakelite  have  been  the     United    States     Navy     Department 

busy  trying  to  improve  the  appearance  will  license  all  reputable  American  manu- 

and  beauty  of  their  product  to  keep  apace,  facturers  under  the  navy  owned  patents, 

The  mechanical  limitations  of  the  average  which    are    basic    on     reflex    and    radio 


radio  fan  have  also  been  seriously  taken 
into  consideration  by  the  research  and 
design  engineers. 

For  example,  an  improvement  has 
recently  been  made  in  such  a  simple 
piece  of  apparatus  as  a  tuning  dial.  The 
customary  set  screw  which  has  heretofore 


frequency  circuits.  One  of  the  first 
concerns  to  have  its  application  for  a 
license  approved  by  Secretary  Wilbur 
was  the  Ail-American  Radio  Corpora- 
tion. 

The  engineering   staff   of  this  concern 
has   worked   out   a   circuit   which    is   ex- 


been  almost  universally  used  in  attaching  tremely    simple    to    build    and    operate, 

dials  and  knobs  to  the  shafts  of  instru-  and    which    will    give    much    more    than 

ments  has  been  replaced  by  a  much  bet-  ordinary     strength     from     a     minimum 

ter  device.  amount    of    apparatus.      The    reflex   cir- 

A    small    spring    bushing   or   chuck   is  cuit   has  long  been   recognized  as  about 

used.     This  is  slipped  over  the  end  of  the  the    most    economical    to    construct    and 

shaft,  the  dial  then  going  over  the  bushing  operate  and,  in  the  circuit  here  described, 

and  the  knob  is  screwed  up  tightly  on  the  three  tubes  will  do  the  work  of  five  under 

threaded  end  of  the  chuck.     As  the  knob  ordinary  circumstances, 
is  tightened,   the   chuck   grips  the   shaft         The    three    tube    reflex   embodies   two 

from  four  sides  and  the  dial  is  firmly  held  stages  of  radio  frequency,  detector,  and 

in  place  without  the  use  of  tools  of  any  two  stages  of  audio  frequency  amplifica- 

sort.  tion.     The  set  is  highly  selective  and  is 

The   set    screw    method    is   lacking   in  capable  of  receiving  from  long  distances. 

mechanical  fitness.     If  the  shaft  happens  A  crystal  detector  is  used  and  gives  the 

to  be  a  trifle  smaller  than  the  hole  in  the  circuit    true    and    faithful    reproduction, 

ordinary  dial,  the  dial  will  not  run  true  The  range  of  the  set  is  not  limited  by  the 

and  very  likely  will   wabble  and   scrape  crystal  detector,  as  the  signal  is  amplified 

the  panel  at  certain  points.     If  the  shaft  by  two  tubes  before  it  reaches  the  detec- 

is  a  close  fit,  difficulty  is  often  experienced  tor.      In    this    manner    signals    that    are 

in  getting  the  dial  on  or  off  of  the  end  of  too  faint  to  be  heard  with  a  crystal  set 

the  shaft.     Where  instruments  turn  hard,  are   readily   reproduced, 


the  set  screw  often  slips  and  allows  the 
dial  to  turn  without  turning  the  shaft. 


In    contrast    with    many   types   of    re- 
ceiving sets  that  use  three  main   tuning 
dials,    the    reflex    has    but    two,    which 
__    ,     ,.•       __  j   •     t  •  greatly     simplifies     tuning.       The     two 

Bakelite  Demand  IS  Increasing  condenser  dial  settings  follow  each  other 
"The  rapidly  increasing  use  of  bakelite  closely  and  can  be  accurately  "logged" 
in  radio  sets  by  practically  all  of  the  so  that  a  station  can  be  found  again  by 
important  manufacturers  is  of  interest  turning  the  dials  to  the  same  place.  The 
to  the  hundreds  of  thousands  of  radio  circuit  is  non-oscillating  and  therefore 
enthusiasts  throughout  the  country,"  Wl11  .not,  interfere  with  other  receiving 
declared  W.  R.  Yates  of  the  Continental  sets  in  the  neighborhood.  _  _  _ 
Fibre  Company  recently  when  inter-  The  wiring  of  the  receiver  is  simple, 
viewed  on  the  importance  of  good  A11,  !.eads  are  short'  and  us"ally  run  from 
insulation  a    binding    post    on    one    transformer   to 

.,„,  r     ,  ,  .        ,f  the  binding  post  on   an   adjacent  trans- 

'The  amateur  may  find  himself  more    forme      theVeby  eliminating  the  need  of 
or  less  confused,    he  said,    when  he  reads    soldering   connections   in    all   but   a   few 


of  the  electrical  properties  of  any  of  a 
half-dozen  materials  proposed  for  in- 
sulation service  on  his  radio  receiver. 
He  will  find  that  each  of  these  materials 
is  praised  for  some  certain  quality  and 
will  end  by  feeling  that  if  he  could  use 
all  of  them  at  the  same  time  he  would 
have  the  ideal  substance  for  all  purposes. 

"What  he  really  needs  to  know  is 
which  one  material  will  give  him  the 
best  and  most  lasting  service.  Prob- 
ably the  best  way  for  him  to  discover 
this  material  is  to  find  out  what  the 
great  makers  of  really  dependable  radio 
sets    are    using. 

"The  manufacturers  have  been  forced 
to    discard     many    insulating    materials 


places.  In  making  the  connections  on 
the  fixed  condensers,  it  is  well  to  use  a 
small  machine  screw  and  nut,  making 
a  bend  in  the  wire  and  placing  the  loop 
of  wire  under  the  head  of  the  screw  and 
tightening.  It  is  not  advisable  to  solder 
to  the  metal  ends  of  the  condenser  as 
the  heat  of  the  iron  is  liable  to  change 
the  capacity   of  the  condenser. 


A  New  Metalectric  Soldering  Iron 
The  Post  Electric  Co.,  of  125  Harrison 
av.,  Long  Island  City,  N.  Y.,  have  placed 
a  new  Metalectric  Soldering  Iron  on  the 
market  for  radio  use.  Instead  of  a  bulky, 
unwieldy    iron    of    superfluous    size    and 


because  they   do  not   stand  up  and  the     weight,  the  Post  Iron  is  easy  to  handle 
with    these     and  makes  soldering  as  "simple  as  writing 


life  of  radio  sets  equipped 
materials  is  short,"  continued  Mr.  Yates. 
"The  manufacturers  have  adopted  the 
phenolic  condensation  products,  more 
generally  known  under  the  trade  name 
of  bakelite,  either  in  laminated  or 
moulded  form,  and  these  are  being 
used  almost  universally.  Bakelite  has 
none  of  the  changeable  qualities  of  other 
insulating  materials  like  rubber,  and  it 
retains  its  good  properties  indefinitely. 
"The  amateur  can  do  no  better  than 
to  imitate  the  manufacturers.  He  will 
thus  be  profiting  by  their  experience 
and  experiments  and  will  obtain  equip- 
ment for  his  -radio  set  that  will  be 
satisfactory  in  every  way." 


ana  maices  soldering  as    simpl 
with  a  lead  pencil." 

The  iron  is  guaranteed  and  has  these 
features:  there  is  ample  heat  capacity; 
a  quarter-inch  interchangeable  tip  is 
always  ready  for  emergencies;  and  the 
handle  is  always  cool.  The  construction 
of  the  Metalectric  Soldering  Iron  involves 
a  nickeled  brass  handle  and  flange,  fitted 
to  which  is  a  semi-rigid  coil  of  spring 
steel  which  absorbs  the  back  flow  of  heat 
and  prevents  its  passing  to  the  handle. 
The  soldering  tip  is  composed  of  nickeled 
silver,  insuring  minimum  oxidation  and 
infrequent  renewal  of  the  tips. 

The  iron  is  thoroughly  insulated  and 
furnished   with   eight   feet   of  cord   wire. 

•     Tested  and  Approved  by  RADIO  AGE     ¥ 


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Tone  Head  Phones 

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High  grade,  standard  radio  prod- 
that  will  increase  the  efficiency  of  any 
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80 


RADIO  AGE  for  April,  1925 


The  Magazine  of  the  Hour 


Hookups  Like  This  One 
Get  Results! 


Above  is  a  circuit  diagram  of  a  hookup  published  in  the  RADIO  AGE  ANNUAL  for  1925.  and  which  has 
taken  the  radio  fans  by  storm1.  Although  it  is  but  a  three-tube  affair,  it  consistently  "pulled  in"  California 
stations  on  the  loudspeaker  while  located  less  than  a  mile  from  two  powerful  Chicago  broadcasting  stationsl 
Hookups  such  as  these  make  the  ANN  UAL  for  1925  a  necessity  in  your  store  of  radio  knowledge. 

You  11  Find  Them  in  The  Radio  Age  Annual  for  ig2$! 


A     32-PAGE     BLUEPRINT 
SECTION 

is  the  predominating  fea- 
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printed. 


HAVE  YOU  seen  the  new  RADIO  AGE  ANNUAL  for  1925? 
Thousands  of  fans  have  already  bought  their  copies,  and  the 
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tion are  some  of  the  features  that  make  this  1 20-page  book  invaluable 
to  the  technical  fan.  The  expert  will  find  the  latest  in  experimental 
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a  galaxy  of  "how  to  do  it"  articles  written  especially  for  him. 


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RADIO  AGE  ANNUAL 
FOR  1925 

Some  of  the  Features 


$1.00  a 
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How  to  read  and  understand  hookups. 
How  to  understand  radio  phenomena. 
Building  your  first  simple  set. 
How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set. 
How  to  amplify  any  kind  of  set. 
Making  a  reflex  set. 
Building  your  first  Reinartz  set. 
The  renowned  Baby  Heterodyne  No.  1. 
Adding  audio  and  radio  stages  to  the  Baby  Het. 
How  to  make  a  battery  charger. 
How  to  make  a  loud  speaker. 

RADIO    AGE    ANNUAL    BLUEPRINT    SECTION    with    such 
popular  hookups  as  the  aperiodic  variometer,  loop  sets,  feed- 


back receivers,  neutrodynes,  reflex  hookups.  Baby  Het  No.  2t  a 
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How  to  get  rid  of  interference. 

How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super-heterodyne  for  the  super  experimenters. 
'Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

AND  MANY  OTHER  UP-TO-THE-MINUTE  HOOKUPS  AND 
ARTICLES. 


RADIO  AGE  ANNUAL  COUPON 

RADIO  AGE,  INC., 

500  North  Dearborn  St.,  Chicago,  111. 

Gentlemen:       I  want  to  be  one  of  the  first  to  get  the  RADIO  AGE  ANNUAL  FOR  192?.       Enclosed  find  $1.00. 
I  am  not  satisfied  with  the  ANNUAL  I  will  return  it  within  five  days  and  you  will  refund  my  dollar. 


If 


Name 

Address.. 

City 

4-25 


.State.. 


Why  Radio  Receivers  Differ  so  Widely 
in  the  Quality  of  their  Tone 

It's  all  in  the  Overtones 


A  5-tube  Receiver  using  the  new  Pfanstiehl  system  of  tuned  radio  frequency 


/JS  RADIO  becomes  less  of  a  stunt  instrument  for  fans 

/"i  /-I  to  play  with  and  more  of  a  musical  instrument  in 

>_•   J-  the  home,  people  are  demanding,  above  every  other 

value,  TONAL  BEAUTY.  Clear  tone,  of  course,  but  more 

than  that,  lovely  tone — all  of  the  beauty  which  distinguishes 

fine  singing  and  the  best  in  musical  performance. 

It  is  easy  to  get  distance  and  volume  with  proper  amplifica- 
tion. The  difficulty  has  been  to  control  the  tone — to  keep  it 
free,  flexible,  full  and  rich. 

In  the  average  radio  receiver  the  tone  is  sometimes  clear, 
and  sometimes  not.  That  depends  upon  neutralization.  But  it 
is  always  flat,  thin  or  hard.  It  lacks  those  delicate  overtones 
which  give  to  the  tone  itself  its  quality  or  timbre.  It  is  the 
attendant  overtones  or  harmonics  which  make  real  music. 
Without  them  you  have  merely  pitch. 

The  difference  between  a  fine  piano  tone  and  a  pure  piano 
tone  is  in  the  overtones.  Middle  "C,"  for  instance,  is  Middle 
"C"  all  the  time  and  everywhere,  as  far  as  pitch  is  concerned. 
But  there  is  the  widest  difference  in  quality.  One  has  a  rich, 
sweet  resonance.  The  other  is  thin  and  bare. 

The  same  is  true  of  the  human  voice.  Its  charm  is  all  in 
the  overtones.  They  identify  it,  make  it  an  intimately  personal 
thing. 

The  matchless  tone  of  the  Pfanstiehl  lies  in  its  perfect  control  of  the 
overtones — a  simple  thing  and  still  the  most  important  thing  which 
has  as  yet  happened  to  radio. 

Overtones 
perfectly  reproduced 

Of  course,  no  radio  can  receive  a  poor  tone  and  make  it  sound 
beautiful.  It  does  not  create  tones.  It  reproduces  them.  Its  ut- 
most achievement  is  to  reproduce  from  a  distance  the  ///// 
depth  and  individual  beauty  of  fine  music.  That  has  not  been 
possible  hitherto.  Radio  has  not  been  able  to  bring  in  and 
hold  intact  the/#//stream  of  radio  energy  embracing  not  only 


the  fundamental  tone  but  also  ALL  the  minute  overtones 
which  accompany  it  in  transmission  and  should  accompany 
it  in  reception,  if  enjoyable  song  or  music  is  to  result. 

The  radio  stream  gets  out  of  bounds,  as  it  were,  in  the  set 
itself.  It  spills  over  between  circuits  and  feeds  back  instead 
of  forward.  In  entering  the  preceding  circuit  this  feedback  of 
stray  energy  causes  a  disturbance  in  it,  the  two  being  "out  of 
phase,"  as  an  electrician  would  say.  The  true  forward  stream 
of  radio  energy  does  not  mesh  with  the  stray  energy  feeding 
back.  They  conflict.  Squeals  and  noises  result.  To  prevent 
them,  neutralizing  devices  have  been  used.  But  these  do  not 
work  unless  perfectly  adjusted.  And  even  if  they  do  work,  both 
they  and  the  feedback  tend  to  blur  or  spoil  the  delicate  overtones  of 
the  true  signal. 

No  errors  to  neutralize 

In  the  Pfanstiehl  there  are  no  internal  noises  possible.  The  radio  energy 
is  completely  controlled.  There  is  no  feedback.  No  absorbing  or  neu- 
tralizing devices  are  used.  They  are  not  needed.  How  this  control  is 
accomplished  is  a  technical  story  of  great  interest  to  radio  engineers, 
told  elesewhere  in  this  statement.  Briefly,  it  consists  of  a  new  system  of 
reception  designed  ro  hold  in  leash  the  full  forward  stream  of  radio 
energy,  so  that  none  of  it  spills  over  or  escapes  to  cause  feedback.  All 
of  the  overtones  axe  thus  included.  And  you  get  full  tone  quality,  the 
timbre  -which  makes  the  emotional  appeal  in  music  and  gives  to  the  human 
voice  its  supreme  charm. 

Nothing  could  be  simpler.  Nothing  could  be  more  important,  if  radio 
is  to  become  the  enjoyable  instrument  people  are  looking  for.  The  sim- 
plicity of  the  Pfanstiehl  is  unique.  There  are  no  complications.  Nothing 
to  adjust  or  get  out  of  order.  Operation  is  dependable  and  absolutely 
quiet.  In  this  respect  distance  makes  no  difference.  No  lover  of  music 
who  has  once  listened  to  a  Pfanstiehl  will  ever  be  satisfied  with  any 
other  system  of  radio  reception,  its  superiority  is  so  marked. 

Hear  the  new  Pfanstiehl  Overtone  Receiver  at  your  radio  or  music 
dealer's.  If  he  does  not  have  one  we  can  quickly  get  it  to  him. 

PFANSTIEHL  RADIO  COMPANY 

Sales  Offices:  1 1  S.  La  Salle  St.,  Chicago,  111. 
Factories :  Waukegan,  111. 


OVERTONE  RECEIVER 


¥     Tested  and  Approved  by  RADIO   AGE     * 


■■■■<.: 

? 

■■>,< 

■■/■■:.. 

I, 


The  popularity  of  the  Crosley  three-tube  52  at  $30,  has  encouraged 
us  to  offer  this  circuit  in  a  new  attractive  cabinet  with  sloping 
panel — the  Crosley  52  Special  at  $35.  This  cabinet  is  large 
enough  to  hold  all  dry  cell  batteries.  A  beautiful  piece  of  furni- 
ture which  can  take  its  place  in  the  living  rooms  of  the  most  dis- 
criminating. The  sloping  panel  makes  operation  easier  and 
greatly  adds  to  the  appearance  of  the  set.  Of  course,  the  popular 
Crosley  52  will  be  continued.  It  has  given  satisfactory  loud 
speaker  service  in  all  parts  of  the  country.  Continual  coast  to 
coast  reception  and  even  foreign  stations  on  the  loud  speaker 
have  been  reported. 

Prices  West  of  Rockies  add— 10% 


The  Crosley  one-tube  50,  at  only  $14.50,  "The  Little  Giant  of 
Radio,"  has  astounded  owners  with  the  distant  stations  that  it  . 
brings  in,  on  ear  phones  of  course.  All  parts  of  the  United  States 
report  European  stations  weie  heard  during  International  Test 
Week.  It  is  the  radio  with  which  Leonard  Weeks  of  Minot, 
North  Dakota,  kept  in  constant  touch  with  the  MacMillan  ex- 
pedition at  the  North  Pole.  For  true  radio  value,  it  is  excelled 
only  by  the  other  larger  Crosley  Radios.  You  can  purchase 
Crosley  instruments  from  most  any  good  dealer.  All  Crosley 
Radios  are  licensed  under  Armstrong  Regenerative  U.  S.  Patent 
1,113,149.      Prices  quoted  are  without  accessories. 

Write  for  Complete  Catalog 


THE  CROSLEY  RADIO  CORPORATION 


* 


POWEL  CROSLEY,  JR.,  President 
463  Sassafras  St.,  Cincinnati,  Ohio 

Crosley  owns  and  operates  Broadcasting  Station  WLW 


i 
I 

m 

I 

m 

m 

■'■'/■' 
m 


*      Tested  and  Approved  by  RADIO   AGE      * 


Blueprint  Section  Every  Month 


via 


They  Cost  More 

But  They  Do  More 


Super- Zenith  -X"— 
the  ideal  radio  set 
for  the  fine  home 


Zenith— 

the  exclusive  choice 

of  MacMillan  for  his 

North  Polar 

Expedition 


# 


Zenith  Supremacy 
'will  be  Maintained 


This  message  brings  to  radio  en- 
thusiasts the  announcement  of  an 
advance  in  Zenith  prices  on  all 

models.  The  new  prices  are  shown 
in  the  panel  at  the  right. 

Radio  sets — like  motor  cars  and 
pianos — gravitate  to  their  correct 
price  level.  There  is  more  to  a  radio 
receiving  set  than  merely  a  beauti- 
ful cabinet  backed  by  extravagant 
claims.  It  must  meet  exacting  re- 
quirements. The  novelty  has  worn 
off.  The  public  is  becoming  edu- 
cated. It  knows  what  to  expect  and 
can  now  distinguish  merit  in  radio. 

An  imposing  name  and  an  intensive 
advertising  campaign — when  they 
back  a  radio  product  which  does  not 
deliver  equally  impressive  results — 
soon  lose  their  fictitious  values. 

By  that  same  token,  performance 
which  is  literally  outstanding  fixes 


for  the  makers  of  that  product  a 
standard  of  supremacy  which,  in 
duty  to  the  public,  they  are  obligated 
to  maintain. 

Throughout  the  radio  world  the 
name  ZENITH  has  come  to  be  the 
very  symbol  of  results — in  quality  of 
tone,  in  simplicity,  in  selectivity,  in 
volume  without  distortion,  and  in 
long-distance  reception.  The  artistry 
of  design  for  'which  it  stands  is  too 
well  known  for  comment. 

The  fact  that  ZENITH  has  ad- 
vanced its  prices  is  of  more  than 
passing  moment.  For  it  registers  the 
determination  on  the  part  of  the 
builders  of  ZENITH  to  maintain 
the  acknowledged  supremacy  of 
ZENITH  receiving  sets  — both  in 
beauty  and  performance. 

All  present  models  are  guaranteed 
against  price  reduction. 


Dealers  and  Jobbers:    Write  or  voire  for  our  exclusive  territorial  franchise. 

Zenith  Radio  Corporation 


The  complete  Zenith  line  ranges  in 
price  from  $100  to  $475. 

With  either  Zenith  3R  or  Zenith  4R,  sat- 
isfactory reception  over  distances  of 
2,000  to  3,000  miles  is  readily  accom- 
plished, using  any  ordinary  laud 
speaker.  Models  3R  and  4R  licensed  un- 
der Armstrong  U.  S.  Pat.  No.  1,113,149. 
They  are  NON-RADIATING. 

Zenith  4R  -  -  $100 
Zenith  3R  -  -  $175 

The  new  Super-Zenith  is  a  six-tube  set 
with  a  new,  unique,  and  really  different 
patented  circuit,  controlled  exclusively 
by  the  Zenith  Radio  Corporation.  It  is 
NOT  regenerative. 

SUPER-ZENITH   VII—  Six   tubes  — 2 

stages  tuned  frequency  amplification  — 
detector  and  3  stages  audio  frequency 
amplification.  Installed  in  a  beautifully 
finished  cabinet  of  solid  mahogany  — 
44%  inches  long,  162t  inches  wide,  10% 
inches  high.  Compartments  at  either 
end  for  dry  batteries.  Price  (ex-  (h'j  Ar\ 
elusive  of  tubes  and  batteries)  H^T'Vj 

SUPER-ZENITH  VIII—  Same  as  VII  ex- 
cept—console  type.  Price  (ex-  dj-^yrrx 
elusive  of  tubes  and  batteries)  CpZ^OU 

SUPER-ZENITH  IX  —  Console  model 
with  additional  compartments  contain- 
ingbuilt-in  Zenith  loud  speaker  and  gen- 
erous storage  battery  space.  Price  (ex- 
clusive of  tubes  and  bat-  A-jr  r 
teries) tyJDD 

SUPER-ZENITH  X— Contains  built-in, 
patented,  Super-Zenith  Duo-Loud  Speak- 
ers (harmonically  synchronized  twin 
speakers  and  horns),  designed  to  repro- 
duce both  high  and  low  pitch  tones 
otherwise  impossible  with  single-unit 
speakers.  Price  (exclusive  of  <hAHC 
tubes  and  batteries) ^PT*  ■ -^ 


All  Prices  F.  O.  B.  Factory. 


ZENITH  RADIO  CORPORATION 

Dept.  C-5 
332  S.  Michigan  Ave.,  Chicago,  III. 

Gentlemen:  Please  send  me  illustrated  liter- 
ature about  Zenith  radio. 


Address 


332  S.  Michigan  Ave. 


Chicago,  111. 


._] 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  May,  1925 


The  Mai 


of  the  Hour 


PROOF! 


$405  In  One  Month 


I  cleared  up  $405  in 
one  month  recently. 
Not  so  bad — is  it — for 
a  fellow  who  just  com- 
pleted your  course  a 
short  time  ago.  I  sure 
have  been  coining  the 
dough.  I  never  will 
regret  the  money  I 
paid  for  your  course. 
Emmet  Welch, 
Peculiar,   Mo. 


From  $15  to  $80  a  Week 

Before      I      enrolled 
with   you  I  was   mak- 
ing $15   a  week  on  a 
farm.       Now,    I    earn 
£    :.*W'-W$k       from   $2,0S0  to  $4,420 

>L  '  •  *ds£ly     a  *"ear  an(*  the  work 

is  a  hundred  times 
easier  than  before. 
Since  graduating  a 
little  over  a  year  ago, 
I  have  earned  almost 
$4,000  and  I  believe  the  course  will  be 
worth  at  least  $  1 00.000  to  me, 

(Signed)  George  A.  Adams, 
Tamaqua,    Pa. 


Triples  Salary 


I  am  earning  three 
times  as  much  as  be- 
fore enrolling  and  I 
have  clean  interesting 
work  that  takes  me  to 
all  parts  of  the  globe. 
I  tell  you,  boys,  it's 
Radio  for  me. 

Arthur  Herke, 
Vancouver,  B.  C. 


Earns  College  Education 

I  entered  the  mari- 
time    service     of     the 
Radio    Corporation    of 
America     and     served 
several       months       on 
board    ship.         I     not 
only    had    the    advan- 
tages of  visiting  foreign 
countries    at    no    cost 
to  me,  but  I  was  also 
able    to    save    enough 
money  to  pay  for  my  tuition  to  college, 
G.   E.   Rogers, 
Troy,  N.  Y. 


Do  short  hours,  big  money  and  easy 
work  appeal  to  you? 


RIGHT  now  thousands  of  men  are 
"cleaning  up"  in  Radio.  Right  on 
this  page  you  can  read  the  signed  state- 
ments of  men  who  have  made  big  money 
in  this  "wonder- field."  Men,  who,  a  few 
months  ago,  knew  nothing  about  electricity 
or  Radio  now  hold  fine  positions  and  earn 
more  money  in  one  week  than  they  used 
to  get  in  a  month! 

Every  day  thousands  of  Radio  sets 
are  being  sold;  broadcasting  stations  are 
being  established;  Radio  stores  are  spring- 
ing up  everywhere.  People  all  around 
you  are  getting  rich  in  this  splendid- 
paying  profession — Why  Not  You? 

You  can  train  for  this  "big-money" 
field  in  your  own  home — in  a  little  spare 
time.  No  electrical  experience  is  neces- 
sary. Men  and  boys  of  all  ages — 14  to  60, 
have  mastered  this  famous  course  in  a  few 
months.  What  others  have  done,  you  can 
do. 

Radio  has  come  to  stay.  It  is  the  fastest 
growing  industry  in  the  world  today.  But 
remember — the  "cream"  will  go  to  the 
shrewd  fellows  who  get  in  on  the  "ground 
floor."  Employers  are  constantly  writing 
to  the  National  Radio  Institute  asking  for 
Radio  Operators,  Salesmen,  Radio  Engi- 
neers, Radio  Mechanics,  Broadcasters,  etc. 
Many  of  our  students,  even  before  com- 
pleting their  course  have  received  offers  of 
fine  positions  at  twice  their  former  salary. 
In  fact,  most  students  make  so  much 
money  in  their  spare  time  on  Radio  work 
that  this  Course  Becomes  Practically  Free. 

What  Is  the  Secret  of  this 
Amazing  Method? 

The  National  Radio  Institute  Course  is 
acknowledged  by  Radio  executives  to  be  the 


FREE  Instruments 
&r practical  training at  home 


This  is  the  world-famous  Natrom- 
eter — one  of  the  three  instruments 
given  for _  scientific  and  practical 
home  training  in  mastering  the 
code. 


These  parts  with  instruc- 
tions are  given  for  experi- 
ence and  practical  training 
in  making  and  operating 
regenerative  receiving  ap- 
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These  parts  withcom- 
plete  instructions  are 
given  for  practice  in 
building  a  receiving 
set  of  the  more  simple 
kind. 


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best  obtainable  at  any  price.  The  whole 
success  of  the  Institute  is  based  on  its 
advanced  methods.  This  is  the  ab- 
solutely complete  course  now  being 
offered  which  will  qualify  you  for  a  govern- 
ment first-class  commercial  license  and 
really  get  you  one  of  the  bigger  paying 
jobs  in  Radio. 

Free  Instruments 

The  Institute  furnishes  free  of  charge  all 
instruments  necessary  for  practical  in- 
struction at  home' — you  "learn  by  doing." 
That  is  one  reason  why  National  Radio 
Institute  graduates  get  ahead  so  quickly, 
and  obtain  the  Government  License  easily. 

Send  for  "Rich  Rewards 

in  Radio"  and  Special 

Short-Time  Offer 

This  interesting  book  will  tell  you  the 
full  story  about  the  wonderful  opportuni- 
ties in  Radio.  You  will  see  for  yourself 
just  how  much  you  can  expect  to  earn  in 
this  great  profession.  It  will  tell  you  of  the 
adventure  and  big  money  that  awaits  the 
ambitious  man  in  this  fascinating  field. 
Those  who  mail  the  coupon  at  once  will  be 
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save  money!  Send  to- 
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NATIONAL  RADIO 

INSTITUTE 

Dept.  53GB 
Washington,  D.  C 


National  Radio  Institute,  Dept.  53  GB, 
Washington,  D.  C. 

Send  me  the  book,  "Rich  Rewards  in  Radio,"  whicn 
tells  all  about  the  opportunities  in  Radio,  how  spare  time 
study  at  home  will  qualify  me  quickly  as  a  Certified 
Radio-trician  so  I  can  get  one  of  these  splendid  positions. 
and  how  your  free  Employment  Service  helps  me  to 
secure  a  good  position.  Also,  details  of  your  Special 
Short  Time  offer. 

Name .Age. _._. 

Address 

City State._ 


©C1B657753 
RADIO  AGE  for  May,  1925 


The  Maeazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITH  WHICH  IS  COMBINED   RADIO  TOPICS 


Volume  4 


May,  1925 


Number  5 


CONTENTS 

Cover  Design  by  Fred  I.  Good 
Radio  Editorials '. 4 

Where  the  Howls  Come  from 7 

By  Frank  D.  Pearne 
A   '"Quiet"    Regenerator 9 

By  Arthur  B.   McCullah 

How  to  Make  a  Vacuum  Tube  Tester 11 

By  H.  Frank  Hopkins 

A  Power  Supply  Receiver.. 13 

By  Brainard  Foote 

All  Ready  for  a  Radio  House-Cleaning?.... 15 

By    Paul   Green 

x-\n  Improved  Reinartz  Receiver _ 17 

By   Ray   G.    Piety 

A  Unique  Super-Heterodyne   Receiver 19 

By  Joseph   Calcaterra 

The  Physical  Significance  of  Tuning 22 

By  Dr.  Frederick  W.  Grover 
"What  the  Broadcasters  are  Doing":  RADIO  AGE 

Studio-Land    Feature    Section 23 

RADIO  AGE  BLUEPRINT  SECTION..- 31 

A  Six-Tube  Portable  Receiver 

By  John  B.  Rathbun 

RADIO  AGE  Institute  Monthly  Tests 39 

The  World's  Smallest  Studio  on  the  Air 40 

Pickups  and  Hookups  by  Our  Readers.. 41 


Radio  Age  is  published  monthly  by  RADIO  AGE,   Inc. 
Member:      Audit  Bureau  of  Circulations. 


Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500   N.  Dearborn   Street,    Chicago,    111. 
Publication    Office,    Mount    Morris,    111. 


Frederick  A.  Smith,  Editor 
Russell  H.  Hopkins,  Associate  Editor 
Frank  D.  Pearne,  Technical  Editor 
M.  B.  Smith,  Business  Manager 


Advertising  Director 
HARRY  A.  ACKERBURG 


Eastern  Representative 
DAVIDSON    &   HEVEY,    17  West  42nd  St.,  New  York  City 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 

preceding  date  of  issue 

Issued  monthly.    Subscription  price  $2.50  a  year. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris,  Illinois,  under  the 

Act  of  March  3,  1879. 


Copyright,  1925,  bu  RADIO  AGE,  Inc. 


A  Chat  With 
the  Editor 

RADIO  Corporation  of  America, 
it  appears,  is  not  at  all  in  a 
hurry  to  submit  proof  that  this 
magazine  is  not  entitled  to  the  use  of 
the  name  which  we  have  been  using 
for  more  than  three  years.  Radio  Cor- 
poration, with  great  show  of  moral  in- 
dignation, went  into  the  United 
States  Patent  Office  at  Washington 
last  Fall  and  made  formal  protest 
against  the  registration  of  the  title 
"Radio  Age,"  which  name  we  had 
sought  to  have  officially  enrolled  as 
our  trade  mark.  Radio  Corporation 
claimed  that  the  use  of  the  name 
"Radio  Age"  was  causing  damage  to 
"Wireless  Age,"  the  organ  of  the 
Corporation,  owned  and  controlled 
by  the  Corporation. 

Radio  Corporation  was  to  have  sub- 
mitted proof  to  substantiate  its  ob- 
jections to  the  use  of  our  name.  The 
Patent  Office  said  this  proof  must  be 
submitted  on  or  before  March  21. 
Instead  of  offering  proof,  Radio  Cor- 
poration asked  for  a  continuance. 
Our  counsel  consented  once  more. 
The  case  will  not  come  up  until  late 
in  April,  when  there  likely  will  be 
another  request  for  delay. 

Meanwhile  RADIO  AGE  moves  on 
smoothly.  It  broke  all  its  own  records 
for  circulation  and  advertising  in  the 
March,  1925,  issue.  We  continue  to 
receive  many  letters  from  fans  wish- 
ing us  success  in  our  defense  against 
the  $33,000,000  band  of  Broadway 
radio  patriots. 

Radio  Corporation  is  fortunate  in 
obtaining  delays.  The  Corporation 
was  to  have  appeared  before  the 
Federal  Trade  Commission  on  March 
18  to  answer  the  charge  that  it  is 
involved  in  a  trust  conspiracy.  Radio 
Corporation  wanted  delay.  Although 
the  charges  were  filed  a  year  ago, 
Radio  Corporation  obtained  more 
time  to  present  its  defense. 

Changes  have  been  made  recently 
in  the  personnel  of  the  Federal  Trade 
Commission.  We  venture  to  suggest 
the  hope  that  the  Commission  still 
will  be  courageous,  fair,  persistent, 
and  diligent  in  pushing  this  radio 
trust  inquiry.    Why  should  it  not? 

If  there  is  a  radio  monopoly — bust 
it     now\ 

Editor  of  RADIO  AGE 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


Recommend 
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In  an  effort  to  reduce  the  first  cost  of  a 
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*     Tested  ayid  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  May,   1925 


The  Magazine  of  the  Hour 


"EBER  MacDONALD,  writer  of  pub- 
licity for  the  Grebe  radio  people  down 
at  Richmond  Hill,  N.  Y.,  has  written 
a  classic  commentary  on  the  radio  trust.  It  is 
so  good  we  are  printing  it  in  full.  Know  ye  all 
men  that  we  agree  with  every  statement  in  the 
editorial.  RADIO  AGE  has  had  some  direct 
experience  with  the  Radio  Corporation  of  America 
and  the  radio  public  now  knows  pretty  definitely 
what  we  think  of  the  patriots  who  have  just 
been  favored  with  another  delay  in  their  hearing 
before  the  Federal  Trade  Commission  on  the 
charge  of  being  involved  in  a  conspiracy  to 
gobble  up  the  radio  industry. 

Mr.    MacDonald's   editorial    follows: 

RADIO  fans — come  out  of  the  past — it's  haunted. 
At  least  it  looks  that  way,  especially  since  history 
repeats  itself.  You  may  have  noticed  the  Selden 
patent  crowd  passed  into  the  cold  and  unrelenting 
grasp  of  a  receiver  the  other  day.  If  you  have  any 
recollection  of  the  early  days  of  the  automobile  busi- 
ness, you  must  recall  Selden  and  his  patent.  It  was 
a  wonderful  patent.  It  worked  day  and  night.  No 
time  off  for  good  behavior.  No  one  could  make  any 
money  with  it  and  Selden  said  no  one  would  be  allowed 
to  make  any  money  without  it.  And  in  those  olden, 
golden  days,  Selden  was  all-powerful.  He  even  ad- 
mitted it  on  high  days  and  holidays. 

About  the  country  like  a  roaring  lion  went  Selden 
seeking  whom  he  might  devour.  Courage  sprang 
from  his  clenched  fist.  He  shook  his  patent  at  every 
auto-maker  and  collected  much  largess.  They  were 
taxed  to  live.  And  this  tax  W^.s  a  heavy  drain  on  the 
then  infant  motor-car  industry.  But  once  on  a  day 
a  young  manufacturer  in  Detroit,  H.  Ford,  by  name, 
told  the  Selden  gang  where  they  could  go  and  he 
strongly  advised  them  to  take  their  leech-like  patent 
with  them. 

Such  a  patent  octopus  is  considerably  like  an  over- 
inflated  balloon ;  along  comes  some  one  armed  with  the 
spear  of  common  sense  and  the  balloon  is  bust.  'Most 
any  man  with  back-bone  has  a  good  chance  to  deflate 
an  octopus.  An  octopus  is  always  an  evil.  Thrice 
armed  is  he  whose  cause  is  j  ust.  The  octopus  trembles 
at  the  very  mention  of  justice. 

And  what  has  all  this  dissertation  to  do  with  radio? 
Nothing  much  except  that  there  is  another  patent 
octopus  trying  to  suck  the  life-blood  out  of  the  inde- 
pendent radio  manufacturers  who  have  not  bowed  the 
knee  to  Baal.  The  independent  radio  manufacturers 
believe  they  have  the  right  to  live  without  paying 
tribute  to  the  radio  trust.  This  right  to  live  is  denied 
to  the  independent  radio,  manufacturers  by  the  minions 
of  the  fat  and  over-fed  radio  trust.  A  brilliant  array 
of  expensive  legal  talent  do  the  daily  bidding  of  the 
Four   Horsemen   of    Destruction. 

But  the  little  band  of  independents  know  not  fear. 
They  have  forgotten  the  Trust  and  its  threats.  The 
Trust  belongs  to  the  stolid  past.  The  Independents 
look  to  the  plastic  future.    In  the  words  of  the  Apostle 


Paul  they  seems  to  speak  as  one  man:  "This  one 
thing  I  do,  forgetting  those  things  which  are  behind 
and  reaching  forward  unto  those  things  which  are 
before;  I  press  toward  the  mark."  This  valiant  little 
group  of  independents  have  a  fixed  image  in  mind 
from  which  all  this  extraneous  and  non-essential  patent 
hokum  has  been  extracted  or  subtracted. 

Meanwhile,  in  the  ranks  of  the  Four  Horsemen 
there  is  much  gnashing  of  teeth.  This  great  radio 
Goliath  of  Greed  may  have  its  day  of  recknoning 
put  off  again  and  again — as  instanced  by  the  recent 
delay  on  March  18 — but  the  end  is  not  afar  off.  The 
Trust-buster  is  just  around  the  corner.  Some  one 
had  better  summon  a  Daniel,  for  there  surely  is  a 
hand-writing  on  the  wall :  "MENE,  MENE,  TEKEL, 
UPHARSIN."  The  free  translation  seems  to  be 
"Thy  kingdom  is  numbered.  Thou  art  weighed  in 
the  balances  and  found  wanting.  Thy  kingdom  is 
divided  and  given  to  the  Medes  and  Persians." 

Uncle  Trusty,  they  have  your  number  The  bearers 
are  at  the  door. 

THE  use  of  radio  broadcasting  stations  as  advertis- 
ing machines  is  the  greatest  peril  the  new  art  is 
facing  today.  The  eager  listener  who  hopes  to  hear 
good  music  and  who  instead  gets  a  dissertation  on  Jones' 
pills  or  Brown's  sausage  is  not  going  to  remain  a 
devotee  of  the  dials.  In  promoting  advertising  as  a 
means  of  financing  stations,  the  broadcasters  who  have 
succumbed  to  the  commercial  influence  are  building 
up  a  monster  who,  like  Frankenstein,  will  slay  its 
creator. 

Chicago  has  three  advertising  broadcasting  stations 
and  is  about  to  acquire  more.  New  York  has  a  big 
advertising  station  in  WEAF,  and  the  saddest  part  of 
that  story  is  that  the  ballyhoo  was  organized  by  the 
American  Telephone  and  Telegraph  Company.  The 
Pacific  coast  has  its  advertising  problem.  "Radio," 
the  San  Francisco  monthly,  says  in  its  April  issue: 

"Radio  is  too  fine  a  thing,  it  has  too  great  possibili- 
ties in  the  advancement  of  human  welfare,  to  be 
prostituted  to  such  base  ends.  If  this  practice  continues 
to  increase,  and,  if  the  warnings  are  not  heeded,  the 
public  will  realize  that  it  is  being  imposed  upon  and 
turn  to  other  forms  of  entertainment." 

The  writer  was  discussing  the  advertising  peril  with 
a  conspicuous  leader  of  radio  activity  and  thought 
recently,  and  suggested  the  desirability  of  vigorous 
agitation  against  such  misuse  of  the  air.  The  radio 
man  said  there  was  no  question  about  the  danger  of 
advertising  propaganda  to  the  radio  industry  and  the 
radio  art  IF  SUCH  ADVERTISING  WAS  CON- 
TINUED.   But,  he  said,  the  disease  would  cure  itself. 

He  confidently  expressed  the  opinion  that  the  public 
would  solve  this  problem,  as  it  has  solved  other  radio 
problems.  The  public  would  calmly  tune  out  the  ad- 
vertisers until  the  "broadcaster  -  for  -  business  -  only" 
found  that  he  had  no  audience  and  then  he  would  have 
to  quit  for  want  of  contracts.  A  consummation  de- 
voutly to  be  wished,  and  may  it  come  speedily. 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour  5 


Radio  at  its 
Finest 

Now  Witftinlfcur  Reach 


Semi- Finished  —  Factory- Mounted 

YOU  buy  this  set  with  the  All' American  parts  prop' 
erly  mounted  on  the  panel  and  baseboard.  Without 
knowledge  of  blueprints,  circuits  or  names  of  radio  parts, 
you  can  wire  up  an  Ali>Amax  Senior  in' one  delightful  eve' 
ning  and  \noiu  that  it  is  right.  It  was  inevitable  that  sooner 
or  later  this  reliable— and  still  economical— method  of  getting 
a  high'grade  radio  set  should  be  discovered.  All' American 
manufacturing  ingenuity  has  found 
the  solution  and  offers  this  com- 
pletely mounted,  highly  efficient 
three-tube  set  at  no  more  than  you 
would  pay  for  a  kit  of  parts.  Price,  $42 

Ten  cents  will  bring  you  the  new  Radio  Key- 
Book,  and  upon  request  we  will  include,  free, 
a  complete  wiring  blueprint  of  either  ALL- 
AMAX   SENIOR  or  ALL-AMAX   JUNIOR. 

ALL-AMERICAN  RADIO  CORP. 

E.  N.  Rauland,  President 

2680  Coyne  Street,  Chicago 


ALL-AMAXjUNIOR 

The  same  unique  manufacturing 
methods  that  created  ALL-  AMAX 
SENIOR  have  brought  forth  ALL- 
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that  brings  in  the  local  stations 
on  the  loud  speaker,  or  tunes  them 
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baseboard,  and  clear  photo- 
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are  included.    Price    .    .      ^^ 


*    AN 

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All-American 


*     Tested  avd  Approved  by  RADIO   AGE     ¥ 


6  RADIO  AGE  for  May,   1925 


The  Magazine  of  the  Hour 


Mr.  Manufacturer 

Would  you  write  100  letters 

to  100  people 

to  reach  just  two  men? 

Then,  before  you  invest  your  advertising  dollars — THINK! 


An  analysis  shows  that  publications  of  general  circulation, 
newspapers  and  magazines,  devote  less  than  2%  of  their 
reading  columns  to  Radio — proving  that  in  the  opinion  of 
their  own  Editors  less  than  2%  of  their  readers  are  inter- 
ested in  Radio.  In  fact,  many  general  publications  carry  no 
Radio  editorial  matter.  Therefore — 98%  of  your  investment 
is  lost! 


This  Association 
is  comprised  of 
the  leading  Ra- 
dio Magazines. 


On  the  contrary,  the  Radio  magazine  offers  100%  Radio 
editorial — attracts  100%  potential  buyers. 

Spend  your  advertising  appropriation  in  Radio  Magazines. 
Be  sure  of  the  greatest  possible  return  on  your  advertising 
dollar. 

Radio  Magazine  Publishers'  Association,  Inc. 

RADIO  AGE  is  a  member  of  the  Radio  Magazine  Publishers  Association,  Inc. 


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RADIO  AGE  for  May,  1925                                                                   The  Magazine  of  the  Hour  7 

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1 


36q  Magazine  of  the  Hour 


§  M.  B.  Smith 


Livi.  d.  o  miin 
Business  Manager 
E[====]G][====][3[====]EI====iHt=J 


A   Monthly     Publication 

Devoted  to  Practical 

Radio 


Frederick  A.  Smith  g 

Editor 


3BI =1131 =3BI  IBI  ifii= inr==imr  iinr 


-J 


Self-Oscillations  in  R.F.  Circuits — 

Where  The  HOWLS  Come  from 


IT  IS  a  well  known  fact  that  in  order 
to  get  good  long  distance  reception, 
radio  frequency  amplification  must 
be  used.  This  type  of  amplification 
strengthens  the  incoming  signal,  amplify- 
ing it  to.  such  a  value  that  it  becomes 
strong  enough  to  make  enough  impression 
on  the  detector  to  make  audible  those 
signals  which  otherwise  could  not  be 
heard  with  the  ordinary  receiving  sets. 
No  jacks  are  included  in  the  different 
stages  of  radio  amplification  for  the 
reason  that  they  pass  through  all  of 
these  stages  at  a  frequency  which  is 
much  too  high  to  be  heard  by  the  human 
ear.  They  are  not  made  audible  until 
they  pass  through  the  detector,  where 
the}'  are  brought  down  to  audible  fre- 
quency. Therefore,  jacks  are  of  no 
consequence  at  any  point  preceding 
the  detector.  After  reaching  this  point, 
however,  the  signals  may  be  passed 
through  various  stages  of  audio  fre- 
quency amplification  for  the  purpose  of 
increasing  the  volume  of  the  rectified 
signal,  and  jacks  may  be  inserted  between 
any  of  these  stages,  making  it  possible 
to  vary  the  volume  as  desired.  Most 
all  long  distance  receivers  operate  on 
the  basis  of  both  radio  and  audio  fre- 
quency amplification,  and  no  matter 
what  type  of  radio  frequency  amplifica- 
tion is  used,  there  will  always  be  a  great 
tendency  towards  self  oscillations  in 
these   circuits. 

Cause  of  Howls  and  Squeals 

WHEN  self  oscillation  occurs,  howls 
and  squeals  of  all  kinds  are  pro- 
duced in  the  phones  and  if  these  oscilla- 
tions cannot  be  controlled,  the  benefits 
derived  from  radio  frequency  amplifica- 
tion are  of  no  value  whatever,  and  the 
set  might  better  be  used  without  it. 
Fortunately,  however,  there  are  several 
ways  of  eliminating  the  self  oscillations, 
and  if  this  is  properly  done,  the  receiver 
may  be  made  extremely  sensitive  and 
practically  noiseless  so  far  as  these 
oscillations  are  concerned.  In  order 
that  one  may  fully  understand  just 
what  causes  this  trouble,  it  will  be 
necessary  to  explain  briefly  the  principle 
of  regeneration.  The  well  known 
regenerative   set    makes   use    of   what   is 


By  FRANK  D.  PEARNE 

Control   of  Feedback 
is   Vital  for   Clarity 


known  as  a  feedback,  in  which  part  of 
the  amplified  energy  is  fed  back  from 
the  plate  circuit  to  the  grid  of  the  tube. 
In  this  case,  either  a  tuned  plate  circuit 
or  an  inductive  coupling  of  the  plate 
and  grid  circuit  is  used.  Here  we  have  a 
signal  impressed  upon  the  grid  and 
amplified  by  the  relay  action  of  the  tube 
in  the  plate  circuit.  When  a  change 
takes  place  in  this  plate  circuit,  part  of 
the  energy  is  re-impressed  upon  the  grid 
circuit  by  induction,  which  again  affects 
the  grid,  making  a  still  greater  change 
in  the  current  flowing  in  the  plate  circuit. 
This  change  or  increase  reacts  upon  the 
grid  again,  making  still  more  changes 
in  the  plate  circuit,  which  effect  keeps 
building   up   the   charge   upon    the    grid 


Fig.  1.  Here  current  is  induced  in  the 
secondary  by  a  primary  circuit.  This 
secondary  current  acts  upon  the  grid,  which 
varies  the  current  in  the  plate  circuit. 
This  varying  current  passes  through  the 
tickler  coil  which  again  causes  an  induced 
current  in  secondary,  thereby  affecting  the 
grid  once  more,  making  a  greater  change  in 
the  plate  circuit. 


until  it  reaches  a  point  where  it  becomes 
stabilized  and  no  further  increase  takes 
place.  Aside  from  building  up  the  signal 
on  the  grid,  it  has  the  effect  of  prolonging 
the  signal  to  a  certain  extent,  the  result 
being  a  considerable  amplification  of 
the  signal  by  this  regenerative  method. 
This  is  known  as  a  feedback,  and 
because  it  may  be  controlled,  it  becomes 
a  useful  and  valuable  adjunct  to  the 
receiver.  Thus  we  have  a  case  where 
controllable  oscillation  is  a  benefit, 
but  those  self  oscillations  which  are  set 
up  in  many  sources  of  feedback  which 
are  not  under  control  are  the  cause  of 
the  many  howls  and  squeals  so  often 
encountered  in  radio  frequency  amplifi- 
cation. Where  -several  stages  of  radio 
frequency  amplification  are  used,  some 
of  the  energy  of  the  plate  circuit  may 
be  fed  back  to  the  grid  circuit  to  the 
same  tube,  or  to  preceding  tubes  by 
induction  or  capacity  in  the  circuits 
themselves. 

Coupling  Causes  Trouble 
TfEEDBACKS  of  this  kind  are  un- 
■*-  desirable,  and  unless  some  method 
of  controlling  them  is  used,  self  oscilla- 
tion of  the  tubes  will  cause  an  aggra- 
vating howl  in  the  phones  or  loud 
speaker.  Now  this  action  is  caused  by 
an  unintended  coupling  somewhere  be- 
tween the  grid  and  plate  circuits  of 
the  tubes.  Perhaps  in  the  wiring  of  the 
set  the  wire  connected  to  the  plate  of 
one  tube  may  be  too  close  to  the  wire 
connected  to  the  grid  of  that,  or  some 
other  tube,  or  perhaps  these  two  wires 
may  parallel  each  other  for  some  dis- 
tance, in  which  case  one  will  be  affected 
by  the  other  and  self  oscillations  will 
be  set  up. 

This,  however,  will  not  always  occur, 
for  the  reason  that  if  the  feedback 
occurs  in  one  direction,  it  may  tend 
to  oppose  or  neutralize  the  grid  effect, 
having  a  tendency  to  dampen  out  the 
grid  effect  instead  of  building  it  up. 
Where  many  stages  of  radio  frequency 
amplification  are  used,  coupling  between 
the  plate  and  grid  circuits  may  occur 
in  many  ways.  There  will  always  be  a 
capacity  coupling  between  the  plate 
and  grid  of  any  tube,  because  these  two 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


Fig.  2.  Controlling  the  feedback  from 
3-plate  condenser. 

elements  act  just  as  though  they  were 
the  plates  of  a  condenser.  This  capacity 
coupling  is  always  present  and  cannot 
be  avoided,  and  the  only  way  to  over- 
come it  is  by  neutralizing  its  effect  in  a 
manner  similar  to  that  of  the  neutrodyne 
circuit  in  which  neutralizing  condensers 
are   used. 

The  coupling  may  be  caused  by 
magnetic  action  between  transformers 
which  are  too  close  together,  and  again 
it  may  be  caused  by  resistance  coupling 
where  the  internal  resistance  of  the 
plate  batteries  is  high.  Now  the  energy 
which  is  fed  back  in  any  of  these  cases 
may  be  either  positive  or  negative,  and 
if  it  happens  to  be  positive  in  its  direc- 
tion, or  if  a  positive  feedback  is  strong 
enough  to  overcome  any  negative  feed- 
back which  may  be  taking  place,  con- 
tinuous oscillations  will  be  set  up  and 
howling  will  usually  result. 

One  method  devised  to  overcome  a 
positive  coupling  between  two  circuits 
is  to  provide  a  separate  source  of  negative 
feedback  to  overcome  or  neutralize  the 
effect  of  any  positive  feedback  which 
may  be  taking  place  between  two  cir- 
cuits. 

In  this  method  a  small,  three-plate 
variable  condenser  is  so  arranged  that 
one  movable  plate  may  be  moved  in 
front  of  one  or  the  other  of  the  stationary 
plates  which  are  insulated  from  each 
other,  or  it  may  be  moved  partly  in 
front  of  one  and  partly  in  front  of  the 
other.  The  movable  plate  is  connected 
.to  the  grid  of  the  first  amplifying  tube 
and  the  stationary  plates  are  connected 
to  the  plates  of  the  second  and  third 
tubes,  respectively.  This  arrangement 
is  used  in  resistance  coupled  amplifiers, 
as  in  this  type,  and  each  succeeding 
stage  is  reversed  in  phase.  By  changing 
the  position  of  the  movable  plate  of  the 
condenser,  one  point  of  adjustment  may 
be  found  where  the  feedback  effect 
will  be  absolutely  neutralized.  Other 
positions  of  the  movable  plate  may  be 
found  where  the  feedback  may  be  either 
made  negative  or  positive  as  desired, 
which  makes  it  possible  to  control  the 
feedback  at  will.  In  the  same  way, 
this    method    may   be   applied   to   trans- 


one  stage  to  another  by  means  of  a  special 

former  amplification,  providing  the  secon- 
dary connections  of  the  transformers 
are  reversed  in  relation  to  the  primary 
connections  and  a  small  variable  con- 
denser connected  between  the  plate 
circuits  of  two  tubes. 

The    Potentiometer    Method 

ANOTHER  arrangement,  and  the 
■**-  one  which  seems  to  be  most  popular 
among  the  manufacturers  of  radio  fre- 
quency sets,  is  the  potentiometer  method. 
In  most  cases  the  grid  return  circuits 
of  all  the  tubes  are  connected  to  the 
negative  side  of  the  filament  battery. 
This  tends  to  prevent  oscillations  taking 
place  in  the  tubes,  but  is  not  adjustable. 
By  connecting  a  high  resistance  poten- 
tiometer across  the  terminals  of  the 
filament  battery  and  connecting  the 
grid  return  circuits  to  the  movable 
arm  of  the  potentiometer,  the  grid 
bias  may  be  varied  from  a  negative  to  a 
positive  value,  making  it  possible  to 
obtain  any  adjustment  between  the 
extreme  negative  and  positive  which 
may  be  desired.  By  this  arrangement, 
the  grids  may  be  made  either  negative 
or  positive  with  respect  to  the  negative 


end  of  the  tube  filaments.  If  it  is  found 
that  the  tubes  oscillate  when  the  poten- 
tiometer is  set  at  the  negative  side,  the 
oscillations  may  be  dampened  by  moving 
the   arm    towards   the   positive   end. 

Making  the  grids  of  the  tubes  positive 
with  respect  to  the  filaments  will  natur- 
ally reduce  the  impedances  of  the  grid 
filament  ciixuits,  and  if  this  is  carried 
too  far,  the  grid  filament  circuit  begins 
to  be  conductive,  and  some  of  the  plate 
current  will  be  wasted;  but  if  the  grid 
circuit  is  carefully  balanced  against  the 
feed-back,  then  the  self  oscillations  of 
the  tubes  may  be  easily  controlled.  The 
one  bad  feature  of  the  potentiometer 
method  is  the  fact  that  controlling  the 
oscillations  in  this  manner  is  absolute, 
but  it  increases  the  resistance  of  the 
circuits  and  naturally  the  amplification 
is  reduced.  It  will  be  noted  for  example, 
in  the  use  of  a  superheterodyne  circuit, 
that  at  certain  adjustments  of  the 
potentiometer  the  set  will  oscillate  in  a 
disagreeable  manner,  but  the  volume 
of  the  signal  is  wonderful.  However, 
in  order  to  clear  up  the  reception  and 
make  it  quiet,  the  position  of  the  arm 
on  the  potentiometer  must  be  changed, 
and  as  the  oscillations  begin  to  dis- 
appear, the  volume  drops  off  to  a  con- 
siderable extent  due  to  the  increased 
resistance.  If  some  method  could  be 
devised  by  which  the  oscillations  could 
be  damped  out  and  the  volume  still 
retained,  then  great  amplification  might 
be  had,  with  the  use  of  less  tubes  than 
are  now  necessary.  More  stages  of 
radio  frequency  amplification  are  re- 
quired, of  course,  to  make  up  for  the 
loss  occasioned  by  getting  rid  of  the  self 
oscillations  in  the  tubes.  There  is  a 
limit  to  the  number  of  tubes  which  may 
be  used,  for  the  reason  that  tube  noises 
are  always  present,  and  with  each 
successive  stage  of  amplification  these 
noises  are  amplified  as  well  as  the  signal. 

Audio    Frequency    Amplification 

AUDIO     frequency     amplification,     as 
-  before    mentioned,    is    used    to    in- 
crease  the   volume   of   the   signals   after 
they  have   passed  through  the  detector, 
(Turn  to  page  67) 


t 


Vi^ 


F.F.  TRAN-         fl.F.  TRAN- 


POTV 


#|lhMl|l|l|r 


Fig.  3. 
The  potentiometer  method  of  controlling  the  feedback  is  shown  in  the  diagram  above. 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


Consider  your  Neighbors  with  This 

"QUIET"  REGENERATOR 


BY  ARTHUR  B.  McCULLAH 


A  front  view  of  Mr.  McCullah's  much-discussed  radiation-minimizing  receiver.     After  a  series  of  tests, 
Mr.  McCullah  believes  he  has  nearly  approached  the  ideal  regenerative  set  with  this  four- tube  hookup. 


THE  purpose  of  this  article  is  not  to 
introduce  a  new  circuit  into  the 
radio  folds  for  no  good  reason,  but 
to  introduce  an  old  circuit  with  some  of 
its  disadvantages  overcome. 

The  regenerative  set  can  truly  be 
called  the  "Old  Reliable."  However, 
conditions  have  grown  up  around  it  that 
have  made  it  a  burden  to  the  community 
at  large.  Our  last  trans-atlantic  test 
proved  that  the  radiating  receivers  were 
doomed.  Not  only  is  the  regenerative 
set  a  menace  to  society,  but  the  many 
varieties  of  radio  frequency  amplifiers 
that  go  into  the  state  of  oscillation  cause 
more  trouble  than  a  great  many  regen- 
erative sets. 

Some  have  prophesied  that  in  a  short 
space  of  time  the  owners  of  regenerative 
sets  will  learn  how  to  manipulate  them 
in  such  a  manner  as  not  to  cause  any 
undue  hardship  to  their  neighbors.  Time 
has  not  borne  out  this  prophecy,  and 
some  method  must  be  presented  to  the 
fans  so  they  can  build  sets  that  will  not 
radiate  and  at  the  same  time  be  elec- 
trically efficient,  as  well  as  easy  to  tune. 
The  users  of  most  regenerative  sets  know 
that  by  making  their  sets  oscillate  they 
will  cause  interference,  but  they  con- 
tinue to  use  such  a  practice  because  it  is 
easy  to  find  stations  by  the  beat  note 
that  is  produced  in  their  sets,  as  well  as 
in  every  other  set  in  the  neighborhood 

Some  Criticism  Undeserved 

AS  SAID,  before,  the  regenerative  set 
-'*-  comes  in  for  a  lot  of  criticism  that  it 
is  not  entitled  to.  The  super-heterodyne 
causes  a  great  amount  of  trouble  that 
the  much  abused  regenerative  set  is 
accused  of.  The  radio  frequency  am- 
plifiers in  many  sets  radiate  more  energy 
than   regenerative   detectors,    because   of 


A  Step  Toward  a 
Non-Radiating  Set 

the  high  plate  voltage  as  compared  to 
the  plate  voltage  of  a  detector  tube. 
This,  of  course,  makes  for  a  more  power- 
ful oscillator.  A  general  rule  may  be 
stated  that  any  set  that  goes  into  the 
state  of  oscillation  will  radiate  energy 
unless  some  method  is  used  to  prevent 
the  energy  from  leaving  the  set;  i.  e.,  in 
the  super-heterodyne  receiver  the  second 
harmonic  system  of  wave-changing  or 
the  Pressley  system  of  preventing  radia- 
tion to  a  negligible  quantity. 

Circuit  Analysis 

In  the  set  to  be  described,  the  antenna 
coil  has  (53)  turns  of  Number  twenty- 
four  double-covered  green  silk  wire. 
There  is  a  tap  taken  out  in  the  exact 
electrical  center  which  is  at  the  (26}^) 
turn.  This  is  the  antenna  tap.  The  pur- 
pose of  such  close  coupling  is  to  prevent 
t-he  first  radio  frequency  amplifier  from 
oscillating.  There  is  a  second  method 
that  is  not  always  needed,  but  it  is  put 
in  for  the  few  that  might  find  it 'necessary. 
i  It  will  be  noticed  that  there  is  a  .0005 
variable  condenser  tuning  the  antenna 
coil  and  a  .00035  condenser  tuning  the 
detector  circuit.  The  reason  for  this  is 
that  in  designing  a  set,  practically  every 
builder  will  have  an  antenna  of  a  differ- 
ent capacity,  which  would  change  the 
wavelength  of  the  secondary  of  the  first 
radio  frequency  transformer  to  a  great  ex- 
tent if  the  tuning  condenser  were  a  .00035 
condenser;  hence  the  .0005  variable. 

The    second    radio    frequency    trans- 
former consists  of  two  coils,  a  (24)  turn 


primary  ana  a  secondary  of  (95)  turns 
and  the  same  size  wire  with  which  the 
antenna  coil  is  wound.  There  is  also  a 
tap  taken  out  at  the  center  of  this  wind- 
ing. Regeneration  is  obtained  with  a 
small  variable  condenser.  It  issome times 
known  as  the  Rice  Circuit.  The  primary 
coil  is  wound  on  a  smaller  bakelite  tubing 
so  it  will  make  a  snug  fit  when  it  has  a 
winding  on  it.  In  the  circuit  diagram  it 
will  be  noticed  that  there  is  a  small  fixed 
condenser  in  series  with  the  regenerative 
condenser.  This  is  because  of  the  fact 
that  the  so-called  regenerative  condenser 
has  too  high  a  zero  capacity  to  prevent 
the  detector  tube  from  oscillating  at  the 
lower  end  of  the  scale. 

The  Choke  Coil 

\  S  THIS  circuit  is  what  is  called  a 
-^*-  parallel  plate  supply,  some  method 
must  be  used  to  keep  the  radio  frequency 
energy  out  of  the  plate  supply.  This  can 
easily  be  done  by  inserting  a  small  honey- 
comb coil  in  series  with  the  plate  lead 
of  the  detector.  A  coil  of  one  hundred 
turns  or  more  will  do  the  trick.  It  might 
be  added  that  this  choke  may  be  made 
by  winding  one  hundred  turns  of  the 
same  size  wire  with  which  the  other  coils 
are  wound,  or  if  some  smaller  wire  is 
handy,  use  it  because  it  will  make  a  more 
compact  coil.  The  form  for  winding  such 
a  coil  can  be  had  from  an  old  spool. 

The  usual  precautions  should  be  taken 
in  selecting  the  audio  transformers. 
We  need  not  go  into  the  details  about 
them,  as  they  have  been  discussed  at 
length  in  these  pages  before.  If  the 
builder  wants  to  go  to  considerable  work, 
he  may  use  filament  control  jacks  and 
put  a  jack  in  the  plate  circuit  of  each 
tube  with  the  exception  of  the  radio 
frequency  amplifier. 


10 


RADIO  AGE  for  Mav,  1925 


The  Magazine  of  the  Hour 


mill!lll!(l!lllllllllllllllllllllllllll!lll>lllll!llllllllllllllllll!i 

Panel  view  of  the  "Quiet  Regenerator."  The 

condenser  tunes  the  antenna  coil  while  a  .00035  condenser  tunes  the  detector  circuit 


lllll!lllllll!lllll!l!>!ll!llllllllllll!!ll!l!ll!l!lllllllllllllli;illil!llllllllll 
two  major  controls;  a  .0005  variable 


The  much  important  "C"  battery  is 
left  out  of  many  sets.  This  is  not  the 
case  here,  however,  for  it  is  particularly 
advantageous  when  using  199  tubes  as 
we  do  in  this  set. 

Only  one  rheostat  is  used,  as  199  tubes 
work  best  at  three  volts.  It  does  not  take 
four  rheostats  to  adjust  the  tubes  to 
three  volts,  as  the  tubes  have  the  same 
characteristic. 

List  of  Materials 

1   7  x  14  inch  panel. 

1    7   x   13   inch   panel. 

1   .0005  variable  condenser. 

1  .00035  variable  condenser. 

2  Low  ratio  audio  frequency  trans- 
formers. 

4   199  tube  sockets. 

1   Grid  leak  and  condenser. 

1    Rheostat. 

1   4  spring  jack. 

1    2  spring  jack. 

1   On-off  switch. 

1   Chelton    variable    condenser. 

1  .0001  fixed  condenser. 

2  Bakelite  tubing  3Vg  inch  long,  2 
inch   in   diameter. 

2   Bakelite  tubing  1  inch  long,  1  ?4  inch 
in  diameter. 
2   Dials. 
7   Binding  posts. 


1    X  lb.  No.  24  D.  C.  G.  S. 
1   Neutralizing  condenser. 
Construction 

IT  IS  an  old  Chinese  proverb  that-  "One 
Picture  is  Worth  10,000  Words." 
The  picture  will  tell  in  the  best  way  how 
to  lay  out  the  set. 

The  antenna  coil  should  be  wound  on 
the  center  of  the  bakelite.  The  most 
accurate  way  to  do  this  is  to  drill  a  small 
hole  in  the  tube,  .equidistant  from  both 
ends  of  the  tube  and  wind  on  two  coils, 
using  this  as  the  starting  point  for  both 
windings;  that  is,  26 H  turns  on  both 
sides  of  the  center.  If  the  same  type  of 
condenser  is  used,  the  coil  will  be  mounted 
on  the  back  of  the  condenser.  This  first 
coil  should  be  at  right  angles  to  the 
baseboard. 

The  second  radio  frequency  trans- 
former is  mounted  on  the  back  of  the 
condenser  in  the  same  manner  as  the 
first,  except  that  it  is  parallel  to  the 
baseboard.  In  other  words,  it  is  at  right 
angles  to  the  other  coil.  The  primary  coil 
is  wound  on  the  small  coil  that  is  one  inch 
long,  and  it  has  twenty  turns  of  wire  on 
it.  The  secondary  coil,  as  said  before, 
has  a  tap  and  may  be  wound  the  same  as 
the  primary  coil,  only  it  has  53  turns,  or 
26}'2  each  side  of  the  center  tap. 


While  the  choke  coil  is  very  easy  to 
build,  to  make  the  entire  job  one  of 
simple  assembly,  it  would  be  easy  to 
purchase  one  100-turns  honey-comb  coil. 
For  those  who  want  to  build  their  own 
choke  coil,  a  very  nice  job  can  be  made 
of  an  ordinary  thread  spool.  Wind  on 
one-hundred  turns  of  No.  24  wire  in 
most  any  fashion.  The  ends  of  the  wire 
can  be  brought  out  to  two  screws  at  one 
end  of  the  spool. 

No  trouble  should  be  experienced  in 
constructing  this  set,  as  there  are  no 
"trick"  parts,  nor  are  there  any  moving 
coils  that  would  cause  the  builder  with  a 
limited  number  of  tools  any  difficulty. 

Oscillation  On  First  Tube 

SOME  trouble  has  ,  been  experienced 
with  this  circuit  on  some  antennas, 
due  to  the  first  tube  oscillating.  The 
first  tube  on  some  occasions  broke  into 
oscillation  in  sympathy  with  the  detector 
tube  when  it  oscillates  or  is  about  to 
oscillate. 

The  only  remedy  for  such  a  trouble  is 
to  neutralize  the  radio  frequency  tube. 
Neutralization  is  very  easy  in  this  cir- 
cuit, as  there  is  only  one  tube  to  neu- 
tralize. The  first  thing  to  do  is  to  discon- 
nect the  antenna  from  the  set.  Set  the 
first  dial  at  about  thirty  on  the  dial,  and 
then  turn  the  second  dial  until  the  click 
is  heard  in  the  headphones,  which  indi- 
cates the  first  tube  is  oscillating. 

This,  of  course,  is  done  with  the  regen- 
erative condenser  set  at  zero.  Now,  by 
adjusting  the  neutralizing  condenser,  the 
first  tube  can  be  made  to  stop  oscillating. 

A  test  to  see  whether  the  first  tube  is 
oscillating  or  not  is  to  turn  the  regener- 
ative condenser  a  slight  amount  and  then 
turn  the  second  dial  back  and  forth  over 
the  point  where  the  tube  oscillated  before. 


Note  by  Technical  Editor — Builders  of 
this  circuit  should  remember  that  any  im- 
properly neutralized  circuit,  regardless  of 
the  means  adopted  for  neutralization ,  can 
send  a  weak  current  into  the  antenna  circuit 
and  at  close  range  prove  bothersome  to  a 
neighbor.  Be  sure  the  r.  f.  tubes  are  com- 
pletely neutralized  before  going  ahead. 


CENTER 
TAP- 


The  wiring  layout  oj  Mr.  McCullah's  four  tube  receiver.  Regeneration  is  obtained  with  a  small  variable  condenser.  In  the  diagram 
above  it  will  be  noticed  that  there  is  a  small  fixed  condenser  in  series  with  the  regenerative  condenser,  for  the  reason  the 
so-called  regenerative  condenser  has  too  high  a  zero  capacity  to  prevent  the  detector  tube  from  oscillating  at  the  lower  end  of  the  scale 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


11 


How 

to  Make 

.     a 

Vacuum 
Tube 
Tester 


By  H.  FRANK 
HOPKINS 


A  GREAT  many  radio 
fans  of  today  arecon- 
stantly  asking  how 
they  can  improve  on  their 
equipment  and  how  they 
can  reach  out  and  bring 
in  the  distant  stations  strong  enough  to 
work  the  loud  speaker  and  yet  maintain 
maximum  tone  quality.  Knowing  that 
to  add  amplifying  units  tends  to  distort 
the  signal  and  produce  excessive  local 
noises,  therefore  other  means  to  attain 
efficiency  with  the  present  equipment 
are  constantly  in  demand. 

Efficiency  with  matched  parts  is  a  big 
step  toward  getting  the  utmost  out  of  a 
set.  A  way  to  match  and  measure  the 
various  parts  of  a  receiving  set  was  de- 
scribed by  the  writer  in  the  February 
RADIO  AGE,  when  a  slide  wire  bridge 
was  outlined.  From  the  number  of  in- 
quiries and  reports  of  results  obtained 
with  that  instrument,  it  is  evident  that 
the  set-builder  of  the  present  is  more 
interested  in  the  art  and  theory  of  radio 
than  in  just  putting  a  bunch  of  parts 
together  to  build  a  receiver  and  listen  to  a 
few  programs. 

He  is  an  experimenter,  gaining  knowl- 
edge in  addition  to  amusement.  Often- 
times he  contributes  valuable  informa- 
tion to  the  radio  science.  It  is  to  this 
type  of  radio  fan  that  we  look  to  for  the 
future  development  of  radio,  for  he  accom- 
plishes as  much  as  the  professional  radio 
engineer. 

A  Little  Study  Necessary 
TT  is  not  necessary  that  one  have  an 
-^advanced  education  in  electricity  or 
radio  engineering  to  apply  science  in  his 
experiments,  or  to  know  why  he  gets 
certain  results.     With  a  little  studv  and  a 


Proper 

Knowledge 

of  Tubes' 

Capacity 

and  Worth 

Will  Save 

Fan  Much 

Trouble  in 

Operation 

oj  His  Set; 

Many  Ways 

of  Operating 

Tester  Shown 


Fig  1.  A  front  view  of  the  vacuum  tube  tester,  ivhich  can  be 
made  by  any  fan.  Each  part  is  so  placed  to  give  maximum  effic- 
iency, and  no  parts  are  used  that  will  not  be  necessary.  The  tester 
is  compact  as  well  as  attractive,  and  may  be  constructed  for  port- 
able or  stationary  use. 


few  instruments,  he  has  a  great  field  open 
to  him,  and  the  writer  is  sure  that  when 
he  meets  problems  beyond  his  capacity, 
which  will  be  few,  he  need  only  seek  the 
counsel  of  authors  of  technical  radio 
articles,  and  they  will  be  only  too  pleased 
to  help  him  out. 

The  most  vital  parts  of  a  receiving  set 
are  the  vacuum  tubes.  They  are  the 
heart  of  the  system.  When  they  cease  to 
function  efficiently,  all  of  our  other  efforts 
are  in  vain,  our  matched  parts  cannot 
produce  that  which  is  not  applied  to 
them  and  they  can  only  pass  and  produce 


WIRING  TABLE 

Run  One  Lead  from 

TO — 

Binding  Post  B90 

Switch  point  No.  4 

Binding  Post  B  67'J 

Switch  point  No.  3 

Binding  Post  B45 

Switch  point  No.  2 

Binding  Post  B22U 

Switch  point  No.  1 

Binding  Post  B  — 

Binding  Post  A  + 

Binding  Post  B  — 

Terminal  lOOonPF 

Binding  Post  B  — 

Switch  point  -f- 

Binding  Post  A  + 

Terminal  F  +  on  T 

Binding  Post  A  — 

Switch  point  — 

Binding  Post  A  — 

Terminal  No.    10  on 

PF 

Binding  Post  C  + 

Terminal  No.l  on  GP 

Binding  Post  C  4- 

Terminal  No.O  on  BS 

Binding  Post  C  — 

Terminal  No. 3  on  GP 

Terminal  No.O  on  PS 

Terminal  No.l  on  BR 

Terminal  No.O  on  BS 

Terminal  +  on  GM 

Terminal  No.  2  on  GP 

Terminal  G  on  T 

Terminal  G  on  T 

Terminal  No.2  on  GS 

Terminal  No. 2  on  BR 

Terminal  4-  on  MA 

Terminal  No.  2  on  BR 

Terminal  No.4  on  TS 

Terminal  —  on  GM 

Terminal  No.l  onGS 

Terminal  —  on  MA 

Terminal    P    on    T 

Terminal  No.  2  on  R 

Terminal    No.  10  on 

PF 
Terminal  1  on  R 

Terminal  F  —  on  T 

Terminal  F  4-  on  T 

Terminal  No. 3  on  TS 

Terminal  +  on  TS 

Terminal    +    on    PF 

results  equal  in  quality  as 
that  applied  to  them.  If 
the  vacuum  tube  fails  to 
deliver,  the  output  will 
suffer  in  both  quality  and 
volume.  If  the  tubes  do 
not  match  up;  that  is,  if  they  do  not  have 
characteristics  similar  to  one  another, 
they  cannot  be  expected  to  pull  together 
and   produce  satisfactory  results. 

The  tube  problem  becomes  more  com- 
plicated day  by  day  as  new  tubes  are 
put  on  the  market.  Not  that  these  new 
tubes  are  inferior,  for  their  quality  is 
every  bit  as  good  as  can  be  obtained,  but 
their  characteristics  are  not  the  same. 
One  brand  may  not  have  as  great  an 
impedance  as  another;  maximum  ampli- 
fication may  be  obtained  on  one  make  of 
tube  at  a  different  plate  voltage  or  grid 
bias  than  on  another.  Such  tubes  can- 
not be  expected  to  "co-operate"  when  the 
same  plate  voltage  and  grid  bias  are- 
applied  to  them.  Therefore,  some  meth- 
od of  matching  tubes  or  determining  just 
where  their  critical  point  lies  is  obviously 
necessary. 

Pulls  Others  Down 

VACUUM  tubes  wear  out,  too.  The 
same  as  everything  else,  and  as  it 
passes  its  efficient  stage,  it  pulls  all  of 
the  others  down  with  it  by  making  it 
necessary  to  increase  the  filament  volt- 
age to  obtain  a  satisfactory  output. 
The  others  consequently  age  very  rapidly, 
making  it  necessary  to  replace  all  of  them 
in  a  short  time  instead  of  replacing  just 
one  of  them  when  it  passes  its  useful 
period.  This  was  described  in  the 
article  entitled  "Regulating  Filament 
Energy"  in  the  April  RADIO  AGE. 
One    such     case   would   cost    the    fan 


12 


RADIO  AGE /or  May,  1925 


The  Magazine  of  the  Hour 


O-'O-.'CC     SCALE 
VOLTMETER 


30"  VERNIEK 
RHEOSTAT. 


V/tCUi/M      TUBE 


DIAGRAM 
TEST    SET. 


3ooow  GRAPHITE 
RHEOSTAT. 


Fig.  2.      Wiring  diagram  for  M, 
efficiency  and  worth  are  unlimited. 


:  Hopkins'   lube  tester.       This 
Voltmeters  of  the  highest  rating 


layout   is  so   simple   any  radio  fan 
were  used  in  this  unit. 


can  follow   it,    and  yet  its 


almost  as  much,  if  not  more,  than  a 
good  tube  tester.  This  would  not  be 
so  inconveneint  if  it  would  only  happen 
once,  but  it  continues  to  happen,  while 
the  investment  in  a  tube-tester  is  like 
insurance  on  your  tubes,  in  addition  to 
the  benefits  you  will  reap  in  acquiring 
more  knowledge  about  your  equipment. 
In  this  way  you  will  be  able  to  weed  out 
the  weak,  inefficient  tubes  and  match  the 
good  ones  for  efficient  operation. 

The  tube  tester  to  be  described  is  not 
expensive.  Its  total  cost  is  not  much 
more  than  six  dollars  more  than  the  cost 
of  the  meters,  and  these  instruments  may 
be  purchased  from  any  reliable  dealer 
at  about  seven  dollars  each. 

The  meters  used  in  the  set  to  be  de- 
scribed were  the  best  that  could  be  ob- 
tained for  this  purpose,  and  they  are 
standard  equipment.  In  listing  the  bill  of 
materials  for  this  set,  all  of  the  parts  are 
given  a  designating  letter  or  sign,  which 
is  used  throughout  the  article  to  enable 





— 


ie»rt?'  mini    &&?&    ~^i^-~. 

WATT..  .t?/?z*?iE£  2°--.  $?£ 


Fig.  3.      A   typical    plate    characteristic 
curve  for  the  199  type  (3  volt)  tube. 


the  prospective  builder  to  understand 
the  place  of  the  parts  in  the  circuit  and  to 
simplify  the  wiring. 

A  case  or  cabinet  8  1-2  inches  by  11 
inches  and  5  inches  deep  will  be  required 
if  this  is  to  be  a  portable  set;  or  just  a 
panel  10  inches  by  14  inches  by  3-16 
inches  thick  with  the  necessary  mounting 
brackets  if  it  is  to  be  used  as  a  permanent 
fixture.  The  panel  for  the  case  will  be 
8  1-2  inches  by  11  inches  by  1-8  inches  or 
3-16  inch  in  thickness.  It  will  be  drilled 
to  mount  the  equipment  as  shown  in  the 
photograph  accompanying  this  article. 
No  dimensions  are  given  for  drilling  the 
panel,  as  there  is  a  large  selection  of 
equipment,  all  different  in  shape,  and  all 
can  be  used  with  equal  success.  Accord- 
ingly, the  size  of  the  holes  may  vary, 
but  the  layout  of  the  panel  is  not  altered, 
nor  is  it  difficult. 

The  Parts  of  the  Instrument 

1  Two  scale  voltmeter.  (0  to  10  and  0 
to  100  scale.)  PF  for  plate  and  filament 
voltage. 

1  Voltmeter  (10-0-10  scale)  GM  for 
measuring  grid  bias  voltage. 

1  Milliammeter  (0 to 30 scale)  MA  for 
measuring  plate  current. 

1  Jack  switch,  GS,  for  grid  voltmeter. 

1  Two  way  transfer  switch,  TS,  for 
PF  meter. 

1  30-ohn  vernier  rheostat,  R,  for  fila- 
ment control. 

1  3000-ohm  graphite  resistance,  BR, 
for  "B"  or  plate  battery  control. 

1    400    ohm    potentiometer,    GP,    for 
grid  bias  control. 
1  201  typ=  socket,  T,  with  metal  shell. 

1  Adapter  for  199  tubes  (If  required.) 

1  Adapter  for  WD  type  tubes  (If 
required.) 

2  Induction  switch  levers  and  knobs, 
BS,  and  PS. 


6  Switch  points,  BS  1,  2,  3,  and  4. 
PS+and-. 

10  Binding  posts,  B90,  B67  1-2,  B45, 
B22  1-2.  B-,A+,A-,C+,C+-,and 
C-. 

Miscellaneous  mounting  screws,  ter- 
minals, wire  arid  solder. 

Wiring    the    Set 

\\^HEN  all  of  the  instruments  have 
'  *  been  secured  and  the  panel  laid 
out  and  drilled  with  the  instruments 
mounted  on  it,  the  next  step  will  be  to  wire 
it  up.  The  method  to  do  this  is  with 
Number  14  B  and  S  gauge  rubber-covered 
stranded  wire,  each  wire  having  a  ter- 
minal soldered  to  each  end.  These  term- 
inals will  be  securely  bolted  to  the  posts  _ 
on  the  instruments.  Care  should  be 
taken  to  see  that  the  soldering  is  secure 
and  makes  a  good  connection,  and  that 
the  lugs  and  terminals  are  clean  and  have 
(Turn  to  page  56) 


Fig.  4.  Typical  grid  characteristics  for 
199  type  (3  volt)  tubes  at  45-80  and  90 
volts  "B"  battery. 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour  13 


A  POWER  SUPPLY  Receiver 

By  BRAINARD  FOOTE 


Does  the  ap-     *'■■■; 
pearance  please     W% 
you?     "Two     lllp 
hand"    tuning 
control,     with     % 
vernier  dials,     f 
an  R.  F.  coup- 
ling   adjust-      % 
mentforsensitiv-     ' 
ity  and  the   crys-  ▼ 

tal     control-handle 
form  the  only  visible 
parts  of  the   receiver.      % 
Station  calls  arelettered     %_ 
on    the   dials.     A   push 
switch  in  the  power  line 
turns    the    set  on  and  off. 


How  to  Make  a  Receiver  that  Draws  Both  Plate  and 
Filament  Voltage  from  Lighting  System;  Not  for  DX 


THE  application  of  alternating  cur- 
rent for  supplying  energy  for  both 
filament  and  plate  circuits  of  a 
receiving  set  is  distinctly  new  and  rather 
"tricky."  It  is  comparatively  easy  to 
devise  a  rectifying  system  for  furnishing 
satisfactory  plate  voltage  to  replace  the 
dry  cell  type  of  "B"  batteries,  but  the 
addition  of  the  house  lighting  system 
for  lighting  the  tubes  as  well  is  a  more 
complicated   matter. 

However,  the  incomparable  conven- 
ience of  a  never-failing  power  supply 
appeals  to  everyone.  Dead  batteries 
usually  show  up  just  when  you've  invited 
the  next-door  neighbors  in  for  a  special 
program  of  Metropolitan  singers,  or 
during  the  Sunday  evening  concert. 
And  "B"  batteries  must  be  frequently 
replaced  as  they  become  exhausted. 

Inasmuch  as  the  alternating  current 
can  easily  be  changed  to  direct  current 
of  any  desired  voltage  for  the  "B"  cir- 
cuit, the  "B"  voltage  supply  is  composed 
of  direct  current,  as  usual,  with  a  battery. 
But  for  the  filament,  on  the  other  hand, 
rectification  of  suffcient  current  for  tube 
illumination  would  entail  a  large  amount 
of  rectifier  and  filter  apparatus  that  would 
make  the  storage  battery  and  charger 
the  more  logical  and  convenient  filament 
power  supply  system,  to  say  nothing 
of  the  cost  of  such  equipment. 


Pictures  by  the  Author 


HOWEVER,  by  correctly  arranging 
the  "grid  return"  leads,  the  hum 
ordinarily  caused  by  60  cycle  lines  is 
balanced  out  to  such  an  extent  that  it 
is  scarcely  noticeable.  There  are,  how- 
ever, some  limitations  upon  the  types 
of  circuit  which  may  be  successfully 
used  with  the  A.  C.  supply  system,  and 
moreover,  upon  the  extent  of  the  set's 
receiving  range.  These  requirements 
tend  to  restrict  the  use  of  the  system 
to  listeners  who  care  more  about  the 
reception  of  programs  from  the  nearer 
stations  and  who  are  more  interested 
in  perfection  of  musical  reproduction 
than  they  are  in  the  search  after  far  away 
broadcasts. 

A  tube  detector,  unless  it  be  supplied 
with  filament  current  by  a  storage 
battery  or  separate  dry  cell,  is  ruled  out 
from  the  start.  This  means  that  a 
crystal  detector  is  essential.  From  the 
standpoint  of  extreme  sensitivity,  this  is 
certainly  a  handicap,  but  for  clarity  of 
reception  no  one  can  question  the  crys- 
tal's superiority  over  the  tube  for  detec- 
tion purposes.  And  with  the  plentiful 
supply  of  new  crystal  detector  stands 
comprising    either    zincite    and    bornite 


or  zincite  and  tellurium,  a  detector  that 
is  rugged  and  long-lasting  may  be  easily 
obtained.  The  dual  mineral  type  of 
detector  is  ideal  for  such  a  receiving  set, 
inasmuch  as  its  adjustment  is  made  in  a 
second  and  that  adjustment  is  held  for 
long  periods  of  time— often  several  weeks 
on    end. 

The  amplifying  tubes  can,  with  per- 
fect success,  be  lighted  on  A.  C,  so  that 
the  set  may  employ  tubes  for  amplifying 
purposes  in  practically  any  combination, 
provided  the  detector  be  a  crystal.  To 
gain  the  best  results,  the  circuit  should 
not  be  reflexed,  since  there  are  certain 
uncertainties  about  reflex  sets  that  often 
cause  trouble  when  run  on  alternating 
current.  The  most  satisfactory  all- 
around  circuit  is  a  combination  of  one 
step  of  radio  frequency,  a  crystal  de- 
tector and  two  steps  of  audio  frequency, 
with    no   provision    for   headphones. 

For  Loud  Speaker  Only 

TN  OTHER  words,  the  completed  set 
■*-  is  one  intended  solely  for  loud  speaker 
reproduction.  It  is  a  simple  set  to 
operate,  with  two  tuning  controls  and 
one  sensitivity  control.  There  is  also 
the  crystal  detector  adjustment  knob 
which  must  be  touched  occasionally. 
Stations  within  fifty  miles  are  considered 
"locals"  when  received  on  a  fair  outside 


14 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


How  the  baseboard   is  laid  out,   showing    the    wiring   completed   except  for  the  coils. 
The  layout  isn't  so  large,  when  you  consider  the  fact  that  no  external  "A"   or   "B"    bat- 
teries are  necessary.     The  base  measures  12  by  20  inches. 


antenna,  and  those  within  twenty-five 
miles  are  "locals"  when  a  small  indoor 
aerial  is  used.  The  selectivity  is  very 
satisfactory,  so  that  some  distant  stations 
may  be  heard  while  locals  are  on  the  air, 
and  quite  a  lot  of  pleasing  DX  work 
can  be  accomplished  when  locals  do  not 
interefere  seriously.  This  means  that 
while  the  set  is  chiefly  meant  for  local 
reception  with  perfect  clarity  and  plenty 
of  "pep,"  DX  stations  are  also  within 
reach,  though  not  to  the  same  extent 
as    with    a    receiver    expressly    intended 


for   DX  work  like  the  super-heterodyne 
and  various  other   "dynes." 

One  illustration  shows  the  baseboard 
of  a  power  supply  receiver  built  for  use 
with  a  cabinet.  Another  view  shows 
how  the  completed  set  appears  and  gives 
some  idea  of  its  attractiveness  and  simple 
control.  The  circuit  selected  is  presented 
as  a  result  of  a  great  deal  of  experiment- 
ing in  search  of  a  circuit  with  plenty  of 
sensitiveness  and  adaptable  to  all  sorts 
of  aerials,  from  a  long  high  wire  over  ISO 
feet   from  end   to   end   down   to   a   mere 


capacity  plate  on  which  the  house  tele- 
phone is  placed.  The  sloping  type  of 
cabinet  is  chosen  for  reasons  of  tuning 
convenience  and  better  illumination  of 
the  dials,  and  for  the  better  appearance 
as    well. 

To  house  the  necessary  apparatus, 
the  baseboard  measures  20  inches  long 
by  12  inches  deep.  On  it  are  the  tuning 
apparatus,  except  condensers  and  de- 
tector, the  audio  amplifier,  the  "B" 
voltage  rectifier  and  the  filament  current 
supply  system.  Thus,  the  only  external 
connections  or  parts  needed  are  1,  The 
aerial;  2,  The  ground;  3,  The  loud 
speaker;  4,  A  cord  and  plug  to  the  base 
receptacle  or  other  lighting  socket. 

To  avoid  ugly  wires  in  front,  the 
speaker  leads  are  inserted  through  the 
rear  and  at  the  left  end  of  the  board, 
the  flexible  cord  is  placed  at  the  rear 
center,  while  the  aerial  and  ground  wires 
emerge  at  the  rear  right.  A  push  switch 
is  inserted  in  the  flexible  cord  at  about 
a  twelve-inch  distance  from  the  cabinet, 
for  turning  the  power  on  and  off. 

The  Parts  Necessary 

CO  LONG  as  high  grade  apparatus  is 
^  selected,  there  are  no  special  require- 
ments as  to  the  parts  selected,  with  the 
exception  of  the  A.  F.  transformers. 
Three  of  these  are  used  in  the  "B" 
rectifying  system  and  they  must  be 
rigidly  assembled,  with  clamps  or  ma- 
chine screws  tightly  holding  the  lamina- 
tions of  the  core  at  several  points.  If 
you  can  wiggle  the  core  pieces  with  your 
finger,  they  cannot  be  used  for  the  "B" 
part  of  the  set,  though  they  may  be  used 
for  the  audio  amplifier  well  enough. 
(Turn  to  page  48) 


.O04 


001s 


CUV5TA1- 


Complete  wiring  for  a  receiver  operated  on  the  A.   C.  house  current.       The  only  battery  used  is  a  4  1-2  volt  "C"  battery — this  being 
included  in  the  set.      There  are  five  tubes  in  all;  it's  a  three  tube  and  crystal  detector  set,   the  extra  two  tubes  furnishing  the  rectified 

current  for  the  "B"  voltage. 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour  15 


Now  s   the  Time  for  a  Radio 
House-Cleaning 


By  PAUL 
GREEN 


An  Ail-Around 

Overhauling  Needed 

If  Your  Set  is  to  Work 

Efficiently  This  Summer 


FOR  FIVE  months  or  more,  radio 
reception  has  been  good.  Aside 
from  charging  the  "A"  battery, 
most  of  us  have  given  our  sets  little  or 
no  attention  since  last  Fall.  Now,  how- 
ever, we  hear  on  every  hand  complaints 
of  reception  falling  off.  By  this  time 
next  month  a  large  majority  of  radio 
listeners  will  have  pessimistically  ac- 
cepted the  situation  as  unalterable  and 
let  it  go  at  that. 

In  spite  of  this,  broadcasting  stations 
have  been  for  many  months  planning 
wonderful  programs  and  greater  power 
for  the  coming  Summer.  If  reception 
continues  to  grow  poorer  as  the  season 
advances,  will  all  this  planning  accom- 
plish anything?  Isn't  it  just  so  much 
wasted  effort?  you  ask.  Well,  perhaps 
we  have  formed  hasty  conclusions  as 
to  the  effect  of  warmer  weather  on  re- 
ception.    Let  us  see. 

Do  you  recall,  last  Fall,  when  you  put 
the  old  set  in  trim  for  the  Winter,  how 
among  the  things  you  did,  perhaps  you 
purchased  a  new  set  of  "B"  batteries 
and  a  tube  or  two  and  just  for  luck  re- 
soldered  some  of  the  joints.  You  knew 
that  others  were  getting  results;  there- 
fore, your  failure  to  do  so  argued  the 
need  of  attention  to  your  set.  Well, 
anyway,  you  got  the  set  to  "perking" — 
and  it  has  continued  to  do  so  for  several 
months.  Well,  here  we  are  "at  the  end 
of  our  radio  season,"  and  what  do  you 


propose  doing?  Desert  your  old  stand-by? 
And  just  when  it  needs  your  attention, 
too. 

Weather  Gets  the  Blame 

THE  average  set  has  seen  a  total  of 
not  less  than  six  hundred  hours' 
service  since  last  it  received  any  real 
attention.  During  that  time  batteries, 
contacts,  joints  and  tubes  have  under- 
gone changes.  Even  if  Winter  were  to 
continue,  these  parts  would  need  atten-. 
tion.  But,  in  common  with  many  other 
fans,  you  probably  have  overlooked 
examining  your  set,  charging  the  weather 
with  the  "falling  off"  instead. 

Certainly,  with  all  these  wonderful 
radio  programs  ahead  of  us,  it  is  very 
worth  while  to  do  what  we  can  to  assist 
our  sets  to  give  us  their  best.  Following 
are  some  of  the  complaints  to  which  a 
set  may  be  subject  at  this  time  of  year, 
with  hints  for  remedying  the  complaints. 
An  aerial  which,  perhaps,  gave  very 
good  service  all  Winter  long  may  now 
hang  too  close  to  trees  and  shrubbery. 
As  the  foliage  comes  out,  the  absorption 
problem  grows  more  serious  and  the 
aerial  must  be  given  more  clearance. 
An  examination  will  usually  show  that 
it  can  be  rehung  more  advantageously. 
While  doing  so,  see  that  the  insulators 
are  clean  and  free  from  carbon  deposit. 
If  they  are  of  a  porous  design,  change 
them  for  the  glazed  type.     The  lead-in 


should  hang  tree  and  clear  of  other 
objects.  It  must  be  well  insulated  where 
it  enters  the  building.  Be  sure  that  the 
joint  between  the  lead-in  and  aerial  is 
a   good  one. 

There  are  a  number  of  changes  that 
may  have  taken  place  in  the  set  since 
last  Fall.  Unless  the  joints  were  soldered 
with  rosin  core  solder  or  carefully  wiped 
after  soldering,  many  of  them  will  be 
found  corroded  or  coated  with  a  copper 
salt.  Flux  often  spreads  to  the  panel 
and  forms  a  partial  short  circuit,  the 
effect  of  which  becomes  more  and  more 
apparent  as  warmer  and  damper  weather 
approaches.  Clean  such  parts  with 
benzine  and  alcohol.  Unless  the  rotors 
of  your  condensers  are  provided  with 
flexible  "pig  tails,"  it  is  well  to  clean  the 
points  of  contact  with  fine  emery  cloth. 
Dust  between  the  plates  with  a  pipe 
cleaner  to  remove  dust  particles  and 
lint.  If  left  in,  they  tend  to  collect 
moisture  and  cause  leakage  between 
plates.  This  cuts  down  volume  and 
makes  the  set  noisy. 

Look  for  Broken  Joints 

WITH  a  pair  of  phones  on  your  ears 
and  the  set  in  operation,  go  over 
it  for  broken  joints.  Tap  each  point 
separately  with  a  lead  pencil.  With  the 
head-set  still  on,  test  each  movable  part. 
If  sudden  clicks  are  heard,  it  is  a  sure 
indication  of  broken  joints  or  loose  con- 


16 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


The  picture  shows  a  good  example  of  how  neat  wiring  should  be  accomplished.  A 
compact  wiring  job  like  the  above  will  withstand  the  tests  of  time.  Unless  your  set  joints 
were  carefully  soldered,  the  chances  are  that  warm  weather  will  have  corroded  them.  The 
remedy  is  to  clean  such  parts  with  benzine  and  alcohol.  Brush  between  plates  to  remove 
dust,  which  will  cause  leakage  if  you  do  not  watch  out. 


tacts.  In  case  of  loose  joints,  re-soldering 
will  correct  the  trouble.  Tightening 
nuts  will  usually  correct  the  other. 

Those  of  us  who  are  using  storage  "A" 
batteries  know  that  they  must  be  re- 
charged at  intervals.  We  have  come  to 
recognize  the  symptoms  which  say — 
"low  battery,"  and  so  little  need  be  said 
on  this  score.  But  it  is  usually  a  fact 
that  "B"  batteries  are  allowed  to  get 
low  before  new  ones  are  purchased. 
They  should  be  tested  frequently  and 
as  soon  as  the  voltage  has  dropped  ten 
or  twelve  per  cent,  thrown  away.  Under 
such^conditions  it  will  usually  be  found 
that  the  amperage  has  dropped  to  a  very 
low  figure.  For  this  reason,  it  is  not  safe 
to  allow  the  "B"  battery  to  fall  off  much 
more,  especially  if  yours  is  a  set  having 
more  than  two  tubes. 

Like  the  storage  battery,  the  tube 
becomes  run  down  and  after  a  Winter's 
use  it  is  in  no  condition  to  detect  properly 
and  amplify  the  weaker  signals  .of  sum- 
mer-time. The  tubes  are  responsible 
for  much  of  the  falling  off  that  we  have 
attributed    to    the    weather. 

The  effective  life  of  a  tube  is  not  de- 
termined by  the  length  of  time  it  can 
be  used  without  burning  out.  Long 
before  this  occurs,  most  tubes  cease  to 
be  efficient.  To  offset  this  gradual 
falling  off,  the  filament  is  burned  brighter. 
This  still  further  hastens  the  tube's 
demise.  Is  it  at  all  strange,  then,  that 
as  Spring  passes  and  Summer  comes  we 
find  our  sets  almost  useless  so  far  as 
coping  with  the  more  difficult  broadcast 
conditions    is    concerned? 

So  much  for  cause  and  effect — we  have 
remedied  the  other  troubles;  now  what 
can  we  do  for  the  tubes? 

When  it  was  said  that  the  tube,  like  the 
battery,  runs  low,  the  analogy  should 
have  been  carried  one  step  farther  and 
the  statement  made  that  the  tube,  like 
the  battery,  can   be  recharged. 


ORACTICALLY  everyone  of  us  has 
-*-  noted  the  instructions  which  come 
with  tubes,  for  rejuvenating  them.  A 
few  of  us  have  tried  these  instructions, 
but  so  far  as  the  writer's  experience  goes, 
no  one  ever  "brought  his  tubes  back" 
by  such  a  procedure.  This  is  accounted 
for  by  the  fact  that  very  few  fans  have 
the  proper  instruments  for  regulating 
or  measuring  the  applied  filament  cur- 
rent. 

A  Step  Forward 

Within   a  short  time  instruments  will 
be    made    available    to    all    fans    for    re- 


juvenating their  tubes.  Tests  with  this 
equipment  reveal  some  very  interesting 
facts.  Tubes  which  have  long  since 
passed  their  period  of  usefulness  can  be 
brought  back  to  apparently  full  normal. 
This  also  applies  to  tubes  which  have 
been  paralyzed  by  excess  filament  volt- 
age. 

Frequently  brand  new  tubes  will  show 
a  marked  improvement  after  treatment. 
In  a  number  of  tests,  rejuvenation  has 
made  the  tube  noticeably  superior  to 
new  tubes.  Paralyzing  a  tube  and  bring- 
ing it  back  to  life  has  been  repeated  as 
high  as  thirty  or  forty  times  without 
noticeably  ill  effects  of  any  kind. 

Heretofore,  our  tubes,  like  dry  batter- 
ies, were  discarded  when  their  effective 
life  had  passed.  Now  that  we  can  re- 
charge them  just  like  storage  batteries. 
Let's  make  this  a  real  radio  Spring  and 
Summer  and  enjoy  the  wonderful  pro- 
grams planned  for  us. 

And  while  you're  cleaning  up  and 
tightening  up  your  set,  you  might  cast 
an  eye  around  the  room  in  which  it  is 
located  and  tidy  that  up  a  bit.  Nothing 
so  irks  a  well-meaning  housewife  as  to 
find  hubby's  or  son's  radio  apparatus 
strung  all  over  the  bedroom,  dining 
room,  kitchen,  or  wherever  the  set  hap- 
pens to  be  located. 

So  for  the  good  of  all  dispositions  con- 
cerned, clean  out  all  unnecessaay  parts 
and  stow  them  away  for  future  use.  And 
while  you're  doing  that,  see  that  your 
aerial  lead-in  from  the  set  to  the  window, 
and  the  ground  connection  are  in  good 
shape,  for  these  vital  factors  of  a  set's 
operation,  when  not  inspected  from  time 
to  time,  may  develop  faults  that  do  seri- 
ous damage  to  the  receiver. 

(Note:  Mr.  Green  will  be  glad  to  supply 
detailed  information  regarding  the  tube 
rejuvenator  to  all  readers  of  RADIO  AGE 
who  will  address  him  care  of  this  magazine.) 


How  a  tube  rejuvenator  works.     Such  an  instrument  will  renew  the  201A  and  301 A 

as  well  as  the  UV199  and  C-299  tubes  in  less  than  eleven  minutes,  it  is  claimed.    As  no 

maters  are  necessary,  hosts  of  fans  will  find  this  set  easy  to  build. 


RADIO  AGE  for  May,   1925 


The  Magazine  of  the  Hour 


19 


An  unusual  photo  showing  a  rear  panel  view  of  Mr.  Calcaterra's"  8-tube  super-heterodyne, 
though  utilizing  every  inch  of  space,  is  not  crowded. 


Note  the  compact  arrangement,  which. 


A  PRACTICAL  SUPER-HET 

A  UNIQUE  8-TUBE  OUTFIT  ON  AN  18-INCH  PANEL 


GOSSIP  for  months  past  has  been 
-  to  the  effect  that  the  super- 
heterodyne circuit,  the  "king  of 
all  radio  receivers,"  has  been  taken  out 
of  the  mystic  precincts  of  the  laboratory 
and  made  into  a  practical  proposition 
for  the  average  set  user.  Yet  it  cannot 
be  said  that  all  of  this  gossip  has  been 
accompanied  by  any  too  much  definite 
information  in  the  way7  of  diagrams  and 
panel  layouts  which  would  enable  set 
builders  to  turn  out  a  super  to  grace  the 
parlor  rather  than  the  laboratory — with 
respect  to  consistent  reliability  as  well 
as  appearance. 

Supers  have  been  in  general  great 
eaters  of  battery  current,  as  well  as 
occupiers  of  an  ungainly  amount  ot 
space.  In  the  attempt  to  cut  down  the 
battery  consumption,  complications  have 
been  introduced,  such  as  reflexing,  which 
are  hardly  improvements  from  the  stand- 
point of   simplicity. 

The  super  here  described  is  unique 
in  at  least  some  of  these  respects.  Em- 
bodying the  full  eight  tubes  of  the 
standard  Armstrong  circuit,  with  each 
transformer  separate  so  that  it  can  be 
tested  and  interchanged  independent 
of  any  other  part,  the  entire  set  mounts 
neatly  on  a  7x18  inch  panel  and  a  7x17 
inch  sub-panel,  so  that  it  fits  any  stand- 
ard 18-inch  cabinet.  And  if  some  of  the 
veterans  of  supers  of  former  years  are 
inclined  to  look  askance  at  the  "crowded" 
arrangement  of  instruments  and  ask 
questions  about  inter-stage  coupling. 
the  writer  can  only  answer  that  such 
inter-stage  coupling  has  simply  not  put 
in    appearance. 


By  Joseph  Calcaterra 


BILL   OF   MATERIALS 

FOR  THE  SET 

Re 

ference 

1  Front  Panel,  7"xl8"x3-16". 

Numbers 

1  Sub-Panel.  7"xl7"xl-8" 

1  Binding-Post     Panel,  1M"x17"x 

3-16" 

1  Cabinet  for  7"xl8"  Panel,  7  or  8 

inches  deep. 

1. 

2 

2  Low-loss     Variable     Condensers, 
.0005  mfd. 

3 

1  Rheostat,  30  Ohm. 

4 

1  Rheostat,  6  Ohm. 

5. 

12 

1  pair  Shelf-Supporting  Brackets. 

6 

1  Midget  Variable  Condenser. 
.000045  mfd. 

7, 

42 

2  By-pass  Fixed  Condensers,  1  mfd. 

8 

1  Brass  Angle  Bracket,  each  leg  1 
inch   long:    hole   in   each   leg    $i 
inch  from  the  bend.     (Standard 
brass  bracket  obtainable  at  most 
radio  or  hardware  stores.) 

9, 

11 

2  Single-Circuit  Jacks. 

10 

1  A  Battery  Switch. 

13 

1  Fixed  Condenser,  .005  mfd. 

14 

16 

2  Laboratory-grade    Audio    Trans- 
formers. 

IS 

17, 

18, 

!■  8  Sockets    for    UV-199    or    C-299 

20 

21, 

22, 

23, 

24 

j       tubes. 

19 

25 

2  Fixed  condensers  with  grid  leak 
mounting  clips. 00025  mfd. 

19 

1,  2  megohm  grid  leak. 

25 

1,  5  megohm  grid  leak. 

26 

1  Type    R-130    Radio    Frequency 
Coupler. 

27 

28, 

29 

3  Type   R-110  Long  Wave   Radio 
Frequency     Transformers. 

30 

1  Type  R-120  10,000  Meter  Tuned 
Radio  Frequency  Transformer. 

2  Vernier  Dials. 

31, 

32, 

33 

3  Binding      Posts      with      "Loop" 
marking. 

34 

35 

2  Binding  Posts  with  "C  Batt — " 
marking. 

36. 

37, 

38 

f  6  Binding    Posts,    one    of  each    of 
following: 

39. 

40, 

41 

Markings:  "C  Batt — ":  "A  Batt 
— ":  "A  Batt+";  "B  Batt — "; 
''B  Det-r".  "B   Amp.+" 

'T'HE  instruments  have  been  very  care- 
-'-  fully  designed  to  permit  mounting 
in  a  small  space,  without  interfering 
electrically  with  each  other,  and  the 
creditable  performance  in  this  respect  is, 
therefore,  not  to  be  considered  surprising. 
It  must  not  be  forgotten,  either,  that 
even  in  super-heterodynes,  short  wires 
are  better  than  long  ones,  and  close 
mounting  permits  short  wires.  Add  to 
this  technical  advantage  the  great  use- 
fulness of  an  18-inch  set  as  compared 
with  a  40-inch  one  for  traveling  purposes 
in  the  Summer  time,  and  the  set  here 
described  needs  no  further  recommenda 
tion. 

Tone  is  Paramount 
It  should  be  remarked,  however,  that 
tone  quality  has  been  considered  para- 
mount throughout  this  design;  while 
the  selectivity  noted  is  fully  up  to  the 
best  super-heterodyne  practice,  it  is 
believed  that  the  tone  quality  obtainable, 
even  with  distant  stations,  is  a  distinct 
advance.  Two  features  contribute  large- 
ly to  this — the  use  of  broadtuned 
transformers  in  the  intermediate  stages, 
eliminating  the  necessity  of  delicate 
"matching,"  and  the  use  of  laboratory- 
grade  audio  transformers.  In  spite  of 
this  use  of  some  rather  high-priced  parts, 
the  entire  set  can  be  built  at  an  ex- 
penditure for  parts  (not  including  tubes, 
batteries,  etc.)  of  not  to  exceed  $75.00. 
Simplicity  of  control  .is  another  point 
which  has  been  carefully  worked  out 
in  this  design.  Besides  the  two  familiar 
major  controls,  there  are  only  three  minor 
ones.  Yet  the  sensitiveness  is  not  per- 
ceptibly   less    than    that    of    any    of    the 


20        .  RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


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Building  post  panel  layout — view  from  front  of  set,  inverted 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


21 


well-known,  complicated 
supers;  a  loop  antenna 
not  more  than  18  inches 
in  diameter  will  bring  in 
distant  stations. 

The  two  photographs 
show  the  appearance  re- 
spectively of  the  top  and 
bottom  of  the  set,  and 
drawings  are  given  which 
show  the  layouts  re- 
spectively of  the  back 
of  the  panel,  top  and 
bottom  of  sub-panel, 
and  binding-post  panel. 
(See  note  at  end  of 
article.) 

Parts  Shown   by 
Numbers 

A  WIRING  diagram  is 
-^*-  also  given,  on  which 
the  parts  are  identified 
by  the  same  numbers 
used  in  the  drawings. 
This  circuit  does  not  differ  very  much 
from  the  standard  circuit;  it  has  a  special 
method  of  loop  connection  by  which  a 
certain  amount  of  regeneration  is  intro- 
duced, under  control  of  a  small  variable 
condenser  (No.  6  in  drawing).  This 
sharpens  the  tuning  to  a  marked  degree. 

All  of  the  parts  used  in  a  super-hetero- 
dyne must,  of  course,  be  high-grade  in 
order  to  get  the  results  one  expects  from 
the  circuit.  It  is  not  necessary  to  use 
the  laboratory-grade  audio  transformers 
shown  in  the  pictures,  but  since  these 
are  larger  than  standard  transformers, 
the  latter  can  be  mounted  in  the  same 
space   with    no   difficulty   whatever. 

The  holes  in  the  sub-panel,  through 
which  wires  are  passed  when  making 
connections  between  terminals  located 
above  the  sub-panel  and  others  below 
the  sub-panel,  have  been  made  conspicu- 
ous by  being  blackened.  These  holes 
are  marked  by  lower  case  or  "small" 
letters  to  distinguish  them  from  terminal 
markings.  These  holes  are  not  all  shown 
in  exactly  the  best  position  in  the  draw- 
ings here  given,  as  a  few  have  been 
shifted  slightly  to  bring  them  into  view. 

It  will  be  noticed  in  the  photographs 
that  there  are  very  few  wires  visible  from 
the  top  of  the  set,  and  this  feature  adds 
greatly  to  its  appearance.  The  effect  is 
obtained   chiefly   through   the   device   of 


A  bottom  view  of  the  super-heterodyne  receiver,  showing  the  wiring  arrangement  before  the  parts  are 
installed.  After  studying  this  diagram  and  the  others  in  this  article,  the  fan  should  have  no  trouble  in 
placing  the  parts.      Every  part  is  clearly  marked  by  a  number  in  the  diagrams  on  the  opposite  page. 


reversing  some  of  the  binding  post  screws 
on  the  sockets.  All  of  these  posts  which 
are  shown  on  the  sub-panel  by  slotted 
screw  heads  instead  of  by  knurled  nuts 
are  thus  reversed,  and  the  wires  are 
attached  below  the  sub-panel.  In  some 
cases  other  connections  are  made  also 
on  top  of  the  sub-panel,  a  soldering  lug 
being  here  inserted  under  the  screw  head 
for  that  purpose.  The  reversed  terminal 
screws  going  through  the  sub-panel  are 
sufficient  to  fasten  the  socket  to  the 
panel  without  using  additional  screws 
for  the   purpose. 

After  all  of  the  parts  and  binding  posts 
are  connected  to  the  three  panels,  and 
the  binding-post  panel  is  attached  by 
metal  brackets  to  the  sub-panel,  the 
greater  part  of  the  wiring  can  be  com- 
pleted to  best  advantage  before  attach- 
ing the  front  panel.  It  is  best  to  begin 
with  all  of  the  wires  which  can  be  con- 
nected on  top  of  the  sub-panel  assembly. 
Next  the  wiring  on  the  underside  of  the 
sub-panel  should  be  completed,  and 
then  the  wires  which  run  through  the 
sub-panel,  between  terminals  located 
on  opposite  sides  of  it.  The  front  panel 
is  then  attached  and  the  remaining  wires 
connected. 

At  one  end  of  the  sub-panel  are  the 
eight  battery  terminals.  The  A  battery 
may   be   either   six   dry   cells   connected 


three  in  series,  or  preferably  a  four-volt 
storage  battery.  Binding  post  40  should 
be  connected  to  the  45-volt  B  battery 
terminal  for  the  first  and  second  detector 
tubes,  and  binding  post  41  to  the  90- 
volt  end  of  the  B  battery  for  the  ampli- 
fier tubes.  Binding  post  34  carries  a 
4)^- volt  negative  C  battery  voltage  to 
the  grids  of  the  two  audio  tubes,  while 
post  35  carries  a  3-volt  grid  bias  to  the 
intermediate  frequency  tubes. 

At  the  other  end  of  the  binding  post 
panel  are  the  three  posts  for  loop  con- 
nections. Post  32  should  connect  to  a 
tap  on  the  loop  such  that  one-fourth  of 
the  total  turns  on  the  loop  are  included 
between  posts  31  and  32. 

To  operate  the  set,  turn  on  the  battery 
switch  and  turn  the  rheostats  about 
three-fourths  of  the  way  on.  Set  the 
small  condenser,  No.  6,  at  its  minimum 
capacity  and  begin  tuning  with  the  two 
large  variable  condensers.  When  the 
set  is  working,  gradually  increase  the 
capacity  of  condenser  No.  6  to  sharpen 
up  the  tuning,  but  not  enough  to  throw 
the  detector  into  oscillation.  Rheostat 
3  should  be  turned  on  as  far  as  possible 
without  causing  loss  of  clearness  of  tone, 
and  rheostat  4  should  be  turned  down 
as  low  as  possible  without  losing  volume. 
(See  note  below) 


A  wiring  diagram  of  the  super-het.  This  receiver  does  not  differ  from  the 
standard  hookup  of  its  kind,  but  it  offers  unusual  tone  quality,  operating  best 
in  locations  about  ZOO  miles  from  powerful  broadcasting  stations. 

Note:  Persons  who  desire  to  build  this  set  can  obtain  from  the  author  complete, 
full-size  panel  lay-out  and  detailed  wiring  directions.  Enclose  10  cents  in  stamps 
to  cover  mailing  cost,  and  address  Joseph  Calcaterra,  care  of  this  magazine.  The 
author  will  be  pleased  to  hear  from  persons  who  have  built  the  set,  describing  re- 
sults obtained. 


22  RADIO  AGE  for  May,   1925 


The  Magazine  of  the  Hour 


The   Physical  Significance   of   Tuning 


By  Dr. 

Frederick 

W. 

Grover 


Who  is  a  prom- 
inent Member  of 
the  Department 
oj  Electrical 
Engineering  Oj 
Union  College, 
Schenectady,  N. 
Y.,  and  recog- 
nized authority 
on  the  subject  oj 
radio  waves 


The  Action  of 

Radio  Waves 

in  your  Set 


EVERY  radio  Ian  knows  what  is 
meant  by  tuning-in.  You  turn 
a  dial  on  the  receiving  set  until 
the  sound  is  loudest.  Without  tuning, 
only  the  local  stations  come  in,  and  it  is 
impossible  to  separate  one  station  from 
another.  We  tune  our  sets  as  a  matter 
of  course  and  naturally  give  little  thought 
to  the  actual  significance  of  what  may 
be  regarded  as  perhaps  the  most  basic 
of  radio  adjustments. 

I  am  asking  your  consideration  of  cer- 
tain analogies  which  may  be  pointed  out 
between  the  actions  in  a  radio  circuit 
and  those  in  the  more  familiar  cases  of 
sounding  or  vibrating  bodies.  Analogies 
are  helpful  in  that  they  illustrate  un- 
familiar things  by  pointing  their  like- 
ness to  things  better  known.  However, 
when  we  liken  an  electric  oscillation  of 
current  to  the  vibration  of  a  sounding 
body,  or  an  electromotive  force  to  a  me- 
chanical force,  it  must  be  remembered 
that  they  are  not  identical  things.  We 
must  use  our  imaginations  subject  to 
common  sense,  and  make  some  allow- 
ance for  points  of  difference. 

Pitch  Decides  Wavelength 

A  STRING  instrument  is  tuned  by 
carefully  tightening  a  string  until, 
when  it  is  sounded,  it  gives  off  the  de- 
sired pitch.  The  pitch  of  the  sound  is, 
however,  the  same  whether  it  is  struck, 
plucked  or  bowed.  We  say  that  the 
string  vibrates  in  its  natural  period.  The 
same  is  true  of  any  sounding  body. 
Sound  waves  go  off  from  it  through 
the  air  and  the  pitch  of  the  sound  deter- 
mines the  wavelength;  that  is,  the  dis- 
tance by  which  one  pulse  travels  ahead 
of  the  next.  Likewise  a  radio  circuit  may 
be  set  into  oscillation  by  various  means, 
but  gives  off  electrical  waves  whose  wave- 
length bears  no  relation  to  the  method 
by  which  the  oscillation  is  produced. 
The   transmitting   circuit   has   a   natural 


period  just  as  in  the  case  of  the  string. 
Whereas  the  pitch  of  the  sound  given 
by  the  string  (so  many  vibrations  per 
second)  depends  upon  its  length  and  ten- 
sion, so  the  pitch  of  the  electrical  wave 
(so  many  kilocycles  per  second)  depends 
upon  the  amount  of  inductance  in  its 
coil  and  the  capacity  of  its  condenser. 
The  analogy  between  a  sounding  body 
and  an  oscillating  electrical  circuit,  used 
for  broadcasting,  may  be  extended  to 
the  case  of  a  receiving  circuit  also.  If 
you  sing  a  single  note  forcibly  into  the 
top  of  a  piano,  you  will  obsef\  e  that  one 
of  the  strings  faintly  sings  the  same  note 
after  you.  Investigation  shows  that  the 
single  string  involved,  if  struck  in  the 
usual  way,  gives  out  this  note  and  no 
other.  Of  the  multitude  of  strings  in  the 
piano,  all  are  practically  unaffected, 
except  the  single  string  whose  natural 
period  of  vibration  agrees  with  the  period 
of  the  sound  vibrations  sung.  Shout 
another  musical  note,  and  another  string 
responds,  while  the  previous  one  joins 
the  throng  of  silent  strings.  Evidently 
the  sound  waves  of  your  voice  have 
beat  upon  all  of  the  strings  of  the  piano, 
but  are  powerless  to  produce  a  notice- 
able vibration  except  in  the  case  of  the 
string  which  is  tuned  to  the-  incoming 
sound  waves. 

How  It's  Done 

f  IKEWISE,  the  electrical  waves  pas- 
-*— '  sing  out  from  a  broadcasting  station 
produce  no  appreciable  oscillations  in  a 
receiving  circuit,  unless  its  natural  period 
of  oscillation  is  the  same  as  that  of  the 
incoming  electrical  waves.  When  we  tune 
a  circuit  to  the  electrical  waves,  it  is 
just  the  same  as  though  in  the  piano  ex- 
periment we  had  worked  upon  a  single 
string  by  tightening  it  or  loosening  it, 
until  it  responded  with  greatest  loudness 
to  the  note  sung  against  it. 

To  get  a  clear  idea  of  the  actions  in- 


volved in  the  vibrations  ol  a  sounding 
body,  let  us  consider  the  simple  case  of 
a  thin  strip  of  steel,  a  foot  long,  clamped 
at  one  end  in  a  vise.  If  the  free  end  is 
pulled  aside,  we  feel  an  elastic  force 
resisting  us,  and  this  gets  greater  the 
farther  we  pull  it  from  the  original  posi- 
tion. If  now  we  let  the  spring  go,  the 
elastic  force  causes  it  to  return  toward 
the  undisturbed  position,  and  we  observe 
that  it  will  vibrate  for  a  short  time,  send- 
ing out  pulses  into  the  air.  If  we  try 
a  much  shorter  and  stiffer  spring,  suit- 
able for  a  harmonica,  the  vibrations  are 
more  rapid  and  we  hear  a  musical  sound. 

An  explanation  of  the  vibrations  of 
the  spring  is  briefly  as  follows: — The 
spring  is  bent  aside  at  the  start,  and  when 
released,  the~elastic  force  causes  it  to 
move.  As  it  returns,  the  elastic  force 
diminishes,  and  by  the  time  the  spring 
has  reached  the  original  undisturbed 
position,  it  has  become  zero.  However, 
the  spring  keeps  on  moving  because  of 
its  momentum,  and  as  it  passes  the 
undisturbed  position  it  begins  to  bend 
the  spring  in  a  direction  opposite  to  the 
first,  thus  setting  up  an  elastic  force 
which  works  against  the  motion  of  the 
spring,  slowing  it  down  more  and  more 
until  it  comes  to  rest.  The  spring  then 
moves  back,  and  the  sequence  of  events 
is  repeated.  If  there  were  no  friction, 
the  spring  would  make  equal  excursions 
on  both  sides  of  the  undisturbed  position, 
and  once  started,  the  vibrations  would 
never  cease.  Of  course,  this  is  never  the 
case;  the  vibrations  die  down  gradually 
and  the  spring  comes  to  rest,  since  with 
each  excursion  the  effect  of  friction  is  to 
reduce  the  distance  traveled  from  the 
central  position. 

The  original  work  done  on  the  spring 

in  bending  it  aside  is  the  sole  source  of 

energy  the  spring  possesses,  and  when  this 

has   been    dissipated   in   overcoming   the 

(Turn  to  page  52) 


RADIO  AGE  for  May,  1925 


What  the  Broadcasters  are  Doing  23 


.     * 


Photo  Copyright  by  Drake  Studi< 


REMINISCENT   OF   THE   FAR  EAST— 

were  the  intimate,  quaint  talks  broadcast  recently  from  KNX, 
Hollywood,  Calif.,  by  Anna  May  Wong,  diminutive  Chinese  movie 
actress  who  has  made  such  a  "hit"  with  the  cinema  fans  throughout 
the  country.  Despite  the  fact  she's  a  native  Chinese,  Miss  Wong  talks 
like  a  typical  New  Yorker.  However,  she  is  able  to  convey  real 
Oriental  atmosphere  by  lapsing  into  Chinese  dialect  and  crooning  the 
weird  songs  of  her  native  land. 


24 


RADIO  AGE  for  May,  1925 


What  the  Broadcasters  are  Doing 


Wkat  tke 

Broadcasters 

are  Doing 


WEBW  Quartet  Gains 
Host  of  Friends 

"PHE  four  imposing  young  men  who 
■*-  are  shown  in  the  photograph  on 
this  page  compose  the  famous  Fair- 
banks, Morse  &  Co.,  Quartet  at  Beloit, 
Wisconsin,  who  broadcast  almost  every 
Tuesday  evening  from  WEBW,  in  con- 
junction with  the  Fairbanks- Morse  Con- 
cert Band.  The  quartet  recently  sang  a 
noon  hour  concert  from  WMAQ,  Chicago, 
which  many  readers  may  remember 
having  enjoyed. 

Three  Lees  and  a  Dave  make  up  this 
musical  four.  They  are:  Dave  Mc- 
Cullough,  Leland  Forman,  LeGrande 
Warriner  and  LeGrande  Brannen. 

The  first  of  the  Lees  is  Leland  Forman, 
who  sings  second  tenor  and  who  directs 
the  quartet.  The  other  two  Lees  are 
LeGrande  Warriner  and  LeGrande  Bran- 
nen, singing  baritone  and  bass  parts. 
Dave  McCullough,  the  Scotchman  who 
sings  like  an  Irish  tenor,  is  the  fourth 
member  and  ably  handles  the  top  tenor 
notes. 

"Our  Dave, "as  his  colleagues  and  thou- 
sands of  listeners  all  over  the  country  are 
calling  him,  sings  more  popular  numbers 
than  the  other  members  of  the  quartet, 
who  confine  them- 
selves al  most  en- 
tirely to  classical 
co  m  posi  t  ions. 
Dave  is  one  of  the 
most  popular  en- 
tertainersin  south- 
ern Wisconsin. 
Flappers  who  have 
been  charmed  by 
his  sweet  voice 
over  the  air  will  no 
doubt  be  disap- 
pointed and  stop 
sending  the  station 
mash  notes  when 
theylearnthat  Mc- 
Cullough is  a  hap- 
pily married  man. 
He  admits  it  him- 
self. 

Brannen     Popu- 
lar Reader 

LeGrande  Bran- 
nen, the  splendid 
bass  singer,  is  also 
a  n  accomplished 
musical  reader. 
When  the  quartet 
recently  entertain- 
ed from  Chicago, 
he  gave  a  reading 
called,  "T  h  e 
Game  of  Life." 


D 


"Dream  Daddy"  On  Air 
for  Uncle  Bob 


WJZ   Requests  Second   "Best 
Announcer"  Rating 

DE CAUSE  of  the  large  amount  of 
-"-*  public  interest  in  the  findings  of  the 
Radio  Voice  Technique  Committee  at  its 
recent  meeting,  Station  WJZ  has  re- 
quested that  the  committee  hold  another 
meeting   for   the    purpose    of   comparing 

"P\REAM  DADDY"  Harry  Davis,  one     the    announcers    of    all    stations   in    and 

*-*   of  radio's  pioneer  entertainers  and     near   New   York 

one  of  the  most  popular  jazz  artists  on 

the  air  today,  is  now  enjoying  a  new  role 

as     "pinch     hitter"     for     "Uncle     Bob," 

(Walter  Wilson),  who  has  been  delighting 

the  kiddies  during  Bedtime  Story   Hour 

at  KYW  for  the  past  few  years. 

Uncle  Bob  was  ordered  to  take  a  pro- 
longed rest  by  his  physician,  and  Harry 

Davis    volunteered     to    take     his    place 

while    the    kiddies'    popular    "Uncle"    is 

regaining  his  strength  in  California. 
And     Harry,     who     made     the     song 

"Dream  Daddy"  famous  several  months 

ago,  is  doing  well  as  the  little  tots'  lullaby 

man  from  KYW,  every  evening  between 

6:30  and  7. 

Davis  has  been  with  KYW  ever  since 

it  went  on  the  air  and  his  method  of  pre- 
senting popular  airs  is  known  from  coast 

to  coast  for  its  originality. 


York  City.  The  committee 
recently  listened  to  wax  records  of  a  rep- 
resentative number  of  announcers  and 
voted  Herbert  B.  Glover,  of  WJZ,  as  the 
best  of  those  announcers. 

Great  public  interest  has  been  shown 
in  regard  to  that  decision,  and  station 
WJZ  feels  that  the  term  "Best  An- 
nouncer" should  be  applied  only  to  the 
winner  of  research  in  which  every  an- 
nouncer has  been  examined.  Charles  B. 
Popenoe,  manager  of  Stations  WJZ  and 
WJY,  has  forwarded  the  following  letter 
to  the  committee: 

"I  am  naturally  most  pleased  that  an 
announcer  of  Station  WJZ  should  have 
received  the  highest  rating  at  the  recent 
meeting  of  the  committee.  The  fact 
that  the  winning  percentage  was  only  66 
out  of  a  possible  100  shows,  however, 
that  there  is  still  much  room  for  improve- 
ment   in    the    an- 


^■^^ 


m>y   r%  ^7^ 


1 


nouncing 
sion. 


profes- 


Here  is  the  famous  Fairbanks-Morse  Quartet  which  entertains  the  fans  regularly 
from  WEBW  at  Beloit,  Wis.  From  left  to  right:  Leland  Forman,  LeGrande  Warriner, 
Dave  McCullough  and  LeGrande  Brannen.  Dave  McCullough,  the  Scotchman  who  sings 
like  an  Irish  tenor,  sang  on  the  Radio  Age  program  from  KYW,  Saturday,   April  4. 


Not  a  Competi- 
tion 

"In  view  of  the 
unexpectedly  large 
amount  of  public 
interest  in  this 
question  of  who  is 
the  best  announc- 
er, I  should  like  to 
suggest  that  the 
Radio  Voice  Tech- 
nique Committee 
conduct  another 
and  more  compre- 
hensive rating  of 
the  announcers  of 
stations  in  and 
near  New  York 
City.  I  realize  that 
the  committee,  at 
its  recent  meeting, 
had  no  thought  of 
identifying  the 
holder  of  the 
highest  percentage 
as  the  "Best  An- 
nouncer" and  that 
the  findings  were 
of  a  purely  scien- 
tific nature." 


RADIO  AGE  for  May,  1925 


What  the  Broadcasters  are  Doinz 


The  demure  hat  shown  above  was 
one  of  the  "hits"  of  the  Millinery 
Show  broadcast  from  the  Copley- 
Plaza   Hotel   recently  by    WNAC. 


f[  Here  is  a  Station  That  Realizes 

That  Many  Listeners-in  Are  Women 

Radio  for  Milady 

at  WNAC 

The  First  Aerial  Millinery  Show  from 

This  Popular  Boston  Station  Results  in 

A  Flood  of  Letters  from  Devotees  of  Style 

By  OLIVER  JENKINS 


WOMAN  has  been  long  accorded  the  privilege  of  chang- 
ing her  mind  at  a  moment's  notice.  There  are  some 
people  of  the  opposite  sex  who  have  little  patience 
with  this  whimsical  trait  of  womankind,  asserting  that  it  is 
merely  a  convenient  refuge. 

It  goes  deeper  than  that,  however.  A  woman's  life  from 
beginning  to  end  has  a  great  deal  to  do  with  the  word,  "adapt- 
ability." She  must  be  ready  to  adapt  herself  to  all  sorts  of 
changes,  even  to  that  of  changing  her  name.  It  is  natural, 
therefore,  that  she  yields  easily  to  the  tyranny  of  that  most 
fickle  of  gods — the  God  of  Style. 

Perhaps  you  are  wondering  what  all  this  has  to  do  with 
radio.  Well,  Station  WNAC,  at  Boston,  claims  that  it  has 
a  lot  to  do  with  it.  And  Station  WNAC  ought  to  know  some- 
thing about  it,  for  this  station  was  the  pioneer  among  the 
radio  stations  in  the  Hub  of  the  universe. 

Long  ago  this  popular  Boston  station  decided  that  the 
woman  radio-fan  was  not  being  catered  to  as  was  fitting,  and 
plans  were  made  for  doing  something  along  this  line.  Miss 
Jean  Sargent,  whose  voice  is  familiar  to  every  New  England 
listener-in,  probably  about  a  year  ago  hit  upon  a  novel  idea. 
She  went  to  John  Shepard,  Jr.,  owner  of  the  station,  and 
outlined   the   scheme   sketchily. 

"Today,"  she  said,  "radio  stations  seem  to  have  the  belief 
that  they  must  present  programs  which  will  please  every 
variety  of  listener-in.  All  the  way  from  jazz  to  grand  opera 
must  *be  traveled  on  each  day's  program.  This  cannot  last. 
Sooner  or  later  stations  are  going  to  realize  that  specialization 
will  do  the  trick  much  better." 

Women  Have  Radio  Needs 

SHE  knew  that  there  were  many  women  becoming  interested 
in  radio.  Furthermore,  she  knew  that  graphic  descrip- 
tions of  boxing  bouts,  business  talks  and  stock  reports  con- 
tained little  interest  for  the  women  members  of  most  families. 
Something  ought  to  be  done  about  this. 

"Why  not  a  special  period  devoted  to  women  each1  day?" 
she  demanded. 

"And  what  could  you  put  into  that  period?"  was  the  ques- 
tion  asked   her. 

"Oh,  all  sorts  of  things.  Cooking  classes,  style  talks,  advice 
on  interior  decorating,  gardening — the  subjects  would  be 
endless." 

So  the  idea  was  tried  out  one  morning  over  the  radio.  The 
result  was  surprising.  Letters  poured  in  from  all  over  New 
England,  filled  with  praise  and  demanding  more  such  periods. 
It  was  too  popular  to  remain  cramped  in  an  hour's  period, 
however,  and  soon  several  hours  a  day  were  given  over  to  the 
women  fans.  Even  so,  the  station  was  handicapped  in  being 
able  to  cover  only  comparatively  small  territory  with  its 
100  watts;  imagine  the  joy  and  excitement,  then,  when  news 


was  received  last  December  that  WNAC  was  going  up  to 
500  watts. 

The  improvement  in  the  station's  power  now  makes  it 
possible  for  it  to  thoroughly  blanket  the  New  England  states. 

Programs  for  women  have  been  constantly  on  the  increase. 
Each  week  saw  a  more  elaborate  progress  in  this  direction. 
It  was  the  day  of  March  4  that  the  crowning  triumph  thus 
far  was  reached.  WNAC,  on  that  day  and  evening,  broad- 
cast for  the  first  time  in  radio  history,  a  real,  honest-to-goodness 
millinery  show.  The  latest  millinery  for  the  coming  Spring 
and  Summer  season  was  talked  over  at  length,  and  vivid 
descriptions  were  given.  All  of  the  finest  millinery  artists 
of  America  and  Europe  were  represented  at  this  greatest  of 
all    millinery    shows. 

All    the    Styles    by    Radio 

rT,HE  place  was  at  the  famous  Copley-Plaza  hotel,  and  in 
-*-  the  spacious  salon  during  the  afternoon  and  evening, 
more  than  two  thousand  of  the  best-known  hat  designers 
looked  over  the  models,  discussed  unusual  creations  and 
(Continued  on  Page  55) 


Here  is  one  of  those  latest  broad-brimmed  hats  which 

Miss   Jean   Sargent  described  from    the    style   show 

microphone  for  the  New  England  flappers. 


26 


RADIO  AGE  for  May,  1925 


Opening  a  new  broadcasting  station  is  a  rather  strenuous  feat.    The  pair  above,  Paul 

Johnson,   (seated.)   WCCO's  announcer,   and  Harry   Wilbur n,  station  manager,  were 

fagged  out  after  five  and  a  half  hours  of  steady  announcing.   In  fact,  Paul  insisted  that 

the  microphone  be  brought  to  him.      Wilburn  tried  to  oblige. 


WCCO — a  broadcasting  station 
with  a  purpose — that's  the  Gold 
Medal  Station,  Saint  Paul- Min- 
neapolis. Its  purpose  is  to  serve  the  North- 
west, and  twelve  hours  a  day,  seven  days 
a  week,  they  work  at  it  enthusiastically. 

Incidentally,  you  have  probably  noted 
their  earnest  endeavors  in  the  last  week  or 
two,  even  if  you  are  not  a  resident  of 
the  Northwest,  for  on  March  4  WCCO 
blossomed  out  with  its  new  5,000-Watt 
transmitting  equipment,  and  also  on  that 
evening  inaugurated  its  new  Minneapolis 
studios  on  top  of  the  Nicollet  Hotel. 
The  new  transmitter  is  one  of  the  super 
broadcasting  units,  and  the  Minneapolis 
studios  are  said  to  be  the  equal  both  in 
equipment  and  elegance  of  anything  in 
the  country. 

New  St.  Paul  Studios 

TVTOT  satisfied  with  this,  the  manage- 
J-  *  ment  of  WCCO  announced  that 
they  would  immediately  begin   building 


studios  in  Saint  Paul.  These  will  prob- 
ably have  the  most  unique  location  of 
any  studios  in  the  world,  for  they  will 
be  in  Saint  Paul's  handsome  new  Union 
Depot  used  by  nine  railroads. 

For,  you  must  remember,  the  Gold 
Medal  Station  represents  both  Saint  Paul 
and  Minneapolis.  It  is  not  the  toy  of 
any  group  or  class,  but  a  big  service  unit 
representing  two  large  cities  and  the  huge 
territory  which  they  serve. 

The  Gold  Medal  Station  is  also  unique 
in  the  manner  in  which  it  is  supported. 
The  physical  properties,  including  the 
transmitting  station  located  on  the  east 
bank  of  the  Mississippi,  18  miles  north- 
west of  Saint  Paul  and  Minneapolis, 
the  new  studios  on  top  of  the  Nicollet 
Hotel,  and  the  new  studios,  construction 
of  which  has  just  begun  in  Saint  Paul, 
are  all  the  property  of  the  Washburn 
Crosby  Company,  who  also  operate  the 
station  jointly  with  the  Saint  Paul 
Association    and    the    Minneapolis    Civic 


What  the  Broadcasters  are  Doing 

- ;.  \  How  Station  WCCO 

Super- 
ior the 
NORTH 

AS  TOLD  BY 


&  Commerce  Association.  A  brief  his- 
tory of  how  the  station  came  into  exist- 
ence is  as  follows: 

One  morning  late  in  July,  1924,  the 
Northwest  awoke  to  discover  that  it  was 
to  be  without  broadcasting  service.  This 
condition  was  brought  about  by  the  clos- 
ing of  the  Twin  City  Station  WLAG, 
operated  by  the  Cutting  &  Washington 
Radio  Corporation,  and  the  closing  of 
the  Dayton  Company's  Station,  WBAH. 

Everywhere  discussion  was  rife  as  to 
what  the  solution  of  the  problem  should 
be.  This  condition  continued  until 
August  5,  when  Washburn  Crosby  Com- 
pany submitted  a  proposal  to  the  Minnea- 
polis Civic  &  Commerce  Association  and 
the  Saint  Paul  Association.  This  pro- 
posal   was   as    follows: 

A  Co-operative  Plan 

WASHBURN  CROSBY  COMPANY 
offered  to  buy  the  physical  proper- 
ties of  WLAG  and  to  contribute  850,000 
a  year  towards  the  support  of  the  Twin 
City  Station  for  a  three-year  period, 
providing  the  business  men  of  Saint  Paul 
and  Minneapolis  together  would  con- 
tribute a  like  amount  for  the  same 
period.  The  station  was  to  be  known  as 
the  Gold  Medal  Station,  and  was  to  be 
credited  both  to  Saint  Paul  and  Minnea- 
polis. Washburn  Crosby  Company  also 
offered,  if  their  proposition  was  accep- 
ted, to  immediately  place  an  order  for 
a  new  5,000  watt  broadcasting  equip- 
ment to  take  the  place  of  the  old 
equipment. 

The  proposition  was  accepted,  and  on 
September  12  the  station  became  a 
reality.  Carrying  out  the  original  agree- 
ment, Washburn  Crosby  Company  placed 
an  order  for  one  of  the  new  5,000  watt 
broadcasting  sets,  which  was  designed 
especially   for   that   territory. 

On  March  4  the  new  broadcasting 
equipment  of  WCCO  was  formally  intro- 
duced to  the  public  when  it  broadcast  the 
inaugural  ceremonies  from  Washington 
by  remote  control. 

Wednesday  evening,  March  4,  WCCO 
opened  its  new  Minneapolis  studios  on 
top  of  the  Nicollet  Hotel  with  what  was 
unquestionably  one  of  the  finest  programs 
ever  broadcast  by  a  radio  station.  The 
program  opened  at  8:00  p.  m.,  with  a 
short  talk  by  Governor  Theodore  Chris- 
tianson  of  Minnesota,  in  which  he  out- 
lined the  value  of  radio  to  the  public. 
The  staff  of  the  station  was  then  intro- 


RADIO  AGE  for  May,   1925 

Is  Keeping  Up-to-Date 

Power 

Growing 

WEST       J 

E.  H.  GAMMONS 


duced  over  the  air.  At  8:30  began  a 
musical  program  which  continued  for 
five  hours.  Included  on  this  were  the 
leading  artists,  orchestras,  glee  clubs,  and 
quartets  of  the  Northwest,  the  band  .of 
the  famous  Third  Infantry,  oldest  regi- 
ment in  the  United  States  Army,  now 
stationed  at  Fort  Snelling. 

Invitations  were  sent  to  approximately 
5.000  residents  of  the  Twin  Cities  to 
attend  the  opening  and  view  the  broad- 
casts. The  result  was  a  tremendous 
crowd,  which  jammed  the  hotel,  ele- 
vators, hallways,  and  the  studios  them- 
selves all  evening,  and  gave  ample  evi- 
dence of  the  interest  which  Minneapolis 
and  Saint  Paul  have  in  radio. 

Towers  18  Miles  Away 

'  I  ''HE  transmitting  equipment  of  Station 
-*-  WCCO  is  located  18  miles  northwest 
of  the  Twin  Cities  on  the  east  bank  of  the 
Mississippi.    There  are  the  two  200-foot 


What  the  Broadcasters  are  Doing 


27 


aerial  towers  and  the  power  house. 
Programs  are  received  over  specially 
built  telephone  wires  from  studios  in 
Minneapolis  and  Saint   Paul. 


Visitors  at  the    Minneapolis    studios   of   WCCO  on    the  Nicollet  Hotel  may  view  the 

broadcasting  through  glass  panels,  as  shoicn  in  the  photograph.   Roominess  is  one  of  the 

outstanding  features  of  this  novel  station. 


Carlo 

'ischer, 

W  notedmu- 

'  sician    and 

f-  member       of 

Minneapolis  _ 

'  Symphony  Orches- 

JjP^  tra,  likes  broadcasting 

because  he  can  smoke  his 

cigarette  and  enjoy  playing. 

The  new  studios  on  top  of  the  Nicollet 
Hotel  are  housed  in  a  structure  built 
especially  for  them.  There  is  a  small 
studio  for  individuals  and  a  large  studio 
for  groups.  Between  them  are  the 
announcer's  and  operators'  rooms.  Glass 
panels  in  the  walls  of  the  studios  make 
possible  a  view  of  the  broadcasting  bv 
persons  in  the  reception  room  and  in  the 
promenade  along  one  side  of  the  large 
studio.  These  studios  are  literally 
"hung  in  the  air,"  the  ceilings  being  sus- 
pended, the  floors  built  upon  cork,  and 
the  walls  deadened  by  heavy  drapes 
which  are  adjustable.  They  are  luxuri- 
ously furnished  and  have  been  pro- 
nounced by  those  who  have  seen  practi- 
cally all  of  the  broadcasting  studios  as 
being  surpassed  by  none. 

With  "Service  to  the  Northwest"  as  its 
slogan,  the  Gold  Medal  Station  is  now 
ready  to  provide  the  Northwest  with 
programs   to   equal   any. 

New     Director     for     WCCO 

TTENRY  A.  BELLOWS,  well  known 
■*■■*-  magazine  editor  and  musical  critic 
of  the  Northwest,  will  become  associated 
with  WCCO  soon  as  director,  according 
to  an  announcement  made  by  the 
management. 

Mr.  Bellows  in  the  position  of  director 
will  have  complete  charge  of  the  arrange- 
ments for  and  all  the  broadcasts  from 
the   station. 

He  is  nationally  known  as  a  writer, 
editor  and  an  authority  on  music.  For 
thirteen  years  he  has  been  associated 
with  the  "Northwestern  Miller,"  Minne- 
apolis, as  managing  editor,  associate 
editor  and  director.  Prior  to  that  he 
was  editor  of  "The   Bellman." 


28 


RADIO  AGE  for  May,  1925 


What  the  Broadcasters  are  Doing 


The  West  Proclaims  a  Champion 


C' 'Uncle  John"  Daggett  of 

KHJ,  Los  Angeles,  is 

Contest  Winner 

for  March 

"For  East  is  East  and    West  is    West, 
And   Ne'er  the  twain  shall  meet." 

—  With  apologies  to  radio. 

RADIO,  the  great  annihilator  of 
distance,  has  reached  out  its 
mighty  arm  and  placed  its  finger 
on  a  spot  amid  the  orange  blossoms  and 
has  sought  out  the  Master  of  Ceremonies 
of  the  broadcasting  station  known  as 
KHJ,  at  Los  Angeles.  And,  meeting  on 
common  ground,  the  East  has  turned 
West  to  proclaim  a  new  champion  in  the 
person  of  our  beloved  "Uncle  John"  S. 
Daggett,  the  winner  of  RADIO  AGE'S 
popularity  contest  for  the  month  of 
March. 

A  newspaper  man  for  many  years, 
Uncle  John  has  long  since  learned  what 
constitute  the  fundamental  elements  of 
human  interest.  And  by  carrying  his 
unassumed  geniality  from  the  editorial 
offices  to  the  broadcasting  studio  of  the 
Los  Angeles  Times,  he  was  at  once 
accepted  as  one  of  the  foremost  announc- 
ers of  this  country.  For  he  is  anything 
but  supercilious. 

Step  into  the  studio  of  KHJ  and  you 
will  there  find  a  tall  man  with  sparkling, 
kindly  eyes,  rumpled  gray  hair  and  a 
winning  smile.  Look  into  his  heart  and 
you  will  discover  a  fatherly  personality 
that  radiates  through  the  microphone, 
bringing  cheer  to  the  sickroom,  the 
children,  the  house-wife  and  the  busi- 
ness man  alike.  Just  such  a  man  is 
Uncle  John. 

A  Suitable  Inspiration 

SURROUNDED  as  he  is  by  singing 
canaries,  the  studio  forms  a  fitting 
setting  from  which  to  gather  inspiration 
in  entertaining  the  little  folks.  In  this 
he  instantly  gained  popular  favor,  par- 
ticularly in  introducing  Queen  Titania, 
the  golden  haired  tot  of  the  "movies," 
and  the  Sandman,  O.  G.  Pirie,  her  father. 
This  trio  has  done  much  to  entertain 
and  at  the  same  time  teach  the  kiddies 
the  proper  way  of  living. 

For  John  Daggett  believes  that  the 
voice  of  radio  should  do  more  than  merely 
entertain.  Versatile  as  he  is  dynamic, 
he  feels  that  the  public  is  betrayed  if  a 


By  Harry  Aldine 


POPULARITY  CONTEST  COUPON 

Harry  Aldine.  Contest  Editor 

RADIO  AGE,  500  N.  Dearborn  St.,  Chicago. 

I  wish  to  east  my  vote  for: 

Name  of  favorite 

Classification 

Station. Date  Heard 

Name  (optional]— 

Address  [optional] 


Here  is  "Uncle  John"  himself,  the  beloved 
friend  of  the  grownups  and  children  at  the 
station  of  "Kindness,  Happiness  and  Joy," 
where  the  orange  blossoms  come  from. 

performer  is  not  inspiring  to  better  things 
of  life  and  likewise  educational.  The 
entertainment  must  be  wholesome,  and 
above  all  it  should  appeal  to  the  masses. 
Religion  is  given  its  place  in  the 
schedule  of  KHJ,  and  here,  too,  Uncle 
John  has  shown  his  keen  understanding 
by  offering  the  microphone  to  all  sects 
and  denominations. 

In  observing  the  spirit  of  close  harmony 
ever  prevailing  between  the  director  and 
his  many  artists,  one  at  once  understands 
why  Uncle  John  has  little  difficulty  in 
securing  real  talent  for  the  delight  of 
his  many  listeners.  Despite  his  portrayal 
of  diligence  itself,  he  always  has  time  for  a 
pleasant  sally  or  kind  remark  for  all  who 
come  in  contact  with  him.  The  studio 
houses  one  large  "happy  family." 

And  the  radio  artists  are  not  the  only 
ones  present.  John  Daggett  extends  the 
hand  of  cordiality  to  all  visitors  to  the 
capacity  of  his  studio. 
Those  of  his  vast 
audience  who  desire 
a  "close-up"  of  what 
happens  behind  the 
scenes  are  assured  a 
genuine  treat  of  true 
western  hospitality. 
KHJ,  the  visitor 
is  told,  means  Kind- 
ness, Happiness  and 
Joy,  and  if  you  have 
not  already  been  con- 
vinced,  just    give 


{[Intensive  Campaign  May- 
Upset  Popularity 
Leaders  at  Any 
Moment 

your  dials  a  twirl  some  night  to  the 
405  meter  wave  and  stand  by  to  be 
washed  overboard  by  the  joyful,  "KHJ, 
Los  Angeles,  California." 

THE   WINNER   FOR   MARCH 
John  S.  Daggett  ....Announcer KHJ,  Los  Angeles 

WINNERS    OF  PRECEDING  MONTHS 

July Duncan    Sisters,    KYW 

August Bill  Hay,  KFKX 

September Karl  Bonawitz,   WIP 

October _ H.  W.  Arlin,  KDKA 

November Bert  Davis,  WQJ 

December Jack  Nelson,  WJJD 

January Art  Linick,  KYW 

February Coon-Sanders  Orchestra,   KYW 

STANDING  TO  MARCH  15 
Name   and   Classification  Where  Heard 

Karl    Bonawitz,    Organist WIP,    Philadelphia 

Bill   Hay,   Announcer. KFKX,    Hastings 

H.  W.  Arlin,  Announcer KDKA,  Pittsburgh 

Coon-Sanders'  Nighthawks,  Orchestra,  KYW,  Chi. 

Harry   M.   Snodgrass,   Entertainer 

WOS,  Jefferson  City 

Jack    Nelson,    Announcer WJJD,    Mooseheart 

Bert  Davis,  Entertainer WQJ,  Chicago 

John  S.  Daggett,  Announcer KHJ,  Los  Angeles 

Art    Linick,    Entertainer KYW,    Chicago 

Ford  &  Glenn,  Entertainers WLS,  Chicago 

Duncan    Sisters,    Entertainers KYW,    Chicago 

Lambdin     Kay,     Announcer. WSB,     Atlanta 

J.    Remington   Welsch,    Organist-. KYW,    Chicago 

Fred  Smith,  Announcer WLW,  Cincinnati 

E.    L.    Tyson,    Announcer WWJ,    Detroit 

Hired   Hand,    Announcer WBAP,    Fort   Worth 

"Sen"      Kaney,      Announcer ..KYW,      Chicago 

Nick  B.  Harris,  Entertainer.. ..KFI,  Los  Angeles 
Jerry  Sullivan,  Announcer-Entertainer,  WQJ,  Chi. 

Edward    H.    Smith,    Director-Player... 

WGY,  Schenectady 

Charles  E.   Erbstein,   Announcer WTAS,   Elgin 

Lee  Sims,  Pianist KYW,  Chicago 

Wendell  Hall,  Entertainer WDAF,  Kansas  City 

Howard   Milholland,    Announcer.. ..KGO,    Oakland 

Scottish    Rite    Orchestra KGO,    Oakland 

Banks  Kennedy,  Entertainer ...WEBH,  Chicago 

S.    Hastings,    Announcer KFI,    Los   Angeles 

Robert  Boniel,  Announcer... WEBH,  Chicago 

Arion  Trio,  Instrumental KGO,  Oakland 

Deadline  Is  Near 

THE  contest  is  rapidly  drawing  to  a 
close.  At  midnight,  June  15,  RADIO 
AGE  will  accept  the  last  of  the  ballots 
cast  for  the  many  favorites  in  the  Popu- 
larity Contest. 

During  the  period  from  February  16  to 
March  15,  John  Daggett  by  virtue  of 
having  garnered  the  greatest  number  of 
votes  through  the  thirty  days,  advanced 
his  position  from  twelfth  to  eighth  place. 
It  will  also  be  noted  that  H.  W.  Arlin, 
Harry  Snodgrass,  Jack  Nelson,  Fred 
Smith  and  "Sen"  Kaney  have  all  strength- 
ened their  positions  in  "Standing  to 
March  15."  Charles  Erbstein,  Lee  Sims 
and  Arion  Trio  are  newcomers  to  the 
list. 

Up  to  now,  the  candidates  at  the  head 
of  the  list  have  been  fairly  consistent  in 
their  leadership,  but  in  spite  of  the  short 
time  that  the  contest  has  yet  to  run, 
victory  is  by  no  means  assured  to  any 
one  of  them.  Many  a  race  is  won  or  lost  by 
clever  jockeying   near  the    finish. 

So  now  for  the  smashing  drive!  Your 
opportunities  to  say  it  with  ballots  for 
your  favorite  are  limited.  Clip  the 
coupon  and  send  it  in  now  while  the  con- 
test is. fresh  in  your  mind. 


RADIO  AGE  for  May,  1925 


What  the  Broadcasters  are  Doing 


29 


Ford  and  Glenn  discovered  that  fact,  and 


Common  Sense 

Replaces  Nursery 

Rhyme  Methods 


THE  BEDTIME  story  is  coming  into 
its  own.  Not  so  very  long  ago  the 
"queer"  ladies  and  gentlemen  who 
furnished  the  entertainment  for  the  kid- 
dies by  radio  had  quite  a  hard  time  get- 
ting the  radio  public  to  take  them  serious- 
ly. In  fact,  they  had  a  hard  time  taking 
themselves  seriously,  and  as  a  result  the 
great  American  sport  of  radio  bedtime 
story-telling  failed  to  rise  above  the  level 
of  crude  humorfor  several  monthsafter  the 
popular  advent  of  the  broadcasting  art. 
The  originators  of  the  bedtime  story 
idea  thought  that  to  amuse  the  kiddies 
they  had  to  adhere  strictly  to  nursery 
rhyme  psychology.  They  never  thought 
for  a  moment  that  maybe  their  childish 
listeners  could  rise  above  the  moron  plane 
and  enjoy  some  real  common-sense  Chil- 
dren's Hours. 

The  entrance  of  a  new  form  of  Bedtime 
Story  material  occurred  almost  simultan- 
eously in  Boston  and  Chicago.  The 
owners  of  Station  WEEI  in  Boston  de- 
cided to  form  a  "Big  Brother"  Club  along 
the  lines  of  the  well-known  organization 
of  that  name,  and  to  appeal  to  boys  and 
girls  of  all  ages  by  the  radio.  No  silly 
Bedtime  Stories,  mind  you;  no  childish 
prattle  on  how  this  little  brown  bear 
came  home  with  his  folks  and  found  his 
meal  absorbed  by  an  unknown  mouth. 
The  Big  Brothers  of  radio  set  out  to  do 
some  real  work  among  the  children,  and 
to  substitute  this  brotherhood  movement 
for  the  meaningless  kindergarten  material 
that  persisted  in  remaining  part  and 
parcel  of  every  radio  station. 

7000  Child-Members 

WEEI'S  idea  was  an  immediate  suc- 
cess.   In  a  little  over  a  year  member- 
ship in  the  Big  Brother  Club  has  jumped 


"Uncle  Bob"  (Walter  Wilson)  of  KYW, 

who  is  known  to  millions  of  children  who 

listen  to  him  every  night  at  Bedtime  Story 

Hour. 

to  7000  child  members,  ranging  from  1  to 
14  years.  "Bob"  Emery  and  Dorothy 
Blackwell  are  the  guiding  lights  of  this 
juvenile  institution,  and  it  is  through 
their  efforts  that  the  Big  Brother  Club  is 
today  one  of  the  strongest  children's 
organizations  in  the  country. 

While  all  this  was  going  on  in  the  East, 
Walter  Wilson,  the  original  bedtime  story 
man  known  as  "Uncle  Bob"  from  KYW, 
Chicago,  was  changing  his  mode  of  "ap- 
proach"  also. 

Uncle  Bob  had  been  with  radio  from 
the  start,  and  he  had  tried  every  known 
means  of  gaining  the  favor  of  the  kiddies. 
Of  course,  his  nursery  rhyme  method  was 
successful,  for  he  had  the  knack  of  con- 
veying his  personality  from  the  studio  to 
the  children  listening  in,  but  like  the  few 
keen-minded  radiologists  of  two  years 
ago,  Wilson  realized  the  children  must 
have  something  better  or  they  would  soon 
outgrow  his  daily  Bedtime  Story  Hour. 

So  Uncle  Bob  formulated  a  standard 
Children's  Hour  program  that  not  only 
interested  all  children — everywhere —  but 
their  parents  as  well!  His  method  today 
consists  largely  of  singing  and  playing 
the  piano,  intermingling  modernized 
children's  songs  with  the  well  known 
popular  melodies.  And  this  new  method 
has  been  so  successful  that  KYW's  bed- 
time story  listeners  have  doubled  during 
the  past  year. 


today  their  popularity  is  tremendous.     Above  is  shown   Tiny  Violet  Sileo  lisping 
into  the  WLS  microphone  for  admiring  youngsters.     At  the  left,  Dorothy  Blackwell 
of  WEEI,  Boston,   is  introducing  a  new  "pal"  to  the 
7,000  members  of  the  "Big  Brothers'  "Club- 

A  New  Kind 

of 

Bedtime 

Story 

By  RUSSELL  H.  HOPKINS 

"Uncle  Bob"  Wilson  believes  in  per- 
sonal contact,  and  his  immense  popu- 
larity can  be  largely  attributed  to  his 
making  periodic  "personal"  appearances 
in  towns  where  his  Bedtime  Hours  are 
most  popular.  Both  Wilson  and  KYW 
realize  that  this  is  an  invaluable  aid  in 
holding  the  station's  young  friends. 

Children  Help,  Too 

T^ORD  RUSH  and  Glenn  Rowell,  the 
-*-  Bedtime  Story  Boys  of  WLS,  Chicago, 
get  closest  to  the  children's  hearts  by 
introducing  the  policy  of  having  children 
do  broadcasting  during  "Lullaby  Hour" 
from  WLS.  On  certain  days  of  the  week 
Ford  and  Glenn  invite  ambitious  Lullaby 
Listeners  to  participate  in  their  intimate 
talks  with  the  radio  listeners,  and  as  a 
result,  thousands  of  children  who  are 
WLS  "fans"  are  competing  among  them- 
selves to  be  chosen  to  help  "Big  Ford  and 
Little  Glenn."  The  popularity  of  their 
Lullaby  Club  has  resulted  in  a  tide  of 
correspondence  that  nearly  equals  that 
received  from  all  other  programs  com- 
bined. 

And  Ford  and  Glenn  abo..shed  story- 
telling long  ago.  Instead,  they  talk  to 
each  other  in  a  personal  way  and  talk  to 
the  kiddies  as  if  they  were  in  the  same 
room. 

Truly,  this  is  an  era  of  new  things  in 
radio  and  espaciallv  in  the  gentle  art  of 
winning  juvenile  listeners  and  holding 
them  as  they  grow  older. 

(Copyright,  1926.  By  Radio  Age,  Inc.) 


30  RADIO  AGE  for  May,  1925 


What  the  Broadcasters  are  Doins. 


Some  Radio  Programs  and  Personalities 

Behind  the  Scenes  |—™-  -  :  i 

at  KFI  m^       ' 


Where  Broadcasting  Is  an  "Art" 
By  MARGOT  LYON 

Program  Director,  KFI, 
Los  Angeles,  Cal. 


THE  phonograph  and  the  camera 
introduced  the  surprising  fact  to 
many  people  that  other  people 
did  not  see  and  hear  them  as  they  saw 
and  heard  themselves.  The  latest 
development  of  science  in  disillusioning 
some  and  enchanting  others  is  the 
radio.  As  has  been  often  said  of  other 
things,  you  never  can  tell  who's  who 
over  the  radio  until  you  have  heard 
them  over  the  radio. 
.  Many  of  KFI's  artists  have  sung  but 
rarely  elsewhere,  some  of  them  coming 
to  KFI  with  friends  just  to  see  what 
went  on  behind  the  scenes,  and,  singing 
just  once  at  the  request  of  same  of  the 
regular  artists,  have  made  such  a  suc- 
cess that  they  have  come  again  and 
again. 

It  is  peculiar  to  witness  the  reaction 
of  those  who  hear  singers  in  the  studio 
and  then  walk  out  to  the  loud  speaker 
and  hear  the  same  voice  as  it  comes 
off  the  air.  A  tenor  whose  voice  in  the 
studio  seems  to  lack  resonance  and 
purity  will  broadcast  with  the  utmost 
clarity  and  sweetness,  his  broadcast 
voice  leaving  nothing  to  be  desired, 
whereas  a  trained  voice,  that  from  the 
concert  stage  has  delighted  thousands, 
will    not    "radiate"    well    at    all. 

It's  Not  a  "Cinch" 

T^UE  to  the  difficulty  in  judging 
■'—'  a  good  radio  voice  and  to  other 
reasons  not  so  easy  to  illustrate,  the 
position  of  a  program  director  is  no 
sinecure.  However,  the  vast  KFI  audi- 
ence seems  to  be  pleased  with  the  sta- 
tion's efforts,  to  judge  by  the  many 
letters  they  send. 

The  demand  of  radio  broadcasting 
has  developed  a  supply  of  radio  enter- 
tainers. The  field  of  broadcast  enter- 
tainment is  being  widened  by  the  sincere 
efforts  of  the  studio  managers  and  the 
artists. 

As  in  the  early  days  of  vaudeville, 
the  first  effort  toward  entertainment 
has  been  the  attempt  to  present  novelties 
and  unusual  stunts.  However,  more 
and  more  over  the  radio,  as  over  the 
footlights,  the  combined  effort  of  artist 
and  station  has  developed  a  sincere  and 
worth-while  form  of  entertainment  emi- 
nently   fitted    for    the    needs    of    radio. 


The  audience,  lis- 
tening   with    head- 
phones or  with  loud 
speaker,     are    blind 
as  far  as  the  studio 
and  what  is  broad- 
cast from  the  studio 
are    concerned. 
Every    program 
must     be      planned 
from    the    start    as 
though  it  were  being 
played    before    a 
theater     with     the 
lights  off.  Although 
this   may  seem  self- 
evident    it     is    not 
generally    con- 
sidered.  Every  trick 
of  the  human  voice, 
every    intonation, 
inflection  and  artic- 
ulation must  be  polished  to  the  last  point 
before     the     audience     can     attain     the 
maximum  enjoyment  from  the  program. 
By  letters  and  by  broadcast  requests 
for     information,     KFI     has     made     up 
charts    of    the    type    of    program    most 
enjoyed    by    the    public    and    finds    that 
almost    every    kind    of   program    has   its 
adherents.       For    the    humorous    mono- 
logue   to    the     classic    string    quartette 
come    letters    from    isolated    farms    and 
from  yachts  and  country  estates.   Strange 
to  say,  the  letter  in  favor  of  the  string 
quartette   is    more   than   likely   to   come 
from  the  tired  wife  of  the  farmer,   who 
washes    dishes    or    irons    her    clothes    a 
thousand    miles   away   from    KFI,   while 
listening  to   Mozart  or   Haydn. 

Letters  come  in  from  the  blind  whose 
only  comfort  is  the  radio  and  from  the 
deaf  who  perhaps  have  never  heard  a 
sound  from  the  great  silent  world  until 
with  ear-phones  they  have  picked  up  a 
program  from  KFI. 

Phone  Lines  Always  Busy 

ONE  of  the  most  interesting  things 
to  be  met  with  in  the  broadcasting 
station  is  the  number  of  telephone 
calls  that  come  in  during  the  various 
programs,     ranging     from     requests     for 


Frank  Oliver,  a  traveling  radio  dramatist,  is  one  of  those  rare 
artists  who  believe  that  they  must  dress  and  act  the  personality 
they  seek  to  portray  in  the  studio  itself,  if  they  hope  to  convey 
that  same  personality  to  the  listener,  who  can  only  "visualize" 
through  his  ears. 


Somewhat  peculiar  are  the  requests 
for  songs.  A  singer  may  just  have 
finished  "Pace  pace  mio  dio"  when  an 
ingratiating  voice  will  ask,  over  the 
phone  of  course,  if  the  lady  who  just 
sang  could  please  render  "Charley,  My 
Boy." 

Sometimes  there  is  a  fereat  deal  of 
pathos  in  the  requests.  One  particular 
night  a  frantic  mother  called  asking 
if  we  could  not  in  some  way  help  her  to 
locate  her  little  boy  who  had  strayed 
away.  It  had  to  be  explained  to  her 
that  the  laws  of  broadcasting  did  not 
permit  such  announcements  to  be  made. 
Other  times  an  old  time  number  will  be 
asked  for,  to  please  some  one  who  is 
ill  or  shut  in.  Then  the  artists  will 
scurry  about  and  among  themselves 
refresh  their  memories  and  the  most 
daring  of  them  will  attempt  to  "fake" 
a  piano  accompaniment. 

It  is  not  possible  to  grant  all  the  re- 
quests asked  for  during  the  actual 
broadcasting  hour,  and  it  is  the  habit 
of  KFI  at  certain  times  to  ask  those 
who  wish  to  hear  their  favorites  sing 
certain  numbers  to  be  sure  to  write  in 
their  requests  so  that  the  artists  may 
plan  on  pleasing  their  friends.  When 
the  fact  is  known  that  as  many  as  thirty 
various  numbers  to  inquiries  as  to  the  requests  have  been  phoned  in  during 
proper  feeding  of  a  baby  and  what  are  one  hour  for  one  artist,  such  as  Starr 
the  ten  points  of  a  prize  winning  Airedale.  (Continued  on  page  54) 


RADIO  AGE  for  May,   1925 


The  Magazine  of  the  Hour  31 


A  Compact  Traveling  Set 

The  6-Tube  "Portatron" 


By  JOHN  B.  RATHBUN 


G 


OMPACT  portable  radio  receivers, 


Copyright:    1925 


having  sufficient  power  to  operate 

an 
fo 


Controls  are  Simple 


desirable   for   home   use    as   well    as   lor  i     y-\  .  *-\    '   . 

camping  and  motoring  trips.      Provided     dflU      UperatlOn      i^tliet 

with  self-contained  batteries,  such  outfits     ! 


can  be  easily  moved  about  from  room  to 
room  in  the  house  or  can'be  carried  to  the 
home  of  a  friend  to  provide  music  for  a 
dance  or  for  other  similar  occasions. "The 
portable  has  a  much  wider  field  of  appli- 
cation than  the  conventional,  cumber- 
some cabinet  with  external  batteries,  and 
should  be  seriously  considered  by  those 
who  desire  a  receiver  of  the  all-round  type. 

For  the  sake  of  simplicity,  such  an 
outfit  should  be  of  the  single  control  type, 
or  should  not  have  more  than  two  controls 
at  the  most.  It  should  have  at  least  two 
radio  frequency  stages  for  distance  and 
for  operation  on  a  loop  aerial,  and  at 
least  two  audio  frequency  stages  for  loud 
speaker  operation..  With  transformer 
coupling  this  means  at  least  five  tubes, 
if  the  tubes  are  not  reflexed,  and  we  must 
therefore  carefully  consider  the  methods 
of  coupling  the  stages  to  conserve  space 
and  to  minimize  the  number  of  controls. 

Dry  batteries  must  be  used  for  the'fila- 
ment  "A"  battery,  and  the  type  of  tube 
must  be  such  that  not  more  than  three 
or  four  Xo.  6  dry  cells  will  be  required. 
This,  of  course,  suggests  the  "199"  tube, 
which  is  ideal  for  a  portable  rig  because  of 
its  low  filament  current  consumption. and 
small  size.  Five  "199"  tubes  will  take 
5  x  0.06  =0.30  ampere  which  is  not  pro- 
hibitive for  dry  cell  service,  and  the  cells 
will  last  for  a  considerable  length  of  time 
on  such  work.  Six  tubes  will  take:  6x0.06 
=  0.36   ampere   which    is    within  reason. 

Transformer  coupling  between  either 
the  radio  frequency  or  audio  frequency 
stages  takes  up  considerable  room.  If 
the  R.  F.  transformers  are  of  the  "tuned" 
type  then  they  must  be  spaced  well  apart 
to  prevent  coupling  back  between  stages, 


and  this  system  must  therefore  be  dis- 
carded right  at  this  point,  both  for  the 
reason  that  it  takes  up  much  room,  and 
also  for  the  reason  that  a  separate  dial 
control  will  be  required  for  each  radio 
stage  (and  for  the  tuner  unit  in  addition) 
which  will  bring  the  total  number  of 
controls  up  to  three  or  more.  This  is  out 
of  the  question  in  a  portable  outfit;  hence 
we  must  look  farther  for  a  means  of  radio 
frequency  stage  coupling.  We  should 
have  only  a  single  selective  control  for  the 
tuner  unit,  and  no  variable  controls  after 
the  first  stage  that  are  represented  by 
dials  or  knobs  on  the  front  of  the  panel. 

Resistance  Coupling 

Resistance     coupling     for     the      radio 
frequency    and    audio    frequency     coup- 


THE  RECEIVER  FOR 
YOUR  NEEDS 

This  Summer's  tendency  will  be 
for  simplified  radio  receivers,  with 
compact  parts  and  ease  of  operat- 
ion and  control.  A  radio,  set 
without  these  characteristics  can- 
not be  called  up-to-date. 

THE  RADIO  AGE  ANNUAL  for 
1925  contains  several  of  these  won- 
der hookups  that  are  easy  to  build, 
easy  to  operate  and  pleasant  to 
hear.  The  latest  in  portable  sets  as 
well  as  the  larger  models  are  all  in 
this  new  ANNUAL,  which  is  yours 
for  $1.  Send  your  remittance  now 
if  you  want  to  have  this  radio 
handbook  with  you  on  your  vaca- 
tion this  year  as  an  ever-ready 
radio  guide. 

$1  while  they  last. 


Blueprints  of  the  Six-Tube  "Porta tron"  on  Two 


ling  requires  no  separate  interstage  con- 
trols, but  unfortunately,  resistance  coup- 
ling in  the  radio  frequency  stages  is  only 
efficient  on  long  wavelengths,  say  on 
wavelengths  above  1,000  meters.  This 
resistance  coupling  method  will  be  fine 
for  the  audio  stages,  and  is  just  w*hat  will 
be  used  for  the  output,  but  we  will  have 
to  guess  again  in  regard  to  the  coupling 
on  the  R.  F.  end  of  the  hookup.  The 
untuned  or  fixed  radio  frequency  trans- 
former at  once  suggests  itself,  but  for  this 
time  it  must  be  rejected  because  of  the 
space  occupied  and  for  the  reason  that 
such  transformers  are  likely  to  "back- 
couple"  between  stages  if  crowded  to 
gether  as  closely  as  we  intend  to  crowd  the 
stages  of  this  outfit. 
*-\ 

'  I  ''HERE's  only  one  other  coupling  pos- 
-■-  sible  on  the  R.  F.  end,  and  that  is 
by  means  of  inductances  of  the  "choke 
coil"  order,  which  are  connected  into  cir- 
cuit just  like  the  resistance  units  of  a 
resistance  coupled  stages.  One  end  of 
the  choke  coil  is  connected  to  the  plate  of 
the  tube,  while  the  other  end  goes  to  the 
(+B).  The  connection  between  the 
first  tube  plate  and  the  grid  of  the  follow- 
ing tube  is  made  through  a  fixed  condenser 
just  as  in  the  case  of  the  resistance 
coupling  scheme.  The  choke  coils  must 
have  a  very  much  higher  inductance  than 
commonly  used  with  radio  frequency 
tuning  units.  They  should  consist  of 
several  thousand  turns  of  very  fine  wire. 
The  secondary  coil  of  an- audio  frequency 
transformer  will  be  just  about  right  for 
this  purpose  when  standard  100  Milli- 
henry chokes  cannot  be  obtained.  The 
inductive  value  must  be  sufficient  to  choke 
back  the  high  frequency  plate  current  so 
that  it  will  not  short  circuit'back  through 
the  "B"  battery  connections,  and  at  the 
same  time  the  coil  resistance  should  not 
be  sufficient  to  interfere  with  the  supply 

(Turn  to  page  34) 
Pages  Following 


34 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


( Continued  from  page  31) 
of  continuous  "B"  battery  current  to  the 
plate  of  the  tube.    The  choke  coil  permits 
the  "B"  battery  current  to  pass  to  the 
plate,  but  chokes  back  the  R.  F.  current. 

Radio  Frequency  Amplification 

rr,HE  application  of  the  choke  system 
•"-  to  the  first  three  tubes  will  be  seen 
in  Fig.  1  and  Fig.  2,  where  Fig.  1  is  a 
schematic  diagram  using  symbols,  and 
Fig.  2  is  a  picture  wiring  diagram.  The 
first  will  be  of  more  service  to  the  experi- 
enced builder  in  "doping  out"  the  circuit, 
while  the  latter  will  show  the  novice  how 
the  wiring  connections  are  actually  made 
to  the  parts.  Fig.  3  is  a  front  elevation 
of  the  panel  and  cabinet,  while  Fig.  4  is  a 
rear  elevation  showing  the  parts  assem- 
bled at  the  rear  of  the  panel.  Fig.  3A  is 
a  sectional  view  as  seen  from  one  side  of 
the  assemblage. 

Taking  Figs.  1-2,  we  see  that  an  aperi- 
odic type  coupler  is  used  at  (L1-L2) 
which  is  tuned  by  vernier  variable  coiIt 
denser  (CI)  connected  across  the  second- 
ary coil  (L2)  of  the  coupler.  This  can  be 
a  home-made  coupler  such  as  has  been 
described  many  times  in  these  columns; 
it  can  be  a  standard  neutrodyne  trans- 
former or  else  a  standard  adjustable 
aperiodic  tuner.  In  any  event,  the 
primary  coil,  (LI)  is  untuned.  When  the 
usual  flat  top  aerial  is  used,  the  aerial 
lead-in  wire  is  connected  to  (ANT)  and 
the  ground  wire  at  (GND),  a  system  whch 
gives  the  greatest  range  and  signal 
strength.  By  connecting  the  ends  of  a 
loop  aerial  at  (XI)  and  (GND),  and  then 
opening  the  grid,  switch  (T),  we  can  oper- 
ate on  the  loop  aerial.  The  tap  switch 
(T)  cuts  out  the  secondary  coil  (L2) 
which  is  necessary  on  loop  reception. 
Coil  (L3)  suppresses  oscilations. 

When  operating  on  the  flat  top  aerial, 
or  a  type  similar  to  the  usual  outdoor 
aerial,  the  coupling  between  the  primary 
(LI)  and  the  secondary  (L2)  must  be  very 
"loose;"  that  is,  there  must  be  a  consider- 
able space  between  the  two  coils.  For  this 
reason,  it  is  best  to  adopt  a  ready-made 
coupler  in  which  the  coupling  gap  can  be 
easily  adjusted  until  the  proper  degree  is 
found  by  experiment.  We  have  only  one 
control,  and  to  obtain  the  proper  selec- 
tivity in  local  jams  we  must  have  the 
proper  "looseness"  between  the  coils.  The 
home-made  coil  generally  contains  from 
12  to  15  turns  of  No.  26  D.  S.  C.  wire  on 
the  primary  (LI),  and  from  55  to  60  turns 
on  the  secondary  coil  (L2),  using  the  same 
size  wire.  The  distance  between  the  two 
coils,  or  the  coupling,  may  be  from  fls  to 
%  inch  or  even  greater. 

By  using  a  4.5  volt  three  cell  "C"  bat- 
tery at  (C),.  we  usually  get  greater  sensi- 
tivity and  signal  strength,  and  the  battery 
also  reduces  the  tendency  towards  free 
oscillations  in  the  circuit.  However,  the 
"C"  battery  can  be  omitted  in  many 
cases  without  serious  loss.  The  switch 
(T)  can  be  the  usual  form  of  tap  switch 
with  one  active  contact  point,  and  one 
dead  contact. 

The  first  radio  frequency  tube  (Tl), 
which  follows  the  tuning  inductance,  is 
provided  with  the  choke  coil  (CC)  con- 
nected to  the  plate  at  one  end  and  to  the 
(4-B)  line  at  the  other,  so  that  from  90 


to  135  volts  of  "B"  battery  will  be  main- 
tained on  the  plate.  The  plate  of  tube 
(Tl)  is  coupled  to  the  grid  of  the  second 
R.  F.  tube  (T2)  through  the  fixed  coup- 
ling condenser  (Kl)  which  is  ordinarily 
of  0.002  mf.  capacity.  This  condenser 
prevents  the  application  of  the  plate 
voltage  to  the  grid  of  (T2)  and  thus  pre- 
vents the  high  "B"  voltage  from  paralyz- 
ing this  tube.  The  choke  coil  (CC)  can 
be  the  secondary  winding  of  an  audio 
transformer,  and  as  will  be  seen,  prevents 
the  R.  F.  plate  output  from  short  circuit- 


YOU  PORTABLE  FANS! 

If  you  want  a  smaller  and  even 
more  compact  portable  receiver 
than  is  described  in  the  RADIO 
AGE  Blueprint  section  this 
month,  you'll  find  another  in 
the  JUNE  ISSUE,  out  May  15. 
It  will  be 

A  3 -TUBE  PORTABLE 

REFLEX 

"THE  BABY  OF  THEM 

ALL." 

Just  the  thing  to  put  in  your 
suitcase  for  that  vacation  trip. 
By  John  B.  Rathbun 

IN  JUNE  RADIO  AGE 


ing  through  the  "B"  batterj-.  It  allows 
the  "B"  battery  to  go  to  the  plate  of  the 
first  tube,  however,  but  stops  the  high 
frequency  current  from  backing  out. 
This  requires  no  control. 

Filament  Controls 

\  LL  of  the  amplifying  tubes,  five  in 
J-~*-  number,  are  provided  with  auto- 
matic filament  controls  which  maintain 
the  amplifying  tube  current  at  the  proper 
intensity  without  rheostats  or  other 
manual  controls.  This  is  a  decided  step 
toward  simplicity  and  compactness,  and 
prolongs  the  life  of  thetubes  by  holdingthe 
filaments  constantly  at  the  proper  temper- 
ature. A  manual  rheostat  (R)  of  the 
usual  form  must  be  provided  for  the 
detector  tube  (T3)  as  this  has  a  rather 
critical  filament  adjustment  that  cannot 
be  automically  controlled.  The  rheostat 
(R)isrepresentedonthefront  of  the  panel 
by  a  knob  as  shown  by  Fig.  3,  and  is  the 
only  control  outside  of  the  condenser  dial 
(CI).  A  switch  (SW)  must  be  provided  for 
shutting  off  the  filament  current  when  the 
set  is  not  in  use.  It  is  no  longer  possible  to 
turn  off  the  amplifying  tubes  indepen- 
dently as  when  the  usual  form  of  rheostat 
is  used.  This  can  be  an  ordinary  battery 
switch  of  the  type  to  be  found  at  any 
radio  store. 

A  second  choke  coil  (CC)  is  shown  con- 
nected to  the  plate  circuit  of  the  second 
radio  tube  (T2),  and  as  this  is  exactly 
similar  to  the  first,  there  will  be  no  further 
comment.  The  output  of  tube  (T2)  leads 
to  the  detector  tube  through  the  0.00025 
mf.  grid  condenser  (K2).  It  should  be 
noted  that  a  one  megohm  grid  leak  (V), 
shown  dotted  on  the  grid  of  tube  (T2), 
will  often  prove  of  advantage.  It  should  at 
least  be  tried  outin  the  position  indicated 
by  the  dotted  lines  before  completing  the 
set,   for  it  sometimes  stabilizes  the  first 


tubes  and  increases  their  effectiveness. 
At  tube  (T3)  we  have  the  detector  tube 
which  is  connected  into  circuit  by  the 
0.00025  mf.  fixed  grid  condenser  (K2),  and 
the  one  megohm  grid  leak  (GL1).  As  with 
all  the  other  tubes,  this  is  a  "199"  tube, 
but  to  prevent  critical  rheostat  adjust- 
ments the  plate  is  supplied  with  45  volts 
by  an  intermediate  tap  at  the  "B"  bat- 
tery. From  the  detector  tube  on,  all  of  the 
stages  are  resistance  coupled  by  the 
50,000  ohm  resistances  (M1-M2-M3)  and 
the  grid  leaks  (GL2-GL3-GL4).  The 
hand  controlled  rheostat  is  shown  at  (R) 
by  which  the  detector  filament  can  be 
controlled  accurately  for  any  conditions. 
For  use  with  "199"  tubes,  the  resistance 
of  (R)  should  be  from  30  to  40  ohms,  the 
former  for  dry  cell  operation  and  the 
latter  for  use  with  storage  cells. 

Resistance  Coupled  Audio 

\  LL  of  the  three  audio  frequency  tubes 
-'*-  (T4-T5-T6)  are  supplied  with  the 
full  "B"  battery  voltage  through  the 
fixed  resistances  (M1-M2-M3)  which  have 
a  resistance  of  50,000  ohms.  The  plates 
and  grids  of  the  tubes  are  connected  by 
means  of  the  fixed  condensers  (K3-K4- 
K5)  of  0.005  mf.  capacity.  This  value 
is  not  critical,  and  0.006  mf.  fixed  con- 
densers can  also  be  used  if  this  is  the  only 
capacity  to  be  found  in  stock  at  your 
radio  store.  They  must  be  of  the  mica 
dielectric  type,  or  condensers  in  which  the 
plates  are  separated  by  thin  sheets  of 
mica  insulation. 

The  grid  leaks  (GL2,  GL3,  GL4) 
of  the  audio  tubes  "taper"  toward  the 
rear;  that  is,  the  last  tube  has  a  higher 
.  leak  resistance  than  that  of  the  first 
audio  amplifying  tube.  (GL2)  =1.0 
megohm,  (GL3)  =5.00  megohm,  and 
(GL4)  =25.00  megohm.  This  arrange- 
ment gives  a  stronger  bias  to  the  grids 
on  the  tubes  which  are  most  heavily 
loaded,  and  therefore  results  in  a  better 
distribution  of  amplification  through  the 
three  stages.  The  output  of  the  sixth 
tube  (T6)  leads  to  the  output  jack  (Jl). 

A  full  90  volts  must  be  maintained  on 
the  plates  of  all  amplifier  tubes,  and  where 
possible,  this  should  be  increased  to  112.5 
volts  as  the  choke  and  resistance  coupling 
demands  a  higher  voltagethan  thestraight 
transformer  coupling  ordinarily  used. 
Two  vertical  type  45  volt  blocks  will 
take  up  the  minimum  amount  of  space 
in  the  cabinet  when  the  batteries  are 
carried  in  the  cabinet,  but  a  third  small 
22.5  volt  block  will  greatly  improve  the 
performance  by  raising  the  voltage  tc 
112.5  volts.  The  great  trouble  with  a 
portable  set  is  to  get  the  batteries  into 
place  without  monopolizing  all  of  the 
cabinet  space.  When  the  set  is  built  for  • 
ordinary  stationary  service,  then  we  can 
use  three  45  volt  blocks  of  "B"  battery, 
giving  135  volts,  and  will  thus  obtain 
the  maximum  output  of  the  tubes.  The 
small  size  "B"  batteries  must  be  used 
for  the  portable  set. 

Filament  or  "A"  batteries  are  to  be 
No.  6  cells  and  are  connected  up  in  series 
to  give  a  total  of  4.5  volts  across  the 
rheostat.  When  possible,  these  should 
be  square  batteries  so  that  the  maximum 
amount  of  battery  material  can  be  put 
into  a  minimum  of  space.     The  demand 


RADIO  AGE  for  May,   1925 


of  the  six  tubes  is  slightly  greater  than 
that  ordinarily  recommended  for  con- 
tinuous service  (0.36  ampere),  but 
with  careful  handling  they  can  be  made 
to  last  for  a  long  time  before  replacement 
becomes  necessary. 

Reason  for  Six  Tubes 

WITH  transformer  coupling  on  both 
radio  frequency  and  audio  frequency 
stages,  a  five  tube  set  is  commonly  built 
with  two  radio  stages,  detector,  and  two 
audio  stages.  With  choke  coils  in  the 
radio  stages  and  resistance  coupling  in 
the  audio  stages,  the  amplifying  power 
of  the  tubes  is  somewhat  reduced  so 
that  one  more  tube  will  be  required  to 
give  the  same  results.  However,  this  is 
more  than  compensated  for  by  the  sim- 
plicity of  the  controls  and  the  clear 
toned,  noiseless  operation  of  the  set. 
It  has  a  far  better  tone  than  with  the 
usual  arrangements  and  can  be  handled 
by  the  rawest  novice  in  radio. 

Fig.  3,  showing  the  front  elevation  of 
the  panel  and  cabinet,  gives  a  good  idea 
of  the  general  arrangement  of  the 
receiver  when  designed  as  a  portable  set. 
The  cabinet  is  really  divided  into  two 
parts,  (1)  the  upper  portion  covered  by 
the  panel  being  for  the  radio  circuit 
proper  while  (2)  the  lower  compartment 
houses  the  "A"  and  "B"  batteries.  As 
this  is  a  special  arrangement,  the  cabinet 
and  panel  will  have  to  be  made  specially 
for  the  job  and  it  is  not  likely  that  a  ready- 
made  cabinet  or  panel  can  be  found  which 
will  exactly  fit  the  conditions. 

In  the  front  view  of  Fig.  3  we  see  that 
the  panel  contains  all  of  the  controls, 
and  also  the  three  binding  posts  for  "the 
aerial  (ANT-X1-GND).  The  dial  of  the 
tuning  condenser  is  at  (CI),  and  for 
accuracy  this  should  be  a  four-inch  dial 
with  some  sort  of  vernier  arrangement, 
as  the  tuning  is  exceedingly  sharp. 
The  rheostat  control  (R)  for  the  detector 
tube  is  at  the  right  of  the  condenser  dial. 
The  battery  switch  for  turning  the  "A" 
battery  current  on  and  off  is  at  "SW" 
and  the  output  jack  is  (Jl).  In  the 
upper  right  hand  corner  of  the  panel  is 
the  grid  switch  (T)  by  which  the  set 
can  be  thrown  over  from  flat  top  aerial 
to  loop  operation.  This  is  all  there  is 
to  the  control  of  the  set  and  its  external 
connections. 

As  will  be  seen  from  the  side  sectional 
view,  Fig.  3A,  the  panel  is  set  back  from 
the  front  edge  of  the  cabinet  so  that  the 
front  door  will  clear  the  knobs  and  dials. 
The  door  swings  on  two  hinges  (h)  and 
is  just  large  enough  to  cover  the  panel, 
the  top  of  the  battery  compartment 
being  at  the  lower  edge  of  the  door. 
Any  suitable  catch  or  lock  (I)  can  be 
used  on  the  left  hand  edge  of  the 
cabinet  for  fastening  the  door,  and  a 
lock  is  not  a  bad  idea  even  in  the  home, 
as  it  prevents  children  from  tampering 
with  the  set.  At  the  top  is  a  leather 
handle  (G)  fastened  to  the  cabinet  by 
standard  hardware  that  can  easily  be 
obtained  from  a  trunk  or  suitcase  house 
or  from  some  hardware  stores.  The  lower 
battery  compartment  door,  just  below  the 
panel,  is  shown  closed.  It  is  through  this 
opening  that  we  replace  the  batteries. 
Blueprints  of  th 


'  1 1HE  finish  of  the  cabinet  depends 
-*-  upon  the  taste  and  ingenuity  of  the 
builder.  It  can  be  polished  with  wax  or 
varnished  in  natural  wood  finish,  or 
it  can  be  covered  with  leatherette  or 
similar  black  grained  covering  material. 
If  leatherette  is  used,  then  all  of  the 
corners  must  be  well  rounded  off  so  that 
the  material  will  not  get  loose  or  buckle 
along  the  edges.  The  front  face  of  the 
battery  compartment  door  comes  flush 
with  the  face  of  the  cabinet  and 
panel  door;  hence  this  part  is  given  the 
same  finish  as  the  outside  of  the  cabinet. 
Rubber  pads  or  feet   (i)  prevent  the  set 


BILL  OF  MATERIALS  USED 


The  following  Ii 
izes.  The  parts 
nee  letters  used  i 
an  be  seen  t 


rill  give  the  materials  used  and  th« 
■  listed  according  to  the  same  refe 
wings  so  that  their  relatic 


l  glaoc 
PORTABLE  RECEIVER  MATERIALS 

"A"— 3  Filament  "A"  Dry  Batteries,  1.5  volt.  No.  6. 

ANT — 1  Loop  aerial  (optional),  2  Ft.  Square. 

"B" — 2   "B"   Tlate  Batteries.   Vertical  type.   45  Volt 

"C"— 1  "C"  Bias  Battery.  Three  call,  small.  4.5  volts 

CI— 1  Vernier  Variable  Condenser  [23  plate) ,  0.0005  ml" 

CC — 2    100   Millihenry   Choke   coiLs.    or   audio   trans- 
former secondary  coils. 

D — 1  Special  cabinet,  as  specified 

E — 1  Special  Panel,  as  specified  in  i 
Bakelite. 

F-H — 2  Sne-cial  Sli'lves.  as  specified  iu  drawings.  3-16 
inch  Bakelite  5"x6K" '■ 

G — 1  Carrying  Handle  Complete,  Standard. 

GL1-1  Grid  Leak.  1.00  Megohm. 

GL2 — 1  Grid  Leak,  1.00  Meghom. 

GL3— lQrid  Lejk.  5.00  Megohm. 

GL4— 1  Grid  Leak.  25.00  Megohm. 

h — 4  Hinges  or  butts.  Standard. 

I — 2  Lock  Catch,  Standard. 

i — 1  Rubber  pads  or  feet.  Medium  Si/.e. 

Jl— 1  Single  Circuit  .lack.  Standard. 

Kl — 1  Fixed  Condenser,  Mica  dielectric.  0.002  mf. 

K2 — 1  Fixed   Condenser.    Mica  dielectric.    Grid   clips. 
U. 01)025  mf. 

K3 — 1    Fixed     Condenser.     Mica    dielecric.    0.005    or 
0.006  mf. 

K4 — 1    Fixed    Condenser.    Mica    dielectric.    C.C05    or 
0.006  mf. 

K5 — 1    Fixed    Condenser.    Mica    dielectric.    0.005    or 
0.006  mf. 

L — 4  Brass  Angle  Brackets,  Standard. 

L1-L2 — 1  Aperiodic  Type  Coupler,  Standard. 

M1-M2-M3— 3  50.000     ohm    Resistor    Units, 

K — 1  Filament  Rheostat.  30-40  ohms. 

rl-r2,  etc. — 5    Automatic    Fila.    Controls     '  Amperites) 
199-4.5  volts. 

SW — 1  Battery  Switch.  Standard. 

T — 1  Tap  Switch.  Standard. 

t — 2  Contact  points,  with  two  stops.  Standard. 

T1-T2.  etc. — 6  Tubes.  "199. " 

U — 6  Absorber  Base  Tube  Sockets.  "199"  Type. 

40"  Tinned  Square  Copper  Bus  Wire.  No.  14. 

75  Solder  Clips.  Tinned.  Standard. 

3  Binding  Posts.  Composition  Caps.  Standard. 

Z — I  Brass  angle  connections.  Standard. 

V — 1  Leak,  1  megohm. 

VM — Filament  voltmeter.  0.8  volts. 


from  scratching  finished  surfaces  on  which 
it  may  be  placed,  and  further,  they 
prevent  or  help  to  prevent,  the  ringing 
microphonic  noises  experienced  with 
"199"  tubes. 

Shelf  for  Tubes 

The  side  sectional  view  of  Fig.  3A  shows 
that  a  shelf  (F)  is  used  for  carrying  the 
first  three  tubes,  and  that  this  shelf  is 
attached  to  the  panel  (E)  by  means  of 
brass  angle  brackets  (L).  The  shelf  (F) 
carries  the  first  two  tubes  (T1-T2)  of 
the  radio  frequency  circuit  and  also  the 
detector  tube  (T3).  Below  the  upper 
shelf  is  the  lower  shelf  (H)  which  carries, 
the  three  audio  tubes  (T4— T5— T6).  As 
the  resistance  units  and  other  parts  of 
the  circuit  are  carried  on  the  underside 
of  the  shelves  with  the  sockets  on  top, 
we  must  be  sure  to  leave  room  to  accom- 
modate the  height  of  the  tubes  over 
their  sockets,  plus  the  thickness  or  height 
of  the  resistance  units  and  the  condensers, 
plus  clearance. 

The  material  used  for  the  cabinet  can 
be  5-16  inch  or  3-8  inch  thick,  but  if  care- 
fully constructed  with  dovetailed  or 
matched  corners,  will  be  perfectly  safe 
when  built  of  5-16  inch  stock.  The 
e  Six-Tube  "Portatron"  on  Two 


The  Magazine  of  the  Hour  35 

bakelite  panels  should  not  be  less  than 
3-16  inch  and  this  also  covers  the  shelves 
which  should  be  of  the  same  material 
as  the  panels;  that  is,  hard  rubber,  bake- 
lite or  formica.  The  shelves  carry  the 
wiring  and  many  of  the  current  carrying 
parts  so  that  their  insulating  value  should 
be  fully  equal  to  that  of  the  panels. 

We  cannot  go  further  into  the  details 
of  the  cabinet  construction,  but  the  con- 
struction will  be  clearly  seen  by  those 
who  are  competent  to  undertake  work 
of  this  sort,  and  if  one  is  not  sure  of  being 
able  to  build  this  cabinet,  the  drawings 
are  amply  dimensioned  for  a  practical 
cabinet  maker.  If  you  give  the  job  to 
a  cabinet  maker,  I  suggest  that  you  also 
give  him  the  panels  and  shelves  so  that 
he  can  get  a  good  fit  betwen  the  edges 
of  the  panel  and  the  rabbet  of  the  cabinet. 

Arrangement  of  Apparatus 

TCMG.  4  shows  the  arrangement  of  the 
-*-  apparatus  as  seen  from  the  rear  of  the 
panel.  The  six  tube  sockets  (U)  are 
placed  in  groups  of  three  on  the  two 
shelves  (F)  and  (H),  and  the  outlines  of 
the  tubes  are  indicated  by  thin  dot  and 
dash  lines  so  that  the  allowance  for  shelf 
clearance  can  be  easily  seen.  The  tubes 
are  numbered  so  that  their  relation  to 
the  circuit  drawings  of  Figs.  1  and  2  can 
be  easily  followed,  and  the  sockets  can 
be  located  in  the  same  way.  Fig.  3A 
and  Fig.  4  can  be  used  in  combination, 
thus  obtaining  the  side  and  rear  eleva- 
tions of  the  assembly. 

It  will  be  seen  that  the  shelves  are  cut 
off  at  the  right  in  Fig.  4  to  accommodate 
the  variable  tuning  condenser  (CI)  and 
the  tuning  inductance  (LI— L2).  On 
the  lower  sides  of  the  shelves  will  be  seen 
the  coupling  resistances,  grid  condenser, 
gridleaks  and  the  wiring.  In  making 
allowance  for  the  space  between  shelves, 
measure  the  height  of  the  tube  plus  the 
height  of  the  socket,  plus  a  little  more 
clearance  so  that  the  tubes  can  be  taken 
out  of  the  sockets  and  replaced  without 
tearing  the  set  to  pieces.  In  other  words, 
the  true  height  of  the  socket  assemblv 
is  the  sum  of  the  tube  height,  plus  the 
socket  height,  plus  }4  inch  clearance 
between  the  lower  end  of  the  tube  and 
the  top  of  the  socket. 

The  arrangement  of  the  battery  com- 
partment in  general  with  the  batteries 
in  place  is  marked.  Strong  flat  springs 
made  from  flat  spring  brass  plates  bear 
on  one  side  of  the  batteries  and  hold  them 
in  place  against  jolts  and  jars  when  the 
set  is  being  carried.  Connections  between 
the  apparatus  and  batteries  are  made  by 
means  of  flexible  fixture  wire  which  can 
be  obtained  from  any  electrical  store. 
This  is  very  flexible  and  well  insulated, 
and  makes  an  ideal  connection.  The  ends 
of  the  fixture  wire  should  be  provided 
with  "spade"  type  tips  soldered  to  the 
copper  strands,  and  these  make  a  perman- 
ent contact  with  the  connection  screws 
which  is  easily  attached  and  which  does 
not  loosen  under  ordinary  conditions. 
Do  not  attempt  placing  the  strands  of 
wire  directly  under  the  binding  screws, 
for  when  connected  up  in  this  way  they 
are  almost  certain  to  get  undone. 
(Turn  to  page  38) 


Pages  Following 


COPYF/GHT  tSZG^AJ- ': 
&/)D/Os46E,  /A/C       TP^T.  r£M£0 
CWCrfGO, /££-■ 


vMlds&m&i 


38 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


Economy  of  Arrangement  Is  Vital 


(  Continued  from  page  35) 
Alternative     Arrangement 

AS  WILL  be  seen,  the  part  of  the 
assembly  taken  up  by  the  receiver 
proper  is  very  small,  the  panel  measuring 
10J4  long  and  \\yi  deep,  but  for  some 
purposes  the  total  height  with  the 
batteries  included  may  be  too  great  to 
be  practicable.  In  such  a  case,  the 
battery  compartment  can  be  made 
separate,  terminating  the  receiver  por- 
tion at  the  board  shown  running  over 
the  tops  of  the  batteries.  This,  however, 
makes  it  necessary  to  reconnect  the  bat- 
teries every  time  that  the  receiveris  set  up 
and  as  a  result  it  is  a  decided  nuisance. 

As  laid  out  in  the  drawings,  there  is 
ample  room  for  a  fifth  "B"  battery  if 
it  is  desired  to  operate  with  a  plate 
voltage  of  WlV%  volts,  or  a  sixth  "B" 
battery  if  we  wish  to  operate  at  135 
volts.  Further,  there  is  room  for  one 
spare  "A"  battery  if  it  is  desired  to  carry 
this   replacement   along   on   a   trip. 

The  voltmeter  (VM)  is  a  very  desir- 
able instrument,  particularly  when  dry 
cell  "A"  batteries  are  used,  for  it  at 
once  indicates  the  drop  in  voltage  due 
to  weakening  batteries.  Unless  we  have 
some  means  of  testing  the  voltage 
occasionally,  we  are  likely  to  believe 
that  the  set  is  out  of  order  when  the 
voltage  drops,  and  waste  much  time 
chasing  for  trouble  in  the  wiring  when 
the  difficulty  actually  exists  in  the 
cells.  Just  because  automatic  filament 
controls  are  installed  for  the  regulation 
of  the  filament  current  is  no  reason 
why   the  voltmeter   should   be   omitted. 

Voltmeters  must  be  connected  properly 
according  to  polarity,  and  you  must 
be  guided  by  the  markings  on  the  instru- 
ment. If  the  polarity  is  wrong,  then 
the  needle  indicator  will  be  thrown 
against  the  wrong  end  of  the  scale. 
The  size  of  the  voltmeter  should  be  so 
chosen  that  the  full  voltage  will  bring 
the  needle  near  or  slightly  beyond  the 
center    of    the    graduated    scale    where 


the  divisions  are  the  largest,  and  the 
battery  voltage  should  not  throw  the 
needle  to  the   far  end   of  the   scale. 

Suppressing  Oscillations 

Free  oscillations  in  the  radio  fre- 
quency stages  are  the  greatest  difficulty 
in  the  construction  of  a  radio  frequency 
or  reflex  type  of  receiver,  and  we  must 
devise  some  system  for  stopping  these 
oscillations  if  we  expect  to  get  the  full 
output  of  the  set.  In  fact,  most  of  the 
trouble  reported  with  sets  having  radio 
frequency  stages  can  be  traced  to  im- 
proper or  imperfect  methods  of  damping 
down  the  oscillations.  There  are  a 
number  of  methods  of  stopping  oscilla- 
tions, among  which  are  the  potentio- 
meter, neutralizing  condensers,  bias  bat 
teries,  etc.,butinthis  receiver  we  have  sim 
plified  the  problem  by  the  use  of  a  plate  re 
actacnecoil  marked  (L3)  on  the  diagrams. 

Coil  (L3)  consists  of  four  or  five  turns 
of  wire  wound  on  the  end  of  the  tuning 
coil.  One  end  of  this  coil  is  connected 
to  the  plate  of  the  first  radio  tube  as 
shown,  while  the  other  end  is  left  opened 
or  is  unconnected.  As  one  end  is  opened, 
only  capacitative  current  will  flow  from 
the  plate  into  the  coil,  and  the  magnetic 
coupling  is  therefore  very  feeble,  as  it 
should  be.  Some  little  experimenting 
will  be  required  in  adjusting  this  coil 
before  it  just  stops  the  oscillations. 
It  may  be  that  the  plate  connection 
must  be  connected  to  the  other  end  of 
(L3),  or  that  the  whole  coil  must  be 
wrapped  on  the  other  end  of  the  tube. 
Varying  the  number  of  turns,  or  the 
distance  of  (L3)  from  (L2)  may  be 
required.  Just  because  you  have  not 
hit  the  proper  combination  on  the  first 
trial  is  no  proof  that  it  will  not  work. 
The  losses  are  at  a  minimum  with  this 
arrangement,  and  there  are  no  separate 
controls  as  when  a  potentiometer  is  used. 

In  addition  to  the  compensating  coil 
(L3),  the  "C"  battery  will  be  an  aid  in 
keeping  down  oscillations  and  increasing 
the    sensitivity    of    the    first    two    tubes. 


In  the  center,  and  at  the  bottom  of 
Fig.  1,  will  be  found  a  detail  of  a  small 
radio  frequency  choke  coil  which  can 
be  used  when  an  audio  frequency  trans- 
former secondary  is  not  available.  This 
consists  of  about  450  turns  of  No.  36 
D.  S.  C.  wire  wound  on  a  cardboard 
or  bakelite  tube  as  shown,  and  is  mounted 
on  the  upper  shelf  (F)  of  the  set.  Some 
little  experimenting  may  be  required 
to  get  the  most  effective  number  of 
turns,  but  the  coil  is  not  very  critical 
to  the  turns,  and  for  most  apparatus  the 
number  of  turns  shown  will  come  very 
close  to  the  best  effect.  We  must  have 
enough  turns  so  that  the  tubes  will  not 
paralyze  on  the  higher  wavelengths 
through  leakage  of  the  R.  F.  current 
to  the  "B"  battery. 

In  the  lower  right  hand  corner  of 
Fig.  1  is  a  detail  of  the  resistor  assembly- 
used  in  the  audio  frequency'  stages. 
We  can  assemble  the  resistors  and  grid 
leaks  on  the  shelves  by  means  of  clips 
as  shown,  or  better  yet,  we  can  buy 
these  completely  assembled  units  from 
our   advertisers,   at   a   reasonable   figure. 

Summary 
TN  tuning  this  set,  the  adjustment  of 
-*-  the  detector  rheostat  (R)  is  of  great 
importance,  for  there  is  one  position 
of  the  rheostat  where  the  detector  tube 
is  the  most  sensitive  and  gives  the 
greatest  volume.  This  generally  occurs 
when  the  rheostat  is  about  one-half  on, 
and  it  is  seldom  necessary  to  turn  on 
this  tube  to  full  brilliance  as  with  the 
amplifier     tubes. 

In  giving  his  Five  Tube  Radio  Fre- 
quency Receiver  in  the  April  issue  the 
name,  "Amplex  Receiver,"  our  blue  print 
editor  inadvertently  used  the  trade-name 
of  a  receiver  manufactured  by  the  Amplex 
Instrument  Laboratories  of  New  York 
City.  RADIO  AGE  wishes  to  inform  its 
readers  that  the  set  described  in  the  blue- 
print section  of  April  issue  was  in  no  way 
related  to  the  receiver  made  by  the 
Amplex  concern. 


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July,  1924 

■A  Portable  Tuned  Impeda 


irferen 


January,  1924 

— Tuning  Out 
— Filters. 
— A  Junior  Super-Heterodyne. 
— Push-Pull  Amplifier. 
— Ro3enbloom  Circuit. 
March,  1924 

— An  Eight-Tube  Super-Heterodyne. 
— A  simple,  low  loss  tur 
— A  Tuned  Radio  Freq> 
— Simp'e  Reflex  Set. 
April,  1924 

— An  Efficient  Super-Heterodyne 
—A  Ten-Dollar  Receiver. 
— -Anti-Body  Capacity  Hookup*. 
-Reflexing  the  Three-Circ  ""  ' 


Wave   Traps — Elir 


■  Amplifier 


—Index  and  firBt  two  installment*  of  Radio  Age  Data  Sheets.        October,  1924 

__-..  — An  K'L-ily  Miidi'  i-mper-Het. 

May,  1924 

— Construction  of  a  Simple  Portable  Set. 
— Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheets. 
June,  1924 

— Important  Factora  in  Constructing  a   Super-Heterodyne 
— A  Universal  Amplifier. 
—A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 
— -Radio  Age  Data  Sheets. 


:  Reflex. 
— Operating  Detector  Tube  by  Grid  Bias. 
— A  Three-Tube  Wizard  Circuit. 
— Data  Sheets. 
August,  1924 

— Breaking  Into  Radio  Without  a  Diagram. 
— The  English  4-EIement  Tube. 
— Filtered  Heterodyne  Audio  Stages. 
— An  Audio  Amplifier  Without  an  "A"  Battery. 
— Data  Sheets. 
September,  1924 

— How  Careful  Mounting  Will  Improve  Reception. 
— One  Tuning  Control  for  Hair's  Breadth  Selectivity. 
— Four  Pages  of  Real  Blueprints  of  a  New  Baby  Heterodyne 
_  and   an  Aperiodic  Variometer  Set. 
i  Sheets. 


Radio  and  Two  Audio  for  Clear  Tone 
— A  Simple  Regenerative  Set. 
—The  Ultradyne  for  Real  DX. 
— Real  Blueprints  of    a    3-Tube    Neutrodyne 

Reflex  Set. 
November,  1924 
— Blueprints    of   a    Single    Tube    Loop    Set   s 

Feedback   Receiver. 
— A  3- Tube  Low  Loss  Regenerator. 
— Mastering  the  3-Circuit  Tuner. 


The  supply  is  limited,   so  enrich  your 

December,  1924 

— Blueprints  of  a  New  8-Tube  Super-Heterodyne. 
— How  to  Make  a  Receiver  that  Mininuzes  Static. 
—A  Trans-Atlantic  DX  Receiver. 

— How  to  Make  a  Home  Made  Battery  Charger  and  a  Loud 
Speaker  at  a  Small  Cost. 

January,  1925 

— A  Reflexed  Neutrodyne 

— A  Six  Tube  Super-Het. 

— An  Efficient  Portable  Set. 

— A  Tuned  Plate  Regenerator. 

— Making  a  Station-Finder.J, 

February,  1925 

— A  Sure  Shot  Super-Het. 

— A  Three  Circuit  Regenerator. 

— A  Real.  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex. 

March,  1925 

— A  Permanent  Super-Het. 

— A  5-Tube  R.  F.  Receiver. 

— How  to  Wind  Low  Loss  Coils. 

— A  Short  Wave  Receiver 

— Blue  Prints  of  a  Two-Tube  Ultra  Audion  and  a  Re- 
generative Reflex. 

April.  1925 

— A  3-Tube  Portable  Set 

— "B"  Voltaee  from  the  A.  C.  Socket 

— An  Amplifier  for  the  3-Circuit  Tuner 

— Blueprints  of  a  Five-Tube  Radio  Frequency  Receiver 


RADIO  AGE,  Inc. 


500  N.  Dearborn  St.,  Chicago 


RADIO  AGE  for  May,   1925 


The  Magazine  of  the  Hour 


39 


Radio  Age  Institute 

Manufacturers'  Testing  Service 

MEMBERS  of  the  staff  o*  RADIO  AGE  will  be  pleased  to  test  devices 
and  materials  for  radio  manufacturers  with  the  object  of  deter- 
mining their  efficiency  and  worth.  All  apparatus  which  meets  with 
the  approval  of  various  tests  imposed  by  members  of  the  technical 
staff  of  RADIO  AGE  will  be  awarded  our  endorsement,  and  the  seal 
shown  to  the  right  will  be  furnished  free  of  charge.  Materials  for 
testing  should  be  sent  to 

RADIO  AGE  INSTITUTE 

504  N.  Dearborn  Street,  Chicago,  111. 


DEVICES 

displaying  this  seal 
have  been  tested 
and  approved  by 
the  RADIO  AGE 
INSTITUTE. 

Apparatus  illus- 
t  r  a  t  e-d  and  des- 
cribed below  has 
successfully  passed 
our  tests  for  May, 
1925. 


Test  No.  47.  THE  QUA*  I  CONDENSER.  Sub- 
mitted by  the  Quam  Radio  Corporation,  of  Chicago, 
J II.  The  manufac- 
turers claim  this  con- 
denser to  be  the 
lowest  loss  commer- 
cial condenser  made. 
The  radio  frequency 
measurements  taken 
of  this  condenser  in 
our  laboratories  in- 
dicated they  are 
not  exaggerating  in 
their  claims.  This 
condenser  has  a  resist- 
ance at  least  as  low 
as  the  standard  to 
which  it  was  compared,  for  the  whole  broadcast 
frequency  range  and  for  various  values  of  capacity. 
The  very  low  losses  are  attributed  to  the  high  leak- 
age resistance  and  low  dielectric  losses,  due  to  the  use 
of  the  pyrex  end  plate,  which  is  well  out  of  the  dense 
part  of  the  field.  Arrived  in  good  condition  and 
satisfactorilv  passed  the  tests  and  requirements  of 
RADIO  AGE  Institute. 


£^\] 


Test  No.  48.     The  ULTRA  VERNIER  Tuning 
Control.    Submitted  by  the  Phenix  Radio  Corpora- 
tion of  3-9 


Beekman 
Street, 
N  e  w 
York 
City. 
This  tun- 
ing con- 
trol was 
designed 
by  the 
w  e  I  1  - 

f~^  known 
radio  e  n- 
f  g  i  n  e  e  r, 
R.  E.  La- 
cault,  and 


enough  to 
give  hair- 
splitting accuracy  without  making  tuning  tiresome. 
It  is  geared  20  to  1.  The  face^of  the  dial  remains 
ri^id  on  the  panel.  The  rotor  or  moving  arm  turns 
from  the  vernier  knob  at  the  bottom  of  the  dial. 
The  real  usefulness  of  this  dial  in  quick  and  accu- 
rate tuning  is  the  provision  made  for  the  fan  to  in- 
dicate on  the  dial  with  pencil  or  ink  the  station  he 
desires  These  units  are  very  attractive  in  appear- 
ance Satisfactorilv  passed  the  tests  and  require- 
ments of  RADIO  AGE  Institute. 

Tes'  No  4Q  DUPLEX  MATCHED  CONDEN- 
SERS^  "  Submitted  by  the  Duplex  Condenser  and 
Radio  Corporation  of 
42  Flatbush  Ave.,  r~ 
Brooklyn,N.Y.  These 
condensers  come  in 
sets  of  three,  and  their 
advantage  lies  in  sim- 
plified logging,  for 
their  use  affords  uni- 
form dial  settings  for  I 
neutrodyne  and  all  \ 
other  tuned  r.  f.  re-  < 
ceivers.  Tests  proved 
that  Duplex  conden-  [ 
sers  are  accurately  j 
made  and  do  not  I 
change  capacity  un- 
less varied  by  the 
operator.  Rotor  plates 
are  die-cast  in  their 
s  h  a  ft  and  s  t  a  t  o  r 
plates  are  forced  into 

undersize  slots  milled  in  the  end  posts.  The  con- 
denser submitted  was  a  21  plate.  Satisfactorily 
passed  the  tests  and  requirements  of  the  RADIO 
AGE  Institute. 


Test  No  50.  The  CARBORUNDUM  CRYSTAL 
DETECTOR.  Submitted  by  the  Carborundum 
Company,  Niagara  Falls,  N.  Y.  This  detector  con- 
tains a  special  carborundum  made  for  radio  purposes. 
Tests  in  our  laboratory  revealed  that  this  detector 
sjives  volume  equal  to  any  and  in  many  cases  more 


than  any  other  crystal.  When  tested  for  selectivity, 
tuning  was  so  sharpened  that  interference  was  cut  to 
a  minimum.  While  other  crystals  burned  out  by  the 
application  of  repeatedly  strong  signals,  the  Car- 
borundum detector  stood  up  well  for  the  period  in 
which  it  was  used.  The  detector  comes  marked  so 
that  in  a  single  circuit  crystal  set  one  end,  marked 
"A"  is  connected  to  the  aerial,  and  the  end  marked 
"G"  goes  to  the  ground.  For  other  sets,  the  "A"  end 
connects  directly  to  the  grid  connection  on  the 
secondary  of  the  radio  transformer  or  coupling  coil, 
and  the  "G"  end  goes  to  the  phones  or  to  the  plate 
connection  on  the  primary  of  the  audio  transformer. 
Satisfactorilv  passed  the  tests  and  requirements  of 
RADIO  AGE  Institute. 

Test  No.  51.  NA-ALD  SOCKETS.  Manufac- 
tured and  submitted  by  the  Alden  Manufacturing 
Co.  of  Springfield,  Mass. 
These  sockets  are  made  of 
high  grade  moulded  Bakelite 
by  a  special  process.  Ac- 
cordingly the  losses  were 
very  low.  The  finish  on 
these  sockets  is  permanent 
and  stood  up  well  over 
extensive  use.  Na-Ald  sock- 
ets are  guaranteed  indefi- 
nitely. Satisfactorily  passed 
the  tests  and  requirements 
of  the  RADIO  AGE  Institute. 


Test  No.  52.  CRESCENT  LAVITE  RESIS- 
TANCES. Manufactured  and  submitted  by  the 
Crescent  Radio  Sup- 
ply Co.  of  9  Liberty 
St.  .Jamaica,  N.  Y. 
■  i>J..  J^H  ^H^  These  resistances, 
when  used  in  place  of 
iron  core  transformers 
in  audio  amplification,  were  found  to  positively 
eliminate  distortion.  Besides  giving  pure  tone  quality, 
they  reduce  B  battery  consumption  and  make  a  C 
battery  practically  unnecessary  in  most  cases.  They 
were  mounted  in  our  tests  under  an  ordinary  gang 
socket.  Satisfactorily  passed  the  tests  and  require- 
ments of  the  RADIO  AGE  Institute. 


Test  No.  53.  NA-ALD  SUPER  DELUXE  DIAL. 
Submitted  by  the  Alden  Manufacturing  Company 
of  Spring- 
field .Mass. 
Dial  No. 
3044  for 
1-4  inch 
shaft  was 
tested  in 
several 
RADIO 
A  G  E 
hookups 
and  found 
efficient 
and  at- 
tractive 
besides 

being  economical  in  price.  It  was  found  that  gradua- 
tions in  these  dials  have  been  carefully  designed  to 
make  positive  and  rapid  tuning  possible.  They  are 
made  of  genuine  Bakelite  with  brass  bushing.  Satis- 
factorily passed  the  tests  and  requirements  of  the 
RADIO  AGE  Institute. 

Test  No.  54.  THE  HANDY  CONDENSER 
CLIP.  Manufactured  and  submitted  by  the  Ridge 
Manufacturing 
Com  pany  of  3818 
N.  Ridgeway  Ave., 
Chicago,  111.  This 
clip  was  designed 
for  the  purpose  of 
giving  greater  care 
to  fixed  condensers 
in  radio  receivers. 
This  clip,  for  use 
with  fixed  condens- 
ers, was  tested  over 
a  period  of  thirty 
days  and  it  was 
found  that  signal 
strength  was  con- 
siderably augment- 
ed. It  is  useful  for 
preventing  the 
change  of  capacity 

in  the  fixed  condenser,  shorting  the  circuit  or  opening 
the  circuit,  and  otherwise  generally  protecting  the 
condenser  from  outside  damage.  Satisfactorily 
passed  the  tests  and  requirements  of  the  RADIO 
AGE    Institute. 


Test  No.  55.  The  GLOBE  HEADSET.  Manu- 
factured and  submitted  by  the  Globe  Phone  Manu- 
facturing Com- 
pany of  Reading, 
Mass.  The  Globe 
headset  was  test- 
ed both  on  local 
and  distant,  sta- 
tions in  Chicago 
and  in  every  in- 
stance clarity  of 
tone  as  well  as  a 
surprising  "sweet- 
ness" on  high 
notes  was  evi- 
dent. These  re- 
ceivers are  super- 
sensitive, furnish- 
ed with  brass 
cases,  high  po- 
lish nickel  finish, 
ore  winding  is 
shielded,  magnets  are  of  drop  forged  steel,  rust  proof 
and  terminals  are  concealed.  The  adjustment  on  the 
head  is  comfortable.  Tests  for  volume  also  produced 
remarkable  results.  Satisfactorily  passed  the  tests  and 
requirements  of  the  RADIO  AGE    Institute. 

Test  No.  56  The  TRI-JACK  and  B  M  S  Jack 
Submitted  by  the  Brooklyn  Metal  Stamping  Co.  of 
71S  Atlantic  Ave.,  Brook- 
lyn, N.  Y.  The  Tri-Jack, 
shown  in  the  illustration, 
was  found  to  eliminate 
capacity  effects  almost 
entirely.  1 1  is  a  single 
circuit  and  double  circuit  | 
jack  combined  and  the  i 
very  latest  in  radio  de-  ' 
velopment.  It  is  one-  | 
third  the  size  of  the  ordi-  | 
nary  jack.  It  is  made  of 
moulded,  solid  Bakelite 
and  the  overall  dimen- 
sions are  one  inch  by  one 
inch.  The  terminals  are 
clearly  marked.  The  B. 
M.  S.  Jack,  submitted 
with  the  Tri-Jack  for  test, 
was  also  found  efficient 
for  single  open  circuit 
work.  It  is  designed  for  easy  soldering.  Lugs  are 
spaced  to  be  always  accesssible.  The  lug  tips  are 
cupped.  Satsfactorilv  passed  the  tests  and  require- 
ments of  RADIO  AGE  Institute. 

Test  No.  57. 
AMPERITE. 
Manufactured  by 
the  Radiall  Co.  50 
Franklin  Street, 
NewYork.N.Y.  An 
automatic  resist- 
ance used  in  place  of  the  customary  rheostat.  The 
small  tube  that  contains  this  resistance  element  is 
equipped  with  two  metal  ends  which  are  used  as 
terminals  when  it  is  inserted  in  the  base  supplied 
with  the  instrument.  Being  automatic  in  action  and 
needing  no  adjustment,  it  will  be  found  very  useful 
for  controlling  the  filament  temperature  on  ampli- 
fying tubes.  Tested  and  approved  by  RADIO  AGE 
Institute. 


Test  No.  58.  THE  CUT- 
LER-HAMMER TOGGLE 
SWITCH.  The  Cutler-Ham- 
mer Manufacturing  Com- 
pany have  recently  added  +o 
their  line  of  radio  products  a 
newToggleBatterySwitch.  It 
has  large  wipe  contacts,  posi- 
tive make-and-break  mech- 
anism, wide-spaced  terminals 
and  attractive  appearance. 
It  is  so  designed  as  to  embody 
the  best  features  of  its  type 
and  also  to  eliminate  every 
disadvantage.  The  mechanism  is  enclosed  in  a  dust 
proof  cover  and  the  metal  parts  are  attractively 
finished  in  polished  nickel.  The  switch  is  easily 
mounted  on  any  radio  panel  in  a  few  minutes,  and 
does  not  require  any  screws  or  measurements.  A 
lock  nut  is  provided  for  proper  adjustment  for  panel 
thickness-  When  installed,  a  flip  of  the  operating 
lever  with  the  finger  turns  the  current  "on"  or  "of. 
An  easy  and  convenient  type  of  switch  to  operate. 
Manufactured  by  the  Cutler-Hammer  Manufacturing 
Co.,  Milwaukee,  Wis.  Satisfactorily  passed  the 
tests  and  reouirements  of  RADIO  AGE  Institute. 


40 


RADIO  AGE  for  May,  1925 


What  the  Broadcasters  are  Doing 


World  s  Smallest  Studio  Now  on  the  Air 


Gay  Artists 
Perform  from 

WJJD's 
Bur  lap  Studio 


Radio  listeners  cannot  enjoy  Flo  Henry's 
bewitching  gaze,  as  shown  above,  but 
they  can  hear  her  equally  bewitching  voice 
from  WJJD's  burlap  studio  at  the  Ren- 
dezvous. 

(Photo  by  Connelly,  Chicago.) 


iS  a  contrast  to  tne  many  claims  of 
Z\  various  broadcasting  stations  thru- 
_/.  A-out  the  countryof  havingthe  largest 
and  most  elaborate  studios  for  radio 
programs,  there  recently  came  the 
announcement  from  WJJD  that  the 
world's  smallest  and  most  informal  studio 
was  now  on  the  air. 

When  arrangements  for  a  Chicago 
studio  were  made  by  Jack  Nelson, 
Managing  Director  and  Announcer  of 
the  Loyal  Order  of  Moose  Station  WJJD, 
and  this  studio  was  located  in  the  Palmer 
House,  Chicago,  and  called  the  Garod 
Studio,  it  was  found  that  awaiting  the 
completion  of  the  new  Palmer  House, 
there  was  no  orchestra  music  in  the  hotel. 
So  Jack  went  scouting  around  and  made 
arrangements  with  the  Rendezvous  Cafe 
management  to  broadcast  Charley  Straight 
and  his  Orchestra  every  night  as  a  part 
of  the  Chicago  program  offered  by  WJ J  D 
at   10:30  p.  m. 

He  then  noticed  that  many  of  the 
entertainers  there  had  voices  which  would 
broadcast  exceptionally  well  and  he  "got 
the  itch"  to  put  them  on  for  some  "hot" 
programs.  Their  work,  however,  pre- 
vented their  journeying  down  to  the 
elaborate  Garod  Studio  in  the  Palmer 
House,  so  the  "back-stage  studio"  idea 
was  conceived,  and  programs  are  now 
being  broadcast  every  Sunday  night  be- 
ginning at  midnight  (Central  Standard 
Time). 

Dressing  Room  as  Studio 

THERE  was  not  room  to  arrange  for 
a  studio  which  would  be  open  to  the 
guests  of  the  Rendezvous,  so  a  large 
dressing  room  back-stage  was  chosen; 
and  because  it  would  not  be  open  for 
inspection,  burlap  was  chosen  for  the 
material  to  deaden  the  room  and  make  it 
available  for  broadcasting. 

So  "Potato  Sack  Studio"  is  an  ap- 
propriate designation,  both  because  of 
its  hangings  and  size.      Here  the  regular 


entertainers,  (and  some  of  them  have 
been  there  as  long  as  two  years),  Lillian 
Bernard,  Flo  Henry,  Frank  Mason,  Jack 
O'Malley,  Billy  Gerber,  Margaret  White, 
— the  Red  Head  Gal  with  the  Uke, — 
Wanda  Goll,  Jimmy  Travers,  etc.,  "do 
their  stuff"  between  the  dances  played 
by  Charley  Straight  and  his  Orchestra. 
It  is  quite  a  trick  to  keep  the  "air" 
program  running  smoothly,  because  the 
entertainers  must  dress  for  one  of  their 
acts,  change  makeup,  do  their  bit  "on 
the  floor"  and  then  dash  into  the  Potato 


s 


And  here's  Charley  Straight,  himself, 
whose  syncopating  music  aggregation  furn- 
ishes the  jazz  regularly  from  WJJD,  begin- 
ning every  night  at  10:30  o'clock,  Central 
time. 


Sack  to  do  a  turn  "on  the  air,"  rush  out, 
change  clothes  again  for  the  next  show, 
and  repeat  three  or  four  times  a  night. 
Perhaps  that's  what  makes  this  program 
so  peppy. 

WJJD  has  received  hundreds  of  letters 
of  applause  on  this  feature.  It  just 
happens  there  are  few  stations  on  the 
air  at  that  time.  Miners  and  other 
workers  of  late  shifts  applaud  heartily 
because  it  gives  them  something  late 
Sunday  night  which  was  not  available 
before. 

Inasmuch  as  this  program  is  only  once 
a  week,  it  does  not  work  the  Rendezvous 
folks  too  hard.  It  certainly  couldn't  be 
done  every  night  or  they  would  all  be 


Lillian  Bernard  is  an  expert  at  character 
songs  and  popular  renditions.  She  has 
been  a  favorite  among  Chicago  cafe  fans 
for  years,  and  now  she's  a  favorite  among 
WJJD's  host  of  Sunday  night  listeners. 

(Connelly  Photo.) 


"wrecks,"  but  once  a  week  is  a  lot  of 
fun  and  as  Jack  Nelson  announces  from 
the  Potato  Sack,  "These  weekly  shows 
will  be  very  informal.  We'll  let  you  in 
on  all  our  secrets,  our  gayeties,  and 
perhaps  even  some  of  our  little  quarrels, 
so  that  you  will  almost  smell  the  grease 
paint  and  see  all  the  costumes." 

It  is  that  informality  that  makes  them 
just  what  they  seem:  a  good  time  by  a 
handful  of  stage  folk,  back  stage.  They 
seem  to  feel  that  they  are  not  putting  a 
program  out,  but  all  the  folks  listening 
in  are  really  listening  in, — sort  of  eaves- 
dropping on  their  little  weekly  get- 
together. 

Ralph  Helps,  Too 

TNCIDENTALLY,  Ralph  Shugart,  the 
-*-  engineer  of  WJJD,  deserves  a  good 
word  for  the  excellent  way  in  which  he 
handles  the  Chicago  broadcasting.  Moose- 
heart  is  37  miles  west  of  its  Chicago 
central  (the  Garod  Studio  in  the  Palmer 
House),  and  the  Rendezvous  Cafe  is 
another  four  miles  North  from  there,  and 
the  lines,  amplifiers  and  microphones  are 
certainly  well  handled. 

While  the  "Potato  Sack  Studio"  will 
be  used  according  to  the  present  plans 
but  once  a  week,  that  does  not  mean  that 
WJJD  will  not  broadcast  from  the  Ren- 
dezvous only  once  a  week,  for  every  night 
as  a  regular  feature  of.  the  Chicago 
programs  of  the  Mooseheart  Station, 
Charley  Straight  and  his  famous  dance 
orchestra  will  contribute  to  the  enter- 
tainment. 

We'll  venture  to  say  that  if  you  have 
a  player  piano  and  will  walk  over  to  it 
now,  you  will  find  at  least  five  rolls  on 
your  shelves  bearing  the  signature  of 
Charley  Straight,  for  there  is  no  one  who 
has  played  piano  records  for  as  long  a 
time  as  has  Charley.  Now  is  marked  the 
inauguration  of  the  broadcasting  of  the 
last  of  the  really  popular,  big  and  famous 
dance  orchestras  of  Chicago. 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


41 


Hookup*8 


'THE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Reade 
■*■     contributed  by  our  readers.      It  is  a  department  wherein  our  readers  exchan 


ders"  in  RADIO  AGE,  is 
by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con 
tributors,  but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


THE  MAY  issue  of  RADIO  AGE! 
Gosh!  How  time  does  fly.  It  seems 
as  though  it  were  just  yesterday 
that  we  picked  up"the  September  issue, 
said  good-bye  to  Old  Man  Static  and 
prepared  for  a  Winter  of  ideal  reception. 
Now  we  must  prepare  for  a  Summer  of 
ideal  reception.  It  is  possible  and  it 
can  be  done,  although  it  has  not  been 
done  very  successfully  in  the  past. 

However,  developments  in  the  radio 
line  have  been  so  good  in  the  past  Winter, 
that  we  no  longer  fear  the  Summer  static, 
spoiling  all  our  good  DX  records  and 
pleasant  concerts,  popular  and  other- 
wise, from  out-of-town-stations.  When 
we  look  back  and  think  of  the  giant 
strides  made  by  radio  in  the  past  ten 
months,  I  am  sure  most  of  us  will  realize 
just  why  this  is  going  to  be  a  real  radio 
Summer. 

Take,  for  example,  the  super-hetero- 
dyne type  of  receiver,  with  its  extreme 
selectivity,  portability  and  last,  but  not 
least,  the  little  energy  collector  or  loop 
antenna,  that  they  use.  This  will  prac- 
tically eliminate  the  old  "distance  elim- 
inator"— static.  The  reason  for  this  is 
obvious  to  all  of  us.  In  the  past,  large, 
flat-topped  antennas  were  used,  and 
would  pick  up  disturbances  from  all 
directions.  The  loop  antenna  does  not 
do  this.  Consequently  most  of  the  un- 
desirable noises  will  not  get  through  to 
the  set,  to  be  amplified  many  times. 

One  must  not  necessarily  have  a  super- 
heterodyne to  operate  his  circuit  on  a 
loop.  Several  sets  employing  the  reflex 
principal  are  every  bit  as  efficient,  when 
using  a  loop  antenna,  as  well  as  when 
they  use  a  large  out-door  one.  Regenera- 
tive sets  can  be  made  to  operate  on  a 
loop  also.  In  our  blueprint  section 
several  months  back  one  of  these  was 
shown,  and  it  has  given  exceptionally 
fine  results.  It  consisted  of  a  detector 
tube  and  the  customary  two  stages  of 
audio  frequency  amplification.  And 
there  are  plenty  of  other  circuits  that 
will  work  just  as  well. 

Another'thing  that  comes  with  Spring. 
House-cleaning.  Don't  you  think  it 
might  be  well  for  us  to  house-clean  the 
radio  set  at  this  time?  Of  course,  it  will 
be  inconvenient  to  have  your  home 
itself  turned  upside  down  and  the  radio 
set  at  the  same  time,  but  it  has  to  be 
done,  and  there  is  no  time  like  the  pres- 
ent. Take  a  look  inside  the  cabinet, 
clean  out  the  dust,  tighten  up  on  the 
bolts  and  nuts,  test  the  soldered  connec- 
tions carefully,  and  tighten  up  on  the 
prong  connections  of  the  tube  sockets. 
Little  things  like  that  all  go  to  make  the 
set  work  better,  and  after  a  hard  Winter's 
service  on  the  part  of  the  radio  set,  I 
am  sure  it  will  be  appreciated  by  it!  It 
might  be  well  to  call  your  attention  to 
your  ground  connection,  which,  being 
usually  made  in  the  basement,  is  never 
looked     at.    This     might     have     become 


FELIX  FREDERIKSEN 
Delmar,  Iowa 


CONTRIBUTORS 

JOSEPH  LARSON 
Boise,  Idaho 


THOMAS  RODWAY 
London,  Eng 


City 
.  Winnipeg,  Man.,    Can. 
.Binghampton,  N.  Y. 
.  Wyandotte,  Mich. 


Can. 


Can. 


DIAL  TWISTERS 
Name  Address 

Ed.  Doughty 349  Armstrong  Ave.  - 

H.  E.  Potter 1  Hayden  St 

Edward  Lange 116  Eureka  Ave 

Clemente  Larranaga Box  82 E.  Pittsburgh,  Pa. 

Clarence  J.  Sneider ....1008  N.  Graham  St Milwaukee,  Wis. 

J.  M.  Kloss 3006  Courtland  Ave.... Oakland,  Calif. 

Dick  Ray ...1115  Ringwood  Place Clinton,  la. 

Roy  Studds,  Jr Takoma  Park,  Md. 

Robert  Drake _ 23  East  Spruce  St Elmwood    Place,    Ohio 

Don.  L.  Kooken Box  158 Garrett,  Ind. 

Harry  Schoy 5051  Pershing  Ave .Cleveland,  Ohio 

Geo.  D.  Walter R.  D.  No.  4 Easton,  Pa. 

Lyndon  Kirley 612  So.  Michigan  At So.  Bend,  Ind. 

Frank  Allen 1274  Glover  Ave Detroit,  Mich. 

Ed.  Haubner 689  Fifty  Eighth  St Milwaukee,  Wis. 

James  Squire 22  Drake  St .Montreal,  P.   Q. 

Lester  Briske — 1658  N.  Wisconsin  St Racine,  Wis. 

V.  H.  Miller... .....R.  F.  D.  No.  8 Greenville,  S.  C 

Frank  Barclay Metchosin,    Vic, 

B.  J.  Salsbury Otsego,  Mich. 

Jess  Edmondson Elm   Grove,    W.   Va. 

Bert  R.  Kissel 1447  Madison  Ave Covington,  Ky. 

C.  F.  Madison. 1567  Buenna  Ave Covington,  Ky. 

Paul  Wichert 125  Bostwick  Ave Jersey  City.N.  J. 

H.  L.  Remer _ Lakewood,  Ohio 

N.  B.  Winter 614  Oakwood  Ave .Columbus,  Ohio 

Ralph  E.  Riley 1711  Fifth  Ave Oakland,  Calif. 

Valdan    Baltz 120  Jefferson  Ave Wheeling,  W.  Va 

T.  F.  Fino Gary,  Ind. 

Robert  C.  Potter R.  R.  No.  3 Beamsville,  Ont.,  Can. 

Kenneth  Wyatt__ 54  East  St Fitchburg,  Mass. 

W.  Case 714  Shafer  Ave Saulte  Ste.  Marie,  Can. 

Hugh  M.  Clark .127  Winter  St Auburn,  Maine 

Robt.  E.  Blose..._ 1339  Chew  St Allentown,  Pa. 

D.  F.  Bullock 827  Weeden  St ..Pawtucket,  R.  I. 

Nicholas  G.   Hart Bienville,  Levis, 

Lewis  J.  Novak. 5446  Rohns  Ave Detroit,  Mich. 

Roy  Anderson ..R.  F.  D.  No.  2 Chanute,  Kans. 

William  Benter.. 304  Park  Ave Brooklyn,  N.  Y. 

J.  A.  Myers,  Jr 944  West  Capitol  St Jackson,  Miss. 

Arthur  W.  White No.  3  Winn  Park.. Woburn,  Mass. 

Arthur  J.  F.  Roth._ 634  N.  Law  St Allentown,  Pa. 

Howard  B.  Hopping— 325  Washington  St Muncie,  Ind- 

Bill  Schwarte..... 4648  No.  Kimball  Ave. ...Chicago,  111. 

Ambrose  Tobin ...3116  Woodlawn  Ave Valley,  Neb 


P.  Q. 


corroded  to  such  an  extent  that  you  are 
not  operating  with  a  direct  ground  at 
all.  Yes,  I  think  we  had  better  take  a 
look. 

I  am  going  to  ask  you  once  more  for 
information  on  portable  receivers.  Let 
us  have  the  benefit  of  your  experience. 


I  am  sure  that  some  of  our  thousands  of 
readers  could  give  us  some  very  beneficial 
"dope"  on  these  types  of  receiving  sets. 
So  don't  be  bashful.  Let  us  have  the 
results    of    your    experiments. 

Well — I    guess    that's    that,    for    this 
time,  and  trusting  that  you  will  continue 


42 


RADIO  AGE  for  May,  1925 


to  flood  this  department  with  your  DX 
lists  and  reports,  IiShall  let  you  go  on 
to  the  rest  of  this   department. 

THE   PICK-UPS  EDITOR. 

We  have  a  circuit  this  month  from 
Felix  Frederiksen,  of  Delmar,  Iowa.  It 
is  a  variation  of  the  well  known  "Ultra- 
Audion,"  and  Mr.  Frederiksen  says  it 
is  a  "bear"  for  DX  work.  This  circuit 
is  known  as  the  Woods  circuit,  and 
possesses  several  distinct  advantages 
over  the  ordinary   ultra-audion. 

It  is  very  sharp  in  tuning  and  for  that 
reason  is  capable  of  reaching  out  through 
heavy  interference  and  doing  real  DX 
work.  The  disadvantage  of  the  ordinary 
circuit  lies  in  the  fact  that  it  is  difficult 
to  control  the  amount  of  regeneration 
secured.  This  is  overcome  in  this  circuit 
by  the  use  of  a  plate  variometer  to  secure 
an  inductive  feedback  in  addition  to  the 
usual  connection  from  the  plate  of  the 
detector  tube  to  the  grid  circuit.  An 
additional  feature  is  the  use  of  a  vario- 
coupler  for  the  tuning  inductance.  By 
the  use  of  a  variocoupler  in  place  of  the 
tapped  coil  or  the  variometer  commonly 
used,  exceptional  selectivity  is  secured 
in  place  of  the  usual  broad  tuning  of  the 
single  circuit   receiver. 

Mr.  Frederiksen  advises  us  to  use  only 
the  best  parts  in  constructing  the  circuit. 
He  says:  "If  poor  parts  are  used,  do  not 
blame  the  circuit  if  it  does  not  come  up 
to  expectations."  This  advice  applies 
especially  to  the  variable  condenser, 
which  should  be  of  the  straight  line  wave- 
length curve  type.  A  twenty-three 
plate  one,  with  a  vernier  dial  attachment, 
is  what  you  will  need. 

The  aerial  binding  post  is  wired  to 
the  top  tap  of  the  vario-coupler  and  to 
one  of  the  switch  levers.  This  arrange- 
ment shorts  out  the  turns  of  wire  on  the 
top  half  of  the  variocoupler  that  are  not 
in  use  and  reduces  the  dead  end  losses, 
thus  increasing  the  efficiency  of  the 
coupler. 

In  place  of  the  variocoupler  you  can 
wind  a  fixed  inductance,  if  you  so  desire. 
On  a  bakelite  or  cardboard  tube  three 
inches  in  diameter  and  four  inches  long, 


wind  twenty-five  turns  of  No.  20  single 
cotton  covered  magnet  wire  on  one  end 
of  the  tube  for  the  primary.  Leave  a 
space  about  one-quarter  of  an  inch,  and 
wind  fifty  turns  in  the  same  direction 
on  the  other  end  of  the  tube  for  the 
secondary,  the  same  size  wire  being  used. 
This  inductance  can  then  be  mounted 
on  thin  strips  of  bakelite  for  supports 
and  a  very  good  substitute  is  obtained 
for  the  variocoupler.  The  variometer 
shown  can  be  eliminated  if  you  desire 
by  winding  a  rotor  on  a  small  wooden 
form  to  fit  inside  one  end  of  the  induc- 
tance coil  just  described.  It  (the  rotor) 
should  be  wound  with  seventy-five  turns 
of  No.  28  single  cotton  covered  wire. 

However,  we  think  it  would  be  best 
to  use  the  variocoupler  and  variometer. 

The  following  parts  will  be  necessary 
for  the  construction  of  this  circuit. 

1  vario-coupler. 

2  Switch  Levers. 

Switch  points,  determined  by  number 
of  taps  on  coupler. 

1   23-pIate  condenser. 

1   Fixed  grid  condenser,    .00025 

1   Variable    Grid   Leak. 

1    Variometer. 

1  Double  circuit  jack. 

1  Single  circuit  jack. 

1  Audio    frequency    transformer. 

1  Six  ohm  rheostat. 

1  Twenty  ohm  rheostat. 

Bolts,  nuts,  wire,  etc. 

Mr.  Frederiksen  seems  very  well 
pleased  with  this  type  of  set  and  those 
of  us  who  are  using  the  old  type  "singles" 
might  try  this  improvement  and  see 
what's  what.  We  have  not  quoted  Mr. 
Frederiksen's  letter,  as  it  was  quite  long, 
he  being  so  enthusiastic  about  his  set. 
His  DX  list  would  "drag"  most  of  us 
out  of  our  chairs.  It  certainly  is  a 
"whiz." 

So  for  the  benefit  of  all  conerned,  we 
are   going   to   pass   this   circuit   along. 

Mr.  Joseph  Larsen,  of  Boise,  Idaho, 
gives  us  a  suggestion  for  the  mounting 
of  spider-web  coils  behind  the  panel, 
which  we  think  might  prove  of  interest. 
His  letter  follows: 


The  Magazine  of  the  Hour 

RADIO    AGE, 

Chicago,  111. 
Gentlemen: 

Many  of  the  readers  of  the  Pick-ups 
and  Hook-ups  columns  no  doubt  have 
refrained  from  using  spider-web  coils, 
a  very  efficient  form  of  inductance,  due 
to  the  fact  that  mounting  them  in  the 
conventional  way  on  the  front  of  the 
panel,  makes  them  clumsy  and  unsightly. 
This  can  be  overcome,  however,  in  a 
very  simple  and  efficient  manner;  effi- 
cient because  of  the  possible  micrometer 
adjustment  and  the  absence  of  body 
capacity. 

The  drawing  explains  the  idea  so 
clearly  that  there  is  little  need  for  a 
detailed     description. 

The  wood  strips  to  which  the  coils 
are  fastened  are  cut  from  a  cigar  box. 
They  are  glued  to  the  inductance  and 
to  small  blocks  at  the  inside  of  the  panel, 
to  which  are  screwed  small  brass  hinges 
obtainable   from   any   hardware   store. 

The  brass  rods  threaded  into  the  knobs 
and  panel  may  be  any  convenient  size 
and  thread.  The  ends  against  the  hinges 
should  be  filed  round. 

If,  for  the  sake  of  appearance  of  dials, 
it  is  desired  to  separate  the  control  knobs 
farther  than  shown  in  the  sketch,  this 
is  easily  done  by  gluing  a  small  block  of 
empty  thread  spool  between  each  wooden 
arm  and  the  coil. 

Rubber  bands  supply  the  tension, 
tending  to  bring  the  coils  into  close  in- 
ductive relation.  By  adjusting  the  bands 
on  different  prongs,  the  tension  may  be 
varied. 

Honeycomb  coils  mounted  in  this 
manner  will  appeal  to  the  experimenter 
using  the  three  coil  tickler  regenerative 
circuit.  Very  efficient  oscillator-couplers 
for  the  super-heterodyne  can  also  be 
manufactured  in  this  manner.  For  the 
latter  I  suggest  a  form  having  an  odd 
number  of  spokes,  say  about  seventeen, 
with  a  beginning  or  minimum  diameter 
of  one  and  a  half  inches.  The  pick-up, 
secondary  and  tickler  coils  should  be 
wound  with  twenty-five,  thirty-five  and 
fifty  turns  of  wire,  respectively. 
Yours  very  trulv, 

Boise,  Idaho.       JOSEPH  LARSEN. 


£3  PLATE. 


'X/ 


l/VW 


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B- 


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I/WV 


bZZ+ 


A-0A+O-O     O      045+ 


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Circuit  contributed  by  Mr.  Frederiksen.     It  is  a  modified  form  oj  the   Ultra-Audion.    This  circuit  possesses  all  of  the  desirable 
qualities  of  the  "single"  plus  the  selectivity  of  the  three  circuit  tuner. 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


43 


It's  a  good  stunt,  Dial  Twisters,  and 
an  easy  one,  too.  Not  only  does  it 
keep  the  coils  out  of  sight,  but  it  protects 
them  from  dust  and  dirt,  preventing 
injury  to  them  at  the  same  time. 

Thanks,  Mr.  Larsen,  for  your  idea. 


A  letter  this  month  from  91  Hamilton 
Road,  Golden  Green,  London,  England, 
N.  W.,  as  follows: 

RADIO   AGE, 
Gentlemen: 

May  I,  from  the  other  side  of  the 
Atlantic,  contribute  my  quota  to  your 
very  interesting  journal?  It  is  always 
interesting  to  read  of  current  radio 
opinions  in  your  paper  and  it  gives  much 
information  as  to  the  trend  of  receiver 
design  on  your  side. 

In  the  attached  list  I  give  a  number 
of  stations  I  have  heard  on  my  present 
receiver,  which  consists  of  a  detector 
valve,  followed  by  one  stage  of  audio 
frequency  amplification.  Over  here, 
this  is  practically  the  standard  set. 
Very  few  experimenters  use  radio  fre- 
quency valves,  being  of  the  opinion  that 
it  complicates  tuning  and  really  only 
amplifies  the  "mush"  which  accompanies 
the  weak  signals.  The  only  uncommon 
thing  about  the  hook-up  enclosed  lies 
in  the  grid  return  lead. 

The  set  is  extremely  simple  to  make 
and  is  most  surprisingly  selective.  In 
fact,  the  local  station  2LO,  using  a  power 
of  one  and  one-half  K.  W.,  and  only 
five  miles  away,  is  completely  cut  out 
on  two  degrees  of  the  condenser.  It  is 
well  worth  a  trial  by  anyone  desiring 
extreme  selectivity,  together  with  full 
volume.  It  is  very  sensitive  to  weak 
signals,  as  the  enclosed  list  vouches  for. 
By  the  way,  do  you  think  it  will  merit 
a'D.  T.   Badge? 

Now,  I  am  going  to  ask  a  favor  of  you, 
or  some  of  the  readers  of  the  Pick-Ups 
and  Hook-Ups  section.  Will  somebody 
let  me  have  a  circuit  or  hook-up,  as  I 
believe  everyone  calls  them,  of  a  super- 
heterodyne, using  up  to  five  valves,  with 
the  audio  frequency  amplification  ob- 
tained by  a  reflex  arrangement?  I 
should  be  very  grateful  if  anyone  can 
do  this  for  me,  as  such  circuits  are  prac- 
tically impossible  to  obtain  in  England. 
Yours  very  truly, 
THOS.     RODWAY,    Jr., 

British  G-2ADG. 

We  are  printing  Tom's  letter  and  the 
diagram  of  the  circuit  that  he  says  most 
of  the  English  radio  fans  use.  L-l  is  the 
primary  and  consists  of  twelve  turns  of 
wire  wound  over  L-2,  the  secondary, 
which  consists  of  eighty-five  turns  of 
fairly  heavy  wire.  L-3  is  the  tickler  and 
consists  of  seventy  turns. 

As  can  be  seen,  this  circuit  is  one  of 
our  "old  time"  favorites,  and  gives  very 
good  results.  Below  you  will  find  the 
•  DX  list,  that  Tom  thinks  will  get  him 
a   DT  button: 

2L0.6BM,  5SC,  SIT,  2EH,  5PY,  2ZY, 
5NG,  2BD,  5NO,  Ecale  Supr,  Paris, 
"Petit  Parisien",  Radiola,  Eiffel  Tower, 
Radio  Electrique,  Brussells,  Radio  Iber- 
ica,  Madrid,  Berlin,  Frankfurt,  Ham- 
burg, Radio  Wien,  Vienna,  Bremen, 
WGY,  KDKA,  WBZ,  CKAC  and  WEAF. 

How  many  of  us  would  love  to  have 
our  log  read  like  that?  What  could  be 
sweeter?  But,  then,  I  suppose  perhaps 
Tom  should  like  to  have  our  KFIs  and 
KPOs,  on  his  log.  Anyway,  we  think 
it  is  just  fine  and  we  shall  ship  him  a 
DT  button,  "right  quick."  Is  it  all 
right,    fellows?      Absolutely,    Mr.  Kelly. 


Showing  method  of  mounting  honey-comb  or  spider-web  coils  behind  the  panel.      This 
is  quite  a  novel  idea,  contributed  by  Mr.  Larsen. 


Jos.  M.  Kloss,  of  Oakland,  Calif.,  has 
a  set  using  the  Roberts  circuit,  with 
which  he  is  "knocking  'em  dead." 
KDKA  was  heard  the  other  day  on  it, 
and  he  held  them  over  an  hour  and  a 
half.  This  is  pretty  good,  as  it  was  only 
5:30  p.  m.,  Pacific  Coast  time.  Some 
of  the  other  stations  that  he  nas  listened 
to  in  the  past  few  weeks  are  KFHR, 
CFCN,  KFNV,  KDYL,  KFSG,  CHBC, 
WOC,  WO  AW,  WIP,  KYW  and  KTHS. 
His  set  is  only  a  two  "tuber"  and  we 
think  this  is  pretty  good  work. 


scribed  in  the  March  issue  of  RADIO 
AGE.  I  have  tried  coils  of  all  sizes, 
shapes  and  forms  and  have  come  to  the 
conclusion  that  the  spider  web  form  of 
inductance  is  the  most  efficient.  Any 
of  the  readers  of  this  section  who  want 
'dope'  on  this  circuit  might  get  in  touch 
with     me." 

As  J.  A.  was  good  enough  to  offer  his 
services,  let's  see  that  some  of  us  mail 
him  a  card.  He  lives  at  944  W.  Capitol 
St.,  Jackson,   Miss. 


Howard  B.  Hooping,  Muncie,  Ind., 
is  doing  some  mighty  fine  DX  work  on 
his  "Hopwood"  set  built  according  to 
RADIO  AGE  specificaions.  Such  sta- 
tions as  KPO,  KGO,  KOA,  and  WQAM 
are  received  by  him  regularly.  He  also 
has  a  crystal  set  on  which  he  has  received 
KDKA' and    WGY. 


Arthur  J.  F.  Roth,  634  No.  Law  St., 
Allentown,  Pa.,  is  having  a  fine  time 
"pulling  in  the  long  ones"  on  his  three- 
circuit  outfit.  His  DX  list  runs  up  into 
the   "house"   numbers. 


We  have  a  letter  from  one  of  the  fans 
on  the  Eastern  Coast  who  is  uing  one 
of  RADIO  AGE's  latest  Reinartz  hook- 
ups, with  which  he  is  getting  wonderful 
results.  Any  of  you  fellows  who  are 
in  doubt  as  to  the  practicability  of  the 
Reinartz  circuit  might  drop  him  a  line 
and  get  his  opinion. 


T.  F  O'Connel,  from  "out  where  the 
West  begins"  wants  to  know  if  any  of 
us  have  ever  thought  of  using  a  breast 
drill  for  coil  or  radio  frequency  (long 
wave)  transformer  winding.  This  is  a 
good  stunt,  and  quite  a  few  of  the  "old 
timers"  use  it  all  the  time.  Nevertheless, 
we  are  going  to  pass  it  along  for  the 
benefit  of  the  newcomers  in  this  radio 
business.  Some  breast  drills  are  geared 
as  high  as  six  to  one,  and  you  can  easily 
see  that  your  work  is  reduced  fully  75 
per  cent  when  you  wind  by  this  method. 
All  you  have  to  do  is  to  fasten  the  form, 
or  core,  to  the  end  that  takes  the  drill. 
The  usual  method  is  to  insert  a  reamer 
a  trifle  larger  in  the  bit  than  in  the  hole. 
You  will  have  drilled  in  the  core  of  the 
transformer,  force  the  core  over  the  bit. 
fasten  the  starting  end  of  the  coil,  and 
"let  her  ride."  Try  it,  fans.  It  works 
very    well. 


J.  A.  Myers,  Jr.,  says:  "I  have  read 
the  article  on  the  two  tube  "Ultra- 
Audion"  and  I  would  like  to  say  for  the 
benefit  of  those  readers  who  are  interested 
that  I  have  done  quite  a  bit  of  experi- 
menting  with    the    Ultra-Audion    as   de- 


We  have  a  letter  from  Robert  E.  Blose, 
of  Allentown,  Pa.,  who  has  had  a  receiv- 
ing set  just  three  weeks,  and  has  a  list 
of  stations  heard  so  long  that  it  reads 
like  a  broadcasting  station  list.  To  print 
it  would  be  impossible,  so  we  will  have  to 
award  him  a  DT  button  without  dis- 
closing his   log.  (Turn  the  page) 


44 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hoar 


The  most  popular  type  of  receiving  circuil 
in  the  British  Isles,  One  of  our  readers  re- 
ports phenomenal  success  with  this  hook-up 


recommending    this    publication    in     no 
uncertain   terms. 

Thanking  you  again,  I  am 
Yours  very  truly, 

RALPH     E.     RILEY, 

1711    Fifth   Street, 

Oakland,     Calif. 

Letters  like  this  make  us  feel  real 
"chesty."  And  they  prove  conclusively 
that  our  slogan  is  correct:  "Let  Our 
Hook-Ups  be  Your  Guide." 


Hugh  M.  Clark  writes  us  to  let  us 
know  he  thinks  that  RADIO  AGE  is 
the  best  on  the  market.  He  has  a  Clapp- 
Eastman,  three-tube  regenerative  set, 
with  which  he  has  received  WSB,  PWX, 
KVVAQ,  KFOM,  CYL,  KOA,  KFKX, 
CFCN,  KSD,  WFAA,  KFRU,  KFI  and 
others  too  numerous  to  mention.  _  We 
call  this  pretty  good  reception,  consider- 
ing that  he  is  in  the  most  eastern  state 
in  the  union,  and  we  will  award  him  his 
DT  button.     He  lives  in  Auburn,  Maine. 


Kenneth  Wyatt,    54    Cast    St.,    Fitch- 
burg.,   Mass.,  writes  us  as  follows: 
RADIO  AGE, 

Chicago,    111., 
Gentlemen: 

Looking  over  back  issues  of  RADIO 
AGE,  I  noticed  a  record  made  with  a 
"Cockaday"  receiver,  of  thirteen  sta- 
tions in  thirty-nine  minutes.  Deciding 
to  beat  this,  I  sat  down  and  received 
twenty-nine  stations  in  thirty  minutes. 
Am  I  entitled  to  become  a  Dial  Twister? 
All  stations  were  heard  on  my  two  tube 
Cockaday. 

Yours  very  truly, 

KENNETH  WYATT. 

What  do  you  think,  fellows?  Pretty 
good.  Can  any  one  do  better?  We  shall 
see.  Meanwhile  this  will  stand  as  a 
record  and  Kenneth  will  be  awarded 
the  DT  button. 


merit  a  DT  button.  My  list  is  not  a 
very  long  one,  but  what  I  take  the  great- 
est pride  in  is  the  fact  thatl  can  get  these 
stations  at  will,  and  hold  them  as  long 
as  I  want  to  listen.  The  circuit  is  noth- 
ing phenomenal,  being  quite  common. 
Here  is  the  list:  WGR,  WBZ,  KDKA, 
WGY,  WEAF,  WNYC,  WCAE,  WFI, 
WSAI,  WLW,  WOC,  KYW,  KSD, 
WHAZ,  WMAK,  WJY,  WLS,  WAHG, 
CFCA,  WEBH,  WCBD,  WWJ,  WQJ, 
WHAS,  WEAR  and  KDKA. 
Yours   very   truly, 

ROBERT  C.   POTTER. 

R.  R.  No.  3, 

Beamsville,   Ont.,    Can. 

Your  list,  Bob,  as  you  say,  is  not  very 
long,  but  considering  the  fact  that  you 
receive  these  stations  at  will,  we  think 
it  is  a  very  good  one  and  will  award  you 
your  DT  button.  Also,  we  are  welcom- 
ing you  to  the   RADIO  AGE  family. 


Another  Interesting  Letter 

RADIO    AGE, 

Chicago,    111., 
Gentlemen: 

Glancing  over  a  copy  of  RADIO  AGE 
which  I  purchased  yesterday  for  the 
first  time,  I  noticed  your  "Pick-Ups 
and  Hook-Ups"  department,  which  in- 
terested me  very  much,  and  as  I  have 
done  some  rather  good  DX  work  myself, 
I  thought  I  should  like  to  see  if  it  would 


Valdan  Blatz,  of  Wheeling,  W.  Va., 
has  a  set  using  UV199  tubes,  with  which 
he  has  received  over  75  stations  in  the 
past  month.  He  wants  to  know  if  this 
will  admit  him  to  the  Dial  Twisters.  It 
certainly  will,  and  we  shall  send  him  his 
button  at  once.  His  circuit  is  the  regular 
old  "stand  by,"  the  three  ci»t:uit  outfit. 

Here  is  a  letter  from  an  ardent  booster 
of    RADIO    AGE. 
RADIO  AGE, 

Chicago,    111., 
Gentlemen: 

Just  completed  building  a  wave  trap 
from  a  diagram  published  in  the  RADIO 
AGE  ANNUAL  for  1925,  page  66, 
figure  4.  And  with  the  usual  RADIO 
AGE  reliability,  it  works  wonderfully 
well. 

RADIO  AGE  ANNUAL  is  worth 
many  times  the  purchase  price  to  any 
experimenter    and     I     take     pleasure    in 


Radio  Age,   Inc., 

Chicago,   111. 
Dear  Sirs: 

I  am  sending  herein  a  list  of  stations 
which  I  have  received  during  the  months 
of  November,  December  and  January. 
All  of  these  stations  were  received  on  a 
two  tube  Reinartz  Tuner,  using  peanut 
tubes.  This  set  has  given  loud  speaker 
volume  on  locals,  and  on  some  of  the 
distant  stations  the  announcer  can  be 
understood  with  the  phones  lying  on 
the  table.  Hoping  that  my  list  will  win 
a  Dial  Twister  Button,  I  remain, 
Yours    truly, 

JAMES  SQUIRE. 

22    Drake   St., 

Cote   St.    Paul, 

Montreal,  P.  Q. 

KDKA,  WBZ.  WTAS,  WIP.  WMAC,  WEAM,  WLAW. 
WDAP,  WWAD.  WAAF,  WGY,  WCBD.  WJAR,  WHAZ, 
WTAM,  KYW,  WFI,  WDAR,  1XAD,  WDAL,  WOS.  9XM' 
WDAE.  WBAY.  WJZ,  WDAF,  WCAL,  WABD,  WJAX. 
WSAJ,  WJAS.  WWJ,  WHN,  WREO,  WEBH,  GNKO, 
WCAP,  WIIAS.  WON,  WGR.  WOC,  WRC,  WSAI.  WQJ. 
WEAO,  KSD,  WEAR,  WHAR,  WLW.  CFCA. 


Quite  a  nice  list,  isn't  it,  fellows?  We 
think  he  well  deserves  a  Dial  Twister 
Button.  The  lads  up  in  Canada  all 
seem  to  have  ideal  reception. 


RADIO  AGE, 

Chicago,    111., 
Gentlemen: 

My  being  somewhat  of  an  experi- 
menter with  the  regenerative  principle 
has  resulted  in  a  modification  of  the 
so-called  three  circuit  arrangement  that 
really  does  what  I  consider  creditable 
work  considering  the  number  of  tubes 
used. 

And  having  built  and  tested  several 
of  these  modified  sets  and  found  the 
circuit  to  be  no  freak,  I  am  sending  in 
a  diagram  of  the  hookup  and  hope  you 
will  pass  it  on,  through  your  columns. 

Results  show  that  it  will  give  loud- 
speaker volume  on  two  tubes  for  a 
considerable  range,  and  in  selectivity 
I  think  I  may  safely  say  that  it  is  on  an 
equal  footing  with  any  neut  or  super- 
het,  when  using  a  short  antenna.  Rather 
strong,  that,  but — quite  true,  by  test. 

Along  with  the  hookup  I  am  sending 
a  list  of  stations  heard  on  each  of  two 
sets  using  this  hookup,  each  being  at 
different  locations.  I  only  give  the  most 
consistent  of  distant  stations  and  only 
a  few  of  the  nearer  ones,  as  they  are  too 
numerous  to  list  conveniently. 

Sot  No.  1.  two  tubes:  WREO.  WTAS,  KOA.  WSAI.  WLS, 
WDAF,  WEBH.  WTAM,  KHJ.  CFCA.  WLW.  KPO,  WCAE, 
KFI,  WFAA,  WOC,  KGW,  KYW.     Clara  A's  too  numerous. 

Set  No.  2.  one  tube:  KFON.  KFAB,  WABM,  WEEI, 
WMH.  KGO,  KOA,  WBZ,  CHYC,  KHJ.  PWX.  WHAS, 
CFCA.  WJY,  CKAC.  CKY,  KFI,  WOC,  CYL,  WCX. 
Class  A's  too  numerous. 

A  record  was  made  several  nights  ago 
when  45  stations  were  tuned  in  and 
identified  (on  one  tube)  within  3J^ 
hours,  the  total  combined  mileage  being 
37,000. 

I  am  a  constant  reader  of  RADIO 
AGE,    which    is   always   interesting. 

Hoping  for  a  DT  button, 

V.   H.  MILLER. 

R.  F.  D.,  No.  8,  Box  34. 

This  is  a  pretty  good  list,  and  will  give 
some  of  you   DT's  a  mark  to  shoot  at. 
Space    will    prohibit   our   publishing   the 
(Turn  to  page  56) 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour  45 


Lacault  Scores  Again/ 


.0005  mfd.  Capacity 


The  new  Ultra-Lowloss  condenser  is 
the  latest  improved  radio  device  de- 
signed by  R.  E.  Lacault,  formerly 
Associate  Editor  of  Radio  News,  the 
originator  of  Ultradyne  Receivers 
and  now  Chief  Engineer  of  Phenix 
Radio  Corporation. 


tlLTRH-VSRHISFi 

Tuning     control 

Simplifies  radio  tuning.  Pencil- 
record  a  station  on  the  dial — there- 
after, simply  turn  the  finder  to  your 
pencil  mark  to  get  that  station  in- 
stantly. Easy — quick  to  mount. 
Eliminates  fumbling,  guessing.  Fur- 
nished clockwise  or  anti-clockwise 
in  gold  or  silver  finish.  Gear  ratio 
20  to  1. 

Silver  $2.50        Gold  S3.50 


HLTRTHiGTDLOSS 

CONDENSER 

LIKE  every  Lacault  development,  this  new  Ultra-Lowloss 
Condenser  represents  the  pinnacle  of  ultra  efficiency — over- 
comes losses  usually  experienced  in  other  condensers. 

Special  design  and  cut  of  stator  plates  produces  a  straight  line 
frequency  curve,  separates  the  stations  of  various  wave  lengths 
evenly  over  the  dial  range,  making  close  tuning  positive  and  easy. 

With  one  station  of  known  frequency  located  on  the  dial,  other 
stations  separated  by  the  same  number  of  kilocycles  are  the  same 
number  of  degrees  apart  on  the  dial. 

In  the  Lacault  Ultra-Lowloss  Condenser  losses  are  reduced  to 
a  minimum  by  use  of  only  one  small  strip  of  insulation,  by  the 
small  amount  of  high  resistance  metal  in  the  field  and  frame,  and 
by  a  special  monoblock  mounting  of  fixed  and  movable  plates. 

At  your  dealer's,  otherwise  send  purchase 
price  and  you  <will  be  supplied  postpaid. 


Design  of  low  loss  coils  furnished  free  with  each  condenser  for  amateur 
and  broadcast  frequencies  showing  which  will  function  most  efficiently 
with  the  condenser. 


This  seal  on  a  radio  product  is  your 
assurance  of  satisfaction  and  guar- 
antee of  Lacault  design. 


To  Manufacturers  Who  Wish  to  Improve  Their  Sets 

The  Ultra-Lowloss  Condenser  offers  manufacturers  the  oppor- 
tunity to  greatly  improve  the  present  operation  of  their  receiving 
sets. 

Mr.  Lacault  will  gladly  consult  with  any  manufacturer  regard- 
ing the  application  of  this  condenser  to  any  circuit  for  obtaining 
maximum  efficiency. 


PHENIX  RADIO  CORPORATION,  116-B  EAST  25th  ST.,  NEW  YORK 


¥     Tested  and  Approved  by  RADIO  AGE     * 


45  RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


Standard  Radio  Receivers 

Last  month  RADIO  AGE  inaugurated  a  new  department  called  "  Knoic  Before 
You  Buy,"  to  serve  as  a  guide  to  the  prospective  radio  purchaser  in  deciding  on  the 
receiver  best  suited  to  his  individual  needs.  Fans  throughout  the  country  have  shown 
an  instantaneous  response  to  this  new  feature,  and  accordingly  it  is  continued  in 
this  issue  and  will  be  a  feature  of  all  forthcoming  numbers  of  RADIO  AGE.  Readers 
are  invited  to  write  us  concerning  the  sets  in  which  they  are  interested,  and  manu- 
facturers also  are  asked  to  send  us  material  describing  their  sets. 


Telmaco   Receiver    Useful    for 
Summer  Trips 

The  Telmaco  Acme  Type  P-l  Receiver,  shown  in 
the  photograph,  is  manufactured  by  the  Telephone 
Maintenance  Company  of  Chicago  and  contains 
some  new  features  in  portable  radio  construction 
that  will  undoubtedly  prove  popular  with  the  Sum- 
mer radio  fans  this  year. 

The  Telmaco  Acme  is  a  four-tube  reflex  receiver 
designed  to  assure  selectivity,  distance,  clarity  and 
volume,  with  minimum  battery  consumption,  even 
under  the  stress  of  Summer  conditions.  The  set 
retails  at  §125,  and  weighs  only  26  pounds  in  its 
complete  carrying  case  for  traveling.  The  loop  aerial 
and  loud  speaker  are  built  into  the  set.  The  loop 
is  the  only  aerial  needed. 

The  size  of  the  case  when  closed  is  8  inches  wide, 
10  inches  high  and  18  inches  long.  The  set  can  be 
put  into  operation  instantly  without  any  hooking 
up  other  than  that  already  contained  in  the  outfit. 
The  upper  portion  of  the  lid  is  lowered  when  the  set 
is  ready^to  be  operated. 


Records  of  Distance  and  Volume  with 
Howard  Set 


The  lettering  and  decorations  on  the  inside  of  the 
set  are  done  in  silver  tone  by  the  new  Telmaco 
Pyrogravure  process.  The  loop  is  contained  in  the 
walls  of  the  case,  being  concealed  from  view  and 
protected  from  mechanical  injury-  The  panel  is  so 
assembled  that  it  allows  instant  transfer  from  carry- 
ing case  to  a  mahogany  cabinet  made  by  the  Telmaco 
concern.  Likewise  the  mahogany  case  may  be  trans- 
ferred to  the  portable  arrangement. 

Three  stages  of  r.  f.  amplification,  three  stages  of 
audio  frequency  amplification  and  crystal  detector 
are  used.  Four  UV199  or  C299  tubes  are  used  with 
a  combined  B  battery  consumption  of  .24  amp. 

Practically  all  tuning  is  done  with  one  4-inch 
control. 

"Marwol  Baby  Grand"  is 
Ready  for  Vacations 

A  new  receiver  that  is  particularly  light  and  com- 
pact and  easily  convertible  into  a  portable  set  for 
Summer  use  has  been  placed  on  the  market  by  the 
Marwol  Radio  Corporation.  85  Mercer  street.  New 
York  City. 


This  is  known  as  the  "Manvol  Baby  Grand."  and 
comes  equipped  for  storage  battery  use,  but  may 
be  changed  to  operate  on  dry  cell  tubes. 

While  the  Manvol  Baby  Grand  is  much  smaller 
than  the  well  known  Manvol  Model  A-l,  it  contains 
identically  the  same  5-tube  tuned  radio  frequency 
circuit  that  is  known  for  selectivity,  range  and  ease 
of  operation.     The  Baby  Grand  retails  for  S40. 

A  loop  or  outside  aerial  may  be  used,  the  latter,  of 
course,  giving  the  best  distance.  The  Baby  Grand 
has  been  found  to  produce  results  similar  and  favor- 


The  Howard  5-tube  Neutrodyne,  made  by  the 
Howard  Radio  Company  of  Chicago,  has  been  de- 
veloped during  the  past  several  months  until  at 
present  it  is  a  highly  efficient  receiver  and  a  very 
popular  one  among  the  DX  fans. 

The  Howard  Neutrodyne  was  designed  primarily 
to  eliminate  annoyances  which  sometimes  exist  in 
radio  reception,  such  as  restricted  range,  howling, 
indistinct  reception,  and  interference  of  local  broad- 
casting stations. 

The  cabinet  of  this  improved  receiver  is  of  3-4  inch 
black  walnut,  high  polished.  It  is  fitted  with  a 
nickel-plated  hinge,  cover  stop,  and  felt  pads.  The 
entire  set  can  be  removed  from  the  cabinet  by  dis- 
connecting the  wires  from  the  nine  binding  posts, 
removing  two  machine  screws  from  the  bottom  of 
the  cabinet,  and  sliding  the  panel  upward  in  its  slots. 

Neutroformers,  which  are  radio  frequency  trans- 
formers especially  designed  for  Neutrodyne  use,  are 
wound  on  hard  rubber  tubing.  The  primary  winding 
is  invisible,  the  wires  resting  in  grooves  cut  in  the 
rubber  with  rigid  accuracy,  by  specially  constructed 
machines. 


Neutrodons,  variable  condensers  of  minute  ca- 
pacity between  plate  and  grid  in  the  tube,  are  easily 
adjusted  to  perfect  neutralization.  This  adjustment 
is  carried  out  at  the  factory  and  need  not  be  repeated 
To  attain  the  last  degree  of  clarity  in  sound,  three 
neutrodons  are  used  instead  of  the  customary 
two. 

Heavy  phospher  bronze  contact  arms,  spring  re- 
inforced, insure  contact  on  sides  of  the  tube  terminal 
pins  in  the  Howard  sockets,  giving  maximum  tube 
efficiency.  Panels  and  sub-panels  are  made  of  flaw- 
less Formica,  or  Bakelite,  no  wood  being  used  except 
in  the  enclosing  cabinet.  Wiring  is  squared 
bus- wire. 

The  Howard  set  is  designed  to  use  five  tubes,  all 
alike,  of  the  "A"  type.  It  operates  satisfactorily 
on  either  indoor  or  outdoor  antenna,  and  for  bringing 
in  coast  to  coast  stations  on  a  loud  speaker,  a  single 
outdoor  wire  fifty  feet  long  is  advisable.  The  Howard 
set  will  receive  with  uniform  efficiency  over  a  mini- 
mum range  of  190  to  610  meters. 

The  price  of  the  Howard  five-tube  Neutrodyne 
is  now  $200. 


ably  comparable  with  any  five-tube  receiver  of  the 
same  type.  It  was  designed  by  R.  H.  Martin,  general 
sales  manager  of  the  company,  to  eliminate  oscilla- 
tion over  the  entire  wave-length  range,  and  this  it 
can  be  said  to  accomplish  satisfactorily. 

The  Manvol  is  small  and  accordingly  is  easy  to 
carry  and  handle,  while  not  taking  up  much  room  if 
used  in  the  home  as  a  permanent  fixture.  The  Mar- 
wol people  decided  that  the  5-tube  tuned  radio 
frequency  type  of  receiver  was  the  best  suited  to 
portable  needs  and  likewise  one  of  the  most  popular 
circuits  of  the  day,  so  these  features  were  incorpor- 
ated when  the  new  Baby  Grand  was  designed. 

Operadio  Set  Entirely 
Self-Contained 

For  nearly  three  years  the  Operadio  Corporation 
of  Chicago  has  concentrated  on  one  model,  with  a 
view  to  obtaining  quality  of  tone,  greater  power  and 
range  and  loop  reception  and  big  battery  supply  in 
a  portable,  entirely  self-contained  unit. 

The  1925  Model  Operadio,  a  six  tube,  tuned  radio 
frequency  set.  with  six  "A"  batteries,  four  big  22  J4 
volt  B  batteries  and  a  built  in  loud  speaker,  is  par- 
ticularly interesting  in  its  design  to  obtain  reduction 
of  electrical  losses.  The  longest  wire  lead  is  2J^ 
inches.  The  tubes  are  supported  in  aluminum  con- 
tainers which  also  house  the  transformers,  grid  leaks, 
etc.,  impregnated  in  special  w^ax  to  eliminate  at- 
mospheric   variance. 

The  cover  serves  as  the  aerial  by  a  design  patented 
by  the  Operadio  Corporation. 

The  199  type  tube  is  used  throughout,  and  a  volt- 
meter operated  by  a  convenient  two-way  switch 
shows  the  operator  instantly  his  "A"  battery  draw 
or  his  "B"  batten-  resen^e.     Two  dials  tune  the  set 


through  special  condensers  of  Operadio  design  and 
make. 

These  condensers,  which  are  of  low  loss  design, 
have  an  eight-to-one  reduction  on  the  knob  and  back 
lash  is  eliminated  by  means  of  planetary  drive.  An 
exclusive  feature  is  a  fuse  on  the  "B"  batten'  circuit 
which  prevents  the  tubes'  burning  out.  The  tone 
of  the  Operadio  is  clear  and  undistorted.  and  dis- 
tance is  equal  to  many  eight-tube  sets.  All  long 
range  reception  can  be  had  on  the  loud  speaker. 
The  price,  complete,  is  now  5189.00. 

The  Operadio  can  be  used  as  an  ornamental 
decoration  to  the  home  or  it  may  be  carried  about 
easily. 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


47 


SMMMMMM^^^^MMI^MMmMMMMSMMMMMM^mMMMMMM^^MMM 


0  :^  0*6»" 


* 


-%no  Licensed  by        ,^\^a> 

SlK^er* Radio  MW^.V-S 

mEUTRODYNFi 

=  M !•>*£,,  27. 1923  and  *„'-,  ML' 

<»»"       Other  Patents  PenUinq'  B3-^s 


Howard 
Five  Tube  Neutrodyne 

To  build  the  best — the  ultimate — in 
radio  receiving  sets  regardless  of 
cost  has  always  been  our  ideal  and 
our  aim. 

That  we  have  succeeded  is  best  ev- 
idenced by  the  fact — not  what  we 
claim  but  what  an  actual  demon- 
stration will  prove  to  you. 

Hear  the  Howard  Five  Tube  Neu- 
trodyne  at  any  Howard  dealer  and 
then  decide. 


Howard  Manufacturing  Company,  Inc. 

451-469  East  Ohio  St.  Chicago 


ATTENTION 

Set  Manufacturers 

IF  YOU  ARE  INTERESTED 
IN  CUTTING  DOWN  YOUR 
PRODUCTION  COSTS  IT 
WILL  PAY  YOU  TO  COM- 
MUNICATE  WITH  US. 
YEARS  OF  EXPERIENCE 
HAVE  ENABLED  US  TO 
GIVE  MANUFACTURERS 
THE  BEST  POSSIBLE 
PRICES  CONSISTENT 
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48 


RADIO  AGE /or  May,  1925 


The  Fire 
Underwriters* 

Code  requires  that — 

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flyings  of  combustible  materials. 
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LISTEN  IN!    ~  " 
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to  1  a.  m.,  Saturday,  May  2. 

Radio  Age  at  WEBH,   11  to  12 

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The  Magazine  of  the  Hour 

A  New  Power  Supply 
Receiver 

{Continued  from  page  14) 


Parts  listed  are  given  under  headings 
that  indicate  their   use  in  the  receiver. 

"B"    Rectifier    System 

3  Audio  Freauency  Transformers 

2  Two  Mfds.  Fixed  Condensers 

2  Tube  Sockets 

1  Bell  Ringing  Transformer — 8  volt 

1  20  ohm  rheostat 

10  feet  flexible  rubber  covered  lamp  cord 

1  push  switch 

1  separable  plug 

Audio  Amplifier 

2  Audio  frequency  transformers 
2  tube  sockets 

1  .004  mfds.  fixed  condenser 

1  .0025  mfds.  fixed  condenser 

2  binding  posts 

Tuning    Circuits 
2  lengths  of  insulating  tubing, 3  inch  diameter,  3  inch  length 
1-2  lb.  No.  22  double  silk  covered  magnet  wire 

1  small   clip  connector  or  spring  clip  for  tap  adjustments 

2  binding  posts 
1  tube  socket 

1  double  mineral  crystal  detector 

2  .0005  mfds.  low-loss  variable  condensers 

Filament   Lighting 
1  8  volt  Bell  ringing  transformer 
1  "C"  battery 
1  potentiometer 
1  10  or  15  obm  rheostat 

Extra  Parts 
Aerial  and  ground  equipment 
Loud  speaker 

Bus  bar  or  No.  16  fixture  wire  for  set  connections 
Cabinet  and  baseboard  about  20  by  12  inche3 

The  circuit  diagram  is  laid  out  ap- 
proximately as  the  parts  are  to  be  placed 
on  the  baseboard,  and  further  suggestions 
may  be  had  from  the  photos.  The  "B" 
apparatus  should  be  compactly  mounted 
at  the  rear,  so  as  to  allow  plenty  of  room 
for  the  important  tuning  apparatus  at 
the  fore.  The  audio  amplifier  is  located 
along  the  left  edge  of  the  board,  starting 
at  the  front.  Two  binding  posts  are 
placed  at  the  rear  of  the  audio  amplifier 
for  the  speaker  and  two  others  at  the 
right  hand  rear  corner  for  aerial  and 
ground.  The  power  lead  is  brought  in 
at  the  rear  center  and  is  held  down  by 
a  simple  half-round  clamp  bent  from  a 
piece  of  iron  or  brass  and  fastened  with 
two  screws.  A  "U"  shaped  clamp  is 
bent  from  a  small  sheet  of  iron  or  brass 
as  a  clamp  to  hold  the  "C"  battery,  and 
another  clamp  of  smaller  size  made  to 
fasten  the  2  mfd.  condensers.  The  shape 
of  this  clamp  varies  according  to  the 
mak  of  condensers  chosen — these  being 
for  the  purpose  of  filtering  the  ripple 
out  of  the  rectified  "B"  voltage. 

Coil  Construction 

rTX)  TUNE  the  grid  of  the  R.  F.  tube 
J-  and  to  couple  it  to  the  aerial,  a  special 
coil  is  built,  40  turns  of  the  magnet  wire 
are  tightly  wound  on  one  of  the  lengths 
of  tubing,  taking  "twist"  taps  at  the 
5th,  8th,  11th,  15th,  20th,  25th,  30th 
and  35th  turns.  The  coil  ends  may  best 
be  connected  to  soldering  lugs  fastened 
at  the  edge  of  the  tubing  by  short  6-32 
machine  screws.  An  extra  screw  and  lug 
is  provided  at  one  end  for  the  antenna 
wire.  From  this  lug  a  short  piece  of 
flexible  wire  is  brought  to  a  clip  con- 
nector, whereby  contact  from  the  aerial 
may  be  made  to  any  one  of  the  taps 
provided.  The  taps  are  merely  twists  in 
the  wire,  scraped  as  the  winding  goes 
on  and  twisted  firmly.  Before  the  coil 
is  used,  these  are  soldered  for  greater 
strength   and   better  contact. 

Next,  a  coupler  is  made  for  coupling 
the  R.  F.  tube  to  the  crystal.  To  control 
the  sensitivity,  its  primary  is  made 
variable,   and,  most  any  coupler  on  the 


*     Tested  and  Approved  by  RADIO   AGE     * 


/ 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour         53 


vibration  is  at  one  moment  all  energy 
of  bending  and  at  the  next  all  energy 
of  motion. 

The  effect  of  the  impulses  is  cumula- 
tive. Each  increases  the  energy  of  vibra- 
tion by  a  little,  until  finally  the  vibra- 
tion is  large  enough  to  set  up  frictional 
resistances  which  use  up  all  the  further 
impulses.  Thus  the  small  impulses 
give  rise  to  enormous  forces,  but  these 
are  actually  supplied  by  the  elasticity 
and  mass  of  the  bridge.  The  bridge  in 
a  sense  breaks  itself. 

Each  Wave  Adds  to  Energy 

IN  A  similar  manner  the  weak  waves 
coming  to  a  receiving  antenna  set 
up  in  its  circuit  only  a  tiny  electromotive 
force,  far  too  small,  in  fact,  to  pass  the 
the  necessary  current  for  an  audible 
signal  through  either  condenser  or  coil 
alone.  If,  however,  the  circuit  is  properly 
tuned,  each  wave  adds  to  the  charge 
on  the  condenser  and  thus  to  the  current 
which  flows  in  the  circuit,  until  at  length 
it  is  so  great  as  to  requisition  all  the 
weak  electromotive  force  induced  in  the 
circuit  by  the  waves. 

The  circuit  then  oscillates  steadily, 
but  with  vastly  greater  electromotive 
forces  upon  the  coil  and  the  condenser 
than  the  tiny  voltage  directly  induced 
by  the  waves.  It  is  these  relatively  large 
electromotive  forces  which  are  analogous 
to  the  large  bending  force  and  the  force 
associated  with  the  momentum  of  the 
bridge  vibration.  It  is  these  large  elec- 
tromotive forces  which  overcome  the 
large  oppositions  of  condenser  and  coil 
to  the  passage  of  the  current.  Taken 
around  the  circuit,  they  are  nearly  equal 
and  opposite,  their  small  difference  being 
the  electromotive  force  induced  by  the 
waves,  but  the  detector  circuit  is  con- 
nected to  receive  their  full  effect. 

It  follows  from  these  considerations 
that,  if  we  could  make  the  resistance  of 
our  receiving  circuits  small  enough, 
waves,  however  weak,  could  produce 
appreciable  voltages  upon  the  detector. 

On  the  other  hand,  the  effect  of  waves 
for  which  the  receiving  circuit  is  not  in 
tune  is  to  alternately  aid  and  oppose 
the  natural  oscillations  of  the  receiving 
circuit,  with  the  result  that  very  little 
current  flows  and  the  detector  is  prac- 
tically unaffected. 

A  circuit  may  be  tuned  either  by  vary- 
ing the  capacity  of  its  condenser  (elas- 
ticity of  the  circuit)  or  by  the  varying 
its  inductance  (electrical  mass  of  the 
circuit),  and  it  is  immaterial  which, 
just  as  it  is  possible  for  a  violinist  to  tune 
a  string  either  by  changing  its  tension 
or  the   length   of  the   vibrating  portion. 

In  conclusion,  when  you  see  your 
long  distance  radio  friend  silently  turning 
a  dial  with  a  distraught  air,  you  may 
feel  sure  that  his  anxious  face  does  not 
indicate  that  he  is  afraid  of  losing  a 
single  word  of  the  speaker.  He  is  merely 
absorbed  by  the  delicate  task  of  so  ad- 
justing the  electrical  stiffness  or  elec- 
trical mass  of  his  receiving  circuits  that 
they  will  allow  the  maximum  current 
to  flow  and  thus  set  up  the  greatest  possi- 
ble voltage  across  condenser,  coil  and 
grid. 


KEEP  reception  clear/ 


The  Tungar  is  a  G-E 
product,  developed  in 
the  great  Research 
Laboratories  of  Gen- 
eral Electric. 

The  New  Model  Tun- 
gar charges  radio  A 
and  B  storage  bat- 
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size  (East  of  the 
Rockies)    .    .    .   $18.00 

A  Tungar  is  also 
available  in  five  am- 
pere size,  design  un- 
changed (East  of  the 
Rockies)  $28.00 

60  cycles— 110  volts 


* 


Keep  it  clear.  Keep  it  loud — with  all  the  vol- 
ume your  set  should  have.  Keep  the  battery 
at  top  notch — fully  charged — peppy. 

The  Tungar  charges  your  storage  battery  over- 
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a  switch.  Keep  your  set  at  its  best  all  the  time 
— with  a  Tungar. 

Tungar 

Reg.  U.  S.       M|  Sg&.         PAT.  OFF. 

[BATTERY   CHARGERj 


1'ungar — a  registered  trademark — is  found  only 
on  the  genuine.    Look  for  it  on  the  name  plate. 

Merchandise  Division 
General  Electric  Company,  Bridgeport,  Conn. 


GENERAL  ELECTRIC 


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123  W.  Madison  St.  Chicago 


Henninger  Aero-Coils 

Give  more  Volume  and  Sharper 
Tuning 

The  true  Iow-1oss'radactance.E95% 
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1772  Wilson  Ave., Dept.     32 Chicago 


If  Your  Neut's  Gone  Back  On  You — 

Rebuild  it  to  this  Kladag  Coast  to  Coast  Circuit,  using 
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Over  a  thousand  "converted"  Neuts  are  daily  bringing 
in  clean  resonant  volume  from  Coast  to  Coast.  Details 
—10c.  48-page  meaty  catalog  of  PARTS  ONLY— 10c. 
Kladag  Radio  Laboratories,  Kent,  Ohio 


#     Tested  and  Approved  by  RADIO  AGE     # 


54 


RADIO  AGE  for  May,  1925 


CSjL^^m-JL    h^rvv     &&C-.     <?.  S.  T. 

450v  EDISON  BATTERY  in  five  sections,  complete  -with 
magnetic  rectifier,  sell  $100.00  or  consider  exchange  deal 
for   1000-1500   v   DC    110   v   AC  motor-generator.   ESCO. 


pjeferred.  also  have  New  rotary  gap  with  llOv  Univers 
tnotor  $7700,  10.000  v  open  core  transformer,  $15.00  .01 
glass  plate  condenser  $3.00.  G.  Arnold  Edwards,  clAW, 
North  Sydney,  N.  S..  Canada. 


/v*~- 


UV-TXA^L  . 


A  SMALL   PORTABLE   SET  FOR  THE   AUTO,   BOAT  OR  HUNTING  LODGE., 

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Requires  a  minimum  of  technical  knowledge  to  effectively  operate. 

This  but  one  of  over  200  combinations  listed  in  Bulletin  No.  237B. 
Write  for  your  copy  today. 

ELECTRIC  SPECIALTY  COMPANY 

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4-25 


The  Magazine  of  the  Hour 

Some  Radio  Programs  and 
Personalities 

(Continued  front  page  30) 
Russell,  Jimmy  Kessell,  Leonard  Van 
Berg,  Virginia  Flohri  or  the  Packard 
Six  Orchestra,  it  will  be  seen  that  prac- 
tically none  of  them  can  be  granted. 
Yet  the  public  seems  to  sense  the  willing- 
ness on  the  part  of  the  station  and  the 
artists  to  co-operate  in  giving  the  public 
what  it  wants,  as  the  requests  increase 
week  by  week. 

During  the  mysterious  Double  Voiced 
Octavos'  first  programs,  the  main  studio 
of  KFI  was  called  from  over  600  miles 
away.  During  the  fifteen  minute,  one- 
act  play  given  on  Hallowe'en,  a  dozen 
long  distance  calls  were  made  from  out- 
lying points  in  Southern  California. 
Anything  that  arouses  curiosity  will 
produce   telephone  calls. 

Many  long  lost  friends  have  been 
brought  together  over  the  telephone  at 
KFI.  A  singer's  name  will  be  announced, 
then  someone  who  has  known  someone 
of  that  name  will  call  in  and  hesitatingly 
ask  if  "Sophie  Klotz,  who  just  sang 
'Sweetest  Little'  Feller' — did  she  ever 
live  maybe,  in  Oklahoma  City  about 
ten,  twelve  years  ago?"  Sometimes  it 
is  a  different  Sophie,  but  just  as  often 
it  is  the  right  one  and  then  KFI  is 
thanked  with  a  box  of  oranges  or  a  pair  of 
bed-room  slippers  orsomethingof  the  kind. 

The  hostess  at  KFI,  who  happens 
to  be  the  writer  of  this  story,  is  con- 
vinced that  the  perfect  hostess  at  a 
broadcasting  station  should  have  an 
Encyclopaedia  Britannica  and  a  reference 
library  at  her  elbow  to  be  able  to  take 
care  of  the  various  questions  that  are 
asked  on  anv  one  night. 

STATEMENT  OF  THE  OWNERSHIP,  MANAGEMENT, 

CIRCULATION,     ETC..     REQUIRED     BY 

THE  ACT  OF  CONGRESS  OF 

AUGUST  24,  1912. 

Of  Radio  Age,  published  monthly  at  Mount  Morris,  Illinois. 

for  April  1,  1925. 

State  of  Illinois,  County  of  Cook,  ss. 

Before  me,  a  Notary  Public  in  and  for  the  State  and  county 
aforesaid,  personally  appeared  M.  B.  Smith,  -who,  having  been 
duly  sworn  according  to  law,  deposes  and  says  that  he  is  the 
Business  Manager  of  Radio  Age  and  that  the  following  is.  to 
the  best  of  his  knowledge  and  belief,  a  true  statement  of  the 
ownership,  management  (and.  if  a  daily  paper,  the  circula- 
tion), etc.,  of  the  aforesaid  publication  for  the  date  shown  in 
the  abo-e  caption,  required  by  the  Act  of  August  24,  1912, 
embodied  in  section  443,  Postal  Laws  and  Regulations, 
printed  on  the  reverse  of  this  form,  to-wit: 

1.  That  the  names  and  addresses  of  the  publisher,  editor, 
managing  editor,  and  business  m°nagers  are:  Publisher, 
Radio  Age,  Inc..  Chicago,  III.;  Editor,  Frederick  Smith, 
Chicago,  111.;  Managing  Editor,  Froderick  Smith,  Chicago. 
III.;  Business  Manager,  M.  B.  Smith.   Chicago.  111. 

2.  That  the  owner  is:  (If  the  publication  is  owned  by  an 
individual,  his  name  and  address,  or  if  owned  by  more  than 
one  individual,  the  name  and  address  of  each,  should  be  given 
below;  if  the  publication  is  owned  by  a  corporation  the  name 
of  the  corporation  and  the  names  and  addresses  of  the  stock- 
holders owning  or  holding  one  per  cent  or  more  of  the  total 
amount  of  .stock  should  lie  given).  Radio  Age,  Inc.,  Chicago, 
PI.,  Frederick  Smith,  500  N.  Dearborn  St.,  Chicago.  111.. 
President;  M.  B.  Smith,  Secretary  and  Treasurer,  500  N. 
Dearborn  St.,  Chicago.  III.;  John  H.  Lohbeck.  Vice-President 
6429  Cates  Ave..  St.  Louis,  Mo. 

3.  That  the  known  bondholders,  mortgagees,  and  other 
security  holders  owning  or  holding  1  per  cent  or  more  of  total 
amount  of  bonds,  mortgages,  or  other  securities  are:  (If 
there  are  none,  so  state).      None, 

4.  That  the  two  paragraphs  next  above  giving  the  names 
of  the  owners,  stockholders,  and  security  holders,  if  sny, 
contain  no;;  only  the  list  of  stockholders  and  security  holders 
as  they  appear  upon  the  books  of  the  company,  but  also,  in 
cases  where  the  stockholder  or  security  holder  appears  upon 
the  books  of  the  company  as  trustee  or  in  any  other  fiduciary 
relation,  the  name  of  the  person  or  corporation  for  whom 
such  trustee  is  acting,  is  given;  also  that  the  said  two  para- 
graphs contain  statements  embracing  affiant's  full  knowledge 
and  belief  as  to  the  t-irciimstiincr-s  and  conditions  under  which 
stockholders  and  security  holders  who  do  not  appear  upon 
the  books  of  the  company  as  trustees,  hold  stock  and  securi- 
ties in  a  capacity  other  than  that  of  a  bona  fide  owner;  and 

to  be.ieve  that  any  person,  associa- 
any  interest  direct  or  indirect,  in 
other  securities  than  as  so  stated 

imber  of  copies  of  each  Issue  of  this 
publication  sold  or  distributed,  through  the  mails  or  other- 
wise, to  paid  subscribers  during  the  six  months  preceding  the 
date  shown  above  is:  (This  information  is  required  from 
daily  publications  only). 

M.   B.   SMITH. 
Business  Manager. 
Sworn  to  and  subscribed  before  me  this   1st  day  of  April, 


this  affiant  has 
tion,  or  corporation  1 
the  said  stock,  bonds 
by  him. 

That  the 


FLORENCE  A.  SMITH, 
expires  Sept.  21,  1926). 


#     Tested  and  Approved  by  RADIO  AGE     # 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


WNAC— The  Popular 
Women's  Station 

(Continued  from  page  25) 

prophesied  the  future  in  hatdom.  And  it 
must  be  remembered  that  this  show  was 
the  real  thing;  in  other  words,  inside  stuff. 
Only  milliners  were  allowed  admittance, 
even  though  any  American  house-wife 
could  hear  the  entire  proceedings. 

As  the  many  beautiful  models  came 
down  the  run-way  to  the  music  of  one 
of  Boston's  smart  orchestras,  Jean  Sargent 
gave  a  remarkable  word  picture  of  each, 
describing  the  gowns  in  careful  detail. 
And  the  men  did  not  regret  listening  in  on 
this  colorful  feature — even  if  the  color 
could  only  be  seen  by  proxy.  For  when 
one  heard  the  announcer  say:  "And  here 
comes  a  very  beautiful  girl  with  a  stright- 
line  gown  of  lip-stick  hue,  wearing  a 
directoire  hat  of  dull  garnet  satin,"  or, 
"There  is  a  cute  little  blonde-haired  lady 
making  her  entrance  as  the  orchestra 
plays  'Blue-Eyed  Sally;'  she  is  wearing 
a  gown  of  blue  charmeuse  edged  with  old 
silver  and  her  hat  is  one  of  the  new  large 
designs  in  color  to  match;  very  chic!" 
Whose  imagination  would  not  flutter  after 
all  that  vivid  description? 

This  millinery  show  was  referred  to 
above  as  the  crowning  triumph  of  the 
women's  section  of  WNAC,  but  anyone 
who  knows  Jean  Sargent  knows  that  she 
will  not  be  content  to  rest  upon  her 
laurels.  Take  for  instance,  this  statement 
made  several  weeks  before  the  millinery 
show,  in  the  home-like  atmosphere  of  one 
of  the  station  studios: 

"Within  the  next  few  months,"  she 
said,  "I  am  planning  to  give  the  women 
more  and  more;  for,  after  all,  the  women 
are  becoming  just  as  ardent  in  this  radio 
game  as  the  men.  For  instance,  after 
putting  on  a  special  program  of  any 
variety,  we  usually  find  women  to  be 
more  responsive  than  men.  A  woman  is 
quicker  to  critise  than  a  man,  and  criti- 
cism is  essential  in  the  life  of  any  first- 
class  radio  station." 

WNAC  is  a  progressive  station,  and 
its  sponsor,  John  Shepard,  Jr.,  is  an  idol 
in  many  of  the  hearts  of  New  England 
radio  fans.  Frequently,  the  programs  for 
women  are  relayed  from  the  Boston  sta- 
tion through  the  Providence  station  of 
the  same  company,  WEAN. 

And  as  the  genial  and  highly  popular 
director  of  WNAC,  Major  John  J.  Fan- 
ning, says:  "The  'W  in  both  cases 
might  stand  for  'woman'." 


STATIC— THE   RADIO 
BUGBEAR 

How  can  it  be  best  elimi- 
nated, or  at  least  minimized  to 
an  unnoticeable  degree?  Ros- 
coe  Bundy,  that  famous  radio 
analyst,  has  prepared  an  article 
on  "Static"  that  will  do  away 
with  the  old  fear  of  Summer 
reception.  Look  for  it  in  the 
June  RADIO  AGE— out  May 
15th. 


RADIO 


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56 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


Finer  Selectivity  j 

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(Signed) 
W.E.Wiltse. 


How  to  Make  a  Vacuum 
Tube  Tester 

(Continued  from  page  12) 
been   bolted  down  as  tight  as  is  safely 
possible. 

A  poor  connection  will  add  resistance 
to  the  circuit  and  may  result  in  throwing 
the  readings  of  the  meters  off  quite  a  bit. 

We  will  now  turn  to  the  wiring  diagram 
and  run  the  leads  as  indicated  in  the 
table  on  page  11.  The  pane]  will  then  be 
marked  as  desired  and  mounted  in  its 
cabinet  or  placed  in  its  permanent  loca- 
tion. Simple,  isn't  it?  Only  25  leads  to 
run.  To  connect  the  instrument  for 
operation,  the  batteries  will  be  connected 
as  follows: 

"B"  or  Plate  Battery 

Connect  90V  of  "B"  grid  battery  from 
bindingposts  B  — toB90,takingtapsoff  at 
llYz  volts,  45  volts  and  67  y%  volts,  and 
connecting  them  to  their  respective 
binding  posts  B  22  Y2,  B45  and  B  67  Y2. 
"A"  or  Filament  Battery 

Connect  a  1H.  3  or  6  volt  battery 
across  binding  posts  A—  and  A+,  the 
size  to  be  according  to  the  tube  under 
test. 

"C"    or    Grid    Battery 

Connect  two  4V£  Volt  C  batteries  in  series 

and  across  binding  posts  C+  and  C— , 

taking  a  tap  between  the  two  batteries 

and  connect  it  to  binding  post  C4 — . 

Method  of  Operation 

TO  TEST  a  tube  or  plot  a  curve, 
there  are  several  characteristics  about 
a  tube  that  can  be  put  to  good  use, 
when  known.  They  can  be  found  by 
using  this  tube  tester.  Let  us  take  a 
Number  199  type  tube  and  plot  a  grid 
potential  and  plate  current  curve,  foi 
example. 

When  the  batteries  are  all  connected, 
put  the  tube  into  the  socket  (T)  using 
the  adapter.  First  move  the  switch 
(BS)  to  the  negative  point,  then  move 
the  switch  PS  to  the  45  volt  tap.  Now 
set  the  transfer  switch  (TS)  for  the 
0-10  volt  scale  on  the  meter  (PF.)  Move 
the  rheostat  (R)  until  the  meter  shows 
3  volts. 

Adjust  the  potentiometer  (GP)  until 
the  meter  (GM)  shows  "0."  Now 
throw  the  transfer  switch  (TS)  for  the 
0-100  scale  on  meter  (PF),  and  adjust 
the  rheostat  (BR)  until  a  45  volt  reading 
is  obtained.  Then  cut  out  meter  (GM) 
by  use  of  the  switch  (GS)  and  move 
the  resistance  (R)  until  the  highest 
reading  is  obtained  on  the  milliammeter 
(MA).  This  will  be  the  normal  plate 
current  of  the  tube,  at  45  volts  on  the 
plate  with  a  grid  bias  of  "0"  volts,  and 
whatever  filament  voltage  the  meter 
(PF)   will  show. 

To  plot  a  plate  current  curve  (See 
Figures  3  and  4),  move  your  switch 
(PS)  to  the  22  ]/i  volt  tap  and  adjust 
your  resistance  (BR)  until  the  volt- 
meter (PF)  reads  20  volts.  Adjust  the 
filament  rheostat  (R)  until  the  maximum 
reading  is  obtained  on  the  milliammeter 
and  spot  this  reading  as  shown  on  the 
chart.  Now  adjust  your  switch  (PS) 
and  your  rheostat  (BR)  until  the  meter 
(PF)  shows  25  volts,  and  spot  the  reading 
%■     Tested  and  Approved  by  RADIO  AGE     * 


of  the  meter  (MA),  repeating  this  opera- 
tion in  steps  of  5  volts  until  you  cover 
the  desired  range.  Connect  these  points 
on  the  chart  with  a  line  and  you  will 
have  a  plate  current  chart  at  a  "0" 
volt  grid  bias. 

To  plot  a  plate  curve  at  various  grid 
voltages,  and  for  positive  and  negative 
grid  biasing,  move  the  switch  (BS)  to 
the  positive  or  negative  point  and  adjust 
the  potentiometer  (GP)  until  the  desired 
grid  voltage  shows  on  the  meter  (GM). 

Always  cut  the  meter  (GM)  out  of  the 
circuit  by  use  of  the  switch  (GS)  when 
reading  the  plate  current  on  the  meter 
(MA).  A  grid  voltage  curve  for  various 
plate  currents  and  voltages  will  be  made 
in  the  same  manner,  except  by  taking 
periodic  readings  from  meter  (GM), 
say  about  one-half  volt  apart  and  plotting 
the  curve  the  same  way. 

Formulas  and  other  data  for  testing 
and  plotting  curves  will  be  published 
in  an  early  issue  of  RADIO  AGE,  with 
a  view  to  covering  as  much  about  tube 
characteristics  as  is  useful  to  the  fan. 
Tables  for  average  computation  will 
also  be  shown. 


Pickups 

By  Our  Readers 

(Continued  from  page  44) 

circuit  used  by  Mr.  Miller,  which  is  a 
variation  of  the  three  circuit  principle. 
Any  of  you  who  are  interested  might 
drop  him  a  line  and  get  the  desired  in- 
formation direct  from  him.  Anyway, 
we  are  going  to  award  him  a  DT  degree 
for  the  splendid  results  he  is  having  as 
a  result  of  exhaustive  experiment. 


RADIO  AGE, 

Gentlemen: 

I  am  a  reader  of  RADIO  AGE  and  I 
have  learned  many  a  thing  from  your 
magazine.  I  know  the  fans  are  after 
circuits  that  are  simple  and  powerful 
and  this  sure  will  bring  in  DX  as  clear 
as  a  bell.  This  is  Capacity  Feed  back 
circuit  and  here  is  a  record  of  DX  Satur- 
day evening  from  10  p.  m.  until  12  mid- 
night at  my  friend's  home  in  Woodhaven, 
L.  I.,  Jerome  Kupfer,  8411  94th  Street. 

KDKA,  KYW,  KFI,  WSAI,  KSD, 
PWX,  HAVANA,  WHAS,  WOO,  WIP, 
WTAM,  WGAM,  WWJ,  WGR,  and 
WREO. 

These  were  all  heard  on  a  loud  speaker 
all  over  the  house  and  clear.  If  any  of 
you  fans  can  show  me  something  better, 
well,  go  to  it,  boys,  I  am  on  the  job  to 
learn  any  time.  If  you  will  write  to  me 
I  will  gladly  join  you  working  out  cir- 
cuits with  my  favorite  RADIO  AGE 
Magazine. 

Yours  very  truly, 

William  Bentner. 

304    Park   Ave., 

Brooklyn,   N.  Y. 

Here  is  a  good  offer,  fellows.  Any  of 
you  who  want  information  on  circuits 
of  this  type  should  get  in  touch  with 
"Bill."  The  circuit  he  describes  we  are 
unable  to  print  this  month,  but  will  use 
it  in  the  near  future.  It  must  be  very 
efficient,  judging  from  his  DX  log  and 
the  offer  he  makes. 

(Turn  to  next  page) 


RADIO  AGE  for  May,  1925 

RADIO    AGE,    Inc., 

Chicago,   111. 
Dear    Sirs: 

Herewith  find  list  of  broadcasting 
stations  picked  up  on  a  one  tube  radio 
set  on  the  evening  of  February  21,  1925. 

I  hope  that  this  will  entitle  me  to 
become  a  Dial  Twister  and  in  anticipa- 
tion of  receiving  your  button  by  return 
mail, 

I    remain, 

Yours  very  truly, 

Nicholas   G.    Hart. 

Bienville, 

Levis,  P.  Q. 

Here  is  his  list,  and  we  think  it  is  one 
of  the  best  ever  submitted  to  these 
columns,   considering   distance. 

KVW.  CKAC.  WREO.  WEAF.  WEBH.  WGN\  WTAM. 
WSAI.  WBZ.  WGY.  KDKA.  WCAL.  WI/W,  WTAS.  WQJ. 
WPBH,  CFCA.  CNR0. 

As  "Sen"  Kaney  of  KYW  would  say, 
"Yes  Sir,  Yes  Sir,"  indeed,  you  do  get 
your   D.   T.   button. 


The  Magazine  of  the  Hour 


RADIO  AGE, 
Gentlemen: 

I  am  sending  a  list  of  stations  that  I 
received  on  a  two  tube  home  made 
Harkness.  I  am  located  a  half  a  square 
from  a  transforming  electric  station  and 
have  a  lot  of  interference.  I  hope  that 
this  list  entitles  me  to  a  DIAL  TWIST- 
ER'S   button. 

KYW.  KDKA.  KFXF.  KFGZ.  KFDM.  KFIX  KFKB. 
KFKX,  KSD.  PWX.  WJY.  WBZ.  WLW.  WSA1.  WCAP. 
WMH.  WDAF.  WGY.  WTAM.  WHAZ.  WJAR,  WCBD. 
WEEI.  WGX,  WGBS.  WOR.  WHX.  WHAS.  WRK.  WOC. 
WE.AF,  WEBH.  "WOS.  WJAX.  WBAV.  WRE0.  WQJ. 
WCCO,  WTAS.  WGR.  WJJD.  WLS.  W0AW.  WWJ.  WHO. 
WMAZ,  WFAA.  WHB.  WOQ.  WHA.  WMC.  WEAN.  WJAS. 
WCBO,  WNAC,  WSBI,  WAHG.  WHAM,  WCAD,  WGAX. 
WEAI.  WOAI.  WOI.  WBCN-,  WJAD.  WDAR,  WCK. 
WBBR.  WBBL.  WHK.  WTC.  WCBR,  WWAE.  WTAY. 
K0P. 

Yours  very  truly, 

Robert    Drake. 
23   East  Spruce  St., 
Elmwood  Place,   Ohio. 
This  is  a  very  fine  DX  list,  and  we  are 
sure  that  you  will  agree  with  us  in  award- 
ing  Bob  his   D.  T.   Button.      He    must 
have  sat  up  "plenty"  nights  to  get  such 
a   fine   record   together. 


WARM -WEATHER    SUR- 
PRISES FOR  RADIO 
AGE  FANS  ! 

As  warm  weather  and  Summer 
approach,  there  will  be  no  let-up 
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there  will  be  countless  agreeable 
surprises,   among  which  will  be: 

"Outdoors  with  Radio,"  by  Arm- 
strong Perry. 

"Getting  Rid  of  Static,"  by 
Roscoe   Bundy. 

"A  Portable  Super-Heterodyne," 
by  H.  Frank  Hopkins. 

The  Browning-Drake   Circuit. 

More  About  the  Double  Grid 
Tube   and   Its   Circuits. 

How  to  Make  This  a  Radio 
Summer. 

A  Big  Pickups  Section — 

And     Many     Other     Features. 
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Don't   forget    to    send    your  DX 
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THE  PICKUPS  EDITOR 


Better  Than  a 
Laboratory  Standard 

The  usual  method  of  measuring  condenser  resistances  is  by 
comparison  of  readings  obtained  when  the  condenser  to  be  meas- 
ured is  interchanged  with  a  precision,  laboratory  "standard" 
in  the  same  circuit. 

Professor  G.  M.  Wilcox,  of  Armour  Institute  of  Technology, 
recently  conducted  tests  on  two  B-T  Lifetime  Condensers  taken 
from  stock  and  found  they  were  of  lower  resistance  than  his 
laboratory  standard. 

Part  of  Professor  Wilcox's  letter  reads  as  follows: 

"When  the  B-T  Condensers  were  in  the  circuit  the  current 
was  1  to  2  per  cent  greater  than  that  obtained  with  the  Labo- 
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Condensers,  "Better  than  Laboratory  Standard,"  are  repre- 
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Such  apparatus  in  combination  with  a  specially  designed 
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58 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


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Maximum  Miles  Per  Watt  with 
This  Transmitter 


/ 

/ 

©© 
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0         I 

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4 

Pi*,/   WP» 

« 

A  n  Esco  Item  A'o.  33  Motor 
Generator  is  employed  as  the 
source  of  power  in  this  trans- 
mitter of  the  20-watl  type.  A 
transmitter  like  this  empolys 
the  well-known  3-coil  Meissner 
circuit  and  gives  remarkable 
distance  for  its  size. 


TO  THE  man  who  has  a  limited 
amount  of  capital  to  invest  and  wants 
to  obtain  the  maximum  miles  per  dollar, 
which  is  essentially  the  maximum  miles 
per  watt,  this  efficient  little  set  should 
appeal.  The  set  is  a  20  watt  trans- 
mitter using  4-5  watt  tubes.  By  means 
of  a  double  throw,  double  pole  switch, 
the  set  may  be  used  for  either  phone  or 
continuous  wave  telegraphy.  The  cir- 
cuit is  the  well-known  three  coil  Meissner. 

Power  Supply.  Telephony  has  today 
reached  such  a  state  of  development 
that  not  only  must  the  voice  be  carried 
in  an  intelligent  manner,  but  it  must 
be  a  true  reproduction  of  the  original, 
free  from  distortion  and  unaccompanied 
by  stray  noises  and  hums.  The  "pure 
wave"  is  also  an  important  factor  in 
telegraphy  efficiency  and  the  reduction 
of  interference.  The  nearest  practical 
approach  to  this  "pure  wave"  is  the 
current  delivered  by  a  property  designed 
motor  generator  set.  From  the  view- 
point of  good  telephony,  efficiency, 
flexibility  and  convenience,  an  "Esco" 
Item  No.  33  has  been  chosen  as  the 
source  of  power  supply.  This  type  is  a 
four  bearing  two  unit  set.  The  gen- 
erator is  of  the  double  commutator 
type,  supplying  100  watts  at  10  volts 
for  the  filaments  and  200  watts  at  500 
volts  for  the  plates.  Regulation  of  the 
output  power  is  obtained  by  means  of 
a  rheostat  in  the  field  of  the  generator. 

Filter.  The  filter  is  the  conventional 
three  section  "pi"  type.  The  induc- 
tances should  all  be  equal  and  from  10 
to  30  henries  each.  The  condensers 
should  be  from  2  to  4  henries  each.  The 
rules  for  combining  filter  sections  should 
be  strictly  adhered  to;  i.  e.,  Ci  equals 
C4,  and  C-2  equals  C3,  and  under  all 
conditions  Ci  equals  one  half  C2.  Were 
it  not  for  the  use  of  telephone,  the 
modulation  choke  could  be  omitted. 
The  omission  of  this  choke  would  permit 
the  large  condensers  of  the  fsJter  system 
to  by-pass  the  modulating  frequencies 
and  all  attempt  at  telephony  would 
result  in  an  unintelligible  gurgle.  A 
five  to  ten  henry  choke  will  be  sufficient. 
Due  to  the  by-pass  effect  of  the  larger 


condenser  for  audio  frequency,  the  radio 
frequency  by-pass  condenser  C6  should 
not  be  larger  than  .01  mfd. 

Meters.  Upon  the  intelligent  use  of 
the  meters  depends  the  efficiency  of  the 
set.  A  properly  operated  set  will  work 
rings  around  an  improperly  operated 
set  of  much  larger  power.  The  plate 
milliammeter  should  be  of  0-300  milli- 
ampere  capacity.  The  filament  volt- 
meter from  0-12  volts.  The  antenna 
ammeter  should  be  of  the  thermocouple 
type  from  0-3  amperes.  The  above 
meters  are  essential  to  the  practical 
operation  of  the  set.  Two  additional 
meters  will  be  of  great  help.  A  plate 
voltmeter  of  from  0-600  volts  and  an 
additional  thermocouple  meter  to  put 
in  the  antenna  circuit.  With  an  ammeter 
in  the  antenna  lead  and  one  in  the 
counterpoise  lead,  it  will  be  impossible 
to  obtain  a  balanced  condition  with  a 
resulting    greater    efficiency. 

General.  The  three  coils  may  be 
of  either  the  helix  or  pan-cake  type. 
The  hinged  pan-cake  type  is  to  be  pre- 
ferred, as  the  coupling  may  be  easily 
varied  and  part  turn  taps  are  more 
easily  effected.  The  aerial  and  counter- 
poise condensers  should  be  of  the  trans- 
mitting type,  capable  of  withstanding 
radio  frequency  of  high  voltage.  The 
use  of  two  is  not  essential  if  a  balanced 
condition  is  not  sought.  The  usual 
condensers  across  the  grid  and  plate 
coils  have  been  omitted.  While  they  are 
a  slight  aid  in  tuning,  they  constitute 
a  constant  loss  and  often  cause  the 
radiation  of  other  waves  than  the  funda- 
mental. Keying  is  accomplished  by 
means  of  a  relay  which  may  easily  be 
made  from  a  telegraph  sounder.  As 
this  relay  is  in  the  grid  circuit,  it  should 
be  mounted  as  near  the  tubes  as  possible, 
and  be  connected  with  short  leads. 
Both  the  relay  and  the  current  through 
the  modulating  transformer  are  con- 
trolled from  jacks  on  the  panel.  A 
small  knife  switch  should  be  used  to 
shunt  the  relay  when  telephony  is  being 
used.  A  4-8  volt  battery  should  be  used 
for  modulation  and  may  also  be  used  to 
operate  the  relay. 


RADIO  AGE /or  May,  1925 


The  Magazine  of  the  Hour 


59 


International  Radio  Problems 
Come  to  Fore 

WASHINGTON,  D.  C— With  the 
passage  of  the  bill  carrying  the 
State  Department's  budget  of  $.75,000, 
plans  for  the  International  Radio  Con- 
ference to  be  held  here  in  September 
are  being  formulated.  The  actual  agenda 
depends  somewhat  upon  what  action 
the  world  telegraph  conference  at  Paris 
takes  this  Summer.  The  United  States 
will  not  be  officially  represented  as  it 
is  not  a  party  to  the  conventions.  A 
careful  study  of  the  action  taken  there, 
especially  with  reference  to  the  attitude 
of  the  World  Powers,  will  be  made  by 
American  Governmental  officials  and 
radio  experts,  in  order  that  the  general 
trend  of  opinion  on  electrical  communica- 
tions may  be  followed. 

It  may  be  found  more  practical  to 
eliminate  discussion  on  strictly  technical 
matters,  such  as  specific  wave  channels, 
power  limitation  and  such  matters,  as 
they  might  tie  up  development  in  a 
mass  of  technicalities,  which  could  not 
be  changed  for  three  or  four  years. 

The  essentials  of  world-wide  radio 
communication  will  be  covered  in  the 
Paris  Conference,  since  they  are  in- 
corporated under  the  clause  of  the  old 
telegraph  convention  of  1908,  covering 
ship-to-shore  radio  communication.  It 
is  believed  that  the  Paris  conference  will 
extend  these  regulations  to  cover  trans- 
oceanic radio  services.  If  this  is  the 
case,  radio  service  in  general,  licenses, 
classification  of  messages,  accounts  and 
rates  may  •  be  outlined  at  Paris  prior 
to  the  American   conference. 

It  is  quite  probable  that  a  broader 
conception  may  be  placed  upon  the  old 
plan  for  allocating  high-power  com- 
mercial stations  throughout  the  world. 
Advanced  thinkers  on  this  subject  believe 
that  the  location  of  commercial  stations 
within  the  boundaries  of  a  country  is 
a  matter  for  the  particular  country  to 
determine.  The  international  allocation 
of  signals,  such  as  distress  and  general 
calls,  as  well  as  the  assignment  of  high- 
powered  station  call  letters,  will  be  dis- 
cussed, although  it  is  believed  that  this 
matter  will  continue  to  be  handled  by 
the  central  bureau  at  Berne.  Inter- 
national broadcasting  by  amateurs  may 
be  considered,  as  recently  the  amateur 
has  come  into  world  prominence,  and 
his  call  letters,  although  national,  have 
no  definite  significance  in  another  foreign 
country,    and    may    be    duplicated. 

As  most  of  the  countries  of  the  world 
are  parties  to  either  the  telegraph  or 
the  radio  conventions,  it  is  likely  that 
more  than  fifty  separate  governments 
will  send  delegates  to  the  United  States 
this  fall  to  participate  in  the  delibera- 
tions on  radio  regulations. 

The    1920    Conference 

In  October,  1920,  about  a  year  before 
America  in  general  became  vitally  in- 
terested in  radio,  a  preliminary  radio 
conference  was  held  in  Washington, 
where  representatives  of  Great  Britain, 
France,  Japan  and  Italy  met  to  draw 
up  an  outline  program  for  future  dis- 
cussion. Most  of  the  visiting  delegation 
were    headed     by    the     respective     am- 


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«T  didn't  think  that  tubes 
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You,  too,  will  be  pleasantly 
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60 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


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bassadors  and  ministers,  and  the  United 
States  was  represented  by  Under  Secre- 
tary of  State  Davis,  Postmaster  General 
Burleson,  Admiral  Benson  of  the  Shipping 
Board    and    Walter    Rogers. 

The  conferees  laid  down  proposals 
under  the  following  subdivisions:  The 
radio  protocol  of  the  Peace  Conference; 
a  universal  communication  union,  com- 
posed of  telegraph  and  a  radio  sections; 
International  telegraph,  radio  and  cable 
laws;  and  improvements  in  the  com- 
munication facilities  between  the  five 
great    Powers. 

The  British  submitted  a  plan  for  the 
amalgamation  of  all  electrical  com- 
munication rules  and  regulations  to  be 
submitted  to  a  world's  congress  on  com- 
munications, which,  however,  never  ma- 
terialized. 

The  old  international  code  system,  a 
method  of  communicating  between  sta- 
tions or  ships  of  different  nations,  was 
pronounced  out  of  date  and  not  adapted 
for  radio.  Provision  for  transmitting 
messages  intelligible  to  all  operators, 
regardless  of  the  language  they  spoke, 
was  planned  for  use  in  sea  and  aerial 
navigation;  covering  damages,  sickness, 
stores,  fuel,  meteorology,  ship  and  air- 
craft  business,   and   other   special  needs. 

Although  the  State  Department  has 
made  no  official  move  toward  calling  the 
nations  of  the  world  to  this  conference, 
it  is  understood  that  formal  invitations 
will  soon  be  sent  out,  and  the  working 
up  of  a  program  begun. 


"What  is  Radio?" 

"Wish  I  knew  something  about  radio — 
not  the  technical  part,  you  know,  just 
enough  to  understand  what  it's  all  about." 

Yes,  and  the  people  you  hear  say  this 
are  only  a  small  part  of  the  thousands 
who  think  it. 

Lack  of  knowledge  and  consequent 
diffidence  or  uncertainty  are  the  greatest 
handicaps  of  the  radio  industry  today. 
Untold  thousands  of  people  are  not  buy- 
ing radio  sets  simply  because  they  are 
afraid.     They  don't  know. 

It  is  to  meet  this  need  that  the  makers 
of  the  Somerset  radio  receivers  have  pub- 
lished a  unique  booklet  for  beginners — 
the  Somerset  Radio  Primer,  "a  little 
book  for  the  man  who  knows  nothing 
about  radio,"  telling  him  what  radio  is, 
and  how  to  choose  a  radio  receiver. 

It  is  written  for  people  who  are  not 
familiar  with  electrical  or  mechanical 
terms  and  principles  but  who  would  like 
to  know  the  general  idea  for  radio  recep- 
tion. 

Leaving  out  the  technicalities  and  re- 
finements, it  tells  the  story  briefly,  clearly 
and  interestingly.  Difficult  points  are 
explained  by  analogy  with  familiar  ob- 
jects. 

For  example,  the  action  of  a  rheostat 
is  compared  with  that  of  an  ordinary 
faucet  in  its  control  of  the  following 
stream  of  water. 

There  are  many  illustrations  showing 
the  principal  parts  of  radioreceiving  out- 
fits, with  a  brief  description  of  each  part. 

The  Somerset  Radio  Primer  has 
caused  enthusiastic  approval  wherever 
shown.  The  Primer  is  intended  for  dis- 
tribution by  Somerset  dealers  and  is 
furnished  with  the  dealer's  name  im- 
printed on  the  cover.  Sample  copies  may 
be  had  by  writing  direct  to  the  makers  of 
Somerset  receivers,  the  National  Air- 
phone  Corporation,  22  Hudson  St., 
New  York. 
#     Tested  and  Approved  by  RADIO  AGE     * 


Europeans  Seek  Protection 
for  Radio  News 

RECOGNIZING  radio  as  a  modern 
means  of  transmitting  news,  the 
members  of  about  twenty-five  press 
associations  in  Europe  have  taken  steps 
to  protect  their  property  when  it  is  en 
route  through  the  air.  Resolutions 
signed  by  such  well-known  news  agencies 
as  Havas  of  France,  Continental  of 
Germany,  Fabra  of  Spain,  Reuters  of 
Great  Britain,  Stefani  of  Italy  and 
Rosta  of  Russia  have  been  filed  with 
the  International  Telegraphic  Union 
at  Berne.  Other  suggestions  will  be 
submitted  to  the  International  Conven- 
tion for  the  Protection  of  Industrial 
Property,  which  meets  at  the  Hague  in 
October. 

What  amounts  to  radio  censorship  is 
suggested,  broadcast  transmission  would 
be  controlled,  receiving  sets  limited  and 
many  phases  of  radio  operation  definitely 
regulated,  if  the  plan  is  carried  out 
internationally. 

Essentially,  the  foreign  press  associa- 
tions insist  on  ethereal  property  rights, 
patent  protection,  and  punishment  when 
their  copy  is  picked  up  and  used  with- 
out permission.  They  recommend  that 
a  technical  means  which  will  prevent  the 
reception  and  use  by  unauthorized 
persons  of  press  matter  transmitted  by 
radio,  be  developed.  Simple  methods 
of  ciphering  and  deciphering,  insuring 
rapidity  of  handling,  have  been  devised, 
and  partially  secret  radio  apparatus 
has  been  perfected  but  not  adopted 
generally.  In  Europe  the  governments 
control  and  operate  radio  as  they  do 
practically  all  communication  systems; 
therefore,  it  might  be  a  practical  possi- 
bility. But  in  the  United  States,  where 
private  companies  handle  communica- 
tions, great  difficulties  would  be  en- 
countered in  this  connection. 

It  was  also  recommended  that  national 
governments  agree  not  to  authorize  the 
establishment  or  maintenance  of  any 
private  radio  receiving  stations  until 
the  authorities  have  taken  all  precautions 
to  strictly  limit  the  capacity  of  the  re- 
ceiving set.  That  is,  receivers  would 
be  constructed  or  set  so  as  to  pick  up 
only  matter  broadcast  on  certain  wave 
bands  and  not  on  those  channels  carry- 
ing news.  This  sealing  of  sets  has  been 
attempted  in  some  countries  unsuccess- 
fully, and  certainly  would  be  a  tre- 
mendous undertaking  in  the  United 
States  with  several  million  unlicensed 
receiving  sets  to  locate  and  adjust,  even 
if  it  became  a  law. 

Strong  Ban  Asked 

Positive  legislation  against  violation 
of  secrecy  and  illicit  use  of  press  matter 
is  urged.  As  penalties  for  the  use  of 
unauthorized  radio  news,  these  organ- 
izations desire  imprisonment,  confisca- 
tion and  damages,  as  well  as  forfeiture 
of  licenses,  if  illicit  use  is  proven. 

Reduced  telegraph  rates  for  press 
matter  are  asked,  and  assurance  that 
delayed  messages  will  go  forward  at 
press  rates,  despite  the  lapse  of  time 
fixed  for  press  rates  to  apply. 

Further,  the  signatories  ask  that  if 
broadcast  concessions  are  made,  the  con- 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


61 


cessionaires  be  required  not  to  send  out 
political,   commercial,   financial  or  other 
news    except    that    which    is    submitted 
and   filed   by   recognized   news   agencies. 
This  is  a  curious  reversal  of  the  situation 
in   the   United   States,    where   the   Asso- 
ciated   Press   has   refused    to    permit    its 
news  items  to  be  broadcast.     The  prop- 
erty value  of  press  news  has  never  been 
established  internationally,  it  is  pointed 
out,  except  that  in   some  instances  pro- 
tection    after     publication     is     afforded, 
which  would  not  benefit  the  news  collect- 
ing and  distributing  agencies.     In  other 
countries,     cnly     what     are     considered 
literary   works   are   protected   by   law. 

The  members  of  the  foreign  press 
associations  claim  that  radio  broad- 
casting is  a  menace  to  them  as  well  as 
to  the  public,  on  account  of  "the  ease 
thereby  given  to  the  spread  of  uncon- 
trolled  news." 

How  these  suggestions  will  affect  the 
news  associations  and  the  private  com- 
munication companies  in  this  country, 
as  well  as  the  broadcasters  and  listeners, 
is  unknown,  but  as  American  repre- 
sentatives will  be  present  at  the  con- 
ferences, it  is  assumed  that  all  interests 
will  be  protected  in  the  event  inter- 
national   agreements   are   drawn    up. 


Market  for  Tapped  "B"   Batteries 
Falling  Off 

The  waning  popularity  of  the  "soft" 
tube  has  greatly  reduced  the  demand  for 
tapped  "B"  batteries,  according  to  manu- 
facturers of  dry  cells  for  plate  current 
supply. 

Until  the  development  of  satisfactory 
methods  of  radio  frequency  amplifica- 
tion, sensitiveness  in  the  detector  was  a 
highly  important  requirement  for  long 
distance  reception.  The  great  disad- 
vantage of  the  "soft"  tube  is  the  precise 
adjustment  of  plate  and  filament  voltage 
which  is  required  to  operate  it  at  the  most 
sensitive  point.  Very  few  users  of  "soft" 
tubes,  on  account  of  this  difficulty,  ever 
secure  the  added  sensitiveness  which  it 
gives  only  under  the  most  favorable 
circumstances. 

The  adjustment  problem  is  further 
complicated  by  the  fact  that' the  most 
sensitive  combination  of  plate  and  fila- 
ment voltage,  once  found,  does  not  re- 
main fixed.  Sometimes  a  new  adjust- 
ment in  order  to  "hold"  a  distant  station 
is  required  in  the  midst  of  a  program. 

The  more  modern  types  of  high  vacuum 
tubes,  utilizing  but  a  fourth  of  the  fila- 
ment current  required  by  "soft"  tubes, 
give  as  good  results  as  those  obtained  with 
the  "soft"  detector  tube,  for  sets  using 
radio  frequency  amplification. 

Dealers  selling  tubes  perform  a  service 
to  their  customers  if  they  make  sure  that 
the  type  passed  over  the  counter  is  best 
.adapted  to  the  use  for  which  it  is 
intended.  In  any  receiver  employing 
radio  frequency  amplification,  the  saving 
in  filament  current  and  the  availability 
of  more  compact  and  more  economical 
"B"  batteries,  make  it  advisable  to 
recommend  high  vacuum  tubes  instead 
of  the  obsolescent  "soft"  detector  tube. 


IS  IT  JAZZ? 

It  is!  Anything  you  hear  on  RADIO 
AGE'S  Congress  Carnival  from  KYW, 
Chicago  on  Saturday,  May  2,  from 
11:30  p.  m.  to  1  a.  m.,  is  going  to  be  jazz 
and  then  some.     Tune  in  for  a  good  time! 


&i 


K^liahitity 


'TPHAT  trait  of  thoroughness  which   merits   confidence   is   always 

met  with  high  regard.     For  there  is  deep  satisfaction  in  knowing 

that  the  task  in  hand  is  being  done  as  well  as  it  is  possible  to  do  it. 

This  appreciation  for  reliability  has  established  the  leadership 
enjoyed  by  Jefferson  Transformers.  Sheer  quality  and  perfor- 
mance have  won  the  favor  of  unbiased  radio  authorities  the  world 
over. 

Full,  rounded  amplification  over  the  entire  musical  range — a 
constant  delight  to  radio  listeners.  Such  splendid  performance  is 
the  result  of  20  years'  specialization  in  the  manufacture  of  trans- 
formers. Replace  the  transformers  now  in  your  set  with  genuine 
Jeffersons  and  see  how  your  set  will  improve. 

Jefferson  Electric  Mfg.  Co. 


507  South  Green  St. 


CHICAGO 


Radio  Transformers 

Bell  Ringing  Transformers 

Sign  Lighting  Trans- 


Manufacturers  of: 

Jump  Spark — Make  and 

Break     Coils 
Auto  Transformers 
Testing  Instruments 
Toy  Transformers 


trnace  and    Oil    Bu 
Transformers 
.il   Burner  Igni! 


nd    Low    Vol- 


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P05T  PAID 


All  the  720  Broadcasting 
Stations  of  North  Am 
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The  Radex  Press 


Have  you  BOUGHT 
YOUR  ANNUAL? 

Tested  and  Approved  by  RADIO  AGE     # 


We    Equip  You 

To  be  a  Federal  Radio  Dealer  and  guarantee  your 
success  under  the  "Gould  Plan"  which  allows  you  to 
I  return  merchandise  which  you  are  unable  to  sell. 
"We  sell  wholesale  to  dealers  only.  Write  for  our 
price  list  and  FREE  Instructions  "HOW  TO  SELL 
RADIO." 

FEDERAL  RADIO  CO. 

i  115  East  13th  St.,  Kansas  City,  Mo. 


62 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


FIT  FOR  A  KING 

Britain's  greatest  engineers  in  designing 
receiving  equipment  for  his  Majesty 
KING  GEORGE  V.  chose  Resistance 
Coupled  Amplification.  None  other 
would  do. 

THE  DAVEN  RESISTANCE 
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finesse  in  quality  amplification  desired 
for  the  Chambers  of  Buckingham  Palace. 
With  Resistance  Coupling  the  most  deli- 
cate shadings  in  musical  compositions, 
either  with  instruments  or  the  voice,  are 
reproduced  with  a  faithfulness  not 
obtainable  with  any  other  method  of 
audio  amplification. 

Your  Dealer  will  be  glad  to  show  you  the 
Super  Amplifier  which  can  be  attached 
to  your  favorite  tuner  in  but  a  few 
moments.  It  costs  less  to  install  than 
other  methods  of  amplification  and  adds 
greatly  to  the  life  of  your  "B"  Batteries. 
DAVEN  RESISTANCE  COUPLED 
KITS  are  put  up  in  three  and  four  stages 
and  are  for  those  who  would  rather 
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Obtain  from  your  Dealer  the  RESISTOR 
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DAVEN  RADIO  CORPORATION 

"Resistor  Specialists" 

NEWARK,  NEW  JERSEY 


T"PV  readers  wish  to  show  their 
["*  approval  of  RADIO  AGE'S 
stand  against  the  Radio 
Corporation  of  America,  they  can 
do  it  in  the  most  practical  way  by 
sending  in  $2.50  for  a  year's  sub- 
scription or  if  they  are  already  sub- 
scribers, urge  a  friend  to  subscribe. 
We  believe  the  fans  are  with  us. 
Address  RADIO  AGE,  Inc.,  500  N. 
Dearborn  St.,  Chicago,  111. 


THE    RADIO    AGE 
BUYERS'    SERVICE 

What  do  you  want  to  purchase  in  the  radio  line?  Let  the  staff  of  RADIO  AGE  save  you 
time  and  money  by  sending  in  the  coupon  below.  Enter  the  number  of  the  article  you 
would  like  to  know  more  about  in  the  spaces  provided  in  the  coupon. 


1  "A"  Batteries 

2  Aerial  protectors 

3  Aerial  insulators 

4  Aerials 

5  Aerials,  loop 

6  AmpH6ers 

7  Amplifying  units 

8  Ammeters 

9  "B"  batteries 

10  Batteries   (state  voltage) 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery   substitutes 

17  Bezels 

18  Binding  posts 

19  Binding  posts,  insulated 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatatone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 
3i   Cat  whiskers 

32  Code  practisers 

33  Coils 

34  Coils,  choke 

35  Coils,  coupling 

36  Coils,  niter 

37  Coils,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance 

40  Coils,  Reinartz 

41  Coils,  stabilizer 

42  Coils,  tuning 

43  Condenser  parts 


,  coupling 
,  filter 
sers,  fixed  (paper, 


lin 

46  Co 

47  Co 

48  Co 

49  Co 
grid,  or  phi 

50  Condensers,  variable  gr 

51  Condensers,  variable  m 

52  Condensers,  vernier 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  sets 

57  Couplers,  loose 

58  Couplers,  molded 

59  Couplers,  vario 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 

71  Dial,  adjusters 

72  Dials,  composition 

73  Dials,  hard  rubber 

74  Dials,  rheostat 

75  Dials,  metal 

76  Dials,  vernier 

77  Dials  with  knobs 

78  Dies 

79  Drills,  electric 

80  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

83  Enamels,  battery 

84  Enamels,  metal 

85  End  stops 

86  Eyelets 

87  Experimental  work 

88  Fibre  sheet,  vulcanized 

89  Filter  reactors 

90  Fixtures 

91  Fuse  cut  outs 

92  Fuses,  tube 

93  GeneratorB.high  freque 

94  Grid  choppers,  rotary 


s,  metal 


cators. 

polarity 

ictances.  C.  W. 

Ution 

molded 

lotion 

material 

lators. 

lators. 

compoait 

lators. 

fibre 

lators, 

high  volt! 

cloth 

glass 

la  tor., 

hard  rub 

la  tor., 

porcelain 

,  testin 


95  Grid  leak  holder, 

96  Grid,  transmitting  leak, 

97  Grid  leak.,  tube 

98  Grid  leak,,  variable 

99  Grinder,,  electric 

100  Ground  clamp, 

101  Ground  rod, 

102  Handle,,  switch 

103  Head  bands 

104  Head  phone, 

105  Head  sets 

106  Honeycomb  coil  adapter! 

107  Hook  ups 

108  Horns,  composition 

109  Horns,  fibre 

110  Hon 

111  Hon 

112  Hon 

113  Hyd 

114  Indi 

115  Indi 

116  Insu 

117  Insu 

118  Insu 

119  Insu 

120  Insu 

121  Insu 

122  Insu 

123  Insu 

124  Insu 

125  Insu 

126  Iron 

127  Jacks 

128  Filament  cor 

129  Jars,  battery 

130  Keys,  transir 

131  Knobs 

132  Knock-down 

133  Laboi 

134  Lever,  switch 

135  Lightning  arreste 

136  Loo.ecouplers 

137  Loud  speakers 

138  Loud  speaker  unil 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instrui 

142  Megohmeters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeters 

148  Minerals 

149  Molded  in 

150  Molybden 

151  Mounting 

152  Mounting 
leak 

153  Mounting 

154  Mounting 

155  Mounting 
coil 

156  Mountings,      inductance 
switch 

157  Name  plates 

158  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeters 

161  Oscillators 

162  Panel  cutting  and  drillii 

163  Panels,     drilled     and     u 
drilled 

164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  soldering 

168  Patent  attorneys 

169  Phone  connectors,  mult 
pie 

170  Phonograph  adapters 

171  Plates,  condenser 

172  Plugs,  coil 

173  Plugs,  telephone 

174  Pointers,  dial  and  knob 

175  Poles,  aerial 

176  Potentiometers 

177  Punching  machines 

178  Reinartz  set  parts 

179  Regenerative  set  parts 

180  Receiver  caps 

181  Rectifiers,  battery 

182  Resistance  leaks 

183  Resistance  units 

184  Rheostat  bases 

185  Rheostat  strips 


ulatio 


grid  leak 
honeycon 


186  Rheostats,  automatic 

187  Rheostats,  battery 

188  Rheostats,  dial 

189  Rheostats,  filament 

190  Rheostats,     potentiomete 

191  Rheostats,  power 

192  Rheostats,  vernier 

193  Rods,  ground 

194  Rotors 

195  Scrapers,  wire 

196  Screwdrivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving— cabinet 

200  Sets,  receiving — crystal 

201  Sets,     receivin 
down 


202  Sets, 
dyne 

203  Sets,  I 

204  Sets, 


knock- 
Neutro- 


ig — portable 
ng — radio  fre- 


-regenera- 


207  Sets,    receiving — Reinartz 

208  Sets,  receiving — sectional 

209  Sets,  receiving — shortwave 

210  Sets,    receiving — super-re- 

211  Sets,  transmitting 

212  Slate 

213  Shellac 

214  Sliders 

215  Socket  adapters 

216  Sockets. 

217  Solder 

218  Soldering  irons,  electric 

219  Soldering  paste 

220  Solder  flux 

221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 

226  Stampings 

227  Stators 

228  Stop  points 

229  Switch  arms 

230  Switch  levers 

231  Switch  point, 

232  Switch  stops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switches,  ground 

237  Switches,  inductance 

238  Switches,  panel 

239  Switches,  single  and  dou- 
ble throw 

240  Tone  wheels 

241  Towers,  aerial 

242  Transformers, 


(ra- 
ters, filament 
lers,  modulation 
lera,  power 
lers,  push-pull 
lers,      radio     fre- 

lers,  variable 


—three  ele- 


243  Transforr 

244  Transforr 

245  Transforr 

246  Transforr 

247  Transforr 
quency 

248  Transforr 

249  Transmit 

250  Tubes,  va 

251  Tubes,    vi 

252  Tubes,  va 


253  Tuners 

254  Variocouplers,  hard  rubber 

255  Variocouplers.  molded 

256  Variocouplers.  wooden 

257  Variometers,  hard  rubber 

258  Variometers,  molded 

259  Variometers,  wooden 

260  Varnish,  insulating 

261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 

265  Wire,  aerial 

266  Wire.jbraided  and  stranded 

267  Wire,  copper 

268  Wire,  insulated 

269  Wire,  Litz 

270  Wire,  magnet 

271  Wire,  platinum 

272  Wire,  tungsten 


RADIO  AGE  BUYERS'  SERVICE,  500  N.  Dearborn  St.,  Chicago,  III. 

Please  see  that  I  am  supplied  with  buying  specifications  and  prices  on  the  articles  numbered  herewith: 


■T 


I       I 


1      1       1 


I       I       I       I 


lama —  Q  Dealer  __■   Jobber 

Firm      [If  identified  with  Radio  industry] 

My    Occupation   _ ... 

My    Name    _ 

Address    _ 


_    Mfgrs/  Rep.  □    Manufacturer 


City 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


63 


KYW  Heard  Regularly  in 
Samoa 

SOUTH  Sea  nights, —  a  lanquid  tropical 
moon, — the  cool  of  the  seaward 
veranda  and  the  ever-present  shimmer- 
ing glass  on  the  table,  with  its  attendant 
tinkle,  have  always  been  regarded  as  the 
white  man's  paradise,  especially  for  those 
rovers  who  dot  the  spacious  Pacific  and 
who  prefer  to  think  of  the  United  States 
as  a  haven  7,000  miles  or  so  away. 

But  radio,  with  its  magic  wand,  has 
annihilated  distance  and  although  the 
nights,  the  moon"  and  the  refreshments 
are  still  part  and  parcel  of  the  colonials' 
lives,  yet  a  new  attraction  has  been 
added. 

All  of  which  should  serve  as  a  prelude 
to  the  letter  of  ecstasy  received  from 
A.  F.  Dunwoodie,  of  Apia,  Samoa,  a 
mere  seven  or  eight  thousand  miles  from 
Chicago,  in  which  it  is  stated  that  the 
programs  broadcast  by  KYW  from  the 
Balloon  Room  of  the  Congress  Hotel, 
where  Coon  and  Sanders  play, — which 
music  and  fun  goes  under  the  name  of 
the  "Insomnia  Club,"  is  heard  nearly 
every  night  out  in  Apia,  Samoa. 

This  is  not  the  first  time  that  KYW  has 
been  heard  in  Samoa,  for  last  year  Mr. 
Dunwoodie  also  wrote  the  station  regard- 
ing his  reception  of  its  programs.  But 
the  thing  which  appeals  to  Mr.  Dun- 
woodie is  the  fact  the  Insomnia  Club 
feature  broadcast  by  KYW  from  the 
Congress  Hotel  every  morning  from  1 
a.  m.  to  2  a.  m.  and  on  Sunday  morning 
from  1  a.  m.  to  3  a.  m.,  reaches  Samoa 
about  seven  o'clock  in  the  evening  and 
serves  as  an  excellent  aperitif  for  the 
evening  meal  of  many  a  radio  enthusiast. 
Between  Chicago  and  Samoa,  the  latter 
being  in  the  one  hundred  and  eightieth 
parallel,  there  is  approximately  six  hours 
difference  in  time,  making  it  possible  for 
Mr.  Dunwoodie  to  sit  down  to  his  supper 
table  in  Samoa  and  hear  radio  jazz  music 
broadcast  by  KYW  from  the  Balloon 
Room  where  the  original  Nighthawks, 
Coon  and  Sanders,  play  at  a  time  that 
is  fairly  close  to  the  breakfast  hour  of 
the  residents  of  the  Middle  West  of  the 
United   States. 

Apparently  there  is  little  interference 
developing  in  the  South  Seas,  although 
thousands  of  ships  on  the  Pacific  are 
transmitting  on  600  meters  and  KYWs 
wavelength  is  535.4  meters,  for  Mr. 
Dunwoodie  does  not  report  any  trouble 
in  picking  up  KYWs  carrier  wave  and 
holding  it  until  he  has  extracted  all  the 
pleasure  and  fun  from  its  Insomnia  Club. 


Banks  Kennedy  Now  a  Radio  Age 
Star 

Banks  Kennedy,  who  has  amused 
countless  thousands  through  his  radio 
antics  from  KYW  and  WEBH,  Chicago, 
has  been  "signed  up"  permanently  as  a 
RADIO  AGE  performer  from  those  and 
other  broadcasting  stations.  Kennedy 
first  started  to  twinkle  when  he  intro- 
duced his  famous  "If  I  can  Arrange  It" 
song,  and  he  has  been  at  it  ever  since. 
He  may  be  heard  from  WEBH  Tuesdays 
and  Thursdays  after  lip.  m.,  and  at 
KYW  the  first  Saturday  in  every  month 
beginning  at  1 1 :30  p.  m..  on  the  Congress 
Hotel  Jazz  Carnival. 


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RADIO  AGE/of  MAY  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


Westinghouse  Electric  &  Mfg.  Co East  Pittsburgh  309 

Radio  Electric  Co Devils  Lake,  N.  D.  231 

Westinghouse  Electric  &   Mfg.   Co Cleveland,   Ohio  270 

Southern  Electrical  Co San  Diego,   Calif.  244 


Newho 


Hotel Salt    Lake    City,    Utah     250 


Savoy  Theatre San  Diego,  Calif.  280 

Frank    E.    Siefert Bakersfield,    Calif.  240 

Rhodes   Department   Store Seattle,    Wash.  270 

Electric  Supply  Co Wenatchee.  Wash.  360 

McArthur   Bros.   Mercantile   Co Phoeniz,   Arix.  360 

State  College  of  Washington Pullman,  Wash.  348 

Western    Radio   Corporation .Denver,    Colo.  278 

University  of  Colorado Boulder,  Colo.  360 

University  of   Idaho Moscow,   Ida.  230 


High  School. 


Idaho     271 


The  Radio  Den  (W.  B.  Ashford) .Santa  Ana,  Calif. 

F.  A.  Buttrey  &  Co Havre,  Mont. 

W.  K.  Azbill San   Diego,  Calif. 

Horn  &  Wihon's  "Rndioland" .' .  .  San  Luis  Obispo,  Calif. 

First   Presbyterian   Church Tacoma,   Wash. 

Kimball-Upson     Co Sacramento.      Calif. 

Leese  Bros Everett,  Wash. 

The     Cathedral Laramie,    Wyo. 

Nielson  Radio  Supply  Co Phoenix,  Ani. 

The  First  Congregational  Church Helena,   Mont. 

Frank  A.  Moore Walla  Walla,  Wash. 

Leslie  E.  Rice Los  Angeles,  Cal. 

Ralph  W.  Flygare Ogden,  Utah 

Omaha  Central  High  School Omaha,  Nebr. 

St.    Michaels    Cathedral ' Boise,    Idaho 

University  of  Arizona Tuscon,  Ariz, 

Oregon  Agricultural    College Corvallis,    Oreg. 

Magnolia  Petroleum  Co Beaumont,  Tex. 

First    Baptist   Church Shreveport.    La. 

South    Dakota   State   College Brookings,    S.    Dak. 

Harry    O.    Iverson Minneapolis,     Minn. 

Meier  &  Frank  Co Portland.  Oreg. 

Augsbury    Seminary Minneapolis.    Minn. 

Winner   Radio   Corp Denver,    Colo. 

J.  L.  Scroggin Oak,  Nebr. 

Auto  Electric  Service  Co FortDodge,  Iowa 


280 
360 
278 
218 
250 
283 
224 
283 
238 
248 
256 
236 
360 
258 
252 
368 
254 
315 
360 
360 
231 
248 
261 
254 
268 
231 


Bunker  Hill  &  Sullivan  Mining  and  Concentrating  Co Kellogg,  Idaho  233 

First    Baptist    Church Moberly,    Mo.  266 

Nevada  State  Journal  (Jim  Kirk) Sparks,  Nev.  226 

Graceland    College Lamoni,    Iowa  280 

Pincus   &    Murphy    Music    House Alexandria.    La.  275 

Heidbreder  Radio  Supply  Co Utica,  Neb.  224 

Louisiana    State    University Baton    Rouge.    La.  254 

Chickasha  Radio  &  Electric  Co Chickasha.  Okla.  248 

Leland  Stanford  University Stanford  University.  Calif.  273 

Crary    Hardware    Co Boone.    Iowa  226 

First  Presbyterian  Church Orange.   Tex.  250 

Western  State  College  of  Colorado Gunnison,  Colo.  252 

Ambrose  A.  McCue Neah  Bay.  Wash.  261 

Fallon  &  Co Santa  Barbara,   Calif.  360 

Penn     College.. Oskaloosa.     Iowa  240 

Star  Electric  *  Radio  Co Seattle.  Wash.  283 

E.  C.   Anthony,   Inc Los   Angeles,   Calif.  468 

Benson  Polytechnic   Institute Portland.   Oreg.  248 

North    Central    High    School Spokane,   Wash.  252 

First  Methodist  Church Yakima,   Wash.  242 

Alaska  Electric  Light  &  Power  Co Juneau.  Alaska  226 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints   Independence,  Mo.  240 

Daily  Commonwealth  and  Oscar  A.  Huelsman Fond  du  Lac.  Wis.  273 

Marshall    Electrical    Co Marshalltown,    Iowa  248 

National  Radio  Manufacturing  Co Oklahoma  City.  Okla.  252 

Liberty  Theat-c  (E.  E.  Marsh) Astoria.  Oreg.  252 

Hardsacg    Manufacturing    Co Ottumwa.     Iowa  242 

University  of  North  Dakota Grand  Forks.  N.  Dak.  280 

Ashley  C.  Dixon  &  Son Stevensville.  Mont,    (near)  258 

Iowa  State  Teacher's  College Cedar  Falls,  Iowa  280 

Tunwall   Radio   Co ■• Fort   Dodge,   Iowa  246 

Texas  National  Guard.  One  hundred  and  twelfth  Cavalry. Fort  Worth.  Texas  254 

Colorado  State  Teachers  College  Greeley.  Colo.  273 

Brinkley-Jones     Hospital    Association Milford.     Kans.  286 

Conway  Radio  Laboratories  (Ben  H.  Woodruff) Conway,  Ark.  250 

The  University  of  Kansas Lawrence.  Kans.  275 

F.  F.    Gray Butte,    Mont.  283 

Westinghouse  Electric  &  Manufacturing  Co Hastings,  Nebr.  288 

Abner  R.  Willson Butte.  Mont.  283 

Signal  Electric  Manufacturing  Co Menominee.  Mich.  248 

Paul    E.    Greenlaw Franklinton.    La.  234 

National    Educational    Service Denver.    Colo.  268 

Everett  M.   Foster Cedar   Rapids.    la.  256 

University    of    New    Mexico Albuquerque,    New    Mexico  254 

Rio  Grande   Radio  Supply   House San   Benito,   Texas.  236 

Rev.  A.  T.  Frykman Rockford.   111.  229 

George  Rov  Clough Galveston.  Tex.  240 

Atlantic  Automobile   Co ■ Atlantic.   la.  273 

Christian   Churches Little    Rock,   Ark.  254 

University  of  Akransas Fayetteville.  Ark.  299 

Morningside  College ■  .Sioux  City,  Iowa  261 

Dr.    George    W.    Young Minneapolis.    Minn.  231 

M.  G.  Sateren Houghton.  Mich.  266 

Carleton  College Northfield    Minn.  336 

Henry  Field  Seed  Co Shenandoah,  Iowa  266 

Wooten's  Radio  Shop Xloldwater,  Miss.  254 

Central  Mo.  Stare  Teachers  College Warrensburg    Mo.  234 

Radio  Broadcast  Ass'n Paso  Robles.  Calif.  240 

L  A    Drake  Battery  and  Radio  Supply  Shop Santa  Rosa,  Calif.  234 

Montana    Phonograph    Co -        Helena.    Mont.  261 

Royal     Radio     Company Burlingame,     Calif.  231 

Rhodes    Department    Store ig?»™e'     S8?.™'  X?2 

First    Christian    Church Whrttier,    Cahr 


Idaho  224 

MoberlyHigh  School  Ridio  Clut  Moberly.  Missouri  246 

Leslie    M.    Schafbush ■    Marengo,    Iowa  234 

Echophone  Radio  Shop -  ■  ■  I-onf  Beach.  Calif.  234 

Latter  Day  Saints  University Salt  Lake  City    Utah  261 

Rohrer  Elec.  Co ■  •  ■  .J^rrshfi.f"-  °">-  "0 

David  City  Ti-c  .1-  Electric  Co D™"»r;  Nebraska  226 

College  Hill  Radio  Club ■?  ichita    Kansas  231 

Hommel  Mfg.  Co •  •  •  •  ■  •  ■ ; ,?'C  ^"ItY      t  ?2a 

Board  of  Education.  Technical  High  School Omaha^Neb-aska  248 

224 
233 


l.llll'ii.      L  •   '  ""  ■'.■■■---■*-  -  ■  ,  , 

Beacon  Radio  Sen-ice I'-J??1"1' w    t 

Edwin    ,T.    Brown ..Seattle.    Wash 

Oarretson  end  Dennis •  ■  Jj<»  Ans£lf  •  \fr}l{      , 

Harold  Chas.  Mailander Salt  Lake  City.  Utah     242 

C.    C.    Baxter „  Dublin.    Texas     242 

The   New   Furniture   Co .  Greenvrl  e.   Texas 

Los  Angeles  Co.  Forestry  Dept -Los  Angeles,  Calif. 

Cape  &  Johnson Salt  Lake  City,  Utah 

Heintz  *  Kohlmoos.  Inc , San  Francisco.  Calif. 

St.  Johns  ME.  Church £arteiT"LC'  ¥t' 

First  Presbyterian  Cbnrch Pine  Bluff    Ark. 

Svmons  Investment  Co Spokane.  Wash. 

The     Principle ■■ £*■    -^>nfr    iT°' 

The  Searchlight  Publishing  Co Fort  Worth.  Tex 

Kidd    Brothers    Radio    Shop ..Taft,    Cabf.     258 

Southern  Calif.  Radio  Ass'n Los  Angeles.  Calif. 

Radio   Service    Co Burhngame.    Calif. 

Texas     Highway     Bulletin iAufm;     I61' 

Third    Baptist    Church .Portland.    Ore. 

G.   S.   Carson,   Jr Iowa    City,    la. 

Walter   LaFayette  Ellis Oklahoma   City,    Okla. 

Texas  National  Guard Denmson,  Texas 


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W.  Riker Holy  City,  Calif.  253 

C.  F.  Knierim North  Bend.  Wash.  248 

Alfred    M.    Hubbard Seattle,    Wash.  233 

.Belden,    Neh.  273 


State    Bank. 


Fan 

Taft    Radio    Co Holiwyood.'  Calil.  240 

Guy   Simmons.    Jr Conway,  Ark.  250 

James  F.  Boland Fort  Sill.  Okla.  263 

M.  Laurence  Short Hanford",  Calif.  224 

Curtis  Printing  Co Ft.  Worth,  Tex.  246 

Etherical  Radio  Co Bristow  ,Okla.  394 

United  Churches  of  Jlympia Olyrnpia,  Wash.  220 

J.  Gordon  Klemgard Pullman.  Wash.  217 

New  Mexico  College  of  Agriculture  and  Mechanic  Arts,  State  College  N  -M.  266 

The  Electric  Shop Hartington,  Neb.  222 

Angelus  Temple Los  Angeles,    Calif.  272 

The  Van  Blaricon  Co Helena.   Mont.  261 

Hopper  Plumbing  and  Heating  Co Breckenridge    Minn.  242 

Thomas  Goggan  &  Bros.  Music  Co Galveston    Tex.  258 

W.  D.  Corley Colorado  Springs,  Colo.  242 

Concordia     Seminary St.     Louis,     Mo.  549 

Fitzsimmons    General    Hospital Denver,    Colo.  234 

Julius  Brunton  and  Sons  Co San  Francisco,  Calif.  234 

H.  W.  Peery  and  C.  Redfield Ogden,  Utah  224 

Louis    L.    Sherman Oakland.    Calif.  233 

University    of    Utah Salt    Lake    City.    Utah  271 

Colburn    Radio    Labs ; San    Leandro,    Calif..  234 

Irvine    M.    Bouchard Butte,    Mont.  254 

Y.  M.   C.  A Virginia.   Minn.  248 

Bensberg's  Music  Co Camden,  Arkansas  242 

McWhinnie  Electric  Co San  Pedro,  Calif.  205 

Clarence  B.  Juneau Hollywood,    Calif  208 

Whan  Radio  Shop  (Herbert  Whan) Manhattan,  Kansas  218 

Browning  Bros.   Co Ogden,   Utah  214 

Warner  Bros Hollywood,  Calif.  252 

L.  E.  Wall  and  C.  S.  Myers - Upland.  Calif.  211 

Tacoma  Daily  Ledger Tacoma,  Wash.  252 

General  Electric  Co Oakland,  Calif.  361 

Marion    A.    Mulrony Honolulu,    Hawaii,    Waikiki    Beach  360 

Portland  Morning  Oregonian Portland,   Oreg.  491 

St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy,  Wash.  253 

Times-Mirror    Co Los    Angeles,    Calif.  405 

Louis     Wasmer Seattle,     Wash.  273 

C.   O.    Gould Stockton.    Calif.  273 

Northwest  Radio  Service  Co Seattle,  Wash.  384 

Bible  Institute  of  Los  Angeles.  Inc Los  Angeles,  Calif.  293 

Warner   Brothers    Radio   Supplies   Co Oakland,    Calif.  242 

Tribune    Publishing    Co Oakland.    Calif.  508 

Reynolds     Radio     Co Denver,     Colo.  283 

San  Joaquin  Light  &  Power  Corp Fresno,  Calif.  243 

Love    Electric    Co Tacoma,      Wash.  Z5p 

Walter    Hemrich Kukah     Bay.     Alaska  263 

Los  Angeles  Evening  Express Los  Angeles.   Calif.  337 

General   Electric    Co Denver,    Colo.  323 

New  Mexico  College  of  Agriculture  &  Mechanic  Arts  .  State  College,  N.    Mex.  348 

Detroit   Police    Department Detroit,     Mich.  286 

Hale    Bros San    Francisco,     Calif.  428 

Pasadena  Presbyterian  Church Pasadena.    Calif .  229 

Doubleday-Hill     Electric     Co Pittsburgh,      Pa.  270 

Charles    D.    Herrold San    Jose,     Calif.  240 

V.   C.  Battery  &  Electric  Co Berkeley,    Calif.  275 

Kansas  State  Agricultural   College Manhattan,    Kans.  341 

Post  Dispatch   (Pulitzer  Pub.  Co.) St.  Louis     Mo  .  545 

Radio  Service  Corp.  of  Utah Salt  Lake  City,  Utah  299 

New  Arlington  Hotel  Co Hot  Springs,  Ark.  375 

First     Presbyterian      Church Seattle,      Wash.  454 

Examiner  Printing  Co San  Francisco,  Calif.  246 

State   University  of   Montana Missoula.    Montana  244 

Portable    Wireless    Telephone    Co Stockton.    Calif.  360 

Los  Angeles  Examiner Los  Angeles,  Calif.  360 

Electric  Shop Honolulu,  Hawaii  270 

Westinghouse  Electric  &  Mfg.  Co Chicago,  111.  535 

Preston    D.    Allen Oakland.    Calif.  360 

Valdemar  Jensen New    Orleans,    La.  263 

Tulane    University New    Orleans    La.  275 

Ohio  Mechanics  Institute Cincinnati,   Ohio  248 

Chicago  Daily  Drovers  Journal Chicago    III.  286 

I.    R.    Nelson   Co Newark,    N.   J.  263 

University    of    Missouri Columbia,     Mo.  254 

Omaha    Grain    Exchange Omaha,    Nebr. 

Lake   Forest- University Lake  Forest  111., 

Harrisburg    Sporting    Goods    Co Harrisburg,    Pa. 

Lake  Shore   Tire   Co Sandusky,    Ohio 

Bangor  Railway  &  Electric  Co Bangor,  Me. 

Connecticut    Agricultural    College Sorrs,    Conn. 

F.  A.  Doherty  Automotive  and  Radio  Equipment  Co Saginaw,  Mich. 

Ott  Radio,    Inc LaCrosse,    Wis. 

Lake  Avenue  Baptist  Church Rochester,  N.  Y. 


Exchange Omaha,    Nebr.     285 

227 
266 
240 
240 
283 
254 
244 
..  283 

rford   College,   Radio   Club Haverford,   Pa.     261 

High  School,  N.  W.  B.  Foley Toledo,  Ohio     270 

N.  J.  224 
234 
270 
242 
263 
258 


Victor  Talking  Machine  Co Camde:. . 

College  of  Wooster Wooster,  Ohio 

Henry   B.   Joy Mt.    Clemens.    Mich. 

John  Magaldi.  Jr Philadelphia,  Pa. 

Coliseum  Place  Baptist  Church New  Orleans,  La. 

Allen  T.   Simmons   (Allen  Theatre) Akron.  Ohio  _. 

Albert  B.  Parfet  Co Port  Huron,  Mich.  233 

A.  H.  Grebe  &  Co Richmond  Hill.  N.  Y.  315 

Hubbard  and  Co Minneapolis,  Minn.  244 

Purdue    University W.     Lafayette,     Ind.  283 

Clemson  Aerie.   College Clemson   College,   S.   C.  331 

The    Dayton    Co Minneapolis,    Minn.  417 

Wireless  Phone  Corp PaterBon,  N.  J.  244 

James     Millikan     University Decatur.     111.  360 

Wortham-Carter  Publishing  Co.   (Star  Telegram) Fort  Worth,  Tex.  476 

Erner  &  Hopkins  Co Columbus,  Ohio  292 

John  H.  Stenger,  Jr Wilkes-Barre,  Pa.  254 

Western  Electric  Co New  York,   N.  Y.  492 

Irving    Vermilya Mattapoisett,    Mass.  248 

J.  Irving  Bell Port  Huron,  Mich.  246 

Grace    Covenant    Presbyterian    Church Richmond.    Va.  253 

H     Leslie  Atlass Chicago,  111.  226 

Blake.  A.  B Wilmington,  N.  C.  275 

Petoskey  High  School Petoskey,    Mich.  246 

Peoples  Pulpit  Asso RossviUe.  N.  Y.  273 

First  Baptist  Church New  Orleans,    La.  252 

'Jenks    Motor   Sales    Co Monmouth,    111.  224 

Johnstown     Radio     Co Johnstown,     Pa.  245 

Ruffner    Junior    High    School Norfolk,    Va.  222 

Washington  Light  Infantry  Co.   "B"   USth  Inf Charleston,  S.   C.  268 

Noble  B.   Watson Indianapolis,   Ind.  227 

Foster  &  McDoland Chicago.    111.  266 

Baxter  Laundry  Co Grand  Rapids,  Mich.  256 

Bliss  Electrical  School Takoma  Park  Md.  222 

Jones  Elec.  &  Radio  Mfg.  Co Baltimore  Md.  254 

Pennsylvania     State     Police Butler.     Pa.  288 

Baltimore  Radio  Exchange Wilkes-Barre.  Pa.  231 

D.  W.  May,   Inc Newark   N.   J.  252 

Southern   Radio   Corp Charlotte,    N.   C.  275 

Westinghouse  E.  &  M.  Co Springfield,  Mass.  333 

St.    Lawrence    University Canton,    N.    Y.  280 

Kaufmann    &   Baer   Co Pittsburgh,    Pa.  461 

Clyde  R.  Randall New  Orleans.     La.  262 

Entrekin  Electric  Co Columbun,  Ohio  286 

Nebraska  Wesleyan  University University  Place,  Nebr.  283 

St.    O.af    College Northfield.    Minn.  336 

Sanders  &  Stayman  Co Baltimore     Md.  275 

Chesapeake  &  Potoma  Telephone  Co Washington,    D.  C.  468 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


65 


A  Little  Ray  of  Sunshine 
Where  Its  Needed 


"Listen  in!" 

President  A.  J.  Griffin  of  the  Albany 
Park  Kiwanis  club,  Chicago,  is  showing 
one  of  the  Salvation  Army  nurses  and  a 
baby  how  to  run  the  new  radio  set,  a 
gift  to  Salvation  Army's  Women's  Home 
and  Hospital,  5040  N.  Crawford  ave., 
by  the  north-west  Kiwanians. 

The  radio  set  was  presented  at  a 
luncheon  served  recently  in  the  dining 
room  of  the  institution  and  attended  by 
fifty  members  of  the  Kiwanis  club. 
Music  for  the  luncheon  was  furnished  by  a 


part  of  the  Salvation  Army  band.  Com- 
missioner William  Peart  made  the  ad- 
dress of  acceptance.  Before  they  left, 
the  Kiwanians  took  a  trip  of  inspection 
through  the  building. 

The  Women's  Home  and  Hospital,  a 
refuge  for  unfortunate  mothers,  com- 
pleted by  the  Salvation  Army  last  April, 
is  located  on  an  excellent  site  with  woods 
and  a  pretty  neighborhood  about  it. 
The  grounds  of  the  Home  are  being 
improved  and  when  finished  promise  to 
make  the  place  one  of  the  beauty  spots 
of  Chicago. 


"Congress  Classic"  at  KYW 

One  of  the  most  popular  of  the  classic 
type  of  entertainments  put  on  by  Station 
KYW  is  given  each  Saturday  night  at 
the  Congress  Hotel,  Chicago,  where 
KYW  broadcasts  a  good  portion  of  its 
programs. 

The  Congress  Classic,  as  it  is  known 
on  Saturday  nights  from  9:30  to  11:30 
p.  m.,  is  booked  by  Frank  Florentine, 
general  manager  of  the  Congress  Hotel, 
and  is  announced  by  Eddie  Borroff, 
who  also  does  the  announcing  on  the 
Congress  Carnival  which  runs  on  Satur- 
day nights  from  12  to  1  a.  m. 

During  the  week  there  is  dinner  music 
broadcast  from  the  Congress,  made  up  of 
selections  played  by  Joska  DeBabary  and 
his  Continental  quartet,  playing  in  the 
Louis  XVI  room  from  7  to  7:10;  then  a 
journey  to  the  Pompeian  room  to  hear 
the  Coon  and  Sanders  Original  Night- 
hawks  from  7:10  to  7:20,  and  then  back 
to  the  Louis  XVI  room  where  Joska  De- 
Babary finishes  off  with  classical  selec- 
tions from  7:20  to  7:30.  This  concludes 
the  early  broadcasting  from  the  Congress, 
but  at  1  a.  m.,  the  Insomnia  Club  goes 
back  on  the  air  from  the  Balloon  Room, 
Coon  and  Sanders  original  Nighthawks 
playing  until  2  a.  m. 


Free  Sets  for  Slogans 

Radio  sets  with  a  total  value  of  $64,000 
will  be  given  to  fans  all  over  the  United 
States  by  the  All-American  Radio  Cor- 
poration of  Chicago.  The  gifts  will  be 
given  in  return  for  suggestions  for  a  new 
slogan  for  the  corporation's  products. 
All  the  fan  has  to  do  is  to  go  to  his  nearest 
dealer,  get  a  blank  and  fill  it  in  with  his 
name,  address  and  suggestion  for  the 
slogan. 

For  some  time  past,  the  All-American 
has  been  using  the  slogan  "The  Largest 
Selling  Transformer  in  the  World."  The 
production  of  other  lines  of  radio  appar- 
atus, such  as  the  All-Amax  Junior  and 
Senior  semi-finished  sets,  has  made 
necessary  a  change.  The  slogan  should 
apply  to  the  complete  line  of  transform- 
ers, sockets,  semi-finished  sets,  etc. 

Each  dealer  will  award  either  a  Senior 
or  a  Junior  All-Amax  set  to  the  winner. 
The  contest  will  end  the  last  of  April. 

T|   ]N  readers  wish  to  show   their 
J™*    approval  of  RADIO  AGE'S 

stand  against  the  Radio 
Corporation  of  America,  they  can 
do  it  in  the  most  practical  way  by 
sending  in  $2.50  for  a  year's  sub- 
scription or  if  they  are  already  sub- 
scribers, urge  a  friend  to  subscribe. 
We  foelieve  the  fans  are  with  us. 
Address   Radio   Age,    Inc. 

*     Tested  and  Approved  by  RADIO  AGE     * 


Matched  Sets 

for  Uniform 
Dial  Settings! 

This  most  recent  Duplex  achieve- 
ment— Duplex  Standard  conden- 
sers, specially  tested,  matched  and 
guaranteed  to  have  identical  capa- 
city curves,  packed  in  sealed  kits 
of  three — has  been  enthusiastically 
welcomed  everywhere  by  radio  set 
builders,  both  professional  and 
amateur.  It  is  the  only  kit  that 
affords  uniform  dial  settings  for 
Neutrodynes  and  all  other  tuned 
radio  frequency  circuits.  Only  one 
number  to  log — not  three — when 
you  use  a  Duplex  Matched  Kit! 
Folders  telling  how  to  make  tuning 
easier  and  reception  better  sent  free 
on  request. 

Duplex  Condenser  &  Radio  Corp. 

42  Flatbush  Ave.  Extension 

Brooklyn,  New  York 


66 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


WCAR      Alamo  Radio  Electric  Co San  Antonio,  Tex.     263 

WCAS        W.  H.  Dunwoody  Industrial  Institute Minneapolis,  Minn.     280 

WCAT^     State  College  of  Mines Rapid  City    S.  Dak.     240 

WCAU       Durham    &    Co Philadelphia.    Pa.      278 

WCAV       J.    C.   Dice   Electric   Co Little   Rock.   Ark.      263 

WCAX      Unversity    of    Vermont Burlington,    Vt.     2S0 

WCAZ       Carthage    College Carthage.    111.     246 

WCBA       Charles  W.  Heihachm Allentown,  Pa.      280 

WCBC       University   of   Michigan Ann   Arbor,    Mich.     280 

WGBD      Wilbur     C.     Voliva Zion      111.     344 

WCBE       Uhalt    Radio-  Co New    Orleans,    La.     263 

WCBF       Paul    J.    Miller Pittsburgh,    Pa.     236 

WCBG       Howard    S.    Williams     (Portable) Pascagoula,    Miss.     268 

WCBH      University    of    Miss Oxford,    Miss.     242 

WCBI         Nicoll,     Duncan    &    Rush Bemis,    Tennessee     240 

WCBJ        J.   C.   Maus Jennings,   Louisiana     244 

WCBL       Northern      Radio     Mfg.      Co Houlton,      Mo.     280 

WCBM      Charles     Swarz Baltimore,     Md.     229 

WCBN       James   P.   Boland Ft.   Benj.   Harrison.   Ind.      266 

WCBO       The   Radio   Shop.   Inc Memphis,   Tenn.      250 

WCBQ       First    Baptist    Church Nashville,    Tenn.     236 

WCBR       C.  H.  Messter Providence,  R.  I.      246 

WCBT       Clark    University,    Collegiate    Dept Worcester.    Mass.      238 

WCBU      Arnold     Wireless     Supply     Co Arnold,     Pa.     254 

WCBV      Tullahoma  Radio  Club Tullahoma.  Tenn.     252 

WCBW      George   P.   Rankin.  Jr.,   and   Maitland   Solomon Macon,   Ga.     226 

WCBX       Radio   Shop  of  Newark   (Herman  Lubinsky") Newark.   N.  J.     233 

WCB Y      The  Forks   Eectrical   Shop Buck   Hill   Falls.   Pa.     268 

WCBZ        Coppotelli  Bros.  Music  House Chicago  Heights.  111.     248 

WCCO       Washburn-Crosby    Co ; Twin    Cities.    Minn.     416 

WCEE        Charles    E.    Erbstein.    Villa    Olivia near    Elgin.    111.     278 

WCK         Stix-Baer- Fuller    D.    G.    Co St.    Louis,    Mo.     275 

WCX  Free       Press Detroit.       Mich.     516 

WDAE       Tampa      Daily      Times Tampa,      Fla.     365 

WDAF      Kansas    City    Star Kansas    City.    Mo.     365 

WDAG      J.    Laurence    Martin Amarillo,    Tex.     263 

WDAH     Trinity     Methodist     Church     (South) El     Paso,     Tex.     268 

WDAR       Lit  Brothers Philadelphia,  Pa.     394 

WDAY      Radio    Equipment    Corp Fargo.    N.    Dak.     244 

WDBA      Fred       Ray Columbus,       Ga.     236 

WDBB      A.  II.  Waite  &  Co.,  Inc Taunton.  Mass.     229 

WDBC      Kirk,    Johnson    &    Co Lancaster.    Pa.     258 

WDBD      Herman  Edwin  Burns Martinsburg.  W.  Va.     268 

WDBE       Gilham-Schoen    Elec.     Co Atlantic,     Ga.     278 

WDBF      Robert  G.   Phillips .Youngstwn,     Ohio     315 

WDBH      C.   T.   Scherer   Co Worcester,   Mass.     268 

WD8I        Radio    Specialty    Co St.    Petersburg,    Fla.     226 

WDBJ        Richardson      Wayland      Electric      Corp Roanoke,      Va.     229 

WDBL      Wise.    Dept.    of    Markets Stevens    Point,    Wis.     278 

WDBN      Electric    Light  &  Power    Co Bangor,    Me.     252 

WDBO      Rollins    College    Inc Winter    Park,    Fla.     240 

WDBP      Superior     State     Normal     School Superior,     Wis.     261 

WDBQ      Morton    Rado    Supply    Co Salem,    N.    J.     234 

WDBR       Tremont    Temp.e    Baptist    Church Boston,    Mass.      256 

WDBS       S.   M.   K.   Radio   Corp Dayton,   Ohio     283 

WDBT      Taylor    Book    Store Hattiesburg,    Miss.     236 

WDBV      The     Strand     Theatre Fort     Wayne,     Ind.     258 

WDBW     The   Radio   Den Columbia,   Tenn.     268 

WDBX      Otto  Baur New  York,  N.  Y.     233 

WDB  Y      North    Shore    Congregational    Church Chicago.    111.     258 

WDBZ       Boy  Scouts,   City  Hall .Kingstown,  N.  Y.      233 

WDM         Church   of  the   Covenant Washington,    D,    C.     234 

WDWF      Cranston.      R.     I.     440 

WDZ         J.    L.    Bush Tuscola.    III.     278 

WEAA       F.     D.    Fallain Flint.    Mich.     250 

WEAF       American  Telephone  &  Telegraph  Co New  York.  N.  Y.      485 

WEAH       Wichita    Board   of   Trade Wichita,    Kans.     280 

WEAI         Cornell     University Ithaca.     N.     Y.      286 

WEAJ        University  of  South   Dakota Vermilion,  S.  Dak.      283 

WEAM  Borough  of  North  Plainfield  <W.  Gibson  Buttfield)  ..  North  Plainfleld,  N.  J.     286 

WEAN      Shepard    Co Providence,    R.    I.     273 

WEAO       Ohio    State    University Columbus,    Ohio     293 

WEAP       Mobile      Radio      Co Mobile.      Ala.     263 

WEAR       Goodyear    Tire    and    Rubber    Co Cleveland.    Ohio     389 

WEAU       Davidson    Bros.  Co Sioux    City.    Iowa     275 

WEA  Y       Iris     Theatre     (Will     Horowitz.    Jr.) Houston.     Texas     360 

WEB  Benwood     Co St.     Louis.     Mo.      273 

WEBA       Electric  Shop Highland  Park,   N.  J.     233 

WEBC       Walter     Cecil     Bridges Superior.      Wis.     242 

WEBD       Electrical   Equipment  and   Service  Co Anderson,   Ind.      246 

WEBE        Roy     W.     Walker Cambridge.     Ohio     248 

WEBH       Edgewater  Beach  Hotel,  Chicago  Evening  Post  Station Chicago,     III.     370 

WEBJ        Third  Avenue  Railway  Co New  York.    N.  Y.      273 

WEBM      Radio     Corporation     of    America Portable     226 

WEBP       E.    B.    Pedicord New    Orleans,    La.     280 

WEBT       The   Dayton    Coop.   Industrial  High  School Dayton.  Ohio     270 

WEBW      Beloit     College Beloit     Wis.     283 

WEBX       John    E.    Cain,    Jr Nashville.    Tenn.      263 

WEB  Y       Hobart     Radio    Co Roslindale.     Mass.      226 

WEE1         The  Edison  Electric  Illuminating  Co Boston.  Mass.      475 

WEMC       Barrien     Springs.     Mich.     285 

WEW        St.    Louis    University St.    Louis,    Mo.     280 

WFAA        Dallas     News    &    Dallas    Journal Dallas,    Tex.      472 

WFAM     Times  Publishing  Co St.  Cloud.  Minn.     273 

WFAV  University  of  Nebraska,  Department  of  Electrical  Engineering,  Lincoln,  Nebr.      275 

WFBB       Eureka     College Eureka.    HI.     240 

WFBC       First     Bapitist     Church Knoxvilte.     Tenn.     250 

WFBD       Gethsemane  Baptist  Church Philadelphia.  Pa.     234 

WFBE       John     Van     De     Walle Seymour,     Ind.     226 

WFBD       Gethsmane  Baptist  Church Philadelphia.  Pa.     234 

WFBE       John     Van      De     Walle Saeymour,     Ind.     226 

WFBG      The  Wm.  F.   Cable  Co Altoona.   Pa.     261 

WFBH      Concourse    Radio    Coporation New    York,    N.    Y.     273 

WFBJ       St  John's    University Collegeville,     Minn.     236 

WFBQ      Wynne    Radio    Co Raleigh.    N.    C.     255 

WFBR       Fifth  Inf.  Md.  Nat"  Guard.  5th  Reg.  Armory Baltimore.  Md.     452 

WFBT       Gloucester    Co..    Civic    League Pitman.    N.    J.     231 

WFBW     Ainsworth-Gates     Radio     Co Cincinnati.     Ohio     309 

WFB  Y       Signal     Officer Ft.     Ben     Harrison,     Ind.      258 

WFBZ        Knox       College Galesburg.       HI.     254 

WFI  Strawbridge  and   Clothier Philadelphia,  Pa.      394 

WFUV       G.     Pearson     Ward Springfield.     Mo.      252 

WFUW     Earl  William   Lewis Moberly.   Mo.     233 

WGAL       Lancaster  Electric  Supply  &  Construction  Co Lancaster.  Pa.     248 

WG  AQ      Youree     Hotel Shreveport.     La.     252 

WGAZ      South  Bend  Tribune South  Bend,  Ind.     360 

WGBB       Harry  H.  Carman.  217  Bedell  St Freeport.  N.  V.     244 

WGBC       First   Baptist    Church Memphis.   Tenn.      266 

WGBF       Fink    Furniture    Co Evansville.    Tnd.     217 

WGBG      Brietenbach's    Radio   Shop Thrifton,   Va.     226 

WGBH      Fall   River   Herald  Pub.  Co (Portable)      209 

WGBI        Frank     S.     Megargee Scranton,     Pa.     240 

WGBK      Lawrence      Campbell Johnstown,      Pa.     248 

WGBM     Theodore    N.    Saaty Providence.    R.    I.     234 

WGBN      Hub     Radio     Shop LaSalle.     111.     266 

WCBO      Dr.   Roses   Artan San  Juan,   P.   R.     275 

WGBP      M.    L.    Price   Music   Co Tampa,  Fla.     250 

WGBL       Elyria  Radio  Asso.  (Albert  H.  Ernst) Elyria,  Ohio     227 

WCBQ      Stout  Institute Menominee,  Wis.     234 

WGBR      Marshfield  Broadcasting  Assn Marshfield.  Wis.     229 

WGBS       Gimbel  Brothers New  York,  N.  Y".      315 

WGBT      Furman     University Greenville,    S.     C.     236 

WGBW     Valley    Theater Spring    Valley.     IU.     212 

WGBX      University  of  Main Orono,  Me.     252 

WGB  Y      Progress  Sales  Co R.  R.  No.  2     218 

WGI  American  R.  &  R.  Co Medford  Hillside.  Mass.     261 

WGN  The    Tribune    Co Chicago,    HI.     370 

WGR         Federal  T.  and  T.  Co Buffalo.  N.  Y.     319 

WGY        General   Elec.    Co Schenectady  N.  Y.     379 

WHA         University    of    Wisconsin Madison,    Wis.     535 

WHAD      Marquette  University Milwaukee,  Wis.      280 

WHAG      University   of   Cincinnati Cincinnati,   Ohio     222 

WHAH      Hafer  Supply  Co ■ Joplin.  Mo.     283 

WHAM     University  of  Rochester   (Eastman  School  of  Music) Rochester.  N.  Y.     278 


WHAP      H.  Alvin  Simmons,  290  Flatbush  Ave Brooklyn  N.  Y      240 

vJIHA5      Seaside  House Atlantic  City,  N.  J.     275 

WHAS  Courier-Journal  &  Louisville  Times Louisville     Ky       399 

WHAV       Wilmington  Electrical  Specialty  Co Wilmington,   Del.     360 

WHAZ       Rensselaer  Polytechnic    Institute Troy,   N.  Y.     385 

WHB         Sweeney    School    Co Kansas    City     Mo      365 

WHBA      C.  C.  Shaffer Oil  City,  Pa.     250 

WHBB      Hobel's  Store Stevens  Point,  Wis.     240 

WHBC      Rev.  E.  P.  Graham Canton,  Ohio     245 

WHBD      Chas.  W.  Howard Bellefontaine.  Ohio     222 

WHBF       Beardsley  Specialty  Company Rock  Island.  Illinois     222 

WHBG      John    S.    Skane Harrisburg,    Pa.     231 

WHBH      Culver    Military    Academy Culver,     Ind.     222 

WHBI        Chesaning    Electric    Co Chesaning      Mich       227 

^H5i  t?uer  Auto  Co Ft-  Wayne,  Ind.     234 

WHBK      Franklin    St.    Garage.   Inc Ellsworth,    Maine     231 

SHIK     J«njes  H.  grosser Logansport.  Ind.     220 

WHBM     C.  L.  Carroll.  Portable  Station Chicago    III.     233 

WHBN       First   Ave.    Methodist   Church St.   Petersburg     Florida     258 

WHBO      Y".  M.  C.  A.,  Summer  Street Pawtucket,  Rhode  Island     231 

WHBP  Johnstown  Automobile  Co Johsntown,  Pennsylvania     256 

WHBQ      St.  Johns  M.  E.  Church  South Memphis    Tenn.     233 

WHBR  Scientific  Electric  <fc  Mfg.  Co..  3664  Vine  St Cincinnati.  Ohio     216 

WHBS  Edward  Wm.  Locke Mechaxticsburg   Qhio     208 

WHBT  Thomas  W.  Tizzard,  Jr Downers  Grove.   HI.  206 

WHBU  B.    L.   Bing's   Sons Anderson,   Ind.      218 

WHBW     D.     R.    Kienzle Philadelphia,    Pa..      215 

WHEC  Hickson  Electric  Co..  Inc Rochester.  N.  Y.     258 

WHK  Radiovox  Company Cleveland,  Ohio     273 

WHN  George  Schubert New  York,  N.  Y.     360 

WHO  Bankers' Life  Co Des     Moines,     la.     526 

WIAD  Howard   R.   Miller Philadelphia.   Pa.     254 

WIAK  Journal-Stockman  Co Omaha,  Nebr.     273 

WIAQ  Chronicle     Publishing    Co Marion.     Ind.     226 

WI AS  Home  Electric  Co Burlington.  Iowa     283 

WIBA  The    Capital    Times-Studio Madison,    Wis.     236 

WIK  K.  &  L.  Co McKeesport,  Pa.     234 

WIL  Continental  Electric  Supply  Co Washington,  D.  C.     360 

WIP  Gimbel    Bros Philadelphia,    Pa.      509 

WJAB  American    Electric    Co Lincoln,    Nebr.     229 

WJAD  Jackson's    Radio   Engineering   Laboratories Waco.    Texas     352 

WJAG  Norfolk    Daily   News Norfolk,    Nebr.     283 

WJAK  Clifford    L.    White Greentown.    Iowa     254 

WJAM  D.  M.  Perham Cedar  Rapids,  Iowa     268 

WJAN  Peoria     Star Peoria.     III.     280 

WJAR  The  Outlet  Co.  (J.  Samuels  &  Bro.) Providence,  R.  I.      305 

WJAS  Pittsburgh  Radio  Supply  House Pittsburgh,    Pa.     286 

WJ AZ  Chicago    Radio    Laboratory Chicago.    HI.     268 

WJD  Denison    University Graniteville.    Ohio     229 

WJJD  Supnme  Lodge.  Loyal  Order  of  Moose Mooseheart,  HI.     303 

WJY  Radio  Corp.  of  Ama New  York.  N.  Y.     455 

WJZ  Radio  Corp.  of  Ama New  York,  N.  Y.     455 

WKAA  H.    F.    Paar Cedar   Rapids,   Iowa     278 

WKAD  Chas.   LoofI  (Crescent  Park) East  Providence.  R.  I.     240 

WK  AN  United     Battery    Service     Co Montgomery,     Ala.     226 

WKAP  Dutee    W.     Flint Cranston,    R.    I.     234 

WKAQ  Radio  Corp.  of  Porto  Rico San  Juan,  P.  R.      340 

WKAR  Michigan    Agriculture     College East     Lansing,     Mich.     285 

WKAV  Laconia    Radio    Club Laconia,    N.    H.     254 

WKBE  K.  i  B.  Electric  Co Webster.  Massachusetts     231 

WKBF  Dutee  Wilcox  Flint Cransten,  Rhode  Island     286 

WK.Y  Wky   Radio  shop Okla.   City,    Okla.     275 

WLAG  Cutting  i  Washington  Radio  Corp Minneapolis,  Minn.      417 

WLAL  First   Christian  Church Tulsa.   Okla.     250 

WLAP  Wm.     V.    Jordan Louisville,     Ky.     286 

WLAQ  Arthur  E.  Shilling Kalamazoo,  Mich.     283 

WLAX  Putnam      Electric      Co Grcencastle,      Ind.     231 

WLB  University   of   Minnesota Minneapolis,    Minn.     278 

WLBL  Wisconsin   State   Dept.  of   Markets Stevenspoint.   Wis.     278 

WLS  Sears    Roebuck    &    Co.. Chicago,    IU.      344 

WLW  Crosley     Mfg.     Co Cincinnati,     Ohio     422 

WMAC  J.  Edw.  Page  (Olive  B.  Meredith Cazenovia.  N.  Y.     261 

WMAF  Round    Hills    Radio    Corp Dartmouth,    Mass.     360 

WMAH  General     Supply     Co Lincoln,     Nebr.     254 

WMAK  Norton      Laboratories Lockport.      N.      Y.     273 

WMAL  Trenton    Hardware   Co Trenton,    N.    J,     256 

WMAN  First    Baptist    Church Columbus,    Ohio     286 

WMAQ  Chicago     Daily    News Chicago,     HI.     447 

WMAV  Alabama    Polytechnic    Institute Auburn,    Ala.     250 

WMAY  King-highway    Presbyterian    Church St.    Louis,    Mo.     280 

WMAZ  Mercer    University Macon,    Ga.     261 

WMBF  Miami    Beach,    Fla.     384 

WMC  Commercial     Appeal Memphis.     Tenn.      503 

WMH  Ainsworth-Gates    Radio    Co Cincinnati,    O.      321 

WMU  Doubledal-Hill   Elec.   Co Washington.    D.    C.     260 

WNAC  Shepard       Stores Boston,       Mass.     284 

WNAD  University   of    Oklahoma Norman,    Okla.      258 

WN AL  Omaha    Central    High    School Omaha.    Nebr.     255 

WNAP  Wittenberg  College Springfield,  Ohio     271 

WNAR  First    Ch-istian    Church Butler.    Mo.      230 

WNAT  Lennig  Brothers  Co.  (Frederick  Lennig) Philadelphia.  Pa.      254 

WNAX  Dakota   Radio  Apparatus   Co Yankton,   S.   Dak.      248 

WNYC  Dept.  of  Plant  and  Structures New  York,  N.  Y.     526 

WOAC  Page     Organ     Co Lima.     Ohio     260 

WOAE  Midland   College Fremont.  Nebr.     280 

WOAF  Tyler    Commercial    College Tyler.    Texas     363 

WOAG  Apollo     Theater     (Belvidere    Amusement     Co.) Belvidere.     IU.     274 

WOAI  Southern  Equipment  Co San  Antonio.  Texas     392 

WOAN  Vaughn  Conservatory  of  Music  (James  D.  Vaughn) ....  Lawrenceburg,  Tenn.     280 

WOAO  Lyradion    Mfg.    Co Mishawaka,    Ind.     369 

WOAR  Lundskow.  Henry  P Kenosha,  Wis.     225 

WOAT  Boyd      M.      Hamn Wilmington,      Del.     360 

WOAV  Pennsylvania    National    Guard.    2d   Battalion.    112th    Infantry Erie,    Pa.     242 

WOAW  Woodmen   of  the   World Omaha.   Nebraska      526 

WOAX  Franklyn     J.     Wolff Trenton,     N.     J.     240 

WOC  Palmer    School    of    Chiropractic Davenport,    Iowa     484 

WOCL  Hotel   Jamestown,    Inc Jamestown,    N.   Y.     275 

WOI  Iowa      State      CoUege Ames.      la.     207 

WOO  John    Wanamaker Philadelphia.    Pa.      509 

WOR  L.   Bamberger  and   Co Newark.   N.   J.     405 

WORD  Peoples     Pulpit    As-sn Batavia,     HI.     275 

WOS  State    Marketing    Bureau Jefferson     City,     Mo.      440 

WPAB  Pennsylvania     State     College State     CoUege.     Pa.     283 

WPAC  Donaldson    Radio    Co Okmulgee,    Okla.     360 

WPAJ  Doolittlc   Radio   Corp New  Haven,  Conn.     268 

WPAK  North  Dakota  Agricultural   College Agricultural  CoUege.  N.  D.      283 

WPAL  Superior   Radio  &   Telephone   Equipment  Co Columbus,   Ohio     286 

WPAU  Concordia      CoUege Moorehead,      Minn.     286 

WPAZ  John    R.    Koch    (Dr.l Charleston.    W.    Va.     273 

WPG  The  Municipality  of  Atlantic  City Atlantic  City.  N.  J.     300 

WQAA  Horace    A.    Beale,    Jr Parkersburg.    Pa.     270 

WQAC  E.      B.      Gish Amarulo,      Texas     234 

WOAE  Moore  Radio  News  Station   (Edmund  B.  Moore) Springfield,  Vt.     275 

WQAM  Electrical     Equipment     Co Miami.     Fla.     283 

WQAN  Scranton     Times Scranton.     Pa.     280 

WQAO  Calvary  Baptist  Church New  Y'ork,  N.  Y.     360 

WQAS  Prince-Walter       Co LoweU.       Mass.     266 

WQJ  Calumet     Rainbo     Broadcasting     Co Chicago.     HI.     447 

WRAA  The      Rice      Institute Houston.      Tex.     256 

WRAF  The     Radio     Club     (Inc.) Laporte,     Ind.      224 

WRAK  Economy    Light    Co Escanaba.    Mich.      256 

WRAM  Lombard     College Galesburg,     III.     244 

WRAN  Black     Hawk     Electrical     Co Waterloo.     Iowa     236 

WRAO  St.    Louis    Radio   Service   Co St.   Louis,    Mo.     263 

WRAV  Antioch      College. Yellow      Springs.      Ohio     242 

WR AW  Avenue   Radio   Shop    (Horace   D.   Good) Reading.    Pa.     238 

WRAX  Flaxon's     Garage Gloucester     City.     N.     J.     268 

WRBC  Imanuel   Lutheran   Church Valparaiso.  Ind.     278 

WRC  Radio  Corp.  of  Ama Washington,  D.  C.     468 

WREO  Reo    Motor    Car    Co Lansing.    Mich.     286 

WRHF  Washington   Radio   Hospital   Fund Washington.  D.  C.      256 

WRK  Doron      Bros Hamilton.      Ohio     360 

WRL  Union  College Schenectady.  N.  Y.     270 

WRM  University      of      Illinois Urbana.      HI.     273 

WRR  Police    and     Fire     Signal     Department Dallas.     Tex.     261 


RADIO  AGE  for  May,  1925 

Where  the  HOWLS  Come 
From 

(Continued  from  page  8) 


No  great  trouble  is  experienced  here, 
unless  the  amplification  is  carried  too 
far.  Usually  two  stages  will  suffice 
and  if  more  are  added,  the  tube  noises, 
static  and  vibrations  of  the  set  are  so 
magnified  that  the  clearness  of  reception 
is  impossible,  although  some  set  manu- 
facturers have  succeeded  in  so  carefully 
balancing  their  circuits  that  three  stages 
are  used  in  some  cases. 

There  are  two  popular  methods  of 
obtaining  audio  frequency  amplification, 
both  of  which  have  their  advantages  and 
disadvantages.  One  is  the  transformer 
coupled  type  and  the  other  is  the  resist- 
ance coupled  arrangement,  and  at  this 
time  there  is  considerable  talk  about 
which  is  the  better  of  the  two.  In 
resistance  coupled  amplification,  very 
high  resistances  are  used  between  the 
plate  battery  and  the  plate,  which  makes 
it  necessary  to  use  extremely  high  voltages 
on  the  plate  circuits.  It  is  not  uncommon 
to  use  from  150  to  300  volts,  according 
to  the  amount  of  resistance  used.  This 
high  pressure  is  necessary  in  order  to 
force  the  proper  amount  of  plate  current 
through  the  high  resistance. 

In  this  case  there  is  no  amplification 
with  the  exception  of  that  due  to  the 
tube,  and  in  order  to  get  any  great 
amount  of  volume,  more  stages  must  be 
used  than  would  be  necessary  with 
transformer  amplification.  With  more 
tubes,  we  are  sure  to  find  more  tube 
noises  in  the  final  stage. 

Taking  for  example  a  two  stage  resist- 
ance coupled  amplifier,  using  the  stand- 
ard UV-201-A  tubes  with  an  amplification 
constant  of  approximately  8,  we  would 
have  8x8,  or  roughly  speaking,  an 
amplification  of  64,  while  with  a  two- 
stage,  transformer  coupled  amplifier 
using  transformers  having  a  ratio  of  4  to 
1,  we  would  have  8x4x8x4,  or  1024. 
In  this  case,  also,  much  less  plate 
voltage    would    be      required     to      pro- 


duce this  great  difference  in  amplification 
value.  It  is  claimed  by  many  that 
resistance  coupled  amplification  is  better, 
because  there  will  be  no  distortion, 
but  there  is  more  or  less  distortion 
every  time  the  signal  is  passed  through 
a  tube  and  there  is  no  reason  why  a 
carefully  designed  transformer  should 
increase  this  distortion,  although  it  is 
true  that  because  of  the  greater  amplifi- 
cation afforded  by  the  transformer 
method,  the  inherent  noises  from  the 
tubes  and  other  sources  will  be  amplified 
in  proportion  to  the  signal  amplification. 
For  this  reason  we  may  get  the  im- 
pression of  more  distortion.  The  original 
cost  of  installation  of  the  resistance 
type  is  necessarily  greater,  due  to  the 
fact  that  more  tubes,  sockets  and  bat- 
teries are  required  to  get  the  same  volume 
which  may  be  obtained  by  the  trans- 
former  arrangement. 


Amateurs  Get  New  Waves 
Secretary  Hoover  today  authorized 
the  amateurs  to  use  waves  less  than  one 
meter  in  length  in  addition  to  their 
previous  assignment.  The  permission 
covers  the  channels  between  .7477  and 
.7496  of  a  meter,  in  other  words,  a  band 
at  about  the  3-4  meter  wavelength. 
Few  people  realize  the  immense  number 
of  possible  operating  channels  that  lie 
in  the  low  wavelengths.  While  the 
band  now  assigned  to  amateurs  is  only 
nineteen  one-thousandths  of  one  meter 
in  width,  its  extremes  are  separated 
by  one  thousand  kilocycles.  The  secre- 
tary pointed  out  that  if  it  ever  became 
feasible  to  conduct  broadcasting  on 
these  frequencies,  it  would  be  possible 
to  place  within  this  band  100  broad- 
casting stations  and  give  'to  each  the 
present  separation  of  ten  kilocycles, 
and  said  further  that  all  the  stations 
in  the  world  could  operate  in  the  upper 
half  of  the  one  meter  band.  The  art 
has,  of  course,  not  developed  to  make 
this  possible,  but  the  amateurs  now 
have  an  opportunity  to  see  what  they 
can   do. 


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RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


WRW  Tarrytown    Radio    Res.    Laba Tarrytown,    N.    Y. 

WSAB  Southeast  Missouri  State  Teachers  College Cape  Girardeau.  Mo. 

WSAC  Clenison   Agricultural   College Clemson   College,   S     C. 

WSAD  J.     A.     Foster    Co Providence.     R.     I. 

WSAG  Loren     Vanderbeck     Davis St.     Petersburg,     Fla. 

WSAI  United    States    Playing    Cards   Co Cincinnati.    Ohio 

WSAJ  Grove     City     College Grove     City,     Pa. 

WSAN  AUentown    Call    Publishing    Co Allentown,    Pa. 

WSAP  Seventh  Day  Adventist  Church New  York,  N.  Y. 

WSAR  Doughty    &    Welch    Electrical    Co Fall    River,    Mass. 

WSAU  Camp    Marienfeld Chesham.    N.    H. 

WSAV  C.    "W.    Vick    Radio    Construction    Co Houston.    Tex. 

WSAY  Irving  Austin  (Port  Chester  Chamber  of  Commerce)-  .Port  Chester.  N.  Y. 

WSAZ  Chas.     Electric     Shop Pomeroy.     Ohio 

WSE  Atlanta      Journal Allanta,       Go 

WSL  J.  and   M.  E!ec.   Co Utica.   NY. 

VVSMH  Shattuck  Music  House Owosso,  Mich. 

WSOE  School    of    Engineering Milwaukee.    Wis. 

WSRF  nardem    Sales    and    Service Broadlands.    HI. 

WSUI  State    University    of    Iowa Iowa    City.    Iowa 

WTAB  Fall  River  Daily  Herald  Publishing  Co Fall  River.   Mass. 

WTAC  Penn      Traffic      Co Johnstown.       Pa. 

WTAF  Louis    J.    Gallo New     Orleans.     La. 


273 

WTAL 

275 

WTAM 

336 

WTAP 

261 

WTAQ 

264 

WTAR 

325 

WTAS 

258 

WTAT 

229 

WTAU 

263 

WTAW 

254 

WTAX 

229 

WTAY 

360 

WTAZ 

233 

WTHS 

258 

WTG 

428 

WTIC 

273 

WTX 

240 

WWAD 

246 

WWAE 

233 

WW  I 

498 

WWJ 

248 

WWL 

360 

WWOA 

242 

Toledo  Radio  &  Electric  Co Toledo.  Ohio  252 

Willard  Storage  Battery  Co Cleveland,  Ohio  389 

Cambridge  Radio  &  Electric  Co Cambridge,  111.  242 

S.  H.  Van  Gordon  &  Son Osseo.  Wia.  220 

Reliance    Electric    Co Norfolk.    Va.  280 

Charles   E.   Erbstein Elgin,   111.  303 

Edison  Electric   Illuminating  Co Boston,   Mass,   (portable)  244 

Ruegg  Battery  &  Electric  Co Tecumseh.  Nebr.  242 

Agricultural  &  Mechanical  College  of  Texas College  Station,  Tex.  280 

Williams    Hardware    Co Streator,     111.  231 

Oak  Leaves  Broadcastng  Station Oak  Park.  III.  283 

Thomas   J.   McGuire Lambertville,    IST.   J.  283 

Flint    Senior    High    School Flint.    Mich.  218 

Kansas  State  Agricultural  College Manhattan,  Kans.  273 

Travelers  Insurance  Co Hartford,  Conn.  323 

H.  G.  Saal  Co Chicago,  111.  268 

Wright  &  Wright  (Inc.)  ...-..* Philadelphia,  Pa.  360 

The  Alamo  Ball  Room Joliet.  HI.  242 

Ford    Motor   Co Dearborn,   Mich .  273 

Detroit    News     (Evening    News    Assn.) Detroit.     Mich.  "52 

Loyola    University New    Orleans.     La.  ?60 

Michigan  College  of  Mines; Houghton,  Mich.  244 


Canadian  Stations 


CFAC 

CFCA 

CFCF 

CFCH 

CFCJ 

CFCK 

CFCN 

CFCQ 

CFCR 

CFCT 

CFCU 

CFCW 

CFDC 

CFHC 

CFLC 

CFQC 

CFRC 

CFUC 

CFXC 

CFYC 

CHAC 

CHBC 

CHCB 

CHCD 

CHCE 

CHCL 

CHCM 

CHCS 

CHIC 

CHNC 


Calgary    Herald Calgary.    Alberta  430 

Star  Pub.  4  Prtg.  Co Toronto.  Ontario  400 

Marconi  Wireless  Teleg.  Co.  Canada Montreal.  Quebec  440 

Abitibi  Power  &  Paper  Co Iroquois  Falls,  Ont.  400 

La  Cie  de  L'Evenement Quebec,  Quebec  410 

Radio   Supply   Co Edmonton,   Alberta  410 

W.  W.  Grant  Radio  (Ltd.) Calgary,  Alberta  440 

Radio  Specialties    (Ltd.) Vancouver,   B.C.  450 

Laurentide   Air    Service Sudbury.    Ont.  410 

Victoria   City  Temple Victoria,    British,    Col.  410 

The  Jack  Elliott  Radio  Limited ■  .Hamilton.  Ont.  410 

The  Radio  Shop London,    Ont.  420 

Sparks    Co Nanaimo.    B.    C.  430 

Henry  Birks   &  Sons Calgary.  Alta.  440 

Chas    Guy  Hunter 551  Adelaide  St.,   London.   Ont.  410 

The  Electric  Shop   (Ltd.) Saskatoon.   Saskatchewan  400 

Queens     University Kingston,     Ontario  450 

University   of    Montreal Montreal.    Quebec  400 

Westminster  Trust  Co New  Westminster.   B.   C.  440 

Victor   Wentworth    Odium Vancouver.   B.    C.  400 

Radio    Engineers Halifax.    Nova    Scotia  400 

Albertan  Publishing  Co Calgary.  Alberta  410 

Marconi    Company Toronto.    Ont.  410 

Canadian  Wireless  &  Elec.  Co Quebec.  Quebec  410 

Western  Canada  Radio  Sup.  (Ltd.) Victoria,  B.  C.  400 

Vancouver  Merchants  Exchange Vancouver.  B.  C.  440 

Piley  &  McCormack Calgary,  Alberta  415 

The   Hamilton   Spectator Hamilton.   Ont.  420 

Northern    Electric    Co Toronto.    Ont.  356 

Toronto     Radio     Research Toronto.     Ont.  350 


CHXC  J.    R.    Booth Ottawa.    Ont.  435 

CHYC  Northern  Electric  Co Montreal.  Quebec  410 

CJBC  Jarvis  Baptist  Church Toronto.   Ont.  312 

CJCA  Edmonton  Journal Edmonton.  Alberta  455 

CJCC  London  Free  Press  Prtg.  Co London,  Ont.  430 

CJCD  T.    Eaton    Co Toronto.    Ont.  410 

CJCE  Snrott-Shaw    Radio    Co Vancouver.    B.    C.  420 

CJCF  The    News    Record Kitchener.    Ont.  295 

CJCI  Maritime  Radio  Corp St.  John.   New  Brunswick  400 

CJCK  Radio  Corp.  of  Calgary Calgary,  Alta.  316 

CJCM  J.  L.  Phillipe Mont  Joli,  Queboo  430 

CJCN  Simons  Agnew  &  Co Toronto.  Ont.  410 

CJSC  Evening    Telegram Toronto,     Ont.  430 

CKAC  La  Presse  Pub.  Co Montreal.  Quebec  430 

CKCD  Vancouver  Daily  Province Vancouver.    B.  C.  410 

CKCE  Canadian  Indcpcnd.  Telephone  Co Toronto,  Ont.  450 

CKCK  Leader    Pub.    Co Regina,    Saskatchewan  420 

CKCO  Ottawa    Radio    Association. Ottawa,    Ont.  440 

CKCX  P.  Burns  &  Co Calgary,  Alberta  440 

CKLC  Wilkinson   Electric   Company Calgary,   Alberta  400 

CKOC  Wentworth    Radio   Supply   Co Hamilton,    Ont.  410 

CNRA  Canadian  National  Railways Moncton.  N.  B.  313 

CNRC  Canadian  National  Railways Calvary.  Canada  357 

CNRE  Canadian  National  Railways Edmonton.  Alta.  455 

CNRM  Canadian  National  Railways Montreal,  P.  Q.  410 

CNRO  Canadian  National  Railways Ottawa,  Ont.  430 

CNRR  Canadian  National  Railways Regina,  Sash.  312 

CNRS  Canadian  National  Railways Saskatoon,  Sash.  329 

CNRT  Canadian  National  Railways Toronto.  Ont.  357 

CNRW  Canadian  National  Railways Winnipeg,  Man.  384 


Cuban  Stations 


PWX 

2DW 

2AB 

20K 

2BY 

2CX 

2EV 

2TW 

2HC 

2LC 

2KD 

2MN 

2MG 

2JD 


Cuban  Telephon   Co Habana 

Pedro  Zayas Habana 

Alberto  S.  de  Bustamante Habana 

Mario  Garcia  Velez Habana 

Frederick  W.  Borton Habana 

Frederick  W.  Borton Habana 

Westinghouse  Elec.  Co Habana 

Roberto  E.  Ramires Habana 

Heraldo  de  Cuba Habana 

Luis       Casas Habuna 

E.  Sanchez  de  Fuentes Habana 

Fausto  Simon Habana 

Manuel  G.  Sslas Habana 

Rail  Parez  Falcon Habana 


400 

2K 

300 

2HS 

240 

20L 

360 

2WW 

260 

5EV 

320 

6KW 

220 

6KJ 

230 

6CX 

275 

6DW 

250 

6BY 

350 

6AZ 

270 

8BY 

280 

8FU 

150 

8DW 

Alvara  Daza Habana  200 

Julio  Power Habana  180 

Oscar  CoUado Habana  290 

Amadeo  Saenz Habana  210 

Lcopoldo  E.  Figueroa Colon  360 

Frank     H.     Jones Tuinucu  340 

Frank     H.       Hones Tuinucu  275 

Antonio  T.  Figueroa Cienfiegos  170 

Eduardo  Terry Cienfiegos  225 

Jose  Ganduie Cienfiegos  300 

Valentin  tllivarri Cienfiegos  200 

Alberto  Ravelo Stgo.  de  Cuba  250 

Andres  Vinnet Stgo.  de  Cuba  225 

Pedro  C.  Anduz Stgo.  de  Cuba  275 


European  Broadcasting  Stations 

British  Stations 


2LO  London 365 

51T  Birmingham %'* 

SWA  Cardiff ^|" 

6BM  Bournemouth J" 

2ZY  Manchester J'3 


5NO  Newcastle 400 

5SC  Glasgow 420 

2BD  Aberdeen : 492 

6SL  Sheffield  'relay  station) 303 


French  Stations 


Made  of  hicrh.  resistance  material  impreg- 
nated throughout  (not  coated  paper).  Un- 
affected by  climatic  conditions.  Will  not 
deteriorate.  Clamped  between  solid  knurled 
ferrules  assuring  rigid  construction  and 
firm  contact  at  all  times. 
At  your  dealer's,  otherwise  send  purchase 
price  and  you  -will  be  supplied  postpaid. 
Cliaa.  Frobmin  Co..  Inc..  2*0-248  W.  40th  St. 
Freshman    Bldg.,    N.   Y. 


MARVELOUS  NEW 
AUDIO  TRANSFORMER 

adds  a  musical qualityto  any  set  far 
beyond  anything  you  ever  heard 
before. 

KARAS .  HARMONIK 
Amplifies  low,  middle  and  high 
tones — allto  the  same  big  volume, 
thus  eliminating  distortion.  Brings 
outthevira  harmonics  and  over_ 
tones  of  music.  Price  $7.00.  Write 
Karas  Electric  Co.,   Depl.  58-93    4842  N.  Rockwell  St.,  Chicago 


IF  YOU  DON'T  See  what 
you  need  in  RADIO  AGE'S 
Advertising  Columns,  write  to 
the  Radio  Age  Buyers'  Ser- 
vice, 500  N.  Dearborn  St., 
Chicago,  and  all  buying  speci- 
fications will  be  furnished  you 
free  of  charge. 


5000 

RADIO  DEALERS 

buy  from 

HUM0N-R0JS 

123  W.  Madison  St.  Chicago 

Send  for  dealers  discount. 


MARSHALL  RadSeFcrel?ersnCy 

Embodying  a  marvelous  New     * 
Non-Oscillating  Principle 
Sold  Direct  on   Free  Trial  and  Easy  Terms 
Write  for  catalog  and  Special  Offer 

Marshall  Radio  Products,  Inc. 

Dept.  58-95  Marshall  Blvd. &  19th St.. Chicago 


*     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  May,  1925 

WITH 


The  Magazine  of  the  Hour  69 


URERS 


Thorola  "Doughnut  Coil" 

An  important  development  in  radio 
reception  is  announced  by  the  Reich- 
mann  Company  of  Chicago,  in  connection 
with  its  production  of  the  new  Thorola 
Low  Loss  Doughnut  Coil.  This  coil, 
subjected  to  the  most  rigid  tests,  will 
not  pick  up  or  absorb  any  signal  other 
than  that  brought  in  through  the  antenna 
system.  Its  magnetic  field  is  also  en- 
tirely con- 
fined,so  that 
there  is  no 
spray  to 
cause  inter- 
ference and 
intercoup- 
ling  between 
various 
parts  of  the 
set. 

The  new 
coil  is  of  the 
toroid  type, 
but  differs 
greatly  from 
all  other 
coils  of  this 
type  in  that 
it  shows  ex- 
tremely low  losses.  It  was  designed  by 
Frank  Reichmann,  designer  of  the  Thorola 
and  Thorophone  loud  speakers,  and 
marks  the  first  step  of  the  Reichmann 
Company  into  the  general  field  of  radio 
manufacture. 

Two  types  of  the  new  coil  will  be  put 
on  the  market;  one  to  be  used  as  a  coupler 
and  the  other  as  a  radio  frequency 
transformer.  They  will  improve  prac- 
tically every  kind  of  circuit  and  are  a 
distinct     advancement     in     radio. 


Baby  Grand  Reproducer  is 

Unique  Speaker 

The     Grigsby-Grunow-Hinds     Co.     of 

Chicago  announce  the  addition  of  a  new 

"Baby    Grand"    Model   to   their   line   of 

Majestic  Reproducer  loud  speakers.    The 

Baby  Grand  is  a  compact  loud  speaker 

that  retails  for  $9.00,  complete,  for  home 

use. 

The  tone 
quality  of  the 
Baby  Grand 
reproducer  is 
beyond  com- 
pare, accord- 
ing to  the 
makers,  who 
use  the  well- 
known  G-G-H 
Model  WG 
Constant 
Tension 
Diaphragm 
unit.  Volume 
is  also  said  to 
be  unusual  in 
this  unit.  The  horn  is  made  of  Du  Pont 
Pyralin,  which  is  said  to  eliminate 
harshness  or  metallic  sounds. 

Adjustable  volume  enables  the  user  to 


regulate  the  reproducer.  The  height  of 
the  Baby  Grand  is  13  inches  overall. 
The  diameter  of  the  bell  is  9  inches. 


R.  E.  Lacault  Joins- Phenix  as 
Chief  Engineer 

The  Phenix  Radio  Corporation  an- 
nounces that  Robert  E.  Lacault,  E.  E. 
A.  M.  I.  R.  E.,  designer  of  the  Ultradyne, 
has  become  Chief  Engineer  for  their, 
Corporation,  in  which  capacity  he  will 
further  his  inventive  genius  in  behalf  of 
the  Phenix  Ultra  products.  His  entire 
time  will  be  devoted  to  the  design,  dev- 
elopment and  perfection  of  certain  radio 
devices  that  are  destined  to  throw  new 
light  upon  radio  receiving  apparatus  in 
the  future. 

This  work,  like  the  famous  Ultradyne, 
originated  from  and  is  an  outgrowth  of 
his  four  years  as  Radio  Research  Engi- 
neer with  the  French  Signal  Corps  Labor- 
atories, where  he  put  to  good  use  his 
previous  intensive  electrical  studies,  de- 
signing various  types  of  radio  apparatus 
and  instruments,  working  on  the  first 
short-wave  radio  compass  equipment 
used  at  the  front  in  1915,  also  on  the  ear- 
liest wired  radio  and  aeroplane  radio 
equipment. 

Mr.  Lacault  was  one  of  the  first  ama- 
teurs in  France,  his  radio  experiments 
dating  back  as  far  as  1911.  In  the 
Research  Laboratory  of  the  French  Sig- 
nal Corps — Mr.  Lacault  worked  on  the 
TPS  Ground  Telegraphy  System,  a 
wired  radio  system  used  for  direct  and 
instant  communication  between  different 
radio  compass  stations,  by  means  of 
which  the  positions  of  enemy  stations 
were  found. 

In  recent  years,  Mr.  Lacault  worked 
on  radio  telephotography,  also  on  trans- 
mitting pictures  by  wire,  while  assisting 
Mr.  Bolin,  the  French  inventor.  This 
experience,  extending  over  a  period  of 
many  years,  gives  Mr.  Lacault  a  wonder- 
ful background  for  unusual  development 
in  his  new  connection  as  Chief  Engineer 
of  the  Phenix  Radio  Corporation. 


New  Sales  Manager  for  Crosley 
Corporation 

Walter  B.  Fulghum  has  been  appointed 
General  Sales  Manager  of  The  Crosley 
Radio  Corporation  and  began  his  duties 
March  first.  He  comes  to  the  organiza- 
tion with  a  broad  knowledge  of  mer- 
chandising and  sales  methods,  having 
been  associated  for  many  years  with  the 
Victor  Talking  Machine  Company  as 
head  of  their  Order  Department  in  Cam- 
den, N.  J. 

In  addition  to  the  experience  in  the 
manufacturing  side  of  the  business,  he 
has  had  experience  in  the  retail  business 
and  many  will  recall  his  record  of  boost- 
ing business  in  the  sale  of  phonographs 
in  the  months  of  July  and  August  and 
under  other  conditions.  His  broad  ex- 
perience will  enable  him  to  appreciate 
the  pioblems  of  both  distributor  and 
dealer. 


Radio  Concerns  Reorganize 
Expansion  and  stabilizing  of  the  radio 
industry  have  resulted  in  the  reorganiza- 
tion of  several  of  the  leading  manu- 
facturing concerns  and  the  issuing  of 
stocks.  These  stocks  have  made  sensa- 
tional records  in  the  New  York  and 
Chicago  Stock  Exchanges  recently,  due 
to  the  record  volume  of  sales  of  radio 
apparatus. 

The  latest  re- 
organization plan 
to  be  carried 
through  is  that 
following  the  for- 
mation of  the 
All  -American 
Radio  Corpora- 
tion, which  has 
taken  over  the 
business  of  the 
Rauland  Manu- 
facturing Com- 
pany, manufac- 
turers of  the 
largest  selling 
line  of  radio 
transformers  in 
the  world.      The 


E.  N.  Rauland 


new  company  is  headed  by  E.  N.  Rauland, 
one  of  the  pioneers  in  radio  manufacturing 
and  their  application  for  a  license  to 
manufacture  under  the  (radio  patents 
held  by  the  United  States  Navy  has 
been  approved  by  Secretary  Wilbur  of 
the   Navy   Department. 

Important  extensions  in  the  business 
of  the  company  are  planned  immediately. 
Especial  attention  will  be  given  to  the 
research  laboratory  work. 

Forty  thousand  shares  of  Ail-American 
stock  were  offered  to  the  public  at  $.26  a 
share.  It  was  oversubscribed  six  times 
and  before  being  listed  on.  the  Chicago 
Stock  Exchange,  it  was  bid  up  to  $36  a 
share.  The  statement  of  the  company 
shows  cash  assets  of  nearly  $550,000. 

Mr.  Rauland  started  the  business  as 
the  Ail-American  Electrical  Manufactur- 
ers. In  1922  it  was  incorporated  as  the 
Rauland  Manufacturing  Company.  Its 
chief  products  have  been  audio  and  radio 
transformers,  sockets,  fixed  couplings 
and  the  well-known  All-Amax  semi-fin- 
ished one  and  three  tube  sets. 


New  Steinite  Distributors 

The  radio  world  will  be  interested  in 
knowing  that  arrangements  have  now 
been  completed  which  enable  the  Steinite 
Laboratories,  Atchison,  Kans.,  to  an- 
nounce that  the  firm  of  E.  O.  Jackson  & 
Company,  504  South  State  Street, 
Chicago,  have  been  designated  as  ex- 
clusive distributors  of  their  products 
throughout  the  United  States  and 
Canada. 

The  items  manufactured  by  the 
Steinite  people,  and  now  made  famous 
by  extensive  advertising,  comprise  the 
Steinite  long  distance  crystal  set,  one, 
two  and  five  tube  receivers,  two  stage 
amplifier,  crystal,  crystal  detector,  and 
interference  eliminator. 


70 


RADIO  AGE  for   May,  1925 


The  Magazine  of  the  Hour 


CLASSIFIED  ADVERTISEMENTS 


Don't  overlook  the  value  of 
RADIO  AGE'S  classified  adver- 
tisements. Many  such  messages 
have  paved  the  way  to  independent 
incomes. 

The  classified  advertising  rates 
are  but  ten  cents  per  word  for  a 
single  insertion.  Liberal  discounts 
are     allowed     on     three,     six     and 


twelve  -  time  insertions,  of  five, 
fifteen  and  thirty  per  cent,  re- 
spectively. Unless  placed  through 
an  accredited  advertising  agency, 
cash  should  accompany  all  orders. 
Name  and  address  .must  be  in- 
cluded at  foregoing  rates  and  no 
advertisement  of  less  than  ten 
words  will  be  accepted. 


AGENTS  WANTED 


RADIO— Join  our  sales  organization  and  make  big 
money.  We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers. Widener  of  Kansas  City  makes  $150.00 
weekly.  You  can  do  as  well  or  better.  Write  today 
for  catalog,  and  discounts.  Name  your  county.  Wave- 
land  Radio  Company,  Div.  52,  1027  No.  State  St.,  Chi- 
cago,  111. 


MANUFACTURER'S    AGENT    calling 
trical  Jobbers,  Chicago  and  vicinity,  h 


la 


Radic 


on     Radio-Ele 


Chicago. 

AGENTS— WRITE  FOR  FREE  SAMPLES.  Sell  Madison 
■Better-Made"  Shirts  tor  large  manufacturer  direct  to 
wearer  No  capital  or  experience  required.  Many 
earn  $100  weekly  and  bonus.  MADISON  MFGRS..  501 
Broadway.   New  York. 


HELP  WANTED 


RADIO    SALESMEN 
you    and   you    need   u 


nd    SET    BUILDERS— We    need 
If    you    arc    reliable    and   well 

unity,   we   will   appoint   you   our 

representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago.  III. 


MANUFACTURING  FACILITIES 

AN  OLD  AND  WELL  ESTABLISHED  MANUFACTUR- 
ING COMPANY  IN  THE  M 1 DDLE  WEST  WITH  LARGE 
WELL  EQUIPPED  PLANTS  AND  UNUSUAL  FINAN- 
CIAL RESOURCES.  DESIRING  TO  ENTER  THE  RADIO 
FIELD  WILL  CONSIDER  THE  MANUFACTURE  AND 
SALE  OF  RADIO  SETS  OR  DEVICES  OF  OUTSTAND- 
ING AND  UNUSUAL  MERIT  ON  A  ROYALTY  BASIS. 
ADDRESS  BOX  1A.   RADIO  AGE. 

RADIO 

A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10. 
Postpaid,  less  phones  and  tube.  Complete  with 
phones  tube  and  battery.  $18.00.  J.  B.  RATHBUN. 
1067  Winona  St.,  Chicago,  111. 

Standard  soderless  radio  Jacks.  Binding  post  attach- 
ments. Double  circuit.  One  dollar  bill.  Postpaid. 
Clinton  Seward,  Jr.,   New  Paltz,   New   York,   N.   Y. 

Three  Cosmopolitan  Phusiformers.  each  $5.50.  book  of 
instructions   included.      F.   A.   Mall,   Triopli,    Iowa. 

FOR  SALE— 3  Pfanstiehl  tuning  units.  3  Cardwell  Con- 
densers 1  Bradleyometer.  2  Bradleystats.  All  goods 
New.     Earl  Price,  Lodi,  Wis. 


RADIO  CIRCUITS 


BLUEPRINTS— Make  your  own  set  from  proven 
original  and  up-to-the-minute  blueprints.  The  follow- 
ing are  merely  three  of  a  choice  of  almost  one  hundred 
different  types: 

HT-1-3— Five  tube  neutrodyne — 50c. 

FB-6 — Three-honeycomb  regenerative — 35c. 

D10-4— Diode  single  circuit— 25c. 

All  three  of  above,  for  $1.00. 

These  tested  blueprints  are  all  made  up  in  easily 
read  circuit  drawings.  MIDLAND  PRODUCTS  COM- 
PANY, 1413  Hood  Ave.,  Chicago,  111.  Ask  for  our  com- 
plete list,  No.  R-31. 


RADIO  DEALERS 

DEALERS — Write  for  our  illustrated  catalog  of  reliable 
Radio  Merchandise.  Rossiter-Manning  Corporation, 
Dept.  D,  1830  Wilson  Ave.,  Chicago,  III. 


STAMPS  AND  COINS 


158  Genuine  Foreign  Stamps.  Mexico  War  Issues. 
Venezuela.  Salvador  and  India  Service.  Guatemala. 
China,  etc.,  only  5c.  Finest  approval  sheets,  50  to 
60  per  cent.  Agents  Wanted.  Big  72-p.  Lists  Free. 
We  Buy  Stamps.  Established  20  Years.  Hussman 
Stamp  Co.,  Dept.  152,  St.  Louis.  Mo. 


WANTED 


WANTED — To  complete  my  set  RADIO  AGE  need 
August,  September,  October.  November.  1923.  issues, 
bound  or  unbound.  Advise  price.  Lloyd  C.  Henning, 
Hollbrook,  Arizona. 


WRITERS 


NEW  WRITERS  WANTED— Articles,  stories,  poems, 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No.  bunk.)  NOT  A  CORRE- 
SPONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
azines. Send  self  addressed  envelope  for  list  of  100 
subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Lob 
Angeles,  Calif. 


INVENTIONS 


WRITERS— Cash  in  on  your  knowledge  of  radio  by 
writing  for  Radio  Magazines  and  Newspaper  Supple- 
ments. Write  up  your  radio  experiences,  your  new 
hook-up,  your  knowledge  of  broadcasting  stations  and 
artists.  Experienced  authors  will  correct  and  improve 
your  manastripts— make  them  typically  professional 
work.  FREE  Criticism  and  Advisory  Service  until  your 
manuscript  is  sold!  ALL  Magazines  and  Papers  de- 
manding fiction  and  articles  dealing  with  radio.  Here 
is  YOUR  OPPORTUNITY  to  profit!  Send  for  FREE 
booklet,  "How  You  Can  Sell  Your  Manuscripts." 
Willis  Arnold  and  Associates,  210  East  Ohio  M .: 
Chicago,  III. 

NEW  IDEAS  WANTED— Well  known  Radio  Manufac- 
turer whose  products  are  nationally  advertised  and  sold 
everywhere  wants  new  Radio  device  to  sell.  Will  pay 
outright  or  royalty  for  idea  or  invention  which  is  really 
new  and  saleable.  Address:  Mr.  R.  F.  Devine,  Room 
1101.  116  West  32nd  St.,  New  York,  N.   Y. 


RADIO  TUBES 


SPECIAL  Mastertone  Radio  tubes  all  sizes  $1.85  post- 
paid.     Nangle  Co.    601  Washington  Boul.   Oak  Park,  III. 

AGENTS 

90c  an  hour  to  advertise  and  distribute  samples  to  con- 
sumer. Write  quick  for  territory  and  particulars. 
American  Products  Co.,  2130  American  Building,  Cin- 
cinnati, Ohio. 

Man  wanted  for  this  territory  to  sell  wonderful 
value  men's,  women's.  Children's  shoes  direct,  sav- 
ing consumer  over  40^7.  Experience  unnecessary. 
Samples  supplied.  Big  weekly  permanent  income. 
Write  today  Tanners  Mfg.  Co.,  1334C.  St..  Boston,  Mass. 


"R" 


B"  BATTERIES 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parts  and  plans — complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake.  Chicago. 


BATTERIES  FOR  SALE— Four  24-volt  "Main"  Storage 
"B"  Batteries,  never  used,  shipped  ancr  ready  to  wire 
for  $38.00.  First  order  gets  the  batteries.  Address 
Box  B,  Radio  Age,  500  N.  Dearborn  St.,  Chicago,   III. 


RADIO  OFFERS 


15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.  Every  item  guaranteed.  Tell  us  your  needs. 
IMPERIAL  RADIO  COMPANY,  Delaware,  Ohio. 


RADIO  SETS.      Our  prices  save  you  money.      Lists  free 
The  Radio  Shoppe,  Box  645,  East  Liverpool,  Ohio. 


JOIN  THE  RADIO  Parts  Exchange  Club.      Your  parts 

inspected    (Fee  25c),   and   exchanged  for   the   parts   you 

need.      What    have    you;    what    parts    do    you    reauire? 

Write  us  for  details. 

The  Radio  Parts  Exchange  Club,   112  So.  Homan  Ave. 

Chicago. 


RADIO  CIRCUITS 


SPECIAL  FOR  MAY 
The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne    fully 
illustrated,  and  RADIO  AGE,  for  $2.50.      Price  of  Book- 
let alone  is  50c.      Send  check,  currency  or  money  order 
to  RADIO  ACE,  500  N.  Dearborn  Street,  Chicago. 


VOCATIONS 


Make  Big  Money.  Safe  and  Lock  Expert.  Wayne 
Strong,  3800  Lan  Franco  St.,  Los  Angeles,  Calif. 

RADIO  SUPPLIES 

Ten  per  cent  discount  on  all  standard  radio  parts, 
from  condensers  to  transformers  to  tubes,  etc.  Send 
for  our  latest  price  list,  with  special  bargains  on  Static- 
eliminators,  portable  loud  speakers,  Radiotrons,  Ger- 
man silver  wire,  etc.  RADIOGRAPH  LABORATORIES. 
1234  Rosemont  Ave.,  Dept.  4,  Chicago,  111. 

Classified  ad.  copy  for  the  June 
RADIO  AGE  must  be  sent  in  by 
May  1,  1925. 


New  "Fada"  Announcement 

The  following  is  the  substance  of  a 
recent  letter  sent  to  the  distributors  of 
F.  A.  D.  Andrea,  Inc.,  relative  to  their 
policy  on   maintenance  of  prices. 

"Liquidation  is  being  put  into  effect 
by  a  number  of  radio  manufacturers. 
You  have  our  unqualified  assurance  that 
no  such  move  is  contemplated  by  Fada. 
We  have  previously  written  you  as  re- 
gards guarantee  on  prices  until  July  15, 
1925.  We  are  prompted  to  write  you 
again  giving  you  full  assurance  on  this 
matter  because  a  number  of  concerns 
have  had  certain  of  their  products 
advertised  recently  by  large  retail  out- 
lets and  at  an  enormous  price  reduction. 
Among  advertisements  of  this  nature 
which  have  recently  come  to  our  atten- 
tion, the  names  of  a  number  of  prominent 
radio  manufacturers,  who  in  our  opinion 
should  readily  recognize  the  need  for 
constructive  action  at  this  time  rather 
than  resort  to  dumping  ol  surplus, 
merchandise,     have  ,been    involved. 

"It  is  our  firm  intention  to  continue 
to  limit  our  salesj  exclusively  throughout 
authorized  jobbers  and  to  refrain  abso- 
lutely from  any  price  concessions  to 
large  retail  outlets.  We  believe  a  jobber 
who  has  invested  money  in  our  stock 
and  has  merchandised  our  product  along 
authorized  lines  is  entitled  to  proper 
protection.  We  believe  a  dealer  who 
has  purchased  our  merchandise  from  our 
jobbers  is  entitled  to  a  clear  path  in 
its  sale  to  the  user  and  should  not  be 
hampered  by  undue  competition  which 
must  result  from  price  reductions  through 
large  retail  outlets.  To  the  best  of  our 
ability  we  will  guard  against  any  such 
retail  outlets  offering  our  merchandise 
on  a  basis  which  will  create  any  such 
unfair  competition  to  our  regular  deal- 
ers." 


Radio  Show  for  St.  Louis 
in  October 

Plans  are  already  being  formulated  for 
the  holding  of  the  St.  Louis  Radio  Show 
at  the  Coliseum  in  St.  Louis,  Mo.,  during 
the  week  of  October  12,  1925.  The  show 
is  under  the  direction  of  the  St.  Louis 
Radio  Trades  Association,  of  which 
Colin  B.  Kennedy,  prominent  radio 
manufacturer,     is     president.  George 

Niekamp  is  to  be  director  of  the  show. 

The  week  of  October  12  has  been 
designated  as  "Radio  Week"  as  a  means 
of  stimulating  interest  in  the  exposition. 
Radio  stars  and  announcers  from  all 
over  the  country  will  attend  the  show,  and 
broadcasting  will  be  conducted  direct 
from  the  Coliseum,  where  special  studios 
will  be  equipped.  Already  scores  of 
exhibitors  have  either  signed  up  for. 
booths  or  announced  their  intention  of 
doing  so. 

According  to  plans  now  under  way, 
this  will  be  the  "National  Radio  Show 
of  the  Great  Southwest"  for  1925. 


f  I  >  readers  wish  to  show  their 
I  r^  approval  of  the  stand  taken 
"*"*■  by  RADIO  AGE  against  the 
Radio  Corporation  of  America,  they 
can  do  it  in  the  most  practical  way 
by  sending  $2.50  for  a  year's  sub- 
scription to  our  magazine,  or  if  they 
are  already  subscribers,  urge  a  friend 
to  subscribe.  We  believe  the  fans 
are  with  us.  Address  Radio  Age, 
Inc.,  500  N.  Dearborn  St.,  Chicago. 


RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


71 


With  the  Manufacturers 


Care  in  Connecting  Condensers 
Important 

Fixed  condensers,  when  used  in  radio 
receivers,  are  not  always  given  the  proper 
care  which  they  need  for  the  important 
w'ork  they  have  to  perform. 

The  placing  of  hot  soldering  irons 
against  a  condenser  will  in  most  cases 
do  one  of  three  things;  change  the 
capacity;  short  the  circuit  or  open  the 
circuit. 

Another  thing  that  does  not  give  the 
condenser  an  even  chance  is  the  using  of 
soft  iron  bolts,  which  should  be  avoided 
for  the  reason  that  they  will  sometimes 
draw  up  too  tightly  and  change  the 
capacity.  The  use  of  soft  iron  builds 
up  a  temporary  magnet  circuit. 

As  a  means  of  getting  the  utmost  out  of 
a  circuit  and  to  utilize  all  signal  strength 
instead  of  weakening  it,  the  Ridge 
Manufacturing  Co.,  3818  N.  Ridgeway 
Ave.,  Chicago,  has  perfected  the  "Handy 
Condenser  Clip"  to  eliminate  the  fore- 
going faults  and  to  make  the  radio  re- 
ceiver just  that  much  better. 

H.  H.  Eby  Mfg.  Co.'s  Patent 

H.  H.  Eby  Mfg.  Co.  of  Philadelphia, 
the  makers  of  Eby  Binding  Posts, 
make   the    following    announcement: 

"The  United  States  Government  has 
issued  patent  No.  1529244,  dated  March 
10,  1925,  to  Hugh  H.  Eby,  president 
of  the  H.  H.  Eby  Mfg.  Co.  This  patent 
fully  covers  the  binding  posts  which 
we  have  manufactured  and  sold  for  the 
last  five  years.  Our  attorneys  have 
advised  us  that  if  we  intend  to  protect 
our  customers  and  ourselves  against 
infringing  manufacturers,  the  legal  tech- 
nicalities of  the  case  require  an  announce- 
ment of  the  issuance  of  the  patent  and 
the  fact  that  we  are  prepared  to  defend 
our  rights. 

"We  have  gone  a  step  farther  and 
clearly  marked  the  base  -of  every  post 
frhich  leaves  our  factory  with  our  name 
and  patent  number  in  order  to  make 
identification    easy. 

"We  have  felt  very  much  gratified 
by  the  many  instances  which  we  have 
seen  of  the  fairmindedness  of  the  radio 
trade  as  a  whole.  After  all,  Americans 
hate  a  fraud.  A  large  number  of  our 
jobbers  and  numerous  manufacturers 
who  are  using  our  posts  on  their  sets 
have  sent  us  samples  of  various  posts 
which  have  been  offered  to  them  by 
unscrupulous  competitors.  They  have 
recognized  the  fact  that  we  were  the 
originators  of  this  type  of  post  and  have 
assured  us  that  they  would  continue  to 
buy  from  us,  no  matter  how  many  other 
companies  tried  to  steal  our  ideas  of 
design   and   construction." 

Radio  Loud  Speaker  Horn  Good  for 
Portables 
The  American  Hard  Rubber  Company 
has  come  to  the  aid  of  the  portable  radio 
fan  with  a  Radion  horn  and  phone  cap 
to  use  on  a  loud  speaker  and  headphone 
or  headphone  unit.  The  horn  is  small 
enough  to  be  placed  in  a  radio  cabinet, 
measuring  but  10  inches  high.  It  has 
excellent  tone  quality  and  amplifying 
possibilities.  The  horn  and  the  cap  are 
highly  polished,  and  will  make  a  minia- 
ture loud  speaker  out  of  a  headset  by 
simply  screwing  the  cap  over  the  unit 
of  tlie  headphone.  The  price  of  the  horn 
is  $2.50. 


Meco  Introduces  New 
Radio  Sets 

Simplified  tuning  obtained  by  two 
dial  controls  with  only  one  dial  to  log 
are  the  principal  features  of  the  radio 
receivers  announced  by  the  Metropolitan 
Electric  Company  of  Des  Moines,  manu- 
facturers of  the  well  known  Meco  Tubes. 

The  radio  sets  will  be  marketed  under 
the  brand  name  of  "Meco"  and  will  all 
be  of  five  tubes. 

Three  different  models  are  being  manu- 
factured. All  of  the  sets  are  similar  in 
operation,  circuit  and  size.  One  model 
will  retail  at  approximately  $60.00. 
Another  cabinet  model  will  retail  at 
approximately  $100.  And  the  period 
design  console  model  will  be  priced  at 
about  $250.00. 

The  Meco  radio  sets  operate  on  radio 
frequency  action,  having  two  stages  of 
radio  frequency  amplification,  two  stages 
of  audio  amplification  and  detector. 

When  ordered,  Meco  sets  will  be 
supplied  with  tubes  matched  to  the  set 
at  the  factory.  This  effects  better  re- 
ception and  eliminates  a  great  deal  of 
trouble  for  purchasers  and  dealers  alike. 

The  extreme  selectivity  of  the  Meco 
sets  is  attributed  to  the  simplified  tuning 
produced  by  two  dial  controls. 


Mohawk  Corporation  to  Expand 
The  Mohawk  Electric  Corporation  is 
about  to  open  a  new  branch  office  at  1400 
Broadway,  New  York  City.  Appoint- 
ment of  H.  G.  Cisin  as  manager  of  this 
branch  has  also  been  announced.  Mr. 
Cisin  has  been  associated  with  the  Mo- 
hawk organization  in  the  capacity  of 
sales  and  advertising  manager  since  the 
company  started  manufacturing  the  Mo- 
hawk single  dial  5-tube  receiver,  and  his 
promotion  to  manager  of  this  important 
New  York  post  will  not  surprise  his 
many  friends  in  the  radio  industry.  Be- 
sides being  well-known  in  the  trade,  Mr. 
Cisin  is  also  known  to  radio  fans  as  the 
author  of  several  technical  works  on 
radio  and  electricity.  Besides  the  new 
metropolitan  office  being  established  in 
New  York,  the  Mohawk  Electric  Cor- 
poration also  maintains  district  sales 
branches  in  Boston,  St.  Louis,  Los  An- 
geles, San  Francisco,  Portland,  Denver, 
Minneapolis,  Detroit  and  Cedar  Rapids. 
The  main  offices  are  located  in  Chicago. 


The  Liberty  Radio  Chain 
Stores 

David  Kanofsky,  President  of  Liberty 
Radio  Chain  Stores,  at  a  dinner  given 
by  him  to  his  Metropolitan  managers 
and  salesmen,  expressed  great  optimism 
for  the  future  of  Liberty.  In  his  re- 
marks Mr.  Kanofsky  hinted  that  an  im- 
portant consolidation  was  under  consid- 
eration and  called  attention  to  the  fact 
that  the  company  plans  to  open  addi- 
tional stores  and  that  it  plans  to  open 
retail  radio  stores  throughout  the  country. 

Mr.  Kanofsky  expressed  great  satis- 
faction in  the  results  thus  far  accom- 
plished and  stated  that  he  looked  forward 
to  the  new  6-Tube  "Clearfield,"  which 
will  be  marketed  through  the  Liberty 
organization,  to  prove  an  outstanding 
success,  stating  that  already  the  radio 
buyer  had  evidenced  a  great  interest  in 
this  new  set,  which  is  enclosed  in  plate 
glass;  hence  its  name,   Clearfield. 

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72  RADIO  AGE  for  May,  1925 


The  Magazine  of  the  Hour 


All  You  Want  to  Know 
About  Hookups ! 


Above  is  a  circuit  diagram  of  a  hookup  published  in  the  RADIO  AGE  A  N  N  UAL  for  1925,  and  which  has 
taken  the  radio  fans  by  storm!  Although  it  is  but  a  three-tube  affair,  it  consistently  "pulled  in"  California 
stations  on  the  loudspeaker  while  located  less  than  a  mile  from  two  powerful  Chicago  broadcasting  stations' 
Hookups  such  as  these  make  the  ANN  UAL  for  1925  a  necessity  in  your  store  of  radio  knowledge. 

Let  the   Radio  Age  Annual  for   ig2$   Teach    You  Radio! 

IF  YOU  are  going  to  build  yourself  a  new  radio  this  Spring  and 
Summer,  or  if  you  want  a  new  set  for  your  Summer  vacation, 
the  RADIO  AGE  ANNUAL  for  1925  will  fulfill  your  every  technical 
need.  Scores  of  tried  and  true  hookups,  tested  in  every  detail  in  the 
RADIO  AGE  Laboratory,  are  contained  in  this  wonder  hookup 
book  of  120-pages,  with  its  complete  beginners'  section,  32-page 
blueprint  section  for  beginner  and  expert,  and  its  wealth  of  material 
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How  to  read  and  understand  hookups. 
How  to  understand  radio  phenomena 
Building  your  first  simple  set. 
How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set. 
How  to  amplify  any  kind  of  set. 
Making  a  reflex  set. 
Building  your  first  Reinartz  set. 
The  renowned  Baby  Heterodyne  No.  1. 
Adding  audio  and  radio  stages  to  the  Baby  Het. 
How  to  make  a  battery  charger. 
How  to  make  a  loud  speaker. 

RADIO    AGE    ANNUAL    BLUEPRINT    SECTION    with    such 
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How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super-heterodyne  for  the  super  experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

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5-Volt 

Tubes 

C-300and  UV-200 
areinterchange- 

able 
C-301A.  DV-2  and 
UV-201A  are  In- 
terchangeable 

« 

UV-200 

1 

69  WHR 

22 

67  WHR 

16 

2 

UV-201A 

Vz 

67  WHR 

33 

2 

1  UV-200 
1  UV-201A 

I'/i 

611  WHR 

22 

69  WHR 

17 

3 

UV-201A 

3/S 

69  WHR 

29 

67  WHR 

22 

3 

1  UV-200 

2  UV-201A 

V/z 

611  RHR 

21 

69  WHR 

14 

1 

UV-20IA 

1 

69  WHR 

22 

67  WHR 

16 

4 

1  UV-200 
3  UV-201A 

Wt 

613  RHR 

22 

611  WHR 

15 

5 

UV-201A 

l'/4 

611  WHR 

22 

69  WHR 

17 

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5 

1  UV-200 
4  UV-201A 

2 

613  RHR 

19 

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611  WHR 

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6 

UV-201A 

l'/z 

611  RHR 

21 

69  WHR 

14 

Sm 

8 

UV-201A 

2 

69  KPR 

21 

67  KPR 

15 

For  sets  using  cur- 
rent at  a  rate  higher 
than  2  amperes. 

VA 

69  KR1. 

22 

67  KPR 

13 

2V2 

69  KRL 

19 

^^§1^ 

69  KPR 

16 

..„— „M,i.\4W 

InP 

How  to  fit 

storage  batteries  to  your  set 


It  pays  to  buy  wisely — to  select 
batteries  that  bring  out  the  best  in 
your  set  and  are  of  the  right  ca- 
pacity  to  give  fine  reception  at 
recharging  intervals  best  suited  to 
your  convenience. 

The  new  Prest'OLite  Radio 
Chart  tells  you  how  to  select  such 
batteries.  The  part  of  the  master 
chart  shown  here  covers  "A"  Bat' 
teries  for  5'volt  tube  sets.  Use 
either  of  the  two  sizes  recommended 
for  your  set,  depending  on  the  days 
of  service  you  wish  between  recharg' 
ings  (based  on  the  average  use  of 
your  set  of  three  hours  a  day).  You 
will  find  the  larger  capacity  battery 
more  desirable  unless  facilities  are 
provided  for  frequent  and  easy  re' 


charging.  For  "B"  Batteries,  and 
"A"  Batteries  for  peanut  tubes,  see 
the  complete  chart  at  your  dealer's. 

Special  structure  plates,  high 
porosity  separators  and  scientific  in 
ternal  construction  make  Prest'O 
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them  at  your  dealer's — or  write  for 
"How  to  fit  a  storage  battery  to 
your  set — and  how  to  charge  it." 


Write  today  for 
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Whether  you  have  a 
one-tube  set  or  most 
advanced  multi-tube 
outfit,  you'll  find  a  fund 
of  interesting  informa- 
tion  in  our  booklet, 
"How  to  fit  a  storage 
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This  booklet  gives 
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technically  accurate  rec- 
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both  "A"  and  "B"  stor- 
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type  of  set. 

In  addition,  there  is 
much  vitally  important 
data  on  battery  care  and 
upkeep — information 
that  any  radio  fan  will 
find  of  real  value  in  keep- 
ing his  set  at  its  maxi- 
mum efficiency.  Write 
for  your  copy  right  now. 


# 


THE  PREST-O-LITE  CO.,  Inc.,  INDIANAPOLIS,  IND. 

New  York  San  Francisco 

In  Canada:    Prest-O-Lite  Company  of  Canada,   Ltd.,  Toronto,  Ont. 


*     Tested  and  Approved   by  RADIO   AGE     * 


Htm 


The  recognized  outstanding  achievement  in  radio  is  the 
Crosley  Trirdyn.  An  overburdening  amount  of  evidence 
proves  that  it  is  excelled  by  none  and  superior  to  most 
receivers  costing  many  times  more.  It  is  a  three  tube 
radio  combining  one  stage  of  tuned  radio  frequency,  re- 
generative detector  and  reflex  amplification.  This 
combination  enables  three  tubes  to  do  the  work  of  five 
or  six.  Brings  in  every  large  station  in  the  country  on 
the  loud  speaker.      Is  very  selective,   easy  to  tune   and 


economical  to  operate-  The  straight  front  Trirdyn 
Regular,  formerly  $65;  now  $50.  Tne  Trirdyn  Special 
in  large  cabinet  to  house  dry  cell  batteries  formerly  $75; 
now  £60.  To  these  have  been  added  the  new  Trirdyn 
Regular  with  sloping  panel  at  $55  and  the  new  Trirdyn 
Special  in  a  beautiful  cabinet  with  sloping  panel  at  $65. 
Demand  a  Crosley  Trirdyn  at  any  good  dealer.  All 
Crosley  radios  are  licensed  under  Armstrong  Regener- 
ative U.  S.  Patent  1,113,149.     Write  for  catalog. 


Prices  quoted  without  accessories.  West  of  Rockies  add  10% 

THE  CROSLEY  RADIO  CORPORATION 

POWEL  CROSLEY,  JR.,  President 

563  Sassafras  Street        -  Cincinnati,  Ohio 

Crosley  owns  and  operates  Broadcasting  Station  WLW 


mmsmh 


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Only  the  Best  is  "Good  Enough" — 

The  difference  between  a  radio  set  that  "works" — even  one 
that  "works  well" — and  Zenith,  is  the  difference  between 
always  longing  for  "something  better"  and  the  supreme 
pleasure  of  owning  the  best  that  money  can  buy. 
True,  Zenith  costs  a  bit  more,  but  evening  after  evening, 
month  after  month,  year  in  and  year  out,  you  will  thank 
your  lucky  stars  that  you  paid  that  trifling  difference  and 
made  sure  of  the  best  in  radio  results.  .  *' 

— Tuning,  for  instance,  so  simple  that  with  two  dials  only 
you  can  bring  in  every  important  station  on  the  air  clearly 
and  in  ample  volume.  Powerful  locals  may  be  on  full  blast, 
yet  you  tune  straight  through  at  will,  get  distant  stations. 
— More  stations  in  a  given  length  of  time  than  with 
any  other  make.  Direct  comparisons  invited. 
The  proof  that  Zenith  is  the  set  you  want  is  yours  for  the  asking. 
Only  selected  dealers  who  are  prepared  to  give  service  handle  , 
Zenith.  Ask  your  nearest  Zenith  dealer  for  a  demonstration. 


-CoshMm^utfloesMm 


ZENITH  RADIO  CORPORATION 

332  South  Michigan  Avenue,  Chicago 
ITH  —  the  exclusive  choice  of  MacMillan  for  his  North  Polar  Expedition 


fer 


The  complete  Zenith  line  ranges  in 
price  from  $100  to  $475. 
With  either  Zenith  3R  or  Zenith  4R,  sat- 
isfactory reception  over  distances  of 
2,000  to  3,000  miles  is  readily  accom- 
plished, using  any  ordinary  loud 
speaker.  Models  3R  and  4R  licensed  un- 
der Armstrong  U.  S.  Pat.  No.  1,113,149. 
They  are  NON-RADIATING. 

Zenith  4R  -  -  $100 
Zenith  3R  -  -  $175 

The  new  Super-Zenith  is  a  six-tube  set 
with  a  new,  unique,  and  really  different 
patented  circuit,  controlled  exclusively 
by  the  Zenith  Radio  Corporation.  It  is 
NOT  regenerative. 

SUPER-ZENITH  VII  — Six  tubes-2 
stages  tuned  frequency  amplification  — 
detector  and  3  stages  audio  frequency 
amplification.  Installed  in  a  beautifully 
finished  cabinet  of  solid  mahogany  — 
44%  inches  long,  16%  inches  wide,  10% 
inches  high.  Compartments  at  either 
end  for  dry  batteries.  Price  (ex-  (fc'J  A.f\ 
elusive  of  tubes  and  batteries)  ^P^T'V' 
SUPER-ZENITH  VIII—  Same  as  VII  ex- 
cept— console  type.  Price  (ex-  Q'Jf+C} 
elusive  of  tubes  and  batteries)  H'^'U^ 
SUPER-ZENITH  IX —Console  model 
th  additional  compartments  contain- 
ing built-in  Zenith  loud  speaker  and  gen- 
erous storage  battery  space.  Price  (ex- 
clusive of  tubes  and  bat-  (tlCC 

teries) tyJDD 

SUPER-ZENITH  X— Contains  built-in, 
patented,  Super-Zenith  Duo-Loud  Speak- 
ers (harmonically  synchronized  twin 
speakers  and  horns),  designed  to  repro- 
duce both  high  and  low  pitch  tones 
otherwise  impossible  with  single-unit 
speakers.  Price  (exclusive  of  <fc<4,'7£ 
tubes  and  batteries) *PT*  ■  -^ 

All  Prices  F.  O.  B.  Factory. 


ZENITH  RADIO  CORPORATION 

Dept.  C-6. 
332  S.  Michigan  Ave.,  Chicago,  III. 

Gentlemen:  Please  send  me  illustrated  liter- 
ature about  Zenith  radio. 

Name 


#     Tested  and  Approved  by  RADIO  AGE     # 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour  1 


EarirfO  to  '200  a  Week 

in  RADIO 


You  can  !  Hundreds  of  ambitious  men  are  al- 
ready earning  thousands  of  dollars  in  this  won- 
derful new  industry — you,  too,  can  get  your 
share.  Mail  coupon  below  for  Free  Book  which 
describes  fully  the  amazing  money- making 
opportunities  in  Radio  and  tells  you  how  YOU 
can  earn  from   $5,000   to   over  $10,000  a  year. 


THE  astounding  growth  of  Radio 
has  created  thousands  of  big 
money  opportunities.  Millions  of 
dollars  were  spent  d  uring  the  pas  t  year 
on  Radio,  and  thousands  of  young 
men  are  needed  right  now  to  meet 
the  ever-increasing  demand  of  work. 
Men  are  needed  to  build,  sell  and 
install  Radio  sets — to  design,  test, 
repair — as  Radio  engineers  and  ex- 
ecutives— as  operators  at  land  sta- 
tions and  on  ships  traveling  the 
world  over — as  operators  at  the 
hundreds  of  broadcasting  stations. 
And  these  are  just  a  few  of  the 
wonderful  opportunities. 

Easy  to  Learn  Radio  at 
Home  in  Spare  Time 

No  matter  if  you  know  nothing 
about  Radio  now,  you  can  quickly 
become  a  Radio  expert,  by  our 
marvelous  new  method  of  practical 
instruction — instruction  which  in- 
cludes all  thematerialforbuildingthe 
latest  up-to-date  Radio  apparatus. 

Scores  of  young  men  who  have 
taken  our  course  are  already  earn- 


PAY  INCREASES  OVER 
J100  A  MONTH 

I  am  averaging  anywhere  from  S75 
to  S150  a  month  more  than  I  was 
making  before  enrolling  with  you.  I 
would  not  consider  S10.000  too  much 
for  the  course. 

(Signed)   A.  N.  10NG. 

Greenburg.   Pa. 


DOUBLES  SALARY 

I  can  very  easily  make  double  the 
amount  of  money  now  than  before  I 
enrolled  with  you.  Your  course  has 
benefited  me  approximately  S3, 000 
over  and  above  what  I  would  have 
earned  had  I  not  taken  it. 

T.  WINDER. 
Grand  Junction,  Colo. 


FROM  $15  TO  $80  A  WEEK 

Before  I  enrolled  with  you  I  was 
making  S15  a  week  on  a  farm.  Now 
I  earn  from  S2.080  to  34,420  a  year, 
and  the  work  is  a  hundred  times  easier 
than  before.     Since  graduating  a  little 


_  ,  I  ha 
10.  and  I  believe  the  cour 
orth  at  least  S100.000  to  I 
(Signed!  GEO.  A.  ADAMS, 


will 


Tamaqua.  Pa. 


ing  from  $75  to  $200  a  week.  Merle 
Wetzel  of  Chicago  Heights,  111., 
advanced  from  lineman  to  Radio 
Engineer,  increasing  his  salary  100% 
even  while  taking  our  course!  Em- 
mett  Welch,  right  after  finishing 
his  training,  started  earning  $300 
a  month  and  expenses.  Another 
graduate  is  now  an  operator  of  a 
broadcasting  station — PWX  of  Ha- 
vana, Cuba — and  earns  $250  a 
month.  Still  another  graduate, 
only  16  years  old,  is  averaging 
$70  a  week  in  a  Radio  store. 

Wonderful  Opportunities 

Hardly  a  week  goes  by  without 
our  receiving  urgent  calls  for  our 
graduates.  "We  need  the  services 
of  a  competent  Radio  Engineer." 
"We  want  men  with  executive 
ability  in  addition  to  Radio  knowl- 
edge to  become  our  local  managers." 
"We  require  the  services  of  several 
resident  demonstrators" — these  are 
just  a  few  small  indications  of  the 
great  variety  of  opportunities  open 
to  our  graduates. 

Take  advantage  of  our  practical 
training  and  the  unusual  conditions 
in  Radio  to  step  into  a  big  paying 
position  in  this  wonderful  new  field. 
Radio  offers  you  more  money  than 
you  probably  ever  dreamed  possible 
— fascinating,  easy  work — a  chance 
to  travel  and  see  the  world  if  you 
care  to,  or  to  take  any  one  of  the 
many  Radio  positions  all  around 
you  at  home.  And  Radio  offers 
you  a  glorious  future! 

The  National  Radio  Institute  is 
one  of  America's  Pioneer  Radio 
Schools — established  in  1914.  Our 
course  is  an  absolutely  complete  one 
which  qualifies  for  a  government 
first-class  commercial  license.  It 
gets  you  bigger  paying  jobs  in  Radio. 
'     Tested  and  Approved  by  RADIO  AGE     * 


Send  for 
FREE  RADIO  BOOK 

Learn  more  about  this  tremendous  new  field  and 
its  remarkable  opportunities.  Learn  how  you  can 
quickly  become  a  radio  expert  and  make  big  money 
in   Radio. 

We  have  just  prepared  a  new  32-page  booklet 
which  gives  a  thorough  outline  of  the  field  of  Radio 
■ — and  describes  our  amazing,  practical  training  in 
detail.  This  Free  Book,  "Rich  Rewards  in  Radio," 
will  be  sent  to  you  without  the  slightest  obligation. 
Mail  coupon  for  it  now! 

For  a  short  time  we  are  offering  a  reduced  rate  to 
those  who  enroll  at  once.  Act  promptly  and  save 
money. 


National 

Radio 

Institute 


Dept.  53  HB 
Washington, 
D.  C. 


NATIONAL  RADIO  INSTITUTE, 
Dept.  53HB,  Washington,  D.  C. 

Please  send  me  without  the  slightest  obligation 
your  Free  Book.  "Rich  Rewards  in  Radio."  and  full 
details  of  your  special  Free  Employment  Service. 
Please  write  plainly. 


Name.. 


Address.. 
City _. 


RADIO  AGE  for  June,   1925 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITH   WHICH  IS  COMBINED   RADIO  TOPICS 


Volume  4 


June,  1925 


Number  6 


CONTENTS 

Cover  Design  by  Fred  I.  Good 

Page 

Radio  Editorials 4 

Overcoming  Static  Disturbances-- ._. 7 

By  Roscoe  Bundy 

The  Joys  of  Outdoor  Radio 11 

By  Armstrong  Perry 

A  Portable  Super-Heterodyne ..13 

By  H.  Frank  Hopkins 

Experimental  Circuits  for  the  Double  Grid  Tubs. ...16 

By  C.  R.  Bluzat 

A  Scientific  Five-Tube  Receiver... 17 

By  M.  B.  Sleeper 

The  Roberts  Receiver.. ■_ 19 

By  Frank  D.  Pearne 

An  Ideal  Set  in  Practical  Form ...21 

By  McMurdo  Silver 

How  to  Attain  Proper  Soldering 23 

Page  of  Technical  Pictures 
RADIO  AGE  "What  the  Broadcasters  Are  Doing" 

— Studio-Land  Feature  Section 24-33 

RADIO  AGE  Institute  Monthly  Tests. 34 

RADIO  AGE  BLUEPRINT  SECTION 35 

A  Three-Tube  Portable  Set 
By  John  B.  Rathbun 

Pickups  and  Hookups  by  Our  Readers 43 

Corrected  List  of  Broadcasting  Stations... 64 

With  the  Radio  Manufacturers... 69,  72 


Radio  Age  is  published  monthly  by  RADIO  AGE,   Inc. 
Member:      Audit  Bureau  of  Circulations. 


Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500    N.  Dearborn    Street,    Chicago,    111. 
Publication   Office,    Mount    Morris,    111. 


Frederick  A.  Smith,  Editor 
Russell  H.  Hopkins,  Associate  Editor 
Frank  D.  Pearne,  Technical  Editor 
M.  B.  Smith,  Business  Manager 


Advertising  Director 
HARRY  A.  ACKERBURG 

500  N.  Dearborn  St.,  Chicago,  III. 


Eastern  Representative 
DAVIDSON    &   HEVEY,    17  West  42nd  St. 


New  York  City 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 

preceding  date  of  issue 

Vol.  4,  No.  6.     Issued  monthly.     Subscription  price  $2.50  a  year.      June.  1925. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris,  Illinois,  under  the 

Act  of  March  3,  1879. 

Ccwriaht.  19S5.  by  RADIO  AGE,  Inc. 


A  Chat  With 
the  Editor 


ANY  editor  who  attempts  to 
follow  the  winding  trail  pur- 
sued by  the  Radio  Corpora- 
tion of  America  cuts  out  a  man's 
job  for  himself.  Month  after 
month  and  year  after  year  the 
court  records  add  voluminously  to 
the  serious  charges  brought  by  in- 
dependent radio  manufacturers 
against  the  $33,000,000  concern. 
This  in  addition  to  the  charges 
made  by  the  United  States  govern- 
ment through  the  Federal  Trade 
Commission,  which  accuses  the 
Radio  Corporation  of  America  of 
being  a  party  to  a  conspiracy  in 
restrain  of  trade. 

The  latest  accusation  against  the 
R.  C.  A.  is  made  by  the  DeForest 
Radio  Company,  which  has  ob- 
tained an  injunction  in  the  New 
Jersey  courts  restraining  the  Radio 
Corporation  of  America  from  at- 
tempting to  steal  business  from  the 
DeForest  Corporation  and  filch 
scientific  secrets  from  the  De- 
Forest  Corporation.  It  is  alleged 
in  the  bill  that  the  Radio  Corpora- 
tion of  America,  to  quote  the  New 
York  Times,  "introduced  spies  into 
its  (DeForest  Company's)  offices 
to  steal  business  and  technical 
secrets  and  had  seduced  DeForest 
employes  into  acts  of  treachery." 
The  Radio  Corporation  was  or- 
dered by  the  court  to  turn  over  all 
records  obtained  by  the  alleged  sys- 
tem of  espionage  and  warned  the 
Radio  Corporation  not  to  destroy 
any  such  records,  pending  hearing 
of  arguments  to  make  the  in- 
junction permanent. 

And  this  is  free  and  glorious 
America! 

It  is  enough  to  make  a  good 
American  blush  with  shame  that 
such  a  rotten  mess  as  this  should 
reach  the  point  where  it  breaks 
into  news-print.  We  have  observed 
that  various  big  chiefs  of  big  radio 
interests  have  acquired  a  mania 
for  rough-riding  the  industry.  They 
are  riding  to  their  own  destruction 
and  riding  fast. 

Editor  of  RADIO  AGE 


RADIO  AGE  for  1925 


The  Magazine  of  the  Hour 


ilifpjy 


fWW 


|^*«il!AOE>m»au-"" 


.. 


Evereadys  have 
long-lasting  power 

THE  long-lasting  power  of  Evereadys 
more  than  justifies  their  price.  It  is 
false  economy  to  buy  batteries  that  may 
be  cheaper  in  first  cost,  but  which  are 
much  shorter  lived.  Considering  price 
and  size,  Evereadys  are  the  most 
economical  batteries  there  are,  and  in 
addition  they  are  most  satisfactory. 
Buy  Eveready  "B"  Batteries.  To  light 
the  filaments  of  all  radio  dry  cell  tubes, 
use  the  famous  Eveready  Columbia 
Ignitor. 

Manufactured  and  guaranteed  by 

NATIONAL   CARBON    COMPANY,   Inc. 
New  York  San  Francisco 

Canadian  National  Carbon  Co.,  Limited.  Toronto,  Ontario 

EVEREADY 

Radio  Batteries 

'-they  last  longer 


0^r 


No.  766 
22'A-volt 

Large 

Horizontal 

Price 

$2.00 


life. 


=;^ 


$3.75 


: 


*     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


RWIO  CORPORATION  of  America  sent  one  of 
its  patent  attorneys  all  the  way  from  New  York 
-  to  Iowa  City,  Iowa,  to  take  the  deposition  of  a 
woman  who  formerly  was  a  newsdealer  in  that  city.  The 
testimony  was  wanted  by  the  Radio  Corporation  for  the 
purpose  of  convincing  the  Patent  Office  in  Washington 
that  this  magazine  was  injuring  the  business  of  "Wire- 
less Age"  by  continuing  to  use  the  title  "Radio  Age". 
The  "Wireless  Age"  is  owned  and  controlled  by  the 
Radio  Corporation  of  America. 

This  magazine  was  represented  at  the  Iowa  City 
proceedings,  May  4.  We  are  going  to  tell  what  took 
place  down  there  in  Iowa  so  that  those  who  have  paid 
good  money  for  stock  in  the  Radio  Corporation  of 
America  may  know  how  the  Broadway  radio  patriots 
spend  their  time  and  money.  We  think  radio  manu- 
facturers, dealers  and  the  radio  public  generally  will 
be  interested,  also. 

Mrs.  C.  Merton  Sulser,  of  Iowa  City,  in  June  of  last 
year  was  a  wholesale  news  agent  in  Iowa  City.  She 
received  a  telegram  from  "Wireless  Age"  asking  her  to 
undertake  the  sale  of  that  magazine.  Mrs.  Sulser  did 
not  then,  and  apparently  does  not  now,  know  much 
about  radio  publications.  In  spite  of  the  fact  that  the 
telegram  from  the  "Wireless  Age"  carried  a  New  York 
date  line,  Mrs.  Sulser  on  June  24  sent  a  telegram  to 
"Radio  Age"  in  Chicago  ordering  twenty  copies  of  this 
magazine  monthly.  This  magazine  promptly  replied 
that  it  already  had  a  wholesale  distributor  in  Iowa 
City  and  therefore,  could  not  serve  her.  On  the  same 
day  Mrs.  Sulser  received  this  letter  from  "Radio  Age" 
she  received  a  letter  from  "Wireless  Age"  supplement- 
ing the  telegram  which  had  solicited  her  services  as  a 
wholesale  agent.  Mrs.  Sulser  waited  until  July  18  of 
that  year  and  then  wrote  a  letter  to  "Wireless  Age" 
+elling  them  she  had  made  a  mistake  and  had  sent  a 
telegram  to  "Radio  Age"  instead  of  to  "Wireless  Age." 
Oh  joy!  Oh  Paine's  Fireworks!  Whoopla!  Here  was 
the  evidence  at  last.  "Radio  Age"  had  turned  down  an 
order  from  a  woman  who  thought  she  was  ordering 
something  else  but  was  not  quite  sure  which  or  what. 
Therefore  "Radio  Age"  was  injuring  the  business  of 
"Wireless  Age."  Off  to  Iowa  City  with  lawyers  and 
depositions  and  everything.  Let  the  welkin  ring  and 
the  streets  grow  dark  with  mystery  and  let  the  Patent 
Office  in  Washington  hold  its  breath.  Let  the  cashiers 
dig  down  for  traveling  expenses  and  busy  men  leave 
their  work. 

Yes,  the  president  of  Radio  Age,  Inc.  was  present  to 
hear  the  deposition  taken.  It  may  be  that  some  other 
woman  in  Portland,  Ore.,  Portland,  Me.,  Amarillo, 
Tex.,  Birmingham,  Ala.,  Pasadena,  Cal.,  Skunkvillle, 
Miss.,  or  Timbuctoo,  down  near  King  Tut's  tomb,  may 
have  made  a  mistake  in  ordering  magazines  and  picked 
as  her  first  choice  an  independent  publication  instead 
of  one  owned  and  controlled  by  the  Radio  Corporation 
of  America,  which  admits  it  entered  the  radio  game 
from  patriotic  motives. 

It  may  be  that  "Radio  Age"  may  be  dragged  hither 


and  thither  and  yon.    But  not  all  the  harassing  tactics 
of  the  Broadway  people  can  change  the  facts. 

"Radio  Age"  rightfully  uses  its  title.  It  was  the  first 
to  use  that  title  in  interstate  commerce.  It  began  the 
use  of  the  title  in  March,  1922. 

"Wireless  Age"  wants  to  grab  our  name  because  it  is 
the  best  name  in  the  radio  publication  field.  It  has 
already  changed  its  own  title  to  read  "Wireless  Age, 
the  Radio  Magazine."  The  Radio  Corporation  of 
America  should  have  changed  its  name  from  "Wireless 
Age"  to  "Radio  Age"  before  "Radio  Age"  came  into 
the  field.    Then  it  would  have  some  rights. 

We  suggest  to  readers  that  they  turn  to  the  contents 
page  and  read  what  the  DeForest  Radio  Company  says 
of  the  Radio  Corporation's  espionage  system.  It  makes 
one  wonder  what  stockholders  in  the  Radio  Corporation 
think  of  it  all.  Radio  Corporation  perhaps  does  not 
relish  the  fact  that  this  magazine  hits  from  the  shoulder 
when  it  talks  about  trust  practices.  We  haA'e  only  one 
answer  to  that.  Radio  fans  and  dealers  and  manu- 
facturers are  with  us,  thousands  strong. 

Having  left  Iowa  City,  Iowa,  with  our  depositions, 
where  do  we  go  from  here? 

THE  New  York  Evening  Graphic  of  April  22  pub- 
lished on  the  first  page  an  interview  in  which  the 
following  statement  was  attributed  to  Gen.  J.  G.  Har- 
bord,  president  of  the  Radio  Corporation  of  America: 

I  understand  some  of  the  smaller  manufacturers 
have  had  a  slump  in  their  business.  This,  I  think, 
in  the  long  run.  will  be  beneficial  to  the  radio  business 
as  it  will  tend  to  eliminate  the  weaker  manufacturers 
and  make  the   industry  more  solidified. 

Radio  Age  wrote  to  Gen.  Harbord  and  asked  him 
if  he  had  been  correctly  quoted.  He  replied  that  the 
article  was  a  "mis-statement." 

We  are  glad  to  present  this  correction  for  Gen.  Har- 
bord because  we  are  aware  of  the  fact  that  the  radio 
industry  as  a  whole  was  astonished  by  the  publication 
of  such  an  interview.  The  trade  was  surprised  that  the 
head  of  a  corporation  that  is  under  federal  charges  as  a 
trust  conspirator  should  so  frankly  discuss  the  removal 
of  the  "smaller"  manufacturers  from  the  field  of 
activity. 

We  have  asked  the  editor  of  the  New  York  Evening 
Graphic  to  let  us  know  as  to  how  the  paragraph  quoted 
came  to  find  the  light  in  his  newspaper.  As  we  go  to 
press  we  have  had  no  reply  from  the  editor  of  the 
Graphic.  We  hope  he  will  confirm  Gen.  Harbord's 
statement  and  once  and  for  all  clear  the  Radio  Corpora- 
tion of  America  of  the  suspicion  that  it  wishes  to  "solidi- 
fy" the  radio  industry  by  the  "elimination"  of  the 
smaller  manufacturers.  Such  elimination  would  leave 
Radio  Corporation  the  king  of  all  it  surveys.  We 
feel  sure  that  in  these  days  of  free  competition  and  all 
our  carefully  built  bulwarks  against  restraint  of  trade 
and  unfair  competition,  the  Radio  Corporation  would 
not  wish  to  live  if  its  survival  depended  upon  the 
death  of  the  independents.     NO  SIR-REE    . 


Look  out  for  "The  Radio  Spies!"  Read  About 
Them  in  July  "Radio  Age" 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour  $ 


Vi&ilan  c  e 


Leader shi 


Every  All- American 
transformer  has  stamped 
upon  it  a  serial  number 
which  identifies  the  rec- 
ord of  its  individual  test 
at  the  factory.  The  man- 
ufacturerstands  behind  it 
absolutely  provided  this 
serial  number  is  not  ef- 
faced. Lookf or  the  number , 
and  for  the  famous  red 
guarantee  tag  with  the 
inspector's  punch  marks. 


Of  what  importance  is  it  to  you,  as  a  user  of  radio 
transformers,  to  know  that  any  particular  brand, 
such  as  All- American,  has  held  continuously  for  a 
number  of  years  the  position  of  proven  leadership 
in  quantity  of  sales? 

Simply  this :  that  such  an  achievement  is  the  best 
possible  proof  of  continued  satisfaction  given  to  other 
users  of  All- Americans.  The  average  purchaser  of 


a  transformer  chooses,  above  all,  an  instrument 
which  has  been  recommended  to  him  by  a  person 
whose  judgment  he  respects. 

Only  by  the  most  thorough  accuracy  and  care  in 
manufacturing,  and  unusual  care  in  testing,  is  it 
possible  for  All- American  to  maintain,  year  after 
year,  this  position  of  commanding  leadership.  Let 
it  be  your  protection! 


* 


A  new  edition  of  the  Radio  Key  Book,  just  oft"  the  press,  illustrates  an  eight-tube 
set  which  is  the  sensation  of  the  year.    Send  10  cents  for  it  now,  coin  or  stamps. 


ALL-AMERICAN  RADIO  CORPORATION,  2680  Coyne  St.,  Chicago,  111. 

£.  N.  Rauland,  President 

All-American 

Largest  Selling  Transformers  in  the  World 


*     Tested  and  Approved,  by  RADIO   AGE     * 


6  RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Mr.  Manufacturer 

Would  you  write  100  letters 

to  100  people 

to  reach  just  two  men? 

Then,  before  you  invest  your  advertising  dollars — THINK! 


An  analysis  shows  that  publications  of  general  circulation, 
newspapers  and  magazines,  devote  less  than  2%  of  their 
reading  columns  to  Radio — proving  that  in  the  opinion  of 
their  own  Editors  less  than  2%  of  their  readers  are  inter- 
ested in  Radio.  In  fact,  many  general  publications  carry  no 
Radio  editorial  matter.  Therefore — 98%  of  your  investment 
is  lost! 


This  Association 
is  comprised  of 
the  leading  Ra- 
dio Magazines. 


On  the  contrary,  the  Radio  magazine  offers  100%  Radio 
editorial — attracts  100%  potential  buyers. 

Spend  your  advertising  appropriation  in  Radio  Magazines. 
Be  sure  of  the  greatest  possible  return  on  your  advertising 
dollar. 

Radio  Magazine  Publishers'  Association,  Inc. 

RADIO  AGE  is  a  member  of  the  Radio  Magazine  Publishers  Association,  Inc. 


r 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


3BI IB! 


L 


M.  B.  Smif/i 

Business  Manager 


Jfie  Marine  ftho  Hour 


/l  Monthly     Publication 

Devoted  to  Practical 

Radio 


E]E]E==3EIE==:ir:ir=^=1r1r=^=":11 IBI IBI IBE 


1BI  'BE 


3131=' 


Frederick  A.  Smith 

Editor 


irni  imi  ini  int= 


SEES 


Make  This  a  Radio  Summer  by 


Reducing  STATIC  Disturbances 


LS  the  Summer  season  advances,  the 
l\  "static  belt"  creeps  farther  and 
•*-  •*-  farther  north  from  the  equatorial 
zone,  and  by  the  time  that  this  issue  of 
RADIO  AGE  is  off  the  press  it  is  certain 
that  the  great  majority  of  our  readers 
will  have  been  given  a  taste  of  imported 
tropical  conditions,  and  will  be  in  the 
market  for  any  ideas  or  devices  which 
will  enable  them  to  tune  out  that  roaring, 
crackling  and  crashing  that  mars  their 
reception  and  subdues  their  DX  ambi- 
tions. We  can  be  grateful  that  the 
northerner  is  treated  to  only  a  few  months 
of  this  sort  of  trouble  instead  of  having 
static  at  his  door  all  the  year  around  as 
they  do  in  the  tropics. 

Manj'  anti-static  devices  have,  been 
suggested  from  time  to  time  which  are 
either  wholly  or  partly  successful  in 
reducing  the  intensity  of  the  static 
crashes  so  that  the  signals  can  be  dis- 
tinguished above  the  general  uproar. 
Some  are  simple  and  others  are  rather 
complicated  in  theory,  but  all  of  them 
are  well  worth  a  tryout  until  one  par- 
ticular arrangement  is  found  that  most 
perfectly  meets  your  local  conditions. 
Any  static  eliminator  which  so  reduces 
the  interference  to  a  point  where  the 
crackling  is  not  audible  during  the 
program,  and  can  only  be  heard  faintly 
during  the  intermissions,  can  be  con- 
sidered highly  successful  from  the  broad- 
cast listener's  point  of  view,  and  with 
careful  attention  to  the  following  matter, 
the  amateur  can  generally  rig  up  some 
sort  of  contraption  which  will  greatly 
improve  the  clarity  of  the  signals  and 
somewhat  extend  the  range  of  his  re- 
ceiver. 

As  noise  from  static  and  radio  signals 
are  both  the  result  cf  electrical  disturb- 
ances, and  since  both  strike  the  aerial  at 
the  same  time,  it  is  rather  a  difficult 
matter  to  "unscramble"  them  so  that  the 
charges  induced  by  the  electromagnetic 
radio  waves  are  retained,  and  the  im- 
pulses due  to  atmospheric  electric  charges 
are  grounded  and  rejected.  In  fact, 
this  separation  is  partly  made  possible 
by  the  fact  that  some  radio  signals 
are  of  much  higher  frequency  (or  shorter 
wavelength),  than  the  static  impulses, 
and    hence    the    two    can    sometimes   be 


By  ROSCOE  BUNDY 

How  to  Make  a  Good 
"Anti-Static'  Device 


separated  by  some  form  of  tuning  or 
filter  system.  By  suitable  arrangement 
of  choke  coils,  which  will  stop  the  radio 
waves  but  which  will  allow  low  frequency 
and  D.  C.  static  to  escape  to  earth,  it  is 
possible  to  greatly  reduce  the  rattlings 
and  other  disagreeable  noises. 

Atmospheric  Electricity 

STATIC  may  be  due  to  two  causes:  (1) 
To  strong  electrical  charges  deposited 
on  the  aerial  by  the  highly  charged  air 
particles  of  the  atmosphere,  and  (2) 
True  electromagnetic  waves  sent  out  by 
lightning  discharges  or  by  emanations 
from  the  Aurora  Borealis.  That  the 
atmosphere  is  a  highly  charged  envelope 
may  prove  a  novel  explanation  to  many 
of  our  readers,  but  it  has  been  proved 
repeatedly    by    meteorologists    that    the 


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upper  strata  of  the  earth's  atmosphere 
may  be  charged  to  hundreds  of  millions 
of  volts  above  the  potential  of  the  earth 
itself.  These  charges  may  not  be  directly 
evident  to  our  senses,  but  they  can  be 
measured  by  the  proper  instruments 
carried  in  sounding  balloons  or  airplanes. 
Variations  in  these  charges  are  painfully 
evident  to  the  listener-in  during  the 
Summer  season. 

By  some  means,  not  universally  agreed 
upon  by  scientists,  each  molecule  or 
minute  particle  of  air  carries  an  electrical 
charge.  This  charge  may  have  been 
produced  originally  by  the  friction  of  the 
air  molecule  in  rubbing  over  solid  objects 
or  over  other  molecules  surrounding  it. 
Again  it  may  have  been  the  result  of  the 
action  of  sunlight  or  of  evaporation. 
Whatever  the  cause,  it  can  be  easily 
demonstrated  that  the  air  is  a  strongly 
charged  mass  of  varying  intensity  and 
polarity,  sometimes  positive  and  some- 
times negative,  but  always  with  the 
charge  in  evidence. 

At  high  altitudes  the  potential  or  in- 
tensity of  the  charge  is  greater  than  at 
points  near  the  earth's  surface,  and  at 
cloud  levels  the  concentration  during 
thunderstorms  may  reach  hundreds  of 
millions  of  volts.  In  fair  weather,  the 
charge  may  have  a  much  lower  potential, 
but  in  general  we  can  estimate  at  least 
50,000  volts  near  the  normal  cloud  levels. 
One  investigator  estimates  the  increase 
to  amount  to  approximately  100  volts  per 
foot  of  height  under  average  conditions 
in  northern  latitudes,  but  this  is  only 
the  roughest  sort  of  a  guess.  Actually, 
the  potentials  change  day  by  day  at  any 
locality  and  also  through  a  still  greater 
range   with   the   seasons. 

The  relative  polarities  of  the  earth 
and  atmosphere  may  change  completely 
within  a  few  hours,  and  again,  the 
polarity  may  not  be  the  same  at  all 
altitudes,  alternating  strata  of  positive 
and  negative  charges  being  found  at 
different  heights.  As  with  all  natural 
phenomena  it  is  an  irregular  and  complex 
proposition. 

Fig.  1  illustrates  what  is  known  as  a 
"uniform  potential  gradient;"  that  is,  it 
shows  the  even  and  gradual  increase  in 
voltage  or  potential  as  we  increase  our 


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77;e  Magazine  of  the  Hour 

height  above  the  earth  at  the  stations 
(1-2-3-4-5-6-7),  we  assuming  that  a  con- 
stant polarity  is  maintained  at  all  heights. 
At  a  very  small  elevation  (1),  the  differ- 
ence in  potential  between  the  air  particle 
(1)  and  the  earth  is  one  volt.  At  (2)  we 
have  risen  about  one  foot  and  at  this 
point  the  potential  has  increased  to  100 
volts.  At  (3)  we  have  moved  up  by  20 
feet  and  the  potential  difference  is  now 
1,000  volts.  This  increase  goes  on  step 
by  step  until  we  reach  the  elevation  (7) 
where  a  potential  of  10,000,000  volts  is 
indicated. 

Puncturing  a  Foot  of  Air 

LJXDER  the  conditions  shown  in  Fig.  1 
'  no  discharge  can  take  place  and  no 
damage  can  be  done  to  objects  resting  on 
the  earth  for  the  reason  that  the 
resistance  of  a  one  foot  layer  of  air  is 
far  too  great  for  100  volts  to  puncture. 
For  example,  if  station  (2)  exceeds  the 
potential  of  station  (1)  by  100  volts,  then 
no  flow  of  current  can  take  place  through 
the  one  foot  strata  of  air  separating  these 
stations.  To  puncture  an  air  strata  one 
foot  thick  would  require  hundreds  of 
thousands  of  volts.  While  the  voltage 
is  accumulative  with  increasing  alti- 
tudes, the  air  resistance  is  also  accumula- 
tive, thus  preventing  any  discharge  from 
taking  place  as  long  as  the  charge  is 
distributed  through  the  mass  of  the  air. 
Discharge  can  only  take  place  when  the 
charges  are  all  concentrated  over  a  small 
area,  as  in  the  case  of  a  thunder  and 
lightning  storm. 

So  long  as  the  charges  remain  at  rest, 
as  shown,  they  can  have  no  audible 
effort  on  an  aerial  hung  at  any  altitude. 
To  produce  sounds  in  the  headset  re- 
quires that  the  intensity  or  polarity  be 
varied  so  that  the  diaphragms  of  the 
headset  are  moved  back  and  forth. 
With  an  (A-A)  aerial  hung  high  above  the 
earth,  and  grounded  through  the  radio 
receiver  (R),  a  continuous  unvarying 
depletion  of  potential  will  take  place 
which  has  no  effect  whatever  upon  the 
diaphragm  of  the  phones.  Thus,  at 
the  aerial  (A-A)  a  potential  of  approxi- 
mately 100,000  volts  will  be  maintained 
which  will  flow  through  the  grounded 
receiver  (R)  to  earth.  The  flow  in 
amperes  will  be  exceedingly  low  as  the 
air  particles  give  up  their  charges  to  the 
aerial  very  slowly.  The  flow  of  current 
increases  with  the  area  of  contact  made 
between  the  aerial  and  the  air,  and  hence 
the  flow  of  atmospheric  current  is  greater 
with  large  diameters  and  long  wires 
than  with  small  diameter  short  aerials. 
When  the  sun  beats  down  upon  the 
earth,  the  layer  of  air  next  to  the  earth 
is  heated  to  a  higher  temperature  than 
the  layers  far  above  it.  The  heating 
continues  until  the  buoyancy  of  the 
heated  air  strata  becomes  so  great  that 
it  finally  breaks  through  the  envelope 
of  cold  air  and  starts  a  vertical  circula- 
tion as  in  Fig.  2.  This  is  a  complete 
circuit,  the  "upcomer"  arising  at  (a-a), 
and  the  "down-comer"  descending  at 
(b-b).  This  is  illustrative  of  the  "air 
pockets"  so  commonly  mentioned  by 
aviators. 

When  this  vertical  circulation  or  "re- 
mous"  is  established,  our  potentials  and 
polarities  are  all  upset.     Negative  earth 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


charges  are  carried  up  to  the  aerial  at 
one  end  by  the  stream  (a-a),  and  positive 
high  potential  air  charges  are  brought  into 
contact  with  the  aerial  (A-A)  by  the  down- 
coming  stream  {b-b).  The  total  result 
is  that  the  aerial  is  subjected  to  rapidly 
varying  potentials  and  polarities,  and 
rattling  sounds  are  now  heard  in  the 
phones  of  the  receiver  (R).  A  high  posi- 
tive charge  on  the  aerial  is  rapidly  suc- 
ceeded by  a  low  potential  negative 
charge,  and  again  by  another  positive 
charge  of  different  intensity;  hence  there 
is  a  rapidly  fluctuating  series  of  charges 
on  the  aerial  which  result  in  the  rattle 
and  crashing  known  as  "static."  This 
is  one  of  the  many  causes  of  static  which 
may  be  called  "local  static." 

The  hotter  the  sun,  the  more  rapid  the 
air  circulation,  and  the  greater  will  be 
the  crashing  and  crackling.  When  the 
sun  is  overcast  by  clouds,  the  circulation 
is  reduced  or  entirely  stopped,  hence  the 
trouble  with  local  static  is  greatest  with 
a  bright,  hot  sun  and  is  least  in  cool,  cloudy 
weather.  As  any  aviator  will  tell  you, 
"bumpy"  air  is  the  worst  on  hot,  still 
days  with  no  horizontal  wind,  and  prac- 
tically does  not  exist  in  cold  weather  or 
with  strong  horizontal  winds  which  mow 
down  the,  vertical  currents. 

Thunderstorm  Mechanism 

\  THUNDERSTORM  is  another 
J-*-  source  of  snapping  and  cracking  in 
the  receivers,  for  the  flashes  of  lightning 
act  like  the  spark  of  the  old  time  spark 
transmitter  used  in  sending  code.  Fur- 
ther, the  thunderstorm  sets  up  violent, 
vertical  air  currents,  highly  charged, 
which  affect  the  aerial  according  to  the 
method  already  described.  A  high  local 
temperature,  a  high  degree  of  moisture 
in  the  air,  and  an  opportunity  to  develop 
vertical  air  currents  give  birth  to  a  thun- 
derstorm. Such  storms  cannot  start 
with  strong  horizontal  winds,  although 
they  may  afterward  cause  high  winds 
indirectly  after  they  are  thoroughly 
established. 

Fig.  3  is  a  diagrammatic  representation 
of  a  thunderstorm  during  its  develop- 
ment. The  whole  affair  starts  in  with  the 
establishment  of  a  vertical  air  current 
on  a  hot,  sultry  day  with  the  air  contain- 
ing sufficient  moisture  to  condense 
rapidly  at  a  slightly  reduced  tempera- 
ture. The  moist  air  starts  to  ascend 
along  {a-a),  and  in  the  course  of  time 
builds  up  to  an  altitude  (T)  where  the 
temperature  is  low  enough  to  cause 
condensation  and  to  form  visible  clouds 
of  water  vapor.  At  this  height,  the  air 
is  cooled  and  descends  along  the  line 
(6-6)  until  it  strikes  the  earth  and  is 
again  heated  sufficiently  to  re-ascend  along 
(a-a).  This  continues  until  a  consider- 
able area  of  clouds .  is  formed  at  the 
altitude  (TG),  and  as  each  minute 
particle  of  water  carries  an  electrical 
charge  with  it,  the  cloud  bank  finally 
becomes  a  highly  concentrated,  charged 
mass  formed  by  the  accumulation :  of 
the  individual  charges.  The  ever-in- 
creasing velocity  of  the  vertical  current 
throws  the  vapor  higher  and  higher 
until  some  of  it  is  thrown  up  into  an 
altitude  where  the  temperature  is  low 
enough  to  cause  freezing.  The  water 
vapor   now  becomes  an   intensely  white 


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10  RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


FREEZIING    /^LT 


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mass  of  tiny  ice  particles  at  (TH),  the 
brilliantly  white  peaked  mass  commonly 
called  the  "thunderhead." 

In  passing  from  an  invisible  vapor  to  a 
visible  cloud  composed  of  small  water  and 
ice  droplets,  the  intensity  of  the  vapor 
charge  is  increased  by  condensation. 
As  each  drop  of  visible  moisture  or  drop- 
let contains  thousands  upon  thousands 
of  the  vapor  particles,  the  droplet 
therefore  also  contains  the  concentrated 
charges  of  all  of  the  vapor  particles  and 
the  potential  of  the  water  drop  is  there- 
fore enormously  greater  than  that  of  the 
vapor.  This  goes  on  and  on  until  a 
terriffic,  concentrated  potential  is  es- 
tablished at  (T)  and  (TH),  which  is 
powerful  enough  to  break  down  and  to 
discharge  to  earth  through  the  resistance 
of  several  miles  of  air.  This  discharge 
is  "lightning,"  and  occurs  in  its  familiar 
form  as  at  (Z).  The  total  charges  of  the 
moisture  gathered  from  many  square 
miles  of  earth  surface  are  concentrated 
into  the  small  area  (M-M). 

With  the  storm  advancing  to  the  left 
as  shown  by  the  arrow,  a  person  at  (/) 
will  feel  no  wind,  but  when  the  clouds 
have  moved  so  that  we  are  standing  at 
(d)  we  will  feel  the  first  blast  of  ice  cold 
air  brought  down  by  the  downcomer 
(b-b).  The  current  is  now  more  inclined 
to  the  horizontal  so  that  we  feel  the  wind 
strongly,  and  on  glancing  up  we  will  see 
the  familiar  rolling,  tumbling  "scud"  of 
clouds  (S)  caught  between  the  up  and 
down  moving  columns  of  air.  The  cur- 
. rents,  become  more  and  more  horizontal 
as  the  storm  advances  and  the  earth 
velocities  become  higher  and  higher  as  at 
(g">  and  (h).  Lightning  flashes  issue  at 
rapid  intervals  at  (Z),  extending  from  the 
clouds  to  earth. 

In  the  course  of  time,  the  charge  gradu- 
ally extendstothecloudsatthe  rear  (right) 


for  horizontal  equalizing  flashes  of  light- 
ning (X)  run  back  from  the  thunderhead 
to  the  clouds  of  lower  potential  as  at 
(C2).  We  will  now  have  a  considerable 
area  of  charged  cloud  (C1-C2),  and  verti- 
cal strokes  of  lightning  will  take  place  at 
any  point  in  this  zone.  Continued 
flashes  (X)  from  cloud  to  cloud  soon 
bring  the  potential  of  (C2)  up  to  that  of 
(Cl),  and  finally  one  flash  (X)  will  over- 
charge (C2)  so  that  the  heavy  earth 
flash  (Z2)  will  take  place.  The  latter 
gives  the  sharp,  single,  gun-like  report 
that  indicates  danger.  Both  (X)  or  (Z) 
are  reverbrating,  rumbling  and  rattling 
discharges. 

Strange  to  say,  the  heavy  flashes  (Z) 
or  (Z2)  have  little  effect  on  the  radio 
receiver  unless  they  are  very  close  to  it, 
for  the  reason  that  the  magnetic  flux  set 


up  by  vertical  flashes  lies  in  a  horizontal 
plane  and  therefore  does  not  cut  through 
the  aerial.  The  real  source  of  noise  is 
in  the  horizontal  transfer  discharges 
such  as  (X),  for  these  are  parallel  to  the 
aerial  and  therefore  induce  charges  in  it. 
Lightning  discharges  are  oscillatory  and 
have  much  the  effect  of  a  spark  trans- 
mitter producing  damped  waves.  The 
clouds  and  the  earth  form  the  two  plates 
of  the  transmitting  condenser  and  the 
path  of  the  stroke  is  the  inductance. 
This  makes  it  difficult  to  tune  out  such 
discharges. 

Static  Crashes  and  Tuning 

WHEN  a  radio  receiving  circuit  is 
tuned  for  the  reception  of  a  given 
wavelength,  it  will  oscillate  when  the 
aerial  is  cut  by  a  wave  of  that  frequency. 
Unfortunately,  the  radio  receiving  circuit 
will  also  oscillate  at  the  given  wavelength 
when  any  other  disturbance  strikes  the 
aerial,  such  as  the  contact  charges  of  the 
air  or  the  oscillation'  waves  of  the  light- 
ning discharge.  This  is  independent  of 
the  frequency  of  the  disturbing  system. 

For  example,  let  us  say  that  we  have 
our  set  tuned  to  a  wavelength  of  360 
meters.  As  soon  as  the  360  meter  wave 
comes  from  the  transmitter,  the  receiver 
will  oscillate  in  step  with  the  incoming 
wave  as  usual.  Now  let  us  say  that  a 
strong  atmospheric  contact  charge  comes 
into  contact  with  the  aerial  with  the 
receiver  tuned  as  before,  the  charge  itself 
having  no  frequency.  If  the  charge  is 
heavy  enough  it  will  set  the  receiver 
circuit  to  oscillating  at  360  meters  as 
before,  making  it  impossible  to  tune  out 
heavy  static  charges  by  the  usual  means. 
To  make  a  receiver  static-free.it  must  be 
arranged  so  that  it  will  not  oscillate  when 
"shocked"  by  any  external  force  except 
by  the  desired  radio  wave.      (To  -page  52) 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour  1 1 


The  Joys  of 
W8&& Outdoor  Radio 


By 

ARMSTRONG 

PERRY 


The  set  laid  out  and  mounted  on  a  board  at  the 
door  of  your  tent.  A  string  thrown  over  the  limb  of 
a  tree  holds  the  aerial,  which  runs  from  the  set  to  the 
limb  of  the  tree.  Extreme  simplicity  is  the  keynote 
of  this  Summer-time  outfit. 


ROUGHING  it  nowadays  consists 
principally  of  seeing  how  many  of 
our  city  comforts  and  conven- 
iences we  can  lug  to  some  locality  where, 
because  the  trees  have  not  all  been  cut 
nor  complete  sewage  systems,  water 
front  developments  and  paving  plans 
completed,  city  folks  can  huddle  with 
enough  change  of  scene  to  make  a  topic 
of  conversation  for  the  ensuing  winter. 
The  touring  car  of  the  Summer  traveler 
carries  more  equipment  and  supplies 
than  many  a  prairie  schooner  that  was 
both  home  and  transportation  for  a  large 
family  for  several  months  in  the  pioneer 
days.  Adventurous  spirits  read  eagerly 
how  Enos  A.  Mills  spent  days  at  a  time 
on  the  summit  of  the  Continental  Divide 
in  Winter  with  only  a  handful  of  raisins 
for  food  and  no  shelter  at  all  except 
possibly  his  elk-skin  sleeping  bag,  but 
Enos  had  to  build  log  cabins  with  steam 
heat,  hot  and  cold  water  and  bath  tubs 
in  order  to  tempt  said  adventurous 
spirits  to  go  out  and  have  a  look  at  the 
mountains  that  he  loved. 

And  we  simply  must  have  radio! 

Radio  Easy  to  Handle 

TT  IS  easy  enough  to  carry  a  radio 
-*-  outfit  on  any  outing,  long  or  short. 
It    is    risky    to    carry    the    home    outfit, 


even  if  its  bulk  and  weight  are  not  too 
great,  for  cabinets  and  insulation  de- 
signed for  indoor  use  are  likely  to  absorb 
enough  moisture  in  the  open  on  a  rainy 
day  to  ruin  the  set.  A  better  method  is 
to  improvise  a  rough  and  ready  outfit 
that  can  be  used  without  anxiety,  because 
even  if  it  should  be  damaged,  the  loss 
would  not  be  great. 

Reduced  to  the  minimum,  a  tube  set 
consists  of  a  single-wire  aerial,  one  in- 
ductance coil,  one  variable  condenser, 
one  grid  leak  and  condenser,  one  tube, 
one  rheostat,  one  "A"  battery,  one  "B" 
battery,  a  pair  of  phones  and  a  ground 
connection.  Amplifier  units  and  a  loud 
speaker  can  be  added  if  desired. 

It  is  just  as  much  fun  to  figure  out 
how  these  devices  can  be  mounted  in 
the  smallest  space  as  it  is  to  get  out  the 
old  fishing  rod,  shellac  the  w-oodwork 
and  oil  the  joints,  but  it  is  not  necessary 
to  mount  them  at  all.  Unmounted, 
they  can  be  tucked  away  in  the  corners 
of  a  haverasck  or  traveling  bag  in  which, 
ensemble,  they  would  present  a  problem 
comparable  to  that  of  finding  room  for 
the  things  she  forgot  in  the  wife's  trunk. 

The  aerial  wire  can  be  of  small  size 
that  will  coil  easily.  A  quarter-pound 
or  half-pound  spool  of  No.  20  or  22  is 
all   right   and   it   can   be   respooled  in   a 


minute  after  it  is  taken  down.  Insu- 
lators are  necessary,  but  a  length  of 
twine  soaked  in  oil  will  serve  the  purpose. 
Where  there  are  trees  the  aerial  can  be 
elevated  to  a  better  height  than  the  usual 
home  aerial.  It  is  not  necessary  to  climb 
the  trees  unless  a  too  inquisitive  bull 
moose  appears  during  the  process  of 
erection.  A  ball  of  chalk  line  and  a 
plumb  bob,  or  any  piece  of  twine  with 
a  weight  on  the  end,  can  be  whirled  like 
a  sling  to  throw  the  weight  over  a  high 
branch,  after,  which  the  wire  can  be 
hauled  aloft  at  your  leisure.  Trees 
themselves  have  been  used  as  aerials. 
■There  was  a  spasm  of  it  in  the  early  days 
of  broadcasting.  So  there  need  be  no 
undue  anxiety  over  accidental  contacts 
between  wire  and  branches  unless  re- 
sults at  the  receiver  are  poor. 

Assortment  of  Coils 

A50-turn  honeycomb  coil,  mounted, 
costs  only  about  one  dollar,  and  its 
weight  adds  little  to  a  pack.  To  insure 
a  tuning  range  to  suit  all  tastes,  it  is 
well  to  have  a  size  or  two  on  each  side 
of  this — say  35  turns  and  75  turns.  A 
single-coil  mount  is  a  convenience  but 
is  not  indispensible. 

The   plate  type  of  variable  condenser 
is    easily   injured,    but   the    danger   can 


12 


RADIO  AGE /or  June,  1925 


The  Magazine  of  the  Hour 


A  simple  set  to  take  along  on  your  vacation  trip  and  assemble  at  your  leisure.     Notice 

that  only  parts  absolutely  neccessary  are  used  and  yet  this  outfit  will  produce  satisfactory 

results  at  minimum  expense. 


be  eliminated  by  purchasing  one  in 
knock-down  form  and  assembling  it  as 
wanted.  The  assembly  occupies  even 
the  novice  only  a  few  minutes  and  the 
second  or  third  time  it  is  put  together 
the  operation  becomes  almost  mechani- 
cal. Forty-three  plates  will  make  the 
largest  condenser  commonly  used  in 
radio  receiving.  If  you  have  that  many, 
you  can  make  condensers  of  any  desired 
size  merely  by  assembling  more  or  less 
plates.  Book-type  condensers,  ready- 
made,  occupy  less  room  and  weigh  less. 
There  are  also  some;  very  small  con- 
densers, operated  by  dials,  that  have 
capacities  similar  to  the  11 -plate,  23- 
plate,    43-plate   and   other   sizes. 

Grid  leaks  and  grid  condensers  are  so 
cheap  and  small  as  to  present  no  prob- 
lems. It  is  only  necessary  to  make  sure 
that  you  have  the  correct  resistances 
and  capacities  for  the  tube  to  be  used. 
Low-voltage  tubes  that  can  be  lighted 
by  drjr  cells  are  usually  preferred  in 
portable  outfits,  but  if  the  automobile 
with  its  storage  battery  is  sure  to  be 
where  it  is  wanted  at  all  times,  then  the 


AGE  ANNUAL  will  come  in  handy, 
because  even  so  small  an  outfit  can  be 
assembled  in   many  different   ways. 

To  tell  the  unvarnished  truth,  most 
of  the  pictures  showing  folks  listening  to 
radio  broadcasts  around  the  campfire 
are  especially  posed  for  enterprising 
photographers  and  for  home  consump- 
tion. Any  city  man  who  has  enough 
honest-to-goodness  love  of  Nature  to 
have  braved  the  mosquitoes  and  punkies, 
the  investigative  ants  and  the  too- 
neighborly  porcupines,  through  even 
two  or  three  nights  in  a  real  wilderness, 
knows  that  by  the  time  darkness  brings 
the  ideal  radio  conditions  everybody 
is  snoring  unless  there  happens  to  be  a 
poker  game  with  an  easy  mark  at  one 
corner  of  it.  He  hears  enough  of  "Red 
Hot  Mamma"  when  he  gets  back  where 
she  is  and  tries  to  explain  why  he  is  a 
week  late,  and  he  cannot  see  why  those 
who  wail  "I  Want  to  Be  Happy"  cannot 
get  that  way  without  disturbing  the 
whole  world  about  it. 

On  Being  Kindhearted 


larger    tubes   with   their   greater   output      TVEYERTHELESS,  there  are,  in  every 
of  energy  are  practicable.     It  is  unneces-  ^    out-door    jaunt,    plenty    of    oppor- 


practn 

sary  to  say  to  anyone  except  the  novice 
that  the  tube  should  remain  in  the 
original  package,  swathed  in  cotton  wool 
and  corrugated  paper,  except  when  in 
use.  The  rest  of  us  have  paid  our  five 
dollars  for  that  lesson.  The  little  Myers 
tube  is  a  glutton  for  punishment  and 
is  perhaps  the  best  for  vacation  pur- 
poses. 

Folks  generally  prefer  rheostats  that 
are  finely  variable.  They  are  especially 
desirable  in  an  out-door  outfit  which  is 
more  or  less  crudely  assembled  and  needs 
such  advantage  as  can  be  gained  without 
adding  to  the  weight.  Pressure  type 
rheostats,  and  those  made  with  sliding 
contacts  that  travel  the  entire  length 
of  a  wire,  instead  of  passing  from  turn 
to  turn,  give  finest  control. 

Some  tubes  require  only  a  single  No. 
6  dry  cell,  to  light  the  filament.  "B" 
batteries  can  be  purchased  in  small 
sizes  for  portable  outfits  where  weight 
must  be  reduced  to  the  minimum.  Very 
sensitive  phones  with  mica  diaphragms 
will  make  up,  to  some  extent,  for  the 
lack  of  amplification.  A  short  length 
of  the  aerial  wire  with  one  end  in  the 
water  or  attached  to  a  spike  driven  into 
wet  earth  provides  a  ground  connection. 

A  book  of  hook-ups  like  the  RADIO 


tunities  for  the  use  of  radio.  One  of  them 
is  in  giving  pleasure  to  humble  folks 
whose  only  contact  with  cultured  people 


from  the  centers  of  population  is  that 
provided  by  an  occasional  sportsman 
or  tourist. 

Few  city  dwellers  realize  how  scarce 
money  and  luxuries  are  in  many  rural 
areas  where  we  are  enraptured  by  the 
wealth  of  the  things  provided  by  Nature. 
Nor  can  we  who  are  buffeted  by  crowds 
from  day  to  day  appreciate  the  heart 
hunger  of  lonely  souls  who,  even  when 
they  do  meet  a  person  from  the  big 
world  outside,  are  sensitive  and  awkward 
because  they  feel  they  are  being  laughed 
at.  All  improvements  reach  those  on 
the  fringes  of  civilization  last  of  all. 
Without  going  very  far  from  town,  it  is 
always  possible  to  find,  on  the  poor 
roads,  households  where  not  even  the 
sewing  machine  has  arrived. 

I  have  visited  many  of  these.  In  one 
of  them  I  showed  a  long-haired,  bare- 
foot boy  how  to  put  up  the  aerial  and 
connect  the  apparatus  according  to  a 
wiring  diagram.  With  grand-dad  and 
parents  and  a  half  dozen  half-scared 
brothers  and  sisters  watching,  open- 
mouthed,  he  turned  on  the  juice. 

Before  my  eyes  an  epoch  in  that 
family's  history  opened.  The  announ- 
cer's voice  so  startled  the  youth  that  he 
snatched  the  phones  from  his  head, 
but  he  quickly  replaced  them,  then 
passed  them  around. 

To  each  of  the  awe-stricken,  simple- 
minded  sons  of  the  forest,  the  miracle 
was  unbelievable  but  true.  There  was 
no  sleep  in  the  house  that  night  and  before 
dawn  there  came  slipping  in  from  a 
dozen  woodland  trails  the  folks  whom 
God  forgot. 

This  obscure  family  suddenly  had 
become  a  social  center.  The  boy,  whose 
chief  claim  to  distinction  was  that  he 
could  hit  a  squirrel  or  a  revenooer  in 
the  eye  with  his  22  rifle,  could  now  shoot 
at  and  hit  far  more  distant  marks. 

The  battery  ran  low  and  that  brought 

up  the  question  of  expense.     There  were 

fresh  ones  in  the  car,  and  as  for  the  crude 

little  set,    I   told   them    I    might  call   for 

(Continued  on  page  56) 


The  wiring  diagram  for  Mr.  Perry's  simple  outdoor  radio.      Adding  a  variometer  as 
shown  above  will  make  the  set  regenerative  and  help  a  bit. 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


13 


The  top  view  of  the  portable  super,  slwiv- 
ing  arrangement  of  the  equipment  on  the 
tube  socket  sub-panel  and  the  front  panel. 


WHY  should  our  radios  be  shut 
down  when  the  balmy  days  of 
Summer  approach  and  the  fish 
start  to  bite,  when  the  great  open 
spaces  call  and  we  respond? 

Some  of  us  can  afford  to  have  a  good 
radio  receiver  at  home  and  another  in 
portable  form,  but  there  are  many  of  us 
who  cannot.  Then  there  are  those  who 
want  the  last  word  in  receivers,  both  at 
home  and  afield.  They  would  not  be 
satisfied  with  the  usual  type  of  portable 
set,  so,  after  much  searching  and  experi- 
menting, the  writer  has  at  last  found  the 
ideal  super-heterodyne  circuit  that  can 
be  built  into  a  combination  set.  It  is  a 
receiver  that  will  fit  nicely  in  the  home 
surroundings  during  the  long  Winter 
months,  and  still  be  ultra  portable  for 
Summer  week-end  trips  and  for  extended 
vacations. 

This  set  is  very  compact  and  efficient, 
utilizing  every  piece  of  equipment  to  its 
utmost,  with  some  parts  doing  dual  duty, 
as  in  the  well-known  reflex  type  of  circuit, 
so  desirous  in  portable  receivers.  Yet 
neither  tone,  volume  nor  distance  is 
sacrificed. 

This  receiver  uses  seven  "199"  tubes, 
requiring  six  dry-cell  batteries  for  fila- 
ment current  and  90  volts  "B"  battery 
for  the  plate.  Unlike  the  so-called 
"portable"  receiver,  which  is  usually  so 
unwieldy  and  heavy,  the  batteries,  loud 
speaker,  loop  and  such  accessories  in  this 


CV\  Receiver  that  Can  Be  Used  All  Year 
'Round — At  Home  and  Afield 

A    Seven-Tube    Portable 
Super-Heterodyne 

By  H.  FRANK  HOPKINS 


set  are  carried  in  one  compact  case,  frequency  is  by-passed  and  used  no  more. 
The  load  is  thus  made  evenly  balanced  However,  we  preserve  the  long  wave  or 
and  not  so  cumbersome  to  carry.  This  low  frequency  and  pass  it  on  to  the  first 
case,  when  the  set  is  used  at  home,  will  long  wave  transformer,  usually  called 
-    very    nicely   with   most   any   sur-     "intermediate    frequency"    transformer. 

There  it  is  amplified  and  passed  „to  the 
grid  of  the  first  tube,  and  now  the  first 
tube  is  doing  its  second  duty;  that  of 
amplifying  at  intermediate  frequency. 
The  first  tube  now  passes  the  inter- 
building  the  set,  let  us  analyze  the  mediate  frequency  on  to  the  primary  coil 
circuit,  so  that  we  will  know  its  good  of  the  second  intermediate  frequency 
points  and  be  better  enabled  to  under-  .transformer,  and  here  it  is  amplified  again 
stand  why  and  how  it  works  so  weii^for— through  the  remaining  two  stages  of  the 
there  is  not  doubt  it  does  work  well,  intermediate  frequency  amplifier.  It  is- 
producing  clear  tone  and  plenty  of  volume  readily  seen  that  the  first  tube  has  done 
with  surprising  _  selectivity,  making  it  two  duties;  that  of  amplification  at  short 
possible  to  tune  in  distant  stations  with-  wave  or  high  frequency  and  also  ampli- 
out_  interference  from  nearby  powerful  fication  at  long  wave  or  intermediate 
stations.  Separations  of  four  or  five  frequency, 
meters  in  wavelength  are  easy  with  this  llv 

receiver.     This  is  accomplished  by  using  Heterodyne  Action" 

transformers  that  have  been  built  with  T^HE  second  tube  has  done  the  service 
great  care  and  have  been  accurately  -*-  of  amplification  at  short  wave  or  high 
matched  and  tested,  and  are  well  shielded  frequency  and  also  has  created  a  third 
from  outside  interference  and  from  each  frequency  known  as  the  long  wave  radio 
other.  frequency  or  "heterodyne"  action.     From 

N-ow,  the  wave  emitted  from  a  broad-  the  last  intermediate  amplifier  tube  the 
casting  station  is  naturally  broad.  This  signal  is  rectified  in  the  detector  tube  and 
is  necessitated  because  of  the  presence  of  passed  to  the  audio  frequency  tubes  and 
what    are    called    "side    bands"    or    side     transformers  for  amplification  at  "audio" 


fit 

roundings  without  the  usual  array  of  a 

separate  loop,  batteries  and  reproducer. 

Analyzing  the  Circuit 

iEFORE    going    into    the    details    of 


B1 


frequencies,  which  carry  the  modulation 
of  the  voice  or  sound  being  broadcast. 
The  transformers  used  in  this  set  are 
designed  with  a  peak  of  amplification 
sufficiently    broad    to    cover    these    side 


or  voice  frequency. 

Most  super-heterodyne  receivers  em- 
ploy a  potentiometer  to  control  oscil- 
lation, by  bringing  the  grid  return 
leads    of    all     of     the     radio     frequency 


bands  or  side  frequencies  efficiently,  yet     transformers  to  the  center   point   of   th 
narrow     enough     to     perfectly    separate     potentiometer  and  adjusting  it  so   that 

a  positive  potential  is  impressed  upon 
the  grid  of  the  tubes,  thus  preventing 
oscillation.  But  in  doing  so  the  "B" 
battery  current  is  raised  considerably, 
thus  placing  an  unusually  heavy  drain 
on  the  "B"  batteries  and  materially 
shortening    their    life.     This    feature 


stations   of   four   or    five    meters    differ 
ence. 

By  referrring  to  the  circuit  diagram, 
we  find  that  the  first  tube  serves  as 
a  "short  wave"  radio  frequency  ampli- 
fier. This  is  a  feature  not  usually  incor- 
porated   in    super-heterodyne    combina 


tions,  and  makes  for  very  efficient  long  unnecessary  in  this  set,  as  the  intermedi- 
distance  reception.  The  grid  of  the  first  ate  frequency  transformers  are  "neutral- 
tube  accepts  the  signal  picked  up  by  the  ized"  so  that  the  tubes  will  operate 
loop  or  antenna  and  passes  it  to  the  short  equally  as  efficient  with  a  negative  grid 
wave  radio  frequency  transformer,  where  bias  through  a  4J^  volt  "C"  battery, 
it  is  amplified  and  passed  to  the  grid  of  The  use  of  the  "C"  battery  in  the  grid 
the  second  tube.  This  tube  serves  as  a  circuit  reduces  the  drain  on  the  "B"  bat- 
rectifier  and  frequency  changer,  thereby  teries  and  greatly  prolongs  their  life, 
doing  double  duty.  There  is  no  loss  of  While  the  average  seven  tube  radio- 
efficiency  in  this  arrangement,  and  a  receiver  draws  around  50  milliamperes 
saving  of  one  tube  is  effected.  The  out-  of  "B"  battery  current,  this  set  operates 
put  of  the  frequency-changing  tube  has  around  ten  milliamperes,  and  no  potenti- 
two   frequencies;    one    of   short    wave    or  ometer  is  necessary. 

high  frequency,  and  one  of  long  wave  or         Volume  is  controlled  by  a  60-ohm  rheo- 

low   frequency.     The    short    wave,    high  stat  in   the   filament   circuit   of  the   first 


14 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Fig.  2 


Rear  view  of  Mr.  Hopkins'  receiver,  showing  the  assembly  of  the  sub-panel,  including  the  transformers,  which  an  so  arranged  as  to  con- 
serve the  maximum  amount  of  space  and  make  the  set  truly  portable  as  well  as  compact. 


intermediate  frequency  amplifier  tube, 
the  intermediate  frequency  transformers 
being  so  well  balanced  or  neutralized  that 
there  is  no  tendency  toward  oscillation. 

When  a  regenerative  loop  is  used,  the 
strength  of  the  signal  impressed  upon  the 
first  tube  is  greatly  increased.  This  is 
accomplished  by  a  capacitative  coupling 
between  the  grid  and  plate  of  the  first 
tube. 

Feedback  is  obtained  by  a  midget 
variable  condenser  to  the  center  of  the 
loop.  A  regenerative  loop  is  a  loop  hav- 
ing two  windings  running  in  the  same 
direction,  parallel  to  one  another,  and 
tapped  in  the  center.  Another  unusual 
feature  of  this  receiver  is  the  design  of 
the  transformers.  All  of  them  are  en- 
closed in  drawn  brass  cases,  which  com- 
pletely shield  the  windings  from  outside 
interference  and  prevent  internal  coup- 
ling and  oscillation.  The  windings  are 
all  well  impregnated  with  a  high  grade 
insulating  compound  which  prevents 
moisture  absorption  and  protects  the 
windings  from  damage  through  rough 
handling. 

The  first  transformer  (R-201)  is  a  long 
wave,  radio  frequency  transformer  having 
a  peak  of  amplification  sufficiently  sharp 
to  permit  close  and  accurate  tuning  with- 
out the  elimination  of  the  "side  band" 
frequencies  which  are  so  necessary  to 
true  tonal  reproduction.  This  trans- 
former is  peaked  bv  two  fixed  condensers 
(.0001  and  .001.) 

The  second  transformer  (R-202)  is  a 
radio  frequency  transformer  having  high 
amplification  as  low  as  225  meters  and  as 
high  as  700  meters. 

The  third  transformer  (R-203)  is  a 
long  wave,  radio  frequency  transformer. 
The  fourth  group 
(R-200),  contains 
three  intermediate 
frequency  transfor- 
mers whose  curve 
covers  a  wide  band 
of  frequency.  The 
fifth  and  last  group 
(R-204)  contains 
two  audio  frequen- 
cy transformers 
completely  shielded 
and  of  as  high  am- 
plification ratio  as  A  front  panel  view 
is    consistent     with 


LIST  OF  MATERIALS   FOR   THE 
PORTABLE  SUPER-HET 

1  R-200,  3-stage  tuned  radio  frequency  trans- 
former. 

1  R-201,  long  wave  radio  frequency  trans- 
former. 

1  R-202  short  wave,  radio  frequency  trans- 
former. 

1  R-203,  long  wave  radio  frequency  trans- 
former. 

1  R-204,  2  stage,  radio  frequency  trans- 
former. 

2  .0005  variable  condensers  and  dials,  vernier 
adjustment.     (VC  and  WC). 

1  Midget  variable  condenser,  maximum 
capacity  .0001  mfd.  (LC). 

7  Type  199  tube  sockets,  spring  base. 
1  30-ohm  rheostat  (TR). 

1  60-ohm  rheostat.  (VR). 

2  .001  mfd.  mica-fixed  condensers  (A  and  B). 
2  .005  mfd.  mica-fixed  condensers  (E  and  F). 
1  .0001  mfd.  mica-fixed  condenser  (C). 

1  .00025  mfd.  mica-fixed  condenser  (D). 

2  grid  leak  mountings  (for  FG'and  VG). 

1  Tubular  grid  leak  (2  to  7  megohms,  to 
suit  tube  used.)     (FG). 

1  Variable  grid  leak,  (200,000  to  300,000 
ohms.)      (VG). 

1  Single  circuit  jack  (LP). 

1  Two-circuit  jack  (DP). 

1  "A"  Battery  switch  (S). 

1  Panel  mounting  ammeter  .0  to  1.8  scale  (if 
desired). 

3  Single  contact  jacks  and  plugs  for  loop 
terminals  (No.  1,  2,  3). 

5  Binding  posts  (  A+ ,  A — ,  B — ,  B45 ,  and  B+). 
1  front  panel,  (7"  x  22"  x  r*"). 
1  Transformer  sub  panel  (4U"  x  21"x  rV"). 
1  Socket  sub  panel  (2K"  x  21"  x  A")- 

1  Binding  post  strip  (2"  x  6"  x  fV"). 

4  Brass  brackets  for  supporting  front  panel 
to  sub  panel  assembly. 

2  Brass  spring  clips  for  supporting  "C" 
battery. 

1  4U-volt  "C"  Battery. 

Miscellaneous  screws,  nuts,  spacers,  wire, 
terminals,  solder,  etc. 

1'2"  x  i'2"  brass  angle,  12"  long  for  stiffening 
transformer  sub  panel. 

1  cabinet  or  case,  to  fit  7"  by  22"  panel  as 
desired. 


of  the  portable  super-heterodyne,  showing  the 
controls  and  the  ammeter  for  filament  current. 


good  tonal  quality.  The  circuit  diagram, 
together  with  the  views  of  the  assembled 
set,  gives  a  very  accurate  idea  of  the 
method  of  mounting  the  parts  of  the  re- 
ceiver. When  set  is  laid  out  as  shown, 
all  leads  can  be  run  in  the  shortest 
distance  and  no  trouble  need  be  expected 
from  feed-back  or  capacity  in  the 
wiring. 

The  list  of  parts  to  build  the  set  is 
given  in  an  accompanying  column.  All 
of  the  parts  bear  the  same  designating 
letters  and  numbers  as  are  used  in  the 
diagram  and  throughout  this  article. 
This  is  to  better  enable  the  prospective 
builder  to  identify  each  part  more  easily 
and  to  aid  him  in  mounting  and  wiring 
the  equipment. 

Layout  of  Panels 

WHEX  all  of  the  parts'are  secured,  we 
can  lay  out  and  drill  the  transformer 
sub-panel,  the  socket  sub-panel,  and  the 
front  panel,  to  mount  the  apparatus  as 
shown  in  the  views  of  the  set.  This  is 
best  done  by  placing  the  parts  in  their 
respective  places  and  marking  the  mount- 
ing holes  with  a  punch  or  sharp  awl. 
These  holes  should  be  drilled  a  bit  larger 
than  actually  required,  so  as  to  prevent 
the  mounting  screws  from  binding  when 
lining  up  the  parts. 

In  preparing  the  tube  socket  panel,  we 
will  drill  two  holes  for  each  socket,  in  ad- 
dition to  those  required  for  mounting  the 
sockets.  They  will  line  up  with  the  fila- 
ment terminals  of  the  tube  sockets.  The 
filament  terminals  will  be  removed  from 
the  sockets  and  replaced  when  the  sockets 
are  mounted,  so  that  the  nut  or  terminal 
side  is  below  the  sub-panel,  making  it 
possible  to  run  the  filament  current  or 
power  leads  away 
from  the  high  fre- 
quency leads. 

When  the  trans- 
former sub-panel  is 
drilled,  it  should  be 
stiffened  by  mount- 
ing the  y2"  by  y2" 

x  12"  brass  angle  on 
the  reverse  side  to 
the  transformers,  in 
line  with  the  center 
of  the  sub-panel,  as 
tuning  and  volume  noted  in  Fig.  1.  The 
transformers      and 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


15 


grid  mountings  will  then  be  fastened  to 
the  panel  and  we  are  ready  to  assemble 
the  two  sub  panels. 

The  two  sub  panels  are  assembled  with 
six  No.  6  brass  machine  screws  and  nuts, 
1J4"  long,  mounting  the  socket  sub-panel 
directly  over  the  W  angle  and  using  J'!" 
spaces  between  the  two  sub  panels  as 
noted  in  Fig.  2. 

The  two  variable  condensers  (VC)  and 
(WC)  will  be  mounted  to  the  front  panel 
as  will  be  the  two  jacks  (LP  and  DP), 
the  three  loop  jacks  (Nos.  1,  2  and  3), 
the  battery  switch  (S)  and  the  ammeter, 
if  an  ammeter  is  to  be  included.  Now 
we  will  lay  this  panel  aside  until  most  of 
the  wiring  is  completed  for  the  sub-panels. 

It  will  be  well  to  run  all  of  the  connec- 
tions possible  on  the  sub  panel  assembly, 
before  mounting  the  front  panel,  as  most 
of  the  wiring  is  required  here,  making  it 
much  easier  to  reach.  The  set  wrill  be 
wired  with  sixty-strand,  double  silk 
covered  copper  wire,  except  where  the 
fixed  condensers  are  to  be  supported. 
For  this  we  will  use  bus  wire  covered  with 
a  good  insulator  such  as  spaghetti. 

When  mounting  the  fixed  condenser, 
(C),  be  sure  to  place  it  at  least  two  inches 
or  more  from  all  other  wires  or  trans- 
formers. If  it  is  too  close,  coupling  is 
liable  to  take  place  between  the  plate 
circuit  and  grid  circuit  of  the  first  tube, 
causing  noise  or  making  it  hard  to  tune 
properly. 

Ordinary  Loop  Possible 

THE  front  panel  will  be  mounted  to 
the  sub  panel  assembly  when  this 
wiring  is  completed  and  the  parts  con- 
nected up.  The  four  brass  brackets  will 
be  used  for  his  purpose,  as  shown  in  the 
views  of  the  completed  set.  A  regenera- 
tive loop  should  be  used  with  this  set  for 
best  results,  as  covered  earlier  in  this 
article.  However,  an  ordinary  loop  may 
be  used  by  connecting  one  terminal  to 
loop  jack  No.  1  and  the  other  terminal 
to  loop  jacks  No.  2,  and  3. 


An  antenna  may  also  be  used  if  desired, 
but  a  two-circuit  coil  will  be  required  for 
this.  It  should  be  wound  on  a  3"  diame- 
ter tube.  The  primary  is  to  have  eight 
turns  of  No.  22  double  silk  covered  copper 
wire,  wound  in  an  even  layer,  one  end  to 
be  connected  to  the  antenna  and  the  other 
to  a  good  ground.  The  secondary  coil 
will  have  fifty  turns  of  the  same  wire 
wound  in  the  same  direction  on  the  same 
tube,  one  end  to  be  connected  to  looo 
jack  No.  1  and  the  other  to  loop  jacks 
No.  2  and  3. 

The  set  is  made  ready  for  operation  by 
connecting  the  six  dry  cells  in  series 
multiple;  that  is,  two  sets  of  three  cells 
connected  in  series  and  the  positive 
terminals  of  each  set  connected  to  binding 
post  A  +  ,  and  the  negative  terminals 
to  binding  post  A — .  The  90  volts  of  B 
battery  wrill  be  connected  in  series  and 
the  negative  terminal  connected  to  bind- 
ing post  B — ,  taking  a  tap  off  at  45  volts 
and  connecting  it  to  binding  post  B45, 
the  90  volt  positive  lead  to  be  connected 
to  the  binding  post  B+. 

Tuning  is  very  simple.  It  is  done  by 
the  two  dials  (YC  and  WC)  and  by 
moving  the  loop  in  an  arc  of  180  degrees. 

The  midget  condenser  (LC),  when  once 
adjusted,  need  not  be  changed.  Volume 
is  controlled  by  the  rheostat  (VR)  and 
when  the  set  is  once  logged,  one  can  be 
certain  that  when  he  turns  his  loop  and 
two  dials  (YC  and  WC)  to  the  same  setting 
he  will  get  the  same  station — if  it  is  on 
the  air,  as  this  setting  does  not  vary  when 
properly  built  and  operated. 

Logging  the  Set 

To  prepare  an  accurate  log  of  the  dial 
settings  of  condensers  YC  and  WCit  will 
be  well  to  secure  the  regular  cross  section 
paper  usually  used  for  this  purpose  and 
plot  a  curve  for  each  dial.  This  can  be 
done  by  first  tuning  a  station  to  its  best 
maximum  setting  on  the  true  wave  and 
spotting  a  point  on  the  chart  for  each 
dial,   corresponding  to  the   point   of  the 


dial  and  the  wavelength  cf  the  station. 
For  example,  suppose  we  tune  in  a  sta- 
tion whose  wavelength  is  three  hundred 
meters;  the  setting  of  dial  VC  will  be  ap- 
proximately 5-32.  That  is,  the  sliding 
element  of  the  condenser  w-ill  be  pulled 
out  until  number  five  is  in  line  with  the 
dial  and  the  dial  rotated  until  it  reads 
thirty-two.  This  will  be  spotted  on  the 
chart  for  dial  VC  at  three  hundred  meters 
on  the  vertical  scale  and  fifty-three  on  the 
horizontal  scale. 

The  same  procedure  will  be  followed  for 
the  dial  WC.  The  rheostat  dials  need 
not  be  logged,  as  they  will  vary  as  the 
filament  batteries  grow  weaker. 

QUITE  an  improvement  may  be  made 
in  the  results  obtained  by  this  set  if 
the  tubes  are  matched.  This  maybe  done 
by  using  a  tube  tester  similar  to  that 
described  by  the  wirter  in  the  May  issue 
of  RADIO  AGE. 

If  no  tube  tester  is  available,  the  next 
best  way  to  match  them  would  be  to 
tune  in  a  station,  and  then  by  shifting 
the  tubes  until  the  best  results  are  ob- 
tained, with  the  smallest  filament  cur- 
rent  drain. 

The  tubes  should  then  be  marked  so 
that  they  will  be  put  back  in  their  proper 
places  in  the  circuit  when  once  removed. 
A  tube  whose  characteristics  vary  to  a 
very  great  extent  from  those  used  for  a 
like  purpose  on  the  same  filament  con- 
trol, will  cause  considerable  noise  in  the 
set  and  sometimes  will  be  the  direct 
cause  of  aging  the  other  tubes  by  requir- 
ing excessive  filament  current  to  be  sup- 
plied to  the  circuit  to  make  this  tube 
operate. 


Note:  It  would  be  advisable  to  communi- 
cate with  the  writer  in  care  of  RADIO  AGE 
before  starting  to  build  this  set,  and  secure 
a  detailed  list  of  parts  as  used  in  the 
original  receiver.  Detailed  panel  layouts 
and  bracket  dimensions  may  be  had  at 
cost  if  desired. 


"/99"  TY/>£    TUBES 


/r/GU/?£  1 


16 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


The  best  hookup  for  the  double  grid  tube   is  one   where    regeneration 
and  reflexing  are  combined.       Above  is  a  typical  circuit  of  this  type. 


The  Double-Grid  Tube  in  Ordinary  Sets 

Low  Voltage 

In  Regenerative 

And  Reflex 

Receivers 

By  C.  R.  BLUZAT 

IN  the  first  part  of  this  article,  pub- 
lished in  the  March  RADIO  AGE, 
use  was  made  of  only  the  plate 
characteristic  of  the  tube,  the  extra  grid 
being  merely  used  as  a  means  of  cutting 
down  the  resistance  of  the  plate  filament 
space.  The  benefit  consisted  in  a  low 
plate  potential  to  obtain  a  good  utiliza- 
tion of  the  tube.  If  we  increase  the 
plate  voltage,  the  inner  grid  voltage 
being  constant,  we  obtain  a  family  of 
curves  very  similar  tothatobtainedforthe 
ordinary  three-electrode  tube,  the  steep- 
ness of  the  plate  current  curve  increasing 
as   the   plate   potential  is  increased. 

This  is  an  important  feature,  as  the 
steepness  of  these  curves  is  a  measure  of 
the  amplification  factor;  the  steeper  the 
curve,  the  bigger  the  amplification  factor 
and  the  more  efficient  is  the  tube  as  a 
straight  amplifier  or  as  a  regenerative 
detector. 

Referring  to  Fig.  1  of  the  first  part  of 
the  article,  we  notice  that  the  inner 
grid  current  curve  is  very  similar  to  the 
plate  current  curve.  This  means  that 
the  tube  may  also  be  used  with  this  grid 
playing  the  part  of  a  plate. 

Hookups  for  the  ordinary  tube  apply 
readily  to  the  two  grid  tube,  tying  the 
"B"  battery  voltage  to  the  inner  grid  and 
disregarding  the  plate,  low  voltage  "B" 
battery  being  used.  But  the  fact  that 
the  inner  grid  current  curve  is  similar  to 
the  plate  current  curve  enables  one  to 
use  both  inner  grid  and  plate  in  an  am- 
plifying role. 

The  theory  shows  indeed  that,  in  an 
oscillary  state,  the  maximum  power  de- 
livered by  either  grid  or  plate  is  VI 
divided  by  2,  V  being  the  average  voltage; 
I  the  average  current. 

Thus,  if  both  circuits  are  used  together, 
the  output  will  be  about  VI  if  the  proper 
point  of  functioning  is  used. 

For  the  same  reason,  use  of  both  cir- 
cuits is  very  advantageous  for  reception. 

Getting  Full  Efficiency 

FIG.  1  shows  a  hookup  where  the  full 
efficiency  of  the  tube  is  obtained. 
LI  and  CI  are  the  secondary  circuit. 
L2  and  L3  are  two  inductances  respec- 
f'vely  connected  to  the  inner  grid  and 
the  plate.  The  electromagnetic  coupling 
between  L2,  L3  and  LI  is  variable  and 
the  coils  act  to  give  a  double  regenera- 
tion. With  such  a  combination,  as  low 
as  6  volts  for  the  "B"  battery  will  not 
cut  the  volume  of  the  reception  in  an 
appreciable  manner. 

The  operation  of  the  set  will  be  very 
similar  to  an  ordinary  regenerative  hook- 


up as  LI  and  L2  act  like  two  ticklers. 
LI  and  CI  are  the  same  as  the  usual 
found  in  the  ordinary  receiver  to  cover 
the  broadcasting  range.  L2  and  L3 
should  be  about  80  microhenries.  Such 
an  inductance  value  will  be  obtained  by 
winding  30  turns  of  No.  18  wire  on  a  tube 
3  inches  in   diameter. 

The  width  of  the  winding  will  be  about 
one  and  a  half  inch  if  double  cotton 
covered  wire  is  used.  If  spider  webs  are 
preferred,  they  may  be  used,  the  number 
of  turns  to  get  the  same  inductance  being 
about  the  same  as  above  if  the  inside 
diameter  of  the  winding  is  the  same  as 
the  diameter  of  the  tube.  Honeycomb 
coils  may  also  be  used — for  the  secondary 
and  the  two  ticklers;  the  aperiodic 
primary  being  obtained  by  winding  about 
10  turns  on  top  of  the  secondary  honey- 
comb coil. 

The  double  grid  tube  may  also  be  used 
in  reflex  circuits.  The  more  efficient 
hookup  is  one  where  regeneration  and 
reflexing    are    combined.     Fig.    2    is    a 


Fig.  1 


A  simple  hookup  of  the  regenerative  type, 
where  the  full  efficiency  of  the  double  grid 
tube  is  utilized.  As  low  as  6  volts  for  the 
"B"  battery  will  not  cut  the  volume  of  the 
reception  appreciably  in  this  hookup. 


typical  circuit  of  this  class.  Detection 
is  obtained  in  the  usual  fashion  with 
the  grid  condenser  and  leak,  this  function 
being  performed  by  the  control  grid. 
Regeneration  is  obtained  through  the 
action  of  the  tickler.  The  detected 
current  goes  through  the  primary  of 
the  audio  transformer..  The  audio  fre- 
quency voltage  is  stepped  up  in  the 
secondary  winding  and  this  amplified 
voltage  is  applied  to  the  inner  grid. 
This  voltage  in  turn  causes  greater 
variations  of  current  in  the  plate  circuit 
of  the  tube  and  it  is  this  amplified  current 
which   actuates   the   receiver. 

'"PHE  .002  microfarad  condenser  is  a 
-L  by-pass  condenser  for  the  radio 
frequency  current  in  the  plate  circuit. 
The  values  of  inductances  and  condensers 
are  much  the  same  as  in  an  ordinary 
reflex  circuit.  The  circuit  is  shown 
with  no  "B"  battery,  as  good  results 
may  be  obtained,  and  also  to  emphasize 
the  simplicity  of  the  set.  The  plate, 
being  tied  to  the  positive  post  of  the 
"A"  battery,  is  at  a  slightly  higher 
potential  than  the  middle  of  the  fila- 
ment; if  the  voltage  of  the  "A"  battery 
is  6v  and  the  drop  in  the  rheostat  is  2v, 
the  plate  is  4v  more  positive  than  the 
middle  of  the  filament. 

This  positive  voltage  is  enough  to 
secure  good  results.  The  inner  grid  is 
tied  to  the  arm  of  a  200  ohm  potentio- 
meter and  its  potential  as  regards  the 
filament  may  be  adjusted  by  moving  the 
potentiometer  knob.  This  hookup  will 
be  more  efficient,  of  course,  if  a  higher 
voltage  is  impressed  on  the  plate,  but 
the  no  "B"  battery  feature  is  important, 
as  it  is  a  great  step  toward  the  simplifi- 
cation of  the  set.  The  tube  is  of  the  low 
consumption  type,  requiring  only  .35 
A  and  3v8.  This  current  is  low  enough 
to  be  furnished  by  dry  cells,  three  being 
used  in  series  to  give  the  necessary 
voltage.  An  efficient  one-tube  portable 
set  may  be  made  following  the  hookup 
of  Fig    2. 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


17 


A  SCIENTIFIC  RECEIVER 

By  M.  B.  Sleeper 


Fig.  1.  Looking  from  the  top  of  the  new  Browning-Drake  Receiver, 
showing  the  general  arrangement  and  the  simplified  wiring,  which 
makes  this  set  popular  with  beginners  who  want  to  bttild  a  set  and 
build  it  quickly. 


Mathematical  Determination  of  Constants  of  Coils 
and  Condensers  a  Feature  of  Browning-Drake  Set; 
Has  Half  as  Many  Connections  as  Ordinary  5-Tuber 


WHEN  Messrs.  Browning  and 
Drake  delivered  a  lecture  on  their 
work  before  a  gathering  of  radio 
engineers  some  time  ago,  it  is  doubtful 
if  either  of  them  had  any  conception  of 
the  unusual  popularity  that  their  set 
was  destined  to  receive  within  the 
course  of  a  few  months.  The  Browning- 
Drake  receiver  is  all-popular  in  the  New 
England  States  and  its  popularity,  based 
on  sheer  merit,  is  growing  day  by  day. 

The  Browning-Drake  does  not  employ 
a  trick  hookup.  Its  success  is  due  to  the 
scientific  methods  applied  in  determining 
mathematically  the  various  constants  of 
the  coils  and  condensers  when  used  with 
the  vacuum  tubes  now  available.  This 
can  be  seen  by  studying  the  circuit  dia- 
gram in  Fig.   4. 

A  special  feature  of  this  new  re- 
ceiver is  that  it  has  about  half  as 
many  connections  as  an  ordinary  five- 
tube  receiver.  Therefore,  it  is  a  par- 
ticularly fine  outfit  for  the  beginner  or 
for  the  set  builder  who  wants  something 
that  can  be  constructed  very  quickly. 
As  a  Summer  time  proposition,  this  is  an 
ideal  outfit  because  it  can  be  operated 
with  a  small  indoor  antenna,  with  cor- 
respondingly   lower    static    pick-up. 

Tests  on  this  outfit  settled  definitely 
the  question  of  B  battery  consumption. 
With  five  tubes  in  operation,  under 
normal  receiving  conditions,  the  total 
plate  current  was  10  milliamperes.  Five- 
tube  neutrodynes,  for  example,  draw 
20  to  30  milliamperes.  This  is  a  positive 
evidence  that  the  resistance  coupled 
amplifier  draws  less  current  than  the 
transformer  type.  Moreover,  when  strong 
signals  come  in,  the  current  is  decreased 
and  not  increased. 


The  publication  of  complete  con- 
struction data  for  these  receivers  has  re- 
sulted in  a  demand  for  a  set  of  this 
kind  employing  resistance  coupled  audio 
amplification,  and  representing  one  of 
the  highest  types  of  radio  receivers  in 
use  today,  combining  as  it  does  the  ex- 
treme sensitivity  and  selectivity  peculiar 
to  this  set,  with  a  faithfulness  of  repro- 
duction, through  the  use  of  resistance 
amplification,  which  will  satisfy  even, 
the    most    critical    music    lover. 

Construction  Very  Simple 

By  using  a  Daven  Super-Amplifier  unit 
which  comes  already  wired,  the  construc- 
tion of  the  set  has  been  made  very  simple 
and  neat,  without  any  appreciable  in- 
crease in  cost.  Practically  all  of  the 
wiring  has  been  kept  under  the  tube 
panel,  adding  greatly  to  the  appearance  of 
the  outfit  when  installed  in  a  cabinet. 

The  tuning  is  accomplished  by  means 
of  the  two  large  vernier  dials.  The  one 
on  the  left  tunes  the  R.  F.  amplifier  while 
the   right   hand   dial  tunes  the  detector. 

The  R.  F.  amplifier  tube  filament  is 
regulated  by  a  30-ohm  rheostat.  One 
of  20  ohms  controls  the  detector,  and 
another,  of  6  ohms,  is  connected  to  the 
three  A.  F.  amplifier  tubes.  Tri-jacks 
are  used  for  plugging  in  on  the  detector 
or  last  A.  F.  stage.  Below  the  center 
rheostat  dial  is  a  filament  switch,  by 
means  of  which  the  tubes  can  be  turned 
on  or  off  without  disturbing  the  rheostat 
settings.  This  switch  is  provided  with 
an  ON-OFF  sign  which  fits  against  the 
panel,  and  the  fact  that  its  depth  behind 
the  panel  is  very  small  makes  it  just  right. 

The  Browning-Drake  receiver  will  not 
interfere  with  reception  of  other  stations, 


because  the  detector  tube  is  not  used  in 
an  oscillating  condition,  and  the  R.  F. 
tube  does  not  oscillate  at  all. 

Standard  Parts  Required 

T^HE  front  panel  is  of  Formica  measur- 
■*-  ing  7  by  28  by  3-16-in.,  and  the  base 
panel,  of  the  same  material,  measures 
3^2  by -23 -by  3-16-in.  The  panels  must 
be  strong  ■  mechanically  because  they 
support  the  weight  of  the  instruments 
arid"  any  extreme  bending  or  sagging  will 
probably  result  in  open  or  short  cir- 
cuited   connections. 

The  two  tuning  units  come  already 
assembled  with  the  coils  mounted  on 
the  condensers.  The  first  unit  consists 
of  a  0.0005  mfd.  condenser  with  the 
antenna  coil,  while  the  second  is  made 
up  of  a  0.00035  mfd.  condenser  with  the 
radio  frequency  coil.  Both  of  the  con- 
densers are  provided  with  vernier  dials. 
These  dials  have  a  reduction  ratio  of 
about  5  to  1,  and  are  perfectly  smooth 
and  positive  in   operation. 

On  the  front  panel  are  mounted  the 
three  rheostats,  battery  switch,  and  two 
Tri-jacks.  The  base  panel  carries  the 
amplifier  unit,  one  standard  socket,  one 
199  socket,  a  0.001  mfd.,  a  fixed  con- 
denser, and  a  0.00025  mfd.  fixed  con- 
denser with  gridleak  mounting  clips  for 
the  2-megohm  gridleak.  Three  binding 
posts  are  used  on  the  antenna  coil. 

For  hardware,  one  angle  bracket  and 
twelve  coil  mounting  pillars  are  required. 
One  of  the  pillars  holds  the  tube  panel 
to  the  front  panel  at  the  right  hand  end: 
nine  of  them  are  used  for  extending  con- 
nections from  the  amplifier,  while  the 
other  two  are  fastened  to  the  underside 
of  the  tube  panel  as  supports,  for  they 


18 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Fig.  2.  A  picture  of  the  wiring  arrangement  of  the  Browning-Drake  set.    By  bringing 
the  terminals  from  the  amplifier  to  the  under  side  of  the  base  panel,  most  of  the  wiring  is 

kept  out  of  sight. 


rest  on  the  bottom  of  the  cabinet  when 
the   set  is  installed. 

Fig.  2  gives  the  picture  wiring  for  the 
set.  It  shows  the  connections  and  wiring 
exactly  as  they  were  arranged  in  the 
original  receiver.  The  base  panel  is 
dropped  down  in  order  to  show  the  parts 
more  clearly. 

Put  soldering  lugs  on  the  terminals  of 
the  various  instruments  as  you  mount 
them.  The  short  heavy  lines  in  the 
picture  wiring  diagram  show  the  direc- 
tions in  which  these  lugs  must  point. 
Use  a  good  rosin  core  solder,  or  plain  soft 
solder  with  paste  put  on  very  sparingly. 
We  have  found  that  the  familiar  spread- 
ing of  the  soldering  paste  over  the  panel 
at  each  connection  can  be  eliminated 
entirely  by  slipping  a  small  piece  of 
ordinary  newspaper,  which  is  quite 
absorbent,  under  each  lug  while  the 
soldering  is  being  done.  The  paper 
absorbs  the  soldering  paste,  leaving  a 
clean,  neat  connection.  Have  the  iron 
thoroughly  tinned  and  hot  enough  to 
make  the  solder  flow  freely.  If  you  can- 
not afford  an  electric  soldering  iron,  you 
can  use  a  soldering  kit,  which  comes 
complete  at  a  low  cost. 

1.  Remove  the  nut  under  the  binding 
post  marked  P  input  on  the  amplifier. 
Also  remove  the  short  connecting  strip 
to  the  screw  holding  the  end  resistor  clip. 
Put  the  nut  back,  and  on  top  ot  it,  screw 
a  coil  mounting  pillar.  This  will  be  the 
+  90V  binding  post.  Remove  the  screw 
which    fastens   the   clip   of   this   resistor, 


enlarge  the  hole  in  the  clip  and  amplifier 
base,  and  slip  in  a  J^-in.  6-32  R.  H. 
screw.  Put  a  nut  and  a  coil  mounting 
pillar  on  the  screw  underneath  the  base. 
This  will  be  terminal  No.  28  later. 

Remove  nut  under  binding  post,  B 
Input,  on  Daven  Super-Amplifier.  Dis- 
connect connecting  bus  going  to  this  post, 
and  put  back  the  nut  and  a  coil  mounting 
pillar.  This  will  be  the  Det+  binding 
post.      Now  remove  the  bus  wire  which 


top  of  it.  This  will  be  terminal  22  later. 
Remove  the  screw  and  nut  which 
fasten  the  front  clip_'of  the  second  resistor 
from  the  right  of  the  amplifier.  Enlarge 
the  hole  in  both  the  clip  and  the  base, 
and  put  in  a  3^-in.  6-32  R.  H.  screw. 
Put  a  nut  and  a  coil  mounting  pillar  on 
this  screw  under  the  base.  This  will  be 
terminal    16. 

Screw  a  coil  mounting  pillar  on  the 
A  Bat+  binding  post  screw  under  the 
base.  This  will  be  terminal  33.  Repeat 
this  with  the  P  output  and  B  output 
binding    posts. 

PUT  a  1-2-in.  6-32  R.  H.  screw  through 
■*-  the  front  left  hand  mounting  hole  of 
the  amplifier.  This  is  a  "blind"  screw. 
Fasten  the  angle  bracket  to  the  tube 
panel  in  the  position  shown  with  a  1-2-in. 
6-32  F.  H.  screw  and  nut.  Now  fasten 
the  amplifier  to  the  tube  panel  with  three 
lj^-in.  6-32  R.  H.  screws  and  nuts.     Put 


pin- 
holes 


6-32    R.    H.    screws   through    the 
the    tube    panel    into    the    coil 


Fig.    3.    The   clean  cut  design  of  the   Browning-Drake  five-tube   receiver,  so  free  from 
complicated  wiring,  makes  the  set  unusually  attractive  as  well  as  efficient  for  all  kinds  of 

radio  reception. 


ran  from  this  post  to  the  front  clip  of 
the  first  resistor.  Enlarge  the  hole  in 
this  clip  and  the  amplifier  base  and  put 
in  a  M-in.  6-32  R.  H.  screw.  Put  a  nut 
and  a  coil  mounting  pillar  on  this  screw 
under  the  base.  This  will  be  terminal 
26  later.  Remove  the  nut  under  the 
binding  post  marked  A  Bat—,  discon- 
nect and  remove  the  bus  wire  which  runs 
over  to  the  A—  feeder  bus,  and  put  back 
the  nut   with   a  coil   mounting  pillar  on 


mounting  pillars  under  the  amplifier  base. 
These  serve  to  bring  the  connctions  up 
to  the  amplifier.  Put  the  necessary  lugs 
under  the  heads  of  these  screws,  as  shown 
in  the  bottom  view,  Fig.  3,  of  the  set. 
When  putting  in  the  screws  for  terminals 
26  and  28  be  sure  to  fasten  the  tabs  on  the 
0.001  mfd.  fixed  condenser  with  them. 
2.  Remove  the  screws  and  nuts  from 
the  -1-  and  —  terminals  of  the  201-A 
(Turn  to  page  50) 


ill 


Fig.  4. 
CIRCUIT  WITH  RESISTANCE    COUP.  A,E 


A-        A+       B+       B*       B+ 

B-      B.F.      OCT.      AMR 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


19 


oo   o  o  oo 


^BINDING    POSTS 


GRID    LEAK 
—     ANO 
CONDENSER 


23  PLATE 
(CONDENSER 


FIGURE       1+ 
GENERAL    LAYOUT     Or  PARTS 


IN  building  an\ 
kind  of  a  set 
which  employs 
radio  frequency 
amplification,  the 
one  essential  fea- 
ture is  to  provide 
some  way  to  over- 
come the  oscilla- 
tions of  the  radio 
frequency  amplifi- 
er. This  type  of 
a  mplificatio  n 
is  absolutely  nec- 
essary if  the  best 
results   are   to    be 

expected.  It  is  very  true  that  some  re- 
generative sets  which  are  not  equipped 
with  high  frequency  amplifiers  will  pro- 
duce remarkable  results  in  some  cases,  but 
for  all-round,  continuous  performance, 
there  is  nothing  to  be  compared  with 
radio  frequency  amplification. 

There  are  several  ways  of  overcoming 
these  undesired  oscillations,  but  the 
method  used  by  Mr.  Roberts  is  one  of  the 
most  dependable.  In  accomplishing  this, 
he  makes  use  of  a  primary  winding  con- 
sisting of  two  wires  wound  together, 
which  really  forms  two  coils  wound  in  the 
same  direction;  as  the  turns  of  these  coils 
lay  side  by  side,  they  are  very  effective. 

Only  one  of  these  windings  is  used  for 
the  primary,  similar  to  the  primary  in 
other  radio  frequency  sets,  and  the  pur- 
pose of  the  other  is  to  prevent  oscillations. 

The  coil  which  is  used  as  the  primary 
is  connected  in  such  a  way  that  it  is  op- 
posed in  inductive  relation  to  the  one 
which  is  used  to  neutralize  the  feed-back. 
This  neutralizing  coil  is  connected  to  the 
grid  through  a  condenser,  as  will  be 
noticed  upon  looking  over  the  drawing 
shown  in  Figure  2,  which  is  a  schematic 
arrangement  of  the  circuit. 

Mounting  the  Coils 

IN  Figure  3,  a  simple  method  of  mount- 
ing the  coils  is  shown.  Coils  3  and  4 
are  the  two  parallel  windings  mentioned 
before,  and  are  wound  on  one  form.  This 
form  is  fastened  to  a  wooden  block,  "A," 
which  has  a  slotted  hole  for  the  screw 


Overcoming  Radio  Frequency 

Oscillations  in  the 

ROBERTS  RECEIVER 

By  FRANK  D.  PEARNE 


which  is  to  hold  it  to  the  baseboard,  and 
which  will  allow  a  slight  shifting  of  the 
position  of  these  coils  in  relation  to  the 
others.  The  secondary,  which  is  coil  "5," 
is  mounted  in  a  permanent  position  on 
the  end  of  the  wooden  block,  "B,"  and 
the  tickler  ~coil,  which  is  adjustable,  is 
mounted  on  the  end  of  a  long  wooden 
dowel  pin  which  extends  through  the 
wooden  support  "C"  and  through  the 
panel,  where  it  terminates  in  a  knob  by 
means  of  which  the  coil  is  drawn  forward 
or  back  to  vary  the  coupling-  between  it 
and  the  secondary  coil. 

One  of  the  slots  in  l.je  fiber  form  on 
which  the  tickler  coil  is  wound  is  made  to 


FIGURE  1 

SHOWING       DIMENSIONS     OF      FIBEP 
FORM    FOR    COILS     I-2-J-1-S   ANO  6 


fit  loosely  over  the 
wooden  strip  "B" 
for  the  purpose  of 
preventing  the 
turning  of  the  coil. 
In  other  words, 
the  wooden  block 
"B"  forms  a  sort 
of  a  track  to  keep 
the  coil  from  mov- 
ing to  either  side. 
The  connectionsto 
this  coil  are  made 
with  flexible  leads 
which  will  allow  a 
back  -  and  -  forth 
movement  without  breaking  off  the 
leads.  The  dimensions  of  all  the  wooden 
pieces  are  given  in  Figure  3.  All  of  the 
coils  used  in  this  set  are  wound  upon 
fiber  forms  of  the  same  size  as  shown  in 
Figure  1.  To  construct  these  forms,- 
procure  some  sheet  fiber  1-16  of  an  inch 
thick.  This  fiber  sheet  should  be  per- 
fectly flat  and  not  warped  out  of  shape. 
Bakelite  will  also  answer  for  the  purpose, 
but  this  is  more  expensive.  From  this 
material,  cut  out  five  pieces  S  inches  in 
diameter  and  draw  a  circle  2  1-8  inches  in 
diameter  in  the  center  of  each,  and  divide 
the  outside  edge  into  13  equal  parts  and 
cut  a  slot  1-4  of  an  inch  wide  from  the 
outside  edge  to  the  edge  of  the  circle 
drawn  in  the  center. 

These  slots  will  be  1  7-16  inches  deep, 
which  will  give  ample  space  for  the  turns 
of  wire  which  are  to  be  wound  in  them. 
Coils  1,  2  and  6  are  wound  with  No.  22 
double  silk  covered  wire.  The  wire  is 
placed  in  one  of  the  slots,  leaving  an  end 
about  6  inches  long,  and  wound  over  two 
of  the  lugs;  then  through  the  slot  and 
over  the  next  two  lugs  on  the  other  side; 
then  through  a  slot,  over  the  next  two 
on  the  other  side,  etc. 

Using  a  Spring  Clasp 

COIL  No.  1  consists  of  30  turns  wound 
in  this  way,  and  at  each  fifth  turn  a 
small  loop  is  made  in  the  wire,  just  large 
enough  to  solder  a  wire  to,  when  the  set 
is  wired.  A  better  method  of  making  this 
connection  after  scraping  the  insulation 


20 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


COIL   5 


COILS  3  /\ 
AND  f 


off  from  these  loops 
is  by  using  a  small 
spring  clasp  which 
is  connected  to  a 
flexible  lead.  In 
this  way  the  num- 
ber of  turns  used 
may  be  varied 
easily  by  simply 
snapping  the  clasp 
on  the  desired  tap. 
Coils  No.  2  and  5 
are  wound  just  like 
Coil  No.  1,  the 
only  difference  be- 
ing that  each  of 
these  coils  must 
have  45  turns  of 
No.  22  wire. 

The  coil  No.  6, 
which  is  the  tick- 
ler, which  is  to 
slide  back  and 
forth,  is  also  wound 
in  the  same  way, 
but  has  only  20 
turns.  If  after  the 
set  is  assembled 
it    is    found    that 

oscillations  occur,  the  number  ot  turns 
on  this  coil  should  be  reduced.  The 
coils  No.  3  and  4  are  wound  on  one 
form.  They  are  wound  with  No.  26 
double  silk  covered  wire.  For  ease  of 
winding,  this  wire  should  be  first  wound 
on  two  spools.  Place  the  ends  together 
in  one  of  the  slots  and  wind  with  the  two 
strands  of  wire,  instead  of  the  single 
strand  as  in  the  other  coils.  Here  the 
method  of  winding  changes  slightly. 

Instead  of  winding  over  two  teeth  or 
lugs  as  before,  wind  over  only  one,  pass 
through  the  slot  and  over  the  other  lug 
on  the  other  side,  etc.  There  should  be 
22  turns  of  this  double  winding;  that  is, 
22  turns  of  each.  After  all  the  winding 
is  completed,  there  will  be  five  forms  and 
six  coils.  The  coil  1  is  the  aerial  induc- 
tance. Coils  2  and  5  are  the  secondary 
coils,  coils  3  and  4  are  the  plate  and  neu- 
tralizing coils,  and  coil  6  is  the  tickler. 

In  assembling  the  set,  coils  1  and  2  are 
mounted  on  wooden  blocks  as  shown  at 
"A,"  Figure  3.     These  are  made  adjust- 


WOODEN    DOWEL  PIN 


COIL  G 


PANEL 


'/¥'     SQUARE 
[HARO       WOOD 


•'  3" 


FIGURE     3 
SHOWING      METHOD   OF   MOUNTING 


COILS     3-M--5AND  6 


able  by  means  of  the  slots  in  the  blocks 
and  should  be  placed  about  1-2  inch  apart 
and  afterward  adjusted  until  the  best 
position  is  found,  where  they  are  fastened 
securely  and  left  in  this  position.  Coils 
3  and  4,  5  and  6  are  mounted  at  least  six 
inches  from  1  and  2,  and  at  right  angles 
to  them  as  shown  in  Figure  4.  By  mount- 
ing coils  3,  4,  5  and  6  back  away  from  the 
panel,  all  chance  of  body  capacity  inter- 
ference will  be  eliminated.  It  is  just  as 
easy  to  mount  them  in  this  position  as 
any  other,  as  it  will  require  only  a  longer 
wooden  rod  to  accomplish  this. 

Mounting  the  Parts 

r  I  ''HE  parts  should  be  mounted  about 
*-  as  shown  in  Figure  4.  This  arrange- 
ment may  be  varied  somewhat,  providing 
the  condensers  and  coils  are  not  placed 
too  close  together.  In  connecting  up  the 
various  coils,  one  must  be  careful  to  see 
that  the  outside  terminal  of  coil  No.  1 
is  connected  to  the  aerial  and  that  the 
ground  connection  is  made  to  one  of  the 


taps,  or  to  the  in- 
side terminal 
(whichever  ar- 
rangement gives 
the  best  results). 
The  outside  term- 
inals of  the  coils  2 
and  5  must  be 
connected  to  their 
respective  grids 
and  the  outside 
terminal  of  the 
plate  coil  is  con- 
nected to  the  plate 
of  the  first  tube. 
The  inside  ter- 
minal of  the  plate 
coil  must  be  con- 
nected to  the  out- 
side terminal  of 
the  neutralizing 
coil  as  shown.  A 
reversal  of  this 
connection  would 
ruin  the  neutral- 
izing effect  of  the 
coil.  The  bottom 
or  inside  terminal 
of  the  neutralizing 
coil  is  connected  through  the  neutraliz- 
ing condenser  to  the  grid  of  the  first 
tube.  This  neutralizing  condenser  should 
be  the  smallest  variable  condenser  which 
can  be  obtained. 

One  which  has  only  two  plates  will  best 
serve  the  purpose. 

There  are  many  of  these  midget  con- 
densers on  the  market  which  are  sold  for 
this  purpose,  but  if  such  cannot  be  ob- 
tained, the  ordinary  method  of  using  bus 
bar  wire  with  spaghetti  insulation,  such 
as  is  employed  in  the  neutrodyne  circuit, 
may  be  used.  It  will  be  found,  however, 
that  considerably  more  capacity  will  be 
required  than  that  used  in  the  neutrodyne 
circuit.  This  part  of  the  set  will  be  more 
or  less  experimental,  until  the  proper 
value  is  found.  The  correct  capacity  at 
this  point  is  the  most  important  part  of 
the  receiver. 

The  parts  required  for  the  construction 
of  this  receiver  are  as  follows: 

Six   coils   as   described,    two    23    plate 
(Turn  to  page  49) 


iri 


n\-a° 


fT\\ huh/  \    .ocas" 

r      W    (HUM  ^w,  II 


f\FT 


Fig.2 
(Schematic  Circuit) 


Foic 

leio 


A+&- 
-A- 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour  21 


An  IDEAL  Set  in  Practical  Form 


Fig.  1.     Rear  panel  view  of  set  described  by  Mr.  Silver.     All  apparatus  is  mounted  on  the  panel. 
there  being  no  need  for  a  baseboard. 


Fig.  Z.     Front  view  of  the  completed  set,  showing  controls 

A  Four-Tube,  Neutralized  Radio  Frequency  Receiver; 
Stable  Hookup  Gives  High  Efficiency  Over  Entire  Range 
by  Using  Regenerative  Detector  and  Usual  Amplifier 


THEORETICALLY,  a  broadcasting 
receiver  consisting  of  one  or  more 
stages  of  regenerative  radio  fre- 
quency amplification,  preceding  a  vacuum 
tube  detector  circuit  which  would  also 
be  regenerative  and  which  would  be  fol- 
lowed by  one  or  two  stages  of  audio 
amplification,  would  be  just  about  ideal 
from  the  standpoint  of  the  average  radio 
fan  who  is  interested  in  results,  low  cost 
and  general  simplicity. 

As  far  back  as  several  years  ago,  this 
combination  was  realized  to  be  highly 
desirable,  and  a  number  of  text-books 
can  be  found  in  which  some  such  layout 
was  given,  generally  followed  by  a  nota- 
tion to  the  effect  that  while  the  system 
had  wonderful  possibilities,  it  would 
indeed  be  a  good  man  who  could  get  it 
to  function  really  satisfactorily.  This, 
it  must  be  remembered,  was  several  years 
ago  when  the  neutrodyne  was  but  a 
dream  and  low-capacity,  low-impedance 
tubes  were  practically  unheard  of. 

Before  going  into  the  details  of  a  prac- 
tical form  of  this  circuit,  it  might  be  well 
to  consider  the  neutrodyne  system  and 
the  allied  systems  of  tuned  radio  fre- 
quency amplification.  Essentially  a  neu- 
trodyne is  nothing  more  than  a  tuned 
radio  frequency  amplifier,  the  neutrodyne 
principle  being  merely  an  arrangement 
whereby  an  excessive  amount  of  energy 
due  to  regeneration,  which  might  cause 
oscillation,  is  so  balanced  out  that  oscil- 


By  McMURDO  SILVER 


Assoc,  I.  R.  E. 


lation  cannot  take  place.  Actually,  a 
neutrodyne  is  highly  regenerative  on  the 
shortest  wavelengths  at  which  it  will 
operate,  but  it  is  so  balanced  that  oscilla- 
tion cannot  take  place  upon  the  shortest 
wave  to  be  received — say  200  meters. 
When  the  receiver  is  tuned  to  its  highest 
wave,  — 550  meters, — the  amount  of 
regeneration  present  will  have  fallen  off, 
with  the  result  that  the  selectivity  and 
sensitivity  are  very  much  poorer  than  on 
the  lower  waves.  This  is  the  basic  fault 
of  tuned  radio  frequency  amplifying 
systems — if  they  are  to  be  simple  in 
operation  and  thoroughly  stable,  their 
efficiency  will  not  remain  anywhere  near 
constant  over  their  full  wavelength  range. 
Tuned  radio  amplifiers  not  employing 
neutralization  must  have  losses  intro- 
duced into  their  circuits  if  they  are  to  be 
kept  stable,  another  common  stabilizing 
method  being  to  so  arrange  the  coupling 
coils  that  energy,  fed  through  on  the  low 
waves,  will  be  insufficient  to  cause  oscil- 
lation. Due  to  the  fall-off  in  regeneration 
with  an  increase  in  wavelength,  most  such 
sets  are  poor  performers  on  t  he  high  waves. 

Stability  a  Feature 

ONE  of  the  advantages  of  the  neutro- 
dyne is  its  stability;  hence  it  is  pos- 
sible to   realize,   by   using  a  neutralized 


R.  F.  amplifier,  our  ideal  receiver,  for  we 
can  combine  a  regenerative  detector  cir- 
cuit in  conjunction  with  a  neutrodyne 
amplifier  that  will  do  much  to  even  up 
the  efficiency  of  the  set  over  its  entire 
range.  If  such  a  combination  is  carefully 
designed,  the  losses  in  amplification  in 
the  R.  F.  section  on  the  high  waves  may 
be  compensated  for  appreciably  by  the 
controllable  regeneration  in  the  detector 
circuit;  yet  the  fact  that  the  detector  may 
be  oscillating  will  not  unbalance  the  sys- 
tem. 

Before  considering  the  design  of  a 
circuit  which  renders  this  combination 
possible  and  entirely  practical,  we  must 
realize  that  in  this  design  we  have  accom- 
plished two  very  important  operating 
improvements,  almost  at  one  stroke. 
The  first  is  the  eliminating  of  radiation 
from  the  receiver  due  to  the  transmission 
of  energy  from  the  detector  circuit,  when 
it  is  oscillating,  to  the  antenna  system. 
This  is  prevented  by  the  neutralized  or 
balanced  condition  of  the  R.  F.  amplifier, 
which  prevents  the  passage  of  energy 
from  its  plate  circuit  back  through  to  its 
grid  circuit. 

This  permits  the  detector  to  be  oper- 
ated in  an  oscillating  condition  with  no 
fear  of  the  receiver  radiating  and  dis- 
turbing the  neighbors.  Here,  then,  is 
the  second  important  operating  improve- 
ment— the  detector  may  be  made  to 
oscillate    and    stations    located    with    but 


22 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


one  dial,  merely  by  turning  the  detector 
tuning  condenser  until  the  desired  whistle 
is  heard,  as  on  a  regenerative  set.  The 
R.  F.  amplifier  is  then  adjusted  until  the 
whistle  is  loudest,  and  the  detector 
stopped  from  oscillating  by  reducing  its 
tickler  coupling.  Actuall}-  three  or  more 
controls  are  used  on  such  system,  of 
which  only  one  need  be  used  to  find 
unknown  stations. 

In  practically  constructing  such  a 
system,  there  are  several  ends  to  be 
achieved,  and  upon  them  will  depend  the 
means  employed.  The  first  point  is  that 
the  receiver  must  go  down  to  the  noise 
level  and  bring  in  with  loud-speaker  vol- 
ume any  signals  heard  with  sufficiently 
greater  intensity  than  the  ever-present 
atmospheric  noise  to  be  distinguished 
from  it  satisfactorily.  Then,  the  receiver 
must  be  selective  enough  to  cut  through 
the  entire  group  of  local  stations  in  cen- 
ters such  as  Chicago  or  New  York,  and 
bring  in  dependably  stations  all  over  the 
country.  The  set  must  be  simple  to 
construct  and  operate,  the  upkeep  cost 
must  be  low,  a  minimum  numbers  of 
tubes  should  be  used,  and  all  parts  should 
be  procurable  on  the  open  market. 

Layout  Insures  Efficiency 

T^HE  practical  answer  to  these  and 
-*-  many  other  more  involved  require- 
ments, both  from  the  standpoint  of 
theoretical  as  well  as  practical  efficiency, 
is  illustrated  in  Figures  1  and  2.  Figure 
2  is  a  front  view,  showing  all  controls 
mounted  on  a  standard  7  x  24  panel.  The 
left  dial  is  the  antenna,  or  R.  F.  stage 
condenser,  the  next  the  detector  con- 
denser, and  the  next  the  tickler.  To  the 
right  is  the  rheostat  knob  and  the  battery 
binding  posts.  The  lay-out  is  not  only 
pleasing  to  the  eye,  but  makes  for  the 
greatest  possible  efficiency. 

Figure  1  is  a  rear  view  of  the  set.  At 
the  right  is  the  antenna  inductance, 
mounted  on  the  back  of  its  tuning  con- 
denser. Next  is  the  R.  F.  tube  socket, 
with  the  neutralizing  condenser  mounted 
directly  on  its  grid  post.  To  its  left  is 
the  detector  condenser,  then  the  detector 


socket  with  its  grid-condenser  and  leak. 
Next  is  about  the  most  important  piece 
of  equipment  in  the  set,  the  R.  F.  coupler, 
with  its  adjustable  tickler.  Upon  the 
design  and  construction  of  this  coupler 
depends  the  stability  of  the  outfit,  for 
even  a  very  slight  variation  in  the  size  or 
location  of  the  primary  coil,  placed  inside 
the  bottom  end  of  the  stator  coil,  would 
throw  the  results  of  the  whole  receiver 
off.  At  the  left  end  of  the  panel  are  the 
two  audio  tube  sockets,  placed  over  the 
audio  transformers,  and  behind  the  rheo- 
stat controlling  all  four  tubes.  On  the 
left  end  of  the  panel  are  the  battery 
binding  posts,  on-off  switch  and  jacks. 
No  sub-base  is  used,  all  parts  mounting 
directly  upon  the  panel. 

The  receiver  illustrated  consists  of  one 
stage  of  tuned,  neutralized  R.  F.  ampli- 
fication, a  regenerative  second  detector 
and  two  stages  of  distortionless  audio 
amplification.  The  condensers  used  are 
of  the  grounded  rotor,  low-loss  type,  and 
aside  from  preventing  hand-capacity,  are 
extremely  efficient.  The  antenna  coil 
and  R.  F.  coupler  are  especially  designed 
for  the  circuit,  and  employ  self-supporting 
windings,  rendered  rigid  by  a  special 
treating  compound.  As  a  matter  of  fact, 
tests  by  Armour  of  Chicago  indicated  that 
these  coils  so  treated  have  less  resistance 
on  a  dry  day  than  untreated  coils  sup- 
ported with  two  strips  of  adhesive  tape, 
while  for  a  damp  day  the  doped  coil 
showed  26  ohms  less  resistance  than  the 
undoped  coils.  This  figured  out  to  be 
about  500  per  cent  greater  resistance  for 
the  untreated  winding.  These  tests 
indicate  that  the  high  efficiency  claimed 
for  the  untreated  coils,  with  which  the 
market  is  now  flooded,  is  purely  mythical, 
but  much  depends  upon  the  use  of  a  good 
dope,  such  as  is  not  available  on  the  open 
market. 

Results  Obtained 

'"pHE  test  of  any  design  is  what  it  will 
•*•  do,  and  merely  figuring  out  an  ideal 
receiver  on  paper  is  far  from  building  it, 
and  testing  it  under  a  variety  of  condi- 
tions. 


A  large  number  of  these  sets  have  been 
built  and  used  in  and  around  Chicago, 
with  the  results  obtained  by  one  builder 
typical  of  those  obtained  by  the  others, 
with  due  allowance  for  location  and  condi- 
tions. A  physician  in  Wilmette  built  the 
set  in  a  period  of  three  hours,  hooked  it 
up  at  four  in  the  afternoon,  and  before 
eight  o'clock  had  gotten  27  stations  on 
his  loud  speaker,  ranging  from  Toronto 
to  Fort  Worth,  in  daylight!  In  a  week 
he  logged  over  100  stations,  never  once 
resorting  to  head-phones. 

The  material  required  to  build  the 
receiver  is  given  in  the  list  below,  with 
an  accessory  list  farther  along.  It  is 
strongly  recommended  that  the  builder 
adhere  strictly  to  this  list.  If,  however, 
the  experimenter  desires  to  deviate,  he 
should  only  do  so  where  his  knowledge 
is  sufficient  to  effect  the  necessary  design 
changes  attendant  upon  the  use  of  mater- 
ial other  than  those  specified. 


2  Low  loss  condensers  .0005. 

3  4-inch  Moulded  dials — tapered  knobs. 
1  ayi  Ohm  rheostat. 

6  Insulated  top  binding  posts 

1  2  Spring  jack. 

1  1  Spring  jack. 

1  Low  loss  coupler. 

1  Low  loss  antenna  coil. 

4  Panel  mounting  sockets. 


2  31^:1  Audio  transformers. 
1  On-Off  switch. 


I  .00025  Mica  Condenser  with  leak  clips. 

1  .002  Mica  Condenser. 

1  .0075  Mica  Condenser 

1  2  Meg  Grid  leak. 

1  7i24x3-16"  panel. 
Bus-bar,  spaghetti,  screws,  nuts,  solder,  lugs,  etc. 
TOOLS    REQUIRED:     Screw    driver,    pliers,    soldering 
iron,  hand  drill  with  drills,  and  countersink. 


If  a  plain  panel  is  used,  it  should  be 
drilled  in  accordance  with  the  layout 
given,  and  the  necessary  holes  counter- 
sunk. If  desired,  it  may  be  given  a 
grained  finish  by  rubbing  in  one  direction 
only  with  sand-paper  and  oil.  Indicating 
marks  for  the  dials  may  be  scratched 
with  a  scriber  and  filled  in  with  Chinese 
white. 

The  antenna  coil  should  be  attached  to 
one  of  the  variable  condensers.  Care 
should  be  taken  to  see  that  the  loop,  or 
tap  on  the  coil  comes  near  the  right-hand 
end  of  the  condenser,  when  viewed  from 
the  rear,  with  the  stator  or  fixed  plate 
(Tvrn  to  Page  56  ) 


a»9oO- 


Fig.  3.  Layout  of  apparatus  in  set  described  by  Mr.  Silver.     Study  of  this  figure  and  No.  J  should  enable  any  RADIO  ACE 

reader  to  make  such  a  set. 


RADIO  AGE  for  June,   1925 


The  Magazine  of  the  Hoi 


Proper  SOLDERING  Insures 

Efficient  Circuit  Operation 


Pictorial  Tips 
•  for  the  Set-Builder 
on  This  Essential 
Radio  Topic 

GOOD  connections  mean  good  contacts 
and  perfect  circuits.  These  the  set- 
builder  must  have  if  he  is  to  be  repaid  for  his 
efforts  with  good  reception  and  pure  tonal 
quality.  The  first  thing  to  be  done  in  setting 
out  on  a  soldering  job  is  to  clean  the 
soldering  iron  thoroughly,  as  shown  in  the 
photograph  at  the  left.  Use  a  file  for  this 
preliminary  job,  and  see  that  all  grit  and 
other  impedimenta  are  removed  before 
actually  turning  to  the  solder,  This  means 
the  solder  will  be  absolutely  clean. 


PROCEDURE  Number  Two  in  doing 
good  soldering  is  to  clean  the  connec- 
tions to  be  soldered  with  the  same  care  that 
was  given  the  iron  itself.  The  first  photo- 
graph at  the  right  illustrates  this  method. 
When  both  iron  and  wire  are  clean,  good 
contact  is  assured.  Next,  apply  the  solder- 
ing flux,  as  'shown  in  the  photo  to  the  left. 
Be  sparing  in  the  application  of  the  flux, 
tor  many  poor  connections  are  often 
caused  by  the  use  of -the  flux  in  excessive 
quantities.  Do  it  right  the  first  time  and 
you  won't  be  taking  your  set  apart  time  and 
again  after  it  has  been  put  into  operation. 


A  T  the  right  is  a  good  idea  of  how  to 
■*  *■  apply  the  solder  to  the  joint.  [Note  that 
only  a  small  amount  of  the  solder  is  neces- 
sary on  the  tip  of  the  iron.  Rub  it  over  the 
joint  to  be  soldered  until  it  runs  freely, 
and  then  let  the  joint  cool.  Some  radio 
experts  have  said  that  the  best  test  of  a 
soldering  job  is  to  drop  your  wired  set  on 
the  floor,  and  if  the  wires  stay  intact,  the 
soldering  is  satisfactory!  However,  this 
method  often  proves  disastrous  to  the  rest 
of  the  set,  so  be  on  the  safe  side  by  testing 
the  soldered  joints  with  your  hands.  And 
once  you  are  sure  the  job  is  satisfactory, 
leave  it  alone. 

I Eadel  and  Herbert  Photos.) 


24  RADIO  AGE  for  June,  1925 


Wkat  tke 
roadcasters 
are  Doing 


What  the  Broadcasters  are  Doing 

Will 


WJZ  Broadcasts  for  the  Tired 
Business  Man 

T^OR  once  the  male  radio  fans  have 
*-  come  into  their  own.  Women  listen- 
ers, for  whom  special  "Women's  Hour" 
programs  have  been  instituted  and 
featured  since  radio  began,  now  have  no 
consideration  at  the  hands  of  station 
WJZ,  New  York  City.  The  long-suffer- 
ing, bill-paying  husbands  are  being  given 
something  for  nothing;  and  the  some- 
thing is  designed  for  their  ears  and  theirs 
alone. 

"For  T.  B.  M's.  Only."  So  read  the 
WJZ  program  between  8:40  and  10 
o'clock  on  March  9.  What  a  T.  B.  M. 
is,  every  follower  of  the  Great  White 
Way  knows;  he  is  the  gold-digger's  de- 
light, the  Great  Mogul  to  whom  all 
Broadway  bows  low  the  while  they  re- 
lieve him  of  vast  fortunes;  viz.,  the 
"Tired  Business  Man."  And  WJZ  has 
planned  to  bring  him  surcease  from  his 
suffering,  to  relieve  the  chronic  ennui 
of  the  peculiar  species  without  reliev- 
ing his  pocketbook.  Truly  radio  is  a 
Marvel! 

Enter  the  "Chics" 

The  Two  Maries  crooned  the  kind  of 
blues  that  only  men  appreciate;  George 
Laval  Chesterton  rendered  an  episode 
entitled  "Wa-a-a-ah!"  which  was  directed 
straight  to  the  sorely-tried  hearts  of  the 
T.  B.  M's.;  the  World's  Worst  Radio 
Speaker  unburdened  his  soul  to  an  audi- 
ence  which  shouldn't  have  contained 
any  women!;  Fay  Marbe,  Broadway's 
Peppiest  Play-Girl,  put  across  a  radio 
act  that  made  WJZ  request  a  special 
police  guard  at  the  studio  to  fight  off 
the  admiring  "studio-door  Johnnies;" 
Sam  Hermann,  with  Muriel  Pavellock, 
arranged  an  act  that  brings  $5.50  top 
anywhere  in  civilization;  John  C.  Cutting, 
the  Baldest  Man  in  Three  Continents, 
described  the  harrowing  night-life  which 
made  his  hair  fall  out;  and  Norman  E. 
Brokenshire  mounted  his  ukelele  and 
sang  a  song  that  made  the  well-known 
"Parley- Vous"  fade  into  the  background 
of    respectibility. 

"For  T.  B.  M.'s  Only!"  WJZ  has 
given  full  warning  to  all  feminine  listeners 
to  remain  away  from  the  loudspeakers 
and  ear-phones  on  these  nights;  and  for 
the  sake  of  peace  in  the  family  it  advises 
all  married  men  to  keep  their  wives  away 
from  the  receiving  set.  And  above  all, 
WJZ  earnestly  entreats  all  men  not  to 
tell  their  feminine  contingents  what 
they  are  laughing  at — if  they  should 
stop  laughing  long  enough  to  be  able 
to  tell! 


Above  is  Herbert  Sidney  Mintz,  musical  director 
and  announcer  of  the  new  Wrigley-Hermann- 
Thompson  radio  station,  WHT,  which  has  opened 
towers  in  Deerfield,  111.,  and  studios  in  Chicago. 
Mintz  is  an  old  KYW  artist. 


ALBERT  HAY  MALOTTE,  the  con- 
cert organist  at  McVicker's  Theatre, 
Chicago,  has  firmly  established  him- 
self as  one  of  Chicago's  favorite  radio 
stars.  Mr.  Marlotte's  supreme  artistry 
as  well  as  his  natural  faculty  for  picking 
selections  and  arranging  programs,  has, 
in  the  short  period  of  time  he  has  been 
on  the  air,  made  him  a  midnight  feature 
worth  staying  up  late  to  hear.  His  con- 
certs start  every  Wednesday  and  Friday 
night  at  fifteen  minutes  after  midnight 
at    KYW. 

Malotte  has  had  a  wide  and  varied 
experience,  having  been  a  professional 
aviator  on  the  Pacific  Coast  several  years 
ago.  After  flying  for  some  time  he  went 
to  Alaska  to  fill  concert  engagements 
and  in  a  country  where  almost  every 
man  is  a  dead  shot,  he  won  the  first  prize 
in  a  rifle  contest.  He  has  been  a  big 
game  hunter  in  the  Rockies  and  proudly 
displays  an  enormous  mountain  lion 
skin  whose  owner  fell  under  his  unerring 
aim. 


Albert  Hay  Malotte,  concert  organist 
at  McVicker's  Theater,  Chicago,  who  is 
gaining  friends  among  the  Middle  West- 
ern radio  fans  through  his  midnight 
broadcasts  from  KYW. 


Some  Sidelights  on  Radio  and 
the  Stage 

By  Wilson  J.  Wetherbee,  Director, 
Westinghouse  KYW 

OF  LATE  producers  of  the  drama  and 
its  melodious  kin,  the  musical 
comedy,  have  seen  spectres  stalking  in 
the  rapidly  increasing  popularity  of 
radio.  Evidently  they  are  convinced 
that  broadcasting  is  here  to  stay  and 
that  no  amount  of  scoffing  can  stem  its 
advance.  These  folk  of  the  theater 
appear  disconsolate  when  they  should 
be  rejoicing  over  the  discovery  of  a  new 
medium  for  popularizing  the  American 
stage. 

Just  why  the  theatrical  world  has 
levelled  its  guns  on  radio  is  a  difficult 
question  to  answer.  There  is  no  one 
kind  of  diversion  which  will  satisfy  all 
of  the  desires  of  the  public.  Good  show- 
manship is  builded  upon  no  one  factor 
so  much  as  experience,  but  with  the 
coming  of  radio,  the  theatrical  producers 
have  apparently  been  blinded  to  the 
words  of  wisdom  which  appear  in  every 
primer   devoted    to   theatricals. 

For  the  moment  let  us  grant  that 
radio  broadcasting  will  divert  the  public 
from  the  box  office.  Let  us  say  that  the 
amusement  seekers  turn  to  a  quiet 
evening  at  home  and  a  receiving  set  for 
recreation. 

The  Reaction  to  Radio 

Now  that  we  have  the  former  theater- 
goer safely  at  home  with  his  new  radio, 
let  us  also  study  his  reaction.  He  hears 
a  clever  monologue,  enjoys  a  medley 
played  by  a  deft  fingered  pianist,  dis- 
covers that  his  feet  want  to  dance  to  a 
tune  being  played  by  an  orchestra  and 
learns  also  that  he  would  like  to  see  the 
possessor  of  the  sweet  voice  which 
thrilled  him  with  a  love  ballad.  He 
listens  attentively  as  the  announcer  gives 
the  name  of  the  artist.  Perhaps  the 
performer  is  an  amateur  whose  only 
public  appearance  is  over  the  radio. 
Again  he  may  recognize  the  name  as 
that  belonging  to  a  famous  star  who  is 
appearing  in  some  production  in  his 
own  city.  In  the  latter  case  the  chances 
are  ten  to  one  the  listener  will  buy  a  seat 
for  the  show  in  which  his  radio  favorite 
is    appearing. 

Perhaps  the  theater  manager  will 
scoff  at  this  assumption.  The  directors 
of  KYW  have  good  reason  to  believe 
that  their  assumption  is  true.  The 
broadcasting  of  "Abie's  Irish  Rose" 
brought  2,876  persons  to  the  box  office 
within  forty-eight  hours  after  the  pro- 
duction was  broadcast. 


RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doinz 


25 


C  California  is  Leading  the  Country  in  the 
Development  of  Efficient  Radio  Stations 

The  Broadcast  Favorites  of 
Southern  California 

Some  Notes  from  the  Sunny  Radioland 
By  RALPH  L.  POWER 


Up  at  KHJ  the  Lost  Angels  go  on  the 
air  at  midnight  Saturday  for  a  two  or 
three  hour  program  of  fun  and  frolic, 
similar  to  the  Hoot  Owl  program  up  in 
Portland.  Then,  again,  they  have  a 
Saturday  afternoon  frolic  that  is  becom- 
ing a  classic  in  radioland.  One  of  the  most 
popular   instrumentalists    from   this   sta- 


"Herb"     Rawlinson,     popular    movie 

Star,  seems  to  be  having  a  good  time 

showing  his  radio  listeners  how  to  solve 

that  intricate  cross-word  puzzle. 

WITH   its    six    500- watt    sets, 
and  one   1,500-watt    station, 
Southern    California    can   be 
tuned   in  'most  any  time  and  radio 
fans  from  the  East  and   Middle  Western 
states  are  picking  up  programs  from  the 
Pacific  Southwest    with    somewhat   more 
regularity  than  a  year  or  so  ago. 

"Herb"  Rawlinson,  veteran  film  player, 
has  given  speeches  and  bedtime  stories 
from  most  of  the  Los  Angeles  stations. 
In  fact,  he  acted  as  a  radio  announcer 
during  the  recent  radio  show  in  that  city. 
But  Rawlinson  can't  get  away  from 
rehearsal  habits.  In  the  picture  we  find 
him  trying  to  explain  a  cross-word  puzzle 
joke  to  radioland  with  the  use  of  a  dic- 
tionary. 

Over  at  KFSG  there  are  church  serv- 
ices on  the  air  day  and  night.  One  of  the 
most  interesting  is  the  Thursday  night 
water  baptismal,  at  which  nearly  a  hun- 
dred people  go  through  the  baptismal 
process.  The  musical  part  of  the  broad- 
cast includes  songs  by  the  Southern 
jubilee  singers  and  the  temple  silver 
band  music.  But  the  most  popular  enter- 
tainer from  this  Los  iVngeles  station  is 
Esther  Fricke  Greene,  who  presents  an 
hour's  program  of  organ  selections  three 
times  a  week. 


(McHenry  Photo,  Hollywood) 

Al    Wilson,  a  stunt  aviator  for  the  movies, 

thrills    the    radio    listeners    regidarly  from 

KFI,  Los  Angeles. 

tion — ^the  oldest  500  watter  in  Southern 
California — is  Jules  Lepske,  member  of 
the  famous  Philharmonic  Orchestra  and 
leader  of  the  Philharmonic  Quintet  which 
plays  from  KHJ  twice  a  week. 

Hollywood  now  has  two  stations — 
KXX  and  KFWB — at  which  a  goodly 
number  of  screen  stars  talk.  But  the 
radio  public  is  fairly  well  fed  up  with 
patter  and  demands  entertainment.  Herb 
Rawlinson,  by  the  way,  always  carries 
his  favorite  uke  along. 

So  the  Hollywood  stations  are  provid- 
ing a  good  deal  of  musical  entertain- 
ment. During  the  Summer  months  the 
Hollywood  Bowl,  a  civic  enterprise,  con- 
ducts a  series  of  ten  weeks'  open  air  con- 
certs and  as  a  forerunner  of  these  they 
are  now  providing  some  radio  concerts. 

Their  radio  pianist  is  Raymond  Mc- 
Feeters,  talented  young  composer,  who 
acts  as  concert  pianist  at  the  Bowl  and  as 
organist  at  one  of  the  local  churches. 

Little    Peggy    Lynne    recently   won    a 


gigantic  beauty  contest  prize  in  the 
metropolis  of  Southern  California  and  is 
a  prime  favorite  with  radio  fans. 

A  L  WILSON  has  just  finished  a  film. 
-£*-  "The  Cloud  Rider,"  and  he  often 
tells  his  radio  audience  about  his  stunts 
in  the  clouds  as  a  stunt  man  for  filmland. 

Tune  in  on  Southern  California  sta- 
tions and  hear  their  programs. 

If  you  tune  in  on  KFI  on  alternate 
Wednesday  nights  from  9  to  10,  Pacific 
Standard  time,  you  will  hear  the  Wampas 
program,  given  by  the  official  organiza- 
tion of  the  film  colony.  These  programs 
have  presented  Adolphe  Menjou,  Adolpha 
Menjou,  Trixie  Friganza,  Louise  Fazenda, 
Viola  Yorba,  Betty  BIythe,  Bert  Lytell, 
Marguerite  de  la  Motte,  John  Bowers. 
Fred  Stanton  and  hundreds  of  other 
screen  celebrities  who  entertain  by  song 
and  speech. 

Los  Angeles  stations  now  include  KFI, 
on  1,500  watts,  and  the  following  on  300: 
KHJ,  KFSG,  KNX  and  KFWB,  the  last 
two  being  in  Hollywood.  KFON  at 
Long  Beach  is  also  a  500  watter. 


(Photo  bF  Witzel; 


Raymond    McFeeters,    the    wistful     youth 

shown    above,  is  a  regular   concert  pianist 

from  KI\'X,   Hollywood,    where   the  movie 

stars  come  from. 


26  RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doin<? 


Photo  by  Bloom,  Chicago' 


"STAY    A     WHILE     WITH     W-Q-J." 

In  this  intimate  way,  "Jerry"  Sullivan,  the  unusual  announcei 
and  entertainer  at  WQJ,  the  Calumet-Rainbo  Gardens  Station  at 
Chicago,  begins  his  popular  jazz  programs  every  evening  at  10  o'clock. 
Jerry  has  a  style  of  announcing  all  his  own,  and  needless  to  say,  it 
has  won  him  hosts  of  admirers.  He  was  one  of  the  first  devotees  of 
the  "crooning"  method  of  broadcasting.  He  is  also  a  pianist  of  un- 
usual ability. 


RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doing  27 


Trials  and  Triumphs  of  an  Announcer 


Catering 

to  the  Whims 

of  a  Fickle 

Audience 

Is  No 

Child  s  Play 

at  KDKA 


ANNOUNCING  radio  programs 
might  be  called  the  world's  most 
-  recent  profession,  because  an- 
nouncers for  broadcasting  stations  were 
introduced  first  about  four  years  ago 
when  KDKA,  the  world's  pioneer  station 
of  the  Westinghouse  Company  at  East 
Pittsburgh,   Pa.,  was  started. 

H.  W.  Arlin,  the  world's  pioneer  radio 
announcer,  made  his  debut  early  in 
1921  and  has  been  continuously  "on  the 
air"  since.  Thus  his  long  service  entitles 
him  to  the  honors  of  being  the  veteran 
of  radio  announcers. 

Mr.  Arlin's  studio  experiences  have 
been  many  and  varied.  Life  as  a  radio 
announcer  is  not  a  drab  affair,  as  there 
is  a  necessity  of  being  continually  on  the 
"qui  vive." 

In  the  following  interview  Mr.  Arlin 
tells  of  some  of  his  studio  experiences 
and  some  interesting  contacts  with  his 
radio  public. 

He  Never  Tires 

I"  AM  often  asked  the  question,  'Do 
-*-  you  become  tired  of  announcing?' 
or  'Does  radio  work  become  monoton- 
ous?' My  answers  to  such  questions 
are  always  in  the  negative,  thanks  to 
an  ever-curious  and  an  assisting  public. 
By  such  an  answer,  I  mean  that  any 
motonony  which  might  otherwise  tend 
to  creep  into  the  almost  continual  execu- 
tion of  programs  is  quickly  dispelled 
by  a  multitude  of  extraneous  duties 
with  which  an  announcer  is  confronted. 
"Probably  one  of  the  most  interesting 
phases  of  studio  work  comes  through 
contact  with  the  public,  not  entirely  by 
personal  association,  but  also  through 
the  telephone  and  telegraph.  No  work 
can  become  monotonous  or  tiresome 
where  the  public  is  involved.  On  the 
contrary,  I  have  found  that  a  study  of 
the  whims  and  fancies  of  the  public 
has  been  an  exceedingly  interesting  one. 


H.  W.  Arlin,  "World's  Pioneer  Announcer" 

Paraphrasing  the  famous  expression  of 
Abraham  Lincoln,  'You  can  please  some 
of  the  people  all  of  the  time,  and  all  of  the 
people  some  of  the  time;  but  you  can't 
please  all  of  the  people  all  of  the  time.' 
Not  radio,  at  any  extent.  This  state- 
ment could  be  applied  to  the  view  of  the 
public  on  any  one  phase  of  radio  enter- 
tainment such  as  music  or  sports.  When 
applied  to  all  of  the  phases  of  radio,  it 
becomes  many  more  times  effective. 
What  one  person  likes,  another  dislikes, 
and  what  one  person  condemns,  another 
approves;  so  an  announcer  is  almost 
justified  in  concluding  that  a  'fifty-fifty 
break'  with  the  listening  public  is  fair 
enough.  However,  100  per  cent  satis- 
faction is  always  the  goal. 

"In  telling  of  the  announcer's  contact 
with  the  public  we  may  take  into  con- 
sideration only  one  phase  of  this  contact; 
that  of  telephone  conversations.  The 
nature  of  the  telephone  messages  re- 
ceived, together  with  the  conversations 
that  follow,  tend  to  create  in  one  a  desire 
for  the  study  of  people.  The  thoughts 
and  ideas  which  prompt  these  many 
calls  are  perhaps  innumerable;  perhaps 
some  one  conceives  an  idea  by  which 
radio  can  be  of  aid  to  him  in  his  own 
personal  advancement  or  the  advance- 
ment of  some  pet  theory,  or  possibly 
some  one  desires  some  information  which 
may  vary  from  that  of  a  query  regarding 
what  is  the  proper  food  to  give  a  sick 
baby  to  that  of  certain  details  regarding 
a  program  to  be  broadcast  several  weeks 
hence. 

Some  of  the  Questions 

\  FEW  of  the  seemingly  endless 
-'-*-  number  of  such  questions  and  re- 
quests may  be  of  interest.  A  confiding 
interest  in  our  listeners,  (this  same  pub- 
lic) will  necessitate  the  omission  of  the 
names  of  any  personalities  involved  in 
the  following: 


H.  W.  Arlin,  the 
World' s  Pioneer 
Announcer,  Has 
Never  Tired  of 
the  Rad  io  Game  ; 
Here  are  Some 
of  His  Reasons 


"One  of  our  good  Canadian  friends 
recently  called  to  tell  us  about  a  circular 
parking  station  he  had  invented  for  auto- 
mobiles which  would  handle  two  hundred 
cars  and  which  could  be  operated  by 
one  man.  -  Appreciating  the  need  for 
better  parking  service  and  predicting 
great  success  for  his  venture,  he  requested 
that  we  advise  the  radio  public  of  his 
invention  with  full  details  as  to  where 
to  purchase  these  stations. 

"A  lady  calls  us  and  requests  that  we 
announce  that  she  has  just  left  a  package 
of  pajamas  on  the  street  car  and  would 
like  to  have  the  service  of  the  radio  in 
recovering  them.  After  being  informed 
that  we  never  make  local  announcements 
except  in  cases  of  robberies,  kidnapping, 
lost  persons  and  such  emergencies,  she 
replies,  'Well,  this  is  an  emergency  case, 
because  it  is  the  only  package  I  had.' 

"An  elderly  lady,' apparently  a  student 
of  nature,  calls  and  gives  us  the  following 
important  news  item:  'Will  you  please 
announce  that  there  is  about  four  inches 
of  snow  in  my  back  yard  and  that  I 
have  just  s#en  two  cardinal  red  birds?' 
Of  course,  a  very  unusual  sight  for  this 
time  of  the  year. 

"No  sooner  is  the  telephone  receiver 
on  the  hook  than  the  bell  again  rings  and 
an  innocent  feminine  voice  pops  the 
following  impression:  'I  just  heard  you 
announce  that  you  had  received  a  tele- 
gram from  New  York  commenting  on  the 
program.  I  would  like  to  know  if  you 
are  also  broadcasting  to  Ohio  tonight, 
as  I  would  like  to  request  a  number  for 
some  friends  out  there  who  do  not  have 
the  advantages  of  a  radio.' 

"It  has  also  been  brought  very  forcibly 
to  my  attention  that  radio  has  made  a 
greater  impression  upon  the  public  than 
has  music.  Of  the  many  proofs  of  this 
statement,  I  might  cite  an  occasion  on 
which  a  program  was  being  presented  by 
the  great  Fritz  Kreisler.        (To  page  62) 


28 


RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doing, 


Radio  Reveals  a  New 
Civilization 

Unpublished  Details  of  a  Newly  Discovered 

Race,  Twenty-Two  Centuries  Old,  Given  For 

First  Time  From  KOA,  at  Denver. 

By  FRANK  J.  McENI'RY 


WIDELY  scattered  re- 
mains of  a  vast,  al- 
together unknown  civiliza- 
tion which  for  twenty-two 
centuries  has  been  buried 
under  three  to  ten  feet  of 
waste  and  crumbled  rock, 
are  just  being  opened  in 
southwestern  United  States. 
They  definitely  establish, 
archeologists  declare,  that 
Colorado's  Cliff  Dwellers 
were  not  the  oldest  pre- 
historic race  to  flourish  on 
the  North  American  con- 
tinent. 

How  long  this  newly  dis- 
covered civilization  thrived, 
from  whence  it  came  and 
how  and  when  it  was  wiped 
away  are  facts  which  ex- 
cavators from  the  Colorado 
State  museum  are  now 
endeavoring   to   determine. 

In  the  meantime,  however, 
scientists  have  been  dumb- 
founded at  finding  a  lost 
city  of  pithouses  extending 
along  the  tops  of  a  strag- 
glingseriesof  mesasinsouth- 
western  Colorado,  which 
swing  from  a  point  near  the 
Colorado-Utah  border  in 
the  Paradox  valley  to  Pa- 
gosa  Springs,  Colo.,  and 
thence  south,  well  into  New 
Mexico. 

Unpublished  details  of 
this  astounding  settlement, 
a  comprehensive  civiliza- 
tion in  itself  and  the  largest 
yet  determined  of  prehis- 
toric America,  were  pre- 
sented by  radio  on  April  8  I 
over  KOA,  the  General 
Electric  station  at  Denver,  by  Joseph 
Emerson  Smith,  member  of  a  recent 
archeological  expedition  into  this  region 
by  the  Colorado  museum.  This  unique 
program,  which  was  being  sponsored  by 
the  Denver  Tourist  bureau,  was  given  as 
part  of  a  studio  presentation  beginning 
at  8:10  p.  m. 

1000  Years  Before  Cliff  Dwellings 
r  I  "'HIS  lost  city  comprised  scores  of 
*-  separate  and  distinct  units,  which 
for  the  sake  of  defense  advantages  were 
confined  to  the  tops  of  mesas  or  table 
lands,  high  above  the  valleys  below. 
Five  hundred  pithouses  in  one  group 
alone  have  just  been  mapped  in  what  is 
now  known  as  the  Chimney  Rock-Piedra 


Above  are  the  ruins  of  a  prehistoric  watch  tower  in  Colorado,  which  once  commanded  a 
valley  1,600  feet  below.  The  insert  shows  the  skeleton  of  a  prehistoric  woman  and 
remarkably  symmetrical  pieces  of  gray  ware,  which  were  uncovered  in  a  nearby  pit-house, 

inhabited  twenty-two  centuries  ago. 

In  the  circle  at  the  upper  right  is  Chief  Evergreen  Tree,  whose  war-bonnetted  ancestors 

looked  in  awe  upon  the  advances  of  the  encroaching  white  men.     Radio  station  KOA, 

located  in  the  heart  of  this  age-old  civilization,  broadcast  the  first  information  concerning 

the  discoveries  a  few  weeks  ago. 


region.  This  area  measures  fourteen 
miles  in  length  and  one  and  one-half 
mile  in  width. 

That  the  lost  city  antedated  cliff  dwell- 
ings by  at  least  1000  years,  archeologists 
are  certain. 

"When  Socrates,  condemned  to  death, 
was  drinking  hemlock  in  his  cell  at 
Athens,    in    the    'old'    world,    this    great 


population  of  a  brown  race,  that  builded, 
flourished  and  then  disappeared  mys- 
teriously, had  emerged  from  a  semi- 
savage  state  to  one  of  distinct  culture," 
Mr.  Smith  told  his  radio  audience. 

"There  is  little  doubt  that  the  city  was 
a  continuous  habitation  of  many  thou- 
sands of  humans,"  he  continued.  "Tens 
of  thousands  of  pithouses,  (To  page  48) 


RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doing  29 


BY  MARIE  SHIELDS 
HALVEY 


The  World  s  Biggest  Radio  Organ 

—And 

The 

Littlest 

Organist 

€[How  the  Prim 
Little  Organist 
of  Station  WOO 
is  Proving  All 
Bobbed  Meads 
Are  Not  Empty 


THE  Wanamaker  Grand  Organ  is  an 
institution  in  Philadelphia.  Visitors 
are  taken  to  see  it  along  .with  thV 
Navy  Yard  and  the  house  where  Betsy 
Ross  lived.  Thousands  stand  daily  in  the 
transept  of.  the  store  to  listen  to  its 
splendid  harmonies..  It  has  five  manuals 
and  more  than  eighteen  thousand  pipes,, 
and  the  organist  who  sits  at  the  console 
and  makes  all  this  magnificence  "go,"  is 
a  little  slip  of  a  girl,  not  much  more  than 
five  feet  in  height  and  slender,  as  a  boy, 
w-ith  a.  mop  ..of  thick  black  curls  and 
bright,  snapping"  brown  eyes. 

Her  name  is  Mary  E.  Vogt,  and  the 
story  of  her  life  reads  like  a  fairy  tale 
where  the  fairy  godmother  arrived  at 
life's  darkest  moment  and  the  good  child 
was  started  on  the  road  to  success. 

Obliged  to  leave  school  when  she  was 
fourteen  to_  help  with  the  support  of 
younger  children  at  home,  fate  guided 
Miss  Vogt  into  the  employ  of  a  great 
and  good  man;  a  man  whose  far-reaching 
vision  saw  the  little  girls  and  boys  in  his 
great  store  not  as  poor  little  wage  earners, 
handling  stock  or  running  errands,  but 
as  citizens  of  the  future;  as  men  and 
women  who  must  take  their  places 
eventually  in  the  social,  business  and 
artistic  life  of  the  city  that  he  loved. 

Real  Talents  Developed 

XJE  was  the  first  to  develop  in  his  own 
-*--*-  establishment  the  idea  later  em- 
bodied by  the  Board  of  Education  in 
what  are  now  known  as  continuation 
schools.  Attendance  at  the  store  school 
was  compulsory.  Trained  educators 
supervised  the  studies  and  watched  for 
signs  of  any  natural  aptitude  in  one 
field     or     another.         Salesmen,     buyers, 


■Mere  is  Mary  E.    Vogt,  the.  diminutive  organist  of  station   WOO,   in  a  restful  moment 

before  the  console  of  the  great  Wanamaker  organ  in  Philadelphia.      Miss  Vogt  is  a  human 

though  serious-minded  young  person,  and.shi  thinks  girls  can  amount  to  something  besides 

serving  as  stylish  ornaments. - 


accountants,  mechanical  experts  of  var- 
ious kinds  were  developed  under  this 
plan.  Whatever  the  kind  of  ability  the 
child  showed,  he  or  she  was  encouraged 
to  specialize  along  that  line. 

It  was  not  long  before  the  little,  brown- 
eyed  Mary  Vogt  gave  evidence  in  plenty 
that  her  future,  rightly  directed,  lay  in 
the  world  of  music.  From  that  point  the 
fairy  godmother  took  her  in  hand.  She 
was  set  to  study  music  under  Dr.  J. 
Lewis  Brown,  then  musical  director  for 
the  Wanamaker  stores.  In  a  surprisingly 
short  time,  she  was  working  in  the  sheet 
music  department,  playing  selections  re- 
quested by  customers.  For  five  years 
now  she  has  been  the  official  performer 
on  the  great  organ  and  musical  director 
for  the  store. 

The  music  of  the  grand  organ  was 
introduced  to  the  radio  public  two  years 
ago  through  the  medium  of  WOO,  the 
broadcasting  station  of  the  Wanamaker 
store  in  Philadelphia.  Miss  Vogt  does 
not  do  any  announcing.  Among  the 
things  she  emphatically  dislikes  are 
women's  voices  over  the  radio,  germs 
and  cross-word  puzzles.  She  has  the 
radio  headquarters  regularly  scrubbed 
and  disinfected,  and  she  won't  allow  the 
girls  in  her  office  to  work  at  the  puzzles. 

"The  young  mind  of  today,"  said 
Miss  Vogt,  "needs  to  read  good  books 
and  hear  real  music.     To  see  in  the  dic- 


tionary the  meaning  ot  an  obsolete .  or 
little  used  word  from  a  cross-word  puzzle 
has  no  educational  value.  They  might 
be  more  profitably  employed  listening 
to  a  good  concert." 

Interested  in  "Kids" 

'  I  ''HE  young  mind  of  today  interests 
-*-  her  even  more  than  the  gorgeous 
organ  she  plays  so  well.  She  teaches  now 
in  the  store  school  where  she  received  her 
own  training,  and  she  finds  her  greatest 
delight  in  guiding  these  young  girls  and 
boys  into  the  career  for  which  they  are 
fitted,  even  as  she  herself  was  guided 
into  the  realm  of  music. 

Miss  Vogt  is  deeply  interested  in  the 
development  of  the  radio.  Like  other 
directors  who  arrange  programs  for 
broadcasting,  she  deplores  the  tendency 
of  the  fans  to  explore  the  air — in  other 
words,  to  jump  from  one  program  to 
another  as  the  signals  indicate  what  they 
have  picked  up.  Any  cultural  value 
radio  may  have  is  ruined  by  this  practice. 
Miss  Vogt  hopes  to  see  at  no  distant  date 
broadcasting  reduced  to  a  few  great 
high-power  stations,  with  programs  of 
the  highest  quality  relayed  by  local 
broadcasters. 

She  is  right  up-to-date  on  the  mechan- 
ical end  of  radio,  too,  and  can  talk 
familiarly  about  the  latest  inventions 
for  improving  transmission 


30 


RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doing 


Review  of  Radio  Ages  Contest  Shows 


"The  Three  Musketeers' 

FIGHTING  For 
Winner's  SHIELD 

Bv  HARRY  ALDINE 


MIDNIGHT  of  June  fifteen  will 
see  the  end  of  the  RADIO  AGE 
Popularity  Contest,  and  be- 
cause of  the  closeness  of  the  hour,  we 
were  tempted  to  digress  from  our  usual 
custom  of  naming  a  monthly  winner. 
The  fact  is  that  in  reviewing  the  three 
leading  contestants  there  is  named  the 
man  who  secured  the  greatest  number  of 
ballots  for  the  month  of  April — Bert 
Davis — but  were  we  to  devote  this  page 
exclusively  to  him,  we  would  be  doing  a 
grave  injustice  to  the  other  two,  Karl 
Bonawitz  and   Bill  Hay. 

At  the  beginning  of  this  contest  it  was 
the  opinion  of  the  Contest  Editor  that 
there  might  be  aroused  a  greater  per- 
sonal interest  in  the  candidates  by  each 
month  selecting  one  of  them  for  a  brief 
story.  Whom  to  choose  each  month 
without  a  show  of  partiality  was  the 
next  factor  to  consider.  And  so  it  was 
decided  to  put  this  problem  squarely 
up  .to  the  readers  of  RADIO  AGE.  This 
wasaccomplished  by  naming  as  a  monthly 
winner  the  candidate  receiving  the 
greatest  number  of  votes  through  the 
period  of  each  thirty  days. 

How  It   Was   Done 

TT  SO  happened  that  in  seven  of  these 
•*•  ten  months  the  honor  was  attained  by 
different  candidates,  but  in  the  other 
months  where  a  candidate  repeated  his 
former  record  by  coralling  the  greatest 
number  of  ballots,  the  writeup  was 
handed  to  the  next  favorite  in  line. 

Karl  Bonawitz,  Bert  Davis  and  Bill 
Hay  are  the  three  to  whom  goes  the 
distinction  of  having  twice  secured  the 
greatest  number  of  monthly  votes,  and 
reference  to  the  "standing  to  April   15" 


POPULARITY  CONTEST  COUPON 

Harry  Aldine,  Contest  Editor 

RADIO  AGE,  500  N.  Dearborn  St.,  Chicago. 

I  wish  to  cast  my  vote  for: 


Nan 


of  favorite- 


Classification . , 

Station . Date  Heard. 

Name  (optional) '. 

Address  (optional) 


will  show  these  same.  "Three  Muske- 
teers" at  the  point  of  vantage  at  the 
head  of  the  list.  There  is  always  present 
the  probability  of  a  dark  horse  coming  to 
the  front,  but  if  present  figures  mean 
anything,  it  will  be  one  of  these  three 
who  heads  the  list  when  the  final  count 
is  taken. 

Of  the  three,  Karl  Bonawitz  has  so 
far  proven  to  be  most  consistent.  Get- 
ting off  for  an  early  start,  he  improved 
his  position,  reaching  first  place  seven 
months  ago,  which  standing  he  has  held 
up  to  the  present  time.  This  popular 
organist,  however,  is  being  closely  pressed 
by  the  other  two  artists. 

Bert  Davis,  on  the  other  hand,  per- 
formed in  an  erratic  manner,  twice  hav- 
ing secured  a  good  lead  only-  to  lose 
ground  in  succeeding  months.  The 
period  from  March  16  to  April  15  saw 
him  suddenly  spurt  from  seventh  to 
second  place.  The  next  thirty  days  will 
decide  the  fate  of  this  eccentric  enter- 
tainer. 

Bill  Hay  Holds  Own 

TTOLDING  a  close  third  position,  Bill 
-*-J-  Hay  had  been  sharing  second  and 
third  place  with  H.  W.  Arlin  in  the  earlier 
stages  of  the  contest.  At  one  time  he 
was  first  on  the  list  and  at  no  time  has 
he  dropped  below  third.  He  has  held 
second  post  during  the  two  preceding 
months.  This  popular  Announcer-Enter- 
tainer is  to  be  reckoned  with  before  the 
final    count    is    taken. 

It  will  be  seen  by  further  reference 
to  the  present  standing  that  Art  Linick 
and  Tee  Sims  have  strengthened  their 
positions.  The  latter,  although  a  new- 
comer in  the  field,  leaped  the  hurdles 
from  twenty- second 
to  twelfth  place.  The 
Gold  Dust  Twins  of 
WEAF  also  appear 
upon  the  scene. 

H.  W.  Arlin,  Coon 
and  Sanders'  Night- 
hawks,  Jack  Nelson 
and  Harry  Snodgrass 
all  seem  to  be  within 
striking  distance  of 
the  victor's  shield. 
But  that  is  a  story  in 
itself  to  be  told  after 


the    final     ballots    have     been   cast   and 
counted. 

WHEN  this  contest  was  started, 
RADIO  AGE  expected  an  enthusi- 
astic response  from  readers  and  radio 
fans,  but  nothing  was  dreamed  of  that 
compares  with  the  avalanche  of  votes 
which  has  deluged  the  Contest  Editor 
during  the  past  few  months. 

A  separate  department  had  to  be 
created  to  handle  the  volume  of  cor- 
respondence and  votes,  and  every  effort 
was  made  to  see  that  the  contest  was 
conducted  according  to  Hoyle,  and  that 
no  one  received  more  than  his  just  share. 

It  has  been  gratifying  indeed  to  learn 
with  what  respect  the  army  of  radio  fans 
hold  the  announcers  and  entertainers 
who  perform  for  them  nightly  over  the 
ether  waves.  It  is  only  fitting  that  the 
beautiful  shield  RADIO  AGE  has  ob- 
tained be  presented  to  the  winner  of  the 
RADIO  AGE  Radio  Favorite  Popularity 
Contest.  A  reproduction  of  the  shield  will 
be  published  in  the  July  RADIO  AGE, 
and  the  final  count  in  the  August  issue. 

Here's  the  way  it  looks  to  date: 

THE  WINNERS  FOR  APRIL 
A  review  of  the  three  leading  candidates: 
Karl  Bonawitz,  Bert  Davis,  Bill  Hay. 
WINNERS  OF  PRECEDING  MONTHS 

July Duncan  Sisters,  KYW 

August Bill  Hay,  KFKX 

September Karl  Bonawitz,  WIP 

October H.  W.  Arlin,  KDKA 

November Bert  Davis,  WQJ 

December Jack  Nelson,  WJJD 

January Art  Linick,  KYW 

February Coon-Sanders  Orchestra,  KYW 

March John  S.  Daggett,  KHJ 

STANDING  TO  APRIL  15 
Name  and  Classification  Where  Heard 

Karl    Bonawiti,    Organist WIP,    Philadelphia 

Bert      Davis,      Entertainer WQJ,      Chicago 

Bill  Hay,   Announcer KFKX,   Hastings 

H.   W.    Arlin,    Announcer KDKA,    Pittsburgh 

Coon-Sanders'  Nighthawks,  Orchestra,  KYW,  Chi. 

Jack    Nelson,     Announcer WJJD,     Mooseheart 

Harry   M.   Snodgrass,   Entertainer 

WOS,    Jefferson    City 

Art    Linick,    Entertainer KYW,    Chicago 

John  S.  Daggett,  Announcer KHJ,  Los  Angeles 

Ford  05  Glenn,  Entertainers WLS,  Chicago 

Duncan    Sisters,    Entertainers KYW,    Chicago 

Lee  Sims,  Pianist KYW,  Chicago 

Lambdin    Kay.    Announcer WSB,    Atlanta 

J.  Remington  Welsch,  Organist- KYW,  Chicago 

Fred  Smith,  Announcer WLW,  Cincinnati 

E.     L.     Tyson,     Announcer WWJ,     Detroit 

Hired   Hand,    Announcer WBAP,    Fort   Worth 

"Sen"     Kaney.      Announcer KYW,     Chicago 

Nick  B.  Harris,  Entertainer.. ..KFI,  Los  Angeles 
Jerry  Sullivan,  Announcer-Entertainer,  WQJ,  Chi. 
Edward     H.     Smith,     Director-Player 

.  WGY,  Schenectady 

Charles  E.  Erbstein,   Announcer WTAS,  Elgin 

Wendell  Hall,  Entertainer WDAF,  Kansas  City 

Howard    Milholland,    Announcer.. ..KGO,    Oakland 

Scottish    Rite,     Orchestra.... KGO,     Oakland 

Banks  Kennedy,  Entertainer WEBH,  Chicago 

S.    Hastings.    Announcer KFI,    Los   Angeles 

Robert  Boniel,   Announcer WEBH,   Chicago 

Arion  Trio,  Instrumental KGO,  Oakland 

Gold  Dust  Twins,  Entertainers.WEAF,  New  York 

There  remains  but  thirty  days  from 
the  time  this  June  issue  first  reaches 
the  news-stands  in  which  to  cast  your 
final  vote  for  your  radio  favorite.  If 
you  have  not  voted  before,  your  ballot 
may  be  the  one  to  decide  the  contest  for 
your  choice.  Those  who  have  been 
casting  their  ballots  each  month  are 
invited  to  clip  the  coupon  for  the  last 
time  and  send  it  in  with  the  name  of  your 
candidate. 

Let's  go  for  the  final  pull,  and  may  the 
best  man  win! 


RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doing 


31 


Opening  a 

NEW    ERA 
in  Radio 


CThree  Radio  Pioneers 
to  Lead  Short  Wave 
Expedition  into  Far 
North  to  Explore  the 
Arctics  and  Test  Out 
New    Radio  Theories 

By  FREDERICK  SMITH 


Above  is  shown  the  "Bowdoin,"  the  ship  which  carried  MacMillan 
to  the  Arctics  last  year.      It  is  seen  frozen  in,  near  the  Pole.     Com- 
mander MacMillan  is  shown  in  the  inset.      The  lower  photo  shows 
H.  C.  Forbes,  John  L.  Reinartz  and  Karl  Hassel,  designers  of  th 
Zenith-Reinartz  transmitter  to  be  used  in  the  1925  expedition. 


RADIO,  history  and  science  are 
likely  to  share  richly  in  the  results 
of  the  arctic  expedition  which 
■will  set  off  from  Wiscasset,  Me.,  about 
June  20  of  this  year.  There  will  be  one 
ship  and  at  least  two  seaplanes  to  carry 
northward  a  group  of  men  who  will  in- 
clude in  their  number  distinguished  radio 
engineers,  world-famous  navigators  and 
explorers,  and  some  of  the  best  aviatiors 
to  be  found  in  the  United  States  Navy. 

By  the  efforts  of  these  men  it  is  hoped 
that  a  new  era  in  short  wave  radio  trans- 
mission  will   be  inaugurated.      It  is  an- 


ticipated that  we,  in  the  more  comfortable 
latitudes,  may  even  be  privileged  to 
listen  to  the  folks  songs  of  the  polar 
Esquimeaux,  for  both  ship  and  airplanes 
will  carry  equipment  for  transmitting 
and  receiving  radio  messages. 

It  is  hoped  that  a  lost  arctic  continent 
may  be  located  and  that  landing  posts 
may  be  arranged  in  such  hitherto  in- 
accessible spots  that  the  cause  of  world 
commerce  and  communication  will  be 
immensely  benefited.  Planes  equipped 
with  mapping,  still  picture  and  moving 
picture  cameras,   will   fly  beyond    limits 


of  dog  team  travel  and  bring  back  tacts 
abouc  what  lies  in  the  land  of  frozen- 
mystery. 

To  Delve  Into  History 

IN  addition  there  will  be  original  re- 
search into  such  historical  data  as 
may  still  exist  relating  to  the  landing  of 
the  Norsemen  in  the  farthest  North. 
An  effort  also  will  be  made  to  obtain 
copies  of  the  important  records  left  by 
Peary  at  Cape  Columbia. 

Among  those   who  will  participate  in 
(Turn  the  page) 


32 


RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doing, 


this  series  of 
dashes  into  lands 
where  white  men 
have  not  before 
been  privileged 
to  go  are  the  fol- 
-  lowing: 

Donald  B. 
MacMil  Ian, 
Commander  in 
the  navy  and 
leader  of  the  ex- 
pedition. Com- 
mander MacMil- 
lan  is  a  scientist, 
explorer,  author, 
navigator,  lec- 
turer. 

Eugene     F. 
McDonald,  Jr., 
President  of  the 
National    Asso- 
ciation of  Broad- 
casters and  Presi- 
dent of  the  Zenith 
Radio     Corpora- 
tion,   Chicago. 
Commander  Mc- 
Donald,   himself 
a  n      experienced 
navigator  and 
hunter,    was    re- 
sponsible for  the 
installation  of 
radio  equipment 
on     the     little 
schooner     "Bowdoin"      when     it 
carried    Dr.     MacMillan    to    the 
Arctics    in    1923.     This   was   the 
first  demonstration  of    the  value 
of   radio   in   Arctic    explorations. 
Communication    was   established 
with  the  "Bowdoin"  after  it  went 
into     "Winter     quarters"    within 
thirteen  degrees  of  the  North  Pole 
and  was  maintained  for  months. 

U.  J.  Herrmann,  showman, 
sportsman,  founder  of  the  two 
great  annual  national  radio  ex- 
positions in  Chicago  and  New 
York  and  one  of  the  owners  of 
the  new  station,  WHT,  on  the 
Wrigley  Building  tower,  Chicago. 

John     L.     Reinartz,    famous 
radio   inventor,    designer   of    the 
Reinartz  circuit,    official    of    the 
American    Radio    Relay  League, 
pioneer    in    short    wave    develop- 
ment.     Lieut.    Reinartz   will    be 
official  broadcaster  for  the  MacMillan  ex- 
pedition and  will  conduct  tests  with  short 
wave    transmission,     which    will    engage 
the  attention  of  the  entire  radio  world. 
He  has  been  employed  permanently  by 
the  Zenith  Radio  Corporation,  332  South 
Michigan     avenue,     Chicago     and     will 
devote  much  of  his  time  before  the  ex- 
pedition sets  off  in  assisting  amaterus  in 
the  United  States  and  Canada  to  learn 
the    construction    of    short    wave    trans- 
mitters and  receivers,   which  will  be  of 
votal  importance  in  getting  messages  to 
and    from    the     MacMillan    expedition. 
The  Zenith  Corporation  will  build  these 
receivers   and   transmitters   only    for   its 
own   use,   both   on   the    MacMillan   ship 
and  in  its  own  transmitting  stations  in 
Chicago.     But  it  will  assist  all  who  wish 
to   build   the   instruments   with    free   in- 


The  upper  photograph  shows  Commander 
MacMillan  greeting  Eugene  F.  McDonald, 
one  of  the  sponsors  of  the  1925  trip  and  a 
seasoned  navigator  himself,  as  well  as  one  of 
radio's  leading  pioneers.  In  the  circle  is 
U.  J.  ("Sport")  Herrmann,  widely  known 
sportsman  and  showman,  who  will  accom- 
pany the  expedition. 


formation  on  application  by  _mail  to 
Lieut.  Reinartz.  The  Zenith  Corpora- 
tion says  it  hopes  to  have  1,000  amateurs 
equipped  with  short  wave  transmitters 
before  the  MacMillan  expedition  sails. 

Information  as  to  the  volunteer  naval 
aviation  personnel  which  will  be  a  part  of 
the  expedition  will  be  given  RADIO 
AGE  readers  in  a  later  issue. 

Short  Waves  Are  "Coming" 

POMMANDER  McDonald  predicted 
^- *  to  the  writer  more  than  a  year  ago 
that  the  radio  world  would  soon  be  pay- 
ing more  serious  attention  to  the  use  of 
short  waves  as  an  effective  means  of 
radio  communications.  His  plans  for 
the  equipment  of  the  artic  expedition 
prove  that  he  has  more  faith  than  ever 
in   this   employment   of   high    frequencies 


under  the  most 
difficult  condi- 
tions. 

He  submitted 
the  following 
facts  in  a  recent 
interview: 

Will   Carry 
Transmitters 

"The  Expedi- 
tion is  to  have 
four  transmit- 
ters, 20,  40,  80, 
and  180  meter 
wavelengths.  We 
will  be  in  twenty- 
four  hour  day- 
light after  we 
pass  66°30'  north 
latitude.  The  20 
meter  transmit- 
ter will  be  used 
when  we  are  com- 
municating dur- 
ing the  period  of 
the  day  when  this 
part  of  the  globe 
is  in  daylight;  40 
meters  when  this 
part  of  the  globe 
is  in  darkness. 
The  80  meter 
transmitter  is 
merely  to  be  used 
to  get  us  wider 
ci  rculation 
among  the  ama- 
teurs that  will 
be  able  to  reach 
down  to  that  point,  and  not  down 
to  20  meters.  The  180  meter 
transmitter  is  taken  along  merely 
for  the  purpose  of  proving  that  it 
will  not  work  in  these  high  lati- 
tudes, and  twenty-four  hour  day- 
"ight. 

"I  have  employed  Reinartz  at 
the  highest  salary  ever  paid  any 
radio  operator,  $1,000.00  a  month, 
and  this  is  not  stage   money.      I 
secured  him    because    I   believed 
him  to  be  the  short  wave  wizard 
of  the  United  States,  and  money 
is  no  object.     We  must  get  these 
messages    back   from   the    Arctic 
even  though  we  are  going  into  the 
most  difficult  section  of  the  globe 
for  radio  transmission.    One  hun- 
dred   meter    signals    have    never 
been  heard  in   Smith  Sound  be- 
tween 55o  n.l.  and  75°  n.l.     You 
will  recall  the  MacMillan  signals 
came   back  only  after  they   had 
passed  75°.    His  port  from  which 
he  sent  most    of  the  communica- 
tions  last   year  was  from  78:30. 
Planes  Will  Transmit 
"We  are  equipping  the  airplanes  with 
a  new  type  of  transmitter  using  40  meters. 
The  reason  we  cannot  use  20  meters  on 
the  airplanes  is  that  20  meters  are  not 
audible   at   distances   under   2500   miles. 
Forty    meters,    however,    are   audible   at 
all    short     distances.        Lieut.     Reinartz 
pointed  out  an  interesting   phenomenon 
the  other  day  when  he  told  me  that  while 
it  was  necessary  to  be  500  miles  away  to 
hear  20  meter  signals  in  the  daytime,  it 
was  necessary  to  be  3,000  miles  or  over 
to  hear  them  at  night. 

"The  transmitters  for  the  airplanes 
will  weigh  under  100  lbs.,  and  be  operated 
by  dry  batteries  only.  The  Government 
radio  equipment  today  for  airplanes  is 
operated  by  a  generator  propelled  by  an 
aeroplane  propeller,  and  therefore  will 
function    only    while    the    airplane    is  in 


RADIO  AGE  for  June,  1925 


What  the  Broadcasters  are  Doinz 


Here  is  a  typical  airplane  used  for  exploring  trips,  and  similar  to  the  'planes  which  will  be  taken  with  the 
Mac Millan- McDonald  Expedition  in  June,  when  they  set  out  for  their  perilous  dash  to  the  mysteries  of  the  north- 
land.     The  'planes  will  aid  the  explorers  in  guiding  the  ships  and  reaching  points  which  are  closed  to  navigation. 


commission.  If  the  airplane  motor  is  out 
of  commission,  so  is  the  radio,  and  we 
cannot  take  that  risk.  We  want  a  trans- 
mitter capable  of  sending  word  back  to 
the  ship  for  the  emergency  plane  to  come 
out  in  case  our  motor  fails  us  and  we  are 
forced  to  make  a  landing  far  from  our 
base. 

Daily   "Letters"   Home 

"We  hope  to  transmit  messages  back 
every  day.  Reinartz  confidently  hopes 
that  we  will  be  able  to  send  voice  back 
from  the  Artie  on  20  meters.  If  this  is 
possible  , we'll  give  you  the  Esquimeaux 
Folk  Songs  by  radio.  It  may  be  possible 
if  we  can  transmit  the  voice  back  to  pick 
it  up,  boost  it  in  wavelength,  and  put 
it  out  over  the  broadcasting  station 
WJAZ." 

THE  foregoing  shows  rather  impress- 
ively what  a  degree  of  thought  and 
effort  and  careful  engineering  is  being 
devoted  to  the  radio  phases  of  this  ad- 
venturous enterprise. 

While  the  expedition  has  the  cordial 
indorsement  of  the  National  Geographic 
Society,  to  which  plans  of  the  itin- 
erary already  have  been  submitted,  and 
although  President  Coolidge  has  not 
only  given  the  expedition  his  approval 
but  has  authorized  the  participation  of 
the  Navy  Department,  it  is,  after  all,  a 
private   enterprise. 

It  should  be  remembered  by  those  who 
prefer  to  know  who  are  the  most  useful 
friends  of  radio  that  the  negotiations  in 
Washington  were  conducted  successfully 
only  through  the  earnest  co-operation  of 
Secretary  Wilbur,  of  the  Navy  Depart- 
ment; Rear  Admiral  William  A.  Moffett, 
in  charge  of  naval  vaiation,  and  Con- 
gressman Fred  A.  Britten,  an  Illinois 
representative  who  repeatedly  has  come 
to  the  aid  of  the  radio  industry  and  the 
radio  fan.  It  was  the  vision  of  these 
three  men  and  their  vigorous  prosecution 
of  the  official  plans  which  made  the 
project  what  it  is  today,  one  of  the  most 
important  scientific  ventures  ever  under- 
taken. 

Will  Test  High  Frequencies 

As  a  result  of  all  this,  radio  high  fre- 
quencies will  have  their  chance  while  the 
world  stands  by  as  referee.  The  ancient 
ruins  in  Labrador  and  Greenland  will  be 


explored  to  connect  then,  if  possible,  with 
Eric  the  Red.  The  exploring  ship  will  try- 
to  make  its  way  to  Axel  Heiburg  land. 
It  is  planned  to  establish  an  airplane 
base  250  miles  away  from  the  ship  at 
the  northernmost  point  of  the  land. 

The  airplanes  will  have  a  cruising 
radius  of  1,000  miles  and  a  speed  of  120 
miles  an  hour.  They  will  try  to  fly  over 
the  Greenland  ice  cap,  where  no  man  has 
ever  been  before.  One  of  the  most  im- 
portant missions  of  these  planes  will  be 
the  mapping  of  Ellesmere  Land  and  Baffin 
Bay,  in  the  vicinity  of  the  magnetic 
north  pole. 

The  party  will  attempt  to  make  a  com- 
prehensive survey  of  the  only  remaining 
"blind  spot"  in  the  world — that  region 
of  more  than  a  million  square  miles  in 
extent,  which  is  hidden  away  at  the  top 
of  the  world  between  Alaska  and  the 
pole. 

In  the  projected  exploration  of  Baffin 
Land  there  is  a  fascinating  invitation  for 
Commander  McDonald  and  "Sport" 
Herrman,  both  doughty  disciples  of  Isaak 
Walton.  For  they  probably  will  find 
thousands  of  lakes,  hitherto  unfinished  by 
white  men.  Esquimeau  have  told  of 
enormous  numbers  of  seal,  caribou  and 
other   wild   animals   in   these   wilds. 

The  "Bowdoin"  will  sail  about  June  20 
and  from  that  date  forward  many 
hundreds  of  thousands  of  persons  will 
await  daily  the  news  of  this  intrepid 
assault  on  the  phalanxes  of  the  proud 
and  stubburn   north. 


England  Hears  Radio  From 
Hawaii 

WASHINGTON,  D.  C—  NRRL,  the 
amateur  experimental  radio  station 
operated  by  Lieutenant  F.  H.  Schnell, 
traffic  manager  of  the  American  Radio 
Relay  League,  with  the  United  States 
fleet  in  European  waters,  has  succeeded 
in  piling  up  some  enviable  records  in  the 
way  of  constant  communication  on  short 
wave   lengths. 

Several  stations  in  the  East  and  some 
on  the  Pacific  Coast  have  worked  with 
Lieutenant  Schnell,  while  stations  that 
have  heard  NRRL  run  from  California 
to      England.        British      station      g5NN 


picked  his  nessage  put  on  the  air  and 
relayed  the  information  back  to  League 
Headquarters  in  the  United  States  by 
radio. 

Stations  in  Rochester,  N.  Y.,  Brook- 
lyn, N.  Y.,  and  Longmeadow,  Mass., 
were  the  ones  on  the  Eastern  seaboard 
that  successfully  conversed  with  Lieu- 
tenant Schnoll,  while  Minneapolis,  Long 
Beach,  Cal.,  Altedena,  Cal.,  and  Ellens- 
burg,  Wash.,  also  carried  out  two  way 
telegraphy  with  Station   NRRL. 

Reports  have  been  made  to  the  Ameri- 
can Radio  Relay  League  headquarters 
in  this  city  by  stations  at  Gadsen,  Ala.; 
Baltimore,  Attleboro,  Mass.;  Schuylkill, 
Pa.,  New  York  City;  Red  Bank,  N.  J.; 
Port  Arthur,  Ont.;  Hilton,  N.  J.;  Mt. 
Ranier,  Md.;  Los  Angeles  and  Baker, 
Ore.,  that  Lieutenant  Schnell's  messages 
from  the  special  short  wave  station  were 
heard  and  copied  by  the  operators. 

China  to  Admit  Radio  Supplies 

Hartford,  Conn. — The  central  Chinese 
government  is  planning  to  lift  the  em- 
bargo on  radio  material  and  supplies, 
according  to  correspondence  of  the 
American  Radio  Relay  League,  whose 
headquarters  are  in  this  city. 

The  Peking  government  Department 
of  the  Telegraph  is  reported  at  work  on 
the  first  drafts  of  the  regulations  govern- 
ing  conditions   of   import. 

Those  who  advocate  the  removal  of 
the  restrictions  point  out  that  in  Man- 
churia there  are  radio  stations  in  opera- 
tion at  Mukden,  Changchun,  Harbin, 
Tungkiang,  Marchuli,  Yinkow  and  Hula- 
tao.  Others  are  in  course  of  construction 
at  Antung,  Tsitsihar  and  Tetropavlovsk, 
while  plans  for  other  stations  are  being 
considered. 

The  American  Radio  Relay  League 
correspondent  points  out  that  all  of 
these  stations  are  used  for  official  pur- 
poses only,  but  it  is  the  hope  of  radio 
enthusiasts  in  the  Chinese  republic  that 
they  may  be  opened  to  commercial  and 
other  uses  in  the  near  future. 

Vigilance  committees  designed  to  re- 
duce interfernece  in  radio  communica- 
tion have  been  formed  by  the  traffic 
department  of  the  American  Radio  Relay 
League  and  are  already  functioning. 


34 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Radio  Age  Institute 

Manufacturers'  Testing  Service 

A/f  EMBERS  of  the  staff  of  RADIO  AGE  will  be  pleased  to  test  devices 
■'■»■'■  and  materials  for  radio  manufacturers  with  the  object  of  deter- 
mining their  efficiency  and  worth.  All  apparatus  which  meets  with 
the  approval  of  various  tests  imposed  by  members  of  the  technical 
staff  of  RADIO  AGE  will  be  awarded  our  endorsement,  and  the  seal 
shown  to  the  right  will  be  furnished  free  of  charge.  Materials  for 
testing  should  be  sent  to 

RADIO  AGE  INSTITUTE 

504  N.  Dearborn  Street,  Chicago,  111. 


DEVICES 

displaying  this  seal 
have  been  tested 
and  approved  by 
the  RADIO  AGE 
INSTITUTE. 

Apparatus  illus- 
t  r  a  t  e  d  and  de- 
scribed below  has 
successfully  passed 
our  tests  for  June, 
1925. 


Test  No.  59. 
THOROLA 
Low  Loss 
D  o  u  g  h  n  ut 
Coils.  Manu- 
factured and 
submitted  by 
the  Reichmann 
Company  of 
I  Chicago.  These 
coils  embody  a 
new  type  of 
winding,  which 
p  ro  d  u  c  e  s 
a  very  good 
ratio  of  resist- 
ence  to  induct- 
ance, which  is 
a  true  measure 
of  coil  effici- 
ency.  This 
winding  minim- 
izes energy 
losses  in  induct- 
ance. Due  to  a  unique  and  scientific  shape  em- 
ployed in  this  coil,  called  "doughnut"  or  toroidal, 
selective  operation  is  easily  secured,  and  there  is  no 
undesirable  "pick-up"  as  in  open  coils.  The  coil  sub- 
mitted for  tests  was  found  to  satisfactory  pass  the 
tests  and  requirements  of  the  RADIO  AGE  institute 
over  the  period  in  which  it  was  used  in  our  laboratory. 

Test  No.  60. 
The  UNIVERSAL 
AERIAL  MAST 
FITTINGS,  manu- 
factured and  sub- 
mitted by  the  Uni- 
versal Mast  Com- 
pany of  3215  Mont- 
rose ave.,  Chicago, 
111.  These  fittings 
come  complete  in 
one  box  and  are  a 
welcome  surcease 
from  the  bother  of 
making  new  aerial 
supports  every  time 
a  fan  wishes  to 
erect  a  new  aerial,  after  moving,  etc.  The  material 
for  masts  using  these  fittings  should  preferably  be 
2  x  2  in.  cypress  or  yellow  pine.  The  bases  can  be 
attached  to  such  masts  very  easily.  The  guy  attach- 
ment, also  contained  in  the  kit,  is  fastened  one-third 
up  from  the  bottom  of  the  mast.  The  ends  of  the  base 
plates  may  be  flattened  down  to  give  additional  bear- 
ing surface.  These  fittings  were  tested  both  on  wooden 
and  on  apartment  building  roofs,  and  were  found 
practicable  for  both,  besides  being  unusually  firm 
against  the  wear  and  tear  of  wind,  rain.  etc.  Satis- 
factorily passed  the  tests  and  requirements  of  the 
RADIO  AGE    Institute. 


Test  No.  61.  RA- 
DION  BUILT  -  IN 
LOUD  SPEAKER 
HORN,  Manufactured 
and  submitted  by  the 
American  Hard  Rubber 
Co.  of  II  Mercer  St., 
New  York  City.  A 
unique  horn  barely  a 
foot  high,  which  can 
be  built  in  a  portable 
or  other  receiving  set, 
and  a  standard  head- 
phone unit  attached  to 
its  base.  May  also  be 
used  for  a  loud  speaker 
in  a  hotel  room,  etc., 
where  intense  volume 
is  not  desired.  Instead 
clear  and  sweet  tone  is 
produced.  The  horn  is 
made  of  RADION,  the 
American  Hard  Rubber 
Company's  material, 
also  used  for  radio  pan- 
els, etc.  The  horn  sent 
to  this  magazine  was 
tested  both  for  portable 
and  built-in  sets,  and  in 
every  way  satisfactorily 
passed  the  tests  and 
requirements  of  the 
RADIO  AGE  Institute. 


Test  No.  62.  SONORA  RADIO  SPEAKER, 
with  concealed  horn.  Submitted  by  the  manu- 
facturers. The  Sonora  Phonograph  Company  of 
New  York.  This  loud  speaker,  besides  being  of  un- 
usually attractive  design,  produces  very  clear  and 
deep  tone;  in  fact,  the  tone  is  almost  identical  with 
that  produced  by  high  class  phonograph,  having  been 
designed  after  that  style  and  with  that  end  in  view. 
A  patented  all-wood  horn,  the  same  as  used  in  the 
Sonora  Phonograph,  and  a  Sonora  tone  arm  and 
radio  reproducer,  are  encased  in  the  beautiful  cabinet, 
which  blends  with  the  furniture  of  any  home.  The 
speaker  is  small  enough  to  be  placed  on  a  table, 
mantel  or  on  the  radio  set  itself.  Satisfactorily 
passed  the  tests  and  requirements  of  the  RAD'O 
AGE  Institute. 


Test  No.  63.  MICA 
FIXED  CONDENSER, 
manufactured  and  submit- 
ted by  the  Sangamo  Elec- 
tric Company  of  Spring- 
field, 111.,  makers  of  elec- 
tric meters.  This  con- 
denser is  guaranteed  ac- 
curate within  10  per  cent 
of  the  marked  capacity  and 
to  sustain  its  original  accuracy  under  all  conditions. 
Their  accuracy  is  likewise  not  affected  by  the  heat 
or  acid  used  in  soldering.  These  condensers  show  up 
best  in  reflex  circuits  because  of  their  accuracy.  The 
condenser  is  sealed  in  a  smooth  brown  bakelite  case, 
making  it  impervious  to  atmospheric  changes.  Also 
presents  a  neat  appearance.  Satisfactorily  passed 
the   tests  and    requirements   of   the    RADIO   AGE 


Institute. 


Test  No.  64.  RA- 
DIO PLUG  sub- 
mitted by  Pacent 
Electric  Co.,  Inc., 
91  Seventh  Ave., 
New  York  City,  N. 
Y.  A  plug  for  con- 
necting either  a 
loud  speaker  or  a 
headset  to  the  out- 
put jack  of  any 
receiving  set.  It  is 
well  made,  having 
firm  grip  for  the 
telephone  or  loud- 
speaker tips.  Tested 
and  approved  by 
RADIO  AGE  In- 
stitute. 


Test  No.  65.  Metallized  Grid  Leak,  submitted  bv 
Durham  and  Co..  Inc.,  1936  Market  St.,  Philadelphia, 
Pa.  Consists  briefly  of  a  glass  rod  of  small  and  uni- 
form diameter,  coated  with  a  metallized  high  resist- 
ance material  by  means  of  a  high  temperature  and 
gas  process.  Resistance  then  impregnated  in  a  non- 
hydroscopic  insulating  fluid,  and  after  an  aging 
period,  is  cut  and  assembled  in  the  air  tight  cartridge 
The  end  caps  are  soldered  to  the  resistance  unit 
instead  of  using  low  melting  alloy.  Tested  and 
approved  by  RADIO  AGE  Institute. 


Test  No.  66.  SIL- 
VER "'TWO-TENS" 
and  "TWO-ELEV- 
ENS." Long  wave 
transformers.  Sup- 
plied in  sets  of  2  or  3 
2 1 0s  (iron  core  in- 
terstage and  one  211, 
(filter  for  input  or  out- 
put) with  identical 
peaks  and  separate 
curves.  The  feature 
of  these  transformers 
lies  in  the  fact  that 
the  makers  plot  the 
curve  in  their  own 
laboratory  and  record 
them  directly  on  a 
tag  attached  to  each 
transformer  before  it 
is  placed  on  sale.  Tests  to  determine  the  accuracy  of 
these  charted  and  matched  transformers  were  con- 
ducted in  this  magazine's  laboratory  and  in  every 
instance  the  tag  attached  to  each  transformer  was 
found  to  have  the  correct  curve.  Manufactured  and 
submitted  by  Silver-Marshall,  Inc.,  105  S.  Wabash 
Ave.,  Chicago.  Satisfactorily  passed  the  tests  and 
requirements  of  the  RADIO  AGE  Institute. 


Test  No.  67.  The  Remo  RADIO  TUBE  REACT- 
IVATOR. Manufactured  by  the  Remo  Corporation 
of  Meriden,  Connecticut.  An  instrument  selling  at  a 
reasonable  price  for  reviving  weak  or  old  tubes  and 
bringing  them  back  in  volume  as  good  or  better  than 
new  ones.  Designed  for  standard  amplifying  tubes  of 
the  UV201A  type  or  UV199  tubes.  Three  UV201A 
or  two  UV199  tubes  can  be  accommodated  at  once. 
Detector  tubes  of  the  UV200  or  WD12  type  cannct 
be  revived.  The  Remo  Reactivator  is  used  only  with 
regular  1 10  volt  60  cycle  AC  current  and  is  furnished 
with  cord  and  plug.  While  such  a  device  is  com- 
paratively new  in  the  radio  field,  the  Remo  React- 
ivator satisfactorily  passed  strict  tests  of  the  RADIO 
AGE  Institute  in  the  tests  for  which  it  was  used. 


Test  No.  68.  1926  MODEL  NEUTROWOUND 
RECEIVER.  A  new  principle — incorporated  in  the 
Neutrowound  Radio  Receiving  Set — enables  the 
operator  to  "tune  in"  near  or  distant  stations,  and 
operate  at  the  highest  peak  of  radio- frequency 
amplification — at  all  wave  lengths — insuring  con- 
sistent reception,  over  very  great  distances  with  the 
maximum  selectivity — free  from  outside  interference. 
The  all-metal  case  not  only  serves  as  a  sturdy  pro- 
tection for  the  vital  parts  of  the  receiving  set,  but 
also  acts  as  an  electro-magnetic  shielding  against 
outside  interference.  Howls,  noises  and  distortions 
are  eliminated.  Satisfactorily  passed  the  tests  and 
requirements  of  RADlO  AGE  Institute. 


Test  No.  69. 
VALLEY  BAT. 
TERY  CLIP. 
Submitted  by  the 
Valley  Electric, 
Company  of  St. 
Louis,  Mo.  This 
clip  is  of  the  con- 
ventional type  in 
use  for  A  battery  connections,  having  firm,  toothed 
jaws  for  gripping  the  positive  or  negative  posts  on 
batteries.  A  screw  is  provided  for  making  firm  con- 
tact with  the  wire.  Satisfactorily  passed  the  tests 
and  requirements  of  RADIO  AGE  Instrtute. 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


35 


Economy  of  Parts  and  Space  in 

A  3-Tube  Portable  Reflex 


By  JOHN  B.  RATHBUN 


TO  BE  truly  portable,  according  to 
my  idea,  means  that  a  receiving 
set  should  be  easily  carried  about 
from  place  to  place  without  seriously 
straining  its  owner's  physiology,  and  at 
the  same  time  it  should  be  so  compact 
that  it  will  not  take  up  any  more  room 
than  necessary  in  a  trunk.  There  are 
portables  and  portables,  but  the  absolute 
zero  in  portability  is  the  set  made  up  in 
a  traveler's  sample  case  which  weighs 
about  100  pounds  and  occupies  about 
fifty  per  cent  of  the  trunk  space.  On  the 
other  extreme  is  the  freak  midget  set 
which  has  been  variously  fitted  into  pill 
boxes,  fountain  pens  and  pickle  bottles, 
and  which  has  absolutely  no  purpose  in 
life  except  to  exhibit  the  make's  in- 
genuity. The  real  portable  should  have 
a  good  range  and  sufficient  volume  to 
operate  a  loud  speaker,  and  yet  at  the 
same  time  should  not  take  up  a  great 
deal  more  space  than  a  camera,  even 
when  fully  equipped  with  batteries. 

No  really  practicable  portable  has 
been  turned  out  with  less  than  three 
tubes,  for  it  is  impossible  to  operate 
a  loud  speaker  satisfactorily  with  less 
tubes  on  anything  but  local  stations. 
For  this  reason  I  will  assume  a  three 
tube  set  from  the  beginning  and  will 
build  up  all  the  other  data  about  this 
premise.  Whether  this  is  to  be  a  regen- 
erative, radio  frequency  or  reflex  still 
remains  to  be  seen,  but  as  the  maximum 
volume  is  to  be  obtained  from  a  minimum 
number  of  tubes  and  batteries,  I  have 
strong  leanings  for  the  refle-x  type.  The 
reflex  circuit  is  not  always  the  greatest 
distance  getter,  but  what  it  does  get, 
it  gets  good  and  loud. 

Batteries  Consume  Space 

T)ROBABLY  the  most  important  item 
•*-  in  a  portable  is  that  of  the  batteries, 
for  the  batteries  weigh  more  and  take 
up  more  space  than  the  rest  of  the  equip- 


Copyright:    1925 


Reversed  Capacity 
Feedback  Cuts  Out 
Free    Oscillations 


ment.  Our  current  supply  system  must 
be  reduced  to  the  lowest  possible  limit 
even  at  some  sacrifice  in  the  life  of  the 
batteries.  If  the  batteries  stand  up  for 
a  month  while  traveling  about,  it  is  gen- 
erally considered  satisfactory  for  vaca- 
tion tours.  At  home,  we  can  substitute 
larger  batteries  installed  outside  the  set, 


"EVERYTHING  I  NEED 
IN  RADIO" 

"I  bought  a  copy  of  the  RADIO 
AGE  ANNUAL  for  1925  and  I 
found  that  everything  I  wanted 
to  know  about  radio,  from  crystal 
sets  to  complicated  multi-tubers, 
was  contained  between  its  two 
covers,"  wrote  an  enthusiastic 
beginner. 

"I  never  knew  so  much  could  be 
contained  in  one  book  without 
crowding  or  omitting  necessary 
details.  But  you  haven't  left  a 
thing  out  of  the  ANNUAL  for 
1925." 

Letters  such  as  the  above  are 
sent  to  us  every  day,  voicing  sin- 
cere appreciation  of  the  ANNUAL 
for  1925,  the  most  complete  radio 
hookup  book  ever  printed.  And 
the  price  for  the  120  pages  of 
technical  "nuggets"  is  but  ONE 
DOLLAR,  postpaid. 

Send  your  order  now  while 
our  supply  of  the  limited  first 
edition  lasts. 


Blueprints  of  the  3-Tube  Portable  Reflex  on  Two 


but  in  touring,  the  space  and  weight  are 
the  principal  items.  With  this  idea  in 
mind,  we  will  study  the  battery  situa- 
tion and  the  proper  tubes  to  go  with 
these  batteries. 

Storage  batteries  are  out  of  the  ques- 
tion, of  course,  hence  only  dry  cells  are 
available  for  the  filament  and  plate 
current.  This  means  that  the  tubes 
must  either  be  of  the  WD-12  or  the  UV- 
199  type,  which  are  specially  designed 
for  dry  cell  service.  They  do  not  give 
the  volume  of  the  201A  power  tubes 
used  with  storage  batteries,  but  they 
give  excellent  results  if  properly  handled. 

The  WD- 11  and  WD-12  are  the  same 
tube  with  the  exception  of  the  base. 
The  base  of  the  WD-11  is  a  special  small 
size,  while  the  WD-12  fits  in  a  standard 
socket.  Both  tubes  operate  on  the  1.5 
volts  produced  by  a  single  dry  cell  and 
take  0.25  ampere  per  tube.  Each  tube 
therefore  takes  1.5x0.25  =0.375  watt, 
or  3-8  watt.  One  No.  6  dry  cell  is  pro- 
vided for  each  tube,  which  can  be  con- 
nected independently  to  each  tube  of  a 
multi-tube  set  or  to  a  multiple  connected 
battery  with  as  many  cells  as  tubes. 
As  0.25  ampere  is  the  rated  discharge 
rate  for  a  No.  6  cell,  it  is  not  possible 
to  use  a  smaller  batterv. 

Next  come  the  UV-199  or  the  C-299 
tubes,  which  require  3.0  volts  at  the  fila- 
ment, and  which  take  only  0.06  ampere 
of  current.  As  the  voltage  of  a  battery 
falls  off  with  use,  we  must  use  three  dry 
cells  in  series,  which  gives  us  a  total  of 
4.5  with  a  fresh  battery.  This  excess 
is  taken  care  of  by  a  30  to  40-ohm  rheo- 
stat, which  permits  the  use  of  a  battery 
between  the  limits  of  4.5  volts /and  3.0 
volts,  the  battery  being  discarded  iwhen 
the  voltage  drops  to  the  latter  point. 
The  power  taken  is  therefore:  4.5x0.06  = 
0.27  watt,  very  much  less  power  than  is 
required  with  the  WD-12. 

(Turn  to  page  38) 
Pages  Following 


®-£p 


38 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


(Continued  from  page  35) 

Qualities  of  "199"  Tube 

TVI  OT  only  is  the  power  loss  with  the 
i  i  UV-199  tube,  but  the  amplification 
is  greater  than  with  the  WD-12,  and  the 
199  is  much  more  satisfactory  in  the 
amplication  of  radio  frequency  currents 
in  reflex  sets.  In  fact,  the  199  comes 
next  to  the  201A  tube  in  regard  to  am- 
plication and  only  takes  one-quarter 
of  the  current.  Three  No.  6  "A"  batteries 
will  operate  three  199  tubes  for  a  long 
time,  for  the  discharge  rate  is  only 
3x0.06  =  0.18  ampere,  or  less  than  a 
single  WD-12  tube.  The  199  is  the  ideal 
tube  for  a  portable  set  from  many  stand- 
points, and  takes  up  a  minimum  of  room. 

As  the  rating  of  a  No.  6  dry  cell  is  0.25 
ampere  for  filament  lighting,  this  size 
of  cell  will  operate  three  199  tubes  for  a 
very  long  period,  much  longer,  in  fact, 
than  would  be  absolutely  necessary  with 
a  portable  receiver.  For  this  reason, 
we  can  use  a  smaller  filament  battery 
with  satisfactory  results,  and  if  the  set 
is  not  used  for  too  long  a  period,  a  4.5 
volt  C  battery  can  be  used  for  each  tube. 
As  the  C  battery  takes  up  much  less 
space  and  weighs  much  less  than  a  No. 
6  cell,  we  can  use  a  4.5  volt  C  for  each 
tube  or  a  total  of  three  C  batteries  in 
all.  For  home  use,  where  less  frequent 
replacements  are  desirable,  we  can  use 
a  larger  external  battery — a  storage 
battery  if  necessary. 

An  alternative  will  be  to  use  two  C 
batteries  in  parallel  for  each  tube.  This 
will  give  longer  life  than  the  singles  as 
connected  above,  but  will  take  less  space 
than  three  No.  6  cells.  The  following 
table    will    give    the    comparative    sizes: 

NO.  OF     SIZE  OF  SPACE 

CELLS      CELLS  OCCUPIED 

3  No.  6  5"x5"x6.5=  162.5  cubic  in. 
3  C  4.1"x3"x4"  =  49.5  cubic  in. 
6     C      4.1"x6"x4"   =  99.0  cubic  in. 

In  effect,  the  three  C  batteries  will  be 
connected  in  parallel  through  a  switch, 
and  we  will  use  the  C  batteries,  as  we 
wish  to  get  the  smallest  possible  set. 
If  longer  service  from  No.  6  cells  is 
required,  then  the  only  change  necessary 
will  be  to  use  a  single  group  of  three  cell 
in  series  of  the  No.  6  type,  and  to  corre- 
spondingly enlarge  the  battery  com- 
partment of  the  set. 

The  Hookup  in  Detail 

In  general,  the  "Junior  Reflex"  is  a 
regenerative  reflex  using  a  tube  detector 
with  a  tickler  coil  feed-back  and  equipped 
with  one  additional  stage  of  straight 
audio  frequency  amplification.  This 
arrangement  gives  us  one  stage  of  radio 
frequency  amplification,  a  regenerative 
stage,  and  two  stages  of  autio  amplifica- 
tion. Enough  for  three  tubes.  A  short, 
temporary  aerial  of  from  40  to  60  feet 
will  be  all  that  is  ordinarily  required, 
either  of  the  indoor  or  outdoor  type, 
and  I  have  had  good  service  with  a  30 
foot  indoor  aerial  run  around  the  picture 
moulding  of  the  room.  So  far  as  possible, 
small  or  miniature  parts  are  used  to 
economize  space,  and  it  is  surprising  how 
much  apparatus  we  can  get  into  a  small 
cabinet  when  we  make  up  our  mind  to 
concentrate  our  efforts  to  this  end. 


A  special  method  of  avoiding  oscilla- 
tions by  means  of  a  reversed  capacity 
feed-back  is  applied  to  the  radio  fre- 
quency tube,  which  has  proved  effective 
in  all  the  cases  experimented  upon  by 
the  writer.  The  plate  current  is  fed  back 
into  the  primary  of  the  tuning  coil 
through  a  very  small  variable  condenser 
in  such  a  way  that  it  opposes  the  free 
oscillation  tendency  of  the  first  tube. 
It  is  a  simple  application  of  the  reversed 
feed-back  system  without  the  necessity 
of  a  tickler  coil.  As  the  suppression  of 
free  oscillations  is  one  of  the  most  difficult 
propositions   met   with    by   the   amateur 


MATERIALS  FOR  "JUNIOR 
PORTABLE" 

Code  No.  of 

Letters  Pes.  Name  Size 

A — 3    'C"  batteries,  large.  4.5  volt. 

AFT — 2   Audio   Frequency   Transformers.    4-1    to    6-1 
ratio. 

B—  4    "B"'    batteries.    22.5    volt    blocks.      Small    size 
(1200  m.  h.). 

C1-C2 — 2    Vernier    variable    condensers.    0.C0035    mf 
17  plate). 

C3 — 1  Equalizing  variable  condenser.  Chelton    Midget, 
0.00006  mf. 

"C" — Small  bias  battery. 

D— 1  Bakelite  panel  10"x8  3-4"x3-16' . 

E— 1  Bakelite  tube  shelf  4"x6  l-8"xl-S". 

F — 6  Marked  binding  posts. 

GL — 1  Grid  leak  (adjustable  or  fixed).  1.0  to  2.0  meg- 
ohms. 

Jl —  1  Single  circuit  jack. 

Kl — 1  Fixed  condenser,  mica  ins.  type  0.001  mf. 

K2 — 1  Fixed  condenser,  mica  ins.  type  0.002  mf. 

K3 — 1  Fixed  condenser  with  leak  lugs  0.00025  mf. 

K4 — 1  Fixed  condenser  mica  ina.  type  0.00025  mf. 

R1-R3 — 2  Amperites  for  fila.  control  (199.  4.5  volts). 

R2 — 1  Filament  rheostat,  vernier,  40  ohm  type. 

RFT-1— 1   Standard  air  core   R.  F.   transform  neutro- 
dyne  type. 

RFT-2 — 1  Bakelite  tube.  2  1-4'  diam.  3"  long. 

RFT-2 — 1-4    lb.    silk    covered    magnet    wire    No     26 
D.  S.  C. 

S — 4  small  brass  shelf  or  support  angles 

12'  Bus  wire.  No.  14,  tinned  copper. 

1'    Rosin    core    solder. 

1'  Spaghetti. 

25  Miscellaneous  machine  screws. 

U— 2  Condenser  dials  (If  not  with  con.)  3"  Diam 

SW — 1  Battery  cutout  switch.  Standard. 

T1-T2-T3— 3  UV-199  tubes. 

V — 3  "199"  tube  sockets,  absorb,  base. 

W — 4  Condenser  angles  for  holding  coils  on  condensers. 

X — 8'  Flexible  fixture  cord  for  battery  connections. 
No.  18. 

Y — 1  Special  cabinet  (Complete). 

1  Phone  plug. 

60'  Annunciator  wire,  wax  cotton 
fixture  wire  for  aerial. 


IS   fle 


in  the  construction  of  a  reflex  circuit, 
he  will  find  this  a  most  important  point. 
Fig.  1A  is  a  schematic  diagram  of  the 
"Junior  Portable,"  showing  the  three 
tubes,  the  transformers,  and  all  con- 
nections. The  tube  (Tl)  is  the  reflexed 
radio  frequency  and  audio  frequency 
tube;  tube  (T2)  is  the  detector,  and  ' 
(T3)  is  the  straight  audio  frequency 
amplifier.  All  radio  frequency  stages 
are  tuned  by  variable  condensers  so  that 
the  maximum  amplification  peak  is 
attained,  and  at  this  same  time  this  is  a 
valuable  aid  to  the  selectivity  of  the  set. 
The  second  tuning  coil  or  radio  frequency 
transformer  is  of  a  special  type,  as  it 
contains  three  coils  which  act  respectively 
as  the  primary,  secondary  and  tickler 
coils.  Only  two  dials  are  required  for 
the  tuning  operation  proper,  the  regenera- 
tion being  controlled  by  the  detector 
rheostat,  a  method  that  is  entirely  prac- 
ticable with  a  vernier  rheostat,  and  which 
greatly  simplifies  the  construction  and 
tuning. 

At  RFT1  we  have  the  usual  aperiodic 
tuning  coil  with  the  primary  (P)  and 
the  secondary  (S)  which  is  tuned  by  the 
17  plate  (0.00035  mf)  variable  condenser 
(CI)  connected  across  the  secondary 
in  the  conventional  manner.  A  detail 
of  this  tuning  unit  is  shown  in  Fig.  IB, 
which  shows  the  principal  dimensions. 
There  are  58  turns  on  the  secondary 
and    12  turns  on   the   primary  coil    (P), 


with  a  separation  between  the  two  coils 
of  approximately  1-2  inch.  The  wire  is 
No.  26  D.  S.  C.  magnet  wire. 

Condenser  for  Suppression 

/"OSCILLATIONS  in  the  radio  fre- 
^--'  quency  circuit  are  suppressed  by 
the  very  small  variable  condenser  (C) 
connected  between  the  primary  coil 
(on  the  aerial  side)  and  the  plate  of  the 
first  tube  (Tl).  This  is  a  condenser 
such  as  the  "Chelton  Midget"  or  the 
"Amplex"  neutralizing  condenser,  having 
a  maximum  capacity  of  from  0.000025 
to  0.00006  mf.  This  is  somewhat  critical 
on  most  sets,  hence  the  condenser  (C3) 
is  represented  by  a  dial  on  the  front  of 
the  panel.  When  properly  adjusted 
the  first  stage  can  be  cleared  up  quickly 
and  easily  by  this  simple  adjustment. 

The  output  of  the  first  tube  passes 
through  the  primary  (P)  of  the  special 
transformer  (RFT-2)  which  transfers 
the  radio  frequency  current  to  the  de- 
tector tube  (T2).  This  coil  (P)  is  located 
about  1-4  inch  from  the  end  of  the  sec- 
ondary coil  (S),  and  at  the  other  end  of 
(S)  is  the  tickler  coil  (T)  provided  for 
regeneration  in  the  detector  stage.  All 
three  coils  are  in  fixed  relation  on  the 
same  tube,  and  the  detector  circuit  is 
tuned  to  wavelength  by  the  variable 
condenser  (C2)  connected  across  the 
secondary  coil  (S).  The  tickler  (T)  has 
about  25  turns,  the  secondary  (S)  has 
58  turns  and  the  primary  (P)  is  a  12 
turn  coil.  The  general  details  of  this 
coil  or  transformer  are  shown  by  Fig. 
1C,  but  it  may  be  found  necessary  to 
give  a  few  more  or  less  turns  on  (T)  until 
the  proper  regeneration  is  obtained  with 
the  vernier  rheostat  (R2)  turned  to  the 
"half-on"  position. 

As  the  current  flowing  through  the 
coil  (T)  is  almost  entirely  dependent 
upon  the  filament  emission,  and  hence 
the  rheostat  adjustment,  a  very  accurate 
rheostat  will  be  required.  A  40-ohm 
rheostat  will  be  found  about  right  at 
this  point  for  the  proper  control  of  regen- 
eration by  the  filament  emission  system. 
If  the  tube  has  to  be  turned  up  bright 
for  the  regenerative  effect,  increase  the 
number  of  turns  on  (T)  until  it  starts 
to  "flop  over"  with  the  rheostat  turned 
about  half  way  on.  The  regulating 
resistance  for  the  radio  reflex  tube  (Tl) 
is  an  Amperite  shown  at  (Rl),  and  a 
second  Amperite  is  at  (R3)  for  the  auto- 
matic control  of  the  amplifier  filaments. 
The  amplifier  tubes  (T1-T3)  are  not 
critical,  but  the  detector  tube  (T2)  is 
very  critical  so  that  a  rheostat  must  be 
used  instead  of  an  Amperite  at  this 
point. 

The  detector  tube  circuit  is  a  conven- 
tional feed-back  circuit  and  has  the  usual 
grid  condenser  (K3)  and  grid  leak  (GL). 
The  grid  leak  is  from  1  to  2  megohms, 
and  the  condenser  (K3)  is  probably  best 
at  0.00025  mf.  A  bypass  condenser 
(fixed)  is  placed  at  (K2)  which  is  of  assist- 
ance in  reducing  the  R.  F.  resistance  of 
the  detector  plate  circuit.  The  value 
may  range  from  0.001  mf  to  0.002  mf, 
depending  upon  conditions  in  the  circuit. 
The  circuit  tuning  condenser  (C2)  has 
a  capacity  of  0.00035  mf.,  so  that  (CI) 
and  (C2)  will  "log"  well  together. 

As  is  usual,  the  output  of  the  detector 


RADIO  AGE /or  June,  1925 


The  Magazine  of  the  Hour 


39 


tube  is  reflexed  back  to  the  first  tube 
(Tl)  by  means  of  the  audio  frequency 
transformer  (AFT-1),  the  latter  being 
in  the  grid  return  circuit  of  the  first 
stage.  This  can  be  any  make  of  trans- 
former having  a  ratio  varying  from  4-1 
to  6-1,  but  as  we  wish  to  gain  every 
inch  possible,  I  have  shown  the  miniature 
Premier  Hegehog  transformer  in  the 
picture  diagrams.  In  some  cases,  a 
0.00025  mf  fixed  condenser  (K4)  im- 
proves results  when  connected  across 
the  secondary  coil  of  (AFT-1),  and  again, 
this  seems  to  have  but  little  effect.  It 
seems  to  be  a  matter  of  experiment  with 
each  individual  set  to  determine  whether 
(K4)  should  be  used.  Its  effect  is  prin- 
cipally on  DX  rather  than  on  volume 
with  local  stations,  so  that  we  should  try 
for  distance  in  making  this  adjustment 
rather  than  to  experiment  for  volume 
alone. 

The  output  of  the  reflexed  tube  (Tl) 
now  passes  to  the  primary  coil  of  the 
second  audio  transformer  (AFT-2),  and 
this  latter  transformer  is  a  part  of  a 
straight  audio  stage  that  is  not  reflexed. 
Connections  are  made  to  (T3)  in  the  usual 
standard  manner,  and  the  total  output 
of  all  three  tubes  passes  out  through 
the  output  jack  (Jl)  to  the  phones  or 
loud  speaker.  This  is  not  a  complicated 
circuit  to  hook  up,  but  it  requires  some 
readjustments  as  with  any  reflex  circuit, 
particularly  in  regard  to  the  values  of 
the  bypass  condensers. 

For  the  smallest  portable  set,  three 
4.5  volt  "C"  batteries  are  used  for  the 
filament  current  as  at  (A1-A2-A3),  the 
cells  being  in  parallel  and  connected 
to  the  circuit  through  the  battery  cutout 
switch  marked  (SW). 

22.5  Volts  for  Detector 

T)LATE  or  "B"  battery  connections 
*-  are  tapped  according  to  the  require-  # 
ments  of  the  various  stages.  A  voltage 
of  22.5  volts  generally  proves  best  for 
the  detector  circuit  under  all  around 
conditions,  although  45  volts  may  give 
greater  volume  and  selectivity  on  local 
stations.  A  potential  of  45  volts  is  most 
effective  on  the  radio  frequency  tubes 
on  distance,  hence  a  45  volt  tap  is  indi- 
cated for  this  stage.  The  audio  stage 
requires  90  volts  for  the  best  performance, 
and  67  volts  gives  nearly  as  good  results 
with  one  less  block  of  "B"  battery.  The 
set  can  also  be  operated  with  45  volts  on 
the  audio  stage,  but  with  greatly  diminish- 
ed volume  on  all  stations.  I  do  not 
recommend  placing  the  full  90  volts  on 
the  radio  frequency  stage,  and  never  on 
the  detector  stage,  and  after  experiment- 
ing extensively  I  find  that  the  best  all 
around  results  will  be  found  with  the 
plate  battery  connections  as  indicated. 

Four  small  B  batteries  (90  vo'lts  total) 
can  be  used  for  this  set  and  will  last  most 
of  the  season.  The  smallest  B  batteries 
are  the  450  milliampere-hour  cells 
which  measure  2"  wide,  3-3-8"  long  and 
2-9-16"  high.  The  next  largest  size  take 
up  very  little  more  space  and  give  much 
longer  service.  This  is  the  1200  milli- 
ampere-hour size  which  is  2-9-16"  wide, 
4-1-6"  long  and  2-3-4"  high.  The  latter 
size  are  the  more  practicable,  especially 


with  three  tubes,  and  are  shown  in  the 
assembly  diagram.  With  three  tubes 
kicking  out  from  10  to  12  milliamperes, 
the  450  m.  a.  h.  type  does  not  last  very 
long  before  the  voltage  runs  down  and 
the  volume  falls  off. 

In  the  table  on  page  38  is  listed  all  of 
the  material  required  for  building  this 
set,  each  item  in  the  list  being  preceded 
by  a  letter  corresponding  to  the  letters 
on  the  diagram.  All  of  these  parts  are 
standard  and  the  majority  are  built 
by  a  number  of  radio  concerns  so  that 
it  will  not  be  difficult  to  pick  up  all  of  the 
parts  at  your  dealer's.  The  only  special 
parts  are  the  cabinet,  which  must  be 
built  to  fit  the  job  at  hand,  and  the  tun- 
ing coils  and  RF  transformer,  which  can 
easily  be  wound  up  at  home.  A  neutro- 
former  or  tuning  unit  can  be  purchased 
for  use  in  place  of  RFT-1,  but  RFT-2 
is  special  and  is  not  stocked. 


Outdoors  or 

Indoors — You 

Will  Find  All  Your 

Radio  Needs 

Satisfied  In 

RADIO   AGE 

Every  Month. 


Another  Blueprint 

Hookup  In  July 

RADIO  AGE— Out  June  15 


Fig.  2  shows  all  of  the  parts  connected 
up  in  "picture"  form  for  the  benefit  of 
the  novice  who  does  not  understand  con- 
ventional or  symbolic  diagrams.  Either 
Fig.  1  or  Fig.  2  can  be  used  in  making 
the  actual  connections,  for  both  show  the 
same  circuit  and  the  parts  are  lettered 
with  corresponding  letters. 

Fig.  3  is  a  rear  elevation  of  the  set  with 
the  back  panel  removed  and  shows  how 
the  parts  are  assembled,  ready  for  wiring. 
The  three  tubes  and  sockets  are  mounted 
on  the  top  of  the  shelf  (E)  while  the  audio 
transformers  are  hung  underneath.  This 
not  only  saves  room  but  it  also  shortens 
and  simplifies  the  wiring.  Of  course, 
machine  screws  must  be  used  for  this 
assembly  instead  of  the  more  usual  wood 
screws,  as  all  parts  are  fastened  to  bake- 
lite.  The  shelf  is  attached  to  the  panel 
by  means  of  the  small  brass  angle  brack- 
ets (S)  which  can  be  made  at  home  or 
purchased  at  almost  any  radio  store. 

I  wish  to  call  your  attention  to  the 
fact  that  the  two  radio  frequency  trans- 
formers or  tuning  coils  (RFT-1)  and 
(RFT-2)  must  be  placed  at  right  angles 
to  one  another,  as  shown,  to  prevent 
coupling  back  between  stages  and  to  pre- 
vent oscillations  being  set  up  by  induc- 
tion. The  coils  are  supported  by  brass 
lug  connections  to  the  terminals  of  the 
variable  condensers  so  that  their  weight 
is  substantially  supported.  It  should  be 
particularly  noted  that  the  stator  or  sta- 
Blueprints  of  the  3-Tube  Portable  Reflex  on  Two 


tionary  plates  of  the  variable  condensers 
(C1-C2-C3)  connect  to  the  grids  of  the 
tubes  to  prevent  the  body  capacity  effect 
from  being  carried  out  to  the  front  of  the 
panel  through  the  shafts  of  the  condensers. 
The  grids  are  at  a  high  potential,  and 
anything  connected  to  the  grids  is  easily 
affected  by  the  capacity  of  the  hand  and 
is  detuned  by  this  capacity  effect.  ■ 

All  of  the  batteries  are  carried  in  the 
bottom  of  the  cabinet,  very  closely 
packed  together  to  prevent  movement, 
and  connections  are  made  with  the  cir- 
cuit above  through  the  flexible  cords 
(X).  Connections  are  more  certain  and 
more  easily  made  if  "spade"  type  clips 
are  soldered  to  the  ends  of  these  cords. 
Do  not  use  solid  wire  for  this  purpose 
or  simple  cotton  covered  wire,  as  such 
wire  is  likely  to  short-circuit.  Flexible 
fixture  wire  has  a  rubber  covering  which 
is  further  protected  by  a  cotton  braid, 
making  a  short  circuit  unlikely. 

The  Aerial  Wire 

'  I  1HE  aerial  wire  can  be  a  temporary 
-*-  affair  run  around  the  picture  moulding 
of  the  room,  strung  up  temporarily  from 
room  to  room,  hung  between  trees  or 
other  supports.  It  is  connected  to  the 
antenna  post  (ANT)  with  the  other  end 
left  free  and  unconnected.  For  indoor 
service  about  60  feet  of  annunciator 
will  be  sufficient  and  no  supporting  in- 
sulators will  be  needed,  as  the  waxed 
cotton  cover  will  be  sufficient  insulation 
when  laid  along  the  plaster  of  the  walls 
or  along  wood  surfaces.  For  outdoor 
work,  or  where  it  is  likely  to  be  damp, 
a  wire  with  rubber  insulation  should  be 
used,  such  as  flexible  fixture  wire  or 
lamp  cord.  Lamp  cord  is  excellent  for 
this  purpose,  as  it  has  a  low  R.  F.  re- 
sistance and  is  sufficiently  flexible  to 
allow  winding  up  in  a  small  coil. 

After  cutting  the  batteries  into  circuit 
by  means  of  the  battery  switch  (SW), 
the  detector  rheostat  (R2)  and  the 
equalizing  condenser  (C3)  are  adjusted 
until  all  whistling  and  howling  stop. 
There  should  be  a  slight  hissing  or  frying 
noise  which  will  indicate  that  the  tubes 
are  functioning,  but  the  adjustments 
should  not  be  much  above  this  point. 
Next,  turn  the  wavelength  adjustment 
condensers  (CI)  and  (C2)  very  slowly 
and  at  about  the  same  rate  of  speed  until 
a  "station  whistle"  or  voice  is  picked  up. 
Juggle  the  condenser  dials  until  the  signal 
is  at  a  maximum,  and  then  manipulate 
the  detector  rheostat  (R2)  just  under 
the  point  where  it  is  about  to  break  down 
into  free  oscillations  and  where  the  sig- 
nal is  at  a  maximum.  Working  the 
detector  rheostat  in  connection  with  the 
condender  (C3)  will  give  the  maximum 
volume. 

Remember  that  (C3)  is  for  the  purpose 
of  checking  oscillations  in  the  radio 
frequency  circuit,  and  that  this  controls 
the  radio  frequency  circuit  in  about  the 
same  way  that  the  detector  rheostat 
controls  the  detector.  Howling  can  be 
checked  by  either  (C3)  or  (R2)  depending 
upon  whether  the  trouble  is  in  the  radio 
frequency  or  detector  circuits. 
_  The     selectivity     depends     upon     the 

(Turn  to  page  42) 
Pages  Following 


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42 


RADIO  AGE  ./or  June,  1925 


The  Magazine  of  the  Hour 


Battery  Problem  Easily  Handled 


(  Continued  from  page  39) 
distance  of  the  primary  coil  (P)  from  the 
secondary  (S).  The  greater  the  distance 
the  looser  will  be  the  coupling  and  the 
greater  the  selectivity.  This  applies  to 
both  (RFT-1)  and  (RFT-2).  Usually 
the  best  spacing  of  the  coils  is  as  shown 
by  Figs.  IB  and  1C,  but  with  some  types 
of  audio  frequency  transformers,  this 
must  be  increased.  The  wavelength 
range  is  determined  by  the  number  of 
turns  on  the  secondary  coils  (S),  and  as 
shown,  will  cover  a  range  of  from  200 
to  600  meters. 

Fig.  4  is  a  front  elevation  of  the  panel, 
showing  the  dials  and  other  controls. 
It  is  advisable  to  allow  the  cabinet  to 
project  beyond  the  panel  in  front  for  the 
protection  of  the  dials,  and  to  provide 
a  door  at  this  point,  so  that  the  set  can 
be  completely  closed. 

Trouble  Shooting 
Y^7"HEN  the  signals  are  weak  and  the 
"  '  selectivity  seems  poor,  the  trouble 
is  usually  due  to  coil  reversal;  that  is,  the 
various  coils  in  the  tuner  or  transformer 
do  not  bear  the  proper  inductive  relation 
to  one  another.  If,  for  example,  the  prim- 
•  ary  coil  should  be  connected  so  that  it 
produces  a  magnetic  field  that  opposes 
the  field  of  the  secondary  coil,  then  the 
output  will  be  practically  neutralized  and 
there  will  be  little  reception.  It  is  for  this 
reason  that  I  suggest  that  you  connect  up 
all  of  the  primary  coils  permanently  when 
you  wire  the  set,  and  make  temporary 
connections  to  the  secondary  coils  and 
tickler  coil  with  magnet  wire. 

After  you  connect  up  the  set,  you  can 
tune  in,  and  if  results  are  not  satisfactory 
at  the  first  attempt,  try  reversing  the 
connections  to  the  secondary  and  tickler 
one  at  a  time,  until  you  get  the  best 
results.  After  the  best  point  is  found, 
you  can  complete  the  wiring  by  substitut- 


ing soldered  bus  wire  connections  for  the 
temporary  wires.  This  may  save  you  a 
lot  of  work  and  should  be  observed. 

Be  sure  that  the  prongs  of  the  tubes 
are  making  proper  contact  with  the 
springs  in  the  sockets,  and  try  this  out 
before  you  screw  the  sockets  down  into 
place.  A  loose  tube  or  loose  contacts 
mean  all  kinds  of  trouble,  and  trouble 
that  is  difficult  to  remedy  after  the  set  is 
completed  and  in  the  cabinet.  Also 
carefully  examine  the  jack  connections, 
and  make  sure  that  a  projecting  lump  of 
solder  is  not  short-circuiting  the  jack. 
The  lugs  are  very  close  together  and  it  is 
easy  to  short-circuit  at  this  point. 

Use  only  the  small  "midget"  type 
variable  condensers  for  the  transfer  (C3). 
A  standard  condenser,  even  as  small  as  a 
three  plate,  is  much  too  large  to  cover  the 
range  even  with  all  of  the  plates  out  of 
engagement.  The  zero  capacity  of 
standard  condensers  is  very  frequently 
greater  than  the  maximum  capacity 
desired  at  (C3). 

Sometimes  reception  is  improved  by 
connecting  a  0.001  mf  fixed  condenser 
across  the  ends  of  the  jack  (Jl),  and  some- 
times this  has  no  effect  at  all.  It  all 
depends  upon  the  winding  characteristics 
of  the  coils  in  your  phones  and  speaker. 

In  making  battery  connections,  be 
sure  that  the  positive  pole  of  your  "B" 
battery  is  connected  into  circuit  at  the 
point  indicated  in  the  drawings,  that  is, 
the  positive  of  the  "B"  battery  must 
always  go  to  the  plate  directly,  or  to  the 
plate  through  the  tickler  coil  or  trans- 
former primary.  If  this  polarity  is  not 
observed,  the  set  will  be  absolutely  dead 
without  a  hiss  or  grunt  to  be  heard. 

A  biasing  "C"  battery  for  the  grid  of 
the  audio  amplifying  tube  (T3)  can  be 
connected  in  at  (  —  C)  and  (  +  C)  as  shown 
just  under  the  audio  transformer  (AFT-2) 


in  Figs.  1—2.  This  will  save  enough  "B" 
battery  current  to  pay  its  way,  but  if  it 
is  not  desired  at  the  present  time,  the 
binding  posts  or  connections  (  —  C)  and 
(  +  C)  can  be  sort  circuits  as  indicated 
by  the  dotted  line  running  between  these 
two  connections.  The  "C"  battery  can 
be  the  smallest  type  of  "C"  battery  or 
else  can  be  a  small  flash  light  battery, 
either  giving  a  total  potential  of  4.5  volts 
on  the  grid  of  the  tube  (T3). 

Phonograph  Music  Directors 
Set  New  Standards 

T^HE  broadcasting  of  music  has  grown 
-*-  like  Topsy.  In  the  case  of  a  single 
artist  it  has  been  comparatively  easy  to 
indicate  .a  definite  position  before  the 
microphone  and  one  which  is  likely  to 
secure  the  best  results.  But  where 
several  artists  are  concerned  or  there  are 
a  number  of  musicians,  as  in  an  orchestra, 
the  problem  has  become  more  and  more 
complicated,  and  in  the  rapid  develop- 
ment of  broadcasting  it  has  been  one 
which  has  not  had  as  much  attention  in 
the  past  as  it  unquestionably  will  have  in 
the  future. 

However,  it  was  not  new  to  the  phono- 
graph people,  for  in  the  making  of  records 
they  have  been  experimenting  for  years 
in  the  proper  placing  of  the  instruments. 
An  orchestra  forming  in  a  broadcasting 
studio  as  a  rule  looks  like  an  orchestra 
playing  any  place  else,  but  in  a  phono- 
graph recording  laboratory,  it  is  a  most 
unusual  sight. 

The  man  playing  the  cello  may  be  on  a 
chair  with  legs  so  long  that  the  player's 
head  almost  touches  the  ceiling.  On  the 
other  hand,  the  tuba  player  may  almost 
be  sitting  on  the  floor.  Sometimes  the 
music  racks  are  suspended  from  the 
ceiling;  again  they  are  giraffe-like  affairs 
rising  from  the  floor. 


End  your  Radio  Troubles  for  30c  in  Stamps 

We  have  laid  aside  a  limited  number  of  back  issues  RADIO  AGE  for  your  use.  Below  are  listed  hookups 
to  be  found  in  these  issues.  Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired.  The  supply 
is  limited,  so  enrich  your  store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 


January,  1924 

— Tuning   Out  Interference — Wave  Traps — Eliminators 

— Filters. 

—A  Junior  Super- Heterodyne. 

— Push-Pull  Amplifier. 

— Rosenbloom  Circuit. 

March,  1924 

— An  Eight- Tube  Super-Heterodyne. 

—A  simple,  low  loss  tuner. 

— A  Tuned  Radio  Frequency  Amplifier. 

— Simp'e  Reflex  Set. 

April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated). 

—A  Ten-Dollar  Receiver. 

— Anti-Body  Capacity  Hookups. 

— Reflexing  the  Three-Circuit  Tuner. 

— Index  and  first  two  installments  of  Radio  Age  Data  Sheets. 

May,  1924 

—Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

—Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

— -Important   Factors   in    Constructing   a    Super-Heterodyne. 

—A  Universal  Amplifier. 

— A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 

— Radio  Age  Data  Sheets. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 

— Operating  Detector  Tube  by  Grid  Bias. 

— A  Three-Tube  Wizard  Circuit. 

— Data  Sheets. 

RADIO  AGE,  Inc. 


August,  1924 

— Breaking  Into  Radio  Without  a  Diagram. 

—The  English  4-Element  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 

September,  1924 

— How  Careful  Mounting  Will  Improve  Reception. 

— One  Tuning  Control  for  Hair's  Breadth  Selectivity. 

— Four  Pages  of  Real  Blueprints  of  a  New  Baby  Heterodyne 

and  an  Aperiodic  Variometer  Set. 
— Data  Sheets. 

October,  1924 

- — An  Easily  Made  Super-Het. 
— Two  Radio  and  Two  Audio  for  Clear  Tone. 
— A  Simple  Regenerative  Set. 
—The  Ultradyne  for  Real  DX. 

— Real  Blueprints  of   a    3-Tube    Neutrodyne    and    a    Midget 
Reflex  Set. 

November,  1924 

— Blueprints    of   a    Single   Tube    Loop    Set   and    a    Capacity 

Feedback    Receiver. 
— A  3-Tube  Low  Loss  Regenerator. 
— Mastering  the  3-Circuit  Tuner. 

December,  1924 

— Blueprints  of  a  New  8-Tube  Super-Heterodyne. 
— How  to  Make  a  Receiver  that  Minimizes  Static. 
— A  Trans- Atlantic  DX  Receiver. 

— How  to  Make  a  Home  Made  Battery  Charger  and  a  Loud 
Speaker  at  a  Small  Cost. 


January.  1925 

— A  Reflexed  Neutrodyne 
— A  Six  Tube  Super-Het. 
— An  Efficient  Portable  Set. 
— A  Tuned  Plate  Regenerator. 
— Making  a  Station-Finder. 

February,  1925 

— A  Sure  Shot  Super-Het. 

— A  Three  Circuit  Regenerator. 

— A  Real.  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex. 

March,  1925 

— A  Permanent  Super-Het. 
— A  5-Tube  R.  F.  Receiver. 
■ — How  to  Wind  Low  Loss  Coils. 
— A  Short  Wave  Receiver 

— Blue  Prints  of  a  Two-Tube  Ultra  Audion  and  a  Re- 
generative Reflex. 

Apr!!,  1925 

—A  3-Tube  Portable  Set 

— "B"  Voltage  from  the  A.  C.  Socket 

— An  Amplifier  for  the  3-Circuit  Tuner 

— Blueprints  of  a  Five-Tube  Radio  Frequency  Receiver 

May.  1925 

— A  "Quiet"  Regenerator. 

— A  Power  Supply  Receiver. 

— How  to  Make  a  Tube-Tester. 

— A  Unique  Super-Het  and  an  Improved  Reinaxt2. 

— A     Six    Tube    Portable    Rfceiver    Illustrated    with    Bin 


500  N.  Dearborn  St.,  Chicago 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


43 


'pHE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  is 
-L_  contributed  by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con 
tributors,  but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


BRIDES  and  static.  One  is  about  as 
hard  to  silence  as  the  other  in  the 
merry  month  of  June,  as  many  of 
our  Dial  Twisters  can  testify  after  sitting 
up  half  the  night  coyly  fishing  for  the 
elusive  DX  signals  while  the  Better 
Eight-Tenths  wonders  why  she,  of  all 
the  people  in  the  world,  should  have 
been  manacled  to  a  radio  maniac.  (We 
have  ofteli  wondered  what  the  feminine 
portion  of  the  Dial  Twister's  family 
thinks  ofthe  RADIO  AGE  button). 

Returning  from'  our  buttons  to  our 
muttons,  nothing  startling  has  been  dis- 
covered since  our  last  issue  of  RADIO 
AGE,  although  the  low-loss  campaign 
goes  ahead  rapidly.  The  outstanding 
feature  along  this  line  is  the  figure  8 
coil,  the  binocular  coil,  the  doughnut 
coil  and  other  coils  of  a  similar  type 
wherein  by  the  form  of  windings  the 
magnetic  field  of  the  coil  itself  is  kept 
within  its  own  bounds,  thus  cutting 
down  the  interstage  coupling  which  has 
been  the  bugbear  of  any  radio  fan  who 
ever  tried  his  hand  at  tuned  or  untuned 
radio  frequency  amplifiers. 

With  tnis  type  of  coil  and  the  proper 
design  of  the  set,  the  necessity  for 
neutralization  of  the  tubes  can  be  done 
away  with,  which  should  prove  a  boon 
to  all  radio  experimenters.  Let's  see 
which  one  of  our  Dial  Twisters  will  report 
the  best  results  with  the  new  type  of 
coils. 

They  say  musicians  have  no  home, 
but  since  radio  came  into  such  popu- 
larity, the  musician's  home  is  wherever 
he  parks  his  loudspeaker  (not  referring 
to  the  ladies,  however.)  Thomas  V. 
McLaughlin,  musical  director  of  the 
Hello  Jake  Company,  and  now  on  the 
road,  says  he  bought  his  first  copy  of 
RADIO  AGE  in  May,_  1923,  and  has 
not  missed  an  issue  since  that  time. 
Mr.  McLaughlin  made  the  Reinartz 
described  in  that  particular  month's 
RADIO  AGE  and  .later  added  two 
stages  of  audio.  Travelling  as  he  does, 
he  is  not  permitted  the  pleasure  of  an 
antenna,  so  at  night  in  the  hotel  room 
he  uses  the  radiator  for  an  antenna  and 
the  cold  water  faucet  for  the  ground. 
Once  he  forgot  to  connect  the  radiator 
while  at  Newcastle,  Pa.,  and  heard 
WOAW  in  spite  of  that  fact.  His  first 
set  was  made  on  the  side  of  a  prune  box, 
since  he  had  no  panel.  Despite  the  fact 
Mr.  McLaughlin  comes  from  Brooklyn, 
N.  Y.,  he  signs  off  with  the  following 
poetry: 

7  have  no  jive  tube  neutrodyne. 

Nor  an  eight  lube  super-het — 

But  RADIO  AGE,  from  page  to  Mge, 

Is  the  best  that  I've  seen  yet. 


CONTRIBUTOR. 
O.  C.  Wallace,  Jr.,  205  Lewis  Bldg.,  Montreal,  Canada. 

DIAL    TWISTERS 

Name  Address  City 

Thomas  V.  McLaughlin En  Route 

Lloyd  Stove Box  363 National  City,  Calif. 

Lloyd  H.  Shera ...San  Miguel,  Calif. 

Raymond  Breeden 1105  Orange,  N.  W Roanoke,  Va. 

J.  W.  Landon .....113  Scoville  Way Pittsburgh,  Pa. 

A.  P.  Smith R.  F.  D.  8 Bangor,  Me. 

W.  C.  Dukes,  Jr P.  O.  Box  449._ Mobile,  Ala. 

J.  W.  McCullah Soldiers  Home,  Calif. 

S.  Stansfield. 8035  Wilson  Ave Detroit,  Mich. 

Guy  Arthur P.  O.  Box  245. Massilon,  Ohio 

Fern  Frame .....768  Adams  St Gary,  Ind. 

W.  G.  McDonald 19  Marlborough  Apts Calgary,  Alta.,  Can. 

Jack  Warwick 217  St.  James  St Port  Arthur,  Ont.,  Can. 

Eugene  Arneson. 470  Exchange  St Kenosha,  Wise. 

F.  S.  Reed ...9123  Baltimore  Ave ...Chicago,  111. 

Harry  Emerick 311  Bedford  St... Johnstown,  Pa. 

T.  F.  Hyland...... R.  3.  Box  459 Sebastapool,  Calif 

Harry  T.  Adams 379  Going  St Pontiac,  Mich. 

Otto  C.  Glatt 87  Dunn  Ave...._ Toronto,  Can. 

Arthur  C.  Wilson ..557  West  1st  South Salt  Lake  City,  Utah 

J.  A.  McCormick 24  South  6th  St Fort  Dodge,  Iowa 

Paul  Nelson ...223  Du  Page  St Michigan  City,  Ind 

W.  G.  Mortimer 144  Central  Ave London,  Ont.,  Can. 

Eric  Gustafson 6  Bergen  Ave Jamaica,  L.  I.,  N.  Y. 

N.  J.  Hiscox Box  761 Brampton,  Ont.,  Can 

Clarence  Fairfield,  Jr 315  N.  F  St Hamilton,  Ohio 

Frank  J.  Sanzone 244  Hull  St Brooklyn,  N.  Y. 

R.  A.  DeVries 114  Eighth  Ave New  York  City,  N.  Y. 

J.  J.  Griffiths 2782  Rouen  St..... Montreal,  Can. 

Harry  S.  Chasen.... 1724  N.  Payson  St Baltimore,  Md. 

Charles  P.  Smith 129  E.  Pomona  Terrace  ..Germantown,  Pa. 

Wm.  A.  Swicky 1045  Maple  Ave Los  Angeles,  Calif. 


KDKA.  KOA,  WCX,  WBAB.  WDAF.  TVEBH.  WFAA. 
WGN,  WGY.  WHAA.  WHO.  WLS.  UOAI,  WOC,  WQJ, 
WSAI,  WTAM.  WTAS,  WCOO.  WLW,  CFCN.  CFDC, 
CFRC.  and  a  lone  list  of  others  which  we  think  would  stagger 
our  linotype  operators. 


Harry  S.  Chasen,  1724  N.  Payson 
St.,  Baltimore,  Md.  sends  in  a  sketch 
of  what  he  calls  the  "Bearcat  Roamer" 
consisting  of  a  tapped  secondary  coil 
and  condenser,  untuned  primary,  and  a 
variometer  in  the  plate  circuit,  a  typical 
regenerative  circuit,  with  which  he  is 
having  great  success.  He  is  using  all 
low-loss  parts  and  believes  much  of  his 
success  can   be  attributed  to  that  fact. 


Lloyd  H.  Shera,  San  Miguel,  Cali- 
fornia, using  a  two  tube  reflex,  is  bring- 
ing in  the  East  Coast  and  Canada  quite 
well.     Some  of  his  stations  shown   are: 


John  James  Griffiths,  2782  Rouen  St., 
Montreal,  Canada,  using  a  three  circuit 
set  and  the  "peanut"  tubes  which  are 
available  in  that  country,  sends  in  a 
good  list  of  stations  which  entitles  him 
to   the   button. 


Here's  a   most  interesting  letter  from 


Robert  A.  DeVries,  114  Eighth  Ave., 
New  York  City,  who  says:  "I  am 
writing  to  give  my  views  on  your  in- 
teresting magazine  and  also  to  qualify 
for  a  Dial  Twister's  button.  I've  been 
buying  your  magazine  for  over  two  years, 
when  I  used  to  have  to  wait  until  the 
middle  of  the  month  to  get  it,  and  then 
I  used  to  enjoy  it  more  than  now.  Your 
magazine  was  then  devoted  to  radio 
beginners,  enthusiasts  and  experimenters. 
Your  magazine  was  then  only  a  few 
pages  but  in  those  few  pages  was  printed 
matter  interesting  enough  for  the  type 
of  radio  fans  I've  mentioned,  and  in- 
teresting enough  to  make  it  grow  to 
its  present  proportions.  Here's  what  I 
am  getting  at.  You  are  now  printing 
radio  stories  and  elaborate  interviews 
of  announcers,  etc.;  reach  the  set-owner 
by  telling  him  what  the  other  fellow  is 
doing:  that  is  why  Dial  Twisters  and 
their  hook-ups  are  the  most  interesting 
(Turn  the  page) 


44 


RADIO  AGE  for  June,  1925 


WONDER 

\NHEN  TH' 
DURN ED 

I  S  OON  K/ 


z> 


The  Magazine  of  the  Hour 

country.  Let  the  Dial  Twisters  enlarge 
their  territory.  Have  been  building  hook- 
ups for  many  years  and  never  found  so 
very  much  new.  I  use  an  Armstrong 
three  circuit  with  a  stage  of  radio  ahead. 
It  will  bring  in  anything  on  a  75  foot 
aerial  that  a  super  will  do  on  a  loop.  I 
have  logged  PWX,  2LO,  CKY,  CNRO, 
KFI.  Why  bother  about  a  portable  set? 
Just  use  dry  cell  tubes  if  you  are  not 
intending  traveling  by  auto.  The  old 
three  circuit  with  a  wire  thrown  up  in  a 
tree  will  go  it  o.  k.     So  what's  left?" 


part  of  the  magazine.  How  about  a 
column  devoted  to  queer  and  unusual 
things  that  happen  in  radio,  contributed 
by  the  readers?  For  instance,  I  have 
push-pull  amplifiers  in  my  set  and  when 
I  removed  the  loud  speaker  plug  I  lifted 
the  lid  on  the  cabinet  and  could  hear 
music  from  one  of  our  powerful  locals. 
Also,  Saturday,  February  7,  Stations 
KFI,  KOA  and  WMBF  were  broad- 
casting the  song  'My  Best  Girl'  at  the 
same  time.  Isn't  that  unusual?  My 
set  is  a  three-circuit  tuner  built  from 
the_  March  issue  of  RADIO  AGE,  and 
to  it  I  have  added  one  stage  of  r.  f. 
I  am  sending  a  list  of  some  of  the  stations 
over   1,000  miles  which   I  have  logged." 


N.  J.  Hiscox,  Box  761,  Brampton, 
Ontario,  Canada,  tells  us  he  is  using  a 
honeycomb  coil  set  with  detector  and 
one  stage  of  audio  which  is  now  in  its 
fifth  year,  and  like  Johnny  Walker, 
still  going  strong.  It  is  a  home-made 
set  and  was  the  first  set  in  his  vicinity. 


Eric  Gustafson,  6  Bergen  Ave.,  Jamaica, 
N.  Y.,  has  found  that  by  putting  a 
fixed  capacity  from  the  upper  phone 
binding  post  to  the  negative  lead  of  the 
A  battery,  he  gets  much  better  results. 
This  is  what  is  known  as  "by-passing" 
and  is  one  of  the  kinks  that  every  dyed- 
in-the-wool  experimenter  does  almost 
unconsciously.  If  more  fans  did  like 
Mr.  Gustafson,  the  "What's  wrong  with 
my  set"  type  of  letter  'would  not  be  so 
abundant    around    these    parts. 

O.  C.  Wallace,  Jr.,  205  Lewis  Bldg., 
Montreal,  Que.,  Canada,  sends  in  a  neat 
little  design  of  one  stage  of  radio  fre- 
quency amplification  to  be  added  to  the 
conventional  Reinartz  tuner.  He  says 
it  has  increased  his  range  and  selectivity. 
He  uses  a  separate  A  and  B  battery.  His 
r.  f.  coil  is  wound  on  a  3)^  inch  tube. 
The  aperiodic  primary  consists  of  ten 
turns  and  is  spaced  about  a  quarter-of-an- 
inch  from  the  secondary,  which  consists 


of  42  turns.  The  diagram  herewith  is 
being  amended  so  that  you  do  not  have 
to  have  separate  A  and  B  batteries  but 
can  add  your  r.  f.  stage  to  your  present 
Reinartz.  The  condenser  used  across  the 
secondary  is  a  .0005  mfd. 

Arthur  O.  Wilson,  557  West  First 
South  St.,  Salt  Lake  City,  Utah,  says 
his  second  attempt  at  set  building  was 
the  ultra- audion,  blueprinted  in  the 
March  RADIO  AGE,  and  he  is  now 
starting  on  the  one  described  by  Mr. 
Sonn  in  the  April  number.  He  found 
best  results  with  a  120  turn  tapped  astatic 
wound  coil,  which  type  of  winding  he 
will  be  glad  to  describe  to  any  one  who 
writes  him.  His  list  of  stations  is  not 
only  a  testimonial  for  the  ultra-audion ; 
but  gets  him  the   D.   T.   button. 

Another  ultra-audion  fan  is  found  in 
Otto  C.  Glatt.  87  Dunn  Ave.,  Toronto, 
Canada  (goodness,  how  these  Canadians 
are  coming  to  the  front  in  radio).  He  is 
an  inveterate  RADIO  AGE  fan  and  asks 
us  to  fade,  if  we  can,  his  record  on  the 
night  of  March  7th,  of  WMBF,  KOA, 
6KW,  KGO,  KHJ,  KFI,  KNX,  all  of 
which  have  been  verified. 


T.  F.  Hyland,  R.  3,  Box  459,  Sebasta- 
pool,  Calif.,  built  up  a  tuned  plate  regen- 
erator as  described  in  the  January 
RADIO  AGE,  on  which  he  gets  as  far 
East  as  KDKA  and  as  far  North  as  Cal- 
gary. He  thinks  this  is  a  fine  set  for  the 
novice  to  build. 


Using  a  one  tube  set,  Harry  Emerick, 
311  Bedford  St.,  Johnstown,  Pa.,  drags 
them  in  from  CNRO  to  PWX  and  from 
WBZ  to  KGO.  He  declares  he  is  an 
avid  RADIO  AGE  reader  and  especially 
delights  in  turning  to  this  portion  of  the 
magazine  on  its  arrival  each  month. 


F.  S.  Reed,  9123  Baltimore  Ave., 
Chicago,  111.,  comes  to  bat  with  this  one: 
"Let's  rule  out  the  U.  S.  as  far  as  signals 
are  concerned.  Most  any  good  set  will 
bring  in  the  worth-while  stations  in  this 


Here's  a  crystal  hound;  that  is,  he 
used  to  be.  Raymond  Breeden,  1105 
Orange  Ave.,  N.  W.  Roanoke,  Va.,  who 
tells  us  his  first  experience  in  picking  up 
KDKA,  WGY  and  WEAF;  later  this 
was  increased  to  WEBJ,  WJZ,  WOR, 
WOC,  WLW,  his  maximum  distance 
being  somewhat  over  600  miles  on  a 
crystal.  Then  he  went  in  for  a  single 
tube  set  and  got  all  of  the  old  stations  he 
had  heard  on  crystal  and  a  new  bunch  in 
addition,  which  included  KGO,  CNRO, 
CKAC.  Raymond  is  only  a  youngster 
in  years,  but  he  turns  them  out  like  a 
veteran  at  logging. 

Lloyd  Stove,  Box  363,  National  City, 
Calif.,  with  a  super,  using  loop  and 
ground,  reports  the  Canadians,  Hawaii- 
ans,  Mexicans  and  our  friend  2-LO. 
He  tuned  in  115  stations  with  an  average 
mileage  per  station  of  1315  miles.  All 
except  London  were  heard  on  the  loud 
speaker. 

Since  Mr.  Stove  is  located  in 
California,  the  full  list  of  his  stations 
might  be  of  interest  to  our  readers.  The 
list  follows: 

KFNV,  KOB.  KDYL,  KFPT,  KFI,.  KFHA.  CZF,  KFATJ. 
KFUM.  KFAJ,  KFEL,  KLZ.  KOA.  KFCF.  KGW. 
KFAE.  KFIQ.  KTJOM.  WCAT.  KFOA,  KFQX.  KHQ' 
KFHR.  KJR.  WOAI,  WCAR.  WBAP.  KFKX,  W1AD. 
WFAA,  KFRU.  CKCD,  KFKB,  KSAO,  CHCM. 
CFAl,,  DFCN.  CKCX.  CXRC.  KFAB.  WEaY. 
KFKU,  WOAW,  WAAW,  KFNF.  KFMQ.  WDAP.  WEB, 
KTHS.  WGAQ,  KFDM.  WHO.  WOI.  CYL.  CVB,  CYX, 
WOS.  WCAL.  KFMX.  WCCO.  WSUI.  KSD.  KFUO.  WMC. 
WSAB.  CKY,  CN'RW,  WJJD.  WHA,  WEBW.  WLBL. 
WTAS,  WCEE.WHAD,  KYW.  WEBH.  WGN,  WGN,  WLS. 
WMAQ,  WQJ.  WBCN,  WCBD,  WHAS.  WLW,  WSAI. 
WGST.  WSB.  WREO.  WBAV.  WEAO,  WCX,  WEAR. 
WTAM.  WCAE.  KQV.  KDKA,  WGR.  WMAK,  WCAP. 
WMBF.  KGU.  WCAU.  WFT.  PWX,  WAHG.  WEAF.  WJZ. 
WNYC.  WGY.  WHAZ,  WBZ,  WEEI.  and  last  but  not  least 
2-LO,  London;  (Verifiedbir  the  British  Broadcasting  Co.) 


Then  from  south  of  the  Smith  and 
Wesson  line  comes  a  letter  from  W.  C. 
Dukes,  Jr.,  P.  O.  Box  449,  Mobile,  Ala- 
bama, telling  us  of  his  work  with  a  three 
circuit  regenerative  set  using  WD- 11 
tubes.  On  headset  he  has  brought  in  the 
East  and  West  coasts,  Canadian  sta- 
tions, two  of  the  Mexican  stations  and 
Havana,  Cuba.  A  short  list  of  stations 
follows: 

WTAS  KDKA  KFDM,  KFTX.  WBBM,  WKAA,  WORD. 
KPKB  KFMQ.  WSAI.  WEBH,  WHB,  KTHS.  WGY. 
WMBF  WOAI.  WOS.  WOAW.  KSD.  KYW.  WBAP. 
WMC,  WQJ.  WSB.  KFRU,  WMH.  WLS.  WFAA.  KFI, 
WHO.    WDAF. 


Al  P.  Smith,  R.  F.  D.  No.  8,  Bangor, 
Me.,  gives  a  list  of  stations  heard,  one 
of  which  was  during  the  tests,  being 
5NO  at  Newcastle,  England.  He  uses 
the  dry  cell  type  of  tubes  and  has  a 
neutralized  stage  of  r.  f.  detector  regener- 
ative and  one  stage  of  audio.  He  has 
also  built  a  three  circuit  receiver  with 
three  stage  resistance  coupling,  which 
he  used  for  short  wave  work.  The  list 
follows: 

WEEI.  WNAC.  WMAF.  GWT.  WBZ.  KYW,  WDBH. 
WTAS,  WON.  WEBH.  WREO.  WGR.  WHN.  WEAF. 
WJY,  WJZ,  WAHG.  WGY.  WHAS.  WTAM.  KDKA. 
WIP.  WJAR.  WCAP,  WF.G.  CHAC,  CFCF,  CHYC.  CKAC, 
WKAQ,  PWX,  WMC,  WCBD.  WQAM.  WDAE,  WOC. 
WHAS,     KFKX. 


S.  Stansfield,  8035  Wilson  Ave., 
Detroit,  Mich.,  who  is  a  faithful  follower 
of  RADIO  AGE  blueprints  and  diagrams, 
made  up  a  Reinartz  with  two  stages  of 
audio,     using    WD- 11     tubes.       Stations 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


45 


heard  by  him,  mileage  greater  than  500, 
follow: 

WPG.  KFNF.  WBZ.  KFKB,  KFKX,  WOAW.  WEAF, 
WGY  WEEI.  KFEZ,  WDAP,  WCCO,  WHB,  WEAJ. 
WAHG.    WHN,    KOA.    WCAL.  WMAK. 


Guy  Arthur,  P.  O.  Box  245,  Massillon, 
Ohio,  a  constant  reader  of  RADIO  AGE, 
spends  most  of  his  spare  time  experi- 
menting with  circuits  furnished  by  this 
magazine.  He  relies  on  his  "squealer" — 
a  three  tube  regenerative,  for  distance. 
During  the  tests  he  picked  up  2LO.  He 
now  gets  'em  from  coast  to  coast,  and  is 
now  interested  in  a  reflex  set  using  two 
tubes. 


Jack  Warwick,  217  St.  James  St., 
Port  Arthur,  Ont.,  Can.,  writes  as 
follows:  "I  have  studied  with  great 
interest  contributions  under  'Pickups 
and  Hookups,'  and  thought  perhaps 
some  of  the  readers  might  be  interested 
in  my  experiences.  During  construction 
lost  the  diagram  and  had  to  finish  it 
the  best  I  could,  with  good  results.  As 
near  as  I  can  remember,  it  is  a  regenera- 
tive (that's  as  much  as  I  know  about 
radio,  Mr.  Editor);  couldn't  tell  you  the 
'diff'  between  or  names  of  any  hookups. 
The  equipment  for  my  set  is  2  tubes 
(Myers)  six  volt  detector  tube,  2  1-2 
volt  amplifier  tube,  Crosley  vari-coil, 
with  10  taps;  23  plate  aluminum  con- 
denser, couple  of  6  ohm  rheostats,  etc., 
with  a  125  foot  single  strand  aerial. 
Here  are  some  of  the  stations  I  pick  up: 

CKAC.  CNRO.  CFCA.  CXRW,  CNRT.  KDKA.  KFI, 
KFKX.  KFNF,  KFRU.  WOAW.  WDAF.  WOO,  WHO. 
WSUI  WEAF.  WEEI,  WBZ,  WTAS,  WTAM,  WOBD, 
WCCO,  WCAE,  WGN.  WCY.  WGR,  WFAA,  WCX.  WIP. 
WLS.  WOS,  WREO.  WCAL,  WQJ,  WSAI,  WSB.  WWJ, 
WMC. 


Harry  T.  Adams,  379  Going  St.,  Pon- 
tiac,  Mich.,  tells  us  he  made  a  three  tube 
neutrodyne  from  the  blueprints  in  the 
October,  1924,  issue  of  RADIO  AGE 
and  has  since  added  a  pair  of  push-pull 
transformers.  He  now  gets  both  of  the 
coasts  most  of  the  time  on  the  loud 
speaker,  getting  good  quality  and  selec- 
tivity. 

W.  G.  McDonald,  19  Marlborough 
Apts.,  Calgary,  Alberta,  Canada,  has  the 
following  interesting  letter  for  this  sec- 
tion: 

"I  have  been  a  reader  of  your  excellent 
magazine  for  some  time,  and  admire  the 
way  in  which  it  is  gotten  up.  The 
department  to  which  this  letter  is  ad- 
dressed is  the  best  of  the  lot,  and  I 
always  read  it  the  first  of  any.  The 
communications  from  the  DX  fans  are 
always  interesting  in  their  various  view- 
points and  contentions.  I  would  like  to 
tell  you  about  the  results  which  I  have 
obtained  with  the  old  'dumb-bell'  single 
circuit,  made  up  by  myself  with  only 
middling  quality  parts,  using  that  ex- 
cellent little  tube,  the  Canadian  peanut, 
which  is  really  the  W.  E.  'N'  Tube,  and 
which  you  Americans  are  very  unlucky, 
in  my  estimation,  to  be  unable  to  procure. 

"I  have  used  all  makes  of  American, 
French  and  English  tubes  besides  our 
various  Canadian  ones,  and  considering 
the  dry-cell  A  Battery,  our  little  peanut 
has  them  all  beaten  a  mile.  My  aerial 
is  two  wires,  65  feet  long  and  20  feet 
high.  We  have  in  this  city  seven  active 
stations,  six  of  whom  never  heard  of  a 
sharply  tuned  transmitter,  and  having 
outputs  at  the  present  time  which  I 
believe  are  as  strong  or  stronger  than 
your  best  stations. 

"That  is  one  fault  of  Canadian  broad- 
casting, and  when  it  takes  receivers  of 
the  super  or  neutrodyne  class  of  excellent 
construction  to  get  rid  of  locals,  you  can 
understand    under    what    difficulties    my 


0.  C.  Wallace's  contribution  for  the  Reinartz/an  who  desires  to  add  a  stage  of  radio  frequency  amplification, 
ahead  of  the  present  detector  in  the  Reinartz  circuit.  LI  is  an  inductance  of  10  turns  wound  on  the  lower  end  of  an. 
insulating  tube  3  1-2  inches  in  diameter.  This  can  be  wound  with  No.  20  DCC.  L  2  is  the  secondary  inductance 
consisting  of  42  turns  of  the  same  sized  wire.  This  winding  is  started  about  a  quarter  of  an  inch  away  from  the 
primary.  L  3  is  the  primary  'be  sure  it  is  thoroughly  isolated  from  the  other  parts  of  the  old  Reinartz  tuner)  of 
your  present  tuner.  It  now  becomes  the  primary  of  the  radio  frequency  transformer.  The  condenser  shown  is  a. 
.0005  mfd  variable,  any  good  make.  The  dotted  line  shows  the  connection  of  one  end  of  the  old  primary  to  the 
plate  of  the  new  r.  f.  unit:  the  other  end  of  L  3  going  to  the  positive  of  the  B  battery.  Wires  can  be  run  from  -A. 
and  plus  A  to  the  usual  binding  posts  on  your  set  so  a  separate  A  and  B  battery  will  not  be  required.  The  slator 
of  the  variable  condenser  goes  to  the  grid  and  the  rotor  to  the  filament  line. 


little  single  circuit  is  working.  The  list 
of  stations  I  have  received  over  500  miles 
is  as  follows: 

KDKA.  KDYL.  KDZB,  KFAF.  KFAW,  KFBK,  KFEC. 
KFEL.  KFI,  KFJM,  KFKA.  KFKB.  KFKX.  KGO.  KH., 
KJS.  KLX,  KLZ.  KPO.  KSD.  KUO.  KWG,  KWH,  KYW. 
WAAW.  WBAD.  WBAP.  WBZ.  WCAE,  WCAL,  WCAP. 
WCBD.  WDAF.  WEAF.  WEBH.  WFAA.  WGN,  WGR. 
WGY,  WHA.  WHAA.  WHAS.  WHB,  WHO.  WJY.  WJZ. 
WLW.  WMAC.  WOAW,  WOI  ,  WOI,  WOR,  WOS,  WRC. 
WSAI,  WTAM,  WTAS,  CJCE,  CKCD.  CKY. 

"I  have  a  total  of  104  stations  in  my 
log  book,  but  some  of  them  are  last 
year's  reception,  and  a  great  number 
under  500  miles. 

"Besides  these  BCL  stations,  I  have 
received  amateurs  in  almost  every  dis- 
trict of  U.  S.  and  Canada;  ships  in  the 
Atlantic,  and  off  the  coast  of  Asia. 
Altogether,  I  think  that  the  single  cir- 
cuifis  hard  to  beat  where  one  does  not 
get  QRM  from  broadcasters,  and  does 
not  cause  it  by  unwise  use  of  the  tickler. 
Considering  the  situation  of  Canada  with 
regard  to  the  U.  S.  stations,  I  think  we 
Canadians  are  doing  very  well.  Would 
like  to  hear  from  some  more  Canucks 
through  the  pages  of  RADIO  AGE. 
Canadian  4-1 M   signing  off." 


The  transmitter  used  at  Bellevue  em- 
ployed less  than  two  kilowatts,  while 
the  antenna  was  of  the  vertical  cage 
type  with  a  four  wire  counterpoise.  It 
is  of  incidental  interest  that  during  the 
two  way  conversation  it  was  morning  in 
Australia  while  it  was  midnight  at  Belle- 
vue. 

While  the  above  feat  was  accomplished 
by  the  use  of  2,000  watts  in  the  antenna, 
and  American  amateurs  have  com- 
municated before  with  much  less  power, 
nevertheless,  this  fact  does  not  detract 
from  the  importance  of  the  achievement 
on  behalf  of  the  Navy. 


Some  of  our  readers  who  belong  to  the 
dot  and  dash  fraternity  might  be  in- 
terested in  a  new  ecord  made  by  the 
Naval  Radio  Laboratory  at  Bellevue, 
D.  C,  in  establishing  two  way  com- 
munication with  Australia  on  twenty 
meters  on  the  night  of  April  20. 

Around  midnight,  according  to  reports 
which  have  reached  RADIO  AGE,  the 
operator  on  watch  at  Bellevue  heard  the 
Australian  station  calling  England.  He 
immediately  broke  in  and  called  the 
Australian.  The  two  stations  then  com- 
municated with  each  other  foi  more  than 
thirty  minutes.  There  was  a  particular 
absence  of  static  and  other  forms  of  in- 
terference. 

Bellevue  Laboratory  has  been  making 
some  rather  remarkable  distance  feats 
on  short  waves.  Australia  has  been  copied 
before  at  Bellevue,  but  the  first  time  two 
way  communication  was  established  was 
on  April  20. 


Loop  Record 

E.  H.  Scott,  of  Chicago,  but  now  at 
Tasman,  Nelson,  New  Zealand,  has 
written  RADIO  AGE  telling  of_  his 
reception  of  many  American  stations, 
nineteen  in  all,  among  which  some  of 
the  Chicago  stations  figure  prominently. 

To  make  certain  of  his  reception  Mr. 
Scott  wrote  all  the  stations  and  asked 
them  to  send  their  verifications  to  the 
RADIO  AGE,  and  to  date  quite  a  number 
have   been   received. 

Chicago  Stations  heard  by  Mr.  Scott 
were:  WEBH,  WGN,  WQJ,  WJJD, 
KYW.  He  also  heard  KGO,  KNX, 
KFI,  WFAA,  WDAF,  KPO,  KOA, 
WCBD,   CFCN  and  KHJ. 


World's  "Record" 

The  Editor  of  The  Dominion,  a  news- 
paper at  Wellington,  gives  Mr.  Scott 
credit  for  a  world's  record  for  reception 
on  a  loop.  He  is  using  an  eight  tube 
super.  The  time  difference  between 
Chicago  and  New  Zealand  is  seventeen 
and  a  half  hours,  New  Zealand  being 
ahead  of  Chicago  time. 

The  above  seems  to  be  a  pretty  good 
test  for  a  super  using  a  loop,  since  most 
of  the  distances  are  in  excess  of  five 
thousand  miles  while  the  maximum  runs 
up  to  8,000  miles. 


46  RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Standard    Radio   Receivers 

'  Recently  RADIO  AGE  inaugurated  a  new  department  called  "Know  Before 
You  Buy,"  to  serve  as  a  guide  to  the  prospective  radio  purchaser  in  deciding  on  the 
receiver  best  suited  to  his  individual  needs.  Fans  throughout  the  country  have  shown 
an  instantaneous  response  to  this  new  feature,  and  accordingly  it  is  continued  and 
will  be  a  feature  of  all  forthcoming  numbers  of  RADIO  ACE.  Readers  are  invited 
to  write  us  concerning  the  sets  in  which  they  are  interested,  and  manufacturers  also 
are  asked  to  send  us  material  describing  their  sets. 


High  or  Low  Waves,  Here's  a  Re- 
ceiver That  Brings  'Em  All  In 

TF  AN  extended  use  of  lower  wave- 
-*-  lengths  in  broadcasting  is  to  be,  as 
many  leading  radio  engineers  believe, 
the  answer  to  the  problem  of  providing 
wavelength  designations  not  only  for 
the  broadcasters  already  operating  but 
also  for  broadcasters  who  have  asked  for 
licenses  and  are  awaiting  allocations, 
here  is  a  set  with  which  the  fan  may  tune 
in  on  any  of  wave  frequencies,  from 
forty  meters  on  up  to  555  meters  or  more, 
by  means  of  a  very  ingenious  but  simple 
adjustment  of  transformers. 

One  of  the  chief  drawbacks  to  universal 
broadcasting  on  low  wave-lengths  is  the 
fact  that  millions  of  sets  now  in  use  will 
not  tune  in  carrier  waves  below  200 
meters  or  above  600  meters. 

Stations  such  as  KDKA  and  WGY  are 
taking  advantage  of  the  extraordinary 
qualities  of  extremely  low  wavelengths 
to  transmit  programs  over  tremendous 
distances  in  the  daytime.  These  low 
waves  are  picked  up  by  stations  in  other 
countries  and  rebroadcast.  With  the 
set  described  herein,  it  will  not  be  neces- 
sary to  hear  these  programs  over  the 
repeat  stations  but  the  original  low  wave 
transmitters  may  be  tuned  in  and  lis- 
tened to  with  equal  ease.  In  fact",  this 
set  has  demonstrated  that  the  extremely 
low  wavelengths  carry  programs  better 
in  every  respect  than  do  the  customary 
carrier    waves,    and    an    interesting    and 


rapidly  growing  field  of  low  wavelength 
entertainment  is  opening  up  for  and 
awaiting  the  audience  that  can  tune  it  in. 
The  accompanying  illustration  reveals 
how  the  Washburn  Interchangeable  Five 
turns  the  trick  and  also  how  easily  and 
quickly  the  set  may  be  adapted  to  receive 
carrier  waves  from  40  meters  on  up.  The 
receiver  employs  five  tubes,  utilizing 
a  radio  frequency  circuit  and  is  con- 
trolled b}T  three  dials.  The  transform- 
ers are  of  a  rigid  type,  air  core,  low 
loss  and  built  to  stand  rough  usage.  They 
are  mounted  on  special  bakelite  adapters 
that  will  fit  into  standard  tube  sockets, 
so  that  they  are  interchanged  exactly 
as  standard  base  tubes  are  interchanged 
and  with  the  same  ease  and  quickness. 
The    picture    shows    three    sets    of    the 


interchangeable  transformer  coils.  When 
Set  No.  1  is  in  position,  waves  from  224 
to  555  meters  may  be  tuned  in.  The 
intermediate  set  of  transformer  coils 
permits  of  tuning  in  carrier  waves  be- 
tween 170  and  235  meters.  The  low  set 
will,  tune  in  carrier  waves  from  40  to  160. 
It  will  be  seen  that  the  three  sets  have 
overlapping  capacities.  Special  addi- 
tional coils  render  possible  the  reception 
of  wavelengths  indefinitely  upward. 

The  Washburn  Interchangeable  Five 
recently  was  subjected  to  a  series  of 
rigid  tests  by  the  Jefferson  Electric 
Laboratories,  Chicago,  and  as  a  result 
given  the  highest  commendation. 

The  Washburn  Interchangeable  Five 
is  manufactured  by  the  Washburn 
Burner  Corporation  of  Kokomo,  Indiana. 


The  Freshman  Masterpiece 
Unique  Circuit 

The  Freshman  "Masterpiece"  is  a 
five  tube  tuned  radio  frequency  receiver, 
built  of  the  finest  low  loss  material  and 
priced  to  fit  the  layman's  purse,  manu- 
factured by  Chas.  Freshman  Co.,  Inc., 
New  York  City. 

The  Freshman  Masterpiece  utilizes  a 
circuit  designed  by  A.  W.  Franklin,  a 
well  known  radio  and  electrical  en- 
gineer. This  system  totally  eliminates 
oscillations  by  the  use  of  scientifically 
designed  radio  frequency  units  in  which 
low  loss  coils  of  special  construction  are 
employed. 

The  set  is  known  throughout  the  world 
for  its  ability  to  receive  those  far-off 
stations.  It  is  mounted  in  a  genuine  solid 
mahogany  cabinet,  and  the  price,  with- 
out   accessories,    is    $60.00. 

Thousands  of  communications  from 
users  of  the  Freshman  Masterpiece 
testify  to  the  Chas.  Freshman  Com- 
pany's   claim    that    these    sets    furnish 


selectivity,  volume,  ease  of  operation 
and  perfect  tone  qualities. 

Many  distance  records  have  been 
achieved  with  the  Freshman  Masterpiece, 
bringing  in  distant  broadcasting  stations 
with  local  volume. 

There  are  but  three  tuning  controls, 
each  of  which  is  set  at  approximately 
the  same  dial  reading;  therefore,  once  a 
station  is  tuned  in,  one  can  rely  upon 
getting  the  same  station  each  time  at 
the  same  dial  setting. 


The  Grebe  Synchrophase 

and  the 

' '  Thermiodyne" 

Described  on  page  61 


RADIO  AGE  for  June,  1925 


I 

9 

v^ 

Plate  exclusive* 
ly  an  Ultra- 

Lowloss  feature 

A  guarantee  of 
satisfaction  and 
Lacault  design 

JLs  positive  as 

ator  ^ 


* 


TlLTRTt-VSRHISR 

TUNING       CONTROL 

Simplifies  radio  tuning.  Pencil-record  a  station  on 
the  dial — thereafter,  simply  turn  the  finder  to  your 
pencil  mark  to  get  that  station  instantly.  Easy — 
quick  to  mount.  Eliminates  fumbling,  guessing. 
Furnished  clockwise  or  anti-clockwise  in  gold  or 
silver  finish.     Gear  ratio  20  to  1. 

Silver  $2.50        Gold  $3.50 


CET   Big  Ben   at  seven  and  at  seven   o'clock  you're  bound   to   gel   the 
alarm. 

Just  so,  the  Ultra-Lowloss  condenser  can  be  set  at  any  wave-length-  the 
corresponding  station  will  come  in  clear  and  sharp.  You  know  instantly 
where  to  turn,  once  a  station  of  known  wavelength  is  located.  Makes 
tuning  easy — direct — positive.  Special  Cutlass  Stator  Plates  spread  wave- 
lengths evenly  over  a  100  degree  scale  dial  so  that  each  degree  represents 
approximately  Zyi  meters. 

Ultra-Lowloss  condensers  are  designed  by  R.  E.  Lacault,  originator  of  the 
famous  Ultradyne  Receivers,  and  built  upon  scientific  principles  which 
overcome  losses  usually  experienced  in  other  condensers. 

At  your  dealer's,  otherwise  send  purchase  price  and  you  will  be  supplied 
postpaid. 

Design  of  lowloss  coils  furnished  free  •with  each  condenser  for  amateur  and  broad- 
cast 'wavelengths  showing  'which  will  function  most  efficiently  with  the  condenser. 

To  Manufacturers  Who  Wish  to  Improve  Their  Sets 

Mr.  Lacault  will  gladly  consult  with  any  manufacturer  regarding  the  application 
of  this  condenser  to  his  circuit  for  obtaining  best  possible  efficiency. 

ULTRTHiOTULOBS 

CONDENSER 

PHENIX  RADIO  CORPOMTION,11^^2^ st 


*     Tested  and  Approved  by  RADIO  AGE     * 


48 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Free   Subscriptions 

to  Radio  Age  for 

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tribution for  the  July  RADIO  AGE. 

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Radio  Discovers  a  New 
Civilization 

(  Continued  from  page  28) 
large  and  small,  dotted  the  tops  of  the 
'mesas'.  Archeological  surveys  indicate 
they  were  excavated  by  the  original 
builders  to  a  depth  of  three  to  five  feet 
and  were  surrounded  by  sleeping  chambers 
and  granaries.  The  roofs  originally  were 
of  the  tepee  style,  willow  or  oak  beams 
being  fastened  together  by  a  wattling  or 
weaving  of  pliable  branches.  The  outer 
surface  was  then  plastered  with  adobe, 
and  over  this  thin  slabs  of  rock  were  laid. 
Walls  were  of  stone. 

Habits  of  the  Lost  "Race" 

T^NTRANCE  was  through  a  steep  de- 
*—*  cline  or  tunnel,  sufficiently  large  to 
accommodate  only  one  body  at  a  time. 
Doors  were  large,  close-fitting  slabs  of 
rock.  Fires  were  built  in  the  exact  center 
of  the  large  or  main  room  according  to 
mute  evidences,  and  a  circular  opening 
at  the  apex  of  the  sharply  sloping  roof 
permitted  the  escape  of  smoke  and 
furnished  ventilation." 

One  pithouse  revealed  a  handsome 
bowl  showing  a  design  of  four  stars  or 
equilateral  crosses,  a  symbol  still  found 
among  Pueblo  and  Navajo  Indians  and 
said  to  designate  the  evening  star.  This 
specimen  was  accompanied  by  a  badly 
decomposed  skeleton.  Beneath  the  well- 
packed  adobe  floor  of  another  prehistoric 
dwelling,  excavators  found  a  virtually 
perfect  skeleton  of  a  woman  between  35 
and  40  years  of  age  and  approximately 
five  feet  ten  inches  in  height. 

"She  was  buried  in  a  most  unusual 
position,"  Smith  observed.  "The  right 
cheek  was  resting  on  the  right  hand  and 
the  left  arm  was  placed  across  the  breast. 
The  knees  were  flexed.  Beside  the 
skeleton  was  an  unusually  elaborate 
gray  bowl  decorated  with  the  designs  of 
conventionalized  butterflies.  Close  at 
hand  we  found  a  complete  pottery  face 
— that  of  a  doll,  which  was  supported 
originally  on  a  body  consisting  of  a 
corncob." 

Excavators  are  agreed  that  the  final 
stage  of  development  of  this  prehistoric 
civilization  was  exemplified  by  an  ancient 
"apartment"  house — thirty-nine  rooms 
of  which  already  have  been  opened — and 
two  monumental  watch  towers,  now  in 
ruins.  These  were  found  on  top  a  pre- 
cipitous table  rock,  overlooking  a  valley 
1600  feet  below,  in  the  San  Juan  National 
forest  in   southern   Colorado. 

The  next  step  is  one  of  mystery,  Smith 
points  out.  Was  this  prehistoric  race 
overpowered  and  completely  obliterated 
or  was  it  ravaged  by  disease? 

Smith's  description  to  KOA's  inter- 
national audience  was  accompanied  by 
incidental  Indian  music  by  native  tribes- 
men, including  Chief  Evergreen  Tree  of 
the  Cochiti  tribe.  The  subject  was  pre- 
sented in  three  sections  as  follows: 
"Legends  of  a  Lost  People — the  Brown 
Man  of  Colorado,"  "Legends  of  a  Van- 
ishing People — the  Red  Man  of  Colo- 
rado" and  "Legends  of  a  Conquering 
People — the    White    Man   of   Colorado." 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


49 


How  to  Make  the  Roberts 
Receiver 

(Continued  from  page  20) 
variable  vernier  condensers,  one  audio 
frequency  transformer  having  a  ratio  of 
about  4  to  1,  one  standard  socket,  one 
UV-199  socket,  one  midget  variable  con- 
denser, two  .0025  M.F.  fixed  mica  con- 
densers, one  .00025  M.F.  lixed  mica  grid 
condenser,  one  2  megohm  grid  leak,  one 
bakelite  panel  7x14x3-16  inches,  one 
baseboard  6x13  1-2x1-2  inches,  one  25 
ohm  rheostat,  one  60  ohm  rheostat,  ten 
binding  posts,  one  UV-201-A  vacuum 
tube,  one  UV-199  vacuum  tube,  four 
dry  cells,  one  4  1-2  volt  "C"  battery, 
two  45  volt  plate  batteries,  about  20  feet 
of  No.  14  bus  bar  wire,  a  loud  speaker 
and  a  pair  of  good  phones. 

Wiring  the  Set 

THE  set  is  wired  as  follows:  from  the 
aerial  binding  post  to  the  outside 
terminal  of  coil  1  and  from  one  of  the  taps 
on  coil  1,  or  the  inside  end,  whichever 
gives  the  best  results,  to  the  ground  bind- 
ing post.  From  the  outside  terminal  of 
coil  2  to  the  stationary  plates  on  the  first 
variable  condenser  and  to  the  grid  post 
on  the  first  socket,  which  is  to  take  the 
UY-201-A  tube.  The  inside  terminal  of 
coil  2  is  connected  to  the  rotating  plates 
of  the  first  variable  condenser.  The  posi- 
tive of  the  "C"  battery  is  connected  to 
the  filament.  One  terminal  of  the  midget 
neutralizing  condenser  is  also  connected 
to  the  grid  of  the  first  tube  and  the  other 
terminal  of  this  condenser  is  connected 
to  the  inside  terminal  of  coil  3.  The  out- 
side terminal  of  this  coil  3  is  connected  to 
the  inside  terminal  of  coil  4,  to  the  remain- 
ing terminal  of  one  of  the  .0025  M.F. 
condensers,  and  to  one  of  the  output 
terminals,  which  may  be  the  top  spring 
of  a  single  circuit  jack  or  a  binding  post 
as  desired. 

The  outside  terminal  of  the  coil  5  is 
connected  to  the  plate  post  on  the  first 
tube.  The  outside  terminal  of  coil  5  is 
connected  to  the  stationary  plates  of  the 
second  variable  condenser  and  to  one 
terminal  of  the  grid  leak  and  condenser, 
the  other  terminal  of  the  grid  leak  and 
condenser  being  connected  to  the  grid 
post  on  the  second  socket,  which  is  the 
UV-199. 

The  inside  terminal  of  coil  6  is  con- 
nected to  the  plate  post  on  the  second 
socket  and  the  outside  terminal  is  con- 
nected to  the  remaining  terminal  of  the 
second  .0025  fixed  condenser  and  to  the 
post  "B"  on  the  audio  frequency  trans- 
former. The  other  post  on  the  trans- 
former marked  "P"  is  connected  to  the 
45  volt  tap  on  the  plate  battery.  (This 
is  at  the  junction  between  the  two  bat- 
teries.) The  negative  terminal  of  the 
plate  battery  is  connected  to  the  positive 
terminal  of  the  filament  batteries  (the 
dry  cells)  and  to  the  levers  of  both  of  the 
rheostats. 

The  other  rheostat  terminals  are  con- 
nected to  the  remaining  filament  posts  on 
their  respective  sockets,  as  shown.  The 
90  volt  positive  post  on  the  plate  battery 
is  connected  to  the  other  output  terminal, 
which  may  be  either  the  lower  spring  on 
a  single  circuit  jack,  or  a  binding  post  as 
desired. 


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The  above  headline  from  the  New  York 
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"This   veritable   wizard   of  the  ether  is  the 
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"The  Last  Word  in  Selectivity 
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50 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


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A  Five  Tube  Set  that  Reduces 
Wiring  Worries 


(Continued  from  page  IS) 


socket.  Replace  them  with  rwo  3-4-in. 
6-32  R.  H.  screws  in  the  opposite  direc- 
tion, with  the  round  heads  resting  directly 
on  top  of  the  contact  springs.  Put  the 
thumb  nuts  on  the  screws  under  the  base 
of  the  socket,  and  then  put  the  protruding 
ends  of  the  screws  light  through  the  tube 
panel  and  fasten  them  with  nuts  on  the 
underside.  Put  a  3-4-in.  6-32  R.  H.  screw 
through  the  mounting  hole  near  the  G 
terminal,  into  a  nut  between  the  socket 
base  and  the  tube  panel.  Fasten  with 
another  nut  under  the  tube  panel.  Slip 
the  eyelet  hole  of  the  0.00025  mfd.  grid 
condenser  through  the  G  terminal  screw, 
and  fasten  it  with  the  thumb  nut.  Snap 
the  gridleak  in  place  on   the  condenser. 

Remove  all  four  terminal  screws  of 
the  UV-199  socket,  replacing  them  with 
3-4-in.  6-32  R.  H.  screws,  and  fasten  the 
socket  to  the  tube  panel  in  the  same  way 
as  the  other,  remembering  to  put  the 
necessary  lugs  under  the  nuts  below  the 
panel,  and  being  careful  to  keep  the 
socket  turned  in  the  position  shown  in 
the  picture  wiring  diagram. 

Take  two  M-in-  6-32  R.  H.  screws  and 
put  a  lug  under  the  head  of  each.  Put 
these  through  the  two  holes  at  2  and  6 
in  the  tube  panel,  put  a  lug  on  each, 
under  the  panel,  and  fasten  with  nuts. 

3.  Now  proceed  with  the  wiring  of  the 
tube  panel.  While  doing  this  be  sure  to 
keep  the  panel  perfectly  flat  so  that  no 
wires  will  sag  when  it  is  finally  fastened 
to  the  front  panel. 

Connect  1,  the  right  hand  binding  post 
of  the  amplifier  unit,  looking  at  the  tube 
panel  from  the  rear,  to  2.  Connect  3, 
one  of  the  lugs  under  the  +  terminal  of  . 
the  standard  socket,  to  4,  the  F  terminal 
of  the  UV-199  socket.  Connect  5,  the 
P  terminal  of  this  socket,  to  6. 

4.  Mount  the  three  rheostats  on  the 
front  panel,  in  the  order  shown  in  the 
picture  wiring  diagram,  using  the  screws 
provided.  Put  lugs  on  the  terminal 
screws,  bent  as  shown.  Remove  the  two 
binding  posts  from  the  switch,  and  re- 
place them  with  6-32  nuts,  putting  a 
soldering  lug  under  each  nut.  Mount 
the  switch  on  the  panel,  being  sure  to 
place  the  Off-On  sign  against  the  panel 
and  behind  the  mounting  nut.  The  slot 
for  the  key  must  be  in  a  horizontal  posi- 
tion. Make  sure  that  the  soldering  lug 
which  rests  on  the  small  insulating  washer 
does  not  touch  the  metal  switch  case  for 
this  will  short  the  switch. 

Mount  the  two  jacks  w-ith  the  terminals 
arranged  in  the  order  shown  and  fasten 
the  lugs  under  the  terminal  nuts. 

Take  four  of  the  mounting  legs  and 
fasten  the  long  parts  to  the  four  screws 
which  hold  the  front  and  rear  end  plates 
of  condenser  C2  to  the  lower  spacing 
pillars.  Remove  these  screws  one  at  a 
time,  put  them  through  the  upper  holes 


to  the  left  hand  side  of  condenser  Ci, 
looking  at  the  set  from  the  rear,  in  the 
same  way.  Take  the  three  binding  posts 
and  slip  the  screws  into  the  Ai,  A2,  and 
GND  eyelet  terminals  of  the  antenna 
coil,  fastening  them  with  the  nuts  on 
the  inside.  Put  a  lug  on  the  inside  at 
the  Ai  post,  under  the  nut. 

To  remove  the  dial  from  the  variable 
condenser,  first  loosen  the  set  screw 
which  holds  the  knob  to  the  shaft  and 
remove  the  knob.  Take  out  the  three 
R.  H.  screws  wnich  fasten  the  large  dial 
to  the  friction  disc  box,  remove  the  four 
screws  holding  the  box  to  the  condenser 
mounting  posts,  and  loosen  the  set  screw 
on  the  collar  which  fits  over  the  con- 
denser shaft.  You  can  now  pull  the  box 
and  collar  off  the  shaft.  You  will  find 
three  washers  on  each  condenser  mount- 
ing post.  Take  off  all  but  one  from  each 
post. 

Remove  the  set  screw  from  the  collar, 
put  the  collar  through  the  large  hole  in 
the  front  panel,  and  screw  the  set  screw 
back  again.  Put  the  condenser  behind 
the  panel,  and  put  in  the  screws  which 
go  through  the  friction  disc  box  and 
thread  into  the  mounting  pillars,  put 
back  the  three  small  screws  holding  the 
dial  to  the  gear  box  and,  finally,  fasten 
the  knob  in  place  by  tightening  the  set 
screw  in  it.  Turn  the  condenser  plates 
so  that  they  are  totally  interleaved, 
loosen  the  set  screw  on  the  collar  over 
the  condenser  shaft,  set  the  dial  so  that 
the  100  division  line  coincides  with  the 
index  line  engraved  on  the  panel,  and 
tighten  the  set  screw  again.  Screw  the 
small  knob  on  to  the  threaded  end  of  the 
tickler  shaft.  Fasten  a  coil  mounting 
pillar  to  the  front  panel  at  the  right  hand 
end  with  a  1-2-in.  6-32  F.  H.  screw.  No 
put  the  three  knobs  on  the  rheostats, 
locking  them  to  the  contact  arms  by 
means  of  the  thumb  nuts  at  the  rear. 
The  index  line  on  each  knob  should  co- 
incide with  the  off  mark  on  the  dial  when 
the  contact  arm  is  all  the  way  around 
to   the   left. 

5.  Connect  the  three  terminals  7,  8, 
9  of  the  rheostats  together.  This  wire 
shoiild  run  close  to  the  front  panel. 
Connect  8  to  10.  Fasten  the  front  panel 
to  the  tube  panel  by  means  of  1-2-in. 
6-32  R.  H.  screws  and  nuts  through  the 
short  ends  of  the  mounting  legs  on  the 
variable  condensers.  Put  a  lug  under 
the  front  mounting  screw  nut  on  con- 
denser Ci  and  a  lug  under  each  nut  of 
the  rear  mounting  screws  on  C2.  Fasten 
the  angle  bracket  at  the  amplifier  end 
of  the  tube  panel  to  the  coil  mounting 
pillar  on  the  front  panel  with  a  J^-in. 
6-32  R.  H.  screw.  About  M"in-  of  tl»s 
screw  will  have  to  be  clipped  off  before 
inserting  it. 

Testing  and  Installation 


of  the  mounting  leg,  and  turn  them  back 

into  the  pillars  again.      Keep  the   short  T^HIS  completes  the  wiring  of  the  set. 

ends  of  the  legs  pointing  toward  the  rear  -*-  The  antenna  and  ground  connections 

of  the   set.      Fasten   two   mounting  legs  are  made  directly  to  binding  posts  on  the 

Tested  and  Approved  by  RADIO  AGE     ¥ 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


51 


antenna  coil.  The  battery  connections 
are  made  to  the  binding  posts  on  the 
A.  F.  amplifier  unit.  The  two  binding 
posts  marked  Input  P  and  B  should  have 
these  markings  removed.  The  post  for- 
merly marked  P  now  becomes  the  +  90V 
terminal,  and  the  one  formerly  marked 
B  is  now  the  DET+  terminal.  These 
markings  are  shown  correctly  in  the  pic- 
ture wiring  diagram.  The  markings  for 
the  rest  of  the  binding  posts  remain  as 
they  are. 

Connect  a  6-volt  storage  A  battery  to 
the  A+  and  A—  binding  posts.  In- 
sert the  tubes  and  turn  the  key  in  the 
lock  switch  to  the  right.  When  the  rheo- 
stats are  turned  up,  the  tubes  should  light. 
If  everything  seems  all  right,  connect  90 
volts  of  B  battery  across  the  B  —  and 
90V+  binding  post,  and  bring  off  a  45- 
volt  tap  to  the  DET+  binding  post. 
Connect  either  the  135  or  150-volt  tap 
to  the  +150V.  binding  post.  Light  the 
filaments  and  plug  the  phones  or  loud 
speaker  first  into  the  detector  jack  and 
then  into  the  last  stage  jack.  A  strong 
click  should  be  heard  in  both  cases. 

Connect  the  antenna  and  ground  and 
set  the  tickler  coil  at  right  angles  to  the 
main  winding.  Revolve  the  left  hand 
condenser  slowly  wnile  the  other  is 
turned  back  and  forth. 


Co-op  Radio  Station  Being 
Planned 

A  cooperative  broadcasting  station  to 
be  owned  and  operated  in  or  near  Chicago 
by  local  radio  fans  themselves  may  be  on 
the  air  some  time  next  Winter  if  plans 
proposed  by  Gustave  Frankel,  president 
of  th^  Mohawk  Electric  Corporation, 
materialize.  The  idea  has  received  the 
endorsement  of  scores  of  leading  citizens, 
besides  winning  instant  approval  from 
many  other  quarters. 

Such  a  station,  it  is  believed,  would  be 
a  forward  step  in  the  history  of  broad- 
casting. While  there  is  at  this  time  no 
imminent  danger  of  anything  like  a  de- 
cline in  broadcasting  the  establishing  of 
this  station  would  aid  immensely  in 
solving  any  impending  problem  of  that 
nature. 

"We  have  been  altogether  too  depend- 
ent upon  others  for  our  daily  radio 
programs,"  said  Mr.  Frankel  in  dis- 
cussing the  project  recently.  "The  air 
has  been  filled  with  so  much  entertain- 
ment that  we  have  come  to  take  it  for 
granted,  as  if  it  had  always  been  there. 
There  is  no  gainsaying  that  while  listen- 
ing over  the  radio  is  no  longer  a  fad, 
broadcasting  still  is.  The  people  who  are 
providing  us  with  entertainment  today 
are  doing  it  at  their  own  expense,  some 
of  them  for  the  sake  of  the  advertising 
derived,  but  most  of  them  for  more  or 
less  philanthropical  reasons.  In  time 
some  of  these  stations  will  go  out  of 
commission. 

"Then,  again,  there  are  well-founded 
rumors  that  a  certain  powerful  trust  is 
seeking  a  monopoly  of  broadcasting  with 
a  view  toward  ultimately  making  listen- 
ers pay  for  their  service.  Cooperative 
stations,  supported  by  the  people  by 
popular  subscription,  would  guard  against 
any  such  monopoly.  Other  advantages 
would  be  the  privilege  of  arranging  their 
own  programs  and  selecting  their  own 
talent." 

The  expense  of  building  and  main- 
taining such  a  station,  Mr.  Frankel 
pointed  out,  could  be  easily  "defrayed  if 
25,000  persons  contributed. 


RADIO 

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Designer  of  the  4-Tube 

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developments  of  McMurdo  Silver,  Assoc,  I.  R.  E.,  and  designer 
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1    On-off  Switch 60 

1   .00025   Mica  Condenser  with   Leak  Clips 45 

1    .002  Mica  Condenser 40 

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52 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Sales  Distributor  Wanted 

Reliable  Man  Who  Is  Mechanically- 
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information  address  your  letter  to: 

Mr.  Higgins,  Sales  Manager 

1207  North  Shore  Ave.,  Chicago 


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Reducing  STATIC  Disturbances 
This  Summer 


(Continued  from  page  10) 


Tuned  circuits,  tuned  to  a  given  wave- 
length, are  not  set  to  oscillating  by  other 
wavelengths  unless  these  waves  are  un- 
sually  strong.  We  all  know  that  most 
receivers  will  oscillate  at  their  tuned 
frequency  when  in  the  vicinity  of  a 
powerful  broadcasting  station,  even  when 
the  station  is  operating  on  a  widely 
different  wavelength.  The  shock  must 
be  many  times  the  ordinary  signal 
strength  to  set  up  such  conditions,  and 
the  atmospheric  contact  charges  are 
heavy  enough  to  do  this  very  thing. 
In  other  words,  we  now  have  no  means  of 
separating  the  desired  signal  from  the 
undesired  static,  since  both  disturbances 
oscillate  the  set  at  the  same  frequency. 
The  tuning  unit  is  ineffective  in  such  a 
case  and  must  be  given  outside  aid.  This 
may  be  compared  to  the  case  of  a  tuning 
fork  which  is  free  to  vibrate  at  a  fixed 
frequency,  but  which  will  also  vibrate 
at  this  frequency  when  struck  by  a  force 
of  any  other  frequency. 

Simple  Static  Reducers 

It  is  an  old  saying  that  the  elimination 
|  of  static  means  a  reduction  of  signal 
strength,  and  this  is  true  of  most  static 
eliminators  so  far  devised.  However,  the 
weakening  of  the  signal  is  not  of  so  much 
importance  as  the  relative  weakening 
of  the  static  and  the  signal,  or  the 
"Signal  Static  ratio"  as  it  is  called. 
If  a  certain  system  weakens  the  static 
at  a  more  rapid  rate  than  it  weakens  the 
signal,  then  we  will  eventually  reach  a 
point  where  the  static  will  disappear 
entirely  with  some  of  the  signal  still  in 
evidence.  It  is  only  when  the  strength 
of  the  static  greatly  exceeds  the  signal 
that  it  becomes  highly  objectionable,  and 
even  when  they  are  equal  the  practical 
effect  is  not  bad. 

One  of  the  simplest  eliminators  of  the 
"high  loss"  type  is  the  crystal  eliminator 
of  Fig.  4.  A  crystal  detector  (CD)  is 
connected  across  the  aerial  and  ground 
posts  (ANT)  and  (GND)  of  the  receiver 
(R)  and  through  the  choke  coil  (S).  The 
choke  coil  can  be  adjusted  so  that  the 
high  frequency  radio  waves  are  retarded, 
while  the  low  frequency  static  goes  to 
ground.  It  makes  no  difference  how 
carefully  this  device  may  be  adjusted 
for  there  will  always  be  some  loss  of  radio 
waves  to  ground  and  half  the  static 
waves  or  charges  will  always  be  thrown 
over  into  the  set  for  half  the  static  waves 
cannot  pass  through  the  detector  (CD). 
However,  this  is  frequently  of  service  and 
is  at  least  a  partial  solution  of  the  prob- 
lem. A  low  capacity  condenser  (CI) 
placed  in  the  cross-aerial-line  to  the 
receiver,  is  adjusted  so  that  the  high  fre- 
quency radio  waves  will  pass  into  the 
set,  but  so  that  the  capacity  will  not  be 
great  enough  to  pass  the  low  frequency 
static  waves.  This  may  or  may  not  be 
of  assistance  with  lightning  discharges, 
but  is  usually  effective  with  local  "con- 
tact static"  met  with  in  clear  weather. 
As  the  crystal  detector  passes  half  the 
waves,  it  tends  to  give  a  signal  static 
ratio  of  one  to  one. 

Tested  and  Approved  by  RADIO  AGE     * 


Another  stunt,  but  not  so  good  as  the 
first,  is  to  place  a  high  resistance  (GL)  or 
grid  leak  across  the  posts  of  the  receiver 
(R)  as  shown  in  Fig.  5.  This  should  be  a 
variable  resistance  or  leak  which  may 
vary  from  50,000  ohms  to  one  megohm 
according  to  conditions.  It  is  strictly  an 
emergency  aid,  for  it  allows  a  greater  per- 
centage of  the  signal  to  escape  to  ground 
than  the  crystal  detector  type. 

Ground    Chokes    (Static    Drains) 

A  simple  and  often  very  effective 
method  is  the  "ground  choke  coil" 
method  shown  by  Figs.  6-7.  These  are 
suitable  only  with  inductively  coupled 
receivers  having  a  primary  aerial  circuit 
electrically  separated  from  the  secondary 
circuit.  This  includes  sets  equipped 
with  loose-couplers,  vario-couplers,  or 
other  two  and  three  circuit  tuning  units. 

In  Fig.  6,  a  choke  coil  (I)  is  connected 
directly  from  the  aerial  to  ground.  This 
choke  must  have  a  sufficiently  high  in- 
ductive value  to  hold  back  the  longest 
radio  waves  that  we  expect  to  receive. 
The  long  wave  static  will  pass  freely 
through  the  choke  without  the  high  fre- 
quency radio  waves  following.  I  have 
seen  all  sorts  of  values  used,  for  (I), 
ranging  from  a  400  turn  honeycomb  coil 
to  the  secondary  winding  of  an  audio 
transformer.  I  have  had  the  best  results 
by  connecting  the  primary  coil  of  an 
audio  transformer  at  (I),  leaving  the 
secondary  coil  open,  but  this  may  not 
suit  every  case  as  well  as  it  does  mine. 
In  any  event,  the  inductance  must  be 
very  much  higher  than  that  employed  for 
tuning  in  broadcasting  wavelengths. 

Fig.  7  is  an  alternative  arrangement 
of  the  same  choke  coil  (I)  in  which  the 
choke  is  placed  in  series  with  the  ground 
wire  of  the  receiver.  In  some  cases,  and 
with  certain  types  of  receivers,  this  may 
work  better  than  the  arrangement  in 
Fig.  6.  It  is  easy  to  try,  and  there- 
fore I  will  put  the  selection  up  to  you. 

Tuned  Traps   (Selectors) 
"^/■ERY  often  the  wave  trap  idea  works 
out  successfully,  and  has  the  further 


V 


advantage  that  it  can  also  be  used  to  in- 
crease the  selectivity  of  the  receiver. 
In  Fig.  8  we  have  a  combination  of  a 
variable  condenser  (CI)  and  a  honey- 
comb coil  (L)  connected  across  the  aerial 
and  ground  posts  of  the  receiver  (R). 
This  arrangement  is  adapted  only  to 
two  or  three  circuit  tuners  with  induc- 
tively coupled  aerial  circuits.  It  will 
short-circuit  a  single  circuit  receiver 
of  the  ultra-audion  type. 

By  tuning  the  variable  condenser  (CI), 
the  wavelength  of  the  trap  will  be  varied 
so  that  all  the  radio  frequency  signals  are 
shunted  into  the  receiver  while  the  un- 
desired waves  of  different  wavelengths 
pass  through  to  ground  without  enter- 
ing the  receiver.  Under  some  conditions 
this  is  highly  effective.  It  is  difficult  to 
prescribe  any  definite  sizes  for  the  con- 
denser and  coil  owing  to  the  great  varia- 
tion in  conditions,  but  as  a  starter  I 
would  say  that  a  23  plate  (0.0005  mf) 
variable   condenser   with   a   50  turn   coil 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


53 


(L)  would  be  about  right.  A  vernier 
must  be  used,  as  the  trap  tunes  very 
sharply  and  there  is  a  certain  hot  spot 
on  the  dial  which  covers  only  one  or  two 
divisions. 

Fig.  9  shows  the  same  scheme  adapted 
to  single  circuit  tuners  with  the  trap 
placed  in  series  with  the  set.  This  also 
works  well  with  certain  two  circuit 
tuners,  and  both  methods  should  be 
tried  out  with  two  circuit  tuners  until 
the  best  results  are  obtained.  The  con- 
denser and  coil  can  be  mounted  in  a 
separate  cabinet,  making  a  convenient 
•  unit  for  tuning  your  set. 

Aerial  Specifications 

For  the  minimum  reception  of  static, 
the  aerial  conditions  must  be  carefully 
controlled,  even  when  static  drains  are 
employed.  For  Summer  reception  a  low 
aerial  is  the  best,  an  aerial  that  is  not 
more  than  25  or  30  feet  above  the 
ground.  This  follows  from  the  data  in 
Fig.  1,  which  shows  that  atmospheric 
potentials  increase  rapidly  for  every  in- 
crease in  altitude.  A  single  wire  not 
more  than  60  feet  long  is  the  best,  and 
while  this  may  reduce  the  signal  strength 
slightly,  it  also  decreases  the  static  more 
rapidly,  thus  giving  a  better  signal  static 
ratio  than  a  longer  wire.  The  lower  the 
natural  period  of  the  aerial  system,  the 
less  likely  it  is  to  respond  to  low  fre- 
quency static  impulses. 

Where  possible,  the  aerial  should  have 
strong  directional  qualities  so  that  it  will 
embrace  as  small  an  area  of  static  dis- 
turbance as  possible.  The  fact  that  a 
loop  aerial  is  very  directional,  picking  up 
only  the  signals  that  lie  in  the  plane  of 
the  loop,  makes  this  type  almost  ideal 
for  Summer  use.  Umbrella  or  "V"  type 
aerials  are  to  be  avoided. 

Inductive  Type  Reducers 

A  type  of  tuned  absorption  reducer  is 
frequently  very  successful  and  is  easily 
adjusted  to  local  conditions.  This  is  a 
modified  form  of  the  traps  already  de- 
scribed. In  addition  to  reducing  static,  it 
also  makes  the  circuit  more  selective.  In 
Fig.  10  we  have  the  common  form  of 
coupler  having  the  aperiodic  primary 
(P)  and  the  secondary  (S),  the  latter 
being  tuned  as  usual  by  the  variable  con- 
condenser  (CI).  This  is  the  common 
tuning  unit  employed  on  the  majority 
of  present  day  sets.  An  addition  is  made 
by  winding  the  coil  (T)  on  the  end  of  the 
secondary  in  inductive  relation  to  (S).  A 
variable  condenser  (C2)  across  coil  (T) 
makes  very  close  tuning  possible,  and  a 
very  marked  reduction  in  static  generally 
follows.  The  coil  (T)  may  contain  from 
40  to  60  turns  of  small  wire,  say  No  30 
or  No.  32.  This  will  save  space  and  will 
make  the  unit  more  compact.  The  coil 
(T)  is  located  about  1-2  inch  from  the 
end  of  (S).  Condenser  (C2)  is  usually 
about  0.0005  mf  capacity.  Still  sharper 
tuning  is  possible  by  placing  the  coil 
near  the  primary  instead  of  near  the 
secondary.  This  is  shown  in  Fig.  11, 
where  the  same  size  units  are  used. 
In  fact,  the  sharper  the  tuning  and  the 
looser  the  coupling,  the  less  satitc  we  will 
receive. 

Resonance  Coils 

Probably  the  most  effective  static  re- 
ducer yet  devised  is  the  "resonance"  type 


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RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


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developed  by  the  Signal  Corps  of  the 
United  States  Army.  This  is  an  artificial 
antenna  in  very  compact  form  made  by 
wrapping  about  400  turns  of  wire  around 
a  long  cylinder,  and  then  capacitatively 
connecting  the  receiving  circuit  at  critical 
points  on  the  coil.  Remarkable  results 
are  said  to  have  been  obtained  with  this 
arrangement  without  materially  reducing 
the  strength  of  the  signals. 

Fig.  12  shows  the  circuit  where  (L) 
is  the  coil  and  (P)  is  a  sliding  split  ring, 
which  closely  embraces  the  coil  but  does 
not  make  actual  electrical  contact  with 
the  wire.  In  effect,  (P)  is  the  plate  of  a 
condenser  connected  to  the  antenna  post 
(ANT)  of  the  set  (R)  which  picks  up 
certain  desired  impulses  in  the  coil 
and  transmits  them  to  the  receiver. 
The  ring  (P)  is  split  or  made  discontinu- 
ous so  that  eddy  currents  will  not  be 
formed  in  the  metal.  When  working  on 
long  wavelengths,  the  coil  (L)  is  about 
38  inches  long  and  is  wound  on  a  2  3-4 
inch  diameter  tube.  This  is  a  single 
layer  winding  and  is  therefore  objection- 
ably long. 

For  work  on  broadcasting  wavelengths, 
the  coil  can  be  much  condensed  by  using 
a  single  layer  winding  of  No.  30  gauge 
wire  on  a  tube  18  inches  long  and  with  a 
diameter  of  from  three  to  four  inches. 
A  further  reduction  in  size  may  be  had 
by  employing  a  double  banked  winding, 
the  winding  being  divided  up  into  sec- 
tions one  inch  long.  With  a  banked 
winding,  the  length  is  shortened  to  about 
12  inches  with  the  diameter  remaining 
as  before.  The  size  of  the  wire  is  not  of 
importance  and  it  may  be  that  even 
finer  wire  than  No.  30  could  be  used 
with  good  results. 

The  sliding  ring  (P)  by  capacity  col- 
lection picks  up  radio  waves  that  cor- 
respond in  wavelength  to  the  inductive 
portion  of  the  coil  (D)  included  between 
the  ring  and  the  aerial  connection; 
hence  any  desired  wavelength  can  be 
picked  up  in  this  manner  and  transferred 
to  the  grid  of  the  tube.  By  using  two 
collector  rings  on  a  single  coil,  and  located 
in  different  positions  along  the  length, 
two  different  wavelengths  or  frequencies 
can  be  picked  up,  which  immediately 
suggest  that  one  ring  can  be  used  for 
grounding  static  discharges  while  the 
second  ring  can  be  used  to  transmit  the 
desired  radio  signal  to  the  receiving  set. 

Fig.  13  shows  how  two  collector  rings, 
(P)  and  (V)  can  be  employed  for  the 
elimination  of  static.  In  this  figure,  the 
guard  ring  (V)  is  connected  to  earth 
through  the  trap  (C2-L2)  while  the  col- 
lector ring  (P)  carries  the  radio  signal  to 
the  antenna  post  of  the  receiver  (R). 
The  ground  from  (V)  can  be  a  direct 
ground,  or  it  can  be  arranged  with  the 
trap  (C2-L2)  as  shown,  for  better  control. 
Once  adjusted,  (V)  remains  constantly 
in  one  position  on  the  coil,  for  the  length 
is  so  chosen  that  it  includes  the  band  of 
static  waves  having  a  frequencj-  of 
between  200  and  300  cycles  per  second. 
The  length  of  (V)  is  from  one-third  to 
one-half  the  total  length  of  the  coil 
(LI).     . 

Fig.   14  is  a  simplified  version  of  the 

resonance  coil  that  can  be  built  by  the 

home     experimenter,     the     construction 

recalling  the  old  time  single-slide  tuner 

*     Tested  and  Approved  by  RADIO  AGE     * 


except  that  the  slider  does  not  make 
actual  metal-to-metal  contact  with  the 
wire  coil.  This  is  by  far  the  best  arrange- 
ment that  can  be  used  by  the  amateur, 
but  it  is  somewhat  cumbersome.  The 
coil  (L)  consists  of  about  400  turns  of 
No.  18  D.  C.  C.  wire  wound  on  a  four- 
inch  diameter  tube.  The  square  brass 
rod  slider  guide  (S)  is  fastened  to  the 
tube  so  that  free  movement  of  (P)  can 
be  had  from  end  to  end  of  the  coil. 

It  is  essential  that  (P)  be  split  to  pre- 
vent the  circulation  of  eddy  currents,  and 
this  is  effectively  attained  by  making  (P) 
in  two  pieces  with  a  strip  of  insulation  be- 
tween them.  In  Fig.  IS  is  a  cross-section 
through  the  assembly  showing  the  two 
halves  (P)  attached  to  and  separated 
by  the  hard  insulation  (I),  the  insulation 
(I)  also  acting  with  a  sliding  fit  on  the 
slider  guide  (S).  The  parts  (P)  can  be 
made  of  sheet  copper  bent  to  an  arc  which 
closely  fits  over  the  wire.  The  arc  of 
embrace  is  about  one-third  the  total 
circumference  or  120  degrees,  although 
this  is  not  an  exact  or  critical  dimension. 
Returning  to  Fig.  14,  the  width  of  the 
slider  may  be  equal  to  from  eight  to  ten 
turns  of  the  coil. 

Loose  Coupling  Methods 

There  is  a  distinct  relation  between 
loose  coupling  and  static,  or  between  se- 
lectivity and  static.  A  very  loose  coup- 
ling between  the  primary  and  secondary 
coils  of  your  tuning  unit  will  be  of  great 
assistance  in  getting  rid  of  the  noises. 
If  you  have  a  single  circuit  tuner  or  a 
very  closely  coupled  two  circuit  tuner, 
then  it  will  be  difficult  to  get  rid  of  the 
trouble  without  outside  assistance.  Uni- 
polar tuners  or  Marconi  "link"  couplers 
are  of  great  assistance  in  ridding  your 
circuit  of  static  and  at  the  same  time 
increasing  their  selectivity.  Selectivity 
of  this  sort  reduces  the  signal  strength 
somewhat,  but  as  it  can  reduce  the  static 
at  a  still  greater  rate,  the  ratio  of  signal 
strength  to  static  is  greatly  improved. 

A  "unipolar  tuner"  is  one  in  which 
there  is  only  a  single  connection  (g) 
running  from  the  tuning  inductance  to 
the  grid  of  the  tube,  as  in  Fig.  16.  There 
is  no  grid  return  wire.  The  coil  (L)  is 
tuned  by  the  variable  condenser  (CI)  as 
usual.  This  is  an  exceedingly  sharp 
tuner,  and  one  in  which  static  capacity 
effects  can  be  reduced  to  minimum.  The 
values  of  (CI)  and  (L)  are  as  usual  with 
this  tuner. 

A  type  of  tuner  once  used  by  the 
Marconi  Company  is  shown  in  Fig.  17, 
which  also  provides  for  extreme  selec- 
tivity. The  primary  inductance  (LI) 
is  tuned  by  the  variable  condenser  (CI), 
and  instead  of  being  directly  coupled  by 
induction  to  the  secondary  coil  (L2),  the 
connection  is  made  bj'  the  "link"  of  wire 
(M).  The  connection  (M)  consists  of 
two  or  three  turns  of  lamp  cord  about 
each  of  the  coils  (LI)  and  (L2),  and  then 
the  two  coils  (L1-L2)  are  placed  about 
one  foot  apart  or  at  right  angles  to  one 
another  so  that  there  can  be  no  direct 
inductive  coupling  between  the  primary 
and  secondary  circuits.  As  a  heavy 
current  flows  in  (M),  it  must  be  of  very 
heavy  low-resistance  wire  or  preferably 
of  heavy  lamp  cord.  The  secondary  (L2) 
is  tuned  by  the  second  variable  condenser 
in  the  usual  manner.       (To  page  55) 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


55 


Figs.  16-17  show  only  the  "front  ends" 
of  the  receiving  circuits  for  simplicity 
in  describing  the  methods.  The  rest  of 
the  circuit  can  be  of  any  imaginable 
type;  regenerative,  radio  frequency  or 
reflex.  In  the  unipolar  type,  you  should 
note  that  the  grid  leak  (GL)  runs  from 
the  grid  directly  to  the  (-A)  of  the 
battery  and  is  not  in  parallel  with  the 
grid  condenser.  This  is  made  necessary 
for  the  reason  that  there  is  no  grid  return 
line  in  this  circuit,  and  if  the  parallel 
connection  were  used,  the  circuit  through 
the  grid  leak  would  not  be  completed. 

Modulated  Primary  Type 

TD  ASED  on  the  theory  that  any  tuned 
-*-*  circuit  will  oscillate  at  a  given  fre- 
quency determined  by  the  tuning  when  ex- 
cited by  the  impact  of  any  strong  wave  of 
any  frequency,  a  very  original  eliminator 
has  been  devised  by  Dr.  McCaa.  This  is 
a  rather  complicated  circuit,  both  in 
construction  and  theory,  and  rather 
suggests  a  combination  of  the  super- 
heterodyne and  the  super-regenerative 
principles  in  oscillating  the  circuit  and  in 
opening  and  -  electrically  closing  the 
circuit  for  the  admission  of  signals  only. 
An  external  oscillator  circuit  and  tube 
is  supplied  for  the  excitation  of  the  re- 
ceiving circuit,  which  is  tuned  to  the 
wavelength  of  the  incoming  signal  or  to 
a  harmonic  of  the  signal.  Static  is  not 
entirely  eliminated  but  it  is  reduced  in 
strength  until  it  is  equal  to  the  signal 
strength.  This  is  a  greater  advance 
than  would  be  considered  at  first  glance. 
A  schematic  diagram  is  shown  in  Fig. 
18  where  (P)  and  (S)  are  the  primary 
and  secondary  coils  respectively  of  the 
usual  tuning  unit.  The  secondary  (S)  of 
the  receiver  is  tuned  to  wavelength  by  the 
variable  condenser  (C2)  as  in  the  majority 
of  receiving  circuits.  An  oscillator 
circuit  of  the  super-heterodyne  type  is 
inductively  coupled  to  the  secondary  coil 
(S)  of  the  receiving  circuit  by  the  coup- 
ling coil  (L2)  of  the  intermediate  circuit 
(L1-L2).  By  varying  the  condenser  dial 
(CI)  of  the  oscillator,  the  impressed  oscil- 
lations on  (S)  can  be  controlled  to  meet 
the  requirements  of  the  incoming  signal 
just  as  with  the  oscillator  circuit  of  a 
super-heterodyne.  When  the  oscillator 
creates  a  wave  that  exactly  opposes  the 
signal  wave  entering  the  aerial,  the  inter- 
mediate circuit  (L1-L2)  is  neutralized, 
and  (S)  is  excited  by  the  signal  together 
with  a  little  of  the  static.  The  signal  is 
received,  and  all  of  the  static  whose 
voltage  does  not  exceed  the  voltage  of 
the  signal.  In  other  words,  the  worst 
that  can  happen  is  to  have  a  static 
"bump"  that  is  equal  to  the  signal 
strength.  The  static  can  never  exceed 
the  signal,  and  generally  is  somewhat 
less. 

Cascade  Balanced  System 
Getting  rid  of  the  static  by  means  of 
successive  elimination  has  been  proposed 
many  times  with  varying  results.  In 
other  words,  the  output  of  the  aerial  is 
led  through  a  succession  of  inductances 
until  all  of  the  undesired  waves  are 
grounded  and  only  the  desired  signals 
reach  the  tube.  In  general,  this  is  ex- 
actly the  reason  for  the  selectivity  of 
the  common  five  tube  tuned  radio  fre- 
quency receiver,  for  three  stages  of  tuning 


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HOW  MUCH  COUPLING? 

Coupling  is  a  subject  that  interests  every  experimenter  desiring  to  im- 
prove the  operation  of  his  set.  How  about  your  coupling  troubles7 
Brainard  Foote  takes  them  up  one  by  one  and  solves  them  in  an  en- 
lightening article  he  has  written  for  the  July  RADIO  AGE,  on  the  stands 
June  15. 

Tested  and  Approved  by  RADIO  AGE     * 


56 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


eliminate  what  can  not  be  accomplished 
by  one  stage  alone. 

Fig.  19  shows  a  typical  example  of  this 
sort  of  arrangement  employing  three 
inductance  coils  (LI),  (L2)  and  (L3)  con- 
nected in  cascade  with  the  receiver  tube 
(T).  The  lower  ends  of  the  coils  are  all 
grounded  at  {bl-b2-b3)  for  the  elimina- 
tion of  the  static.  The  other  ends  of 
the  coils  {al-a2-a3)  lead  indirectly  to 
the  grid  of  the  tube  through  a  series  of 
intermediate  taps  {ml-mZ-m3).  By 
varying  the  position  of  the  taps  (ml- 
m2-m3)  we  have  a  means  of  separating 
low  frequencies  from  high  frequencies  or  a 
total  of  three  different  wavelengths. 

For  example,  if  (ml)  is  nearer  to  (al) 
than  to  (bl),  then  the  inductance  of  the 
upper  end  of  the  coil  will  be  less  than  the 
lower,  and  the  high  frequency  current 
will  pass  out  through  (al)  to  (m2)  of  the 
succeeding  coil,  while  the  low  wave- 
lengths will  be  grounded  'at  (bl-b2),  and 
so  on  through  the  series. 

(Copyright,  1925.  By  Radio  Age,  Ino. 


The  Joys  of  Outdoor 
Radio 

(Continued  from  page  12) 

it  if  I  came  back  that  way;  otherwise 
they  could  keep  it  until  my  next  trip, 
which   might  be  a  year  or  more  later. 

But  I  did  not  charge  it  to  profit  and 
loss.  In  the  car  they  placed  a  "snack" 
before  I  started  on.  There  was  a  leg  of 
'possum,  a  wild  strawberry  shortcake, 
and  enough  wild  honey  to  sweeten  life 
for  weeks.  Also  a  quart  of  a  liquid, 
colorless  product  of  the  corn  fields  which 
was  of  no  use  to  me  but  which  would 
have  brought  a  good  price  on  the  New 
York  stock  exchange.  Beside  me  for 
a  distance  rode  a  pale-eyed,  long-whis- 
kered guide  who  showed  me  where  well- 
stocked  trout  pools  lay,  where  deer  and 
b'ar  abounded,  where  roads  were  only 
bad  and  where  they  were  worse. 

By  some  underground  system  my 
identity  was  so  quickly  and  so  thoroughly 
established  that  wherever  I  went  in 
those  mountains  in  the  days  that  fol- 
lowed I  was  received  with  friendly  nods 
and  abundant  hospitality  instead  of 
with  the  suspicion  with  which  city 
fellers  are  likely  to  be  watched. 


IF  YOU  DON'T  See  what 
you  need  in  RADIO  AGE'S 
Advertising  Columns,  write  to 
the  Radio  Age  Buyers'  Ser- 
vice, 500  N.  Dearborn  St., 
Chicago,  and  all  buying  speci- 
fications will  be  furnished  you 
free  of  charge. 


Maybe  an 

Opportunity 

awaits  You  in  the 

Radio  Age  Classified 

Section 

See  page  70 


An  Ideal  Four-Tube  Set  in 
Practical  Form 


(Continued  from  page  22) 


section  of  the  condenser  turned  down, 
as  in  Figure  2.  This  will  provide  a  firm 
mounting  for  the  antenna  coil  on  the  back 
of  the  condenser. 

All  screws  and  nuts  on  condensers, 
transformers,  sockets,  etc.  should  be 
tightened  up,  and  jacks  and  sockets  care- 
fully checked  for  proper  contact  and 
spring  tension.  Jack  springs  should 
make  good  contact  with  the  phone  plug, 
and  socket  springs  should  be  bent  up  to 
make  good  contact  with  the  tube-base 
pins.  Soldering  lugs  should  be  put  on 
the  tube  sockets,  the  filament  lugs  point- 
ing toward  the  panel  except  in  the  case  of 
audio  frequency  sockets.  The  two  lugs, 
one  on  either  of  these  sockets  that 
will  be  adjacent  when  the  sockets  are  on 
the  panel,  should  be  turned  toward  each 
other  so  that  the  wires  to  them  can  be 
put  in  without  touching  the  rheostat. 

Binding  posts  should  be  put  on  the 
panel,  with  lugs  pointing  straight  in 
under  the  screw  heads  of  each  post.  The 
binding  posts  now  being  on  the  panel,  the 
four  sockets,  rheostats,  jacks,  on-off 
switch  and  audio  transformers  should  be 
fastened  on  with  screws  and  nuts. 

Precautions  Before  Wiring 

T3EF0RE  starting  the  wiring,  a  well- 
*-*  tinned  soldering  iron  should  be 
heated,  or  an  electric  one  used,  and  a 
quantity  of  rosin-core  solder  and  a  can  of 
non-corrosive  soldering  paste  procured. 

The  wiring  should  be  done  according 
to  the  pictorial  diagram,  placing  the 
additional  parts  in  position  on  the  panel 
as  it  progresses  to  facilitate  easy  placing 
of  the  various  wires.  If  the  diagram  and 
Figure  2  are  studied,  no  difficulty  should 
be  encountered.  Upon  completion  the 
set  is  ready  for  test,  and  the  following 
accessories  will  be  needed: 

1  90  Volt  B-battery  (4  22J4  volt  or  2-45  volt  batteries). 

1  6  Volt  storage  battery,  if  storage  battery  tubes  are  used, 
or  three  dry  cells  if  UV  199  tubes  are  used. 

1  iyi  volt  C-battery. 

4  tubes  (UV  201-A  for  storage  battery  recommended)  or 
UV  199  with  adapters  if  dry  cell.  (The  use  of  199  sockets 
was  not  considered  as  there  are  no  satisfactory  panel- 
mounting  199  sockets,  and  adapters  with  standard 
sockets  make  a  satisfactory  electrical  arrangement,  and 
an  excellent  mechanical  one). 

1  Pair  of  phones  with  phone  plug,  or  loud  speaker  with 
plug,  or  preferably  both   (any  standard  make). 

A  suitable  antenna  would  consist  of  a 
70  to  100  foot  single  wire  run  beteeen  two 
trees  or  two  buildings.  The  lead-in  wire 
should  not  be  over  fifty  feet  long. 

The  set  should  now  be  connected  to  the 
antenna  and  ground  and  to  the  A-bat- 
tery,  but  not  the  B  or  C  batteries.  The 
tubes,  upon  insertion  in  their  sockets, 
should  light  up  if  the  on-off  switch  is 
pulled  out  and  the  rheostat  turned  on. 
If  they  do,  disconnect  the  A -(-battery  lead 
and  connect  it  first  to  the  B22  and  then 
to  the  B  90  binding  post.  If  the  tubes 
then  light,  the  wiring  is  incorrect  and 
should  be  checked.  Assuming  they  do 
not,  the  A  battery  should  be  reconnected 
properly,  and  the  B  and  C  batteries 
connected.  The  C+post  connects  to 
the  flexible  lead  soldered  to  the  on-off 
switch,  and  the  C—  post  connects  to  the 


flexible  lead  attached  to  the  F  terminals 
of  the  audio  transformers.  The  B  bat- 
teries should  be  connected  in  series  so 
that  22  volts  will  come  between  the  AB  — 
and  the  22  +  posts,  and  67  volts  between 
the  22+  and  90+  posts,  or  90  volts 
between  the  AB  —  and  the  90+  posts. 

Operation 

The  tickler  dial  should  be  turned  to 
zero  and  the  tubes  lighted  up  by  turning 
the  rheotast  about  three-quarters  on  for 
UV  201-A  tubes  or  one-quarter  on  for  UV 
199  tubes,  and  once  set  it  need  not  be 
varied,  but  should  always  be  operated  as 
low  as  is  consistent  with  good  signal 
strength.  The  first  two  condenser  dials 
should  be  rotated,  holding  about  the 
same  settings  over  their  entire  scales,  with 
the  phones  in  the  three-contact,  or  first 
stage  jack.  These  two  condenser  dials 
will  operate  as  the  first  two  dials  on  a 
neutrodyne,  keeping  about  the  same 
relative  separation  in  degrees  over  the 
entire  wavelength  range  of  the  receiver. 
If  there  is  any  tendency  for  the  RF 
amplifier  to  oscillate,  it  will  be  evidenced 
by  clicking  in  the  phones  at  certain  dial 
settings  on  the  lower,  and  possibly  on  the 
higher  waves.  If  stations  are  heard  as  a 
whistle,  it  means  the  amplifier  is  oscillating 
and  must  be  neutralized.  The  tickler 
has  been  left  set  at  zero. 

A  station  should  now  be  tuned  in  on  the 
lower  waves,  or  with  little  of  either  con- 
denser in  use.  When  the  clicking  or 
squealing  is  noticed,  the  neutralizing 
condenser  should  be  adjusted  in  small 
steps  until  this  clicking  or  whistling  dis- 
appears. The  set  is  then  neutralized. 
This  method  is  both  simple  and  effective, 
although  there  are  others  that  might  be 
employed. 

The  set  now  operating,  the  tickler  coil 
should  be  turned  toward  100  on  its  dial 
until  a  plunk  is  heard,  and  stations  come 
in  again  as  a  whistle.  This  is  entirely 
correct,  as  the  whistle  can  be  cut  out  by 
reducing  the  tickler  coupling.  If  the 
"plunk"  cannot  be  heard,  even  using  45 
volts  on  the  detector  instead  of  22,  the 
two  top  lugs  on  the  vario  coupler  should 
be  reversed. 

In  tuning  the  set,  either  of  two  methods 
may  be  used.  The  first  one  is  to  tune  in 
a  station  with  the  two  condensers,  leaving 
the  tickler  at  zero,  and  then  strengthening 
•  the  signal,  with  the  tickler  when  heard. 
The  second  and  preferable  one  is  to  turn 
the  tickler  up  until  stations  come  in  as  a 
squeal,  rotate  the  detector  condenser 
until  a  squeal  is  heard,  then  vary  the  first 
condenser  for  maximum  intensity,  fol- 
lowing this  by  turning  the  tickler  back 
until  the  squeal  disappears  and  the  sta- 
tion modulation  is  heard.  In  either  case 
final  adjustments  will  have  to  be  made 
on  all  dials  when  receiving  weak  signals. 

If  the  receiver  is  broad  in  tuning,  a 
small  fixed  condenser  connected  in  series 
with  the  antenna  lead-in  will  remedy 
matters.  It  should  be  either  .0001, 
.00025    or  .0005,  mfd    capacity    arranged 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


so  that  it  can  be  short-circuited  by  a 
single-pole,  single-throw  knife  switch 
when  desired. 

If  an  indoor  antenna  is  to  be  used,  it 
may  be  put  up  in  an  attic,  and  should 
consist  of  several  wires  run  parallel  to 
each  other  and  connected  together  at 
both  ends,  or  it  may  be  as  long  a  wire  as 
is  convenient  run  around  a  picture  mould- 
ing. Some  difficulty  may  be  experienced 
en  neutralizing  the  set  on  such  indoor 
antennas,   however. 


(Further  specifications  and  diagrams  con- 
cerning this  receiver  may  be  had  by  sending 
25  cents  in  stamps  to  McMurdo  Silver, 
care  this  magazine.] 


WJJD  Tries  Some  Intentional 
Fading 

What  movie  fan  doesn't  know  what 
a  "fade-out"  is?  And  now  comes  the 
radio  fade-out. 

When  Jack  Nelson  was  at  old  WDAP, 
he  established  the  custom  of  singing  his 
song,  "May  You  Laugh  in  Your  Dreams," 
as  the  finale  to  late  programs,  after  all 
signing  oft  announcements  had  been 
made.  He  does  the  same  now  on  the  late 
programs  of  WJJD,  the  Loyal  Order  of 
Moose  station  at  Mooseheart,  Illinois, 
where  he  is  Director  and  Announcer,  but 
Ralph  Shugart,  the  Engineer  has  added 
the  new  twist  which  is  receiving  many 
comments. 

When  Mr.  Nelson  is  half  way  through 
the  song,  it  begins  to  decrease  in  volume 
until  the  last  notes  of  his  singing  and 
playing  fade  away  into  silence.  The 
effect  is  such  that  the  listeners  feel  they 
are  drifting  into  space.  One  listener  said 
that  the  only  way  he  could  describe  it 
was  to  say,  "It  makes  me  feel  just  as 
though  I  were  dropping  off  to  sleep  in  a 
clover  field  in  the  middle  of  a  drowsy 
summer  afternoon.  Boy,  he  certainly 
gives  me  the  spring  fever!" 


WBBM  Inaugurates  Sunday  Jazz 

A  Tea  Dance  Program  featuring  the 
Dixie  Boys'  Orchestra,  interspersed  with 
popular  numbers  was  heard  from  WBBM 
Sunday,  April  19,  from  four  to  six  p.  m. 
It  has  been  announced  that  tnis  was  the 
beginning  of  a  regular  Sunday  afternoon 
Jazz  Frolic  from  WBBM  to  be  broadcast 
from  their  studio  in  the  Broadmoor 
Hotel,  Chicago. 

The  popularity  of  this  hour  w~as  shown 
by  the  immense  volume  of  'phone  calls 
which  were  received  during  the  program. 
Six  trunk  lines  were  kept  busy  during  the 
entire  program,  and  many  calls  un- 
doubtedly were  missed.  The  next  day's 
mail  was  strong  in  its  praise  of  this 
popular  program,  and  it  would  seem  that 
the  idea  has  made  a  big  hit  with  the 
Sunday  radio  listeners.  Oat  of  all  the 
comments  received,  only  one  criticism 
was  noted,  showing  beyond  much  doubt 
that  the  Sunday  afternoon  listeners  ap- 
proved of  the  idea  of  a  popular  program. 
WBBM  announces  that  hereafter  this 
will  be  a  regular  feature  of  their  Sunday 
afternoon  program,  running  from  four 
to  six  p.  m.  The  Dixie  Boys  Orchestra 
will  be  a  feature  regularly  on  this  program 
as  well  as  popular  artists  of  the  lighter 
music. 


Creative  Lighting  Effects  Feature 
New  WJAZ  Studio 
T^VISTINCTIVE  developments  in  light- 
-L-'  ing  effects  will  play  an  important 
and  unusual  part  in  WJAZ  studio  broad- 
casting from  their  new  location  in  the 
Straus  Building,   Chicago. 

In  1923-4,  the  Zenith  Radio  Corpora- 
tion owned  and  operated  Station  WJAZ 
at  the  Edgewater  Beach  Hotel,  Chicago. 
This  station  was  known  to  the  entire 
radio  world  and  when  Zenith  sold  this 
station,  hundreds  of  thousands  of  letters 
were  received  appealing  to  WJAZ  to  come 
back  on  the  air-.  Although  the  station 
was  sold,  the  call  letters  were  retained 
and  the  radio  listening  public  will  soon 
hear  the  familiar  WJAZ  going  out  over 
the  radio  waves.  These  old  listeners  and 
a  host  of  new  friends  will  again  be  able 
to  hear  the  high  class,  pleasing  programs 
previously  associated  with  Zenith  WJAZ 
broadcasting. 

The  new  studio  will  mark  an  epoch  in 
the  construction  of  radio  broadcasting 
apparatus.  The  entire  23rd  floor  in  the 
beautiful  new  Straus  Building  will  be 
utilized  by  the  studio,  reception  room, 
and  executive  offices  of  the  Zenith  Cor- 
poration. The  studio  architectural  fur- 
nishings will  be  in  Spanish  style  with 
Louis  XVI  period  furniture.  Oriental 
rugs,  heavy  drapes  and  rich  tapestries 
will  further  enhance  the  effect.  Ac- 
coustician  experts  have  arranged  in- 
teriors so  that  the  delicate  pifech  of  the 
violin  and  the  deep  resonant  tones  of  the 
bass  viol  will  all  be  harmoniously  perfect 
in  their  transmission. 

Dr.  M.  Luckiesh,  Director  of  the  Light- 
ing Research  Laboratory,  has  been  secured 
to  plan  and  direct  the  indirect  illumina- 
tion for  this  studio.  Dr.  Luckiesh  is  the 
author  of  books  which  are  generally  ac- 
cepted as  authoritative  works  on  lighting. 

Lights — soft  gradations  of  light  and 
bold,  illuminative  effects,  will  make  the 
atmosphere  of  this  studio  fit  in  with  the 
mood  of  the  selection  being  given  by  the 
artist.  It  has  long  been  a  problem  in 
radio  to  secure  the  proper  settings  for 
artistic  broadcasting.  Many  times  rendi- 
tions of  music  from  broadcasting  stations 
have  been  below  standard.  The  operatic 
stars  on  the  stage  are  surrounded  by  ap- 
propriate settings  which  help  create  in 
them  the  spirit  of  the  character  being 
portrayed,  while  on  the  other  hand,  in  a 
bare  room,  an  invisible  audience  handi- 
caps these  same  artists  in  giving  strength 
and  realism  to  their  selections.  Although 
the  stage  settings  will  not  be  available, 
this  new  thought  in  lighting  will  take  the 
place  of  painted  scenery  and  effect  a 
perfect  rendition. 

Artists  broadcasting  from  this  new 
studio  will  not  experience  that  strange- 
ness associated  with  the  knowledge  that 
they  are  entertaining  vast  audiences,  to 
them  invisible.  An  entirely  novel  and 
new  microphonic  speaker  will  be  part  of 
the  modern  equipment  installed.  This 
speaker  will  be  so  designed  that  by  the  use 
of  motion  picture  photography — an  aud- 
ience is  thrown  on  the  screen  of  the  micro- 
speakaphone  and  is  constantly  before  the 
artist  performing.  Grand  Opera  stars 
have  enthused  over  the  arrangement  and 
have  voiced  their  whole-hearted  approval. 


LIFE, 
LIBERTY 

and  the  Pursuit  of 

HAPPINESS 


You  Wont  Have 
to 

PURSUE 
HAPPINESS 

You  can  have  it  right  at  your  elbow 
to  while  away  the  time  'til  old  Lady 
Static  gets  off  the  line! 

You'll  have  no  trouble  getting 
station  Z-I-F-F-S,  because  you'll 
find  it  is  always  tuned  in  to  catch 
your  funny  bone's  wavelength,  and 
is  more  ticklish  to  your  giggle  box 
than  the  finest  cat  whisker! 

ZIFFS,  Badzib's  Book  of  Art  and 
Wit,  is  the  only  humorous  monthly 
of  its  kind  on  the  market,  and  is 
crammed  full  of  the  best  artists 
and  funsters  in  the  world! 

Exclusive  Photo  Section!  Com- 
plete gallery  of  French-American 
Art  Studies  in  color!  Fifty  pages  of 
illustrations!  Pep,  Ginger,  Punch! 
ALL  FOR  TWO  BITS  I 

Pick  This  Out  On 
Your  Piccolo ! 

Even  tho'  your  set  is  growling 

'Tit  you  think  a  cat  is  howling 
And  the  music  comes  in  walling,  hissing  sniffs. 

You  will  giggle,  grin  and  chuckle 

'Till  you  hafta  loose  the  buckle 
On  your  belt,  if  you've  the  latest  book  of  Z/FFS 

You  wouldn't  go  fishing  without 
bait,  would  you?  Well,  then,  don't 
try  to  get  Hong  Kong  on  a  stormy 
night  with  a  crystal  set,  till  you've 
put  your  John  Henry  on  the  tag 
below: 


ZIFF'S  BUZZARDS  ROOST 
Maywood,  111. 

Dear  Bacbib: 

I  got  a  radio.  I  got  Hawaii.  I  got  drowned 
out.     I  got  peeved. 

I  don't  see  nothin'  to  laugh  at,  you  big  bum! 
Here's  two  bits.  Send  me  the  May  ZIFFS  and 
I  willt 


I   They  Call  Me i 

|   And  I  live  at i 


58 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Some  Progress  Toward  Non- 
Oscillating  Circuits 

By  JOHN  B.  RATHBUN  and  P.  D.  LOWELL 


KNOWING  that  RADIO  AGE  read- 
ers, especially  at  this  time,  when 
sets  are  bing  rebuilt  for  the  Winter 
radio  session,  are  deeply  interested  in  any 
advances  in  the  constrution  of '  tuning 
units  whereby  stabilized  radio  frequency 
amplification  may  become  an  established 
fact,  we  are  printing  two  articles  in  this 
issue  which  should  shed  a  great  deal  of 
light  on  the  subject. 

The  first  is  written  by  John  B.  Rath- 
bun,  well  known  to  our  readers  as  the 
conductor  of  the  blueprint  diagrams  sec- 
tion, a  department  enjoying  well  merited 
popularity.  His  article  is  on  tests  made 
with  a  toroid,  so  constructed  that  its  field 
is  self-contained. 

The  other  article,  more  from  the  manu- 
facturing standpoint,  is  written  by  P.  D. 
Lowell,  research  engineer  with  A.  H  Grebe 
and  Co.,  Inc. 

Both  of  these  writers  have  treated  the 
subject  in  a  concise  and  illuminating 
manner,  so  much  that  we  feel  our 
readers  will  have  no  trouble  in  following 
and  absorbing  the  data  given. 

Balloon  Tires  for  the  Radio  Set 

By   John  B.  Rathbun 

FOR  more  than  a  year  radio  manufac- 
turers have  been  concentrating  their 
attention  on  the  development  of  tuning 
inductances  and  radio  frequency  trans- 
formers, appreciating  the  fact  that  the 
efficiency  and  se- 
lectivity of  a  cir- 
cuit is  no  greater 
than  the  efficien- 
cy of  the  induc- 
tance employed. 
As  a  result,  almost 
numberless  "low- 
loss"  coils  have 
been  placed  on  the 
market  within  the 
last  few  months 
which  possess 
many  points  of 
merit,  but  which 
are  very  similar  in 
general  design  and 
which  from  the 
standpoint  of  the 
magnetic  circuit 
are  really  nothing 
but  refined  edi- 
tions of  the  old 
solenoid  type  coil. 

Dielectric  losses 
have  been  reduced 
to  a  minimum,  dis- 
tributed capacity 
has  made  its  fare- 
well bow  to  the 
radio  pulbic,  but 
little  attention  was 
paid  to  the  stray 
magnetic  fields  set 
up  by  the  coils 
which  still  cause 
trouble  through 
back-coupling  and 
other  inductive 
disturbances. 

Open  magnetic 
circuit  inductances 
of  the  conventional 


Fig.  1 

The  above  is  the  type  of  jieldless  inductance 
described  in  this  article  by  Mr.  Rathbun. 

type,  no  matter  what  their  construction 
may  be,  are  by  their  very  nature  quite 
susceptable  to  stray  magnetic  fields  from 
nearby  broadcasting  stations  or  from 
other  parts  of  the  circuit,  and  therefore 
suffer  from  a  variety  of  undesirable  inter- 
ferences and  couplings  which  reduce  the 
selectivity  and  result  in  disagreeable 
noises.  With  powerful  local  broadcast- 
ing stations,  such  coils  act  as  miniature 
loop  aerials,  picking  up  signals  within 
the  receiving  set  and  making  selectivity 


impossible  Further,  the  solenoid  type 
air  core  transformer  shoots  out  a  magnetic 
field  for  several  feet  around  the  set  which 
may  produce  excessive  regeneration  in 
one  or  more  of  the  radio  frequency  stages, 
with  the  accompanying  howling  and 
shrieking  that  has  been  experienced  by 
all  radio  experimenters. 

All  this  has  been  done  away,  with  by 
the  new  ring-like  inductances  which  are 
variously  known  as  Balloon  Circloids, 
Toroidal  coils,  or  the  Terus,  the  latter 
being  the  geometrical  term  for  a  ring 
having  a  circular  cross-section.  Electric- 
ally, there  is  nothing  new  about  this  form 
of  magnetic  circuit,  but  it  is  decidedly 
novel  in  its  application  to  radio  circuits 
as  a  means  of  eliminating  inductive 
interferences.  Consider  a  long  hollow 
coil  of  wire  wrapped  around  a  circular 
core,  with  its  two  ends  meeting,  and  you 
have  the  Balloon  Circloid  or  Toroid 
which  forms  the  subject  of  this  article. 
With  the  two  ends  of  the  coil  meeting, 
it  is  evident  that  we  can  have  no  poles, 
and  having  no  external  poles,  it  cannot 
produce  nor  be  affected  by  an  external 
magnetic  field. 

Fig.  1  is  a  photographic  view  of  a  new 
zero  field  coil,  and  is  one  of  several  now 
being  produced  for  the  market.  The 
ring-like  coil  is  bent  around  the  center 
core,  which  acts  both  as  a  support  for 
the  coil  and  the  connection  posts  while 
around  the  outer 
periphery  is  a  nar- 
row band  of  insul- 
ating material 
which  stiffens  and 
protects  the  coils 
against  mechanical 
injury.  This  is  a 
two-circuit  trans- 
former or  tuning 
unit  with  a  pri- 
mary and  second- 
ary winding  as  in 
any  coil  used  for 
coupling,  and  can 
be  used  in  any 
radio  frequency  or 
reflex  circuit  as  a 
transformer  and 
tuning  unit.  As 
all  of  the  magnetic 
field  is  within  the 
coil,  there  is  no  di- 
electric loss  due  to 
the  supports,  andit 
is  therefore  a  low- 
loss  coil  in  every 
sense  of  the  word. 
So  far  as  the  coil 
itself  is  concerned, 
it  is  absolutely 
neutral  to  radio 
waves  or  magnetic 
fields,  no  matter 
in  which  direction 
they  may  strike 
the  windings,  and 
the  coil  can  there- 
fore be  crowded 
close  to  other 
inductances  with- 
out coupling  to 
{Turn  to  page  60) 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


59 


2nd  Radio  World's  Fair  to 
Excel  1924  Show 

New  York  City — Practically  all  of  the 
exhibiting  space  in  the  Second  Radio 
World's  Fair  to  be  held  here  in  the  258th 
Field  Artillery  Armory,  September  14to  19, 
is  now  under  reservation  and  even  at  this 
early  date  the  success  of  the  gigantic 
enterprise  is  assured.  All  signs  indicate 
that  it  will  be  the  greatest  trade  show  of 
any  sort  ever  held  in  America. 

Not  only  will  there  be  an  overflow  of 
exhibits  by  the  leading  manufacturers  of 
all  countries,  but  a  record  breaking  at- 
tendance is  already  a  certainty  in  spite  of 
the  fact  that  the  opening  datejs  still  five 
months  away.  Tremendous  interest  is 
being  manifested  by  radio  manufacturers, 
dealers,  inventors  and  enthusiasts  both 
here  and  abroad,  and  the  patronage  is 
sure  to  exceed  that  of  the  First  Radio 
World's  Fair  of  last  September  in  Madi- 
son Square  Garden  and  the  69th  Regi- 
ment Armory. 


The  Echophone  Portable 
Receiver 

An  ideal  portable  receiver  which  com- 
bines high  efficiency  with  light  weight 
and  attractive  appearance.  Takes  up  no 
more  room  than  an  ordinal y  travelling 
bag,  weighing  only  28  lbs.  fullv  equipped 
sixe  9"  x  12V2"  x  18". 

One  of  the  distinctive  features  of  the 
set  is  the  standard  60  foot  aerial  which 
winds  on  a  reel  built  into  the  case.  A 
few  turns  of  the  wrist  and  it  is  ready  for 
use.  For  carrying  purposes  the  aerial 
quickly  winds  back  into  place  and  out  of 
sight.  This  unique  and  complete  aerial 
eliminates  entirely  the  usual  loss  of  vol- 
ume and  efficiency. 

Finished  in  Du  Pont  Leather,  the 
Echophone  Portable  is  in  keeping  with 
the  finest  living  room  appointments,  yet 
it  has  ample  strength  for  severe  vacation 
service.  Available  with  "3"  tube  receiv- 
ing unit  of  exceptional  power.  Range  of 
1,800  to  2,000  miles.  Simple  to  operate 
— only  two  dials  to  tune. 


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are  mounted  in  Bakeiite  bases  designed 
for  use  in  standard  tube  sockets. 
Kit  No.  1 —  40  to  180  meters,  $7.00; 
Kit  No.  2—100  to  300  meters,  $8.00; 
Kit  No.  3 — 224  to  555  meters,  $9.00. 

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THE  fact  that  JeffersonTransform- 
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Proper  amplification — perfect  re- 
production— clear,  undistorted  recep- 
tion; that's  the  why  and  wherefore! 
To  radio  authorities  the  country  over 
Jefferson  means  the  utmost  in  trans- 
former performance. 


Jefferson  Transformers  are  the  re- 
sult of  twenty  years  experience  in  the 
manufacture  of  transformers.To  main- 
tain a  uniform  quality  every  Jefferson 
Transformer  is  subjected  to  a  series 
of  exacting  electrical  and  mechanical 
tests  which  must  be  successfully  pass- 
ed before  leaving  our  hands. 

JeffersonTransformers  meet  match- 
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Jefferson  Electric  Mfg.  Co. 

501 S.  Green  St.  -  Chicago 


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60 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


High  Powered  Broadcasters 
Satisfactory 

WASHINGTON.— There  are  today 
thirty  stations  broadcasting  with 
power  in  excess  of  500  watts,  and  com- 
plaints filed  with  the  Department  of 
Commerce  are  very  few.  On  the  whole, 
the  increased  power  seems  satisfactory 
and  probably  before  the  Summer  is  over 
more  higher-powered  stations  will  be 
operating. 

When  the  question  of  increased  broad- 
casting power  was  raised  during  the 
national  radio  conference,  some  of  the 
smaller  station  owners  and  many  fans 
expressed  the  fear  that  hundreds  of  sta- 
tions would  be  blanketed  or  that  re- 
ceivers would  only  be  able  to  pick  up 
the  high-powered  stations.  This  has 
not  proven  to  be  the  case.  On  the  con- 
trary, broadcasting  seems  to  have  im- 
proved, in  that  more  distant  stations  are 
available  to  listeners,  some  even  tune 
sharper  than  before  the  increase  in  power; 
interference  from  static  has  been  de- 
creased, fading  is  less  pronounced,  and 
davlight  reception  is  better.  Even  the 
fans  situated  near  the  higher-powered 
stations  have  not  complained,  nor  have 
the  regular  A   and    B   stations  objected. 

An  examination  of  the  list  of  thirteen 
stations  using  over  1000  watts,  which 
is  the  ordinary  limit  set  for  Class  B 
stations,  shows  that  four  are  using  2000 
watts,  and  nine,  1500  watts.  Most  of 
the  fans  know  the  calls  of  those  stations 
by  heart,  which  indicates  that  they 
come  in  well  almost  anywhere  in  the 
country  on  good  receiving  sets.  The 
four  2KW  stations  are:  WEAF,  Ameri- 
can Tel.  &  Tel.  Co.,  New  York;  WLW, 
Crosley,  Harrison,  Ohio;  KGO,  General 
Electric  Co.,  Oakland,  Calif.;  and  KFI, 
Earle  C.  Anthony,  Los  Angeles,  Calif. 
Those  using  1500  Watts,  or  \y2  KWS 
are:  .KYW,  Chicago;  WBZ,  Spring- 
field; KFKX,  Hastings;  WGY,  Schenec- 
tady WTAM,  Cleveland;  WOC,  Daven- 
port; WCCO,  Anoko,  Minn.;  WCBD, 
Zion;    and    KOA,    Denver. 

They  are  all  pretty  well  distributed. 
They  are  owned  by  private  organiza- 
tions except  that  three  are  General 
Electric  Co.,  stations,  and  three  are 
owned  by  the  Westinghouse  Electric 
Manufacturing  Co.  The  _  Bell  System 
operates  one,  the  others  being  owned  by 
radio  manufacturers,  and  other  organ- 
izations. It  does  not  seem  to  indicate 
a  radio  monopoly.  The  Radio  Corpora- 
tion is  not  represented  directly,  although 
two  large  electric  manufacturing  com- 
panies control  six  stations  together. 
There  is,  of  course,  another  high-power 
station,  but  it  operates  under  a  rather 
unique  license:  it  is  the  broadcasting 
development  station  KDKA  at  Pitts- 
burgh. This  station,  owned  by  the 
Westinghouse  Co.,  is  licensed  to  use 
varying  power  up  to  10KW  but  ordi- 
narily it  is  understood  to  operate  with 
about  5KW,  except  when  conducting 
special  tests,  usually  when  other  stations 
are   silent.      It   is   never   complained   of. 

None  of  these  stations  is  really  a  super- 
power station,  which  was  decried  as  im- 
practical and  undesirable  when  men- 
tioned at  the  last  radio  conference. 
Before  many  months,  however,  it  is 
expected  that  the  Radio  Corporation 
■will  open  a  very  high  powered  station 
somewhere  outside  New  York  for  national 
broadcasting.  Originally  it  was  intended 
that  it  was  to  be  a  50KW  station,  but 
the  Department  has  never  officially 
stated  this  power  would  be  authorized. 


Balloon  Tires  for  Your  Radio 


( Continued  from  page  51 


them.  It  is  responsive  only  to  currents 
which  are  electrically  connected  to  the 
windings  through  the  binding  posts. 

Interstage  Feed-back 

IX  AX  Y  radio  frequency  or  reflex  circuit 
using  inductances  and  transformers 
of  the  conventional  type,  there  is  always 
some  exchange  of  energy  between  the 
various  radio  stages,  due  to  magnetic 
coupling,  and  if  this  magnetic  coupling 
is  tight  enough,  we  will  produce  audio 
frequency  oscillations  and  counter  oscil- 
lations which  will  interfere  with  reception. 
Feed-back  through  the  grid'  to  plate 
capacity  may  be  easily  suppressed  by 
neutralizing  condensers,  reversed  feed- 
back or  other  devices,  but  it  is  not  such 
an  easy  matter  to  dispose  of  magnetic 
coupling. 

Even  with  the  elaborate  precau- 
tions taken  in  the  neutrodyne  circuits, 
magnetic  coupling  between  stages  is  not 
altogether  avoided  by  placing  the  trans- 
formers at  critical  angles  or  by  neutraliz- 
ing the  grids  The  trouble  will  always 
exist  to  some  extent  as  long  as  there  is  an 
external  field,  and  further,  the  coils  used 
in  such  circuits  are  always  free  to  pick 
up  disturbances,  no  matter  how  they  may 
be  arranged  Up  to  the  present  time  all 
effort  has  been  put  toward  suppressing 
excessive  regeneration  after  it  was  finally 


started,  but  with  the  circloid  the  trouble 
is  eliminated  by  coils  which  do  not  permit 
of  inductive  disturbances  in  the  first 
place. 

Fig.  2  is  a  diagramatic  circuit  of  a 
radio  frequency  set  where  (PI)  and  (SI) 
are  the  primary  and  secondary  of  the 
tuning  unit  (RFT-1),  and  (P2)  and  (S2) 
are  the  primary  and  secondary  coils  of 
the  first  radio  frequency  transformer 
(RFT-2).  The  third  stage  equipment 
does  not  concern  us  at  present.  When 
the  set  is  in  operation,  the  first  R.  F. 
tube  (Tl)  delivers  its  output  to  the  trans- 
former primary  (P2),  and  by  induction, 
energizes  the  secondary  (S2)  which  is 
connected  to  the  second  radio  frequency 
tube  (T2). 

A  powerful  magnetic  field  is  built 
up  around  the  transformer  (T2)  by 
the  plate  current,  and  if  close  enough  to 
the  tuner  unit  (RFT-1),  the  stray  field 
(FB)  indicated  by  the  dotted  lines,  will 
cause  magnetic  coupling  between  the 
tuner  and  transformer.  In  other  words, 
the  coils  (P2-S2)  act  on  the  tuning  coil 
just  like  the  tickler  coil  of  the  regenera- 
tive circuit,  and  may  either  cause  exces- 
sive regeneration  and  howling  in  the  first 
tube  (Tl)  or  cause  counter  impulses 
which  will  act  against  the  incoming 
signals  and  weaken  them.  If  the  inten- 
(  Continued  on  page  63) 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


61 


Standard  Radio  Receivers 


(Continued  from  page  46) 


Craftsmanship  Big  Feature  of  the  Grebe 


A  RECEIVER  that  combines  mechan- 
ical efficiency  with  beautiful  crafts- 
manship of  design  has  been  achieved 
by  the  A.  H.  Grebe  Company,  Rich- 
mond Hill,  N.  Y.,  makers  of  the  Grebe 
Synchrophase  Radio  Receiver. 

This  set  is  distinctive  for  its  appear- 
ance, the  tuning  dials  being  built  horizon- 
tally into  the  set  instead  of  vertically, 
as  is  the  custom  with  most  radio  manu- 
facturers. 

Several  experts  have  found  that 
sharper  and  more  comfortable  tuning  is 
possible  with  controls  of  this  type,  and 
accordingly  the  Grebe  Company  incorpo- 
rated the  idea  when  they  designed  their 
famous  "Synchrophase"  several  years 
ago. 

The  Grebe  Synchrophase  is  a  receiver 


of  the  tuned  radio  frequency  type,  con- 
taining five  tubes.  Greater  sensitivity 
has  been  attained  through  two  stages  of 
balanced  tuned  radio  frequency — the 
result  of  years  of  research.  Extreme 
selectivity  is  achieved  by  the  use  of  the 
popular  binocular  coils,  which  have 
come  into  favor  with  hosts  of  set  builders 
lately. 

The  settings  for  various  broadcasts 
stations  are  equally  spaced  over  the  dials, 
being  accomplished  by  straight-line-fre- 
quency condensers.  The  three  dial 
readings  are  identical  for  a  given  station. 

The  Synchrophase  is  made  in  two 
types,  MU-'l,  for  storage  battery  opera- 
tion, and  MU-2,  for  dry  cell  operation. 
The  price  is  SI 55. 


Only  One  Tuning  Control  with  the  Thermiodyne 


THE  Thermiodyne  6-tube  Tuned 
Radio  Frequency  Receiver  has  as 
its  predominating  feature  one  tuning 
control  for  all  six  tubes. 

The  Thermiodyne  was  one  of  the  first 
commercial  receivers  to  adopt  this  form 
of  tuning  design,  and  it  has  gained  follow- 
ers among  many  fans. 

Furthermore,  this  single  control  is  so 
logged  in  the  factory  that  stations  and 
wavelengths  are  marked  on  the  tuning 
dial,  thus  making  it  possible  to  receive 
stations  immediately  without  any  tire- 
some "fishing." 

No  outdoor  antenna  is  necessary  with 


this  receiver.  Xeither  is  a  directional 
loop  needed. 

The  Thermiodyne  company  also  claims 
that  its  receiver  does  not  squeal,  cannot 
radiate   and   cannot   distort. 

The  circuit  consists  of  three  stages  of 
thermionic  frequency,  detector  and  two 
stages  of  audio  frequency.  Distance  and 
volume  are  very  satisfactory  on  the  loud 
speaker. 

The  single  tuning' control  in  the  center 
ol  the  panel  consists  of  180  degrees. 

The  Thermiodyne  sells  for  $140  and  is 
manufactured  by  the  Thermiodyne  Cor- 
poration of  New  York  City. 


Which  will  survive — the  five  or 
the  six- tube  set  ?  Roscoe  Bundy 
Gives  Some  Real  Reasons  For 
His  Decision — in  July  Radio  Age 
— Out  June  15 


Biggest  dollars 
worth  in 

RADIO 


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boiled  owl.     Contents — 

Electrical  terms  and  circuits,  antennas, 
batteries,  generators  and  motors,  elec- 
tron (vacuum)  tubes,  most  receiving1 
hook-ups,  radio  and  audio  frequency 
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*     Tested  and  Approved  by  RADIO  AGE     * 


62 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Fall  Radio  Conference  Seems 
Probable 

Secretary  Hoover  will  probably  call 
another  national  radio  conference  this 
fall,  in  continuation  of  his  policy  to  hold 
conferences  annually.  The  definite  plans 
and  date  are  as  yet  undecided,  but  it  is 
believed  that  invitations  will  go  out 
calling  the  sessions  in  Washington  in 
November,  certainly  before  Congress 
reassembles. 

Results  secured  at  the  three  past  con- 
ferences have  been  so  valuable  to  the 
Secretary  of  Commerce  that  he  is  dis- 
posed to  refer  all  questions  involving  the 
different  elements  of  the  radio  industry 
and  art  to  a  representative  assembly  of 
all  interests  from  the  manufacturing  and 
commercial  concerns  to  the  amateurs 
and   listeners. 


Paris  Conference  on  September 
First 

The  International  Telegraph  Conven- 
tion scheduled  for  Paris  in  May  has  been 
definitely  postponed  until  September  1, 
according  to  advices  reaching  Washing- 
ton. As  it  is  believed  this  parley  will 
require  at  least  a  month's  time,  following 
which  delegates  will  have  to  return  to 
their  own  countries  to  report  and  for 
further  instructions,  the  International 
Radio  Conference  here  will  probably  not 
be  called  until  after  the  first  of  the  year. 
It  is  probable  that  the  date  will  be  ap- 
proximately in   March  or  April,   1926. 

It  is  understood  that  the  Government 
of  the  United  States  will  be  represented 
at  the  telegraph  conference  by  officials  of 
the  State,  War,  Navy  and  Commerce 
Departments. 


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These  accessories  list  at  $83.50.     If  ordered  with  the    Ultradyne,  the 
price  will  be  only  $53.50. 

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Contains  all  necessary  parts  to  build  the  famous  Freshman 
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sells  for  only  $39.50.     A  solid  walnut  cabinet  may  be  had  for  $7.00. 

See    Our  Ad  in    Last    Month's 
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Trials  and  Triumphs  of  the 
Announcers 

(Continued,  from  page  27) 
The  telephone  rings  and  the  following 
question  comes  from  one  of  our  listeners: 
'Do  I  have  to  listen  to  that  novice  all 
evening?'  A  very  provoking  question  to 
ask  an  announcer  on  such  an  occasion. 
He  was  then  asked  if  he  knew  who  he  was 
listening  to  andafterreplyingin  thenega- 
tive,  he  was  very  politely  told  that  if  his 
set  was  not  working  properly  or  that  if  he 
didn't  appreciate  the  music,  he  was  in 
no  way  obligated  to  keep  on  listening 
the  rest  of  the  evening.  This,  apparently, 
answered  his  first  question  satisfactorily, 
and  was  an  answer  which  fortunately 
savored  very  little  of  the  thoughts  that- 
were  running  through  the  announcer's 
brain. 


the 


The  Fickle  Public 
\  LACK  of  appreciation  for 
-'■■*-  success  of  artists  or  for  the  rep- 
ertoire used  by  them  sometimes  results 
in  requests  which  provoke  a  smile  from 
the  person  to  whom  they  are  addressed. 
When  presenting  a  program  at  KDKA 
recently,  Mrs.  Christine  Miller  Clemson 
who  before  her  marriage  was  one  of  the 
country's  contraltos  and  a  concert  singer 
with  an  enviable  record,  was  requested 
to  sing  the  jazz  number  'Red  Hot 
Mamma.' 

"Perhaps  one  of  the  most  common 
requests  received  is  that  requesting  an 
artist  to  sing  a  particular  number.  In 
spite  of  the  fact  that  there  are  thousands 
of  songs,  a  good  many  listeners  cannot 
quite  understand  why  the  singer  does 
not  have  the  particular  number  they 
request.  Song  pluggers  are  requested 
to  sing  'Arias'  and  grand  opera  stars 
are  requested  to  sing  jazz  numbers  by  the 
well-meaning  audience.  It  also  happens 
quite  often  that  in  spite  of  the  fact  that 
we  receive  hundreds  of  requests  for 
numbers  during  a  particular  evening, 
some  well  meaning  individual  is  at  a 
loss  to  know  why  his  or  her  particular 
request  was  not  granted. 

"Oftentimes  a  party  will  call  and  ask 
the  following  question  or  a  similar  one: 
T  have  a  five-tube  neutrodyne  set  and 
cannot  hear  anything.  Will  you  please 
tell  me  what  is  the  matter  with  my  set?' 
The  opinion  seems  to  be  quite  prevalent 
among  a  good  many  listeners  that  the 
wavelength  determines  the  distance  which 
a  station  can  be  heard,  and  usually  the 
belief  prevails  that  the  distance  a  station 
can  be  heard  varies  directly  with  its 
wavelength.  This  opinion  is  the  cause 
of  some  very  humorous  questions  being 
asked. 

"Among  the  innumerable  questions 
are  such  questions  as  these:  What  time 
is  it?  Where  is  station  WXY  located? 
What  is  the  name  of  the  waltz  the 
band  played  last  Saturday  night?  What 
is  the  wavelength  of  station  WXY? 
How  far  are  you  broadcasting  tonight? 
Who  is  going  to  give  your  program  on 
the  2nd  of  next  month?' 

"And  so  the  announcer  soon  finds 
himself  converted  into  an  information 
bureau  from  which  the  dissemination  of 
news  adds  a  very  colorful  diversion  to 
his  vocation." 


*     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  June,  1925 

The  Binocular  Coil 


The  Magazine  of  the  Hour 


63 


(Continued  from  page  60) 


sity  of  the  stray  feed-back  (FB)  could  be 
controlled,    it    might   be   even    desirable, 
but  as  it  cannot  be  controlled,  it  means 
trouble.      The 
closer  the  two  coils 
and  themore  near- 
ly that  they  are  in 
line,     the     greater 
will    be    the    feed- 
back. 

This  figure  will 
explain  why  many 
radio  frequency 
sets  will  produce 
aerial  radiations 
and  annoy  the 
neighbors  al- 
though a  radio  fre- 
quency set  is  said 
to  be  proof  against 
this  trouble.  With 
the  stray  feed-back 
(FB),  we  have  a 
truly  regenerative  circuit  in  the  first 
stage  which  is  just  as  capable  of  ''tweet- 
tweet-tweeting"  in  a  nearby  receiver  as 
the  most  violent  of  single  tube  ultra-aud- 
ions.  This  condition  at  once  eliminates 
every  advantage  of  an  R.  F.  circuit. 

One  of  the   greatest   advances   in   the 


suppression  of  self-oscillation  was  made 
by  Prof.  Hazeltine  in  the  development  of 
the  Neutrodyne  circuit.  He  not  only 
overcame  the  grid- 
platecapacity  feed- 
back by  means  of 
the  opposing  neu 
tralizing  conden 
sers,  but  he  also 
devised  a  fairly 
effective  method  of 
reducing  the  mag- 
netic inter-linkage 
between  the  radio 
frequency  trans- 
formers which 
helped  a  whole  lot 
in  the  advance- 
ment of  the  radio 
frequency  ampli- 
fier. However,  he 
still  used  the  con- 
ventional solenoid 
strongly  marked 
did     not     entirely 


Fig.  9 


type  open  coil  with 
poles,  and  therefore 
eliminate  magnetic  feed-back.  By  plac- 
ing his  transformer  coils  at  definite 
angles,  he  reduced  the  linkage,  but  of 
course  there  was  always  some  stray  field 
(Continued  on  page  65) 


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Dial  Settings 


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that  come  when  all  dials  read  alike.  Use 
D  U  PLEX  Matched  Condensers — the  s 
prerae  achievement  in  condenser  building. 
Condensers  are  the  "heart"  of  any  set  and 
matched  condensers  are  absolutely  neces- 
sary if  your  set.  is  to  be  free  from  "heart" 
trouble.  DUPLEX  Matched  Condensers  are 
made  in  strict  accordance  with  Bureau  of 
Standards  specifications  for  lowest  losses 
and  best  electrical  characteristics.  They 
are  tested,  matched,  packed  and  sealed  in 
the  laboratory,  to  remain  unopened  until 
ussd.  DUPLEX  Matched  Condensers 
are  used  in  the  famous  Thermiodyne, 
where  matching  is  essential. 
Folder  explaining  how  and  why  matched 
condensers  are  essential  sent  on  request. 
Duplex  Condenser  &  Radio  Corp. 
42  Flatbush  Ave.  Ex.,    Bklyn,  N.  Y. 


* 


ANTENELLA 

No  Aerial  or Antenna  Meeded 

Ihe  Complete 
Efficient  and 
Economical 
Aerial 


Why  pay  $10        Oltllf  H3J 

or  more  to  have  an  aerial  spoil  the 
appearance  of  your  home?  Ante- 
nella  eliminates  all  unsightly  wir- 
ing, lightning  arresters,  etc.,  and 
precludes  the  possibility  of  dan- 
gerous grounding  on  a  power 
line.  It  also  stops  "canary  bird" 
re-radiation  from  nearby  oscillat- 
ing sets  interfering. 

ANTENELLA 

is  not  only  a  real  distance  getter,  but 
also    overcomes    troublesome    6tatic 


At  your  Dealer,  otherwise 
send  purchase  price  and  you 
mil  be  supplied  postpaid. 


f>h  as.  Fresh  man  fo.lnc, 

FRESHMAN   BUILDING 

2*0-248  West  40th  St-NEW  TORK.NY 


*     Tested  and  Approved  by  RADIO  AGE     ¥ 


64 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA 

KDLR 

KDPM 

KDYL 

KDZB 

KDZI 

KFAD 

KFAE 

KFAF 

KFAJ 

KFAN 

KFAU 

KFAW 

KFBB 

KFBC 

KFBE 

KFBG 

KFBK 

KFBL 

KFBU 

KFCB 

KFCC 

KFCF 

KFCL 

KFCZ 

KFDD 

KFDH 

KFDJ 

KFDM 

KFDX 

KFDY 

KFDZ 

KFEC 

KFEK 

KFEL 

KFEQ 

KFER 

KFEY 

KFFP 

KFFR 

KFFV 

KFFY 

KFGB 

KFCC 

KFCD 

KFGH 

KFGQ 

KFGX 

KFHA 

KFHH 

KFHJ 

KFHL 

KFI 

KFIF 

KFIO 

KFIQ 

KFIU 

KFIX 

KFIZ 

KFJB 

KFJF 

KFJ! 

KFJL 

KFJM 

KFJR 

KFJX 

KFJY 

KFJZ 

KFJZ 

KFKA 

KFKB 

KFKQ 

KFKU 

KFKX 

KFLB 

KFLD 

KFLP 

KFLR 

KFLU 

KFLV 

KFLX 

KFLZ 

KFMB 

KFMQ 

KFMR 

KFMT 

KFMW 

KFMX 

KFNF 

KFNG 

KFNJ 

KFNL 

KFNV 

KFNY 

KFOA 

KFOC 

KFOJ 

KFOL 

KFON 

KFOO 

KFOP 

KFOR 

KFOT 

KFOX 

KFOY 

KFPG 

KFPL 

KFPM 

KFPR 

KFPT 

KFPV 

KFPW 

KFPX 

KFPY 

KFOA 

KFQB 

KFOC 

KFOC 

KFOH 

FFOM 

KFOP 

KFOR 

KFOT 

KFOU 

KFQW 

KFQY 

iCFOZ 

KFRC 

KFRM 

KFRN 

KFRU 

KFRW 

KFRX 

KFRZ 

KFSG 

KFSY 

KFUJ 


Westinghouse  Electric  &  Mfg.  Co East  Pittsburgh.  Pa. 

Radio  Electric  Co Devils  Lake.  N.  D. 

Westinghouse   Electric  4   Mfg.   Co Cleveland.   Ohio 

Newhouse    Hotel Salt    Lake    City,    Utah 

Frank    E.    Siefert Bakersfield.    Calif. 

Electric  Supply  Co Wenatchee,  Wash. 

McArthur   Bros.    Mercantile   Co Phoeniz.   Aril. 

State  College  of  "Washington Pullman.   Wash. 

Western   Radio  Corporation Denver.   Colo. 

University  of  Colorado Boulder.  Colo. 

University  of    Idaho Moscow.    Ida. 

Boise  High  School Boise.  Idaho 

The  Radio  Den  (W.  B.  Ashford) Santa  Ana.  Calif. 

F.  A.  Buttrey  4  Co Havre.  Mont. 

W.   K.   Azbill San   Diego.    Calif. 

Horn  4  Wilson's  "Radioland" San  Luis  Obispo.  Calif. 

First  Presbyterian  Church Tacoma.  Wash . 

Kimball-Upson     Co Sacramento.  Calif. 

Leese  Bros ■ Everett,   Wash. 

The     Cathedral Laramie.  Wyo. 

Nielson  Radio  Supply  Co Phoenix.  Ariz. 

The   First   Congregational    Church Helena.    Mont. 

Frank  A.  Moore Walla  Walla.  Wash. 

Leslie  E.   Rice Los  Angeles,   Cal. 

Omaha   Central   High    School Omaha.    Nebr. 

St.     Michaels     Cathedral : Boise.     Idaho 

University  of  Arizona Tuscon.  Ariz. 

Oregon    Agricultural    College Corvallis.    Oreg. 

Magnolia  Petroleum  Co. Beaumont.  Tex. 

First   Baptist   Church Shreveport.    La. 

South    Dakota  State   College Brookings,    S.    Dak. 

Harry    O.    Iverson Minneapolis.    Minn. 

Meier  4  Frank  Co Portland.  Oreg. 

Augsbury    Seminary Minneapolis,    Minn. 

Winner    Radio    Corp Denver.    Colo. 

J.  L.  Scroggin Oak.  Nebr. 

Auto  Electric  Service  Co Fort  Dodge.  Iowa 

Bunker  Hill  4  Sullivan  Mining  and  Concentrating  Co. Kellogg.  Idaho 

First    Baptist    Church _ Moberly.    Mo. 

Nevada  State  Journal  (Jim  Kirk) .  '. Sparks.  Nev. 

Graceland    College Lamoni.  Iowa 

Pincua  A   Murphy  Music  House Alexandria,    La. 

Heidbreder  Radio  Supply  Co Utica.  Neb. 

Louisiana    State    University Baton    Rouge.    La. 

Chickasha  Radio  A  Electric  Co Chickasha.  Okla. 

Leland  Stanford  Lrniversity Stanford  University,  Calif. 

Crary    Hardware     Co Boone,     Iowa 

First   Presbyterian    Church Orange,    Tex. 

Western  State  College  of  Colorado Gunnison.  Colo. 

Ambrose  A.  McCue Neah  Bay.  Wash. 

Fallon   4    Co Santa   Barbara.   Calif. 

Penn     College Oskaloosa.  Iowa 

E.   C.   Anthony,   Inc ■' Los   Angeles.   Calif. 

Benson  Polytechnic  Institute Portland.   Oreg. 

North    Central    High    School ' Spokane.    Wash. 

First   Methodist    Church Yakima.    Wash. 

Alaska  Electric  Light  &  Power  Co Juneau.  Alaska 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints  Independence.  Mo. 
Daily  Commonwealth  and  Oscar  A.  Huelsman Fond  du  Lac.  Wis. 

Marshall    Electrical    Co Marshalltown.    Iowa 

National   Radio  Manufacturing  Co Oklahoma  City.   Okla. 

Liberty  Theatre  (E.  E.  Marsh) Astoria.  Oreg. 

Hardsacg    Manufacturing    Co Ottumwa.     Iowa 

University  of  North  Dakota Grand  Forks,  N.  Dak. 

Ashley   C.   Dixon   4   Son Stevensville.  Mont,    (near) 

Iowa  State  Teacher's  College Cedar  Fall3,  Iowa 

Tunwall   Radio   Co Fort   Dodge.   Iowa 

Texa3  National  Guard,  One  hundred  and  twelfth  Cavalry.Fort  Worth,  Texas 

W.  E.  Branch Fort  Worth    Texas 

Colorado  State  Teachers  College  Greeley,  Colo. 

Brinkley-Jones     Hospital     Association Milford,     Kails. 

Conway  Radio  Laboratories   (Ben   H.  Woodruff) Conway.  Ark. 

The  University  of  Kansas Lawrence.  Kans. 

Westinghouse  Electric  &  Manufacturing  Co Hastings.  Nebr. 

Signal  Electric  Manufacturing  Co Menominee.  Mich. 

Paul    E.    Greenlaw Franklinton.  La . 

Everett    M.    Foster Cedar    Rapids.    la. 

University    of    New    Mexico Albuauerque,  New  Mexico 

Rio  Grande   Radio  Supply   House San   Benito.   Texas. 

Rev.  A.  T.  Frykman Rockford.    HI. 

George  Roy  Clough Galveston,  Tex. 

Atlantio  Automobile   Co Atlantic.    la. 

Christian    Churches Little    Rock.    Ark. 

University  of  Akransas Fayetteville.  Ark. 

Momingside  College Sioux  City,  Iowa 

Dr.    George    W.    Young Minneapolis,    Minn. 

M.  G.  Snteren Houghton.  Mich. 

Carleton  College Northfield.  Minn. 

Henry  Field  Seed  Co Shenandoah.  Iowa 

WootBn's  Radio  Shop Coldwater,  Miss. 

Central  Mo.  State  Teachers  College Warrensburg.  Mo. 

Radio  Broadcast  Ass'n Paso  Robles,  Calif. 

L.  A.  Drake  Battery  and  Radio  Supply  Shop Santa  Rosa.  Calif. 

Montana    Phonograph    Co Helena,  Mont. 

Rhodes     Department    Store Seattle,  Wash . 

First    Christian    Church Whittier.    Calif . 

Moberly  High  School  Radio  Club Moberly,  Missouri 

Leslie  M.  Schafbush : Marengo,  Iowa 

Echophone    Radio   Shop Long  Beach.  Calif. 

Latter  Day  Saints  University Salt  Lake  City,  Utah 

Rohrer  Elec.   Co Marshfield,   Ore. 

David  City  Tire  A  Electric  Co David  City,  Nebraska 

College  Hill  Radio  Club Wichita.  Kansas 

Board  of  Education.  Technical  High  School Omaha,  Nebraska 

Beacon  Radio  Service St.  Paul.  Minn. 

Garretson  and  Dennis Los  Angeles,  Calif. 

C.    C.    Baxter Dublin,  Texas 

The   New   Furniture  Co Greenville.  Texas 

Los  Angeles  Co.  Forestry  Dept Los  Angeles.  Calif. 

Cape  A  Johnson Salt  Lake  City.  Utah 

Heintz  A  Kohlmoos.   Inc San  Francisco,  Calif. 

St.  Johns  M.  E.  Church Carterville.  Mo. 

First  Presbyterian  Church Pine  Bluff.  Ark. 

Svmons  Investment  Co Spokane.  Wash. 

The  Principia St.  Louis.  Mo. 

The  Searchlight  Publishing  Co .    .  .  -Fort  Worth.  Tex. 

Kidd    Brothers    Radio    Shop Taft.    Calif. 

Southern  Calif.  Radio  Ass'n ...  Los  Angeles.  Calif. 

Radio    Service    Co Burlingame.  Calif. 

Texas     Highway     Bulletin Austin.  Tex. 

G.    S.    Carson.    Jr Iowa   City.    la. 

Walter   LaFayette  Ellis Oklahoma    City.    Okla. 

Texas  National  Guard Dennison.  Texas 

W.  Riker Holy  City.  Calif. 

C.  F.  Knierim North  Bend.  Wash. 

Farmers    State    Bank Belden.  Neb. 

Taft    Radio    Co Hollwyood,  Calif. 

City  of  Paris  Dry  Goods  Co San  Francisco.  Calif. 

James  F.  Boland Fort  Sill.  Okla. 

M.  Laurence  Short Hanford,  Calif. 

Etherioal  Radio  Co Bristow,  Okla. 

United  Churches  of  Olympia Olvmpia.  Wash. 

J.  Gordon  Klemgard Pullman.  Wash. 

The  Electric  Shop Hartington.   Neb. 

Angelus   Temple Los    Angeles,    Calif. 

The   Van   Blaricon   Co Helena.    Mont. 

Hopper  Plumbing  and  Heating  Co Breckenridge,  Minn. 


309 
231 
270 
250 
240 
360 
273 
348 
278 
360 
230 
271 
2S0 
360 
278 
218 
250 
283 
224 
283 
238 
248 
256 
236 
258 
252 
368 
254 
315 
360 
360 
231 
248 
261 
254 
268 
231 
233 
266 
226 
280 
275 
224 
254 
248 
273 
226 
250 
252 
261 
360 
240 
468 
248 
252 
242 
226 
240 
273 
248 
252 
252 
242 
280 
258 
280 
246 
254 
254 
273 
286 
250 
275 
288 
248 
234 
256 
254 
236 
229 
240 
273 
254 
299 


266 
336 

266 
254 
234 
240 
214 
261 
384 
236 
246 
234 
234 
261 
240 
226 
231 
248 
226 
23S 
242 
212 
231 
268 
236 
2  68 
242 
283 
2  61 
221 
258 
226 
231 
2  68 
281 
220 
252 
253 
248 
273 
240 
268 
2  63 
224 
391 
220 
217 
222 
272 
261 
242 


KFUL  Thomas  Goggan  A  Bros.  Music  Co Galveston,  Tel.  2S8 

KFUM  W.  D.  Corley Colorado  Springs.  Colo.  242 

KFUO  Concordia     Seminary St.  Louis,  Mo.  S4» 

KFUP  Fitzsimmons  General    lospital Denver,  Colo.  234 

KFUQ  Julius  Brunton  and  Sons  Co San  Francisco.  Calif.  234 

KFUR  H.  W.  Peery  and  C.  Redfield Oeden.  Utah  224 

KFUS  Louis     L.    Sherman Oakland.     Calif.  233 

KFUT  University    of    Utah Salt  Lake  City.  Utah  271 

KFUU  Colburn    Radio    Labs San    Leandro.    Calif.  231 

KFUY  Irvine    M.    Bouchard Butte.  Mont.  254 

KFUZ  Y.  M.   C.  A Virginia.   Minn.  244 

KFVC  Bensberg's  Music  Co Camden,  Arkansas  248 

KFVD  McWhinnie  Electric  Co San  Pedro.  Calif.  202 

KFVE  Film    Corporation   of  America St    Louis,  Mo.  245  - 

KrVF  Clarence  B.   Juneau    Hollywood,   Calif  208 

KFVG  First  M.  E.  Church Independence.  Kansas  236 

KFVH  Whan   Radio  Shop    (Herbert  Whan) Manhattan.   Kansas  218 

KFVI  Headquarters   Troop.   56th    Cavalry Houston     Texas  248 

KFWA  Browning    Bros.    Co Ogden,    Utah  214 

KFWB  Warner  Bros Hollywood.  Calif.  252 

KFWC  L.  E.  Wall  and  C.  8.  Myers Upland.  Calif.  211 

KFWD  Arkansas  Light  &  Power  Co Arkadelphia.  Arkansas  266 

KFWF  St.   Louis  Truth   Center St.  Louis,  Mo.  214 

KGB  Tacoma   Daily  Ledger Tacoma,   Wash.  252 

KGO  General  Electric  Co Oakland,  Calif.  361 

KGU  Marion    A.    Mulrony Honolulu.    Hawaii,    Waikiki   Beach  360 

KGW  Portland   Morning  Orcgoniaa Portland    Oreg  491 

KG Y  St.   Martins  College   (Reb.  Sebastian  Ruth) Lacy,  Wash.  253 

KHJ  Times-Mirror    Co Los    Angeles,    Calif.  405 

KHQ  Louis  Winner Seattle  .Wash.  273 

KJQ  C.    O.    Gould Stockton,    Calif.  273 

KJR  Northwest  Radio  Service  Co Seattle,  Wash.  384 

KJS  Bible  Institute  of  Los  Angeles.  Inc Los  Angeles,  Calif.  293 

KLS  Warner   Brothers    Radio   Supplies    Co Oakland     Calif  242 

KLX  Tribune    Publishing    Co Oakland.    Calif.  508 

KLZ  Reynolds     Radio     Co Denver.  Colo.  283 

ICMJ  San   Joaquin   Light  4   Power   Corp Fresno.   Calif.  243 

KMO  Love    Electric    Co Tacoma.    Waah.  250 

KNX  Los  Angeles  Evening  Express Loa  Angeles.   Calif.  337 

KOA  General    Electric    Co Denver,  Colo.  323 

KOB  New  Mexico  College  of  Agriculture  A  Mechanic  Arts .  State  College.  N.  Mex.  348 

KOP  Detroit    Police   Department Detroit.  Mich .  286 

KPO  Hale    Bros San  Francisco,  Calif.  428 

KPPC  Pasadena  Presbyterian  Church Pasadena,    Calif.  229 

KQV  Doubleday-Hill     Electric     Co Pittsburgh.  Pa.  270 

KOW  Charles  D.    Herrold San  Jose.    Calif.  226 

KRE  V.   C.   Battery  4   Electrio    Co Berkeley,  Calif.  275 

KSAC  Kansas    State   Agricultural   College Manhattan,     Kans.  341 

KSD  Post  Dispatch    (Pulitzer  Pub.  Co.) St.  Louis.   Mo  .  545 

KSL  Radio  Service   Corp.   of  Utah Salt  Lake  City.   Utah  299 

KTHS  New  Arlington  Hotel  Co Hot  Springs.  Ark.  37S 

KTW  First  Presbyterian  Church Seattle.  Wash.  455 

KUO  Examiner  Printing  Co San  Francisco,  Calif.  246 

KUOM  State  University  of  Montana Missoula,  Montana  244 

KWG  Portable    Wireless  ^Telephone    Co Stockton    Calif  248 

K YO  Electrio  Shop Honolulu.  Hawaii  270 

KYW  Westinghouse  Electric  &  Mfg.  Co Chicago    111.  535 

KZM  Preston    D.    Allen Oakland.  Calif.  242 

WAAB  Valdemar    Jensen New    OrleanB.La.  263 

WAAC  Tulano     University New  Orleans  La.  275 

WAAD  Ohio    Mechanics   Institute Cincinnati.  Ohio  248 

WAAF  Chicago   Daily   Drovers  Journal Chicago    111  286 

WAAM  I.    R.    Nelson    Co Newark     N.   J.  263 

WAAW  Omaha    Grain    Exchange Omaha.  Nebr.  285 

WABA  Lake  Forest  University Lake  Forest  111..  227 

WABB  Harrisburg    Sporting    Goods    Co Harrisburg,  Pa.  266 

WABI  Bangor  Railway  A  Electric  Co Bangor,  Me.  240 

WABL  Connecticut    Agricultural    College Sorrs.Conn.  283 

WABM  F.  A.  Doherty  Automotive  and  Radio  Equipment  Co Saginaw    Mich.  254 

WABN  Ott  Radio,    Inc LaCrosse.  Wis.  244 

WABO  Lake  Avenue  Baptist  Church Rochester.  N.  Y.     283 

WAB  Q  Haverford  College.   Radio  Club Haverford.  Pa.  261 

WABR  Scott  High  School.  N.  W.  B.  Foley Toledo.  Ohio  270 

WABU  Victor  Talking  Machine   Co Camden.    N.  J.  224 

WABW  College  of  Wooster Wooster.  Ohio  234 

WABX  Henry    B.   Joy Mt.    Clemens.    Mich.  270 

WABY  John   Magaldi.  Jr Philadelphia.  Pa.     242 

WABZ  Coliseum  Place  Baptist  Church New  Orleans.  La.     263) 

WADC  Allen  T.  Simmons   (Allen  Theatre) Akron.  Ohio     258 

WAFD  Albert  B.  Parfet  Co Port  Huron.  Mich.     233 

WAHG  "  A.  H.  Grebe  4  Co Richmond  Hill,  N.  Y.     315 

WAMD     Hubbard  and  Co Minneapolis.  Minn.     244 

WBAA  Purdue     University W.  Lafayette.  Ind.     283 

WBAC  Clemson  Aerie.  College Clemson  College,  B.C.     331 

WBAH  The    Dayton    Co Minneapolie,  Minn.      417 

WBAK  Pennsylvania  State  Police Harrisburg,  Pa.  275 

WBAN  Wireless   Phone    Corp Patereon,   N.   J.     244 

WBAO  James     Millikan     University Decatur,   111.     360 

WBAP  Wortham-Carter  Publishing  Co.  (Star  Telegram) Fort  Worth.  Tex.     478 

WBAV  Emer  4  Hopkins  Co Columbus.   Ohio     292 

WBAX  John  H.  Stenger.  Jr Wilkes-Barre.  Pa.     254 

WBAY  Western   Electric  Co New  York.N.Y.     492 

WBBG  Irving  Vermilya Mattapoisett,  Mass.      248 

WBBH  J.  Irving  Bell Port  Huron.  Mich.     248 

WBBL  Grace    Covenant    Presbyterian    Church Richmond.  Va.     253 

WBBM  H.  Leslie  Arlass Chicago.   HI.     228 

WBBN  Blake.  A.  B Wilmington,  N.  C.     275 

WBBP  Petoekey  High  School Petoekey.    Mich.     248 

WBBR  Peoples  Pulpit  Asso RossvUIe,  N.  Y.     273 

WBBS  First    Baptist  Church New  Orleans.  La.      252 

WBBU  Jenks    Motor    Sales  Co Monmouth.  111.     224 

WBBV  Johnstown     Radio     Co Johnstown,  Pa.     245 

WBBX  Ruffner    Junior    High    School Norfolk  Va.     222 

WBBY  Washington    Light   Infantry   Co.    "B"    118th    Inf Charleston.  S.  C.     268 

WBBZ  Noble   B.   Watson Indianapolis.   Ind.     227 

WBCN  Foster  4  McDolond Chicago.  111.     268 

WBDC  Baiter  Laundry  Co Grand  Rapids.  Mich.      256 

WBES  Bliss  Electrical  School Takoma  Park  Md.     222 

WBGA  Jones  Elec.  &  Radio  Mfg.  Co Baltimore  Md.     254 

WBOQ  A.  H.  Grebe  &  Co..  Inc Richmond  Hill,  N.  Y.  236 

WBR  Pennsylvania     State     PoUce Butler.  Pa.      286 

WBRE  Baltimore  Radio  Exchange Wilkes-Barre.  Pa.      231 

WBS  D.    W.    May.    Inc Newark  N.J.     252 

WBT  Southern    Radio   Corp Charlotte.  N.  C.     275 

WBZ  Westinghouse  E.  4  M.  Co Springfield.  Mass.      333 

WCAD  St.  Lawrence  University Canton.  N.  Y.     280 

WCAE  Kaufmann    4  Baer  Co.   and  1  he  Pittsburgh  Pres Pittsburgh.  Pa.     461 

WCAG  Clyde  R.  Randall New  Orleans.  La.     262 

WCAH  Entrekin  Electric  Co Columbus.  Ohio     288 

WCAJ  Nebraska  Wesleyan  University University  Place.  Nebr.     283 

WCAL  St.    Olaf    College Northfie'd.  Minn.  338 

WCAO  Sandere  4  Stavman  Co Baltimore  Md.     275 

WCAP  Chesapeake  A  Potoma  Telephone  Co Washington.    D.  C.  468 

WCAR  Alamo  Radio  Electric  Co San  Antonio,  Tex.     263 

WCAS  W.  H.  Dunwoody  Industrial  Institute Minneapolis.  Minn.     280 

WCAT  State  College  of  Mines Rapid  City.  8.  Dak.     240 

WCAU  Durham    &    Co Philadell.hia.Pa.  278 

WCAX  University  of  Vermont Burlington .  Vt .  250 

WCAZ  Carthage    College Carthage. 111.  246 

WCBA  Charles  W.  Heibachm Allentown.  Pa.  280 

WCBC  University  of  Michigan Ann  Arbor.   Mich.  280 

WCBD  Wilbur     C.     Voliva Zion.  111.  344 

WCBE  Uhalt    Radio    Co New   Orleans. La.  263 

WCBF  Paul  J.  Miller Pittsburgh. Pa.  23S 

WCBG  Howard    S.    Williams    (Portable) Pascagoula.  Miss.  268 

WCBH  University    of    Miss Oxford. Miss.      242 

WCBI  Nicol!.    Duncan    4     Rush .Bemis.  Tennessee     240 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


65 


Developments  Toward  Non- 
Oscillating  Circuits 


(Continued  from  page  63) 


which  could  not  be  conquered,  and  he  de- 
pended upon  his  neutralizing  scheme  to 
stop  such  oscillations  as  might  be  started 
magnetically.  In  short,  all  attempts  up 
to  a  very  recent  date  have  been  toward 
suppressing  oscillations  after  they  had 
started  rather  than  prevent  their  forma- 
tion. 

Magnetic  Fields 

A  MAGNETIC  field  is  set  up  around 
any  conductor  that  carries  an  elec- 
tric current,  and  conversely,  an  electric 
current  is  set  up  in  the  conductor  when 
it  is  "cut"  at  right  angles  by  a  moving 
magnetic  field.  This  is  illustrated  by 
Fig.  3  where  (Tl)  is  an  air  core  solenoid 
coil  with  an  electric  current  passing 
through  the  turns  of  wire  wound  on  the 
tube.  Magnetic  lines  of  force  or  the 
"field"  (b)  are  established  by  the  current 
for  a  considerable  distance  around  the 
coil,  and  any  conductor  within  the  area 
embraced  by  the  curved  lines  will  be 
magnetically  affected.  When  carrying 
high  frequency  radio  currents,  the  effects 
of  the  field  may  be  sometines  detected 
for  several  feet  from  the  coil,  particularly 
in  the  direction  of  the  axis  (d).  At  each 
end  are  the  magnetic  poles  marked  (N) 
and  (S),  which  with  direct  current  are 
the  "north"  and  "south"  poles. 

Now  let  us  say  that  the  source  of 
current  is  disconnected  from  the  coil,  and 
that  some  type  of  current  indicator  such 
as  a  voltmeter  is  connected  across  the 
ends  of  the  coil  as  at  (V)  in  dotted  lines. 
If  a  magnetic  field  or  radio  wave-front 
(a)  now  advances  and  cuts  through  the 
coil  along  the  axis  in  the  direction  of  (a), 
a  current  will  be  "induced"  in  the  coil, 
and  the  current  indicator  (V)  will  be 
deflected  as  long  as  the  magnetic  field 
moves  in  respect  to  the  wire.  If  (a)  is  a 
rapidly  oscillating  radio  wave-front, 
then  oscillating  currents  will  be  induced 
in  the  coil  continuously  as  long  as  the 
field  continues. 

Now  let  us  consider  the  second  coil  (T2) 
in  Fig.  4  which  has  been  set  up  at  right 
angles  to  the  first  coil  (CI),  and  in  line 
with  the  magnetic  flux  (d).  As  the  field 
(d)  now  acts  along  the  wires  instead  of 
at  right  angles  to  them,  practically  no 
current  will  be  induced  in  the  wire  of 
(T2).  Similarly  a  radio  wave-front  (C) 
will  induce  no  current  as  long  as  it  travels 
exactly  in  line  with  the  conductors.  In 
practice,  however,  there  will  be  a  little 
induced  current  for  the  reason  that  the 
flux  travels  in  curved  lines  instead  of 
along  a  stright  line,  and  for  the  reason 
that  the  turns  of  wire  are  curved  helices 
and  not  straight.  In  other  words,  the 
magnetic  flux  cannot  ever  be  exactlj' 
parallel  to  the  wire,  and  there  will  always 
be  some  component  that  will  travel  at  an 
angle  to  the  wire. 

Fig.  5  shows  the  actual  conditions  very 
clearly  when  two  coils  are  placed  end  to 
end  or  axially  in  line,  so  that  the  magnetic 
flux  from  coil  (1)  cuts  through  the  length 
of  coil  (2).  The  black  dots  on  Coil  (1) 
indicate  current  carry  supply  wires,  while 
the  open  circles  on  Coil  (2)  are  wires 
carrying  induced  currents.  An  arrange- 
ment of  this  sort  is  absolutely  impractic- 
able in  a  radio  set,  for  the  flux  may  travel 
as  far  as  two  or  three  feet  from  Coil  (1) 
and  induce  currents  or  cause  regeneration 
in  the  circuit  of  Coil  (2).  It  is  also  bad 
practice  to   place   a   metal   plate  in   this 


field  as  shown  at  the  left  by  "Pit."  The 
magnetic  flux  will  induce  eddy  currents 
in  the  plate  and  cause  other  trouble. 

Placing  the  coils  at  right  angles  is  of 
great  assistance,  but  does  not  entirely 
prevent  back-coupling  in  strong  fields. 
Besides  the  magnetic  coupling  there  will 
also  be  electro-static  coupling  due  to  the 
condenser  effect  between  the  coils,  if 
they  are  very  close  together.  With  (D) 
equal  to  as  much  as  12  inches,  there  will 
be  a  very  perceptable  coupling. 

Standard  radio  frequency  practice  with 
solenoid  type  transformers  is  shown  by 
Fig.  6,  this  arrangement  being  originally 
devised  by  Prof.  Hazeltine  for  use  in  the 
Neutrodyne  circuit.  The  transformers 
are  mounted  at  an  angle  of  51°-04',  and 
are  spaced  apart  by  the  center  to  center 
distance  (M)  until  the  adjacent  faces 
(M)  and  (n)  of  the  two  coils  are  sepa- 
rated by  the  distance  (b).  The  lat- 
ter spacing  prevents  electrostatic  coup- 
ling between  the  two  ceils  for  the 
coils  no  longer  face  each  other.  The 
angle  chosen  is  such  that  the  stray 
magnetic  flux  induces  as  little  current  as 
possible,  the  curvature  of  the  lines  of 
force  being  nearly  parallel  to  the  turns 
of  wire  under  these  conditions.  However, 
there  will  always  be  some  coupling  as 
indicated  by  the  curved  flux  lines.  It 
can't  be  avoided  as  long  as  there  is  an 
external  field. 

The  Circloid  Field 

\  T  LAST  we  are  at  the  point  where 
r\.  we  can  appreciate  the  advantages 
of  the  circloid  transformer  coil,  the  coil 
without  an  external  field.  A  pair  of 
sectional  views  of  this  coil  are  shown  in 
Fig.  7  which  will  explain  the  path  of  the 
flux  and  the  low  leakage  coefficient  and 
also  Its  indifference  to  stray  fields  from 
other  coils  or  from  random  aerial  action. 
In  effect,  this  is  simply  an  ordinary  sole- 
noid bent  around  a  circle  having  a  dia- 
meter (F),  the  coil  diameter  being  (d) 
and  the  external  diameter  (D).  Each 
round,  black  dot  represents  a  wire  in 
section  as  at  (W).  The  wires,  of  course, 
are  spaced  farther  apart  on  the  outer 
circumference  than  around  (D)  so  that 
the  inner  circle  appears  almost  like  a 
solid  black  line. 

Inside  the  coil  will  be  seen  the  arrows 
indicating  the  path  of  the  magnetic  flux 
which  in  all  cases  faithfully  follows  the 
outline  of  the  wire  strands.  The  flux  of 
one  wire  tends  to  start  out  tangentially 
to  the  circle  along  a  straight  line,  but  is 
pulled  back  into  place  by  the  influence 
of  the  next  turn  so  that  the  main  portion 
of  the  flux  is  within  the  conductor  area. 
There  is  no  end  and  hence  no  definite 
polarity  is  indicated  at  any  point  that 
would  induce  external  leakage. 

Now  let  the  arrow  (a)  at  the  left  of  the 
figure  represent  a  stray  field  or  the  wave- 
front  from  a  local  broadcasting  station 
travelling  toward  the  coil.  As  such  a 
wave  embraces  the  entire  coil,  it  will 
induce  no  current  for  the  turns  in  the 
upper  half  run  in  the  opposite  direction 
to  those  in  the  lower  half,  and  therefore 
all  induced  charges  oppose  each  other  so 
that  no  current  can  flow.  In  other 
words,  we  will  suffer  no  interference  from 
the  coil  considered  as  an  aerial.  Taking 
the  right  hand  view,  we  see  that  the 
advancing  wave-front  (C)  moving  at 
(Tarn  to  page  67) 
*     Tested  and  Approved  by  RADIO  AGE     * 


OLD  MAN  STATIC 
"KILLED"  AT  LAST 


Statichoke    Has    Startled   the    Radio 
World — Insures  Clear,  Long  Dis- 
tance,    Summer    Reception. 


The  long  promised  invention  which  insures  clear, 
long  distance,  "summer  radio"  without  the  agony 
of  static,  has  just  been  announced.  Radio  experts 
and  fans  who  have  tested  this  new  imported  inven- 
tion pronounce  it  marvelous.  Awarded  Certificate 
of  Merit  by  Radio  News  of  Canada. 

In  addition  to  reducing  static  to  a  minimum,  the 
Statichoke  increases  the  volume  as  well  as  clarity 
of  distant  reception,  sharpens  the  selectivity  of 
tuning  in,  eliminates  that  harshness  of  the  tubes  so 
noticeable  on  local  loud  speaker  reception  and  acts 
as  a  safety  lightning  arrester. 

The  Statichoke  somewhat  resembles  a  small 
transformer,  and  by  a  system  of  coils  it  allows  only 
the  correct  current  value  to  enter  the  set.  choking 
out  other  high  current  variation  from  the  aerial, 
which  is  passed  off  throguh  a  secondary  ground 
connection. 

So  confident  are  the  American  distributors  ihat 
Statichoke  will  give  you  clear  long  distance  summer 
reception  that  they  have  set  aside  25,000  units  for 
initial  distribution  direct  to  the  radio  fans,  at  a 
special  price  of  only  $2.50  each. 

If  interested  write  today  to  Radio  Dspt.,  Im- 
perial Laboratories,  9575  Coca  Cola  Bldg.,  Kansas 
City,  Mo.,  and  the  Statichoke  will  be  sent  you  bv 
insured  mail.  Write  today  as  this  is  a  special  offer 
and  may  not  appear  again. 


memoir 

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66 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


WCBJ  J.  C.   Mails Jennings.  Louisiana  244 

WCBL       Northern   Radio  Mfg.  Co Houlton.  Mo.  280 

WCBM  Charles    Swsrz Baltimore.  Md.  229 

WCBN  James  P.  Boland Ft.  Beni.  Harrison,  Ind.  266 

WCBQ  First    Baptist    Church Nashville  .Tenn.  236 

WCBR  C.  H.  Messter Providence,  R.  I.  24g 

WCBT  Clark    University.    CoUegiate    Dent Worcester,    Mass.  238 

WCBU  Arnold     Wireless     Supply     Co Arnold,     Pa.  254 

WCBX  Radio  Shop  of  Newark   (Herman  Lubinsk, ) Newark,   N.J.  233 

WCBY  The  Forks   Eectrical  Shop Buck   Hill  Falls.    Pa.  268 

WCBZ  Neutrowound  Radio  Mfg.  Co Chicago  Heights.  HI.  217 

WCCO  Washburn-Crosby   Co Twin    Cities.    Minn.  416 

WCEE  Charles    E.    Erbstein.    Villa    Olivia near    Elgin.    111.  278 

WCK  Stii-Baer-Fuiler    D.    Q.    Co St.    Louis.    Mo.  275 

WCX  Free  Press Detroit,  Mich.  516 

WDAE  Tampa  Daily  Times Tampa,  Fla.  365 

WDAF  Kansas    City    Star Kansas    City,    Mo.  365 

WDAG  J.    Laurence    Martin Amarillo.  Tex.  263 

WDAH  Trinity     Methodist     Church      (South) El     Paso.     Tex.  268 

WDAR  Lit  Brothers ' Philadelphia,  Pa.  394 

WDAY  Radio    Equipment    Corp Fargo.  N. Dak.  244 

WDBA  FredRay Columbus,  Ga.  236 

WDBB  A.  H.  Waite&  Co..  Inc Taunton,  Mass.  229 

WDBC  Kirk.    Johnson    &    Co Lancaster.    Pa.  258 

WDBD  Herman  Edwin  Burns Martinsburg.  W.  Va.  268 

WDBE  Gilham-Schoen  Elcc.  Co Atlantic.Ga.  278 

WDBF  Robert  G.  Phillips .Youngstwn,    Ohio  315 

WDBH  C.  T.  Scherer  Co Worcester,  Mass.  268 

WDBJ  Richardson  Wayland  Electric  Corp Roanoke,  Va.  229 

WDBK  M.  F.  Broz Cleveland.  Ohio  227 

WDBL  Wise.    Dept.    of    Markets Stevens  Point.  Wis.  278 

WDBN  Electric    Light  &  Power    Co Bangor.  Me.  252 

WDBO  Rollins    College    Inc Winter  Park,  Fla.  240 

WDBP  Superior  State  Normal  School Superior,  Wis.  261 

WDBQ  Morton  Rado  Supply  Co Salem.  N.J.  234 

WDBR  Tremont    Tomp.e    Baptist    Church Boston,    Mass.  256 

WDBS  S.  M.  K.  Radio  Corp Dayton,  Ohio  283 

WDBT  Taylor    Book    Store Hattiesburg,  Miss.  236 

WDBV  The  Strand  Theatre Fort     Wayne,     Ind.  258 

WDBW  The    Radio    Den Columbia.  Tenn.  268 

WDBX  Otto  Baur New  York.  N.  Y.  233 

WDBY  North    Shore    Congregational    Church Chicago.    III.  258 

WDBZ  Boy  Scouts,  City  Hall Kingstown.  N.  Y.  233 

WDM  Church  of  the  Covenant Washington.  D.  C.  234 

WDOD  Chattanooga  Radio  Co.,  Inc Chattanooga,  Tenn.  256 

WDWF  Dutee  Wileos  Flint.  Inc Cranston,  R.  I.  441 

WDZ  J.    L.    Bush Tuscola.    IU.  278 

WEAA  F.  D.  Fallain Flint,  Mich.  250 

WEAF  American  Telephone  &  Telegraph  Co New  York.  N.Y.  485 

WEAH  Wichita  Board   of   Trade Wichita,    Kans.  280 

WEA!  Cornell     University Ithaca.  N.  Y.  286 

WEAJ  University  of  South   Dakota Vermilion,  S.  Dak.  283 

WEAM  Borough  of  North  Plainfield  (W.  Gibson  Buttfield) ..  North  Plainfield.  N.  J.  286 

WEAN  Shepard    Co Providence,    R.    I.  273 

WEAO  Ohio    State    University Columbus.  Ohio  293 

WEAP  Mobile  Radio  Co Mobile.  Ala.  263 

WEAR  Goodvear    Tire    and    Rubber    Co Cleveland.  Ohio  389 

WEAU  Davidson    Bros.  Co Sioux  City.  Iowa  275 

WEAY  Iris  Theatre  (Will  Horowitz.  Jr.) Houston .  Texas  270 

WEB  BenwoodCo St.  Louis.  Mo.  273 

WEBA  Electric  Shop Highland  Park.   N.  J.  233 

WEBC  Walter  Cecil  Bridges Superior.  Wis.  242 

WEBD  Electrical  Equipment  and  Service  Co Anderson.  Ind.  246 

WEBE  Roy  W.  Walker Cambridge.  Ohio  248 

WEBH  Edgewater  Beach  Hotel. Chicago  Evening  Post  Station Chicago. III.  370 

WEBJ  Third  Avenue  RaUway  Co '.. New  York.    N.Y.  273 

WEBM  Radio    Corporation    of    America Portable  226 

WEBP  E.B.Pedicord New  Orleans.  La.  280 

WEBT  The  Davton  Coop.  Industrial  High  School Dayton.   Ohio  270 

WEBW  Bolrat  College Beloit  Wis.  283 

WEBY  Hobart  RadioCo Roslindale.  Mass.  226 

WEEI  The  Edison  Electric  Illuminating  Co Boston.  Mass.  475 

WEMC  Barrien  Springs.  Mich.  285 

WEN  R  All-American   Radio  Corporation Chicago.   Illinois  266 

WEW  St.     Louis     University St.  Louis.  Mo.  280 

WFAA  Dallas    News    &.    Dallas    Journal Dallas,    Tel.  472 

WFAM  Times  Publishing  Co St.  Cloud.  Minn.  273 

WFAV  University  of  Nebraska,  Department  of  Electrical  Engineering,  Lincoln,  Nebr.  275 

WFBB  Eureka    College Eureka.    111.  240 

WFBC  First     Bapitist     Church Knoxville.  Tenn.  250 

WFBD  Gethsemane  Baptist  Church Philadelphia.  Pa.  234 

WFBE  John  Van  De  Walle Seymour,  Ind.  226 

WFBG  The  Wm.  F.  Cable  Co Altoona.  Pa.  261 

WFBH  Concouree  Radio  Coporation New  York.  N.Y.  273 

WFBJ  St  John's  University Collegeville.  Minn.  236 

WFBQ  Wynne  Radio  Co Raleigh.  N.  C.  255 

WFBR  Fifth  Inf.  Md.  Nat'1  Guard.  5th  Reg.  Armory Baltimore,  Md.  452 

WFBT  Gloucester    Co..    Civic    League Pitman,    N.    J.  231 

WFBW  Ainsworth-Gates  Radio  Co Cincinnati.  Ohio  309 

WFBY  SignalOfficer Ft.  Ben  Harrison.  Ind.  258 

WFBZ  Knox  College Galesburg.  HI.  254 

WFI  Strawbridge  and  Clothier Philadelphia.  Pa.  394 

WFKB  Francis  K.  Bridgmau Chicago.  III.  217 

WFUV  G.Pearson  Ward Springfield.  Mo.  252 

WFUW  Earl  William  Lewis Moberly.  Mo.  233 

WGAL  Lancaster  Electric  Supply  &  Construction  Co Lancaster.  Pa.  248 

WGAQ  YoureeHotel Shreveport.  La.  252 

WGAZ  South  Bend  Tribune * South  Bend.  Ind.  360 

WGBB  Harry  H.  Carman,  217  Bedell  St Freeport,  N.  Y.  244 

WGBC  First  Baptist   Church Memphis.   Tenn.  266 

WGBF  Fink    Furniture    Co Evansville.  Ind.  217 

WGBG  Brietenbach's    Radio   Shop Thrifton.    Va.  226 

WGBH  Fall  River  Herald  Pub.  Co (Portable)  209 

WGBI  Frank  S.  Mcgargee Scranton.  Pa.  240 

WGBK  Lawrence  Campbell Johnstown.  Pa.  248 

WGBM  Theodore  N.  Saaty Providence,  R.  I.  234 

WGBN  Hub     Radio    Shop LaSalle,  111.  266 

WGBO  Dr.  Roses  Artan San  Juan.  P.  R.  275 

WGBL  Elyria  Radio  Asso.  (Albert  H.  Ernst) Elyria.  Ohio  227 

WGBQ  Stout  Institute Menominee,  Wis.  234 

WGBR  Marshfield  Broadcasting  Assn Marshfield.  Wis.  229 

WGBS  Gimbel  Brothers New  York,  N.  Y.  315 

WGBT  Furman    University Greenville,  S.  C.  236 

WGBW  Valley    Theater Spring    Valley.     TIL  212 

WGBX  University  of  Maine Orono.  Me.  252 

WGBY  Progress  Sales  Co R.  R.  No.  2  218 

WG!  American  R.  &  R.  Co Medford  Hillside.  Mass.  261 

WCN  The    Tribune    Co Chicago.    HI.  370 

WGR  Federal  T.  and  T.  Co ' Buffalo,  N.  Y.  319 

WGY  General    Elec.    Co Schenectady  N.  Y.  379 

WHA  University    of    Wisconsin Madison.    Wis.  535 

WHAD  Marquette  University Milwaukee,  Wis.  280 

WHAG  University   of   Cincinnwti Cincinnati.   Ohio  222 

WHAH  Hafer  Supply  Co Joplin,  Mo.  283 

WHAM  University  of  Rochester  (Eastman  School  of  Music) Rochester.  N.  Y  278 

WHAP  H.  Alvin  Simmons.  290  Flatbush  Ave Brooklyn,  N.  Y.  240 

WHAR  Seaside  House Atlantic  City,  N.  J.  275 

WH  AS  Courier-Journal  &  Louisville  Times Louisville.    Kv.  399 

WHAV  Wilmington  Electrical  Specialty  Co Wilmington.   Del.  360 

WHAZ  Rensselaer  Polytechnic   Institute Troy.  N.  Y.  3S5 

WHB  Sweeney    School    Co Kansas    City.    Mo.  365 

WHBA  C.   C.   Shaffer On  City,   Pa.  250 

WHBB  Hobel's   Store Stevens  Point,   Wis.  240 

WHBC  Rev.  E.  P.  Graham Canton.  Ohio  245 

WHBD  Chas.  W.  Howard BeUefontaine,  Ohio  222 

WHBF  Bearrlsley  Specialty  Company Rock  Island,  Illinois  222 

WHBG  John    S.    Skane Harrisburg,    Pa.  231 

WHBH  Culver    Military    Academy Culver.    Ind.  222 

WHBI  Chesanine    Electric    Co Chesaning.    Mich.  227 

WHBJ  Lauer  Auto  Co Ft.  Wayne.  Ind.  234 

WHBK  Franklin   St.    Garage.   Inc Ellsworth.    Maine  231 

WHBL  James  H-  Slusser Logansport.  Ind.  220 

WKBM  C.  L.  Carroll.  Portable  Station Chicago.  HI.  233 

WHBN  First   Ave.    Methodist   Church St.   Petersburg.    Florida  258 


WHBO  Y.  M.  C.  A..  Summer  Street Pawtucket.  Rhode  Island  231 

WHBP  Johnstown  Automobile  Co Johsntown,  Pennsylvania  256 

WHBQ  St.  John's  M.  E.  Church  South Memphis.  Tenn.  233 

WHBR  Scientific  Electriocr  Mfg.  Co.,  30G4  Vine  St Cincinnati,  Ohio  216 

WHBS  Edward  Wm.  Locke : Mechanicsburg,  Ohio  208 

WHBT  Thomas  W.  Tizzard,  Jr Downers  Grove.   HI.      206 

WHBU  B.   L.   Bing's   Sons Anderson,   Ind.     218 

WHBV  Fred  Ray's  Radio  Shop Columbus.  Ga.  244 

WHBW  D.    R.     Kienzle Philadelphia, Pa.  215 

WHBX  J.    W.   Bowser Punxsutawney,   Pa.  213 

WHB  Y  St.    Norbcrt's  College West  De  Pore.  Wis.     250 

WHEC  Hickson  Electric  Co.,  Inc '. Rochester.  N.  Y.  258 

WHK  Radiovox  Company Cleveland. Ohio     273 

WHN  George  Schubert New  York,  N.Y.      360 

WHO  Bankers'  Life  Co Dea  Moines, la.  526 

WIAD  Howard   R.   Miller Philadelphia.   Pa.  254 

WIAK  Journal-Stockman  Co Omaha.  Nebr.  273 

WIAQ  Chronicle    Publishing    Co Marion. Ind.  226 

WIAS  nome  Electric  Co Burlington.  Iowa  283 

WIBA  The    Capital-Times    Studio Madison, Wis.     236 

WIBC  L.  M.  Tate  Post,  No.  39.  Veterans  of  Foreign  Wars St.  Petersburg,  Florida  222 

WIBD  X-L  Radio  Service Joliet,  Illinois  200 

WIBE  Martinsburg  Radio  Broadcasting  Co Martinsburg.  W.  Va.  210 

W1BF  S.  P.  Miller  Dance  Activities Wheatland.  Wise.  231 

WIBG  St.  Paul's  Protestant  Episcopal  Church Elkins   Park.   Pa.  222 

WIBO  Nelson  Brothers Chicago,   IU.  226 

WIL  Continental  Electric  Supply  Co Washington,  D.  C.  360 

WIP  Gimbel    Bros Philadelphia,    Pa.     509 

WJAB  American    Electric    Co Lincoln,    Nebr.  229 

WJAD  Jackson's   Radio   Engineering   Laboratories Waco,    Texas     352 

WJAG  Norfolk  Daily  News Norfolk.  Nebr.     283 

WJAK  Clifford   L.    White Greentown.   Iowa  254 

WJAM  D.  M.  Perham Cedar  Rapida,  Iowa     268 

WJAR  The  Outlet  Co.  (J.  Samuels  *  Bro.) Providence,  R.  I.  306 

WJAS  Pittsburgh   Radio  Supply  House Pittsburgh.    Pa.  286 

WJAZ  Chicago    Radio    Laboratory Chicago.    HI.     268 

WJBC  Hummer  Furniture  Co; LaSaUe.  IU.  234 

WJBD  Ashland    Broadcasting   Committee Ashland.    Wise.  233 

WJD  Denison    University GraniteviUe.    Ohio     229 

WJJD  Supreme  Lodge,  Loyal  Order  of  Moose Mooseheart,  III.     303 

WJY  Radio  Corp.  of  Ama Now  York.  N.  Y.     453 

WJZ  Radio  Corp.  of  Ama New  York.  N.  Y.      453 

WKAA  H.   F.    Paar Cedar   Rapids.    Iowa  278 

WKAD  Chas.  Looff  (Crescent  Park) East  Providence,  R.  I.  240 

WKAP  Dutee    W.    Flint Cranston.    R.    I.  234 

WKAQ  Radio  Corp.  of  Porto  Rico San  Juan,  P.  R.  340 

WKAR  Michigan     Agriculture    College East    Lansing,     Mich.  285 

WKAV  Laconia    Radio    Club Laconia,    N.    H.     254 

WKBE  K.  &  B.  Electric  Co Webster.  Massachusetts  231 

WKBF  Dutee  Wilcox  FUnt Cransten,  Rhode  Island  286 

WKY  Wky   Radio  shop Okla.   City.    Okla.  275 

WLAG  Cutting  <t  Washington  Radio  Corp Minneapolis,  Minn.      417 

WLAL  First  Christian   Church Tulsa. Okla.      250 

WLAP  Wm.  V.  Jordan Louisville,  Ky.  286 

WLAQ  Arthur  E.  Shilling Kalamazoo.  Mich.  283 

WLAX  Putnam  Electric  Co Greencastre.Ind.  231 

WLB  University  of   Minnesota Minneapolis.    Minn.  278 

WLBL  Wisconsin   State   Dept.  of  Markets Stevenspoint.   Wis.  278 

WLS  Sears    Roehuck    &    Co Chieago.    IU.      344 

WLW  Cro-ley    Mfg.  Co Cincinnati,  Ohio  422 

WMAC  J.  Edw.  Page  (Olive  B.  Meredith Cazenovia,  N.  Y.  261 

WMAF  Round    Hills    Radio    Corp Dartmouth,    Mass.  360 

WMAK  Norton  Laboratories Lockport,  N.Y.  273 

WMAL  Trenton    Hardware   Co Trenton,    N.   J.  256 

WMAN  First    Baptist    Church Columbus.  Ohio  286 

WMAQ  Chicago     Daily     News i Chicago,  IU.  447 

WMAV  Alabama    Polytechnic    Institute Auburn,  Ala.  250 

WMAY  Kingshighway    Presbyterian    Church St.    Louis.    Mo.  280 

WMAZ  Mercer    University Macon,    Ga.  261 

WMBB  Trianon    Ball    Room Chicago,   111.  250 

WMBF  Miami    Beach.    Fla.  J84 

WMC  Commercial     Appeal Memphis.  Tenn.  503 

WMCA  Hotel  McAlpin  (Greeley  Scuare  Hotel  Co.) New  York  City  341 

WMH  Ainsworth-Gates    Radio    Co Cincinnati,  O.  321 

WMU  Doubledal-Hill   Elec.  Co Washington,   D.  C.  260 

WNAB  The  Shepard  Stores Boston,  Mass.  250 

WN  AC  Shepard  Stores Boston,  Mass.  284 

WNAD  University  of  Oklahoma Norman,    Okla.  258 

WNAL  Omaha    Central    High    School Omaha. Nebr.  255 

WNAP  Wittenberg  College Springfield.  Ohio  271 

WNAR  First   Christian   Church Butler,    Mo.  230 

WNAT  Lennig  Brothers  Co.  (Frederick  Lennig) Philadelphia.  Pa.  254 

WNAX  Dakota  Radio  Apparatus   Co Yankton.   8.   Dak.  248 

WNYC  Dept.  of  Plant  and  Structures New  York,  N.  Y.  526 

WOAC  Page  Organ  Co.: Lima.  Ohio  260 

WOAE  Midland  College Fremont.  Nebr.  280 

WOAF  Tyler    Commercial    College Tyler.    Texas  363 

WOAG  Apollo     Theater     (Belvidere     Amusement     Co.) Belvidere.IU.  274 

WOAI  Southern  Equipment  Co - San  Antonio.  Texas  392 

WOAN  Vaughn  Conservatory  of  Music  (James  D.  Vaughn) .  .      Lawrenceburg.  Tenn.  280 

WOAO  Lyradion    Mfg.    Co Mishawaka.     Ind.  369 

WOAR  Lundskow.  Henry  P. Kenosha.  Wis.  225 

WOAT  Boyd  M.  Hamp Wilmington. Del.  360 

WOAV  Pennsylvania    National    Guard,    2d   Battalion,    112th    Infantry Erie,    Pa.  242 

WOAW  Woodmen  of  the  World Omaha,   Nebraska  526 

WOAX  Franklyn  J.  Wolff Trenton,  N.J.  240 

WOC  Palmer    School    of    Chiropractic Davenport.    Iowa  484 

WOCL  Hotel    Jamestown,    Inc. Jamestown.    N.    Y.  273 

WODA  James  K.  O'Dea Paterson.  New  Jersey  203 

WOI  Iowa  State  CoUege Ames.  la.  207 

WOO  John    Wnnamaker Philadelphia.    Pa.  509 

WOR  L.  Bamberger  and  Co Newark,  N.  J.  405 

WORD  Peoples     Pulpit    Assn Bate  via,  HI.  273 

WOS  State    Marketing    Bureau Jefferson  City. Mo.  440 

WO WL  Owl  Batters-  Company New  Orleans.  La.  270 

WPAB  Pennsylvania     State     CoUege State  College.  Pa.  283 

WPAC  Donaldson    Radio    Co Okmulgee.  Okla.  360 

WPAJ  Doolittle  Radio  Corp New  Haven.   Conn.  268 

WPAK  North   Dakota  Agricultural  College Agricultural  CoUege.  N.   D.  283 

WPAL  Superior   Radio  &   Telephone  Equipment  Co Columbus.   Ohio  286 

WPAZ  John  R.  Koch  (Dr.) Charleston.  W.  Va.  273 

WPG  The  Municipality  of  Atlantic  City Atlantic  City.  N.  J.  300 

WQAA  Horace    A.    Beale,    Jr Parkersburg.    Pa.  270 

WQAC  E.  B.  Gish Amarillo, Texas  234 

WQAE  Moore  Radio  News  Station   (Edmund  B.  Moore) 6pringfield,  Vt.  273 

WQAM  Electrical     Equipment    Co Miami,  Fla.  283 

WQAN  Scranton     Times Scranton.     Pa.  280 

WQAO  Calvary  Baptist  Church New  York.  N.  Y.  360 

WQAS  Prince- Walter  Co LoweU.  Mass.  268 

WQJ  Calumet  Rainbo  Broadcasting  Co Chicago,  HI.  447 

WRAA  The  Rice  Institute Houston.  Tex.  256 

WRAF  The  Radio  Club  (Inc.) Laporte,  Ind.  224 

WRAK  Economy-  Light  Co Escanaba,  Mich  256 

WRAM  Lombard  CoUege Galesburg.  HI.  244 

WRAN  Black  Hawk  Electrical  Co Waterloo.  Iowa  236 

WRAQ  St.  Louis  Radio  Service  Co St.  Louis.  Mo.  263 

WRAV  Antioch   CoUege YeUow  Springs.   Ohio  242 

WR AW  Avenue  Radio  Shop   (Horace  D.  Good) Reading.  Pa.  238 

WRAX  Flaxon's    Garage Gloucester   City.    N.    J.  268 

WRBC  Imanuel  Lutheran  Church Valparaiso.  Ind.  278 

WRC  Radio  Corp.  of  Ama Washington,  D.  C.  468 

WREO  Reo  Motor  Car  Co Lansing.  Mich.  286 

WRHF  Washington  Radio  Hospital  Fund Washington,  D.  C.  256 

WRK  Doron    Bros Hamilton,    Ohio  360 

WRL  Union   College Schenectady.    N.   Y.  270 

WRM  University  of  Illinois Urbana,  HI.  273 

WRR  PoUce  and  Fire  Signal  Department Dallas    Tex  261 

WRW  Tarrytown  Radio  Res.  Labs Tarrytown    N    Y  273 

WSAB  Southeast  Missouri  State  Teachers  CoUege Cape  Girardeau   Mo.  275 

WSAC  Clemson  Agricultural  College Clemson  CoUege'  S.  C  336 

WSAD  J.  A.  Foster  Co Providence,  R.  I.  261 

WSAG  Loren  Vanderbeck  Davis St.  Petersburg    Fla  264 

WSAI  United  States  Playing  Cards  Co Cincinnati' Cbio  325 

WSAJ  Grove  City  College Grove  City,  Pa.  258 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


67 


The  Latest  in  Binocular  Coils 

{Continued  from  page.  65) 
right  angles  to  the  plane  of  the  coil  can- 
not generate  a  current,  as  opposing  cur- 
rents will  be  generated  on  the  near  and 
far  sides  of  the  conductors.  No  matter 
in  which  direction  a  stray  field  may  strike 
the  coil,  it  is  wholly  unable  to  induce  a 
troublesome  current. 

In  Fig.  8  are  shown  two  of  the  coils 
mounted  side  by  side  with  the  center-to- 
center  distance  (M).  By  experiment  it 
has  been  shown  that  the  faces  of  the  coil 
can  be  spaced  so  that  (L)  is  from  14"  to 
K"  without  trouble  from  feed-back. 

Here  (b)  represents  the  extreme  of 
field  as  before,  and  the  heavy  arrows 
show  the  course  of  the  magnetic  flux. 
In  the  center  is  the  disc  which  supports  the 
coil  and  the  connection  posts,  and  at  the 
bottom  is  the  floor  bracket  used  for  base 
mounting.  This  bracket  can  also  be 
used  for  mounting  the  coil  on  the  back 
of  a  variable  condenser,  when  such  con- 
struction is  desired.  The  connections 
are  plainly  marked  and  the  transformer 
can  be  hooked  up  in  any  circuit  just  as 
with  any  other  air  core  transformer  for 
straight  R.  F.  amplification,  reflexing  or 
as  a  tuning  coil.  A  .00035  condenser  is 
recommended  for  the  broadcasting  range 
of  wavelengths. 


The  Binocular  Coil 

By  P.  D.  Lowell,  Research  Engineer,   A.   H.  Grebe 
&  Co. 

IN  DESIGNING  and  constructing  a  radio 
frequency  amplifier  having  a  plurality  of 
tuned  stages,  it  is  extremely  important  that 
all  electro-magnetic  induction  between  the 
coils  of  the  tuned  stages  shall  be  eliminated; 
otherwise  a  feeding  back  of  energy  will  occur, 
thereby  causing  violent  oscillations  in  the 
whole  amplifier  circuit.  These  oscillations 
are  of  course  very  objectionable  and  an  ampli- 
fier is  entirely  useless  in  this  condition. 

It  has  been  customary  heretofore,  in  order 
to  reduce  the  magnetic  induction  between 
stages,  to  mount  the  inductance  coils  in  such  a 
position  that  their  axes  are  at  a  90°  angle  with 
respect  to  one  another.  This  method  is  fairly 
satisfactory,  provided  that  they  are  really 
positioned  at  exactly  the  90°  angle.  It  is  very 
clear,  however,  that  this  would  be  a  difficult 
practice  to  follow,  inasmuch  as  the  slightest 
variation  from  the  90°  angle  will  cause  insta- 
bility in  the  operation  of  the  receiving  appara- 


tus. The  same  line  of  reasoning  holds  true 
for  any  method  where  the  faces  of  the  coils  must 
be  at  a  certain  angle  with  respect  to  one  another 
in  order  that  electromagnetic  induction  shall 
be  reduced. 

Our  laboratory  has  produced  a  new  form  of 
inductance  unit  which  is  composed  of  two 
solenoidal  coils  mounted  closely  together  with 
their  axes  parallel  and  with  the  two  windings 
connected  in  such  a  manner  that  their  electro- 
magnetic fields  are  opposing  each  other. 

This  means  that  as  soon  as  one  coil  of  the 
unit  starts  to  radiate  a  magnetic  field,  the 
other  coil  of  the  unit  at  the  same  time  radiates 
a  magnetic  field  of  equal  intensity  but  of  oppo- 
site direction,  and  the  two  fields  immediately 
counter-balance  each  other  and  the  resulting 
field  becomes  zero. 

The  great  advantages  in  the  use  of  such 
inductance  units  in  the  tuned  stages  of  an 
amplifier  are  very  apparent.  The  untis  may 
be  mounted  at  quite  a  veriety  of  positions 
with  respect  to  one  another  and  their  posi- 
tioning does  not  need  to  be  as  accurate  as 
with  the  usual  form  of  inductance  coils. 

In  a  receiver  comprising  a  number  of  tuned 
stages,  maximum  overall  selectivity  is  obtained 
only  when  the  energy  from  the  aerial  must  pass 
through  each  tuned  stage  before  reaching  the 
detector.  Quite  frequently  it  is  found  that  a 
receiving  set  which  is  amply  selective  for 
moderately  distant  stations,  sets  up  no  tuning 
barrier  for  powerful  nearby  stations.  The 
fault  usually  lies  in  the  cylindrical  coils  which, 
because  of  their  external  field,  pick  up  the 
interfering  signal  directly  in  the  detector  and 
intermediate  stages.  The  filtering  effect  of 
the  tuned  stages  is  thus  greatly  reduced  and 
the  undesirablestationallowed  to  come  through. 
This  phenomenon  is  entirely  eliminated 
when  binocular  coils  are  used,  because 
the  inherent  selectivity  of  each  tuned  stage  is 
maintained  even  when  the  set  is  operated 
close  to  a  powerful  broadcasting  station. 

The  following  is  an  explanation  of  the  schem- 
atic diagram,  Fig.  9. 

"A"  and  "B"  are  two  similar  coils  connected 
in  series  or  parallel  in  ^uch  a  manner  that  their 
electromagnetic  field  are  opposing  each  other. 
When  a  source  of  electromagnetic  field  is 
radiated  from  an  exterior  source  such  as  coil 
"C,"  we  can  assume  that  E.  M.  F.  of  X  +  2 
units  value  is  induced  in  coil  "A"  and  an  E. 
M.  F.  of  — 2  units  is  induced  in  coil  "B". 
Therefore  "A"  and  "B"  being  connected  in 
the  proper  manner,  the  X+2  units  and  the  — 2 
units  will  counter-balance  one  another  and 
the  resulting  E.  M.  F.  across  the  terminals  of 
the  whole  inductance  will  be  xero. 


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68 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


WSAN       AUentown  Call  Publishing  Co Allentown,  Pa. 

WSAP        Seventh  Day  Adventist  Church New  York,  N.  Y. 

WSAR       Doughty  &  Welch  Electrical  Co Fall  River,  Mass. 

WSTA       Camp   Marienfeld Chesham,   N.   H. 

WSAV        C.  W.  Vick  Radio  Construction  Co Houston.  Tex. 

WSAY  Irving  Austin  (Port  Chaster  Chamber  of  Commerce) .  .  .  Port  Chester,  N.  Y. 

WSAZ        Chaa.  Electric  Shop Pomeroy,  Ohio 

WSB  Atlanta  Journal Atlanta,  Ga. 

WSK.C       "World's   Star  Knitting  Co Bay  City,   Mich. 

WSL         -J.  and  M.  Elec  Co Utica.  N.  Y. 

WSMB      Saenger  Amusement  Co.  and  Maison  Blanche  Co New  Orleans,  La. 

WSMH     Shattuck   Music  House Owosso,   Mich. 

WSOE       School  of  Engineering Milwaukee,  Wis. 

WSRF        Hardem  Sales  and  Service Broadlands.  111. 

WSUI         State  University  of  Iowa Iowa  City.  Iowa 

WTAB       Fall  River  Daily  Herald  Publishing  Co Fall  River,  Mass. 

WTAC       Penn  Traffic   Co Johnstown.   Pa. 

WTAF       Louis  J.  Gallo New  Orleans.  La. 

WTAL      Toledo  Radio  &  Electric  Co Toledo,  Ohio 

WTAP       Cambridge  Radio  &  Electric  Co Cambridge,  111. 


229 

WTAQ 

263 

WTAR 

254 

WTAS 

229 

WTAT 

360 

WTAU 

233 

WTAW 

258 

WTAX 

428 

WTAY 

261 

WTAZ 

273 

WTHS 

319 

WTG 

240 

WTIC 

246 

WTX 

233 

WWAD 

498 

WWAE 

248 

WWI 

360 

WWJ 

242 

WWL 

252 

WWOA 

242 

S.  H.  Van  Gordon  <fc  Son Osseo,  Wis.  220 

Reliance    Electric    Co Norfolk,  Va.  280 

Charles   E.   Erb9tein Elgin,   IU.  303 

Edison  Electric  Illuminating  Co (portable)    Boston,   Mas*.  244 

Ruegg  Battery  &  Electric  Co Tecnmseh,  Nebr.  242 

Agricultural  &  Mechanical  College  of  Texas College  Station.  Tex.  280 

Williams    Hardware    Co Streator,  IU.  231 

Oak  Leaves  Broadcastng  Station Oak  Park,  111.  283 

Thomas  J.   McGuire Lambertville,   N.   J.  283 

Flint    Senior    High    School Flint,    Mich.  218 

Kansas  State  Agricultural  College Manhattan.   Kana.  273 

Travelers  Insurance  Co. Hartford,  Conn.  323 

H.  G.  Saal  Co Chicago.  IU.  268 

Wright  &  Wright  (Inc.) Philadelphia,  Pa.  360 

The  Alamo  Ball  Room Joliet.  IU.  242 

Ford  Motor  Co Dearborn.  Mich.  273 

Detroit    News     (Evening    News    Assn.) Detroit,     Mich.  352 

Loyola     University New    Orleans,     La.  260 

Michigan  CoUege  of  Mines Houghton.  Mich.  244 


Canadian  Stations 


CFAC         Calgary    Herald - Calgary.  Alberta 

CFCA        Star  Pub.  &  Prtg.  Co Toronto.  Ontario 

CFCF         Marconi  Wireless  Teleg.  Co.  Canada Montreal,  Quebec 

CFCH        Abitibi  Power  &  Paper  Co Iroquois  Falls.  Ont. 

CFCJ         La  Cie  de  L'Evenement Quebec.  Quebec 

FCKC        Radio   Supply   Co Edmonton,    Alberta 

CFCN         W.  W.  Grant  Radio  (Ltd.) Calgary.  Alberta 

CFCQ        Radio   Specialties    (Ltd.) Vancouver.    B.   C. 

CFCR        Laurentide   Air    Service Sudbury,    Ont. 

CFCT        Victoria    City   Temple Victoria,   B.   C. 

CFCU        The  Jack  Elliott  Radio  Limited Hamilton.  Ont. 

CFCW       The  Radio  Shop .'...London,    Ont. 

CFDC        Sparks    Co Nanaimo,  B.  C. 

CFHC        Henry  Birks   &  Sons ^ Calgary,  Alta. 

CFLC         Chas.    Guy   Hunter 651  Adelaide  St.,   London.   Ont. 

CFQC        The  Electric   Shop   (Ltd.) '. Saskatoon.   Saskatchewan 

CFRC        Queens     University Kingston,  Ontario 

CFUC        University    of    Montreal Montreal,    Quebec 

CFXC        Westminster   Trust   Co New   Westminster.    B.   C. 

CFYC        Victor    Wentworth    Odium Vancouver.    B.    C. 

CHAC        Radio    Encineers Halifax.    Nova    Scotia 

CHBC       Albertan  Publishing  Co Calgary,  Alberta 

CHCB        Marconi    Company Toronto.  Ont. 

CHCD        Canadian   Wireless  A  Elcc.  Co Quebec.  Quebec 

CHCE       Western  Canada  Radio  Sup.  (Ltd.) Victoria,  B.  C. 

CHCL        Vancouver  Merchants  Exchange Vancouver,  B.  C. 

CHCM       Riley  &  McCormack Calgary.  Alberta 

CHCS        The   Hamilton   Spectator Hamilton,   Ont. 

CHIC         Northern    Electric    Co Toronto.    Ont. 

CHNC       Toronto     Radio     Researoh Toronto.  Ont. 


430 

CHXC 

400 

CHYC 

440 

CJBC 

400 

CJCA 

410 

CJGC 

410 

CJCD 

440 

CJCE 

450 

CJCF 

410 

CJCI 

410 

CJCK 

410 

CJCM 

420 

CJCN 

430 

CJSC 

440 

CKAC 

410 

CKCD 

400 

CKCE 

450 

CKCK 

400 

CKCO 

440 

CKCX 

400 

CKLC 

400 

CKOC 

410 

CNRA 

410 

CNRC 

410 

CNRE 

400 

CNRM 

440 

CNRO 

415 

CNRR 

420 

CNRS 

356 

CNRT 

350 

CNRW 

J.    R.    Booth Ottawa,  Ont.  435 

Northern  Electric  Co Montreal,   Quebeo  41 0 

Jarvis    Baptist   Church Toronto,   Ont.  31 2 

Edmonton  Journal Edmonton.  Alberta  455 

London  Free  Press  Prtg.  Co London,  Ont.  430 

T.    Eaton    Co Toronto,    Ont.  410 

Snrott-Shaw    Radio    Co Vancouver,    B.    C.  420 

The    News    Record Kitchener.    Ont.  295 

Maritime  Radio  Corp St.  John.   New  Brunswick  400 

Radio  Corp.  of  Calgary Calgary.  Alta.  316 

J.  L.  PhiUipe Mont  Joli,  Quebeo  430 

Simons  Agnew  &  Co Toronto,  Ont.  410 

Evening    Telegram Toronto.  Ont.  430 

La  Presse  Pub.  Co Montreal.  Quebeo  430 

Vancouver  Daily  Province Vancouver,    B.  C.  410 

Canadian  Independ.  Telephone  Co Toronto.  Ont.  450 

Leader    Pub.    Co Regina,    Saskatchewan  420 

Ottawa    Radio   Association t_  ttawa,    Ont.  440 

P.  Burns  &  Co Calgary.  Alberta  440 

Wilkinson   Electric   Company Calgary.   Alberta  400 

Wentworth    Radio    Supply    Co Hamilton,    Ont.  410 

Canadian  National  Railways Moncton,  N.  B.  313 

Canadian  National  Railways Calgary,  Canada  357 

Canadian  National  Railways Edmonton,  Alta.  455 

Canadian  National  Railways Montreal,  P.  Q.  410 

Canadian  National  Railways Ottawa,  Ont.  430 

Canadian  National  Railways Regina,  Sash.  312 

Canadian  National  Railways Saskatoon,  Sash.  329 

Canadian  National  Railways Toronto,  Ont.  357 

Canadian  National  Railways Winnipeg,  Man.  384 


Cuban  Stations 


PWX  Cuban  Telsphon    Co Habana  400  2K 

2DW  Pedro  Zayas Habana  300  2HS 

2AB  Alberto  8.  de  Bustamanto Habana  240  20L 

20K  Mario  Garcia  Velez Habana  360  2WW 

2BY  Frederick  W.  Borton Habana  260  5EV 

2CX  Frederick  W.  Borton Habana  320  6KW 

2EV  Westinchouse  Elec.  Co Habana  220  6KJ 

2TW  Roberto  E.  Ramires Habana  230  6CX 

2HC  Heraldo  de  Cuba, Habana  275  6DW 

2LC  Luis  Casas Habana  250  6BY 

2KD  E.  Sanchez  de  Fuentes Habana  350  6AZ 

2MN  Fausto  Simon Habana  270  8BY 

2MG  Manuel  G.  Salae Habana  280  8FU 

2JD  Raul  Pare.  Falcon Habana  150  8DW 


Alvara  Daia Habana  200 

Julio  Power Habana  180 

Oscar  Cotlado Habana  290 

Amadeo  Saenz Habana  210 

Leopoldo  E.  Figueroa Colon  360 

Frank  H.  Jones Tuinuou  340 

Frank  H.  Hones Tuinucu  275 

Antonio  T.  Figueroa Cienfiegos  170 

Eduardo  Terry Cienfiegos  225 

Jose  Ganduxe Cienfiegos  300 

Valentin  Ullivarri Cienfiegos  200 

Alberto  Ravelo Steo.  de  Cuba  250 

Andres  Vinnet Stgo.  de  Cuba  225 

Pedro  C.  Anduz Stgo.  de  Cuba  275 


European  Broadcasting  Stations 

British  Stations 


2LO  London 3G5  5NO 

51T  Birmingham 475  5SC 

5WA  Cardiff 350  2BD 

6BM  Bournemouth 385  6SL 

2ZYJ  Manchester 375 


Newcastle 400 

Glasgow 420 

Aberdeen 492 

Sheffield  (relay  station) 303 


French  Stations 


Deforest 
License 


t   HONEYCOMB  COILS 

The  Universal  all-wave 
inductance.  Back  and 
front  panel  mountings. 
Send  25  c  for  Super 
Het.,  R.  F.  and  Honey- 
comb Coil  Circuits  and 
Complete  Catalog. 
Cbax.  A.  Bnnslen.  Un, 
615  Main  SU.Butialo,  N.  Y. 


5000 

RADIO  DEALERS 

buy  from 

HUD50N-R0SS 

123  W.  Madison  St.  Chicago 

.  Send  for  .dealers  discount. 


Mailing  Lists 

Will  help  you  increase  sales 
I  Send  for  FREE  catalog,  eiving  counts 
end  prices  on  thousands  of  classified 
names  of  yoo  r  best  prospective  custcm- 
ere— National ,  State  an cVLocal— Indivld- 
nals.  Professions,   Business  Concerns. 


99%<2%&tt5* 


eact] 


iouluCo.il|St.Louis 


In  the 

July  Radio  Age 

Brainard  Foote,  Frank 
D.  Pearne,  Roscoe  Bun- 
dy,  H.  Frank  Hopkins, 
John  B.  Rathbun,  and 
others  will  give  you 

Radio  Circuit  Forecasts 
for  the  Fall  of  1925! 

A  real  insight  into  the 
future  of  Radio — theo- 
retical and  technical ' 

Out  June  1 5 


RAULF 


RADIO  CONSOLE 

MFG.C0.562VEDDERST. 


# 


CHICAGO.    WRITE    FOR    CIRCULAR 


*     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  June,  1925 


WITH 


The  Magazine  of  the  Hour  69 


URERS 


"Brandes'    New    Adjustable    Table- 
Talker 

The  new  Adjustable  Table-Talker  re- 
cently announced  by  C.  Brandes,  Inc., 
makers  of  the  Matched  Tone  Headsets 
and  pioneers  of  the  §10  loud  speaker 
market,  is  another  step  forward  in  the 
loud  speaker  development.  It  has  always 
been  Brandes'  idea,  says  their  sales 
manager,  to  give  to  the  radio  purchaser 
the  "greatest  buy  in  radio"  and  the  new 
Brandes  Table-Talker  is  today  the  best 
value  on  the  market  for  the  price. 

It  is  another  pioneering  step  in  that  it 
offers  not  only  an  adjustment  feature, 
but  a  gooseneck  fibre  horn  which  gives 
much  better  reproduction  than  the 
ordinary  straight  neck  horn. 

The  adjustment  lever  is  located  at  the 
back  of  the  base  in  an  inconspicuous 
place  and  yet  in  a  very  convenient 
position.  This  adjustment  greatly  in- 
creases the  volume  of  sound  produced 
and  sensitivity  of  the  Table-Talker  and 
makes  tuning-in  distant  stations  much 
easier.  All  adjustments  can  be  made  as 
shown  above  without  lifting  the  Table- 
Talker  from  the  table. 

The  horn  over  all  is  18  inches  high 
having  a  10  inch  bell.  It  is  finished  in  a 
neutral  shade  of  dark  brown  and  has  a  felt 
padded  base.  It  requires  no  extra  bat- 
teries for  operation  and  is  furnished  with 
a  five  foot  polarity-indicating  cord. 


Hudson-Ross    History    Reads   Like 
a  Fable 

How  the  smallness  of  Cinderella's  slip- 
per made  her  a  princess  was  once  looked 
upon  as  a  mere  fable.  But  Gloria  Swan- 
son's  trim  ankle  lifted  her  out  of. a  stove 
heated  flat  to  the'  titled  position  of  a 
marchioness. 

Only  three  years  ago  Hudson-Ross  was 
nothing  more  than  an  idea.  But  the  idea 
was  like  Cinderella'  slipper  or  Gloria's 
ankle.  It  was  what  has  made  this  com- 
pany leap  into  leadership  almost  over- 
night. 

Modest  quarters  were  secured  in  the 
Madison  Square  Building  on  Madison 
Street.  The  unusual  service  Hudson- 
Ross  gave  their  dealers  in  handling  only 
nationally  advertised  radio,  increased 
their  business  until  every  available  foot 
of  their  space  in  the  building  was  taken 
up. 

Now  comes  the  coach  and  four  of  the 
Princess  that  called  for  Cinderella. 
Business  has  reached  such  proportions 
that  more  commodious  quarters  were 
rented  at  116-118  So.  Wells  St.,  Chicago. 

May  1st,  of  course,  was  the  great  date. 
From  that  day  on  Hudson-Ross  occupied 
the  finest  offices  of  any  radio  house  in 
the  west. 

But  mere  physical  property  is  not 
enough  to  keep  pace  with  the  demands 
of  their  dealers.  Service  is  the  company's 
outstanding  feature. 


A  Pencil  Looks  Tall  Beside 
Amplion  Dragonfly- 
People  who  room,  live  in  kitchenette 
apartments,  thin-walled  flat  buildings  or 
other  places  where  a  "Loud"  Loud 
speaker  might  invite  the  wrath  of  neigh- 
bors, must  have  been  in  mind  when  this 
Amplion  "Dragonfly"  was  created. 

Although  it 
measures  only 
"knee  high"  to  the 
usual  loud  speaker 
(being  but  nine  in- 
ches tall),  it  is  in 
no  sense  a  toy. 
Without  being  for- 
ced it  fills  a  room 
with  reception  of 
surprising  clarity 
and  natural  tone. 
In  fact,  one  is  in- 
clined to  disbelieve 
gj  his  ears  on  first 
H^H  hearing  it  repro- 
duce. 
The  explanation  of  The  Amplion  Cor- 
poration of  America,  280  Madison  Ave., 
New  York  City,  is  that  this  "Dragonfly" 
is  a  replica  on  a  reduced  scale  of  a  larger 
Amplion,  with  all  its  features. 

A  rubber  bushing  insulates  the  horn 
from  the  tone  conduit.  Another  rubber 
bushing  insulates  the  tone  conduit  from 
the  unit.  The  curve  of  the  tone  conduit 
provides  long  tone  travel,  with  gradual 
amplification,  in  compact  space. 

The  unit  itself  is  the  same  as  is  supplied 
to  set  makers  for  built-in  loud  speakers. 
It  has  the  Amplion  "Floating  Dia- 
phragm" feature  and  an  adjustment  for 
"tuning"  it  to  each  set. 


The  Adapto  Radio 
Cabinet 

A  beautiful  console  now  on  the  market, 
encloses  everything  radio  from  sight  in  an 
uncommonly  safe  and  accessible  way. 
Because  it  accommodates  practically 
any  sized  receiver  with  absolutely  no  fuss 
or  cabinet  work,  through  the  use  of 
special  adapter  frames,  it  is  called  the 
Adapto  Radio  Cabinet.  This  console 
represents  a  significant  step  forward  in 
radio  consoles.  It  comes  in  either 
mahogany  or  walnut,  soft-toned  wood, 
harmonious  with  the  finest  receiver  and 
the  most  distinctive  room.  The  radio 
receiver  may  be  removed  instantly  with- 
out removing  a  single  nail  or  screw. 
There  is  a  drawer  that  represents  the 
utmost  in  convenience — it  opens  easily, 
smoothly,  and  holds  storage  battery, 
battery  charger,  distilled  water,  hydro- 
meter. A  built-in  switch  throws  the 
battery  charger  in  operation  instanty 
while  in  place.  The  horn  is  in  built  at 
the  top.  There  is  a  small  drawer  for 
tools,  a  spacious  shelf  for  B  batteries. 
Further  information  about  the  Adapto 
Radio  Cabinet  may  be  had  by  writing 
L.  R.  Donehue  Co.,  Perth  Amboy,  N.  J. 


The  Hemco  Loop  Aerial 

The  Hemco  Loop  Aerial,  manufactured 
by  George  Richards  &  Company,  Inc., 
557  West  Monroe  Street,  Chicago,  was 
designed  to  meet  the  demand  for  a 
reasonable  priced  and  durable  loop  aerial 
that    would   insure   efficient   reception. 

The  manufacturers  of  the  Hemco 
Loop  Aerial  feel  that  this  has  been 
accomplished  as  the  Hemco  Loop  Aerial 
possesses  a  number  of  advantages  over 
many  of  the  Loops  on  the  market  today. 
Made  in  sizes  of  18"  and  24"  it  is  con- 
structed of  a  65  strand  wire,  5  strands 
of  which  are  phosphorus  bronze  spirally 
wound  on  specially  treated  arms  which 
are  protected  at  both  ends  by  ferrules. 
These  wooden  arms  are  nicely  finished 
and  trimmed  with  nickel. 

The  binding  posts  on  the  Hemco  Loop 
Aerial  are  carried  on  a  hard  rubber  base, 
and  the  three  tap  feature  permits  the 
use  of  this  Aerial  on  circuits  where  Rice 
methods  of  regeneration  is  used. 

Probably  the  most  important  feature 
of  the  Hemco  Loop  Aerial  is  the  fact 
that  the  patented  spring  arm  feature 
keeps  the  wire  taut  at  all  times.  Con- 
cealed springs  hold  the  wires  under  ten- 
sion from  the  moment  the  Loop  is  opened. 


Dongan  Voltmeters  to 
Be  Standard 

An  announcement  has  just  been  made 
by  the  radio  Division  of  the  Dongan 
Electric  Manufacturing  Company, 
Detroit,  of  interest  both  to  the  trade  and 
the  set  manufacturers.  In  line  with  the 
tendency  on  the  part  to  set  manufac- 
turers to  build  more  complete  receiving 
sets,  Dongan  has  brought  out  a  line  of 
voltmeters  that  many  of  the  manu- 
facturers have  already  adopted  as  stand- 
ard equipment. 

The  commercial  set  builders  realize 
that  the  apparently  inefficient  operation 
of  the  set  is  often  due  to  improper  tube 
or  "B"  battery  voltage.  Frequently 
the  owner  of  the  set  does  not  realize  this, 
and  blames  the  unsatisfactory  results 
upon  the  set  itself.  In  fact,  several  of 
the  large  set  builders  have  found  that 
much  of  the  service  work  required 
is  due  to  improper  tube  or  B  battery 
voltage. 

Many  of  the  sets  now  being  designed 
for  next  season  include  Dongan  Volt- 
meters mounted  on  the  panels.  Obvious- 
ly this  addition  as  standard  equipment 
is  going  to  serve  the  double  purpose  of 
protecting  the  good  will  of  the  manu- 
facturer and  improving  the  consistent 
reception  of  the  set  to  the  pleasure  of  the 
owner. 

Dongan  is  best  known  in  radio  as  the 
manufacturer  of  Dongan  Audio  Trans- 
formers, a  product  this  company  builds 
for  thirty-five  set  manufacturers  as  well 
as  the  jobbing  trade.  (Turn   to  page  72) 


70 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


CLASSIFIED  ADVERTISEMENTS 

Don't  overlook  the  value  of  RADIO  AGE'S  classified  advertisements.  Many  such  messages 
have  paved  the  way  to  independent  incomes. 

The  classified  advertising  rates  are  but  ten  cents  per  word  for  a  single  insertion.  Liberal 
discounts  are  allowed  on  three,  six  and  twelve-time  insertions,  of  five,  fifteen  and  thirty  per  cent 
respectively.  Unless  placed  through  an  accredited  advertising  agency,  cash  should  accompany 
all  orders.  Name  and  address  must  be  included  at  foregoing  rates  and  no  advertisement  of  less 
than  ten  words  will  be  accepted. 

All  classified  ads  for  the  July  issue  must  be  sent  in  by  June  1. 


AGENTS  WANTED 


iles  on  ono  gallon  of  Gas.  It  has  b 
lileage  can  be  made.  AIRLOCK  gu 
iase  gas  mileage;  also  prevents  radia 
mer  or  freezing  in  winter.  Cools.  Fu 
the     Ford     motor.        Splendid     territ 

open.     AIRLOCK  PRODUCTS,  Box  703G,  Willow  Str. 

Long  Beach,  Calif. 


boiling  in  I 


RADIO— Join  our  sales  organization  and  make  big 
money.  We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers. Widener  of  Kansas  City  makes  $150.00 
weekly.  You  can  do  as  well  or  better.  Write  today 
for  catalog,  and  discounts.  Name  your  county.  Wave- 
land  Radio  Company,  Div.  52,  1027  No.  State  St.,  Chi- 
cago.   III. 

MANUFACTURER'S  AGENT  calling  on  Radio-Elec- 
trical  Jobbers,  Chicago  and  vicinity,  has  opening  for  3 
additional  lines  carrying  volume  business,  as  we  cater 
to  large  jobbers.  Edelstein,  1804  McCormick  Bid., 
Chicago. 

AGENTS— WRITE  FOR  FREE  SAMPLES.  Sell  Madison 
"Better-Made"  Shirts  for  large  manufacturer  direct  to 
wearer.  No  capital  or  experience  required.  Many 
earn  $100  weekly  ond  bonus.  MADISON  MFGRS.,  501 
Broadway,  New  York. 

90c  an  hour  to  advertise  and  distribute  samples  to  con- 
sumer. Write  quick  for  territory  and  particulars. 
American  Products  Co.,  2130  American  Building,  Cin- 
cinnati, Ohio. 

Man    wanted     for    this    territory    to    sell    wonderful 
value    men's,    women's,    Children's    shoes    direct,    sav- 

Samples  supplied.  Big  weekly  permanent  income. 
Write  today  Tanners  Mfg.  Co.,  1334C.  St.,  Boston,  Maes. 


RADIO  DEALERS 


DEALERS — Write  for  our  illustrated  catalog  of  reliable 
Radio  Merchandise.  Rossiter-Manning  Corporation, 
Dept.  D.  1830  Wilson  Ave.,  Chicago,  III. 


STAMPS  AND  COINS 


Venezuela,  Salvador  and  India  Service.  Guatemala, 
China,  etc.,  only  5c.  Finest  approval  sheets.  50  to 
60  per  cent.  Agents  Wanted.  Big  72-p.  Lists  Free. 
We  Buy  Stamps.  Established  20  Years.  Hussman 
Stamp  Co.,  Dept.  152,  St.  Louis,  Mo. 


WANTED 


WANTED — To  complete  my  set  RADIO  ACE  need 
August,  September.  October,  November,  1923,  issues, 
bound  or  unbound.  Advise  price.  Lloyd  C.  Henning. 
Hellbrook.  Arizona. 


INVENTIONS 


NEW  IDEAS  WANTED— Well  known  Radio  Manufac- 
turer whose  products  are  nationally  advertised  and  sold 
everywhere  wants  new  Radio  device  to  sell.  Will  pay 
outright  or  royalty  for  idea  or  invention  which  is  really 
new  and  saleable.  Address:  Mr.  R.  F.  Devine,  Room 
1101,  116  West  32nd  St.,  New  York,  N.   Y. 


Make  $100  Weekly -5eA'  RADIO 

Demonstrate  Once  —  Results  Mean  Sure  Sale 

Coast  to  coast, lowest  prices,attrac- 
tive  four-tube  instrument  $39.50. 
,  Big  commission  to  you.  Exclusive 
Steiritory  to  proven  salesmen.  Ter- 
yritory  going  fast,  write  today  for 
flarge  illustrated  book  No.  100. 
(Don't  fail  to  name  your  countv. 
OZARKA,  Inc. 

629  Washington  Blvd.  Chicago,  III. 


HELP  WANTED 


RADIO  SALESMEN  and  SET  BUILDERS — We  need 
you  and  you  need  us.  If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  111. 


MANUFACTURING  FACILITIES 


AN  OLD  AND  WELL  ESTABLISHED  MANUFACTUR- 
ING COMPANY  IN  THE  MIDDLE  WEST  WITH  LARGE 
WELL  EQUIPPED  PLANTS  AND  UNUSUAL  FINAN- 
CIAL RESOURCES,  DESIRING  TO  ENTER  THE  RADIO 
FIELD  WILL  CONSIDER  THE  MANUFACTURE  AND 
SALE  OF  RADIO  SETS  OR  DEVICES  OF  OUTSTAND- 
ING AND  UNUSUAL  MERIT  ON  A  ROYALTY  BASIS. 
ADDRESS  BOX  1A,   RADIO  AGE. 


RADIO 


A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  111. 


Standard  soderless  radio  Jacks.  Binding  post  attach- 
ments. Double  circuit.  One  dollar  bill.  Postpaid. 
Clinton  Seward,  Jr.,  New  Paltz.   New   York,   N.   Y. 

Three  Cosmopolitan  Phusiformers.  each  $5.50,  book  of 
instructions   included.      F.   A.    Mall,   Triopli,    Iowa. 

FOR  SALE— 3  Pfanstiehl  tuning  units.  3  Cardwell  Con- 
densers, 1  Bradleyomoter,  2  Bradleystats.  All  goods 
New.     Earl  Price,  Lodi,  Wis. 

15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.  Every  item  guaranteed.  Tell  us  your  needs. 
IMPERIAL  RADIO  COMPANY,  Delaware,  Ohio. 


RADIO  SETS.      Our  prices  save  you  money.      Lists  free. 
The  Radio  Shoppe,  Box  645,  East  Liverpool,  Ohio. 

JOIN  THE   RADIO  Parts  Exchange  Club.      Your   parts 

inspected    (Fee  25c),   and   exchanged   for   the   parts   you 

need.      What    have    you;    what    parts    do    you    require? 

Write  us  for  details. 

The  Radio  Parts  Exchange  Club,   112  So.  Homan  Ave., 

Chicago. 


"B"    BATTERIES 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parts  and  plans — complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake,  Chicago. 

BATTERIES  FOR  SALE— Four  24-volt  "Main"  Storage 
"B"  Batteries,  never  used,  shipped  and  ready  to  wire 
for  $38.00.  First  order  gets  the  batteries.  Address 
Box  B,   Radio  Age,   500  N.    Dearborn   St.,  Chicago,   111. 


BUSINESS   OPPORTUNITY 


MANUFACTURER: 

nil  111 


uld  you  be  interested  in 
advertising  campaign  to  reach  more  than 
t  prospective  buyers  of  quality  radio  products 
ch  week?  Do  you  want  to  establish  agencies  in 
territory  and  create  national  interest  in  your 
uct — at  a  very  conservative  cost?  It  can  be  done, 
us  explain  our  system  without  obligation  to  you. 
.  a  card  to  Radiograph  Laboratories,  1234  Rosemont 
,  Chicago,  III.,  Box  6. 


Hfie^mffic  Cop       * 

Trap  to  your  Radio  Set  %o 
and  "  Police' '  your  recep- 
tion.      Regulate  traffic.  ,«m.,m 
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Widely    imitated    but 
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cessful   WAVE    TRAP. 
Now  in   its  third   year. 
Sent  Postpaid  upon  re- 
ceipt of  $8.50  or  CO.  D. 
plospostage.  Send  for  Free  Booklet 

FERBEND  ELECTRIC  CO. 
16E.  So.  Water  St.  •         Chicago 

#     Tested  and  Approved  hy  RADIO   AGE 


WRITERS 


NEW  WRITERS  WANTED— Articles,  stories,  poems, 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No.  bunk.)  NOT  A  CORRE- 
SPONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
azines. Send  self  addressed  envelope  for  list  of  100 
subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Los 
Angeles,  Calif. 

WRITERS— Cash  in  on  your  knowledge  of  radio  by 
writing  for  Radio  Magazines  and  Newspaper  Supple- 
ments. Write  up  your  radio  experiences,  your  new 
hook-up,  your  knowledge  of  broadcasting  stations  and 
artists.  Experienced  authors  will  correct  and  improve 
your  manuscripts— make  them  typically  professional 
work.  FREE  Criticism  and  Advisory  Service  until  your 
manuscript  is  sold!  ALL  Magazines  and  Papers  de- 
manding fiction  and  articles  dealing  with  radio.  Here 
is  \OUR  OPPORTUNITY  to  profit!  Send  for  FREE 
booklet,  "How  You  Can  Sell  Your  Manuscripts." 
Willis  Arnold  and  Associates,  210  East  Ohio  St. 
Chicago,  111. 


Make  big 

W.    C.    Krug,    A 


ey  ' 


iting  Movie  Plays.     Circulars  free. 


RADIO  CIRCUITS 

SPECIAL  FOR  MAY 
The  Reinarti  Radio  Booklet,  by  Frank  D.  Pearne,  fully 
illustrated,  and  RADIO  ACE,  for  $2.50.      Price  of  Book- 
let alone  is  50c.      Send  check,  currency  or  money  order 
to  RADIO  ACE.  500  N.  Dearborn  Street,  Chicago. 


VOCATIONS 


Make    Big    Money.      Safe   and    Lock    Expert.      Ways 
Strong,  3800  Lan  Franco  St.,  Los  Angeles,  Calif. 


RADIO  SUPPLIES 


:>t    dii 


en   per   cent   discount   on   all   standard   radio   parts, 

for  our  latest  price  list,  with  special  bargains  on  Static- 
eliminators,  portable  loud  speakers,  Radiotrons,  Ger- 
man silver  wire,  etc.  RADIOCRAPH  LABORATORIES. 
1234  Rosemont  Ave.,  Dept.  4,  Chicago,  III. 


PATENTS 


FOR  SALE:  U.  S.  and  Canadian  Patent  on  an  Attach- 
ment for  Phonographs;  is  the  most  beautiful  inven- 
tion of  the  age.     Address  Chas.  F.  Smith,  Huff,  N.  Dak. 


CRYSTALS 


PERSONAL 


LONELY  HEARTS:  Exchange  letters;  make  interesting 
new  friends  in  our  jolly  club.  Eva  Moore,  Box  908, 
Jacksonville,  Florida.    Enclose  stamp. 

Lookl  You  Radio  Bugs!  Join  Radio  Correspondence 
Club.  Entirely  new.  Broaden  your  acquaintance, 
exchange  ideas.  Membership  open  to  LADY  BUGS 
also.  Dime  stamp  brings  pamphlet  and  Radio  Novelty 
Cards.     Radio  Rose,  Box  662,  Cleveland,  Ohio. 


PRINTING 


I,    Booklets,    Catalogs,    Circular; 
al  Press.  Batavia,  Ohio. 


MAGAZINES 


DREAMS.  A  magazine  for  all  who  dream.  If  you 
are  interested  in  the  subjects  of  science,  sex,  psychology, 
health,  love  and  romance,  you  cannot  afford  to  be  with- 
out this  magazine.  Three  dollars  will  bring  this  most 
fascinating  monthly  publication  to  your  home  for 
one  year.  M.  P.  Smith  Publishing  Co.,  508  N.  Dearborn 
St..  Chicago,  III. 


Classified  ad.  copy  fcr  the  July 
RADIO  AGE  must  be  sent  in  by 
June  1,  1925. 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


VI 


THE    RADIO    AGE 
BUYERS'    SERVICE 

What  do  you  want  to  purchase  in  the  radio  line?  Let  the  staff  of  RADIO  AGE  save  you 
time  and  money  by  sending  in  the  coupon  below.  Enter  the  number  of  the  article  you 
would  like  to  know  more  about  in  the  spaces  provided  in  the  coupon. 


1  "A"  Batterie, 

2  Aerial  protectors 

3  Aerial  insulators 

4  Aerials 

5  Aerials,  loop 

6  Amplifiers 

7  Amplifying  units 

8  Ammeters 

9  "B"  batteries 

10  Batteries   (state  voltage* 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Batter-,   substitutes 

17  Bezels 

IS  Binding  posts 

19  Binding  posts,  insulated 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wbeatstone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisers 

33  Coils 
choke 
coupling 


■  parts 


sers,  by-pass 
sers,  coupling 
sers,  filter 
sers,  fixed  (pape: 
phone) 


34  Coil 

35  Coil 

36  Coil 

37  Coil 

38  Coil 

39  Coil 

40  Coils,  Reinartz 

41  Coils,  stabilizer 

42  Coils,  tuning 

43  Cond 

44  Cond 

45  Cone 
ling 

46  Cone 

47  Cone 

48  Cone 

49  Cone 
grid, 

50  Condensers,  variabl. 

51  Condensers,  variabl, 

52  Condensers,  vernier 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  sets 

57  Couplers,  loose 

58  Couplers,  molded 

59  Couplers,  vario 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals, 

66  Crystals, 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crysta 

71  Dial,  adjusters 

72  Dials,  composition 

73  Dials,  hard  rubber 

74  Dials,  rheostat 

75  Dials,  metal 

76  Dials,  vernier 

77  Dials 

78  Dies 

79  Drills 


95  Grid  leak 

96  Grid,  trar 

97  Grid  leak, 

98  Grid  leak, 

99  Grinders. 

100  Ground  c 

101  Ground  r. 

102  Handles.  : 

103  Head  ban 

104  Head  pho 

105  Head  sets 

106  Honeycon 

107  Hook  ups 

108  Horns,  co 

109  Hon 

110  Hon 

111  Hon 

112  Hon 

113  Hyd 

114  Indi 

115  Indi 

116  Insu 

117  Insu 

118  Insu 

119  Insu 

120  Insu 

121  Insu 

122  Insu 

123  Insu 

124  Insu 

125  Insu 

126  Iron 

127  Jacks 

128  Filam 

129  Jars, 

130  Keys. 

131  Kn 


186  Rhe 

187  Rhe 

188  Rhe 

189  Rhe 


■stats,  automat 
istats,  battery 
stats,  dial 

its,  filament 


fibr, 


ete 


tors,  polarity 
tances.  C.  W. 
tion,  molded 


190  Rheostats,     poter 

191  Rheostats,  power 

192  Rheostats,  vernie 

193  Rods,  ground 

194  Rotors 

195  Scrapers,  wire 

196  Screwdrivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving — c 

200  Sets,  receiving — c 

201  Sets,     receiving- 
down 

202  Sets,     receiving  - 

203  Sets,  receiving — p 

204  Sets,   receiving — I 

205  Sets,     receiving — 

206  Si 


Ide 


fibre 

high  voltage 
cloth 
glass 

hard  rubber 
elain 


207  Sets 

208  Sets 

209  Sets 

210  Sets 


ing — regenei 

ng— section, 
tg — short  wi 
ing — super-: 

utting 


rited 


/ith  knobs 


nted 


132  Knock-down  panel  units 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arresters 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  units 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instruments 

142  Megohmeters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeters 

148  Minerals 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,       condenser 
leak 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,  honeycomb 

156  Mountings,     inductance 
switch 

157  Name  plates 

158  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeters 


electr; 


211  Sets, 

212  Slate 

213  Shellac 

214  Sliders 

215  Socket  adapte 

216  Sockets. 

217  Solder 

218  Soldering  iron 

219  Soldering  paste 

220  Solder  flux 

221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 

226  Stampings 

227  Stators 

228  Stop  points 

229  Switch  arms 

230  Switch  levers 

231  Switch  points 

232  Switch  stops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switches,  ground 

237  Switches,  inductance 

238  Switches,  panel 

239  Switches,  single  and  do 
ble  throw 

240  Tone  wheels 

241  Tow 


sfo 


161    Os. 


drilled 


electric 
80,  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

83  Enamels,  battery 

84  Enamels,  metal 

85  End  stops 

86  Eyelets 

87  Experimental  work 

88  Fibre  sheet,  vulcanized 

89  Filter  reactors 

90  Fixtures 

91  Fuse  cut  outs 

92  Fuses,  tube 

93  Generators.high  freemen 

94  Grid  choppers,  rotary 


164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  soldering 

168  Patent  attorneys 

169  Phone  connectors,  m 
pie 

170  Phonograph  adapter! 

171  Plates,  condenser 

172  Plugs,  coil 

173  Plugs,  telephone 

174  Pointers,  dial  and  kn 

175  Poles,  aerial 

176  Potentiometers 

177  Punching  machines 

178  Reinartz  set  parts 

179  Regenerative  set  part 

180  Receiver  caps 

181  Rectifiers,  battery 

182  Resistance  leaks 

183  Resistance  units 

184  Rheostat  bases 

185  Rheostat  strips 


242  Tn 
quency 

243  Transfc 

244  Transfc 

245  Transfc 

246  Transfc 

247  Transfc 
quency 

248  Transfc 

249  Transn 

250  Tubes, 

251  Tubes, 

252  Tubes, 

253  Tuners 

254  Va 

255  Va 

256  Va 

257  Va 

258  Varic 

259  Varie 

260  Varnish,  insult 

261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 

265  Wire,  aerial 

266  Wire,  braided  a 

267  Wire,  copper 

268  Wire,  insulatec 

269  Wire,  Litz 

270  Wire,  magnet 

271  Wire,  platinun 

272  Wire,  tungsten 


pier 
pie, 


RADIO   AGE    BUYERS'  SERVICE,  500   N.   Dearborn   St.,   Chicago,   111. 

Please  see  that  I  am  supplied  with  buying  specifications  and  prices  on  the  articles  numbered  herewith: 


I  I 


1111 


I I  I 


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6-Volt.  13-Plate 14.25 

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ACCURATUNE 

MICROMETER        CONTROLS 


I  am  a —  Dealer  H   Jobber  _    MfgTs.'   Rep.  □    Manufacturer 

Firm      [If   identified  with  Radio   industry] - _ 9 

My    Occupation   ._ — _ . - - - „ 

My    Name    _ _ - — - 1 

i 


Address 
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*     Tested  and  Approved  by  RADIO  AGE     * 


SUPER-HETERODYNE 

Ultradyne— Haynes  GritEin— Rentier 
Dealers:   Send  for  Discounts.: 

HUD50N-R0K 

123  W.  Madison  St.  Chicago 


72 


RADIO  AGE  for  June,  1925 


The  Magazine  of  the  Hour 


With  the  Radio  Manufacturers 


Ultra-Lowloss  Condenser 
Here  is  a  departure  in  condenser  con- 
struction. Every  detail  in  the  construc- 
tion of  Ultra-Lowloss  Condensers  has 
been  designed  with  one  predominating 
thought  in  mind — highest  possible  effi- 
ciency by  overcoming  losses  usually  ex- 
perienced in  other  condensers. 

Special  design  and  cut  of  stator  plates 
produces  a  straight  line  wavelength  curve 
— separates  stations  evenly  over  the  dial. 


Minimum  of  metal  in  the  field  and  frame 
of  high  resistance  material  reduces  eddy 
current  losses.  Monoblock  mounting 
with  plates  cast  into  block  reduces  series 
resistance  and  insures  perfect  contact 
with  all  plates.  The  use  of  only  one  strip 
of  insulation  answers  the  function  of  two 
and  four  pieces  and  reduces  leakage 
losses  proportionately.  Adjustable  ball 
bearing  insures  smooth  rotation  and  con- 
stant  capacity   calibration. 

In  addition  to  low-loss  features,  the 
Ultra-Lowloss  Condenser  is  specially 
designed  to  simplify  close  accurate  tun- 
ing. With  two  stations  of  known  wave- 
lengths located  on  the  dial,  other  stations 
separated  by  the  same  number  of  meters 
are  the  same  number  of  degrees  apart 
on  the  dial.  The  dials  may  therefore  be 
accurately  calibrated. 


(Continued  from  page  69) 

New  Crosley  "Musicone" 
On  the  Market 

The  Crosley  Radio  Corporation  of 
Cincinnati,  Ohio,  have  placed  their  new 
loud  speaker,  the  "Musicone,"  on  the 
market  for  radio  fans,  thus  entering 
into  the  loud  speaker  field  in  addition 
to  the  manufacture  of  the  famous  Crosley 
line  of  radio  receivers. 

The  Crosley  Musicone  has  many  new 
and  unusual  features,  which  are  described 
in  the  illustration  and  explanatory 
table  on  this  page.  The  speaker  sells  at 
a  comparatively  low  price. 

A  new  unit  noted  for  its  clarity  and 
volume  has  been  incorporated  into  the 
Musicone,  which  is  now  being  distributed 
to  Crosley  dealers  throughout  the  coun- 
try 


Wade  Square  Law  Condenser 

The  Wade  Condenser  is  unusual  in  de- 
sign and  incorporates  many  features 
which  are  new  and  found  in  no  other 
condenser.  Both  sets  of  plates  are 
specially  insulated  from  frame.  A 
grounding  teiminal  is  provided  on  the 
frame;  thus  the  frame  becomes  a  shield 
and  the  condenser  may  be  used  in  the 
most  sensitive  circuits,  eliminating  body 
capacity    effects. 


Radio  Faking  on  the  Wane 

Radio  advertising  is  becoming  more 
accurate,  the  first  issue  of  the  new  publi- 
cation of  the  merchandising  section  of 
the  Better  Business  Bureau,  "Accuracy," 
says  in  an  article  headed  "Radio  Faking 
on  the  Wane."  With  this  good  news  for 
the  buyers  of  radio  equipment,  "Ac- 
curacy" also  refers  to  the  recent  steps 
taken  by  various  trade  groups  to  co- 
operate with  the  Better  Business  Bureau 
in  its  efforts  to  keep  radio  advertising 
free  from  misrepresentation,  and  says: 

"This  situation  is  not  merely  con- 
temporaneous with  the  launching  of  the 
merchandising  section  of  this  Bureau  and 
the  tangible  corrective  actions  taken  in 
numerous  specific  cases.  Constructive 
efforts  which  have  been  put  forth  from 
several  directions  are  bearing  fruit. 

"First,  the  industry  is  outgrowing  its 
infancy  and  leaders  are,  by  example, 
establishing  standards  of  selling  practice. 
Second,  for  months  past,  the  radio  trade 
press  has  devoted  much  space  to  edu- 
cational articles  and  to  strong  editorials 
urging  that  the  fair  name  of  the  industry 
be  protected.  Third,  local  newspapers, 
jealous  of  reader-confidence,  are  on  the 
alert  to  reject  deceptive  radio  advertising. 


Parts  in  the  Crosley  Musicone 

1.  Laminated     magnets  9.  Cone  diaphragm 

2.  Armature  10.  Set  screw 

3.  Armature  coils  11.  Magnet  frame 

4.  Armature  lever  12.  Base 

5.  Cord  13.  Rim 

6.  Pure  rubber  pads  14.  Frame 

7.  Lever  spring  15.  Metal  reinforcement 

8.  Lever  rod  .  16.  Felt  base 


"Who's  On  The  Air" 
Published 

Those  who  have  not  as  yet  made  the 
acquaintance  of  the  new  book  called, 
"Who's  on  the  Air,"  have  a  pleasant 
surprise  in   store  for  them. 

This  book  is  the  only  radio  book  of 
its  kind  and  contains  a  ready  reference 
to  who  is  on  the  air  between  the  hours 
of  8:50  a.  m.  and  3  p.  m.,  Eastern  Time. 
All  the  listener  has  to  do  is  look  at  his 
watch  and  open  the  book  and  he  can 
immediately  ascertain  who  is  on  the  air 
according  to  their  regular  broadcasting 
schedules. 

The  author  of  this  book  must  have 
been  an  enthusiastic  radio  fan,  because 
he  has  certainly  tried  to  give  his  brother 
fans  their  full  dollar's  worth.  The  center 
spread  is  a  distance  map.  There  are  six 
pages  of  broadcasting  stations  arranged 
by  call  letters  and  three  pages  arranged 
geographically,  a  page  showing  the  power 
of  the  -station,  four  pages  for  logging 
stations,  and  numerous  other  pages 
showing  symbols,   terms,   etc. 

"Who's  on  the  Air"  fills  a  real  need  in 
radio  reception  and  is  made  up  in  a  way 
that   makes  it  a  very  convenient  aid  to 


Angular  cutting  of  the  plates  gives 
perfect  straight  line  wavelength  curve, 
which  distributes  the  stations  evenly 
over  the  dial.  This  feature  not  only 
simplifies  tuning,  but  adapts  the  con- 
denser for  use  in  wave  meter  and  stand- 
ard circuits.  It  also  makes  it  possible  to 
locate  any  station  on  the  dial  after  once 
having  located  any  station  of  given  wave- 
length. 

Equipped  with  a  four  inch  vernier 
silver  finished  dial  graduated  in  three 
hundred  and  sixty  degrees.  Gear  ratio, 
sixteen  to  one,  which  is  equal  to  thirty- 
two  to  one  on  the  ordinary  one  hundred 
and  eighty  degree  dial.  This  three  hun- 
dred and  sixty  degree  dial  gives  greater 
distance     between      stations  for  tuning. 

Plates  are  stamped  brass,  soldered 
together  in  one  unit.  This  arrangement 
reduces  series  resistance  and  skin  effect 
losses. 

Wade  Condensers  are  manufactured 
by  the  Wade  Manufacturing  Company, 
Inc.,   1819  Broadway,  New  York. 


WENR  Now  on  the  Air 
Station  WENR,  owned  and  operated 
by  the  All-American  Radio  Corporation, 
at  2650  Coyne  Street,  Chicago,  Illinois, 
after  a  successful  initial  test  program, 
went  on  the  air  last  month  with  a 
regular  schedule. 

The  power  used  for  the  present  is  100 
watts,  with  a  wavelength  of  266  meters, 
and  will  divide  time  with  station  WBCN, 
also  of  Chicago  and  on  the  same  wave- 
length. The  present  schedule  of  WENR 
is:  Tuesday,  Thursday  and  Friday 
evenings  from  7  to  8  and  from  9  to  10: 
Saturday  6  to  8  p.  m.,  and  2:30  to  4 
p.  m.  Sundays. 

The  program  director  of  the  new  sta- 
tion   is    Frank    Westphal. 

the  broadcast  listener.  Although  the 
need  of  such  a  book  has  existed  for  some 
time,  the  tremendous  amount  of  patience 
and  monotonous  labor  has  probably  dis- 
couraged its  production  before. 

Further  information  can  be  obtained 
from  the  Air  "Guide  Publishers,  409 
National   Bldg.,   Cleveland.   Ohio. 


Is  The 

•  'ANNUAL' ' 

in  your 

Vacation 

Kit? 


TF  YOU  intend  to  take  a  trip  this 
Summer,  you're  surely  going  to 
keep  in  touch  with  Radio,  either  by 
bringing  a  set  along  or  building  one 
during  the  dull  afternoons,  from 
parts  you  can  take  with  you. 
AND  how  are  you  going  to  build  this 
set  or  study  up  on  radio  for  the  big 
season  that  is  bound  to  come  in  September? 

The  answer  is  simple.  All  you  have  to  do  is  to  invest 
ONE  DOLLAR  in  a  RADIO  AGE  ANNUAL  for  1925,  the 
world's  most  complete  and  authoritative  hookup  book, 
and  take  it  with  you,  whether  you  go  to  Eagle  River  or  the 
River  of  Doubt. 

Let  the  ANNUAL  for  1925  be  your  Radio  Companion  this 
Summer!  It  will  tell  you  whatever  you  want  to  know  in 
the  radio  line — from  troubleshooting  of  the  little  faults 
that  may  develop  far  from  home — to  the  actual  construction 
of  simple  portable  sets  or  elaborate  multi-tubers. 

GET  THE  ANNUAL  NOW— and  THEN  go  on  your  vacation! 
It  will  be  your  radio  safeguard!  . 


A  Wealth  of  Blueprints 
for  your  Dollar! 

How  many  blueprints  could  you  buy  for  a 
dollar  if  you  started  out  to  buy  them,  one 
by  one?  Very  few,  you'll  admit.  Yet  in  the 
RADIO  AGE  ANNUAL  for  1925  you'll  find 
sixteen  full  pages  of  blueprints  in  actual 
color,  explaining  concisely  every  important 
simple  and  complicated  hookup  developed 
during  the  past  year!  The  32-page  blueprint 
section  of  the  ANNUAL  is  worth  many 
times  the  purchase  price  of  the  book  alone. 
Order  the  ANNUAL  NOW— for  the  limited 
first  edition  is  rapidly  being  bought  up  by 
eager  radio  enthusiasts. 


$1.00  a 
Copy 


RADIO  AGE  ANNUAL 
FOR  1925 

Some  of  the  Features 


$1.00  a 
Copy 


How  to  read  and  understand  hookups. 
How  to  understand  radio  phenomena. 
Building  your  first  simple  set. 
How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set. 
How  to  amplify  any  kind  of  set. 
Making  a  reflex  set. 
Building  your  first  Reinartz  set. 
The  renowned  Baby  Heterodyne  No.  1. 
Adding  audio  and  radio  stages  to  the  Baby  Het. 
How  to  make  a  battery  charger. 
How  to  make  a  loud  speaker. 

RADIO    AGE    ANNUAL.    BLUEPRINT    SECTION    with    such 
popular  hookups  as  the  aperiodic  variometer,  loop  sets,  feed- 


back receivers,  neutrodynes,  retlex  hookups,  Baby  Het  No.  2,  a 
Wonder  Super-Het,  and  others. 

How  to  get  rid  of  interference. 

How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super-heterodyne  for  the  super  experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  ponular  Reinartz. 

AND  MANY  OTHER  UP-TO-THE-MINUTE  HOOKUPS  AND 
ARTICLES. 


RADIO  AGE  ANNUAL  COUPON 

RADIO  AGE,  INC., 

500  North  Dearborn  St.,  Chicago,  111. 

Gentlemen:       I  want  to  be  one  of  the  first  to  get  the  RADIO  AGE  ANNUAL  FOR  1925.       Enclosed  find  $1.00.       If 
I  am  not  satisfied  with  the  ANNUAL  I  will  return  it  within  five  days  and  you  will  refund  my  dollar. 

Name - - 

Address. — - - — - 

City - — State - 

6-25 


What  theTrirdijn  geU  where  its 

hotter  than  Jummer  / 


Crosley  Trirdyn — on  the  Sahara  Desert  at  mid-day 
— brings  in  Radio-Paris  on  the  loud-speaker! 

Not  only  at  mid-day,  but  in  February — in  Northern  Africa 
and  far  hotter  than  any  American  summer. 

The  picture  above,  a  post  card  snap  shot  sent  from  Tunis 
to  Mr.  Crosley,  by  D.  F.  Keith  of  Toronto,  Ont.,  tells  this 
story  on  the  other  side: — 

Tunis.  North  Africa,  March  3,  1925 
Dear  Mr.  Crosley : 

Fishing  here  is  rotten  but  radio  is  fine.  On  the 
Sahara,  using  three  tubes  on  the  Trirdyn  circuit,  recep- 
tion from  Paris  came  through  on  the  loud-speaker. 
Along  the  south  coast  of  the  Mediterranean,  using  this 
set,  six  or  eight  high  power  European  stations  came  in 
with  good  volume  by  day-light  and  all  of  them  after  dark. 
Can  usually  get  a  few  American  after  1  a.  m.  Can  you 
fish  with  us  this  year  ? 

Cordially, 

(Signed)  D.  F.  Keith 
Further  details  on  the  margins  of  the  picture: — 

Sahara  Desert,250miles  south  of  Algiers,February,  1925.  Receiving  noon- 
day concert  from  "Radio-Paris",  Paris,  using  aerial  and  counterpoise. 

Who  said  summer  in  America  is  a  poor  time  for 
radio — if  the  receiver  is  a  Crosley  Trirdyn? 
Every   radio    fan  —  actual    and    aspiring  —  is 
invited  to  think  this  over  and  then  act. 

On  the  Trirdyn  is  the  beautiful  new  Crosley  Musicone, 
radio  's  most  startling  development.  The  Musicone's 
abilities  and  its  beauty  are  so  superior  that  we  expect  it 
to  replace  half  a  million  loud-speakers  ihisyear.  $ 1 7.50, 

The  Crosley  Radio  Corporation,  663  Sassafras  St.,  Cincinnati 
Powel  Crosley,  Jr.,  President 

RADIO 

Better-^  Costs  Less 

*     Tested  and  Approved  by  RADIO  AGE     * 


Blueprint  Section  Every  Month 


^fo.Na 


of  the  Hour 


JULY 
1925 

25? 


MEHUUM 

1W-5 


S3&  Y 
6S    )! 


In  This  Issue — 

Ten  Commandments 
for  the  Listener 


A  New  Super-Heterodyne 

Solving  Tube  Troubles 

News  of  Radio  Age's 
Popularity  Contest 


MEET  YOUR  BROADCAST  FAVORITES 


SUPER-*11^* 
AUTODYNE 


*Tradc 
Mark 


New! 


A  Perfected  Super-Heterodyne 

Again  Silver-Marshall  Engineering  leads  the  field,  just  as  it  has 
since  the  first  Silver  Design  was  offered  less  than  a  year  ago. 

Not  content  with  a  seven-tube  super-heterodyne,  which  has 
become  the  acknowledged  standard  of  comparison  with  radio 
engineers  and  editors,  McMurdo  Silver,  Assoc,  I.  R.  E.,  has 
developed  "The  Super-Autodyne,"  a  six-tube  receiver  that  will 
outperform  average  seven  and  eight-tube  sets. 

Read  the  description  of  this  remarkable  radio  achievement  in  this  issue 
of  "Radio  Age."  Plans  and  instructions  describing  this  set  in  detail  may 
be  had  for  50c. 

Complete  Parts 


Each 
2  S-M  305A  S-L-W  Condensers- $  5.00 

2  4"  Moulded  Dials.. 1.00 

1  U.  S.  L.  6-Ohm  Rheostat 1.00 

1  U.  S.  L.  240  Ohm  Potentiometer 1.50 

3  Insulated  Top  Binding  Posts .05 

1  Carter  101  Jack .70 

1  Carter  102A  Jack 80 

1  S-M    211    Filter    with    Matched    Tuning 

Capacity 8.00 

2  S-M  Charted  Intermediate  Transformers     8.00 

1  S-M  101B  Coupling  Unit 2.50 

1  S-M  6-Gang  Socket  shelf  (536-201A,  537- 

UV199) _ 10.80 


2  Thordarson  3  1-2-1  Transformers 

2  .002  Condensers 

1  .0075  Condensers 

2  .000025  Balancing  Condensers 

1  S-M  .25  Meg.  Leak 

1  S-M  2  meg.  Leak _... 

1  Carter  No.  3  Jack  Switch 

1  Benjamin  8630  Switch.. , 

1  Belden  Color  cable ___ 

1  Pair  Benjamin  8629  Shelf  Brackets.. 

1  Bakelite    panel.    7"xl8"x3-16",    drilled, 

grained  and  engraved , 

Spaghetti,  bus  bar.  lugs,  screws,  buts,  etc. 


Each 

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.40 

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1.15 
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6.00 
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Send  for  "The  WHY  of  the  Super-Autodyne"— It's  Free; 
Dealers — Ask  for  Our  New  S-M  Catalog 


Silver-ffarsh&ll 


1 14  S.  Wabash  Avenue, 
Chicago,  Illinois 


¥     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Stations 
Don't  Bunch 
On  the  Dials 


* 


QLTRft-LOWLOSS 

CONDENSERS 


Showing  stations  "Bunch- 
ed" as  they  are  found  on 
a  100  degree  dial  using 
any  ordinary  condenser. 


The  location  of  the  same 
stations  on  the  same  dial 
using  Ultra-LowLoss^  Con- 
densers— "spread,"  c 
fying  tuning. 


4g& 


^^-^ 


«j*r 


11 


Ml 

IB 


.OOOSm/i  ^ 


-?ATENT  PENDING 


/ 


TlLTRTf-VSRHISR 

TUNING       CONTROL 

Simplifies  radio  tuning.  Pencil  record 
a  station  on  the  dial — thereafter,  sim- 
ply turn  the  finder  to  your  pencil 
mark  and  you  get  that  station  instant- 
ly. Easy — quick  to  mount.  Eliminates 
fumbling,  guessing.  A  single  vernier 
control,  gear  ratio  20  to  1.  Furnished 
clockwise  or  anti-clockwise  in  gold  or 
silver  finish. 


Silver  $2.50 


Tuning  Simplified  Now  j 


'  ■  'HE  day  of  tedious  fumbling  about  for  your  stations  is  past — science  has  been 
J-  brought  into  play.  Now,  -with  the  Ultra-LowLoss  Condenser  you  can 
instantly  tune  in  on  any  station  as  easy  as  turning  the  hands  of  a  clock  to  the  hour. 

With  one  station  of  known  wave  length  located  on  the  dial,  all  others  can  be 
found  instantly.  Each  degree  on  a  100  degree  dial  represents  approximately  3J-2 
meters  difference  in  wave  length.  This  applies  to  both  high  and  low  wave 
lengths.     Other  than  100  degree  dials  vary  accordingly. 

This  simplification  of  tuning  is  made  possible  by  the  new  Cutless  Stator  Plates 
to  be  found  only  in  the  Ultra-LowLoss  Condensers.  Every  feature  of  the 
Ultra-LowLoss  Condenser  was  developed  with  one  predominating  purpose — to 
overcome  losses  common  in  other  condensers.  Designed  by  R.  E.  Lacault, 
originator  of  the  famous  Ultradyne  Receivers  and  Ultra-Vernier  Tuning  Controls. 

At  your  dealer's,  otherwise  send  purchase  price  and  you  will  be  supplied  postpaid. 

Design  of  lowloss  coils  furnished  with  each  condenser  for  amateur  and  broadcast  wave 
lengths  showing   which  will  function  most  efficiently   with   the   condenser. 

To  Manufacturers  Who  Wish  To  Improve  Their  Sets 

Mr.  Lacault  will  gladly  consult  with  any  manufacturer  regarding  the  application  of  this 
condenser  to  his  circuit  for  obtaining  best  possible  efficiency. 

CONDENSER 

PHENIX  RADIO  CORPORATION,  ^Itt^J1' 


Gold  $3.50 


*     Tested  and  Approved  by  RADIO  AGE     ¥ 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITH   WHICH  IS  COMBINED  RADIO  TOPICS 


Volume  4 


July,  1925 


Number  7 


CONTENTS 

Cover  Design  by  A.  P.  Ehlum 

Page 
Radio  Editorials 4 

Four,  Five  or  Six  Tubes?. 7 

By  Roscoe  Bundy 
Learning  Tube  Characteristics 11 

By  H.  Frank  Hopkins 
How  Much  Coupling? 13 

By  Brainard  Foote 
The  Six-Tube  Super-Autodyne 1 5 

By  McMurdo  Silver 

Vacuum  Tubes  as  Distortion  Devices. 18 

By  Dr.  Peter  I.  Wold 

A  Word  on  the  Care  of  Batteries 19 

A  Simplified  Portable  Super-Het 21 

By  A.  J.  Haynes 

Tricks  of  Summer  Static —24 

"Gloria  Confesses":     A  Photograph ...25 

RADIO  AGE  "What  the  Broadcasters  Are  Doing" 

Studio-Land  Feature  Section 26 

RADIO  AGE  Institute  Monthly  Tests... ......34 

RADIO  AGE  Blueprint  Section.— .35 

By  John  B.  Rathbun 

Pickups  and  Hookups  by  Our  Readers.. ..43 

With  the  Radio  Manufacturers 69 


Radio  Age  is  published  monthly  by  RADIO  AGE,   Inc. 
Member:      Audit  Bureau  of  Circulations. 


Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500    N.  Dearborn   Street,    Chicago,    111. 
Publication   Office,    Mount    Morris,   111. 


Frederick  A.  Smith,  Editor 
Frank  D.  Pearne,  Technical  Editor 
M.  B.  Smith,  Business  Manager 


Advertising  Director 
HARRY  A.  ACKERBURG 

500  N.  Dearborn  St.,  Chicago,  III. 


Eastern  Representative 
DAVIDSON   &   HEVEY,    17  West  42nd  St.,  New  York  City 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 
preceding  date  of  issue 

Vol.  4,  No.  7.     Issued  monthly.     Subscription  price  $2.50  a  year.     July,  1925. 
Entered  as  second-class  matter  at  post  office  at  Mount  Morris,  Illinois,  under  the 
Act  of  March  3,  1879. 


■5.  by  RADIO  A  GE.  liv . 


A  Chat  With 
the  Editor 

YOU  can  count  on  the  fingers 
of  your  two  hands  the  basic 
radio  receiver  circuits  from 
which  all  the  many  scores  of 
hook-ups  now  existing  may  be 
developed.  All  those  basic  circuits 
are  to  appear  in  blueprint  form  in 
the  August  issue  of  this  magazine. 
Our  technical  staff  has  selected 
the  typical  circuits  which  represent 
the  various  bas;c  arrangements, 
most  of  which  have  appeared  dur- 
ing 1924  and  1925  in  RADIO  AGE. 
John  B.  Rathbun,  the  able 
draughtsman  whose  blueprints  in 
this  magazine  have  become  stand- 
ard in  schools  and  in  many  thou- 
sands of  radio  homes,  will  have 
in  this  de  luxe  edition  of  RADIO 
AGE  an  exhibit  of  tested  basic 
circuits  which  will  make  our  August 
issue  one  of  the  most  important 
radio  contributions  since  broad- 
casting began.  The  blueprint  sec- 
tion of  the  August  number  will 
itself  be  of  almost  the  bulk  of  the 
regular  magazine.  With  the  addi- 
tion of  other  standard  RADIO 
AGE  features  the  book  will  take 
on  proportions  that  should  delight 
the  fan  who  wants  his  radio  course 
from  crystal  to  super,  all  under 
one    cover. 

Notwithstanding  the  unusual 
value  offered  in  this  big  issue  of  our 
magazine  the  news-stand  price  will 
be  the  same  as  other  issues;  25 
cents.  It  is  a  matter  of  wide 
comment  that  RADIO  AGE  costs 
no  more  from  month  to  month 
than  other  standard  radio  publica- 
tions, although  its  blueprint 
section  in  each  issue  sets  it  apart 
from  all  other  magazines.  Now 
we  are  to  offer  you  a  complete 
collection  of  blue  prints  with 
complete  constructional  instruc- 
tion in  a  single  issue  and  for  the 
regular  price. 

We  would  advise  readers  who 
wish  to  make  sure  of  getting  this 
remarkable  August  number  that 
they  tell  their  newsdealer  to  reserve 
their  magazine  for  August  NOW. 
If  your  dealer  does  not  handle 
RADIO  AGE  write  to  us  at  500 
North  Dearborn  street,  Chicago, 
enclosing  25  cents  in  stamps  and 
we  will  mail  you  one  on  July  15, 
the  day  it  goes  on  sale. 

Editor  of  RADIO  AGE 


RADIO  AGE  for  July,  1925 


EVEREADY     HOUR 
EVERY   TUESDAY   AT  9  P.  M. 

(Eastern  Standard  Time) 
For  real  radio  enjoyment  tune  in  the  "Ever- 
eady  Group."    Broadcast  through  stations — 

WEAF  New  York         WEAR   Cleveland 

WJAR  Providence       WSAI     Cincinnati 

WEEI    Boston  WWJ      Detroit 

WFI 

WGR 

WCAE  Pi 


Philadelphia     wmr\f  Minneapolis 
Buffalo  wutAJlSt  Paul 

WOC      Davenport 


:;^:.  w= 


Get  a  good  set— 
and  Evereadys 

To  ENJOY  radio  for  die  rest  of  your  life,  get  the 
best  set  you  can  afford.  There  are  receivers  at  all 
prices,  made  by  reputable  manufacturers;  it  isn't 
necessary  for  anyone  to  get  'round-the-corner,  un- 
proved, unreliable  merchandise  at  any  price.  That 
applies  to  batteries  too.  Eveready  Radio  Batteries 
are  made  in  so  many  sizes  and  prices  that  there  is  a 
correct,  long-lasting  Eveready  for  every  receiver 
and  for  every  radio  home,  ship  or  commercial  sta- 
tion. Specify  Evereadys  for  your  new  radio  set.  It 
is  false  economy  to  buy  nondescript  batteries  at  any 
time.  In  the  long  run  you'll  find  it  most  economical 
to  buy  either  the  large  or  extra  large  Evereadys. 
Always  buy  Evereadys  and  enjoy  the  knowledge  that 
no  one  can  get  any  more  in  batteries  for  the  money 
than  you.  There  is  an  Eveready  dealer  nearby. 
Manufactured  and  guaranteed  by 

NATIONAL       CARBON      CO.,     Inc. 
New  York  San  Francisco 

Canadian  National  Carbon  Co.,  Limited.  Toronto,  Ontario 


Radio  Batteries 


*     Tested  and  Approved  by  RADIO  AGE     # 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


RADIO  CORPORATION  of  America  has  com- 
pleted its  "proof"  that  in  adopting  the  name 
RADIO  AGE  this  magazine  stepped  on  the 
cloven  hoof  of  the  corporation.  The  RCA  contends 
that  RADIO  AGE,  as  a  name,  infringes  on  the  name 
"Wireless  Age,"  a  publication  owned  by  the  Radio 
Corporation.  Radio  Corporation  last  fall  brought 
formal  action  in  the  United  States  Patent  Office  at 
Washington  opposing  the  application  to  have  RADIO 
AGE  registered  as  a  trade  mark. 

The  sS33,000,000  group  apparently  held  the  fond 
notion  that  RADIO  AGE  would  immediately  yield 
its  rights,  rather  than  go  into  a  legal  battle  with  one 
of  the  Four  Horsemen  of  Radio.  On  the  contrary, 
RADIO  AGE  engaged  the  services  of  several  of  the 
best  lawyers  obtainable  and  we  have  seen  the  thing 
through.  On  May  5,  in  the  Corporation  offices  in 
New  York,  the  Corporation  completed  the  taking 
of  testimony  of  its  own  witnesses.  The  Corporation 
labored  and  brought  forth  a  peanut  tube. 

It  was  an  imposing  array  of  witnesses  and  we  re- 
gretted that  Mr.  Sarnoff,  vice  president  and  general 
manager  of  the  RCA  horse,  was  unable  to  be  present. 
Mr.  Sarnoff  was  busy  preparing  for  a  banquet.  He  is 
a  banqueteer  of  parts.     No  hungry  Cassius  he. 

At  the  last  Hoover  conference,  Charles  E.  Erbstein 
faced  the  representatives  there  present  in  the  interest 
of  the  Radio  Corporation,  Westinghouse,  General 
Electric  and  American  Telephone  and  Telegraph, 
and  told  them  they  were  the  Four  Horsemen  of  Radio. 

The.  name  stuck.  A  few  weeks  later  Mr.  Sarnoff 
and  Mr.  Erbstein  were  present  at  a  radio  dinner  in 
New  York.  Mr.  Sarnoff  approached  Mr.  Erbstein 
and  asked  in  a  gently  sardonic  tone: 

"Tell  me;  which  one  of  the  Four  Horsemen  am  I?" 

"Pestilence!"    responded    Mr.    Erbstein   in   a    flash. 

"Not  famine?"  inquired  Mr.  Sarnoff,  somewhat 
taken  back. 

"You,  Famine?     Never!"  murmured  Mr.  Erbstein. 

So,  on  the  occasion  of  the  taking  of  depositions 
calculated  to  prove  that  RADIO  AGE  is  guilty  of 
unfair  competition  and  is  injuring  the  business  of 
"Wireless  Age,"  Mr.  Sarnoff  was  preparing  for  another 
banquet. 

It  was  necessary  that  the  RCA  witnesses  swear  to 
facts  that  would  support  the  contention  that  the 
words  "wireless"  and  "radio"  mean  the  same  thing. 
If  this  were  proved,  Radio  Corporation  might  hope 
to  get  somewhere  with  its  argument  that  in  adopting 
the  name,  RADIO  AGE,  this  magazine  was  appro- 
priating, in  effect,  the  name  "Wireless  Age."  which 
does  not  belong  to  this  magazine,  but  belongs  to  the 
New  York  monthly  wireless  publication,  every  share 
of  stock  in  which  is  owned  by  Radio  Corporation. 

The  witnesses  then  swore  "wireless"  and  "radio" 
meant  the  same  thing.  No  distinction  whatever  so 
far  as  the  man  on  the  street  was  concerned.  But  it 
developed,  on  cross  examination,  that  all  the  witnesses 
were  on  the  payroll  of  the  Corporation  and  therefore 
could  not  well  be  criticised  if  their  expert  views  on 
the  significance  of  words  partook  of  the  same  general 
tendency  as  the  views  of  the  kind  and  loving  old 
Radio   Corporation. 

It  also  was  necessary  to  prove  that  the  use  of  the 
name  RADIO  AGE  was  causing  injury  to  the  business 


of  Radio  Corporation's  magazine,  which,  they  assure 
us,  is  called  "Wireless  Age."  Therefore,  a  witness 
testified  that  newsdealers  get  the  two  magazines 
all  mixed  up  and  that  although  one  is  published  in 
New  York  and  the  other  in  Chicago,  dealers  often 
send  unsold  copies  of  RADIO  AGE  to  "Wireless 
Age."  The  circulation  manager  of  "Wireless  Age" 
produced  one  letter  in  support  of  this  contention. 
He  said  he  had  looked  hard  for  other  documentary 
evidence  of  the  universal  confusion  between  RADIO 
AGE  and  "Wireless  Age"  but  the  one  letter  was  the 
best  he  could  do. 

Another  Corporation  employe  swore  tnat  at  the 
Pageant  of  Progress  in  1922  he  heard  subscription 
solicitors  in  the  RADIO  AGE  booth  telling  the  gullible 
public  that  RADIO  AGE  was  published  by  the  Radio 
Corporation  of  America.  This  witness  testified  he 
immediately  complained  to  the  manager  of  the  Pageant 
that  the  RADIO  AGE  solicitors  were  telling  naughty 
little  lies.  So,  he  testified,  the  manager  threw  the 
solicitors  out  of  the  Pageant,  and  the  RADIO  AGE 
booth  remained  empty  and  free  of  guile  from  then  on 
until  the  show  closed.  This  witness  admitted  he 
never  brought  these  matters  to  the  attention  of  the 
officers  of  RADIO  AGE,  Inc.,  and  that  he  didn't 
report  the  incident  to  "Wireless  Age"  until  May,  1924 
— almost  two  years  later.  A  long  time  to  carry  such 
a  pineapple  around  in  one's  craw. 

Mr.  Pierre  Boucheron,  general  manager  of  the 
advertising  and  publicity  departments  of  Radio 
Corporation  and  vice  president  and  General  manager 
of  Wireless  Press,  Inc.,  which  publishes  "Wireless 
Age"  for  Radio  Corporation,  was  easily  the  star  wit- 
ness for  Radio  Corporation.  He,  too,  thought  "wire- 
less" and  "radio"  were  identical  in  meaning.  But  on 
cross  examination  he  admitted  that  since  the  action 
against  RADIO  AGE  was  begun,  the  name  of  the 
magazine  which  is  claiming  it  is  suffering  great  injury 
from  competition  by  RADIO  AGE  changed  its  own 
name  from  "The  Wireless  Age"  to  "Wireless  Age, 
The  Radio  Magazine."  The  change  was  officially 
announced  in  the  corporation's  magazine  last  No- 
vember. It  was  explained  in  this  announcement  that 
the  old  title  was  being  retained  in  part  so  that  the 
magazine  might  be  more  easily  identified  by  those 
who  were  more  specially  interested  in  wireless.  Yet 
"wireless"  and  "radio"  mean  the  same  thing! 

A  man  might  be  obviously  right  from  start  to 
finish  in  a  controversy  such  as  this  and  in  the  end 
might  prove  himself  to  be  right.  But  he  would,  have 
been  compelled  to  finance  his  defense  and,  though 
he  be  right  as  a  trivet,  he  could  not  obtain  recourse 
against  predatory  interests  who  put  him  to  all  the 
trouble  and  expense.  That's  why  a  $33,000,000 
band  of  patriots  has  a  big  advantage  in  opposing  an 
individual  of  much  more  modest  resources.  Doesn't 
seem  to  be  quite  all  square  with  our  fundamental 
ideals  of  equal  opportunity  and  equal  rights  under  the 
law,  does  it?  We  were  warned  three  years  ago  that 
if  RADIO  AGE  criticised  certain  radio  interests  those 
interests  would  step  on  us.  Yet  we  criticised  radio 
monopoly  and  we  are  going  to  keep  it  up.  If  we 
still  thrive  where  others  faint,  it  may  be  because  our 
readers  and  newsdealers  are  not  so  confused  as  some 
folks  hope  they  are. 


RADIO  AGE  for  July,  1925 

"Radio  Age 
Contest  Is 


Race  is 
Still  Neck 
and  Neck 
As  Aldine 
Starts  the 
Official 
Count  of 
Last-Minute 
Ballots; 
Name  of 
Winner  to 
Be  Revealed 
Next  Month 


BY  THE  time  this  issue  of  RADIO 
AGE  appears  on  the  news-stands, 
the  RADIO  AGE  Popularity  Con- 
test will  have  ended,  as  only  those  votes 
received  before  midnight  of  June  15 
will  be  credited  to  the  total  count  of 
candidates. 

As  this  review  is  being  written  (May 
16,)  there  still  remain  a  full  thirty  days, 
during  which  period  the  winner  will  be 
definitely  named,  and  judging  from  the 
heavy  voting  which  has  taken  place 
during  the  past  thirty  days,  no  candidate 
is  yet  assured  of  the  coveted  position 
at  the  head  of  the  list.  At  no  time  in  the 
history  of  the  contest  have  the  three 
leading  candidates  been  so  closely 
bunched. 

To  further  complicate  matters,  "Uncle 
John"  Daggett,  'way  out  on  the  Pacific 
Coast,  has  jumped  from  ninth  to  fourth 
place,  where  he  stands  menacingly, 
offering  dangerous  competition  to  the 
three  popular  leaders.  By  referring 
further  to  the  "Standing  to  May  15" 
it  will  be  found  that  Art  Linick  has  also 
bettered  his  position  by  stepping  one 
more  round  toward  the  top  of  the  ladder, 
from  eighth  to  seventh  place. 

On  this  page  will  be  found   an   illus- 


The  Magazine  of  the  Hour  5 

Popularity 
Now  Closed ! 


By  HARRY  ALDINE 


tration  of  the  shield  which  will  be  award- 
ed the  winner  of  the  RADIO  AGE 
Popularity  Contest.  From  a  background 
of  artistic  black  will  stand  out  in 
raised  gold  letters  The  Winner's  Name,  and 
the  inscription,  "First  Annual  RADIO 
AGE  Broadcast  Entertainers'  Popularity 
Contest— 1924-25." 

Surrounding  this  will  be  a  plain  gold 
border  conforming  to  the  shape  of  the 
shield.  The  gold  plate  will  in  turn  be 
mounted  on  a  dead  black  bevel-edged 
wooden  plaque,  to  which  is  attached  a 
chain  for  hanging.  The  size,  overall, 
is  six  by  eight  inches. 

While  several  ideas  were  offered  for 
the  design  of  the  shield,  the  one  accepted 
seemed  to  conform  most  to  the  principles 
of  dignified  simplicity,  and  was  therefore 
the  most  forceful  manner  of  declaring  to 
the  world  the  winner  of  the  contest. 

Following  is  the  standing  of  the  can- 
didates as  they  are  lined  up  at  present: 

WINNERS  OF  PRECEDING  MONTHS 

July ...Duncan  Sisters,  KYW 

August Bill  Hay,  KFKX 

September - .Karl  Bonawitz,  WIP 


At  the  left  is  the  at- 
tractive shield  which 
will  be  awarded  the 
winner  in  the  RADIO 
AGE  Popularity  Con- 
test, which  closed  on 
June  15.  Its  size  over- 
all is  six  by  eight  in- 
ches, and  a  detailed 
description  is  con- 
tained in  the  article  on 
this  page  by  Mr.  Ald- 
ine, the  persevering 
Contest  Editor  for 
this  magazine. 


October. : H.  W.  Arlin,  KDKA 

November — Bert  Davis,  WQJ 

December - Jack  Nelson  ,WJJD 

January Art  Linick,  KYW 

February Coon-Sanders  Orchestra,  KYW 

March John  S.  Daggett,  KHJ 

STANDING  TO  MAY  15 

Name  and  Classification  Where  Heard 

Karl  Bonawitz,  Organist WIP,  Philadelphia 

Bert  Davis,  Entertainer WQJ,  Chicago 

Bill  Hay,  Announcer KFKX,  Hastings 

John  S.  Daggett,  Announcer... KHJ,  Los  Angeles 

H.  W.  Arlin,  Announcer... ..KDKA,  Pittsburgh 

Coon-Sanders'  Nighthawks,  Orchestra,  KYW,  Chi. 

Jack  Nelson,  Announcer ...WJJD,  Mooseheart 

Art  Linick,  Entertainer. KYW,  Chicago 

Harry  M.  Snodgrass,  Entertainer 

WOS,  Jefferson  City 

Ford  &  Glenn,  Entertainers..... WLS,  Chicago 

Duncan  Sisters,  Entertainers. KWY,  Chicago 

Lee  Sims,  Pianist ...KWY,  Chicago 

Lambdin  Kay,  Announcer WSB,  Atlanta 

J.  Remington  Welsch,  Organist KWY,  Chicago 

Fred  Smith,  Announcer WLW,  Cincinnati 

E.  L.  Tyson,  Announcer. WWJ,  Detroit 

Hired  Hand,  Announcer WBAP,  Fort  Worth 

•'Sen"  Kaney,  Announcer .KWY,  Chicago 

Nick  B.  Karris,  Entertainer KFI,  Los  Angeles 

Jerry  Sullivan,  Announcer-Entertainer,  WQJ,  Chi. 

Edward  H.  Smith,  Director-Player 

WGY.  Schenectady 

Charles  E.  Erbstein,  Announcer WTAS,  Elgin 

Wendell  Hall,  Entertainer WDAF,  Kansas  City 

Howard  Milholland,  Announcer KGO,  Oakland 

Scottich  Rite,  Orchestra KGO,  Oakland 

Banks  Kennedy,  Entertainer WEBH,  Chicago11 

S.  Hastings,  Announcer KFI,  Los  Angeles 

Robert  Boniel,  Announcer WEBH,  Chicago 

Arion  Trio,  Instrumental KGO,  Oakland 

Gold  Dust  Twins,  Entertainers,  WEAF,  New  York 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Mr.  Manufacturer 

Would  you  write  100 
letters  to  100  people 
to  reach  just  two  men? 

Then,  before  you  invest  your  advertising  dollars — THINK! 


This  Association 
is  comprised  of 
the  leading  Ra- 
dio Magazines. 


An  analysis  shows  that  publications  of  general  circulation, 
newspapers  and  magazines,  devote  less  than  2%  of  their 
reading  columns  to  Radio — proving  that  in  the  opinion  of 
their  own  Editors  less  than  2%  of  their  readers  are  inter- 
ested in  Radio.  In  fact,  many  general  publications  carry  no 
Radio  editorial  matter.  Therefore — 98%  of  your  investment 
is  lost! 

On  the  contrary,  the  Radio  magazine  offers  100%  Radio 
editorial — attracts  100%  potential  buyers. 

Spend  your  advertising  appropriation  in  Radio  Magazines. 
Be  sure  of  the  greatest  possible  return  on  your  advertising 
dollar. 


Radio  Magazine  Publishers'  Association,  Inc. 

RADIO  AGE  is  a  member  of  the  Radio  Magazine  Publishers  Association,  Inc. 


JM  23  1925 


C1B661371 
RADIO  AGE  for  July,  1925 


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M.  B.  Smith 

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A   Monthly     Publication 

Devoted  to  Practical 

Radio 

Frederick  A.  Smith          p 

Editor 

■ "-II »■» »•» ' 

I ll-ll ii-ii 

ii-ii 

L 

What  will  Tomorrow  Bring — 

Four,  Five  or  Six  TUBES? 


Our  readers'  vote  is  requested  upon  the 
number  of  tubes  that  will  prove  most  popu- 
lar during  the  coming  radio  season.  Will 
economy  rule  with  the  use  of  the  four  tube 
set,  will  we  adhere  to  the  present  popular 
five  tube  set,  or  will  we  attain  quality  with 
the  six  tube  set  regardless  of  the  increased 
priced  This  is  a  question  that  the  radio 
dealers  and  RADIO  AGE  would  like  to 
have  answered  by  our  readers. 

IT  was  not  so  very  long  ago  that  the 
three  tube  regenerative  receiver 
marked  the  height  of  affluence  in 
the  radio  world  and  that  the  owner  of 
such  a  super-set  was  enviously  regarded 
by  his  fellow  B.  C.  L.'s  who  were  still 
getting  their  music  via  the  single  tube 
and  the  crystal  set.  In  those  days  we 
could  consistently  get  coast-to-coast 
reception  or  its  equivalent  on  three 
tubes,  and  with  the  tubes  retailing  at 
$6.50  each  and  the  receiver  itself  hover- 
ing around  the  §200  mark,  the  old  three 
lunger  was  held  in  the  same  regard  as 
the  most  elaborate  five  tube  set  of  the 
present  day.  It  tuned  as  broad  as  a 
barn,  howled  like  a  fiend  and  mushed  up 
the  signals,  but  in  her  day  the  old  three 
did  her  stuff,  as  the  many  DX  records  of 
1921-1922  will  testify.     ' 

Repeated  refinements  in  the  regenera- 
tive circuit,  brought  the  three  tube  re- 
generative up  to  a  high  degree  of  effici- 
ency in  bringing  in  distance,  but  in  the 
craze  for  distance  we  sacrificed  selec- 
tivity and  tonal  quality.  They  were 
superlatively  sensitive  to  weak  signals, 
but  as  most  of  the  old  timers  were  of 
the  single  circuit  type  or  were  provided 
with  the  old  inefficient  vario-coupler, 
they  were  very  broad-tuning  and  could 
not  possibly  cope  with  the  present  day 
congestion  of  radio  traffic,  even  though 
they  did  have  from  five  to  ten  tuning 
controls.  There  were  more  dials  and 
less  selectivity  in  1922  than  at  any 
other  time  in  radio  history. 

Just  as  a  review  on  the  subject  of 
tuning  controls  let  me  list  the  dials  and 
knobs  that  commonly  appeared  on  the 
panels  of  the  old  time  three  tube  three 
circuit  regenerative: 

1.  Primary  Variable  Condenser  Dial. 

2.  Rotor  of  Vario-Coupler  Dial. 

3.  "Tens"  Tap  Switch   Knob. 

4.  "Units"  Tap  Switch  Knob. 

5.  Series-Parallel  Switch  (Some- 
times). 

6.  Secondary  Variable  Condenser 
Dial. 


By  ROSCOE    BUNDY 

Trend  Seems  To  Be 
Toward  Clear  Music 


7.  Secondary  Tap  Switch  Knob. 

8.  Grid   variometer    Dial. 

9.  Plate  variometer   Dial. 

10.  Variable   Grid   Leak   Dial. 

11.  Detector    Rheostat    Knob. 

12.  First  Stage  Audio  Rheostat  Knob. 

13.  Second  Stage  Audio  Rheostat 
Knob. 

14.  Battery  Switch  Knob. 

The  Man  Pays  This  Time! 

SOME  price  to  pay  for  an  attempt  at 
selectivity!  A  maze  of  confusing 
controls  that  were  not  half  as  effective 
as  the  three  tuning  dials  and  two  rheo- 
stats that  appear  on  the  panel  of  the 
present  time  tuned  radio  frequency  re- 
ceiver, and  which  required  considerable 
practice  before  they  could  all  be  brought 
into  adjustment. 

The  constant  urge  for  more  distance 
resulted  in  the  first  appearance  of  radio 
frequency  steps  which  at  that  time  were 
simply  auxiliaries  to  the  original  regenera- 
tive receiver  and  increased  the  complica- 
tion  considerably   without   much   return 


DET  ADD  AUD 

F/6./.  /t'EGENE/?s4TlirE 


f/6.2  /r'£/ri-EX 


Figs.    1-2.         Three    Tube    Circuits    Com- 
monly    Used.        Dotted    Line    Represents 
Radio  Frequency  and  Solid  Line  is  Audio 
Frequency. 


in  the  way  of  improved  performance. 
The  radio  frequency  steps  were  coupled 
with  primitive  untuned  radio  frequency 
transformers  that  were  little  better  than 
coupling  condensers,  and  which  peaked 
badly  on  some  particular  wavelength, 
generally  on  the  wavelength  of  one  of 
the  local  stations  that  you  were  trying 
to  tune  out. 

At  this  stage  of  development  the  addi- 
tion of  tubes  was  a  serious  proposition, 
for  the  tubes  then  drew  anywhere  from 
0.75  to  1.0  ampere  each,  so  that  a  four 
tube  outfit  would  draw  up  to  four  am- 
peres total,  or  four  times  as  much  "A" 
battery  juice  as  the  largest  tubes  of  the 
present  day. 

You  could  easily  run  down  a  freshly 
charged  battery  in  the  course  of  one 
evening  and  then  wait  over  for  a  day 
while  you  recharged  your  battery  with 
some  ineffective  trickle  charger,  generally 
of  the  buzzer  type.  Those  were  the  days 
when  the  buzz  of  the  charger  was  con- 
tinuous in  the  land  and  when  the  battery 
spent  as  much  time  on  the  charger  as  on 
the  receiver.  You  would  feed  it  five 
amperes  all  day  only  to  have  the  receiver 
drain  out  all  of  the  profits  by  12  o'clock 
p.  m. 

There  is  no  doubt  but  what  the  0.25 
ampere  tube  of  the  201A  type  made  the 
multi-tube  set  a  practical  possibility, 
and  that  further  increases  in  the  number 
of  tubes  will  also  depend  upon  the  de- 
velopment of  tubes  of  the  199  type  which 
will  make  dry  cell  operation  practicable 
with  five  tubes  or  more. 

The  Reflex  Enters 

OWING  to  the  necessity  for  battery 
conservation  with  the  old  tubes,  the 
coming  of  the  reflex  circuit  was  heralded 
with  joy  and  much  of  1923  was  devoted 
to  the  development  of  the  reflex  circuit 
by  experimentally  inclined  amateurs. 
Partly  for  the  reason  that  the  radio 
frequency  transformers  of  1923  did  not 
measure  up  to  the  standards  demanded 
by  the  reflex,  and  partly  for  the  reason 
that  reflex  principles  were  not  well  under- 
stood, the  reflex  did  not  attain  .  the 
popularity  that  was  expected  by  its 
sponsors,  and  there  was  a  decided  ten- 
dency toward  falling  back  on  the  old 
reliable  regenerative  circuit,  with  which 
almost  any  beginner  could  expect  to  get 
some  sort  of  results.  There  were  many 
reflexes  that  gave  phenomenal  perform- 
ance, but  in  the  main,  the  radio  public 
soon  discovered  that  the  reflex  of  that 
time   was    not    an    ideal    circuit    for   the 


8 


RADIO  AGE  for  July,  1925 


wailings  that  were  prevalent  in  the 
regenerative  era  and  hear  music  and 
voice  without  a  background  of  hissing 
and  frying  sounds  that  formerly  de- 
tracted so  much  from  the  enjoyment  of  a 
program.  In  clarity  of  tone,  the  five 
tuber  was  nearly  equal  to  the  reflex  at 
its  best,  and  the  problem  of  perfect 
reception  was  therefore  put  up  squarely 
to  the  manufacturers  of  loud  speakers. 
It  was  now  a  question  of  developing  a 
horn  that  was  a  fit  running  mate  for  the 
receiver. 

New  Twists  Developed 

IN  the  meantime,   we  must  not  forget 
that  all  this  improvement  also  stimu- 
lated experimental  work  on  the  regenera- 


novice  and  that  special  precautions  were     accompaniment   of  the  shrieks  and  wild 
necessary  that  rather  took  it  out  of  the 
home-builder's   province. 

Things  hovered  around  this  condition 
for  some  time  until  a  change  in  radio 
took  place  with  the  appearance  of  the 
five  tube  neutrodyne,  the  father  of  all 
the  numerous  five  tube  "dynes"  now  on 
the  market  and  the  salvation  of  the 
reflex  principle.  The  neutrodyne  was 
not  the  first  tuned  radio  frequency 
outfit  by  any  means,  for  we  had  plate 
tuned  circuits  long  before  this,  but  it 
was  the  first  stable  five  tube  radio  fre- 
quency set  that  could  be  built  with  any 
degree  of  success  by  the  average  home- 
builder. 

With  all  due  respect  to  the  neutraliz- 
ing principle  as  applied  to  the  suppres- 
sion of  self-oscilla- 
tion in  the  radio  fre- 
quency stages,  the 
real  advantage  of 
the  neutrodyne,  ac- 
cording to  my  idea, 
lay  in  the  construc- 
tional details  such 
as  the  tuned  radio 
frequency  transfor- 
mer and  the  aper- 
iodic or  semi-aper- 
iodic coupler.  By 
these  units  we  could 
approach  a  degree 
of  selectivity  hither- 
to unknown,  by 
means  of  very 
simple  units;  and 
further,  we  could 
peak  our  radio  fre- 
quency amplifica- 
tion on  the  desired 
wavelength  instead 
of  adoptingthe  com- 
promise amplifica- 
tion of  the  older 
fixed  transformer. 
Again,  this  was  the 
first  fairly  high 
power  set  within 
reach  of  the  aver- 
age amateur  and  the 
first  practicable  set 
with  more  than 
three  tubes  which 
had  appeared. 
Tonal  quality  was 
improved  as  well  as 
distance  and  selec- 
tivity, and  in  gen- 
eral it  took  the 
radio  world  by 
storm  in  spite  of  the 
cost  of  the  five 
tubes,  which  aver- 
aged about  $5.00 
each  at  that  time. 

The  rapid  increase  in  the  popularity 
of  the  neutrodyne  brought  a  perfect 
flood  of  five-tube  tuned  frequency  sets 
on  the  market  with  all  sorts  of  weird 
methods  of  suppressing  free  oscillations. 
The  question  of  battery  current  consump- 
tion could  no  longer  be  leveled  against 
these  circuits,  for  the  201A  tube  gave  a 
total  consumption  of  only  1.25  amperes 
against  the  3.0  amperes  formerly  neces- 
sary with  the  old  tubes  in  the  three 
tube  regenerative  receivers;  hence  we 
could  run  longer  per  charge  with  the 
new  five  tube  combination  than  with  the 
old  detector-and-two-stage  outfit. 

Under  the  new  system,  coast-to-coast 
reception  on  the  loud  speaker  was  so 
common  as  to  cause  ho  comment  and 
we  could  bring  in  real  distance  through 
the  most  powerful,  local  broadcasting 
stations  with  ease.  For  the  first  time  we 
could    bring    in    a    station    without    the 


RADIO  AGE  BALLOT 

(How  Many  Tubes  Do  You  Prefer?) 

BALLOT  EDITOR, 

Radio  Age,  Inc., 
500  N.  Dearborn  St., 
Chicago,  111. 

On  the  following  list  I  have  checked  off  the  radio  receiver  that  best 
fills  my  requirements,  and  have  written  my  reasons  in  the  blank  space 
following  the  specifications. 

CLASS  1.  THREE  AND  FOUR  TUBES,  (a)  Three  Tube  regenera- 
tive with  transformer  coupled  audio  stages,  (b)  Four  Tube 
Regenerative  with  resistance  coupling,  (c)  Three  Tube 
Reflex,  (d)  Four  tube  reflex  with  loop,  (e)  Four  tube  regen- 
erative with  one  stage  of  radio  frequency. 
CLASS  2.  FIVE  AND  SIX  TUBES,  (a)  Five  Tubes,  two  stages  of 
radio,  detector,  and  two  stages  of  resistance  coupled  audio, 

(b)  Five  tubes,  One  stage  of  radio,  regenerative,  detector 
and  three  resistance  coupled  stages,  (c)  Five  Tube  Reflex 
with  loop,  (d)  Five  Tubes,  Two  stages  radio,  regenerative 
detector  and  two  stages  of  transformer  coupled  audio,  (e) 
Six  Tubes,  Two  stages  of  radio,  regenerative  detector,  and 
three  stages  of  resistance  coupled  audio,  (f)  Six  Tubes,  two 
radio,  detector,  three  stages  transformer  coupled  audio. 

CLASS  3.  SUPER-HETERODYNES,     (a)  Six  Tube,  (b)  Seven  tube 

(c)  Eight  tube. 

REASON  FOR  MY  CHOICE 

Name 

Street  or  R.  F.  D 

City State 

NOTE:  If  you  do  not  wish  to  tear  this  blank  out  of  your  book,  send  a  brief  note  covering 
the  above  points.    It  will  do  just  as  well. 


The  Magazine  of  the  Hour 

fixed  primary  coil.  In  fact,  a  modern 
three-tube  circuit  with  this  sort  of  tuner 
is  fully  the  equal  of  an  old  four  tube 
using  the  vario-coupler,  and  is  not  half 
as  bothersome.  Further,  it  can  be 
"logged"  so  that  each  station  comes  in  on 
a  definite  dial  position,  which  was  not 
formerly  the  case,  making  tuning  certain 
and  prompt  when  provided  with  a  table 
of  station  wavelengths  and  a  well  pre- 
pared "log"  of  the  corresponding  dial 
positions.  Logging  is  an  essential  with  a 
modern  receiver  of  any  type. 

Out  of  this  perfection  in  regeneratives 
sprang  a  hybrid  four-tube  circuit  type 
which  is  very  popular  today.  This  con- 
sists of  a  stage  of  tuned  radio  placed  in 
front  of  the  three  tube  regenerative 
which  both  increases  the  distance  and 
selectivity  and  also 
counteracts  the  ten- 
dency of  the  regen- 
erative unit  toward 
causing  annoying 
aerial  radiations. 
The  Browning- 
Drake  circuit  is  a 
prominent  example 
of  this  type,  which 
consists  of  one 
stage  of  tuned  radio 
frequency  amplifi- 
cation, regenerative 
detector,  and  two 
stages  of  audio  fre- 
quency amplifica- 
tion. Both  the 
coupler-tuner  and 
the  radio  frequency 
transformer  are 
special  adaptions  of 
the  tuned  coils 
originally  used  in 
the  neutrodyne, 
although  much  more 
efficient  and  selec- 
tive because  of  the 
absence  of  electro- 
static coupling  be- 
tween the  primary 
and  secondary  coils. 
Such  circuits  are 
rapidly  increasing 
in  favor,  for  they 
have  great  distance 
getting  qualities  for 
the  number  of  tubes 
employed  and  are 
simple  and  cheap  to 
build. 


tive  and  reflex  circuits  in  which  many  of 
the  radio  frequency  construction  details 
were  employed.  For  example,  the  aperiod- 
ic type  coupler  was  now  employed  on 
regenerative  and  reflex  circuits  as  well  as 
with  the  tuned  radio  frequency  outfits, 
at  one  time  improving  their  performance 
and  simplifying  the  controls.  The  old 
vario-coupler  became  a  thing  of  the  past. 
Single  control  regeneratives  became  more 
and  more  common,  both  wavelength 
and  regeneration  being  sometimes  con- 
trolled by  a  single  variable  condenser 
while  taps  and  tap  switches  were  placed 
in  the  discard. 

A  regenerative  circuit  of  the  new  era 
consisted  of  a  dial  for  tuning  to  wave- 
length, and  perhaps  another  dial  for 
the  tickler.  This  was  all  there  was  to 
the  proposition  and  we  not  only  simpli- 
fied things,  but  also  obtained  better 
selectivity,   tone   and   distance   with   the 


Revised  Reflex 
Circuits 

OU  R  reflex  cir- 
cuits now  took 
on  new  life  with  the 
advent  of  the  aper- 
iodic type  coupler  and  tuned  air  core 
radio  frequency  transformers,  with  the  re- 
sult that  the  modern  reflex  much  more 
nearly  approaches  its  theoretical  advan- 
tages. The  radio  frequency  component  is 
now  tuned  by  the  same  air  core  transfomer 
units  employed  in  the  tuned  radio  fre- 
quency sets  with  greatly  increased  range 
and  stability.  By  the  same  means,  ohmic 
resistance  is  reduced,  selectivity  increas- 
ed, and  wonderful  results  are  being 
obtained  with  only  a  few  tubes.  Two 
tube  reflex  sets  with  coast-to-coast  re- 
ception and  loud  speaker  volume  on  500 
mile  stations  are  not  uncommon  where 
the  improvements  have  been  added. 
Where  fixed  R.  F.  transformers  are  used 
we  now  have  true  magnetic  coupling  in- 
stead of  the  capacity  coupling  had  in  the 
older  types,  and  with  modern  untuned 
transformers  we  have  excellent  perform- 
ance. 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Three  tube  reflex  circuits,  using  tuned 
radio  frequency  transformers  through- 
out, give  fully  the  results  of  a  five  tube 
straight  radio  frequency  set  when  proper- 
ly built,  and  have  the  advantage  that 
they  can  be  operated  with  dry  cell  "A" 
batteries  with  success.  There  are  a 
number  of  "kit-sets"  or  complete  sets  of 
parts  now  on  the  market  for  building 
reflexes  of  this  type,  so  that  the  construc- 
tion of  a  reflex  no  longer  is  a  problem  for 
the  advanced  student  of  radio,  but  is 
entirely  practicable  for  the  rawest  novice. 
This  is  in  contrast  to  the  conditions  ex- 
perienced in  the  old  days  when  the 
builder  of  a  reflex  frequently  had  to  buy 
enough  material  for  two  sets  before  he 
could  find  parts  that  would  match  up 
and  function  properly  when  hooked  up 
in  a  reflex  circuit. 

In  writing  the  above  paragraph  it 
brings  to  mind  the  great  advantages 
enjoyed  by  the  present  day  radio  set 
builder  compared  with  the  trials  and 
tribulations  of  the  old-timer  who  had 
little  to  work  with  in  the  way  of  materials 
and  still  less  data.  In  the  old  times,  a 
smudgy  illustration  cut  out  of  a  news- 
paper with  an  exceeding  inaccurate  de- 
scription was  considered  a  "find,"  and 
with  a  few  yards  of  barb  wire  and  other 
miscellaneous  junk,  a  valiant  attempt 
was  made  toward  the  construction  of  a 
workable  receiver.  Nowadays,  the  build- 
er  can    obtain    accurate    apparatus    put 


RP  D6T  AUD  AUD 


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r/G.4./4/VPlJ./F:  /rfe^Z^X 


Figs.  3-4.  Four  Tube  circuits,  Regenerative, 

With  One  Radio  Stage  (3)  and  Reflex  Four 

Tube  (4) 

the  development  of  six  and  seven  tube 
super-hets  which  give  fully  as  good  per- 
formance as  the  standard  eight-tube 
type,  and  have  the  further  advantage 
that  they  are  more  compact,  cost  less,  and 
take  less  battery  current.  Satisfactory 
results  are  being  had  with  six  and  seven 
199  tubes,  which  brings  the  set  well  down 
toward  the  limits  of  dry  cell  operation, 
and  with  such  sets  we  obtain  wonderful 


up  in  complete  kits  so  that  an  hour's  work     selectivity    and    loud    speaker   operation 


with  a  screw  driver  and  pliers  is  all  that 
is  necessary.  Each  wire  is  cut  to  length 
and  a  detailed  series  of  picture  diagrams 
gives  all  the  data  that  anyone  could 
possibly  ask  for.  In  one  way,  however, 
all  this  spoon-feeding  is  a  bad  proposi- 
tion, for  it  is  getting  to  such  a  point  that 
the  experimenter  is  now  too  dependent 
upon  others  and  is  rapidly  losing  his 
spirit  of  self-reliance.  Here  at  RADIO 
AGE,  we  find  that  the  slightest  omission 
in  a  description  or  in  a  drawing  is 
sufficient  to  throw  him  all  out  of  joint, 
and  instead  of  trying  a  few  simple  experi- 
ments that  could  be  performed  in  five 
minutes,  he  will  write  in  and  calmly  wait 
for  some  one  to  work  out  his  simplest 
problems  for  him. 

The  Super- 
Heterodyne 

During  the  past 
year  much  work  has 
been  done  on  the 
development  of  the 
super- heterodyne 
principle  and  great 
progress  has  also 
been  made  along 
these  lines.  Properly 
designed,  and  with 
the  proper  mater- 
ials, the  super-het  is 
the  king  of  all  re- 
ceivers, but  once 
again  we  warn  the 
novice  that  he 
should  obtain  his 
apparatus  in  kit-set 
form  to  insure  all  of 
the  parts  being  prop- 
erly matched  so  that 
they  will  work  to- 
gether. To  assemble 
a  super-heterodyne 
out  of  a  miscellane- 
ous mass  of  un- 
matched parts  of 
different  makes  re- 
quires a  considerable 
amount  of  skill  and 
experience. 

Continued  experi- 
ment has  resulted  in 


over  great  distances.  Their  tone  value 
is  of  the  best,  and  with  a  little  experience 
they  are  easy  to  tune  and  handle.  In 
fact,  two  condenser  dials  and  a  potenti- 
ometer are  the  only  controls  necessary. 

Super-heterodynes  are  essentially  a 
type  designed  for  operation  on  a  loop 
aerial,  and  for  this  reason  they  make  a 
great  appeal  to  those  who  have  no  chance 
to  erect  an  effective  outdoor  aerial. 
Certain  radio  frequency  and  reflex  re- 
ceivers will  also  give  good  results  on  a 
loop,  but  the  super-het  is  particularly 
adapted  for  this  kind  of  service,  and  to  a 
great  extent,  its  selectivity  is  due  to  the 
directional  properties  of  the'  loop  aerial 
with  which  it  is  used.  Its  only  drawback 
is  its  cost,  which  is  considerably  greater 


4-— v.^4 — L^_^__i__ 


RF 


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Five  Tube  Circuits.     Two  Stages  of  Radio  Frequency  and  Audio  (5),  and 
Resistance  Coupled  Five  Tube  With  One  Radio  Stage  (6). 


than  that  of  a  corresponding  grade  of 
radio  frequency  or  reflex  receiver,  and 
this  item,  of  course,  is  sufficient  to  rule 
it  out  among  many  classes  of  radio  fans. 
When  the  DX  fever  was  at  its  height, 
with  every  effort  bent  toward  getting 
distance  at  any  cost,  very  little  atten- 
tion was  paid  toward  eliminating  dis- 
agreeable noises  or  for  improving  the 
tone  of  the  receiver.  In  fact,  the  noise 
in  the  early  broadcast  receivers,  coupled 
with  the  crude  loud  speakers  of  that 
period,  was  very  effective  in  holding 
back  prospective  customers  who  possess- 
ed the  most  elementary  sense  of  tone. 
The  field  was  entirely  in  the  hands  of  the 
distance  fanatics,  and  they  continued 
to  hold  it  until  the  coming  of  the  tuned 
radio  frequency  sets,  with  their  improved 
reception,  made  an  appeal  to  another 
class  of  listeners.  The  latter  formed  the 
bulk  of  those  who  purchased  radio  dur- 
ing the  past  year;  people  who  objected 
to  listening  to  the  mangled  remains  of  a 
sonata,  just  so  that  they  could  boast  of 
hearing  some  peanut  station  1,500  miles 
away.  Better  have  good,  clear,  local 
reception  on  a  crystal  set  for  these  pros- 
pects than  a  mushed  up  mess  coming  in 
from  a  distant  station. 

In  addition  to  the  inherent  noises  of 
the  regenerative  receiver,  which  were 
really  not  always  so  bad  on  the  head- 
phones, the  early  audio  transformers 
were  far  from  being  perfect  and  added 
their  din  to  the  collection  of  noises  an- 
nexed in  the  detector  stage.  High  ratio 
audio  transformers  with  their  distor- 
tion, poor  design  and  other  factors  made 
life  miserable  for  the  musician  who  was 
forced  to  hear  the  blasting  and  blare  of 
the  old  horns  or  noise  chutes.  Improved 
transformer  design,  together  with  the 
use  of  low  turn  ratios,  has  greatly  im- 
proved these  conditions  so  that  there 
is  little  distortion  or  noise  within  the 
receiver  itself.  Further,  the  introduction 
of  resistance  coupling  in  the  audio  stages 
made  another  step  toward  perfect  tone, 
so  that  the  tendency  of  today  is  rather 
in  the  direction  of  clear,  undistorted 
reception  than  toward  mere  distance. 

I  am  thoroughly  convinced  that  future 
improvements  in  radio  apparatus  will  be 
along  the  lines  of 
tonal  improvement 
and  that  the  buying 
public  is  more  inter- 
ested in  tone  quality 
than  in  the  attain- 
ment of  distance. 
A  good,  clear  nat- 
ural tone  with  mod- 
erate distance  get- 
ting qualities;  low 
current  consump- 
tion so  that  dry 
batteries  can  be  em- 
ployed; stable  per- 
formance without 
nerve  racking 
shrieks  and  howls, 
and  perfect  select- 
ivity are  the  char- 
acteristics of  the 
salable  radio  receiv- 
er of  the  future. 
The  experimenter 
and  the  DX  hound 
have  already  been 
served,  so  that  our 
next  appeal  is  to 
that  class  of  music 
lovers  who  have  not 
yet  seen  fit  to  buy 
radio  equipment. 

The  reproduction 
must  be  fully  equal 
to  that  of  the  best 
modern     phono- 


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RADIO  AGE  for  July,  1925 


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4T  &OT&  LO/V6  sWD  S/-/0/?T /?.E    W^}l/£/./EA/GT-/VS, 


Figs.  7-8.     Six  Tube  Circuits. 


Two  Stages  of  Radio   With  Resistance  Coupling  (7), 
Super-heterodyne  (8). 


graph,  and  this  should  not  be  so  difficult 
to  attain,  as  there  are  certain  mechanical- 
ly connected  linkages  in  the  phonograph 
which  do  not  exist  in  the  radio;  hence 
sound  without  distortion  should  be  more 
perfectly  accomplished  where  the  trans- 
mission is  performed  electrically  than 
where  loose  jointed  mechanisms  are  em- 
ployed. 

Resistance  Coupling 

PERFECT  as  the  modern  audio  fre- 
quency transformer  may  be,  there  is 
even  less  distortion  with  resistance  coup- 
ling, for  the  amplification  is  always  in 
exact  "straight-line"  proportion  to  the 
drop  of  potential  over  the  resistor  coupler. 
As  with  other  items  in  radio,  however, 
the  resistance  coupling  method  is  a  com- 
promise that  is  not  without  drawbacks 
of  its  own.  In  the  first  place,  we  must 
use  three  amplifying  tubes  with  the 
resistor  to  get  the  degree  of  amplifica- 
tion obtained  by  two  tubes  with  trans- 
former coupling;  and  in  the  second  place, 
we  must  use  at  least  135  volts  of  "B" 
battery  instead  of  the  conventional  90 
volts  used  with  the  transformers.  It  is 
the  same  here  as  everywhere  else.  If 
we  wish  to  gain  the  benefits  of  perfect 
reproduction,  we  must  pay  the  price  of 
admission,  and  according  to  my  ideas, 
the  better  quality  obtained  by  the 
resistors  fully  compensates  for  one  extra 
tube  and  one  extra  block  of  "B"  battery. 
The  application  of  the  resistors  is  simple 
and  reasonable  in  cost. 

In  what  is  to  follow,  add  one  tube  to 
the  set  for  resistance  coupling  where 
transformer  coupling  is  specified.  Some 
increase  in  amplification  with  little  or  no 
effect  on  the  quality  can  be  had  by  com- 
bining resistance  and  transformer  coupl- 
ing with  one  transformer  stage  and  two 
resistance  coupled  stages. 

How  Many  Tubes? 

At  last  we  are  getting  back  to  our 
original  question,  the  subject  of  this 
article,  after  wandering  around  among 
the  various  types  -  of  radio  receivers. 
What  is  your  preference,  or  rather,  what 
sort  of  a  radio  outfit  would  you  buy  if 
you  were  to  purchase  one  tomorrow? 
With  a  limited  amount  of  cash  available, 
would  you  prefer  a  three  tube  regenera- 


tive with  good  distance  getting  qualities 
but  only  fair  tone  value,  to  a  four  tube 
set  with  slightly  better  distance  and  tone 
providing  that  the  latter  only  cost  a  few 
dollars  more?  Would  you  prefer  these 
sets  to  a  three  or  four  tube  reflex  with 
wonderful  tone  value,  great  volume,  and 
moderate  distance?  I  am  omitting  refer- 
ence to  the  one  and  two  tube  sets  which 
are  really  for  the  head-set  and  can  only 
be  used  on  the  speaker  with  powerful 
local  stations. 

If  you  had  more  money  to  spend,  would 
you  spend  it  on  the  conventional  five 
tube  tuned  radio  frequency  set  with 
transformer  audio  stages,  or  would  you 
like  to  add  another  tube  for  resistance 
coupling  so  .that  you  would  have  the 
superlative  in  tone  value  for  the  R.  F. 
class  of  receiver?  How  would  a  five 
tube  reflex  operating  on  a  loop  strike  you? 

Now  for  the  third  class,  which  costs 
quite  a  little  more  than  any  of  the  others. 
We  speak  of  the  super-hetrodyne  with 
its  loop  aerial,  from  six  to  eight  tubes, 
and  with  its  excellent  tone  and  volume? 
Do  you  believe  that  these  increased 
virtues  compensate  for  the  additional 
cost  over  those  offered  by  the  five  and  six 
tube  sets  of  class  two?  That's  what  the 
manufacturer  wishes  to  know,  that  is 
what  we  wish  to  know,  and  that  is  what 
will  affect  the  market  in  which  you  are 
to  buy  your  radio.  There  is  only  one 
way  in  which  public  demand  can  be 
determined  and-  that  is  by  asking  the 
buying  public  to  vote  on  their  opinion 
or  desires  just  as  we  are  doing  here. 
We  have  guessed  until  we  are  blue  in  the 
face,  but  as  yet  have  come  to  no  con- 
clusion, and  there  are  a  whole  lot  more 
in  the  same  boat  with  us. 

In  making  your  choice,  please  consider 
the  many  factors  that  enter  into  the 
proposition.  The  question  of  tube 
economy,  compactness  and  portability, 
dry  cells  versus  the  storage  battery,  first 
cost,  distance,  tone,  volume,  selectivity, 
loop  aerial  or  outdoor  aerial,  and  the  cost 
of  maintenance.  There  is  some  one  com- 
bination of  these  factors  that  will  suit 
your  conditions  best  and  we  wish  to 
know  what  it  is.  We  have  divided  the 
receivers  into  three  classes  according  to 
price,  for  we  believe  that  price  is  the  de- 
termining factor  in  the  majority  of  cases. 


The  Magazine  of  the  Hour  , 

If  this  were  not  so,  then  everyone  would 
place  their  check  mark  opposite  one  of 
the  more  powerful  and  costly  sets  and 
we  would  be  as  much  in  the  dark  as  ever. 
Mark  your  ballot  candidly;  we  want 
to  know  just  what  is  on  the  minds  of 
our  readers.  Place  your  check  mark 
opposite  the  type  that  you  most  desire 
and  then  make  a  note  of  why  you  prefer 
this  particular  circuit.  This  is  as  much 
to  your  advantage  as  to  ours  and  is  not 
an  advertising  scheme — we  want  to 
know. 


The    Universal    Need 

LOUD-SPEAKER  operation  is  almost 
a  universal  requirement  with  the 
receiving  set  of  today;  hence,  we  must 
always  be  assured  of  the  equivalent 
of  at  least  two  transformer  coupled  audio 
frequency  stages.  So  far  as  marketable 
sets  go,  the  days  of  the  headset  are  prob- 
ably gone,  even,  on  distances  that  were 
considered  of  the  DX  order  several 
years  ago.  Even  with  portable  sets,  we 
see  provision  for  the  loud  speaker  and  in 
most  cases  the  loud  speaker  unit  is  built 
into  the  set  proper. 

Shorter  and  shorter  aerials,  or  aerials 
of  the  indoor  type,  increase  with  the 
increasing  numbers  of  broadcasting  sta- 
tions, for  a  short  aerial  is  almost  a 
necessary  adjunct  to  selectivity  in  these 
days.  Loop  aerials  are  very  popular  for 
much  the  same  reason,  and  also  because 
they  avoid  the  trouble  of  erecting  an 
outdoor    structure. 

There  is  probably  not  any  increased 
risk  due  to  thunderstorms;  in  fact,  the 
risk  may  possibly  be  less,  but  they  are 
not    desirable. 


Talks  on  Cuisine 
Station  KYW 

A  SERIES  of  eight  talks  closely  re- 
lated to  the  cuisine  in  your  home  is 
being  given  over  Westinghouse  station 
KYW,  each  Thursday  at  9:15  p.  m.  until 
June  25,  which  will  be  the  date  of  the 
last  talk. 

KYW  has  secured  the  co-operation  of 
John  C.  Cutting,  to  give  these  talks. 
Mr.  Cutting  has  been  telling  the  New 
York  women,  over  WJZ,  how  to  manage 
their  homes  and  husbands.  This  was 
a  weekly  feature  in  New  York  for  over 
sixteen  months,  and  his  thoughtful  and 
valuable  home  hints,  so  delightfully 
put  forth,  proved  to  be  of  such  value 
that  the  same  propaganda  is  going  to 
be  exploited  in  Chicago,  over  West- 
inghouse station  KYW. 

Mr.  Cutting,  who  is  secretary  of  the 
Meat  Council  of  Chicago,  began  his 
series  of  weekly  talks  from  KYW  on 
May  7,  at  9:15  p.  m.  having  chosen 
for  his  first  subject  "Filling  Four  Stom- 
achs With  a  Dollar  Bill."  Mr.  Cutting, 
who  enjoyed  the  prestige  of  being  the 
only  man  on  WJZ's  program  who  dis- 
cussed subjects  dear  to  a  woman's  heart, 
has  a  faculty  of  putting  these  talks  over 
with  the  enthusiasm  and  pep  required 
to  promote  his  idea.  He  will  tell  young 
wives  how  to  spank  up  a  roast  or  hem- 
stitch hamburger  in  a  way  that  will 
bring  them  the  eternal  love  of  their 
respective  husbands. 

Tune  in  and  let  him  do  his  stuff. 
KYW,   Thursdays  at  9:15   p.   m. 


RADIO  AGE  for  July,  1925 

^Formulae  and  Tables  for  Testing 
and  Plotting  Charts  for  Vacuum 
Tubes  Used  in  Radio  Reception 

Learning  Vacuum  Tube 
Characteristics 

By  H.  FRANK  HOPKINS 


The  Magazine  of  the  Hour 


11 


THERE  are  numerous  characteristics 
of  vacuum  tubes  used  in  radio  re- 
ception and  transmission  that  may 
be  determined,  but  which  have  no 
value  to  the  average  radio  fan.  How- 
ever, there  are  a  few  of  vital  import- 
ance to  all  users  of  vacuum  tubes  and 
it  is  the  writer's  intention  to  make  clear 
such  of  these  characteristics  which  are 
of  importance  to  the  fan  so  that  he 
will  be  able  to  plot  curves  or  charts 
and  match  his  tubes  as  easily  as  he 
tunes   his   receiving   set. 

The  equipment  required  for  this  work 
is  a  good  vacuum  tube  test  set,  such  as 
described  in  the  May  issue  of  RADIO 
AGE.  An  instrument  such  as  this 
may  be  built  at  a  nominal  cost  or  one 
similar  may  be  purchased  ready  made 
at  a  good  range  of  prices,  from  the 
simple  one-meter  affair  to  those  having 
a  complete   set  of   meters. 

The  One-Meter  Tester 

'"PHE  one  meter  tube  testers  are 
-*-  limited  in  their  use,  however,  and 
outside  of  a  plate  current  curve  at  a 
fixed  grid  bias,  no  other  features  may 
be   determined.      This   type   of   test   set 


will  only  give  a  fair  idea  of  how  a  tube 
will  act.  They  will  sometimes  show 
a  good  plate  current  curve,  but  fail 
to  perform  efficiently  when  in  opera- 
tion. Therefore,  it  is  worth  the  differ- 
ence in  price  to  have  a  set  that  will 
show  the  filament  current  or  voltage 
and  the  grid  bias  voltage  in  addition 
to  the  plate  current. 

For  this  article,  the  RADIO  AGE 
test  set  was  used.  It  consists  of  three 
meters;  a  filament  voltmeter,  a  grid 
volt  meter  and  a  plate  milliammeter 
with  the  necessary  resistances  to  vary 
the  filament  and  plate  voltage  and  grid 
bias  voltage  as  desired. 

It  was  prepared  for  operation  by 
connecting  an  "A"  or  filament  battery 
of  suitable  voltage  for  the  tube  under 
test — to  terminals  (A  BAT  +  )  and 
(A   BAT    -). 

A  "B"  or  plate  battery  of  ninety 
volts  was  connected  across  the  bind- 
ing posts  (B  — )  and  (B90)  with  taps 
at  22  J^  volts,  connected  to  binding 
post  (B22),  45  volts  to  binding  post 
(B4S),  and  67}^  volts  to  binding  post 
(B67),  Two  7  Y2  volt  "C"  or  grid 
batteries    were    connected    to    the    "C" 


The  milliameter  shown  above  shows  the 
plate  current  characteristic  in  milliamperes. 

battery  terminals.  The  negative  terminal 
of  one  connected  to  binding  post  (C  — ) 
the  positive  terminal  of  this  and  the 
negative  terminal  of  the  second  "C" 
battery     connected     to     binding     post 

(C-j )    and    the    positive    terminal    of 

the  second  "C"  battery  to  binding 
post    (C+). 

The  filament  rheostat  (R)  is  moved 
to  its  off  position,  a  tube  placed  in  the 
socket  (T)  and  the  set  is  ready  for 
operation.  By  moving  the  switch  (BS) 
to  point  ( — )  and  closing  switch  (GS) 
a  negative  grid  bias  voltage  will  be 
shown  on  the  two-scale  voltmeter  (GM), 
this  grid  bias  voltage  may  be  varied 
at  will  from  0  volts  to  7H  volts  by 
moving  the  potentiometer  (GP)  until 
the  meter  shows  the  desired  voltage. 
By  moving  the  switch  (BS)  to  the  (  +  ) 
point,  a  positive  grid  bias  will  be  shown 
on  the  meter  (GM)  and  will  be  varied 
as  above. 

The  switch  (PS)  and  the  rheostat 
(BR)  regulate  the  "B"  or  plate  battery 
voltage.  By  moving  the  switch  (PS) 
to  terminal  (1)  and  moving  the  rheo- 
stat   (BR)    a    plate    voltage    range   from 


Figs. 


1  and  2.      Fig.    1  shows  the  typical  curve  of  plate  current  voltage, 
characteristics,   the  result  of  tests  described  in 


while  Fig.  2  shows  the  typical  curves  of  grid  and  plate 
the  accompanying  article. 


12 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


The 


two-scale  voltmeter,  showing  the  grid 
bias  voltage. 


0  to  22  Yi  volts  is  obtained,  to  point 
(2)  from  22Y2  to  45  volts,  to  point  (3) 
from  45  to  67  ]4  volts  and  to  point  (4) 
from  67  >£  to  90  volts.  This  voltage 
is  read  on  the  meter  (PF)  by  moving 
the  transfer  switch  to  position  (4). 
The  filament  voltage  will  be  read  on 
the  same  meter  (PF)  by  moving  the 
transfer  switch  to  position  (3).  The 
filament  voltage  is  varied  by  the  rheo- 
stat (R). 

Plate  Current  Curve 

FOR  the  first  test,  we  will  use  a  3-4 
volt  199  type  of  tube — placed  in  the 
socket  (T)  by  use  of  an  adapter.  This 
is  a  high  vacuum  receiving  tube  with  the 
filament  normally  operating  at  3  volts 
and  a  filament  current  drain  of  .06 
amperes  or  60  milliamperes.  This  type  of 
tube  is  most  used  in  super-heterodyne 
receiving  sets  and  is  by  far  the  most 
critical  of  everyday  tubes. 

A  piece  of  cross  section  paper  will  be 
prepared  by  marking  the  plate  voltage 
scale  on  the  lower  edge  and  the  plate 
current  scale  on  the  left  edge  as  in  figure 
one.  The  filament  voltage  will  be  ad- 
justed to  a  point  just  below  3  volts, 
say  2.8  volts,  the  grid  will  have  a  0  volt 


negative  reading  on  the  meter  (6m)  and 
the  plate  voltage  will  be  adjusted  to  0 
volts. 

By  moving  the  rheostat  (BR)  the  plate 
voltage  is  increased.  A  reading  will  be 
taken  from  the  milliammeter  and  a  point 
corresponding  to  this  reading  and  the 
reading  of  the  plate  voltmeter  (PF)  will 
be  marked  on  the  cross  section  paper, 
as  in  the  chart  (figure  one).  This  reading 
— with  5  volts  on  the  plate,  showed  a 
plate  current  of  about  .1  milliampere. 
At  10  volts  it  read  practically  the  same, 
and  so  on,  gradually  until  20  volts  was 
applied  and  read  at  .3  milliampere.  At 
25  volts  the  plate  current  was  about  .5 
at  30  .7  and  at  40  it  was  1.2  milliamperes. 
It  increased  rapidly  until  90  volts  showed 
a  plate  current  of  about  4.3  milli- 
amperes— which  is  average  for  a  tube 
of  this  type. 

When  all  of  these  points  are  marked 
they  will  be  joined  by  a  line  running 
through  each,  and  a  completed  plate 
current  curve  as  in  figure  one  will  be 
made.  Simple,  isn't  it?  This  perform- 
ance may  be  repeated — on  the  same 
chart,  at  different  grid  bias  voltage — 
say  a  1  1-2  volt  negative  and  a  1  1-2 
volt  positive  bias,  thus  giving  a  complete 
plate  current  story  of  the  tube  at  various 
operating  conditions. 

Grid    Characteristic    Curves 

TO  make  a  grid  characteristic  curve — 
figure  2,  the  plate  voltage  will  be 
set  at  40  volts — the  grid  bias  voltage 
will  be  adjusted  until  the  meter  (GM) 
shows  0  with  the  switch  on  point  (+). 
The  reading  of  the  milliammeter  (MA) 
will  be  located  on  the  chart  as  before — 
and  readings  for  each  fraction  of  a  volt 
will  be  spotted — as  in  figure  two.  The 
40  volt  curve  showed  a  plate  current  of 
1.2  milliamperes  and  at  1  volt  (  +  )  it 
read  1.5  milliamperes  and  so  on  to  2 
volts  (+)  it  read  1.8  milliamperes.  Going 
back  to  0  volts  and  shifting  the  switch 
(BS)  to  a  negative  bias,  the  readings  were 
taken  the  same  as  above,  except  they  were 
inversely  proportional  to  the  grid  voltage, 


The    0-10,    0-100    scale    voltmeter,    which 
shows  the  filament   voltage  and  plate  volt- 
age, respectively. 

showing  1.2  milliamperes  at  0  volts 
negative  and  so  on  down  until  .1  milli- 
amperes was  obtained  at  slightly  over  4 
volts  negative  ^>ias. 

This  curve  will  show  the  best  "C" 
battery  voltage  or  grid  bias  for  a  tube  at 
various  plate  voltages,  and  it  may  not  be 
amiss  to  say  that  as  we  add  to  the  plate 
voltage,  the  higher  the  grid  bias  voltage 
may  be,  several  curves  may  be  made  on 
one  chart  for  this  characteristic  at 
various  plate  voltages,  as  shown  in 
Figure  four,  on  page  12  of  RADIO  AGE 
for  May,  1925. 

A  filament  voltage  curve  may  be 
made  and  a  filament  current  curve  also 
if  an  ammeter  is  included  in  the  test 
set.  This  will  be  plotted  from  periodic 
readings  as  in  the  other  curves,  and  will 
make  it  possible  to  show  an  emission 
curve  (Figure  3).  This  is  one  of  the 
factors  so  important  to  users  of  vacuum 
tubes,  as  the  life  of  a  tube  depends  upon 
the  proper  emission  of  the  electrons  from 
the  filament,  and  is  usually  ended  by  a 
decrease  -in  emission,  necessitating  ex- 
cessive filament  voltage  to  keep  it  in 
(Turn  to  page  53) 


Figs.  3  and  4.     Fi 


.  3  is  an  example  of  an  emission  curve,  as  described  in  Mr.  Hopkins'  article.    Fig.  4  reveals  the  difference 
between  a  good  tube  under  normal  operation  and  a  poor  tube  under  the  same  conditions. 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour  13 


How  Much  Coupling  is  Necessary? 


Coupling  can   be  construed  as  the  method  by  which  energy  is  transferred  from  one  circuit  to  another.      It  can  be  energy  from  the  antenna  to  the  detector 
tube;  energy  between  tubes  of  a  radio  frequency  amplifier,  or  again  audio  energy  passing  bettween  audio  stages.     Coupling  passes  the  energy  across  in  each  case. 

Big  Advantage  in  Having  a  Variable  Coupling  Scheme 
to  Enable  Adapting  the  Receiver  to  Different  Aerials; 
Suiting  Coupling  to  Varied  Wavelengths  a  Real  Problem 


COUPLING"  is  a  broad  term  in 
its  interpretation.  It  signifies  the 
method  by  which  energy  is 
transferred  from  one  radio  circuit  to 
another.  Whether  it  be  the  energy  from 
the  antenna  travelling  to  the  detector 
tube,  or  energy  being  transferred  between 
tubes  of  a  radio,  frequency  amplifier,  or 
still  again  the  audio  energy  passing  be- 
tween the  audio  stages — it  is  through 
coupling  that  the  energy  is  passed  across. 
To  have  coupling,  there  must  be  two 
associated  circuits  carrying  alternating 
current.  One  circuit  may  consist  largely 
of  inductance  (coil)  and  the  other 
largely  of  capacity  (condenser)  or  the 
coupling  may  even  exist  because  of  a 
resistance  which  is  common  to  both  of 
the  circuits.  The  sort  of  coupling  with 
which  we  must  deal  almost  exclusively  is 
that  due  to  associated  inductances  or 
coils.  And  inasmuch  as  the  coupled  coils 
wound  on  iron  cores  which  form  the 
commercial  audio  transformer  are  not 
to  be  adjusted,  our  discussion  will  be 
confined  to  radio  frequency  transformers. 

R.  F.   Coupling 

I"  ET  us  first  talk  about  the  coupling 
*-*  between  the  aeiial  system  and  the 
radio  receiving  set.  In  Fig.  1  two  methods 
whereby  this  coupling  is  accomplished 
are  illustrated.  The  type  of  "A"  is  per- 
haps more  common  and  it  possesses 
several  distinct  advantages.  In  the  first 
place,  the  separation  between  the  primary 
P  and  the  secondary  S  may  be  made 
fairly  great,  and  the  capacity  effect  of 
the  aeiial  upon  the  secondary  thereby 
minimized.  In  other  words,  a  receiver  so 
coupled  to  the  aerial  will  tune  almost  the 
same  on  any  aerial,  large  or  small. 

In  "B"  another  popular  scheme  is 
shown.  Here  there  is  really  a  trans- 
former as  in  "A"  with  two  distinct  wind- 
ings, but  a  portion  of  the  secondary  acts 
as  the  primary  also.  Here  the  coupling  is 
very  much  closer  than  in  "A"  for  the 
same  number  of  turns  included.  Its  dis- 
advantage lies  in  the  great  effect  of  the 
aerial's  capacity  upon  the  broadness  of 
the    secondary    tuning    condenser.        A 


By  BRAINARD  FOOTE 


large  aerial  will  increase  broadness  and  a 
small  aerial  will  reduce  it.  Slightly 
greater  volume  may  be  had  with  con- 
nection "B,"  however,  so  that  many 
listeners  prefer  it  even  though  it 
does  upset  the  dial  readings.  In  the  case 
of  a  set  like  the  neutrodyne,  the  three 
dials  do  not  read  the  same,  but  the  first 
one  is  lower  than  the  other  two. 

It  is  of  great  advantage  to  have  a 
variable  coupling  scheme  to  adapt  the 
set  to  different  aerials.  With  a  long 
aerial,  only  5  to  10  turns  are  needed  in 
coil  P,  but  with  a  very  small  aerial,  as 
many  as  15  or  20  may  be  used.  The 
dotted  line  in  "A"  shows  where  the  fila- 
ment circuit  is  grounded,  a  measure 
ordinarily  desirable  because  of  its  good 
effect  upon  inductive  noises  and  upon 
hand    capacity. 


Fig.  1 — The  aerial  is  coupled  to  the  set  by 
a  "coupling  coil."  This  may  be  a  separate 
winding  as  at  "A"  or  a  portion  of  the 
secondary  as  at  "B."  The  former  method 
is  better  in  most  cases.  The  aerial's  natural 
wavelength  must  be  kept  low  if  you  wish 
good  short-wave  as  well  as  long-wave  re- 
ception. 


A  coupler  as  in  "A"  may  be  wound  on 
one  piece  of  tubing,  with  a  primary  coil 
of  as  many  turns  as  are  necessary  for  the 
individual  case.  To  get  the  maximum  of 
volume  on  different  wavelengths,  a  small 
switch  might  be  provided  to  change  the 
number  of  turns,  as  follows: — short 
waves  5,  medium  waves  10  and  long 
waves  15  turns.  KSD  and  stations  of 
similar  wavelength  may  then  be  almost 
doubled  in  volume,  with  the  average  set. 
But  for  the  shorter  waves,  the  number  of 
turns  must  be  reduced  because  of  the 
absorption  effect  of  so  large  a  primary 
coil. 

Antenna  Wavelength 

'T'HE  aerial  system  has  a  "natural" 
-*-  wavelength  of  its  own,  which  must  be 
reckoned  with.  Users  of  tuned  R.  F.  or 
even  regenerative  receivers  with  aerials 
having  very  long  lead-ins  have  found 
certain  "dead  spots"  on  the  dial.  These 
are  caused  by  absorption  where  attempt 
is  made  to  tune  the  set  to  the  natural  of 
the  antenna.  This  natural  ought  to  be 
less  than  the  shortest  broadcast  wave- 
length received,  in  order  that  it  may  not 
interfere  seriously  with  short  wave 
reception.  To  smooth  out  such  a  dead 
spot  caused  by  a  lengthy  aerial  system, 
either  reduce  the  aerial's  capacity  or 
use  a  series  condenser  of  .00025  or  .0005 
mfds.  capacity.  The  simplest  method  of 
!  educing  the  capacity  of  the  antenna,  if 
it  is  too  long,  is  to  shorten  it.  Simply 
shortening  it,  however,  does  only  half 
the  job.  The  greatest  improvement 
comes  by  increasing  its  altitude.  An 
antenna  of  60  or  70  feet,  raised  20  feet 
above  a  roof,  is  far  superior  for  sensitiv- 
ity to  a  150  foot  aerial  only  five  feet  above 
the  roof.  Not  only  does  the  passing 
radio  wave  induce  more  voltage  in  the 
wires  because  of  their  greater  height,  but 
the  antenna's  natural  wavelength  is 
reduced  at  the  same  time. 

So  much  for  antenna  coupling.  We 
now  come  to  a  more  "ticklish"  coupler — 
that  which  transfers  energy  from  one 
R.  F.  amplifier  tube  to  another  one,  or 
to  the  detector.  (Turn  the  page) 


14 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour , 


Fig.  2 — How  radio  frequency  tubes  are  coupled  to  each  other.  At  "C"  is  the  universally 
popular  "fixed  primary"  type.  This,  however,  is  efficient  only  over  a  moderate  wave 
hand.      Varying  the  coupling  from  about   5   to   12  turns,  as  at  "B,"  gives  better  results 

on  all  wavelengths. 


In  Fig.  2,  "C,"  is  shown  such  a  coupler 
in  circuit  form.  The  secondary,  of  course, 
is  of  the  proper  size  to  cover  the  broad- 
cast band  in  conjunction  with  the  variable 
condenser  that  tunes  it.  The  primary  is 
as  large  as  possible,  but  not  so  large  that 
it  passes  sufficient  energy  back  to  the 
grid  to  cause  oscillation  of  the  tube.  In 
practise,  such  an  ideal  transformer  is  out 
of  the  question,  for  it  is  perfectly  efficient 
for  only  one  wavelength  or  a  very  narrow 
band  of  wavelengths. 

The  average  tuned  R.  F.  transformer  is 
of  this  type  and  is  so  constructed  that  its 
primary  does  not  feed  back  enough 
energy  to  cause  oscillation  on  the  shorter 
wavelengths.  For  this  reason,  it  is  not 
quite  as  efficient  as  it  might  be  on  longer 
waves.  This  peculiarity  accounts  for  the 
difficulty  many  tuned  R.  F.  receivers 
experience  in  getting  volume  from  long 
wave  stations  like  KYW,  KSD  and  the 
like,  whereas  stations  of  much  less  power 
on  the  shorter  waves  can  be  received  with 
enormous  volume,  by  comparison. 

Variable  Coupling 

OF  COURSE,  the  obvious  method  for 
getting  around  this  inequality  of 
wavelength  is  to  change  the  coupling, 
making  it  greater  on  longer  wavelengths. 
Shall  this  changing  be  accomplished  by 
a  moving  coil  whose  angular  relationship 
can  be  altered — like  a  ticklercoil?  Orshall 
we  have  a  permanently  set  winding,  with 
its  number  of  turns  controllable  by  a  tap 
switch?  The  first  method  is  better  from 
the  standpoint  of  uniformity  and  gradual 
movement,  but  it  has  a  big  disadvantage. 
The  capacity  coupling  is  changed  too 
much  and  causes  upsets  in  the  secondary 
dial  settings.  Besides,  there  are  too 
many  turns  on  the  coil  for  short  wave- 
lengths and  the  plate  circuit  is  tuned  so 
high  that  oscillation  commences. 

Hence  the  better  plan  is  to  provide  a 
tap  switch  for  cutting  in  or  out  the  prim- 
ary turns.  It  is  astonishing  what  an  im- 
mense difference  in  signal  volume  may 
be  had  with  such  a  device,  with  variable 
coupling  for  the  last  stage  of  the  radio 
frequency  amplifier,  or  between  the  R.  F. 


amplifier  and  detector  in  the  case  of  a 
single  step  amplifier.  By  this  method, 
the  R.  F.  coupling  is  as  great  as  possible 
without  causing  oscillations  and  the 
volume  as  well  as  the  selectivity  are  very 
much  greater. 

In  "D,"  Fig.  2,  is  shown  the  variable 
primary  coupler.  Here  a  tap  switch  is 
connected  to  change  the  coupling  for 
long  and  short  waves.  Such  a  plan  is  of 
most  value  in  sets  having  only  one  stage 
of  tuned  radio  frequency  and  a  detector, 
either  crystal  or  tube.  With  the  average 
coupling  coil,  a  fixed  primary  of  about 
6  to  8  turns  is  adopted.  Many  tuned  R.  F. 
reflex  sets  are  made  up  in"  this  manner. 
If  they  are  good  for  long  waves,  oscilla- 
tions prevent  good  reception  on  short 
waves,  and  if  excellent  on  short  waves, 
the  long  wave  stations  come  in  poorly, 
although  with  no  trace  of  oscillation. 


Fig.  3 — Details  of  a  variable  coupler. 
Primary  and  secondary  are  fairly  well  sep- 
arated, to  avoid  capacitative  coupling.  A. 
sub-panel  tap  switch  permits  the  use  of  any 
desired  number  of  turns  in  the  primary. 
White  dots  on  the  panel  show  where  the 
lever  is  to  be  set. 


Perhaps  the  easiest  method  of  adopt- 
ing the  variable  primary  is  to  install  a 
number  of  switch  points  and  a  switch 
knob  and  lever  on  the  panel,  where  it  i- 
readily  accessible  from  the  R.  F.  trans- 
former in  the  set.  This,  however,  requires 
long  connecting  leads  and  is  unsightly  in 
view  of  modern  receiver  construction. 
A  superior  method  is  indicated  in  Fig.  3. 
At  "A"  the  coupler  itself  is  pictured, 
"G"  and  "F"  being  the  secondary 
terminals.  The  smaller  winding  is  the 
primary  and  it  consists  of  approximately 
15  turns.  With  a  crystal  detector,  it  may 
be  advisable  to  go  as  high  as  20  turns, 
although  no  more  than  this  are  needed  if 
the  R.  F.  amplifier  tubes  are  good  ones. 

For  the  average  set  used  chiefly  for 
local  reception,  the  switch  may  have 
three  taps  and  the  entire  primary  have 
only  twelve  turns  in  all.  A  tap  is  taken 
at  the  7th  turn,  at  the  9th  and  at  the 
12th.  In  sets  using  two  stages  of  radio, 
the  primary  may  be  smaller,  even  for  DX 
work,  some  primary  coils  working  well 
with  a  total  of  ten  turns,  tapped  at  the 
5th  and  8th  and  10th.  The  number  of 
turns  in  the  primary  must  really  be 
worked  out  by  the  individual  set  opera- 
tor to  fit  his  own  conditions. 

Back-Panel 

HPHE  switch  points  are  laid  out  on  a 
■*•  small  piece  of  panel  material,  about 
2  inches  square.  The  switch  lever  may 
be  of  the  regular  style  or  be  cut  from 
spring  brass  or  phosphor  bronze.  It  is 
soldered  to  a  X-inch  set  collar.  Good 
contact  to  the*  lever  may  be  made  by 
using  a  long  set  screw  and  attaching  a 
nut  to  it  for  holding  the  end  of  a  short 
piece  of  flexible  wire.  This  forms  the 
plate  connection  "P  of  the  transformer. 
The  taps  are  laid  out  and  so  connected 
that  a  left-to-right  movement  of  the 
panel  knob  brings  an  increase  in  coupling. 
The  set  collar  is  attached  to  a  length  of 
bakelite  or  brass  rod,  M-inch  diameter, 
which  passes  through  a  M-inch  hole  in 
the  sub-panel  and  also  in  the  main 
panel.  The  assembly  is  given  at  "C" 
and  at  "B"  the  front  panel  is  shown. 
Three  small  white  dots  indicate  the  posi- 
tion of  the  switch  arm.  These  are  made 
by  filling  with  white  wax  crayon  small 
depressions  made  with  the  twist  drill. 

In  case  there  is  special  interest  in  DX 
reception,  more  taps  are  taken,  thus  giv- 
ing a  more  gradual  change  in  coupling. 
The  best  way  to  determine  how  the  pri- 
mary should  be  wound  is  to  make  up  an 
experimental  primary  coil  of  about  20 
turns,  with  a  tap  at  every  second  turn. 
The  taps  are  merely  bared  places  in  the 
wire,  twisted  into  loops.  A  spring  clip 
is  then  used  to  connect  to  the  taps  in 
lieu  of  the  switch  arm  and  points. 

In  most  cases,  the  final  result  will  be  a 
coil  of  about  twelve  turns,  with  taps 
at  the  5th,  7th,  8th,  9th,  10th  and  12th 
turns,  or  about  six  taps  in  all.  The 
adjustments  should  be  tested  with  good 
"B"  batteries  of  at  least  90  and  prefer- 
ably a  little  higher  voltage,  with  good 
R.  F.  amplifier  tubes  and  the  coupling 
coils  properly  in  place  with  about  1-4 
inch  separation  between  the  primary 
and  secondary. 

(Turn  to  page  50) 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


15 


'THE  receiving 

-*•  system  to  be 
described  in  this 
paper  is  the  result  of 
a  very  considerable 
amount  of  research 
and  experiment  put 
forth  in  an  endeavor 
to  produce  a  super- 
heterodyne that 
would  give  equal  or 
better  results  than 
could  be  obtained 
with  any  existing 
type,  yet  which 
would  employ  a 
maximum  of  six 
tubes,  for  this  num- 
ber must  certainly 
be  considered  the 
maximum  allowable 
limit  henceforth,  if 
the  word  "efficien- 
cy" be  used  in  con- 
nection with  this 
system  of  reception. 
In  the  past,  there 
has  been  no  ques- 
tion in  the  mind  of 
even  the  most  un- 
informed fan  but 
that  the  super-het- 
erodyne was  the 
ideal  radio  receiver, 
and  the  ultimate  de- 
sire of  every  enthu- 
siast has  been  to  be 
the  proud  owner -of 
a  '  set  containing 
many  more  brightly 
lit  tubes  than  any 
other  set  in  his  com- 
munity. Yet  this 
has  been  the  real 
drawback     of     the 

super;  the  necessity  of  using  from  seven  to 
ten  tubes  in  order  to  obtain  truly  super- 
heterodyne results.  Therefore,  the  aim  of 
receiver  designers  has  not  been  to  improve 
results,  for  a  super  that  really  justifies  the 
name  will  go  down  to  the  lowest  noise-level 
— the  limit  of  practical  sensitivity;  but 
rather,  to  reduce  the  number  of  tubes  used 
and  at  the  same  time  retain  the  sensitiv- 
ity, selectivity  and  quality  of  reproduc- 
tion obtainable  with  the  best  of  sets. 

Two  Ways  To  Do  It 

rT,0  the  mind  of  the  engineer,  there  are 
-*-  but  two  practical  methods  of  attack- 
ing this  problem;  either  make  the  tubes 
used  do  more  work,  or  raise  the  efficiency 
of  each  circuit  of  the  receiver  right  up 
to  the  maximum  limit,  or  do  both  simul- 
taneously. The  first  method  of  attack 
may  be  considered  an  expedient,  and 
boils  down  to  reflexing,  causing  one  or 
more  tubes  to  perform  various  functions, 
such  as  radio  and  audio  amplification 
simultaneously.  This  is  not  entirely 
practical,  in  view  of  the  frequencies  to 
be  handled,  except  in  one  section — the 
frequency  changer.  Here,  there  is  no 
reason  why  one  tube  may  not  be  used  for 
the  first  detector  and  oscillator,  provid- 
ing the  separate  tuning  circuits  may  be 
satisfactorily  isolated.  Up  to  the  present, 
this  has  been  impossible,  except  by  the 
second  harmonic  method,  which  will  be 
considered  later. 


A  Big  Step  Toward  Efficiency 
in  Super-Heterodyne  Design 

A  SIX  TUBE 

"SUPER- AUTODYNE' ' 

RECEIVER 

The  Super-Het  Reduced  to  Six  Tubes,  Yet  Giving 
Results   More   Efficient  .Than   Seven   and  Eight 

By  McMURDO  SILVER 


Fig.  1. 


The  completed  super-autodyne    illustrating  clearly  what  can  be  done  with  standard  circuits  in  producing 
a  symmetrical  design  that  is  pleasing  to  the  eye. 


The  next  method,  and  the  more 
straight-forward  one,  is  to  improve  the 
efficiency  of  each  section  of  the  system 
so  that  fewer  tubes  will  be  required  to 
give  the  same  amplification  that  has 
hitherto  been  obtained.  An  example  of 
such  a  receiver  was  described  by  the 
author  in  the  March  issue  of  RADIO 
AGE.  This  set  incorporated  a  regenera- 
tive I  first  detector,  thus  giving  the 
greatest    possible    gain     obtainable    for 


A  REMARKABLE 

ROUND-UP  OF 

HOOKUPS 

The  August  RADIO  AGE 
will  be  the  most  unusual 
issue  of  a  radio  magazine 
ever  printed.  It  will  con- 
sist of  more  than  100  pages 
of  basic  radio  hookups  from 
crystal  to  super-het,  illus- 
trated with  actual  color 
RADIO  AGE  blueprints. 
Don't  miss  this  wonder 
issue. 

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the  input  circuit. 
But  two  stages  of 
intermediate  fre- 
quency amplifica- 
tion were  used,  for 
due  to  the  careful 
design  of  the  trans- 
formersemployed,  it 
was  found  possible 
to  realize  as  much 
amplification  with 
two  stages  as  had 
previously  been 
realized  with  three 
stages.  In  each  cir- 
cuit, efficiency  had 
been  increased  as 
much  as  possible, 
and  the  fact  that 
with  but  seven  tubes 
receivers  of  this  type 
give  a  fairly  consis- 
tent range  of  two  to 
three  thousand 
loud-speaker  miles, 
even  under  present 
weather  conditions, 
is  probably  the  best 
indication  that  this 
latter  method  of  at- 
tacking the  problem 
is  the  most  logical 
one. 

A  Practical 
Combination 

THE  next  step 
was  obviously  to 
combine  the  de- 
tector and  oscillator 
functions  in  one 
tube.  The  difficulty 
which  has  hereto- 
fore prevented  the 
use  of  one  tube  for 
both  detector  and  oscillator  has  been  that 
of  isolating  the  loop  or  pickup  circuit 
from  the  local  oscillator  circuit.  It  has 
been  impossible  to  couple  a  tuned  pickup 
circuit  to  a  tuned  oscillator  when  the  two 
are  to  operate  but  fifty  or  sixty  kilocycles 
apart  throughout  the  broadcast  wave- 
length range,  and  not  have  the  tuning  of 
one  section  react  on  that  of  the  other. 

Armstrong  and  Houck  developed  the 
expedient  of  the  second  harmonic  system, 
whereby  the  oscillator,  working  at  double 
the  desired  wave,  did  not  react  greatly 
upon  the  loop  circuit.  Then,  a  harmonic 
of  the  oscillator  was  used  for  heterodyn- 
ing. This  meant  two  waves  were  being 
produced  by  the  oscillator  of  sufficient 
power  to  cause  radiation,  which  neces- 
sitated the  use  of  a  muffler  tube  ahead 
of  the  detector-oscillator  to  prevent 
radiation.  Thus,  two  tubes  were  still 
used,  though  the  gain  in  signal  strength 
was  equal  to  or  slightly  better  than  that 
obtained  with  a  good  regenerative  detec- 
tor and  oscillator.  At  best,  the  system 
is  not  entirely  satisfactory  for  home 
assembly. 

Then  came  the  development  by  J.  H. 
Pressley,  a  Signal  Corps  engineer,  of  the 
balanced  autodyne  circuit,  which  not 
only  performs  the  required  function  with 
one  tube,  but  does  it  much  better  than 
either  the  second  harmonic  autodyne, 
with  its  amplifying  muffler,  or  what  has 
hitherto  been  considered  about  the  limit 


16 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


3s  Star         o»      c 


Fig.  2.      Interior  view  of  the  super-autodyne .      The  instrument  designations  will  be 

found  in  the  text.     The  sockets,  from  left  to  right,  are:     VI,  autodyne;  V2,  1st  R.  F.; 

V3,  2nd  R.  F.;  V4,  2nd  Det.;  V5,  1st  A.  F.;  V6,  2nd  A.  F.;    Socket  shelves  may  also 

be  procured  for   UV199  or  C299  tubes. 


for  sensitivity — the  regenerative  detec- 
tor and  separate  oscillator.  This  auto- 
dyne circuit,  in  actual  tests,  appears 
to  give  a  much  greater  gain  than  any  of 
the  frequency-changing  circuits  previous- 
ly utilized,  and,  at  the  same  time,  is  far 
simpler  to  build  and  operate  than  any 
of    its    predecessors. 

The  Circuit 

THE  actual  first  tube  circuit  is  shown 
in  Figure  4.  The  coils  L2,  L3  are 
theoretically  equal,  as  are  the  condensers 
CX,  CX.  Actually,  they  cannot  be 
made  fixed  and  equal,  so  CX,  CX  are 
made  adjustable,  to  obtain  substantially 
a  condition  of  equality.  These  units 
make  up  a  bridge  circuit,  shown  by  the 
heavy  lines.  Since  L2  equals  L3,  the 
potential  across  them  is  equal,  so  that 
it  is  also  equal  between  points  3  and  4, 
and  5  and  6.  Likewise,  the  potential 
across  CX  and  CX  is  equal.  Since  the 
potential  across  3  and  6  is  the  same  for 
both  inductance  and  capacity,  then 
points  4,  S  and  the  joint  between  CX,  CX 
are  at  equal  potential,  and  are  also 
theoretically  at  zero  potential,  since 
these  points  are  neutral  with  respect 
to  3  and  6.  Then,  circuit  Bl,  C2,  B2, 
may  be  connected  at  these  neutral  points, 
with  substantially  no  reaction  on  the 
frequency  of  the  bridge  circuit.  Further, 
as  these  points  are  neutral  with  respect 
to  3  and  6,  no  energy  in  the  bridge  cir- 
cuit can  get  into  Bl,  C2,  B2,  since  there 
is  no  potential  difference  across  these 
points  of  the  bridge.  Therefore,  the 
frequency  adjustment  of  the  bridge  cir- 
cuit cannot  react  upon  that  of  the  Bl, 
C2,   B2,  circuit,  and  vice  versa. 

Since  the  signal  is  fed  from  the  loop 
and  its  tuning  condenser  to  the  oscillator, 
it  will  divide  equally  across  the  bridge 
arms.  If  a  tube  detector  is  connected 
across  one  capacity  CX,  the  drop  in 
potential  may  be  used  to  cause  rectifica- 
tion. It  would  appear  that  some  of  the 
signal  voltage  is  lost  by  this  method, 
but  actually  it  is  not.  It  is,  as  a  matter 
of  fact,  considerably  reinforced  when 
the  new  component  is  finally  fed  to  the 
amplifier,  probably  due  to  regenerative 
amplification.  The  coil  LI,  coupled  to 
L2,  L3,  causes  the  bridge  circuit  to 
oscillate   at   a   frequency   determined  by 


these  coils,  CX,  CX  and  CI,  which  is 
made  variable  for  the  purpose  of  tuning 
the  oscillator  circuit.  As  previously 
explained,  this  energy  cannot  get  into 
the  loop  circuit,  so  radiation  is  confined 
to  what  may  be  experienced  from  the 
oscillator  coil  system  itself — a  negligible 
amount.  By  means  of  this  circuit,  which 
is  surprisingly  efficient  when  it  is  con- 
sidered that  one  tube  delivers  a  stronger 
signal  than  two  tubes  in  the  conventional 
circuit,  and  is  consequently  much  more 
sensitive,  it  is  possible  to  eliminate  one 
tube  from  the  receiver,  and  still  obtain 
better  results  than   with   two. 

The  intermediate  amplifier  is  the  only 
other  unusual  feature  of  the  receiver. 
It  employs  but  two  stages  and  is  on  the 
order  of  those  described  by  the  writer 
in  RADIO  AGE  for  March,  1925.  It 
differs,  however,  in  that  it  employs 
special  laboratory  charted  transformers 
which  are  a  compromise  between  the 
extreme  selectivity  of  properly  designed 
air-core  coils,  and  the  great  stability 
and  amplification  of  good  iron  core  trans- 
formers. But  two  core  laminations  are 
used  in  each  transformer,  of  7  mill 
silicon  steel,  one  in  the  shape  of  an  "F" 
and  one  an  "L."  The  air  gap  formed, 
together  with  other  recently  developed 
features  of  the  design,  permits  the  realiza- 
tion   of    almost    an    ideal    curve — extra- 


ordinarily high  amplification  over  a 
10,000  cycle  band,  with  a  sharp  cutoff 
either  side.  The  amplifier,  employing 
two  of  these  transformers,  together  with 
a  sharply  tuned  filter  which  is  provided 
with  a  laboratory  adjusted  tuning  ca- 
pacity, C5,  gives  tremendous  amplifica- 
tion, for  it  also  employs  controlled  re- 
generation, adjustable  by  means  of  R3. 

More  Stages  Unnecessary 

VXTHILE  more  than  two  stages  mfght 
»  '  be  employed,  two  will  go  down  to 
the  best  noise  level,  so  that  more  are 
unnecessary.  Further,  there  is  a  decided 
drop  in  amplification  in  adding  more 
stages,  which  will  react  upon  the  pre- 
ceding two,  so  that  three  stages  give 
only  slightly  better  results  than  two. 
This  should  really  be  written  "slightly 
more  noise,"  for  two  stages  give  more 
than   enough    gain. 

Before  going  into  a  description  of  a 
receiver  designed  along  the  lines  out- 
lined, it  might  be  well  to  justify  the  use 
of  the  name  "super-autodyne."  "Hetero- 
dyne" is  generally  considered  to  refer 
to  a  source  of  external  power — a  separate 
detector  and  oscillator  tube.  "Auto- 
dyne" refers  commonly  to  a  tube  per- 
forming the  functions  of  rectification 
and  oscillation  simultaneously,  so  it  was 
considered  logical  to  call  the  six  tube  re- 
ceiver a  "super-autodyne" — and  it  cer- 
tainly deserves  the  appellation,  "super," 
for  the  results  obtainable  are  surprising. 

Below  is  a  log,  representing  one  hour's 
work  by  an  operator  unfamiliar  with  the 
system.  The  set  was  located  600  feet 
from  WGN,  one-half  mile  from  KYW, 
and  WMAQ,  and  many  other  Chicago 
locals  were  also  operating.  All  stations 
were  heard  on  the  loud-speaker. 


WCEE 

19 

4S.5 

8 

KSUO 

67.5 

78 

T, 

WTAS 

23 

61 

H 

WCED 

29 

23 

T, 

KDKA 

23.5 

65 

H 

WHAZ 

33 

30 

I, 

WGR 

31 

71 

H 

WLW 

42 

41 

r, 

WDAF 

31.5 

21 

1. 

WTAC 

50.5 

54 

T. 

WTAM 

36 

31 

JL 

KFI 

49.5 

53 

i, 

KSID   . 

36.5 

33.5 

1, 

KStTI 

48 

32 

i, 

WCCO 

40.5 

39 

1. 

WQJ 

50 

45 

i, 

WOS 

44.5 

45 

1. 

WTAY 

16 

37 

H 

WCAP 

50 

53 

1, 

WBCN 

18 

43 

H 

WSUI 

53 

58 

1, 

WJJD 

22.5 

61 

a 

WEAF 

55.5 

58 

1, 

WLS 

28 

85 

s 

WCX 

60.5 

67 

1, 

WBAP 

52 

56 

T, 

WOAW 

63 

70 

1, 

WEBH 

32 

95 

s 

WGN 

32 

28 

L 

The  station  separation  was  very  pleas- 
ing on  some  of  the  unlisted  lower  wave 
stations,  due  to  the  use  of  the  straight- 
line-wavelength  condensers.  A  compari- 
son   with    a    standard    five-tube    neutro- 


Bottom  view  of  the  socket  shelf  assembly.      Notice  how  all  parts  are  rigidly 
fastened  in  place — an  important  feature  for  portable  receivers. 


RADIO  AGE  for  July,  1925 

dyne  on  a  100  foot  antenna  was  unfavor- 
able to  the  neutrodyne  both  on  the  count 
of  selectivity  as  well  as  sensitivity  and 
volume.  A  standard  super  (see  March 
RADIO  AGE)  failed  to  produce  any 
better  results,  as  did  another  eight-tube 
set  employing  air-core  transformers. 

While  the  outfit  will  deliver  about  the 
same  energy  with  either  dry  cell  or  stor- 
age battery  tubes,  the  dry  cell  tubes 
will  generally  be  sadly  over-loaded,  and 
it  is,  therefore,  suggested  that  UV-201-A 
tubes  be  used  throughout,  although 
even  so,  it  is  possible  to  overload  the 
sixth  tube.  This  will  be  appreciated 
when  it  is  realized  that  in  Chicago  it  is 
possible  to  get  volume  sufficient  for 
dancing  from  the  West  Coast  stations 
on  five  tubes  using  only  a  small  loop, 
under  favorable  conditions. 

The  portability  of  the  set  may  be 
realized  even  with  storage  battery  tubes 
by  means  of  special  leads  if  a  car  is 
handy.  These  leads  permit  connection 
to  the  car  battery  through  the  dash- 
board light  socket  for  the  "A"  supply. 
If  this  is  not  possible,  it  is  suggested 
that  the  necessary  dry  batteries  be  car- 
ried in  an  old  hand  satchel,  or  even  a 
lunch  box  or  tool  kit.  Then  connec- 
tions can  be  made  quickly  with  the 
color  cable  used  for  the  battery  leads, 
and  the  receiver  set  up  in  a  few  sec- 
onds' time.  This  battery  can  also  easily 
contain  the  folded  loop  and  a  small 
speaker,  when  they  are  not  in  use. 
Blanket  straps  will  provide  an  easy 
means  of  carrying  the  receiver,  so  that 
the  whole  set  can  readily  be  managed  by 
one  man. 

Portable  or  Permanent 

THE  advantage  of  this  arrangement 
is  that  the  same  set  serves  for  camp- 
ing or  traveling  that  is  used  to  provide 
entertainment  at  home  at  other  times. 
It  is  possible,  if  the  builder  prefers,  to 
have  a  luggage  shop  make  a  carrying 
case  so  arranged  that  the  receiver  is  at 
the  top,  the  batteries  below,  and  the 
loud  speaker  in  the  lower  compartment 
with  them,  either  at  the  side  or  in   the 


The  Magazine  of  the  Hour 


17 


middle.  A  small  speaker  is  to  be  recom- 
mended for  its  small  size  and  general 
portability,  and  it  certainly  talks  up 
very  much  "bigger"  than  it  looks. 

The  material  required  to  build  this 
received  is  listed  below,  with  the  designa- 
tion letters  used  in  the  diagrams  and  cuts 
following  the  quantity  of  each  item 
required.  While  it  is  entirely  permissible 
to  substitute  any  other  standard  parts 
for  those  listed,  it  is  strongly  recom- 
mended that  the  parts  specified  be  used 
for  several  reasons.  The  actual  space 
available  is  such  that  parts  of  larger 
or  different  dimensions  could  not  be 
substituted  in  some  instances,  and  in  the 
case  of  the  RF  Transformers,  and  SLW 
condenser,  it  would  be  inadvisable  to 
substitute,  since  the  results  of  the  receiver 
depend  in  a  large  measure  upon  the  use 
of  the  types  recommended. 

2  Cl,  C2— S.  L.  W.  Condensers. 

2  4"  Moulded  dials,  vernier  type  preferably 
1  R4  6  ohm  rheostat 

1  R3  240  ohm  potentiometer 

3  BL.  B2,  B3  insulated  top  binding  posts 
1  J2  101  jack  U-spring) 

1  Jl  102-A  jack  (3-spring) 

1  C-5.  211  filter  with  matched  tuning  capacity 

2  210.  210  charted  intermedi  ite  transformers 
1  LI.  L2.  L3.  coupling  unit 

1  6  gang  socket  shelf  C536-201-A,  No.  537-109) 

2  Tl.  T2.  3%:\  or  2.1  transformers 
2  C7,  CS  .5  condensers 

2  C3-C4  .00025  condensers  with  clips 
2  C9.  C10  .002  Condensers 

1  C6  .0075  condensers 

2  CX.  CX  .000025  condensers 
1  Rl  .5  Meg  teak 

1  R2  2  meg  leak 

1  SI  No-  3  jack  switch  (S.  P.  D.  T  I 
1  S2  S630  switch  (S.  P.  S.  T.) 
1  No.  701  color  cable  (5  leads) 
1  pair  No.  S629  shelf  brackets 
1  Bakelite  Panel.  7"xl8"xJ-8" 
Small  parts:  29  6/32  R.  H.  C.  P.  Machine  screws  X " 
2  6/32  R.  H.  N.  P.  Machine  screws  IK" 
31  6/32  nuts,  1 -spaghetti.  10-bus-bar.  £5-lugs 
Tools  required: 

1  hand-drill  with  drills  and  counter-sink 
1  soldering   iron   with    rosin-core   solder   and   non-corrosive 

1  sidi 


pliers 
1  screw  driver 

Inspecting  the  Set 

AS  SOON  as  the  material  has  been 
procured,  each  item  shoud  be  care- 
fully examined  to  see  that  all  screws 
and  nuts  are  tight,  and  lugs  placed  as 
shown  in  the  photographs,  so  that  those 
on  the  various  instruments  will  point  in 
the  best  directions  for  short  leads. 
Socket  springs  should  be  bent  up  to  make 
good  contact  with  tube  pins.  Condenser 
bearings  should  be  adjusted  to  give  the 
desired  tension. 


The  actual  assembly  of  the  receiver 
is  extremely  simple,  providing  a  standard 
socket  gang  and  a  drilled  panel  are  used. 
If  this  is  not  done,  it  will  be  necessary 
to  drill  up  a  sub-base  and  panel  to  take 
the  instruments.  The  panel  may  be 
grained  if  desired  by  rubbing  with  fine 
sandpaper  and  oil  until  all  traces  of  the 
original  finish  has  been  removed.  In- 
dicating marks  for  the  condensers  can 
be  scratched  with  a  scriber  and  filled 
with  white. 

If  Figures  2  and  3  are  carefully  studied, 
no  difficulty  should  be  encountered  in 
mounting  all  the  parts,  following  the 
designations  shown,  which  are  also 
given  in  the  parts  list.  As  the  parts 
are  mounted,  the  wiring  may  be  started 
and  put  in  progressively  on  the  base 
and  panel,  then  the  two  joined  together 
and  the  final  connections  made.  It  is 
necessary  to  use  a  well-tinned  soldering 
iron,  with  rosin  core  solder  and  some 
non-corrosive  paste.  The  battery  leads 
are  brought  out  through  a  color  cable, 
coded  in  accordance  with  the  A.  M.  E.  S. 
code,  thus  obviating  binding  posts  and 
providing  permanently  attached  con- 
necting leads  at  one  operation. 

After  the  receiver  has  been  wired,  the 
necessary  batteries  should  be  connected 
to  it,  the  rheostat  just  turned  on,  and 
the  autodyne  tube  inserted  in  its  socket. 
The  phones  must  be  connected  to  the  set, 
the  switch  SI  set  at  "L,"  Cl  at  40,  and 
C2    varied  rapidly  throughout  its  scale. 

A  "plunk"  will  be  heard,  indicating 
an  unbalanced  bridge  circuit.  With 
one  condenser  CX  set  all  in,  turn  the 
other  CX  slowly  out,  rotating  C2,  mean- 
while. If  the  plunk  does  not  disappear, 
reverse  the  operation,  leaving  the  other 
balancing  condenser  all  in  to  start  with. 
Once  the  plunk  has  been  balanced  out 
for  all  settings  of  Cl  and  C2,  condensers 
CX,  CX  should  never  be  touched.  If 
squealing  or  clicking  is  experienced  at 
low  settings  of  Cl,  it  will  be  necessary 
to  use  a  smaller  grid  leak  at  Rl.  This 
leak  will  generally  vary  between  .25 
and  .5  megohms. 


Fig.  4.     The  wiring  diagram  of  the  new  super-autodyne  receiver.     Heretofore  to  obtain  neutrodyne  results  on  a  loop  aerial,  seven 
and  eight  tubes  were  necessary.    But  in  this  receiver  only  six  tubes  are  needed  to  achieve  the  same  end. 


18 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Vacuum    Tubes   as 


PETER 
I.  WOLD 


IN  THESE  days  all  of  us  have  be- 
come so  well  acquainted  with  Vacuum 
tubes,  through  actual  use  or  through 
the  countless  articles  on  radio  sets 
making  use  of  them,  that  anything 
further  might  almost  seem  superfluous. 
On  the  other  hand,  there  may  be  some 
who  have  only  recently  acquired  an 
interest  in  radio,  or  it  may  be  that  the 
exceedingly  versatile  device  very  com- 
monly but  very  poorly  called  a  vacuum 
tube  offers  some  point  of  view  which 
may  be  new  to  many. 

If  you  have  followed  the  radio  art 
for  some  time,  you  have  heard  of  these 
tubes  being  used  in  a  number  of  dif- 
ferent ways,  as  for  audio  frequency 
amplification,  radio  frequency  amplifica- 
tion, detection,  regeneration,  reflex  re- 
generation, any  or  all  of  these  occurring 
in  your  receiving  sets;  and  if 
your  interest  carries  over  to 
the  broadcasting  station,  you 
have  heard  of  oscillation 
generators  and  modulation. 

All  of  these  terms  may 
suggest  a  confusing  variety 
of  uses  for  the  vacuum 
tube,  but  it  may  simplify 
matters  if  it  is  pointed  out 
that  this  tube  has  two 
functions  only,  which  are 
separate  and  distinct,  and 
the  various  uses  mentioned 
come  under  the  one  or  the 
other.  These  two  functions 
may  be  spoken  of  as  the 
repeating  function  and  as  the 
distorting  function.  The  two 
are  present  in  every  tube  in 
an  amount  depending  on  the 
design  of  the  tube;  i.  e.,  the 
relative  sizes  and  spacing  of 
the  elements  in  the  tube. 
By  the  way  in  which  the 
tube  is  operated,  and  by  the 
circuit  with  which  it  is  asso- 
ciated, one  of  these  functions 
may  be  emphasized. 


peating  electrical  variations  impressed  on 
the  grid  generally  with  amplification  and, 
at  least  theoretically,  faithfully,  or  with- 
out any  distortion.  By  the  second,  I  refer 
to  that  property  of  the  tube  by  which 
electrical  variations  on  the  grid  result 
in  variations,  generally  amplified,  which 
are  substantially  different.  As  an  ex- 
ample of  the  first,  we  may  take  the 
relaying  of  telephone  messages  across 
a  transcontinental  line  in  which  the 
greatest  precautions  are  taken  to  make 
the  repeating  action  as  faithful  as  possi- 
ble; i.  e.,  to  reduce  distortion  to  a  mini- 
mum. As  an  example  of  the  second, 
we  may  take  the  detection  of  a  radio 
message  in  which  electrical  oscillations 
or  variations  of  perhaps  a  million 
cycles — and  therefore  quite  inaudible 
— are    so    distorted    or    converted    as   to 


Devices 

Some  Interesting  Sidelights  on 
The  Repeating  Function  and 
"Distorting"  Function  of  Tubes 


B 


What  It  All  Means 

Y  the  first  of  these   func- 
tions. I  mean  that  of  re- 


Fig.  /.      A  typical  grid  characteristic  chart  for  199  type  (3  volt) 
tubes  with  plate  voltages  of  45-80  and  90  volts. 


give  oscillations  of  an  audible  frequency. 
The  repeating  action  of  the  tube  and 
its  circuit,  with  amplification,  would 
probably  be  held  to  be  the  more  impor- 
tant property,-  for  it  includes  such 
applications  as  long  distance  telephony 
and  all  the  actions  in  radio  work  men- 
tioned above,  except  those  of  detection 
and  modulation.  On  the  other  hand, 
its  property  as  a  distortion  device  is  the 
more  interesting,  though  not  so  gen- 
erally  understood. 

Let  me  remind  you  for  a  moment  of 
the  essential  elements  of  the  standard 
vacuum  tube.  There  is  a  filament 
which  may  be  raised  to  a  high  tempera- 
ture, whereupon  it  may  give  off  electrons 
— those  smallest  particles  of  matter  or 
electricity  which  we  have  come  to 
recognize  as  playing  so  important  a 
part  in  all  our  affairs.  Then 
there  is  a  plate  kept  at  a 
positive  potential  by  the  B 
battery,  and  which  therefore 
attracts  the  electrons  from 
the  filament,  thus  giving  rise 
to  an  electric  current  to  the 
plate.  Finally,  there  is  the 
grid  placed  between  the  two. 
When  the  grid  is  made  more 
positive,  a  larger  current 
flows  to  the  plate  and 
through  its  circuit,  and  when 
it  becomes  more  negative 
a  smaller  current  flows.  It 
is  possible  thus  to  control  a 
current  by  changing  the 
potential  of  the  grid;  and  the 
important  point  is  that  the 
energy  for  exercising  this 
control  may  be  very  much 
less  than  the  energy  of  the 
controlled  current.  It  is  for 
this  reason  that  the  device 
acts  as  an  amplifier. 

Getting  Minimum  Dis- 
tortion 

IF,  starting  with  a  small 
current  to  the  plate,  you 
draw  a  line  showing  how  this 
current  changes  as  the  poten- 
tial of  the   (Turn  to  page  60) 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


19 


The  Correct  ^B  '  Battery  for  your  Portable 


Success 
or 

Failure 
of  the 
Vacation 
Radio 
Depends 
on  the 
Condition 
of  Your 
"B"  Battery 
Outfit 


Liberal 
Supply 
at  Start 
Will 
Insure 
Success 


By  Edgar  H. 
Felix 


THE  B  battery  is  the  power  plant  of 
your  radio  set  and  its  failure  means 
that  the  portable  is  temporarily 
useless.  At  home,  batteries  are  not 
difficult  to  replace  from  the  liberally 
stocked  shelves  of  a  nearby  radio  store, 
but  in  the  wild  and  woolly  haunts  where 
many  of  us  seek  rest  from  the  rigors  of 
city  life,  B  batteries  are  as  rare  as  the 
proverbial  dinosaur. 

Hence,  give  this  important  element  of 
your  Summer  radio  set  all  of  the  consider- 
ation which  it  deserves.  Take  the  same 
precautions  that  you  would  before  start- 
ing on  a  motor  trip  across  a  hundred 
mile  desert — make 
sure  that  your  fuel 
supply  will  be  suffi- 
cient to  carry  you  to 
the  next  service  sta- 
tion, with  an  ample 
margin  to  spare. 

There  are  two 
kinds  of  service  for 
which  portable  sets 
are  designed  and 
your  B  batteries 
should  be  selected 
with  these  in  mind. 
First,  there  is  the 
pack  set,  which  can 
be  carried  on  a  hike, 
like  other  portable 
camp  equipment; 
and  second,  there  is 
the  self-contained 
semi-portable,  for 
temporary  installa- 
tion during  vacation 
time,  in  camp  or 
bungalow. 

The  Pack  Set 

TN  THE  pack  set, 

J-   everything  must       Thu  layout  snows 
be  sacrificed  to  se-      liberally  in  equippi 
cure    light    weight. 


Economical  upkeep  and  long  service  with- 
out renewal  of  batteries  must  give  way  to 
the  utmost  portability.  For  this  reason, 
the  smallest  and  lightest  B  battery  ob- 
tainable must  be  used,  because  the  larger 
sizes  are  altogether  too  bulky  and  heavy 
to  be  carried  for  any  great  distance. 

To  meet  these  requirements,  B  battery 
manufacturers  have  placed  tiny  radio 
power  plants  on  the  market.  These  con- 
sist of  an  assemblage  of  very  small  cells, 
sealed  in  a  small  container.  They  repre- 
sent the  greatest  possible  amount  of 
electrical  energy  which  can  be  crowded 
into  so  small  a  space.      But  the  output  of 


the  various    sizes    of  "B"    batteries.     It    is    advisable   to    spend 
ng  a  portable  set  with  "B"  batteries,  for  a  stingy  investment  at  the 
start  usually  results  in  woe  later  on. 


any  B  battery,  in  milli-ampere  hours,  is 
proportional  to  the  quantity  of  active 
chemicals  within  each  cell.  Only  a  cer- 
tain amount  of  each  essential  chemical 
can  be  placed  in  a  given  space.  Conse- 
quently, the  size  of  the  battery  places 
definite  limitations  upon  the  output 
which  may  be  expeated  from  it.  The 
smaller  the  battery,  the  shorter  its  life 
and  its  current  output.  B  battery  costs, 
per  hour  of  operation,  increase  rapidly 
as  the  size  of  the  battery  becomes  smaller. 
Before  starting  on  your  trip  with  a 
portable  set,  be  certain  that  you  have  a 
B  battery  power  supply  which  will  last 
over  the  period  of 
your  trip.  Do  not 
expect  long  life  from 
tiny  batteries  called 
upon  to  deliver 
heavy  currents  for 
multi-tube  sets. 
The  smallest  B  bat- 
tery, shown  at  the 
left  of  the  illustra- 
tion on  this  page, 
has  all  the  capacity 
which  can  be  incor- 
porated in  a  battery 
of  that  size.  It  has 
a  volume  of  17.5 
cubic  inches. 

The  next  larger 
size,  at  the  center, 
has  a  cubic  content 
of  28.6  cubic  inches, 
or  63  %  larger.  The 
tall,  slim  battery  at 
the  right  is  50.3 
cubic  inches  or 
186%  larger  than 
the  smallest  battery. 
Obviously,  there  is 
considerable  advan- 
tage both  in  milli- 
ampere  hour  capaci- 
ty and  economy  in 


20 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Voltage 

of 
Tubes 

No. 

of 
Tubes 
in  Set 

Type 
of 

Tubes 
(see  foot-note) 

Total 
Rated 
Ampere 
Drain 

Storage  "A"  Battery 

Size 

Recommended 

Amp.    Hours 

at   1    Amp. 

Drain 

Days 
between 
Chargings 

5-Vdlt 
Tubes 

1 

UV-200 

1 

65 

22 

47 

16 

2 

UV-201A 

l-i 

47 

33 

2 

1  UV-200 
1  UV-201A 

IX 

80 

22 

65 

17 

3 

UV-201A 

% 

65 

29 

47 

22 

3 

1  UV-200 

2  UV-201A 

V/i 

95 

21 

65 

14 

4 

UV-201A 

1 

65 

22 

C-300  and  UV-200 
are  interchange- 
able 

C-301A,  DV-2  and 
UV-201A  are  in- 
terchangeable 

47 

16 

4 

1  UV-200 

3  UV-201A 

1:!4 

115 

22 

80 

15 

5 

UV-201A 

IS 

80 

22 

65 

17 

5 
6 

1  UV-200 

4  UV-201A 

2 

115 

19 

80 

13 

UV-201A 

1?2 

95 

21 

65 

14 

8 

UV-201A 

2 

125 

21 

95 

15 

For  sets  using  cur- 
rent at  a  rate  higher 
than  2  amperes. 

2'i 

140 

22 

95 

13 

2K 

140 

19 

125 

16 

For  combinations  of  tu 
having  voltage  and  ct 

NOTE:     If  you  use  a  : 
rated  current  drain  ol 

)es  not  listed:     Use  the  same 
irrent  requirements  similar  to 
oud  speaker  operated  from  yo 
your  tubes  and  then  select  a  1 

Dattery  con- 
he  tubes  y< 
ur  "A"  Bat 
attery  givi 

binations  recommended  for  tubes 
m  have. 

tery.  add   H  ampere  to  the  total 
lg  this  total  current  consumption. 

This  chart,   recently  prepared  by  storage  battery  experts,   should  come  in    handy  for 

Jans  whose  knowledge  of  "A"  battery  characteristics  is  limited.      Cut  it  out  and  tack 

it  up  near  your  radio  set. 


buying  the  largest  possible  battery  which 
you  can  carry  with  you. 

A  pack  set,  intended  for  several  weeks' 
use  during  vacation  time,  will  give  more 
satisfactory  service  if  large  batteries  are 
used  outside  the  set,  while  it  is  used  at  its 
semi-permanent  location.  When  design- 
ing your  portable,  therefore,  equip  it  with 
flexible  B  battery  leads  so  that,  whenever 
possible,  you  can  use  larger  batteries  and 
so  that  you  may  limit  the  service  on  the 
small  batteries  to  those  occasions  when 
convenience  in  portability  compels  their 
use.  For  instance,  if  you  plan  to  take 
your  set  with  you  on  an  all-day  picnic, 
use  the  small  portable  batteries;  but  when 
you  get  back  to  the  permanent  camp  at 
the  shore  of  the  lake,  substitute  the  larger 
batteries  for  the  smaller  ones.  Your  two 
sets  of  batteries  may  then  last  you  all 
through  the  summer  season. 

The  Semi-Portable  Set 

7 1 1HE  semi-portable  set  can  give  all  of 
-*-  the  satisfaction  of  the  permanent 
installation,  so  far  as  battery  upkeep  is 
concerned.  Thousands  of  motor  campers 
take  good  radio  sets  with  them  because 
they  provide  the  finest  kind  of  entertain- 
ment after  the  day's  drive.  Even  if  the 
battery  compartments  in  the  set  do  not 


provide  sufficient  space  for  larger  bat- 
teries, leave  the  diminutive  batteries 
home,  and  make  space  in  your  car  for 
large  or  even  extra  large  B  batteries. 
If  you  have  room  for  a  radio  set,  you  have 
room  for  the  right  kind  of  batteries  to  go 
with  it.  Nothing  takes  quite  so  much 
space  as  a  radio  set  which  is  useless 
because  its  tiny  inadequate  B  batteries 
have  given  out. 

The  realization  that  an  adequately 
powered  set  is  the  only  kind  which  gives 
satisfaction  is  gradually  becoming  general. 
Nevertheless,  many  sets  on  the  market, 
including  some  intended  for  permanent 
installation,  are  equipped  with  compart- 
ments for  small  B  batteries,  encouraging 
inadequate  sources  of  power  supply. 

On  any  loud  speaker  set,  the  audio- 
frequency amplifier  can  be  made  very 
economical  in  its  current  requirements 
through  the  use  of  a  C  battery.  A  4J^ 
volt  negative  bias  on  the  grids  of  the 
audio-frequency  amplifiertubesfrequently 
reduces  their  current  drain  by  one-half 
or  two-thirds.  Consequently,  the  little 
C  battery  is  well  worth  its  weight,  even 
in  a  pack  set.  The  current  drain  to 
which  the  C  battery  is  subjected  is  so 
small  that  its  serviceability  is  limited 
only  by  its  shelf  life. 


The  illustration  shows  five  sizes  of 
B  batteries  in  such  a  manner  that  you  will 
be  able  to  identify  them  when  you  pur- 
chase B  batteries  for  your  portable  sets. 

The  smaller  sizes,  shown  at  the  front  of 
the  illustration,  should  be  used  only  when 
portability  requires  their  selection.  Their 
output  in  milli-ampere  hours  increases 
more  than  in  proportion  to  their  increase 
in  size.  Considering  that  the  largest  of 
these  portable  units — the  tall  battery 
at  the  right — has  less  than  25%  of  the 
electrical  capacity  of  the  large  battery 
shown  at  the  left  in  the  back,  the  greater 
lasting  qualities  of  the  larger  batteries 
become  obvious. 

The  large  size,  back  of  the  small  bat- 
teries at  the  left,  has  considerably  greater 
lasting  quality  than  the  next  preceding 
size.  It  is  the  middle  ground  between 
the  utmost  economy,  as  embodied  in  the 
extra  large  size,  and  the  uneconomical 
smaller  sizes.  There  are  several  makes 
of  semi-portable  sets  equipped  with 
battery  compartments  which  will  house 
these  large  batteries. 

On  the  other  hand,  if  it  is  possible  to 
employ  the  heavy  duty  battery  for  a 
three  or  five  tube  set,  as  illustrated  at  the 
right,  you  attain  the  greatest  econ- 
omy possible  in  radio  receiving  power 
supply.  These  batteries  will  last  much 
longer  than  the  smaller  sizes  and  they 
represent  the  best  buy  in  radio  power. 

Selecting  Strong  Batteries 

WHEN  selecting  a  storage  battery, 
every  owner  of  a  receiving  set 
desires  one  of  sufficient  capacity  to  make 
frequent  recharging  unnecessary,  yet 
small  enough  to  reduce  the  first  cost  to  a 
minimum.  Has  ideas  as  to  just  what  to 
specify,  in  order  to  obtain  this  highly 
desirable  combination,  may  be  somewhat 
hazy,  but  he  is  never  in  doubt  as  to  the 
result  he  seeks. 

Various  types  of  storage  battery  selec- 
tion charts  have  been  developed  in  the 
past,  which  were  intended  to  assist  the 
owner  of  a  receiving  set  in  making  a 
proper  selection.  Lately  a  chart  has  been 
developed  which  takes  into  consideration 
number,  type  and  combinations  of  tubes 
in  a  way  that  makes  selection  of  a  satis- 
factory battery  a  simple  matter. 

Voltage  of  tubes,  number  of  tubes, 
type  of  tubes,  rated  ampere  drain  and  re- 
charging interval  are  treated  in  the  chart 
in  such  a  way  that  the  receiving  set  owner 
has  a  choice  of  two  recharging  periods. 
For  instance,  for  a  set  using  one  UV-200 
and  three  UV-201A  tubes,  with  a  rated 
ampere  drain  of  1%,  and  "A"  battery  of 
115  amperes  (at  one  ampere  drain)  will 
give  22  days  of  service  without  recharging 
when  used  for  an  average  of  three  hours 
daily;  while  with  the  same  tube  combina- 
tion, a  battery  of  80  amperes  will  have  a 
recharging  interval  of  15  days.  Similarly, 
for  a  set  having  three  UV-201A  tubes  at 
%  ampere  drain,  a  battery  of  65  amperes 
insures  29  days'  service  while  the  smaller 
47  ampere  battery  gives  22  days'  service 
between  rechargings. 

By  calling  attention  to  the  types  of 
tubes  that  are  interchangeable,  it  will  be 
noted  that  the  accompaniyng  chart  gives 
practically  every  combination  of  5-volt 
tubes  in  general  use. 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


21 


A  Simplified  Portable  Super 


Here  is 

An  Outfit 

Whose  Cost 

Can  Be 

Kept  Well 
Below 

$13°  by 
the  Careful 
Home- 
Builder 


By  A.  J.  HAYNES 


The  set  described  by  Mr. 
Hayxies,  wired  and  ready 
to   go  into  the  cabinet. 


A  Popular  Receiver  That  Will  Give  Dependable 
Loud  Speaker  Results  in  Summer  Up  to  i  ,000  Miles 


FOR  the  past  three  years,  portable 
radio  sets  have  been  built  in  great 
profusion — in  Winter  conversations. 
When-  the  good  old  Summer  time  rolls 
around,  however,  rarely  does  a  radio 
set  accompany  Dad  in  his  jaunt  to  the 
Maine  woods  or  the  family  on  their 
annual  flivver  trip. 

This  lack  of  enthusiasm  in  the  past 
can  be  attributed  to  a  number  of  real 
reasons.  There  were  only  two  or  three 
broadcasting  stations  with  sufficient 
power  to  make  reception  pleasant  through 
static  disturbances  a  year  ago,  many 
portable  sets  were  "portable"  only  be- 
cause the  case  was  leather,  and  sometimes 
the  batteries  were  enclosed,  and  finally, 
the  cost  of  a  good  portable  receiver  was 
almost  prohibitive  for  the  average 
family. 

This  year  these  faults  have  been  rem- 
edied to  a  great  extent.  Stations  have 
increased  their  power  until  the  "static 
level"  has  been  pushed  some  hundreds 
of  miles  into  the  sticks.  There  are  now 
a  number  of  factory  built  portables 
which  can  be  classed  as  real  sets,  and 
what  is  more  important  to  most  of  us, 
the  cost  of  both  parts  and  accessories 
has  moved  downward  in  a  very  satis- 
factory   manner   during   the   last   year. 

The    design    of   the    set    shown    in    this 


article  has  been  thought  out  with  com- 
plete portability,  low  cost  and  good  per- 
formance as  the  primary  considerations. 
The  set  is  completely  self-contained. 
Although  the  loop  is  built  in  the  case 
cover,  it  will  be  found  as  efficient  as  the 
ordinary  loop  of  approximately  the  same 
dimensions.  The  cost  of  the  outfit  can 
be  kept  below  $130.00  for  the  complete 
units  and  this  price  includes  all  the  neces- 
sary tubes  and  batteries.  Even  this 
comparatively  low  price  can  be  cut  con- 
siderably by  judicious  shopping. 

Same  Constants 

TF  YOU  substitute  parts  other  than 
-*-  those  shown  in  the  material  list,  be 
sure  that  the  new  parts  have  constants 
exactly  similar  with  those  specified. 

The  circuit  employed  is  a  conven- 
tional "regenerative  loop"  affair.  The 
only  change  which  you  might  notice  is 
the  fact  that  the  pickup  coil  is  placed  in 
the  filament  lead  instead  of  in  the  grid 
lead  of  the  first  detector  tube.  This 
was  done  to  reduce  body  capacity  effects, 
which  are  often  severe  in  supers  using  a 
grid  pickup  with  regeneration. 

The  battery  supply  indicated  is  wholly 
adequate  for  the  drain  put  on  it.  Our 
test  set  ran  almost  continually  for  two 
weeks   while   we   were    making   tests   and 


the  batteries  still  have  lots  of  pep. 
The  "What  will  it  do?"  club  is  prob- 
ably becoming  quite  anxious  by  now, 
and  it  is  fair  that  they  be  answered. 
First,  claims  of  the  "coast-to-coast-on- 
the-loud-speaker-in-daylight"  type  are 
ruled  out.  The  set  will  give  dependable 
loud  speaker  results  in  the  Summer  time 
on  stations  up  to  a  distance  of  1000 
miles.  This  means  results  which  you 
can  enjoy  and,  if  you  are  listening  to 
music,  dance  to  it  without  having  to 
imagine  half  of  the  tune.  On  nights 
that  are  favorable  to  reception,  you 
can  make  a  very  comfortable  and 
thorough  tour  of  the  country  via  the 
loud  speaker. 

Most  of  the  tests  run  on  this  set  were 
made  in  Chicago,  which  is  notorious 
for  the  difficult  receiving  conditions 
caused  by  the  numerous  and  powerful 
stations  there,  and  the  results  were 
highly  satisfactory.  The  set  was  tried 
in  the  North,  West  and  South  sections 
of  the  city — each  with  its  own  particular 
set  of  problems,  and  in  no  test  was  the 
set  unable  to  pull  in  fewer  than  fifteen 
out-of-town-stations.  These  tests  were 
all  made  while  the  local  stations  were 
broadcasting. 

You  can  have  the  carrying  case  con- 
structed  by   a    local    firm   or   a    suitable 


4 

-      -0-  Q- 


The  socket  strip  for  the  simplified  portable  super-heterodyne,  showing  one  filament  lead  and  method  of  binding  lugs  for  other  filament  lead. 


22 


RADIO  AGE  for  July,  1925 


case  may  be  purchased  from  one  of  a 
number  of  firms  advertising  them.  Ow- 
ing to  the  chance  for  confusion,  it  is  best 
to  cut  the  leads  only  as  needed  and  to 
mark  the  drawing  as  they  are  used.  In 
this  way  a  double  check  is  kept  on  the 
work  as  you  go  along. 

Assembling  and  Wiring  the  Set 

If  the  instructions  given  are  followed 
carefully,  particularly  the  order  in  which 
the  leads  are  connected,  the  average 
fan  should  be  able  to  complete  the  wiring 
of  the  set  in  three  hours  or  less.  The 
time  required  to  complete  the  balance 
of  the  work  depends  on  the  cabinet. 
If  you  have  purchased  one  ready-made, 
the  set  should  be  operating  about  four 
hours  after  you  start  work  on  it. 

The    only   two    leads    which    must    be 
soldered  in  the  set  itself  run  to  the  jacks 
and,  owing  to  their  posi- 
tion,  are  easily  attached. 


Material  List 

1  5"xl6  K"x3/l6"  Bakelite  Panel 
1  l;54"xlO  K"s3/16"  Bakelite  Strip 

1  7"xl6  >2"x3/l6"  Veneer  Baseboard 

2  .0005  mfd.  Variable  Condensers 
1  Set  I.  F.  Transformers 

1  Oscillator  Coupler 

1  3  Plate  Condenser  &  Knob 
S  TJV199  Sockets 

2  Audio  Transformers 

1  400  Ohm  Potentiometer 
1  Filament  Switch 

1  Turnit  Condenser 

2  .006  mfd.  Condensers 
1  .005  mfd.  Condenser 

1  .002  mfd.  Condenser 

2  .00025G  mfd.  Condene- 


1  3   Megohm   Grid   Leak 
1  5   Megohm  Grid   Leak 

1  10      Ohm      Type      301 
Rheostat, 

50  ft.  Hookup  Wire 
3  ft.  5-conductor  Battery  Cable 
29  6-32x5/16"  F.  H.  Brass  Machine  ScrewB 
12  6-32xH"  F.  H.  Brass  Machine  Screws 
7  6-32x1  H"  F-  H-  Brasj  Machine  Screws 
40  6-32  Brass  Nuts,  %"  Across  Fhrts 
12  6-32  Brass  Nuts,  H"  Across  Flats 

2  Brackets  No.  1509 

2  Brackets  No.  1506 
S  Brackets  No.  1505 

3  Brackets  No.  1476 
9  Doz.  Small  Lugs 

4  Lengths  Rosin  Core  Solder 

18  Brass  Washers  for  6-32  Machine  Screws 
12  $&"  Brass  Wood  Screws 

5  Rubber  Binding  Posts 

4  Bakelite  Loop  Support  Strips 
100  ft.  Stranded  Loop  Wire 
1  Portable  Cabinet 
1  Loud  Speaker 

Bakelite  was  chosen  for  the  first  two 
panels  because  of  its  mechanical  strength. 
Veneer  was  chosen  for  the  baseboard 
because  of  its  cheapness  and  light  weight. 
If,,  however,  you  wish  to  use  hard  rubber 
or  bakelite  at  this  point,  there  are  no 
reasons  why  you  shouldn't. 


Here  is  the 
completed  set 
ready  for  ac- 
tion, with  a 
new  type  of 
loud-speaker. 
This  is  truly  a 
portable  out- 
fit, and  tests 
in  the  crowd- 
e  d  Chicago 
area  showed 
it  cuts  thru 
locals  up  to 
1,000  miles 
on  the  speak  - 
er.  That's 
good  for  sum- 
mer, isn't  it? 
Note  the  loop 
wound  in  the 
cover. 


When  the  panels  have  been  drilled 
and  countersunk,  mount  the  proper  parts 
on  the  panel  and  baseboard.  Do  not 
mount  the  oscillator  coupler  on  the  base- 
board at  this  time,  as  there  is  some  pre- 
liminary wiring  on  it  which  can  be  done 
more  easily  if  it  is  not  mounted.  6-32x 
Jfs"  machine  screws  are  used  to  secure 
the  instruments  to  the  board. 

The  Socket  Strip 

T^HE  assembly  and  partial  wiring  of 
-*-  the  socket  strip  should  now  be  under- 
taken. Where  a  bolt  is  used  to  attach 
only  the  socket  to  the  strip,  use  6-32x^i" 
machine  screws.  Where  a  bolt  attaches 
both  a  socket  and  a  condenser  to  the 
strip,  use  6-32x1  %"  machine  screws 
and  cut  off  the  extra  length.     Be  sure  to 

SCHEMAmC  D\KG^KM 


The  Magazine  of  the  Hour 

place  a  lug  under  each  nut 
which  locks  both  a  socket 
and  condenser  in  place. 
This  is  done  at  points  A10, 
All,  and  A12. 

Before  attaching  the 
.O0O25G  condenser  in  place, 
put  a  6-32x^m"  machine 
screw  through  the  conden- 
ser at  H5.  Lead  No.  35  is 
now  cut  to  length  and  at- 
tached under  the  nut  at  L 
and  the  other  end  secured 
at  LI,  the  Grid  of  the  first 
detector  tube. 

Lead  No.  1  is  attached  at 
the  end  of  the  5  "  section  to 
the  first  grid  condenser  at 
H5. 

Leads  are  now  partially 
completed  to  each  of  the 
by-pass  condensers  on  the 
socket  strip.  Lead  No.  25 
is  soldered  to  the  .606  con- 
denser at  G4.  Solder  one 
end  of  lead  No.  22  to  the 
other  .006  condenser  at  D6. 
One  end  of  lead  No.  26  is 
soldered  to  the  .005  con- 
denser at  C4.  At  L2  of  the 
.002  condenser  solder  lead 
No.  23  and  attach  the  other 
end  to  the  plate  of  the 
*  second  detector  tube,  L. 
The  lugs  which  were  left  at  points  A10, 
All  and  A12  are  now  turned  until  they 
pass  under  the  nuts  at  A6,  A8  and  A13. 
The  negative  filament  lead  is  later 
attached  to  these  points  and  the  lugs  form 
a  very  convenient  method  of  making 
short  leads. 

Leads  8  and  9  are  now  cut  from  two 
pieces  of  round  bus  bar  and  form  the  two 
filament  bus  lines  on  the  socket  strip. 
Place  a  lug  under  each  of  the  filament 
terminals  on  the  sockets  projecting  at 
right  angles  to  the  socket  strip,  bend 
the  tips  to  right  angles,  insert  and  solder 
the  bus  bar  and  finally  bend  the  com- 
pleted leads  as  close  to  the  sockets  as 
possible.  No  identifying  letters  have 
been  placed  on  the  diagram  to  show  the 
position  of  these  leads  but  as  the  sockets 
are  marked,  you  should  have  no  difficulty 
in  doing  the  job  correctly.  These  last 
operations  complete  for  a  moment  the 
work  on  the  socket  strip  and  we  shall 
turn  to  the  wiring  of  the  oscillator 
coupler. 


)  OHW  POtEHTlOWWKfcR. 


The  schematic  wiring  diagram  of  Mr.  Haynes'  receiver. 


By  following  this  layout  the  beginner  should  have  no  trouble  in  building 
the  portable  super. 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


23 


y 


6- 


EjjffljU 

©-^  ©r"   @p]  -gr®  @-^-€r[ 

i.  T     T  /fti 


&JL 


en 


The  oscillator  coupler  consists  of  three 
separate  windings:  the  pickup  coil,  the 
grid  coil  and  the  plate  coil.  In  referring 
to  the  "inside"  or  "outside"  connections 
to  a  section  of  the  coil,  the  tap  nearest 
the    center    or   furthest    from   the    center 


is  meant  respectively.  Attach  one  end 
of  lead  No.  32  to  the  inside  terminal  of 
the  pickup  section  at  A7.  Lead  No.  3 
is  attached  to  the  outside  terminal  at 
H3.  Lead  No.  19  is  attached  at  J  to  the 
inside     terminal     of     the     plate     section. 


LENGTHS  Of  LEKD5  \VA  5E.1 


Attach  the  lug  at  the  end  of  the  10" 
section  of  lead  No.  5  to  the  outside  ter- 
minal of  the  plate  section  at  CI.  Fasten 
lead  11  with  the  tap  at  the  end  of  the 
10  J^"  section  to  the  inside  terminal  of 
the  grid  coil  at  El.     The  lug  at  the  end 


f^ 


—I 


t^ 


B=© 


-.*£ 


—4 


of  the  7}4"  section  of  lead  No.  13  to 
the  outside  terminal  of  the  grid  coil  at 
K.  This  completes  for  the  moment,  the 
wiring  on  the  oscillator  coupler. 

The  battery  cable  should  be  prepared 
for  use  by  cutting  away  the  covering  for 
a  distance  of  14".  Whipping  the  cover- 
ing at  this  point  will  prevent  fraying  of 
the  covering  from  taking  place.  Use 
fairly  heavy  thread  for  this  purpose. 
Measure  the  length  of  the  battery  leads 
from  the  point  that  the  covering  is  cut. 
The  C  battery  negative  is  lead  No.  10. 
Filament  negative,  B  battery  negative 
is  lead  No.  14.  B  battery  positive  de- 
tector is  lead  No.  39.  Lead  No.  21  is  the 
filament  positive.  B  Battery  positive 
amplifier  is  lead  No.  20. 

Lettering  used  to  designate  battery 
circuits  are  based  on   the  following  list: 

A  minus     B  minus ..Letter   A 

A  plus Letter   B 

B  plus  detector Letter   C 

B  plus  amplifier Letter  D 

C  minus Letter   E 

(Turn  to  page  55) 


2 1  RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Tricks 

of 

Summer 

Radio 


^J^ 


Suppose  a  receiving  station 
in  Chicago  is  receiving  both 
from  New  York  and  Los 
Angeles.  A  patch  of  radio 
fog  might  appear  between 
New  York  and  Chicago  and 
weaken  the  New  York  sig- 
nals, while  the  signals  from 
Los  Angeles  remain  un- 
changed. The  map  shows 
how  we  sometimes  receive 
signals  from  the  West  bet- 
ter than  those  from  the 
less  distant  East. 


T7VERY0NE  who  has  a  radio  receiving 
■*-*  set  has  'met  the  atmospheric  nuisance 
called  "static."  It  comes  in,  especially 
during  the  warm  months,  and  interferes 
with  clear  reception.  A  particularly 
pleasing  musical  number  may  be  on,  but 
that  makes  no  difference  to  Old  Man 
Static. 

So  many  inquiries  have  been  received 
at  the  General  Electric  station,  WC  Y,  at 
Schenectady,  that  A.  F.  Van  Dyck,  a  radio 
engineer,  has  prepared  the  following 
paper,  explaining  some  things  that  are 
known  about  static  and  what  is  being 
done  to  get  rid  of  it.  Mr.  Van  Dyck's 
explanation  follows: 

IN  THE  letters  which  WGY  has 
received  from  listeners,  certain  ques- 
tions have  been  asked  by  many 
different  inquirers.  Some  of  these 
questions  involve  radio  phenomena  which 
are  not  completely  understood  by  scien- 
tists today,  and  the  answers  and  explana- 
tions which  we  shall  give  should  be  under- 
stood to  be  the  ones  which  are  believed 
to  be  nearest  the  truth,  although  they 
are  not  subject  to  rigid  proof. 

First,  let  us  consider  what  radio 
transmission  is.  We  know  that  a  radio 
sending  station  sends  out  from  its  an- 
tenna in  all  directions,  a  disturbance  of 
electric  forces.  We  cannot  see  or  hear 
or  otherwise  observe  with  our  senses  just 
how  this  disturbance  behaves,  as  we  can 
with  light  waves  and  sound  waves. 
We  consider  it  quite  natural  that  a  stone 
wall  stops  the  light  beam  from  a  search- 
light, or  that  a  bugle  call  can  be  heard 
much  farther  over  water  than  through  a 
forest,  or  that  under  certain  air  condi- 
tions on  a  desert,  the  mirage  phenomenon 
is  observed;  and  to  know  what  to  expect 
in    radio,    we    need    only    to    remember 


that  some  things  in  space  will  stop,  or 
reflect,  or  perhaps  absorb  the  travelling 
radio  waves,  just  as  some  other  things  in 
space  stop  or  absorb  or  reflect  light 
waves,  or  sound  waves.  We  must  not 
expect  radio  waves  to  travel  out  from  a 
transmitting  station,  over  some  enor- 
mous distance  to  a  receiving  station, 
without  encountering  some  obstacles 
somewhere  in  its  path. 

How  Radio  Pierces  Walls 

QUBSTANCES  which  are  obstruc- 
^  tions  to  light  or  sound  waves-are  not 
necessarily  such  to  radio  waves.  For 
example,  we  know  that  radio  waves  pass 
through  the  walls  of  a  house  with  only 
slight  loss.  But  there  is  some  substance 
in  the  space  around  the  earth  which 
does  have  effect  upon  radio  waves.  This 
substance  is  not  uniformly  distributed 
through  space,  but  is  present  here  and 
there,  and  is  continually  changing  loca- 
tion and  magnitude,  and  consequently 
has  very  erratic  effects  on  the  passage  of 
radio  waves. 

The  condition  is  quite  similar  to  the 
use  of  a  searchlight  in  a  fog,  which  might 
be  varying  rapidly  in  density  or  location, 
or  both.  This  radio  fog  is  commonly 
supposed  to  be  made  of  ionized  air; 
that  is,  air  which  by  some  influence  has 
become  a  partial  conductor  of  electricity. 
Of  course,  this  radio  fog  never  stands 
still  and  is  changing  from  moment  to 
moment  under  the  influence  of  the  com- 
plicated conditions  of  our  atmosphere, 
and  so  the  radio  wave  passing  through 
space  surely  has  an  adventurous  journey 
because  it  meets  electrically  charged 
clouds,  patches  of  ionized  air,  and  per- 
haps other  obstacles  of  which  we  know 
nothing. 

It  is  a  fact  often  observed   that   it   is 


A  Realistic 

Analysis  by 

A.F.  VAN  DYCK 


possible  to  work  radio  communication 
over  much  greater  distances  at  night  than 
in  the  daytime.  This  may  be  explained 
by  the  effect  of  the  sun  upon  the  air, 
which  causes  ionization  of  it,  and  is  most 
active  in  the  daytime  and  practically 
absent  at  night.  The  sun  seems  to  be 
responsible  without  question,  in  view  of 
the  fact  that  very  erratic  results  in  long 
distance  reception  are  always  noticed 
at  sunrise  and  sunset. 

Wave  Power  Varies 

WITH  the  preceding  statements  in 
mind,  it  should  be  clear  that  when 
one  is  receiving  over  long  distances — 
several  hundreds  of  miles — it  is  natural 
for  the  waves  to  come  through  strong  at 
one  moment,  and  to  fade  away  consider- 
ably the  next  moment,  as  some  obstacle 
to  radio  waves  comes  between  the  trans- 
mitter and  receiver.  This  explains,  too, 
why  one  transmitting  station,  of  two  or 
more  which  are  being  heard,  may  get 
weaker,  while  the  others  do  not.  For 
example,  suppose  a  receiving  station  in 
Chicago  is  receiving  from  New  York 
and  also_  from  Los  Angeles.  A  patch  of 
radio  fog  might  appear  between  Chicago 
and  New  York  and  weaken  the  New 
York  signals,  while  the  signals  from 
Los  Angeles  remained  unchanged.  When- 
ever in  reception  over  a  considerable 
distance,  one  observes  a  variation  in  the 
intensity  of  the  signals,  it  is  most  likely 
due  to  so-called  "fading,"  caused  by 
some  obstruction  to  the  traveling  waves 
somewhere  between  the  two  stations, 
and  not  to  any  fault  of  the  transmitting 
station  itself.  These  effects  are  much 
more  frequent  in  the  Summer  than  in  the 
Winter,  presumably  because  of  the  great- 
er influence  of  the  sun  on  the  earth  and 
(Turn  to  page  60) 


RADIO  AGE  for  July,  1925 


What  the  Broadcasters  are  Doing  25 


Gloria  Confesses 


Gloria  Swanson,  who  since 
her  marriage  to  a  dashing 
Frenchman  is  Marchioness 
Something-or-Other,  made  her 
first  broadcasting  appearance 
under  her  new  name  from 
WGN,  located  on  the  Drake 
Hotel,  Chicago.  Seated  before 
the  "Mike,"  she  answered  sev- 
eral exceedingly  personal  ques- 
tions put  to  her  by  Announcer 
Quin  A.  Ryan  of  WGN.  The 
questions,  by  the  way,  had 
been  sent  in  by  inquisitive 
listeners  who  had  been  notified 
of  the  famous  "Radio  Inter- 
view" with  Gloria  as  the  Inter- 
viewee, who  seemed  willing  to 
tell  all  her  deep  secrets  for  her 
radio  and  movie  admirers. 


(Photo  Copyright  by  Drakfi  Studio.  Chicago) 


26  RADIO  AGE  for  July,  1925 


What  the  Broadcasters  are  Doing 


Wkat  tke 

Broadcasters 

are  Doing 


Portable  "Pick-up"   Station 
for   KDKA 

'  1 ,0  TAKE  care  of  the  ever-increasing 
-*-  "pick-up"  situation  that  has  con- 
fronted Westinghouse  station  KDKA, 
at  E.  Pittsburgh,  the  Westinghouse 
engineering  department  detailed  Engi- 
neer Carrol  J.  Burnside  to  construct  a 
portable  short  wave  sending  station, 
to  permit  the  immediate  and  practical 
broadcasting  of  various  interesting  and 
important  events,  as  they  take  place  in 
their  vicinity,  despite  the  fact  that 
location  may  not  permit  telephone  wire 
connection    with    KDKA. 

A  one-ton  truck  ,  chassis  was  pur- 
chased and  suitable  house-body  built, 
wherein  the  pick-up  apparatus  was  con- 
structed. The  requirements  of  this 
transmitter  were  that  it  be  absolutely 
dependable  at  all  times,  in  any  loca- 
tion, and  make  use  of  a  low  wavelength, 
which  is  free  from  interference.  The 
equipment  must  be  compact  and  its 
personnel  small  and  upkeep  low,  to 
justify  its  use.  The  body  of  the  truck 
is  5  ft.  wide  by  9  ft.  long  and  is  6  ft. 
high  inside,  solidly  built  to  withstand 
the  jar  of  movement  of  the  truck  in 
motion.  All  equipment  is  cushioned  to 
minimize    the   jarring    of   apparatus. 

The  transmitter  is  a  quarter-KW  §et, 
using  110V  from  lighting  circuit  where 
program  is  being  broadcast,  and  a  power 
transformer  in  the  truck  is  used  to  step 
up  to  the  high  voltage  required  to  oper- 
ate the  set.  Power  at  this  high  voltage 
is  passed  through  a  vacuum  tube  rectifier 
using  two  quarter  KW  air-cooled  recti- 
fier tubes,  which  gives  single  phase  full 
wave  rectification.  The  output  of  the 
tubes  is  passed  through  a  brute  force 
filter  of  choke  coils  and  condensers, 
which  delivers  2000  volts  DC  power  to 
the  transmitter,  which  makes  use  of  the 
standard  Hartley  oscillator  circuit  with 
Heising     modulation. 

The  equipment  used  in  this  portable 
set  is  capable  of  wavelengths  varying 
from  20  to  100  meters,  although  the 
set  will  ordinarily  be  operated  on  about 
53  meters — KDKA  to  pick  up  its  broad- 
cast and  rebroadcast  on  their  standard 
wavelength   of   309    meters. 

Because  of  a  likelihood  of  broad- 
casting from  some  downtown  section 
of  the  city,  where  it  would  not  be  prac- 
tical to  operate  a  regular  antenna,  a 
vertical  oscillator  type  is  used.  A 
copper  pole  of  three  sections,  of  the 
telescoping  type  was  constructed,  which 
is  folded  and  stored  in  the  truck  when 
not  in  use. 


Iris  Virginia  Gruber  has  the  distinction  of  broad- 
casting more  than  any  artist  in  Philadelphia  and 
is  the  winner  of  the  Radio  Cup  presented  for 
singing  the  greatest  number  of  times  during  the 
concert    season    from    January    1st    to    May    1st. 


"Ford   and    Glenn"    to 
Tour  U.  S. 

FORD  RUSH  and  Glenn  Rowell, 
the  "Lullaby  Boys,"  whose  songs 
and  bed-time  stories  during  "Lullaby 
Hour"  and  "Ford  and  Glenn  Time" 
over  WLS,  the  Sears-Roebuck  station, 
Chicago,  have  endeared  them  to  the 
hearts  of  kiddies  and  their  parents 
throughout  the  nation,  will  start  on  a 
transcontinental  tour  of  the  United 
States  June  2.  The  WLS  favorites  will 
broadcast  their  most  popular  features 
over  nineteen  of  the  principal  radio 
stations   clear   to   the    Pacific    Coast. 

The  journey  from  station  to  station 
will  be  made  in  their  new  sedans,  in 
which  they  will  carry  complete  camping 
outfits.  In  many  of  the  places  they 
will  live  out  in  the  open  with  their 
families,     who     will     accompany     them. 


Above  is  "Si"  Berg,  nationally  known  ukelele 
artist  and  songster,  who  has  appeared  all  over 
the  country  before  prominent  microphones.  He  is 
now  appearing  consistently  from  WHT  and  KYW, 
Chicago,  having  contributed  recently  to  the 
success  of  many  RADIO  AGE  programs  from 
the    latter    station. 


McNamee   of  WEAF  Chosen 
Best  Announcer 

(GRAHAM  McNAMEE  of  WEAF 
*~*  was  selected  as  the  best  all-round 
local  announcer  by  the  Radio  Voice 
Technique  Committee  of  New  York 
University  at  a  meeting  held  recently, 
according  to  announcement  made  by 
the  committee.  McNamee  nosed  out 
Brockenshire  of  WJZ  by  the  small 
margin  of  four-tenths  of  a  point,  the 
scores  being  87.3  for  McNamee  and 
86.9  for   Brockenshire. 

This  committee  meeting  terminated 
the  series  of  three  which  were  held 
during  the  past  four  months  under  the 
direction  of  R.  C.  Bordon  and  A.  C. 
Busse,  voice  experts  of  New  York  Uni- 
versity, to  determine  the  ideal  qualities 
to  be  looked  for  in  radio  announcers. 
The  aim  of  the  committee,  which  is 
composed  of  radio  editors,  .  dramatic 
critics  and  members  of  the  faculty 
of  New  York  University,  is  not  to 
standardize  the  voice  and  art  of  broad- 
casting, but  to  point  out  faults  to  be 
avoided  and  to  determine  what  the 
public    prefers    to  Lear. 

Special  phonograph  records  were  made 
by  Mr.  Borden  and  Mr.  Busse  of  repre- 
sentative announcers  from  the  following 
nine  New  York  stations: — WJZ,  WEAF, 
WGBS,  WHN,  WEBJ,  WOR,  WAHG, 
WMCA,  and  WBBR.  Each  announcer 
passed  upon  his  own  record  and  all 
those  entered  in  the  contest  had  been 
accepted  by  the  makers  as  fairly  repre- 
sentative of  their  work. 

Ten  men  out  of  the  number  considered 
were  chosen  as  the  best  local  announcers. 
In  addition  to  McNamee  and  Broken- 
shire  they  are  Barnett  of  WOR,  Reed 
of  WJZ,  Carlin  of  WEAF,  Squires  of 
WMCA,  Granland  of  WHN,  Haupt  of 
WEAF,  Cross  of  WJZ  and  Morgan  of 
WGBS. 

The  committee  rated  the  records 
upon  the  points  which  were  decided 
upon  at  earlier  meetings  as  those  most 
desirous  for  radio  announcing.  They 
are  as  follows:  (1)  Average  rate  of 
speaking — 175  words  a  minute.  (2) 
Pitch  of  voice — low  middle  range.  (3) 
Announcements  should  be  made  with 
variation  of  rate,  pitch  and  stress. 
(4)  Manner  of  announcer — formal  but 
friendly.  (5)  Distinctness  and  enun- 
ciation. 

A  summary  of  the  comments  made 
by  the  committee  during  the  course  of 
the  meeting  has  been  arranged  by  Mr. 
Borden  and  Mr.  Busse  for  public  dis- 
tribution. 


RADIO  AGE  for  July,  1925 


What  the  Broadcasters  are  Doing  27 


^THE  alluring 
■*  Miss  adorning 
the  perfume  bottle 
is  none  other  than 
Mile.  Rosario 
Duprez,  promi- 
nent New  York 
fashion  queen,  who 
is  telling  the  flap- 
pers ana  gay  ma- 
trons in  the  East 
how  to  achieve  per- 
sonality by  means 
of  perfume.  Need- 
less to  say,  she  has 
a  large  feminine 
(and  masculine) 
following,  both  for 
her  radio  as  well 
as  her  pulchri- 
tudinous  attain- 
ments. 


THE  Great  and 
the  Near  Great 
Appear  Before  the 
WGBS  "Mike"  in 
New  York  To  Be 
Interviewed  and 
Reveal  How  to 
Achieve  Success. 


A  WOMAN  has  brought  the  news- 
paper to  the  radio  world.  She  has 
woven  the  two  togteher  and  has 
brought  shortcomings  of  one  to  be  val- 
uable features  of  the  combination. 

She  is  Terese  Nagel,  the  "Interview" 
lady  of  WGBS,  the  Gimbel  Brothers 
store,  New  York  City.  A  newspaper 
woman  of  ten  years  experience,  Miss 
Nagel,  just  a  short  time  ago,  brought 
that  most  famous  of  newspaper  features, 
the  interview,  within  reach  and  audi- 
bility of  every  radio  fan. 

The  scheme  is  clever.  Nearly  every- 
one wants  to  become  as  nearly  acquainted 
as  possible  with  famous  people,  but  it 
seemed  a  difficult  matter  to  bring  the 
celebrities  to  the  public  through  radio. 
Those  who  could  sing  or  play  an  instru- 
ment, of  course,  were  immediately 
brought  on  the  air,  but  it  remained  for 
Miss  Nagel  to  bring  those  who  conquered 
art  in  its  more  inaudible  forms  before 
the  microphone  in  a  satisfactory  manner. 

She   Gets   the   Celebrities 

\LMOST  every  person  of  importance 
-^*-  in  New  York  and  visiting  the  city 
has  spoken  before  the  WGBS  micro- 
phone through  the  efforts  of  Miss  Nagel. 
She  takes  them  there,  and  then,  with  her 
newspaper  instinct  and  ability,  draws 
forth  their  thoughts,  their  hopes  and  am- 
bitions for  all  the  world  to  hear.  Fay 
King  has  called  Miss  Nagel  the  "news- 
paper woman  of  the  air." 

She  got  a  "scoop"  the  day  that  I 
visited  her  for  an  interview  on  her  work. 
When  I  approached  the  beautiful  studio 
on  the  seventh  floor  of  Gimbel  Brothers, 
having  passed  a  group  of  people  who  were 
standing  outside  of  the  glass-windowed 
studio,  I  found  that  Miss  Nagel  was  on 
the  radio. 

She  finished  her  interview  and  dashed 
for  the  telephone.     "A  scoop,"  she  said, 


and  I  waited  until  she  had  finished  her 
call. 

"I  just  did  a  good  piece  of  newspaper 
work,"  she  told  me.  "I  was  just  inter- 
viewing Mrs.  Anna  Norton,  who  was 
chairman  of  the  democratic  party  during 
their  national  convention,  and  found 
that  she  is  going  after  a  big  political  job 
here  in  New  York.  I  rather  think  that 
she  let  it  slip  unintentionally,  but  I 
found  out  that  she  will  run  for  the 
nomination  for  registrar  of  the  city. 
It  pays  $12,000  a  year.  I  just  finished 
speaking  to  the  city  editor  of  the  New 
York  American,  and 
he  has  congratulated 
me.  v 

"That  just  goes 
to  show,"  she  con- 
tinued, "that  the 
radio  has  unlimited 
possibilities.  Just  at 
present  knowledge 
of  who  will  run 
for  registrar  is  very 
important,  and  the 
fact  that  a  woman 
will  do  it  makes  the 
scoop  valuable." 

How  She   Does  It 

SHE  then  told  me 
about  her  job  of 
interviewing  celeb- 
rities, and  how,  by 
her  clever  questions, 
she  draws  informa- 
tion from  them 
which  they  proba- 
bly would  never  di- 
vulge in  another 
way. 

"I  have  inter- 
viewed hundreds]  of 
famous  people.  I 
can  tell  you  some  of 


MARY  M  ELI  SH,  famous  Broadway 
stage  star,  was  one  of  the  first  celeb- 
reties  to  be  interviewed  by  Miss  Nagel 
from  WGBS.  The  radio  audience  en- 
joyed her  demure  confessions  of  stage 
life,  but  they  would  have  enjoyed  them 
much  more  if  they  could  have  seen  the 
lady  in  question.     (M.  Kesslere  Photo.) 


Radio's 
"Interview 

Lady" 
Scoops  the 

World ! 

By  MILTON 

LIEBERMAN 


them.  There  was  Rube  Goldberg,  Miss 
Oliver  Herriman,  Jane  Cowl,  Tony 
Sarg,  Victor  Depew,  the  cartoonist, 
Willem  Van  Hoogstratten,  conductor  of 
the  New  York  philharmonic  orchestra, 
Fay  King,  several  actresses,  including 
Miss  Blanche  Yurka  and  Miss  Mary 
Mellish.  The  Hamilton  brothers,  Cosmo 
Hamilton  and  Hamilton  Gibbs,  were 
very  interesting.  There  .was  also  Coun- 
tess Caroli,  whose  husband  was  first 
president  of  the  Hungarian  Republic. 

"It  is  very  interesting,  and  I  think  I 
shall  bring  more  newspaper  features  to 
the  air.  I  plan  to 
start  a  radio  column 
I  and  become  the  first 
radio  columnist. 
The  public  will  be 
asked  for  a  name  for 
the  column  and  con- 
tributions like  those 
used  in  newspapers 
will  be  accepted." 

Rosario  Duprez 
is  another  favorite 
from  WGBS.  She 
is  the  "Perfume  and 
Personality"  lady 
who  believes  that 
perfume,  properly 
used,  will  enhance 
the  personality  of 
any  woman.  Miss 
Duprez,  unfortun- 
ately, cannot  be  seen 
on  the  radio.  Un- 
fortunate it  is,  for 
she  is  the  essence  of 
charm  and  person- 
ality. WGBS,  how- 
ever, has  many  other 
ambitions,  besides 
linking  newspaper 
work  and  perfume 
with  radio. 


28  RADIO  AGE  for  July,  1925 

A  Station 
Broadcast 


What  the  Broadcasters  are  Doing 

Where  They 
"Personality 


By  C.  Clyde 
Cook,  who 

Knows  His 
Hollywood 

as  Marconi 

Knows  His 
Radio 


Real  Joy 

Dispensers 

at  KHJ  Keep 

the  Home 

Fires 

Burning  in 

California 


I 


Three  of  KHJ's  scintillating  stars     are     shown     above,        in     their 
proper  atmospheric  setting.     From  left  to  right  they  are  "The  Sand- 
man," who  lulls  the  children  to  sleepy  land,  "Uncle  John"  Daggett, 
the  Good  Samaritan  of  KHJ,  and  on  his  knee,  the  little  Queen  Tilania, 
who  is  a  fairy  optimist  for  thousands  of  hard-working  Catifornians. 


WHEN  Signor  Marconi  invented 
the  Wireless  Telegraph,  little  did 
he  think  that  in  the  near  future 
this  same  great  invention  would  advance 
with  such  strides  that  Personality  should 
some  day  be  broadcast  to  the  inhabi- 
tants of  this  universe. 

Although  it  may  sound  like  another 
Hollywood  Press  Agent's  stunt,  this 
phenomenon  has  certainly  been  accom- 
plished at  station  KHJ,  The  Los  Angeles 
Times,  Los  Angeles,  California,  where 
none  other  than  John  S.  Daggett,  affec- 
tionately known  to  Radio  fans  as  Uncle 
John,  works  this  miracle  with  a  resonant 
voice  which,  according  to  motion  picture 
standards,  registers  "personality  plus." 
Personality,     some    great    philosopher 


has  epitomized,  is  that  intangible  and 
indescribable  force  which,  of  necessity, 
must  come  from  within.  Which,  re- 
duced to  understanding  English,  only 
means  that,  to  possess  Personality  in  a 
marked  degree,  one  must  radiate  that 
magnetic  force  or  power  from  a  most 
dynamic  source — the  heart!  And  that 
is  the  sole  reason  why  Uncle  John,  direc- 
torial wizard  of  KHJ,  has  such  a  won- 
derful personality — he  has  a  magnani- 
mous heart,  and  his  Radioland  converts 
are  becoming  legion. 

KHJ'S  "Father" 

r  I  ''HIS  famous  broadcasting  station 
-*-  owes  its  existence,  perhaps,  to  Uncle 
John's  genius,   for  it  was  he   who   dedi- 


cated KHJ  to  the  horde  of  inhabitants 
of  Radioland  on  April  13th,  1922.  Like 
Aladdin's  magic  lamp,  Uncle  John  has 
wrought  miracles  with  this  magnificent 
.broadcasting  station.  KHJ  has  bright- 
ened more  homes  of  sorrow,  brought  more 
harmony  and  joy  into  homes  of  discord, 
than  any  other  three  stations  combined. 
And  this  is  because  his  attitude  towards 
his  duties  as  an  announcer  has  been  that 
of  a  minister  of  humanity,  and  his  cheery 
voice  has  come  to  mean  as  much  in  the 
home  as  the  teachings  of  the  scripture. 
Bringing  to  this  position  of  announcer 
a  splendid  college  education  and  the 
invaluable  experiences  of  a  successful 
newspaper  man,  there  is  little  wonder 
that    Uncle    John's    name    has   virtually 


RADIO  AGE  for  July,  1925 


What  the  Broadcasters  are  Doing 


29 


G.  Allison  Phelps  is  known  as  the 
Radio  Philosopher  of  KHJ,  Los  An- 
geles. Usually  philosophy  is  either 
dry  or  preaching.  But  not  the  way 
"At"  tells  it.  He  makes  you  cry  for 
more. 


become    a     household    term    in     the 
Southwestern      United     States,     and 
wherever   the  powerful 
casting  station  can  be 
heard.    For  Uncle  John 
has  seen  fit  to  arrange 
programs  which 
appeal  to  every 
member  of  the 
family,    with    a 
view  to  entertain- 
ing and  enlighten- 
ing his   great    fol- 
lowing   of     Radio 
fans,  for  he  has  a 
penchant        for 
broadcasting     the 
best  talent  obtain- 
able anywhere. 

Thanks  to  KHJ 
and  its  progeni- 
tor, Uncle  John, 
concerts  of  the 
highest  type  can 
be  heard  in  one's 
home.  KHJ  is 
probably  the  only 
station  which  has 
on  its  staff  an 
accomplished   and 

famous  musician.  In  the  person  of 
Claire  Forbes  Crane,  Radio  Editor  of 
the  Times,  KHJ  boasts  a  pianist  who 
has  been  soloist  with  such  large  musical 
aggregations  as  the  Boston  Symphony 
Orchestra,  the  Los  Angeles  Philhar- 
monic Orchestra,  and  others.  With 
the  technique  acquired  as  associate 
artist  of  Madame  Melba,  Arthur  Hac- 
kett  and  other  renowned  artists,  she 
brings  to  Radioland  a  veritable  "Open 
Sesame"  to  shut-ins  with  musical  long- 
ings. Under  her  artistic  guidance  the 
musical  programs  of  KHJ  have  thrilled 
music  lovers  throughout  the  nation. 

His  Universal  Appeal 

T3UT  Uncle  John's  magical  Radio  wand 
J-'  is  not  confined  to  classical  music. 
His  musical  programs  are  so  arranged 
as  to  carry  the  universal  appeal,  running 
the  gamut  of  musical  emotions  in  the 
human  race.  Just  to  prove  how  broad 
a  scope  and  range  these  musical  enter- 
tainments cover,  permit  me  to  quote 
verbatim  the  mutterings  of  an  alkili- 
coated  miner  from  the  great  open  spaces: 

"Out  on  the  Mojave  Desert  we  gets 
mighty  lonesome;  times  we  don't  keer 
if  we  live  or  die,  and  along  comes  Uncle 
John  with  one  of  his  side-bustin',  gun- 
totin'  musical  fests  which  makes  us 
plumb  ashamed  of  ourselves  for  even 
thinkin'  of  kicking  off!" 

And  through  all  this  good  Samaritan 
work  of  broadcasting  cheer  and  enter- 
tainment runs  that  indescribable  force 
— Personality.  Why,  the  entertainers 
selected  by  Uncle  John's  inborn  genius 
fairly  exude  it.  So  thoroughly  saturated 
with  it  are  these  skilled  entertainers  and 
educators  that  they  proceed  to  broadcast 
it  to  the  many  radio  fans  with  astonishing 
results.  You  can  feel  the  personality 
of  various  musicians,  vocalists  as  well 
as  pianists,  in  your  very  home.  Most 
miraculous  and  yet  a  pleasant  possi- 
bility in  this  day  and  time,  with  such 
a    genuinely    human    announcer    at   the 


helm   of   the     good    ship   Broadcast! 
And    not  all   of    Uncle    John's   pro- 
grams are  solely  entertainment.     Pro- 
fessor  Sylvester   Hert- 
zog     lectures     to     the 
youngsters,     in     the 
language    with 
7      wh 
fam 

subjects  which 
stimulate  thought 
action,  compelling 
them  subcon- 
sciously to  master 
precepts  and  quo- 
tations which  they 
thought  impossi- 
ble before.  This 
is  conducted  dur- 
ingthe  "Children's 
Hour,"  from  6:30 
to  7:30  p.  m.,  a 
time  which  all 
children  in  homes 
equipped  with 
radio  sets  hold 
most  sacred.  They 
are  also  treated  to 
special  readings 
from  the  Bible  by 
Uncle  John,  in  that  inimitable  voice 
which  children  recognize  as  readily  as 
they    do    their  parents. 

Another  feature  of  KHJ,  which  has 
aided  people  in  solving  their  daily  prob- 
lems, is  the  weekly  lectures  by  Fred  C. 
McNabb  on  the  "Care  of  Gardens." 
In  over  fifty-two  weeks  of  constant  broad- 
casting, Mr.  McNabb  has  done  such 
creditable  work  that  his  bulky  daily  mail 
from  grateful  housewives  attests  the 
results  obtained.  Then  Harold  Swartz, 
one  of  America's  most  promising  sculp- 
tors, delivers  a  weekly  lecture  on  "Art." 
"Care  of  the  Body"  talks  are  broadcast 
by  Dr.  Philip  M.  Lowell,  a  recognized 
authority  on  this  subject,  while  Cap- 
tain Salisbury  and  other  well-known 
globe-trotters  tell  of  their  thrilling 
experiences  in  foreign  countries. 

Talks  Easily  Understood 

"T\R.  MARS.  BAUMGARDT,  noted 


astronomer,  delivered 
every  Wednesday  eve- 
ning   for    over    a  year 
upon  astronomical  sub- 
jects, couched  in 
such  simple  lan- 
guage   that    the 
layman  could  ac- 
quire a  fair  work- 
ing  knowledge   of 
the  rather  myster- 
ious     science     of 
astronomy.      The 
"Radio       Philoso- 
pher," G.    Allison 
Phelps,  has  written 
and  broadcast  over 
thirty-six  essays 
on     momentous 
subjects,  which  are 
troubling      people 
in   the   ordinary 
walks  of  life.   Tak- 
ing   the     smudgy 
commonplaces     of 
life,  this  wise  phil- 


osopher animates  them  with  his  magic 
flow  of  metaphors  nad  similes,  so  that 
grim  bugbears  and  obstacles  are  soon 
converted  into  scintillating  rays  of 
sunshine. 

Queen  Titania 

ich  they  are  A  ND  last  but  not  least  of  the  legion  of 
niliar,  upon  -t*-  KHJ  broadcasters  is  the  famous 
Queen  Titania,  who  broadcasts  the  inner- 
most workings  of  Fairyland  every  Tuesday 
night.  In  conjunction  with  her  father, 
The  Sandman,  who  also  writes  and 
directs  these  unique  sketches,  Queen 
Titania  and  Uncle  John  broadcast  the 
most  instructuve  of  juvenile  programs, 
accompanied  with  the  most  melodious 
of  music. 

Hundreds  of  children,  ranging  from 
five  years  to  fifty,  throng  the  auditorium 
on  these  nights  and  are  taken  for  a 
pleasant  journey  through  the  mystic 
realms  of  Fairyland,  under  the  personal 
guidance  of  the  diminutive  Queen  Ti- 
tania. 

During  its  brief  existence  KHJ  has 
been  responsible  for  more  innovations, 
perhaps,  than  any  other  station  on  the 
Pacific  Coast.  In  addition  to  the  afore- 
mentioned features,  Uncle  John  has 
inaugurated  Saturday  morning  broad- 
casting classes.  All  persons  are  eligible, 
providing  they  register  in  advance. 
This  novel  Radio  instruction  is  deemed 
one  of  the  greatest  constructive  influences 
toward  a  better  understanding  of  radio. 

While  performers  appear  before  the 
microphone,  Uncle  John  stations  himself 
down  in  the  operating  room  the  better 
to  judge  of  the  pupil's  aptitude  at  broad- 
casting, and  at  its  conclusion  he  lectures 
to  the  class  upon  their  broadcasting 
from  a  radio  point  of  view.  This  con- 
structive criticism  is  also  broadcast, 
making  it  possible  for  all  members  of 
radioland  to  learn  the  profound  secrets 
of  broadcasting. 

When  we  radio  converts  shuffle  off  this, 
mortal  coil,  we  no  doubt  will  consult  the 
Recording  Angel  to  ascertain  our  respec- 
tive positions  on  the  great  list  of  those, 
who  served  their  Master  well  in 
•'A  radioland.      If  so,  we  no  doubt  will 

1|\  find  that  Uncle  John's  name,  like 
Abou  Ben  Adhem, 
heads  the  list. 


lecture 


E.  K.  Barnes  is  assistant  manager  of 
KHJ  and  the  boy  who  helps  keep  the 
wheels  moving  day  and  night  at  this 
ever-popular  havenof  "Kindness,  Hap- 
piness and  Joy." 


(The  fore- 
going account 
is  the  second  of 
an  interesting 
series  of  articles 
on  California 
radio  stations, 
which  are  known 
from  coast  to 
coast  for  their 
excellence.  The 
first  of  this 
series  appeared 
in  the  June 
RADIO  AGE, 
and  other  equal- 
ly interesting 
stories  will  be 
published  in  an 
early  issue.) 


30 


RADIO  AGE  for  July,  1925 


What  the  Broadcasters  Are  Doing 


Ten  Commandments  for  the 
Broadcast  Listener 


While  excellent  radio  reception  is  frequently  possible  during  the  warm  months,  the  best 
long  distance  records  come  in  the  Winter.  A  reasonable  attitude  will  help  the  listener 
here.  He  should  remember  that  he  cannot  expect  every  act  in  even  the  best  vaudeville 
performance  to  be  tremendously  amusing  and  just  what  he  wants,  nor  can  he  expect  the 
weather  every  day  to  be  clear  and  pleasant. 

Similarly  he  must  not  expect  every  day  to  be  just  right  for  long  distance  radio  reception. 
Now  and  then  a  Summer  storm  may  interfere  with  both  radio  and  picnics.  The  listener 
should  become  acquainted  with  his  local  stations  and  enjoy  them-  during  the  Summer, 
and  be  satisfied  with  the  long  distance  records  he  has  made,  or  will  make,  in  the  Winter. 
In  other  words,  he  should  get  the  best  there  is  in  radio  during  all  seasons,  and  above 
all  he  should  be  reasonable. 

•¥*+J»  *J+  *J*  »■*-*  »■*■«  •****,■*  %*  *J*  %■*  *{* 

If  the  listener  lives  rather  far  away  from  all  radio  broadcasting  stations  which  he 
wants  to  hear,  there  are  several  things  he  can  do.  He  can  lengthen  his  aerial  wires  and 
increase  their  height  from  the  ground.  Both  of  these  measures  make  the  signals  louder 
as  a  general  rule.  He  can  add  an  audio  frequency  amplifier  unless,  of  course,  he  already 
has  this  instrument.  He  can  also  increase  the  voltage  of  his  "B"  battery  or  plate  battery 
up  to  90  or  even  112  volts  (that  is,  to  four  or  five  of  the  usual  22^-voit  units  or  blocks). 
He  can  use  a  more  sensitive  loud  speaker,  or  content  himself  with  head  set  operation. 
He  should  also  tune  more  carefully  so  as  to  get  the  very  loudest  signal  which  his  set  is 
capable  of  giving.  If  there  is  a  tickler  adjustment  on  his  set,  he  should  learn  how  to 
use  it  so  as  to  get  full  volume  of  signals.  And  he  should  remember  that  the  good 
results  he  will  then  get  are  going  to  be  even  better  results  in  the  Winter. 

If  the  listener  is  very  near  a  powerful  broadcasting  station,  he  may  get  excessively  loud 
signals  from  that  station  and  have  difficulty  in  picking  up  other  stations  when  the  nearby 
station  is  in  operation.  In  extreme  cases  it  is  not  possible  to  get  the  distant  station  at 
all  under  such  circumstances  any  more  than  it  is  possible  to  hear  a  whisper  from  a  dis- 
tance when  someone  else  is  shouting  nearby.     Still  a  good  deal  can  be  accomplished. 

•?■**■*■••■*■♦  (S*  •*+***  ******  **"■*  *********** 

There  are  ten  good  rules  for  broadcast  listeners: 


1.  Don't  try  to  hear  Australia  in  mid- 
summer. Be  satisfied  to  enjoy  the  nearer 
stations  most  of  the  time. 

2.  Don't  be  disappointed  if  an  occasional 
storm  interferes  with  your  radio  evening. 
There  are  many  fine  concerts  coming.  You 
can't  expect  to  find  a  pearl  in  every  oyster 
nor  to  receive  a  record-breaking  concert 
every  night. 

3.  If  you  want  louder  signals,  use  a 
longer  aerial,  more  tubes,  higher  plate 
voltage,  more  sensitive  loud  speakers  and 
more  careful  tickler  and  receiver  adjust- 
ment. 

4.  A  pleasant  signal  filling  a  moderate 
size  room  should  be  enough  to  give  satis- 
faction. It  is  not  worth  while  producing 
signals  which  deafen  the  neighbors.  It  is 
wasteful  to  insist  on  tremendous  signals 
which  are  generally  less  pleasant  than 
moderate  signals. 

5.  If  your  local  station  comes  in  too 
loudly  and  drowns  others  out,  a  smaller 
aerial  will  help  in  tuning  him  out,  with  a 
smaller  condenser  connected  between  aerial 
and  ground.  And  if  all  measures  to  get 
rid  of  the  local  station  fail,  why  not  enjoy 
his  concerts?  He  is  working  hard  for  you 
and  it  is  nobody's  fault  that  you  are  so 
close  to  him  that  you  are  bound  to  hear 
him.  Broadcast  stations  have  to  be  closer 
to  some  people  than  to  others. 


6.  For  the  new  longer  waves  above  450 
meters,  use  a  condenser  connected  between 
the  aerial  and  ground  terminals  of  your  set. 

7.  A  little  patience  in-  learning  to  handle 
your  receiver  yields  rich  returns  in  satis- 
faction from  fine  signals.  Remember  that 
"Rome  wasn't  built  in  a  day"  and  keep  on 
getting  more  and  more  familiar  with  your 
set  and  how  it  works. 

8.  It  is  a  good  idea  to  read  the  radio 
column  of  a  newspaper  or  a  good  radio 
magazine  or  two.  It  helps  you  to  know" 
how  your  set  works  and  keeps  you  up-to- 
date  in  radio.  Information  of  this  sort  is 
an  aid  in  getting  the  concerts  loud  and 
clear. 

9.  Ask  your  radio  dealer  for  advice;  he 
can  probably  tell  you  what  you  want  to 
know  and  will  be  glad  to  do  so.  The 
manufacturer  of  your  set  is  also  willing  to 
help  you  get  the  desired  results  from  its 
use. 

10.  Do  not  throw  away  the  direction 
sheets  or  booklet  that  came  with  your  set 
and  with  the  tubes.  Read  all  such  material 
carefully  now  and  then.  If  you  have  lost 
the  direction  sheets  write  to  the  dealer  or 
manufacturer  for  another.  The  direction 
sheets  answer  most  of  the  questions  which 
have  been  puzzling  you  and  preventing  you 
from  getting  the  best  out  of  your  set. 


(Copyright.  1926.  by  Radio  Aee.  Inc.] 


RADIO  AGE  for  July,  1925 


What  the  Broadcasters  A  re  Doir.g 


31 


Favorites  of  MOVIEDOM  Give 
Snappy  Show  at  WIP 


Fans  Get 

Real  Insight 

Into  Adventures 

of  Famous 

Stars 


PHILADELPHIA: — One  of  the  most  unusual  gatherings 
of  famous  stage  and  screen  folk  was  held  last  month. 
Moving  picture  stars  of  the.  Metro-Goldwyn  picture  cor- 
poration, together  with  such  famous  men  as  Marcus  Loew 
and  noted  stage  stars,  gathered  around  the  microphones  in 
the  Studio  of  Station  WIP,  the  radio  broadcaster  of  the  Gimbel 
store,  to  entertain  the  radio  public  and  to  answer  all  personal 
questions  sent  in  to  the  station. 

It  was  a  real  party — the  stars  sang,  dined,  danced  to  two 
orchestras;   and   the   microphones   did   full  duty  all  the  while. 

Lillian  Gish,  Jackie  Coogan,  Barbara  LaMarr,  Johnny 
Hines,  Mae  Busch,  Dorothy  Mackaill,  Marion  Davies,  Anita 
Stewart,  Harry  Morey,  Dagmar  Godowsky,  Louise  Glaum, 
Fritzi  Brunette,  Ben  Finney,  Flora  LaBreton  and  many  more 
screen  players. 

Raymond  Hitchcock,  Eddie  Cantor  of  "Kid  Boots"  fame, 
with  Mary  Eaton  and  her  sisters,  Doris  and  Pearl,  Cecil  Lean 
and  Cleo  Mayfield  who  made  "No,  No,  Nanette"  famous  and 
the  leading  men  and  women  of  the  two  "Music  Box  Revue" 
shows  represented  the  stage  and  Broadway.    Nils  T.  Granlund, 


I 


Above,  Jackie  Coogan  in  a  speculative  mood  before  appearing 
before  the  WIP  "mike"  and  telling  his  innermost  secrets  to  a  host 
of  radio  admirers.  Mae  Busch,  popular  leading  lady,  is  the  de- 
mure miss  at  the  lower  left.  She  was  one  of  the  principal  speak- 
ers on  this  alt-star  movie  program  from  the  Philadelphia  station. 

famous  "N.  T.  G."  of  Station  WHN  in  New  York  City;  Mar- 
cus Loew,  president  of  the  Metro-Goldwyn  Picture  Corpora- 
tion and  head  of  the  Loew  chain  of  theatres,  and  the  great 
"Sir  Joseph"  Ginzburg,  Broadway's  biggest  "nut." 

Plenty  of  Humor 

ELI  M.  OROWITZ,  the  famous  "Emo"  whose  weekly  movie 
broadcasts  from  Station  WIP  have  created  a  sensation 
all  over  the  country,  arranged  the  party  and  was  the  announcer 
for  the  evening.  "Emo's"  witty  remarks,  aided  by  those  of 
Johnny  Hines,  to  say  nothing  of  the  other  comedians  present, 
made  the  radio  sets  bulge  with  laughter. 

The  party  was  strictly  informal.  Most  of  the  stars  spoke 
on  the  impulse  of  the  moment.  The  movie  fans  who  have 
seen  their  favorite  screen  star  as  many  times  as  they  possibly 
can,  had  the  opportunity  to  hear  their  voices. 

And  if  you  wondered  why  Dorothy  Mackaill  bobbed  her 
hair,  or  just  what  Barbara  LaMarr  thinks  of  vamps,  or  any 
of  a  thousand  questions  that  run  through  movie  fan's  heads, 
you  found  out  if  you  heard  this  unique  program. 

This  idea  of  having  movie  stars  speak  from  big  broadcasting 
stations  is  meeting  with  more  and  more  favor  every  day.  For 
instance,  at  WGN,  Chicago,  recently,  according  to  dispatches 
received  at  WIP,  Gloria  Swanson,  the  prominent  Hollywood 
resident  and  fashionably  cinema  actress,  consented  to  be 
"interviewed"  by  the  Announcer,  the  questions  in  the  inter- 
view having  been  sent  in  by  interested  listeners.  This  is  but 
one  example  of  how  movie  stars  are  gaining  wonderful  publicity 
for  themselves  as  well  as  providing  more  or  less  amusement. 


32 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hoar 


Look  Out  for 


"THE  RADIO  SPIES" 

By  FREDERICK  A.  SMITH 

Editor,  Radio  Age 


IT  IS  somewhat  noticeable  that  in 
spite  of  the  sensational  nature  of 
charges  made  against  the  Radio 
Corporation  of  America  in  the  New 
Jersey  Courts,  comparatively  few  radio 
publications  and  newspapers  gave  pub- 
licity to  the  astonishing  accusations  made 
by  the  De  Forest  Radio  Company. 
RADIO  AGE  is  publishing  these  facts 
for  the  reason  that  both  parties  to  the 
prosecution  are  big  factors  in  the  radio 
industry.  We  believe  that  it  is  due  our 
readers  to  tell  them  the  truth  about  this 
industrial  scandal,  not  permitting  the 
fact  that  the  Radio  Corporation  of 
America  is  the  biggest  radio  advertiser 
in  the  field  to  deter  us  from  adhering  to 
the  straight  line  of  editorial  responsibility. 
Among  publications  which  have  given 
space  to  this  situation  are  The  New 
York  Times,  New  York  Herald-Tribune, 
Chicago  Herald  and  Examiner,  Radio 
Retailer  and  Jobber,  and  Radio  Guide. 
There  are  a  few  others,  but  the  pub- 
lications named  have  come  to  our 
hands  and  we  know  that  many  publica- 
tions did  not  make  room  in  their  columns 
for  a  line  of  this  publicity.  While  it 
may  be  extremely  unpleasant  to  the 
Radio  Corporation  of  America  to  have 
these  court  proceedings  reported  to  the 
public,  we  will  assume  that  the  Corpora- 
tion will  welcome  a  full  investigation  of 
the  charges  and  will  be  willing,  as  a 
Corporation  admitting  it  was  organized 
for  patriotic  purposes,  to  accept  the 
judgment  of  the  American  public  as  to 
whether  it  has  done  wrong. 

Briefly,  the  De  Forest  Radio  Company, 
on  May  1,  1925,  obtained  an  injunction  in 
Trenton,  N.  J.,  restraining  the  Radio 
Corporation  of  America  from  attempting 
to  steal  business  and  scientific  secrets 
from  the  De  Forest  Radio  Company. 
The  injunction  was  granted  after  Vice 
Chancellor  Backes  had  read  affidavits 
and  other  documents  tending  to  support 
the  charge  that  the  Radio  Corporation 
of  America  had  introduced  spies  into 
the  plant  and  offices  of  the  De  Forest 
Radio  Company  and  that  the  Radio 
Corporation's  secret  agents  had,  with 
bribes  of  money,  seduced  employes  of  the 
De  Forest  Radio  Company  into  acts  of 
treachery. 

We  publish  the  following  from  the 
New  York  Times  of  May  5,  1925: ' 

The  Radio  Corporation  of  America  maintained 
secret  offices  at  25  Beaver  Street,  where  its  special 
investigators,  known  only  by  code  numbers,  reported 
the  results  of  their  espionage  on  the  DeForest  Radio 
Company  and  other  concerns,  according  to  affidavits 
filed  yesterday  in  the  Chancery  Court  of  New 
Jersey.  The  papers  were  filed  to  support  the  injunc- 
tion suit  of  the  De  Forest  Radio  Company  against 
the  Radio  Corporation  of  America,  brought  last  week 
at  Trenton. 

The  affidavits  alleged  that  agents  of  the  Radio 
Corporation  of  America  in  the  De  Forest  Radio 
Company's  plant  furnished  John  S.  Harley,  chief 
special  agent  of  the  Radio  Corporation,  with  valuable 
information  concerning  secret  methods  of  manu- 
facturing radio  apparatus,  as  well  as  the  names  and 
addresses  of  employes,  the  number  of  radio  tubes 
produced,  addresses  of  persons  and  concerns  dealing 
with  the  De  Forest  Company,  notices  posted  in  the 
various  departments,  changes  in  the  personnel, 
efforts  made  to  speed  up  production,  and  especially 
.    what  took  place  in  the  power  tube  department. 

The  information  alleged  to  have  been  passed  on  to 


the  Radio  Corporation  of  America  also  included 
drawings  of  machines  and  samples  of  products  made 
by  the  De  Forest  Company. 

Details  of  how  Harley  is  alleged  to  have  placed 
his  agents  in  the  De  Forest  establishment  and  of  his 
employment  of  De  Forest  employes  to  furnish  him 
with  stolen  information  are  also  contained  in  the 
affidavits. 

General  Electric  Accused 
President  Theodore  Luce  of  the  De  Forest  Radio 
Company,  in  an  affidavit,  alleges  that  the  General 
Electric  Company,  with  which,  he  asserted,  the  Radio 
Corporation  was  in  combination,  had  succeeded  in 
buying  up  the  Electron  Relay  Company  of  Toledo, 
and  cut  off  from  the  De  Forest  Company  its  source 
of  filament  wire. 

"If  the  defendant  and  its  associates,  the  General 
Electric  Company  and  the  Westinghouse  Electric 
and  Manufacturing  Company,  can  control  the  fila- 
ment wire  output,  they  can,  of  course,  prevent 
competition  in  vacuum    tubes,"   he  adds. 

No  statement  was  forthcoming  yesterday  from  the 
Radio  Corporation  of  America  in  connection  with 
the  filing  of  the  affidavits.  General  J.  G.  Harbord, 
President  of  the  corporation,  declined  to  comment. 
Vice  President  David  Sarnoff  was  out  of  town. 

The  charges  of  commercial  espionage  and  theft 
of  valuable  business  information  are  contained  in 
great  detail  in  the  affidavit  of  Charles  F.  Bowlby, 
cost  accountant  of  the  De  Forest  Company,  em- 
ployed by  them  between  1921  and  1923,  who  worked 
for  the  Radio  Corporation  from  the  early  months  of 
1923  until  April  or  May,  1924.  Since  Feb.  23.  1925. 
he  has  again  been  employed  by  the  De  Forest  Com- 
pany. 

Bowlby's  employment  by  the  Radio  Corporation 
came  about  in  this  way,  he  says: 

Prior  to  leaving  the  De  Forest  concern  he  was  told 
by  his  fiancee.  Mildred  Michael,  a  co-employe,  that 
a  man  who  gave  the  name  of  "Jameson,"  and  who 
claimed  to  have  met  her  at  a  radio  dinner,  had 
telephoned  her  for  an  appointment.  Bowlby  met 
"Jameson"  at  his  financee's  home.  Her  sister 
Madeline  was  present. 

"Jameson"  said  he  knew  nothing  about  the 
details  of  the  radio  business  but  was  devoting  him- 
self to  the  merger  of  various  radio  companies.  He 
said  he  had  been  informed  that  there  was  some 
relation  between  the  De  Forest  Company  and  the 
Radiocrafts  Company,  and  asked  Bowlby  and  his 
fiancee  many  questions  about  the  De  Forest  Com- 
pany, how  it  kept  its  books,  cost  records,  production 
records,  stock  records,  payroll  and  other  records, 
saying  that  such  information  would  be  useful  to 
him  in  connection  with  the  enterprise  on  which  he 
was  engaged. 

Hears  More  of  "Jameson" 
Two  weeks  after  the  meeting  with  "Jameson," 
Bowlby  was  told  by  William  W.  Buckbee.  an  employe 
in  the  De  Forest  laboratory,  that  he  had  been  asked 
by  an  employe  of  the  Radio  Corporation  of  America, 
calling  himself  "Hurley,"  for  information  regarding 
instruments  made  by  the  De  Forest  Company;  that 
he  had  been  asked  to  furnish  drawings  of  such  instru- 
ments; that  he,  Buckbee,  several  times  met  a  man 
who  called  himself  "Hurley."  The  latter  was  ac- 
companied by  a  young  woman  called  "Miss  John- 
son." Buckbee  said  he  knew  her  to  be  a  De  Forest 
employe.  Buckbee's  description  of  "Hurley"  tallied 
with  Bowlby's  recollection  of  "Jameson,"  and 
Bowlby  was  satisfied  they  were  the  same  person. 

At  that  time,  Bowlby  called  on  Miss  Johnson  in 
the  De  Forest  plant  and  questioned  her  concerning 
her  relationship  with  the  Radio  Corporation  of 
America.  She  denied  she  was  in  any  way  interested 
in  the  Radio  Corporation,  but  Bowlby  did  not 
believe  her  and  obtained  her  discharge. 

In  February,  1923,  Bowlby  married  Miss  Michael 
and  the  following  April  he  left  the  employ  of  the  De 
Forest  Company.  Subsequently  his  wife  was  dis- 
charged. Then  he  sought  employment  with  the 
Radio  Corporation.  While  calling  on  a  friend  at  the 
233  Broadway  offices  of  the  Radio  Corporation. 
"Jameson"  stepped  into  the  room  and  recognized 
him.  says  Bowlby.  He  handed  Bowlby  a  card  on 
which  was  printed  "John  S.  Harley,  Chief  Special 
Agent,  Radio  Corporation  of  America,  64  Broad 
Street."      He    called    on    Harley.   and    found    Miss 


Johnson  in  the  office.     Bowlby's  affidavit  reads  as 
follows: 

"She  then  admitted  in  the  presence  of  Mr.  Harley 
that  at  the  time  I  had  questioned  her  she  was  in  the 
employ  of  the  Radio  Corporation  of  America,  and 
that  she  had  secured  her  position  with  the  De  Forest 
Radio  Company  under  instructions  from  Harley. 
Harley  confirmed  her  statement,  and  they  joked 
about  my  catching  Miss  Johnson  at  the  De  Forest 
plant,  and  that  I  had  procured  her  discharge,  and 
now  I  was  seeking  employment  with  the  Radio  Cor- 
poration of  America." 

At  Harley's  request  Bowlby  took  his  wife  to  the 
Broad  Street  office  of  Harley,  who  said  he  had  other 
operatives  in  the  De  Forest  plants  besides  Miss 
Johnson.  He  offered  Mrs.  Bowlby  a  position,  which 
she  refused. 

Offices  Kept  Secret 
Bowlby  was  employed  as  special  investigator  under 
Harley  from  May,  1924,  until  January,  1925,  and  he 
reported  regularly  in  writing  to   Harley  in  Rooms 
301,  302  and  303,  at  25  Beaver  Street. 

"These  were  secret  offices,"  he  says,  "and,  as  I  was 
informed,  were  known  only  to  certain  officers  of  the 
Radio  Corporation  of  America.  There  was  nothing 
on  the  doors  of  the  offices  or  on  the  bulletin  board 
of  the  building  to  indicate  that  Harley  or  the  Radio 
Corporation  of  America  had  any  offices  in  that 
building;  in  fact  there  was  nothing  upon  the  doors 
of  those  offices  except  the  room  numbers. 

"While  in  the  employ  of  the  Radio  Corporation, 
Harley  asked  him,  Bowlby  alleges,  to  purchase 
radio  tubes  and  roll  filament  wire  from  the  De 
Forest  Company,  and  to  obtain  the  names  of  persons 
or  firms  from  which  the  De  Forest  Company  was 
purchasing  its  filament  wire.  He  had  been  unable  to 
do  so,  and  Harley  said  he  was  particularly  interested 
in  obtaining  the  names  of  the  makers  of  the  apparatus 
in  the  tube  department,  and  of  the  high  frequency 
bombarders  used  in  the  De  Forest  plant.  He  wished 
to  have  a  diagram  of  the  layout  of  the  tube  depart- 
ment, giving  the  names  and  locations  of  all  the 
machines. 

"He  asked  me  to  get  a  position  with  the  De  Forest 
Radio  Company  as  a  means  of  getting  this  informa- 
tion for  him,  at  the  same  time  continuing  in  the 
employ  of  the  Radio  Corporation  of  America," 
asserts  Bowlby. 

Continuing,  Bowlby  says  he  told  Harley  he  could 
not  obtain  employment  with  the  De  Forest  Com- 
pany, but  said  that  Henry  Thies.  a  former  De  Forest 
employe  might  be'  able  to  get  the  information. 
Harley  directed  him  to  employ  Thies  for  that  pur- 
pose. He  took  Thies  to  Harley  who  told  him  what 
he  desired.  Two  weeks  later  he  met  Thies  in  Room 
217  of  the  secret  Beaver  Street  offices,  "the  room 
where  the  investigators  were  accustomed  to  go  when 
they  came  in  from  their  work  and  where  some  of 
them  wrote  up  their  reports." 

Bowlby  says  he  suggested  that  Thies  obtain  re- 
employment with  the  De  Forest  Company.  Harley 
thought  it  a  good  idea  and  directed  Thies  to  make 
prompt  application. 

"During  the  whole  time  that  I  was  working  for 
the  Radio  Corporation  of  America  I  was  under  the 
supervision  and  direction  of  Harley,  but  I  was  always 
paio.  by  the  check  of  Radio  Corporation  of  America," 
Bowlby's  affidavit  continues. 

Known  as  "C-l" 
"While  I  was  employed  by  the  Radio  Corpora- 
tion I  was  designated  as  'C-l'  and  made  all  reports 
under  that  designation.  I  never  signed  my  own 
name  to  any  reports.  When  I  telephoned  to  Harley, 
as  I  frequently  did,  I  always  identified  myself  under 
that  designation,  never  by  any  name.  I  know,  of 
my  own  knowledge,  that  all  employes  working  under 
Harley  went  by  initial  letters  and  numbers,  as  I 
would  meet  them  in  the  room  where  their  reports 
were  being  made  out  and  they  would  tell  me  their 
designations  and  I  would  see  these  designations  on 
the  reports  which  they  were  preparing. 

"While  employed  by  the  Radio  Corporation  of 
America,  I  frequently  met  Cecelia  Lambert  at 
Harley's  office  and  I  knew  her  as  'C-3.'  She  was 
doing  investigating  work  and  reporting  to  Harley 
under  that  designation.  Since  my  recent  employ- 
ment by  the  De  Forest  Company  I  have  on  several 
(Continued  on  page  51) 


RADIO  AGE  for  July,  1925 


What  the  Broadcasters  are  Doing 


33 


Dorothy  and  Mar- 
jorie  Moline  are  de- 
termined to  get  across 
Jack  Nelson's  juven- 
ile idea  even  if  they 
have  to  dress  the 
part,  as  shown  in  the 
photo.  Naturally, 
they  have  succeeded 


How  the  Alert  Jack  Nelson  is 


Making  Us  CHILDREN  Again 

RADIO  SHOULDN'T  BE  TOO  SOLEMN,  IS  HIS  DOCTRINE 


JACK  NELSON  is  a  great  favorite 
among  the  kiddies.  His  best  claim 
to  fame  in  that  line  lies  in  the  fact 
that  he  has  lived  among  thousands  of 
orphan  boys  and  girls  at  Mooseheart, 
111.,  the  city  founded  by  the  Loyal  Order 
of  Moose  to  care  for  children  of  de- 
ceased members.  In  his  capacity  of 
director  of  the  Mooseheart  radio  station, 
WJJD-,  Jack  came  in  contact  daily  with 
these  children,  who  formed  a  large  part 
of  the  station's  daily  programs — and  still 
do.  Consequently  he  knows  whereof 
he  speaks  in  the  juvenile  line. 

After  several  years  of  broadcasting 
experience,  Mr.  Nelson  is  prepared  to 
announce  that  radio  listeners,  whether 
young  or  old,  like  to  be  reminded  they 
were  children  once.  They  prefer  this 
reminder    more    than    thev    do    solemn 


speeches,  sad  music  and  uninteresting 
programs,  according  to  Jack.  He  is  an 
ardent  believer  in  the  policy  that  any- 
thing light-hearted  and  juvenile  will  "go 
over"  with  a  radio  audience  much  better 
than   any   other   form   of  entertainment. 

By  this  Jack  does  not  advocate  a  con- 
tinual round  of  bedtime  stories,  for  he 
has  never  featured  that  sort  of  broad- 
casting. He  does,  however,  believe  in 
keeping  people  young — anywhere  from 
12  to  20,  he  says,  and  in  the  attainment 
of  that  ideal  he  has  mapped  out  some 
wonderful  programs  that  have  won  an 
instantaneous  response  among  fans  all 
over  the  country  who  have  learned  to 
listen  regularly  for  the  programs  from 
WJJD  every  night  after  10:30  o'clock, 
on  a  wavelength  of  302  meters. 

For     example,     the      Moline     sisters, 


popular  vaudeville  artists,  come  attired 
as  little  girls  when  they  enter  Jack's 
studio  in  the  Palmer  House,  Chicago. 
Not  that  the  listeners  can  see  them,  but 
Jack  describes  them  picturesquely  and 
then  lets  them  "do  their  stuff."  They 
cut  up  for  all  they're  worth,  and  the 
radio  waves  virtually  ripple  with  laugh- 
ter. The  girls  don't  exactly  act  foolishly 
kiddish,  but  they  are  funny  and  light- 
hearted,  and  that's  the  kind  of  spirit 
Jack  wants  to  send  out  from  WJJD  on 
his  popular  programs. 

At  other  times  the  children  themselves 
broadcast  from  Mooseheart,  and  some- 
times little  kiddies  of  7  years  of  age  make 
the  announcements.  All  this  makes  a  tre- 
mendous "hit"  with  the  listeners,  and  no 
doubt  in  the  near  future  WJ  J  D  will  prob- 
ably mean  "Watch  Jack's  Joy  Diggers." 


34 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Radio  Age  Institute 

Manufacturers'  Testing  Service 

ATEMBERS  of  the  staff  of  RADIO  AGE  will  be  pleased  to  test  devices 
■*■  _  and  materials  for  radio  manufacturers  with  the  object  of  deter- 
mining their  efficiency  and  worth.  All  apparatus  which  meets  with 
the  approval  of  various  tests  imposed  by  members  of  the  technical 
staff  of  RADIO  AGE  will  be  awarded  our  endorsement,  and  the  seal 
shown  to  the  right  will  be  furnished  free  of  charge.  Materials  for 
testing  should  be  sent  to 

RADIO  AGE  INSTITUTE 

504  N.  Dearborn  Street,  Chicago,  111. 


DEVICES 

displaying  this  seal 
have  been  tested 
and  approved  by 
the  RADIO  AGE 
INSTITUTE. 

Apparatus  illus- 
trated and  de- 
scribed below  has 
successfully  passed 
our  tests  for  July, 
1925. 


Test  No.  70,  WET  "B"  BATTERIES,  submitted 
by  the  Kelman  Electric  Co.,  Rochester,  N.  Y.  Con- 
sists of  twelve  cells  in  glass  jars,  set  in  a  wooden  frame- 
Tops  are  provided  with  vents  for  filling  with  distilled 
water.  There  is  a  sufficient  plate  area  to  allow  a 
generous  milliampere  capacity  for  use  in^receiving 
sets  where  a  wet  B  battery  is  desired.  A  card  giving 
detailed  instructions  for  filling  the  battery  originally, 
and  for  watering  and  charging  it,  accompanies  the 
battery,  which  arrived  in  good  condition  as  a  result 
of  good  packing.  Tested  and  approved  by  RADIO 
AGE  Institute. 


Test  No.  71,  CONTINENTAL  2-GANG  CON- 
DENSER. Submitted  by  Gardner  and  Hepburn, 
Inc.,  2100  Washington  Ave.,  Philadelphia,  Pa.  Con- 
sists of  a  two  gang  variable  condenser,  well  made  and 
suitable  where  tuning  of  two  inductances  simul- 
taneously is  desired.  Or  it  can  be  used  with  the  two 
halves  in  series  to  decrease  the  capacity  of  the  con- 
denser.   Tested  and  approved  by  RADIO  AGE  In- 


Test  No.  72,  CONTINENTAL  LOW  LOSS  AND 
JUNIOR  CONDENSER.  Submitted  by  Gardner 
and  Hepburn,  Philadelphia,  Pa.  It  is  known  as  the 
Continental  lo-Ioss  condenser,  with  the  vernier 
arrangement  consisting  of  the  Junior  condenser 
shown  at  the  bottom  of  the  above  illustration.  It  can 
be  used  separately  or  in  parallel  with  the  lo-loss  as 
a  means  of  fine  tuning.  Tested  and  approved  by 
RADIO  AGE  Institute. 


Test  No.  73.  KELLOGG  SHIELDED  TRANS- 
FORMERS. Codes  503  and  504  were  tested,  having 
been  submitted  by  the  makers,  the  Kellogg  Switch- 
board and  Supply  Company,  1066  W.  Adams  St., 
Chicago,  111.  These  unshielded  types  of  audio  trans- 
formers are  of  4  1-2  to  1  and  3  to  1  ratio  respectively, 
and  over  a  period  of  strenuous  tests  were  found  to 
produce  a  really  distortionless  amplification,  consis- 
tently. The  design  is  exceedingly  simple,  very  high 
grade  wire  being  used.  The  tops  are  of  sheet  bakelite. 
Satisfactorily  passed  the  tests  and  requirements  of 
the  RADIO  AGE  Institute. 


Test  No.  74,  FILAMENT 
WARNING  SWITCH.  Sam- 
ple submitted  by  The  Yaxley 
Mfg.  Co.,  1103  W.  Monroe 
St.,  Chicago,  111.  Consists  of 
a  single  hole  mounting  fila- 
ment switch  and  socket  for  a 
miniature  light,  the  light  in 
parallel  across  the  A  battery 
through  the  switch  so  that 
while  current  is  on  the  light  is 
illuminated,  giving  warning 
current  is  being  used.  This 
light  sits  back  of  the  panel 
and  a  bezel  of  colored  glass 
permits  the  set-owner  to  see 
it.  It  serves  as  a  warning  to 
the  radio  fan  who  gets  ready 
to  turn  in  after  a  strenuous 
DX  chase  that  his  filaments  are  still  lit,  and  should 
be  extinguished  in  the  interest  of  battery  economy. 
Tested  and  approved  by  RADIO  AGE  Institute. 


Test  No.  75,  REMOTE  CON- 
TROL LIGHT.  Also  submitted 
by  the  Yaxley  Mfg.  Co.,  of  Chi- 
cago, III.  This  device  consists  of 
a  single  hole  mounting  brace  and 
socket  for  miniature  light,  for  use 
at  a  point  other  than  right  on  the 
battery  switch.  It  is  known  as  a 
remote  control  light.  It  also 
serves  as  a  warning  that  filaments 
are  lighted.  Tested  and  approved 
by  the  RADIO  AGE  Institute. 


No.  310 


A  ROUNDUP  OF 
HOOKUPS— 

Something  you've  never 

seen  before 

in  the  August 

RADIO    AGE 


Test' No.  76, 
STRAIGHT-LINE- 
WAVELENGTH  CON- 
DENSER. Submitted 
by  the  manufacturers, 
Silver-Marshall,  Inc.,  of  , 
110  S.  Wabash  Av 
Chicago,  111.  This  con- 
denser is  a  new  low 
loss  condenser  designed 
for  perfect  S-L-W  tun- 
ing. It  is  of  the  single- 
bearing  type,  equipped 
with  a  long  cone  brass  bearing,  adjustable,  and  tension 
adjustment  mounted  on,  but  independent  of,  the 
bearing.  All  plates  are  of  heavily  hardened  and 
flattened  brass,  entirely  silver-plated,  as  are  all  cur- 
rent-carrying surfaces.  This  feature,  in  conjunction 
with  the  use  of  a  minimum  of  high-grade  insulation 
well  out  of  the  electro-static  field,  results  in  this  con- 
denser having  even  lower  losses  than  many  laboratory 
standards.  The  single  end-plate,  as  well  as  the  shape 
of  the  plates,  is  responsible  for  the  very  low  minimum 
capacity  and  the  exceptionally  high  capacity  ratio. 

Instead  of  separating  by  wavelengths,  with  this 
new  S-L-W  condenser  it  is  possible  to  separate  stations 
by  kilocycles,  thus  insuring  greater  selectivity  and 
more  separation  of  stations.  Comprises  latest  design 
in  low  loss  construction.  Tested  and  approved  by 
RADIO  AGE  Institute. 


Test  No.  77,  JEWETT  SUPERSPEAKER  CON- 
SOLE. A  quality  loud  speaker,  submitted  by  the 
Jewett  Radio  and  Phonograph  Company  of  Pontiac, 
Mich.  The  horn  in  the  Superspeaker  console  is  made 
of  the  same  materials  as  the  super-speaker  horn,  with 
the  exception  that  the  final  finish  coats  being  enclosed, 
are  not  necessary.  The  horn  floats  within  the  cabinet, 
and  is  thoroughly  padded  on  three  sides  with  piano 
felt,  there  being  a  resonance  chamber  below  the  horn, 
which  adds  greatly  to  the  excellent  tonal  qualities 
produced  by  this  speaker.  The  unit  is  of  the  Jewett 
Vemco  Design.  Tested  and  approved  by  RADIO 
AGE  Institute. 


Test  No.  78,  REMO  RADIO  TUBE  REVIVER. 
Submitted  by  the  manufacturers,  the  Remo  Corpora- 
tion, of  Meriden,  Conn.  This  device  was  put  on  the 
market  in  response  to  the  popular  demand  for  a  tube 
reviver.  The  Remo  reviver  has  two  sockets,  for 
large  and  small  tubes,  and  tests  showed  that  tubes 
waning  in  efficiency,  if  placed  in  the  Remo  reviver, 
would  practically  regain  their  old  life.  Certain 
periods  of  time,  according  to  the  degree  of  age  in  the 
tube  being  tested,  were  necessary.  The  reviver 
connects  to  the  electric  light  socket.  Tested  and 
approved  by  RADIO  AGE  Institute. 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


35 


A  Timely  Discourse  on 

Conventional  Radio  Symbols  and 
Crystal  Detector  Sets 


By  JOHN  B.  RATHBUN 


Copyright:    1925 


CONVENTIONAL  radio  circuit  dia- 
grams, the  short-hand  of  radio,  have 
always  proved  a  sticker  to  the  tyro  in 
this  science,  and  it  is  certain  that  many  a 
prospective  builder  has  contracted  a  bad 
case  of  cold  feet  and  quit  the  game  when 
he  was  brought  face  to  face  with  the 
curley-cues  and  zig-zag  lines  of  the  tech- 
nical diagram.  Not  being  very  familiar 
with  the  apparatus  itself,  it  is  no  wonder 
that  the  prospect  of  learning  still  more 
of  the  technique  filled  him  with  dismay. 

However,  when  these  symbols  are  once 
understood,  they  are  more  easily  read 
and  understood  than  the  picture  diagrams 
for  they  show  the  functioning  and  general 
principles  of  the  circuits  far  more  clearly 
to  the  experienced  eye  than  pictures  of 
the  apparatus.  You  can  see  the  course 
taken  by  the  current  in  the  different 
branches  of  the  circuit  at  a  glance,  and 
can  immediately  classify  the  circuit  with 
little  chance  of  error;  something  that 
I  have  never  yet  been  able  to  do  with  the 
picture  type.  However,  the  picture 
diagram  has  its  place  in  the  scheme  of 
things  where  the  reader  is  not  interested 
in  theory,  but  simply  in  building  some- 
thing that  will  bring  in  the  voice  and 
music  with  the  least  delay  and  study. 

For  the  benefit  of  those  who  have  not 
yet  become  familiar  with  the  standard 
conventional  .symbols  used  in  radio  cir- 
cuit diagrams,  I  have  prepared  the  ac- 
companying two  pages  of  blueprints  in 
which  the  more  common  symbols  and 
abbreviations  have  been  defined.  In  ad- 
dition to  the  listing  of  the  symbols,  I 
have  taken  up  a  short  description  of  the 
various  parts  used  in  the  receiving  cir- 
cuits so  that  the  subject  will  be  more 
easily  followed. 

Circuit  Symbols  (Sheet  No.  1) 

1.  INDUCTANCE  (Air  Core  Type).  The 
hollow  coil  of  wire  or  other  inductance  coil  with  an 
air  core  is  shown  by  a  continuous  scroll  or  helix 
as  in  Item  No.  1.  Its  purpose  is  to  choke  back  or 
impede  the  flow  of  radio  frequency  current  or  for 
tuning   radio    circuits    to   the   wavelength   of  the 

Blueprints  of  Conventional  Radio  Symbols  and  Typical  Crystal  Receivers  on  pages  36,  37,  40  and  41 


How  to  Understand 
All  Radio  Symbols; 
Giving  the  Crystal 
Its  Merited  Attention 


transmitting  station.  The  abbreviation  is  the 
letter  (L)  and  its  magnitude  is  generally  expressed 
in  millihenries,  or  by  the  number  of  turns  of  wire. 

2.  IRON  CORE  CHOKE.  This  consists  of  a 
great  many  turns  of  wire  wound  around  a  core  of 
soft  steel  wire  or  thin  steel  sheets  called  "lamina- 
tions." It  is  used  when  a  greater  retardation  must 
be  had  than  is  convenient  with  an  air  core  choke, 
and  can  choke  back  audio  as  well  as  radio  frequency 
currents.    Values  in  henries  or  millihenries. 

3.  TRANSFORMER-COUPLER  (Air  Core 
Type).  This  transformer  for  radio  frequency 
currents  consists  of  two  coils  of  wire  called  respec- 
tively the  PRIMARY  (PRI.),  and  the  SECON- 
DARY (SEC.)  coils.  Radio  frequency  currents 
passing  through  the  primary  induce  similar  cur- 
rents in  the  secondary  coil,  thus  affording  a  means 
of  "coupling"  two  circuits  together  magnetically. 
In  our  diagrams  the  primary  coil  (PRI)  is  shown 
with  fewer  turns  than  the  secondary  and  is  shown 
on  the  end  opposite  to  the  grid  connection  (G). 
The  other  connections  are  the  filament  (F),  the 
plate  connection  (P),  the  positive  "B"  battery 
connection  (B)  and  the  neutral  tap  (N)  used  for 
certain  neutralized  circuits.  The  abbreviation  is 
(RFT),  and  it  may  be  tuned  or  untuned,  the 
former  by  a  variable  condenser. 

4.  VARIOMETER.  This  is  a  form  of  variable 
inductance  used  in  place  of  the  air  core  choke,  and 
consists  of  a  movable  member  (The  Rotor)  which 
turns  inside  of  a  stationary  coil  called  the  "Stator." 
The  abbreviation  is  (VAR).  By  this  means  the 
inductive  or  choke  effect  can  be  varied  through  a 
wide  range  without  condensers  and  the  device  is 
frequently  used  for  tuning  a  circuit  inductively.  It 
may  be  tapped  at  the  mid-point  as  shown  at  (Q). 

5.  ANTENNA-GROUND-ARRESTOR.  At 
the  right  is  shown  the  symbol  for  the  antenna  or 
aerial,  abbreviation  (ANT).  In  the  center  is  the 
symbol  for  a  ground  connection  (GND),  and  at 
the  right  is  the  convention  for  a  lightning  arrestor 
(LA). 

6.  OUTPUT  -  PHONES  -  SPEAKER.  The 
symbol  for  the  headset  or  phones  is  shown  at  the 


left,  which  may  indicate  the  output  of  any  radio 
receiving  circuit.  Abbreviation  (PH).  The  polari- 
ty may  be  marked  by  (+)  or  minus  as  shown, 
or  this  may  be  omitted  at  will.  The  positive  con- 
nection of  the  phone  cords  is  colored  red  and  this 
red  strand  should  be  connected  to  the  (  +)  connec- 
tion of  the  circuit.  At  the  right  is  the  symbol  for 
the  horn  or  loud  speaker  which  can  also  be  marked 
with  the  polarity. 

7.  CONDENSERS.  A  "fixed"  condenser  con- 
sists of  alternate  sheets  of  tinfoil  and  paper  or  mica 
compressed  into  a  compact  pile,  and  adds 
"capacity"  to  the  circuit,  an  effect  opposite  to 
that  of  an  inductance  coil.  The  symbol  for  a  fixed 
condenser  is  at  the  left  where  the  abbreviation  is 
shown  as  (K)  and  where  the  capacity  in  micro- 
farads is  also  added  where  advisable.  A  VARI- 
ABLE CONDENSER  used  for  tuning  inductances 

i  s  shown  at  the  right,  where  the  rotor  plates  are 
i  ndicated  by  the  curved  line  and  the  stationary  or 
stator  plates  are  shown  by  the  short  straight  line. 
The  Stator  (Straight  line)  should  go  to  the  grid  of  a 
tube,  while  the  rotor  is  connected  to  the  ground 
side  or  ( — A)  side  of  the  circuit.  This  condenser 
is  also  rated  in  microfarads  (m.  f.). 

8.  RESISTANCES— RHEOSTATS.  A  fixed 
or  unvarying  resistance  is  shown  by  the  zig-zag 
line  which  distinguishes  it  from  an  inductance.  For 
low  resistances  used  for  controlling  the  filaments  of 
the  tubes,  its  magnitude  is  given  in  terms  of  ohms. 
For  very  high  resistances,  as  used  for  grid  leaks, 
the  resistance  is  given  in  terms  of  MEGOHMS, 
abbreviated   (MEG). 

A  RHEOSTAT  or  variable  resistance  is  shown 
at  the  right  and  is  usually  employed  for  controlling 
the  filament  current  of  tubes.  The  letter  (R)  is  used 
for  a  rheostat,  or  resistance. 

9.  BATTERIES.  An  "A"  or  filament  battery 
or  a  "C"  battery  is  shown  by  the  symbol  at  the  left 
which  consists  of  alternate  short  heavy  lines  and 
longer  light  lines.  The  short  heavy  lines  indicate 
the  negative  (  — )  plates  while  the  long  lines  are  the 
positive  plates  (  +).  Each  pair  of  these  lines  rep- 
resents one  cell,  and  it  is  the  best  practice  to  mark 
the  voltage  below  it  as  at  (6v.)  and  the  letter  (A), 
(B)  or  (C)  above  it  to  designate  the  type  of  battery. 
A  "B"  battery  is  at  the  right  where  the  dotted  line 
indicates  a  number  of  omitted  cells,  there  being 
too  many  cells  in  a  "B"  battery  tx>draw  them  com- 
plete. When  the  battery  is  tapped  at  some  low 
voltage,  as  at  (+22),  the  voltage  of  the  tap  is 
marked  in  this  way. 

10.  POTENTIOMETER.  This  is  a  device  which 
looks  much  like  a  rheostat  used  for  the  accurate 
control  of  voltages,  generally  the  biasing  voltages 
applied  to  the  grid  of  a  vacuum  tube.  It  consists 
of  a  fixed  resistance  of  from  200  to  400  ohms  con- 
nected across  the  battery  and  a  sliding  contact 
which  taps  off  the  drop  of  potential  at  any  point  of 
the   resistance.      The   polarity   of  the   slider   also 

{Turn  to  page  38) 


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38 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


(  Continued  from  page  35) 

varies  with  its  position,  becoming  negative  at  one 
end  and  positive  at  the  other. 

11.  THREE  ELEMENT  VACUUM  TUBES. 
The  three  elements  of  a  vacuum  tube  are  the 
filament  (F),  the  grid  (G)  and  the  plate  (P),  al- 
though these  parts  need  not  be  marked  as  shown. 
A  "hard"  amplifying  tube  is  indicated  by  a  single 
heavy  circle  drawn  around  the  elements  and  as  a 
hard  tube  is  much  used  at  present  for  a  detector  as 
well  as  for  an  amplifier.  When  a  soft  detector  tube 
must  be  used,  two  circles  are  used,  as  at  the  right. 
The  word  amplifier  is  abbreviated  (AMPL)  and 
detector  by  (DET). 

12.  TWO  AND  FOUR  ELEMENT  TUBES.  A 
two  element  tube  or  Fleming  valve  is  indicated  at 
the  right  and  has  the  filament  and  plate  but  no  grid. 
This  is  most  generally  used  as  a  rectifier  for  charg- 
ing storage  batteries  from  alternating  current,  but 
is  also  used  as  a  detector.  The  four  element  tube 
at  the  right  has  two  grids. 

13.  GRID  CONDENSER  AND  LEAK.  This 
symbol  used  with  detector  tubes  is  simply  a  combi- 
nation of  the  symbol  of  a  condenser  and  that  of  a 
resistance  (The  leak).  The  leak  abbreviation  is 
(GL)  and  the  grid  condenser  is  (GC).  If  either  of 
these  items  is  variable,  then  this  fact  is  indicated  by 
drawing  a  slanting  arrow  across  it  as  at  the  right. 

14.  CRYSTAL  DETECTOR.  A  crystal  detec- 
tor is  indicated  by  an  arrow  head  for  the  cat- 
whisker  and  a  small  block  for  the  crystal. 
Abbreviation  is  (CD). 

15.  AUDIO  (IRON  CORE)  TRANSFORMER. 
An  iron  core  transformer,  commonly  known  as  an 
audio  frequency  transformer,  is  used  for  increasing 
the  voltages  of  currents  approximating  voice  fre- 
quencies^or  audible  frequencies.  It  consists  of  a 
primary  winding  (PRI)  and  a  secondary  winding 
(SEC)  with  a  few  parallel  lines  drawn  between  the 
coils  to  indicate  the  iron  core.  The  four  connec- 
tions are  marked  as  follows:  (G)  for  grid,  (P)  for 
plate,  (F)  forjfilament  and  (B)  for  "B"  battery 
connections.  These  apply  to  vacuum  tube  connec- 
tions with  which  the  transformer  is  most  commonly 
used.  Iron  core  transformers  of  a  special  type  are 
also  sometimes  used  on  radio  frequencies,  but  when 
this  is  the  case  the  fact  will  be  particularly  noted  on 
the  drawing.    Abbr.  is  (AFT). 

16.  WIRING  AND  CONNECTIONS.  In 
general,  wiring  is  indicated  by  very  heavy  lines, 
and  curved  by  an  arc  where  a  turn  is  made.  Where 
two  wires  connect,  a  small  OPEN  circle  is  used  to 
mark  the  connection  as  at  (a).  Where  one  wire 
crosses  over  another,  the  crows-over  is  shown  as  at 
(b).  Connection  posts  or  terminals  for  batteries, 
etc.,  are  shown  by  a  circle  with  a  heavy  black  dot 
inside,  as  shown  in  a  horizontal  row.  The  letters 
indicating  the  "A",  "B",  and  "C"  batteries  are 
marked  at  the  terminals,  together  with  their 
polarities.  In  the  case  of  the  "B"  battery  connec- 
tions the  various  taps  are  marked  by  the  voltages 
as  at  (+22),  (+45)  and  (+90),  but  the  letter  "B" 
is  not  used. 

17.  TAP  SWITCHES.  FTap  switches  used  for 
cutting  out  active  turns  in  a  coil  should  be  con- 
nected so  that  the  contact  points  go  to  the  grid  or 
aerial  side  of  the  circuit  with  the  hinge  connected 
to  ground  or  on  the  far  side  from  the  grid  connec- 
tion to  prevent  body  capacity  effect. 

18.  INSTRUMENTS.  Measuring  instruments 
such  as  the  voltmeter  (VM),  the  ammetei  (AM)  or 
the  hot  wire  ammeter  (HWA)  are  shown  in  circles. 
The  polarity  should  be  marked,  and  also  the  range 
of  volts  or  amperes  at  at  (0 — 10)  and  (0—5). 

19.  JACKS.  Jacks  are  specially  arranged  con- 
tacts used  for  making  temporary  connections  by 
means  of  plugs  and  may  be  of  many  types.  At  the 
left  is  shown  the  single  circuit  jack  (J2)  generally 
used  for  the  last  stage  connection  and  at  the  left 
is  a  two  circuit  jack  (Jl)  used  for  plugging  in 
between  stages.  These  are  by  far  the  most  common 
types. 

20.  SWITCHES.  Different  types  of  battery 
switches  are  shown,  the  left  symbol  being  for 
symbolic  diagrams  while  the  second  from  the  left  is 
used  frequently  on  picture  diagrams.  The  switch 
at  the  right  is  a  double  pole  knife  switch  used  for 
heavy  currents. 

Sample  Symbolic  Drawings 

ON  SHEET  No.  2  we  show  four  repre- 
sentative circuit  drawings  which 
include  most  of  the  symbols  tabulated. 
Each  symbol  is  lettered  with  the  standard 
abbreviation  so  that  it  will  not  be  difficult 
to  trace  out  the  relation  between  the 
parts  in  the  table  and  the  corresponding 
parts   in   the   diagram. 

A  simple  crystal  detector  set,  tuned  by 
the  variometer  (VAR)  is  shown  in  Fig. 
21.  Here  we  have  the  symbols  for  the 
variometer,  crystal,  aerial,  ground, 
phones  and  two  fixed  condensers.  Note 
that  when  two  condensors  are  shown 
that  they  are  numbered  as  at  (Kl)  and 
(K2).  In  Fig  22  we  have  another  single 
circuit  crystal  set  tuned  by  a  simple 
tapped   inductance    (L),   the   tap   switch 


(SW)  being  used  to  vary  the  number  of 
turns  in  circuit. 

f*  In  Fig.  23  is  a  regenerative  circuit  with 
one  stage  of  audio  frequency  amplifica- 
tion, a  type  of  circuit,  very  commonly 
met  with.  The  detector  tube  (Tl)  is  a 
soft  tube,  while  the  amplifier  tube  (T2) 
is  a  hard  tube,  as  will  be  seen  from  the 
circles.  A  coupler  is  used  for  tuning, 
having  the  primary  coil  (LI)  and  the 
secondary  coil  (L2),  this  being  used 
sometimes  instead  of  the  abbreviations 
"PRI"  and  "SEC."  The  secondary  is 
tuned  by  the  variable  condensor  (Kl). 
For  regeneration  we  have  the  tickler  coil 
(TIC)  placed  directly  above  the  second- 
ary coil  (L2)  and  connected  with  it  by 
means  of  an  arrow.  The  arrow  in  this 
case  indicates  that  the  two  coils  are 
inductively  coupled  by  a  variable  rela- 
tion; that  is,  that  the  position  of  (TIC) 
can  be  varied  in  respect  to  (L2).  The 
grid  condensor  (GC)  and  the  grid  leak 
(GL)  are  shown  connected  to  the  grid 
of  the  tube. 

Current  for  lighting  the  tube  fila- 
ments is  supplied  by  the  six  volt  "A" 
battery  which  is  connected  so  that  the 
negative  pole  goes  to  the  detector  rheo- 
stat (Rl).  The  negative  pole  of  the 
"A"  battery  connects  with  the  negative 
pole  of  the  "B"  battery,  and  the  latter 
is  tapped  at  the  (  +  22)  volt  point  for  the 
detector  current.  The  total  voltage  of 
the  "B"  battery  at  (+90)  goes  to  the 
last  stage  jack  (J2).  A  two  circuit  jack 
(Jl)  permits  us  to  plug  in  on  the  detec- 
tor tube  alone  without  amplification,  or 
without  lighting  the  amplifier  tube 
(T2).  Plugged  in  on  (J2)  we  get  the 
amplified  or  intensified  current  for  the 
operation  of  a  loud  speaker. 

An  iron  core  audio  frequency  trans- 
former (AFT)  transfers  the  plate  energy 
of  the  detector  tube  (Tl)  to  the  amplifier 
tube  (T2),  and  it  will  be  noted  that  the 
terminals  of  the  transformer  are  marked 
in  accordance  with  the  points  that  they 
connect.  Thus  (G)  goes  to  the  grid  of 
(T2),  connection  (P)  goes  to  the  plate  of 
tube  (Tl),  connection  (B)  goes  to  the 
(  +  22)  volt  tap  of  the  "B"  battery,  and 
connection  (F)  goes  to  the  ( — A)  through 
the  "C"  battery.  A  fixed  condenser  (K) 
is  shunted  across  the  secondary.  A  4.5 
volt  "C"  battery  is  used  for  biasing  the 
grid  of  the  tube  (T2)  and  the  negative 
pole  ( — )  is  connected  to  (F)  of  the  trans- 
former so  that  the  current  gets  to  the 
grid  of  the  tube  through  the  windings. 
Tube  (T2)  is  controlled  by  rheostat 
(R2). 

Fig.  24  is  a  typical  reflex  circuit  with 
the  radio  frequency  transformer  (RFT) 
and  the  audio  frequency  transformer 
(AFT),  the  former  being  tuned  by  the 
variable  condenser  (K2).  A  coupler  is 
provided  with  the  primary  (LI)  and 
secondary  (L2)  by  which  the  set  is  tuned 
to  wavelength.  The  grid  bias  on  the 
tube  is  varied  by  the  potentiometer  (PO). 
The  rest  of  the  parts  have  been  explained 
before. 


Crystal  Detector  Sets 

TO  ME,  the  crystal  set  has  always 
seemed  the  most  wonderful  of  all 
radio  receivers,  for  with  this  device 
we  employ  the  feeble  energy  of  the  radio 
waves  alone  to  vibrate  the  diaphragms 
of  the  phones  without  aid  or  reinforce- 
ment from  local  sources  of  energy.  After 
traveling  "fifty  miles  or  so,  there  is  still 
sufficient  energy  left  in  the  waves  to 
move  a  relatively  stiff  piece  of  metal  and 
to  produce  the  audible  air  vibrations 
known  as  sound.  Further,  it  is  an  exhi- 
bition of  the  remarkable  sensitivity  of 
the     modern     headset     which     produces 


understandable  signals  on  so  small  a*n 
amount  of  current  that  it  can  be  esti- 
mated in  millionths  of  an  ampere;  and 
yet,  with  all  of  this  delicacy,  the  appara- 
tus is  perfectly  simple  and  so  rugged 
that  it  can  withstand  a  considerable 
amount  of  abuse  at  the  hands  of  the 
listener. 

To  most  of  our  readers  who  have  had 
experience  only  with  the  cheap  and  simple 
single-slide,  single-circuit  crystal  detec- 
tor sets  sold  on  the  open  .market,  the 
crystal  detector  is  considered  only  in  the 
light  of  a  toy  having  only  a  very  limited 
use  in  reception.  This,  however,  is  not 
the  case,  for  with  proper  attention  to  the 
details  of  construction  and  with  as  much 
care  taken  with  the  tuning  units  as  we 
pay  to  the  construction  of  a  tube  set,  the 
performance  can  be  greatly  improved  in 
regard  to  distance  range  and  signal 
strength.  If  we  constructed  our  tube 
sets  with  the  same  lack  of  care  and  with 
the  same  primitive  tuning  systems  that 
are  used  on  commercial  crystal  sets,  we 
would  not  get  very  much  better  perform- 
ance*. Single-slider,  single-circuit  tuners 
are  not  conducive  of  good  results  with 
either  the  crystal  or  tube  detector,  for 
they  cannot  be  tuned  accurately  in  re- 
sonance with  the  incoming  waves,  and 
there  is  always  a  considerable  loss  taking 
place  that  limits  the  distance  and 
volume. 

The  Crystal  Detector  Circuit 

OUR  primitive  crystal  detector  circuit 
consists  of  three  principal  units: 
(1)  The  tuning  unit,  by  which  it  is 
brought  into  resonance  with  the  incoming 
waves,  (2)  The  crystal  detector  employed 
for  rectifying  the  radio  frequency  im- 
pulses for  the  development  of  the  audio 
waves,  and  (3)  The  audio  output  mechan- 
ism which  converts  the  audio  frequency 
electrical  waves  into  mechanical'  sound 
vibrations  (Phones).  All  three  elements 
must  be  as  perfect  as  possible  if  we  are  to 
extract  the  maximum  output  in  the  form 
of  sound,  for  the  incoming  energy  is 
exceedingly  feeble  and  must  be  carefully 
utilized  with  the  least  possible  loss. 
This  means  sharp  tuning,  a  crystal  hav- 
ing excellent  rectifying  qualities  and  an 
exceedingly  sensitive  pair  of  phones, 
none  of  which  are  in  evidence  in  the  usual 
$2.00  crystal  detector  set.  In  reviewing 
the  requirements,  we  must  also  remember 
to  include  an  efficient  antenna  into  the 
assembly,  which  should  have  greater 
length  and  capacity  than  the  antenna 
commonly  used  with  tube  sets.  The 
latter  item  is  generally  neglected  in  the 
installation  of  a  crystal  set,  with  the 
result  that  very  little  volume  or  distance 
is  had.  Conservation  of  energy  is  a  prime 
requisite. 

It  is  here  that  the  low-loss  coil  and  the 
low-loss  condenser  hold  forth  with 
particular  advantage;  spiderweb,  honey- 
comb or  barrel-wound  coils  being  of 
great  advantage  in  the  construction  of 
such  a  set.  The  phones  should  prefer- 
ably be  of  the  mica  diaphragm  class  or 
with  very  thin  flexible  metal  diaphragms 
so  that  the  slightest  current  in  the  coils 
will  give  a  maximum  vibration.  When 
we  look  at  the  cheap  phones  ordinarily 
supplied  with  crystal  sets,  with  their 
thick  cast-iron  diaphragms  and  their 
weak  magnets,  it  is  no  wonder  that 
reception  is  limited  to  10  or  15  miles. 
This  would  be  almost  the  case  with  a 
tube  set  if  it  were  supplied  with  the  same 
sort  of  phones.  The  feeble  impulses 
received  demand  the  most  sensitive  and 
efficient  equipment  that  we  can  supply 
if  the  crystal  set  is  to  be  more  than  a 
mere  toy  for  children's  use. 

Please   don't   infer   that    I   am   recom- 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


39 


mending  the  crystal  set  as  a  substitute 
for  the  tube  set,  for  I  am  not.  I  am 
simply  bringing  to  your  attention  the 
fact  that  the  crystal  set  performance  can 
be  wonderfully  improved  by  a  little  care 
in  the  construction  and  that  it  is  a  most 
desirable  proposition  for  local  reception 
where  we  do  not  wish  to  go  to  the  trouble 
of  installing  batteries  and  similar  com- 
plications. The  crystal  set  has  a  field 
all  its  own  and  is  almost  indispensable 
for  certain  purposes,  and  for  this  reason 
I  believe  that  more  attention  should  be 
paid  to  the  development  of  its  perform- 
ance rather  than  to  cutting  down  on  the 
expense  of  construction,  as  has  been  done 
heretofore.  You  cannot  get  long  distance 
consistently,  nor  can  you  get  full  loud 
speaker  volume  of  the  crystal  alone,  but 
you  can  get  locals  with  good  volume, 
clear  and  sweet,  without  the  fuss  attend- 
ing the  operation  of  a  tube  receiver. 

When  loud  speaker  volume  is  required 
on  local,  with  particular  attention  to 
quality,  we  can  add  one  or  more  stages 
of  audio  frequency  amplification  to  the 
detector.  Of  course,  we  are  now  getting 
back  to  vacuum  tube  complications  and 
batteries,  but  with  very  simple  layouts 
we  can  obtain  wonderful  tone  values  on 
the  loud  speaker  and  a  somewhat  in- 
creased distance.  Just  as  an  experi- 
ment, it  is  very  interesting  to  add  resist- 
ance coupled  stages  to  a  crystal  detector 
to  discover  what  real  tone  purity  is  like. 
The  natural  tone  and  life-like  quality 
will  be  a  revelation  to  you,  and  if  you 
live  within  25  miles  or  so  of  a  broad- 
casting station,  f  am  sure  that  you  will 
keep  this  circuit  hooked  up  permanently. 

Future  of  the  Crystal  Set 

CONSIDERING  the  many  5,000  watt 
broadcasting  stations  now  under 
construction,  and  the  increasing  practice 
of  re-broadcasting,  it  is  certain  that  the 
crystal  detector  receiver  will  find  a  more 
extended  use  than  has  been  the  case  in 
the  past.  Increased  power  at  the  stations 
and  the  relaying  of  these  stations  at  close 
intervals  over  the  country  will  mean  that 
the  crystal  will  take  on  a  new  life.  At 
least  ten  telephone  companies  have 
adopted  local  re-broadcasting  systems  as 
an  additional  service  to  their  subscribers, 
and  I  do  not  believe  that  the  telephone 
companies  will  be  the  only  people  to 
engage  in  this  work.  If  the  network  of 
re-broadcasting  stations  is  fully  developed 
the  use  of  the  crystal  set  will  be  practical 
in  almost  any  part  of  the  United  States. 
One  re-broadcast  station  equipped 
with  a  good  receiving  set  and  a  trans- 
mitter of  moderate  power  will  easily 
cover  a  radius  of  25  miles  and  will 
efficiently  serve  crystal  detectors  in  this 
50-mile  circle.  The  expense  of  main- 
taining such  a  station  is  comparatively 
small  and  can  be  borne  by  the  local 
Granges  or  community  associations  with 
a  great  saving  to  their  members.  The 
station  receives  the  voice  and  music 
from  distant  stations  and  then  broad- 
casts these  signals  through  simple  appa- 
ratus to  local  listeners,  thus  avoiding  the 
expense  and  trouble  of  arranging  pro- 
grams. So  far,  this  arrangement  has 
increased  the  total  number  of  listeners 
tremendously  without  appreciably  affect- 
ing the  sale  of  tube  sets.  On  the  contrary, 
one  re-broadcasting  station  states  that 
the  interest  aroused  in  radio  via  crystal 
sets  has  greatly  increased  the  sale  of  tube 
sets  in  its  territory,  and  that  a  great 
proportion  of  the  listeners  now  have 
both  crystal  and  tube  sets  in  their 
homes.  Tiring  of  the  local  re-broadcasts, 
and  desiring  different  programs,  they 
turn  to  their  tube  sets  and  tune  in  the 
distant  stations  for  themselves. 


While  the  complete  theory  of  contact 
rectification  is  not  yet  well  understood, 
I  will  explain  the  functioning  and  purpose 
of  the  crystal  in  a  general  way  so  that 
the  beginner  can  at  least  get  a  working 
knowledge  of  its  properties  when  in- 
stalled in  the  receiving  set.  Mechani- 
cally it  is  very  simple,  consisting  of  a 
small  piece  of  mineral  called  the  crystal, 
and  a  thin  wire  making  light  contact 
with  the  crystal  at  a  sensitive  spot.  In 
some  cases,  contact  is  had  between  two 
crystals  instead  of  between  the  wire 
and  crystal,  but  in  any  event  the  radio 
frequency  current  must  pass  through  a 
high  resistance  contact  of  some  sort 
before  passing  through  the  phones,  so 
that  the  audio  or  "hearable"  portion  of 
the  incoming  waves  can  be  developed. 

Owing  to  the  rapidity  with  which  the 
radio  wave  oscillates  back  and  forth,  the 
diagrams  of  the  phones  cannot  follow  the 
radio   frequency  currents  in  the  receiver 


A  ROUND-UP  OF 
HOOK-UPS 

in  the  Deluxe  AUGUST    IS- 
SUE OF  RADIO  AGE. 

Never  before  have  you  seen  such 
a  galaxy  of  hookups,  from  the 
simplest  though  efficient  crystal  to 
the  most  recent  simplified  super- 
heterodyne receivers.  Radio  from 
its  humble  beginning  to  its  present 
peaks  of  achievement  in  the  Special 
Summer  Number  of  RADIO  AGE. 

All  basic  Hookups. 

THIRTY  PAGES  OF  DE- 
LUXE BLUEPRINTS. 

Order  your  Copy  in  Advance. 

$2.50  a  year. 

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directly  and  nothing  will  be  heard  in  the 
phones  if  some  sort  of  rectifier  or  "de- 
tector" is  not  inserted  into  the  circuit. 
These  waves  are  "alternating,"  that  is, 
they  flow  first  in  one  direction  and  then 
in  the  other,  and  before  we  hear  the  sig- 
nals these  waves  must  be  made  "uni- 
directional" so  that  they  will  flow  in  one 
direction  through  the  phones  but  with 
an  intensity  that  varies  according  to  the 
sounds  sent  out  by  the  broadcasting 
station.  The  crystal  detector  with  its 
contacting  "catwhisker"  wire  acts  as 
such  a  rectifier  and  permits  the  passage 
of  only  one  set  of  waves  that  are  flowing 
in  the  same  direction. 

With  the  radio  frequency  current  rec- 
tified, the  "audio  frequency"  waves  are 
developed  so  that  the  diaphragms  of  the 
phones  follow  the  slower  voice  frequency 
pulsations,  thus  producing  sound.  Our 
station  waves  therefore  consist  of  two 
components,  the  high  radio  frequency 
carrier  waves  oscillating  at  the  rate  of 
about  1,000,000  vibrations  per  second, 
and  the  audio  frequency  waves  impressed 
on  them  that  will  range  from  a  few  hun- 
dred to  an  upper  limit  of  about  15,000 
vibrations  per  second.  These  latter 
waves  are  produced  by  varying  the  in- 
tensity of  the  radio  waves  by  "modula- 
tion," and  are  not  actually  an  indepen- 
dent series. 

There  are  a  great  number  of  minerals 
that  will  act  as  detectors  to  some  extent, 
but  only  a  few  that  are  effective  enough 
to  be  used  in   the  practical  crystal  set. 


Galena,  silicon,  carborundum,  cerusite, 
pyrites,  perikon,  radiocite,  and  hecite  are 
among  the  most  commonly  used  simple 
minerals,  and  in  addition  to  these  are  the 
numerous  synthetic  crystals  that  bear  a 
multitude  of  trade  names.  A  good  galena 
crystal  is  probably  one  of  the  most  sensi- 
tive crystals,  but  it  is  not  stable  and  must 
be  readjusted  frequently.  Silicon  and 
carborundum  do  not  require  so  frequent 
adjustment  and  are  quite  sensitive  if 
carefully  selected  and  mounted.  The 
synthetic  crystals  are  in  most  cases  stable 
and  sensitive,  and  have  the  advantage  of 
having  a  greater  effective  area  or  more 
"hot  spots"  than  the  natural  crystals,  so 
that  it  is  not  so  difficult  to  adjust  them. 

For  the  catswhisker  wire,  we  require 
a  metal  that  will  not  corrode  under 
ordinary  atmospheric  conditions  and  one 
that  will  maintain  a  bright  metallic  con- 
.tact  area  at  the  point  where  it  rests  on  the 
crystal.  A  copper  wire  will  work  well 
with  most  crystals,  but  a  silver  or  gold 
wire  is  better,  as  it  does  not  corrode  or 
get  dull  as  rapidly.  With  the  exception 
of  the  carborundum  crystal,  the  cat- 
whisker  wire  should  make  very  light 
contact  with  the  crystal,  working  best 
when  only  just  barely  touching  the  sur- 
face. With  the  carborundum  detector  a 
very  heavy  pressure  is  required,  which 
in  itself  is  one  reason  for  the  stability  of 
the  carborundum,  as  the  heavy  pressure 
prevents  the  displacement  of  the  contact 
when  subjected  to  vibration. 

There  has  been  a  great  deal  of  argu- 
ment for  and  against  the  fixed  crystal 
detector  with  the  immovable  catwhisker, 
but  I  believe  that  the  fixed  detector  will 
prove  best  in  the  long  run  for  the  begin- 
ner, at  least,  as  it  avoids  the  necessity  of 
constant  readjustment  and  the  detuning 
effect  when  these  adjustments  are  made. 
It  will  perhaps  be  of  interest  to  know  that 
the  crystal  has  a  great  deal  of  effect  in 
the  tuning  of  the  circuit  and  very  often 
we  can  tune  a  station  in  and  out  by  means 
of  the  crystal  adjustment  alone.  For  the 
experienced  crystal  set  operator,  the 
adjustable  crystal  is  therefore  often  an 
advantage,  as  it  is  an  aid  to  selectivity 
and  tuning,  particularly  where  there  are 
many  strong  local  stations  and  other 
interferences. 

It  is  a  good  plan  to  get  a  number  of 
crystals  and  then  select  the  best  crystal 
by  actual  test.  There  is  a  great  deal  of 
variation  among  crystals  even  of  the  same 
make,  and  the  only  way  that  you  can  be 
assured  of  the  maximum  results  is  to 
select  the  best  crystal  from  a  number  of 
samples. 

The  Hook-Up  or  Circuit 

THERE  are  about  a  thousand  different 
crystal  detector  hook-ups  from  which 
to  make  a  choice,  and  all  of  them  have 
their  adherents,  who  believe  that  they 
have  the  only  circuit  worth  using.  Some 
employ  variometers  for  tuning  induct- 
ances, others  use  spiderweb  coils,  vario- 
couplers,  honeycomb  coils  and  straight 
solenoid  coils  in  all  sort  of  combinations, 
but  as  a  matter  of  fact,  a  close  examina- 
tion will  show  that  most  of  these  circuits 
can  be  boiled  down  to  six  distinct  classes. 
The  type  of  inductance  does  not  change 
the  characteristics  of  a  circuit  as  a  circuit; 
it  simply  adds  or  detracts  from  its  effi- 
ciency by  the  sharpness  of  its  tuning 
properties  and  the  losses  occuring  within 
the  coil.  A  variometer  may  show  better 
results  than  a  simple  tuning  coil,  simply 
for  the  reason  that  it  can  be  more  closely 
adjusted  to  wavelength  than  the  coil — ■ 
not  because  it  is  a  variometer.  An  in- 
ductance is  an  inductance  no  matter  what 
form  it  may  be  used. 

(Turn  to  page  42) 


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K-  WATER  OR 

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42 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


(Continued  from  page  39) 

Fig.  1  shows  the  six  basic  circuits  with 
their  relative  audibility  value,  as  de- 
termined by  the  U.  S.  Bureau  of  Stan- 
dards. The  relative  signal  strengths  are 
given  in  terms  of  percentages,  and  it  will 
be  seen  that  the  hook-up  has  a  great  deal 
to  do  with  the  reception,  varying  as  it 
does  from  10  per  cent  to  85  per  cent. 
These  diagrams  refer  only  to  the  detector 
circuit  itself  and  do  not  consider  the 
various  methods  of  coupling  or  connect- 
ing the  circuit  to  the  aerial  and  ground. 
A  variable  condenser  is  used  for  tuning 
a  fixed  inductance  in  all  cases. 

Diagram  (A)  shows  a  simple  form  of 
circuit  often  used,  which  contains  the 
inductance  (L),  the  variable  condenser 
(C),  the  crystal  detector  (CD)  and  the 
phones  (Ph)  all  connected  in  series.  For 
ordinary  broadcasting  vavelengths  there 
will  be  about  55  turns  of  wire  in  (L)  when 
wound  on  a  three  inch  tube,  and  the  ca- 
pacity of  the  variable  condenser  (C)  will 
be  from  0.00035  m.f.  to  0.0005  m.f.  The 
audibility  is  55  per  cent. 

In  Diagram  (6)  we  have  the  same  cir- 
cuit with  the  addition  of  the  small  fixed 
condenser  (K)  connected  across  the  cry- 
stal detector.  This  fixed  condenser  acts 
as  a  storage  capacity  for  the  waves  and 
adds  considerably  to  the  volume,  as  it 
supplies  an  additional  current  to  the 
crystal.  This  addition  has  increased  the 
audibility  from  55  per  cent  to  85  per  cent, 
the  maximum  value  determined  by  the 
Bureau. 

The  capacity  of  (K)  depends  upon  the 
nature  of  the  crystal  detector,  but  in  any 
event  the  capacity  must  be  small  to 
prevent  by-passing  much  of  the  current 
across  the  dectector.  .With  some  de- 
tectors 0.00025  m.  f.  is  about  right, 
while  with  other  types  this  may  be  as 
low  as  0.0001  m.f.  or  even  less.  A  small 
three-plate  variable  condenser  will  often 
prove  of  value  in  getting  the  adjust- 
ment correctly. 

In  Diagram  (C)  we  have  the  same  cir- 
cuit as  in  Diagram  (A),  but  a  fixed  con- 
denser (K)  is  used  to  bypass  radio  fre- 
quency current  around  the  phones.  The 
average  audibility  under  all  conditions 
is  reduced  to  45  per  cent ;  hence,  this  is  not 
always  an  advisable  addition.  In  many 
makes  of  phones  there  is  a  considerable 
amount  of  distributed  capacity  in  the 
windings  of  the  magnets  and  this  fre- 
quently is  sufficient  to  properly  by-pass 
the  radio  frequency  current  around  the 
inductance  without  the  addition  of  ex- 
ternal capacity.  However,  in  case  the 
phones  have  a  high  inductive  value  with 
little  distributed  capacity,  a  by-pass  (K) 
may  be  necessary. 

Diagram  (D)  is  a  type  of  crystal  de- 
tector circuit  often  used  on  wave-meters 
and  similar  instruments  where  very  sharp 
tuning  is  necessary.  The  audibility  is  so 
low  (10  per  cent)  that  it  is  impracticable 
for  a  receiver  and  therefore  need  not  be 
discussed  further.  Its  only  virtue  is  its 
extreme    selectivity. 

Diagram  (E)  a  second  variable  con- 
denser (C2)  is  employed  in  addition  to 
the  original  variable  condenser  (CI). 
This  sharpens  the  tuning  considerably 
and  has  a  much  greater  audibility  than 
the  circuit  in  Diagram  (D).  The  audi- 
bility is  four  times  as  great  as  with  (D) 
and  is  almost  equal  to  that  of  the  first 
diagram. 

Our  last  diagram  (F)  is  the  ultimate  in 
selectivity  but  has  a  very  low  audibility 
factor.  The  circuit  is  split  by  means  of 
the  coupler  coils  (L2)  and  (L3)  so  that 
almost  any  degree  of  selectivity  can  be 
attained  but  at  the  expense  of  a  great 
loss  in   signal  strength.     We  can   obtain 


a  good  degree  of  selectivity  by  other 
means  and  without  so  much  loss  in  signal 
strength;  hence,  this  type  or  circuit  can  be 
neglected  for  the  time  being. 

Circuit  With  Coupler 

FOR  the  sake  of  selectivity  we  will  con- 
nect our  aerial  and  ground  to  the 
detector  circuit  by  means  of  an  aperiodic 
or  semi-aperiodic  coupler  of  the  type  so 
commonly  use  in  tube  sets.  For  the  de- 
tector circuit  we  will  adopt  the  circuit 
shown  in  Diagram  (B)  to  obtain  the 
greatest  signal  strength  and  will  depend 
entirely  upon  the  coupler  construction 
for  our  selectivity  and  tuning.  This 
combination  will  probably  give  us  the 
best  all-round  combination  for  signal 
strength  and  selectivity  and  at  the  same 
time  is  simple  to  build  and  tune. 

In  Fig.  2  we  have  the  schematic  dia- 
gram of  the  complete  circuit.  The 
coupler  consists  of  the  primary  coil  (LI) 
connected  at  one  end  to  the  aerial  and 
to  the  ground  at  the  other  end.  The  radio 
impulses  from  (LI)  are  communicated  to 
the  secondary  coil  (L2)  which  is  identical 
with  the  coil  (L)  in  Diagram  (B).  A 
variable  condenser  (CI)  is  connected 
across  the  secondary  coil  so  that  it  can  be 
tuned  to  wavelength.  The  fixed  con- 
denser (K)  connected  across  the  crystal 
detector  (CD)  serves  the  purpose  al- 
ready described.  The  phones  (Ph)  are 
in  series  with  the  crystal  detector. 

By  means  of  the  inductively  coupled 
coils  (LI)  and  (L2)  we  can  obtain  much 
better  selectivity  than  with  the  aerial  and 
ground  connected  directly  to  the  de- 
tector circuit.  The  selectivity  depends 
largely  upon  the  distance  between  these 
two  coils.  The  greater  the  distance  the 
greater  will  be  the  tuning  qualities  where 
there  are  many  strong  local  stations. 
Properly  adjusted,  it  is  possible  to  tune 
in  and  out  on  a  difference  of  five  meters 
wavelength,  but  with  comparatively  lit- 
tle loss  in  signal  strength.  With  the 
aerial  and  ground  connected  directly  to 
the  detector  circuit,  it  is  probable  that  a 
nearby  station  will  come  in  all  around 
the  dial,  no  matter  how  it  may  be  turned. 

In  regard  to  a  crystal  detector,  it  may 
be  said  that  it  is  much  more  difficult  to 
get  selectivity  with  a  crystal  than  with 
a  tube  receiver  and  that  greater  care  will 
be  required  in  the  adjustment.  The 
crystal  has  the  peculiar  property  of  hang- 
ing on  to  a  station  even  against  powerful 
controls,  and  while  it  has  not  much  dis- 
tance or  ability  on  weaksignals.it  will  hold 
onlike!grimideathto|fairly  strong  signals. 

Under  some  conditions  it  may  be  ad- 
visable to  connect  the  lower  part  of  the 
circuit  to  the  ground  connection  (GND) 
by  means  of  the  short  dotted  wire  (g). 
The  rotary  plates  should  also  go  to  this 
side  of  the  circuit  (ground)  as  indicated 
by  the  curved  line  at  (CI)  and  the 
stationary  plates  are  connected  directly 
to  the  crystal  detector  (CD). 

With  some  phones,  which  have  very 
little  distributed  capacity,  it  may  help 
matters  to  connect  the  fixed  condenser 
(Kl)  across  the  phones  (Ph)  as  indicated 
by  the  dotted  lines.  This  is  best  deter- 
mined by  actual  test,  after  the  set  has 
been  built  and  connected  up  to  the  aerial. 
This  may  be  a  0.001  m.f.  fixed  condenser. 

Picture  Diagram  of  Set 

A  complete  drawing  of  the  circuit  with 
all  of  the  parts  in  place  is  shown  by  Fig. 
3,  the  letters  in  this  drawing  correspond- 
ing with  similar  letters  in  the  schematic 
diagram  of  Fig.  2.  A  detail  view  of  the 
coupler  coil  is  shown  which  is  connected 
to  the  variable  tuning  condenser  (CI), 
the  latter  being  connected  directly  across 
the  secondary  coil  (L2)  of  the  tuning  in- 


ductance. The  crystal  detector  (CD)  is 
best  placed  as  shown  and  should  not 
be  mounted  on  the  front  panel  where  it  is 
likely  to  be  thrown  out  of  adjustment  by 
the  jar  of  the  hand  every  time  we  move 
the  tuning  dial. 

The  tuning  inductance  (L1-L2)  is 
wound  on  a  cardboard  tube  three  inches 
in  diameter  and  about  4  1-2  incles  long. 
The  primary  winding  consists  of  12  turns 
of  No.  24  D.C.C.  wire,  and  a  space  of 
about  1-2  inch  is  left  between  this  coil 
and  the  secondary  coil  (L2).  Starting 
coil  (L2),  we  wind  on  55  turns  of  the  same 
size  wire,  and  fasten  the  ends  of  the  coil 
securely  by  passing  them  through  holes 
punched  in  the  cardboard  tube.  For 
strong  local  stations,  it  may  be  necessary 
to  increase  the  distance  between  coils  to 
5-8  inch  or  3-4  inch  to  obtain  the  required 
selectivity,  but  this  space  should  be  no 
greater  than  actually  required  for  the 
complete  tuning  out  of  the  strongest 
station.  If  the  gap  is  much  greater  than 
this,  the  signal  strength  will  be  reduced. 
The  tentative  wire  (g)  and  the  experimen- 
tal fixed  condenser  (Kl)  are  shown  in 
dotted  lines  as  they  may  not  be  needed 
with  the  combination  of  parts  used  in 
your  set. 

The  condenser  (CI)  can  be  either  a  17 
plate  or  .23  plate  variable  condenser  hav- 
ing a  capacity  of  0.00035  m.m.  to  0.0005 
m.m.,  but  the  latter  is  preferable.  If  you 
do  not  wish  to  wind  the  coil  yourself,  you 
can  use  a  neutrodyne  transformer  which 
can  be  purchased  complete  and  mounted 
on  the  back  of  the  variable  condenser. 
Such  combinations  cover  a  wavelength 
band  of  from  200  to  600  meters,  the  range 
of  the  average  broadcasting  stations. 

It  is  most  convenient  to  mount  the 
apparatus  on  a  6  in.  x  7  in.  x3-16  in.  panel 
as  shown  by  Fig.  4  with  the  tuning  dial 
(D)  appearing  on  the  front  of  the  panel 
as  shown.  The  aerial  binding  post  is  at 
ANT,  the  ground  connecting  post  at 
GND,  and  the  phone  posts  at  PH.  The 
method  of  connecting  to  the  aerial  and 
ground  is  also  shown  in  this  view,  the 
ground  being  a  connection  to  a  water  or 
steam  pipe. 

The  aerial  should  not  be  less  than  60 
feet  in  length,  and  more  than  this  is 
desirable  where  the  necessary  room  can  be 
obtained.  With  a  crystal  detector  set, 
the  more  aerial  wire  that  we  hang  up,  the 
better  wili  be  our  reception,  and  any 
length  (L)  can  be  used  up  to  150  feet. 

With  two  wires  placed  side  by  side,  150 
feet  long  and  with  the  set  located  in  the 
open  country,  quite  long  distances  can  be 
covered.  However,  with  a  60  foot  aerial 
in  a  good  locality,  we  can  get  good  re- 
ception with  fair  distance,  providing  that 
the  aerial  is  not  screened  by  steel  struc- 
tures such  as  steel  factory  and  office 
buildings,  bridges,  etc. 


Higher  Power  Licensed 
To  Beat  Static 

THE  Department  of  Commerce  has 
announced  that  favorable  consider- 
ation will  be  given  to  applications  from 
owners  of  Class  B  broadcasting  stations 
for  permission  to  use  higher  power  with- 
out requiring  the  increases  to  be  made 
in  steps  of  500  watts  as  has  been  the 
practice  heretofore,  provided  the  sta- 
tions are  situated  outside  of  congested 
receiving    centers. 

In  taking  this  action  the  Department 
is  endeavoring  to  satisfy  the  demand 
of  broadcast  listeners  that  the  use  of 
increased  power  be  permitted  in  order 
to  overcome  the  existing  static  conditions 
which  are  making  reception  difficult. 


RADIO  AGE  for  July,  1925 


^%|3^ 


J?idc**,ULp« 

czrid  ___ 


The  Magazine  of  the  Hour  43 


'T*HE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers' 
-*■    contributed  by  our  readers.      It  is  a  department 


in  RADIO  AGE,  is 
;  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


IF  THE  filaments  of  your  vacuum 
tubes  begin  acting  as  you  feel 
during  the  Summer,  it  is  not  neces- 
sarily an  indication  that  their  span  of  life 
has  been  bridged,  for  rejuvenation  of 
tubes  seems  to  be  as  welcome  to  inani- 
mate thoriated  filaments  as  it  is  to  those 
who  have  sought  the  fountain  of  eternal 
youth. 

Tube  manufacturers  have  cautioned 
their  customers,  via  the  literature  ac- 
companying the  tubes  in  the  cartons, 
that  a  paralyzed  tube  may  be  restored 
to  its  pristine  activity  by  leaving  it 
lighted  in  the  set  for  ten  minutes  with 
the  "B"  battery  shut  off,  this  process 
apparently  bringing  the  thorium  from  the 
filament  center  and  giving  the  tube  new 
life. 

One  of  our  prominent  manufacturers 
has  come  forward  with  a  tube'rejuve- 
nator  on  which  radio  fandom's  interest 
seems  to  have  centered. 

It  consists  primarily  of  a  small  step- 
down  transformer,  similar  to  the  toy 
transformers  used  for  running  toy  rail- 
road trains,  etc.,  being  made  in  two 
types,  one  for  110-20  volt  primary  with 
ten,  four,  sixteen  and  eight  volt  second- 
ary sections,  and  the  other  for  the  220- 
230  volt  circuits  with  the  same  secondary 
outputs.  This,  together  with  a  socket 
for  each  size  of  tube,  comprises  the  layout, 
to  which  the  owner  adds  his  timepiece. 

For  the  UV  199  tubes  the  tube  is 
placed  in  the  socket  after  the  transformer 
has  been  plugged  into  the  lighting 
mains.  It  is  given  ten  volts  on  the  fila- 
ment for  30  seconds,  then  the  voltage 
is  cut  to  four  volts  and  the  tube  is  allowed 
to  remain  for  ten  minutes.  The  first 
voltage  is  known  as  the  shocking  charge 
and  serves  to  drive  the  thorium  from  the 
filament  center.  The  ten  minute  lighting 
of  the  filament  at  four  volts  is  known  as 
the  baking  charge  and  serves  to  solidify 
the  thorium  on  the  filament  so  its  elec- 
tronic emission  is  again  at  a  maximum. 

For  the  UV201-A  type  the  shocking 
voltage  is  sixteen  volts  for  a  period  of 
30  seconds,  and  a  baking  charge  at  eight 
volts  which  lasts  for  ten  minutes.  The 
same  action  takes  place  as  with  the  199. 


As 


One    Need    Remains 

a   result   the   owner   of   emaciated 


tubes  need  no  longer  worry  about  a 
means  of  bringing  back  their  life.  How- 
ever, neither  the  tube  manufacturers' 
method  of  restoring  life  by  allowing  the 
tubes  to  remain  lighted  without  the  B 
battery  on,  nor  the  transformer  method 


CONTRIBUTORS 
Name  Address  City 

R.  S.  Parks _ 1419  Cleveland  Blvd.- Caldwell,  Idaho 

Clement  Hampton.... 427  Jeanne  Mance  St Montreal,  Canada 

Walter  E.  Fee 115  Beecher  St Atlanta,  Ga. 

Carl  Wininger.... ..20  William  St St.  Catharines,  Can.i 

Joseph  A.  Smith 723  Wallace  Ave Wilkinsburg,  Pa. 

Francis  Davis - Cushing,  Okla. 

DIAL   TWISTERS 

Albert  C.  McKee 2306  Seminary  Ave ....Chicago,  111. 

P.  French..... .1209  Franklin  St Beaumont,  Texas] 

A.  Robert 327a  Richmond  St. Montreal,  Canada 

William  Laning 325  North  Bambry  St._ Philadelphia,  Pa. 

Alfred  T.  Chandler. 280  Randol  Ave San  Jose,  Calif. 

Charles  H.  Leach. 1000  Van  Buren  St. Chicago,  111. 

James  P.  Williamson.. 327  Dorion  St .Montreal,  Canada 

Warren  King 100  South  Crest  Road Chattanooga,  Tenn. 

Homer  W.  Good R.  F.  D.  l._. Wescosville,  Pa. 

H.  Bowden._ Box  44,  R.  F.  D.  1,  Mt.View.Plainville,  Conn. 

Mrs.  Eva  A.  Taylor 69  Murdock  St Youngstown,  Ohio 

Fergus  Mackay Grange  St ....Pictou,    N.   S.,   Can. 

Kermit  Fisher 4335  Jacob  St Wheeling,  W.  Va. 

Ackley  T.  Bush.... .941  No.  University  Ave Shawnee,  Okla. 

A.  C.  Taylor Steele,  N.  Dakota 

Floid  Omond 1.6  Alsace  Ave Buffalo,  N.  Y. 

D.  C.  Atkinson 788  Hohman  St ...Hammond,  Ind. 

C.  C.  Peugh. — 54  Linden  St..._ Schenectady,  N.  Y. 

Kendall  McNeil Ottawa,  Canada 

Jack  Cordy Box  251 Globe,  Arizona 

C.  A.  Hendrick ....Horizon  Apts Venice,  Calif. 

George  A.  Moutsatson.. 265  Ohio  St.. BentonHarbor.Mich. 

E.  N.  Girard 715  South  58th  St.... Philadelphia,  Pa. 

Roy  R.  Winder : Pedro  Miguel,  Canal   Zone 

Charles  Markarian ...110  Summer  St Worcester,  Mass. 

Lyle  F.  White ....523  So.  Washington  St Kankakee,  111. 

A.  L.  Snow 619  Hendrie  Blvd ...Royal  Oak,  Mich. 

E.  C.  Kelley._ Underhill,  Vt. 

Earl  Hamden,  Jr._ Globe,  Ariz. 

John  Hogle. 321  Selma  Ave Kenosha,  Wis. 

Henry  W.  Werner,  Jr._ .Box  419 Valhalla,  N.  Y. 

W.  Manning,  Jr. 619  Princess  St Woodstock,  Can. 

Robert  B.  Otto.. 85  Lowell  St Mathuen,  Mass. 

Frank  Barclay.. — R.  M.  D.  1, ..Victoria,  B.  C,  Can. 

Edward  Nolan__._ ....657  Tenth  Ave .New  York,  N.  Y. 

Allan  S.  Wilson 244  Kenwood  Ave Dayton,  Ohio 

Harold  W.  Fairley 121  Gilmour  Ave —.Toronto,   Canada 

Robert  W.  Barnhill 116  East  9th  Ave..._ Bristow,  Okla. 

Harold  A.  Reynolds 229  North  Montello  St_ Brockton,  Mass. 

Wallace  Buxton 4166  Emerald  Ave Oakland,  Calif. 

George  A.  Winkle .....902  South  15th  St Birmingham,  Ala 

J.  A.  Myers,  Jr .944  West  Capitol  St Jackson,  Miss. 

M.  E.  Walter 117  Lafayette  St Niles,  Ohio 

Fred  Brunton - - - ....Anaconda,  Mont. 

Cecil  Carrigg - 215  21st  Ave... San  Francisco,  Calif 

William  Heinochowitz 135  Johnson  Ave Newark,  N.  J. 

George  D.  Hillstrom__ .....10135  Lafayette  Ave._ Chicago,  111. 

D.  Gabelhouse - Vegreville,  Alta. ,  Canada 


44 


RADIO  AGE  for  July,  1925 


An  old  reliable  crystal  circuit,  one  of  the  early  types  used  in  the    U.  S.  and  still  popular 
with  those  who  do  not  care  for  the  expense  of  a  tube  set  for  short  distance  reception  on 

headphones 


mentioned  before,  will  restore  a  filament 
from  which  the  spark  of  life  has  departed 
due  to  a  breakage.  When  someone 
invents  a  filament  restorer  for  burned 
out  filaments  he  will  be  kissed  on  the 
brow  by  all  the  broadcast  listeners,  the 
amateurs  and  the  owners  of  broadcasting 
stations,  although  doubtless  the  tube 
manufacturers  would  chase  him  into  the 
wilds  of  Patagonia  with  a  sawed  off  shot- 
gun. 

At  the  last  moment  in  our  June  issue 
we  were  able  to  get  together  interesting 
data  on  the  binocular  and  toroid  coils 
which  are  designed  to  eliminate  the  neces- 
sity for  neutralization  in  radio  frequency 
amplifiers.  The  Pickups  Editor  will  be 
glad  to  hear  from  readers  of  RADIO 
AGE  as  to  the  success  encountered  with 
these  new  types  of  fieldless  inductances. 

Here's  a  fan  who  is  even  willing  that 
shoes  should  be  shied  at  him,  but  he  has 
the  courage  of  his  convictions  and  writes 
us  as  follows: 

"An  interested  observer  may  be  intim- 
idated many  times  before  making  his 
debut  into  a  certain  field ;  but  there  comes 
a  time  when  he  can  restrain  himself  no 
longer,  and  makes  a  headlong  dash 
by  giving  his  views  on  a  subject.  His 
suggestions  may  be  of  little  benefit  and 
then  again  they  might  open  up  a  way  for 
something  better.  It  is  with  the  latter 
in  view  I  write  this. 

"Possibly  you  have  meant  the  Pickups 


and  Hookups  Department  to  be  what  it  is 
— no  more,  but  personally  I  believe  that 
you  gave  this  section  of  your  magazine 
to  the  experimenter  for  a  means  of  radio 
development.  If  so,  then  it  is  up  to  the 
contributor  to  use  it  and  use  it  widely. 

Dx  Lists? 

"DX  lists  do  not  occupy  a  seat  of 
honor  in  my  household  simply  because 
I  do  not  invite  them,  or  to  put  it  in  the 
words  of  an  amateur,  T  didn't  get  the 
Pacific  Coast  because  I  was  not  fishing.' 
To  me  the  logging  of  numerous  stations 
merely  for  a  long  list  is  a  waste  of  time. 
The  logging  of  twenty-nine  stations  in  so 
many  minutes  as  given  by  one  of  the 
contributors  is  laughable.  May  I  ask 
how  many  of  us  today  would  know  any- 
thing of  radio  and  its  possibilities  if  the 
early  experimenters  spent  all  their  time 
at  such  foolish  toying?  Wouldn't  it  be 
of  more  interest  and  of  more  educational 
value  if  the  contributors  to  this  depart- 
ment gave  discussions  of  different  cir- 
cuits, as  many  are  doing,  effect  of  weath- 
er conditions,  code  interference  and  most 
of   all,    receiver   interference? 

"You  will  also  notice  that  this  section 
contains  hookups,  nine-tenths  of  which 
are   of  the  regenerative,  one-tube  type. 

"Fine,  I  say,  in  the  hands  of  one  who 
knows  how  to  use  them  without  spoiling 
half  a  dozen  neighbors'  good  natures. 
But  how  few  of  us  there  are  who  are  ideal. 


The  Magazine  of  the  Hour 

Down  with  regeneration?  No!  Em- 
phatically no!  Let's  keep  it,  but  not 
abuse   it. 

"This  is  merely  a  suggestion  and  many 
an  old  shoe  will  be  shied  at  me,  I'll 
venture,  yet  I  hope  it  may  stimulate 
others  to  give  their  views." 

The  writer  of  the  above,  R.  S.  Parks, 
1419  Cleveland  Boulevard,  Caldwell, 
Idaho,  seems  to  put  the  case  up  not 
so  much  to  this  department  but  to  fan- 
dom,  since  it  has  been  the  policy  of 
RADIO  AGE  to  give  its  readers  what 
they  desire.  If  there  has  been  a  desire 
for  DX  lists,  it  is  simply  because  the 
burden  of  the  Editor's  mail  has  been 
of  that  type.  If  the  single  tube  regenera- 
tive has  been  unduly  touted  in  these 
columns,  it  is  merely  because  so  far  the 
majority  of  the  contributors  seem  to 
have  been  most  impressed  with  it.  We 
realize  there  is  a  growing  demand  for 
the  experimenter's  section  in  this  de- 
partment, but  so  far  the  genus  experi- 
menter has  not  made  his  voice  heard. 

Perhaps  the  publication  of  the  above 
letter  and  the  comment  made  will  serve 
to  stir  up  interest.  Perhaps  it  will  lead 
to  the  creation  of  a  band  of  experimen- 
ters who  have  passed  the  one  tube  stage 
and  wish  eagerly  for  more  experiences, 
although  RADIO  AGE  cannot  very  well 
afford  to  forget  the  beginners  who  have 
many  more  problems  than  those  who 
have  already  taken  the  dive  into  the  pool 
of  radio  and   have  learned  to  swim. 

Henceforth,  we  will  watch  the  mail 
very  carefully,  and  the  tenor  of  the  de- 
partment will  be  merely  a  reflection  of  the 
contributions  received.  It  is  up  to  readers 
like  Mr.  Parks  to  sound  the  call  to  arms 
to  his  fellows;  then  let  the  station  list 
enthusiasts  marshal  their  forces.  May 
the  better  man  win;  we  feel  our  readers 
will  always  wish  us  to  abide  by  the  de- 
sires of  the   majority. 


Old  timers  will  readily  recognize  the 
circuit  in  Figure  1  as  the  inductively  or 
loose-coupled  crystal  set,  with  an  arrange- 
ment for  switching  from  the  use  of  car- 
borundum and  a  potentiometer  to  galena 
and  other  types  of  crystal  on  which  no 
battery  current  is  used.  In  the  old  days 
the  carborundum  was  considered  good 
because  it  was  fairly  stable  and  rugged 
and  would  stand  the  lurch  of  the  ship 
and  the  pound  of  the  engines  at  sea. 

It  is  sent  in  by  Clement  Hampton, 
427  Jeanne  Mance  St.,  Montreal,  Que., 
Canada,  who  says  his  old  friend,  W.  J. 
Featherstone  of  213  Ella  St.,  Hull,  East 
York,  England,  passed  it  on  to  him. 

The  antenna  variable  is  a  .001  and  the 
secondary  a  .0005  mfd.  The  inductances 
can  be  either  honeycombs,  a  loose  coup- 
ler, two  spiderwebs,  or  almost  any  form 
of  good  inductance.  A  fixed  condenser 
across  the  phones  would  do  no  particular 
harm  and  might  help  a  little. 

This  circuit  is  popular  in  England 
where  no  one  is  allowed  to  use  a  regenera- 
tive set  capable  of  feeding  energy  into  the 
antenna,  and  where  the  distances  are  not 
great, asis  the  case  in  the  British  Isles  and 
continental   Europe. 


Known    under    seventeen    or   eighteen 
different    names,    the    circuit    shown    in 


RADIO  AGE  for  July,  1925 

Figure  2,  and  sent  in  by  Walter  E.  Fee,  of 
115  Beecher  St.,  Atlanta,  Ga.,  is  the 
single  circuit  Armstrong,  noted  for  its 
ability  to  squeal,  and  one  of  the  oldest 
regenerative  sets  known  to  experimen- 
ters. L  2  is  inductively  placed  against 
L  1  for  feedback. 

In  Atlanta  this  circuit  works  out  quite 
nicely  (though  we  hardly  dare  think 
what  the  neighbors  have  to  say  on  this 
subject  when  the  tube  is  oscillating). 
It  tunes  in  the  long  distance  stuff  while 
WSB  is  batting  out  flies,  and  for  a  change 
Mr.  Fee  hooks  it  on  a  loop  and  goes  fish- 
ing for  distance,  with  results  as  follows: 
WSMB,  WOC,  WEAF,  WCCO,  KDKA, 
KSD,  WOAW  and  WQJ.  Of  course,  this 
is  used  on  head  phones  only.  It  is  one  of 
the  tried  and  true  types  of  receivers, 
although  not  recommended  for  congested 
areas  where  your  neighbor  mignt  have 
one   too. 


The  Magazine  of  the  Hour 


45 


Here's  another  one  familiar  to  the 
fellows  who  have  been  following  the  game 
for  longer  than  a  couple  of  years.  The 
circuit  sent  in  by  Carl  Wininger,  20 
WilliamSt.,  St. Catherine's, Ont., Canada, 
was  originally  published  by  Weagant 
shortly  after  Armstrong  gave  the  world 
his  regenerative  circuit.  Later  Weag- 
ant's  circuit  was  taken  up  and  popular- 
ized by  Reinartz.  It  has  masqueraded 
under  a  thousand  different  names,  but, 
the  circuit  fundamentally  is  the  same 
which  is  the  point  in  which  most  experi- 
menters are  interested. 

Instead  of  using  a  variable  regenerative 
coil  for  control  of  oscillation,  the  Weagant 
circuit,  alias  Reinartz,  alias  et  al,  uses  a 
variable  capacity  in  series  with  an  induc- 
tance, the  two  paralleling  the  plate  and 
filament.  The  control  of  oscillations 
seems  easier  with  this  type  of  receiver 
than  with  the  straight  variable  plate  coil. 

The  receiver  shown  in  Fig.  3  happens  to 
be  the  single  circuit  Weagant,  which  can 
be  made  up  with  honeycombs,  spider- 
webs,  straight  winding  on  a  tube,  or  any 
other  form  of  inductance.  While  it  is 
good  for  excellent  wcrk  on  distant 
stations,  for  the  sake  of  other  listeners  it 
would  be  best  to  loose  couple  it,  by  having 
an  untuned  primary  in  inductive  relation 
to  L  1.  The  condensers  in  the  circuit 
shown  are  .0005  mfd.  Reinartz  found 
that  oscillations  could  be  better  controlled 
by  inserting  a  small  choke  in  series  with 
the  phone  lead  at  the  point  marked  X 
in  the  diagram. 

In  the  inductively  coupled  receiver  the 
condenser  CI  spans  LI,  while  the  an- 
tenna comes  down  through  a  fifteen  turn 
coil  to  ground.  The  secondary  is  then 
removed  from  direct  contact  with  the 
aerial  and  if  the  receiver  does  feed  back 
into  the  aerial  it  will  be  with  lessened 
energy. 

LI  can  be  approximately  fifty  to  seven- 
ty-five turns,  while  L2  can  be  somewhere 
between  thirty-five  and  fifty  turns,  the 
condenser  C2  making  it  unnecessary 
for  the  exact  number  of  turns  to  be  found 
for  the  inductance  L2. 

Another  form  of  the  Armstrong  re- 
generative is  sent  in  by  Joseph  A.  Smith, 
723  Wallace  Ave.,  Wilkinsburg,  Pa.,  who 
tells  of  the  good  work  it  has  done  for 
him.     He  says  it  is  good  away  from  con- 


D" 


^5WS 


r^ 


A 
'III  I-1 


B 


fio  -Z" 


This  is  the  single  circuit  Armstrong.    L  2  is  inductively  coupled  to  L  1  for  feedback  pur- 
poses, and  its  relationship  is  variable.   The  inductance  change  in  L  1  is  by  means  of  laps 
and  the  condenser  in  the  antenna  circuit.    Good  for  results  but  hard  on  your  neighbor  if 
you  let  your  tube  oscillate 


Fi&Tir 


Another  popular  type  of  receiver  in  which  regenerative  control  is  by  a  variable  capacity 
in  series  with  an  inductance  paralleling  the  plate  and  filament.  Known  years  ago  at 
the  Weagant  circuit,  later  popularized  by  Reinartz  and  others.  Better  build  it  loos; 
coupled  for  the  sake  of  the  neighbors,  unless  you  happen  to  live  out  in  the  exact  geographical 
center  of  the  Gobi  desert 


46 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


gested  districts.  His  coils  are  wound  as 
follows:  L2  52  turns  18  or  20  DSC  on  a 
three  or  three  and  a  half  inch  form. 
Around  center  of  winding  one  layer  three 
quarters  inch  cambric.  Stick  8  pieces  of 
hard  rubber  3-4  by  3-16  by  1-4  placed 
equidistant  around  the  piece  of  cambric, 
fastened  with  collodion.  Coil  LI  is 
wound  on  these  blocks  and  consists  of  3 
to  10  turns  of  the  same  wire.  An  ordi- 
nary plate  variometer  is  used  for  L3. 
CI  is  .0005  and  C2  .001  mfd.  This  cir- 
cuit is  inductive  and  even  if  oscillating 
would  not  cause  the  same  amount  of 
annoyance  which  a  single  circuit  would. 
He  submits  a  list  of  DX  stuff  that  cer- 
tainly entitles  him  to  the  DT  button. 


Another  circuit  which  has  proved  very 
popular  with  those  who  wished  to  econo- 
mize on  tubes  and  material,  is  the  reflex 
circuit,  originally  attributed  to  Latour, 
the  Frenchman,  who  gave  it  to  the  Allied 
communication  authorities  during  the 
early  part  of  the  war  and  which  was 
immediately  pounced  upon  by  everyone 
on  this  side  of  the  water  as  an  excellent 
circuit  from  an  economical  standpoint. 
It  has  been  rearranged  countless  times 
and  additions  and  deletions  made  to  the 
original. 

This  circuit,  Fig.  V,  is  sent  in  by  Fran- 
cis Davis  of  Cushing,  Okla.,  who  tells  us 
LI  is  wound  on  a  3  inch  tube  with  15 
turns  of  No.  22;  L2  same  size  tube  with 
50  turns;  L3  is  the  same  as  LI  and  L4 
is  the  same  as  L3.  The  variables  CI 
and  C2  are  .0005  mfd.  C3  is  .00025  and 
C4  is  .001  mfd. 

Davis'  list  of  DX  stations  also  gets 
him  the  DT  button. 


Looks  like  the  ladies  are  not  to  be 
prevented  from  having  equal  rights  in 
radio  as  well  as  economics,  for  in  this 
week's     mail     come     two     letters     from 


An  inductively  coupled  Armstrong  regenerative.    Coils  LI  and  LZ  are  wound  by  the  con- 
tributor, while  Ui  is  an  ordinary  plate  variometer.     He  gets  good  results  on  it,  as  he  should 
with  a  loose  coupled  regenerative  set. 


feminine  fans,  the  first  from  Floid 
Omond,  16  Alsace  Ave.,  Buffalo,  N.  Y., 
who  finds  RADIO  AGE  interesting  in 
every  way,  and  specially  the  Pickups 
and  Hookups.  She  has  built  a  one 
tube  and  a  three  tube  set  and  has  re- 
ceived fine  DX  stuff  with  these.  So 
we  will  send  her  a  button,  but  regret 
we  haven't  a  little  wisp  of  ribbon  to 
send  along  with  it;  we  used  up  the  last 
piece  in   winding  a  coil. 

The  other  feminine  ether  chaser  is 
Mrs.  Eva  A.  Taylor,  69  Murdock  St., 
Youngstown,  Ohio,  who  reads  RADIO 
AGE  with  a  great  deal  of  interest,  espe- 
cially since  she  ran  across  one  of  the 
Youngstownian  names  in  the  magazine. 
She  has  qualified  for  the  button  by 
sending    in    a    list    of    stations    she    has 


received  on  a  manufactured  four  tube 
set  with  built  in  loud-speaker.  She 
wonders  if  there  is  anybody  in  Chicago 
who  does  not  own  a  broadcasting  sta- 
tion, as  her  experience  on  the  air  seems 
to  show  that  nearly  everybody  in  Chi- 
cago  is   broadcasting. 


We  got  quite  a  laugh  out  of  a  letter 
from  Albert  C.  McKee,  2306  Seminary 
Ave.,  Chicago,  111.,  who  says  his  set  is 
in  a  second  edition  of  "Hell's  Kitchen" 
where  he  has  to  contend  with  regenera- 
tive squeals  and  howls.  In  his  letter 
he  tells  of  making  a  crystal  detector 
out  of  an  old  mouse  trap  but  fails  to 
tell  whether  he  was  bothered  with 
squeaks  on  account  of  this  fact.  He 
(Turn  to  page  48) 


Another  popular  circuit,  the  reflex  which  sprang  from  Latour,  the  Frenchman,  during  the  war.   It  is  simple,  effective  and  economi- 
cal.    What  more  can  the  fan  ask!     This  one  was  sent  in  by  Francis  Davis,  of  Cushing,  Okla. 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


47 


% 


Jfie  Marine  (ftha  Hour 


Offers  to  Its  Readers  the 
First  Feature  of  Its  Kind  Ever  Published  in 

a  Radio  Magazine 

A  Round-up  of 
Hook-ups 

ALL  Basic  Circuits  from  which  ALL  Radio  Hook-ups 
are  Developed  Described  and  Illustrated  with 

62-Page  Blueprint  Section 


FOR   the   first   time   in   any 
radio    magazine,    RADIO 


AGE  is  publishing  in  its 
August,  1925,  issue,  an  array 
of  radio  hookups  that  will 
impress  and  delight  every 
lover  of  technical  radio  infor- 
mation and  accuracy. 

In  this  big  number,  which 
is  to  be  our  "Deluxe  August 
issue,"  RADIO  AGE  will 
prove    its    superiority    in    the 

technical  field  by  giving  its  readers,  at  no  additional 
cost  for  the  magazine,  many  pages  of  hookups,  from  the 
early  diagrams  to  the  very  latest  developments '  in 
multi-tube  design. 

Because  of  the  inevitable  popularity  of  this  number, 
and  the  demand  its  publication  will  cause,  readers  are 
asked  to  order  copies  in  advance. 


In  the 

"De  Luxe" 

August  Issue 

of  RADIO  AGE, 

Out  July  15 


THIS   unusual   number   will 
sell   for  the  usual   price  of 


25c  a  copy.  Of  the  pages 
in  this  number,  fully  56  will 
contain  actual  constructional 
articles,  of  which  THIRTY 
OR  MORE  pages  will  be  typi- 
cal RADIO  AGE  blueprints, 
which  have  made  the  "Maga- 
zine of  the  Hour"  distinctively 
famous  the  world  over. 

From  the  simplest  crystal 
set,  the  articles  in  this  number  will  enable  the  reader  to 
travel  by  an  orderly  process  to  the  super-heterodyne, 
taking  in  every  popular  type  of  receiver  introduced 
since  the  advent  of  the  radio  science. 

Where  improvements  have  been  made,  the  latest 
technical  explanations  will  be  given.  Everything  will 
be  strictly  up-to-the-minute,  and  written  so  clearly 
and  simply  that  either  the  rawest  novice  or  the  most 
seasoned  technical  expert  will  understand  the  articles 
almost  at  a  glance. 


Order  Your  Copy  of  This  Wonder  Issue  In  Advance ! 


25  CENTS  A  COPY, 
$2.50  A  YEAR 


RADIO  AGE,  Inc., 


500  N.DEARBORN  ST. 
CHICAGO 


48 


RADIO  AGE  for  July,  1925 


(From  page  46) 
thinks  J.  B.  Rathbun,  who  makes  up 
the  blueprints  for  the  various  hookups 
appearing  in  RADIO  AGE,  is  to  be 
■complimented  on  their  uniform  accuracy 
and  efficiency.  He  is  using  a  five  tube 
refiexed  radio  frequency  set  recently 
described  by  Rathbun  and  gets  won- 
derful results  with  it.  His  list  of  sta- 
tions entitles  him  to  the  button  all  right. 


did  help  his  set  to  such  an  extent  that 
he  logged  quite  a  batch  of  DX  stuff, 
for  which  he  is  hereby  awarded  the 
D.  T.  emblem. 


George  D.  Hillstrom,  10135  Lafayette 
Ave.,  Chicago,  111.,  is  a  14  year  old 
youngster  who  is  following  RADIO 
AGE  circuits  with  great  success.  His 
letter  containing  a  DX  list  entitles  him 
to   one   of    the   coveted    buttons. 


A.  C.  Taylor,  Steele,  North 
says  he  finds  there  is  no  other 
tion  that  deals  with  radio  that 
■a  vast  amount  of  good  readin 
as  RADIO  AGE  has.  He  say 
surprised  to  see  the  circuit 
E.  H.  Jones  in  the  April  num 
feels  that  too  much  cannot  be 
such  a  circuit. 


Dakota, 
publica- 
has  such 
I  matter 
;  he  was 
used  by 
ber,  and 
said  for 


George  A.  Winkler,  902  South  15th 
St..  Birmingham,  Alabama,  wants  RA- 
DIO AGE  to  keep  on  pouring  it  into 
a  certain  radio  octopus  with  which 
we  are  all  acquainted.  He  sends  in  a 
diagram  of  an  eight  tube  super  which 
he  is  using  with   good  results. 


P.  E.  Chapman,  805  North  Preston 
St.,  West  Philadelphia,  Pa.,  thinks 
RADIO  AGE  is  the  best  on  the  market 
and  reads  it  with  great  interest.  He 
thinks  our  invitation  to  readers  and 
experimenters  to  forward  their  results 
with  new  circuits  is  certainly  a  boost 
to  the  amateur  and  a  great  help  to  all 
who  are  interested  in  radio.  He  is  still 
using  the  four-tube  circuit  published 
by  RADIO  AGE  in  September,  1924, 
and  with  it  has  logged  167  stations; 
three  Europeans,  two  Cubans,  five 
Canadians,  six  Pacific  coast  and  one 
Alaskan 


Charles  Markarian,  110  Summer  St., 
Worcester,  Mass.,  gets  fine  results  with 
the  refiexed  neutrodyne  described  by 
Mr.  Hopkins  in  the  January  issue  of 
RADIO  AGE. 


P.  French,  1209  Franklin  St.,  Beau- 
mont, Texas,  took  us  at  our  word  as  to 
Spring  cleaning  referred  to  in  the  May 
RADIO  AGE.  He  reports  that  Spring 
cleaning   from   aerial   to   ground   clamps 


T.  L.  Kent,  721  North  Ave.,  Wau- 
kegan,  111.,  formerly  6US,  is  now  out 
of  the  "ham"  and  into  the  BCL  game, 
which    he    likes   very    much. 

John  Hogle,  of  321  Selma  Ave., 
Kenosha,  Wis.,  says  he  is  bothered  by 
only  one  station,  that  being  Zion.  He 
asks  for  a  wave  trap  that  will  obliterate 
that  station.  He  has  made  up  his 
set  from  RADIO  AGE  blueprints.  He 
gets  excellent  results  from  his  three 
circuit  regenerative.  A  wave  trap  might 
be  used  on  Zion  with  good  results.  Make 
it  on  a  cardboard  form  about  three 
inches     in     diameter,     winding    it    with 


The  Magazine  of  the  Hour 

about  fifty  turns  of  No.  18  bell  wire 
(also  known  as  annunciator  wire),  span- 
ning it  with  one  of  the  Remler  con- 
densers he  uses.  Insert  in  series  with 
the  aerial  lead  of  your  normal  primary 
and  tune  to  Zion's  wave,  leaving  it 
there  while  you  chase  off  in  quest  of 
other   signals. 


Roy  R.  Winder,  Pedro  Miguel,  Canal 
Zone,  sends  word  of  his  luck  with  radio 
in  the  land  of  static  down  around  "Pete- 
Mike"  on  the  Panama  Canal.  The 
first  station  he  has  a  chance  to  pick 
up  is  PWX,  Havana,  about  900  miles 
to  the  northward.  He  is  a  regular  reader 
of  RADIO  AGE,  considering  it  one  of 
the   most   valuable   assets  of  radio. 


Another  fourteen-year-old  radio  fan 
is  E.  N.  Girard,  715  South  58th  St., 
Philadelphia,  Pa.,  who  uses  RADIO 
AGE  hookups  as  his  guide.  He  gets 
out  of  town  stuff  without  trouble  from 
the  locals  and  sends  in  a  dandy  DX  list. 


Kendall  McNeil,  of  Ottawa,  who 
neglects  to  send  his  address,  writes 
interestingly  of  his  excellent  results 
with  the  improved  three  tube  Reinartz 
described  in  the  May  RADIO  AGE 
by  Mr.  Piety.  He  gets  all  the  stations 
in  the  U.  S.  and  also  nabbed  two  or 
three  of  the  Continentals,  namely  Lon- 
don, Newcastle  and  Aberdeen,  all  of 
which  he  has  confirmed. 


D.  C.  Atkinson,  788  Hohman  St., 
Hammond,  Ind.,  one  day  used  his 
downspout  on  the  eave-troughs  of  the 
house  instead  of  an  antenna,  getting 
stronger  signals.  He  used  this  on  a 
crystal  set,  but  says  he  has  not  tried 
it  on  a  tube  set  yet.  Let's  hope  his 
experience  will  not  start  an  epidemic 
of  down-spouting  or  else  all  the  land- 
lords in  the  country  will  be  faced  with 
the  necessity  of  installing  tinned  copper 
downspouts  with  binding  post  con- 
nections for  each  experimenter.  Many 
tin  roofs  have  worked  better  than  a 
poor  antenna,  but  always  remember 
there    is    NO    substitute    for    a    GOOD 


How  are 

Your  DX  Lists 

Coming  This 

Summer? 

Let  the 

"Pickups  and 

Hookups" 

Readers 

Know  About 

Them! 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


49 


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"The  Roundup  of  Hookups!" — 1 1 2  pages  of  every  conceivable  kind  of  radio  hookups — will  be  the  big  feature  of  the 
"Deluxe"  Edition  of  the  August  RADIO  AGE.  On  the  stands  July  15,  but  order  your  copy  in  advance  if  you 
want  to  get  this  wonder  issue.     More  than  thirty  pages  of  blueprints  and  scores  of  hookups!     25  cents  a  copy. 

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50 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


The  Broadcast  of  Plays 
Written  for  Radio 

By  E.  E.  Mattson 
Westinghouse  K  Y  W 

SINCE  the  advent  of  radio,  its  progress 
has  brought  many  improvements, 
some  of  them  expected  and  some  not 
looked  for.  However,  improvements  from 
a  technical  point  of  view  have  not  been 
the  only  goal  sought  in  radio.  From  the 
beginning  radio  was  popular  because  of 
its  newness,  its  mysteries  and  seeming 
intangibility.  A  person  bit  by  the  radio 
bug  soon  became  almost  diabolical  in  his 
lust  to  grope  into  the  distance,  and  spared 
no  effort  to  purchase  or  build  a  set  that 
brought  him  clear  and  distinct  reception. 
Those  were  fascinations  that  led  him  on. 
With  the  advance  of  radio  activity,  and 
the  many  angles  taught  its  leaders  by 
experience  and  study,  it  became  apparent 
that  the  mere  broadcasting  of  vocal  or 
instrumental  numbers  accompanied  by 
conventional  announcing  would  not  suf- 
fice. The  rendition  was  heard  well  but  it 
appeared  automatic,  it  lacked  the  per- 
sonality that  would  make  it  pleasing  and 
beautiful.  The  artist  was  taught  to  im- 
press the  invisible  listener-in  by  sound, 
what  the  stage  artist  did  by  pantomime. 
The  announcer  was  given  the  idea  of 
making  his  remarks  fit  the  occasion  and 
blending  them  into  the  program  as 
part  of  it,  thereby  assisting  the  proper 
balancing  of  the  act.  These,  and  many 
other  things  were  essential. 

After  about  four  years  of  radio  activity, 
numerous  ideas  have  presented  them- 
selves to  radio  directors,  visualizing  the 
need  of  a  change  of  venue.  Wilson 
Wetherbee,  director  of  Westinghouse 
Station  K  Y  W,  has  long  felt  this  need 
and  for  some  time  past  has  been  active  in 
coaching  the  personnel  of  K  Y  W  toward 
this  goal.  Radio  broadcasting  demands 
new  things,  and  it  will  get  it.  The  movie 
industry  started  with  one-reel  features, 
and  during  its  evolution  it  grew  until 
today  the  cinema  features  full  plays 
brought  out  with  a  studied  skill,  wherein 
the  personality  of  the  actressesand  actors, 
aided  by  elaborate  stage  settings,  convey 
to  the  audience  the  same  impressions  that 
the  spoken  drama  would.  The  success  of 
the  movie  is  evident  by  its  popularity 
among  all  classes,  the  highly  educated 
and  those  less  favored. 

A  Radio  Technique 

Mr.  Wetherbee's  ideas  have  brought 
out  that  radio  thirsts  for  something  more 
than  "one  reelers."  His  experience  has 
taught  him  a  technique  of  radio  more 
than  the  mere  announcing  of  a  selection 
and  then  putting  it  over  clear  and  dis- 
tinct. The  announcer,  the  artists,  the 
stage  setting — all  are  unseen  by  the 
listener.  The  general  atmosphere  has  to 
be  impressed  upon  the  listener  by  sound, 
and  by  the  personality  injected  into  the 
microphone  in  the  studio.  So  far  this 
policy  has  succeeded  admirably.  Now 
Mr.  Wetherbee's  plans  bring  forth  radio's 
demand  of  short  acts,  in  which  several 
persons  take  part,  and  in  which  the 
scenes  are  laid  with  the  same  care  and 
aforethought  as  on  the  stage  or  in  a 
photo-studio.  With  radio,  however, 
technique  finds  employment  in  drawing 


for  the  listener-in  a  vision  of  the  layout 
concerning  which  he  hears  the  spoken 
version.  In  the  movie,  the  audience  sees 
but  does  not  hear.  In  the  radio,  it  hears 
and  will  see  by  virtue  of  the  impression 
that  will  be  given  the  listener  by  the 
personnel  of  the  act. 

It  is  the  purpose  of  Station  K  Y  W  to 
give  life  to  this  plan.  Mr.  Wetherbee  will 
supervise  the  writing  of  plays  to  be  used 
over  K  Y  W.  He  has  completed  the  first 
one  act  play,  "The  Fates  Decide"  which 
will  soon  be  put  on  the  ether.  In  this 
play  he  employs  three  people,  Norman 
Landon,  a  wealthy  newspaper  owner, 
Marion  Landon,  his  wife,  and  Franklin 
Ames,  his  life  long  friend.  The  entire 
plot  is  laid  out  with  the  same  care  and 
thought  as  given  a  play  for  the  stage.  It 
will  be  acted  by  three  artists  of  the  sta- 
tion, who  have  been  coached  in  rehearsal 
until  the  effect  intended  has  been  brought 
out  to  a  high   degree. 


Summer  Radio  Conditions 
To  Be  Surveyed 

H  FRANK  Hopkins  and  Harvey  T. 
Kelley,  Assoc,  I.  R.  E.,  and  well 
*  known  radio  engineers,  plan  to 
leave  Chicago  some  time  during  August 
on  an  extended  trip  throughout  the  West- 
ern and  Southwestern  portion  of  the 
United  States,  to  carry  on  an  intensive 
survey  of  broadcasting  conditions  in  so- 
called  "dead  spots." 

Because  radio  reception  is  so  difficult 
in  the  Summer-time,  under  most  condi- 
tions, the  two  experts  will  endeavor  to 
trace  the  causes  and  record  them  for 
public  use.  Their  findings  will  be  sent 
for  publication  in  RADlO  AGE  as  the 
trip    progresses. 

A  100- watt  broadcasting  station  will 
be  part  of  the  equipment  carried  on  this 
trip,  and  arrangements  have  been  made 
to  carry  on  tests  in  Colorado,  Utah, 
Arizona,  New  Mexico,  Southern  Cali- 
fornia, and  where  static  conditions  at 
this  time  of  the  year  are  unusual.  Under 
these  extremely  adverse  conditions,  an 
attempt  will  be  made  to  determine  just 
what  kind  of  radio  circuit  performs  the 
best.  Several  circuits  will  be  taken  on' 
the  trip  and  tested  under  varying 
atmospheric  and  geographic  conditions. 

Communication  with  Eastern  and 
Pacific  broadcasting  stations  will  be 
maintained  throughout  the  long  trek, 
which  will  be  made  by  automobile. 
Several  stations  have  expressed  a  desire 
to  broadcast  the  findings  of  the  experts, 
to  guide  them  in  reaching  districts  and 
listeners  in  isolated  parts  of  the  world 
who  at  present  encounter  difficulties 
in  maintaining  consistent  touch  with 
radio  stations  throughout  the  year,  and 
especially    in     the    Summer-time. 

Mr.  Hopkins  and  Mr.  Kelley  intend  to 
devise  several  new  types  of  radio  appa- 
ratus to  meet  the  difficulties  they  expect 
will  confront  them.  These  varied  types 
of  apparatus,  which  will  be  designed 
after  thorough  tests,  will  be  described  to 
readers  of  RADiO  AGE  this  Fall, 
thereby  being  of  great  value  to  those 
fans  who  live  far  from  strong  stations 
and  who  are  bothered  by  static,  fading 
and  other  unaccountable  disturbances. 
Both  Mr.  Hopkins  and  Mr.  Kelley 
have  long  been  identified  in  radio 
circles,  having  done  much  research  and 
development  work.  Both  are  past 
masters  in  the  transmitting  and  receiving 
art. 


How  Much  Coupling  is 
Necessary? 

(  Continued  from  page  14) 

In  making  the  final  primary  coil,  it  is 
best  to  allow  taps  at  two  or  three  turns 
more  than  necessary  on  long  waves  and 
at  least  two  less  than  necessary  to  pro- 
duce oscillations  on  short  waves.  This 
makes  sufficient  allowance  for  depreciat- 
ing tubes  and  batteries. 

The  variable  coupler  makes  up  for 
lots  of  little  differences  in  sets,  such  as 
aerials  of  different  capacities,  tubes  of 
more  or  less  oscillatory  tendencies, 
batteries  differing  in  voltage,  detectors 
of  more  or  less  absorbing  powers  and  the 
like.  It  avoids  the  necessity  for  variable 
feed-back  coils  like  reversed  ticklers,  for 
inducing  regeneration  on  some  wave- 
lengths and  counter-acting  it  on  others. 
And  it  permits  long  wave  stations  to 
come  in  as  well  as  others;  in  fact,  it  makes 
reception  uniform  all  over  the  dial's 
scale. 


Phonograph  Stores  Are 
Handling  Radio 

NEW  YORK— Radio  parts  are  now 
being  handled  by  phonograph  stores 
throughout  the  country  and  on  a  grow- 
ing scale,  declared  Ben  Aplin,  eastern 
sales  manager  for  the  Shaw  Insulator 
Co.,  of  Irvington-Newark,  N.  J.  Mr. 
Aplin,  who  is  one  of  the  best  known 
salesmanagers  for  molded  radio  materials 
in  this  country,  has  been  deeply  im- 
pressed by  the  increasing  volume  of 
sales  being  recorded  by  phonograph  and 
music  stores  for  small  parts  which  hold 
such  an  important  part  in  the  radio 
industry. 

"Hundreds  of  dealers  throughout  the 
eastern  section  of  the  country  who 
previously  handled  musical  instruments 
and  records,  and  eventually  added  radio 
sets  have  been  finding  that  small  parts 
have  been  invaluable  sources  of  profit 
to  their  sales  total. 

"This  fact  is  more  apparent  as  one, 
in  travelling  throughout  the  greater 
cities,  finds  that  dealers  everywhere  are 
adding  small  parts  as  the  direct  results 
of  demands  made  upon  them  by  their 
trade.  There  are  always  some  parts  of 
their  set  which  they  desire  to  replace 
to  add  greatly  to  the  efficiency  of  their 
sets. 

"With  that  idea  in  mind  they  go  to 
the  music  store  which  sold  them  the  set 
and  insist  upon  buying  some  particular 
part.  If  the  dealer  does  not  carry  that 
part  or  for  that  matter  any  part  in  stock 
the  customer  goes  elsewhere.  The 
natural  result  is  that  the  dealer,  rather 
than  see  business  going  to  another  store, 
gradually  stocks  up  new  and  small 
parts  which  he  finds  hold  ready  sales 
appeal   to   his  customer. 

"Many  dealers  were  first  of  the  oelief 
that  the  carrying  of  small  parts  would 
be  the  means  of  cluttering  up  their 
stock.  Instead  they  are  gradually  finding 
that  by  simplifying  the  arrangement 
of  their  merchandise  they  are  able  to 
fill    the    customers,     demands    at  once. 

"It  is  no  longer  necessary  to  spread 
these  small  parts  in  every  section  of  the 
store.  They  are  now  systematizing 
their  stocks  of  these  small  radio  parts 
with  the  result  that  a  show  case  or  two 
in  a  particular  section  of  the  store  carries 
the  stock  required. 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


51 


The  Radio  Spies 

(Continued  from  page  32) 
occasions  seen  this  same  Cecelia  Lambert  at  the 
De  Forest  plant  in  Jersey  City.  I  was  likewise  told 
by  another  employe  who  was  working  under  Harley, 
whose  name  I  do  not  recall,  that  there  was  at  that 
time  another  investigator  stationed  at  the  De 
Forest  plant  who  was  known  as  'E-10-'  " 

After  saying  that  he  arranged  for  Thies  to  procure 
certain  information  concerning  the  complainant. 
Bowlby  declares  he  passed  on  Thies's  written  report 
to  Harley.  adding,  "this  report  contained,  among 
other  things,  a  description  of  all  the  machinery  used 
in  the  tube  department  of  the  De  Forest  Radio 
Company  while  he. was  working  there,  as  far  as  he 
could  remember  the  same,  together  with  the  method 
of  operating  these  machines;  also  the  information 
regarding  filament  wire  used  by  that  company  in 
making  its  tubes  and  where  they  obtained  the 
same." 

Bernice  M.  Jennings,  employed  as  typist  by  the 
Radio  Corporation  of  America  from  November,  1924. 
to  April,  1925,  said  an  employment  agency  sent  her 
to  Room  301,  25  Beaver  Street,  where  she  asked  for 
Mr.  Harley.  She  was  engaged  by  a  Mr.  Silverton. 
There  were  six  girls  under  Mr.  Harley  in  Rooms  301 
and  302.  she  says.  Harley 's  private  office  was 
Room  303.  She  alleges  that  Room  217  in  the  same 
building  was  also  occupied  by  a  girl  under  Harley's 
direction  and  was  also  used  by  Radio  Corporation's 
investigators. 

Instructed  on  Secrecy 

Soon  after  she  began  work,  alleges  Miss  Jennings, 
she  was  told  by  several  other  employes  in  the  office 
not  to  give  out  any  information  regarding  the  people 
in  the  three  rooms,  or  their  business-,  and  also  not 
to  let  anybody  know  that  there  was  any  connection 
between  the  employes  there  and  the  Radio  Corpora- 
tion of  America.  Two  weeks  later  she  was  trans- 
ferred to  Room  217.  Once  a  man  dropped  in  and 
asked  for  Mr.  Harley.  She  directed  him  to  Room 
301.  When  Harley  heard  of  the  incident  he  is  alleged 
to  have  said  to  Miss  Jennings,  "In  the  future,  if 
any  one  comes  here  and  asks  for  me.  you  don't  know 
me  nor  anything  about  me.  and  no  one  here  has 
anything  to  do  with  any  radio  business  whatever." 

Harley.  the  affidavit  continues,  received  written 
reports  from  many  investigators.  They  were  usually 
stamped  with  Harley's  initials  and  then  went  to 
Silverton.  who  stamped  them  with  his  designation, 
"C-2." 

When  she  first  began  copying  the  reports,  says 
Miss  Jennings  in  her  affidavit,  they  were  headed  by 
the  name  of  the  person  or  concern  under  investi- 
gation. For  three  months  prior  to  April  10.  1925, 
she  received  almost  daily  reports  from  "C-3," 
Cecilia  Lambert,  reports  headed  "In  re  De  Forest," 
but  subsequently  the  heading  was  changed  to  "381" 
and  that  number  was  given  to  the  file  which  contain- 
ed matters  relating  to  the  De  Forest  Company. 

The  reports  covered  many  things,  the  affidavit 
alleges,  including  the  time  employes  began  and  quit 
work,  "whether  there  were  few  or  many  employes  at 
work,  whether  they  worked  overtime  or  less  than 
full  time,  whether  business  was  brisk  or  slow,  what 
employes  were  discharged  and  what  new  ones  were 
taken  on,  the  names  and  addresses  of  employes,  so 
far  as  she  was  able  to  give  them:  instructions  issued 
to  foremen  and  persons  in  charge,  notices  posted  in 
the  departments  governing  the  personnel  of  superin- 
tendents and  foremen,  why  a  foreman  had  been  laid 
off,  efforts  made  to  speed  up  production,  and  espe- 
cially what  took  place  in  the  power  tube  depart- 
ment: on  two  or  three  occasions  her  reports  contained 
attempted  drawings  of  machines  used  in  the  depart- 
ment in  which  she  was  working." 

Several  times  Miss  Lambert,  it  was  alleged,  sent 
in  with  her  report  some  pieces  of  filament  wire,  and 
she  also  sent  in  what  she  designated  as  "gold  seals." 
used  in  connection  with  the  manufacture  of  power 
tubes. 

Corroborates  Bowlby 

William  Buckbee,  a  tester  in  the  De  Forest  Labo- 
ratory, swears  in  an  affidavit  that  in  company  with  a 
young  lady  he  met  Harley,  at  the  latter's  sugges- 
tion. With  Harley  was  Miss  Johnson,  whom  Buck- 
bee  says  he  knew  to  be  a  De  Forest  employe.  Harley. 
Buckbee  asserts,  told  him  that  Miss  Johnson  was 
an  investigator  for  the  Radio  Corporation  and  that 
she  was  one  of  five  or  six  employed  in  the  De  Forest 
plant  who  were  also  employed  by  the  defendant. 

"At  that  interview."  the  affidavit  continues. 
"Harley  offered  the  young  lady  accompanying  me  a 
position  as  confidential  investigator  for  the  Radio 
Corporation  of  America  and  stated  to  her  that  as 
such  confidential  investigator  he  could  get  her  a 
position  with  the  De  Forest  Radio  Company,  as 
stenographer,  and  that  he  wanted  her,  after  having 
(Turn  to  page  60) 


Through  the  Locals— > 
ALL- AMAX  Reaches  Out 

Every  All'Amax  Set,  wherever  it  may  be,  brings  to 
its  owner  his  choice  of  all  the  beauties  in  the  air. 
Every  day  come  more  and  more  letters  to  our  office, 
telling  of  the  long  distance  reception,  almost  unbeliev 
able  on  a  three 'tube  set,  which  has  rewarded  the 
owners  of  All'Amax. 


# 


Remember,  too,  that  All'Amax  is  completely  mounted 
on  panel  and  baseboard.  You  can  wire  it  in  one  delightful 
evening,  following  simple  photographic  instructions. 


ALL-AMAX  SENIOR,  three  tubes  and  detector 
ALL-AMAX  JUNIOR,  one  tube  and  detector  .    . 


Price,  $42.00 
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ALL-AMERICAN   RADIO  CORPORATION 

E.  N.  RAULAND,  President 


2680  Coyne  Street 


Chicago 


All-American 


Institute  Correction 


We  are  reprint- 
ing views  of  the  t  wo 
condensers  with 
their  proper  identi- 
fications. The  top 
view  here  wit  h 
shows  the  Quam  ^ 
condenser,  and  the  *~ 
cut  at  the  bottom 
is  a  Duplex 
Matched    Conden- 


Through  an 
error,  the  illus- 
trations of  Tests 
No.  47  and  49 
in  the  RADIO 
AGE  Institute 
for  May,  1925, 
were  reversed. 
The  Quam  Con- 
denser test  was 
illustrated  by 
an  engraving  of 
the  Duplex 
..  Condenser,  and 
vice   versa. 


*     Tested  and  Approved  by  RADIO   AGE 


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52 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Standard   Radio   Receivers 

Recently  RADIO  ACE  inaugurated  a  new  department  called  "Know  Before 
You  Buy,"  to  serve  as  a  guide  to  the  prospective  radio  purchaser  in  deciding  on  the 
receiver  best  suited  to  his  individual  needs.  Fans  throughout  the  country  have  shown 
an  instantaneous  response  to  this  new  feature,  and  accordingly  it  is  continued  and 
will  be  a  feature  of  all  forthcoming  numbers  of  RADIO  ACE.  Readers  are  invited 
to  write  us  concerning  the  sets  in  which  they  are  interested,  and  manufacturers  also 
are  asked  to  send  us  material  describing  their  sets 


Selectivity  Paramount 
in  Chelsea  Sets 

THE  Chelsea  Three  and  Five  Tube 
receivers  have  been  designed  with 
virtually  one  end  in  view:  that  of  attain- 
ing-the  ultimate  in  selectivity. 

The  Chelsea  Super  Five,  just  announc- 
ed, is  a  five  tube  receiver  embodying  this 
selectivity  with  unusual  volume.  Dis- 
tortion is  minimized  so  it  isunnoticeable, 
as  is  any  annoying  squealing. 

The  Chelsea  Five  has  all  the  principles 
of  the  perfected  non-regenerative  set, 
including  remarkable  distance.  The 
cabinet,  of  the  sloping  type,  is  finished 
in  rich  mahogany  with  shielded  Bakelite. 
The  retail  price  is  now  §50. 

The  Three  Tube  Chelsea 

Clear  volume  on  the  loud  speaker,  with 
ability  to  bring  in  distant  stations  within 
reasonable  rangs,  is  the  feature  of  the 
Three-Tube  Chelsea,  Model  122.  This 
set  has  been  on  the  market  for  some  time 
and  has  gained  a  reputation  for  its  con- 
sistently remarkable  performance.  _  One 
station  is  received  at  a  time,  proving  it 
is  also  selective. 

The  Chelsea  3-Tube  Set  is  of  the  triple 
circuit  type,  controlled  by  a  single  tuner. 
No  knowledge  of  radio  is  necessary  to 
operate  this  simple  receiver.  The  cabinet 
is  slightly  sloping,  as  in  the  Chelsea 
Super   Five.      It   is   of   attractive   finish. 

The  price  is  now  $40.00. 

The  Eaglet  Receiver  a  "Prince 
of  the  Air" 

THE  EAGLET,  a  three  tube  dry  cell 
neutrodyne,  has  been  "weighed  in 
the  balance"  of  engineer's  tests,  and  has 
proved     that     it     possesses     selectivity, 


volume  as  well  as  simplicity,  distance 
and  tone  volume.  These  qualities, 
coupled  with  good  workmanship,  finish 
and  guarantee,  constitute  the  last  word 
in    radio. 

The  Eaglet  embodies  the   Eagle   Bal- 
anced    Neutrodyne     circuit,     using    one 


step  of  tuned  radio  frequency  ampli- 
fication, vacuum  tube  detector  and  two 
steps  of  audio  amplification.  The  first 
tube  is  reflexed;  that  is,  it  amplifies  radio 
and  audio  frequency  at  the  same  time; 
making  the  Eaglet  virtually  a  four  tube 
receiver. 

It  gives  reception  equivalent  to  a  four 
tube  dry  cell  set,  using  only  the  current 
required  by  three  tubes.  The  Eaglet  is 
portable  in  the  sense  that  it  is  light  of 
weight,  can  be  conveniently  carried 
about  the  house  and  can  be  hooked  up 
to  different  antennas,  taken  out  in  an 
auto,  used  on  camping  trips,  Summer 
homes  and  hospitals. 

For  its  operation  it  requires  three 
No.  6  dry  cell  A  batteries  1  }4  volt,  and 
four  No.  23}/2  B  intermediate  size  or 
one  4}/2  volt  unit  C.  The  tubes  are 
UV  199  vacuum  tubes  or  their  equiva- 
lent. The  instrument  can  be  operated 
with  ear  phones  or  loud  speaker.  The 
installation  is  the  same  as  the  Eagle 
model  B;  namely,  approximately  100 
feet  antenna.  Two  antenna  leads  are 
provided,  one  for  long  and  one  for  short' 
aerial. 

The  receiver  is  a  delicate,  scientific 
instrument,  and  should  not  be  tampered 
with  by  inexperienced  people.  •  The 
Eaglet  has  been  welcomed  both  by  the 
trade  and  the  consumers  and  has  already 
endeared  itself  to  thousands  of  owners. 
Families  spending  the  hot  months  in 
camps,  mountains,  or  sea  shore  will  find 
the  Eaglet  a  source  of  great  joy  and  will 
be  able  to  keep  in  touch  with  the  wonder- 
ful open  air  orchestra  programs  that  are 
always  broadcast  during  vacation  time 
from  the  country's  best  stations.  The 
water  enthusiast  can  listen  in  and  have 
a  whale  of  a  time  with  his  Eaglet  installed 
on  yacht  or  motor  boat,  on  account  of 
its  compact  design  and  light  weight. 

The  price  is  §75.00. 


"Tone  Modulator"  in 
Resas  Receiver 

T^HE  perfected  Resas  Tone-A-Dyne 
-*-  receiver  embodies  every  advantageous 
feature  claimed  for  any  five  tube  set, 
plus  the  Tone  Modulator,  a  feature 
that  is  to  be  had  only  with  the  TONE- 
A-DYNE. 

As  its  name  implies,  the  Tone  Modu- 
lator controls  the  tone  and  volume  at 
all  times  and  under  all  operating  con- 
ditions. There  is  nothing  complicated 
or  difficult  about  it.     Simply  a  turn  of 


the  knob  and  the  musical  or  vocal  selec- 
tion assumes  its  most   pleasant  volume. 

The  Tone-A-Dyne  is  non-radiating. 
Annoyance  from  squeals  and  howls  is 
eliminated. 

The  selectivity  of  the  Tone-A-Dyne 
is  unusually  satisfactory.  With  local 
stations  broadcasting  on  a  wavelength 
only  5  meters  away,  station  WHAS 
(Louisville)  has  been  readily  tuned  in 
without  interference  on  a  short  indoor 
aerial. 

The  Tone-A-Dyne  is  so  designed  that 
it  can  be  operated  by  anyone  without 
previous  experience.  The  three  tuning 
dials  are  accurately  calibrated  and 
matched  so  that  their  settings  practically 
correspond.  There  is  only  one  filament 
control,  and  this  can  be  set  at  the  best 
operating  point  on  reception  of  the  first 
station.  A  snap  switch  controls  all 
tubes.  Clearly  marked  binding  posts  are 
provided  in  the  rear  for  all  connections. 

The  price  is  §78.00.  (Turn  to  page  54) 


RADIO  AGE  for  July,  1925 

Learning  the  Various  Tube 
Characteristics 

( Continued  from  page  12) 
operation.  This  condition  usually  comes 
suddenly;  it  is  not  spread  out  over  the 
life  of  the  tube  as  would  be  expected. 
It  is  sometimes  caused  by  applying 
excessive  voltage  to  the  filament  of  an 
otherwise  good  tube.  If  such  is  the  case, 
it  is  possible  to  restore  the  tube  to  normal 
by  the  rejuvenation  process,  or  by  apply- 
ing the  rated  voltage  to  the  filament 
with  the  plate  voltage  cut  off,  for  about 
a  half  hour. 

From  the  above  it  will  be  seen  how 
an  old  or  defective  tube  will  cause  the 
aging  of  the  ofher  tubes  in  a  circuit. 
This  condition  is  readily  noted  by  the 
necessity  of  increased  "A"  battery 
voltage — but  most  fans  just  turn  the 
rheostats  on  and  let  it  go  at  that — 
paralyzing  or  otherwise  decreasing  the 
efficiency  of  all  of  the  tubes,  which  is  a 
rather  expensive  performance  in  the  end. 

Amplification  Factor 

TX)  DETERMINE  the  amplification 
■■■  factor  of  a  vacuum  tube  experiment- 
ally, a  high  frequency  current  of  about 
1,000  cycles  is  necessary — along  with  a 
hot  wire  galvanometer  and  other  asso- 
ciated equipment.  However,  it  is  pos- 
sible to  determine  this  factor  by  use  of 
the  plate  current  values  of  the  tube  under 
test,  substituting  approximate  values  for 
functions  of  the  various  voltages  in  the 
tube.  Thus, — I— a  (-yEb +  EC +e)  2  in 
which  I  equals  the  Thermionic  current 
in  milliamperes,  Eb  equals  the  potential 
(voltage)  difference  between  the  plate  and 
filament,  E0  equals  the  potential  (voltage) 
of  the  grid  and  «  is  an  arbitrary  quantity 
representing  the  small  differences  of 
potential  (voltage)  existing  in  the  tube 
under  various  conditions,  o  is  a  struc- 
tural constant. 

The  quantity  y  in  this  equasion  is  as 
explained  in  volume  47 — 1918 — "Physical 
Review"  by  Van  der  Bijl — "That  for 
equivalent  values  of  Eb  and  Ec,  a  change 
in  the  cinode  (plate)  voltage  Eb  produces 
7  times  as  great  a  change  in  the  current 
to  the  cinode  as  an  equal  change  in  the 
grid  voltage  E0" — or  non-technically — a 
change  in  voltage  on  the  plate  would 
have  to  be  y  times  the  voltage  change 
on  the  grid  that  would  be  required  to 
produce  a  given  change  in  the  plate  cur- 
rent. The  voltage  amplification  factor 
H  is  the  reciprocal  of  this  quantity   or 

This  is  shown  graphically  in  figure  2 — 
where  the  grid  and  plate  curves  are  drawn 
to  the  same  scale  on  the  same  chart,  indi- 
cating that  a  much  smaller  change  in 
grid  voltage  will  produce  a  greater  change 
in  plate  current  than  a  like  change  in 
plate  voltage  will  produce. 

The  ratio  of  the  two  voltages  required 
to  produce  a  given  change  in  plate  current 
is  the  amplification  factor  (ju2)  on  the 
chart;  the  ratio  of  the  slopes  of  the  straight 
portions  of  these  curves  is  the  amplifica- 
tion factor. 

The  amplification   factor  of  the   tube 

plotted  on  this  chart  will  be  between  6 

and  6.25  or  an  average  of  6.125.     With 

this  average   factor  we  have  7  =  1/6125 

(Turn  to  page  56) 


The  Magazine  of  the  Hour 


53 


The  "Better  Tuning"  Control 

A  New  B  -  T  Product 


Hairline  Control,  Easy  Action, 
Simple  Mounting. 

No  side  strain  or  pull  on  shaft  to 
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Reads  0  to  100  or  100  to  0, — set- 
tling the  argument  as  to  "clock- 
wise" or  "anti-clockwise"  instru- 
ments. 

Registers  dial  numbers,  wave 
lengths,  or  call  letters. 

_    ,     .      .  ,   „  ,    .      Improves  the  tuning  as  well  as 

Exclusive  features  fully  protected  Q 

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The  new  Tuning  Control  is  distinctively  a  B-T  product.  It  is  of 
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You  should  know  about  the  new  B-T  socket.  Send  your  name 
and  address  for  circulars  on  this  and  other  new  B-T  developments. 


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532  S.  Canal  St.,   Chicago 


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54 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


LIFE, 
LIBERTY 

and  the  Pursuit  of 

HAPPINESS! 


You  Won't  Have 
to 

Pursue 
HAPPINESS 

You  can  ha  ve  it  right  at  your  elbow 
to  while  away  the  time  'til  old  Lady 
Static  gets  off  the  line! 

You'll  have  no  trouble  getting 
station  Z-I-F-F-S,  because  you'll 
find  it  is  always  tuned  in  to  catch 
your  funny  bone's  wavelength,  and 
is  more  ticklish  to  your  giggle  box 
than  the  finest  cat  whisker! 

ZIFFS,  Badzib's  Book  of  Art 
and  Wit,  is  the  only  humorous 
monthly  of  its  kind  on  the  market, 
and  is  crammed  full  of  the  best 
artists  and  funsters  in  the  world! 

Exclusive  Photo  Section!  Com- 
plete gallery  of  French-American 
Art  Studies  in  color!  Fifty  pages  of 
illustrations!  Pep,  Ginger,  Punch! 
ALL  FOR  TWO  BITS! 

Pick  This  Out  On 
Your  Piccolo ! 

Even  tho'  your  set  is  growling 

'Til  you  think  a  cat  is  howling 
A.nd  the  music  comes  in  wailing,  hissing  sniffs. 

You  will  giggle,  grin  and  chuckle 

'Til  you  ha/ta  loose  the  buckle 
On  your  belt,  if  you've  the  latest  book  of  ZIFFS 

You  wouldn't  go  fishing  without 
bait,  would  you?  Well,  then,  don't 
try  to  get  Hong  Kong  on  a  stormy 
night  with  a  crystal  set,  till  you've 
put  your  John  Henry  on  the  tag 
below: 


ZIFFS, 

608  South  Dearborn, 
f   Chicago,  111. 
DearBadzib: 

II  got  a  radio.  I  got  Hawaii.  I  got  drowned 
out.     I  got  peeved. 

(I  don't  see  nothin*  to  laugh  at,  you  big  bum! 
Here's  two  bits.  Send  me  the  July  ZIFFS,  and 
I  will! 


H 


They  Call  Me . 
And  I  live  at. . 


Standard  Radio  Receivers; 
The  Atwater  Kent 


( Continued  from  page  52) 


Atwater  Kent  Carefully 
Designed 

THE  careful  construction  of  Atwater 
Kent  Radio  is  apparent  to  the  most 
casual  observer — the  easy  movement  of 
the  tuning  dials;  the  absence  of  intricate 
wiring;  the  sturdiness  and  rigidity  of 
the  various  parts,  are  but  a  few  of  its 
features.  Other  structural  details  worthy 
of  particular  note  are: 

Variable  condensers:  plates — coun- 
terbalanced; bearings — adjustable  cone, 
machine  ground;  contact  spring — phos- 
phor bronze. 

Dials:  drilled  and  reamed  after 
moulding,  assuring  balance  and  accurate 
fit  on  the  condenser  shaft. 

Rheostats:  phosphor  bronze  spring 
contact,  sliding  on  spiral  resistance  coil, 
giving  smooth   and   positive  action. 

Tube  sockets:  heavy  brass  set  in 
moulded  Bakelite  base  with  phosphor 
bronze  contact  springs,  corrugated  to 
make  good  contact. 

Transformers:  special  Atwater  Kent 
design  capable  of  receiving  all  broad- 
casting. 

Grid  leak:  special  cartridge  type, 
absolutely  quiet  in  operation. 

Wiring:  tinned  copper  with  all  joints 
firmly  soldered,  spaghetti  covered  where 
there  is  a  difference  in  potential. 

Shielding:  a  metal  panel  on  the 
cabinet  receivers  and  metal  shields  on 
condensers  of  the  open  models  entirely 
eliminate  all  body  capacity. 

Loud  speaker:  fabricated  entirely  of 
metal,  the  same  as  the  vast  majority  of 
the  finest  band  instruments. 

Diaphragms:  of  special  alloy  metal, 
unusually  large  in  diameter,  assuring 
great  volume  without  distortion. 

Magnets:  special  Atwater  Kent,  re- 
quiring no  extra  batteries. 

Many  types  of  radio  receiving  sets 
deliver  a  sufficient  volume  of  sound  from 
distant  broadcasting  stations,  but  they 
are  not  selective — that  is,  they  cannot 
separate  two  stations,  both  broadcasting 
at  the  same  time  on  waves  of  nearly 
the  same  wavelength. 


Atwater  Kent  Receiving  Sets  overcome 
these  difficulties  to  a  marked  degree, 
so  that  two  or  more  stations  broadcasting 
at  the  same  time  can  be  separated  and 
the  desired  station  tuned  in  clearly  and 
without  troublesome  interference. 

One  of  the  most  pleasing  features  of 
Atwater  Kent  receiving  sets  is  their 
sureness  of  securing  a  desired  broad- 
casting station. 

A  printed  list  is  supplied  with  each 
set  which  gives  the  approximate  dial 
setting  of  many  of  the  well-known 
broadcasting  stations.  With  this  key 
list  in  hand,  the  owner  of  an  Atwater 
Kent  can  tune  in  a  series  of  desired  sta- 
tions, or  stations  operating  on  similar 
wavelengths.  By  writing  down  the 
dial  readings  opposite  the  names  of  the 
stations,  make  up  a  list  or  "log." 

Model'20  is  a  powerful  receiver  capable 
of  operating  a  loud  speaker  under  all 
conditions  where  broadcasting  is  at  all 
practicable — hence  ear  phones  are  unne- 
cessary. It  comprises  two  stages  of 
tuned  radio  frequency  amplification,  a 
detector  and  two  stages  of  audio  fre- 
quency amplification  with  three  tuning 
dials.  It  is  non-radiating  and  non- 
squealing. 

Dimensions:  Height,  8  1-2  in.;  length, 
26  in.;  depth,  8  3-4  in.  Number  of  tubes 
required,  5. 

Part  No.  4640,  Model  20  Cabinet 
Receiving  Set,  $100.00. 

Open  receiver,  same  as  Model  20  but 
without  cabinet — $85.00. 


New  Studios  Ready  for 

wcco 

Work  has  started  on  the  new  Saint 
Paul  studios  of  the  Gold  Medal  Sta- 
tion, Saint  Paul-Minneapolis,  WCCO. 
These  studios  will  be  among  the  most  uni- 
quely located  in  the  world.  They  are  being 
built  in  Saint  Paul's  new  Union  Depot, 
used  by  nine  railroads.  The  studios, 
reception  room,  and  executive  offices, 
will  be  at  the  left  of  the  concourse 
through  which  all  persons  pass  going  to 
and  from  the  trains. 


THE  LATEST 

parts  and  sets  are  always  featured  in 
our  Salespeaker.  If  you  are  a  live- 
wire  dealer,  write  for  your  copy,  now. 

HUDSON-ROSS— 1 16  S.  Wells  St. 

Chicago 

Tested  and  Approved  by  RADIO  AGE 


A  regular  $25  loud  speaker  for 
$16.  Loud,  clear,  mellow  tone. 
Bell  13^i  in.  diameter,  horn 
22  in.  high,  equipped  with 
Lakeside  Adjustable  Unit. 
Agents  wanted,  write  for  par- 
ticulars. 

Lakeside  Supply  Co. 

73  W.  Van  Buren  St.,  Chicago 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


55 


A  Simplified  Portable 
Super-Het 

(Continued  fro^n  page  23) 

Lead  No.  14  of  the  battery  cable  is 
attached   to   Al   on   the   battery   switch. 

Attach  the  lug  at  the  end  of  the  2  3-4 
inch  section  of  Lead  Nor  17  to  the  poten- 
tiometer at  A2.  The  tap  is  attached  to 
the  battery  switch  at  A3  and  the  last 
lug   is   attached   to   the   rheostat   at  A4. 

Lead  No.  27  is  now  run  between 
the  rheostat  at  A5  and  the  negative  fila- 
ment line  at  A6. 

Lead  No.  18  runs  from  the  potentio- 
meter at  B2  to  the  positive  filament  line 
at  B3. 

The  lug  at  the  end  of  the  8  3-4  inch 
section  of  lead  No.  12  is  attached  to  the 
center  of  the  potentiometer  at  G.  The 
other  taps  of  this  lead  are  attached  to  the 
terminals  marked  "F"  on  the  third, 
second,  and  first  intermediate  frequency 
transformers.  These  are  points  Gl,  G2, 
and  G3  respectively. 

Attach  the  lug  at  the  4  1-4  inch  section 
of  lead  No.  2  to  the  rotor  plates  of  the 
loop  tuning  condenser  at  HI.  The  tap 
on  this  same  lead  connects  to  the  stator 
plates  of  the  balancing  condenser  at 
H2.  The  other  end  of  this  lead  later  con- 
nects to  one  side  of  the  loop. 

Attach  the  lug  at  the  end  of  the  7  1-4 
inch  section  of  lead  No.  15  to  the  rotor 
plates  of  the  balancing  condenser 
at  11.  The  tap  in  this  lead  connects  to 
the  plate  of  the  first  detector  tube  at  12 
and  the  remaining  lug  attaches  to  the 
"Plus"  terminal  of  the  first  intermediate 
frequency  transformer  at   13. 

The  lug  at  the  end  of  the  7  1-2  inch 
section  of  lead  No.  6  attaches  to  the  lower 
Jack  at  Dl.  The  next  tap  connects  to 
the  B  Positive  terminal  on  the  second 
audio  frequency  transformer  at  D2.  The 
remaining  lugs  attach  to  the  "Plus" 
terminals  on  the  fourth  (or  filter  trans- 
former), the  third  and  second  interme- 
diate transformers  respectively.  These 
connections  are  made  at  points  D3,  D4, 
and  D5. 

The  oscillator  coupler  should  now  be 
bolted  to  the  sub  base.  Use  6-32x5-16 
inch  machine  screws  for  this  purpose. 

Before  attaching  the  socket  strip  be 
sure  that  all  of  the  wires  which  you 
have  attached  so  far  are  as  close  to  the 
base  board  as  possible.  This  is  one  of 
the  few  "don'ts"  in  these  instructions 
and  should  be  observed. 

The  socket  strip  is  attached  by  means 
of  6-32x1  3-4  inch  machine  screws. 
Run  the  bolt  through  the  base  board, 
place  a  brass  washer  under  a  6-32  3-8 
inch  nut  and  secure  it  firmly.  Then 
run  another  3-8  inch  nut  down  the  bolt 
about  three  quarters  of  the  way.  The 
socket  strip  is  now  placed  in  position  and 
the  loose  nuts  on  the  underside  of  the 
strip  run  up  to  the  correct  point.  Fasten 
the  strip  firmly  in  place  by  nuts  screwed 
on  from  the  top  and  you  are  ready  to 
resume    wiring. 

Lead  No.  25  is  now  completed  from  G4 
on  the  .006  to  Gl,  the  Filament  terminal 
of  the  third  intermediate  frequency 
transformer. 

Lead  No.  22  is  completed  by  connect- 
ing from  D6  on  the  other  .006  condenser 
to  the  "Plus"  terminal  on  the  fourth  or 
filter  transformer,   D3. 

Connect  lead  No.  26  from  C4  on  the 
.005  condenser  to  the  B  plus  terminal 
on  the  first  audio  frequency  transformer, 
C2. 

Now  complete  lead  No.  32  from  A7, 
the  inside  terminal  of  the  pickup  coil  to 
the  negative  filament  line  of  the  socket 
strip  at  A8. 

(Turn  to  page  56) 


Radio  Fans 


— can  thank  Jewell  for  de- 
veloping a  small  receiving 
set  instrument  with  self 
contained  switch  for  multi- 
ple readings. 

CSAVES  — Space  and 
cost  of  additional  instru- 
ments. 


Pat. 
Pending 

Multiple   reading  instrument 
with  self  contained  switch 


£ 


<L  PERM  ITS— Testing  of 
"A"  and  "B"  batteries 
from  panel  of  your  set. 

CEvery  Radio  "Fan" 
should  have  our  15-B  cat- 
alog. 

Order  from  Dealer 


Jewell  Electrical  Instrument  Co. 


1650  Walnut  St. 


Chicago 


"25  Years  Making  Good  Instruments" 


The  Radio  Age  Annual  for  1924! 

ONLY  A  FEW  LEFT  AT  50c  EACH 

If  you  have  not  bought  your  copy  of  the  famous 
RADIO  AGE  ANNUAL  for  1924,  you  may  get  one 
at  a  special  price  of  50  cents  by  filling  in  the  coupon 
below  and  sending  it  with  stamps,  money  order  or 
draft,  at  once.  The  supply  is  nearly  exhausted,  and 
no  more  will  be  printed,  so  ACT  NOW! 

1924  ANNUAL  COUPON 
Radio  Age,  Inc., 

500  N.  Dearborn  St., 

Chicago,  111. 
Gentlemen:      Please  find  enclosed  50  cents,  for  which  you  may  send  me  a 
copy  of  the  RADIO  AGE  ANNUAL  for  1924,  in  accordance  with  your  special 
price  offer  for  April. 

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Tone  1  oud  and  pleasing. 
Handsome  material  and  design. 

Black,  $22.50     Shell,  $25.00 
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State  and  64th  Sta..  Chicago 


DA  HI  E  RADIO  CONSOLE 

ilfAULl   MFG.C0.562VEDDERST. 

CHICAGO.    WRITE    FOR    CIRCULAR 


56  RADIO  AGE  for  July,  1925 

Some  Sidelights  on  Tube 
Characteristics 

(Continued  from  page  53) 
or  .16.  Substituting  the  values  of  the 
co-ordinates  of  two  points  on  the  straight 
portion  of  the  plate  characteristic  in  this 
equation,  and  solving  simultaneously — 
with  Ec  as  zero — we  get  for  the  other 
constants — e=3.28  Volts  and  a  =  .0134 
the  equation  of  the  curve  is  then 
I  =.0134  (.16.  Eb4-Ec  +  3.28)2 

For  greater  amplification,  higher  plate 
voltage  will  be  necessary  and  a  negative 
grid  bias  with  a  "C"  battery  in  series 
will  be  used — the  correct  "C"  battery 
for  the  desired  amplification  may  be 
readily  determined  by  use  of  the  tube 
test  set  from  experiment.  The  average 
grid  voltages  for  the  199  type  of  tubes 
are: — 

Plate  Voltage  Grid  Bias  Voltage 

45  Volts _ 0.5  to  1.0  volts  negative 

67J4  volts. 1.5  to  3.0  volts  negative 

90  volts. .3.0  to  4.5  volts  negative 

112>2  volts 4.5  to  6.0  volts  negative 

The  output  impedance  of  a  tube  may 
be  taken  as  an  average  for  solving  this 
equation.  The  following  values  are  as 
correct  as  necessary  for  this  purpose  and 
may  be  used  with  a  close  degree  of 
accuracy. 

Mutual  Conductance 

The  mutual  conductance  is  the  usual 
average  for  each  type  shown.  A  tube 
should  show  close  to  that  noted  to  operate 
efficiently. 

Average  mu- 
tual conduct- 
Output        ance  (micro- 
Type  of  impedance  mohs)  of 
tube                       of  tube  tube 

199  19.600  ohms  315 

200  (detector)  10,000  ohms  Varies 

201  22,000  ohms  273 
201 A  15,400  ohms  345 
WD-11  or  WD-12  17,500  ohms  290 
VT  or  215A  18,500  ohms  350 
216A  (power  tube)  4,400  ohms  1360 


The  Magazine  of  the  Hour 


Simplicity  of  Construction  is 
Vital  in  Portable 


The  mutual  conductance  shown  in  the 
above  table  is  the  usual  average  for  tubes 
of  their  type — a  tube  should  show  close 
to  that  to  be  in  good  condition. 

To  make  it  more  easily  understood,  the 
type  of  tube  in  the  table  is  the  usual  code 
number  used  by  most  manufacturers. 
However,  to  more  clearly  explain  them, 
the  following  table  shows  the  rated  fila- 
ment voltage — plate  voltage,  Plate  R 
"B"  battery  current  drain,  and  average 
amplification  factor  for  each — 


Type  of 

Filament 

Plate 

Amp- 

lifica- 

Volts 

peres 

Volts 

peres 

factor 

199 

3.0 

0.06 

40 

.0009 

6.125 

200 

5.0 

1.00 

22.5 

.0003 

Varies 

201 

5.0 

1.00 

45 

.0009 

6.000 

201A 

5.0 

0.25 

45 

.0007 

6.500 

WD11-WD12 

1.1 

0.25 

45 

.0012 

5.200 

VT  or  215A 

1.1 

0.25 

45 

.0008 

6.500 

216A 

6.0         1.10 

125 

.0110 

6.000 

The  Chart  shown  in  Figure  four  is  an 
example  of  matching  tubes  graphically 
and  is  a  good  explanation  of  the  plate 
current  of  two  tubes  under  identical  con- 
ditions. The  curve  No.  1  shows  an 
efficient  tube,  to  work  well  at  normal 
filament  current,  while  curve  No.  2 
shows  a  tube  that  is  old  or  defective, 
producing  about  half  as  much  as  the  other 
tube. 


(Continued  from  page  55) 


Lead  No.  19  is  completed  from  J,  the 
inside  terminal  of  the  plate  section  to  the 
plate  of  the  oscillator  tube,  Jl. 

Complete  lead  No.  5  by  running  from 
the  outside  terminal  of  the  plate  section 
CI  to  the  B  positive  terminal  on  the  first 
audio  transformer,  C2,  and  to  the  "Plus" 
terminal  of  the  first  intermediate  trans- 
former, C3. 

Lead  No.  11  is  completed  from  the  in- 
side terminal  of  the  grid  section,  El,  to 
the  filament  terminal  on  the  first  audio 
transformer,  E3,  and  to  the  filament 
terminal  on  the  second  audio  transformer 
E2. 

From  the  outside  terminal  of  the  grid 
section,  K  run  lead  No.  13  to  the  grid  of 
the  oscillator  tube,  Kl,  and  to  the  stator 
plates  of  the  oscillator  condenser  at  K2. 

Lead  No.  10  is  attached  from  the 
battery  cable  to  the  filament  terminal 
of  the  first  audio  transformer  at  E3. 
This  is  the  C  battery  negative  connec- 
tion. 

Lead  No.  21  is  the  positive  filament 
wire  in  the  battery  cable  and  attaches  to 
the  positive  filament  line  on  the  socket 
strip.  The  second  socket  from  the  left 
can  be  used  for  this  purpose. 

The  B  battery  positive  detector  line  of 
the  battery  cable,  lead  No.  39,  may  now 
be  attached  to  the  "Plus"  terminal  on  the 
first  intermediate  frequency  transformer 
at  C3. 

Lead  No.  20  is  the  B  battery  positive 
amplifier  of  the  battery  cable  and  at- 
taches to  the  "Plus"  terminal  of  the  sec- 
ond intermediate  frequency  transformer 
at  D5. 

The  tap  on  lead  No.  1  is  now  attached 
from  the  first  grid  condenser  at  H5  to  the 
stator  plates  of  the  loop  tuning  condenser 
at  H6. 

Lead  No.  24  runs  from  the  rotor 
plates  of  the  oscillator  condenser,  E4, 
to  the  filament  terminal  of  the  first  audio 
frequency  transformer,  E3. 

Lead  No.  16  is  connected  by  the  lug 
at  the  end  of  the  4  inch  section  to  the 
upper  Jack,  V.  The  tap  connects  to 
the  plate  of  the  first  audio  tube,  VI,  and 
the  remaining  tap  is  connected  to  the 
plate  terminal  of  the  second  audio 
frequency  transformer,  V2. 

Lead  No.  36  runs  from  the  grid  of  the 
first  intermediate  frequency  tube,  M,  to 
the  grid  terminal  on  the  first  intermediate 
frequency  transformer,  Ml. 

Lead  No.  37  runs  from  the  grid  of  the 
second  intermediate  frequency  tube,  O, 
to  the  grid  terminal  on  the  second  inter- 
mediate  frequency   transformer,    01. 

Lead  No.  38,  connects  the  grid  of  the 
third  intermediate  frequency  tube,  Q, 
to  the  grid  terminal  of  the  third  inter- 
mediate frequency  transformer,   Ql. 

Lead  No.  29  connects  the  plate  of  the 
first  intermediate  frequency  tube,  N,  with 
the  plate  terminal  on  the  second  inter- 
mediate  frequency   transformer,    Nl. 

Lead  No.  30  runs  from  the  plate  of  the 
second  intermediate  frequency  tube,  P, 
to  the  plate  terminal  on  the  third  inter- 
mediate  frequency   transformer,    PI. 

Lead  No.  31  runs  from  the  plate  of  the 
third  intermediate  frequency  tube,  R, 
to  the  plate  connection  on  the  fourth 
or  filter  transformer,  Rl. 

Lead  No.  33  connects  the  positive 
filament    line    at    B3    with    the    filament 


terminal   on    the   fourth   or    filter   trans- 
former at  B5. 

Lead  No.  28  attaches  to  the  plate 
terminal  of  the  first  audio  transformer  at 
LI  and  runs  to  the  plate  of  the  second 
detector  tube,  L. 

Lead  No.  34  connects  the  grid  of  the 
first  audio  frequency  tube,  U,  with  the 
grid  terminal  on  the  first  audio  frequency 
transformer,  Ul. 

Lead  No.  42  runs  from  the  grid  of  the 
second  audio  frequency  tube,  W,  to  the 
grid  terminal  of  the  second  audio  fre- 
quency transformer,   Wl. 

The  grid  condenser  for  the  second 
detector  tube  is  now  mounted  on  the 
transformer  as  shown  in  the  diagram 
and  photograph.  The  easiest  way  to  do 
this  is  to  remove  the  regular  nut  from  the 
grid  terminal  of  the  filter  transformer 
and  screw  down  tightly  a  small  6-32  nut. 
The  regular  nut  is  now  replaced  and  as  a 
sufficient  amount  of  thread  is  now  ex- 
posed the  condenser  can  be  fastened  se- 
curely by  a  6-32  machine  screw  which 
has  been  cut  or  filed  to  the  correct  length. 
Lead  No.  41  is  then  attached  to  the  grid 
condenser  at  SI  and  to  the  grid  of  the 
second  detector  tube  at  S. 

Lead  No.  4  is  then  attached  to  the  plate 
of  the  second  detector  tube  and  the  wiring 
is  completed  in  the  set  itself. 

Lead   No.   7  shown  on  the  diagram  is 
later   used   to   connect   one   of   the   loud 
speaker  terminals  with  the    B    battery 
positive  amplifier  and  can  be  laid  aside 
until  it  is  needed. 

Three  22  1-2  volt  B  Batteries,  six 
ordinary  dry  cells,  and  a  C  Battery  are 
the   battery   supply. 

When  the  set  is  completed,  pass  the 
battery  cable  through  a  hole  drilled  in 
front  of  the  battery  partition  and  cut  the 
covering  of  the  cable  until  leads  of  suit- 
able length  are  exposed.  The  battery 
layout  shown  in  the  sketch  leaves  every- 
thing snug  but  there  are  several  combina- 
tions you  might  try.  Lead  No.  7  now 
comes  in  for  a  useful  career  as  the  connec- 
tion from  one  loud  speaker  terminal  to  the 
B  Battery  positive  amplifier. 

Leads  No.  1  and  No.  2  are  now  con- 
nected to  the  outside  terminals  of  the 
loop  windings  and  Lead  No.  3  connects 
with  the  center  tap  terminal  of  the  loop. 

When  all  the  tubes  are  in  the  set,  the 
batteries  hooked  up  and  the  loud  speaker 
connected,  pull  the  filament  switch  and 
adjust  the  rheostat  to  a  point  about  three 
quarters  of  the  way  on.  This  is  probably 
a  little  too  high  but  a  few  minutes  of 
excess  current  won't  hurt  the  tubes  par- 
ticularly and  we  are  at  least  certain  of 
having  enough.  Set  the  balancing  con- 
denser at  its  minimum  capacity  and  ad- 
vance the  potentiometer  until  a  slight 
hiss  is  heard  in  the  speaker.  If  this 
control  is  advanced  too  far  some  very 
violent  whistles  which  soon  merge  into  a 
loud  roar  are  likely  to  be  heard.  The 
loop  dial  and  the  oscillator  dial  both 
tube  very  closely  together  if  the  loop 
specifications  have  been  followed  and  it  is 
only  necessary  to  run  the  two  dials  to- 
gether from  about  five  on  the  dials  up  to 
eighty.  If  no  station  is  heard,  advance 
the  position  of  the  balancing  condenser 
slightly  and  again  cover  the  broadcast 
range.  When  a  station  is  tuned  in,  it 
may  be  brought  maximum  volume  bv 
continuing    to     advance     the     balancing 


RADIO  AGE  for  July,  1925 

condenser  and  the  potentiometer  until 
the  circuit  "spills  over."  Selectivity  in 
this  circuit  is  governed  chiefly  by  the 
amount  of  regeneration  present  in  the 
first  detector  tube  and  by  the  position  of 
the  potentiometer.  The  more  regenera- 
tion in  these  circuits,  the  sharper  the  set 
becomes.  Excess  regeneration  in  the 
first  detector  circuit  will  be  recognized 
by  the  "mushy"  quality  of  the  received 
signal  and  by  the  fact  that  the  oscillator 
dial  becomes  very  broad  in  tuning,  as 
the  detector  is  then  combining  the  func- 
tions of  both   a   detector   and  oscillator. 

The  grid  leaks  recommended  are  3 
megohms  in  the  first  detector  circuit 
and  5  megohms  in  the  second  detector 
circuit.  If  the  circuit  tunes  too  sharply 
or  if  volume  is  less  than  expected  on 
local  signals,  substitute  a  lower  value 
leak  in  the  first  detector  circuit. 

Body  capacity  should  not  be  present 
on  any  of  the  controls  except  the  small 
balancing  condenser.  Even  here  it  will 
not  be  particularly  noticeable  except  on 
distant  signals.  If  body  capacity  exists 
on  any  of  the  other  controls,  look  over  all 
connections,  particularly  those  of  the 
bypass  condensers. 


The  Magazine  of  the  Hour 


57 


5KW  Power  for  Cincinnati 
Stations 

WLW  and  WSAI,  two  broadcasters 
located  near  Cincinnati,  have  been 
authorized  to  use  power  as  high  as  5000 
watts.  This  information  may  come  as 
a  shock  to  some  skeptical  fans  who  have 
feared  any  great  increase  in  power,  for 
they  are  the  first  two  SKW  stations. 
The  new  licenses  catalogue  the  power  as 
"500  to  5000  watts."  It  is  requested 
that  they  use  discretion,  observing  sug- 
gestions of  the  district  radio  supervisor 
if  interference  is  created  by  the  increased 
power. 

The  main  factor,  which  influenced  the 
Department  of  Commerce  to  grant  these 
licenses,  was  the  fact  that  they  are  both 
located  out  of  town  where  any  reasonable 
interference  would  not  be  detrimental 
to  the  local  reception  of  distant  stations. 
WLW,  the  Crosley  station  is  in  Harrison, 
and  WSAI,  The  U.  S.  Playing  Card 
Station  is  in  Mason,  Ohio.  Radio 
officials  in  Washington  are  disposed  to 
grant  qualified  Class  B  stations  similar 
authority  for  increased  power,  if  their 
transmitters  are  set  up  outside  the  crowd- 
ed urban  districts. 

WEAF,  the  A.  T.  &  T.  Co.,  station  in 
New  York  has  been  authorized  to  increase 
its  power  to  2500  watts,  being  now  the 
next  highest  powered  station. 


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58  RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


Tracing  the  Interesting  Ancestry 
of  Your  Receiver 


IT  DOES  not  seem  so  long  ago  that 
we  were  listening  to  the  now  almost 
forgotten  spark  signals  with  the 
simple  little  crystal  set,  which  at  that 
time  was  considered  one  of  the  wonders 
of  the  age. 

Interest  in  this,  however,  was  confined 
to  a  few  amateurs  who  studied  the  code 
and  enjoyed  an  evening's  chat  with  their 
friends.  Then  came  the  radio  telephone, 
by  means  of  which  voice  and  music  could 
be  heard  with  these  rudely  constructed 
and  inefficient  sets.  Two  broadcasting 
stations  began  to  send  out  musical  pro- 
grams and  the  amateur  began  to  be 
popular.  People  began  to  call  at  his  little 
station  and  marvel  at  this  new  scientific 
toy,  to  ask  his  advice  as  to  how  they,  too, 
might  build  a  set  and  enjoy  this  pleasure, 
not  because  of  any  particular  desire  to 
learn  the  principles  of  radio  communica- 
tion, but  because  they  wanted  to  hearthis 
music  coming  from  the  air  and  to  enter- 
tain their  friends  with  this  newly  found 
amusement. 

More  broadcasting  stations  began  to 
operate  and  the  fever  spread  until  at 
the  present  time  radio  has  grown  to  be 
one  of  the  greatest  industries  in  the 
world.  In  the  beginning,  it  was  difficult 
to  construct  even  the  simple  crystal  set, 
the  parts  having  to  be  constructed  by 
the  operator  himself.  We  hadn't  a  radio 
store  on  every  corner  as  we  now  have. 
It  was  real  work. 

Improvement  Arrives 

WITH  the  opening  up  of  more  broad- 
castingstations  and  the  increase  in  the 
number  of  fans,  came  the  demand  for 
something  better  in  the  way  of  a  re- 
ceiving set.  Vacuum  tubes  began  to 
replace  the  crystal,  because  by  their  use 
the  signals  were  not  only  detected  as  they 
were  with  the  crystal,  but  they  were 
amplified  also,  this  being  made  possible 
by  the  addition  of  the  third  element  in  the 
tube,  called  the  grid,  which  was  produced 
by  the  inventive  genius  of  Dr.  Lee  De 
Forest.  These  vacuum  tubes,  however, 
were  expensive  in  the  old  days  and  only 
those  who  could  afford  luxuries  were 
lucky  enough  to  possess  them. 

Today  they  may  be  had  for  the  price  of 
one  dollar  and  up,  and  the  simple  little 
crystal  has  lost  its  prestige.  With  the 
advent  of  the  vacuum  tube  more  of  these 
amateurs  became  interested  in  the  actual 
science  and  as  a  result  of  their  untiring 
efforts,  we  now  have  radio  as  it  is  today. 
They  created  the  demand  for  better 
apparatus  and  improved  upon  the  few 
basic  circuits  until  we  now  have  hundreds 
of  circuits  in  use,  with  more  coming  all 
the  time. 

But  what  of  these  circuits?  As  a 
matter  of  fact,  there  are  only  a  few  of 
these   basic    circuits,    most    of   the   new 


By  FRANK  D.  PEARNE 

arrangements  being  only  improvements 
which  are  bound  to  come  from  this  vast 
army  of  experimenters.  Before  the 
World  War,  Major  Armstrong  announced 
his  regenerative  circuit,  which  was  a 
basic  idea,  but  since  that  time  the  only 
distinctive  new  circuit  which  has 
appeared  is  the  reflex,  the  production  of 
which  is  generally  attributed  to  Prof. 
Marius  Latour  of  France,  and  Arm- 
strong's Superheterodyne. 

Today  there  are  hundreds  of  sets 
advertised,  all  of  which  are  merely  modi- 
fications and  additions  to  these  five  or 
six  basic  circuits.  Among  these  are  the 
single-circuit  regenerative,  three  circuit 
regenerative,  superregenerative,  and  other 
forms  of  regenerative  or  radio  frequency 
amplefuation.  From  this  list  many  com- 
binations have  been  made,  radio  frequency 
amplification  has  been  added  and  hun- 
dreds of  little  kinks  here  and  there  have 
been  incorporated,  but  a  close  analysis 
will  reveal  the  fact  that  no  radical 
changes  in  the  old  basic  principles  have 
been  made.  There  are  many  people  at 
the  present  time  who  want  to  purchase 
sets  and  who  are  holding  off  and  waiting 
in  the  fear  that  something  new  is  shortly 
going  to  develop  which  will  make  their 
selection  obsolete. 

A  Foolish  Idea 

THIS  is  a  foolish  idea  which  is  not 
borne  out  by  the  past.  It  is  true,  per- 
haps, and  very  probable  that  many  new 
sets  will  appear  on  the  market  in  the 
next  year,  but  it  is  not  at  all  probable 
that  any  radical  change  will  take  place. 
There  is,  of  course,  a  possibility  that  the 
wave  band  of  the  broadcasting  stations 
may  be  slightly  increased,  due  to  the 
fact  that  so  many  applications  for 
licenses  are  being  received  by  the  Govern- 
ment that  they  find  the  present  wave 
band  too  narrow  to  accommodate  all  of 
them  and  keep  the  proper  separation. 
But  one  may  rest  assured  that  nothing 
will  be  done  to  make  the  present  type  of 
receiving  set  obsolete. 

Experiments  have  shown  that  it  is 
possible  to  broadcast  on  wavelengths  as 
low  as  100  meters,  but  it  will  probably 
be  a  long  time  before  the  wave  band  will 
be  broadened  to  this  point.  The  fact 
that  so  many  stations  are  now  in  opera- 
tion has  made  the  question  of  selectivity 
one  of  vital  importance.  In  the  old  days, 
when  only  a  few  stations  were  sending 
out  their  programs,  it  made  little  differ- 
ence whether  or  not  the  set  was  selective, 
but  today  things  are  changed.  Selectivity 
is  the  watchword.  The  question  of 
distant  reception  has  been  well  taken 
care  of,  and  many  of  the  present  day 
receivers  will  pick  up  programs  from 
coast  to  coast  and  from  Alaska  to  South 
America,  but  if  the  set  is  not  selective, 


this  great  range  is  of  no  particular  value. 

Regeneration  and  radio  frequency 
amplification  have  made  distant  recep- 
tion possible.  Here,  again,  we  find  that 
we  are  back  to  the  old  basic  circuits. 
Radio  frequency  amplification  is  not  new 
but  the  method  of  tuning  it,  the  construc- 
tion of  the  transformers,  neutralizing 
the  feed-back,  and  many  other  improve- 
ments are  to  be  found  in  these  improved 
circuits. 

The  one  bad  feature  of  radio  frequency 
amplification  has  always  been  the  ten- 
dency of  one  stage  to  feed  back  energy 
to  another,  thus  setting  up  undesirable 
oscillations  with  the  resultant  howling 
and  squealing.  Different  methods  of 
overcoming  this  are  found  in  many  of 
the  standard  sets  now  in  use.  The 
neutrodyne,  for  example,  overcomes  this 
difficulty,  by  neutralizing  the  inherent 
capacity  of  the  tube.  By  this  means  all 
the  advantages  of  radio  frequency  ampli- 
fication are  realized  and  distant  recep- 
tion is  easily  obtained. 

Importance  of  Selectivity 

/^\N  the  other  hand,  this  radio  frequency 
"  amplification  of  the  neutrodyne 
would  be  of  little  value  if  the  set  were  not 
selective.  The  regenerative  receiver, 
however,  makes  use  of  the  feed-back 
method  to  gain  amplification.  It  has 
the  bad  feature  of  radiation,  which  is 
one  of  the  greatest  troubles  the  broad- 
cast listener  has  to  contend  with.  Radia- 
tion from  a  nearby  set  will  sometimes 
completely  detune  a  receiver  which  is 
tuned  to  a  distant  station  and  will  cause 
enough  shrieks  and  howls  to  spoil  a  good 
program.  This  is  not  the  fault  of  the 
regenerative  set,  but  rather  the  careless- 
ness of  the  person  operating  it,  for  it  is 
quite  possible  to  so  adjust  it  that  no 
radiation   takes    place. 

Amplification  by  regeneration  is  caused 
by  feeding  back  some  of  the  amplified 
signal  in  the  plate  circuit  to  the  grid. 
This  builds  up  the  strength  of  the  signal 
and  is  really  a  method  of  amplification. 
When  a  signal  strikes  the  grid,  it  is 
rectified  and  amplified  in  the  usual  way. 
A  tuned  plate  circuit  is  employed  and 
when  part  of  the  varying  current  in  the 
plate  circuit  is  fed  back  to  the  grid,  the 
plate  current  is  again  varied.  This  in 
turn  again  increases  the  plate  circuit 
current,  which  is  again  fed  back  to  the 
grid.  This  process  continues  until  the 
signal  becomes  stabilized  and  has  the 
effect  of  prolonging  and  building  up  the 
signal.  The  time  required  for  all  of  this 
building  up  is  so  short  that  it  does  not 
in  any  way  distort  the  signal. 

There  are  many  types  of  regenerative 
circuits  on  the  market  today,  but  they 
all    work   on    the   same   basic   principle. 


RADIO  AGE  for  July,  1925 

But  many  of  them  are  better  than  others, 
due  to  the  fact  that  different  types  of 
inductances  are  used,  and  varying 
methods  of  coupling  the  circuits.  A 
loose  coupling  between  the  primary  and 
secondary  circuits  will  always  give  much 
better  selectivity  than  a  tight  one.  A 
fair  example  of  this  is  seen  in  the  ultra- 
audion  receiver.  Here  there  are  many 
variations.  Sometimes  the  tuning  in- 
ductance consists  of  a  variometer  which 
is  connected  in  series  with  a  variable  con- 
denser. Both  the  inductance  and  the 
condenser  are  variable.  The  same  cir- 
cuit is  often  used  with  a  fixed  inductance 
and  a  variable  condenser.  Either  of 
these  work  very  well,  but  naturally  a 
closer  adjustment  may  be  made  if  both 
the  inductance  and  the  capacity  are 
adjustable. 

Loses  Its  Selectivity 

THIS  type  of  receiver  is  known  to 
have  a  long  range,  but  because  of  the 
direct  coupling  between  the  primary  and 
secondary  circuits,  it  loses  much  of  its 
selectivity.  By  using  a  single  inductance 
in  the  aerial  circuit,  and  placing  it  near 
the  variometer  so  as  to  afford  an  induc- 
tive coupling,  it  still  retains  its  long  range 
and  the  selectivity  is  greatly  increased. 
The  super-heterodyne  is  well  known  for 
long  range  and  selectivity.  In  this 
arrangement  another  bad  feature  of  radio 
frequency  amplification  is  overcome. 
This  is  the  tendency  of  such  transformers 
to  work  at  their  greatest  efficiency  at 
one  certain  frequency  and  the  dropping 
off  of  this  efficiency  as  the  frequency 
varies  from  their  natural  frequency.  In 
this  set,  a  local  oscillator  is  used,  which 
sets  up  oscillations  of  nearly  the  same 
frequency  as  that  of  the  incoming  wave, 
causing  a  beat  frequency  which  is  the 
result  of  the  two,  to  pass  through  the 
radio  frequency  transformers.  As  the 
local  oscillator  is  under  the  control  of  the 
operator,  this  beat  frequency  may  be 
made  the  same  in  any  case,  regardless  of 
the  frequency  of  the  incoming  wave, 
making  it  possible  to  always  work  the 
transformers  at  their  natural  frequency, 
regardless  of  what  the  frequency  of  the 
incoming  wave  may  be.  Thus  the  set 
is  always  working  at  its  greatest  efficiency 
and  even  the  most  feeble  wave  may  be 
picked  up  and  amplified  to  great  volume. 
The  reflex  set  is  peculiar  in  that  it  will 
produce  more  amplification  with  less 
tubes.  This  is  done  by  making  some  of 
the  tubes  do  double  duty.  After  the 
radio  frequency  tubes  have  amplified 
the  signal  and  it  has  passed  through  the 
detector  and  reduced  to  audio  frequency, 
it  is  again  passed  through  the  radio 
frequency  tubes  at  audio  frequency, 
thus  operating  them  at  both  radio  and 
audio  frequency.  This  is  not  only  a 
saving  in  the  original  cost  of  installa- 
tion, but  less  battery  is  also  required  to 
operate  the  filaments  than  would  be 
necessary  in  other  types  of  receivers. 
Many  different  reflex  circuits  have  been 
devised,  but  while  they  differ  in  the 
apparatus  used,  they  all  come  back  to 
the  same  basic  principle. 

Because  of  the  many  deviations  from 
these  basic  circuits,  there  are  hundreds  of 
different  sets  for  sale  and  it  is  no  wonder 


& 


The  Magazine  of  the  Hour 


JEFFERSON 

TRANSFORMERS 


59 


# 


SIFT  OUT  THE  SUMMER  STATIC 

It's  the  season  when  aggravating  radio  imps  seriously 
interfere  with  smooth  reception  on  most  sets — but 
there's  a  way  to  make  your  set  behave  better.  Jefferson 
Transformers  will  bring  in  summer  programs  with 
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facture and  the  benefit  of  greater  experience  by  the 
world's  largest  manufacturers  of  small  transformers 
give  Jefferson  Transformers  the  lead  in  audio  tone 
amplification.  They  will  give  remarkable  results  for 
you  this  summer.  You'll  find  them  at  the  best  radio 
dealers. 

JEFFERSON  ELECTRIC  MFG.  CO. 

501  So.  Green  St. 
Chicago,    Illinois 

Makers  of  Jefferson  Radio  Tube  Re- 
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I 


that  the  uninitiated  beginner  has  a  hard 
time  to  decide  on  which  one  to  purchase. 
In  the  August  issue  of  the  RADIO 
AGE,  all  of  the  basic  circuits  will  be 
shown  in  blueprint  form,  which  has 
made  this  magazine  so  popular  with  the 
fans.  In  this  issue,  which  is  to  be  a  de- 
luxe number,  approximately  eighty  pages 
will  be  given  over  to  this  subject.  Aside 
from  the  blueprints  of  original  circuits, 
many  modifications  and  methods  of 
amplification  will  be  shown,  making  it 
possible  for  one  to  trace  the  history 
of  almost  any  set  in  existence.  A  careful 
study  of  these  circuits  will  in  a  measure 
give  an  idea  of  just  what  changes  they 
have  gone  through  in  the  last  few  years. 
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60 


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Some  of  the  Tricks  Summer 
Static  Plays 

( Continued  from  page  24) 
its  atmosphere  during  that  season.  Un- 
fortunately, no  way  of  avoiding  this 
difficulty  is  known  today.  The  trans- 
oceanic radio  stations  have  to  be  equipped 
with  high  power  apparatus  in  order  to 
work  through  the  bad  periods  of  the  day 
and  year,  although  at  certain  times  of 
the  year  and  day  less  power  may  be 
used,  as  evidenced  by  the  successful 
trans-atlantic  transmission  by  low  power 
amateur  stations. 

For  the  sake  of  clearness,  we  have  so 
far  described  the  cause  of  fading  signals 
as  due  to  obstructions  in  the  path  of  the 
radio  waves.  Actually,  the  radio  clouds 
sometimes  reflect  the  waves,  much  as  a 
mirror  does  a  light  wave,  and  so  very 
peculiar  reception  effects  are  sometimes 
noticed.  Sometimes  the  signals  are  made 
stronger  instead  of  weaker,  sometimes 
they  may  be  lost  altogether,  as  the 
several  effects  of  reflection  and  absorp- 
tion combine. 

And  now,  let  us  consider  that  arch 
enemy  of  radio — Old  Man  Static.  When 
Marconi  first  began  to  receive  messages 
over  distances  of  a  few  miles,  he  noted, 
besides  the  signals  he  was  listening  for, 
noises  which  had  nothing  to  do  with  the 
signals,  and  every  receiving  operator 
since  that  time  has  heard  those  same 
disturbing  and   interfering   noises. 

These  noises  have  been  called  strays, 
or  atmospherics,  or  static,  and  the 
elimination  of  them  is  the  most  impor- 
tant problem  in  radio  communication 
today.  There  are  at  least  two  or  three 
kinds  of  static,  but  the  most  troublesome 
kind  is  the  one  which  is  due  to  ('travelling 
electric  waves,  in  nature  just  like  radio 
waves,  and  caused  by  electrical  dis- 
turbances somewhere  in   space. 

A  LIGHTNING  flash  produces  a 
traveling  electric  wave,  much  like  a 
radio  wave,  and  if  we  can  assume  that 
lightning  flashes,  large  and  small,  are 
occurring  continuously  somewhere,  we 
have  a  reasonable  explanation  of  static. 

We  know  that  static  is  worse  in  the 
Summer  when  variations  in  the  atmos- 
phere are  greater  and  more  frequent. 
Also,  it  is  often  observed  in  the  Winter- 
time that  the  formation  of  snow  causes 
static. 

Without  knowing  definitely  the  origin 
of  this  disturbance,  it  seems  safe  to 
assume  that  the  actions  which  take 
place  in  our  atmosphere,  due  to  the  air, 
the  sun,  sun  spots,  water  vapor,  etc., 
are  responsible  for  the  creation  of  these 
irregular,  irresponsible  and  very  trouble- 
some waves  which  we  call  static.  Since 
they  are  so  much  like  the  radio  waves  in 
nature,  no  way  has  yet  been  found  of 
eliminating  them  completely. 

Progress  has  been  made  in  the  last 
few  years,  however,  and  the  trans- 
oceanic stations  are  much  more  free  of 
this  interference  than  formerly.  The 
problem  of  complete  elimination  of 
static  is  the  most  difficult  one  in  radio, 
and  if  solved,  we  shall  have  a  new  epoch 
in  radio  because  the  power  of  transmitting 
stations  can  be  greatly  reduced  and  the 
reliability    of    communication    increased. 

Tested  and  Approved  by  RADIO  AGE     * 


The  Radio  Spies 

( Continued  from  page  51) 
such  a  position,   to   secure  certain   private  papers, 
papers  and  specifications  and  other  papers  of  the  De 
Forest  Company  and  deliver  the  same  to  him.    She 
declined  to  take  the  position." 

Sylvester  W.  Crowley,  manager  of  the  audion 
division  of  the  De  Forest  Radio  Company,  said  he 
employed  Cecelia  Lambert,  ;•  mentioned  in  the 
Bowlby  and  Jennings  affidavits.  She  was  discharged 
April  16,  1925,  "because  it  was  discovered  that  she 
was  employed  by  the  Radio  Corporation  of  America, 
paid  a  salary  by  them  and  was  making  reports  of 
complainant's  business  secrets  to  that  company." 

Crowley  says  he  was  present  on  April  16, 
1925,  when  Miss  Lambert  admitted  having  furnished 
confidential  reports  to  Harley,  who  assigned  her  to 
work  for  various  concerns,  receiving  wages  from 
her  employer  as  well  as  salary  and  expenses  from 
Harley. 

Mr.  Luce,  President  of  the  De  Forest  Company, 
says  that  for  eleven  years  his  concern  has  been  mak- 
ing, leasing  and  selling  radio  receiving  apparatus 
and  audion  tubes.  For  several  years  the  defendant 
has  been  carrying  on  the  same  business  with  the 
possible  exception  of  manufacturing,  he  declares. 
While  he  has  no  definite,  information  regarding  the 
defendant's  manufacturing  business,  he  says  that  as  a 
result  of  agreements  between  the  defendant,  the 
General  Electric  Company  and  the  Westinghouse 
Electric  and  Manufacturing  Company  the  defend- 
ant was  required  to  buy  part  of  what  it  sells  from 
each  company.  These  three  companies,  with  the 
American  Telephone  and  Telegraph  Company  have 
licensed  each  other  under  various  patents.  He 
adds,  "the  legality  of  this  combination  has  been 
challenged  by  the  Federal  Trade  Commission  and  is 
now  under  judicial  investigation  by  it." 

The  temporary  injunction,  obtained  by  the  De 
Forest  Radio  Company  from  Vice  Chancellor  John 
H.  Backes  of  New  Jersey,  directs  the  Radio  Corpora- 
tion to  appear  in  Chancery  Chambers,  Newark, 
on  May  12,  to  show  cause  why  a  permanent  injunc- 
tion restraining  it  from  obtaining  information 
secretly  from  the  De  Forest  plant  should  not  be 
issued. 

A  recent  issue  of  the  Radio  Guide 
publishes  a  full  page  editorial  on  the 
situation  as  outlined  above.  One  para- 
graph from  this  editorial  follows: 

"Never  in  its  palmiest  days  of  throttl- 
ing and  cut-throat  competition  did  the 
old  Standard  Oil  Company  of  New 
Jersey,  the  original  octopus,  undertake 
anything  as  dastardly,  as  contemptibly 
criminal,  as  the  "dirty  work"  which  the 
Radio  Corporation,  already  cited  in  a 
government  antimonopoly  suit,  is  now 
accused  of." 


Vacuum  Tubes  and  How 
They  Distort 

C  Continued  from  page  18) 
grid  increases,  you  will  find  that  the  line 
is  not  straight,  but  becomes  steeper  over 
quite  a  range,  there  being  a  definite  curva- 
ture  (See  Fig.  1).  Such  a  line  or  curve  is 
spoken  of  as  the  plate  current-grid  voltage 
characteristic  of  the  tube  and  circuit. 
The  more  nearly  straight  it  is,  the  more 
faithfully  does  it  repeat  the  impulses  put 
on  the  grid;  i.  e.,  the  less  distortion  does 
it  introduce.  This  is  a  condition  to  be 
desired,  then.  However,  the  tube  is  to 
be  used  as  an  amplifier. 

The  curvature  of  the  characteristic 
depends  on  the  design  of  the  tube,  and 
in  any  given  tube  may  be  emphasized 
by  the  circuit  with  which  it  is  associated. 

Suppose  we  have  a  tube  circuit  which 
has  curvature  and  we  impress  on  the 
grid  two  electric  currents  of  different 
frequencies.  It  can  then  be  shown 
theoretically  and  is  found  experimentally 
that  there  are  present  in  the  plate  circuit 
currents  of  the  original  frequencies  and 
also  currents  of  frequencies  equal  to 
the  sum  and  equal  to  the  difference  of 
these  frequencies.      In  other  words,  the 


RADIO  AGE  for  July,  1925 

resultant  current  is  not  a  faithful  repro- 
duction of  the  original  impulses,  but 
shows    some    distortion. 

This  is  a  very  useful  thing,  as  may 
be  seen  if  we  apply  the  principle  to  a 
broadcasting  station.  Suppose,  for  ex-. 
ample,  that  we  combine  in  a  tube  cir- 
cuit the  radio  frequency  of  one  million 
cycles  with  a  musical  frequency  of  one 
thousand.  Then,  in  accordance  with 
what  was  said  above,  we  would  have 
set  up  in  the  plate  circuit  the  original 
frequencies  and  the  sum  and  difference 
frequencies;  i.  e.  we  would  have  in  the 
plate  circuit  frequencies  of  1000;  1,000,- 
000;  1,000,000  plus  1000  and  1,000,000 
minus  1000.  The  first  of  these  is  of  too 
low  frequenciy  to  affect  the  radiating 
antenna  of  the  station,  but  the  other 
three,  being  of  suitable  high  frequency, 
would  be  radiated.  It  is  these  three 
waves  of  slightly  different  frequency 
which  would  travel  out  to  your  receiving 
set.  The  middle  one  of  these,  one 
million,  is  called  the  carrier  wave  and 
the  others  may  be  called  the  upper  and 
the  lower  side  waves.  The  three  to- 
gether constitute  the  modulated  wave; 
i.  e.  the  wave  on  which  has  been  im- 
pressed the  message  which  is  to  be 
transmitted.  The  side  waves  or  fre- 
quencies are  the  important  ones,  and  it 
should  be  noted  that  they  were  not 
originally  present,  but  were  brought 
in  only  by  the  distorting  effect  of  the 
tube.  The  mixture  of  the  original  fre- 
quencies is  a  very  intimate  one.  It  is 
more  than  a  mere  addition  of  the  two, 
but   a   scrambling   of  the  two. 

LET  us  now  go  to  the  receiving  set 
where  these  waves  are  picked  up. 
They  finally  reach  a  vacuum  tube.  If 
this  tube  shows  no  curvature  or  dis- 
tortion, it  will  merely  repeat  the  high 
frequency  waves  which  arrived,  but 
these,  in  that  form,  are  of  no  use,  for 
they  are  inaudible.  What  is  desired  is 
a  message  of  the  same  as  the  original 
frequency;  i.  e.  one  thousand.  Obviously 
it  is  going  to  take  something  radical  to 
get  this  from  three  frequencies,  each  at 
or  in  the  neighborhood  of  one  million. 
Suppose,  however,  the  tube  and  its 
circuit  has  distortion  then  by  the  same 
principle  as  given  before;  there  will 
appear  in  the  plate  circuit  currents 
which  are  the  same  as  the  three  high 
frequencies  and  in  addition  there  will 
be  all  the  possible  combinations  of  sum 
and  difference  frequencies.  If  you  will 
set  these  down  yourself,  as  can  be 
easily  done,  you  will  find  quite  an  array; 
in  fact,  there  will  be  twelve  of  them  in 
the  simplest  case.  Most  of  these  will 
not  be  of  use,  but  you  will  find  two 
which  are  of  the  frequency  1000,  the 
original  signal  frequency.  They  repre- 
sent the  difference  between  the  carrier 
of  1,000,000  and  the  side  waves  of 
1,000,000  plus  1000  and  1,000,000  minus 
1000. 

Thus  we  see  that  it  is  as  a  result  of 
its  distorting  characteristic  that  a  tube 
can  first  modulate  a  carrier  frequency 
with  a  message  frequency;  i.  e.  "scram- 
ble" the  two  together  so  that  one  carries 
the  other,  and  then  at  the  receiving 
station  "unscramble"  them  and  give 
us  the  original  message. 


The  Magazine  of  the  Hour 


61 


Hayne$<«riffm 

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A  Portable  Super-Heterodyne 

Designed  by  A.  ].  Haynes 


Complete  description  in  this  month's 
"Radio  Age" 

This  new  Super-Heterodyne  has  been  made 
completely  portable  without  the  least  sacrifice  in 
operating  efficiency.  The  entire  equipment,  set, 
batteries,  loop  aerial  and  loud  speaker  is  contained 
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Reports  from  far  and  near  state  that  this  new  8-tube 
portable  is  daily  giving  reception  fully  equal  to 
standard  laboratory  model  super-heterodynes. 

Right  in  the  heart  of 
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splendid  portable  gets 
distant  stations 

Mr.  J.  K.  Cronin  using  the  set  on  East  36th 
Street,  only  4  blocks  from  station  WMCA,  5 
blocks  from  WGBS,  and  8  blocks  from  power- 
ful stations  WJZ  and  WJY,  brought  in  sta- 
tions KDKA,  WWAD  and  KYW  in  twelve 
minutes  with  all  these  local  stations  broad- 
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Many  larger  super-heterodynes  used  in  the 
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through  this  strong  local  interference. 

Complete  Constructional 
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Construction  of  this  new  Portable  has 
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Complete  dimensions  and  specifications  given 
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Special  combination  price  of 
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Tell  your  friends  about  the  Deluxe 
August  number  of  Radio  Age — ■ 
out  July  15. 


To  be  a  Federal  Radio  Dealer  and  guarantee  your 
success  under  the  "Gould  Plan"  which  allows  you  to 
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RADIO." 

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115  East  13th  St.,  Kansas  City,  Mo. 

*     Tested  and  Approved  by  RADIO  AGE     # 


62 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


To  the  Man  with  an  Idea 

I    offer    a    comprehensive,    expe* 

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Wherein  One  of  Horatio  Alger  s 
Plots  Comes  True 


By  R.  H.  Hopkins 

THE  proper  way  to  tell  about  Mc- 
Murdo  Silver  would  no  doubt  be  to 
say  "Once  Upon  a  Time,"  or,  to  become 
somewhat  more  modern,  we  might  head 
the  dissertation  "From  Nothing  to  Some- 
thing," or  one  might  even  resort  to  the 
time-honored,  and  (we  hope)  buried, 
style  of  Horatio  Alger. 

But  none  of  these  styles  seems  to  fit 
properly,  so  we  will  confine  ourselves 
(not  the  regal,  but  the  editorial  "we") 
to  a  plain  statement 
of  facts  concerning 
the  not  altogether 
uneventful  life  of  a 
young  man  badly 
bitten  with  the  radio 
bug,  who  at  the  age 
of  22  is  the  presi- 
dent of  a  prominent 
radio  concern  and 
whose  name  is  more 
than  well  known  to 
many  thousands  of 
radio  fans. 

Born  in  a  small 
college  town  in  west- 
ern New  York,  the 
son  of  a  college  pro- 
fessor, his  early 
years  were  spent  un- 
eventfully in  caus- 
ing his  fond  parents 
just  a  little  bit  more 
than  the  usual 
amount  of  conster- 
nation, for  at  a  very 
early  age  his 
thoughts  turned  to 
things  mechanical. 
The  result  was  no 
more  than  could  be 
expected.      Many 

peculiar  and  supposedly  original  con- 
trivances made  their  appearance,  most 
of  them  designed  to  provide  a  hearty  and 
stimulating  welcome  for  the  college  stu- 
dents who  called  upon  his  father  in 
search  of  wisdom. 

Frequently  the  searchers  were  dis- 
couraged, but  it  is  interesting  to  the 
casual  observer  of  later  years  to  perceive 


the   executioner's   desire   for  a  negative 
reply,  was  invariably  "yes." 

Practice  Makes  Perfect 

STRANGE  as  it  may  seem,  these  two 
bits  of  instruction  stuck  firmly  in  the 
young  man's   mind.      The  next   day  the 
cook,  called  to  the  back  yard  of  the  family 
residence    by    unearthly   yells,    beheld    a 
strange    sight.      Sitting    astride    a    saw- 
horse  was  a  young  Mexican  boy  hurriedly 
conscripted  for  the  part  of  the  convict. 
His     hands     were 
tightly  tied,   and  a 
very  heavy  rope,  al- 
most   thicker    than 
his  pudgy  arms,  con- 
nected his  unwilling 
neck  with  the  limb 
of  a  small  tree  di- 
rectly   above    him. 
He  was  calling  loud- 
ly upon  all  the  saints 
known  to  him  in  a 
somewhat     unintel- 
ligible    imitation  of 
Spanish.      Next    to 
him  stood  one  of  the 
"Silver  Gang,"  ask- 
ing  loudly   and   re- 
peatedly whether  he 
"joined     or     died." 
The  executioner,  in 
anticipation   of   the 
reply,  held  the  noz- 
zle   of   a    length    of 
garden    hose   in   his 
hand. 

Some  distance 
away,  in  the  wash- 
boiler,  stood  the  in- 
stigator of  this  new 
game,  holding  the 
other  end  of  the  hose 


McMurdo  Silver 


in  one  hand,  while  in  the  other  was 
another  piece  of  hose  which  reached  back 
to  the  gibbet  and  terminated  in  the 
grimy  grip  of  the  assistant  executioner. 
As  the  victim's  cries  were  uttered,  the 
executioner  shouted  them  into  one  hose, 
through  which  they  were  presumably 
transmitted  to  the  ship  at  sea,  simulated 
by  the  wash-boiler.  From  there,  through 
that    these    and    sundry    other    arrange-     the   other    hose,    the   verdict    was    again 


ments  most  frequently  resulted  in  the 
acquisition  of  wisdom. 

Radio  first  entered  McMurdo  Silver's 
consciousness  early  in  1912.  Someone, 
desiring  to  keep  the  young  hopeful's 
mind  well  abreast  of  the  times,  read  him 
an  account  of  "Wireless  Telegraphy"  and 
how  it  enabled  ships  at  sea  to  keep  in 
unbroken  touch  with  the  world  while 
they  were  out  upon  the  bosom  of  the 
bounding  brine. 

At  the  same  time  an  account  was 
also  read,  with  true  relevance,  of 
the  Mexican  Rurales,  a  troop  of  mounted 
police  recruited  from  criminals  by 
the  simple  and  masterly  expedient 
of  catching  one,  putting  a  rope  around 
his  neck,  placing  him  upon  a  horse  all 
ready  to  be  gently  stroked  with  a  whip, 
and  asking  the  individual  so  situated  if 
he  wished  to  become  a  Rurale,  or  if  he 
preferred  to  dismount  from  his  steed 
post-haste  and  remain  in  the  unenviable 
position  of  hanging  by  his  neck  to  a  nice 
tree  limb,  separated  from  it  by  several 
feet  of  rope,  and  from  the  ground  by 
several  more  feet.  The  answer,  unless 
choked  off   by  the   culprit's  emotion,  or 

H-     Tested  and  Approved  by  RADIO  AGE 


shouted  in  a  high  falsetto  to  the  assistant 
executioner,  who  in  turn  put  the  all- 
important  question  to  the  prisoner. 

In  this  way,  wisdom  was  assimilated 
by  the  analytical  mind  of  the  young; 
communication  with  ships  could.only  be 
through  rubber  hose,  since  one  couldn't 
shout  several  thousand  miles.  And  to 
use  "wireless  telegraphy"  one  had  to 
have  a  reason,  which  was  opportunely 
provided  by  the  recalcitrant  son  of  a 
Mexican  villager,  who  might  even  yet 
be  reclaimed  to  the  cause  of  the  law  by 
strong-rope  methods  and  the  marvels  of 
radio. 

Thus  was  the  youth  of  this  young  man 
spent,  alternating  between  the  heights  of 
the  Sierras  and  the  ordered  calm  of  a 
college  town,  the  main  street  of  which 
was  shaded  by  towering  elms  almost  as 
drowsy  as  the  village  itself.  But  this  was 
not  for  long,  and  the  association  of  garden 
hose  and  radio  having  been  demolished 
along  with  other  illusions,  the  big  city 
claimed  our  subject.  There,  more  stren- 
uous pastimes  being  taboo,  radio  was 
taken  up  with  renewed  vigor,  and  a  posi- 
(Turn  to  page  72) 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


63 


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Underground  Radio  from 
Coast  to  Coast 

By  JAMES  E.   SMITH 

President  of  National  Radio  Institute 

Dr.  James  Harris  Rogers,  whose 
achievements  with  underground  trans- 
mission are  far  famed,  has  climaxed  all 
his  tests  by  sending  radio  waves  from 
Hyattsville,  Md.,  to  Los  Angeles,  Calif., 
a  distance  of  3,000  miles.  Signals  at 
Los  Angeles,  according  to  the  report, 
"were  coming  in  finely  with  little  fading." 

This  record  eclipses  all  previous  under- 
ground records  (these  also  having  been 
set  by  Dr.  Rogers'  experiments),  and 
opens  the  way,  according  to  many  leading 
scientists,  to  an  immeasurable  develop- 
ment and  improvement  in  methods  of 
radio  transmission. 

This  achievement  of  coast  to  coast 
transmission  through  the  ground  crowns 
with  success  an  undertaking  which  was 
first  brought  forward  and  attempted  by 
Dr.  Rogers  in  1908.  It  overthrows  the 
dicta  of  men  no  less  eminent  than  Mar- 
coni, who  scoffed  at  the  proposal  to 
radiate  waves  through  the  earths'  crust. 

As  a  direct  result  of  Dr.  Rogers' 
latest  accomplishment,  it  is  now  possible 
that  the  broadcasting  tower,  the  expen- 
sive aerial  extending  sometimes  400  to 
600  feet  in  the  air,  may  become  in  the 
near  future  as  osbolete  and  unnecessary 
as  cable  connections  between  stations. 
The  "aerial"  will  simply  be  taken  out 
and  buried. 

The  "aerial"  which  Dr.  Rogers  uses 
consists  simply  of  4  copper  cables  fifty 
feet  long,  extending  toward  the  four 
points  of  the  compass.  Copper  tubing, 
3-4"  in  diameter,  is  laid  inside  eighteen 
inch  terra  cotta  pipe,  insulated  and 
supported  throughout  by  glass  rods. 
The  pipe  is  buried  3  feet  underground 
outside  the  Rogers  Research  Laboratory 
at  Hyattsville. 

Through  it  the  waves  are  radiated 
into  the  crust  of  the  earth,  and  carried 
through  the  ground — without  atmos- 
pheric disturbance,  without  diminishing 
in  strength  through  the  24  hours  of  the 
day. 

The  earth's  crust  is  the  most  efficient 
medium  for  radio  waves,  Dr.  Rogers 
claims,  and  he  believes  his  experiments 
now  have  disproved  the  Heaviside  theory. 

"Radio  waves  transmitted  through 
the  atmosphere,"  says  Dr.  Rogers, 
"obey  the  laws  of  light — that  is,  travel 
in  a  straight  direction — and  these  atmos- 
pheric waves  are  thus  dissipated,  not 
being  reflected  by  the  Heaviside  mirror. 
The  earth  crust  to  a  much  greater  extent 
retains  the  waves,  and  less  power  is 
required    to    transmit    great    distances." 

During  the  war  Dr.  Rogers  developed 
and  placed  at  the  service  of  the  Govern- 
ment, applications  of  his  theory  which 
made  possible  communication  not  only 
between  submarine  and  submarine,  but 
also  between  submarine  and  shore.  His 
private  station  at  Hyattsville,  using 
his  own  "underground,"  was  pressed 
into  secret  service  by  the  officials  of  the 
Government,  and  received  messages 
clearly  and  strongly  when  the  great 
station  ^t  Arlington  was  hopelessly 
deafened  by  static. 

Should  the  day  ever-  come  when  a  few 
hundred  feet  of  buried  wire  will  supplant 
and  replace  the  towering  and  costly 
aerials  which  now  identify  the  radio 
station,  all  the  laurels  will  be  on  the  brow 
of  this  modest,  indefatigable  man  of 
science,  of  whose  sixty-odd  patents  surely 
none  can  be  of  more  far-reaching  import- 
ance than  this  discovery  which  brings 
the  signals  "in  finely,  at  4  in  the  after- 
noon"— across  the  continent! 

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THE  amazing  expansion  of 
Radio  hasopened  up  hundreds 
of  wonderful  new  positions  on 
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Take  advantage  of  these  wonderful  oppor- 
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One  of  our  recent  graduates,  Emmett  Welch 
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64 


RADIO  AGE  jar  July,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA 

KDLR 

KDPM 

KDYL 

KDZB 

KDZI 

KFAD 

KFAE 

KFAF 

KFAJ 

KFAN 

KFAU 

KFAW 

KFBB 

KFBC 

KFBC 

KFBK 

KFBL 

KFBU 

KFCB 

KFCC 

KFCF 

KFCZ 

KFDD 

KFDH 

KFDJ 

KFDM 

KFDX 

KFDY 

KFDZ 

KFEC 

KFEK 

KFEL 

KFEQ 

KFER 

KFEY 

KFFP 

KFFV 

KFGB 

KFCC 

KFGD 

KFGH 

KFCQ 

KFHA 

KFHH 

KFHL 

KFI 

KFIF 

KFIO 

KFIQ 

KFIU 

KFIX 

KFIZ 

KFJB 

KFJC 

KFJF 

KFJI 

KFJL 

KFJM 

KFJR 

KFJX 

KFJY 

KFJZ 

KFKA 

KFKB 

KFKQ 

KFKU 

KFKX 

KFLB 

KFLD 

KFLP 

KFLR 

KFLU 

KFLV 

KFLX 

KFLZ 

KFMB 

KFMQ 

KFMR 

KFMT 

KFMW 

KFMX 

KFNF 

KFNC 

KFNJ 

KFNL 

KFNV 

KFNY 

KFOA 

KFOC 

KFOJ 

KFOL 

KFON 

KFOO 

KFOP 

KFOR 

KFOT 

KFOX 

KFOY 

KFPC 

KFPL 

KFPM 

KFPR 

KFPT 

KFPV 

KFPW 

KFPY 

KFOA 

KFQB 

KFQC 

KFQH 

KFQP 

KFQR 

KFQT 

KFQU 

KFQW 

KFQY 

KFQZ 

KFRC 

KFRM 

KFRU 

KFRW 

KFRX 

KFRZ 

KFSG 

KFSY 

KFUJ 

KFUL 

KFUM 

KFUO 

KFUP 

KFUQ 

KFUR 

KFUS 

KFUT 

KFUU 

KFUY 


Weatinghouae  Electric  A  Mfg.  Co East  Pittsburgh.  Pa. 

Radio  Electric  Co.. .  Devila  Lake.  N.  D. 

Weatiaghouse  Electric  A   Mfg.   Co Cleveland,   Ohio 

Newhouso    Hotel Salt    Lake    City.    Utah 

Frank    E.    Siefert Bakerafield,    Calif. 

Electrio  Supply  Co Wenatchee.  Wash. 

McArthur   Bros.    Mercantile   Co Phoeniz.   Aril. 

State  College  of  Washington Pullman.  Wash. 

Western    Radio   Corporation Denver.    Colo. 

University   of   Colorado Boulder.   Colo. 

Univeraity    of    Idaho Moscow.    Ida. 

Bobs  High   School Boise,   Idaho 

The  Radio  Den  (W.  B.  Ashford) Santa  Ana,  Calif. 

F.   A.   Buttrey  &   Co Havre.   Mont. 

W.    K.   Azbill San    Diego,   Calif 


....   Presbyterian   Church Tacoma,    Wash. 

Kimball-Upson     Co Sacramento,   Calif. 

Leese  Bros Everett,   Wash. 

The     Cathedral Laramie.  Wyo. 

Nielaon    Radio   Supply   Co Phoenix.   Ariz. 

The   First   Congregational    Church Helena,    Mont. 

Frank  A.  Moore Walla  Walla,  Wash. 

Omaha   Central    High   School Omaha,    Nebr. 

St.     Michaels     Cathedral. Boise.     Idaho 

Univeraity  of   Arizona Tuscon,   Ariz. 

Oregon    Agricultural    College Corvallia,    Oreg. 

Magnolia  Petroleum  Co Beaumont.  Tex. 

First    Baptist    Church Shieveport,    La. 

South    Dakota   State    College Brookinga,    S.    Dak. 

Harry    O.    Iveraon Minneapolis.    Minn. 

Meier  A   Frank   Co Portland,   Oreg. 

Augabury    Seminary Minneapolia.    Minn. 

Winner    Radio    Corp Denver,    Colo. 

J.  L.  Scroggin Oak.  Nebr. 

Auto  Electric  Service   Co Fort  Dodge,    Iowa 

Bunker  Hill  A  Sullivan  Mining  and  Concentrating  Co Kellogg,  Idaho 

First    Baptist    Church Moberly.    Mo. 

Graceland     College Lamoni.  Iowa 

Heidbredor   Radio  Supply   Co Utica,   Neb. 

Louisiana    State    University Baton    Rouge.    La. 

Chickasha  Radio  *  Electric  Co Chickasha.  Okla. 

Leland  Stanford  University Stanford  University,  Calif. 

Crary    Hardware     Co Boone.     Iowa 

Western  State  College  of  Colorado Gunnison,   Colo. 

Ambrose  A.  McCue Neah  Bay.  Wash. 

Penn     College Oakaloosa.   Iowa 

E.   C.   Anthony.   Inc Los   Angelea.   Calif. 

Benaon  Polytechnic  Institute Portland.   Oreg. 

North    Central    High    School Spokane,    Waah. 

First    Methodist   Church Yakima,    Wash. 

Alaska  Electric  Light  &  Power  Co , Juneau.  Alaska 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints   Independence,  Mo. 

Daily  Commonwealth  and  Oscar  A.  Huelsman Fond  du  Lac.  Wis. 

Marshall    Electrical    Co ■  .  -  .Marahalltown.    Iowa 

R.  B.  Fegan  (Episcopal  Church) Junction  City,  Kansas 

National   Radio   Manufacturing  Co Oklahoma  City,   Okla. 

Liberty  Theatre  (E.  E.  Marsh) Astoria.  Oreg. 

Hardsacg    Manufacturing    Co Ottumwa.     Iowa 

University  of  North  Dakota Grand  Forks.  N.  Dak. 

Ashley   C.   Dixon   A   Son Stevensvillo.  Mont,    (near) 

Iowa  State  Teicher'a  College Cedar  Falls.  Iowa 

Tunwall   Radio  Co Fort   Dodge,   Iowa 

W    E.  Branch Fort  Worth,  Texaa 

Colorado  State  Teachers  College  Greeley,   Colo. 

Brinkley-Jonea     Hospital     Association Milford,     Kans. 

Conway  Radio  Laboratories   (Ben   H.  Woodruff) Conway.   Ark. 

The  University  of  Kansas Lawrence,  Kans. 

Weatinghouse  Electric  ft  Manufacturing  Co Hastings.  Nebr. 

Signal  Electric  Manufacturing  Co Menominee.   Mich. 

Paul    E.    Greenlaw.  .■ Franklinton,  La. 

Everett   M.    Foater Cedar    Rapids,    la. 

University    of    Now    Mexico Albuquerciue.  New  Mexico 

Rio  Grande   Radio  Supply   House San   Benito.   Texaa. 

Rev.   A.   T.    Frykman Rockford.    111. 

George  Roy  Clough Galveston.  Tex. 

Atlantic    Automobile    Co Atlantic.    la. 

Christian    Chu-ches Little    Rock,    Ark. 

University  of  Akransaa , Fayetteville.  Ark. 

Morningside   College Sioux   City.   Iowa 

Dr.    George    W.    Young Minneapolis.    Minn. 

M    G.  Srte-en Houghton,  Mich. 

Carleton  College Northfield.  Minn. 

Henry  Field  Seed  Co Shenandoah.  Iowa 

Wooten's  Radio  Shop Coldwnter.  Mias. 

Central  Mo.  State  Teachers  College Warrensburg,  Mo. 

Radio  Broadcast  Ass'n Paso  Roblea.  Calif. 

L    A    Drake  Battery  and  Radio  Supply  Shop Santa  Roaa.  Calif. 

Montana    Phonograph    Co Helena,  Mont. 

Rhodea     Department    Store Seattle.  Waah. 

First    Chriati  in    Church Whittier.     Calif. 

Moberly  Hich  School  Radio  Club Moberly,  Missouri 

LeBlie  M.  Schafhush .  .  Marengo.  Iowa 

Echophone    Radio   Shop •      Long  Beach,  Calif. 

Latter  Day  Saints  University Salt  Lake  City.   Utah 

Rohrer  Elec.   Co •  •  ■  •  •  MarshfielrL   Ore. 

David  City  Tire  A  Electric  Co David  City,  Nebraska 

College  Hill  Radio  Club r,Wir,,hita,l  ?""£" 

Board  of  Education.  Technical  High  School Omaha,  Nebraska 

Beacon  Radio  Service ■  -St.  Paul,  Minn. 

Onrretson  and  Dennis Los  Angeles,  Calif. 

C     C     Baxter Dublin.  Texas 

The   New   Furniture   Co Greenville.  Texaa 

Loa  Ange'es  Co.  Forestry  Dept Loa  Angeles,  Calif. 

Cape  ft  Johnson  Salt  Lake  City,  Utah 

Heintz   ft   Kohlmoos,   Inc San  Francisco,   Calif. 

St.  Johns  M.  E.  Church Carterville    Mo. 

Svmons  Investment  Co Spokane.   Wash. 

The  Princinia ■  ■  ■  StJUuia,   Mo. 

The  Searchlight  Publishing  Co Fort  Worth.  Tex. 

Kidd    Brothers    Radio    Shop .  •  .  .  Taft.    Calif. 

Radio    Service    Co B"  lingame.  Calif. 

G     S     Carson     .Ir Iowa    City.    la. 

Walter   LaFayetto   Ellis Oklahoma    City.    Okla. 

Texas  National  Guard Dennison.  Texaa 

W.  Riker Ho'V  City,   Calif. 

C.  F.  Knierim North  Bend,  Waah. 

Farmers     State    Bank Belden.  Neb. 

Taft     Radio     Co Hollwyood,  Calif. 

City  of  Paris  Drv  Goods  Co San  Francisco.  Calif. 

James   F.   Boland.' ,. Fort  Sill,   Okla. 

Etherical  Radio  Co Bristow,  Okla. 

United  Churches  of  Olympia Olympia.  Wash. 

J.  Gordon  Klemgard Pullman.  Wash. 

The  Electric  Shop Hartington.   Neb. 

Angelua   Temple Los   Angeles.    Calif 


270 
250 
240 
360 
273 
348 
278 
360 
230 
271 
280 
360 
278 
250 
283 
224 
283 
238 
248 
256 
258 
252 
368 
254 
315 
360 
360 


The 


Bla: 


Uric 


Mo 


Hopper  Plumbing  and  Heating  Co Breckenr.rige,  Minn. 

Thomas  Goggan  A  Bros.  Music  Co Galveston,  Tex. 

W.  D.  Corley Colorado  Springs,  Colo. 

Concordia     Seminary St.  Louis.  Mo. 

Fitzsimmnns  General  Hospital Denver,  Colo. 

Julius  Brunton  and  Sons  Co San  Francisco.  Calif. 

H    W    Poory  and  C.  Redfield Ogden,   Utah 

Louis     h.     Sherman Oakland.     Calif. 

University    of    Utah Salt  Lake  City.  Utah 

Colburn    Radio    Labs San    Leandro,    Calif. 

Irvine    M.    Bouchard Butte.  Mont. 


248 

252 

242 

226 

240 

273 

248 

219 

252 

252 

242 

280 

258 

280 

246 

254 

273 

286 

250 

275 

288 

248 
234 

256 

254 

236 

229 

240 

273 

254 

299 

261 

231 

266 

336 

266 

254 

234 

240 

234 

261 

384 

236 

246 

234 

234 

261 

240 

226 

231 

248 

226 

238 

242 

242 

231 

268 

236 

268 

283 

264 

221 

258 

231 

284 

220 

252 

253 

248 

273 

240 

268 

263 

394 

220 

217 

222 

272 

261 

242 

256 

242 

549 

234 

234 

224 

233 


KFUZ 
KFVC 
KFVD 

KFVE 
KrVF 

KFVG 

KFVH 

KFVI 

KFVJ 

KFVK 

KFVL 

KFVN 

KFVO 

KFVS 

KFWA 

KFWB 

KFWC 

KFWD 

KFWF 

KFVR 

KFWH 

KGB 

KGO 

KGU 

KGW 

KGY 

KHJ 

KHQ 

KJR 

KJS 

KLS 

KLX 

KLZ 

KMJ 

KMO 

KNX 

KOA 

KOB 

KOP 

KPO 

KPPC 

KPRC 

KQV 

KOW 

KRE 

KSAC 

KSD 

KSL 

KTCL 

KTHS 

KTW 

KUO 

KUOM 

KWG 

KWKC 

KYO 

KYW 

KZM 

WAAB 

WAAC 

WAAD 

WAAF 

WAAM 

WAAW 

WABA 

WABB 

WABI 

WABL 

WABN 

WABO 

WABQ 

WABR 

WABU 

WABW 

WABX 

WABY 

WABZ 

WADC 

WAFD 

WAHC 

WAMD 

WBAA 

WBAC 

WBAH 

WBAK 

WBAO 

WBAP 

WBAV 

WBAX 

WBAY 

WBBG 

WBBL 

WBBM 

WBBN 

WBBP 

WBBR 

WB8S 

WBBU 

WBBV 

WBBX 

WBBY 

WBBZ 

WBCN 

WBDC 

WBKS 

WBGA 

WBOQ 

WBR 

WB»C 

WBRE 

WBS 

WBT 

WBZ 

WCAD 

WCAE 

WCAC 

WCAH 

WCAJ 

WCAL 

WCAO 

WCAP 

WCAR 

WCAS 

WCAT 

WCAU 

WCAX 

WCAZ 

WCBA 

WCBC 

WGBD 

WCBE 

WCBF 

WCBG 

WCBH 

WCBI 

WCBJ 

WCBM 


Y.  M.  C.  A Virginia.   Minn.     244 

Bensberg's  Music  Co Gamden.  Arkansas     248 

McWhinnie  Electric  Co San  Pedro.  Calif.     202 

Film    Corporation    of  America St.  Louis,  Mo.     245 

Clarence    B.    Juneau Hollywood.    Calif       208 

First   M.   E.   Church Independence.  Kansas     236 

Whan   Radio  Shop   (Herbert  Whan) Manhattan.   Kansas     218 

Headquarters  Troop.   56th    Cavalry Houston,  Texaa     248 

First   Baptist    Church San   Jose ,  Calif.      226 

Sacramento  Chamber  of  Commerce Sacramento,  Calif.     248 

Lt.  Richard  F.  Lussier.  5th  Inf.  U.  S.  A.,  Vancouver  Barracks. Vancou\  er.  Wash.     231 

Carl  E.  Bagley Welcome,  Minn.     227 

F.    M.  Henry Kirksville,  Mo.      226 

Cape  Girardeau  Battery  Station Cape  Girardeau    Mo.  224 

Browning   Bros.   Co Ogden,    Utah      214 

Warner  Bros Hollywood,   Calif.     252 

L.  E.  Wall  and  C.  S.  Myers Upland.  Calif.     211 

Arkansas  Light  &  Power  Co..'. Arkadelphia,  Arkansas     266 

St.  Louis  Truth  Center St.  Louis,  Mo.     214 

Moonlight     Ranch Denver,     Colo.     246 

F.   Wellington   Morse.  Jr Chico,   Calif.      254 

Tncoma   Daily  Ledger Tacoma.   Wash.     252 

General  Electric  Co Oakland,   Calif.      361 

Marion    A.    Mulrony Honolulu.    Hawaii,    Waikiki    Beach     370 

Portland   Morning  Oregonian Portland,   Oreg.     491 

St.   Martins  College   (Reb.  Sebastian  Ruth) Lacy,  Waah.     253 

Times-Mirror    Co Los    Angelea,    Calif.      405 

Louis  Wasmer Seattle  .Wash.     273 

Northwest  Radio  Service  Co Seattle,  WaBh.     384 

Bible  Institute  of  Los  Angeles,  Ino Loa  Angeles,  Calif.     293 

Warner   Brothers    Radio   Supplies   Co Oakland,    Calif.     242 

Tribune    Publishing    Co Oakland.    Calif.      508 

Reynolds      Radio     Co Denver,   Colo.      283 

San  Joaquin   Light  &   Power  Corp Fresno,   Calif.     243 

Love    Electric    Co Tacoma,    Wash.     230 

Loa  Angelea  Evening  Express Los  Angeles,   Calif.     337 

General    Electric    Co Denver,  Colo.      323 

New  Mexico  College  of  Agriculture  A  Mechanic  Arts.  State  College.  N.  Mex.      348 

Detroit    Police    Department Detroit.  Mich.     286 

Hale    Bros San  Francisco,  Calif.     428 

Pasadena  Presbyterian  Church Pasadena.    Calif.     229 

Houston    Post-Dispatch Houston.     Texas     270 

Doubleday-Hill     Electric     Co Pittsburgh.  Pa.     270 

Charles  D.    Herrold San  Jose,    Calif.     226 

V.  C.   Battery   ft  Electric    Co.... Berkeley,  Calif.     275 

Kansas   State   Agricultural   College Manhattan,     Kans.     341 

Post  Dispatch    (Pulitzer  Pub.  Co.) St.  Louis,  Mo  .      645 

Radio  Service   Corp.   of  Utah Salt  Lake  City.   Utah      299 

American  Radio  Telephone  Co..  Inc Seattle.  Wash.      306 

New  Arlington  Hotel  Co Hot  Springs.  Ark.      375 

First  Presbyterian  Church Seattle,   WaBh.      455 

Examiner  Printing  Co San  Francisco.  Calif.     246 

State   Univeraity  of   Montana Missoula.   Montana     244 

Portable    Wireless    Telephone    Co Stockton.  Calif.     248 

Wilson   Duncan   Studios Kansas   City.    Mo.      236 

Electrio  Shop Honolulu,   Hawaii     270 

Westinghouse  Electric  A  Mfg.  Co Chicago.  111.     533 

Preston    D.    Allen Oakland,  Calif.     242 

Valdemar   Jensen New    Orleans ,  La.     2f 3 

Tulano    University New  Orleans  La.      273 

Ohio    Mechanics   Institute Cincinnati,  Ohio     248 

Chicago   Daily   Drovers  Journal Chicago,  111.      286 

I.    R.    Nelson    Co Newark,    N.J.      263 

Omaha    Grain    Exchange Omaha,  Nebr.      283 

Lake  Forest  University Lake  Forest  III.,      227 

Harrisburg    Sporting    Goods    Co Harrisburg,  Pa.      266 

Bangor   Railway  A  Electric  Co Bangor,   Me.     240 

Connecticut    Agricultural    College Sorrs,  Conn.     283 

Ott  Radio.    Inc / LaCroaae.  Wis.      244 

Lake  Avenue  Baptiat  Church Rochester,   N.  Y.     283 

Haverford  College,   Radio  Club Haverford.  Pa.     261 

Scott  High  School.  N.  W.  B.  Foley Toledo.  Ohio     270 

Victor   Talking   Machine   Co Camden.    N.   J.     224 

College  of  Wooster Wooster.   Ohio     234 

Henry    B.    Joy Mt.    Clemena,    Mich.     270 

John   Magaldi.   Jr Philadelphia,   Pa.     242 

Coliseum  Place  Baptiat  Church New  OrleanB,  La.     263 

Allen  T.  Simmona   (Allen  Theatre) Akron,  Ohio     258 

Albert  B.  Parfet  Co Port  Huron.  Mich.      233 

A.  H.  Grebe  A  Co Richmond  Hill.  N.  Y.      315 

Hubbard  and  Co Minneapolis.  Minn.      244 

Purdue     University W.  Lafayette.  Ind.     283 

Clemson   Agric.   College ClemBon   College,   S.   C.     331 

The    Dayton    Co Minneapolis.  Minn.      417 

Pennsylvania  State  Police Harrisburg.  Pa.     275 

James     Millikan     University Decatur,   HI.     360 

Wortham-Carter  Publishing  Co.   (Star  Telegram) Fort  Worth,   Tex.     476 

Erner  ft  Hopkins  Co Columbus.  Ohio     292 

John  H.  Stenger,  Jr Wilkes-Barre.  Pa.     254 

Weatern   Electric   Co New   York,  N.Y.     492 

Irving  Vermilya Mattapoiaett.  Mass.     248 

Grace    Covenant     Presbyterian     Church ,  .  Richmond,  Va.     253 

H.  Leslie  Atlaas Chicago.    III.     226 

Blake.  A.  B Wilmington,  N.   C.     275 

Petoskey  High  School '.Petoskey,    Mich.     246 

Peoplea  Pulpit  Asso Rossville,  N.  Y.     273 

First   Baptist  Church New  Orleans,  La.     232 

Jenks    Motor    Sales  Co Monmouth,  111.     224 

Johnstown     Radio     Co Johnstown,  Pa.     243 

Ruffner    Junior    High    School Norfolk,  Va.     222 

Washington    Light   Infantry   Co.    "B"    118th    Inf Charleston.  B.C.     268 

Noble  B.  Watson Indianapolis.  Ind.     227 

Foster  A  McDoland Chicago.  111.     266 

Baxter  Laundry  Co Gmnd  Rapids,  Mloh.     256 

Bliss  Electrical  School Takoma  Park  Md.     222 

Jonea   Elec.   A   Radio   Mfg.   Co Baltimore   Md.     234 

A.  H.  Grebe  A  Co..  Inc Richmond  Hill.  N.  Y.     236 

Pennaylvania     State     Police Butler,  Pa.     286 

Bell  Radio  Corporation Birmingham,  Ala.     248 

Baltimore  Radio  Exchange Wilkea-Barre,  Pa.     231 

D.   W.   May.     Inc Newark  N.  J.     252 

Southern    Radio   Corp Charlotte.  N.  C.     275 

Westinghouao  E.AM.  Co Springfield.  Maes.     333 

St.  Lawrence   Univeraity Canton.  N.  Y.     280 

Kaufmann    A  Baer  Co.   and  1  he  Pittsburgh  Prea. Pittsburgh,  Pa.     461 

Clyde  R.   Randall New  Orleans.   La.     262 

Entrekin  Electric  Co Columbua,  Ohio     286 

Nebraska  Wealeyan  University University  Place.  Nebr.     283 

St.    Olaf    College Northfie'd,  Minn.     336 

Sanders  A   Stayman  Co. Baltimore  Md.     273 

Chesapeake  A  Potoma  Telephone  Co Washington,    D.  C.      468 

Alamo  Radio  Electric  Co San  Antonio.  Tex.     263 

W.  H.  Dunwoody  Industrial  Institute Minneapolis.  Minn.     280 

State  College  of  Mines Rapid  City.  S.  Dak.     240 

Durham    ft    Co Philadelphia. Pa.      278 

Univeraity  of  Vermont Burlington,  Vt.     250 

Carthage    College Carthage. HI.     246 

Charles  W.  Heibachm Allentown.  Pa.     280 

University  of  Michigan Ann  Arbor,   Mich.     280 

Wilbur     C.     Voliva Zion,  HI.     344 

Uhalt    Radio    Co New    Orleans,  La.     263 

Paul  J.  Miller Pittsburgh.  Pa.     236 

Howard    S.    Williams    (Portable) Pascagoula.  Miaa.     Z68 

University    of    Miss Oxford,  Mias.     Z42 

Nicoll.    Duncan    A    Rush Bemia,  Tennessee     240 

J.  C.   Maua Fennings.  Louisiana     244 

Charles     Swarz .  Baltimore.  Md.      22t» 


RADIO  AGE  for  July,  1925 

Another  Broadcasting  Boom 
Opens 

NSTEAD    of   quieting    down    for    the 
Summer     months,     interest    in  radio 


The  Magazine  of  the  Hour 


65 


I 

broadcasting    is    reported    as    increasing   »pretty  well  covered  by  the  566  stations, 


what  each  potential  radio  entertainer  is 
glad  to  assert,  believing  that  he  is  telling 
the  truth.  Probably  some  of  them  could 
introduce  new  stars,  but  there  are  plenty 
as  it  is.     They  soon  find  that  the  field  is 


by  many  exponents  of  this  art.  At 
least  prospective  broadcasting  station 
owners  are  showing  more  activity  than 
ever  before,  Department  of  Commerce 
records  indicate.  Although  there  are 
566  stations  on  the  air  today,  utilizing 
every  available  broadcast  wavelength, 
there  are  at  least  twenty  applicants  for 
class  B  broadcast  privileges  and  about  a 
hundred  individuals  or  organizations 
are  said  to  be  seeking  licenses  for  class 
A  operation.  Not  all  these  stations  have 
made  formal  application  to  the  Depart- 
ment of  Commerce,  however.  This  is 
not  a  requirement  and  is  seldom  the  usual 
method  of  procedure.  Ordinarily,  a 
prospective  broadcaster  first  leases  a 
site,  then  buys  expensive  equipment 
and  set  it  up  before  he  asks  the  Depart- 
ment if  there  is  a  vacant  air  channel  for 
him.  No  shipping  company  would  buy 
its  beats  and  equipment  before  it  found 
out  if  it  could  get  a  route  and  a  license 
to  do  business;  neither  would  an  auto 
bus  line,  but  in  this  new  game  of  broad- 
casting, some  of  the  more  practical 
essentials  and  necessary  requirements 
seem  to  be  neglected  to  the  cost  of  the 
would-be  radio-phone  station  operators. 

Some  citizens  now  seem  to  realize 
that  there  is  no  more  room  for  Class  B, 
high-power,  stations,  but  the  congestion 
among  the  smaller  class  A  stations,  in 
consequence  of  the  few  channels  assigned 
to  them,  is  worse.  There  are  468  stations 
now,  54  of  them  operating  on  500  watts, 
the  maximum  power  alloted  to  this  class 
and  there  are  dozens  of  them  on  the  same 
wavelength.  As  the  power  increases, 
and  there  is  rumor  that  many  A's  will 
be  permitted  to  go  up  in  power  this 
Summer  in  an  effort  to  overcome  static, 
the  situation  becomes  worse,  from  a 
reception  point  of  view.  With  increased 
power,  they  cover  more  territory  and 
therefore  interfere  with  more  stations, 
just  as  the  higher-powered  B  stations  do, 
even  when  there  are  but  two  or  three  to  a 
wavelength.  In  the  low  A  wave  band  of 
226  meters  for  example,  there  are  six- 
teen stations  now  operating. 

There  is  no  record  kept  of  proposed 
stations  until  formal  applications  are 
filed  with  the  district  radio  supervisor, 
but  from  one  western  supervisor  comes 
the  statement  that  there  are  32  stations 
in  California  alone  planning  to  ask  for 
broadcasting  licenses  as  soon  as  their 
stations  are  completed.  This  official 
can  not  possibily  satisfy  more  than  ten 
or  a  dozen  of  his  prospective  customers, 
many  of  whom  ace  understood  to  have 
already  bought  or  ordered  their  equip- 
ment, despite  the  reiterated  statement 
that  the  broadcasting  lanes  through  the 
ether  are  all  crowded,  and  rights  of  way 


which  are  all  experienced  and  have  their 
own  talent  well  lined  up  and  trained,  not 
to  mention  a  large  following  of  regular 
fans.  Every  one  of  these  stations  in 
operation  is  trying  its  best  to  learn  what 
the  listeners  want  and  to  give  it  to  them; 
many  stations  which  failed  so  to  do,  have 
fallen  by  the  wayside,  their  experiments 
constituting  a  considerable  financial  loss. 

Some  organizations  believe  they  could 
serve  a  special  group  in  the  great  radio 
audience  not  now  furnished  with  what 
they  desire.  In  a  few  instances  this  is 
true,  particularly  as  some  religious  orders 
are   not   on   the   air   in   certain   sections. 

All  Europe,  it  is  pointed  out,  has  not 
so  many  broadcasting  stations  as  there 
are  in  the  United  States  alone.  When 
the  question  of  international  broadcasting 
comes  up  at  the  Paris  or  Washington 
conference,  it  may  be  that  we  shall  have 
to  release  some  of  our  much  desired  and 
used  radio  channels  for  inter-continental 
use,  it  will  be  pointed  out,  and  rightly 
so,  that  we  have  no  more  right  to  the 
205-545  meter  band  than  other  countries, 
and  that  we  should  share  the  wave 
lengths.  If  this  is  the  case,  the  situation 
will  become  worse  unless  a  number  of 
our  stations  drop  out  of  the  game. 

The  increase  in  numbers,  however, 
is  continuing  gradually;  in  April  twenty- 
four  stations,  mostly  smaller  ones,  ceased 
to  broadcast,  but  twenty-seven  new  ones 
opened,  increasing  the  total  on  the  air  May 
1,  by  three  over  the  figure  on  March  1st. 


Russo  and  Fiorito 
Open  WIBO 

STATION  WIBO  came  on  the  air  last 
month,  in  Chicago.  Harry  Geise, 
Director  and  Announcer,  promises  the 
radio  audience 
several  new  and 
novel  surprises 
and  features,  and 
with  the  assist- 
ance of  Dan  Rus- 
so and  Ted  Fio- 
rito, who  have 
already  gained  a 
multitude  of  ra- 
dio friends,  will 
endeavor  to 
please  the  radio 
audience  with 
the  best  pro- 
grams obtain- 
Harry  Geise  able. 


Dan  and  Ted, 
co-conductors  of  the  Oriole  Orchestra, 
formerly  playing  at  the'Edgewater  Beach 
Hotel,  and  Harry  Geise,  known  as  the 
"How-Do- You-Do  Man,"  are  on  the 
air  each  night  to  to  answer  requests. 
WIBO  is  located  at  6310  Broadway, 
Chicago,  the  studio  and  reception  room 
on  the  second  floor,  and  the  operating 
room  on  the  third  floor.  The  studio  is 
are  no  longer  available  except  in  some  of     equipped    with    Celotex    walls,    designed 

unique  manner,  handsomely 
with     perfect     acoustics     for 


the  still  "open  spaces. 

The  fans  seem  to  take  the  view  that 
there  are  enough  broadcasters  now,  and 
that  no  more  should  be  permitted  to  come 
on  the  air  unless  they  can  guarantee 
unique  programs.     This,  however,  is  just 


in  rather 
furnished, 

broadcasting.  The  eighty-foot  towers 
are  completed  and  Philip  I.  Latin,  Chief 
Engineer,  is  working  every  effort  to 
assure  the  public  of  successful  broad- 
casting from  this  station. 

'•     Tested  and  Approved  by  RADIO   AGE     ■ 


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66 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


WCBN  James    P.   Boland Ft.   Benj.    Harrison.    Iod.  266 

WCBQ  First    Baptist    Church Nashville  .Tenn.  236 

WCBR  C.  H.  Messter ; .  .■ Providence,  R.  I.  24g 

WCBT  Clark    University.    Collegiate    Dept Worcester,    Mass.  238 

WCBU  Arnold     Wireless     Supply     Co Arnold,     Pa.  254 

WCBX  Radio  Shop  of   Newark    (Herman   Lubinsky) Newark.   N.   J.  233 

WCCO  Washburn-Crosby    Co Twin    Cities.    Minn.  416 

WCEE  Charles    E.    Erbstein,    Villa    Olivia near    Elgin,    111.  278 

WCK  Stix-Baer-Fuller    D.    G.     Co ' St.    Louis.     Mo.  275 

WCTS  C.   T.   Scherer   Co Worcester,   Mass.  268 

WCX  Free  Press Detroit,  Mich.  516 

WDAE  Tampa  Daily  Times.  ..^ Tampa,  Fla.  365 

WDAF  Kansas    City    Star Kansas    City,     Mo.  365 

WDAG  J.    Laurence    Martin AmariUo,  Tex.  263 

WDAH  Trinity     Methodist     Church     (South) El     Paso,     Tex.  268 

WDAR  Lit  Brothers Philadelphia,  Pa.  394 

WDAY  Radio    Equipment    Corp Fargo.  N.  Dak.  244 

WDBA  FredRay Columbus,  Ga.  236 

WDBB  A.  H.  Waite  &  Co.,  Inc Taunton,  Mass.  229 

WDBC  Kirk,    Johnson    &    Co Lancaster,     Pa.  258 

WDBD  Herman  Edwin  Burns Martinsburg,  W.  Va.  268 

WDBE  Gilham-Seboen  Elec.  Co Atlantic,  Ga.  278 

WDBJ  Richardson  Wayland  Electric  Corp Roanoke,  Va.  229 

WDBK  M.   F.   Broz Cleveland.   Ohio  227 

WDBL  Wise.    Dept.    of    Markets Stevens  Point.  Wis.  278 

WDBN  Electric    Light  &    Power    Co ..Bangor,  Me.  252 

WDBO  Rollins    College    Inc Winter  Park,  Fla.  240 

WDBP  Superior  State  Normal  School Superior.  Wis.  261 

WDBQ  Morton  Rado  Supply  Co Salem.  N.J.  234 

WDBR  Tremont    Temp.e    Baptist    Church Boston,    Mass.  256 

WDBV  The  Strand  Theatre Fort     Wayne,     Ind.  258 

WDBW  The    Radio    Den Columbia.  Tenn.  268 

WDBX  Otto  Baur New  York,  N.  Y.  233 

WDB Y  North    Shore    Congregational     Church Chicago.     111.  258 

WDBZ  Boy  Scouts,  City  Hall Kingstown,  N.  Y.  233 

WDM  Church   of   the   Covenant Washington,    D.   C.  234 

WDOD  Chattanooga   Radio  Co. .  Inc .  Chattanooga,   Tenn .  256 

WDWF  Dutee  Wilcox  Flint.  Inc Cranston,  R.  I.  441 

WD2  J.    L.    Bush Tuscola,    111.  278 

WEAA  F.  D.  Fallain Flint,  Mich.  250 

WEAF  American  Telephone  &  Telegraph  Co New  York,  N.Y.  485 

WEAK  Wichita   Board   of   Trade Wichita,    Kans.  280 

WEAI  Cornell     University Ithaca.  N.  Y.  286 

WEAJ  University  of  South   Dakota Vermilion,  S.  Dak.  283 

WEAM  Borough  of  North  Plainfield   (W.  Gibson  Buttfield) .  .North  Plainfield,  N.  J.  286 

WEAN  Shepard    Co Providence.    R.    I.  273 

WEAO  Ohio    State     University Columbus,  Ohio  293 

WEAR  Goodyear    Tire    and    Rubber    Co Cleveland,  Ohio  389 

WEAU  Davidson    Bros.  Co ..Sioux  City.  Iowa  275 

WEAY  Iris  Theatre  (Will  Horowitz,  Jr.) Houston,  Texas  270 

WEB  Benwood  Co St.  Louis,  Mo.  273 

WEBA  Electric   Shop Highland   Park.   N.   J.  233 

WEBC  Walter  Cecil  Bridges Superior,  Wis.  242 

WEBD  Electrical   Equipment  and  Service  Co Anderson.   Ind.  246 

WEBE  Roy  W.  Walker Cambridge,  Ohio  248 

WEBH  Edgewater  Beach  Hotel,  Chicago  Evening  Post  Station Chicago, III.  370 

WEB  J  Third  Avenue  Railway  Co New  York,    N.  Y.  273 

WEBM  Radio     Corporation     of     America Portable  226 

WEBP  E.  B.  Pedicord New  Orleans.  La.  280 

WEBT  The    Dayton    Coop.    Industrial    High   School Dayton.    Ohio  270 

WEBW  Beloit  College BeloitWis.  283 

WEEI  The  Edison  Electric  Illuminating  Co Boston,  Mass.  475 

WEMC  Barrien  Springs.  Mich.  285 

WEN  R  All- American   Radio   Corporation Chicago.   Illinois  266 

WEW  St.     Louis     University St.  Louis,  Mo.  280 

WFAA  Dallas    News    &    Dallas    Journal Dallas,    Tex.  472 

WFAM  Times  Publishing  Co St.  Cloud.  Minn.  273 

WFAV  University  of  Nebraska,  Department  of  Electrical  Engineering,  Lincoln,  Nebr.  275 

WFBB  Eureka    College Eureka.    111.  240 

WFBC  First     Bapitist     Church Knoxville,  Tenn.  250 

WFBD  Gethspmane  Baptist  Church Philadelphia,  Pa.  234 

WFBE  John  Van  De  Walle Seymour,  Ind.  226 

WFBG  The  Wm.   F.   Cable  Co Altoona,   Pa.  261 

WFBH  Concourse  Radio  Coporation New  York,  N.  Y.  273 

WFBJ  St  John's  University Collegeville.  Minn.  236 

WFBQ  Wynne  Radio  Co Raleigh.  N.  C.  255 

WFBR  Fifth  Inf.  Md.  Nat"'  Guard,  5th  Reg.  Armory Baltimore.  Md.  452 

WFBW  Ainsworth-Gates  Radio  Co Cincinnati.  Ohio  309 

WFBY  Signal  Officer Ft. Ben  Harrison, Ind.  258 

WFBZ  Knox  College Galesburg.  HI.  254 

WFI  Strawbridge  and  Clothier '. Philadelphia,   Pa.  394 

WFKB  Francis  K.  Bridgman Chicago.  111.  217 

WFUV  G.Pearson  Ward Springfield.  Mo.  252 

WFUW  Earl  William  Lewis Moberly,   Mo.  233 

WGAL  Lancaster  Electric  Supply  <fc  Construction  Co Lancaster,  Pa.  248 

WGAQ  YoureeHotel Shreveport,  La.  252 

WGAZ  South  Bend  Tribune South  Bend.  Ind.  360 

WGBB  Harry  n.  Carman.  217  Bedell  St Freeport,  N.  Y.  244 

WGBC  First   Baptist  Church Memphis,   Tenn.  266 

WGBF  Fink    Furniture    Co Evansville,  Ind.  217 

WGBG  Brietenbach's    Radio   Shop Thrifton,    Va.  226 

WGBH  Fall   River  Herald  Pub.  Co (Portable)  209 

WGBI  Frank   S.  Megargee Scranton,  Pa.  240 

WCBK  Lawrence  Campbell Johnstown.  Pa.  248 

WGBM  Theodore  N.  Saaty Providence,  R.  I.  234 

WGBL  Elvria  Radio  A=so.  (Albert  H.  Ernst) Elyria,  Ohio  227 

WGBQ  Stout  Institute Menominee,  Wis.  234 

WGBR  Marsh  field  Broadcasting  Assn Marshfield.   Wis.  229 

WGBS  Gimbel  Brothers New  York,  N.  Y.  315 

WGBT  Furman    University Greenville,  8.  C.  236 

WGBX  University  of  Maine Orono,  Me.  252 

WGBY  Progress  Sales  Co R.  R.  No.  2  218 

WGES  Oak  Leaves  Broadcastng  Station Oak  Park,  111.  283 

WGI  American  R.  &  R.  Co Medford  Hillside.  Mass.  261 

WGN  The    Tribune    Co Chicago,     III.  370 

WGR  Federal  T.  and  T.  Co Buffalo.  N.  Y.  319 

WGY  General    Elec.    Co ' Schenectady  N.  Y.  379 

WHA  University    of    Wisconsin Madison,    Wis.  535 

WHAD  Marquette  University Milwaukee.  Wis.  280 

WHAG  University   of   Cincinnati Cincinnati,   Ohio  222 

WHAH  Hafer  Supply  Co Joplin,  Mo.  283 

WHAM  University  of  Rochester   (Eastman  School  of  Music) Rochester,  N.  Y.  278 

WHAP  II,  Alvin  Simmons,  290  Flatbush  Ave Brooklyn,  N.  Y.  240 

WHAR  Seaside  House Atlantic  City,  N.  J.  275 

WHAS  Courier-Journal  &  Louisville  Times Louisville,    Ky.  399 

WHAV  Wilmington  Electrical   Specialty  Co Wilmington,   Del.  360 

WHAZ  Rensselaer  Polytechnic    Institute Troy,   N.  Y.  385 

WHB  Sweeney    School    Co Kansas    City.    Mo.  365 

WHBA  C.   C.   Shaffer Oil   City.   Pa.  250 

WHBB  Hobel's  Store Stevens   Point,   Wis.  240 

WHBC  Rev.  E.   P.  Graham... Canton.  Ohio  245 

WHBD  Chas.  W.  Howard Bellefontaine,  Ohio  222 

WHBF  Beardslev  Specialty  Company Rock  Island.  Illinois  222 

WHBG  John    S.    Skane Harrisburg,    Pa.  231 

WHBH  Culver    Military    Academy Culver,     Ind.  222 

WHBI  Chesaning    Electric    Co Cheaaning,     Mich.  227 

WHBJ  Lauer  Auto  Co Ft.  Wayne,  Ind.  234 

WHBK  Franklin    St.    Garage,    Inc Ellsworth,    Maine  231 

WHBL  James  H.  Slusser Logansport,  Ind.  220 

WHBM  C.  L.  Carroll.  Portable  Station Chicago.  111.  233 

WHEN  First   Ave.   Methodist   Church St.    Petersburg,   Florida  258 

WHBO  Y.  M.  C.  A.,  Summer  Street Pawtucket.  Rhode  Island  231 

WHBP  Johnstown  Automobile  Co Johsntown,  Pennsylvania  256 

WHBQ  St.  John's  M.  E.  Church  South , Memphis,  Tenn.  233 

WHBR  Scientific  Electric  A  Mfg.  Co.,  3664  Vine  St Cincinnati.  Ohio  216 

WHBS  Edward  Wm.  Locke Mechanicsburg,  Ohio  208 

WHBT  Thomas  W.  Tizzard.  Jr Downers  Grove,   111.  206 

WHBU  B.   L.   Bing's  Sons Anderson,   Ind.  218 

WHBV  Fred  Ray's  Radio  Shop Columbus.  Ga.  244 

WHBW  D.     R.     Kienzle Philadelphia.  Pa.  215 

WHBX  J.    W.   Bowser Punxsutawney,   Pa.  213 

WHBY  St.    Norhert's   College West  De  Pore,  Wis.  250 

WHEC  Hickson  Electric  Co.,  Inc Rochester,  N.  Y.  258 

WHK  Radiovox  Company Cleveland,  Ohio  273 


WHN  George  Schubert New  York,  N.Y.  360 

WHO  Bankers'  Life  Co Dee  Moines,  la.  526 

WHT  Radiophone  Broadcasting  Corporation Deerfield    111.  238 

WIAD  Howard   R.   Miller Philadelphia,   Pa.  254 

WIAK  Journal-Stockman  Co Omaha,  Nebr.  273 

WIAQ  Chronicle     Publishing    Co Marion,  Ind.  226 

WIAS  Home  Electric  Co Burlington.  Iowa  283 

WIBA  The    Capital-Times    Studio Madison,  Wis.  236 

WIBC  L.  M.  Tate  Post.  No.  39.  Veterans  of  Foreign  Ware St.  Petersburg.  Florida  222 

W1BD  X-L  Radio  Service Joliet,  Illinois  2u0 

WIBE  Martinsburg   Radio  Broadcasting  Co Martinsburg,   W.  Va.  210 

W1BF  S.  P.  Miller  Dance  Activities Wheatland.  Wise.  231 

WIBG  St.   Paul's   Protestant  Episcopal  Church Elkins   Park,   Pa.  222 

WIBO  Nelson   Brothers Chicago.    111.  226 

WIBH  "  Elite  Radio  Stores New   Bedford,  Mass.  209 

WIBI  Frederick    B.  Zittell,  Jr Flushing     N.   Y  219 

WIBJ  C.   L.   Carrell   (Portable) Chicago,   111.  216 

WIBK  University  of  Toledo Toledo,  Ohio  205 

WIBL  McDonald  Radio  Co.,  Portable  Station Joliet,  111.  2157 

WIL  Continental  Electric  Supply  Co Washington,   D.  C.  360 

WIP  Gimbel    Bros Philadelphia,    Pa.  509 

WJAB  American    Electric    Co Lincoln,    Nebr.  229 

WJAD  Jackson's    Radio   Engineering   Laboratories Waco.    Texas  352 

WJAG  Norfolk    Daily   News Norfolk,    Nebr.  283 

WJ AK  Clifford    L.    White Greentown,    Iowa  254 

WJAM  D.  M.  Perham Cedar  Rapids,  Iowa  268 

WJAR  The  Outlet  Co.  (J.  Samuels  &  Bro.) Providence,  R.  I.  306 

WJAS  Pittsburgh   Radio  Supply  House Pittsburgh,    Pa.  286 

WJAZ  Chicago    Radio    Laboratory Chicago,    111.  268 

WJBC  Hummer   Furniture  Co LaSalle.   111.  234 

WJBD  Ashland    Broadcasting   Committee Ashland,    Wise.  233 

WJBI  H.  M.  Couch Joliet,  111.  2142 

WJD  Denison    University GraniteviUe,    Ohio  229 

WJJD  Suprrme   Lodge,   Loyal   Order  of  Moose Mooseheart,   111.  303 

WJ  Y  Radio  Corp.  of  Ama '. New  York,  N.  Y.  455 

WJZ  Radio  Corp.  of  Ama New  York.  N.  Y.  455 

WKAA  H.    F.    Paar Cedar    Rapids.    Iowa  278 

WKAD  Chas.  Looff   (Crescent  Park) East  Providence.  R.  I.  240 

WKAP  Dutee     W.     Flint Cranston,     R.     I.  234 

WKAQ  Radio  Corp.  of  Porto  Rico San  Juaa,  P.  R.  340 

WKAR  Michigan     Agriculture     College East     Lansing.     Mich.  285 

WKAV  Laconia    Radio    Club Laconia,    N.    H.  254 

WKBE  K.  &  B.  Electric  Co Webster.  Massachusetts  231 

WKBF  Dutee  Wilcox  Flint Cransten,   Rhode  Island  286 

WKY  Wky    Radio  shop Okla.    City,    Okla.  275 

WLAG  Cutting  A:  Washington  Radio  Corp Minneapolis,  Minn.  417 

WLAL  First  Christian    Church Tulsa, Okla.  250 

WLAP  Wm.  V.  Jordan , Louisville,  Ky.  286 

WLAQ  Arthur  E.  Shilling Kalamazoo,  Mich.  283 

WLAX  Putnam  Electric  Co Greencastle,  Ind.  231 

WLB  University   of    Minnesota Minneapolis,    Minn.  278 

WLBL  Wisconsin  State   Dept.  of   Markets Stevenspoint,   Wis.  278 

WLS  Sears    Roebuck    &    Co. Chicago,    111.  344 

WLW  Crosley    Mfg.  Co Cincinnati.  Ohio  422 

WMAC  J.  Edw.  Page  (Olive  B.  Meredith Cazenovia,  N.  Y.  261 

WMAF  Round     Hills     Radio     Corp Dartmouth,     Mass.  360 

WMAK  Norton  Laboratories Lockport.  N.  Y.  273 

WMAL  Trenton    Hardware   Co Trenton,    N.    J.  256 

WM  AN  First    Baptist    Church Columbus,  Ohio  286 

WMAQ  Chicago     Daily    News Chicago,  111.  447 

WMAV  Alabama    Polytechnic    Institute Auburn,  Ala.  250 

WMAY  Kingshighway    Presbyterian    Church St.    Louis,    Mo.  280 

WMAZ  Mercer    University Macon,    Ga.  261 

WMBB  Trianon    Ball     Room Chicago.   111.  250 

WMBF  Miami    Beach.    Fla.  384 

WMC  Commercial     Appeal Memphis,  Tenn.  503 

WMCA  Hotel  McAlpin  (Greeley  Square  Hotel  Co.) New  York  City  341 

WMH  Ainsworth-Gates     Radio    Co Cincinnati,  O.  321 

WMU  Doubledal-Hill    Elec.    Co Washington,    D.    C.  260 

WN AB  The  Shepard  Stores Boston,  Mass.  250 

WNAC  Shepard  Stores Boston,  Mass.  284 

WNAD  University  of  Oklahoma Norman,    Okla.  258 

WNAL  Omaha    Central    High    School Omaha,  Nebr.  255 

WNAP  Wittenberg  College Springfield.  Ohio  271 

WNAR  First    Christian    Church Butler,    Mo.  230 

WNAT  Lennig  Brothers  Co.  (Frederick  Lennig) \ Philadelphia.  Pa.  254 

WNAX  Dakota   Radio  Apparatus  Co Yankton,   S.   Dak.  248 

WN YC  Dept.  of  Plant  and  Structures New  York,  N.  Y.  526 

WOAC  Page  Organ  Co Lima,  Ohio  260 

WOAE  Midland    College Fremont,    Nebr.  280 

WOAG  Apollo     Theater     (Belvidere     Amusement     Co.) Belvidere,  111.  274 

WOAI  Southern  Equipment  Co San  Antonio,  Texas  392 

WOAN  Vaughn  Conservatory  of  Music  (James  D.  Vaughn) .  .  .  .  Lawrenceburg,  Tenn.  280 

WOAO  Lyradion    Mfg.    Co Mishawaka,     Ind.  369 

WOAR  Lundskow,   Henry   P Kenosha,   Wis.  225 

WOAT  Boyd  M.  Hamp Wilmington,  Del.  360 

WOAV  Pennsylvania    National    Guard,    2d    Battalion,    112th    Infantry Erie,    Pa.  242 

WOAW  Woodmen   of  the   World Omaha,    Nebraska  526 

WOAX  Franklyn  J.  Wolff Trenton.  N.J.  240 

WOC  Palmer    School    of    Chiropractic Davenport,    Iowa  484 

WOCL  Hotel    Jamestown,    Inc Jamestown.    N.    Y.  275 

WODA  James  K.  O'Dea Paterson,  New  Jersey  203 

WOI  Iowa  State  College Ames,  la.  207 

WOO  John    Wanamaker Philadelphia,    Pa.  509 

WOR  L.   Bamberger  and   Co Newark,    N.   J.  405 

WORD  Peoples     Pulpit     Assn Batavia,  111.  275 

WOS  State    Marketing    Bureau Jefferson  City,  Mo.  440 

WOWL  Owl  Battery  Company New  Orleans,   La.  270 

WPAB  Pennsylvania     State     College State  College,  Pa.  283 

WPAC  Donaldson    Radio    Co Okmulgee,  Okla.  360 

WPAJ  Doolittle   Radio    Corp New    Haven.    Conn.  268 

WPAK  North  Dakota  Agricultural  College Agricultural  College,   N.  D.  283 

WPAL  Superior    Radio   &    Telephone    Equipment   Co Columbus,    Ohio  286 

WPAZ  John  R.  Koch  (Dr.) Charleston,  W.  Va.  273 

WPG  The  Municipality  of  Atlantic  City Atlantic  City,  N.  J.  300 

WQAA  Horace    A.    Beale,    Jr Parkersburg.     Pa.  270 

WQAC  E.  B.  Gish Amarillo,  Texas  234 

WQAE  Moore  Radio  News  Station   (Edmund  B.  Moore) Springfield.   Vt.  275 

WQAM  Electrical     Equipment     Co Miami,  Fla.  283 

WQAN  Scranton     Times Scranton,     Pa.  280 

WQAO  Calvary  Baptist  Church New  York,  N.  Y.  360 

WQAS  Prince- Walter  Co Lowell,  Mass.  266 

WQJ  Calumet  Rainbo  Broadcasting  Co Chicago.   HI.  447 

WRAA  The  Rice  Institute Houston,  Tex.  256 

WRAF  The  Radio  Club   (Inc.) Laporte.   Ind.  224 

WR AK  Economy  Light  Co Escanaba,  Mich  256 

WRAM  Lombard  College Galesburg,  111.  244 

WRAQ  St.  Louis  Radio  Service  Co St.  Louis,  Mo.  263 

WRAV  Antioch    College Yellow   Springs,    Ohio  242 

WRAW  Avenue  Radio  Shop   (Horace  D.   Good) Reading,   Pa.  238 

WRAX  Flaxon's    Garage Gloucester    City.    N.    J.  268 

WRBC  Imanuel  Lutheran  Church Valparaiso,  Ind.  278 

WRC  Radio  Corp.  of  Ama Washington,  D.  C.  468 

WREO  Reo   Motor   Car   Co Lansing,   Mich.  286 

WRHF  Washington  Radio  Hospital  Fund Washington,  D.  C.  256 

WRK  Doron    Bros. : Hamilton,     Ohio  360 

WRL  Union    College Schenectady,    N.   Y.  270 

WRM  University   of    Illinois Urbana,    III.  273 

WRR  Police  and  Fire  Signal  Department Dallas,  Tex.  261 

WRW  Tarrytown  Radio  Res.  Labs Tarrytown,  N.  Y.  273 

WSAB  Southeast  Missouri  State  Teachers  College Cape  Girardeau.  Mo.  275 

WSAC  Clemson  Agricultural  College Clemson  College.  S.  C  336 

WSAD  J.  A.  Foster  Co Providence,  R.  I.  261 

WSAG  Loren   Vanderbeck   Davis St.   Petersburg,    Fla.  264 

WSAI  United  States  Playing  Cards  Co Cincinnati    Ohio  325 

WSAJ  Grove  City  College Grove  City,  Pa.  258 

WSAN  Allentown  Call  Pi. Wishing  Co Allentown.  Pa.  229 

WSAP  Seventh  Day  Adventlst  Church New  York,  N.  Y.  263 

WSAR  Doughty  &  Welch  Electrical  Co Fall  River,  Mass.  254 

WSAV  C.  W.  Vick  Radio  Construction  Co Houston.  Tex.  360 

WSAY  Irving  Austin  (Port  Chester  Chamber  of  Commerce).  .  .Port  Chester,  N.  Y.  233 

WSAZ  Chas.  Electric  Shop Pomeroy.  Ohio  258 

WSB  Atlanta  Journal Atlanta.  Ga.  428 

WSKC  World's  Star  Knitting  Co Bay   City.   Mich.  261 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


67 


Advertising  Takes  Its  Place  In 
Radio  Programs 


WASHINGTON:— That  advertising  is 
insidiously  creeping  into  broadcast 
programs  and  that  radio  "entertain- 
ment" will  eventually  become  "thinly 
veiled  publicity,"  is  charged  by  some  of 
the  leading  exponents  of  radio  and 
advertising. 

We  have  all  heard  what  are  virtually 
publicity  talks  on  coffee,  candy,  flour, 
chewing  gum  and  other  commodities, 
through  the  air,  and  also  enjoyed  en- 
tertainment by  playing-card  quartettes, 
automobile-tire  orchestras,  safety  razor 
and  grocery  store  musicians.  The  butch- 
er, the  baker,  the  candlestick  maker  and 
the  whole  of  industry  has  been  broad- 
casting of  late.     What  is  it  coming  to? 

The  question  "whether  advertisers 
should  pay  for  broadcasting"  is  causing 
concern  among  the  broadcasters  and 
national  advertisers,  as  well  as  the  radio 
industry  itself,  but  since  it  will  be  up  to 
the  fans  to  decide  eventually,  a  brief  of 
a  survey  recently  made  by  Albert  E. 
Haase   follows: 

Radio  and  Business 

"The  radio  industry  is  discovering  that 
good  broadcasting  means  good  business, 
and  extraordinary  broadcasting,  extra- 
ordinary business,"  Mr.  Haase  points  out. 
"Conversely,  poor  broadcasting  means 
poor  business.  Many  who  are  in  the  in- 
dustry realize  that  if  the  mad  rush  to 
get  the  advertisers'  dollar  for  the  support 
of  radio  continues,  radio  itself  will  suffer. 
Today,  advertising  agencies  are  offered 
15%  commission  by  a  number  of  broad- 
casting stations  for  business.  One  sales- 
man has  secured  the  advertising  rights 
from  fifteen  stations. 

"On  the  other  hand,  stations  which 
do  not  sell  space  on  the  air  are  besieged 
by  publicity  men  who  seek  to  talk  on 
certain  business  and  collect  from  the 
manufacturers. 

"Overdoing  advertising,  will  kill  radio 
and  at  the  same  time  hurt  advertising,  a 
representative  of  the  Colgate  Co.,  is 
quoted  as  saying.  The  whole  problem  of 
radio  advertising  is  being  studied  by  the 
Association  of  Advertising  Agencies, 
which  already  has  decided  that  the 
present  methods  of  radio  advertising  are 
not  agreeable  nor  desirable  to  fans,  and 
that  the  nuwise  use  of  radio  advertising 
will  be  bad  for  all  advertising." 

So  far  the  American  Tel.  &  Tel.  Co., 
through  WEAF  and  a  chain  of  inter- 
connected stations,  appears  to  be  the 
main  channel  for  radio  advertising.  The 
charges  according  to  Mr.  Haase,  vary 
from  $25  a  minute  for  talks,  and  $250  a 
half  hour  for  entertainment,  from  one 
station,  up  to  $1,600  an  hour  for  enter- 
tainment distributed  through  seven  sta- 
tions. The  advertisers,  of  course,  furnish 
all  the  talent.  Circulation  is  part  of  sales 
talks,  but  figures  are  naturally  only 
estimates.  These  rates  are  not  guaran- 
teed as  fixed,  but  may  be  increased,  unless 


the  Interstate  Commerce  Commission 
should  take  a  hand,  claiming  that  tele- 
phone lines  are  a  public  utility  or  that 
connecting  lines  are  between   states. 

Statements  from  a  number  of  the  rep- 
resentative manufacturers  show  that 
there  is  no  unanimity  of  opinion  against 
paid  radio  advertising,  but  they  all 
believe  in  good  broadcasting. 

Lee  DeForest  believes  that  as  more 
concerns  take  up  radio  advertising,  their 
programs  become  less  interesting  to  the 
public,  that  advertising  is  insidious  and 
becoming  more  flagrant;  and  he  asserts 
that  he  has  actually  become  prejudiced 
against  several  of  the  broadcasters' 
products.  He  looks  forward  to  a  time 
when  the  great  majority  of  programs  will 
be  for  "thinly  veiled  advertising  pur- 
poses." 

Secretary  Hoover  is  opposed  to  censor- 
ship, but  through  the  radio  conferences 
it  has  been  made  known  that  "indirect 
advertising"  only  is  permitted  via  broad- 
casts by  The  Department  of  Commerce. 
However,  Mr.  Haase  sees  possible  Gov- 
ernmental intervention  and  ultimately 
a  decision  from  receiving  set  owners. 

Views  of  concerns  which  have  tried 
paid  advertising  are  interesting.  The 
Eveready  entertainers,  considered  unique 
by  many,  actually  pay  the  National 
Carbon  Co.,  in  good  will.  One  day  3,000 
letters  came  in,  according  to  J.  R.  Craw- 
ford of  that  company.  But  he  does  not 
think  radio  advertising,  even  indirect, 
would  pay  all  types  of  manufacturers, 
except  experimentally. 

As  a  contrast,  Stuart  Peabody  of  the 
Borden  Milk  Co.,  claims  that  two  broad- 
casting trials  failed  to  bring  adequate 
responses.  The  Macy  Co.  failed  to 
derive  substantial  benefits  from  broad- 
casting. But  Nat  Lewis,  owner  of  two 
gift  and  haberdashery  shops,  found 
fashion  talks  via  radio,  which  he  calls 
''publicity,"  better  than  some  other  forms 
of  advertising.  He  received  5,000  letters 
following  one  talk. 

Officials  of  the  United  Retail  Candy 
Stores,  backers  of  the  "Happiness  Boys," 
say  after  fifteen  months  of  broadcasting 
entertainment  stunts,  that  they  feel  it  is 
"publicity"  rather  than  "advertising," 
which  they  use  simultaneously. 

The  Fisher  Co.,  Astor  Coffee  manu- 
facturers, continue  radio  programs  after 
fifteen  months'  trial,  having  received  over 
100,000  communications  from  all  parts  of 
the  country. 

Through  co-operation  with  the  A.  T. 
&  T.  Co.,  the  Victor  Talking  Machine 
Co.  is  said  not  to  pay  for  space,  when  its 
stars  sing  and  play.  It  is  studying  the 
results,  however,  and  will  soon  report  on 
broadcasting.  Advertising  experts  feel 
that  radio  has  a  time  limit  and  that  its 
circulation  is  uncertain,  compared  to 
other  mediums;  they  believe  it  is  prob- 
ably an  accessory. 
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A  62 -page 
Blueprint  Section 

in  the  August 
RADIO    AGE 


68 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


WSMB 

WSMH 

WSMK 

WSOE 

WSRF 

WSTA 

WSUI 

WTAB 

WTAC 

WTAL 

WTAP 

WTAQ 

WTAR 

WTAS 

WTAT 


CFAC 

CFCA 

CFCF 

CFCH 

CFCJ 

FCKC 

CFCN 

CFCQ 

CFCR 

CFCT 

CFCU 

CFCW 

CFDC 

CFHC 

CFLC 

CFQC 

CFRC 

CFUC 

CFXC 

CFYC 

CHAC 

CHBC 

CHCB 

CHCD 

CHCE 

CHCL 

CHCM 

CHCS 

CHIC 

CHNC 


PWX 

2DW 

2AB 

20K 

2BY 

2CX 

2EV 

2TW 

2HC 

2LC 

2KD 

2MN 

2MG 

2JD 


2LO 
51T 
5WA 
6BM 
2ZY 


Saenger  Amusement  Co.  and  Maison  Blanche  Co New  Orleans,  La.  319  WTAU 

Shsttuck  Music  House Owosso.  Mich*.  240  WTAW 

S.   M.   K.   Radio  Corp Dayton,   Ohio  275  WTAX 

School  of  Ensineerine Milwaukee.  Wis.  246  WTAZ 

Hardem  Sales  and  Service Broadlands,  HI.  233  WTHS 

Camp  Marienleld Chesham.  N.  H.  229  WTG 

State  University  of  Iowa Iowa  City,  Iowa  498  WTIC 

Fall  River  Daily  Herald  Publishing  Co Fall  River.  Mass.  248  WTX 

Penn  Traffic  Co Johnstown.  Pa.  360  WW  AD 

Toledo  Radio  &  Electric  Co Toledo.  Ohio  252  WWAE 

Cambridge  Radio  &  Electric  Co Cambridge.  III.  242  WWI 

8.  H.  Van  Gordon  &  Son Osseo.  Wis.  220  WWJ 

Reliance    Electric    Co Norfolk.  Va.  280  WWL 

Charles   E.   Erbstein Elgin,   HI.  303  WWOA 

Edison  Electric  Illuminating  Co (portable)   Boston,   Mass.  244 


Ruegg  Battery  &  Electric  Co Tecnmseh.  Nebr. 

Agricultural  &  Mechanical  College  of  Texas College  Station,  Tel. 

Williams    Hardware    Co Streator,  111. 

Thomas  J.   McGuire Lambertville,   N.  J. 

Flint    Senior    High    School Flint.   Mich. 

Kansas  State  Agricultural  College Manhattan.  Kans. 

Travelers  Insurance  Co Hartford,  Conn. 

H.  G.  Saal  Co Chicago,  HI. 

Wright  &  Wright  (Inc.) Philadelphia.  Pa. 

The  Alamo  Ball  Room Joliet.  HI. 

Ford   Motor   Co Dearborn,   Mich. 

Detroit    News     (Evening    News    Assn.) Detroit,    Mich. 

Loyola    University New    Orleans,    La. 

Michigan  College  of  Mines Houghton.  Mich. 


Canadian  Stations 


Calgary    Herald Calgary,  Alberta  430 

Star  Pub.  &  Prtg.  Co Toronto.  Ontario  400 

Marconi  Wireless  Teles.  Co.  Canada Montreal.  Quebec  440 

Abitibi  Power  &  Paper  Co Iroquois  Falls,  Ont.  400 

La  Cie  de  L'Evenement Quebec.   Quebec  410 

Radio   Supply   Co - Edmonton,    Alberta  410 

W.  W.  Grant  Radio  (Ltd.) Calgary,  Alberta  440 

Radio   Specialties    (Ltd.) Vancouver,   B.   C.  450 

Laurentide   Air   Service Sudbury,    Ont.  410 

Victoria    City   Temple : Victoria,    B.    C.  410 

The  Jack  Elliott  Radio  Limited : Hamilton,  Ont.  410 

The  Radio  Shop London.    Ont.  420 

Sparks     Co Nanaimo,  B.  C.  430 

Henry   Birks    &   Sons Calgary,    Alta.  440 

Chas.   Guy   Hunter 651   Adelaide   St.,    London,   Ont.  410 

The  Electric  Shop   (Ltd.) Saskatoon,   Saskatchewan  400 

Queens     University Kingston,  Ontario  450 

University    of    Montreal Montreal,    Quebec  400 

Westminster   Trust   Co New   Westminster.    B.   C.  440 

Victor   Wentworth    Odium Vancouver,    B.    C.  400 

Radio    Engineers Halifax.    Nova    Scotia  400 

Albertan   Publishing  Co Calgary,    Alberta  410 

Marconi    Company Toronto,  Ont.  410 

Canadian   Wireless  &  Elec.  Co Quebec.  Quebec  410 

Western  Canada  Radio  Sup.  (Ltd.) ■. Victoria,  B.  C.  400 

Vancouver  Merchants  Exchange .- Vancouver,  B.  C.  440 

Riley  &  McCormack Calgary.  Alberta  415 

The   Hamilton   Spectator Hamilton,   Ont.  420 

Northern    Electric    Co Toronto,    Ont.  356 

Toronto    Radio     Research Toronto.  Ont.  350 


CHXC  J.    R.    Booth Ottawa,  Ont. 

CH YC  Northern  Electric  Co Montreal,   Quebec 

CJBC  Jarvis   Baptist   Church Toronto,   Ont. 

CJCA  Edmonton  Journal Edmonton,  Alberta 

CJGC  London  Free  Press  Prtg.  Co London,  Ont. 

CJCD  T.    Eaton    Co Toronto,    Ont. 

CJCE  Snrott-Shaw    Radio    Co Vancouver,    B.    C. 

CJCF  The    News    Record Kitchener,    Ont. 

CJC!  Maritime  Radio  Corp St.  John,  New  Brunswick 

CJCK  Radio  Corp.  of  Calgary Calgary.  Alta. 

CJCM  J.  L.  Phillipe Mont  Joli,  Quebec 

GJCN  Simons  Agnew  &  Co Toronto.   Ont. 

CJSC  Evening    Telegram Toronto,  Ont. 

CKAC  La  Presse  Pub.  Co Montreal,  Quebeo 

CKCD  Vancouver  Daily  Province Vancouver,   B.  C. 

CKCE  Canadian  Independ.  Telephone  Co Toronto,  Ont. 

CKCK  Leader    Pub.    Co Regina,    Saskatchewan 

CKCO  Ottawa    Radio    Association Ottawa,   Ont. 

CKCX  P.  Burns  &  Co Calgary.  Alberta 

CKLC  Wilkinson   Electric   Company Calgary,  Alberta 

CKOC  Wentworth    Radio    Supply    Co Hamilton,    Ont. 

CNRA  Canadian  National  Railways Moncton.  N.  B. 

CNRC  Canadian  National  Railways : Calgary,  Canada 

CNRE  Canadian  National  Railways Edmonton,  Alta. 

CNRM  Canadian  National  Railways Montreal.  P.  Q. 

CNRO  Canadian  National  Railways Ottawa,  Ont. 

CNRR  Canadian  National  Railways Regina,  Sash. 

CNRS  Canadian  National  Railways Saskatoon,  Sash. 

CNRT  Canadian  National  Railways Toronto.  Ont. 

CNRW  Canadian  National  Railwaya Winnipeg,  Man. 


Cuban  Stations 


242 

280 
231 
283 
218 
273 
323 
268 
360 
242 
273 
352 
260 
244 


435 
410 
312 
455 
430 
410 
420 
295 
400 
316 
430 
410 
430 
430 
410 
450 
420 
440 
440 
400 
410 
313 
357 
455 
410 
430 
312 
329 
357 
384 


Cuban  Telephon   Co Habana  400  2K 

Pedro  Zayas Habana  300  2HS 

Alberto  S.  de  Bustamante Habana  240  20L 

Mario  Garcia  Velez Habana  360  2 WW 

Frederick  W.  Borton -. Habana  260  5EV 

Frederick  W.  Borton Habana  320  6KW 

Westinghouse  Elec.  Co Habana  220  6KJ 

Roberto  E.  Ramires Habana  230  6CX 

Heraldode  Cuba Habana  275  6DW 

Luis  Casas Habana  250  6B  Y 

E.  Sanchez  de  Fuentea Habana  350  6AZ 

Fausto  Simon. Habana  270  8BY 

Manuel  G.  Salas Habana  280  8FU 

Raul  Pare,  Falcon ' Habana  150  8DW 


Alvara  Dasa Habana     200 

Julio  Power Habana     180 

Oscar  Collado Habana,     290 

Amadeo  Saenz Habana     210 

Leopoldo  E.  Figueroa Colon 

Frank  H.  Jones Tuinuou 

Frank  H:  Hones Tuinueu 

Antonio  T.  Figueroa Cienfiegoa 

Eduardo  Terry Cienfiegoa 

Jose  Ganduxe Cienfiflgot 

Valentin  Ullivarri Cienfiegoa 

Alberto  Ravelo Stgo.  de  Cuba     250 

Andres  Vinnet Stgo.  de  Cuba     225 

Pedro  C.  Andus Stgo.  de  Cuba     275 


360 
340 
275 
170 
225 
300 
200 


European  Broadcasting  Stations 

British  Stations 


London 365  5NO 

Birmingham 475  5SC 

Cardiff .350  2BD 

Bournemouth 385  6SL 

Manchester 375 


Newcastle ■ 400 

Glasgow 420 

Aberdeen 492 

Sheffield  (relay  station) 303 


French  Stations 


End  your  Radio  Troubles  for  30c  in  Stamps 


We  have  laid  aside  a  limited  number  of  back  issues  of  RADIO  AGE  for  your  use. 
in  these  volumes.  Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired, 
store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 

January,  1924 

— Tuning   Out  Interference — Wave   Traps — EUminators 

— Filters. 

— A  Junior  Super-Heterodyne. 

— Push-Pull  Amplifier. 

— Rosenbloom  Circuit. 

March,  1924 

—An  F.ight-Tube  Super-Heterodyne. 

— A  simple,  low  loss  tuner. 

— A  Tuned  Radio  Frequency  Amplifier. 

— Simp'e  Reflex  Set. 

April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated) 

— A  Ten-Dollar  Receiver. 

— Anti-Body  Capacity  Hookups. 

— Reflexing  the  Three-Circuit  Tuner. 

—Index  and  first  two  installments  of  Radio  Age  Data  Sheets. 

May,  1924 

— Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

— Important   Factors   in    Constructing   a   Super- Heterodyne. 

— A  Universal  Amplifier. 

—A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne 

— Radio  Age  Data  Sheets. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 

— Operating  Detector  Tube  by  Grid  Bias 

— A  Three-Tube  Wizard  Circuit. 

— Data  Sheets. 

August,  1924 

— Breaking  Into  Radio  Without  a  Diagram. 

—The  English  4-Element  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 

RADIO  AGE,  Inc. 


Below  are  listed  hookups  to  be  found 
The  supply  is  limited,  so  enrich  your 


September,  1924 

— How  Careful  Mounting  Will  Improve  Reception. 

— One  Tuning  Control  for  Hair's  Breadth  Selectivity. 

— Four  Pages  of  Real  Blueprints  of  a  New  Baby  Heterodyne 

and  an  Aperiodic  Variometer  Set. 
— Data  Sheets. 


October,  1924 

— An  Easily  Made  Super-Het. 
— Two  Radio  and  Two  Audio  for  Clear  Tone. 
— A  Simple  Regenerative  Set. 
—The  Ultradyne  for  Real  DX. 
— Real  Blueprints  of   a    3-Tube    Neutrodyne 
Reflex  Set. 


— Blueprints    of   a    Single   Tube    Loop    Set    and    a    Capacity 

Feedback    Receiver. 
— A  3-Tube  Low  Loss  Regenerator. 
— Mastering  the  3-Circuit  Tuner. 


December,  1924 

— Blueprints  of  a  New  S-Tube  Super-Heterodyne. 
— How  to  Make  a  Receiver  that  Minimizes  Static. 
— A  Trans-Atlantic  DX  Receiver. 

— How  to  Make  a  Home  Made  Battery  Charger  and  a  Loud 
Speaker  at  a  Small  Cost. 

January,  1 925 
— A  Reflexed  Neutrodyne 
— A  Six  Tube  Super-Het. 
— An  Efficient  Portable  Set. 
—A  Tuned  Plate  Regenerator. 
—Making  a  Station- Finder. 


February,  1925 

— A  Sure  Shot  Super-Het. 

— A  Three  Circuit  Regenerator. 

— -A  Real,  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex. 


March,  1925 

— A  Permanent  Super-Het. 
—A  5-Tube  R.  F.  Receiver. 
— How  to  Wind  Low  Loss  Coils. 
— A  Short  Wave  Receiver 

— Blue  Prints  of  a  Two-Tube  Ultra  Audion  and  a  Re- 
generative Reflex. 

April,  1925 

—A  3-Tube  Portable  Set 

— "B"  Voltage  from  the  A.  C.  Socket 

— An  Amplifier  for  the  3-Circuit  Tuner 

— Blueprints  of  a  Five-Tube  Radio  Frequency  Receiver 

May.  1925 

— A  "Quiet"  Regenerator. 
— A  Power  Supply  Receiver. 
— How  to  Make  a  Tube-Tester. 

— A  Unique  Super-Het  and  an  Improved  Reinartz. 
— A    Six    Tube    Portable    Receiver   Hlustrated    with    Blue- 
June,  1925 

— Reducing  Static  Disturbances 
— A  Seven-Tube  Super- Heterodyne 
— The  Double  Grid  Tube  in  Ordinary  Sets 
— Browning- Drake  Receiver 

— Overcoming  Oscillations  "in  the  Roberts  Receiver 
— An  Ideal  Set  in  Practical  Form 
— Soldering  Secrets 


500  N.  Dearborn  St.,  Chicago 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


69 


WITH 


URERS 


Dry  Cell  Tests  Held 
for  First  Time 

ON  May  10,  from  the  Great  Lakes 
Naval  Training  Station,  Great  Lakes, 
111.,  the  first  tests  in  history  were  made 
from  an  airplane  in  flight,  using  the  new 
37  meter  radio  transmitter  and  receiver 
operated  by  dry  cells  only. 

Heretofore,  all  airplane  radio  equip- 
ment has  had  its  source  of  power  from  a 
small  generator  which  was  driven  through 
a  fan-shaped  propeller  by  the  force  of 
the  wind.  In  other  words,  when  the  engine 
and  the  airplane  were  out  of  commission 
— so  was  the  radio.  This  new  transmitter 
which  is  being  tested  is  the  first  of  its 
kind  and  is  one  of  the  transmitters  which 
will  be  used  by  the  MacMillan  Polar  Ex- 
pedition which  sails  from  Boston,  Bun- 
ker Hill  Day,  June  17,  under  the  auspices 
of  the  National  Geographic  Society. 

The  value  of  this  type  of  equipment  can 
be  immediately  realized  when  it  is  remem- 
bered that  the  airplanes  that  are  to  ac- 
company the  MacMillan  Expedition 
manned  by  U.  S.  Navy  personnel,  under 
the  command  of  Commander  R.  E.  Byrd, 
U.  S.  N.,  will  fly  over  that  great  unex- 
plored area  lying  between  Point  Barrow 
and  the  North  Pole,  in  quest  of  new  land. 
Should  a  landing  be  forced,  this  type  of 
apparatus,  if  efficient,  will  be  able  to 
communicate  after  the  airplane  itself  is 
out  of  commission,  and  the  flyers  will  be 
able  to  call  for  help  from  the  planes  held 
in  reserve  back  at  the  advance  base  of 
Axel  Heiberg  Land. 

The  Zenith  Radio  Laboratory  an- 
nounced that  the  tests  made  at  Great 
Lakes  Naval  Training  Station  on  37 
meters  were  not  satisfactory,  as  the  great- 
est distances  at  which  they  were  heard 
were  Newton,  Iowa,  and  Minneapolis. 
Failure  to  reach  greater  distances  is 
attributed  to  the  fact  that  the  amateurs 
of  the  United  States  were  not  properly 
advised  of  the  time  at  which  these  tests 
would  take  place. 

Campaign  for  Jewett 

E.  H.  WILKI NSON and T.  F.  W.  Meyer, 
General  Manager  and  General  Sales 
Manager,  respectively,  for  the  Jewett 
Radio  and  Phonograph  Co.,  Pontiac, 
Michigan,  have  returned  to  the  factory 
after  an  extended  trip  through  the  East 
putting  the  finishing  touches  on  the  new 
distributors'  and  dealers'  franchise  plan 
in  that  territory  which  has  been  under 
way  for  several  months. 

The  Jewett  slogan,  "Fair  prices,  rigidly 
maintained"  must  be  very  strictly 
adhered  to  under  this  new  system,  be- 
cause every  dealer  handling  Jewett 
products   throughout   the   country   must 


Stewart-Warner  Radio, 
Model  305 

The  Stewart- Warner  Speedometer  Cor- 
poration, 1826  Diversey  Parkway,  Chi- 
cago has  placed  on  the  market  a  com- 
plete ensemble  of  matched  radio  units. 
This  ensemble  consists  of  the  line  of 
Stewart- Warner  Radio  Instruments;  the 
Stewart- Warner  Reproducer  especially 
built  to  give  perfect  harmony  with  Stew- 
art-Warner Instruments;  Stewart-War- 
ner Radio  Tubes,  designed  to  give  beau- 
tiful tone  quality;  Batteries,  Aerial  and 
Ground  Equipment. 


The  Stewart- Warner  Instrument  shown 
is  Model  305 — a  five  tube  set  in  which 
is  incorporated  the  U.  S.  Navy  Circuit. 
There  are  three  tuning  controls,  mounted 
on  a  sloping  front  panel.  The  cabinet 
is  finished  in  dark  walnut. 

In  this  instrument,  the  special  Navy 
tuned  radio  frequency  circuit  has  been 
developed  to  a  high  stage  of  perfection, 
and  the  set  is  especially  suited  to  opera- 
tion by  men  or  women  without  technical 
knowledge  or  training. 

The  Stewart- Warner  Reproducer  is 
built  by  the  Stewart- Warner  Speedo- 
meter Corporation  of  Chicago,  especially 
for  use  with  Stewart- Warner  Radio  In- 
struments. This  Reproducer  is  so  de- 
signed and  constructed  that  it  covers  the 
entire  musical  scale  with  full,  rich  tone 
volume  and  without  distortion  or  scratch- 
ing noises.  The  horn  is  made  from  fibre 
by  special  process  and  is  vulcanized  on 
its  outer  surface.  The  core  of  the  horn 
is  allowed  to  remain  soft  -which  absolutely 
prevents  the  horn  from  vibrating  at 
any  note. 

The  Stewart- Warner  Reproducer  is 
finished  in  a  dark  walnut,  leather-like 
surface,  and  stands  on  a  metal  base  which 
is  deep  green  with  gold-bronze  high- 
lighting. This  Reproducer  harmonizes 
perfectly  with  the  walnut  cabinet  work 
of  Stewart- Warner  Radio  Instruments. 


come  well  recommended  as  to  their  sta- 
bility by  a  Jewett  Distributor,  or  one  of 
the  factory  district  representatives  in  the 
field,  it  is  announced. 

The  dealer  will  be  benefited  in  this 
sa'me  respect  by  knowing  that  his  cus- 
tomer cannot  buy  a  Jewett  product  from 
any  but  another  authorized  dealer  who 
is  holding  to  the  standard  Jewett  prices. 


Freshman  Announces  New 
Sales  Policy 

The  Chas.  Freshman  Co.,  Inc.  of 
New  York  has  just  announced  its 
sales  policy  for  the  coming  season.  This 
concern,  manufacturers  of  the  line  of 
Freshman  Masterpiece  Receiving  Sets, 
has  decided  to  eliminate  the  jobber  and 
distributor  in  the  sale  of  their  products. 
Freshman  Masterpiece  Sets  will  be  sold 
to  Authorized  Freshman  Dealers,  care- 
fully selected,  and  granted  an  exclusive 
franchise  in  their  territory.  In  towns  of 
approximately  25,000  and  under,  one 
representative  dealer  will  be  appointed 
to  exclusively  handle  the  line,  and  in 
larger  cities,  additional  dealers  will  be 
granted  franchises  in  proportion  to  the 
population  and  trading  area.  A  staff 
of  salesmen  is  now  at  work  signing  up 
dealers  to  the  Freshman  Masterpiece 
Contract,  which  assures  dealers  of  abso- 
lute protection,  as  far  as  stability  of  prices 
is  concerned;  also,  all  business  from  each 
individual  dealers'  territory  will  be  credi- 
ted to  him.  In  this  way,  the  appointed 
dealers  will  be  practically  direct  factory 
representatives    of    Freshman. 

The  Freshman  Company  enjoyed  re- 
markable success  with  their  one  model, 
the  original  Freshman  Masterpiece,  dur- 
ing the  last  year.  The  fact  that  with  one 
model,  priced  at  $60.00,  over  125,000 
sets  were  sold  from  July  1924  until  Feb- 
ruary 1925,  speaks  highly  for  the  tre- 
mendous hold  this  product  has  taken 
with  the  radio  public.  With  the  realiza- 
tion that  the  trend  in  radio  buying  is 
leaning  strongly  towards  furniture  effects, 
the  company  has  placed  a  complete  line 
of  Freshman  Masterpiece  Receivers  on 
the  market,  ranging  in  price  from  a 
Five  Tube  Radio  Frequency  Set,  in  a 
massive  cabinet  with  sloping  panel  at 
$39.50,  up  to  the  Franklin  Console,  a 
dignified  piece  of  furniture  of  vigorous 
lines  and  fine  proportions,  made  entirely 
of  genuine  solid  mahogany  by  the  manu- 
facturers of  the  highest  class  talking 
machine  Company  in  the  world  at  $115. 
The  Franklin  Console  is  composed  of  two 
separate  and  distinct  units,  one  of  which 
is  a  receiving  set  with  built-in  loud 
speaker,  and  the  other  the  console  for 
batteries  and  accessories — everything  be- 
ing concealed. 


New  "Hercules"  Masts 

SW:  HULL  &  Company,  2048  East 
•  79th  St.,  Cleveland,  Ohio,  announce 
a  new  series  of  "Hercules"  Aerial  Mast. 
These  masts  are  made  in  three  standard 
lengths,  20  ft.,  40  ft.,  and  60  ft.,  all  steel 
construction. 

All  masts  are  made  of  a  special  angle 
construction  that  gives  great  strength 
and  light  weight,  thus  making  a  rugged 
mast  easily  erected,  at  the  same  time 
presenting  a  pleasing  appearance  by  its 
graceful  lines.  (Turn  to  page  72) 


70 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


CLASSIFIED  ADVERTISEMENTS 

If  you  have  anything  to  buy  or  sell,  don't  overlook  the  value  of  RADIO  AGE'S  classified 
advertisements.    Many  such  messages  have  paved  the  way  to  independent  incomes. 

The  classified  advertising  rates  are  but  ten  cents  per  word  for  a  single  insertion.  Liberal 
discounts  are  allowed  on  three,  six  and  twelve-time  insertions,  of  five,  fifteen  and  thirty  per  cent 
respectively.  Unless  placed  through  an  accredited  advertising  agency,  cash  should  accompany 
all  orders.  Name  and  address  must  be  included  at  foregoing  rates  and  no  advertisement  of  less 
than  ten  words  will  be  accepted. 

All  classified  ads  for  the  August  issue  must  be  sent  in  by  July  1. 


AGENTS  WANTED 


FORDS.  60  n 
proven  such  r 
antees  to  incr 
boiling  in  sum 
Decarbonizes 


<  one  gallon  of  Gas.      It  has  been 

can   be   made.      AIRLOCK  gaar- 

is  mileage;  also  prevents  radiator 

'  freezing  in  winter.     Cools,  Fuels, 

motor.        Splendid     territory 

t  703G,  Willow  Street, 


RADIO — Join  our  sales  organization  and  make  big 
money.  We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers. Widener  of  Kansas  City  makes  Jl  50.00 
weekly.  You  can  do  as  well  or  better.  Write  today 
for  catalog,  and  discounts.  Name  your  county.  Wave- 
land  Radio  Company,  Div.  52,  1027  No.  State  St.,  Chi- 
cago.   III. 


MANUFACTURER'S    AGENT    calling    on     Radio-Elec- 
trical JobberB,  Chicago  and  vicinity,  has  opening  for  3 

to    large    jobbers.        Edelstein,    1804    McCormick    Bid., 
Chicago.  K 


AGENTS— WRITE  FOR  FREE  SAMPLES.  Sell  Madison 
"Better-Made"  Shirts  for  large  manufacturer  direct  to 
wearer.  No  capital  or  experience  required.  Many 
earn  $100  weekly  and  bonus.  MADISON  MFGRS..  501 
Broadway,  New  York. 


90c  an  hour  to  adv 

rtiai?  and  distribute  samples  to 

con- 

turner,       Write     qu 

ick     for     territory     and     partic 

-ilars. 

American  Product 

Co.,  2130  American  Building, 

Cin- 

cinnati,  Ohio. 

Mi 


nted     for     thii 


territory  to  sell  wonderful 
value  men's,  women's.  Children's  shoes  direct,  sav- 
ing consumer  over  40'*c.  Experience  unnecessary. 
Samples  supplied.  Big  weekly  permanent  income. 
Write  today  Tanners  Mfg.  Co.,  1334C.  St.,  Boston,  Mass. 


"B"    BATTERIES 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parts  and  plans— complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake,  Chicago. 


BATTERIES  FOR  SALE— Four  24-volt  "Main"  Storag 
"B"  Batteries,  never  used,  shipped  and  ready  to  wir 
for  f38.00.  First  order  gets  the  batteries.  Addres 
Box  B,  Radio  Age,  500  N.  Dearborn  St.,  Chicago,  HI. 


BUSINESS   OPPORTUNITY 


MR.  MANUFACTURER:  Would  you  be  interested  in 
a  national  advertising  campaign  to  reach  more  than 
two  million  prospective  buyers  of  quality  radio  products 
— each  week?  Do  you  want  to  establish  agencies  in 
new  territory  and  create  national  interest  in  your 
product — at  a  very  conservative  cost?  It  can  be  done. 
Let  ua  explain  our  system  without  obligation  to  you. 
Drop  a  card  to  Radiograph  Laboratories,  1234  Roi 
Ave.,  Chicago,  111.,  Box  6. 


CRYSTALS 


TESTED  GALENA  CRYSTALS,  50c  pou 
kett,  Geologist,  Joplin,  Mo. 


id  bulk.     Bu 


HELP  WANTED 


RADIO  SALESMEN  and  SET  BUILDERS— We  need 
you  and  you  need  us.  If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  111. 


MEN  wanting  forest  ranger,  railway  clerk  a 
government  positions,  write  for  free  parti, 
exams.      Mokane,    Dept.    B-33,   Denver,   Colo. 


Classified  ad.  copy  for  the  August 
RADIO  AGE  must  be  sent  in  by 
July  1,  1925. 


INVENTIONS 


Ma 


ufac- 


NEW    IDEAS  WANTED— Well   known    Radi 

turer  whose  products  are  nationally  advertised  and  sold 

everywhere  wants  new   Radio  device  to  sell.      Will  pay 

outright  or  royalty  for  idea  or  invention  which  is  really 

new  and  saleable.      Address:      Mr.   R.  F.  D 

1101,  116  West  32nd  St.,  New  York.  N.  Y. 


MAGAZINES 


DREAMS.  A 
are  interested  i 
health,  love  an 
out  this  maga: 
fascil 


nagazine    for    all    who    dream.       If    you 
i  the  subjects  of  science,  sex,  psychology, 
e  and  romance,  you  cannot  afford  to  be  with- 
lagazine.     Three  dollars  will  bring  this  most 
g    monthly    publication    to    your    home    for 
one  year.     M.  B.  Smith  Publishing  Co.,  508  N.  Dearborn 
St.,  Chicago,  111. 

MANUFACTURING  FACILITIES 

AN  OLD  AND  WELL  ESTABLISHED  MANUFACTUR- 
ING COMPANY  IN  THE  MIDDLE  WEST  WITH  LARGE 
WELL  EQUIPPED  PLANTS  AND  UNUSUAL  FINAN- 
CIAL RESOURCES.  DESIRING  TO  ENTER  THE  RADIO 
FIELD  WILL  CONSIDER  THE  MANUFACTURE  AND 
SALE  OF  RADIO  SETS  OR  DEVICES  OF  OUTSTAND- 
ING AND  UNUSUAL  MERIT  ON  A  ROYALTY  BASIS. 
ADDRESS  BOX  1A,   RADIO  AGE. 


FOR  SALE: 
ment  for  PI 
tion  of  the  a 


PATENTS 

U.  S.  and  Canadian  Patent  on  an  Attarh- 
onographs:  is  the  most  beautiful  inven- 
re.     Address  Chas.  F.  Smith,  Huff,  N.  Dak. 


PERSONAL 


LONELY  HEARTS:  Exchange  letters;  make  interesting 
new  friends  in  our  jolly  club.  Eva  Moore,  Box  908, 
Jacksonville,  Florida.    Enclose  stamp. 


You    Radio   Bugs!      Join 
Entirely    new.       Broade: 
ige    ideas.    'Membership 
Dime  stan       " 


e,  Box  662,  Cleveland,  Ohio 


orrespondence 
acquaintance, 
LADY  BUGS 
nd  Radio  Novelty 


PRINTING 


:ionery.     Booklets,     Catalogs, 
mercial  Press,  Batavia,  Ohio 


RADIO 


A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  111. 

Standard  soderless  radio  Jacks.  Binding  pott  attach- 
ments. Double  circuit.  One  dollar  bill.  Postpaid. 
Clinton  Seward,  Jr.,  New  Paltz,   Now  York,   N.   Y. 

Three  Cosmopolitan  Phusiformers,  each  $5.50,  book  of 
instructions  included.      F.   A.    Mall,   Triopli,    Iowa. 

FOR  SALE— 3  Pfanstiehl  tuning  units,  3  Cardwell  Con- 
densers, 1  Bradleyomater,  2  Bradleystats.  All  goods 
New.     Earl  Price,  Lodi,  Wis. 

15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.  Every  item  guaranteed.  Tell  us  your  needs. 
IMPERIAL  RADIO  COMPANY,  Delaware,  Ohio. 

RADIO  SETS.  Our  prices  save  you  money.  Lists  free. 
The  Radio  Shoppe,  Box  645.  East  Liverpool,  Ohio. 

AT  LAST  The  Radco  Static  Eliminator.  Eliminates 
50  to  90%  Static.  Many  satisfied  users.  Write  for 
particulars.  Radio  Specialties  Company,  Sioux  Falls. 
South    Dakota. 


Maybe  an 

Opportunity 

awaits  You  in  the 

Radio  Age  Classified 

Section 


RADIO  CIRCUITS 


SPECIAL  FOR  JULY 
rtz  Radio  Booklet,  by  Frank  D.  Peame,  fullv 
,  and  RADIO  AGE,  for  J2.50.      Price  of  Book- 
Send  check,  currency  or  money  order 
orn  Street,  Chicago. 


to  RADIO  AGE,  500  N 


RADIO  DEALERS 


DEALERS— Write  for  our  illustrated  catalog  of  relia 
Radio  Merchandise.  Rossiter-Manning  Corporate 
Dept.  D,  1830  Wilson  Ave.,  Chicago,  111.         v-orpor"t" 


RADIO  SUPPLIES 


Ten  per  cent  discount  on  all  standard  radio  parts, 
from  condensers  to  transformers  to  tubes,  etc.  Send 
for  our  latest  price  list,  with  special  bargains  on  Static- 
eliminators,  portable  loud  speakers,  Radiotrons,  Ger- 
man silver  wire,  etc.  RADIOGRAPH  LABORATORIES. 
1234  Rosemont  Ave.,  Dept.  4.  Chicago,  III. 


STAMPS  AND  COINS 


158    Genuine    Foreign    Sts 
Venezuela,    Salvador    and 
China,    etc.,    only    Sc.       Fil 
60    per    cent.      Agents    Wa 


mps.  Mexico  War  Issues- 
India  Service.  Guatemala, 
lest  approval  sheets,  50  to 
ted.       Big    72-p.    Lists    Free. 


VOCATIONS 


Make    Big     Money.       Safe   and    Lock    Expert.       Wayne 
Strong,  3800  Lan  Franco  St.,  Los  Angeles,  Calif. 


WANTED 


WANTED— To 
August,    Septen 


Hellbrook.  Ari 


omplete  my  set  RADIO  ACE  need 
ler,  October,  November,  1923,  issues, 
id.     Advise  price.      Lloyd  C.  Henning, 


WIRELESS 

WANT  TO  MEMORIZE  THE  WIRELESS  CODE?  The 
Coryden  Snyder  Code  Method.  Patented,  is  quickest. 
Send  50c  coin,  stamps  or  M.  O.  to  C.  G.  Snyder.  1423 
Elmdaie  Ave..  Chicago.  III. 


WRITERS 


NEW  WRITERS  WANTED— Article*,  stories,  poems* 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No.  bunk.)  NOT  A  CORRE- 
SPONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
azines. Send  self  addressed  envelope  for  list  of  100 
subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Los 
Angeles,  Calif. 


WRITERS— Cash 
writing  for  Radio 
merits.  Write  u[ 
hook-up,  your  " 


n  on  your  knowledge  of  radio  by 
Magazines  and  Newspaper  Supple- 
your  radio  experiences,  your  new 
'ledge  of  broadcasting  stations  and 


artists.  Experienced  authors  will  correct  and  improve 
your  manuscripts— make  them  typically  professional 
work.  FREE  Criticism  and  Advisory  Service  until  your 
manuscript  is  soldi  ALL  Magazines  and  Papers  de- 
manding fiction  and  articles  dealing  with  radio.  Here 
is  YOUR  OPPORTUNITY  to  profit!  Send  for  FREE 
booklet,  "How  You  Can  Sell  Your  Manuscripts." 
Willis  Arnold  and  Associatea,  210  East  Ohio  St.. 
Chicago.  III. 


•  Plays.     Circulars  free. 


Have  you  ordered  your 
August  Radio  Age? 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  July,  1925 


The  Magazine  of  the  Hour 


71 


THE    RADIO    AGE 
BUYERS'    SERVICE 

What  do  you  want  to  purchase  in  the  radio  line?  Let  the  staff  of  RADIO  AGE  save  you 
time  and  money  by  sending  in  the  coupon  below.  Enter  the  number  of  the  article  you 
would  like  to  know  more  about  in  the  spaces  provided  in  the  coupon. 


1  "A"  Batteries 

2  Aerial  protectors 

3  Aerial  insulators 

4  Aerials 

5  Aerials,  loop 

6  Amplifiers 

7  Amplifying  units 

8  Ammeters 

9  "B"  batteries 

10  Batteries    (state  voltage) 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery  substitutes 

17  Bezels 

18  Binding  posts 

19  Binding  posts,  Insulated 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatstono 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisers 

33  Coils 

34  Coils,  choke 

35  CoiJs,  coupling 

36  Coils,  filter 

37  Coils,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance 

40  Coils,  Reinartx 

41  Coils,  stabilizer 

42  Coils,  tuning 

43  Condenser  parts 

44  Condenser  plates 

45  Condensers,  antenna  coup- 
ling 

46  Condensers,  by-pass 

47  Condensers,  coupling 

48  Condensers,  filter 

49  Condensers,  fixed  (paper, 
grid,  or  phone) 

50  Condensers,  variable  grid 

51  Condensers,  variable  mica 

52  Condensers,  vernier 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  sets 

57  Couplers,  loose 

58  Couplers,  molded 

59  Couplers,  vario 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 

71  Dial,  adjusters 

72  Dials,  composition 

73  Dials,  hard  rubber 

74  Dials,  rheostat 

75  Dials,  metal 

76  Dials,  vernier 

77  Dials  with  knobs 

78  Dies 

79  Drills,  electric 

80  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

83  Enamels,  battery 

84  Enamels,  metal 
65  End  stops 

86  Eyelets 

87  Experimental  work 

88  Fibre  sheet,  vulcanized 

89  Filter  reactors 

90  Fixtures 

91  Fuse  cut  outs 

92  Fuses,  tube 

93  Generators, high  frequency 

94  Grid  choppers,  rotary 


95  Grid  leak  holders 

96  Grid,  transmitting  leaks 

97  Grid  leaks,  tube 

98  Grid  leaks,  variable 

99  Grinders,  electric 

100  Ground  clamps 

101  Ground  rods 

102  Handles,  switch 

103  Head  bands 

104  Head  phones 

105  Head  sets 

106  Honeycomb  coil  adapters 

107  Hook  ups 

108  Horns,  composition 

109  Homs,  fibre 

110  Homs,  mache 

111  Horns,  metal 

112  Horns,  wooden 

113  Hydrometers 

114  Indicators,  polarity 

115  Inductances,  C.  W. 

116  Insulation,  molded 

117  Insulation  material 

118  Insulators,  aerial 

119  Insulators,  composition 

120  Insulators,  fibre 

121  Insulators,  high  voltage 

122  Insulators,  cloth 

123  Insulators,  glass 

124  Insulators,  hard  rubber 

125  Insulators,  porcelain 

126  Irons,  soldering 

127  Jacks 

128  Filament  control 

129  Jars,  battery 

130  Keys,  transmitting 

131  Knobs 

132  Knock-down  panel  units 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arresters 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  units 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instruments 

142  Megohmeters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeters 

148  Minerals 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,       condenser 
leak 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,  honeycomb 
coil 

256  Mountings,      inductance 

157  Name  plates 

158  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeters 

161  Oscillators 

162  Panel  cutting  and  drilling 

163  Panels,     drilled     and     un- 
d  rilled 

164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  soldering 
368  Patent  attorneys 

169  Phone  connectors,  multi- 
ple 

170  Phonograph  adapters 

171  Plates,  condenser 

172  Plugs,  coil 

173  Plugs,  telephone 

174  Pointers,  dial  and  knob 

175  Poles,  aerial 

176  Potentiometers 

177  Punching  machines 

178  Reinartz  set  parts 

179  Regenerative  set  parts 

180  Receiver  caps 

181  Rectifiers,  battery 

182  Resistance  leaks 

183  Resistance  units 

184  Rheostat  bases 

185  Rheostat  strips 


186  Rheostats,  automatic 

187  Rheostats,  battery 

188  Rheostats,  dial 

189  Rheostats,  filament 

190  Rheostats,     potentiometer 

191  Rheostats,  power 

192  Rheostats,  vernier 

193  Rods,  ground 

194  Rotors 

195  Scrapers,  wire 

196  Screwdrivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving — cabinet 

200  Sets,  receiving — crystal 

201  Sets,     receiving— knock- 


202  Sets,     receiving  —  Neutro- 

203]Sets,  receiving — portable 

204  Sets,   receiving — radio   fre- 
quency 

205  Sets,     receiving — reflex 

206  Sets,    receiving — regenera- 
tive 

207  Sets,    receiving — Reinartz 

208  Sets,  receiving — sectional 

209  Sets,  receiving — shortwave 

210  Sets,     receiving — super-re- 
generative 

211  Sets,  transmitting 

212  Slate 

213  Shellac 

214  Sliders 

215  Socket  adapters 

216  Sockets. 

217  Solder 

218  Soldering  irons,  electric 

219  Soldering  paste 

220  Solder  flux 

221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 

226  Stampings 

227  Stators 

228  Stop  points 

229  Switch  arms 

230  Switch  levers 

231  Switch  points 

232  Switch  stops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switches,  ground 
,   induct ence 


237  Switch. 

238  Switches 

239  Switches 
ble  throw 

240  Tonejwheels 

241  Towers,  aerial 

242  Transformers,     aud: 


ngle  and  dou- 


frs- 


243  Transformers,  filament 

244  Transformers,  modulation 

245  Transformers,  power 

246  Transformers,  push-pull 

247  Transformers,     radio     fre- 
quency 

248  Transformers,  variable 

249  Transmitters 

250  Tubes,  vaccuum — peanut 


251   Tubes,    vac 


-two    ale- 
rt— three  ele- 


252  Tubes, 
ment 

253  Tuners 

254  Variocouplers,  hard  rubber 

255  Variocouplers,  molded 

256  Variocouplers,  wooden 

257  Variometers,  hard  rubber 

258  Variometers,  molded 

259  Variometers,  wooden 

260  Varnish,  insulating 

261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 

265  Wire,  aerial 

266  Wire,  braided  and  stranded 

267  Wire,  copper 

268  Wire,  insulated 

269  Wire,  Litz 

270  Wire,  magnet 

271  Wire,  platinum 

272  Wire,  tungsten 


RADIO  AGE  BUYERS'  SERVICE,  500  N.  Dearborn  St.,  Chicago,  111. 

Please  Bee  that  I  am  supplied  with  buying  specifications  and  prices  on  the  articles  numbered  herewith: 

I      1       I      I      I      1      I       I       I       I       I       I       1   ~l       I 

I  am  a —  [J  Scaler  ~2\   Jobber  ~]    Mfers."  Rep.  □    Manufacturer 

Firm     [If  identified  with  Radio  industry]   

My   Occupation  —— 

My    Name    — — - 

City   ,    State   


w 


ITH  better  and  more 
powerful  broadcasting — 

and  with  a  sensitive,  respon- 
sive Telomonic  III  receiver — 

the  fascination  of  radio  con- 
tinues this  year,  regardless 
of  the  calendar. 

Write  to  Danziger-Jones, 
Inc.,  Dept.  C,  25  Waverly 
Place,  New  York,  for  book- 
let, "The  Kit  of  a  Thou- 
sand Possibilities." 


* 


TELOS 
RADIO 


The  Famous  Truly  Portable 

Telmaco  P-l  Receiver 

Four  Tuba  Do  the  Work  of  Seven 

The  peer  of  portables  in  size,  weight,  ease  of  tuning, 
selectivity,  distance,  volume,  workmanship  and  price. 
Aerial,  lond  speaker  and  batteries  self  contained. 
Complete  with  tubes  and  batteries,  $1?C00 
$143.60.    Receiver  only      ....     '*»■■«»■ 

P-l  Kit  Saves  Yon  Money  ! 
Onr  offer  of  the  Telmaco  P-l  Receiver  in  kit  form  has 
met  with  enthusiastic  reception.   ThiB  contains  all 
parts,  as  built  by  us,  including  case,  drilled  and  en- 
graved panel,  and  illustrated  instractions.  $0fl  00 

Complete  kit *<«»■ 

Ask  yourdealeror  write  us.  Descriptive  folder  free. 

Ifadio  ^Division: 

Telephone  Maintenance  Co. 

JO  So.  Weill  St.    Dept.  C  Chicago,  III. 


Syality  'Rjldio  Sxcluthtly    "?j>    Sitablished  1918 


CORRECTION 

Our  new  address  is  116-118  So.  Wells 
Street,  Chicago.  Dealers  will  please 
note  this  change  when  writing  for  a 
copy  of  our  "Salespeaker." 
11  ^HUDSON-ROSS— 116  S.  Wells  St. 
Chicago 


Write  for  64  page.  Handy  "Book 

clplea  of  Radio  by  eminent  radio  authority.  Contain; 

Dietzen,  Inc,  Dept.  A5    71  Cortlandt  St,  N.Y.  C. 


The  August  number  will  be  known  as 
"A  ROUND-UP  OF  RADIO,"  and, 
among  other  features,  will  contain  a 
62-page  blueprint  section. 


*     Tested  and  Approved  by  RADIO  AGE     * 


72  RADIO  AGE  for  July,  1925 

Going  Horatio  Alger 
One  Better 

(Continued  from  page  62) 
tion  finally  obtained  in  the  tube  labora- 
tories of  the  Westinghouse  Lamp  Com- 
pany. This  was  before  the  public  ever 
saw  even  the  old  UV200  and  UV201  tubes 
■ — when  199's  were  but  a  dream,  and  fila- 
ment currents  of  one  to  two  amperes 
were  tolerated  for  receiving  tubes. 

From  this  Mr.  Silver  graduated  to  a 
large  wholsesale  house  where  his  alert 
mind  quickly  grasped  the  fundamentals 
of  what  was  at  that  time  the  radio  busi- 
ness of  the  booming  early  twenties.  Then 
another  change,  this  time  to  a  concern 
which  then  consisted  of  but  the  chief  and 
himself,  but  which  soon  grew  to  deserve 
the  title  of  "New  York's  formost  radio 
shop,"  where  he  served  as  assistant  to  a 
prominent  engineer,  and  contributed 
toward  the  design  of  what  proved  to  be 
the  first  popular  super-heterodyne  re- 
ceiver over  offered  for  broadcast  recep- 
tion. Next,  a  trip  to  Paris,  and  medita- 
tion coupled  with  the  salt  sea  air  fired 
his  never  latent  ambition. 

"A  New  Era" 

THUS,  in  the  early  summer  of  1924, 
Chicago  saw  the  retail  store  of  silver- 
Marshall,  Inc.,  with  the  erstwhile  vigi- 
lante as  its  head.  Events  followed  each 
other  with  a  rapidity  characteristic  of  the 
radio  industry,  and  by  fall  the  young 
concern  marketed  a  line  of  products 
designed  by  Mr.  Silver  which  met  with 
instant  favor.  The  old  story  was  re- 
peated— production  could  not  catch  up 
with  demand,  and  winter  saw  Silver  and 
his  partner  working  shoulder  to  shoulder 
with  the  ever  increasing  force  of  the  new 
growing  concern.  By  spring  the  partners 
saw  the  rewards  of  their  labors  in  the 
ever-extending  businessthey  hadbuiltup. 

Mr.  Silver  is  probably  best  known  to 
the  radio  public  as  the  designer  of  many 
pieces  of  radio  equipment  and  a  number 
of  receiving  circuits  of  exceptional  merit, 
several  of  which  have  been  described  in 
this  publication.  In  addition  to  his  com- 
bination of  business  and  engineering 
ability,  his  capacity  for  describing  radio 
apparatus  involving  complex  circuits  in 
a  manner  so  simple  that  the  average  lay- 
man can  easily  comprehend,  is  one  seldom 
met  with.  His  articles  have  appeared  in 
practically  every  important  radio  publi- 
cation and  newspaper  in  this  country.  .  •■ 

Desiring  to  see  the  genus  homo  in  his 
lair,  we  called  upon  Mr.  Silver  one  day. 
We  were  ushered  into  the  presence  of  a 
mere  stripling  seated  at  an  unimposing 
desk,  who,  when  he  arose,  proved  to  be 
over  six  feet.  In  the  course  of  our  getting 
several  words  in  edgewise,  telegrams  flew 
out,  apparently  important  matters  were 
settled,  and  ideas  evolved  and  rushed  to 
the  laboratory  for  immediate  experiment. 

From  a  shelf  he  selected  one  of  a 
number  of  receivers,  handed  it  to  an 
assistant,  and  in  an  instant  a  volume  of 
sound  poured  out  of  the  loud  speaker  that 
was  amazing,  yet  with  perfect  quality. 

"What  is  it?"  we  asked.  After  a 
moment  the  answer  came,  briefly:  "Just 
a  six-tube  super-heterodyne.  I  call  it 
the  'Super-Autodyne,'  because  it  uses  an 
autodyne  frequency  changer." 

"Autodyne  frequency  changers"  not 
being  in  our  vocabulary,  we  left  after  a 
few  minutes  conversation,  impressed 
primarily  with  the  sudden  transition  of 
the  man  from  the  capacity  of  executive 
to  engineer  and  back  again,  and  the 
sincerity,  certainty  and  energy  that 
seemed  to  pour  forth  with  every  word  he 
uttered,  either  as  president  or  engineer. 


The  Magazine  of  the  Hour 


With  the  Manufacturers 


(Continued  from  page  69) 


Loop  Set  Preferable  To 
Antenna,  Says  Priess 

A  RADIO  statistican  recently  con- 
ducted a  research  among  radio  mer- 
chants and  learned  that  approximately 
53%  of  persons  who  enter  stores  to  buy 
radio  receivers  indicate  a  preference  for 
loop  sets. 

William  H.  Priess,  a  well  known  engi- 
neer and  president  of  the  Priess  Radio 
Corporation,  whose  work  for  a  number 
of  years  has.  been  exclusively  identified 
with  loop  reception,  is  naturally  one  of 
its  strongest  proponents.  The  percentage 
of  favor  toward  the  loop  which  the  statis- 
tician's research  showed  did  not  surprise 
him. 

"A  loop  set  has  a  number  of  advant- 
ages," he  said.  "The  set  can  be  installed 
quickly  and  moved  to  various  locations 
without  entailing  the  services  of  a  steeple- 
jack. It  is  the  ideal  set  to  take  in  the 
car  on  a  day's  outing  or  to  the  country 
on  a  week-end.  It  can  be  installed  in 
places  where  the  connection  of  antennae 
is  forbidden  or  impossible. 

"In  addition  to  its  inherent  mobility, 
the  loop  receiver  has  the  remarkable 
property  of  directional  reception  and 
freedom  from  certain  types  of  'static' 
disturbance.  Two  interfering  signals 
of  approximately  the  same  strength 
and  wavelength  but  coming  from  differ-^ 
ent  directions  cannot  be  separated  by 
the  ordinary  antenna  set.  With  the 
loop  receiver,  however,  this  separation 
can  be  made  complete  by  turning  the 
loop  so  that  one  of  the  stations  disappears, 
and  tuning  in  sharply  on  the  other 
station. 

"With  the  right  set  and  the  right  loop, 
satisfaction  over  the  antenna  set  is 
certain." 


Gain  in  Squeals  Very  Small, 
Says  Expert 

THE  GAIN  in  radio  reception  by  mak- 
ing the  single  circuit  receiving  set  oscil- 
late and  thus  set  up  a  discordant  howl  in 
all  the  other  receiving  sets  in  the  neigh- 
bothood,  is  so  very  small  that  it  does  not 
begin  to  compensate  for  the  added  an- 
noyance, L.  W.  Chubb,  Manager  of  the 
radio  engineer  staff,  Westinghouse  Elec- 
tric &  Manufacturing  Company,  points 
out. 

The  gain  in  reception  through  setting 
up  oscillation,  when  receiving  from  a  one 
kilowatt  station,  actually  is  a  small  frac- 
tion of  one  per  cent.  The  electrical  engi- 
neers have  determined  an  infinitesimal 
gain  in  comparison  with  the  loss  caused 
in  the  sets  of  peoples  within  a  radius 
of  two  or  three  miles  who  are  listening 
in  on  the  station. 

The  remedy  for  the  interference  caused 
by  single  circuit  radio  sets  is  not  in  pro- 
hibiting the  sale  of  these  sets,  as  advocat- 
ed in  some  quarters,  but  in  proper  use 
of  the  sets,  according  to  Mr.  Chubb. 

"The  situation  is  somewhat  analogous 
to  use  of  the  automobile,"  Mr.  Chubb 
says.  "On  occasion  the  automobile  has 
destroyed  lives  of  passengers  and  pedes- 
trians, or  otherwise  caused  great  suffering 
and  distress.  To  stop  this,  we  might 
outlaw  the  use  of  the  automobile,  but 
this  would  deprive  millions  of  people  of 
the  enjoyment  of  a  perfectly  legitimate 
pastime,  that  of  automobile  riding;  would 


Fall  Radio  Season  Now  On, 
Is  Claim 

THE  FALL  radio  season  will  com- 
mence in  June,  as  far  as  manufacturers 
of  radio  apparatus  are  concerned,  declared 
E.  Alden,  general  sales  manager  for  the 
Shaw  Insulator  Co.,  of  Irvington-Newark, 
N.  J.  Mr.  Alden  based  his  conclusions 
on  a  trade  survey  which  he  recently 
completed  from  coast  to  coast,  during 
which  he  learned  from  manufacturers 
in  every  section  that  the  demand  for 
radio  apparatus  by  the  buying  public  has 
caused  the  manufacturers  to  advance 
their  time  for  production  on  new  equip- 
ment to  the  month  of  June. 

"Strange  as  it  may  seem,"  declared 
Mr.  Alden,  "the  new  date  will  have  a 
favorable  reaction  on  the  trade  and 
will  be  the  means  of  allowing  the  manu- 
facturers to  more  properly  gauge  the 
buying  demand  throughout  the  country. 
At  the  present  time  it  is  apparent  that 
there  will  be  many  new  advancements 
made  in  set  and  parts  construction  dur- 
ing the  coming  season. 

"Notable  among  these  will  be  a  greater 
standard  of  development,  together  with 
refinements  in  general  construction  cal- 
culated to  make  radio  equipment  have  a 
greater  appeal  to  the  public,  and,  inci- 
dentally, be  the  means  of  giving  radio" 
its  rightful  place  in  the  ranks  of  the 
world's  greatest  medium  for  good  enter- 
tainment and  instruction. 

"The  entry  of  many  new  and  substan- 
tial concerns  into  radio  fields  during  the 
coming  season  will  be  one  of  the  greatest 
means  of  stabilizing  the  industry.  From 
present  indications  there  will  be  a  variety 
of  manufacturers  sound  financially,  and 
with  progressive  ideas  in  manufacturing 
in  mind,  which  will  have  a  stimulating 
tone  for  the  entire  industry  and  be  the 
means  of  placing  it  on  a  more  substantial 
basis  than  ever  before  in  its  history. 

"Parts  will  be  again  popular  factors 
during  the  coming  season,"  declared  Mr. 
Alden.  "One  of  the  leading  dealers  in 
this  country  with  whom  I  talked  during 
my  recent  trip  declared  that  the  parts 
end  of  his  business  has  been  holding  up  as 
good  during  the  early  Spring  season  as  it 
did  during  the  past  Winter.  The  trend 
during  the  coming  season  will  be  in  the 
direction  of  better  merchandise,  appeal- 
ing prices,  and  merchandise,  which  is 
calculated  to  bring  radio  to  higher  levels 
in  the  public's  buying  and  mind,  and 
consistent  with  the  great  appeal  that 
radio  has  heretofore  generally  enjoyed." 


deny  them  the  pleasure  of  their  present 
frequent  visits  with  relatives  and  friends 
in  distant  locations,  would  slow  down 
business  and  in  numerous  ways  would 
be  a  drawback.  The  ideal  remedy  for 
the  losses  caused  by  use  of  the  automobile 
lies  in  bringing  the  individual  to  so  drive 
his  machine  that  the  losses  will  be  elimi- 
nated and  the  gains  conserved. 

"So  it  is  with  the  single  circuit  radio 
receiving  set.  This  type  of  set  repre- 
sents the  most  for  the  money  that  the 
individual  can  buy.  This  simple  device 
using  one  or  two  small  tubes  and  inexpen- 
sive dry  cell  batteries,  gets  strong  signals 
from  the  broadcasting  station  and  is 
capable  of  getting  great  distances." 


I™ 

ID 


Bl IBE 


ini ihi mi  inr= ini imr=imi =ini iini in 


Is  The 

f  'ANNUAL' ' 
I     on  your 
Summer 
List? 


IF  YOU  intend  to  take  a  trip 
this  Summer,  you're  surely 
going  to  keep  in  touch  with 
Radio,  either  by  bringing  a  set 
along  or  building  one  during  the 
dull  afternoons,  from  parts  you 
can  take  with  you. 

AND  how  are  you  going  to  build 

this  set  or  study  up  on  radio  for  the  big  season  that 

is  bound  to  come  in  September? 

The  answer  is  simple.  All  you  have  to  do  is  to  invest 
ONE  DOLLAR  in  a  RADIO  AGE  ANNUAL  for  1925,  the 
world's  most  complete  and  authoritative  hookup  book, 
and  take  it  with  you,  whether  you  go  to  Eagle  River  or  the 
River  of  Doubt. 

Let  the  ANNUAL  for  1925  be  your  Radio  Companion  this 
Summer!  It  will  tell  you  whatever  you  want  to  know  in 
the  radio  line — from  troubleshooting  of  the  little  faults 
that  may  develop  far  from  home — to  the  actual  construction 
of  simple  portable  sets  or  elaborate  multi-tubers. 

GET  THE  ANNUAL  NOW— and  THEN  go  on  your  vacation! 
It  will  be  your  radio  safeguard! 


A  Big  Blueprint  Section 
for  your  Dollar! 

How  many  blueprints  could  you  buy  for  a 
dollar  if  you  started  out  to  buy  them,  one 
by  one?  Very  few,  you'll  admit.  Yet  in  the 
RADIO  AGE  ANNUAL  for  1925  you'll  find 
sixteen  full  pages  of  blueprints  in  actual 
color,  explaining  concisely  every  important 
simple  and  complicated  hookup  developed 
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Order  the  ANNUAL  NOW— for  the  limited 
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eager  radio   enthusiasts. 


$1.00  a 
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RADIO  AGE  ANNUAL 
FOR  1925 

Some  of  the  Features 


How  to  read  and  understand  hookups. 
How  to  understand  radio  phenomena. 
Building  your  first  simple  set. 
How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set 
How  to  amplify  any  kind  of  set. 
Making  a  reflex  set. 
Building  your  first  Reinartz  set. 
The  renowned  Baby  Heterodyne  No.  1. 
Adding  audio  and  radio  stages  to  the  Baby  Het. 
How  to  make  a  battery  charger. 
How  to  make  a  loud  speaker. 

RADIO    AGE    ANNUAL    BLUEPRINT    SECTION    with    such 
popular  hookups  as  the  aperiodic  variometer,   loop  sets,  feed- 


back receivers,  neutrodynes,  reflex  hookups,  Baby  Het  No.  2,  a 
Wonder  Super-Het,  and  others. 

How  to  get  rid  of  interference. 

How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super-heterodyne  for  the  super  experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

AND  MANY  OTHER  UP-TO-THE-MINUTE  HOOKUPS  AND 
ARTICLES. 


RADIO  AGE  ANNUAL  COUPON 

RADIO  AGE,  INC., 

500  North  Dearborn  St.,  Chicago,  111. 

Gentlemen:       I  want  to  be  one  of  the  first  to  get  the  RADIO  AGE  ANNUAL  FOR  192*.       Enclosed  find  $1.00 
I  am  not  satisfied  with  the  ANNUAL  I  will  return  it  within  five  days  and  you  will  refund  my  dollar. 

Name _ - — - 


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~    7-25 


I     7"25 
USEE 


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LONG    DISTANCE 

TRADE     MARK     REG, 


RADIO 


* 


While  MacMillan  Charts  the  Arctic 
Zenith  Broadcasts  to  the  World! 


Between  Alaska  and  the  North  Pole  stretches 
an  unexplored  area  one  million  square  miles  in 
extent — the  last  remaining  "blind  spot"  on  the  face 
of  the  globe. 

Over  this  vast  area  will  fly,  this  summer,  two 
great  planes  of  the  amphibian  type,  piloted  by  U.S. 
Navy  air  pilots  and  equipped  with  the  most  highly 
perfected  scientific  apparatus  obtainable  by  the 
United  States  Government.  This  entire  expe- 
dition, which  has  rightly  been  described  as  the 
greatest  expedition  of  modern  times,  is  under  the 
direction  of  Commander  Donald  B. 
MacMillan. 

The  purpose  of  the  expedition  is 
the  study  and  photographic  chart- 
ing of  this  unknown  area — and  — 
new  tests  in  radio  transmission  and 
reception  of  unparalleled  importance. 
The  section  to  be  explored  has  never 
been  heard  from  by  radio.  Commu- 
nication will  of  necessity  be  day- 
light communication,  for  in  this 
area  the  days  are  six  months  long. 

On    an    expedition   representing    so 


great  a  risk,  both  in  capital  and  human  life,  only 
the  best  in  radio  equipment  can  possibly  com- 
mand a  place.  Once  more,  therefore,  MacMillan 
chooses  ZENITH  exclusively,  both  for  his  ships 
and  for  the  two  great  planes  flying  across  un- 
charted seas  of  ice. 

Thus,  while  the  world  awaits  reports  from  this 
greatest  expedition  of  modern  times,  it  is  worth 
remembering  that  the  only  way  these  reports  can 
possibly  be  transmitted  is  by  Zenith  radio. 
Never  in  all  your  life,  it  is  safe  to  say,  will  you 
require  of  a  radio  set  such  outstand- 
ing performance  as  MacMillan  re- 
quires of  ZENITH  in  the  Arctic. 
But  can  you  imagine  greater  satisfac- 
tion than  to  know  chat  your  receiving 
set  can  deliver  such  performance, 
any  time  it's  called  upon  to  do  so? 

Call  this  evening  at  your  nearest 
ZENITH  dealer,  and  ask  him  for  a 
demonstration. 

Zenith  Radio  Corporation 

310  S.  Michigan  Ave.,  Chicago,  111. 


Costs  More— But  Does  More 


THE  complete  Zenith  line  ranges 
in  price  from  $100  to  $475. 
With  either  Zenith  3R  or  Zenith 
4R,  satisfactory  reception  over  dis- 
tances of  2,000  to  3,000  miles  is 
readily  accomplished,  using  any 
ordinary  load  speaker.  Models 
3R  and  4R  licensed  under  Arm- 
strong U.  S.  Patent  No.  1,113,149. 
They  are  NON-RADIATING. 

Zenith  4R  -  $100 
Zenith  3R  -  $175 

The  new  Super-Zenith  is  a  six-tube 
set  with  a  new,  unique,  and  really 
different  patented  circuit,  con- 
trolled exclusively  by  the  Zenith 
Radio  Corporation.  It  is  NOT 
regenerative 


SUPER-ZENITH  VII— Six  tubes-2  stages  tuned 
frequency  amplification — detector  and  3  stages  audio 
frequency  amplification.  Installed  in  a  beautifully 
finished  cabinet  of  solid  mahogany—  442s  inches  long, 
16K  inches  wide,  10%  inches  high.  Compartments  at 
either  end  for  dry  batteries.  Price  tf*fy/H/r\ 
(exclusive  of  tubes  and  batteries) 5P^5ttxJ' 


SUPER-ZENITH  VIII— Same  as  VII  except-con- 
sole  type.  Price  (exclusive  of  tubes  and  ^  OiT6^ 
batteries) _ Jp^OU 


SUPER-ZENITH  IX— Console  model  with  addi- 
tional compartments  containing  built-in  Zenith  loud 
speaker  and  generous  storage  battery  space. 
Price  (exclusive  of  tubes  and  batter-    fl»pgg 

ies) !pa5o 


reproduce  both  high  and  low  pitch  tones  otherwise 
impossible  with  single-unit  speakers.  tiSy^  *7CS 
Price  (exclusive  of  tubes  and  batteries)    ^p^x"  4  «3 

All  Prices  F.  O.  B.  Factory 


|  Zenith  Radio  Corporation 

Dept.  C7 
i  310  S.  Michigan  Avenue,  Chicago,  Illinois 

I  Gentlemen: 

s       Please  send  me  illustrated  literature  about 

I  Zenith  Radio. 


SUPER-ZENITH  X— Contains  built-in,  patented, 
Super-Zenith  Duo-Loud  Speakers  (harmonically 
synchronized  twin  speakers  and  horns),  designed  to 


.  Name 

I  Address. 


I 


*     Tested  and  Approved  by  RADIO  AGE     * 


°flfJM 


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Radio  Age's 
Broadcast 
Entertainers 
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\  Contest 


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1925 


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Is  The 

"  ANNUAL1 ' 

on  your 

Summer 

List? 


1 


IF  YOU  intend  to  take  a  trip 
this  Summer,  you're  surely 
going  to  keep  in  touch  with 
Radio,  either  by  bringing  a  set 
along  or  building  one  during  the 
dull  efternoons,  from  parts  you 
can  take  witli  you. 

AND  how  are  you  going  to  build 

this  set  or  study  up  on  radio  for  the  big  season  that 

is  bound  to  come  in  September? 

The  answer  is  simple.  All  you  have  to  do  is  to  invest 
ONE  DOLLAR  in  a  RADIO  AGE  ANNUAL  for  1925,  the 
world's  most  complete  and  authoritative  hookup  book, 
and  take  it  with  you,  whether  you  go  to  Eagle  River  or  the 
River  of  Doubt. 

Let  the  ANNUAL  for  1925  be  your  Radio  Companion  this 
Summer!  It  will  tell  you  whatever  you  want  to  know  in 
the  radio  line — from  troubleshooting  of  the  little  faults 
that  may  develop  far  from  home — to  the  actual  construction 
of  simple  portable  sets  or  elaborate  multi-tubers. 

GET  THE  ANNUAL  NOW— and  THEN  go  on  your  vacationl 
It  will  be  your  radio  safeguard! 


A  Big  Bluepnnt  Section 
for  your  Dollar! 

How  many  blueprints  could  you  buy  for  a 
dollar  if  you  started  out  to  buy  them,  one 
by  one?  Very  few,  you'll  admit.  Yet  in  the 
RADIO  AGE  ANNUAL  for  1925  you'll  find 
sixteen  full  pages  of  blueprints  in  actual 
color,  explaining  concisely  every  important 
simple  and  complicated  hookup  developed 
during  the  past  year!  The  32-page  blueprint 
section  of  the  ANNUAL  is  worth  many 
times  the  purchase  price  of  the  book  alone. 
Order  the  ANNUAL  NOW— for  the  limited 
first  edition  is  rapidly  being  bought  up  by 
eager  radio  enthusiasts. 


$1.00  a 
Copy 


RADIO  AGE  ANNUAL 
FOR  1925 

Some  of  the  Features 


$1.00  a 
Copy 


How  to  read  and  understand  hookups. 

How  to  understand  radio  phenomena. 

Building  your  first  simple  set. 

How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  aet. 

How  to  amplify  any  kind  of  set. 

Making  a  reflex  set. 

Building  your  first  Reinartz  set. 

The  renowned  Baby  Heterodyne  No.  1. 

Adding  audio  and  radio  stages  to  the  Baby  Het. 

How  to  make  a  battery  charger. 

How  to  make  a  loud  speaker. 

RADIO    AGE    ANNUAL    BLUEPRINT    SECTION    with    such 

pular  hookups  as  the  aperiodic  variometer,  loop  sets,  feed- 


back receivers,  neutrodynes,  reflei  hookups,  Baby  Het  No.  2,  a 
Wonder  Super-Het,  and  others. 

How  to  get  rid  of  interference. 

How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super- heterodyne  for  the  super  experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

AND  MANY  OTHER  UP-TO-THE-MINUTE  HOOKUPS  AND 
ARTICLES. 


RADIO  AGE  ANNUAL  COUPON 

RADIO  AGE,  INC, 

500  North  Dearborn  St.,  Chicago,  111. 

Gentlemen:      I  want  to  be  one  of  the  first  to  get  the  RADIO  AGE  ANNUAL  FOR  1925.      Enclosed  find  $1.00. 
I  am  not  satisfied  with  the  ANNUAL  I  will  return  it  within  five  days  and  you  will  refund  my  dollar. 

Name _ _ _ 


Address.. 

City 

7-25 


.State. 


j 


Unusual  Features 
IncreaseReceiving  Efficiency 


Simplifies  radio  tuning. 
Pencil  record  a  station  on 
the  dial — thereafter  simply 
turn  the  finder  to  your 
pencil  mark  to  get  that  in- 
stantly. Easy — quick  to 
mount.  Eliminates  fum- 
bling, guessing.  Furnished 
clockwise  or  anti-clockwise 
in  gold  or  silver  finish. 
Gear  ratio  20  to  1.  Silver 
$2.50.  In  gold  finish,  $3.50. 

HLTRTf-VSRHlSR 

TUNJNS       CONTROL 


IN  less  than  six  months  the  Ultra-Lowloss  Condenser  has 
proved  its  right  to  leadership  by  greatly  simplified  design, 
greater  tuning  efficiency,  and  radically  different  operating  results 
— not  only  in  the  eyes  of  scientific  and  engineering  men,  but  with 
the  buying  public  as  well. 

These  are  the  predominating  Ultra-Lowloss  features:  (1)  Single 
insulation  strip  reduces  leakage  losses  materially,  (2)  Monoblock 
mounting  with  plates  cast  into  block  reduces  series  resistance  and 
assures  positive  contact,  (3)  Minimum  of  metal  of  high  resistance 
material  in  the  field  and  frame  reduces  eddy  current  losses,  (4)  Cutlass 
Stator  Plates  produce  a  straight  line  wavelength  curve — separating 
stations  evenly  over  the  dial.  Each  degree  on  a  100  degree  scale  dial 
represents  approximately  3J<  meters  over  the  broadcast  wavelength 
range. 

This  even  separation  applies  to  both  high  and  low  wavelengths! 
Simplifies  tuning  materially! 

The  Ultra-Lowloss  Condenser  is  a  recent  development  of  R.  E.  Lacault, 
E.E.,  originator  of  the  famous  Ultradyne  Receiver. 

Design  of  Lowloss  Coils  furnished  free  with  each  Condenser  for  amateur  and 
broadcast  wavelengths  showing  which  will  function  most  efficiently  with  the 
Condenser. 

At  your  Dealer's.     Otherwise,  send  purchase  price  and  you  will  be  supplied  postpaid. 

CONDENSER 

Write  for  Descriptive  Folder. 

PHENIX  RADIO  GORP.,116-B  East  25th  St.,  N.  Y. 


* 


To  manufacturers 

who    wish   to    improve 

their  sets 

Iwill  gladly  consult  with 
any  manufacturer  regard- 
ing the  application  of  this 
condenser  to  his  circuit 
for  obtaining  best  possible 
efficiency. 


H>     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITH   WHICH  IS  COMBINED  RADIO  TOPICS 


Volume  4 


August,  1925 


Number  S 


CONTENTS 

Page 
Radio  Editorials 4 

Winner  of  the  Radio  Age  Popularity  Contest 7 

A  Plea  for  More  Smooth  Tuning  Receivers — 9 

By  Brainard  Foote 

Realizing  Economy  with  A.  C.  Tubes 11 

Deciding  on  a  Portable  Super 13 

By  Russell  H.  Hopkins 

Variations  in  DX  Reception  and  Their  Causes.. 15 

By  Ernest  Pfaff,  Assoc,  I.  R.  E. 

Some  Radio  Luminaries — and  Why 17 

A  Page  of  Interesting  Pictures 

Announcing  a  Prize  Contest  for  Readers.. .18 

Pickups  and  Hookups  by  Our  Readers 19 

Conducted  by  F.  A.  Hill 

RADIO    AGE    BLUEPRINT    SECTION 23-84 

The  First  Real  Presentation  of  All  Basic  Radio  Hookups — 
Illustrated  profusely  with  Radio  Age  Blueprints. 

With  the  Radio  Manufacturers ..85 

Standard  Radio  Receivers 87 

Corrected  List  of  Broadcasting  Stations ...98 


Radio  Age  is  published  monthly  by  RADIO  AGE,   Inc. 
Member:      Audit  Bureau  of  Circulations. 


Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500   N.  Dearborn   Street,    Chicago,    111. 
Publication   Office,    Mount    Morris,    111. 


Frederick  A.  Smith,  Editor 
Frank  D.  Pearne,  Technical  Editor 
M.  B.  Smith,  Business  Manager 


Advertising  Director 
HARRY  A.  ACKERBURG 

500  N.  Dearborn  St.,  Chicago,  III. 


Eastern  Representative 
DAVIDSON    &    HEVEY,    17  West  42nd  St.,   New  York  City 


Pacific  Coast  Representative 

V.   M.   DEPUTY  &  ASSOCIATES,    515  F.  W.   Braun  Bldg., 

Los  Angeles,  Cal. 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 
preceding  date  of  issue 

Vol.  4,  No.  8.     Issued  monthly.      Subscription  price  $2.50  a  year.     August,  1925. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris,  Illinois,  under  the 

Act  of  March  3,  1879. 


Copyright.  1SSS.  by  RADIO  AGE.  Inc. 


A  Chat  With 
the  Editor 

THIS  issue  of  our  magazine 
is  a  milepost  in  our  progress. 
This  is  the  twelfth  consecu- 
tive month  in  which  RADIO  AGE 
has  presented  a  group  of  blue- 
prints with  accompanying  con- 
structional detail.  It  is  fitting, 
therefore,  that  we  celebrate  the 
close  of  our  first  blueprint  year 
by  offering  our  readers  a  collec- 
tion of  blueprints  which  comprise 
all  the  basic  circuits  known  to 
radio.  Upon  the  circuits  described 
and  illustrated  in  this  group  ALL 
hookups  are  developed.  Other 
arrangements  may  differ  from  the 
parent  circuit  in  many  details  but 
fundamentally  all  of  them  are  only 
adaptations  of  one  of  the  basic 
designs  inside  this  cover. 

It  will  be  remembered  by  radio 
fans  that  RADIO  AGE  was  the 
first  magazine  to  present  illustra- 
tions of  radio  circuits  in  picture 
form.  That  is,  we  were  far  ahead 
of  all  other  magazines  in  producing 
drawings  in  which  the  parts  of  the 
receiver  were  indicated  in  their 
proper  location,  thus  getting,  away 
from  the  ancient  schematic  dia- 
gram. Many  old  timers  still  pre- 
fer the  wiring  diagram  but  the 
continued  success  of  RADIO  AGE 
shows  that  there  are  many  thou- 
sands of  fans  who  prefer  the  pic- 
ture diagrams.  This  magazine 
therefore  gives  both,  and  has  been 
doing  so  for  two  years. 

Other  magazines  have  fallen  into 
line,  although  tardily  and  the 
picture  diagram  is  an  essential 
these  days.  We  predicted  we 
would  have  imitators  and  we  are 
pleased  that  our  competitors  have 
justified  our  prophetic  accuracy 
and  at  the  same  time  have  flattered 
us  by  thus  plainly  showing  their 
approval  of  our  original  methods  of 
helping  those  who  built  their  own. 

Now  several  other  publications 
have  taken  a  deep  breath  and 
leaped  into  the  making  of '  blue 
prints.  After  one  year  of  offering 
an  exclusive  blueprint  feature  we 
again  are  pleased  to  have  "follow 
the  leader"  publications  admit 
they  have  been  behind  the  times 
for  twelve  months. 

After  all ,  what  makes  a ' '  big' '  mag- 
azine?   We  leave  the  answer  to  you. 

Editor  Kadib  Age. 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


EVEREADY    HOUR 
EVERY    TUESDAY    AT   S   P.   M 

(Eastern  Standard  Time) 
For  real  radio  enjoyment,  tune  in  th( 
"Eveready  Group."     Broadcast  through 
WEAF     New  York 
WJAR      Providence 
WEEI        Boston 
WFI  Philadelphia 

WGR         Buffalo 
WCAE      Pittsburgh 


* 

PREFERRED 

It  is  no  accident  that  more  Eveready  Radio 
Batteries  are  purchased  by  the  radio  public  than 
any  other  radio  battery  made. 

Such  complete  and  voluntary  endorsement- 
can  lead  to  but  one  conclusion — for  best  recep- 
tion and  longest  life,  Eveready  Radio  Batteries 
lead  the  field. 

You  can  prove  this  for  yourself  by  hooking 
Eveready  Radio  Batteries  to  your  set.  You  will 
find  that  they  deliver  a  steady,  vigorous  stream 
of  power  that  lasts  longer.  It  is  Eveready 
economy  that  has  created  such  an  overwhelming 
preference  for  Evereadys.  For  every  radio  use 
there  is  a  correct,  long-lasting  Eveready  Radio 
Battery.  There  is  an  Eveready  dealer  nearby. 
Manufactured  and  guaranteed  by 

NATIONAL  CARBON  COMPANY,  Inc. 

New  York  San  Francisco 

Canadian  National  Carbon  Co.,  Limited,  Toronto,  Ontario 

EVEREADY 

Radio  Batteries 

-they  last  longer 


ggg^a 


*     Tested  and  Approved  by  RADIO   AGE 


4  RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


RADIO  Corporation  of  America  has  quit  its  fight 
to  deprive  RADIO  AGE  of  its  name.  It  now 
appears  that  the  title  of  this  magazine  will  be  duly 
registered  in  the  United  States  Patent  Office  at  Wash- 
ington and  that  the  publishers  will  be  left  in  peaceful 
enjoyment  of  the  snappiest  and  most  expressive  name 
in  the  radio  publication  field. 

The  immediate  reason  for  this  fortunate  ending  ot 
the  controversy  is  the  decision  of  Radio  Corporation 
to  discontinue  publishing  "Wireless  Age."  The  Cor- 
poration bought  "Wireless  Age"  with  other  assets  which 
it  took  over  from  the  Marconi  Wireless  Telegraph 
Company  several  years  ago. 

When  RADIO  AGE  applied  to  the  Patent  Office 
in  July  1924  for  registration  of  its  title  the  Radio 
Corporation  interposed  formal  opposition  on  the  ground 
that  the  name  RADIO  AGE  was  causing  confusion 
in  the  public  mind  between  RADIO  AGE  and  "Wire- 
less Age."  The  publishers  of  RADIO  AGE,  having 
been  building  up  the  prestige  of  their  name  for  several 
years,  resisted  the  Radio  Corporation's  contention 
vigorously  and  the  details  of  the  controversy  have 
interested  many  thousands  of  radio  fans,  as  well  as 
editors  and  publishers  who  are  naturally  interested  in 
such    litigation. 

It  is  to  be  regretted  that  the  legal  points  involved 
could  not  have  gone  to  a  decision.  This  magazine  has 
been  sincere  in  its  conviction  that  it  was  morally  and 
legally  entitled  to  the  name  which  it  has  endeavored 
to  identify  honorably  and  helpfully  with  the  progress 
of  radio  in  the  United  States. 

We  are  informed  that  the  subscription  list  of  "Wire- 
less Age"  has  been  sold  to  another  radio  publication 
and  that  the  Corporation's  magazine  will  not  appear 
after  the  August  issue.  This  is,  perhaps,  a  develop- 
ment which  points  to  more  compactness  in  the  radio 
publication  field.  RADIO  AGE,  in  the  last  few  years, 
has  absorbed  two  other  radio  periodicals.  It  is  a  field 
of  free  competition  and  only  the  fit  will  survive.  It 
is  a  business  so  keenly  competitive  that  the  successful 
radio  publisher  must  make  a  business  of  radio  publish- 
ing and  not  attempt  to  make  it  pay  him  dividends  as  a 
sort  of  by-product  of  his  other  publishing  or  commercial 
enterprises. 

As  the  dove  of  peace  settles  down  upon  our  editorial 
desk  we  look  about  us  at  the  discarded  implements  of 
war  and  we  have  the  same  sort  of  feeling  that  swept 
over  us  a  few  minutes  after  11  a.  m.,  Nov.  11,  1918. 
We  were  a  battlefront  war  correspondent  and  while  the 
dead  were  still  being  carried  from  the  American  field 
we  walked  up  to  the  German  barbed  wire  and  across  it 
exchanged  questions  with  Fritz  as  to  what  all  the  shoot- 
in'  was  for. 

The  boys  from  the  fatherland  had  their  notions 
on  the  matter  and  we  had  ours.  But  we  agreed  on  one 
thing — the  dadblamed  rukkus  was  over  and  we  couldn't 
wait  to  cut  across  the  shell-holed  scenery  and  get  back 
to  the  pursuits  of  peace.  Peace,  be  it  said,  with  honor. 
Away  with  legal  briefs!     Bring  on  the  blueprints! 

THE  radio  man  who  has  been  mixing  his  conscience 
with  his  business  policy  is  stepping  out  on  the 
long,  straight  highway  which  leads  to  permanence  and 
prosperity.    We  have  been  watching  the  radio  trade  for 


several  years  and  have  been  making  mental  bets  that 
certain  individuals  in  the  trade  would  succeed  and  that 
certain  others,  who  bore  the  outward  appearance  of 
success,  would  fail.     Most  of  the  bets  were  cashed. 

Makers  of  sets  and  parts  either  kept  faith  with  the 
public  or  they  did  not  keep  faith.  They  were  either 
after  a  quick  dollar  or  they  were  intent  on  establishing 
a  sound  business.  They  were  either  price-cutters  or 
they  aligned  themselves  with  the  anti-gyp  forces. 
They  were  building  up  suspicion  of  radio  performance 
by  selling  inferior  stuff  or  they  were  fortifying  the  radio 
industry  by  selling  merchandise  that  would  function. 

The  radio  men  with  the  conscience  are  still  in 
the  industry  and  they  are  preparing  for  immense  pro- 
duction this  season.  Some  of  them  have  been  adver- 
tising in  RADIO  AGE  since  popular  broadcasting 
first  thrilled  the  country  and  they  are  still  advertising.. 
It  is  a  pleasure  to  see  their  names  in  the  book.  They 
prove  that  honest  manufacture  and  honest  merchan- 
dising pays. 

As  time  passes  it  is  going  to  be  increasingly  difficult 
for  the  gyp  and  the  maker  of  shoddy  radio  to  exist].. 
The  fans  are  educated.  If  just  entering  the  fascinating; 
art  they  have  friends  in  plenty  who  will  warn  themm 
away  from  the  catch-penny  purveyors.  We  want  to 
add  our  voice  to  the  general  chorus  and  warn  the  radio 
beginners  to  let  the  flashy  stuff  alone.  Buy  from  the 
manufacturer  or  the  dealer  who  has  invested  heavily  of 
money  and  effort  to  build  his  business.  He  respects  his 
business  and  will  not  jeopardize  it  by  gyping  customers. 
Deal  with  manufacturers  who  advertise  in  reputable 
radio  publications.  Wise  publishers  will  not  knowingly 
accept  advertisements  from  sources  which  do  not  give: 
value  received. 

Radio  progress  has  been  marvelous  but  it  wo  add' 
have  been  more  speedy  if  it  had  not  been  for  the- 
ghouls  who  tried  to  raid  it  before  its  structure  was; 
scracely  begun.  The  radio  industry  is  on  its  feeir  arudi 
it  is  a  giant.    The  day  of  the  gyp  is  numbered. 


Certain  editors  of  radio  publications  constantly  are 
shouting  that  their  editorial  columns  are  not  for  sale. 
Yet  we  seem  to  detect  evidences  that  some  of  them 
have  been  sadly  tempted. 


Radio  is  fortunate  in  having  one  of  its  leading" 
figures  represented  in  the  MacMillan  expedition  to  the' 
arctics.  The  presence  of  E.  F.  MacDonald,  Jr.,  presi- 
dent of  the  Zenith  and  Radio  Corporation,  as  commainidl- 
er  of  MacMillan's  second  ship,  the  "Peary"  assumes  the 
world  that  whether  this  adventurous  group  fund  the 
unexplored  continent  or  not  they  at  least  will  give  low 
wave  radio  transmission  the  most  effective  test  tl  has 
ever  enjoyed. 


We  are  receiving  numerous  letters  from  our  English 
and  Australian  readers.  They  are  eagerly  testing  and 
proving  the  blueprints.  Brazil,  Japan,  Holland, 
Germany,  France  and  South  Africa,  as  well  as  Mexico, 
Cuba  and  Porto  Rico  are  represented  on  the  growing 
subscription  list.  Verily  the  hook-up  is  the  same  in 
all  languages. 


RADIO  AGE  for  August,  1925 


The  Magazine,  of  the  Hour 


Introducing  the  Winner! 


Photo  posed  espeoially  for   RADIO    AGE. 

HE  WINS  RADIO  AGE  SHIELD 
Karl  Bonawitz,  premiere  organist  for  Radio  Station  WIP,  the  Gimbel  Brothers  radiocast 
at  Philadelphia,  Pa.,  emerged  with  first  honors  securely  won  after  the  final  count  in  the 
first  annual  RADIO  AGE  Broadcast  Entertainers'  Popularity  Contest.  Karl  maintained 
a  steady  lead  throughout  the  entire  competition,  which  started  last  July.  A  picture  of  the 
shield  to  be  presented  to  him  will  be  found  on  page  8,  this  issue,  with  the  Contest  Editor's 
comment  on  pages  7  and  8. 


I rflxe  Horning  Offe 


will  now  Jbe  f  '«^ 


you  may  escape 

but  not  the  need  ofQZAHKASERVICE 


THE  satisfaction  you  receive  from  your  radio  depends 
not  on  what  it  does  once  in  a  while— but  night  after 
night  and  month  after  month.  Whether  you  grin  or  cuss 
depends  on  the  service  behind  your  radio. 

Ozarka  radio  instruments  are 
only  sold  by  trained  factory  rep- 
resentatives, men  who  not  only 
specialize  in  radio  but  sell  and 
service  Ozarkas  only.  3,100 
of  these  men,  trained  directly 
under  Ozarka  engineers  consti- 
tute a  service  force,  unequalled 
elsewhere  in  radio  today. 


When  you  buy  a  radio  you'll 
compare  appearance,  tone,  vol- 
ume and  selectivity  by  having 
various  instruments  set  up  in 
your  own  home  but — that  isn't 
enough  —  compare  the  service 
behind  each  one. 

Any  Ozarka  factory  represent- 
ative will  set  up  an  Ozarka  in 
your  home  —  he  will  not  even 
operate  it  himself,  but  depend 
for  his  sale  on  what  you  your- 
self do.  If  you,  by  your  own 
operating,  do  not  bring  in  the 
distance,  the  volume  and  tone, 
you  expect  a  radio  to  give,  then 


do  not  buy  the  Ozarka.  If  you 
do  buy  it,  you  can  rest  assured, 
no  matter  what  happens,  a  com- 
petent service  man  is  at  your 
call  at  all  times.  No  Ozarka 
representative  can  sell  Ozarka 
Instruments  without  giving 

Ozarka  service.  You  are  entitled  to 
such  service  —  demand  it! 

The  Ozarka  Representative 
knows  every  part,  every  wire 
of  the  Ozarka.  In  fact  he  com- 
pletely assembles  his  own 
instruments.  His  training  on 
installations,  aerials,  ground 
connections,  operation  and 

service  comes  directly  under  our  own 
engineers  who  designed  and  perfected 
the  Ozarka  circuit. 

That  is  why  our  book,"Ozarka 
Instruments  No.  200,"  describ- 
ing all  models  of  Ozarka  should 

be  of  particular  interest  to  you.  This 
book  and  the  name  of  the  Ozarka  rep- 
resentative near  you,  will  be  sent 
immediately  at  your  request.  Please 
give  the  name  of  your  county. 


We  Have  Openings  for  a  Few 
More  Ozarka  Factory 
Representatives 

OZARKA  Incorporated,  is  now  entering  its  4th 
year.  From  a  beginning  with  one  engineer, 
one  stenographer,  one  salesman  —  our  present 
president,  the  Ozarka  organization  has  grown  to 
over  3100  people.  There  must  be  some  good 
reason  for  this  growth. 

Ozarka  instruments  have  made  good  —  they 
have  more  than  met  competition.  Ozarka  repre- 
sentatives have  made  good  not  only  because 
Ozarka  instruments  were  right,  but  because  they 
have  been  willing  to  learn  what  Ozarka  engi- 
neers were  willing  and  capable  to  teach  them — 
Ozarka  unusual  salesmanship  and  Ozarka  service. 
There  are  still  openings  for  the  right  men  in  this  organi- 
zation— men  who  believe  in  the  future  of  radio — men  who 
are  tired  of  working  for  some  one  else— men  who  want  a 
business  of  their  own.  Prove  yourself  by  sales  and  will- 
ingness to  learn  and  exclusive  territory  will  be  given  you. 
The  man  we  want  has  lived  in  his  community  for  some 
time.  He  has  the  respect  of  his  fellow  men  because  he  has 
never  "put  anything  over"  just  to  make  money.  He_  may 
not  have  much  money,  but  he  is  not  broke  and  is,  at 
least,  able  to  purchase  one  demonstrating  instrument. 

Check  Coupon  for  FREE  Selling  Book 

Radio  offers  a  wonderful  opportunity  to  men  who  are  will- 
ing to  start  at  the  bottom  and  build.  You  need  not  know 
salemanship,  but  will  you  learn  what  we  will  gladly 
_  teach  you?  You  may  not  know  radio, 

but  we  can  and  will  teach  you  if  you 
will  do  your  part.  With  such  knowl- 
edge and  willingness  to  work.it  doesn't 
seem  possible  that  you  cannot  make 
good.  Sign  the  coupon  below,  don't 
fail  to  give  the  name  of  your  county. 
Better  still  write  a  letter,  tell  us  about 
yourself  and  attach  the  coupon.  If 
interested  in  our  salesman's  plan  ask 
for  "Ozarka  Plan  No.  100." 


121  Austin  and  La  Salle  Streets 
Chicago,  Illinois 


Gentlemen:    Without  obligation  send  book  "Ozarka  Instru- 
ments No.  200"  and  name  of  Ozarka  representative. 


Name 

Address City- 
County State — 


//VftlRPORftTft} 

121  AuBtin  and  La  Salle  Streets 
Chicago,  Illinois 

Gentlemen :    I  am  greatly  interested  in  the  FREE  book  "The 
Ozarka  Plan"  whereby  I  can  sell  your  radio  instruments. 


Address City- 
County - State-.- 


#      Tested  and  Approved   by  RADIO   AGE      # 


RUG  14  75 

r 


(5)C1B665129 
RADIO  AGE  for  August,  1925 
m  ini inr  ini= inr 


The  Magazine  of  the  Hour  7 

ni ini mi  ini inr  irer=- 


mm 

J!fe  Magazine  ftha  Hour 


M.  B.  Smith 

Business  Manager 


A    Monthly     Publicatio 

Devoted  to  Practical 

Radio 


Frederick  A.  Smith 

Editor 


=ircii mi  mi  ini  ini  inr mr=  inr=  inr=^=inr==inr==inn==imr 


Results  of  Readers'  Vote- 

BONAWITZ  WINS  Contest! 


BY  popular  acclamation,  Karl  Bona- 
witz, organist,  has  been  chosen 
winner  of  the  RADIO  AGE 
Broadcast  Entertainers'  Popularity  Con- 
test for  1924-25.  By  virtue  of  his  victory 
he  will  be  awarded  the  winner's  shield. 

Getting  off  on  an  early  start,  the  name 
Karl  Bonawitz  appeared  in  eighth  posi- 
tion after  the  first  thirty  days  of  the  con- 
test. During  the  next  month  he  climbed 
to  third  place.  Then  with  the  contest 
only  one  quarter  of  the  way  through,  he 
suddenly  jumped  to  the  head  of  the  list 
where  he  has  been  continuously  threaten- 
ed by  Bill  Hay,  Bert  Davis  and  H.  W. 
Arlin,  but  never  at  any  time  displaced. 

K.  B.,  as  he  is  familiarly  known  to  the 
thousands  of  radio  fans,  might  justly  be 
christened  "The  Monarch  of  the  Reeds." 

One  year  ago,  in  the  July,  1924,  issue 
of  RADIO  AGE,  there  appeared  a  full 
page  announcement  of  the  RADIO  AGE 
Broadcast  Entertainers'  Popularity  Con- 
test. 

"Who  is  your  candidate  for  the  Radio 
Hall  of  Fame?"  is  the  way  it  was  pre- 
sented to  our  readers. 

Open  To  AH 

THE  candidate  could  be  any  person 
identified  with  radio,  including  an- 
nouncers, entertainers,  inventors,  manu- 
facturers, or  in  fact  any  person  in  any 
manner  connected  with  the  great  radio 
industry.  Beginning  with  that  issue, 
ballots  appeared  in  twelve  successive 
numbers  of  the  magazine,  the  last  one 
being  presented  in  RADIO  AGE  for 
June,  1925. 

During  that  period  thousands  of  radio 
fans  were  given  the  opportunity  of  nam- 
ing their  favorite,  and  as  each  ballot 
in  every  instance  registered  only  one 
vote  for  the  candidate,  it  is  believed  that 
the  winner  was  selected  strictly  on  his 
own.  merits.  RADIO  AGE  maintained 
an  attitude  of  strictest  impartiality 
throughout    the   contest. 

In  receiving  the  votes,  after  the  contest 
had  ended  on  midnight  of  June  15,  a 
number  of  interesting  facts  was  dis- 
closed. 

It  is  quite  singular  to  note  that  of  all 
the  hundreds  of  candidates,  that  the 
heaviest  vote  should  have  been  polled 
in  favor  of  an  organist.    For  with  all  due 


By   HARRY  ALDINE 

respect  to  the  strains  of  an  organ,  the 
performances  were  limited  and  pitted 
against  a  handicap  of  entertainers  who 
performed  nightly  over  the  microphone. 

Bill   Hay 

Bill  Hay,  Announcer  of  KFKX,  the 
Westinghouse  station  at  Hastings, 
Nebraska,  in  addition  to  taking  second 
place  in  the  contest,  must  be  given  credit 
in  being  named  the  greatest  announcer 
in  the  world.  For  from  among  the  great 
array  of  talent,  Bill  Hay  succeeded  in 
pulling  more  votes  than  any  other 
announcer.  He  is  the  only  candidate  who 
drew  the  greatest  number  of  monthly 
votes  on  three  different  occasions. 

Hay  is  Consistent 

TLTE,  like  Bonawitz,  took  off  to  early 
*-■*■  start  and  was  never  at  any  time  lower 
than  third  position.  Starting  at  the 
head  of  the  list,  he  gave  way  to  the 
organist  and  H.  W.  Arlin.  And  there  he 
staved  to  the  end  of  the  seventh  month, 


Bill  Hay,  genial  host  at  KFKX,  Hastings, 
Neb.,  who  was  among  the  leaders  when  the 
final  vote  was  taken  in  RADIO  AGE's 
Popularity  Contest.     He  won  second  place. 


when  the  announcer  from  Hastings 
deposed  H.  W.  Arlin  from  second  place. 
Two  months  later  Bert  Davis  came  along 
and  shoved  Hay  off  his  comfortable 
perch.  For  the  next  sixty  days  it  looked 
as  if  the  congenial  announcer  were 
through. 

Then,  suddenly,  Bill  Hay  staged  the 
most  remarkable  comeback  in  the  history 
of  the  contest.  Holding  a  poor  third, 
with  John  S.  Daggett  and  H.  W.  Arlin 
close  on  his  heels,  the  scattered  forces 
rallied  round  Hay,  and  with  a  deluge  of 
votes  pushed  him  back  to  the  seat  of 
honor  second  only  to  Karl  Bonawitz. 
Twenty-one  more  votes  would  have 
declared  him  winner,  which  is  the  closest 
the  organist  has  been  to  defeat  in  recent 
months. 

Forty-one  votes  behind  Bill  Hay 
comes  "The  Clown  of  the  Air,"  Bert 
Davis,  for  third  honors.  While  Bonawitz 
and  Hay  had  a  thirty  day  start  on  the 
eccentric  comedian  from  WQJ,  Bert  made 
an  excellent  showing  and  for  a  time  it 
appeared  that  he  would  run  away  with 
first  honors.  The  fans  whose  votes 
placed  the  eccentric  entertainer  at  this 
point  of  vantage,  will  undoubtedly 
regret  having  deserted  him  during  the 
last  few  days  when  a  comparatively  few 
ballots  would  have  put  him  over  the  top. 

By  way  of  consolation,  it  must  be 
noted  that  Bert  Davis  has  been  pro- 
claimed the  leader  in  his  particular  style 
of  entertainment,  as  no  singing  comedian 
leads  him  in  the  final  accounting.  A 
wandering  minstrel,  more  or  less,  since 
he  first  started  performing  over  the  radio, 
the  Clown  of  the  Air  is  now  started  on 
what  will  be  the  first  leg  of  a  trip  around 
the  world. 

Fourth  on  the  list,  we  find  "Uncle 
John  S.  Daggett,"  the  beloved  announcer 
of  KHJ,  Los  Angeles.  Here  again  we 
must  pause  to  recognize  an  exceptional 
achievement  in  Uncle  John's  having 
landed  a  place  so  close  to  the  top.  Locat- 
ed way  out  on  the  Pacific  Coast,  far 
from  the  center  of  population  of  the 
United  States,  added  to  the  fact  that 
the  contest  had  been  in  progress  for  sixty 
days  before  his  name  was  mentioned  in 
RADIO  AGE,  makes  his  showing  all  the 
more  remarkable.  From  among  the 
many  broadcasting  stations  in  his  section 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


of   the   country,    he    is   the   outstanding 
figure  west  of  the  Rockies. 

H.  W.  Arlin,  the  world's  pioneer 
announcer  from  Station  KDKA,  comes 
fifth.  During  the  early  stages  of  the 
contest  our  friend  from  Pittsburgh  con- 
sistently held  a  corner  on  the  position 
next  to  the  top  for  six  consecutive 
months.  It  was  during  the  early  part 
of  1925  that  his  support  gave  way  to  find 
him  eventually  a  little  lower  down  the 
scale.  His  record  is  worthy  of  commen- 
dation. 

There  then  follows  in  the  order  named 
Coon  Sanders'  Night  Hawks  and  Art 
Linick,  both  of  KYW;  Jack  Nelson  of 
WJJD,  Harry  Snodgrass,  formerly  WOS, 
and  Ford  and  Glenn  of  WLS.  A  refer- 
ence to  the  "Final  Standing"  will  show 
how  the  next  twenty  stood. 

There  follows  the  standing  of  the  can- 
didates as  it  looks  at  the  conclusion  of  the 
contest: 

FINAL  STANDING 

Karl  Bonawitz,  Organist WIP,  Philadelphia 

Bill  Hay,  Announcer KFKX,  Hastings 

Bert  Davis,  Entertainer. WQJ,  Chicago 

John  S.  Daggett,  Announcer KHJ,  Los  Angeles 

H.  W.  Arlin,  Announcer KDKA,  Pittsburgh 

Coon-Sanders'  Nighthawks  OrchestraKYW,  Chicago 

Jack  Nelson,  Announcer... WJJD,  Mooseheart 

Art  Linick,  Entertainer KYW,  Chicago 

Harry  M.  Snodgrass,  Entertainer 

WOS,  Jefferson  City 

Ford  &  Glenn,  Entertainers WLS,  Chicago 

Duncan  Sisters,  Entertainers.-. KYW,  Chicago 

Lee  Sims,  Pianist. ._ KYW,  Chicago 

Lambdin  Kay,  Announcer WSB,  Atlanta 

J.  Remington  Welsch,  Organist KYW,  Chicago 

'Fred  Smith,  Announcer WLW,  Cincinnatti 

E.  L.  Tyson,  Announcer WWJ,  Detroit 

Hired  Hand,  Announcer WBAP,  Fort  Worth 

"Sen"  Kaney,  Announcer KYW,  Chicago 

Nick  B.  Harris,  Entertainer KFI,  Los  Angeles 

Jerry  Sullivan,  Announcer-Entertainer.- 

WQJ,  Chicago 

Edward  H.  Smith,  Director-Player._ 

WGY,  Schenectady 

Charles  E.  Erbstein,  Announcer  WTAS,  Elgin 

Wendell  Hall,  Entertainer WDAF,  Kansas  City 

Howard  Milholland,  Announcer KGO,  Oakland 

Scottish  Rite  Orchestra KGO,  Oakland 

Banks  Kennedy,  Entertainer WEBH,  Chicago 

S.  Hastings,  Announcer KFI,  Los  Angeles 

Robert  Boniel,  Announcer WEBH,  Chicago 

Arion  Trio,  Instrumental KGO,  Oakland 

Gold  Dust  Twins.  Entertainers WEAF,  New  York 

And  now  a  few  additional  remarks  about 
the  winner  of  the  contest.  What  was 
there  about  the  performances  of  Karl 
Bonawitz  that  won  for  him  first  place  in 
the  hearts  of  the  great  radio  audience? 

The  following  is  a  letter  typical  of 
the  many  which  accompanied  the  votes 
received  by   Harry  Aldine. 

123  Waverly  Place, 
Trenton,  New  Jersey, 

February  4,  1925. 
RADIO  AGE, 
500  N.  Dearborn  St., 
Chicago,  Illinois. 

Att.:  Mr.  Harry  Aldine,  Contest  Editor. 
Gentlemen: 

Kindly  enter  my  vote  herewith  for  Mr. 
Karl  Bonawitz.  His  informal  manner  of 
announcing  makes  one  feel  he  is  playing 
tor  the  liseners  in  personal  benefit.  His 
happy  manner  is  certainly  medicine  to 
those  who  cannot  get  out  of  a  sick  room. 
If  this  peculiar  method  of  announcing 
and  his  clever  playing  can  in  any  way 
make    life    more    worth     while    to    un- 


"The  Clown  of  the  Air,"  Bert  Davis,  who 
made  a  big  spurt  toward  the  end  of  the  con- 
test and  missed  winning  the  coveted  shield 
by  only  a  few  votes.  Bert's  popularity 
among  Middle  Western  fans  grew  amazingly 
duringthelife  of  the  contest.  He  finished  third. 

fortunate  shut-ins,  he  surely  deserves  to 
win  your  contest. 

Very  truly  yours, 

Thomas  Prentice. 

His  Life  Story 

Karl  Bonawitz  was  born  in  Phila- 
delphia in  1894.  He  studied  organ,  piano 
and  musical  composition  in  that  city; 
also  in  London  and  in  Berlin. 

The  thousands  of  radio  fans  who  have 
heard  and  enjoyed  his  organ  recitals  were 
first  introduced  to  him  at  the  German- 
town  Theatre,  where  he  went  on  the  air 
for  his  initial  performance.  This  was 
in    May,    1923. 

He  was  at  once  accepted  by  the  delight- 
ed fans,  who  sent  an  avalanche  of  con- 
gratulatory messages  to  the  Gimbel 
Brothers  Station,  WIP,  at  Philadelphia, 
who  broadcast  the  strains  of  the  German- 
town  organ. 


A  view  of  the  shield  which  is  to  be  presented 

to  Karl  Bonawitz  on  behalf  of  the  readers  of 

RADIO   AGE.     It  measures  six    by  eight 

inches  over  all'. 


In  the  two  years  that  followed,  Karl 
Bonawitz  has  rendered  over  two  thousand 
compositions.  Thousands  of  letters  and 
telegrams  give  testimony  to  the  recep- 
tion accorded  this  popular  entertainer. 

Performing  from  one  of  the  largest 
instruments  in  the  country,  this  pioneer 
broadcasting  organist  "Could  make  the 
reeds  talk,"  and  the  simple  manner  in 
which  he  made  his  announcements 
between  numbers  made  the  listeners 
realize  that  he  was  not  "acting." 

RADIO  AGE  congratulates  Karl 
Bonawitz  on  his  success.  In  behalf  of 
the  others  who  made  such  an  excellent 
showing,  we  can  only  regret  that  there  is 
but   one   first   place. 

A  Word  from  the  Winner 

SINCE  closing  its  first  editorial 
forms,  RADIO  AGE  has  been 
fortunate  enough  to  hear  from  the 
winner — Karl  Bonawitz.  He  is  now  play- 
ing the  organ  in  the  Stanley  Theater  in 
Atlantic  City,  N.  J.,  where  the  bathing 
beauties  flock  every  year. 

However,  let's  let  Karl  tell  the  story  in 
his  own  way. 

Here's  his  letter: 
"Harry  Aldine, 
Popularity  Contest  Editor, 
RADIO  AGE: 
"Dear   Harry: 

"I  received  your  kind  letter  and  I  am 
very  much  pleased  to  hear  that  I  have 
won  the  RADIO  AGE  Radio  Favorite 
Popularity  Contest,  which  was  begun  a 
year  or  so  ago. 

"I  stopped  broadcasting  a  month  ago, 
although  I  notice  I  have  been  getting 
votes  since  then.  When  I  saw  that  there 
might  be  a  chance  of  my  winning  your 
contest,  I  made  several  announcements 
by  radio  concerning  your  excellent  maga- 
zine and  its  popularity  contest. 

"I  started  broadcasting  from  the  Ger-' 
mantown  Theater  organ  on  May  15, 
1923,  and  thereafter  I  was  on  the  air 
three  and  four  times  a  week  with  organ 
recitals  and  Sunday  night  concerts. 
I  have  letters  from  all  over  the  country 
and  telegrams  numbering  over  1,500. 
I  have  never  received  a  penny  for  broad- 
casting, and  in  two  years  of  this  work  I 
have  given  approximately  336  hours  of 
my  time. 

"But  don't  get  me  wrong.  I  did  it 
willingly  and  would  certainly  do  it  all 
over  again,  as  I  firmly  believe  radio 
work  is  the  greatest  advertising  medium 
in  the  world. 

"Now,  you  wanted  to  know  something 
of  my  new  activities.  On  July  3  I  will 
be  solo  organist  of  the  new  Stanley 
Theater  in  Atlantic  City,  N.  J.  We  may 
soon  be  on  the  air  again  through  Station 
WPG  at  Atlantic  City.  However,  you 
might  write  in  your  paper  that  my  posi- 
tion will  be  changed  from  the  German- 
town  Theater  in  Philadelphia  to  the 
Stanley  Theater  at  Atlantic  City. 
-  "I  hope  you'll  pardon  my  hurried  note, 
and  let  me  know  if  at  any  time  I  can  be  of 
service  to  you. 

"Sincerely, 

"Karl   Bonawitz." 

And  so  ends  the  contest.  Long  live 
the  king! 


RADIO  AGE /or  August,  1925 


The  Magazine  of  the  Hour 


A  Plea  for  More  Smooth-Tuning  Receivers 

Failure 
to  Balance  the 


Tuning  Conden- 
ser and  Coil 
Causes  Woe 

BY  BRAINARD  FOOTE 

SO  OFTEN  we  come  across  a  radio 
set  whose  tuning  dial  includes  the 
entire  broadcast  band  within  per- 
haps SO  degrees  on  a  100  degree  dial. 
The  short-wave  stations  like  WFKB, 
Chicago,  and  WHT,  Deerfield,  111.,  come 
in  at  30  and  we  find  KSD  around  80. 
Sometimes,  and  really  almost  as  often, 
the  short-wave  stations  aren't  heard 
at  all.  The  blank  spaces  at  either  ex- 
tremity of  the  dial  are  absolutely  useless 
and  they  only  serve  to  compress  the 
useful  tuning  scale  within  narrow  limits 
and  to  render  much  more  difficult  the 
exact  adjustment  of  the  dial. 

What's  wrong,  anyway?  Why  don't 
we  have  sets  that  tune  with  smoothness 
from  200  to  550  meters  over  a  scale  of 
zero  to  100?  The  fault  is  that  the  tuning 
condenser  and  the  coil  are  not  properly 
balanced.  Perhaps  the  coil  is  too  big 
or  the  condenser  too  big.  Does  the 
trouble  lie  possibly  in  the  design  of  the 
coil?  There's  a  little  of  each  to  be  con- 
sidered. 

In  the  first  place,  we  should  recall 
the  well-proved  statement  .that  the 
loudest  signals  are  obtained  with  a 
minimum  of  capacity  and  a  maximum 
of  inductance  in  the  circuit.  This  fact 
used  to  be  used  in  support  of  the  vari- 
ometer method  of  tuning  the  secondary 
circuit,  but  the  extra  length  of  wire 
required  by  the  variometer  and  its  added 
resistance  wasn't  considered.  To  keep 
.  inductance  high  and  capacity  low,  it  is 
evident  that  the  circuit  is  100  per  cent 
efficient  (if  there  is  any  such  thing)  at 
some  short  wavelength  at  which  the 
capacity  is  sufficient  to  make  the  circuit 
oscillatory  and  at  which  the  inductance 
is  predominant.  This  would  be  near 
the  "natural  wavelength"  of  the  coil. 

Distributed  Capacity 

rF,HE  fact  that  a  coil  has  a  natural 
-*-  wavelength  without  a  condenser 
connected  across  it  may  be  understood 
when  it  is  shown  that  a  coil  is  NOT  pure 
inductance.  It  has  a  certain  amount 
of  inherent  capacity,  which  is  caused 
by  the  side-by-side  position  of  the 
adjacent  wires.  When  the  wire  is  in- 
sulated with  enamel  or  single  silk,  and 
wound  closely,  the  turns  lie  very  near 
each  other  and  the  distributed  capacity 
is  very  high.  This  means  that  the  coil 
already  has  a.  certain  amount  of  capacity 


45   turns 


.0005  condenser 


Fig.  1 — A  simple  wavemeter  that  will  help 
in  the  process  of  fixing  the  coil  and  con- 
denser tuning  range.  The  points  for  200 
meters  and  550  meters  are  noted  on  the  wave- 
meter  scale  by  the  absorption  method  in  con- 
nection with  the  regular  receiving  set,  before 
the  "fixing"  process  is  started 


and  that  fewer  turns  of  wire  will  be 
needed  to  place  the  lowest  wavelength 
at  the  desired  point — 200  meters  for 
broadcast  reception.  The  effect  of  the 
tuning  condenser  is  thus  decreased;  that 
is,  a  larger  condenser  is  necessary  to 
cover    the    broadcast    band. 

Now  suppose  we  wind  a  coil  to  have 
very  little  distributed  capacity.  This 
may  be  done  in  various  ways,  the  simplest 
of  which  is  perhaps  to  employ  the 
"basket"  construction,  where  the  turns 
criss-cross  and  come  near  each  other  only 
at  the  crossing  points.  This  method  is- 
very  desirable  because  of  the  reduction 
of  distributed  capacity,  but  it  has  a 
serious  drawback  not  commonly  thought 
about.  The  wire  in  a  coil  must  describe 
a  certain  number  of  revolutions  at  a 
given  diameter  to  attain  a  certain  amount 
of  inductance.  If  each  revolution  is  a 
circle  of  that  diameter,  the  length  of 
wire  needed  will  be  a  minimum,  inas- 
much as  the  circle  is  the  geometrical 
shape  having  the  largest  inclosed  area 
for  its  perimeter.  The  basket  form 
involves  a  number  of  angles  and  the 
length  of  wire  per  turn  of  wire  on  the 
coil  is  quite  a  bit  greater.  Thus  the 
resistance    will    be   increased. 

Hence,  the  ideal  form  of  winding  is  one 
having  a  cylindrical  shape  where  the 
turns  are  spaced  from  each  other  suffi- 
ciently to  reduce  the  distributed  capacity, 
but  not  with  so  much  separation  that 
the  field  is  too  extensive.  A  spacing 
equal  to  the  diameter  of  one  wire  is 
correct  and  the  ideal  wire  size  is  from 
No.  18  to  No.  22.  Such  a  coil  can  easily 
be  made  by  using  a  treated  cardboard 
form  about  4  or  5  inches  in  diameter  and 
about  6  inches  long.  The  form  should 
be  heated  in  the  oven  to  drive   out   the 


moisture  and  then  paraffined  to  pre- 
vent moisture  from  penetrating.  The 
actual  number  of  turns  must  be  de- 
termined by  experiment,  according  to 
the  capacity  of  the  condenser,  and  of 
that  we  shall  speak  later  on. 

Spacing 

n^HE  simplest  method  of  spacing  is  to 
-*-  use  two  wires,  winding  them  both 
on  at  once.  After  the  coil  is  complete, 
one  wire  is  unwrapped  and  the  remaining 
turns  are  correctly  spaced  by  the  diameter 
of  one  wire.  A  useful  wire  to  use  for 
such  work  is  enamelled,  without  other 
insulation.  It  will  "sink"  into  the 
paraffined  surface  sufficiently  to  retain 
its  position  of  spacing.  Hard  rubber 
tubing  is  likely  to  shrink,  so  that  it  must 
be  used  for  space  wound  coils  only  where 
it  is  threaded  and  the  wire  wound  in  the 
grooves. 

Now  for  coordinating  the  condenser 
and  coil.  Take  the  usual  combination 
of  coil  and  23  plate  or  .0005  mfds.  vari- 
able condenser.  Its  effective  work  may 
start  at  15  or  20  on  the  dial  and  wind 
up  at  90.  On  the  lower  settings  it 
doesn't  amount  to  much.  The  trouble 
is  that  the  coil  is  built  to  produce  the 
longest  wavelength  near  the  highest 
setting  of  the  .0005  mfds.  condenser  and 
then  the  short  wave  setting  occurs 
wherever  luck  puts  it — usually  around 
20  or  so.  Now  it  is  NOT  possible  to 
design  a  space-Wound  coil  for  such  a 
condenser,  and  the  easiest  and  most 
practical  method  for  the  constructor 
to  follow  is  as  follows: 

1.  Wind  the  space- wound  coil  with 
too  many  turns,  perhaps  65  or  70.  Insert 
the  coil  in  the  set,  with  the  tuning  con- 
denser a,t  zero  and  find  the  wavelength, 


10 


RADIO  AGE  for  August,  1925 


The  Magazine  oj  the  Hour 


which  will  be  the  natural  wavelength 
of  the  coil  plus  an  increase  due  to  the 
minimum  condenser  setting  and  the  tube 
capacity.  This  wavelength  should  be 
200  meters,  and  to  be  absolutely  certain 
about  it  some  kind  of  a  wavemeter  is 
helpful. 

A  wavemeter  for  the  purpose  may 
easily  be  made  by  winding  about  45 
turns  of  wire  on  a  3  inch  piece  of  tubing 
about  3  inches  long,  using  small  wires, 
say  No.  24  single  covered.  Place  binding- 
posts  on  the  coil  and  fasten  lengths  of 
bus  bar  in  them  and  to  the  posts  of  a 
.0005  mfds.  mounted  variable  condenser 
as  in  Fig.  1.  Next,  tune  in  the  amateurs 
on  200  meters  (where  the  whistling  dots 
and  dashes  are  to  be  found.)  Or,  if  200 
meters  cannot  be  heard  on  your  regular 
set,  tune  in  the  shortest  wavelength 
station  you  get,  perhaps  WFKB  on  217 
meters,  let  the  set  oscillate  and  bring 
the  wavemeter  near  the  coil  of  the  set. 
Vary  its  condenser  and  at  a  certain  point 
it  will,  by  absorption,  stop  the  set  from 
oscillating.  This  is  the  corresponding 
point  on  the  wavemeter.  Note  the  dial 
reading  and  then  install  your  space  wound 
coil,  with  tuning  condenser  at  zero  and 
the  tickler  winding  placed  in  inductive 
relation  so  that  the  tube  is  just  oscillat- 
ing. Bring  the  wavemeter  near  and  vary 
the  condenser.  If  the  absorption  point 
is  less  than  the  wavemeter  setting  for 
217  meters  by  a  few  degrees,  say  four 
or  five,  the  natural  of  the  coil  is  O.  K. 
But  if  it  is  higher,  some  turns  must  be 
removed  until  the  lowest  wavelength 
tuned  in  is  about  200  meters.  It  is  best 
to  have  the  antenna  off  and  the  antenna 
coupling  coil  out  of  the  way  while  doing 
this. 

2.  The  shortest  wave  is  thus  put  at 
200  meters  with  the  tuning  condenser 
at  zero.  Now  increase  the  tuning  con- 
denser gradually  until  the  wavemeter 
absorption  method  shows  that  the  con- 
denser is  set  at  the  highest  wavelength, 
or  a  little  higher,  say  about  550  meters. 
This  will  undoubtedly  occur  at  about 
60  or  70  on  its  dial,  showing  that  the 
condenser  has  too  much  capacity.  Some 
of  its  plates  are  then  removed  by  bending 
them  back  and  forth  a  few  times  until 
they  either  break  off  at  the  rotor  shaft 
or  become  loosened  so  that  they  can  be 


V^ 


Fig.  2 — Comparative  tuning  curves  showing  the  advantage  gained  by  using  a  space  wound 
coil  and  a  smaller  condenser.  The  15-plate  condenser  was  made  by  removing  five  of 
the  rotor  plates  from  the  25  plate  instrument,   the  corresponding  5  fited  plates   thus    not 

being  used. 


pulled  out  (as  with  a  condenser  having 
plates  held  in  slots.)  In  a  typical  case, 
I  used  a  straight-line  wavelength  con- 
denser having  25  plates  and  .0005  mfds. 
capacity  with  a  space-wound  coil  that 
had  to  have  60  turns  for  200  meters  at 
zero  condenser  setting.  It  was  necessary 
to  pull  out  FIVE  of  the  rotor  plates 
before  the  tuning  range  was  properly 
spread  over  the  dial.     Fig.  2  shows  this. 

Ease  of  Tuning 

r  I  "'HE  steeper  curve  of  Fig.  2  shows 
-*-  the    tuning    scale    with    the   straight- 


line  wavelength  condenser  and  a  close- 
wound  coil  of  45  turns.  200  meters 
occur  at  about  25  on  the  dial  in  this 
case,  on  account  of  the  slight  change  in 
capacity  of  such  a  condenser  on  short 
wavelengths.  No  advantage  was  taken 
of  the  good  tuning  possibje  on  short 
waves  with  a  condenser  of  this  character. 
But  with  the  space  wound  coil,  even 
with  a  great  many  more  turns,  the  zero 
setting  is  brought  to  200  meters,  on 
account  of  the  greatly  reduced  dis- 
(Tiirn  to  page  92) 


xkc 


P/u/m. 


DbckJ&fL 


.0005 


3"i^.  3. 


-Weagant-Reinartz  circuit  for  the  space  wound  coil  and  parts  as  used  in  the  usual  three-circuit  tuner, 
lion  control  doesn't  interfere  with  the  setting  of  the  tuning  dial.     Try  it. 


This  method  of  regencra- 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


11 


Realizing  Radio  Economy  with 

ALTERNATING  CURRENT  Tubes 


THE  elimination 
of  batteries  from 
radio  receivers 
has  been  the  aim  of 
engineers  for  a  num- 
ber of  years.  The 
logical  place  from 
which  to  draw  the 
power  to  operate  our 
radio  receivers  is  the 
lamp  socket.  Here  is 
power  in  abundance, 
cheaper  by  far  than 
that  obtainable  from 
dry  batteries  or  stor- 
age batteries.  But 
the  power  is  not  in 
a  form  which  can  be 
used  directly  on  the 
modern  tubes. 

In  the  majority  of 
homes  110  volts  A. 
C.  is  employed  for 
lighting  purposes, 
whereas  we  require 
direct  current  to  light 
the  filaments  of  our 
tubes  and  to  supply 
them  with  plate  volt- 
age. How  to  use  the 
alternating  current 
for  the  purpose — that 
is  the  problem.  Ob- 
viously there  are  two 
alternatives  open  to 
us.  Either  we  may 
design  a  battery  sub- 
stitute which  will  op- 
erate from  the  alter- 
nating current  lines 
and  supply  power  to 
the  types  of  vacuum 
tubes  now  in  use,  or 
we  may  design  an 
entirely  different  type 
of  tube  which  is  cap- 
able of  being  oper- 
ated from  alternating 
current  directly. 

Without  going  into 
the  matter  in  any 
detail  we  may  state 
that  the  design  of  a 
battery  substitute  to 
supply  both  filament 
and  plate  ^current 
from  alternating  lines 
is  a  difficult  matter 
indeed.  The  plate 
supply  is  a  problem 
easyof  solution;  there 
are  many  successful 
eliminators   on    the 


°c 


T 


B 


Figure    1 


Fig.  1.     Here  is  the  schematic  drawing  for  a  typical  alternating  current  tube  supplied 

from  the  conventional  110  volt  house  supply.       The  filament  F.  F.  is  healed  by  the 

transformer  voltage  and  in  turn  it  passes  its  heat  to  the  cylinder  C  which  gives  off 

an  electronic  emission. 


Fig.  2. 


Here  the  A.    C.   tube   is  combined  with  a  kenetron  to  give  us  B  battery 
supply  from  A.  C.  mains  after  being  rectified  by  the  kenetron. 


B"  battery 
market.        By 
proper  balancing  it  is  possible  to  op- 
erate the  filaments  of  amplifier  tubes  from 
alternating  current  supplied  by  a  small 
step  down  transformer.     The  great  and 
heretofore  insurmountable  difficulty  has 
been  the  operation  of  the  detector  tube. 
Do  what  you  will,  if  the  filament  of  the 
tube  is  operated  from  alternating  current, 
there  will  be  a  terriffic  hum  in  the  output 
circuit. 


By  EDWIN  E.  TURNER  Jr 

These  difficulties  led  to  the  develop- 
ment of  a  tube  which  is  capable  of  being 
operated  from  alternating  current  di- 
rectly. Such  a  tube  is  shown  in  diagra- 
matic  form  in  Figure  1.  The  filament  of 
the  tube  F.  F.  is  a  tungsten  thread 
heated  to  incandescence  by  the  trans- 
former T  which  steps  the  line  voltage 
down    to   the   proper   value    of   5    volts. 


The  tube  draws  a 
filament  current  of 
two  amperes.  A  small 
nickel  cylinder  C,  1-8 
of  an  inch  in  diameter 
and  an  inch  and  a 
half  long,  surrounds 
the  filament  and  is 
heated  by  the  white 
hot  filament  F  F  to 
slightly  below  red 
heat.  The  cylinder  is 
coated  on  the  outside 
with  a  layer  of  bar- 
ium oxide.  Surround- 
ing the  cylinder  C  is 
the  regular  spiral  grid 
G  and  the  cylindri- 
cal plate  P.  The  tube 
is  shown  connected 
in  a  regular  single 
circuit  set,  the  plate 
voltage  being  sup- 
plied by  the"B"  bat- 
tery B.  When  the  cyl- 
inder C  is  heated  by 
the  filament  inside 
of  it,  it  gives  off 
electrons  and  acts  as 
the  source  of  elec- 
trons for  the  tube. 
But  since  it  is  in  no 
way  connected  with 
the  alternating  cur- 
rent lines,  no  hum 
can  appear  in  the  out- 
put circuit  of  the 
tube.  The  alternat- 
ing current  serves 
merely  as  a  heating 
source  to  raise  the 
cylinder  C  to  the  pro- 
per temperature  so 
that  electrons  will  be 
emitted.  The  rest  of 
the  circuit  functions 
in  the  reuglar  way. 
The  grid  return  and 
the  negative  side  of 
the  B  battery  are 
connected  to  the  cyl- 
inder C  because  this 
is  really  the  filament 
of  the  tube. 

A  Truly  A.  C.  Tube 

SO    FAR    so    good. 
Now  let  us  elimi- 
nate the   B     battery, 
making   this    a   truly 
A.    C.    tube.      There 
is    no  reason  why  we  cannot  use  a 
kenetron  in  place  of  the  "B"  bat- 
tery   to    supply    the    plate   of    the 
tube  with  high  potential  D.   C.     Figure 
2  shows  a  tube  of  the  type  which  we  have 
just  described,  supplied  with  plate  poten- 
tial  by   means  of  a   kenetron.    G,    P,    C 
and   F.    F.    have   the   same    meaning   as 
before.     A  second  transformer  T  2  sup- 
plies the  high  potential  A.   C.  which  is 
rectified   by   the   two   element   tube   F2, 
P2.      The    large    condenser    C2    is    con- 


12 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


nected  in  shunt  to  the  rectifier  to  smooth 
out  the  voltage  supplied  to  the  plate. 
One  fact  stands  out  from  figure  2:  namely, 
that  the  anode  of  the  kenetron  P2  and 
the  source  of  electrons  of  the  tube  C 
are  connected  together  directly.  There 
is  no  good  reason,  therefore,  why  they 
cannot  be  combined  into  one  electrode. 
Also,  there  is  no  reason  why  the  fila- 
ment F2  and  the  filament  FF  cannot  be 
combined  into  one,  since  the  function  of 
the  filament  FF  is  simply  to  heat  the 
cylinder  C.  Also,  the  high  potential 
winding  S  can  be  wound  on  the  same 
transformer  which  supplies  the  filament 
current  to  FF,  the  primary  of  this  trans- 
former serving  for  both. 

The  combined  circuit  is  shown  in 
Figure  3.  The  filament,  FF  heated  from 
A.  C,  serves  not  only  to  heat  the  equi- 
potential  cathode  C,  which  in  turn 
serves  as  the  secondary  source  of  elec- 
trons for  the  tube  proper,  but  also  acts 
as  the  cathode  of  the  kenetron  formed 
by  the  cylinder  C  and  the  filament.  The 
cylinder  C  acts  as  the  secondary  source 
of  electrons  for  the  tube  C,  Gr  P  and  at 


/WIT 


Fig.  3.      This  is  a  typical  one  tube  regener- 
ative circuit  with  the  A.  C.  tube  arranged  so 
it  also  delivers  B  battery  current  in  addition 
to  the  A  current. 

CI,  C2  and  C3  in  parallel  back  to  the 
electron  source  C.  The  winding  S  in 
the  tube  circuit  tested  had  a  voltage  of 
110  volts.  The  circuit  operated  as  a 
regenerative  detector  supplying  all  neces- 
sary    power    from    the     lighting    circuit 


Fig.  4.      The  alternating  current  tube  adapted  to  the  two  stage  amplifier   in  which  the  B 
battery  potential  is  also  produced  by  the  A.  C.  tube. 


the  same  time  acts  as  the  anode  for  the 
kenetron  FF,  C.  The  high  potential 
winding  S  is  connected  to  the  middle 
point  of  the  filament  lighting  secondary. 
By  tracing  the  circuit  carefully,  it 
will  be  seen  that  at  no  point  is  the  alter- 
nating current  line  connected  to  the 
filament  circuits  of  the  receiver,  the  B 
battery  return  being  made  through  the 
electron  stream  from  FF  to  C.  With  the 
tube  tested  by  the  author,  condensers 
CI,  C2  and  C3  were  2  M.  F.  each  and 
resistances  Rl  and  R2  were  36,000  ohms 
each.  This  combination  forms  a  filter 
which  serves  to  smooth  out  the  plate 
supply  to  the  tube.  It  will  be  noted  that 
these  condensers  in  parallel  are  in  shunt 
to  the  source  of  high  tension  supply,  the 
positive  terminal  of  which  is  the  filament 
FF  and  tne  negative  terminal  the  cylinder 
C.  The  load  across  these  condensers, 
upon  close  examination,  will  be  found 
to  be  the  plate  current  of  the  tube  C, 
G,  P  by  way  of  the  tickler  T,  through  the 
telephones    C4,    through    the   condensers 


former  serving  both  tubes.     The  values 
shown  are  the  same  as  before. 

A  Little  Experiment 

'T'HE  arrangements  shown  up  to  this 
*-  point  operate  satisfactorily  on  alter- 
nating current,  but  it  will  be  noted  that 
the  circuits  contain  transformers  and 
other  accessories  which  may  be  elimi- 
nated if  we  take  the  pains  to  analyze 
the  circuits.  Let  us  see  if  we  can  operate 
the  filament  of  the  tube  directly  from 
alternating  current  at  110  volts,  incor- 
porating all  the  advantages  which  we 
have  outlined.  Figure  5  shows  the 
circuit  when  the  tube  has  a  110  volt 
filament.  The  filament  F  operates  from 
110  volts  A.  C.  directly,  opeiating  exactly 
as  before  to  heat  the  cathode  C  and  to 
furnish  the  electron  emission  for  the 
rectification  taking  place  between  C 
and  F.  For  the  high  potential  to  operate 
the  kenetron,  C  F,  we  employ  the  voltage 
of  the  line  by  means  of  the  well  known 
Edison  effect.  Every  cycle  this  side 
of  the  line  X  becomes  positive  with 
respect  to  the  side  of  the  filament  Y. 
Hence  there  is  an  electron  flow  and 
rectification  between  Y  and  C.  The 
condenser  C  serves  to  smooth  out  the 
rectified  currents,  making  the  operation 
of  the  tube  more  smooth.  The  extreme 
simplicity  of  the  receiver  can  be  appre- 
ciated at  a  glance. 

And  as  a  last  step  in  order  to  bring 
the  circuit  to  the  highest  point  of  effi- 
ciency, let  us  make  the  change  shown 
in  Figure  6  by  making  the  connection 
to  the  plate  of  the  tube  to  the  middle 
point  of  the  filament  F,  instead  of  to 
one  side  of  the  line.  At  once  we  have 
done  two  things.  We  have  caused  the 
receiver  to  be  connected  to  the  alter- 
nating current  lines  at  a  point  which 
is  always  at  equal  potential  with  respect 
to   both   sides  of  the  line. 

This  alone  tends  toward  the  elimina- 
tion of  the  hum.  At  the  same  time  we 
have  substituted  for  the  half  wave 
rectification  furnished  by  the  Edison 
effect  a  full-wave  rectification.  Elec- 
tron flow  and  rectification  takes  place 
every  half  cycle  instead  of  every  cycle. 
The  electron  flow  takes  place  first  from 
one  end  of  the  filament  and  then  from  the 
other.  The  result  is  a  smoother  output 
to    the    receiver    and    less    hum. 


Fig.  5.     Now  we  are  using  110  volts  on  the 

filament  instead  of  a  lower  voltage.     Also  we 

are  supplying   the  plate  potential  through 

the  rectifying  properties  of  the  same  tube. 

at  60  cycles  A.  C.  without  the  least 
trace  of  hum.  Figure  4  shows  the 
hookup  of  a  two  stage  audio  amplifier 
using  these  tubes.  Each  tube  supplies 
its    own    plate    current,    a    single    trans- 


Fig.  6.  The  above  circuit  shows  us  the 
A.  C.  tube  at  its  highest  efficiency;  it  furn- 
ishes A  battery  current  for  the  electronic 
emission  and  also  furnishes  its  own  B  po- 
tential through  the  connection  between  the 
plate  of  the  tube  and  the  center  of  the  110 
volt  filament . 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour  13 


Deciding  on  a  Portable  Super-Het 


Small  Parts  and 

Efficient 

Transformers  are 

Vital  for  Real 

Portability 


BY  RUSSELL 

H. 

HOPKINS 


IT  HAS  long  been  acknowledged  that 
the  super-heterodyne  receiver  is 
the  last  word  in  radio  development. 
For  all-around,  all  year  reception,  under 
all  conditions,  and  for  general  efficiency 
of  operation,  the  "super"  cannot  be  sur- 
passed. 

For  too  long  a  period  the  super  was  the 
instrument  of  the  experimental  labora- 
tory instead  of  the  practical  receiver  of 
the  everyday  fan.  Too  long  have  supers 
been  great  consumers  of  battery  current 
and  occupiers  of  unwieldy  space.  Some 
radio  engineers  have  attempted  to  reduce 
the  battery  drain  by  introducing  com- 
plicated reflexing,  but  that  addition  did 
not  tend  to  bring  about  the  desired 
simplicity  that  was  essential  if  the  super 
was  to  become   universally  adopted. 

After  testing  about  every  known  type 
of  super-heterodyne  design,  from  six 
to  eight  tube  layouts  and  back  again, 
a  conclusion  was  arrived  at  that 
for  all-around  desirability,  as  well  as 
sensitivity,  selectivity,  weight  and  dura- 
bility, the  portable  super-heterodyne 
was  the  ideal  receiver  for  the  fan  who 
wants  all  the  latest  radio  improvements 
arranged  in  such  a  way  that  they  will 
constitute  a  truly  portable  receiver,  and 
not,  as  one  radio  pioneer  so  aptly  put 
it,  "so  portable  that  one  man — and  six 
boys — can   easily   carry   it   about." 

An  ideal  portable  super-hererodyne 
can  be  built  on  a  panel  7  inches  by  18 
inches  by  3-16  inch  and  a  subpanel  if 
desired.  If  old-timers  lift  their  eye- 
brows in  amazement  and  question  the 
possibilities  of  inter-stage  coupling  and 
excessive   crowding,    we   will   allay   their 


fears  by  assuring  them  that  inter-stage 
coupling  can  be  made  to  disappear  en- 
tirely in  well  constructed  portable  re- 
ceivers. 

Use   Small   Parts 

TN  designing  a  portable  super,  which  we 
-*-  have  taken  as  our  model  receiver  for 
this  discussion,  it  should  be  advisable  to 
use  instruments  that  have  been  purposely 
designed  to  permit  their  being  placed  in 
small  space.  Otherwise  we  are  taking 
great  liberties  in  calling  this  a  "portable" 
set.  At  the  same  time,  these  parts  must 
not  be  so  placed  that  they  interfere 
electrically  with  each  other. 

In  super-heterodynes,  as  in  any  receiv- 
ers, short  wires  insure  best  results,  so 
the  fact  that  a  super  was  once  a  complicat- 
ed affair  need  not  make  the  prospective 
builder  believe  that  connections  must  be 
elaborately  though  unnecessarily  long. 
Then,  again,  if  we  mount  our  parts 
compactly,  long  wiring  will  be  done 
away  with  and  we  will  have  attained  our 
ideal  from  .the  standpoint  of  wiring. 
If  our  portable  super  is  to  be  a  welcome 
companion  on  our  Summer  trips,  instead 
of  a  cumbersome  hindrance,  it  must  be 
easy  to  handle  or  we  will  wish  we  had 
left  it  at  home.  And  the  next  time  we  go 
away,  we  will  be  sure  to  leave  it  at  home, 
unless  we  make  it  as  small  as  is  possible 
without  hampering  mechanical  perfec- 
tion. 

In  our  quest  for  compactness,  however, 
we  should  not  be  blinded  to  the  fine 
qualities  that  every  receiver,  and  particu- 
larly the  super,  should  possess.  The 
foremost  _£of  _these     is     tonal     quality. 


The  portable  super  at  the  left 
gives  a  good  example  of  how  a 
mult  itube  set  should  be  laid  out 
for  true  portability.  Note  the 
compact  arrangement  of  bat- 
teries and  the  small  space 
consumed  by  them.  And 
can't  you  imagine  how  easy 
such  a  travelling  case  would 
be  to  carry  on  your  vacation? 


Without  it  a  receiver  may  get  the  sta- 
tions, but  it  will  not  get  music,  clarity 
or  sweetness  of  tone.  Selectivity,  sensi- 
tivity and  distance-getting  features  are 
admirable  when  combined  in  one  re- 
ceiver, but  tone  is  most  important,  for 
what  good  are  distant  stations  if  we  do 
not  enjoy  their  offerings? 

Portable  super-heterodyne  receivers 
have  been  snubbed  by  some  fans  who 
would  otherwise  be  loyal  boosters,  just 
because  the  designers,  in  their  mad 
chase  for  extreme  portability,  forgot  to 
include  pleasing  tone.  Even  after  tone 
has  been  achieved,  a  creditable  loud 
speaker  must  be  used  to  convey  that 
pure  tone  to  willing  ears,  and  not  con- 
vert it  into  a  "tinny,"  rasping  squeal. 
Several  small,  built-in  loud  speakers  are 
now  available,  so  there  should  be  no 
excuse'  for  imperfect  loud  speaker  re- 
production in  a  portable  set. 

The  Heart  of  the  Super 

HPHE  heart  of  the  portable  super,  as 
*-  well  as  of  the  more  elaborate  models, 
is  in  its  transformers,  for  they  are  the 
real  factors  to  consider  when  we  set  out 
for  results  in  amplification,  tone  quality, 
selectivity,  economy  of  current  consump- 
tion and  wavelength  range.  Accordingly, 
we  will  devote  part  of  this  discussion  to 
the  proper  choice  of  transformers  for  the 
portable  super-heterodyne. 

To  say  that  the  question  of  high  fre- 
quency air-core  transformers  versus  com- 
paratively low  frequency  iron-core  trans- 
formers in  a  super-heterodyne  is  a  much 
mooted  one  would  be  to  be  truthful  but 
not  at  all  original.     However,  the  super 


14 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


fan  will  be  interested  in  a  few  of  the  facts 
responsible  for  the  decision  to  recom- 
mend iron-core  transformers  in  port- 
able  supers. 

The  best  gain;  that  is,  voltage  amplifi- 
cation, that  could  be  obtained  with 
standard  air-core  transformers  varied 
between  8  and  16  with  an  average  of  14 
for  201A  tubes  and  somewhat  less  for 
UV199's.  The  voltage  gain  for  the  trans- 
formers used  in  a  portable  super  is  34 
per  stage  between  UV199's.  There  is  no 
argument  here  between  the  100  kilo- 
cycle amplifier  and  the  50  K.  C.  amplifier 
— though  the  average  iron-core  trans- 
formers on  the  market  give  a  14  to  IS 
voltage  gain  per  stage.  The  two  instru- 
ments for  which  the  makers  make  the 
most  extensive  claims  give  only  24  per 
stage,  whereas  another  transformer  for 
which  no  extensive  claims  are  made  gives 
30  per  stage.  These  latter  types  are  all 
iron-core  operating  from  6,000  to  10,000 
meters — the  low  frequency  of  the  last 
one  being  its  only  drawback. 

It  is  possible  to  tune  a  100  K.  C.  am- 
plifier using  air-core  transformers  very 
sharply  and  yet  not  cut  side-bands. 
It  is  possible  to  tune  a  50  K.  C.  amplifier 
sufficiently  sharply  so  as  not  to  cut 
side-bands  and  yet  eliminate  noises,  but 
it  is  very  difficult  to  do  so  with  a  30  K.  C. 
amplifier.  Under  certain  conditions 
of  perfectly  matched  air-core  transform- 
ers an  amplifier  might  be  made  so  sharp 
as  to  cut  the  side-bands  and  distort 
speech  received  considerably.  The  dan- 
ger of  this  is  greater  at  long  than  at  short 
waves,  but  since  iron-core  transformers 
are  generally  used  on  the  longer  waves, 
this  difficulty  disappears  here  and  holds 
only  for  the  short  wave  amplifiers  using 
air-core   transformers. 

Assuming  the  air-core  transformers  to 
be  all  adjusted  to  the  same  wavelength, 
the  selectivity  will  be  good.  If  one  is  off, 
amplification  will  fall  off  badly  and 
selectivity  will  be  poor,  due  to  the  very 
sharp  peaks  of  the  transformers.  These 
peaks  must  be  sharp  if  any  amplifica- 
tion at  all  is  to  be  obtained  from  this 
system.  Each  transformer  must  be 
matched  for  a  given  set,  and  the  trans- 
formers in  an  amplifier  should  be  matched 
for  individual  positions,  since  variations, 
which  to  some  extent  can  be  predeter- 
mined, occur  from  stage  to  stage. 

In  the  assembly  of  the  amplifier  the 
greatest  care  must  be  taken  to  see  that 
the  characteristics 
of  each  stage-assem- 
bly are  identical  or 
all  the  advantages 
of  a  well-matched 
set  of  air-core 
transformers  will  be 
lost.  Due  to  the 
lower  frequency  at 
which  iron-core 
transformers  are  op- 
erated, this  trouble 
is  practically  never 
encountered  and  a 
set  of  transformers 
could  be  built  for 
operation  of  50  K. 
C,  which  will  give 
practically  no  dis- 
tortion and  yet  have 
a  sharp  cut-off  either 


side  of  a  sufficiently  wide  speech-band. 
This  would  be  the  ideal  condition,  since 
amplification  would  remain  constant  even 
though  the  transformers  varied  slightly, 
due  to  manufacturing  difficulties.  These 
difficulties,  however,  are  very  much  small- 
er at  50  K.  C.  than  at  100  K.  C.  In  the 
case  of  air-core  transformers,  which  are 
non-adjustable,  the  selectivity  is  depend- 
ent upon  each  stage  speaking  at  substan- 
tially the  same  wavelength,  the  in-put 
transformer  used  with  them  being  used 
principally  for  other  purposes  than  to 
sharpen  up  the  amplifier  tuning.  This  is 
very  nice  where  each  stage  can  be  tuned 
individually  but  not  so  nice  otherwise. 

In  an  iron-core  amplifier  the  selectivity 
is  almost  entirely  determined  by  the  filter, 
which  means  that  the  selectivity  of  the 
amplifier  is  under  easy  and  accessible 
control  in  one  circuit — not  distributed 
over  several  non-adjustable  circuits. 
The  primary  complaint  of  lack  of  selec- 
tivity in  iron-core  transformers  is  due  to 
the  use  of  poor  filters,  as  up  to  the  present 
time  practically  no  really  sharp  filters 
have  been  marketed — the  writer  is  fami- 
liar with  only  two  which  are  not  make- 
shifts, improperly  designed. 

Attaining  Stability 

'T'HE  lower  the  frequency,  the  greater 
J-  the  stability  of  an  RF  amplifier — 
the  very  principle  of  the  super  being 
based  on  this  law  in  a  measure.  The 
feed-back  effects  are  less  the  lower  the 
frequency,  and  are  slight  in  a  50  K.  C. 
intermediate  amplifier  and  very  easily 
overcome.  Where  an  iron  core  is  used 
in  a  transformer,  the  field  is  limited  and 
shielding  may  be  employed  efficiently 
if  desired,  although  since  the  field  is 
limited,  it  is  generally  necessary  to  no 
greater  extent  thanjndividual  transform- 
er shields,  which  are  provided  on  prac- 
tically all  standard  makes  of  iron-core 
transformers.  An  air-core  amplifier  can- 
not be  shielded  without  increasing  its 
bulk  j,very  noticeably,  and  unshielded 
require  ,f  greater  spacing  than  an  iron- 
core  amplifier.  operating  at  even  the 
same  wave  length,  in  order  to  maintain 
stability. 

With  a  given  set  of  air-core  trans- 
formers designed  for  operation  at  140 
K.  C.  with  201A  tubes,  the  substitution  of 
UV  199's  would  throw  the  operating 
frequency  up  to  190  K.  C. 

This  means  that  the  wavelength  would 


Back  view  of  a  truly  portable  super-heterodyne,  for  Sum 
all-year  use.      Use  of  small  parts  enables  the  builder  of  a 
mount  his  transformers  under  the  tube  sockets  and  out  of  the 
serving  valuable  space. 


shift  from  2,150  to,  roughly,  1,600  meters 
for  this  particular  set  of  transformers. 
This  indicated  how  very  slightly  depend- 
able the  manufacturer's  rating  of  the 
operating  efficiency  of  air-core  transform- 
ers really  is.  At  these  low  wavelengths 
changes  like  this  are  of  considerable 
importance,  whereas  the  changes  which 
occur  in  iron-core  amplifiers  at  higher 
waves  are  very  slight,  principally  due  to 
the  comparatively  high  distributed  ca- 
pacity  of   the   windings. 

Since  a  50  K.  C.  amplifier  is  more  sta- 
ble than  a  100  K.  C.  one,  less  loss  in  the 
form  of  positive  grid  bias  need  be  intro- 
duced to  stabilize  it.  In  actual  practice 
the  former  amplifier  may  be  tuned  with 
the  grids  from  one  to  four  volts  negative 
with  respect  to  the  minus  end  of  the  fila- 
ment for  UV199's  The  average  positive 
bias  for  air-core  transformers  at  100 
K.  C.  with  UV199  tubes  is  one-half  to 
two  volts  positive.  It  is  an  axiom  that  a 
tube  is  inefficient  when  its  grid  is  operat- 
ing positive  and  where  a  strong  signal 
is  to  be  handled  distortion  is  bound  to 
result  from  a  positive  amplifier  grid. 
Besides  being  far  more  efficient  in  opera- 
tion, a  tube  with  a  negative  grid  bias 
consumes  very  much  less  current  than  a 
tube  with  a  positive  bias.  The  writer 
has  noticed  in  an  amplifier  using  air-core 
transformers  a  current  consumption, 
50  per  cent  greater  than  the  consumption 
of  an  iron  core  50  K.  C.  amplifier. 

The  potentiometer  controlling  regen- 
eration on  an  air-core  amplifier  will 
generally,  if  retarded  over  thirty  degrees 
of  its  arc,  throw  out  a  comparatively 
strong  station  entirely.  This  indicates 
that  the  nature  of  the  gain  in  the  ampli- 
fier is  mostly  regenerative,  since  for  good 
sensitivity  the  amplifier  must  always 
be  operated  just  below  the  oscillating 
point.  This  is  not  a  good  condition, 
since  regeneration  such  as  is  necessary 
for  sensitivity  will  distort  the  signal  in 
addition  to  rendering  the  control  of  the 
set  extremely  critical.  With  an  iron-core 
K.  C.  amplifier  this  is  not  the  case — the 
grids  are  run  negative  by  a  "C"  battery 
and  if  a  potentiometer  is  used  it  is  merely 
for  volume  control.  The  amplifier  need 
not  be  operated  just  under  the  oscillating 
point  to  secure  good  selectivity,  and  the 
potentiometer  may  be  retarded  over  its 
entire  scale  in  the  case  of  a  well  de- 
signed amplifier  without  throwing  a 
signal  out.  Unless  the  signal  is  weak, 
it  will  be  a  gradual 
decrease,  which 
means  that  is  more 
nearly  a  true  vol- 
ume control  than  in 
the  previous  case. 
Yet  the  50  K.  C. 
amplifier  will  give 
better  amplification 
with  a  non-critical 
adjustment  than  a 
1 00  K.  C.  operated  at 
its  limit — just  before 
the  oscillating  point. 

Few  Stages  Best 

'T'HE  fewer  stages 
-L  we  can  use  in  an 

amplifier    the    more 

efficient   each   stage 

(Turn  to  page  03) 


is  well  as 
set  like  this  to 
way,  thus  con- 


RADI(*>  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


15 


Where  to  Look  for  Faults  in  Reception 

The  Causes  of 

VARIATION  in 


DX  Results 


By  ERNEST  PFAFF 

Assoc,  I.  R.  E. 


IN  VIEW  of  the  fact  that  the  more  or 
less  experienced  radio  amateur,  as 
well  as  the  novice,  is  confronted 
with  such  a  variety  of  confusing  and  con- 
flicting information  regarding  the  range 
of  various  receiving  sets,  a  non-technical 
discussion  of  the  factors  limiting  long 
distance  reception  will  undoubtedly  be 
appreciated   by   many   enthusiasts. 

It  is  the  purpose  of  this  article  to  point 
out  the  limitations  of  radio  reception  in 
general,  since  the  varied  conditions  under 
which  an  instrument  may  be  operated 
makes  it  practically  impossible  to  esti- 
mate the  range  of  a  receiver  with  any 
degree  of  accuracy.  This  is  due  to 
forces  entirely  beyond  our  control,  such 
as  atmospheric  conditions  involving  the 
amount  of  moisture  in  the  air,  electrical 
charges  which  accumulate  upon  particles 
of  dust  and  moisture  causing  various 
forms  of  static,  man-made  electrical 
interference,  interference  between  direct 
waves  and  waves  which  have  been  re- 
flected from  the  upper  strata  of  the  earth's 


atmosphere,  which  manifests  itself  in  a 
fading  of  signal  strength  and  deflection 
of  radio  waves  by  large  metallic  masses. 
These  factors  will  be  dealt  with  in  some- 
what greater  detail  in  the  following 
paragraphs. 

Theoretically,  increasing  the  sensitivity 
of  a  radio  receiver  will  increase  its  range, 
because  the  energy  necessary  to  operate 
it  will  be  reduced.  The  value  of  signal 
strength  necessary  to  operate  any  re- 
ceiving system  is  generally  called  the 
threshold  value.  The  accompanying 
curve  will  show  the  approximate  thres- 
hold value  for  the  most  common  types  of 
receivers.  Abnormal  conditions  some- 
times cause  results  which  may  vary 
considerably,  but  these  results  are  termed 
"freaks"  and  are  not  worthy  of  lengthy 
discussion. 

The  curve  in  sketch  1  gives  an  approxi- 
mate idea  of  the  relative  sensitivity  of 
several  very  general  types  of  receiving 
equipment.  The  line  sloping  down  across 
the  chart  from  left  to  right  indicates  the 


gradual  decrease  of  signal  intensity  of  a 
transmitting  station  of  a  given  power, 
at  various  distances  from  the  source. 
It  will  be  seen  from  the  curve  that  it  will 
take  approximately  nine  units  of  energy 
to  operate  a  crystal  receiver. 

The  threshold  value  of  a  regenerative 
receiver  is  lower,  therefore,  decreasing 
the  amount  of  energy  necessary  to  oper- 
ate it  to  about  eight  units;  similarly  the 
regenerative  and  the  neutrodyne  re- 
ceivers require  even  less  energy.  Lastly 
the  super-heterodyne  requires  but  one 
unit  of  energy  to  operate  it  and  we  are 
consequently  at  the  point  where  a  further 
increase  of  sensitivity  will  be  of  no 
avail,  since  at  this  point  the  noise  be- 
comes louder  than  tne  signal.  In  other 
words,  if  we  decrease  the  threshold 
value  of  the  super-heterodyne  which  is 
shown  on  the  curve,  there  will  be  no  in- 
crease in  the  range  of  the  set  because  it  is 
already  capable  of  picking  up  any 
signal  that  is  audible  above  the  most 
favorable  winter  noise  level. 

The  summer  noise  level  is  so  high  that 
the  lightning  discharges  are  made  audi- 
ble in  the  most  unsensitive  receiver. 
It  should  be  noted  that  the  noise  appar- 
ently increases  as  the  sensitivity  of  the 
receiving  instrument  is  increased.  In 
order  to  make  the  received  signal  audi- 
ble, it  is  obvious  that  it  must  be  of  greater 
amplitude  than  the  noise  level.  The 
neutrodyne  is  capable  of  reaching  the 
summer  noise  level  and  during  the 
summer  months  would  have  a  range 
equal  to  that  of  any  set.  The  super- 
heterodyne, however,  has  the  distinct 
advantage  of  obtaining  the  maximum 
range  which  is  possible  under  the  very 
best  conditions  of  noise  level  and  inter- 
ference. (Turn  tie  page) 


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DISTANCE    FROM     TRANSMITTED 


tig. 
The 


1.      The  curve  in  the  sketch  above  gives  an  approximate  idea  of  the  relative  sensitivity  of  several  very  general  types  of  receivers, 
line  sloping  from    left   to   right   indicates  the  gradual  decrease  of  signal  intensity  of  a   transmitting  station  of  a  given  power  at 

various  distances  from  the  source. 


16 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


TN  VIEW  of  the  above  mentioned 
-*-  facts,  it  would  be  useless  to  build  a 
receiver  of  greater  sensitivity  than  the 
one  which  was  last  mentioned.  Adding 
additional  intermediate  frequency  am- 
plification or  preceding  a  good  super- 
heterodyne with  a  radio  frequency  am- 
plifier would  only  serve  to  complicate 
matters.  Future  development  in  radio 
receivers  will  probably  be  along  the  lines 
of  increasing  selectivity  so  that  one  may 
pick  out  any  station  desired  from  others 
which  may  be  operating  at  approximately 
the  same  wavelength.  There  will  also  be 
an  endeavor  to  simplify  this  type  of 
receiver  so  that  the  same  degree  of  sensi- 
tivity and  selectivity  may  be  had  with 
less  equipment  and  consequently  less 
cause  for  trouble. 

By  referring  to  the  above  mentioned 
curve,  it  may  be  of  interest  to  note  that 
the  signal  intensity  decreases  as  the  first 
power  for  distances  up  to  200  miles;  for 
distances  greater  than  this  the  signals 
will  decrease  according  to  an  exponential 
and  inverse  first  power  law.  These  laws 
are  more  nearly  accurate  when  the  trans- 
mission is  over  water  because  water  is 
better  conductor  than  the  earth. 

We  are  often  startled  when  we  are 
able  to  receive  a  station  at  some  consid- 
erable distance  with  comparative  ease, 
but  experience  difficulty  in  receiving 
a  more  powerful  station  which  is  not  so 
distant.  The  cause  of  this  dead  spot  or 
semi-dead  spot  is  usually  found  to  be 
some  absorbing  or  deflecting  medium 
between  the  transmitting  and  receiving 
station.  The  most  common  causes  of . 
these  dead  spots  are  ore  deposits,  moun- 
tain ranges,  heavily  wooded  tracts  of 
land,  or  groups  of  steel  buildings.  Any 
very  large  substance  which  is  a  conductor 
of  electricity  may  cause  this  effect. 
By  referring  to  the  chart,  it  is  evident 
that  station  "B"  which  is  2100  miles 
from  the  receiver,  is  to  be  received  with 
much  greater  ease  than  station  "A" 
which  is  only  1700  miles  from  the  receiv- 
er, because  the  line  of  signal  intensity 
has  been  caused 'to  follow  the  dotted 
line  of  the  curve  by  some  conducting 
object  which  is  responsible  for  this  atten- 
uation. 

With  the  advent  of  the  more  sentitive 
receivers,  many  other  limiting  factors 
have  been  realized.  The  most  common 
hindrance  to  good  reception  is  "lack  of 
selectivity."  It  is  evident  that  the 
number  of  stations' within  the  range  of  a 
receiving  set  is  increased  as  the  square 
of  the  sensitivity;  therefore,  selectivity 
becomes  increasingly  important  as  the 
threshold  value  is  lowered.  This  fact  is 
illustrated  graphically  in  sketch  2.  How- 
ever, this  factor  has  been  greatly  di- 
minished, if  not  entirely  overcome,  by 
the  super-heterodyne  type  of  receiver 
which  permits  a  very  marked  degree  of 
selectivity. 

The  Super  and   the  Loop 

TPHE  super-heterodyne  receiver  has 
■*-  another  advantage:  that  of  being 
highly  efficient  when  used  with  a  loop 
antenna,  whereas  most  of  the  other 
types  of  receivers  require  an  outdoor 
antenna  to  realize  any  great  degree 
of  sensitivity.      The   greatest   advantage 


Fig.  2.  It  is  evident  that  the  number  of 
stations  within  the  range  of  a  receiving  set 
is  increased  as  the  square  of  the  se.isi'.ivity,  so 
selectivity  becomes  increasingly  important 
as  the  threshold  value  is  lowered.  The 
sketch  above  illustrates  this  point. 

of  the  loop  receiver  is  not  its  portability 
or  ease  of  erection,  but  rather  in  the  direc- 
tional qualities  which  enable  one  to  en- 
tirely separate  two  stations  operating 
on  the  same  wavelength  if  they  are  lo- 
cated at  rigb"  angles  to  each  other  with 
respect  to  the  lo.ation  of  the  receiver. 

Since  there  is  no  reasonable  limit  to  the 
possible  degree  of  sensitivity  of  a  well  de- 
signed super-heterodyne,  one  would  natur- 
ally come  to  the  conclusion  that  there  is 
no  limit  to  the  range  of  a  receiving  system 
of  this  nature.  However  natural  this  sup- 
position may  be,  it  is  erroneous,  since 
the  principal  limiting  factor  of  radio 
reception  is  the  amount  of  noise  which  is 
always  prevalent  in  the  atmosphere, 
regardless  of  whether  it  is  made  by  natur- 
al sources,  power  lines  or  electrical 
devices.  The  causes  contributing  to 
this  phenomenon  of  noise  level  are 
numerous,  but  may  be  divided  into  two 
general  classes,  namely,  "man-made 
interference"  and  "atmospheric  disturb- 
ance." 

If  one  is  located  in  the  city,  the  factor 
of  man-made  interference  becomes  very 
serious.  This  disturbance  may  be  due 
to  any  arc  or  spark  such  as  would  be 
produced   by  a  faulty   connection   in   an 


Fig.  3.  This  sketch  shows  how  both  direct 
and  reflected  waves  travel  from  the  trans- 
mitter to.  the  receiver.  The  reflected  wave 
travels^  much  farther  than  the  direct  wave 
and  is\lherefore  subject  to  being  out  of  phase 
with  the  latter  wave. 


electric  light  socket,  vibrating  battery 
charger,  electric  furnace,  tree  branches 
rubbing  against  a  power  line  or  induc- 
tion from  any  motor  driven  apparatus 
such  as  a  washing  machine  or  electric 
dish  washer,  etc.  Violet  ray  machines 
and  "X"-ray  devices  also  are  a  common 
source  of  interference. 

The  factor  of  atmospheric  disturb- 
ance is  a  universal  one,  but  varies  during 
certain  parts  of  the  day  and  is  more 
prevalent  in  summer  than  in  winter. 
It  is  commonly  known  that  reception 
over  great  distances  is  made  difficult, 
if  not  entirely  impossible  during  the  sum- 
mer months  because  of  atmospheric 
disturbances.  It  has  also  been  demon- 
strated that  reception  is  greatly  enhanced 
on  a  clear,  cold  night.  A  brief  considera- 
tion of  the  electrical  constitution  of  the 
atmosphere  is  necessary  in  order  to  clear- 
ly understand  the  phenomenon  known  as 
static. 

The  atmosphere  contains  a  distributed 
positive  charge,  which,  as  a  whole,  ap- 
proximately equals  the  permanent  nega- 
tive of  the  earth.  Franklin  proved  that 
there  was  a  difference  of  potential  be- 
tween the  earth  and  the  atmosphere 
when  he  succeeded  in  drawing  a  spark 
from  the  cord  which  was  holding  his 
kite.  The  regular  increase  in  voltage 
between  the  earth  and  the  air  at  various 
heights  is  called  the  potential  gradient. 
The  vertical  potential  gradient  varies 
between  thirty  volts  per  foot  at  the 
earth's  surface  and  one  volt  per  foot  at 
the  height  of  six  miles.  This  condition 
of  the  air  is  generally  conceded  to  be  due 
to  ionisation  of  the  gases  which  compose 
the  earth's  atmosphere,  by  cathode 
rays  or  other  corpuscles  from  the  sun 
and  radio-active  constituents  of  the 
earth's  crust.  The  process  of  ioniza- 
tion consists  of  breaking  up  the  atoms 
which  constitute  these  atmospheric  gases. 
When  an  atom  is  broken  up  into  its  con- 
stituents, the  result  is  a  positive  charge  of 
electricity  and  a  number  of  negative 
charges  or  electrons. 

How    Ions   Recombine 

A  S  THE  relative  position  between  the 
-^*-  earth  and  the  sun  changes,  it  is  evi- 
dent that  the  extent  of  ionisation  will  vary 
to  a  considerable  extent.  In  other  words, 
the  ions  recombine  rapidly  as  soon  as  the 
force  which  caused  this  condition  has 
ceased.  This  de-ionisation  or  recombin- 
ing  of  the  ions  to  form  gas  atoms  will 
change  the  amount  of  electrical  charge 
in  the  air.  It  is  the  change  in  amount  of 
electrical  charge,  or  change  of  potential 
gradient,  which  causes  the  electrical  dis- 
turbance or  noises  in  the  radio  receiving 
set  which  are  commonly  known  among 
radio  operators  as  "grinders."  These 
grinders  travel  over  great  distances  and 
are  more  noticeable  at  night  just  after 
sunset,  because  it  is  then  that  the  pro- 
cess of  de-ionisation  is  at  its  height.  The 
potential  gradient  may  also  be  varied  by 
vertical  air  currents,  which  are  caused 
by  the  sun's  rays  heating  and  expanding 
the  upper  layers  of  the  atmosphere. 
During  the  summer  months,  when  the 
sun  is  relatively  close  to  the  earth,  the 
extreme  heat  will  cause  the  air  to  shift 
vertically  as  already  explained,  thereby 
(Turn  to  page  95) 


RADIO  AGE  for  August,  1925 

Some  Radio 
Luminaries 

and  Why 


The  Magazine  of  the  Hour 


17 


Drake  Stuiio  Photo.  Chicaeo 

WHO  hasn't  heard  the  McCormack-like  voice  of  Sandy 
Meek  trilling  from  the  antennae  of  prominent  Middle- 
Western  radio  stations?  Very  few,  we'll  wager,  for  Sandy  has 
covered  a  lot  of  ground  lately,  specializing  in  Scottish  and 
popular  ditties  from  WBBM,  WHT  and  WQJ,  Chicago,  also 
having  appeared  on  RADIO  AGE  programs  at  KYW.  The 
demure  miss  at  the  right,  in  case  you  aren't  a  movie  fan,  is  Miss 
Carol  Dempster,  leading  lady  of  the  D.  W.  Griffith  stock  com- 
pany. She  told  of  some  of  her  harrowing  experiences  lately 
when  she  appeared  before  the  "mike"  at  WBCQ,  the  Grebe 
station  at  Richmond  Hill,  L.  I. 


WALTER  WIL- 
SON, "Uncle 
Bob, "the  kiddies'bed- 
time  idol  at  KYW,  is 
shown  spending  a 
good  part  of  his  time 
in  the  admirable  oc- 
cupation of  teaching 
school  children  the 
doctrine  of  "The 
Curb  is  the  Limit,  so 
stay  off  the  streets." 
He  has  signed  up 
more  than  50,000  chil- 
dren in  his  campaign. 
His  goal  is  100,000. 
More  power  to  you, 
Walter! 


18 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


Radio  Age  Announces 

A  PRIZE  CONTEST 

For  the  Readers  of  This  Magazine  and  Particularly  the  Followers  of  the  Pickups  and 
Hookups  Department;  Awards  to  be  Made  Monthly  to  Lucky  Winners! 


WHEN  all  the  radio  set  build- 
ers are  busily  engaged  in 
making  up  the  world  beater 
for  the  Winter  session  of  DX  chas- 
ing, or  substituting  quality  for 
quantity  for  the  benefit  of  the 
family,  it  behooves  this  department 
to  get  busy  with  a  matter  that  is  of 
interest  both  to  us  and  the  readers. 
This  matter  is  the  subscription  list 
of  the  magazine. 

Idly  gazing  over  our  subscription 
list  the  other  day,  we  observed  some 
very  strange  things.  For  instance, 
we  have  least  subscribers  in  Miss- 
issippi and  New  Mexico.  There 
might  be  a  reason  for  a  paucity  of 
subscribers  in  Mississippi,  for  we 
can  well  remember  as  far  back  as 
1912  when  that  state  always  was  a 
hard  one  for  radio,  for  what  reason 
we  do  not  know,  but  assume  on  ac- 
count of  the  "delta  static"  which 
manyof  theold  timers  willremember. 
Whether  this  same  reason  could 
be  ascribed  for  the  poor  showing  in 
New  Mexico  is  not  known.  We  do 
not  believe  these  conditions  should 
be  allowed  to  govern,  and  with  this 
and  other  figures  in  mind,  we  are 
starting  a  subscription  contest  for 
the  benefit  of  the  Pickups  and  Hook- 
ups readers  (and  of  course  all  RAD  10 
AGE  readers.) 

Monthly  Prizes 

THE  contest  will  take  the  form 
of  monthly  prizes  given  for  the 
RADIO  AGE  reader  who  sends  in 
the  greatest  number  of  subscriptions 
for  a  given  month.  The  contest  is 
to  be  started  during  the  month  of 
August.  ThereadergetsthisRADIO 
AGE  by  the  15th  of  July  and  will 
be  in  position  to  compete  for  the 
August  prizes. 

First  prize  for  the,  RADIO  AGE 
reader  sending  in  the  greatest  num- 
ber of  paid  up  subscriptions  to  the 
magazine  during  the  month  of 
August  will  be  a  .0005  mfd  ultra- 
low  loss  variable  condenser.  You 
have  probably  seen  it  pictured  on 
many  occasions  in  the  advertising 
pages  of  RADIO  AGE. 


The  second  prize  will  be  a  year's 
subscription  to  RADIO  AGE  for  the 
reader  sending  in  the  second  largest 
number  of  subscriptions,  and  for  the 
third  prize  a  six  months'  subscrip- 
tion to  RADIO  AGE  will  be 
awarded.  If  you  are  already  a  sub- 
scriber your  subscription  will  be 
extended  for  the  period  of  the  prize 
you  win. 

A  Fertile  Field 

MANY  of  you  have  countless 
friends  who  are  readers  and  yet 
not  subscribers  of  RADIO  AGE. 
This  is  a  very  fertile  territory  for  you 
to  work.  Another  is  the  occasional 
reader  of  the  magazine  upon  whom 
you  can  exert  your  wiles.  The  ladies 
are  not  exempt  from  the  attraction 
of  RADIO  AGE,  as  you  have  ob- 
served from  the  many  letters  they 
have  sent  in. 

Despite  the  fact  RADIO  AGE  has 
a  very  flattering  news-stand  sale, 
nevertheless  it  seems  to  us  that  we 
would  become  much  more  like  a 
family  circle  if  the  number  of  annual 
subscribers  were  increased.  So  many 
times,  through  one  reason oranother, 
you  will  fail  to  get  your  copy  of  the 
paper  at  a  news-stand,  whereas  by 
being  a  subscriber  you  can  always 
count  on  having  the  postman  deliver 
your  favorite  radio  magazine  to 
your  home  or  office  once  a  month. 

A  Family  Affair 

WHILE  the  contest  is  intended 
for  all  readers  of  RADIO  AGE, 
at  the  same  time  it  is  believed  that 
our  Pickups  and  Hookups  readers 
are  the  ones  most  interested  in  the 
award  of  prizes,  since  they  belong 
to  that  indefatigable  band  of  ex- 
perimenters who  are  never  content 
to  let  radio  stagnate,  but  who  by 
their  innate  curiosity  are  forever  led 
into  trying  this  and  that  combina- 
tion of  circuits;  of  tinkering  to  see 
what  makes  the  thing  tick.  All  of 
this  labor,  some  mental  and  some 
physical,  is  contributing  toward 
the  advancement  of  the  art;  for- 
after  all,  it  is  truly  an  art.     And, 


incidentally,  if  you  will  stop  to  con- 
sider, it  is  the  only  art  in  existence 
in  which  there  are  so  many  devotees 
scattered  over  the  four  corners  of 
the  globe,  all  intent  upon  making 
some  discovery  or  improvement  that 
will  not  only  reflect  credit  upon  the 
worker,  but  simplify  the  game  for 
the  benefit  of  the  millions  now 
interested  in  it. 

A  Worthy  Project 

FOR  that  reason  we  believe  the 
Pickups  and  Hookups  readers 
will  be  interested  not  only  in  making 
a  fight  to  win  the  monthly  prizes, 
but  will  as  well  be  glad  to  increase 
the  number  of  subscribers  to  the 
magazine  and  thus  increase  the 
family  circle.  More  subscribers  mean 
more  readers  of  this  department; 
more  readers  mean  more  contribu- 
tions ;  more  contributions  mean  more 
data  and  information  for  you,  and 
more  information  for  you  means 
your  quicker  advancement  in  the 
game.  So  it  is  something  worth 
while  for  you  to  strive  for  both  from 
the  remuneration  involved  and  the 
mental  satisfaction  in  learning  more 
and  more  of  the  most  interesting 
study  in  the  world. 

And  the  holders  of  the  D.  T.  but- 
tons who  have  striven  for  distance 
and  succeeded  should  now  have  an 
added  incentive  in  doing  what  they 
can  to  spread  out  the  scope  of  their 
favorite  journal,  which  is  even  now 
read  on  the  two  continents  and 
many  of  the  island  countries  of  the 
world. 

On  your  toes,  readers  of  this  de- 
partment, and  let's  see  what  you 
can  do!  First  prize,  the  .0005  mfd 
ultra-low  loss  variable;  second  prize, 
a  year's  subscription  to  your  maga- 
zine; third  prize,  a  six  months'  sub- 
scription. These  prizes  are  for  the 
men  and  women  who  send  in  the 
greatest  number  of  paid  up  sub- 
scribers to  RADIO  AGE  during  the 
month  of  August.  Returns  must  be 
in  by  the  last  day  of  August  so  we 
can  make  prompt  award  of  the 
prizes. 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


19 


-=^J 


^^ft^^  JPiclk.  ^  ups 

Hook-ups 


% 


THE  material  appearing  under  the  title  "Pickup3  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  is 
contributed  by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


MANY  ITEMS  of  interest  will  be 
found  in  this  department  for 
August,  on  account  of  the  in- 
dustry of  our  contributors.  The  Summer 
months  are  unquestionably  the  ones 
when  all  the  revamping  of  sets  should  be 
accomplished  and  any  new  ideas  tried 
out,  so  the  final  set  will  be  in  excellent 
condition  for  the  Winter  months. 

Several  of  our  readers  have  written  in 
asking  for  a  method  of  drilling  glass 
panels.  While  it  is  a  ticklish  job,  it  can 
be  done.  The  safest  way  is  to  have  a 
wooden  template  to  fit  over  the  glass 
panel,  with  holes  bored  in  the  wood  for 
the  positions  you  want  them  to  occupy 
on  the  glass.  Then  take  a  rat -tail  file  and 
on  an  emery  wheel  grind  one  end  down 
to  a  chisel  edge.  Then  insert  it  in  a 
hand  brace  (not  the  egg  beater  type  of 
hand  drill,  but  the  brace  and  bit  type). 
Put  a  little  three-in-one  oil  or  turpen- 
tine on  the  place  to  be  drilled,  and  start 
drilling.  It  is  somewhat  of  a  laborious 
process,  but  if  you  must  have  glass 
panels,  you  must  pay  the  price  in  man- 
ual labor.  The  wooden  template  serves 
to  keep  the  drill  from  slipping  sideways. 

Toroid  Coils 

Our  request  for  data  from  those  who 
have  tried  to  build  the  toroid  coils  has 
not  been  in  vain,  for  we  hardly  had 
uttered  the  request  when  George  B. 
Hostetter,  Box  225,  Freewater,  Oregon, 
came  to  the  rescue  of  our  readers  with 
two  pictures  and  a  descriptive  article 
of  how  he  made  his  toroid  coils,  which 
article  we  are  including  in  this  month's 
department. 

One  of  our  traveling  readers  has  sent  in 
pictures  of  his  portable  set.  R.  E.  Cox's 
contribution  will  also  be  found  in  this 
section. 

Naturally  enough,  many  of  the  poten- 
tial DT  button  aspirants  will  not  be 
quite  as  active  during  this  month  unless 
they  confine  their  activities  to  the  sta- 
tions heard  on  a  portable  while  on  their 
vacation.  It  would  not  be  surprising  if 
we  had  just  a  few  of  the  button  seekers 
this  month,  but  we  know  they  will  be 
back  with  full  force  within  the  next 
month  or  so  when  the  weather  begins 
getting  back  to  normal  as  far  as  radio  is 
concerned. 

From  Francis  Dickie,  Heriot  Bay, 
British  Columbia,  Canada,  we  have  a 
picture  of  a  radio-tester;  a  little  device 
well  known  to  the  craft  for  use  in  testing 
for  "opens"  in  coils  and  other  purposes. 
A  picture  and  a  short  description  of  the 


Name 
R.  A.  Ganatt. 

George  B.  Hostetter 

CONTRIBUTORS 
Address 
—17  Lome  Road,  London... 
...Box  325 

City 
N.  4,  England. 
..Freewater,  Ore. 

...Heriot  Bay. 

..B.  C.  Canada 

P.  E.  Chapman 

R.  E.  Cox._  

...805  N.  Preston  St „ 

...Douglas  Shoe  Co... 

West  Philadelphia,  Pa. 
..Brockton,  Mass. 

A.  E.  Hodson.-  

...139  Rawson  St.,  Farnswoi 

■th, 
S.  E.  Lancashire,  England 

..Grand  Island,  Neb. 
..Evans,  Colo. 

DIAL  TWISTERS 
...122  South  White  St 

Harold  Adams 

B.  R.  Cadman.  

Shirley  L.  Travis 

...3096  Bacon  Road.         

...50  West  Genesee  St     

Berkeley,  Mich. 
Hornell,  N.  Y. 
..Kimball,  South  Dakota 

Charles  Hrdlicka.  

..  69  Vedado  Way 

Atlanta,  Ga. 
..Liverpool,  England 

Chicago,  111. 
...Viroqua,  Wis. 

W.  J.  Sergent,  Jr 

Charles  A.  Wilson. 

Robert  A.  Fulton 

25  Spellow  Lane,  Walton. 
...2674  Burling  St 

Harold  Beaman.  

...95  Sherwood  St 

...Ottawa,  Ont.,  Canada 

W.  M.  Patterson.  

Hans  G.  Hirsch. 

1003  Indiana  Ave 

...P.  O.  Box  993 

..Monaca,  Pa. 
.Havana,  Cuba 

1320  N.  14th  St 

East  St.  Louis.  111. 

outfit  is  given  for  the  benefit  of  our  read- 
ers. 

Real    DX    Work 

Recently  we  spoke  of  the  long  distance 
achievement  of  E.  H.  Scott,  who  heard  all 
manner  of  American  signals  from  Tas- 
man,  Nelson,  New  Zealand.  In  connec- 
tion with  this  matter  we  note  that 
KFRU,  owned  by  the  Etherical  Radio 
Co.,  at  Bristow,  Okla.,  considers  this 
reception  the  longest  distance  from  which 
"The  Voice  of  Oklahome"  has  been  re- 
ported, according  to  a  letter  received  in 
our  office  from  Roy  C.  Griffins,  the  direc- 
tor of  that  station. 

RADIO  AGE  is  always  glad  to  receive 
letters  like  the  following  from  Rhea 
Pearce,  69  Vedoda  Way,  Atlanta,  Ga., 
for  we  are  then  sure  we  are  on  the  right 
track  as  regards  things  that  interest  and 
satisfy  our  readers.  After  sending  in  his 
remittance  for  another  year's  subscrip- 
tion to  the  magazine,   Mr.   Pearce  says: 

"I  think  RADIO  AGE  is  the  best 
on  radio  I've  seen.  Your  hookups  are 
good  and  I've  built  sets  by  a  lot  of  them 
and  they  always  work."  The  last  three 
words  are  most  appreciated  because  we 
have  always  tried  to  adhere  to  a  policy 
of  not  giving  space  to  sets  which  have 
only  been  constructed  in  the  mind.  We 
could  tell  you  a  lot  of  things  about  re- 


ceivers built  in  the  mind  which  were 
given  space  in  radio  periodicals.  However, 
such  a  practice  has  only  served  to  make 
us  more  firm  in  our  determination  not  to 
publish  anything  that  has  not  been 
built,  tested  and  found  effective  for  the 
purpose  for  which  it  is  intended. 


Dial  Twister  P.  E.  Chapman,  805 
North  Preston  St.,  West  Philadelphia, 
Pa.,  who  is  greatly  interested  in  the 
application  of  portables  to  a  canoe,  has 
Written  us  telling  of  his  scheme  of  com- 
bining pleasure  on  the  water  with  radio. 
He  uses  a  standard  variometer  hooked 
up  after  the  fashion  of  the  ultra-audion 
with  two  stages  of  amplification.  Using 
"199"  tubes,  he  finds  this  set  weighs  little 
and  occupies  a  very  small  space  in  the 
canoe.  With  a  six  foot  piece  of  copper 
wire  (bare)  dangling  in  the  water  and 
without  an  antenna,  Mr.  Chapman 
finds  this  set  will  give  loud  speaker 
volume  on  local  stations  in  Philadelphia 
so  the  music  can  be  enjoyed  on  the  lake. 
His  set  was  assembled  at  a  cost  of  S16.83 
and  a  diagram  of  the  circuit  is  shown 
elsewhere  in  this  department.  The 
assembly  is  left  to  the  individual  needs 
of  the  builder. 


Charles      Hrdlicka,      Kimball,      South 
Dakota,    has   epitomized   the   experience 


20 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


of  all  radio  fans  in  the  words  with 
which  he  describes  his  receiver.  He  says, 
"I  attribute  the  success  of  the  receiver 
to  the  fact  that  high  class  material  is 
employed  throughout." 

There  is  no  question  that  the  best  is 
none  too  good  for  our  modern  receivers 
when  we  strain  to  make  each  tube  and 
its  associated  parts  do  its  full  duty. 
Mr.  Hrdlicka  is  using  a  five  tube  Weagant- 
Reinartz  described  in  the  May  RADIO 
AGE,  with  the  last  two  tubes  arranged 
push-pull  for  quality.  His  list  of  sta- 
tions automatically  gives  him  the  coveted 
button. 


at  122  S.  White  St.,  Grand  Island,  Neb., 
is  Leland  Steele,  who  sends  in  a  dandy 
list  of  stations.  He  is  another  of  the 
RADIO  AGE  addicts  who  tells  us  that 
every  set  he  has  made  from  blueprints 
in  our  magazine  works,  and  works  fine. 
Another  DT  added  to  the  ever  increasing 
family  of  distance  hounds. 


Shirley  L.  Travis,  SO  West  Genesee  St., 
Hornell,  N.  Y.,  sends  in  an  interesting 
list  of  stations  picked  on  a  receiver  of  the 
factory  built  type,  which  list  also  entitles 
him  to  entrance  into  the  family  of  Dial 
Twisters. 


B.  R.  Cadman,  3096  Bacon  Road, 
Berkeley,  Mich.,  informs  us  of  the  suc- 
cess he  has  had  with  the  set  he  con- 
structed from  an  article  in  RADIO 
AGE,  in  May,  1924.  He  says  he  has 
made  a  number  of  sets  since  that  time, 
but  always  goes  back  to  his  first  love  for 
distance  work,  which  is  a  converted 
single  circuit  with  two  stages  of  audio. 
We  are  glad  to  see  that  Mr.  Cadman 
believes  in  converting  the  single  circuit, 
for  we  know  of  thousands  who  are  often 
of  the  same  opinion,  especially  on  the 
nights  when  lean  signals  and  fat  regenera- 
tive whistles  do  not  mix  well.  His 
efforts  in  tuning  also  merit  DT  recogni- 
tion, so  Mr.  Cadman  getsthelittlebutton. 


Harold  Adams,  who  lives  at  Evans, 
Col.,  sends  in  a  list  of  Eastern  and 
Western  stations  that  permits  him  to 
become  a  member  of  the  dial  twisting 
fraternity.  He  does  not  state  his  type 
of  receiver,  but  he  has  the  stations  to 
show  for  it,  so  it  must  be  all  right. 


Another   ultra-audion   fiend   who   lives 


From  across  the  pond  our  English 
cousins  have  furnished  us  a  bit  of  news, 
which  is  very  interesting.  The  writer 
is  R.  A.  Ganatt,  17  Lome  Road,  London 
N.  4,  who  tells  us  of  the  great  British 
DX  movement.  Knowing  that  our  read- 
ers" are  keenly  alive  to  the  quickening  of 
the  radio  pulse  abroad,  we  are  printing 
Mr.  Ganatt's  communication  in  full. 
It  follows: 

"There  is  a  great  DX  movement 
amongst  the  British  fans  for  the  Summer 
months,  and  already  many  ambitious 
plans  have  been  made.  At  last  the 
British  radio  fan  is  feeling  how  much  he 
is  missing  by  not  putting  more  enthus- 
iasm into  radio.  Up  to  the  present 
it  has  been  a  half-hearted  attempt,  but 
now  things  are  beginning  to  move. 

"Capt.  Eckersley  has  aroused  all  self- 
respecting  fans  in  talks  given  from  Lon- 
don, and  he  gives  the  impression  that 
only  about  five  people  in  every  hundred 
who  listen  want  to  get  DX.  This  is 
absurd.  Britain  wants  to  listen  in  more 
than  she  ever  did  to  American  and  foreign 
broadcasting,  and  she  is  now  putting  her 
shoulder  to  the  wheel  and  before  long  she 
will  get  what  she  wants. 

"The  spirit  of  enthusiasm  is  getting 
hold  of  the  British  bug  properly,  and  he 
feels  himself  endowed  with  greater 
strength  toward  this  effort.  This  trans- 
formation has  been  in  force  only  for  a 
week  or  two,  and  already  its  effects  are 
being  felt.  Heretofore  the  British  fan 
did  not  go  in  for  anything  like  DX  and 
was  content  to  listen  to  the  only  programs 
available,  and  these  local  ones  at  that. 

"Manufacturers  and  dealers  agree 
that    an    unprecedented    rush    for    radio 


sets  and  parts  has  occurred  during  the 
past  few  weeks.  This  seems  unusual, 
in  view  of  the  Summer  months,  but  it  is  a 
fact,  nevertheless.  Multi-tube  sets,  sup- 
er-hets,  neutrodynes  and  the  like  are 
commanding  the  attention  of  the  British 
amateurs.  The  fans  are  feeling  ashamed 
of  themselves,  and  on  the  quiet  are  say- 
ing, 'I'm  not  going  to  let  my  American 
cousins  put  it  over  me.'  " 

And  finally  Mr.  Ganatt  gives  us  warn- 
ing that  the  movement  is  bound  to  suc- 
ceed, and  for  us  to  be  on  our  guard, 
for  the  British  say  they  refuse  to  be  a 
bunch  of  "radio  boobs"  any  more. 

There  is  no  question  but  the  continen- 
tal attitude  in  high  places  towards  radio 
has  resulted  in  keeping  down  the  en- 
thusiasm of  the  radio  public,  but  once 
feeling  their  oats,  there  is  no  reason  why 
the  millions  of  listeners  in  the  British 
Isles  should  not  take  matters  into  their 
own  hands  and  bring  about  conditions 
parallel  to  those  in  existence  in  the 
United  States,  provided  they  desire  that 
kind  of  conditions.  More  power  to  our 
British  experimenters  and  DX  seekers. 


Speaking  of  conditions  in  England,  we 
have  a  letter  from  A.  E.  Hodson,  139 
Rawson  St.,  Farnsworth,  S.  E.  Lanca- 
shire, England,  reporting  his  reception  of 
KDKA,  WGY,  WBZ  and  CKAC,  to- 
gether with  a  number  of  continental  sta- 
tions. He  sends  in  a  hookup  very  popular 
with  the  British  fans,  which  is  printed 
at  the  bottom  of  this  page. 


Some  of  our  radio  friends  are  terrified 
at  the  prospect  of  the  combine  using 
some  sort  of  a  hashing  machine  to  make 
broadcast  music  unreadable  except  to 
those  owning  a  receiver  put  out  by  the 
radio  trust.  This  subject  has  had  some 
attention  from  contemporary  radio  maga- 
zines, but  so  far  the  matter  does  not 
seem  to  be  as  terrifying  as  it  sounds. 
Within  thirty  days  after  the  first  hashing 
machine  goes  to  work,  its  circuit  and 
constants   would   be   known    and   within 


/TV 


„,<} 


r  r  1 


FoMa 


+B 


T+     111- 


-8 

A 

•   +A 


r>a    T 


This  is  the  general  type  of  tuned  radio,  detector  and  one  stage  of  audio  amplification  in  use  in  the  British  Isles.     It  is  sent  in  by 
A.  E.  Hodson,  139  Rawson  St.,  Farnsworth,  S.  E.  Lancashire,  England. 


RADIO  AGE  for  August,  192; 


The  Magazine  of  the  Hour 


21 


another  thirty  days  a  goodly  number  of 
experimenters  would  have  receivers  of 
their  own  rigged  up.  From  that  point 
it  is  easy  to  see  that  such  a  scheme  of 
broadcasting  only  for  the  benefit  of  the 
privileged  few  will  hardly  ever  come  to 
pass. 

There  is  hardly  a  thing  that  has  been 
invented  that  has  not  had  something 
come  along  later  to  either  improve  it  or 
nullify  its  usefulness.  And  the  prospect 
of  piping  music  into  the  home,  which 
was  done  as  early  as  1912,  might  seem 
rosy  at  first  blush,  but  a  little  sober 
reflection  will  produce  the  thought  that 
the  one  tie  that  binds  in  radio  is  the 
ability  of  the  set  owner  to  pick  programs 
at  will,  and  not  have  them  thrust  upon 
him  willy-nilly.  So  it  does  not  seem 
there  will  be  much  of  a  change  in  the 
status  of  broadcasting.  Those  who  de- 
rive an  advertising  benefit  from  the 
transmitters  can  hardly  expect  the  public 
to  contribute,  when,  after  all,  the  amount 
of  money  tied  up  in  receivers  and  allied 
apparatus  probably  overshadows  by  a 
great  deal  the  total  involved  in  the 
ownership  and  operation  of  broadcast 
transmitters. 


The  circuit  shown  in  Fig.  1  can  be 
made  up  with  honeycombs  for  covering  a 
wider  span  of  wavelengths  than  the 
broadcast  band.  Otherwise  it  can  be 
made  up  in  the  low  loss  type  of  winding. 
The  detector  is  regenerative.  This  type 
of  circuit  is  in  use  in  the  British  Isles  on 
account  of  regulations  preventing  a 
regenerative  set  coupled  to  an  antenna. 
Some  of  our  English  friends  tell  us  in 
letters  that  despite  the  ban  against 
regenerative  sets  there  are  a  multitude 
of  squeals  to  be  heard  over  there.  This 
is  the  set  with  which  Mr.  Hodson  heard 
KDKA,  WGY,  WBZ  and  CKAC,  to- 
gether with  a  bunch  of  broadcasting 
stations  on  the  Continent. 


William  J.  Sergent,  Jr.,  25  Spellow 
Lane,  Walton,  Liverpool,  England,  sends 
in  a  DX  list  that  certainly  gives  him  the 
button.  He  also  heard  KDKA,  WGY 
and  WBZ  using  a  four  tube  set,  one 
radio,  detector  and  two  audio,  built 
along  the  lines  as  Mr.  Hodson 's  shown  in 
Fig.  1.  He  also  uses  a  one  tube  receiver 
with  two  stages  of  audio  and  on  it  does 
most  of  his  DX  work.  He  is  particularly 
desirous  of  getting  an  extremely  selective 
set  using  four  tubes.  Maybe  some  of  our 
Pickups  readers  can  give  him  a  circuit 
that  will  do  hair-breadth  tuning. 


The  device  shown  in  Fig.  2  is  a  radio- 
tester,  manufactured  by  the  British 
Industries  Association,  317  High  Hol- 
born,  London,  W.  C.  I.  It  consists  of  a 
dry  cell,  a  small  lamp  and  a  series  con- 
nection arranged  so  that  continuity 
of  wiring  may  be  tested  in  inductances, 
transformers,  phones,  rheostats,  poten- 
tiometers; it  can  also  be  arranged  to  test 
condensers.  A  similar  device  in  the 
workshop  of  the  experimenter  will  save  a 
lot  of  trouble  in  testing.  The  illustra- 
tion is  sent  in  by  Francis  Dickie,  Heriot 
Bay,  British  Columbia,  Canada. 


Fig.  2.    A  neat  and  efficient  means  of  testing  for  breaks  in  wiring  of  sets,  which  can  be 

applied  to  almost  any  use  in  determining  the  continuity  of  wiring  in  coils,  transformers, 

phones,  and  other  apparatus. 


Previous    mention    has    been    made    of 
the  contribution  of  George  B.  Hostetter, 


Box  325,  Freewater,  Oregon,  who  tells 
readers  of  this  department  how  to  make 
the  toroid  coils  for  use  in  radio  frequency 
sets.     The  process  is  as  follows: 

Procure  a  cardboard  tube  one  and  a 
quarter  inches  in  diameter  and  about 
nine  or  ten  inches  long.  This  is  shown 
at  G  in  the  photograph,  Fig.  3.  On  this 
wind  a  layer  of  ordinary  twine  string  (B  in 
photograph)  fastening  the  end  with 
a  tiny  piece  of  adhesive  tape,  A.  Over 
this  fasten  a  thickness  of  writing  paper. 
Get  a  roll  of  half  inch  adhesive  tape  and 
cut  off  a  piece  about  21  inches  long. 
Split  each  end  of  this  piece  for  a  distance 
of  about  seven  or  eight  inches.  Lay  the 
tape  length-wise  on  the  tube,  sticky- 
side  out,  pushing  the  split  edges  into 
the  ends  of  the  tube  out  of  the  way. 
Now  wind  on  225  turns  of  No.  24  SCC 
wire,  D  and  Dl  in  the  picture,  securing 
the  ends  by  punching  a  hole  in  the  tape. 

Lay  one  of  the  quarter-inch  pieces  of 
tape  back  over  the  coil  and  the  opposite 
quarter-inch  piece  on  the  other  end  of  the 
coil,  so  as  to  form  a  strip  a  half  inch 
wide  over  the  top  of  the  coil. 

About  a  quarter  of  an  inch  from  the  end 
of  this  winding,  start  the  primary,  wind- 
ing four  turns  of  the  same  wire  (El). 
Do  not  break  the  wire,  but  run  it  along 
the  tape  for  two  and  a  half  inches,  then 
wind  four  turns  more  (E2),  run  along 
the  tape  again  for  two  and  a  half  inches, 
and  wind  four  more  turns  (E3).  This 
makes  twelve  turns  in  all  for  the  primary. 
Each  coil  of  four  turns  should  be  held 
temporarily  in  place  with  a  small  piece 
of  adhesive  tape. 

Now  take  the  two  other  pieces  of 
quarter  inch  tape  and  stick  them  tightly 
in  place  over  the  primary  as  at  (F). 

Pull  the  tape  (A)  loose  and  unwind  the 
string,  pulling  it  out  the  end.  This  will 
allow  the  coil  to  slip  off  the  tube  very 
easily.  Then  the  layer  of  writing  paper 
may  be  removed. 

Cut  a  piece  of  light-weight  cardboard 


an  inch  wide  and  bend  it  into  a  ring 
whose  outside  diameter  is  exactly  equal 
to  the  length  of  the  secondary  coil 
measured  on  the  tape.  Cut  two  circles  of 
heavy  cardboard  two  and  a  half  inches  in 
diameter.  Glue  the  ring  to  these  disks, 
forming  a  spool  as  shown  in  the  upper 
part  of  Fig.  3. 

With  a  piece  of  adhesive  tape  fasten 
one  end  of  the  coil  to  the  spool,  bring 
the  other  end  of  the  coil  around  until 
the  ends  fasten  together  with  another 
piece  of  tape,  working  between  the  turns 
of  the  coil,  which  may  be  straightened 
back  into  place  after  the  ends  have  been 
secured.  You  will  now  have  a  coil  as 
shown  in  Fig.  4.  The  leads  may  be 
brought  out  through  holes  punched  in 
the  disks  as  shown.  These  coils  may  be 
used  in  any  tuned  radio  frequency 
circuit.  They  eliminate  special  placement 
of  coils  or  the  use  of  stabilizing  devices. 

Another  traveling  man,  this  time  R.  E. 
Cox,  who  travels  for  the  W.  L.  Douglas 
Shoe  Co.,  Brockton,  Mass.,  and  who 
writes  from  Coldwater,  Mich.,  shows  us 
how  it  is  possible  to  always  be  in  touch 
with  the  world  by  means  of  a  portable 
which  he  carries  with  him  on  all  his 
trips. 

In  Figure  5  is  shown  the  receiver, 
which  uses  the  circuit  around  which 
Browning-Drake  have  developed  a  re- 
ceiver, while  Figure  6  shows  the  self 
contained  set  being  carried  by  Mr.  Cox, 
whose  northern  extremities  were  not 
shown,  since  he  was  more  desirous  of 
showing  us  the  set  than  himself.  Mr. 
Cox  tells  us  the  set  has  four  tubes,  the 
fifth  being  in  parallel  with  the  fourth. 
He  gets  excellent  results  and  is  strong 
for  RADIO  AGE. 

For  essentially  local  work  in  a  canoe, 
where  weight  is  a  consideration,  the  set 
shown  in  Fig.  7,  contributed  by  Mr. 
Chapman,  might  be  of  interest  to  readers 
with  aquatic  proclivities  in  the  Summer- 


22 


RADIO  AGE  for  August,  1925 


time.  A  six  foot  piece  of  bare  wire 
serves  as  the  ground.  Locals  come  in 
well  on  a  loud  speaker  and  help  con- 
siderably while  out  on  the  lake. 


Charles  A.  Wilson,  2674  Burling  St., 
Chicago,  111.,  went  DX  hunting  on  the 
night  of  March  29,  and  came  forth  with 
a  very  interesting  radio  scalp,  that  of 
4YA,  the  broadcasting  station  of  the 
British  Electric  and  Engineering  Co., 
219  Moray  Place,  Dunedin,  New  Zea- 
land. To  make  sure  there  would  be  no 
mistake,  Mr.  Wilson  communicated  with 
the  company  and  received  due  verifica- 
tion of  the  reception.  While  it  has  be- 
come rather  commonplace  for  the  New 
Zealanders  to  hear  our  American  sta- 
tions, it  is  nevertheless  somewhat  of  a 
fete  for  the  reception  to  be  in  the  oppo- 
site direction.  Both  Mr.  Wilson  and  the 
broadcasting  station  in  New  Zealand  have 
reason  to  feel  proud  of  their  achievement. 


Robert  A.  Fulton,  of  Viroqua,  Wis., 
who,  incidentally,  is  only  eleven  years 
old,  has  qualified  for  a  D.  T.  button  with 
the  list  of  stations  he  sends  in,  all  of 
which  have  been  heard  on  a  home-made 
typically  regenerative  set. 


Using  a  two  tube  ultra-audion  de- 
scribed in  the  March  RADIO  AGE, 
Harold  Beaman,  95  Sherwood  St.,  Otta- 
wa, Ont.,  Canada,  brought  in  a  total  of 
79  stations  from  the  Atlantic  to  the 
Pacific  and  earned  for  himself  an  en- 
blem    of     the     dial    twisting    fraternity. 


W.  M.  Patterson,  1003  Indiana  Ave., 
Monaca,  Pa.,  who  seems  to  be  a  mem- 
ber of  the  A.  R.  R.  L.,  sends  us  a  list  of 
his  DX  results  on  a  single  tuber  which 
allows  him  to  bring  home  the  bacon  in 
the  form  of  the  button.  His  list  of  83 
stations  includes  a  number  of  amateur 
phone    stations. 


The  conductor  of  this  column  has  been 
accused  of  many  things  in  his  career 
but  never  yet  has  he  qualified  as  a  mind 
reader.  The  reason  for  the  foregoing  is 
the  receipt  of  a  letter  from  a  radio  en- 
thusiast whose  address  is  Route  C,  Box 
141,  Frederick,  Oklahoma.  The  corres- 
pondent neglected  to  sign  his  name  to 
the  letter,  and  as  a  consequence  we  have  a 
Dial  Twister's  button  issued  to  an  ad- 
dress instead  of  an  individual.  If  the 
resident  of  the  address  given  above  will 
communicate  with  us,  we  shall  be  glad  to 
send  him  the  button  which  he  has  merited 
through  the  DX  list  sent  in. 


Making  up  a  "Baby  Het"  from  speci- 
fications in  RADIO  AGE  and  adding  a 
stage  of  audio  for  increased  volume, 
Hans  G.  Hirsch,  P.  O.  Box  993,  Havana, 
Cuba,  is  having  the  time  of  his  life 
logging  them  from  coast  to  coast.  His 
list  is  a  fine  one,  especially  when  many  of 
our  readers  imagine  that  residents  of  the 
Gulf  section  are  continually  fighting 
static:  We  will  give  him  the  button 
as  an  indication  that  static  does  not  mean 
much  in  the  existence  of  a  real  distance 
seeker. 


The  Magazine  of  the  Hour 

U.  S.  Bureau  of  Standards.  Copies  ot 
this  paper  may  be  secured  from  the 
Superintendent  of  Documents,  Govern- 
ment Printing  Office,  Washington,  D.  C, 
for  5  cents. 


The  conductor  of  this  column  is  taking 
no  chances  of  your  failing  to  read  about 
the  subscription  contest,  which  has  been 
started  by  Radio  Age  and  accordingly 
calls  your  attention  to  the  full  details 
on  page  18  of  this  number.  Dial  Twisters 
are  especially  invited  to  take  part  in  the 
contest  because  of  the  nature  of  the 
prizes  and  because  of  the  fact  that  read- 
ers of  this  department  are  the  ones  most 
interested  in  the  creation  of  a  larger 
Radio  Age  family  which  will  naturally 
be  followed  by  much  more  interesting 
data   in    these   columns. 


Fig.  4.    Here  is  shown  the  toroid  as  it  looks 

when   completed.     A  careful  study  of  the 

accompanying   description    will  show  you 

how  to  do  it  nicely. 

tactics  of  the  Octopus,  William  Motyl, 
1320  North  14th  St.,  East  St.  Louis,  111., 
furnishes  us  with  a  DX  list  of  stations 
heard  on  the  regenerative  reflex  described 
in  the  March  blueprint  section.  Mr. 
Motyl  used  a  variometer  with  an  aper- 
iodic primary  instead  of  the  r.  f.  trans- 
former and  a  variable  to  tune  the  r.  f. 
transfomer  proper,  these  two  additions 
helping  out  to  a  considerable  extent  on 
DX.  Another  member  added  to  the  dial 
twisting  family. 


The  a.  c.  tubes,  which  are  being  given 
consideration  in  this  issue  in  an  article 
by  Turner,  should  command  the  atten- 
tion of  our  fans.  Probably  more  research 
is  still  necessary  with  these  tubes,  but 
nevertheless  they  seem  to  point  the  way 
to  the  battery-less  set  of  the  future. 
See  what  you  can  do  with  them  and  let 
us  have  the  dope. 


Those  interested  in  insulating  materials 
may  find  data  of  interest  in  the  techno- 
logical paper  No.  284,  "A  Study  of  the 
seasonal  variation  of  the  r.  f.  phase 
difference  of  laminated  phenolic  insulat- 
ing materials"  by  J.  L.  Preston  and 
E.  L.  Hall,  which  has  been  issued  by  the 


Dial  Twisters  may  be  interested  in 
knowing  that  WGY  may  now  be  found 
on  four  wave  channels,  according  to  a 
recent  announcement.  These  follow: 
WGY  379.5  meters;  2XAF  38  meters; 
2XK  109  meters  and  2XAH  1660  meters. 
The  last  three  groups  of  call  letters  are 
special  experimental  licenses  of  the 
General  Electric.  The  purpose  of  the 
four  channels  is  for  research  work  by 
the  company's  engineers  on  transmis- 
sion problems  under  all  conditions; 
day  and  night,  summer  and  winter. 

Radio  fans  who  are  equipped  to  receive 
on  the  four  wavelengths  are  invited  to 
report  to  the  engineers  the  quality, 
(Turn  to  page  86) 


Patting  our  Editor  on  the  back  for  his     ?*■',    i  ■      I  flclure ,ah°ve  shorws  &e  toroid  cod  wound  on  a  straight  form,  preparatory 
™«il,,ip     stand     =«,=;  ,H      X        •     •/•  to  "J  Uln&  bent  m  lhe    orm  °    a  doughnut.      The  form  shown  at  the  top  is  that  used  in 

reoolute     stand     against     the     insidious  the  final  assembly  cf  the  coil. 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour  23 


Radio  Age  Offers  the  First  Real 
Presentation  of  Basic  Hookups 
in  "De  Luxe  Edition 


Conducted  by  F.  A.  Hill 

IN  putting  forth  the  August  number 
of  RADIO  AGE,  its  publishers  have 
simply  acceded  to  the  demand  on  the 
part  of  radio  fans  for  the  basic  hookups 
from  which  the  various  radio  circuits 
have  been  developed,  without  a  ple- 
thora of  misleading  terms  attached  to  an 
old  circuit  and  put  out  under  a  fancy 
sounding  name.  The  radio  fan  has  come 
to  the  stage  in  this  interesting  science 
where  he  courts  and  welcomes  frankness, 
and  it  is  the  purpose  of  RADIO  AGE  to 
give  the  reader  such  frankness  in  its 
columns. 

In  looking  over  the  crystal  circuits 
shown  by  Mr.  Rathbun  on  page  30  of  this 
section,  you  will  find  all  the  possible 
means  of  hooking  up  a  crystal  set.  These 
forms  have  been  tried  out  by  the  Bureau 
of  Standards  and  measurements  made  to 
enable  the  radio  fan  to  determine  which 
type  he  desires.  The  relative  audibilities 
shown  will  soon  show  the  interested  fan 
which  type  of  hookup  he  wishes  to  use. 
Yet  many  of  the  forms  shown  here  have 
found  their  way  into  the  market  under 
"high-faluting"  names,  some  of  the  indi- 
viduals even  going  so  far  as  to  claim  the 
invention  of  this  or  that  particular 
crystal  circuit.  Such  practices  as  out- 
lined are  not  countenanced  either  by  the 
readers  or  the  publishers  of  a  good  radio 
magazine.  This  is  only  one  of  the  many 
reasons  for  our  publication  of  this 
wonderful  DeLuxe  Edition. 

Another  of  the  reasons  for  its  appear- 
ance is  the  fact  that  many  experimenters 
have  been  stumped  to  find  a  basic  cir- 
cuit when  they  have  been  assailed  on  all 
sides  with  developments,  improvements, 
additions  and  deletions  to  the  standard 
circuits.     Insofar  as  it  is  possible  in  the 


blueprints  shown  herein,  we  are  giving 
the  basic  circuit  and  a  brief  comment  as 
to  its  history  and  its  adaptability  for 
experimentation.  Perhaps  later  experi- 
mentation with  some  of  the  circuits  has 
shown  improvements  can  be  made  by 
slight  deviations  from  the  plans.  Where 
such  is  the  case,  due  mention  will  be  made 
of  the  changes  and  the  reason  for  such 
changes. 

With  the  August  number  of  RADIO 
AGE  in  his  possession,  the  radio  fan  is 
in  a  position  to  start  work  on  the  simplest 
to  the  most  complex  radio  set,  since 
nearly  every  form  of  set  is  shown  basic- 
ally; the  experimenter  only  has  to  use  his 
ingenuity  in  making  up  sets  embodying 
elaborations  or  amplifications  of  the 
basic  data  given. 

The  popularity  of  the  blueprint  sec- 
tion of  the  Radio  Age  each  month  can 
best  be  understood  by  the  flood  of  letters 
from  fans  desiring  to  build  the  sets  de- 
scribed, and  also  from  the  satisfied  set 
builders  who  report  their  success  with  the 
receivers. 

The  correspondence  seems  to  be  pretty 
well  divided  over  the  entire  country, 
including  Canada.  Foreign  countries 
also  furnish  a  pretty  good  volume  of 
letters,  all  testifying  to  the  popularity 
of  the  blueprint  instructions  as  contrasted 
to  the  conventional  black  and  white 
drawings. 

In  following  the  blue  prints  experi- 
menters should  always  remember  that 
for  electrical  connections  the  schematic 
diagram  should  be  followed,  since  the 
other  drawings  are  either  isometric  or 
plan  views  of  the  set  and  are  not  intended 
as  electrical  hookups.  Always  follow 
the  schematic  when  wiring  your  set  and 
you  will  not  make  mistakes. 


In  the  blueprint  section  this  month 
readers  will  find  a  number  of  the  conven- 
tional symbols  which  have  been  drawn  up 
by  Mr.  Rathbun  and  which  should  prove 
of  interest  to  the  fans  who  are  beginning  to 
learn  the  intricacies  of  the  game. 

Readers  following  this  section  closely 
will  see  all  of  the  basic,  hookups  from 
which  the  many  forms  of  circuits  are 
developed.  Any  one  of  the  circuits  can 
be  twisted  around  in  different  ways  as 
far  as  the  material  is  concerned,  but  the 
electrical  characteristics  will  not  change. 
The  substitution  of  variometers  for  tun- 
ing the  plate  circuit  of  a  tube  instead  of  an 
inductance  and  a  condenser  does  not 
change  the  set  from  a  regenerative  set 
into  something  else.  And  so  on  down 
through  the  list. 

In  thinking  over  the  various  items 
which  the  experimenter  will  require  in 
the  assembly  of  the  various  circuits, 
very  careful  consideration  should  be 
given  to  the  use  of  good  material.  There 
has  never  been  any  question  of  the  fact 
that  good  material  will  make  a  set  where 
poor  material  will  ruin  it.  See  that  your 
condensers  and  inductances  are  made  by 
reliable  manufacturers.  Look  over  the 
socket  market  and  pick  out  one  of  the 
type  that  will  give  you  positive  contact 
on  all  the  prongs. 

The  grid  leaks  should  especially  be 
scrutinized  for  in  the  grid  leak  lies  a  great 
deal  of  the  trouble  of  the  set  builders. 
It  might  pay  to  buy  two  or  three  leaks  of 
different  values  just  to  be  sure  you  have  a 
good  one.  The  little  grid  condensers 
should  also  be  good  ones,  preferably 
with  mica  insulation  and  copper  plates 
that  will  not  alter  their  characteristics. 

A  good  deal  of  attention  can  also  be 
paid  to  transformers  and  to  loud  speakers. 


24  RADIO  AGE  for  August,  1925  The  Magazine  of  the  Hour 

A  Timely  Discourse  on 

Conventional  Radio  Symbols  and 
Crystal  Detector  Sets 

By  JOHN  B.  RATHBUN 


CONVENTIONAL  radio  circuit  dia- 
grams, the  short-hand  of  radio,  have 
always  proved  a  sticker  to  the  tyro  in 
this  science,  and  it  is  certain  that  many  a 
prospective  builder  has  contracted  a  bad 
case  of  cold  feet  and  quit  the  game  when 
he  was  brought  face  to  face  with  the 
curley-cues  and  zig-zag  lines  of  the  tech- 
nical diagram.  Not  being  very  familiar 
with  the  apparatus  itself,  it  is  no  wonder 
that  the  prospect  of  learning  still  more 
of  the  technique  filled  him  with  dismay. 
However,  when  these  symbols  are  once 
understood,  they  are  more  easily  read 
and  understood  than  the  picture  diagrams 
for  they  show  the  functioning  and  general 
principles  of  the  circuits  far  more  clearly 
to  the  experienced  eye  than  pictures  of 
the  apparatus.  You  can  see  the  course 
taken  by  the  current  in  the  different 
branches  of  the  circuit  at  a  glance,  and 
can  immediately  classify  the  circuit  with 
little  chance  of  error;  something  that 
I  have  never  yet  been  able  to  do  with  the 
picture  type.  However,  the  picture 
diagram  has  its  place  in  the  scheme  of 
things  where  the  reader  is  not  interested 
in  theory,  but  simply  in  building  some- 
thing that  will  bring  in  the  voice  and 
music  with  the  least  delay  and  study. 

For  the  benefit  of  those  who  have  not 
yet  become  familiar  with  the  standard 
conventional  symbols  used  in  radio  cir- 
cuit diagrams,  I  have  prepared  the  ac- 
companying two  pages  of  blueprints  in 
which  the  more  common  symbols  and 
abbreviations  have  been  defined.  In  ad- 
dition to  the  listing  of  the  symbols,  I 
have  taken  up  a  short  description  of  the 
various  parts  used  in  the  receiving  cir- 
cuits so  that  the  subject  will  be  more 
easily  followed. 

Circuit  Symbols  (Sheet  No.  1) 

1.  INDUCTANCE  (Air  Core  Type).  The 
hollow  coil  of  wire  or  other  inductance  coil  with  an 
air  core  i3  shown  by  a  continuous  scroll  or  helix 
as  in  Item  No.  1.  Its  purpose  is  to  choke  back  or 
impede  the  flow  of  radio  frequency  current  or  for 
tuning    radio    circuits    to    the    wavelength    of    the 

Blueprints  of  Conventional  Radio  Symbols  and  Typical  Crystal  Receivers  on  pages  28,  29,  30  and  31 


How  to  Understand 
All  Radio  Symbols; 
Giving  the  Crystal 
Its  Merited  Attention 


transmitting  station.  The  abbreviation  is  the 
letter  (L)  and  its  magnitude  is  generally  expressed 
in  millihenries,  or  by  the  number  of  turns  of  wire. 

2.  IRON  CORE  CHOKE.  This  consists  of  a 
great  many  turns  of  wire  wound  around  a  core  of 
soft  steel  wire  or  thin  steel  sheets  called  "lamina- 
tions." It  is  used  when  a  greater  retardation  must 
be  had  than  is  convenient  with  an  air  core  choke, 
and  can  choke  back  audio  as  well  as  radio  frequency 
currents.     Values  in  henries  or  millihenries. 

3.  TRANSFORMER-COUPLER  (Air  Core 
Type).  This  transformer  for  radio  frequency 
currents  consists  of  two  coils  of  wire  called  respec- 
tively the  PRIMARY  (PRI.),  and  the  SECON- 
DARY (SEC.)  coils.  Radio  frequency  currents 
passing  through  the  primary  induce  similar  cur- 
rents in  the  secondary  coil,  thus  affording  a  means 
of  "coupling"  two  circuits  together  magnetically. 
In  our  diagrams  the  primary  coil  (PRI)  is  shown 
with  fewer  turns  than  the  secondary  and  is  shown 
on  the  end  opposite  to  the  grid  connection  (G). 
The  other  connections  are  the  filament  (F),  the 
plate  connection  (P),  the  positive  "B"  battery 
connection  (B)  and  the  neutral  tap  (N)  used  for 
certain  neutralized  circuits.  The  abbreviation  is 
(RFT),  and  it  may  be  tuned  or  untuned,  the 
former   by   a  variable  condenser. 

4.  VARIOMETER.  This  is  a  form  of  variable 
inductance  used  in  place  of  the  air  core  choke,  and 
consists  of  a  movable  member  (The  Rotor)  which 
turns  inside  of  a  stationary  coil  called  the  "Stator." 
The  abbreviation  is  (VAR).  By  this  means  the 
inductive  or  choke  effect  can  be  varied  through  a 
wide  range  without  condensers  and  the  device  is 
frequently  used  for  tuning  a  circuit  inductively.  It 
may  be  tapped  at  the  mid-point  as  shown  at  (Q). 

5.  ANTENNA-GROUND-ARRESTOR.  At 
the  right  is  shown  the  symbol  for  the  antenna  or 
aerial,  abbreviation  (ANT).  In  the  center  is  the 
symbol  for  a  ground  connection  (GND),  and  at 
the  right  is  the  convention  for  a  lightning  arrestor 
(LA). 

6.  OUTPUT  -  PHONES  -  SPEAKER.  The 
symbol  for  the  headset  or  phones  is  shown  at  the 


left,  which  may  indicate  the  output  of  any  radio 
receiving  circuit.  Abbreviation  (PH).  The  polari- 
ty may  be  marked  by  (+)  or  minus  as  shown, 
or  this  may  be  omitted  at  will.  The  positive  con- 
nection of  the  phone  cords  is  colored  red  and  this 
red  strand  should  be  connected  to  the  (  +)  connec- 
tion of  the  circuit.  At  the  right  is  the  symbol  for 
the  horn  or  loud  speaker  which  can  also  be  marked 
with  the  polarity. 

7.  CONDENSERS.  A  "fixed"  condenser  con- 
sists of  alternate  sheets  of  tinfoil  and  paper  or  mica 
compressed  into  a  compact  pile,  and  adds 
"capacity"  to  the  circuit,  an  effect  opposite  to 
that  of  an  inductance  coil.  The  symbol  for  a  fixed 
condenser  is  at  the  left  where  the  abbreviation  is 
shown  as  (K)  and  where  the  capacity  in  micro- 
farads is  also  added  where  advisable.  A  VARI- 
ABLE CONDENSER  used  for  tuning  inductances 

i  s  shown  at  the  right,  where  the  rotor  plates  are 
i  ndicated  by  the  curved  line  and  the  stationary  or 
stator  plates  are  shown  by  the  short  straight  line. 
The  Stator  (Straight  line)  should  go  to  the  grid  of  a 
tube,  while  the  rotor  is  connected  to  the  ground 
side  or  ( — A)  side  of  the  circuit.  This  condenser 
is  also  rated  in  microfarads  (m.  f.). 

8.  RESISTANCES— RHEOSTATS.  A  fixed 
or  unvarying  resistance  is  shown  by  the  zig-zag 
line  which  distinguishes  it  from  an  inductance.  For 
low  resistances  used  for  controlling  the  filaments  of 
the  tubes,  its  magnitude  is  given  in  terms  of  ohms. 
For  very  high  resistances,  as  used  for  grid  leaks, 
the  resistance  is  given  in  terms  of  MEGOHMS, 
abbreviated    (MEG). 

A  RHEOSTAT  or  variable  resistance  is  shown 
at  the  right  and  is  usually  employed  for  controlling 
the  filament  current  of  tubes.  The  letter  (R)  is  used 
for  a  rheostat,  or  resistance. 

9.  BATTERIES.  An  "A"  or  filament  battery 
or  a  "C"  battery  is  shown  by  the  symbol  at  the  left 
which  consists  of  alternate  short  heavy  lines  and 
longer  light  lines.  The  short  heavy  lines  indicate 
the  negative  (—  )  plates  while  the  long  lines  are  the 
positive  plates  (  +).  Each  pair  of  these  lines  rep- 
resents one  cell,  and  it  is  the  best  practice  to  mark 
the  voltage  below  it  as  at  (6v.)  and  the  letter  (A), 
(B)  or  (C)  above  it  to  designate  the  type  of  battery. 
A  "B"  battery  is  at  the  right  where  the  dotted  line 
indicates  a  number  of  omitted  cells,  there  being 
too  many  cells  in  a  "B"  battery  to  draw  them  com- 
plete. When  the  battery  is  tapped  at  some  low 
voltage,  as  at  (+22),  the  voltage  of  the  tap  is 
marked  in  this  way. 

10.  PONTIOMETETER.  This  is  a  device  which 
looks  much  like  a  rheostat  used  for  the  accurate 
control  of  voltages,  generally  the  biasing  voltages 
applied  to  the  grid  of  a  vacuum  tube.  It  consists 
of  a  fixed  resistance  of  from  200  to  400  ohms  con- 
nected across  the  battery  and  a  sliding  contact 
which  taps  off  the  drop  of  potential  at  any  point  of 
the    resistance.      The    polarity   of  the   slider   also 


3E3E 


El  IDE 


SEE 


E3SC 


3  HE 


BEE 


3E3E 


UP  AND  AT  'EM! 

Perhaps  some  of  the  Dial  Twisters  and  readers  of  the  Pickups  and 
Hookups  Section  have  strayed  over  into  these  blueprint  pastures  in 
search  of  choice  morsels  of  radio  information. 

Here's  one  morsel  all  of  our  readers  should  seek: 

On  the  page  facing  the  Pickup  and  Hookup  Section,  you  will  see 
notice  of  a  monthly  subscription  contest.  For  the  month  of  August 
prizes  are  to  be  awarded  for  the  reader  who  sends  in  the  largest  number 
of  paid-up  subscriptions  to  your  favorite  journal,  RADIO  AGE. 

We  could  tell  you  a  lot  more,  but  space  is  limited.  Read  page  18  and 
then  go  after  new  radio  recruits. 


SHE 


3HE 


SHE 


3BE 


3EE 


3QE 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


25 


varies  with  its  position,  becoming  negative  at  one 
end  and  positive  at  the  other. 

11.  THREE  ELEMENT  VACUUM  TUBES. 
The  three  eiements  of  a  vacuum  tube  are  the 
filament  (F),  the  grid  (G)  and  the  plate  (P),  al- 
though these  parts  need  not  be  marked  as  shown. 
A  "hard"  amplifying  tube  is  indicated  by  a  single 
heavy  circle  drawn  around  the  elements  and  as  a 
hard  tube  is  much  used  at  present  for  a  detector  as 
well  as  for  an  amplifier.  When  a  soft  detector  tube 
must  be  used,  two  circles  are  used,  as  at  the  right. 
The  word  amplifier  is  abbreviated  (AMPL)  and 
detector  by  (DET). 

12.  TWO  AND  FOUR  ELEMENT  TUEES.  A 
two  element  tube  or  Fleming  valve  is  indicated  at 
the  right  and  has  the  filament  and  plate  but  no  grid. 
This  is  most  generally  used  as  a  rectifier  for  charg- 
ing storage  batteries  from  alternating  current,  but 
is  also  used  as  a  detector.  The  four  element  tube 
at  the  right  has  two  grids. 

13.  GRID  CONDENSER  AND  LEAK.  This 
symbol  used  with  detector  tubes  is  simply  a  combi- 
nation of  the  symbol  of  a  condenser  and  that  of  a 
resistance  (The  leak).  The  leak  abbreviation  is 
(GL)  and  the  grid  condenser  is  (GC).  If  either  of 
these  items  is  variable,  then  this  fact  is  indicated  by 
drawing  a  slanting  arrow  across  it  as  at  the  right. 

14.  CRYSTAL  DETECTOR.  A  crystal  detec- 
tor is  indicated  by  an  arrow  head  for  the  cat- 
whisker  and  a  small  block  for  the  crystal. 
Abbreviation  is  (CD). 

15.  AUDIO  (IRON  CORE)  TRANSFORMER. 
An  iron  core  transformer,  commonly  known  as  an 
audio  frequency  transformer,  is  used  for  increasing 
the  voltages  of  currents  approximating  voice  fre- 
quencies or  audible  frequencies.  It  consists  of  a 
primary  winding  (PRI)  and  a  secondary  winding 
(SEC)  with  a  few  parallel  lines  drawn  between  the 
coils  to  indicate  the  iron  core.  The  four  connec- 
tions are  marked  as  follows:  (G)  for  grid,  (P)  fcr 
plate,  (F)  for  filament  and  (B)  for  "B"  battery 
connections.  These  apply  to  vacuum  tube  connec- 
tions with  which  the  transformer  is  most  commonly 
used.  Iron  core  transformers  of  a  special  type  are 
also  sometimes  used  on  radio  frequencies,  but  when 
this  is  the  case  the  fact  will  be  particularly  noted  on 
the  drawing.     Abbr.  is  (AFT). 

16.  WIRING  AND  CONNECTIONS.  In 
general,  wiring  is  indicated  by  very  heavy  lines, 
and  curved  by  an  arc  where  a  turn  is  made.  Where 
two  wires  connect,  a  small  OPEN  circle  is  used  to 
mark  the  connection  as  at  (a).  Where  one  wire 
crosses  over  another,  the  crows-over  is  shown  as  at 
(b).  Connection  posts  or  terminals  for  batteries, 
etc.,  are  shown  by  a  circle  with  a  heavy  black  dot 
inside,  as  shown  in  a  horizontal  row.  The  letters 
indicating  the  "A",  "B",  and  "C"  batteries  are 
marked  at  the  terminals,  together  with  their 
polarities.  In  the  case  of  the  "B"  battery  connec- 
tions the  various  taps  are  marked  by  the  voltages 
as  at  (+22),  (+45)  and  (+90),  but  the  letter  "B" 
is  not  used. 

17.  TAP  SWITCHES.  Tap  switches  used  for 
cutting  out  active  turns  in  a  coil  should  be  con- 
nected so  that  the  contact  points  go  to  the  grid  or 
aerial  side  of  the  circuit  with  the  hinge  connected 
to  ground  or  on  the  far  side  from  the  grid  connec- 
tion to  prevent  body  capacity  effect. 

18.  INSTRUMENTS.  Measuring  instruments 
such  as  the  voltmeter  (VM),  the  ammeter  (AM)  or 
the  hot  wire  ammeter  (HWA)  are  shown  in  circles. 
The  polarity  should  be  marked,  and  also  the  range 
of  volts  or  amperes  at  at  (0 — 10)  and  (0 — 5). 

19.  JACKS.  Jacks  are  specially  arranged  con- 
tacts used  for  making  temporary  connections  by 
means  of  plugs  and  may  be  of  many  types.  At  the 
left  is  shown  the  single  circuit  jack  (J2)  generally 
used  for  the  last  stage  connection  and  at  the  left 
is  a  two  circuit  jack  (Jl)  used  for  plugging  in 
between  stages.  These  are  by  far  the  most  common 
types. 

20.  SWITCHES.  Different  types  of  battery 
switches  are  shown,  the  left  symbol  being  for 
symbolic  diagrams  while  the  second  from  the  left  is 
used  frequently  on  picture  diagrams.  The  switch 
at  the  right  is  a  double  pole  knife  switch  used  for 
heavy  currents. 


Sample  Symbolic  Drawings 

ON  SHEET  No.  2  we  show  four  repre- 
sentative circuit  drawings  which 
include  most  of  the  symbols  tabulated. 
Each  symbol  is  lettered  with  the  standard 
abbreviation  so  that  it  will  not  be  difficult 
to  trace  out  the  relation  between  the 
parts  in  the  table  and  the  corresponding 
parts   in   the   diagram. 

A  simple  crystal  detector  set,  tuned  by 
the  variometer  (VAR)  is  shown  in  Fig. 
21.  Here  we  have  the  symbols  for  the 
variometer,  crystal,  aerial,  ground, 
phones  and  two  fixed  condensers.  Note 
that  when  two  condensors  are  shown 
that  they  are  numbered  as  at  (Kl)  and 
(K2).  In  Fig  22  we  have  another  single 
circuit  crystal  set  tuned  by  a  simple 
tapped   inductance    (L),   the   tap   switch 


(SW)  being  used  to  vary  the  number  of 
turns  in  circuit. 

In  Fig.  23  is  a  regenerative  circuit  with 
one  stage  of  audio  frequency  amplifica- 
tion, a  type  of  circuit,  very  commonly 
met  with.  The  detector  tube  (Tl)  is  a 
soft  tube,  while  the  amplifier  tube  (T2) 
is  a  hard  tube,  as  will  be  seen  from  the 
circles.  A  coupler  is  used  for  tuning, 
having  the  primary  coil  (LI)  and  the 
secondary  coil  (L2),  this  being  used 
sometimes  instead  of  the  abbreviations 
"PRI"  and  "SEC."  The  secondary  is 
tuned  by  the  variable  condensor  (Kl). 
For  regeneration  we  have  the  tickler  coil 
(TIC)  placed  directly  above  the  second- 
ary coil  (L2)  and  connected  with  it  by- 
means  of  an  arrow.  The  arrow  in  this 
case  indicates  that  the  two  coils  are 
inductively  coupled  by  a  variable  rela- 
tion; that  is,  that  the'position  of  (TIC) 
can  be  varied  in  respect  to  (L2).  The 
grid  condensor  (GC)  and  the  grid  leak 
(GL)  are  shown  connected  to  the  grid 
of  the  tube. 

Current  for  lighting  the  tube  fila- 
ments is  supplied  by  the  six  volt  "A" 
battery  which  is  connected  so  that  the 
negative  pole  goes  to  the  detector  rheo- 
stat (Rl).  The  negative  pole  of  the 
"A"  battery  connects  with  the  negative 
pole  of  the  "B"  battery,  and  the  latter 
is  tapped  at  the  (  +  22)  volt  point  for  the 
detector  current.  The  total  voltage  of 
the  "B"  battery  at  (+90)  goes  to  the 
last  stage  jack  (J2).  A  two  circuit  jack 
(Jl)  permits  us  to  plug  in  on  the  detec- 
tor tube  alone  without  amplification,  or 
without  lighting  the  amplifier  tube 
(T2).  Plugged  in  on  (J2)  we  get  the 
amplified  or  intensified  current  for  the 
operation  of  a  loud  speaker. 

An  iron  core  audio  frequency  trans- 
former (AFT)  transfers  the  plate  energy 
of  the  detector  tube  (Tl)  to  the  amplifier 
tube  (T2),  and  it  will  be  noted  that  the 
terminals  of  the  transformer  are  marked 
in  accordance  with  the  points  that  they 
connect.  Thus  (G)  goes  to  the  grid  of 
(T2),  connection  (P)  goes  to  the  plate  of 
tube  (Tl),  connection  (B)  goes  to  the 
(+22)  volt  tap  of  the  "B"  battery,  and 
connection  (F)  goes  to  the  ( — A)  through 
the  "C"  battery.  A  fixed  condenser  (K) 
is  shunted  across  the  secondary.  A  4.5 
volt  "C"  battery  is  used  for  biasing  the 
grid  of  the  tube  (T2)  and  the  negative 
pole  ( — )  is  connected  to  (F)  of  the  trans- 
former so  that  the  current  gets  to  the 
grid  of  the  tube  through  the  windings. 
Tube  (T2)  is  controlled  by  rheostat 
(R2). 

Fig.  2-1  is  a  typical  reflex  circuit  with 
the  radio  frequency  transformer  (RFT) 
and  the  audio  frequency  transformer 
(AFT),  the  former  being  tuned  by  the 
variable  condenser  (K2).  A  coupler  is 
provided  with  the  primary  (LI)  and 
secondary  (L2)  by  which  the  set  is  tuned 
to  wavelength.  The  grid  bias  on  the 
tube  is  varied  by  the  potentiometer  (PO). 
The  rest  of  the  parts  have  been  explained 
before. 

Crystal  Detector  Sets 

TO  ME,  the  crystal  set  has  always 
seemed  the  most  wonderful  of  all 
radio  receivers,  for  with  this  device 
we  employ  the  feeble  energy  of  the  radio 
waves  alone  to  vibrate  the  diaphragms 
of  the  phones  without  aid  or  reinforce- 
ment from  local  sources  of  energy.  After 
traveling  fifty  miles  or  so,  there  is  still 
sufficient  energy  left  in  the  waves  to 
move  a  relatively  stiff  piece  of  metal  and 
to  produce  the  audible  air  vibrations 
known  as  sound.  Further,  it  is  an  exhi- 
bition of  the  remarkable  sensitivity  of 
the     modern     headset     which     produces 


understandable  signals  on  so  small  an 
amount  of  current  that  it  can  be  esti- 
mated in  millionths  of  an  ampere;  and 
yet,  with  all  of  this  delicacy,  the  appara- 
tus is  perfectly  simple  and  so  rugged 
that  it  can  withstand  a  considerable 
amount  of  abuse  at  the  hands  of  the 
listener. 

To  most  of  our  readers  who  have  had 
experience  only  with  the  cheap  and  simple 
single-slide,  single-circuit  crystal  detec- 
tor sets  sold  on  the  open  market,  the 
crystal  detector  is  considered  only  in  the 
light  of  a  toy  having  only  a  very  limited 
use  in  reception.  This,  however,  is  not 
the  case,  for  with  proper  attention  to  the 
details  of  construction  and  with  as  much 
care  taken  with  the  tuning  units  as  we 
pay  to  the  construction  of  a  tube  set,  the 
performance  can  be  greatly  improved  in 
regard  to  distance  range  and  signal 
strength.  If  we  constructed  our  tube 
sets  with  the  same  lack  of  care  and  with 
the  same  primitive  tuning  systems  that 
are  used  on  commercial  crystal  sets,  we 
would  not  get  very  much  better  perform- 
ance. Single-slider,  single-circuit  tuners 
are  not  conducive  of  good  results  with 
either  the  crystal  or  tube  detector,  for 
they  cannot  be  tuned  accurately  in  re- 
sonance with  the  incoming  waves,  and 
there  is  always  a  considerable  loss  taking 
place  that  limits  the  distance  and 
volume. 

The  Crystal  Detector  Circuit 

OUR  primitive  crystal  detector  circuit 
consists  of  three  principal  units: 
(1)  The  tuning  unit,  by  which  it  is 
brought  into  resonance  with  the  incoming 
waves,  (2)  The  crystal  detector  employed 
for  rectifying  the  radio  frequency  im- 
pulses for  the  development  of  the  audio 
waves,  and  (3)  The  audio  output  mechan- 
ism which  converts  the  audio  frequency 
electrical  waves  into  mechanical  sound 
vibrations  (Phones).  All  three  elements 
must  be  as  perfect  as  possible  if  we  are  to 
extract  the  maximum  output  in  the  form 
of  sound,  for  the  incoming  energy  is 
exceedingly  feeble  and  must  be  carefully 
utilized  with  the  least  possible  loss. 
This  means  sharp  tuning,  a  crystal  hav- 
ing excellent  rectifying  qualities  and  an 
exceedingly  sensitive  pair  of  phones, 
none  of  which  are  in  evidence  in  the  usual 
§2.00  crystal  detector  set.  In  reviewing 
the  requirements,  we  must  also  remember 
to  include  an  efficient  antenna  into  the 
assembly,  which  should  have  greater 
length  and  capacity  than  the  antenna 
commonly  used  with  tube  sets.  The 
latter  item  is  generally  neglected  in  the 
installation  of  a  crystal  set,  with  the 
result  that  very  little  volume  or  distance 
is  had.  Conservation  of  energy  is  a  prime 
requisite. 

It  is  here  that  the  low-loss  coil  and  the 
low-loss  condenser  hold  forth  with 
particular  advantage;  spiderweb,  honey- 
comb or  barrel-wound  coils  being  of 
great  advantage  in  the  construction  of 
such  a  set.  The  phones  should  prefer- 
ably be  of  the  mica  diaphragm  class  or 
with  very  thin  flexible  metal  diaphragms 
so  that  the  slightest  current  in  the  coils 
will  give  a  maximum  vibration.  When 
we  look  at  the  cheap  phones  ordinarily 
supplied  with  crystal  sets,  with  their 
thick  cast-iron  diaphragms  and  their 
weak  magnets,  it  is  no  wonder  that 
reception  is  limited  to  10  or  15  miles. 
This  would  be  almost  the  case  with  a 
tube  set  if  it  were  supplied  with  the  same 
sort  of  phones.  The  feeble  impulses 
received  demand  the  most  sensitive  and 
efficient  equipment  that  we  can  supply 
if  the  crystal  set  is  to  be  more  than  a 
mere  toy  for  children's  use. 

Please   don't   infer   that    I    am   recom- 


26 


RADIO  AGE  for  August.  1925 


The  Magazine  of  the  Hour 


mending  the  crystal  set  as  a  substitute 
for  the  tube  set,  for  I  am  not.  I  am 
simply  bringing  to  your  attention  the 
fact  that  the  crystal  set  performance  can 
be  wonderfully  improved  by  a  little  care 
in  the  construction  and  that  it  is  a  most 
desirable  proposition  for  local  reception 
where  we  do  not  wish  to  go  to  the  trouble 
of  installing  batteries  and  similar  com- 
plications. The  crystal  set  has  a  field 
all  its  own  and  is  almost  indispensable 
for  certain  purposes,  and  for  this  reason 
I  believe  that  more  attention  should  be 
paid  to  the  development  of  its  perform- 
ance rather  than  to  cutting  down  on  the 
expense  of  construction,  as  has  been  done 
heretofore.  You  cannot  get  long  distance 
consistently,  nor  can  you  get  full  loud 
speaker  volume  of  the  crystal  alone,  but 
you  can  get  locals  with  good  volume, 
clear  and  sweet,  without  the  fuss  attend- 
ing the  operation  of  a  tube  receiver. 

When  loud  speaker  volume  is  required 
on  local,  with  particular  attention  to 
quality,  we  can  add  one  or  more  stages 
of  audio  frequency  amplification  to  the 
detector.  Of  course,  we  are  now  getting 
back  to  vacuum  tube  complications  and 
batteries,  but  with  very  simple  layouts 
we  can  obtain  wonderful  tone  values  on 
the  loud  speaker  and  a  somewhat  in- 
creased distance.  Just  as  an  experi- 
ment, it  is  very  interesting  to  add  resist- 
ance coupled  stages  to  a  crystal  detector 
to  discover  what  real  tone  purity  is  like. 
The  natural  tone  and  life-like  quality- 
will  be  a  revelation  to  you,  and  if  you 
live  within  25  miles  or  so  of  a  broad- 
casting station,  I  am  sure  that  you  will 
keep  this  circuit  hooked  up  permanently. 

Future  of  the  Crystal  Set 

CONSIDERING  the  many  5,000  watt 
broadcasting  stations  now  under 
construction,  and  the  increasing  practice 
of  re-broadcasting,  it  is  certain  that  the 
crystal  detector  receiver  will  find  a  more 
extended  use  than  has  been  the  case  in 
the  past.  Increased  power  at  the  stations 
and  the  relaying  of  these  stations  at  close 
intervals  over  the  country  will  mean  that 
the  crystal  will  take  on  a  new  life.  At 
least  ten  telephone  companies  have 
adopted  local  re-broadcasting  systems  as 
an  additional  service  to  their  subscribers, 
and  I  do  not  believe  that  the  telephone 
companies  will  be  the  only  people  to 
engage  in  this  work.  If  the  network  of 
re-broadcasting  stations  is  fully  developed 
the  use  of  the  crystal  set  will  be  practical 
in  almost  any  part  of  the  United  States. 
One  re-broadcast  station  equipped 
with  a  good  receiving  set  and  a  trans- 
mitter of  moderate  power  will  easily 
cover  a  radius  of  25  miles  and  will 
efficiently  serve  crystal  detectors  in  this 
50-mile  circle.  The  expense  of  main- 
taining such  a  station  is  comparatively 
small  and  can  be  borne  by  the  local 
Granges  or  community  associations  with 
a  great  saving  to  their  members.  The 
station  receives  the  voice  and  music 
from  distant  stations  and  then  broad- 
casts these  signals  through  simple  appa- 
ratus to  local  listeners,  thus  avoiding  the 
expense  and  trouble  of  arranging  pro- 
grams. So  far,  this  arrangement  has 
increased  the  total  number  of  listeners 
tremendously  without  appreciably  affect- 
ing the  sale  of  tube  sets.  On  the  contrary, 
one  re-broadcasting  station  states  that 
the  interest  aroused  in  radio  via  crystal 
sets  has  greatly  increased  the  sale  of  tube 
sets  in  its  territory,  and  that  a  great 
proportion  of  the  listeners  now  have 
both  crystal  and  tube  sets  in  their 
homes.  Tiring  of  the  local  re-broadcasts, 
and  desiring  different  programs,  they 
turn  to  their  tube  sets  and  tune  in  the 
distant  stations  for  themselves. 


While  the  complete  theory  of  contact 
rectification  is  not  yet  well  understood, 
I  will  explain  the  functioning  and  purpose 
of  the  crystal  in  a  general  way  so  that 
the  beginner  can  at  least  get  a  working 
knowledge  of  its  properties  when  in- 
stalled in  the  receiving  set.  Mechani- 
cally it  is  very  simple,  consisting  of  a 
small  piece  of  mineral  called  the  crystal, 
and  a  thin  wire  making  light  contact 
with  the  crystal  at  a  sensitive  spot.  In 
some  cases,  contact  is  had  between  twro 
crystals  instead  of  between  the  wire 
and  crystal,  but  in  any  event  the  radio 
frequency  current  must  pass  through  a 
high  resistance  contact  of  some  sort 
before  passing  through  the  phones,  so 
that  the  audio  or  "hearable"  portion  of 
the  incoming  waves  can  be  developed. 

Owing  to  the  rapidity  with  which  the 
radio  wave  oscillates  back  and  forth,  the 
diagrams  of  the  phones  cannot  follow  the 
radio   frequency  currents  in  the  receiver 


A  ROUND-UP  OF 
HOOK-UPS 

Will  Rogers  would  probably  call 
this  August  number  a  "Radio 
Rodeo"  but  we  have  named  it  the 
De  Luxe  Edition. 

Having  seen  and  burrowed  in  its 
alternate  reading  and  blueprint 
pages,  you  will  no  doubt  want  to 
send  a  copy  to  one  of  your  friends 
who  so  far  has  resisted  the  lure  of 
radio. 

A  very  simple  matter!  Get  an 
extra  copy  from  your  newsdealer 
and  pass  it  on  to  your  friend. 
Then  watch  the  fun. 

OR 

If  you  must,  take  his  $2.50  for  a 
year's  subscription  to  the  Magazine 
of  the  Hour. 


directly  and  nothing  will  be  heard  in  the 
phones  if  some  sort  of  rectifier  or  "de- 
tector" is  not  inserted  into  the  circuit. 
These  waves  are  "alternating,"  that  is, 
they  flow  first  in  one  direction  and  then 
in  the  other,  and  before  we  hear  the  sig- 
nals these  waves  must  be  made  "uni- 
directional" so  that  they  will  flow  in  one 
direction  through  the  phones  but  with 
an  intensity  that  varies  according  to  the 
sounds  sent  out  by  the  broadcasting 
station.  The  crystal  detector  with  its 
contacting  "catwhisker"  wire  acts  as 
such  a  rectifier  and  permits  the  passage 
of  only  one  set  of  waves  that  are  flowing 
in  the  same  direction. 

With  the  radio  frequency  current  rec- 
tified, the  "audio  frequency"  waves  are 
developed  so  that  the  diaphragms  of  the 
phones  follow  the  slower  voice  frequency 
pulsations,  thus  producing  sound.  Our 
station  waves  therefore  consist  of  two 
components,  the  high  radio  frequency 
carrier  waves  oscillating  at  the  rate  of 
about  1,000,000  vibrations  per  second, 
and  the  audio  frequency  waves  impressed 
on  them  that  will  range  from  a  few  hun- 
dred to  an  upper  limit  of  about  15,000 
vibrations  per  second.  These  latter 
waves  are  produced  by  varying  the  in- 
tensity of  the  radio  waves  by  "modula- 
tion," and  are  not  actually  an  indepen- 
dent series. 

There  are  a  great  number  of  minerals 
that  will  act  as  detectors  to  some  extent, 
but  only  a  few  that  are  effective  enough 
to  be  used  in  the  practical  crystal   set. 


Galena,  silicon,  carborundum,  cerusite, 
pyrites,  perikon,  radiocite,  and  hecite  are 
among  the  most  commonly  used  simple 
minerals,  and  in  addition  to  these  are  the 
numerous  synthetic  crystals  that  bear  a 
multitude  of  trade  names.  A  good  galena 
crystal  is  probably  one  of  the  most  sensi- 
tive crystals,  but  it  is  not  stable  and  must 
be  readjusted  frequently.  Silicon  and 
carborundum  do  not  require  so  frequent 
adjustment  and  are  quite  sensitive  if 
carefully  selected  and  mounted.  The 
synthetic  crystals  are  in  most  cases  stable 
and  sensitive,  and  have  the  advantage  ot 
having  a  greater  effective  area  or  more 
"hot  spots"  than  the  natural  crystals,  so 
that  it  is  not  so  difficult  to  adjust  them. 

For  the  catswhisker  wire,  we  require 
a  metal  that  will  not  corrode  under 
ordinary  atmospheric  conditions  and  one 
that  will  maintain  a  bright  metallic  con- 
tact area  at  the  point  where  it  rests  on  the 
crystal.  A  copper  wire  will  work  well 
with  most  crystals,  but  a  silver  or  gold 
wire  is  better,  as  it  does  not  corrode  or 
get  dull  as  rapidly.  With  the  exception 
of  the  carborundum  crystal,  the  cat- 
whisker  wire  should  make  very  light 
contact  with  the  crystal,  working  best 
when  only  just  barely  touching  the  sur- 
face. With  the  carborundum  detector  a 
very  heavy  pressure  is  required,  which 
in  itself  is  one  reason  for  the  stability  of 
the  carborundum,  as  the  heavy  pressure 
prevents  the  displacement  of  the  contact 
when  subjected  to  vibration. 

There  has  been  a  great  deal  of  argu- 
ment for  and  against  the  fixed  crystal 
detector  with  the  immovable  catwhisker, 
but  I  believe  that  the  fixed  detector  will 
prove  best  in  the  long  run  for  the  begin- 
ner, at  least,  as  it  avoids  the  necessity  of 
constant  readjustment  and  the  detuning 
effect  when  these  adjustments  are  made. 
It  will  perhaps  be  of  interest  to  know  that 
the  crystal  has  a  great  deal  of  effect  in 
the  tuning  of  the  circuit  and  very  often 
we  can  tune  a  station  in  and  out  by  means 
of  the  crystal  adjustment  alone.  For  the 
experienced  crystal  set  operator,  the 
adjustable  crystal  is  therefore  often  an 
advantage,  as  it  is  an  aid  to  selectivity 
and  tuning,  particularly  where  there  are 
many  strong  local  stations  and  other 
interferences. 

It  is  a  good  plan  to  get  a  number  of 
crystals  and  then  select  the  best  crystal 
by  actual  test.  There  is  a  great  deal  of 
variation  among  crystals  even  of  the  same 
make,  and  the  only  way  that  you  can  be 
assured  of  the  maximum  results  is  to 
select  the  best  crystal  from  a  number  of 
samples. 

The  Hook-Up  or  Circuit 

THERE  are  about  a  thousand  different 
crystal  detector  hook-ups  from  which 
to  make  a  choice,  and  all  of  them  have 
their  adherents,  who  believe  that  they 
have  the  only  circuit  worth  using.  Some 
employ  variometers  for  tuning  induct- 
ances, others  use  spiderweb  coils,  vario- 
couplers,  honeycomb  coils  and  straight 
solenoid  coils  in  all  sort  of  combinations, 
but  as  a  matter  of  fact,  a  close  examina- 
tion will  show  that  most  of  these  circuits 
can  be  boiled  down  to  six  distinct  classes. 
The  type  of  inductance  does  not  change 
the  characteristics  of  a  circuit  as  a  circuit; 
it  simply  adds  or  detracts  from  its  effi- 
ciency by  the  sharpness  of  its  tuning 
properties  and  the  losses  occuring  within 
the  coil.  A  variometer  may  show  better 
results  than  a  simple  tuning  coil,  simply 
for  the  reason  that  it  can  be  more  closely 
adjusted  to  wavelength  than  the  coil — 
not  because  it  is  a  variometer.  An  in- 
ductance is  an  inductance  no  matter  what 
form  it  mav  be  used. 


RADIO  AGE  for  August,  192: 


The  Magazine  of  the  Hour 


27 


Fig.  1  shows  the  six  basic  circuits  with 
their  relative  audibility  value,  as  de- 
termined by  the  U.  S.  Bureau  of  Stan- 
dards. The  relative  signal  strengths  are 
given  in  terms  of  percentages,  and  it  will 
be  seen  that  the  hook-up  has  a  great  deal 
to  do  with  the  reception,  varying  as  it 
does  from  10  per  cent  to  85  per  cent. 
These  diagrams  refer  only  to  the  detector 
circuit  itself  and  do  not  consider  the 
various  methods  of  coupling  or  connect- 
ing the  circuit  to  the  aerial  and  ground. 
A  variable  condenser  is  used  for  tuning 
a  fixed  inductance  in  all  cases. 

Diagram  A 

Diagram  (A)  shows  a  simple  form  of 
circuit  often  used,  which  contains  the 
inductance  (L),  the  variable  condenser 
(C),  the  crystal  detector  (CD)  and  the 
phones  (Ph)  all  connected  in  series.  For 
ordinary  broadcasting  wavelengths  there 
will  be  about  55  turns  of  wire  in  (L)  when 
wound  on  a  three  inch  tube,  and  the  ca- 
pacity of  the  variable  condenser  (C)  will 
be  from  0.00035  m.f.  to  0.0005  m.f.  The 
audibility  is  55  per  cent. 

Diagram  B 

In  Diagram  (B)  we  have  the  same  cir- 
cuit with  the  addition  of  the  small  fixed 
condenser  (K)  connected  across  the  cry- 
stal detector.  This  fixed  condenser  acts 
as  a  storage  capacity  for  the  waves  and 
adds  considerably  to  the  volume,  as  it 
supplies  an  additional  current  to  the 
crystal.  This  addition  has  increased  the 
audibility  from  55  per  cent  to  85  per  cent, 
the  maximum  value  determined  by  the 
Bureau. 

The  capacity  of  (K)  depends  upon  the 
nature  of  the  crystal  detector,  but  in  any 
event  the  capacity  must  be  small  to 
prevent  by-passing  much  of  the  current 
across  the  dectector.  With  some  de- 
tectors 0.00025  m.  f.  is  about  right, 
while  with  other  types  this  may  be  as 
low  as  0.0001  m.f.  or  even  less.  A  small 
three-plate  variable  condenser  will  often 
prove  of  value  in  getting  the  adjust- 
ment correctly. 

Diagram  C 

In  Diagram  (C)  we  have  the  same  cir- 
cuit as  in  Diagram  (A),  but  a  fixed  con- 
denser (K)  is  used  to  bypass  radio  fre- 
quency current  around  the  phones.  The 
average  audibility  under  all  conditions 
is  reduced  to  45  per  cent ;  hence,  this  is  not 
always  an  advisable  addition.  In  many 
makes  of  phones  there  is  a  considerable 
amount  of  distributed  capacity  in  the 
windings  of  the  magnets  and  this  fre- 
quently is  sufficient  to  properly  by-pass 
the  radio  frequency  current  around  the 
inductance  without  the  addition  of  ex- 
ternal capacity.  However,  in  case  the 
phones  have  a  high  inductive  value  with 
little  distributed  capacity,  a  by-pass  (K) 
may  be  necessary. 

Diagram  D 

Diagram  (D)  is  a  type  of  crvstal  de- 
tector circuit  often  used  on  wave-meters 
and  similar  instruments  where  very  sharp 
tuning  is  necessary.  The  audibility  is  so 
low  (10  per  cent)  that  it  is  impracticable 
for  a  receiver  and  therefore  need  not  be 
discussed  further.  Its  only  virtue  is  its 
extreme    selectivity. 

Diagram  E 

Diagram  (E)  a  second  variable  con- 
denser (C2)  is  employed  in  addition  to 
the  original  variable  condenser  (CI). 
This  sharpens  the  tuning  considerably 
and  has  a  much  greater  audibility  than 
the  circuit  in  Diagram  (D).  The  audi- 
bility is  four  times  as  great  as  with   (D) 


and  is  almost  equal  to  that  of  the  first 
diagram. 

Diagram  F 

Our  last  diagram  (F)  is  the  ultimate  in 
selectivity  but  has  a  very  low  audibility 
factor.  The  circuit  is  split  by  means  of 
the  coupler  coils  (L2)  and  (L3)  so  that 
almost  any  degree  of  selectivity  can  be 
attained  but  at  the  expense  of  a  great 
loss  in  .signal  strength.  We  can  obtain 
a  good  degree  of  selectivity  by  other 
means  and  without  so  much  loss  in  signal 
strength;  hence,  this  type  or  circuit  can  be 
neglected  for  the  time  being. 

Circuit  With  Coupler 

FOR  the  sake  of  selectivity  we  will  con- 
nect our  aerial  and  ground  to  the 
detector  circuit  by  means  of  an  aperiodic 
or  semi-aperiodic  coupler  of  the  type  so 
commonly  use  in  tube  sets.  For  the  de- 
tector circuit  we  will  adopt  the  circuit 
shown  in  Diagram  (B)  to  obtain  the 
greatest  signal  strength  and  will  depend 
entirely  upon  the  coupler  construction 
for  our  selectivity  and  tuning.  This 
combination  will  probably  give  us  the 
best  all-round  combination  for  signal 
strength  and  selectivity  and  at  the  same 
time  is  simple  to  build  and  tune. 

In  Fig.  2  we  have  the  schematic  dia- 
gram of  the  complete  circuit.  The 
coupler  consists  of  the  primary  coil  (LI) 
connected  at  one  end  to  the  aerial  and 
to  the  ground  at  the  other  end.  The  radio 
impulses  from  (LI)  are  communicated  to 
the  secondary  coil  (L2)  which  is  identical 
with  the  coil  (L)  in  Diagram  (B).  A 
variable  condenser  (CI)  is  connected 
across  the  secondary  coil  so  that  it  can  be 
tuned  to  wavelength.  The  fixed  con- 
denser (K)  connected  across  the  crystal 
detector  (CD)  serves  the  purpose  al- 
ready described.  The  phones  (Ph)  are 
in  series  with  the  crystal  detector. 

By  means  of  the  inductively  coupled 
coils  (LI)  and  (L2)  we  can  obtain  much 
better  selectivity  than  with  the  aerial  and 
ground  connected  directly  to  the  de- 
tector circuit.  The  selectivity  depends 
largely  upon  the  distance  between  these 
two  coils.  The  greater  the  distance  the 
greater  will  be  the  tuning  qualities  where 
there  are  many  strong  local  stations. 
Properly  adjusted,  it  is  possible  to  tune 
in  and  out  on  a  difference  of  five  meters 
wavelength,  but  with  comparatively  lit- 
tle loss  in  signal  strength.  With  the 
aerial  and  ground  connected  directly  to 
the  detector  circuit,  it  is  probable  that  a 
nearby  station  will  come  in  all  around 
the  dial,  no  matter  how  it  may  be  turned. 

Holds  on  Grimly 

In  regard  to  a  crystal  detector,  it  may 
be  said  that  it  is  much  more  difficult  to 
get  selectivity  with  a  crystal  than  with 
a  tube  receiver  and  that  greater  care  will 
be  required  in  the  adjustment.  The 
crystal  has  the  peculiar  property  of  hang- 
ing on  to  a  station  even  against  powerful 
controls,  and  while  it  has  not  much  dis- 
tance or  ability  on  weak  signals,  it  will  hold 
onlike'grim.death  to  fairly  strong  signals. 

Under  some  conditions  it  may  be  ad- 
visable to  connect  the  lower  part  of  the 
circuit  to  the  ground  connection  (GND) 
by  means  of  the  short  dotted  wire  (g). 
The  rotary  plates  should  also  go  to  this 
side  of  the  circuit  (ground)  as  indicated 
by  the  curved  line  at  (CI)  and  the 
stationary  plates  are  connected  directly 
to  the  crystal  detector  (CD). 

With  some  phones,  which  have  very 
little  distributed  capacity,  it  may  help 
matters  to  connect  the  fixed  condenser 
(Kl)  across  the  phones  (Ph)  as  indicated 
by  the  dotted  lines.  This  is  best  deter- 
mined by  actual  test,  after  the  set  has 


been  built  and  connected  up  to  the  aerial. 
This  may  be  a  0.001  m.f.  fixed  condenser. 

Picture  Diagram  of  Set 

A  complete  drawing  of  the  circuit  with 
all  of  the  parts  in  place  is  shown  by  Fig. 
3,  the  letters  in  this  drawing  correspond- 
ing with  similar  letters  in  the  schematic 
diagram  of  Fig.  2.  A  detail  view  of  the 
coupler  coil  is  shown  which  is  connected 
to  the  variable  tuning  condenser  (CI), 
the  latter  being  connected  directly  across 
the  secondary  coil  (L2)  of  the  tuning  in- 
ductance. The  crystal  detector  (CD)  is 
best  placed  as  shown  and  should  not 
be  mounted  on  the  front  panel  where  it  is 
likely  to  be  thrown  out  of  adjustment  by 
the  jar  of  the  hand  every  time  we  move 
the  tuning  dial. 

The  tuning  inductance  (L1-L2)  is 
wound  on  a  cardboard  tube  three  inches 
in  diameter  and  about  4  1-2  incles  long. 
The  primary  winding  consists  of  12  turns 
of  No.  24  D.C.C.  wire,  and  a  space  of 
about  1-2  inch  is  left  between  this  coil 
and  the  secondary  coil  (L2).  Starting 
coil  (L2),  we  wind  on  55  turns  of  the  same 
size  wire,  and  fasten  the  ends  of  the  coil 
securely  by  passing  them  through  holes 
punched  in  the  cardboard  tube.  For 
strong  local  stations,  it  may  be  necessary 
to  increase  the  distance  between  coils  to 
5-8  inch  or  3-4  inch  to  obtain  the  required 
selectivity,  but  this  space  should  be  no 
greater  than  actually  required  for  the 
complete  tuning  out  of  the  strongest 
station.  If  the  gap  is  much  greater  than 
this,  the  signal  strength  will  be  reduced. 
The  tentative  wire  (g)  and  the  experimen- 
tal fixed  condenser  (Kl)  are  shown  in 
dotted  lines  as  they  may  not  be  needed 
with  the  combination  of  parts  used  in 
your  set. 

The  condenser  (CI)  can  be  either  a  17 
plate  or  23  plate  variable  condenser  hav- 
ing a  capacity  of  0.00035  m.m.  to  0.0005 
m.m.,  but  the  latter  is  preferable.  If  you 
do  not  wish  to  wind  the  coil  yourself,  you 
can  use  a  neutrodyne  transformer  which 
can  be  purchased  complete  and  mounted 
on  the  back  of  the  variable  condenser. 
Such  combinations  cover  a  wavelength 
band  of  from  200  to  600  meters,  the  range 
of  the  average  broadcasting  stations. 

It  is  most  convenient  to  mount  the 
apparatus  on  a  6  in.  x  7  in.  x3-16  in.  panel 
as  shown  by  Fig.  4  with  the  tuning  dial 
(D)  appearing  on  the  front  of  the  panel 
as  shown.  The  aerial  binding  post  is  at 
ANT,  the  ground  connecting  post  at 
GND,  and  the  phone  posts  at  PH.  The 
method  of  connecting  to  the  aerial  and 
ground  is  also  shown  in  this  view,  the 
ground  being  a  connection  to  a  water  or 
steam  pipe. 

The  aerial  should  not  be  less  than  60 
feet  in  length,  and  more  than  this  is 
desirable  where  the  necessary  room  can  be 
obtained.  With  a  crystal  detector  set, 
the  more  aerial  wire  that  we  hang  up,  the 
better  will  be  our  reception,  and  any 
length  (L)  can  be  used  up  to  150  feet. 

With  two  wires  placed  side  by  side,  150 
feet  long  and  with  the  set  located  in  the 
open  country,  quite  long  distances  can  be 
covered.  However,  with  a  60  foot  aerial 
in  a  good  locality,  we  can  get  good  re- 
ception with  fair  distance,  providing  that 
the  aerial  is  not  screened  by  steel  struc- 
tures such  as  steel  factory  and  office 
buildings,  bridges,  etc. 


John  B.  Rathbun 

has  a  surprise 

in  the  August  Radio  Age 


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32  RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


A  Capacity  Feed-back  Receiver 

By  JOHN  B.  RATHBUN 


NEARLY  all  of  our  readers  are 
familiar  with  the  inductive  feed- 
back types  of  regenerative  cir- 
cuits in  which  the  plate  energy  is  re- 
turned to  the  grid  circuit  through  the 
inductive  effect  of  a  tickler  coil,  or  by 
means  of  tuning  the  plate  and  grid  into 
a  mutual  resonance  by  means  of  plate 
and  grid  variometers.  He  is  also  familiar 
with  the  direct  feedback  type  in  which 
the  plate  circuit  is  connected  directly 
with  the  aerial  as  in  the  single  circuit 
Ultra-audions    and    other    circuits. 

However,  there  is  a  third  means  of 
feedback  which  is  highly  effective,  known 
as  the  "capacitative  feedback"  by  which 
the  plate  energy  is  returned  to  the 
primary  and  controlled  through  a  varia- 
ble condenser  between  the  .  primary  in- 
ductance and  the  plate. 

As  with  the  inductive  feedbacks,  there 
are  a  great  number  of  circuit  combina- 
tions possible  with  the  capacity  feed- 
back system  and  one  has  only  to  con- 
sult an  English  radio  magazine  to  dis- 
cover this  fact.  Its  popularity  in  Eng- 
land is  undoubtedly  due  to  the  fact 
that  a  capacitative  feedback  circuit 
has  a  lesser  tendency  toward  breaking 
down  into  free  oscillations  when  the 
circuit  is  being  forced,  and  as  we  all 
know,  radiation  from  the  aerial  is 
the  Englishman's  private  pet  peeve. 
Another  factor  which  stands  in  favor  of 
the  capacitative  system  is  the  fact  that 
much  closer  control  of  regeneration  is 
possible  by  means  of  a  vernier  variable 
condenser  than  by  the  standard  tickler 
coil  arrangements,  and  tKat  the  tube 
can  be  brought  closer  to  the  spilling 
point  without  actually  causing  trouble. 

A  Sensitive  Hookup 
I"  CLAIM  no  originality  for  the  gen- 
-*-  eral  type  of  circuit  which  is  demon- 
strated in  this  article  except  in  points 
of  minor  refinements.  It  has  been 
variously  known  as  the  "Super-Reinartz," 
as  the  "Inverted  Weagant,"  and  the 
"Capacitative  LHtra-Audion"  at  various 
times.  However,  no  matter  what  its 
origin  may  have  been,  it  is  an  exceedingly 
sensitive  circuit  and  gives  great  signal 
strength  on  local.  The  circuit  is  tuned 
to  wavelength  by  means  of  a  variometer 
while  the  feedback  is  controlled  by 
means  of  a  vernier  variable  condenser. 
The  principal  improvement  introduced 
in  this  article  is  the  use  of  a  spiderweb 
type  of  variometer. 

In  Fig.  1  of  the  accompanying  blue- 
prints we  show  a  wiring  diagram  and 
plan  view  (Looking  down  on  top  of  the 
set)  which  is  for  the  use  of  our  readers 
who  are  not  familiar  with  conventional 
or  symbolical  diagrams.  In  Fig.  2  is 
the  symbolical  diagram  of  the  set  for 
the  information  of  the  advanced  readers 
who  may  wish  to  learn  how  the  circuit 
functions.     An    isometric    view  in  Fig.  3 


A  Sensitive  Circuit 
withGreaterVolume; 
Variable  Condenser 
Controls    Reaction 


shows  the  general  arrangement  on  the 
rear  of  the  panel  and  the  run  of  the 
wiring,  but  we  advise  the  reader  to  make 
the  actual  wiring  connections"  with  the 
aid  of  either  Fig.  1  or  Fig.  2  as  in  these 
views  the  wiring  is  clearer  and  easier  to 
follow.  Keep  these  blueprint  diagrams 
for  reference  and  you  will  have  no  trouble 
with  this  set. 

Looking  at  Figs.  1-2  we  see  the  tuning 
variometer  (VA)  which  is  really  a  spe- 
cially connected  vario  coupler  of  the 
spiderweb  type.  In  the  particular 
coupler  shown  a  movable  coil  or  "rotor" 
marked  (r)  is  connected  in  series  with 
the  stator  (s),  the  latter  being  the  tapped 
coil.  The  tapped  portion  (L)  of  the 
coupler  stator  is  simply  the  tapped  por- 
tion of  this  member  but  is  drawn  out 
separately  in  Fig.  2  for  emphasis  in  show- 
ing the  application  of  the  tap  switch 
(TS).  The  tap  switch  gives  closer  con- 
trol of  the  tuning  and  it  will  be  noted 
that  no  variable  condenser  is  included 
in   the   grid   circuit. 

Regeneration    Control 

AT  (CI)  we  have  the  vernier  variable 
-^*-  condenser  in  the  plate  circuit  which 
controls  the  regeneration  or  feed  back 
into  the  aerial  or  primary  circuit.  On 
tracing  out  the  hookup  we  will  see  that 
the  condenser  (CI)  is  effectively  in  series 
with  the  variometer  (VA)  and  therefore 
that  the  variometer  acts  as  an  auto- 
transformer  for  the  plate  circuit,  increas- 
ing the  potential  applied  to  the  grid  of 
the  tube.  This  is  identical  in  action 
to  the  Weagant  circuit  except  that  an 
auto-transformer  (Single  circuit  induct- 
ance) is  applied  instead  of  the  two  cir- 
cuit transformer  used  in  the  Weagant. 
Maximum  potential  is  developed  be- 
tween (CI)  and  (VA)  at  the  point  where 
the  grid  circuit  is  connected  through 
the  grid  condenser  (GC)  and  the  grid 
leak  (GL).  The  detector  tube  is  at 
(Tl)  with  its  controlling  rheostat  (Rl). 
The  use  of  a  spiderweb  inductance 
in  this  circuit  eliminates  a  great  deal 
of  the  wasteful  distributed  capacity 
which  commonly  grounds  a  large  per- 
centage of  the  aerial  current  in  single 
circuit  receivers  of  this  class.  This  is  a 
marked  advantage  over  the  layer  wound 
type  of  coupler  and  shows  up  well  in 
practice.  The  tap  points  on  the  section 
(L)  are  connected  to  the  tap  switch  (TS) 


in  the  conventional  manner,  and  the  blade 
of  the  switch  is  then  connected  to  ground. 

Variable  condenser  (CI)  should  have 
ample  capacity,  hence  should  be  a  43 
plate  or  0.001  mf  type.  The  grid  con- 
denser (GC)  is  a  mica  dielectric  type 
with  a  capacity  of  0.00025  mf  while 
the  grid  leak  (GL)  should  be  either  a 
variable  leak  or  else  a  fixed  type  with  a 
resistance  of  about  1.0  to  1.5  megohms. 
The  tube  (Tl)  can  be  any  standard 
tube  of  the  amplifier  type  such  as  the 
UV-201A  or  UV-199  type.  It  will  be 
noted  that  both  the  detector  tube  (Tl) 
and  the  audio  amplifier  tube  (T2)  are 
connected  to  the  positive  terminal  of 
the  same  "B"  battery  and  therefore 
that  both  tubes  carry  the  same  high 
plate  voltage.  The  "B"  battery  voltage 
will  range  from  45  to  90  volts,  but  the 
best  results  are  obtained  at  67.5  volts 
with  the  majority  of  tubes. 

At  the  output  of  the  detector  circuit 
we  have  the  primary  coil  (  +  B-P)  of  the 
audio  frequency  transformer  (T)  con- 
nected in  the  plate  circuit.  A  fixed 
condenser  (Kl)  is  connected  across  the 
primary  which  has  a  capacity  of  0.001 
mf.  The  secondary  coil  ( — F)  and  (G) 
is  connected  to  the  audio  amplifying 
tube  (T2)  through  the  4.5  volt  "C" 
battery  (C).  The  transformer  (AT) 
should  have  a  ratio  of  from  5-1  to  6-1 
for  the  best  combination  of  amplifica- 
tion and  clear  tone.  Lower  rations  give 
less  distortion  but  also  less  volume. 
It  should  be  particularly  noted  that  the 
( — )  negative  pole  of  the  "C"  battery 
should  go  to  the  grid  post  (G)  of  the 
amplifying  tube  socket   (T2). 

Simple   Output   Arrangement 

OIMPLE  single  circuit  jacks  (J1-J2' 
^  are  used  in  both  stages,  and  while 
this  leads  to  slightly  diminished  volume 
in  the  detector  stage,  yet  this  is  no 
practical  disadvantage  as  the  detector 
is  used  only  for  receiving  local  stations 
in  the  majority  of  cases.  The  advan- 
tage lies  in  the  simplicity  of  the  jack 
connections  and  in  the  fact  that  the 
circuit  is  not  broken  at  any  time  in 
switching  from  one  stage  to  the  other. 
There  can  be  no  open  circuits  due  to 
poor  jack  contact  nor  microphonic 
noises  set  up  as  this  point.  In  the  hands 
of  the  novice  a  two  circuit  jack  in  the 
detector  stage  very  frequently  leads  to 
trouble.  Jack  (J2)  in  the  audio  stage 
is  of  the  usual  type  and  requires  no 
further    explanation. 

The  only  special  instructions  that 
seem  necessary  for  this  circuit  are  those 
which  relate  to  the  conversion  of  a  vario- 
coupler  into  a  tapped  variometer.  One 
lead  from  the  rotor  or  movable  coil 
shown  by  (r)  in  Fig.  2  is  connected  to 
the  outermost  lead  from  the  stator 
coil     (s).       In    this    way    the    rotor    and 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


stator  are  connected  in  series  and  the 
device  now  becomes  a  variometer.  Do 
not  make  the  connection  with  the  tapped 
end  of  the  stator  coil.  Leave  the  tapped 
end  open  for  the  inductance  switch 
connection. 

Good  Distance  Work 

With  this  set,  the  writer  has  pulled 
them  in  for  very  considerable  distances 
and  with  surprising  volume.  It  has  all 
the  signal  strength  of  a  single  circuit 
receiver  combined  with  a  great  >  per- 
centage of  the  selectivity  of  the  three 
circuit  type.  It  is  not  quite  so  selective 
as  a  three  circuit  tuner,  especially  when 
two  or  three  local  stations  are  going  at 
one  time,  but  it  is  much  better  than  the 
average  single  circuit  arrangement  in 
this  respect.  One  stage  of  audio  fre- 
quency amplification  is  always  desirable 
with  any  regenerative  and  is  quite 
economical.  It  is  the  addition  of  the 
second  stage  that  leads  to  complication 
and  expense. 

One  stage  of  audio  permits  of  excellent 
loud  speaker  volume  on  stations  up  to 
100  miles  or  so  and  makes  headphone 
signals  audible  that  would  often  be 
passed  by  with  the  detector  tube  alone. 
With  UV-199-  tubes,  both  stages  can 
be  worked  off  of  three  No.  6  dry  cells 
for  a  long  time  and  with  excellent  results. 
By  biasing  the  audio  tube  (T2)  the  total 
demand  on  the  "B"  batteries  is  very 
light  and  the  smallest  size  of  cells  can 
be   used   for   long   periods. 

"B"    Battery    Current 

WHILE  the  amplification  is  slightly 
better  with  90  volts  of  "B"  battery 
on  the  plate  yet  67.5  volts  gives  nearly 
the  same  volume  with  a  much  smaller 
consumption  of  "B"  battery  current 
and  witn  less  tendency  toward  whistling. 
With  45  volts  on  the  plate  the  tone  is 
probably  purer  but  the  amplification  is 
very  much  reduced.  If  only  45  volts 
are  used,  then  the  "C"  battery  shoulrl 
be  reduced  to  a  two  cell,  three  volt 
type  in  place  of  the  three  cell  4.5  volt 
battery  used  for  67.5  to  90  volts. 

Ftom  40  to  60  feet  of  outdoor  flat 
top  aerial  will  give  very  good  results. 
If  the  aerial  is  made  longer  than  this 
there  will  be  trouble  in  maintaining  the 
required  selectivity  although  a  longer 
aerial  may  give  a  slightly  greater  range. 
The  great  trouble  with  the  majority  of 
listeners  lies  in  the  fact  that  they  try 
to  hang  up  too  much  wire  in  their  aerial 
circuit  and  in  so  doing  increase  the 
interference  and  disturbing  noises  that 
may  originate  in  the  neighborhood. 
A  single  wire  is  better  than  two  wires  in 
parallel. 

A  7"xl4"  panel  can  be  made  to  accom- 
modate this  apparatus  as  laid  out  in 
the  drawings  without  much  squeezing. 
If  it  is  likely  that  a  second  stage  of 
audio  will  be  added  in  the  future  then  a 
panel  7"xl8"  should  be  used.  Bakelite 
or  hard  rubber  are  the  best  materials 
for  the  panel,  and  while  the  baseboard 
•s  usually  made  of  wood  this  can  also 
be   made   of   hard   rubber   or   bakelite. 


In  the  old  days  when  Armstrong  was 
publishing  his  original  means  of  producing 
regeneration  and  oscillation  by  means 
of  an  inductance  in  series  with  the  B 
battery  and  phones,  which  was  induc- 
tively coupled  to  the  grid  circuit,  Weag- 
ant  came  along  with  another  means  of 
securing  the  same  object. 

His  scheme  was  merely  the  use  of  an 
inductance  in  series  with  a  condenser 
arranged  in  parallel  to  the  plate  and  fila- 
ment of  the  vacuum  tube.  The  induct- 
ance used  in  the  plate  paralleling  scheme 
could  be  placed  either  in  inductive  rela- 
tion to  the  grid  or  secondary  coil,  or  it 
could  be  placed  away  from  that  circuit. 
Better  control  was  found  by  putting  the 
plate  or  tickler  coil  in  inductive  relation 
secondary.  Several  years  later  Reinartz 
to  the  took  up  the  Weagant  and  did  a 
good  deal  of  intensive  work  with  it,  work- 
ing it  over  into  a  single  circuit  instead 
of  the  loose  coupled  original. 

He  added  the  choke  coil  in  the  plate 
circuit  to  assist  in  easy  control  of  the 
tube. 

New  Circuits? 
Reinartz'  work  with  the  circuit  was  the 
signal  for  a  horde  of  eager-eyed  experi- 
menters to  start  turning  out  circuits  at 
the  rate  of  one  each  day  or  so,  few  of 
which  had  any  particular  merit.  We 
have  seen  many  instances  where  indi- 
viduals would  take  the  basic  Armstrong 
circuit,  transpose  the  position  of  the  B 
battery  and  the  phones,  or  else  the  B 
battery  and  the  plate  inductance,  and 
then  label  it  an  original  circuit.  It  used 
to  be  so  bad  that  conductors  of  technical 
departments  in  newspapers  were  putting 
on  the  market  wonderful  receivers  with  a 
fancy  name,  but  having  nothing  but  the 
basic  Armstrong  or  the  Weagant  sub- 
stitute. And  readers  used  to  deluge 
the  editor's  desk  with  new  and  novel 
circuits,  all  of  which  when  analyzed 
turned  out  to  be  the  basic  stuff. 

Public  Enlightened 

But  fortunately  this  condition  could 
not  persist.  The  public  became  more  and 
more  enlightened;  the  trimmers  and 
riff-raff  of  the  game  were  gradually 
eliminated  or  else  their  wings  clipped, 
and  today  the  radio  game  is  getting  to 
be  pretty  much  of  a  standardized  science 
in  which  the  public  cannot  for  long  be 
mis-informed  and  mis-led  without  dis- 
astrous consequences. 

If  you  don't  believe  it,  get  up  before 
a  gathering  of  radio  hounds  and  announce 
in  stentorian  tones  that  you  have  just 
developed  an  original  circuit. 

Seriously,  the  Weagant-Reinartz-et-al- 
system  has  proved  very  popular  prin- 
cipally on  account  of  the  simplicity  of 
regeneration  control,  by  means  of  a 
variable  condenser  which  can  make 
capacity  changes  in  the  circuit  with 
greater  finesse  than  the  rotation  of  a 
plate  coil  inside  of  the  secondary.  Grant- 
ing the  plate  coil  in  the  Weagant  combi- 
nation is  fixed,  it  is  possible  to  log  the  set. 
If  the  plate  coil  is  put  at  the  filament 
end  of  the  secondary,  the  wavelength 
is  not  thrown  out  when  copying  c.  w. 
signals. 


Radio  Trade  Association 
Meets 

Unquestionably  the  biggest  and  most 
enthusiastic  meeting  of  the  Radio  Trade 
Association  ever  held  since  the  organiza- 
tion came  into  being  was  held  in  the 
afternoon  of  May  28  at  Pontiac,  Michi- 
gan, the  members  of  the  Association 
being  the  guests  of  the  Jewett  Radio  & 
Phonograph  Company  of  Detroit  and 
Pontiac.  The  usual  attendance  of  the 
bi-weekly  meeting  of  the  Association 
was  more  than  doubled. 

The  meeting  began  with  a  luncheon 
served  in  the  Board  of  Commerce  of 
Pontiac,  as  a  compliment  from  the  Jewett 
Company.  During  the  luncheon,  short 
talks  were  made  by  E.  H.  Jewett,  Presi- 
dent of  the  Company,  S.  W.  Edwards, 
Secretary  of  the  Radio  Trade  Associa- 
tion, and  Howard  E.  Campbell,  Chief 
Radio  Engineer  and  Director  of  the 
Broadcasting     Division. 

In  his  short  talk,  Mr.  Jewett  expressed 
his  pleasure  for  having  such  a  large 
attendance  at  the  meeting  and  spoke 
briefly  of  the  trend  of  radio  manufactur- 
ing and  merchandising,  calling  attention 
to  the  fact  that  this  Company  was  in 
the  radio  business  to  stay,  to  produce 
products  of  quality  and  to  stand  back 
of  these  products  even  after  they  reached 
the  homes  of  the  consumers.  He  decried 
the  many  instances  in  which  "fly-upon- 
night"  manufacturers  and  dealers  have 
put  into  the  hands  of  the  consumers 
merchandise  of  a  questionable  character, 
which  in  the  long  run  has  tended  to 
lower  the  confidence  of  the  general  public 
in  almost  everything  pertaining  to  radio. 
This,  he  said,  was  on  the  mend,  and  before 
long  the  dawn  of  a  staple  industry  which 
has  as  its  aim — to  serve  every  American 
home — is  in   sight. 

In  replying  to  the  brief  remarks  of  the 
President  of  the  Company,  Mr.  Edwards, 
representing  the  Radio  Trade  Association 
of  Michigan,  graciously  accepted  the 
courtesies  that  had  been  shown  the 
members  of  the  Association,  and  ex- 
pressed a  desire  for  closer  and  better 
affiliations  among  the  representatives 
of  the  various  divisions  of  the  radio 
industry. 

Some  of  the  intricacies  of  broadcasting 
and  a  few  of  the  humorous  incidents 
that  are  always  occurring  in  the  studio 
of  the  broadcasting  station,  but  are 
never  brought  to  light  so  far  as  the  radio 
audience  is  concerned,  were  enumerated 
by   Mr.   Campbell. 

Following  the  meeting  in  the  Board 
of  Commerce,  the  officials  of  the  Com- 
pany and  the  members  of  the  Associa- 
tion went  to  the  Jewett  factory,  one  of 
the  most  modern  radio  factories  in  the 
country,  located  on  the  outskirts  of  the 
citv  of  Pontiac.  Here  they  were  taken 
through  the  factory  proper,  two  units 
of  which  are  completed  and  then  shown 
through  the  broadcasting  station  of  the 
Company,  which  will  come  on  the  air 
early  in  July.  This  station  will  be  of  the 
latest  type  Western  Electric  equipment, 
having  an  antenna  input  of  five  thousand 
watts. 

Between  the  towers,  which  have'now 
reached  one-third  of  their  two  hundred 
foot  height,  the  operators  of  the  station 
and  workmen  were  laying  some  ofTthe 
six  thousand  feet  of  ground  wire  required 
for  the  station.  There  they  watched 'a 
specially  designed  instrument  sinking 
the  wire  a  foot  into  the  ground'as  fast 
as   the   tractor   could   pull   it. 


Li     $ 

v     «0 


36 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


A  Two-Tube  Ultra  Audion 

By  JOHN  B.  RATHBUN 


L  F  the  twenty-eight  radio  receiving 
circuits  known,  as  ultra-audions, 
there  is  one  simple  circuit  that  is 
most  commonly  known  to  the  radio 
novice.  This  is  the  ultra-audion, 
alias  the  "Little  Wonder  Circuit," 
alias  the  "Radio  Demon,"  alias  the 
"Ultraphone,"  alias  the  "Gibbon's  Os- 
cillator." It  has  also  paraded  under  the 
peculiar  cognomen  of  the  "Carpet  of 
Bagdad,"  which  however,  has  nothing 
to  do  with  the  photoplay  of  that  name. 
In  fact,  every  time  that  any  dealer 
wishes  to  bring  out  a  simple,  cheap  and 
efficient  distance  getter,  he  drags  out 
the  ultra-audion  and  labels  it  with  his 
pet  name.  Results  are  about  as  certain 
with  this  little  outfit  as  is  possible  with 
any  simple  combination  of  variable 
condenser  and  single  inductance  coil; 
hence  it  is  ideal  in  its  own  sphere  of  use- 
fulness. 

One  thing  that  appeals  particularly  to 
the  poor  hook-up  editor  is  the  fact  that 
you  have  twenty-eight  chances  of  avoid- 
ing a  mistake  in  connecting  it  up;  in 
fact,  it  is  almost  impossible  to  get  it 
hooked  up  so  that  it  will  not  percolate  to 
some  extent  unless  you  should  get  the 
"B"  battery  across  the  filament  of  the 
tube.  Confidentially,  it  can  also  be  used 
as  a  transmitter  over  a  short  range  by 
connecting  a  microphone  in  the  ground 
circuit.  This  statement  will  probably 
bring  down  the  united  curses  of  entire 
neighborhoods  on  my  head  for  bringing 
it  to  our  readers'  attention,  but  I  thought 
you  ought  to  know  it.  Radiate?  I'll 
say  she  does.  When  the  village  pest 
starts  twisting  the  dials  of  this  outfit 
you  will  see  your  neighbors  climbing  up  to 
the  house  tops  taking  down  their  aerials. 

But  It  Works! 

TT  may  be  noisy  and  it  may  radiate, 
J-  but  it  certainly  gets  the  DX.  Like 
every  other  circuit  having  distance 
getting   qualities,    it    is   noisy,    unstable, 


A  New  Version  of  an 
Old  Reliable  Hookup 


and  not  particularly  selective  where  there 
is  much  strong  local,  but  it  will  reward 
you  by  pulling  in  stuff  that  you  would 
otherwise  only  read  about.  Dollar  for 
dollar,  and  tube  for  tube,  you  can  cover 
more  mileage  with  the  ultra-audion  than 
any  other  set  I  know  of,  and  it  is  on  thi? 
basis  alone  that  I  recommend  it.  For  a 
single  circuit  receiver  it  tunes  quite 
sharply,    and    is    selective    enough    when 


A  COMPLETE  BLUEPRINT 
SECTION  IN  THE 

ANNUAL 

A  thirty-two  page  blueprint 
section,  replete  with£tried  hook- 
ups and  sixteen  J  pages  of  blue- 
prints in  actual  color,  is^the  out- 
standing feature  of  the  RADIO 
AGE  ANNUAL^for;i925,  now  avail- 
able at  $1.00  a  copy.  You  can 
use  these  blueprints  as  real  work- 
ing drawings,  for  they  are  clear 
and  easy  to  follow.  Sixteen  pages 
of  blueprints  Fare  J  worth  many 
times  the  purchase  price  of  the 
ANNUAL.  _ 

In  addition  to  the  blueprint 
section,  there  are^hundreds  of  new 
hookups  for  beginner  and  expert 
in  the  ANNUAL\for.  1925.  Every 
class  of  radio  fan  will  find  his 
wants  fulfilled. 

The  first  edition  consists  of  a 
limited  number  of  copies,  which 
are  being  exhausted  quickly.  Send 
your  dollar  NOW  if  you  want  to 
be  assured  of  getting  your  copy 
of    the    RADIO    AGE    ANNUAL. 


fifty  miles  or  more  away  from  a  broad- 
casting station,  but  in  congested  local 
traffic  it  is  not  much  good,  and  in 
Chicago  it  is  practically  useless  except 
on     silent     nights. 

In  Chicago,  the  complete  set  of  parts 
have  been  sold  retail  for  $6.75  for  the 
single  tube  ultra,  and  from  $10.00  to 
$12.00  for  the  two  tube  set.  This,  of 
course,  does  not  include  headset,  tubes 
or  battery.  This  is  not  so  much  greater 
than  the  cost  of  building  a  crystal  set, 
except  for  the  tubes  and  battery,  and 
you  get  real  tube  results  with  a  few 
dollars  invested. 

I  do  not  recommend  the  single  tube 
ultra-audion  for  two  reasons.  (1)  Be- 
cause the  phone  impedance  forms  part 
of  the  inductive  balance  in  the  circuit 
which  is  upset  when  two  or  more  pair  of 
phones  are  inserted  into  the  detector 
circuit,  and  (2)  because  there  is  a 
considerable  body  capacity  effect  in  the 
phone  cords  when  the  headset  is  con- 
nected directly  to  the  detector  tube. 
By  using  an  audio  transformer  as  the 
inductance  for  the  first  tune,  we  do 
away  with  both  difficulties  and  the  re- 
ceiver is  therefore  much  more  flexible 
in  regard  to  the  output  connections. 
A  single  tube  ultra  will  not  carry  two 
sets  of  phones  satisfactorily,  either  in 
series  or  in  parallel,  for  this  varies  the 
feed-back  potential  and  therefore  the 
degree  of  regeneration.  When  working 
full  blast  on  distance,  the  phone  cord 
capacity  may  be  so  great  that  the 
station  will  be  tuned  in  or  out  every 
time  that  you  move  your  head  or  touch 
the  headset  with  your  fingers,  but  the 
introduction  of  an  audio  transformer  and 
second    tube    will    prevent    this    trouble. 

Wide  Wave  Range 

TN  Fig.  1  is  a  picture  diagram  of  the  two 
*-  tube  ultra-audion  using  a  spiderweb 
coil  or  "pure  inductance"  for  the  tuning 
unit.      This  type   of  coil   is   far  superior 


Blueprints  of  the  Two-Tube  Ultra  Audion  on  Pages  Following 


Here  is  another  of  the  forms  by  which  it  was  originally  attempted  to  get  around  the  basic 
Armstrong.  It  is  known  as  the  ultra-audion  and  is  nearly  as  old  as  the  Armstrong  itself.  But 
it  has  changed  its  name  oftener  than  a  bootlegger.  It  also  obtrudes  its  presence  upon  the 
neighborhood  in  about  the  same  degree  as  the  neighborhood  cat.  It  is  fine  for  the  wide  open 
spaces  where  men  are  men  and  single  circuits  are  welcome,  but  not  much  for  the  crowded  city 
sections  when  it  is  expected,  on  account  of  superior  intelligence  and  enlightenment,  the  cliff- 
dweller  will  observe  the  golden  rule  of  radio — "Don't  be  a  tweeter." 

Mr.  Rathbun  has  efficiently  described  the  circuit  in  the  article  above,  so  this  leaves  only 
the  opportunity  of  calling  your  attention  to  the  subscription  contest  on  page  18.  Read  it  and 
go  out  after  the  recruits;  the  RADIO  AGE  family  sholud  be  expanded  and  the  readers  are  the 
most  logical  ones  to  do  it,  especially  since  they  have  a  chance  at  some  of  the  monthly  prizes. 


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RADIO   AGE/or  August,  1925 


The  Magazine  of  the  Hour 


37 


A  New  Version  of  the 
Ultra  Auction 

to  the  common  homemade  coil  wound  on 
a  tube.  With  a  23  plate  or  0.0005  mf 
variable  condenser  (C),  the  range  will 
be  from  200  meters  to  well  over  700 
meters  with  the  specified  coils.  It  will 
be  well  to  use  a  vernier  type  of  condenser 
so  that  the  maximum  signal  strength 
can  be  more  easily  developed  by  closer 
tuning. 

When  a  spiderweb  coil  is  used,  such 
as  supplied  by  our  advertisers,  a  total 
of  eighty-five  turns  should  be  specified, 
tapped  at  such  points  as  will  properly 
cover  the  range  of  wavelengths.  The 
tap  switch  (TS)  makes  closer  tuning 
possible  over  a  greater  wavelength  range 
than  an  untapped  coil,  but  a  plain  coil 
can  also  be  used  with  a  total  of  75  to 
100  turns.  A  75  turn  or  a  100  turn 
honeycomb  coil  will  be  right,  but  the 
100  turn  is  probably  the  better  for  the 
broadcast  listener  with  wavelengths  aver- 
aging about  360  meters.  This  is  one  of 
the  advantages  of  the  ultra-audion;  it 
can  be  used  over  a  very  broad  band  of 
wavelengths  by  simply  substituting  coils 
of  various  numbers  of  turns.  Special 
tapped  honeycombs  can  be  used  as  well 
as  the  plain,  untapped  variety.  Tapping 
is  not  a  necessity  but  simply  a  convenience. 

Wound  on  Cardboard 

When  the  coil  is  wound  on  a  cardboard 
tube,  a  diameter  of  from  2.5  inches  to 
3  inches  can  be  used,  and  we  should  have 
about  120  turns  tapped  at  about  ten- 
turn  intervals  after  the  fiftieth  turn. 
Thus,  we  will  tap  at  60  turns,  70  turns, 
SO  turns,  90  turns,  100  turns,  110  turns 
and  at  the  finish.  This  will  give  us  seven 
tapping  points,  including  one  end.  To 
conserve  space  use  No.  26  D.  S.  C.  wire, 
but  if  desired,  No.  24  or  No.  22  can  also 
be  used.  The  low  loss  idea  can  be 
introduced  by  giving  the  coil  a  good  coat- 
ing of  celluloid  varnish  (not  shellac), 
and  then  slipping  the  coil  off  of  the  tube 
when  dried.  The  varnish  can  be  made 
by  dissolving  bits  of  celluloid  in  amyl 
acetate,  which  produces  a  fairly  good 
non-capacitative  coating.  If  shellac 
is  used,  you  will  get  no  results  at  all. 
The  paper  tube  can.  be  slit  lengthwise 
before  winding,  and  when  the  coil  is 
dry,  we  can  easily  separate  it  from  the 
tube  by  breaking  down  the  latter  at  the  slit. 

Now  comes  an  important  precaution 
against  body  capacity.  The  stator  or 
stationary  plates  (s)  of  the  variable 
condenser  (C)  should  be  connected  to 
the  grid  line  (5)  while  the  rotor  or  moving 
plates  should  be  connected  to  ground  or 
to  line  (23).  If  this  is  not  done,  you  will 
be  annoyed  with  "body  capacity"  so  that 
when  you  put  your  hand  anywhere  near 
the  dial  it  will  detune  or  give  a  shrill 
"Whee-ee-ee"  and  break  into  violent 
oscillations. 

For  the  best  results  the  grid  condenser 
(K)  should  be  a  variable  condenser  or 
one  of  the  semi-variable  grid  condensers 
now  placed  on  the  market  for  this  pur- 
pose. When  the  capacity  is  once  adjusted 
to  the  retirements  of  the  particular  tube 
in  the  socket  it  does  not  frequently  need 
readjustment  except  on  wide  variations  of 


wavelengths,  and  the  latter  type  of  con- 
denser is  perfectly  correct.  However,  a 
fixed  condenser  of  0.00025  mf  capacity 
will  do  very  nicely  and  is  used  in  most  of 
the  ultra-audions.  A  variable  grid  leak 
at  (GL)  must  be  used  under  all  condi- 
tions as  the  tube  is  very  critical  to  the 
resistance  of  the  leak. 

The  Plate  Voltage 

NOW  just  a  word  in  regard  to  the 
voltage  of  the  "B"  or  plate  battery 
(B).  If  we  are  to  avoid  excessive  radia- 
tion from  our  aerial,  and  reduce  inter- 
ference to  a  minimum,  we  must  nor  use 
over  22.5  volts  on  the  detector  tube  (Tl). 
This  result  is  attained  by  taking  an  inter- 
mediate "B"  battery  tap  at  the  point 
(+22)  at  the  22-volt  section  of  the 
battery,  as  shown.  If  maximum  amplifi- 
cation    is     required     without     regard    to 


Working  Blueprints 
of  this  famous 

ULTRA-AUDION 
HOOKUP 

Are  to  be  found  on 
pages  38  and  39 

Another  set  of 
BLUEPRINT  SURPRISES 
in  September  RADIO  AGE 


radiation,  then  we  can  put  the  full  "B" 
voltage  on  both  tubes  by  connecting 
(  +  B)  of  the  transformer  with  the  (  +  67) 
of  the  battery  by  means  of  the  wire  (22). 
If  you  love  your  neighbors,  don't  do 
this  anywhere  except  in  the  country 
where  you  are  at  least  five  miles  from 
the  nearest  receiving  set.  At  least  45 
volts  should  be  used  on  tube  (T2)  and 
preferably  from  67.5  to  90  volts  so 
that  we  gain  the  maximum  audio  amplifi- 
cation. The  high  voltage  on  (T2)  has 
no  radiating  effect. 

Owing  to  the  fact  that  full  control 
of  the  regeneration  is  had  by  the  adjust- 
ment of  rheostat  (Rl)  it  is  sometimes  a 
good  policy  to  make  this  a  vernier  rheo- 
stat, but  fair  results  will  be  obtained 
from  a  plain  rheostat  of  the  proper 
resistance.  The  rheostat  (R2)  is  not 
critical  and  any  type  can  be  used  here. 
The  resistance  of  the  rheostats  depends 
upon  the  type  of  tube  used.  Any  tube 
can  be  used  for  the  detector  (Tl)  but 
the  amplifier  (T2)  must  be  some  hard 
amplifier  such  as  the  "11, ""12, ""199,"  or 
"201A"  type.  For  small  sets  the  "11" 
and  the  "12"  tubes  work  very  well,  but 
of  course  the  201A  is  preferable  where  a 
storage  battery  is  justified.  The  soft 
"200"  tube  is  probably  a  more  sensitive 
detector   at    (Tl)    but    it   is   more   critical 


and  difficult  to  manage  and  also  takes 
more  current  than   the  other  tubes. 

Any  good  make  of  audio  transformer 
can  be  used  at  (AT)  with  a  ratio  of  from 
5-1  to  6-1.  This  single  stage  of  audio 
amplification  is  sufficient  to  get  good 
volume  on  distance,  and  with  local 
stations,  very  good  loud  speaker  volume 
can  be  obtained.  In  fact,  I  have  had 
fair  loud  speaker  volume  on  local  with 
the  detector  tube  alone,  so  intense  is 
the  regeneration  in  the  ultra-audion 
circuit.  The  output  (p-pO  is  connected 
to  the  phones  or  speaker,  as  may  be 
desired.  No  jack  has  been  placed  be- 
tween the  detector  and  audio  stage,  as 
this  would  introduce  "unbalance"  into 
the  circuit  and  also  give  phone  cord 
capacity  effect,  which  is  disastrous  to 
proper  performance. 

Only  a  very  small  panel  is  required, 
and  the  set  has  been  assembled  satis- 
factorily on  a  6"xl0"  and  6"xl2"  size 
with  plenty  of  room  for  all  of  the  parts. 
Its  portability  is  a  great  feature  and  the 
small  panel  permits  of  placing  batteries 
and  all  in  a  comparatively  small  cabinet, 
thus  making  the  set  self-contained  and 
handy  to  move  about.  When  the  detector 
is  used  alone,  without  audio  amplification, 
a  6  x7  or  a  7  x9 '  panel  will  be  ample 
for  the  accommodation  of  the  parts. 

In  regard  to  the  tap  switch  (TS),  I 
wish  to  say  that  the  number  of  contact 
buttons  used  will  depend  upon  the  num- 
ber of  tapping  points  on  the  coil  and  this 
is  likely  to  vary  somewhat  among  differ- 
ent makes  of  coils.  I  have  shown  seven 
taps  on  the  drawings,  but  this  must  be 
regulated  by  the  coil  used.  Some  com- 
mercial honeycombs  use  five  taps,  others 
use  seven  taps  and  there  are  coils  with 
nine  taps.  It  should  be  understood 
that  the  number  of  taps  connected  to 
the  contacts  is  one  less  than  the  total 
number  of  wire  ends,  since  one  end  of 
the  coil  is  permanently  connected  to 
the  aerial  by  wire  (1). 

In  Fig.  1  is  the  picture  diagram  by 
which  the  most  inexperienced  should  be 
enabled  to  hook  up  the  set.  Fig.  2  is  a 
conventional  drawing  using  symbols, 
while  Fig.  3  is  an  isometric  view  showing 
the  back  of  the  panel  and  the  arrange- 
ment of  the  apparatus  as  it  actually 
appears,  but  it  should  not  be  used  in 
making  the  actual  connections,  as  some 
of  the  wires  and  connections  are  hidden 
from  view.  For  making  connections,  use 
either  Fig.  1  or  Fig.  2.  An  isometric  is 
very  useful  for  gaining  an  idea  of  the 
general  arrangement  of  the  parts  and 
main  runs  of  wire,  but  if  it  is  made  so 
that  all  of  the  wires  are  in  plain  view, 
then  the  view  is  so  distorted  that  its 
principal  value  is  destroyed.  AH  sense  of 
proportion  and  scale  are  lost  in  this  way. 

TN  GENERAL,  it  is  best  to  place  a 
-*-  spiderweb  coil  (LI),  or  "pure  induct- 
ance" as  it  is  sometimes  called,  at  right 
angles  to  the  condenser  (C),  for  by  this 
arrangement  practically  all  electrostatic 
coupling  between  the  parts  is  eliminated. 
The  audio  transformer  should  be  kept 
away  from  (LI)  to  prevent  noise.  It 
seems  almost  unnecessary  to  state  that 
all  connections  must  be  soldered,  and 
soldered  without  acid,  but  I  will  say  it 
anyway  for  the  benefit  of  the  beginners. 


-A      +A       -B      +22    +67 


x — \~7 
jeri/U-  \  I  / 

V 


F/6./ 

Plan  View  of  Ul.tra-4ud/on 

IN  ORDER  TO  SHOW  THE  OUTRL/T  CO/V/YECT/O/XS FOR 
E/THER  <Js)C/TS  OR  &//VO//V6  ROSTS /4S  M4V8E  OE~ 
S/RED,  WE  SHOW  POSTS  //V  FAS./  /WO  iMCtr  IN  F/6. 2. . 


OUTPUT 
BIND.  POSTS 


II 


P  OUTPUT 

SINS.  CII5O.0/4CK 


F/6. 2 
SCHEMATIC  DIAGRAM  of 

Ul  tra-Audion 

SHOW/N6  /?£CEIVE/?  WITH  ONE  STAGE:  Of* 
/IC/D/O  */VD  EGV/FF'EiO  WITH  TR#/YSM/T- 

TE&roe  sho/?t- z&wge:  ^^d/o/^/zone. 


O.B.  F^}7~FBOA/ 


40 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


An  Aperiodic  Variometer  Set 


TUNING  the  grid  circuit  inductively 
by  means  of  a  variometer  is  noth- 
ing new  in  radio.  In  fact,  this  is 
practically  as  old  as  the  use  of  the  fixed 
inductance  tuned  by  a  condenser,  but  the 
idea  has  considerable  merit  owing  to  the 
fact  that  it  is  possible  to  establish  higher 
potentials  on  the  grid  of  the  tube  in  this 
way.  Thus,  the  incoming  signal  has  more 
effect  on  the  tube  grid  when  capacity  is 
lacking  in  this  circuit  than  when  a  vari- 
able condenser  is  used  for  tuning  the  cir- 
cuit to  wavelength.  Better  results  are 
therefore  obtained. 

In  the  oldei  circuits,  the  grid  vari- 
ometer was  used  as  a  tuning  agent  for 
single  circuit  sets  or  else  it  was  used  in 
connection  with  the  standard  type  of 
tapped  variocoupler  where  the  additional 
losses  introduced  rather  than  offset  the 
inherent  advantages  of  the  variometer 
inductance.  Used  in  a  single  circuit  set, 
there  was  a  loss  of  selectivity.  Used  with 
a  standard  variocoupler,  the  losses  in  the 
taps  and  tap  switches  often  offset  the  in- 
creased efficiency  of  the  variometer.  In 
other  words,  the  variometer  was  never 
used  so  that  it  was  allowed  to  develop 
its   full   possibilities   in   the   grid   circuit. 

Variometer  "Switched" 

After  carefully  going  over  this  matter 
and  experimenting  with  various  combi- 
nations of  variometers,  it  was  finally  de- 
cided to  make  the  variometer  an  integral 
part  of  the  primary  and  secondary  tuning 
circuits  so  that  the  variometer  formed  the 
secondary  winding  of  the  coupler,  while  a 
few  turns  of  wire  at  one  end  of  the 
variometer  acted  as  an  "aperiodic"  pri- 
mary coil.  No  condenser  was  needed, 
and  the  full  selectivity  of  the  vario- 
coupler was  attained  without  losses  in  the 
tapped  coils  and  rotor.  The  construction 
is  simplicity  itself  and  lives  up  to  ex- 
pectations   in    every    way. 


By  JOHN  B.  RATHBUN 

Applying  Variometer 
Idia  to  Good  Circuit 


LTAVING  progressed  this  far,  the  next 
*■■*-  thing  was  to  apply  the  idea  to  some 
specific  circuit  where  its  full  possibilities 
could  be  developed  without  complicating 
the  controls.  Various  circuits  were  in- 
vestigated and  finally  it  was  decided  that 
this  circuit  offered  an  excellent  oppor- 
tunity for  the  application  when  the  plate 
circuit  was  tuned  by  a  second  vario- 
meter. While  the  original  Wizard  circuit 
worked  very  well  without  the  plate 
variometer    and     with     direct    indue- 


HOW  TO  USE  RADIO  AGE 
BLUEPRINTS 

The  RADIO  AGE  blueprints  are 
arranged  in  the  ANNUAL  so  that 
they  may  be  used  as  actual  work- 
ing drawings  by  the  set-builder. 
For  instance,  each  hookup  de- 
scribed in  the  RADIO  AGE  AN- 
NUAL blueprint  section  consists 
of  four  pages,  two  of  which  are  ex- 
planatory pages  and  the  other  two 
real  blueprints. 

The  Aperiodic  Variometer  set, 
for  example,  is  described  in  the 
text  on  this  page  and  on  page  41, 
while  the  blueprints  for  this  hook- 
up may  be  found  on  the  two 
pages  following. 

Blueprints  in  the  ANNUAL  blue- 
print section  are  arranged  in  the 
same  manner  for  the  convenience 
of  the  reader. 


tive  feed-back,  yet  the  addition  of  the 
plate  variometer  made  the  set  even  more 
selective  than  before  and  greatly  in- 
creased the  signal  strength.  Regenera- 
tion is  more  easily  controlled  without 
accurate  filament  current  adjustment, 
and  by  the  combined  effects  of  the  feed- 
back coil  and  the  tuned  plate  circuit,  a 
condition  of  resonance  is  more  accurately 
approached  in  both  circuits  and  the  im- 
pedance of  the  circuit  can  be  made  more 
nearly  the  theoretical  zero  necessary  for 
the  establishment  of  maximum  voltages. 
In  Fig.  1  on  page  34  we  show  a  picture 
circuit  of  the  set  called  the  "Aperiodic 
Variometer  Set"  with  the  two  variometers 
used  for  the  grid  and  the  plate  respec- 
tively. For  maximum  results  and  for 
loud  speaker  operation  at  fair  distances 
one  stage  of  audio  amplification  has 
been  added  permanently  which  gives  an 
excellent  two-tube  set  with  great  volume 
and  a  very  considerable  range.  Of  course, 
the  detector  tube  can  be  used  alone  or 
else  another  stage  of  audio  amplification 
can  be  added,  but  for  the  best  results  for 
a  given  investment,  I  believe  that  the  cir- 
cuit is  at  its  best  the  way  that  it  is  shown 
in  the  figures.  It  is  certain  that  the  addi- 
tion of  radio  frequency  steps  only  slightly 
increases  its  range  and  that  the  expense 
and  trouble  of  adding  the  radio  stages  is 
not  justified  by  the  slight  increase  in  per- 
formance. 

Variometer  as  Secondary  Coil 

In  Fig.  1,  page  34,  is  the  grid  variom- 
eter marked  (VI)  which  is  used  for 
tuning  the  set  to  wavelength,  this 
variometer  acting  as  the  secondary  cir- 
cuit coil  of  a  two-circuit  receiver.  At  the 
left  is  the  aperiodic  primary  coil  (L)  con- 
sisting of  about  25  turns  of  No.  26 
D.  S.  C.  wire  wound  on  a  four-inch  diam- 
eter bakelite  or  cardboard  tube.  In  ad- 
dition  to  acting  as  the   primary  of   the 


Blueprints  for  the  Aperiodic  Variometer  Set  on  Pages  Following 


Now  We'll  Tell  One! 

It's  just  like  this;  you  pride  yourself  on  being  a  subscriber  of  a  magazine  with  a 
large  circulation.  No  magazine  ever  has  a  large  enough  one,  regardless  of  how  high 
in  the  hundred  thousands  its  circulation  runs. 

So  at  this  time  of  the  year,  when  you  are  revamping  your  set  for  the  Winter, 
you  have  a  chance  to  add  to  RADIO  AGE'S  family  of  readers  by  rounding  up  annual 
subscribers  and,  incidentally,  trying  for  some  of  the  prizes  offered  each  month  for 
the  reader  who  brings  in  the  largest  number  of  paid  up  yearly  subscriptions. 

On  page  18  you  will  find  the  terms  of  the  contest.  Each  reader  and  contestant 
knows  perhaps  a  lage  number  of  individuals  interested  in  radio  who  do  not  sub- 
scribe to  this  magazine.  Just  a  little  exertion  on  your  part  and  two  things  are  ac- 
complished: You  win  one  of  the  prizes  and  we  add  members  to  our  radio  family 
circle. 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


41 


An  Aperiodic 
Variometer  Set 
for  Efficiency 


circuit,  the  coil  (L)  also  acts  as  the 
tickler  or  feed-back  coil  which  induces 
additional  impulses  into  the  secondary 
by  connections  with  the  plate  circuit. 
The  tube  of  (L)  is  fastened  to  the  side 
of  a  standard  molded  variometer  in  any 
way  that  may  be  convenient  with  the  in- 
strument used.  The  distance  between  the 
coil  and  variometer  is  not  critical  and 
can  be  made  as  shown.  Any  type  of 
molded  or  honeycomb  variometer  can  be 
used,  but  a  wooden  variometer  is  not 
usually  practical  owing  to  the  great  clear- 
ance space  ordinarily  found  between  the 
rotor  and  stator  of  the  wooden  vario- 
meters. 

AT  (V2)  we  have  the  standard  plate 
**■  variometer  used  for  controlling  re- 
generation and  for  varying  the  inductance 
of  the  plate  circuit.  This  can  also  be 
any  standard  type  of  molded  or  honey- 
comb variometer  but  usually  the  induc- 
tance value  must  be  greater  than  can  be 
attained  with  the  ordinary  wooden  va- 
riometer. Very  frequently  the  inductance 
of  wooden  variometers  is  so  low  that  they 
have  absolutely  no  effect  on  the  regen- 
eration when  turned  in  any  direction,  and 
this  fact  is  emphasized  for  the  benefit 
of  those  of  our  readers  who  may  attempt 
the  building  of  the  circuit  with  this  type 
of  variometer.  The  tuning  is  exceedingly 
sharp  and  fairly  critical  so  that  the  addi- 
tion of  a  "Tiny  Turn"  vernier  button  to 
the  dials  of  the  variometers  will  be  of 
importance,  or  any  other  type  of  geared 
vernier  adjustment  which  can  be  con- 
veniently attached  to  the  dials. 

At  (Kl)  we  have  the  usual  type  of 
grid  condenser  with  a  capacity  of  from 
0.00025  to  0.0005  mf.,  the  former  value 
usually  proving  best  for  the  UV201A  and 
UV199  tubes.  Tube  (Tl)  is  the  detector 
tube  which  is  controlled  by  the  filament 
rheostat  (Rl).  Of  course  maximum  re- 
sults are  obtained  with  the  power  tubes 
operated  by  a  storage  battery  such  as  the 
UV201A,  but  very  good  results  can  also 
be  obtained  by  the  small  dry  cell  tube 
known  as  the  UV199.  The  WD  11  and 
WD12   are  not  so    selective    but    can    be 


used  if  the  other  tubes  are  not  practical 
under  the  given  operating  conditions.  The 
soft  detector  tubes  such  as  the  UV200 
will  not  give  as  much  volume  on  strong 
signals  as  the  UV201A  or  the  UV199  for 
the  reason  that  we  cannot  carry  such  high 
plate  voltages  on  the  soft  detector  tubes. 

Distortion    Eliminated 

As  shown  in  the  diagram,  45  volts  are 
used  on  the  detector  tube  (Tl)  and  90 
volts  on  the  audio  amplifier  tube  (T2). 
This  gives  the  maximum  results  without 
distortion  when  the  UV201A  and  UV199 
are  used.  Using  a  higher  voltage  on  the 
detector  tube  (Tl)  gives  a  somewhat 
greater  signal  strength  on  local  stations 
but  it  also  introduces  undesirable  tube 
noises  and  distortion.  Lower  voltages 
than  those  specified  naturally  give  weaker 
signals,  and  the  weaker  voltages  on  the 
plate  also  reduce  the  selectivity  of  the 
circuit. 

The  grid  leak  (GL)  is  of  the  pencil 
mark  or  other  variable  leak.  Its  value  is 
to  be  adjusted  until  the  signals  are  strong- 
est and  clearest.     If  the  resistance  is  too 


USE  THE  ORIGINAL 
BLUEPRINTS 

On  Pages  42  and  43 

to  make  This 

Aperiodic  Variometer  Set. 


high,  then  there  will  be  noises  and  the 
reception  will  have  a  whiney  tone.  If 
the  resistance  is  too  low,  then  too  much 
radio  frequency  current  will  be  bypassed 
and  the  signal  strength  will  be  reduced. 
The  proper  value  for  any  one  tube  can 
only  be  tried  by  direct  experiment. 

HpHE  aerial  connection  at  (ANT)  to- 
*■  gether  with  the  ground  (GND)  and 
battery  connections  are  placed  at  the  rear 
of  the  set,  thus  allowing  all  wires  to  enter 
the  rear  of  the  cabinet  and  improve  the 
appearance  of  the  receiver.  The  binding 
posts  at  the  rear  are  mounted  on  two 
strips  of  bakelite  or  hard  rubber  about  1 
inch  to  1  1-4  inch  wide  and  about  3-16 
inch  thick.  The  strips  are  raised  above 
the  surface  of  the  bottom  board,  so  that 
no  metal  parts  or  wires  will  come  into 
contact  with  the  wood.  This  construc- 
tion is  clearly  shown   in  both   Fig.   1   and 


Fig.    2,    page    35,    the    latter    being    the 
isometric  view  of  the  set. 

Audio     Amplification 

For  aid  in  picking  up  distant  stations 
at  good  volume  and  for  loud  speaker 
operation  on  local  and  at  moderate  dis- 
tances, one  stage  of  audio  frequency  am- 
plification has  been  added.  Stations  200 
miles  away  have  been  picked  up  with 
good  volume  on  the  loud  speaker  with 
the  single  amplifying  stage,  and  local 
comes  in  with  terrific  volume.  In  fact, 
local  stations  can  be  had  on  the  loud 
speaker  with  the  detector  tube  (Tl) 
alone,  but  as  will  be  explained,  it  is  con- 
sidered desirable  to  have  the  detector 
and  the  amplifier  connected  in  one  per- 
manent unit. 

A  five-to-one  ratio  audio  frequency 
transformer  is  shown  at  (AFT).  The 
primary  of  the  transformer  is  connected 
at  the  posts  (P)  and  (B)  to  the  detector 
circuit  at  the  output  wires  (e)  and  (f). 
The  secondary  of  the  transformer  is  at 
(G)  and-  (F),  and  is  connected  into  the 
circuit  of  the  amplifier  tube  (T2).  A 
three  cell,  4.5  volt  "C"  battery  is  con- 
nected in  the  grid  circuit  of  the  amplifier 
tube  for  biasing  the  grid  and  is  of  great 
assistance  in  clearing  up  the  reception  and 
for  obtaining  maximum  amplification.  In 
all  cases,  the  negative  (  — )  terminal  of  the 
"C"  battery  should  go  to  the  grid  (G)  of 
the  tube,  so  that  the  grid  will  receive  a 
negative  charge  or  bias.  The  output  or 
plate  (P)  of  the  tube  (T2)  goes  to  the 
phones  or  loud  speaker  (PH). 

In  laying  out  this  circuit,  it  was  con- 
sidered advisable  to  omit  the  usual  jack ' 
between  the  detector  tube  and  amplifying 
stage,  both  on  the  score  of  simplicity  and 
effective  operation.  While  both  tubes 
must  be  used  at  all  times  with  the  present 
arrangement,  yet  it  has  certain  advan- 
tages which  are  lacking  when  interme- 
diate jacks  are  installed.  For  example, 
there  are  no  losses  or  noises  due  to  imper- 
fect contacts  in  the  jacks,  and,  further,  as 
the  audio  stage  is  always  in  circuit,  there 
is  no  danger  of  detuning  a  distant  station 
when  the  audio  stage  is  plugged  in.  When 
a  jack  is  installed  after  the  detector,  and 
when  one  picks  up  a  faint  signal,  it  often 
happens  that  this  station  is  lost  when  a 
stage  or  two  of  audio  is  plugged  in  at  the 
jacks. 

In  this  arrangement,  this  cannot  hap- 
pen; and  when  the  reception  becomes  too 
strong,  we  have  merely  to  turn  down  the 
rheostats. 


>oopo°BQg<frg'googo-3<s<>a-3-a-a-a-B-&g-so&oo-a-: 


In  the  circuit  shown  here,  patterned  after  the  basic  Armstrong  with  a  few 
changes  made  by  Mr.  Rathbun,  the  energy  from  the  plate  is  fed  back  to  the  grid  cir- 
cuit through  the  aperiodic  primary.  The  absence  of  a  variable  across  the  secondary 
circuit  and  the  use  instead  of  a  variometer  increases  the  signal  voltage  on  the  tube 
grid. 

While  it  is  true  that  variometers  are  gradually  going  out  of  existence,  neverthe- 
less there  is  a  place  for  them  in  circuits  of  this  type,  and  many  an  experimenter 
will  never  rest  until  he  has  tried  out  the  scheme  outlined  above  by  the  conductor  of 
the  blueprint  section. 


P!| 


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44  RADIO  AGE  for  August    1925 


The  Magazine  of  the  Hour 

A  Tuned  Plate  Regenerative  Set 

By  JOHN  B.  RATHBUN 


PROBABLY  one  of  the  most  effective 
types  of  straight  regenerative  cir- 
cuits and  the  simplest  to  build  is 
the  "tuned  plate"  type  in  which  the 
plate  circuit  is  tuned  to  resonance  with 
the  grid  circuit  by  means  of  a  variable 
inductance  such  as  a  variometer. 

While  I  do  not  present  this  well  known 
circuit  as  anything  new  in  its  entirety, 
yet  by  the  use  of  an  aperiodic  coupler 
I  am  sure  it  is  far  more  selective  than  the 
older  arrangement  with  a  variocoupler 
and  that  it  is  far  easier  to  tune.  With  a 
single  stage  of  audio  amplification  as 
shown  in  the  following  blueprints,  it  is 
an  exceedingly  good  DX  set  and  gives 
good  volume  on   distant   stations. 

Fig.  1  is  a  "picture  diagram"  of  the 
circuit  arranged  for  the  use  of  the  begin- 
ner. In  Fig.  2  is  a  schematic  diagram 
by  which  the  action  of  the  circuit  can 
be  more  easily  traced  out  by  those  exper- 
ienced in  handling  symbolic  diagrams. 
In  the  following  description  we  will 
refer,  therefore,  particularly  to  Fig.  2, 
although  all  three  views  bear  the  same 
reference  numbers  and  figures.  By 
this  system  of  lettering,  the  novice 
can  trace  .  back  and  forth  between 
the  two  diagrams  and  thus  become 
acquainted  with  the  conventional 
symbols  which  mean  so  much  to  the 
experienced    radio    man. 

How  to  Increase  Range 
'"PC)  BEGIN  with,  in  every  type  of 
-*-  straight  regenerative  circuit,  some  of 
the  amplified  plate  energy  is  fed  back 
into  grid  or  input  circuit  of  the  tubes, 
thus  increasing  the  potential  acting  on 
the  grid  of  the  tube  and  increasing  the 
range  and  signal  strength  of  the  circuit. 
For  example,  the  feeble  little  impulse 
induced  by  a  distant  station  in  the  aerial 
enters  the  antenna  binding  post  (ANT), 
passes  through  the  primary  coil  (LI)  and 
thence  to  ground  through  the  ground  post 
(GND)  and  the  dotted  ground  wire. 
That  is,  the  antenna  current  of  the  station 
to  which  the  set  is  tuned  passes  to  earth 
in  this  manner,  the  remaining  waves 
from  other  stations  being  "choked  back" 
by  the  self-inductance  of  the  system 

While  passing  through  the  primary 
coil  (LI),  the  current  sets  up  a  slight 
magnetic  field  which  threads  its  way 
through  the  turns  of  the  adjacent  sec- 
ondary coil  (L2)  of  the  tuner  and  "in- 
duces" or  creates  a  current  in  (L2).  The 
induced  current,  known  as  the  "secondary 
current"  acts  on  the  grid  of  the  tube 
through  the  grid  condenser  (CG)  and 
leak  (GL),  thus  causing  the  relatively 
powerful  local  battery  current  to  flow  in 
step  with  the  pulsations  in  the  aerial. 
In  effect,  the  tube  is  now  simply  a  form 
of  current  relay  or  valve  by  which  a 
feeble  pulsating  current  controls  a  rela- 
tively much  more  powerful  battery  cur- 
rent in  the  same  way  that  a  slight  move- 
ment of  the  hand  on  the  throttle  regulates 


Attaining  Selectivity 
With  An  Aperiodic 
Coupler  Added  To  a 
Well  Known  Circuit 


a  powerful  steam  engine  or  heavy  stream 
of  water. 

Inductance  is  Varied 

By  means  of  the  variable  condenser 
(CI)  the  inductance  of  the  coil  (L2)  is 
varied  so  that  the  circuit  can  be  tuned  or 
brought  into  step  with  the  frequency  of 
the  desired  station.  Coil  (L2)  by  acting 
inductively  on  (LI)  allows  only  the 
current  of  the  desired  frequency  to  pass 
to  earth.  The  number  of  turns  of  wire 
on  (L2)-  and  the  capacity  of  the  con- 
denser (CI)  determine  the  frequency  of 
the  circuit  or  the  wavelength  to  which 
it  may  respond.  Increasing  the  number 
of  turns  on  (L2)  or  increasing  the  capacity 
of  (CI)  increases  the  wavelength  of  the 
circuit.  In  the  same  way,  cutting  down 
the  number  of  turns  or  the  capacity  of 
condenser  (CI)  lowers  the  wavelength 
of  the  system.  As  it  is  far  easier  to  vary 
the  capacity  of  (CI)  than  to  alter  the 
number  of  effective  turns,  the  number  of 
turns  on  (L2)  is  fixed  at  some  value  so 
that  the  operation  of  (CI)  will  cover  the 
complete  band  of  broadcasting  wave- 
lengths. The  number  of  turns  on  (LI) 
is  not  of  so  much  importance  in  this 
respect,  but  in  any  case  the  turns  on 
(LI)  are  only  a  small  fraction  of  those  on 
(L2) 

Tubes  or  Crystal? 

TF  WE  were  to  depend  completely  upon 
-*-  the  signals  produced  in  this  way,  the 
vacuum  tube  would  not  be  so  very  much 
more  effective  than  a  crystal  detector 
for  the  reason  that  the  potentials  acting 
on  the  grid,  of  the  tube  are  very  feeble 
and  the  amount  of  battery  current  con- 
trolled would  be  correspondingly  small. 
The  "amplification"  or  "multiplication" 
of  the  tube  would  not  be  sufficient  to 
give  us  the  tremendous  distance  and 
signal  strength,  attained  by  the  tube 
when  used  in  a  "regenerative"  circuit. 
As  matters  stand  at  this  point,  the 
relayed  battery  current  from  the  "B' 
battery  (B)  passes  through  the  plate 
circuit  (12-13)  from  the  positive  side 
of  the  battery  (  +  ),  through  the  phones 
(PH)  and  back  to  the  tube  plate  at  (P). 
Inside  the  tube  this  current  flows  through 
the  vacuous  space  between  the  plate 
(P)  and  the  filament  (F)  and  returns  to 


the    negative    side    (— )    of    the  battery 
through  the  wires  (9-15).     Each  change 
in  the  rate  of  flow  in  this  circuit  moves 
the  diaphragms  of  the  phones  (PH)  and  ' 
thus  produces  a  sound. 

As  the  grid  (G)  of  the  tube  is  between 
the  plate  (P)  and  filament  (F),  it  acts 
like  a  valve  on  the  current  flow.  When 
the  aerial  current  induces  a  negative 
charge  on  (G),  the  current  flow  is  in- 
stantly checked.  When  the  incoming 
signal  imparts  a  positive  charge  to  (G) 
then  the  rate  of  flow  is  increased.  Each 
one  of  these  changes  in  the  rate  of  flow 
causes  movements  of  the  head-set  dia- 
phragms in  proportion  to  the  intensity 
of  the  incoming  waves.  During  this 
process  of  amplification,  the  incoming 
waves  are  "rectified"  or  checked  so  that 
only  waves  of  like  polarity  pass  through 
the  tube.  This  rectification  makes  it 
possible  to  develop  the  "modulation" 
or  voice  frequency  waves  upon  the 
phones,  as  the  frequency  of  the  radio 
frequency  waves  is  far  too  high  to  cause 
diaphragm  movement. 

Thus  the  tube  acts  in  two  roles.  In 
the  first  place  it  amplifies  the  incoming 
signal  waves,  and  (2)  the  tube  rectifies 
these  waves  so  that  the  voice  frequency 
impulses  are  developed  in  the  phones. 
We  are  not  directly  concerned  with  the 
rectification  factor  at  present  in  describ- 
ing the  regenerative  circuit;  hence  we 
will  let  this  matter  drop  and  consider 
only  the  means  of  amplification. 

Named  according  to  the  tube  elements 
with  which  they  are  connected,  we  have 
the  grid  circuit  at  (6-4-L2-7-8)  and  the 
plate  circuit  at  (11-VA-12-13-14-9-15-F). 
The  grid  circuit  is  the  "input"  of  the  tube 
while  the  plate  circuit  is  the  amplified 
"output."  As  the  current  in  the  plate 
circuit  is  very  much  heavier  than  that 
in  the  grid  circuit,  it  is  evident  that  the 
output  could  be  further  increased  if  we 
could  feed  some  of  the  plate  current 
back  into  the  grid  circuit  for  re-amplifica- 
tion in  the  tubes. 

Thus,  the  plate  current  could  be  am- 
plified a  second  time  with  corresponding 
increase  in  the  output,  and  this  is 
exactly  what  is  done  with  the  regenera- 
tive circuit.  In  one  type,  the  con- 
ductively  coupled  regenerative,  the 
plate  (P)  is  directly  connected  to  the 
grid  circuit  as  at  (4)  or  to  the  aerial  cir- 
cuit wire,  (2).  In  another  type,  the 
plate  current  is  led  through  a  "tickler" 
coil  which  acts  inductively  on  the  sec- 
ondary coil  (L2). 

In  the  present  "tuned  plate"  regenera- 
tive, the  feedback  is  "capacitative"; 
that  is,  the  plate  current  is  fed  into  the 
grid  circuit  through  the  internal  capacity 
of  the  tube,  control  being  had  by  means 
of  the  variable  inductance  or  variometer 
(VA.)  It  will  be  seen  from  Fig.  2  that 
the  grid  (G)  and  the  plate  (P)  are  like 
the   plates  of  a  condenser   in   regard  to 


Blueprints  of  the  Tuned  Plate  Regenerative  on  Pages  46  and  47 


RADIO  AGE  for  August,  1925 


A  New  Twist  to  the  Tuned 
Plate  Regenerator 

each  other,  and  therefore  grid  current 
can  be  fed  into  the  plate  circuit  or  plate 
current  can  be  fed  into  the  grid  circuit 
through  the  capacity  of  this  condenser, 
providing  that  the  two  circuits  are 
brought  nearly  into  step  or  "resonance" 
with  each  other. 

The  inductance  of  the  variometer 
(VA)  is  varied  until  the  grid  and  plate 
circuits  are  nearly  in  resonance,  and  when 
this  is  attained,  plate  current  feeds 
across  (P)  and  (G)  into  the  grid  circuit, 
producing  "regeneration."  This  causes 
a  tremendous  increase  in  the  output  of 
the  circuit  with  corresponding  increases 
in  range.  Without  regeneration  the 
ordinary  range  of  the  tube  would  prob- 
ably be  between  SO  and  100  miles.  Adopt- 
ing the  regenerative  principle  makes 
1,000  miles  an  ordinary  range  on  voice 
transmission  and  even  2,000  miles  is  not 
unheard  of. 

Units  and  Dimensions 

NOW  we  will  get  down  to  the  practical 
description  and  give  specific  instruc- 
tions for  the  building  of  this  receiver. 
We  can  now  include  the  picture  diagram, 
Fig.  1,  and  the  isometric  view  of  Fig.  3, 
which  shows  the  general  arrangement  of 
the  apparatus  behind  the  panel.  With 
the  exception  of  the  aperiodic  coupler 
(L1-L2)  all  of  the  apparatus  is  standard. 
There  is  nothing  at  all  critical  about  the 
set  and  even  the  inexperienced  need  not 
hesitate.  For  those  experimenters  who 
have  built  the  Baby  Heterodyne  II,  I 
will  say  that  the  same  tuner,  variometer 
and  condenser  can  be  used  for  building 
this  circuit,  and  several  of  our  readers 
have  already  done  this  successfully. 
The  aperiodic  coupler  has  been  described 
many  times  in  these  columns,  but  for 
the  benefit  of  the  newcomers,  I  will 
repeat  these  specifications. 

Both  the  primary  (LI)  and  the  sec- 
ondary coil  (L2)  are  wound  on  the  same 
cardboard  or  bakelite  tube.  This  tube 
is  about  three  inches  in  diameter  and 
four  inches  long.  Coil  (LI)  consists  of 
15  turns  of  No.  26  double  silk  covered 
wire,  wound  1-2  inch  from  one  end  of  the 
tube.  The  secondary  coil  (L2)  contains 
about  60  turns  of  the  same  size  wire 
and  is  started  about  1-2  inch  from  the 
end  of  coil  (L2).  In  other  words,  there 
is  1-2  inch  space  between  (LI)  and  (L2). 
Under  certain  conditions,  particularly 
with  long  aerials,  it  may  be  necessary  to 
reduce  slightly  the  number  of  turns  on 
(L2),  say  by  five  to  eight  turns,  in  order 
to  bring  in  stations  on  short  wavelengths 
around  the  200-meter  mark.  This  is 
best  determined  experimentally  at  the 
time  the  set  is  built,  owing  to  the  great 
variation  in  the  constants  of  commercial 
condensers  and  variometers. 

To  avoid  long  wires,  it  is  generally 
best  to  support  the  coil  on  the  back  of 
the  condenser  by  means  of  short  brass 
brackets  which  also  serve  as  the  con- 
nections (4-7)  between  the  coil  (L2)  and 
condenser  (CI).  The  jumper  wire  con- 
nection (3)  may  or  may  not  be  necessary, 
depending  upon  local  conditions,  but  as 
a    rule    this    is    desirable,    as    it    greatly 


reduces  body  capacity.  The  extreme 
outer  turn  (c)  of  coil  (L2),  the  end  far- 
thest away  from  the  primary  (LI)  should 
be  connected  to  the  grid  line  (4-5),  and 
it  should  be  particularly  noted  that  the 
"stator"  or  stationary  plates  of  (CI) 
should  be  connected  to  (c),  and  also 
(4-5).  If  this  is  not  done,  then  there  is 
likely  to  be  trouble  with  body  capacity. 

Any  standard  variometer  will  work 
well  in  this  circuit,  but  if  possible,  obtain 
a  "plate  variometer"  especially  designed 
to  work  in  the  plate  circuit.  This  vario- 
meter has  fewer  turns  of  heavier  wire 
than  the  "grid"  type  variometer.  How- 
ever, both  will  give  results  if  it  is  impossi- 
ble to  obtain  these  distinctive  windings. 
It  will  be  well  to  keep  the  variometer 
well  away  from  the  tuning  coil  (L1-L2) 
so  that  there  will  be  no  coupling  between 
the  two  units,  and  for  the  best  results 
it  is  better  to  incline  the  coupler  at  a 
considerable  angle  so  that  the  axis  of  the 
coupler  does  not  coincide  with  the  axis 
of  the  variometer  stator. 

Condenser  (CI)  should  be  of  the  ver- 
nier type,  capacity  0.0005  m.  f.  (23 
plates).  This  form  of  coupler  is  very 
sharp  and  a  vernier  arrangement  of  some 
kind  is  therefore  highly  desirable.  For 
the  tubes  ordinarily  used,  the  grid  con- 
denser (CG)  should  be  of  the  mica  type 
with  a  capacity  of  0.00025  mf.  While  a 
variable  grid  leak  is  the  best,  a  1.0 
megohm  fixed  leak  will  generally  be  very 
satisfactory.  The  bypass  condenser 
(Kl)  has  a  capacity  of  0.002  mf.  and  is 
effective  in  reducing  the  impedance  of 
the  plate  circuit,  for  the  phones  (PH) 
and  the  "B"  battery  both  introduce  a 
high  resistance  to  the  radio  frequency 
currents  in  this  circuit.  The  "B"  battery 
voltage  may  range  from  16  to  45  volts, 
but  with  the  average  tube  it  is  likely  that 
22.5  volts  will  be  perfectly  satisfactory. 

Picking  the  Tubes 

A  NY  type  of  standard  tube  will  give 
-'*•  satisfactory  results,  ranging  from 
the  WD-12  to  the  UV-201A  or  the  UV- 
200.  The  latter  is  somewhat  more  sen- 
sitive as  a  detector  and  will  give  good 
results  on  voltages  not  much  exceeding 
22.5  volts.  This  tube  is  sharper  and 
more  critical  than  the  hard  tubes.  The 
battery  "A"  depends  upon  the  tube 
used.  For  the  WD-12,  a  single  1.5  volt 
cell  of  dry  battery  is  used.  For  the  UV- 
199  we  use  three  dry  cells  in  series,  giving 
a  total  of  4.5  volts,  while  for  the  UV-200 
and  UV-201-A  a  six  volt  storage  battery 
is  best. 

It  is  best  to  leave  the  aerial  and  ground 
wires  (1)  and  (2)  connected  temporarily 
until  the  set  is  completed  and  can  be 
tuned  in.  Now  connect  the  aerial  (AN) 
and  the  ground  connection  (GND)  to 
(a)  and  (b)  alternately,  until  the  best 
results  are  obtained.  When  this  is  deter- 
mined, the  connection  of  the  primary 
(LI)  can  be  soldered  in  permanently. 
There  is  one  connection  that  is  best 
and  experiments  alone  can  determine 
this. 

As  with  all  regenerative  circuits,  this 
circuit  will  radiate  from  the  aerial  if 
not  carefully  handled,  but  owing  to  the 
small  ratio  between  the  turns  on  coils 
(LI)  and  (L2)  this  effect  is  not  as  bad  as 


The  Magazine  of  the  Hour  45 

with  the  majority  of  circuits  of  this 
nature.  It  is  nowhere  near  as  bad  as  a 
single  circuit  tuner  and  is  better  than 
the  majority  of  vario-coupler  types 
having  a  greater  number  of  turns  on  the 
primary.  The  looser  the  coupling  be- 
tween (LI)  and  (L2)  the  less  trouble 
there  will  be  from  local  "razzing"  and 
interference. 

Do  not  let  your  tube  whistle  or  howl 
in  tuning,  and  when  you  tune  into  a  wave, 
tune  in  sharply.  Don't  get  in  on  the 
fuzzy  edge  of  a  wave.  Don't  keep  your 
tubes  heated  up  to  bright  incandescence. 
If  you  obey  these  instructions,  you  will 
not  cause  much  disturbance  in  the  neigh- 
borhood. 

From  those  of  our  readers  who  have 
tried  out  this  circuit  from  sketches  mailed 
to  them  before  this  article  was  written, 
we  have  had  remarkable  reports  on  its 
selectivity  and  range.  It  is  a  simple, 
stable  circuit  without  any  gew-gaws, 
and  should  appeal  to  the  beginner  in 
radio. 


TJBRE  again  we  have  the  conventional 
-*--*-  Armstrong,  which  seems  to  have  sur- 
vived all  the  fads  and  foibles  of  the  game. 
Circuits  have  come  and  gone,  but  this  form 
seems  to  have  stuck  about  as  well  as  the 
crystal.  In  a  way  this  is  the  same  with 
the  basic  circuits;  they  survive  while  the 
adaptations  and  substitutes  are  gradually 
eliminated  from  the  field. 

Of  course,  any  of  the  regenerative  sets 
coupled  to  an  antenna  will  emit  a  strong 
or  a  weak  wave  when  the  tube  is  oscillat- 
ing, the  strength  of  the  antenna  emission 
depending  upon  the  amount  of  coupling 
between  the  antenna  circuit  and  the 
secondary.  If  the  coupling  is  close, 
stronger  emission  will  be  noted  than  if  the 
coupling  is  kept  very  loose.  By  the  same 
token  an  increase  of  selectivity  is  noted 
whenever  the  coupling  is  loosened  more 
and  more  until  a  point  has  been  reached 
where  the  feeble  energy  in  the  now  dis- 
tant antenna  coil  will  not  induce  current 
in  the  secondary. 

For  those  who  wish  to  follow  he 
"golden  rule"  of  radio,  a  step  of  radio 
frequency  ahead  of  any  regenerative  cir- 
cuit, if  properly  arranged,  will  eliminate 
the  emission  from  such  regenerative  cir- 
cuits which  emission  has  been  the  bane 
of  existence  of  countless  thousands  of 
cliff  dwellers  in  the  thickly  populated 
areas. 


Symposium 

on  methods  of  doing 

away   with 

Oscillation 

In  the  September  issue  of  Radio 
Age  fans  will  find  an  article  deal- 
ing with  all  the  known  methods  of 
preventing  oscillation.  Such  an 
article  will  be  an  invaluable  aid  to 
those  experimenters  who  are 
troubled  with  undesired  oscillations . 


(r,  >  ^  ^5, 


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48 


The  Magazine  of  the  Hour 


RADIO  AGE  for  August,    1925 


A  Regenerative  Reflex  Circuit 

By  JOHN  B.  RATHBUN 


REFLEX  circuit  experimenters  are 
divided  into  two  camps.  First, 
those  who  are  adherents  of  the 
crvstal  detector,  commonly  known  as 
the  "Tube  Conservationist  _  Party,"  and 
second,  those  who  believe  in  the  use  of 
the  standard  three-element  tube  as  a 
detector,  and  derisively  called  the  "Howl 
Hounds." 

There  are  arguments  in  favor  of  both 
methods,  but  when  it  comes  down  to  the 
final  analvsis,  it  is  not  so  easy  to  give  an 
opinion  as  to  the  merits  of  either  side. 
In  fact,  I  am  very  glad  I  am  not  in  a 
position  to  take  a  stand  one  way  or  the 
other  and  have  declared  a  condition  of 
neutrality  so  far  as  these  columns  go. 

There  are  those  who  go  so  far  as  to 
state  that  a  reflex  circuit  never  functions 
properly  until  there  is  at  least  some  re- 
generation in  the  radio  frequency  stage, 
and  if  this  is  the  case,  why  not  carry  out 
the  regenerative  idea  throughout  and 
dispense  with  the  crystal?  The  other 
party  to  the  argument  claims  clearer 
reception,  but  when  you  come  right  down 
to  the  bottom  of  the  matter,  the  principal 
objective  is  the  elimination  of  the  de- 
tector tube  and  conservation  of  -  the 
battery  current.  So  it  goes.  As  reflex 
circuits  with  crystal  detectors  have  been 
presented  time  and  time  again  in  RADIO 
AGE,  I  am  going  to  hand  you  a  circuit 
this  time  which  employs  a  three  element 
tube  detector  and  which  works  this  de- 
tector to  the  limit  of  its  capabilities; 
that  is,  the  detector  tube  will  be  made 
regenerative  so  as  to  squeeze  out  the  last 
drop  of  blood  remaining  in  it. 

Advantages  as  Detector 

ALWAYS  remembering  that  I  am 
neutral  (?)  I  will  start  the  ball  rolling 
by  stating  the  following  advantages 
claimed  for  the  tube  as  a  detector.  (1) 
A  standard  detector  tube  is _  capable  of 
considerable  amplification  within  itself, 
while  a  crystal  detector  cannot  amplify. 
(2)  A  tube  detector  can  be  made  re- 
generative, which  adds  still  further  to 
the  range  and  signal  strength.  (3)  The 
use  of  a  tube  detector  eliminates  "cat- 
whisker  punching"  from  the  game  of 
radio  hide-and-seek,  and  this  is  truly  an 
advantage.  (4)  Properly  installed,  a 
tube  tends  to  stabilize  oscillations  in  the 
radio  frequency  circuit  (Perhaps).  _  (5) 
That  the  detector  tube  is  so  efficient 
when  regenerative  that  it  gives  just  as 
much  volume  as  one  reflexed  tube  with 
a  crvstal;  therefore  there  is  no  real  tube 
or  battery  economy  when  a  crystal  is 
used.  In  other  words,  one  two-tube  set 
with  a  tube  detector  will  give  just  as  good 
performance  as  two  reflexed  stages  with 
a  crystal  detector, 'so  what  is  the  use  of 
the  latter?  (6)  That  a  crystal  detector  is 
not  a  perfect  rectifier  as  so  often  claimed, 
and  that  it  introduces  just  as  much 
distortion  and  noise  as  an  improperly 
adjusted  tube  detector  if  not  more. 
There  you  are;  choose  for  yourself. 

While  all  of  the  above  statements  are 
academically  correct,  it  is  not  always 
so  easy  to  make  them  work  out  in  prac- 
tice. I  have  seen  some  tube  detector 
reflexes  which  were  wonders,  and  then 
there  were  others  which  were  far  from 
having  tnis  distinction.  I  have  seen  two- 
tube  reflexes  (with  a  detector  tube)  which 
would  put  a  three  tube  and  crystal  de- 
►»rtor  outfit  to  shame,  both  as  to  clarity 


Getting  the  Most 
From   Your  Detector 


and  range,  and  then  I  have  seen  the 
reverse.  It  depends  a  good  deal  upon 
who  builds  the  circuit  and  how  it  is  put 
up.  I  have  seen  both  circuits  howl  with 
considerable  vigor,  and  the  tube  detector 
has  nothing  on  the  crystal  when  the 
latter  is  out  of  adjustment. 

It  might  be  well. to  remark  at  this  point 
that  a  soft  gas  detector  tube  seems  to  be 
more  effective  in  stabilizing  the  circuit 
than  a  hard  tube,  so  a  soft  tube  should 
be  used  as  the  detector  when  possible. 
Probably  one  of  the  best  tubes  from  this 
standpoint  is  the  "sodion"  tube,  which 
really  does  cut  down  the  oscillating 
tendency  to  a  marked  degree.  Then  do 
you  remember  the  little  Welsh  (501-D) 
tubes  with  the  filament  wrapped  around 
the  outside?  These  were  quite  good 
detectors  for  this  sort  of  circuit,  but  they 
lacked  the  sensitivity  of  the  sodions  and 
the  volume  was  less.  These  tubes  were 
not  oscillators  and  could  not  be  made 
regenerative,  but  they  were  far  more 
effective  than  a  crystal  and  were  much 
quieter. 

The  Circuit  Itself 

NOW  we  come  to  the  actual  circuit 
which  is  illustrated  by  the  accom- 
panying blueprints,  Figs.  1,  2,  and  3, 
which  are  respectively  the  picture  dia- 
gram, the  conventional  symbolic  diagram 
and  the  isometric  view.  These  pictures 
and  diagrams  are  clear  enough  for  the 
class  of  amateurs  I  am  appealing  to  with- 
out the  use  of  extensive  description,  for 
I  believe  that  this  job  should  be  tackled 
only  by  those  who  have  had  previous 
experience  in  building  reflex  circuits. 
It  is  not  so  difficult,  but  it  does  need  that 
experience  by  which  we  can  make  ad- 
justments by  the  sound  of  the  disturb- 
ance. Some  of  the  bypass  condensers 
are  likely  to  be  rather  critical,  and  with 
some  makes  of  transformers,  it  may  be 
necessary  to  change  the  values  of  the 
units  from  those  given  here. 

Tube  (Tl)  is  the  amplifier  tube  which 
amplifies  at  both  radio  and  audio  fre- 
quencies, and  therefore  this  must  be  a 
hard  tube  similar  to  the  UV-199  or 
UV-201A.  Tube  (T2)  is  the  detector 
tube  and  can  be  anything  that  we  may 
choose  to  use  in  the  tube  line.  Either 
a  hard  or  soft  tube  can  be  used  as  a  de- 
tector with  the  preference  in  favor  of  a 
gas-filled  sodion  tvpe.  The  rheostats 
(Rl)  and  (Rl)  must  be  adapted  to  the 
tubes  used,  and  if  controls  are  to  be  at  a 
minimum,  an  amperite  can  be  used  in 
the  filament  circuit  (Rl)  of  the  amplifier 
(Tl),  but  a  rheostat  must  be  always  used 
with  (T2)  as  the  filament  adjustment 
for  this  tube  is  rather  critical.  Just  as  a 
suggestion  as  to  how  an  automatic  fila- 
ment control  can  be  used  with  an  ampli- 
fier tube,  I  have  indicated  an  amperite 
at  (Rl)  in  place  of  the  more  usual  rheo- 
stat, but  the  rheostat  can  be  substituted 
if  desired.  An  automatic  filament  con- 
trol gives  us  just  one  less  adjustment 
to  bother  with,  and  when  once  right,  it 
remains  right. 

At  (L1-L2)  we  have  the  usual  aperiodic 


coupler  consisting  of  about  15  turns  on 
the  primary  coil  (LI)  and  from  55  to  60 
turns  on  the  secondary  coil  (L2).  The 
coils  are  separated  by  about  5-8  inch  for 
selectivity  and  are  wound  on  a  three 
inch  diameter  tube  with  No.  26  D.  S.  C. 
wire.  The  secondary  is  tuned  by  the 
0.0005  mf  variable  vernier  condenser 
(CI).      This  concludes  the   tuning   unit. 

The  output  of  the  amplifier  tube  (Tl) 
passes  through  the  primary  of  the  radio 
frequency  transformer  (RFT),  and  the 
secondary  of  this  transformer  forms  the 
detector  circuit  of  the  detector  tube 
(T2).  We  can  have  either  an  untuned 
transformer  at  this  point  or  an  air-core 
transformer  of  the  neutrodyne  type  with 
a  condenser  tuned  secondary,  but  for 
the  sake  of  simplicity  in  the  controls 
(RFT)  is  shown  of  the  untuned  type 
which  will  give  good  results  on  the  aver- 
age broadcasting  wavelength  range  of 
200  to  600  meters.  A  tuned  transformer 
gives  us  slightly  more  amplification,  but 
it  runs  up  our  controls  to  a  total  of  three, 
and  this  is  not  always  desirable  in  a  set 
of  this  kind. 

As  shown,  regeneration  in  the  detector 
tube  circuit  is  had  by  the  plate  variometer 
(VA)  which  tunes  the  plate  of  the  de- 
tector into  resonance  with  the  grid  cir- 
cuit. This  not  only  increases  the  range 
and  volume  but  it  also  helps  in  obtaining 
selectivity.  In  place  of  the  variometer 
we  can  also  use  a  "tuned  impedance" 
in  the  plate  circuit  consisting  of  a  0.0005 
mf  variable  condenser  with  a  50  turn 
honeycomb  coil.  This  is  for  the  benefit 
of  those  readers  who  are  not  provided 
with  a  variometer,  but  the  results  will 
be  about  the  same  in  either  case.  If  it  is 
desired,  the  tube  (T2)  can  be  made  non- 
regenerative  with  the  variometer  or  tuned 
impedance  omitted  altogether,  and  while 
the  amplification  will  not  be  as  gieat 
this  way,  yet  it  will  be  considerably 
greater    than    with    a    crystal    detector. 

An  audio  frequency  transformer  (AT-1) 
with  a  ratio  of  from  5-1  to  6-1,  is  used 
for  coupling  the  detector  stage  output 
with  the  amplifier  input.  This  is  of  the 
usual  iron  core  type  and  needs  little 
further  comment.  Both  the  primary 
and  secondaries  of  the  transformers  are 
bypassed  by  the  fixed  condensers  (Kl) 
and  (K2).  These  will  probably  work 
out  at  0.002  mf,  but  in  some  cases  the 
transformer  characteristics  are  such  that 
they  can  be  eliminated  altogether.  The 
usual  grid  condenser  (GC)  of  0.00025  mf 
is  used  in  the  grid  circuit  of  the  detector 
tube,  and  a  one  megohm  grid  leak  (GL) 
is  connected  across  the  grid  condenser. 
As  the  detector  tube  is  not  in  the  aerial 
circuit,  a  higher  grid  leak  value  can  be 
used  than  when  the  detector  is  in  the 
forward  position  and  there  will  be  no 
trouble    with    oscillations   and  radiation. 

From  45  to  90  volts  of  "B"  battery 
can  be  used  on  the  amplifier  tube  (Tl), 
but  the  plate  voltage  of  the  detector  tube 
depends  upon  the  type  of  tube  employed 
at  (T2).  If  a  soft  detector  tube  of  the 
UV-200  type  is  used  for  (T2)  we  cannot 
have  more  than  22.5  volts  at  this  point, 
and  as  a  rule  it  is  not  advisable  to  have 
more  than  45  volts  with  any  detector 
(T2)  as  higher  voltages  give  greater 
tendency  toward  squealing  and  oscilla- 
tions. To  provide  for  the  use  of  two 
plate  voltages  for  the  detector  and  ampli- 
fier, a  detector  tap  is  shown  at  (DB). 


Sin**? 


8 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


51 


A  Three-Tube  Neutrodyne 

By  JOHN  B.  RATHBUN 


PROBABLY  the  most  popular  multi- 
tube  circuit  of  the  present  time  is 
the  tuned  radio  frequency  type, 
of  which  the  neutrodyne  is  the  most 
prominent  example.  In  fact,  the  neutro- 
dyne was  one  of  the  first  radio  receivers 
employing  more  than  three  tubes  which 
became  popular  with  the  broadcast 
listener  and  therefore  stands  alone  as 
being  the  representative  long  range 
circuit,  at  least  in  the  minds  of  the  aver- 
age home  builder.  This  popularity  led 
to  the  development  of  a  long  series  of 
"dynes"  which  bear  more  or  less  re- 
semblance to  the  original  neutrodyne 
and  all  of  which  are  members  of  the 
tuned  radio  frequency  family. 

Tuned  RF  Arguments 

In  a  tuned  radio  frequency  circuit 
the  distinguishing  feature  is  the  employ- 
ment of  tuned  transformers  (air  core 
type)  in  the  radio  frequency  stages. 
Each  radio  frequency  transformer  is 
individually  tuned  to  wave  length  by 
means  of  a  variable  condenser  connected 
across  the  secondary  coil  and  by  this 
means  the  maximum  amplification  or 
"peak"  is  obtained  on  all  wavelengths 
within  the  range  of  the  condenser  and 
coils.  Further,  the  tuning  of  the  inde- 
pendent stages  very  greatly  increases 
the  selectivity,  since  each  transformer 
is  an  additional  tuning  coupler  which 
augments  and  corrects  the  selectivity 
of  the  first  antenna  coupler.  With  two 
stages  of  radio  frequency  amplification, 
we  have  three  tuning  controls,  the  an- 
tenna coupler  condenser  and  the  two 
variable  condensers  used  in  connection 
with  the  two  radio  transformers.  Should 
the  wave  of  an  undesired  station  succeed 
in  passing  the  antenna  coupler,  it  will 
be  eliminated  in  either  the  first  or  second 
transformer  of  the  succeeding  tuned 
radio  transformers. 

Because  of  the  condenser  effect  be- 
tween  the   grid   and   plate   of   the   tube, 


Clear  Tone  Assured 
by  a  Crystal  Detector 


we  cannot  attain  maximum  amplifica- 
tion in  the  radio  stages  unless  the  feed- 
back through  this  capacity  is  offset  by 
some  external  device.  Starting  from  the 
antenna  end  of  the  circuit,  we  find  that 
some  of  the  radio  energy  will  feed  straight 
through  the  internal  capacity  of  the  tube 
without  any  amplification.  Starting 
at  the  output  or  plate  end  of  the  radio 
stages  we  can  see  that  some  of  the  plate 
current  is  fed  back  to  the  antenna  through 
the  tube  capacity  and  thus  produces 
regeneration  with  its  annoying  noises 
and  re-radiations  from  the  aerial.  When 
regeneration  in  the  radio  stages  occurs 
in  this  way,  we  cannot  carry  the  electron 


In  this  article  you  find  the  orig- 
inal neutrodyne,  the  patents  on 
which  are  chiefly  held  by  Prof. 
Hazeltine.  This  type  of  a  receiver 
long  held  sway,  and  still  does  to  a 
large  extent,  but  the  chief  difficulty 
seemed  to  be  in  getting  proper 
neutralization   at   all    wavelengths. 

With  the  newer  forms  of  induct- 
ance winding,  this  trouble  was 
gradually  lessened,  until  today  by 
proper  design  it  is  almost  possible 
to  arrange  tuned  r.  f.  circuits  with- 
out means  of  neutralization.  We 
say  "almost"  for  the  sake  of  con- 
servatism, though  there  are  many 
who  claim  total  elimination  of 
necessity  for  neutralization  by  the 
type  of  inductances  now  in  use. 


emission  to  the  point  required  without 
also  producing  troublesome  audio  oscilla- 
tions or  squealing,  and  this  of  course 
limits   the   possible   amplification. 

A/TANY  AMATEURS  who  have  wished 
-L»-l  to  work  the  neutrodyne  circuit 
have  been  held  back  by  the  expense  of 
the  usual  five  tube  standard  set.  It  is 
for  this  reason  that  the  writer  has  worked 
out  a  three  tube  neutrodyne  which  will 
give  many  of  the  advantages  of  the  more 
elaborate  circuit  with  only  a  slightly 
reduced  output  and  range.  A  crystal 
detector  is  substituted  for  the  more  usual 
detector  tube  and  only  one  stage  of  audio 
frequency  amplification  is  employed, 
thus  doing  away  with  two  of  the  tubes. 

Fig.  1  is  a  picture  diagram  of  the  three 
tube  neutrodyne,  where  it  will  be  seen 
that  we  have  two  radio  frequency  stages, 
a  crystal  detector,  and  one  audio  stage. 
This  will  insure  very  good  distance  re- 
ception and  loud  speaket  volume  on  all 
but  the  more  distant  stations.  The 
crystal  avoids  the  noises  of  the  detector 
tube,  thus  giving  a  very  pure,  natural 
tone  that  is  unapproached  by  the  stand- 
ard five  tube  set.  Further,  when  properly 
adjusted  it  will  not  squeal  nor  howl  under 
any  tuning  conditions. 

All  Tubes  Amplify 

In  Fig.  1  the  two  radio  frequency  tubes 
are  at  (Tl)  and  (T2),  the  crystal  detector 
is  at  (CD),  and  the  audio  tube  at  (T3). 
All  tube  filaments  are  controlled  by  the 
single  rheostat  (R),  the  resistance  of 
which  depends  upon  the  type  of  tubes 
used,  and  as  this  carries  the  current  for 
all  tubes  the  resistance  must  be  some- 
what lower  than  when  a  single  rheostat 
is  used  for  each  tube.  It  must  be  borne 
in  mind  that  all  of  the  tubes  are  ampli- 
fiers such  as  the  UV-201A,  C-301A, 
UV-199  or  C-299  and  that  soft  detector 
tubes  will  not  give  the  necessary  ampli- 
fication. 

(Continued  on  Page  56) 


Blueprints  for  Three-Tube  Neutrodyne  on  Pages  Following 


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RADIO  AGE  for  August  1925 


The  Magazine  of  the  Hour 


A  Simple  But  Effective 
Neutrodyne 

(Continued  from  page  55) 
In  the  aerial  circuit  (ANT)  we  have 
the  fixed  coupler  (RFT-1)  with  the 
aperiodic  primary  coil  (1)  and  the  sec- 
ondary coil  (2).  The  secondary  (2)  is 
tuned  to  wavelength  by  the  variable 
condenser  (CI)  while  the  lower  end  of 
the  primary  (1)  is  grounded  to  the  ground 
post  (GND)  and  to  the  (-A)  line.  The 
plate  output  of  tube  (Tl)  is  fed  into  the 
primary  coil  (1)  of  the  radio  frequency 
transformer  (RFT-2)  where  it  induces 
a  current  of  higher  voltage  in  the  second- 
ary coil  (2)  of  RFT-2.  The  outer  end 
of  the  secondary  (2)  is  connected  to  the 
grid  of  the  second  tube  (T2)  where  the 
next  radio  amplification  takes  place. 
The  secondary  of  (RFT-2)  is  tuned  to 
wavelength  by  the  variable  condenser 
(C2)  which  is  the  second  control.  In 
the  same  way,  the  output  of  the  tube 
(T2)  is  fed  into  the  crystal  detector  cir- 
cuit (CD)  by  means  of  the  third  radio 
transformer  (RFT-3).  The  crystal  de- 
tector (CD)  rectifies  the  radio  current 
into  the  modulated  audio  frequency 
current. 

.  \  LL  THREE  units  (RFT-1),  (RFT-2) 
■^*-  and  (RFT-3)  are  standard  air  core 
radio  frequency  transformers  commonly 
known  as  standard  "Neutrodyne  Trans- 
formers," and  it  is  far  better  to  buy  these 
transformers  ready  made  than  to  attempt 
making  them  at  home.  Unless  properly 
made,  such  transformers  will  greatly 
reduce  the  effectiveness  of  the  circuit 
and  cause  trouble  in  tuning.  In  the 
diagram  of  Fig.  1,  the  transformers  are 
shown  laid  flat  down  in  a  horizontal 
position  so  that  the  connections  can  be 
more  easily  seen,  but  actually  they  are 
tilted  up  at  an  angle  of  about  60  degrees 
with  the  horizontal  so  that  there  will  be 
no  coupling  between  the  adjacent  stages. 
It  is  of  the  greatest  importance  that  we 
avoid  having  the  magnetic  flux  from  one 
transformer  feedback  into  the  following 
transformer,  hence,  the  arrangement 
must  be  made  as  in  Fig.  2  where  the 
transformers  are  shown  tilted  up  at  an 
angle  of  60  degrees  with  the  baseboard. 

As  shown  by  Fig.  3,  the  center  to  center 
spacing  between  the  transformers  and 
condensers  is  5  1-2",  and  the  transformers 
should  not  be  closer  than  this  if  maximum 
results  are  to  be  obtained.  With  this 
spacing  we  can  get  the  apparatus  on  a 
7x18"  panel  without  difficulty  but  if 
we  consider  adding  a  second  stage  of 
audio  in  the  future  it  would  be  better 
to  use  a  7x21 "  or  7x24"  panel. 

Returning  to  Fig.  1,  we  see  the  neutral- 
ing  condensers  (NC)  used  for  neutraliz- 
ing the  internal  capacity  of  the  tubes. 
At  one  end  they  are  connected  to  the 
grids  (G)  of  the  tubes  while  at  the  other 
end  a  connection  is  made  to  an  inter- 
mediate tap  in  the  secondary  of  the 
transformers.  By  adjusting  these  con- 
densers (NC)  we  can  completely  offset 
the  internal  capacity  so  that  maximum 
amplification  is  attained.  The  neutraliz- 
ing condensers  (NC)  should  be  purchased 
ready  made,  and  as  they  can  be  obtained 


at  a  comparatively  low  cost  we  will  not 
enter  into  their  construction. 

Tuning  Condensers 

The  secondary  tuning  condensers  (CI), 
(C2),  (C3),  should  be  a  reliable  make  of 
variable  condenser.  Plain  condensers 
are  used  and  verniers  are  not  necessary. 
The  majority  of  the  commercial  neutro- 
dyne transformers  on  the  market  require 
a  condenser  having  a  maximum  capacity 
of  0.00035  mf  of  what  is  commonly  known 
as  a  17  plate  condenser.  Usually,  a  23 
plate  condenser  is  too  large  for  this 
purpose,  and  makes  the  tuning  un- 
necessarily critical  and  difficult.  The 
condensers  can  be  connected  to  the 
transformer  secondaries  by  the  brackets 
shown  or  else  by  wires  when  the  trans- 
formers are  of  the  type  which  are  fastened 
to  the  floor. 


USE  THE  ORIGINAL 
RADIO  AGE 
BLUEPRINTS 

On  Pages  53  and  54 

to  Make  This 

Three  Tube  Neutrodyne 


In  connecting  the  condensers  to  the 
secondary  coil  of  the  transfromers  we 
should  take  particular  care  to  have  the 
stator  or  stationary  plates  connected 
to  the  wire  which  runs  to  the  grid  of  the 
tube,  as  shown  in  the  diagram.  The 
rotor  or  movable  plates  should  be  con- 
nected to  (-A)  and  ground.  If  this  is 
not  followed  out,  then  we  will  be  sure 
to  have  trouble  with  body  capacity. 
The  outside  turn  of  the  secondary  coil 
(to  the  right),  the  stator  of  the  condenser 
and  the  grid  wire  must  be  connected 
together  for  the  best  results.  This  is 
clearly  shown  in  the  diagram  and  should 
be  followed  out  carefully  by  the  builder. 

Any  Ratio  Possible 

At  (AT)  we  have  the  usual  iron  core 
audio  frequency  transformer  for  the 
audio  stage.  Almost  any  ration  can  be 
used  with  slightly  varying  results.  With 
a  ratio  of  3-1  or  5-1  we  obtain  very  clear 
amplification  with  a  slight  decrease  in 
volume.  With  a  10-1  ration  we  have  a 
somewhat  greater  amplification  but  with 
slightly  increased  distortion.  A  ratio 
of  5-1  probably  is  the  best  compromise 
but  this  is  not  exactly  the  case  with  all 
makes  of  transformers.  In  any  case 
there  will  be  less  distortion  and  noise 
with  a  crystal  detector  circuit  than  when 
a  detector  tube  is  used,  and  therefore 
we  can  probably  use  a  higher  ratio  with 
this  circuit  than  would  be  permissible 
with  a  circuit  employing  a  detector  tube. 

A  0.001  mf.  fixed  condenser  (Kl)  is 
connected  across  the  primary  (P'-B') 
of  the  transformer  to  bypass  the  radio 
frequency  component.  No  jacks  are 
used  for  the  detector  and  final  stages, 
since  they  introduce  complications  into 


the  circuit.  We  have  only  three  tubes 
and  the  small  additional  current  taken 
by  the  final  tube  doesn't  make  it  practical 
to  introduce  jacks  at  this  point.  A  fixed 
bypass  condenser  (K2)  bypasses  the 
radio  current  across  the  phones  and 
"B"  battery.  The  value  of  this  con- 
denser is  not  critical  and  may  range  from 
0.0025  mf.  to  0.006  mf. 

Battery  and  Voltages 

TPO  produce  the  maximum  range  and 
-*-  volume,  we  will  require  a  90  voli 
"B"  battery  for  supplying  the  plate 
current.  This  is  connected  between  the 
(  — B)  and  (  +  B)  battery  binding  posts. 
The  audio  amplification  will  be  made 
somewhat  greater  if  we  introduce  a  4.5 
vole  "C"  battery  between  the  secondary 
transformer  post  (G')  and  the  grid  (G) 
of  the  tube  (T3).  Full  details  of  this 
arrangement  were  shown  on  Data  sheets 
JJ-9-25  and  JJ-9-26  of  the  September 
RADIO  AGE.  The  installation  in  Fig. 
1  of  data  sheet  JJ-9-26  shows  the  in- 
stallation exactly  as  it  would  be  made. 
Be  sure  that  the  negative  (-)  post  is 
connected  to  the  (G)  post  of  the  socket. 

After  the  circuit  has  been  wired  up 
according  to  the  diagram  in  Fig.  1,  with 
the  apparatus  located  as  in  the  isometric 
view  of  Fig.  3,  we  can  connect  the  bat- 
teries, insert  the  tubes,  and  then  make 
the  neutralizing  adjustments.  With 
the  tubes  lighted  up  to  normal  brilliancy 
we  can  tune  in  some  local  station  by 
means  of  the  variable  condensers  until 
we  obtain  maximum  volume.  Now  note 
the  position  of  the  dials  on  the  condensers, 
and  after  loosening  the  dial,  set  the  screws 
and  turn  them  until  the  same  number 
on  each  dial  comes  exactly  opposite  to 
its  stationary  pointer.  This  will  save 
much  time  in  tuning,  as  we  are  now  able 
to  get  all  three  condensers  in  exact  agree- 
ment by  turning  to  the  same  number 
on  each   dial. 

With  everything  running  at  full  pitch, 
remove  the  first  radio  tube  (Tl)  from 
its  socket  and  place  a  piece  of  paper 
across  the  "A"  battery  contacts  so  that 
the  tube  will  not  light  when  replaced 
in  the  socket.  With  this  tube  in  place, 
but  not  lighted,  see  if  you  still  hear  the 
local  station  with  the  rest  of  the  tubes 
at  normal  brilliancy.  If  you  do,  then 
adjust  the  first  neutralizing  condenser 
(NC)  until  you  can  no  longer  hear  the 
signals.  With  this  accomplished,  take 
tube  (T2)  out  of  its  socket,  place  a  piece 
of  paper  across  the  battery  springs  as 
before,  so  that  the  filament  of  tube  (T2) 
will  not  light.  With  the  other  tubes 
burning,  try  again  to  see  if  any  signals 
are  being  heard  through  the  capacity  of 
the  dead  tube.  If  signals  are  still  heard 
with  (T2)  dark,  adjust  the  second 
neutralizing  condenser  (NC)  until  signals 
cease  or  are  reduced  to  a  minimum. 

The  set  is  now  only  partly  neutralized 
at  best  and  further  adjustments  of  the 
neutralizers  (NC)  will  probably  be  neces- 
sary until  the  best  tone  and  volume,  and 
the  best  all  around  reception  is  had. 
There  should  be  no  squealing  or  howling 
and  the  "tweet-tweet"  of  the  carrier 
wave  should  be  very  faint  when  tuning 
into  a  station 


lisl II  Isl  1 

■GsBtunniiBiHinS 

'-.- 

* 

RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


55 


A  3-Tube  Portable  Reflex 

By  JOHN  B.  RATHBUN 


TO  BE  truly  portable,  according  to 
my  idea,  means  that  a  receiving 
set  should  be  easily  carried  about 
from  place  to  place  without  seriously 
straining  its  owner's  physique,  and  at 
the  same  time  it  should  be  so  compact 
that  it  will  not  take  up  any  more  room 
than  necessary  in  a  trunk.  There  are 
portables  and  portables,  but  the  absolute 
zero  in  portability  is  the  set  made  up  in 
a  traveler's  sample  case  which  weighs 
about  100  pounds  and  occupies  about 
fifty  per  cent  of  the  trunk  space.  On  the 
other  extreme  is  the  freak  midget  set 
which  has  been  variously  fitted  into  pill 
boxes,  fountain  pens  and  pickle  bottles, 
and  which  has  absolutely  no  purpose  in 
life  except  to  exhibit  the  make's  in- 
genuity. The  real  portable  should  have 
a  good  range  and  sufficient  volume  to 
operate  a  loud  speaker,  and  yet  at  the 
same  time  should  not  take  up  a  great 
deal  more  space  than  a  camera,  even 
when  fully  equipped  with  batteries. 

No  really  practicable  portable  has 
been  turned  out  with  less  than  three 
tubes,  for  it  is  impossible  to  operate 
a  loud  speaker  satisfactorily  with  less 
tubes  on  anything  but  local  stations. 
For  this  reason  I  will  assume  a  three 
tube  set  from  the  beginning  and  will 
build  up  all  the  other  data  about  this 
premise.  Whether  this  is  to  be  a  regen- 
erative, radio  frequency  or  reflex  still 
remains  to  be  seen,  but  as  the  maximum 
volume  is  to  be  obtained  from  a  minimum 
number  of  tubes  and  batteries,  I  have 
strong  leanings  for  the  reflex  type.  The 
reflex  circuit  is  not  always  the  greatest 
distance  getter,  but  what  it  does  get, 
it  gets  good  and  loud. 

Batteries  Consume  Space 

PROBABLY  the  most  important  item 
-*•  in  a  portable  is  that  of  the  batteries, 
for  the  batteries  weigh  more  and  take 
up  more  space  than  the  rest  of  the  equip- 


Reversed  Capacity 
Feedback  Cuts  Out 
Free    Oscillations 


ment.  Our  current  supply  system  must 
be  reduced  to  the  lowest  possible  limit 
even  at  some  sacrifice  in  the  life  of  the 
batteries.  If  the  batteries  stand  up  for 
a  month  while  traveling  about,  it  is  gen- 
erally considered  satisfactory  for  vaca- 
tion tours.  At  home,  we  can  substitute 
larger  batteries  installed' outside  the  set, 
but  in  touring,  the  space  and  weight  arc 
the   principal   items.      With   this   idea   in 


"EVERYTHING  I  NEED 
IN  RADIO" 

"I  bought  a  copy  of  the  RADIO 
AGE  ANNUAL  for  1925  and  I 
found  that  everything  I  wanted 
to  know  about  radio,  from  crystal 
sets  to  complicated  multi-tubers, 
was  contained  between  its  two 
covers,"  wrote  an  enthusiastic 
beginner. 

"I  never  knew  so  much  could  be 
contained  in  one  book  without 
crowding  or  omitting  necessary 
details.  But  you  haven't  left  a 
thing  out  of  the  ANNUAL  for 
1925." 

Letters  such  as  the  above  are 
sent  to  us  every  day,  voicing  sin- 
cere appreciation  of  the  ANNUAL 
for  1925,  the  most  complete  radio 
hookup  book  ever  printed.  And 
the  price  for  the  120  pages  of 
technical  "nuggets"  is  but  ONE 
DOLLAR,  postpaid. 

Send  your  order  now  while 
our  supply  of  the  limited  first 
edition  lasts. 


mind,  we  will  study  the  battery  situa- 
tion and  the  proper  tubes  to  go  with 
these  batteries. 

Dry  Cells  Used 

Storage  batteries  are  out  of  the  ques- 
tion, of  course,  hence  only  dry  cells  are 
available  for  the  filament  and  plate 
current.  This  means  that  the  tubes 
must  either  be  of  the  WD-12  or  the  UV- 
199  type,  which  are  specially  designed 
for  dry  cell  service.  They  do  not  give 
the  volume  of  the  201A  power  tubes 
used  with  storage  batteries,  but  they 
give  excellent  results  if  properly  handled. 

The  WD-11  and  WD-12  are  the  same 
tube  with  the  exception  of  the  base. 
The  base  of  the  WD-11  is  a  special  small 
size,  while  the  WD-12  fits  in  a  standard 
socket.  Both  tubes  operate  on  the  1.5 
volts  produced  by  a  single  dry  cell  and 
take  0.25  ampere  per  tube.  Each  tube 
therefore  takes  1.5x0.25  =0.375  watt, 
or  3-8  watt.  One  No.  6  dry  cell  is  pro- 
vided for  each  tube,  which  can  be  con- 
nected independently  to  each  tube  of  a 
multi-tube  set  or  to  a  multiple  connected 
battery  with  as  many  cells  as  tubes. 
As  0.25  ampere  is  the  rated  discharge 
rate  for  a  No.  6  cell,  it  is  not  possible 
to  use  a  smaller  battery. 

Next  come  the  UV-199  or  the  C-299 
tubes,  which  require  3.0  volts  at  the  fila- 
ment, and  which  take  only  0.06  ampere 
of  current.  As  the  voltage  of  a  battery 
falls  off  with  use,  we  must  use  three  dry 
cells  in  series,  which  gives  us  a  total  of 
4.5  with  a  fresh  battery.  This  excess 
is  taken  care  of  by  a  30  to  40-ohm  rheo- 
stat, which  permits  the  use  of  a  battery 
between  the  limits  of  4.5  volts  and  3.0 
volts,  the  battery  being  discarded  when 
the  voltage  drops  to  the  latter  point. 
The  power  taken  is  therefore:  4.5x0.06  = 
0.27  watt,  very  much  less  power  than  is 
required  with  the  WD-12. 

(Turn  to  page  56) 


Blueprints  of  the  3-Tube  Portable  Reflex  on  Two  Pages  Following 


BOQOOOQOODOOOQOOOPaOOPQOeflCBgea 


RADIO  AGE  is  the  only  radio  magazine  on  the  market  to  originate  and  maintain 
the  blueprint  form  of  printing  hookups  in  its  columns. 

The  popularity  of  such  a  process  is  shown  by  the  countless  letters  from  fans, 
many  of  whom  would  rather  work  from  a  blueprint  than  the  best  black-and-white 
drawing  available. 

Every  month  you  will  find  in  RADIO  AGE  a  set  of  blueprints  together  with  a 
descriptive  article  by  John  B.  Rathbun  on  how  to  construct  a  certain  type  of  set. 
By  becoming  a  subscriber  of  RADIO  AGE,  you  have  a  steady  stream  of  accurate  and 
workable  blueprints  coming  into  your  home;  a  handy  reference  for  the  future, 
or  a  necessity  for  the  present  in  the  making  of  a  good  receiver. 


»PQOaBOQQQQgaOQCQOQQOOgCBBOBOQOOflgflQBOOBQOBOBQae 


56 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


(Continue!  from  page  55) 
Qualities  of  "199"  Tube 

NOT  only  is  the  power  loss  with  the 
UV-199  tube,  but  the  amplification 
is  greater  than  with  the  YVD-12,  and  the 
199  is  much  more  satisfactory  in  the 
amplication  of  radio  frequency  currents 
in  reflex  sets.  In  fact,  the  199  comes 
next  to  the  201A  tube  in  regard  to  am- 
plication and  only  takes  one-quarter 
of  the  current.  Three  No.  6  "A"  batteries 
will  operate  three  199  tubes  for  a  long 
time,  for  the  discharge  rate  is  only 
3x0.06  =  0.18  ampere,  or  less  than  a 
single  WD-12  tube.  The  199  is  the  ideal 
tube  for  a  portable  set  from  many  stand- 
points, and  takes  up  a  minimum  of  room. 

As  the  rating  of  a  No.  6  dry  cell  is  0.25 
ampere  for  filament  lighting,  this  size 
of  cell  will  operate  three  199  tubes  for  a 
very  long  period,  much  longer,  in  fact, 
than  would  be  absolutely  necessary  with 
a  portable  receiver.  For  this  reason, 
we  can  use  a  smaller  filament  battery 
with  satisfactory  results,  and  if  the  set 
is  not  used  for  too  long  a  period,  a  4.5 
volt  C  battery  can  be  used  for  each  tube. 
As  the  C  battery  takes  up  much  less 
space  and  weighs  much  less  than  a  No. 
6  cell,  we  can  use  a  4.5  volt  C  for  each 
tube  or  a  total  of  three  C  batteries  in 
all.  For  home  use,  where  less  frequent 
replacements  are  desirable,  we  can  use 
a  larger  external  battery — a  storage 
battery  if  necessary. 

An  alternative  will  be  to  use  two  C 
batteries  in  parallel  for  each  tube.  This 
will  give  longer  life  than  the  singles  as 
connected  above,  but  will  take  less  space 
than  three  No.  6  cells.  The  following 
table    will    give    the    comparative    sizes: 

NO.  OF     SIZE  OF  SPACE 

CELLS      CELLS  OCCUPIED 

3  No.  6  5"x5"x6.5  =  162.5  cubic  in. 
3  C  4.1"x3"x4"  =49.5  cubic  in. 
6     C      4.1"x6"x4"   =  99.0  cubic  in. 

In  effect,  the  three  C  batteries  will  be 
connected  in  parallel  through  a  switch, 
and  w-e  will  use  the  C  batteries,  as  we 
wish  to  get  the  smallest  possible  set. 
If  longer  service  from  No.  6  cells  is 
required,  then  the  only  change  necessary 
will  be  to  use  a  single  group  of  three  cell 
in  series  of  the  No.  6  type,  and  to  corre- 
spondingly enlarge  the  battery  com- 
partment of  the  set. 

The  Hookup  in  Detail 

In  general,  the  "Junior  Reflex"  is  a 
regenerative  reflex  using  a  tube  detector 
with  a  tickler  coil  feed-back  and  equipped 
with  one  additional  stage  of  straight 
audio  frequency  amplification.  This 
arrangement  gives  us  one  stage  of  radio 
frequency  amplification,  a  regenerative 
stage,  and  two  stages  of  autio  amplifica- 
tion. Enough  for  three  tubes.  A  short, 
temporary  aerial  of  from  40  to  60  feet 
will  be  all  that  is  ordinarily  required, 
either  of  the  indoor  or  outdoor  type, 
and  I  have  had  good  service  with  a  30 
foot  indoor  aerial  run  around  the  picture 
moulding  of  the  room.  So  far  as  possible, 
small  or  miniature  parts  are  used  to 
economize  space,  and  it  is  surprising  how 
much  apparatus  we  can  get  into  a  small 
cabinet  when  we  make  up  our  mind  to 
concentrate  our  efforts  to  this  end. 


A  special  method  of  avoiding  oscilla- 
tions by  means  of  a  reversed  capacity 
feed-back  is  applied  to  the  radio  fre- 
quency tube,  which  has  proved  effective 
in  all  the  cases  experimented  upon  by 
the  writer.  The  plate  current  is  fed  back 
into  the  primary  of  the  tuning  coil 
through  a  very  small  variable  condenser 
in  such  a  way  that  it  opposes  the  free 
oscillation  tendency  of  the  first  tube. 
It  is  a  simple  application  of  the  reversed 
feed-back  system  without  the  necessity 
of  a  tickler  coil.  As  the  suppression  of 
free  oscillations  is  one  of  the  most  difficult 
propositions   met    with    by   the   amateur 


MATERIALS  FOR   "JUNIOR 
PORTABLE" 


6-1 

B— 4    "B  *    batteries,    22.5    volt    blocka.      Small    size 
(1200  m.  h.). 

C1-C2 — 2    Vernier    variable    condensers.    0.00035    mf 
17  plate). 

C3 — 1  Equalizing  variable  condenser. 
0  ililuoti  mf. 

*-C" — Small  bias  battery. 

D — 1  Bakelite  panel  10   xS  3-4"x3-16" 

E— 1  Bakelite  tube  shell  4"x6  l-8"xl-S". 

F — 6  Marked  binding  posts. 

GL— 1  Grid  leak  (adjustable  or  fixed).  1.0  to  2.0  mee- 
ohms. 

Jl—  1  Single  circuit  jack.       ' 

Kl — 1  Fixed  condenser,  mica  ins.  type  0.001  mf. 

K2 — 1  Fixed  condenser,  mica  ins.  type  0.002  mf. 

K3 — 1  Fixed  condenser  with  leak  lugs  0.00025  mf. 

K4 — I  Fixed  condenser  mica  ins   type  0.00025  mf. 

R1-R3 — 2  Amperites  for  fila.  control  (199,  4.5  volts). 

R2 — 1  Filament  rheostat,  vernier,  40  ohm  type. 

RFT-1 — 1   Standard   air  core   R.  F.   transform  neutro- 
dyne  type. 

RFT-2 — 1  Bakelite  tube.  2  1-i"  diam.  3"  long. 

RFT-2 — 1-4    lb.    silk    covered    magnet    wire    No     26 
D.  S.  C. 

S — 4  small  brass  shelf  or  support  angles. 

12'  Bus  wire.  No.  14.  tinned  copper. 

1'    Rosin    core    solder. 

1'  Spaghetti. 

25  Miscellaneous  machine  screws. 

U — 2  Condenser  dials  (If  not  with  con.)  3""  Diam. 

SW — 1  Battery  cutout  switch.  Standard. 

T1-T2-T3— 3  UV-199  tubes. 

V — 3  "199"  tube  sockets,  absorb,  base. 

W — 4  Condenser  angles  for  holding  coils  on  condensers. 

X — 8'   Flexible   fixture   cord   for   battery   connections. 
No.  18. 

Y — 1  Special  cabinet  (Complete). 

1  Phone  plug. 

60'  Annunciator  wire,   wax  cotton   or   No.    18   flexible 


in  the  construction  of  a  reflex  circuit, 
he  will  find  this  a  most  important  point. 

Fig.  1A  is  a  schematic  diagram  of  the 
"Junior  Portable,"  showing  the  three 
tubes,  the  transformers,  and  all  con- 
nections. The  tube  (Tl)  is  the  reflexed 
radio  frequency  and  audio  frequency 
tube;  tube  (T2)  is  the  detector,  and 
(T3)  is  the  straight  audio  frequency 
amplifier.  All  radio  frequency  stages 
are  tuned  by  variable  condensers  so  that 
the  maximum  amplification  peak  is 
attained,  and  at  this  same  time  this  is  a 
valuable  aid  to  the  selectivity  of  the  set. 
The  second  tuning  coil  or  radio  frequency 
transformer  is  of  a  special  type,  as  it 
contains  three  coils  which  act  respectively 
as  the  primary,  secondary  and  tickler 
coils.  Only  two  dials  are  required  for 
the  tuning  operation  proper,  the  regenera- 
tion being  controlled  by  the  detector 
rheostat,  a  method  that  is  entirely  prac- 
ticable with  a  vernier  rheostat,  and  which 
greatly  simplifies  the  construction  and 
tuning. 

At  RFT1  we  have  the  usual  aperiodic 
tuning  coil  with  the  primary  (P)  and 
the  secondary  (S)  which  is  tuned  by  the 
17  plate  (0.00035  mf)  variable  condenser 
(CI)  connected  across  the  secondary 
in  the  conventional  manner.  A  detail 
of  this  tuning  unit  is  shown  in  Fig.  IB, 
which  shows  the  principal  dimensions. 
There  are  58  turns  on  the  secondary 
and    12   turns   on    the    primary   coil    (P), 


with  a  separation  between  the  two  coils 
of  approximately  1-2  inch.  The  wire  is 
No.  26  D.  S.  C.  magnet  wire. 

Condenser  for  Suppression 
/"OSCILLATIONS  in  the  radio  fre- 
^-'  quency  circuit  are  suppressed  by 
the  very  small  variable  condenser  (C) 
connected  between  the  primary  coil 
(on  the  aerial  side)  and  the  plate  of  the 
first  tube  (Tl).  This  is  a  condenser 
such  as  the  "Chelton  Midget"  or  the 
"Amplex"  neutralizing  condenser,  having 
a  maximum  capacity  of  from  0.000025 
to  0.00006  mf.  This  is  somewhat  critical 
on  most  sets,  hence  the  condenser  (C3) 
is  represented  by  a  dial  on  the  front  of 
the  panel.  When  properly  adjusted 
the  first  stage  can  be  cleared  up  quickly 
and  easily  by  this  simple  adjustment. 

The  output  of  the  first  tube  passes 
through  the  primary  (P)  of  the  special 
transformer  (RFT-2)  which  transfers 
the  radio  frequency  current  to  the  de- 
tector tube  (T2).  This  coil  (P)  is  located 
about  1-4  inch  from  the  end  of  the  sec- 
ondary coil  (S),  and  at  the  other  end  of 
(S)  is  the  tickler  coil  (T)  provided  for 
regeneration  in  the  detector  stage.  All 
three  coils  are  in  fixed  relation  on  the 
same  tube,  and  the  detector  circuit  is 
tuned  to  wavelength  by  the  variable 
condenser  (C2)  connected  across  the 
secondary  coil  (S).  The  tickler  (T)  has 
about  25  turns,  the  secondary  (S)  has 
58  turns  and  the  primary  (P)  is  a  12 
turn  coil.  The  general  details  of  this 
coil  or  transformer  are  shown  by  Fig. 
1C,  but  it  may  be  found  necessary  to 
give  a  few  more  or  less  turns  on  (T)  until 
the  proper  regeneration  is  obtained  with 
the  vernier  rheostat  (R2)  turned  to  the 
"half-on"  position. 

Need  Accurate  Rheostat 

As  the  current  flowing  through  the 
coil  (T)  is  almost  entirely  dependent 
upon  the  filament  emission,  and  hence 
the  rheostat  adjustment,  a  very  accurate 
rheostat  will  be  required.  A  40-ohm 
rheostat  will  be  found  about  right  at 
this  point  for  the  proper  control  of  regen- 
eration by  the  filament  emission  system. 
If  the  tube  has  to  be  turned  up  bright 
for  the  regenerative  effect,  increase  the 
number  of  turns  on  (T)  until  it  starts 
to  "flop  over"  with  the  rheostat  turned 
about  half  way  on.  The  regulating 
resistance  for  the  radio  reflex  tube  (Tl) 
is  an  Amperite  shown  at  (Rl),  and  a 
second  Amperite  is  at  (R3)  for  the  auto- 
matic control  of  the  amplifier  filaments. 
The  amplifier  tubes  (T1-T3)  are  not 
critical,  but  the  detector  tube  (T2)  is 
very  critical  so  that  a  rheostat  must  be 
used  instead  of  an  Amperite  at  this  point. 

The  detector  tube  circuit  is  a  conven- 
tional feed-back  circuit  and  has  the  usual 
grid  condenser  (K3)  and  grid  leak  (GL)' 
The  grid  leak  is  from  1  to  2  megohms, 
and  the  condenser  (K3)  is  probably  best 
at  0.00025  mf.  A  bypass  condenser 
(fixed)  is  placed  at  (K2)  which  is  of  assist- 
ance in  reducing  the  R.  F.  resistance  of 
the  detector  plate  circuit.  The  value 
may  range  from  0.001  mf  to  0.002  mf, 
depending  upon  conditions  in  the  circuit. 
The  circuit  tuning  condenser  (C2)  has 
a  capacity  of  0.00035  mf.,  so  that  (CI) 
and  (C2)  will  "log"  well  together. 

As  is  usual,  the  output  of  the  detector 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


57 


tube  is  reflexed  back  to  the  first  tube 
(Tl)  by  means  of  the  audio  frequency 
transformer  (AFT-1),  the  latter  being 
in  the  grid  return  circuit  of  the  first 
stage.  This  can  be  any  make  of  trans- 
former having  a  ratio  varying  from  4-1 
to  6-1,  but  as  we  wish  to  gain  every 
inch  possible,  I  have  shown  the  miniature 
Premier  Hegehog  transformer  in  the 
picture  diagrams.  In  some  cases,  a 
0.00025  mf  fixed  condenser  (K4)  im- 
proves results  when  connected  across 
the  secondary  coil  of  (AFT-1),  and  again, 
this  seems  to  have  but  little  effect.  It 
seems  to  be  a  matter  of  experiment  with 
each  individual  set  to  determine  whether 
(K4)  should  be  used.  Its  effect  is  prin- 
cipally on  DX  rather  than  on  volume 
with  local  stations,  so  that  we  should  try 
for  distance  in  making  this  adjustment 
rather  than  to  experiment  for  volume 
alone. 

The  output  of  the  reflexed  tube  (Tl) 
now  passes  to  the  primary  coil  of  the 
second  audio  transformer  (AFT-2),  and 
this  latter  transformer  is  a  part  of  a 
straight  audio  stage  that  is  not  reflexed. 
Connections  are  made  to  (T3)  in  the  usual 
standard  manner,  and  the  total  output 
of  all  three  tubes  passes  out  through 
the  output  jack  (Jl)  to  the  phones  or 
loud  speaker.  This  is  not  a  complicated 
circuit  to  hook  up,  but  it  requires  some 
readjustments  as  with  any  reflex  circuit, 
particularly  in  regard  to  the  values  of 
the  bypass  condensers. 

For  the  smallest  portable  set,  three 
4.5  volt  "C"  batteries  are  used  for  the 
filament  current  as  at  (A1-A2-A3),  the 
cells  being  in  parallel  and  connected 
to  the  circuit  through  the  battery  cutout 
switch  marked  (SW). 

22.5  Volts  for  Detector 

T)LATE  or  "B"  battery  connections 
-•-  are  tapped  according  to  the  require- 
ments of  the  various  stages.  A  voltage 
of  22.5  volts  generally  proves  best  for 
the  detector  circuit  under  all  around 
conditions,  although  45  volts  may  give 
greater  volume  and  selectivity  on  local 
stations.  A  potential  of  45  volts  is  most 
effective  on  the  radio  frequency  tubes 
on  distance,  hence  a  45  volt  tap  is  indi- 
cated for  this  stage.  The  audio  stage 
requires  90  volts  for  the  best  performance, 
and  67  volts  gives  nearly  as  good  results 
with  one  less  block  of  "B"  battery.  The 
set  can  also  be  operated  withj45  volts  on 
the  audio  stage,  but  with  greatly  diminish- 
ed volume  on  all  stations.  I  do  not 
recommend  placing  the  full  90  volts  on 
the  radio  frequency  stage,  and  never  on 
the  detector  stage,  and  after  experiment- 
ing extensively  I  find  that  the  best  all 
around  results  will  be  found  with  the 
plate  battery  connections  as  indicated. 

Four  small  B  batteries  (90  volts  total) 
can  be  used  for  this  set  and  will  last  most 
of  the  season.  The  smallest  B  batteries 
are  the  450  milliampere-hour  cells 
which  measure  2"  wide,  3-3-8"  long  and 
2-9-16"  high.  The  next  largest  size  take 
up  very  little  more  space  and  give  much . 
longer  service.  This  is  the  1200  milli- 
ampere-hour size  which  is  2-9-16"  wide, 
4-1-6"  long  and  2-3-4"  high.  The  latter 
size  are  the   more  practicable,   especially 


with  three  tubes,  and  are  shown  in  the 
assembly  diagram.  With  three  tubes 
kicking  out  from  10  to  12  milliamperes, 
the  450  m.  a.  h.  type  does  not  last  very 
long  before  the  voltage  runs  down  and 
the  volume  falls  off. 

In  the  table  on  page  38  is  listed  all  of 
the  material  required  for  building  this 
set,  each  item  in  the  list  being  preceded 
by  a  letter  corresponding  to  the  letters 
on  the  diagram.  All  of  these  parts  are 
standard  and  the  majority  are  built 
by  a  number  of  radio  concerns  so  that 
it  will  not  be  difficult  to  pick  up  all  of  the 
parts  at  your  dealer's.  The  only  special 
parts  are  the  cabinet,  which  must  be 
built  to  fit  the  job  at  hand,  and  the  tun- 
ing coils  and  RF  transformer,  which  can 
easily  be  wound  up  at  home.  A  neutro- 
former  or  tuning  unit  can  be  purchased 
for  use  in  place  of  RFT-1,  but  RFT-2 
is  special  and  is  not  stocked. 


Outdoors  or 

Indoors — You 

Will  Find  All  Your 

Radio  Needs 

Satisfied  In 

RADIO   AGE 

Every  Month. 


Another  Blueprint 

Hookup  In  September 

RADIO  AGE— Out  Aug.  15 


Fig.  2  shows  all  of  the  parts  connected 
up  in  "picture"  form  for  the  benefit  of 
the  novice  who  does  not  understand  con- 
ventional or  symbolic  diagrams.  Either 
Fig.  1  or  Fig.  2  can  be  used  in  making 
the  actual  connections,  for  both  show  the 
same  circuit  and  the  parts  are  lettered 
with  corresponding  letters. 

Fig.  3  is  a  rear  elevation  of  the  set  with 
the  back  panel  removed  and  shows  how 
the  parts  are  assembled,  ready  for  wiring. 
The  three  tubes  and  sockets  are  mounted 
on  the  top  of  the  shelf  (E)  while  the  audio 
transformers  are  hung  underneath.  This 
not  only  saves  room  but  it  also  shortens 
and  simplifies  the  wiring.  Of  course, 
machine  screws  must  be  used  for  this 
assembly  instead  of  the  more  usual  wood 
screws,  as  all  parts  are  fastened  to  bake- 
lite.  The  shelf  is  attached  to  the  panel 
by  means  of  the  small  brass  angle  brack- 
ets (S)  which  can  be  made  at  home  or 
purchased  at  almost  any  radio  store. 

I  wish  to  call  your  attention  to  the 
fact  that  the  two  radio  frequency  trans- 
formers or  tuning  coils  (RFT-1)  and 
(RFT-2)  must  be  placed  at  right  angles 
to  one  another,  as  shown,  to  prevent 
coupling  back  between  stages  and  to  pre- 
vent oscillations  being  set  up  by  induc- 
tion. The  coils  are  supported  by  brass 
lug  connections  to  the  terminals  of  the 
variable  condensers  so  that  their  weight 
is  substantially  supported.  It  should  be 
particularly  noted  that  the  stator  or  sta- 


Blueprints  of  the  3 -Tube  Portable  Reflex  on  Pages  Following 


tionary  plates  of  the  variable  condensers 
(C1-C2-C3)  connect  to  the  grids  of  the 
tubes  to  prevent  the  body  capacity  effect 
from  being  carried  out  to  the  front  of  the 
panel  through  the  shafts  of  the  condensers. 
The  grids  are  at  a  high  potential,  and 
anything  connected  to  the  grids  is  easily 
affected  by  the  capacity  of  the  hand  and 
is  detuned  by  this  capacity  effect. 

All  of  the  batteries  are  carried  in  the 
bottom  of  the  cabinet,  very  closely 
packed  together  to  prevent  movement, 
and  connections  are  made  with  the  cir- 
cuit above  through  the  flexible  cords 
(X).  Connections  are  more  certain  and 
more  easily  made  if  "spade"  type  clips 
are  soldered  to  the  ends  of  these  cords. 
Do  not  use  solid  wire  for  this  purpose 
or  simple  cotton  covered  wire,  as  such 
wire  is  likely  to  short-circuit.  Flexible 
fixture  wire  has  a  rubber  covering  which 
is  further  protected  by  a  cotton  braid, 
making  a  short  circuit  unlikely. 

The  Aerial  Wire 

HP  HE  aerial  wire  can  be  a  temporary 
-"-  affair  run  around  the  picture  moulding 
of  the  room,  strung  up  temporarily  from 
room  to  room,  hung  between  trees  or 
other  supports.  It  is  connected  to  the 
antenna  post  (ANT)  with  the  other  end 
left  free  and  unconnected.  For  indoor 
service  about  60  feet  of  annunciator 
will  be  sufficient  and  no  supporting  in- 
sulators will  be  needed,  as  the  waxed 
cotton  cover  will  be  sufficient  insulation 
when  laid  along  the  plaster  of  the  walls 
or  along  wood  surfaces.  For  outdoor 
work,  or  where  it  is  likely  to  be  damp, 
a  wire  with  rubber  insulation  should  be 
used,  such  as  flexible  fixture  wire  or 
lamp  cord.  Lamp  cord  is  excellent  for 
this  purpose,  as  it  has  a  low  R.  F.  re- 
sistance and  is  sufficiently  flexible  to 
allow  winding  up  in  a  small  coil. 

After  cutting  the  batteries  into  circuit 
by  means  of  the  battery  switch  (SW), 
the  detector  rheostat  (R2)  and  the 
equalizing  condenser  (C3)  are  adjusted 
until  all  whistling  and  howling  stop. 
There  should  be  a  slight  hissing  or  frying 
noise  which  will  indicate  that  the  tubes 
are  functioning,  but  the  adjustments 
should  not  be  much  above  this  point. 
Next,  turn  the  wavelength  adjustment 
condensers  (CI)  and  (C2)  very  slowly 
and  at  about  the  same  rate  of  speed  until 
a  "station  whistle"  or  voice  is  picked  up. 
Juggle  the  condenser  dials  until  the  signal 
is  at  a  maximum,  and  then  manipulate 
the  detector  rheostat  (R2)  just  under 
the  point  where  it  is  about  to  break  down 
into  free  oscillations  and  where  the  sig- 
nal is  at  a  maximum.  Working  the 
detector  rheostat  in  connection  with  the 
condender  (C3)  will  give  the  maximum 
volume. 

Remember  that  (C3)  is  for  the  purpose 
of  checking  oscillations  in  the  radio 
frequency  circuit,  and  that  this  controls 
the  radio  frequency  circuit  in  about  the 
same  way  that  the  detector  rheostat 
controls  the  detector.  Howling  can  be 
checked  by  either  (C3)  or  (R2)  depending 
upon  whether  the  trouble  is  in  the  radio 
frequency  or  detector  circuits. 

The     selectivity     depends     upon     the 
(Turn  to  page  58) 


58 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


Battery  Problem  Easily  Handled 


(Continued  from  page  57) 
distance  of  the  primary  coil  (P)  from  the 
secondary  (S).  The  greater  the  distance 
the  looser  will  be  the  coupling  and  the 
greater  the  selectivity.  This  applies  to 
both  (RFT-1)  and  (RFT-2).  Usually 
the  best  spacing  of  the  coils  is  as  shown 
by  Figs.  IB  and  1C,  but  with  some  types 
of  audio  frequency  transformers,  this 
must  be  increased.  The  wavelength 
range  is  determined  by  the  number  of 
turns  on  the  secondary  coils  (S),  and  as 
shown,  will  cover  a  range  of  from  200 
to  600  meters. 

Fig.  4  is  a  front  e.evation  of  the  panel, 
showing  the  dials  and  other  controls. 
It  is  advisable  to  allow  the  cabinet  to 
project  beyond  the  panel  in  front  for  the 
protection  of  the  dials,  and  to  provide 
a  door  at  this  point,  so  that  the  set  can 
be  completely  closed. 

Trouble   Shooting 

WHEN  the  signals  are  weak  and  the 
selectivity  seems  poor,  the  trouble 
is  usually  due  to  coil  reversal ;  that  is,  the 
various  coils  in  the  tuner  or  transformer 
do  not  bear  the  proper  inductive  relation 
to  one  another.  If,  for  example,  the  prim- 
ary coil  should  be  connected  so  that  it 
produces  a  magnetic  field  that  opposes 
the  field  of  the  secondary  coil,  then  the 
output  will  be  practically  neutralized  and 
there  will  be  little  reception.  It  is  for  this 
reason  that  I  suggest  that  you  connect  up 
all  of  the  primary  coils  permanently  when 
you  wire  the  set,  and  make  temporary 
connections  to  the  secondary  coils  and 
tickler  coil  with  magnet  wire. 

After  you  connect  up  the  set,  you  can 
tune  in,  and  if  results  are  not  satisfactory 


at  the  first  attempt,  try  reversing  the 
connections  to  the  secondary  and  tickler 
one  at  a  time,  until  you  get  the  best 
results.  After  the  best  point  is  found, 
you  can  complete  the  wiring  by  substitut- 
ing soldered  bus  wire  connections  for  the 
temporary  wires.  This  may  save  you  a 
lot  of  work  and  should  be  observed. 

Be  sure  that  the  prongs  of  the  tubes 
are  making  proper  contact  with  the 
springs  in  the  sockets,  and  try  this  out 
before  you  screw  the  sockets  down  into 
place.  A  loose  tube  or  loose  contacts 
mean  all  kinds  of  trouble,  and  trouble 
that  is  difficult  to  remedy  after  the  set  is 
completed  and  in  the  cabinet.  Also 
carefully  examine  the  jack  connections, 
and  make  sure  that  a  projecting  lump  of 
solder  is  not  short-circuiting  the  jack. 
The  lugs  are  very  close  together  and  it  is 
easy  to  short-circuit  at  this  point. 

Use  only  the  small  "midget"  type 
variable  condensers  for  the  transfer  (C3). 
A  standard  condenser,  even  as  small  as  a 
three  plate,  is  much  too  large  to  cover  the 
range  even  with  all  of  the  plates  out  of 
engagement.  The  zero  capacity  of 
standard  condensers  is  very  frequently 
greater  than  the  maximum  capacity 
desired  at  (C3). 

Sometimes  reception  is  improved  by 
connecting  a  0.001  mf  fixed  condenser 
across  the  ends  of  the  jack  (Jl),  and  some- 
times this  has  no  effect  at  all.  It  all 
depends  upon  the  winding  characteristics 
of  the  coils  in  your  phones  and  speaker. 

In  making  battery  connections,  be 
sure  that  the  positive  pole  of  your  "B" 
battery  is  connected  into  circuit  at  the 
point  indicated  in  the  drawings,  that  is, 


the  positive  of  the  "B"  battery  must 
always  go  to  the  plate  directly,  or  to  the 
plate  through  the  tickler  coil  or  trans- 
former primary.  If  this  polarity  is  not 
observed,  the  set  will  be  absolutely  dead 
without  a  hiss  or  grunt  to  be  heard. 

A  biasing  "C"  battery  for  the  grid  of 
the  audio  amplifying  tube  (T3)  can  be 
connected  in  at  (  — C)  and  (  +  C)  as  shown 
just  under  the  audio  transformer  (AFT-2) 
in  Figs.  1—2.  This  will  save  enough  "B" 
battery  current  to  pay  its  way,  but  if  it 
is  not  desired  at  the  present  time,  the 
binding  posts  or  connections  (  — C)  and 
(+C)  can  be  sort  circuits  as  indicated 
by  the  dotted  line  running  between  these 
two  connections.  The  "C"  battery  can 
be  the  smallest  type  of  "C"  battery  or 
else  can  be  a  small  flash  light  battery, 
either  giving  a  total  potential  of  4.5  volts 
on  the  grid  of  the  tube  (T3). 


In  this  article  Mr.  Rathbun  has  made 
up  a  set  that  is  really  portable.  Hereto- 
fore portability  has  been  a  word  and  not 
an  accomplishment,  for  whatever  was 
labelled  portable  was  sure  to  tip  the 
scale  around  the  hundred  pound  mark. 
But  in  this  the  weight  is  kept  down, 
which  alone  should  appeal  to  the  camper 
or  traveler. 

The  future  of  the  portable  does  not 
seem  to  be  in  doubt.  The  set  will  be 
improved  more  and  more  as  time  goes 
on,  so  that  eventually  it  will  be  down  to  a 
small  sized  outfit  that  can  be  readily 
carried  and  which  will  at  the  same  time 
perform  nearly  as  good  as  one  of  the 
larger  sets. 


WeDQOQeOQQQBOB 


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Face  to  Face ! 

in  The  ''What  The  Broadcasters  Are  Doing"  Section  of 

RADIO  AGE 


Intimate,  interesting  sketches  of  the  Radio  Personalities  of  America  are  to  be 
found  in  RADIO  AGE  every  month — presented  in  an  attractive  and  inter- 
esting way.     Fully  illustrated  with  up-to-the-minute  pictures.     Get  acquainted 

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RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


63 


More  Volume  and  Range  with 

A  5-Tube  Radio  Frequency  Set 

By  JOHN  B.  RATHBUN 

SINCE  the  introduction  of  the  five-     ~~ R.  F.  or  audio  amplification.     In  the  most 

tube   neutrodyne   about   two   years  /\      r\PCP\l)PT     tnOt      Vv    1 1 1     part  they  confined  their  inventiveness  to 

ago,   we  have  had  an   almost  end-  contriving  schemes  for  the  elimination  of 

less  stream  of  five-tube  radio  frequency  M  InimtZe      DlStOrtlOn 
dynes     which  testily  to  the  popularity 


of  this  sort  of  radio  receiver.  This 
neutrodyne  was  the  first  really  high 
powered  type  introduced  to  the  general 
public  for  broadcast  reception.  The 
fans  to  this  time  had  been  limited  to  the 
three-tube  regenerative  with  the  con- 
ventional detector  and  two  stages  of 
audio  frequency.  The  addition  of  the 
two  stages  of  radio  frequency  to  the 
detector  in  the  neutrodyne  not  only 
increased  the  range  enormously,  but  also 
very  considerably  added  to  the  selectiv- 
ity, and  I  believe  that  the  selective 
feature  of  the  tuned  radio  frequency 
set  had  as  much  to  do  with  its  promotion 
as  the  increased  range  and  the  possi- 
bility of  coast-to-coast  reception  on  the 
loud  speaker. 

Untuned  radio  frequency  reception 
with  untuned  radio  frequency  coupling 
units  had  proved  somewhat  of  a  fizzle, 
not  only  because  the  maximum  range 
and  signal  strength  were  not  developed 
but  also  for  the  reason  that  such  re- 
ceivers were  hardly  more  selective  than 
the  regenerative  set  of  that  period,  and 
even  two  years  ago  the  question  of  inter- 
ference was  becoming  a  serious  proposi- 
tion. By  tuning  the  transformers  be- 
tween the  radio  frequency  stages,  we 
reach  the  amplification  peak  in  each 
stage  and  also  increase  the  losses  at  a 
number  of  points  so  that  undesired 
stations  could  be  eliminated  with  cer- 
tainty, even  through  strong  local  inter- 
ference. Using  three  tuning  controls 
made  long  distance  reception  possible 
for  the  city  dweller  on  every  night  in 
the  week. 

The  Typical  5-Tube  Set 

USUALLY   the   five-tube   outfits   con- 
sisted   of   two    stages    of   radio    fre- 
quency amplification,  detector,  and  two 


stages  of  transformer  coupled  audio 
stages.  There  was  seldom  any  attempt 
at  regeneration  in  the  detector  tube 
circuit  or  any  other  means  of  amplifica- 
tion outside  of  the  simple  amplifying 
powers  of  the  tubes  themselves.  True, 
the  first  neutrodyne  introduced  by 
Prof.  Hazeltine  was  of  the  reflex  type, 
but  strange  to  say,  little  interest  was 
taken  in  the  reflexed  neutrodyne  until 
a  few  months  ago.  Experimenters  seemed 
content  to  stick  to  straight  radio  fre- 
quency amplification  without  the  assist- 
ance   of   either   regeneration    or    reflexed 


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contriving  schemes  for  the  elimination  of 
oscillations  in  the  radio  frequency  stages. 
For  a  long  time  the  suppression  of 
oscillations  in  the  radio  frequency  stages 
was  a  problem  to  which  many  solutions 
have  since  been  offered.  We  have  the 
well-known  neutralizing  system  intro- 
duced by  Prof.  Hazeltine,  the  reversed 
feed-back  system,  the  potentiometer, 
and  similar  devices,  and  it  is  in  this  part 
of  the  circuit  that  most  five  tube  radio 
frequency  circuits  differ  from  each  other. 
It  would  be  almost  impossible  to  say 
which  of  these  systems  has  proved  the 
most  sensitive  and  efficient,  for  each 
type  has  its  band  of  adherents  who  defy 
any  of  their  opponents  to  show  better 
reception  or  greater  range. 

It  has  long  been  the  belief  of  the 
writer  that  very  marked  improvement 
could  be  made  in  the  five  tube  radio 
frequency  receivers  by  the  introduction 
of  regeneration  in  the  detector  circuit 
or  by  reflexing  certain  of  the  stages  so 
that  some  of  the  tubes  could  be  made  to 
perform  dual  duty.  Shortly  after  the 
introduction  of  the  neutrodyne,  I  made 
several  experiments  in  obtaining  re- 
generation in  the  detector  circuit  by 
means  of  a  variometer  or  tuned  im- 
pedance in  the  plate  circuit,  but  while 
this  increased  the  range  and  signal 
strength  considerably,  it  did  not  meet 
favor  for  the  reason  that  it  introduced 
a  fourth  control,  and  a  rather  critical 
sensitive  control  at  that.  Further, 
regeneration  was  not  always  dependable 
with  neutralized  grids,  and  as  neu- 
tralization held  the  floor  at  that  time  to 
the  exclusion  of  every  other  idea,  the 
matter  was  dropped  for  the  time  being. 

Rheostats  Cause  Trouble 

rpO    ELIMINATE    the    fourth    regen- 

-*-  erative   control,    I    next   tried   several 

(Turn  lo  page  64) 


Blueprints  of  the  Five-Tube  Radio  Frequency  Receiver  on  Pages  Following. 


ant  To  Be 

Affairs^  Read  Radio  Age  Every  Month ! 

For  Radio  news  and  latest  Radio  Hookups,  RADIO  AGE  has  never  been 
"Scooped."  As  soon  as  a  new  and  promising  hookup  has  been  tested  and  found 
efficient,  it  is  presented  to  the  readers  of  RADIO  AGE,  in  a  clear,  concise  manner, 
illustrated  profusely  with  accurate  isometric  and  circuit  diagrams. 

So— Let  Our  Hookups  Be  Your  Guide 


64 


RADIO  AGE /or  August,  1925 


The  Magazine  of  the  Hour 


Results  with  a  Reflexed  Detector 


(Continued  from  page  63) 
regenerative  stunts  in  the  detector  cir- 
cuit such  as  the  fixed  tickler  used  in  the 
Wizard  receiver,  and  the  Ultra-audion 
single  control  method,  both  of  which 
gave  strong  regeneration  and  sensi- 
tivity but  which  made  the  rheostat 
controls  critical  and  difficult  to  manage. 
With  such  circuits,  control  of  the  regen- 
eration is  had  entirely  by  the  rheostatic 
or  filament  emission  method,  and  a 
vernier  rheostat  is  absolutely  essential 
for  the  proper  adjustment.  Unless  it 
was  brought  just  below  the  oscillating 
point,  the  circuit  would  break  out  into 
violent  free  oscillation  with  accom- 
panying howls  and  shrieks.  While  this 
gave  wonderful  results  in  the  hands  of 
an  experienced  operator,  it  certainly 
was  not  a  circuit  to  install  in  the  home 
or   for   the   everyday   broadcast   listener. 

It  seemed  for  a  while  that  the  only 
resort  was  to  reflex  the  detector  circuit 
and  this  is  what  I  finally  accomplished 
after  a  number  of  experiments.  The 
reflexing  of  the  so-called  detector  stage 
or  third  tube  both  increased  the  volume 
and  improved  the  quality  of  the  recep- 
tion, and  from  many  standpoints  was 
an  advance  over  the  regenerative  prin- 
ciple or  the  totally  reflexed  method  by 
which  all  of  the  tubes  were  reflexed. 
Reflexing  the  third  tube  alone  gave  us 
approximately  three  stages  of  radio 
frequency  amplification  with  the  same 
number  of  tubes  ordinarily  used  to  obtain 
two  stages,  and  in  addition  it  added 
about  0.8  of  an  audio  stage.  Further 
audio  amplification  was  then  obtained 
by  two  stages  of  resistance  coupled 
audio,  which  gave  the  total  audio  volume 
without  the  distortion  usually  intro- 
duced by  iron  core  radio  frequency 
transformers. 

Summing  up  the  matter,  we  obtain 
practically  three  stages  of  radio  fre- 
quency amplification  and  the  equivalent 
of  two  audio  frequency  transformer 
coupled  stages  by  five  tubes,  and  with- 
out distortion  or  "razzing"  even  when 
the  tubes  are  being  pushed  to  the  limit. 
The  audio  stages  consist  of  one  trans- 
former coupled  stage  and  two  resistance 
coupled  stages,  which  give  us  a  volume 
slightly  better  than  two  transformer 
stages.  A  crystal  detector  performs  the 
rectification  without  introducing  the 
tube  noises  that  ordinarily  affect  the 
output.  In  short,  it  is  just  like  adding 
two  stages  of  radio  amplification  to  a 
single  reflex  circuit  and  then  increasing 
the  volume  by  the  further  application 
of  two  resistance  coupled   stages. 

The  Circuit  Layout 

TN  FIG.  1  we  have  the  layout  shown 
^  by  a  schematic  diagram  and  in  Fig. 
2  the  same  circuit  is  given  in  "picture" 
form,  which  not  only  shows  the  wiring 
in  simplified  form,  but  also  suggests 
the  arrangement  of  the  apparatus  behind 
the  panel.  Fig.  3  is  the  front  elevation 
of  the  panel  with  the  control  dials  and 
knobs  located. 

Looking  at  Fig.  1  or  Fig.  2  we  see  the 


usual  first  two  radio  frequency  tubes 
(Tl)  and  (T2),  and  the  three  radio 
frequency  coils  or  transformers,  (RFT-1), 
(RFT-2)  and  (RFT-3)  connected  up  in 
the  usual  way  of  radio  frequency  trans- 
formers. The  transformers  are  tuned 
by  the  17  plate  (0.00035  mf)  variable 
condensers  (CI),  (C2)  and  (C3)  con- 
nected across  the  secondary  coils  of  the 
transformers.  There  is  little  to  say 
about  the  transformers  except  that  they 
are    of    the    conventional    type    used    in 


BILL 

OF  MATERIALS 

FOR  THE  SET 

MARK 

NO.  OF 

(LETTER) 

PIECES     NAME  OF  ITEMS      SIZE 

A 

1 

Filament   "A"   Battery,  Stor- 
age   type 6   Volts 

AT 

1 

Audio      Frequency     Trans- 
former  6-1    Ratio 

B 

2 

45    Volt     Blocks    of     "B" 

Battery         Large . 

C1-C2-C3 

3 

Variable       Condensers 

0.00035    mf     (17    Ph.) 

CD 

1 

Fixed  Crystal  Detector 

•GL1-GL2 

2 

Grid  Leaks 1-2  Megohms 

Jl 

I 

Two  circiut  Jack Standard 

J  2 

1 

Single    Circuit    Jack.    Standard 

Kl 

1 

Fixed  Mica  Condenser  0.006  Mf. 

K2 

1 

Fixed  Mica  Condenser  0.002  Mf. 

K3 

1 

Fixed  Mica  Condenser  0.002  Mf. 

•K.4 

I 

Fixed  Mica  Condenser  0.006  Mf. 

•K5 

1 

Fixed  Mica  Condenser  0.006  Mf. 

K6 

1 

Fixed  Mica  Condenser  0.002  Mf. 

K7 

1 

Fixed  Mica  Condenser  0.500  Mf. 

•N1-N2 

2 

Resistors      or      Coupling 

Resistances    .  .    511,000      Ohms 

PO 

1 

Potentiometer 

400  ohms,  or  200  ohms 

R1-R2     . 

2 

Rheostats        for        filament 

Control 6       Ohms 

RFT-1-2-3 

.   3 

Radio       Frequency      Trans- 
formers,    (Tuned)        Standard 

RFX 

1 

Untuned       Radio       Frequency 
Transformer     200-600   meters 

SW 

1 

Battery      Switch Standard 

S 

5 

Tube       Sockets Standard 

Tl-2-3-4-5 

5 

201A  Amplifier  Tubes  Standard 

VM 

1 

Battery       Voltmeter        (Flush 
Type)                    8     to     10     Volts 

W 

I 

Panel 7"x26"x3-16" 

Marked.    - 

G 

Binding    Posts                     Standard 

X 

1 

Terminal  Strip  (bake- 

lite) I"x7ffx3-16" 

Y 

1 

Bottom       Board       (Wood) 

Z 

I 

Radio  Cabinet 7"x26" 

30' 

Tinned    Copper    Square    Bus 
Wire       No.    14 

6' 

Spaghetti        Standard 

SI) 

Solder       Lugs    Standard 

D 

3 

Dials    and    Knobs    4"    Diameter 

NOTEI     ! 

ten 

s  marked  (*)  can  be  substituted 

for    by    co 

mpl 

coupl.ng     un.ts. 

standard  radio  frequency  circuits,  and 
that  it  is  far  more  desirable  to  purchase 
these  parts  than  to  attempt  making 
them  at  home. 

The  three  tubes  (T1-T2-T3)  are  con- 
trolled by  the  six  ohm  rheostat  (Rl) 
while  the  two  audio  frequency  ampli- 
fying tubes  (T4)  and  (T5)  are  regulated 
by  the  six  ohm  rheostat  (R2).  In  giving 
the  resistance  of  these  rheostats,  I  am 
assuming  that  201A  tubes  are  used, 
because  they  give  better  results  than  the 
dry  cell  type.  If  199  tubes  -are  used, 
then  the  resistance  of  thr  rheostats 
must  be  higher,  say  15  or  20  ohms. 
With  five  tubes,  dry  cell  operation  is 
not  recommended,  for  in  the  end  it  will 
be  far  more  expensive  to  replace  dry 
cells  than  to  purchase  a  storage  battery 
and  recharge  it  from  time  to  time.  Dry 
cell  tubes  do  not  give  the  amplification 
of  the  storage  battery  201A  type. 

Grid  potentials  are  regulated  by  the 
potentiometer  (P9).  While  there  are 
certain  objections  which  can  be  leveled 
at  this  type  of  control,  yet  it  is  the  better 
method  for  the  beginner,  especially 
when  it  is  not  known  what  make  or  type 


of  apparatus  he  intends  to  use.  A  400 
ohm  potentiometer  is  the  best,  but  a  200 
ohm  can  also  be  used,  and  to  reduce  the 
radio  frequency  resistance  in  the  grid 
return  line,  a  fixed  bypass  condenser 
(Kl)  of  0.0006  mf  capacity  is  con- 
nected between  the  slider  and  the  nega- 
tive "A"  post  of  the  potentiometer 
resistance  coil.  The  impedance  of  a  wire 
wound  potentiometer  is  considerable, 
and  unless  the  bypass  condenser  is 
installed,  the  tuning  will  be  upset  at 
every  adjustment  of  (PO). 

Reflexed  Third  Tube 

'T'UBE  (T3)  is  the  tube  ordinarily 
-*-  used  as  the  detector  tube,  but  in  this 
case  it  is  the  tube  of  a  special  reflex 
circuit,  acting  both  as  a  radio  and  audio 
amplifier  at  one  time.  In  fact,  there  is 
no  detector  tube  in  the  circuit  since  the 
major  part  of  the  rectification  is  per- 
formed by  the  crystal  detector  (CD). 
Transformer  (RFT-3)  connects  the  radio 
stages  to  the  reflex  stage  and  the  reflex 
is  tuned  by  the  third  variable  condenser 
(C3).  Note  that  all  of  the  radio  fre- 
quency and  audio  frequency  trans- 
formers are  marked  according  to  the 
connection  posts  as  at  (P),  (  +  B),  (G) 
and  — F),  to  correspond  with  the  mark- 
ings on  the  actual  coils. 

At  (RFX)  is  an  untuned  radio  fre- 
quency transformer  used  for  coupling 
the  plate  circuit  of  (T3)  with  the  crystal 
detector  and  the  audio  transformer 
(AT).  The  latter  is  of  the  usual  iron 
core  type,  bypassed  on  both  the  primary 
and  secondary  sides  by  the  fixed  bypass 
condensers  (K2)  and  (K3).  Ordinarily 
the  capacity  of  these  condensers  is 
0.0015  mf  to  0.002  mf,  but  much  depends 
upon  the  type  of  audio  transformer 
used.  In  some  cases  it  will  be  found 
advisable  to  omit  (K3)  altogether  when 
there  is  much  distributed  capacity  in 
the  primary  vvinding. 

On  carefully  examining  the  circuit 
of  tube  (T3)  you  will  see  that  it  is  a 
simple  single  tube  reflex  circuit  giving 
the  equivalent  of  one  stage  of  radio 
and  one  stage  of  audio  amplification, 
so  that  up  to  and  including  (T3)  we 
have  three  radio  and  one  audio  stage  on 
three  tubes.  This  alone  will  give  good 
results,  but  for  the  proper  loud  speaker 
volume  under  all  ordinary  conditions, 
it  was  considered  advisable  to  add  the 
two  resistance  coupled  stages  as  shown 
by  tubes  (T4)  and  (T5). 

By  plugging  in  at  jack  (Jl)  we  obtain 
the  output  of  three  radio  and  one  audio 
stage.  By  plugging  in  at  the  jack  (J2) 
we  obtain  three  radio  and  about  2.6 
audio  stages. 

A  typical  resistance  audio  coupling 
is  made  for  the  tubes  (T4)  and  (T5). 
The  fixed  condensers  (K4)  and  (K5) 
of  0.006  mf  capacity  are  the  coupling 
devices  in  the  grid  lines,  while  the  re- 
sistors (Nl)  and  (N2)  are  non-inductive 
resistances  of  from  48,000  to  50,000 
ohms.  Both  of  the  resistors  are  con- 
nected between  the  positive  "B"  (+B) 
and  the  plate  (P)  of  the  tube,  and  it  is 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


65 


Tubes  Do  Dual  Duty  in  This  Set 


the  difference  of  potential  established 
across  these  resistors  that  causes  the 
amplification.  The  grid  leaks  (GL1) 
and  (GL2)  are  of  one  megohm  to  two 
megohms  capacity  and  are  connected 
between  the  grids  and  ( — A)  just  as 
with  any  grid  leak.  Such  resistors 
introduce  no  distortion  into  the  circuit, 
and  when  worked  in  connection  with 
one  transformer  coupled  stage  as  at 
(AT),  we  obtain  both  volume  and  purity 
of  tone.  The  ratio  of  (AT)  should  be 
from  1  to  i  but  no  higher. 

The  resistors  (N1-N2)  can  be  obtained 
from  a  number  of  RADIO  AGE  adver- 
tisers, either  as  separate  units  or  as 
assembled  units  containing  the  fixed 
condensers,  resistor  and  leaks  all  in 
one  compact  mounting. 

Fig.  IA  at  the  bottom  of  the  circuit 
drawing  shows  the  method  of  connecting 
up  the  resistance  coupling  units  in  com- 
pact form  when  the  resistors  and  leaks 
and  condensers  are  purchased  separately 
and  assembled  by  the  builder  of  the  set. 
Spring  clips  can  be  obtained  for  mounting 
the  resistors  and  grids  just  as  tubular 
grid  leaks  are  mounted 

Bypass  condensers  such  as  (K6)  of 
0.002  mf  capacity  and  (K7)  of  0.5  mf 
capacity  are  frequently  of  advantage 
in  reducing  the  resistance  offered  to  the 
radio  frequency  current  by  the  "B" 
battery  and  the  impedance  of  the  output 
circuit,  particularly  after  the  "B"  bat- 
teries become  old  and  dried  out.  In 
some  cases  and  using  certain  materials 
in  the  circuit,  these  bypasses  work  a 
great  improvement,  while  under  other 
conditions  their  effect  is  unnoticeable. 
However,  the  set  will  perform  better 
and  more  consistently  throughout  the 
life  of  the  "B"  batteries  when  the  by- 
passes are  used  than  when  they  are  not 
installed. 

Materials  Used 

ALMOST  anvof  the  standard  materials 
advertised'  in  RADIO  AGE  can 
be  used  for  this  circuit,  and  as  it  is  against 
our  policy  to  recommend  one  make  of 
apparatus  over  another,  we  cannot 
specify  any  particular  make  in  these 
specifications.  The  only  effect  that  will 
be  caused  by  changing  parts  will  be  on 
the  values  of  the  bypass  condensers, 
and  this  is  always  more  or  less  of  an 
experiment  in  any  case.  However,  the 
bypasses  are  quickly  and  cheaply  shifted 
about,  and  this  should  prove  no  objection 
to  the  user.  Experience  will  show  that 
it  is  very  seldom  that  any  one  value 
of  bypass  will  apply  to  all  conditions  in 
any  circuit. 

In  the  accompanying  list  I  have  given 
the  number  of  parts  needed  and  their 
size,  all  items  being  given  a  letter  cor- 
responding to  the  lettering  on  the  draw- 
ings so  that  their  location  can  be  quickly 
identified. 


ing  can  be  put  on  a  7  "x24 "  bakelite 
or  hard  rubber  panel.  The  inside  dimen- 
sion of  the  cabinet  (depth)  should  be 
at  least  seven  inches  to  accommodate 
the  apparatus.  Care  should  be  taken 
not  to  crowd  the  radio  frequency  trans- 
formers RFT- 1-2-3  too  close  together 
and  the  tubes  should  be  well  oustide 
the  magnetic  field  of  the  transformers 
to  prevent  back  coupling  between  the 
stages.  The  panel  thickness  should  be 
at  least  3-16  inch  so  that  it  will  not  be 
necessary  to  cut  down  screws  or  shorten 
the  shafts. 

In  arranging  the  reflexed  part  of  the 
circuit,  see  that  the  untuned  transformer 
(RFX)  is  placed  as  close  to  the  tube 
(T3)  as  possible,  so  that  the  line  from  the 
post  (G)  on  the  transformer  to  the  (G) 
post  on  the  socket  is  very  short.  This 
is  important.  Again,  keep  (RFX)  well 
away  from  (RFT-3)  and  the  audio  trans- 
former (AT).     If  these  parts  are  so  close 


Are    You    Going    to    Take 

a    Radio    Set    with 

You  on  your 

Vacation  This  Year? 

Watch  this  and 

future  issues  of 

RADIO  AGE 

for    the    latest    in 

Portable    Receiving    Sets 

and  Accessories. 


T 


Assembly  of  Set 

HIS  receiver  will  assemble    easily  on 
a  7"x26"  panel,  and  by  a  little  crowd- 


that  they  are  coupled  by  the  magnetic 
flux,  there  will  be  trouble.  The  crystal 
detector,  which  is  of  the  fixed  or  semi- 
fixed type,  can  be  placed  in  such  a  posi- 
tion that  it  does  not  complicate  the 
wiring,  say  near  the  rear  edge  of  the 
bottom  board.  It  is  not  advisable  to 
put  the  crystal  detector  on  the  panel, 
as  it  is  likely  to  be  knocked  out  of  ad- 
justment every  time  we  handle  the  dials. 

The  coupling  resistances  for  the  audio 
stages  are  small  and  easily  disposed  of 
in  the  arrangement,  and  as  shown  in 
Fig.  2  these  audio  coupling  units  are 
placed  quite  close  to  the  two  audio- 
tubes  (T4)  and  (T5).  All  of  the  arrange- 
ment should  be  made  with  an  eye  to 
simple  wiring  and  simple  connections. 
You  will  not  go  far  wrong  if  you  follow 
the  diagrams  in  every  detail. 

A  voltmeter  (VM)  is  very  useful  in 
a  five  tube  set  for  keeping  the  potential 
constant  across  the  filaments  as  advised 
by  the  makers  of  the  tubes.  As  shown 
in  the  diagrams,  the  voltmeter  registers 
the  potential  across  the  filaments  of  the 
radio  frequency  and  reflex  tubes,  as 
these  tubes  are  the  most  critical  of  the 


series  and  require  the  most  accurate 
adjustment  for  the  filament  control. 
Cutting  the  large  hole  for  the  body  of  the 
voltmeter  is  a  problem  for  the  home 
mechanic  unless  he  has  some  form  of 
"fly-cutter"  for  the  job.  However,  this 
can  be  cut  by  any  machine  shop  or 
radio  store. 

Unless  the  transformers  (RFT)  are 
marked  at  the  connection  post  by  the 
makers,  the  builder  often  has  trouble 
from  "bucking"  or  opposed  coils.  If 
you  do  not  think  that  you  are  getting 
the  proper  volume  or  the  distance,  try 
the  effect  of  reversing  the  connections 
to  the  primary  of  these  coils,  one  by 
one.  In  fact,  it  is  best  to  connect  up  the 
transformers  temporarily  with  small 
insulated  wire  until  you  are  certain  that 
the  polarities  of  the  transformers  are 
correct. 

All  crystals  do  not  work  equally  well 
when  reflexed,  and  for  this  reason  it  is 
best  to  get  some  sort  of  a  crystal  detector 
in  which  the  crystals  can  be  easily 
changed.  With  a  small  stock  of  crystals, 
say  five  or  six,  experiment  until  you  find 
the  best  crystal.  Crystals  do  not  cost 
much  and  they  may  be  the  reason  your 
circuit  is  not  functioning  as  it  should. 
After  the  crystal  detector  is  once  ad- 
justed, and  put  in  an  out-of-the-way 
place  where  it  is  not  likely  to  be  dis- 
turbed, it  will  require  very  little  attention. 

Use  Care  in  Building 

I"  AM  sure  that  if  you  construct  this 
■*■  receiver  with  care  and  use  judgment 
in  the  operation  of  it,  you  will  get  ex- 
ceptionally fine  results.  Its  freedom  from 
distortion  and  extreme  sensitiveness  are 
remarkable.  Stations  from  both  coasts 
have  been  heard  repeatedly  on  the  loud 
speaker  from  my  laboratory  here  in 
Chicago. 

As  I  stated  before,  Professor  Hazel- 
tine's  original  neutrodyne  was  of  the  re- 
flexed type,  but  for  some  reason  little 
interest  was  taken  in  it.  Why  this  should 
be  is  hard  to  explain.  I  suppose  the  rea- 
son is  that  most  fans  were  a  little  bit 
afraid  of  the  reflex  circuits.  We  really 
have  no  reason  to  fear  them,  as  they  are 
quite  simple.  It  just  requires  a  little 
patience  to  get  them  to  operate  correctly. 

Most  of  the  trouble  experienced  seems 
to  be  in  getting  fixed  and  by-pass  con- 
densers of  the  right  capacity.  However, 
these  are  cheap  and  if  the  builder  will 
supply  himself  with  a  selection  of  these, 
he  can  change  the  capacities  of  each  in 
the  different  parts  of  tne  circuit  until  the 
best  results  are  obtained. 

One  of  the  probable  reasons  for  the 
clear  tone  of  this  receiver  is  the  resistance 
coupled  method  of  amplifying  after  the 
detector.  To  those  who  have  not  tried 
this  system  of  increasing  the  signal 
strength  to  loud  speaker  volume,  this 
system  will  be  a  revelation.  All  distortion 
and  transformer  noises  will  be  eliminated. 
If  you  are  undecided  as  to  whether  cr  not 
you  shall  use  resistance  coupling,  my 
advice  to  you  is  to  try  it  by  all  means. 


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Reflex ed  R^dio  Frequency  Se  t 

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70 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


The  6-Tube  '  'Portatron' ' 

By  JOHN  B.  RATHBUN 


COMPACT  portable  radio  receivers, 
having  sufficient  power  to  operate 
on  either  loop  or  flat  top  aerial,  are 
desirable  for  home  use  as  well  as  for 
camping  and  motoring  trips.  Provided 
with  self-contained  batteries,  such  outfits 
can  be  easily  moved  about  from  room  to 
room  in  the  house  or  can  be  carried  to  the 
home  of  a  friend  to  provide  music  for  a 
dance  or  for  other  similar  occasions.  The 
portable  has  a  much  wider  field  of  appli- 
cation than  the  conventional,  cumber- 
some cabinet  with  external  batteries,  and 
should  be  seriously  considered  by  those 
who  desire  a  receiver  of  the  all-round  type. 

For  the  sake  of  simplicity,  such  an 
outfit  should  be  of  the  single  control  type, 
or  should  not  have  more  than  two  controls 
at  the  most.  It  should  have  at  least  two 
radio  frequency  stages  for  distance  and 
for  operation  on  a  loop  aerial,  and  at 
least  two  audio  frequency  stages  for  loud 
speaker  operation.  With  transformer 
coupling  this  means  at  least  five  tubes, 
if  the  tubes  are  not  reflexed,  and  we  must 
therefore  carefully  consider  the  methods 
of  coupling  the  stages  to  conserve  space 
and  to  minimize  the  number  of  controls. 

Dry  batteries  must  be  used  for  the  fila- 
ment "A"  battery,  and  the  type  of  tube 
must  be  such  that  not  more  than  three 
or  four  No.  6  dry  cells  will  be  required. 
This,  of  course,  suggests  the  "199"  tube, 
which  is  ideal  for  a  portable  rig  because  of 
its  low  filament  current  consumption. and 
small  size.  Five  "199"  tubes  will  take 
5  x  0.06  =0.30  ampere  which  is  not  pro- 
hibitive for  dry  cell  service,  and  the  cells 
will  last  for  a  considerable  length  of  time 
on  such  work.  Six  tubes  will  take:  6x0.06 
=  0.36  ampere   which    is    within  reason. 

Transformer  coupling  between  either 
the  radio  frequency  or  audio  frequency 
stages  takes  up  considerable  room.  If 
the  R.  F.  transformers  are  of  the  "tuned" 
type  then  they  must  be  spaced  well  apart 
to  prevent  coupling  back  between  stages, 


_  ling  requires  no  separate  interstage  con- 

(^OntrOlS      Cire      Oimble     |\rols:  hu*  unfortunately,  resistance :  coup 

_  _    l  ling  in  the  radio  frequency  stages  is  onh 


and  Uberation  Uuiet  efficient  °n  i°ns  wavelengths,  say  on 

£ _^ wavelengths   above    1,000   meters.     This 

resistance  coupling  method  will  be  fine 
for  the  audio  stages,  and  is  just  What  will 
be  used  for  the  output,  but  we  will  have 
to  guess  again  in  regard  to  the  coupling 
on  the  R.  F.  end  of  the  hookup.  The 
untuned  or  fixed  radio  frequency  trans- 
former at  once  suggests  itself,  but  for  this 
time  it  must  be  rejected  because  of  the 
space  occupied  and  for  the  reason  that 
such  transformers  are  likely  to  "back- 
couple"  between  stages  if  crowded  to 
gether  as  closely  as  we  intend  to  crowd  the 
stages  of  this  outfit. 


and  this  system  must  therefore  be  dis- 
carded right  at  this  point,  both  for  the 
reason  that  it  takes  up  much  room,  and 
also  for  the  reason  that  a  separate  dial 
control  will  be  required  for  each  radio 
stage  (and  for  the  tuner  unit  in  addition) 
which  will  bring  the  total  number  of 
controls  up  to  three  or  more.  This  is  out 
of  the  question  in  a  portable  outfit;  hence 
we  must  look  farther  for  a  means  of  radio 
frequency  stage  coupling.  We  should 
have  only  a  single  selective  control  for  the 
tuner  unit,  and  no  variable  controls  after 

the   first  stage   that   are   represented   by     '"P  HE  RE  is  only  one  other  coupling  pos- 
j:_i i — i *u_  c — *  „<■  *i — i        -I-    sible    on  the  R.  F.  end,  and  that  is 


dials  or  knobs  on  the  front  of  the  panel. 
Resistance  Coupling 

Resistance     coupling     for     the     radio 
frequency    and    audio    frequency     coup- 


THE  RECEIVER  FOR 
YOUR  NEEDS 

This  Summer's  tendency  will  be 
for  simplified  radio  receivers,  with 
compact  parts  and  ease  of  operat- 
ion and  control.  A  radio]  set 
without  these  characteristics  can- 
not be  called  up-to-date. 

THE  RADIO  AGE  ANNUAL  for 
1925  contains  several  of  these  won- 
der hookups  that  are  easy  to  build, 
easy  to  operate  and  pleasant  to 
hear.  The  latest  in  portable  sets  as 
well  as  the  larger  models  are  all  in 
this  new  ANNUAL,  which  is  yours 
for  $1.  Send  your  remittance  now 
if  you  want  to  have  this  radio 
handbook  with  you  on  your  vaca- 
tion this  year  as  an  ever-ready 
radio  guide. 

$1  while  they  last. 


by  means  of  inductances  of  the  "choke 
coil"  order,  which  are  connected  into  cir- 
cuit just  like  the  resistance  units  of  a 
resistance  coupled  stages.  One  end  of 
the  choke  coil  is  connected  to  the  plate  of 
the  tube,  while  the  other  end  goes  to  the 
(  +  B).  The  connection  between  the 
first  tube  plate  and  the  grid  of  the  follow- 
ing tube  is  made  through  a  fixed  condenser 
just  as  in  the  case  of  the  resistance 
coupling  scheme.  The  choke  coils  must 
have  a  very  much  higher  inductance  than 
commonly  used  with  radio  frequency 
tuning  units.  They  should  consist  of 
several  thousand  turns  of  very  fine  wire. 
The  secondary  coil  of  an  audio  frequency 
transformer  will  be  just  about  right  for 
this  purpose  when  standard  100  Milli- 
henry chokes  cannot  be  obtained.  The 
inductive  value  must  be  sufficient  to  choke 
back  the  high  frequency  plate  current  so 
that  it  will  not  short  circuit  back  through 
the  "B"  battery  connections,  and  at  the 
same  time  the  coil  resistance  should  not 
be  sufficient  to  interfere  with  the  supply 


Blueprints  of  the  Six-Tube  "Portatron"  on  Pages  Following 


K»OQOQDOOffi 


John  B.  Rathbun, 

Originator  of  the  Blueprints 

in  this  remarkable  section, 

writes  exclusively  for 
RADIO  AGE  every  month. 


SPBPOWpOQOBggBOOflOflOOgODBOBBOpflQOOggfleflBea 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


71 


of  continuous  "B"  battery  current  to  the 
plate  of  the  tube.  The  choke  coil  permits 
the  "B"  battery  current  to  pass  to  the 
plate,  but  chokes  back  the  R.  F.  current. 

Radio  Frequency  Amplification 

'T^HE  application  of  the  choke  system 
-■-  to  the  first  three  tubes  will  be  seen 
in  Fig.  1  and  Fig.  2,  where  Fig.  1  is  a 
schematic  diagram  using  symbols,  and 
Fig.  2  is  a  picture  wiring  diagram.  The 
first  will  be  of  more  service  to  the  experi- 
enced builder  in  "doping  out"  the  circuit, 
while  the  latter  will  show  the  novice  how 
the  wiring  connections  are  actually  made 
to  the  parts.  Fig.  3  is  a  front  elevation 
of  the  panel  and  cabinet,  while  Fig.  4  is  a 
rear  elevation  showing  the  parts  assem- 
bled at  the  rear  of  the  panel.  Fig.  3A  is 
a  sectional  view  as  seen  from  one  side  of 
the  assemblage. 

Taking  Figs.  1-2,  we  see  that  an  aperi- 
odic type  coupler  is  used  at  (L1-L2) 
whidh  is  tuned  by  vernier  variable  con- 
denser (CI)  connected  across  the  second- 
ary coil  (L2)  of  the  coupler.  This  can  be 
a  home-made  coupler  such  as  has  been 
described  many  times  in  these  columns; 
it  can  be  a  standard  neutrodyne  trans- 
former or  else  a  standard  adjustable 
aperiodic  tuner.  In  any  event,  the 
primary  coil,  (LI)  is  untuned.  When  the 
usual  flat  top  aerial  is  used,  the  aerial 
lead-in  wire  is  connected  to  (ANT)  and 
the  ground  wire  at  (GND),  a  system  whch 
gives  the  greatest  range  and  signal 
strength.  By  connecting  the  ends  of  a 
loop  aerial  at  (XI)  and  (GND),  and  then 
opening  the  grid  switch  (T),  we  can  oper- 
ate on  the  loop  aerial.  The  tap  switch 
(T)  cuts  out  the  secondary  coil  (L2) 
which  is  necessary  on  loop  reception. 
Coil  (L3)  suppresses  oscilations. 

When  operating  on  the  flat  top  aerial, 
or  a  type  similar  to  the  usual  outdoor 
aerial,  the  coupling  between  the  primary 
(LI)  and  the  secondary  (L2)  must  be  very 
"loose;"  that  is,  there  must  be  a  consider- 
able space  between  the  two  coils.  For  this 
reason,  it  is  best  to  adopt  a  ready-made 
coupler  in  which  the  coupling  gap  can  be 
easily  adjusted  until  the  proper  degree  is 
found  by  experiment.  We  have  only  one 
control,  and  to  obtain  the  proper  selec- 
tivity in  local  jams  we  must  have  the 
proper  "looseness"  between  the  coils.  The 
home-made  coil  generally  contains  from 
12  to  15  turns  of  No.  26  D.  S.  C.  wire  on 
the  primary  (LI),  and  from  55  to  60  turns 
on  the  secondary  coil  (L2),  using  the  same 
size  wire.  The  distance  between  the  two 
coils,  or  the  coupling,  may  be  from  $4  to 
%  inch  or  even  greater. 

By  using  a  4.5  volt  three  cell  "C"  bat- 
tery at  (C),  we  usually  get  greater  sensi- 
tivity and  signal  strength,  and  the  battery 
also  reduces  the  tendency  towards  free 
oscillations  in  the  circuit.  However,  the 
"C"  battery  can  be  omitted  in  many 
cases  without  serious  loss.  The  switch 
(T)  can  be  the  usual  form  of  tap  switch 
with  one  active  contact  point,  and  one 
dead  contact. 

The  first  radio  frequency  tube  (Tl), 
which  follows  the  tuning  inductance,  is 
provided  with  the  choke  coil  (CC)  con- 
nected to  the  plate  at  one  end  and  to  the 
(+B)  line  at  the  other,  so  that  from  90 
to  135  volts  of  "B"  battery  will  be  main- 


tained on  the  plate.  The  plate  of  tube 
(Tl)  is  coupled  to  the  grid  of  the  second 
R.  F.  tube  (T2)  through  the  fixed  coup- 
ling condenser  (Kl)  which  is  ordinarily 
of  0.002  mf.  capacity.  This  condenser 
prevents  the  application  of  the  plate 
voltage  to  the  grid  of  (T2)  and  thus  pre- 
vents the  high  "B"  voltage  from  paralyz- 
ing this  tube.  The  choke  coil  (CC)  can 
be  the  secondary  winding  of  an  audio 
transformer,  and  as  will  be  seen,  prevents 
the  R.  F.  plate  output  from  short  circuit- 


For  those  who  want  greater 
distance,  Mr.  Rathbun  has  de- 
signed the  six  tube  portable, 
but  with  resistance  coupled 
audio  amplification  shown  in- 
stead of  the  transformer  method 
of  coupling. 

The  change  lies  with  the 
builder.  A  great  deal  of  space 
may  be  saved  by  the  use  of 
resistance  coupling  and  at  the 
same  time  it  delivers  good 
quality. 


ing  through  the  "B"  battery.  It  allows 
the  "B"  battery  to  go  to  the  plate  of  the 
first  tube,  however,  but  stops  the  high 
frequency  current  from  backing  out. 
This  requires  no  control. 

Filament  Controls 

ALL  of  the  amplifying  tubes,  five  in 
number,  are  provided  with  auto- 
matic filament  controls  which  maintain 
the  amplifying  tube  current  at  the  proper 
intensity  without  rheostats  or  other 
manual  controls.  This  is  a  decided  step 
toward  simplicity  and  compactness,  and 
prolongs  the  life  of  the  tubes  by  holding  the 
filaments  constantly  at  the  proper  temper- 
ature. A  manual  rheostat  (R)  of  the 
usual  form  must  be  provided  for  the 
detector  tube  (T3)  as  this  has  a  rather 
critical  filament  adjustment  that  cannot 
be  automically  controlled.  The  rheostat 
(R)  is  represented  on  the  front  of  the  panel 
by  a  knob  as  shown  by  Fig.  3,  and  is  the 
only  control  outside  of  the  condenser  dial 
(CI).  A  switch  (SW)  must  be  provided  for 
shutting  off  the  filament  current  when  the 
set  is  not  in  use.  It  is  no  longer  possible  to 
turn  off  the  amplifying  tubes  indepen- 
dently as  when  the  usual  form  of  rheostat 
is  used.  This  can  be  an  ordinary  battery 
switch  of  the  type  to  be  found  at  any 
radio  store. 

A  second  choke  coil  (CC)  is  shown  con- 
nected to  the  plate  circuit  of  the  second 
radio  tube  (T2),  and  as  this  is  exactly 
similar  to  the  first,  there  will  be  no  further 
comment.  The  output  of  tube  (T2)  leads 
to  the  detector  tube  through  the  0.00025 
mf.  grid  condenser  (K2).  It  should  be 
noted  that  a  one  megohm  grid  leak  (V), 
shown  dotted  on  the  grid  of  tube  (T2), 
will  often  prove  of  advantage.  It  should  at 
least  be  tried  out  in  the  position  indicated 
by  the  dotted  lines  before  completing  the 
set,  for  it  sometimes  stabilizes  the  first 


tubes  and  increases  their  effectiveness. 
At  tube  (T3)  we  have  the  detector  tube 
which  is  connected  into  circuit  by  the 
0.00025  mf.  fixed  grid  condenser  (K2),  and 
the  one  megohm  grid  leak  (GL1).  As  with 
all  the  other  tubes,  this  is  a  "199"  tube, 
but  to  prevent  critical  rheostat  adjust- 
ments the  plate  is  supplied  with  45  volts 
by  an  intermediate  tap  at  the  "B"  bat- 
tery. From  the  detector  tube  on,  all  of  the 
stages  are  resistance  coupled  by  the 
50,000  ohm  resistances  (M1-M2-M3)  and 
the  grid  leaks  (GL2-GL3-GL4).  The 
hand  controlled  rheostat  is  shown  at  (R) 
by  which  the  detector  filament  can  be 
controlled  accurately  for  any  conditions. 
For  use  with  "199"  tubes,  the  resistance 
of  (R)  should  be  from  30  to  40  ohms,  the 
former  for  dry  cell  operation  and  the 
latter  for  use  with  storage  cells. 

Resistance  Coupled  Audio 

A  LL  of  the  three  audio  frequency  tubes 
-f*-  (T4-T5-T6)  are  supplied  with  the 
full  "B"  battery  voltage  through  the 
fixed  resistances  (M1-M2-M3)  which  have 
a  resistance  of  50,000  ohms.  The  plates 
and  grids  of  the  tubes  are  connected  by 
means  of  the  fixed  condensers  (K3-K4- 
K5)  of  0.005  mf.  capacity.  This  value 
is  not  critical,  and  0.006  mf.  fixed  con- 
densers can  also  be  used  if  this  is  the  only 
capacity  to  be  found  in  stock  at  your 
radio  store.  They  must  be  of  the  mica 
dielectric  type,  or  condensers  in  which  the 
plates  are  separated  by  thin  sheets  of 
mica  insulation. 

The  grid  leaks  (GL2,  GL3,  GL4) 
of  the  audio  tubes  "taper"  toward  the 
rear;  that  is,  the  last  tube  has  a  higher 
leak  resistance  than  that  of  the  first 
audio  amplifying  tube.  (GL2)=1.0 
megohm,  (GL3)  =5.00  megohm,  and 
(GL4)  =25.00  megohm.  This  arrange- 
ment gives  a  stronger  bias  to  the  grids 
on  the  tubes  which  are  most  heavily 
loaded,  and  therefore  results  in  a  better 
distribution  of  amplification  through  the 
three  stages.  The  output  of  the  sixth 
tube  (T6)  leads  to  the  output  jack  (Jl). 

A  full  90  volts  must  be  maintained  on 
the  plates  of  all  amplifier  tubes,  and  where 
possible,  this  should  be  increased  to  112.5 
volts  as  the  choke  and  resistance  coupling 
demands  a  higher  voltage  than  the  straight 
transformer  coupling  ordinarily  used. 
Two  vertical  type  45  volt  blocks  will 
take  up  the  minimum  amount  of  space 
in  the  cabinet  when  the  batteries  are 
carried  in  the  cabinet,  but  a  third  small 
22.5  volt  block  will  greatly  improve  the 
performance  by  raising  the  voltage  to 
112.5  volts.  The  great  trouble  with  a 
portable  set  is  to  get  the  batteries  into 
place  without  monopolizing  all  of  the 
cabinet  space.  When  the  set  is  built  for 
ordinary  stationary  service,  then  we  can 
use  three  45  volt  blocks  of  "B"  battery, 
giving  135  volts,  and  will  thus  obtain 
the  maximum  output  of  the  tubes.  The 
small  size  "B"  batteries  must  be  used 
for  the  portable  set. 

Filament  or  "A"  batteries  are  to  be 
No.  6  cells  and  are  connected  up  in  series 
to  give  a  total  of  4.5  volts  across  the 
rheostat.  When  possible,  these  should 
be  square  batteries  so  that  the  maximum 
amount  of  battery  material  can  be  put 
into  a  minimum  of  space.     The  demand 


72 


RADIO  AGE  for  August,  1925 


of  the  six  tubes  is  slightly  greater  than 
that  ordinarily  recommended  for  con- 
tinuous service  (0.36  ampere),  but 
with  careful  handling  they  can  be  made 
to  last  for  a  long  time  before  replacement 
becomes  necessary. 

Reason  for  Six  Tubes 

^^7TTH  transformer  coupling  on  both 
*  *  radio  frequency  and  audio  frequency 
stages,  a  five  tube  set  is  commonly  built 
with  two  radio  stages,  detector,  and  two 
audio  stages.  With  choke  coils  in  the 
radio  stages  and  resistance  coupling  in 
the  audio  stages,  the  amplifying  power 
of  the  tubes  is  somewhat  reduced  so 
that  one  more  tube  will  be  required  to 
give  the  same  results.  However,  this  is 
more  than  compensated  for  by  the  sim- 
plicity of  the  controls  and  the  clear 
toned,  noiseless  operation  of  the  set. 
It  has  a  far  better  tone  than  with  the 
usual  arrangements  and  can  be  handled 
by  the  rawest  novice  in  radio. 

Fig.  3,  showing  the  front  elevation  of 
the  panel  and  cabinet,  gives  a  good  idea 
of  the  general  arrangement  of  the 
receiver  when  designed  as  a  portable  set. 
The  cabinet  is  really  divided  into  two 
parts,  (1)  the  upper  portion  covered,  by 
the  panel  being  for  the  radio  circuit 
proper  while  (2)  the  lower  compartment 
houses  the  "A"  and  "B"  batteries.  As 
this  is  a  special  arrangement,  the  cabinet 
and  panel  will  have  to  be  made  specially 
for  the  job  and  it  is  not  likely  that  a  ready- 
made  cabinet  or  panel  can  be  found  which 
will  exactly  fit  the  conditions. 

In  the  front  view  of  Fig.  3  we  see  that 
the  panel  contains  all  of  the  controls, 
and  also  the  three  binding  posts  for  the 
aerial  (ANT-X1-GND).  The  dial  of  the 
tuning  condenser  is  at  (CI),  and  for 
accuracy  this  should  be  a  four-inch  dial 
with  some  sort  of  vernier  arrangement, 
as  the  tuning  -is  exceedingly  sharp. 
The  rheostat  control  (R)  for  the  detector 
tube  is  at  the  right  of  the  condenser  dial. 
The  battery  switch  for  turning  the  "A" 
battery  current  on  and  off  is  at  "SW" 
and  the  output  jack  is  (Jl).  In  the 
upper  right  hand  corner  of  the  panel  is 
the  grid  switch  (T)  by  which  the  set 
can  be  thrown  over  from  flat  top  aerial 
to  loop  operation.  This  is  all  there  is 
to  the  control  of  the  set  and  its  external 
connections. 

As  will  be  seen  from  the  side  sectional 
view,  Fig.  3A,  the  panel  is  set  back  from 
the  front  edge  of  the  cabinet  so  that  the 
front  door  will  clear  the  knobs  and   dials. 

The  door  swings  on  two  hinges  (h)  and 
is  just  large  enough  to  cover  the  panel, 
the  top  of  the  battery  compartment 
being  at  the  lower  edge  of  the  door. 
Any  suitable  catch  or  lock  (I)  can  be 
used  on  the  left  hand  edge  of  the 
cabinet  for  fastening  the  door,  and  a 
lock  is  not  a  bad  idea  even  in  the  home, 
as  it  prevents  children  from  tampering 
with  the  set.  At  the  top  is  a  leather 
handle  (G)  fastened  to  the  cabinet  by 
standard  hardware  that  can  easily  be 
obtained  from  a  trunk  or  suitcase  house 
or  from  some  hardware  stores.  The  lower 
battery  compartment  door,  just  below  the 
panel,  is  shown  closed.  It  is  through  this 
opening  that  we  replace  the  batteries. 
Blueprints  of 


'THE  finish  of  the  cabinet  depends 
*-  upon  the  taste  and  ingenuity  of  the 
builder.  It  can  be  polished  with  wax  or 
varnished  in  natural  wood  finish,  or 
it  can  be  covered  with  leatherette  or 
similar  black  grained  covering  material. 
If  leatherette  is  used,  then  all  of  the 
corners  must  be  well  rounded  off  so  that 
the  material  will  not  get  loose  or  buckle 
along  the  edges.  The  front  face  of  the 
battery  compartment  door  comes  flush 
with  the  face  of  the  cabinet  and 
panel  door;  hence  this  part  is  given  the 
same  finish  as  the  outside  of  the  cabinet. 
Rubber  pads  or  feet   (i)   prevent  the  set 


BILL  OF  MATERIALS  USED 

The  following  list  will  give  the  materials  used  and  their 
sizes.  The  parts  are  listed  according  to  the  same  refer- 
ence letters  used   on  the  drawings  so  that  their  relation 

PORTABLE  RECEIVER  MATERIALS 

"A" — 3  Filament  "A"  Dry  Batteries.  1.5  volt.  No.  6. 

ANT — 1  Loop  aerial  (optional) ,  2  Ft.  Square. 

"B" — 2  "B"  Plate  Batteries,  Vertical  type,  45  Volt 

"C" — 1  "C"  Bias  Battery,  Three  cell,  small,  4.5  volts 

CI— 1  Vernier  Variable  Condenser  (23  plate).  0.0005  mf 

CC — 2  100  Millihenry  Choke  coils,  or  audio  trans- 
former secondary  coils, 

D — 1  Special  cabinet,  as  specified  in   drawings 

E — 1  Special  Panel,  as  specified  in  drawings,  3/16-inch 
Bakelite. 

F-H — 2  Special  Shelves,  as  specified  in  drawings,  3-16 
inch  Bakelite  5"x6^4". 

G — 1  Carrying  Handle  Complete,  Standard. 

GL1— 1  Grid  Leak.  1.00  Megohm. 

GL2— 1  Grid  Leak,  1.00  Meghom. 

GL3— lGrid  Lejk,  5.00  Megohm. 

GL4 — 1  Grid  Leak,  25.00  Megohm. 

h — 4  Hinges  or  butts.  Standard. 

I — 2  Lock  Catch.  Standard. 

i — i  Rubber  pads  or  feet,  Medium  Size. 

Jl — 1  Single  Circuit  Jack,  Standard. 

Kl — 1  Fixed  Condenser,  Mica  dielectric,  0.002  mf. 

K2 — 1  Fixed  Condenser,  Mica  dielectric.  Grid  ctiPB, 
(U>OOL>5  mf. 

K3 — 1  Fixed  Condenser,  Mica  dielecric.  0.005  or 
0.006  mf. 

K4 — 1  Fixed  Condenser,  Mica  dielectric,  0.005  or 
0.006  mf. 

K5 — 1  Fixed  Condenser,  Mica  dielectric,  0.005  or 
0.006  mf. 

L — 4  Brass  Angle  Brackets,  Standard. 

L1-L2 — 1  Aperiodic  Type  Coupler,  Standard. 

M1-M2-M3 — 3  50.000     ohm     Resistor     Units, 

R — 1  Filament  Rheostat,  30-40  ohms. 

rl-r2,  etc. — 5  Automatic  Fila.  Controls  (Amperites) 
199-4.5  volts. 

SW — 1  Battery  Switch,  Standard. 

T — 1  Tap  Switch,  Standard. 

t — 2  Contact  points,  with  two  stops.  Standard. 

T1-T2,  etc.— 6  Tubes,  "199." 

U — 6  Absorber  Base  Tube  Sockets,  "199"  Type. 

40"  Tinned  Square  Copper  Bus  Wire,  No.  14. 

75  Solder  Clips,  Tinned.  Standard. 

3  Binding  Posts,  Composition  Caps,  Standard. 

Z — 4  Brass  angle  connections,  Standard. 

V — 1  Leak.  1  megohm. 

VM — Filament  voltmeter,  0.8  volts. 


from  scratching  finished  surfaces  on  which 
it  may  be  placed,  and  further,  they 
prevent  or  help  to  prevent,  the  ringing 
microphonic  noises  experienced  with 
"199"  tubes. 

Shelf  for  Tubes 

The  side  sectional  view  of  Fig.  3A  shows 
that  a  shelf  (F)  is  used  for  carrying  the 
first  three  tubes,  and  that  this  shelf  is 
attached  to  the  panel  (E)  by  means  of 
brass  angle  brackets  (L).  The  shelf  (F) 
carries  the  first  two  tubes  (T1-T2)  of 
the  radio  frequency  circuit  and  also  the 
detector  tube  (T3).  Below  the  upper 
shelf  is  the  lower  shelf  (H)  which  carries 
the  three  audio  tubes  (T4-T5-T6).  As 
the  resistance  units  and  other  parts  of 
the  circuit  are  carried  on  the  underside 
of  the  shelves  with  the  sockets  on  top, 
we  must  be  sure  to  leave  room  to  accom- 
modate the  height  of  the  tubes  over 
their  sockets,  plus  the  thickness  or  height 
of  the  resistance  units  and  the  condensers, 
plus  clearance. 

The  material  used  for  the  cabinet  can 
be  5-16  inch  or  3-8  inch  thick,  but  if  care- 
fully constructed  with  dovetailed  or 
matched  corners,    will   be   perfectly  safe 


The  Magazine  of  the  Hour 

when  built  of  5-16  inch  stock.  The 
bakelite  panels  should  not  be  less  than 
3-16  inch  and  this  also  covers  the  shelves 
which  should  be  of  the  same  material 
as  the  panels;  that  is,  hard  rubber,  bake- 
lite or  formica.  The  shelves  carry  the 
wiring  and  many  of  the  current  carrying 
parts  so  that  their  insulating  value  should 
be  fully  equal  to  that  of  the  panels. 

We  cannot  go  further  into  the  details 
of  the  cabinet  construction,  but  the  con- 
struction will  be  clearly  seen  by  those 
who  are  competent  to  undertake  work 
of  this  sort,  and  if  one  is  not  sure  of  being 
able  to  build  this  cabinet,  the  drawings 
are  amply  dimensioned  for  a  practical 
cabinet  maker.  If  you  give  the  job  to 
a  cabinet  maker,  I  suggest  that  you  also 
give  him  the  panels  and  shelves  so  that 
he  can  get  a  good  fit  betwen  the  edges 
of  the  panel  and  the  rabbet  of  the  cabinet. 

Arrangement  of  Apparatus 

TT^IG.  4  shows  the  arrangement  of  the 
-*-  apparatus  as  seen  from  the  rear  of  the 
panel.  The  six  tube  sockets  (U)  are 
placed  in  groups  of  three  on  the  two 
shelves  (F)  and  (H),  and  the  outlines  of 
the  tubes  are  indicated  by  thin  dot  and 
dash  lines  so  that  the  allowance  for  shelf 
clearance  can  be  easily  seen.  The  tubes 
are  numbered  so  that  their  relation  to 
the  circuit  drawings  of  Figs.  1  and  2  can 
be  easily  followed,  and  the  sockets  can 
be  located  in  the  same  way.  Fig.  3A 
and  Fig.  4  can  be  used  in  combination, 
thus  obtaining  the  side  and  rear  eleva- 
tions of  the  assembly. 

It  will  be  seen  that  the  shelves  are  cut 
off  at  the  right  in  Fig.  4  to  accommodate 
the  variable  tuning  condenser  (CI)  and 
the  tuning  inductance  (LI— L2).  On 
the  lower  sides  of  the  shelves  will  be  seen 
the  coupling  resistances,  grid  condenser, 
gridleaks  and  the  wiring.  In  making 
allowance  for  the  space  between  shelves, 
measure  the  height  of  the  tube  plus  the 
height  of  the  socket,  plus  a  little  more 
clearance  so  that  the  tubes  can  be  taken 
out  of  the  sockets  and  replaced  without 
tearing  the  set  to  pieces.  In  other  words, 
the  true  height  of  the  socket  assembly 
is  the  sum  of  the  tube  height,  plus  the 
socket  height,  plus  J^  inch  clearance 
between  the  lower  end  of  the  tube  and 
the  top  of  the  socket. 

The  arrangement  of  the  battery  com- 
partment in  general  with  the  batteries 
in  place  is  marked.  Strong  flat  springs 
made  from  flat  spring  brass  plates  bear 
on  one  side  of  the  batteries  and  hold  them 
in  place  against  jolts  and  jars  when  the 
set  is  being  carried.  Connections  between 
the  apparatus  and  batteries  are  made  by 
means  of  flexible  fixture  wire  which  can 
be  obtained  from  any  electrical  store. 
This  is  very  flexible  and  well  insulated, 
and  makes  an  ideal  connection,  i  The  ends 
of  the  fixture  wire  should  be  provided 
with  "spade"  type  tips  soldered  to  the 
copper  strands,  and  these  make  a  perman- 
ent contact  with  the  connection  screws 
which  is  easily  attached  and  which  does 
not  loosen  under  ordinary  conditions. 
Do  not  attempt  placing  the  strands  of 
wire  directly  under  the  binding  screws, 
for  when  connected  up  in  this  way  they 
are  almost  certain  to  get  undone. 


the  Six-Tube  "Portatron"  on  Pages  Following 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


73 


Economy  of  Arrangement  Is  Vital 


\  S  WILL  be  seen,  the  part  of  the 
•^*-  assembly  taken  up  by  the  receiver 
proper  is  very  small,  the  panel  measuring 
10%  long  and  11  yi  deep,  but  for  some 
purposes  the  total  height  with  the 
batteries  included  may  be  too  great  to 
be  practicable.  In  such  a  case,  the 
battery  compartment  can  be  made 
separate,  terminating  the  receiver  por- 
tion at  the  board  shown  running  over 
the  tops  of  the  batteries.  This,  however, 
makes  it  necessary  to  reconnect  the  bat- 
terieseverytimethat  the  receiver  is  set  up 
and  as  a  result  it  is  a  decided  nuisance. 

As  laid  out  in  the  drawings,  there  is 
ample  room  for  a  fifth  "B"  battery  if 
it  is  desired  to  operate  with  a  plate 
voltage  of  112j-£  volts,  or  a  sixth  "B" 
battery  if  we  wish  to  operate  at  135 
volts.  Further,  there  is  room  for  one 
spare  "A"  battery  if  it  is  desired  to  carry 
this   replacement    along   on   a   trip. 

The  voltmeter  (VM)  is.  a  very  desir- 
able instrument,  particularly  when  dry 
cell  "A"  batteries  are  used,  for  it  at 
once  indicates  the  drop  in  voltage  due 
to  weakening  batteries.  Unless  we  have 
some  means  of  testing  the  voltage 
occasionally,  we  are  likely  to  believe 
that  the  set  is  out  of  order  when  the 
voltage  drops,  and  waste  much  time 
chasing  for  trouble  in  the  wiring  when 
the  difficulty  actually  exists  in  the 
cells.  Just  because  automatic  filament 
controls  are  installed  for  the  regulation 
of  the  filament  current  is  no  reason 
why   the   voltmeter   should   be   omitted. 

Voltmeters  must  be  connected  properly 
according  to  polarity,  and  you  must 
be  guided  by  the  markings  on  the  instru- 
ment. If  the  polarity  is  wrong,  then 
the  needle  indicator  will  be  thrown 
against  the  wrong  end  of  the  scale. 
The  size  of  the  voltmeter  should  be  so 
chosen  that  the  full  voltage  will  bring 
the   needle  near  or  slightly  beyond  the 


center  of  the  graduated  scale  where 
the  divisions  are  the  largest,  and  the 
battery  voltage  should  not  throw  the 
needle   to   the   far   end   of   the   scale. 

Suppressing  Oscillations 

Free  oscillations  in  the  radio  fre- 
quency stages  are  the  greatest  difficulty 
in  the  construction  of  a  radio  frequency 
or  reflex  type  of  receiver,  and  we  must 
devise  some  system  for  stopping  these 
oscillations  if  we  expect  to  get  the  full 
output  of  the  set.  In  fact,  most  of  the 
trouble  reported  with  sets  having  radio 
frequency  stages  can  be  traced  to  im- 
proper or  imperfect  methods  of  damping 
down  the  oscillations.  There  are  a 
number  of  methods  of  stopping  oscilla- 
tions, among  which  are  the  potentio- 
meter, neutralizing  condensers,  bias  bat- 
teries, etc.,  but  in  thisreceiver  we  have  sim- 
plified the  problem  by  the  use  of  a  plate  re- 
actacne  coil  marked  (L3)  on  the  diagrams. 

Coil  (L3)  consists  of  four  or  five  turns 
of  wire  wound  on  the  end  of  the  tuning 
coil.  One  end  of  this  coil  is  connected 
to  the  plate  of  the  first  radio  tube  as 
shown,  while  the  other  end  is  left  opened 
or  is  unconnected.  As  one  end  is  opened, 
only  capacitative  current  will  flow  from 
the  plate  into  the  coil,  and  the  magnetic 
coupling  is  therefore  very  feeble,  as  it 
should  be.  Some  little  experimenting 
will  be  required  in  adjusting  this  coil 
before  it  just  stops  the  oscillations. 
It  may  be  that  the  plate  connection 
must  be  connected  to  the  other  end  of 
(L3),  or  that  the  whole  coil  must  be 
wrapped  on  the  other  end  of  the  tube. 
Varying  the  number  of  turns,  or  the 
distance  of  (L3)  from  (L2)  may  be 
required.  Just  because  you  have  not 
hit  the  proper  combination  on  the  first 
trial  is  no  proof  that  it  will  not  work. 
The  losses  are  at  a  minimum  with  this 


arrangement,  and  there  are  no  separate 
controls  as  when  a  potentiometer  is  used. 

In  addition  to  the  compensating  coil 
(L3),  the  "C"  battery  will  be  an  aid  in 
keeping  down  oscillations  and  increasing 
the    sensitivity   of    the    first    two    tubes. 

In  the  center,  and  at  the  bottom  of 
Fig.  1,  will  be  found  a  detail  of  a  small 
radio  frequency  choke  coil  which  can 
be  used  when  an  audio  frequency  trans- 
former secondary  is  not  available.  This 
consists  of  about  450  turns  of  No.  36 
D.  S.  C.  wire  wound  on  a  cardboard 
or  bakelite  tube  as  shown,  and  is  mounted 
on  the  upper  shelf  (F)  of  the  set.  Some 
little  experimenting  may  be  required 
to  get  the  most  effective  number  of 
turns,  but  the  coil  is  not  very  critical 
to  the  turns,  and  for  most  apparatus  the 
number  of  turns  shown  will  come  very 
close  to  the  best  effect.  We  must  have 
enough  turns  so  that  the  tubes  will  not 
paralyze  on  the  higher  wavelengths 
through  leakage  of  the  R.  F.  current 
to  the  ~"B"  battery. 

In  the  lower  right  hand  corner  of 
Fig.  1  is  a  detail  of  the  resistor  assembly 
used  in  the  audio  frequency  stages. 
We  can  assemble  the  resistors  and  grid 
leaks  on  the  shelves  by  means  of  clips 
as  shown,  or  better  yet,  we  can  buy 
these  completely  assembled  units  from 
ovir  advertisers,   at   a   reasonable   figure. 

Summary 

TN  tuning  this  set,  the  adjustment  of 
-*-  the  detector  rheostat  (R)  is  of  great 
importance,  for  there  is  one  position 
of  the  rheostat  where  the  detector  tube 
is  the  most  sensitive  and  gives  the 
greatest  volume.  This  generally  occurs 
when  the  rheostat  is  about  one-half  on, 
and  it  is  seldom  necessary  to  turn  on 
this  tube  to  full  brilliance  as  with  the 
amplifier     tubes. 


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S-_LT)0/\  S"*' 


78 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


Here   You  Are  I     A  Real  Receiver 

A  New  8-Tube  Super-Heterodyne 

By  JOHN  B.  RATHBUN 


SO  much  has  been  printed  in  RADIO 
AGE  upon  the  elementary  prin- 
ciples of  the  super-heterodyne  that  it 
seems  hardly  necessary  to  enter  again 
into  the  theory  in  much  detail. 

Briefly,  the  super-heterodyne  is  a 
special  form  of  radio  frequency  circuit 
in  which  radio  frequency  amplification 
takes  place  at  a  much  longer  wavelength 
than  that  of  the  incoming  radio  waves, 
thus  reducing  the  losses  in  the  tubes  and 
R.  F.  transformers  and  adding  to  the 
efficiency  of  the  set.  Broadcasting  wave- 
lengths ranging  from  200  to  600  meters 
are  converted  into  wavelengths  approxi- 
mating 10,000  meters  before  the  waves 
enter  the  radio  frequency  stages.  After 
amplification,  the  waves  then  are  rectified 
by  the  usual  detector  tube  producing 
audible  signals  which  can  be  further 
amplified  by  one  or  more  audio  stages. 

A  typical  eight  tube  super-heterodyne 
of  the  type  to  be  described  consists  of 
the  following  principal  unit  divisions  of 
tubes: 

(1)  The   first    detector   tube. 

(2)  Three  radio  frequency  amplifying 
tubes. 

(3)  One  oscillator  tube  used  as  a  fre- 
quency changer  of  the  heterodyne  type. 

(4)  One  second  detector  for  rectifying 
the  output  of  the  radio  frequency  stages 
and  thus  producing  audible  signals. 

(5)  Two  audio  frequency  stages  for 
increasing  the  volume  of  the  audio  com- 
ponent so  that  a  loud  speaker  can  be 
used. 

The  Detector  Tube 
TN  a  certain  respect,  the  first  detector 
-*-  tube  (1)  can  be  considered  as  a  radio 
frequency  amplifying  stage,  and  in  some 
circuits  is  used  exclusively  for  this  pur- 
pose without  the  conventional  grid  con- 
denser and  leak,  but  when  iron  core 
radio  frequency  transformers  are  used 
the  detector  tube  is  of  advantage  in 
providing   an    audio    component    in    the 

Blueprints  for 


less    of    the    incoming    radio    frequency. 

AC,  .  u  „  ■*.    TL.^.4-    /^.'r,,  ^  r.     The    oscillator    condenser    forms   one    of 
ouper  1  hat  Uives  the 


Distance  and  Tone 


first  stages  of  the  circuit.  It  should  be 
noted  that  the  R.  F.  tubes  and  trans- 
formers work  normally  at  a  frequency 
which  is  not  very  much  greater  than  the 
higher  audio  or  voice  frequencies,  and 
therefore  a  certain  amount  of  audio 
amplification  is  also  possible  in  the  radio 
stages,  when  iron  core  transformers  are 
used  at  this  point.  With  air  core  trans- 
formers the  audio  component  receives 
little  if  any  amplification  in  the  radio 
stages,  and  hence  under  these  conditions 
the  rectification  of  the  first  tube  (1)  is 
not  of  importance  and  can  be  considered 
and  used  as  a  strictly  radio  frequency 
stage.  The  advantages  and  disad- 
vantages of  either  system  are  still  a  matter 
of    some    dispute. 

We  now  come  to  the  oscillator  tube  (3) 
by  which  the  wavelength  or  frequency 
of  the  incoming  waves  is  converted  into 
the  desired  value  for  use  in  the  radio 
frequency  stages.  Really  this  tube  is  an 
independent  unit  as  far  as  the  rest  of  the 
circuit  is  concerned,  for  it  does  not  enter 
directly  into  the  amplification  or  rectifi- 
cation of  the  waves.  It  simply  produces 
a  series  of  independent,  continuous 
oscillations,  which  are  combined  with  the 
incoming  radio  waves  to  form  a  third 
series  of  oscillations  having  a  greater 
wavelength  or  lower  frequency  than 
either  of  the  original  series.  This  method 
of  changing  frequencies  is  known  as 
heterodyning.  The  third  wave  is  ampli- 
fied by  the  succeeding  radio  stages. 
The  frequency  of  the  oscillations  set  up 
by  the  oscillator  tube  is  determined  by  an 
inductance  coil  and  a  variable  condenser 
in  such  a  way  that  a  constant  frequency 
is  maintained  in  the  R.  F.  stages,  regard- 


le  two  tuning  controls  of  the  circuit. 
The  R.  F.  Transformers 


ALL    of 
■**-  former 


the  radio  frequency  trans- 
rmers  operate  at  a  constant  fixed 
wavelength  or  frequency  at  which  maxi- 
mum amplification  takes  place,  regard- 
less of  the  frequency  of  the  broadcasting 
station  which  may  then  be  tuned  in.  This 
optimum  frequency  is  determined  by  the 
windings  of  the  transformers  and  more 
particularly  by  the  filter  condensers 
placed  across  the  first  or  last  R.  F. 
transformers.  The  transformers  are 
therefore  sharply  tuned  to  a  single  definite 
wavelength  or  frequency  to  which  the 
heterodyned  waves  must  be  adjusted 
by  means  of  the  oscillator  variable,  con- 
denser. As  the  transformers  will  not 
respond  to  any  other  frequency  than  that 
determined  by  the  filter,  the  oscillator 
condenser  becomes  an  effective  tuning 
control,  which  in  connection  with  the 
aerial  or  loop  condenser  insures  a  high 
degree    of    selectivity. 

All  the  radio  frequency  transformers, 
whether  of  the  air  core  or  iron  core  type, 
are  of  the  "long  wave"  design  especially 
designed  for  the  super-heterodyne  cir- 
cuit. In  the  circuit  illustrated,  the 
transformers  are  designed  for  operation 
on  approximately  45  kilocycles  (45,000 
cycles  frequency)  which  corresponds  to  a 
wavelength  of  6,000  meters.  This  is 
not  a  fixed  standard  frequency  which 
must  be  maintained  strictly  in  all  cases, 
but  has  been  found  in  practice  as  the  most 
effective  compromise  for  the  circuit  at 
hand.  Actually,  the  waveband  may 
extend  from  1,200  to  25,000  meters  in 
many  circuits,  but  at  either  extreme  cer- 
tain objectionable  features  appear  which 
make  the  6,000  meter  type  the  logical 
compromise  for  iron  core  transformers. 
(Turn  the  page) 


the  New  Super-Heterodyne  on  Pages  Following 


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RADIO  AGE  for  Aueust,  1925 


The  Magazine  of  the  Hour 


79 


Uniformity  of  Tubes  Vital  in  "Super 


Circuit  Diagrams 

Fig.  1  is  the  schematic  circuit  drawing 
of  the  super-heterodyne  developed  by 
Mr.  Posth  of  the  Radio  Doctors,  Inc., 
Chicago,  and  which  has  been  built  by  a 
number  of  amateurs  with  excellent 
results.  It  is  not  a  radical  departure  from 
conventional  practice,  but  is  a  simple, 
compact  layout  which  is  easily  con- 
structed by  the  novice  in  "dyne"  cir- 
cuits with  an  excellent  chance  of  getting 
results  immediately  after  the  completion 
of  the  set.  It  is  the  result  of  nearly  a 
year's  continual  experimenting  by  one 
who  has  alternately  added  and  then 
eliminated  various  experimental  features 
which  have  been  brought  up  from  time 
to  time  in  heterodyne  development 
until  the  present  circuit  was  arrived  at. 

Fig.  2  is  a  picture  diagram  of  the  hook- 
up which  will  be  of  service  to  those  who 
have  not  yet  delved  into  the  mysteries  of 
conventional  diagrams.  Here  each  part 
is  drawn  out  as  it  actually  appears  in  the 
proper  proportion,  with  the  wiring  runs 
located  at  the  most  advantageous  points. 
The  letters  and  figures  on  Fig.  1  cor- 
respond to  those  marked  on  Fig.  2,  so 
that  the  relation  between  the  two  draw- 
ings can  be  easily  traced  out.  For  con- 
venience, Fig.  2  is  divided  into  two  parts. 
The  lower  half  of  the  drawing  represents 
a  plan  view  of  the  baseboard  and  appa- 
ratus as  it  appears  to  the  observer  on 
looking  straight  down  on  the  set.  The 
upper  half  is  the  rear  view  of  the  panel 
as  seen  from  the  rear  of  the  assembly. 
Between  the  upper  and  lower  views  we 
see  the  connecting  wiring  drawn  in  heavy 
lines,  which  connect  the  apparatus 
mounted  on  the  baseboard  to  that 
attached  to  the  rear  of  the  panel.  Ar- 
ranged in  this  way,  the  connections  are 
easily  followed. 

Fig.  3  is  a  front  elevation  of  the  panel 
which  shows  the  controls  and  the  center 
to  center  dimensions  between  the  various 
units  mounted  on  the  panel.  As  will  be 
seen  from  the  blueprints,  the  panel  is 
8°x32  "xl/4",  a  reasonable  size  for  a 
super-heterodyne  and  a  panel  not  much 
longer  than  that  used  with  many  tuned 
radio  frequency  outfits.  The  circuit  is 
arranged  exclusively  for  use  with  a  loop 
aerial,  and  with  this  arrangement  the 
loop  plays  no  small  part  in  gaining 
absolute  selectivity  in  districts  where 
there  are  a  number  of  broadcasting 
stations  located  within  a  short  distance 
of  the  receiver. 

Starting  in  with  either  Fig.  1  or  Fig.  2, 
depending  upon  the  experience  of  the 
reader,  we  note  the  two  variable  con- 
densers (CI)  and  (C2)  mounted  on  the 
panel  at  the  right.  Both  are  of  the  low 
loss  type  with  external  vernier  adjust- 
ments, and  both  have  a  maximum  capaci- 
ty of  O.OOOS  microfarad  or  the  capacity  of 
the  standard  23  plate.  Condenser  (CI) 
controls  the  oscillation  frequency  of  the 
oscillator  tube  (1)  and  the  oscillator  coil 
(OS).  Condenser  (C2)  tunes  the  loop 
and  the  grid  circuit  of  the  first  detector 
tube    (2).      These    are    the    only    tuning 


controls  used  and  therefore  the  actual 
operation  of  tuning  is  much  simpler  than 
with  the  usual  tuned  radio  frequency  set. 
Further  along  the  panel  we  have  four 
filament  control  rheostats  (R1-R2-R3) 
with  resistances  varying  according  to  the 
number  of  tubes  that  they  control. 
Rheostats  are  based  on  the  use  of  201A 
tubes  throughout  both  for  the  amplifiers 
and  detectors.  The  three  rheostats 
marked  (Rl)  have  a  resistance  of  20  ohms 
and  control  respectively  the  oscillator 
tube  (1),  the  first  detector  tube  (2)  and 
the  second  detector  tube  (6).  Rheostat 
(R2)  controls  the  three  radio  frequency 
tubes  (3-4-5),  and  because  of  the  greater 
current  has  a  resistance  of  only  six  ohms. 
Rheostat  (R3)  has  a  resistance  of  15  ohms 
for  the  control  of  the  two  audio  tubes 
(7-8). 

Watching  Potentiometer 
A  T  (PO)  is  a  400  ohm  potentiometer  or 
-^*-  stabilizer  which  controls  the  grid 
potential  of  the  radio  frequency  stages. 
In  actual  operation  the  potentiometer 
has  a  marked  influence  on  the  volume  and 
selectivity  but  is  not  frequently  used 
after  the  set  is  set  into  operation  in  the 
same  sense  that  the  condensers  are  used. 
A  potentiometer  of  lower  resistance  is 
not  recommended,  as  it  does  not  give 
sufficiently  accurate  control  of  the  grid 
potential.  A  voltmeter  (VM)  is  desirable 
for  indicating  the  potential  across  the 
filaments  of  the  radio  tubes,  but  it  is  not 
absolutely  essential.  By  means  of  this 
voltmeter  (0-10  volt  scale),  the  tubes  can 
be  kept  accurately  to  the  point  of  great- 
est sensitivity.  An  ammeter,  shown 
by  (AM)  gives  the  total  current  consumed 
by  all  tubes  in  the  circuit.  A  battery 
switch  as  at  (SW)  is  very  convenient 
and  is  an  insurance  against  the  accidental 
burning  of  the  tubes  after  leaving  the 
set  for  the  night.  It  makes  the  complete 
readjustment  of  the  rheostats  unneces- 
sary when  the  set  is  used  the  second 
time.  All  of  the  above  apparatus  is 
mounted  on  the  panel  as  shown  by  the 
.  upper  view  of  Fig.  2. 

Three  output  jacks  are  provided. 
Inserting  the  plug  into  jack  (JD)  gives 
reception  from  the  tubes  up  to  and  in- 
cluding the  first  detector  tube  (6)  and 
this  corresponds  to  the  detector  tube 
circuit  of  the  ordinary  regenerative 
circuit.  Plugging  into  jack  (JI)  gives 
the  addition  of  one  stage  of  audio  ampli- 
fication, while  jack  (J2)  includes  all  of 
the  tubes  or  two  stages  of  audio.  Ex- 
perience has  shown  that  one  stage  of 
audio  is  all  that  is  required  for  loud 
speaker  operation  on  all  but  the  faintest 
and  most  distant  stations. 

An  oscillator  coil  (OS)  of  the  fixed 
winding  type  is  located  between  the  first 
detector  tube  (2)  and  the  oscillator  tube 
(1).  The  functions  of  this  inductance 
coil  have  been  described  before.  This 
coil  is  very  compact  and  requires  no 
adjustment.  The  inside  bakelite  tube 
is  1.5  inch  in  diameter  and  carries  about 
four  turns  of  wire  near  its  center  which 
corresponds  to  the  "pick-up  coil"  of  the 
usual    heterodyne    oscillator    coil.      The 


outer  tube  is  2.5  inches  in  diameter  and 
carries  both  the  grid  and  plate  coils  of 
the  oscillator  circuit.  The  grid  coil 
carries  20  turns  of  No.  26  D.  S.  C.  wire 
and  the  plate  coil  consists  of  40  turns  of 
the  same  size  wire.  The  latter  is  spaced 
about  one  half  inch  from  the  grid  coil. 
A  detail  of  the  oscillator  coil  is  shown  in 
Fig.  4  where  the  external  plate  and  grid 
coils  are  clearly  seen.  Theinnerand  outer 
tubes  are  mechanically  connected  by  short 
pieces  of  small  fiber  tubing  through  which 
brass  screws  are  run.  When  tuned  by  the 
0.0005  mf  condenser  (CI),  this  oscillator 
will  fully  cover  the  ordinary  range  of 
broadcasting  wavelengths. 

At  (2)  we  have  the  first  detector  tube 
with  the  grid  condenser  (K2)  of  0.00025 
mf  capacity  and  the  grid  leak  (GL)  with 
a  resistance  of  two  megohms.  As  will  be 
seen  from  the  plan  view  in  Fig.  2,  the 
oscillator  coil  and  the  two  tubes  (1)  and 
(2)  are  located  well  back  on  the  base- 
board, so  as  to  clear  the  variable  con- 
densers (C1-C2)  indicated  by  the  dotted 
lines.  The  outline  of  the  baseboard  is 
indicated  by  (F).  A  bypass  condenser 
(Kl)  has  a  capacity  of  0.005  mf. 

Next  in  order  come  the  radio  frequency 
stages  consisting  of  the  tubes  (3),  (4), 
(5)  and  the  long  wave  radio  transformers 
(RD1-RD2-RD3-RD4).  All  of  the  trans- 
formers are  of  the  iron  core  45  kilocycle 
type  and  are  tuned  to  work  in  agreement 
with  the  oscillator  by  means  of  the  fixed 
condensers  (K1-K4).  (RD1)  is  the  input 
and  (RD4)  is  the  output  transformer. 
Any  iron  core  of  45  kilocycle  type  can  be 
employed.  Condenser  (K4)  has  a  ca- 
pacity of  0.00025  mf.  Owing  to  the  body 
capacity  which  is  sometimes  in  evidence, 
it  is  frequently  desirable  to  ground  the 
metal  cases  of  the  transformers  as  indi- 
cated by  the  dotted  line  (g). 

With  the  particular  transformers  shown 
in  Fig.  2,  the  tube  sockets  and  trans- 
formers can  be  set  very  close  together, 
about  2  7/8  inch  centers.  The  trans- 
formers are  of  the  metal  shielded  upright 
cylindrical  type,  which  lend  themselves 
nicely  to  compact  formation.  The  grid 
post  (G)  of  the  output  transformer 
(RD4)  goes  to  the  grid  condenser  (K5) 
and  grid  leak  (GL)  of  the  second  detector 
tube  (6).  The  grid  condenser  (K5)  has  a 
capacity  of  0.0005  mf,  while  the  grid 
leak  has  a  resistance  of  2  megohms. 

201A  Tubes  Used 

BY  using  201A  tubes  throughout  with 
a  current  consumption  of  0.25 
ampere  per  tube,  the  total  current  is  only 
8x0.25  =  2  amperes,  the  exact  amount 
of  current  taken  by  a  five  tube  neutrodyne 
when  a  soft  detector  tube  is  used.  As  a 
soft  detector  of  the  "200"  type  take^ 
about  one  ampere  and  introduces  a  cer- 
tain amount  of  hissing  tube  noise,  its 
use  is  not  recommended  in  this  set. 
Owing  to  the  high  potentials  on  the  grids 
of  the  tubes,  it  is  necessary  to  use  the 
highest  grade  of  sockets  to  insure  against 
leakage  and  internal  capacity  effects. 
For  the  same  reason,  the  bottoms  of  the 
sockets  should  be  raised  well  above  the 


80 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


face  of  the  baseboard  by  means  of  spacers 
or  liners,  say  about  1/4  to  3/8  inch  above 
the  board. 

For  the  best  results  all  tubes  should  be 
carefully  matched  by  the  dealer  before 
delivery,  for  all  of  the  tubes  in  the  radio 
frequency  stages  at  least  must  have 
exactly  the  same  electrical  characteristics. 
When  so  many  radio  frequency  tubes  are 
connected  up  in  cascade  (series),  and  when 
the  transformers  are  exactly  matched  as 
they  should  be,  any  small  difference  in 
the  tube  characteristics  will  cut  down  the 
output  to  an  alarming  extent.  Matched 
tubes  may  cost  slightly  more  than  tubes 
taken  out  of  stock  at  random,  but  they 
are  well  worth  the  money.  Any  one  who 
has  constructed  a  neutrodyne  set  knows 
how  greatly  tubes  of  the  same  make  and 
type  vary  among  each  other,  and  how 
difficult  it  is  to  get  dissimilar  tubes  to 
act  together. 

Large  bypass  fixed  condensers  must  be 
used  to  shunt  the  radio  frequency  cur- 
rents around  the  windings  of  the  poten- 
tiometer and  across  the  resistance  of  the 
"B"  batteries.  This  is  even  of  more 
importance  with  long  wavelengths  than 
at  broadcasting  frequencies  and  the  ca- 
pacities of  the  condensers  must  be  cor- 
respondingly greater.  Condenser  (K3) 
has  a  capacity  of  0.5  microfarad  and  is 
used  to  shunt  the  R.F.  current  around 
the  potentiometer  windings.  Fixed  con- 
denser (K6)  has  a  capacity  of  1.0  micro- 
farad and  shunts  the  "B"  battery. 
Smaller  condensers  should  not  be  used. 

Last  are  the  two  audio  frequency 
stages  at  the  extreme  left  of  the  board. 
Tubes  (7)  and  (8)  are  the  first  and 
second  audio  tubes  respectively,  while 
the  audio  frequency  transformers  will 
be  seen  at  (AT).  In  general,  these 
two  audio  stages  are  the  same  as  any 
audio  stages  but  owing  to  the  nature  of 
the  super-heterodyne,  it  is  necessary  to 
filter  the  output  by  means  of  certain 
fixed  condensers  so  that  the  second  stage 
can  be  worked  without  noise  and  dis- 
tortion. To  use  these  stages  "straight" 
without  filters  means  trouble  as  soon  as 
the  output  is  taken  from  the  second  stage 
through  the  jack  (J2).  Any  high  grade 
audio  frequency  transformer  can  be  used 
for  this  purpose.  The  ratio  of  the  first 
stage  should  preferably  be  from  3/1  to 
4/1  while  the  ratio  of  the  second  stage 
transformer  can  be  5/1  to  6/1.  Higher 
ratios  are  general  not  advisable. 

Grid  biasing  by  means  of  the  "C"  bat- 
tery is  most  essential  to  the  proper 
operation  of  the  set.  It  at  once  promotes 
clarity  of  tone  and  effects  a  saving  of  "B" 
battery  current  in  the  audio  frequency 
tubes.  For  a  plate  potential  of  90  volts, 
a  three  cell  4.5  volt  "C"  battery  will  give 
the  best  results  with  the  201A  tubes. 
There  is  no  current  drain  to  speak  of  on 
this  battery  and  it  can  be  the  smallest 
type  of  three  cell  battery  procurable. 
While  most  high  grade  audio  transformers 
are  well  shielded,  yet  it  is  safest  to  place 
them  at  right  angles  to  one  another  as 
shown  in  Fig.  2.  This  eliminates  any 
danger  of  noise  or  interference. 

Two  fixed  condensers  are  connected 
across  the  primary  and  secondary  of  the 
first  stage  audio  transformer  (ATI). 
Condenser  (K4)  has  a  capacity  of  0.00025 


mf.  while  (K8)  is  a  0.001  mf.  size. 
Another  filter  fixed  condenser  (K4)  is 
connected  between  the  grid  (G)  and  the 
(— )  post  of  the  "C"  battery  at  (K4)  and 
has  a  capacity  of  0.00025  mf.  This  com- 
pletes the  audio  frequency  stages  except 
for  the  three  jacks  (JD-J1-J2)  which  are 
interconnected  with  the  stages  as  shown. 

The  Loop  Connections 

At  the  extreme  upper  right  hand  corner 
of  the  panel  in  Fig.  2  are  the  two  binding 
posts  for  the  loop  connection.  It  is  best 
to  use  binding  posts  and  to  avoid  the 
use  of  a  jack  at  this  point  as  a  jack  in- 
troduces objectionable  capacity  into  the 
circuit  and  also  permits  of  some  leakage 
of  the  already  weak  radio  impulses.  As 
explained,  the  set  is  somewhat  more  sen- 
sitive and  selective  if  the  lower  binding 
post  is  grounded,  or  if  the  (+A)  line  is 
grounded.  This  ground  can  be  made 
directly  from  the  post  or  from  some  more 
convenient  point  in  the  circuit  as  at  the 
(+A)  binding  post.  This  effect  is  parti- 
cularly noticeable  in  cities  where  the 
radio  traffic  is  congested  and  where  the 
utmost  in  selectivity  is  necessary. 

In  regard  to  the  "B"  batteries  it  must 
be  noted  that  the  demand  for  plate  cur- 
rent is  very  heavy  and  that  for  the  best 
service  a  storage  "B"  battery  is  highly 
desirable.  If  a  storage  "B"  is  out  of  the 
question  with  the  user,  then  only  the 
largest  size  of  dry  batteries  are  advisable. 
The  eight  tubes  will  run  down  a  small  or 
medium  size  "B"  battery  in  a  very  short 
time  and  in  the  end,  the  smaller  dry  cell 
batteries  will  prove  much  more  expensive 
than  storage  batteries  or  large  dry  bat- 
teries. A  full  90  volts  should  be  main- 
tained at  all  times  for  the  maximum  out- 
put, and  much  of  the  trouble  experienced 
with  super- heterodynes  can  be  traced  to 
exhausted  "B"  batteries  which  have  been 
allowed  to  outlive  their  usefulness. 

At  the  left  of  the  baseboard  will  be 
seen  the  terminal  strip  of  bakelite  on 
which  the  battery  binding  posts  are 
mounted.  This  is  1  1/4  inch  wide  and  6 
inches  long  with  a  thickness  of  3/16  inch. 
Wires  to  the  connections  run  off  through 
the  side  or  back  of  the  cabinet,  and  this 
makes  a  much  neater  arrangement  than 
with  the  binding  posts  mounted  on  the 
front  of  the  panel  as  we  sometimes  see 
such  sets.  Spacers  are  placed  beneath 
the  terminal  strip  to  raise  it  well  above 
the  bottom  board  and  so  that  the  screw 
heads  will  not  make  contact  with  the 
wooden  bottom  board.  Wood  is  not  a 
perfect  insulator  and  therefore  we  should 
avoid  placing  any  current  carrying  parts 
in  contact  with  it. 

While  spaghetti  can  be  used  with 
profit  on  all  "A"  battery  and  ground 
wires,  its  use  is  not  advised  on  wiring 
which  carries  radio  frequency  currents, 
except  at  points  where  a  short  length  is 
necessary  to  prevent  actual  short  circuits. 
Spaghetti  has  a  high  dielectric  value  and 
increases  the  capacity  of  the  circuits 
with  attending  losses. 

1  T  GOES  without  saying  that  all  joints 
■*-  must  be  soldered  and  that  particular 
care  must  be  taken  where  soldered  con- 
nections are  made  to  the  jacks.  Rosin 
flux  must  be  used  exclusively  (no  acid) 
and   in    using   the   rosin    one   must   take 


care  that  the  parts  are  actually  soldered 
and  not  simply  stuck  together  with  the 
non-conducting  rosin  flux.  After  solder- 
ing, shake  the  wire  vigorously  to  make 
certain  that  the  parts  are  soldered.  In 
such  a  complicated  set,  it  is  exceeding 
difficult  to  trace  trouble  when  due  to 
open  joints,  hence  we  must  be  vigilant 
during  the  wiring  operations. 

Tubes  should  be  matched  by  the 
dealer  so  that  all  of  the  radio  frequency 
tubes  are  electrically  identical.  If  this 
is  not  done,  then  it  will  be  impossible 
to  secure  maximum  amplification  in  the 
radio  stages.  Much  of  the  success  with 
a  super-heterodyne  circuit  depends  upon 
the  accuracy  with  which  the  transformers 
are  matched  and  their  agreement  with 
the  tubes.  When  the  transformers  are 
successively  numbered  from  the  input 
through  to  the  output  transformer,  they 
must  then  be  arranged  in  numerical 
order  as  shown  by  RD-1,  RD-2,  RD-3 
and  RD-4. 

For  the  convenience  of  the  builder 
the  "A"  and  "B"  battery  connections 
are  made  according  to  two  different 
systems.  In  Fig.  1  the  negative  "B" 
(  — B)  is  connected  to  the  positive  "A" 
(+A),  and  in  general  this  will  give  the 
best  results.  The  connections  can  be, 
seen  at  the  extreme  right  of  Fig.  1  at 
the  terminals.  However,  under  certain 
conditions  it  is  better  to  connect  (—A) 
to  (  —  B)  as  in  Fig.  2.  Either  connection 
is  easily  had  without  labor  by  changing 
the  cross  connection  or  "jumper  wire" 
at  the  terminal  board.  In  the  first  case, 
the  jumper  in  Fig.  1  runs  from  the  (  — B) 
terminal  to  the  (+A)  terminal.  In  Fig. 
2  this  is  switched  from  (+A)  so  that  the 
(— B)  terminal  is  connected  to  the 
(—A)  terminal.  This  is  simple,  and  we 
should    try   out   to    find    which    is   best. 

In  connecting  the  ammeter  and  volt- 
meter, we  must  observe  the  polarity 
marked  on  these  instruments;  that  is, 
the  wire  from  the  positive  bus  must  go 
to  the  positive  terminal  of  the  instru- 
ments. If  these  connections  are  reversed, 
then  the  instruments  will  have  the  needle 
come  to  rest  on  the  zero  stop  and  will  not 
indicate  the  current  or  voltage.  In 
connecting  up  the  transformers,  the 
marks  on  the  transformer  posts  should 
be  observed,  the  grid  (G)  on  the  trans- 
former being  connected  to  the  grid  (G) 
of  the  socket  as  shown  in  both  Figs.  1-2. 

Particular  care  should  be  taken  to 
connect  up  the  variable  condensers  so 
that  the  connections  between  the  grid 
of  the  tube  and  the  stator  (stationary 
plates)  are  always  observed.  If  the  grid 
is  connected  to  the  rotor  or  movable 
plates,  then  we  will  have  trouble  from 
body  capacity  effect,  as  the  full  grid 
potential  is  then  carried  out  to  the  hands 
through  the  condenser  shaft.  The  proper 
connections  are  clearly  shown  in  Fig.  2. 

In  order  to  absorb  undesirable  vibra- 
tions from  the  radio  stages,  a  grid  leak 
(1  megohm)  is  connected  across  between 
the  negative  of  "C"  and  the  grid  of  the 
last  audio  tube  so  that  the  leak  (GL) 
and  the  condenser  (K2)  form  the  con- 
ventional grid  leak  and  condenser.  This 
has  a  notable  effect  in  reducing  noise 
when  the  second  stage  of  audio  is  thrown 
in.  The  negative  of  the  "C"  battery 
must  go  to  the  grid   (G)  as  shown. 


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RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour  85 


WITHJ[ 


Silver  Super  Wins  Grand  Prize 
at  Los  Angeles  Show 

Against  a  field  of  more  than  400  set- 
builders,  including  scores  of  radio  ex- 
perts and  engineers,  an  18-year-old 
builder  of  a  Silver  Super-Heterodyne 
carried  away  first  honors  in  the  Grand 
Sweepstake  Contest  conducted  at  the 
National  Automotive  School  Radio  Show 
in  Los  Angeles,  June  7. 

The  prize  was  a  $300  cash  award, 
offered  for  the  finest  set  in  the  entire 
contest,  which  was  held  in  conjunction 
with  the  radio  show.  The  youthful 
winner  was  Robert  Haig,  of  8123  Norton 
Ave.,  West  Hollywood,  Calif.,  and  the 
super-hete'^dyne  with  which  he  won  the 
grand  prize  was  built  from  the  circuit 
developed  by  McMurdo  Silver,  Assoc, 
I.  R.  E.,  whose  work  in  super-heterodyne 
and  transformer  development  is  nation- 
ally known  and  recognized.  Silver- 
Marshall  super  parts,  also  developed 
and  designed  by  Mr.  Silver,  were  used 
exclusively  in  Mr.  Haig's  prize  receiver. 

The  award  was  judged  on  distance, 
quality  of  tone  and  selectivity,  by  three 
of  the  best  informed  radio  engineers  and 
editors  in  the  industry.  The  set  was  a 
portable  model  Silver-Super,  a  seven- 
tube   outfit   on   a    7"   by    18"   panel. 

Of  the  total  of  432  sets  entered  in  the 
contest,  eighty-three  were  super-hetero- 
dynes, built  by  some  of  the  best  known 
super-heterodyne  experts  in  the  country. 
More  than  40,000  radio  fans  attended 
the  exhibition. 

In  thanking  the  judges  for  the  grand 
prize,  yo  jng  Haig  said: 

"I  have  built  more  than  10  supers,  but 
I  found  the  Silver-Super  the  very  best 
I  ever  built  and  it  is  beating  every  set 
in  town  for  reaching  out  and  bringing  in 
the  distant  and  hard-to-get  stations.  It 
is  easy  to  tune,  selective,  the  locals 
never  bother  me,  and  it  was  easy  to  build. 
The  parts  and  circuit  are  all  Silver- 
Marshall,  and  I  feel  I  have  the  best- 
performing  set  on  the  Pacific  Coast. 
I  had  no  trouble  in  building  it.  I  simply 
followed  the  instructions  with  parts  I 
had  bought,  and  after  hooking  it  up,  it 
worked  perfectly." 


Fada  Radio,  Limited,^ 
Announcement 

A  Canadian  Corporation  has  been 
formed  under  the  name  of  Fada  Radio 
Ltd.,  at  821-827  Queen  Street,  E.  Toron- 
to, Canada.  The  officers  of  this  company 
are  as  follows:  President  and  Treasurer, 
Frank  A.  D.  Andrea;  Vice-President, 
Concetta  Andrea;  Secretary,  R.  M. 
Klein;  Manager,  C.  R.  Fraser;  Superin- 
tendent, T.  M.  Rozelle. 

This  Canadian  Company  is  licensed 
under  the  Canadian  Hazeltine  patents 
in  conjunction  with  F.  A.  D.  Andrea, 
Inc.,  of  New  York  City,  to  manufacture 
a  complete  line  of  Fada  Neutrodyne 
Receivers. 


Stemm  Assumes 
Duties 


New 


Royal  A.  Stemm,  who  has  for  the  last 
two  and  a  half  years  been  the  Illinois 
representative  for  the  Crosley  Radio 
Corp.  has  tendered  his  resignation  to  this 
company,  effective  June  the  first,  and  will 
immediately  assume  his  duties  as  Presi- 
dent of  the  Jackson  Sales  Company,  20 
East   Jackson    Boulevard,    Chicago. 

Mr.  Stemm  has  been  intimately 
associated  with  radio  in  its  various 
phases  since  its  first  inception  as  a  com- 
mercial product  and  has  always  forcibly 
and  effectively  played  his  part  along 
the  tangents  that  are  for  the  betterment 
of  radio  and  its  merchandising  problems. 
"Royal",  as  he  is  known  among  his  inti- 
mates, has  by  his  energetic  and  pleasing 
personality  won  a  large  coterie  of  friends, 
both  in  the  social  and  business  world  of 
radio. 

The  many  messages  of  congratulations 
and  good  wishes  already  received,  demon- 
strate his  popularity  in  the  trade  and 
it  is  predicted  that  in  his  new  and  larger 
fields  of  activity,  he  will  be  much 
heard  of  throughout  the  middle  west 
territory. 

The  Jackson  Sales  Company,  which 
was  organized  over  a  year  ago,  are  the 
exclusive  Manufacturer's  representa- 
tive of  the  well  known  Air  Way  Receivers 
for  the  States  of  Illinois,  Wisconsin, 
Minnesota,  the  Dakotas  and  the  upper 
peninsula  of  Michigan.  They  also  repre- 
sent the  Wireless  Dry  Cells  Ltd.,  Niagara 
Falls,  manufacturers  of  Maximite  "A," 
"B,"  and  "C"  Batteries,  and  operators  of 
Station  CKCL  Toronto;  The  Shamrock 
Manufacturing  Company,  Newark,  N. 
J.;  The  Inter-Ocean  Radio  Corp.,  manu- 
facturers of  Woodehorn;  Niles  Manu- 
facturing Company,  manufacturers  of 
the  Niles  chargers;  and  several  other 
well    known   lines. 


New  "B"  Battery 
Charger 

The  Apco  Manufacturing  Company, 
makers  of  the  well  known  line  of  Apco 
Battery  Chargers  and  other  Radio 
products,  announce  a  new  "B"  Battery 
Charger,  that  is  a  radical  departure  from 
anything    heretofore    manufactured. 

It  is  a  combination  electric  light  bulb 
and  vibrator  type,  which  charges  either 
a  24,  48  or  96  volt  battery  at  from  1-10 
to  1-4  of  an  ampere,  depending  on  the 
size  of  the  lamp  used,  which  is  an  or- 
dinary electric  light  bulb  of  25  to  ISO 
watt  capacity. 

The  manufacturers  claim  that  this  is 
the  only  Battery  Charger  made  that 
will  charge  100  volts  at  one  time  in  10 
hours,  at  a  cost  so  insignificant  that  it  is 
hardly  measurable. 

The  device  sells  for  $4.00,  and  complete 
data  will  be  sent  by  the  manufacturer 
on  request. 


Signal  Holds  Sales 
Conference 

The  annual  sales  conference  of  the 
Signal  Electric  Manufacturing  Company, 
of  Menominee,  Michigan,  was  held 
May  18th-22nd.  Twenty-one  represen- 
tatives from  all  over  the  United  States 
and  Canada  were  brought  to  the  factory 
for  five  days  of  business  and  pleasure. 
Business  in  the  morning,  fishing,  boating 
and  dancing  in   afternoon   and   evening. 

Before  the  conference  opened  the  rep- 
resentatives took  a  tour  through  the 
factory,  which  covers  42,380  square  feet 
of  floor  space,  and  were  shown  how  Sig- 
nal Quality  Products  were  manufactured 
and  each  one  assembled  a  Signal  Jr. 
Fan,  which  has  proved  a  big  winner  this 
year. 

The  conference  was  called  to  order 
at  10:00  a.  m.  by  Charles  E.  Hammond, 
general  manager,  and  first  expressed  his 
appreciation  for  the  good  work  "The 
Boys"  had  done  during  the  past  year. 
He  next  introduced  William  E.  Hopper, 
the  newly  appointed  sales  manager. 

The  present  items  of  the  line  were 
first  discussed  and  then  the  new  ones 
were  introduced.  These  newly  introduced 
items  were  received  with  great  enthu- 
siasm and  the  unanimous  opinion  of 
sales  force  was  that  "Signal  Would 
Enjoy  Wonderful  Business"  on  all  its 
lines,  but  especially  on  the  new  items, 
which  are  "world  beaters." 

The  new  items  introduced  were:  a 
new  loop,  variable  condenser,  a  complete 
line  of  A.  C.  and  D.  C.  bells,  exhaust 
fans,  new  bell  ringing  transformer,  fac- 
tory siren  Signal,  and  newly  designed 
cabinets. 


"Clearco  Crystal" 
Ready 

One  oi  the  most  unusual  endorsements 
ever  given  an  accessory  has  just  been 
put  into  practice  by  the  Howe  Auto 
Products  Company,  which  now  are 
including  with  each  Howe  Radio  Re- 
ceiver a  special  card  relating  to  the 
Clearco  Crystal,  which  has  been  adopted 
as  standard  for  Howe  Sets.  The  card 
states: 

"This  Howe  Radio  Receiver  is  equipped 
with  a  Clearco  Crystal,  adopted  as 
standard  for  Howe  Sets  after  exhaustie 
tests.  It  is  highly  sensitive  and  hot 
everywhere.  We  highly  recommend  this 
crystal.  The  continued  use  of  Clearco 
Crystals  in  your  Howe  Set  will  give  you 
the  best  possible  reception.  If  your 
dealer  does  not  handle  Clearco  Crystals, 
have  him  write  direct  to  the  Clearco 
Crystal  Co.,   Idaho  Springs,   Colo." 

The  card  shows  upon  its  reverse  side 
the  towering  peaks  of  the  Rocky  Moun- 
tains in  the  vicinity  of  Idaho  Springs, 
Colorado,  where  the  mineral  which  goes 
into  the  making  of  Clearco  Crystals 
is  mined.  The  spot,  incidentally,  is 
(Turn  to  page  90) 


€6  RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


ment  in  the  form  of  two  fifty  watt  tubes. 
Previous  oscillators  had  been  made  to 
operate  on  four  or  five  meters,  but  it  had 
been  necessary  to  eliminate  the  tube 
sockets  and  remove  the  bases.  It  was 
also  necessary  to  nullify  the  tube  capa- 
city. Redington's  form  of  oscillator 
makes  use  of  the  internal  capacity,  and 
by  the  use  of  extremely  short  leads  be- 
tween the  sockets,  he  was  able  to  make 
the  set  oscillate  at  3.8  meters. 


^TT  Write  the  Pickups  and 
99  I  Hookups  editor  and  tell 
^^*fchim  what  you  are  doing 
to  eliminate  static. 


Fig.  5.  (above)  Browning  Drake  adaptation, 

using  4  UV199's,  the  fifth  in  parallel  with 

the  fourth  tube. 

Fig.  6  (at  right).  The  veins  on  Mr.  Cox's 
hand  do  not  stand  out  unduly,  so  we  assume 
the  Self-contained  set  must  not  weigh  very 
much.  And  weight  is  something  which  a 
traveling  man  doesn  t  like  plenty  of. 

(Continued  from  page  22) 

fading  and  strength  of  signals  on  differ- 
ent  wavelengths. 


Edmund  B.  Redington,  of  Waverly, 
N.  Y.,  a  senior  in  the  class  of  1925  at 
Union  College,  has  been  awarded  the 
Bailey  Prize  given  each  year  for  the 
senior  who  contributes  most  to  the  ad- 
vancement  of   the   college. 

Redington's  work  was  the  operation  of 
a  radio  transmitter  on  3.8  meters.  This 
was  accomplished  using  standard  equip- 


¥ig.  7.     Here  is  the  set  we  mentioned  previously  which  P.  E.  Chapman  uses  while  canoeing.     It  is  an  ultra-audion  arrangement 

with  two  stages  of  audio,  using  "199"  tubes. 


RADIO  AGE /«?/•  August,  1925 

Standard  Radio  Receivers 

Recently  RADIO  ACE  inaugurated  a  new  department  called  "Know  Before 
You  Buy,"  to  serve  as  a  guide  to  the  prospective  radio  purchaser  in  deciding 
on  the- receiver  best  suited  to  his  individual  needs.  Fans  throughout  the 
country  have  shown  an  instantaneous  response  to  this  new  feature,  and  accord- 
ingly it  is  continued  and  will  be  a  feature  of  all  forthcoming  numbers  of  RADIO 
ACE.  Readers  are  invited  to  write  us  concerning  the  sets  in  which  they 
are  interested,  and  manufacturers  also  are  asked  to  send  us  material  describ- 
ing their  sets. 


Tie  Magazine  of  the  Hour 


87 


IN  TESTING  the  Melco  Supreme  re- 
ceiver we  experienced  a  few  new 
things,  both  in  circuit  design  and 
use  of  radio  apparatus.  The  Melco 
Supreme  receiver  is  a  tuned  radio- 
frequency  receiver  using  five  tubes,  and 
follows  the  usual  design  in  such  a  circuit. 
The  differences  that  exist  are  not  in  any 
way  radical  but  they  represent  refine- 
ments in  parts  of  the  circuit  that  are  im- 
portant. 

The  engineers  of  the  circuit  have 
used  a  variable  inductance  in  places 
of  the  customary  variable  capacity  and 
fixed  inductance  combination  that  is 
used  so  much  in  this  type  of  receiver. 
The  advantage  in  substituting  a  variable 
inductance  in  place  of  the  customary 
condenser  and  coil  combination  lies  in  the 
greater  amplification  of  the  radio-fre- 
quency energy  given  by  the  use  of  a, 
large  grid  inductance.  We  have  not  seen 
much  in  the  line  of  variable  inductance 
tuned  radio-frequency  receivers  because 
there  are  many  peculiar  obstacles  that 
present  themselves  when  a  high  induc- 
tance is  used  in  the  grid  circuit.  The 
most  pronounced  of  the  drawbacks  is 
the  straying  of  magnetic  fields  from 
one  stage  to  another.  A  feature  of 
the  Melco  Supreme  inductances  is  the 
confinement  of  each  field  to  its  respective 
inductance. 

"D"  Shaped  Coils  Used. 

This  is  accomplished  by  splitting 
the  inductance  in  two  D  shaped  coils, 
both  mutually  connected  to  form  one 
continuous  connection,  but  the  mag- 
netic lines  of  force  so  travel  that  they 
are  attracted  to  one  another  and  self- 
confined.  The  path  presented  between 
the  two  coils  of  each  stage  is  of  much 
less  resistance  than  the  path  offered  from 
stage  to  stage  for  promotion  of  magnetic 
straying  from  one  stage  to  another. 

The  prevention  of  stray  magnetic 
fields  is  highly  desirable  if  reception  is 
wanted,  unaccompanied  by  whistles  and 
howls.  To  prevent  the  impairing  of 
reception  by  whistles  and  howls  the 
Melco  receiver  has  two  auxiliary  ad- 
justments that  are  designed  for  the  sole 
purpose  of  allowing  maximum  amplifi- 
cation of  the  received  signal  without 
interference  by  whistles  and  howls  thru 
oscillation.  Oscillation  is  generally  ex- 
perienced when  the  three  main  tuning 
c'ials   are   tuned   to   resonance    with    the 


frequency  of  an  incoming  signal.  If  the 
set  is  designed  to  give  great  amplification 
it  often  will  burst  into  a  shrill  whistle  as 
exact  resonance  is  reached.  It  is  both 
desirable  to  obtain  great  amplification 
of  the  signal  and  a  resonant  tuning 
condition  but  it  is  impracticable  to  re- 
ceive a  signa'  under  such  a  condition 
without  promoting  the  oscillation  an- 
noyance. 

Oscillation  Control. 

The  Melco  Supreme  receiver  employs 
a  method  of  controlling  oscillation  by 
allowing  exact  tuning  to  resonance  and 
controlling  the  amplification  of  the 
signal  to  a  point  that  lies  just  below 
the  point  where  oscillation  takes  place. 
This  is  done  thru  the  manipulation  of 
two  small  dials  that  are  situated  a 
little  above  the  center  line  axis  of  the 
three  main  wave  length  tuning  controls. 

Reception  of  distant  stations  is  made 
more  easy  by  the  use  of  these  dials 
by  allowing  the  two  oscillation  con- 
trols to  remain  in  an  oscillatory  con- 
dition. The  incoming  signal  is  no- 
ticed by  the  oscillation  whistle.  When 
once  the  station  is  located  the  two 
controls  may  be  adjusted  to  a  point 
below  the  oscillation  point  and  the 
signal  will  be  freed  from  any  inter- 
ference caused  from  the  oscillation. 

Spacing  of  Parts. 

Maximum  spacing  of  the  sensitive 
parts  of  the  circuit  is  obtained  by  con- 
structing the  set  with  the  stage  sockets 
in  the  following  order:  (1)  Second  audio 
stage;  (2)  First  radio  stage;  (3)  Second 
radio  stage;  (4)  First  audio  stage; 
(5)   Detector  stage. 

Spacing  the  first  audio  stage  be- 
tween the  second  radio  and  the  de- 
tector stage  keeps  the  detector  stage 
sufficiently  far  away  from  the  radio 
stages  to  minimize  any  tendencies  for 
the  detector  tube  to  oscillate  or  regen- 
erate. If  this  were  not  corrected  in 
this  manner  it  wou'd  probably  be 
necessary  to  use  an  additional  oscilla- 
tion control  to  retard  regeneration. 
By  arranging  the  parts  as  specified 
regeneration  is  eliminated  before  it  is 
created  and  the  additional  control  is 
made  unnecessary. 

The  Melco  Supreme  receiver  is  a 
handsome  instrument  possessing  a  most 
pleasing   balance    of    operating   controls 


Earn  $100  a 
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in  Radio 

THOUSANDS  of  Radio  Experts  are  needed 
to  design,  repair,  maintain,  sell  radio  appara- 
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scores  of  other  big  paying  radio  jobs. 

And  now,  you  can  easily  become  a  Radio  Expert. 
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vidual help  by  mail.     Training  Guaranteed. 

Free  Employment 
Service 

Hardly  a  week  goes  by  witliout  our  receiving 
urgent  calls  for  our  graduates.  "We  iieed  a  com- 
petent Radio  Engineer" — "We  want  men  with 
executive  ability  in  addition  to  radio  knowledge 
to  become  our  local  managers" — "We  require  the 
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of  opportunities  open  to  our  graduates. 

Receiving  Set  and 
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Our  course  of  practical  instruction  includes 
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Name Age „ 


Street.. 
City 


ss 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


Majestic  Roll 

of  the 

Mighty  Or^an 

Mighty  tones  from 
the  depths  of  the 
noblest  of  musical  in' 
struments  do  not  tax 
the  resources  of 
Rauland'Lyric.  Ac 
curately  designed  for 
faultless  amplifica' 
tion,  this  instrument 
faithfully  transmits  all 
organ  tones  —  those 
of  the  piccolo  stop  as 
well  as  those  of  the 
open  diapason. 


Rauland- Lyric  is  a  laboratory- 
grade  audio  transformer  de- 
signed especially  for  music 
lovers.  The  price  is  nine  dollars. 
Descriptive  circular  with  am- 
plification curve  will  be  mailed 
on  request.  Ail-American 
Radio  Corporation,  4201  Bel- 
mont Ave.,  Chicago. 


TRADF  MARK  ^ 

fANSFORMEI 

T/ie  Choice  of  Noted  Music  Critics 


TRANSFORMER  |fi| 


THE    RADIO    AGE 
BUYERS'    SERVICE 

What  do  you  want  to  purchase  in  the  radio  line?  Let  the  staff  of  RADIO  AGE  save  you 
time  and  money  by  sending  in  the  coupon  below.  Enter  the  number  of  the  article  you 
would  like  to  know  more  about  in  the  spaces  provided  in  the  coupon. 


1  "A"  Batteries 

2  Aerial  protector. 

3  Aerial  insulators 

4  Aerials 

5  Aerials.  loop 

6  Amplifiers 

7  Amplifying  units 

8  Ammeters 

9  "B"  batteries 

10  Batteries    (state  voltage) 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery  substitutes 

17  Bezels 

18  Binding  poBts 

19  Binding  posts,  insulated 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatstone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisers 

33  Coils 

34  Coils,  choke 

35  Coils,  coupling 

36  Coils,  filter 

37  Coils,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance 

40  Coils,  Reinartz 

41  Coils,  stabilizer 

42  Coils 


■  parts 
-s,  antenn 


pho 


s.  fixed  (paper, 


43  Co 

44  Co 

45  Co 
ling 

46  Conde 

47  Conde 

48  Conde 

49  Conde 

50  Conde 

51  Condensers,  variable  mi 

52  Condensers,  vernier 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  sets 

57  Couplers,  looSe 

58  Couplers,  molded 

59  Couplers,  vario 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 

71  Dial,  adjusters 

72  Dials,  composition 
hard  rubber 
rheostat 


vith  kn 


73  D 

74  Dial 

75  Dial 

76  Dial 

77  Dial, 

78  Dies 

79  Drills,  electric 

80  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

83  Enamels,  battery 

84  Enamels,  metal 

85  End  stops 

86  Eyelets 

87  Experimental  work 

88  Fibre  sheet,  vulcanize: 

89  Filter  reactors 

90  Fixtures 

91  Fuse  cut  outs 

92  Fuses,  tube 

93  Generators, high  frequ 

94  Grid  choppers,  rotary 


95  Grid  leak  holders 

96  Grid,  transmitting  leaks 

97  Grid  leaks,  tube 

98  Grid  leaks,  variable 

99  Grinders,  electric 

100  Ground  clamps 

101  Ground  rods 

102  Handles,  switch 

103  Head  bands 

104  Head  phones 

105  Head  sets 

106  Honeycomb  coil  adapter! 

107  Hook  ups 

108  Horns,  composition 

109  Horns,  fibre 

110  Horns,  mache 

111  Horns,  metal 

112  Horns,  wooden 

113  Hydromete 


es,  C.  W. 
,  molded 


ulator; 
ulator; 
ulator: 
ulator 
ulator: 
ulator. 


fibre 
high  v 
cloth 


.ltage 


hard  rubber 


,  testii 


114  ... 

115  Ind 

116  Ins. 

117  In 

118  In 

119  In 

120  In 

121  In 

122  In 

123  In 

124  Insulatoi 

125  Insulatoi 

126  Irons,  so 

127  Jacks 

128  Filamenl 

129  Jars,  bat 

130  Keys,  tr» 

131  Knobs 

132  Knock-d 

133  Laboratc 

134  Lever,  switch 

135  Lightning  arr< 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  ' 

139  Lugs,  battery 

140  Lugs,  termina 

141  Measuring  ins 

142  Megohmeters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeten 

148  Minerals 

149  Molded  insula 

150  Molybdenum 

151  Mountings,  co 

152  Mountings. 
leak 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,  honeycor 
coil 

156  Mountings,      inducta 
switch 

157  Name  plates 

158  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeters 

161  Oscillators 

162  Panel  cutt 

163  Panels,     d 
drilled 

164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  Boldering 

168  Patent  attorneys 

169  Phone  connectors,  mu 
pie 

170  Phonograph  adapters 

171  Plates,  condenser 

172  Plugs,  coil 

173  Plugs,  telephone 

174  Pointers,  dial  and  kno 

175  Poles,  aerial 

176  Potentiometers 

177  Punching  machines 

178  Reinartz  set  parts 
l^  Regenerative  set  parts 

180  Receiver  caps 

181  Rectifiers,  battery 

182  Resistance  leaks 

183  Resistance  units 

184  Rheostat  bases 

185  Rheostat  strips 


ndens 


rilled 


nd  drilling 


186  Rheostats,  automatic 

187  Rheostats,  battery 

188  Rheostats,  dial 

189  Rheostats,  filament 

190  Rheostats,     potentiometer 

191  Rheostats,  power 

192  Rheostats,  vernier 

193  Rods,  ground 

194  Rotors 

195  Scrapers,  wire 

196  Screwdrivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving— cabinet 

200  Sets,  receiving — crystal 

201  Sets,     receiving— knock- 

202  Sets,     receiving  —  Neutro- 
dyne 

203  Sets,  receiving — portable 

204  Sets,   receiving — radio   fre- 
quency 

205  Sets,     receiving— reflex 

206  Sets,    receiving — regenera- 

207  Sets,   receiving — Reinartz 

208  Sets,  receiving — sectional 

209  Sets,  receiving — shortwave 

210  Sets,     receiving — super-re- 
generative 

211  Sets,  transmitting 

212  Slate 

213  Shellac 

214  Sliders 

215  Socket  adapters 

216  Sockets. 

217  Solder 

218  Soldering  irons,  electric 

219  Soldering  paste 

220  Solder  flux 

221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 

226  Stamping. 

227  Stators 

228  Stop  points 

229  Switch  arms 

230  Switch  levers 

231  Switch  points 

232  Switch  Btops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switches, 

237  Switches. 

238  Switches, 

239  Switches, 
ble  throw 

240  Tone  who 

241  Towers,  a: 

242  T.-anslorn 


snel 

ngle  and  dou 

ial 


ncy 


forn 


243  Tra 

244  Tra: 

245  Tranafor 

246  Transfer: 

247  Transfer 

248  Tranafor: 

249  Transmil 

250  Tubes,  v: 

251  Tubes,    v 

252  Tubes,  v« 
ment 

253  Tur 

254  Var 

255  Var 

256  Var 

257  Vari 

258  Variometers, 

259  Variometers, 

260  Varnish,  insc 

261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 

265  Wir. 


ouple 
ouple 
ouple 


,  filament 
,  modulation 

,   push-pull 
,     radio     fre 


hard  rubber 

molded 

wooden 
lard  rubber 
nolded 


266  Wir 

267  Wir. 

268  Wir. 

269  Win 

270  Wir. 

271  Wir. 

272  Wir. 


.[braided  and  stranded 


RADIO   AGE   BUYERS'  SERVICE,  500   N.  Dearborn  St.,  Chicago,  III. 

Please  see  that  I  am  supplied  with  buying  specifications  and  prices  on  the  articles  numbered  herewith: 


I  I  I 


I  I  I  1 


I  am  a —  Q  Dealer             ^}   Jobber             "2    Mfgrs.'   Rep.           □    Manufacturer 
Firm      [If   identified   with  Radio  industry]    _ 

My    Name    _ - — - - 


City 


_.,    State    _ 

¥     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  j 'or  August,  1925 


The  Magazine  of  the  Hour 


89 


Scientifically  Designed  I.  F. 
Transformers 

IT  IS  not  the  purpose  of  this  paper, 
nor  is  it  possible  in  the  space  avail- 
able, to  enter  into  a  theoretical  con- 
sideration of  the  ideal  characteristics  of 
intermediate  frequency  inter-stage  trans- 
formers suitable  for  use  in  super-hetero- 
dyne receiving  systems,  but  rather  to 
explain  the  desirable  characteristics  of 
such  transformers  briefly,  and  to  present 
some  designs  which  have  been  found 
most  satisfactory,  yet  simple  enough  to 
be  constructed  by  the  experimentally 
inclined    radio    enthusiast. 

As  is  well  known,  a  signal  received 
upon  a  super-heterodyne  system  at  a 
short  wavelength  is  converted  by  means 
of  an  oscillator  and  first  detector  to  some 
longer  wavelength,  then  fed  to  a  sharplv 
tuned  amplifier,  amplified,  and  again 
detected,  after  which  the  audio  frequency 
signal  may  be  further  amplified.  The 
reason  for  this  change  in  wavelength 
is  two-fold:  Direct  radio  frequency 
amplification  at  short  wavelengths  is 
not  at  all  efficient,  whereas  it  may  be 
made  extremely  so  at  longer  waves 
between  two  and  ten  thousand   meters. 

The  second  reason  is  that  an  efficient 
radio  frequency  amplifier  operating  at 
broadcasting  wavelengths  must  have 
each  stage  tuned,  which  would  involve 
from  three  to  six  adjustments  for  a  really 
sensitive  receiver  (interstage  coupling 
in  the  amplifier  prevents  practically- 
building  such  a  really  sensitive  system) 
each  time  it  was  desired  to  tune  to  a 
different  signal.  In  the  super,  the  ampli- 
fier, consisting  of  several  stages,  is  per- 
manently tuned  to  one  wavelength,  and 
the  signal  wavelength  changed  to  that  of 
the  amplifier  by  means  of  but  two  adjust- 
ments— the  oscillator  and  loop  circuit 
controls,  regardless  of  the  amount  of 
amplification  obtained. 

The  Requirements 

r\BVIOUSLY,  the  ideal  interstage 
^  transformer  must  operate  at  a  wave- 
length long  enough  to  get  away  from  the 
drawbacks  of  shortwave  amplification, 
but  not  long  enough  so  that  the  amplifier 
will  verge  into  the  audio  frequency  range 
and  be  non-selective.  The  transformer 
must  give  the  greatest  possible  again 
(amplification)  so  that  a  minimum  num- 
ber of  stages  may  be  used;  it  must  be 
entirely  stable,  and  preferably  operate 
with  a  negative  grid  potential  to  be 
economical  of  plate  current.  In  its  ideal 
state,  the  transformer  would  give  uni- 
form amplification  over  a  frequency 
range  of  10,000  cycles  (necessary  for 
undistorted  speech  and  music  repro- 
duction) yet  no  amplification  of  any 
frequencies  outside  this  range.  It  must 
not  be  so  selective  as  to  cut  frequencies 
within  this  range,  and  it  should  be  so 
shielded  either  by  a  metal  case  or  an  iron 
core  that  it  will  not  be  affected  by  strays 
in  the  nature  of  long  wave  telegraph 
transmission,  etc.  This  latter  considera- 
tion necessitates  the  use  of.  a  wavelength 
not  commonly  used  for  telegraph  trans- 
mission, 

{Turn  to  page  96) 


Over  500  Stations  in  U.  S. — 
How  Many  Do  You  Get? 

The  air  is  fairly  crowded  with  an  infinite  variety  of  programs. 
Yet  most  listeners  rarely  hear  more  than  thirty  or  forty.  A 
good  set  has  the  ability  to  bring  in  practically  all  of  these  sta- 
tions, but  it  takes  fine  tuning 
to  get  them.  Almost  impos- 
sible with  ordinary  dials.  Slip- 
ping, backlashing  "Verniers" 
are  little  better. 

The  new  "BETTER  TUNING" 
Control,  solves  the  problem.  Smooth, 
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quickly  and  easily  to  that  last,  fine 
hairline  adjustment. 

Works  with  either  right  or  left  turn- 
ing instruments.  Readings  in  dial 
numbers  and  wave  lengths  or  call 
letters. 

Not  only  makes  your  set  work  bet- 
ter but  look  better. 

New  B-T  Products 

The  New  B-T  Inductance,  the  Toro- 
style    Transformer    practically    eliminates 
Patents  Pending  pick-up,  no  intercoupling. 

The  B-T  Socket,  something  new  and 
different.  Features  you'll  appreciate  on 
sight.  Write  Dept.  S  for  circulars. 

Bremer  -  Tully  mfg.  co. 

532  S.  Canal  St.  Chicago,  111. 


MARVELOUS  NEW 
AUDIO  TRANSFORMER 

adds  a  musical  qualityto  any  set  far 
beyond  anything  you  ever  beard 
before. 

KARAS  HARMONIK 
Amplifies  low,  middle  and  high 
tones — allto  the  same  big  volume, 
thus  eliminating  distortion.  Brings 
out  the  vita  harmonics  and  over, 
tones  of  music.  Price  S7.O0.  Write 
Karas  Electric  Co..    Depl.  58-93    M2N.  Rockwell  Si..  Chicago 


BAKELITE  KNOBS 

Permanently  hold  their  color  and 
finish.        Write    for    Booklet   31.    * 

BAKELITE  CORPORATION 

247  Park  Avenue,  New  York,  N.Y. 
Chicago  Office:  636  West  22d  Street 


WHERE  AN  AUDIO 

Transformer  Is  Called  for  in 

the  Blueprint  Use 
jn  r     r  AT  W     BEST   VALUES 
t  L,l  £S  1       GUARANTEED  ' 

Transformer 

From  Your  Dealer  or  Direct.  ggg&M 

FLINT  RADIO  CO.       J^^W_ 
1894  Wilson  Ave.,       Chicago '^  *"*> 


CORRECTION 

Our  new  address  is  116-118  So.  Wells 
Street,  Chicago.  Dealers  will  please 
note  this  change  when  writing  for  a 
copy  of  our  "Salespeaker." 
""  ^HUDSON-ROSS— 1 16  S.  Wells  St. 
Chicago 


*     Tested  and  Approved  by  RADIO  AGE     * 


90 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


LIFE, 
LIBERTY 

and  the  Pursuit  of 

HAPPINESS! 


You  Won't  Have 
to 

Pursue 
HAPPINESS 

You  can  have  it  right  at  your  elbow 
to  while  away  the  time  'til  old  Lady 
Static  gets  off  the  line! 

You'll  have  no  trouble  getting 
station  Z-I-F-F-S,  because  you'll 
find  it  is  always  tuned  in  to  catch 
your  funny  bone's  wavelength,  and 
is  more  ticklish  to  your  giggle  box 
than  the  finest  cat  whisker! 

ZIFFS,  Badzib's  Book  of  Art 
and  Wit,  is  the  only  humorous 
monthly  of  its  kind  on  the  market, 
and  is  crammed  full  of  the  best 
artists  and  funsters  in  the  world! 

Exclusive  Photo  Section!  Com- 
plete gallery  of  French-American 
Art  Studies  in  color!  Fifty  pages  of 
illustrations!  Pep,  Ginger,  Punch! 
ALL  FOR  TWO  BITS! 

Pick  This  Out  On 
Your  Piccolo! 

Even  tho    your  set  is  growling 

'Til  you  think  a  cat  is  howling 
And  the  music  comes  in  wailing,  hissing  snijfs. 

You  will  giggle,  grin  and  chuckle 

'Til  you  hafta  loose  the  buckle 
On  your  belt,  if  you've  the  latest  book  of  ZIFFS 

You  wouldn't  go  fishing  without 
bait,  would  you?  Well,  then,  don't 
try  to  get  Hong  Kong  on  a  stormy 
night  with  a  crystal  set,  till  you've 
put  your  John  Henry  on  the  tag 
below: 


ZIFFS, 

608  South  Dearborn, 
I   Chicago,  111. 

Dear  Badzib:  I 

•       I  got  a  radio.     I  got  Hawaii.     I  got  drowned   . 
I   out.     I  got  peeved. 

II  don't  see  nothin'  to  laugh  at,  you  big  buml   I 
Here's  two  bits.    Send  me  the  July  ZIFFS,  and 
I  will!  | 


|  They  Call  Me . 


I   And  I  live  at. . . . 


With  the  Manufacturers 


(Continued  from  page  85) 


Brooklyn  "Good  Will"  Trip 
a  Success 

Covering  9,021  miles  by  rail  and  2,500 
miles  by  automobile  on  their  "good-will 
and  industry"  trip,  the  Brooklyn  Cham- 
ber of  Commerce  made  radio  history  as 
well  as  scored  travel  and  industrial  honors 
this  year. 

Their  special  train  was  radio-equipped 
and  with  the  exception  of  one  day,  fol- 
lowing the  damaging  of  the  apparatus,  the 
members  heard  broadcasting,  in  many 
cases  of  programs  welcoming  them  to 
various  cities  or  given  otherwise  in  their 
honor,  throughout  the  United  States  and 
Canada. 

The  antenna  was  60  feet  long,  on  the 
roof  of  the  observation  car,  serving  a  five 
tube  neutrodyne  set  and  an  amplifier. 
In  addition,  a  portable  set  was  carried 
wherever  the  party  went  on  auto  trips  to 
scenic  points. 

Eric  H.  Palmer,  of  the  Freed-Eisemann 
Radio  Corporation,  member  of  the  Cham- 
ber, made  the  entire  trip,  and  reported 
excellent  reception  on  the  whole,  con- 
sidering the  conditions,  particularly  of 
the  high-power  stations  like  KDKA, 
WHT,  KGO,  KOA,  WON,  and  WSAI, ' 
sometimes  when  the  train  was  going  a 
mile  a  minute,  with  occasional  fading  on 
sharp  turns  and  marked  fading  in  tunnels 
and  when  crossing  steel  bridges. 

Palmer  took  his  set  into  the  Grand 
Canyon,  to  the  top  of  Pike's  Peak,  into 
Yosemite  Valley,  besides  Lake  Louise  and 
on  the  snow-covered  mountains  of  the 
Canadian  Rockies,  among  Indian  pueblos 
of  the  Southwest,  on  the  shores  of  the 
Pacific  Ocean,  and  along  the  auto  roads 
of  California,  never  failing  to  receive 
music  from  the  ether. 


Double  Service  Tube  on  the 
Market 

A  tube  with  double  service  is  announced 
by  the  Van  Home  Co.,  at  Franklin,  Ohio, 
this  concern  being  the  manufacturers  of 
the  Van  Home  Selected  and  Musselman 
Certified  radio  tubes. 

The  new  tube  is  known  as  the  3V-A 
radio  tube  and  is  adaptable  either  to  dry 
cell  or  storage  battery  operation.  It  has 
the  same  structural  principle  as  the  SV-A, 
which  is  patterned  after  the  conventional 
201-A.  It  consumes  one  quarter  of  the 
current  of  a  201-A. 

The  5V-A  tube  is  of  the  5  volt  type 
with  a  current  consumption  of  one  quar- 
ter of  an  ampere,  while  the  3V-A  takes 
three  volts  and  consumes  one  tenth  of  an 
ampere.  The  mutual  conductance  on 
the  3V-A's  is  500  micro-mhos;  the  plate 
flow  3.8  milliamperes  to  5  milliamperes 
and  the  amplification  6.5. 

With  each  of  the  certified  tubes  sold, 
Musselman  furnishes  a  characteristic 
curve  of  the  tube  itself,  a  scheme  which 
is  rapidly  finding  favor  with  the  radio 
public.  Thus  you  have  matched  trans- 
formers and  then  matched  tubes.  The 
characteristic  curve  on  each  tube  enables 
you  to  determine  its  ability  to  perform  in 
different  parts  of  the  circuit,  and  saves  the 
trouble  of  having  to  have  a  curve  drawn 
on  all  your  tubes. 
*     Tested  and  Approved  by  RADIO   AGE     * 


Voices  of  the  World  to  Be 
at  "World's  Fair" 

NEW  YORK— Plans  now  afoot  by 
leading  broadcasting  interests  in  the 
United  States,  who  will  exhibit  at  the 
Fourth  Annual  National  Radio  Exposi- 
tion, opening  in  Grand  Central  Palace, 
New  York,  September  12,  will  create  in 
the  Exposition  auditorium  a  new  tower 
of  Babel  in  which  the  voices  of  the  world 
will  be  received  by  radio,  according  to  an 
announcement  by  Harold  Bolster  and 
J.  C.  Johnson,  directors  of  the  Exposition. 

Through  the  broadcasting  studios  and 
receiving  station  to  be  set  up  in  Grand 
Central  Palace  during  Exposition  Week, 
probably  London,  Paris  and  Berlin  wilt 
be  "plugged  in,"  through  high  power 
transmission,  and  the  first  exchange  of 
international  concerts,  it  is  expected,  will 
take  place  on  the  opening  night.  Dis- 
patches from  Berlin,  reflecting  the  great 
public  interest  created  in  Germany  by 
the  announcement  that  an  agreement  had 
been  concluded  between  wireless  interests 
in  that  country  and  America  for  an 
exchange  of  radio  concerts,  are  confirmed 
by  exhibitors  at  the  Fourth  Annual 
National  Radio  Exposition.  Technical 
experiments,  it  is  added,  will  begin  almost 
immediately,  and  by  September  the  regular 
exchange  of  concerts  should  be  in  force. 

The  present  outlook  is  that  the  Amer- 
ican radio  fan  will  be  greeted  at  the  Expo- 
sition in  at  least  four  different  languages 
from  as  many  parts  of  the  world.  On  the 
other  hand,  the  messages  delivered 
through  the  microphone  in  Grand  Cen- 
tral Palace  by  leading  figures  in  American 
public  and  industrial  life,  will  be  heard  in 
millions  of  homes  across  the  Atlantic. 

Radio  interests  representing  an  annual 
business  of  over  5300,000,000  will  exhibit 
at  the  Fourth  Annual  National  Radio 
Exhibition.  So  complete  and  elaborate 
are  the  exhibits  to  be  offered  this  year  to 
the  radio  trade  and  the  radio  public  that 
the  third  floor  of  the  Grand  Central 
Palace  has  had  to  be  opened  for  the 
Exposition,  in  addition  to  the  ground 
and  mezzanine  floors.  Nor  is  public 
interest  less  keen.  Reservations  already 
had  been  received  for  over  50,000  tickets 
from  large  industrial  organizations, 
national  institutions  and  dealers  through- 
out the  country. 

An  Antenna  Support  for 
City  Dwellers 

An  attractive  antenna  support  for  the 
use  of  cliff  dwellers  in  the  city  who  desire 
that  radio  shall  be  as  unobtrusive  as. 
possible,  has  been  designed  and  marketed 
by  the  Jife  Support  Co.,  at  5568  West 
Van  Buren  St.,  Chicago,  111. 

The  device  consists  of  a  wire  spring 
clamp  which  encircles  a  small  porcelain 
insulator.  The  clamp  is  slipped  onto 
picture  moulding;  the  wire  which  is  to 
be  strung  up  inside  the  house  is  passed 
through  the  insulator  held  by  the  spring 
and  the  job  is  complete. 


/TLabor* 


Dis/or/ion/ess  rfmptiflcation. 

12,000.    48.000.    50.000.     100.000  Ohms.     List 

S1.50  each.     Special  sizes   to  Order  -S2.50  each. 

^Dealers,  write  for  discounts.      When  Better  Resistances 

are  made  then  will  be  Crescents. 

Crescent  Radio  Supply  Co.,  5  Liberty  St.,  Jamaica,  N.Y 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


91 


James  F.  Kerr,  Noted 
Showman,  Dies 

It  is  with  profound  regret  that  we 
announce  to  the  radio  industry  the 
untimely  death  of  James  F.  Kerr,  general 
manager  of  the  Radio  World's  Fair  and 
nationally   known   showman. 

Mr.  Kerr's  sudden  demise  will  in  no 
way  alter  the  policy  and  activities  of  the 
Second  Radio  World's  Fair  and  the 
Fourth  Annual  Chicago  Radio  Show,  it 
has  been  announced.  U.  J.  Herrmann, 
Managing  Director  of  both  shows,  and 
closely  identified  in  their  management, 
welfare  and  success  in  the  past,  will 
continue  to  carry  them  on  with  the  same 
degree  of  perfection  as  attained  at  previ- 
ous shows. 

Mr.  Herrmann  was  to  have  sailed  with 
the  Donald  B.  McMillan  Expedition  from 
Boston  on  June  17th,  but  has  now  cut 
short  his  trip  in  order  to  devote  his 
undivided  attention  to  the  direction  of 
the  forthcoming  Second  Radio  World's 
Fair  and  the  Fourth  Annual  Chicago 
Radio  Show. 

Brandes  Broadens  Line 

Since  1908  Brandes  have  been  special- 
izing in  radio  acoustics  and  their  labora- 
tories have  been  constantly  striving  to 
improve  the  audio  circuit  of  the  radio 
receiving  set  because  it,  in  the  final 
analysis,  determines  the  quality  of  the 
reception.  This  work  has  resulted  in 
the  following  new  additions  to  their  line: 

A  new  audio  transformer  which  ampli- 
fies without  distortion  frequencies  from 
200  to  4000  cycles  per  second  with  the 
high  voltage  amplification  ratio  of  1  to  5. 
It  is  so  designed  that  two  stages  of  ampli- 
fication may  be  employed  without  sac- 
rificing quality  of  reproduction.  It  is 
provided  with  outside  soldering  terminal 
connections,  screw  mounting  base,  and 
is  completely  shielded. 

Announced  also  is  a  new  horn  speaker 
(Type  H),  which  is  somewhat  larger  than 
their  Table-Talker  and  gives  much 
greater  volume.  This  speaker  has  lam- 
inated pole  pieces  which  increase  its 
magnetic  efficiency,  and,  in  turn,  increase 
its  volume. 


"THE  TUBE  WITH  A  PEDIGREE" 


V^HERE  is  only  one  way  to  measure  the 
value  of  a  radio  tube,  regardless  of  who 
made  it,  and  that  is  by  the  characteristic 
curve  reading.  In  this  way,  and  no  other, 
can  its  value  as  a  tube  be  determined  in 
advance.  All  MUSSELMAN  TUBES 
have  a  characteristic  curve  slip  inclosed 
at  the  factory  and  certified  when  the  read- 
ings are  above  the  standard  set  by  leading 
radio  engineers  as  to  what  constitutes  an 
unusually  good  tube. 

Jobbers,  manufacturers,  and 

dealers  are  Invited  to  write  for 

details  as  to  sales  franchise. 

Manufactured  by 

The  Van  Home  Co.,  Franklin,  Ohio 

SALES  OFFICE 

A.  J.  MUSSELMAN 

601-C  Machinery  Hall      -      CHICAGO 


French  Battery  Reorganized 

A  refinancing  plan,  whereby  the  French 
Battery  Company  at  Madison,  Wiscon- 
sin, will  be  able  to  greatly  increase  the 
output  ol  that  plant,  has  been  announced 
by  officials  of  the  company.  At  a  stock- 
holders' meeting  recently,  it  was  decided 
to  increase  the  preferred  stock. 

The  reorganization  plan  which  makes 
the  Madison  concern  one  of  the  largest 
manufacturers  of  dry  batteries  and 
flashlights  in  the  United  States  does  not 
involve  any  changes  in  personnel. 

In  view  of  the  fact  that  the  company  has 
decided  to  intensify  on  the  production 
of  dry  batteries  and  flashlights,  the 
directors  voted  to  drop  the  word  "Car- 
bon" from  the  name  of  the  company, 
giving  the  firm  the  new  title  of  "The 
French  Battery  Company." 

"Arctic"  to  Pierce  North  for  Canada 

New  Arctic  radio  transmission  records 
undoubtedly  will  be  established  when 
the  Canadian  Government  ship  "Arctic" 
enters  the  polar  regions  on  her  annual 
trip  this  Summer.  The  vessel  will  be 
equipped  with  a  transmitting  set  espec- 
ially designed  to  keep  the  Canadian 
Government  posted  on  her  movements  in 
the  land  of  the  midnight  sun.  The 
Arctic  will  leave  Quebec  about  June  27. 

The  vessel  holds  the  present  record  for 
receiving  and  transmitting  radio  messages 
from  the  point  nearest  the  North  Pole. 
The  Canadian  Government  is  preparing 
to  start  the  ship  off  on  her  voyage  some- 
what earlier  this  year,  in  order  to  pierce 
fart  her  in  to  the  Arctic  ice  field  than  it  did  in 
1924.  The  staunch  ship,  built  especially 
for  Arctic  travel,  is  being  reinforced  on 
bow  and  stern  with  heavy  steel  plates  to 
fight  its  way  through  the  ice  to  a  point 
farther  north  than  it  has  been  able  to 
penetrate  most  of  the  20  years  it  has  been 
making  annual  pilgrimages  to  the  Arctic 
circle. 

Last  year  the  vessel  continuously 
received  messages  from  the  Canadian 
government  transmitted  from  Station 
KDKA,  on  the  short  wave,  and  estab- 
lished the  "farthest  north"  reception 
record  when  a  message  from  KDKA 
was  received  at  Cape  Sabine,  north  of 
Peary's  winter  base  at  Etah,  and  within 
11  degrees  of  the  north  pole. 

Not  all  the  reply  messages  sent  from 
the  vessel  to  the  Canadian  government 
were  received,  however,  and  in  order  to 
insure  uninterrupted  two  way  transmis- 
sion this  year,  Commander  C.  P.  Edwards, 
director  of  radio  service  of  the  Canadian 
Department  of  Marine  and  fisheries,  in 
collaboration  with  C.  W.  Horn,  superin- 
tendent of  radio  operations  of  the  West- 
inghouse  Company  and  the  KDKA 
engineers,  is  having  a  more  powerful  set 
built  for  the  vessel  this  vear. 


William  L.  Say  re  Joins 
H.  H.  Eby  Co. 

The  H.  H.  Eby  Manufacturing  Com- 
pany of  Philadelphia,  well  known  makers 
ol  quality  binding  posts,  recently  acquired 
the  services  of  William  L.  Sayre,  who  has 
been  identified  with  radio  interests  for 
the  past  fifteen  years. 

Mr.  Sayre  was  made  an  associate  of 
the  Institute  of  Radio  Engineers  in  1914 
and  later  of  the  American  Institute  of 
Electrical  Engineers.  His  earlier  training 
under  able  physicists,  coupled  with  his 
later  practical  radio  and  merchandising 
experience,  will  enable  the  Eby  organiza- 
tion to  offer  further  aid  to  its  many 
manufacturing  and  distributing  customers 
upon  whom  Mr.  Sayre  will  call  after  a 
time  spent  at  the  factory. 

*     Tested  and  Ajyproved  by  RADIO   AGE     ¥ 


Entirely  silver-plated!  And 
a  new  standard  has  been  set 
for  low-loss  condensers!  It 
is  only  logical  that  the  new 
Silver-Marshall  S-L-W  Con- 
densers should  be  the  first 
to  be  so  built.  Their  losses 
are  lower  than  many  labora- 
tory standards — their  me- 
chanical design  unique  and 
original.  The  S-L-W  plates 
mean  real  selectivity  and 
station  separation. 

No.  305      .0005 $6.00 

No.  306      .00035 5.75 

No.  307     .00025 5.50 


"I 


S-M  210  and  211  trans- 
formers are  known  as  the 
finest  intermediate  trans- 
formers ever  made.  They 
were  an  important  feature  of 
the  receiver  built  entirely  of 
S-M  parts,  that  took  the 
grand  sweepstake  prize  at 
the  recent  Los  Angeles  Radio 
Show.  Price,   each $8.00 

Send  4c  in  stamps  for  Free 
Circulars  of  S-M  Products,  and 
reprints  of  article  from  Radio 
Broadcast,  describing  the  remark- 
able new  Super-Autodyne  Re- 
ceiver. 

114  S.    Wabash   Ave. 
Chicago,   Illinois 


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Tone  loud  and  pleasing. 
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AMERICAN   ELECTRIC  COMPANY 

State  and  64th  Stg.,  Chicago 


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Are  you  ready  for  the  big  season  that 
starts  in  the  Fall?  Order  your  September 
RADIO  AGE  NOW! 


92 


RADIO  AGE  for  August,  1925 


The  Jewell 
Radio  Test  Set 

1  This  is  the  most  com- 
plete Radio  Test  Set  on 
the  market. 

1  Manufacturers,  Ex- 
perimenters, Jobbers  and 
Dealers  all  over  the  world 
are  using  it.  This  set  is 
Jewell's  outstanding  con- 
tribution to  Radio. 

Price  $752£ 

Send  for  Complete 
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WANT  SELECTIVITY? 

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&      Clearness  and  Volume? 

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Fills  the  Bill 

Jobbers  and  Dealers  Write  for  Exclusive  Appointments 

W-K  ELECTRIC  CO. 

KENOSHA,  WISCONSIN 


The  Magazine  of  the  Hour 

Brainard  Foote  Analyzes 
Tuning  Tricks 

(Continued  from  -page  10) 

tributed  capacity.  Then,  to  bring  KSD 
near  to  95  on  the  dial,  it  was  necessary 
to  remove  five  of  the  rotor  plates.  The 
condenser  is  then  really  only  a  15  plate 
instrument,  because  the  fixed  plates 
corresponding  to  the  removed  rotor 
plates  are  "dead"  too.  Thus  the  capacity 
is  reduced  to  about  7-12  of  its  former 
value,  or  about  .0003  mfds.  Two  marked 
improvements  result  from  this: 

1.  The  inductance  to  capacity  ratio 
is  much  higher  than  it  was,  meaning 
louder    signals. 

2.  The  tuning  scale  is  evenly  distributed 
over  the  entire  scale,  meaning  just  as 
good  selectivity  with  much  easier  tuning. 

Thus  one  of  the  chief  gains  made  by 
using  a  coil  having  low  distributed  ca- 
pacity, even  with  the  basket-wound 
type,  is  the  greater  wavelength  range 
possible  with  a  given  variable  condenser. 
It  must  be  understood  that  more  wire 
is  needed,  and  because  of  the  fact  that 
added  wire  means  added  resistance, 
some  might  think  the  spaced  system  a 
disadvantage.  However,  the  use  of  a 
higher  inductance  -  to  -  capacity  -  ratio 
throughout  the  scale  more  than  offsets 
the  slight   increase  in   wire  resistance. 

A  set  adjusted  to  tune  in  this  fashion, 
especially  if  the  condenser  be  one  of 
straight-line  wavelength,  as  in  Fig.  2, 
where  each  degree  represents  a  certain 
number  of  meters  (usually  3%  to  4J^ 
meters)  is  a  pleasure  to  operate.  To 
keep  it  smooth-running,  the  antenna 
absorption  must  not  interfere  on  short 
waves,  on  account  of  the  natural  period 
of   the   antenna   system. 

Antenna  Natural 

TN  THE  case  of  a  long  and  high  aerial, 
*■  the  natural  wavelength  may  lie  near 
200  meters  or  above  it,  including  the 
antenna  coupling  coil  of  the  set.  Hence, 
the  coupling  coil  should  have  a  tap  on  it, 
so  that  only  4  or  5  turns  are  used  for 
short  wave  coupling.  The  antenna 
natural  interferes  with  regeneration  and 
the  set  usually  will  not  oscillate  over 
4  or  5  degrees  near  its  lower  scale  in  case 
the  antenna  natural  is  too  high.  When 
the  natural  can't  be  reduced  by  using 
fewer  turns  in  the  coupling  coil,  a  small 
series  condenser  is  advised,  .00025  to 
.0005     mfds.    capacity. 

The  circuit  given  in  Fig.  3  shows  how 
the  regular  three-circuit  tuner  outfit 
can  be  rearranged  along  the  lines  of  this 
article.  In  addition,  the  method  of  re- 
generation does  not  interfere  with  the 
tuning  to  any  noticeable  extent,  the  two 
controls  being  independent  of  each  other. 
The  secondary  is  the  space-wound  coil 
about  4  inches  in  diameter  and  having 
about  60  turns,  or  any  number  necessary 
to  place  the  shortest  wavelength  at  200 
meters.  The  wire  ought  to  be  about 
No.  18  in  size,  although  no  smaller  than 
No.  22.  The  tickler  is  a  coil  having 
about  15  turns  wound  on  a  3-inch  tubing 
and  placed  inside  the  secondary  at  the 
filament  end.  The  primary  is  about 
ten  turns,  wound  on  the  same  tubing 
as  the  secondary  and  at  the  filament  end. 


*     Tested  and  Approved  by  RADK)  AGE     ¥ 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


The  tickler,  while'fixed  in  position,  must 
be  tried  reversed  in  case  its  direction 
is  wrong  for  oscillation.  If  wound  in 
the  same  direction  as  the  secondary, 
the  end  away  from  the  grid  goes  to  the 
regeneration    condenser. 

The  headphones  or  primary  of  the 
audio  transformer  act  as  a  radio  fre- 
quency choke  coil,  so  that  the  R.  F.  choke 
coil  often  specified  at  point  X  isn't 
needed  for  broadcast  waves.  Care  must 
be  taken  not  to  use  a  fixed  condenser 
across  the  phones  or  transformer  pri- 
mary, however.  There  should  be  no 
more  turns  than  necessary  on  the  tickler 
to  secure  regeneration,  for  with  too  many 
turns  the  range  of  the  regeneration  con- 
denser will  be  constricted  and  it  will  be 
hard  to  adjust  the  tube  to  the  "edge" 
of  oscillation,  just  as  it  is  when  the 
usual  type  of  tickler  is  too  big.  If  the 
tube  oscillates  with  only  10  turns  on  it. 
so  much  the  better. 


s^gesagsg 


Deciding  on  a  Portable 
Super-Het 

(Continued  from  page  14) 

will  be  proportionately,  due  to  the 
elimination  of  reaction,  etc.,  which  is 
bound  to  occur  to  a  varying  extent  in 
every  amplifier.  With  the  transformers 
used  in  the  portable  super,  two  stages 
will  get  down  to  the  noise  level  under 
average  conditions.  The  question  then 
arises  as  to  why  we  whould  use  three 
stages  when  we  obtain  the  same  results 
with  two,  and  save  a  tube  and  batteries. 
The  average  fan's  answer  is  "greater 
sensitivity"  but  he  forgets  entirely  the 
noise  level  and  the  fact  that  more  than  a 
given  value  of  sensitivity,  assuming  for  a 
moment  that  it  would  result  from  the  use 
of  a  third  stage,  is  worse  than  useless. 

There  is  no  question  but  that  a  novice 
can  assembly  a  two-stage  audio  amplifier 
and  make  it  work  perfectly.  Yet  the 
same  man  will  have  great  difficulty 
assembling  a  comparatively  high  fre- 
quency RF  amplifier.  The  same  condi- 
tions hold  in  an  intermediate  amplifier 
and  the  number  of  successful  supers 
that  have  been  built  using  iron-core 
transformers  indicate  they  are  far  the 
easiest  to  build  in  actual  practice.  Where 
only  two  stages  are  used,  the  efficiency 
per  stage  is  increased  over  a  three-stage 
amplifier,  the  possibility  of  trouble  in  the 
amplifier  decreases  25  per  cent;  and  a 
tube,  its  socket,  a  transformer  and  some 
wiring  are  eliminated.  This  is  a  decided 
advantage. 

From  the  foregoing  it  is  evident  that 
on  the  counts  of  amplification  and  current 
consumption,  the  iron-core  transformer 
is  far  superior  to  the  air-core  system, 
even  when  the  latter  is  built  in  the  form 
of  a  tuned  neutrodyned  system.  From 
the  novice  standpoint,  the  additional 
stability  and  ease  of  assembly  put  the 
iron-core  system  far  ahead  of  the  high 
frequency  amplifier. 

It  will  be  seen,  then,  that  the  choice  of 
transformers  is  important,  affecting  as 
it  does  the  operation  of  the  entire  super. 
Transformers  that  are  tested  and  match- 
ed as  to  curves  and  peaks,  in  careful 
laboratory  tests,  are  the  best  for  portable 
supers,  for  they  eliminate  all  possibility 


JEFFERSON 

TRANSFORMERS 


TwoPopularTypes  of 
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Living  tones  of  music  and  song,  drawn  into  the  "mikes"  for  your 

entertainment,  get  the  reproduction  they  deserve  with  Jefferson 

Radio   Transformers  as  part  of  your  set.      The  extraordinarily 

accurate  amplification  afforded  by  Jefferson  Transformers  brings 

in  to  you  the  music  from  the  air  as  you  would  hear  it  in  the  studio.        » 

Jefferson  Transformers  give  their  best,  just  as  the  artist  does.  vtf 

It  takes  pains — and  brains — to  make  fine  transformers.   Our  recipe 

for  leadership  in  the  field  is  simple:      We  devote  all  our  time 

and  manufacturing  experience  to  transformers  and  coils. 

A  good  set  demands  Jefferson  Transformers  to  make  it  better. 

Good  dealers  sell  them. 

JEFFERSON  ELECTRIC  MFG.  CO. 


501  S.  Green  Street 


Chicago,  Illinois 


Makers  of  Radio  Tube  Rejuvenators,  Radio  Transformers, 
Bell-Ringing  Transformers,  Sign-Lighting  Transformers. 
Automobile  Ignition  Coils,  Jump  Spark  — •  Make  and  Break 
Coils,  Auto  Transformers,  Testing  Instruments,  Toy 
Transformers,  Furnace  and  Oil  Burner  Transformers,  Oil 
Burner  Ignition  Coils. 


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94 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


CONDI 


■r^C 


v 


"1FLEX 

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Chicago 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


95 


Causes  of  Variation  in 
DX  Results 

(Continued  from  page  16) 

causing  a  maximum  disturbance  at  that 
time. 

Lightning  discharges  also  cause  a  great 
amount  of  noise  in  a  receiving  set,  espe- 
cially during  the  summer,  when  electric 
storms  are  frequent  and  most  severe. 
It  is  surprising  to  many  when  they  learn 
that  these  disturbances  are  not  usually 
heard  over  distances  greater  than  100 
miles.  These  disturbances  cause  sharp 
clicks  of  considerable  intensity  in  the 
receiver. 

Another  condition  which  is  often  found 
to  be  very  annoying  is  fading.  Many 
theories  have  been  advanced  regarding 
the  causes  of  fading,  but  the  latest  infor- 
mation upon  the  subject  seems  to  indi- 
cate that  it  is  largely  a  matter  of  inter- 
ference between  direct  waves  and  waves 
that  .have  been  reflected  from  the  Heavi- 
side  layer,  which  is  a  layer  of  ionised 
air  in  the  upper  strata  of  the  earth's 
atmosphere.  This  ionised  air  has  the 
peculiar  property  of  reflecting  radio 
waves  in  a  manner  which  might  be  com- 
pared to  a  mirror  reflecting  a  beam  of 
light. 

Sketch  3  illustrates  how  both  the  direct 
and  reflected  waves  travel  from  the  trans- 
mitter to  the  receiver.  It  is  evident 
that  the  reflected  wave  travels  much 
farther  than  the  direct  wave  and  is  there- 
fore subject  to  being  out  of  phase  with 
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Heaviside  layer  varies,  the  phase  rela- 
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extent  to  which  the  two  waves  aid  or 
oppose  each  other.  It  is  possible  for 
the  two  waves  to  entirely  neutralize 
each  other,  causing  the  signal  to  disappear 
entirely,  or  they  may  aid  each  other  and 
cause  an  abnormally  loud  signal  in  the 
receiver.  Exhaustive  tests  have  proven 
that  barometric  pressures  also  affect 
signal  intensity  and  sometimes  cause 
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*     Tested  and  Approved  by  KADIO  AGE     * 


96 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


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Solving  the  Question  of 
I.  F.  Transformers 

(Continued  from  page  89) 

It  is  commonly  accepted  that  a  wave- 
length in  the  neighborhood  of  five  to 
seven  thousand  meters  is  most  satis- 
factory, preference  being  given  to  5,000 
meters,  since  transformers  may  be  made 
more  selective  at  this  wave  than  at  the 
longer  ones.  Obviously,  a  transformer 
wound  with  a  large  low-loss  air-core 
coils,  tuned  by  a  low-loss  condenser, 
would  give  maximum  gain.  Actually,  it 
would  be  so  sharp  as  to  cut  side-bands, 
and  would  have  a  terrific  field,  resulting 
in  instability  and  inability  to  use  more 
than  one  or  two  such  coils.  The  next 
step  is  an  air  core  transformer  with 
smaller  coils  of  higher  resistance.  How- 
ever, the  same  troubles  prevail  in  a 
lesser  degree  until  we  resort  to  an  iron 
core,  which  limits  the  transformer  field, 
broadens  the  curve  to  the  desired  width, 
and  reduces  amplification.  If  we  go 
further,  and  use  a  large  iron  core,  we  get 
a  nice  flat  curve,  wonderful  reproduction, 
no  selectivity,  and  no  gain.  It  is  obvious 
again  that  we  must  resort  to  a  compromise, 
and  if  this  paper  has  brought  out  this  single 
point,  the  writer  feels  amply  repaid, 
for  it  may  be  said  that  the  necessity  for 
compromise  between  desirable  theoreti- 
cal extremes  is  an  axiom  of  radio  equip- 
ment engineers. 

Looking  at  the  curves  of  Figure  1,  we 
see  A,  B,  C  and  D.  "A"  represents 
the  ideal  transformer,  giving  infinite 
amplification  over  a  10,000  cycle  band, 
yet  at  no  other  frequencies.  "B"  is  an 
air-core  transformer  giving  the  highest 
possible  amplification.  It  is  useless,  since 
it  will  not  pass  music  and  speech,  and  is 
subject  to  the  physical  limitations  pre- 
viously set  forth.  "C"  is  the  practical 
ideal  transformer,  passing  the  desired 
frequency  band  with  a  gain  variation 
insufficient  to  cause  distortion,  yet  with  a 
limited  field  and  good  stability.  "D"  is 
the  extreme  for  perfect  reproduction — 
but  gives  no  selectivity  and  no  amplifica- 
tion to  speak  of. 

Construction  Details 

SUPPOSE  we  wish  to  construct  "C", 
which  is  the  best  transformer  we 
can  build  practically.  We  will  require  a 
bobbin  turned  out  of  wood  or  built  up 
of  fibre,  together  with  two  pieces  of  core 
iron  as  shown  in  Figure  2.  This  bobbin 
is  wound  with  1,400  turns  of  No.  36  SSE 
in  the  smaller  slot  for  the  primary,  and 
3300  turns  of  the  same  wire  in  the  larger 
slot  for  the  secondary.  The  core  is  put 
in  so  that  the  air-gap  comes  under  the 
larger  or  secondary  coil,  and  the  ends  of 
the  laminations  are  bent  over  each  other 
to  hold  them  together.  This  transformer 
may  be  placed  in  a  small  metal  can, 
with  leads  brought  out  as  desired.  It 
should  first  be  boiled  in  a  resin-bees-wax 
compound,  with  which  the  can  should  be 
filled. 

This  transformer,  while  selective,  may 
best  be  used  in  conjunction  with  another 
type,    which    would    be    a    compromise 
between  "B"  and  "C". 
*     Tested  and  Approved  by  RADIO  AGE     * 


Apr. 


Qeared  80  to  1 


Adaptable  to  coarse  or 
fine  tuning,  the  infinite 
precision  ofthe  Accura* 
tune  brings  in  all  sta- 
tions within  the  scope 
of  your  set  clearly, 
strongly,  and  with  little 
effort  on  your  part. 
Easily  substituted  in  a 
few  minutes  for  ordi- 
nary dials  without  al- 
teration of  your  set.  An 
essential  accessory. 
Write  for  descriptive  folder 
MYDAR  RADIO  CO. 

17  CAMPBELL  STREET 
.     -  NEWARK,  N.  J. 

^TAccURATUNE 


4Hg 


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SALESPEAKER 

is  the  name  of  the  most  interesting 
radio  bulletin  published.  If  you  are  a 
dealer,  we  will  mail  you  a  copy,  on 
request. 
^HUDSON-ROSS— 116  S.  Wells  St. 
Chicago 


RADIO  AGE  for  August,  1925 


This  latter  transformer  may  be  built 
by  turning  out  a  wood  spool.  In  the 
bottom  of  the  slot  are  wound  250  turns 
of  No.  30  DSC  wire.  On  top  are  wound 
1,500  turns  of  No.  36  DSC  wire,  forming 
the  secondary.  This  coil  has  an  air  core, 
and  cuts  side  bands  slightly.  Using  but 
one,  this  is  not  noticeable,  but  the  use  of 
two  or  three  would  be  out  of  the  question 
for  reasons  outlined  above,  in  addition 
to  this  latter  one. 

Now  that  we  have  these  transformers, 
we  cannot  use  them  unless  they  are 
properly  matched.  Such  a  step  will 
insure  co-ordinate  operation  at  all  times. 


The  Magazine  of  the  Hour 


97 


/crisscross  I 

I       fVTHE  COUNTRY  WITH         J 


.5  TUBE 


Something  decidedly  new,   different,  and 
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Send  me  immediately  full  information  about  the  new  Prei 
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RADIO  AGE  FOR  ONE  YEAR  AND  1925  RADIO 
AGE  ANNUAL— BOTH  FOR  $2.50! 

Here  is  a  bargain!  For  a  limited  period  only,  we  are  offering  RADIO 
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amazing  value.     Fill  out  below  and  send  it  in: 

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Enclosed  is  $2.50,  (stamps,  money  order  or  cash,)  for  which  send  me 
RADIO  AGE  for  one  year  beginning  with  the  current  issue,  and  the 
ANNUAL  for  1925. 

Name 

Address — 

City  and  State._ : 


WANTED— CHICAGO  REPRESENTATIVE 

Manufacturer  engaged  in  the  making  of  kit,  radio  set  and 
loud  speaker  desires  Chicago  distributor  with  financial  and 
merchandising  responsibility  to  handle  exclusive  representation 
in  Chicago.  Dealers  to  be  given  exclusive  territory.  Price 
and  quality  will  be  maintained.  This  is  a  desirable  connection 
for  the  right  party. 

Address — -Box  H-8, 

Radi»  Age, 

500  N.  Dearborn  St.,  Chicago,  111. 


*     Tested  and  Approved  by  RADIO   AGE     * 


98 


KDKA 

KDLR 

KDPM 

KDYL 

KDZB 

KDZI 

KFAD 

KFAE 

KFAF 

KFAJ 

KFAN 

KFAU 

KFAW 

KFBB 

KFBC 

KFBG 

KFBK 

KFBL 

KFCB 

KFCF 

KFCZ 

KFDD 

KFDH 

KFDJ 

KFDM 

KFDX 

KFDY 

KFDZ 

KFEC 

KFEK 

KFEL 

KFEQ 

KFER 

KFEY 

KFFP 

KFFV 

KFGB 

KFGC 

KFGD 

KFGH 

KFGQ 

KFHA 

KFHH 

KFHL 

KFI 

KFIF 

KFIO 

KFIQ 

KFIU 

KFIX 

KFIZ 

KFJB 

KFJC 

KFJF 

KFJI 

KFJL 

KFJM 

KFJR 

KFJX 

KFJY 

KFJZ 

KFKA 

KFKQ 

KFKU 

KFKX 

KFLD 

KFLP 

KFLR 

KFLU 

KFLV 

KFLX 

KFLZ 

KFMB 

KFMQ 

KFMR 

KFMT 

KFMW 

KFMX 

KFNF 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


Waiting houoe  Electric  A  Mfg.  Co East  Pittsburgh.  Pa. 

Radio  Electrio  Co Devila  Lake,  N.  D. 

Wsi  tinghome  Electric  A  Mfg.   Co Cleveland,   Ohio 

Newhouse    Hotel Salt    Lake    City,    Utah 

Frank    E.    Siefert Bakersfield.    Calif. 

Electrio  Supply  Co Wenatchee,  WaBh. 

MoArthur   Bros.   Mercantile  Co Phoenii,   Arix. 

State  College  of  Washington Pullman,  Wash. 

Western    Radio   Corporation Denver.   Colo. 

University  of  Colorado- Boulder,   Colo. 

University  of   Idaho Moscow,   Idaho 

Boise  High   School . Boise,   Idaho 

The  Radio  Den  (W.  B.  Ashford) Santa  Ana,  Calif. 

F.  A.  Buttrey  A  Co Havre,  Mont. 

W.   K.  Aibill San  Diego.   Calif. 

First   Presbyterian   Church Tacoma,   Wash. 

Kimball-Upson     Co Sacramento.  Calif. 

Leese  Bros Everett,  Wash. 

Nielson    Radio  Supply   Co Phoenix,   Aril. 

Frank  A.  Moore Walla  Walla,  Wash. 

Omaha   Central   High   School Omaha,   Nebr. 

St.     Michaels     Cathedral Boise,     Idaho 

University  of  Arizona Tuacon,   Arii. 

Oregon    Agricultural    College Corvallia.    Oreg. 

Magnolia  Petroleum  Co Beaumont,  Texas 

First   Baptist  Church Sbreveport.    La. 

South    Dakota  State   College Brookings,   8.   Dak. 

Harry    O.    Iverson Minneapolis,    Minn. 

Meier  A  Frank  Co Portland,  Oreg. 

Augsbury    Seminary Minneapolis,    Minn. 

Winner    Radio    Corp Denver,    Colo. 

J.  L.  Seroggin    Oak,  Nebr. 

Auto   Electric  Service   Co Fort  Dodge.   Iowa 

Bunker  Hill  A  Sullivan  Mining  and  Concentrating  Co Kellogg,  Idaho 

First    Baptist    Church Moberly,    Mo. 

Oraceland    College Lamoni,  Iowa 

Heidbreder   Radio  Supply   Co Utica.   Neb. 

Louisiana    State    University Baton    Rouge.    La. 

Chickasha  Radio  A  Electric  Co Chickasha,  Okla. 

Leland  Stanford  University Stanford  University,  Calif. 

Crary    Hardware    Co Boone,     Iowa 

Western  State  College  of  Colorado Gunnison,   Colo. 

Ambrose  A.  McCue Neah  Bay.  Wash. 

Penn     College OaValoosa.   Iowa 

E.  C.  Anthony,  Inc Los  Angeles,  Calif. 

Benson   Polytechnic  Institute Portland,  Oreg. 

North    Central    High    School Spokane,    Wash . 

First   Methodist   Church Yakima.   Wash. 

Alaska  Electrio  Light  A  Power  Co ,  Juneau,  Alaska 

Reorganised  Church  of  Jesus  Christ  of  Latter  Day  Saints.  Independence,  Mo. 

Dally  Commonwealth  and  Oscar  A.  Huelsman Fond  du  Lac,  Wis. 

Marshall    Electrical    Co Marshalltown.    Iowa 

R.  B.  Fegan  (Episcopal  Church) Junction  City,  Kansas 

National   Radio  Manufacturing  Co Oklahoma  City,  Okla. 

Liberty  Theatre  (E.  E.  Mar«h) Astoria,  Oreg. 

Hardsaog    Manufacturing    Co Ottumwa,    Iowa 

University  of  North  Dakota Grand  Forks.  N.  Dak. 

Ashley  C.   Dixon   A   Son StevenBville.  Mont. 

Iowa  State  Teacher's  College Cedar  Falls,  Iowa 

Tunwall  Radio  Co Fort  Dodge,  Iowa 

W.  E.  Branch Fort  Worth,  Texas 

Colorado  State  Teachers  College  Greeley,  Colo. 

Conway  Radio  Laboratories   (Ben   H.  Woodruff) Conway.  Ark. 

The  University  of  Kansas Lawrence,  Kans. 

Westinghouse  Electric  A  Manufacturing  Co Hastings,  Nebr. 

Paul    E.    Greenlaw Franklinton.  La. 

Everett   M.    Foster Cedar    Rapids,    la. 

University   of    New    Mexico Albuquerque,  New  Mexico 

Rio  Grande  Radio  Supply  House San  Benito,  Texas 

Rev.   A.   T.    Frykman Rockford.    111. 

George    Roy  Clough Galveston.  Texas 

Atlantic   Automobile   Co.    Atlantic.    la. 

Christian    Churches Little    Rock.    Ark. 

University  of  Akransas Fayetteville.  Ark. 

Morningside  College. Sioux  City,   Iowa 

Dr.    George    W.    Young Minneapolis,    Minn. 

M.  G.  Sateren Houghton.  Mich. 

Carleton  College Northfield,  Minn. 

Henry  Field  Seed  Co Shenandoah.  U 


KFNG  TWooten's  Radio  Shop Coldwater,  Miss. 

KFNV        L.  A.  Drake  Battery  and  Radio  Supply  Shop Santa  Rosa.  Calif. 

KFOA        Rhodes     Department    Store Seattle,  Wash. 

KFOC        First    Christian    Church Whittier,    Calif. 

KFOJ         Moberly  High  School  Radio  Club Moberly.  Missouri 

KFOL        Leslie  M.  Schafbush Marengo.  Iowa 

KFON       Echophone    Radio   Shop Long  Beach,  Calif. 

KFOO        Latter  Day  Saints  University Salt  Lake  City,  Utah 

KFOP        Rohrer  Elec.   Co Marshfield,  Ore. 

K  FOR        David  City  Tire  A  Electric  Co David  City.  Nebraska 

KFOT        College  Hill  Radio  Club Wichita.  Kansas 

KFOX       Board  of  Education.  Technical  High  School Omaha,  Nebraska 

KFOY       Beacon  Radio  Service St.  Paul.  Minn. 

KFPG       Garretson  and  Dennis Los  Angeles,  Calif. 

KFPL        C.    C.    Baxter Dublin,  Texas 

•CFPM       The  New  Furniture  Co Greenville.  Texas 

KFPR        T.os  Angeles  Co.  Forestry  Dept Los  Angeles.  Calif. 

KFPT       CaD*  A  Johnson Salt  Lake  City.  Utah 

KFPV         Heinta  A  Kohlmoos.   Inc San  Francisco.   Calif. 

ICFPW       St.  Johns  M.  E.  Church Carterville.  Mo. 

KFPY        Rvroons  Investment  Co Spokane,  Wash. 

KFOA        The   Prineinia.  . St.  Louis,   Mo. 

KFQB        The  Searchlight  Publishing  Co Fort  Worth,  Texas 

KFOC        Kidd    Brothers    Radio   8hop Taft,    Calif. 

KFQH        Radio    Service    Co Burlingame,  Calif. 

KFOP        G.    S.    Carson.    Jr Iowa   City.    la. 

KFOR       Walter    LaFayette   Ellis Oklahoma    City.    Okla. 

K*"OT       T*xas  National  Guard Dennison.  Texas 

KPOU       W.  Riker Holy  City,  Calif. 

KFOW      C.  F.  Knierim North  Bend,  Wash. 

KFOY       Farmers    State    Bank Belden,  Neb. 

KFOZ        Taft     Radio     Co Hollwyood.  Calif. 

KFRC        City  of  Paris  Dry  Goods  Co San  Francisco.  Calif. 

KFRM       James   F.   Boland Fort   Sill.   Okla. 

KFRU        Etherical  Radio  Co Bristow,  Okla. 

KFRW       United  Churches  of  Olympia Olympia.  Wash. 

KFRX        J.  Gordon  Klemgard Pullman.  Wash. 

KFRZ        The  Electric  Shop Hartington.  Neb. 

KFSG        Angelus   Temple Los   Angeles,    Calif. 

KFSY        The   Van   Blaricon    Co Helena,    Mont. 

KFUJ         Hopper  Plumbing  and  Heating  Co Breckenridge,  Minn. 

KFUL        Thomas  Goggan  A  Bros.  Music  Co Galveston,  Texas 

KFUM       W.  D.  Corlev Colorado  Springs,  Colo. 

KFUO        Concordia     Seminary 8t.   Louis.  Mo. 

KFUP        Fitisimmons  General  Hospital Denver,  Colo. 

KFUQ       Julius  Brunton  and  Sons  Co San  Francisco.  Calif. 

KFUR        H.  W.  Peerv  and  C.  Redfield Ogden    Utah 

KFUS        Louis     L.     Sherman ,.. .Oakland,     Calif. 

KFUT        University    of    Utah Salt  Lake  City.  Utah 

KFUU        Colburn    Radio    Labs San    Leandro,    Calif. 

KFUY       Irvine    M.    Bouchard Butte.  Mont. 

KFUZ        Y.   M.    C.    A Virginia.    Minn. 

KFVC        Bensberg'n  Muslo  Co Camden.  Arkansas 

KFVf>        MoWhinnte  EUotrio  Co San  Pedro.  Calif. 

KFVE        Film   Corooration    of  America St    Louis    Mo 

K^VF        Clarence   B.   Juneau Hollywood.    Calif 

KFVG        First   M.   E.   Church , Independence.  Kansas 


309 

KFVH 

231 

KFVI 

270 

KFVJ 

2S0 

KFVK 

240 

KFVL 

360 

KFVN 

273 

KFVO 

348 

KFVR 

278 

KFVS 

360 

KFVY 

230 

KFVZ 

271 

KFWA 

280 

KFWB 

360 

KFWD 

278 

KFWH 

250 

KFWI 

283 

KGB 

224 

KGO 

238 

KGU 

256 

KGW 

258 

KGY 

252 

KHJ 

368 

KHQ 

254 

KJR 

3IS 

KJS 

360 

KLDS 

360 

KLS 

231 

KLX 

248 

KLZ 

261 

KMJ 

254 

KMO 

268 

KNX 

231 

KOA 

233 

KOB 

26 

KOP 

280 

KPO 

224 

KPPC 

254 

KPRC 

248 

KQV 

273 

KOW 

226 

KRE 

252 

KSAC 

261 

KSD 

240 

KSL 

468 

KTCL 

248 

KTHS 

252 

KTW 

242 

KUO 

226 

KUOM 

240 

KWG 

273 

KWK.C 

248 

KWWC 

219 

KYO 

252 

KYW 

252 

KZM 

242 

WAAB 

280 

WAAC 

258 

WAAD 

280 

WAAF 

246 

WAAM 

254 

WAAW 

273 

WABA 

250 

WABB 

273 

WABC 

288 

WABI 

234 

WABL 

256 

WABN 

254 

WABO 

236 

WABQ 

229 

WABR 

240 

WABU 

273 

WABW 

254 

WBAX 

299 

WABY 

261 

WABZ 

231 

WADC 

266 

WAFD 

336 

WAHG 

266 

WAMD 

254 

WBAA 

234 

WBAC 

454 

WBAH 

236 

WBAK 

246 

WBAO 

234 

WBAP 

234 

WBAV 

261 

WBAX 

240 

WBAY 

226 

WBBG 

231 

WBBL 

248 

WBBM 

226 

WBBN 

238 

WBBP 

242 

WBBR 

242 

WBBS 

231 

WBBU 

268 

WBBV 

236 

WBBX 

268 

WBBY 

283 

WBCN 

264 

WBDC 

221 

WBES 

258 

WBGA 

231 

WBOQ 

284 

WBR 

220 

WBRC 

252 

WBRE 

253 

WBS 

248 

WBT 

273 

WBZ 

240 

WCAD 

268 

WCAE 

263 

WCAG 

394 

WCAH 

220 

WCAJ 

217 

WCAL 

222 

WCAO 

272 

WCAP 

261 

WCAR 

242 

WCAS 

288 

WCAT 

242 

WCAU 

549 

WCAX 

234 

WCAZ 

234 

WCBA 

224 

WCBC 

233 

WCBD 

271 

WCBE 

231 

WCBF 

254 

WCBC 

244 

WCBH 

246 

WCBM 

202 

WCBN 

243 

WCBQ 

208 

WCBR 

236 

WCBT 

Whan  Radio  Shop   (Herbert  Whan) Manhattan,   Kansas  218 

Headquarters  Troop.  56th    Cavalry Houston.  Texas  248 

First  Baptist   Church San  Jobs  ,  Calif.  226 

Sacramento  Chamber  of  Commerce Sacrament".  Calif.  248 

Lt.  Richard  F.  Lussier,  5th  Inf.  U. S.  A.,  Vancouver  Barracke.Vanco  a  er.  Wash.  231 

Carl  E.  Bagley Welcome.  Minn.  227 

F.  M.  Henry Kirksville.  Mo.  226 

Moonlight  Ranch Route  6.  Denver,  Colo.  246 

Cape  Girardeau  Battery  Station Cape  Girardeau.  Mo.  224 

Radio  Supply  Co Albuquerque,  N.  M.  250 

Glad  Tidings  Tabernacle San  Francisco,  Calif.  234 

Browning   Bros.   Co Ogden,   Utah  214 

Warner  Bros Hollywood,   Calif.  252 

Arkansas  Light  A  Power  Co Arkadelphia,  Arkansas  266 

F.  Wellington  Morse,  Jr Chico,  Calif.  254 

Radio  Entertainments.  Inc South  San  Francisco.  Calif.  220 

Tacoma  Daily  Ledger Tacoma,  Wash.  252 

General  Electric  Co Oakland.  Calif.  361 

Marion    A.    Mulrony ...Honolulu,    Hawaii.   Waikiki    Beaoh  370 

Portland   Morning  Oregonian Portland,   Oreg.  491 

St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy,  Wash.  153 

Times-Mirror    Co Loa    Angeles,    Calif.  405 

Louis  Wasmer Seattle  ,Waeh.  273 

Northwest  Radio  Service  Co Seattle,  Wash.  384 

Bible  Institute  of  Los  Angeles.  Inc Los  Angeles.  Calif.  293 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints .  .  Independence,  Mo.  441 

Warner   Brothers   Radio   Supplies   Co Oakland,   Calif.  242 

Tribune    Publishing    Co Oakland.    Calif.  508 

Reynolds     Radio     Co Denver,  Colo.  263 

San  Joaquin   Light  A   Power  Corp Fresno,   Calif.  243 

Love    Electric    Co Tacoma.    Wash.  250 

Los  Angeles  Evening  Express Loa  Angeles,   Calif.  337 

General   Electric   Co Denver,  Colo.  323 

New  Mexico  College  of  Agriculture  A  Mechanic  Arts.  State  College,  N.  Mex.  34S 

Detroit    Police  Department Detroit.  Mich.  286 

Hale    Bros San  Francisco.  Calif.  428 

Pasadena  Presbyterian  Church Pasadena.    Calif .  229 

Houston    Post-Dispatch Houston,    Texas  270 

Doubleday-Hill     Electric     Co Pittsburgh,  Pa.  270 

Charles  D.    Herrold San  Jose,    Calif.  226 

V.   C.   Battery  A  Electric    Co Berkeley,  Calif.  273 

Kansas   State   Agricultural   College Manhattan,     Kans.  341 

Post  Dispatch   (Pulitzer  Pub.  Co.) 8t.  Louis,  Mo  .  543 

Radio  Service  Corp.  of  Utah Salt  Lake  City,  Utah  299 

American  Radio  Telephone  Co..  Inc Seattle,  Wash.  306 

Now  Arlington  Hotel  Co Hot  Springs.  Ark.  373 

First  Presbyterian  Church Seattle.  Wash.  455 

Examiner  Printing  Co Ban  Francisco,  Calif.  246 

State  University  of   Montana Missoula,   Montana  244 

Portable    Wireless    Telephone    Co Stockton.  Calif.  248 

Wilson  Duncan  Studios Kansas  City.  Mo.  236 

City  of  Brownsville Brownsville.  TexaB  278 

Electrio  Shop Honolulu,  Hawaii  270 

Westinghouse  Electric  A  Mfg.  Co Chicago.  III.  535 

Preston    D.    Allen Oakland. Calif.  242 

Valdemar   Jensen New   Orleans, La.  263 

Tulane    University New  Orleans  La.  275 

Ohio    Mechanics  Institute Cincinnati,  Ohio  248 

Chicago  Daily  Droverp  Journal Chicago,  111.  286 

I.   R.   Nelson   Co Newark,    N.  J.  263 

Omaha    Grain    Exchange Omaha,  Nebr.  285 

Lake  Forest  University Lake  Forest  111.,  227 

Harrisburg    Sporting   Goods    Co Harrisburg,  Pa.  266 

Asheville  Battery  Co.,  Inc Asheville,  N.  C.  254 

Bangor   Railway  A  Electric  Co Bnngor,   Me.  240 

Connecticut    Agricultural    College Sorrs.Conn.  263 

Ott  Radio.    Inc LaCroase.  Wis.  244 

Lake  Avenue  Baptist  Church Rochester.  N.  Y.  283 

Haverford   College.   Radio  Club Haverford.   Pa.  261 

Scott  High  School.  N.  W.  B.  Foley Toledo.  Ohio  270 

Victor  Talking  Machine  Co Camden.   N.  J.  224 

College  of  Wooster Wooster.  Ohio  234 

Henry   B   Joy Mt.    Clemens,    Mich.  270 

John   Magaldi,  Jr Philadelphia.  Pa.  242 

Coliseum  Place  Baptist  Church New  Orleans,  La.  263 

Allen  T.  Simmons   (Allen  Theatre) Akron,  Ohio  258 

Albert  B.  Parfet  Co Port  Huron,  Mich.  233 

A.  H.  Grebe  A  Co Richmond  Hill,  N.  Y.  315 

Hubbard  and  Co Minneapolis,  Minn.  244 

Purdue     University W.  Lafayette.  Ind.  283 

Clemson  Agric.  College Clemson  College,  8.  C.  331 

The    Dayton    Co Minneapolis.  Minn.  417 

Pennsylvania  State  Police Harrisburg,  Pa.  275 

James     Millikan     University Decatur,   111.  360 

Worth  am- Carter  Publishing  Co.   (Star  Telegram) Fort  Worth,  Texas  476 

Erner  A  Hopkins  Co Columbus,  Ohio  292 

John  H.  Stenger.  Jr Wilkea-Barre.  Pa.  254 

Western   Electrio   Co New   York.  N.Y.  491 

Irving  Vermilya Mattapoisett,  Mass.  246 

Grace    Covenant    Presbyterian     Church Richmond.  Va.  253 

Atlass  Investment  Co Chicago,  111.  226 

Blake.  A.  B Wilmington,  N.  C.  175 

Petoskey  High  School Petoekey,    Mich.  146 

Peoples  Pulpit  Asso Rossville.  N.  Y.  173 

First  Baptist  Church New  Orleans.  La.  151 

Jenks    Motor    Sales  Co Monmouth,  111.  124 

Johnstown     Radio     Co Johnstown,  Pa.  245 

Ruffner    Junior    High    School Norfolk,  Va.  222 

Washington    Light   Infantry  Co.    "B"    118th    Inf Charleston, B.C.  268 

Foster   A  McDoland Chicago.  111.  266 

Baxter  Laundry  Co G'and  Rapids,  Mich .  256 

Bliss  Electrical  School Takoma  Park  Md.  121 

Jones  Elec.  A  Radio  Mfg.  Co Baltimore  Md.  254 

A.  H.  Grebe  A  Co.,  Inc Richmond  Hill,  N.  Y.  236 

Pennsylvania     State     Police Butler,  Pa.  286 

Bell  Radio  Corporation Birmingham,  Ala.  248 

Baltimore  Radio  Exchange WlIkeB-Barre,  Pa.  231 

D.   W.    May.    Inc Newark  N.  J.  251 

Southern    Radio   Corp Charlotte.  N.  C.  275 

Westinghouse  E.  A  M.  Co Springfield,  Man.  335 

St.  Lawrence   University Canton.  N.  Y.  180 

Kaufmann    A  Baer  Co.   and  1  he  Pittsburgh  Pres Pittsburgh.  Pa.  461 

Clyde  R.  Randall New  Orleans.  La.  161 

Entrekin  Electric  Co Columbus,  Ohio  186 

Nebraska  Wesleyan  University University  Place.  Nebr.  283 

8t.     Olaf    College Northfie'd,  Minn.  336 

Sanders  A  Stayman  Co Baltimore  Md.  278 

Chesapeake  A  Potoma  Telephone  Co Washington,    D.  C.  466 

Alamo  Radio  Electric  Co San  Antonio.  Texan  163 

W.  H.  Dunwoody  Industrial  Institute Minneapolis.  Minn.  280 

State  College  of  Mines Rapid  City.  8.  Dak.  140 

Durham   A   Co Philadelphia.  Pa.  178 

University  of  Vermont Burlington, Vt.  180 

Carthage    College Carthage.HI.  246 

Charles  W.  Heibachm Allentown,  Pa.  280 

University  of  Michigan Ann  Arbor.  Mioh.  280 

Wilbur    C.    Voliva Zion,  HI.  344 

Uhalt   Radio   Co New  Orleans, La.  263 

Paul  J.  Miller Pittsburgh,  Pa.  236 

Howard    S.    Williams    (Portable) Pascagoula,  Miss.  268 

University    of    Mies Oxford,  Miss.  242 

Charles     Swars Baltimore,  Md.  229 

James   P.   Boland Ft.    Benj.   Harrison.    Ind.  266 

First    Baptist    Church Nashville  .Tenn.  236 

C.  H.  Measter Providence,  R.  I.  246 

Clark    University,    Collegiate    Dept Worcester.    Mass.  238 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


99 


Radio  Test  Trip  To  Begin  in 
August 

While  other  radio  engineers  are  ex- 
ploring and  testing  atmospheric  condi- 
tions in  the  Arctic  and  in  the  tropics, 
H.  Frank  Hopkins  and  Harvey  T.  Kelley, 
Assoc,  I.  R.  E.,  plan  to  make  an  exten- 
sive survey  of  transmitting  and  receiving 
conditions  in  America's  own  front  yard. 
They  will  leave  Chicago  some  time  during 
August  on  a  trip  through  the  territory 
west  of  the  Mississippi  River  in  an  effort 
to  trace  the  causes  of  difficult  Summer 
reception  and  discover  remedies  for 
existing  conditions. 

Their  trip  will  first  take  a  northerly 
direction,  and  will  gradually  return 
south  and  west  to  Colorado  and  Utah. 
From  there  the  two  engineers  will  head 
Northwest  to  the  state  of  Washington, 
down  the  coast  through  Oregon  and 
California,  and  eastward  through  Arizona 
New  Mexico,  Texas  and  so  on  until  they 
again  arrive  in  Chicago  about  six  months 
later. 

Their  findings  will  be  revealed  regularly 
throughout  the  long  journey,  and  it  is 
expected  they  will  be  of  great  value  to 
the  radio  public  throughout  the  country. 

The  largest  mobile  broadcasting  set 
ever  transported  in  such  a  manner  will 
be  part  of  the  radio  equipment  to  be 
carried  on  this  trip,  in  order  to  test  radio 
transmission  in  so-called  "dead  spots" 
and  in  places  where  static  disturbances 
and  other  natural  interference  prevail. 
Under  these  extremely  adverse  conditions 
an  attempt  will  be  made  to  determine 
just  what  kind  of  radio  receiving  circuit 
performs  the  best.  Several  types  of 
circuits  will  be  taken  on  the  trip  and 
tested  under  varying  atmospheric  and 
geographic  conditions. 


Findings  to  be  Broadcast 

Communication  with  Eastern  and 
Pacific  broadcasting  stations  will  be 
maintained  throughout  the  long  trek, 
which  is  to  be  made  by  automobile. 
Several  radio  stations  have  expressed 
a  desire  to  broadcast  the  findings  of  the 
expedition  to  guide  them  in  reaching 
listeners  in  isolated  districts  of  the  coun- 
try, where  difficulty  is  experienced  in 
maintaining  consistent  touch  with  broad- 
casters throughout  the  year,  and  espe- 
cially in  Summer-time. 

Mr.  Hopkins  and  Mr.  Kelley  intend 
to  devise  several  new  types  of  radio 
apparatus  to  meet  the  difficulties  they 
expect    will    confront    them.      This    new 


apparatus  will  include  both  transmitting 
and  receiving  equipment.  This  informa- 
tion will  also  be  given  to  the  radio  public 
through  RADIO  AGE,  to  guide  the 
fans  who  desire  improved  reception  or 
who  are  far  from  strong  stations  and  are 
troubled  with  such  disturbances  as 
fading,  static  and  other  radio  phenomena. 
Mr.  Hopkins  and  Mr.  Kelley  have  long 
been  identified  in  radio  circles,  ever  since 
the  days  of  the  old  spark  transmitter  and 
before  vacuum  tubes  were  used  for  re- 
ceiving purposes.  They  have  done  con- 
siderable research  work  and  development 
and  as  a  result  the  findings  of  their  trip 
should  be  of  interest  to  all  persons  con- 
nected with  radio  and  its  allied  sciences. 


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RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


WCBU       Arnold     Wireless     Supply     Co Arnold,     Pa. 

WCBX       Radio  Shop  of  Newark   (Herman   Lubinsky) Newark,   N.  J. 

WCCO       Washburn-Crosby    Co , Twin    Cities,    Minn. 

WCEE       Charles    E.    Erbstein.    Villa    Olivia near    Elgin,    III. 

WCK  Stis-Baer-Fuller    D.    G.    Co St.    Louis.    Mo. 

WCTS       C.   T.   Scherer  Co Worcester.   Mass. 

WCX         Free  Press Detroit,  Mich. 

WDAE       Tampa  Daily  Times Tampa.  Fla. 

WDAF      Kansas    City    Star Kansas    City.    Mo. 

WDAG      J.    Laurence    Martin Amarillo.  Texas 

WDAH      Trinity     Methodist     Church     (South) El     Paso.     Texas 

WDAR       Lit  Brothers Philadelphia,  Pa. 

WDA  Y      Radio    Equipment    Corp Fargo,  N.  Dak. 

WDBA       Fred  Ray Columbus,  Ga. 

WDBB      A.  H.  Waits  &  Co.,  Inc Taunton.  Mass. 

WDBC       Kirk.    Johnson    &    Co Lancaster.    Pa. 

WDBD       Herman  Edwin  Burns Martinsburg,  W.  Va. 

WDBE       Gilham-Schoen  Elec.  Co Atlantic.  Ga. 

WDBJ        Richardson  Wayland  Electric  Corp Roanoke.  Va. 

WDBK      M.  F.  Broz Cleveland.  Ohio 

WDBL      Wise.    Dept.    of    Markets Stevens  Point,  Wis. 

WDBN       Electric    Light  &   Power    Co Bangor,  Me. 

WDBO       Rollins    College    Inc Winter  Park,  Fla. 

WDBQ      Morton  Rado  Supply  Co Salem.  N.J. 

WDBR      Tremont   Temp.e    Baptist    Church Boston,    Mass. 

WDBV      The  Strand  Theatre Fort     Wayne.     Ind. 

WDBX     Otto  Baur New  York.  N.  Y. 

WDBY      North    Shore    Congregational    Church Chicago.    HI. 

WDBZ      Boy  Scouts.  City  Hall Kingstown.  N.  Y. 

WDM         Church   of  the   Covenant Washington.   D.   C. 

WDOD      Chattanooga  Radio  Co..  Inc .Chattanooga,  Tenn. 

WDWF     Dutee  Wilcox  Flint.  Inc Cranston.  R.  I. 

WDZ         J.    L.    Bush Tuscola.    HI. 

WEAA       F.  D.  Fallain Flint,  Mich. 

WEAF       American  Telephone  &  Telegraph  Co New  York,  N.Y. 

WEAH       Wichita   Board  of  Trade Wichita,   Kans. 

WEAI         Cornell     University Ithaca.  N.Y. 

WEAJ        University  of  South  Dakota Vermilion,  S.  Dak. 

WEAM  Borough  of  North  Plainfield   (W.  Gibson  Buttfield) .  .North  Plainfield,  N.  J. 

WEAN      Shepard    Co Providence,    R.    I. 

WEAO      Ohio    State    University Columbus,  Ohio 

WEAR       Goodyear    Tire    and    Rubber    Co Cleveland,  Ohio 

WEAU      Davidson    Bros.  Co Sioux  City.  Iowa 

WEA  Y       Iris  Theatre  (Will  Horowitz,  Jr.) Houston,  Texas 

WEB  Benwood  Co St.  Louis,  Mo. 

WEBA       Electric  Shop Highland  Park,   N.  J. 

WEBC       Walter  Cecil  Bridges Superior.  Wis. 

WEBD       Electrical   Equipment  and  Service  Co Anderson,   Ind. 

WEBE       Roy  W.  Walker Cambridge,  Ohio 

WEBH       Edgewater  Beach  Hotel.  Chicago  Evening  Post  Station Chicago, 111. 

WEBJ        Third  Avenue  Railway  Co New  York,    N.  Y. 

WEBM      Radio     Corporation     of    America Portable 

WEBP       E.  B.  Pedicord New  Orleans.  La. 

WEBT      The  Dayton  Coop.  Industrial  High  School Dayton.  Ohio 

WEBW     Beloit  College BeloitWia. 

WEEI         The  Edison  Electric  Illuminating  Co Boston,  Mass. 

WEHS       Robert  E.  Hughes Evanston,  III. 

WEMC Barrien  Springs,  Mich. 

WEN  R      All-American   Radio  Corporation Chicago,   Illinois 

WEW         St.     Louis    University St.  Louis,  Mo. 

WFAA       Dallas    News    &    Dallas    Journal Dallas.    Tex. 

WFAM     Times  Publishing  Co St.  Cloud,  Minn. 

WFAV  University  of  Nebraska,  Department  of  Electrical  Engineering,  Lincoln,  Nebr. 

WFBC       First     Bapitist     Church Knoxville,  Tenn. 

WFBD      Gethsemane  Baptist  Church Philadelphia,  Pa. 

WFBE       John  Van  De  Walle Seymour.  Ind. 

WFBG      The  Wm.  F.  Cable  Co Altoona.  Pa. 

WFBH       Concourse  Radio  Coporation New  York,  N.  Y. 

WFBJ        St  John's  University Collegeville,  Minn. 

WFBQ     Wynne  Radio  Co Raleigh,  N.C. 

WFBR       Fifth  Inf.  Md.  Nat'1  Guard,  5th  Reg.  Armory Baltimore,  Md. 

WFBW      Ains  worth -Gates  Radio  Co Cincinnati,  Ohio 

WFBY      Signal  Officer Ft.  Ben  Harrison,  Ind. 

WFBZ       Knox  College Galesburg,  HI. 

WFI  Strawbridge  and  Clothier Philadelphia,  Pa. 

WFKB       Francis  K.  Bridgman Chicago,  III. 

WFUV       G.  Pearson  Ward Springfield,  Mo. 

WFUW     Earl  William  Lewis Moberly,  Mo. 

WGAL       Lancaster  Electric  Supply  &  Construction  Co Lancaster,  Pa. 

WGAQ     YoureeHotel Shreveport,  La. 

WGAZ      South  Bend  Tribune South  Bend,  Ind.. 

WGBB      Harry  H.  Carman,  217  Bedell  St Freeport,  N.  Y. 

WGBC      First   Baptist  Church .Memphis,   Tenn. 

WGBF      Fink    Furniture    Co Evansville.Ind. 

WGBG      Brietenbach's    Radio   Shop Thrifton.    Va, 

WGBH      Fall    River    Herald    Pub.  Co (Portable)  Fall  River,  Mass. 

WGBI        Frank   6.  Megargee Scranton,  Pa. 

WGBK      Lawrence  Campbell Johnstown.  Pa. 

WGBM     Theodore  N.  Saaty Providence,  R.  I. 

WGBL       Elyria  Radio  Asso.  (Albert  H.  Ernst) Elyria,  Ohio 

WGBQ      Stout  Institute Menominee,  "Wis. 

WGBR      Marshfield  Broadcasting  Assn Marshfield,  Wis. 

WGBS       Gimbel  Brothers New  York.  N.  Y. 

WGBT      Furman    University Greenville.  S.  C. 

WGBX      University  of  Maine Orono.  Me. 

WGBY      Progress  Sales  Co R,  R,  No.  2 

WGES       Come  Electrical  School Oak  Park.  Ill, 

WGI  American  R.  &  R.  Co Medford  Hillside,  Mass. 

WGMU    A.  H.  Grebe  &  Co.,  Inc..  Portable Richmond  Hill,  N.  Y. 

WGN  The    Tribune    Co Chicago.    111. 

WGR        Federal  T.  and  T.  Co Buffalo,  N.  Y. 

WG  Y         General    Elec.    Co Schenectady  N.  Y. 

WHA  University    of    Wisconsin Madison,    Wis. 

WHAD      Marquette  University Milwaukee,  Wis. 

WHAG      University  of   Cincinnati Cincinnati,   Ohio 

WHAH      Hafer  Supply  Co Joplin.  Mo. 

WHAM     University  of  Rochester  (Eastman  School  of  Music) Rochester,  N.  Y. 

WH AP       H.  Alvin  Simmons.  290  Flatbush  Ave Brooklyn.  N.  Y. 

WHAR      Seaside  House Atlantic  City.  N.  J. 

WHAS      Courier- Journal  &  Louisville  Times Louisville,    Ky. 

WHAV       Wilmington  Electrical  Specialty  Co Wilmington.   Del. 

WHAZ '     Rensselaer  Polytechnic    Institute '.' Troy,  N.  Y. 

WHB         Sweeney    School    Co Kansas    City,    Mo. 

WHBA      C.  C.  Shaffer Oil  City.  Pa. 

WHBB      BTobel  s  Store Stevens   Point,   Wis. 

WHBC      Rev.  E.  P.  Graham Canton.  Ohio 

WHBD     Chas.  W.  Howard Bellefontaine,  Ohio 

WHBF      Beardsley  Specialty  Company Rock  Island,  Illinois 

WHBG      John    S.    Skane Harrisburg,    Pa. 

WHBH      Culver    Military    Academy Culver,    Ind. 

WHBJ       Lauer  Auto  Co Ft.  Wayne.  Ind. 

WHBK      Franklin   St.   Garage,   Inc Ellsworth,    Maine 

WHBL      James  H.  Slusser Logansport,  Ind. 

WHBM     C.  L.  Carroll.  Portable  Station Chicago,  HI. 

WHBN      First  Ave.  Methodist  Church St.  Petersburg.   Florida 

WHBO      Y,  M.  C.  A..  Summer  Street Pawtucket.  Rhode  Island 

WHBP      Johnstown  Automobile  Co Johsntown.  Pennsylvania 

WHBQ     St.  John's  M.  E.  CtiuTch  South Memphis.  Tenn. 

WHBR     Scientifio  Electrio  &  Mfg.  Co.,  3664  Vine  St Cincinnati.  Ohio 

WHBS       Edward  Wm.  Locke Mechaniceburg,  Ohio 

WHBU      B.   L.  Bing's  Sons Anderson,   Ind. 

WHBV       Fred  Ray's  Radio  Shop Columbus.  Ga. 

WHBW     D.     R.     Kienzle ; Philadelphia,  Pa. 

WHBX     J.    W.   Bowser ■: Punxsutawney,   Pa. 

WHBY      St.    Norbert  s   College j  .West  De  Pore.  Wis. 

WHEC       Hickson  Electric  Co.,  Inc Rochester,  N.  Y. 

WHK         Radiovox  Company Cleveland,  Ohio 

WHN         George  Schubert New  York,  N.  Y. 

WHO  Bankers' Life  Co Des  Moines.  la. 

WHT  Radiophone  Broadcasting  Corporation Deerfield.  111. 

WIAD        Howard   R.   Miller. Philadelphia,   Pa. 

WIAK       Journal-Stockman  Co Omaha,  Nebr. 

WIAQ       Chronic!*    Publishing    Co Marion,  Ind. 


254 

WIAS 

233 

WIBA 

416 

WIBC 

278 

WIBD 

275 

W1BE 

268 

WIBF 

516 

WIBG 

365 

WIBO 

365 

WIBH 

263 

WIBI 

268 

WIBJ 

394 

WIBK 

244 

WIBL 

236 

WIBP 

229 

WIBR 

258 

WIBS 

268 

278 

WIBQ 

229 

WIL 

227 

WIP 

278 

WJAB 

252 

WJAD 

240 

WJAG 

234 

WJAK 

256 

WJAM 

258 

WJAR 

233 

WJAS 

258 

WJA2 

233 

WJBA 

234 

WJBB 

256 

WJBC 

441 

WJBD 

278 

WJB1 

250 

WJD 

485 

WJJD 

280 

WJY 

286 

WJZ 

283 

WKAA 

286 

WKAD 

273 

WKAP 

293 

WKAQ 

389 

WKAR 

275 

WKAV 

270 

WKBE 

273 

WKBF 

233 

WKBG 

242 

WKY 

246 

WLAG 

248 

WLAL 

370 

WLAP 

273 

WLAQ 

226 

WLAX 

280 

WLB 

270 

WLBL 

283 

WLS 

475 

WLTS 

205 

WLW 

285 

WMAC 

266 

WMAF 

280 

WMAK 

472 

WMAL 

273 

WMAN 

275 

WMAQ 

250 

WMAV 

234 

WMAY 

226 

WMAZ 

261 

WMBB 

273 

WMBF 

236 

WMC 

255 

WMCA 

452 

WMH 

309 

WNAB 

258 

WNAC 

254 

WNAD 

394 

WNAL 

217 

WNAP 

252 

WNAR 

233 

WNAT 

248 

WNAX 

252 

WNYC 

360 

WOAC 

244 

WOAE 

266 

WOAG 

217 

WOAI 

226 

WOAN 

209 

WOAO 

240 

WOAR 

248 

WOAT 

234 

WOAV 

227 

WOAW 

234 

WOAX 

229 

woe 

315 

WOCL 

236 

WODA 

252 

WOI 

218 

WOO 

250 

WOR 

261 

WORD 

236 

WOS 

370 

WOWL 

319 

WOWO 

379 

WPAB 

535 

WPAC 

280 

WPAJ 

222 

WPAK 

283 

WPAL 

278 

WPAZ 

240 

WPG 

275 

WQAA 

399 

WQAC 

360 

WQAE 

385 

WQAM 

365 

WQAN 

250 

WQAO 

240 

WQAS 

245 

WQJ 

222 

WRAA 

222 

WRAF 

231 

WRAK 

222 

WRAM 

234 

WRAQ 

231 

WRAV 

220 

WRAW 

233 

WRAX 

258 

WRBC 

231 

WRC 

256 

WREO 

233 

WRHF 

216 

WRNY 

208 

WRK 

218 

WRL 

244 

WRM 

•215 

WRR 

213 

WRW 

250 

WSAC 

258 

WSAG 

273 

WSAI 

360 

WSAJ 

526 

WSAN 

238 

WSAP 

254 

WSAR 

273 

WSAV 

226 

WSAY 

Home  Electric  Co Burlington,  Iowa 

The    Capital-Times    Studio Madison.  Wia. 

L.  M.  Tate  Post.  No.  39.  Veterans  of  Foreign  Wars St.  Petersburg,  Florida 

X-L  Radio  Service Joliet.  Illinois 

Martinsburg  Radio  Broadcasting  Co Martinsburg,  W.  Va 

S.  P.  Miller  Dance  Activities Wheatland,  Wise. 

St.   Paul's  Protestant   Episcopal  Church Elkins   Park,  Pa. 

Nelson  Brothers Chicago,  HI. 

Elite  Radio  Stores New  Bedford,  Mass. 

Frederick  B.  Zittell.  Jr Flushing,   N.  Y. 

C.  L.   Carrell   (Portable) Chicago,  111. 

University  of  Toledo Toledo,  Ohio 

McDonald  Radio  Co.,  Portable  Station Joliet,  HI.  2157 

First  Presbyterian  Church Meridian,  Miss.     210 

Thurman  A.  Owings Weirton,  W.  Va.     246 

New  Jersey  National  Guard,  Hdqrs.  Co.  57th  Inf.  Brig..  921  Edgwood  Road, 

Elizabeth,  N.  J.  202.6 

F.  M.  Schmidt Farina.  111.     205 

Continental  Electric  Supply  Co Washington,  D.  C.     360 

Gimbel    Bros Philadelphia,    Pa.     509 

American   Electric   Co Lincoln,    Nebr.     229 

Jackson's   Radio   Engineering   Laboratories Waco     Texas 

Norfolk  Daily  News Norfolk,   Nebr. 

Clifford   L.   White Greentown,   Iowa 

D.  M.  Perham Cedar  Rapids,  Iowa 

The  Outlet  Co.  (J.  Samuels  &  Bro.) Providence,  R.  I. 

Pittsburgh  Radio  Supply  House Pittsburgh.    Pa. 

Chicago    Radio    Laboratory Chicago,    HI. 

D.  H.  Lentz,  Jr Joliet   HI 

L.  W.  McClurg St.  Petersburg,  Fla. 

Hummer  Furniture  Co LaSalle,  111. 

Ashland   Broadcasting   Committee Ashland,   Wise. 

H.  M.  Couch Joliet,  111.  2142 

Denison    University Graniteville,    Ohio     229 

Supr.-me  Lodge,   Loyal  Order  of  Moose Mooseheart,  111. 

Radio  Corp.  of  Ama New  York,  N.  Y. 

Radio  Corp.  of  Ama New  York,  N.  Y. 

H.    F.    Paar Cedar    Rapids,    Iowa 

Chas.  Looff  (Crescent  Park) East  Providence,  R.  I. 

Dutee    W.    Flint Cranston,    R.    I. 

Radio  Corp.  of  Porto  Rico San  Juan,  P.  R. 

Michigan     Agriculture     College East     Lansing,     Mich. 

Laconia    Radio    Club Laconia,    N.    H. 

K.  &  B.  Electric  Co Webster,  Massachusetts 

Dutee  Wilcox  Flint Cransten,  Rhode  Island 

C.  L.  Carrel,  Portable Chicago,  111. 

Why   Radio  shop Okla.  City.   Okla. 

Cutting  &  Washington  Radio  Corp Minneapolis,  Minn. 

First  Christian  Church Tulsa,  Okla. 

Wm.  V.  Jordan Louisville,  Ky. 

Arthur  E.  Shilling Kalamazoo,  Mich. 

Putnam  Electric  Co Greencastle,  Ind. 

University  of  Minnesota Minneapolis,  Minn. 

Wisconsin  State   Dept.   of   Markets Stevenspoint,   Wis. 

Sears    Roebuck    &    Co Chicago,    HI.     _ 

Lane  Technical  High  School,  1225  Sedgwick  Road Chicago.  IU.     258 

Crosley  Mfg.  Co Cincinnati,  Ohio     422 

J.  Edw.  Page  (Olive  B.  Meredith Cazenovia,  N.  Y. 

Round    Hills    Radio    Corp Dartmouth.    Mass. 

Norton  Laboratories Lookport,  N.  Y. 


283 
236 
222 
200 
210 
231 
222 
226 
209 
219 
216 
205 


352 
283 
254 
268 
306 
286 
268 
207 
207 
234 
233 


303 
455 
455 
278 
240 
234 
340 
285 
254 
231 
286 
216 
275 
417 
250 
286 
283 
231 
278 
278 
344 


261 

360 
273 


Trenton'  Hardware   Co Trenton,    N.   J.  256 

First    Baptist    Church Columbus,  Ohio  286 

Chicago    Daily    News Chicago,  HL  447 

Alabama    Polytechnic    Institute Auburn,  Ala.  250 

Kingshighway    Presbyterian    Church St.    Louis,    Mo.  280 

Mercer    University Macon,    Ga.  261 

Trianon    Ball    Room Chicago,  IU.  250 

Miami    Beach,    Fla.  384 

Commercial     Appeal Memphis,  Tenn.  503 

Hotel  McAlpin  (Greeley  Square  Hotel  Co.) New  York  City  341 

Ainsworth-Gates    Radio    Co Cincinnati,  O.  321 

The  Shepard  Stores Boston,  Mass.  250 

Shepard  Stores Boston,  Mass.  284 

University  of  Oklahoma Norman,   Okla.  258 

Omaha    Central    High    School Omaha,  Nebr.  255 

Wittenberg  College Springfield,  Ohio  271 

First   Christian    Church Butler,    Mo.  230 

Lennig  Brothers  Co.  (Frederick  Lennig) Philadelphia,  Pa.  254 

Dakota   Radio  Apparatus  Co Yankton,   S.   Dak.  248 

Dept.  of  Plant  and  Structures New  York,  N.  Y.  526 

Page  Organ  Co Lima,  Ohio  260 

Midland  College Fremont,  Nebr.  280 

Apollo    Theater     (Belvidere    Amusement    Co.) Belvidere.  III.  274 

Southern  Equipment  Co San  Antonio.  Texaa  392 

Vaughn  Conservatory  of  Music  (James  D.  Vaughn) Lawrenceburg.  Tenn.  280 

Lyradion    Mfg.    Co Mishawaka,    Ind.  369 

Lundskow,  Henry  P Kenosha,  Wis.  225 

Boyd  M.  Hamp Wilmington,  Del.  360 

Pennsylvania   National   Guard,   2d   Battalion.    112th   Infantry Erie,   Pa.  242 

Woodmen  of  the  World Omaha,  Nebraska  526 

Franklyn  J.   Wolff Trenton,  N.J.  240 

Palmer   School   of   Chiropractic Davenport,    Iowa  484 

Hotel  Jamestown,   Inc Jamestown,   N.  Y.  275 

James  K.  O'Dea Paterson,  New  Jersey  203 

Iowa  State  College Amea,  la.  207 

John    Wanamaker Philadelphia,    Pa.  509 

L.  Bamberger  and  Co Newark,  N.  J.  405 

Peoples     Pulpit    Assn Batavia,  HI.  275 

State    Marketing    Bureau Jefferson  City,  Mo.  440 

Owl  Battery  Company New  Orleans,  La.  270 

Main  Auto  Supply  Co Ft.  Wayne,  Ind.  227 

Pennsylvania    State    College State  College.  Pa.  283 

Donaldson    Radio    Co Okmulgee,  Okla.  360 

Doolittle  Radio  Corp New  Haven,  Conn,  268 

North  Dakota  Agricultural  College Agricultural  College,  N.  D.  283 

Superior   Radio    &   Telephone   Equipment   Co Columbus.    Ohio  286 

John  R.  Koch  (Dr.) Charleston.  W.  Va.  273 

The  Municipality  of  Atlantic  City Atlantio  City,  N.  J.  300 

Horace    A.    Beale,    Jr Parkersburg,    Pa.  270 

E.  B.  Gish Amarillo,  Texas  234 

Moore  Radio  News  Station   (Edmund  B.  Moore) Springfield,  Vt.  275 

Electrical    Equipment    Co Miami,  Fla.  283 

Scranton     Times Bcranton,     Pa.  280 

Calvary  Baptist  Church New  York.  N.  Y.  360 

Prince- Walter  Co Lowell,  Mass.  266 

Calumet  Rainbo  Broadcasting  Co Chicago,   HI.  447 

The  Rice  Institute Houston.  Texas  256 

The  Radio  Club  (Inc.) Laporte,  Ind:  224 

Economy  Light  Co Escanaba,  Mich  256 

Lombard  College Galesburg,  HI.  244 

St.  Louis  Radio  Service  Co. .-. St.  Louis,  Mo.  263 

Antioch   College Yellow  Springs,   Ohio  242 

Avenue  Radio  Shop  (Horace  D.  Good) Reading,  Pa.  238 

Flaxon's   Garage Gloucester   City.    N.    J.  268 

Imanuel  Lutheran  Church Valparaiso.  Ind.  278 

Radio  Corp.  of  Ama ; Washington,  D.  C.  468 

Reo  Motor  Car  Co Lansing,  Mioh.  286 

Washington  Radio  Hospital  Fund Washington,  D.  C.  256 

Experimenter  Publishing  Co New  York,  N.  Y.  258 

Doron    Bros Hamilton,    Ohio  360 

Union  College , Schenectady,   N.  Y.  270 

University  of  Illinois ; Urbana,  HI.  273 

Police  and  Fire  Signal  Department Dallas,  Texas  261 

Tarrytown  Radio  Res.  Laba Tarrytown,  N.  Y.  273 

Clemson  Agricultural  College Clemson  College.  S.  C  336 

Loren  Vanderbeck   Davis St.   Petersburg,   Fla.  264 

United  States  Playing  Cards  Co Cincinnati.  Ohio  325 

Grove  City  College Grove  City,  Pa.  258 

AHentown  Call  Publishing  Co Allentown,  Pa.  229 

Seventh  Day  Adventist  Church New  York,  N.  Y.  263 

Doughty  A  Welch  Electrical  Co Fall  River,  Mass.  254 

C.  W.  Vick  Radio  Construction  Co Houston,  Texas  360 

Irving  Austin  (Port  Chester  Chamber  of  Commerce).  .  .Port  Cheater,  N.  Y.  239 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


101 


Standard  Radio  Receivers 


(Continued  from  page  87) 


The  Anylite  King  Cole 
Receivers 

Anylite  King  Cole  radio  sets  will  be 
made  for  external  batteries  and  may  be 
used  with  any  standard  tubes.  The 
cabinet  is  brown  mahogany  and  the 
panel  black  formica  with  gold  trimmings. 

An  outstanding  feature  is  simplicity 
of  control  by  means  of  two  vernier  dials. 
All  reception  is  possible  on  a  loud  speaker. 
Selectivity  is  unsurpassed  by  any  set, 
and  coast  to  coast  reception  is  possible 
under  favorable  weather  conditions. 

The  small  amount  of  B  battery  current, 
as  low  as  .002  amperes,  assures  long  life 
of  batteries  and  low  upkeep  expense. 

The  set  is  non-radiating  and  all  parts 
are  extremely  efficient.  The  coils  are 
by  far  the  most  efficient  we  havejjbeen 
able  to  secure. 

King  Cole  sets  are  guaranteed  against 
defective  material  and  workmanship, 
and  when  used  with  any  good  loud 
speaker  will  give  ample  volume  and  ex- 
cellent  tones. 


Anylite  King  Cole  audio  frequency 
transformers  are  designed  to  give  strong 
amplification  and  faithful  reproduction 
over  the  entire  musical  range.  These 
transformers  may  be  used  with  all  stand- 
ard tubes  and  large,  plainly  marked 
terminals  provide  for  secure  connec- 
tions. The  cases  are  handsomely  finished 
in  black  enamel  and  serve  as  a_shield  for 
the  coil. 

King  Cole  Transformers  have  been 
developed  after  exhaustive  research  on 
the  part  of  the  Anylite  Engineers/ and 
will  give  complete  satisfaction. 


The  Five  Tube 
Set  which 


/ 


startled 
the  World 

FRESHMAN 


The  Greatest  Value 
Ever  Offered  in  A 
Radio  Receiving  S*t 


Hfie^raffic  Cop 

jrjfc       Trap  to  your  Radio  Set  Vo 
X~f        and"Police"yourrecep- 
tion.      Regulate  traffic. 
Guaranteed  to  tune  out 
any  interfering  station. 
Widely    imitated    but 
*  never  equalled.      The 
original    and    only  suc- 
cessful   WAVE    TRAP. 
Now  in   its  third   year. 
Sent  Postpaid  upon  re- 
ceipt of  SS.50  or  C.  O.  D. 
plus  postage.  Send  for  Free  Booklet 
FERBEND  ELECTRIC  CO. 
l  I.  So.  Water  St.        •       Chicago 


The  Blair  Receiver 

Employing  Resistance-Coupled  Audio 

Amplification  and  Tuned 

Radio  Frequency 

The  Blair  Six  Tube  Receiver,  employ- 
ing two  stages  of  tuned  radio  frequency, 
a  detector  and  three  stages  of  resistance- 
coupled  audio  amplification,  is  now 
available  to  the  American  market. 

The  Blair  Receiver  is  the  result  of 
years  of  experimentation  in  both  British 
and  American  laboratories  and  repre- 
sents the  perfected  combination  of  these 
two  highly  efficient  methods  of  ampli- 
fication; namely,  tuned  radio  frequency 
for  distance  and  selectivity,  and  re- 
sistance-coupled^audiOjfor  tone*quality. 


The  result  is  the  surpassing  clarity  of 
delivery  for  which  resistance-coupled 
amplification  is  noted,  together  with 
distance  and  volume  in  any  quantity 
desired. 

Heretofore,  the  manufacturers  of  the 
Blair  Receiver  have  confined  their  sales 
efforts  to  the  British  market,  and  they 
are  now  one  of  the  largest  exporters  of 
radio  receiving  sets  in  this  country. 

In  choosing  a  receiving  set  for  his 
Majesty  .  King  George  V,  the  British 
engineers  chose  resistance-coupled  ampli- 
fication. 

The  Blair  Receiver  comes  in  mahogany 
or  walnut  cabinets  with  sloping  panels 
and  three  dials.     The  list  price  is  §75.00. 

This  set  is  being  manufactured  by 
the  Blair  Radio  Laboratories,  23rd 
Street  &  6th  Avenue,  New  York  City. 


Foreign  Visitors  at  N.  Y. 
Radio  Show 

The  undoubted  leadership  which  the 
radio  industry  of  the  United  States  main- 
tains over  those  of  other  nations  is 
reflected  by  the  many  foreign  visitors  who 
ire  planning  to  come  to  this  country  for 
the  Exposition  to  be  held  in  Grand  Central 
Palace  during  September. 

A  radio  Festa,  in  which  the  leading 
stars  of  the  microphone  will  participate, 
is  planned  for  theJFourth  Annual  National 
Radio  ^Exposition  by  S.  L.  Rothafel, 
("Roxy,";  who  will  have  charge  of  the 
entertainment  program  to  be  broadcast 
from  Grand  Central  Palace  during  Expo- 
sition Week. 


SEND  NO  MONEY! 

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Printed  Free  on  Thank  You  Cards 
YOU  like.  Stations  glad- 
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i'rrid  no  mo^y-pay  POil 

RADIO  PRINTERS,  Dept.  C202,  Marengo.  111. 

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Tested  and  used  by  morethan  50  set  manu- 
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Radiall  Company* 

Dept.FLA.-  S,  50  Franklin  St.,  New  York  City 
Write  for 

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Wanted 

to  start  now  in  the  fastest 
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THE  * 

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RECEIVER 

is  the  peerless  seller  of  them 
all.  Think!  Only  two  orders 
weekly  means  $600  per  month. 
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The  Set  with  the  Marvelous 
Tone  and  Volume  Supreme, 
the  Distance  getter  of  them 
all.  Write  now,  today,  for 
our  liberal  15-day  trial  offer 
and  protected  territory. 

THIELEN     Manufacturer 
1207  North  Shore  Ave.,  Chicago, 


"Get  Away  From 
Me  Boys,  You  Bother  Me" 

isafavoriteofours.  Our  Salespeaker  will 
be  a  favorite  of  yours.  Dealers  write  for  it. 
HUDSON-ROSS— 116S.  WellsSt. 
Chicago 


102 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


WSAZ 

WSB 

WSBC 

WSKC 

WSMB 

WSMH 

WSMK 

WSOE 

WSRF 

WSTA 

WSUI 

WTAB 

WTAC 

WTAL 

WTAP 

WTAQ 


CFAC 

CFCA 

CFCF 

CFCH 

CFCJ 

FCKC 

CFCN 

CFCQ 

CFCR 

CFCT 

CFCU 

CFCW 

CFDC 

CFHC 

CFLC 

CFQC 

CFRC 

CFUC 

CFXC 

CFYC 

CHAC 

CHBC 

CHCB 

CHCD 

CHCE 

CHCL 

CHCM 

CHCS 

CHIC 

CHNC 


PWX 

2DW 

2AB 

20K 

2BY 

2CX 

2EV 

2TW 

2HC 

2LC 

2KD 

2MN 

2MG 

2JD 


2LO 
51 T 
SWA 
•BM 
2ZY 


Chas    Electric  Shop Pomeroy.  Ohio  2S8  WTAR 

Atlanta  Journal Atlanta.  Ga.  428  WTAS 

World  Battery  Co..  1219  S.  Wabash  Ave Chicago..  111.  209.7  WTAT 

World's  Star  Knitting  Co Bay  City.  Mich.  261  WTAW 

Saenger  Amusement  Co.  and  Maison  Blanche  Co New  Orleans,  La.  319  WTAX 

Shattuck  Musio   House Owosso.   Mich.  240  WTAZ 

S.  M.  K.   Radio  Corp Dayton,  Ohio  275  WTHS 

School  of  Engineering Milwaukee.  Wis.  246  WTG 

Hardem  Salts  and  Service Broadlands,  111.  233  WTIC 

Camp   Marienield Chesham,   N.   H.  229  WTX 

State  University  ol  Iowa Iowa  City.  Iowa  498  WWAD 

Fall  River  Daily  Herald  Publishing  Co.    .    FaU  River,  Mass.  248  WWAE 

Penn  Traffio  Co Johnstown.   Pa.  360  WWI 

Toledo  Radio  4  Electric  Co Toledo.  Ohio  252  WWJ 

Cambridge  Radio  4  Electric  Co Cambridge.  III.  241  WWL 

S    H    Van  Gordon  4  Son Osseo.  Wis.  220  WWOA 


Reliance    Electric    Co Norfolk.  Va. 

Charles  E.  Erbstein Elgin.   111. 

Edison  Electric  Illuminating  Co (portable)   Boston,  Mass. 

Agricultural  4  Mechanical  College  of  Texas College  Station.  Texas 

Williams    Hardware    Co Streator.  111. 

Thomas  J.   McOuire LambertvUle,  N.  J. 

Flint    Senior    High    School Flint.   Mioh. 

Kansas  State  Agricultural  College Manhattan,  Kane. 

Travelers  Insurance  Co Hartford,  Conn. 

H.  Q.  Seal  Co Chicago,  111. 

Wright  4  Wright  (Inc.) Philadelphia.  Pa. 

The  Alamo  Ball  Room Joliet.  111. 

Ford   Motor  Co Dearborn,  Mich. 

Detroit    News    (Evening    Newe    Assn.) Detroit,    Mioh. 

Loyola    University New    Orleans,    La. 

Michigan  College  of  Mines Houghton,  Mien. 


280 
JOS 
244 
280 
231 
283 
218 
273 
323 
268 
360 
242 
273 
3S2 
26S 
244 


Canadian  Stations 


Calgary     Herald , Calgary,  Alberta 

Star  Pub.  4  Prig.  Co Toronto.  Ontario 

Marconi  Wireless  Teles   Co.  Canada Montreal.  Quebec 

Abitibi  Power  &  Paper  Co Iroquois  Falla,  Ont. 

La  Cie  da  L'Evenement Quebec,  Quebec 

Radio  Supply  Co Edmonton,  Alberta 

W.  W.  Grant  Radio  (Ltd.) Calgary,  Alberta 

Radio  Specialties    (Ltd.) Vancouver.   B,   C. 

Laurentide   Air   Service Sudbury,   Ont. 

Victoria   City   Temple Victoria,    B.   C. 

The  Jack  Elliott  Radio  Limited Hamilton,  Ont. 

The    Radio   Shop London,     Ont. 

Sparlta     Co Nanaimo,  B.  C. 

Henry   Birks    <fc    Sons Calgary,    Alta. 

Chaa.   Guy  Hunter 661   Adelaide  St..   London.  Ont. 

The  Electric  Shop   (Ltd.) Saskatoon,   Saskatchewan 

Queens     University Kingston,  Ontario 

University    of    Montreal Montreal,    Quebec 

Westminster   Trust   Co New    Westminster,    B.    C. 

Victor    Wentworth    Odium Vancouver,    B.    C. 

Radio    Engineers Halifax,    Nova    Scotia 

Albertan   Publishing    Co Calgary,   Alberta 

Marconi    Company Toronto,  Ont. 

Canadian  Wireless  A  Elec.  Co Quebec,  Quebec 

Western  Canada  Radio  Sup.  (Ltd.) Victoria,  B.  C. 

Vancouver  Merchants  Exchange : Vancouver,  B.  C. 

Riley  4  McCormack Calgary,  Alberta 

The   Hamilton  Spectator Hamilton,   Ont. 

Northern    Electric    Co Toronto,    Ont. 

Toronto    Radio     Research Toronto.  Ont. 


430 

CHXC 

400 

CHYC 

440 

CJBC 

400 

CJCA 

410 

CJGC 

410 

CJCD 

440 

CJCE 

450 

CJCF 

410 

CJCI 

410 

CJCK 

410 

CJCM 

420 

CJCN 

430 

CJSC 

440 

CKAC 

410 

CKCD 

400 

CKCE 

450 

CKCK 

400 

CKCO 

440 

CKCX 

400 

CKLC 

400 

CKOC 

410 

CNRA 

410 

CNRC 

410 

CNRE 

400 

CNRM 

440 

CNRO 

415 

CNRR 

420 

CNRS 

356 

CNRT 

330 

CNRW 

J.    R.    Booth Ottawa,  Ont.  435 

Northern  Electric  Co Montreal,  Quebec  410 

Jarvis   Baptist  Church Toronto,   Ont.  313 

Edmonton  Journal Edmonton,  Alberta  455 

London  Free  Press  Prtg.  Co London,  Ont.  430 

T.    Eaton    Co Toronto,    Ont.  410 

Sprott-Shaw    Radio    Co Vancouver.    B.    C.  420 

The   Newe   Record Kitchener,   Ont.  295 

Maritime  Radio  Corp St.  John,  New  Brunswiok  400 

Radio  Corp-  of  Calgary Calgary,  Alta.  316 

J.  L.  Phillipe Mont  Joli.  Quebsc  430 

Simons  Agnew  4  Co Toronto.  Ont.  410 

Evening    Telegram Toronto,  Ont.  430 

La  Presse  Pub.  Co Montreal.  Quebec  430 

Vancouver  Daily  Province Vancouver,    B.  C.  410 

Canadian  Independ.  Telephone  Co Toronto,  Ont.  450 

Leader    Pub.    Co Rtgina,    Saskatchewan  420 

Ottawa    Radio    Association Ottawa,    Ont.  440 

P.  Burns  4  Co Calgary,  Alberta  440 

Wilkinson   Electric  Company Calgary,  Alberta  400 

Wentworth    Radio   Supply   Co Hamilton,   Ont.  410 

Canadian  National  Railways Moncton,  N.  B.  313 

Canadian  National  Railways Calgary.  Canada  357 

Canadian  National  Railways Edmonton,  Alta."  "455 


Canadian  National  Railways Montreal,  P.  Q. 

Canadian  National  Railways Ottawa,  Ont. 

Canadian  National  Railways Retina,  Sash . 

Canadian  National  Railways Saskatoon,  Sash. 

Canadian  National  Railways Toronto,  Ont. 

Canadian  National  Railways Winnipeg,  Man. 


Cuban  Stations 


Cuban  Telephon   Co Habana 

Pedro  Zayas Habana 

Alberto  S.  de  Bustamante Habana 

Mario  Garcia  Velea Habana 

Frederick  W.  Borton Habana 

Frederick  W.  Borton Habana 

Westinghouae  Elec.  Co Habana 

Roberto  E.  Ramiree Habana 

Heraldo  de  Cuba Habana 

Luis  Casas Habana 

E.  Sanchez  de  Fuentes ■ Habana 

Fausto  Simon Habana 

Manuel  G.  Salas Habana 

Raul  Pares  Falcon Habana 


400 

2K 

300 

2HS 

240 

20L 

360 

2WW 

260 

5EV 

320 

6KW 

220 

6KJ 

230 

6CX 

275 

6DW 

250 

6BY 

350 

6AZ 

270 

8BY 

280 

SFU 

180 

8DW 

Al vara  Daaa Habana 

Julio  Power Habana 

Oscar  Collado Habana 

Amadeo  Saenz Habana 

Leopoldo  E.  Figueroa ; Colon 

Frank  H.  Jones Tuinuou 

Frank  H.  Hones Tuinucu 

Antonio  T.  Figueroa Ciennegos 

Eduardo  Terry Ciennegos 

Jose  Ganduxe Ciennegos 

Valentin  UUivarri Ciennegos 

Alberto  Ravelo Stgo.  de  Cuba 

Andres  Vinnet Stgo.  de  Cuba 

Pedro  C.  Andus Stgo.  de  Cuba 


410 
430 
312 

329 
357 
384 


200 
180 
290 
210 
360 
340 
275 
170 
225 
300 
200 
250 
225 
273 


European  Broadcasting  Stations 


British  Stations 


London 365  5NO 

Birmingham 475  5SC 

Cardiff 350  2BD 

Bournemouth 385  6SL 

Manchester 375 


Newcastle 400 

Glasgow 420 

Aberdeen 492 

Sheffield  {relay  station) 303 


French  Stations 


Lyon, 740 

Paris  (Eiffel  Tower) 2,600 


End  your  Radio  Troubles  for  30c  in  Stamps 


We  have  laid  aside  a  limited  number  of  back  issues  of  RADIO  AGE  for  your  use. 
in  these  volumes.  Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired, 
store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 


Below  are  listed  hookups  to  be  found 
The  supply  is  limited,  so  enrich  your 


Wave   Traps — -Eliminators 


January,  1924 

— Tuning   Out    Interference 

—Filters. 

— A  Junior  Super-Heterodyne. 

— Push-Pull  Amplifier. 

— Rosenbloom  Circuit. 

March.  1924 

— An  Eight-Tube  Super- Heterodyne. 
— A  simple,  low  loss  tuner. 
— A  Tuned  Radio  Frequency  Amplifier. 
— Simp  e  Reflex  Set. 

April,  1924 

— An  Efficient  Super- Heterodyne  (fully  illustrated). 

— A  Ten-Dollar  Receiver. 

— Anti-Body  Capacity  Hookups. 

— Reflexing  the  Three-Circuit  Tuner. 

— Index  and  first  two  installments  of  Radio  Age  Data  Sheets. 

May,  1924 

— Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

— Important    Factors    in    Constructing   a    Super-Heterodyne. 

— A  Universal  Amplifier. 

— A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 

—  Sadicj  Age  Data  Sheets. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 
— Operating  Detector  Tube  by  Grid  Bias. 
—A  Three-Tube  Wiiard  Circuit. 
—Data  Sheets. 

RADIO  AGE,  INC., 


August,  1924 

— Breaking  Into  Radio  Without  a  Diagram. 

— The  English  4-Element  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 

September,  1924 

— How  Careful  Mounting  Will  Improve  Reception. 

— One  Tuning  Control  for  Hair's  Breadth  Selectivity. 

— 'Four  Pages  of  Real  Blueprints  of  a  New  Baby  Heterodyne 

and   an  Aperiodic   Variometer  Set. 
— 'Data  Sheets. 
October,  1924 

— An  Easily  Made  Super-Het. 
— Two  Radio  and  Two  Audio  for  Clear  Tone. 
— A  Simple  Regenerative  Set. 

—The  Ultradyne  for  Real  DX.  '-- 

— Real  Blueprints  of    a    3-Tube    Neutrodyne    and    a    Midget 

Reflex  Set. 
November,  1924 
— Blueprints    of    a    Single    Tube    Loop    Set    and    a    Capacity 

Feedback    Receiver. 
— A  3-Tube  Low  Loss  Regenerator. 
— Mastering  the  3-Circuit  Tuner. 
December,  1924 

— Blueprints  of  a  New  8-Tube  Super-Heterodyne. 
— How  to  Make  a  Receiver  that  Minimizes  Static. 
—A  Trans-Atlantic  DX  Receiver. 
— How  to  Make  a  Home  Made  Battery  Charger  and  a  Loud 

Speaker  at  a  Small  Cost. 
January,  1925 
— A  Reflexed  Neutrodyne 
—A  Six  Tube  Super-Het. 
—An  Efficient  Portable  Set. 


— A  Tuned  Plate  Regenerator. 
— Making  a  Station-Finder. 
February,  1925 
— A  Sure  Shot  Super-Het. 
— A  Three  Circuit  Regenerator. 
— A  Real,  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex  *J-       '. 

March,  1925  3? 

— A  Permanent  Super-Het. 
— A  5-Tube  R.  F.  Receiver. 
— How  to  Wind  Low  Loss  Coils. 
— A  Short  Wave  Receiver 

— Blue  Prints  of  a  Two-Tube  Ultra  Audioo  and  a  Re- 
generative Reflex. 
April.  1925 

—A  3-Tube  Portable  Set 
— "B"  Voltage  from  the  A.  C.  Socket 
— An  Amplifier  for  the  3-Circuit  Tuner 
— -Blueprints  of  a  Five-Tube  Radio  Frequency  Receiver 
May.  1925 

— A  "Quiet"  Regenerator. 
— A  Power  Supply  Receiver. 
— How  to  Make  a  Tube-Tester. 

— A  Unique  Super-Het  and  an  Improved  Reinarti. 
—A     Six    Tube    Portable    Receiver    Illustrated    with    Blu 

June,  1925 

— Reducing  Static  Disturbances 

— A  Seven-Tube  Super-Heterodyne 

—The  Double  Grid  Tube  in  Ordinary  Sets 

— -Browning- Drake  Receiver 

— Overcoming  Oscillations  in  the  Roberta  Receiver 

— An  Ideal  Set  in  Practical  Form 

— Soldering  Secrets 


500  N.  DEARBORN  ST.,  CHICAGO 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


103 


CLASSIFIED  ADVERTISEMENTS 

If  you  have  anything  to  buy  or  sell,  don't  overlook  the  value  of  RADIO  AGE'S  classified 
advertisements.    Many  such  messages  have  paved  the  way  to  independent  incomes. 

The  classified  advertising  rates  are  but  ten  cents  per  word  for  a  single  insertion.  Liberal 
discounts  are  allowed  on  three,  six  and  twelve-time  insertions,  of  five,  fifteen  and  thirty  per  cent 
respectively.  Unless  placed  through  an  accredited  advertising  agency,  cash  should  accompany 
all  orders.  Name  and  address  must  be  included  at  foregoing  rates  and  no  advertisement  of  less 
than  ten  words  will  be  accepted. 

All  classified  ads  for  the  September  issue  must  be  sent  in  by  August  1 . 


AGENTS  WANTED 


FORDS.  60  miles  on  one  gallon  of  Gas.  It  has  been 
proven  such  mileage  can  be  made.  AIRLOCK  guar- 
antees to  increase  gas  mileage;  also  prevents  radiator 
boiling  in  summer  or  freezing  in  winter.  Cools,  Fuels, 
Decarbonizes  the  Ford  motor.  Splendid  territory 
open.  AIRLOCK  PRODUCTS,  Box  703G,  Willow  Street, 
Long  Beach,  Calif. 


RADIO— Join  our  sales  organization  and  make  big 
money.  We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers. Widener  of  Kansas  City  makes  $150.00 
weekly.  You  can  do  as  well  or  better.  Write  today 
for  catalog,  and  discounts.  Name  your  county.  Wave- 
land  Radio  Company,  Div.  52,  1027  No.  State  St.,  Chi- 
cago,  111. 

MANUFACTURER'S  AGENT  calling  on  Radio-Elec- 
trical Jobbers,  Chicago  and  vicinity,  has  opening  for  3 
additional  lines  carrying  volume  business,  as  we  cater 
to  large  jobbers.  Edelstein,  1804  McCormick  Bid., 
Chicago. 


AGENTS— WRITE  FOR  FREE  SAMPLES  Sell  Madison 
■■Better-Made"  Shirts  for  large  manufacturer  direct  to 
wearer.  No  capital  or  experience  required.  Many 
earn  $100  weekly  end  bonus.  MADISON  MFGRS..  501 
Broadway,  New  York. 


90c  an  hour  to  advertise  and  distribute  samples  to  con- 
sumer. Write  quick  for  territory  and  particulars. 
American  Products  Co.,  2130  American  Building.  Cin- 
cinnati, Ohio. 


Man  wanted  for  this  territory  to  sell  wonderful 
value  men's,  women's.  Children's  shoes  direct,  sav- 
ing consumer  over  40%.  Experience  unnecessary. 
Samples  supplied.  Big  weekly  permanent  income. 
Write  today  Tanners  Mfg.  Co.,  1334C.  St.,  Boston,  Mass. 


'B"    BATTERIES 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parts  and  plans — complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake,  Chicago. 


BATTERIES  FOR  SALE— Four  24-volt  "Main"  Storage 
"B"  Batteries,  never  used,  shipped  and  ready  to  wire 
for  $38.00.  First  order  gets  the  batteries.  Address 
Box  B,  Radio  Age,  500  N.  Dearborn  St.,  Chicago.  111. 


BUSINESS    OPPORTUNITY 


MR.  MANUFACTURER:  Would  you  be  interested  in 
a  national  advertising  campaign  to  reach  more  than 
two  million  prospective  buyers  of  quality  radio  products 
— -each  week?  Do  you  want  to  establish  agencies  in 
new  territory  and  create  national  interest  in  your 
product — at  a  very  conservative  cost?  It  can  be  done. 
Let  us  explain  our  system  without  obligation  to  you. 
Drop  a  card  to  Radiograph  Laboratories,  1234  Ros 
Ave.,  Chicago,  III.,  Box  6. 


CRYSTALS 


TESTED  GALENA  CRYSTALS,  50c  pound  bulk, 
kett.  Geologist.  Joplin,  Mo. 


HELP  WANTED 


RADIO  SALESMEN  and  SET  BUILDERS— We  n..d 
you  and  you  need  us.  If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  price,  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  III. 


MEN  wanting  forest  ranger,  railway  clerk  and  other 
government  positions,  write  for  free  particulars  of 
exams.      Mokane,    Dept.   B-33,    Denver,   Colo. 


Classified  ad.  copy  for  the  Sep- 
tember RADIO  AGE  must  be  sent 
in  by  August  1,  1925. 


INVENTIONS 


NEW  IDEAS  WANTED— Well  known  Radio  Manufac- 
turer whose  products  are  nationally  advertised  and  sold 
everywhere  wants  new  Radio  device  to  sell.  Will  pay 
outright  or  royalty  for  idea  or  invention  which  is  really 
new  and  saleable.  Address:  Mr.  R.  F.  Devine,  Room 
1101.  116  West  32nd  St..  New  York.  N.  Y. 


MAGAZINES 


DREAMS.  A  magazine  for  all  who  dream.  If  you 
are  interested  in  the  subjects  of  science,  sex,  psychology, 
health,  love  and  romance,  you  cannot  afford  to  be  with- 
out this  magazine.  Three  dollars  will  bring  this  most 
fascinating  monthly  publication  to  your  home  for 
one  year.  M.  B.  Smith  Publishing  Co.,  508  N.  Dearborn 
St.,  Chicago,  III. 


MANUFACTURING  FACILITIES 


AN  OLD  AND  WELL  ESTABLISHED  MANUFACTUR- 
ING COMPANY  IN  THE  MIDDLE  WEST  WITH  LARGE 
WELL  EQUIPPED  PLANTS  AND  UNUSUAL  FINAN- 
CIAL RESOURCES.  DESIRINC  TO  ENTER  THE  RADIO 
FIELD  WILL  CONSIDER  THE  MANUFACTURE  AND 
SALE  OF  RADIO  SETS  OR  DEVICES  OF  OUTSTAND- 
ING AND  UNUSUAL  MERIT  ON  A  ROYALTY  BASIS. 
ADDRESS  BOX  1A,   RADIO  AGE. 


PATENTS 


FOR  SALE:  U.  S.  and  Canadian  Patent  on  an  Attach- 
ment for  Phonographs;  is  the  most  beautiful  inven- 
tion of  the  age.     Address  Chas.  F.  Smith,  Huff,  N.  Dak. 


PERSONAL 


LONELY  HEARTS 
new  friends  in  ou 
Jacksonville,  Florh 


Exchange  letters;  make  interesting 
jolly  club.  Eva  Moore,  Box  908, 
,    Enclose  stamp. 


look!      You    Radio    Bugs!     Join 

Club.       Entirely    new.       Broad 

exchange    ideas.       Membership    open    to    LADY    BUGS 

also.     Dime  stamp  brings  pamphlet  and  Radio  Novelty 

Cards.     Radio  Rose,  Box  662,  Cleveland,  Ohio. 


PRINTING 


RADIO 


A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  III. 


Standard  soderless  radio  Jacks.  Binding  post  attach* 
ments.  Double  circuit.  One  dollar  bill.  Postpaid. 
Clinton   Seward,  Jr.,  New  Paltz,   New  York,  N.    Y. 


15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.  Every  item  guaranteed.  Tell  us  your  needs. 
IMPERIAL  RADIO  COMPANY,  Delaware,  Ohio. 


RADIO  SETS.      Our  prices  save  you  money.      Lists  free. 
The  Radio  Shoppe,  Box  645,  East  Liverpool,  Ohio. 


Radio   Specialty 


NOTICE  TO  READERS! 

Up  to  and  including  August  15,  1925, 
the  August  number  of  RADIO  AGE 
will  sell  for  the  customary  price  of  25c 
per  copy,  but  after  that  date  the  price 
will  be  50c  per  copy.  If  you  wish  for 
additional  copies,  or  know  of  friends 
who  might  want  this  August  issue, 
BUY   NOW   before  the  price  goes  up! 


RADIO  CIRCUITS 


SPECIAL  FOR  JULY 
The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne,  fullv 
illustrated,  and  RADIO  AGE,  for  12.50.     Price  of  Book- 
let alone  is  50c.      Send  check,  currency  or  money  order 
to  RADIO  AGE,  500  N.  Dearborn  Street,  Chicago. 


RADIO  DEALERS 


DEALERS— Write  to 
Radio  Merchandise. 
Dept.  D,  1830  Wilson 


illustrated  catalog  of  reliable 
ssiter-Manning  Corporation, 
,  Chicago.  III. 


RADIO  SUPPLIES 


Ten  per  cent  discount  on  all  standard  radio  parts, 
from  condensers  to  transformers  to  tubes,  etc.  Send 
for  our  latest  price  list,  with  special  bargains  on  Statle- 
eliminators,  portable  loud  speakers,  Radiotrons,  Ger- 
man silver  wire,  etc.  RADIOGRAPH  LABORATORIES. 
1234  Rosemont  Ave.,  Dept.  4,  Chicago,  III. 


STAMPS  AND  COINS 


158  Genuine  Foreign  Stamps.  Mexico  War  Issues, 
Venezuela,  Salvador  and  India  Service.  Guatemala, 
China,  etc.,  only  5c.  Finest  approval  sheets,  50  to 
60  per  cent.  Agents  Wanted.  Big  72-p.  Lists  Free. 
We  Buy  Stamps.  Established  20  Years.  Hussman 
Stamp  Co.,  Dept.  152,  St.  Louis,  Mo. 

STAMPS,  50  varieties,  Africa,  Brazil,  Peru,  Cuba, 
Mexico,  etc.,  10c.  50  different  U.  S-.  25c;  1,000  mixed, 
40c;  1,000  hinges,  10c.  List  free.  C.  Stegman,  5950 
Cote  Brilliante,  St.  Louis,  Missouri. 


VOCATIONS 


WANTED 


WANTED— To  complete  my  set  RADIO  AGE  need 
August,  September,  October,  November,  1923,  issues, 
bound  or  unbound.  Advise  price.  Lloyd  C.  Hennint, 
Hellbrook,  Arizona. 


WIRELESS 


WANT  TO  MEMORIZE  THE  WIRELESS  CODE?  The 
Coryden  Snyder  Code  Method.  Patented,  is  quickest. 
Send  50c  coin,  stamps  or  M.  O.  to  C.  G.  Snyder.  1423 
Elmdate  Ave..  Chicago,  III. 


TELEGRAPH  Y— Morse  and  Wireless— taught  at  home 
in  half  usual  time  and  at  trilling  cost.  Omnigraph 
Automatic  Transmitter  will  send,  on  Sounder  or  Buz- 
zer, unlimited  messages,  any  speed,  just  as  expert 
operator  would.  Adopted  by  U.  S.  Govt,  and  used  by 
leading  Universities,  Colleges,  Technical  and  Telegraph 
Schools  throughout  U.  S.  Catalog  free.  Omnigraph 
Mfg.  Co.,  13  F  Hudson  St.,  New  York. 


WRITERS 


NEW  WRITERS  WANTED— Articles,  stories,  poems, 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No.  bunk.)  NOT  A  CORRE- 
SPONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
azines. Send  self  addressed  envelope  for  list  of  100 
subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Loa 
Angeles.  Calif. 


WRITERS— Cash  in  on  your  knowledge  of  radio  by 
writing  for  Radio  Magaxines  and  Newspaper  Supple- 
ments. Write  up  your  radio  experiences,  your  new 
hook-up,  your  knowledge  of  broadcasting  stations  and 
artists.  Experienced  authors  will  correct  and  improve 
your  manuscripts— make  them  typically  professional 
work.  FREE  Criticism  and  Advisory  Service  until  your 
manuscript  is  soldi  ALL  Magazines  and  Papers  de- 
manding fiction  and  articles  dealing  with  radio.  Here 
is  YOUR  OPPORTUNITY  to  profit!  Send  for  FREE 
booklet,  "How  You  Can  Sell  Your  Manuscripts." 
Willis  Arnold  and  Associates,  210  East  Ohio  St. 
Chicago,  III. 

Make  big  money  writing  Movie  Plays.  Circulars  free. 
W.    C.    Krug,    Ashton,    Illinois. 


Have  you  ordered  your 
September  Radio  Age  ? 


•¥-     Tested  and  Approved  by  RADIO  AGE     * 


104 


RADIO  AGE  for  August,  1925 


The  Magazine  of  the  Hour 


POLK'S  REFERENCE  BOOK 

FOR    DIRECT   MAIL    ADVERTISERS 

Shows  how  to  increase  your  business  by 
the  use  of  Direct  Mail  Advertising,  60  pages 
full  of  vital  business  facts  and  figures.  Who, 
where  and  how  many  prospects  you  have. 
Over  8,000  lines  of  business  covered. 
Write   for  your  FREE  copy. 

R.  L.  POLK  &  CO.,  Detroit,  Mich. 

5S9  POLK    DIRECTORY    BUILDING 

Branches    In    principal    cities   of   U.    S. 


Storage  "B"  Battery 

"vlHl    Lasts  Indefinitely— Pays  for  Itself 

Economy  and  performance  unheard  of  before.    Recharged 
at  a  negligible  cost.    Approved  and  listed  as  Standard  by 

eadlng  Kadi<->  Authorities,  including  Pop.  Radio  Laboratories,  Pop. 
Sci.  Inst.  Standards,  R'.lio  News  Lab  Lefax,  Inc.,  and  other  Im 
porrant  institutions.  Equipped  with  Solid  Rubber  Case,  an  insur- 
ance against  acid  and  leakage.  Extra  heavy  glass  jars.  Hcavs. 
rugged  platea.     Order  yours  today! 

SEND  NO  MONEY  JSkSpSU"^ %Sl  Sg"5S 

order  la  received.  Extra  Offer:  4  batteries  in  series  (96  volta) ,  $12.75. 
Pay  expreBsman  after  examining  batterleB.  5  per  cent  discount  for 
cash  with  order.     Mail  your  order  now! 

WORLD  BATTERY  COMPANY 
1219  So.  Wabash  Ave.,      Dept.  81,       Chicago,  IU. 

Makers  of  the  Famous  World  Radio  "A"  Storage  Battery 

Prices:    6-volt,  100  Amp.  $12.::,-;    l?n  Amp.  Sli.25;  HO  Amp.  $15.00. 

All  equipi" ■■(■/  t'-itfi  Solid  Rubber  Case, 


World 


STORAGE  BATTERIES 

lroKA*WfcAF<W6NJWJ5>KHj7KS0^KFAFJW3yyKgal 


DUIIE  RADIO  CONSOLE 

I\llUL&   MFG.C0.562VEDDERST. 

CHICAGO.    WRITE    FOR    CIRCULAR 


Radio  Age  Institute 

Manufacturers'  Testing  Service 

X/TEMBERS  of  the  staff  of  RADIO  AGE  will  be  pleased  to  test  devices 
J-VA  and  materials  for  radio  manufacturers  with  the  object  of  deter- 
mining their  efficiency  and  worth.  All  apparatus  which  meets  with 
the  approval  of  various  tests  imposed  by  members  of  the  technical 
staff  of  RADIO  AGE  will  be  awarded  our  endorsement,  and  the  In- 
stitute seal  will  be  furnished  free  of  charge.  Materials  for  testing 
should  be  sent  to 

RADIO  AGE  INSTITUTE 

504  N.  Dearborn  Street,  Chicago,  111. 


DEVICES 

displaying  this  seal 
have  been  tested 
and  approved  by 
the  RADIO  AGE 
INSTITUTE. 

Apparatus  illus- 
trated and  de- 
scribed below  has 
successfully  passed 
our  tests  for  Aug- 
ust,  1925. 


conven- 
tional lugs 
for  making  connections.  A  cut-away 
section  shows  the  plates  made  of  thin 
brass  leaves  with  ample  dielectric,  the 
whole  mounted  securely  in  a  metal 
housing.  The  capacity  is  stamped  on 
the  back  of  the  housing.  Submitted 
by  the  A.  E.  Hill  Manufacturing  Co., 
of  Atlanta,  Ga.  Tested  and  approved 
by   the   RADIO   AGE    Institute. 


Test  No.  80. 
A  compen- 
sated multiple 
variable  condenser 
which  the  manu- 
facturers claim  to  be  the  only  practical 
single  dial  control  unit  on  the  market. 
Submitted  by  the  United  Scientific 
Laboratories,  Inc.,  80  Fourth  Avenue, 
New  York  City.  It  can  be  built  into 
any  tuned  radio  frequency  circuit;  is 
compact  and  space  saving  and  reduces 
panel  requirements.  This  new  multiple 
is  a  straight-line,  low-loss  condenser 
making  the  sharpest  tuning,  quick  and 
easy.  The  manufacturers  claim  that 
dozens  of  stations  can  be  brought  in 
instantly.  Capacity  .00035  mfd.  per 
unit.     Tested  and  approved  by  RADIO 

AGE     Institute. 

Test  No.  81. 
Submitted  by  the 
Anylite  Electric 
Co  .  ,  at  Ft . 
Wayne,  Ind.  The 
sample  consists 
of  an  audio  fre- 
quency trans- 
former, well  built 
and  shielded, 
designed  for  use 
in  any  audio  am- 
plifier where 
clearness  of 
speech  and  volume  is  desired.  Tested 
and  approved  by  RADIO  AGE  Institute. 


MARSHALL  Ba^eFcreei?eresnC7 

Embodying  a  marvelous  New 
*         Non-Oscillating  Principle 
Sold  Direct  on  Free  Trial  and  Easy  Terms 
Write  for  catalog  and  Special  Offer 

Marshall  Radio  Products,  Inc. 

D e pi. B -589  Marshall  Blvd.  &  1 9th St.,  Chicago 


Test  No.  82. 
SILVER  "TWO- 
TENS"  *  and 
"TWO-ELEV- 
ENS." Long  wave 
transformers.  New 
style  B  a  k  e  1  i  t  e 
Cases,  replacing 
the  old  type  alu- 
minum case,  and 
far  more  efficient.  Supplied  in  sets  of 
2  or  3  21.0's  (iron  core  interstage  and 
one  211,  (filter  for  input  or  out-put) 
with  identical  peaks  and  separate  curves. 
The  feature  of  these  transformers  lies  in  the  fact 
that  the  makers  plot  the  curve  in  their  own  labora- 
tory and  record  them  directly  on  a  tag  attached  to 
each  transformer  before  it  is  placed  on  sale.  Tests 
to  determine  the  accuracy  of  these  charted  and 
matched  transformers  were  conducted  in  this  maga- 
zine's laboratory  and  in  every  instance  the  tag  at- 
tached to  each  transformer  was  found  to  have  the 
correct  curve.  Manufactured  and  submitted  by 
Silver-Marshall,  Inc.,  105  S.  Wabash  Ave.,  Chicago. 
Satisfactorily  passed  the  tests  and  requirements  of 
the  RADIO  AGE  Institute. 

TestNo.83 
submitted 
by  the 
Electrad, 
Inc.,  428 
Broad- 
way, New 
York. 
Sample 
consists 
of  a  grid  condenser  type  G-S  equipped 
with  punched  connecting  lugs  by  means 
of  which  the  condenser  may  be  mounted 
directly  to  the  socket.  There  are  two 
prongs  for  the  use  of  a  cartridge  resistance  of  a  grid 
leak.  The  capacity  of  each  condenser  is  stamped 
on  the  prongs.  Tested  and  approved  by  the  RADIO 
AGE  Institute. 


Test  No.  84.  Sample  submitted  by 
the  Walbert  Mfg.  Co.,  925  Wrightwood 
Ave ,  Chicago,  111.  This  socket  of 
bakelite  with  a  safety  top  rim  has  both 
side  and  bottom  contacts  for  the  prongs 
of  a  vacuum  tube.  With  both  types  of  friction  con- 
tact there  should  be  no  difficulty  with  loose  con- 
nections. Tested  and  approved  by  RADIO  AGE 
Institute. 

Test  No.  85. 
Submitted  by 
Dongan  Elec- 
tric Manufac- 
,t  u  r  i  n  g  Co., 
2983  Franklin 
St.,  Detroit, 
Mich.  This 
unit  is  designed  for  delivery  from  110 
volts,  a.c.  of  the  necessary  voltage  for 
the  new  McCullough  a.  c.  tubes.  Equipped 
with  lever  switch  for  various  voltage 
taps.  Tested  and  approved  by  RADIO 
AGE    Institute. 


#     Tested  and  Approved  by  RADIO  AGE     * 


Mr.  Manufacturer 

Would  you  write  100 
letters  to  100  people 
to  reach  just  two  men  ? 

Then,  before  you  invest  your  advertising  dollars — THINK! 


This  Association 
is  comprised  of 
the  leading  Ra- 
dio Magazines. 


An  analysis  shows  that  publications  of  general  circulation, 
newspapers  and  magazines,  devote  less  than  2%  of  their 
reading  columns  to  Radio — proving  that  in  the  opinion  of 
their  own  Editors  less  than  2%  of  their  readers  are  inter- 
ested in  Radio.  In  fact,  many  general  publications  carry  no 
Radio  editorial  matter.  Therefore — 98%  of  your  investment 
is  lost! 

On  the  contrary,  the  Radio  magazine  offers  100%  Radio 
editorial — attracts  100%  potential  buyers. 

Spend  your  advertising  appropriation  in  Radio  Magazines. 
Be  sure  of  the  greatest  possible  return  on  your  advertising 
dollar, 

Radio  Magazine  Publishers'  Association,  Inc. 

RADIO  AGE  is  a  member  of  the  Radio  Magazine  Publishers  Association,  Inc. 


iHiniMiiiim^iHinniinnTTHirniiiiiTirmirT 


* 


LONG    DISTANCE 

TRADE     MARK     REG. 


RADIO 


Arctic  Explorers  Stake  Their  Lives 
on  Zenith  Radio  — 


Costs  More 

But  Does  More 


It  is  one  thing  to  select  a  radio  set  for  pleasure  only  —  it  is 
quite  another  to  select  a  set  which  may  be  called  upon  most 
unexpectedly  to  save  your  life. 

Alone  in  the  Arctic — cut  off  from  the  nearest  rescue  post  by 
hundreds  of  miles  of  ice  and  open  water — men  cannot  run  to 
the  nearest  radio  shop  for  repairs.  If  transportation  fails, 
and  radio  does  not  work,  they  are  in  the  gravest  peril. 

This  summer — across  the  million  square  miles  of  unexplored 
territory  stretching  between  Alaska  and  the  North  Pole  — 
MacMillan  and  his  party  of  explorers  will  fly  in  three  great 
navy  planes.  Each  of  these  cruising  airplanes  is  equipped 
with  Zenith  radio,  as  are  the  Bowdoin  and  the  Peary,  which 
will  locate  at  Etah  as  their  base.  Between  ships  and  airplanes 
messages  will  be  sent  and  received. 

When  Arctic  explorers  of  MacMillan' s  calibre  stake  their 
lives — repeatedly  —  on  Zenith  performance,  one  reason  only 
can  explain  their  choice — Zenith  has  proved  to  be  the  best 
obtainable,  at  any  price. 

Call  this  evening  at  your  nearest  Zenith  dealer  and  let  him 
prove  it  to  you  by  a  demonstration. 

ZENITH  RADIO  CORPORATION 

310  South  Michigan  Avenue,  Chicago 


THE  complete  Zenith  lineranges 
in  price  from  $100  to  $475. 
With  either  Zenith  3R  or  Zenith 
4R,  satisfactory  reception  over  dis- 
tances of  2,000  to  3,000  miles  is 
readily  accomplished,  using  any 
ordinary  loud  speaker.  Models 
3R  and  4R  licensed  under  Arm- 
strong U.  S.  Patent  No.  1.113,149. 
They  are  NON-RADIATING. 

Zenith  4R  -  $100 
Zenith  3R  -  $  1 75 

The  new  Super-Zenith  is  a  six-tube 
set  with  a  new,  unique,  and  really 
different  patented  circuit,  con- 
trolled exclusively  by  the  Zenith 
Radio  Corporation.  It  is  NOT 
regenerative. 


SUPER-ZENITH  VII— Six  tubes-2  stages  tuned 
frequency  amplification— detector  and  3  stages  audio 
frequency  amplification.  Installed  in  a  beautifully 
finished  cabinet  of  solid  mahogany—  44?e  inches  long, 
16%  inches  wide,  10?a  inches  high.  Compartments  at 
either  end  for  dry  batteries.  Price  «T»r>y*i-k 
(exclusive  of  tubes  and  batteries) 2p^54'd 


SUPER-ZENITH  VHI-Same  as  VII  except-con- 
sole  type.  Price  (exclusive  of  tubes  and  -t>  «->>-»  y-v 
batteries) 2p*doCJ 


SUPER-ZENITH  IX— Console  model  with  addi- 
tional  compartments  containing  built-in  Zenith  loud 
speaker  and  generous  storage  battery  space. 
Price  (exclusive  of  tubes  and  batter-  --»  «->  t^  E? 
ies) »p355 

SUPER-ZENITH  X— Contains  built-in,  patented, 
Super-Zenith  Duo-Loud  Speakers  (harmonically 
synchronized  twin  speakers  and  horns),  designed  to 


reproduce  both  high  and  low  pitch  tones  otherwise 
impossible  with  single-unit  speakers.  «*»  jy  i^f* 
Price  (exclusive  of  tubes  and  batteries)    ^**"  /  O 

All  Prices  F.  O.  B.  Factory 


Zenith  Radio  Corporation 

Dept.  C-8 
310  S.  Michigan  Avenue,  Chicago,  Illinois 

Gentlemen: 

Please  send  me  illustrated  literature  about 
Zenith  Radio. 


Name 

Address. 


*     Tested  and  Approved  by  RADIO   AGE     * 


Blueprint  Section  Every  Month 


<^Ma<Sa3irve  of  the  Hour 


SEPTEMBER 
1925 

25 CENTS 


MTft  vniip  RPriArwAsr  fax/aditfc 


DEE 


3EE 


USE 


3EC 


SEE 


3EE 


SEE 


SEE 


SEE 


SEE 


SEE 


A  New  B-T  Achievement 


Where  correct  design  is  under- 
stood, and  quality  appreciated 
you  will  always  find  the  highest 
praise  for  B-T  products. 

The  Counterphase  Six  reaches 
new  heights  and  sets  new  stand- 
ards. 

The  accomplishment  of  a  long- 
deferred  hope, — putting  the  6th 
tube  where  it  belongs, — as  a  third 
stage  of  Tuned  Radio  Frequency 
gives  long  distance  operation  with 
only  a  short  indoor  antenna. 
And  but  two  tuning  dials  are  re- 
quired. Anything  less  would  be 
uninteresting!       Simply  turning 


one  knob  gives  every  variation 
from  utmost  volume  to  the  finest 
shade  of  sensitivity. 

A  wiring  cable  furnished  with 
each  "kit11  provides  a  new  idea 
in  making  construction  easy. 

The  "Counterphase11  is  manu- 
factured under  exclusive  B-T 
patents  and  provides  oscillation 
control  over  the  complete  broad- 
cast range. 

B-T  reputation  for  unequalled 
inductance  design  is  world-wide. 
The  Torostyle  is  another  triumph 
of  outstanding  efficiency. 


Don't  Buy   Straight   Line   Frequency   Condensers 


until  you  have  read  our  analysis  and 
seen  our  product.  We  believe  many 
persons  expect  more  than  is  possible. 
We  build  both  kinds — our  designs  are 
original,  and  quality  unequalled.  This 
subject  with  many  others,  including 
the  "Counterphase,"  "bridge  cir- 
cuits," etc.,  are  included  in  "Better 
Tuning"  8th  edition,  published  Aug. 
20th. 


Send  circulars  on  your  Audio  Transformer, 
Universal  Socket,  Tuning  Control,  High  Resist- 
ances, '■'Torostyle1'  Transformers  and  all  B-T 
products. 


□ 

Send    "Better    Tuning1 

8th    Ed. 

10c    enclosed 

□ 

Send   "Better  Tuning11 

one  year. 

50c  enclosed 

532  S.  Canal  St. 


Chicago,  111. 


# 


=ini im  ini,  inr= 


BEE 


ini  inp 


SEE 


=if?i  -ini  ini  iPir: 


Bremer -Tully  Mfg.  Co.     I 


_i 


¥     Tested  and  Approved  by  RADIO   AGE     # 


RADIO  AGE  for  September,  1925  The  Magazine  of  the  Hour 


SUCCESSFUL 
RADIO  ADVERTISING 


<& 


HE  difference  which  makes  your  radio  product 
better  than  another  is  technical.  Yet  an  ad- 
vertisement which  confines  itself  to  statement  of 
the  technicality  cannot  yield  sales.  Nor  can  an  ad- 
vertisement which  ignores  the  technical  difference. 


The  radio  advertising  which  we  prepare  is  success- 
ful for  two  reasons: 

We  know  Radio,  and  therefore  understand 
our  clients'  radio  products. 

We  know  Advertising,  and  consequently 
are  able  to  interpret  into  impressionable 
language,  the  technical  individualities  of 
the  radio  products  about  which  we  write. 

If  you  are  interested  in  finding  out  how  much 
more  effective  your  advertising  can  be  made  when 
it  is  prepared  by  an  advertising  agency  which  is  able 
to  appreciate  your  product  technically,  we  invite 
your  correspondence. 

This   advertisement  is  directed  to 
reputable,  established  manufacturers 

% 


ESTABLISHED  1913 


646  North  Michigan  Boulevard,  Chicago 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Establish^  March,  Hit 

WITH  WHICH  IS  COMBINED  RADIO  TOPICS 


Volume  4 


September,  1925 


Number  9 


CONTENTS 

Cover  Design  by  Fred  I.  Good 
Radio  Editorials 4 

Thirty-one  Ways  to  Prevent  Self-Oscillations 7 

By  Roscoe  Bundy 

Solving  Wavelength  Problems 13 

By  E.  E.  Griffin 

Down  to  Lower  Waves... 15 

By  Armstrong  Perry 

Tuning  Efficiency  with  Two  Controls 17 

By  Brainard   Foote 

Theory  of  Transmission  and  Reception 19 

By  Frank   D.   Pearne 

Radio  Movies  at  Last!.. 21 

By  S.  R.  Winters 

How  to  Measure  Radio  Distance 23 

RADIO  AGE  "What  the  Broadcasters  are  Doing" 

Feature  Section 24-32 

RADIO  AGE  Blueprint  Section 33-40 

Ideal  Audio  Amplifier  Circuits 1 ..33-40 

By  John   B.   Rathbun 

Pickups  and  Hookups. 43 

With  the  Radio  Manufacturers .....52 

How  to  Build  a  5-Tube  Toroid  Set 54 

Standard  Radio  Receivers.... 56-57-58 

Corrected  List  of   Broadcasting  Stations 66-68-70 


Radio  Age  is  published  monthly  by  RADIO  AGE,  Inc. 
Member:     Audit  Bureau  of  Circulations. 


Publication    Office,    Mount    Morris,    111. 

Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500   N.  Dearborn   Street,    Chicago,    111. 


Frederick  A.  Smith,  Editor 
Frank  D.  Pearne,  Technical  Editor 
M.  B.  Smith,  Business  Manager 


Advertising  Director 
HARRY  A.  ACKERBURG 

500  N.  Dearborn  St.,  Chicago,  III. 


Eastern  Representative 
DAVIDSON   &   HEVEY,    17  West  42nd  St.,  New  York  City 


Pacific  Coast  Representative 

V.   M.   DEPUTY  &  ASSOCIATES,    515  F.   W.  Braun   Bldg.; 

Los  Angeles,  Cal. 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 

preceding  date  of  issue 

Vol.  4,  No.  9.   Issued  monthly.   Subscription  price  $2.50  a  year.   September,  1925. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris.  Illinois,  under  the 

Act  of  March  3.  1879. 


Ccmright,  ISts.  bv  RADIO  AGE.  In*. 


A  Chat  With 
the  Editor 


OUR  readers  gave  us  a  surprise 
last  month.  They  bought 
the  August  issue  in  such 
numbers  that  the  stock  held  by 
dealers  in  many  of  the  larger  cities 
was  practically  exhausted  a  few 
days  after  the  big  blue  print  num- 
ber went  on  sale. 

It  was  a  remarkable  evidence  of 
technical  radio  interest  at  a  season 
of  the  year  when  that  interest  is 
presumed  to  be  at  its  lowest 
point.  Newsdealers,  realizing 
that  the  early  sales  meant  dis- 
appointment to  those  who  might 
be  a  bit  late  in  seeking  their  August 
number,  wired,  telephoned  and 
wrote  to  our  circulation  office, 
asking  for  additional  copies.  Some 
of  these  orders  were  filled  but  the 
majority  of  them  were  not.  It 
was  too  late  to  put  the  August 
forms  back  on  the  presses  for  an 
additional  run,  as  that  would  have 
interfered  with  the  preparation 
of  the  September  book. 

Therefore  this  magazine  occu- 
pied the  interesting  and  perhaps 
unique  position  of  being  one  radio 
enterprise  that  could  not  fill  its 
orders  in  the  midst  of  the  dog  days. 

We  hereby  express  our  regret, 
to  the  newsdealers  whom  we  were 
forced  to  disappoint.  At  the  same 
time  we  believe  it  to  be  a  good 
opportunity  to  say  to  our  readers 
once  more  that  the  safest  way  to 
be  sure  of  getting  RADIO  AGE  is 
to  subscribe  for  the  magazine  and 
have  it  delivered  to  your  door 
each    month. 

This  is  not  one  of  those  left- 
handed  advertisements.  It  is 
merely  a  statement  of  fact  and, 
after  last  month's  experience,  we 
are  confident  it  will  carry  con- 
viction . 

There  will  be  a  few  unsold  copies 
of  the  August  issue  returned  from 
remote  points.  We  have  arranged 
to  put  them  aside  for  the  dis- 
appointed ones  who  may  obtain 
them  at  the  special  price  of  50 
cents   each.      Stamps   will   do. 

^^^^^ 

Editor  Radio  Age. 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


No.  486  Evcready  Layerbilt 
"B"  Battery.  45  volts.  Length, 
8  3/16  inches.  Width,  4  7/16 
inches.  Height,  7  3/16  inches. 
Weight,  14*4  pounds.  Price, 
$5.50. 


It's  all  battery.  With  every  cubic 
inch  packed  to  capacity,  it  con- 
tains about  30  per  cent  more  electricity- 
producing  material.  All  chance  of  loose 
or  broken  connections  avoided  by  contact 
of  full  area  of  carbon  plate  against  zinc 
plate.    The  scientifically  correct  construction. 


* 


The  greatest  improvement 
ever  made  in  "B"  Batteries 


Absolutely  new  in  construction — per- 
fected through  years  of  research,  the 
new  Eveready  Layerbilt  "B"  Battery 
is  as  superior  to  the  old  type  "B" 
Battery  as  a  tube  set  is  to  a  crystal. 

Heretofore,  all  dry  "B"  Batteries 
have  been  made  up  of  cylindrical  cells 
— no  one  knew  how  to  make  them  any 
other  way.  The  new  Eveready  Layer- 
bilt is  made  of  flat  layers  of  current- 
producing  elements  compressed  one 
against  another,  so  that  every  cubic 
inch  inside  the  battery  case  is  com- 
pletely filled  with  electricity-producing 
material.  Layer-building  heightens  effi- 
ciency by  increasing  the  area  of  zinc 
plate  and  the  quantity  of  active  chemi- 
cals to  which  the  plate  is  exposed. 

After  the  most  rigid  laboratory  tests, 
more  than  30,000  of  these  new  Ever- 
eady Layerbilt  "B"  Batteries  were 
manufactured  and  tested  by  use  under 
actual  home-receiving  conditions.  These 
tests  proved  that  this  new  battery  is 
far  superior  to  the  famous  Eveready 
Heavy-duty  Battery  No.  770,  which 
up  to  now  we  have  ranked  as  the 
longest  lived  "B"  Battery  obtainable. 

On  4-tube  sets,  16  mil  drain,  it  lasts  35%  longer. 

On  5-tube  sets,  20  mil  drain,  it  lasts  38%  longer. 

On  6-tube  sets,  24  mil  drain,  it  lasts  41%  longer. 

On  8-tube  sets,  30  mil  drain,  it  lasts  52%  longer. 


The  new  Layerbilt  principle  is  such 
an  enormous  stride  forward  in  radio 
battery  economy  that  we  will  bring  out 
new  sizes  and  numbers  in  this  Layer- 
bilt form  as  fast  as  new  machinery  is 
installed.  For  the  present,  only  the 
extra-large  45-volt  size  will  be  available. 

Buy  this  new  Eveready  Layerbilt 
No.  486  for  heavy  drain  service.  It 
far  exceeds  the  performance  for  which 
Eveready  Radio  Batteries  always  have 
been  famous  and  is,  we  believe,  by  far 
the  most  economical  source  of  "B" 
current  obtainable. 

Manufactured  and  guaranteed  by 

NATIONAL    CARBON    CO.,    Inc. 
New  York  San  Francisco 

Canadian  National  Carbon  Co.,  Limited,  Toronto,  Ontario 

t EVEREADY  HOUR  EVERYTUESDAY  at  8  P.M.' 
Eastern  Standard   Time 
Beginning   Sept.    29th.    9   P.    M.    Eastern  Standard   Time  \ 
For  real  radio  enjoyment,   tune  in   the  "Eveready 
Group."     Broadcast  through  stations — 
WEAF  New  York        WGR     Buffalo        WWJ        Detroit 
WJAR  Providence     WCAE  Pittsburgh  „,-.-  (  Minneapolis 
WE  El  Boston  wccoist.Paul 

WFI      Philadelphia  WSAI  Cincinnati  WOC       Davenport    J 

EVEREADY 

Radio  Batteries 

-  they  last  longer 


11111 


¥     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


T^HE  radio  public  is  growing  wise  in  its  mod- 
ern day  and  generation.  No  longer  is  it 
possible  for  an  imaginative  individual  to  make 
a  great  stir  by  announcing  that  he  has  dis- 
covered that  "they  are  working  on  something 
right  now  that  is  going  to  revolutionize  radio." 
Set  buyers,  in  the  early  years  of  broadcasting, 
were  inclined  to  believe  from  the  miraculous 
development  of  radio  communication  were  to 
result  other  miracles.  Rapid,  revolutionary 
changes  in  the  methods  of  transforming  radio 
impulses  into  sound  signals  were  promised 
by  irresponsible  individuals  in  1921,  in  1922,  in 
1923,  in  1924  and  occasionally  even  now  we 
read  or  hear  the  well  worn  statement  that  new 
and  marvelous  things  are  soon  to  stun  the 
public. 

We  venture  to  say  that  the  number  of  per- 
sons who  hesitate  today  about  buying  radio 
equipment  for  fear  that  they  will  find  their 
receivers  obsolete  in  a  short  while  is  smaller 
than  it  ever  was  and  growing  smaller  each  day. 
Radio  fans  have  come  to  the  conclusion  that 
there  is  no  more  sense  in  deferring  buying  a 
radio  set  because  sets  may  be  changed  consid- 
erably in  the  years  to  come  than  there  is  in 
refusing  to  buy  automobiles  at  this  time  on  the 
presumption  that  motor  cars  two  years  hence 
will  be  superior  to  those  of  today. 

Figures  given  out  by  an  official  of  the  United 
States  Bureau  of  Standards  recently  estimated 
that  from  one  third  to  one  half  of  the  people 
of  this  country  now  have  access  to  radio  pro- 
grams through  receiving  apparatus.  Those 
who  have  not  installed  radio  equipment  in  their 
homes  would  better  hasten  or  they  may  find 
that  they  have  rejected  from  their  lives  a  new 
social  factor  which  is  one  of  the  amazing  devel- 
opments making  it  so  worth  while  to  live  in  this 
age  of  progress. 


T\R.  J.  H.  DELLINGER,  able  engineer  who 
is  chief  of  the  radio  laboratory  of  the  Bu- 
reau of  Standards,  says: 

"We  now  have  not  so  much  the  invention  of 
devices  but  the  perfection  of  them.  This  state- 
ment is  very  general.  Nevertheless,  broadly 
speaking,  radio  engineering  has  now  taken 
definite  form  and  is  the  tool  by  which  progress 
in  radio  is  being  wrought." 

Then  Dr.  Dellinger  makes  the  following" 
clear  statement  of  the  progress  radio  has  made : 

"Substantial  progress  has  been  going  on  all 
along  the  line  of  radio  engineering.  Thus,  in 
the  development  of  new  and  improved  radio 
communication  methods  or  systems,  we  have 
great  extension  of  the  available  frequency 
range,  marked  improvements  in  directive  radio 
transmission,  advances  in  the  perfection  of 
selective  radio  systems,  and  engineering  devel- 
opment of  line-radio  or  carrier-current  com- 
munication. Among  radio  devices  and  appli- 
cations of  radio  there  is  outstanding  progress  on 
radio  beacons,  on  the  uses  of  radio  for  air- 
craft navigation,  on  direction  finders,  and  on 
radio  picture  transmission  and  vision.  In  the 
field  of  research  and  study  of  the  problems  of 
radio,  we  have  important  progress  going  on  in 
radio  measurements,  in  standardization  of 
apparatus,  in  the  study  and  mitigation  of  the 
vagaries  of  wave  propagation  and  atmos- 
pheric disturbances,  and  in  the  wide  reaches  of 
the  interference  problem." 

TT  WILL  be  observed  that  there  is  no  predic- 
tion in  the  foregoing  that  even  suggests 
"revolutionary"  changes  in  radio.  We  would 
suggest  that  those  who  have  been  disturbed  by 
sensational  forecasts  of  radio  give  ear  to  Dr. 
Dellinger's  views.  He  is  a  scientist  who  is  not 
personally  interested  in  the  commercial  as- 
pects of  the  new  art  and  his  statements  may  be 
accepted  as  sound  and  unbiased. 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour  5 


Its  mahogany  to  the  eye- 

but  in  fact  its  ^bakclitc 


Bakelite  is  an  exclusive 
trade  mark  and  can  be 
used  only  on  products 
made  from  materials 
manufactured  by  the 
Bakelite  Corporation. 
It  fs  the  only  material 
which  may  bear  this 
famous  mark  of  excel- 
lence. 


So  perfectly  is  the  grain  and  color 
of  mahogany  and  walnut  repro- 
duced in  these  Bakelite  Radio  Panels, 
that  the  eye  cannot  distinguish  them 
from  the  natural  woods. 

By  using  a  Bakelite  Panel  that 
matches  the  wood  in  the  cabinet, 
your  finished  set  will  be  far  more 
handsome  than  if  a  plain  panel  is 
used. 

Rigid  and  strong,  Bakelite  Panels 
support  the  weight  of  heavy  instru- 
ments without  sagging.  They  will 
not  compress,  or  cold-flow,  under 
pressure  of  binding  screws.  Because 
of  their  resistance  to  extremes  of 
heat,  cold  and  moisture,  they  will 
not  warp  nor  split.  These  properties 
and  their  insulation  value,  color 
and    finish    are    permanent. 

Be  sure  to  ask  your  dealer  to  show 
you  these  wood  finish  Bakelite  Panels 
— obtainable  under  any  of  the  follow- 
ing   trade-names : 


j^jmnlHiim 


Dikcto 

Eibroc   Mtearta 


A  Bakelite  Panel  on  a  set  is  an 
indication  that  the  manufacturer 
has  used  the  best. 

Write  for  Booklet  31 
BAKELITE    CORPORATION 

247  Park  Avenue,  New  York,  N.  Y. 
Chicago  Office:  636  West  2 2d  Street 


BAKELITE 

is  the  registered  trade 
mark  for  the  phenol 
resin  product  manu- 
factured under  pat- 
ents owned  by  the 
Bakelite  Corporation. 


THE    MATERIAL    OF  A  THOUSAND 

*     Tested  and  Approved  by  RADIO  AGE     * 


USES 


6  RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


AN  attractive  cabinet  can  never  make  an 
Ozarka  out  of  any  other  radio.  Far  too 
many  radio  buyers  pay  more  attention  to 
the  outer  appearance  and  not  enough  to  the 

When  your  automobile  runs  as 
the  manufacturer  intended  it 
should,  it  is  a  real  pleasure  to 
drive  it.  But  what  do  you  do 
when  something  goes  wrong? 
Do  you  immediately  condemn 
the  car? — no.Do  you  call  in  some 
handy  man  who  can  fix  any- 
thing? —  no. 

You  send  for  a  service  man 
who  is  trained  in  repairing  your 
make  of  car.  To  correct  the 
fault  is  easy  for  him  because  he 
knows.  Some  other  mechanic 
might  have  to  tear  the  car  apart 
to  locate  the  trouble. 
The  same  is  true  of  radio,  no 
matter  what  price  you  pay— 
you  will  sometimes  need  the 
service  of  a  service  man.  If  he 
is  factory  trained  and  experi- 
enced he  can  and  will  deliver 
the  kind  of  service  you  know 
you  ought  to  have. 

Ozarka  instruments  are  only 
sold  by  direct  factory  repre- 
sentatives who  are  required  to 
take  a  complete  course  of  in- 
structions of  Ozarka  service 
directly  under  Ozarka  engi- 
neers.   By  so  doing   we  are 


Cven  if  I  had 
your  Furl  Wouldn't 
Be  a  Rabbit  — 

inside.  The  service  behind  the  radio  you  buy 
is  even  more  important  than  the  inside  or 
outside — your  satisfaction  depends  on  it.  Let 
us  see  just  what  radio  service  is. 

assured  that  every  purchaser     W/^  XT  p*^rl    a    "FVw  A/f  r**»  p» 
of  an  Ozarka  will  have  an  ex-      we  ^  eea   a  r  e  w  IVlOre 

perienced  service  man  within  Ozarka  Representatives 


his  reach  at  all  times.    3100 

such  men  today  comprise  the  Ozarka 
service  organization  —  more  are  being 
added  daily.  Ozarka  service  does  not 
add  a  single  cent  to  the  price  you  pay  for 
your  radio— then  why  not  benefit  by  it? 
And  remember,  Ozarka  is  a  radio  in- 
strument built  of  the  finest  units,  care- 
fully and  correctly  designed  exteriorly 
and  interiorly.  Cabinets  are  ultra  mod- 
ern, finely  finished — a  most  attractive 
addition  to  the  appointments  of  the 
beautifully  furnished  home. 
Ozarka  circuits  have  proved  themselves 
for  four  years  by  comparison  with  other 
high  grade  receiving  sets.  Whether  you 
plan  on  installing  a  radio  in  your  home, 
now  or  later,  you  deserve  to  hear 
the  Ozarka.  The  Ozarka  man  will 
demonstrate  the  Ozarka  to  you  right 
in  your  own  home — under  exactly  the 
same  conditions  you  will  continue  to 
use  your  set.  Then  there  can  be  no 
disappointment  later. 
Ozarka  instruments  are  only  sold  in 
competition  side  by  side  with  others — 
you  do  your  own  tuning  and  therefore 
decide  for  yourself  just  what  an  Ozarka 
will  do  for  selectivity,  distance,  volume 
and  above  all,  tone. 

Send  for  the  book  Ozarka  Instruments 
No.  200;  please  give  name  of  your 
county  and  we'll  gladly  have  our 
Ozarka  representative  arrange  a  dem- 
onstration for  you  in  your  own  home. 


1 22  Austin  Avenue  A 
Chicago,  Illinois 


Gentlemen:  Without  obligation  send  book  "Ozarka  Instru- 
ments No.  200"  and  name  of  Ozarka  representative. 

9-25-122A 
Name 


Address 

County 


....City. 
.State..., 


"DADIO  offers  a  wonderful  opportunity 
±v  to  men  who  wish  to  get  into  business 
for  themselves.  It  is  work  that  can  be 
done,  at  the  start,  in  the  evenings  and  in 
your  spare  time.  You  can  hold  your  pres- 
ent position  and  learn  radio  under  our  plan. 
Ozarka  instruments  have  been  on  the  mar- 
ket for  four  years — they  have  successfully  met  all 
competition.  Ozarka  representatives  have  made  good, 
not  only  because  Ozarka  Instruments  are  right  but 
because  our  training  in  both  selling  and  service  is 
the  most  complete  possible. 

All  we  ask  is  that  you  are  willing  to  purchase  your 
demonstrating  instrument  and  willing  to  learn  what 
we  are  willing  to  teach  you. 

We  have  proven  with  3100  men  that  with  this  training 
you  can  make  good  in  radio.  The  Ozarka  sales  course 
consists  of  twelve  lessons; — a  real  course  in  salesmanship  that 
costs  you  nothing — our  training  in  service  is  so  complete  that 
you  will  know  Ozarka  Instruments  in  every  detail. 
The  man  we  want  is  somewhat  mechanically  inclined — he  is 
steady,  industrious,  has  lived  in  his  community  some  time.  He 
stands  well,  not  because  he  has  money  but  because  he  has  con- 
ducted himself  in  a  manner  to  gain  the  respect  of  his  fellow 
men.  He  may  not  have  much  money  but  he  is  not  broke.  He 
has  a  job  but  may  still  be  having  trouble  in  making  both  ends 
meet.    He  really  wants  a  business  of  his  own. 

Send  Coupon  for  FREE  Book 

To  such  a  man.  who  will  freely  tell  us  something  about  himself 
we  will  gladly  send  a  copy  of  the  Ozarka  Plan  No.  100,  a  rather 
unusual  book.  Yon'll  find  it  interesting  because  it  proves  why 
some  men  are  millionaires  and  how  others  made  them  so— why 
some  men  get  to  the  top  while  others  don't— best  of  all  it 
will  show  you  how  you  can  make  more  money  and  become 
really  independent.  Send  for  it  today,  but  please  mention  the 
name  of  your  county. 

122  Austin  Avenue  A 
Chicago,  Illinois 

Gentlemen:  I  am  greatly  interested  in  the  FREE  book  "1  he 
Ozarka  Plan"  whereby  I  can  sell  your  radio  instruments 

9-25-  122A 


Address City. 

County State. . . 


*     Tested  and  Approved  by  RADIO  AGS     * 


AUG  25l92i)ciB666U9 

RADIO  AGE  for  September,  1925 

3Q[ 


The  Magazine  of  the  Hour 


sac 


Jfie  Magazine  (fthe  Hour 


M.  B.  Smith 

Business  Manager 


A  Monthly     Publication 

Devoted  to  Practical 

Radio 


Frederick  A.  Smith  j= 

Editor 


L=1EH=^==]E]E 


SEE 


3BI "="= 


="=" '""  '"" »="= 


SEE 


Thirty-One  Proven  Ways  to 

PREVENT  Self-Oscillations 


SUPPRESSING  self-oscillations  or 
audio  oscillations  in  the  radio  fre- 
quency stages  of  reflex  or  radio  fre- 
quency circuits  is  a  problem  of  the  first 
magnitude.  The  efficiency  of  the  stab- 
ilizing devices  used  to  accomplish  this 
result  determines  the  efficiency  of  all  cir- 
cuits employing  radio  frequency  amplifi- 
cation, the  tone  of  the  receiver  and  its 
tuning  ability.  In  fact,  the  principal  dif- 
ference between  the  many  "dynes"  now 
on  the  market  lies  in  the  method  of  sup- 
pressing these  audible  oscillations  rather 
than  the  means  of  procuring  amplification 
or  tuning.  Unfortunately,  no  two  cir- 
cuits employing  different  units  will  act 
the  same  with  a  given  type  of  stabilizer 
and  as  a  result  we  must  try  out  the 
various  systems  experimentally  until  we 
find  the  one  best  suited  to  the  particular 
conditions  at  hand — a  tedious  and  nerve 
racking  trial  to  say  the  least. 

Excessive  regeneration  in  the  radio  fre- 
quency stages,  due  to  stray  magnetic 
fields  or  audio  frequency  feedbacks,  are 
the  most  frequent  causes  of  free  oscilla- 
tions. Again,  highly  efficient  tuning  units 
with  a  very  low  resistance  will  also  allow 
free  oscillations  to  take  place  which  would 
be  damped  down  completely  in  less  effi- 
cient circuits  having  higher  resistance. 
Sharp  tuning  inductances  are  more  prone 
to  the  trouble  than  coils  having  higher 
losses  and  less  selectivity,  while  induct- 
ances generating 
eddy  currents  in 
adjacent  metal 
parts  may  be 
perfectly  stable 
because  of  the  ab- 
sorption of  the 
excess  energy 
causing  the  oscill- 
ations. Conditions 
which  favor  dis- 
tance reception  do 
not  tend  to  result 
in  stability,  hence 
a  circuit  with  pro- 
nounced DX  qual- 
ities is  more  gener- 
ally noisy  than  a 
"dud"  due  to  the 
strong  regenera- 
tive factor  existing 
in  the  DX  cir- 
cuit. Perfect  sta- 
bility means  the 
sacrifice  of  other 
qualities  as  a  rule, 
for  stability  re- 
quires "lossing"  in 


By  ROSCOE  BUNDY 


Copyright:   1925 


A  Detailed  Analysis 
of  R.  F.    Stabilizers 


the  circuit  and  a  minimum  regeneration. 
All  of  us  who  have  attempted  experi- 
mental work  with  radio  frequency  or  re- 
flex circuits  have  at  some  time  experi- 
enced the  terrific  howls  due  to  audio  fre- 
quency oscillations,  or  have  noted  the 
sudden  blocking  and  grid  "flopping"  that 
is  due  to  self-oscillations  at  frequencies 
approaching  the  frequency  of  the  incom- 
ing radio  waves.  The  tube  oscillations 
under  these  conditions  can  no  longer  be 
controlled  by  the  tuning  devices  with  the 
result  that  the  signals  are  much  weakened 
or  entirely  eliminated.  In  other  words, 
with  excessive  regeneration,  the  radio 
frequency  tubes  act  as  independent  oscil- 
lators, oscillating  at  their  own  particular 
frequency  without  regard  to  the  fre- 
quency of  the  incoming  signals.  They  are 
"out-of-step"  with  the  impressed  oscil- 
lations', hence  no  amplification  is  per- 
formed.    The  signals  may  come  in  strong 


up  to  a  certain  position  of  the  tuning  con- 
trols, and  then  without  warning  the  tube 
"flops"  and  the  signals  entirely  disappear 
or  else  violent  shrieking  and  howling 
take  place. 

Where  excessive  regeneration  is  caused 
by  stray  magnetic  fields  acting  on  the 
tuning  unit  (See  Fig.  1),  radio  frequency 
transformers  or  wiring,  conditions  can 
generally  be  improved  by  a  re-arrange- 
ment of  the  apparatus  and  wiring  so  that 
it  is  not  cut  by  the  stray  magnetic  field  or 
else  we  can  employ  the  so-called  "field- 
less"  coils  of  the  circloid  type  which  do 
not  cause  interstage  coupling.  In  many 
cases  the  trouble  may  be  minimized  or 
eliminated  by  a  slight  change  in  the 
angles  of  the  couplers  and  radio  frequency 
transformers,  by  separating  the  grid 
wires  from  the  plate  circuit  wires,  or  by 
introducing  resistances  into  the  circuit. 
With  receiving  sets  having  closely  crowded 
apparatus  such  procedure  is  not  always 
possible,  and  we  must  therefore  fall  back 
on  some  independent  or  external  stabiliz- 
ing device  that  will  absorb  the  excess 
energy. 

The  Feedback  Problem 

FEED-BACK  through  the  "grid-to- 
plate"  capacity  of  the  tube  is  pro- 
ductive of  oscillations,  and  as  this  ca- 
pacity cannot  be  altered  within  the  tube 
itself,  it  generally  requires  some  sort  of 
neutralizing 
scheme  by  which 
the  internal  cap- 
acity of  the  tube 
is  opposed  by  an 
external  balancing 
condenser  as  in  the 
Neutrodyne,  o  r 
else  by  some  other 
arrangemen  t 
which  opposes  the 
transfer  of  energy 
taking  place  be- 
tween the  grid  and 
plate.  Condenser 
action  between 
parallel  grid  and 
plate  wires  causes 
the  same  effect  as 
the  grid-plate — 
capacity  for  these 
wires  are  simply 
continuations  of 
the  grid  and  plate 
elements.  Very 
frequently  the 
trouble  is  charged 
to  the   tube   when 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


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the  wires  leading  to  the  tube  or  the  socket 
are  really  to  blame.  A  neutralizing  con- 
denser having  ample  capacity  for  neu- 
tralizing the  grid-plate  capacity  of  the 
tube  may  not  be  large  enough  to  take  care 
of  the  additional  capacity  of  the  wiring; 
hence  we  often  meet  with  circuits  which 
cannot  be  neutralized  by  the  commercial 
neutrodons  or  condensers. 

Probably  the  simplest  test  for  deter- 
mining regenerative  feed-backs  and  self- 
oscillations  is  to  remove  one  or  more  of 
the  radio  frequency  tubes  from  its 
socket  without  disturbing  or  shutting 
down  the  rest  of  the  circuit.  If  the  signal 
still  keeps  coming  in  with  the  R.  F.  tubes 
removed,  it  is  certain  that  energy  is  being 
coupled  back  to  the  detector  tube  by  stray 
magnetic  fields  or  by  capacity-coupling 
through  the  circuit  or  tubes.  Under  such 
conditions,  the  radio  frequency  tubes 
have  but  little  effect  when  replaced  in 
their  sockets,  and  the  rheostat  must  be 
turned  full  on  before  there  is  any  ap- 
preciable increase  in  signal  strength 
through  the  tubes.  Up  to  a  certain  point 
this  back-coupling  may  not  produce  noise 
or  audible  oscillations,  but  if  it  is  carried 
far  enough  with  strong  enough  coupling, 
we  will  be  certain  to  hear  the  character- 
istic howls  and  shrieks.  With  a  perfectly 
neutralized  circuit  without  interstage 
feed-back,  the  signals  will  cease  instantly 
when  either  of  the  radio  frequency  tubes 
is  removed  from  its  socket. 

Even  with  a  very  slight  feed-back,  free 
oscillations  will  persist  in  a  low  resistance 
circuit,  and  if  the  resistance  is  reduced 
to  zero  the  oscillations  will  continue  in- 
definitely without  the  application  of 
further  external  energy.  Resistance  or 
electrical  friction  damps  down  oscillations 
in  the  same  way  that  mechanical  friction 
brings  a  swinging  body  to  rest,  hence 
some  resistance  must  be  present  in  a 
stable  circuit  even  though  it  does  reduce 
its  efficiency  as  a  receiver  of  radio  waves. 
It  is  here  that  regeneration  produces  a 
secondary  effect  favorable  to  the  estab- 
lishment of  free  oscillations,  for  regenera- 
tion reduces  the  resistance  of  the  circuit 
even  to  the  point  where  we  may  obtain 
"negative  resistance."  With  negative 
resistance,  where  the  resistance  is  "less 
than  nothing,"  the  oscillations  not  only 
persist  but  they  actually  increase  in 
amplitude  until  they  build  up  to  the 
saturation  point  of  the  tube  and  cause 
spilling. 

To  gain  an  idea  of  the  magnetic  coup- 
ling between  adjacent  coils  we  will  return 
to  Fig.  1  where  the  transformer  coil  (1) 
generates  a  magnetic  field  which  cuts 
through  the  turns  of  the  coupler  coil  (2), 
inducing  a  current  in  the  latter  coil.  This 
magnetic  coupling  effect  is  at  a  maximum 
when  the  axes  of  the  coils  are  parallel  as 
shown.  At  the  left  is  a  plate  (PLT)  which 
is  cut  by  the  stray  field,  causing  eddy  cur- 
rents to  be  generated  in  the  plate  just  as 
currents  are  generated  in  the  coupler  coil 
(2).  With  the  coils  in  this  position,  ex- 
cessive regeneration  will  be  produced  in 
the  coupler  coil  (2)  which  will  set  up  free 
oscillations.  An  energy  loss  will  take  place 
in  the  plate  (PLT),  and  so  much  energy 
will  be  transferred  between  the  coils  that 
the  radio  frequency  tubes  will  be  prac- 
tically short  circuited  and  rendered  in- 
effective. 

In  Fig.  2  the  coils  are  turned  at  right 
angles,  and  if  the  magnetic  lines  were  per- 
fectly straight  instead  of  being  curved  as 
shown,  the  transformer  coil  (Tl)  would 
not  couple  magnetically  with  coil  (T2) 
for  the  field  would  pass  along  the  wires 
and  not  cut  across  them.  In  the  same 
way,  a  stray  field  (c)  would  not  generate 
a  current  in  coil  (C),  but  a  wave  or  field 
(a)  passing  along  the  axis  will  generate 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour  9 


and  couple  in  coil  (Tl).  However,  the 
magnetic  lines  are  curved,  hence  there  is 
always  a  component  that  will  cause  a 
slight  coupling.  Again,  the  two  coils  act 
like  the  plates  of  a  condenser  so  that  there 
is  a  "capacity  coupling"  in  addition  to 
the  slight  magnetic  coupling  noted.  To 
prevent  trouble,  we  must  either  turn  the 
coils  at  some  angle  where  the  coupling 
is  practically  zero,  or  else  separate  them 
sufficiently  so  that  the  coupling  will  be 
feeble. 

In  Fig.  3  we  have  the  familiar  arrange- 
ment of  the  coupler  (T2)  and  the  trans- 
former (Tl)  as  used  in  many  radio 
frequency  sets.  The  coils  are  turned  at 
such  an  angle  that  the  magnetic  lines  of 
(Tl)  cause  the  least  possible  induction 
in  (T2).  At  the  same  time,  the  spacing 
(M)  is  such  that  the  coil  sides  (m)  and 
(n)  do  not  face  each  other,  thus  avoiding 
capacity  coupling.  If  (m)  and  (n)  were 
opposite  and  parallel,  instead  of  being 
offset  by  the  distance  (b),  we  would  have 
troublesome  capacity  coupling  between 
the  two  circuits  which  would  be  almost 
as  bad  as  the  magnetic  coupling. 

Classification  of  Stabilizers 

IN  GENERAL,  radio  frequency  stabil- 
izers can  be  classified  under  the  follow- 
ing heads.  In  some  cases  the  stabilizers 
are  purely  "lossers;"  that  is,  suppress 
oscillations  by  introducing  direct  losses 
into  the  circuit  while  others  oppose  the 
amplitude  without  actual  resistance 
losses  introduced  into  the  incoming  signal 
waves. 

1.  RESISTANCE  STABILIZERS  where  con- 
trol is  had  by  the  introduction  of  resistances 
in  the  plate  or  grid  circuit. 

2.  GRID  POTENTIAL  STABILIZERS  by 
which  a  constant  or  variable  negative  charge 
is  applied  to  the  grid  of  the  tube  to  reduce  its 
tendency  toward  oscillation.  Often  called 
"Biasing." 

3.  ANTENNA  COUPLER  ARRANGEMENT 
by  which  the  tendency  to  oscillate  is  subdued 
by  the  use  of  single  circuit  antenna  couplers 
or  by  capacities  introduced  into  the  antenna 
circuit. 

4.  ABSORPTION  STABILIZERS  consisting 
of  an  inductively  coupled  control  circuit  in 
which  losses  or  opposing  currents  may  be 
produced. 

5.  EDDY  CURRENT  STABILIZERS  in  which 
the  excess  energy  is  dissipated  by  the  genera- 
tion of  eddy  currents  in  metal  plates. 

6.  INDUCTIVE  REVERSED  FEED-BACK 
STABILIZERS  where  a  reversed  tickler  feed- 
back coil  inductively  controls  the  amplitude 
of  the  oscillations. 

7.  CAPACITY  FEED-BACK  STABILIZERS 
in  which  a  reversed  feed-back  is  had  through 
a  condenser,  the  plate  being  connected  to  the 
grid  circuit  through  the  condenser  so  that 
opposing  wave  systems  are  produced. 

8.  BALANCING  STABILIZERS  in  which  the 
tendency  of  the  inductance  to  cause  oscilla- 
tions is  reduced  by  intermediate  balancing 
taps  in  the  coils. 

9.  GRID  NEUTRALIZATION  STABILIZERS 
using  a  grid  to  grid  capacity  which  opposes  the 
grid  to  plate  capacity  of  the  tube. 

10.  CHOKE  COIL  STABILIZERS  consisting  of 
an  inductance  or  choke  which  damps  down 
the     oscillations. 

11.  CAPACITY  BRIDGE  STABILIZERS  using 
balancing  condensers  for  the  grid  return  or 
other  parts  of  the  circuit. 

Resistance  "Lossers" 

BY  THE  introduction  of  relatively 
high  ohmic  resistances  in  various 
parts  of  the  circuit  we  can  often  damp 
down  the  free  oscillations  by  virtue  of 
the  electrical  "friction"  introduced,  but 
this  leads  to  losses  in  sensitivity  and 
volume  so  that  the  resistance  "lossers" 
are  not  always  desirable.  Further,  they 
generally  reduce  the  selectivity  when 
used  in  the  grid  circuit  unless  they  can 
be  varied  accurately  to  meet  changes  in 
wavelength,  and  this  is  another  serious 
objection.  The  various  methods  of 
introducing  resistance  are  as  follows: 

FIG.  4.  RESISTANCE  IN  GRID 
CIRCUIT.  By  introducing  the  fixed 
resistances  (Rl)  or  (R2)  into  the  grid 
circuit    we   can    sometimes    damp    down 


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oscillations  if  they  are  not  too  severe,  but 
at  the  same  time  we  lose  sentitivity  and 
volume.  Such  resistances  will  vary  from 
5,000  to  20,000  ohms  and  are  of  the  grid 
leak  type.  By  connecting  a  small  fixed 
condenser  (K)  across  the  resistance  (R2) 
in  the  grid  return  we  can  sometimes  work 
a  decided  improvement  in  the  sensitivity. 
Here  we  have  the  usual  coupler  with  the 
primary  (LI)  and  secondary  (L2)  tuned 
by  the  variable  condenser  (C).  This 
may  be  applied  to  the  first  or  second  stage 
or  to  both. 

The  Fixed  Leak 

FIG.  5.  FIXED  LEAK.  Here  we 
connect  a  fixed  resistance  (Rl)  of  from 
10,000  to  40,000  ohms  resistance  between 
the  grid  and  the  —A.  This  gives  a 
negative  bias  to  the  tube,  but  as  it  also 
grounds  an  appreciable  percentage  of  the 
grid  charge,  it  weakens  the  signal  strength 
and  reduces  the  selectivity.  Condenser 
(K)  is  a  stop  condenser  which  reduces 
losses  to  ground.-     Its  use  is  not  advised. 

FIG.  6.  VARIABLE  RESISTANCE. 
A  variable  resistance  placed  in  the  grid 
return  circuit  is  sometimes  effective, 
but  as  this  calls  for  another  control  in 
addition  to  the  regular  control  it  is 
not  the  best  proposition  on  earth.  It  is 
far  more  effective  than  the  fixed  resist- 
ances, however,  and  is  really  quite  critical 
to  wavelength.  Either  a  200  or  a  400 
ohm  potentiometer  can  be  used  at  (PO), 
connected  up  like  a  rheostat,  but  the 
400  ohm  potentiometer  is  sometimes 
made  necessary  when  there  is  a  particularly 
strong  tendency  toward  free  oscillations. 

FIG.  7.  RESISTANCE  IN  PLATE 
CIRCUIT.  Here  a  fixed  or  variable 
resistance  (Rl)  of  from  10,000  to  50,000 
ohms  is  inserted  into  the  plate  circuit 
of  the  tube  and  in  series  with  the  primary 
winding  (LI)  of  the  radio  frequency 
transformer.  It  is  fairly  effective  if  the 
oscillating  tendency  is  not  too  great 
and  causes  less  loss  in  sensitivity  and 
selectivity  than  when  such  resistances 
are  inserted  in  the  grid  circuit.  For  the 
best  results  it  should  be  individually 
adjusted  to  each  circuit. 

FIG.  8.  REVERSED  PLATE  RE- 
SISTANCE. Here  a  portion  of  the 
plate  current  is  fed  back  into  the  coupler 
primary  by  the  variable  resistance  (Rl), 
the  feed-back  current  opposing  the  estab- 
lishment of  the  free  oscillations.  The 
resistance  will  vary  between  50,000  and 
100,000  ohms  in  the  majority  of  cases, 
but  has  the  objection  that  it  is  critical 
to  wavelength  and  must  be  tuned  with 
the  main  controls.  However,  it  is 
usually  quite  effective  even  when  the 
tendency   to   oscillate   is   strong. 

FIG.  9.  BALANCED  GRID  RE- 
TURN. In  this  case  we  connect  the 
grid  return  line  of  the  first  tube  to  the 
midpoint  (P)  of  the  secondary  coil 
(L4)  of  the  second  radio  frequency 
transformer.  A  fixed  resistance  (Rl) 
is  in  series  with  the  return,  and  the 
potentiometer  (PO)  assists  in  main- 
taining stability.  It  is  quite  effective 
and  loses  less  energy  than  most  of  the 
resistance    systems. 

Grid  Biasing  Methods 

AMONG  the  most  popular  of  the 
stabilizers,  as  well  as  among  the 
oldest,  are  those  which  function  by 
controlling  the  potential  on  the  grid  of 
the  tube.  By  giving  the  grid  a  negative 
charge  or  "bias"  we  increase  the  sensi- 
tivity, stability,  and  clearness  of  recep- 
tion, but  such  methods  alone  are  not 
always  sufficient  to  stop  free  oscillations. 
By   maintaining  a  negative  bias  on  the 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


11 


tubes,  the  "B"  battery  consumption 
is  also  reduced. 

FIG.  10.  POTENTIOMETER  ME- 
THOD. Here  we  have  the  old  and 
much  used  potentiometer  system  of 
grid  potential  control  with  the  poten- 
tiometer (PO)  connected  directly  across 
the  "A"  battery,  and  with  the  slider 
(S)  connected  to  the  grid  return.  By 
means  of  the  potentiometer  we  can  vary 
the  grid  potential  continuously  from  the 
maximum  negative  value  to  the  maxi- 
mum positive  value  by  moving  the 
slider  (S)  to  different  points  along  the 
coil.  This  control  is  very  marked  in 
most  circuits  and  causes  less  loss  than 
the  pure  resistance  control  shown  in  the 
first  three  figures,  but  it  adds  another 
critical    tuning    control    to    the    list. 

In  addition  to  its  use  as  a  stabilizer 
its  marked  effect  on  the  tone  has  led  it 
to  be  marked  "Clarifier"  on  the  panels 
of  commercial  radio  sets.  By  its  means 
we  can  clear  up  any  distortion  or  "mush" 
that  may  be  due  to  the  radio  frequency 
stages,  but  of  course  this  has  no  effect 
on  the  distortion  caused  by  the  audio 
amplifying  transformers.  About  the 
only  objection  to  this  device  is  the  fact 
that  it  permits  the  operator  to  put 
a  positive  bias  on  the  grid,  and  thus 
may  cause  excessive  "B"  battery  con- 
sumption if  not  carefully  handled.  The 
resistance  averages  from  200  to  400 
ohms  in  the  commercial  types  with  an 
occasional  example  of  from  1,000  to 
1,500  ohms.  The  higher  the  resistance 
the   more   accurate   will   be   the   control. 

It  is  usually  advisable,  although  not 
absolutely  necessary,  to  connect  a  fixed 
bypass  condenser  (K)  between  the 
potentiometer  slider  (S)  and  the  (—A) 
line.  This  reduces  the  resistance  to  the 
radio  frequency  current  due  to  the 
inductance  of  the  resistance  coil  and 
also  to  its  ohmic  resistance.  The  value 
of  (K)  is  not  critical,  but  it  is  generally 
a  0.005  mf.  or  0.006  mf.  condenser. 
The  maximum  biasing  voltage  that  can 
be  applied  to  the  grid  is  equal  to  the 
voltage  of  the   "A"   battery. 

FIG.  11.  BIASING  "C"  BATTERY. 
Another  method  (not  so  good)  is  to  apply 
a  constant  negative  bias  to  the  grid 
by  means  of  a  "C"  or  "biasing  battery" 
as  shown  by  Fig.  11.  This  consists  of 
from  one  to  three  cells  of  small  dry 
battery  connected  to  the  grid  by  their 
negative  leads.  The  trouble  with  such 
an  arrangement  is  that  the  voltage 
cannot  be  varied  to  meet  the  require- 
ments of  strong  and  weak  signals,  but 
it  is  simple  and  cheap  and  sometimes 
is  very  effective  in  reducing  free  oscilla- 
tions and  of  increasing  the  volume  of 
strong  local  stations.  With  90  volts 
on  the  plate  of  the  tube,  it  is  usual  to 
employ  a  maximum  of  three  cells  (4.5 
volts)  on  the  grid  for  local  stations,  this 
giving  a  maximum  volume.  However, 
it  reduces  the  distance  and  sensitivity  to 
weak  signals,  and  for  distance  this  should 
be  reduced  to  about  1.5  volts  or  a  little 
more.  There  is  no  drain  on  the  "C" 
battery  for  it  dies  of  old  age  rather  than 
wears    out. 

FIG.  12.  DOUBLE  BIASING  PO- 
TENTIOMETER. We  can  place  a 
variable  bias  on  both  tubes  of  a  two  tube 
radio  frequency  set  by  the  potentiometer 
method  of  Fig.  12.  Here  the  (  — F)  posts 
of  both  transformer  secondaries  are  con- 
nected to  the  potentiometer  slider,  and 
thus  both  tubes  receive  an  equal  bias. 
This  is  usually  the  best  method,  for  both 
tubes  are  then  fully  controlled  directly. 

FIG.  13.  CONTROLLED  "C"  BAT- 
TERY. Here  a  potentiometer  (PO)  is 
connected    across    the    "C"    battery    so 


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RADIO  AGE /or  September,  1925 


that  the  bias  can  be  accurately  controlled. 
The  potentiometer  slider  goes  to  the  grid 
of  the  tube.  This  is  rather  complicated, 
and  a  switch  (SW)  must  be  opened  when 
we  are  through  with  the  set  so  that  the 
battery  will  not  be  run  down  by  discharg- 
ing through  the  potentiometer  coil  when 
idle.    The  method  of  No.  12  is  preferable. 

Antenna  Coupler  Methods 

GENERAL.  The  tendency  toward 
free  audio  oscillations  in  the  first 
radio  tube  is  greatly  influenced  by  the 
method  adopted  in  coupling  the  circuit 
to  the  antenna.  Up  to  this  point  we 
have  shown  the  conventional  aperiodic 
type  fixed  coupler  in  which  the  primary 
is  inductively  coupled  to  the  secondary 
coil,  but  this  is  not  the  only  method 
available  when  more  than  one  radio 
frequency  tube  is  employed.  A  coupler 
of  this  type,  while  possessing  the  virtue 
of  selectivity,  offers  little  resistance  to 
free  oscillations.  A  single  circuit  type 
is   more   resistant   to   free   oscillations. 

FIG.  14.  SIMPLE  TUNED  IN- 
DUCTANCE. Here  we  have  the  single 
coil  (LI)  tuned  by  the  variable  con- 
denser (Cl).  This  is  not  at  all  selective, 
and  cannot  be  used  in  places  where  a 
sharp  tuning  outfit  is  necessary  unless 
we  have  at  least  two  stages  of  radio 
frequency  and  three  tuned  inductance 
controls  in  the  circuit.  It  retards  oscilla- 
tions, however,  and  brings  in  better  dis- 
tance and  louder  signals  than  the  aperi- 
odic type  when  properly  used  in  the  cir- 
cuit. It  may  be  a  honeycomb  of  50 
turns,  a  spiderweb,  or  simple  solenoid  coil. 

FIG.  15.  VARIOMETER  TUNING. 
The  variometer  (VAR)  is  a  variable 
tuning  inductance  with  which  no  vari- 
able condenser  is  required.  Its  tendency 
toward  oscillation  is  even  less  than  with 
the  plain  inductance  as  there  is  no  con- 
denser, and  further,  better  signal 
strength  is  had  for  the  reason  that  higher 
grid  potentials  are  possible  with  a  pure 
inductance  than  with  a  capacity  and 
inductance  combined.  As  an  aid  to 
selectivity,  a  fixed  condenser  (K)  of  from 
0.0001  mf.  to  0.00025  mf.  may  be  inserted 
in  the  aerial,  but  this  is  not  necessary 
nor   always    desirable. 

To  establish  oscillations  we  must  have 
an  inductance  (L)  and  a  capacity  (C), 
and  as  (C)  is  entirely  lacking  when  the 
variometer  is  used  without  a  condenser, 
it  is  evident  that  the  only  tendency 
toward  oscillation  will  be  due  to  the 
exceedingly  small  grid  plate  capacity 
in  the  circuit  and  to  the  equally  small 
distributed  capacity  in  the  windings  of 
the  variometer.  As  with  the  other  in- 
ductance in  Fig.  14,  the  variometer  can 
be  used  only  with  two  or  more  radio 
frequency  stages  where  there  are  at  least 
three  tuning  controls.  Fewer  stages  or 
controls  will  not  give  the  required  selec- 
tivity. 

FIG.  16.  AUTO-TRANSFORMER 
COUPLER.  A  single  circuit  tuner  which 
is  more  selective  than  either  of  the  two 
just  mentioned,  yet  one  which  also  has 
a  pronounced  effect  in  suppressing  self- 
oscillations  is  the  type  shown  in  Fig.  13. 
This  is  simply  a  continuous  single  wind- 
ing, tapped  for  the  aerial  connection  at 
the  point  (N).  This  divides  the  coil  into 
a  virtual  primary  (P)  and  virtual  sec- 
ondary (S)  which  are  electrically  identi- 
cal. This  is  strongly  recommended  where 
there  are  two  or  more  radio  frequency 
stages  or  at  least  three  tuning  controls. 

Absorption  Systems 

GENERAL.      In    the    absorption    sys- 
tems the   excess  energy   tending   to 
set  up  free  oscillations  is  "absorbed"  by 


producing  losses  inductively  in  closed 
auxiliary  circuits.  In  fact,  this  is  the 
method  adopted  in  wave-traps  where 
the  weakened  signals  are  obliterated  by 
the  introduction  of  eddy  current  losses 
or  similar  magnetically  induced  counter- 
currents. 

FIG.  17.  CAPACITY  ABSORPTION. 
Here  we  have  small  auxiliary  coils  (Wl) 
and  (W2)  placed  in  inductive  relation 
to  the  secondary  coils  (LI)  and  (L2)  of 
the  coupler  and  first  radio  frequency 
tuner  respectively.  The  coils  and  the 
fixed  condensers  (Kl)  and  (K2)  form  a 
closed  circuit  in  which  currents  are  in- 
duced by  the  magnetic  coupling  with 
(LI)  and  (L2).  By  varying  the  coupling 
between  the  absorption  circuits  (1)  and 
(2),  and  the  coils  (LI)  and  (L2),  we 
can  absorb  the  excess  energy  which 
tends  to  cause  free  oscillations.  The 
energy  loss  is  due  to  the  idle  currents 
circulating  in  the  small  absorption  cir- 
cuits. From  four  to  eight  turns  of  wire 
are  used  for  (W1-W2)  while  the  capacity 
of  (K1-K2)  is  from  0.00004  mf.  to 
0.00006  mf.  The  distance  between  the 
coils  or  the  coupling  must  be  found  by 
experiment. 

FIG.  18.  RESISTANCE  ABSORP- 
TION. In  this  arrangement  we  have 
the  same  small  absorption  coils,  but  in- 
stead of  using  fixed  condensers  we  have 
the  variable  resistance  (R)  used  for  vary- 
ing the  magnitude  of  the  induced  current. 
As  in  the  case  of  the  former  absorption 
circuit  (Fig.  17),  this  is  very  effective 
and  is  under  close  control.  The  resistance 
of  (R)  is  approximately  200  ohms. 

FIG  19.  SHORTED  TURN  AB- 
SORPTION. A  very  simple,  and  usually 
effective  method  when  carefully  adjusted, 
is  the  "shorted-turn"  or  ring  absorber 
of  Fig.  19.  Here  we  have  the  main 
secondary  coil  (L2)  wound  on  a  tube, 
and  the  absorption  coil  (W-4)  located 
a  short  distance  from  it.  The  coil  (W-4) 
consists  of  a  few  turns  of  insulated  wire 
with  the  ends  twisted  together  and 
soldered  so  as  to  form  a  complete  circuit. 
Excessive  energy  in  the  main  coils 
(L1-L2)  is  absorbed  by  the  inductive 
coupling  with  (W-4),  and  by  careful 
adjustment  of  the  distance  (C),  we  can 
dissipate  just  as  much  energy  as  we  may 
wish.  The  same  effect  can  be  produced 
by  short-circuiting  two  or  three  turns  of 
wire  in  the  coil  (L1-L2),  but  the  control 
is  not  so  accurate.  Coil  (LI)  is  the 
primary. 

FIG.  20.  EDDY  CURRENT  AB- 
SORPTION. It  is  a  well  known  fact 
that  electrical  "eddy"  currents  will  be 
induced  in  metal  parts  when  these  parts 
are  in  the  path  of  the  magnetic  flux,  and 
that  the  energy  loss  in  the  inducing  coil 
is  in  proportion  to  the  eddy  current 
strength.  In  Fig.  20,  we  place  a  disk  of 
sheet  metal  (D)  at  one  of  the  solenoid 
coil  poles  and  at  such  a  distance  that  the 
eddy  currents  are  just  sufficient  to  absorb 
the  excess  energy  in  the  coils  which  tend 
to  cause  oscillation.  This  method  is 
effective  and  is  utilized  in  at  least  one 
make  of  radio  frequency  apparatus.  In 
this  well  known  receiver,  the  metal  back 
plate  of  the  low-loss  condenser  serves 
as  the  plate  (D),  the  coil  being  mounted 
on  the  condenser  and  just  far  enough 
away  from  the  back  plate  to  absorb  the 
excess  oscillations.  Care  must  be  taken 
so  that  the  plate  is  far  enough  away 
prevent  weakening  the  signals  by  ex- 
cessive  absorption. 

FIG.  21.  VARIABLE  PLATE  AB- 
SORPTION. This  is  simply  a  special  and 
convenient  application  of  the  above 
principle  where  a  rotative  plate  (D)  is 
placed   within   the   bore  of  the  coil   and 


The  Magazine  of  the  Hour 

mounted  on  pivots  so  that  it  can  be  easily 
adjusted.  The  nearer  the  plate  is  turned 
at  right  angles  to  the  axis  of  the  coil,  the 
greater  will  be   the  absorption. 

Reversed    Feed-Back    Systems 

FIG.  22.  INDUCTIVE  FEED-BACK. 
In  this  system  the  plate  current  is 
fed  back  inductively  into  the  secondary 
coil  (S)  of  the  tuning  unit  by  means  of 
a  reversed  tickler  coil  (T)  so  that  the 
amplitude  of  the  oscillations  is  con- 
trolled by  the  opposition  of  the  induced 
current.  This  is  exactly  the  opposite 
condition  to  a  tickler  regenerative  sys- 
tem, for  instead  of  the  feed-back  current 
augmenting  the  signal  oscillations  it 
tends  to  suppress  them.  This  is  an  ex- 
ceedingly effective  system  which  has 
been  applied  with  great  success  to  several 
well  known  commercial  tuned  radio  fre- 
quency sets.  When  the  tickler  (T)  is  a 
stationary  coil,  wound  in  fixed  relation 
to  the  secondary  (S)  and  the  primary 
(P),  it  is  controlled  by  the  variable  con- 
denser (C2)  connected  across  the  primary 
of  the  first  radio  frequency  transformer 
(RFT). 

FIG.  23.  RICE  CAPACITATIVE 
FEED-BACK.  This  is  an  exceedingly 
effective  yet  simple  system  of  the  reversed 
feed-back  type  in  which  the  compensat- 
ing plate  current  is  fed  back  into  the 
secondary  coil  (S)  of  the  coupler  by  a 
very  small  variable  condenser  (C2).  The 
plate  current  being  in  phase  with  the 
grid  must  be  led  near  to  the  grid  return 
end  of  the  secondary  coil  (S),  preferably 
at  a  tapped  point  (t)  rather  than  to  the 
extreme  end  of  the  coil.  Very  close  con- 
trol of  the  regeneration  is  had  by  the  use 
of  the  condenser  (C2)  so  that  the  circuit 
can  be  held  closely  to  a  condition  of 
maximum  sensitivity.  The  condenser 
(C2)  should  have  a  maximum  capacity 
of  not  more  than  0.00006  mf.  and  about 
0.00045   is  generally  better. 

FIG.  24.  CAPACITATIVE  FEED- 
BACK TO  AERIAL.  This  is  about  the 
same  thing  as  Fig.  23  in  general  prin- 
ciples, but  instead  of  feeding  back  to 
the  grid  return  end  of  the  secondary  (S), 
we  feed  the  opposing  plate  current  straight 
to  the  antenna  end  of  the  primary  by 
the  small  variable  or  fixed  condenser 
(C2).  This  is  not  quite  so  critical  as 
the  former  method,  and  very  frequently 
a  very  small  fixed  condenser  can  be  em- 
ployed instead  of  the  variable,  thus  doing 
away  with  one  control. 

When  a  fixed  condenser  is  used  its 
value  is  generally  less  than  0.0001  mf., 
but  the  actual  value  must  be  determined 
by  experiment.  In  many  cases  a  neutral- 
izing condenser  will  prove  of  sufficient 
capacity. 

FIG.  25.  COIL  CAPACITY  FEED- 
BACK. This  is  a  simple  and  effective 
system  to  use  when  the  tendency  toward 
self-oscillation  is  not  too  great.  It  con- 
sists of  a  coil  (T)  having  four  or  five  turns 
of  wire  connected  at  one  end  to  the  plate 
of  the  tube.  The  opposite  end  remains 
unconnected.  The  coupling  is  partly 
inductive  and  partly  capacitative,  but 
it  very  often  proves  to  be  an  excellent 
stabilizer  and  needs  no  controls.  We 
can  find  by  experiment  whether  to  place 
it  at  the  end  (a)  or  (b)  of  the  secondary 
coil.  The  distance  between  (T)  and  the 
secondary  should  just  be  sufficient  to 
suppress  the  free  oscillations  and  no  more. 

Balancing  Systems 

FIG.    26.       FEED-BACK    SYSTEM. 
In   this   system   a    part   of   the    plate 
current  is  fed  back  to  a  tap  in  the  second- 
ary   coil    of    the    following    transformer 
(Turn  to  page  18) 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


13 


THE  formula  for 
series  resonance 
or  Wavelength  is 
the  most  commonly 
used  calculation  in 
radio  frequency 
measurements,  and 
forms  the  basis  of  most 
all  construction  and 
experimental  work. 
The  average  experi- 
menter and  con- 
structor,  however,  is 
not  interested  in  its  de- 
rivation nor  the  whys 
and  wherefores;  he  is 
interested  only  in  the 
practical  application  of 
the  formula  to  each  in- 
dividual problem  aris- 
ing in  the  course  of 
work.  Mathematical 
solution  of  each  indi- 
dividua!  application  involves  loss  of  time 
and  some  figuring,  with  the  result  that 
"cut-and-try"  methods  are  generally  re- 
sorted to. 

With  the  accompanying  chart,  instant 
solution  of  the  numerous  applications  of 
the  formula  as  applied  to  broadcast  work 
may  be  obtained.  In  general,  our  capa- 
city ranges  are  from  .00001  to  .001 
microfarads;  and  our  wavelength  ranges 
from  125  to  600  meters,  which  includes 
the  most  used  amateur  bands.  Applying 
these  values  to  two  proper  sized  logarith- 
mic scales  and  working  out  a  few  refer- 
ence problems,  we  may  add  a  third  log 
scale  giving  inductance  values,  and  thus 
graphically  solve  any  problem  that  may 
arise  in  future  times.  Our  inductance 
values  so  obtained  will  cover  a  range  from 
less  than  5  to  over  10,000  microhenries, 
which  will  more  than  cover  the  values  in 
present  day  broadcast  use. 

Using  the  Chart 

r  I  ''HE  use  of  such  a  chart  is  quite  simple, 
-*-  requiring  no  ruler  or  straight  edge,  al- 
although  a  right  angled  marker  of  some 
sort  is  helpful  in  maintaining  the  vertical 
and  horizontal  scales.  In  reading  the 
various  scales,  it  is  well  to  interpolate 
between  captioned  lines,  since  the  various 
lines  in  between  are  necessarily  of  vary- 
ing spacing,  owing  to  the  exigencies  of 
drafting  and  reproduction.  At  the  inter- 
section of  any  three  lines  of  the  scales, 
we  have  an  individual  solution  of  the  re- 
sonance problem.  Thus,  if  any  two 
values  are  known,  we  may  read  the  third 
unknown  from  the  third  scale.  As  an 
example,  assume  we  have  a  .0005  mfd. 
condenser  connected  across  a  coil  of 
unknown  value,  and  the  circuit  thus 
formed  is  found  to  tune  to  a  wavelength 
of  600  meters.  Following  the  .0005  mfd. 
capacity  line  vertically  until  it  crosses 
the  600  meter  line,  we  then  read  diagon- 
ally on  the  inductance  scale  where  we 
find  approximately  204  microhenries, 
which  we  may  assume  to  be  the  induc- 
tance of  the  coil.  Likewise,  we  may  de- 
termine wavelength  if  the  capacity  and 
inductance  are  known;  and  capacity,  if 
the  inductance  and  wavelength  are 
known.  Such  inductance  determinations 
will  be  the  apparent  inductance,  since  we 


{[Practical  Application  of  the 
Series   Resonance   Formula 


Solving  Inductance, 
Capacity,  and  Wave- 
length Problems 


By  E.  E.  GRIFFIN 


have  neglected  the  distributed  capacity 
of  the  coil  itself. 

The  Honeycomb  Coil 

\  S  another  example,  let  us  take  the 
-'*-  case  of  the  well  known  honeycomb 
coil.  The  50  turn  coil  is  listed  by  the 
manufacturers  as  having  a  pure  induct- 
ance of  149  microhenries,  a  distributed 
capacity  of  .000031  mfd.  and  a  natural 
period  or  wavelength  of  128  meters. 
Here  we  have  all  three  values  given,  and 
we  may  check  against  our  chart.  (The 
150  microhenrie  line  gives  approximately 
128H  meters  at  .000031  mfd.)  Now 
assume  that  we  connect  across  this  50 
turn  coil  a  condenser  having  a  maximum 
capacity  of  .0006  mfd.,  and  we  desire  to 
know  the  wavelength  of  the  circuit  thus 
formed.  Our  inductance  is  known  to 
be  149  mh.  and  our  total  circuit  capacity 
will  be  the  distributed  capacity  of  the 
coil  plus  that  of  the  condenser,  a  total  of 
.000631.  Finding  the  intersection  of 
these  two  values  on  our  chart,  we  read 
horizontally  on  the  wavelength  scale 
and  find  550  meters,  the  wavelength  of 
our  circuit. 

If  the  condenser  be  a  variable  one  with 
a  known  minimum  capacity  of  .00004 
mfd.,  the  shortest  wavelength  to  which 
this  circuit  would  be  capable  of  tuning 
would  be  195  meters,  our  minimum 
circuit  capacity  in  this  case  being  .00004 
plus  .000031,  or  .000071  microfarads.  In 
all  cases  of  series  resonance  where  we 
have  a  coil  and  condenser,  the  distributed 
capacity  of  the  coil  is  added  numerically 
to  the  capacity  of  the  condenser. 

The  foregoing  examples  are  given 
simply  in  explanation  of  the  use  and 
application  of  the  chart,  and  it  is  believed 
they  are  sufficient  for  proper  understand- 
ing in  its  many-fold  uses.  To  the  ad- 
vanced broadcast  fan,  no  more  explana- 
tion will  be  needed,  but  for  the  amateur 
in  the  formulation  of  transmitting  cir- 
cuits where  larger  capacities  than  those 
given  are  used,  further  application  of  the 
chart   will   be   discussed. 

For  Larger  Capacities 

THE  chart  may  also  be  used  for  larger 
capacities  than  those  given  by  multi- 
plication and  division  of  the  inductance 


and  capacity  values. 
Since  the  wavelength 
of  a  circuit  is  propor- 
tional to  the  product 
of  the  inductance  and 
capacity,  we  may 
multiply  one  scale  by 
a  certain  number, 
dividing  the  other 
scale  by  the  same  num- 
ber, and  our  solution  on 
the  chart  will  still  hold. 
As  an  example,  as- 
sume that  we  have  a 
condenserof  .0012  mfd. 
capacity  and  desire  a 
wavelength  of  200 
meters.  The  chart 
does  not  give  .0012 
mfd.,  so  we  use  the 
value  .00012.  The  in- 
tersection of  this  line 
with  the  200  meter  line 
gives  us  an  inductance  of  95  microhenries. 
Now  our  actual  capacity  is  ten  times  the 
chart  value,  so  we  must  divide  the  in- 
ductance value  by  ten,  which  gives  an 
answer  of  9.5  microhenries.  Thus  for  a 
wavelength  of  200  meters,  using  a  con- 
denser of  .0012  capacity,  we  will  require 
an  inductance  of  9.5  mh.  Just  so,  if 
our  inductance  and  wavelength  are 
known,  we  may  determine  the  required 
capacity  by  using  the  reverse  operation. 
For  calculations  on  the  90  to  80  meter 
band,  the  chart  may  be  extended  beyond 
the  present  limits,  which  are  necessary 
for  the  size  of  a  printed  page.  Better 
and  more  rapid,  simply  divide  all  scales 
as  given  by  2.  Thus,  80  meters  wave- 
length would  require  a  capacity  of  .0001 
mfd.  and  an  inductance  of  18  mh.;  which 
is  represented  on  the  chart  in  the  double 
values  of  160  meters,  .0002  mfd  and  36 
mh.  Likewise,  using  the  same  value  of 
inductance,  for  90  meters  we  would  re- 
quire a  capacity  of  .000125;  which  values 
on  the  chart  would  be  represented  by  180 
meters,  36  mh.  and  .00025  mfd. 

Such  a  chart  is  a  valuable  addition  to 
any  reference  or  notebook,  and  the  experi- 
menter and  constructor  are  advised  to 
cut  out  the  page  and  place  it  by  for 
future  use.  It  is  also  an  indispensable 
time  and  labor-saver  for  the  user  of  a 
wavemeter  or  oscillator,  enabling  rapid 
measurements  in  all  radio  frequency 
work. 


Many  an  experimenter  has  often  wanted 
a  means  of  determining  the  constants  of 
coils  or  condensers.  The  foregoing  article 
by  Mr.  Griffin,  together  with  the  chart  on 
the  following  page,  should  appeal  to  every 
radio  fan  with  curiosity  along  the  lines  of 
inductance  and  capacity. 

In  the  event  you  do  not  desire  to  mutilate 
your  September  issue  of  RADIO  AGE, 
send  thirty  cents  in  stamps  to  our  office 
and  we  will  supply  you  with  another  copy 
of  the  September  number  from  which  you 
may  clip  the  chart  and  save  for  future 
reference. 

Mr.  Griffin  is  now  making  intensive  ex- 
periments in  wavelength  formulae  and  other 
interesting  problems.  His  work  will  be  re- 
corded in  an  early  issue  of  RA  DIO  A  GE. 


Chart  for  Instant  Solution  of  Wavelength  Formula  on  Next  Page 


14 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


WAVELENGTH-  METERS 


INDUCTANCE-  MICROHENRIES 


Here  is  the  chart  explained  in  the  article  on  the  preceding  page,  by  which  applications  of  the  wavelength  formula  as  applied  to  broadcast 
work  may  be  solved  with  little  trouble.     In  reading   the   scales,   it   will   be   advisible   to  interpolate  between  captioned  lines,  since  the 

various  lines  in  between  are  necessarily  of  varying  spacing. 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


15 


"Going  Down'  to  Lower  Waves 


<[  Crowded  Wave  Bands 

May  Force  Search 

for  New  Radio 

Channels 


HOW  different  things  might  be  if 
they  wasn't  as  they  is  "  sang  one 
of  the  actors  in  a  comic  opera 
that   was   popular  a   generation   ago. 

That's  the  way  it  is  with  radio.  If 
the  whole  range  of  wavelengths  that 
could  be  used  for  transmission  had  been 
known  ten  years  ago,  today's  problems 
would  be  less  complicated.  As  it  is,  the 
wavelengths  from  600  meters  up  are 
occupied  by  government  and  commercial 
stations  and  the  wavelengths  from  200 
meters  down  are  looked  upon  by  ama- 
teurs as  their  territory  by  right  of  dis- 
covery. This  leaves  a  band  of  400  meters 
available  for  broadcasting. 

Broadcasting  stations  are  increasing 
so  rapidly,  however,  that  they  cannot  all 
squeeze  into  this  band.  Moreover, 
they  are  increasing  power  to  such  an 
extent  that  it  is  hard  to  shut  them  out, 
even  with  highly  selective  receivers. 

It  looks  as  though  broadcasting  wave- 
lengths were  going  down.  If  they  try 
to  push  the  upper  limit  higher,  broad- 
casters will  have  to  buck  the  well-en- 
trenched commercial  companies,  which 
have  large  investments  in  stations  and 
plenty  of  ammunition  for  fighting  inter- 
ference. It  will  be  much  safer  to  poach 
on  the  amateurs'  preserve,  below  200 
meters.  It  is  predicted  that  in  the  near 
future  broadcasting  wavelengths  will  go 
as  low  as  150  meters.  It  may  not  dis- 
turb the  amateur  very  much  anyhow, 
for  the  up-to-date  brass  pounders  are 
already  working  down  below  100  meters. 

Some  of  the  Problems 

COME  of  the  set  manufacturers  are 
^  worried,  because  practically  all  broad- 
cast receivers  have  been  designed  for 
waves  between  200  and  600  meters. 

Some  of  the  radio  users  will  be  worried, 
too,  if  stations  open  up  that  they  cannot 
hear,  before  the  final  instalments  are 
paid  on  their  expensive  sets. 

However,  it  is  not  time  yet  to  junk 
receivers,  even  though  they  are  not  built 
to  receive  the  low  waves  that  come 
rippling  along  at  the  rate  of  two  million 
per  second.  The  wavelength  that  a 
receiver  will  bring  in  at  any  given  mo- 
ment depends  upon  the  inductance  and 
capacity  in  its  tuned  circuits.  Induc- 
tance and  capacity  can  be  added  to  or 
subtracted  from  the  circuits.  Sometimes 
it  is  possible  to  change  the  tuning  range 
of  a  receiver  at  small  expense  and  without 
any   danger   of   injuring   the   apparatus. 

The  wavelength  of  a  circuit  is  the 
product  of  its  inductance  and  its  capacity. 
Inductance  is  expressed  in  centimeters 
and  capacity  in  microfarads.  If  the  pro- 
duct is  large  when  these  two  are  multi- 
plied together,   the  wavelength   is  long; 


A  fixed  condenser  placed  in  series  with  the 

antenna  of  a  single-circuit  receiver,  to  reach 

down  to  the  lower  wavelengths. 


By  ARMSTRONG  PERRY 


if  the  product  is  smaller,  the  wavelength 
is  shorter.  Nothing  complicated  about 
that.  The  inductance  is  mainly  in  the 
coils  and  the  capacity  is  largely  in  the 
condensers.  More  turns  in  the  coils  or 
more  plates  in  the  condensers  increase 
the  wavelength.  Less  turns  or  less  plates 
mean  lower  wavelengths.  Sometimes 
there  are  other  factors,  such  as  wider 
spacing  between  condenser  plates,  but 
the  principle  is  the  same.  The  tuning 
devices  in  the  receiver  are  devices  for 
increasing  and  decreasing  the  induc- 
tance and  capacity. 

It  is  possible  for  even  the  novice  to 
find  out  roughly  how  much  inductance 
and  capacity  there  are  in  all  his  circuits. 
In  the  antenna,  however,  there  is  a  value 
of  capacity  that  is  unknown  as  a  rule, 
for  the  antenna  and  the  earth  form  an 
unmeasured  condenser.  Radio  text- 
books such  as  "The  Principles  Underly- 
ing Radio  Communication,"  used  by  the 
United  States  Signal  Corps  and  sold  at 
one  dollar  a  copy  by  the  Superintendent 
of  Documents,  Government  Printing 
Office,  Washington,  D.  C,  contain 
tables  simple  enough  to  be  understood 
by  the  average  mind.  They  show  that  a 
wavelength  of  300  meters  means  a  fre- 
quency of  1,000,000  per  second.  When 
one  million  waves  per  second  oscillate  in 
a  circuit,  the  length  of  each  wave  is  300 
meters. 

It  is  impossible  to  get  the  full  benefit 
of  300-meter  waves  in  a  400-meter  cir- 
cuit. A  nearby  and  powerful  broad- 
casting station  might  force  its  waves 
through  your  set  and  into  your  phones 


C  How  You  Can  Change 

Tuning  Range  of 

Your  Set  Sans 

Trouble 


or  loud  speaker  even  when  you  are  not 
tuned  to  it,  but  to  bring  in  300-meter 
waves  from  a  distant  station  you  must 
tune  your  circuit  to  300  meters.  This 
means  that  the  product,  when  the  capac- 
ity in  the  circuit  is  multiplied  by  the 
inductance,  is  25.33,  according  to  the 
table. 

Now,  this  product,  25.33,  may  be  ob- 
tained in  several  different  ways.  If  your 
inductance  is  represented  by  5,  capacity 
of  approximately  5.07  would  give  the 
circuit  the  proper  wavelength.  If  your 
inductance  were  1,  then  you  would  need 
capacity  of  25.33. 

Value  of  Inductance 

HPHE  value  of  the  inductance  in  a  cir- 
■*-  cuit  may  be  hard  to  find,  for  the  size 
of  the  wire,  the  diameter  of  the  coil,  the 
number  of  turns  and  the  space  between 
them  all  have  their  effect.  The  instru- 
ments needed  for  measuring  inductance 
are  found  only  in  the  laboratories  as  a 
rule.  The  capacity  of  a  condenser  is 
easy  to  find,  usually,  for  it  is  marked  on 
the  apparatus.  Also  you  can  easily  find 
the  wavelengths  of  the  stations  you  can 
hear,  for  they  are  published  in  the 
newspapers.  The  indicated  capacity  of 
the  condenser  is  its  maximum,  so  if  you 
turn  the  dial  to  its  maximum  position, 
or  near  it,  and  use  your  maximum  induc- 
tance, and  note  the  wavelength  of  the 
station  you  bring  in  at  that  setting  of  the 
dials,  you  can  figure  out  approximately 
what  inductance  you  have  in  the  tuned 
circuit. 

For  example,  at  maximum  setting,  you 
bring  in  a  600-meter  station.  Your 
condenser  is  marked  .0005.  The  table 
shows  that  the  product  of  inductance 
and  capacity  in  a  circuit  tuned  to  600 
meters  is  101.4.  The  value  of  induc- 
tance, then,  must  be  101.4  divided  by 
.0005,  which  is  202,800. 

The  ability  to  estimate,  at  least  rough- 
ly, the  capacity  and  inductance  in  a  tuned 
circuit,  is  very  useful  when  you  want  to 
change  the  tuning  range  of  a  receiver, 
either  temporarily  or  permanently.  How- 
ever, it  is  possible  for  a  novice  to  experi- 
ment with  some  hope  of  success,  even 
though  he  does  not  study  the  matter 
deeply. 

Suppose  you  want  to  get  down  to  the 
210  meter  wavelength  and  your  receiver 
tunes  at  present  no  lower  than  300 
meters.  One  simple  principle  helps 
materially;  namely,  the  effective  capacity 
of  condensers  connected  in  series  is  less 
than  the  capacity  of  any  one  of  them. 
Since  the  antenna  and  the  earth  form  one 
condenser  in  the  antenna  circuit,  the 
capacity  of  that  circuit  can  be  reduced 
by  connecting  another  condenser  in 
series.      This    cannot    be    continued    in- 


16 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


In  the  diagram  shown  above  the  cutting  down  of  wavelength  of  the  receiver  is  accomp- 
lished by  reducing  the  number  of  turns  in  the  inductance.  At  No.  1  you  have  least  number 
of  turns  and  hence  lowest  wavelength.  At  No.  2  the  wavelength  is  higher  and  at  No.  3  it 
is  at  a  maximum.  For  those  who  prefer  low  loss,  the  inductance  can  be  made  on  separate 
forms  and  inserted  in  the  set  when  it  is  desired  to  go  down.  The  plate  inductance  is  shown 
as  variometer,  but  it  may  be  any  form  of  an  inductance.  By  the  method  shown  above,  if  the 
very  short  waves  are  desired  it  will  by  necessary  to  put  a  small  condenser  something  like  a 
.000012  in  series  with  the  antenna,  but  for  ordinary  low  wavelengths  [on  which  phones  can 
be  found,  the  scheme  as  outlined  will  work. 


definitely,  because  if  several  condensers 
are  used  the  transfer  of  energy  is  reduced 
so  greatly  that  the  signals  cannot  be 
heard.  A  thirty-five  cent  fixed^condenser, 
connected  in  series  with  the  antenna, 
may  be  all  that  is  necessary  to  bring  a 
single-circuit  receiver  down  to  the  lower 
wavelengths. 

In  the  other  circuits,  the  problem  is 
harder.  Theoretically,  at  least,  the 
variable  condensers  may  have  zero 
capacity  at  the  minimum  setting.  Add- 
ing another  condenser  will  not,  of  course, 
reduce  the  minimum  capacity  below 
zero.  If  there  are  capacity  effects  in  the 
circuit  caused  by  something  other  than 
condensers,  however,  the  addition  of 
another  condenser  in  series  may  lower 
the  tuning  range  of  the  circuit.  In  most 
cases  it  will  be  found  necessary  to  re- 
duce the  effective  inductance  of  the  cir- 
cuit. Sometimes  this  can  be  done  by 
tapping  a  fixed  inductance,  inserting  a 
switch  and  making  it  a  variable  induc- 
tance. 

Shortening    the    Aerial 

"T>  EDUCING  the  length  of  the  an- 
J-  *-  tenna  tends  to  lower  the  wave- 
length. It  also  reduces  the  amount  of 
energy  picked  up  by  the  antenna,  but 
that  may  not  be  serious. 

Manufacturers  may  help  users  of  their 
sets  by  providing  instructions  for  making 
the  alterations  or  additions  necessary  to 
reach  the  new  wavelengths.  Customers 
should  be  reasonable  in  their  demands, 
for  it  is  a  very  difficult  matter  to  design 
a  receiver  that  is  highly  efficient  over  a 
broad  band  of  wavelengths.  It  is  a 
still  more  difficult  matter  to  alter  a  set, 
carefully  designed  for  high  efficiency 
over  a  specified  range,  so  as  to  increase 


its    tuning    range    without    lowering    its 
efficiency. 

Paul  Bunyan,  the  mythological  lum- 
ber-jack whose  exploits  have  been  pub- 
lished recently,  understood  the  desira- 
bility of  specialization  and  developed 
side-hill  chickens  and  a  dog,  half  dasch- 
und  and  half  greyhound,  that  never  was 
tired  because  with  its  long  legs  behind 
and  its  short  ones  in  front  it  was  always 
running  down  hill.  Perhaps  the  amateur 
radio  constructors  will  do  better  if  they 
build    receivers    for    the    shorter    broad- 


casting waves  instead  of  trying  to  make 
one  receiver  cover  the  whole  range. 

The  exodus  to  the  shorter  waves  will 
not  be  as  rapid  as  one  might  be  led  to 
imagine.  For  one  thing,  there  are  un- 
doubtedly many  stations  at  present  in 
operation  who  will  succumb  to  the 
business  disease,  Overhead  Expense,  and 
with  a  high  rate  of  mortality  (such  as 
has  been  the  case  since  the  beginning  of 
the  broadcast  craze)  the  number  of  sta- 
tions will  probably  be  kept  at  a  crowded 
but  nevertheless  fairly  comfortable  level. 

Nor  will  the  search  for  new  channels 
at  once  invalidate  the  present  receivers. 
These  are  as  a  rule  excellent  sets  and 
with  greater  attention  being  paid  to 
selectivity  the  crowded  conditions  of  the 
air  lanes  need  not  occasion  any  great 
degree  of  anxiety  on  the  part  of  the  radio 
fans. 

Of  course,  for  a  "broad"  set  even  five 
stations  would  crowd  the  ether,  but  with 
manufacturers  paying  greater  heed  to 
requirements  of  selectivity  for  owners 
in  the  congested  areas,  the  multiplicity 
of  stations  should  not  worry  any  one. 
Naturally  a  fan  cannot  expect  to  hear 
every  one  of  the  five  hundred  odd  broad- 
casting stations  in  the  United  States. 
Many  stations,  separated  by  many  hun- 
dred miles,  are  working  on  the  same  wave 
band  and  no  receiver  yet  designed  will 
separate  the  two.  In  those  cases  the 
listener  must  be  satisfied  with  the  nearest 
station  and  let  the  residents  farther  away 
from  him  take  advantage  of  the  station 
he  seeks  but  cannot  hear. 

While  it  would  be  foolhardy  to  expect 
no  change  in  the  industry  or  the  radio 
situation  (for  no  change  would  denote 
stagnation),  nevertheless  any  changes 
that  may  come  will  be  of  a  gradual 
nature  and  not  calculated  to  throw  the 
game  into  a  seething  chaos  in  which 
millions  of  people  would  be  involved. 

The  ideas  expressed  in  this  article  are 
more  applicable  to  the  older-style  sets 
than  they  are  to  the  type  that  now  tune 
from  220  to  550. 


Fig.  2.  In  the  inductively  coupled  circuit  shown  here,  to  reduce  the  wavelength  it  is 
necessary  to  cut  out  primary  as  well  as  secondary  inductance.  The  symbols  are  the  same 
as  in  Fig.  1.  Of  course  the  plate  inductance  should  be  varied;  that  is,  cut  down,  as  the 
experimenter  goes  farther  down  on  the  wavelength  scale.  For  best  results  the  primaries 
and  secondaries  should  be  wound  on  separate  forms  and  inserted  for  the  desired  wave- 
lengths. Those  interested  further  in  short  wave  work  may  refer  to  the  Pickups  and  Hook- 
ups Section  this  month  where  a  short  wave  receiver  is  described. 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


17 


TUNING  and  Regeneration  by 
Separate  Controls 


Best  Methods 

to  Minimize 

The  Detuning 

Effect  of 

Tickler 

By  BRAINARD  FOOTE 


THEORETICALLY,  the  adjust- 
ments for  tuning  and  regeneration 
should  be  completely  independent. 
Practically,  however,  these  two  essential 
controls  interfere  with  each  other  more 
or  less.  Hence,  when  we  attempt  to 
tune  in  a  very  faint  station,  we  find  it 
necessary  to  "fiddle"  with  the  tuning 
knob  every  time  we  approach  more  or 
less  closely  to  the  point  of  oscillation 
with  the  tickler. 

If  we  observe  carefully,  we  shall  dis- 
cover that  a  movement  of  the  tickler  coil 
such  that  the  tube  is  brought  nearer  to 
the  oscillation  point  calls  for  a  decrease 
in  the  setting  of  the  tuning  condenser. 
The  fact  that  the  tickler  adjustment 
DOES  affect  the  tuning  may  be  readily 
verified  by  noting  that  any  motion  of  the 
tickler  while  the  tube  is  oscillating 
changes  the  pitch  of  the  whistle. 

In  an  ideal  set,  the  tube  would  go  into 
and  even  past  oscillation  by  the  tickler 
adjustment,  without  any  change  in  the 
wavelength.  There  are  two  outstanding 
causes  for  the  detuning  effect  of  the 
tickler  coil.  The  first  of  these,  and  most 
serious,  is  due  to  the  "mutual  induc- 
tance" between  the  tickler  coil  T  and  the 
secondary  coil  S,  Fig.  1.  When  the 
tickler  is  moved  nearer  to  the  secondary, 
or  turned  to  have  a  greater  inductive 
effect  upon  it,  the  mutual  inductance  is 
added  to  the  natural  inductance  of  the 
secondary.  The  result  is  to  INCREASE 
the  effective  inductance  of  the  secondary 
coil.  This,  in  turn,  requires  a  RE- 
DUCED capacity  in  the  condenser  C-l, 
to  maintain  the  same  wavelength. 

Capacity  Effect 

'  |  ''HE  small  condenser  caused  by  the 
-'-  metal  in  the  tickler  and  that  in  the 
secondary  coils  acts  in  shunt  to  the 
tuning  condenser  and  increases  in  capac- 
ity as  the  tickler  is  moved  closer.  This 
effect  is  most  pronounced  on  short  wave- 
lengths, and  to  reduce  it,  the  tickler  coil 
should  always  be  placed  at  the  filament 
end  F  of  the  secondary,  instead  of  at  the 
Grid  end  G,  as  shown.  The  location 
illustrated  is  very  common,  however, 
even  though  it  does  cause  detuning  by 


Fig.   1. — In    the   above   circuit   arrangement,   the  tickler  detunes  the  secondary  by  the 

mutual  inductance  and  capacity  effects.     These  can  be  reduced  by  using  fewer  turns  and 

smaller  wire  on  the  tickler. 


capacity  on  the  higher  frequencies 
(shorter  waves). 

The  mutual  inductance  effect  is  very 
marked.  In  the  case  of  a  loud  local 
station,  it  is  interesting  to  reverse  the 
tickler  and  note  how  greatly  the  effective 
inductance  of  the  secondary  is  RE- 
DUCED in  this  manner.  It  then 
becomes  necessary  to  increase  the  capac- 
ity of  the  tuning  condenser,  to  compen- 
sate for  the  reduced  secondary  induc- 
tance. 

In  any  existing  set  connected  as  in 
Fig.  1  it  is  possible  to  minimize  the 
detuning  effect  of  the  tickler  coil  in  three 
ways : — 

1.  Using     as     few     tickler     turns     as 

possible. 

2.  Using  small  wire  in  the  tickler  coil. 

3.  Making   tube   conditions   favorable 

to  oscillation. 
Many  sets  oscillate  readily  with  the 
tickler  almost  at  zero  coupling.  Usually 
15  to  20  turns  on  the  tickler  are  sufficient. 
Small  wire  reduces  the  capacity  effect 
and  does  not  interfere  with  the  efficiency 
of  reception  in  any  way.  Many  use 
wire  as  small  as  No.  30  or  No.  34.  To 
facilitate  regeneration,  the  tube  should, 
of   course,    be   a    good   one.     A    by-pass 


condenser  of  .002  MFDS.  is  necessary, 
also.  The  grid  leak  should  not  be  too 
low  in  resistance.  A  leak  of  3  to  5 
megohms  is  desirable  for  DX  reception, 
although  it  is  difficult  to  find  such  a  leak 
that  functions  quietly.  The  plate  volt- 
age, in  the  case  of  almost  all  hard  tubes, 
should  be  about  45. 

Another  System 

T^IG.  2  shows  the  old  Weagant  re-ar- 
*-  rangement  that  eliminates  in  a  most 
satisfying  degree  the  tickler's  detuning 
effect.  In  place  of  the  movable  tickler, 
a  fixed  tickler  is  adopted.  The  plate 
current  from  the  "B"  battery  does  NOT 
flow  though  this  coil,  as  in  Fig.  1,  but  is 
supplied  to  the  tube  by  what  is  known 
as  the  "shunt  feed"  system.  The  audio 
frequency  plate  circuit  may  be  followed 
from  the  filament  through  the  "B"  bat- 
tery, the  phones,  the  radio  frequency 
choke  coil  X  to  the  plate.  Radio  fre- 
quency impulses  that  provide  the  regen- 
eration, pass  through  the  variable  con- 
denser C-2,  the  tickler  T  and  to  the  fila- 
ment at  F.  The  coil  X  does  not  allow 
the  R.  F.  impulses  to  traverse  the  audio 
portion  of  the  circuit. 

The  insert  gives  a  cross-sectional  idea 


Fig.  2. — Here  the  plate  circuit   is   "split"   (a  la    Weagant)   into   its   radio  and   audio 

frequency   components.      The  tickler  coil   is  fixed   and   regeneration    is   controlled   by 

varying  the  strength  of  the  feedback  current  with  condenser  C-2. 


18 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


of  the  three-coil  unit.  The  secondary 
coil  S  is  wound  on  a  length  of  dried  and 
treated  cardboard  tubing  about  4  inches 
in  diameter.  For  utmost  efficiency,  this 
coil  should  be  wound  with  No.  16  to  No. 
20  wire,  spaced  by  the  width  of  one  wire 
and  having  50  to  65  turns,  depending 
upon  the  nature  of  the  tuning  condenser 
C-l.  The  primary  P  consists  of  5  to  10 
turns  of  the  same  size  wire,  wound  on  a 
tubing  slightly  larger  than  coil  S.  It  is 
simple  enough  to  place  three  or  four 
wraps  of  paraffined  paper  over  the  end 
of  coil  S  and  wind  P  upon  it. 

Directly  inside,  on  a  slightly  smaller 
tubing,  the  tickler  T  is  placed.  This 
consists  of  about  15  close- wound  turns 
of  any  small  size  wire,  No.  26  to  No.  34. 
In  this  fashion,  the  coupling  between  the 
three  coils  is  made  close  and  both  coils 
are  located  at  the  FILAMENT  end  of 
the  secondary.  Condenser  C-2  may  be 
of  about  .00035  MFDS.  capacity.  Choke 
coil  X  may  consist  of  100  turns  of  very 
fine  wire,  space-wound  on  a  cardboard 
tube  about  1  inch  in  diameter.  This  is 
not  absolutely  essential  to  the  operation 
of  the  circuit,  inasmuch  as  the  head- 
phones act  as  an  R.  F.  choke  fairly  well. 
(No  by-pass  condenser  is  used).  There 
is  some  body  capacity  effect  introduced 
when  omitting  the  coil  X,  not  upon  the 
tuning,  but  upon  the  setting  of  condenser 
C-2.  A  circuit  of  this  character  goes  in 
and  out  of  oscillation  smoothly  and  with 
perfect  control  by  C-2.  The  point  of 
oscillation   may   be   more  or  less  closely 


Fig.  3. — A  simple  modification  of  the  circuit  of  Fig.  2  for  those  who  wish   to  experiment 
with  an  independent  form  of  tickler  control. 


approached  without  necessitating  any 
change  in  the  dial  setting  of  C-l.  As  a 
result,  tuning  dial  readings  may  be 
noted  with  extreme  accuracy  and  even 
on  the  shortest  wavelengths,  a  dial  read- 
ing of  9 }4,  let's  say,  will  always  be  9% 
for  a  given  station. 

Experimental  Coil 

A  SIMPLER  arrangement  of  the  same 
hook-up  appears  in  Fig.  3.  Here 
a  single  coil,  having  one  tap,  is  employed. 
The  coil  is  4  inches  in  diameter,  being 
close-wound  and  having  55  turns  in  all, 
or  space-wound  and  having  about  65 
turns  in  all.  The  filament  tap  F  is  taken 
at  10  turns  from  one  end,  with  the  grid 
connection  at  the  other  end.  Thus  F 
to    G    comprises    the    secondary    and    is 


tuned  by  a  .0005  MFDS.  variable  con- 
denser. P  to  F  comprises  the  primary 
and  also  the  tickler.  C-2  is  a  .0005 
MFDS.  instrument  also.  The  phones 
are  placed  to  act  as  coil  X  in  the  previous 
discussion.  This  is  a  sure  and  simple 
circuit  for  experimentation — one  in 
which  tuning  and  regeneration  are  inde- 
pendent of  each  other. 

The  most  successful  long  distance 
receiving  set  is  one  where  the  tuning  dial 
may  be  carefully  adjusted  by  one  hand 
and  the  regeneration  dial  by  the  other 
with  complete  independence  of  action. 
No  change  in  the  tickler,  made  to  add 
the  final  bit  of  sensitivity  before  the 
faint  call  letters  are  distinguishable, 
upsets  the  wavelength  adjustment  already 
made. 


Thirty-one  Ways  To  Prevent  Oscillations 


through  a  small  variable  condenser  (C3). 
This  is  a  critical  adjustment  for  every 
wavelength  and  therefore  demands  a 
control  dial  on  front  of  the  panel,  but 
it  is  very  effective  and  adds  to  the 
signal  strength  and  selectivity  of  the 
circuit. 

FIG.  27.  FERRAND  SYSTEM.  The 
Ferrand  system  not  only  suppresses  free 
oscillations  but  it  also  broadens  the 
tuning  so  that  as  many  as  six  tuned 
stages  of  radio  frequency  amplification 
are  possible  without  excessively  sharp 
tuning.  By  ordinary  methods  it  is  diffi- 
cult to  handle  two  tuned  radio  stages, 
let  alone  five  or  six.  A  resistance  (R)  of 
from  5,000  to  10,000  ohms  is  connected 
in  series  with  a  fixed  condenser  (K)  so 
that  a  limited  amount  of  current  is  fed 
back  into  the  grid  circuit.  The  resistance 
damps  down  any  tendency  to  over- 
oscillate  while  the  condenser  (K)  stops 
the  plate  current  and  prevents  it  from 
putting  a  positive  bias  on  the  grid.  The 
value  of  (K)  is  not  critical  and  will 
average  about  0.0001   mf. 

FIG.  28.  ROBERTS  SYSTEM.  The 
Roberts  Reflex  system  employs  a  split 
primary  coil  which  feeds  back  to  the 
grid  of  the  first  tube  (Tl)  through  the 
small  variable  condenser  (0.000045  mf.) 
marked  (Kl).  Plate  current  passes 
through  the  primary  half  (b)  and  the 
grid  current  is  induced  in  the  half  (a). 
The  total  number  of  turns  in  the  primary 
is  10,  with  five  turns  in  each  half.  The 
secondary    (S)    is    wound    in    the    usual 


(Continued  from  page  12) 

inductive  relation  to  the  primary,  and 
the  detector  tickler  coil  (TICK)  is  added 
for  obtaining  regeneration  in  the  detector 
tube  circuit  (T2);  The  values  of  the 
bypass  condensers  are  given  on  the  draw- 
ing. 

This  is  a  very  effective  means  of  stabil- 
izing a  reflex  circuit  where  an  audio  fre- 
quency transformer  (AFT)  is  included 
in  the  grid  return  line.  Further  stabiliza- 
tion is  obtained  by  the  use  of  a  "C" 
battery. 

FIG.  29.  BRIDGE  BALANCE.  In 
this  circuit,  the  grid  is  balanced  by  means 
of  two  small  variable  condensers  (K1-K2) 
the  (-A)  line  being  connected  between 
them.  When  once  adjusted,  the  con- 
densers (Kl)  and  (K2)  need  no  further 
attention  on  any  wavelength,  and  the 
main  tuning  condenser  is  in  full  control 
of  the  tuning  operations.  It  is  effective 
but  somewhat  complicated  and  difficult 
to     adjust. 

Grid  Neutralization 

FIG.  30.  OLD  TYPE  NEUTRO- 
DYNE.  In  this  popular  circuit,  the 
grid-plate  capacity  was  formerly  neutral- 
ized by  the  very  small  neutralizing  con- 
densers (NC)  connected  between  the 
grids  of  the  two  radio  frequency  tubes 
(T1-T2)  and  the  detector  tube  (T3). 
This  was  later  succeeded  by  an  altera- 
tion in  the  connection  of  the  neutralizing 
condensers  (NC)  as  will  be  shown  in  the 
following    illustration. 


FIG.  31.  MODERN  NEUTRODYNE 
SYSTEM.  Instead  of  connecting  the 
neutralizing  condensers  directly  from 
grid  to  grid  as  before,  one  end  was  con- 
nected to  a  tap  point  (N)  on  the  succeed- 
ding  radio  frequency  transformer  second- 
ary. This  gave  better  results  and  it 
was  far  simpler  to  make  the  neutralizing 
adjustments.  The  condensers  (NC)  are 
adjustable  and  have  an  exceedingly 
small  capacity,  a  capacity  approximately 
of  the  same  dimensions  as  the  grid-plate 
capacity.  Once  adjusted,  they  need  no 
further  attention  until  the  tube  wears 
down  or  until  the  tube  is  replaced  by 
a   new   one. 

This  is  very  effective,  but  the  adjust- 
ment should  not  be  made  with  the  in- 
tention of  getting  full  neutralization. 
Regeneration  must  not  be  entirely  sup- 
pressed, as  this  destroys  the  sensitivity 
of   the   receiver. 

COILS  WITH  SELF-CONTAINED 
FIELDS.  Excessive  regeneration  caused 
by  stray  magnetic  fields  has  been  largely 
eliminated  by  circular  coils,  thus  reducing 
the  duty  on  the  stabilizer.  However- 
this  does  not  eliminate  the  capacity  feed, 
back  between  stages  nor  does  it  affect 
the  grid-plate  feed-back  through  the  tube; 
hence  some  stabilization  is  generally 
necessary  to  take  care  of  these  effects. 
Owing  to  the  fact  that  such  coils  are  not 
affected  by  external  magnetic  fields, 
they  are  more  selective  than  other  types 
and  pick  up  neither  external  waves  nor 
internal    strays. 


RADIO  AGE  for  September,  1925 


|    KEY 


HETBP 

OR 

GALVANOMETER 


Fig.  I 

showing   how   current  is 
produced  by    induction 


How  Sound  Travels 

from  Microphone 

to  Headphones 

is  Explained 

By  Expert 

JUST  how  the  radio  program  is  car- 
ried through  the  ether  to  the 
millions  of  listeners  is  somewhat  of 
a  mystery  to  many.  There  are  some  lis- 
teners who  do  not  care,  th  r  interest 
being  centered  only  upon  ho  they  can 
hear  these  programs,  what  ind  of  a 
receiver  is  best  for  the  purpo  and  how 
much  it  will  cost  to  install  sucl.  receiver; 
but  for  every  one  of  this  type  listener, 
there  are  one  hundred  of  the  her  type 
who  want  to  know  all  about  il  id  spend 
much  of  their  time  in  trying  to  I  a  thorn  the 
mysteries  of  the  art. 

The  more  study  one  gives  to  this  sub- 
ject, the  more  fascinating  it  becomes; 
how  sound  can  be  impressed  upon  the 
diaphragm  of  the  microphone,  changed 
into  electrical  energy  and  passed  through 
thousands  of  miles  of  space  to  be  trans- 
formed again  into  the  same  sounds  which 
were  produced  before  the  microphone. 
How  a  wire,  placed  high  in  the  air  and 
connected  through  the  receiving  set  to  the 
ground,  can  collect  enough  of  this  energy 
to  be  again  transformed  into  sound  with 
even  greater  volume  than  the  original 
sound  at  the  microphone,  is  one  of  the 
seeming  impossibilities  which  has  been 
achieved  by  the  science  of  radio.  To 
fully  understand  how  this  feat  is  per- 
formed, one  must  refer  back  to  one  of  the 
elementary  laws  of  electricity  which  states 
that  tiny  lines  of  magnetic  force  surround 
any  conductor  through  which  a  current 
of  electricity  is  flowing. 

Kinds  of  Conductors 

TT  matters  not  whether  this  conductor 
^  be  a  wire  with  current  flowing  through 
it,  or  an  insulating  medium,  such  as  air, 
which  has  been  broken  down  by  a  high 
electric  pressure  to  such  an  extent  that 
electric  current  is  forced  through  it. 
The  blaze  which  one  sees  between  the 
carbons  of  an  arch  lamp  is  a  flow  of 
electrical  energy  made  possible  by  so 
heating  the  air  between  the  carbons,  that 
it  becomes  a  conductor  instead  of  an 
insulator.       Here    we   also    find    lines   of 


The  Magazine  of  the  Hour 

C[  Fathoming  Radio's  Deepest  Mysteries 

The  Theory  of  Radio 

Transmission  and 

Reception 

By  FRANK  D.  PEARNE 


10 


AER. 


AL 


y 


HIGH  FREQUENCY  WAVE 
C 


ground    mow  diaphragm 

_  -  should  move  to 

—      produce:  sound 

Fig.  2. 


magnetic  force  surrounding  the  flame 
although  air  is  considered  to  be  an  in- 
sulator and  therefore  a  non-conductor 
of  electricity.  In  any  event,  when  elec- 
tricity moves,  whether  it  be  a  static  dis- 
charge or  current  produced  by  a  battery, 
dynamo  or  any  other  source,  these  mag- 
netic lines  of  force  will  be  present. 

According  to  theory,  these  lines  are 
whirlingaroundthe  current, thenumber  of 
them,  and  the  distance  which  they  reach 
from  the  center  of  the  charge,  depending 
upon  the  strength  of  the  current.  Be- 
cause they  surround  the  current,  they 
must  be  at  right  angles  to  the  direction 
in  which  the  current  is  flowing. 

For  example,  if  a  conductor  placed  in  a 
vertical  position  is  traversed  by  a  current 
of  electricity,  the  lines  of  force  will  emerge 
in  a  horizontal  plane.  If  another  con- 
ductor having  its  circuit  closed  is  placed 
near  enough  to  the  first  one,  so  that  it  will 
be  within  the  range  of  the  lines  of  force, 
then  at  the  time  the  lines  move  outward 
or  fall  back,  they  will  cut  through  this 
second  wire  and  produce  a  current  in  it. 
Such  an  action,  however,  only  takes  place 
while  the  lines  are  moving  in  or  out. 

Thus,  as  shown  in  Fig.  1,  if  the  key  is 
pressed,  the  circuit  is  closed  and  the 
lines  come  out  in  circles  until  they  reach 
their  maximum  position,  after  which  they 
cease  to  progress  outward.  If  the  key  is 
released,  they  fall  back  again  and  dis- 
appear. Thus  they  only  cut  through  the 
second  conductor  while  they  are  moving 
in  or  out,  and  the  meter  in  the  second 


conductor  will  only  show  a  deflection 
during  this  movement,  which  will  only 
occur  at  the  time  the  circuit  is  closed,  or 
broken  by  the  key.  The  current  'in  the 
second  wire  is  produced  by  INDUC- 
TION. If  this  second  circuit  was  not 
complete;  that  is,  the  electrical  path  was 
broken,  then  no  current  would  be  induced 
in  the  second  wire  because  it  would  not 
have  a  complete  path  over  which  it  could 
flow,  and  the  meter  would  show  no 
deflection. 

Producing  A.  C. 

WITH  the  circuit  closed,  however, 
when  the  lines  move  outward  they 
cut  through  the  second  conductor  in  one 
direction  and  when  they  fall  back,  they 
cut  through  it  in  the  opposite  direction. 
Thus  in  one  case  the  current  produced 
will  be  in  one  direction  and  with  the 
reverse  of  the  cutting  the  current  will  be 
in  the  opposite  direction,  so  that  by 
rapidly  closing  and  opening  the  key,  an 
alternating  current  will  be  produced  in 
the  second  conductor. 


DIAPHRAGM  DOES  NOT  MOVE 
UNDER  INFLUENCE  OF  RAPIDLY 
OSCILLATING     WAVE 


POSITION  OF  DIAPHRAGM 
UNDER  INFLUENCE  OF 
RECTIFIED    WAVE 


FIG.  3 


So  much  for  the  elementary  lesson  in 
electricity.  Let  us  leave  this  for  a  time 
and  see  how  this  principle  is  used  in  the 
transmission  of  energy  from  the  broad- 
casting station  to  the  receiving  set.  In 
the  transmitter,  large  vacum  tubes  are 
used  for  setting  up  a  stream  of  oscilla- 
tions. An  extremely  high  pressure  is 
applied  to  the  plates  of  these  tubes  and 
the  grid  and  plate  circuits  are  so  ar- 
ranged that  one  re-acts  upon  the  other 
in  such  a  manner  that  when  this  high 
pressure  is  applied  to  the  transmitting 
aerial,  it  consists  essentially  of  an  altern- 
ating current  of  high  pressure  which 
alternates  from  several  hundred  thou- 
sand to  a  million  or  more  timesin  a  second. 
Where  such  high  frequencies  (number  o/ 


20 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


SHOWING    HOW   THE    TINY    MAGNETIC  LINES    OF 
FORCE  ARE   CARRIED     THROUGH     THE  ETHER    BY 
THE    CARRIER       WAVE     ,  AND     CUT     THROUGH  THE 
VERTICAL     PART    OF   THE    AERIAL     ON    THE 
RECEIVING     SET 

FIG.   5 


LONG  AERIAL 


HATER       ANALOGY      OF   AERIAL      CAPACITY 

Fl&.    6 


alternations  per  second)  are  used,  the 
term  "alternating"  is  usually  called 
"oscillating."  This  rapid  changing  of  the 
pressure  between  the  transmitting  aerial 
and  the  earth,  sets  up  a  series  of  strains 
upon  the  ether,  resulting  in  an  electro- 
static wave  being  set  free  from  the  aerial. 

Such  a  wave  is  shown  at  "A"  in  Figure 
4.  The  zero  line  passing  through  the 
center  of  the  wave  represents  time  and 
also  the  zero  point  from  which  the  wave 
rises  and  falls  at  each  time  it  changes 
direction.  This  is  really  what  is  known  as 
the  static  component  of  the  wave  and 
the  AMPLITUDE  of  the  wave  is  the 
highest  point  which  it  reaches  on  either 
side  of  this  zero  line. 

Now  this  static  component  is  really  a 
series  of  electrical  vibrations  which  will 
travel  freely  for  great  distances  through 
the  ether,  and  by  referring  back  to  the 
elementary  lesson,  we  must  assume  that 
each  line  of  this  wave  is  surrounded  with 
magnetic  lines  of  force,  as  shown  in 
Figure  S.  Those  lines  which  represent 
one  half  of  a  wave  are  surrounded  by 
lines  which  are  whirling  in  one  direction 
and  those  on  the  line  representing  the 
other  half  are  whirling  in  the  opposite 
direction.  So  by  means  of  this  static 
wave,  we  are  able  to  hurl  these  magnetic 


lines  through  the  ether  for  great  distances. 
By  again  referring  to  Figure  5,  it 
will  be  noted  that  the  greater  the  am- 
plitude of  the  wave,  the  more  of  these 
lines  of  force  will  be  carried,  and  the  more 
of  them  that  will  reach  the  receiving 
aerial.  The  greater  the  power  applied  to 
the  transmitting  aerial  the  greater  will 
be  the  amplitude  of  the  wave.  To  make 
matters  easier  to  understand,  let  us  con- 
sider that  the  greater  the  amplitude 
of  the  wave,  the  more  of  these  lines  of 
force  will  travel  with  it  and  consequently 
the  more  lines  will  reach  the  receiving 
aerial;  therefore,  in  explaining  the  theory, 
we  will  merely  refer  to  the  wave  in  its 
two  components;  the  static  and  the 
electro  magnetic.  Oscillating  at  such  high 
frequencies,  and  if  that  part  of  the  wave 
on  either  side  of  the  zero  line  could  be 
eliminated  and  only  that  on  the  other  side 
was  left,  the  time  between  the  peaks  of 
these  oscillations  would  be  so  small  that 
we  would  have  practically  a  direct  cur- 
rent which  might  be  indicated  by  a  line 
drawn  along  the  peaks  of  the  oscillations 
on  one  side  of  the  zero  line  at  "A"  Figure 
4,  and  eliminating  the  other  half  of  the 
wave  on  the  other  side. 

As  it  is,  however,  we  might  say  that 
we  have  two  sources  of  direct  current, 


one  above  the  zero  line  and  another  below 
it,  but  as  they  are  opposite  in  direction, 
the  direct  current  effect  is  zero,  because 
one  neutralizes  the  other.  This  is  exactly 
the  effect  we  would  get  if  we  connected  a 
pair  of  phones  between  the  receiving 
aerial  and  ground  as  shown  at  "A," 
Figure  2.  The  oscillations  would  be  far 
too  rapid  to  ever  move  a  heavy  phone 
diaphragm  and  if  they  did  move  it,  the 
frequency  would  be  entirely  too  high  to 
be  heard  by  the  human  ear. 

It  should  be  mentioned  here  that  the 
current  produced  in  the  aerial  of  the  re- 
ceiving set  is  induced  in  it  by  the  lines  of 
force  carried  by  the  static  component  of 
the  wave  being  made  to  cut  through  it, 
and  naturally  the  characteristics  of  such 
a  current  will  be  the  same  as  that  which 
produced  the  wave;  that  is,  it  will  be  an 
oscillating  current  of  the  same  frequency. 
Referring  to  Figure  2,  ("A")  shows  the 
phone  connected  in  the  aerial  circuit  with 
no  result.  "B"  shows  the  rapidly  oscillat- 
ing wave,  changing  too  fast  for  the  dia- 
phragm to  follow  it.  "C"  shows  the 
construction  of  the  phones  with  the 
diaphragm  stationary  and  "D"  shows 
how  the  diaphragm  should  move  to 
produce  a  sound  which  would  be  audible 
to  the  human  ear.  (Turn  to  page  59) 


RADIO  FREQUENCY     CARRIER     WAVE      PROPAGATED       THROUGH    ETHER      BY    BROADCASTING    STATIONS 


SAME      WAVE     AFTER       BEING-     MODULATED     BY       VOICE     IMPRESSED       UPON   THE  MICROPHONE    DIAPHRAGM 


SAME    MODULATED        WAVE         AFTER      PASSING     THROUGH      THE      DETECTOR      SET 

FIG.    4 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


21 


It  Now  is  But  a 
Matter  of  Time 
Before  the  Latest 
in  Receivers — the 
^Radio  Vision 
Outfit,  Will  Be 
in  Every  Home 


C.  Francis  Jenkins  and  the  prismatic  ring  of  lens  or  disk 
whereby  motion  pictures  were  sent  and  received  by  radio. 


"Television 
A  Fact  at 
Last,' Says 
Jenkins 

By  S.  R.  WINTERS 


This  photo   shows    Mr.  Jenkins   and   the   motion   picture   projecting 

machine  carrying  a  scene  of  a  Dutch  windmill,  the  first  movie  object 

sent  and  received  by  radio. 


THE  picture  flashed  on  the  screen 
in  a  motion  picture  theater  is  taken 
off  and  put  back  on  16  times  a 
second,  with  the  human  eye  unable  to 
detect  the  rapid  intermittent  changes. 
Similarly,  by  means  of  a  revolutionary  in- 
vention of  C.  Francis  Jenkins  of  Wash- 
ington, D.  C,  motion  pictures  may  now 
come  into  your  home  by  the  medium  of 
radio  waves,  the  picture  being  completed 
with  the  unbelievable  swiftness  of  one- 
sixteenth  of  a  second. 

The  first  official  demonstration  was 
given  by  the  Jenkins  Laboratories  on 
June  13  when  the  scenes  of  a  dancing 
girl  were  transmitted  to  the  homes  of 
Hon.  Herbert  Hoover,  Secretary  of 
Commerce,  and  Colonel  Paul  Hender- 
son,      Second       Assistant       Postmaster 


General,  respectively.  The  machines  for 
receiving  these  moving  objects,  including 
views  on  a  standard  motion-picture  film 
as  well  as  the  movements  of  a  dancer, 
included  a  small  mahogany  cabinet,  the 
lid  of  which  contains  a  miniature  screen. 
Besides  this  there  are  a  small  electric 
motor  for  revolving  a  combination  of 
lens  disk  and  prismatic  rings,  and  a  tiny 
lamp,  which  flickers  one-half  million 
times  a  second. 

Radio  and  Sound  United 

THIS  radio-movie  set,  of  course,  in- 
cludes a  radio  receiving  outfit,  to- 
gether with  a  loud  speaker.  That  is  to 
say,  radio  sound  and  radio  vision  have 
been  joined  together,  thus  giving  reality 
to  the  term  "radio  vision"  or  "television." 


For  instance,  if  a  broadcasting  station  is 
transmitting  "movies"  taken  from  a 
theatre  motion-picture  screen,  in  the 
event  that  you  are  equipped  with  a 
Jenkins  radio-movie  set,  in  order  to  re- 
ceive these  pictures  the  lid  of  the  mahog- 
any cabinet  is  raised.  The  lid  of  this 
small  cabinet  or  box  contains  a  white 
screen  upon  which  the  motion  picture 
appears  as  soon  as  a  switch  is  pressed, 
which  puts  the  instrument  into  opera- 
tion. The  closing  of  this  switch  not  only 
places  the  radio  receiving  set  in  service 
but  it  starts  the  electric  motor  which 
drives  the  picture-receiving  apparatus. 

The  mechanism  for  sending  motion 
pictures  by  radio  is  not  quite  so  simple 
as  the  radio- mo  vie  receiving  station. 
First,  there  is  the  conventional  motion- 


22 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


picture  projector,  which  may  be  found 
in  thousands  of  "movie"  theaters.  Then 
there  is  a  prismatic  ring,  which  rotates 
in  front  of  a  lens,  the  purpose  of  this  unit 
being  to  draw  the  lines  which  make  up  a 
picture.  Of  course,  a  picture  is  nothing 
more  than  lights  and  shadows.  In  line 
with  this  disk  lens  are  two  prismatic 
rings — a  new  shape  in  optical  glass — 
which  in  revolving  changes  the  angle  of 
the  prism.  This  action  distributes  the 
lights  and  shadows  that  make  up  a  picture 
in  successive  adjacent  parallel  lines 
until  the  whole  picture  surface  is  covered. 
The  process  of  sending  a  motion  picture, 
however,  requires  the  infinitesimal  time 
of  only  one-sixteenth  of  a  second. 

Obviously,  motion  pictures  as  such  are 
not  hurled  through  space.  The  lights 
and  shadows  constituting  a  picture  are 
first  converted  into  an  electrical  value  or 
current.  This  seemingly  remarkable 
transformation  is  accomplished  by  a  so- 
called  light-sensitive  cell,  which  consists 
of  a  substance  (in  this  instance 
potassium),  that  actually  changes  the 
motion  picture  into  an  electric  current. 
As  such  it  is  impressed  on  a  radio-carrier 
wave,  which  is  picked  up  by  the  distant 
radio-motion-picture  receiving  outfit. 
Then,  of  course,  this  electrical  value  has 
to  be  again  converted  into  a  picture 
value.  This  is  done  by  mechanism  simi- 
lar to  that  at  the  transmitting  station; 
namely,  prismatic  glass  rings,  an  electric 
motor,  and  a  tiny  light,  which  is  ex- 
tinguished and  lighted  one-half  million 
times  a  second. 


'  I  ''HE  whole  picture  surface  is  covered 
-*-  in  one-sixteenth  of  a  second;  there- 
fore, the  persistence  of  vision  of  the 
human  eye  is  sufficient  to  obtain  a  picture 
from  the  white  screen  on  the  lid  of  the 
cabinet  of  the  receiving  outfit.  This 
obviates  the  necessity  of  using  a  photo- 
graphic plate. 

"When  the  machine  is  speeded  up," 
explains  Mr.  Jenkins,  "until  the  suc- 
cession of  lines  recurs  with  a  frequency 
which  deceives  the  eye  into  the  belief 
that  it  sees  all  these  lines  all  the  time, 
then  a  picture  suddenly  flashes  on  the 
white  screen  in  all  the  glory  of  its 
pantomime  mystery. 

"When  to  this  audible  radio,"  con- 
tinues Mr.  Jenkins  with  picturesque 
descriptive  terms,  "we  add  visible  radio, 
we  may  both  hear  and  see  great  events; 
inaugural  ceremonies;  a  football,  polo, 
or  baseball  game;  a  regatta,  mardi 
gras,  flower  festival,  or  baby  parade; 
and  an  entire  opera  in  both  action  and 
music. 

"Educationally,  the  extension  worker 
in  our  great  universities  may  then  illus- 
trate his  lecture,  for  the  distant  student 
can  see  as  well  as  hear  him  by  radio. 

"To  get  pictures  by  radio,  a  sensitive 
cell  converts  light  into  electrical  current, 
and  at  radio  distances  changes  these 
currents  back  into  light  values,  and  one 
may  see  the  distant  scene;  for  light  is  the 
thing  of  which  pictures  are  made,  as 
music  is  made  of  sound. 

"The  attainment  of  'television'  or  radio 
vision,   as  it   is  now  coming  more  com- 


monly to  be  called,  requires  that  the 
sending  shall  be  from  a  flat  plane,  and 
reception  on  a  flat  plane,  and  a  modula- 
tion which  will  give  not  only  the  high 
lights  and  shadows  but  the  half-tones  as 
well. 

What  the  Future  Holds 

'  I  ^HESE  flat  planes  may,  of  course,  be 
-*-  the  focal  planes  of  the  lenses  employed 
at  the  receiving  station,  and  from  the 
focal  depth  of  the  lens  at  the  sending 
station  where  the  picture  may  perhaps 
be  taken  from  living  actors  or  from  an 
outdoor  scene. 

"At  the  receiving  station  the  flat  sur- 
face may  be  a  photographic  plate,  a  white 
wall,  or  a  miniature  of  the  usual  'silver 
sheet'  of  the  motion  picture  theater. 

"When  the  'teloramaphone'  (name 
given  radio  vision  mechanism)  is  made 
generally  available,  then  pictures  at  the 
fireside  sent  from  the  distant  world 
points  will  be  the  daily  instructional 
class;  and  the  evening's  entertainment; 
and  equally  the  long  day  of  the  sick  and 
'shut-ins'  will  be  more  endurable;  and 
life  in  the  far  places  less  lonely,  for  the 
flight  of  radio  is  not  hindered  by  rain  or 
storm,  or  snow  blockades." 

Mr.  Jenkins,  whose  ingenuity  is  re- 
sponsible for  this  almost  incredible  scien- 
tific achievement,  about  thirty-five  years 
ago  invented  the  motion-picture  project- 
ing machines  that  are  now  used  in 
theaters  all  over  the  world.  For  this 
lasting  contribution,  he  was  awarded  a 
gold  medal  by  the  Franklin  Institute. 


The  elaborate  transmitting  apparatus  necessary  to  send  movies  over  the  radio  waves  is  shown  above.      It  is  a  scene  from  Mr.  Jenkins' 
laboratory,  which  has  been  the  home  of  these  remarkable  developments  during  the  past  year. 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour  23 


Unique  Map  Shows  How  Far  Radio 
Waves      ^^^^^^^      Travel 


SCALE,  MILES 


APPLIES ONLYTO DISTANCES  FROM 
SCHENECTADY.O?  BETWEEN  POINTS 
OH  UNE  THROUGH  SCHENECTADY. 


©  GENERAL  UECTBIC  COMPANY 


IF  YOU  have  ever  tried  to  figure  the 
distance  between  any  point  in  North 
America  and  a  city  in  Asia  or  South 
Africa,  making  due  allowance  for  the 
curvature  of  the  earth,  you  will  appre- 
ciate this  distorted  map  which  was  drawn 
for  the  convenience  of  radio  engineers  of 
the  General  Electric  Company  in  inter- 
preting transmission  tests 

It  is  known  as  an  "equidistant  zenithal 
projection,"  which  means  that  you  don't 
have  to  resort  to  spherical  trigonometry 
or  a  slide  rule  to  get  either  direction  or 
distance  between  two  points  on  the  face 
of  the  earth,  one  point  of  which  is  the 
center  of  the  map. 

This  map  is  drawn  with  Schenectady  as 
a  center  and  all  measurements,  to  be 
accurate,  must  be  from  or  to  Schenectady. 
An  entirely  different  distortion  would  be 
produced  if  the  map  were  drawn  with 
London   or  Melbourne  as  a  center. 


By  W.  T.  MEENAM 


The  projection  has  three  main  uses. 
First,  it  gives  the  straight  line  distance 
between  Schenectady  and  any  other 
point  on  the  earth's  surface.  This  is 
obtained  by  measuring  the  distance  from 
Schenectady  to  the  point  in  question  and 
converting  this  measurement  in  inches 
into  miles  by  means  of  the  scale  at  the 
bottom  of  the  map. 

The  map  is  valuable,  in  the  second 
place,  as  it  shows  the  nature  of  the  inter- 
vening territory  between  Schenectady 
and  any  other  point.  This  is  highly 
important  for  the  radio  engineer,  for, 
as  is  well  known,  the  distance  over  which 
radio  signals  can  be  transmitted  depends, 
among  other  things,  on  the  nature  of 
intervening    territory;    that    is,    whether 


it  is  land  or  water.  Distance  transmis- 
sion over  territory  three-fourths  of  which 
is  water  and  one-fourth  land  is  not  so 
difficult  as  transmission  over  the  same 
distance  three-fourths  land  and  one- 
fourth  water. 

In  the  third  place,  the  map  gives  the 
exact  bearing  or  direction  from  Schenec- 
tady to  any  other  point  on  the  earth's 
surface.  This  bearing  is  obtained  by 
extending  a  straight  line  through  Sche- 
nectady and  the  point  in  question  to  the 
scale  on  the  periphery  of  the  map  which 
reads  directly  in  degrees.  It  would  not 
be  supposed,  for  example,  that  radio 
signals  from  Schenectady  would  travel 
within  a  few  degrees  of  the  north  pole 
to  reach   Manila. 

The  average  person  would  not  expect 
a  radio  wave,  traveling  in  a  straight  line 
and  the  shortest  distance  to  Calcutta,  to 
take  a  north-easterlv  route. 


24 


RADIO  AGE  for  September,  1925 


What  the  Broadcasters  are  Doing 


Long-Range  Daylight 
Radio  Succeeds 


First  Results  of  MacMillan  s  Ex- 
peditions to  the  Arctic  Really 
Prove  Value  of  New  Theory;  Voice 
Reception  Also  Tried  by  Amateurs 


John  L.  Reinartz,  operator  of  the  MacMUlan  Arctic  Expe- 
ditions on  board  the  schooner  "Bowdoin,"  sitting  at  his 
short  wave  transmitter  which  is  now  cruising  the  polar  re- 
gions. It  is  from  this  cabin  that  the  radio  fans  of  the  world 
are  receiving  messages  from  the  greatest  of  all  Arctic  explor- 
ation parlies. 


REPORTS  received  daily  from  the 
MacMillan  Arctic  Expedition  by 
amateurs  at  various  points 
throughout  the  country  reveal  the  fact 
that  daylight  reception  at  long  range  has 
been   proven  an  outstanding  success. 

The  Reinartz  short  wave  circuit 
marked  a  new  era  in  radio  engineering 
success  and  opens  the  way  to  enter 
the  icebound  Arctic  Circle  with  greater 
safety  during  their  long  daytime  of  six 
months. 

Long  wave  apparatus  is  also  being 
carried  by  the  MacMillan  Expedition 
and  has  thus  far  produced  satisfactory 
communication  during  darkness  or  night 
hours,  but  during  the 
daytime  only  short  range 
communication  could  be 
established. 

U.  J.  Herrmann  re- 
ports that  the  S.  S. 
Peary  received  "voice" 
from  amateurs  located 
in  the  States  of  Alabama 
and  Florida.  Amateurs 
who  constructed  short 
wave  receiving  sets  and 
transmitters  from  the 
diagrams  of  this  low 
wave  circuit  report  pick- 
ing up  messages  at  var- 
ious intervals  from  the 
Peary  and  the  Bowdoin 
signed  by  MacMillan. 

By  the  first  of  August 
the  Expedition  was  to 
reach  and  establish  its 
principal  base  at  Etah, 
Greenland.  Further  ex- 
perimental work  on  both 
apparatus  in  communi- 
cation with  the  United 
States  will  reveal  a  closer 


checkup  on  what  may  be  termed  con- 
sistent communication,  which  will  then 
afford  engineers  a  more  comprehensive 
series  of  tests  upon  which  to  base  their 
final  conclusions.  This  will  be  followed 
by  further  tests  on  the  part  of  the  flyers 
who  will  leave  the  advance  base  and  ex- 
plore the  Unknown  area  which  is  expect- 
ed to  develop  the  discovery  of  a  new  con- 
tinent. 

The  Navy  -  MacMillan  -  Zenith 
Radio  Controversy 

TV /TUCH  publicity  has  been  given  to  the 
-!■»-*■   recent  Navy- MacMillan  Zenith  con- 


Commanders  MacMillan  (right)  and  McDonald  (left)  hold  their  last  conference 
at  Sydney,  N.  S.,  on  board  the  S.  S.  Peary,  prior  to  their  long  trek  into  the 
Arctic.  McDonald,  in  command  of  the  Peary,  will  follow  a  course  best  suited 
to  her  size  and  construction,  while  MacMillan  will  direct  the  course  of  the 
schooner  Bowdoin  likewise.  The  two  ships  will  separate  until  they  reach  their 
main  base  at  Etah,  Greenland. 


troversy  concerning  the  MacMillan  Arctic 
Expedition  sailing  from  Boston  and 
Wiscasset  without  the  Navy  Department 
radio  apparatus  being  carried  and  which, 
it  has  been  said,  was  contrary -to  Sec- 
retary of  the  Navy  Wilbur's  instruction. 
H.  H.  Roemer,  associated  with  Com- 
mander McDonald's  company  of  Chicago, 
gives   out   the   following  statement: 

"The  entire  controversy,  if  it  may  be 
termed  as  such,  grew  out  of  a  misunder- 
standing during  a  time  when  confusion 
prevailed  at  both  Boston  and  Wiscasset 
when  the  S.  S.  Peary  and  schooner  Bow- 
doin sailed  for  the  Arctic. 

"It  was  understood  by  Commanders 
MacMillan  and  McDon- 
ald that  the  Navy  ap- 
paratus formerly  used  on 
board  the  U.  S.  N.  S. 
S.  Florida  was  to  be  car- 
ried by  the  Expedition 
as  an  additional  meas- 
ure of  safety  to  the  men 
— but,  it  was  also  un- 
derstood that  the  Rein- 
artz 'short  wave  trans- 
mitting and  receiving 
apparatus  was  also  to 
be  included. 

"The  high  power  low 
frequency  apparatus 
operating  on  425  meters 
will  function  in  daylight 
between  the  exploring 
parties  when  not  far 
apart.  But,  on  the  other 
hand,  the  short  wave  ap- 
paratus, already  a  proven 
success  in  long  range 
daytime  reception,  will 
carry  farther  and  it  is 
( Turn  to  page  62) 


RADIO  AGE  for  September,  1925 


What  the  Broadcasters  are  Doing  25 


Presenting  Radio  s  Most 
Original  Program! 


Jimmie  Wilson's  famous  KFRU  Catfish  String  Band  presents  a  program 
every  Tuesday  evening  by  remote  control  from  the  banks  of  the  old  Pole 
Cat  Creek  about  four  miles  from  the  station,  and  if  you  listen  in  on  this 
program,  you  will  hear  the  most  unique  and  original  presentation  possible. 
For  instance,  you  will  hear  the  big  bull  frogs,  the  little  frogs,  tree  owls, 
crickets,  whip-poor-wills,  hear  the  coffee  boiling,  hear  the  fish  frying, 
and  all  of  the  different  sounds  natural  to  a  real  Summer-time  fishing  trip. 
Different,  eh? 


26  RADIO  AGE  for  September,  1925 


What  the  Broadcasters  are  Doing 


An  INSPIRATIONAL  Studio 

By  GALE  HENRY 


*^^=l    I 


At  the  right  is  an 
artist's  conception 
of  the  beautiful  ar- 
rangement of  Zen- 
ith's new  WJAZ 
studio  in  the  Straus 
Building,   Chicago 


Environment  and  Atmosphere  Are  Embodied  in 
Elaborate  New  Studio  Just  Opened  by  Station 
WJAZ  in  Chicago;  Impressive  Scenic  Effects  Used 


THE  above  picture  illustrates  one 
section  of  the  new  Zenith  Broad- 
casting Station,  WJAZ,  located  on 
the  twenty-third  floor  in  the  tower  of 
the  new  Straus  Building,  Chicago,  111. 
"Better  broadcasting  begins  with 
better  studios  and  that  means  environ- 
ment and  atmosphere" — said  E.  F. 
McDonald,  President  of  the  National 
Association  of  Broadcasters — "and  we 
propose  to  prove  the  point." 

Thus  far  quality  reception  has  been 
considered  purely  a  matter  of  acoustics, 
and  with  no  thought  of  the  more  import- 
ant question  of  environment  essential  to 
the  artists'  inspiration  and  atmosphere  to 
excite   quality  rendition. 

WJAZ  abandoned  completely  the 
standard  heavy  dull  drapes  prevalent  in 
almost  all  studios  and  through  the 
country's  highest  rated  acoustic  and 
electrical  authorities,  have  overcome  all 
obstacles  of  echo  and  sound  rebound 
without  the  use  of  the  drapes  and  accom- 
plished the  one  remaining  necessity — 
local  color  and  atmosphere. 

Before  entering  the  studio  one  comes 
into  a  reception  room  of  unusually  large 
dimensions — set  with  costly  tapestries 
and  carpetings  and  set  in  period  furni- 
ture.    To  the  right  is  an  artistic  archway 


within  which  a  massive  art  metal  gate 
fills  in  the  enclosure.  Flanked  on  either 
side  by  smaller  archways  are  wrought 
iron  gratings,  beneath  which  artistically 
built-in  benches  are  positioned,  this  room 
being  given  over  exclusively  as  a  lounge 
for  visitors  and  artists. 

Passing  through  a  great  archway  and 
into  the  studio  proper,  one  first  comes 
upon  a  great  wide  veranda — giving  the 
impression  of  having  left  the  drawing 
room  of  a  chateau  and  out  into  the 
garden. 

Here  the  visitors  are  seated  in  exquisite 
lawn  furniture  and  apart  from  the  artists 
in  the  garden  beyond.  The  studio 
proper  is,  in  a  sense,  a  garden  surrounded 
by  a  massive  wall  with  grilled  openings 
and  great  gateways  overlooking  a  vast 
area  of  country  beyond,  accomplished  by 
certain    scenic    effects. 

In  the  center  stands  a  massive  art 
fountain  of  stone  which  adds  a  touch  of 
realism  with  its  tiny  spray  of  water 
noiselessly  sparkling  and  enlivening  the 
Japanese  goldfish  within  its  spacious 
reservoir. 

The  ancient  tiled  flooring  is  here  and 
there  offset'  by  an  occasional  stone  seat 
or  other  appropriate  settings,  all  of  which 
lends  a  touch  of  ancient  days  and  a  silent 


effect  that  plays  upon  the  emotions. 
WJAZ,  however,  has  not  left  any 
details  to  the  artists'  imagination. 
Elaborate  electrical  apparatus  ingenious- 
ly concealed  throughout  the  entire 
setting  of  both  the  garden  and  the  veran- 
da is  operated  by  the  property  man  in 
charge  of  lighting  from  his  station,  which 
is  also  hidden  from  view,  but  from  which 
he  can  see  the  entire  performance. 
Automatically  controlled  lighting  appara- 
tus is  positioned  scientifically  to  produce 
certain  perfect  effects — the  operator 
follows  the  theme  of  the  selection  being 
broadcast,  and  with  flood  lights,  fadeins 
and  fadeouts,  he  produces  the  effect  of 
sunrise,  sunset  and  moonlight  as  in  day 
and  night — and  likewise  the  calms  and 
storms — all  with  such  faithful  effect  and 
reality  as  start  the  emotions  and  inspires 
the  artist's  greatest  effort. 

One  can  readily  picture  the  effect  upon 
the  artist  as  he  feels  the  richness  of  such 
environment  and  is  carried  along  with 
the  theme  of  his  role  by  the  effect  of  such 
surroundings  and  lighting  which  so  faith- 
fully follow  his  emotions,  while  he  also 
feels  the  intimate  closeness  of  an  audience 
actually  sitting  before  him,  midst  all  the 
richness  of  an  ancient  veranda  and 
garden. 


RADIO  AGE  for  September,  1925 


What  the  Broadcasters  are  Doing  27 


How  Radio 

is  Breaking 

Down  Rural 

Isolation 


By  A.  C.  E. 
SCHONEMANN 


RADIO  is  bringing 
about  a  social  rev- 
-  olution  in  the  Unit- 
ed States,  and  there  is  no 
place  where  this  is  more 
apparent  than  on  the  farm. 
The  farmer's  life  has  been 
brightened,  his  interest  has 
been  increased  and  every 
member  of  the  family  circle 
has  been  enriched  as  a 
result  of  radio. 

Of  the  half  million  or 
more  radio  sets  being  used 
on  the  farm  today,  most  of 
them  are  home  made. 
Some  are  crystal  sets,  and 
while  there  are  a  few  with 
more  than  three  tubes,  the  majority  possess 
between  one  and  three  stages  of  ampli- 
fication. 

The  interest  in  radio  on  the  part  of 
the  farmer  has  been  brought  about  largely 
through  his  own  efforts.  He  has  found 
in  it  a  long  sought  opportunity  to  cancel 
the  isolation  that  surrounds  rural  life. 
In  radio  he  has  an  ally  because  through 
it  the  family  relationship  becomes  greater, 
and  consequently  there  is  a  common 
interest  in  the  evening  program,  as  it 
comes  after  the  supper  hour  out  of  the 
night,  via  the  loud  speaker. 

Regardless  of  the  likes  and  dislikes  on 
the  part  of  the  rural  household,  there  is 
an  appeal  back  of  radio  programs  that 
extends  from  one  end  of  the  family  to 
the  other,  and  as  a  result  radio  has  be- 
come firmly  intrenched  in  the  affections 
of  young  and  old  on  the  farm.  Every- 
one, with  all  the  diversity  that  taste 
can  offer,  has  some  feature  that  carries 
an  appeal,  and  it  is  variety  coupled  with 
the  personality  back  of  the  human  voice, 
that  has  made  radio  something  more  than 
a  passing  attraction  to  the  farmer.  To 
him  it  is  an  hour  of  relaxation  when  the 
sweet  amenities  of  the  family  are  inter- 
mingled with  the  delightful  and  pleasing 
entertainment  that  radio  provides. 

How  the  College  Helps 

TOWA  State  College,  which  is  located 
•*-  in  the  heart  of  the  corn  belt  near 
Ames,  la.,  has  been  a  sort  of  evangel  in 
carrying  to  the  farmers  of  the  Mississippi 
Valley  a  sense  of  appreciation  of  radio. 
Before  the  war  weather  reports  were 
broadcast  from  the  college  and  during 
the  last  few  years  the  scope  of  its  work 


The  insert  at  left  shows  Prof.  D.  C.  Faber,  director  of  the  engineering 

extension    department  at  Ames  (la.)  College.      He  has  charge  of  the 

short  courses    in  radio  at  the  college,   which  maintains  Station  WOI . 

The  neat  room  in  the  picture  above  is  the  operating  room  at  WOI . 


as  applied  to  broad- 
casting has  increased 
until  today  Iowa  State 
College  operates  Station 
WOI,  which  is  a  farmers'  station,  not 
only  in  name  but  in  fact. 

WOI  is  maintained  for  the  farmer  by 
men  who  have  had  practical  farm  exper- 
ience. Further  proof  of  the  farmers' 
hold  on  WOI  is  that  it  functions  daily 
"out  where  the  tall  corn  grows"  in  central 
Iowa.  Here  farming  and  the  kindred 
subjects  that  make  for  its  success  are 
taught  and  exemplified  on  a  scientific 
basis. 

The  Iowa  State  College  not  only  broad- 
casts for  the  benefit  of  the  farmer,  but 
it  sponsors  yearly  a  short  course  for 
Iowa  radio  amateurs.  Further,  it  has 
provided  a  course  in  radio  construction 
which  has  enabled  the  farmer  and  espe- 
cially the  boys  and  girls  on  the  farm  to 
build  their  own  sets. 

The  studio  of  WOI  is  tucked  away  on  the 
third  floor  in  a  brick  building  adjacent 
to  Engineering  Hall. 

As  is  true  of  most  studios,  simplicity 
prevails  at  WOI.  Heavy,  gray  draperies 
hang  from  the  walls;  there  is  a  piano, 
several  pieces  of  furniture,  two  micro- 
phones, a  reception  room  and  apartment 
which  contains  the  electrical  equipment 
of  the  station. 

There  are  no  great  steel  towers  carry- 
ing the  aerials  of  WOI,  which  has  a 
wave  length  of  270  meters  and  power  of 
500  watts.  The  electrical  engineering 
department  of  the  college,  whose  mem- 
bers designed,  built  and  now  operate 
the  station,  have  utilized  a  gigantic 
water  tank  which  is  located  opposite  the 
engineering  building  and  a  massive 
smoke  stack  situated  150  yards  or  more 
south,  as  towers  for  the  aerials  which 
carry  the  lead-in  wires  to  the  studio. 


'  I  ''HE  programs  of  Station  WOI  are 
-*-  prepared  by  a  committee  drawn  from 
the  faculty  of  Iowa  State  College,  and 
since  the  opening  of  the  station  in  May, 
1922,  schedules  have  been  planned  and 
carried  out  with  but  one  thought  in 
mind — the  farmer.  His  problems  and 
his  needs  have  been  given  first  considera- 
tion, the  idea  of  the  program  committee 
being  to  make  WOI  an  indispensable 
factor  to  the  farmer  in  his  work. 

That  WOI  has  carried  the  gospel  of 
good  farming  via  the  ether  to  the  farmer 
is  evident  from  the  thousands  of  letters 
that  are  received  weekly  from  every 
section  of  the  United  States.  While 
the  greatest  range  of  WOI  has  been 
3,100  miles,  and  its  programs  have  been 
picked  up  in  Alaska,  Samoa,  Porto 
Rico  and  New  Brunswick,  the  real  inter- 
est in  Iowa's  100  per  cent  farm  station  is 
in  the  Mississippi  valley,  where  the 
various  market  reports  and  seasonal 
lectures  are  followed  closely  by  the 
farmer. 

The  week-day  schedule  of  WOI  in- 
cludes three  weather  reports  presented 
at  9:30  a.  m.,  12:30  p.  m.,  and  9:30  p.  m. 
Another  daily  feature  is  the  market 
reports,  including  grain  and  livestock; 
also  various  crop  bulletins  (state  and 
national)  together  with  lectures  which 
are  given  by  various  members  of  the 
faculty  at  Iowa  State  College. 

The  lectures  are  presented  in  a  series. 
They  are  educational  and  calculated  to 
appeal  to  the  farmer  who  operates  on  a 
large  scale,  as  well  as  the  man  who  main- 
tains a  garden  in  the  back  yard.  Twice 
each  week  there  are  programs  of  music, 
one  evening  being  devoted  to  the  works 
of  the  masters  and  the  other  is  given 
over  to  the  presentation  of  popular  music. 
Another  feature  sent  out  from  WOI 
(Turn  to  page  63) 


28 


RADIO  AGE  for  September,  1925 


What  the  Broadcasters  are  Doing 


Everyone  Tunes  in  California — Because 

Distance  by  Radio  Lends- \ 
Enchantment! 

By  DR.  FRANK  L.  POWER 


Sylvia  Breamer,  talented  film 
star,  who  has  been  charming 
the  fans  for  years,  has  been 
discovered  to  have  a  "silvery 
voice"  for  radio.  As  a  result 
she  is  in  demand  throughout 
California.  She  gives  pleas- 
ing,   interesting    talks. 


HOLLYWOOD  and  Los  Angeles 
continue  to  entertain  radio  fans 
all  over  the  country  with  breezy 
chats  from  prominent  film  people  and 
tuneful  melodies  from  stage  and  screen 
stars  who  are  fortunate  enough  to  have 
the  necessary  talent. 

Probably  .the    radio     programs    from 
Southern  Cal- 
ifornia are  no 
better   than 
those  in  other 
parts    of    the 
country,     but 
distance  al- 
ways   lends 
enchantment. 
Then,  too,  so 
many    radio 
ent  h  usiasts 
are     movie 
f ans ,     also, 
that    there   is 
an   added   in- 
centive    to 
listen  to  radio 
progra  ms 
from  the   Pa- 
cific   So  u t  h  - 
west. 
There's  talented  Sylvia  Breamer,  well 
known   film   star,   for   instance,   who   al- 
ways enchants  radioland  with  her  silvery 
voice  and  she  has  taken  part  repeatedly 
in    the    film    star    program    which     the 
Wampus,     official     movie     organization, 
presents  on  alternate  Wednesdays  from 
9  to  10,  Pacific  time,  at  KFI. 

Then,  again,  there's  Lucille,  who  made 
countless  friends  in  radioland  by  her 
singing,  and  hundreds  who  heard  her 
sing  have  been  to  see  her  dance.  When 
radio  is  developed  to  the  extent  where 
you  can  actually  see  the  performers,  then 
Lucille  will  receive  many  more  applause 
cards. 

Most  people  do  not  know  it,  but  Hazel 
Brewster,  famous  harp  soloist,  is  a  sister 
of  Victor  Schertzinger,  film  director  and 
composer  of  many  popular  song  hits,  the 
best  known  of  which  is  "Marchetta." 
Hazel  Schertzinger  Brewster  has  taken 
part  in  many  delightful  musical  hours 
from  KHJ  and  KFI. 

Stedman  Gives  Plays 

1X/T  ARSHALL  Stedman,  dramatic  read- 
-!»-*■  er,  has  appeared  at  all  of  the  radio 
stations  in  Southern  California  during 
the  last  three  years,  and  his  radio  plays 
have  won  for  him  hearty  applause  cards 
from  all  corners  of  the  globe. 

With  the  erection  of  KFWB,  owned 
by  Warner  Brothers  motion  picture 
studio,  the  raging  controversy  about 
radio  displacing  the  films  has  received  a 


sad  jolt.  There  can  be  little  doubt  at 
this  time  but  that  radio  will  supplement 
and  not  displace  the  films,  just  as  radio 
supplements  the  newspapers  but  does 
not  displace  them. 

Carey  Wilson  has  been  giving  a  series 
of  twelve  radio  talks  on  scenario  writing, 
and  he  has  this  to  say  of  the  situation: 
"Radio  does  not  endanger  motion  pic- 
tures any  more  than  the  present  ten- 
dency toward  short  and  skimpy  skirts 
endangers  the  cloak  and  suit  industry." 
Wilson,  now  scenario  editor  for  the  huge 
combine  of  Metro-Goldwyn-Mayer,  has 
been  in  his  chosen  field  for  twelve  years. 
He  is  the  author  of  the  "Ben  Hur" 
scenario,  "He  Who  Gets  Slapped,"  and 
others,  and  speaks  with  considerable 
authority. 

Another  radio  enthusiast  in  the  ranks 
of  the  film  industry  is  Milton  Sills,  who 
never  misses  an  opportunity  to  give  a 
little  radio  chat.  When  he  was  elected 
King  of  the  Raisin  Festival  at  Fresno, 
he  accepted  via  radio,  as  did  Lew  Cody 
when  he  also  was  "King  for  a  day." 

Out  in  Hollywood,  both  KNX  and 
KFWB  are  essentially  film  fan  stations. 
In  Los  Angeles,  KFI  has  the  majority  of 
movie  celebrities  on  its  programs,  with 
KHJ  a  close  second. 

Bridging  the  Gulf 

NATURALLY,  the  broadcasters  of 
California  during  the  past  few 
months  have  been  wondering  with  what 
success  their  offerings  have  been  trans- 
mitted to  the  East.  Several  broadcast- 
ers have  become  discouraged  and  have 
claimed  it  was  well  nigh  impossible  to 
bridge  the  Rocky  Mountains  during  the 
time  when  Static  was  at  its  worst. 

So  the  surprise  was  most  welcome  when 
it  was  announced  that  several  California 
radio  stations  which  had  trouble  in  being 
heard  in  their  own  neighborhoods  were  be- 
ing received  during  the  warmth  of  July  with 
clear  loud 
speaker  vol- 
ume, as  far 
East  as  Chic- 
ago. 

That  is 
quite  an  ac- 
compli s  fa- 
me n  t  ,  al- 
though the 
type  of  circuit 
used  had  just 
as  much  to  do 
with  the  rec- 
ords reported 
as  did  the 
power  of 
the  transmit- 
ting    station. 


Out  on  the  West 
Coast  There's  No 
End  to  Supply 
of  Radio  Talent 


Marshall  Stedman,  dramatist, 
has  charge  of  radio  playlets 
which  he  produces  regularly 
from  most  of  the  Southern 
California  stations. 


Lucille,  from  the  Turkish  village  in  Los 
Angeles,  has  made  a  host  of  friends  through 
California  radio  stations.  Those  who 
liked  her  entrancing  voice  were  naturally 
agreeably  surprised  when  they  went  to 
the  "Village"  and  saw  her  in  real  life — 
all  "dressed  down"  'n  everything! 


The  announcement  that  California  was 
"coming  in"  with  loud  speaker  force  be- 
yound  the  Rockies  was  spread  all  over 
the  Coast,  and  as  a  result  the  old  inter- 
est in  broadcasting  is  being  revived.  It 
might  just  as  well  be  Winter-time,  judg- 
ing from  the  number  of  applicants  ap- 
pearing at  stations  daily. 

Recently  several  Eastern  broadcasters 
decided  to  entertain  the  feasibility  of 
broadcasting  criminal  and  civil  court 
trials  by  radio.  Such  a  storm  of  protest 
greeted  the  proposal  that  it  was  hushed 
down  before  a  plan  could  be  matera'ized. 

However,  when  it  was  learned  that 
"Mary  and  Doug"  of  movie  fame  were 
going  to  testify  in  a  kidnaping  trial 
in  Los  Angeles,  the  Coast  stations  were 
besieged  with  requests  to  put  their  testi- 
mony on  the  air.  The  same  requests 
were  sent  in  at  the  opening  of  several 
other  trials  in  California,  of  more  or  less 
importance. 

Which  all  goes  to  prove  that  distance 
does  lend  enchantment,  if  it's  by  radio, 
and  if  the  broadcaster  is  assured  he's 
bridging  the  great  open  ethereal  spaces. 


RADIO  AGE  for  August,  1925 


What  the  Broadcasters  are  Doing 


29 


Capturing  the  Artistic  Spirit  of  France 


"Get  away  from  me,  boys,  you  bother  me!" 
made  Clyde  Hager,  shown  above,  famous  at 
WQJ,  Chicago.  Now  he's  equally  famous 
as  director  and  eccentric  announcer  from 
WMBB  on  the  Trianon,  Chicago. 

WORLD'S  Most  Beautiful  Ball- 
room" (that's  saying  a  mouth- 
ful, isn't  it? — but  it's  true)  is 
the  meaning  of  WMBB,  the  radio  station 
on  the  Trianon  Ballroom,  Chicago,  with 
which  all  mid-west  radio  fans  have  be- 
come familiar. 

It's  the  home  of  Clyde  Hager,  the 
famous  street  fakir,  and  Dell  Lampe  and 
the  Trianon  Orchestra,  of  "Little  Orphan 
Annie,"  "Uncle  Tom's  Tunes,"  the 
"Bandelero,"  and  the  most  delightful 
entertainment  that  a  fan  has  ever  tuned 
his  dial  to. 

The  Trianon  ball- 
room, with  its  won- 
derful eliptical  dance 
floor,  and  magnifi- 
cent decoration  sand 
appointments,  is 
one  of  the  most 
famous  ballrooms  in 
the  world,  and  has 
made  Chicago's 
south  side  renowned. 
The  owner  is  An- 
drew Karzas,  and 
on  Cottage  Grove 
and  62nd  street, 
where  it  is  located, 
the  magnificent 
pleasure  palace  rep- 
resents a  dream 
come  true. 

Many  years  ago 
Andrew  Karzas 
came  from  Greece, 
with  a  great  deal 
of  money  to  make, 
and  very  little  in 
his  exotic  jeans. 
But  it  wasn't  long 
until  he  built  the 
first  theater  which 
healded  the  era  of 
the   gorgeous    mov- 


Fine 

Programs 

from  WMBB 

Carry  Hint  of 

Old-World 

Romance 

By 

MILTON 

LIEBERMAN 


ing  picture  homes.  It  was  the  Wood- 
lawn  Theatre,  and  made  of  much  more 
than  seats  and  a  screen.  It  was  built 
with  a  grandiloquence  of  architectural 
execution,  with  famous  paintings  on  the 
walls,  and  a  unique  lighting  system,  and 
frescoed   ceiling. 

His   Dreams   Visualized 

YA/TTH  prosperity  came  new  dreams, 
'  *  and  the  Trianon  followed,  designed 
after  the  style  of  the  famous  French 
Trianon,  the  pleasure  palace  of  Queen 
Marie  Antoinette,  built  by  Louis  XVI. 
It  cost  over  a  million  dollars  and  is  more 
magnificent  than  its  prototype  in  France. 
And  upon  this  palace  of  ballroom  gran- 
deur was  constructed  WMBB. 

J.  B.  Lampe,  director  of  the  Trianon 


The  Trianon  Ensemble  is  shown  above  in  a  jazzful  mood,  but  jazz  by  no  means  controls 

their  repertoire.      They  may  be  heard  nightly  in  varied  offerings  from  the  "World's  Most 

Beautiful  Boil-room"' 


Equally  adept  at  classical  or  popular  airs — 

is  Miss  Hazel  O'Neill,  the  lass  from  Erin 

who  enjoys  the  position  as  staff  soprano  for 

WMBB. 


Orchestra,  is  director  of  the  radio  station, 
and  Clyde  Hager  is  announcer.  Clyde 
Hager  was  taken  from  WQJ,  where  he 
entertained  with  Jerry  Sullivan.  His 
street  fakir  dialogue,  in  which  he  takes 
the  part  of  a  curb  vender,  selling  a  genu- 
ine rubber  garter,  and  continually  warn- 
ing the  crowd:  "Keep  away  from  me  boys, 
you  bothah  me!"  brought  him  great  fame 
at  WQJ  and  he  frequently  repeats  it  at 
WMBB,  to  the  delight  of  the  listeners. 
WMBB,  although  located  on  the  ball- 
room, broadcasting  some  of  the  finest 
jazz  music  which 
Dell  Lampe  and  the 
Trianon  orchestra 
can  give,  has  also 
become  famous  for 
its  classical  and 
semi-classical  music. 
The  classical  por- 
tion is  given  by 
Armin  F.  Hand  and 
the  W  o  o  d 1  a  w  n 
Theatre  concert  or- 
chestra  which 
broadcasts  by  spe- 
cial wire  from  the 
Woodlawn,  about 
three  blocks  away,  to 
WMBB.  The  Tria- 
non ensemble  also 
takes  part  in  the 
classical  programs. 
"Little  Orphan 
Annie"  has  become 
a  popular  feature. 
It  was  inspired  by 
Gray's  cartoon  in 
the  Chicago  Trib- 
une, which  tells  the 
story  of  the  little 
orphan  of  poetical 
fame,  who  "has 
come  to  our  house 
(Turn  to  page  62) 


30 


RADIO  AGE  for  September,  1925 


What  the  Broadcasters  are  Doing 


A  Girl  Reporter- Announcer  Speaks  Up: 

RADIO  IN  DAYS  OF  YORE 


EVERY  so  often 
somebody  feels 
it  his  bounden 
duty  to  come  forth 
and  announce  sagely 
that  radio  is  in  its  in- 
fancy. 

I  don't  know 
whether  people  say 
this  because  they've 
studied  the  matter 
and  have  really  esti- 
mated radio's  possi- 
bilities, or  whether 
they  say  it  simply  to 
have  something  with 
which  to  set  their 
tongues  in  motion. 

Anyway,  it  strikes 
me  that  the  phrase  is 
getting  a  bit  time- 
worn.  Radio  may  not 
have  reached  matur- 
ity as  yet  but  it  does 
seem  to  have  at  least 
got   out   of   rompers. 

It  has  been  almost 
four  years  since  I  was 
radio  editor,  program 
director,  studio  man- 
ager, chief  announcer 
and  general  rousta- 
bout for  the  first 
broadcast  station  in 
Memphis,  Tenn.  As 
I  compare  that  first 
station  with  the  ones 
that  are  now  in  use, 
it  seems  to  me  that 
there  is  nothing  that 
has  grown  faster  than 
radio  in  the  last  four 
years  unless  it  be  that 
Mr.  Jackie  Coogan. 

The  present-day  radio  stations  have  a 
staff  of  anywhere  from  10  to  35  indi- 
viduals. Our  staff  in  those  days  con- 
sisted of  two.  My  only  assistant  was  a 
young  chap  by  the  name  of  Percy  Root, 
who  took  care  of  the  mechanical  end  of 
the  station  at  night  and,  during  the  day, 
worked  at  something  else,  I  don't  remem- 
ber just  what. 

So  Little  To  Do! 

T^OR  myself,  I  worked  during  the  day 
-*-  as  reporter  on  the  newspaper  which 
sponsored  the  station.  In  addition  to 
my  general  assignments,  I  wrote  all  the 
material  for  the  radio  column,  engaged 
the  radio  artists  and  arranged  the  pro- 
grams. At  night  I  went  out  to  the  studio 
and  broadcast. 

I'm  not  trying  to  steal  anybody's 
thunder  by  boasting  about  how  much 
work  Percy  and  I  could  do.  I'm  merely 
pointing  out  that  radio  stations  have,  in 


Given   Wagner,  writer  of  this  article,  furnishes  the  above  picture  as  ample  proof 

that  she  was  "Everything  and  a  little  more"  in  the  early  (and  few)  days  of  WPO, 

Memphis,  Tenn.    When  she  wasn't  announcing  she  was  doing  1,001  other  things, 

a  few  of  which  are  explained  in  this  amusing  article. 


eminent   actor, 


BY  GWEN  WAGNER 

the  space  of  a  few  years,  grown  to  where 
they  require  a  staff  of  from  10  to  35 
people,  whereas  in  the  beginning  two 
could  handle  the  work  pretty  easily! 

These  present-day  studios  have  velvet 
hangings,  deep,  rich  rugs,  Baby  Grand 
pianos,  pipe  organs,  period  furniture  and 
a  general  air  of  elegance.  Our  station 
had  none  of  these  things.  It  was  located 
in  a  stock  room  of  the  wholesale  accessory 
house  which  provided  our  broadcasting 
set  in  return  for  publicity.  We  didn't 
have  any  rug  on  the  floor.  We  didn't 
have  any  velvet  hangings.  All  we  had 
was  a  counter  upon  which  our  broad- 
casting set  stood,  an  upright  piano,  a 
phonograph  and  a  big  horn.  It  was 
through  the  horn  that  we  broadcast. 
Sometimes  we  had  enough  chairs  to 
seat  all  the  people  who  were  kind  enough 
to  come  up  and  appear  on  our  programs, 
but  more  often  we  didn't. 


I  didn't  happen  to 
be  the  first  radio  edi- 
tor and  announcer 
in  Memphis.  A 
young  man  by  the 
name  of  Coyle  Shea, 
acknowledged  one  of 
the  shining  reportor- 
ial  lights  in  our  office, 
had  the  job  for  the 
first  four  weeks.  At 
the  end  of  that  time 
he  came  into  the  office 
and  announced  to  the 
publisher,  editors,  re- 
porters, copy  boys 
and  the  world  at  large 
that  he'd  be  blamed 
if  he  were  going  to 
chase  radio  talent  all 
day  and  then  run  out 
to  the  studio  at  night 
and  tell  bedtime  stor- 
ies to  the  kiddies. 

A  hasty  survey  of 
the  rest  of  the  staff 
was  taken.  Somebody 
had  to  be  gotten  in  a 
hurry  and  nobody 
wanted  the  job.  At 
last  the  eye  of  the 
managing  editor  fell 
upon  me.  I  was  the 
only  woman  on  the 
staff  and,  I  might  add, 
the  last  resort  in  this 
time  of  trouble. 

The  managing  edi- 
tor advised  me  to  take 
the  job.  He  pointed 
out  that  I  would  not 
only  meet  the  musical 
elite  of  the  city  but  that  I  also  would 
have  §10  added  to  my  weekly  salary. 

The  musical  elite  didn't  interest  me  but 
the  $10  did.  I  took  the  job  and  thus 
became  (as  I  was  later  exploited),  "the 
second  woman  announcer  in  the  United 
States  and  the  only  one  in  the  South." 
To  this  day  I  can't  figure  out  how  I 
ever  got  up  nerve  enough  to  stand  in 
front  of  that  gigantic  horn  for  the  first 
time  and  talk  to  what  I  fondly  believed 
were  millions  of  people.  Had  I  known 
then  what  I  did  later,  I  certainly  should 
not  have  been  so  perturbed.  Our  lis- 
teners could  not  have  numbered  more 
than  a  few  thousand.  The  ones  who  tried 
to  listen  in  on  us  and  failed  probably 
numbered  more. 

At  first  I  didn't  have  much  trouble 
getting  talent.  Folks  were  curious 
about  radio.  A  good  many  of  them  were 
anxious  to  try  it.  What  ruined  us, 
though,  was  that  the  voices  weren't 
received  as  they  were  sent  out.  In  some 
cases   I   was  glad  they  weren't.      I   can 


RADIO  AGE  for  September,  1925 


What  the  Broadcasters  Are  Doing    31 


remember  programs  when  I  all  but 
prayed  that  the  set  would  break 
down  and  I'd  have  to  call  off  the 
events.  In  those  days  we  didn't  have 
the  time,  much  less  the  nerve,  to  give 
trial  performances.  We  simply  had  to 
depend  upon  what  somebody  said  about 
Mrs.  So-and-So's  ability. 

Wotta  Life! 

THE  people  who  sang  for  us  got  it  into 
their  heads  that  if  the  horn  were 
tipped  a  certain  way  their  voices  would 
go  out  better.  Personally,  I  don't 
believe  that  anything  but  a  complete 
new  broadcasting  set  would  have  done 
any  good.  Nevertheless,  Percy  would 
tip  the  horn  this  way  and  that  and  the 
singers  wo\ild  teeter  back  and  forth  on 
their  heels  as  they  took  their  high  notes 
or  their  low  notes  and  it  was  pretty 
good  fun  to  watch  even  if  it  didn't  have 
any  effect  upon  the  way  the  voice  was 
going  out. 

"Good-evening!"  I  would  announce 
brightly,  "This  is  radio  station  WPO 
broadcasting  a  program,"  etc.,  etc. 

They  used  to  tell  me  that  the  "O" 
sounded  like  a  long  drawn-out  "ouw" 
coming  through  the  air;  something  the 
way  a  dog  howls  at  the  moon. 

If  any  present-day  radio  station  would 


Gwen's  manuscript  was  shown 
to  Fred  Hill,  who  has  charge  of  the 
technical  department  of  RADIO 
AGE,  to  see  if  he  could  better  the 
two-people  record  in  the  operation 
of  a  broadcasting  station. 

Fred  came  back  with  his  exper- 
ience in  the  early  days  as  the  owner 
of  station  WHAO,  at  Savannah, 
Ga.,  where  he  performed  the  follow- 
ing functions:  Owner,  engineer, 
announcer,  press  agent,  chauffeur, 
answerer    of    telephone,    recipient 

of   liq ■    and    conductor    of   the 

original"  night-hawk  session"  which 
went  on  the  air  from  WHAO  sev- 
eral months  before  Leo  Fitzpatrick 
came  on  with  WDAF. 


dare  broadcast  the  programs  that  we 
used  then,  it  would  be  run  off  the  air  in 
a  week.  I  do  not  mean  that  we  did  not 
have  any  good  talent.  We  did,  but,  as 
the  late  Bert  Williams  used  to  say  about 
money,  what  we  had  was  good  but  there 
didn't  seem  to  be  enough  of  it. 

I  have  before  me  a  copy  of  the  news- 
paper containing  a  story  about  our  sta- 
tion and  also  the  first  program  that  was 
broadcast  from  it.  The  story  lays  much 
stress    upon    the   "modern    equipment" 


of  our  station.  Also,  much  seems  to  be 
made  of  the  fact  that  we  were  broad- 
casting upon  a  wavelength  of  360  meters 
and  that  we  could  be  heard  within  a 
radius  of  300  miles.  The  program  reads 
as  follows: 

7  p.  m. — Baseball  results. 

7:05  p.  m. — News  brevities. 

7:20  p.  m. — Cortese  Bros,  on  harp 
and  violin. 

7:50  p.  m. — Bedtime  story. 

8:10  p.  m. — Selections  on  the  reproduc- 
ing piano. 

8:30  p.  m. — New  records  on  the  phono- 
graph. 

From  this  you  can  see  that  a  large 
part  of  our  programs  was  taken  up  with 
selections  on  the  reproducing  piano  and 
records  on  the  phonograph.  I  can  remem- 
ber working  myself  into  a  terrible  state 
of  nervousness  one  night  because  the 
music  house  which  furnished  the  piano 
rolls  and  phonograph  records  had  for- 
gotten to  change  them  and  we  had  to 
give  the  same  program  that  we  had 
broadcast  the  night  before. 

After  our  station  had  been  in  operation 
several  months,  the  other  afternoon 
newspaper  started  a  station.  They 
profited  by  our  experience.  They  fitted 
up  a  beautiful  studio  with  thick  rugs 
(Tnru  to  page  65) 


Interior  of  the  radio  broadcasting  station  at  WGY,  Schenectady,    N.   Y.,  one  of  America's  most  up-to-date  radiocasts.     Compare  this 
equipment  with  Miss  Wagner's  "up-to-date"  station  of  four  years  ago — and  note  the  advance  in  radio  during  its  comparatively  small  life. 


32 


RADIO  AGE  for  September,  1925 


What  the  Broadcasters  are  Doing. 


Radio  Age  Contest  Starts  with  Rush! 

NEW  PRIZES  ANNOUNCED 

Three  Aero  Coils  to  be  Awarded  Winner 

of  Subscription    Contest    in   September; 

Winners  of  August  Contest  to  be  Named 

in  Next  Issue 


ALTHOUGH  at  the  time  this  is 
f\  being  written  concrete  results  from 
the  prize  contest  announcement  in 
the  August  issue  have  not  fully  material- 
ized, nevertheless  we  are  banking  strong 
on  the  energy  and  persistence  of  those 
enthusiasts  who  have  started  off  on  the 
contest. 

On  account  of  the  fact  that  material  for 
publication  in  our  magazine  has  to  be  pre- 
pared so  far  in  advance,  it  does  not  seem 
possible  to  get  into  the  September  issue 
much  data  on  the  activity  of  contestants 
for  the  month  of  August.  However,  we 
will  do  our  very  best  to  print  the  results 
as  quickly  as  possible. 

As  previously  announced,  the  first 
prize  for  the  radio  fan  sending  in  the 
largest  number  of  annual  subscriptions 
during  the  month  of  August  is  a  .0005 
mfd.  Ultra-Lowloss  Condenser  made  by 
the  Phenix  Radio  Corp.  It  is  pictured 
on  page  1  of  the  August  issue  of  RADIO 
AGE.  The  second  prize  is. a  year's  sub- 
scription to  this  magazine  and  the  third 
prize  a  six  months'  subscription. 

For  September  the  first  prize  will  be 
a  set  of  three  Aero  Coils  manufactured  by 
the  Henninger  Radio  Mfg.  Co.,  of  Chi- 
cago, 111.  These  coils  are  air  spaced  and 
well  built.  The  second  and  third  prizes 
will  be  the  same  as  for  August. 

No  Summer  Slump 

THE  August  number,  which  probably 
astonished  you  with  its  vast  blue- 
print section,  marks  a  new  milestone  in 
the  journey  of  RADIO  AGE  toward 
higher  levels  in  the  radio  publication 
field.  That  number  shows  both  our 
readers  and  our  advertisers  that  the  deep 
declivity  formerly  noticed  in  Summer 
radio  has  been  bridged  and  that  instead  of 
the  proverbial  Summer  slump,  radio 
activities  go  ahead  just  the  same.  The 
bulk  of  correspondence  in  the  Dial 
Twisters  and  the  Pickup  and  Hookups 
Sections  show  that  our  readers  are  not 
allowing     Summer    static     to     interfere 


materially  with  their  pleasure.  Some  of 
the  DX  lists  sent  in  during  June  and  July 
would  have  been  considered  impossible 
two  years  ago.  The  increase  in  power  of 
the  many  stations  has  brought  the 
signal  strength  above  the  static  level. 
Everything  points  to  much  better  Sum- 
mer conditions  than  ever  before  en- 
countered. 

RADIO  AGE  has  kept  pace  and  at 
times  anticipated  these  conditions.  Since 
the  success  of  this  Summer  season  is  an 
accomplished  fact,  RADIO  AGE  is 
ready  to  go  ahead  with  its  help  in  making 
the  coming  Fall  season  the  best  that  has 
ever  been  experienced.  We  are  getting 
more  readers  every  day;  the  new -stand 
sales  are  increasing;  the  subscriptions  are 
coming  in  faster;  more  advertisers  are 
taking  advantage  of  the  wonderful 
advertising  value  of  our  columns;  alto- 
gether we  are  forging  ahead  at  an  exhilar- 
ating pace. 

Naturally,  our  present  subscribers  and 
readers  take  pride  in  the  prosperity  and 
growth  of  our  magazine,  for  it  brings 
to  them  dividends  in  the  form  of  better 
material,  quicker  access  to  technical  data; 
first  hand  news  of  the  broadcasting  sta- 
tions; and  clear  cut,  simple  and  accurate 
blueprints  from  which  even  the  rankest 
tyro  can  build  a  set.  This  pride  is  re- 
flected in  the  activities  of  our  readers  who 
are  taking  part  in  this  subscription  con- 
test with  a  view  to  winning  some  of  the 
prizes  offered  every  month. 

The   Best   Is   Coming 

IT  DOES  not  take  much  time  or 
trouble  to  round  up  a  subscriber  to 
RADIO  AGE.  The  August  issue  should 
alone  be  proof  positive  of  our  lead  in  the 
radio  publication  field,  a  lead  which  we 
intend  keeping  at  all  costs.  The  radio 
fans  deserve  the  best  in  radio  and  as  far 
as  we  are  concerned  we  are  going  to  see 
that  they  get  it. 

This  magazine  neglects  none  of  the 
classes  of  readers,  for  there  are  classes  of 


readers  after  all.  The  non-technically 
inclined  can  find  plenty  of  interest  in  the 
feature  articles.  The  tyro,  by  consulting 
our  blueprints,  may  with  ease  construct 
a  receiver  of  nearly  any  known  type ;  the 
man  who  is  unable  to  "roll  his  own"  has 
before  him  in  the  pages  of  RADIO  AGE 
a  wonderful  vista  of  the  manufactured 
sets,  the  best  the  radio  market  affords. 
The  man  interested  in  receiving  circuits 
alone  can  find  them  between  our  covers, 
while  the  transmitting  amateur,  known 
as  the  brass  pounder,  may  also  find 
solace  in  our  pages.  We  serve  all  classes 
and  ignore  none.  What  better  aim  than 
that  in  radio? 

There  is  no  excuse  for  anyone  holding 
back  from  participation  in  the  most 
popular  science  of  the  day  simply  because 
he  believes  that  tomorrow  will  bring  some 
wonderful  achievement  that  will  nullifv 
all  the  past  work.  Things  do  not.  come 
that  way  in  the  radio  field.  Ask  some  of 
the  chaps  who  have  been  in  the  game 
since  1900  and  they  can  tell  you  of  the 
years  which  it  has  taken  for  radio  to 
emerge  from'  its  chrysallis  state.  Of 
course,  rapid  strides r  are  being  made 
in  the  art ;  a  poor  art  indeed  if  no  progres 
were  made. 

But  there  would  be  just  as  much  logic 
in  refraining  from  buying  an  automobile, 
because  it  is  not  yet  equipped  with  wings, 
as  there  would  be  to  the  idea  that  you 
should  hold  back  your  radio  purchases 
for  a  time,  because  static  has  not  been 
eliminated,  or  because  you  cannot  have 
an  eight  tube  super  for  §13.45,  com- 
plete. 

We  trust  some  of  our  contestants 
may  be  imbued  with  some  of  the  enthu- 
siasm we  feel  for  the  future  of  the  radio 
art  and  our  own  magazine.  This  same 
enthusiasm  may  be  communicated  to  a 
prospective  subscriber;  the  results  will 
determine  the  depth  of  your  own  pride 
in  RADIO  AGE. 

On  the  job,  fans,  let's  see  your 
stuff. 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour  33 


Clearing  Up  Difficulties  in 

Audio  Amplifying  Circuits 

By  JOHN  B.  RATHBUN 


OUT  of  every  three  letters  received 
at  the  offices  of  RADIO  AGE,  at 
least  one  letter  reads,  "Please 
send  me  a  diagram  showing  how  to  add 
audio  amplification  to  my  present  set." 
The  audio  amplification  idea  seems  to  be 
the  most  difficult  of  all  radio  stunts  for 
the  average  novice,  and  it  is  for  this 
reason  that  I  have  decided  to  devote  this 
month's  blueprint  section  to  the  subject 
of  audio  frequency  amplification  in  its 
many  branches  and  ramifications.  With 
but  few  exceptions,  these  audio  circuits 
can  be  applied  to  all  types  of  receiving 
sets,  increasing  the  volume  and  making 
loud  speaker  operation  possible  when  the 
initial  signal  is  strong  enough  in  the 
detector  stage.  Except  for  making  weak 
signals  louder,  they  do  not  add  to  the 
distance  getting  qualities  and  therefore 
must  not  be  confused  with  radio  fre- 
quency amplification  wherein  the  ampli- 
fying tubes  are  placed  before  the  detector 
stage.  Audio  amplification  simply  in- 
creases the  sound  volume  and  does  not 
increase  the  sensitivity  of  the  receiver. 

Before  starting  out  with  a  description 
of  the  circuits,  I  wish  to  call  your  atten- 
tion to  the  fact  that  the  audio  amplifiers 
are  connected  to  the  "output"  of  the 
detector  circuit,  or  rather  to  the  phone 
posts  or  jack  of  the  detector  stage.  The 
weak  signal  from  the  detector,  that  would 
otherwise  pass  through  your  headset, 
now  passes  to  the  audio  amplifier  for 
amplification  or  "magnification."  The 
headset  is  now  transferred  from  the  old 
detector  output  posts  to  the  "output"  of 
the  audio  amplifier,  and  at  the  latter  point 
will  receive  the  same  signals  greatly  in- 
creased in  strength.  The  output  of  the 
detector  goes  to  the  "input"  of  the  am- 
plifier, and.  the  phones  or  loud  speaker  are 


Copyright:  1925 


Some  Very   Efficient 
Circuits  that  Will  In- 
crease the  Volume  in 
All  Classes  of  Sets 


then    connected    to    the    output    of    the 

amplifier. 

After  this  connection  is  made  to  the 
amplifier,  we  then  make  the  battery 
connections  to  the  amplifier  tubes  in  the 
usual  way,  and  the  job  is  completed. 
The  same  "A"  and  "B"  batteries  are 
used  for  both  the  detector  and  amplifier, 
so  that  no  great  complication  is  intro- 
duced at  this  point,  but  we  should  note 
that  the  tubes  of  the  amplifier  stages 
demand  a  higher  plate  voltage  than  is 
ordinarily  applied  to  the  detector  tube, 
so  that  an  additional  block  of  "B" 
battery  will  be  used,  connected  in  series 
with  the  first  "B"  battery  of  the  detector 
stage. 

Single  Transformer  Coupled  Stage 

T)ROBABLY  the  simplest  audio  ampli- 
-*-  fication  unit  is  the  single  tube  trans- 
former coupled  amplifier,  shown  in 
picture  form  by  Fig.  1  of*  the  blueprints. 
At  the  left,  we  have  the  radio  receiver 
unit  shown  in  dotted  lines  to  distinguish 
it  from  the  amplifier  unit,  and  in  the 
tuner-detector  receiver  is  shown  the 
single  detector  tube  socket  (D).  This 
single  "stage"  of  audio  amplification  will 
make  the  faint  signals  of  distant  stations 
much   louder   on   the   headset,    and   will 


permit  of  fairly  good  loud  speaker  volume 
on  strong  local  stations,  but  of  course  is 
not  the  equal  to  the  two  stage  amplifier 
used  on  the  larger  and  more  powerful 
radio  receivers. 

At  the  binding  posts  (pl-p2)  we  have 
the  "output"  of  the  detector  tube  (D), 
and  this  is  the  point  at  which  we  connect 
our  headset  with  the  single  tube  outfit. 
On  looking  carefully  at  the  left  diagram 
of  the  receiver,  you  will  see  that  the  post 
(pi)  connects  with  plate  binding  post  (P) 
of  the  detector  tube  socket  (D)  and  that 
the  output  post  (p2)  connects  with  the 
(B)  battery  binding  post.  These  con- 
nections are  found  on  all  single  tube 
detector  outfits  and  before  making  any 
connections  we  must  find  out  which 
output  post  goes  to  the  detector  plate 
and  which  goes  to  the  (  +  B)  post. 
Where  a  jack  is  used  for  the  output,  we 
have  two  similar  connections  to  the  jacks 
which  are  made  in  the  same  way  as  to 
the  posts. 

Now  we  move  to  the  right  and  note  the 
first  element  of  the  amplifier,  the  audio 
transformer  (AFT).  This  is  provided 
with  four  connection  binding  posts,  two 
of  which  connect  to  the  ends  of  the  prim- 
ary coil  (PRI),  and  two  of  which  are 
terminals  for  the  ends  of  the  secondary 
coil  (SEC).  The  primary  posts,  forming 
the  "input"  of  the  amplifier  stage,  are 
always  marked  (P)  and  (B).  The 
secondary  binding  posts  are  marked  (G) 
and  (A)  in  this  particular  transformer, 
but  the  lower  post  may  sometimes  be 
marked  (F)  or  ( — F)  with  some  makes. 
However,  you  may  always  be  sure  that 
the  post  (G)  forms  one  end  of  the  second- 
ary in   all  transformers. 

Now  note  carefully  the  connections 
(Turn  to  page  36) 


Blueprints  of  the  Audio  Amplifying  Circuits  on  pages  34,  35,  38  and  39. 


RECEIVER-? 


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36 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


(  Continued  from  page  33) 
made  between  the  primary  of  the  trans- 
former and  the  receiving  set.  The  trans- 
former post  (P)  is  connected  to  the  phone 
post  (pi)  which  in  turn  goes  to  the  plate 
(P)  of  the  detector  tube  (D).  The  prim- 
ary transformer  post  (B)  goes  to  the 
phone  post  (p2)  which  in  turn  goes  to  the 
(-|-B)  post  of  the  receiver.  Never  make 
the  connections  in  any  other  way.  Now 
carefully  note  that  the  (G)  post  of  the 
transformer  goes  to  the  (G)  of  the  ampli- 
fier tube  socket  (Al),  and  that  (A)  is 
connected  to  the  ( — A)  filament  battery 
line.  This  completes  the  transformer  con- 
nections, and  we  will  now  complete  the 
connections  to  the  tube  socket  (Al). 

A  separate  rheostat  (R)  or  a  fixed 
resistance  will  be  required  for  the  control 
of  the  amplifier  tube  (Al).  One  post  of 
the  rheostat  (R)  is  connected  to  the  left 
filament  post  (F)  of  the  socket,  while  the 
other  end  of  the  rheostat  goes  to  the 
( — A)  battery  post  below.  The  right 
hand  post  (F)  is  connected  directly  to 
the  (+A)  post  with  the  latter  also  con- 
nected to  the  ( — B)  battery  post  as 
shown.  With  some  makes  of  sockets,  the 
left  filament  posts  is  sometimes  marked 
( — )  or  ( — F),  while  the  right  hand  post 
may  be  marked  (+)  or  (+F).  However, 
it  is  easy  to  identify  the  filament  posts 
by  the  fact  that  they  are  opposite  the 
(G)  and  (P)  socket  connections  on  all 
standard  sockets.  With  the  "199" 
sockets  the  arrangement  is  somewhat 
different,  but  the  lettering  is  the  same; 
hence,  this  should  introduce  no  diffi- 
culties. 

Saving  Battery  Current 

AT  (Ml),  connected  to  the  amplifier 
socket  post  (P),  and  the  output  post 
(M2)  connected  with  the  (  +  B)  battery 
post,  we  have  the  connections  for  the 
phones  when  the  stage  of  amplification  is 
included.  It  is  at  this  point  that  we  get 
the  full  amplification  of  the  second  tube. 
If  we  wish  to  listen  in  on  the  detector 
tube  with  strong  signals,  with  the  ampli- 
fier tube  turned  out,  we  then  provide  the 
detector  posts  (Nl)  and  (N2)  to  which 
the  phones  are  transferred.  This  saves 
battery  current  when  strong  signals  are 
coming  in,  as  we  can  cut  out  the  amplifier 
tube,  but  the  posts  (N1-N2)  are  not  ab- 
solutely necessary. 

A  small  "C"  battery  can  be  connected 
in  the  (  —A)  line  leading  to  the  transformer 
if  desired,  and  this  is  really  of  great  ser- 
vice, as  it  clarifies  reception,  cuts  down 
the  load  on  the  "B"  battery,  and  some- 
what increases  the  volume  of  the  ampli- 
fier. I n  all  cases,  the  negative  (  — )  end  of 
the  "C"  battery  is  connected  to  the  (A) 
or  (F)  post  of  the  transformer  while  the 
plus  "C"  goes  to  the  negative  filament 
line  ( -A).  When  67.5  to  90  volts  of  "B" 
battery  are  used,  the  "C"  battery  should 
be  a  three  cell  4.S  volt  battery  of  the  very 
small  flashlight  type  or  a  standard  small 
"C"  battery  made  for  this  purpose. 
There  is  no  current  drawn  from  the  "C," 
and  it  will  last  for  many  months  without 
attention. 

Distortion,  due  to  the  audio  trans- 
former (AFT)  can  usually  be  cleared  up 
by  connecting  a  small  fixed  condenser 
(Kl)  across  the  secondary  posts  (G-A). 


This  should  not  have  a  capacity  exceeding 
0.00025  mf.  or  0.0005  mf.,  for  greater 
capacities  cut  down  the  volume.  This 
condenser  also  eliminates  many  of  the 
tube  noises  and  the  hissing  and  frying 
sounds  that  usually  are  in  evidence  when 
the  output  of  the  detector  tube  is  ampli- 
fied. 

As  a  higher  plate  voltage  is  required  for 
the  amplifier  than  with  the  detector,  we 
must  connect  in  a  second  "B"  battery 
(B2)  in  series  with  the  original  detector 
"B"  battery  marked  (Bl).  The  maxi- 
mum volume  is  attained  when  the  voltage 
applied  by  (B2)  at  the  amplifier  connec- 
tions is  90  volts. 

Two  Stages  of  Audio 

WITH  two  stages  of  audio  amplifi- 
cation, employing  two  amplifier 
tubes  and  two  audio  frequency  trans- 
formers, the  volume  is  enormously  in- 
creased over  that  obtained  by  a  single 
stage,  andloudspeaker  volume  is  had  even 
on  distant  stations.  So  great  is  the  am- 
plification  that   we  can    operate  a  loud 


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Ready  for  the 

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That  Starts  in 

September? 

Let  the  RADIO 

AGE  ANNUAL  for 

1925  be  Your 

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speaker  with  good  volume  on  local  sta- 
tions with  only  a  crystal  detector. 

The  output  of  the  detector  tube  of  the 
receiver  is  connected  to  the  input  posts 
of  the  amplifier  transformer  at  (pi)  and 
(p2)  as  described  above,  always  taking 
care  that  the  transformer  post  (P)  goes 
to  the  plate  (P)  of  the  detector  tube,  and 
that  the  (B)  post  of  the  transformer  goes 
to  the  (  +  B)  post  of  the  detector  tube. 
The  signals  from  the  detector  enter  the 
first  stage  audio  transformer  (AFT-1) 
where  the  voltage  is  increased,  and  the 
induced  current  is  then  led  to  the  first 
stage  amplifier  tube  (T-l)  where  the  first 
amplification  is  performed.  The  output 
of  the  first  stage  tube  then  goes  to  the 
second  stage  transformer  (AFT-2)  and 
thence  to  the  second  stage  tube  (T-2)  and 
to  the  output. 

A  phone  jack  (Jl)  connected  across  the 
primary  of  the  second  transformer  al- 
lows us  to  tap  in  so  that  we  obtain  one 
stage  of  amplification.  Plugging  into  the 
output  jack  (J2)  or  connecting  the  speaker 
permanently  with. the  output  posts  (Ml) 
and  (M2)  gives  us  the  total  amplification 


of  both  stages.  With  some  local  stations 
the  volume  is  too  great  with  both  stages 
running;  therefore  the  first  stage  jack 
(Jl)  is  often  very  convenient. 

A  single  rheostst  (R)  controls  both  am- 
plifier tubes.  This  is  more  economical 
and  simpler  than  when  a  rheostat  is  used 
for  each  stage,  although  the  latter  ar- 
rangement can  also  be  used.  By  similar 
cross-connections  between  the  two  stages, 
a  single  "C"  battery  is  used  for  biasing 
both  tubes.  The  fixed  bypass  condenser 
(Kl)  connects  across  the  primary  of  the 
first  stage  transformer  only,  and  is  of 
great  assistance  in  obtaining  a  clear  tone 
and  noiseless  operation.  The  value  of 
(Kl)  should  not  exceed  0.00025  mf.  or 
0.0005  mf.,  as  higher  values  deaden  the 
signals  and  also  reduce  the  volume. 
When  the  transformers  are  such  that 
there  is  little  distortion  or  noise,  then  it  is 
best  to  avoid  loss  by  omitting  (Kl)  alto- 
gether. 

At  (L)  is  shown  a  "radio  frequency 
choke"  which  does  much  to  clear  up 
noises  and  which  may  also  increase  the 
volume  by  choking  back  signals  that 
would  otherwise  pass  to  the  "B"  battery 
through  the  capacity  of  the  transformer 
primary.  This  choke  can  be  a  standard- 
choke  or  filter  coil  made  for  this  parti- 
cular purpose,  or  it  can  be  made  at  home 
by  winding  from  50  to  100  turns  of  No. 
30  D.  C.  C.  wire  on  a  one  inch  diameter 
spool  or  tube.  The  choke  is  not  absolutely 
necessary,  but  it  is  a  protection  against 
the  howling  that  sometimes  is  started  in 
the  audio  stages  by  radio  frequency  cur- 
rents. The  addition  of  a  second  radio 
frequency  bypass  condenser  (K2)  across 
the  primary  of  (AFT-1)  will  help  things 
still  further,  and  when  this  condenser  is 
installed,  it  is  often  possible  to  eliminate 
(Kl).  The  capacity  of  (K2)  is  not  critical 
and  will  range  from  0.001  mf.  to  0.0025 
mf.  according  to  the  characteristics  of  the 
transformer. 

The  ratios  of  the  transformers  now  be- 
come of  importance,  for  they  greatly  affect 
the  volume  and  clarity  of  the  reception. 
High  ratio  transformers  may  give  greater 
amplification  on  certain  notes  in  the 
musical  range,  but  they  introduce  much 
distortion  and  "razzing"  to  the  detriment 
of  the  signal  purity.  By  using  a  low  ratio 
transformer  (AFT-1)  in  the  first  stage, 
such  as  a  3  to  1,  or  4  to  1  ratio,  and  a 
higher  ratio  for  the  second  stage  (AFT-2), 
we  get  the  best  combination  of  volume 
and  tone  quality.  The  second  transfor- 
mer (AFT-2)  can  be  a  5  to  1,  or  6  to  1 
type,  but  seldom  higher  than  the  latter 
if  excessive  distortion  is  to  be  avoided. 
Having  both  transformers  of  a  3  to  1 
ratio  gives  very  good  tone  quality  but  the 
results  are  somewhat  deficient  in  regard 
to  volume. 

At  this  point  I  wish  to  call  your  atten- 
tion to  a  trouble  that  is  generally  due  to 
carelessness  in  the  manufacture  of  the 
transformers.  In  making  the  internal 
connections  of  the  transformers,  the.  as- 
semblers sometimes  reverse  the  connec- 
tions to  the  transformer  posts  and  this 
causes  a  continuous  howl  that  is  exceed- 
ingly annoying.  This  audio  frequency 
howl  can  be  located  by  touching  the 
transformer  posts  with  your  finger.  If 
the  howl  stops  when  you  touch  one  of  the 


RADIO  AGE  for  September,  1925 


posts,  you  have  located  the  transformer 
in  which  the  wires  have  been  reversed. 
The  only  remedy  will  be  to  reverse  the 
connections  to  the  primary  posts  of  that 
transformer;  that  is,  to  disconnect  the 
wire  from  the  (P)  post  and  connect  it  to 
the  (B)  post,  and  then  connect  the  wire 
formerly  attached  to  the  (B)  post  to  the 
(P)  post.  The  outside  turn  of  the  second- 
ary coil  should  always  be  the  (G)  connec- 
tion, and  if  this  is  not  the  case,  we  must 
reverse  our  outside  wiring  to  compensate 
for  the  error.  Do  not  meddle  with  the 
internal  wiring  of  the  transformer. 

Resistance  Coupled  Audio 

RESISTANCE  coupling  is  now  becom- 
ing very  popular  because  of  its  free- 
dom from  distortion  and  the  clear,  bell- 
like tones  obtained  at  all  points  in  the 
musical  scale.  The  deep  notes  of  the 
cello  are  given  an  amplification  equal  to 
the  high  pitch  of  the  flute;  a  condition 
that  does  not  always  obtain  with  many 
commercial  transformers  of  the  cheaper 
makes.  Of  course,  there  are  many  high 
grade  transformers  that  amplify  without 
much  distortion,  but  such  transformers 
are  rather  high  priced.  On  the  other 
hand,  the  resistance  coupled  amplifier  is 
open  to  the  objection  of  requiring  a  higher 
plate  voltage  for  equal  amplification  and 
usually  an  extra  tube  in  the  audio  stages 
if  this  135  volts  plate  voltage  is  not  em- 
ployed. 

In  Fig.  3  is  shown  a  typical  three  tube 
resistance  coupled  amplifier  which  gives 
a  somewhat  greater  amplification  than 
obtained  with  two  stages  of  transformer 
coupled  audio  on  90  volts  potential.  With 
two  stages  of  resistance  coupling  the 
volume  is  usually  less  than  with  trans- 
former coupling  unless  the  full  135  volts 
"B"  battery  is  used.  In  any  case,  the 
amplification  is  exceedingly  clear  and 
noiseless,  and  for  the  reason  that  the 
resistance  units  have  no  natural  period, 
the  circuit  is  not  subject  to  the  howls 
and  shrieks  sometimes  met  with  in 
transformer  coupled  audio  stages. 

The  plate  current  from  the  "B"  battery 
is  fed  to  each  tube  through  the  high  resis- 
tance units  or  "resistors"  shown  at  (rl- 
r2-r3),  one  resister  being  connected  to 
each  plate.  The  amplification  is  due  to 
the  drop  of  potential  over  these  resis- 
tances when  variations  in  the  plate  cur- 
rent take  place,  and  as  this  drop  is  exactly 
proportional  to  the  plate  current  regard- 
less of  the  frequency,  all  notes  in  the 
musical  scale  are  equally  amplified.  This 
is  truly  straight  line  amplification.  The 
fixed  coupling  condensers  (K1-K2-K3) 
are  used  to  keep  the  positive  "B"  po- 
tential off  the  grids  of  the  tubes.  The 
values  of  the  resistors  and  condensors  are 
given  on  the  blueprints. 

As  a  negative  bias  must  be  given  to  the 
grids  of  the  tubes_for  proper  audio  fre- 
quency amplification,  each  grid  is  sup- 
plied with  a  grid  leak  as  at  (GL1-GL2- 
GL3),  these  leaks  connecting  with  the 
(—A)  line  of  the  battery  circuit.  The 
values  are  rather  critical  and  the  units 
shown  in  the  blueprints  should  be  closely 
followed  for  the  best  results.  Connec- 
tion to  the  detector  stage  is  made  by  the 
usual  input  posts  (pl-p2)  at  the  left,  but 
unlike    the    case    with    the    transformer 


coupled  stages,  it  does  not  matter  which 
post  goes  to  the  detector  plate  or  plus 
"B"  post. 

As  supplied  to  the  market,  the  resistors 
and  grid  leaks  are  of  the  cylindrical  type 
mounted  in  spring  clips  so  that  they  can 
easily  be  changed  in  experimenting  and 
adjusting  the  circuit.  The  arrangement 
can  be  made  very  compact  and  there  is  a 
complete  absence  of  interstage  coupling 
by  stray  magnetic  fields,  no  matter  how 
close  together  the  resistances  may  be 
packed.  The  resistors  can  be  purchased 
separately  and  mounted  on  a  bakelite 
baseboard  or  they  may  be  mounted  in  the 
convenient  bases  specially  prepared  for 
this  purpose  by  our  advertisers. 

To  complete  the  cartridge  construction, 
I  have  shown  the  "amperites"  marked  (a) 
which  are  used  for  the  control  of  the  fila- 
ment current.  The  tubes  are  not  critical 
to  rheostatic  control  and  therefore  these 
fixed  filament  control  devices  can  be  used 
to  great  advantage  instead  of  the  usual 
rheostats.  When  the  amperites  are  used, 
a  battery  switch  (SW)  must  be  used,  but 


RADIO  AGE 

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Magazine  to  Publish 

a  Complete 

Blueprint  Section 

Every  Month. 

For  the  Best 

in  Radio,  You  Should 

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RADIO  AGE 
And  Be  Up-To-Date. 

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(See  Coupon  on  page  60) 


as  this  is  also  desirable  with  rheostats,  it 
offers  no  special  complication  or  expense. 
Biasing  the  grids  by  a  "C"  battery  adds 
greatly  to  the  volume  and  tone,  just  as  it 
does  with  transformer  coupled  amplifiers. 
It  stabilizes  the  grids  of  the  tubes,  cuts 
down  the  "B"  battery  consumption  and 
in  many  ways  is  a  very  desirable  addition 
to  the  circuit.  In  Fig.  4  we  show  a  resis- 
tance coupled  amplifier  biased  by  the  "C" 
battery  connected  to  the  grid  leaks  of  the 
various  tubes.  The  negative  potential 
imposed  on  the  grids  causes  the  tube 
amplification  factor  to  follow  the  same 
straight  line  gradient  as  the  drop  of 
potential  over  the  resistors;  hence,  we 
have  the  utmost  in  tone  purity  and  a  con- 
siderable effect  on  tube  stability.  Almost 
any  voltage  between  90  and  135  volts  will 
produce  terrific  volume  when  biased  in 
this  way,  and  without  any  danger  of  the 
tubes  "flopping." 

Audio  Amplification  "De  Luxe" 

IN  spite  of  the  refinements  mentioned 
in  the  foregoing,   a  further  improve- 
ment can  be  made  in  the  audio  stages 


The  Magazine  of  the  Hour  3  7 

which  will  attain  a  natural  quality  of 
tone  as  yet  unapproached  by  any  audio 
amplifier  described.  We  can  obtain  win- 
dow rattling  volume  without  the  slightest 
distortion,  outside  of  the  distortion  in  the 
horn  itself,  by  avoiding  an  overload  on 
the  last  tube  of  the  amplifier.  With  two 
or  three  stages,  the  last  stage  tube  is 
worked  up  to  the  limit  on  strong  incom- 
ing signals,  and  as  a  result  the  tube  is  so 
near  its  saturation  point  that  it  does  not 
respond  properly  to  the  tone  gradations 
imposed  on  its  grid. 

In  Fig.  4  is  shown  the  improved  audio 
frequency  amplifier.  The  third  stage  is 
a  transformer  coupled  stage  in  which  a 
low  ratio  transformer  is  employed.  This 
transformer  is  one  of  the  large  core  type 
now  placed  on  the  market  by  a  number  of 
manufacturers  which  introduces  prac- 
tically no  distortion  on  any  ordinary 
sound  frequency.  The  first  two  stages 
are  resistance  coupled  biased  stages.  To 
avoid  overloading  the  last  tube,  two 
tubes  are  connected  in  parallel  in  the  last 
stage,  thus  making  four  tubes  in  all. 
The  last  two  tubes  (T-3)  and  (T-4)  are 
coupled  together,  plate-to-plate  and  grid- 
to-grid,  so  that  in  effect  they  are  like  a 
single  tube.  To  fully  appreciate  the  ad- 
vantages of  this  amplifier,  you  must  hear 
it  in  operation. 

The  resistance  stages,  together  with  the 
transformer  coupled  stage,  just  seem  to 
afford  the  proper  balance  and  give  all  of 
the  amplification  that  can  be  desired  even 
for  out-of-door  speakers  or  large  halls. 
Even  with  forced  amplification,  the 
parallel  tubes  function  perfectly  without 
introducing  "mush"  and  there  seems  to 
be  no  limit  to  the  proper  straight-line 
functioning  of  the  resistor  and  transfor- 
mers. It  is  more  expensive  than  the  usual 
layout,  but  then  we  must  always  expect 
to  pay  the  price  for  perfect  reception. 

As  both  the  tubes  (T-3)  and  (T-4)  must 
be  perfectly  synchronized,  it  will  be  neces- 
sary to  shift  the  tubes  about  or  use 
matched  tubes  so  that  they  will  work 
together  perfectly.  It  is  also  necessary 
to  carefully  adjust  the  filament  current 
to  these  tubes  so  that  they  will  match 
under  all  operating  conditions.  All  tubes 
are  biased  by  a  "C"  battery  or  rather  by 
two  "C"  batteries  so  that  they  will  have 
perfect  straight  line  characteristics 
throughout  their  range  and  also  to  re- 
duce the  "B"  battery  consumption.  One 
"C"  battery  is  used  for  the  resistance 
coupled  stages  and  a  second  "C"  for  the 
parallel  connected  transformer  coupled 
stages. 

In  general,  this  adds  two  tubes  to  a  re- 
ceiver already  equipped  with  two  stages 
of  audio.  Thus,  a  conventional  five  tube 
radio  frequency  receiver  will  have  seven 
tubes  when  equipped  in  this  manner;  an 
added  expense,  but  well  worth  it  when 
the  receiver  is  ordinarily  worked  at  a 
great  volume.  The  primary  of  the  trans- 
former is  equipped  with  the  choke  coil  (L) 
for  reasons  already  explained,  and  bypass 
condensers  of  the  capacity  noted  on  the 
drawing  are  also  added  to  insure  purity 
of  tone.  The  casing  of  the  transformer 
should  be  thoroughly  grounded  and  it 
should  be  installed  well  away  from  the 
other  tubes  and  apparatus  so  that  there 
(Turn  to  page  40) 


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40 


RADIO  AGE  for  September,  1925 


( Continued  from  page  37) 
will  be  no  danger  from  stray  fields. 
A  wet  "B"  battery  is  practically  a 
necessity  for  the  supply  of  plate  current 
to  so  many  tubes.  A  dry  "B"  of  the 
largest  size  will  soon  become  exhausted 
if  the  set  is  used  to  any  extent.  Primarily 
this  is  intended  for  use  in  halls,  dancing 
schools  and  similar  places  where  con- 
tinuous service  and  heavy  duty  are  the  rule. 
For  home  use,  the  small  "199"  tubes  will 
give  excellent  service,  but  they  must  be 
used  with  a  storage  battery  in  place  of 
the  more  usual  dry  cells. 

For  the  best  results  an  independent 
"B"  battery  should  be  used  for  the  four 
tube  audio  amplifier  with  an  independent 
"B"  battery  for  the  detector  and  radio 
frequency  tubes.  This  is  not  absolutely 
necessary,  but  it  is  desirable.  With  the 
same  "B"  for  both  the  detector  and  audio 
amplifier,  there  is  always  some  radio  fre- 
quency current  flowing  in  the  audio 
stages  which  may  cause  disagreeable  oscil- 
lations to  take  place  in  the  last  stages. 
This  can  be  avoided  to  some  extent  by 
placing  a  radio  frequency  choke  in  the 
(-(-B)line  of  the  common  "B"  battery,  but 
even  then  independent  "B"  batteries  are 
the  best. 

Audio  Amplifier  Troubles 

The  following  troubles  apply  to  all 
amplifier  circuits  as  noted,  and  the  data 
will  be  of  service  to  those  who  experience 
trouble  at  this  point. 

1.  A  loud  continuous,  thin  humming 
noise  may  be  due  to  an  open  connection 
in  the  grid  circuit  of  the  tubes,  or  to  poor 
contact  between  the  tube  prongs  and 
socket  springs. 

2.  A  defective  transformer  winding 
may  cause  the  humming  above  or  it  may 
cause  a  regular  popping,  knocking  noise. 
Test  out  each  transformer  before  instal- 
ling it  by  connecting  your  head  set  and  a 
dry  battery  in  series  with  each  of  the  coils, 
primary  and  secondary,  and  listening  for 
the  sharp  click  that  denotes  an  unbroken 
coil. 

3.  Howling,  shrieking  or  mushed  up 
and  distorted  signals  can  usually  be  cured 
by  applying  a  fixed  condenser  across  the 
primary  or  secondaries  of  the  transfor- 
mers.   The  values  of  these  condensers  will 

'depend  upon  the  make  and  type  of  the 
transformers  and  must  be  determined  by 
experiment.  Try  connecting  the  plate  (P) 
of  the  last  tube  to  the  (  —A)  line  through 
a  0.002  mf.  or  0.006  mf.  fixed  condenser. 
i.  A  crackling  crashing  noise,  much 
like  static,  is  frequently  caused  by  an 
exhausted  "B"  battery.  Better  form  the 
habit  of  testing  these  batteries  occasional- 
ly with  a  voltmeter. 

5.  A  continuous  howl  that  persists  re- 
gardless of  the  signals  passing  through  the 
set,  can  be  cured  by  reversing  the  primary 
wires  of  the  first  transformer.  This  has 
been  suggested  before.  An  "audio  howl" 
can  be  detected  by  touching  the  trans- 
former posts  with  the  fingers.  When  the 
howl  stops  on  touching  the  post  lightly, 
reverse  the  leads  of  that  transformer  as 
above. 

6.  A  ringing  sound  caused  by  striking 
the  set  may  be  due  to  imperfect  socket 
contacts.  Bend  up  the  springs  so  the>> 
bear  with   more  force  against  the  tube 


prongs  or  else  clean  the  socket  springs 
with  a  piece  of  sand  paper.  Dry  battery 
tubes,  such  as  the  WD-12  or  the  "199" 
will  always  ring  or  roar  when  vibrated. 
These  tubes  should  always  be  provided 
with  rubber  cushioned  shock  absorbers 
to    eliminate    the    so-called    microphonic 


Tube  Ballot  Results  and  What 
They  Mean 

By  Roscoe  Bundy 

WHILE  our  readers  responded  nobly 
in  the  "Tube  Ballot  Contest" 
started  in  the  July  issue  of  RADIO  AGE, 
yet  we  would  like  to  have  a  few  more 
expressions  of  opinion  on  the  subject  of 
the  number  of  tubes  that  you  prefer  in 
a  radio  receiving  set.  The  more  answers, 
the  more  representative  will  be  the  choice 
and  the  nearer  we  will  come  to  the  truth. 
To  form  any  opinion  on  this  subject, 
we  should  have  at  least  500  replies  and 
we  are  still  a  long  way  from  this  number. 

When  I  first  started  this  contest,  I 
rather  had  doubts  as  to  the  honesty  of 
the  replies,  but  since  the  ballots  have 
started  coming  in  I  believe  that  they 
actually  express  the  correspondent's  true 
opinion  on  the  subject.  If  they  "could 
only  afford  a  three  tube  set,"  they  said  so 
frankly  and  without  any  attempt  at 
"four-flushing."  This  restores  one's 
confidence  in  human  nature.  The  fact 
that  the  four  tube  set  stands  high  in  the 
regard  of  the  radio  public  is  quite  inter- 
esting to  me,  particularly  as  it  over- 
shadows the  assumed  leadership  of  the 
five  tube  receiver.  If  we  had  some  more 
votes  we  could  settle  down  on  a  more 
definite  conclusion  as  to  the  relative 
popularity  of  the  various  circuit  com- 
binations. 

Up  to  date,  the  votes  give  the  follow- 
ing   results: 

Summary  of  Results 

Two  tubes 00.00  Per  cent 

Three  tubes 10.00  Per  cent 

Four  tubes 40.00  Per  cent 

Five  tubes .  . 25.00  Per  cent 

Six  tubes 15.00  Per  cent 

Seven  tubes 5.00  Per  cent 

Eight  tubes 5.00  Per  cent 

Total 100.00  Percent 

Our  old  fiiend,  the  three  tube  regener- 
ative, still  has  its  adherents,  but  so  far 
we  have  had  no  entries  on  the  one  or  two 
tube  receiver,  either  of  the  regenerative 
or  reflex  type.  The  six,  seven  and  eight 
tube  super-hets  have  many  friends,  but 
of  course  this  appeals  to  rather  a  limited 
field,  principally  because  of  the  cost. 
One  remarkable  point  in  the  compilation 
is  the  popularity  of  the  four  tube  reflex, 
which  far  overshadows  the  popularity 
of  the  five  tube  radio  frequency  receiver. 
Whether  this  is  due  to  our  striking  a  big 
bunch  of  reflex  fans,  or  whether  it  is 
really  representative  of  popular  opinion, 
it  is  difficult  to  say,  but  the  ballots  count 
out  in  this  way  in  any  case.  Is  the  five 
tube  receiver  slipping  or  are  the  four  tube 
enthusiasts  recruited  from  the  ranks  of 
former  one,  two  and  three  tube  owners? 

R.   C.   Audio  is  Popular 

ANOTHER  interesting  fact  was  dis- 
covered, and  that  was,  that  re- 
sistance coupled  audio  stages  have  some 
very  warm  adherents.  Those  of  the 
voters  who  had  actual  experience  with 
resistance  coupling  were  enthusiastic, 
and  one  or  two  devoted  several  pages  of 


The  Magazine  of  the  Hour 

comments  on  this  subject,  which  were 
highly  interesting  and  illuminating.  We 
invite  more  letters  on  resistors,  letters 
giving  results  in  full  detail,  and  particu- 
larly information  on  the  application  of 
resistance  coupling  to  reflex  circuits. 
We  rather  suspect  that  J.  H.  L.  of  De- 
troit is  one  of  these  professional  kidders 
that  we  meet  with  now  and  again.  His 
choice  was  a  fifteen  tube  resistance 
coupled  super-heterodyne!     Good  night! 

Six  tube  receivers  show  up  fairly  well, 
but  not  so  prominently  as  I  once  thought 
they  would.  So  many  different  combina- 
tions of  coupling  are  possible  with  this 
number  of  tubes  that  it  is  impossible  to 
analyze  the  votes  here,  but  it  goes  to 
show  that  six  tubes  mark  the  practicable 
limit  for  quantity  production,  no  matter 
what  the  circuit  may  be.  Of  the  six  tube 
votes,  the  greater  number  specified  six 
tube  super-hets  with  only  a  sprinkling 
of  radio  frequency  circuits,  and  in  nearly 
every  case  "199"  tubes  were  chosen  for 
the  six  tube  outfits.  The  importance  of 
battery  current  consumption  is  being 
realized,  and  when  we  get  over  four  tubes, 
we  start  to  notice  a  prevalence  of  "199" 
tube  requests.  • 

With  the  "199"  type  tube,  a  four  tube 
receiver  takes  4x0.06-0.24  ampere,  or 
a  little  less  than  the  rated  economical 
capacity  of  a  No.  6  dry  cell  "A"  battery. 
Three  such  dry  cells  in  series  give  suffi- 
cient voltage  and  current  for  the  opera- 
tion of  a  "199"  tube  receiver,  and  this 
may  be  one  reason  for  the  popularity 
of  this  type  of  radio  set.  It  has  good 
performance  and  yet  is  within  the  con- 
fines of  a  portable  set  in  size.  Another 
arrangement,  aside  from  the  four  tube 
reflex,  is  the  three  tube  regenerative 
preceded  by  a  stage  of  radio  frequency 
amplification.  The  latter  arrangement 
also  seems  to  be  in  accord  with  the  ideas 
of  many  of  our  readers. 

There  are  five  tube  receivers  employ- 
ing "199"  tubes,  but  they  are  not  repre- 
sentative of  tnis  class.  The  great  ma- 
jority use  two  stages  of  radio,  detector 
and  two  stages  of  audio  with  all  tubes 
of  the  201A  type.  Such  an  arrangement 
gives  good  volume  and  distance,  and 
with  a  storage  "A"  battery  is  economical 
to  run,  but  there  seems  to  be  no  real 
reason  why  it  cannot  also  be  produced 
for  use  with  "199"  tubes,  for  the  current 
consumption  of  all  five  tubes  will  be  only 
0.30  ampere,  or  a  little  more  than  the 
rated  economical  load  for  a  series  of  No. 
6   dry   cells. 

When  we  get  to  the  city  radio  owner, 
where  there  are  many  powerful  local 
stations,  selectivity  becomes  the  most 
important  factor.  It  does  no  good  to 
have  a  receiving  set  of  tremendous 
amplifying  power  and  sensitivity  unless 
the  tuning  is  sharp  enough  to  let  us  slide 
out  through  local  broadcasting  waves. 
As  one  of  our  readers  states,  "If  my  three 
tube  set  gives  perfectly  satisfactory  loud 
speaker  volume  on  locals,  then  why 
should  I  employ  a  five  tube  set  unless 
the  'five'  tunes  sharp  enough  to  get 
through  the  local  stations?  If  neither 
set  is  selective  to  get  out  of  town,  then 
common  sense  tells  me  that  the  three 
tube  set  is  the  logical  answer  for  the  city 
dweller." 

In  Chicago,  with  its  fifteen  local  sta- 
tions, this  comes  nearly  to  being  the 
truth,  for  it  is  seldom  that  we  can  get 
any  real  distance  this  Summer  with  any 
sort  of  set  with  four  or  five  stations  on 
at  one  time,  so  why  use  a  five  tube  re- 
ceiver that  will  accomplish  no  more  than 
a   three   tuber? 

(Turn  to  page  61) 


RADIO  AGE  for  September,  1925 

What's  All  This 

STATIC 

for? 


What  the  Broadcasters  are  Doin° 


41 


?~r. 


Prominent  Engineers  Set  Out  for  Radio 
"Dead  Spots"  to  Gather  Valuable  Scien- 
tific Data;  To  Carry  a  250-Watt  Station 


IT  has  been  pretty  generally  conceded 
throughout  the  country  that  this 
has  been  a  real  "static  Summer." 
Of  coarse,  the  super-power  stations  have 
been  a  boon  to  reception,  using  their  in- 
creased wattage  to  pierce  the  static  belt 
that  appeared  late  in  May  and  was  still 
going  strong   in   August. 

However,  all  the  radiocasters  were  not 
super-power  stations,  and  the  smaller 
ones  had  to  content  themselves  with 
being  heard  over  a  range  of  only  a  few 
hundred  miles.  In  other  words,  the  radio 
science  seems  to  be  no  farther  advanced 
in  conquering  static  this  season  that  it 
was  a  few  years  ago. 

While  Mac  Millan  is  cruising  the  Arctic 
and  attempting  to  establish  voice  com- 
munication with  American  amateurs  dur- 
ing the  daytime,  an  energetic  pair  of 
Chicago  radio  engineers  are  being  original 
in  another  way;  they  have  set  out  for  the 
hot  spots  of  America  in  an  attempt  to 
establish  clear  broadcast  reception  at 
night-time,  in  those  portions  of  America 
where  it's  always  warm  and  where  static 
never  ceases. 

Off  for  the  "Dead  Spots" 

'  I  ^HESE  two  engineers,  Harvey  T. 
■*■  Kelley  and  H.  Frank  Hopkins,  built 
themselves  a  broadcasting  station  last 
month  and  are  now  on  their  way  to  the 
West;  Arizona,  the  Great  American 
Desert,  New  Mexico,  and  other  localities 
where  radio  "dead  spots"  abound  and 
where  the  natives  who  are  radio  fans 
(and  there  aren't  many  yet),  have  to 
content    themselves    with    listening    to 


stations  within  a  radius  of  200  miles;  and 
it  is  safe  to  say  there  are  not  many  sta- 
tions within  that  range  when  you  get 
out  in  the  desert  territory. 

Financed    by    leading    scientific    and 
manufacturing  agencies,  Mr.  Kelley  and 


The  engineers  will  take   with  them  a  250- 
walt  portable  broadcasting  station  very  sim- 
ilar to  the  model  shown  above. 


Harvey  T.  Kelley,  Assoc,  I.  R.  E.,  and 
one  of  the  engineers  on  this  interesting 
trip,  is  shown  above.  At  the  left  is  a 
scene  from  one  of  the  typical  canyons  in 
California,  4000  feet  high,  where  the  ex- 
pedition intends  to  pause  for  extensive 
tests.  This  region  is  known  as  a  "dead 
spot"  for  radio  reception. 


Mr.  Hopkins  set  out  with  one  avowed 
purpose;  to  find  out  whether  it  is  possible 
in  this  world  to  develop  a  receiver  that 
will  pierce  static,  or  at  least  minimize  it. 
If  that  is  impossible,  they  hope  to  learn 
just  what  circuit — not  necessarily  what 
set — performs  best  under  such  adverse 
conditions  as  they  expect  to  encounter. 
It  will  take  time,  patient  research  and 
miles  of  weary  travel  to  determine  these 
objectives;  but  once  discovered,  they 
should  be  of  invaluable  aid  to  the  radio 
world. 

Their  travels  will  take  them  into  the 
most  beautiful  mountain  and  desert 
countries  of  Western  America.  The 
portable  broadcasting  station  is  one  of 
the  most  efficient  of  its  kind  ever  built, 
containing  all  the  latest  developments  in 
broadcast  transmission.  Already  it  has 
been  tested  with  amazing  results  insofar 
as  quality,  distance  and  modulation  are 
concerned. 

Several  scientific  clubs  have  announced 
their  intention  of  recording  the  results  of 
this  research  trip  in  their  annual  reports, 
while  many  Chicago  and  outlying  broad- 
casting stations  will  broadcast  the  results 
of  the  trip  as  it  progresses,  even  attempt- 
ing communication  with  the  engineers 
from  time  to  time. 


42 


RADIO  AGE  for  September,  1925 


All  Set  for  New  York 
Radio  Fair 

NEW  YORK. — In  the  greatest  city 
and  in  the  largest  hall  in  the  world, 
the  people  of  the  most  densely  populated 
and  prosperous  region  and  thousands 
from  distant  points  will  pay  tribute  to 
the  most  marvelous  of  inventions,  Radio, 
on  the  occasion  of  the  second  Radio 
World's  Fair,  September  14  to   19. 

Who,  a  decade  ago,  dreamed  of  the 
spectacle  that  will  greet  the  visitors  to 
this  tremendous  exhibition?  Here  will 
be  shown  a  thousand  different  concep- 
tions of  that  mysterious  assortment  of, 
wires  and  tubes  that  is  revolutionizing 
the  world  in  the  education  and  enter- 
tainment it  is  daily  bringing  to  enthus- 
iastic millions, — all  manner  of  receiving 
sets,  from  the  most  expensive,  in  master- 
pieces of  the  cabinet  makers'  art  to  the 
little  crystal  sets,  hardly  bigger  than  a 
finger,  yet  large  enough  to  stir  the  pride 
and  imagination  of  many  a  future  great 
in  the  field  of  wireless  engineering. 

It  is  an  evidence  of  radio's  unparalleled 
growth  that  the  management  of  the 
World's  Fair  had  to  engage  the  258th 
Field  Artillery  Armory,  a  Titan  of  space, 
the  auditorium  of  auditoriums,  in  order 
that  these  exhibits  might  be  housed  in 
adequate  and  attractive  fashion, — and 
all  will  be  on  a  single  floor.  Last  year 
Madison  Square  Garden,  of  lamented 
memory,  was  not  big  enough,  so  the 
Sixty-ninth  Regiment  Armory  had  also 
to  be  reserved,  and  now,  in  what  will  be 
the  greatest  year  of  radio  development, 
five  Madison  Square  Gardens  in  one, — 
the  size  of  the  Field  Artillery  Armory — 
have  to  be  used.  As  a  result,  the  patrons 
will  view  an  amazing  picture,  a  seemingly 
endless  sweep  of  handsomely  decorated 
booths,  flashing  lights,  and  fluttering 
flags,  while  music  is  played  by  a  leading 
band  and  comes  through  a  series  of  loud 
speakers  from  broadcasting  stations  near 
and    far. 

And  right  in  the  center,  in  a  glass- 
enclosed  room,  will  be  seen  a  modern 
broadcasting  room,  from  which  will  be 
sent  before  the  eyes  of  the  public,  brilliant 


programs  of  vocal  and  instrumental 
music  as  a  daily  afternoon  and  evening 
compliment  to  the  absent  fans  of  radio- 
dom,  some  of  whom  may  be  listening  in 
a  thousand  miles  away,  catching  the 
spirit  of  the  occasion  but  bemoaning  their 
inability  to  view  the  row  upon  row  of 
new  sets,  loud  speakers,  and  the  various 
parts  that  go  into  the  making  of  receivers. 

Perhaps  some  of  the  music  will  reach 
foreign  shores,  for  that  would  be  appro- 
priate, indeed,  as  foreign  inventors  will 
be  represented  with  their  devices,  about 
which  little  is  being  said  now  but  about 
which  much  may  be  stated  when  the 
story  of  the  science's  progress  is  being 
written.  Japan  and  England,  in  addi- 
tion to  the  leading  manufacturers  of 
America,  will  furnish  exhibits,  and  more 
reservations  from  foreign  shores  are 
being  made. 

Befitting  the  international  significance 
of  the  exposition  and  particularly  in  the 
light  of  radio's  influence  as  a  world  factor 
in  the  cause  of  harmony  and  understand- 
ing, the  fair  will  open  with  the  greetings 
of  high  officials  from  twenty  countries, 
which  messages  will  be  flashed  through 
the  ether  as  the  doors  are  opened.  These 
expressions  frrom  abroad  will  emphasize 
the  service  that  radio  is  already  render- 
ing to  mankind. 

Public  presentations  of  prizes  to  the 
leading  announcers,  to  popular  enter- 
tainers, and,  above  all,  to  America's 
Miss  Radio,  whoever  she  may  be,  will 
attract  applause  from  watching  thous- 
ands. "Miss  Radio"  is  the  girl  fan  of 
the  United  States  who  writes  the  best 
letter  about  her  experiences  in  radio 
reception  and  gives  the  best  log  of  sta- 
tions. As  soon  as  this  contest  was  an- 
nounced, the  directors  of  the  World's 
Fair  learned  that  the  country  was  cer- 
tainly filled  with  feminine  devotees  of 
radio,  and  the  idea  of  such  a  feature  to 
the  exposition  aroused  their  commenda- 
tion. "Miss  Radio"  will  be  the  guest 
of  the  management  in  New  York  during 
the   exhibit. 

The  Radio  World's  Fair  headquarters 
are  at  1475  Broadway,  with  U.  J.  Herr- 
mann as  managing  director. 


The  Magazine  of  the  Hour 

Now  Comes  the  Pedigreed 
Radio  Tube 

TPHE  buying  of  radio  tubes  has  been  ac- 
-*-  companied  by  an  almost  complete  ab- 
sence of  exact  data  on  individual  tube 
characteristics.  Those  who  required 
matched  tubes,  or  whose  sets  would  not 
function  properly  unless  tubes  were  shifted 
or  juggled  from  one  socket  to  another,  as 
well  as  the  thousands  who  have  bought 
many  tubes  in  order  to  get  a  few  good 
ones,  will  welcome  the  news  that  it  is 
now  possible  to  obtain  tubes  accompanied 
by  individual  characteristic  curves. 

A.  J.  Musselman,  well  known  Chicago 
inventor  and  radio  engineer,  working  in 
conjunction  with  the  Van  Home  Company 
and  its  laboratories,  Franklin,  Ohio,  has 
brought  out  a  certified  tube  which  is  not 
only  superior  as  to  manufacturing  details, 
but  which  carries  with  it  this  character- 
istic curve  or  "pedigree."  The  curve  is 
packed  with  the  tube  at  the  factory,  and 
is  sealed  into  the  carton,  so  that  if  the  seal 
is  unbroken  the  buyer  may  be  sure  he  has 
a  perfect  tube,  whose  curve  gives  all  of  the 
essential  details  of  the  operating  char- 
acteristics. The  readings  on  the  curve 
are  above  the  standard  set'  by  leading 
radio  engineers  on  high  grade  tubes. 


Uncle  Sam  Coil  for  Low 
Wave  "Bugs" 

A  recent  addition  to  the  line  for  the 
benefit  of  fans  who  desire  to  tune  in  the 
lower  wavelength  stations  and  the  ama- 
teurs has  been  made  by  the  Uncle  Sam 
Electric  Co.,  214  E.  Sixth  St.,  Plainfield, 
N.  J.,  in  announcing  their  Uncle  Sam 
low  wave  coil. 

With  a  .0005  mfd.  variable,  the  coil 
will  tune  from  37  to  150  meters.  It  is 
2  7-8  inches  by  2  1-2  inches  in  size  and 
well  built,  usingthepopularspace  winding. 

This  coil  has  been  tested  in  the  RADIO 
AGE  institute  and  was  found  to  be 
satisfactory. 


End  your  Radio  Troubles  for  30c  in  Stamps 

We  have  laid  aside  a  limited  number  of  back  issues  of  RADIO  AGE  for  your  use.  Below  are  listed  hookups  to  be  found 
in  these  volumes.  Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired.  The  supply  is  limited,  so  enrich  your 
store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 

September,  1924 


January,  1924 

— Tuning  Out  Interference — Wave  Traps — Eliminators 

— Filters 

— A  Junior  Super-Heterodyne. 

— Push-Pull  Amplifier. 

— Rosen  bloom  Circuit. 

March,  1924 

— An  Eight-Tube  Super-Heterodyne. 

— A  simple,  low  loss  tuner. 

— A  Tuned  Radio  Frequency  Aplifier. 

— Simple  Reflex  Set. 

April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated). 

— A  Ten  Dollar  Receiver. 

— Anti-Body  Capacity  Hookups. 

— Refiering  the  Three-Circuit  Tuner. 

— Index  and  first  two  installments  of  Radio  Age  Data  Sheets. 

May,  1924. 

— Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

— Important  Factors  in  Constructing  a  Super-Heterodyne. 

— A  Universal  Amplifier. 

— A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 

— Radio  Age  Data  Sheets. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 

— Operating  Detector  Tube  by  Grid  Bias. 

— A  Three-Tube  Wizard  Circuit. 

— Data  Sheets. 

August,  1924 

— Breaking  Into  Radio  Without  a  Diagram. 

— The  English  4-EIement  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 

RADIO  AGE,  INC., 


— How  careful  Mounting  Will  Improve  Reception. 

— One  Tuning  Control  for  Hair's  Breadth  Selectivity. 

— Four  Pages  of  Real  Blueprints  of  a  New  Baby  Heterodyne 

and  an  Aperiodic  Variometer  Set. 
— Data  Sheets. 

October,  1924 

— An  Easily  Made  Super-Het. 
— Two  Radio  and  Two  Audio  for  Clear  Tone. 
— A  Simple  Regenerative  Set. 
—The  Ultradyne  for  Real  DX. 

— Real   Blueprints   of  a  3-Tube   Neutrodyne   and  a   Midget 
Reflex  Set. 

November,  1924 

— Blueprints  of  a  Single  Tube  Loop  Set  and  a  Capacity  Feed- 
back Receiver. 
— A  3-Tube  Low  Loss  Regenerator. 
— Mastering  the  3- Circuit  Tuner. 

December,  1924 

— Blueprints  of  a  New  8-Tube  Super-Heterodyne. 
— How  to  Make  a  Receiver  that  Minimizes  Static. 
— A  Trans-Atlantic  DX  Receiver. 

— How  to  Make  a  Home  Made  Battery  Charger  and  a  Loud 
Speaker  at  a  Small  Cost. 

January,  1925 

— A  Reflexed  Neutrodyne. 
— A  Six  Tube  Super-Het. 
— An  Efficient  Portable  Set. 
— A  Tuned  Plate  Regenerator 
— Making  a  Station-Finder. 

February,  1925. 

— A  Sure  Shot  Super-Het. 

— A  Three  Circuit  Regenerator. 

— A  Real,  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex. 


March,  1925. 

— A  Permanent  Sup-Het. 

—A  5-Tube  R.  F.  Receiver. 

— How  to  Wind  Low  Loss  Coils. 

— A  Short  Wave  Receiver. 

— Blueprints  of  a  Two-Tube  Ultra  Audion  and  a  Regenerativ 
Reflex. 

April,  1925 

—A  3-Tube  Portable  Set. 

— "B"  Voltage  from  the  A.  C.  Socket. 

— An  Amplifier  for  th  3-Circuit  Tuner. 

— Blueprints  of  a  Five-Tube  Radio  Frequency  Receiver. 

May,  1925. 

— A  "Quiet"  Regenerator. 

— A  Power  Supply  Receiver. 

— How  to  Make  a  Tube-Tester. 

— A  Unique  Super-Het  and  an  Improved  Reinarts. 

— A  Six  Tube  Portable  Receiver  Illustrated  with  Blueprints. 

June,  1925. 

— Reducing  Static  Disturbances 

— A  Seven-Tube  Super-Heterodyne. 

—The  Double  Grid  Tube  in  Ordinary  Sets. 

— Browning-Drake  Receiver. 

— Overcoming  Oscillations  in  the  Roberts  Receiver. 
— An  Ideal  Set  in  Practical  Form. 
— Soldering  Secrets. 
July,  1925 

— Learning  Tube  Characteristics. 
— How  Much  Coupling? 
—The  Six-Tube  Super-Autodyne. 
— A  Simplified  Portable  Super-Het. 
— Blueprints  of  Conventional  Radio. 
— Symbols  and  Crystal  Detector  Circuit. 
August,  1925 — 50c  per  copy 
— How  to  Attain  Smooth  Tuning. 
— Alternating  Current  Tubes. 
— Deciding  on  a  Portable  Super — 

— And  a  big  60-page  blueprint  section,  in  which  is  contained 
blueprints  of  all  the  basic  circuits  from  which  all  radio 
hookups  have  been  developed  since  the  birth  of  Radio. 


500  N.  DEARBORN  ST.,  CHICAGO 


RADIO  AGE  for  September,  1925 


^  IPxaJsL  ~  xxp^ 


The  Magazine  of  the  Hour  43 


czrii 


Hoolc^\xp^ 

npHE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  is 
■*■_  contributed  by  ourreaders.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking.  ; 


Conducted  by  Fred  Hill 

WITH  the  departure  of  the  Mac- 
Millan  expedition  for  the  second 
voyage  to  polar  regions,  interest 
on  the  part  of  our  readers  is  being  di- 
rected toward  the  shorter  waves  and  in 
response  to  many  requests  for  a  simple 
circuit  for  the  short  waves,  we  are  show- 
ing in  Fig.  1  such  a  means. 

Although  it  is  the  intention  of  the 
expedition  to  communicate  with  voice, 
those  who  rely  upon  telegraphic  signals 
will  probably  be  more  fortunate  in  the 
end,  and  the  receiver  in  question  which 
is  a  detector  and  one  stage  is  worked 
out  on  the  idea  of  a  telegraph  rather  than 
a  broadcast  receiver.  However,  it  may 
also  be  used  for  speech  if  distortion  of 
the  audio  transformer  is  not  to  be  con- 
sidered as  a  deterring  factor. 

The  circuit  is  the  familiar  old  Weagant 
circuit,  about  which  you  have  undoubt- 
edly heard  considerable,  although  per- 
haps under  another  name.  For  the  pur- 
pose intended,  it  is  made  capacitatively 
coupled  to  the  antenna  through  CI  which 
consists  of  two  sheets  of  brass  or  copper 
about  half  inch  by  half  inch  square  with 
an  air  or  mica  dielectric  of  about  one- 
eighth  of  an  inch. 

The  secondary  circuit  is  tuned  by  a 
.00012  mfd.  low  loss  condenser,  while 
the  plate  circuit  is  tuned  by  means  of 
C3  which  is  a  .00025  variable  condenser, 
also  of  the  low  loss  type.  C2  referred 
to  previously  will  probably  be  some- 
what the  order  of  a  five  plate  condenser. 
The  audio  transformer  is  preferably  a 
high  ratio  one  peaking  around  a  thousand 
cycles,  with  plenty  of  distortion  and  no 
biasing  arrangement,  so  maximum  signal 
strength    will   result. 

The  inductances  should  be  wound  a 
la  Lorenz.  The  circle  may  be  3J4  inches 
with  11  dowel  pins.  For  the  range  from 
15  to  25  meters,  LI  should  be  three  turns 
on  the  form  mentioned,  and  from  2  to  3 
turns  on  L2.  The  wire  is  No.  18  paraf- 
fined  annunciator. 

For  the  25  to  45  meter  range  6  turns 
on  LI  and  4  turns  on  L2. 

For  the  35  to  75  meter  band  10  turns 
on  LI  and  4  on  L2. 

From  60  to  115  meter  band  about  20 
turns  on  LI  and  4  to  5  turns  on  L2. 

The  inductance  L2  should  be  arranged 
at  the  filament  end  of  LI  and  after  ex- 
perimentation can  be  permanently  fixed, 
all  the  regeneration  and  oscillation  being 
accomplished  with  the  variable  C3, 
while  the  capacity  C2  takes  care  of 
wavelength   changes. 


CONTRIBUTORS 
Name  Address  City 

Paul  M.  Hayes 918  Bell  St ...Pasadena,  Calif. 

L.  V.  Davenport 383  West  14th  St ...San  Pedro,  Calif. 

Harold  W.  Chandler 520  Wayward  Bldg Victoria,  B.  C. 

R.  A.  Ganatt 17  Lome  Rd.,  Stroud  Green,  N.  4,  England. 

DIAL    TWISTERS 

James  R.  Hartshorne .....2258  Bedford  Ave Brooklyn,  N.  Y. 

J.  Robert  Chandler Arcade  Box  1004 ..Los  Angeles,  Calif. 

B.  Odell 270  Ogden  St Orange,  N.  J. 

G.  L.  Overton Station  G..._ Memphis,  Tenn. 

Mrs.  O.  E.  Titus 285  School  St Berlin,  N.  H. 

J.  H.  Kirkpatrick 6250  Berri  St Montreal,  Que.,  Can 

Russell  J.  Schembs 509  7th  Ave Peoria,  111. 

Luther  Raine Blythe,  Calif. 

Douglas  Black.. Penetanguishene,  Ont.,  Can. 

W.  E.  Millard 811  Kains  Ave Albany,  Calif. 

Frederick  Greger 409  South  River  St Sheboygan,  Wis. 

Frederick  H.  Pollard ...85  Hawthorne  St Brooklyn,  N.  Y. 

Frederic  H.  Perau 210  East  7th  St Oswego,  N.  Y. 

Karl  Hayden Osborne  Harbor,  Skel  Co.. Nova  Scotia,  Can. 

J.  Kinsella... ...57  Crowland  Ave Welland,  Ont.,  Can. 

James  Licitris 644  Baird  St ....Akron,  Ohio. 

D.  Thompson. Galilee,  Sask.,  Can. 

George  Clark 1822  N.  47th  St Seattle,  Wash. 

F.  R.  Fravel ..Bollston,  Va. 

Anthony  D.  Cesare 435  Monroe  St Phoenix,  Ariz. 

Fred  Kesemeyer Bay  City,  Mich. 


The  grid  leak  should  be  anywhere  from 
6  to  8  megohms,  and  several  should  be 
used  to  make  sure  of  getting  a  good  one. 
The  capacity  of  C4  is  around  .00025  or 
.00012  mfd.  Also  make  sure  you  have 
a  good  grid  condenser.  Don't  use  a 
cheap  one.  The  tube  should  slide  into 
oscillation  with  a  faint  hiss  instead  of  a 
plop.  Change  voltages  on  the  detector 
B  and  change  leaks  until  you  arrive  at 
this  condition. 

It  may  be  of  advantage  to  insert  a 
choke  coil  in  series  with  the  plate  at  the 
point  marked  X  in  the  diagram  to  help 
make  the  set  oscillate  easier.  Try  an  air 
core  choke  of  about  100  turns  of  No.  30 
wound  on  an  inch  mailing  tube.  Place 
this  tube  so  it  does  not  have  any  induc- 
tive effect  on  the  other  inductances. 

Use  a  UV200  for  a  detector  and  a 
201-A  for  an  amplifier.  A  thirty  to  forty 
foot  antenna  will  do.  Be  sure  to  get  a 
good  ground,  preferably  a  water  pipe  or 
else  a  long  copper  rod  driven  into  the 
ground.  Gas,  steam,  and  radiator  pipes 
are  not  so  good,  but  better  than  nothing. 
A  single  wire  counterpoise  might  help 
too. 

Let  use  know  some  of  your  results. 
Ninety-nine  per  cent  of  your  results  will 
probably  be  code  stuff,  although  there  is 
a  possibility  that  the  expedition  will  be 
able  to  shove  the  human  voice  back 
across  the  frozen  expanses  to  civilization. 


Riding  the  Pacific  on  the  KDIV,  known 
as  the  SS  Olympic,  L.  V.  Davenport, 
radio  operator,  at  383  West  14th  St., 
San  Pedro,  Calif.,  hearkened  to  our  call 
for  dope  from  experimenters  and  sends 
in  his  pet  circuit,  a  variant  of  the  Wea- 
gant, which  he  describes  as  follows: 

"It  does  not  howl.  I  have  not  been 
able  to  beat  note  on  any  station  with  it 
but  seem  to  have  plenty  of  regeneration. 
In  tuning  the  regenerator  capacity, 
C3,  is  set  at  zero  and  then  increased  to 
bring  up  signal  strength.  With  the 
values  used  there  seems  to  be  a  point 
where  they  start  to  fall  off  again  and 
that  point  is  well  under  the  point  of  free 
oscillation.  This  point  of  reception  also 
varies  with  different  stations  and  wave- 
lengths. 

"The  coils  were  wound  low  loss  fashion 
(Lorenz  probably)  on  a  four-inch  form. 
All  coils  were  made  of  No.  18  DCC  and 
wound  in  the  same  direction,  but  coil 
LI  is  connected  reverse  to  the  others. 
The  condensers  were  just  common  good 
condensers  without  any  verniers.  Coil 
LI  20  turns;  L2  45  turns;  L3  10  turns 
and  L4  45  turns.  Condensers:  CI  and 
C2  .0005  mfd  variable;  C3  .00025  mfd 
variable,  C4  .00025  fixed;  C5  .005  fixed 
bypass;  grid  condenser  .00025  fixed.  C6 
is  a  neutralizing  condenser  which  has  not 
been  necessary. 

"The   set   was  put   together   with   the 


44  RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


Back  again,  with  the  old  reliable  Weagant  circuit,  this  lime  adapted  for  very  short  waves.        The  amplifier  is  arranged  for  maximum  dis- 
tortion so  as  to  get   strongest  telegraph  signals.        Will  do  for  voice   if  not  too   much  attention  is  paid  to  quality.        The  inductances  are 

wound  a  la  Lorenz. 


idea  of  controlled  regeneration  in  both 
the  radio  frequency  and  detector  tubes 
and  no  neutralizing.  I  have  found  that 
a  good  regenerator  in  the  hands  of  an 
experienced  operator  would  get  about  all 
there  is  to  be  found.  Some  of  the  so- 
alcled  neutrodynes  were  not  in  the 
running  at  all.  If  any  other  fans  try 
my  circuit  I  would  like  to  know  how 
they  make  out.  la  m  well  satisfied 
with  it." 


Many  of  our  readers  have  inquired  as 
to  the  possibilities  of  the  inside  antenna. 
This  brings  back  the  age-old  axiom  that 
there  is  nothing  as  good  as  a  good  an- 
tenna. But  if  you  cannot  get  a  good 
antenna,  there  are  several  possibilities 
left  for  you.  The  attic  of  your  house 
would  make  an  ideal  spot  for  an  indoor 
antenna  providing  you  have  a  fair  length 
in  which  the  wires  can  be  strung.  If  you 
have  a  poor  ground  connection,  you  can 
experiment  with  a  counterpoise.  In  the 
apartment  buildings  where  an  attic  is  not 
available  you  will  find  a  picture  mould- 
ing which  can  be  used  to  anchor  an  inside 
aerial. 

While  it  is  true  that  your  signal 
strength  is  lessened  under  interior  con- 
ditions, nevertheless  the  strength  of  dis- 
turbing influences  is  generally  less,  too, 
and  you  may  make  up  for  lower  signal 
strength  in  increased  audio  amplification, 
or  if  you  desire,  radio  frequency  ampli- 
fication. 

Gas  jets,  radiator  pipes  and  other  metal 
lines  in  your  house  are  seldom  as  good  as 
a  water  pipe  which  runs  down  into  the 
ground  and  makes  contact  with  the  main. 
Of  course,  there  is  the  loop  but,  as  a  rule 


it  is  associated  with  super-hets,  and  thus 
it  does  not  always  become  a  playmate  of 
the  one,  two,  and  three  tube  owner. 
The  advantages  of  the  loop  lie  in  its 
directional  properties,  which  often  help 
considerable  in  eliminating  an  undesir- 
able station.  Even  tin  roofs  have  been 
used  for  aerials  and  with  some  success 
where  there  is  a  considerable  area  of  tin 
that  is  not  imperfectly  grounded.  An 
inside  aerial  under  a  tin  roof  is  not  so 
good. 

In  selecting  antenna  wire,  whether  for 
inside  or  outside,  a  type  should  be  se- 
lected which  will  not  oxidize  under  cli- 
matic and  smoke  conditions.  Enamel 
covered  wire  is  good  for  this  purpose  if 
there  is  not  to  be  too  much  strain  im- 
posed on  the  wires. 


Writing  from  2258  Bedford  Ave., 
Brooklyn,  N.  Y.,  James  R.  Hartshorne 
sends  in  a  list  of  summer  reception  sta- 
tions, forty  in  all,  which  testifies  rather 
eloquently  to  his  disregard  of  static  in 
the  good  old  summer  time. 


Just  as  we  were  wondering  whether  the 
feminine  readers  of  this  section  would 
ever  equal  in  numbers  those  of  the  oppo- 
site sex,  we  found  a  letter  from  Mrs.  O. 
E.  Titus,  285  School  St.,  Berlin,  N.  H., 
who  relates  her  experiences  with  a  set 
with  which  she  has  logged  sixty  stations. 
Here  is  her  letter  in  full,  printed  to  show 
other  feminine  readers  of  this  magazine 
that  there  are  some  who  are  really  inter- 
ested in  the  game: 

"Am  wondering  if  the  men  are  the 
only  ones  that  have  a  part  in  the  Pickups 
and    Hookups    department    of    RADIO 


AGE.  About  November  15  last  year  I 
began  turning  the  dials  on  a  Radiola 
III-A,  the  first  receiver  I  ever  used. 
Since  that  date  I  have  been  a  constant 
reader  of  RADIO  AGE  and  think  as 
Mr.  McLaughlin— 

"  'I  have  no  five  tube  neutrodyne, 
Nor  an  eight  tube  super-het;  But  RADIO 
AGE,  from  page  to  page,  Is  the  best 
that  I've  seen  yet.' 

"Am  sending  a  list  of  stations  I  have 
logged  since  last  November.  If  it  is  of 
sufficient  length  to  earn  a  Dial  Twister's 
button,  shall  give  the  credit  to  your 
magazine." 

It  is  not  the  length  of  the  list  which 
aspirants  send  in  covering  their  labors 
that  determines  the  award  of  the  DT 
button.  Rather,  it  is  the  DX  work  from 
the  place  in  which  the  writer  is  located, 
and  the  variety  of  stations  logged.  For 
example,  a  radio  fan  in  Chicago  could 
get  up  a  pretty  good  list  of  stations 
using  the  Chicago  stations  alone,  since 
there  must  be  nearly  two  dozen  of  them. 
But  such  a  list  would  hardly  win  a  but- 
ton. On  the  other  hand,  if  the  same 
individual  were  to  send  in  a  list  showing 
one  of  the  furtherest  Canadians,  a  Mexi- 
can, a  Cuban,  couple  of  Californians,  and 
the  East  Coast,  he  would  stand  a  much 
better  chance  of  getting  the  button.  So  it's 
not  the  length  of  the  list,  but  rather  the 
amount  of  energy  and  initiative  in  going 
after  the  elusive  ones.  We  hope  there 
are  more  letters  from  readers  like  Mrs. 
Titus. 


According  to  advices  from  the  Depart- 
ment of  Commerce,  a  Mr.  Midali,  of 
Italy,   who  has  been   working  on  trans- 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


45 


Send  for  your  free  copy 


Ward's  New  Radio  Catalogue 


The  best  radio  experts  made  this  catalogue. 
It  is  one  of  the  very  best  and  most  com- 
plete books  on  Radio  ever  published. 

Its  52  fully  illustrated  pages  are  simply 
invaluable  to  everyone  interested  in  radio. 
And  one  copy  is  to  be  yours  Free— merely 
for  the  asking! 

It  shows  guaranteed  Radio  sets,  one 
tube  sets  that  give  remarkable  results,  and 
sets  of  every  variety  up  to  Ward's  new 
five-tube  one-dial  control.  Think  of  tun- 
ing in  one  station  after  another  by  turning 
a  single  dial! 

It  shows  guaranteed,  tested  parts,  bat- 


teries, cabinets,  contains  a  list  of  stations, 
a  radio  log  for  recording  stations.  It  is  a 
complete  radio  manual — sent  entirely  free! 

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for  Radio 

And  best  of  all,  the  catalogue  offers  you 
everything  new  in  Radio  at  a  big  saving 
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dise under  a  Golden  Rule  Policy.  You  can  rely 
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46 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


mission  of  electrical  energy  for  power 
purposes  for  the  last  five  years,  has 
developed  his  findings  to  such  a  point 
that  the  experiments  are  a  laboratory 
success  and  only  await  commercial  adap- 
tation. 


An  article  in  "La  Stampa,"  an  Italian 
journal  which  has  been  translated  by 
the  Department  of  Commerce  says: — 

"The  result  obtained  is  that  of  trans- 
mitting electric  energy  in  the  form  of 
alternating    current     without    excessive 


L.  V.  Davenport,  radio  operator  on  the  KDIV,  SS  Olympic,  on  the  Pacific,  sends  in  his 
contribution  for  the  benefit  of  RADIO  AGE  fans.  It  is  a  variant  of  the  Weagant  and  is 
arranged  so  no  neutralizing  capacity  is  required,  although  one  is  shown  in  the  drawing. 
The  coils  are  wound  Lorenz  fashion  on  a  4-inch  form  and  wound  with  No.  18  DDC  wire. 
Regeneration  is  controlled  by  means  of  capacity  C  3  which  is  a  .00025  variable  condenser. 
With  this  set  the  tendency  to  oscillate  is  held  in  subjection  and  with  the  values  given,  Mr. 
Davenport  gets  excellent  results  on  all  waves  within  the  broadcasitng  band. 


losses,  but  in  reality  the  electric  energy 
is  not  transmitted  as  such.  Instead,  the 
system  transforms  the  electric  energy 
into  very  short  electro-magnetic  waves 
of  about  one-millionth  of  a  centimeter. 
These  waves  must  be  about  the  size  of 
light  waves  and  have  nothing  in  com- 
mon with  the  Hertzian  waves  used  in 
radio  communication. 

"These  extremely  short  waves,  liter- 
ally called  vibrations  of  the  electrons, 
constitute  the  means  by  which  the  elec- 
tric energy  is  transmitted  to  a  distant 
receiving  set  which  in  turn  transforms 
them  into  electric  current  of  identical 
characteristics  of  that  used  in  the  trans- 
mitter." 

The  report  further  states  it  is  noted  in 
the  experiments  no  difference  of  poten- 
tial exists  between  the  antenna  and  the 
ground  despite  the  utmost  efforts  to  de- 
tect such  potential  by  means  or  electro- 
dynamic,  electro-magnetic  or  electro- 
static devices  of  a  sensitive  nature.  It 
is  also  claimed  by  this  means  polyphase 
currents  may  be  transmitted. 

Further  reports  are  awaited  with  con- 
siderable interest  in  the  United  States, 
where  the  power  transmission  scheme  of 
Tesla,  years  ago,  excited  wide  interest 
from  its  novelty.  So  far  all  schemes 
have  depended  upon  resonance  of  the 
transmitter  and  the  receiver,  whereas  in 
the  Italian  report  it  is  stated  the  system 
does  not  depend  upon  resonance  between 
two  circuits  as  the  word  resonance  is 
understood  in  radio  circles. 


Anthony  D.  Cesare,  435  East  Monroe 
St.,  Phoenix,  Ariz.,  sends  in  a  list  of 
stations  received  on  a  two  tube  reflex, 
more  or  less  destroying  the  fallacy  that 
desert  countries  are  not  good  for  radio 
communication. 


Harold  W.  Chandler,  secretary  of  the 
Victoria  Radio  Club  at  Victoria,  B.  C, 
sends  us  a  copy  of  a  letter  from  the  club 
in  which  it  goes  on  record  as  favoring 
the  abolition  of  all  radiating  receivers. 
The  letter  is  in  the  form  of  a  memorial 
to  the  Dominion  government  of  Canada, 
and  reads  as  follows: — 

"Whereas  in  the  opinion  of  the  mem- 
bers of  the  Victoria  Radio  Club  the  use 
of  radiating  sets  had  become  a  public 
nuisance,  it  is  the  opinion  of  this  Club 
that  government  action  should  be  taken. 

"We  believe  the  manufacture  and  sale 
of  radiating  sets  in  Canada  should  at 
once  be  stopped  by  law,  that  on  all 
licenses  the  type  of  receiving  sets  should 
be  specified  and  in  a  reasonable  time  the 
use  of  radiating  sets  absolutely  prohib- 
ited by  law.  Also  that  all  radio  inspec- 
tors be  given  full  power  to  act  at  once 
in  cases  of  persistent  interference." 
i  From  the  above  it  is  not  hard  to  see 
the  effect  which  the  "blooper"  has  had 
on  our  Canadian  friends. 


Being  desirous  of  out-logging  one  of 
his  friends  who  possessed  a  factory  built 
set,  George  Clark,  1822  North  47th  St., 
Seattle,  Wash.,  proceeded  to  make  the 
two  tube  ultra-audion  described  in  the 
March  RADIO  AGE  with  which  he 
brought  in  all  manner  of  stations  which 
his  friend  could  not  do.     The  list  is  an 


a 


There  are  many  improvements 
in  the  new  Prest-O-Lite  Battery 


In  this  new  battery  you'll  find  all  the  good  points  and 
high  quality  that  have  made  Prest'O-Lite  an  unfailing 
aid  to  better  radio.  And  in  addition  there  are  many  im- 
portant refinements  and  improvements  that  make  it  the 
most  attractive,  most  convenient  battery  you  can  buy. 

This  new  battery  has  a  beautiful  stippled  finish  hard 
rubber  case  that  blends  with  any  furnishings.  The  case 
L  Jiolded  in  one  piece,  giving  sturdy,  leak-proof  strength. 

To  make  the  battery  convenient  to  carry,  the  handle 
has  been  given  a  comfortable  rubber  grip. 

The  oversize  terminal  nuts  on  the  binding  posts  are 
easy  to  turn  and  insure  perfect  contacts. 

Novel  rubber  insulators  completely  cover  the  tops 
and  sides  of  the  cell  connectors,  preserving  the  original 


fine  finished  appearance  at  all  times  and  giving  protection 
against  accidental  short  circuits. 

No  effort  has  been  spared  to  make  this  a  battery  you 
will  be  proud  to  own.  Yet,  like  the  rest  of  the  Prest- 
O-Lite  line,  it  is  priced  to  offer  you  the  biggest  value  of 
the  day.  Ask  your  dealer  to  show  you  this  battery  and 
the  Prest-O-Lite  Chart  that  helps  you  select  the  right 
battery  for  your  set.  Or  write  Indianapolis  for  a  copy 
of  our  interesting  handbook  on  radio  storage  batteries 
and  how  to  charge  them. 

T  H  E    P  R  E  S  T  -  O  -L  I  TE   C  O  .  ,    Inc. 

INDIANAPOLIS,  IND. 

New  York  San  Francisco 

In  Canada :  Prest-O-Lite  Company  of  Canada.  Limited.  Toronto,  Ontario 


-4> 


*     Tested  and  Approved  by  RADIO  AGE     * 


48 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


Douglas  Black  of  (go  easy  now,  Mr. 
Printer) — Penetanguishene,  Ontario,  Can- 
ada, sends  in  a  good  list  of  stations 
picked  up  on  a  crystal  detector.  There 
are  14  stations  in  all  and  most  of  them 
represent  distances  in  excess  of  500 
miles. 


(Continued  from  page  46) 
excellent  testimonial  of  the  sturdiness  of 
the  ultra-audion. 


F.  R.  Fravel,  Bollston,  Va.,  compli- 
ments us  upon  the  crystal  description  in 
the  July  issue  and  thinks  that  too  little 
attention  is  paid  to  the  lowly  mineral. 
He  gets  KDKA  and  others  of  the  higher 
powered  class  up  to  a  distance  of  about 
1,100  miles  when  he  is  not  disturbed  by 
the  locals  in  Washington,  D.  C. 


Here's  another  fan  who  finds  that 
RADIO  AGE  sets  work.  He  is  Fred 
Kesemeyer,  proprietor  of  the  O.  K. 
Garage  at  Bay  City,  Michigan.  He 
says: — "I  have  made  a  set  like  yours  on 
page  18,  March  RADIO  AGE,  and  it 
works  fine." 


James  Licitris,  644  Baird  St. ,•  Akron, 
Ohio,  a  13  year  old  fan,  has  been  plug- 
ging away  for  a  button  with  a  single 
tuber.  His  list  seems  to  represent  a 
good  deal  of  midnight  oil  burned  so  we 
are  going  to  forward  him  an  emblem. 


Frederic  H.  Perau,  210  East  Seventh 
St.,  Oswego,  N.  Y.,  is  quite  a  stamp  fan 
besides  being  a  radio  listener,  although 
his  flair  for  stamps  is  of  the  broadcasting 
station  type  instead  of  postage.  He  be- 
lieves the  stamp  collecting  fad  is  the  one 
way  to  make  sure  of  your  reception. 
Incidentally  he  sends  in  a  list  of  stations 
that  would  stagger  the  linotype  operator, 
but  certainly  deserves  the  button. 


D.  Thompson,  Galilee,  Sask.,  Canada, 
has  written  asking  for  a  circuit  by  means 
of  which  the  20,  40,  80,  and  100  meter 
bands  may  be  spanned.  The  circuit  in 
question  is  being  printed  in  this  section, 
being  a  detector  and  one  stage  amplifier, 
suitable  for  telegraphic  and  phone  recep- 
tion on  these  lower  wavelengths. 


Using  a  two  tube  set  Frederic  H.  Pol- 
lard, 85  Hawthorne  St.,  Brooklyn,  N.  Y., 
gets  'em  from  the  Atlantic  to  the  Pacific 
and  insures  his  getting  one  of  the  DT 
buttons. 


J.  Kinsella,  57  Crowland  Ave.,  Wel- 
land,  Ont.,  Canada,  using  a  Flewelling 
super,  reports  great  success  with  his  new 
set.  He  is  an  ardent  RADIO  AGE  fan 
and  opines  that  if  the  magazine  were 
selling  for  a  dollar  a  copy  he  would  get 
his  just  the  same. 


Further  ahead  in  this  column  we 
seemed  to  be  having  a  run  on  Canadians. 
Now  we  seem  to  be  doing  the  same  thing 
on  Frederics,  for  this  is  the  third  gentle- 
man by  that  first  name  who  has  written 
this  department.  This  one  is  Frederic 
Greger,  409  South  River  St.,  Sheboygan, 
Wis.,  who  related  his  experiences  with  a 
two  tube  ultra-audion  with  which  he  is 
having  great  success. 


Karl  Hayden,  Osborne  Harbor,  Skel 
Co.,  Nova  Scotia,  Canada,  using  a  one 
tube  set,  furnishes  us  with  a  good  list  of 
stations  heard,  going  so  far  as  to  pick 
up  PWX  from  way  up  north. 


Using  a  Weagant  circuit  one  tuber, 
Luther  Raine,  at  Blythe,  Calif.,  tells  us 
that  it  brings  in  the  stations  fine  with 
ease  of  control.  He  also  reports  hearing 
two  Italian  stations. 


Russell  J.  Schembs,  509  7th  Ave., 
Peoria,  111.,  built  over  a  factory  set  into 
a  non-radiating  type  and  with  it  has 
listened  to  65  stations  in  five  hours.  In 
all  he  heard  193  stations  in  seven  coun- 
tries and  48  amateurs  in  the  United 
States  and  Canada.  A  ship  in  distress 
off  the  coast  of  Ireland  is  also  advanced 
as  a  reason  for  the  award  of  the  DT 
button. 


J.  H.  Kirkpatrick,  6250  Berrie  St., 
Montreal,  Que.,  Canada,  using  an  ultra- 
audion,  sends  in  such  a  formidable  array 
of  stations  that  he  is  automatically 
awarded  the  button.  The  set  is  the  one 
described  by  Brainard  Foote  in  the 
September  RADIO   AGE. 


A  bulletin  "Joining  the  Electric  Wave 
and  Heat  Wave  Spectra"  by  E.  F. 
Nichols  and  J.  D.  Tear,  has  just  been 
issued  from  the  Smithsonian  Report  for 
1923,  and  is  available  from  the  Govern, 
ment  Printing  Office  at  Washington- 
D.  C. 


W.  E.  Millard,  811  Kains  Ave.,  Al- 
bany, Calif.,  using  one  stage  of  radio 
frequency  ahead  of  a  detector,  reports 
fine  results.  The  layout  is  a  semi-toroid 
coil  and  a  three  circuit  tuner,  all  built 
along  low  loss  lines. 


Roscoe  Bundy  seems  to  have  stirred  up  at  least 
one  hornet's  nest  on  the  subject  of  resistance  coupled 
amplification,  according  to  the  way  we  dope  out  a 
letter  received  from  J.  E.  Roberts,  engineer,  residing 
at  14724  Detroit  Ave.,  Lakewood.'Ohio. 

Mr.  Roberts  takes  exception  to  Roscoe's  statement 
that  resistance  coupled  amplification,  stage  for 
stage,  does  not  equal  transformer  coupling. 

Feeling  that  our  readers  are  interested  in  anything 
bearing  on  this  subject  we  are  printing  Mr.  Roberts' 
letter  in  full: 

Good  Dope 

"I  have  just  finished  reading  the  July  issue  of 
RADIO  AGE.  from  cover  to  cover,  and  was  par- 
ticularly interested  in  the  able  article  on  the  coming 
set — the  initial  article  by  Mr.  Roscoe  Bundy — 
which  was  fine,  until  it  was  spoiled  by  a  wild  mis- 
statement which  took  all  the  good  out  of  the  balance 
of  the  article. 

"Mr.  Bundy  was  good  till  he  got  to  the  paragraph 
on  page  10.  headed  'Resistance  coupling'  and  there 
he  went  all  to  pieces  when  he  stated  that  three  stages 
of  resistance  were  necessary  to  equal  two  stages  of 
transformer  coupling  in  'degree  of  amplification.' 
If  by  'degree'  he  means  volume  only,  he  is  wrong 
decidedly — and  if  in  that  term  'degree'  he  includes 
clarity  of  reproduction  and  faithfulness  of  repro- 
duction he  is  wrong  again  and  then  some. 

"I  imagine  that  Mr.  Bundy  has  never  made  any 
direct  comparison  of  resistance  coupling  with  trans- 
former coupling  under  parallel  conditions  or,  if  he 
has,  the  comparison  was  made  some  time  ago,  when 
his  statement  might,  and  probably  would  have  been 
true — but  methods  change  rapidly  in  radio  as  you 
know. 

"If  that  is  not  the  case,  then  he  must  have  been 
repeating,  without  personal  knowledge,  otatements 
that  have  been  in  print  repeatedly,  to  the  same 
effect,  and  which  are  equally  in  error,  or.  to  put  it 
more  smoothly,  equally  behind  the  times. 

Are  Equal 

"The  facts  are.  today,  that  a  resistance  coupled 
set,  of  a  quality  of  material  and  workmanship  equal 
to  a  transformer  coupled  set,  will  give  fully  equal 
volume,  stage  for  stage,  of  any  transformer  coupled 
combination — in  other  words,  a  stage  of  resistance 
(Turn  to  page  50) 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


49 


New  Crosley  Radio  Ideas  for  1926 


Radio  with  all  its  romance  knows 
no  more  magic  name  than  Crosley. 
With  the  improvements  Powel 
Crosley,  Jr.,  presents  in  his  line 
for  1926  he  makes  his  greatest 
stride  forward  in  the  development 
of  radio  for  the  millions. 

Again  he  demonstrates  the  value 
producing  economies  of  gigantic 
production.  Again  he  demonstrates 
that  all  you  can  expect  from  radio 
can  be  secured  through  Crosley 
apparatus. 


Add  10%  To  All 

Prices  West 

of  Rocky  Mountains 


The  Crosley  "Pup" 

A  genuine  Armstrong 
regenerative  double  cir- 
cuit receiver  for  $9.75.  A 
refinement  of  the  one  tube 
set  with  which  Leonard 
Weeks,  of  Minot,  N.  D., 
heard  the  MacMillan 
polar  expedition  while  the 
rest  of  the  world  listened 
in  vain.  One  dry  battery, 
one  B  battery,  tube, 
phones,  and  antenna  only 
accessories  needed. 
Price  without  ac-  $Q.75 
cessories,  J 


Super-Trirdyn 
Special  with 
matched  console 
table  and  Musi- 
cone  De  Luxe, 
$112.50.  Table 
separate,   $25.00. 


The  New  1926 

SUPER-TRIRDYNS 


DURING  the  past  three  years  Crosley  engineers  have 
developed  a  wonder  circuit — the  Super-Trirdyn.  This 
combines  tuned  radio  frequency  amplification,  regeneration, 
reflex  audio  amplification,  making  three  tubes  do  the  work  of 
five.  There  is  saving  both  in  first  cost  and  upkeep.  Bat- 
teries last  longer.     There  are  less  tubes  to  replace. 

Competitive  tests  reveal  that  no  present  day  set,  regard- 
less of  price,  is  capable  of  out-performing  these  1926  improved 
Super-Trirdyns.  They  give  all  the  volume  possible  with  the 
best  of  existing  vacuum  tubes. 

By  its  superlative  performance,  the  original  Trirdyn  model 
quickly  built  up  a  world-wide  reputation.  Yet  these  newest 
models  incorporate  vital  improvements  which  are  immedi- 
ately apparent  in  the  vitally  finer  results  they  give. 

Coupled  with  their  improved  performance,  the  Trirdyn 
presents  a  new  appearance  that  recognizes  no  peer  in  the 
quality  radio  field. 


The  Musicones 

The  first  loud  speaker  to  repro- 
duce the  full  tonal  range  of  voice 
or  instrument  without  distortion. 
Superior  to  all  others  regardless 
of  cost.  Investigation  will  prove 
this.  Rapidly  replacing  other 
types  of  speakers.  500,000  in  use 
by  January  1st.  Crosley  devel- 
oped unit  secret  of  its  remarkable 
success.  De  Luxe  Model,  ma- 
hogany cabinet,  $1  'T-50 
$27.50,  Regular,  1/ 


The  Super-Trirdyn  Regular 

Crosley  Trirdyns  have  been  the 
marvel  of  the  radio  world.  No 
radiation.  This  model  is  a  simple, 
richly  finished  cabinet  of  solid  ma- 
hogany. Same  performance  as 
the  "Special"  at  $60.  $C(\ 
Price  is  without  accessories,     Ov 


Crosley  manufactures  receiving  sets  which  are  licensed 
under  Armstrong  U  S.  Patent  No.  1,1 13.149  and  prices 
from  $9.75  to  560.00  withous  accessories. 

BETTER— COSTS  LESS 

RADIO 


The  Super-Trirdyn  Special 

The  famous  Crosley  Trirdyn  greatly  improved. 
New  Crosley  designed  low  loss  Vernier  Condens- 
er— new  worm  rotary  type  tickler  control.  Wiring 
concealed  under  subpanel.  In  this  model  all  dry 
batteries  are  contained  in  the  cabinet.  $£A 
Price  quoted  is  without  accessories \J\J 


New  2-tube  51 
Improved  popular  Cros- 
ley 2-tube  No.  51,  Special 
De  Luxe.  Double  circuit; 
New  Crosley  Vernier  con- 
densers; worm  type  tick- 
ler; cabinet  will  hold  all 
dry  batteries.  Price  with- 
out accessories   $/}'5.50 


New  3-tube  52 

Another  popular 
Crosley  model  —  the 
3-tube  52  Special  De 
Luxe.  Redesigned 
with  new  Crosley  Ver- 
nier condensers,  rotary 
type  tickler  and  beau- 
ti  fully  finished  cabinet. 

without   ^  ^ 
accessories 


The    Crosley    Radio    Corporation — Cincinnati 

Crosley  Owns  and  Operates  Super  Power  Station  WLW,  Cincinnati 
*     Tested  and  Approved  by  RADIO  AGE     * 


50 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


Stand  By! 

FUN 

J£      FOR 

FANS 

Announcing! 

STATION 

L-A-F-F 


will  broadcast  ZIFFS  Fun 
Revue,  the  15th  of  each  month 
and  invites  radio  fans  to  TUNE 
IN  on  this  program. 

This  entertainment  is  pur- 
veyed by  FAMOUS  FUN- 
MAKERS  and,  if  you  act 
promptly,  you  won't  miss  the 
current  issue  of  ZIFFS  Maga- 
zine. 

Just  clip  the  coupon  now! — it 
buys  a  round  trip  ticket  to 
Funville,  far  from  the  bore- 
dom of  sweltering  summer; 
you'll  be  tuning  in  on  the 
longest  wave  length  of  breezy 
humor  in  the  U.  S.  A. 

ZIFFS  keeps  you  chuckling 
from  one  issue  till  the  next. 
You  welcome  its  coming  like  a 
shipwrecked  sailor  greets  the 
sight  of  a  homeward  bound 
liner,  flying  the  Stars  and 
Stripes.    SOME  WELCOME! 

ZIFFS  Entertainment  for 
Everybody  never  wears  out 
its  welcome.  Station  L-A-F-F 
never  SIGNS  OFF! 

Gentlemen: 

Enclosed  find  25c.  I  want  to  tune 
in  on  ZIFFS  Sept.  Program. 

Name 


Address .. 


State. 


Pickups  and  Hookups 


(Continued  from  page  48) 


The  above  figure  5  shows  the  diagram  of  a  5  waiter  sent  in  by  Paul  M.  Hayes. 
It  is  loose  coupled  to  the  antenna  and  counterpoise  for  the  reason  that  all 
amateurs  should  by  now  use  this  type  of  coupling  to  do  away  with  harmonics, 
key  clicks  and  other  interferences  more  or  less  attributed  to  the  conductive 
coupled  set.  C3  is  a  .0005  variable  in  the  counterpoise  lead  while  A  is  the 
r.  f.  ammeter.  CI  is  .002  mfd.  and  Rl  is  10,000  ohms.  C2  is  the  glass  pack 
condenser  described  by  Hayes  in  this  section.  The  spark  coil  is  operated 
off  the  same  battery  as  the  tube.  The  MA  (milliammeter)  and  V  (voltmeter) 
are  not  absolutely  essential,  but  they  come  in  handy.  If  you  have  any  trouble 
with  the  set,  look  up  some  transmitting  amateur  in  your  neighborhood. 
Doubtless  he  will  be  interested  in  the  conversion  of  aBCL  into  a  brass  pounder. 


coupling,  today,  is  the  equal  of  any  stage  of  trans- 
former coupling.  This  is  in  volume  only — in  perfection 
of  reproduction  and  the  absence  of  distortion,  there 
is  no  comparison  possible,  for  the  resistance  coupling 
does  not  distort. 

"Further — the  suggestion  that  three  stages  of 
resistance  MUST  be  used  to  replace  two  stages  of 
transformer  coupling  is  also  misleading.  In  three 
separate  instances,  occurring  within  the  past  month, 
an  attempt  has  been  made  to  replace  two  regular 
stages  of  transformer  amplification,  with  a  well 
known  3-tube  resistance  unit,  with  the  uniform  result 
that  the  third  stage  of  resistance  was  not  practical, 
except  for  auditorium  reproduction,  the  resultant 
volume  being  too  great  for  comfortable  reception 
in  the  home.  In  one  case  an  extra  output  was 
arranged  for  after  the  second  AF  stage  for  regular 
use — in  the  two  other  cases,  the  last  or  third  stage 
was  removed,  leaving  two  stages  of  resistance  coupling 
— the  same  number  of  stages  as  the  transformer 
coupling  which  had  been  removed,  with  an  increase 
in  volume  and  absolute  absence  of  distortion. 

"In  addition,  it  has  been  found  that  there  are  few 
loudspeakers  of  any  quality,  which  can  hold  the 
full  output  of  three  stages  of  resistance  amplification, 
without  'blasting*  or  excessive  diaphragm  vibration. 

"Again,  a  properly  built  resistance  coupled  set 
does  not  need  more  than  90  volts  of  'B'  battery  for 
ordinary  reception — the  addition  of  another  45 
volt  block  does  not  help  matters  materially,  and 
often  interferes  with  the  quality  of  the  output. 

"Still  again,  the  matter  of  voltage  is  not  important, 
for  the  draft  on  a  'B'  battery,  of  a  resistance  coupled 
set  is  vastly  less  than  a  similar  set,  transformer 
coupled,  in  'B'  amperage,  and  the  'A'  battery  con- 
sumption is  also  reduced  to  a  minimum.  The  writer 
has  a  4-tube  fully  resistance  coupled  set,  working 
on  4  201-A  tubes,  and  the  readings  of  the  meters 
at  the  best  point  of  operation  show  an  A  battery 
consumption  of  .7  amp.  at  3.9  volts,  B  battery,  90 
volts  and  less  than  7  milliamps  draft  on  the  four 
tubes. 

"The  above  statements  are  not  to  be  considered 
as  other  than  a  criticism  of  a  friendly  and  constructive 
nature.     The  statements  are  open   to  verification, 

*     Tested  and  Approved  by  RADIO  AGE     # 


or  proof,  either  by  tests  in  your  own  laboratory,  or 
I  can  submit  proofs  of  same  in  any  form  that  you 
may  find  proper — the  point  is,  that  I  believe  that 
you  are  endeavoring  to  broadcast  the  most  recent 
facts  in  your  publications,  and  the  remarks  in  para- 
graph on  page  10  referred  to  were  an  oversight,  in 
view  of  present  day  accomplishments,  no  matter 
how  true  they  may  have  been  a  year  ago." 

Mr.  Roberts  did  not  state  in  his  letter  whether 
the  resistance  coupled  outfit  to  which  he  refers  is 
biased  or  not.  If  it  is  not  biased  then  comparison 
against  transformer  coupling  is  out  of  the  question. 
If  it  is  biased  then  the  resistance  coupling  more 
nearly  approaches  the  standard  of  the  transformer 
coupled  set.  It  is  rather  strange  too  that  manu- 
facturers of  resistance  units  do  not  claim  stage  for 
stage  parity  with  transformer  coupling. 

In  this  connection  we  note  that  Rathbun  in  this 
issue  has  a  set  of  blue  prints  and  a  descriptive  article 
on  "audio  amplification"  in  which  he  touches  upon 
resistance  coupling.  His  resistance  stages  are  biased 
for  maximum  clarity.  There  is  no  question  but  that 
resistance  coupling  does  not  distort  of  itself,  but 
unbiased  tubes  will.   Hence  the  bias. 

This  is  a  subject  that  could  be  fought  oVer  for 
years.  Frankly  we  would  like  to  have  our  Pickups 
family  go  into  the  subject  and  let  us  have  their 
opinions.  Some  of  you  will  agree  with  Mr.  Roberts. 
Others  will  disagree.     Let  us  know  your  verdict. 

Paul  M.  Hayes,  918  Bell  St.,  Pasadena,  Calif, 
who  is  quite  anxious  that  some  of  the  receiving  fans 
should  come  into  the  dot  and  dash  game,  sends  in 
a  diagram  of  an  inexpensive  five  wa.tter  making  use 
of  spark  coil  potential  applied  to  the  plate  of  the 
tube.  The  circuit  is  given  elsewhere  in  this  column 
and  the  description  follows: 

"This  is  for  the  beginning  brass  pounder  and  is 
inexpensive.  It  is  a  5  watt  I.  C.  W.  set,  using  a  six 
volt  storage  battery  for  both  the  filament  and  plate 
supply.  The  panel  is  7  by  12;  the  parts:  a  zero  to 
two  and  a  half  ammeter,  one  4  terminal  spark  coil, 
a  glass  plate  condenser,  a  5  watt  tube  (UV202) 
socket,  rheostat,  inductance,  .0005  variable  con- 
denser, 10,000  ohm  grid  leak,  and  a  .002  fixed  con- 
denser. 


AMSCO 

AN NOUNCES    A. 

SPACE -SAVING 

S.L.F.    CONDENSER 


# 


SOlV&Ct  ♦  The  space  problem  of  the 
straight- line  frequency  condenser.  The 
new  AMSCO  Allocating  Condenser  is  in- 
geniously designed  to  save  room  in  the 
cabinet  —  yet  spreads  the  stations  evenly 
around  the  dial,  according  to  frequency. 
Greatly  improves  the  selectivity  of  the  set 
and  simplifies  tuning.  Three  sizes — Single 
or  Siamese. 

Ask  your  dealer — or  write  Dept.  P 

AMSCO  PRODUCTS,  INC. 

Broome  and  Lafayette  Streets,  New  York  City 
MAKERS  OF  MELCO  SUPREME  RADIO  RECEIVERS 


*     Tested  and  Approved 
by  RADIO  AGE     * 


Half  a  Heart  is  the  secret. 
Half  a  Heartisthe  shape 
of   the   rotor   plates. 


Half  a  Heart  is  the  new 
symbol  for  efficient  S.  L.  F. 
variable  condensers. 


52  RADIO  AGE /or  September,  1925 

WITH 


The  Magazine  of  the  Hour 


URERS 


Mohawk    Speeds    Up 
Production 

Steam  has  been  ordered  up  at  the  two 
large  manufactories  of  the  Mohawk  Elec- 
tric Corporation,  makers  of  the  Mohawk 
single  dial  5-tube  radio  receiver,  it  was 
announced  by  Gustave  Frankel,  presi- 
dent. With  the  letting  of  several  large 
contracts  for  raw  materials  and  various 
accessories,  including  20,000  Vesta  Storage 
Batteries,  the  work  of  turning  out  the 
first  quota  of  the  new  model  to  be  re- 
leased soon  is  about  to  get  under  way. 
According  to  Mr.  Frankel,  preparations 
are  nearly  complete. 

At  the  large  plant  in  Chicago,  where 
the  general  offices  of  the  Mohawk  organi- 
zation are  also  located,  the  decks  have 
been  cleared  for  action.  According  to 
Douglas  De  Mare,  general  manager  and 
factory  superintendent,  actual  manu- 
facturing is  expected  to  begin  some  time 
this  month.  The  factory  personnel  has 
already  been  increased,  and  more  men  will 
be  employed  as  the  work  progresses. 

"The  new  Mohawk  will  be  in  every  way 
as  distinctive  as  the  old,"  Mr.  Frankel 
declared  in  discussing  the  latest  model. 

"When  we  came  out  with  our  set  last 
fall  we  entered  a  field  in  which  single  dial 
control  was  looked  upon  with  skepticism 
by  fans  and  many  experts  alike.  As 
pioneers  of  one  dial  control,  it  was  our 
aim  to  demonstrate  to  the  public  the 
efficiency  and  practicability  of  a  5-tube 
tuned  radio  frequency  receiver  operated 
by  only  one  knob.  Figures  now  show 
that  we  have  been  successful  beyond  our 
expectations.  The  resistance  to  single 
control  has  been  greatly  decreased,  and 
it  is  recognized  in  almost  every  quarter 
as  thoroughly  practical.  It  is  evident 
that  the  day  of  single  control  is  at  hand. 
This  is  sustained  by  the  increasing  num- 
ber of  one  dial  sets  coming  on  the  market, 
and  by  the  dozens  of  different  gang-con- 
densers now  being  offered  to  the  fan 
who  desires  to  build  a  one  dial  receiver." 


Thordarson  Announces  the 
"Autoformer" 

The  low  notes  of  the  organ,  base  viol, 
tuba,  English  horn  and  of  other  instru- 
ments below  100  cycles  are  said  to  be 
amplified  as  perfectly  as  high  notes  by 
the  latest  Thordarson  development,  the 
Autoformer  All  Frequency  Amplifier. 
The  Autoformer  is  an  adaption  of  ca- 
pacities, impedances  and  resistances, 
developed  in  the  Thordarson  laborator- 
ies at  Chicago.  It  is  similar  in  principle 
to  the  line  amplifiers  now  in  use  at  the 
more    recently    installed    stations. 

Three  stages  of  Autoformer  amplifica- 
tion are  reported  to  amplify  with  even 
magnitude  and  beautiful  clarity  all  notes 
within  range  of  the  human  ear  and  to 
deliver  more  amplification  than  two 
stages  of  audio  transformers. 

An  Autoformer  hook-up  bulletin  is 
just  off  the  press.  Copies  may  be  had 
by  writing  to  Thordarson  Electric  Mfg. 
Co.,  500   W.   Huron   St.,   Chicago. 


Phenix  Radio  Corporation  Re- 
Incorporates 

Phenix  Radio  Corporation,  114-116 
East  25th  Street,  New  York  City,  an- 
nounces a  re-incorporation  with  an  active 
capital  of  $215,000.00.  W.  A.  Eisen- 
hauer,  formerly  in  charge  of  advertising 
with  Radio  News,  remains  President  of 
the  Corporation;  R.  E.  Lacault,  E.  E., 
formerly  associate  editor  of  Radio  News 
and  Radio  Research  Engineer  with  the 
French  Signal  Corps  Research  Labora- 
tories, is  Vice  President;  Ernest  Will- 
voseder,  formerly  treasurer  of  American 
Chicle  Company,  is  Secretary.  Henri 
Conrad,  famous  musical  director,  is 
among  the  Board  of  Directors. 

This  new  capital  was  secured  for  the 
further  promotion  of  the  Corporation 
next  year  in  the  manufacture  of  its  Ultra- 
Vernier  Tuning  Control,  Ultra-Lowloss 
Condenser  (both  a  straight-line  wave- 
length and  a  straight-line  frequency), 
designed  by  R.  E.  Lacault.  Also  the  pro- 
duction and  distribution  of  a  new  radio 
receiver,  the  Ultradyne  Model  L-3,  a 
6-tube  receiver  with  built-in  loud  speaker 
but  without  panel,  dials  or  knobs.  The 
new  receiver  will  be  very  compact  and 
a  beautiful  instrument  for  the  home. 


Buys  Control  of  Radio 
Company- 
Controlling  stock  in  the  Veri-Chrome 
Laboratories    of    Cincinnati,    Ohio,    has 
been  purchased  by  officers  of  the  Formica 
Insulation   Company. 

The  Veri  -  Chrome  Laboratories  de- 
veloped and  put  on  the  market  last  year 
a  method  of  marking  radio  panels  which 
is  a  big  step  in  advance  over  the  engrav- 
ing methods  previously  used. 

The  company  has  numerous  contracts 
with  leading  radio  set  manufacturers 
all  over  the  country  for  decoration  of 
their  panels.  The  process  permits  the 
use  of  high  grade  Formica  panels,  beauti- 
fully decorated  at  no  greater  cost  than 
for  inferior  materials. 

With  the  financial  and  production 
resources  of  the  Formica  Insulation 
Company  behind  the  company,  a  large 
extension  of  its  business  will  be  possible. 
The  business,  however,  will  remain  under 
the  management  of  the  men  who  origin- 
ated the  process  and  who  have  developed 
the    business. 

The  process  is  one  of  lithography  which 
makes  rapid  decoration  of  panels  pos- 
sible. Tuning  scales  may  be  placed 
directly  on  the  panel — eliminating  the 
use  of  dials  and  making  it  possible  to  use 
pointers — this  making  important  econo- 
mies  possible. 

Several  leading  set  makers  in  Cin- 
cinnati and  Dayton  are  already  using 
the    process. 


Young";  Engineer   Designs 
Jewett  Set 

Not  so  long  ago  public  interest  became 
attracted  to  the  plan  fathered  by  Edward 
H.  Jewett  of  encouraging  youthful  in- 
ventive interest  in  the  radio  world. 
Somehow  or  other  it  became  known 
that  at  the  Jewett  plant  there  was  always 
a  sympathetic  hearing  of  the  young  idea. 

As  always,  in  the  discussion  which 
attaches  to  such  news,  a  good  deal  of 
sentiment  was  mixed  in  with  opinions. 
Mr.  Jewett  protested  that  there  was 
nothing  sentimental  about  it,  nor  philan- 
thropic; that  it  was  simply  practical 
encouragement  to  youth  with  the  cer- 
tainty of  yielding  profitable  discoveries. 

How  right  he  was  is  illustrated  in  the 
case  of  the  new  Jewett  receiving  set, 
which  takes  its  place  among  his  factory's 
products  for  the  forthcoming  radio  season. 
The  engineer  who  did  nearly  all  of  the 
major  development  work  on  the  set — 
an  eighteen  months'  job,  is  Edward  H. 
Clark,  one  of  the  youngsters  who  found 
encouragement  at  the  hands  of  Mr. 
Jewett's  staff.  As  yet  there  has  been  no 
opportunity  for  a  public  verdict  of  the 
set,  but  the  trade  opinion  is  said  to  be 
very  high:  It  is  a  5-tube  tuned  radio 
frequency  set;  two  radio,  detector  and 
two  audio.  It  has  2  controls.  Several 
of  the  features  are  announced  as  new 
and  covered  under  special  patents.  Mr. 
Clark  is  only  one  of  several  engineers 
who  are  producing  new  things  in  radio 
under  the  protective  encouragement  of 
the  Jewett  people. 

Products  from  the  same  source  this 
Autumn  will  also  include  the  familiar 
Superspeaker  in  conventional  and  con- 
sole types;  the  Vemco-Unit,  the  Micro- 
Dial,  the  Parkay  Cabinet  and  the  High- 
boy with  built-in  horn. 


RADIO  AGE  is  an  independent  mag- 
azine. 


"Public  Is  Going  to  Buy  With 
Its  Ears" — Priess 

"Radio  this  coming  season  will  be 
competitive  on  performance.  It  will  be 
an  engineer's  year.  Every  so-called 
selling  point  will  be  subordinated  to 
what  the  set  actually  can  do." 

Such  is  the  statement  of  William  H. 
Priess,  president  of  the  Priess  Radio 
Corporation,  and  a  widely  known  per- 
sonality in  the  technical  ranks  of  radio. 
He  explained  further: 

"The  determining  marks  of  desira- 
bility in  a  radio  receiving  set  have  come 
to  be  volume  and  distance.  These  quali- 
ties have  risen  above  all  others  in  the  list 
of  desirable  attributes  a  receiver  should 
have. 

"The  emphasis  which  has  been  placed 
on  'distance'  has  put  a  great  strain  on 
radio  engineering  talent;  the  required 
development  was  out  of  all  comparison 
with  the  speed  that  has  marked  progress 
in  other  phases  of  the  electrical  industry. 

"Nevertheless,  the  demand  has  been 
met,  as  the  forthcoming  season  will  prove." 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


53 


Bristol   Loud   Speaker   Tester 

THE  Bristol  Loud  Speaker  Testing 
Apparatus,  known  by  trade  name  as 
Comparaphon,  was  designed  to  enable 
the  radio  dealer  to  demonstrate  various 
types  of  horns  for  the  prospective  cus- 
tomer, and  to  demonstrate  under  ap- 
proximately the  same  conditions  as  when 
used  on  a  radio  receiver.  It  is  not  often 
possible  to  demonstrate  horns  on  a 
receiving  set  under  usual  broadcast  con- 
ditions. 

The  apparatus  consists  of  a  specially 
constructed  double  button  microphone, 
arranged  to  be  used  in  conjunction  with 
a  phonograph.  The  microphone  takes 
the  place  of  the  usual  sound  box.  The 
record  groove  actuates  the  electrode 
between  the  buttons  instead  of  the  usual 
arrangement  of  allowing  the  electrode 
to  be  operated  by  a  diaphragm  from 
voice   impulses. 

The  control  box  contains  a  step-up 
•repeater  coil  having  a  split  primary 
winding,  which  is  to  allow  both  sides  of 
the  microphone  to  be  used.  This  primary 
winding  is  so  .designed  that  it  matches 
the  impedance  of  the  microphone  at 
approximately  1000  cycles.  The  second- 
ary of  the  repeater  coil  is  wound  to  have 
an  impedance  approximately  equal  to 
that  of  a  201-A  Tube  operating  100  volts 
which  is  about  2  1-2  Henrys. 

A  three  point  switch  is  placed  on  top 
of  the  test  set  and  so  connected  that  the 
output  from  the  repeater  coil  can  be 
instantly  shifted  to  any  of  three  horns. 
The  test  set  requires  4  to  S,  or  a  6  volt 
storage  battery  for  its  current  supply. 

USL  "Broadcast  Receptor" 
Features  Simplicity 

TTSL  Radio,  Inc.,  Niagara  Falls,  N.  Y., 
^—'  has  just  placed  on  the  market  the  USL 
Broadcast  Receptor,  a  moderately  priced 
5-tube  tuned  radio  frequency  receiver. 
This  set  is  attracting  considerable  atten- 
tion due  to  its  attractiveness,  simplicity, 
selectivity,  range  and  its  unusual  tone 
qualities. 

By  arrangement  with  U.  S.  Light  & 
Heat  Corporation,  manufacturers  of 
USL  storage  batteries,  the  distribution 
and  sale  of  the  USL  Broadcast  Receptor 
is  offered  to  USL  battery  distributors. 

Following  is  a  description  of  the  USL 
Broadcast  Receptor: 

Trade  name — USL  Broadcast  Receptor. 

Model  Number— RC-5. 

Type — One  stage  tuned  radio  frequency 
amplication,  detector  and  three  stages 
resistance — coupled  audio  frequency  am- 
plification. 

Number  of  tubes — Five. 

Type  of  tubes — Hard  amplifying. 

Number  of  controls — Tuning,  two — 
Volume,  one — Antenna,  one. 

Batteries — "A"  storage;  "B"  90  volts 
storage  or  dry. 

Dimensions — 23  3-4  in.  long  x  10  3-8 
in.  deep  x  9  1-2  in.  high. 

Finish — Cabinet — two-tone  American 
Walnut.  Panel — Aluminum     finished 

stump  walnut  and  gold. 

Price — $80.00  less  accessories.  Pacific 
Coast,  S85.00. 


Beg  Your  Pardon 
In  the  comment  on  the  method  of  overcoming 
oscillations  in  receivers  touched  upon  by  Frank 
D.  Peame  in  the  June  Radio  Age,  the  Roberts 
receiver  was  not  credited  to  Radio  Broadcast  as 
it  should  have  been,  since  the  Roberts  circuit 
was  first  published  by  that  magazine. 


New  DeForest  Tube  is 
Marketed 

JERSEY  CITY.— The  history  of  the 
radio  art  is  interwoven  with  intriguing 
romance  in  the  various  stages  of  its 
advancement,  unparalleled  by  that  of 
any  other  industry,  and  this  consistent 
phase  is  given  a  startling  proof  in  the 
latest  masterpiece  of  the  DeForest  Radio 
Company's  new  vacuum  tube,  now  on 
the  market. 

Termed  Type  DV-S — its  creators  have 
taken  the  somewhat  accidental  discovery 
of  a  biological  chemist  and  merged  with 
it  new  inventions  of  the  DeForest 
"audion"  laboratory,  in  the  construction 
of  what  is  said  to  be  the  long-sought 
Utopian  tube — one  of  perfect  insulation. 

Isolantite,  or  synthetic  quartz,  is  used 
for  the  base  of  this  tube,  and  the  romance 
of  its  discovery  dates  back  to  the  first 
years    of    the     World     War. 

Chief  Engineer  Roy  A.  Weagant  of  the 
DeForest  Radio  Company  found  that  an 
Isolantite  based  tube  decreased  grid 
plate  capacity  from  twelve  micro  micro- 
farads to  eight  or  less  at  frequencies 
from  100,000  to  10  million;  while  the 
tone  quality  remained  practically  con- 
stant, regardless  of  variations  in  fre- 
quency. 

The  DeForest  DV-5  is  a  standard  base, 
5  volt  storage  battery  tube,  and  said  to 
be  unsurpassed  as  an  audio  frequency 
amplifier  and  regenerative  detector.  It  is 
said  to  be  exceptional  equipment  for 
reflex  and  non-oscillating  radio  frequency 
circuits.  It  is  designed,  Mr.  Weagant 
said,  "to  use  high  plate  voltage  in  con- 
junction with  C  battery."  With  plate 
voltage  of  from  135  to  270,  and  the 
corresponding  C  voltage,  the  DV-5, 
used  as  an  audio  frequency  amplifier,  will 
give  approximately  double  the  volume  of 
any  present  tube,  with  the  sole  exception 
of  the  power  amplifier,  at  little  or  no 
increased    plate   current   consumption. 


All  Radiodom  Behind  Los 
Angeles  Show 

NEARLY  175  locally  and  nationally 
known  leaders  in  the  radio  industry 
have  joined  hands  here  for  the  purpose 
of  making  a  resounding  success  of  the 
Third  Annual  National  Radio  exposition, 
to  be  held  from  September  5  to  12  in 
the  new  Ambassador  auditorium. 

In  number  of  exhibit  spaces,  it  is 
announced  the  show  will  be  almost  in 
the  New  York  and  Chicago  class.  To 
insure  that  175  exhibits  could  be  entered, 
Waldo  T.  Tupper,  who  is  producing  the 
event  under  auspices  of  the  local  Radio 
Trades'  Association,  just  has  completed 
remodelling  a  heretofore  unfinished  wing 
of  the  auditorium. 

Before  the  work  of  remodelling  was 
finished,  nearly  the  entire  exhibit  space 
was  contracted  by  wholesalers,  retailers 
and  jobbers,  with  the  result  that  nearly 
the  entire  floor  area  of  the  exposition 
already  has  been  subscribed. 

With  the  previous  Los  Angeles  radio 
show  having  but  107  booths,  local  dealers 
and  fans  are  enthusiastic  over  the  strides 
made  by  this  one.  It  was  pointed  out 
by  Les  Taufenback,  acting  chairman 
of  publicity,  that  the  show  reflected  the 
popularity  of  radio  in  Southern  Cali- 
fornia. He  declared  the  home  life  here, 
coupled  to  the  appreciation  of  music 
and  the  finer  arts,  noticeable  throughout 
this  locality,  caused  this  district  to  be 
rated  as  one  of  the  principal  radio  centers 
of  the  United  States. 
*     Tested  and  Approved  by  RADIO  AGS     * 


Patented 

April 
21,  1925 

Other 
U.S.  and 
Foreign 
Patents 
Pending 


last  word  in 
tuning  devices 

When  a  micrometer  control  is 
so  delicately  geared  that  it  seeks 
out  and  brings  in  the  most  elu- 
sive stations  within  the  scope  of 
your  set  with  deadly  accuracy, 
and  with  ease,  we  feel  that  it 
fully  deserves  to  be  referred  to 
as  "the  last  word  in  tuning  de- 
vices". Such  is  the  Accuratune. 
Incidentally,  it  can  be  quickly 
substituted  for  ordinary  dials 
without  alteration  of  your  set. 

MYDAR  RADIO  CO. 

17  CAMPBELL  ST.,  NEWARK, N.J. 


\ 


£3,000  ^10,000  a  year 


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4513  Ravenswood  Ave,,  Dept.  9-8  Chicago,  111, 


Watch  for 

RADIO  AGE  on  the  air  again! 

About  September  20 ! 


54 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


^T  View  of  the  receiver  described  by  Mr. 
^»  Pearson,  laid  out  but  not  wired.  The 
economy  and  neatness  of  arrangement 
will  appeal  to  the  particular  set-builder . 


A  5-TubeTORO\D  COIL  Receiver 

A  SIMPLY  BUILT  SET  WITH  NO  EXTERNAL   INTERFERENCE 


SO  MUCH  interest  has  been  displayed 
in  the  application  of  the  new  self- 
contained  field  coils  since  the  pub- 
lication of  an  article  on  the  theory  and 
construction  of  the  coils  in  the  JULY 
issue  of  RADIO  AGE,  that  a  few  words 
on  the  actual  arrangement  of  the  com- 
plete receiver  would  seem  timely.  As 
you  will  remember,  the  essential  feature 
of  the  circloid  or  toroid  type  coil  is  the 
circular  magnetic  path  which  is  con- 
tained entirely  within  the  turns  of  wire 
so  that  no  stray  fields  are  generated 
to  cause  trouble  through  inter-stage 
coupling  when  used  as  transformers,  and 
so  that  the  coils  are  indifferent  to  external 
interferences,  which  commonly  cause  a 
loss  of  selectivity  with  the  more  common 
solenoid  coils. 

From  a  practical  standpoint,  as  viewed 
by  the  constructor,  the  most  important 
feature  is  the  ability  to  closely  space  the 
coils  on  a  short  panel  without  causing 
feed-backs  or  excessive  regeneration 
through  stray  fields.  We  do  not  need  to 
accurately  set  the  coils  at  some  definite 
and  usually  inconvenient  angle,  to  pre- 
vent coupling,  nor  do  we  require  elaborate 
methods  of  controlling  self-oscillations 
when  the  toroid  coils  are  used,  as  is  the 
case  with  the  more  common  coils.  Com- 
mercial five  tube  sets  are  in  production 
in  which  the  apparatus  is  mounted  com- 
plete on  a  7"  x  18"  panel,  and  as  you  all 
know,  this  is  about  as  small  a  space  as 
we  can  expect  to  use  for  a  five-tube 
tuned  radio  frequency  outfit.  For  the 
amateur,  however,  a  7"  x  21"  panel  is 
advisable,  not  for  fear  of  back-coupling, 
but  for  the  reason  that  the  parts  are  more 
accessible  for  wiring. 

After  many  trials  with  various  base- 
board and  sub-panel  constructions,  the 
arrangement  shown  by  the  accompanying 
photograph  was  found  the  most  practi- 
cable and  the  easiest  to  wire  up.  Here, 
all  of  the  parts  are  open  to  inspection  or 


By 
GEORGE  A.  PEARSON 

adjustment  with  the  least  loss  of  space 
and  they  also  present  a  symmetrical  and 
pleasing  appearance  to  the  critical  ama- 
teur constructor  who  is  as  much  concerned 
with  the  appearance  as  with  the  perform- 
ance. Another  feature  of  the  layout, 
and  by  no  means  the  least  important,  is 
the  length  of  the  wires,  which  is  reduced 
to  an  absolute  minimum  in  the  case  of 
the  grid  and  plate  leads,  which  are  of  such 
vital  importance  to  the  proper  operation 
of  a  receiver.  By  far,  the  greater  major- 
ity of  the  wires  are  from  4"  to  7"  long 
with  only  a  few  battery  leads  of  greater 
length. 

The  "Chassis" 
]V|  0  WOOD  baseboard  is  used  for  the 
1  i  support  of  the  apparatus.  The 
three  variable  tuning  condensers  and  the 
rheostats  are  mounted  on  the  panel  with 
the  coils  attached  to  the  backs  of  the 
condensers  by  metal  brackets  which  at 
once  act  as  a  support  and  as  a  means  of 
completing  one  of  the  connections  between 
the  coils  and  condensers.  All  of  the 
remaining  parts  such  as  the  tube  sockets, 
bypass  condensers,  and  audio  transformers 
are  mounted  on  a  bakelite  sub-panel  to 
the  rear  of  the  panel  and  coils.  This  is 
clearly  shown  in  the  photograph.  The 
panel  is  7"  x  21"  x  %°  while  the  sub- 
panel  is  of  the  same  length  and  only  3}i" 
wide.  Directly  to  the  rear  of  the  sockets 
and  attached  directly  to  the  sub-panel 
in  a  row  of  binding  posts  used  for  the 
connection  of  the  batteries,  antenna, 
ground  and  loud  speaker. 

A  rigid  connection  between  the  panel 
and  the  sub-panel  is  had  by  two  simple 
brass  brackets  made  of  sheet  brass  fi 
inch  wide  and  approximately  ^y-inch 
thick.      By    making    the    height    of    the 


brackets  equal  to  the  height  of  the  audio 
transformers,  the  latter  can  be  made  to 
support  the  sub-panel  near  the  center,  as 
shown.  When  in  place  in  the  cabinet, 
the  transformers  rest  on  the  floor  of  the 
cabinet-  thus  giving  a  rigid  support  at  all 
points  in  the  length  of  the  sub-panel. 
The  transformer  terminals  or  binding 
post  screws  pass  through  the  sub-panel 
and  are  capped  by  ornamental  nuts  which 
at  one  time  hold  the  transformers  in  place 
and  afford  a  means  of  making  short  con- 
nections between  the  tube  sockets  and  the 
transformers.  At  the  right,  the  output 
jack  is  supported  from  the  right  hand 
bracket. 

A  peculiar  arrangement  in  the  sequence 
of  the  sockets  was  made  necessary  by 
the  spacing  of  the  coils,  and  by  the  desir- 
ability of  short  wiring  connections, 
Starting  from  the  right  end  of  the  sub- 
panel,  the  first  tube  is  the  first  frequency 
tube,  then  the  second  audio  frequency 
tube,  the  second  radio  tube,  the  first 
audio  tube,  and  then  finally  the  detector 
tube  socket  at  the  extreme  left  where  the 
grid  leak  and  grid  leak  condenser  will 
be  seen.  Arranged  in  this  way,  the  grid 
post  of  each  socket  comes  directly  oppo- 
site to  the  grid  post  of  the  circloid  trans- 
formers, and  results  in   3-inch  grid  lines. 

Coil  Connections 

OWING  to  the  extreme  sharpness  of 
the  tuning,  two  circuit  transformer 
coils  cannot  be  used  throughout.  To 
reduce  this  extreme  sharp  tuning  so  that 
stations  can  be  more  easily  picked  up,  it 
was  found  desirable  to  install  a  single 
circuit  coil  in  the  antenna  circuit  at  the 
right  hand  end  of  the  panel.  This  is 
simply  a  continuous  winding,  tapped  at 
two  points  for  the  connection  of  the 
aerial,  with  connections  from  the  taps 
brought  to  two  antenna  posts  on  the 
rear  edge  of  the  sub-panel.  Connection 
(Turn  to  page  64) 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


53 


New  Season  to  Start 
with  Banquet 

The  Second  Annual  Banquet  of  the 
Radio  Industries  will  raise  the  curtain 
on  the  new  radio  season  on  the  evening 
of  September  16  at  the  Hotel  Commodore 
in  New  York  City. 

All  arrangements  are  under  way, 
committees  are  functioning,  radio  firms 
are  engaging  their  tables  and  from  all 
indications  this  banquet  will  set  a  stand- 
ard as  well  as  a  record  that  will  be  un- 
precedented. 

The  banquet  has  a  double  significance 
and  will  attract  a  double  audience. 
Actually  present  will  be  more  than  1000 
prominent  members  of  the  radio  in- 
dustry; officials  of  the  great  manu- 
facturing and  distributing  corporations, 
the  broadcasting  stations  and  all  the 
important  business  enterprises  that  have 
to  do  with  radio.  Figuratively  present 
will  be  the  great  radio  public,  tuned  in 
to  the  magnificent  entertainment  which 
will  be  brought. 

Because  of  the  great  influence  wielded 
by  the  members  of  the  associated  organi- 
zations under  whose  auspices  the  dinner 
will  be  given,  the  finest  radio  entertainers 
in  the  country  will  broadcast  direct 
from  the  banquet  hall.  The  entire  pro- 
gram for  broadcasting  is  being  built  on  a 
basis  of  delighting  the  public  which 
stays  at  home.  It  will  be  undoubtedly 
the  sort  of  treat  which  only  the  combined 
efforts  of  the  entire  radio  industry  could 
possibly  bring  about.  The  speakers, 
like  the  entertainers,  will  all  be  nation- 
ally known  figures. 

The  associations  which  are  sponsoring 
the  banquet  include  the  National  Associa- 
tion of  Broadcasters,  the  Radio  Manu- 
facturers Association,  the  Independent 
Radio  Manufacturers  Association,  the 
National  Radio  Trade  Association,  the 
Talking  Machine  and  Radio  Men,  Inc., 
the  Electrical  Supply  Jobbers  Associa- 
tion, the  Pacific  Radio  Trade  Associa- 
tion, the  Electric  Club  of  Chicago,  the 
Radio  Magazine  Publishers  Association, 
the  American  Radio  Association,  the 
Radio  Announcers  of  America,  the  Radio 
Tube  Manufacturers  Association,  the 
Bakelite  Moulders  Association,  the  Wis- 
consin Radio  Trade  Association;  the 
Central  States  Radio  Jobbers  Associa- 
tion, the  St.  Louis  Radio  Trade  Associa- 
tion, the  Radio  Trade  Association  of 
Michigan,  the  Northwest  Radio  Trade 
Association  and  the  Radio  Writers 
League. 


Radio  Shows  For  This 
Fall 

Aug.  22-29,  Pacific  Radio  Ex....San  Francisco,  Cal. 

Sept.  5-12,  National  Radio  Ex.. ..Los  Angeles,  Cal. 

Sept.  6-12,  National  Radio  Ex..  ...New  York,  N.  Y. 

Sept.  14-19,  Second  Annual  Radio  World's 

Fair New  York,  N.  Y. 

Sept.  14-19,  Pittsburgh  Radio 

Show Pittsburgh,  Pa. 

Sept.  14—19,  Canada  Radio  Show Winnipeg,  Can. 

Sept.  23-27,  International  Radio 

Es_ Atlantic  City,  N.  J. 

Sept.  28-Oct.  3,  National  Radio  Ex Chicago,  111. 

Oct.  5-10,  Second  Annual  N.  W.  Radio 

Ex-.St.  Paul  and  Minneapolis,  Minn. 

Oct.  5-10,  Radio  Show  and  Conven- 
tion  Washington,  D.  C. 

Oct.  12-17,  St.  Louis  Radio  Show_  ..St.  Louis,  Mo. 

Oct.  12-17,  Boston  Radio  Show Boston,  Mass. 

Oct.  17-24,  Radio  Show Brooklyn,  N.  Y. 

Oct.  19-25,  2nd  Annual  Radio  Ex_.Cincinnati,  Ohio 

Nov.  2-7,  2nd  Annual  Radio 

Show..- Toronto,  Ont.,  Can. 

Nov.  3-6,  Detroit  Radio  Show. Detroit,  Mich. 

Nov.  9—15,  Milwaukee  Radio  Ex.. Milwaukee,  Wis. 

Nov.  17-22.  Fourth  Annual  Show Chicago,  111. 


Detroit    Radio    Manufacturer 
Organizes   in   Canada 

Announcement  has  just  been  made  of 
the  organization  of  the  Dongan  Electric 
Manufacturing  Company  of  Canada, 
Ltd.,  with  factory  and  offices  at  Walker- 
ville,  Ontario.  This  is  an  important 
step  in  Canadian  electrical  and  radio 
circles  and  is  one  more  evidence  of  the 
Dominion's  consumption  of  high  grade 
radio  merchandise. 

The  Dongan  Electric  Manufacturing 
Company  with  headquarters  in  Detroit 
has  been  famous  for  fifteen  years  for  its 
line  of  transformers  and  ammeters. 
Today  this  company  is  the  largest  manu- 
facturer of  bell-ringing  transformers  in 
the  world.  Low  voltage  transformers 
and,  of  recent  years,  oil  burner  trans- 
formers share  a  large  portion  of  the 
company's  production. 

During  the  last  few  years  a  national 
reputation  has  been  made  for  quality 
parts  in  the  rapidly  growing  radio  field. 
At  present  Dongan  is  supplying  35 
different  Receiving  Set  Manufacturers 
with  audio  transformers.  In  addition 
to  audio  transformers  Dongan  builds 
voltmeters  both  for  the  set  manufac- 
turers and  the  jobbing  trade. 

Lakeside  Type  M  Loud 
Speaker 

The  most  essential 
qualities  of  a  loud 
speaker  horn  are: 
clarity,  volume  and 
faithful  reproduction 
of  tone.  It  is  diffi- 
cult to  say  which  of 
these  exceeds  in  im- 
portance but  when 
using  a  Lakeside  loud 
speaker,  it  is  not  nec- 
essary to  solve  the 
problem  for  all  three 
are  embodied  in  the 
§  same  horn. 

The  volu  me  obtain- 
able is  all  that  anyone  could  wish.  Ad- 
ded to  this  is  the  fact  that,  while  it  gives 
a  good  loud  tone,  the  cast  aluminum 
goose  neck  preserves  the  natural  quality 
and  clarity  prevents  unnecessary  vibra- 
tion which  would  tend  to  distort  it.  In 
this  way  you  are  assured  of  faithful  re- 
production of  each  and  every  tone. 

New  Transformers  Marketed 
by  Silver-Marshall 

An  announcement  to  set-builders, 
experimenters  and  the  trade,  has  just 
been  made  by  Silver-Marshall,  Inc.,  that 
henceforth  their  long  wave  transformers 
will  be  supplied  in  moulded  bakelite 
cases  rather  than  in  the  aluminum  hous- 
ings previously  supplied.  Not  only  is 
the  appearance  of  the  transformers 
greatly  enhanced,  but  their  efficiency 
has  been  very  materially  increased,  ac- 
cording to  statements  made  by  McMudro 
Silver,  designer  of  the  Silver  Supers  and 
the  Super-Autodyne. 

The  new  transformers,  still  to  be  known 
as  the  210  intermediate  and  211  filter, 
given  an  amplification  approximately 
25  per  cent  higher  for  the  intermediates, 
and  40  per  cent  higher  for  the  filter,  than 
did  the  older  models.  The  manufacture 
of  the  401  transformer  unit,  containing 
three  transformers,  has  been  abandoned, 
since  due  to  its  metal  case,  it  was  im- 
possible to  improve  its  efficiency  to  com- 
pare favorably  with  the  bakelite-cased 
instruments,  despite  the  fact  that  the 
transformer  coils  themselves  in  each 
case    were    identical. 

*     Tested  and  Approved  by  HADIO  AGI     * 


CONDJ^^ftS 

A^'^-&rj£,^  "None  better  made! 
Conform  to  Bureau 
of  Standards  specifi- 
cations for  lowest 
losses.  Automatic 
bearing  take-up  and 
rugged  construction 
assure  permanent 
alignment.  All  capao 
ities— plain,   vernier. 

STANDARD  FuUy  guaranteed. 


Duplex  Matched  Condensers 
Afford  Uniform  Dial  Settings 


Always 
Read    > 
Alike 


to  Log 


Or  eliminate  logging  —  Dial  by  call 
letters  or  wave  lengths.  Specially  tested 
and  guaranteed.  Matched,  packed  and 
sealed,  to  remain  unopened  until  used. 

Literature  on  request 

DUPLEX  CONDENSER  &  RADIO  CORP. 

I  Flatbush  Ave.  Extension,  Brooklyn,  N.Y. 


Df    the 


f  the 


Lack 

refinements  o: 
Duplex  Standard  but 
are"best  at  tbe  price" 
Ideal  for  portable  sets. 
All  capacities  — plain 
and  vernier. 


JUNIOR 


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See  Page  60 


56 


RADIO'AGE  for  September,  1925 


The  Magazine  of  the  Hour 


* 


The 
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AMPERITE  controls  the  flow  of  current  through 
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life.  Lowers  set  cost.  Proved  and  adopted  by  more 
than  50  set  manufacturers.  For  perfect  filament  con- 
trol you  must  use  AMPERITE.  $1.10  every  where. 

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Standard  Radio  Receivers 

Sometime  ago  RADIO  AGE  inaugurated  a  new  department  called  "Know 
Before  You  Buy,"  to  serve  as  a  guide  to  the  prospective  radio  purchaser  in 
deciding  on  the  receiver  best  suited  to  his  individual  needs.  Fans  throughout 
the  country  have  shown  a  keen  interest  in  this  new  feature,  and  accordingly  it 
is  being  made  a  feature  of  all  numbers  of  RADIO  AGE.  Readers  are  invited 
to  write  us  concerning  the  sets  in  which  they  are  interested,  and  manufacturers 
also  are  asked  to  send  us  material  describing  their  sets. 


New  Pfanstiehl  Line 


/"iNE  of  the  features  of  the  new  Pfan- 
'-'  stiehl  line  of  radio  receivers  for  next 
year  has  just  been  completed  by  Carl 
Pfanstiehl. 

This  is  a  low  priced  five  tube  receiver, 
two  dials,  housed  in  a  solid  walnut 
cabinet  with  sloping  panel. 

Price  will  be  §85.00  and  delivery  will 
be  made  at  any  time. 

There  are  five  outstanding  features  in 
the  new  receiver: 

1.  Two  dial  control  was  made  possible 
through  the  development  by  Mr.  Pfan- 
stiehl, of  an  accurate  thick  plate  straight- 
line-frequency  condenser. 

2.  A  small  amber  light  will  burn  as 
long  as  the  set  is  operating. 

3.  The  large  station-finder  shows  the 
dial  readings  for  all  wavelengths  and 
makes  tuning  very  simple. 

4.  Mr.  Pfanstiehl  has  not  employed 
the  method  of  dampening  oscillations 
through  absorption  of  energy,  common  to 
low  priced  receivers,  but  has  made  use 
of  a  system  which  prevents  the  generation 
of  oscillations  in  the  first  place. 

5.  Two  control  dials,  or  rheostats,  one 
for  volume  and  one  for  tone,  make  it 
possible  with  this  receiver  to  secure  long 
distance  and  yet  maintain  quality  of 
tone.  The  verniers  beneath  the  large 
tuning  dial  also  contribute  to  accurate 
distance     getting. 


Type — Pfanstiehl  non-oscillating  sys- 
tem of  tuned  radio  frequency. 

Tubes— Radio  Amplifier  (2).  U.  V.- 
201-A  and  C-301-A.  Audio  Amplifier 
(2).     Detector   (1). 

Battery — "A"  Storage,  6  volts. 

Battery — "B"   90  volts. 

Controls— Tuning,    (2);   Tube    (2). 

Antenna — Indoor     and     Outdoor. 

Dimensions — 22x10x14. 

Weight — 16  pounds. 

"Features" 

Two  dial  control  made  possible  through 
Mr.  Pfanstiehl's  newly  designed  2  gang 
condenser,  which  is  a  scientific  achieve- 
ment in  accuracy. 

Orange  light  on  panel  which  burns 
while  set  is  operating. 

A  large  and  very  easily  read  station- 
finder  (5  1-2  inches  long). 

Both  volume  and  tone  control  rheo- 
stats, which  make  possible  greater  dis- 
tance than  Pfanstiehl  had  last  year. 

Vernier  control  of  tuning  means  accur- 
acy, especially  for  distance. 

Handsome  cabinet  of  solid  walnut 
with  sloping  panel  (panel  of  walnut 
material — very   stunning.) 

All  the  low  priced  receivers,  except 
this  one,  place  the  coils  close  to  the  con- 
densers and  stop  oscillations  through 
absorption   of   energy.    (Turn  to  page  57) 


In  response  to  many  requests,  H.  Frank  Hopkins 
will  tell  you  how  to  build  an  "Improved  Slide 
Wire  Bridge"  for  Measuring  Capacity,  Imped- 
ance and  Other  Formulae,  in  the  All-Star  Octo- 
ber RADIO  AGE.  On  the  stands  September  15 
with  an  unusual  array  of  features. 


#     TttUd  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  September,  1925 

Miessner  Bat-ry-less  Receiver 

(Continued  from  page  56) 


The  Magazine  of  the  Hour 


57 


NOT  since  the  invention  of  the  three- 
element  vacuum  tube  that  made 
present-day  radio  broadcasting  possible 
has  there  been  so  much  work,  energy,  and 
thought  applied  to  the  improvement  of 
radio  apparatus. 

Engineers  have  applied  themselves  to 
sets  that  would  give  volume,  get  dis- 
tance, tune  selectively,  and  which  would 
be  simple  to  operate.  They  haveelimi- 
nated  one  after  the  other  all  of  the  little 
imperfections  that  stood  in  the  way  of 
perfect  radio  enjoyment,  with  the  excep- 
tion of  battery  elimination. 

Batteries  are  not  only  a  large  cost  in 
the  original  price  of  a  radio  outfit,  they 
are  also  one  of  the  largest  expenses  in  con- 
nection with  the  upkeep,  it  is  claimed. 
Hence,  many  have  been  the  attempts  to 
remove  the  need  for  batteries. 

Due  to  the  peculiarities  the  problem 
involves,  it  has  been  a  greater  task  than 
anticipated  by  some  of  the  largest  labora- 
tories of  the  country.  True,  battery-less 
receivers  have  been  built,  which  eliminate 
batteries  from  the  circuit.  It  is  com- 
paratively easy,  for  instance,  to  design  a 
receiver  that  will  work  satisfactorily  on 
direct  current  lines,  for  in  that  case,  the 
electric  current  is  already  in  a  form  suit- 
able for  use,  and  requires  no  conversion 
process.  It  is  in  the  operation  of  radio 
sets  from  alternating  current  circuits  that 
most  attempts  have  failed.  And  95%  of 
the  homes  in  the  United  States  equipped 
with  electricity  have  an  alternating  cur- 
rent supply.  The  A.  C.  power,  if  used 
directly  on  ordinary  sets  produces  an 
extremely  loud  and  disagreeable  buzzing 
sound  which  bars  quality,  tone,  and  clear- 
ness, and  destroys  good  reception. 

In  an  effort  to  solve  the  troubles  in- 
herent in  most  of  the  sets  using  the  elec- 
tric light  socket  as  a  source  of  power, 
Benjamin  F.  Miessner,  an  acoustical  and 
radio  engineer  with  a  record  of  achieve- 
ments, has  developed  a  battery-less  re- 
ceiver which  is  claimed  to  place  this 
type  of  receiver  in  a  class  above  the 
battery  operated  set. 

Heretofore,  there  had  been  no  thought 
of  building  the  current  conversion  device 
in  the  same  cabinet  as  the  radio  instru- 
ments, because  this  only  added  to  the 
hum  and  noises  caused  by  the  use  of 
socket  current.  Mr.  Miessner's  new  set  has 
been  so  thoroughly  designed  that  he  does 
not  hestitate  to  locate  conversion  and  radio 


circuits  side  by  side  behind  the  same  panel. 
The  user  of  this  new  set  will  not  realize 
that  special  apparatus  is  required  to  ac- 
complish this  wonderful  work  of  perfect 
conversion,  as  it  has  been  reduced  to  such 
perfect  and  compact  form.  To  all  ap- 
pearances, this  six-tube  set  is  no  different 
from  others,  excepting  that  it  requires  no 
extra  attachments  for  battery-elimination, 
no  loud  speaker,  or  batteries.  In  opera- 
tion, it  is  no  different,  and  possibly 
simpler  than  most  sets.  A  loud  speaker, 
which  is  acoustically  perfect,  is  embodied 
in  the  set  itself,  thus  making  the  receiver 
a  complete  unit. 

The  elimination  process  is  so  complete 
that  the  set  not  only  operates  with  a 
built-in  loud  speaker,  but  is  provided  with 
a  head-telephone  receiver  connection 
through  which  the  listener  may  receive 
programs  without  the  slightest  trace  of 
hum.  This  is  not  only  a  supreme  test  as 
to  the  perfection  of  the  conversion  system 
but  is  also  a  feat  that  has  never  been  pos- 
sible with  a  set  operating  without  batteries. 

Six  standard  commercial  vacuum  tubes 
perform  the  functions  of  current  con- 
version, amplification  and  detection.  The 
current  consumption  is  eight  watts. 
This  brings  the  cost  of  operating  this  set 
down  to  one-tenth  of  a  cent  per  hour, — 
a  sum  one-twentieth  that  of  the  cost  of 
operating  an  ordinary  electric  iron. 

Although  the  electric  conversion  sys- 
tem is  built  into  the  same  cabinet  as  the 
receiver,  it  has  nothing  to  do  with  the 
type  of  circuit  used  for  radio  reception. 
This  set  is  equipped  with  a  standard 
improved  form  of  receiving  circuit  using 
four  controls.  Its  selectivity,  intensity, 
distance  and  volume  are  equal  to,  and 
in  many  cases  superior  to  average  re- 
ceivers on  the  market.  The  quality  is 
unsurpassed,  the  loud  speaker  volume  be- 
ing more  than  adequate,  and  perfectly 
controllable. 

Everything  needed  for  operation  is  con- 
tained in  one  small  cabinet,  which  is 
battery-less,  consequently  without  the 
cost  and  trouble  that  goes  with  battery 
operation. 

Benjamin  F.  Miessner  has  long  worked 
in  radio  and  acoustics.  He  was  formerly 
electrical  engineer  with  John  Hammond, 
of  torpedo  radio  control  fame.  The  set 
will  be  shortly  placed  on  the  market  by 
the  Miessner  Radio  Corporation. 
(Turn  to  page  58) 

*     Tested  and  Approved  by  RADIO  AGE     * 


Takes  the  MYSTERY 
out  of  RADIO! 


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58 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


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Name .Age 

Street 

City State 


Standard  Radio  Receivers 

(Continued  from  page  57) 

De  Forest  Claims  Non-Radiating  Circuit 


'"PHE  long  sought  non-radiating  and  non- 
-*-  oscillating  circuit — the  goal  of  the  greatest 
exponents  of  the  radio  art  for  the  past  five 
years,  has  finally  been  successfully  achieved, 
it  is  said,  in  the  new  De  Forest  F-5  type  that 
will  be  placed  on  the  market  soon  in  a  port- 
able model. 

This  circuit  is  a  five- 
tube  tuned  radio  fre- 
quency receiver  of  im- 
proved design  with  a 
wavelength  range  of  220 
to  550  meters.  It  con- 
sists of  two  stages  of 
tuned  radio  frequency 
amplification  with  tuned 
input  to  the  detector  and 
two  stages  of  transformer 
coupled  audio  frequency 
amplification.  Chief  en- 
gineer R.  A.  Weagant  of 
the  De  Forest  Company 
has  departed  from  usual 
practice  in  design  of  the 
radio  frequency  trans- 
formers to  the  use  of 
Astatic  Radio  Frequency 
Coils,  which  confine  stray 
magnetic  fields  to  a  mini- 
mum. 

The  new  circuit,  Mr. 
Weagant  said,  has  great 
distance-getting  qualities 
while  at  the  same  time 
preserving  ample  selectivity.  Particular  atten- 
tion has  been  given  to  mechanical  simplicity 
and  ruggedness  to  attain  what  is  believed  to 
be  an  almost  "fool-proof"  set.  In  addition  it 
is  equipped  with  new  shock  absorber  sockets 
to  prevent  damage  to  the  tubes  under  "field" 
conditions. 

The  F-5  Portable  is  entirely  self  contained. 
The  antenna  and  ground  wires,  the  new  De 
Forest  cone  loud  speaker,  which  is  said  to  give 
the  most  truthful  reproduction  of  any  on  the 
market,  and  all  batteries  are  compactly  housed 
in  an  artistic  and  durable  du  Pont  case  fitted 
with  a  permanent  carrying  handle  of  con- 
venient   form. 

The  portable  measures  15J4  inches  deep 
by  14  inches  wide  and  11  high  when  closed 
for  carrying  and  weighs  but  37  pounds  com- 
plete with  batteries.  150  feet  of  flexible 
antenna  wire  are  wound  on  a  built-in  aluminum 
reel  of  original  design  connected  to  the  re- 
ceiving circuit  in  addition  to  15  feet  of  flexible 
ground  wire  conveniently  assembled  in  a 
spring  clip  of  original  design. 

Circuit  of  De  Forest  F-5   Portable 

From  the  schematic  diagram,  it  will  be  seen 
that  the  circuit  consists  of  two  stages  of  tuned 


radio  frequency  amplification,  detector  with 
tuned  input  and  two  stages  of  transformer 
coupled  audio  frequency  amplification. 

The  incoming   radio   energy  is  intercepted 
by  the  antenna,  which  is  connected  to  either 
of  the  binding  posts  marked:  "Ant.  1,"  "Ant. 
2,"  and  "Ant.  3,"  as  con- 
ditions call  for. 

The  .0005  mfd.  vari- 
able condenser  No.  2 
tunes  the  secondary  of 
transformer  No.  1  and 
the  grid  or  input  of  first 
radio  frequency  tube  No. 
3  to  resonance  with  the 
desired  wavelength.  From 
the  plate  or  output  of 
tube  No.  3,  the  ampli- 
fied energy  passes  through 
the  primary  of  transformer 
No.  4,  and  is  transferred 
by  electro  magnetic  in- 
duction to  the  secondary 
winding,  which  is  tuned 
to  resonance  by  the  .0005 
mfd.  variable  condenser 
No.  5,  whence  it  is  im- 
pressed upon  the  grid  of 
the  second  radio  frequency 
tube  No.  6.  The  further 
amplified  energy  then 
passes  through  transform- 
er No.  7,  the  secondary  of 
which  is  tuned  by  the 
.0005  mfd.  variable  condenser  No.  8,  to  the  de- 
tector tube  No.  9,  where  it  is  rectified  or 
changed  into  an  audio  frequency  current.  The 
audio  frequency  energy  now  passes  to  the  pri- 
mary of  the  first  audio  frequency  transformer 
No.  10  and  is  transferred  by  induction  to  the 
secondary  coil,  whence  it  is  applied  to  the  grid 
of  the  first  audio  frequency  tube  No.  11.  From 
the  plate  or  output  of  tube  No  .11,  the  amplified 
rjurrent  passes  through  the  second  audio  fre- 
quency transformer  No.  12  to  the  grid  of  the 
second  audio  frequency  tube  No.  13.  The 
greatly  amplified  current  then  passes  from  the 
plate  or  output  of  tube  No.  13  to  the  loud 
speaker,  which  is  connected  to  jack  No.  15, 
where  it  is  converted  into  an  audible  signal 
of   great   volume. 

A  jack  No.  14  is  provided  in  the  first  audio 
frequency  circuit  for  the  use  of  head-phones. 
The  "A"  battery  current  to  the  filaments 
of  the  radio  frequency  tubes  No.  3  and  No.  6 
is  controlled  by  the  rheostat  No.  17,  and  to 
the  filaments  of  the  detector  and  audio  fre- 
quency tubes  No.  9,  No.  11  and  No.  13  re- 
spectively by  the  rheostat  No.  16. 

Bypass  condensers  are  placed  across  the 
primary  of  first  audio  frequency  transformer 
No.  10  and  loud  speaker  jack  No.  15. 


The  wiring  diagram  for  the  new  DeForesl  Receiver,  which,  it  is  claimed,  achieves  the  goal 
of  Non-Radiation  and  Non-Oscillation. 

Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


59 


How  the  Carrier  Wave 
"Does  its  Stuff" 

(Continued  from  page  20) 

Referring  to  Figure  3,  at  "A"  a  crystal 
detector  has  been  inserted  in  circuit  with 
the  aerial,  phones  and  ground.  A  crystal 
detector  has  the  property  of  allowing  a 
current  in  one  direction  to  pass  through 
it  freely,  but  will  not  allow  it  to  pass  so 
easily  in  the  other  direction.  The  re- 
sultant change  in  the  wave  passing 
through  it  is  shown  to  the  right  of  it  at 
"B."  It  will  be  noticed  that  the  wave 
comes  in  its  true  form  until  it  reaches  the 
detector,  at  which  point  it  is  almost  com- 
pletely rectified;  that  is,  the  part  on  one 
side  of  the  zero  line  is  nearly  eliminated, 
because  that  part  is  in  the  direction  which 
will  not  pass  freely  through  the  crystal. 

The  result  then  is  as  before  mentioned; 
a  direct  current,  or  nearly  so,  produced  by 
the  part  of  the  wave  which  does  not  get 
through  the  crystal.  "C"  shows  how  the 
diaphragm  refuses  to  respond  to  the  un- 
rectified  wave  and  "D"  shows  how  the 
diaphragm  is  affected  by  the  direct  cur- 
rent after  it  passes  through  the 
crystal. 

Now  we  have  caused  the  diaphragm  to 
move,  but  still  we  get  no  sound  because 
it  remains  in  the  position  shown  and 
nothing  makes  it  vibrate.  Now  we  know 
that  the  wave  coming  from  the  broad- 
casting station  is  as  shown  at  "A," 
Figure  4.  When  a  sound  is  produced  in 
front  of  the  microphone  the  peaks  of 
some  of  the  oscillations  are  varied,  as 
shown  at  "B."  A  line  now  traced  over 
the  tips  of  the  oscillations  will  make  many 
strange  shapes  as  shown.  Just  what 
shape  of  envelope,  as  it  is  called, 
will  be  produced,  will  depend  upon 
the  vibrations  of  the  microphone 
diaphragm. 

The  wave  shown  at  "B"  is  MODU- 
LATED, or  changed  in  shape  from  its 
original  shape  shown  at  "A,"  and  now 
takes  on  a  form  which  is  entirely  con- 
trolled by  the  microphone  and  may  now 
be  as  shown  at  "B,"  or  any  other  of  a 
million  or  more  shapes.  Now  if  this 
modulated  wave  is  passed  through  the 
detector  shown  in  Figure  3,  it  would  keep 
the  same  form  as  shown  at  "B,"  Figure  4, 
up  to  the  detector,  and  after  passing 
through  the  detector,  it  would  take  up 
the  form  of  one  half  of  "B,"  Figure  4, 
and  the  diaphragm  of  the  phones  would 
vibrate  according  to  the  shape  of  the 
rectified  wave  shown  at  "C,"  Figure  4, 
because  a  line  drawn  across  the  peak  of 
the  wave  would  not  be  straight,  indicat- 
ing a  direct  current  of  unvarying  strength, 
but  would  show  an  uneven  line,  indicat- 
ing that  the  current  varied  and  naturally 
the  diaphragm  would  follow  these  varia- 
tions. 

The  question  may  arise  as  to  just  how 
the  shape  of  the  wave  can  influence  the 
diaphragm  of  the  phones.  As  the 
strength  of  a  current  produced  in  a  wire 
by  lines  of  force  cutting  through  it  de- 
pends upon  the  number  of  lines  cutting 
and  the  speed  with  which  they  cut,  it  is 
obvious  that  if  the  amplitude  of  the  wave 
is  reduced,  that  part  of  the  wave  will  not 
carry  as  many  lines  as  the  part  which  has 
not  been  reduced.  Therefore  the  ampli- 
tude of  the  different  parts  of  a  modulated 


"it 


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NO  excuse  now  for  not  having  a 
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This  feature  follows  the  discovery 
of  a  new  inductance  principle  that 
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Circloids  are  the  backbone  of  the 
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3.  Increased  selectivity.  Circloids 
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4.  Finer  tone  quality.  The  self- 
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60 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


^gge^^n^gg^^^ggigpggigi 


JEFFERSON 

TRANSFORMERS 


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Would  you  be  satisfied  to  have  your 
butcher  make  you  a  suit  of  clothes? 


"\A7E  ASK  this  question  as 
a  parallel  to  an  existing 
situation  in  radio.     We  refer 
to  radio  transformers. 

Transformers — vital  to  success- 
ful radio  reception — are  one  of  the 
most  highly  specialized  of  all 
radio  products.  That's  a  good 
thing    to    remember. 

Whether  you  are  building  or 
buying  a  set,  be  sure  the  trans- 
formers are  made  by  specialists — 
by  some  one  experienced  in  making 
this  highly  specialized  product. 

Long  before  radio  was  born, 
the  Jefferson  Electric  Manufac- 
turing   Company    specialized  in 


Jefferson  Electric  Mfg.  Co. 


transformers.  Today  we  are  the 
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Is  it  any  wonder  that  Jefferson 
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complete  transformer  satisfac- 
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wave  will  produce  a  current  varying  in 
strength  according  to  the  shape  of  the 
wave. 

Another  point  which  may  not  be  clear, 
is  just  how  these  lines  of  force  cutting 
through  an  aerial  wire  which  is  practically 
an  open  circuit,  can  produce  a  current 
when  there  is  no  complete  circuit,  for  the 
aerial  extends  into  the  air  and  stops  there. 
This  is  explained  by  the  capacity  of  the 
aerial  and  ground.  It  will  be  remembered 
that  the  time  of  one  oscillation  is  only  a 
small  part  of  a  second  so  that  the  lines 
cut  through  the  aerial  in  one  direction  for 
less  than  one  millionth  of  a  second  before 
it  reverses  and  the  lines  cut  in  the  other 
direction. 

This  can  be  likened  to  Figure  7,  which 
shows  a  water  analogy.  If  a  water  wheel 
is  enclosed  as  shown  and  the  end  of  the 
pipe  is  closed  as  shown  at  "A"  Figure  6, 
and  water  is  passed  into  the  pipe,  the 
water  would  hardly  reach  the  wheel  be- 
fore it  lost  its  power  due  to  the  air  pres- 
sure against  it.  However,  if  instead  of 
sealing  the  end  of  the  pipe,  a  large  tank 
is  attached  to  it,  considerable  water 
would  flow  past  the  wheel  before  the  pres- 
sure of  the  tank  would  equal  the  pressure 
of  the  incoming  water. 

This  arrangement  is  shown  at  "B," 
Figure  6.  Thus  the  wheel  at  "B"  would 
turn  several  revolutions  before  the  ca- 
pacity of  the  tank  is  satisfied. 

The  same  may  be  said  of  the  aerial. 
With  a  short  aerial,  only  short  impulses 
could  be  produced  in  it  before  it  became 
charged,  but  with  a  long  one,  an  impulse 
of  longer  duration  could  be  effective. 

As  a  matter  of  fact,  the  time  of  cutting 
in  one  direction  is  so  small  that  almost 
any  aerial  has  enough  capacity  to  allow 
enough  movement  of  current  to  affect  the 
circuit  and  at  each  reversal,  the  capacity 
unloads  and  charges  up  again  in  the  op- 
posite direction,  so  then  if  an  inductance 
is  included  in  the  aerial  circuit,  even 
though  the  circuit  is  open,  a  highly 
oscillating  current  of  short  duration  can 
be  made  to  move  in  it. 


"Three  Big  Things" 

The  adjustable  grid  leak  which  the 
Colytt  Laboratories  of  Chicago  are  put- 
ting on  the  market  may  have  more  than 
three  things  to  commend  it  to  the  radio 
fan,  but  the  manufacturers  have  not  over- 
looked one  big  thing  in  merchandising, 
and  that  is  the  proper  display  of  the 
article. 

Put  up  as  this  grid  leak  is,  it  is  con- 
venient for  the  dealer  as  well  as  his  cus- 
tomer. It  helps  the  dealer,  too,  by  telling, 
plainly  and  attractively,  what  it  is  and 
what  it  sells  for.  This  in  turn  is  a  help  to 
the  customer,  for  it  gives  him  the  infor- 
mation he  wants  and  which  a  busy  clerk 
cannot  always  find  time  to  do. 

This  grid  leak,  by  the  way,  is  adjustable 
and  designed  so  that  it  tunes  tubes  of  any 
kind,  and  maintains  its  calibration  prac- 
tically constant — only  extreme  disturb- 
ance will  necessitate  a  readjustment. 

This  fact,  coupled  with  its  neat  ap- 
pearance and  single  hole  mounting,  with 
thumb  nut,  bids  fair  to  make  it  a  very 
popular  addition  to  the  panel. 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  September,  1925 


What  Kind  of  Sets  Do  the 
Fans  Want? 

(Continued  from  page  40) 
Crystals  Also  Gain 

SPEAKING  of  city  receiving  condi- 
tions makes  me  think  of  the  increas- 
ing number  of  amplified  crystal  detector 
sets  now  in  operation.  They  have  but 
little  radius  of  action,  say  50  miles  at 
the  outside,  but  they  bring  in  local  signals 
with  beautiful  clarity  and  fidelity  of 
tone.  In  general,  the  layout  consists 
of  a  sharp  tuning  crystal  detector  with 
one,  two  or  three  audio  stages  added. 
Such  a  set  with  two  transformer  stages 
gives  excellent  results  on  a  loud  speaker, 
while  three  resistance  coupled  stages 
give  better  volume  and  better  clarity, 
particularly  when  the  resistance  coupled 
tubes  are  given  a  strong  bias  by  means 
of  a  "C"  battery.  If  you  are  not  a  DX 
fan,  and  simply  enjoy  the  perfect  repro- 
duction of  local  signals,  then  this  stunt 
is  well  worth  trying. 

A  sharp  crystal  tuner,  a  stage  of  low 
ratio  transformer  audio  coupling,  and 
two  stages  of  resistance  coupled  with 
the  last  stage  consisting  of  two  tubes  in 
parallel,  will  develop  qualities  in  your 
loud  speaker  that  you  never  would  have 
considered  possible.  You  will  find  that 
the  loud  speaker  has  been  condemned 
for  distortion  that  in  many  cases  really 
exists  in  the  receiver.  It  takes  a  circuit 
such  as  the  above  to  show  this  up. 

Another  combination  that  gives  good 
results  consists  of  a  stage  of  radio  fre- 
quency, crystal  detector,  and  one  or  two 
stages  of  audio.  This  is  not  quite  so 
clear  as  the  straight  crystal  detector 
system  with  added  audio,  but  it  has  a 
greater  range  than  the  amplified  audio 
system  and   tunes  somewhat   sharper. 

We  will  ask  all  of  you  to  send  in  your 
votes  on  this  most  important  subject 
dealing  with  the  number  of  tubes  em- 
ployed in  your  ideal  receiver.  Use  the 
blank  appearing  in  the  July  issue  of 
RADIO  AGE  or  else  simply  send  us  a 
letter  with  the  advice.  The  final  results 
will  be  printed  in  the  October  number 
of  RADIO  AGE,  which  will  be  in  ample 
time  for  the  coming  season.  Consider 
quality  and  tube  economy  as  well  as 
distance,  volume  and  price. 


The  Magazine  of  the  Hour 


61 


Buy  your  RADIO  AGE  ANNUAL 
now!  The  edition  is  limited — $1.00 
a  copy. 

ROSS  I 

fTHE  COUNTRY  WITH         f 

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Something  decidedly  new,  different,  and  better  has 
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The  new  Tungar  charges 
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Last  thing  at  night — concert  over — time  to  lock 
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The  Tungar  is  simple  — makes  no  disturbing 
noise.  And  the  low  cost  of  Tungar  recharging 
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Increase  Distance,Volume,  Clarity 

"Colytt"  adjustable  grid  leak  improves  receiving.  Gives 
proper  value  of  leak  in  grid  circuit,  and  holds  it.  Simple, 
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wire,  only  extra  part,  circuit  and  complete, 
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*     Tested  and  Approved  by  RADIO  AGE     * 


62 


RADIO  AGE  for  September,  1925 


The  Jewell 
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*     Tested  and  Approved  by  RADIO  AGE     * 


The  Magazine  of  the  Hour 

A  Touch  of  the  Old 
World  at  WMBB 

(Continued  from  page  29) 
to  stay."  Clyde  Hager  takes  three  dia- 
logue parts,  the  Irish  policeman,  the  Irish 
washerwoman,  and  Pedro,  the  organ  grin- 
der. There  is  also  Little  Orphan  Annie 
and  Tony,  the  janitor's  boy.  The  playlet, 
with  music  throughout,  presents  a  quaint 
bit  of  humor  which  could  appropriately 
take  place  in  the  Bowery. 

"Uncle  Tom"  There,  Too 

'TWERE  is  also  "Uncle  Tom's  Tunes," 
-*-  a  musical  feature,  which  portrays  old 
Uncle  Tom,  of  Harriet  Beecher  Stowe's 
play,  sitting  in  front  of  his  cabin,  smok- 
ing a  pipe,  and  thinking  of  the  days  be- 
fore and  after  the  Civil  war.  It  provides 
excellent  setting  for  old  Southern  melo- 
dies. "The  Bandelero"  is  the  story  of  a 
party  of  tourists,  in  the  Pyrenees,  which 
meet  with  a  bandelero,  a  bandit,  who 
holds  them  up,  and  very  accommodat- 
ingly sings  old  French  tunes  for  them. 

Practically  every  fan  on  Chicago's 
south  side  sets  a  certain  number  of  hours 
apart  each  night  to  listen  to  WMBB,  for 
its  entertainment  is  so  excellent  that  the 
desire  to  tune  in  for  distance  fades  away. 


Long-Range  Reception  in 
Daytime  Succeeds 

(Continued  from  page  24) 
particularly  above  300  meters,  has  much 
less    range    than    the    extremely  low  or 
short  wave   circuit   during  the   daylight 
hours. 

"The  Expedition  carries  a  full  com- 
pliment of  the  newly  developed  Zenith- 
Reinartz  short  wave  apparatus  to  equip 
all  three  planes  and  both  the  Bowdoin 
and  Peary,  but  the  high  power  low  fre- 
quency sets  will  also  be  installed,  thereby 
doubly  protecting  the  safety  of  the  men, 
and  insuring  constant  communication 
with  the  outside  world. 

"Commander  MacMillan  did  not  re- 
fuse to  install  the  Navy  radio  apparatus, 
nor  did  Secretary  Wilbur  intend  that  the 
short  wave  apparatus  be  taken  off. 
Recalling  Commander  Byrd's  telegram 
to  Secretary  Wilbur,  the  Navy  apparatus 
did  not  arrive  in  Boston  in  time  to  take 
on  board  the  S.  S.  Peary,  and  although 
Secretary  Wilbur  was  of  the  impression 
that  his  communications  were  not  given 
attention,  it  later  developed  and  as  was 
further  shown  by  Commander  Byrd's 
telegram,  not  only  were  the  Secretary's 
wires  received,  but  they  were  answered 
by  Byrd  although  they  evidently  did 
not  reach  the  Secretary's  office.  How- 
ever, as  soon  as  wires  at  both  ends  did 
connect,  MacMillan  immediately  issued 
orders  to  stand  by  and  await  the  arrival 
of  the  Navy  apparatus,  and  out  of  this 
situation  many  erroneous  reports  ap- 
peared in  print  throughout  the  entire 
country. 

"With  both  types  of  circuits  on  board, 
Commander  McDonald's  facilities  pre- 
sent even  greater  opportunity  in  his 
radio  research  and  experimental  work, 
aside  from  doubly  insuring  the  safety 
of  all  men  in  the  MacMillan   Party." 


Order  your  August  RADIO  AGE  now  if 
you  couldn't  get  one;  last  month!  —  50c 
postpaid  from  RADIO  AGE,  Inc. 


RADIO  AGE  for  September,  1925 


Radio  Breaks  Down  Rural 
Isolation 

(Continued  from  page  27) 
covers  the  athletic  activities  of  the  col- 
lege.      On     Sunday    during    the    school 
year  the  chapel  serviceis  sent  out  and  the 
daily  schedule  includes  the  chimes. 

D.  C.  Faber,  director  of  the  Engineer- 
ing Extension  department  and  in  charge 
of  the  radio  short  courses,  and  H.  B. 
Deal,  instructor  of  electrical  engineering, 
have  been  active  in  directing  the  work 
of  Station  YVOI.  Prof.  Faber  is  a  mem- 
ber of  the  program  committee  as  is  Mr. 
Deal,  who  is  also  engineer  for  YVOI.  The 
other  members  of  the  committee  include 
Prof.  R.  K.  Bliss,  chairman,  who  is 
director  of  the  Agricultural  Extension 
Department;  Prof.  F.  A.  Fish,  technical 
director  and  also  of  the  Engineering 
Department;  Prof.  Tolbert  McRae, 
Music  Department;  Charles  Roach,  pro- 
gram director  and  Blair  Converse,  Pub- 
licity director. 

Prof.  Faber,  in  discussing  the  problems 
confronting  the  sponsors  of  WOI,  pointed 
out  that  of  first  importance  was  the 
matter  of  "making  WOI  serviceable  to 
the  farmers  so  that  they  will  derive  all 
that  the  Iowa  State  College  may  have 
to  offer  to  aid  and  assist  them  in  their 
work." 

Short  Wave  Training 
'  1 1HE  radio  short  course  which  is  open 
-*-  to  amateurs  has  been  offered  at  the 
college  for  four  years.  A  veritable  army 
of  program  listeners  and  amateurs  who 
revel  in  wireless  receiving  and  sending 
swept  down  upon  the  campus  four  years 
ago  when  the  course  was  first  offered. 
More  than  500  were  in  attendance. 

At  the  several  courses  presented  many 
exhibits  have  been  provided,  and  there 
have  been  technical  talks,  a  series  of 
round  table  discussions  and  an  open 
forum  for  the  manufacturers'  repre- 
sentatives. Every  phase  of  radio  has 
been  offered,  the  subjects  being  handled 
from  the  standpoint  of  the  technical 
fan  as  well  as  the  enthusiast  who  spends 
his  spare  time  twisting  dials. 

Since  the  first  two-day  course  was 
started,  it  has  been  an  annual  feature  in 
April.  On  account  of  the  drop  in  attend- 
ance on  the  part  of  the  program  listeners, 
this  part  of  the  course  was  abandoned. 
The  registration  this  year  indicated 
the  presence  of  100  or  more,  aside  from 
the  35  or  40  drawn  from  the  student  body 
at  the  college. 

There  is  no  charge  for  the  course,  and 
students  from  Minnesota,  Illinois  and 
Nebraska,  as  well  as  Iowa,  have  taken 
advantage  of  the  opportunity  afforded 
to  familiarize  themselves  with  the  prob- 
lems radio  has  to  offer.  Stations  WOI 
and  9LC,  the  last  named  a  station  built 
and  maintained  by  the  students  at  Iowa 
State  College,  are  both  available  for 
inspection  at  the  time  the  short  course 
is  held,  one  of  the  features  of  the  course 
being  the  information  supplied  covering 
the  experiments  carried  on  at  these  two 
stations. 


The  Magazine  of  the  Hour 


63 


Another  I 

Pacent  Achievement* 


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64  RADIO  AGE  for  September,  1925 


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The  famous  Silver-Marshall  parts  were  used  exclu- 
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The  Magazine  of  the  Hour 

How  to  Build  a  5 -Tube 
Circloid  Coil  Set 

(Continued  from  page  54) 
to  one  of  the  tap  posts  gives  sharp  tuning 
for  city  use  or  in  the  vicinity  of  strong 
local  stations,  while  the  other  post  con- 
siderably broadens  the  tuning  where 
extreme  selectivity  is  not  desirable,  as 
in  the  open  country  or  at  great  distances 
from  the  stations. 

The  two  remaining  coils  are  of  the  two 
circuit  type,  with  independent  primaries 
and  secondaries,  and  act  as  the  first  and 
second  radio  frequency  transformers  in 
a  conventional  two  stage  radio  frequency 
circuit.  The  windings  are  so  adjusted 
that  the  coupler  and  transformer  con- 
densers "log"  perfectly  under  all  condi- 
tions, regardless  of  the  difference  in  their 
construction.  By  connecting  the  antenna 
to  the  "sharp"  post,  local  stations  are 
tuned  out  completely  within  two  or  three 
dial  divisions.  Connected  to  the  "broad 
post,"  local  comes  in  and  out  within  five 
to  eight  dial  divisions,  depending  upon 
the  strength  and  location  of  the  station. 

This  may  sound  simple  and  of  no 
particular  consequence,  but  if  you  expect 
to  use  the  set  both  in  the  city  and  in  the 
country  you  will  find  that  the  tapped 
coupler  is  of  the  greatest  convenience  and 
assistance  in  obtaining  the  desired  degree 
of  selectivity  and  sharpness.  If  the  set 
tunes  very  sharp,  it  will  enable  you  to 
get  through  local  traffic,  but  at  a  con- 
siderable distance  from  the  stations  this 
will  make  it  very  difficult  to  pick  up  weak 
signals.  In  fact,  with  a  very  sharp  set, 
you  may  skip  over  half  a  dozen  stations 
without  being  aware  of  their  existence 
at  all.  Broadening  the  tuning  to  twice 
the  number  of  dial  divisions  or  more 
gives  you  more  leeway  in  the  adjustments. 

Suitable  Hook-Ups 

With  the  receiver  assembled  as  shown, 
any  five  tube  hook-up  can  be  adopted, 
either  of  the  radio-frequency  type  or 
reflex.  I  have  worked  it  as  a  simple 
straight-line  radio  frequency  circuit,  as  a 
radio  frequency  "Bridge"  circuit  and  as 
a  reflex  with  excellent  results  in  all  cases. 
Any  five  tube  circuit  shown  in  RADIO 
AGE  to  date  can  be  used  with  great 
success  with  these  self-contained  field 
coils,  much  better  results  being  obtained 
as  a  rule  than  with  the  solenoid  coils 
originally  recommended,  for  with  the 
circloids  we  do  not  have  to  combat  self- 
oscillations  and  the  howling  due  to  exces- 
sive regeneration.  The  selectivity  is 
much  improved  because  the  coils  cannot 
act  as  aerials  within  themselves  and  thus 
cannot  pick  up  interferences  that  are 
usually  out  of  control  with  solenoids. 

Wiring  the  Receiver 

For  wiring  the  receiver  outlined  above, 
you  will  find  that  rubber  covered  flexible 
wire  is  far  preferable  to  the  ordinary 
soldered  bus-bar  wiring.  Very  small 
rubber  covered  strand  is  cut  to  length 
and  then  is  provided  with  connection 
lugs  or  eyes  at  either  end,  which  are 
clamped  down  firmly  over  the  ends  by 
means  of  your  pliers.  The  eyes  are  then 
screwed  under  the  binding  screws  of  the 
apparatus  and  the  wiring  is  completed 
without  the  use  of  a  soldering  copper  and 
without  the  troubles  that  generally 
attend  amateur  soldering.  It  is  not 
necessary  to  spend  so  much  time  and 
thought  in  arranging  the  runs  of  the 
flexible  wiring,  as  with  bus-bar  for  the 
rubber  insulation  affords  perfect  protec- 
tion at  all  points  and  makes  it  possible 
to  run  straight  between  the  two  connec- 
tion'points  instead  of  running  all  around 
the  lot  as  is  common  with  bus  wiring. 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


65 


A  Radio  Veteran  Does  Some 
Reminiscing 

(Continued  from  page  31) 
and  velvet  hangings.     Also,  the  set  they 
procured  was  just  about   four   times    as 
powerful  as  ours. 

It  didn't  take  long  for  the  news  to 
get  about  that  the  other  afternoon  paper 
had  the  better  broadcasting  set.  It  was 
then  that  the  real  fight  for  talent  com- 
menced. 

In  just  one  way  were  we  superior  to 
the  other  station.  We  provided  taxi- 
cab  transportation  for  our  artists  whereas 
the  other  station  allowed  them  to  get  to 
the  studio  the  best  way  they  could. 
Even  this  slight  edge  proved  our  downfall 
in  one  instance. 

As  I  remember  it,  the  only  person  1 
had  been  able  to  book  for  this  particular 
evening  was  a  woman  who  had  promised 
to  sing  several  numbers,  interspersed 
with  selections  on  the  phonograph  and 
the  reproducing  piano.  I  was,  of  course, 
to  send  a  cab  for  her.  I  was  so  desperate 
that  I  would  have  sent  a  brass  band  along 
as  escort  had  she  demanded  it  and  had  I 
been  able  to  obtain  it. 

I  telephoned  the  cab  company  and 
gave  them  the  name,  address  and  time 
of  appearance  of  our  lone  entertainer. 
Then  I  went  to  the  station,  content  that, 
for  that  evening  at  least,  I  was  fixed 
for  a  program. 

The  singer  was  due  to  go  on  at  7:40 
o'clock.  We  opened  the  program  at 
7:15  o'clock  with  baseball  scores,  news 
items  and  selections  on  the  reproducing 
piano  and  the  phonograph.  Along  about 
7:25  we  began  to  look  for  our  artist. 
The  cab  company  usually  got  our  enter- 
tainers to  the  station  10  or  15  minutes 
before  they  were  due  to  appear. 

Seven-thirty  and  no  singer  had 
arrived.  Percy  began  to  get  worried 
and  every  time  he  shifted  the  piano  or 
phonograph  in  front  of  the  horn  he 
wanted  to  know  where  the  singer  was. 
By  7:35  I  was  worried  and  peevish  myself 
and  I  snapped  back  that  I  wasn't  any 
mind-reader  and  how  should  I  know 
where  she  was? 

Seven-forty  and  still  no  singer.  Percy 
was  downright  belligerent.  He  was 
getting  tired  of  shifting  the  piano  and 
the  phonograph.  In  our  sweetest  voice 
we  informed  the  listeners  that  our  artist 
had  been  delayed  but  that  she  had  tele- 
phoned that  she  was  on  the  way. 

Seven-forty-five  came  and  passed. 
Seven-fifty.  Percy  was  ready  to  anni- 
hilate me,  the  station  and  the  entire 
building.  During  one  of  the  piano  num- 
bers he  viciously  picked  up  the  head 
phones  and  tuned  in  on  our  sister  station. 
The  expression  of  his  face  changed.  His 
eyes  grew  wild.  Hastily  he  clapped  the 
head  phones  over  my  ears. 

In  stentorian  tones  the  young  man 
at  the  other  station  was  announcing  the 
fact  that  Miss  So-and-So  had  unex- 
pectedly dropped  into  the  station  and 
that  now  the  fans  would  have  the  pleasure 
of  hearing  her  in  a  group  of  songs.  The 
Miss  So-and-So  was  our  artist! 

Of  course  the  explanation  was  simple. 
A   new  cab   driver   had    been   given   the 
(Turn  to  page  69) 


A  Good  Tube 

for  a  good  Set' 


Your  dealer  aetle   Maonotrons  in 

the  type  SOl-A.  199  and  199larae 

base.      $2.50  all   types. 


A  GLASS,  a  base  and 
some  hunks  of  wire 
— Kipling  would  have  said 
about  vacuum  tubes.  And 
so  they  are.  But  what  a 
difference  the  method  of 
assembly  and  manufac- 
ture   makes! 


MAGNATRONSarebuilt 
with  the  precision  of  a  fine 
watch,  and  tested  just  as 
carefully  before  they  leave 
the  factory.  You  can  al- 
ways count  on  MAGNA- 
TRONS  to  get  the  most 
and  best  out  of  your  set. 


Connewey   Electric   Laboratories, 
Magnatron  Building,   Hoboken,   N.  J. 


Diagrams  for  Intermediate 
Transformers 

In  the  August  RADIO  AGE,  on  page 
89,  was  printed  a  description  of  the  con- 
struction of  the  ideal  intermediate  fre- 
quency transformer.  For  the  benefit  of 
readers  desiring  pictorial  explanations,  we 
are  printing  Figures  1,  2  and  3  to 
illustrate  the  description  further. 


Looking  at  the  curves  of  Figure  1,  we 
see  A,  B,  C  and  D.  "A"  represents  the 
ideal  transformer,  giving  infinite  amplifi- 
cation over  a  10,000  cycle  band,  yet  at 
no  other  frequencies.  "B"  is  an  air-core 
transformer  giving  the  highest  possible 
amplification.  It  is  useless,  since  it  will 
not  pass  music  and  speech,  and  is  subject 
to  the  physical  limitations  previously  set 
forth.  "C"  is  the  practical  ideal  trans- 
former, passing  the  desired  frequency 
band  with  a  gain  variation  insufficient  to 
cause  distortion,  yet  with  a  limited  field 
and  good  stability.  "D"  is  the  extreme 
for  perfect  reproduction — but  gives  no  se- 
lectivity and  no  amplification  to  speak  of. 

Suppose  we  wish  to  construct  "C", 
which  is  the  best  transformer  we  can 
build  practically.  We  will  require  a 
bobbin  turned  out  of  wood  or  built  up 
of  fibre,  together  with  two  pieces  of  core 
iron  as  shown  in  Figure  2.  This  bobbin 
■     Tested  and  Approved  by  RADIO  AGE 


is  wound  with  1,400  turns  of  No.  36  SSE 
in  the  smaller  slot  for  the  primary,  and 
3300  turns  of  the  same  wire  in  the  larger 
slot  for  the  secondary.  The  core  is  put 
in  so  that  the  air  gap  comes  under  the 
larger  or  secondary  coil,  and  the  ends  of 
the  laminations  are  bent  over  each  other 
to  hold  them  together.  This  transformer 
may  be  placed  in  a  small  metal  can,  with 
leads  brought  out  as  desired.  It  should 
first  be  boiled  in  a  resin-bees-wax  com- 
pound, with  which  the  can  should  be  filled. 
This  transformer,  while  selective,  may 
best  be  used  in  conjunction  with  another 
type,  which  would  be  a  compromise 
hetween  "B"  and  "C". 


OLD 

Inn 


~T 


ira 


INTERMEDIRTE  TRM5F0RMER. 

PRiMftffy    ut-oo  TURNS 
"36  SSE      WIRE 
IHSIOC-'B",  OUTSIDE-  "PLRTE" 
SECONOfiRi      J300   TUffHS 
'36  SSE  W/ff£ 
IHSIDE'P",  OUTSIDE-  "61(10" 


CORE  O07'  SILICON  STEEL 
1  PIECE  /IS  SHOWN  J  PIECE 
WITHOUT  CENTER  PPOJECTini. 
tylOUNT  WITH  PROJECTION 

under'  primhrv  coil 
impregnate   in   kosin- 
beeswa.x  compound. 


FILTER. 

PRIMARY:   ZSO   TURNS 
"36  DSC    WIRE 
INSIDE  -B"     OUTSIDE  -"PLATE:" 
SECONDARY    ISOO  TURNS 
'36  DSC    WIRE 
INSIDE-'/!"  ,  OUTSIDE-'&RIO" 
IMPREGNATE  IN  ROSIH-BEEWI* 
COMPOUND. 


66 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA      Westinghouse  Electric  &  Mfg.  Co East  Pittsburgh,  Pa.     309         KFVO 

KDLR       Hadio  Electric  Co Devils  Lake,  N.  D.     231  KFVR 

KDPM      Westinghouse  Electric  &  Mfg.  Co Cleveland,  Ohio     270  KFVS 

KDYL       Newhouse  Hotel Salt  Lake  City,  Utah     250  KFVY 

KDZB        Frank  E.  Siefert Bakersfield.  Calif.     240  KFVZ 

KDZI         Electric  Supply  Co : Wenatchee,  Wash.     360  KFWA 

KFAB       NebraskaBuickAutoCo. ,13th  &  Que  St3 Lincoln,  Nebr.     341  KFWB 

KFAD        McArthur  Bros.   Mercantile  Co Phoenix,  Ariz.     273  K.FWD 

KFAE        State     College  of    Washington Pullman,  Wash.  348  KFWF 

KFAF        Western   Radio  Corporation Denver,  Colo.  278  KFWH 

KFAJ        University  of  Colorado Boulder,  Colo.     360  KFWI 

KFAN       University  of  Idaho Moscow.  Idaho  230  KFWM 

KFAU       Boise  High  School Boise,  Idaho  271  KFWO 

KFAW      The  Radio  Den  (W.  B.  Ashford) Santa  Ana,  Calif.  280  KFWP 

KFBB       F.  A.  Buttrey  &  Co Havre.  Mont.  360  KGB 

KFBC        W.  K.Azbill San  Diego,  Calif.  278  KGO 

KFbG       First  Presbyterian  Church Tacoma,  Wash.  250    '      KGU 

KFBK       Kimball-Upson  Co Sacramento,  Calif.  283  KG W 

KFBL        Leeso    Bros Everett.  Wash.  224  KGY 

KFCB        Nielson  Radio  Supply  Co Phoenix.  Ariz.  238  KHJ 

KFCC        The  First  Congregational  Church Helena.  Mont.  248  KHQ 

KFCF        Frank  A.  Moore Walla  Walla,  Wash.  256  KJR 

KFCZ        Omaha  Central  High  School , Omaha,  Nebr.  258  KJS 

KFDD      St.  Michael  Cathedral Boise.  Idaho  252  KLDS 

KFDH       University  of  Arizona Tucson,  Ariz.  368  KLS 

KFDJ        Oregon   Agricultural   College Corvallis,   Oreg.  254  KLX 

KFDM      Magnolia  Petroleum  Co Beaumont.  Texas  315  KLZ 

KFDX       First   Baptist   Church Shreveport,    La.  360  KMJ 

KFDY      South  Dakota  State  College Brookings,  S.  Dak.  360  KMO 

KFDZ       Harry  O.  Iverson Minneapolis,    Minn.  231  KNX 

KFEC       Meier  &  Prank  Co Portland,  Oreg.  248  KOA 

KFEK        Augsbury  Seminary Minneapolis. Minn.  261  KOB 

KFEL        Winner  Radio  Corp Denver,  Colo.  254  KOIL 

KFEQ       J.  L.  Scroggin Oak.  Nebr.  268  KOP 

KFEY       Bunker  Hill  &  Sullivan  Mining  and  Concentrating  Co Kellogg,  Idaho  233  KPO 

KFFP        First  Baptist  Church Moberly,  Mo.  260  KPPC 

KFFV        Graceland    College Lamoni.    Iowa  280  KPRC 

KFGB      Heidbreder  Radio  Supply  Co Utica.  Neb.  224  KQP 

KFGC      Louisiana  State  University Baton  Rouge.  La.  254  KQV 

KFGD       Chickasha  Radio*  Electric  Co Chickasha,  Okla.  248  KQW 

KFGH       Leland  Stanford  University Stanford  University,  Calif.  273  KRE 

KFGS        Crary    Hardware    Co Boone,    Iowa  226  KSAC 

KFHA       Western  State  College  of  Colorado Gunnison,  Colo.  252  KSD 

KFHH      Ambrose  A.  McCue Neah  Bay,  Wash.  261  KSL 

KFHL       Penn    College Oskaloosa ,    Iowa  240  KTCL 

KFI           E.  C.  Anthony.  Inc Los  Angeles,  Calif.  468  KTHS 

KFIF         Benson  Polytechnic  Institute Portland,  Oreg.  248  KTW 

KFIO         North    Central   High   School Spokane,   Wash.  252  KUO 

KFIQ        First  Methodist  Church Yakima,  Wash.  242  KUOM 

KFIU        Alaska  Electric  Light  &  Power  Co Juneau.  Alaska  226  KWG 

KFIZ         Daily  Commonwealth Fond  du  Lac,  Wis.  273  KWKC 

KFJB        Marshall   Electrical   Co Marshalltown.    Iowa  248  KWWG 

KFJC        R.  B.  Fegan  (Episcopal  Church) Junction  City.  Kansas  219  KYO 

KFJF         National  Radio  Manufacturing  Co Oklahoma  City,  Okla.  252  KYW 

KFJI         Liberty  Theatre    (E.    E.    Marsh) Astoria,  Oreg.  252  KZM 

KFJL         Hardsacg    Manufacturing   Co Ottumwa,    Iowa  242  WAAB 

KFJM       University  of  North  Dakota Grand  Forks,  N.  Dak.  280  WAAC 

KFJR       Ashley  C.  Dixon  &  Son Stevensville.  Mont.  258  WAAD 

KFJX       Iowa  State  Teacher's  College Cedar  Falls,  Iowa  280  WA AF 

KFJY       Tunwall  Radio  Co Fort  Dodge,  Iowa  246  WAAM 

KFJZ        W.E.Branch Fort  Worth.  Texas  254  WAAW 

KFKA      Colorado  State  Teachers  College Greeley,  Colo.  273  WABA 

KFKQ       Conway  Radio  Laboratories  (Ben  H.  Woodruff) Conway,  Ark.  250  WABB 

KFKU       The   University  of  Kansas Lawrence.   Kans.  275  WABC 

KFKX       Westinghouse  Klectric  &  Manufacturing  Co Hastings,  Nebr.  288  WABI 

KFLD       Paul  E.  Greenlaw Franklinton,   La.  234  WABL 

KFLP       Everett  M.  Foster Cedar  Rapids,  la.  256  WABN 

KFLR       University  of  New  Mexico Albuquerque,  New  Mexico  254  WABO 

KFLU       Rio  Grande  Radio  Supply  House San  Benito,  Texas  236  WABQ 

KFLV        Rev.  A.  T.  Frykman Rockford.  111.  229  WABR 

KFLX       George  Roy  Clough Galveston,  Texas  240  WABU 

KFLZ       Atlantic  Automobile  Co Atlantic,  la.  273  WABW 

KFMB      Christian  Churches Little  Rock.  Ark.  254  WABX 

KFMQ      University  of  Arkansas Fayetteville.  Ark.  299  WABY 

KFMR      Morningsile  College Sioux  City,  Iowa  261  WABZ 

KFMW     M.    G.    Sateren Houghton.    Mich.  266  WADC 

KFMX     Carleton    College Northfield.    Minn.  336  WAFD 

KFNF       Henry   Field   Seed   Co Shenandoah,   Iowa  266  WAHG 

KFNG      Wooten's  Radio  Shop Coldwater.  Miss.  254  WAMD 

KFNV        L.  A.  Drake  Battery  and  Radio  Supply  Shop Santa  Rosa,  Calif.  234  WBAA 

KFOA        Rhodes    Department   Store Seattle.    Wash.  454  WBAC 

K.FOL       Leslie  M.  Schafbush Marengo.  Iowa  234  WBAH 

KFON      Echophone  Radio  Shop Long  Beach.  Calif.  234  WBAK 

KFOO       Latter  Day  Saints  Univen  .ty Salt  Lake  City,  Utah  261  WBAO 

KFOP       Rohrer    Elec.    Co Marshfield,    Ore.  240  WBAP 

KFOR       David  City  Tire  &  Electric  Co David  City,  Nebraska  226  WBAV 

KFOT       College  Hill  Radio  Club Wichita,  Kansas  231  WBAX 

KFOX       Board  of  Education,  Technical  High  School Omaha,  Nebraska  248  WBAY 

KFOY       Beacon  Radio  Service St.  Paul.   Minn.  226  WBBG 

KFPG       Garretson  and  Dennis Los  Angeles.  Calif.  238  WBBL 

KFPL       C.  C.  Baxter Dublin,  Texas  242  WBBM 

KFPM      The  New  Furniture   Co Greenville.   Texas  242  WBBN 

KFPR        Los  Angeles  County  Forestry  Dept Los  Angeles.  Calif.  231  WBBP 

KFPT       Cape  &  Johnson Salt  Lake  City.  Utah  286  WBBR 

KFPW      St.  Johns  M.  E.  Church Carterville.  Mo.  268  WBBS 

KFPY       Symons    Investment    Co Spokane.    Wash.  283  WBBU 

KFQA      The   Principia St.  Louis,  Mo.  264  WBBX 

KFQB      The  Searchlight  Publishing  Co Fort  Worth,  Texas  221  WBBY 

KFQC       Kidd  Brothers  Radio  Shop Taft.  Calif.  258  WBCN 

KFQH      Radio  Service  Co Burlingame.    Calif.  231  WBDC 

KFQP       G.  S.  Carson,  Jr Iowa  City,  la.  284  WBES 

KFQT       Texas  National  Guard Dennison,  Texas  252  WBGA 

KFQU      W.  Riker Holy  City,  Calif.  253  WBOQ 

KFQW     C.   F.   Knierim North  Bend,  Wash.  248  WBR 

KFQY      Farmers  State  Bank Belden.  Neb.  273  WBRC 

KFQZ       Taft    Products    Co Hollywood.    Calif.  240  WBRE 

KFRC       City  of  Paris  Dry  Goods  Co San  Francisco,  Calif.  268  WBS 

KFRM      James  F.  Boland Fort  Sill.  Okla.  263  WBT 

KFRU      Etherical  Radio  Co Bristow,  Okla.  394  WBZ 

KFRW      United  Churches  of  Olympia Olympia,  Wash.  220  WCAD 

KFRX       J.    Gordon   Klemgard Pullman.   Wash.  217  WCAE 

KFRZ       The    Electric    Shop Harrington,    Neb.  222  WCAH 

KFSG       Angelus    Temple Los    Angeles.    Calif.  272  WCAJ 

KFSY        The    Van    Blaricon   Co Helena.Mont.  261  WCAL 

KFUJ        Hopper  Plumbing  and  Heating  Co Breckenridge.  Minn.  242  WCAO 

KFUL        Thomas  Goggan  &  Bros.  Music  Co Galveston,  Texas  258  WCAP 

KFUM     W.  D.  Pyle Colorado  Springs,  Colo.  242  WCAR 

KFUO      Concordia  Seminary - St.  Louis.  Mo.  549  WCAS 

KFUP        Fitzsimmons    General     Hospital Denver.     Colo.  234  WCAT 

KFUQ      Julius  Brunton  and  Sons  Co San  Francisco.  Calif.  234  WCAU 

KFUR       H.  W.  Peery  and  C.  Redfield Ogden.  Utah  224  WCAX 

KFUS       Louis    L.    Sherman Oakland,    Calif.  233  WCAZ 

KFUT       University  of  Utah Salt  Lake  City,  Utah  271  WCBA 

KFUU       Colburn    Radio   Labs San   Leandro.   Calif.  231  WCBC 

KFUY      Irvine  M.  Bouchard Butte,  Mont.  254  WCBD 

KFUZ        Y.   M.  C.  A Virginia.    Minn.  244  WCBE 

KFVC       Bensberg's  Music  Co Camden,  Arkansas  248  WCBF 

KFVD        McWhinnie  Electric  Co San  Pedro.  Calif.  202  WCBG 

KFVE       Film  Corporation  of  America St.  Louis.  Mo.  245  WCBH 

KFVF       Clarence  B.Juneau Hollywood.  Calif.  208  WCBM 

KFVG       First    M.    E.    Church Independence,    Kansas  236  WCBN 

KFVH       Whan  Radio  Shop  (Herbert  Whan) Manhattan,  Kansas  218  WCBQ 

KFVI         Headquarters  Troop,  56th  Calvary Houston.  Texas  248  WCBR 

KFVK       Sacramento  Chamber  of  Commerce Sacramento,  Calif.  248  WCBT 

KFVL  Lt.  Richard  F.  Lussier,  5th  Ir/f.  U.S.A.  .Vancouver,  Barracks.  Vancouver,  Wash.  231  WCBU 

KFVN        Carl  E.  Bagley ■ Welcome.  Minn.  227  WCBX 


F.  M.  Henry Kirkavilla.  Mo.  226 

Moonlight  Ranch Route  6,  Denver,  Colo.  246 

Cape  Girardeau  Battery  Station Cape  Girardeau,  Mo.  224 

Radio  Supply  Co Albuquerque,  N.  M.  250 

Glad  Tidings   Tabernacle San   Francisco,  Calif.  234 

Browning  Bros.  Co Ogden,  Utah  214 

Warner     Bros. .    .      Hollywood.     Calif.  252 

Arkansas  Light  &  Power  Co Arkadelphia,  Arkansas  266 

St.  Louis  Truth  Center St.  Louis,  Mo.  214 

F.  Wellington  Morse,  Jr Chico,  Calif.  254 

Radio  Entertainments,  Inc South  San  Francisco.'Calif .'  220 


224 


Oakland  Educational  Society Oakland '  Calif! 

Lawrence  Mott Avalon,  Calif.  211 

Rio  Grande  Radio  Supply  House Brownsville.  Texas  214 

Tacoma  Daily  Ledger. Tacoma    Wash.  252 

General  Electrio  Co Oakland,  Calif.  361 

Marion  A.   Mulrony Honolulu,   Hawaii,   Waikiki  Beach  370 

Portland  Morning  Oregonian Portland,  Oreg.  491 

St.  Martina  College  (Reb.  Sebastian  Ruth) Lacy  Wash  253 

Times-Mirror  Co LoS  Angeles'.  Calif.  405 

Louis  Wasmer  Seattle.  Wash.  273 

Northwest  Radio  Service  Co Seattle.   Wash.  384 

Bible  Institute  of  Los  Angeles.  Inc Los  Angeles,  Calif.  293 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints,  Independence   Mo.  441 

Warner  Brothers   Radio  Supplies  Co Oakland.   Calif.  242 

Tribune  Publishing  Co Oakland,    Calif.  508 

Reynolds  Radio  Co Denver,  Colo.  283 

San  Joaquin  Light  &  Power  Corp Fresno,  Calif.  243 

Love  Electric  Co » Tacoma,  Wash.'  250 

Los  Angeles  Evening  Express Los  Angeles,  Calif.  337 

General  Electric  Co Denver,  Colo.  323 

New  Mexico  College  of  Agriculture  &  Mechanic  Arts,  State  College.  N.Mex.  348 

Monarch  Manufacturing  Co Council  Bluffs,  Iowa  278 

Detroit  Police  Department Detroit    Mich.  286 

Hale    Bros .San    Francisco,'    Calif.  428 

Pasadena    Presbyterian    Church Pasadena,  Calif.  229 

Houston  Post-Dispatch Houston,  Texas  270 

Apple  City,  Radio  Club Hood  River,  Oregon  270 

Doubleday-Hill    Electrio    Co Pittsburgh      Pa  270 

SH,rls„D-    HerTold '.'.    San  Jose.  Calif'.  226 

V.  C.  Battery  &  Electric  Co Berkeley,  Calif.  275 

Kansas  State  Agricultural  College Manhattan,   Kan 


341 

. ...  St.  Louis,  Mo.    545 


Post  Dispatch  (Pulitzer  Pub.  Co.). 

Radio  Sendee  Corp.  of  Utah Salt  Lake  CiTyVUtah 

American  Radio  Telephone  Co..  Inc Seattle.  Wash.  306 

New  Arlington  Hotel  Co Hot  Springs.  Ark.  375 

First  Presbyterian  Church Seattle,  Wash.  455 

Examiner    Printing    Co San    Francisco,    Calif.  246 

State  University  of  Montana Missoula,  Montana  244 

Portable  Wireless  Telephone  Co Stockton,  Calif.  248 

Wilson    Duncan    Studios Kansas    City,    Mo.  236 

City  of  Brownsville Brownsville,   Texas  278 

Electric  Shop Honolulu,  Hawaii  270 

Westinghouse  Electrio  &  Mfg.  Co Chicago  111.  535 

Preston    D.   Allen Oakland,    Calif.  242 

Valdemar  Jensen New  Orleans,   La.  263 

Tulane    University New    Orleans,  La.  275 

Ohio  Mechanics  Institute Cincinnati.  Ohio  248 

Chicago  Daily  Drovers  Journal Chicago    111.  286 

I.  R.    Nelson  Co Newark.  N.J.  263 

Omaha  Gram  Exchange Omaha,  Nebr.  285 

Lake  Forest  University Lake  Forest,  111.  227 

Harrisburg   Sporting    Goods    Co Harrisburg,    Pa.  266 

Asheville  Battery  Co..  Inc Asheville,  N.  C.  254 

Bangor  Railway  &  Electric  Co Bangor.  Me.  240 

Connecticut    Agricultural    College Sorrs.    Conn.  283 

Ott  Radio.  Inc LaCrosse,  Wis.  244 

Lake  Avenue  Baptist  Church Rochester,  N.  Y.  283 

Haverford  College,   Radio  Club .  .Haverford,  Pa.  0261 

Scott  High  School,  N.  W.  B.  Foley Toledo,  Ohio  270 

Victor  Talking  Machine  Co Camden,  N.  J.  224 

College  of  Wooster Wooster,  Ohio  234 

Henry  B.  Joy Mt.  Clemens.  Mich.  270 

John    Magaldi.    Jr Philadelphia.    Pa.  242 

Coliseum  Place  Baptist  Church New  Orleans,  La.  263 

Allen  T.  Simmons  (Allen  Theatre) Akron.  Ohio  258 

Albert  B.  Parfet  Co Port  Huron,  Mich.  233 

A.  H.  Grebe  &  Co Richmond  nill,  N.  Y.  315 

Hubbard  &  Co Minneapolis.  Minn.  244 

Purdue  University W  .  Lafayette.  Ind .  283 

Clemso     Agric.  College Clemson  College.  S.  C.  331 

The  Dayton  Co Minneapolis,  Minn.  417 

Pennsylvania    State    Police Harrisburg.    Pa.  275 

James  Milhkan  University Decatur,     111.  360 

Wortham-Carter  Publishing  Co.  (Star  Telegram) Fort  Worth,  Texas  476 

Erner    &   Hopkins    Co Columbus,   Ohio  292 

John  H.  Stenger,  Jr Wilkes-Barre,   Pa.  254 

Western  Electric  Co New  York,  N.  Y.  492 

Irving    Vermilya Mattapoisett.     Mass.  248 

Grace    Covenant    Presbyterian    Church Richmond,    Va.  253 

Atlass    Investment    Co Chicago,    111.  226 

Blake,  A.  B Wilmington,  N.  C.  275 

Petoskey    High    School Petoskey,    Mich.  246 

Peoples  Pulpit  Asso Rossville,  N.  Y.  273 

First  Baptist  Church New  Orleans.  La.  252 

Jenks  Motor  Sales   Co Monmouth.   111.  224 

Ruffner  Junior   High   School Norfolk,   Va.  222 

Washington    Light  Infantry  Co.    "B"    118th   Inf Charleston,   S.   C.  268 

Foster     &     McDoland Chicago,     111.  266 

Baxter  Laundry  Co Grand  Rapids,  Mich.  256 

Bliss  Electrical  School Takoma   Park.    Md.  222 

Jones  Elec.  &  Radio  Mfg.  Co Baltimore,  Md.  254 

A.  H.  Grebe   &  Co.,  Inc Richmond  Hill,  N.  Y.  236 

Pennsylvania   State   Police Butler,  Pa.  286 

Bell   Radio   Corporation Birmingham,   Ala.  248 

Baltimore  Radio  Exchange Wilkes-Barre.  Pa.  231 

D.  W.  May,  Inc Newark,  N.J.  252 

Southern    Radio  Corp Charlotte.    N.    C.  275 

Westinghouse  Electric  &  Mfg.  Co Springfield,  Mass.  333 

St.  Lawrence  University Canton,  N.  Y.  280 

Kaufmann  &  Baer  Co.  and  The  Pittsburgh  Press Pittsburgh.  Pa.  461 

Entrekin  Electrio  Co Columbus.  Ohio  286 

Nebraska  V\  esleyan  University University  Place,  Nebr.  283 

St.   Olaf  College Northfield,   Minn.  336 

Sanders  &  Stayman  Co Baltimore,    Md.  275 

Chesapeake  &  Potomac  Telephone  Co Washington.  D.  C.  468 


State  College  of  Mines Rapid  City.  S.  Dak.     240 


Durham  &   Co .Philadelphi  . 

LTniversity    of    Vermont Burlington, 

Carthage  College Carthage 


Cha 


111. 


278 
250 
246 


i  W.Heibachm Allentown,  Pa.     230 


rsity  of  Michigan Ann  Arbor,  Mich. 

Wilbur   C.    Voliva Zion.   111.  344 

Uhalt  Radio  Co New  Orleans,  La.  263 

Paul   J.    Miller Pittsburgh.    Pa.  236 

Howard    S.    Williams    (Portable) Pascagoula,    Miss.  268 

University   of   Miss Oxford,    Miss.  242 

Charles  Swarz Baltimore,  Md.  229 

James    P.    Boland Ft.    Beni.    Harrison,    Ind.  266 

First     Baptist    Church Nashville,    Term.  236 

C.   H.   Messter Providence,  R.  I.  246 

Clark  University,  Collegiate  Dept Worcester,  Mass.  238 

Arnold  Wireless  Supply  Co Arnold,  Pa.  254 

Radio  Shop  of  Newark  (Herman  Lubinsky) Newark,  N.  J.  233 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


67 


"THE  TUBE  WITH  A  PEDIGREE" 


tfyHERE  is  only  one  way  to  measure  the 
value  of  a  radio  tube,  regardless  of  who 
made  it,  and  that  is  by  the  characteristic 
curve  reading.  In  this  way,  and  no  other, 
can  its  value  as  a  tube  be  determined  in 
advance.  All  MUSSELMAM  TUBES 
have  a  characteristic  curve  slip  inclosed 
at  the  factory  and  certified  when  the  read- 
ings are  above  the  standard  set  by  leading 
radio  engineers  as  to  what  constitutes  an 
unusually  good  tube. 


* 


Jobbers,  manufacturers,  and 
dealers  are  invited  to  write  for 
details  as  to  sales  franchise. 


Manufactured  by 

TheVanHorne  Co.,  Franklin, Ohio 

SALES  OFFICE 

A.  J.  MUSSELMAN 

601-C  Machinery  Hall  CHICAGO 


^Laboratory 


mr 


foe  Distortionless  JfoipiifitcatiOft 

12,000,    48,000,    50,000,     100.000  Oh  ma.     List 
S1.50  each.     Special  sizes  to  Order  S2.50  each. 

Dealers,  write  for  discounts.      When  Better  Resistances 

are  made  they  will  be  Crescents. 

Crescent  Radio  Supply  Co..  5  Liberty  St..  Jamaica.  NY. 


Appearance    and    Correctness 
in  B-T  Control 

An  effort  to  combine  a  pleasing  and  at- 
tractive appearance  with  mechanical  cor- 
rectness and  tuning  efficiency  is  evident 
in  the  new  B-T  "Better  Tuning"  Con- 
trol. 

By  the  use  of  a  unique  mechanical  ar- 
rangement, backlash  is  entirely  elimi- 
nated. The  action  is  smooth  and  even, 
and  loggings  cannot  be  "thrown  off"  by 
slipping  of  the  mechanism. 

•  Dial  numbers  are  read  from  a  scale 
passing  under  a  window  at  the  top  of  the 
instrument.  The  use  of  a  special  vernier 
device  provides  accurate  readings  to 
fractions  of  a  degree,  if  desired.  Dial 
graduations  read  0  to  100  over  180°  on 
one  side  and  100  to  0  on  the  other.  This 
feature  protects  the  purchaser  who 
might  wish  to  change  from  right  hand 
to  left  hand  condensers,  or  vice  versa. 

The  large  rotating  pointer  indicates 
wavelength  readings,  and  the  scale  is 
calibrated  for  straight-line-wavelength 
changes  in  accordance  with  present 
broadcast  station  assignments.  If  desired 
the  wavelength  plate  may  be  reversed 
for  recording  station  call  letters.  The 
user  is  thus  able  to  choose  just  about 
whatever  combination  or  style  of  reading 
or  logging  he  may  desire. 

Mounting  is  made  by  a  single  5/32  in. 
hole  through  the  panel.  All  pull  or  side 
strain  on  the  condenser  shaft  is  elimi- 
nated, as  well  as  wear  and  tear  on  con- 
denser bearings  which  might  '  impair 
alignment,  cause  short  circuits  or  destroy 
logging  records  by  changing  capacity. 


The  Famous  Truly  Portable 

Telmaco  P'l  Receiver 

Four  Tubes  Do  the  Work  of  Seven 

The  peer  of  portables  in  Bize,  weight,  ease  of  tuning, 
selectivity,  distance,  volume,  workmanship  and  price. 
Aerial,  loud  speaker  and  batteries  self  contained. 
Complete  with  tubes  and  batteries,  JIOC  An 
$143.50.    Receiver  only      ....     ^*'»»-   " 

P- 1  Kit  Saves  Too  Money  t 
Our  offer  of  the  Telmaco  P-l  Receiver  In  kit  form  has 
met   with  enthusiastic  reception.  This  contains  all 
parts,  as  built  by  us,  including  case,  drilled  and  en- 
graved panel,  and  illustrated  instructions.  CO  f|  00 

Complete  kit *OV.""* 

Ask  your  dealer  or  write  us.  Descriptive  folder  free. 


%adio  1Dr> 

Telephone  MaintenanceCo. 

20  So.  'Wells  St.    Dept.  C  Chicago,  HI. 


Stualily  %adio  Exclusively    «&    established  1918 


CONDENSER 


PHENIX  RADIO  CORP.,  1 16-F  East  25  St.,  N.Y.C. 


The  Great 

Manufacturers' 

Exposition 

Attended  by 
Leading 

Jobbers  and 
Dealers 


T&e  Official 

RADIO 


NE 


^-^  RMAShow 

'T&Efy  second 

FAIR 


NEW  YORK  OFFICES 
>i0O  TIMES  BLOG. 
NEW  YORK  CITY 


U.  J.  HERRMANN,  MANAGING  DIRECTOR 

SEPTEMBER  14*  to  19* 

MONDAY  NOON  TO  SATURDAY  MIDNIGHT 

ENTIRE  EXHIBITION   ON   GROUND   FLOOR 

IN  THE  LARGEST  HALL   IN  THE  WORLD 

258^  Field  Artillery  Armory 


68 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


WCCO      Washburn-Crosby  Co Twin  Cities,   Minn. 

WCEE       Charles  E.  Erbstein.  Villa  Olivia near  Elgin,  111. 

WCLS       H.     M.    Couch Joliet.     111. 

WCSH       Henry  P.  Rines Portland,  Maine 

WCTS      C.   T.  Scherer  Co Worcester,   Mass. 

WCX         Free  Press Detroit,  Mich. 

WDAE      Tampa    Daily    Times Tampa,     Fla. 

WDAF      Kansas  City  Star Kansas  City,   Mo. 

WDAG     J.    Laurence  Martin Amarillo,   Texas 

WDAH      Trinity   Methodist  Church   (South) El  Paso,   Texas 

WDAR      Lit     Brothers Philadelphia,      Pa. 

WDA Y      Radio  Equipment  Corp Fargo,  N.  Dak. 

WDBA      Fred  Ray Columbus,  Ga. 

WDBB      A.  H.  Waite  &  Co.,  Inc Taunton.  Mass. 

WDBC       Kirk,    Johnson    &    Co Lancaster,    Pa. 

VVDBD      Herman    Edwin    Burns Martinsburg,    W.    Va. 

WDBE      Gilham-Schoen    Elec.    Co Atlantic.    Ga. 

WDBJ       Richardson    Wayland  Electric  Corp Roanoke,  Va. 

WDBK      M.   F.   Broz Cleveland.   Ohio 

WDBL      Wis.  Dept.    of    Markets Stevens  Point,  Wis. 

WDBN      Electric    Light    &    Power    Co Bangor.    Me. 

WDBO      Rollins   College.    Inc Winter   Park,    Fla. 

WDBQ     Morton  Radio  Supply  Co Salem,  N.  J. 

WDBR      Tremont  Temple  Baptist  Church Boston.  Mass 

WDBV       The  Strand  Theatre Fort  Wayne,   Ind. 

WDBX      Otto  Baur New  York,  N.  Y. 

WDBY      North     Shore     Congregational     Church Chicago.     111. 

WDBZ       Boy  Scouts.  City  Hall Kingstown.  N.  Y. 

WDOD      Chattanooga    Radio    Co.,    Inc Chattanooga,    Tenn. 

WDWF     Dutee  Wilcox  Flint.  Inc Cranston.  R.   I. 

WDZ         J.     L.    Bush Tuscola,    111. 

WEAA       F.     D.     Fallain Flint,     Mich. 

WEAF       American  Telephone  &  Telegraph   Co New  York,  N.  Y. 

WEAH      Hotel    Lassen Wichita,    Kans. 

WEAI        Cornell    University Ithaca,    N.    Y. 

WEAJ        University   of  South    Dakota Vermilion,    S.    Dak. 

WEAM  Borough  of  North  Plainfield  (W.  Gi'-son  Buttfield) .  .  North  Plainfield.  N.  J. 

WEAN      Shenard  Co Providence,  R.I. 

WEAO      Ohio    State    University Columbus,    Ohio 

WEAR      Goodyear  Tire  and  Rubber  Co Cleveland,  Ohio 

WEAU      Davidson  Bros.  Co Sioux  City,  Iowa 

WEAY      Iris  Theatre  (Will  Horowitz,  Jr.) Houston.  Texas 

WEB         Benwood  Co St.  Louis,  Mo. 

WEBA       Electric    Shop '. Highland    Park.    N.    J. 

WEBC      Walter     Cecil     Bridges : Superior.     Wis. 

WEBD       Electrical    Equipment   and    Service   Co Anderson,   Ind. 

WEBE       Roy   W.    Walker Cambridge,    Ohio 

WEBH       Edgewater  Beach   Hotel.  Chicago  Evening   Po  ;t  Station Chicago,   111. 

WEBJ       Third  Avenue  Railway  Co New  York,  N.  Y. 

WEBK      Grand  Rapids  Radio  Co Grand  Rapids.  Mich. 

WEBM      Radio   Corporation   of   America Portable 

WEBP       E.  B.  Pedicord New  Orleans.  La. 

WEBT       The   Dayton  Coop.   Industrial  High  School Dayton.  Ohio 

WEBW     Beloit     College Beloit.    Wis. 

WEEI         The  Edison  Elect  ric  Illuminating  Co Boston.  Mass. 

WEHS      Robert    E.     Hughes Evanston,     111. 

WEMC      ' Barrien     Springs,     Mich. 

WENR      Ail-American  Radio  Corporation Chicago.  Illinois 

WEW        St.    Louis    University St.    Louis.    Mo. 

WFAA       Dallas  News  &   Dallas  Journal Dallas.  Tex. 

WFAM     Times   Publishing  Co St.  Cloud.    Minn. 

WFAV  University  of  Nebraska,  Department  of  Electric.il  Engineering.  Lincoln,  Nebr. 

WFBC      First    Baptist    Church : Knoxville.    Tenn. 

WFBD      Gethsemane  Baptist  Church Philadelphia,   Pa. 

WFBE       Van  De  Walle  Mu.ic  and  Radio  Co Seymour.    Ind. 

WFBG      The  Wm.  F.  Cable  Co Altoona,   Pa. 

WFBH      Concourse  Radio  Corporation New  York,  N.  Y. 

WFBJ       St.  John's  University Collegeville.  Minn. 

WFBQ      Wynne  Radio  Co Raleigh.  N.  C. 

WFBR       Fifth  Inf.  Mil.  Nafl  Guard.  5th  Reg.  Armory Baltimore.  Md. 

W  FBW     Ainsworth-Gates  Radio  Co Cincinnati.  Ohio 

WFBZ       Knox  College Galesburg,  111. 

WFI  Strawbridee  and  Clothier Philadelphia,  Pa. 

WFKB      Francis  K.  Bridgman Chicago.  111. 

WFUV       G.  Pearson  Ward Springfield.  Mo. 

WFUW     Earl   William   Lewis Moberly.   Mo. 

WGAL      Lancaster  Electric  Supply  &  Construction  Co Lancaster,  Pa. 

WGAQ     Youree  Hotel Shreveport.  La. 

WGAZ      South  Bend  Tribune South  Bend.  Ind. 

WGBB      Harry  H.  Carman.  217  Bedell  St Freeport,  N.  Y. 

WGBC      First  Baptist  Church Memphis.  Tenn. 

WGBF      Fink  Furniture  Co Evansville,  Ind. 

WGBG     Brietenbach's  Radio  Shop Thrifton,  Va. 

yGBI        Frank  S.  Megargee Scranton,  Pa. 

V/GBK      Lawrence  Campbell Johnstown,  Pa. 

WGBM     Theodore  N.  Saaty Providence.  R.  I. 

WGBL      Elyria  Radio  Asso.  (Albert  H.Ernst) :  .Elyria.  Ohio 

WGBQ     Stout  Institute Menominee.  Wis. 

WGBR      Marshfield    Broadcasting   Assn Marshfield,  Wis. 

WGBS       Gimbel  Brothers New  York.  N.  Y. 

WGBT      Furman   University Greenville.  S.   C. 

WGBX     University  of  Maine Orono.  Mo. 

WGBY     ProEre.-K  Sales  Co R.  R.  No. 

WGES      Coyne  Electrical  School Oak  Park.  HI. 

WGI  American  R.  &  R.  Co Meiford  Hillside,  Mass. 

WGMU    A.  H.  Grebe  &  Co.,  Inc.. Portable Richmond  Hill.  N.  Y. 

WGN         The    Tribune Chicago.  111. 

WGR         Federal  T.  and  T.  Co Buffalo,  N.  Y. 

WGY        General  Elec.  Co Schenectady.  N.  Y. 

WHA         University  of  Wisconsin Madison,  Wis. 

WHAD      Marquette  University  and  Milwaukee  Journal Milwaukee,  Wis. 

WHAG      University  of  Cincinnati Cincinnati.  Ohio 

WHAH      Hafer  Supply  Co Joplin.  Mo. 

WHAM     Unive-s.ty  of  Rochester  (Eastman  School  of  Music). Rochester,  N.  Y. 

WHAP       H.  Alvin  Simmons.  290  Flathush  Ave Brooklyn,  N.  Y. 

WHAR      Seaside   House Atlantic   City.   N.   J. 

WHAS       Courier-Journal  &   Louisville  Times Louisville.   Ky. 

WHAT      Dr.  George  W.  Young Minneapolis,  Minn. 

WHAV      Wilmington  Electrical  Specialty  Co Wilmington.  Del. 

WHAZ      Rensselaer  Polytechnic  Institute Troy,  N.  Y. 

WHB         Sweeney  School  Co Kansas  City,   Mo. 

WHBA      C.  C.  Shaffer Oil  City,  Pa. 

WHBB      Hobel's  Store Stevens   Point.   Wis. 

WHBC      Rev.  E.  P.  Graham Canton,  Ohio 

WHBD     Chas.  W.  Howard Bellefontaine.  Ohio 

WHBF      Beardsley  Specialty  Company Rock  Island,  Illinois 

WHBG      John  S.  Skane Harrisburg,  Pa. 

WHBH     Culver  Military  Academy Culver,  Ind. 

WHBJ      Lauer  Auto  Co Ft.  Wayne.  Ind. 

WHBK     Franklin  St.  Garage,  Inc Ellsworth,  Me. 

WHBL      James  H.  Slusser Logansport.  Ind. 

WHBM     C.  L.  Carroll.  Portable  Station Chicago.  111. 

WHBN      First  Ave.  Methodist  Church St.  Petersburg.  Florida 

WHBP      Johnstown  Automobile  Co Johnstowm,  Pennsylvania 

WHBQ     St.  John's  M.  E.  Church  South Memphis.  Tenn. 

WHBR      Scientific  Electric  &  Mfg.  Co..  3664  Vine  St Cincinnati.  Ohio 

WHBU      Riviera  Theatre  and  Bing's  Clothing Anderson.  Ind. 

WHBV      Fred  Rays  Radio  Shop Columbus.  Ga. 

WHBW     D.  R.  Kienzle Philadelphia.  Pa. 

WHBY     St.  Norbort's  College West  De  Pore.  Wis. 

WHEC      Hickson  Electrio  Co..  Inc Rochester,  N.  Y. 

WHK        Radiovox  Company Cleveland.  Ohio 

WHN         George  Schubert New  York.  N.  Y. 

WHO        Bankers'   Life  Co Des  Moines,  la. 

WHT        Wrigley    Building    .  Chicago Deerfield.    III. 

WIAD       Howard  R.  Miller '. Philadelphia,  Pa. 

WIAQ       Chronicle    Publishing    Co Marion.    Ind. 

WI  AS        Home    Electrio    Co Burlington,    Iowa 

WIBA       The   Capital-Times    Studio Madison.    Wis. 

WIBC  L-.  M.  Tate  Post,  No.  29,  Veterans  of  Foreign  Wars ...  St.  Petersburg,  Florida 

WIBD       X-L  Radio  Service Joliet.  Hlinois 

WIBE        Martinsburg  Radio  Broadcasting  Co Martinsburg,  W.  Va. 


416 

WIBG 

275 

WIBO 

214 

WIBH 

256 

WIBI 

268 

WIBJ 

516 

WIBK 

365 

WIBL 

365 

WIBP 

263 

WIBQ 

268 

WIBR 

393 

WIBS 

244 

WIBT 

236 

WIBU 

229 

WIBW 

258 

WIBX 

268 

WIL 

278 

WIP 

229 

WJAB 

227 

WJAD 

278 

WJAG 

252 

WJAK 

240 

WJAM 

234 

WJAR 

256 

WJAS 

258 

WJAZ 

233 

WJBA 

258 

WJBB 

233 

WJBC 

256 

WJBD 

441 

WJD 

278 

WJJD 

250 

WJY 

485 

WJZ 

280 

WKAA 

286 

WKAD 

283 

WKAQ 

286 

WKAR 

273 

WKAV 

293 

WKBE 

389 

WKBF 

275 

WKBG 

270 

WKY 

273 

WLAG 

233 

WLAL 

242 

WLAP 

246 

WLAQ 

248 

WLAX 

370 

WLB 

273 

WLBL 

242 

WLS 

226 

WLTS 

280 

WLW 

270 

WMAC 

283 

WMAF 

475 

WMAK 

205 

WMAL 

285 

WMAN 

266 

WMAQ 

WMAY 

280 

472 

WMAZ 

273 

WMBB 

275 

WMBF 

250 

WMC 

234 

WMCA 

226 

WMH 

261 

WNAC 

273 

WNAD 

236 

WNAL 

255 

WNAP 

452 

WNAR 

309 

WNAT 

254 

WNAX 

394 

WNYC 

217 

WOAC 

252 

WOAE 

233 

WOAG 

248 

WOAI 

252 

WOAN 

360 

WOAO 

244 

WOAR 

266 

WOAT 

217 

WOAV 

226 

WOAW 

240 

WOAX 

248 

woe 

234 

WOCL 

227 

WODA 

234 

WOI 

229 

WOO 

315 

WOR 

236 

WORD 

252 

WOS 

218 

WOWL 

250 

WOWO 

261 

WPAB 

236 

WPAC 

370 

WPAJ 

319 

WPAK 

379 

WPAL 

535 

WPG 

280 

WQAA 

222 

WOAC 

283 

WQAE 

278 

WQAM 

240 

WQAN 

275 

WQAO 

399 

WQJ 

231 

WRAF 

360 

WRAK 

385 

WRAM 

365 

WRAQ 

250 

WRAV 

240 

WRAW 

245 

WRAX 

222 

WRBC 

222 

WRC 

231 

WREO 

222 

WRHF 

234 

WRNY 

231 

WRK 

220 

WRL 

233 

WRM 

258 

WRMU 

256 

WRW 

233 

WSAC 

216 

WSAG 

218 

WSAI 

244 

WSAJ 

215 

WSAN 

250 

WSAP 

258 

WSAR 

273 

WSAU 

360 

WSAV 

526 

WSAY 

238 

WSAZ 

254 

WSBF 

226 

WSBC 

283 

WSB 

236 

WSKC 

222 

WSMB 

200 

WSMH 

210 

WSMK 

St.  Paul's  Protestant  Episcopal  Church Elkins  Park.  Pa. 

Nelson     Brothers Chicago,     111. 

Elite-Radio  Stores New  Bedford,   Mass. 

Frederick  B.  Zitteli,  Jr Flushing.  N.  Y. 

C.  L.   Carrell   (Portable) Chicago.   111. 

University   of   Toledo Toledo,    Ohio 

McDonald  Radio  Co.,  Portable  Station .Joliet,  HI. 

First    Presbyterian    Church Meiridian,    Miss. 

F.  M.  Schmidt Farina,  111. 

Thurman  A.  Owings Werton.  W.  Va. 

New  Jersey  Nat'l Guard  Hdqs.  Co Elizabeth,  N.  J. 

Orlando  Edgar  Miller  (Portable  Station) New  York,  N.  Y. 

The  Electric  Farm Poynette,  Wis. 

Dr.  L.  L.  Dill Logansport,  Ind. 

Grid-Leak,  Inc Utica,  N.  Y. 

Continental  Electric  Supply  Co Washington,  D.  C. 

Gimbel   Bros Philadelphia,    Pa. 

American   Electric   Co Lincoln,   Nebr. 

Jackson's  Radio  Engineering  Laboratories Waco,  Texas 

Norfolk  Daily  News Norfolk,  Nebr. 

Clifford  L.  White Greentown,  Iowa 

D.  M.  Perham Cedar  Rapids,  Iowa 

The  Outlet  Co.  (J.  Samuels  &.  Bro.) Providence,  R.I. 

Pittsburgh    Radio   Supply   House Pittsburgh,   Pa. 

Chicago     Radio    Laboratory Chicago,    111. 

D.    H.    Lentz,   Jr Joliet,   111. 

L.  W.  McClurg St.  Petersburg,  Fla. 

Hummer    Furniture    Co LaSalle,    111. 

Ashland  Broadcasting  Committee Ashland,    Wis. 

Denison  University Granville,   Ohio 

Lodge,  Loyal  Order  of  Moose Mooseheart,  111. 


New  York,  N.Y. 


Suprc 

Radio  Corp.  of  Ameri. 

Radio  Corp.  of  America New  York,  N.  Y. 

H.  F.  Paar Cedar  Rapids.  Iowa 

Chas.  Looff  (Crescent  Park) East  Providence.  R.  I. 

Radio  Corp.  of  Porto  Rico San  Juan,  P.  R. 

Michigan  Agriculture  College , East  Lansing,  Mich. 

Laconia  Radio  Club Laconia,  N.  H. 

K.  &  B.  Electric  Co Webster,  Massachusetts 

Dutee  Wilcox  Flint Cransten,  Rhode  Island 

C.   L.   Carrel,  Portable Chicago.   HI. 

Wky  Radio  Shop Oklahoma  City,  Okla. 

Cutting  &  Washington  Radio  Corp M  inneapolis,  Minn. 

First  Christian  Church Tulsa.  Okla. 

Wm.  V.  Jordan Louisville,  Ky. 

Arthur   E.   Shilling Kalamazoo,    Mich. 

Putnam  Electric  Co Greencastle,  Ind. 

University  of  Minnesota Minneapolis,  Minn. 

Wisconsin  State  Dept.  of  Markets Stevenspoint.  Wis. 

Sears    Roebuck  &   Co Chicago.   III. 

Lane  Technical  High  School Chicago.  III. 

Crosley    Mfg.  Co Cincinnati.    Ohio 

J.  Edw.  Page  (Olive  B.    Meredith) Casenovia.  N.  Y. 

Round  Hills  Radio  Corp Dartmouth,  Mass. 

Norton  Laboratories Lockport.  N.  Y. 

Trenton    Hardware  Co Trenton,    N.    J. 

First  Baptist  Church Columbus.   Ohio 

Chicago    Daily    News Chicago.    111. 

Kingshighway  Presbyterian  Church St.  Louis,   Mo. 

Mercer    University Macon,    Ga. 

Trianon  Ball  Room Chicago,    111. 

Miami  Beach  Hotel Miami    Beach,    Fla. 

Commercial  Appeal Memphis,  Tenn. 

Hotel  McAlpin  (Greeley  Square  Hotel  Co.) New  York  City 

Ainsworth-Gates  Radio  Co Cincinnati,  O. 

Shepard     Stores Boston,     Mass. 

University  of  Oklahoma Norman,  Okla. 

Omaha  Central  High  School Omaha,  Nebr. 

Wittenberg     College Springfield.     Ohio 

First  Christian  Church Butler,  Mo. 

Lennig  Brothers  Co.  (Frederick  Lennig) Philadelphia,   Pa. 

Dakota  Radio  Apparatus  Co Yankton,  S.  Dak. 

Dept.  of  Plant  and  Structures New  York,  N.  Y. 

Page  Organ  Co ' Lima,  Ohio 

Midland  College Fremont,  Nebr. 

Apollo  Theatre  (Belvidere  Amusement  Co.) Belvidere,  111. 

Southern  Equipment  Co San  Antonio.  Texas 

Vaughn  Conservatory  of  Music  (James  D.  Vaughn) ....  Lawrenceburg,  Tenn. 

Lyradion  Mfg.  Co Mishawaka,  Ind. 

Lundskow.  Henry  P Kenosha.  Wis. 

Boyd  M.  Hamp Wilmington,  Del. 

Pennsyvlania   National  Guard.   2:1   Battalion,    112th  Infantry.  ..  .Erie,   Pa. 

Woodmenofthe  World Omaha.  Nebraska 

Franklyn  J.  Wolff Trenton,  N.  J. 

Palmer  School  of  Chiropractic Davenport,  Iowa 

Hotel  Jamestown,  Inc Jamestown,  N.  Y. 

James  K.  O'Dea Paterson,  New  Jersey 

Iowa  State  College Ames,    Iowa 

John  Wanamaker Philadelphia,  Pa. 

L.  Bamberger  and  Co Newark,  N.  J. 

Peoples  Pulpit  Assn Batavia.  111. 

State  Marketing  Bureau Jefferson  City.  Mo. 

Owl  Battery  Company New  O-leans.  La. 

Main  Auto  Supply  Co Fort  Wayne.  Ind. 

Pennsylvania  StateCollege State  College,  Pa. 

Donaldson  Radio  Co Okmulgee,  Okla. 

Doolittle  Radio  Corp New  Haven,  Conn. 

North  Dakota  Agricultural  College Agricultural  College,  N.  D. 

Superior  Radio  &  Telephone  Equipment  Co Columbus,  Ohio 

The  Municipality  of  Atlantic  City Atlantic  City,  N.  J. 

Horace  A.  Beale,  Jr Parkersburg,  Pa. 

E.  B.  Gish Arnarillo.  Texas 

Moore  Radio  News  Station  (Edmund  B.  Moore) Springfield.  Vt. 

Electrical  Equipment  Co Miami.  Fla. 

Scranton  Times Scranton.  Pa. 

Calvary  Baptist  Church New  York.  N.  Y. 

Calumet  Rainbo  Broadcasting  Co Chicago.  111. 

The  Radio  Club  (Inc.) Laporte.  Ind. 

Economy  Light  Co Escabana,  Mich. 

Lombard  College Galesburg,  111. 

St.  Louis  Radio  Service  Co St.  Louis.  Mo. 

Antioch  College Yellow  Springs,  Ohio 

Avenue  Radio  Shop  (Horace  D.  Good) Reading,  Pa. 

Flaxon's  Garage .Gloucester,  City  N.  J. 

Imanuel  Lutheran  Church : Valparaiso,  Ind. 

Radio  Corp.  of  America Washington,  D.  C. 

Reo  Motor  Car  Co Lansing,  Mich. 

Washington  Radio  Hospital  Fund Washington,  C.  D. 

Experimenter  Publishing  Co New  York,  N.  Y. 

Doron  Bros Hamilton,  Ohio 

Union  College Schenectady,  N.  Y. 

University  of  Hlinois. Urbana.  111. 

A.  H.  Grebe  &  Co..  Inc.,  Motor  Yacht  "MU-1" New  York,  N.Y. 

Tarrytown  Radio  Res.  Labs Tarrytown.  N.  Y. 

Clemson  Agricultural  College Clemson  College.  S.  C. 

Loren  Vanderbeck  Davis St.  Petersburg,  Fla. 

United  States  Playing  Card  Co Cincinnati,  Ohio 

Grove  City  College Grove  City,  Pa. 

Allentown  Call  Publishing  Co AUentown,  Pa. 

Seventh  Day  Adventist  Church New  York,  N.  Y. 

Daughty  &  Welch  Electrical  Co Fall  River.  Mass. 

Camp  Marienfield    Chesham,  New  Hampshire 

C.  W.  Vick  Radio  Construction  Co Houston,  Texas 

Irving  Austin  (Port  Chester  Chamber  of  Commerce)    . .  Port  Chester,  N.  Y. 

Chas.  Electrio  Shop Pomeroy.  Ohio 

Stix-Baer-Fuller  D.  G.  Co St.  Louis,  Mo. 

World  Batley  Co 1219  S.  Wabash  Ave.,  Chicago,  111. 

Atlanta  Journal Atlanta.  Ga. 

World's  Star  Knitting  Co Bay  City,  Mich. 

Saenger  Amusement  Co.  and  Maison  Blanche  Co New  Orleans,  La. 

Shattuck  Music  House Owosso,  Mich. 

8.  M.  K.  Radio  Corp Dayton,  Ohio 


222 
226 
209 
219 
216 
205 
216 
210 
205 
246 
203 
211 
222 
220 
205 
360 
509 
229 
352 
283 
254 
268 
306 
286 
268 
207 
207 
234 
233 
229 
303 
455 
455 
278 
240 
340 
285 
254 
231 
286 
216 
275 
417 
250 
286 
283 
231 
278 
278 
344 
258 
422 
261 
440 
273 
256 
286 
447 
280 
261 
250 
384 
503 
341 
321 
284 
258 
255 
271 
230 
254 
248 
526 
260 
280 
274 
392 
280 
369 
225 
360 
242 
526 
240 
484 
275 
203 
207 
509 
405 
275 
440 
270 
227 
283 
360 
268 
283 
286 
300 
270 
234 
275 
283 
280 
260 
447 
224 
256 
244 
263 
242 
238 
268 
278 
468 
286 
256 
258 
360 
270 
273 
236 
273 
336 
264 
325 
258 
229 
263 
254 
229 
360 
233 
258 
275 
210 
428 
261 
319 
240 
275 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


69 


Little  Gwen  Ponders  the  Radio 
Situation 

(Continued  from  page  65) 
assignment  and,  when  his  fair  passengei 
murmured  "radio  station,"  he  took  her 
to  the  only  one  he  had  ever  been  able 
to  get  on  his  set.  When  she  got  to  the 
other  station  the  announcer  grabbed 
her  because  he  himself  was  a  bit  shy  on 
talent  that  night. 

At  another  time  we  had  a  singer  come 
into  the  studio  chewing  gum  violently. 
When  it  came  time  for  her  numbers  she 
took  the  chewing  gum  out  of  her  mouth, 
parked  it  on  the  counter  by  the  side  of 
the  microphone  and  then  triumphantly 
stepped  before  the  horn  and  began  to 
sing.  After  her  number  was  concluded 
she  returned  for  her  chewing  gum,  smiled 
ecstatically  and  departed. 

All  this  time  we  were  striving  des- 
perately to  compete  with  the  other  sta- 
tion. When  our  fan  mail  dwindled  (we 
never  did  get  much,  by  the  way)  we 
faked  letters. 

Since,  as  I  said  before,  I  wrote  all  the 
stories  that  appeared  in  the  radio  section 
of  the  paper,  the  faked  letters  had  to  be 
put  in  and  they  had  to  be  written  by  me. 

I  want  it  understood  that  I  didn't 
actually  write  letters  and  sign  names  to 
them  to  put  in  the  paper.  I  merely 
quoted  excerpts  from  letters  alleged  to 
have  been  received.  Often  I  would  begin 
my  story  of  the  preceding  night's  pro- 
gram with  a  line  from  these  letters. 

I  must  have  run  out  of  original  things 
to  say  for  unconsciously  I  began  using  the 
phrase,  "Fine,  WPO!"  at  the  beginning 
of  the  majority  of  my  stories.  It  got  to 
be  a  joke  around  the  office.  Every  time 
I  would  come  in  in  the  morning  a 
regular  chorus  would  go  up  from  the 
reporters  and  copy  readers,  "Fine,  WPO!" 

The  Cruel  Finish 

TRY  as  I  would,  there  was  no  way  to 
stem  the  tide  of  artists  that  was 
constantly  flowing  to  the  other  station. 
Too,  rumors  were  rife  that  the  morning 
paper  was  contemplating  erecting  a 
radio  station  that  would  rank  with  the 
best  in  the  country.  With  these  two 
stations  in  the  field  against  us,  our  posi- 
tion was  hopeless  unless  we  installed 
a  powerful  set. 

We  closed  the  station  a  few  days  before 
Christmas.  I  wanted  to  give  some  reason 
for  leaving  the  air  and  to  tell  our  listeners 
(granting  that  we  still  had  any),  that  we 
would  be  with  them  no  longer. 

However,  the  publisher  of  our  news- 
paper did  not  want  that.  He  instructed 
me  to  continue  the  final  program  in  the 
usual  manner,  sign  off  in  the  ordinary 
way  and  then  simply  cease  to  broadcast. 

We  did  not  carry  a  line  in  the  paper 
about  our  having  closed  our  station. 
Few  knew  when  we  closed  and  still 
fewer  cared. 

Just  the  same,  when  I  go  into  the  beau- 
tiful studios  that  they  have  today  I  am 
not  ashamed  of  that  first  station  of  ours. 
I  am  as  proud  of  it  now  as  I  used  to  be 
when  I  would  take  the  microphone  in 
my  hand  and  tell  that  part  of  the  world 
that  was  able  to  get  us,  that  radio  station 
WPO  was  broadcasting. 


Simplify  Radio 

Daven 


The  New  Daven  Tube 

Type  MU-20  increases  the  amplification  of  the 
Daven  Super-Amplifier  to  equal  or  exceed  that 
obtainable  with  transformer  coupling.  A  one- 
pur'Hisr.  three-element  tube,  (ivolt,  '  i  ampere 
rXubeTypeMU-6is 

utput  stage— S5. 00. 


-54.00  each.   Daven  P 
recommended  for  last  • 


Daven  Engineers 

Blaze  Another 

Trail 

rPHE  biggest  of  all  the  little 
-*-  things  in  radio  is  the  grid 
leak.  The  Daven  Grid  Leak  is 
known  the  world  over  as  the 
grid  leak  of  permanent,  constant 
value.    It  is  standard. 

Almost  as  important  is  the  con- 
denser. But  grid  condensers 
change  with  temperature  and 
humidity.  The  mica  in  condens- 
ers lacks  uniformity  or  is  im- 
pure. The  tin  foil  plates  melt  or 
change  their  capacity. 

In  their  constant  efforts  always 
to  simplify  and  to  improve, 
Daven  engineers  have  made  a 
remarkably  effective  combina- 
tion of  grid  leak  and  condenser. 
Two-in-one ! 


The  DAVEN 
LEAKAN- 
DENSER 

IT  is  so  simple, 
so  effective  and 
so  sturdy  that  you 
will  wonder  why 
it  was  not  thought 
of  before. 
Similar  in  size  to 
the  Daven  Grid 
Leak,  it  takes  the 
place  of  the  usual 
grid  condenser 
which  has  shunted 
around  it  the 
usual  grid  leak. 
Made  with  five 
different  values  of 
grid  leak  resis- 
tance, 2,  3,  4,  5, 
and  7  megohms. 
The  grid  condens- 
er capacity  is  fixed 
and  correct  for  all 
makes  of  detector 
tubes. 

With  every  Leak- 
andenser  a  pair 
of  new  snap  fas- 
tener clips  that  do 
not  permit  it  to 
shake  out.  Pre- 
cision-Built. Price 
$1.00  each. 

Manufacturers  are 
invited  to  send  for  a 
sample. 


The  Handbook 
of  resistance  cou- 
pled  amplifi- 
cation. 

The  authority  on 
this  important 
subject  is  THE 
BESIST  O  R 
MANUAL.  At 
your  dealer's  25c. 
By  mail  postpaid 
35c. 


r 


USE  THIS  FREE  COUPON 

DAVEN  RADIO  CORPORATION 

158-160  Summit  Street,  Newark,  Ne 

Please  send  me  the  following 

Q  Resisto. 

|     |  Com  pi* 


Jersey 

n  Resistance  Coupled  Amptificatic 
Manual.     25c  is  enclosed, 
e  catalog  (free;.    Check  one. 


For  Dealers: 
t  distributor 


•  letterhead  or  card, 
ate  with  you. 


THE     BIG     LITTLE     THINGS     OF     RADIO 


Copies  of  August  Radio  Age  Now  Available— 50c 


Chart  Your  Radio 


EXPLOITS! 


GET  this  marvelous  new  help  for  radio  explorers 
— a  beautiful  Air  Map,  printed  in  three  colors, 
with  every  station  clearly  marked  and  Time  zones 
outlinedl     Size,  28  x  34  inches.    There's  no  limit  to 
the  useful  and  amusing  ways  you  can  use 
COLLIER'S  NEW  RADIO  MAP 
of  the  U.  S.  and  CANADA 
With  its  help  you  can  find  out  instantly  how  far  any 
station  is.     If  you  use  a  directional  aerial,  you  can 
point  the  loop  exactly  toward  the  station  you  want 
to  get.    The  map  also  outlines  the  radio  districts,  and 
gives  an  alphabetical  list  of  all  stations  and  their 
operators. 

Thousands  have  already  been  sold.  Get  yours 
to-dayl  At  your  news  stand  or  radio  dealer's,  only 
25  cents — or  just  mail  a  quarter  to  us. 

P.  F.  COLLIER  &  SON  COMPANY 
244  Park  Avenue  New  York  City 

#"     Tested  and  Approved  by  RADIO  AGE     V 


GEM  TUBE 


A  Guaranteed   Radio  Tube 
W  thin  Reach  of  All 

Every     tube     guaranteed.      A 

tube  for  a  dollar  of  $2  value. 

A    trial    order    will    convince 

you    as    it    has    thousands    of 

others.    Send   your   orders   at 

once. 

Orders   sent   C.    O.   J>.    parcel 

post. 

Type.. 20 1 A 

Type. .200 

Type    .199 

Type....l99A 

(with  standard   base)  EACH 

Dealer,    Write   for    Discount! 

GEM   TUBE  CO. 

Dept.  R.  A.  200  Broadway, 
N.  Y.  C.  220  SO.  State  St.. 
Chicago,  III.  Lafayette  Bldg.. 
Detroit,    Mich. „__ 


$1.00 


70 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


WSOE  School  of  Engineering Milwaukee,  Wis.  246 

WSRF  Hardem  Salea  and  Service Broadlanda,  111.  233 

WSTA  Camp  Marienleld Chesham,  N.  H.  229 

WSUI  State  University  of  Iowa Iowa  City,  Iowa  498 

WTAB  Fall  River  Daily  Herald  Publishing  Co Fall  River,  Mass.  248 

WTAC  Penn  Traffic  Co Johnstown,  Pa.  360 

WTADJ  Robt.  E.  Compton Carthage,  111.  236 

WTAL  Toledo  Radio  &  Electric  Co Toledo,  Ohio  252 

WTAP  Cambridge  Radio  i  Electric  Co Cambridge,  111.  242 

WTAQ  S.  H.  Van  Gordon  &  Son Osseo,  Wis.  220 

WTAR  Reliance  Electric  Co Norfolk,  Va.  280 

WTAS  Charles  E.  Erbstein Elgin,  111.  301 

WTATJ  Edison  Electrio  Illuminating  Co (portable)  Boston,  Mass.  244 


WTAW  Agricultural  &  Mechanical  College  of  Texas College  Station.  Texas  280 

WTAX  Williams  Hardware  Co Streator.  111.  231 

WTAZ  Thomas  J.  McGuire Lambertville,  N.  J.  283 

WTHS  Flint  Senior  High  School Flint,  Mich.  218 

WTG  Kansas  State  Agricultural  College Manhattan,  Kans.  273 

WTIC  Travelers  Insurance  Co Hartford,  Conn.  323 

WTX  H.  G.  Sial  Co Chicago,  111.  268 

WW  AD  Wright  &  Wright  (Inc.) .• Philadelphia,  Pa.  360 

WWAE  The  Alamo  Ball  Room J0liet,  111.  242 

WWI  Ford  Motor  Co Dearborn,  Mich.  273 

WWJ  Detroit  News  (Evening  News  Assn.) Detroit,  Mich.  352 

WWL  Loyola  University ,  ,  New  Orleans,  La.  260 


Canadian  Stations 


CFAC  Calgary  Herald .,..,,,,,,, ..,,...... Calgary, 

CFCA  Toronto  Star  Pub.  &  PrtE.  Co Toronto 

CFCF  Marconi  Wireless  Teleg.  Co.,  (Ltd.)  Canada Montreal, 

CFCH  Abitibi  Power  &  Paper  Co.,  (Ltd.) , Iroquois  Falls. 

CFCK  Radio  Supply  Co Edmonton, 

CFCN  W.  W.  Grant  (Ltd.) Calgary. 

CFCR  Laurentide  Air  Service Sudbury, 

CFCT  Victoria  City  Temple Victoria. 

CFCU  The  Jack  Elliott  (Ltd.) Hamilton, 

CFHC  Henry  Birks  &  Sons Calgary. 

CFKC  Thorold  Radio  Supply Thorold. 

CFQC  The  Electrio  Shop  (Ltd.) Saskatoon, 

CFRC  Queens  University Kingston, 

CFXC  Westminster  Trust  Co , Westminister, 

CFYC  CommereialRadio  (Ltd.) Vancouver. 

CHBC  The  Calgary  Albertan Calgary. 

CHCM  Riley  &  McCormack  (Ltd.) Calgary. 

CHCS  Tho  Hamilton  Spectator Hamilton. 

CHIC  Northern  Electric  Co Toronto, 

CHNC  Toronto  Radio  Research  .Society.  ... Toronto, 

CHUC  International  Bible  A.ss'n Saskatoon 

CHXC  R.  Booth,  Jr Ottawa, 

CHYC  Northern  Electrio  Co Montreal 


Alta. 

434 

CJCA 

.Ont. 

357 

CJCL 

.  Que 

411 

CJGC 

Ont. 

500 

CKAC 

Alta. 

517 

CKCD 

Alta. 

434 

CKCK 

,  Ont. 

410 

CKCO 

B.  C. 

329 

CKCX 

Ont. 

341 

CKFC 

Alta. 

434 

CKLC 

Ont. 

248 

CKNC 

Sa.sk. 

329 

CKOC 

.Ont. 

450 

CKY 

B.  C. 

291 

CNRA 

B.C. 

411 

CNRC 

Alta. 

434 

CNRE 

Alta. 

434 

CNRM 

,Ont. 

341 

CNRO 

Ont. 

357 

CNRR 

Ont. 

357 

CNRS 

Sask. 

329 

CNRT 

Ont. 

434 

CNRV 

Que. 

411 

CNRW 

Edmonton  Journal , Edmonton.  Alta.  511 

A.  Couture Montreal,  Que.  270 

London  Free  Press London,  Ont.  329 

La  Presse Montreal,  Que.  411 

Vancouver  Daily  Province Vancouver,  B.  C.  397 

Leader  Pub,  Co Regina,  Sask.  476 

Ottawa   Radio  Association Ottawa,  Ont.  434 

P.  Burns  &  Co.,  (Ltd.) Calgary,  Alta.  434 

First  Congregational  Church Vancouver,  B.  C.  411 

"Wilkinson  Electric  Co.,  (Ltd.) Calgary,   Alta.  434 

Canadian  National  Carbon  Co Toronto,  Ont.  357 

Wentworth  Radio  Supply  Co Hamilton,    Ont.  341 

Manitoba  Tel.  System Winnipeg,  Man.  384 

Canadian  National  Railways Moncton,  N.  B.  312 

Canadian  National  Railways Calgary,  Canada  434 

Canadian  National  Railways Edmonton,  Alta.  517 

Canadian  National  Railways Montreal,  P.  Q.  411 

Canadian  National  Railways Ottawa,  Ont.  434 

Canadian  National  Railways Regina,  Sask.  476 

•Canadian  National  Railways Saskatoon,  Sask.  329 

Canadian  National  Railways Toronto,    Ont.  357 

Canadian  National  Railways Vancouver,  B.  C.  411 

Canadian  National  Railways , Winnipeg,   Man.  384 


Cuban  Stations 


PWX  Cuban  Telephone  Co Habana 

2DW  Pedro  Zayas Habana 

2AB  Alberto  S.  de  Busta.ma.nte Habana 

20K  Mario  Garcia  Vs'ez Habana 

2BY  Frederick  W.  Borton Habana 

2CX  Frederick  W.  Borton Habana 

2EV  WestinRhouse  Elec.  Co Habana 

2TW  Roberto  E.  Ramires Habana 

2HC  Heraldo  de  Cuba Habana 

2LC  Luis  Casas Habana 

2KD  E.  Sanchez  de  Fuentes Habana 

2MN  Fausto  Simon Habana 

2MG  Manuel  G.  Salaa Habana 

2JD  Raul  Parez  Falcon , Habana 


400 

2K 

300 

2HS 

240 

20L 

360 

2WW 

260 

5EV 

320 

6KW 

220 

6KJ 

230 

6CX 

275 

6DW 

250 

6BY 

350 

6AZ 

270 

8BY 

280 

8FU 

105 

8DW 

Alvara  Daza Habana  200 

Julio  Power Habana  180 

Oscar  Collado -. Habana  290 

Amadeo  Saenz Habana  210 

Leopoldo  E.  Figueroa Colon  360 

Frank  H.  Jones Tuinucu  340 

Frank  H.  Hones Tuinucu  275 

Antonio  T.  Figueroa Cienfiegos  170 

Eduardo  Terry Cienfiegos  225 

Jose  Ganduxe Cienfiegos  300 

Valentin  Ullivarri Cienfiegos  200 

Alberto  Ravelo Stgo.  de  Cuba  250 

Andres  Vinnet Stgo.  de  Cuba  225 

Pedro  C.  Anduz Stgo.  de  Cuba  275 


European  Broadcasting  Stations 


British  Stations 


2LO  London 365  5NO 

SIT  Birmingham 475  5SC 

5WA  Cardiff 350  2BD 

6BM  Bournemouth 3S5  6SL 

2ZY  Manchester 375 


Newcastle 400 

Glasgow 420 

Aberdeen 492 

Sheffield  (relay  station) 303 


French  Stations 


A    NEW    HI-MU    TUBE 

The  HI-CONSTRON  Tube 

__  Model  C.  T.  101A 

^£«  A  CLEARTRON  PRODUCT 

For  Resistance  Coupled  Amplifiers 

The  Hi-Constron  is  a  Hi-Mu  tube  with  an  amplication  constant  of  20  that  has 
been  especially  designed  for  Resistance  Coupled  Amplifiers.  The  Hi-Constron 
was  the  first  Hi-Mu  tube  offered  for  sale  to  the  general  public  and  is  the 
result  of  years  of  research  work. 

Others  may  imitate  the  Hi-Constron  as  to  its  appearance  but  none  surpass 
its  duality  pr|ce    $3  00 

We  also   manufacture 

CT  201A  CT  199  Standard  Base 

CT  199  Small  Base  CT  400  Rectron  for  B  Battery  Eliminators 

List  Price  of  all  types,  $2.50 

CLEARTRON  VACUUM  TUBE  COMPANY 

28  West  44th  St.,  New  York,  N.  Y. 
Factory  -  West  New  York,  N.  J. 


%j4L-*dk/  LOW  WAVE 
H|  V™     LOW  LOSS  | 

UNCLE  SAM 
COIL 


• 

size         ; 

Tunes  from 

37  to  ISO 

meters 

with 

a  .0005  MFD. 

Condenser 


Ask  your  dealer  or  send  us  four  cents 
in  stamps  for  wiring  diagrams  in 
ivhich   this   unit   can   be   used 


UNCLE   SAM   ELECTRIC  CO. 

E.    Sixth   St.  Plainfield,    N.    J. 


s^aassasggasBfflg 


J 


*     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


71 


CLASSIFIED  ADVERTISEMENTS 

If  you  have  anything  to  buy  or  sell,  don't  overlook  the  value  of  RADIO  AGE'S  classified 
advertisements.    Many  such  messages  have  paved  the  way  to  independent  incomes. 

The  classified  advertising  rates  are  but  ten  cents  per  word  for  a  single  insertion.  Liberal 
discounts  are  allowed  on  three,  six  and  twelve-time  insertions,  of  five,  fifteen  and  thirty  per  cent 
respectively.  Unless  placed  through  an  accredited  advertising  agency,  cash  should  accompany 
all  orders.  Name  and  address  must  be  included  at  foregoing  rates  and  no  advertisement  of  less 
than  ten  words  will  be  accepted. 

All  classified  ads  for  the  October  issue  must  be  sent  in  by  September  1 . 


ADVERTISING     SERVICE 


QUF.X   Sales 
today.      Que 


Letters   Get    More    Businc 
,  4416  Michigan  Ave.,  Chit 


ENGINEERS  about  to  begin  six-months'  research  trip 
to  territory  West  of  the  Mississippi,  between  Canada  and 
Mexico,  are  willing  to  consider  propositions  for  taking 
on  radio  lines  on  a  distribution  basis,  with  a  view  to 
establishing  dealers,  jobbers,  agents,  etc.,  in  sparsely 
settled  districts.  Such  territory  would  be  exclusively 
apportioned.  Address  all  communications  in  confi- 
dence. Only  reputable  lines  and  concerns  will  be  con- 
sidered. 100  per  cent  distribution  and  advertising 
representation  assured  at  minimum  per  capitaTcost. 
Address,  Harvey  T.  Kelley,  Suite  301,  210  East"  Ohio 
Street,  Chicago,  111. 


AGENTS  WANTED 


FORDS.  60  miles  on  one  gallon  of  Gas.  It  has  been 
proven  such  mileage  can  be  made.  AIRLOCK  guar- 
antees to  increase  gas  mileage;  also  prevents  radiator 
boiling  in  summer  or  freezing  in  winter.  Cools,  Fuels, 
Decarbonizes  the  Ford  motor.  Splendid  territory 
open.  AIRLOCK  PRODUCTS.  Box  703G,  Willow  Street, 
Long  Beach,  Calif. 


RADIO — Join  our  sales  organization  and  make  big 
money.  We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers. Widener  of  Kansas  City  makes  $150.00 
weekly.  You  can  do  as  well  or  better.  Write  today 
for  catalog,  and  discounts.  Name  your  county.  Wave- 
land  Radio  Company,  Div.  52,  1027  No.  State  St.,  Chi- 
cago. 111. 


MANUFACTURER'S  AGENT  calling  on  Radio-Elec- 
trical Jobbers,  Chicago  and  vicinity,  has  opening  for  3 
additional  lines  carrying  volume  business,  as  we  cater 
to  large  jobbers.  Edelstein,  1804  McCormick  Bid., 
Chicago. 


AGENTS—WRITE  FOR  FREE  SAMPLES.  Sell  Madison 
"Better-Mads  "  Shirts  lor  large  manufacturer  direct  to 
wearer.  No  capital  or  experience  required.  Many 
earn  $100  weekly  and  bonus.  MADISON  MFGRS.,  501 
Broadway,  New  York. 


90c  an  hour  to  advertise  and  distribute  samples  to  coi 
Write    quick    for    territory    and     particular 
-~i  Products  Co.,  2130  American  Building,  Cii 


Man  wanted  for  this  territory  to  sell  wonderful 
value  men's,  women's,  Children  s  shoes  direct,  sav- 
ing consumer  over  40%.  Experience  unnecessary. 
Samples  supplied.  Big  weekly  permanent  income. 
Write  today  Tanners  Mfg.  Co.,  1334C.  St.,  Boston,  Mass. 


<B"   BATTERIES 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parts  and  plana — complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake,  Chicago. 


BATTERIES  FOR  SALE— Four  2 4- volt  "Main"  Storage 
"B"  Batteries,  never  used,  shipped  and  ready  to  wire 
for  $38.00.  First  order  gets  the  batteries.  Address 
Box  B,  Radio  Age,  500  N.  Dearborn  St.,  Chicago,  HI. 


CRYSTALS 


TESTED  GALENA  CRYSTALS,  50c  pound  bulk.     Bu* 
kett,  Geologist,  Joplin,  Mo. 


Classified,  ad.  copy  for  the  October 
RADIO  AGE  must  be  sent  in  by 
September  1,  1925. 


HELP  WANTED 


RADIO  SALESMEN  and  SET  BUILDERS— We  need 
you  and  you  need  us.  If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  111. 


MEN  wanting  forest  ranger,  railway  clerk  and  other 
government  positions,  write  for  free  particulars  of 
exams.      Mokane,   Dept.    B-33,   Denver,   Colo. 


INVENTIONS 


NEW  IDEAS  WANTED— Well  known  Radio  Manufac- 
turer whose  products  are  nationally  advertised  and  sold 
everywhere  wants  new  Radio  device  to  sell.  Will  pay 
outright  or  royalty  for  idea  or  invention  which  is  really 
new  and  saleable.  Address:  Mr.  R.  F.  Devine,  Room 
1101,  116  West  32nd  St.,  New  York,  N.  Y. 


MANUFACTURING  FACILITIES 


AN  OLD  AND  WELL  ESTABLISHED  MANUFACTUR- 
ING COMPANY  IN  THE  MIDDLE  WEST  WITH  LARGE 
WELL  EQUIPPED  PLANTS  AND  UNUSUAL  FINAN- 
CIAL RESOURCES,  DESIRING  TO  ENTER  THE  RADIO 
FIELD  WILL  CONSIDER  THE  MANUFACTURE  AND 
SALE  OF  RADIO  SETS  OR  DEVICES  OF  OUTSTAND- 
ING AND  UNUSUAL  MERIT  ON  A  ROYALTY  BASIS. 
ADDRESS  BOX  1A,  RADIO  AGE. 


PATENTS 


FOR  SALE:  U.  S.  and  Canadian  Patent  on  an  Attach- 
ment for  Phonographs;  is  the  most  beautiful  inven- 
tion of  the  age.    Address  Chas.  F.  Smith,  Huff,  N.  Dak. 


PERSONAL 


LONELY  HEARTS:  Exchange  letters;  make 
new  friends  in  our  jolly  club.  Eva  Moon 
Jacksonville,  Florida.    Enclose  stamp. 


Look!  You  Radio  Bugs!  Join  Radio  Correspondence 
Club.  Entirely  new.  Broaden  your  acquaintance, 
exchange  ideas.  Membership  open  to  LADY  BUGS 
also.  Dime  stamp  brings  pamphlet  and  Radio  Novelty 
Cards.     Radio  Rose,  Box  662,  Cleveland,  Ohio. 


PRINTING 


WE    print    Stationery,    Booklets,    Catalogs,    Circulars. 
Samples.     Commercial  Press,  Batavia,  Ohio. 


RADIO 


A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  III. 


Standard  soderless  radio  Jacks.  Binding  post  attach- 
ments. Double  circuit.  One  dollar  bill.  Postpaid. 
Clinton  Seward,  Jr.,  New  Paltz,  New  York,  N.   Y. 


15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.      Every  item  guaranteed.     Tell 
IMPERIAL  RADIO  COMPANY,  Deli 


1  us  your  t 
e,  Ohio. 


RADIO  SETS.  Our  prices  save  you  money.  Lists  free. 
The  Radio  Shoppe,  Box  645,  East  Liverpool,  Ohio. 

AT  LAST  The  Radio  Static  Eliminator.  Eliminate! 
50  to  90%  Static.  Many  satisfied  users.  Write  foi 
particulars.  Radio  Specialties  Company,  Sioux  Falls, 
South   Dakota. 


RADIO  DEALERS 


DEALERS — Write  for  our  illustrated  catalog  of  reliable 
Radio  Merchandise.  Rossiter-Manning  Corporation, 
Dept.  D,  1830  Wilson  Ave.,  Chicago,  111. 


RADIO  SUPPLIES 


WE  CAN  SAVE  You  money  on  radio  supplies.  30  per 
cent  discount  AND  MORE  on  tubes,  batteries,  loud 
speakers,  static  eliminators,  condensers,  transformers. 
German  silver  wire,  and  all  standard  radio  apparatus 
We  buy  in  quantity  lots  to  enable  selling  to  you  whole- 
sale. Additional  discount  for  cash.  Send  for  catalog 
or  exclusive  proposition  for  your  territory.  Address, 
Box  9A,  RADIOGRAPH  LABORATORIES,  1234  Rose- 
mont  avenue,  Chicago,  111.     New  fall  lines  now  ready. 


STAMPS  AND  COINS 


158  Genuine  Foreign  Stamps.  Mexico  War  Issues, 
Venezuela,  Salvador  and  India  Service.  Guatemala, 
China,  etc.,  only  5c.  Finest  approval  sheets,  50  to 
60  per  cent.  Agents  Wanted.  Big  72-p.  Lists  Free. 
We  Buy  Stamps.  Established  20  Years.  Hussman 
Stamp  Co.,  Dept.  152,  St.  Louis,  Mo. 


STAMPS,  50  varieties,  Africa,  Brazil,  Peru,  Cuba, 
Mexico,  etc..  10c.  50  different  U.  S.,  25c;  1,000  mixed, 
40c;  1,000  hinges,  10c.  List  free.  C.  Stegman,  5950 
Cote  Brilliante,  St.  Louis,  Missouri. 


VOCATIONS 


Make    Big     Money.       Safe   and    Lock    Expert.       Wayne 
Strong,  3800  Lan  Franco  St.,  Los  Angeles,  Calif. 


WANTED 

WANTED— To  complete  my  set  RADIO  AGE  need 
August,  September,  October,  November,  1923,  issues, 
bound  or  unbound.  Advise  price.  Lloyd  C.  Henning, 
Hollbrook.  Arizona. 


WIRELESS 


WANT  TO  MEMORIZE  THE  WIRELESS  CODE?  The 
Coryden  Snyder  Code  Method,  Patented,  is  quickest. 
Send  50c  coin,  stamps  or  M.  O.  to  C.  G.  Snyder.  1423 
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TELEGRAPH  Y—Morseand  Wireless— taught  at  home 
in  half  usual  time  and  at  triding  cost.  Omnigraph 
Automatic  Transmitter  will  send,  on  Sounder  or  Buz- 
zer, unlimited  messages,  any  speed,  just  as  expert 
operator  would.  Adopted  by  U.  S.  Govt,  and  used  by 
leading  Universities,  Colleges,  Technical  and  Telegraph 
Schools  throughout  U.  S.  Catalog  free.  Omnigraph 
Mfg.  Co.,  13  F  Hudson  St.,  New  York. 


WRITERS 


RADIO  CIRCUITS 

SPECIAL  FOR    SEPTEMBER 
The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne.  fully 
illustrated,  and  RADIO  AGE,  for  $2.50.      Price  of  Book- 
let alone  is  50c.      Send  check,  currency  or  money  order 
to  RADIO  AGE,  500  N.  Dearborn  Street,  Chicago. 

*     Tested  and  Approved  by  RADIO  AGE     # 


NEW  WRITERS  WANTED— Articles,  stories,  poems, 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No.  bunk.)  NOT  A  CORRE- 
SPONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
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subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Los 
Angeles,  Calif. 

WRITERS— Cash  in  on  your  knowledge  of  radio  by 
writing  for  Radio  Magazines  and  Newspaper  Supple- 
ments. Write  up  your  radio  experiences,  your  new 
hook-up,  your  knowledge  of  broadcasting  stations  and 
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work.  FREE  Criticism  and  Advisory  Service  until  your 
manuscript  is  sold!  ALL  Magazines  and  Papers  de- 
manding fiction  and  articles  dealing  with  radio.  Here 
is  YOUR  OPPORTUNITY  to  profit!  Send  for  FREE 
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Willis  Arnold  and  Associates,  210  East  Ohio  St. 
Chicago,  111. 

Make  big  money  writing  Movie  Plays.  Circulars  free 
W.    C.    Krug,    Ashton,    Illinois. 


Have  you  ordered  your 
October  Radio  Age? 


72 


RADIO  AGE  for  September,  1925 


The  Magazine  of  the  Hour 


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POLK'S  REFERENCE  BOOK 

FOR    DIRECT    MAIL   ADVERTISERS 

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Branches    In    principal    cities   of   U.    S. 


THE    RADIO    AGE 
BUYERS'    SERVICE 

What  do  you  want  to  purchase  in  the  radio  line?  Let  the  staff  of  RADIO  AGE  save  you 
time  and  money  by  sending  in  the  coupon  below.  Enter  the  number  of  the  article  you 
would  like  to  know  more  about  in  the  spaces  provided  in  the  coupon. 


1  "A"  Batteries 

2  Aerial  protector* 

3  Aerial  insulators 

4  Aerials 

5  Aerials,  loop 

6  Amplifiers 

7  Amplifying  units 

8  Ammeters 

9  *'B"  batteries 

10  Batteries   (state  voltage) 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery  substitutes 

17  Bezels 

18  Binding  posts 

19  Binding  posts,  insulated 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatstone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisers 

33  Coils 

34  Coils,  choke 

35  Coils,  coupling 

36  Coils,  filter 

37  Coils,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance 

40  Coils,  Reinartz 

41  Coils,  stabilizer 

42  Coils,  tuning 

43  Condenser  parts 

44  Condenser  plates 

45  Condensers,  antenna  coup- 
ling 

46  Condensers,  by-pass 

47  Condensers,  coupling 

48  Condensers,  filter 

49  Condensers,  fixed  (paper, 
grid,  or  phone) 

50  Condensers,  variable  grid 

51  Condensers,  variable  mica 

52  Condensers,  vernier 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  seta 

57  Couplers,  loose 

58  Couplers,  molded 

59  Couplers,  vario 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 

71  Dial,  adjusters 

72  Dials,  composition 

73  Dials,  hard  rubber 

74  Dials,  rheostat 

75  Dials,  metal 

76  Dials,  vernier 

77  Dials  with  knobs 

78  Dies 

79  Drills,  electric 

80  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

83  Enamels,  battery 

84  Enamels,  metal 

85  End  stops 

86  Eyelets 

87  Experimental  work 

88  Fibre  sheet,  vulcanized 

89  Filter  reactors; 

90  Fixtures 

91  Fuse  cut  outs 

92  Fuses,  tube 

93  Generators, high  frequency 

94  Grid  choppers,  rotary 


95  Grid  leak  holders 
[  96  Grid,  transmitting  leaks 

97  Grid  leaks,  tube* 
[  98  Grid  leaks,  variable 
I  99  Grinders,  electric 

100  Ground  clamps 

101  Ground  rods 

102  Handles,  switch 

103  Head  bands 

104  Head  phones 

105  Head  sets 

106  Honeycomb  coil  adapters 

107  Hook  ups 

108  Horns,  composition 

109  Horns,  fibre 

110  Horns,  mache 

111  Horns,  metal 

112  Horns,  wooden 

113  Hydrometers 

114  Indicators,  polarity 

115  Inductances,  C.  W. 

116  Insulation,  molded 

117  Insulation  material 

118  Insulators,  aerial 

119  Insulators,  composition 

120  Insulators,  fibre 

121  Insulators,  high  voltage 

122  Insulators,  cloth 

123  Insulators,  glass 

124  Insulators,  hard  rubber 

125  Insulators,  porcelain 

126  Irons,  soldering 

127  Jacks 

128  Filament  control 

129  Jars,  battery 

130  Keys,  transmitting 

131  Knobs 

132  Knock-down  panel  units 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arresters 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  units 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instruments 

142  Megohmeters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeten 

148  Minerals 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,      condenser 
leak 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,  honeycomb 
coil 

156  Mountings,     inductance 
switch 

157  Name  plates 

158  Neutrodyne  set  parts 

159  Nute 

160  Ohmeters 

161  Oscillators 

162  Panel  cutting  and  drilling 

163  Panels,     drilled     and     un- 
drilled 

164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  soldering 

168  Patent  attorneys 

169  Phone  connectors,  multi- 
ple 

170  Phonograph  adapters 

171  Plates,  condenser 

172  Plugs,  coil 

173  Plugs,  telephone 

174  Pointers,  dial  and  knob 

175  Poles,  aerial 

176  Potentiometers 

177  Punching  machine* 

178  Reinartz  set  parts 

179  Regenerative  set  parts 

180  Receiver  caps 

181  Rectifiers,  battery 

182  Resistance  leaks 

183  Resistance  units 

184  Rheostat  bases 

185  Rheostat  strips 


186  Rheostats,  automatic 

187  Rheostats,  battery 
18S  Rheostats,  dial 

189  Rheostats,  filament 

190  Rheostats,     potentiometer 

191  Rheostats,  power 

192  Rheostats,  vernier 

193  Rods,  ground 

194  Rotors 

195  Scrapers,  wire 

196  Screwdrivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving — cabinet 

200  Seta,  receiving — crystal 

201  Sets,     receiving — knock- 

202  Sets,     receiving  —  Neutro- 

203  Sets,  receiving — portable 

204  Sets,  receiving — radio  fre- 
quency 

205  Sets,     receiving — reflex 

206  Sets,    receiving — regenera- 
tive 

207  Sets,   receiving — Reinartz 

208  Sets,  receiving — sectional 

209  Sets,  receiving — shortwave 

210  Sets,     receiving — super-re- 
generative 

211  Sets,  transmitting 

212  Slate 

213  Shellac 

214  Sliders 

215  Socket  adapters 

216  Sockets. 

217  Solder 

218  Soldering  irons,  electric 

219  Soldering  paste 

220  Solder  flux 

221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 

226  Stampings 

227  Stators 

228  Stop  points 

229  Switch  arms 

230  Switch  levers 

231  Switch  points 

232  Switch  stops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switches,  ground 

237  Switches,  inductance 

238  Switches,  panel 

239  Switches,  single  and  dou- 
ble throw 

240  Tone  wheels 

241  Towers,  aerial 

242  Transformers,    audio    fre- 
quency 

243  Transformers,  filament 

244  Transformers,  modulation 

245  Transformers,  power 

246  Transformers,  push-pull 

247  Transformers,     radio     fre- 
quency 

248  Transformers,  variable 

249  Transmitters 

250  Tubes,  vaccuum — peanut 

251  Tubes,    vacuum — two    ele- 
ment 

252  Tubes,  vacuum — three  ele- 
ment 

253  Tuners 

254  Variocouplers,  hard  rubber 

255  Variocouplers,  molded 

256  Variocouplers,  wooden 

257  Variometers,  hard  rubber 

258  Variometers,  molded 

259  Variometers,  wooden 

260  Varnish,  insulating 

261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 

265  Wire,  aerial 

266  Wire, 'braided  and  stranded 

267  Wire," copper 

268  Wire,  insulated 

269  Wire,  Litz 

270  Wire,  magnet 

271  Wire,  platinum 

272  Wire,  tungsten 


RADIO  AGE  BUYERS'  SERVICE,  500  N.  Dearborn  St.,  Chicago,  111. 

Please  see  that  I  am  supplied  with  buying  specifications  and  prices  on  the  articles  numbered  herewith; 


I      I       I      I       I 


I       I       I       1 


I       I       I 


I  am  a —  Q]  Dealer  ^]  Jobber  1    Mfgrs."  Rep.  □    Manufacturer 

Firm     [If  identified  with  Radio  industry]   

My   Occupation  .„ . . 

My    Name   . - - 


*     Tested  and  Approved  by  RADIO  AGE     * 


There  Is  No  Substitute 
for  Good  Hookups 


What  You  Get : 

The   RADIO   AGE 

ANNUAL  for  1925  is 
brim  full  of  hookups 
and  "how-to-do-it" 
articles.  In  addition 
to  the  array  of  con- 
structional set  arti- 
cles, you  will  find  in- 
structions for  build- 
ing wave  traps,  bat- 
tery chargers,  am- 
plifiers, loud  speak- 
ers, etc.  And  to  top 
it  all  you'll  find  the 
big  32-page  blue- 
print section  con- 
taining the  prize 
hookups  for  1924  and 
1925!  Real  blue- 
prints to  work  by! 
Each  blueprint  is 
worth  the  cost  of 
the  book!  120  pages 
of  features  in  all! 


You  may  try  to  save  money  on  radio  parts — 
you  may  content  yourself  with  a  mediocre,  care- 
lessly-planned radio  set,  but  after  all  is  said  and 
done  and  the  results  given  the  acid  test,  you  will 
find  there  is  no  substitute  for  a  good  radio 
hookup. 

In  choosing  the  hookup  for  your  needs  this 
Fall — the  set  that  will  penetrate  the  strong 
stations  and  bring  in  pleasing  and  clear  DX,  you 
must  get  the  absolute  best  or  you  will  regret 
your  choice  in  the  end,  when  you  will  be  forced 
to  dismantle  the  "just-as-good11  hookup  and 
make  the  real  thing. 

The  RADIO  AGE  ANNUAL  for  1925  contains 
nothing  but  tested  hookups;  circuits  that  have 
emerged  with  flying  colors  from  the  most  strin- 
gent tests  radio  engineers  could  impose.  The 
ANNUAL  does  not  contain  a  hookup  that  will 
not  please  you  in  every  way  and  be  just  as  good  a 
year  from  now  as  it  is  today. 

Before  beginning  your  new  radio  season,  get 
the  ANNUAL  for  1925  and  take  your  pick.  You 
can't  go  wrong.  Only  a  few  hundred  ANNUALS 
left,  at  a  dollar  a  copy.    Get  yours  now! 


$1.00  a         RADIO  AGE  ANNUAL  $1.00  a 

Copy  FOR  1925  Copy 

Some  of  the  Features 


How  to  read  and  understand  hookups. 

How  to  understand  radio  phenomena. 

Building  your  first  simple  set. 

How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set. 

How  to  amplify  any  kind  of  set. 

Making  a  reflex  set. 

Building  your  first  Reinartz  set. 

The  renowned  Baby  Heterodyne  No.  1. 

Adding  audio  and  radio  stages  to  the  Baby  Het. 

How  to  make  a  battery  charger. 

How  to  make  a  loud  speaker. 

RADIO    AGE    ANNUAL    BLUEPRINT    SECTION    with    such 

popular    hookups    as    the    aperiodic    variometer,    loop    sets. 


feedback  receivers,  neutrodynes,  re.lex  hookups.  Baby  Het  No. 
2,  a  Wonder  Super-Het,  and  others. 

How  to  get  rid  of  interference. 

How  to, make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube   trouble. 

Another  super-heterodyne  for  the  super   experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

AND  MANY  OTHER  UP-TO-THE-MINUTE  HOOKUPS  AND 
ARTICLES. 


RADIO  AGE  ANNUAL  COUPON 
RADIO  AGE,  INC., 
500  North  Dearborn  St.,  Chicago,  III. 

Gentlemen:       I   want  to  be  a  proud  owner  of    the  RADIO  AGE  ANNUAL  FOR  1925.     Enclosed  find 
$  1 .00.      I  f  I  am  not  satisfied  with  the  ANNUAL  I  will  return  it  within  five  days  and  you  will  refund  my  dollar. 

Name _ _ - 


Address . 

City 

9-25 


State 


MacMillan  Knew 


When  Commander  MacMillan  chose  Zenith  radio  for  his  latest 
North  Polar  Expedition,  he  knew  from  personal  experience  what 
Zenith  would  do— 

MacMillan  knew  that  Zenith — even  one  of  the  earlier  models — would 
enable  him  to  tune  in  stations  all  over  the  United  States  and  Europe 
— even  far-off  Honolulu. 

MacMillan  knew  that  no  other  radio  equipment  would  give  him  such 
extraordinary  performance,  such  unfailing  service. 

When  Arctic  explorers  of  MacMillan's  calibre  stake  their  lives  — re- 
peatedly—  on  Zenith  performance,  one  reason  only  can  explain  their 
choice — Zenith  has  proved  to  be  the  best  obtainable,  at  any  price. 

Ask  your  nearest  Zenith  dealer  for  a  demonstration. 

Costs  More — but  Does  More! 


ZENITH  RADIO  CORPORATION 

#»,  Straus  Building,  Chicago 


r 


*     Tested  and  Approved  bu  RADIO  AGE 


Blueprint  Section  Every  Month 


o 


1 


our 


w 


v 


m5 


MEET  Y0 


Built  As  Only  B-T  Can  Build 

"No  condenser  is  better  than  its  bearings," — and  no  other  bear- 
ing made  today  approaches  the  mechanical  efficiency  of  the  B-T 
"Lifetime"   bearing. 

You  can  pay  more  for  condensers  but  you  cannot  buy  as  much. 
That's  why  we  print  on  every  carton  "  If  you  don't  find  it  better  send 
it   back.'' 

The  B-T  Straight  Line  Frequency  Condenser 

spaces  stations  evenly  on  the  dial  according  to  frequencies  when 
used  with  B-T  Inductances.    No  condenser,  regardless  of  advertis- 
ing, will  give  straight  line  results  except  with  the  particular  coil 
for  which  they  are  designed. 
The  B-T  S  L  F  follows  the  design  and  mechanical  construction 

of  the  B-T  "Lifetime," — leader  of  the  world  for  the  past  eighteen 

months.     In  buying  a  B-T  product  you  know  you  have  an  original 

and  not  a  copy.     For  your  protection  we  caution  you  to  avoid 

imitations. 

Type  S  L  F— 17  plate,  .0003  5,  is  $5.75. 

The  B-T  Universal  Socket 

eliminates  adapters.     It  takes  the  present  type  and  the  new  UX 
tubes.      You  may  change  to  dry  cell  tubes  without  changing  sockets. 

Positive,  side-wiping,  spring  contacts  insure  results. 

Price — 75c. 

The  B-T  "Euphonic"  Transformer 

Euphonic, — "pleasing  to  the  ear," — is  the  only  term  that  ex- 
presses the  matchless  qualities  of  this  new  product. 

Its  Universal  mounting  feature, — exclusively  B-T, — is  the  first  real  improvement  in  transformer 
mechanical  construction  since  broadcasting    began. 

The  mounting  legs  snap  into  position  readily  in  either  position.  Either  side  may  be  placed  up- 
wards,— the  terminals  may  be  brought  where  you  want  them  and  all  crossed  wiring, — a  most 
frequent  cause  of  howling  and  distortion,  eliminated. 

Fully  shielded,  black  enamelled, — Gold  and  Blue  seal. 
Two  ratios  2.2  to  1  and  5.9  to  1, — small  enough  to  be  compact, — 
Large  enough  that  adding  more  iron  would  be  wasted  material. 
Just  as  much  superior  to  other  transformers  as  every  other  B-T  product  has 
been.     Price,  Low  ratio  $5.00;  High  ratio  $5.75. 


The  B-T  Tun- 
ing Control 

is  proving  to  be  prob- 
ably the  most  popular 
item  we  ever  built. 
We  have  been  greatly 
surprised  at  the  num- 
ber of  people  who  go 
to  the  trouble  of  writ- 
ing    us     letters     after 

PriceLo"!:....$2.50 


The  8th  edi- 
tion of  "BET- 
TER   TUNING" 

we  guarantee  to 
be  the  biggest 
10c  worth  you 
ever  bought.  It 
covers  many  live 
subjects  in  a 
way  that  is  pe- 
culiarly differ- 
ent. Send  the 
coupon    today. 


□ 

□ 
□ 


Send  circulars  on  your  Audio  Transformer,  Universal 
Socket,  Tuning  Control,  High  Resistances,  "Toro- 
style"   Transformers  and  all  B-T  products. 


Send  "Better  Tuning"  8th  Ed. 


I   would  be  interested  in  a  complete  set. 
formation 


10c  enclosed. 

Send  in- 


Name 

Address, 


BREMER-TULLY  MFG.  CO. 


"Pioneers  of  Better  Tuning" 
CANAL  AND  HARRISON 


CHICAGO 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


W50to250aWeekin  RADIO 


Trained 
Men 


Easy  to  Become  a  RADIO  EXPERT  at 
Home  in  Spare  Time 


Proof  that  Radio  Pays 

S^e  What  These  N.  R.  I.  Men  Are  Doing 

Buys  New  Car  With  Earnings 
Anyone,  regardless  of  age 
or  sex.  should  have  no  trouble 
in  mastering  Radio  from  the 
N.  R.  I.  course.  I  am  at  pres- 
ent employed  as  Service  Man- 
ager for  the  Geo.  F.  Dent 
Radio  Service  Co.  and  I  am 
sti  1  taking  the  course. 

I  have  had  great  success 
selling,  building,  repairing  and 
installing  all  kinds  of  Radios.  At  present  I  am 
getting  a  salary  and  commission  which,  although 
I  have  only  been  with  the  firm  for  3  months,  has 
enabled  me  to  purchase  a  new  car. 

Richard  E.  Jones.  Bay  City,  Michigan 

Gets  Own  Manufacturing 
Business 
As  you  can  see  by  our 
letterhead,  Mr.  Bartlet  (one  of 
your  graduates)  and  I  are  in 
business  for  ourselves.  We 
build  6-tube  radio  frequency 
sets  and  have  a  ready  market  ' 
for  them.  This  was  only  made 
possible  through  your  course.  Your  instructioL 
and  Bervice  is  a  great  help.  It  is  impossible  for 
me  to  estimate  its  value  in  dollars  and  cents. 
I  think  Radio  offers  better  opportunities  .than 
anv  other  field. 

Allen  N.  Birtcil,  Knox,  Pa 


MakesS50  to  $80  a  Week  More 
Your  course  leads  so  much 
further  ahead  than  practical 
electricity  that  there  is  noth- 
ing left  to  say.  Since  I  took 
your  course  I  have  earned 
from  $50  to  $80  a  week  more. 
Preston  Fowler,  Gordon,  Neb. 


Increases  Pay  160  Per  Cent 
I  was  just  receiving  $3.00 
per  8  hours  when  I  enrolled 
with  N.  R.  I.  and  now  I  am 
receiving  $1.00  an  hour  (160 
per  cent  increase).  That  is 
where  N.  R.  I.  put  me.  The 
course  has  been  worth  $2500  a 
year  to  me  and  in  another 
year  it  wi  1  be  worth  $3500  a  year. 

Andrew  M.  Shurie,  Latrobe.  Pa 


Big      Jobs     Waiting     in     the     Radio 
Business 

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Up-to-date  Receiving  Sets  Given  with  Course 
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We  are  constantly  in  touch  with  openings  for 
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RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITH  WHICH   IS  COMBINED   RADIO  TOPICS 


Volume  4 


October,  1925 


Number   10 


CONTENTS 

Cover  Design  by  A.  P.  Mehlum 

Auto-Transformer  Coupling 7 

By  Roscoe  Bundy 

Some  Facts  About  Quality 11 

By  Brainard  Foote 

Where  the  Power  Comes  from 14 

By  E.  J.  Felix 

A  Distortionless  Audio  Amplifier .15 

By  E.  R.  Pfaff 

An  Improved  Slide  Wire  Bridge 17 

By  H.  Frank  Hopkins 

Electricity — the  Life  of  the  World 19 

By  Frank  D.  Pearne 

A  War  Against  Radio  Fading.... : 21 

By  S.  R.  Winters 

Experiments  with  a  Box  Kite  Aerial 23 

More  Super  Stations  are  Coming 24 

RADIO  AGE  "What  the  Broadcasters  are  Doing" 
Studio-Land  Feature  Section 25-32 

RADIO  AGE  Blueprint  Section — Dual  and  Single 

Controls..... 33-40 

By  John  B.  Rathbun 

Pickups  and  Hookups  by  Our  Readers. ...43-44-46-48 

Corrected  List  of  Broadcasting  Stations ,.66—68-70 


Radio  Age  is  published  monthly  by  RADIO  AGE,   Inc. 
Member:      Audit  Bureau  of  Circulations. 


Publication    Office,    Mount    Morris,    111. 

Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500    N.     Dearborn    Street,     Chicago,     111. 


Frederick  A.  Smith,  Editor 
Frank  D.  Pearne,   Technical  Editor 
M.   B.   Smith,  Business  Manager 


Advertising    Director 
HARRY  A.  ACKERBURG 

500  N.  Dearborn  St.,  Chicago,  III. 


Eastern     Representative 
DAVIDSON  &  HEVEY,   17   West  42nd  St.,   New   York   City 

Pacific    Coast   Representative 

V.   M.   DEPUTY  &  ASSOCIATES,  515  F.   W.    Braun   Bldg., 

Los  Angeles,   Cal. 

Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 

preceding  date  of  issue 

Vol.  4,  No.  10.     Issued  monthly.    Subscription  price  S2.50  a  year.    October.  1925. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris,  Illinois,  under  the 

Act  of  March  3,   1879. 

Oopwioht,  1925,  by  RADIO  AOE.  Inc. 


A  Chat  With 
the  Editor 

BIRDS  in  our  temperate  zones 
are  breaking  up  housekeeping 
and  preparing  for  their  an- 
nual flight  southward.  Hollyhocks 
are  flamboyant  along  the  garden 
walls,  like  glowing,  dying  embers. 
There  is  a  flaw  of  wind  at  sunset 
which  breathes  cool  oxygen  into 
fragrant  bonfires.  Soon  the  frost 
will  be  on  the  pumpkin  and  the 
maples  will  be  ablaze. 

Long  evenings  are  coming,  when 
the  fireplace  will  call  again  and 
there  will  be  mulling  cider  and 
beckoning  book  shelves. 

And  radio. 

That  is  what  we  were  coming  to. 
What  joy  of  listening  this  fall  and 
winter!  More  powerful  stations, 
better  broadcasting  technique,  im- 
proved programs,  superior  receiving 
apparatus.  It  has  been  the  busiest 
of  summers  on  the  air  and  it  is 
to  be  an  epochal  1925-1926  season. 
The  radio  industry  has  found 
itself.  Radio  listeners  have  thrust 
aside  the  doubt  and  inexperience 
of  another  day.  The  listening 
millions  know  exactly  what  they 
want  and  how  to  get  it. 

This  magazine  of  ours  has  been 
on  the  sentinel  line  watching  four 
such  seasons  of  good  reception 
send  forward  their  outposts  to 
prepare  for  a  new  drive  against 
dull  care  in  radio  time.  Our 
modest  sixteen-page  pamphlet  in 
the  early  spring  of  1922,  in  keep- 
ing step  with  the  march  of  radio, 
has  moved  forward  to  an  enviable 
position  among  publications. 

We  believe  you  will  like  this 
October  number  of  RADIO  AGE. 
We  assure  you  that  it  is  our  sole 
aim  to  make  each  succeeding 
number  more  helpful  and  more 
interesting.  Judging  from  the 
public's  generous  support,  we  have 
not  labored  in  vain.  We  hope 
the  magazine  will  be  your  com- 
panion these  long  evenings  to 
come  and  that  it  will  continue  to 
be  a  constructive  factor  in  the 
magnificent  destiny  which  awaits 
the  most  popular  of  all  sciences. 

Editor  of  Radio  Age. 


RADIO  AGE  for  October,  142: 


The  Magazine  of  the  Hour         3 


EVEREADY  HOUR 
EVERY   TUESDAY  AT  9  P.M. 

Eastern  Standard  Time 
For    real    radio   enjoyment,    tune    in    the 


"Eveready     Group.' 
stations — 
WEAF    New  York 


WJAR 

WEEI 

WFI 

WGR 

WCAE 


idence 
Boston 
Plriladelpliii 
Buffalo 
Pittsburgh 


Broadcast     thn 


WSAI        Cincinnati 
WWJ        Detroit 

WOCO  {  I^T1'8 
WOO        Davenport 
WCTS      Worcester 


t-GNTT'OR 

&Ry  cist* 
-radio,'io'nition/| 

ll-..  AND  ALU         ,c  i 

;  °ENERAL  PURP»St 

INSPECTED 

TESTED 
RELIABLE 

9    "WlOMAl  CARBOH  <*>** 


Tffff 

ft# 

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^"J'^pt       «s 

ECONOMY 

No  ONE  size  or  type  of  battery  can  be 
economical  on  every  type  of  receiving 
set.  That's  why  Eveready  Radio  Bat- 
teries are  made  in  different  sizes  and 
types — so  that  every  radio  user  can 
enjoy  the  economy  that  is  to  be  had  by 
fitting  exactly  the  right  Eveready  Bat- 
tery to  his  receiver.  For  owners  of 
sets  with  five,  six,  eight  or  more  tubes, 
and  power  amplifiers,  there  is  the  extra- 
large,  powerful  and  unusually  long-last- 
ing Eveready  "B"  Battery  No.  770. 
There  is  an  Eveready  dealer  nearby. 

Manufactured  and  guaranteed  by 

NATIONAL  CARBON  COMPANY,  Inc. 
New  York  San  Francisco 

Canadian  National  Carbon  Co.,  Limited,  Toronto.  Cnlario 

EVEREADY 

Radio  Batteries 


No.  766 
IVA-volt 

targe 

Horizontal 

Price 

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fl«*\ 


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$     Teatsd  #&&  Approved  &f  RADIO  AGS     $ 


RADIO  AGE  for  October,  i925 


7"he  Magazine  of  the  Hour 


HEREWITH  are  some  facts  about  the 
radio  gyps.  A  gyp  is  a  price-cutting 
sharp  shooter  who  fires  broadsides  of 
sensational  advertising  at  the  radio  public, 
offering  a  standard  product  at  less  than  the 
regular  retail  price.  When  a  customer  is  at- 
tracted to  the  gyp's  store  by  such  advertising, 
the  customer  finds  that  the  gyp  has  sold  out  his 
advertised  line  and  proposes  to  sell  the 
customer  something  else,  equally  as  attractive 
in  character  or  price.  Or  the  gyp  may  sell  him 
the  standard  product  advertised,  at  the  same 
time  neglecting  to  inform  the  customer  that  it 
is  an  obsolete  model  or  type,  and  is  worth  far 
less  than  the  amount,  that  even  the  gyp  is 
charging  for  it. 

Your  gyp  will  announce  in  his  advertisement 
that  he  has  500  Excella  Loud  Speakers  for  sale 
at  one  half  the  regular  price.  Investigation 
will  show  that  he  actually  has  perhaps  a  dozen 
Excella  Loud  Speakers  for  sale.  He  probably 
has  had  a  lot  of  trouble  in  getting  his  hands  on 
that  many.  But  he  announces  a  large  stock 
so  that  customers  will  come  to  him  with  con- 
fidence that  they  will  be  able  to  get  the 
Excella,  no  matter  though  they  may  arrive 
several  hours  after  the  doors  open  on  the 
"great  sale."  Failing  to  get  the  Excella,  the 
customer  looks  around.  Probably  he  buys 
something  else.  He  has  been  confidenced  into 
the  store  and  there  are  plenty  of  high  pressure 
clerks  in  the  place  to  see  that  he  does  not  get 
out  before  he  is  sold. 

Gyps  are  not  peculiar  to  the  radio  business. 
They  have  been  blow-torching  their  way  into 
legitimate  lines  of  trade  ever  since  the  time  of 
Tubal  Cain.  They  come  and  go  like  the  oily 
gentleman  who  manipulates  the  three  shells 
and  the  pea  at  county  fairs.  They  rent  cheap 
store  locations  and  decorate  their  windows 
with  enough  astonishing  price  propaganda  to 
make  even  a  wary  man  stop  and  look.  They 
are  not  welcomed  into  chambers  of  commerce, 
business  clubs  or  dealers'  associations.  Much 
of  the  merchandise  that  is  actually  what  they 
represent  it  to  be  is  obtained  by  them  through 
secret  sources.  It  bears  the  finger  prints  of 
unethical  business. 

One  might  suspect  that  after  a  few  lessons 
the  public  would  become  educated  to  such  an 


extent  that  the  gyp  would  have  to  go  out  of 
business.  Not  so.  Barnum  said  there  was  one 
sucker  born  every  minute  and  one  time  or 
another  each  one  of  them  lines  up  at  the 
counter  of  the  gyp.  The  best  that  can  be  done 
for  the  situation  is  a  continuous  presentation 
of  the  facts,  showing  the  advantage  in  dealing 
with  radio  merchandisers  who  buy  honestly, 
advertise  frankly  and  sell  fairly. 

The  radio  experimenter  or  complete  set  buyer 
may  establish  himself  in  a  safe  policy  by  adopt- 
ing a  rule  that  he  will  buy  only  from  those 
whose  advertisements  appear  in  reputable 
periodicals.  He  may  be  sure  that  if  the  period- 
ical is  of  good  character  and  is  building  for  a 
long  pull,  its  publishers  are  bound  to  carefully 
scrutinize  the  advertisements  as  well  as  the 
editorial  material  which  is  submitted  for  pub- 
lication. 

At  the  same  time,  manufacturers  and  dealers 
necessarily  use  care  in  the  selection  of  the 
periodicals  in  which  their  advertising  appears. 
What  would  you,  as  one  of  the  buyers  who  are 
turning  $400,000,000  into  the  coffers  of  the 
radio  industry  this  year,  think  of  the  advertiser 
who  would  permit  his  selling  message  to  appear- 
in  a  magazine  which,  for  example,  was  notori- 
ously competing  with  its  own  advertisers  by 
establishing  manufacturing  or  retailing  enter- 
prises and  publishing  advertisements  of  those 
enterprises  under  names  which  attempted  to 
conceal  the  magazine's  connection  with  the 
advertiser?  Or  what  would  you  think  of  the 
sagacity  of  a  manufacturer  who  would  advertise 
his  products  in  a  magazine,  which  in  a  single 
issue  wou'.d  print  page  after  page  of  advertis- 
ing announcing  cut  prices  on  standard  products 
which  established  and  reputable  manufactur- 
ers were  advertising  in  the  same  magazine  at 
higher,  though  perfectly  fair  and  reasonable; 
prices?  What  would  you  think  of  a  manu- 
facturer who  permitted  himself  to  be  tempted! 
away  from  reputable,  honest-dealing  magazines; 
by  the  gyp  lure  of  a  publisher  who  slashed 
advertising  rates  for  certain  accounts  and  mia- 
represented  circulation  figures  in  order  to  get 
the  customer  in?  Sagacious  advertisers  do  not 
fall  into  such  traps.  Buyers  of  radio  equip- 
ment may  profit  by  their  example. 


RADIO  ACE  for  October,  1025 


The  Magazine  of  the  Hour 


Radio  drafted  Bahelite 

so  all  could  listen-in 


To  make  available  for  everyone,  everywhere, 
the  marvel  of  radio  reception,  radio  engineers 
required  an  insulating  material  possessing  a 
unique  combination  of  properties. 

Bakelite  alone  met  the  need.  It  combines 
high  insulation  value  with  strength  and  light 
weight.  It  is  easily  formed  into  the  many 
shapes  required  and  will  not  warp,  shrink 
nor  swell.  It  will  not  absorb  moisture  and  is 
unaffected  by  extremes  of  heat  and  cold. 

All  of  these  properties  and  the  beautiful 
color  and  finish  of  Bakelite  are  permanent — 
unaffected  by  time,  use  or  climate.  So 
"Radio  drafted  Bakelite,"  and  today  it  is 
used  by  over  95%  of  radio  set  and  parts 
manufacturers. 

Make  sure  that  the  radio  set  or  parts  that  you 
buy  are  Bakelite  insulated,  for  good  insula- 
tion is  essential  to  clear  reception. 

Write  for  Booklet  31 

BAKELITE    CORPORATION 

247  Park  Avenue,  New  York,  N.  Y. 
Chicago  Office:  636  West  22d  Street 


* 


Bakelite  is  an  exclusive 
trade  mark  and  can  be 
used  only  on  products 
made  from  materials 
manufactured  by  the 
Bakelite  Corporation. 
It  is  the  only  material 
which  may  bear  this 
famous  mark  of  excel- 
lence. 


BAKELITE 


BAKELITE 

is  the  registered  trade 
mark  for  the  phenol 
resin  product  manu- 
factured under  pat- 
ents owned  by  the 
Bakelite  Corporation. 


THE    MATERIAL    OF  A  THOUSAND    USES 

*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  ACE  for  October,  1925 


The  Magazine  of  the  Hour 


6.W)EMGh 


WHAT  is  this  radio  service  which 
we  claim  is  so  necessary? 

Do  you  drive  a  car? 

Do  you  ever  have  little  things  go 
wrong  with  it? 

You  have  become  so  used  to  minor 
troubles  that  you  don't  condemn  the 
car  on  which  they  occasionally  occur. 

No— 

You  go  right  to  a  service  man — a 
man  who  knows  your  make  of  car. 
You  don't  go  to  a  handy  man  who 
claims  he  can  fix  any  car. 

That  s  automobile  service,  and  is  one 
of  the  main  reasons  for  the  auto  being 
the  success  it  is  today. 

The  same  service  condition  exists  in 
radio — the  only  difference  being  that 
people  don't  yet  understand  it. 

The  radio  instrument  which  never 
requires  service  has  never  been  built 
■ — it  never  will  be. 

Like  automobile  manufacturers,  the 
better  radio  manufacturers  do  all 
within  their  power  to  make  their  in- 
struments mechanically  perfect.  Nev- 
ertheless, like  the  auto,  little  things 
will  sometimes  go  wrong — they  are 
serious  to  the  radio  owner  but  very 
simple  to  a  factory  trained  service  man. 


Aether  you  smile  or  cuss 
depends  upon  the  service 
behind  your  Radios 


The  handy  man  who  can  fix  any 
radio  simply  experiments  until  he 
locates  the  trouble — such  a  method 
was  disastrous  to  the  auto  in  former 
days — it  is  disastrous  and  expensive 
in  radio  today.  It  is  not  sound. 

Ozarka  instruments  are  sold  only  by 
Ozarka  factory  representatives,  men 
who  are  factory  trained  in  sales  and 
service,  men  who  sell  no  other  radios 
but  Ozarka. 

These  men  don't  pretend  to  know 
all  about  radio  but  they  do  know  all 
there  is  to  know  about  Ozarka — isn't 
that  the  kind  of  radio  service  you  want? 

Ozarka  instruments  are  sold  under 
a  very  definite  plan.  An  Ozarka  repre- 
sentative will  gladly  set  up  an  Oza.ka 
in  your  home — he  won't  tune  it — he 
won't  tell  you  what  it  will  do — you 
must  operate  yourself.  If  the  results 
you  receive  by  your  own  operating 
won't  convince  you  that  the  Ozarka 
gives  you  the  distance,  volume,  selec- 
tivity, tone  and  ease  of  tuning  that 
you  demand  then  don't  buy  it. 

Ozarka  instruments  are  built  to  sell 
themselves  but  no  Ozarka  is  sold  with- 
out factory-trained  service  behind  it. 


Openings  for  a  Few 
More  OZARKA 

Factory 
Representatives 

OZARKA  Incorporated,  is  now  entering 
its  4th  year.  From  a  beginning  with  one 
engineer,  one  stenographer,  one  sales- 
man-our present  president,  theOzarka organ- 
ization has  grown  to  over  3, 1 00  people. There 
must  be  some  good  reason  for  this  growth. 

Ozarka  instruments  have  made  good — they  have 
more  than  met  competition.  Ozarka  representa- 
tives have  made  good  not  only  because  Ozarka 
instruments  were  right,  but  because  they  have 
been  willing  to  learn  what  Ozarka  engineers  were 
willing  and  capable  to  teach  them — Ozarka  un 
usual  salesmanship  and  Ozarka  service. 

There  are  still  openings  for  the  right  men  in  this 
organization — men  who  believe  in  the  future  of 
radio — men  who  are  tired  of  working  for  some  one 
else — men  who  want  a  business  of  their  own.  Prove 
yourself  by  sales  and  willingness  to  learn  and 
exclusive  territory  will  be  given  you.  The  man  we 
want  has  lived  in  his  community  for  some  time.  He 
has  the  respect  of  his  fellow  men  because  he  has 
never  "put  anything  over"  just  to  make  money.  He 
may  not  have  much  money,  but  he  is  not  broke  and 
is,    at    least,    able    to    purchase    one    demonstrating 

SendforFREEBook 

dio  offers  a  wonderful  opportunity  to  men  who 

filling  to  start  at  the  bottom  and  build.  You 

t    know    salesmanship,    but  will  you  learn 

:  will  gladly  teach  you?  You  may  not  know 

.  but  we  can  and  will  teach  you  if  you  will  do 

part.  With  such  knowledge  and  willingness  to 

.  it  doesn't  seem  possible  that  you  cannot  make 

Sign  the  coupon  below,  don't  fail  to  give  the 

of    your  county.    Better   still    write  a  letter. 

s  about    yourself   and   attach   the  coupon.    If 

:sted  in  our   salesman's  plan  ask  for   "Ozarka 

No.    100." 


Ra 
are  \ 
need 
what 
radi 
you; 
work 
good 

tell"! 


//Vft)RPORKTtf> 


122  Austin  Avenue  A 
Chicago*  Illinois 


Gentlemen:  Without  obligation  send  book  "Ozarka  Instru- 
ments No.  200"  and  name  of  Ozarka  representative. 

10-25- 122  A 
Name 

Address City 

County State 


Gentlemen:  I  am  greatly  interested  in  the  FREE  book  "The 
Ozarka  Plan"  whereby  I  can  sell  your  radio  instruments. 

10-25-  122A 
Name : 


You'll  Know  the  Man 
Behind  This  Button! 


Address City. 

County State . . . 


*     TttUd  and  Approved  bf  RADIO  AG«     * 


SEP28I925@C1B668175 

RADIO  AGE  jot  October,  1925 


The  Magazine  of  the  Hour 
IBB 


JSq  Magazine  (fthe  Hour 


M.  B.  Smith 

Rutiness  Manager 


A   Monthly    Publication 

Devoted  to  Practical 

Radio 


Frederick  A.  Smith 

Editor 


I 


Handling  the  Radio  Stages  with 

AUTO-TRANSFORMER   Coupling 


WHILE  there  are  a  number  of 
different  methods  available  for 
coupling  the  various  radio  stages, 
yet  the  transformer  method  of  coupling 
has  been  almost  universally  adopted  for 
radio  frequency  receiving  sets.  This 
applies  to  all  types  of  receivers  in  which 
radio  frequency  amplification  is  used, 
super-heterodynes  as  well  as  reflex 
circuits  and  plain  five  tube  sets  of  the 
popular  "dyne"  order.  At  one  time, 
tuned  impedance  coupling  by  means  of 
variometers  or  else  condenser  tuned  air- 
core  impedances,  seemed  to  be  gaining 
in  popular  approval,  but  when  the  neu- 
trodyne  was  introduced,  the  impedance 
system  received  a  set-back  from  which 
it  has  not  yet  recovered.  Resistance 
coupling,  after  the  manner  of  resistance 
coupling  the  audio  frequency  stages,  was 
only  efficiently  applicable  to  long  wave 
reception,  but  even  then,  the  resistor 
type  coupler  was  seldom  encountered, 
even  on  the  super-heterodyne,  where  it  is 
at  its  best. 

All  modern  air-core  transformers  are 
essentially  the  same,  no  matter  how  they 
may  differ  in  the  details  of  the  windings 
or  core.  They  all  have  a  primary  coil 
that  is  electrically  isolated  from  a 
secondary  coil  with  a  magnetic  coupling 
between  the  two 
circuits.  The  plate 
current  of  the  first 
tube  in  passing 
through  the  pri- 
mary coil  of  the 
condenser  creates 
a  magnetic  field 
which  in  turn  in- 
duces a  current  in 
the  secondary  coil. 
As  the  turn  ratio 
between  the  coils  is 
generally  greater 
than  unity,  the 
potential  estab- 
lished at  the 
terminals  of  the 
secondary,  and 
hence  at  the  grid 
of  the  following 
tube  to  which  they 
are  connected,  is 
greater   than    the 


B;y  ROSCOE  BVNDY 


Copyriglii    li'2."- 


Comparing  the  Many 
Methods   of   Coupling 


plate  potential  and  hence  greater  amplifi- 
cation results  from  the  increased  volt- 
age. The  transformer  affords  a  simple 
means  of  increasing  the  potential  at  the 
grid  of  the  tube,  and  hence  the  amplifica- 
tion, but  it  has  other  characteristics 
which  are  not  so  welcome — the  tendency 
toward  the  establishment  of  free  oscilla- 
tions for  one  thing. 

Capacity  Coupling 

NO  matter  how  carefully  the  trans- 
former may  be  designed  and  con- 
structed, there  is  always  a  certain  degree 
of  capacity  coupling  between  the  primary 
and  secondary  coils  which  causes  trouble, 
and  reduces  the  electrical  efficiency  below 
that  which  would  ordinarily  be  expected 
from  the  coil.  In  the  case  of  tuned  radio 
frequency   transformers,   the  inter-wind- 


ing capacity  seriously  affects  the  selectivi- 
ty and  always  has  a  strong  tendency 
toward  setting  up  free  oscillations  because 
of  the  low  resistance  of  the  winding.  An 
electro-static  transfer  takes  place  be- 
tween the  two  coils  regardless  of  the 
tuning  condenser  adjustment;  hence  the 
selectivity  is  not  all  that  could  be  de- 
sired. Signal  strength  is  reduced  when 
the  coupling  between  coils  is  reduced,  so 
there  is  a  decided  limit  to  the  practical 
utilization  of  the  incoming  waves. 

With  the  untuned  or  "aperiodic"  trans- 
former there  is  less  tendency  toward 
uncontrollable  oscillations  owing  to  the 
much  greater  resistance,  but  with  such 
transformers  there  is  no  selectivity  and 
a  very  great  deal  of  electrostatic  coupling 
which  reduces  the  effectiveness  of  the 
coils.  As  such  transformers  are  designed 
primarily  with  the  idea  of  obtaining  uni- 
form amplification  over  the  entire  broad- 
casting wavelength  without  tuning,  the 
selectivity  of  the  circuit  must  depend 
entirely  upon  the  antenna  tuning  system 
or  upon  auxiliary  tuned  stages  which  may 
be  introduced.  They  cannot  be  "peaked" 
on  a  certain  definite  wave;  hence  the  am- 
plification is  never  so  great  as  with  the 
tuned  secondary  transformers.  The  iron 
core  type  of  aperiodic  radio  frequency 
transforme  r 
has  a  higher 
amplification  than 
the  air  core,  as  a 
rule,  and  the  wave- 
band covered  with 
uniform  amplifica- 
tion is  greater,  but 
still  the  type  has 
other  undesirable 
characteristics. 

Impedance 
coupling,  both 
tuned  and  aperiod- 
ic, generally  gives 
a  lower  amplifica- 
tion  than  the 
transformer,  but  in 
certain  other  re- 
spects it  is  the 
superior  of  the 
transformer  type. 
It  is  easier  to  tune, 
is  not  quitesocriti- 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


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cal  on  the  controls  as  the  transformer  type, 
and  is  less  likely  to  cause  free  oscillations 
in  the  radio  frequency  circuit.  However, 
being  a  single  circuit  proposition  with  no 
means  of  controlling  the  coupling,  the 
tuned  impedance  type  of  receiver  is 
rarely  so  selective  as  the  tuned  air-core 
transformer  unless  unusual  pains  are 
taken  in  the  construction  of  the  coils 
and  in  the  arrangement  of  the  circuit. 
Again,  there  is  some  loss  of  plate  current 
through  the  inductance  to  the  "B" 
battery,  and  the  ratio  is  never  much 
greater  than  unity,  so  that  the  voltages 
impressed  on  the  following  tube  grid 
are   rather  low. 

In  Fig.  1  is  a  typical  aperiodic  trans- 
former coupling,  where  the  output  of  the 
tube  (Tl)  is  transferred  to  the  grid  of 
tube  (T2)  through  the  air-core  radio  fre- 
quency transformer  (RF-2);  Plate  cur- 
rent from  (Tl)  passes  from  the  "B" 
battery  through  the  primary  coil  (P) 
on  its  way  to  the  plate,  hence  all  pulsa- 
tions in  the  coil  (P)  are  inductively 
transferred  to  the  secondary  coil  (S)  by 
magnetic  linkage.  A  comparatively  high 
potential  is  developed  at  the  end  of  the 
secondary  coil  (G),  and  this  acts  on  the 
tube  (T2)  to  produce  greater  amplifica- 
tion. Tube  (Tl)  receives  its  energy  from 
a  tube  connected  to  the  input  (Primary) 
of  transformer  (RF-1)  and  the  same 
system  is  carried  out  with  any  desired 
number  of  "radio  stages." 

In  this  sort  of  transformer,  the  wind- 
ings are  so  proportioned  that  a  fairly 
uniform  coupling  is  had  over  a  fairly 
wide  range  of  wavelengths,  say  from  200 
meters  to  550  meters.  The  coils  are 
wound  with  fine  wire  and  have  a  con- 
siderable resistance,  which  damps  down 
free  oscillations  but  which  equally  causes 
comparatively  high  ohmic  losses  and  re- 
duced amplification. 

Tuned  R.  F.  Transformers 
T3  Y  tuning  the  secondary  coil  to  wave- 
*-*  length  by  means  of  variable  con- 
densers as  in  Fig.  2,  the  transformers  can 
be  accurately  "peaked"  at  the  desired 
wavelength  so  that  the  maximum  ampli- 
fication is  secured  on  any  wavelength 
within  the  range  of  the  condensers.  The 
variable  condensers  (CI)  and  (C2)  are 
connected  directly  across  the  secondary 
coils  (S)  of  the  transformers  (RF-1)  and 


(RF-2)  in  the  familiar  fashion,  but  the 
primary  coils  (P)  are  not  separately  tun- 
ed and  are  therefore  known  as  "aperiodic 
primaries."  As  few  as  five  or  six  turns 
are  often  used  for  the  primary  coils  (P) 
which  brings  their  natural  period  far 
below  that  of  any  ordinary  broadcasting 
wave  and  therefore  the  grid  and  plate 
circuits  are  not  so  likely  to  be  tuned  into 
resonance  and  self-oscillation  as  would 
be  the  case  with  a  greater  number  of 
turns.  The  number  of  turns  and  length 
of  wire  on  the  secondary  coils  are  determin- 
ed by  the  wavelength  band  and  the  size 
of  the  variable  condensers  (C1-C2),  and 
the  turn  ratio  between  the  primary  and 
secondary  varies  from  6-to-l  to  11-to-l 
in  commercial  types  of  coils. 

Owing  to  the  small  amount  of  wire  on 
the  tuned  radio  frequency  transformers, 
the  resistance  is  very  low  and  the 
efficiency  is  correspondingly  high.  By 
properly  adjusting  the  distance  between 
the  primary  and  secondary,  thus  main- 
taining a  proper  magnetic  coupling,  the 
coils  can  be  made  very  selective  provid- 
ing that  the  electrostatic  coupling  is  kept 
at  a  minimum  at  the  same  time.  By 
having  a  number  of  successive  tuned 
radio  stages  of  this  type,  the  total  selec- 
tivity can  be  made  to  reach  a  high  degree, 
for  each  successive  stage  makes  it  possible 
to  reduce  the  interference  waves  passed 
by  the  preceding  transformer  until  un- 
desired  stations  are  completely  elimi- 
nated. 


Tuned  impedance  coupling  is  really  the 
simplest  type,  although  it  does  not  give 
quite  the  amplification  given  by  the  trans- 
former. A  detail  is  shown  by  Fig.  3 
where  the  three  tubes  (T1-T2-T3)  are 
i  mpedance  tuned  by  the  fixed  inductances 
(L1-L2)  and  the  variable  condensers 
(C1-C2)  connected  across  the  ends  of  the 
inductance  coils.  Increasing  the  capacity 
of  the  condensers  increases  the  induct- 
ance and  wavelength  of  the  coils  so 
that  they  can  be  peaked  on  a  given 
wavelength  just  as  with  the  tuned  radio 
frequency  transformers.  The  positive 
(+B)  current  passes  from  the  "B" 
battery  to  the  plates  of  the  tubes  through 
the  inductances,  and  the  inductances  are 
tuned  so  that  the  plate  output  of  pulsat- 
ing current  cannot  short  circuit  and 
pass  back  to  the  battery.  The  con- 
densers are  adjusted  until  the  inductance 
is  just  sufficient  to  choke  back  the  radio 
frequency  current  at  the  given  wave- 
length so  that  it  cannot  pass  through 
the  "B"  battery  circuit,  and  at  this 
point  a  maximum  difference  of  potential 
is  established  across  the  ends  of  the  coils 
so  that  the  greatest  possible  potential 
is  brought  on  the  grid  of  the  following 
tube  through  the  fixed  stopping  con- 
densers   (K1-K2). 

Stopping  condensers  (Kl)  and  (K2) 
must  be  provided  between  the  plate 
and  the  grid  of  the  following  tube  to 
prevent  the  "B"  battery  current  from 
reaching  the  grid  and  giving  it  a  positive 
bias.  If  the  positive  "B"  were  to  act 
on  the  tube,  it  would  be  paralyzed  and 
rendered  useless  as  an  amplifier,  for  a 
negative  potential  is  necessary  on  the 
grid  for  amplification.  However,  the 
capacity  of  the  fixed  condensers  is  great 
enough  to  pass  the  radio  frequency  cur- 
rent freely  from  plate  to  grid  so  that 
coupling  and  amplification  takes  place. 
Radio  frequency  oscillating  current  can 
pass  directly  from  the  plate  to  the  grid 
of  the  following  tube  but  the  direct 
battery  current  cannot  pass. 

Adjusting  the  Leaks 
\S  the  grid  requires  a  negative  "bias" 
-^*-  or  a  continuous  negative  charge  for 
amplification,  the  high  resistance  grid 
leaks  (Rl)  and  (R2)  are  connected  to 
the  grid  side  of  the  coupling  condensers 
with  their  outer  ends  connected  to  the 
(-A)  wire  of  the  filament  battery.  A 
small  amount  of  current  passes  through 


RADIO  AGE /or  October,  1925 


The  Magazine  of  the  Hour 


the  leaks  to  the  grid  from  the  negative 
pole  of  the  "A"  battery,  and  the  required 
amount  can  be  obtained  by  adjusting  the 
leaks  until  the  proper  bias  is  found  by 
experiment.  It  should  be  noted  that  the 
leaks  are  an  indispensable  proposition 
in  this  sort  of  circuit  and  that  they  must 
be  carefully  fitted  to  the  tubes  for  maxi- 
mum results.  The  stopping  condensers 
(Kl)  and  (K2)  are  not  critical. 

Instead  of  the  simple  tuned  inductances 
shown,  variometers  can  be  employed, 
and  as  a  rule  the  variometers  are  more 
efficient  than  the  present  scheme  although 
they  have  practical  disadvantages.  The 
introduction  of  variable  condensers  causes 
losses  which  are  avoided  by  the  pure 
inductance  of  the  variometers. 

A  coupling  of  this  sort  is  less  critical 
than  a  transformer  coupling,  that  is,  the 
peak  of  amplification  is  not  produced 
within  a  fractional  part  of  a  dial  division, 
and  for  this  reason,  squealing  is  not  so 
often  experienced  with  the  tuned  induc- 
tances as  with  transformers.  However, 
it  is  less  selective  per  stage  than  the 
transformer  coupling,  and  even  with  its 
purer,  cleaner  tone  it  is  often  supplanted 
by  the  transformer  for  this  reason.  The 
impedance  gives  a  wonderfully  pure  tone 
when  properly  constructed  with  practi- 
cally no  distortion  or  noise,  and  this  is 
probably  due  to  the  checking  of  audio 
frequency  currents  by  the  stop  conden- 
sers in  the  grid  lines. 

Many  experiments  have  been  made  by 
the  writer  in  the  attempt  to  combine  the 
advantages  of  the  transformer  and  tuned 
impedance,  and  out  of  these  experiments 
the  "auto-transformer"  type  of  induct- 
ance has  proved  the  most  successful. 
It  avoids  the  noise  and  critical  adjust- 
ments so  often  in  evidence  with  straight 
transformer  coupling  and  at  the  same 
time,  the  degree  of  amplification  is  much 
better  than  with  the  tuned  impedance 
type.  So  far  as  selectivity  and  distance 
are  concerned,  the  auto-transformer  coup- 
ling has  been  found  eminently  satis- 
factory in  the  vicinity  of  Chicago  where 
interference  from  local  broadcasting  sta- 
tions is  at  a  maximum.  The  volume  is 
slightly  less  than  with  the  transformers 
but  the  tone  is  so  wonderfully  improved 
that  it  more  than  compensates  for  the 
lost  amplification. 

An  auto-trans- 
former consists  of 
a  single  continuous 
tapped  coil  which 
serves  both  as  a 
primary  and  sec- 
ondary. In  Fig.  4 
is  the  complete  coil 
(A-B)  tapped  at 
the  point  (t),  the 
latter  being  the  in- 
put for  the  plate 
current.  In  pass- 
ing from  (  +  B)  to 
(t)  through  a  small 
portion  of  the  coil, 
the  turns  in  the  dis- 
tance (m)  become 
the  virtual  pri- 
mary of  the  auto- 
transformer,  while 
the  total  length  (n) 
forms  the  second- 


ary although  all  parts  of  the  circuit  are 
electrically  connected.  Both  the  vir- 
tual primary  section  (m)  and  the  second- 
ary section  (n)  are  threaded  through  by 
the  same  magnetic  flux  and  are  magneti- 
cally as  well  as  electrically  coupled. 
Therefore,  with  a  given  ratio  of  turns 
between  (m)  and  (n),  we  can  correspond- 
ingly build  up  the  potential  at  (B)  just 
as  in  the  transformer  secondary  coil. 
The  voltage  between  the  ends  (a)  and 
(b)  is  now  much  higher  than  between 
the  primary  terminal  (m),  and  greater 
amplification  can  be  had  than  with  a 
simple  tuned  inductance.  The  coil  is 
tuned  by  the  variable  condenser  (CI). 
In  Fig.  5  we  have  a  detail  of  the  appli- 
cation of  the  auto-transformer  to  the 
receiving  set.  The  output  (plate  cur- 
rent) of  the  first  tube  (Tl)  passes 
through  the  virtual  primary  (P)  to  the 
battery  at  (  +  B).  The  position  of  the 
tap  point  (t)  determines  the  ratio  of  the 
primary     to     secondary     turns     or     the 


"ratio"  of  the  transformer.  The  total 
result  is  a  greatly  increased  potential 
in  the  grid  line  at  the  stopping  condenser 
(Kl)  that  gives  high  amplification  in  the 
second  tube  (T2).  As  before  explained, 
the  stopping  condenser  (Kl)  prevents 
the  "B"  battery  from  putting  a  positive 
bias  on  the  grid  of  tube  (T2). 

A  grid  leak  (Rl)  is  placed  on  the  grid 
side  of  the  stopping  condenser  (Kl),  and 
by  connecting  the  other  end  of  the  grid 
leak  to  the  negative  filament  line  (-A), 
a  negative  potential  can  be  established 
on  the  grid  of  (T2).  The  plate  output 
of  (T2)  is  then  led  through  the  tap  point 
(t)  of  the  second  auto-transformer  (L2), 
and  further  amplification  is  attained  in 
the  third  tube  by  the  same  method. 
The  variable  condenser  (CI)  is  used  to 
tune  the  system  to  wavelength  in  the 
usual  manner.  We  really  have  a  trans- 
former, but  it  is  a  special  form  of  trans- 
former that  performs  exceedingly  well 
in  regard  to  tone  and  freedom  from  self- 
oscillations. 

As  the  tubes  are  somewhat  critical  to 
the  resistance  of  the  leaks,  an  adjustable 
resistance  is  best  at  this  point  so  that  the 
resistance  can  be  just  right  for  the  indi- 
vidual tubes  with  maximum  volume. 
After  once  adjusted,  the  leaks  need  no 
further  care  until  the  tubes  are  changed 
or  replaced  by  new.  It  is  not  necessary 
to  mount  the  grid  leak  controls  on  the 
front  panel. 

Complete  Auto-Transformer  Circuit 

IT'IG.  6  shows  the  complete  circuit  for 
■'-  use  with  auto  transformers,  two 
stages  of  radio  frequency  amplification 
and  detector.  Audio  amplification  can 
be  added  to  the  output  as  with  any  other 
radio  frequency  set,  but  is  not  shown  here 
as  it  is  considered  desirable  to  concen- 
trate our  attention  upon  the  inductances 
and  other  details  of  the  radio  frequency 
stages.  After  the  previous  description 
it  should  not  be  difficult  to  understand 
the  principles  of  operation. 

It  should  be  particularly  noted  that 
the  two  radio  frequency  tubes  (Tl)  and 
(T2)  are  given  a  negative  bias  by  con- 
necting the  ends  of  the  leaks  (R)  to  the 
(-A)  line.  On  the  other  hand,  the  detec- 
tor' tube  (T3)  is  given  a  positive  (  +  ) 
bias  by  connecting  the  leak  (R3)  to  the 
positive  (+A)  side 
of  the  filament 
battery  line.  This 
change  in  biasing 
polarity  is  most 
important,  and  if 
it  is  not  observed, 
the  set  will  be  in- 
operative or  at 
least  greatly  weak- 
ened. All  of  the 
constants  given  for 
the  units  on  the 
drawing  will  be 
found  correct  for 
the  majority  of 
cases,  although 
there  is  consider- 
able development 
work  yet  to  be 
done  before  the 
circuit  reaches  its 
(Turn  the  page) 


10 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


-=■£ 


X 


|i|i|i|i|i|!|i|i|i|iH> 

B  + 


/ye.  6 


highest  efficiency.  It  is  a  brand  new  type 
so  far  as  I  am  aware,  and  promises 
much  with  further  experimental  work  in 
regard  to  details.  It  is  intended  as  a  sug- 
gestion for  the  more  experienced  fans 
who  find  pleasure  in  experimenting  with 
novel  circuit  combinations  and  is  not 
particularly  advised  for  the  beginner. 

The  total  number  of  turns  on  the  auto- 
transformer  from  end  to  end  of  the  coil 
will  be  from  55  to  60  on  a  three  inch 
tube.  Generally,  the  tap  point  (t)  for  the 
connection  of  the  plate  circuit  works 
out  best  at  8  turns  from  the  end,  but 
it  will  be  safest  to  provide  at  least  three 
taps  at  8,  12  and  15  turns  so  that  the 
optimum  ratio  can  be  easily  determined 


by  experimental  means.  With  55  turns 
total,  a  0.00035  mf.  variable  condenser 
connected  across  the  ends  of  the  coil  will 
tune  it  through  the  broadcast  range  of 
wavelengths.  As  explained  before,  the 
circuit  is  rather  critical  to  the  grid-leak 
value  and  for  this  reason  variable  resist- 
ances are  the  best.  The  approximate 
value  of  fixed  leaks  is  shown  on  the  draw- 
ing, and  with  the  tubes  used  in  the  ex- 
periments this  resistance  value  gave  very 
good  results. 

The  capacity  of  the  stopping  conden- 
sers is  not  critical  and  almost  any 
capacity  that  will  freely  pass  radio 
frequency  currents  will  be  satisfactory. 
Values  ranging  from  0.0005  mf.  to  0.005 


mf.  were  tried,  but  above  0.002  mf.  there 
did  not  seem  to  be  much  increase  notice- 
able. Below  0.001  mf.  there  was  some 
falling  off  in  volume,  but  not  a  great  deal 
of  loss.  The  ordinary  45  to  90  volts  can 
be  applied  to  the  grids  of  the  tubes, 
although  the  lower  voltage  probably 
brings  in  distance  better  than  the  90 
volts  which  gives  the  greatest  volume  on 
local  stations. 

If  more  radio  frequency  stages  are  de- 
sired, they  can  be  added  by  repeating 
the  auto-transformer  and  leak  arrange- 
ment shown  for  the  first  two  stages. 
Four  and  five  stages  have  been  used 
without  difficulty  in  the  way  of  critical 
tuning,  and  the  quality  was  little  affected 


U.    S.    Radio   Representatives 
Sail  for  Paris 

WASHINGTON.— America's  three  un- 
official observers  to  the  International 
Telegraph  Conference  at  Paris  sailed 
from  New  York  on  the  S.  S.  America 
last  month.  The  delegation  was  headed 
by  John  Beaver  White,  a  retired  engineer 
of  Philadelphia,  and  included  Honorable 
Wallace  H.  White,  Jr.,  Congressman  of 
Maine,  and  Maj.  Gen.  Charles  McK. 
Saltzman,    Chief    Army    Signal    Officer. 

Although  the  United  States  is  not  a 
party  to  the  International  Telegraph 
convention,  the  Senate  never  having 
acted  on  it,  it  is  understood,  its  represen- 
tatives will  be  seated  as  unofficial  dele- 
gates and  granted  all  privileges  except 
the  right  to  vote.  In  this  capacity  the 
U.  S.  delegation  will  present  the  views  of 
the  U.  S.  Government  and  probably  also 
the  attitude  of  the  private  interests  which 
own  and  operate  the  commercial  tele- 
graph, cable  and  radio  services,  as  to  the 
desirability  of  incorporating  the  field  of 
radio  in  the  international  regulations 
prescribed  by  the  telegraph  convention. 

For  the  past  month,  representatives  of 
the  several  government  departments  in- 
terested in  radio  have  met  daily  in  the 
State  Department.  This  body,  known  as 
the  Interdepartmental  Committee  on 
Electrical  Comm.,  has  discussed  the 
proposals  submitted  to  this  government 


some  time  ago  by  the  International 
Telegraph  Bureau  at  Berne,  together  with 
the  agenda  of  the  international  sessions 
which  opened  in  Paris  on  September  1st. 
One  of  the  many  suggestions  made  by  the 
European  Governments  is  that  the  sub- 
ject of  radio  be  considered  at  the  con- 
ference. To  this  it  is  believed  the  Ameri- 
can government  will  object,  in  view  of 
the  special  world  conference  on  radio  to 
be  held  in  Washington  in  the  near  future. 
At  least,  the  delegates  will  express  a  hope 
that  any  changes  made  in  the  present 
telegraph  convention,  will  be  such  as 
would  be  acceptable  to  the  radio  confer- 
ence when  it  meets  here.  Obviously,  it 
would  not  be  desirable  to  have  matters 
pertaining  to  radio  threshed  out  in  detail 
prior  to  the  regular  radio  sessions.  On 
the  other  hand,  assurance  is  given  by 
the  Berne  Bureau  that  only  the  inter- 
national radio  policy  with  its  commercial 
and  business  angles  would  be  included 
if  this  subject  is  injected  into  the  tele- 
graphic sessions  at  Paris.  That  is,  the 
technical  side  and  service  regulation 
affecting  wavelengths,  power,  schedules, 
etc.,  probably  will  not  be  considered. 
The  U.  S.  Interdepartmental  Committee 
has  analyzed  the  voluminous  report  from 
Berne,  to  see  how  it  affects  the  interest 
of  the  United  States,  where  all  communi- 
cation systems  are  privately  owned. 
It  has  filed  its  report  with  Secretary 
of  State,   Kellogg,  who,  it  is  understood 


has  prepared  letters  of  instructions  to 
the  American  delegates  as  to  this  govern- 
ment's policy.  This  policy  has  not  been 
released  by  the  State  Department,  and 
may  not  be  made  public,  but  it  is  said  to 
express  a  desire  on  the  part  of  the  Govern- 
ment and  the  private  commercial  radio 
interests,  that,  if  possible,  radio  be  kept 
out  of  the  general  telegraph  discussions 
and  that  this  subject  in  its  many  phases 
be  left  for  the  world  radio  conference. 

The  Chairman  of  the  Interdepartment- 
al committee,  Leland  Harrison  of  the 
State  Department,  has  not  attended  the 
sessions  here.  In  his  absence,  J.  B. 
White,  a  friend  of  Secretary  Hoover, 
has  acted  as  chairman  of  the  special 
committee  on  Paris  conference.  The 
personnel  of  the  committee  includes 
Maj.  Gen.  Saltzman,  and  Major  J.  O. 
Mauborgne  of  the  Signal  Corps;  Captain 
Ridley  McLean,  Director  of  Naval  Com- 
munications; Asst.  Secretary  of  Com- 
merce Stephen  Davis,  and  P.  E.  D.  Nagle 
and  W.  D.  Terrell  of  the  communications 
and  radio  sections  of  the  Commerce 
Department;  H.  C.  Moore  of  the  Ship- 
ping Board;  E.  M.  Webster  of  the 
Treasury,  and  W.  R.  Valance  and  W.  M. 
Greene  of  the  State  Department. 

Technical  aides  who  accompanied  the 
American  Delegation  included  W.  D. 
Terrell,  Chief  Supervisor  of  Radio  of  the 
Department  of  Commerce  and  Maj.  J.  O. 
Mauborgne,    of   the   Signal    Corps 


RADIO  AGE  for  October,  192 


Hie  Magazine  of  the  Hour 


Some  Facts  About  QUALITY 


11 


Loud 
Speaker 
Music 
Without 
Trouble- 
some 
Distortion 
Is  Now 
The  Big 
Problem  in 

Radio 
Reception 


A  simple  low  frequency 
reproducer      to      supple- 
ment the  regular  horn  type 
loud  speaker   may   be  built 
from  a  banjo-mandolin  and  a 
Baldwin  receiver  unit.      A    long 
pin  is  used  to  connect  the  armature 
to  the  mandolin  head. 


By  BRAIN ARD  FOOTE 


Expert 
Tells  How 

Use  of 

Two  Loud 

Speakers 

WillEnable 

Listener 

to  Receive 

Pure  High 

and  Low 

Notes 
Faultlessly 


THE  general  problem  in  connection 
with  entertainment  with  a  loud 
speaker  is,  briefly,  to  reproduce  music 
and  voice  just  as  it  sounds  in  the  broad- 
cast-station's studio.  This  resolves  itself 
at  once  into  three  separate  departments 
of  radio  reception,  as  follows: — 

1.  Faithful  detection 

2.  Undistorted  amplification 

3.  Clear  reproduction 

Thus  we  must  start  with  a  com- 
paratively weak  impulse,  in  itself  true 
to  the  original,  make  it  stronger  without 
accentuating  any  part  of  it  over  and 
above  the  rest,  and  then  employ  a  re- 
producing device  that  doesn't  render 
our  earlier  efforts  fruitless. 

If  we  attack  the  problem  of  undis- 
torted entertainment  with  a  clear  recog- 
nition of  the  various  portions  of  the 
radio  set  wherein  the  faults  are  likely  to 
be  situated,  we  are  in  a  better  position 
to  rectify  them.     Let's  try  it  in  this  way. 

The  Detector 

USUALLY,  the  reproduction  by  the 
detector  is  perfect.  Headphones 
are  plugged  into  the  detector  jack  by 
way  of  verification.  However,  trouble 
is  sometimes  met  because  of 

1.  Over-sharp  tuning. 

2.  Bad  grid  leak  and  grid  condenser. 
Over-sharpness  of  tuning  can   seldom 

be  found  with  multi-tube  sets  having 
three  tuned  circuits,  nor  indeed  with 
single  tube  sets  unless  regeneration  is  too 
prominent.  In  tuned  R.  F.  amplifiers 
that  are  on  the  verge  of  oscillation,  due 
to  inter-stage  feed-back  or  to  the  use  of 
primary  windings  that  are  too  large, 
the  sharpness  of  tuning  is  extremely 
pronounced.  The  "side-bands"  or  slight- 
ly different  frequencies  which  convey 
the    overtones    of    music    or    speech    are 


cut  off  thereby.  These  side-bands  are 
nothing  but  wavelengths  just  a  bit 
different  from  the  stated  wavelength 
of  the  station  and  are  directly  due  to 
the  fact  that  the  imposition  of  voice 
frequencies  on  the  carrier  wave  not  only 
has  a  modulation  effect  but  a  HETERO- 
DYNING effect  as  well. 

In  one-tube  sets,  the  quality  may  be 
ruined  in  the  same  way,  merely  by  turn- 
ing the  tickler  coil  a  little  too  close  to 
the  oscillation  point.  In  this  case, 
it's  a  question  of  operation,  however. 

If  the  grid  condenser  is  not  perfectly 
insulated,  interfering  noises  may  start 
in  it.  The  grid  leak,  even  more  often, 
is  responsible  for  hissing  and  sizzling 
sounds,  so  that  it  is  always  wise  to  test 
three  or  four  of  them,  as  well  as  two  or 
three  grid  condensers  to  get  a  good  com- 
bination. A  weak  station  should  be 
listened  to  during  this  process  and  the 
combination  yielding  the  quietest  opera- 
tion chosen. 

Outside  of  these  two  sources  of  trouble, 
and  assuming  a  good  tube  and  batteries, 
the  headphones  should  respond  with  good 
clear  music,  in  which  the  soprano's 
voice  is  sweet  and  pure  and  in  which  the 
low  thud  of  the  drums  and  the  bass 
chords  of  the  piano  come  through  with 
equal  effectiveness. 

Audio  Amplification 

PASSING  now  to  the  next  department 
of  our  research,  we  tackle  the  audio 
amplifier.  The  loud  speaker  is  left  dis- 
connected, but  otherwise  the  amplifier 
is  turned  on,  ready  to  work.  The  head- 
phones are  connected  across  the  pri- 
mary winding  of  the  first  audio  trans- 
former. Do  the  drums  and  piano  chords 
still  stand  out?  If  so,  that  stage  is 
operating    satisfactorily    and    the    trans- 


former handles  the  lower  frequencies 
quite  well.  However,  the  higher  notes 
will  be  slightly  more  pronounced  in  this 
stage.  If  there  is  any  sudden  crackling 
or  surging  of  the  volume,  something  is 
wrong  with  the  tube's  functioning.  Prob- 
ably a  "C"  battery  of  3  volts  is  needed 
in  that  stage  to  maintain  the  grid's 
potential  at  a  negative  value.  Usually, 
though,  the  first  stage  gives  a  fine 
account  of  itself. 

But  how  about  the  second  step? 
Place  the  headphones  there  and  turn 
down  the  volume  a  little  so  that  the 
phones  aren't  overloaded.  Now  it  will 
probably  be  found  that  the  lower  notes 
don't  come  through  so  well  and  that 
when  the  volume  is  boosted  a  little  the 
crashes  on  the  piano  are  blurred  and 
there  is  a  certain  fuzziness  about  it. 
Replacing  the  loud  speaker,  we  shall 
find  very  much  the  same  thing.  With 
full  volume,  the  loud  speaker  does  NOT 
reproduce  as  clearly  as  did  the  phones, 
although  it  will  do  so  if  it  is  connected 
to  the  first  stage  (the  volume  is  less, 
however).    What  is  wrong? 

1.  The  last  tube  is  overloaded  and 
hasn't  sufficient  undistorted  variation 
of  plate  current  to  operate  a  speaker. 

2.  The  audio  amplifier  omits  the  low 
notes. 

Resistance-Coupling 

The  latter  of  these  two  faults  found 
with  the  transformer-coupled  amplifier 
may  be  corrected  easily  by  the  use  of  an 
audio  amplifier  capable  of  amplifying 
all  moderate  frequencies  to  the  same 
extent.  The  audio  transformer  is  in- 
herently a  tuning  device.  We  know  that 
the  wavelength  is  equal  to  the  velocity 
of  the  radio  wave  divided  by  its  fre- 
quency.     Thus,  WJZ  operates  on  about 


12 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


.  Is 

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etiso 


6     o 

+-     - 
A      A 


I  fo  2  <»»p;. 


^G  e. 


Fig.    2 — To  prevent  overloading  of  the  last  audio  tube,  a  heavy  power  tube  may  be  em- 
ployed, or  as  an  alternative  nearly  as  good,  two  tubes  may  be  operated  in  parallel. 


659,000  cycles,  or  455  meters.  When 
we  come  to  the  voice  frequencies  of  100 
to  perhaps  5,000  cycles,  the  wavelength 
is  very  much  longer.  Suppose  the  musi- 
cal note  has  a  frequency  of  1000  cycles. 
Its  wavelength  then  is  300,000  meters! 
To  amplify  at  such  enormous  wave- 
lengths audio  transformers  have  many 
thousand  turns  of  wire.  Small  wire  is 
used  for  compactness  and  an  iron  core 
to  still  further  lower  the  range  and  to 
broaden  the  tuning.  Still,  the  trans- 
former is  a  tuned  device  and  just  like  a 
radio  frequency  transformer  except  that 
it  has  more  turns  of  wire  and  an  iron 
instead  of  an  air  core.  At  best,  then,  it 
cannot  amplify  all  frequencies  equally. 
It  has  a  "peak"  on  either  side  of  which 
the  amplification  falls  off. 

The  sort  of  audio  amplifier  that 
handles  all  audio  frequencies  impartially 
doesn't    depend    on    tuning.      It    uses   a 


resistance  and  functions  on  the  voltage 
drop  principle.  The  fact  that  a  resist- 
ance-coupled amplifier  operates  well  at 
a  very  wide  range  of  frequencies  is  proven 
by  its  use  in  the  super-heterodyne  re- 
ceiver as  the  long-wave  amplifier.  In 
such  a  case  it  is  amplifying  radio  fre- 
quency currents  of  perhaps  10,000 
cycles.  Yet  the  self-same  amplifier  will 
amplify  at  audio  frequency  when  such 
energy  is  fed  into  it! 

The  mechanical  and  electrical  draw- 
backs to  the  resistance-coupled  amplifier 
lie  in  the  necessity  for  using  135  to  150 
volts  of  "B"  battery  and  the  need  for 
one  more  tube  than  required  for  the 
transformer  amplifier.  However,  the 
individual  plate  current  is  much  less 
than  with  a  transformer  coupled  am- 
plifier, so  that  even  with  the  extra  tube 
and  extra  "B"  battery,  the  total  expense 
per  year  of  operation   is  less  than   with 


a  transformer  coupled  outfit.  The  coup- 
ling resistances  should  be  of  the  order 
of  100,000  ohms  (.1  megohm)  and  the 
grid  leaks  of  sufficiently  low  resistance 
to  allow  a  suitable  negative  bias  of  about 
3  volts  on  the  grids  without  causing 
too  much  loss  of  volume.  A  grid  leak 
resistance  of  about  2  megohms  for  the 
first  stage  of  resistance  coupling,  and 
1  megohm  for  the  second  and  third 
stages  each.  A  "C"  battery  is  very 
helpful  in  reducing  the  "B"  battery  cur- 
rent without  causing  any  loss  in  volume. 

Care  must  be  taken  with  such  an  ampli- 
fier to  use  a  lower  plate  voltage  for  the 
tube  in  which  the  loud  speaker  is  connec- 
ted. 90  volts  is  a  sufficient  potential  for 
the  last  stage  on  this  account.    See  Fig.  1. 

The  quality  of  amplification  may  be 
tested  with  headphones.  First  the 
phones  are  connected  across  the  GRID 
LEAK  of  the  first  amplifier.  The 
volume,  of  course,  is  very  low,  but  the 
quality  may  be  noted.  The  phones  are 
not  connected  across  the  coupling  re- 
sistance, for  the  tube  plate  voltage 
would  then  rise  greatly  and  the  detector 
probably  go  into  oscillation.  To  observe 
the  quality  on  the  first  stage  of  the 
resistance  amplifier,  the  phone  cords 
are  bridged  across  the  SECOND  grid 
leak.  Thus  the  nature  of  the  input  to 
each  successive  stage  may  be  listened  to 
and  criticized  for  tonal  characteristics. 
In  general,  these  will  be  above  reproach 
up  to  and  including  the  grid  leak  in  the  last 
stage.  The  loud  speaker  may  still  distort, 
however,  even  though  you  may  hear  the 
lower  notes  and  the  higher  notes  coming 
through  with  much  better  naturalness  than 
with  a  transformer-coupled  amplifier. 

Overloaded  Tube 

HENCE   trouble   No.    1   of  the  trans- 
former-coupled    amplifier     is     still 
met    in    the    resistance    amplifier — that 


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Circuit  for  a  three-stage  resistance-coupled  audio  amplifier  together  with  the  detector  connections,   showing  how  three  different 

plate  voltages  are  required- 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


13 


of  an  overloaded  tube.  A  single  201A 
or  301A  tube  does  NOT  have  sufficient 
variation  in  plate  current  to  actuate  a 
large  loud  speaker  properly.  Of  course, 
almost  all  sets  are  built  that  way,  but 
it  is  true,  nevertheless,  that  the  second 
audio  tube  is  receiving  variations  in 
grid  input  altogether  too  great  for  it  to 
handle.  The  grid  voltage  changes  NO 
LONGER  control  the  plate  current 
with  perfection. 

Therefore,  the  obvious  solution  to 
this  part  of  the  problem  lies  in  the  use 
of  a  heavier  tube  or  in  using  two  or 
three  "A"  tubes  in  parallel  to  gain  the 
desired  effect.  The  improvement  in 
tone  quality  found  in  this  way  is  aston- 
ishing. The  loud  speaker  talks  up  with 
crispness.  There's  no  "draggy"  effect 
as  the  tube  tries  to  recover  from  one 
shock  just  as  another  one  comes  along. 
See  Fig.  2  for  both  ways.  The  heavy 
tube  is  to  be  preferred,  in  that  the 
parallel  operation  of  tubes  is  not  uni- 
versally attended  with  success.  A  way 
out  of  this  difficulty  is  outlined   below. 

A  suitable  power  tube  for  such  work 
is  the  new  202A  tube,  ordinarily  em- 
ployed for  transmission  or  speech  am- 
plification, or  the  Western  Electric 
216A  tube  as  used  for  power  amplifica- 
tion. The  latter  may  be  easily  adapted 
to  the  common  amplifier  circuit  since 
it  calls  for  no  other  changes  than  the 
use  of  a  1  ampere  filament  rheostat  and 
a  boost  in  the  plate  voltage  to  about 
150.  It  is  easy  to  get  this  extra  plate 
voltage,  inasmuch  as  it  is  needed  for  the 
resistance-coupled  amplifier  anyway. 

With  a  heavier  tube  in  the  last  stage 
and  with  paralleled  "A"  tubes  of  the 
ordinary  type,  the  grid  leak  resistance 
must  be  reduced  somewhat.  The  re- 
quired leak  may  be  J^  megohm  to  .1 
megohm — a  lower  resistance  than  .1 
never  being  necessary.  If  a  millimeter 
is  at  hand,  the  grid  biases  and  plate 
voltages  can  be  adjusted  to  a  nicety, 
so  that  the  plate  current  is  not  too  high 
for  the  tube  in  use  nor  so  low  that  it 
fails  to  amplify  weak  impulses  as  well 
as  strong  ones.  In  general,  the  grid 
bias  should  be  made  more  and  more 
negative  until  both  quality  and  volume 
decrease    noticeably.       The    adjustment 


of  grid  bias  has  slight  effect  in  the  case 
of  resistance-coupled  tubes  insofar  as 
quality  is  concerned,  so  long  as  there  is 
sufficient  leakage  from  the  grid  to  pre- 
vent the  tube  from  blocking  with  piled- 
up  negative  electric  charges.  The  use 
of  3  to  4  }4  volts  negative  is  helpful  in 
that  it  reduces  the  plate  current  some- 
what, thereby  saving  the  "B"  battery. 
Grid  bias  adjustment  for  the  last  am- 
plifier tube  or  tubes  is  very  critical, 
however,  and  an  injudicious  biasing 
may  result  in  a  plate  current  twice 
normal  without  much  change  in  quality. 
The  "B"  battery  won't  last  very  long 
under  such  treatment. 

About  the  Speakers 

THE  use  of  headphones  at  various 
points  in  the  resistance  amplifier 
will  show  that  amplification  of  all  stages 
is  going  on  undistortedly.  And  with 
the  last  stage  properly  adjusted  and 
supplied  with  a  heavy  tube  or  paralleled 
tubes,  the  output  is  practically  undis- 
torted  and  contains  voice  and  music 
frequencies  of  an  extremely  wide  range, 
just  as  put  into  the  transmitting  micro- 
phone. To  take  full  advantage  of  this  clear 
output,  the  reproducer  should  be  capable 
of  reacting  to  ALL  of  these  frequencies. 
Frankly,  however,  this  cannot  be 
done.  There  is  NO  ONE  loud  speaker, 
so  far  developed,  which  does  not  favor 
certain  frequencies,  when  pushed  to 
strong  volume.  Usually,  certain  fre- 
quencies are  favored  even  on  weak 
volume.  This  is  due  in  the  main  to  the 
size  of  the  diaphragm,  whether  it  be  of 
metal  such  as  a  disc,  or  a  cone  of  parch- 
ment or  paper.  A  small  diaphragm 
favors  the  high-pitched  notes  of  the 
soprano,  women's  voices,  the  flute, 
violin  and  the  like.  On  the  other  hand, 
the  cone  speaker,  with  its  large  expanse 
of  vibrating  material,  delivers  the  low 
frequencies  with  greater  vigor,  like  the 
bass  singer,  the  violin,  the  chords  on  the 
harp  and  chords  on  the  piano  and  so  on. 
A  loud  speaker  has  yet  to  be  developed 
which  does  not  depend  upon  some  vi- 
brating system  by  which  the  sound 
waves  are  set  in  motion.  And  any  such 
vibrating  system,  depending  upon  its 
magnitude,  has  more  or  less  of  a  "natural 


period"  of  vibration,  at  and  near  which 
it  may  be  most  easily  set  into  vibration. 
Hence,  although  the  current  through  the 
windings  of  the  unit  may  pulse  with 
frequencies  of  a  very  wide  range,  the 
diaphragm  or  reproducing  system  is 
more  readily  set  into  motion  by  fre- 
quencies near  its  natural. 

Assuming,  therefore,  that  we  cannot 
hear  both  high  and  low  notes  with  any 
single  loud  speaker — what  is  the  natural 
recourse  in  order  that  we  SHALL  hear 
both  these  frequency  ranges?  Why — 
to  use  TWO  loud  speakers!  This  may 
seem  like  a  radical  suggestion  and  yet 
anyone  willing  to  try  such  a  combination 
will  be  at  once  convinced  of  its  great 
value.  Take  an  ordinary  horn  type 
of  loud  speaker,  with  a  diaphragm  vary- 
ing from  two  to  five  inches  in  diameter 
and  connect  in  parallel  with  it  a  cone 
type  of  speaker  or  some  other  type  of 
speaker  having  a  very  large  vibrating 
system.  Arrange  switches  so  that  either 
may  be  heard  separately,  or  both  to- 
gether. It  might  appear  advisable  to 
employ  one  speaker  for  high  notes  and 
the  other  for  low  notes,  but  such  does 
not  prove  to  be  the  case.  Every  fre- 
quency is  accompanied  by  "overtones," 
which  are  other  vibrations  that  are 
multiples  of  that  frequency.  Thus,  if 
it  were  no'  for  the  overtones,  we  should 
have  a  ha-  J  time  of  it  to  distinguish 
one  woman's  voice  from  another's  or 
to  detect  the  difference  in  tone  quality 
between  a  flute  and  a  fife,  or  between  a 
trombone  and  a  cello. 

Adding  the  Overtones 

By  the  addition  of  these  overtones 
the  differentiating  qualities  stand  out 
plainly.  Using  two  loud  speakers  in 
this  manner,  the  faint  overtones  giving 
richness  to  the  tenor's  voice  improve  the 
color  and  depth  of  reproduction  in  an 
almost  indescribable  fashion,  yet  are 
evident  to  even  an  inexperienced  ear. 
It  is  very  easy  to  point  out  the  improve- 
ment when  the  two  speakers  are  con- 
nected with  switches  for  quick  changes 
with  either  or  both  in  circuit.  Using  the 
horn  speaker,  with  a  jazz  band  coming 
in,  the  melody  stands  out  most  promi- 
(Tnm  to  page  67) 


Fig.    3 —  Using  two  loud  speakers  to  cover  the  entire  musical  range,  one  for  higher  frequencies  and  the  other  for  low;  the  double  tube 
connection  allows  a  separate  tube  for  each  speaker.     Fig.    5 — Details  of  the  mandolin  low-note  loud  speaker. 


14 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


Where  Does  the 
POWER 

for  Your 

RADIO 

Come  From? 

Erroneous  Impression  that 
All  the  Energy  Comes  from  the  Transmitter; 
Power  Creating  Sounds  in  Home  Due  to 'Bf  Voltage 


WHEN  your  loud  speaker  is  re- 
producing a  good  program  ol 
dance  music  with  sufficient  vol- 
ume for  half  a  dozen  couples,  an  appre- 
ciable amount  of  energy  is  required  to 
produce  such  loud  signals.  Where  does 
that  energy  come  from?  How  much  of 
it  does  the  transmitter  of  the  distant 
station  contribute? 

Actually,  a  receiving  set  with  90  volts 
of  "B"  battery  may  pass  as  much  as  6 
milli-amperes  through  the  plate  circuit 
of  the  last  tube.  This  amounts  to  approx- 
imately half  a  watt.  Yet,  the  power 
received  from  the  broadcasting  station 
is  frequently  less  than  one-millionth 
of  a  watt!  The  power  actually  creating 
sound  in  your  home,  comes  from  the 
faithful,    hard-working    "B"    battery. 

Radio  transmission  and  reception  re- 
quire many  processes  and  conversions, 
all  of  which  can  be  successively  performed 
without  the  introduction  of  any  ex- 
traneous noises  or  distortion. 

But,  unless  you  understand  the  many 
steps  which  occur  from  the  time  the 
program  is  rendered  in  the  studio  until 
it  is  finally  re-created  in  your  home,  you 
cannot  fully  appreciate  how  anything 
approaching  that  fidelity  of  reproduction 
is  attainable.  Numerous  explanations 
of  the  transmitting  and  reception  process 
have  been  written,  using  freely  such  terms 
as  "sound  waves,"  "radio  frequency," 
"electro-magnetic  waves"  and  "audio- 
frequency." Usually  these  terms  con- 
vey only  a  vague  meaning  to  the  non- 
technical reader.  But  it  is  not  difficult 
to  visualize  just  what  takes  place  from 
the  time  the  program  is  rendered  at  the 
studio  until  it  is  finally  reproduced  in 
your  home. 

We  begin  first  with  sound  waves,  the 
result  of  the  artist's  performance  in  the 
studio.  A  musical  program  is  a  complex 
combination  of  different  sound  waves 
having  various  frequencies,  between 
sixteen   and   five  thousand   impulses  per 


By  EDQAR  H.  FELIX 


second.  Each  individual  note  emitted 
by  musical  instruments  consists  of  a 
fundamental  frequency,  determining  the 
pitch  of  the  sound,  and  a  number  of 
harmonics,  serving  to  give  each  instru- 
ment its  individual  character.  You  can 
distinguish  whether  it  is  the  middle  C 
or  any  other  pitch  by  the  frequency  of 
the  fundamental. 

The  harmonics,  consisting  of  multiples 
of  the  fundamental  pitch  set  up  by  each 
instrument,  enable  you  to  distinguish 
between  the  piano,  violin,  saxaphone  or 
any  other  instrument.  For  instance,  if 
the  C  an  octave  below  the  middle  C 
is  played  on  the  piano,  129  pulsations 
per  second  are  set  up.  This  is  the  fun- 
damental frequency,  determining  the 
pitch  as  that  of  the  C  below  middle  C. 
Also,  there  are  harmonics  of  259,  388, 
517,  647,  796  and  so  on,  consisting  of 
multiples  of  the  fundamental.  The 
violin,  sounding  the  same  pitch,  has  the 
same  fundamental  and  the  same  har- 
monics. It  is  the  distribution  of  the 
energy  on  these  harmonics  which  enables 
you  to  distinguish  whether  there  is  a 
violin,  piano,  flute,  oboe  or  clarinet 
being  played. 

Tuning  Fork  Purest 

\  STUDY  of  the  nature  of  musical 
-' ■**-  sounds  is  indeed  an  interesting  one. 
The  tuning  fork  gives  the  purest  tone 
because  all  of  its  energy  is  radiated  in 
the  fundamental.  The  flute  comes  next 
in  purity  of  tone.  When  a  low  tone  is 
played  softly  on  this  instrument,  95% 
of  the  energy  is  concentrated  in  the 
fundamental,  with  just  a  trace  of  energy 
in  the  harmonics:  When  lower  registers 
are  played  powerfully,  or  overblown, 
the  fundamental  is  weak;  being  just 
loud   enough    lo   characterize   the   pitch; 


the  first  overtone  becomes  the  most 
prominent;  the  second  is  of  the  same 
order  of  energy  as  the  first;  the  third  is 
larger  than  the  second.  On  the  other 
hand,  the  middle  registers  of  the  flute 
played  powerfully  are  again  almost  pure 
tones. 

The  oboe  has  twelve  or  more  harmonics, 
the  fourth  and  fifth  predominating,  with 
30  and  36%  respectively  of  the  total 
loudness. 

Each  instrument,  therefore,  has  its 
peculiar  characteristics,  varying  through 
the  various  registers.  All  of  these  are 
combined  and  utilized  by  the  composer 
to  secure  pleasing  and  harmonious 
effects. 

When  you  consider  the  fact  that 
sometimes  as  many  as  eighty  instru- 
ments are  contributing  to  an  orchestral 
program  involving  at  any  particular 
instant  half  a  dozen  different  funda- 
mentals and  five  times  that  number  of 
harmonics,  the  composition  of  all  these 
air  wave  impulses  is  indeed  highly 
complex.  This  is  the  first  step  in  radio 
telephone  transmission — the  creation  of 
sound  waves  consisting  of  air  wave 
impulses  of  many  different  fundamental 
frequencies  and  a  wealth  of  harmonics. 

The  first  conversion  process  is  the  use 
of  these  complex  air  waves  in  controlling 
an  electric  current.  The  microphone 
effects  this  step.  It  consists  of  a  dia- 
phragm which  vibrates  when  sound  waves 
strike  it,  just  as  your  own  ear  drums  do. 
Instead  of  affecting  nerves  which  registei 
in  the  brain,  the  microphone's  ear  drum 
compresses  carbon  granules  packed  loose- 
ly behind  it.  When  highly  compressed 
by  a  powerful  sound  wave,  the  resistance 
of  the  carbon  granules  falls  markedly. 
Less  powerful  sound  waves  do  not  reduce 
the  resistance  as  much.  The  microphone 
is  placed  in  series  with  a  steady  source  ol 
potential  as  the  resistance  of  the  micro- 
(  Turn  to  page  50) 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


15 


A  back  view  o] 
the  amplifier  de- 
scribed by  Mr. 
Pfaff,  showing 
sockets  and  oth- 
er instruments 
neatly  arranged. 


For  DISTORTIONLESS  Reception 

A  NEW  AUDIO  FREQUENCY  AMPLIFIER— RESISTANCE  COUPLED 


AVERY  good  parallel  may  be 
drawn  between  the  progress  of 
radio  broadcasting  receivers  with 
the  public,  and  the  development  of  the 
phonograph,  with  respect  to  the  stand- 
ard of  quality  of  reproduced  signals 
that  was  demanded  several  years  ago, 
and  the  standard  that  today  will  satisfy 
the  discriminating  enthusiast.  When 
radio  first  came  into  popularity,  the 
influence  of  the  telegraphing  amateur 
was  most  strongly  in  evidence  in  audio 
amplifiers,  for  this  amateur  desired  not 
quality  of  reproduction,  but  high  ampli- 
fication per  stage.  In  fact,  the  ideal 
audio  amplifier  for  telegraph  reception 
would  be  one  that  would  accentuate  to 
the  greatest  possible  extent  only  the 
particular  frequencies  used  for  modulat- 
ing the  transmitting  wave. 

Because  of  these  requirements,  prac- 
tically nothing  but  transformer  coupled 
audio  amplifiers  were  in  use,  the  trans- 
formers themselves  generally  having  a 
step-up  ratio  of  six  to  one  or  ten  to  one. 
Their  design  was  such  that  they  amplified 
best  at  some  hump  in  their  curve;  in 
the  case  of  one,  built  by  a  nationally 
known  manufacturer,  the  maximum 
amplification  secured  at  twelve  hundred 
cycles  was  several  times  that  obtained 
at  100  cycles.  Then,  as  broadcasting 
came  in,  requirements  changed,  and  the 
desirable  amplifier  for  this  class  of 
reception  was  one  that  would  amplify 
uniformly  all  frequencies  from  sixty 
to  six  thousand  cycles. 

Transformer  design  was  improved, 
with  a  general  tendency  among  manu- 
facturers   and    designers    to    reduce    the 


By  Ernest  R.  Pfaff 

step-up  ratios  used.  This  resulted  in 
the  present  day  transformers  which 
amplify  with  very  good  uniformity  all 
frequencies  between  two  hundred  and 
six  thousand  cycles.  But  even  in  the 
best  of  audio  transformers,  there  is  a 
very  decided  drop  in  amplification  below 
two  hundred  cycles,  which  becomes 
greater  as  the  frequency  decreases. 
At  sixty  cycles,  the  amplification  of  the 
average  audio  transformer  is  practically 
negligible,  as  compared  to  its  amplifica- 
tion at  frequencies  above  two  or  three 
hundred   cycles. 

The    Organ's    Faults 

A  NYONE  who  has  listened  to  an 
-^*-  organ  as  received  on  the  average 
radio  set  is  only  too  well  aware  of  the 
absence  of  the  lower  frequency  notes. 
When  listening  to  the  organ,  say  in  a 
church,  we  are  all  familiar  with  the  deep 
vibrations  evident  on  the  low  notes; 
yet  how  many  radio  enthusiasts  have 
ever  felt  the  walls  of  their  homes  vibrate 
when  listening  to  a  broadcast  organ 
selection?  But  where  a  resistance  coupled 
audio  amplifier  is  used,  the  fidelity  of 
reproduction  is  so  great  as  to  cause 
doubt  in  the  mind  of  even  the  best 
trained  musician  as  to  whether  the 
selection  heard  is  actually  being  played 
in  his  presence,  or  is  being  broadcast. 
Due  to  the  inherent  characteristics 
of  resistances  when  used  for  coupling 
purposes  in  an  audio  amplifier,  sub- 
stantially  no   discrimination   takes  place 


in  favor  of  one  range  of  frequencies  at 
the  expense  of  another  range,  as  in  a 
transformer  coupled  amplifier.  Trans- 
formers cannot  be  built  to  give  abso- 
lutely uniform  amplification,  due  to 
the  resonance  characteristics  of  the 
windings   that    must    be   used. 

In  actual  practice  two  stages  of 
transformer  audio  amplification  are  about 
all  that  can  be  used,  due  to  the  build- 
ing up  of  noise  in  the  system  and  the 
fact  that  such  an  amplifier  in  conjunction 
with  a  good  receiver  will  give  plenty  of 
volume  for  loud-speaker  operation.  How- 
ever, three  stages  of  resistance  coupled 
amplification  will  be  required  to  give 
the  same  or  slightly  greater  volume, 
since  the  gain  per  stage  in  such  an 
amplifier  is  lower  than  in  a  transformer 
coupled  amplifier.  This  will  be  appre- 
ciated when  it  is  realized  that  one  trans- 
former and  one  tube  will  give  a  voltage 
gain  of  about  18.  When  the  second 
stage  is  added,  using  exactly  the  same 
equipment,  this  figure  falls  off,  due  to 
certain  inherent  characteristics  of  such 
systems.  Therefore,  we  can  allow  a 
gain  of  18  in  the  first  stage  and  about 
13  in  the  second  stage,  or  an  over-all 
gain  for  the  system  of  18x13,  or  234. 
This  means  a  signal  is  234  times  stronger 
when  it  comes  out  of  such  an  amplifier 
than  it  was  when  it  went  in.  These 
figures  are  low,  for  great  amplification 
cannot  be  obtained  from  a  transformer 
amplifier     designed     for     good     quality. 

In  the  case  of  a  three-stage  resistance 
amplifier  the  gain  per  stage  will  be  about 
the  same  for  each  stage,  since  the  drop 
encountered    in    the    previous   case    does 


16 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


Figure  3. 


A  bottom  view  of  the  amplifier,  giving  a  good  idea  of  how  resistances 
and  condensers  are  mounted. 


not  apply  to  any  appreciable  extent. 
Therefore,  we  can  allow  a  gain  of  about 
6.5  per  stage  or  about  81  %  of  the  ampli- 
fication factor  of  an  average  tube. 
This  in  three  stages  gives  a  total  ampli- 
fication of  275,  or  slightly  more  than 
that  obtained  with  two  transformer 
stages. 

Expense 

FROM  the  standpoint  of  expense, 
the  resistance  system  can  be  built 
as  cheaply,  or  more  cheaply,  than  the 
transformer  system,  due  to  the  lower 
cost  of  the  component  parts.  An  addi- 
tional tube  will  be  required,  which  will 
about  even  up  the  price  of  the  two 
outfits. 

While  135  volts  will  be  required  for 
the  resistance  system,  the  B  battery 
current  consumption  will  be  only  about 
nine  millamperes,  as  against  ten  to 
eleven  for  the  transformer  system. 
Therefore,  the  B  battery  expense  for 
both  systems  being  about  equal,  with 
the  initial  battery  expense  higher  for  the 
resistance  amplifier,  and  the  upkeep 
cost  of  the  transformer  amplifier  nearly 
balancing  this,  there  is  no  reason  why 
the  average  fan  should  not  enjoy  the 
wonderful  quality  to  be  obtained  with 
the  resistance 
system. 

The  amplifier 
unit  described 
herewith  is  the 
result  of  consider- 
able experiment, 
and  if  it  may  be 
judged  on  its  per- 
formance, its  con- 
struction will  be 
very  decidedly 
warranted  by  the 
true  music  lover. 
It  is  so  designed 
that  the  unit  itself 
may  be  mounted 
upon  a  standard 
panel,  or  it  may 
be  incorporated 
just  as  it  is  in 
any  standard  re- 
ceiver circuit  in 
place  of  the  con- 
ventional trans- 
former amplifier. 
Due    to    its    com- 


pact arrangement,  it  may  be  placed 
in  less  than  the  space  required  for  the 
standard  amplifier  in  almost  any  receiver 
design. 

The  constants  of  this  amplifier  are 
so  proportioned  that  the  maximum 
amplification  will  result  with  a  minimum 
of  current  consumption.  The  .0075 
coupling  condensers  have  a  compara- 
tively low  reactance  to  the  frequencies 
to  be  handled,  and  are  a  far  more  prac- 
tical size  to  work  with  than  those  of 
a  larger  capacity.  Theoretically,  these 
condensers  should  be  on  the  order  of  one 
to  five  microfarads,  but  practically, 
.0075  is  entirely  large  enough.  The 
use  of  one  of  these  condensers  connected 
from  plate  to  filament  of  the  last  stage — 
a  point  commonly  overlooked — prevents 
poor  quality  often  experienced  with 
resistance   amplifiers. 

The  coupling  resistances  are  of  1-10 
megohms     or      100.000     ohms.        When 


Figure  2.     Wiring  diagram  for  distortionless  audio  amplifier.     As  all  parts  have    been 

illustrated  pictorially,  rather  than  in  symbols,  this  diagram  is  very  easy  to  follow,  even  by 

the  inexperienced  set  builder. 


using  135  volts  on  the  amplifier,  the 
tube  resistance  may  be  considered  as 
about  20,000  ohms,  which  give  a  total 
plate  circuit  resistance  of  120,000  ohms, 
across  which  is  apjlied  135  volts.  For 
practical  purposes,  it  may  be  considered 
that  this  voltage  divides  so  that  the 
actual  plate  voltage  of  the  first  two 
tubes  is  about  34,  so  that  no  "C"  battery 
will  be  required.  If  a  higher  resistance 
were  used,  a  higher  plate  voltage  would 
be  necessary,  but  if  a  lower  resistance 
were  used,  the  amplification  would  fall 
off  badly.  Further,  the  size  of  these 
coupling  resistances  is  about  five  times 
the  tube  resistance,  which  insures  prac- 
tically uniform  amplification  at  all  fre- 
quencies to  be  handled.  Actually, 
the  variation  in  amplification  between 
60  and  6,000  cycles  is  only  a  few  per  cent. 
The  grid  leaks  are  of  such  a  size  that 
they  will  prevent  blocking  of  the  system, 
and  maintain  the  grid  potential  of  the 
various  tubes  at  a  satisfactory  operating 
value.  One-half  megohm,  or  500,000 
ohms,  is  used  on  the  first  stage,  with 
one-quarter  megohm,  or  250,000  ohms, 
on   the  second   and  third  stages. 

Because  of  the  high  resistance  used 
for  coupling  the  output  of  the  receiver 
(or  detector)  to  the  amplifier,  the  plate 
voltage  of  the  detector  should  be  about 
90  volts,  instead  of  the  customary  45. 
If  the  amplifier  connects  to  a  receiver 
using  audio  amplification,  the  plate 
voltage  of  the  last  tube  in  the  receiver 
should  be  run  up  to  90  or  135  volts. 
The  resistance  in  the  plate  circuit 
of  the  last  tube  is  only  that  of  the  loud 
speaker — generally  2,000  ohms — so  that 
practically  all  of  the  plate  voltage  used 
is  applied  to  this  last  tube.  This  being 
the  case,  a  C  battery  should  theoretically 
be  used  in  series  with  the  last  tube's 
grid  leak,  of  about  3  to  6  volts.  Actually 
this  does  not  improve  reproduction, 
and  so  it  is  not  shown  in  the  amplifier 
circuit.  It  will  reduce  the  B  battery 
consumption  somewhat,  and  may  be 
incorporated  if   desired. 

The  current  consumption  of  the  first 
two  tubes  is  on  the  order  of  1.13  milli- 
amperes  per  tube,  while  for  the  last 
tube  it  is  about 
12  to  14  mils. 
This  makes  a  total 
of  14J4  to  16^ 
mils,  for  the  three 
stages,  which  may 
be  cut  by  four 
or  five  mils,  by 
using  the  C  bat- 
tery referred  to, 
ON  THE  LAST 
STAGE   ONLY. 

Figure  3  is  a 
bottom  view  of 
the  unit,  showing 
placement  of  the 
six  resistances  and 
four  condensers, 
these  being  at- 
tached to  a  bake- 
lite  strip  carrying 
the  five  binding 
posts,  which  is  in 
turn  fastened  to 
three  panel- 
mounting  sockets. 
(Turn  to  page  60) 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour  17 


An  IMPROVED  Slide 
Wire  Bridge 


THE  slide  wire  bridge  described  in 
the  February  issue  of  RADIO  AGE 
has  proven  itself  so  popular  and  of 
such  an  asset  to  set  builders  and  experi- 
menters that,  in  answer  to  numerous 
requests,  the  writer  has  completed  an 
improved  model  of  this  instrument, 
wherein  the  construction  has  been  so 
simplified  as  to  bring  it  within  reach  of 
the  most  inexperienced  novice  and  yet 
retain  the  accuracy  and  ease  of  operation 
so  necessary  in  an  instrument  of  this 
kind. 

This  instrument  seems  to  have  filled 
a  long  felt  want  for  the  layman,  making 
it  possible  for  him  to  measure  the  capacity 
of  condensers,  the  impedance  of  coils, 
transformers    and    such,    and    to    enable 


By  H.  FRANK  HOPKINS 

A  New  Design  for 
Measuring  Capacity 


him  to  match  and  balance  his  parts  with 
a  close  degree  of  accuracy,  heretofore 
attainable  by  only  the  more  advanced 
fan  with  his  home  laboratory  and  his 
knowledge  of  radio  and  electrical  phe- 
nomena. 

Time    after   time,    the    importance    of 
matched     parts    and    a     well     balanced 


receiving  set  has  been  explained,  yet 
very  few  set  builders  know  how  to  balance 
and  match  the  parts  they  are  about  to 
build  or  use.  With  the  aid  of  this  in- 
strument it  is  within  easy  reach  of  the 
most  inexperienced  novice  who  has  only 
a  limited  knowledge  of  the  radio  or 
electrical  science  as  well  as  to  the  more 
experienced  fan  with  his  advanced  ex- 
perience and  array  of  equipment.  All 
that  is  necessary  for  the  successful  opera- 
tion of  the  slide  wire  bridge  is  a  knowl- 
edge of  simple  arithmetic  and  the  use 
of  a  little  good  judgment. 

WHILE  it  is  true  that  there  are  other 
instruments  that  will  show  a  little 
more    accuracy    on    certain    operations, 


JV/ZP/MG     D I  AG  A" AM      OF       COMPLETE 
/NST/?t/A7EN  T.    fSEE  HIAIHG    TABIC) 

Circuit    diagrams    eoa   the 
/M  PROVED      S£/D£~     W/f?£     BF/DG£- 


SCHEMATIC     DIAGRAM     OF 
THE     BA/fiGE     CIRCUI  T. 


tfH  &/ 


18 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


such  as  peaking  transformers  with  a 
wave  meter,  measuring  capacity  by  use 
of  a  modified  form  of  Wheatstone  Bridge, 
called  a  Capacity  Bridge,  and  such,  it 
also  becomes  more  difficult  because  more 
intricate  mathematical  formulae  and 
additional  expensive  equipment  are  re- 
quired. The  slide  wire  bridge  covers 
more  ground  than  any  of  the  other  in- 
struments and  it  also  keeps  the  mathe- 
matics down  to  plain  multiplication, 
division  and  subtraction,  while  it  shows 
results  as  accurate  as  necessary  for  this 
type  of  work.  It  is  also  the  only  simple, 
accurate  method  of  determining  im- 
pedance at  various  frequencies. 

All  of  the  parts  used  in  building  this 
instrument  have  been  given  a  desig- 
nating letter  or  number;  each  terminal 
is  numbered  both  in  the  circuit  diagrams 
and  the  wiring  table.  This  same  desig- 
nation is  applied  throughout  the  article 
and  in  the  formulae  that  follow  so  as  to 
readily  recognize  each  part  and  its  place 
in  the  circuit.  The  parts  used  in  building 
the  instrument  are  all  standard  equip- 
ment and  may  be  purchased  from  any 
reliable  dealer.  The  parts  should  not 
cost  the  fan  over  ten  dollars.  They  are 
as  follows: 

One — 400  Ohm  Potentiometer  (P) 

One — High  Frequency  Buzzer.  (900 
to  1000  cycles)  (C) 

One — Small  induction  coil  or  open 
core  transformer.  Construction  of 
the  proper  type  described  in  this 
article  (I) 

One — 3  to  4  1-2  volt,  Flash  light 
battery  (E) 

One— Metal  plate  dial  (S) 

One — Dial  Marker  (SM) 

One — Battery  switch  (SW) 

Six— Binding  posts  (X,  XI,  Y,  Yl, 
R,  Rl) 

One — Set  of  brass  clips  for  mount- 
ing flash  light  battery  (E) 

One — 5"x7"xl-8"  Composition  pan- 
el 

One — 5"x7"x5"   Case    or   wood    box 

X — Miscellaneous  screws,  wire,  sol- 
der, etc. 

The  first  step  in  building  the  instru- 
ment will  be  to  lay  out  and  drill  the  panel 
for  mounting  the  potentiometer  (P). 
A  hole  one  half  inch  in  diameter  should 


be  drilled  in  the  panel,  3  1-2"  down  from 
the  top  and  2  1-2  "  in  from  the  side.  This 
is  for  the  dial  shaft  of  the  potentiometer 
and  is  large  so  as  to  prevent  the  shaft 
from  binding  against  the  panel.  The 
mounting  holes  for  the  potentiometer 
will  then  be  marked  and  drilled.  These 
holes  will  be  countersunk  from  the  top 
of  the  panel  to  take  a  number  six,  flat- 
head  machine  screw. 

Four  holes  will  be  drilled  and  counter- 
sunk to  take  number  six,  oval  head  wood 
screws.  These  are  for  mounting  the 
panel  to  the  case  or  box  for  the  instru- 
ment, and  care  should  be  taken  to  see 
that  they  are  not  too  close  to  the  outer 
edge  or  the  screw  may  split  the  box. 

When  the  panel  is  completely  drilled, 
the  potentiometer  (P)  will  be  mounted 
and  the  dial  attached.  The  hole  for 
mounting  the  dial  marker  will  then  be 
located  and  drilled  to  fit.  The  scale 
for  the  dial  will  complete  the  top  panel 
layout.  However,  we  will  lay  this  part 
of  the  bridge  aside  for  the  present  and 
start  on  the  box  equipment. 

Mounting  the  Equipment 

rPVVO  brass  details,  shown  in  figure 
J-  three,  will  be  made  and  fastened  to 
the  bottom  of  the  box  as  shown  in  figure 
four.  These  details  will  be  spaced  to 
fit  the  type  of  flash  light  battery  to  be 
used.  Number  six  round  head  wood 
screws  will  be  used  to  mount  all  of  the 
equipment  except  the  buzzer;  this  will 
have  the  screws  usually  furnished. 

An  induction  coil  (I)  or  open  core 
transformer,  having  a  low  impedance 
value  and  a  ratio  of  transformation  of 
about  three  to  one,  may  be  purchased 
for  about  one  dollar,  or  it  may  be  made 
at  an  even  smaller  expense,  as  follows: 
A  bundle  of  soft  iron  wire,  No.  20  B 
and  S  gauge,  having  a  total  diameter  of 
about  five-eighths  of  an  inch  and  an 
overall  length  of  four  inches  will  be 
securely  tied  and  wrapped  with  about 
ten  turns  of  good  wax  paper.  Two  pieces 
of  wood,  one  quarter  of  an  inch  thick 
and  one  and  one  half  inches  square,  will 
have  a  hole  drilled  in  the  center  large 
enough  to  fit  snugly  over  one  end  of  the 
iron  core.  One  of  these  pieces  will  be 
made    fast    to    each    end    of   the   bundle 


of     soft    iron     wire,     making     a     spool. 

Shellac  or  glue  may  be  used  to  fasten 
all  parts,  and  it  would  be  well  to  tie  all 
of  the  windings  with  shellac  or  glue  when 
each  coil  is  completed. 

The  primary  coil  will  be  wound  in 
even  layers  directly  over  the  iron  core 
on  the  wax  paper  wrappings.  Two  hun- 
dred turns  of  No.  20  B  and  S  gauge, 
double  cotton  covered,  copper  magnet 
wire  will  be  required.  Both  ends  of  this 
winding  will  be  brought  out  through 
holes  in  one  of  the  end  pieces  of  the  spool 
and  the  entire  coil  covered  with  about 
six  turns  of  wax  paper,  thus  completing 
the  primary  coil. 

The  secondary  coil  will  be  wound  di- 
rectly over  the  primary  coil  and  on  top 
of  the  wax  paper  wrappings.  Be  careful 
to  wind  the  wire  for  this  coil  in  the  same 
direction  as  was  done  for  the  primary 
coil.  Six  hundred  turns  of  No.  30  B 
and  S  gauge,  double  cotton  covered, 
copper  magnet  wire  will  be  necessary, 
bringing  each  end  of  the  winding  out 
through  holes  in  the  end  piece  opposite 
to  the  primary  leads. 

It  would  be  well  to  splice  a  piece  of 
stranded  wire  to  th"e  secondary  coil 
ends,  taking  two  or  three  turns  and 
bringing  out  through  the  end  piece  in 
place  of  the  No.  30  solid  wire,  as  this 
is  rather  delicate  and  hard  to  handle. 
Ten  turns  of  wax  paper  will  then  be 
wound  around  the  coil  and  made  fast, 
completing  the  induction  coil,  (I).  This 
coil  will  then  have  four  leads  or  terminals. 
The  inside  lead  of  the  primary  coil  will 
be  (II),  the  outside  primary  lead  (12), 
the  inside  secondary  lead  will  be  (13) 
and  the  outside  secondary  lead  will  be 
(14).  The  coil  will  then  be  mounted  in 
the  box  or  case  as  shown  in  figure  four. 

The  Buzzer 

A  HIGH  frequency  buzzer,  (900  to 
1000  cycles)  may  be  secured  from 
any  reliable  dealer  for  about  two  dollars. 
It  should  be  enclosed  under  a  metal 
cover.  A  buzzer  of  this  type  is  required 
to  set  up  a  current  whose  frequency  is 
somewhere  near  the  average  frequency 
of  voice  currents  to  better  balance  and 
measure  equipment  subject  to  voice 
(Turn  to  page  53) 


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RADIO  AGE  for  October,  1025 


The  Magazine  of  the  Hour  19 


Electricity — The  Life  of  the  World 


The  Wise 

Old  Man 

of  the 

Night 

Sheds  Some 

Light  on 

Radio's 

Miracles 


"You  were  wonder- 
ing what  keeps  the 
sun,  moon  and  stars 
in  their  relative 
positions,  and  what 
effect  they  have  on 
this  world  of  ours," 
said  the  Old  Man. 
"Well,  I  will  tell 
you." 


A  STORY  THAT  DELVES  INTO  RADIO'S  FUTURE— BY  FRANK  D.  PEARNE 


BILLIE  McINTYRE  leaned  back 
from  the  key  and  stretched  out 
his  arms  with  a  deep  yawn.  This 
had  been  a  particularly  interesting  night 
for  Billie,  as  he  had  reached  more  of  his 
ham  friends  in  the  last  three  hours  than 
ever  before  in  a  single  night.  Being 
somewhat  of  a  dreamer,  his  mind  began 
to  wander  from  the  dots  and  dashes  of 
the  last  few  hours  to  the  more  mysterious 
things  of  life.  He  marvelled  at  the  won- 
ders of  nature,  for  his  West  Virginia 
friend  had  just  clicked  off  the  informa- 
tion that  a  terrific  thunderstorm  was 
about  to  break  and  gazing  out  through 
the  window  he  looked  upon  as  clear  and 
beautiful  a  sky  as  he  had  ever  seen. 

It  was  hard  to  imagine  a  thunder 
storm   from   a   sky   like   that.  What 

difference  a  few  hundred  miles  could 
make;  what  was  this  great  power  that 
could  turn  these  heavens  into  a  hunt- 
dering  whirlpool  of  wind,  rain  and 
lightning? 

Much  of  his  life  had  been  spent  in 
dreaming,  studying  and  experimenting. 
He  watched  the  magazines  and  read  the 
best  books,  and  the  many  theories  of 
radio  transmission  and  reception  which 
he  absorbed  in  the  process  had  made 
him  wonder  what  it  was  all  about. 
To  Billie,  there  were  many  things  yet 
to  be  explained  to  his  satisfaction.  Light- 
ing up  the  old  pipe,  he  walked  across 
the  room  to  the  window  and  sat  down 
gazing  out  at  the  sky  above  him. 

What  were  all  these  tiny  stars  blinking 
at  him?  Why  were  they  always  there 
in  the  same  place  and  order  night  after 


night,  and  what  influence  did  they 
exert  upon  this  little  world  of  ours? 

A  Stranger  Enters 

r  I  ''HESE  and  many  other  questions 
-*-  flitted  across  his  mind  as  he  became 
deeply  absorbed  in  the  wonderful  spec- 
tacle before  him. 

Suddenly  he  became  conscious  of  the 
fact  that  he  was  not  alone,  and  even 
before  he  could  turn  around  he  heard 
a  deep  voice  behind  him  drawling  out 
the  question: 

"Well,  young  man,  have  you  figured 
it  all  out?" 

Turning  quickly,  he  beheld  a  little 
gray  haired  old  man  looking  at  him 
from  across  the  room.  Strange  to  say, 
Billie  was  not  startled.  It  all  seemed 
perfectly  natural  for  some  reason  or 
other,  and  something  seemed  to  assure 
him  that  even  at  such  a  late  hour  what- 
ever might  be  the  mission  of  this  queer 
looking  individual,  it  meant  no  harm 
to  him.  How  he  had  found  his  way  into 
the  little  laboratory  through  a  carefully 
locked  door  did  not  seem  to  bother  him. 
Rising  slowly  from  his  chair,  Billie 
walked  toward  his  visitor. 

"I — I  don't  seem  to  remember  you, 
sir,  but  there  is  something  very  familiar 
about  your  face,"  he  said. 

The  little  old  man  chuckled,  "No, 
son,  there  is  nothing  strange  about  your 
not  remembering  me,  for  I  passed  on 
from  this  earth  many  years  before  you 
were  born.  I,  too,  struggled  with  these 
problems  of  yours — struggled  hard  and 
patiently — when    I    was   young,    and   for 


the  little  which  I  did  accomplish,  science 
has  rewarded  me  by  mentioning  my 
work  and  experimenting  and  by  placing 
my  image  in  the  hall  of  fame." 

Suddenly  the  light  of  recognition  came 
to  Billie.  That  face  he  had  seen  in  some 
of  his  old  books.  "You  are — ?"  he 
exclaimed,  but  the  little  man  held  up 
his  hand  and  stopped  him. 

"Never  mind  who, — my  purpose  in 
coming  here  is  to  get  you  but  of  this  rut 
— to  give  you  a  new  train  of  thought 
and  to  try  and  make  you  do  a  little 
thinking  for  yourself." 

Billie  made  a  gesture  and  opened  his 
mouth  to  speak,  but  the  little  old  man 
stopped  him. 

"Please  do  not  interrupt  me,  for  I 
have  much  to  say  to  you  in  the  short  time 
I  can  be  with  you,  and  I  know  what  you 
are  going  to  say.  Electricity  is  the  life 
of  the  world.  You  were  wondering 
about  the  sun,  moon  and  stars,  and  what 
keeps  them  in  their  relative  positions, 
and  what  effect  they  have  upon  this 
world  of  ours. 

"Has  it  ever  occurred  to  you  that 
this  planet,  like  the  others,  is  whirling 
around  at  tremendous  speed,  and  that 
this  condition  might  cause  it  to  become 
highly  charged  with  electricity?  Have 
you  ever  tried  to  experiment  with  a 
number  of  very  light  bodies  which  have 
all  been  charged  with  electricity,  and 
noticed  how  they  repel  one  another, 
keeping  them  separated  at  a  distance, 
depending  upon  the  strength  of  the 
charge  which  they  hold,  and  also  that 
when    relieved    of   their   charge    the   re- 


20 


RADIO  AGE  for  October,  1925 


7  he  Magazine  of  /he  Flour 


pulsion  ceases,  or  if  some  of  them  are 
given  a  positive  charge  and  some  a 
negative  charge  they  rush  together? 
What  then  is  more  natural  than  to 
suppose  that  these  planets  with  their 
enormous  electrical  charges — in  fact, 
charges  of  electricity  which  are  so  great 
as  to  be  far  beyond  the  comprehension 
of  man— act  in  the  same  manner  and 
float  around  in  space  at  a  respectful 
distance  from  each  other? 

"Do  you  suppose  that  this  little 
mechanism  which  you  call  a  generator 
really  produces  anything?  You  use  it 
every  night  to  converse  with  your  friends; 
other  so-called  generators  apparently 
supply  the  energy  to  give  light,  heat 
and  power,  but  good,  fair  reasoning 
should  convince  you  that  man  creates 
nothing.  We  are,  in  fact,  prisoners  on 
this  little  planet  and  have  no  power  to 
reach  out  from  it  and  obtain  anything 
which  is  not  already  here.  The  only 
thing  which  you  can  do  is  to  alter  con- 
ditions in  such  a  way  that  these  changes 
may  be  beneficial  to  mankind. 

"Is  it  not  more  reasonable,  then,  to 
suppose  that  your  so-called  generators 
merely  act  in  such  a  way  that  they  make 
use  of  this  great  charge  by  causing  a 
difference  in  its  strength  between  the 
points  covered  by  the  electrical  circuits 
connected  to  them? 

"Fortunately  for  you  and  the  rest  of 
the  human  inhabitants  of  this  earth,  man 
has  not  yet  found  any  means  of  making 
any  appreciable  change  in  this  charge. 
The  small  amount  of  energy  which  he  has 
succeeded  in  moving  from  point  to  point 
has  had  no  effect  upon  the  earth's  loca- 
tion compared  to  other  planets,  but 
should  the  time  come,  when  the  re- 
quirements cause  enough  change  in  this 
charge  to  lessen  its  repelling  effect,  look 
out  for  unusual  things  to  happen.  The 
earth  might  change  its  position  in  re- 
lation to  the  other  planets." 

Billie  listened  intently  as  his  strange 
visitorr  ambled  on.  Many  ideas  suggested 
fanciful  things  as  he  listened.  What 
would  happen  if  the  earth  changed  its 
position?  Life  is  possibly  only  within 
a  small  range  of  temperature.  Any 
slight  change  in  the  position  of  the  earth 
might  cause  it  to  become  so  hot  or  so 
cold  that  the  inhabitants  could  not 
exist.  Is  this  great  thirst  for  power 
really  a  menace  to  humanity?  Would 
the  time  ever  come  when  the  earth, 
relieved  of  its  repelling  power,  would 
go  crashing  into  some  other  planet? 

"Now,"  said  his  friend,  "we  come  to 
the  most  interesting  of  all  of  these 
theories.  Without  the  sun,  animal  life 
could  not  exist  on  certain  planets  which 
come  within  its  range,  for  it  sends  forth 
waves  of  all  lengths,  many  of  which  are 
beyond  the  senses  of  man  to  recognize. 
The  principal  waves  of  interest  to  you 
are  the  shorter  ones,  which  produce  the 
effect  of  light  and  heat,  varying  over  a 
great  range.  Light  waves  of  various 
length  produce  different  colors  and  all 
combined  make  up  the  pure,  white  light 
which  makes  it  possible  for  you  to  see. 
As  the  waves  become  longer,  they  affect 
the  senses  by  producing  heat,  and  when 
they  become  still  longer,  they  become 
electrical  waves. 


"You  need  no  evidence  to  prove  that 
light  waves  exist  and  the  heat  waves 
will  also  exert  themselves  upon  the 
senses,  but  what  of  the  electrical  waves? 
Knowing  that  these  waves  must  exist, 
you  have  often  wondered  how  you  could 
make  use  of  them.  Science  will  probably 
discover  in  time,  that  these  very  elusive 
waves  are  the  most  important  of  all. 
They  may  find  that  these  electrical 
waves  are  making  it  possible  for  life  to 
exist  in  this  great  charge  of  electricity 
which  surrounds  you. 

"I  notice  that  you  have  what  you  call 
a  high  frequency  coil  over  there  on  your 
work  bench.  You  have  always  been 
under  the  impression  that  this  coil 
would  produce  a  high  frequency  dis- 
charge, and  as  usual  you  are  wrong. 
You  employ  a  condenser  in  this  circuit 
— the  fastest  operating  piece  of  apparatus 
known  to  man,  and  by  utilizing  some  of 
the  earth's  charge,  you  cause  this  con- 
denser to  charge  and  discharge  at  enor- 
mous speed.     Did  you  ever  look  at  this 


PRISONERS  ON  EARTH  I 

The  Wise  old  Man  of  Mr.  Pearne's 
article  gives  an  interesting  view- 
point of  man's  relation  to  the  earth 
he  inhabits. 

"  We  are  prisoners  on  this  little 
planet  and  have  no  power  to  reach 
out  from  it  and  obtain  anything 
which  is  not  already  here,"  he  says. 
"Fortunately  for  us,  man  has  not 
found  a  means  of  making  any  appre- 
ciable change  in  the  earth's  actions. 
The  small  amount  of  energy  which 
man  creates  has  no  material  effect 
compared  to  the  other  planets — but 
should  the  time  come  when  man 
does  do  something  of  a  revolutionary 
nature  in  science — look  out!  The 
earth  might  change  its  position — 
and  chaos  would  result." 


from  a  different  angle?  Did  you  ever 
stop  to  think  that  in  dealing  with  such 
high  speed  of  vibration  that  you  were 
coming  within  the  range  of  the  speed  of 
electrical  waves  from  the  sun? 

"I  don't  suppose  that  it  ever  occurred 
to  you  that  this  might  be  just  the  earth's 
charge  exerting  its  power.  I  might 
suggest  that  perhaps  the  function  of 
these  electrical  waves  from  the  sun  is 
merely  to  neutralize  the  effect  of  the 
earth's  charge,  thus  making  it  possible 
for  life  to  exist  and  other  conditions 
which  would  be  entirely  different  without 
these  waves,  therefore,  when  you  operate 
your  high  frequency  coil,  you  produce 
nothing  but  a  vibration  which  comes 
within  the  wavelength  range  of  the 
electrical  waves,  counter-acting  the  neu- 
tralizing effect  of  these  waves  upon  the 
earth's  charge,  and  this  charge  then 
begins  to  assert  itself  in  the  form  of  a 
bluish  glow  about  the  conductors  which 
are  connected  to  it  and  causing  a  tre- 
mendous discharge  across  the  terminals 
of  the  coil  when  they  are  brought  close 
together. 

"Is  this  not  a  case  of  setting  two  of 
nature's  forces  against  each  other?  If 
you  will  give  this  theory  some  thought, 
you  may  find  that  certain  electrical 
shocks   which    are    fatal    to    animal    life, 


are  caused  by  the  sudden  neutralizing 
of  some  of  these  life-giving  electrical 
waves  from  the  sun,  or  their  effect  upon 
the  body.  It  matters  little,  which  side 
of  the  earth  the  sun  happens  to  be  on, 
as  it  is  all  under  the  influence  of  these 
waves,  but  your  own  scientists  say  that 
when  the  sun  is  on  the  opposite  side  of 
the  earth,  human  life  is  at  its  lowest 
ebb,  which  may  prove  that  these  waves 
do  not  penetrate  the  earth  as  readily 
as  they  will  affect  it  from  the  outside. 
In  other  words,  their  strength  is  some- 
what reduced  by  passing  through  the 
earth. 

"Why  do  you  always  choose  the  nighi 
hours  for  transmitting  your  radio  signals? 
Because  you  find  that  signals  will  go 
much  farther  at  this  time,  because  they 
are  not  so  much  affected  by  the  sun's 
electrical  waves  when  it  is  on  the  other 
side. 

How  the  Sun  Affects  Us 

HAVE  you  ever  witnessed  the  effect 
of  the  northern  lights  at  certain 
times  of  the  year?  Where  these  demon- 
strations take  place,  the  conditions  are 
not  the  same  as  they  are  here.  Days 
and  nights  are  six  months  long  up  there 
in  the  north.  Sooner  or  later  science 
may  find  that  the  present  day  theories 
are  all  wrong  in  regard  to  these  phe- 
nomena. It  may  find  that  the  lack  of 
the  greater  power  of  the  sun's  electrical 
waves  has  much  to  do  with  these  dem- 
onstrations. 

"It  is  hardly  possible  that  because 
the  sun  is  missing  from  this  region  for 
such  long  intervals,  the  earth's  charge 
is  not  held  in  check  so  faithfully  during 
this  time,  and  that  this  charge  shows 
itself  in  the  great  bluish  glow  which 
fills  the  heavens  at  certain  times  of  the 
year.  There  are  many  other  proofs 
of  the  existence  of  electrical  waves  com- 
ing from  the  sun,  and  do  not  think  that 
it  is  necessary  for  you  to  find  a  way  to 
utilize  them — they  are  doing  their  work 
just  as  surely  as  the  light  and  heat  waves 
are  doing  theirs. 

"Remember  that  millions  of  waves 
are  coming  to  this  earth  from  the  sun, 
and  it  is  hard  indeed  to  find  the  dividing 
line  between  them.  They  are  all  mixed 
up  so  far  as  we  can  see.  A  common 
magnifying  glass  will  pass  light  waves 
through  it  and  when  properly  focused 
upon  any  combustible  material,  will  so 
concentrate  the  waves  to  a  small  pot 
and  produce  enough  heat  to  ignite  the 
material,  showing  that  near  the  dividing 
line  in  light  and  heat  waves,  they  may 
be  both.  What  other  waves  may  be 
discovered  in  thefuture  is  hard  to  imagine, 
but  rest  assured  we  know  very  little 
about  them  at  the  present  time." 

Billie  listened  closely  to  all  the  little 
han  had  to  say.  He  seemed  to  be  carried 
on  into  a  new  world.  He  began  to  feel 
a  cold  perspiration  coming  over  him, 
and  looking  over  at  the  high  frequency 
coil  which  his  friend  had  so  carefully 
explained  to  him,  he  observed  that  it 
was  beginning  to  show  the  bluish  glow 
of  which  the  old  man  had  spoken.  Sud- 
denly there  was  a  flash  across  the  ter- 
minals and  a  deafening  report  broke 
in   upon   the  conversation. 

(Turn  to  page  40) 


RADIO  AGE  for  October,  1925 


The  Magazine  of  I  he  Hour  21 


Above   is   a   view  of  the   apparatus  assembled  by  T.  Parkinson  of  the    Radio  Labora- 
tory of  the  Bureau  of  Standards  in  Washington,  D.  G,  for  conducting  tests  relative  to 
the  "fading"  of  radio  signals. 


An  Organized  War  Against   Radio   Fading 

Bureau 

of  Standards 

Engaged  in  an 

Unusual  Attempt 

to  Solve  Radio's 

Troublesome 

Enigma 

By  S.  R.  WINTERS 

THE  signals  are  being  heard  with 
such  surprising  clarity  and  in- 
tensity that  you  marvel  at  th^ 
achievements  of  radio.  Then,  wit  an 
abruptness  that  is  disconcerting,  the 
signals  weaken  rapidly  until  they  may 
become  completely  inaudible.  Mean- 
while, the  voice  of  the  speaker  or  the 
musical  strains  jf  the  orchestra  are  se  em- 
ingly  chopped  off  and  you  suffer  the 
exasperating  experience  of  having  the 
continuity  of  the  radio  program  broken. 
This  strange  phenomenon  in  radio 
reception  is  described  as  fading  or 
swinging  of  signals.  Various  theories 
have  been  advanced  in  attempts  to 
explain  this  enigma  but  thus  far  it  has 
defied  a  plausible  explanation  that  would 
point  to  the  source  of  the  trouble,  ft  is 
more  baffling,  and  at  times  more  annoy- 
ing, than  static.  Signals  from  some 
stations  are  thus  peculiarly  afflicted — 
notably,  KDKA  of  East  Pittsburgh— 
and,  not  unlike  atmospheric  disturbances, 
fading  is  more  pronounced  at  night 
than  during  the  day. 

The  Radio  Laboratory  of  the  Bureau 
of  Standards,  in  recognition  of  the 
extent  and  undermining  influence  of  this 
radio  wave  phenomenon,  recently  in- 
augurated the  most  comprehensive  inves- 
tigation of  its  kind  ever  undertaken. 
These  observations,  under  the  direction 
of  T.  Parkinson,  a  government  radio 
engineer,  will  extend  over  a  period  of 
many  months  and  have  enlisted  the  co- 
operative efforts  of  college  and  com- 
mercial laboratories,  distributed  over  a 
wide  area  of  the  United  States.  Quanti- 
tative and  qualitative  measurements  and 
possibly  directional  observations  of  fad- 
ing will  be  made. 

Unusual  experiments  require  uncom- 
mon mechanical  equipment.  This  state- 
ment is  especially  applicable  to  the 
apparatus  to  be  used  in  these  fading 
observations,  special  equipment  being 
designed  for  this  purpose.  The  truth  is, 
the   method   and   apparatus   for   making 


these  measurements  are  so  complicated 
that  the  participants  in  the  tests  are 
necessarily  limited  to  college  and  com- 
mercial laboratories.  However,  thou- 
sands of  radio  fans  and  amateurs  who 
are  not  properly  equipped  for  under- 
taking these  experiments  will  be  in- 
trigued by  the  imposing  mechanical  and 
electrical    equipment    employed. 

The  apparatus  assembled  by  T.  Park- 
inson of  the  Radio  Laboratory  of  the 
Bureau  of  Standards  is  illustrated  in 
the  photograph  and  diagram  reproduced 
with  this  article.  The  pretentious 
equipment  and  novel  arrangement  are 
inviting  enough  to  the  experimenter. 
It  is  not  conventional  in  appearance. 
For  instance,  a  super-heterodyne  radio 
receiving  set  is  shown  in  the  background 
of  the  picture  and,  despite  customary 
practice,  there  is  no  loop  or  coil  antenna 
available.  Purposely,  this  type  of  energy 
collector  is  avoided  because  in  making 
fading  measurements  directional  effects 
are  undesirable.  A  loop  or  coil  antenna 
has  pronounced  directional  character- 
istics. If  only  a  radio  receiver  with  a 
loop  antenna  is  available,  an  open  aerial 
may  be  coupled  to  the  receiving  outfit, 
the  secondary  coupling  coil  having  an 
inductance  equivalent  to  that  of  the  coil 
antenna  and   is  substituted  therefor. 

THE  type  of  receiving  set  most 
generally  used  by  observers,"  in- 
dicates Mr.  Parkinson,  "is  the  super- 
heterodyne, which  has  apparently  proved 
satisfactory.  In  one  instance  a  neutro- 
dyne  was  used  and  a  heterodyne  oscillator 
was  employed  to  produce  an  audio- 
frequency beat  note  with  the  received 
carrier,  the  beat  current  being  measured 
at  the  output  from  the  audio  stages. 
One  or  two  others  have  used  the  oscillat- 


ing detector  to  produce  the  beat  note 
and  have  similarly  measured  the  audio- 
frequency output.  One  unfortunate 
feature  of  the  latter  arrangement  is  that 
relatively  distant  generating  ('oscillat- 
ing') receivers  may  also  cause  an  audio- 
frequency beat  note  which  is  very 
effective  in  causing  galvanometer  deflec- 
tions. Such  disturbances,  though  audible 
with  the  super-heterodyne,  have  much 
less  influence  on  the  galvanometer  and 
very  often  cause  no  observable  change 
whatever. 

"It  is  also  feasible  to  use  other  types 
of  radio-frequency  amplifiers,  providing 
the  recorder  galvanometer,  with  rectifier, 
is  so  connected  as  to  measure  the  ampli- 
fied radio-frequency  current.  In  no  case, 
except  that  involving  a  definite  audio- 
frequency beat  note,  should  the  output 
of  the  audio-frequency  amplifiers  be 
measured.  Otherwise  marked  variations 
due  to  modulation  will  appear  on  the 
record  and  make  it  impossible  to  dis- 
tinguish fading  effects.  Also,  when  the 
beat  method  is  employed  it  will  be 
necessary  to  keep  the  beat  note  at  the 
same  pitch  if  comparisons  are  to  be 
dependable,  as  the  amplification  may 
vary  markedly  with  the  frequency  in 
audio-frequency     transformers." 

The  specially  designed  unit  for  observ- 
ing the  pranks  of  fading  or  swinging 
signals  is  entitled  "Type  289  Fading 
Recorder,"  and  is  obtainable  from  the 
reputable  manufacturers.  This  outfit 
includes  a  sensitive  galvanometer.  Two 
types  of  motors  are  available  for  driving 
the  clock-like  mechanism  of  the  recorder 
— an  electric  or  a  spring  motor  drive. 
The  former  is  a  60-cycle  electrically- 
driven  motor,  power  being  obtained 
by  connecting  it  to  a  60-cycle  alternating 
current     lighting     circuit.       The     spring 


22 


RADIO  AGE  for  October,  1025 


The  Magazine  of  the  Hour 


motor,  somewhat 
bulky,  requires 
winding  every  five 
or  six  minutes. 
This  type  of  mot- 
ive force,  however, 
has  the  two-fold 
advantage  of  mak- 
ing the  observer 
independent  for 
field  work  and  of 
eliminating  any 
interference  that 
might  emanate 
from  electrical 
devices.  This 
recorder  carries 
with  it  a  kymo- 
graph drum  to 
move  the  record- 
ing tape  and  a 
pen  for  writing 
down  the  observa- 
tions. This  gra- 
phic record  is  ob- 
tained by  means 
of  a  hand-operated 
lever  which  follows 
the  galvanometer 
deflections. 

"One  or  two  ob- 
servers have  made 
their  own  record- 
ing outfit,"  notes 
the  Radio  Labor- 
atory of  the  Bu- 
reau of  Standards, 
"and  some  others 
have  simply  used 
a  galvanometer 
alone  and  taken 
readings  several 
times  a  minute, 
plotting  these 
afterward  on  co- 
ordinate paper. 
Very  good  records 
showing  the  major 
variations  have 
been  secured  in 
this  way.  The 
continuous  rec- 
ord, on  the  other 
hand,  is  easier  for 

the  observer  and  shows  up  the  smaller 
fluctuations  which  may  sometimes  prove 
significant.  A  number  of  records  made 
during  the  recent  sunset  fading  tests, 
for  instance,  show  a  rapid  periodic 
swing  starting  about  fifteen  minutes 
after  the  local  sunsets  at  the  observing 
points  and  lasting  approximately  a  half 
hour.  Such  effects  may  give  a  helpful 
clue  and  would  appear  only  on  the  con- 
tinuous record.  In  this  connection  it 
should  also  be  stated  that  the  fading 
is  sometimes  so  rapid  that  a  slow-motion 
clock  drum  will  result  in  a  merging  of 
several  fluctuations  into  one  heavy  line 
on   the   record." 

USE  of  a  sensitive  galvanometer, 
having  a  full-scale  deflection  of  14 
micro-amperes,  is  recommended,  although 
some  observers  have  succeeded  in  obtain- 
ing such  amplification  that  currents  as 
great  as  160  micro-amperes  were  secured. 
This  achievement  suggests  the  possi- 
bility of  using  a  less  sensitive  recording 


TWO    ELLE_CTR.OOE1. 
"TUBE. 


FIG'  3 


BUREAU  OF  STANDARDS 

WASHINGTON,   D.  C. 


SECTION      6 


"""MM 


l!xL 


WHl.'lr: 


DRAWING  NO 

995 


The  above  chart,  prepared  by  the  Bureau  of  Standards,  gives  an  indication  of  what 
will  be  done  in  the  nation-wide  drive  to  enlist  radio  fans  in  the  war  against  exasperat- 
ing radio  signals. 


instrument  than  that  already  specified. 
However,  the  galvanometer  employed 
in  the  fading  recorder  being  described 
has  a  resistance  of  2,000  ohms  and  a 
full-scale  deflection  of  10  micro-amperes. 
In  all  cases,  it  is  recommended  that  a 
sensitive  direct-current  galvanometer  be 
employed  with  a  rectifier  in  such  a 
manner  as  to  measure  variations  in 
the  received  carrier-wave  current.  This 
Shaw  recorder,  so  called,  moves  the 
paper,  upon  which  the  observations  are 
written,  at  a  rate  of  five-eighths  of  an 
inch    per    minute. 

"A  number  of  arrangements  have  been 
experimented  with  for  rectifying  the 
radio-frequency  current  to  be  measured," 
suggests  Mr.  Parkinson,  who  is  con- 
ducting these  fading  observations  for 
the  Bureau  of  Standards.  "The  simplest 
of  these,"  he  explains,  "is  the  crystal 
detector  in  series  with  the  galvanometer 
and  the  secondary  of  a  radio-frequency 
transformer,  the  primary  of  which  is 
in  the  plate  circuit  of  a  radio-frequency 


amplifier  or  detec- 
tor tube.  Since 
changes  in  crystal 
sensitivity,  due 
probably  to  son- 
tact  variations, 
sometimes  produce 
records  very  simi- 
lar  to  fading 
curves,  this  meth- 
od is  not  altogeth- 
er dependable. 

"The  method  of 
balancing  out  the 
normal  plate  cur- 
rent of  the  detec- 
tor tube  by  means 
of  a  small  current 
supplied  by  a  sepa- 
rate battery  and 
flowing  through 
the  galvanometer 
in  the  direction  op- 
posite to  that  of 
the  'B'  battery 
Current  has  been 
tried  and  usually 
has  proved  un- 
stable. The  bal- 
ance is  difficult  to 
hold  under  the 
best  conditions 
and  with  many 
tubes  is  impos- 
sible." 

"A  more  depend- 
able arrangement 
than  either  of 
these,"  indicates 
Mr.  Parkinson  in 
describing  the 
method  employed 
at  the  Radio  Labo- 
ratory  of  the 
Bureau  of 
Standards,  "is  the 
two-electrode  elec- 
tron-tube rectifier. 
One  of  the  secon- 
dary terminals  of  a 
radio-  or  interme- 
mediate-frequency 
transformer  is  con- 
nected  to  both 
plate  and  filament  of  the  electron  tube 
while  the  other  terminal  is  connected 
through  the  recorder  galvanometer  to 
the  negative  filament.  Although  no 
'B'  battery  is  used,  there  is  a  space 
current  which  may  be  balanced  out  by 
turning  the  galvanometer  zero  adjust- 
ment until  the  instrument,  with  no  in- 
coming signals,  reads  zero. 

"The  UV-199  type  of  vacuum  tube 
is  apparently  most  satisfactory,  the  space 
current  to  be  balanced  out  being  small 
and  the  sensitiveness  being  fully  as 
great  as  that  of  a  very  good  crystal  de- 
tector when  used  in  circuit  with  the  same 
transformers  and  galvanometers.  The 
UV-201A  type  of  tube  is  also  workable 
but  the  space  current  is  so  great  that  it 
becomes  necessary  to  get  at  the  interior  . 
of  the  galvanometer  to  turn  the  zero 
control   sufficiently. 

"It    may   also    be  balanced  out  by    a 
small    series    voltage.      By  using    an  ex- 
tra   intermediate-frequency   transformer, 
(Turn  to  page        ) 


RADIO  AGE  for  October.  1925 


The  Magazine  of  the  Hour  23 


Experiments  With  Novel 
Antenna  Systems 

Solving  the  Antenna  Problem  for  the 
Portable  Radio  Receiver  by  the  Use  of 
Ingeniously-Made  Outdoor  Antennae 

By  HARRY  G.  CARROLL 


THIS  Summer's  vast  army  of  tourists 
and  vacationists  equipped  with  all 
manner  and  forms  of  portable  radio 
receiving  sets  has  shown  what  an  import- 
ant part  radio  will  play  in  the  future 
vacations  and  outings,  and  some  atten- 
tion should  be  given  to  problems  usually 
encountered  in  the  erection  and  opera- 
tion of  this  type  of  receiving  set. 

No  doubt,  the  readers  of  this  article 
themselves  have  had  this  question  in 
their  minds  more  than  once,  and  it  is 
not  an  easy  matter  for  the  layman  to 
devise  and  erect  a  truly  portable  antenna 
system  that  will  give  efficient  results 
under  such  varying  conditions  as  are 
encountered  on  a  Summer  tour,  or  at 
the    beach. 

The  first  and  most  difficult  problem 
to  confront  the  fan  is  a  suitable  support 
for  an  antenna,  high  enough  above  the 
ground  to  reach  out  and  bring  in  the 
DX  stations.  It  has  been  found  in 
heavily  wooded  sections  that  trees  and 
green  vegetation  absorb  a  vast  amount 
of  the  radiated  signal  energy  and  only 
the  super  power  stations  are  able  to 
pierce  this  barrier  and  give  satisfactory 
results  on  the  average  receiver.  To 
overcome  this  difficulty  either  a 
super  sensitive  receiver  is  necessary 
or  the  antenna  must  be  in  such  a 
position  as  to  be  above  or  away 
from  this  vegetation  as  far  as 
possible. 

Beach   Aerials   Rare 

THE  beach  offers  another  /  obsta- 
cle inasmuch  as  one  se  /  1  d  o  m 
finds  a  support  high  enou  /  gh  above 
the  ground  to  erect  an  /  antenna,  it 
is  usually  too  conge  /  sted  to  offer 
much  in  this  line  an  /  yway,  so  some 
other  means  must  /  be  resorted  to 
unless  one  has  a  /  set  that  is  sensi- 
tive enough  to  /  operate  efficiently 
with  a  loop  /  antenna.  This  does 
not  help  ma  /  tters  much,  since  a 
recent  ce  /  nsus  shows  that  the  most 
popular  portable  receiver 
is  of  the  regenerative  type, 
using  three  tubes. 
Considering  that  the  aver- 
age tourist  or  camper 
usually  employs  a  re- 
ceiving set  which 
makes    use    of    an 


How  the  box-kits  aerial  is  connected  to  the 
ground.  The  ground  pipe,  which  connects  to  the 
set,  is  likewise  connected  to  the  insulator  which  in 
turn  is  attached  to  100  to  200  feet  of  antenna  wire. 
The  kite  cord  itself,  indicated  by  "X"  in  the  draw- 
ing, should  be  able  to  stretch  out  900  to  1,000  feet. 


open  wire  aerial,  and  not  a  loop  an- 
tenna, the  writer  set  out  to  devise 
number  of  truly  portable  receiv       /     ing 
set  antenna  systems,  which  wo      /      u  1  d 
satisfactorily  meet  conditions        /     con 
fronting     the      out-of-door     «V£    radio 
listener. 

After  considerable  ex  /  penmen - 
tation  and  testing  with  /  different 
forms  of  antennae  dur  /  ing  the 
course  of  a  four  weeks'  /  radio  ex- 
perimental trip  in  /  the  North 
Woods,  the  writer  /  has  come  to 
the  conclusion  th  /  at  t  h  e  r  e  are 
three  general  ty  /  pes  of  antennae 
which  are  well  /  worth  trying 
when  out  on  a  /  touring  or  vacation 
trip  with  the  /  portable  as  part  of 
the  equipm      /      ent. 

The  fir  /  st  type  of  antenna  to 
be  desc  /  ribed  is  the  single  wire 
horizo  /  ntal  aerial,  which  is  un- 
doubt  /  edly  the  simplest  and  most 
com  /  monly  used  today,  both  at 
ho  /  me  and  in  the  field.  This  type 
particularly  adaptable  in  the 
tourist  camp  and  in  the  woods. 
It  consists  chiefly  of  a  single  wire, 
either  flexible  or  solid,  100  to  125 
feet  in  length,  both  ends  being  in- 
sulated by  means  of  strain  insulators, 
glass  porcelain  pyrex,  etc.  Height 
should  be  the  chief  object  in  the  erection 
of  an  antenna  of  this  type,  as  it  will 
be  readily  seen  that  the  farther  away 
the  antenna  wires  are  located  from 
surrounding  objects,  the  less  will  be 
the   shielding   which   they   affect. 

Although  it  is  generally  conceded 
that  the  higher  antennae  pick  up  or 
absorb  more  stray  atmospherics  or 
static  energy  than  do  the  lower  ones, 
they  are  undoubtedly  the  only  ones 
which  will  induce  sufficient  amount  of 
voltage  (EMF)  in  the  receiver  to  enable 
the  distant  stations  to  be  heard. 

Where  broadcasting  stations  are  within 
a  reasonable  distance  of  the  receiver, 
naturally  one  should  make  use  of  a 
lower  antenna,  as  less  static  will  be 
picked  up  and  the  quality  of  the  pro- 
grams will  be  better.  On  the  other 
hand,  however,  where  long  distance 
stations  are  desired,  the  higher  antenna 
is  the  only  solution  and  the  effect  which 
static  and  atmospheric  disturbances  have 
on  the  received  programs  of  course  is 
a    necessary   evil. 

Using  Tree  Supports 

AN  antenna  of  this  kind  can  be  readily 
erected    at    a    tourist    camp,    as    it 
has  been  found  that  there  nearly  always 


j  The  box-kite  aerial  is  a  most!  efficient  means  of 
erecting  i  an  impromptu  antenna.  Mr.  Carroll's 
^experiments  with  various  antennae,  during  the  past 
'Summer,  recorded  in  this  article,  should  prove  of 
immense  value  to  portable  radio  fans. 

exists  a  number  of  suitable  supports 
to  which  it  can  be  fastened.  While  in 
the  woods  trees  are  most  frequently 
made  use  of  as  supports  for  the  aerial 
wire  and  this  practice  will  prove  satis- 
factory if  a  clearing  is  picked  out  and 
the  antenna  strung  between  two  high 
trees.  The  antenna  should  be  supported 
from  the  very  top  and  this  can  be  easily 
accomplished  without  any  climbing  by 
securely  fastening  a  stone  or  other 
object  of  weight  to  a  stout  cord  and 
throwing  it  directly  over  the  top  and 
center  of  the  tree.  The  weighted  end 
of  the  cord  will  come  down,  thus  allow- 
ing the  aerial  wire  to  be  pulled  up  by 
fastening  it  to  the  other  end  of  the  cord. 
Care  should  be  taken  not  to  pull  the 
wire  up  too  far,  so  as  to  bring  it  in  con- 
tact with  any  branches.  The  same 
procedure  can  be  followed  in  elevating 
the  other  end  of  the  aerial  wire.  A 
lead-in  can  be  fastened  to  the  center 
or  at  the  end  of  the  horizontal  portion 
of  the  wire.  Only  a  very  slight  amount 
of  slack  is  necessary  in  the  flat  or  hori- 
zontal portion  of  the  antenna  in  allowing 
for  swaying  of  trees  to  and  fro  in  a 
breeze.  In  fact,  in  several  instances 
no  slack  was  allowed  at  all;  even  in  a 
heavy  wind  the  antenna  remained  well 
supported  and  no  breakage  occurred. 
It  was  noted  that  the  lighter  branches 
at  the  top  yielded  sufficiently  to  pre- 
vent any  breakage  of  the  aerial  wire 
or    support    cord. 

A  good  ground  is  equally  as  important 
as  a  good  antenna  and  under  ordinary 
conditions  an  iron  pipe  or  rod  preferably 
galvanized,  or  copper  coated,  from 
four  to  five  feet  driven  in  the  ground 
about  four-fifths  of  its  length,  will 
suffice.  The  ground  lead  running  to 
the  set  is  wrapped  around  the  pipe  in 
such  a  manner  as  to  afford  a  good 
electrical    connection. 

It  is  advisable  to  drive  the  ground 
rod  in  a  low  or  moist  spot  if  possible. 
In  the  event  that  the  ground  rod  does 
not  give  satisfactory  results,  it  may 
be  necessary  to  try  a  counterpoise. 
It  is  sometimes  the  case  that  a  good 
ground  cannot  be  established  in  this 
manner  due  to  geographic  conditions, 
as  it  has  been  found  that  large  areas 
of  earth  have  been  either  totally  or 
partially  insulated  from  the  lower  earth 
by  stratas  of  rock. 


24 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


C[TKe  Fundamental  Reason  Why 

MORE  and  BIGGER 


Technical  Difficulties 
in  Building  Super  Power 
Stations  are  Enormous; 
Some  of  the  Satisfactory 
Results   Expected  Soon 


Super-Stations 

are  COMING! 


THE  ultimate  object  which  we  hope 
to  obtain  by  super-power  broad- 
casting is,  of  course,  an  appreciable 
improvement  in  the  service  to  broadcast 
listeners.  To  what  extent  superpower 
alone  can  accomplish  this  result  has  not 
been  definitely  determined.  While  some 
phenomena  in  radio  transmission  are 
unquestionably  a  function  of  the  power 
of  the  transmitter,  other  characteristics 
are  a  function  of  the  frequency  and  the 
relative  location  of  the  transmitting 
and   receiving   stations. 

Realizing  the  limitations  of  the  present 
broadcast  service,  and  appreciating  the 
vast  amount  of  work  that  remains  to  be 
accomplished,  the  General  Electric  Com- 
pany has  established  what  is  undoubtedly 
the  largest  and  most  powerful  broad- 
casting transmitting  laboratory  in  the 
world  devoted  to   development  work. 

This  laboratory  is  designed  to  permit 
a  thorough  study  of  radio  transmission 
in  general,  and  broadcast  transmission 
in  particular.  It  provides  equipment 
for  obtaining  the  transmission  char- 
acteristics of  wavelengths  between  5 
meters  and  3000  meters,  at  powers  up 
to  100  kw.  In  addition,  there  have 
been  provided  sufficient  antenna  struc- 
tures so  that  the  best  type  of  antennas 
or  radiators  can  be  determined  for  the 
various   wavelengths. 

A  Mammoth  Enterprise 

THE  laboratory  occupies  54  acres  of 
of  land,  and  consists  of  13  buildings, 
three  towers  300  feet  high,  one  tower  150 
feet  high  and  a  number  of  smaller  towers 
ranging  from  60  to  100  feet  in  height. 
From  and  between  the  towers  is  arranged 
a  network  of  antennas  with  which  it  is 
hoped  to  secure  fundamental  data  on 
the  most  efficient  antenna  for  a  given 
wavelength  and  power. 

To  return  to  the  subject  of  what 
super-power  can  do  for  broadcast 
reception:  First,  it  is  obvious  that 
increased  power  at  the  transmitter 
will  provide  increased  energy  at  the 
receiving  station,  thus  raising  the 
level  of  the  signal  above  that  of  the 
noise.  This  should,  to  some  extent, 
tend  to  decrease  the  effect  of  static 
and  other  disturbances;  second,  it 
may  appreciably  decrease  the  extent 
to  which  fading  interferes  with  re- 
ception; third,  it  may    Increase    the 


range  of  the  transmitter  so  that 
programs  can  be  satisfactorily  re- 
ceived over  a  greater  area,  and  hence 
provide  better  service  both  day  and 
night. 

At  the  present  time,  when  the  word, 
"super-power"  is  applied  to  so  many 
projects,  it  is  perhaps  difficult  for  the 
broadcast  listener  to  fully  appreciate  the 
technical  difficulties  that  must  be  over- 
come in  building  a  transmitter  of  this 
size.  Some  idea  of  the  problem  may  be 
gained  from  the  fact  that  such  a  trans- 
mitter must  be  capable  of  receiving  an 
extremely  small  amount  of  sound  energy, 
converting  it  to  electrical  energy,  and 
amplifying  it  fifty  thousand  million 
times   without   distortion. 

Some  apprehension  has  been  felt,  and 
suitably  so,  by  the  Department  of  Com- 
merce, as  to  the  use  of  appreciably  higher 
power  for  broadcasting,  believing  that 
it  might  result  in  the  program  of  a  super- 
station  crowding  out  the  programs  of 
the  lower  power  stations,  particularly 
in  the  vicinty  of  the  station  itself. 

For  this  reason,  the  super-power  sta- 
tion of  the  General  Electric  is  located 
several  miles  from  the  city  of  Schenec- 
tady, so  that  the  intense  field,  in  its 
immediate  vicinity,  will  not  interfere 
with  the  reception  of  other  programs 
by    the    inhabitants    of    Schenectady. 

It  is  also  for  this  reason  that  the 
present  series  of  tests  are  being  carried 
on  at  rather  unseasonable  hours,  since 
the  license  for  the  station  is  an  experi- 
mental one,  and  does  not  permit  broad- 
casting during  the  normal  broadcasting 
hours.  The  Company  is  in  this  way 
co-operating  with  the  Department  of 
Commerce  in  an  effort  to  get  exact  data 
on  super-power  broadcasting  before  it 
is  carried  on  during  the  earlier  hours. 

The  reports  received  up  to  the  present 
time  from  nearby  as  well  as  distant 
points,  indicate  that  no  interference  is 
being  caused  by  the  use  of  super-power. 
In  fact,  many  reports  have  commented 
on  the  extreme  sharpness  of  the  trans- 
mission. 

It  should  be  remembered  that  the 
current  in  the  receiving  antenna  is  not 
directly  proportional  to  the  power  of 
the  transmitter,  but  is  proportional  to 
the  amperes  in  the  transmitting  antenna, 
so  that  the  power  of  the  transmitter 
must  be  increased  four  times  to  double 


the  current  in  the  receiving  antenna  or 
loop.  This  fact  is  mentioned  for  the 
benefit  of  those  who  might  otherwise 
expect  a  signal  strength  greater  than 
the  facts  warrant. 

It  is  hoped  and  fully  expected  that 
the  tests  and  development  work  now 
being  carried  on  will  carry  radio  an 
appreciable  step  forward  in  overcoming 
those  things  which  are  undesirable  in 
present  day  broadcasting.  No  one 
doubts  but  that  these  problems  will 
eventually  be  solved  to  the  entire  satis- 
faction  of  the  broadcast  listener. 

A  Systematic  Research 

\  RADIO  development  laboratory  for 
■£*■  research  on  wavelengths  from  5 
meters  to  3,000  meters  with  power  from 
5  watts  to  100  kilowatts,  has  been  con- 
structed on  a  54  acre  plot,  two  miles 
southwest  of  Schenectady,  by  the  Gen- 
eral Electric  Company. 

This  work  of  radio  development  is 
undertaken  for  the  purpose  of  making  a 
systematic  study  of  transmission  phe- 
nomenon. Because  of  meager  data, 
there  is  one  group  of  scientists  advocat- 
ing super-power  as  the  remedy  for  exist- 
ing broadcasting  defects;  another,  low 
power  short  wave  transmission  to  ac- 
complish the  same  results;  another 
medium  power,  long  wave  transmission 
and  many  different  types  of  antenna 
systems  are  recommended,  including 
the  reflector,  vertical,  horizontal  and 
angular. 

On  the  plot  near  Schenectady  are  one 
brick  building,  60x100  feet,  and  four 
smaller  frame  buildings  in  which  are 
housed  transmitters.  There  are  three 
steel  towers  each  300  feet  high  arranged 
in  the  form  of  a  triangle.  This  arrange- 
ment permits  the  construction  of  many 
different  types  of  antennae.  A  fourth 
steel  tower  150  feet  high  is  used  for 
smaller  antenna  structures.  Three  80 
foot  wood  masts  support  the  antenna 
now  being  used  for  the  109  meter  trans- 
mitter. 

The  largest  building  houses  the  power 
equipment,  high  voltage  rectifiers  and 
amplifying  and  modulating  equipment 
for  the  stations.  There  are  three  recti- 
fiers each  having  a  capacity  of  150  kw. 
at  15,000  volts.  These  rectifiers  convert 
the  alternating  current  supplied  to  the 
(Turn  to  page  57) 


RADIO  AGE  for  October.  1925 


What  the  Broadcasters  are  Doing  25 


At  Last  Sally  Is  Found! 


After  years  of  tireless  search,  we've  solved  the  question  of  what's  become 
of  Sallyl  Word  comes  from  California  Radio  Stations  that  "Sally  Bell," 
shown  above  in  an  exceedingly  piquant  pose,  is  capturing  the  hearts  of  the 
broadcast  listeners  by  her  eccentric  programs  with  her  trusty  "uke."  She 
appears  most  consistently  at  the  Hollywood  and  Los  Angeles  stations. 

fPhoto  by  Witzel) 


26 


RADIO  AGE  for  October,  1925 


What  the  Broadcasters  are  Doing 


Wkat  tke 
Broadcasters 
Doing 


are 


Radio  Puts  Army,  Navy  and 
Marine  Bands  on  Map 

WASHINGTON,  D.  C— For  years 
the  crack  musical  organization  of  the 
country  has  been  the  U.  S.  Marine  Band, 
which  began  as  a  fife-and-drum  corps  in 
1798  and  came  into  fame  with  Sousa  as 
its  leader.  More  latterly  it  has  been  ably 
directed  by  Capt.  William  H.  Santel- 
mann.  The  Marine  Band  has  led  more 
historic  military  reviews  and  inaugural 
parades  than  any  other  band  in  the 
United  States.  This  red-coated  organiza- 
tion has  formed  a  picturesque  background 
for  social  functions  at  the  White  House. 

Sharing  honors  with  the  Marine  Band 
during  the  past  few  years  have  been  the 
Army  Band,  sponsored  by  General  Per- 
shing, and  the  Navy  Band.  When  Gener- 
al Pershing,  as  head  of  the  American 
Expeditionary  Force,  returned  from 
Europe  at  the  conclusion  of  the  war, 
after  hearing  the  famous  Garde  Republi- 
caine  Band  of  France  and  the  Brigade  of 
Guards  Band  of  the  British  Army,  he 
set  about  having  a  band  organized  from 
army  bands  in  this  country  that  would 
equal  these  famous  organizations. 

However,  until  radio  came  in,  there 
was  a  tremendous  handicap  in  Washing- 
ton, their  home,  with  regard  to  the 
Marine,  and  Army  and  Navy  bands.  It  was 
because  they  were 
so  seldom  heard.  \ — 

True,  duringthe 
Summer  months 
there  were  con- 
certs on  the  White 
House  lawn,  the 
Capitol,  and  other 
places.  Again  there 
were  concerts  in 
the  Marine  Bar- 
racks, so  remotely 
located  as  to  be 
difficult  to  find  and 
in  an  ancient  band 
stand  in  Potomac 
Park,  a  mile  from 
a  car  line  and  al- 
most inaccessible 
to    the   visitor. 

Radio,  however, 
has  changed  it  all. 
The  three  great 
service  organiza- 
tions are  now  reg- 
ularly heard  on 
the  air  and  by  the 
hundreds  of  thou- 
sands of  citizens 
throughout  the 
country. 


The  attentive  Jace  above  belongs  to  Frank  S.  Lane, 
regular  announcer  at  KFR  V,  Bristow,  Okla.  He  is  a 
great  favorite  among  the  fans  in  the  Middle  West, 
chiefly  because  his  prime  characteristic  in  announcing 
is — brevity.      More   power    to    him! 


WBBM  Starting  Program 
For  Kiddies 

STARTING  daily  at  5:30  p.  m., 
Chicago  Daylight  Saving  Time, 
WBBM  is  running  a  daily  program  for 
the  kiddies  from  their  Broadmoor  Hotel 
Studio. 

It  is  in  the  form  of  a  club  meeting, 
run  by  Joy-Digger,  Tiny  Dave,  Uncie 
Charlie,  and  various  other  performers. 
The  club  is  known  as  the  Joy-Digger 
Club  of  WBBM,  and  the  motto  is:  "Dig 
a  little  joy  out  of  everything  every  day; 
it's  there  if  you  only  dig  deep  enough." 

The  programs  of  the  club  will  consist 
of  songs,  stories  and  instrumental  num- 
bers, many  of  them  put  on  by  the  kiddies 
themselves.  One  program  a  week  will 
be  taken  over  by  the  various  members  of 
the  Boy  Scout  Troops  of  Rogers  Park. 


W-K~i 


No,  this  is  not  a  scene  along  the  European  Riviera;  it  is  just  a  view  of  the  coast-line 
which  will  soon  be  the  home  of  KT NT,  about  to  go  on  the  air  at  Muscatine,  Iowa.  KT NT 
is  said  to  be  one  of  the  most  beautifully  located  stations  in  America.  Its  towers,  location 
of  which  is  indicated  by  the  arrow  in  the  picture,  will  tower  150  feet  above  the  Mississippi, 
with  a  view  of  50  miles  in  all  directions. 


Editor  of  Radio  Age  on 
Air  from  WLS 

FREDERICK  SMITH,  editor 
of  RADIO  AGE,  delivered  an  ad- 
dress to  the  radio  public  through  the 
microphone  of  WLS,  the  Sears-Roebuck 
station,  from  its  Hotel  Sherman  studio 
in  Chicago,  recently.  Excerpts  from  his 
talk  are  as  follows: 

"Several  years  ago,  when  radio  broad 
casting  was  in  the  infancy  of  its  develop- 
ment I  made  a  talk  about  the  new 
art  from  this  same  room.  After  the 
luncheon  was  over  a  good  Rotarian 
brother  came  to  me  and  said: 

"  'Do  you  really  believe,  Smith,  that 
this  radio  fad  is  going  to  be  permanent?' 

"I  told  him  that  in  my  opinion  radio 
would  grow  to  be  a  social  and  economic 
factor  far  more  important  than  he  or  I 
could    at    that    time    imagine.      If    that 
good   brother   is   present   today    I    want 
to  call  his  attention  to  the  fact  that  radio 
is  now  about  the  most  continuously  per- 
manent thing  we  have  around  the  house, 
with  the  possible  exception  of  the  tax  col- 
lector.    We  get  the  setting  up  exercises  in 
the  early  morning  to  keep  us  thin.    Later 
the  cooking  lessons  tell  us  how  to  eat  and 
wax  fat.   The  forenoon  brings  us  the  mar- 
kets and  household  hints.     Noon  brings 
the  organ  recitals  and  other  features.     In 
the  afternoon  are 
the    concerts    and 
general  programs. 
At   twilight   the 
bedtime   stories 
and  lullabyes  and 
from  then  on  there 
is  jazz  until  such 
hours  as  all  honest 
people    should    be 
abed.    Wake  up  in 
the  middle  of  the 
night  if  you  choose 
and  tune  in  on  536 
meters   and   you 
can  hear  the  World 
Crier  telling  about 
the  latest  develop- 
ments in  the  Mor- 
oroccan    situation. 
I'll    say    radio    is 
permanent!     It  is 
so  permanent  that 
it  makes  a  noise  on 
our  so-called  silent 
Monday    nights. 
But  when  one  of  us 
tunes    in    another 
tunes  out  and  there 
is    always    some- 
one listening." 


RADIO  AGE  for  October,  1925 


What  the  Broadcasters  are  Doin"  27 


Now  we 
Have 


BELASCO 


Radio' 


The  Qirl  Behind  the  Scenes  at  Station  WTAM 


HONORS  just  naturally  gravitate 
toward  the  deserving  and  that  is 
why  Miss  Ruth  King,  of  Cleve- 
land, Ohio,  is  claiming  the  attention  and 
admiration  of  broadcasting  stations  and 
broadcast  listeners  alike,  and  has  been 
called  "The  Belasco  of  Radio."  Those 
famous  "Nite  Cap"  programs  that  are 
broadcast  on  the  first  Saturday  of  each 
month  from  WTAM;  the  luncheon 
concerts  that  are  on  the  air  from  this 
station  every  day  except  Sunday;  the 
Wednesday  evening  dinner  hour  of  music 
— all  the  details  of  these  entertaining 
programs  are  arranged  by  the  little  lady 
in  the  accompanying  photograph.  And 
now  she  has  been  called  upon  to  serve 
on  the  Program  Committee  of  Cleveland's 
first  annua]  radio  exposition  which  is  to 
be  held  in  the  public  auditorium  from 
November  7th  to  the  15th  of  this  year. 
The  holder  of  many  medals  for  tennis 
championship,  editress  of  a  society  paper 
devoted  to  country  club  affairs,  an 
accomplished  musician  and  composer, 
Ruth  King  has  crowded  a  host  of  success- 
ful efforts  into  a  few  short  years  of  public 


By  P..  A.  PRICE 


life.  However,  it  would  seem  that  the 
young  lady  was  destined  to  be  a  Program 
Director  for,  when  the  Cleveland  Plain 
Dealer  opened  its  studio  for  Station 
WTAM  it  was  Miss  King  who  was  called 
upon  to  arrange  the  programs  broadcast 
from  that  remote  control  equipment. 
Then  the  Plain  Dealer,  with  other  Cleve- 
land newspapers,  gave  up  association 
with  the  radio  stations  and  the  Euclid 
Music  Company  took  up  the  good  work 
and  placed  Miss  King  in  charge  as  Pro- 
gram Director  of  their  station  that  is 
operated  by  remote  control  from  WTAM. 
It  was  a  choice  well  made,  for  the  young 
lady's  programs  were  a  success  from  the 
first. 

We  who  listen  in  have  small  idea  of 
the  effort  involved  in  arranging  for  a 
daily  program  or  for  such  special  feature 
programs  as  are  offered  by  the  "Nite 
Caps."  If  Miss  King's  expression  is 
just  a  trifle  pensive  it  may  be  due  to  a 
natural  worry  as  to  whether  some  par- 


ticularly desired  artist  will  appear  on 
schedule  time.  Artists  are  proverbially 
tempermental  and  this  applies  to  their 
punctuality  as  well  as  their  dispositions. 
Once  upon  a  time  this  did  happen  in 
the  studio  and  Miss  King,  in  looking 
about  for  the  next  artist  to  appear, 
found  herself  deserted  and  alone.  The 
situation  was  tragic,  but  instead  of  losing 
her  head  Miss  King  used  it  and  calmly 
announced  that  the  next  number  would 
be  a  piano  solo  by  "Miss  Betty  Parker" 
and  then  as  calmly  seated  herself  at  the 
piano  and  provided  the  solo  herself. 
Since  then  "Miss  Betty  Parker"  has 
played  several  accompaniments,  thus 
proving  that  a  dual  personality  is  very 
handy  to  have  in  a  broadcasting  studio. 
Ruth  King  is  building  a  big  future  for 
herself  by  developing  her  administrative 
ability.  With  youth,  energy,  ambition 
and  ability  to  drawn  upon,  Ruth  King 
will  go  far  in  the  field  of  radio  broad- 
casting and  with  her  will  go  the  best 
wishes  of  a  legion  of  broadcast  listeners 
who  look  to  her  for  their  entertainment 
and  have  yet  to  be  disappointed. 


28  RADIO  AGE  for  October,  1925 


"The  Town  Crier  of  the  Day"  at  KNX,   "The  Voice  of  Hollywood,"  with 
Little  Jean,   5-year-old  mute  girl  who  is  learning  to  talk  and  hear  by  radio. 


What  the  Broadcasters  are  Doing 

'The  Radio  Boy  Wonder" 

of 
Hollywood       5 

How  a  Mere  Youngster  Started 
a  Radio  Station  in  America's 
Most  Interesting  City,  Which 
Is  Destined  to  be  America's 
Most  Interesting  Contribution 
to  the  Radio  Art 

B;y  C.  CLYDE  COOK 


SITUATED  in  the  "Heart  of  Holly- 
wood," Station  KNX,  the  Los 
Angeles  Express,  is  generally  con- 
ceded to  be  one  of  the  most  popular  sta- 
tions on  the  entire  Pacific  Coast,  because 
of  the  clarity  of  reception,  superior  tone 
and  the  high  standard  of  programs  that 
bring  within  their  scope  the  interests  of 
all  radio  listeners-in. 

"So  This  Is  Hollywood!"  can  certainly 
be  applied  to  Station  KNX,  for  this 
station  has  the  distinction  of  broadcast- 
ing more  screen  talent,  perhaps,  than 
any  other  station  in  America. 

Because  of  its  convenient  location 
to  the  homes  of  many  of  the  world's 
most  famous  artists,  musicians  and 
people  of  national  and  international 
fame,  who  naturally  accept  KNX  as 
their  "home  station,"  they  are  irresist- 
ibly attracted  to  the  KNX  microphone 
by  the  quality  standards  of  broadcasting 
maintained  there.  And,  though  the 
station  will  be  only  a  year  old  in  October, 
KNX  already  has  a  greater  following 
of  radio  fans  than  stations  many  years 
its  senior. 

And  who  was  responsible  for  this  great 
station?  An  admirably  gracious  young 
man  of  about  thirty  years  was  instantly 
pointed  out  as  the  founder  of  this  unique 
institution.  But,  try  as  we  might,  we 
could  not  get  Guy  C.  Earle,  nephew  of 
Mr.  E.  T.  Earle  (former  owner  of  the 
L.  A.  Express),  to  divulge  any  informa- 
tion concerning  his  own  participation 
in  KNX.  From  other  sources  we  learned 
that  Guy  C.  Earle  attended  the  common 
schools  in  Oakland,  and,  after  graduat- 
ing from  the  University  of  California,  he 


took  a  postgraduate  course  in  Columbia. 
Recently  Guy  C.  Earle  took  over  the 
management  of  the  Los  Angeles  Express, 
but  the  station  KNX  will  ever  remain 
his  chief  concern,  for  there  is  something 
so  human  and  vital  about  this  young 
newspaper  magnate  that  he  derives  more 
joy  from  broadcasting  cheer-inspiring 
programs  on  the  air  than  from  hoarding 
up  more  of  this  world's  goods. 

A    Real    Miracle 

ONE  of  the  most  trenchant  reasons 
why  Mr.  Earle  derives  great  pleasure 
from  this  station  is  because  a  modern 
miracle  is  being  wrought  at  KNX,  doing 
what  the  science  of  medicine  and  surgery 
could  not  do — give  hearing  and  speech 
to  a  little  girl,  born  deaf  and  dumb.  Mr. 
E.  J.  Albright,  Town  Crier  of  the  Day 
Watch,  detailed  the  miraculous  cure 
being  perfected  by  means  of  the  radio. 

"When  this  little  girl,  Jean  Marie  Mac- 
Williams,  first  placed  the  head  phones 
on  her  ears  she  caught  the  sounds,  and 
began  to  give  audible  proof  of  it  in  trying 
to  repeat  some  of  the  major  chords. of 
sound,  with  their  variations.  Taking 
her  to  an  eminent  physician  they  learned 
that  Jean  Marie  possessed  a  very  un- 
common sense,  'bone  conduction;'  i.  e., 
the  bone  picks  up  tone  and  it  registers 
by  vibrating  against  the  auditory  nerve. 

"Later  her  parents  brought  little  Jean 
Marie  to  the  KNX  station  and  finally  I 
evolved  a  plan  by  which  I  believe  Jean 
Marie  will  succeed  in  overcoming  her 
handicap.  I  proceed  to  ask  her  very  simple 
questions  and  she  has  progressed  so  well 
that  she  usually  answers  correctly,  and   I 


encourage  her  in  every  way  possible." 
It  was  too  apparent  that  this  announcer 
was  gifted  with  a  magnanimous  heart. 
The  demonstration  with  this  once  deaf 
and  dumb  little  girl  was  astounding,  and 
yet  it  only  proves  what  marvelous  things 
can  be  accomplished  by  radio.  This 
much  the  "Radio  Philosopher,"  G. 
Allison  Phelps,  now  the  Town  Crier  of 
the  Night  Watch,  conceded  with  his 
infectious  smile.  The  "Radio  Phil- 
osopher" has  a  magnanimous  heart, 
also,  and  his  philosophy  of  life  is  abso- 
lutely an  inspiration  to  all  who  hear  his 
lectures  over  the  radio.  When  he  lost 
his  devoted  mother  five  years  ago  he 
felt  for  a  time  that  life  was  not  worth 
living,  but  finally  he  worked  out  a  philos- 
ophy which  has  brought  many  a  radio 
convert  out  of  the  "dumps"  just  as  it 
did  Phelps. 

The  "Radio  Philosopher"  has  become 
so  in  demand,  since  his  lectures  delivered 
over  KHJ,  the  Los  Angeles  Times,  that 
station  KNX  suddenly  annexed  him 
to  their  present  talented  staff,  of  which 
Carrie  Preston  Rittmeister,  most  able 
accompanist  and  program  manager,  is 
one  of  the  foremost  members.  Mrs. 
Rittmeister  also  came  from  station  KHJ, 
where  she  had  served  in  the  same  capac- 
ity and  observed  Queen  Titania  deliver 
her  initial  program  with  her  father,  the 
Sandman. 

No  program  arranger  ever  guarded 
the  standards  of  their  programs  more 
zealously  than  does  Mrs.  Rittmeister. 
This  can  be  easily  attested  by  the  thou- 
sands of  radio  fans  throughout  the  United 
States,    who   are   so   fortunate   as   to   be 


RADIO  AGE  for  October,  1925 


What  the  Broadcasters  are  Doing 


29 


able  to  tune  in  on  her  incomparable 
programs.  And  here  is  a  sample  of  the 
pleasing  variety  of  her  inimitable  pro- 
grams: 7:30  a.  m.  KNX  morning  gym, 
directed  by  J.  C.  Casey,  physiotherapist. 
8  a.  m.,  inspirational  talk  and  morning 
prayer;  9  a.  m.,  time  signals  from  Wash- 
ington; 10  a.  m.,  Town  Crier  of  the  Day's 
morning  message;  10:30  a.  m.,  Kate 
Brew  Vaughan,  director  of  household 
economics  department  of  Evening  Ex- 
press, gives  lecture;  11  a.  m.,  nature  talk; 
12  m.  to  1  p.  m.,  VVurlitzer  organ  recital; 
3  p.  m.,  talk  by  Chef  de  Cuisine;  4  p.  m., 
Metro-Goldwyn-Mayer  Studio  program. 
5  p.  m.,  market  reports;  5:30  p.  m.  to 
6:15  p.  m.,  sport  talk  by  Sid  Ziff,  sporting 
editor  of  Express;  5:55  p.  m.,  the  Town 
Tattler;  6:15  Alder  Travelogue;  6:30 
p.  m.  to  7  p.  m.,  Atwater  Kent  orchestra; 

7  p.  m.  to  7:30  p.  m.,  Ambassador  Hotel 
concert  orchestra;  7:30  to  8  p.  m.,  talk 
on    the    Movies  by    Norma    Talmadge; 

8  to  9  p.  m.,  Venice  of  America  band; 
Town  Crier  of  the  Night  Watch;  9  to  10 
p.  m.,  Abe  Lyman's  Cocoanut  Grove 
orchestra;  10  to  11  p.  m.,  Hollywood 
night,  with  celebrated  stars  being  intro- 
duced; Town  Crier  of  the  Night  Watch. 

And  thus  concludes  an  all-day  program 
of  greatly  diversified  entertainment,  in- 
struction, inspiration,  etc.,  the  equal  of 
which  is  hard  to  find  on  any  other  broad- 
cast program.  Another  reason  for  the 
unusual  quality  of  the  KNX  programs 
is  the  famed  string  orchestra  of  Calmon 
Luboviski,  who  was  born  in  Chicago 
of  Russian  parentage,  and  later  became 
the  one  and  only  pupil  of  the  interna- 
tionally famous  violinist,  Ference  de 
Vecsey.  After  eight  years  of  intensive 
study  under  this  master's  guidance 
Luboviski  returned  to  America,  en- 
trusted with  the  master's  secrets  of  tone 
and  technique,  where  he  electrified  large 
audiences  in  the  largest  symphony  or- 
chestras of  the  United  States. 

A  Tireless  Worker 

SINCE  last  September  Luboviski  has 
filled  two  hundred  concert  engage- 
ments, and  this  tireless  genius  is  now 
broadcasting  exclusively  over  the  KNX 
broadcast  station  in  conjunction  with 
the  world-famed  Luboviski  trio,  consist- 
ing of  Mischa  Gegna,  cello  soloist,  Joseph 
Vecsei,  pianist  soloist,  and  Calmon 
Luboviski,  violin  soloist.  And  Lubo- 
viski's  Russian  string  quartette  needs 
no  introduction  to  radio  fans  throughout 
the  United  States,  as  they  have  broad- 
cast from  several  hundred  stations  in 
the  few  short  years  of  their  existence. 

Another  shining  star  in  KNX's  con- 
stellation of  radioland's  luminous  firma- 
ment is  Raquel  Nieto,  coloratura  soprano, 
one  of  the  most  marvelous  voices  heard 
in  radioland,  and  discovered  by  station 
KNX.  She  has  been  acclaimed  by  her 
most  discriminating  listeners  as  a  future 
Galli  Curci,  and  in  view  of  the  fact  that 
Miss  Nieto  is  but  twenty  years  of  age 
this  is  quite  commendable.  Hailing 
from  Mexico  City,  this  titian-haired, 
blue-eyed  Spanish  artist  has  a  great 
future  in  store  for  her. 

When  Norma  Talmadge  appears  in 
the  KNX  studio  in  the  near  future  and 
broadcasts   the    marvels   of   the    moving 


Miss  Marguerite  Rickard,  lyric  soprano  of 
KNX,  and  exceedingly  easy  to  look  at. 
Miss  Rickard's  brother,  Vernon  Rickard,  is 
announcer  at  WGN,  Chicago,  so  it  must 
run  in  the  family. 

picture,  and  portrays  her  extensive  work 
in  the  cinema  drama,  radio  fans  through- 
out the  United  States  will  again  experi- 
ence one  of  the  many  innovations  which 
has  made  KNX  the  peer  of  all  stations 
which  specialize  in  studio  talent.  Miss 
Talmadge  has  a  clear,  bell-like  voice, 
and     the    enthusiasm     with     which     she 


enters  into  these  broadcasting  programs 
is  actually  an  inspiration  to  those  who 
are  fortunate  enough  to  hear  her. 

Miss  June  Pursell,  heralded  as  the 
KNX  Radio  Girl,  and  who  has  now  gone 
on  the  Orpheum  Circuit  of  Vaudeville 
to  entertain  vast  audiences  with  her 
resonant  voice,  possesses  such  a  deep, 
masculine  voice  that  she  has  often  been 
mistaken  for  a  male  broadcaster.  How- 
ever, this  only  goes  to  prove  that  Mrs. 
Rittmeister  is  ever  vigilant  to  gather 
into  the  fold  of  KNX  station  a  galaxy 
of  stars  which  will  give  the  thousands 
of  radioland  listeners-in  the  greatest 
possible  variety  of  talent,  coupled  with 
the  best  obtainable  degree  of  high  stan- 
dard of  quality. 

KNX  is  on  the  air  more  hours,  perhaps, 
than  any  other  station  in  the  United 
States,  since  they  start  the  day  off  with 
gym  instruction  at  7:30  in  the  morning, 
and  hundreds  of  letters  pouring  into  the 
studio  daily,  attest  the  value  this  physical 
exercise  has  been  to  many  converts  of 
radioland.  And  few  stations  can  com- 
pare with  KNX  for  variety  of  program. 
So  if  you  want  a  real  air-fest,  every  hour 
of  the  day,  just  tune  in  on  station  KNX, 
the  Los  Angeles  Express,  Hollywood, 
California. 


Guy  C.  Earle,  Jr.,  the  "Boy  Wonder  of 
Hollywood"  who  is  manager  and  owner  of 
KNX,  the  Los  Angeles  Express  Station. 
It  is  due  to  his  efforts  that  KNX  has  become 
one  of  the  most  widely  known  radiocasts  in 
the  country. 


Radio  Problems  Explained  at 
Convention 

CHICAGO,  ILL.— Radio  interference, 
the  development  and  use  of  the  radio 
vacuum  tube  and  design  of  radio  re- 
ceivers were  subjects  touched  upon  at 
the  sessions  of  the  Third  National  Con- 
vention of  the  American  Radio  Relay 
League  at  the  Edgewater  Beach  Hotel  in 
this  city.  Outstanding  figures  in  each  of 
three  divisions  of  radio  science  presented 
papers  for  the  information  of  the  several 
hundred  transmitting  radio  amateurs 
attending  the  gathering. 

Professor  W.  J.  Williams  of  Rensselaer 
Polytechnic  Institute  and  director  of 
radio  broadcasting  station  WHAZ  of 
Troy,  N.  Y.,  covered  the  information  now 
available  about  the  various  types  of 
radio  interference.  He  told  of  his  ex- 
periences with  power,  telephone  and 
telegraph  companies  in  attempting  to 
run  down  radio  interference.  He  touched 
upon  the  influence  of  the  vast  number  of 
power  lines  in  the  country,  pointed  out 
some  of  the  difficulties  experienced  with 
electrical  appliances  and  vehicles,  such 
as  trolley  cars  and  electric  railroads. 

A  detailed  explanation  showed  that  all 
of  these  sources  were  contributing  some- 
thing to  the  vast  total  of  interference. 
Prof.  Williams'  paper  was  based  upon 
perhaps  the  most  exhaustive  research 
made  on  the  subject.  Working  with  the 
various  other  users  of  electrical  energy, 
he  has  come  into  contact  with  practically 
every  known  cause  of  interference. 

J.  C.  Warner,  in  charge  of  small  tube 
development  at  the  General  Electric 
Company  Research  Laboratory,  drew 
upon  his  store  of  experience  gathered  in 
the  years  during  which  vacuum  tubes 
have  made  such  tremendous  strides. 
He  announced  the  completion  of  work 
tending  toward  a  standardization  of  tube 
bases  and  sockets,  a  matter  that  has  in 
the  past  made  necessary  structural  alter- 
ation to  meet  many  desired  changes. 

The  demand  for  a  dry  battery  tube 
that  will  supply  sufficient  undistorted 
audio  frequency  to  operate  a  large  loud 
speaker  has  been  met,  Mr.  Warner  said. 


30 


RADIO  AGE  for  October,  1925 


What  the  Broadcasters  are  Doing 


How 

Super-Station 
KYW  Achieves 


The  upper  photo  shows  KYWs  station  along 
the  east  watt,  looking  south.  To  the  right  are 
seen  the  control  board,  modulator  panel,  oscillator 
panel  and  tuning  panel.  In  the  circle  is  Walter 
C-  Evans,  chief  engineer  of  the  new  KYW. 


Quality, 
Reliability, 
and  POWER 


KDKA'S  SISTER  STATION  OPENS  ON  CONQRESS  HOTEL,  CH1CAQO 


THE  principal  considerations  striven 
for  in  the  design  and  installation 
of  the  new  Westinghouse  Station 
KYW  on  the  roof  of  the  Congress  Hotel 
were  perfection  of  quality,  reliability, 
and  reserve  power.  The  resources  and 
best  engineering  skill  of  a  great  company 
have  gone  into  the  new  equipment  in 
order  that  the  vocal  solo  or  complex 
orchestration  may  be  turned  over  to  a 
discriminating  public,  identical  with  the 
original  sound. 

Years  of  experience  in  the  design  of 
electrical  apparatus  is  apparent  in  the 
well  arranged  panels,  the  easily  accessible 
units  with  everything  in  duplicate  so 
that  program  interruptions  due  to  elec- 
trical causes  may  be  reduced  to  an  abso- 
lute minimum. 

Considerable  more  power  is  provided 
for  than  will  ever,  in  all  probability,  be 
needed  for  ordinary  broadcasting.  This 
is  a  desirable  feature,  for  it  is  a  better 
operating  proposition  to  run  a'  large 
piece  of  electrical  equipment  at  a  frac- 
tion of  its  capacity  than  to  overload  a 
small  installation.  This  will  leave  a 
large  margin  of  reserve  power  in  case  of 
national  emergencies,  paralysis  of  tele- 
graph and  telephone  lines  or  similar 
contingencies. 

To  get  a  good  working  idea  of  this 
Leviathan  of  the  radio  field,  we  will 
begin  with  the  primary  source  of  power 
and  follow  it  through  to  the  antenna. 

Current  at  4400  volts  is  obtained  from 


By  Walter  Q  Evans 


the  local  public  service  company  over 
two  separate  transmission  lines  from 
different  generating  stations.  This  gives 
100%  insurance  against  power  line 
interruptions.  A  100  kilowatt  trans- 
former sub-station  has  been  built 
in  the  basement  of  the  hotel  where  the 
transmission  lines  are  stepped  down  to 
220  volts  and  carried  through  large 
capacity  cables  to  the  radio  station  on 
the  roof.  These  are  connected  with  a 
power  distribution  board  or  feeder 
panel  through  which  all  of  the  different 
pieces  of  apparatus  draw  their  source 
of  power.  This  panel  also  carries  suit- 
able cut-outs  to  open  the  circuits  and 
shuts  off  the  current  should  accidents 
occur  to  the  different  machines. 

Next  in  line  is  the  contactor  panel, 
which  does  the  thinking  for  the  set 
(and,  if  necessary,  for  the  operator). 
It  is  so  arranged  that  the  operator  need 
only  press  one  small  push  button  and 
in  slightly  over  10  seconds  the  whole 
station  gets  under  way.  The  push  button 
first  energizes  the  water  pump  which 
forces  a  stream  of  cold  water  through 
the  jackets  of  the  tubes.  When  the 
water  pressure  comes  up  to  a  pre-deter- 
mined  value,  it  allows  the  next  contactor 
to  operate  which  starts  up  the  filament 
motor  generator  units.     As  the  genera- 


tors reach  their  full  voltage,  relays  in  the 
filament  lines  make  contact,  the  next 
circuit  breaker  does  its  bit  and  the  60 
cycle  rectifier  for  the  grid  bias  and 
another  small  rectifier  for  the  plates 
of  the  fifty  watt  amplifier  tubes  add  their 
energy  to  the  circuit.  If  everything  to 
this  point  has  taken  place  to  the  satis- 
faction of  the  control  panel,  it  allows 
the  large  contactor  to  close  and  current 
is  furnished  to  the  bank  of  22,000  volt 
transformers  outside  the  station  room. 
Should  anything  be  amiss  while  this 
procedure  is  going  on,  the  contactor 
will  remove  the  offending  apparatus  from 
the  circuit  and  start  over  again. 

The  Big  Transformers 

'T'HE  four  10  kilowatt,  22,000  volt 
-*-  transformers  outside  the  station  are 
connected  with  the  two  transformers  in 
parallel  on  each  phase  and  the  output 
is  connected  to  four  water-cooled  kene- 
tron  rectifier  tubes,  which  give  full 
wave  rectification  on  two  phases  with  a 
resulting  pure  direct  current  at  voltages 
up  to  10,000.  The  out-put  of  the  rec- 
tifiers pass  through  a  bank  of  high  voltage 
choke  coils  and  condensers  which  smooth 
out  the  direct  current  until  it  is  free 
from  the  slightest  traces  of  ripple  or  hum. 
This  current  is  fed  to  the  four  water- 
cooled  modulator  tubes  and  to  two  water 
cooled  oscillators.  The  oscillators  work 
directly  into  a  "tank"  circuit  which 
(Turn  to  page  62) 


RADIO  AGE  for  October,  1925 


What  the  Broadcasters  ate  Doing 


31 


CI 


They  Never  Run 
Out  of  Ideas  in 
This  Radio  Qame 


The  FIRST 
CHILD 

Announcer 


Between  Announcing  and 

Acting  for  the  So- 

Called  Cinema 

This  Kid  is 

Very  Busy ! 


IT  SEEMS  as  if  there's  something 
new  under  the  sun  every  day  in  this 
interesting  radio  game.  The  latest 
thing — and  it  certainly  is  deserving  of 
mention — is  the  advent  of  a  young  movie 
star  into  the  ranks  of  dyed-in-the-wool, 
professional  announcers. 

Heretofore  most  of  the  country's  famed 
announcers  have  impressed  us  with  their 
maturity  and  staid  indifference;  viz., 
J.  Andrew  White,  Graham  MacNamee, 
and  others.  But  what  does  young  Dicky 
Brandon's  press  agent  do  but  put  some 
cute  knickers  on  his  youthful  form  and 
made  him  the  most  famous  of  all  an- 
nouncers— overnight! 

You  see,  it's  this  way.  Dicky  is  a 
movie  actor  by  trade.  He  lives  in 
Hollywood,  Los  Angeles  and  New  York 
at  specified  periods  of  the  year,  and 
though  he's  but  six  years  of  age,  he 
knows  his  stuff  and  is  looking  covetously 
at  the  Juvenile  Movie  Crown  now  held 
by  Jackie  Coogan,  the  original  Kid. 
And  it's  safe  to  say  that  Dicky  is  at 
least  second  to  Jackie. 

"First   in    Something" 

NOT  to  be  outdone  by  holding  a 
second  place,  however,  Dicky  de- 
cided to  be  first  in  something — and 
after  a  couple  of  visits  to  radio  studios 
on  the  Pacific  coast,  he  decided  his  forte 
lay  in  that  direction.  Dicky  is  par- 
ticularly adept  at  elocution,  singing,  and 


B?  MARY  JANE 
LAWRENCE 


\ 


You  may  not  believe  it,  but  "Dicky"  Brandon,  shown  above  in  a 
Witzel  photo,  is  a  coming  movie  star — second  only  to  the  famous 
Jackie — and  he  has  Jackie  beaten  in  that  he's  the  only  professional 
radio  announcer  among  the  kiddies — that  we  know  of,  anyiuay. 
We're  open  to  disputes,  however. 


plain  kiddibh  nonsense,  so  he  had  no 
trouble  in  getting  booked  for  programs 
with  the  best  of  them. 

That  was  four  months  ago,  and  today 
Dicky  spends  most  of  his  time  announcing 
via  radio  and  the  rest  of  his  time — really 
his  "spare-time,"  playing  juvenile  leads 
for  several  movie  companies  out  where 
the  oranges  grow,  and  where  it  never 
rains  except  on  unusual  days. 

How  did  it  come  about?  Well, 
dearie,  Dicky  just  horned  his  way  into 
the  announcing  game,  to  use  a  plebeian 
expression.  And  once  he  got  into  it, 
he.  found  it  well  nigh  impossible  to  get 
out.  He  had  a  habit  of  stopping  in  the 
middle  of  his  programs  when  he  was 
first  beginning,  and  carrying  on  an  infor- 
mal chat  with  his  potential  listeners. 

A  Modest  Youth 

OF  COURSE,  such  a  procedure  made 
a  "hit,"  and  although  Dicky  persist- 
ed that  he  was  just  doing  what  he'd 
heard  other  announcers  doing,  he  was 
told  his  extreme  youth  made  it  seem 
original,   even   if   he  claimed  it   wasn't. 

So  Dicky  was  won  to  radio  and  the 
"experienced"  announcers  gnashed  their 
teeth  and  took  a  back  seat. 

From  a  personality  standpoint,  Dicky's 
a  wow.  The  picture  shows  him  as  Little 
Fauntleroy,  but  that's  only  in  the  movies. 
He'll  probably  grow  up  to  be  a  he-man, 
if    he    decides    whether    to    be    a    movie 


star  or  a  radio  announcer.  Right  now 
he's  lying  awake  nights  wondering  just 
what  to  be.  You  see,  a  man  in  these 
days  has  gotta  work  hard  to  support 
his  father  and  mother.  And  at  the  age 
of  six  Dicky  Brandon  realizes  he's 
getting  old  and  must  look  to  the  future. 
Do  you  blame  him? 

He  tells  us  that  he  stays  awake  nights 
pondering  over  his  career.  But  we  have 
half  a  mind  to  believe  it's  the  income 
tax. 

He  Does  His  Stuff 

"DECENTLY  Dicky  demonstrated  he 
■*■  *■  could  do  anything  in  the  radio  line 
by  taking  over  the  entire  direction  of  a 
Los  Angeles  station  for  one  evening, 
when  he  was  announcer,  director,  pro- 
gram arranger,  office  boy,  and  what-not. 

Dicky  rounded  up  his  own  gang  of 
juvenile  entertainers  one  evening  at  7 
o  clock,  just  before  the  sun  went  down, 
and  from  7  to  8  o'clock  it  was  "Dicky's 
hour"  in  every  sense  of  the  word.  Kid 
songs,  monologues,  foolishness  and  child- 
ish laughter  rippled  out  on  the  radio 
waves — the  first  "stunt"  of  its  kind  ever 
produced. 

After  the  evening  s  entertainment 
Dicky  was  literally  snowed  under  with 
congratulatory  telegrams,  phone  calls 
and  special  messages — all  attesting  his 
inborn  ability  as  a  "radio  genius  extra- 
ordinary" at  the  tender  age  of  six  years! 
(Copyrighted:  1925  By  Radio  Age) 


32 


RADIO  AGE  for  October,  1925 


What  the  Broadcasters  are  Doing 


Radio  Interests  Qet  Together 

RADIO  COUNCIL  PLANNED 

Radio  Manufacturers'  Association 
Starts  Drive  to  Unite  all  Radiodom 
in  One  Common,  Constructive  Purpose 


THE  organization  of  a  National 
Radio  Council  to  include  represent- 
atives of  the  manufacturers,  job- 
bers, dealers,  broadcasting,  agricultural 
interests,  trade  papers,  listeners,  and 
others  interested  in  radio,  is  being  plan- 
ned by  the  Radio  Manufacturers'  Associ- 
ation as  the  result  of  a  report  made  by 
Frank  Reichmann,  chairman  of  its  com- 
mittee on  publicity  and  public  relations. 

Mr.  Reichmann  in  his  report  says: 

"All  listeners  organizations,  especially 
the  American  Radio  Association  and  the 
Broadcast  Listeners  Association  of  Amer- 
ica, should  be  invited  to  hold  their  next 
convention  at  the  same  time  and  place 
as  the  RMA. 

"Every  broadcasting  station  should  be 
invited  to  send  a  delegate  to  a  meeting  of 
broadcasters  to  be  held  at  the  same  time. 

"All  local  radio  trades  associations 
should  be  asked  to  send  delegates  to  a 
similar  meeting,  probably  under  the 
auspices  of  the  National  Radio  Trades 
Association. 

"The  publishers  of  all  radio  trade 
papers  should  also  meet  at  the  same  time 
and  organize  their  branch  of  the  industry. 

"I  especially  want  to  call  attention 
to  the  necessity  of  organizing  the  radio 
listeners  throughout  the  country.  The 
experience  of  the  National  Automobile 
Chamber  of  Commerce  is  one  by  which 
we  can  profit.  The  automobile  manufac- 
turers, as  a  body,  were  unable  to  compel 
the  construction  of  hard  roads,  or  carry 
on  legislative  reforms  which  are  vital  to 
the  industry.  By  supporting  the  Ameri- 
can Automobile  Association,  composed  of 
car  owners,  this  work  was  all  carried  out 
in  a  very  satisfactory  manner,  the  manu- 
facturers giving  their  support  to  the 
"Three  A's".  A  great  deal  of  similar 
work  can  be  carried  on  through  the  local 
radio  trade  associations,  which  have  been 
or  are  being,  organized,  in  practically 
every  city  in  the  country.  Also,  it  would 
be  to  the  advantage  of  the  entire  industry 
to  have  all  these  radio  trade  associations 
welded  into  some  national  body  which 
can  cooperate  with  the  manufacturers. 
The  same  applies  to  the  publications  and 
the  broadcasters. 

Harmful  Laws  Feared 

I  WISH  to  emphasize,  at  this  time,  the 
fact  that  this  Association  cannot  now, 
and  probably  never  will  be  in  a  position 
to,  watch  for  and  guard  against  the 
passage  of  hostile  and  harmful  legisla- 
tion in  the  assemblies  of  the  entire  forty- 
eight  states.     Such  legislation  is  certain 


to  be  proposed.  The  industry  can  pro- 
tect itself  only  by  organizing  the  listen- 
ers, the  dealers,  and  the  jobbers  in  every 
state,  and  leaving  the  matter  to  them. 
This  is  what  the  automotive  industry 
has  done. 

"In  connection  with  the  broadcasting 
situation,  this  committee  suggests  that 
members  of  the  Association  who  operate 
broadcasting  stations  immediately  be  re- 
quested to  organize  a  broadcasting  divis- 
ion of  this  Association. 

"Closer  affiliation  of  all  the  local  radio 
trades  association  would  also  make  it 
possible  to  carry  out  an  organized  cam- 
paign to  increase  the  sale  of  radio 
apparatus.  We  believe  that  the  manu- 
facturers' association  should  outline  such 
a  campaign  and  suggest  it  to  the  local 
association  for  the  latter's  use.  One 
thing  in  this  connection  would  be  a  group 
advertising  campaign  of  the  dealers,  in 
each  city,  using  advertisements  which 
would  call  attention  to  the  more  import- 
ant special  events  to  be  broadcast  by  the 
stations  in  the  immediate  locality. 
Closer  affiliation  between  the  broad- 
casters, trade  association  and  the  manu- 
facturers would  help  a  great  deal  to  carry 
through  campaigns  of  this  kind. 

"This  committee  recommends  the 
establishment  of  a  National  Radio  Coun- 
cil to  be  composed  of  representatives  of 
the  Radio  Manufacturers'  Association, 
the  dealers  and  jobbers,  manufacturers 
agents,  the  broadcasters,  the  radio  paper 
publications,   and  the  listeners. 

"We  are  advised  that  the  National 
Radio  Trades  Association,  which  has 
done  much  excellent  work  in  the  past,  is 
anxious  that  the  manufacturers  get 
behind  an  organization  of  the  dealers  and 
jobbers.  We  are  also  advised  that  the 
National  Association  of  Broadcasters  is 
willing  to  help  in  organizing  a  central 
council,  and  we  are  assured  that  we  will 
have  the  active  support  of  the  two  lead- 
ing listeners  organizations — the  American 
Radio  Association  and  the  Broadcast 
Listeners  Association  of  America. 

"We  are  also  of  the  opinion  that  the 
American  Radio  Relay  League  should 
be  invited  to  become  a  member  of  the 
council  and  we  can  assure  you  at  this 
time  that  the  Farm  Radio  Council  will 
become  an  active  member. 

"Inasmuch  as  all  radio  shows  are  pri- 
marily advertising  and  publicity  features, 
this  committee  believes  that  special 
attention  should  be  directed  by  all  show 
managements  to  obtaining  the  coopera- 
tion of  public  officials  in  making  the  radio 


shows  civic  events.  For  the  same  reason, 
we  believe  that  special  effort  should  be 
made  by  the  management  of  all  shows  to 
insure  the  attendance  of  school  children 
through  the  inducement  of  specially 
priced  tickets,  prizes  for  home  built 
radio  apparatus,  etc. 

"This  committee  also  recommends  that 
the  association  take  up  the  matter  of 
further  encouraging  the  teaching  of  radio 
in  all  manual  training  classes  in  all 
public  and  private  schools. 

"This  committee  believes  that  by  care- 
ful, conservative  action  during  the  com- 
ing year,  a  great  deal  can  be  done  to 
cement  together  all  those  interested  in 
radio,  to  the  end  that  the  industry  will 
be  better  prepared  to  repel  legislative 
and  other  attacks,  and  that  even 
greater  public  interest  in  radio  will  be 
assured." 

The  report  was  approved  at  the 
Atlantic  City  convention  of  the  RMA 
and  the  work  of  organizing  a  national 
council  is  already  under  way. 

The  following  officers  elected  at  the 
recent  RMA  convention  in  Atlantic 
City  will  meet  on  Tuesday  evening, 
September  15,  to  consider  plans  for  great- 
ly broadening  the  work  of  the  Associa- 
tion: 

President — Herbert  rf.  Frost. 

Secretary — Carl  D.  Boyd. 

Treasurer — S.   I.    Marks. 

Directors  At-Large — 

Powell  Crosley,  Jr.,  First  Vice  Presi- 
dent, Harry  L.  Bradley,  L.  G.  Baldwin, 
Edward  H.  Jewett,  E.  T.  Cunningham. 

Directors  Eastern  Division — 

Godfrey  Gort,  Second  Vice-President, 
H.  H.  Eby,  Alex.  Eisemann,  R.  E. 
Thompson,  James  L.  Schwank,  A.  U. 
Howard,  S.  B.  Trainer. 

Directors  Western  Division — 

E.  N.  Rauland,  Third  Vice-President, 
A.  J.  Carter,  Frank  Reichmann,  J.  M. 
Stone,  H.  H.  Frost,  W.  H.  Huth,  John  C. 
Tully,  L.  E.  Parker. 

IT  is  planned  that  the  eastern  and 
western  boards  and  members  meet  at 
regular  intervals  in  New  York  and 
Chicago  while  the  entire  board  will 
alternate  its  meetings  between  the  two 
cities.  Many  problems  of  tremendous 
importance  to  the  industry  are  now  in 
the  hands  of  the  committees  and  action 
is  expected  during  the  New  York  meet- 
ings. These  board  and  committee 
meetings  will  culminate  in  a  general 
membership  meeting  on  Thursday  even- 
ing,   September    17. 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour  33 


The  Latest  in  Radio  Construction 

Single  and  Dual  Controls 
for  5-Tube  Sets 


By  JOHN  B.  RATHBUN 


Copyright:  1925 


THERE  has  been  much  argument  of 
late  on  the  subject  of  simplifying 
the  wavelength  tuning  controls  on 
five-tube  radio-frequency  receivers,  re- 
ducing the  conventional  three  controls 
to  one  or  two  dials.  While  there  is 
much  to  be  said  in  favor  of  the  simpler 
control  system,  it  is  not  all  pure  gain, 
for  the  reduction  in  the  number  of  dials 
is  attended  with  certain  difficulties  often 
overlooked  by  the  adherents  of  the  single 
and  dual  control  that  will  be  evident  on 
a  short  study  of  the  proposition  by  an 
unbiased  investigator.  Mechanical  sim- 
plification is  often  attended  by  certain 
practical  psychological  problems  which 
in  turn  depend  upon  the  state  of  mind 
of  the  operator. 

Under  ordinary  conditions,  selectivity 
increases  with  the  number  of  tuning 
units  employed,  and  with  the  three  tuning 
controls  ordinarily  employed  on  five-tube 
radio  frequency  receivers  a  high  degree  of 
selectivity  can  be  attained  without  mak- 
ing any  one  of  the  controls  unduly  crit- 
ical. For  example,  with  three  controls, 
each  of  the  individual  units  can  be  quite 
broad  yet  collectively  the  combination 
results  in  excellent  selectivity  for  each 
of  the  units  corrects  and  augments  the 
effects  of  the  unit  going  before.  Under 
ordinary  conditions,  using  three  dials,  a 
station  may  come  in  with  fair  volume 
over  five  divisions  or  more  on  each  of  the 
dials  and  yet  the  set  as  a  whcle  will  be 
extremely  sharp.  If  one  dial  tends  to  be 
very  sharp  and  critical,  the  effects  can 
be  modified  by  making  adjustments  with 
the  remaining  dials. 

Now  let  us  assume  the  same  degree  of 
total  or  overall  selectivity  with  only  two 
dials  operating  the  former  three  tuning 
units  through  gearing  or  similar  mechani- 
cal connection.  As  the  total  movement 
must  be  had  with  two  dials   instead   of 


Timely  Set  Builders 
Will  Welcome  Novel 
Idea  to  Simplify  the 
Tuning  of  R.  F.  Sets 


three,  the  stations  will  no  longer  be 
tuned  in  over  so  wide  a  range  of  scale 
divisions,  and  instead  of  being  in  evi- 
dence over  five  dial  divisions  as  before, 
the  band  will  be  reduced  to  approximate- 
ly three  divisions.  Thus,  the  tuning  is 
more  critical  and  requires  closer  and 
more  careful  dial  adjustment  than  when 
the  three  dials  are  employed. 

There  are  fewer  dials  to  look  after, 
that  is  true,  but  on  the  other  hand  it  is 
more  difficult  to  separate  stations  lying 
close  together  in  regard  to  wavelength, 
and  the  effect  of  bunched  stations  on  the 
lower  wavelengths  is  more  difficult  to 
overcome.  Two  dial  control  absolutely 
demands  modern  variable  condensers  of 
the  straight-line-wavelength  or  straight- 
line-frequency  type  by  which  the  stations 
are  distributed  over  the  dials  with  greater 
uniformity  than  with  the  old  straight-line 
capacity  type  having  simple  semi-circular 
plates.  Two  dials  are  more  easily  moved 
together  or  "tracked"  than  three  dials, 
but  the  tracking  must  be  done  more 
accurately. 

With  a  single  dial  control  still  more 
accurate  adjustment  will  be  required  for 
a  given  selectivity,  for  instead  of  coming 
in  over  five  dial  divisions  as  with  the 
three  dials,  only  one-third  the  number  of 


divisions  will  now  be  available.  Here, 
the  necessity  for  uniform  station  distri- 
bution over  the  scale  applies  with  triple 
force,  and  with  approximately  six  sta- 
tions to  each  of  the  100  dial  divisions, 
extreme  care  in  adjustment  is  necessary. 
Each  wavelength  must  be  absolutely 
definite  within  less  than  one-sixth  of  a 
dial  division  if  we  expect  to  tune  in  each 
of  the  600  or  more  broadcasting  stations 
now  licensed  without  the  further  correc- 
tion of  a  second  or  third  dial. 

With  less  than  three  controls,  highly 
selective  tuning  units  are  necessary  to 
prevent  the  overlapping  of  signals  lying 
within  a  few  meters  of  each  other.  It  is 
absolutely  essential  that  the  inductances 
be  immune  to  external  fields  and  influen- 
ces and  that  they  act  only  on  the  im- 
pulses received  through  the  antenna' 
system.  Further,  there  should  be  some 
means  of  adjusting  the  sharpness  of  the 
tuning  within  the  set  so  that  it  can  be 
closely  adjusted  to  meet  local  conditions. 
It  should  be  fairly  broad  out  in  the 
country  where  there  is  little  interference 
and  should  be  capable  of  a  considerable 
sharpening  in  districts  where  there  are 
many  strong  local  stations. 

Now  comes  the  counter  argument  that 
it  is  easier  to  make  close  sharp  adjust- 
ments on  one  or  two  dials  than  it  is  to 
make  fairly  broad  adjustments  on  three 
dials.  Well,  perhaps  it  is  under  certain 
conditions,  but  to  my  mind  it  is  largely 
a  matter  of  personal  taste.  It  depends 
upon  whether  the  individual  prefers  to 
make  three  rather  broad  adjustments  or 
only  one  or  two  sharp  and  accurate  ad- 
justments. At  first  glance  it  would  seem 
that  the  single  dial  system  would  be  the 
ideal  proposition,  and  so  it  would  be  if 
there  were  only  50  to  100  stations  spread 
well  over  the  length  of  the  dial,  but  owing 
(Turn  to  page  36) 


Blueprints  Explaining  the  Single  and  Dual  Controls  on  pages  34,  35,  38  and  39 


FiG.f 

TYf/c/tL  /?/}D/o rReec/e/vcy  C/ftCU/T 0//}- 

6/?/W  SHOW//VG  TWO  STAGES  Or  /Z40/O  F/?E- 
pUB/VCY /WD  OETECTOfi?  TU0E. 


FIG  2 

OZ/?ECT  CO/VOEWS/EJ?  6&4/?//V<5  SYSTEM 
WITH  S/A/GLE  D/#L  COMT&Ol.  O/V  C2. 


F/6.3 

/ZE0UCT/0A/  GEM/PEP  CO/VOEA/SE^S  W/TH /? 
S/r/GCE  SeO  £>EG*?EE £>//f£.  COS/TttH-. 


cory/e/GtfT  /92G 

/B4D/0  <4GE,  /A/C. 
CH/C/fGOj/LL. 


J.B.&4TA/&C//Y 

/fat-zooo 


f/6.64 


F/e.6 

COUPLER  CO/L 


F/&.7 
TRANSFORMER  CO/L 


CORYR/G/ST  /^S 
R4D/OS?6E,WG. 
CWC/9GO,  /LL . 


36 


RADIO  AGE /or  October,  1925 


(Continued  from  page  33) 
to  the  present  congestion  this  is  far  from 
being  the  case.  Stations  bunched  at  the 
ends  of  the  dials,  and  varying  only  by 
ten  kilocycles  from  one  another,  makes 
single  dial  adjustments  rattier  difficult. 

Tuned  R.  F.  Circuits 

BEFORE  the  various  tuning  methods 
can  be  taken  up  in  detail,  it  will  be 
advisable  to  examine  the  circuit  diagram 
•  of  a  conventional  two  stage  radio  fre- 
quency circuit  so  that  the  conditions 
can  be  more  fully  understood.  In  Fig. 
1  is  shown  the  circuit  of  two  tuned  radio 
frequency  stages  and  detector,  the  radio 
tubes  being  at  (RF-1)  and  (RF-2)  while 
the  detector  tube  is  at  (DET).  All 
three  tubes  are  tuned  accurately  to 
wavelength  by  the  three  variable  con- 
densers (CI— C2— C3)  connected  across  the 
secondary  windings  of  the  air-core  radio 
f  requency  couplers  or  transformers  (LI -L2- 
L3),  and  as  shown  in  the  diagram,  these 
condenser  adjustments  may  be  individual 
or  else  they  can  all  be  adjusted  at  one 
time  by  means  of  certain  mechanism 
about  to  be  described. 

It  is  important  to  note  at  this  point 
that  the  (F)  ends  of  the  secondary  coils 
are  all  connected  to  a  common  wire,  the 
(—A)  line  and  ground  connection,  and 
that  all  the  rotors  of  the  variable  con- 
densers are  therefore  also  connected  to 
this  ground  (—A)  wire.  The  stators  of 
the  condensers  are  connected  individually 
to  the  grids  (G)  of  the  three  tubes.  This 
makes  "gang  condenser"  construction 
possible.  A  single  rotor  element  can  be 
used  for  all  three  stages  meshing  with 
three  independent  stator  units,  and  all 
units  can  be  used  with  one  tuning  dial 
attached  to  the  rotor  shaft. 

One  method  of  single  dial  tuning  is  to 
couple  the  rotors  of  the  three  variable 
condensers  (C 1— C2— C3)  together  mechan- 
ically by  means  of  gear  wheels  at  (Gl— 
G2— G3)  shown  in  Fig.  2.  The  electrical 
connections  are  made  exactly  as  in  Fig. 
1,  and  one  movement  of  the  dial  (D) 
mounted  on  the  center  shaft  of  condenser 
(C2)  tunes  all  three  stages  simultaneously. 
While  this  does  not  simplify  the  tuning 
units  to  any  extent,  yet  it  does  reduce 
the  dial  control  to  one  operation  and  for 
this  reason  the  arrangement  has  proved 
quite  popular. 

At  (VI)  and  (V2)  are  two  variable 
condensers  of  very  small  capacity  used 
for  balancing  the  condensers  (CI)  and 
(C3)  so  that  all  of  the  main  condensers 
are  of  exactly  the  same  capacity  and  so 
that  they  will  all  accurately  "track"  with 
one  another  at  any  given  dial  position. 
When  once  adjusted,  the  balancing  or 
compensating  condensers  (VI)  and  (V2) 
need  no  further  attention.  This,  or  an 
equivalent  method,  must  be  used  as  the 
commercial  variable  condensers  never 
have  exactly  the  same  characteristics 
when  purchased  on  the  open  market,  and 
it  is  imperative  that  they  act  in  exact 
unison  on  the  turning  of  the  dial. 

The  gears  (Gl— G2— G3)  are  made  of 
fiber  or  other  non-conducting  material, 
and  are  provided  with  a  means  of  fas- 
tening them  tightly  to  their  respective 
condenser  shafts  without  danger  of  slip- 
ping. The  diameters  depend  upon  the 
center-to-center  distance  between  con- 
densers, but  in  all  cases  the  diameters 
and  numbers  of  teeth  must  be  the  same 
on  all  gears.  If  there  is  a  variation  in 
the  diameter  or  number  of  teeth,  then 
the  shafts  will  turn  through  different 
angles  when  the  knob  is  turned  and  the 
set  cannot  be  tuned  in. 

An  improvement  on  the  first  gear 
arrangement  is  shown  in  Fig.  3  where  the 


gears  (Gl— G2— G3)are  fastened  on  the  con- 
denser shafts  as.  before,  but  are  connected 
together  by  small  intermediate  pinions 
(PI)  and  (P2).  In  the  first  place,  the 
diameter  of  the  gears  is  considerably 
reduced  by  this  method,  thus  making  it 
a  simpler  matter  to  mount  the  apparatus 
on  the  panel.  Secondly,  by  making  the 
diameter  of  pinion  (PI)  exactly  half  the 
diameter  of  the  gears  (Gl— G2-G3),  the 
dial  (D)  mounted  on  the  shaft  of  (PI) 
will  turn  through  360°  instead  of  through 
180°  and  this  will  doubly  spread  out  the 
stations  and  facilitate  tuning. 

It  is  evident  that  a  full  360°  turn  will 
reduce  the  number  of  stations  per  dial 
division  and  thus  will  eliminate  over- 
lapping and  will  make  the  set  correspond- 
ingly more  selective  and  less  critical. 
In  effect  it  is  really  a  vernier  system  with 
an  increased  active  arc  of  dial,  thus  at 
least  partly  offsetting  one  of  the  bad 
features  of  single  dial  control.  The  small 
compensating  adjustable  condensers  are 
at  (VI)  and  (V2)  as  before,  for  balancing 
up  unequalities  in  the  main  tuning  ele- 
ments. In  case  where  a  180°  dial  is 
desired,   it   can    be    mounted   on   one   of 


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the  condenser  shafts  as  before  so  that 
it  will  turn  at  the  same  rate  as  the  conden- 
ser plates. 

Gang  Condenser  Control 

GANG  condensers  consist  of  a  single 
assembly  made  up  of  two  or  more 
electrically  independent  stators  and  a 
single  rctor  which  meshes  simultaneously 
with  all  of  the  stators  with  a  single  dial 
movement.  The  principle  on  which  this 
system  works  was  suggested  in  the  para- 
graph dealing  with  the  circuit  diagram  of 
Fig.  1  where  it  was  stated  that  the  rotors 
of  all  variable  condensers  are  connected 
to  the  common  (—A)  line.  The  use  of  a 
single  rotor  greatly  simplifies  the  con- 
struction, and  in  many  cases  takes  up 
less  space — at  least  panel  space. 

A  "two-gang"  condenser  is  shown  by 
Fig.  4  where  the  two  independent  stator 
units  (ST— 1,  ST— 2)  are  carried  by  the 
frame  (e—  f),  and  where  a  single  rotor  on 
the  shaft  (R)  meshes  with  both  stator 
sections.  The  stators,  are  of  course, 
insulated  from  one  another  and  from  the 
rotor.  The  rotor  connection  (—A)  goes 
to  the  (—A)  line  and  ground  while  the 
stator  sections  connect  with  the  grids  of 
two  tubes  at  (Gl)  and  (G2).  If  three 
tubes  are  to  be  controlled,  then  a  second 


The  Magazine  of  the  Hour 

simple  condenser  is  installed  for  the  third 
tube;  making  two  controls  necessary. 
The  panel  space  required  is  only  that  of 
a  single  condenser,  but  the  assembly  of 
course  extends  farther  back  into  the 
cabinet  than  with  a  single  condenser. 

Fig.  S  shows  a  "three-gang"  condenser 
with  three  independent  stators  (ST-1, 
ST— 2,  ST— 3)  and  a  single  rotor  (R). 
With  this  assembly  it  is  possible  to  tune 
all  three  stages  of  the  circuit  of  Fig.  1 
by  a  single  tuning  dial  mounted  on  the 
end  of  the  rotor  shaft.  A  condenser  of 
this  sort  takes  a  panel  space  equal  to 
that  of  a  single  condenser,  but  it  is  so 
long  that  it  generally  extends  the  full 
depth  of  the  cabinet.  However,  this  is 
not  a  serious  objection  as  the  tube  sockets 
can  be  rearranged  without  trouble. 

It  will  be  noted  that  small  compensat- 
ing condensers  (VI)  and  (V2)  are  con- 
nected _  between  the  rotor  and  stator 
plates  in  both  cases  for  balancing  the 
capacity  of  the  stators  as  previously  ex- 
plained. One  such  compensator  is  used 
for  the  two  gang  condenser  and  two  com- 
pensators (VI)  and  (V2)  are  employed 
on  the  three  gang  type.  Usually,  the 
compensating  condensers  consist  of  a  pair 
of  small  adjustable  leaves  mounted 
directly  on  the  condenser  and  built  into 
it  so  that  separate  condensers  are  not 
needed  for  the  purpose.  As  they  need 
adjustment  only  once  after  the  set  is 
built,  there  is  no  necessity  of  mounting 
dials  for  the  compensators  on  the  front 
panel. 

Self-Contained  Field  Coils 

ANY  air-core  radio  frequency  coupler 
and  transformer  can  be  used  in  con- 
nection with  the  gang  and  geared  con- 
densers. It  is  possible  to  pack  such 
coils  into  a  very  small  space  without 
back-feeding  between  stages. 

A  single  circuit  coupler  is  shown  by 
Fig.  6.  It  consists  of  a  single  continuous 
winding  which  terminates  at  the  posts 
(G)  and  (F)  and  is  tapped  at  the  points 
(tl)  and  (t2)  for  the  connection  of  the 
antenna.  The  schematic  diagram  of  the 
equivalent  solenoid  coil  is  shown  by 
Fig.  6A  which  is  lettered  to  correspond 
to  the  coupler  drawing.  This  single  cir^ 
cuit  coupler  is  used  for  the  antenna  coup- 
ler as  installed  at  (LI)  in  Fig.  1,  and  the 
two  taps  (Al)  and  (A2)  provide  for 
different  degrees  of  sharpness  or  broad- 
ness in  the  tuning. 

Approximately  200  turns  of  No.  24  D.S. 
C.  wire,  lj-^"in  diameter  is  used  for  mak- 
ing the  coil.  Tap  (tl)  for  terminal  (Al)  is 
taken  at  the  sixteenth  turn,  while  tap 
(t2)  for  terminal  (A2)  is  taken  at  the 
sixtieth  turn.  Some  little  experimenting 
will  be  required  to  balance  up  the  coil 
properly  in  order  to  cover  the  band  of 
broadcasting  wavelengths  ranging  from 
200  to  550  meters  when  used  in  connec- 
tion with  a  0.00035  mf.  variable  con- 
denser, and  for  this  reason  it  is  better  to 
purchase  the  coils  than  to  attempt 
their  manufacture  at  home.  When  a 
solenoid  is  bent  into  a  toroidal  form,  it 
does  not  follow  the  same  laws  as  it  did 
when  used  as  a  straight  solenoid. 

Antenna  connection  (Al)  gives  ex- 
treme sharp  tuning,  for  the  coupler  then 
acts  like  an  auto-transformer  with  a  high 
ratio  between  the  virtual  secondary  and 
primary  coils.  Connecting  the  antenna 
to  (A2)  greatly  broadens  the  tuning  for 
use  where  there  is  not  much  local  inter- 
ference. In  this  way  we  can  control  the 
tuning  values  to  suit  local  conditions. 

A  two  circuit  coil,  consisting  of  an 
independent  primary  and  secondary,  is 
outlined  in  Fig.  7.     This  coil  is  used  as  a 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


37 


radio  frequency  transformer  as  at  (L2) 
and  (L3)  in  Fig.  1  and  its  secondary  coil 
is  tuned  by  a  0.00035  mf.  condenser  as 
before.  Roughly,  the  secondary  consists 
of  160  turns  of  wire  in  the  secondary  and 
40  turns  in  the  primary,  but  this  is  sub- 
ject to  slight  variations  in  the  method  of 
winding.  As  with  the  coupler  coil,  this 
is  quite  a  trick  to  make  at  home,  and  it 
will  be  found  much  surer  and  will  cost 
no  more  in  the  long  run  to  purchase  the 
coils  ready  made.  This  will  eliminate 
much  of  the  guesswork  and  the  amateur 
deals  with  enough  unknown  quantities 
as  it  is.  There  are  at  least  three  stan- 
dard makes  of  these  coils  now  on  the 
market  and  they  can  be  obtained  without 
difficulty  from  reliable  dealers.  A  sche- 
matic diagram  of  the  coil  in  solenoid 
form,  is  given  by  Fig.  7A  which  is  lettered 
to  correspond  with  Fig.  7. 

Both  the  coupler  and  transformer  are 
provided  with  a  metal  bracket  (b)  which 
at  one  time  supports  the  coil  from  the 
condenser  and  makes  a  connection 
between  the  (G)  end  of  the  secondary- 
coil  and  the  stator  plates  of  a  low-loss 
condenser. 

When  used  as  a  transformer,  the  plate 
of  the  preceeding  tube  is  connected  to 
the  coil  post  (P),  the  coil  post  (G)  con- 
nects with  the  grid  of  the  following  tube, 
the  post  (B)  connects  to  the  positive 
"B"  (+B)  45  volt  battery  line,  and  post 
(F)  connects  with  (—A)  and  ground. 

Completely  Assembled  Set 

THE  completely  assembled  five-tube 
radio  frequency  set  is  a  very  corn- 
arrangement  adapted  to  a  7"  x  18" 
panel,  and  an  examination  "will  show 
that  hardly  a  cubic  inch  of  space  is  wasted, 
yet  the  parts  are  easily  accessible  for 
wiring  and  for  adjustment.  In  spite  of 
the  close  packing  of  the  parts  into  the 
limited  space  there  is  no  trouble  with 
feed-backs  or  other  interchanges  of  en- 
ergy between  the  inductances. 

A  conventional  straight  radio  frequency 
circuit  is  employed  in  the  receiver  shown, 
the  excellent  results  obtained  being  deter- 
mined by  the  materials  rather  than  upon 
any  trick  in  the  circuit  itself,  but  of  course 
any  other  circuit  can  be  used  that  calls 
for  the  same  equipment  given  in  these 
specifications.  There  are  two  radio 
frequency  stages,  detector,  and  two  audio 
frequency  stages  which  give  a  high  de- 
gree of  selectivity  and  good  distance  on 
the  loud  speaker.  When  desired,  the 
reflex  principle  can  be  employed  with  the 
equivalent  of  four  stages  of  radio  fre- 
quency and  two  stages  of  ausio  ampli- 
fication, but  in  view  of  the  performance 
with  the  radio  frequency  circuit  this  is 
not  necessary  nor  even  desirable. 

One  single  variable  condenser  (0.00035 
mf.)  is  used  to  tune  the  antenna  coupler, 
while  a  two-gang  condenser  shown  at  the 
left  tunes  both  radio  frequency  trans- 
former by  a  connection  across  the  coil 
secondaries  as  indicated  in  Fig.  1.  By 
this  means  we  have  only  two  wave- 
length tuning  controls  for  the  five  tubes, 
a  control  system  that  is  simple  to  under- 
stand and  handle  and  yet  is  not  excessive- 
ly sharp  nor  critical.  A  single  dial  con- 
trol with  a  three-gang  condenser  is  so 
long  that  it  interferes  seriously  with  the 
layout  scheme  determined  upon  for  the 
sockets,  and  is  not  so  easy  to  handle  as 
the  circuit  arrangement  finally  adopted. 

All  five  tube  sockets  are  mounted  in  a 
row  on  a  strip  of  bakelike  that  serves  as 
a  sub-panel  and  the  sub-panel  in  turn  is 
connected  by  metal  end  brackets  to  the 
front  panel  so  that  no  wood  sub-base  is 
necessary.  However,  it  is  not  absolutely 
necessary  to  follow  this  exact  construc- 


tion and  the  standard  form  of  wood 
bottom  board  can  be  used  if  desired.  In 
the  photograph,  the  audio  transformers 
are  placed  out  of  the  way  beneath  the 
sub-base  where  they  also  act  as  supports 
for  the  thin  strip  of  bakelite,  and  holes 
drilled  in  the  sub-panel  allow  the  trans- 
former binding  posts  to  pass  through  for 
support  and  electrical  connection. 

Special  attention  is  called  to  the  gang- 
condenser  at  the  left  and  its  connection 
to  the  two  transformers.  The  transfor- 
mers are  connected  to  the  gang-condenser 
and  supported  by  it  through  thin  metal 
strips  bent  up  to  form  brackets  as  well 
as  electrical  conductors.  These  three 
parts  are  then  assembled  in  one  unit 
before  the  condenser  is  attached  to  the 
front  panel,  making  the  wiring  a  very 
simple  matter  as  all  of  the  wiring  connec- 
tions are  then  few  and  in  the  open. 

Circuit  Diagram 

A  pictorial  wiring  diagram  of  the  re- 
ceiver is  shown  by  Fig.  9.  This  circuit 
is  a  simple,  five-tube  radio-frequency  lay- 
out without  an  attempt  at  regeneration, 
reflexing  or  other  diversion  from  standard 


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practice,  the  high  efficiency  of  the  coils 
making  it  unnecessary  to  use  other  than 
a  standard  circuit.  A  potentiometer 
(PO)  used  for  controlling  the  grid 
potential  of  the  first  radio  frequency- 
tube  is  the  only  control  outside  of  the 
wavelength  controls  affected  by  the 
three  variable  condensers,  and  the 
potentiometer  is  used  to  clarify  reception 
and  to  vary  the  volume  rather  than  to 
control  free  oscillations. 

To  simplify  the  filament  controls,  a 
somewhat  novel  arrangement  of  the 
control  resistances  has  been  adopted. 
Only  one  rheostat  (Rl)  is  installed  and 
that  rheostat  controls  the  radio-frequency 
tube  current.  The  filament  current  for 
the  detector  tube  (DET)  and  the  two 
audio  frequency  amplifving  tubes  marked 
(AUD-1)  and  (AUD-:2)  are  controlled 
automatically  by  three  (R2—  R3—  R4) 
Amperites  and  therefore  need  no  atten- 
tion while  tuning-in.  It  has  been  found 
by  experiment  that  the  detector  tube  is 
not  in  the  least  critical  to  rheostatic 
control  in  this  circuit  and  therefor  can 
be  controlled  by  a  fixed  resistance  (R2)  as 
well  as  by  the  detector  rheostat  com- 
monly used  in  other  circuits.  The  bat- 
tery cutout  switch  (SW)  opens  and  closes 


the  "A"  battery  circuit  and  must  be 
installed  as  there  is  no  other  method 
available  for  shutting  down  the  detector 
and  two  audio  tubes. 

Looking  at  the  coils,  it  will  be  seen  that 
the  antenna  coupler  (LI)  is  of  che  single 
circuit  type  illustrated  by  Fig.  6  and 
carries  the  two  corresponding  antenna 
taps  (Al)  and  (A2)  for  sharp  and  broad 
tuning  respectively.  The  posts  are  con- 
nected to  the  terminals  (ANT— 1)  and 
(ANT— 2)  on  the  left  end  of  the  sub-panel 
where  the  proper  antenna  connection 
can  be  found  by  experiment. 

Dotted  lines  (a— b)  drawn  to  all  of  the 
coils  represent  the  metal  bracket  connec- 
tion made  from  the  (G)  post  to  the  stator 
of  the  variable  condensers,  these  brackets 
at  once  affording  a  connection  and  sup- 
port for  the  coils.  The  connection  from 
the  (— F)  post  on  the  coils  to  the  grounded 
condenser  rotor  is  made  by  a  strand  of 
rubber  covered  flexible  wire  in  all  cases. 
This  completes  the  connections  made  to 
the  0.00035  mf.  variable  condensers,  and 
it  should  be  noted  that  the  stator  posts 
are  marked  (s)  and  the  rotor  posts  of  the 
condensers  are  marked  (r)  to  prevent 
confusion  when  other  makes  of  conden- 
sers are  installed.  There  is  a  different 
in  the  method  of  bringing  out  the  con- 
denser connection  posts  in  different  makes 
of  condensers  and  this  is  likely  to  lead  to 
confusion  if  not  watched  carefully. 

A  0.00025  mf.  grid  condenser  (GC)  and 
a  2  megohm  leak  (GL)  will  be  found  most 
suitable  for  the  detector  tube.  The  fixed 
condensers  used  as  radio  frequency  by- 
passes, and  marked  (Kl,  K2,  K3,  etc.) 
are  clearly  marked  with  their  capacities 
and  call  for  no  comment  except  for  the 
0.005  mf.  fixed  condenser  (Kl)  used  as 
a  bypass  for  the  potentiometer.  It  should 
be  noted  that  (Kl)  is  connected  at  one 
end  to  the  center  post  of  the  potenti- 
ometer (PO),  and  at  the  other  end  to  the 
(—A)  line,  when  a  wire  wound  potenti- 
ometer is  used.  With  the  carbon  pilet  ype, 
or  pencil  mark  type  of  potentiometer  this 
bypass  condenser  can  be  eliminated  as 
such  potentiometers  have  little  or  no 
inductance  and  therefore  do  not  affect 
the  tuning  when  the  potentiometer  knob 
is  turned. 

For  the  clearest  and  most  satisfactory 
reception,  the  audio  frequency  transfor- 
mers (AFT-1)  and  (AFT-2)  should  have 
a  ratio  of  3.5-to-l  or  4-to-l.  Higher 
ratios  may  give  a  somewhat  greater 
amplification  and  volume  but  they  may 
also  cause  noise  and  distortion. 

Wiring  Notes 

Wiring  will  be  much  simplified  by  the 
use  of  small  rubber  covered  flexible  wire 
instead  of  the  more  usual  square  bus- 
wire.  Not  so  much  care  is  necessary  in 
arranging  the  runs  of  the  wire  to  avoid 
short  circuits,  the  difficulties  of  soldering 
in  close  corners  is  done  away  with,  and 
the  apparatus  can  be  arranged  to  a  better 
advantage  if  it  is  not  limited  by  considera- 
tions of  wiring.  The  distance  between  the 
binding  posts  is  measured,  allowing  a 
little  slack  in  the  rubber  cover  flexible 
wire,  and  then  after  cutting  to  length,  the 
ends  are  skinned  and  connection  lugs  or 
eyelets  are  soldered  to  the  ends  of  the 
wire.  As  this  soldering  can  be  done  on 
the  bench  or  table,  and  afterwards  con- 
nected in  place,  it  is  an  exceeding  con- 
venient method. 

Assembly  Drawing 

Fig.  10  is  a  plan  view  of  the  assembled 
parts  drawn  to  scale.     It  will  be  of  serv- 
ice in   laying  oat  the  work  although  the 
exact  dimensions  may  vary  from  those 
(Turn  to  page  40) 


40 


RADIO  AGE  for  October,  1925 


(Continued  from  page  37) 
shown  on  the  drawing  owing  to  the 
differences  in  the  various  makes  of  ap- 
paratus. The  circuit  shown  is  assembled 
on  a  7"  x  18"  standard  panel  and  re- 
quires a  cabinet  at  least  8J2  inches  in 
depth.  To  avoid  confusion,  no  wiring  is 
shown  on  this  layout — simply  the  appa- 
ratus, panels  and  supports. 

At  points  where  metal  brackets  are 
used  for  the  support  and  connection  of 
the  coils,  these  brackets  are  marked  (b) 
so  that  they  can  be  distinguished  from 
the  apparatus.  The  brackets  can  be 
made  easily  from  No.  24  to  No.  26  gauge 
sheet  brass,  the  strips  being  from  ^i 
inch  to  Yi  inch  wide  according  to  the 
apparatus  used.  In  any  case,  the  brack- 
ets must  be  heavy  and  stiff  enough  to 
afford  a  firm  support  that  will  not 
vibrate  when  the  set  is  being  handled. 
Compensating  Condensers 

The  purpose  of  the  very  small  com- 
pensating condensers  used  for  balanc- 
ing the  stators  of  the  gang-condensers 
has  already  been  described,  and  one 
of  the  condensers  is  shown  at  (VI)  in 
Figs.  9,  10.  Usually  a  small  neutralizing 
condenser  is  sufficient  for  this  purpose  or 
one  of  the  "Midget"  variable  condensers 
having  a  maximum  capacity  of  about 
0.000045  mf.  If  either  of  these  conden- 
sers is  not  available,  then  a  home  made 
condenser  can  be  made  by  using  two 
strips  of  brass  with  a  sheet  of  mica 
between  them. 

This  homemade  condenser  is  of  the 
"book"  type  as  illustrated  by  Fig.  10-A. 
The  brass  strips  (p-q)  are  approximately 
%  inch  wide  and  1  Yi  inch  long,  and  are 
fastened  firmly  to  the  sub-panel  at  one 
end  with  the  strip  of  mica  between  them. 
The  upper  brass  strip  (p)  overhangs  the 
rest  of  the  assembly  so  as  to  carry  the 
adjusting  screw  (m)  by  which  the  capa- 
city can  be  adjusted.  The  upper  strip 
(p)  is  given  a  curvature  before  assembly 
so  that  it  normally  tends  to  stand  away 
from  the  other  strip  (p).  By  turning 
down  the  adjusting  screw  (m),  the  capa- 
city can  be  increased  gradually  until  the 
two  stator  units  are  of  equal  capacity. 

Radio   Advances   Cause   of  a 
Universal  Language 

NEW  YORK. — Educators  should  be 
vitally  concerned — and  probably  are 
giving  the  matter  intensive  study — in  the 
announcements  of  super-power  broad- 
casting stations  that  are  in  contempla- 
tion and  some  actually  under  way  at  the 
50  kilowatt  rating,  in  the  opinion  of 
U.  J.  Herrmann,  managing  director  of 
the  Radio  World's  Fair.  An  Internation- 
al language  is  likely  to  become  a  neces- 
sity within  a  very  few  years,  Mr.  Herr- 
mann believes,  when  transoceanic  trans- 
mission of  musical  and  oratorical  pro- 
grams will  be  regular  features  to  delight 
people  of  many  nations. 

"A  determination  of  what  this  inter- 
national language  will  be  must  now  be 
arrived  at,"  contends  Mr.  Herrmann. 
"Realizing  this,  advocates  of  ILO  and 
Esperanto  are  debating  the  question 
more  emphatically  than  ever.  Of  course, 
English  now  encircles  the  globe,  as  the 
language  of  trade  and  increasing  use  in 
diplomacy,  and  there  are  strong  reasons 
why  it  should  be  adopted  as  the  universal 
tongue." 

This  universal  language  situation  will 
be  discussed  in  the  forum  that  will  be  a 
feature  of  the  Radio  World's  Fair,  during 
the  week  of  September  14th-19th,  when 
leading  educators  will  be  guests  of  the 
management,  along  with  students  from  a 
hundred  schools  and  colleges. 


Oav  *rwin,  pioneer  In  radio  industrial 
promotion,  advertising  and  general  pub- 
licity, has  been  appointed  associate  direc- 
tor of  the  Radio  World's  Fair,  succeed- 
ing the  late  James  F.  Kerr,  who  died 
last  June.  Announcement  of  this  import- 
ant news  to  the  radio  trade  and  to 
broadcast  listeners  was  made  this  week 
by  U.  J.  Herrmann,  managing  director, 
who  has  just  returned  from  the  Far 
North  and  the  MacMillan  Expedition 
to  expedite  the  elaborate  preparations 
that  are  being  made  to  make  the  Second 
Radio  World's  Fair  a  record  breaker  in 
the  number  of  exhibits  and  in  attend- 
and  as  well  as  for  special  features  of 
public  interest. 

The  First  Radio  World's  Fair  was  so 
large  that  it  required  Madison  Square 
Garden  and  the  Sixty-ninth  Regiment 
Armorv  to  house  it ;  the  second,  scheduled 
for  September  14th  to  19th,  1925,  will 
require  the  facilities  of  the  largest  hall 
in  the  world,  the  258th  Field  Artillery 
Armory,  five  times  as  large  as  Madison 
Square  Garden.  In  itself,  this  is  a  signi- 
ficant manifestation  of  the  tremendous 
development  of  radio. 

Mr.  Irwin  has  been  a  familiar  figure  at 
radio  expositions  throughout  the  country 
and  is  known  to  the  leaders  of  the  indus- 
try, not  only  from  a  merchandising  stand- 
point but  as  a  writer.  He  has  been  an 
enthusiastic  ".fan"  since  radio  broad- 
casting started. 

Mr.  Irwin  started  the  radio  section  of 
the  Brooklyn  Eagle  in  April,  1924, 
became  manager  of  the  entire  radio 
department  in  September,  1924,  and 
started  broadcasting  through  a  special 
studio  in  the  Eagle  Building  shortly 
thereafter  in  connection  with  Station 
WAHG.  These  programs  became  well 
known  throughout  the  United  States 
and  Canada.  He  resigned  to  become 
special  representative  of  the  Conde 
Nast  Publishing  Company  in  the 
establishment  of  a  radio  department  in 
the  advertising  end  of  their  business. 
In  such  capacity  he  participated  in  many 
merchandising  conferences  to  upbuild 
the  new  giant  industry  of  radio. 


Broadcasting  to  MacMillan 
from  Chicago 

Every  Wednesday  at  midnight  an 
unusual  radio  program  has  been  broad- 
cast from  Station  WGN  on  the  Drake 
Hotel,  Chicago,  to  the  MacMillan  Arctic 
Expedition.  The  programs  began  on 
the  day  that  Lt.  Comm.  MacMillan 
sailed  from  Boston,  June  17,  Bunker  Hill 
Day,  and  will  be  continued  until  the 
return  of  his  Arctic  Exploring  Expedi- 
tion late  in  September.  Commander 
MacMillan  made  special  request  before 
sailing  for  the  Arctic  that  his  old  friend 
and  college  fraternity  brother,  the  Rever- 
end Gardner  MacWhorter  of  Chicago, 
should  again  render  the  service  of  week- 
ly communication  from  home  that  he 
gave  during  the  MacMillan  Expedition 
of  1923-24  from  the  Zenith-Edgewater 
Beach  station   WJAZ. 

The  new  Zenith  broadcasting  station 
WJAZ  located  at  Mount  Prospect,  Illi- 
nois, some  twenty  odd  miles  out  of 
Chicago,  with  the  handsome  Spanish 
renaissance  studio  on  the  twenty-third 
floor  of  the  new  Straus  Building,  at 
Michigan  and  Jackson  Boulevards, 
Chicago,  was  not  completed  in  time  to 
carry  on  this  unique  broadcasting  feature, 
and  WGN  was  placed  at  the  disposal  of 
the  Reverend  Gardner  MacWhorter 
during  June  and  July  in  order  that  the 
weekly  midnight  programs  might  be 
given.     At  an  early  date  the  new  station 


The  Magazine  of  the  Hour 

WJAZ  will  be  opened  and  then  the 
famdiar  call:  "This  is  9  XN  calling 
WNP"  will  again  be  heard  until  the  re- 
turn of  the  MacMillan  Expedition. 
(9  XN  is  the  experimental  call  letters  of 
WJAZ  Station  and  WNP  is  Wireless 
North  Pole,  the  Zenith  station  on  board 
Commander  MacMillan's  private  Arctic 
schooner  "Bowdoin"  now  on  her  third 
expedition  into  the  Arctic.) 

The  MacMillan  programs  are  sent  at 
midnight  central  standard  time  and  are 
usually  of  an  hour  or  an  hour  and  a  half 
duration,  consisting  of  several  numbers  of 
music  given  by  friends  who  have  volun- 
teered for  this  personal  service  to  Com- 
mander MacMillan,  then  a  short  address 
by  some  close  friend  of  Commander 
MacMillan  who  has  usually  come  from 
a  distance  to  speak  to  the  Commander, 
and  the  rest  of  the  time  is  given  over  to 
the  reading  by  the  Reverend  Gardner 
MacWhorter  of  personal  messages  from 
relatives  of  the  men  in  the  Arctic  expedi- 
tion's personnel,  a  comprehensive  news 
digest  of  the  world's  events  of  greatest 
interest  to  the  explorers,  and  an  occasion- 
al humorous  incident  that  may  provoke  a 
little  laughter  in  the  cabin  of  the  "Bow- 
doin" or  the  S.  S.  "Peary,"  the  sister  ship 
of  the  "Bowdoin,"  under  command  of 
Lieut.  Comm.  Eugene  F.  McDonald,  Jr. 
_  During  the  past  two  months  many  dis- 
tinguished guests  have  taken  part  in  the 
MacMillan  programs  from  Chicago,  in- 
cluding: Dean  Paul  Nixon  of  Bowdoin 
College,  Maine,  Commander  MacMil- 
lan's Alma  Mater;  U.  J.  Herrmann,  pro- 
prietor of  the  Cort  Theatre,  Chicago, 
manager  of  the  New  York  and  Chicago 
"Radio  World's  Fairs;"  Mr.  and  Mrs. 
Frederick  H.  Rawson  of  Chicago,  parents 
of  Kenneth  Rawson,  fourteen  year  old 
Cabin-boy  of  the  "Bowdoin";  Mr.  and 
Mrs.  Elliott  Jenkins,  (Mrs.  Jenkins 
being  the  former  Alexandra  Carlisle 
who  placed  Calvin  Coolidge  in  nomina- 
tion for  the  Presidency  of  the  United 
States  at  the  Republican  National  Con- 
vention in  Chicago  in  1920);  S.  I.  Marks, 
treasurer  of  the  Zenith  Radio  Corpora- 
tion; H.  H.  Roemer  also  of  the  Zenith 
Radio  Corporation;  Jack  Gregson,  presi- 
dent of  the  Chicago  Bowdoin  College 
alumni;  F.  W.  Thurnau,  J.  W.  Cook,  and 
H.  F.  Juckett,  officers  of  the  Theta 
Delta  Chi  fraternity,  of  which  Comm. 
MacMillan  is  a  member. 

The  Wise.  Old  Man 

(Continued,  from  page  20) 
He  jumped  to  his  feet  and  rubbed  his 
hand  across  his  eyes.  His  pipe  was  on  the 
floor  andthe  rain  waspouringintheopen 
window  and  the  lightning  was  flashing. 
He  looked  towards  his  friend  but  he  had 
disappeared  as  mysteriously  as  he  had 
appeared  and  gazing  at  the  clock  on 
the  table  it  told  Billie  that  it  was  four 
o'clock  in  the  morning.  He  had  been 
asleep  four  hours  and  the  thunderstorm 
was  now  a  reality. 


John  B.  Rathbun 

and  His 

Famous 

RADIO  AGE 

BLUEPRINT  SECTION 

Can  Be  Found 

in  this  Magazine 

Every  Month 


RADIO.AGE/or  October,  1925 


The  Magazine  of  the  Hour        41 


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42 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


Hoover  Will   Call   Conference 
This  Fall 

Secretary  of  Commerce  Hoover  will 
call  a  national  radio  conference  here 
this  fall,  he  announced  on  his  return  to 
Washington  last  month.  Although  he 
has  not  had  time  to  set  a  date  or  draw 
up  a  program,  he  feels  that  a  conference 
is  necessary  once  a  year  and  believes 
the  three  already  held  have  benefited 
the  department  in  its  work.  They  have 
also  demonstrated  the  willingness  of  the 
fans,  manufacturers,  broadcasters,  ama- 
teurs and  other  interests  to  cooperate 
in  keeping  the  air  as  clear  and  clean  as 
possible. 

The  conference  will  be  called  in  October 
or  November,  it  is  now  believed,  partly 
because  of  the  many  other  problems  con- 
fronting the  Commerce  head,  and  in 
order  to  give  the  Department  Radio 
Officials  and  the  representatives  of  the 
industry  time  to  draw  up  plans  and  sug- 
gestions to  be  considered  by  the  general 
conference. 

Officials  of  the  Department  believe 
one  of  the  most  interesting  questions  to 
be  discussed  will  be  the  limitation  of 
power,  or  perhaps  the  removal  of  the 
power  limitations  now  in  force,  if  public 
sentiment  backed  by  experiments  now 
going  on  indicate  that  there  is  no  reason 
for  limiting  the  power  of  broadcasting 
stations. 

Forty-two  broadcasting  stations  are 
now  using  1,000  or  more  watts;  seven 
of  them  are  operating  with  at  least 
5KW,  a  once  dreaded  figure,  although  no 
serious  complaints  have  been  received 
since  these  broadcasters  went  on  the  air. 
Two  stations  are  now  experimenting 
with,  or  about  to  try,  50  KW.  WGY's 
tests  seem  to  have  been  satisfactory, 
and  it  is  said  that  WJZ,  the  Radio  Cor- 
poration's new  high-power  project  located 
outside    of    New    York,    will   soon    start 


testing  its  new  50  KW  set.  Other  sta- 
tions are  preparing  to  try  out  broad- 
casting with  5KW  or  more.  It  is  esti- 
mated that  at  least  twenty  B  stations 
are  equipped  to  go  to  5KW,  although 
only  eight  have  been  licensed  to  do  so  at 
this  writing. 

Whether  or  not  the  recent  increase  in 
power  will  continue  to  spread  over  the 
country  is  not  known;  neither  is  it 
definitely  known  how  far  apart  very 
high-powered  stations  must  be  located 
to  prevent  undue  interference,  or  how 
great  a  separation  there  must  be  between 
the  wave  lengths  they  employ. 

If  a  large  number  of  the  present  sta- 
tions went  to  high  power,  regardless  of 
their  proximity  to  each  other  or  the 
relationship  of  their  broadcasting  chan- 
nels, there  would  probably  be  difficulty 
in  separating  them.  It  may  be  found 
desirable  to  locate  the  very  high-powered 
stations  in  distant  states  or  perhaps  a 
hundred  or  two  miles  apart,  assigning 
them  wave  lengths  separated  by  fifty 
meters  or  more.  This  would  of  course 
tend  to  limit  the  number  of  such  stations, 
but  this  will  probably  adjust  itself. 
There  will  not  be  many  operators  rich 
enough  to  build  and  maintain  50  KW 
stations,  which  cost  almost  a  half  mil- 
lion  dollars  to  install. 

Nevertheless,  the  views  of  the  public 
will  be  sought,  as  well  as  those  of  the 
broadcasters,  before  any  definite  or 
limiting  action  on  power  is  taken  by  the 
Department.  It  may  be  necessary  to 
have  the  old  radio  regulations  and  even 
the  laws  amended,  and  it  is  understood 
that  the  Department  will  probably 
have  a  tentative  radio  law  in  shape  for 
discussion  by  the  time  the  conference 
convenes. 

Secretary  Hoover  is  a  great  believer  in 
radio  as  a  public  service  and  he  is  also 
disposed  to  let  the  public  in  on  any  hear- 
ing which  will  affect  such  a  public  service 
— hence  the  Fall  conference  is  a  certainty. 


Professional  Set  Builders 
Organize 

Custom-built  receivers  are  to  be  pro- 
moted on  an  extensive  scale  if  plans  of 
the  newly  organized  Professional  Radio 
Set  Builders  Association  are  carried 
through.  This  organization  elected  offi- 
cers on  July  24th,  at  its  first  meeting 
held  in  the  offices  of  the  Allen  D.  Card- 
well  Mfg.  Corp'n,  in  Brooklyn. 

Despite  the  dullness  of  the  Summer 
season,  unusual  interest  was  displayed 
in  getting  the  new  body  under  way. 
Plans  involve  newspaper  advertising,  a 
testing  laboratory,  publicity  bureau,  and 
a  general  organization  to  benefit  the 
dealers  and  professional  men  who  build 
sets  to  order,  some  of  the  members  sell  as 
many  as  a  thousand  sets  a  season,  others 
only  a  few. 

The  association  particularly  is  endeav- 
oring to  counteract  the  tendency  of  the 
non-technical  public  to  buy  inferior 
apparatus  offered  at  prices  inconsistent 
with  good  design  and  service.  It  hopes 
to  educate  the  public  to  accept  radio  sets 
which  afford  more  service  though  costing 
more  initially. 

Officers  of  the  association  have  been 
elected  with  headquarters  at  71-73  West 
Broadway,  New  York  City.  A  member- 
ship committee  was  appointed  to  run 
up  the  list  of  active  supporters  and  to 
start  _  organizing  _ local  chapters  of  the 
association  in  cities  all  over  the  United 
States.  It  is  planned  eventually  to 
standardize  the  conditions  of  member- 
ship so  that  the  public  are  guaranteed 
service  and  satisfaction  on  any  sets 
turned  out  by  members  of  the  association. 

A  number  of  manufacturers  of  high 
grade  radio  apparatus  have  endorsed 
the  ideals  of  the  association  and  are  con- 
tributing to  its  support. 


End  your  Radio  Troubles  for  30c  in  Stamps 

We  have  laid  aside  a  limited  number  of  back  issues  of  RADIO  AGE  for  your  use.  Below  are  listed  hookups  to  be  found 
in  these  volumes.  Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired.  The  supply  is  limited,  so  enrich  your 
store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 


January,  1924 

— Tuning  Out  Interference — Wove  Traps — Eliminators 

— Filters 

— A  Junior  Super-Heterodyne. 

— Push-Pull  Amplifier. 

— Rosenbloom  Circuit. 

March,  1924 

— An  Eight-Tube  Super-Heterodyne. 
— A  simple,  low  loss  tuner. 
— A  Tuned  Radio  Frequency  Aplifier. 
— Simple  Reflex  Set. 

April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated). 

— A  Ten  Dollar  Receiver. 

— Anti-Body  Capacity  Hookups. 

— Reflexing  the  Three-Circuit  Tuner. 

— Index  and  first  two  installments  of  Radio  Age  Data  Sheets. 

May,  1924. 

— Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

— Important  Factors  in  Constructing  a  Super-Heterodyne. 

— A  Universal  Amplifier. 

— A  Sure  Fire  Reflex  Set. 

- — Adding  Radio  and  Audio  to  Baby  Heterodyne. 

— Radio  Age  Data  Sheets. 

July,  1924 

— A  Portable  Toned  Impedance  Reflex. 

— Operating  Detector  Tube  by  Grid  Bias. 

— A  Three-Tube  Wizard  Circuit. 

— Data  Sheets. 

August,  1924 

— Breaking  Into  Radio  Without  a  Diagram. 

— The  English  4-Element  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 

RADIO  AGE,  INC., 


September,  1924 

— How  careful  Mounting  Will  Improve  Reception. 

• — One  Tuning  Control  for  Hair 'a  Breadth  Selectivity. 

— Four  Pages  of  Real  Blueprints  of  a  New  Baby  Heterodyne 
and  an  Aperiodic  Variometer  Set. 

— Data  Sheets. 

October,  1924 

— An  Easily  Made  Super- Het. 

— Two  Radio  and  Two  Audio  for  Clear  Tone. 

— A  Simple  Regenerative  Set. 

— The  Ultradyne  for  Real  DX. 

— Real  Blueprints  of  a  3-Tube  Neutrodyne  and  a  Midget 
Reflex  Set. 

November,   1924 

— Blueprints  of  a  Single  Tube  Loop  Set  and  a  Capacity  Feed- 
back Receiver. 

— A  3-Tube  Low  Loss  Regenerator. 

— Mastering  the  3-Circuit  Tuner. 

December,  1924 

— Blueprints  of  a  New  8-Tube  Super- Heterodyne. 

— How  to  Make  a  Receiver  that  Minimizes  Static 

— A  Trans-Atlantic  DX  Receiver. 

— How  to  Make  a  Home  Made  Battery  Charger  and  a  Loud 
Speaker  at  a  Small  Cost. 

January,  1925 

— A  Reflexed  Neutrodyne. 

— A  Six  Tube  Super-Het. 

— An  Efficient  Portable  Set. 

— A  Tuned  Plate  Regenerator 

— Making  a  Station- Finder. 

February.  1925. 

— A  Sure  Shot  Super-Het. 

— A  Three  Circuit  Regenerator. 

— A  Real,  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex. 

March,  1925. 

— A  Permanent  Sup-Het. 

—A  5-Tube  R.  F.  Receiver. 

— How  to  Wind  Low  Loss  Coils. 

— A  Short  Wave  Receiver. 

— Blueprints  of  a  Two-Tube  Ultra  Audion  and  a  Regenerative 
Reflex. 


April,  1925 

— A  3-Tube  Portable  Set. 

— "B"  Voltage  from  the  A.  C.  Socket. 

— An  Amplifier  for  th  3-Circuit  Tuner. 

— Blueprints  of  a  Five-Tube  Radio  Frequency  Receiver. 

May,  1925. 

— A  "Quiet"  Regenerator. 

— A  Power  Supply  Receiver. 

— How  to  Make  a  Tube-Tester. 

— A  Unique  Super-Het  and  an  Improved  Reinarta. 

— A  Six  Tube  Portable  Receiver  Illustrated  with  Blueprints 

June,  1925. 

— Reducing  Static  Disturbances 

— A  Seven- Tube  Super-Heterodyne. 

— The  Double  Grid  Tube  in  Ordinary  Sets. 

— Browning- Drake  Receiver. 

— Overcoming  Oscillations  in  the  Roberts  Receiver, 

— An  Ideal  Set  in  Practical  Form, 

— Soldering  Secrete. 

July,  1925 

— Learning  Tube  Characteristics. 

— How  Much  Coupling? 

— The  Six-Tube  Super-Autodyne. 

—A  Simplified  Portable  Super-Het. 

— Blueprints  of  Conventional  Radio. 

— Symbols  and  Crystal  Detector  Circuit. 

August,  1925 — 50c  per  copy 

— How  to  Attain  Smooth  Tuning. 

— Alternating  Current  Tubes. 

— Deciding  on  a  Portable  Super — 

— And  a  big  60-page  blueprint  section,  in  which  is  contained 
blueprints  of  all  the  basic  circuits  from  which  all  radio 
hookups  have  been  developed  since  the  birth  of  Radio. 

September,  1925. 

— Thirty-one  ways  to  prevent  self-oscillations. 
— Tuning  efficiency  with  two  controls 
— Ideal  Audio  Amplifier  Circuits. 
— Blueprint  section. 


500  N.  DEARBORN  ST.,  CHICAGO 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour         43 


Hoolc^xip^s 

npHE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  is 
■*•  contributed  by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


Conducted  by  Fred  Hill 

REPRESENTING  southern  recep- 
tion, Robert  Barbee,  6114  Caddo 
-  Ave.,  Cedar  Grove,  La.,  submits 
a  list  of  stations  picked  up  on  a  factory 
built  set,  the  list  ranging  from  the  East 
to  the  West  coast. 


Interesting  daylight  reception  is  re- 
ported by  Robert  C.  Potter,  R.  R.  3, 
Beamsville,  Ont.,  Canada,  who  is  already 
a  member  of  the  Dial  Twisters.  He  has 
picked  up  47  stations  in  all  on  a  crystal 
set.  His  daylight  list  includes  several 
Canadians  and  WBZ,  WGY,  KDKA, 
WEAR,  WTAM  and  WMAK,  all  of 
which  makes  an  excellent  record  for 
some  of  our  crystal  gazers  in  the  States 
to  attempt  to  beat. 


H.  Predosa,  2864  Lincoln  Ave.,  Chi- 
cago, 111.,  writes  as  follows:  "Received 
your  answer  in  regard  to  the  three  tube 
neutrodyne  and  want  to  congratulate 
you  on  your  promptness.  The  reason 
for  this  is  that  one  time  I  wrote  to  the 
Magazine  for  a  little  informa- 
tion and  had  to  wait  two  months  for  a 
reply,  and  the  nature  of  the  question 
was  similar  to  the  one  I  wrote  you." 
All  of  which  more  or  less  confirms  our 
opinion  that  when  a  fan  writes  in,  he 
desires  an  answer.  The  staff  has  made 
it  a  point  to  answer  all  questions  just 
as  quickly  as  it  is  possible  to  do  so. 


Our  genial  English  informant,  R.  A. 
Ganatt,  17  Lome  Road,  Stroud  Green 
N.  4,  England,  who  furnished  us  with  a 
bit  of  gossip  from  his  side  of  the  Atlantic 
in  the  August  issue,  gives  us  some  more 
data  of  interest  to  our  radio  fans  who 
have  a  flair  for  radio's  international 
scope: 

British  tubes  at  last  are  being  made 
with  the  standard  four  prong  base 
similar  to  the  type  to  which  the  Ameri- 
can listeners  are  accustomed. 

Glass  panels  instead  of  bakelite  are 
now  the  thing  -in  France  and  Britain. 
(Oh,  the  weary  hours  of  drilling!) 

Croydon  Aerodrome,  near  London, 
call  GED,  uses  a  wavelength  of  900 
meters.  (Not  much  chance  for  the 
Americans  to  log  him,  on  account  of  the 
upper  limits  of  most  sets  being  550 
meters.  However,  there  is  some  chance 
for  the  dyed-in-the-wool  experimenters 
with  separate  coils  for  the  different  bands. 

"Secret  Wireless,  Ltd.,"  is  the  name 
of  a  newly  organized  company  in  Eng- 
land   contemplating    broadcasting    to    a 


Name 
Walton  Van  Winkle,  Jr. 
Arol  Schmidt 

CONTRIBUTORS 

Address 
..2528  Benvenue  Ave 
.484  40th  St 

City 
Berkeley,  Calif. 

n. 

Y. 
Pa. 

Va. 
,  Can. 

Y. 

Can. 
Can. 

Albert  W.  Small 

DIAL  TWISTERS 

..1210  12th  St.,  N.  W 

6114  Caddo  Ave.... 

Washington,  D.  ( 

Vialis  F.  Walz 

Chas.  W.  Justus- 

George  Wistow 

J.  P.  Morrison,  Jr 

Joseph  H.  Miller. 

Winston  Klontz 

.2072  Greenwood  Ave... 

.95  Leslie  St 

...1711  South  Peoria 

.217  Pearl  St 

Glen  Haven,  Wis 

Toledo,  Ohio 

Tulsa,  Okla. 

Brooklyn,  N.  Y. 
Mt.  Morris,  111. 

C.  C.  Schlegel 

J.  D.  Johnston. 

Bertram  Susdorf 

John  W.  Wilson,  Jr 

Willis  Stratton 

J.  M.  Landon. 

Harold  Huffman 

Chas.  E.  Ross . 

Fred  C.  Favre 

George  Tucker 

.U.  S.  S.  Denver.... 

.1764  Gilpin  St 

R.  F.  D.  Route  1 

.113  Scoville  Way 

Kenesaw,  Nebr. 

New  York,  N.  Y 
Rantoul,  111. 

Denver,  Colo. 

Canandaigau,  N. 

N.  S.  Pittsburgh, 

Box  4,  Van  Dyke  P.  O 
.   Elgin  State  Hosp 

..1257  Benitean  Ave 

.36  Angeles  St 

Van  Dyke,  Mich 
Elgin,  111. 

Cressville,  N.  J. 

Detroit,  Mich. 

Pal- 

London,  Eng. 

Detroit,  Mich. 
Parkersburg,  W. 

V.  Alcock 

...Lynton   Green  Lanes, 

John  Skewis 

mers  Green 

...1731  Beaufalt  Ave 

...1716  East  7th  St 

G.  M.  Hewson.. 

Elmer  H.  Glafke 

F.  McGarr 

...Drawer  705 

...202  Rumely  St 

Ray  Masterson 

T.  C.  J.  Dixon. 

...744  Greene  St... 

...1913  Decatur  St... 

Marietta,  Ohio 

Willie  R.  Jones 

...1249  Wood  St..... 

St.  Stephen  N.  B. 
Rsgb.,  Germany 

Moncton,  N.  B., 
Paris,  Tex. 

Mrs.  Frank  A.  Duston 

G.  V.  Skal 

R.  F.  Cochrane 

..Box  424 

...Ober  Schreiberhau 

..1303  Main  St 

paying  audience  who  use  special  adapters 
for  the  broadcast.  It  is  expected  that 
theater  broadcasts  will  be  furnished 
patrons  of  the  company.  (It  may  work 
over  there,  but  where's  the  kick  in  having 
your  stuff  piped  nto  the  house  like  gas 
or  water?     Eh  wot?) 

Ganatt  says  in  the  majority  of  cases 
where  two  way  communication  between 
England  and  America  has  been  ac- 
complished by  amateurs,  such  work  has 
been  done  by  the  English  amateurs 
living  in  suburban  districts  and  not  in 
cities  like  London  and  Manchester,  where 
there  is  the  worst  shielding  imaginable. 
(Some  of  our  friends  in  England  should 
try  Chicago's  Loop  district  for  trans- 
mission. It's  like  transmitting  under- 
ground.) 

J.  Robert  Chandler,  Arcade  Box  1004, 


Los  Angeles,  Calif.,  tells  us:  "I  have 
read  your  RADIO  AGE  for  July  from 
cover  to  cover  and  get  more  real  radio 
news  than  from  any  magazine  for  a  long 
time;  and  I  read  most  of  the  magazines. 
In  regard  to  the  best  type  of  set,  I  be- 
lieve if  I  lived  in  a  big  city  a  regenerative 
set  would  do  for  me;  if  in  the  country 
a  5  tube  r.  f.  set  and  if  real  far  away  a 
super-het."  The  DX  list  accompanying 
the  letter  entitles  Mr.  Chandler  to  the 
DT    emblem. 


B.  Odell,  270  Odgen  St.,  Orange,  N.  J., 
says  he  is  quite  pleased  with  the  8  tube 
super  he  built  from  the  description  by 
Calcaterra  in  the  May  number  of  RADIO 
AGE. 


O.   L.   Overton,   Station   G,    Memphis, 
Tenn.,  sends  in  his  idea  of  a  "go-getter" 


44 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


Fig.  I. The  picture  above  shows  Herbert  Hiley,  oftheBritish  stationG21  H,  situated  at  Keigh- 
ley,  Yorkshire,  who  has  been  successful  in  establishing  communication  with  M.  Fresni, 
Rua  Aswaldo  Cruz,  Nieteroky,  Brazil,  a  distance  of  5400  miles  with  a  wavelength  of 
42  meters  and  15  watts  in  the  antenna,  the  circuit  used  being  a  Hartley  loose  coupled. 
Mr.  Hiley  is  shown  logging  a  station.  The  photograph  is  by  courtesy  of  G.  Crowther, 
28  Cark  Road,   Keighley,  England. 


set  which  is  a  variant  of  the  well  known 
Weagant,  single  circuited.  He  reports 
excellent  results  with  it,  as  many  other 
fans  have. 


Vialis  F.  Walz,  Glen  Haven,  Wis., 
found  the  ultra-audion  circuit  in  our 
"Radio  Rodeo"  in  August  and  has  been 
having  great  luck  with  it.  The  panel 
was  three  ply  board;  it  was  hooked  up 
with  bell  wire  and  no  soldering  done. 
After  getting  a  nifty  bunch  of  stations, 
Mr.  Walz  intends  making  the  set  over 
in  permanent  form  for  use  in  chasing 
DX  stations.  The  ability  of  the  ultra- 
audion  to  transmit  signals  with  a  micro- 
phone in  the  ground  lead  depends  en- 
tirely upon  the  antenna,  ground  and  the 
amount  of  power  which  the  tube  will 
handle.  Of  course,  to  do  any  trans- 
mitting it  will  be  necessary  to  have  a 
transmitting  license  from  the  U.  S.  De- 
partment of  Commerce.  Application 
for  such  may  be  made  to  Mr.  E.  A. 
Beane,  Radio  Supervisor,  Ninth  Radio 
Disgrict,  Federal  Bldg.,  Chicago,  111. 
The  above  information  is  given  for  Mr. 
Walz  and  the  host  of  others  who  have 
written  in  asking  regarding  the  use  of  a 
microphone  in  the  ground  lead.  Pri- 
marily the  set  would  be  only  a  very  short 
range   transmitter. 


feel  that  way,  too.     Let's  see  what  they 
have    to    say. 

George  Wistow,  95  Leslie  St.,  Toronto, 
Ont.,  Canada,  must  have  an  adding 
machine  running  hot,  for  he  reports 
hearing  265  stations  within  a  span  of 
eight  nights,  the  list  showing  an  average 
of  something  like  thirty  stations  a  night. 


For  the  benefit  of  our  transmitting 
fans  and  our  general  readers,  we  are 
running  in  this  section  a  picture  of  the 
station  of  Herbert  Hiley,  British  G21H, 
located  at  Keighley,  Yorkshire,  who  has 
been  successful  in  establishing  com- 
munication with  M.  Fresni,  Rua  Aswaldo 
Cruz,  Nieteroky,  Brazil.  The  distance 
in  this  case  was  5400  miles.  The  wave 
used  was  42  meters  and  the  power,  15 
watts,  output.  The  circuit  used  was  a 
Hartley    loose-coupled. 


Charles  W.  Justus,  2072  Greenwood 
Ave.,  Toledo,  Ohio,  remarks  that  the 
coast  to  coast  set  which  was  published 
in  the  March  issue  should  be  included 
in  the  blueprint  section  which  this  maga- 
zine maintains  each  month.  He  feels 
that  such  good  hookups  should  be  shown 
in  the  prints.    Maybe  some  of  our  readers 


Using  a  regenerative  set  with  trans- 
former and  resistance  coupled  audio 
amplification,  Walter  Van  Winkle,  Jr., 
2528  Benvenue  Ave.,  Berkeley,  Calif., 
whiles  away  the  hours  logging  the  two 
coasts,  despite  the  presnce  of  about  fifteen 
locals  in  the  Bay  counties.  The  re- 
sistance coupled  amplification  and  the 
push-pull  arrangement  has  been  touched 
upon  previously  by  Mr.  Rathbun  in 
the  September  blueprints. 


,  J.  P.  Morrison,  Jr.,  1711  South  Peoria, 
Tulsa,  Okla.,  sends  us  an  excellent  list 
of  stations  heard  during  the  Summer. 
He  is  a  recent  convert  to  RADIO  AGE 
and  thinks  ours  the  best  magazine  cater- 
ing to  the  broadcast  listener. 


Joseph  H.  Miller,  217  Pearl  St.,  Brook- 
lyn, N.  Y.,  working  through  local  inter- 
ference, has  a  commendable  list  showing 
a  great  deal  of  perseverance.  The  cir- 
cuit is  a  three  circuit  type  with  only  one 
tube.  Before  the  single  tuber  came 
into  being,  Mr.  Miller  was  a  confirmed 
crystal  fan.  In  addition  to  the  broad- 
casting stations,  a  number  of  "hams" 
are  included  in  the  list. 


Using  a  single  tuber,  Winston  Klontz, 
Mt.  Morris,  111.,  furnishes  a  worthy  list 
of  radio  reception,  taking  in  the  two 
coasts    and    Canada. 


Over  two  hundred  American  broad- 
casters, three  hundred  some  odd  ama- 
teurs in  the  U.  S.  and  fifty  or  more 
abroad,  to  say  nothing  of  2EH  Scotland, 
5NO,  Newcastle,  Eng.,  YL,  Paris,  France, 
4AG,  Dunedin,  New  Zealand  and  CBS, 
Buenos  Aires,  Willis  Stratton,  R.  F.  D. 
Route  No.  1,  Canadaigua,  N.  Y.,  easily 
qualifies  for  DX  honors  and  the  coveted 
DT  button.     Fine  biz,  we  say. 


C.  G.  Schlegel,  of  Kenesaw,  Neb., 
asks  us  to  give  some  of  the  superdyne 
circuits,  believing  that  our  August  num- 
ber catered  principally  to  the  newly 
initiated  instead  of  the  dyed-in-the-wool 
experimenter.  The  circuit  to  which  he 
refers  is  not  so  much  a  circuit  as  it  is  a 
trade    name. 


Writing  from  the  U.  S.  S.  Denver, 
care  Postmaster,  New  York,  N.  Y., 
J.  D.  Johnston  relates  his  experiences 
with  radio,  beginning  with  a  crystal  set 
and  thence  via  the  usual  route  to  a  three 
tube  regenerative,  a  five  tube  neutro- 
dyne  and  finally  the  super-het,  using 
the  modulation  principle  instead  of  the 
conventional  double  detection. 


Attesting  the  popularity  of  the  one 
tube  regenerative,  we  have  John  W. 
Wilson,  Jr.,  of  1764  Gilpin  St.,  Denver, 
Col.,  sending  in  his  application  for  the 
DT  honors.  We  often  wonder  if  the 
possessor  of  a  five  tube  set  or  even  a 
super  ever  really  gets  the  thrill  out  of  the 
game  that  he  did  when  he  first  listened 
on  a  pair  of  "cans"  to  a  weakling  signal 
from  a  distant  broadcaster. 


Being  anxious  to  hear  what  is  trans- 
piring on  the  lower  wave  bands,  Bertrand 
Susdorf,  of  Rantoul,  111.,  rigged  up  a 
short  waver  and  picks  up  KDKA,  WGY 
and  an  occasional  other  station  in  the 
region  below  100  meters.  In  addition 
he  has  a  three  circuit  set  used  for  the 
standard    broadcast     band. 


J.  W.  Landon,  113  Scoville  Way, 
N.  S.  Pittsburgh,  Pa.,  on  seeing  in  a 
recent  number  that  William  J.  Sergeant 
was  interested  in  a  four  tube  set  that 
would  tune  sharp,  furnished  Mr.  Sergeant 
with  the  diagram  and  constants  of  the 
circuit  he  is  using.  Just  another  indica- 
tion of  the  wonderful  bond  of  friendship 
that  exists  between  members  of  the  same 
fraternity. 

We  almost  fell  out  of  our  chair  when 
the  following  letter  appeared  at  the 
RADIO  AGE  office:  "At  last  I  have 
found   what    I    wanted.      It   is   'RADIO 


RADIO  AGE  for  October,  1925 


Send  for  I  his 


The  Magazine  of  the  Hour        45 


S 


BARGAINS 


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46 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


AGE,'  the  radio  magazine  with  blue- 
prints, not  overstuffed  with  technical 
terms  and  not  entirely  neglecting  the 
beginner.  I  have  been  a  fan  for  five 
years  and  have  been  getting  most  of  the 
radio  periodicals.  Recently  I  stopped 
buying  the  artists'  pictures  and  out- 
landish histories  of  radio  until  now  I 
am  only  receiving  one,  and  as  soon  a 
my  subscription  expires  that  magazine 
will  expire  with  it  as  far  as  I  am  con- 
cerned. Today  was  the  first  time  I  saw 
your  magazine  and  I  have  only  had  time 
to  read  one  article;  but  it  appeals  to 
me  so  I  want  to  hasten  to  get  on  your 
subscription  list.  I  see  the  wisdom  of 
your  not  naming  the  firms  names  or 
any  of  the  parts  used  in  your  articles, 
but  I  am  so  taken  with  Mr.  Rathbun's 
article  on  the  8  tube  super  that  I  wish 
to   build   it. 

"This  one  article  is  worth  more  than 
the  yearly  subscription  cost." 

This  was  written  by  James  M.  Ben- 
nett, P.  0.  Box  1431,  Weirton,  West 
Virginia,  and  we'll  say  it  is  some  letter. 

Harold  Huffman,  P.  O.  Box  4,  Van 
Dyke,  Mich.,  favors  us  with  a  list  of 
stations  picked  up  on  a  single  tube  set, 
using  a  split  variometer.  The  list  in- 
cludes some   Canadians. 

"Good  parts"  is  the  reason  assigned  by 
F.  C.  Favre  for  his  success  with  home 
made  radio  sets  and  the  number  of  sta- 
tions logged  according  to  a  letter  received 
from  him  at  Cressville,  N.  J. 


No,  Geraldine,  there  are  no  battery 
solutions  that  take  the  place  of  an  elec- 
tric charge  for  your  battery.  A  storage 
battery  is  a  typical  example  of  the  "put 
and  take"  game.  You  take  out  so  much 
and  you  must  put  back  so  much.  Since 
you  take  current  you  must  replace  cur- 
rent. You  don't  take  the  solution  so 
why  should  you  figure  on  adding  solu- 
tion? 


would  like  to  announce  that  the  D.  T. 
buttons  are  sent  out  every  month  just 
about  the  time  the  issue  is  run  off  the 
press.  Sometimes  there  is  a  little  delay 
incident  to  a  press  of  business,  but  as  a 
rule  by  the  time  the  issue  is  on  the  news 
stands  your  button  should  have  arrived. 


the  distances  are  all  in  excess  of  a  thou- 
sand miles.     Que  tal,   amigo? 


George  Tucker,  1257  Bevitean  Ave., 
Detroit,  Mich.,  with  a  factory  built  set 
logged  fourteen  stations  in  a  half  hour. 
Since  seeing  the  August  number,  he  is 
interested  in  a  super  to  see  if  he  can  better 
his  record. 


Arol  Schmidt,  484  40th  St.,  Mil- 
waukee, Wis.,  favors  us  with  a  letter 
telling  about  Mr.  Dunwoodie,  at  Apia, 
Samoa,  who  regularly  receives  KYW, 
KFKX,  and  who  also  has  logged 
Portland,  Ore.,  and  a  Canadian  station, 
the  distance  being  something  on  the 
order  of  eight  thousand  miles.  Mr. 
Schmidt  encloses  a  diagram  of  the  re- 
ceiver used  by  Mr.  Dunwoodie,  which  is  a 
two  stage  radio  and  a  detector,  the  latter 
coupled  capacitatively  from  the  grid  of 
the  detector  to  the  plate  inductance  of  the 
preceding  tube.  The  detector  is  regenera- 
tive, a  la  Armstrong.  The  antenna  coil 
is  35  turns,  its  secondary,  50  turns  span- 
ned by  a  .0005;  the  output  of  the  first 
tube  goes  through  a  r.  f.  transformer,  un- 
tuned, to  the  grid  of  the  second  tube. 
The  plate  inductance  of  the  second  tube, 
which  is  also  the  secondary  of  the  detec- 
tor circuit,  contains  from  40  to  60  turns, 
bridged  by  a  .0005  mfd  condenser.  The 
tickler  coil  has  75  turns.  In  Mr.  Dun- 
woodie's  case  spiderweb  coils  are  used; 
any  tubes  are  suitable  and  only  45  volts 
is  necessary  for  a  B  battery.  The  re- 
turn from  the  first  grid  is  put  on  the 
slider  of  a  400  ohm  potentiometer.  A 
diagram  of  the  circuit  is  shown  in  Figure 
2. 


For  the  benefit  of  James  R.  Harts- 
horne,  2258  Bedford  Ave.,  Brooklyn,  N. 
Y.,  and  a  host  of  other  Dial  Twisters,  we 


A  one  tube  Reinartz,  home  made,  is 
all  that  Ramon  Quesada,  36  Angeles  St., 
Havana,  Cuba,  requires  to  bring  in  both 
the  coasts,  Mexico  and  Canada.  The 
list  of  stations  logged  is  not  very  long  but 


RADIO  AGE  has  one  Dial  Twister 
(he  will  be  when  this  issue  is  off  the  press) 
who  receives  all  kinds  of  European 
stations.  Don't  all  jump  at  once.  He 
is  a  sea-going  operator,  V.  Alcock, 
Lynton,  Green  Lanes,  Palmers  Green, 
London,  England,  who  seems  to  run 
London  to  Galveston  and  return.  In 
addition  to  all  the  European  stations,  he 
picked  up  a  flock  of  the  American  sta- 
tions, quite  a  few  Canadians,  Mexicans 
and  a  Cuban,  all  of  these  on  the  voyage 
previously  mentioned.  Many  a  D.  T. 
would  give  his  right  arm  for  a  chance  to 
cross  the  Atlantic  with  nothing  to  do 
but  log  'em  on  all  sides. 


John  Skewis,  1731  Beaufalt  Ave., 
Detroit,  Mich.,  tells  us  he  built  about 
twenty  sets  last  winter,  and  has  just 
finished  the  set  shown  on  page  23  of  the 
February  Radio  Age,  which  he  says  beats 
them  all.  Mr.  Skewis  is  a  shut-in  and 
has  plenty  of  time  on  his  hands.  He 
says:  "It's  a  pleasure  for  me  to  take  one 
of  your  hookups  and  construct  it,  as  I 
have  full  confidence  in  its  being  as  stated 
in  your  magazine."  Using  the  set  re- 
ferred to  on  page  23  of  the  Febru- 
ary Radio  Age,  he  picked  up  CNRE, 
Edmonton,  Alberta,  Canada,  about  1500 
miles  from  Detroit,  bringing  in  the  sta- 
tion on  the  loud  speaker.  He  now  only 
awaits  the  coming  of  good  DX  weather 
to  get  up  a  DX  list  that  will  knock  'em 
cold.      That's  the  spirit. 


Albert  W.  Small,  1210  Twelfth  St., 
N.  W.,  Washington,  D.  C,  has  fine 
results  with  the  ultra-audion,  using 
either  the  resistance  coupled  or  trans- 
former coupled  audio  amplification. 


Okey  Deem,  1716  East  7th  St., 
Parkersburg,  West  Virginia,  will  not  be 
weaned  from  the  Armstrong  single  cir- 
cuit regenerative,  which  brings  him  all 
manner  of  signals,  and  whose  list  entitles 
him  to  one  of  the  buttons. 


1   LI 


ffFr 


.  oe ' 


r^2 


-J,   5  4-0<?    OHA\S 


trtzf 


fone 


Fig.  2.  Many  of  you  have  wondered  what  Mr.  Dunwoodie  at  Apia,  Samoa,  about  8,000  miles  from  Chicago,  used  for  reception, 
Well,  the  story  is  shown  above.  Two  stages  of  radio  and  regenerative  detector.  The  diagram  is  self-explanatory.  Spiderwebs  may  be 
used  for  the  coils,  or  any  other  form  of  good  inductance.     The  set  will  work  with  any  tubes  and  only  45  volts  B  battery  is  required. 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour        47 


Ward's  New  Radio  Catalogue 

Is  Yours  Free 


Yours  Free — the  newest,  most  in- 
teresting book  published  on  Radio. 
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For  53  years  we  have  sold  only  quality  merchan- 
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*     TfUd  and  Approvtd  bn  RADIO  AG!     * 


48 


RADIO  AGE  for  October,  1925 


Miatornott 


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The  Magazine  of  the  Hour 

An  Organized  Warfare 
Against  Fading 

(Continued  from  page  22) 
with  primary  inserted  in  the  plate  circuit 
of  the  second  detector  of  a  super-hetero- 
dyne, the  proposed  rectifying  unit  can 
be  added  either  within  or  outside  the 
receiving  set  by  the  arrangement  in- 
dicated in  Figure  1  of  the  circuit  diagram. 
Here  it  will  be  noted  that  the  audio- 
frequency transformer  with  primary 
shunted  by  a  condenser  to  by-pass  radio- 
frequency  currents  is  left  in  the  circuit 
so  that  the  telephones  may  be  used  in 
an  audio  stage  for  monitoring  purposes. 

"Where  the  wiring  of  the  receiving 
set  is  inaccessible,  as  with  the  'Radiola 
8,'  the  primary  of  the  extra  intermediate- 
frequency  transformer  (42  kilocycles) 
may  be  inserted  by  means  of  an  adapter 
which  raises  the  electron  tube  so  as  to 
allow  opening  the  plate  circuit  between 
the  socket  and  the  tube  itself,  as  shown 
in  Figure  2  on  the  diagram.  (Adapter 
may  be  constructed  from  the  base  of 
an  old  UV-199  tube  and  any  adapter 
made  for  this  type  of  vacuum  tube. 
The  second  detector  of  the  'Radiola' 
is  the  third  tube  from  the  left  when 
facing  the  cabinet.)  By  employing  only 
the  first  stage  of  audio  amplification 
for  the  monitoring  telephones  it  is 
possible  to  utilize  the  vacuum  tube  of 
the  second  audio  stage  (at  the  extreme 
left  when  facing  the  set)  for  the  two- 
electrode  rectifier  by  making  another 
adapter  which  raises  the  tube  and  leaves 
only  the  filament  connections  in  cir- 
cuit. 

"A  voltmeter  should  be  placed  across 
the  filaments  of  all  vacuum  tubes  and 
voltages  should  be  kept  the  same  through- 
out all  test  periods.  This  applies  also 
to  the  two-electrode  tube,  if  used.  If  the 
same  filament  battery  and  the  same  type 
of  tubes  are  used  for  rectifier  and  receiv- 
ing set  one  voltmeter  will  suffice  for  all. 
'B'  batteries  should  be  in  condition  to 
insure  constant  voltage  throughout  a 
test    period. 

"Some  observers  have  had  difficulty 
with  a  serious  lag  in  the  response  of  the 
galvanometer  pointer.  This  effect  can 
usually  be  minimized  by  critical  damp- 
ing. Probably  the  easiest  way  to  accom- 
plish this  is  to  shunt  a  resistance  box 
across  the  galvanometer  while  in  circuit 
and  vary  the  resistance  until  the  pointer 
responds  quickly  to  current  variations. 
In  case  a  shunt  resistance  fails,  a  series 
resistance  may  serve  the  purpose.  The 
former  should  correct  the  vibration 
effect;  the  latter  is  needed  in  case  the 
pointer    lags. 

"When  recording  is  done  on  a  con- 
tinuous tape  the  exact  time  should  be 
indicated  on  the  record  approximately 
every  15  minutes  as  a  means  of  checking 
for  later  comparisons.  Where  readings 
are  taken  and  plotted  later  it  will  natur- 
ally be  necessary  to  check  the  time  much 
more  closely  as  deflections  will  be  read 
several  times  a  minute.  Changes  in 
receiver  amplification  made  during  a 
record  should  be  noted,  together  with 
the  approximate  ratio  of  change. 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour         49 

■h— .— ,  ■■■■  isa 


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RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


84 
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Where  Does  the  Power  Come 
From? 

(Continued  from  page  14) 
phone  circuit  varies.  Naturally,  the 
source  of  potential  used  must  be  un- 
varying, for  a  fluctuating  potential 
would  cause  noisy  and  distorted  trans- 
mission. For  this  reason,  generators 
are  never  used  in  microphone  circuits 
because  of  fluctuations  which  are  neces- 
sarily impressed  upon  the  output.  Bat- 
teries of  some  kind  are  always  employed. 
When  faithfulness  of  reproduction 
is  attained  in  transmission,  the  micro- 
phone has  responded  accurately  to  an 
air  wave  form  of  extraordinary  com- 
plexity, with  full  consideration  to  over- 
tones or  harmonics,  correctly  propor- 
tioned according  to  the  character  of  the 
various  instruments.  The  current  supply 
to  the  microphone  supply  has  been  un- 
varying, without  tending  to  increase  the 
energy  on  some  frequencies  at  the  expense 
of  others.  Billions  of  chemical  actions 
have  contributed  to  an  even  and  re- 
sponsive potential  supply,  so  that  the 
finest  graduations  of  sound  waves  have 
been  translated  into  current  variations. 
A.  F.  Circuits 

BECAUSE  the  frequencies  involved 
in  the  microphone  circuit  when 
passed  through  telephone  receivers  cause 
sound  waves  to  which  the  ear  responds, 
they  are  termed  "audio-frequency"  cur- 
rents. They  are  identical  with  those 
transmitted  over  telephone  lines.  In 
receiving  sets  the  audio-frequency  am- 
plifier magnifies  such  currents.  The 
term  "audio-frequency"  is  used  to  desig- 
nate electric  currents  of  less  than  10,000 
cycles  or  alternations  per  second,  be- 
cause such  currents  can  be  used  to  set 
up  sound  waves  affecting  the  auditory 
nerves. 

An  electric  copy  of  the  sound  waves 
having  been  produced  by  the  micro- 
phone and  its  associated  equipment,  it 
is  next  amplified  by  vacuum  tube  am- 
plifiers until  it  is  a  very  powerful  audio- 
frequency current.  If  broadcasting  is 
done  with  the  aid  of  telephone  lines  from 
a  remote  control  point,  from  four  to  ten 
stages  of  amplification  may  be  used. 
All  these  amplifiers  use  batteries  in 
order  to  assure  an  absolutely  quiet 
reproduction,  free  of  hums  and  clicks. 
This  current  is  further  amplified  by  the 
modulator  tubes  of  the  transmitter  until 
it  is  of  the  same  order  of  magnitude  as 
the  radio  frequency  carrier  current 
itself.  All  of  this  manifold  amplification 
must  be  carried  out  without  the  intro- 
duction of  distortion  or  extraneous  noise 
if  good  quality  of  reproduction  is  to 
result. 

Another  process  is  required,  however, 
before  these  currents  can  be  radiated 
into  the  ether.  While  audio-frequency 
currents  pass  successfully  through  wire 
telephone  circuits,  they  do  not  set  up 
electro-magnetic  waves  when  used  to 
charge  an  antenna  system.  The  property 
of  setting  up  electro-magnetic  waves  in 
the  ether  is  possessed  by  radio  frequency 
currents.  In  broadcasting,  very  high 
frequencies  are  used.  The  wavelength 
of  a  station  is  determined  by  the  fre- 
(Turri  to  page  52) 


*     Tested  and  Approved  by  RADIO  AGE     ¥ 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


51 


*AMSCO 

ALLOCATING 
CON DENSER 


(Straight  line  frequency) 

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Spreads  the  Stations 
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combination  of  electrical  engineering  and  mechanical 
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will  be  found  to  represent  10  broadcasting  kilocycles 
accurately  over  the  entire  scale — "  a  station  for  every  de- 
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of  other  S.L.F.  Condensers — it  conserves  space!  Scien- 
tific low-loss  construction.  Rigidity  with  light  weight. 

Made  in  three  capacities  —  Single  or  Siamese.  Ask  your  dealer,  or 
write  for  details   of  the   entire  AMSCO  Line  of  engineered  radio  parts. 

AMSCO  PRODUCTS,  INC.  Dept.  p. 

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52 


RADIO  AGE  for  October,  1925 

TRUE  TONE  QUALITY 


Vo 


'OLUME  was  formerly  the  goal  of  radio  engineers.  The  blare  of  dis- 
cordant trumpets  succeeded  the  tinkling  of  the  harp.  The  goal  had  been 
reached. 

But  true  tone  quality  is  the  star  we  now  are  shooting  at.  This  explains  the 
phenomenal  growth  of  the  demand  for  resistance  coupled  amplification. 
The  end  of  the  era  of  distortion  is  in  sight. 

Daven  engineers  have  pioneered  in  resistance  coupled  amplification. 
Daven  Resistors  and  Mountings,  Ballasts,  Amplifier  Kits  and  Super- 
Amplifiers  are  standard  everywhere. 

The  Daven  Super- Amplifier  is  the  aristocrat  of  amplifiers.  Absolutely  no 
distortion.  A  revelation  to  music  lovers.  It  is  sold  by  dealers  everywhere, 
complete,  ready  to  connect  with  tuner  and  batteries,  for  $15.00. 

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MORE  volume  of  true  tone  quality  is  the  latest  achievement  of  Daven  engineers. 
The  new  Daven  Tube  Type  MTJ-20  increases  the  amplification  of  the  Daven  Super 
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each. 

The  Daven  Power  Tube  Type  MU-6  for  the  last,  or  output  stage — $5.00  each. 
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THE    BIG     LITTLE     THINGS     OF     RADIO 


The  Magazine  of  the  Hour 

Where  Does  the  Power  Come 
From? 

(Continued  from  page  50) 
quency  of  the  currents  used  to  charge 
or  discharge  the  antenna.  Thus,  for  in- 
stance, a  wavelength  of  300  meters  is  set 
up  by  a  current  of  a  million  frequency 
and  492  meters  by  610,000  frequency. 

Various  methods  for  generating  these 
high  frequency  currents  have  long  been 
known  to  radio  art.  But  how  to  com- 
bine the  radiating  properties  of  radio 
frequency  with  the  audio-frequency  com- 
ponent necessary  to  the  transmission  of 
speech  and  music  long  baffled  the 
scientists  who  devoted  themselves  to 
the  problem.  The  first  use  of  radio 
frequency  currents  in  communication 
was  for  dot  and  dash  telegraphy.  By 
means  of  the  transmitting  key,  the  gen- 
erator of  high  frequency  currents  is 
connected  and  disconnected  from  the 
antenna  system  in  accordance  with  the 
telegraph  code. 

How  It  Started 
'  I  ''HE  first  attempts  at  radio  telephony 
-*-  consisted  of  using  a  variable  resistance 
to  vary  the  amount  of  radio  frequency 
current  in  the  antenna,  according  to  the 
sound  waves  to  be  sent  out.  Thus,  the 
carrying  qualities  of  the  radio  frequency 
current  are  utilized,  while  the  distinc- 
tive communication  possibilities  of  speech 
are  retained. 

In  these  early  radio  telephone  trans- 
mitters, microphones  were  used  in  series 
with  the  antenna  system  to  accomplish 
this  variation  of  the  radio  frequency  or 
"carrier"  current.  But  microphones 
are  practical  only  for  controlling  small 
currents.  When  the  radio  frequency 
heavy  currents  necessary  for  long  dis- 
tance transmission  are  passed  through 
them,  they  fail  to  carry  the  load. 

The  process  of  combining  radio  and 
audio-frequencies  is  called  modulation. 
A  practical  method  obviating  the  neces- 
sity for  heavy  microphone  currents  suit- 
able for  high  power  transmission  was 
developed  by  R.  A.  Heising.  It  depends 
for  its  operation  upon  varying  the  plate 
potential  of  a  vacuum  tube  transmitter 
rather  than  changing  the  resistance  of 
the  antenna  system  as  radio  frequency 
currents  are  applied  to  it.  With  the 
Heising  system,  the  audio-frequency 
microphone  currents  are  magnified  by 
successive  stages  of  amplification  until 
they  are  of  the  same  order  of  magnitude 
as  the  radio  frequency  carrier.  These 
amplified  microphone  currents  are  used 
to  add  or  subtract  from  the  plate  poten- 
tial supply  of  the  radio  frequency  oscil- 
lator tubes.  Thus,  the  carrying  qualities 
of  radio  frequency  currents  are  combined 
with  the  communication  properties  of 
audio-frequency  currents  to  set  up 
electro-magnetic  waves  in  the  ether. 

The  work  of  the  receiving  set  is  just 
the  reverse  of  that  of  the  transmitter. 
In  an  antenna  system  within  the  in- 
fluence of  electro-magnetic  waves  from 
a  distant  transmitter,  there  is  set  up 
within  it  a  combination  of  radio  and 
audio-frequency  currents  identical  in 
frequency  and  characteristics  with  those 
of  the  distant  transmitter  which  set  up 
the  electro-magnetic  waves. 
{Turn  to  page  55) 


¥     Tested  and  Approved  by  RADIO   AGE     * 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


53 


An  IMPROVED  Slide  Wire 
Bridge 

(Continued  from  page  18) 
frequency  currents.  This  buzzer  will 
then  be  mounted  on  one  of  the  end  pieces 
of  the  box,  with  the  adjusting  screw 
protruding  through  to  the  outside  of  the 
box.  The  buzzer  will  have  terminals 
(Bl)  and  (B2). 

An  "ON" — "OFF"  battery  switch  will 
be  mounted  on  the  same  end  piece  of  the 
box  as  the  buzzer  and  will  have  terminals 
(SI)  and  (S2). 

Two  binding  posts  will  be  mounted 
on  the  end  piece  opposite  the  one  on 
which  the  above  equipment  is  mounted 
and  will  be  designated  (R)  and  (Rl). 
Two  binding  posts  will  also  be  mounted 
on  each  side  of  the  box.  Those  on  one 
side  will  be  designated  (X)  and  (XI). 
and  those  on  the  other  side  (Y)  and  (Yl) 
The  instrument  will  then  be  ready  to  be 
wired. 

Stranded,  rubber-covered  or  braided, 
cotton  covered  wire  should  be  used  to 
wire  the  instrument,  as  this  wire  is  not 
as  liable  to  come  loose  at  the  terminals 
or  soldered  connections  as  solid  or  bus 
wire.  It  is  also  necessary  that  some 
flexible  wire  be  used  for  certain  leads  to 
make  it  possible  to  remove  the  cover, 
or  panel,  when  it  is  necessary  to  replace 
the  flash-light  battery  (E).  This  battery 
should  not  have  to  be  replaced  for  at 
least  five  or  six  months  as  the  current 
drain  from  the  average  high  frequency 
buzzer  is  only  about  thirty  milli-amperes. 
The  following  wiring  chart  will  simplify 
the  connecting  up  of  the  instrument  and 
offers  a  good  means  to  check  the  wiring 
for  errors. 

WIRING  CHART 
RUN  ONE  LEAD  FROM       TO  TERMINAL 

Switch  terminal  (SI) 
Switch  terminal  (S2) 
Buzzer  terminal  (Bl) 
Battery  terminal  (E2) 
Coil  terminal  (13) 
Pot.  terminal  (PI) 
Coil  terminal  (14) 
Pot.  terminal  (P2) 
Pot.  terminal  (R2) 
Binding  post  (Yl) 
Binding  post  (Rl) 


Battery  terminal  (El) 
Buzzer  terminal  (B2) 
Coil  terminal  (12) 
Coil  terminal  (II) 
Pot.  terminal  (PI) 
Binding  post  (X) 
Pot.  terminal  (P2) 
Binding  post  (Y) 
Binding  post  (R) 
Binding  post  (Rl) 
Binding  post  (XI) 


A  piece  of  white  bristol  board,  for  the 
scale,  will  be  cut  into  a  disk  five  inches 
in  diameter.  A  hole  will  be  cut  in  the 
center  to  pass  over  the  knob  or  sleeve 
of  the  metal  dial  (S).  The  scale  should 
be  marked  on  this  disk  so  that  when 
the  dial  is  rotated  as  far  to  the  right  as 
possible,  the  dial  marker  will  be  directly 
over  the  "O"  point  on  the  scale  and 
when  it  is  turned  as  far  to  the  left  as 
possible,  the  marker  will  be  over  the 
"100"  point  on  the  scale.  A  partial 
scale  is  shown  in  figure  five,  to  exact 
size,  and  may  be  used  as  a  guide  in 
spacing  the  sections  if  desired.  A  scale 
smaller  than  five  inches  in  diameter  may 
be  used  if  necessary,  but  the  divisions 
will  fall  closer  together  than  on  the  larger 
one  and  it  will  be  more  difficult  to  get  a 
reading  as  accurate  as  with  the  larger  one. 

When  the  scale  has  been  fastened  to 
the  dial  (S)  and  the  battery  (E)  has  been 
placed  in  the  clips  (details,  figure  three), 
the  panel  will  be  made  fast  to  the  box 
and  the  set  is  ready  for  operation. 
(Turn  to  page  64) 


Watch  For  Announcement  of 

The  Radio  Age 

Model  Receiver 


In  the  November  issue  of  Radio  Age  you 
will  find  the  announcement  of  a  fully 
illustrated  article  showing  how  to  build  a 
radio  receiver  at  home.  It  will  be  a  five- 
tube  receiver,  designed  and  thoroughly 
tested  by  the  technical  experts  of  the 
RADIO  AGE  staff. 

The  circuit  will  bear  the  endorsement  of 
this  magazine  and  it  will  carry  our  own 
name. 

Co-operating  with  the  RADIO  AGE 
staff  in  designing  this  model  set  will  be 
the  engineers  of  leading  manufacturers 
of  standard  parts.  All  apparatus  used 
in  this  particular  receiver  will  be  specified 
under  the  trade  names. 


You  will  not  want   to   miss   this   best 
technical  radio  feature  of  1925-1926. 

See  the  November  issue  for  further  details. 


theJOWHCMER 

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Shows  how  to  get —  greater  distance, 

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Hner  tone 

Science  has  discovered  a  new  principle  in 
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development  that  is  bringing  unheard  of  re- 
sults. This  principle  is  founded  upon  a  new 
kind  of  coil — the  Erla  Balloon  Circloid.  It 
brings  4  distinct  improvements.  These  are 
explained  in  a  fascinating  book  just  pub- 
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RADIO'S    LUCKIEST 
DEVIL 

— In  November  Radio  Age 


54 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Flour 


ODE.U  S-  P  -2 


cNgw  and  Improved 

Freshman 


Five  Tube  Tuned 

Radio  Frequency 
Receiving    Set. 

For  dry  or  storage 
^,  battery  tubes 


Built  in  a  massive  cabinet 
of  striking  lines  and  pro- 
portions, with  sloping 
panel.  Accurate  and  care- 
ful construction  assures 
distance  possibilities,  sim- 
plicity of  operation  and 
tone  qualities  unfound  in 
sets  costing  many  times 
as  much. 

Phaa. Freshman  fb.lnc. 

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32-50  5.  Clinton  St., 


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1 


Standard  Radio  Receivers 

Sometime  ago  RADIO  AGE  inaugurated  a  new  department  called  "Know 
Before  You  Buy,"  to  serve  as  a  guide  to  the  prospective  radio  purchaser  in 
deciding  on  the  receiver  best  suited  to  his  individual  needs.  Fans  throughout 
the  country  have  shown  a  keen  interest  in  this  new  feature,  and  accordingly  it 
is  being  made  a  feature  of  all  numbers  of  RAD  1 0  AGE.  Readers  are  invited 
to  write  us  concerning  the  sets  in  which  they  are  interested,  and  manufacturers 
also  are  asked  to  send  us  material  describing  their  sets. 

Day-Fan  Five-Tube  Receiver 


.•RHEOSTAT  (K) 


CONOENSER  NO.  » 


FILAMENT        BATTERY 
CONTROL         SWITCH 
RHEOSTATS 


RADIO  FREQUENCY 
TRANSFORMERS 


Inside  view  of  five-tube  set 


IN  all  Day-Fan  sets  the  makers  use  the 
Duoplex  circuit,  which  is  a  develop- 
ment of  their  own  laboratory.  The  four 
tube  Duoplex  has  two  stages  of  tuned 
radio  frequency,  detector  and  two  stages 
of  audio  frequency  amplification.  The 
five  tube  Duoplex  has  three  stages  of 
radio  frequency  amplification  (two  being 
tuned  and  one  untuned),  detector,  and 
two  stages  of  audio  frequency  amplifica- 
tion. The  four  tube  circuit  has  five 
tube  range,  volume,  and  selectivity. 
The  five  tube  circuit  has  six  tube  range, 
volume,  and  selectivity.  Under  favor- 
able conditions,  Day-Fan  receivers  will 
bring  in  any  station  anywhere  in  the 
United  States,  Canada  or  the  West 
Indies  when  the  desired  station  is  broad- 
casting at  1000  watts  or  more. 

The  single  dial  control  on  the  five  tube 
sets  is  a  distinctive  Day-Fan  achieve- 
ment. It  has  all  the  advantages  of  the 
three  dial  with  the  simplicity  of  single 
dial  control.  It  can  be  operated  in  the 
dark,  and  beautiful  music  is  often  most 
greatly  appreciated  in  a  dimly  lighted 
room.  The  children  can  tune  in  just  as 
well  as  the  grown-ups,  and  yet  none  of 
the  advantages  of  the  three-dial  control 
have  been  sacrificed  to  attain  this  extreme 
simplicity. 

The  exceptional  tone  quality  of  the 
Day-Fan  receivers  is  due  to  very  care- 
ful research  and  costly  design  and  manu- 
facture. We  all  know  that  there  are  many 
sounds  above  and  below  the  range  of  or- 
dinary music  and  to  which  our  ears  do 
not  respond,  but  perhaps  you  had  not 
realized  that  the  radio  receivers  of  the  past 
entirely  excluded  the  pedal  notes  of  the 
organ   and   the   deep   bass   notes   of  the 


orchestra.  Such  tones  are  of  vital  im- 
portance in  bringing  out  the  grandeur 
of  orchestral  and  organ  music  and  with- 
out them  such  music  loses  a  great  deal. 
By  the  design  and  construction  of  Day- 
Fan  audio  transformers  all  of  these  low 
tones  are  faithfully  reproduced  with  the 
result  that  the  music  coming  from  the 
Day-Fan  is  of  great  beauty  and  fullness 
of  tone. 

[  tWhat  to  Expect  From  a  Radio  Set 

The  radio  set  today  is  a  highly  efficient 
and  truly  remarkable  instrument.  When 
properly  operated  it  will  give  excellent 
results  and  will  bring  into  the  home — 
entertainment,  instruction  and  news  in  a 
manner  that  was  undreamed  of  four 
years  ago.  There  are,  however,  certain 
conditions  under  which  no  radio  set  can 
give  satisfaction.  These  conditions  may 
be  divided  into  two  classes;  those  which 
can  be  corrected  and  those  over  which 
the  operator  has  no  control.  Some  of 
the  conditions  which  the  owner  can 
regulate  for  himself  are: 

1.  Your  receiver  should  be  made  by  a 
reputable  manufacturer  who  has  the 
organization  and  facilities  for  correctly 
designing  and  manufacturing  so  highly 
sensitive   an   instrument 

2.  You  can  select  accessories  of  a 
grade  at  least  equal  to  that  of  your  re- 
ceiver, as  no  receiving  set  can  be  better 
than  its  accessories. 

3.  You  can  erect  an  efficient  antenna 
and  make  a  satisfactory  ground  connec- 
tion, as  these  are  extremely  important 
for   satisfactory   operation. 


*     Ttttei  end  Approved  bf  RADIO  AG!     * 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


55 


(Continued  from  page  52) 

Often  two  stages  of  radio  frequency 
amplification  are  used  to  bring  up  the 
magnitude  of  this  tiny  current  set  up  in 
an  antenna  system. 

The  power  to  operate  your  receiver, 
therefore,  does  not  come  from  the  trans- 
mitting station;  the  energy  received  from 
the  transmitting  station  is  simply  used 
to  control  the  output  of  the  "B"  battery 
through  the  valve  action  of  the  grid  of 
ths,  vacuum  tube.  This  valve  or  am- 
plification is  somewhat  similar  to  the 
valve  effect  of  a  water  faucet  controlling 
a  stream  of  water.  A  child  can  turn 
on  and  off  a  faucet  controlling  200 
pounds  of  pressure.  In  the  same  way, 
the  grid  of  a  vacuum  tube  controls  a 
much  larger  current  flowing  through  the 
plate  circuit,  suppied  by  the  "B" 
battery. 

If  the  radio  frequency  amplifier  has 
increased  the  combination  of  radio  and 
audio-frequency  currents  to  a  sufficient 
magnitude,  the  detector  tube  then 
smooths  out  the  radio  frequency  com- 
ponent, so  that  the  effect  of  the  audio- 
frequency component  only  remains.  Thus 
the  process  of  modulation  is  reversed. 
The  audio-frequency  amplifier  then  per- 
forms its  function  of  increasing  the 
magnitude  of  this  current.  Finally, 
it  is  converted  into  sound  waves  by  the 
telephone  or  loud  speaker,  reversing  the 
action  of  the  microphone  circuit  of  the 
transmitter. 

The  vacuum  tube  plays  an  important 
part  in  each  of  these  many  steps.  Any 
undesired  variation  in  plate  potential 
introduced  at  any  point  at  once  affects 
the  fidelity  of  ultimate  reproduction. 
For  this  reason,  "B"  batteries  are  used 
in  preference  to  any  other  source  of 
plate  potential.  The  "B"  battery  relies 
upon  electro-chemical  action,  contributed 
by  billions  of  atoms  within  each  cell 
and  its  output  is,  therefore,  continuous 
and  unvarying.  A  generator  depends 
for  its  action  upon  the  sum  of  impulses 
set  up  in  a  number  of  inductances  re- 
volving in  a  magnetic  field.  Some  gen- 
erators have  as  many  as  760  coils  re- 
volving at  a  thousand  RMP,  but  even 
such  a  generator  has  variations  in  its 
output,  which,  when  applied  to  the  plate 
of  the  vacuum  tube,  produce  a  hum  in 
the  receiving  set. 


New  "B"  Power  Unit 
Produced 

The  Radio  Units,  Inc.,  of  Maywood, 
111.,  announce  the  "B"  RADIOPOWER 
UNIT.  It  is  essentially  an  automatic 
"B"  battery  and  not  a  "B"  battery  elimi- 
nator, since  it  consists  of  a  dry  storage 
battery  together  with  a  trickle  charging 
arrangament  built  into  a  handsome 
walnut  cabinet. 

They  are  also  producing  the  PADDLE- 
WHEEL  COIL,  a  new  and  superior 
type  of  inductance  which  was  released  to 
the  trade  late  last  season. 


"Up  in  the  Arctic  with 
the  Short  waves." — By 
Armstrong  Perry,  in  Nov. 
RADIO  AGE. 


* 


There's  a  Real  Thrill 

in  trying  a  New  Hook-Up! 


Bradleyswitch— Perfect 

Battery  Switch 


Bradleystat— Perfect 

Filament  Control 
for  all  Tube* 


Bradleynier—  Perfect 
Vernier  Knob 


Bradleylealt— Perfect  Grid 
Leak  lA  to  10  Megohms 


EVERYONE  in  the  family 
is  eagerly  waiting  to  hear  the 
new  set.  After  hours  and 
hours  of  drilling  and  soldering,  the 
set  is  nearly  ready  for  its  first 
crucial  test. 

Will  it  meet  with  your  expectations  or  will 
it  be  a  disappointment  ?  That  depends  upon 
two  things  —  first  your  workmanship,  and 
second,  the  quality  of  the  parts  used. 

Good  workmanship  is  the  result  of  patience, 
but  good  parts  are  assured  only  by  demand- 
ing well-known,  guaranteed  products,  such 
as  Allen-  Bradley  Perfect  Radio  Devices. 
Allen-Bradley  products  are  known  the 
world  over  for  exceptional  performance  and 
fine  appearance.  They  eliminate  the  hazard 
and  disappointment  that  follows  the  use  of 
inferior  radio  products. 

Ask  your  dealer  for  Allen-Bradley  Perfect 
Radio  Devices  if  you  value  your  time  and 
labor.  They  always  work! 


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g     TfUi  mad  Approved  feg  2ADI0  AGS     * 


56 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


URERS 


The    Story    of    the    Powerola 
Radio 

Powerola  is  electric  radio  without  any 
batteries  or  chemicals  whatever.  It  can 
be  used  universally,  operating  directly 
from  the  standard  A.  C.  or  D.  C.  light- 
ing circuits  in  the  home,  office  or  plaae 
of  business.  By  plugging  into  the  house 
lighting  socket,  the  tubes  in  the  receiver  are 
lit  and  the  set  ready  for  tuning.  It  becomes 
another  electric  necessity  like  an  electric 
iron,  toaster,  or  other   electrical  device. 

For  alternating  current,  two  rectify- 
ing bulbs  (2  ampere),  in  connection  with 
a  transformer,  condensers  and  choke  in 
these  circuits,  enables  the  receiver  to 
obliterate  all  power-line  hums  and  noises, 
and  to  deliver  the  required  voltages  and 
watt  power.  For  direct  current  a  simple 
but  practical  arrangement  is  employed 
in  connection  with  a  choke,  some  con- 
densers and  resistances,  and  with  the 
filaments  of  the  tubes  in  series,  which  also 
smoothes  out  all  generator  hums  and 
noises,  and  produces  the  needed  constants 
and  potentials.  There  are  no  additional 
controls  added  on  the  rectifier  or  set  to 
compensate  a  variation  in  voltage  on  the 
110  volt  supply,  A.  C.  or  D.  C.  Powerola 
is  designed  for  A.  C.  100-115  volts,  40-60 
cycles,  and  for  D.  C.  110-120  volts. 

Five  standard  tubes,  such  as  the  five 
or  six  volt  201A  or  301A,  and  standard 
phones  and  loud  speakers,  are  employed. 

The  Terminal  Electric  Company  es- 
tablished in  1910,  for  the  past  fifteen 
years  has  been  manufacturing  battery- 
eliminating  power  devices.  It  is  an  old 
established,  and  highly  regarded  manu- 
facturing firm.  The  value  and  security 
of  such  an  experienced  precision  manu- 
facturer cannot  be  under-estimated. 
Every  piece  of  material  which  is  of  the 
best  and  every  stage  of  manufacture  is 
thoroughly       tested.  Powerola       has 

strength  and  charm,  is  built  to  last  a 
life  time  and  is  fully  guaranteed. 

Details  of  Daven  Radio  Corpor- 
ation Expansion 

Due  to  increased  business  and  the 
necessity  of  giving  the  best  service  pos- 
sible to  manufacturers,  Daven  distribut- 
ors and  Daven  dealers,  The  Daven  Radio 
Corporation  recently  adjusted  their  orga- 
nization and  made  many  new  and  import- 
ant changes. 

VV.  H.  Frasse,  President,  announces 
the  appointment  of  K.  R.  Moses  as  Sales 
Manager.  Mr.  Moses  was  previously 
Sales  Promotion  Manager  of  Crosley 
Radio  Corporation,  and  Sales  Manager  of 
the  Amberola  Division  of  the  Thomas  A. 
Edison,  Inc.  Mr.  Moses  has  had  twelve 
years  of  phonograph  and  radio  experience, 
consequently  the  problems  of  merchan- 
dising radio  are  nothing  new  to  him. 

W.  A.  Balevre  has  been  appointed 
Advertising  and  Sales  Promotion  Manag- 
er. Mr.  Balevre  has  been  connected 
with  the  Daven  Radio  Corporation  for 
the  past  eighteen  months  and  before  that 
was     with     the     Adams      Mbrgan      Co. 


Burns   Concert   Speaker   Unit 
Now  Ready 

The  American  Electric  Company  of 
Chicago  now  announce  the  marketing  of 
an  attractive  new  Speaker  Unit — the  No. 
120  Concert  model.  This  has  all  the 
excellent  tone  qualities  of  the  No.  100 
Burns  Unit  and  in  addition  has  a  much 
greater  range,  being  particularly  adapted 
to  reach  the  extremes  of  the  musical 
scale. 

With  this  Concert  Unit  it  is  no  longer 
necessary  to  sacrifice  those  high  notes  or 
the  low  bass  ones,  which  have  hitherto 
been  lost  and  which  left  much  to  be  de- 
sired in  the  quality  of  loud  speaker  re- 
production. 

The  exceptional  tone  quality  of  the 
Burns  Speaker  has  already  won  for  it 
thousands  of  enthusiastic  users.  In  the 
Concert  model  a  mellowness  of  tone 
combines  most  effectively  with  the  ex- 
treme sensitiveness  of  the  instrument. 
The  slightest  variations  of  sounds,  the 
voice  with  all  its  fine  shadings  and  the 
various  musical  instruments  with  their 
wide  range  of  pitch  are  reproduced  with 
exquisite  trueness. 

Remarkable  tone  volume  is  secured  yet 
it  is  easily  regulated  to  suit  the  occasion 
and  to  harmonize  with  the  subject  being 
reproduced.  A  convenient  tone  adjuster 
is  placed  on  back  of  mechanism  case. 

The  substantial  size  of  this  new  unit 
and  exactness  of  construction  assures  a 
sturdiness  and  durability  not  otherwise 
obtainable.  Rigid  inspection  is  employ- 
ed throughout  the  course  of  manufactur- 
ing. 

The  Concert  Unit  is  arranged  with  con- 
nectors for  fitting  any  standard  make  of 
phonograph. 

Thomas  Loop  Distributed 
Nationally 

The  W.  I.  Thomas  Company,  fibre 
manufacturers  of  Chicago,  have  announ- 
ced they  have  na- 
tion-wide distribu- 
tion for  their  line  of 
loop  aerials,  known  as 
"Thomas  Selecto 
Loops." 

The  Thomas  loops, 
one  of  which  is  illus- 
trated in  the  accom- 
panying drawing, 
come  in  two  sizes — 
large  and  small.  The 
model  shown  sells  for 
$12.50  and  incorpora- 
tes all  the  latest  de- 
sign in  loop  aerials, 
being  the  result  of 
several  months'  ex- 
periment. 

Mr.  W.  I.  Thomas 
has  just  announced 
that  exclusive  Western  distribution  of 
the  loops  has  been  awarded  the  Radio- 
graph Laboratories,  of  210  E.  Ohio  St., 
Chicago.  Thomas  loops  are  being  na- 
tionally advertised  this  season. 


New  WSBC  Station  Using 
Storage  Batteries 

Making  its  maiden  bow  and  bid  for 
popular  favor  is  the  1,000  Watt  Radio 
Broadcast  Transmitter  sponsored  by 
the  World  Battery  Company  of  Chicago, 
operating  under  Station  Call  Letters 
WSBC  on  210  meters,  and  constructed  by 
the  Engineers  of  that  concern. 

The  World  Battery  Company  Trans- 
mitter, as  the  new  outfit  is  officially  desig- 
nated, is  novel  in  many  respects  and 
unique  in  that  the  power  for  the  opera- 
tion is  supplied  entirely  by  storage  bat- 
teries, made  up  of  identically  the  same 
materials  as  are  used  in  the  standard, 
stock  batteries  supplied  to  radio  users 
for  the  operation  of  receiving  sets.  For 
instance,  the  "B"  or  tube  plate  supply  of 
2,400  volts  is  furnished  by  the  equivalent 
of  over  400  ordinary  receiving  6- Volt  "A" 
batteries  made  up  of  the  same  parts  that 
are  used  in  the  unit  familiar  to  all  radio 
fans.  By  an  ingenious  switch  arrange- 
ment these  can  be  connected  in  straight 
series  to  operate  the  set  or  in  series  paral- 
lel for  charging. 

The  "C"  or  biasing  batteries  as  well 
as  those  used  for  the  microphone  cir- 
cuits are  made  up  of  the  parts  used  in  the 
standard  24  volt  units  such  as  are  used 
for  the  "B"  supply  in  receiving  sets. 

Although  the  battery  installation  is  a 
good  deal  more  expensive  than  is  the 
equivalent  motor  generator  set,  it  is  felt 
that  the  additional  expense  is  more  than 
compensated  for  by  the  clarity  of  trans- 
mission, it  being  well  known  that  the 
smooth  steady  flow  of  power  from  storage 
batteries  insures  a  clearness  that  can 
only  be  approximated  by  the  generator 
system.  Other  exclusive  features  are 
incorporated  in  the  design  and  construc- 
tion of  the  transmitter  proper. 

New  Straight  8  Out  in  Sept. 
Priess  Announces 

Announcement  has  been  made  at  the 
offices  of  William  H.  Priess,  president  of 
the  Priess  Radio  Corporation,  that  the 
company's  new  receiver,  known  as  the 
"Straight  8,"  was  in  production  and 
would  make  its  appearance  before  the 
public  in  September,  which  on  account 
of  the  radio  expositions,  is  popularly 
assumed  to  be  the  seasonal  opening. 

A  good  deal  has  been  heard  about 
this  set,  for  it  has  been  known  all  along 
that  the  makers  were  aiming  to  produce 
a  receiver  of  exceptional  power;  a  distance 
getter  and  volume  producer  unmeasured 
by  previous  standards. 

Uncommon  secrecy  has  been  maintain- 
ed all  during  the  experiments,  which  have 
run  into  many  thousands  over  an  unusual 
length  of  time.  Besides  Mr.  Priess's  per- 
sonal application  and  that  of  his  labora- 
tory staff,  consulting  engineering  talent 
has  been  employed  to  an  unusual  degree. 

No  descriptive  statement  of  the 
"Straight  8"  has  appeared  as  yet,  and 
it  is  understood  that  the  makers  prefer 
to  let  its  performance  talk  for  it. 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


57 


More  Super  Stations  are 
Coming! 

( Continued  from  page  24) 

station  into  direct  current,  which  is  used 
for  plate  supply  on  the  various  trans- 
mitters. The  modulating  equipment 
may  be  connected  with  any  of  the  smaller 
buildings  by  means  of  a  system  of  over- 
head transmission  lines.  Speech  and 
music  to  be  broadcast  are  obtained  from 
the  studio  of  WGY  over  an  aerial  cable 
circuit.  It  is  further  amplified  at  the 
station  before  reaching  the  group  of 
metal  tubes  known  as  modulators.  The 
transmitter  to  be  modulated  obtains  its 
plate  supply  in  common  with  the  modu- 
lator tubes  through  a  group  of  reactors. 

A  dark  room  is  provided  in  the  main 
building  for  developing  oscillograph  films 
recording  modulation.  A  circulating 
pump  having  a  capacity  of  150  gallons 
per  minute  supplies  cooling  water  for  all 
metal'  tubes.  The  water  is  piped  to  all 
of  the  smaller  buildings. 

In  addition  to  the  rectifiers,  a  12,000 
volt  direct  current  generator  is  used  for 
supplying  plate  voltage  for  master 
oscillators  and  other  low  powered  equip- 
ment. Generators  supplying  4,000  volts 
and  2500  volts  are  used  for  plate  supply 
to  the  smaller  tubes.  The  filaments  of 
all  tubes  are  heated  by  direct  current. 
There  are  several  direct  current  gener- 
ators of  300  ampere  capacity  at  33  volts 
and  1000  amperes  capacity  at  this  voltage. 

At  present  there  are  two  transmitters 
located  in  the  main  building — one  is 
operated  at  50  kw.  on  379.5  meters. 
This  transmitter  is  of  the  master  oscil- 
lator —  intermediate  amplifier  —  power 
amplifier  type  using  20  kw.  water  cooled 
tubes  in  the  high  power  stages. 

The  second  transmitter  operating  at 
1560  (2XAH)  meters  has  a  maximum  of 
40  kw.  and  is  of  the  same  general  type 
as  2XAG  except  that  push-pull  ampli- 
fiers are  used  in  the  power  stages. 

The  109  meter  transmitter  is  located 
in  one  of  the  smaller  wooden  buildings. 
Circuits  for  this  equipment  are  the 
master  oscillator  intermediate  ampli- 
fier power  amplifier  type,  in  order  to 
obtain  constancy  of  frequency.  The  high 
voltage  supply  is. carried  from  the  main 
building  to  this  transmitter  by  means  of 
overhead-lines.  Modulation  for  the  109 
meter  transmitter  is  provided  in  Building 
No.  1  from  the  main  bank  of  modulators. 

The  antenna  system  is  supported  by 
three  wooden  poles  each  80  feet  high, 
arranged  in  the  form  of  a  triangle.  This 
type  of  antenna  stucture  has  been  em- 
ployed in  order  to  permit  a  study  of  the 
various  types  of  antennas  which  may  be 
suitable  for  operation  at  this  wavelength. 

In  common  with  all  the  other  low 
wavelength  transmitters,  the  low  voltage 
and  high  current  machine  equipment 
is  located  in  a  separate  building  adjacent 
to  the  transmitter  house  proper.  With 
fairly  long  wavelength  transmitters  the 
machine  equipment  can  be  placed  in  the 
transmitter  house;  with  short  wave- 
length transmitters  it  is  necessary  to 
not  only  spring-suspend  the  tubes  but 
remove  the  motor  generator  sets  to  a 
distant  point  in  order  to  reduce  the 
vibration  to  a  minimum. 


Better  reception  this 
season  than  last ! 


rOULD  you  like  better 
reception  this  fall  and 
winter  than  last?  Better  dis- 
tance? Better  volume?  Better 
tone?  You  will  enjoy  better  re- 
sults in  every  way,  this  season, 
if  you  keep  your  tubes  at  full  effi- 
ciency with  the  Jefferson  Home 
Tube  Rejuvenator. 

All  tubes  deteriorate  rapidly 
with  use.  The  Jefferson  Tube 
Rejuvenator  "brings  them 
back" in  10 minutes!  Useitonce 
a  month — keep  your  tubes  like 
new.  Completely  restores 
paralyzed  or  exhausted  tubes. 
Doubles  and  trebles  tube  life, 
quickly  payingfor  itself  through 
this  great  saving. 

Takes  large  or  small  tubes  — 
types  201-A,  301-A,  UV-199, 
C-299,5-VA.  Attach  to  any  al- 
ternating current  electric  light 
socket  in  your  home.  The  Jef- 
ferson Home  Rejuvenator  for 
tubes  is  as  essential  to  satisfac- 
tory radio  reception  as  acharger 
for  storage  batteries.  Get  one 
now;  start  the  season  with  your 
tubes  inperfectcondition.  Sold 
by  leading  dealers  in  radio  sup- 
plies, and  fully  guaranteed. 


#10  in  Canada 


Jefferson  Electric 

Manufacturing  Co. 

501  S.  Green  St.,        Chicago,  III. 

Makers  of  Jefferson  Radio,  Bell  Ringing  and 
Toy  Transformers;  Jefferson  Spark  Coils  for 
Automobile,  Stationary  and  Marine  Engines; 
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for 
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Radio  Transformers 

Your  radio,  no  matter  how 
costly,  can  be  no  better  than 
its  transformers.  Our  experi- 
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— clear,  pure,  sweet,  natural 
tones  from  your  radio — make 
sure  it  is  equipped  with  Jef- 
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the  better  radio  dealers,  used 
by  leading  set  manufacturers. 


TUBE    REJUVENATOR 

Keeps  radio  tubes  like  new 


*     Tasted  and  Approved  by  RADIO   AGE     * 


58 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


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TUNING^       CONTROL 


PHENIX  RADIO  CORP.,  116-FEast25  St.,  N.Y.C. 


With  the  Manufacturers 


(Continued  from  page  56) 


The  one  serious  problem  in  radio  recep- 
tion has  always  been  the  battery  prob- 
lem. Manufacturers  have  spent  many 
sleepless  nights  trying  to  develop  a  fool- 
proof device  that  would  eliminate  either 
the  "A"  or  "B"  battery,  or  possibly  both. 
In  most  cases  these  devices  were  very 
costly  and  had  their  weak  points. 

In  solving  this  problem,  a  new  and 
untraversed  channel  of  thought  was  con- 
ceived by  A.  L.  Levin  of  the  Lestein  Cor- 
poration of  America,  New  York  City. 
His  idea  was  to  make  the  tube  itself, 
which  is  necessarily  of  special  construc- 
tion, do  the  major  part  of  the  work  and 
use  a  simple  adaptor,  which  is  not  the 
ordinary  battery  eliminator,  which  will 
function  to  eliminate  the  necessity  of  re- 
wiring a  set  that  has  been  in  service. 


Their  new  tube  operates  equally  well 
on  any  110  volt  supply  having  either 
direct  or  alternating  characteristic.  It 
contains  two  electron  emitting  surfaces, 
which  result  in  a  far  richer  electronic 
emission  per  unit  of  surface  than  is 
obtained  in  the  present  storage  battery 
type  tube,  which  in  turn  tends  to  pre- 
vent the  possibility  of  overloading. 

The  filament,  which  is  lit  directly  from 
the  110  volt  supply,  also  functions  as  a 
heater  for  an  additional  element,  which 
when  heated,  emits  electrons.  The  elec- 
tronic emission  from  the  filament  is 
used  for  rectifying  purposes  and  the  emis- 
sion from  the  new  element,  surrounding 
it  in  the  form  of  a  circle,  which  measures 
1-8  inch  in  diameter,  functions  in  the 
same  manner  as  the  filament  emission 
from  the  present  day  tubes. 

The  general  size  and  appearance  of 
this  new  tube  is  the  same  as  that  of  the 
present  day  storage  battery  201A  type 
tube.  The  standard  four  prong  base  is 
used,  and  the  internal  elements  are  so 
wired  to  these  prongs  that  the  filament, 
plate,  and  grid  leads  will  connect  to  any 
standard  base  socket  used  with  the  pres- 
ent   day   tubes. 

Radio  fans  can  control  the  workings  of 
their  sets  without  any  technical  knowl- 
edge or  annoyance.  The  adaptor  can 
be  easily  connected  with  all  radio  receiv- 
ing sets  on  the  market  todav.  The  tube, 
will  be  known  as  the  "LESTRON" 
tube  and  can  be  used  in  any  radio  set 
and  where  ever  the  present  radio  tubes 
are  used  and  will  eliminate  all  batteries. 


New  Eveready  "Layerbilt"  a 
Big  Advance 

The  new  flat  cell  "B"  battery  recently 
announced  by  the  National  Carbon  Com- 
pany, makers  of  Eveready  batteries, 
utilizes  the  new  principle  of  patented 
battery  construction  by  substitution  of 
flat  cells  for  cylindrical  cells.  There  is 
about  30%  more  active  electricity-pro- 
ducing material  than  in  the  Heavy  Duty 


battery  No.  770  of  identical  external 
dimensions.  It  retails  for  $5.50  and  is 
guaranteed  to  give  considerably  longer 
life  than  any  other  "B"  battery  of  the 
same  dimensions.  More  than  30,000  of 
these  batteries  have  already  been  tested 
by  users  in  actual  service  and  from  30 
to  52%  longer  life  has  been  obtained 
under  the  same  conditions  of  service  as 
compared  with  any  cylindrical  cell 
batteries  of  the  same  external  dimensions. 


A  Quiet  Battery  Charger 

The  Interstate  Electric  Company  of 
St.  Louis,  Mo.,  has  augmented  its  line 
of  Battery  Chargers  by  designing  a 
Twin  Bulb  Handy  Battery  Charger. 

The  manufacturer  states  that  this 
machine  is  absolutely  quiet  in  operation 
and  is  also  a  fast  rate  charger.  Either 
one  or  two  of  the  bulbs  in  the  machine 
may  be  used.  When  both  bulbs  are 
used  it  is  possible  to  charge  six  volt 
batteries  at  four  to  five  amperes. 

The  Twin  Bulb  Charger  charges 
efficiently  both  "A"  and  "B"  batteries 
and  will  charge  "B"  batteries  24,  48, 
72,  96,  120,  voltage  in  series.  The  Twin 
Bulb  Charger  employs  the  advanced 
"PUSH  PULL"  principle  using  both 
halves  of  the  A.  C.  wave. 

No  moving  parts  are  used  in  this 
machine  or  liquids  or  vibrators  of  any 
kind.  Naturally  adjustments,  corrosion 
and  sticking  trouble  are  eliminated. 
This  charger  is  fully  enclosed  in  a  beauti- 
ful mahogany  finished  metal  case,  with  a 
handle  and   accurate  ammeter. 

The  retail  price  will  be  $17.00  without 
the  bulbs,  making  it  a  reasonably  priced 
charger. 


Armstrong  Perry,  Brainard  Foote,  Frank  Pearne,  H.  F. 
Hopkins,  John  B.  Rathbun,  Roscoe  Bundy — "The  Cream  of 
Radio  Experts" — All  in  November  RADIO  AGE  ! 


*     T—Ud  and  Approved  by  RADIO  AGE     # 


RADIO.AGE/or  October,  1925 


The  Magazine  of  the  Hour 


59 


'■ '  1 

Ittlllltlrrr 

mi 

*5 

"Tilt 

"Ht 

~^m  rrfp* 

"ft: 

—+: 

.00025 
Straight  Line  Wave  Length 


*ff1T7T-T-TTT-*fff  ff'T" 


.00035 
Flat  Wave  Length  Curve 


Consider  what  a  Condenser 
is  for!  Your  choice  will  be 

We  BARRETT  &  PADEN 

Micrometer  Condenser       & 

{for  any  Type  of  Set) 

YOU  USE  a  variable  condenser  to  obtain  certain  capac- 
ity values  in  the  tuning  circuit.  One  measure  of  a  con- 
denser's efficiency  is  the  precision  with  which  it  enables  you 
to  obtain  the  various  wanted  capacities. 

The  Barrett  &  Paden  Micrometer  Condenser  will  give  you 
a  wider  variation  of  capacity  values  and  far  more  accurate 
adjustment  than  any  other  condenser  in  the  world,  for  the 
same  reason  that  a  mechanic's  micrometer  enables  him  to  make 
infinitely  closer  measurements  than  he  could  with  a  rule. 

Qet  These  Results! 

You  will  hear  stations  which  have  never  had  a  place  on  your  dials  be- 
fore; tuning  will  be  easier  and  selectivity  much  better;  signals  will  be 
louder  because  of  the  extremely  low  loss  characteristic  of  this  condenser. 

Install  Barrett  &  Paden  Micrometer  Control  Variable  Condensers  in 
your  set  now.  You  will  be  amazed  at  the  immediate  tremendous  differ- 
ence they  will  make  in  your  set's  performance.  At  your  dealers  or  direct. 


.00025 — straight  line  wave  length 
.00035 — flat  wave  length  curve 
.0005   — straight  line  capacity 


00  including 
dial 


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:,;  g.-  X^ggSP^i^  g. 


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^r  prepared  by  K  title 


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J 


The  Best  Plug  at  a  Better  Price 

The  Pacent  Autoplug 

Now  60c 


THIS  plug  is  entirely  shock-proof,  for  the  entire  length  of  the  cord 
tips  is  encased  by  the  plug  shell  and  no  metal  parts  are  exposed. 
The  shell  is  made  of  genuine  Bakelite.  No  screws  are  used  in  its  as- 
sembly, and  there  is  nothing  to  work  loose  or  cause  trouble. 
Pacent  parts  are  used  by  40  leading  manufacturers  in  the  construction 
of  their  sets.  It  will  profit  "you  to  get  in  touch  with  us. 
See  your  dealer,  and  write  us  for  the  new  Pacent  Catalog  of  Complete 
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*     Tested  and  Approved  by  RADIO  AGE     * 


60 


RADICfAGE/or  October,  1925 


Quam  Condensers 

With  The  Pyrex  End  Plate 

make  tuning 
a  real  Joy 


* 


Furnished  in  straight  line  frequency  and  straight  line  wavelength  design.  The 
straight  line  frequency  condensets  spread  all  stations  evenly  around  the  dial  accord- 
ing to  frequency.  The  plates  are  so  fashioned  that  no  excess  panel  space  is  required. 
The  two  to  one  helical  gears  assure  sharpest  tuning  and  smoothness  of  operation 
not  possible  where  the  dial  is  mounted  directly  on  the  rotor  shaft. 
1 — "  leakage  paths  on  a  genuine  Pyret  end  plate  make  the  QUAM  the  lowest  loss 
condenser  in  the  world.  Sturdily  built,  with  brass  frame  and  plate  soldered  in  place 
assure  minimum  resistance  losses.  Beautifully  designed  and  finished,  it  is  truly  the 
condenser  that  will  last  a  lifetime  and  constantly  give  satisfaction. 


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Chicago 


$2.50  A  YEAR 


Gentlemen:  Please  enter  my  subscription  for  RADIO  AGE.  the  Magazine  of  the  Hour,  for  one 
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Send  cash,  money  order  or  draft. 


The  Magazine  of  the  Hour 

A  Distortionless  Audio 
Amplifier 

(Continued  from  page  16) 

Thus,  the  sockets  may  be  fastened  to  a 
panel  or  they  may  be  screwed  to  a  base- 
board with  small  wood  supports  between 
them  and  the  base,  just  sufficient  to 
hold  the  resistance  clips  above  the  base- 
board. 

Figure  1  shows  a  top  view  of  this  same 
unit  attached  to  a  7x10  bakelite  panel, 
which  also  carries  the  rheostat  controlling 
all  tubes,  and  the  input  and  output 
jacks.  These  jacks  cut  out  the  entire 
amplifier,  or  cut  it  all  in,  as  desired. 
The  volume  may  be  very  nicely  con- 
trolled by  the  rheostat,  which  also 
serves  to  turn  the  unit  off  when  not  in  use. 

Parts  Required 

HPHE  material  necessary  to  build  the 
J-  unit  costs  about  $18.00,  and  is  listed 
below.  All  parts  should  be  of  first  class 
manufacture,  particularly  the  resistances 
and  condensers.  Standard  panel  sockets 
should  be  used,  which  will  accommodate 
either  UV201A  or  WD12  tubes.  UV199 
would  have  to  be  used  with  adapters, 
but  this  will  not  impair  the  efficiency  of 
the  set,  though  it  does  make  for  an 
excellent  mechanical  arrangement.  De- 
Forest  D  V3  dry  cell  tubes  will  fit  standard 
sockets,  or  the  new  UV199,  soon  to  be 
out  with  standard  bases,  will  fit  the 
sockets  recommended. 

1  6! 2  ohm  rheostat 
1  101  jack,  1  spring 
1  102a  jack,  2  SPRINGS 

5  Insulated  top  binding  posts 
3  Panel-mounting  sockets 

6  .0075  condensers 
6  grid  leak  mounts 

3  xV  MEG.  LEAKS 

1  J4  MEG.  LEAK 

2  34  MEG.  LEAKS 

1 7  X  2  Yi  X   H"  BAKELITE  PANEL 
17  X  10  X   yi"  BAKELITE  PANEL 

Lugs,  bus-bar,  No.  &  Flathead  screws  and 
nuts,  solder  and  spaghetti. 

The  panels  should  be  prepared  by  drill- 
ing them  in  accordance  with  the  drawing, 
Fig.  2,  using  the  drill  sizes  shown,  and 
countersinking  holes  where  this  operation 
is  indicated.  The  smaller  panel  has 
some  holes  countersunk  on  one  side,  and 
some  countersunk  on  the  other.  This  is 
because  the  heads  of  the  screws  fastening 
the  sockets  come  under  the  leak  clips 
and  condensers,  and  the  screw  heads 
fastening  these  parts  come  under  the 
sockets.  Three-quarter-inch  flat-head 
brass  No.  jj  machine  screws  should 
be  used.  These  will  be  so  long  as  to 
interfere  with  the  leaks  where  they  are 
used  to  hold  the  clips,  when  they  may  be 
broken  off  with  a  pair  of  pliers;  or  shorter 
screws  may  be  used  to  hold  the  leak  clips. 

The  assembly  is  started  by  putting 
through  the  sub-panel  the  six  screws 
used  to  hold  the  sockets,  but  not  fastening 
the  sockets  to  them  with  nuts.  Then, 
with  these  six  screws  hanging  loose  in 
their  holes,  the  four  condensers  and  six 
leak  clips  are  screwed  on  to  the  sub-panel 
by  putting  fiat-head  screws  through  it 
from  the  other  side.  After  this  has 
been  done,  the  three  sockets  may  be 
placed  in  position,  and  nuts  tightened 
up  on  the  six  screws  used  for  holding 
them.     A  reference  to  Figure  3  will  show 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


61 


how  the  parts  are  put  in  place  on  the 
sub-panel,  and  just  how  lugs  are  put  on 
the  leak  clips  and  condensers.  Lugs  are 
shown  on  some  condensers,  and  if  solder- 
ing paste  is  to  be  used,  the  wiring  should 
be  run  to  these  lugs,  and  not  to  the 
condensers.  If  no  paste  is  used  in  solder- 
ing to  the  condensers,  the  wires  may  be 
soldered  direct  to  the  small  rivets  used 
for  holding  the  brass  plates  of  the  con- 
densers together. 

The  five  binding  posts  are  put  on  the 
sub-panel  as  shown  in  Fig.  3,  with  lugs 
under  the  screw  heads  as  indicated. 

The  wiring  may  be  started,  using  a 
well  tinned  iron,  rosin  core  solder,  and 
a  small  quantity  of  non-corrosive  paste. 
Each  lug  should  be  tinned  separately  and 
each  wire  should  be  bent  and  cut  for 
its  position  before  any  attempt  is  made 
to  solder  it  in  position.  It  should  be 
tinned  first  at  points  where  it  will  be 
soldered  to  a  lug. 

Operation 

ONCE  the  amplifier  has  been  comple- 
ted, the  proper  batteries  need  only 
be  connected  to  it,  the  tubes  inserted, 
and  the  unit  connected  to  a  set  and  loud 
speaker,  and  it  will  work.  However, 
before  connecting  it  for  operation  there 
are  one  or  two  tests  to  make.  First,  the 
A  battery  should  be  connected  to  its 
posts,  the  tubes  inserted,  and  the  rheostat 
turned  on.  The  tubes  will  light[_if  all 
connections  are  correct.  If  they  do, 
disconnect  the  A+  wire,  and  connect  it 
to  the  b+  post.  The  tubes  should  not 
light,  and  if  they  do,  there  is  an  error  in 
the  wiring  which  must  be  corrected. 
Assuming  they  light  only  when  the  A 
battery  is  connected  to  its  proper  posts, 
a  90-  or  135-volt  B  battery  should  be 
connected  to  the  posts  marked  for  it  in 
the  diagram.  Two  or  three  45-volt 
batteries  will  give  this  voltage  nicely. 

If  the  same  batteries  are  to  be  used  on 
the  amplifier  that  operate  the  receiver, 
these  will  generally  consist  of  the  neces- 
sary A  battery  together  with  90  volts  of 
B  battery.  If  this  is  the  case,  the  simplest 
way  to  connect  the  amplifier  is  to  run 
two  wires  from  its  A+  and  A—  posts, 
to  the  A+  and  A—  posts  of  the  receiver. 
Then,  if  no  more  B  battery  than  is  used 
on  the  receiver  is  to  be  used  with  the 
amplifier,  the  B+  post  of  the  amplifier 
need  only  be  connected  to  the  B  +  post 
of  the  receiver.  If  additional  voltage  is 
to  be  used  on  the  amplifier — say  135 
volts  where  90  volts  is  used  on  the  re- 
ceiver— an  extra  45  volt  battery  should 
be  connected  with  its  plus  lead  to  the 
plus  B  post  of  the  amplifier  and  its  minus 
lead  to  the  plus  B  post  of  the  receiver. 

In  no  case  is  it  necessary  to  make  a 
connection  from  the  amplifier  to  the 
B  — ,  as  the  B  —  is  always  connected  to 
the  A  battery  at  the  receiver.  This 
return  may  be  connected  in  the  case  of 
the  receiver  to  either  the  plus  or  minus 
side  of  the  A  battery,  but  in  any  case 
it  will  be  fed  through  on  the  common 
A  battery  wiring  to  the  amplifier.  It 
is  of  very  little  importance  whether  this 
B  return  is  connected  to  the  plus  or 
minus  lead  of  the  A  battery,  so  whatever 
wiring  is  used  for  the  receiver  will  do 
for  the  amplifier. 


Partners  for  Power 


The  Tungar  is  a  G-E 
product  developed  in  the 
great  Research  Labora- 
tories of  General  Electric. 

Thenew  Tungar  charges 
2,  4,  6  volt  "A"  batteries; 
24to96voIt"B"batteries, 
in  series:  and  auto  bat- 
teries, too.  No  extra  at- 
tachments needed. 

Two  ampere  size  (East 
of  the  Rockies)   .  $18.00 

|        60  cycles— 110  volts 


If  you  want  distance  and  clear  tone  from  your 
radio  set,  your  storage  battery  must  have  its 
partner— the  Tungar  Battery  Charger. 

Two  clips  and  a  plug  to  connect  to  the  house 
current.  That's  all  there  is  to  it.  Or  you  can 
make  permanent  connection  and  just  throw  a 
switch. 

The  Tungar  charges  while  you  sleep — it  makes 
no  disturbing  noise — keeps  your  batteries  at  cop 
notch.  For  power  there  is  nothing  like  a  good 
storage  battery — with  a  Tungar  to  keep  it  good. 


* 


Tungar— a  registered  trademark— is  found  only 
on  the  genuine.    Look  for  it  on  the  name  plate. 


Merchandise  Division 
General  Electric  Company,  Bridgeport  Conn. 


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62 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


Every  Radio  Fan 

should  have  this 

hook 


I.C.S. 

RADIO 

HANDBOOK 


100,000  SOLD 
514  PAGES 


Compiled  by 
HARRY  F.  DART,  E.E. 

Formerly  with  the 
Weitern  Electric 
Co..  and  U.  S. 
Army  Instructor  of 
Radio.  Tech- 
nically edited  by 
F.  H.  DOANE. 


BE  A  RADIO  expert— it's  easy  for  the  100,000 
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rules.     Many  other  features. 


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Chemistry    Handbook,    348    pages    -     - 

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Traffic  Handbook,  3S6  pages  -     -     -     - 

Building  Trades  Handbook,  409  pagea  - 

_  Machine    Shop    Handbook,    335    pages    - 

J  Salesman's    Handbook,    352    pages    -     - 

"Advertising   Handbook,    445   pages   -     - 

_  Bookkeeper's  Handbook,   302  pages  -     - 

3  Civil   Engineer's   Handbook,    411    pages 

n  Steam   Engineer's   Handbook,    298    pages 


Address.. 


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_J 


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Have  You  Bought  Your 
ANNUAL? 


How  the  New  KYW  is 
Getting  Power 

(  Continued  from  page  30) 
determines  and  holds  the  wavelength 
constant  and  which  is  impedance  coupled 
to  the  antenna.  A  development  of  the 
Hartley  oscillating  circuit  is  used  and  the 
modulators  work  on  the  Heising  prin- 
ciple. 

The  impedance  or  choke  coupling 
between  the  tank  and  the  antenna  cir- 
cuits is  considerable  of  an  advantage  to 
the  radio  listeners,  because  it  secures 
extremely  loose  coupling  of  the  trans- 
mitter and  the  choke  eliminate  prac- 
tically all  energy  in  the  harmonics  which 
have  been  a  source  of  trouble  in  the  past. 

The  antenna  is  composed  of  two  3J^ 
inch  horizontal  cages,  140  feet  long  and 
supported  by  two  125  feet  steel  towers. 
The  down  leads  are  two  similar  cages 
and  connect  the  antenna  to  an  open  cir- 
cuit tuning  inductance  near  the  base 
of  the  south  tower.  The  counterpoise 
is  a  10  wire  fan,  radiating  from  the  south 
tower  to  points  equally  distant,  entirely 
around  the  hotel  roof.  More  than  1% 
miles  of  hard  drawn  copper  wire  went  into 
the  construction  of  the  antenna  system. 

50  Pairs  of  Wires! 

TWO  cables  each  containing  fifty 
pairs  of  telephone  wires  connect  the 
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studios  and  the  numerous  outside  points 
from  which  programs  are  broadcast. 
The  cables  terminate  on  a  large  telephone 
test  board,  through  which  telephone 
lines  may  be  balanced  and  equalized  to 
pass  all  the  complex  voice  and  musical 
frequencies  from  50  to  6000  cycles. 

Provision  is  made  on  this  board  for 
setting  up  phantom  and  simplex  circuits 
over  any  line  so  that  studio  equipment 
may  be  remote  controlled  and  adjusted 
from  the  station.  The  telephone  test 
board  is  connected  through  plug  and 
jack  arrangement  to  a  smaller  board  on 
the  operating  desk,  only  the  circuits  to 
be  used  that  day  coming  in  on  the 
operator's  board.  By  means  of  this 
small  switchboard  he  is  able  to  change 
from  one  studio  to  another,  talk  to  any 
studio  or  connect  back  the  output  of  one 
studio  into  another  so  the  waiting  artists 
there  may  hear  the  program. 

A  small,  well  arranged,  control  desk 
starts,  stops,  and  adjusts  the  entire 
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A  bank  of  amplifiers  or  repeators 
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RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


63 


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64 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


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How  to  Make  a  New  Slide 
Wire  Bridge 

(Continued  from  page  53) 

The  operation  of  the  slide  wire  bridge 
is  simple^  As  previously  explained,  all 
that  is  required  will  be  to  connect  an 
ordinary  set  of  head-phones  to  the  bind- 
ing posts  (R)  and  (Rl)  and  turn  the 
switch  (SW)  to  the  "ON"  position. 
The  coils  or  condensers  to  be  matched 
or  balanced  will  be  connected  to  the 
binding  posts  (X)  and  (XI)  and  (Y) 
and  (Yl),  as  directed  in  the  following 
examples. 

Balancing  Transformer 

'T'O  BALANCE  the  coils  of  a  trans- 
-*-  former  or  other  type  of  inductive 
coil,  connect  the  inside  terminal  of  one 
of  the  coils  to  binding  post  (X)  and  the 
outside  terminal  of  the  same  coil  to 
binding  post  (XI).  The  same  procedure 
will  be  taken  with  the  other  coil  except 
the  terminals  will  be  connected  to  bind- 
ing posts  (Y)  and  (Yl).  The  switch 
(SW)  will  be  turned  to  its  "ON"  position 
and  the  dial  rotated  to  the  right  or  left 
until  no  tone  is  heard  in  the  head  phones. 
If  the  silent  point  falls  on  50,  the  im- 
pedance of  the  coils  is  the  same;  if  the 
silent  period  shows  a  dial  reading  of  40, 
the  coil  connected  to  the  binding  posts 
(X)  and  (XI)  has  a  greater  impedance 
than  the  coil  connected  across  binding 
posts  (Y)  and  (Yl)  and  it  will  be  neces- 
sary to  add  turns  of  wire  to  coil  (Y) 
until  the  dial  reading  shows  50  at  the 
silent  period. 

If  the  dial  reading  should  fall  on  60, 
the  coil  connected  across  binding  posts 
(Y)  and  (Yl)  will  have  an  impedance 
greater  than  coil  (X)  and  it  will  be  neces- 
sary to  remove  turns  of  wire  from  coil 
(Y)  to  match  it  with  coil  (X).  When  it 
is  desired  to  match  a  coil  or  winding  with 
a  coil  or  winding  that  is  not  to  be  changed 
it  would  be  well  to  get  into  the  habit  of 
considering  the  coil  connected  to  bind- 
ing posts  (Y)  and  (Yl)  as  the  master 
and  always  work  coil  (X)  as  the  variable 
or  coil  to  be  balanced. 

To  balance  more  than  two  coils  or 
windings,  the  first  two  will  be  balanced 
as  above  and  coil  (X)  will  be  removed; 
the  third  coil  will  then  be  connected  to 
the  binding  posts  (X)  and  (Xl)  and  be 
balanced  in  the  same  manner. 

Transformers  or  coils  so  matched  or 
balanced  will  have  characteristics  similar 
enough  to  fall  within  a  few  meters  of  one 
another  and  should  work  well  together. 

Balancing    Or    Measuring    Capacity 

To  measure  the  capacity  between 
windings  of  a  transformer,  the  same  pro- 
cedure will  be  followed  as  for  measuring 
impedance,  except  that  the  inside  ter- 
minal of  the  primary  coil  will  be  con- 
nected to  binding  post  (X)  or  (Y)  and 
the  inside  terminal  of  the  secondary 
coil  connected  to  binding  post  (Xl) 
or  (Yl).  The  dial  will  be  rotated  until 
the  silent  period  is  located  and  a  balance 
obtained  as  was  done  for  impedance; 
if  the  reading  should  fall  on  50,  the  coils 
are  matched,  if  it  falls  on  40,  the  capacity 
(Turn  to  page  65) 


0  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


65 


Better  Results 
From  3  Tubes 
Than  From  5 


Instead  of  passing  the  incoming 
signal  once  through  each  of  5 
tubes,  Crosley  design,  in  the 
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volume. 

Even  the  technically  uninitiated 
can  see  the  advantages:  sim- 
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fewer  dials  to  adjust;  sharper 
accuracy  in  selecting  stations; 
greater  clarity;  greater  volume, 
greater  ease  in  logging  stations. 

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between  coils  of  the  transformer  (Y) 
is  greater  than  that  of  coil  (X)  and  the 
windings  will  have  to  be  placed  closer 
together  or  the  dielectric  material  be- 
tween the  coils  will  have  to  be  changed 
until  the  reading  shows  50. 

To  measure  the  capacity  of  a  con- 
denser, a  condenser  whose  capacity  is 
known  will  be  connected  across  binding 
posts  (X)  and  (XI)  and  the  condenser 
to  be  measured  will  be  connected  across 
binding  posts  (Y)  and  (Yl)  the  same 
operation  will  take  place  as  on  the  other 
measurements  except  in  determining 
the  capacity.  This  will  be  done  by 
reading  the  dial  and  working  the  follow- 
ing formula — assuming  the  capacity 
of  the  master  condenser  to  be  .5  mf. 
dial  reading  25,  then  the  capacity  of 
condenser  (X)  will  be  greater  than  that 
of  (Y)  as  explained  in  "Thompsons" 
method.  To  charge  two  condensers  of 
unequal  capacity  with  equal  quantities 
of  electricity  requires  a  higher  E.  M.  F. 
applied  at  the  terminals  of  the  smaller 
condenser,  that  is,  the  E.  M.  F.  applied 
at  the  terminals  must  be  inversely  pro- 
portional to  the  capacities. 

From  this,  it  will  be  seen  that  a  greater 
amount  of  electricity  is  being  applied  to 
the  condenser  (X)  than  to  condenser 
(Y);  therefore  condenser  (Y)  is  three 
times  as  large  as  (X)  from  reading  the 
dial  as  (Y)  =f  x  (X)  or  1.5  mf.  For  a 
graphic  explaination  of  this  formula 
see  figure  two. 

Measuring   Impedance   of   Inductive 
Coils 

To  measure  the  impedance  of  a  coil, 
a  coil  whose  impedance  is  known,  will 
be  connected  across  the  binding  posts 
(Y)  and  (Yl)  and  the  coil  to  be  measured 
will  be  connected  across  binding  posts 
(X)  and  (XI).  The  same  operation  will 
take  place  as  on  the  other  measurements 
except  in  determining  the  impedance; 
this  will  be  done  by  reading  the  dial  and 
working  the  following  formula — assum- 
ing the  impedance  of  the  master  coil  to 
be  one  henry,  dial  reading  60,  then  the 
impedance  of  the  coil  (X)  will  be  |x(X) 
or,  substituting  the  values  of  the  scale 
readings  a  =  60.  From  this,  b  would  be 
40,  as  in  the  schematic  diagram,  figure 
two;  b  =  100  — a.  The  formula  would 
then  be  jjxl  henry  =Y  or  .66  Henry. 

Many  other  forms  of  measurements 
may  be  made  on  this  instrument  as  well 
as  those  mentioned  above.  The  same 
formulas  will  be  used,  slightly  modified, 
remembering  that  the  dial  reading  will 
take  the  place  of  "a"  and  that  "b"  will 
always  be  the  result  of  subtracting  the 
amount  of  a  from  the  entire  scale  of  the 
bridge,  which  is  100.  From  this,  it 
will  be  found  that  if  "a"  =25  which 
would  be  the  dial  reading,  then  "b" 
will  be  75  or  the  sum  difference  between 
the  dial  reading  of  25  and  the  scale  of 
100. 

To  accurately  measure  resistance  to 
direct  current,  it  would  be  necessary 
to  connect  a  galvanometer  across  the 
terminals  (R)  and  (Rl)  and  to  connect 
the  small  battery  across  terminals  (13; 
and  (14),  with  the  switch  (SW)  in  the 
(OFF)    position. 

#     Tested  and  Approved  by  RADIO   AGE 


SUPER^^* 

pXrts 


S-L-F! 


Real  S-L-F  Condensers  at 
last!  Silver-Marshall  have 
met  the  demand  for  an  all- 
round  s tr ai g ht- lin e- 
frequency  condenser  by  pro- 
ducing an  instrument  that 
meets  the  requirements  of 
lowest  losses,  small  size, 
attractive  appearance,  and 
— most  important — actual 
S-L-F  tuning  efficiency.  All 
types  supplied  with  pulley 
collars  so  that  from  one  to 
five  condensers  may  be  con- 
trolled by  a  single  knob, 
without  separate  verniers. 
The  S-M  Condensers  are 
entirely  silver-plated — -a 
feature  that  reduces  losses 
lower  than  laboratory  stan- 
dards. 

No.  310      .0005 $6.00 

No.  311      .00035.... 5.75 

No.  312      .00025 5.50 

S-M 


The  famous  S-M  210  and 
211  Intermediate  transfor- 
mers, used  in  the  receivers 
developed  by  McMurdo 
Silver  and  in  several  other 
well  known  designs,  pro- 
vide the  highest  amplifica- 
tion of  any  transformers  on 
the  market.  Each  trans- 
former is  laboratory-mea- 
sured and  supplied  with  in- 
dividual curves — your  guar- 
antee of  uniformity  I  The 
new  bakelite  case  is  es- 
pecially attractive  and  effi- 
cient. Filter  furnished  with 
measured  tuning  condenser. 
Transformers  supplied  in 
sets  of  two  210's  and  one 
211. 

Each $8.00 

Send  4c  in  stamps  for  circulars 
describing  the  latest  S-M  develop- 
ments, including  the  new  cushion- 
ed sockets  for  UX  and  UV  tubes 
and  the  interchangeable  coils  for 
all-wave  receivers.  Magazine  re- 
prints describing  the  super-auto- 
dune  and  the  all-wave  super  are 
freel 

Silver  -  Marshall,  Inc. 

114  S.  Wabash  Ave. 
Chicago,  Illinois 


66 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA  Westinghouse  Electric  &  Mfg.  Co East  Pittsburgh,  Pa. 

KDLR  Radio  Electric  Co Devils  Lake,  N.  D. 

K.DPM  Westinghouse  Electric  &  Mfg.  Co Cleveland.  Ohio 

KDYL  Newhouse  Hotel Salt  Lake  City,  Utah 

KD2B  Frank  E.  Siefert Bakersfield,  Calif. 

KDZI  Electric  Supply  Co Wenatchee,  Wash. 

KFAB  Nebraska  Buick  Auto  Co..  13th  &  Que  Sts Lincoln,  Nebr. 

KFAD  Mc Arthur   Bros.   Mercantile  Co Phoenix,  Ariz. 

K.FAE  State     College   of    Washington Pullman,  Wash. 

KFAF  Western    Radio   Corporation Denver,   Colo. 

KFAJ  University  of  Colorado Boulder,  Colo. 

KFAN  University  of  Idaho Moscow,  Idaho 

KFAU  Boise  High  School Boise.  Idaho 

KFAW  The  Radio  Den  (W.  B.  Ashford) Santa  Ana,  Calif. 

KFBB  F.  A.  Buttrey  &  Co HavTe,  Mont. 

KFBC  W.  K.  Azbill San  Diego,  Calif. 

KFBG  First   Presbyterian   Church Tacoma,   Wash. 

KFBK.  Kim  ball -Upson  Co Sacramento.  Calif. 

KFBL  Leese     Bros Everett.  Wash. 

KFBS  School  District  No.  One Trinidad,   Colorado 

KFCB  Nielson  Radio  Supply  Co Phoenix.  Ariz. 

KFCC  The  First  Congregational  Church Helena.  Mont. 

KFCF  Frank  A.  Moore Walla  Walla,  Wash. 

KFCZ  Omaha  Central  High  School Omaha,  Nebr. 

KFDD  St.  Michaels  Cathedral Boise,  Idaho 

KFDH  University  of  Arizona Tucson,   Ariz. 

KFDJ  Oregon    Agricultural    College Corvallis,    Oreg. 

KFDM  Magnolia  Petroleum   Co Beaumont,  Texas 

KFDX  First    Baptist    Church Shreveport.    La. 

KFDY  South  Dakota  State  College Brookings,  S.  Dak. 

KFDZ  Harry   O.   Iverson Minneapolis,    Minn. 

KFEC  Meier   &   Frank   Co Portland,  Oreg. 

KFEK  A ugsbury  Seminary Minneapolis.  Minn. 

KFEL  Winner  Radio  Corp Denver,  Colo. 

KFEQ  J.  L.  Scrogfiin Oak.  Nebr. 

KFEY  Bunker  Hill  &  S""ivan  Mining  and  Concentrating  Co Kellogg,  Idaho 

KFFP  First  Baptist   Church Moberly,   Mo. 

KFFV  Gracelar,d    College Lamoni,    Iowa 

KFGB  Heidbreder  Radio  Supply  Co Utica,  Neb. 

KFGC  Louisiana  State  University Baton  Rouge.  La. 

KFGD  Chickasha  Radio  &  Electric  Co Chickasha,  Okla. 

KFGH  Leland  Stanford  University Stanford  University,  Calif. 

KFGS  Crary    Hardware     Co. Boone,     Iowa 

KFHA  Western  State  College  of  Colorado Gunnison,  Colo. 

KFHH  Ambrose  A.  McCue Neah  Bay,  Wash. 

KFHL  Penn    College Oskaloosa,    Iowa 

KFI  E.  C.  Anthony,   Inc Los  Angeles.   Calif. 

KFIF  Benson  Polytechnic  Institute Portland,  Oreg. 

KFIO  North    Central  High   School Spokane,  Wash. 

KFIO  First  Methodist   Church Yakima,   Wash. 

KFIU  Alaska  Electric  Light  &  Power  Co Juneau,   Alaska 

KFIZ  Daily  Commonwealth Fond  du  Lac,  Wis. 

KFJB  Marshall   Electrical    Co Marshalltown.    Iowa 

KFJC  R.  B.  Fegan  (Episcopal  Church) Junction  City,  Kansas 

KFJF"  National  Radio  Manufacturing  Co Oklahoma  City,   Okla. 

KFJI  Liberty  Theatre     (E.    E.    Marsh) Astoria.  Oreg. 

KFJL  Hardsacg    Manufacturing    Co Ottumwa,    Iowa 

KFJM  University  of  North   Dakota Grand  Forks.  N.   Dak. 

KFJR  Ashley  C.  Dixon  &  Son Stevensville,  Mont. 

KFJX  Iowa  State  Teacher's  College Cedar  Falls,  Iowa 

KFJY  Tunwall  Radio  Co Fort  Dodge.  Iowa 

KFJZ  W.  E.  Branch Fort  Worth,  Texas 

KFKA  Colorado  State  Teachers  College Greeley.  Colo. 

KFKQ  Conway  Radio  Laboratories  (Ben  H.  Woodruff) Conway.  Aik. 

KFKU  The   University   of   Kansas Lawrence.   Kans. 

KFKX  Westinghouse  Electric  &  Manufacturing  Co Hastings,  Nebr. 

KFLD  Paul    E.    Greenlaw Franklinton,    La. 

KFLP  Everett  M.  Foster Cedar  Rapids,  la. 

KFLR  University  of  New  Mexico Albuquerque,  New  Mexico 

KFLU  Rio  Grande  Radio  Supply  House San  Benito.  Texas 

KFLV  Rev.  A.  T.  Frykman Rockford,  111. 

KFLX  George  Roy  Clough Galveston,  Texas 

KFLZ  Atlantic  Automobile  Co Atlantic.   la. 

KFMB  Christian    Churches Little    Rock,    Ark. 

KFMQ  University  of  Arkansas Fayetteville.  Ark. 

KFMR  Morningside   College Sioux  City,   Iowa 

KFMW  M.    G.    Sateren Houghton,    Mich. 

KFMX  Carleton     College Northfield.    Minn. 

KFNF  Henry   Field    Seed    Co Shenandoah.    Iowa 

K  FNG  Wooten's  Radio  Shop Coldwater,  Miss. 

KFNV  L.  A.  Drake  Battery  and  Radio  Supply  Shop Santa  Rosa.  Calif. 

KFOA  Rhodes    Department    Store Seattle.    Wash. 

KFOL  Leslie  M.  Schafbush Marengo    Iowa 

KFON  Echophone  Radio  Shop Long  Beach,  Calif. 

KFOO  Latter  Day  Saints  University Salt  Lake  City.  Utah 

KFOP  Rohrer    Elec.    Co Marshfield,    Ore. 

KFOR  David  City  Tire  &  Electric  Co David  City.  Nebraska 

KFOT  College  Hill  Radio  Club Wichita,  Kansas 

KFOX  Board  of  Education,  Technical  High  School Omaha,   Nebraska 

KFOY  Beacon  Radio  Sen-ice St.  Paul,   Minn. 

KFPG  Garretson  and  Dennis Los  Angeles    Calif. 

KFPL  C.  C.  Baxter Dublin,  Texas 

KFPM  The   New   Furniture   Co Greenville,   Texas 

KFPR  L03  Angeles  County  Forestry  Dept Los  Angeles,  Calif. 

KFPT  Cape  &  Johnson Salt  Lake  City.  Utah 

KFPW  St.  Johns  M.  E.  Church Carterville    Mo. 

KFPY  Symons    Investment    Co Spokane      Wash. 

KFQA  Tho    Principis. St.   Louis.   Mo. 

KFQB  The  Searchlight  Publishing  Co Fort  Worth,  Texas 

KFQC  Kidd  Brothers  Radio  Shop Taft,  Calif. 

KFQH  Radio    Service    Co Burlingame,    Calif. 

KFQP  G.  S.  Carson.  Jr Iowa  City.  la. 

KFQT  Texas  National  Guard Dennison   Texas 

KFQU  W.  Riker Holy  City,  Calif. 

KFQW  C.    F.    Knierim North    Bend.    Wash. 

KFQZ  Taft     Products     Co Hollywood,     Calif. 

KFRC  City  of  Paris  Dry  Goods  Co San  Francisco.  Calif. 

KFRU  Etherical    Radio   Co Bristow.   Okla. 

KFRW  United  Churches  of  Olytnpia Olympia,  Wash. 

KFRX  J.    Gordon    Klemgard Pullman,   Wash. 

KFRZ  The     Electric     Shop ' Harrington,     Neb. 

KFSG  Angelus     Temple Los     Angeles.     Calif. 

KFSY  The    Van    Blaricon    Co Helena.Mont. 

KFUJ  Hopper  Plumbing  and  Heiting  Co Breckenridge,  Minn. 

KFUL  Thomas  Goggan  &  Bros.  Music  Co Galveston.  Texas 

KFUM  W.   D.   Pyle Colorado  Springs,  Colo. 

KFUO  Concordia   Seminary St.   Louis,    Mo. 

KFUP  Fitzsimmons     Ge  neral     Hospital Denver,     Colo. 

KFUQ  Julius   Brunton   and   Sons   Co San   Francisco,   Calif. 

KFUR  H.  W.  Peery  and  C.  Redfield Ogden,  Utah 

KFUS  Louis     L.     Sherman Oakland,     Calif. 

KFUT  University  of  Utah Salt  Lake  City,  Utah 

KFUU  Colburn    Radio    Labs San    Leandro,    Calif. 

KFUZ  Y.   M.   C.  A Virginia     Minn. 

KFVD  McWhinnie  Electric  Co San  Pedro.  Calif. 

KFVE  Film  Corporation  of  America St.  Louis,  Mo. 

KFVF  Clarence  B.Juneau Hollywood.  Calif. 

KFVG  First    M.    E.    Church Independence,    Kansas 

KFVH  Whan  Radio  Shop   (Herbert  Whan) Manhattan.  Kansas 

KFVI  Headquarters  Troop.  56th  Calvary Houston,  Texas 

KFVN  Carl  E.  Bagley Welcome.  Minn. 

KFVO  F.   M.   Henry Kirksville.   Mo. 

KFVR  Moonlight  Ranch Route  6,  Denver.  Colo. 

KFVS  Cape  Girardeau  Battery  Station Cape   Girardeau,  Mo. 

KFVY  Radio  Supply  Co Albuquerque.  N.  M. 

KFVZ  Glad  Tidings  Tabernacle '. San  Francisco.  Calif. 


309 

KFWA 

231 

KFWB 

270 

KFWC 

250 

KFWV 

240 

WGBU 

360 

KFXB 

341 

KFWD 

273 

KFWF 

348 

KFWH 

278 

KFWI 

360 

KFWM 

230 

KFWO 

271 

KFWP 

280 

KFWU 

360 

KFXC 

278 

KFXD 

250 

KFXE 

283 

KFXF 

224 

KGB 

238 

KGO 

238 

KGU 

248 

KGW 

256 

KGY 

258 

KHJ 

252 

KHQ 

368 

KJR 

254 

KJS 

315 

KLDS 

360 

KLS 

360 

KLX 

231 

KLZ 

KM  A.. 

261 

KMJ 

254 

KMO 

268 

KNX 

233 

KOA 

260 

KOB 

280 

KOIL 

224 

KOP 

254 

KPO 

248 

KPPC 

273 

KPRC 

226 

KQP 

252 

KQV 

261 

KQW 

240 

KRE 

468 

KSAC 

248 

KSD 

252 

KSL 

242 

KTAB 

226 

KTCL 

273 

KTHS 

248 

KTW 

219 

KUO 

252 

KUOM 

252 

KUPR 

242 

KWG 

280 

KWKC 

258 

KWWG 

280 

KYO 

246 

KYW 

254 

KZM 

273 

WAAB 

250 

WAAC 

275 

WAAD 

288 

WAAF 

234 

WAAM 

256 

WAAW 

254 

WABA 

236 

WABB 

229 

WABC 

240 

WABI 

273 

WABL 

254 

WABO 

299 

WABQ 

261 

WABR 

266 

WABW 

336 

WABX 

266 

WABY 

254 

WABZ 

234 

WADC 

454 

WAFD 

234 

WAHG 

234 

WAPI 

261 

WAMD 

240 

WBAA 

226 

WBAC 

231 

WBAH 

248 

WBAK 

226 

WBAO 

238 

WBAP 

242 

WBAV 

242 

WBAX 

231 

WBAY 

286 

WBBG 

268 

WBBL 

283 

WBBM 

264 

WBBN 

221 

WBBP 

258 

WBBR 

231 

WBBS 

284 

WBBU 

252 

WBBX 

253 

WBBY 

248 

WBCN 

240 

WBDC 

268 

WBES 

394 

WBGA 

220 

WBOQ 

217 

WBR 

222 

WBRC 

272 

WBRE 

261 

WBS 

242 

WBT 

258 

WBZ 

242 

WBZ4 

549 

WCAD 

234 

WCAE 

234 

WCAH 

224 

WCAJ 

233 

WCAL 

271 

WCAO 

231 

WCAP 

244 

WCAR 

202 

WCAS 

245 

WCAT 

208 

WCAU 

236 

WCAX 

218 

WCAZ 

248 

WCBA 

227 

WCBC 

226 

WCBD 

246 

WCBE 

224 

WCBF 

250 

WCBG 

234 

WCBH 

Browning  Bros.  Co Ogden,  Utah 

Warner     Bros Hollywood,      Calif. 

L.  E.  Wall Upland,  Calif. 

Wilbur  Jerman 385   58th   St.   S.,   Portland,  Ore. 

Florida  Cities  Finance  Co Fulford    By-The-Sea,  Florida 

Bertram  O.  Heller Big    Bear    Lake,    Calif. 

Arkansas  Light  &  Power  Co Arkadelphia,  Arkansas 

St.  Louis  Truth  Center St.  Louis,  Mo. 

F.  Wellington  Morse,  Jr Chico,  Calif. 

Radio  Entertainments.  Inc South   San   Francisco.  Calif. 

Oakland  Educational  Society Oakland,  Calif. 

Lawrence  Mott Avalon,  Calif. 

Rio  Grande  Radio  Supply  House Brownsville,  Texas 

Louisiana  College Pineville,      La. 

Santa  Maria  Valley  Railroad  Co Santa     Maria.      Calif. 

L.  H.  Strong Logan,    Utah 

Electrical  Research  &  Mfg.  Co Waterloo,   Iowa     236 

Pikes  Peak  Broadcasting  Co Colorado     Springs,     Colo.     2S0 

Tacoma  Daily  Ledger Tacoma,  Wash. 

General  Electric  Co Oakland,  Calif. 

Marion   A.    Mulrony Honolulu,    Hawaii,    Waikiki   Beach 

Portland   Morning  Oregonian Portland,  Oreg. 

St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy,  Wash. 

Times-Mirror  Co Los  Angeles,  Calif. 

Louis  Wasmer Seattle,  Wash. 

Northwest  Radio  Service  Co Seattle.   Wash. 

Bible  Institute  of  Los  Angeles,  Inc Los  Angeles,  Calif. 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints,  Independence,  Mo. 

Warner  Brothers    Radio   Supplies   Co Oakland,   Calif. 

Tribune    Publishing   Co Oakland,    Calif. 

Reynolds  Radio  Co Denver,  Colo. 


212 
278 
203 
266 
214 
254 
220 
224 
211 
214 
238 
210 
205 


252 
361 
370 
491 

253 
405 
273 
384 
293 
441 
242 
508 
283 


San  Joaquin  Light  &  Power  Corp Fresno,  Calif.  243 

Love  Electric  Co Tacoma,  Wash.  250 

Los  Angeles  Evening  Express Los  Angeles,  Calif.  337 

General   Electric   Co Denver,    Colo.  323 

New  Mexico  College  of  Agriculture  &  Mechanic  Arts,  State  College,  N.  Mex.  348 

Monarch  Manufacturing  Co Council  Bluffs,  Iowa  278 

Detroit  Police  Department Detroit,  Mich.  286 

Hale    Bros San    Francisco,    Calif.  428 

Pasadena    Presbyterian    Church Pasadena,  Calif.  229 

Houston  Post-Dispatch Houston,  Texas  270 

Apple  City.  Radio  Club Hood  River,  Oregon  270 

Doubleday-Hill     Electric     Co Pittsburgh,     Pa.  270 

Charls    D.    Herrold San  Jose,   Calif.  226 

V.  C.  Battery  &  Electric  Co Berkeley.  Calif.  275 

Kansas  State  Agricultural   College Manhattan,   Kans.  341 

Post  Dispatch  (Pulitzer  Pub.  Co.) St.  Louis,  Mo.  545 

Radio  Service  Corp.  of  Utah * Salt  Lake  City.  Utah  299 

Tenth    Ave.  Baptist   Church Oakland,  Cal.  216 

American  Radio  Telephone  Co. ,  Inc Seattle.  Wash.  306 

New  Arlington  Hotel  Co Hot  Springe,  Ark.  375 

First  Presbyterian  Church Seattle,  Wash.  455 

Examiner    Printing    Co San    Francisco,    Calif.  246 

State  University  of  Montana Missoula,   Montana  244 

Union  Pacific  Railroad  Co Omaha,  Neb.  270 

Portable  Wireless  Telephone  Co Stockton,  Calif.  248 

Wilson    Duncan    Studios Kansas    City,    Mo.  236 

City    of    Brownsville Brownsville,    Texas  278 

Electric  Shop Honolulu,  Hawaii  270 

Westinghouse  Electric  &  Mfg.  Co Chicago.  111.  535 

Preston    D.    Allen Oakland.    Calif.  242 

Valdemar  Jensen New    Orleans,    La.  263 

Tulane    University New    Orleans,   La.  275 

Ohio  Mechanics  Institute Cincinnati.  Ohio  248 

Chicago   Daily  Drovers   Journal Chicago,   111.  286 

I.    R.    Nelson   Co Newark,    N.   J.  263 

Omaha  Grain  Exchange Omaha,  Nebr.  285 

Lake  Forest  University Lake  Forest,  HI.  227 

Harrisburg    Sporting    Goods    Co Harrisburg,    Pa.  266 

Asheville  Battery  Co.,  Inc Asheville,  N.  C.  254 

Bangor  Railway  <fe  Electric  Co Bangor,  Me.  240 

Connecticut    Agricultural    College Sorra,    Conn.  283 

Lake  Avenue   Baptist  Church Rochester,  N.  Y.  283 

Haverford   College.   Radio  Club Haverford,   Pa.  261 

Scott  High  School,  N.  W.  B.  Foley Toledo,  Ohio  270 

College  of  Wooster Wooster,  Ohio  234 

Henry  B.  Joy Mt.  Clemens,  Mich.  270 

John    Magaldi,    Jr Philadelphia,    Pa.  242 

Coliseum  Place  Baptist  Church New  Orleans,  La.  263 

Allen  T.  Simmons  (Allen  Theatre) Akron,  Ohio  258 

Albert  B.  Parfet  Co Port  Huron.  Mich.  233 

A.  H.  Grebe  &  Co Richmond  Hill.  N.  Y.  315 

Alabama  Polytechnic  Institute Auburn, Ala.  248 

Hubbard  &  Co Minneapolis,  Minn.  244 

Purdue  University W  .  Lafayette,  Ind.  283 

Clemso     Agric.  College Clemson  College,  S.  C.  331 

The  Dayton  Co Minneapolis,  Minn.  417 

Pennsylvania    State    Police Harrisburg,    Pa.  275 

James  Millikan  University Decatur,     HI.  360 

Wortham-Carter  Publishing  Co.  (Star  Telegram) Fort  Worth,  Texas  476 

Erner    &    Hopkins    Co Columbus,    Ohio  292 

John  H.  Stenger.  Jr Wilkes-Barre,   Pa.  254 

Western  Electric  Co New  York,  N.  Y.  492 

Irving    Vermilya Mattapoisett,     Mass.  248 

Grace    Covenant    Presbyterian     Church Richmond,    Va.  253 

Atlass    Investment    Co Chicago,    111.  226 

Blake,  A.  B Wilmington,   N.   C.  275 

Petoskey    High    School Petoskey,    Mich.  246 

Peoples  Pulpit  Asso Rossville,  N.  Y.  273 

First  Baptist  Church New  Orleans,  La.  252 

Jenks    Motor   Sales    Co Monmouth.    III.  224 

Ruffner    Junior    High    School Norfolk,    Va.  222 

Washington    Light    Infantry    Co.    "B"    118th    Inf Charleston.    S.    C.  268 

Foster     &     McDoland Chicago,     111.  266 

Baxter  Laundry  Co Grand   Rapids.   Mich.  256 

Bliss   Electrical   School Takoma    Park.    Md.  222 

Jones  Elec.  &  Radio  Mfg.  Co Baltimore,  Md.  254 

A.  H.  Grebe   &  Co..   Inc Richmond  Hill,   N.  Y.  236 

Pennsylvania   State   Police Butler,   Pa.  286 

Bell   Radio   Corporation Birmingham.    Ala.  248 

Baltimore  Radio  Exchange Wilkes-Barre,  Pa.  231 

D.  W.  May,  Inc Newark.  N.  J.  252 

Southern  Radio  Corp Charlotte.   N.    C.  275 

Westinghouse  Electric  &   Mfg.   Co Springfield,  Mass.  333 

Westinghouse  Electric  &  Mfg.  Co Hotel    Brunswick.    Boston.    Mass.  242 

St.  Lawrence  University Canton.  N.  Y.  280 

Kaufmann  &  Baer  Co.  and  The  Pittsburgh  Press Pittsburgh,  Pa.  461 

Entrekin  Electric  Co Columbus,  Ohio  286 

Nebraska  Wesleyan  University University  Place.  Nebr.  283 

St.  Olaf  College Northfield.   Minn.  336 

Sanders    &    Stayman    Co Baltimore,    Md.  275 

Chesapeake  &  Potomac  Telephone  Co Washington,  D.  C.  468 

Alamo   Radio  Electric   Co San   Antonio,   Texas  263 

W.  H.  Dunwoody  Industrial  Institute Minneapolis,  Minn.  280 

State  College  of  Mines Rapid   City.   S.  Dak.  240 

Durham    &    Co Philadelphia,    Pa.  278 

University    of    Vermont Burlington.    Vt.  250 

Carthage  College ' Carthage.  III.  246 

Charles  W.  Heibachm AUentown,  Pa.  280 

University  of  Michigan Ann  Arbor.  Mich.  280 

Wilbur    C.    Voliva Zion,    HI.  344 

Uhalt  Radio  Co New  Orleans,  La.  263 

Paul    J.    Miller Pittsburgh.    Pa.  236 

Howard    S.    Williams     (Portable) Pascagoula,    Miss.  268 

University    of    Miss Oxford.    Miis.  242 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


67 


lGVJARAJfTEf 


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Some  Real  Facts  About 
Quality 

(Continued  from  page  13) 
nently.  The  violin  and  smaller  horn 
instruments  carry  the  weight  of  the 
music.  Now,  with  the  cone  speaker 
alone,  the  drums  come  into  evidence 
with  their  steady  beat — the  chords  on 
the  piano,  the  bass  violin  with  its 
"plunk!  plunk!"  and  the  bass  saxophone. 
Neither  of  these  represents  the  orchestra 
fairly,  yet  with  both  speakers  connected, 
these  various  instruments  may  be  picked 
out  individually  and  the  effect  as  a  whole 
is  extremely  realistic. 

The  lower  notes  can  be  heard  to  a 
considerable  extent  even  with  a  trans- 
former-coupled amplifier,  so  that  these 
suggestions  are  applicable  to  both  kinds 
of  audio  amplifier. 

Fig.  3  shows  a  useful  method  of  con- 
necting the  two  loud  speakers  where  two 
tubes  are  connected  in  parallel  for  the 
last  stage  of  the  amplifier,  whether  it 
be  resistance  or  transformer  coupled. 
Each  speaker  has  a  tube  to  itself,  so 
that  the  distribution  of  output  is  fairly 
even  and  the  improvement  is  more 
noticeable  than  where  the  speakers  are 
in  parallel  as  well  as  the  tubes.  The  use 
of  a  good  power  tube,  is,  however, 
slightly  superior  to  paralleling  of  tubes 
nevertheless. 

A  simple  loud  speaker  for  low  notes  is 
illustrated  in  a  rear  view  on  page  11. 
It  is  simply  an  ordinary  mandolin  about 
10  inches  in  diameter,  having  the  unit 
of  a  Baldwin  large  type  receiver  as  an 
actuating  unit.  The  unit  is  taken  out  of 
its  case.  Fig.  5  gives  a  cross  section 
of  the  assembly.  Piece  "a"  is  a  small 
block  of  wood  about  3  34  inches  long 
and  1-2x1-2  inch  in  cross-section.  A 
J4  inch  hole  is  drilled  at  the  center  for 
passage  of  the  driving  pin  and  there  are 
two  holes  for  No.  %  machine  screws 
that  are  about  2  f£  inches  apart.  This 
forms  the  inner  clamp  for  the  unit. 
The  outer  clamp  is  of  similar  nature, 
long  enough  to  fit  very  tightly  between 
the  sides  of  the  mandolin  frame  with  a 
"forced  fit."  Thus  piece  "b,"  the  outer 
clamp,  is  merely  forced  into  position  by 
wedging  it  inside  the  mandolin.  The 
fingerboard  is  removed  to  permit  the 
assembly  of  the  unit  and  clamps.  Pieces 
"c,"  "c"  are  two  long  %  machine 
screws  for  tightening  the  clamps. 

The  driving  pin  may  be  made  of  a 
long  common  pin  with  the  head  clipped 
off.  The  diaphragm  is  cut  out  of  the 
Baldwin  unit  and  the  short  driving  pin 
already  in  it  cut  and  removed  from  the 
armature.  The  new  pin,  which  should 
be  long  enough  to  extend  from  the 
armature  to  the  mandolin  head  and 
allow  about  yi  inch  clearance  under  the 
inner  clamp  "a,"  is  inserted,  sharp  point 
first,  in  the  small  hole  in  the  armature. 
The  point  is  bent  around  to  form  a  hook 
and  it  may  be  soldered  if  desired,  although 
this  is  not  absolutely  essential.  A  hole 
is  punched  in  the  exact  center  of  the 
mandolin  head,  which  should  be  stretched 
rather  tightly  over  the  frame.  If  the 
sheepskin  is  too  loose,  it  may  be  tighened 
by  tightening  the  clamping  screws  around 
the  rim — using  the  key  wrench  made  for 
the  purpose. 

Fastening  the  Pin 

The  assembly  must  be  carefully  in- 
serted in  the  mandolin  so  that  the  pin 
passes  through  the  hole  in  the  head. 
The  frame  may  be  sprung  out  of  shape 
slightly  to  permit  the  outer  clamp  to 
enter  and  then  released  when  the  job 
is  finished.     The  pin  must  not  touch  the 

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68 


WCBM 

WCBN 

WCBQ 

WCBR 

WCBT 

WCBU 

WCBX 

WCCO 

WCEE 

WCLO 

WCLS 

WCSH 

WCTS 

WCX     ( 

WJR     j 

WDAE 

WDAF 

WDAG 

WDAR 

WDAY 

WDBA 

WDBB 

WDBC 

WDBD 

WDBE 

WDBJ 

WDBK 

WDBL 

WDBN 

WDBO 

WDBQ 

WDBR 

WDBV 

WDBX 

WDBY 

WDBZ 

WDOD 

WDWF 

WDZ 

WEAA 

WEAF 

WEAH 

WEAI 

WEAJ 

WEAM 

WEAN 

WEAO 

WEAR 

WEAU 

WEAY 

WEB 

WEBA 

WEBC 

WEED 

WFBE 

WEBH 

WEBJ 

WEBK 

WEBM 

WEBP 

WEBT 

WEBW 

WEE  I 

WEHS 


RADIO  AGE  for  October,  1925 

Charles  Swarz Baltimore,  Md.  229 

James    P.    Boland Ft.    Benj.    Harrison,    Ind.  266 

First     Baptist     Church Nashville,     Tenn.  236 

C.    H.    Messter Providence.    R.   I.  246 

Clark  University,  Collegiate  Dept Worcester,   Mass.  238 

Arnold    Wireless    Supply   Co Arnold,    Pa.  254 

Radio  Shop  of  Newark  (Herman  Lubinsky) Newark,  N.  J.  233 

Washburn-Crosby   Co Twin   Cities,    Minn.  416 

Charles  E.   Erbstein,   Villa  Olivia near  Elgin.   111.  275 

C.  E.  Whitmore Camp  Lake,   Wise.  231 

H.     M.     Couch Joliet.     111.  214 

Henry  P.  Rines Portland,  Maine  256 

C.    T.    Scherer   Co Worcester,    Mass.  268 


The  Magazine  of  the  Hour 


Press  and  Jewett    Radio  &  Phonos 


aph   Co Detroit,  Mich    516 

Fla.. 


Tampa    Daily    Times Tampa, 

Kansas  City  Star Kansas  City.    Mo. 

J.    Laurence    Martin Amarillo,    Texas 

Lit     Brothers Philadelphia,     Pa. 

Radio  Equipment  Corp Fargo.  N.  Q  ak. 

Fred  Ray Columbus,   Ga. 

A.  H.  Waite  &  Co..  Inc Taunton,  Mass. 

Kirk,    Johnson    &    Co Lancaster,    Pa. 

Herman    Edwin    Burns Martinsbure.    W.    Va. 

Gilham-Schoen    Elec.    Co Atlantic.    Ga. 

Richardson    Wayland    Electric    Corp Roanoke,    Va. 

M.   F.  Broz Cleveland,   Ohio 

Wis.  Dept.    of    Markets Stevens  Point.  W  is. 

Electric    Light    &    Power    Co Bangor,    Me. 

Rollins   College,    Inc Winter  Park,    Fla. 

Morton   Radio  Supply  Co Salem,   N.   J. 

Tremont  Temple  Baptist  Church Boston,  Mass 

The  Strand  Theatre Fort  Wayne,  Ind. 

Otto  Baur New  York,  N.  Y. 

North     Shore     Congregational     Church Chicago,     111. 

Boy  Scouts,  City  Hall Kingstown.  N.  Y. 

Chattanooga    Radio    Co.,    Inc Chattanooga,    Tenn. 

Dutee  Wilcox  Flint,   Inc Cranston,   R.   I. 

J.     L.    Bush Tuscola.    111. 

F.     D.     Fallain Flint.     Mich. 

American  Telephone  &  Telegraph  Co New  York,  N.  Y. 

Hotel    Lassen Wichita,    Kans. 

Cornell    University Ithaca.    N.    Y. 

University  of  South    Dakota Vermilion,   S.   Dak. 

Borough  of  North  Plainfield  (W.  Gibson  Buttfield) ..  North  Plainfield,  N.  J. 

Shepard  Co Providence,  R.  I. 

Ohio    State    University Columbus,    Ohio 

Goodyear   Tire   and   Rubber   Co Cleveland,   Ohio 

Davidson  Bros.  Co Sioux  City,  Iowa 

Iris  Theatre  (Will  Horowitz.  Jr.) Houston,  Texas 

Benwood  Co St.  Louis,   Mo. 

Electric    Shop Highland    Park.    N.    J. 

Walter     Cecil     Bridges Superior,     Wis. 

Electrical   Equipment   and    Service    Co Anderson,    Ind. 

Roy   W.    Walker Cambridge.    Ohio 

Edgewater  Beach    Hotel.   Chicago   Evening   Post   Station Chicago.   III. 

Third  Avenue  Railway  Co New  York.  N.  Y. 

Grand  Rapids  Radio  Co Grand  Rapids.  Mich. 

Radio   Corporation   of  America Portable 

E.   B.   Pedicord New  Orleans.   La. 

The  Dayton  Coop.  Industrial  High  School Dayton.  Ohio 

Beloit    College Beloit,    Wis. 

The  Edison  Electric  Illuminating  Co Boston.  Mass. 

Robert     E.     Hughes Evanston,     111. 

WEMC      Barrien      Springs,      Mich. 

WENR       All-American   Radio  Corporation Chicago.  Illinois 

WEW        St.    Louis    University St.    Louis,    Mo. 

WFAA       Dallas   News  &    Dallas  Journal Dallas,  Tex. 

WFAM     Times  Publishing  Co St.  Cloud,  Minn. 

WFAV       University  of  Nebraska,  Department  of  Electrical  Engineering,  Lincoln,  Nebr. 

WFBC       First    Baptist    Church Knoxville,    Tenn. 

WFRD       Gethsemane    Baptist    Church Philadelphia,    Pa. 

WFBE        Van  De  Wallc  Music  and  Radio  Co Seymour,     Ind. 

VVFBG      The  Wm.  F.   Cable  Co .Altoona,  Pa. 

WFBH       Concourse  Radio  Corporation New  York.  N.  Y. 

WFBJ        St.  John's  University Collegeville.  Minn. 

WFBO       Wynne  Radio  Co Raleigh.  N.  C. 

WFRR       Fifth  Inf.  Md.  Nat'l  Guard.  5th  Reg.  Armory Baltimore.  Md. 

WFBW      Ainsworth-Gates  Radio  Co Cincinnati.  Ohio 

WFBZ       Knox  College Galesburg.  111. 

WFI  Strawbridge  and  Clothier ...Philadelphia.  Pa. 

WFKB       Francis  K.  Bridgman Chicago,  111. 

WFUV       G.  Pearson  Ward Springfield.  Mo. 

WFUW      Earl    William    Lewis Moberly.    Mo. 

WGAL      Lancaster  Electric  Supply  &  Construction  Co Lancaster,  Pa. 

WGAO     Youree  Hotel Shreveport.  La. 

WG AZ       South  Bend  Tribune South  Bend.  Ind. 

WGRB      Harry  H.  Carman.  217  Bedell  St Freeport,  N.  Y. 

WGRC      First  Baptist  Church Memphis.  Tenn. 

WGRF      Fink  Furniture  Co Evansville.  Ind. 

WGBG      Brietenhach's  Radio  Shop Thrifton.  Va. 

WGBI        Frank  S.  Megargee Scranton,  Pa. 

JVGRK      Lawrence  Campbell Johnstown.  Pa. 

WORM     Theodore  N.  Saaty Providence.  R.  I. 

WC.RL      Elyria  Radio  Asso.  (Albert  H.  Ernst) Elyria.  Ohio 

WGBQ     Stout  Institute Menominee,  Wis. 

WGRR      Marshfield    Broadcasting    Assn ' Marshfield.  Wis. 

WGRS      Gimbel  Brothers New  York.  N.Y. 

WCBT      Furman  University Greenville.  S.    C. 

WGBX     University  of  Maine Orono,   Mo. 

WOES      Coyne  Electrical  School Oak  Park.  111. 

WG1  American   R.   &  R.  Co Medford  Hillside.  Mass. 

WGMU    A.  H.  Grebe  &  Co..  Inc..  Portable Richmond  Hill,  N.  Y. 

WON  The   Tribune Chicago,  111. 

WGR         Federal  T.  and  T.  Co Buffalo.  N.  Y. 

WGY        General  Elec.  Co Schenectady.  N.  Y. 

WHA  University  of  Wisconsin Madison,  Wis. 

WHAD      Marquette  University  and  Milwaukee   Journal Milwaukee.  Wis. 

WHAG      University  of  Cincinnati Cincinnati.   Ohio 

WHAH      Hafer  Supply  Co Joplin.  Mo. 

WHAM     University  of  Rochester  (Eastman  School  of  Music) Rochester,  N.  Y. 

WHAP       H.  Alvin  Simmons,  290  Flatbush  Ave Brooklyn.  N.  Y. 

WHAR      Seaside  House Atlantic   City,  N.  J. 

WHAS        Courier-Journal   &    Louisville  Times Louisville.   Ky. 

WHAT        Dr.  George  W.  Young Minneapolis.  Minn. 

WHAV      Wilmington  Electrical  Special ts  Co Wilmington.  Del. 

WHAZ       Rensselaer  Polytechnic  Institute Troy.  N.  Y. 

VVHB  Rweenev  School   Co Kansas   City.    Mo. 

WHRA       C.   C.   Shaffer Oil   City.   Pa. 

WHBB      Hobel's    Store Stevens    Point.    Wis. 

WHRC      Rev.  E.  P.  Graham Canton,  Ohio 

WHBD      Chas.  W.  Howard Bellefontaine,  Ohio 

WHRF      Beardsley  Specialty  Company Rock  Island.  Illinois 

WHRG      John  S.  Skane Harrisburg.  Pa. 

WHRH      Culver  Military  Academy Culver,  Ind. 

WHB  I       Lauer  Auto  Co Ft.  Wayne.  Ind. 

WHRK      Franklin  St.  Garage,  Inc Ellsworth,  Me. 

WHRL      James  H.  Slusser Logausport,  Ind. 

WHRM     C.  L.  Carroll.  Portable  Station Chicago.  111.     233 

WHBN      First  Ave.   Methodist   Church St.   Petersburg.   Florida     258 

WHBP      Johnstown  Automobile  Co •. Johnstown.  Pennsylvania     256 

WHRQ      St.  John's  M.  E.  Church  South Memphis,  Tenn.      233 

WHBR      Scientific  Electric  &  Mfg.  Co..  3661  Vine  St Cincinnati.  Ohio     216 

WHRU      Riviera  Theatre  and  Bing's  Clothing Anderson.  Ind.     218 

WHBW     D.   R.  Kienzle Philadelphia.  Pa.     215 

WHRY     St.  Norberfs  College West  De  Pore,  Wis.     250 

WHEC      Hickson  Electric  Co.,  Inc Rochester,  N.  Y.     258 

WHK         Radiovox  Company Cleveland.   Ohio     273 

WHN         George  Schubert New  York,  N.  Y.     360 

WHO         Bankers'  Life  Co Des   Moines.   la.     526 

WHT         Wrigley    Building    .  Chicago Deerfield.    HI.     238 

W!AD      Howard  R.  Miller. Philadelphia,  Pa.    254 


365 

365 

263 

393 

244 

236 

229 

258 

268 

278 

229 

227 

278 

252 

240 

234 

256 

258 

233 

258 

233 

256 

441 

278 

250 

485 

280 

286 

283 

286 

273 

293 

389 

275 

270 

273 

233 

242 

246 

248 

370 

273 

242 

226 

280 

270 

283 

475 

205 

285 

266 

280 

472 

273 

275 

250 

234 

226 

261 

273 

236 

255 

452 

309 

254 

394 

217 

252 

233 

248 

252 

360 

244 

266 

217 

226 

240 

248 

234 

227 

234 

229 

315 

236 

252 

250 

261 

236 

370 

319 

379 

535 

280 

222 

283 

278 

240 

275 

399 

231 

360 

385 

365 

250 

240 

245 

222 

222 

231 

222 

234 

231 

220 


WIAQ 

WIAS 

W1BA 

WIBC 

WIBD 

W1BG 

WIBO 

WIBH 

WIBI 

WIBJ 

WIBK 

WIBP 

WIBQ 

WIBR 

WIBS 

WIBT 

WIBU 

WIBW 

WIBX 

WIBZ 

WIL 

WIP 

WJAB 

WJAD 

WJAG 

WJAK 

WJAM 

WJAR 

WJAS 

WJAZ 

WJBA 

WJBB 

WJBC 

WJBD 

WJBI 

WJD 

WJJD 

WJR 

WCX 

WJY     ' 

WJZ 

WKAA 

WKAD 

WKAF 

WKAQ 

WKAR 

WKAV 

WKBE 

WKBF 

WKBG 

WKBK 

WKY 

WLAG 

WLAL 

WLAP 

WLAQ 

WLAX 

WLB 

WLBL 

WLS 

WLTS 

WLW 

WLWL 

WMAC 

WMAF 

WMAK 

WMAL 

WMAN 

WMAO 

WMAY 

WMAZ 

WMBB 

WMBF 

WMC 

WMCA 

WMH 

WNAC 

WNAD 

WNAL 

WNAP 

WNAR 

WNAT 

WNAX 

WNOX 

WNYC 

WOAC 

WOAE 

WOAG 

WOAI 

WOAN 

WOAO 

WOAR 

WOAT 

WOAV 

WOAW 

WOAX 

WOC 

WOCG 

WOCL 

WODA 

WOI 

WOK 

WOO 

WOR 

WORD 

WOS 

WOWL 

WOWO 

WPAB 

WPAC 

WPAJ 

WPAK 

WPAL 

WPG 

WOAA 

WOAC 

WQAE 

WO  AM 

WOAN 

WOAO 

WOJ 

WRAF 

WRAK 

WRAM 

WRAQ 

WRAV 

WRAW 

WRAX 

WRRC 

WRC 

WREO 

WRHF 

WRHM 

WRNY 

WRK 

WRL 

WRM 

WRMU 

WRW 

WSAC 


Chronicle    Publishing    Co Marion.     Ind. 

Home    Electrio    Co Burlington.    Iowa 

The    Capital-Times    Studio Madison,    Wis. 

L.  M.  Tate  Post.  No.  29.  Veterans  of  Fore  ign  Wars ...  St.  Petersburg,  Florida' 

X-L  Radio  Service Joliet,  Illinois 

at.  Paul  s  Protestant  Episcopal  Church Elkins  Park    Pa. 

Nelson     Brothers Chicago,  '  111. 

Elite-Radio  Stores New  Bedford.    Mass. 

Frederick  B.  Zitteli.  Jr Flushing  N  Y 

C.  L.  Carrel]   (Portable) Chicago    111* 

University   of    Toledo Toledo.    Ohio 

First    Presbyterian    Church Meiridian,    Miss. 

F.  M.  Schmidt Farina,  ni. 

Thurman  A.  Owings Werton,  w!  Va! 

New  Jersey  Nati  Guard  Hdqs.  Co Elizabeth    N.  J. 

Orlando  Edgar  Miller  (Portable  Station) New  York.'N.  Y. 

The  Electric  Farm Poynette.  Wis. 

Dr.- L-  L-,D'J1 Logausport,  Ind. 

Grid-Leak   Inc Utica.  N.  Y. 

Powell  Electric  Company Montgomery.  Ala. 

Continental  Electric  Supply  Co Washington    D    C 

Gimbel   Bros Philadelphia.    Pa. 

American   Electric   Co Lincoln,  Nebr. 

Jackson's  Radio  Engineering  Laboratories Waco'  Texas' 

Norfolk  Daily  News Norfolk.  Nebr. 

Clifford   L.  White Greentown,   Iowa 

D-  M-  Perham Cedar  Rapids,  Iowa 

The  Outlet  Co.  (J.  Samuels  &  Bro.) Providence,  R.  I. 

Pittsburgh    Radio   Supply  House Pittsburgh.    Pa. 

Chicago     Radio     Laboratory Chicago      111 

D.  H.    Lentz,    Jr Joliet,    111! 

L.  W.  McClurg St.  Petersburg,  Fla. 

Hummer    Furniture    Co LaSalle,    111. 

Ashland  Broadcasting  Committee Ashland     Wis. 

Robert  S.  Johnson Red   Bank.    New   Jersey 

Denison    University Granville.    Ohio 

Supreme  Lodge.  Loyal  Order  of  Moose Mooseheart,  III. 

Jewett  Radion  &  Phonograph  Co  and  Detroit  Free  Press ....  Pontiac ,  Mich. 

Radio  Corp.  of  America New  York,  N.  Y. 

Radio  Corp.  of  America New  York,  N.  Y. 

H.  F.  Paar Cedar  Rapids,  Iowa 

Chas.  Looff  (Crescent  Park) East  Providence,  R.  I. 

WKAF  Broadcasting  Co Milwaukee.  Wis. 

Radio  Corp.  of  Porto  Rico San  Juan,  P.  R. 

Michigan  Agriculture  College East  Lansing,   Mich. 

Laconia  Radio  Club Laconia.  N.  H. 

K.  &  B .  Electric  Co Webster.  Massachusetts 

Dutee  Wilcox  Flint Cranston,   Rhode  Island 

C.  L.  Carrel.  Portable Chicago    111 

Miss  Shirley  Katz New  York.  N.  Y. 

Wky  Radio  Shop Oklahoma  City,  Okla. 

Cutting  &  Washington  Radio  Corp Minneapolis  Minn. 

First  Christian  Church Tulsa,  Okla. 

Wm.  V.  Jordan Louisville.  Ky. 

Arthur   E.    Shilling Kalamazoo.    Mich. 

Putnam  Electric  Co Greencastle.  Ind. 

University  of  Minnesota Minneapolis,   Minn. 

Wisconsin  State  Dept.  of  Markets Stevenspoint,  Wis. 

Sears    Roebuck   &   Co Chicago,   II!. 

Lane  Technical  High  School Chicago,  111. 

Crosley    Mfg.    Co Cincinnati.    Ohio 

Missionary  Society  of  St.  Paul  the  Apostle New  York.  N.  Y. 

J.  Edw.  Page  (Olive  B.    Meredith) Casenovia.  N.  Y. 

Round  Hills  Radio  Corp Dartmouth,   Mass. 

Norton  Laboratories Lockport,   N.  Y. 

Trenton    Hardware    Co Trenton.    N.    J. 

First  Baptist  Church Columbus.  Ohio 

Chicago    Daily    News Chicago,    HI. 

Kingshighway  Presbyterian  Church St.  Louis.  Mo. 

Mercer    University Macon,    Ga. 

Trianon    Ball   Room Chicago.    111. 

Miami  Beach  Hotel Miami    Beach.    Fla. 

Commercial  Appeal Memphis,  Tenn. 

Hotel  McAlpin  (Greeley  Square  Hotel  Co.) New  York  City 

Ainsworth-Gates  Radio  Co Cincinnati,  O. 

Shepard     Stores Boston,     Mass. 

University  of  Oklahoma Norman.   Okla. 

Omaha  Central  High  School Omaha.  Nebr. 

Wittenberg    College Springfield.     Ohio 

First  Christian  Church Butler.  Mo. 

Lennig  Brothers   Co.   (Frederick  Lennig) Philadelphia.   Pa. 

Dakota  Radio  Apparatus  Co Yankton,  S.  Dak. 

Peoples  Tel.  &  Tel.  Co Knoxville,    Tenn. 

Dept.  of  Plant  and  Structures New  York.  N.  Y. 

Page  Organ  Co Lima.  Ohio 

Midland  College Fremont.  Nebr. 

Apollo  Theatre  (Belvidere  Amusement  Co.) Belvidere.  m. 

Southern  Equipment  Co San  Antonio.  Texas 

Vaughn  Conservatory  of  Music  (James  D.  Vaughn) ....  Lawrenceburg.  Tenn. 

Lyradion  Mfg.  Co Mishawaka,  Ind. 

Lundskow.  Henry  P Kenosha,  Wis. 

Boyd  M.  Hamp Wilmington,  Del. 

Pennsyvlania   National   Guard.   2d   Battalion.    112th    Infantry.  ..  .Erie.   Pa. 

Woodmen  of  the  World Omaha.  Nebraska 

Franklyn  J.  Wolff Trenton,  N.  J. 

Palmer  School  of  Chiropractic Davenport.  Iowa 

Triple  Alliance  Radio  Station Sycamore.     Illinois 

Hotel  Jamestown,  Inc Jamestown,   N.  Y. 

James  K.  O'Dea Paterson,  New  Jersey 

Iowa  State  College Ames,    Iowa 

Neutrowound  Radio  Mfg.  Co Homewood,     111. 

John  Wanamaker Philndelphia.  Pa. 

L.  Bamberger  and  Co Newark.  N.  J. 

Peoples  Pulpit  Assn Batavia,  TU. 

State  Marketing  Bureau Jefferson  City,  Mo. 

Owl  Battery  Company New  Orleans.  La. 

Main  Auto  Supply  Co Fort  Wayne.  Ind. 

Pennsylvania  State  College State  College.  Pa. 

Donaldson  Radio  Co Okmulgee.  Okla. 

Doolittle  Radio  Corp New  Haven,  Conn. 

North  Dakota  Agricultural  College Agricultural  College.  N.  D. 

Superior  Radio  &  Telephone  Equipment  Co Columbus.  Ohio 

The  Municipality  of  Atlantic   City Atlantic  City.  N.  J. 

Horace  A.  Beale.  Jr Parkersburg.  Pa. 

E.  B.  Gish Amarillo.  Texas 

Moore  Radio  News  Station  (Edmund  B.  Moore) Springfield,  Vt. 

Electrical  Equipment  Co Miami,  Fla. 

Scranton  Times Scranton.  Pa. 

Calvary  Baptist  Church New  York.  N.  Y. 

Calumet  Rainbo  Broadcasting  Co Chicago.  111. 

The  Radio  Club  (Inc.) Laporte.  Ind. 

Economy  Light  Co Escabana,  Mich. 

Lombard  College Galesburg,  111. 

St.  Louis  Radio  Service  Co St.  Louis.  Mo. 

Antioch  College Yellow  Springs.  Ohio 

Avenue  Radio  Shop  (Horace  D.  Good) Reading.  Pa. 

Flaxon's  Garage Gloucester.  City  N.  J. 

Imanuel  Lutheran  Church Valparaiso.  Ind. 

Radio  Corp.  of  America Washington.  D.  C. 

Reo  Motor  Car  Co Lansing,  Mich. 

Washington  Radio  Hospital  Fund Washington.  C.  D. 

Rosedale  Hospital.  Inc.* Minneapolis,  Minn. 

Experimenter  Publishing  Co New  York.  N.  Y. 

Doron   Bros Hamilton,    Ohio 

Union  College Schenectady,  N.  Y. 

University  of  Illinois Urbana.  III. 

A.  H.  Grebe  4t  Co.,  Inc.,  Motor  Yacht  "MU-1" New  York,  N.  Y. 

Tarrytown  Radio  Res.  Labs Tarrytown,  N.  Y. 

Clemson  Agricultural  College Clemson  College.  S.  C. 


226 
283 
236 
222 
200 
222 
226 
209 
219 
216 
205 
210 
205 
246 
203 
211 
222 
220 
205 
231 
360 
509 
229 
352 
283 
254 
268 
306 
286 
268 
207 
207 
234 
233 
219 
229 
303 
517 

455 
455 
278 
240 
261 
340 
285 
254 
231 
286 
216 
210 
275 
417 
250 
286 
283 
231 
278 
278 
344 
258 
422 
288 
261 
440 
273 
256 
286 
447 
280 
261 
250 
384 
503 
341 
321 
284 
258 
255 
271 
230 
254 
248 
268 
526 
260 
280 
274 
392 
230 
369 
225 
360 
242 
526 
240 
484 
205 
275 
203 
270 
217 
509 
405 
275 
440 
270 
227 
283 
360 
268 
283 
286 
300 
270 
234 
275 
283 
280 
260 
447 
224 
256 
244 
263 
242 
238 
268 
278 
468 
286 
256 
252 
258 
360 
270 
273 
236 
273 
336 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


69 


(Continued  from  page  67) 
inner  clamp  or  the  coils  in  the  unit. 
The  pin  is  rotated,  in  case  the  soldered 
method  hasn't  been  used,  so  that  the 
bent  end  cannot  touch  the  receiver 
coils,  or  the  magnets.  A  few  drops  of 
sealing-wax  on  the  head  of  the  mandolin 
and  on  the  pin  serve  to  complete  the 
speaker.  The  result  is  not  a  speaker 
that  accentuates  high  notes  in  particular, 
its  chief  field  being  in  the  lower  range. 
Hence,  while  suitable  for  independent 
operation  for  certain  kinds  of  reception, 
its  use  as.  an  accompaniment  to  a  horn 
speaker  is  the  chief  consideration   here. 

In  adjustment,  the  position  of  the 
outer  clamp  depends  upon  the  strength 
of  the  current  through  the  windings. 
Moreover,  the  direction  of  current 
through  the  windings  must  be  such  that 
upon  closing  the  plate  circuit  of  the  tube 
(as  by  inserting  the  jack)  the  pin  will 
pull  (not  push)  upon  the  mandolin  head. 
This  may  be  felt  on  the  head  or  may  be 
seen  by  watching  the  slight  movement 
of  the  armature  in  the  unit.  Care  must 
be  taken  not  to  disturb  the  opposing 
spring  located  at  the  other  end  of  the 
armature. 

This  auxiliary  speaker  may  be  located 
underneath  a  table  in  the  room,  near 
the  horn  speaker  and  it  may  be  con- 
nected either  in  series  or  in  parallel  with 
it.  Both  connections  should  be  tried. 
The  outer  clamp  should  be  set  so  that 
no  rattling  occurs  during  reception — 
this  being  found  with  the  proper  tension 
on  the  head. 

In  this  manner,  or  by  supplementing 
the  horn  loud  speaker  with  a  device 
capable  of  reproducing  the  lower  notes, 
the  radio  receiver  as  a  whole  becomes  a 
more  faithful  repeater  of  what  is  going 
on  at  the  broadcasting  studio.  Coupled 
with  an  improved  audio  amplifier,  the 
radio  set  as  the  Home  Theater  comes 
into   its   intended   role   in    full    measure. 


Aiding  Condenser  Handling 

Thousands  of  radio  fans  have  dis- 
covered that  by  the  simple  process  of 
pressing  on  their  condenser  dials  they 
can  tune  one  station  in  and  another  out. 
The  majority  of  them  do  not  realize  that 
this  is  extremely  bad  practice,  and  if 
persisted  in  will  ultimately  ruin  the 
bearings  of  the  condenser.  This  condi- 
tion only  exists  where  the  two  stations 
are  close  together  in  frequency  and  are 
crowded  on  the  dial  settings. 

The  obvious  solution  to  this  condition 
was  early  realized.  It  consisted  of  a 
tuning  mechanism  which  would  move 
the  rotary  plates  of  the  condenser  very 
slowly  over  the  smallest  possible  distance 
in  order  to  get  the  very  minute  change  in 
capacity  needed  to  tune  the  receiver  to 
the  frequency  of  the  particular  broad- 
casting station. 

This  led  to  the  many  various  types  of 
so-called  "Vernier  dials."  The  difficulty 
up  to  the  present  however  has  been  two- 
fold; first,  the  use  of  gears  in  these  dials 
resulted  in  a  certain  amount  of  blacklash 
which  prevented  the  condenser  from  re- 
maining in  a  certain  position;  and,  second, 
the  condenser  design  itself  was  not  cor- 
rect for  accurate  tuning  on  the  higher 
frequencies. 

The  latest  type  of  vernier  dial,  known 
as  the  Microvern,  employs  an  extremely 
simple  mechanical  principle  which  pro- 
duces a  reduction  in  turning  movement 
of  five  to  one  without  the  use  of  gears. 
The  reduction  ratio  of  five  to  one  has 
been  found  good  under  all  normal  con- 
ditions, as  it  is  fast  enough  for  rapid 
station  finding,  and  slow  enough  for  care- 
ful final  adjustment. 


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Everyone  wants  one  of  these  revolutionary  receivers  that  are         . 
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The  new  Erla 
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The  amazing  new  inductance  principle 
found  in  these  kits  belongs  to  Erla  alone. 
No  other  set  regardless  of  price,  can 
offer  it  to  you.  It  is  based  on  a  different 
kind  of  coil — The  Erla  *Balloon  *Cir- 
cloid.     Four  striking  advantages  result: 

1.  Greater  Distance.  Circloids  have 
no  measurable  external  field  to  affect 
adjacent  coils  or  wiring  circuits.  This 
makes  possible  higher  amplification-  in 
each  stage,  with  increased  sensitivity 
and  greater  range. 

2.  More  Volume.  Higher  r.  f.  am- 
plification enables  Circloids  to  bring 
in   distant   stations   scarcely   audible   in 


ordinary  sets  with  volume  enough  to 
fill  an  auditorium. 

3.  Increased  Selectivity.  Circloids 
have  absolutely  no  pickup  qualities  of 
their  own.  Only  signals  flowing  in  the 
antenna  circuits  are  built  up. 

4.  Finer  Tone  Quality.  The  self- 
enclosed  field  positively  prevents  stray 
feed-backs  between  coils.  Hence  no 
blurring  or  distortion.  Tones  are  crystal 
clear. 

Write  for  free  information  on  kit — also  book 
See  how  a  few  minutes  of  fun  will  give  you  the  new- 
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ed in  the  remarkable  book,  "Circloid  Hookups." 


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selectivity,  diBtance,  volume,  workmanship  and  price. 
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P-l  Kit  Saves  Yon  Money  t 

Our  offer  of  the  Telmaco  P-l  Receiver  in  kit  form  has 
met  with  enthusiastic  reception.  This  contains  all 
parts,  as  built  by  us,  including  case,  drilled  and  en- 
graved panel,  and  illustrated  instructions.  $Q  A  00 
Complete  kit  .       .        -,    ,  •    .  ,.    YT 

Askyourdealeror  write  us.  Descriptive  folder  free. 

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20  So.  Wells  St.    Dept.  C   Chicago,  111. 


Quality  <Hadio  exclusively   •%>    established  1918 


SPEAKER 
WITH 

CONCERT 
UNIT 


The  Heart  of  the  Speaker 

Large  size  and  scientific  construction  of 
the  Concert  Unit  gives  remarkable  tone 
values  which  combined  with  the  special 
amplifying  properties  of  the  BURNS 
horn  produce  wonderful  results. 


BURNS  horn  is  of  a  dis- 
tinctive design  with  pyralir 
flare  in  several  handsome 
finishes — It  pleases  the  eye 
as  well  as  the  ear. 


MAKERS 

American  <§/ecfrrc (prnpaw/ 

State  and  64th  Sta.,  Chicago,  U.  S.  A. 


*     Tested  and  Approved  by  RADIO  AGE     * 


70 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


WWGS     Radio  Engineering  Coro Richmond  Hill.  N.  Y. 

WSAI        United  States  Playing  Card  Co Cincinnati .  Ohio 

WSAJ       Grove  City  College Grove  City.  Pa. 

WSAN       Allentown  Call  Publishing  Co Allentown.  Pa. 

WSAP       Seventh  Day  Adventist  Church New  York.  N.  Y. 

WSAR       Daughty  &  Welch  Electrical  Co Fall  River.  Maes. 

WSAU       Camp  Marienfield Chesham,   New  Hampshire 

WSAV       C.  W.  Viok  Radio  Construction  Co Houston,  Texas 

WSAY  Irving  Austin  (Port  Chester  Chamber  of  Commerce) .  .  .Port  Chester,  N.  Y. 

WSAZ       Chaa.  Electric  Shop Pomeroy.  Ohio 

WSBF       Stix-Baer-Fuller  D.  G.  Co St.  Louis,  Mo. 

WSBC      World  Batley  Co 1219  S.  Wabash  Ave.,  Chicago.  111. 

WSB        '  Atlanta  Journal Atlanta,  Ga. 

WSKC      World's  Star  Knitting  Co Bay  City,  Mioh. 

WSMB     Saenger  Amusement  Co.  and  Maison  Blanche  Co New  Orleans,  La. 

WSMH     Sbattuck  Music  House Owoseo.  Mioh. 

WSMK     8.  M.  K.  Radio  Corp Dayton.  Ohio 

WTAW     Agricultural  &  Mechanical  College  of  Texas College  Station,  Texas 

WTAM     Willard  Storage  Battery  Co Cleveland,  Ohio 

WTAX      Williams  Hardware  Co Streator,  111. 

WTAZ       Thomas  J.  McGuire Lambertville,  N.  J. 

WTHS      Flint  Senior  High  School Flint.  Mich. 


213 

WTG 

325 

WTIC 

258 

WTX 

229 

WW  AD 

263 

WWAE 

254 

WWI 

229 

WWJ 

360 

WWL 

233 

WSOE 

258 

WSRF 

275 

WSTA 

210 

WSUI 

428 

WTAB 

261 

WTAC 

319 

WTAD 

240 

WTAL 

275 

WTAP 

280 

WTAQ 

390 

WWGL 

231 

WTAR 

283 

WTAS 

218 

WTAT 

Kansas  State  Agricultural  College Manhattan,  Kans.  273 

Travelers  Insurance  Co Hartford,  Conn.  323 

H.  G.  Saal  Co Chicago,  111.  26o 

Wright  &  Wright  (Inc.) Philadelphia.  Pa.  360 

The  Alamo  Ball  Room Joliet,  111.  242 

Ford  Motor  Co Dearborn,  Mich.  273 

Detroit  News  (Evening  Newa  Assn.) Detroit,  Mioh.  352 

Loyola  University New  Orleans,  La.  260 

School  of  Engineering Milwaukee,  Wis.  246 

Hardem  Sales  and  Service Broadlands,  111.  233 

Camp  Marienfeld Chesham,  N.  H.  229 

State  University  of  Iowa Iowa  City,  Iowa  498 

Fall  River  Daily  Herald  Publishing  Co Fall  River,  Mass.  248 

Penn  Traffic  Co Johnstown,  Pa.  360 

Robt.  E.  Compton Carthage,  111.  236 

Toledo  Radio  &  Electric  Co Toledo.  Ohio  252 

Cambridge  Radio  &  Electric  Co Cambridge,  111.  242 

S.  H.  Van  Gordon  &  Son Oaseo,  Wis.  220 

Radio  Engineering  Corp Richmond    Hill,    N.    Y.  213 

Reliance  Electric  Co Norfolk,  Va.  283 

Charles  E.  Erbstein Elgin,  111.  304 

Edison  Electric  Illuminating  Co (portable)  Boston,  Mass.  240 


Canadian  Stations 


CFAC  Calgary  Herald Calgary.    Alta. 

CFCA  Toronto  Star  Pub.  &  Prtg.  Co Toronto.  Ont. 

CFCF  Marconi  Wireless  Teleg.  Co.,  (Ltd.)  Canada Montreal,  Que  . 

CFCH  Abitibi  Power  &  Paper  Co.,  (Ltd.) Iroquois   Falls,  Ont. 

CFCK.  Radio  Supply  Co Edmonton.  Alta. 

CFCN  W.  W.  Grant  (Ltd.) Calgary,  Alta. 

CFCR  Laurentide  Air  Service Sudbury,  Ont. 

CFCT  Victoria  City  Temple Victoria.  B.  C. 

CFCU  The  Jack  Elliott  (Ltd.) Hamilton,  Ont. 

CFHC  Henry  Birks  &  Sons Calgary.  Alta. 

CFKC  Thorold  Radio  Supply Thorold.   Ont. 

CFQC  The  Electric  Shop  (Ltd.) Saskatoon,  Sask. 

CFRC  Queens  University Kingston,  Ont. 

CFXC  Westminster  Trust  Co Westminister,  B.  C. 

CFYC  CommercialRadio  (Ltd.) Vancouver,   B.  C. 

CHBC  The  Calfrary  Albertan Calgary,  Alta. 

CHCM  Riley  &  McCormaok  (Ltd.) Calgary,  Alta. 

CHCS  The  Hamilton  Spectator Hamilton,  Ont. 

CHIC  Northern  Electric  Co Toronto.  Ont. 

CHNC  Toronto  Radio  Research  Society Toronto.  Ont. 

CHUC  International  Bible  Ass 'n Saskatoon,  Saak. 

CHXC  R.   Booth,  Jr Ottawa.  Ont. 

CHYC  Northern  Electric  Co Montreal,    Que. 


434 

CJCA 

357 

CJCL 

411 

CJGC 

500 

CKAC 

517 

CKCD 

434 

CKCK 

410 

CKCO 

329 

CKCX 

341 

CKFC 

434 

CKLC 

248 

CKNC 

329 

CKOC 

450 

CKY 

291 

CNRA 

411 

CNRC 

434 

CNRE 

434 

CNRM 

341 

CNRO 

357 

CNRR 

357 

CNRS 

329 

CNRT 

434 

CNRV 

411 

CNRW 

Edmonton  Journal Edmonton,  Alta.  51 1 

A.  Couture Montreal,  Que.  279 

London  Free  Press London,  Ont.  321 

La  Presse Montreal,  Que.  411 

Vancouver  Daily  Province Vancouver,  B.   C.  397 

Leader  Pub.  Co ." .  .Regina,  Sask.  476 

Ottawa  Radio  Association Ottawa,  Ont.  434 

P.  Burns  &  Co.,  (Ltd.) Calgary,  Alta.  434 

First  Congregational   Church Vancouver,   B.  C.  411 

Wilkinson  Electric  Co.,  (Ltd.) Calgary,    Alta.  434 

Canadian  National  Carbon  Co Toronto,  Ont.  357 

Wentworth  Radio  Supply  Co Hamilton,    Ont.  341 

Manitoba  Tel.  System Winnipeg,  Man.  384 

Canadian  National  Railways . .  Moncton,  N.  B.  312 

Canadian  National  Railways Calgary,  Canada  434 

Canadian  National  Railways Edmonton,  Alta.  517 

Canadian  National  Railways Montreal,  P.  Q.  411 

Canadian  National  Railways Ottawa.  Ont.  434 

Canadian  National  Railways Regina,   Sask.  476 

Canadian  National  Railways Saskatoon,  Sask.  329 

Canadian  National  Railways Toronto,    Ont.  357 

Canadian  National  Railways Vancouver,  B.  C.  411 

Canadian  National  Railways Winnipeg,    Man.  384 


Cuban  Stations 


PWX  Cuban  Telephone  Co Habana  400  2K 

2DW  Pedro  Zayas ; Habana  300  2HS 

2AB  Alberto  S.  de  Bustamante Habana  240  20L 

20K.  Mario  Garcia  V«Iez Habana  360  2WW 

2B Y  Frederick  W.  Borton Habana  260  5EV 

2CX  Frederick  W.  Borton Habana  320  6KW 

2EV  Westinghouse  Elec.  Co Habana  220  6KJ 

2TW  Roberto  E.  Ramires Habana  230  6CX 

2HC  Heraldo  de  Cuba Habana  275  6DW 

2LC  Luis  Casas Habana  250  6BY 

2KD  E.  Sanchez  de  Fuente3 Habana  350  6AZ 

2MN  Fausto  Simon t Habana  270  8BY 

2MG  Manuel  G.  Salas Habana  280  8FU 

2JD  Raul  Parez  Falcon Habana  105  8DW 


Alvara  Daza Habana  200 

Julio  Power Habana  180 

Oscar  Collado Habana  290 

Amadeo  Saenz Habana  210 

Leopoldo  E.  Figueroa Colon  360 

Frank  H.  Jones Tuinucu  340 

Frank  H.  Hones Tuinucu  275 

Antonio  T.  Figueroa CienfiegoB  170 

Eduardo  Terry Cienfiegos  225 

Jose  Ganduxe Cienfiegos  300 

Valentin  UUivarri Cienfiegos  200 

Alberto  Ravelo Stgo.  de  Cuba  250 

Andres  Vinnet •. Stgo.  de  Cuba  225 

Pedro   C.  Anduz Stgo.  de  Cuba  275 


European  Broadcasting  Stations 


British  Stations 


2LO  London 365  SNO 

SIT  Birmingham 475  5SC 

5WA  Cardiff 350  2BD 

6BM  Bournemouth 3S5  6SL 

2ZY  Manchester... 375 


Newcastle 400 

Glasgow 420 

Aberdeen 492 

Sheffield  (relay  station) 303 


French  Stations 


Stewart-Warner  Opens  a 
Studio 

Last  Saturday  night,  August  1,  marked 
the  opening  of  one  of  Chicago's  newest 
and  most  beautiful  broadcasting  studios. 
This  studio  is  owned  and  operated  by  the 
Stewart- Warner  Speedometer  Corpora- 
tion, and  is  located  at  1826  Diversey 
Parkway. 

The  construction  is  of  the  latest  and 
most  scientific,  using  a  special  material 
which  does  not  deaden  the  tone  of  the 
instrument  or  the  voice,  but  retains  it  in 
all  its  naturalness  and  at  the  same  time 
prevents  any  reverberations  that  have  a 
tendency  to  jumble  the  music. 

The  fine  manner  in  which  this  station 
has  been  received  all  over  the  country 
shows  the  important  part  that  the  studio 
construction  plays  in  the  satisfactory 
broadcasting  of   programs. 

This  studio  is  equipped  with  two 
Baldwin  special  broadcast  grand  pianos, 
a  Wurlitzer  harp,  a  beautiful  announcer's 


desk,  which  is  an  exact  copy  of  the  desk 
used  by  George  Washington  in  the  White 
House. 

The  furnishings,  selected  with  great 
care,  are  in  perfect  keeping  with  the 
beautiful  surroundings.  The  entire  color 
scheme  blends  in  a  most  delightful  man- 
ner, creating  an  atmosphere  of  harmony. 

The  studio  is  a  departure  from  the 
usual  draped  studio,  which,  it  is  said, 
greatly  adds  to  the  comfort  of  the  artists, 
being  cool  and  pleasant  even  in  the 
hottest    weather. 

The  beautifully  appointed  reception 
room  adjoining  the  studio  provides  every 
convenience  for  the  waiting  artists. 
It  is  furnished  with  a  console  model, 
Stewart- Warner  Matched-Unit  Radio 
which  reproduces  the  program  just 
as  it  is  being  broadcast,  providing  enter- 
tainment for  those  who  are  waiting  their 
turn  to  go  on  the  air. 

All  programs  from  this  station  are  broad- 
cast on  a  226  meter  wavelength  over  Sta- 
tion WBBM. 


Mohawk  Electric  Corporation 
Announcements 

Announcement  is  made  by  the  Mohawk 
Electric  Corporation  of  Chicago,  that 
they  have  recently  completed  arrange- 
ments with  The  Zinke  Company  of 
Chicago  to  sell  the  entire  line  of  Mohawk 
Products.  The  Zinke  Company,  who 
have  been  established  for  20  years,  will 
maintain  their  policy  of  selling  through 
the  jobber  Mohawk  Receiving  Sets  and 
Mokawk  Parts.  An  extensive  selling 
campaign  is  planned  for  the  sale  of  the 
Mohawk  One  Dial  Receiving  Sets. 

The  Mohawk  Electric  Corporation 
announce  a  revision  downward  of  prices 
on  their  line  of  receiving  sets  which  have 
"Just  ONE  Dial  to  Tune." 

The  Model  VA,  now  known  as  Model 
100  is  priced  at  $100.00. 

Model  X  is  reduced  from  $250.00  to 
$175.00,  while  model  XII  was  formerly 
sold  for  $300.00  now  $275.00. 


RADIO  AGE  for  October,  1925 


The  Magazine  of  the  Hour 


71 


CLASSIFIED  ADVERTISEMENTS 

If  you  have  anything  to  buy  or  sell,  don't  overlook  the  value  of  RADIO  AGE'S  classified 
advertisements.    Many  such  messages  have  paved  the  way  to  independent  incomes. 

The  classified  advertising  rates  are  but  ten  cents  per  word  for  a  single  insertion.  Liberal 
discounts  are  allowed  on  three,  six  and  twelve-time  insertions,  of  five,  fifteen  and  thirty  per  cent 
respectively.  Unless  placed  through  an  accredited  advertising  agency,  cash  should  accompany 
all  orders.  Name  and  address  must  be  included  at  foregoing  rates  and  no  advertisement  of  less 
than  ten  words  will  be  accepted. 

All  classified  ads  for  the  November  issue  must  be  sent  in  by  October  1. 


ADVERTISING     SERVICE 


QUEX  Sales    Letters   Get   More   Busine 
today.      Quex,  4418  Michigan  Ave.,  Chit 


ENGINEERS  about  to  begin  six-months'  research  trip 
to  territory  West  of  the  Mississippi,  between  Canada  and 
Mexico,  are  willing  to  consider  propositions  for  taking 
on  radio  lines  on  a  distribution  basis,  with  a  view  to 
establishing  dealers,  jobbers,  agents,  etc.,  in  sparsely 
settled  districts.  Such  territory  would  be  exclusively 
apportioned.  Address  all  communications  in  confi- 
dence. Only  reputable  lines  and  concerns  will  be  con- 
sidered. 100  per  cent  distribution  and  advertising 
representation  assured  at  minimum  per  capita  cost. 
Address,  Harvey  T.  Kelley,  Suite  301,  210  East  Ohio 
Street,  Chicago,  III. 


AGENTS  WANTED 


FORDS.     60 
proven   such 
antees  to 
boiling  in 
Decarbon 


es  on  one  gallon  of  Gas.      It  has  been 

leage  can  be  made.     AIRLOCK  guar- 

gas  mileage;  also  prevents  radiator 

or  freezing  in  winter.     Cools,  Fuels, 

Ford     motor.       Splendid     territory 


RADIO — Join  our  sales  organization  and  make  big 
money.  We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers. Widener  of  Kansas  City  makes  $150.00 
weekly.  You  can  do  as  well  or  better.  Write  today 
for  catalog,  and  discounts.  Name  your  county.  Wave- 
land  Radio  Company,  Div.  52,  1027  No.  State  St.,  Chi- 
cago,  111. 


MANUFACTURER'S  AGENT  calling  on  Radio-Elec- 
trical Jobbers,  Chicago  and  vicinity,  has  opening  for  3 
additional  lines  carrying  volume  business,  as  we  cater 
to  large  jobbers.  Edelstein,  1804  McCormick  Bid., 
Chicago. 


AGENTS— WRITE  FOR  FREE  SAMPLES.  Sell  Madison 
"Better-Made"  Shirts  for  large  manufacturer  direct  to 
wearer.  No  capital  or  experience  required.  Many 
earn  $100  weekly  and  bonus.  MADISON  MFGRS.,  501 
Broadway,  New  York. 


90c  an  h 
America 

our  to  advertise  and  distribu 
Write    quick     for    territory 
n  Products  Co.,  2130  Americ 
Ohio. 

te  samples  to  con- 
and     particulars. 
an  Building,  Cin- 

Man  wanted  for  this  territory  to  sell  wonderful 
value  men's,  women's,  Children's  shoes  direct,  sav- 
ing consumer  over  40%.  Experience  unnecessary. 
Samples  supplied.  Big  weekly  permanent  income. 
Write  today  Tanners  Mfg.  Co.,  1334C.  St.,  Boston,  Mass. 

RADIO  SALESMEN  and  SET  BUILDERS  in  every  county 
write  Grenzer  Radio,   1479   Hodiamont,  St.   Louis,   Mo. 


<B"    BATTERIES 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parti  and  plan. — complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake,  Chicago. 


BATTERIES  FOR  SALE— Four  24-rolt  "Main"  Storage 
"B"  Batteries,  never  used,  shipped  and  ready  to  wire 
for  $38.00.  First  order  gets  the  batteries.  Address 
Box  B,  Radio  Age,  500  N.  Dearborn  St.,  Chicago,  III. 


BUSINESS  OPPORTUNITIES 


ekly 


time.     BarReld  Radio 
Brooklyn,  New  York. 


It  experienced  Radio  men  to 
ing  plants.  Part  or  whole 
,  13  Tillery  Street,  Dept.  A  R, 


Classified  ad.  copy  for  the  Novem- 
ber RADIO  AGE  must  be  sent  in 
by  October  1,  1925. 


CRYSTALS 


Supersensitive  Galena   Crystals:   Pound  $1.00, 
ALKEMITE.        Allsensitive      Crystals      50c. 
Geologist,  Joplin,  Missouri. 


HELP  WANTED 


.nd  SET  BUILDERS— We  need 
If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  111. 


MEN  wanting  forest  ranger,  railway  clerk  and  other 
government  positions,  write  for  free  particulars  of 
Mokane,    Dept.   B-33.    Denver,   Colo. 


INVENTIONS 


NEW  IDEAS  WANTED— Well  known  Radio  Manufac- 
turer whose  products  are  nationally  advertised  and  sold 
everywhere  wants  new  Radio  device  to  sell.  Will  pay 
outright  or  royalty  for  idea  or  invention  which  is  really 
new  and  saleable.  Address:  Mr.  R.  F.  Devine,  Room 
1101.  116  West  32nd  St.,  New  York.  N.  Y. 


PATENTS 


FOR  SALE:  U.  S.  and  Canadian  Patent  on  an  Attach- 
ment for  Phonographs;  is  the  most  beautiful  inven- 
tion of  the  age.     Address  Chas.  F.  Smith,  Huff,  N.  Dak. 


PERSONAL 


LONELY  HEARTS:  Exchange  letters;  make  interesting 
new  friends  in  our  jolly  club.  Eva  Moore,  Box  90S, 
Jacksonville,  Florida.    Enclose  stamp. 

Lookl  You  Radio  Bugs!  Join  Radio  Correspondence 
Club.  Entirely  new.  Broaden  your  acquaintance, 
exchange  ideas.  Membership  open  to  LADY  BUGS 
also.  Dime  stamp  brings  pamphlet  and  Radio  Novelty 
Cards.     Radio  Rose,  Box  662,  Cleveland,  Ohio. 


PRINTING 


WE    print    Stationery,    Booklets,    Catalogs,    Circular! 
Samples.     Commercial  Press,  Batavia,  Ohio. 


RADIO 


A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  111. 

Standard  soderless  radio  Jacks.  Binding  post  attach- 
ments. Double  circuit.  One  dollar  bill.  Postpaid. 
Clinton  Seward,  Jr..   New  Paltz,  New  York,  N.  Y. 

Three  Cosmopolitan  Phu  si  formers,  each  $5.50,  book  of 
instructions  included.      F.  A.   Mall,  Triopli,    Iowa. 

15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.  Every  item  guaranteed.  Tell  us  your  needs. 
IMPERIAL  RADIO  COMPANY.  Delaware,  Ohio. 

RADIO  SETS.  Our  prices  save  you  money.  Lists  free. 
The  Radio  Shoppe,  Box  645,  East  Liverpool,  Ohio. 

AT  LAST  The  Radco  Static  Eliminator.  Eliminates 
50  to  90%  Static.  Many  satisfied  users.  Write  for 
particulars.  Radio  Specialties  Company,  Sioux  Falls, 
South    Dakota. 


RADIO  CIRCUITS 


SPECIAL  FOR    OCTOBER 
The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne,  fully 
illustrated,  and  RADIO  AGE,  for  $2.50.      Price  of  Book- 
let alone  is  50c.      Send  check,  currency  or  money  order 
to  RADIO  AGE,  500  N.  Dearborn  Street,  Chicago. 

*     Tested  and  Approved  by  RADIO   AGE      * 


RADIO  DEALERS 


DEALERS— Write  for  our  illustrated  catalog  of  reliable 
Radio  Merchandise.  Rossiter-Manning  Corporation, 
Dept.  D,  1830  Wilson  Ave.,  Chicago,  111. 


RADIO  SUPPLIES 


:  CAN  SAVE  You  money  . 
t    discount   AND    MORE 
akers,  static  eliminators. 


tube 


upplies.  30  per 
batteries,  loud 
'8,  transformers 
rman  silver  wire,  and  all  standard  radio  apparatus* 
;  buy  in  quantity  lots  to  enable  selling  to  you  whole- 
e.  Additional  discount  for  cash.  Send  for  catalog 
exclusive  proposition  for  your  territory.  Address, 
x  9A,  RADIOGRAPH  LABORATORIES,  1234  Rose- 
,  Chicago,  III.      New  fall  lines  now  ready. 


SALESMEN  WANTED 


Make  $100  WEEKLY  in  spare  time.  Sell  what  the 
public  wants — long  distance  radio  receiving  sets.  Two 
sales  weekly  pays  $100  profit.  No  big  investment, 
no  canvassing.  Sharpe  of  Colorado  made  $955  in  one 
month.  Representatives  wanted  at  once.  This  plan 
is  sweeping  the  country — write  today  before  your 
county  is  gone.  OZARKA,  INC.,  126  West  Austin  Ave., 
F-,  Chicago. 


STAMPS,  50  varieties,  Africa,  Brazil,  Peru,  Cuba, 
Mexico,  etc.,  10c.  50  different  U.  S.,  25c;  1,000  mixed, 
40c;  1,000  hinges,  10c.  List  free.  C.  Stegman,  5950 
Cote  Brilliante,  St.  Louis,  Mil 


VOCATIONS 


WANTED 


WANTED — To  complete  my  set  RADIO  AGE  need 
August,  September,  October,  November,  1923,  Issues, 
bound  or  unbound.  Advise  price.  Lloyd  C.  Henning, 
Hollbrook.  Arizona. 


WIRELESS 


WANT  TO  MEMORIZE  THE  WIRELESS  CODE?  The 
Coryden  Snyder  Code  Method,  Patented,  is  quickest. 
Send  50c  coin,  stamps  or  M.  O.  to  C.  G.  Snyder.  1423 
Elmdale  Ave.,  Chicago.  111. 

TELEGRAPHY— Morseand  Wireless— taught  at  home 
in  half  usual  time  and  at  trilling  cost.  Omnigraph 
Automatic  Transmitter  will  send,  on  Sounder  or  Buz- 
zer, unlimited  messages,  any  speed,  just  as  expert 
operator  would.  Adopted  by  U.  S.  Govt,  and  used  by 
leading  Universities,  Colleges,  Technical  and  Telegraph 
Schools  throughout  U.  S.  Catalog  free.  Omnigraph 
Mfg.  Co.,  13  F  Hudson  St.,  New  York. 


WRITERS 


NEW  WRITERS  WANTED— Articles,  stories,  poems, 
scenarios,  etc.  $13,500  just  paid  to  unknown  writer. 
Entirely  new  field.  (No.  bunk.)  NOT  A  CORRE- 
SPONDENCE COURSE.  Moving  picture  industry  and 
publishers  crying  for  new  original  material.  YOU 
CAN  DO  IT.  We  buy  manuscripts  for  books  and  mag- 
azines. Send  self  addressed  envelope  for  list  of  100 
subjects.  CALIFORNIA  STUDIOS,  P.  O.  Box  697,  Los 
Angeles,  Calif. 


WRITERS— Cash  in  on  your  knowledge  of  radio  by 
writing  for  Radio  Magazines  and  Newspaper  Supple- 
ments. Write  up  your  radio  experiences,  your  new 
hook-up,  your  knowledge  of  broadcasting  stations  and 
artists.  Experienced  authors  will  correct  and  improve 
your  manuscripts  make  them  typically  professional 
work.  FREE  Criticism  and  Advisory  Service  until  your 
manuscript  is  soldi  ALL  Magazines  and  Papers  de- 
manding fiction  and  articles  dealing  with  radio.  Here 
is  YOUR  OPPORTUNITY  to  profit!  Send  for  FREE 
booklet,  "How  You  Can  Sell  Your  Manuscripts." 
Willis  Arnold  and  Associates,  210  East  Ohio  St. 
Chicago,  111. 


Make  big  money  writing  Movie  Plays.     Circulars  free 
W.    C.    Krug,   Ashton,    Illinois. 


Have  you  ordered  your 
November  Radio  Age? 


72 


RADIO  AGE  for  October,  1925 


The  Magazitie  of  the  Hour 


THE    RADIO    AGE 
BUYERS'    SERVICE 

What  do  you  want  to  purchase  in  the  radio  line?  Let  the  staff  of  RADIO  AGE  save  you 
time  and  money  by  sending  in  the  coupon  below.  Enter  the  number  of  the  article  you 
would  like  to  know  more  about  in  the  spaces  provided  in  the  coupon. 


1  "A"  Batteries 

2  Aerial  protector* 

3  Aerial  insulators 

4  Aerials 

5  Aerials,  loop 

6  Amplifiers 

7  Amplifying  units 

8  Ammeters 

9  "B"  batteries 

10  Batteries   (state  voltage) 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery  substitute* 

17  Bezels 

18  Binding  posts 

19  Binding  posts,  Insulated 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatstone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzzers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisers 

33  Coils 

34  Coils,  choke 

35  Coils,  coupling 

36  Coils,  filter 

37  Coils,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance 

40  Coils,  Reinartz 

41  Coils,  stabilizer 

42  Coils,  tuning 

43  Condenser  parts 


46  Conde 

47  Conde 

48  Conde 

49  Conde 
grid,  o 

50  Conde 

51  Conde 

52  Conde 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  oets 

57  Couplers,  loose 

58  Couplers,  molded 

59  Couplers,  vario 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  units 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 

71  Dial,  adjusters 

72  Dials,  composition 

73  Dials,  hard  rubbor 

74  Dials,  rheostat 

75  Dials,  metal 

76  Dials,  vernier 

77  Dials  with  knobs 

78  Dies 

79  Drills,  electric 

80  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

83  Enamels,  battery 

84  Enamels,  metal 

85  End  stops 

86  EyeleU 

87  Experimental  work 

83  Fibre  sheet,  vulcanized 

89  Filter  reactors 

90  Fixture* 


■pho 


able 


91    Fu 


Out  3 


92  Fuses, 

93  Generators, high  frequency 

94  Grid  choppers,  rotary 


Lilators,  composition 
ulatora,  fibre 
ulatora,  high  voltage 
ulatora,  cloth 
ulatora,  glass 
Lilators,  hard  rubber 
ulatora,  porcelain 
is,  soldering 


95  Grid  leak  holders 
I  96  Grid,  transmitting  leak* 

97  Grid  leaks,  tube 
!  98  Grid  leaks,  variable 
I  99  Grinders,  electric 

100  Ground  clamp* 

101  Ground  rods 

102  Handles,  switch 

103  Head  band* 

104  Head  phone* 

105  Head  sets 

106  Honeycomb  coil  adapters 

107  Hook  ups 

108  Horns,  composition 

109  Horns,  fibre 

110  Horns,  mache 

111  Horns,  metal 

112  Homs,  wooden 

113  Hydrometers 

114  Indicators,  polarity 

115  Inductances,  C.  W. 

116  Insulation,  molded 

117  Insulation  material 

118  In 

119  In 

120  In 

121  In 

122  In 

123  In 

124  In 

125  In 

126  In 

127  Ja 

128  Filament  control 

129  Jars,  battery 

130  Keys,  transmitting 

131  Knobs 

132  Knock-down  panel  unit* 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arrester* 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  unit* 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instrument* 

142  Megohmeters 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheet* 

147  Milliammeters 

148  Minerals 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,       condenser 
leak 

153  Mounting*,  end 

154  Mountings,  grid  leak 

155  Mounting*,  honeycomb 
coil 

156  Mounting*,     Inductance 
switch 

157  Name  plate* 

158  Neutrodyne  set  part* 

159  Nuts 

160  Oh  meters 

161  Oscillators 

162  Panel  cutting  and  drilling 

163  Panels,     drilled     and     un- 
billed 

164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  soldering 

168  Patent  attorneys 

169  Phone  connector*,  multi- 
ple 

170  Phonograph  adapter* 

171  Plates,  condenser 

172  Plugs,  coil 

173  Plugs,  telephone 

174  Pointers,  dial  and  knob 

175  Poles,  aerial 

176  Potentiometers 

177  Punching  machine* 

178  Reinartz  set  part* 

179  Regenerative  set  parts 

180  Receiver  cap* 

181  Rectifiers,  battery 

182  Resistance  leak* 

183  Resistance  units 

184  Rheostat  bases 

185  Rheostat  strip* 


186  Rheostat*,  automatic 

187  Rheostats,  battery 

188  Rheostats,  dial 

189  Rheostats,  filament 

190  Rheostats,     potentiometer 

191  Rheostats,  power 

192  Rheostats,  vernier 

193  Rods,  ground 

194  Rotors 

195  Scrapers,  wire 

196  Screwdrivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving — cabinet 

200  Sets,  receivings-crystal 

201  Sets,      receiving — knock- 
down 

202  Sets,      receiving  —  Neutro- 
dyne 

203  Sets,  receiving — portable 

204  Sets,    receiving — radio   fre- 
quency 

.205  Sets,     receiving— reflex 

206  Sets,    receiving — regenera- 
tive 

207  Sets,    receiving — Reinartz 

208  Sets,  receiving — sectional 

209  Sets,  receiving — shortwave 

210  Seta,     receiving — auper-re- 
generative 

211  Sets,  transmitting 

212  Slate 

213  Shellac 

214  Sliders 

215  Socket  adapter* 

216  Sockets. 

217  Solder 

218  Soldering  irons,  electric 

219  Soldering  paste 

220  Solder  flux 

221  Solder  salts 

222  Solder  solution 

223  Spaghetti  tubing 

224  Spark  coils 

225  Spark  gaps 

226  Stamping* 

227  Statora 

228  Stop  points 

229  Switch  arm* 

230  Switch  levers 

231  Switch  points 

232  Switch  stops 

233  Switchea,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switchea,  ground 

237  Switchea,  inductance 

238  Switches,  panel 

239  Switches,  single  and  dou- 
ble throw 

240  Tone  wheels 

241  Towers,  aerial 

242  Transformers,     audio    fre- 
quency 

243  Transformers,  filament 

244  Transformers,  modulation 

245  Transformers,  power 

246  Transformers,  push-pull 

247  Transformers,     radio     fre- 
quency 

248  Transformers,  variable 

249  Transmitters 

250  Tubes,  vaccuum — peanu 


251   Tubei 

— two   ele— 

2S2  Tube,,  vacuum- 

-thxee  ele- 

253  Tune 

254  Vario 

255  Vario 

ouplers,  mo]  ded 

256  Vario 

ooden 

257  Vario 

-netera,  hard  rubber 

258  Vario 

>Ided 

259  Vario 

■netera,  wooden 

260  Vami 

sh,  insulating 

261  Voltrr 

etera 

262  Wach 

263  Wave 

meter. 

264  Wave 

trap. 

265  Wire, 

aerial 

266  Wire, 

braided  ar 

267  Wire, 

copper 

268  Wire, 

269  Wire, 

Litz 

270  Wire, 

magnet 

271   Wire, 

platinum 

272  Wire, 

tungsten 

RADIO  AGE  BUYERS*  SERVICE,  BOO  N.  Dearborn  St-,  Chicago,  III. 

Please  see  that  I  am  supplied  with  buying  specifications  and  prices  on  the  articles  numbered  herewith: 


I      I       I      I      1      I 


I  am  a —  Q  Dealer            ^j  Jobber         Q    Mfgrs.'  Rep.          □    Manufacturer 
Firm     [If  identified  with  Radio  industry]  _ - m 

My   Nam*   

Address    , 


City   ._ __ ,    State   ._ 


The  Far  West  Gets  Its 
Radio  Thrill 

Far  back  in  the  days  of  the  gold  rush 
in  Nevada — Tuscarora,  became  one  of  the 
most  prominent  settlements  in  this  vast 
area  of  the  unexplored  western  frontier. 
The  bright  metal  manifested  itself  in 
greater  quantities  and  with  less  difficulty 
to  obtain  than  in  almost  any  section 
during  these  feverish  days  of  prospect- 
ing, and  many  brought  back  wealth 
which  can  be  traced  today  to  represent 
the  beginning  of  some  of  America's 
wealthiest  families. 

No  greater  excitement  and  common 
law  ruled  a  community  more  true  to  the 
wildest  days  of  the  western  frontier,  than 
picturesque  Tuscarora — and,  these  same 
old  surroundings  stand  today  as  then, 
except  for  its  quiet  populace — doubtless 
the  fringe  of  pioneers  of  those  "gold 
days"  who  had  passed  down  from  one 
generation  to  another. 

WJAZ — The  Zenith  portable  broad- 
casting truck,  touring  to  the  western 
coast  on  experimental  broadcasting  in 
locations  which  have  baffled  radio  engi- 
neers, after  having  experimented  in 
broadcasting  from  Pike's  Peak,  began 
their  long  journey  to  Nevada  and  over 
the  Rockies  when  they  stopped  at  Tus- 
carora. Very  few  Tuscarorans  have  ever 
had  the  opportunity  to  see  much  of  this 
day's  modern  invention,  and  as  WJAZ's 
radio  transmitting  apparatus,  mounted 
on  a  motor  truck  stopped  for  the  day — 
Tuscarora  awakened  from  its  peaceful 
daily  routine  and  again  "came  out" 
with  that  same  excitement  and  gala 
front  as  of  those  bygone  days. 

Placer  miner  Lee  Wah,  one  of  the  few 
remaining  Chinamen  of  the  1500  Chinese 
laborers  brought  to  Tuscarora  more 
than  65  years  ago  to  build  the  Central 
Pacific  Railway,  after  much  explanation 
and  assurances,  finally  appeared  before 
the  "Mike"  with  his  original  Chinese 
cymbals,  gong  and  drums  which  are  over 
100  years  old  and  rendered  selections 
which  the  WJAZ  portable  station  broad- 
cast on  the  air  to  the  public  far  out  and 
beyond. 

Lee  Wah  displayed  suspicious  toler- 
ance while  performing  before  the  micro- 
phone, believing  the  entire  procedure  to 
be  a  huge  joke,  and  fell  in  with  the  occa- 
sion as  purely  a  matter  of  humor  and  to 
be  a  good  fellow.  But  when  the  camera- 
man pointed  their  outfits  his  way,  Lee 
Wah  ran  in  great  panic  for  cover.  The 
bull's  eye  lenses  to  the  Chinaman,  were 
no  different  from  any  regulation  frontier 
45  Colt's  pistol  of  the  days  when  Lee, 
(with  all  of  the  early  settlers),  came  in  to 
make  his  stipend  as  a  laundryman. 


Neat  Pliers  Made  by 
Schollhorn 

A  very  handy  and  effective  radio  plier 
is  made  by  The  William  Schollhorn 
Company,  New  Haven,  Conn.  The  pliers 
are  made  of  stamped  steel,  very  strong 
and  sturdy.  They  are  specially  suitable 
for  turning  eyelets  of  various  sizes  in  bus 
bar  wire.  Between  the  jaws  just  above 
the  square  recess  is  a  flat  vise-like  surface 
to  be  used  to  flatten  out  the  eyelet 
after  it  has  been  turned.  Below  the 
recess  is  a  sharp  pair  of  bus  bar  cutters. 
These  pliers  have  the  advantage  of  being 
large  enough  to  afford  a  good  grip  with- 
out being  excessively  heavy. 


*     Tested  and  Approved  by  RADIO   AGE     * 


Hookups  That  Will  Always 
Be  Up-To-Date! 


What  You  Get : 

The   RADIO   AGE 

ANNUAL  for  1925  is 
brim  full  of  hookups 
and  "how-to-do-it11 
articles.  In  addition 
to  the  array  of  con- 
structional set  arti- 
cles, you  will  find  in- 
structions for  build- 
ing wave  traps,  bat- 
tery chargers,  am- 
plifiers, loud  speak- 
ers, etc.  And  to  top 
it  all  you'll  find  the 
big  32-page  blue- 
print section  con- 
taining the  prize 
hookups  for  1924  and 
1925!  Real  blue- 
prints to  work  by! 
Each  blueprint  is 
worth  the  cost  of 
the  book!  120  pages 
of  features  in  all! 


You  may  try  to  save  money  on  radio  parts — 
you  may  content  yourself  with  a  mediocre,  care- 
lessly-planned radio  set,  but  after  all  is  said  and 
done  and  the  results  given  the  acid  test,  you  will 
find  there  is  no  substitute  for  a  good  radio 
hookup. 

In  choosing  the  hookup  for  your  needs  this 
Fall — the  set  that  will  penetrate  the  strong 
stations  and  bring  in  pleasing  and  clear  DX,  you 
must  get  the  absolute  best  or  you  will  regret 
your  choice  in  the  end,  when  you  will  be  forced 
to  dismantle  the  '  'just-as-good1 '  hookup  and 
make  the  real  thing. 

The  RADIO  AGE  ANNUAL  for  1925  contains 
nothing  but  tested  hookups;  circuits  that  have 
emerged  with  flying  colors  from  the  most  strin- 
gent tests  radio  engineers  could  impose.  The 
ANNUAL  does  not  contain  a  hookup  that  will 
not  please  you  in  every  way  and  be  just  as  good  a 
year  from  now  as  it  is  today. 

Before  beginning  your  new  radio  season,  get 
the  ANNUAL  for  1925  and  take  your  pick.  You 
can't  go  wrong.  Only  a  few  hundred  ANNUALS 
left,  at  a  dollar  a  copy.    Get  yours  now! 


$1.00  a  RADIO  AGE  ANNUAL  $1.00  a 

Copy  FOR  1925  Copy 

Some  of  the  Features 


How  to  read  and  understand  hookups. 

How  to  understand  radio  phenomena. 

Building  your  first  simple  set. 

How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set. 

How  to  amplify  any  kind  of  set. 

Making  a  reflex  set. 

Building  your  first  Reinartz  set. 

The  renowned  Baby  Heterodyne  No.  1. 

Adding  audio  and  radio  stages  to  the  Baby  Het. 

How  to  make  a  battery  charger. 

How  to  make  a  loud  speaker. 

RADIO    AGE    ANNUAL    BLUEPRINT    SECTION    with    such 

popular    hookups    as    the    aperiodic    variometer,    loop    sets. 


feedback  receivers,  neutrodynes,  re:lex  hookups.  Baby  Het  No. 
2,  a  Wonder  Super-Het,  and  others. 

How  to  get  rid  of  interference. 

How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super-heterodyne  for  the  super  experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

AND  MANY  OTHER  UP-TO-THE-MINUTE  HOOKUPS  AND 
ARTICLES. 


RADIO  AGE  ANNUAL  COUPON 
RADIO  AGE,  INC., 
500  North  Dearborn  St.,   Chicago,  III. 

Gentlemen:       I  want  to  be  a  proud  owner  of    the  RADIO  AGE  ANNUAL  FOR  1925.     Enclosed  find 
$  1 .00.      I  f  I  am  not  satisfied  with  the  ANNUAL  I  will  return  it  within  five  days  and  you  will  refund  my  dollar 

Name. _ _ _ __ _ 


Address  „_. 
City 

10-25 


State.. 


"as  Good  at 

Zenith 


T  WANT  a  radio  set  which  will 
*■  give  me  the  same  true  quality 
of  tone  —  the  same  selectivity  — 
the  same  volume  without  distor- 
tion —  the  same  long  distance 
range  as  Zenith."  That  is  the  ex- 
pressed desire  of  thousands  and 
thousands  of  radio  enthusiasts. 

The  reason  for  their  ambition  is 
simply  this:  Zenith  radio  sets  are 
never  offered  to  the  public  until 
all  laboratory  experiments  have 
been  carried  to  a  satisfactory  con- 
clusion —  until  in  side-by-side  tests 
with  other  radio  sets  Zenith  suprem- 
acy  has  been  completely  demon' 
strated. 

Zenith  radio  sets  will  never  be 
produced  on  a  quantity  basis  at 
the  sacrifice  of  quality. 

But  — which  is  better:  to  be  dis- 
tinguished merely  for  volume  of 
production— or  to  he  distinguished 
for  a  degree  of  excellence  so  high 
that  it  sets  the  standard  through- 
out the  industry?  Ask  your  nearest 
Zenith  dealer  for  a  demonstration. 

ZENITH  RADIO  CORPORATION 
Straus  Building,  Chicago 


Again  Commander  Donald 
B.  MacMillan  has  chosen 
Zenith  exclusively  for  his 
expedition  to  the  Arctic. 
When  human  lives  may  de- 
pend upon  the  reliability 
of  radio  performance,  only 
one  reason  can  explain  his 
choice:  Zenith  has  proved 
to  he  the  best  obtainable, 
at  any  price. 


Super-Zeniths  are  priced  at  from  $240  to  $2,000. 

Each  instrument  is  sold  under  a  quality  guarantee. 

Above  is  shown  the  De  Luxe  Italian  model. 


►LONG    DISTANCE- 

TRADE     MARK     REG. 


Costs  More  — but  Does  More! 


*     Tested  and  Approved  by  RADIO  AGE     * 


Blueprint  Section  Every  Month 


>/^ 


AEET  YOUR  BROADCAST  FAVORITE 


FACTS 


THE  "WHY  OF  THE  SIX" 

as    described  in  Radio  Broadcast  of    November 
and  December 

SELECTIVITY  is  such  that  out  of  town  stations 
may  be  brought  to  Chicago  through  twelve  powerful 
local  stations.  Selectivity  can  be  regulated  at  will, 
from  a  degree  satisfactory  for  ordinary  reception, 
up  to  the  surprising  limit  where  side-bands  are  cul . 
SENSITIVITY  is  so  great  that  nothing  will  sur- 
pass the  "Six"  except  special  laboratory-build 
super-heterodynes.  Either  coast  may  be  brought 
in  to  Chicago  during  the  summer  months  on  a  small 
antenna — in  many  cases  on  a  loop. 
FLEXIBILITY  permits  the  use  of  antenna  or 
loop  with  either  detector,  one  or  bcth  stages  of 
radio  frequency  amplification.  Interchangeable 
R.  F.  Transformers,  with  adjustable  antenna  coup- 
ler, permit  operation  on  all  waves  from  50  to  550 — 
or  higher  if  desired. 

VOLUME  is  so  great  as  to  paralyze  any  but  the 
best  loud-speakers.  Yet  it  may  be  adjusted  to  any 
degree  by  a  single  knob. 

QUALITY  cannot  be  excelled  due  to  resistance 
coupled  amplification.  It  is  the  only  receiver  that 
will  bring  real  appreciation  of  "cone"  speakers. 
CIRCUIT  consists  of  two  stages  of  R.  F.  amplifi- 
cation with  special  oscillation  control  uniformly 
effective  at  all  wavelengths,  grid-biased  detector 
and  three  stage  resistance  coupled  audio  amplifier. 
EASE  OF  CONTROL  allows  use  of  one,  two  or 
three  dials  at  will. 

TUBES  may  be  either  dry  cell  or  storage  battery, 
with  UV201-A*s  recommended.  ''B"  Battery 
Consumption  at  135  volts  is  below  10  miliamperes — 
less  than  once-third  that  of  other  six- tube  receivers. 
ASSEMBLY  requires  but  a  few  hours,  using  only 
parts  supplied  in  kit. 


^       Mail  this  Coupon 

Silver-Marshall,    Inc.,    Chicago,    111. 

Gentlemen:    Please  send  me 

A — Complete   building   data  on  the  Silver  ' 

for  which  I  am  enclosing  50c. 
B — Descriptive  circulars  on  S-M  Products. 


Name I 

i 


BOOMERANG  CRITICISM 

The  Silver  Six  is  at  once  the  most  satisfactory  and  the  most  unusual 
broadcast  receiver  ever  devised.  It  is  the  first  practical  receiver  with 
Sensitivity,  Selectivity  and  Tonal  Quality  which  cannot  be  surpassed. 
This  can  only  be  understood  by  a  careful  study  of  the  receiver's  charac- 
teristics as  analyzed  under  "FACTS." 

The  Silver  Six  was  put  through  its  paces  for  a  prominent  Editor, 
an  Engineer  and  an  Executive  just  after  it  was  perfected.  How 
did  they  react?  The  Editor  asked  to  have  the  tuning  broadened 
The  Engineer  was  astonished  at  the  uncanny  ability  to  bring  in  DX 
Stations  in  daylight  .  .  .  The  Executive  objected  to  the  intensity 
with  which  notes  low  on  the  musical  scale  were  reproduced.  Why 
did  these  men  react  this  way?  Simply  because  the  Silver  Six  was  not 
"just  another  receiver"  of  merit  easily  recognized  in  comparison  with 
existing  standards  .  .  .  But  because  it  was  an  accomplishment 
so  far  in  advance  of  the  commonplace  that  these  three  authorities  had 
to  revise  their  standards  in  order  to  appreciate  ideal  performance — ■ 
not  merely  in  theory — but  when  the  "Six"  actually  demonstrated  it  to 
their  amazed  senses. 

These  men  were  unable  to  demand  and  the  "six"  fail  to  produce.  Se- 
lectivity was  at  their  command — ease  of  control  theirs  for  the  ask- 
ing— one,  two  or  three  dials  as  preferred — volume  adjustable  by  a 
single  knob  from  a  whisper  to  a  roar  without  a  discordant  note — ■ 
rather  with  a  perfect  harmony  that  enthralled  the  listeners. 

What  Was  Their  Verdict?  Unqualified  Approval!  Why?  Because 
Seeing  Is  Believing. 

Type  600  Kit  including  all  parts  necessary  to  build  (J'C'J  f\f\ 
the  complete   "Six" «pOO.UU 

Type  610  Kit,  essentials  only,  including  3   condensers 
3   inductances   and  3  inductance  sockets. 


;  $27.75 


See  S-M  Products  at  Your  Dealers 

Silver-MarshalUnc. 

114  South  Wabash  Avenue 
CHICAGO 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour  1 


This  Catalogue 

represents  the 

world's  greatest 

radio  store 


Ward's  New  Radio  Catalogue 

Is  Yours  Free 


Where  you  buy  Radio  is  equally  as  im- 
portant as  the  set  you  buy. 

Send  to  Radio  Headquarters  for  the 
most  complete  Catalogue  of  the  season. 
See  for  yourself  what  is  new  in  Radio  and 
what  has  been  actually  tested  and  ap- 
proved. 

See  for  yourself  what  low  prices  can  be 
-made  on  Radio  when  it  is  sold  without 
the  usual  "Radio  profits." 

A  Complete  Radio  Manual 

This  new  52  page  Radio  Catalogue  shows 
everything  in  parts,  batteries,  cabinets, 
contains  a  list  of  stations,  a  radio  log  for 
recording  stations.  It  shows  the  best  of 
the  new  sets.  One  tube  sets  that  give 
amazing  results.  Five  tube  sets  with  a 
single  dial  to  turn.     Think  of  tuning  in 

•&    Me  ESTABLISHED  1872   -W-ETTT  -0      r»nrfni 

MontgomeiyWard  €?Cq 

The  Oldest  Mail  Order  House  is  Today  the  Most  Progressive 

Baltimore    Chicago    Kansas  City    St.  Paul    Portland,  Ore.    Oakland,  Calif.     Ft.  Worth 


one  station  after  another  by  turning  a 
single  dial! 

Every  price  quoted  means  a  big  saving  to 
you.  Everything  offered  is  tested  by  our  own 
Radio  Experts;  in  fact,  the  best  experts  com- 
piled this  Catalogue  for  you. 

Write  for  this  free  52  Page  Book.  It  is  yours 
Free. 

Our  53  Year  Old  Policy 

For  53  years  we  have  sold  only  quality  mer- 
chandise under  a  Golden  Rule  Policy.  You 
can  rely  absolutely  upon  the  quality  of  every- 
thing shown  in  this  Radio  Catalogue. 


To  Montgomery  Ward  &  Co.  Dept.  18-R 
Baltimore       Chicago       Kansas  City       St.  Paul 
Portland,  Ore.        Oakland,  CalH.       Fort  Worth 

(Mail  this  coupon  to  our  house  nearest  you.) 
Please  mail  my  free  copy  of  Montgomery 
Ward's  New  Radio  Catalogue. 

Name 

Local  address 

Post  Office 

State 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 

WITH  WHICH  IS  COMBINED  RADIO  TOPICS 


Volume  4 


November,  1925 


Number  11 


CONTENTS 

Cover  Design  by  Anker  P.  Mehlum 

A  Super  Het  without  Intermediate  Stages.. 7 

By  Roscoe  Bundy 
Riding  the  Short  Waves. 11 

By  Armstrong  Perry 

Directing  the  Air  Mail  By  Radio 13 

By  S.  R.  Winters 

A  Windless,  Pipeless  Pipe  Organ.... 15 

By  J.   C.  Jensen 
A  New  Low  Loss  Receiver 17 

By  H.  Frank  Hopkins 

Magnetic  Theory  of  Radio  Transmission 21 

By    Beecher  I.  Sheridan 

On  Inductive  Radio  Interference 22 

How  to  Make  an  Efficient  Low-Wave  Transmitter..23 

By    Brainard    Foote 
RADIO  AGE  "What  the  Broadcasters  are  Doing" 

Studio-Land   Feature  Section 25-32 

RADIO  AGE   BLUEPRINT  Section— Adding 

Radio    Frequency   Stages 33-40 

By  John  B.  Rathbun 

Late  Models  at  the  Chicago  Radio  Show.. 42 

Pickups  and  Hookups  by  our  Readers.. 43 

Corrected  List  of  Broadcasting  Stations  ....66-68-70 


Radio  Age  is  published  monthly  by  RADIO  AGE,  Inc. 
Member:      Audit  Bureau  of  Circulations. 


Publication    Office,     Mount     Morris,     111. 

Address  all  communications  to  RADIO  AGE,  INC. 
Executive,  Editorial  and  Advertising  Offices 
500    N.     Dearborn    Street,     Chicago,     111. 


Frederick  A.  Smith,   Editor 
Frank  D.  Pearne,   Technical  Editor 
M.   B.   Smith,   Business   Manager 

Advertising    Director 
HARRY  A.  ACKERBURG 

500  N.  Dearborn  St.,  Chicago,  III. 


Eastern     Representative 
DAVIDSON  &  HEVEY,   17  West  42nd  St.,   New  York  City 

Pacific    Coast    Representative 
V.  M.   DEPUTY  &  ASSOCIATES,  515  F.  W.   Braun 
Los   Angeles,    Cal. 


Bldg., 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 
preceding  date   of  issue 

Vol.  4,  No.  11.     Issued  monthly.    Subscription  price  S2.50  a  year.  November,  1925. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris.  Illinois,  under  the 

Act  of  March  3.   1879. 


Corvriaht.  lets,  In  RADIO  AGS.  Inc. 


A  Chat  With 
the  Editor 


EDITORS,  engineers  and  manu- 
facturers have  combined  their 
efforts  toward  making  "The 
Radio  Age  Model  Receiver"  a  truly 
valuable  aid  to  the  home  set-maker. 
The  description  of  the  circuit,  with 
drawings,  photographs  and  blue- 
prints, will  be  published  in  the 
December  issue.  We  are  giving 
the  circuit  a  name  which  clearly 
shows  that  back  of  this  outfit  is  the 
indorsement  of  our  engineers  and 
editors.  We  do  not  claim  this 
circuit  is  a  departure  from  present 
approved  lines  of  design  and  con- 
struction. We  do  not  claim  that 
it  involves  any  radical  improve- 
ments. We  merely  assert  our  con- 
fident belief  that  this  December 
feature  will  be  the  best  illustrated 
how-to-make  article  this  magazine 
has  ever  published. 

All  parts  used  in  the  construc- 
tion of  this  set  will  be  listed  under 
their  trade  names.  This,  in  itself, 
is  a  departure  for  Radio  Age.  Our 
policy  heretofore  has  been  to  let 
the  reader  make  his  own  selections 
of  apparatus  and  accessories.  In 
this  feature  article,  however,  we 
are  going  to  try  to  make  the  in- 
structions so  complete  that  no 
reader  will  have  to  ask  a  single 
question  further  after  he  has  read 
the  directions. 

Realizing  that  in  choosing  good 
parts  for  a  five-tube-tuned  radio 
frequency  receiver,  such  as  this 
set,  it  will  be  impossible  to  include 
all  the  really  good  parts  which 
would  give  satisfaction  for  a  given 
purpose,  it  is  our  purpose  to  follow 
the  original  article  with  others,  one 
each  month,  in  which  there  will 
be  changes  in  various  details  of 
the  circuit  and  in  which  the  list  of 
parts  again  will  contain  trade 
names,  probably  quite  a  different 
list  in  a  majority  of  its  items  from 
the   December  suggestions. 

Tuned  radio  frequency  is  popu- 
lar now.  We  suggest  that  set- 
makers  make  sure  of  getting  the 
December  issue  and  follow  the 
series  carefully. 


Editor  of  RADIO  AGE 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


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The  Magazine  of  the  Hour 


BE 


CHICAGO'S  experience  with  silent  Monday  nights 
is  one  which  supplies  plenty  of  evidence  that  the 
radio  public  is  really  the  boss  of  broadcasting- 
During  the  recent  summer  a  dozen  Chicago  stations 
were  on  the  air  on  Monday  nights,  in  spite  of  the  fact 
that  that  night  was  theoretically  silent.  The  mayor's 
radio  commission  and  the  broadcasters  had  attempted 
to  get  together  on  a  plan  which  would  make  Monday 
night  silent  in  fact  as  well  as  in  theory.  But  several 
of  the  broadcasters  refused  to  abandon  their  place  at 
the  microphone  on  those  nights  and  as  a  result  other 
broadcasters  announced  that  they  also  would  broad- 
cast on  Monday  nights. 

We  do  not  know  that  a  silent  night  for  Chicago 
stations  is  an  unmixed  blessing.  We  suspect  that 
there  are  thousands  of  listeners  in  the  great  middle 
west  city  who  would  prefer  to  have  Chicago  stations 
broadcast  seven  nights  the  waek.  This  is  true  chiefly 
because  there  are  many  fans  who  do  not  aspire  to 
get  distance  for  its  own  sake.  Many  others  have 
receiving  equipment  that  is  not  designed  for  distance 
work. 

However,  there  are  tens  of  thousands  of  fans  in  the 
Chicago  district  who  prefer  to  have  Monday  nights  for 
travelling  from  state  to  state  and  from  station  to 
station.  It  was  not  realized  how  numerous  these  fans 
were  until  they  became  articulate  through  the  Broad- 
cast Listeners'  Association  of  America. 

The  B.  L.  A.,  which  announces  it  has  branches  in 
twenty-two  states,  organized  a  listeners'  strike.  Mem- 
bers of  the  association  were  urged  to  write  to  the 
broadcasters  who  did  not  observe  silence  on  Monday 
nights  and  tell  the  station  owners  that  the  individual 
signing  the  letter  would  not  listen  in  on  the  offending 
station  at  any  time  unless  the  station  became  silent  on 
Monday  nights.  How  many  of  these  protests  were 
received  by  broadcasters  is  not  known.  There  must 
have  been  an  impressive  number  judging  from  the 
immediate  results.  One  after  another  the  stations 
shut  off  their  generators  on  Monday  nights,  put  a 
dust  cloth  over  the  microphones  and  turned  out  the 
lights  in  the  studios.  Charles  E.  Erbstein,  owner  of 
WTAS,  Elgin,  111.,  was  the  latest  to  announce  that  he 
will  be  silent  on  Monday  nights.  That  leaves  only  one 
station  on  the  air  in  the  Chicago  district  during  the 
forbidden  period. 

It  really  appears  that  the  fans  accomplished  an 
object  which  the  mayor  of  Chicago,  several  of  his 
aldermen  and  representatives  of  stations  had  failed  to 
do.     Truly  the  radio  fan  is  a  power  in  the  land.     It 


only  goes  to  prove  the  ancient  impression  that  a  good 
listener  is  about  as  great  an  institution  as  a  good 
broadcaster. 

CHARLES  E.  ERBSTEIN,  owner  of  stations 
WTAS  and  WCEE  on  the  hill  top  near  Elgin, 
111.,  is  the  stormy  petrel  of  radio  broadcasting.  He  is 
unique.  There  have  been  reports  that  his  stations 
were  to  be  taken  over  by  the  owners  of  the'  Chicago 
Tribune  and  negotiations  may  be  completed  before 
this  gets  into  type.  If  the  sale  of  his  stations  means 
that  Charlie  Erbstein  is  not  to  continue  regularly  as  an 
announcer  the  news  will  cause  a  pang  of  regret  in  the 
hearts  of  literally  millions  of  listening  fans. 

Erbstein  is  an  extremely  successful  lawyer.  He  is 
a  gifted  pleader  before  juries.  He  is  quick  witted; 
he  is  a  satirist  of  parts;  he  is  a  master  of  repartee. 
He  has  courage  to  say  what  he  chooses  to  say.  He 
follows  no  rule  of  ethics  or  conduct  in  a  station  studio 
unless  he  thinks  that  rule  should  apply. 

The  lawyer-announcer-broadcaster  picked  up  his 
vast  enthusiasm  for  radio  several  years  ago,  before 
broadcasting  was  born,  He  found  that  experimenting 
with  radio  transmission  and  reception  devices  was  a 
fascinating  relaxation  for  him  and  he  spent  much  of 
his  time  during  long  winter  evenings  making  his  own 
stuff,  winding  coils,  testing  resistances,  measuring 
capacities  and  soldering  joints.  Soon  after  broadcast- 
ing arrived  Mr.  Erbstein  spent  a  small  fortune  on 
broadcasting  equipment  and  erected  a  station  that  is 
easily  one  of  the  best  in  the  United  States. 

Ever  since  he  started  Mr.  Erbstein  has  been  making 
the  country  listen.  Fans  have  called  him  eccentric, 
but  he  is  not.  He  is  simply  natural.  He  recites 
"The  Face  on  the  Barroom  Floor"  and  "The  Shooting 
of  Dan  McGrew."  He  quotes  James  Whitcomb  Riley 
while  "The  Boss'  Own  Orchestra"  plays  creepy,  weepy 
music.  He  calls  for  contributions  for  a  relief  fund  for 
the  victims  of  a  devastating  tornado  and  with  tears 
glistening  in  his  eyes  and  emotion  choking  his  voice  he 
acknowledges  the  checks  that  pour  in.  He  talks 
politics,  religion,  international  economy.  He  sings 
"You  Can't  Fool  an  Old  Horse  Fly"  and  forgets  that 
he  is  working  fifteen  hours  out  of  twenty-four.  In 
distant  parts  of  the  country  they  have  acquired  the 
habit  of  listening  in  for  Charlie.  He  pays  the  bills 
himself  and  they  are  large  bills,  frequent  and  contin- 
uous bills. 

If  broadcasting  loses  the  Erbstein  drollery  and 
philosophy  it  loses  a  studio  character  whose  like  is  not 
to    be    found. 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


Bennington 
Tube  Socket 


Mason  Z  8s  T  Jr. 
Detector 


Saal 
Soft  Speaker 


Pacent  Knob 


Pathe  Dial 


Bakelite  is  an  exclusive 
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used  only  on  products 
made  from  materials 
manufactured  by  the 
Bale elite  Corporation. 
It  is  the  only  material 
which  may  bear  this 
famous  mark  of  excel- 
lence. 


Radio  tested  all  insulations 
and  adopted  TSakditt 

In  all  the  laboratories  of  radio  manufacturers,  in  actual 
use  in  all  climates  and  under  adverse  conditions,  Bake- 
lite  has  proven  its  superiority  for  radio  insulation. 

The  reason  for  this  dominance  of  Bakelite  in  radio  is 
easily  understood.  Its  high  insulation  value,  so  essen- 
tial to  tonal  quality,  is  unimpaired  by  time,  tempera- 
ture variations  or  by  service. 

Bakelite  is  generally  used  for  exposed  radio  parts, 
dials,  knobs,  panels  and  accessories,  because  its  color 
and  high  finish  are  permanent,  undimmed  by  exposure 
or   handling. 

The  use  of  Bakelite  in  the  set  you  buy  or  build,  will 
insure  you  against  inferior  reception  through  defective 
insulation.  It  will  pay  you  to  make  sure  that  Bakelite 
is  used  in  the  radio  set  or  parts  that  you  buy. 


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THE    MATERIAL    OF  A  THOUSAND    USES 


¥     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


<^^mm^  j^t  ^mj  Unlike  Some  Music 

*  ^^ OZARKA  SERVICE 
Satisfies  Every  Owner — 

A  Few  More 
Men  areNeeded 


IN  radio,  when  one  selection  does  not  please,  you  simply  tune  it 
out  and  pick  up  another  broadcasting  station.  If  it  is  a  matter 
of  unsatisfactory  volume  or  tone  in  your  instrument  then  it  becomes 
an  entirely  different  matter. 


You  have  certain  very  definite  ideas 
in  mind  as  to  what  you  want  your 
radio  to  do.  Will  you  allow  us  to  make 
a  few  suggestions  regarding  a  plan 
whereby  you  can  settle  the  radio 
question? 

Select  the  instruments  which  you 
think  might  answer.  Have  a  demon- 
strating instrument  brought  to  your 
home.  Let  each  salesman,  in  turn, 
make  the  necessary  battery  connec- 
tions. Let  him  tell  you  how  to  operate 
it  but  do  all  the  tuning  yourself. 

You'll  buy  the  instrument  then, 
based  on  your  own  operation.  You'll 
size  up  each  one  for 

— ease  of  tuning 
— distance  received 
— volume 
— tone 
— selectivity 
— price. 

There  still  remains  one  very  impor- 
tant question  to  settle — the  matter  of 
service.  No  matter  what  anyone  tells 


you  sometimes  little  things  may  go 
wrong.  The  best  radio  salesman  often 
knows  nothing  of  correcting  radio 
troubles — -satisfy  yourself. 

Our  Ozarka  representative  in  your 
community  will  gladly  put  an  Ozarka 
in  your  home  for  such  a  test.  More 
than  this,  you  will  find  that  he  is  a 
thoroughly  trained  mechanic  on  our 
instrument.  He  has  gone  through  a 
complete  course  of  study  under  Ozar- 
ka Engineers,  the  men  who  designed 
and  perfected  the  Ozarka. 

3187  such  men  today  can  correct 
any  trouble  which  may  ever  occur  on 
any  Ozarka  instrument — more  men 
are  being  factory  trained  daily.  You 
wouldn't  buy  an  instrument  blindly — 
then  don't  buy  service  the  same  way. 
Any  radio  instrument  is  only  as 
satisfactory  as  the  quality  of  service 
behind  it. 

Our  Book  No.  200  shows  the  full 
Ozarka  line  from  $75.00  to  $197.50, 
complete  with  all  accessories. 


In  a  great  many  counties  we  have  the 
man  we  want.  He  is  rapidly  building  up  a 
permanent  and  profitable  business  of  his 
own  because  he  has  an  instrument  that  will 
more  than  meet  all  competition.  More  than 
this,  he  is  trained  to  back  up  his  sales  with 
the  kind  of  service  that  counts. 

Many  well  established  Ozarka  representa- 
tives started  by  giving  us  only  their  spare 
time — their  evenings.  If  your  county  is  open 
you  can  do  the  same. 

The  investment  in  cash  is  very  small. 
The  investment  in  time  necessary  for  study 
is  considerable.  It  requires  patience,  but 
the  results  have  enabled  many  men  to  get 
out   of    the   salary   and    time   clock   class. 

Any  previous  sales  experience  is  helpful 
but  not  necessary.  We  can  and  will  teach 
you  how  to  sell. 

Send  for  64  Page  Book — 
_____   "The  Ozarka  Plan" 

This  book  is  entirely  too  expen- 
sive to  be  sent  out  on  postal  card 
requests.  It  will  be  sent  FREE  to 
any  man  who  mails  the  coupon 
below  and  who  is  really  anxious 
to  improve  his  condition.  Tell  us 
about  yourself  —  ask  for  Ozarka 
Plan  No.  1 00  and  don't  fail  to  give 
the  name  of  your  county. 


122  Austin  Avenue  A 
Chicago,  Illinois 


Gentlemen:  Without  obligation  send  book  "Ozarka  Instru- 
ments No.  200"  and  name  of  Ozarka  representative. 


Name 

Address City . 

County State 


//IttORPORtttfft 


122  Austin  Avenue  A 
Chicago,  Illinois 


Gentlemen :  I  am  greatly  interested  in  the  FREE  book  "The 
OzarkaPlan"No.l00,wherebyIcansellyourradioinstruments. 


Ask  the  Man  Who 
Wears  this  Button 


Address City. 

County State . . . 


*     Tested  and  Approved  by  RADIO  AGE     * 


°N  26  1925        ©C1B670347 
RADIO  AGE  for  November,  1925 


DEE 


SEE 


SHE 


SEE 


77ze  Magazine  of  the  Hour 
3BI  IBE 


1 


«^&  Magazine  gftfte  Hour 


1=1 

L 


M.  B.  Smith 

Butinemt  Manager 


A  Monthly    Publication 

Devoted  to  Practical 

Radio 


Frederick  A. 
Editor 


Smith 


J 


A  New  Super-Het  Design  that 

BANISHES  Intermediate  Stages 


ONE  of  the  most  interesting  and 
original  types  of  superheterodynes 
recently  developed  takes  full  ad- 
vantage of  the  regenerative  principle  in 
both  the  radio  frequency  and  detector 
stages,  and  the  great  amplification  thus 
attained  is  further  augmented  by  a 
cascade  coupling  between  the  two  re- 
generative elements  which  imparts  ex- 
traordinary sensitivity  and  selective  prop- 
erties to  the  circuit  without  the  neces- 
sity for  the  conventional  intermediate 
radio  stages.  As  with  the  standard  radio 
frequency  circuits,  the  radio  frequency 
stage  precedes  the  detector.  The  radio 
stage  is  heterodyned  by  an  oscillator 
and  complete  rectification  is  performed 
by  the  single  regenerative  detector  tube. 
This  is  all  there  is  to  the  proposition 
except  for  the  three  succeeding  audio 
frequency  stages. 

By  employing 
regeneration  in  the 
radio  frequency 
tube  and  detector, 
and  by  the  use  of 
a  "flat-top"  orout- 
door  antenna  in 
place  of  the  usual 
loop  aerial,  the  in- 
termediate trans- 
formers and  tubes 
are  done  away 
with,  and  the  dif- 
ficulties experien- 
ced in  properly 
matching  these 
parts  is  also  elimi- 
nated. Selectivity 
is  now  purely  a 
function  of  the 
tuning  units  com- 
bined with  the  os- 
cillator, with  no 
dependence  upon 
the  directional  pro- 
perties of  a  loop 
aerial  or  other  si- 
milar external  aux- 
iliary to  tuning. 
By  actual  test  on 
the  circuit,  it  was 
found  that  really 
distant   stations 


By  ROSCOE  BUNDY 


Copyright  1925 


No  Loop  or  Matched 
Parts  Required  in 
This  Unusual  Super 


could  be  tuned  in  perfectly  through 
strong  local  stations,  differing  in  wave- 
length by  only  a  few  meters,  and  that 
such  stations  came  in  without  the  slight- 
est suggestion  of  interference.  The 
added  complication  of  manipulating  the 
loop  during  tuning  no  longer  exists  so 
that  the  two  dials  are  really  the  only 
wavelength  adjustments  necessary. 


Q—f\—s\ 


OJ 


Hl|«k|l|l|l|l|l£ 
A  B 


A  THIRD,  but  no  less  important 
-^*-  feature  of  the  circuit  is  the  ability 
to  heterodyne  to  a  very  low  wavelength, 
much  lower  than  commonly  used  in  the 
intermediate  stages  of  other  super-hets. 
This  reduces  the  number  of  "repeat 
stations"  on  the  dials  to  a  point  where 
"repeating"  is  at  an  absolute  minimum 
with  a  corresponding  gain  in  effective 
tuning,  and  simplicity  in  operation  for 
the   novice. 

One  of  the  principal  objections  to 
the  standard  type  of  superheterodyne 
has  been  the  repeating  of  the  same 
station  at  two  or  more  dial  positions, 
and  in  the  elimination  of  this  objec- 
tionable feature  the  new  circuit  stands 
unique.  Even  strong  locals  rarely  repeat, 
while  the  duplication  of  distant  stations 
is  practically  unknown. 

The  Circuit 
Explained 

Because  of  the 
many  functions 
performed  by  each 
of  the tubes  and the 
relations  existing 
between  the  vari- 
ous stages,  it  will 
probably  be  easier 
to  explain  each 
stage  by  itself  and 
then  show  them 
completely  assem- 
bled in  their  pro- 
per relative  posi- 
tions. In  Fig.  1  we 
have  isolated  the 
first  or  radio  fre- 
quency amplifying 
stage  from  the  bal- 
ance of  the  circuit 
in  order  to  show 
how  the  regener- 
ative feature  is  at- 
tained and  howthe 
oscillator  coupling 
is  effected. 

In  many  ways, 
the  radio  fre- 
quency  stage  is 
very  similar  to  the 


RFT-I 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


inputN 


RFT-I 


Weagent  regenera- 
tive circuit  when 
the  feedback  is 
considered.  We 
have  the  aperiodic 
primary  (LI)  in 
the  antenna  cir- 
cuit and  the  secon- 
dary coil  (L2)  tun- 
ed to  wavelength 
by  the  0.0005  mf. 
variable  condenser 
(CI).  At  (tl)  is  a 
tap  which  goes  to 
(-A)  so  that  the 
portion  of  the  coil 
(TICK)  below  the 
tap  point  is  really 
the  tickler  coil  for 
obtaining  regener- 
ation. A  wire 
(wl)  connected  to 
the  plate  of  the 
radio  frequency 
tube  (Tl)  feeds 
back  the  plate  cur- 
rent to  the  tickler 
coil  through  the 
three-plate  vari- 
able regenerative 
control  condenser 
(Kl).  This  is  not 
a  very  critical  con- 
trol and  is  used  for  clearing  up  the  signals 
and  for  controlling  the  volume. 

Below  the  coil  (L2),  and  inductively 
coupled  with  it,  is  the  single  turn  pick- 
up coil  (L3)  connected  to  the  oscillator 
circuit.  All  coils  (LI),  (L2)  and  (L3) 
are  in  inductive  relation  to  one  another 
and  are  wound  solenoid  fashion  on  an 
insulating  tube.  It  is  through  (L3)  that 
the  heterodyne  effect  is  obtained  by 
impressing  the  oscillations  of  the  ex- 
ternal oscillator  tube  upon  the  in- 
coming waves.  At  (L4)  is  the  primary 
coil  of  the  radio  frequency  transformer 
or  fi'ter  (RFT-1)  through  which  the  put- 
put  of  the  tube  (Tl)  is  coupled  to  the 
following  detector  tube.  This  completes 
the  radio  frequency  circuit.  Primary 
coil  (LI)  =10  turns  of  No.  22  wire,  sec- 
ondary (L2)=46  turns  of  No.  22  wire, 
and  (L3)  =  l  turn  of  No.  22. 

Following  the  radio  frequency  cir- 
cuit is  the  detector  circuit  of  Fig.  2, 
coupled  by  means  of  the  air-core  radio 
frequency  transformer  or  filter  (RFT). 
The  primary  (L4)  carries  the  putput 
of  tube  (Tl)  as  previously  explained  and 
acts  inductively  on  the  secondary  (L5). 
As  before,  the  secondary  is  tapped  at 
(t2)  with  a  connection  to  the  (  —  A)  line, 
and  the  lower  portion  of  the  coil  (TICK) 
again  acts  as  the  tickler  coil  for  securing 
regeneration.  At  (GC)  and  (GL)  are 
the  usual  grid  condenser  and  leak  used 
with  a  detector  circuit,  but  now  variable 
condenser  is  used  for  tuning  the  system 
to  wavelength.  Coil  (L4)  =330  turns  of 
No.  26,  coil  (L5)  =90  turns,  and  (TICK) 
=  330  turns  of  same  wire. 

By  means  of  the  wire  (w2)  connected 
to  the  plate  circuit,  plate  feedback  is 
led  to  the  tickler  coil  through  the  variable 
regenerative  control  condenser  (K2). 
The  latter  is  a  very  small  condenser  of 
the  "midget"  type,  and  when  once  ad- 
justed seldom  needs  attention.  It  is 
evident    that    this    is    a    Weagent   type 


AFT-I 


K2 


LL 


ar2. 


-A 


+A 


-T-B45 


F/e.Z 


regenerative  similar  to  the  first  stage, 
except  for  the  addition  of  the  grid  con- 
denser and  leak.  With  the  two  circuits 
coupled  together,  we  have  a  cascade  re- 
generative circuit  with  its  output  con- 
nected to  the  first  audio  frequency 
transformer  (AFT-1).  Following  the 
detector  are  three  audio  stages  of  the 
usual  type  for  increasing  the  audio 
volume  of  the  detector. 

A  0.0005  fixed  condenser  (KT5)  is 
connected  across  the  coil  section  (90 
turns)  marked  (L5)  for  sharpening  the 
tuning. 

Oscillator  Circuit 

NOW  comes  the  third  and  last  ele- 
ment of  the  radio  frequency  cir- 
cuit, the  oscillator  circuit,  which  super- 
poses the  oscillations  of  an  external 
oscillator  tube  upon  the  secondary 
circuit  of  the  radio  frequency  stage. 
This  is  shown  in  detail  by  Fig.  3,  where 
the  oscillator  tube  (T3)  is  connected  to 
the  grid  coil  (L6)  and  the  plate  coil 
(L7)  in  the  usual  manner.  The  fre- 
quency of  the  oscillations  is  controlled 
by  the  second  variable  tuning  condenser 
(C2)  which  has  a  capacity  of  0.00025 
mf.  At  (K3)  is  a  1.0  mf.  fixed  bypass 
condenser. 

A  rather  unusual  link  coupling  (M) 
is  made  between  the  oscillator  circuit 
and  the  radio  frequency  secondary  by 
coils  (L3)  and  (L8).  As  before  ex- 
plained, coil  (L3)  forms  a  portion  of  the 
antenna  tuning  unit  as  shown  in  Fig.  1, 
but  the  coil  (LS)  consists  of  two  turns 
of  wire  wound  between  the  grid  and  plate 
coils  (L6)  and  (L7)  of  the  oscillator 
circuit.  This  arrangement  gives  the 
necessary  loose  coupling  between  the 
two  circuits,  and  at  the  same  time  is 
mechanically  advantageous  in  assem- 
bling the  coils  in  the  receiver.  Coils 
(L6)  and  (L7)  =28  turns  of  No.  22  wire, 
(L8)=2  turns  of  No.  22. 


Complete  As- 
sembled Circuit 

All  of  the  ele- 
mentary circuits 
are  shown  com- 
pletely assembled 
in  the  proper  rela- 
tion by  Fig.  4, 
where  they  will  be 
recognized  by  a 
close  examination. 
Indentification  is 
simplified  by  using 
the  same  letters  in 
Fig.  4  as  in  the  first 
three  small  dia- 
grams, so  that  it 
should  not  be  dif- 
ficult  for  the 
novice  to  under- 
stand the  func- 
tioning of  the  cir- 
cuit. The  three 
audio  frequency 
stages  are  shown 
behind  the  detec- 
tor  circuit,  by 
which  the  volume 
is  brought  up  to 
loudspeaker 
requirements. 

Impulses  from 
the  antenna  are 
led  to  tube  (Tl)  and  amplified  at  radio 
frequency  with  further  amplication  by 
the  regenerative  feature  already  ex- 
plained. These  waves  are  then  hetero- 
dyned by  the  oscillations  of  tube  (T3) 
coupled  to  the  radio  frequency  circuit 
through  the  Marconi  type  link  (M),  and 
the  output  of  the  radio  frequency  tube  is 
then  coupled  to  the  detector  tube  (T2). 
The  detector  rectifies  the  currents  re- 
ceived from  the  first  stage  and  develops 
the  audio  frequency  phase  so  that  the 
signals  become  audible.  Regeneration 
in  the  detector  stage  still  amplifies  the 
signal  so  that  the  total  amplification  at 
the  output  of  (T2)  is  unusually  great, 
although  only  two  tubes  are  employed. 

Only  two  wavelength  controls  are 
needed,  condensers  (CI)  and  (C2). 
Condenser  (Kl)  is  not  concerned  in  the 
wavelength  adjustment,  but  is  used  for 
controlling  the"  volume  and  for  clearing 
up  the  signals  when  excessive  regenera- 
tion tends  to  make  them  mushy.  Con- 
denser (K2)  is  seldom  touched  after 
the  set  is  once  adjusted.  Tuning  is 
surprisingly  sharp,  but  with  the  coils 
properly  adjusted,  the  two  condensers 
can  be  so  carefully  logged  and  matched 
that  little  difficulty  is  experienced  in 
picking  up  even  the  weakest  of  stations. 
Locals  go  in  and  out  completely  with  one 
division  of  dial  movement,  and  further, 
the  set  is  not  only  sharp  but  is  also  per- 
fectly selective  with  no  "fringe"  or 
hangovers"  after  the  given  wavelength 
has  been  passed. 

Some  contribution  is  made  to  the 
sensitivity  of  the  circuit  by  the  oscilla- 
tor tube  and  circuit,  but  its  principle 
function  is  added  selectivity  and  stabil- 
ity to  the  regenerative  circuits.  By  the 
two  condenser  controls  the  range  is 
from  slightly  below  200  meters  to  555 
meters  with  properly  designed  coils,  and 
throughout  this  range  the  dials  seldom 
if  ever  "repeat"  a  station  owing  to  the 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


low  wavelength  of  the  heterodyned 
waves,  made  possible  by  this  particular 
arrangement.  Impressing  the  oscillator 
waves  upon  the  first  stage  permits 
regeneration  to  be  carried  to  a  higher 
degree  than  with  the  ordinary  type  of 
regenerative  circuit,  so  that  the  oscilla- 
tor tube  indirectly  adds  further  amplifi- 
cation and  is  not  to  be  considered  as  an 
idle  tube  as  in  the  majority  of  super- 
heterodynes. It  is  possible  that  this 
stabilizing  influence  may  be  some- 
what after  the  nature  of  the  system  em- 
ployed in  the  old  time  super-regenerative 
circuit,  where  the  amplifier  is  intermit- 
tently opened  and  closed  by  the  oscilla- 
tor tube  so  that  tube  "flopping"  and 
squealing  did  not  take  place  with  the 
usual  degree  met  with  in  feed-back 
coupling. 

Audio  Amplification 

/CONNECTED  to  the  output  of  the 
detector  tube  are  the  three  cascade 
audio  frequency  stages  employing  the 
audio  tubes  (T4-  TS-  T6).  These  stages 
are  coupled  together  by  the  usual  iron- 
core  audio  frequency  transformers  (AFT- 
1),  (AFT-2)  and  (AFT-3)  which  must 
be  perfectly  matched  to  avoid  howling 
and  other  troubles  incident  to  the  use 
of  three  audio  stages.  This  audio  am- 
plification insures  more  than  ample 
volume  with  the  weakest  stations  passed 
by  the  detector  tube  and  all  broadcasting 
stations  can  be  heard  on  the  loud  speaker 
with  volume  to  spare. 

Low  ratio  audio  transformer  are  used 
with  a  ratio  of  from  2-to-l  to  3-to-l,  and 
even  with  these  low  ratios,  the  three 
stages  must  be  carefully  handled  to 
avoid  overloading  the  last  tube  (T6). 
Again,  the  transformers  must  be  per- 
fectly shielded, 
and  the  shields 
grounded,  to  pre- 
vent the  entrance 
of  radio  frequency 
strays  into  the 
audio  circuit. 

In  Fig.  4,  a  vari- 
able resistance  (r) 
isconnected  across 
the  secondary  of 
the  last  audio  fre- 
quency transfor- 
mer (AFT-3)  to 
prevent  overload- 
ing the  tube  on  the 
last  stage.  This 
resistance  is  of  the 
type  that  can  be 
varied  through  a 
range  of  from  5,- 
000  to  50,000 
ohms,  the  exact 
resistance  depend- 
ing upon  the  other 
circuit  contents. 
When  in  place,  it 
is  moved  toward 
the  low  resistance 
position  until  the 
overload  is  reduc- 
ed to  the  point 
where  howling  just 
ceases. 

Dotted  lines 
connected  to  the 
audio  transformer 


cores  at  (g-g-g)  indicate  that  the  trans- 
former casings  are  grounded  by  a  connec- 
tion running  to  the  ground  binding  post 
so  that  the  transformers  are  effectively 
shielded  from  stray  radio  frequency 
fields.  This  is  of  the  greatest  impor- 
tance to  the  proper  operation  of  the  re- 
ceiver and  the  grounds  should  be  care- 
fully made  to  avoid  distortion  and  noises. 
In  some  cases,  improvement  can  be  had 
by  connecting  a  0.0002S  mf.  fixed  con- 
denser between  (—A)  and  the  ground, 
but  in  the  majority  of  sets  a  still  better 
plan  is  to  ground  the  (—A)  line  directly 
through  a  wire  indicated  by  the  dotted 
lined  (Q)  in  the  diagram. 

In  order  to  bypass  the  radio  frequency 
currents  around  the  primary  coil  of  the 
first  audio  frequency  transformer  (AFT- 
1),  a  fixed  condenser  (K4)  will  sometimes 
be  found  advisable,  while  in  other  cases 
it  may  have  no  appreciable  effect  on  the 
operation  of  the  set.  The  exact  size 
required  can  be  best  found  by  experi- 
ment but  usually  a  0.001  mf.  or  a  0.002 
mf.  fixed  condenser  will  be  found  correct. 
This  bypass  is  not  critical.  Bypassing 
various  parts  of  the  circuit  by  means  of 
fixed  condensers  is  largely  a  matter  of 
experiment  with  the  individual  circuit, 
and  varies  with  different  types  and 
makes  of  apparatus.  What  will  be 
proper  for  one  set  of  transformers  may 
prove  inadequate  for  another  set,  and 
the  only  way  is  to  try  out  the  effects  of 
different  bypass  capacities. 

When  the  overloading  of  the  audio 
frequency  tubes  becomes  excessive,  it 
sometimes  happens  that  the  resistance 
(r)  cannot  take  care  of  the  overload 
when  located  in  the  manner  shown.  In 
such  cases,  it  will  be  well  to  try  the 
effect   of  connecting  the   variable   resis- 


tance across  the  plate  (P)  and  grid 
(G)  post  of  the  last  tube  (T6),  and  thus 
deliberately  short-circuit  the  energy 
output.  On  locals,  tremendous  volume 
is  secured  and  some  means  is  generally 
necessary  for  relieving  the  load  on  the 
tube. 

Filament  Control  System 

r  I  'WO  rheostats  are  employed  for  the 
-*-  control  of  the  filament  current.  A 
rheostat  (Rl)  controls  the  emission  of 
the  radio  frequency  tube  (Tl)  and  the 
detector  tube  (T2).  A  second  rheostat 
(R2)  controls  the  audio  frequency  tubes, 
for  the  latter  are  not  critical  and  can 
be  worked  nicely  with  a  single  rheostat. 
Experiment  has  demonstrated  the  advi- 
sability of  separate  control  of  the  first 
two  tubes  according  to  the  degree  of 
amplification  required  and  the  regenera- 
tive effect.  Regeneration  in  this  cir- 
cuit is  directly  influenced  by  the  fila- 
ment emission,  and  therefore  filament 
control  is  essential.  The  Oscillator 
tube  is  provided  with  an  amperite  con- 
trol (R3). 

A  full  90  volts  of  "B"  battery  is  used 
on  the  oscillator,  radio  frequency  and 
audio  frequency  tubes,  but  the  battery 
is  tapped  at  the  45  volt  post  for  connec- 
tion to  the  detector  tube  plate.  This 
assumes  the  use  of  the  201A  storage 
battery  tubes,  which  are  normally  used 
with  this  circuit  and  which  give  the  best 
all  around  results.  The  "199"  tubes 
can  be  used,  but  with  a  considerable 
loss  of  volume  and  range. 

There  are  some  conditions,  however, 
where  the  use  of  45  volts  on  the  first 
radio  frequency  tube  and  detector  may 
bring  in  better  distance  than  with  the 
90  volts  recommended  above,  but  it 
will  be  Well  to  try 
the  high  voltage 
first,  and  then  if 
it  is  thought  that 
the  lowerplate  vol- 
tage will  be  of  be- 
nefit, to  try  the 
45  volts. 

Tuning  the 
Circuit 

Owing  to  the 
sharpness  of  the 
tuning,  it  will  be 
necessary  to  em- 
ploy vernier  vari- 
able condensers  at 
(CI)  and  (C2), and 
to  prevent  bunch- 
ing of  the  200 
meter  stations,  the 
condensers  should 
be  of  the  straight- 
line-wavelength 
type  or  equivalent. 
These  condensers 
should  preferably 
be  of  the  recording 
vernier  order  by 
which  fractional 
parts  of  a  single 
dial  division  can 
be  accurately  re- 
corded when  the 
set  is  being  logged 
or  retuned  on  the 
samestations.  The 


10  RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


Mot/n  -Lrtcjxno 


regenerative  control- condensers  and  the 
audio  resistance  (r)  are  not  so  sharp  and 
almost  any  low  loss  condenser  will  be 
satisfactory  at  these  points. 

Rheostat  adjustments  are  not  critical 
but  should  be  turned  on  far  enough  to 
insure  that  the  tubes  are  sensitive,  say 
about  %  on  for  the  detector  rheostat 
and  nearly  full  on  for  the  audio  and  oscil- 
lator tubes.  The  position  of  the  rheostat 
knobs  varies  with  the  condition  of  the 
storage  battery,  as  well  as  the  tubes, 
and  with  a  partly  charged  battery  it 
will  be  necessary  to  turn  the  rheostats 
father  than  when  the  battery  is  fully 
charged.  It  is  not  necessary  to  use  the 
rheostats  in  tuning,  nor  is  it  desirable. 

Condenser  (K2),  used  to  control  re- 
generation in  the  detector  tube  (T2) 
is  set  slightly  below  the  point  where  it 
causes  excessive  regeneration  or  howling. 
The  closer  this  is  brought  to  the  howling 
point,  after  the  set  is  tuned  in  by  the  main 
condensers  (CI)  and  (C2),  the  greater 
will  be  the  amplification  and  volume.  It 
is  not  necessary  to  handle  this  control 
frequently,  except  when  special  con- 
ditions of  selectivity  and  sensitivity 
make  such  adjustments  necessary.  With 
the  plates  fully  meshed  and  at  full 
capacity,  the  detector  tube  (T2)  is  in 
an  oscillating  condition,  and  in  turning 
the  condenser  dial  of  (C2),  a  series  of 
clicks  will  be  heard.  Stopping  at  any 
of  these  clicks  will  show  them  to  be  whis- 
tles due  to  the  oscillations  produced  by 
the  heterodyne  oscillator,  and  when  in 
this  condition,  signals  cannot  be  heard. 
The  condenser  must  be  adjusted  so  that 
the  tube  is  just  below  this  oscillating 
point  by  moving  the  adjustment  toward 
minimum  position  gradually  until  the 
whistles  have  all  disappeared. 

With  the  condenser  (K2)  adjusted  as 
above,  the  tuning  is  performed  by  means 
of  the  dials  attached  to  (CI),  (C2)  and 
(Kl),  the  latter  being  the  regenerative 
control  for  the  radio  frequency  tube 
(Tl)  and  is  used  for  volume  control. 
The  control  (Kl)  shows  no  effect  until 
it  is  turned  nearly  to  the  point  where 
tube  (Tl)  is  thrown  into  oscillation  which 
is  evidenced  by  a  knock  or  thud  when 
the  dial  passes  the  position.  For  each 
position  of  the  two  main  condensers 
(CI)  and  (C2),  the  control  (Kl)  should 
be  turned  up  to  the  thud  point,  and  then 
turned  slightly  back  just  below  it. 

The  two  large  dials  of  (CI)  and  (C2) 
turn  practically  together,  say_  within  a 
point  or  two  on  the  dials  divisions,  for 
any  particular  wavelength  or  station 
on  that  wavelength.  To  tune  in,  set 
both  dials  at  the  same  dial  division 
number,  usually  a  low  number  in  learn- 
ing to  tune,  and  then  turn  (CI)  through 
a  few  divisions,  following  this  adjust- 
ment by  an  equal  rotation  of  dial  (C2). 
Condenser  (Kl)  should  be  kept  as  nearly 
to  the  thud  point  as  possible  during 
this  time.  Turning  the  main  dials  in 
this  way,  a  distinct  "shushing"  sound 
will  be  heard  when  the  two  dials  are  at 
the  resonant  point  for  a  given  wave- 
length, and  when  there  is  a  station  oper- 
ating on  this  wavelength,  the  carrier 
wave  of  the  station  will  be  heard  as  a 
muffled  whistle.  On  hearing  the  whistle, 
(Turn  to  page  61) 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour  11 


Riding  the  SHORT  WAVES 

BY  ARMSTRONQ  PERRY 


Amateur  Radio 
Station  9CXX, 
owned  by 
Arthur  A.  Col- 
lins of  Cedar 
Rapids,  la. 
Note  the  effici- 
ent equipment 
and  "calls 
heard"  on  the 
wall. 


Work  of  Young  Amateurs  is  Responsible 
for  Remarkable  Development  in  Short  Wave 
Work;  Many  Records  Made  by  U.  S.  Boys 


SOME  TIME  ago  it  was  discovered 
that  extremely  short  radio  waves, 
from  five  to  forty  meters  in  length, 
would  cover  distances  far  greater  than 
those  in  common  use.  Their  range  was 
discovered  to  be  practically  as  great  in 
daylight  as  in  darkness  and  static  did 
not  materially  interfere  with  their  recep- 
tion. 

Radio  amateurs  were  prompt  in  follow- 
ing up  this  discovery,  as  they  have  been 
in  developing  many  new  things  in  radio. 
One  of  the  best  known  members  of  the 
American  Radio  Relay  League,  which 
includes  most  of  the  amateur  experi- 
menters, went  as  a  Naval  Reserve  officer 
on  the  Seattle,  during  the  recent  cruise 
of  our  Pacific  fleet.  This  was  F.  H. 
Schnell,  traffic  manager.  A  Navy  officer 
reported,  after  Schnell  and  his  short 
wave  set  had  established  communication 
with  amateurs  in  many  countries,  that 
all  Schnell  had  to  do  was  to  press  the 
key  of  his  short-wave  transmitter  and 
he  would  be  heard  in  any  part  of  the 
world. 

Then  John  L.  Reinartz,  known  to  all 
amateurs  as  well  as  in  professional  radio 
circles,  went  with  the  MacMillan  Arctic 
expedition  in  the  summer  of  1925,  taking 


short-wave  apparatus.  On  the  last 
previous  Arctic  expedition  conducted 
by  MacMillan,  which  sailed  in  the  sum- 
mer of  1923  and  spent  the  winter  within 
eleven  degrees  of  the  North  Pole,  a 
prominent  amateur  named  Donald  Mix 
represented  the  American  Radio  Relay 
League  and  kept  the  expedition  in  touch 
with  the  world  most  of  the  time.  He 
was  out  of  communication  for  two  months 
at  one  time,  when  a  fifteen-year-old  boy, 
Everett  Sutton,  of  Port  Angeles,  Wash- 
ington, picked  up  his  signals  and  took 
scores  of  messages,  which  were  delivered 
per  instructions,  to  friends  and  relatives 
of  the  officers  and  crew,  to  the  press  and 
organizations  interested  in  the  expedition. 
Again  in  the  Summer  of  1925  it  was  a 
fifteen-year-old  boy,  Arthur  A.  Collins 
of  Cedar  Rapids,  Iowa,  who  succeeded 
in  keeping  in  touch  with  the  Arctic 
expedition,  using  the  shorter  wave- 
lengths, when  older  and  more  experienced 
radio  men  were  unable  to  keep  up  com- 
munication. 

Age  Is  No  Barrier 

'  I  ''HE  fact  that  in  two  successive  years 
-*-  mere  boys  should  have  been  able  to 
render    such    noteworthy    service,    indi- 


cates that  amateurs  of  any  age  have  a 
most  attractive  field  for  investigation 
in  short-wave  work.  A  visit  to  the  sta- 
tion of  Arthur  Collins,  at  Cedar  Rapids, 
showed  me  that  his  apparatus  is  simpler 
and  less  expensive  than  the  average 
radio  bug  would  think  possible.  Con- 
vincing proof  of  its  efficiency  is  shown  by 
hundreds  of  reports  from  brother  hams 
who  have  received  his  signals  in  all 
parts  of  the  United  States  and  in  Mexico, 
Hawaii,  Cuba,  Porto  Rico,  Scotland, 
England,  Belgium,  Chile,  Guam,  Tahiti, 
India,  New  Zealand  and  Australia. 

While  broadcast  listeners  are  using 
receivers  with  five  to  nine  tubes,  Collins 
hears  signals  from  distant  countries 
with  three  tubes.  He  made  his  receiver. 
The  inductance  coils  have  each  a  few 
turns  of  rather  large  wire,  insulated  by 
double  cotton  covering.  The  ends  go 
directly  to  binding  posts  on  the  panel. 
There  is  no  mounting,  knob,  dial  or 
other  device  for  changing  the  coupling. 
If  Collins  wants  to  put  the  primary 
nearer  the  secondary,  or  the  tickler 
nearer  either,  he  bends  them  over  with 
his  fingers.  The  coils  were  wound  on  a 
square  box.  When  taken  off,  the  wire 
had  a  tendency  to  uncoil.     It  was  per- 


12 


RADIO  AGE /or  November,  1925 


The  Magazine  of  the  Hour 


1 KW  (left)  and  50-watt  (right)  transmitters  of 
Arthur  A.  Collins,  9CXX,  of  Cedar  Rapids.  It  is 
with  this  equipment  that  the  young  amateur  is  achieving 
remarkable  distance  records. 


mitted  to  relax  far  enough  so  that  the 
corners  alternated.  Thus  coils  that 
would  have  been  square,  like  the  box, 
became  circular  with  humps  at  regular 
intervals.  This  caused  the  turns  to 
pass  each  other  at  an  angle  instead  of 


casting  from  north  of  Greenland.  They 
were  so  loud  and  distinct  that  they 
could  be  heard  ten  feet  from  the  phones 
and  all  over  his  radio  room.  As  will 
be  seen  in  the  diagram,  turning  the  dial 
that     controls     regeneration     does     not 


being  parallel,  and  reduced  the  capacity     change  the  wavelength.     The  tuning  is 


between  turns.  Collins  says,  however, 
that  straight-wound  coils  would  serve 
as  well,  that  is,  coils  wound  turn  after 
turn  on  a  cylindrical  form  but  removed 
from  the  form  in  order  to  avoid  the 
effects  its  material   might   produce. 

The  condensers,  he  says,  should  be 
of  the  very  best  material  and  work- 
manship available.  Of  course,  the  capaci- 
ties used  must  be  nicely  adjusted  to  the 
inductances  in  order  to  cover  the  desired 
wavelengths.  The  tuning  condenser 
has  seven  plates. 

The  circuit,  shown  in  figure  1,  is  a 
conventional  one  known  by  various 
names.  The  term  "low  loss,"  originated 
at  the  headquarters  of  the  American 
Radio  Relay  League,  has  been  applied 
to  many  types  of  apparatus  but 
does  not  always  describe  accur- 
ately the  characteristics  of  the 
apparatus  or  the  financial  result 
to  the  purchaser.  The  receiver 
for  very  short  waves,  however, 
must  be  a  low-loss  receiver  to  be 
efficient.  Collins  uses  his  without 
a  ground  connection,  sacrificing 
volume  of  sound  in  the  phones  for 
greater  selectivity.  He  has  elim- 
inated everything  that  can  be  dis- 
pensed with,  in  order  to  get  rid 
of  inductive  and  capacity  effects 
that  are  undesirable.  He  has  no 
vernier  controls,  except  a  rubber 
on  the  end  of  a  lead  pencil  which 
he  uses  at  times  as  a  friction  gear 
in  turning  a  dial.  His  theory  is 
that  if  a  clear  signal,  however 
faint,  can  be  brought  in,  it  can  be 
amplified. 

Using  two  stages  of  audio-fre- 
quency amplification  he  brought 
in  the  voices  of  the  men  on  the 
Bowdoin  when  they  were  broad- 


done  with  one  dial  and  the  only  other 
one  is  that  which  controls  the  regenera- 
tion. The  whole  receiver  is  simplicity 
simplified  and  it  can  be  built  and  oper- 
ated by  anyone  who  can  construct 
and  operate  any  type  of  receiver. 

Has  Two  Transmitters 

/^OLLINS  has  two  transmitters,  one 
^  rated  at  50  watts  and  the  other  at 
1,000  watts.  Even  the  50-watt  outfit 
was  used  successfully  in  working  the 
Bowdoin.  Both  were  designed  for  high 
electrical  efficiency,  convenience  and 
flexibility  of  operation,  as  he  likes  experi- 
mental work. 

It  was  the  day  after  the  tube  for  the 
big   set    was   installed    and    tested    that 


Pal 


Fig.  1.  Wiring  diagram  of  short  wave  receiver  used  by 
Arthur  A.  Collins  for  receiving  messages  and  broad- 
casts from  WNP,  the  Bowdoin  of  the  MacMillan  Arctic 
expedition.  The  two  stage  amplifier  when  used  is 
added  in  the  usual  fashion.  The  circuit  is  the  conven- 
tional regenerative  patterned  after  Armstrong. 


Collins  became  the  only  connecting  link 
between  the  explorers  and  the  folks 
back  home.  For  twenty-two  days  he 
was  the  only  operator  in  communication 
with  the  expedition.  He  worked  from 
8  a.  m.  to  5  p.  m.  daily  and  handled  a 
great  volume  of  traffic,  including  personal 
and  official  messages  and  articles  for  the 
newspapers.  The  National  Geographic 
Society,  which  sponsored  the  expedition, 
sent  and  received  numerous  messages 
through  this  station,  built  and  operated 
by  a  boy,  with  complete  satisfaction. 

The  1KW  tube  uses  4,000  volts  on 
the  plate.  The  only  source  of  supply 
was  the  circuit  which  supplied  light  and 
power  for  the  house.  That  carried  raw 
AC,  which  is  not  ideal.  Pulling  4,000 
volts  from  the  lighting  circuit  every 
time  the  transmitting  key  was  pressed 
stole  most  of  the  juice  from  the  lamps 
around  the  house  and  the  family  led 
a  flickering  existence  until  Arthur  ran 
a  heavy  3-wire  BX  cable  up  from  the 
main  entrance  box  and  thus  put  the 
21-ampere  load  of  the  transmitter  on 
a  separate  circuit. 

The  1KW  transmitter  uses  what  is 
known  as  the  1XAM  circuit.  (Described 
in  QST,  January,  1924.)  When  working 
amateur  stations  in  Australia  and  New 
Zealand,  as  he  frequently  does,  Collins 
tunes  it  to  40  meters.  While  working 
WNP,  MacMillan's  flagship  Bowdoin, 
he  used  wavelengths  of  15,  16  and  21 
meters.  Both  transmitters  look  even 
simpler  than  the  receiver,  as  the  photo- 
graph   shows. 

His  antenna,  during  the  time  he  was 
handling  the  traffic  with  the  Arctic,  was 
a  single  wire  inefficiently  lying  in  a  tree. 
Having  built  a  dream  of  a  house,  on 
Colonial  lines,  his  parents  were  thinking 
more  of  architectural  beauty  than  of 
scientific  achievement,  e-nd  poles  are 
likely  to  be  unsightly.  But  since  Arthur 
established  his  remarkable  record  there 
have  been  erected  on  the  roof  two  thirty- 
foot  masts.  At  the  top  is  a  50-foot 
single- wire  aerial  and  twenty  feet  lowera 
48-foot  counterpoise.  There  is  not  much 
radio  territory  left  for  Arthur  to  reach, 
unless  it  might  be  the  moon  and  Mars, 
but  with  [this  increase  in  the 
efficiency  of  his  station  he  should 
be  able  to  dig  up  a  few  hams  in 
Africa,  Thibet  and  Corea,  if  there 
are  any  there. 

It  is  just  such  experimenters 
as  Arthur  Collins  who  make  the 
amateur  radio  game  one  of  the 
most  interesting  and  beneficial 
hobbies  for  the  rising  generation 
to  ride.  Men  of  mature  years 
could  profiitably  emulate  the 
young  ones,  too,  and  many  of 
them  do. 

With  the  low-priced  and  effici- 
cient  equipment  now  available, 
there  is  certain  to  be  a  big  in- 
crease in  the  number  of  radio 
students,  or  "bugs"  this  winter. 
Anyone  feeling  the  urge  to  g3t 
into  the  game,  but  uncertain  just 
what  are  the  beginners'  first 
steps,  will  do  well  to  confer  with 
the  technical  staff  of  Radio  Age. 
Information  cheerfully  given  upon 
any  phase  of  radio. 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


13 


DIRECTING  THE  NIGHT  AIR  MAIL 


DIRECTING 
mail-carry- 
i  n  g  air- 
planes by  radio, 
flying  between 
New  York  City 
and  Chicago  after 
nightfall,  is  fore- 
shadowed a  s  a 
reality  in  the  light 
of  recent  success- 
ful experiments. 
The  invisible  radio 
waves,  which  seem 
to  be  a  misno- 
mer in  this  in- 
stance, are  to  be 
employed  in  chart- 
ing  the  correct 
course  of  Uncle 
Sam's  "Air  Mail." 

Radio  beacons 
will  supplement 
their  powerful  vis- 
ible  beacons, 
which  project  their 
beams  of  light  for 
miles  along  the 
airway,  as  a  means 
of  insuring  an  un- 
erring course  of 
navigation. 

The  United 
States  Post  Office 
Department,  in 
co-operation  with 
the  Radio  Labora- 
tory of  the  Bureau 
ofStandards, 
recently  conducted 
successful  tests  in 
guiding  aircraft 

between  Maywood  and  Monmouth,  Illi- 
nois, the  latter  point  being  the  location 
of  the  experimental  radio  and  aircraft 
laboratory  of  the  Post  Office  Department. 
These  experiments  were  productive  of 
such  gratifying  results  as  to  warrant  the 
experimental  installation  of  radio  direc- 
tion-finders on  mail-carrying  aircraft 
operating  between  New  York  and 
Chicago.  Then,  airplanes  can  fly  in 
darkness  with  safety  by  means  of  radio 
just  as  now  ships  ply  the  seas  in  foggy 
weather  by  virtue  of  radio  beacons. 

The  use  of  radio  signals  in  guiding 
airplanes  over  distances  of  several  hun- 
dred miles  is  the  result  of  a  refinement 
or  modification  of  a  principle  developed 
by  Francis  W.  Dunmore  of  the  Radio 
Laboratory  of  the  Bureau  of  Standards. 
It  is  described  as  a  directive  type  of 
radio  beacon  and  may  be  applied  in 
guiding  an  airplane,  ship,  or  other 
mobile  unit.  The  sea-going  vessel  or 
airplane  whose  course  is  thus  charted 
is  not  dependent  upon  landmarks  or  the 
magnetic  compass  for  guidance.  Further- 
more, no  elaborate  equipment  is  required 
on  the  mobile  unit,  the  primary  require- 
ment being  a  radio  direction-finder  or 
loop  antenna  and  a  radio  receiving  set, 
of  no  special  design. 

How  It  Is  Done 


BY  RADIO 

Radio  Beacons  Take  the  Place 
of  Searchlights  in  U.  S.  Service 

BY  S.  R.  WINTERS 


Figure  1.      The  photo,  made  by  the  Bureau  of  Standards,  shows  a  double-coil  transmit- 
ting device  used  for  sending  out  radio  signals  whereby  an  airplane  or  ship  may  be  guided 
along  a  straight  course,  thus  taking  the  place  of  less  reliable  methods. 


antennae  on  the  ground,  arranged  at  an 
angle  of  135  degrees  with  respect  to 
each  other.  Signals  from  a  radio  trans- 
mitter— a  quenched  spark  transmitting 
set  being  used  in  the  original  experi- 
ments— are  first  impinged  on  one  coil 
antenna  and  then  the  other,  alternating 
once  every  second.  Radio  waves  are 
thus  intermittently  dispersed  in  a  certain 
direction  from  each  coil,  the  intensity 
of  the  emitted  signal  with  respect  to  the 
plane  of  each  coil  varying  in  accordance 
with  what  the  radio  engineer  terms  the 
figure-of-eight.  A  mail-carrying  air- 
plane, for  instance,  flying  from  Chicago 
to  New  York,  is  assured  that  it  is  navigat- 
ing along  an  appointed  course  if  the 
signals  from  these  two  transmitting  coils 
are  received  with  equal  intensity.  If, 
however,  an  inequality  of  signals  de- 
velops, the  aviator  realizes  that  he  is 
deviating  either  to  the  right  or  left, 
depending  upon  which  arbitrary  signal 
has   lessened   its   intensity. 

The  experimental  type  of  equi-signal 
double-coil  antenna,  illustrated  by  a 
photograph  reproduced  with  this  article, 
was  designed  to  rotate  about  a  telegraph 
pole  as  an  axis.  Each  coil  was  composed 
of  two  turns  of  wire  wound  on  a  frame 
20  feet  square.  While  under  ordinary 
operating  conditions  these  coils  were 
arranged  at  angle  of  135  degrees  with 
T^HE  principle  of  operation  implies  respect  to  each  other,  they  were  sta- 
-*■  the    use    of    two    transmitting    coil     tioned  so  that  their  relative  angles  could 


be  varied.  The 
two  coils  could 
also  be  rotated 
simultaneously 
about  the  tele- 
graph pole  as  an 
axis.  This  arrange- 
ment facilitated 
these  novel  experi- 
ments, as  it  en- 
abled the  receiving 
operator  to  stand 
still  while  the  an- 
gular positions  of 
the  coils  were 
transmitted  to  him 
as  they  were  ro- 
tated. 

A  2- kilowatt 
quenched  spark 
transmitter  was 
employed  with 
these  two  coil  an- 
tenna, a  double- 
pole-double- throw 
switch  being  used 
in  alternating  from 
one  coil  to  the 
other.  As  pre- 
viously stated, 
this  alternation 
occurred  once  each 
second.  The  coils 
were  so  tuned  that 
the  wavelength 
thus  used  Was 
1,000  meters  or 
300  kilocycles,  and 
the  antenna  cur- 
rent in  each  coil 
was  9  amperes. 
Characteristic 
radio-telegraph  signals — in  this  case,  the 
letters  "A"  and  "T" — were  radiated  from 
each  coil  or  loop  antenna.  This  will  be 
the  method  of  procedure  when  the  "Air 
Mail"  is  guided  by  radio  between  Chicago 
and  New  York — that  is,  arbitrary  letters 
from  the  International  Morse  telegraph 
code  will  be  selected  and  alternately 
transmitted  from  a  governed  station. 
Thus  a  sector  or  course  of  travel  is 
established  and  any  deviation  therefrom 
is  indicated  by  an  inequality  of  the  radio 
signals    from    the    two    respective    coils. 

Test  Proves  Successful 

"EXPERIMENTS  initiated  at  the  Bu- 
-*— '  reau  of  Standards  have  been  con- 
tinued by  the  United  States  Air  Service 
at  McCook  Field,  Dayton,  Ohio,  and 
results  have  been  so  satisfactory  that 
recently  an  airplane  was  guided  from 
Dayton  to  Washington,  D.  C,  by  means 
of  a  radio  beacon.  The  crossed-coil 
antenna  used  at  McCook  Field  consisted 
of  two  single-turn  coil  antennae,  50  by 
120  feet  in  dimensions,  and  which  were 
supported  by  three  masts  so  placed  that 
the  angle  between  the  coils  was  135 
degrees.  An  automatic  change-over 
switch  alternately  connected  each  coil 
to  a  5-kilowatt,  500-cycle  quenched 
spark  transmitter.  The  transmitting 
wavelength  was  1,000  meters  and  from  15 
to  18  amperes  of  current  were  used. 
The  radio  receiving  apparatus  used  on 


14  RADIO  AGE  for  November,  1925 

wind   blowing    3% km (2omh.es)  per  hour 


The  Magazine  of  the  Hour 


of     direction-indicating 
use    of    airplane    pilots 


CROSSED   COIL 

ANTENNA     RftDiO 
gERCON 


Fig. 


METHOD  OF  ELIMINATING    EFFECT   OF    \NSW  PRIFT    ON  AN    AIRPLANE 
SHOWING      COURSE     FLOWN     BY     AIRPLANE     AT    Ifcl  KtA  (tOOMlLEs)  PER 
HOUR     IN  ETQUI-SlfcNRL  Z.ONE. 


the  airplane  was  installed  in  the  rear  or 
gunner's  cockpit.  This  consisted  of 
antenna  reel  and  wire,  inductively- 
coupled  tuner,  7-tube  Signal  Corps 
amplifier,  and  batteries.  The  fair  lead 
projected  through  the  flooring  of  the 
cockpit,  thus  permitting  a  wire  to  trail 
on  the  left  side  of  the  fuselage  looking 
forward.  In  addition  to  the  trailing 
wire,  a  coil  of  two  turns  of  insulated  wire 
extending  from  the  trailing  edge  of  the 
upper  wing  and  landing  gear  to  the  rudder 
post  could  be  connected  to  the  radio 
amplifying  unit  and  coupler  by  a  double- 
pole-double-throw  switch. 

"One  of  the  great  advantages  of  this 
system,"  reports  Francis  VV.  Dunmore 
of  the  Radio  Laboratory  of  the  Bureau 
of  Standards,  "over  the  method  of  em- 
ploying a  radio  direction  finder  on  the 
airplane  or  on  shipboard  is  that  the  effect 
of  side  drift  may  be  immediately  noticed 
and  corrected  by  heading  the  airplane 
at  the  correct  angle  in  to  the  wind,  thus 
enabling  a  pilot  to  maintain  a  straight 
course  along  the  line  of  direction  to  the 
transmitting-coil  beacons. 

"In  aerial  navigation  this  is  much 
more  important  than  in  marine  naviga- 
tion, as  the  effect  of  side  drift  due  to 
crosswinds  is  often  very  marked.  The 
effect  of  cross  winds  on  an  airplane 
navigating  by  means  of  magnetic  or 
ordinary  radio  direction  finder  bearings 
is  illustrated  in  one  of  the  diagrams  repro- 
duced with  this  article.  It  will  be  seen 
that  under  these  conditions  the  airplane 
may  deviate  considerably  from  its  true 
course.      By    means    of    an    equi-signal 


crossed-coil  radio  beacon,  an  airplane 
may  maintain  a  straight  course  regard- 
less of  cross  winds  and  visibility  condi- 
tions." 


'T'HE     value 
-*-  beacons    for 

cannot  be  over-estimated.  The  in- 
creasing air  travel,  together  with  the 
frequent  low  visibility  during  storms 
or  other  atmospheric  disturbances,  makes 
it  almost  imperative  that  some  definite, 
safe  and  constant  means  be  adopted  to 
guide  the  air  traveler  on  his  way. 

The  navigators  of  old  Were  practically 
helpless  without  beacons,  although  the 
radio  compass  has  now  practically  made 
navigation  error-proof.  The  adaptation 
of  the  radio  compass  to  air  work,  with 
particular  emphasis  laid  on  the  beacon 
scheme,  should  do  a  great  deal  to  iron 
out  difficulties  which  aviators  have 
had  to  encounter  in  their  flights. 

Naturally,  the  radio  compass  aboard 
an  air  machine  is  too  bulky  a  proposi- 
tion to  be  considered,  so  the  beacon 
after  all  seems  to  be  the  most  feasible 
project  yet  developed. 

Guiding  Steamships 

Old  timers  will  probably  compare  the 
aerial  method  of  holding  to  a  course  to 
the  buried  cable  in  New  York  Harbor 
some  years  ago  when  underwater  oscil- 
lators, one  located  on  the  port  and  the 
other  on  the  starboard,  were  used  to 
keep  track  of  a  signal  being  emitted  by 
the  cable  laying  on  the  floor  of  the  harbor. 
By  noting  the  intensity  of  the  signal 
received  in  the  port  and  starboard  re- 
ceivers the  pilot  (the  skipper)  was  en- 
abled to  hold  the  vessel  to  a  true  course. 
This  was  exceptionally  valuable  in  foggy 
or  heavy  weather  when  there  was  a 
possibility  of  a  collision  if  the  vessel 
strayed  far  from  her  beaten  path. 


WIND     SLOWING      32KM(20MILES)   PER   HOUR 


Fig.  3 


EFFECT    OF  wTnD    drift   ON   A IR  PLANE,  SHOWING     COURSE.    TAKEN 
BY   AIRPLANE   WHEN    FLYING    AT    \U  KM  (loo  MILES)  PER  HOUR 
AND   NAVIGATING    BX  MEANS    OF     DIRECTION    FINDER   BEARING-S 
9NLY. 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


15 


A  New  Use  for  3-Element  Tubes 

A  WINDLESS,  PIPELESS, 
PIPE  ORGAN 


IN  THE  twenty  years  since  the  inven- 
tion of  the  audion  by  DeForest, 
the  three-element  vacuum  tube  has 
been  put  to  a  large  variety  of  uses  and 
new  applications  are  constantly  being 
made.  Besides  its  well-known  functions 
as  a  detector  and  amplifier,  it  is  used  to 
drive  oscillators  of  every  description  from 
the  small  experimental  units  of  the  radio 
laboratory  to  the  large  powerful  types 
which  furnish  the  carrier-wave  for  broad- 
casting purposes. 

The  pitch  of  a  musical  instrument 
depends  on  certain  properties  of  the 
substances  whose  vibrations  produce  the 
various  notes.  In  the  piano  it  varies 
with  the  length,  tension  and  weight  of  the 
string.  In  the  pipe-organ  it  depends 
chiefly  on  the  length  of  the  pipe  and  on 
whether  one  end  is  open  or  closed.  In 
the  case  of  an  oscillating  electrical  circuit 
the  controlling  factors  are  the  capacity 
and  inductance  as  given  by  the  equation, 

1 


By  ].  C.  JENSEN 


Dept.  of  Physics.  Nebraska  Wesle: 


core  transformer,  T.  The  core  is  built 
up  of  laminated  steel  with  outside  dimen- 
sions 4x5  inches  and  1  inch  deep.  The 
width  of  each  piece  of  steel  is  1  inch, 
which  leaves  a  rectangular  hole,  2x3 
inches  in  the  center.  To  facilitate  wind- 
ing, the  steel  plates,  taken  from  a  burnt- 
out  power  transformer,  were  cut  into  the 
shape  of  an  L,  5x3x1  inches,  and  piled 
for  each  half  so  that  alternate  layers 
extend  in  the  directions  a  and  b  as  shown 
in  the  drawing. 

After  the  coils  have  been  wound  on  the 
resulting  U  shaped  forms,  the  laminations 
at  the  ends  are  slipped  over  each  other 
so  as  to  form  a  solid  mass  of  steel,  and 
pushed  into  place  by  the  use  of  a  bench 
vise.  Holes  were  then  drilled  in  each 
end  of  the  core  and  bolts  through  these 
holes  held  the  entire  structure  together. 


2*VLC 
■where  n  is  the 
number  of  oscilla- 
tions per  second, 
L  the  inductance 
of  the  circuit  in 
henries  and  C  its 
capacity  in  farads. 
Since  this  equa- 
tion holds  for  all 
values  of  L  and  C, 
it  follows  that  if 
their  values  are 
properly  chosen  a 
vacuum-tube  cir- 
may  be  made  to 
oscillate  with  fre- 
quences within 
the  range  of  the 
human  ear. 

A  Vacuum  Tube 
Oscillator 

TH  E  vacuum 
tube  oscillator 
described  herein  is 
the  outgrowth  of 
considerable  labo- 
ratory experimen- 
tation on  low- 
frequency  circuits. 
As  will  be  noted 
from  Fig.  1,  the 
Hartley  circuit  is 
used,  although 
some  of  the  others 
could  also  be  made 
to  serve  the  pur- 
pose. The  most 
difficult  part  of  the 
apparatus  to  con- 
struct is  the  iron- 


Fig.  1 

The  wiring  diagram  for  the  pipeless  pipe 
organ,  an  outgrowth  of  much  experiment 
by  Prof.  Jensen.  Although  other  circuits 
could  be  used  to  advantage,  Hartley's  was 
used  as  being  best  suited. 


<#  llixiiii 


c.  cxc>c*cs  ccSS 


To  A  m  p  1  i  j  i  e.  r 


The  primary  coil  consists  of  3000  turns 
of  No.  26  enameled  wire  insulated  from 
the  core  and  between  layers  with  empire 
cloth. 

A  tap  is  taken  out  at  the  1800th  turn 
for  the  filament  connection  and  if  the 
transformer  is  intended  for  general 
experimental  purposes,  it  is  a  good  plan 
to  take  out  a  tap  for  each  300  turns, 
beginning  with  the  1200th.  The  secon- 
dary is  wound  in  a  similar  way  with  300 
turns  of  wire.  Any  hard  amplifier  tube 
will  serve  in  that  position.  The  UV201A 
gives  very  good  results,  while  for  maxi- 
mum volume  the   UV202  may  be  used. 

Only  One  Octave 

TN  THE  experimental  outfit  here 
-*■  described,  one  octave  only  was  pro- 
vided for.  The  condenser,  C,  is  a  43- 
plate  variable  in  a  metal  case,  the  latter 
being  filled  with  transformer  oil  so  as  to 
increase  the  maximum  capacity  to  about 
.003  Mfds.  The  fixed  condensers  Q, 
C2,  C3,  etc.  were 
made  out  of  an  old 
high-voltage  paper 
condenser.  Trials 
with  small  labora- 
tory units  showed 
that  the  value  of 
Ci  should  be  about 
.01  Mfd.  to  give  a 
pitch  of  C  —  256 
vibrations  per  sec- 
ond. A  paper 
condenser  of  that 
magnitude  was 
connected  in  and 
the  pitch  tested 
against  a  tuning 
fork.  Approximate 
adjustment  was 
made  by  trimming 
the  tinfoil  between 
layers  of  paper, 
and  final  tuning  to 
the  exact  note  was 
obtained  by  the 
use  of  the  variable 
condenser. 

To  keep  Ci  con- 
stant, the  paper 
and  tinfoil  parts 
were  tightly 
clamped  between 
two  pieces  of  bake- 
lite.  C2,  C3,  etc., 
were  constructed 
in  a  similar  man- 
ner. With  all  the 
key-switches  open, 
the  apparatus 
would  still  give  out 
a  high-  pitched 
note  due  to  the 
variable     conden- 


16 


RADIO  AGE  for  November,  1925 


in 

Fig.  2.    A  close-up  of  the  remarkable  key-board  for  the  organ  devised  by  Prof.  Jensen. 
The  transformer  and  oscillator  tube  are  also  shown  in  this  photo. 


ser.  This  can  be  obviated  in  either  of 
two  ways.  Instead  of  the  permanent 
connection  from  C  to  the  condenser- 
transformer  leads,  a  separate  wire  can 
be  run  from  its  upper  side  to  the  contact 
points  of  the  switches  Ci,  C2,  C3,  so  that 
the  variable  condenser  is  in  circuit  only 
when  a  key  is  struck. 

Another  plan  is  to  connect  a  1  Mfd. 
condenser  to  the  upper  side  of  a  bar, 
joining  all  the  keys  in  such  a  way  that 
this  large  condenser  is  in  circuit  only 
when  all  keys  are  up,  its  capacity  being 
sufficient  to  make  the  note  of  the  oscil- 
lator too  low  to  be  audible. 

The  output  of  the  transformer  is  put 
into  an  amplifier  of  two  or  three  stages. 
Fig.  2  shows  a  close-up  view  of  the  key- 
board, transformer  and  oscillator  tube, 
while  Fig.  3  illustrates  the  entire  appar- 
atus including  a  two-stage  power  am- 
plifier. With  a  little  care  in  adjusting, 
the  notes  produced  may  be  made  true 
to  pitch  and  of  good  quality.  The  volume 
of  sound  depends  wholly  on  the  amount 
of  amplification  applied,  and  it  is  obvious 
that  greater  ranges  in  pitch  can  be  added 
at  will. 

Similar  to  Pipe  Organ 

HPHE  action  of  the  keys  in  this  device 
-*-  is  the  same  as  that  of  any  electrically 
controlled  pipe  organ,  except  that  each 
key  has  a  set  of  contacts  which  opens  and 
closes  its  respective  condenser  circuits, 
instead  of  a  relay  circuit,  as  is  the  case 
with  the  usual  electrically  controlled 
pipe  organ. 

The  keyboard  of  this  radio  organ  is 
nothing  more  than  a  number  of  hinged 
pieces  of  wood,  each  having  a  set  of  con- 
tacts and  a  spring  to  hold  the  key 
switch  open. 

In  the  event  that  the  experimenter 
desires  to  work  with  the  lower  notes  of 
the  piano  or  organ  scale,  it  may  be 
necessary  to  use  one  of  the  newly  develop- 
ed cone  type  loud  speakers  in  the  output 
switch,  as  it  is  often  the  case  that  the 
usual  type  of  horn  speaker  will  not 
respond  to  the  lower  notes  of  the  scale. 


The  cone  type  of  speaker  will  also  give 
better  satisfaction  if  a  wide  range  of 
frequencies  is  to  be  made  use  of.  There  is 
practically  no  limit  as  to  the  quality  of  the 
tones  which  a  device  of  this  kind  can  be 
called  upon  to  produce,  since  a  resis- 
tance or  impedance  coupled  amplifier 
and  cone  type  speaker  can  be  connected 
to  the  output  circuit  of  the  oscillator 
tube.  This  form  of  amplifier  and  speaker 
will  faithfully  reproduce  all  the  tones 
generated  without  the  slightest  distor- 
tion. 

It  may  be  found  that  while  operating 
this  tube  organ  that  a  slight  disturbance 
occurs  in  the  radio  receiving  set  when 
both  are  operated  at  the  same  time.  If 
this  interference  of  disturbance  is  trouble- 
some, it  can  be  eliminated  by  completely 
shielding  the  oscillator-circuit,  (Fig.  1) 
with  a  copper  or  tin  foil  cover  box. 


The  Magazine  of  the  Hour 

Establishing    Octaves 

pONDENSER  CI,  of  approximately 
^-^  .01  mfd.  capacity  gave  a  pitch  of 
C,  or  -256  vibrations  per  second,  the 
lowest  note  of  the  particular  octave  for 
which  this  device  was  made.  The  re- 
maining condensers,  C2,  C3,  etc.,  will 
naturally  have  to  be  of  a  smaller  capacity 
than  .01  mfd.  The  capacities  of  these 
condensers  can  be  altered  until  the  result- 
ant pitch  is  obtained.  This  can  be  accom- 
plished by  altering  the  capacity  of  each 
of  the  condensers,  C2  and  C3  until  the 
note  produced  is  similar  to  that  given 
when  the  corresponding  keys  of  thej 
piano  are  sounded. 

By  employing  the  method  of  establish- 
ing the  octave,  described  above,  several 
other  octaves  can  be  included  by  provid- 
ing additional  keys  and  corresponding 
condensers  and  adjusting  them  by  com- 
parison with  the  piano  or  by  ear  until 
the  desired  notes  are  produced. 

There  has  been  quite  an  insistent 
demand  on  the  part  of  a  certain  type  of 
radio  experimenters  for  an  article  on  an 
audio  oscillator.  The  scheme  outlined  by 
Prof.  Jensen  seems  to  cover  the  subject 
quite  well  and  we  believe  his  article  will 
enable  many  of  our  readers  so  inclined 
to  go  ahead  with  their  own  work  on  an 
audio  oscillator.  The  range  of  frequencies 
can  of  course  be  determined  at  will  by 
the  selection  of  different  sized  condensers 
as  outlined  by  Prof.  Jensen  and  with  the 
trimming  process  employed  one  may  get 
the  various  capacities  down  to  a  nicety. 


Don't  miss  the  December  num- 
ber of  RADIO  AGE.  Chock 
full  of  inspiration  and  topped 
off  with  the  "Radio  Age 
Model  Receiver."  On  the 
stands  November  15. 


Fig.  3.    The  entire  apparatus,  including  the  two  stage  power  amplifier.     Fans  who  build 
this  novel  organ  are  asked  to  write  in  concerning  the  results  obtained. 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


17 


f/GURF  1 


©       0 


VRF 


•SHIELD 


WWW»- 


<wwv\ 


SCHEMATIC  ClfiCUfT  D/Mf/fM  OF  THE 
"SPEC //> 'I    FOUR* ' /PECE/l/Etf 


R--1 


A  New  LOW  LOSS  "Special  Four 


)) 


An  Efficient  Long-Distance  Set 

Combining  Regeneration  and  a 

Stage  of  Adjustable  Tuned  RF 

By  H.  FRANK  HOPKINS 


AS  THE  cold  weather 
approaches,  all  of 
the  DX  hounds  start 
polishing  up  the  old  solder- 
ing iron  and  looking  for  new 
ideas  in  receiving  circuits, 
and  here  is  one  right  off  the 
fire.  A  combination  of  the 
old  reliable  DX  regenera- 
tive set,  less  the  trouble- 
some howls  and  squeals,  with  a  stage  let  us  analyze  the  circuit.  We  will  start 
of  "adjustable"  tuned  radio  frequency  at  the  incoming  or  radio  frequency  end 
amplification    that    will    reach    out    and     and    see    what    takes    place.      By    radio 


bring  home  the  distant  stations  to  your 
heart's  content,  and  two  stages  of  audio 
frequency  amplification  to  rattle  the 
window  panes. 

This     circuit     has     shown     surprising 
selectivity    while    being    worked    within 


the    variable    condenser    as 
RC. 

The  Two-Circuit  Coil 

BY  AN  adjustable  stage 
of  tuned  radio  fre- 
quency, we  mean  a  two 
circuit  coil  with  the  variable 
condenser  as  described 
above,  with  the  windings 
mounted  so  that  they  can  be  moved  to 
various  distances  from  one  another,  as 
shown  in  Figure  2.  This  feature  enables 
one  to  increase  or  decrease  the  antenna 
coupling  as  desired.  When  this  is  once 
set,  it  need  not  be  changed,  unless  the 
operator  desires  to  sharpen  the  tuning 
so  as  to  cut  out  some  nearby  station. 
This    is    accomplished    by    reducing   the 


frequency  amplification,  the  incoming 
signal  is  amplified  at  radio  frequency, 
or  at  a  frequency  above  audibility, 
depending  on  the  wavelength  of  the 
incoming  signal.  By  tuned  radio  fre- 
quency, we  mean  that  the  radio  frequency 
a  mile  and  a  half  of  two  1500- watt  broad-  transformer  is  capable  of  being  tuned  to  coupling  or  moving  the  coils  farther 
casting  stations  and  one-half  of  a  city  filter  signals  of  various  frequencies  and  apart,  or  he  may  increase  volume  and 
block  from  station  WIBO,  which  is  block  all  other  signals  of  different  fre-  distance  by  closer  coupling,  which  is 
sending    out    1000    watts.       During    the     quencies.       The     most     common     tuned     obtained    by     moving    the    coils    closer 

radio  frequency  circuits  have  a  two-  together.  This,  however,  reduces  the 
circuit,  air  core  transformer,  one  winding  selectivity  of  the  set  and  it  is  suggested 
acting  as  an  aperiodic  primary.  This  that  when  once  a  good  setting  has  been 
winding  usually  has  from  eight  to  fifteen 
turns  of  insulated  copper  magnet  wire, 
about  No.  22  gauge,  and  the  other  wind- 
ing as  a  tuned  secondary  usually  con- 
sisting of  from  forty-five  to  sixty  turns 
of  the  same  size  wire,  when  a  .00035 
Mf.  variable  condenser  is  shunted  across 
'T'HE  cost  of  building  this  set  is  com-  its  winding.  By  changing  the  capacity 
*-  nnrativelv  small   when  nnp  rnnsidpr«     of  this   condenser,   the   circuit   is   tuned 

to  filter  various  frequencies  or  to  pass 
signals  of  a  given  wavelength  to  the 
grid  of  the  radio  frequency  tube,  where 
they  are  amplified,  or  strengthened. 
This  coil  is  shown  in  the  schematic 
circuit  diagram,  Figure  1,  as  VRF.  and 


first  part  of  September,  it  reached  out 
almost  two  thousand  miles  and  brought 
in  signals  on  the  loud  speaker- — and 
that  is  going  some  for  that  time  of  the 
year.  In  fact,  for  distance  on  a  seventy 
foot  antenna,  it  beat  an  eight  tube 
super-heterodyne  using  a  loop  and  being 
operated  at  the  same  time. 

Cost  Is  Not  Great 

,HE  cost  of  building  this  set  is  com- 
paratively small  when  one  considers 
that  the  popular  trend  is  for  five,  six 
and  even  eight  tube  sets,  and  it  will 
stand  up  and  bring  them  in  alongside 
of  the  best  of  them. 

In  selecting  a  receiver,  it  is  always  a 
good  plan  to  find  out  how  it  works,  so 


obtained,  the  coils  be  locked  in  that 
position,  or  that  position  marked  so  as 
to  be  able  to  go  back  to  it  as  desired. 

In  this  circuit,  we  have  all  of  the  above 
features,  with  the  addition  of  a  brass 
shield  between  the  primary  and  secon- 
dary coils  of  the  transformer  VRF. 
This  shield  was  found  to  reduce  most  of 
the  strong  induced  currents  that  were 
responsible  for  considerable  foreign  noises 
in  the  receiver.  This  shield  is  grounded 
to  the  negative  side  of  the  filament,  or 
"A"  battery,  and  is  kept  in  about  the 
center  of  the  air  gap  between  the  two 
coils.  (Turn  the  page) 


18 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


The  plate  element  or  output  terminal 
of  the  radio  frequency  tube  RF  in  this 
circuit  is  then  connected  to  the  primary 
side  of  a  three  circuit  tuner,  designated 
3CT  in  Figure  1.  A  three-circuit  tuner 
is  a  set  of  three  coils,  two  stationary 
and  one  movable.  The  first  coil  is  known 
as  the  primary  and  has  about  twelve 
turns  of  No.  22  insulated  copper  magnet 
wire;  the  second  coil  is  known  as  the 
secondary  and  has  about  fifty-five  turns 
of  the  same  size  wire.  A  variable  con- 
denser is  shunted  across  this  secondary 
coil  and  the  combination  works  the 
same  as  the  radio  frequency  unit  just 
described.  The  third  coil  is  movable 
and  is  located  inside  of  the  other  wind- 
ings. It  is  known  as  a  tickler  coil  and  has 
about  twenty-five  turns  of  the  same 
size  wire;  this  coil  is  what  produces 
regeneration    and   is   a    volume   control. 

The  Secondary  Connection 

'  |  VHE  secondary  side  of  this  three 
*■  circuit  tuner  is  connected  to  the  grid 
of  the  detector  tube  D,  through  a  grid 
leak  resistance  and  small  fixed  condenser 
GL.  This  grid  leak  and  condenser  is 
used  to  insure  an  even  grid  bias  potential 
or  grid  voltage.  The  plate  of  the  de- 
tector tube  is  connected  to  one  side  of 
the  tickler  coil;  the  other  side  of  the 
tickler  coil  is  connected  to  the  positive 
side  of  a  forty-five  volt  plate  or  B  battery 
through  a  set  of  head  phones  or  the 
primary  coil  of  an  audio  frequency 
transformer,  thus  producing  regenera- 
tion, or  strengthening  the  output  of  the 
detector  tube,  which  has  rectified  the 
incoming  signal  from  the  inaudible 
radio  frequency  to  an  audible  frequency, 
or  a  frequency  that  will  produce  sound 
in  the  head  phones  or  loud  speaker. 

This  output  is  usually  connected  to 
the  primary  winding  of  an  audio  fre- 
quency transformer.  By  audio  fre- 
quency amplification,  we  mean  amplifica- 
tion of  the  signal  which  has  been  rectified, 
or  changed  to   a  frequency   low  enough 


to  produce  an  audible  vibration  of  the 
diaphragm  in  the  receivers  of  the  loud 
speaker.  By  adding  stages  of  audio 
frequency  amplification,  we  increase  the 
output  strength  of  the  set  and  conse- 
quently get  more  volume. 

Two  such  stages  of  audio  frequency 
amplification  are  usually  employed,  and 
sometimes  three,  but  more  than  three 
stages  tend  to  distort  the  signal  and 
are  therefore  not  desirable. 

All  that  remains  to  be  described  are 
the  batteries  and  the  ground  and  an- 
tenna connections.  The  filament  or 
"A"  battery,  as  we  all  know,  is  used 
to  heat  the  filament  of  the  tubes,  causing 
an  emission  of  electrons  to  take  place 
within  the  tube,  the  flow  of  which  is 
regulated  by  the  grid  element  of  the 
tube.  The  plate  or  B  battery  is  con- 
nected to  the  plate  element  of  the  tube 
through  the  receivers  or  the  secondary 
of  a  transformer.  The  battery  furnishes 
the  high  voltage  necessary  to  pass  a 
current  from  the  filament  to  the  plate 
element  of  the  tube,  making  a  completed 
circuit  through  the  phones  or  loud 
speaker  so  that  the  current  will  flow  and 
the  variations  will  be  reproduced  by 
sound. 

The  Materials 

NOW  that  we  have  analyzed  the  cir- 
cuit, let  us  go  about  getting  the 
materials  ready  to  build  the  set.  Every- 
thing that  will  be  required  is  listed 
below.  Each  part  bears  a  designation. 
The  same  designation  is  shown  on  the 
circuit  diagram  and  is  used  throughout 
the  article  so  as  to  enable  the  reader  to 
more  easily  distinguish  each  part  and 
to  properly  place  it  in  the  circuit.  The 
parts  are  as  follows: 

One — Adjustable  radio  frequency 
transformer  (VRF).  Described  later 
in  this  article. 

One — Three  circuit  tuner  (3CT). 

Two — .00035  Mfd.  variable,  straight 
line-wavelength  condensers  (RC  and 
DCl. 


Three — 1"    composition    dials    (for 
3GT,  RC  and  DC). 

Two — 3  to  1  audio  frequency  trans- 
formers (Tl  and  T2). 

One— .00025    Mfd.    grid    leak    con- 
denser (GL). 

One — 2  megohm,  tubular  grid  leak 
resistance  (GL). 

Four — UV    tube    sockets    (RF,     D, 
AF1  and  AF2). 

One — 6  1-2  ohm  rheostat  (R). 

One — 25   ohm   rheostat    (D). 

One — Two  circuit  phone  jack, with 
filament  cut  off   (HP). 

One — Single     circuit     phone     jack 
(LS). 

Seven — Binding  posts  (A,  G,  B  amp 
B  det,  BR,  F+,  and  F-). 

One — A  battery  switch   (SW). 

One — Composition    panel,    7"x2"x 
3-16". 

One — Base    board,    7"x23"x1/z"- 

XXX — Miscellaneous     mounting 
screws,  wire,  solder,  etc. 


The  first  step  in  the  assembly  of  the 
set  will  be  to  lay  out  and  drill  the  panel 
and  shelf.  This  is  usually  done  by  placing 
the  parts  around  until  a  satisfactory 
arrangement  has  been  found.  Starting 
with  the  shelf,  the  holes  for  mounting 
each  piece  are  then  marked  with  a  sharp 
instrument,  the  parts  removed  and  the 
holes  drilled.  It  would  be  well  to  drill 
the  holes  that  pass  the  movable  shafts 
through  the  panel  at  least  one-half  of 
an  inch  in  diameter,  to  prevent  them 
from  binding  against  the  panel  and 
turning  hard.  Oftentimes  it  saves  a 
great  deal  of  time  in  fitting. 

When  the  holes  for  mounting  the 
parts  have  all  been  located  and  drilled, 
it  would  be  well  to  give  the  panel  a  velvet 
finish,  by  rubbing  it  lengthwise  with  a 
piece  of  fine  sand  paper  that  has  been 
dipped  in  oil.  All  of  the  marks  and 
scratches  will  disappear  and  the  panel 
will  have  a  soft,  dull  finish  that  will  not 


5     ,*    *S    *i 

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RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


19 


mark  up  as  easily  as  the  highly  polished 
surface. 

A  great  deal  could  be  written  about 
the  placing  of  the  parts  in  relation  to 
each  other,  but  there  are  only  a  few 
pointers  necessary,  and  they  are:  Keep 
the  radio  frequency  transformer  as  far 
away  from  the  three  circuit  tuner  as  is 
convenient.  In  no  case  let  it  come  within 
five  inches  of  the  tuner;  also,  keep  the 
three  circuit  tuner  as  far  away  from  any- 
unshielded  audio  frequency  transformer 
as  possible,  and  at  least  five  inches. 
If  the  audio  frequency  transformers  are 
not  shielded,  that  is,  if- they  are  not 
encased  in  a  metal  shell,  they  will  have 
to  be  separated  and  mounted  at  right 
angles  to  one  an- 
other. All  of  the 
above  points 
should  be  followed 
out,  as  if  these 
parts  fall  within 
the  inductive  or 
magnetic  fields  of 
one  another,  howls 
and  squeals  will 
result  and  the  set 
will  be  practically 
worthless. 


and  antenna  leads.  All  other  connections 
are  considered  power  or  low  frequency1 
leads  and  are  not  as  liable  to  interference 
as  are  the  others.  Solder  all  connections 
and  see  that  the  terminal  nuts  are  turned 
down  as  tight  as  possible.  A  loose  con- 
nection is  often  a  hard  thing  to  find  and 
is  the  cause  of  much  noise  in  the  receiver. 

For  those  who  like  to  wind  their  own 
coils,  the  construction  of  the  adjustable 
radio  frequency  transformer  is  explained. 
The  construction  of  a  good  three  circuit 
tuner  has  been  described  often  and  by 
referring  to  a  back  number  of  RADIO 
AGE,  or  to  the  RADIO  AGE  ANNUAL, 
a  suitable  unit  can  be  found  very  easily. 

The  material  required  for  making  this 


Wiring    the    Set 

WHEN  all  of 
the  parts  have 
been  mounted  and 
the  shelf  fastened 
to  the  panel,  the 
set  will  be  ready 
to  be  wired,  but 
before  we  start  to 
wire  the  set,  it 
may  be  well  to 
consider  just  what 
the  wiring  accom- 
plishes or  is  meant 
to  accomplish  in  a 
receiver.  Many 
radio   fans    who 

make  their  own  receivers,  have  a  great 
feeling  of  relief  when  the  panel  has 
been  drilled  and  the  instruments  all 
mounted.  They  say,  "Now  all  I  have 
to  do  is  wire  it  up,"  and  that  is  about 
all  they  do;  just  wire  it  up  in  a  slipshod 
manner   and    with   the   nice   square   bus 


CUT  FROM  '/ti'F/BI?F 


22  COPPER 

MAGNET  WIRE- 


■/usior 


HOLES    TO 
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TENSION  CLIPS^ 

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radio  frequency  transformer  (VRF)  is 
shown  in  figures  2  and  3,  together  with 
the  assembly  of  the  completed  unit. 

In   winding  the  coils,   care  should   be 

taken    to    see    that    the    primary    and 

secondary    units    have    the    windings    in 

the    same    direction;    that    is,    the    wire 

bar  wiring,  with  long  runs  and  nice  square     should  be   wound   upon   the   forms   in   a 

corners,  a  nice-looking  job,   but  a  very     clockwise     direction.       This     is     accom- 


to  the  negative  filament  lead  of  the  set 
at  the  binding  post  F — . 

The  tuning  of  this  set  is  comparatively 
simple.  The  condensers  RC  and  DC 
control  the  wavelength  and  the  tickler 
coil  of  the  three  circuit  tuner  (3CT) 
control  the  volume.  The  filament  cur- 
rent for  the  detector  tube  is  controlled  by 
the  rheostat  D  and  the  rheostat  R  con- 
trols the  filaments  of  the  radio  frequency 
and  audio  frequency  tubes  (RF,  AF1  and 
AF2). 

If  the  set  does  not  tune  sharply  enough 
at  the  start,  move  the  coils  of  the  trans- 
former (VRF)  farther  apart,  until  the 
desired  selectivity  is  obtained.  When 
the  distance  results  do  not  seem  to  be  all 
that  should  be  ex- 
pected, move  the 
coils  of  this  same 
transformer  closer 
together,  until 
maximum  coup- 
ling is  obtained. 
This  will  make  the 
set  tune  more 
broadly,  but  will 
bringin  the  distant 
signals  loud  and 
clear. 

The  set  may  be 
logged,  if  the  coils 
of  the  radio  fre- 
quency transform- 
er are  set;  that  is, 
if  a  good  average 
setting  is  obtained, 
and  the  coils  locked 
in  this  position. 
By  moving  these 
coils,  the  setting 
of  the  condenser 
RC  is  changed,  and 
would  fall  a  little 
off  from  that  which 
was  obtained  at 
another  setting. 
The  writer 
would  be  very  interested  in  hearing  of 
the  results  obtained  with  this  set  in 
various  parts  of  the  country  and  under 
various  conditions  and  would  appreciate- 
hearing  from  those  who  build  it. 


£ 


seu>r/p  to smi f to 


inefficient  piece  of  work,  as  this  type  of 
wiring  usually  has  enough  length  in 
the  leads  to  wire  up  two  sets. 

Many  sets  wired  up  in  this  manner 
work  poorly,  because  the  wiring  does 
not  accomplish  what  it  is  supposed  to. 
The  wiring  of  a  set  is  supposed  to  con- 
nect the  instruments  into  the  circuit  so 
that  they  will  all  work  together  with  as 
little  resistance  or  interference  as  possible. 
From  this  it  is  found  that  the  shorter 
the  leads  the  less  the  resistance  and 
internal  capacity  of  the  set,  so  let  us 
go  about  wiring  the  set  with  rubber 
covered,  stranded  copper  wire,  or  cotton 
covered  will  do,  making  the  runs  as 
short  as  possible. 

All  leads  carrying  high  frequency 
currents  should  be  run  separately  and 
away  from  one  another.  Never  run  a 
lead  carrying  high  frequency  current 
parallel  to  another  lead.  By  high  fre- 
quency leads,   we  mean  the  grid,   plate 


plished  by  holding  the  form  in  a  vertical 
position,  at  right  angles  to  the  body  and 
winding  the  wire  over  the  top,  away 
from  the  body  and  back  on  the  under 
side  toward  the  body.  Twelve  turns  of 
No.  22  Double  silk  or  cotton  covered, 
copper  magnet  wire  will  be  wound  on 
the  primary  form  and  fifty  turns  of  No. 
22  double  silk  or  cotton  covered,  copper 
magnet  wire  will  be  wound  on  the 
secondary  coil.  This  wire  should  be 
wound  as  tight  as  possible  without  affect- 
ing the  shape  of  the  form.  Each  end  of 
the  coils  should  be  securely  fastened  to 
the  form  by  passing  the  wire  through 
two  small  holes  made  for  this  purpose 
This  will  keep  the  wire  from  coining 
loose  when  the  coils  are  moved  around 
on  the  spindle. 

The  brass  shield  shown  in  Figure  3 
is  cut  from  20  gauge  stock  and  is  four 
inches  in  diameter.  A  flexible  lead  is 
soldered    to    this    shield    and    connected 


yHE  technical  staff  of  RADIO 
-*  AGE,  together  with  the  engineers 
of  several  leading  radio  manu- 
facturers, have  devised  another  effi- 
cient receiver  for  RADIO  AGE 
readers  to  experiment  with.  Like 
the  receiver  described  in  the  fore- 
going article,  it  will  reach  out  for 
great  distance  at  all  times  of  the 
year,  besides  being  about  as  selective 
as  it  is  possible  to  make  a  receiver. 
This  receiver,  of  the  tuned  radio 
frequency  type,  has  just  been  per- 
fected after  several  months  of  experi- 
menting, and  will  be  presented  to 
our  readers  with  full  size  RADIO 
AGE  BLUEPRINTS,  in  the 
December  issue.  Watch  for  this 
gala  number,  and  if  you  are  not  a 
subscriber,  order  from  your  news 
dealer  NOW! 


20  RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


to 


? 


Coming  in  Our  December 

Issue— "The  Radio  Age 

Model  Receiver" 


READERS    who    make    their    own    sets    will 
welcome   this   most   complete   how-to-make 
article   this   magazine   has   ever  published. 

The  receiver  will  be  a  five-tube  tuned  radio 
frequency  outfit.  Every  part  will  be  listed  under 
the  name  of  the  manufacturer  or  the  trade  name 
so  that  you  will  not  have  to  ask  a  question  as  to 
what  apparatus  to  select. 

The  article  will  be  illustrated  with  line  drawings, 
a  wiring  diagram  and  several  full  page  size  blue- 
prints. 

Even  the  accessories,  such  as  loud  speaker,  bat- 
teries,  etc.,  will  be  suggested. 

If  you  are  planning  to  build  another  set  this 
Winter  you  will  make  no  mistake  in  investing 
your  time  and  money  in  this  "Radio  Age  Model 
Receiver." 

The  complete  working  model  of  this  beautiful 
set  will  be  on  exhibition  in  the  Radio  Age  booth 
at  the  Fourth  Annual  Chicago  Radio  Show, 
Coliseum  Building,  whch  opens  on  Nov.  23. 
See  it  there!  This  de  luxe  set  will  be  given  away 
to  one  of  the  lucky  fans  who    visit    our    booth. 


'TMIIS  superior  how-to-make  feature  will  not 
■*■  only  have  the  imprint  of  the  skill  of  our  own 
technical  staff — one  of  the  very  best  in  the  radio 
field — but  the  editor  of  Radio  Age  has  enlisted 
manufacturers  of  quality  apparatus  to  assist 
us  in  making  this  receiver  what  its  name  implies 
— a   model  outfit. 

John  B.  Rathbun,  whose  blueprints  and  arti- 
cles in  each  issue  of  RADIO  AGE  are  followed 
by  fans  all  over  the  world,  will  write  the  descrip- 
tion of  this  model  receiver  and  he  will  cover  the 
story  down  to  the  very  last  detail. 

Frank  D.  Pearne,  technical  editor  of  Radio 
Age  and  chief  instructor  in  electricity  at  Lane 
Technical  High  School,  Chicago,  will  assist  in 
the  tests  that  will  be  made  before  any  part  or 
accessory  is  included  in  the  apparatus  recom- 
mended to  the  set-makers. 

Fred  Hill,  veteran  radio  amateur,  writer,  tech- 
nical editor  and  accomplished  engineer,  now  con- 
ducting several  important  departments  in  the 
technical  sections  of  this  magazine,  will  work 
with  Mr.  Rathbun  and  Mr.  Pearne  in  produc- 
ing the  best  construction  article  we  have  ever 
published. 


Why  The  "Radio  Age  Receiver"  Was  Designed 

THE  reason  for  thus  announcing  the  description  of  a  new  receiver,  down  to  the  last  detail, 
is  our  desire  to  impress  upon  you  that  this  feature  in  the  December  issue  will  set  a  new 
mark  in  the  presentation  of  "how-to-make"  information. 

We  publish  blueprints  and  many  other  helpful  illustrations  in  each  issue  of  Radio  Age. 
In  the  "Model  Receiver"  we  go  a  step  farther  and  offer  instructions  and  advice  in  selecting 
parts,  and  we  place  behind  this  receiver  the  name  of  our  magazine  as  evidence  that  it  has 
our  unqualified  approval  and  indorsement. 

To  Insure  Getting  the  December  Issue,  Order 

From  Your  Newsdealer  or 

Subscribe  Now! 


RADIO  AGE,  Inc. 


510  N.  Dearborn  Street 


Chicago,  Illinois 


*^ 


RADIO  AGE  for  November,  192 


The  Magazine  of  the  Hour  21 


Some  Interesting  Speculation  on 

The 

MAGNETIC 
THEORY 

of 

Radio 

Transmission 


RADIO,  since  its  birth,  has  been 
somewhat  of  a  mystery  to  the 
world.  Even  our  best  radio 
engineers  cannot  account  for,  nor  explain, 
many  of  the  results  obtained  in  radio 
transmission.  They  have  learned  that 
under  certain  conditions,  or  arrangement 
of  apparatus,  certain  results  are  obtained. 

Why  or  how  still  remains  a  mystery. 
Many  of  the  theories  and  laws  of  radio 
engineering  which  a  year  or  two  ago  were 
considered  up-to-date  and  practical  have 
been  proven  false  or  obsolete.      Radio  is 
making  rapid  strides  in 
spite    of    the     mystery 
surrounding   its    trans- 
mission. 

How  are  we  able  to 
transmit  messages  or 
music  half  way  round 
our  globe?  What  pre- 
vents them  from  being 
cast  into  space  and 
lost?  The  Heaviside 
theory  seems  to  be 
rather  generally  ac- 
cepted, but  at  its  best 
a  great  deal  is  left  to 
to  the  imagination. 
There  is  no  means  of 
proving  the  theory.  It 
is  not  the  intention 
here  to  disprove  that 
which  is  now  accepted, 
but  to  present  to  the 
radio  interested  public 
what  may  be  called 
"the  magnetic  theory 
of  radio  transmission." 


How  Impulses  Travel 

THE  Magnetic 
Theory  of  Radio 
Transmission  is  just  what  the  name  im- 
plies. The  magnetic  field  surrounding 
our  earth  is  the  medium  through  which 
our  radio  impulses  are  transmitted. 
Several  hundred  years  ago  the  magnetism 
of  the  earth  was  known,  studied,  and 
used.  Columbus,  in  his  voyage  of  discov- 
ery, used  a  magnetic  compass  as  an  aid  in 
sailing  his  three  small  ships.  In  recent 
years,  since  the  discovery  of  electricity,  it 
was  learned  that  a  current  through  a 
coil    of     wire   created    a    magnetic    field 


In  the  set  above  is  shoivn  the  proper  arrangement  oj  coils  to  prevent  inductive  coupling.  Engineers 
have  made  a  study  of  the  effect  of  the  magnetic  fields  of  adjacent  coils  upon  each  other,  and  efforts  have 
been  made  to  so  place  the  coils  in  the  receiver  that  the  effect  is  reduced  to  a  minimum.  Radio  ex- 
perience also  has  shown  that  better  results  are  obtained  in  reception  if  the  aerial  is  pointing  toward  or 
away  from  the  sending  station  sought.     This  is  especially  true  of  the  loop  aerial. 


around  the  coil  very  similar  to  the  earth's 
magnetic  field  and  which  attracted  the 
compass  needle  in  the  same  way  within 
a  small  area  surrounding  the  coil.  Any 
magnetic  field  constructed  by  man  is 
very  small  when  compared  with  the 
magnetic  field  of  the  earth,  the  extent 
of  which  no  one  knows.  We  do  know, 
however,  that  it  extends  into  the  earth 
and  into  the  air  beyond  any  point  pene- 
trated or  reached  by  man.  This  giant 
force    has    never    been    used    by    man, 


knowingly  at  least,  except  as  an  aid  in 
navigation  or  direction  finding.  The 
earth's  magnetic  field  has  the  same 
characteristic  as  the  field  surrounding  a 
simple  coil,  the  north  pole  of  which  is 
near  the  north  pole  of  the  earth  and  the 
south  pole  nearly  opposite  in  the  region 
of  the  southern  axis  of  the  earth. 

Since   the   advent   of   radio,   engineers 
have  made  quite  a  study  of  the  effect  of 
the    magnetic    fields    of    adjacent    coils 
(Turn  to  page  50) 


22 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


On  Inductive  Radio  Interference- 


CLEARING  UP  THE  ETHER 

Man-Made  Interference  a  Big  Problem  in 
Establishing  Qood  Radio  Reception;  How  Some 
Scientists  are  Classifying  Radio  Bug-Bears 


AN  ADDRESS  was  delivered  by 
Prof.  C.  M,  Jansky,  Jr.,  before 
L-  the  North  Central  Electric  Asso- 
ciation at  Duluth,  recently.  Prof. 
Jansky,  who  is  in  charge  of  radio  instruc- 
tion at  the  University  of  Minnesota, 
is  Chairman  of  the  Technical  Committee 
of  the  Northwest  Radio  Trade  Associa- 
tion and  Consulting  Engineer  of  the 
Gold  Medal  Station  WCCO.  About 
300  electrical  engineers  attended  the 
annual  convention  of  the  North  Central 
Electric  Association  which  is  the  North- 
west Branch  of  the  N.  E.  L.  A.  in  Minne- 
sota and  the  Dakotas. 

His   address  follows: 

"Within  the  past  ten  years  the  public 
lias  become  tremenduously  interested 
in  a  comparatively  new  field  of  electricity 
— radio  communication,  more  particu- 
larly radio  telephone  broadcasting.  This 
interest  has  in  the  past  and  will  continue 
to  develop  problems  affecting  those 
interested  in  the  other  electrical  sciences 
in  common  with  those  interested  in  radio 
communication.  Not  the  least  of  these 
problems  is  the  problem  of  inductive 
radio  interference.  Inductive  radio  inter- 
ference may  be  defined  as  interference 
to  radio  reception  resulting  from  the 
operation  by  man  of  other  devices,  using 
or  attended  by  electrical  phenomena. 

"Radio  communication  is  carried  on 
by  the  aid  of  electro-magnetic  waves. 
Electro-magnetic  waves  are  generated 
by  high  frequency  alternating  currents. 
For  the  purposes  of  radio  transmission 
high  frequency  alternating  currents  are 
produced  in  the  familiar  antenna  system 
seen  at  any  broadcasting  station.  A 
fixed  relationship  exists  between  the 
frequencies  of  the  alternating  currents 
in  the  radiating  system,  and  the  wave 
lengths  of  the  electro-magnetic  disturb- 
ance produced.  Since  electro-magnetic 
waves  are  identical  with  light  waves,  and 
therefore  travel  with  the  velocity  of 
light,  this  relationship  is — wavelength 
in  meters  equals  299,000,000  divided  by 
the  frequency  in  cycles  per  second. 

"The  wavelengths  used  for  radio 
broadcasting  ranged  approximately  from 
200  to  600  meters,  that  is,  the  frequencies 
used  to  produce  these  waves  range  from 
1,500,000  cycles  per  second  down  to 
500,000  cycles  per  second. 

How  Frequencies  Are  Made 
"QINCE  the  frequencies  used  by  elec- 
*— '  trie  power  companies  and  by  elec- 
trical    communication     companies     are 
much   lower   than   those   used   for  radio 


communication,  it  might  seem  at  first 
thought  that  the  operation  of  other 
electric  equipment  could  not  possibly 
produce  wavelengths  within  the  broad- 
casting range.  This  would  be  true  were 
it  not  for  the  production  of  other  fre- 
quencies in  electrical  systems  by  the 
interruption  or  disturbance  of  those 
systems  from  one  cause  or  another.  Such 
interruptions  or  disturbances  may  cause 
the  generation  of  high  frequencies,  which 
may  be  radiated  as  electro- magnetic 
waves  at  the  point  of  generation,  or  may 
be  carried  as  electric  currents  along  the 
adjacent  wiring  and  radiated  from  other 
points  on  the  system.  Sometimes  the 
effect  of  the  disturbance  may  be  ac- 
centuated by  the  fact  that  the  distributed 
capacitance  and  inductance  of  the  wiring 
may  be  such  that  oscillatory  currents 
having  natural  frequencies  within  the 
broadcasting  band  exist  and  damped  sine 
waves  may  be  produced  at  these  fre- 
quencies. The  difference  between  radia- 
tion and  induction,  or  the  question 
whether  or  not  there  is  a  difference  be- 
tween them  will  not  be  discussed  here. 
The  effect  in  the  receiving  set  is  the 
same.  , 

"Many  assume  that  if  electrical  de- 
vices or  systems  produce  interference 
to  radio  reception  such  devices  or  systems 
are  not  operating  properly.  While  this 
may  be  true  in  many  cases  there  are  in 
common  use  today  many  electrical  de- 
vices the  normal  operation  of  which  will 
cause  tremendous  inductive  radio  inter- 
ference. An  excellent  example  is  the 
synchronous  motor  driven  high  voltage 
rectifier  used  with  X-ray  tubes.  The 
sparking  discharge  produced  in  this  device 
willinterfere  with  radio  reception  at  points 
within  a  radius  of  several  miles  although 
the  operation  of  the  rectifier  may  be 
entirely  satisfactory  from  an  electrical 
and  medical  standpoint.  The  above,  is 
of    course,    an    extreme    example. 

"Time  is  too  short  and  the  subject 
too  complex  to  permit  a  more  detailed 
discussion  of  the  sources  of  inductive 
radio  interference.  The  immediate  prob- 
lem is  the  co-ordination  of  effort  in  the 
determination  of  what  in  specific  cases 
is  causing  interference  and  its  elimina- 
tion or  minimization  after  the  source  has 
been  found.  In  Canada  every  receiving 
set  owner  must  pay  a  license  fee  of  $2.00 
per  year.  Because  of  this  fact,  the 
Canadian  Government  feels  under  obli- 
gation to  study  and  eliminate  radio  inter- 
ference wherevrer  possible.     Accordingly 


the  Canadian  Radio  Service  has  inter- 
ference squads  continually  at  work.  In 
our  own  country,  some  attention  has 
been  paid  to  the  elimination  of  inter- 
ference by  our  Radio  Supervisors.  How- 
ever, the  Department  of  Commerce  has 
been  criticized  by  some  for  the  small 
amount  of  work  which  they  have  done 
on  this  problem,  on  the  grounds  that  the 
Radio  Act  of  1912  under  which  Radio 
communication  is  regulated  does  not 
provide  for  the  licensing  of  receiving  sets, 
and  therefore,  the  Department  should 
not  concern  itself  with  anything  which 
does  not  directly  affect  transmitting  sets. 
"It  is  an  interesting  fact,  worthy  of 
special  emphasis,  that  more  study  of  the 
problem  of  inductive  radio  interference 
and  its  elimination  has  been  done  by  the 
privately  owned  Electrical  Public  Utili- 
ties, individually  and  collectively,  than 
by  any  other  agency.  This  fact  is  greatly 
to  the  credit  of  our  public  utilities  and 
is  added  proof  of  their  desire  to  give 
satisfactory,  efficient  service  to  the  pub- 
lic. However,  the  public  utilities  can- 
not- and  should  not  assume  the  entire 
burden   of  eliminating  interference. 

"I  firmly  believe  that  satisfactory 
results  cannot  be  obtained  without  the 
co-operative  aid  of  all  those  involved. 
This  problem  concerns  the  power  com- 
panies, telephone  and  telegraph  com- 
panies, electric  railway  companies,  elec- 
trical and  radio  dealers  and  jobbers, 
transmitting  radio  amateurs,  and  last  but 
not  least,  broadcast  listeners  themselves. 
I  can  best  describe  what  I  mean  by  co- 
operative effort,  by  giving  a  brief  des- 
cription of  radio  interference  now  being 
organized  in  St.  Paul  and  Minneapolis. 
"The  Northwest  Radio  Trade  Associa- 
tion is  an  organization  of  radio  dealers, 
jobbers,  manufacturers  and  others  in- 
terested in  radio,  which  has  been  in 
existence  for  only  two  years,  but  in  this 
time  has  grown  to  a  point  where  its  mem- 
bership includes  practically  every  radio 
dealer  and  jobber  of  importance  in  the 
Northwest.  A  full  time  paid  secretary 
is  employed  to  look  after  the  interests 
of  its  members  and  to  help  improve  radio 
conditions   generally. 

A  Step  Forward 
"TAST  spring  the  Association  under- 
-*-^  took  to  foster  the  organization  of  a 
Twin  City  Radio  Interference  Com- 
mittee for  the  purpose  of  co-ordinating 
work  on  radio  interferences.  The  mem- 
bership includes  representatives  from 
(Turn  to  page  53) 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


23 


.  !*Z,-iX}~ii±>Z-**u' 


Spanning  the 

U,  S,  with 

Low-Power 

Transmission 

A  Low-Power  Station  that 
Anyone  Can  Build  and  Which 
Provides  Maximum  Interest 


By  BRAINARD 
FOOTE 


IN  THE  days  when  radio  amateurs 
used  a  wavelength  of  200  meters 
the  spark  transmitter  was  the  most 
popular  and  almost  the  only  type  of 
equipment.  Communication  over  a  few 
miles  was  established  with  an  ordinary 
1  inch  spark  coil,  and  with  a  huge  and 
noisy  outfit  comprising  a  1  kilowatt 
transformer  and  a  rotary  gap,  distances 
up  to  a  thousand  or  more  miles  were 
occasionally  covered. 

The  application  of  the  tube  to  the 
sending  set  greatly  simplified  the  appar- 
atus and  reduced  the  power  necessary 
for  a  given  distance.  With  a  five  watt 
tube,  the  continent  was  spanned  once 
in  a  while  and  the  amateur  had  a  fairly 
reliable  outfit  for  night-time  DX  work. 
With  the  use  of  short  waves  nowadays, 
down  to  20  and  40  meters,  low  power 
tubes  "eat  up"  the  miles  with  startling 
ability,  and  five  watt  transmitters  today 
frequently  are  heard  one-half  way  round 
the  earth. 

The  five  watt  sending  set  is  usually 
operated  from  the  110  volt  alternating 
current  mains,  obtaining  both  its  fila- 
ment and  plate  voltage  from  this  source 
through  transformers.  The  plate  voltage 
is  best  rectified  to  approximate  a  direct 
current,  to  improve  the  transmitted  tone 
and  make  the  signals  easier  to  "copy." 

Still  Less  Power 

HOWEVER,  on  short  wavelengths, 
power  less  than  that  of  a  five  watt 
tube  is  surprisingly  successful.  The 
peculiar  thing  about  20  and  40  meter 
work  is  that  waves  sent  out  on  the  earth's 
surface  don't  get  very  far,  being  absorbed 
by  metal  objects,  hills,  houses,  wires  and 
the  like.  But  waves  which  are  sent 
upward  at  the  proper  angle  are  reflected 
by  the  Heaviside  layer  or  refracted  by 
the  upper  limit  of  the  earth's  atmosphere, 
as  different  theories  have  it,  and  come 
down  to  earth  at  distant  points  with 
their  initial  strength.  Thus  we  have  a 
condition  which  is  superb  for  distance 
Work — local  sending  stations  being  unable 
to  communicate  with  each  other  easily, 
whereas  distant  stations  are  received 
strongly.  For  short  distance  work  of  the 
order   of    1    to    50   miles,    however,    the 


longer  waves  between  150  and  200  meters 
are  superior. 

The  writer  is  going  to  give  a  brief 
description  of  a  low  power  station  he 
has  set  up  at  a  Summer  bungalow,  located 
at  Stanhope,  New  Jersey.  The  trans- 
mitting tube  used  is  a  single  C  301A, 
lighted  from  a  storage  battery  and  sup- 
plied with  plate  voltage  by  ordinary 
"Heavy-Duty"  "B"  batteries.  Five 
such  "B"  batteries  were  obtained  for 
the  plate  source,  making  225  volts  in 
all,  but  in  most  of  the  experiments  and 
communications,  only  three  of  these 
were  used,  making  135  volts.  The 
radiated  energy  is  extremely  minute, 
of  course,  but  reports  from  stations 
within  an  800  mile  radius  indicate  that 
such  slight  energy  gets  "out"  just  the 
same.  At  the  present  writing  only  a 
single  day's  work  is  included,  but  the 
few  stations  "worked"  listed  below  in- 
dicate that  a  single  "A"  tube  ruffles 
the  ether  to  an  appreciable  extent. 


c3XI  Sarnia,     Can. 
2ABA  New  York 

City 
8AFQ   Brockport, 

N.  Y. 
8NT  Buffalo,  N.  Y. 
8CSR  Portable 

Station,  Alliance, 

Ohio 


1UE  Wollaston, 

Mass. 
8DRL  Reliance, 

Ohio 
3AFT  Schwenks- 

.  ville,  Pa. 
2CVJ   Hartsdale, 

N.  Y. 
8DPL  Buffalo, 

N.  Y. 

In  contemplating  the  use  of  "B" 
batteries  for  plate  voltage  supply,  one 
might  inquire  as  to  the  life  of  the  bat- 
teries in  such  use.  When  more  than  90 
volts  is  applied  to  the  plate,  the  plate 
current  is  naturally  somewhat  higher 
than  in  ordinary  amplifier  use.  How- 
ever, in  C.  W.  transmission,  the  current 
is  not  drawn  continuously  from  the 
battery,  but  only  while  the  key  is  de- 
pressed. The  effective  drain  on  the 
batteries  is  therefore  probably  a  good 
deal  less  than  with  receiving  batteries, 
since  they  are  not  used  constantly  as 
in  reception,  nor  is  the  current  steadily 
drawn  when  they  are  used,  but  in  in- 
terrupted service.  The  dry  cells  thus 
have  an  opportunity  to  recuperate,  which 
is  not  given  them  in  receiving  set  use. 
The  same  amount  of  power  used  in  run- 


ning a  spark  coil  or  in  obtaining  voltage 
through  transformers  from  house  current 
would  be  much  less  effective  in  distance 
work,  for  the  simple  reason  that  a  pure 
continuous  wave,  as  results  when  bat- 
teries are  employed,  consists  of  a  steady 
stream  of  impulses  at  radio  frequency 
while  in  A.  C.  use  the  radio  frequency 
impulses  reach  a  maximum  periodically 
and  then  decline  to  a  low  point.  A  pure 
D.  C.  "note"  will  carry  much  farther 
than  an  A.  C.  note  of  even  more  power 
on  this  account.  All  the  stations  report- 
ing on  the  signals  gave  a  good  account 
of  the  signals,  stating  reception  as  "R5 
to  R6,"  meaning  signals  moderately 
strong  or  strong.  All  seemed  astonished 
when  informed  that  a  single  "A"  tube 
on  "B"  batteries  was  being  used  at  the 
writer's  station  3MT. 

Antenna  System 

r  1 1HE  aerial  in  use  is  absurdly  simple. 
-*-  A  counterpoise  four  feet  above  ground 
consists  of  about  35  feet  of  solid  wire, 
No.  12,  running  between  the  house  and 
a  low  tree.  A  mast  only  4  feet  high 
supports  one  end  of  the  antenna,  while 
the  other  end  runs  to  the  roof,  20  feet 
away.  The  lead-in  runs  to  the  mast 
and  measures  approximately  25  feet  to  the 
apparatus,  making  the  aerial.  45  feet 
long  in  all — a  single  No.  12  wire.  Results 
probably  would  be  better  were  the  aerial 
entirely  vertical,  running  to  a  higher  pole, 
This  will  be  tried. 

The  entire  receiving  and  sending 
hook-up  is  given  in  the  circuit,  showing 
how  the  same  "A"  and  "B"  batteries 
serve  for  both  purposes.  The  antenna 
is  employed  with  ground  for  reception, 
but  with  the  counterpoise  for  trans- 
mitting. This  particular  outfit  is  oper- 
ated on  40  meters,  and  the  description 
is  given  for  this  wavelength.  It  can 
easily  be  applied  to  20  meters  or  to  the 
80  meter  band  by  altering  the  coil  and 
condensers  described  for  the  other  wave 
length. 

The  changeover  switch  is  a  small 
double  pole  double  throw  switch  with  a 
porcelain  base.  It  is  connected  so  as  to 
light  the  receiving  tubes  only  when 
receiving  and  the  transmitting  tube  only 


24 


RADIO  AGE /or  November,  1925 


The  Magazine  of  the  Hour 


when  transmitting.  Of  course,  the 
receiving  tubes  may  be  kept  lighted 
during  transmission  if  one  wishes  to,  but 
the  key  clicks  are  so  loud  that  they  are 
annoying.  Moreover,  there  is  some 
saving  involved  by  turning  them  off 
when  sending.  Where  the  receiver  and 
transmitter  are  situated  some  distance 
apart  and  separate  aerials  are  used,  it  is 
possible  to  work  "break-in,"  that  is, 
to  receive  while  transmitting,  so  that  the 
other  communicant  may  break  in  and 
stop  the  sender  when  interference  is 
encountered  or  a  word  is  not  under- 
stood. For  simplicity,  in  this  simple 
circuit,  the  usual  send-receive  system 
is  given. 

The  transmitting  apparatus  is  located 
to  the  right  in  the  diagram.  The  set  itself 
employs  a  C  301A  or  UV  201A  tube, 
used  in  a  nonmetallic  and  low-loss 
socket.      The    rheostat    R-l    has    about 

15  ohms  resistance.  Coil  L-3  is  the  grid 
coil,  consisting  of  9  or  10  turns  of  No. 

16  wire  on  a  3  inch  diameter  tubing. 
The  turns  are  spaced  about  1-8  inch 
apart.  The  tuning  condenser  C-4  should 
be  a  very  small  instrument,  and  a  midget 
variable  condenser  is  just  the  thing. 
Its  maximum  capacity  is  about  .000022 
mfds.  A  regular  unmounted  variable, 
with  2  plates  left,  will  also  answer.  The 
plate  coil,  from  which  power  is  fed  to  the 
antenna  circuit,  is  L-2,  also  having  9 
or  10  turns  of  No.  16  wire  and  tuned 
by  a  similar  small  condenser  C-3.  C-6 
is  a  .001  mfd.  fixed  condenser  of  good 
make  for  insolating  the  plate  battery 
from  the  filament  through  coil  L-2. 

The  plate  current  is  supplied  through 
the  radio  frequency  choke  coil  RFC-1, 
which  is  a  piece  of  tubing  1  inch  in 
diameter  and  about  6  or  7  inches  long, 
having  150  turns  of  small  wire  (about 
No.  28)  wound  on  it.  The  turns  should 
be  slightly  spaced.  Coils  L-3  and  L-2 
must   be   at   right   angles   to   each   other 


for  zero  coupling,  and  may  best  be  placed 
on  opposite  sides  of  the  tube,  in  line,  but 
at  right  angles.  The  "open  oscillating 
circuit"  is  composed  of  the  antenna  and 
counterpoise  and  coupling  coil  L-l, 
together  with  two  variable  condensers. 
These  can  be  regular  17  to  23  plate 
condensers  used  near  zero  capacity,  or 
smaller  variables  (not  less  than  10  or 
11  plates,  regular  size).  L-l  has  from 
five  to  seven  turns  of  No.  16  wire,  spaced 
1-8  inch  and  wound  on  a  tubing  that 
willl  slip  inside  of  L-2  In  case  one 
hasn't  a  low  scale  radiation  ammeter, 
a  good  indicator  may  be  made  of  a  flash- 
light lamp  of  about  2.5  volt  rating,  dimly 
lighted  by  a  1.5  volt  battery,  with  a 
small  switch  for  opening  the  circuit. 
The  battery  partially  lights  the  lamp  and 
the  slight  amount  of  energy  radiated  is 
shown  by  a  noticeable  brightening  of  the 
bulb.  When  the  set  is  carefully  tuned  up, 
the  lamp  will  be  lighted  faintly  without 
the  "biasing"  battery.  In  tuning  the 
transmitter,  it  will  be  found  that  maxi- 
mum radiation  cannot  be  maintained, 
because  the  circuit  is  too  unstable  when 
adjusted  for  greatest  output.  Coil  L-l 
is  slipped  inside  of  L-2  to  provide  high 
percentage  of  coupling. 

The  set  may  be  tuned  by  listening  in 
on  the  receiver  (making  a  connection  from 
the  "A"  battery  plus  to  light  the  receiv- 
ing tubes)  and  using  only  45  volts  on  the 
transmitter.  When  the  wavelength  is 
within  the  40  meter  band  as  found  by  a 
strong  whistle  in  the  receiver,  the  volt- 
age may  be  increased  to  maximum 
without  altering  the  tuning  dials  of  the 
transmitter.  Then,  condensers  C-l  and 
C-2  are  varied  near  a  low  scale  reading 
until  radiation  is  shown.  If  the  antenna 
circuit  is  tuned  too  closely  to  the  maxi- 
mum point,  the  set  will  suddenly  stop 
oscillating  or  will  shift  wavelength  sud- 
denly. The  antenna  is  then  left  off  tune 
very  slightly,  so  that  the  same  brilliancy 


of  the  lamp  or  the  same  radiation  (in 
case  of  an  ammeter)  is  indicated  every 
time  the  key  is  pressed. 

Receiving  Set 

T^HE  receiver  is  the  usual  regenerator 
■*-  with  one  step  of  audio.  L-5  is  the 
primary  and  consists  of  1  or  2  turns  of 
No.  18  or  20  wire  wound  on  the  same 
tubing  as  L-6,  the  secondary,  with 
about  half-inch  clearance  L-6  has  9 
to  13  turns — if  as  many  as  13  can  be 
used,  so  muchTthe  better.  C-7  is  the 
tuning  condenser  and  should  be  a  small 
variable  as  described  for  C-4  and  C-3. 
A  regular  condenser  cut  down  to  one 
movable  and  one  fixed  plate  will  do  also. 
When  the  set  is  in  use,  and  the  40  meter 
band  is  tuned  in,  it  is  easy  to  tell  whether 
L-6  is  too  large  or  too  small  to  cover 
the  band  well.  If  C-7  is  small  enough, 
the  40  meter  band  will  require  about  one- 
half  to  two-thirds  its  scale.  L-7  is  the 
tickler  and  should  be  wound  on  a  form 
about  half  the  diameter  of  L-6,  or  1  1-2 
inches.  It  should  have  from  ten  to 
fifteen  turns  of  small  wire:  No.  28  will 
do.  C-8  may  be  a  regular  17  to  23  plate 
condenser  for  control  of  regeneration. 
There  should  be  sufficient  turns  on  L-7 
to  maintain  oscillation  with  C-8  near 
maximum.  If  no  regeneration  is  had  at 
first,  reverse  L-7.  C-g  is  the  grid  con- 
denser and  should  be  very  small.  An 
XL  Vario-denser,  made  for  neutralizing 
purposes  and  screwed  to  maximum 
capacity,  makes  an  excellent  low  capacity 
grid  consdenser  for  40  meter  work.  The 
leak  should  be  one  that  is  not  noisy  and 
of  about  4  megohms  resistance.  In  the 
case  of  the  transmitter,  the  grid  con- 
denser is  .00025  mfds.  and  the  leak  a 
regular  transmitting  leak  of  about  10,000 
ohms  resistance. 

The  radio  frequency  choke  RFC-2  for 
the  receiver  is  made  exactly  like  that  for 
(Turn  to  page  53) 


RFC-Z 


C-l  c-£ 

*3 


R-l 


Ct>ZL~ 


RFC- 1 


Kcr 


LOW     POWER.         C.W.     SYSTEM 


RADIO  AGE  for  November,  1925 


What  the  Broadcasters  are  Doing  25 


Radiol  "Prettiest  Announcer" 


JUNE  MARLOWE,  a  distinguished  actress  and  dramatic  reader,  has  been 
won  over  to  radio,  because,  as  she  expresses  it,   "It  is  so  vast  and  awe- 
inspiring."    She  puts  such  a  feeling  of  interest  in  her  radio  presentations 
that  her  listeners  acclaimed  her  from  the  start.    Recently  she  acted   as   an- 
nouncer for  an  entire  evening  at  Station  KFWB. 

(C.  Heightoo  Monroe  Photo.) 


26 


RADIO  AGE  for  November,  1925 


Wkat  tke 

Broadcasters 

are  Doing 


What  the  Broadcasters  are  Doing 


Story  of  KWKH  an  Example 
of  Perseverance 

FjOWN  in  Shreveport,  Louisiana,  in 
*-*  the  extreme  Northwestern  corner 
of  the  State,  where  Texas,  Arkansas  and 
Louisiana  meet,  there  is  a  city  called 
"Shreveport." 

The  community  having  for  its  assets 
three  very  important  industries,  viz: 
Oil,  lumber  and  cotton,  it  is  seldom  con- 
tinued prosperity  is  not  felt  in  this  city 
for,  as  a  rule,  one  commodity  is  always 
good,  even  if  the  other  two  are  suffering 
a  slight  depression. 

Doubtless  a  great  many  of  our  readers 
throughout  the  country  have  heard  at 
various  times  programs  from  KWKH — 
The  W.  K.  Henderson  Iron  Works  & 
Supply  Company,  Shreveport,  Louisiana. 
This  station  is  probably  the  only  one 
in  the  United  States  of  America  owned 
and  operated  by  a  concern  engaged  in 
the  iron  and  steel  and  manufacturing 
trade  and  the  history  of  the  acquisition 
of  this  station  by  the  W.  K.  Henderson 
Iron  Works  &  Supply  Company  provides 
an  interesting  story. 

Mr.  W.  K.  Henderson,  president  of 
this  Company — a  man  of  large  interests 
in  his  community,  in  addition  to  his 
other  activities,  is  President  of  the 
Chamber  of  Commerce  and,  visualizing 
the  great  benefit  in  an  advertising  way 
that  could  come  to  the  community,  be- 
came interested  in  the  local  station 
when  it  was  very  small,  of  low  wave- 
length, poorly  powered  and  under- 
financed. 

The  credit  for  the  origin  of  radio  broad- 
casting in  Shreveport  must  be  given  to 
W.  G.  Patterson,  who  operated  the  sta- 
tion first  of  all  with  a  very  small  set  and 
had  for  his  call  letters  WGAQ.  When 
this  station  was  about  to  be  discontinued 
for  lack  of  proper  finance,  Mr.  Henderson 
intervened  and  having  interested  the 
Hotel  Youree  and  the  Shreveport  Times, 
together  with  himself  and  Mr.  Patterson, 
reorganized,  refinanced  the  station  and 
started  it  off  on  a  better  footing.  In 
time,  however,  Mr.  Henderson  became 
so  much  interested  in  this  station  and 
its  possibilities,  he  decided  to  purchase 
the  interest  of  the  Hotel  Youree  and  the 
Shreveport  Times,  changing  the  call 
letters,  with  the  authorization  of  the 
proper  authorities,  to  KWKH,  increas- 
ing the  wavelength  to  273  meters  and 
increasing  the  power  to  something  over 
500  watts  and  is  now  contemplating 
increasing  the  power  to  a  greater  ex- 
tent. 


A  radio  editor  and  announcer — combined,  is  Corley 
TF.  Kirby,  of  WWJ,  Detroit.  With  such  a  fund  of 
knowledge,  Mr.  Kirby  "knows  his  stuff"  as  far  as  being 
up-to-date  in  radio  matters  is  concerned.  Added  to 
that,  he  has  an  unusually  clear  voice  for  announcing. 


WRR,  New  Station,  Opens 
in  Dallas,  Oct.  1 

WRR  is  the  municipal  station  of  the 
city  of  Dallas.  It  was  first  es- 
tablished in  1920  and  is  the  second  oldest 
broadcasting  station  in  the  world  and  the 
first  in  Texas.  It  was  closed  down  by 
order  of  the  Government  in  1925  because 
of  the  obsolete  equipment. 

The  City  appropriated  $6,000  toward 
new  equipment,  while  contributions  from 
citizens  brought  the  fund  up  to  §15,000. 

Modern  500-watt,  101  B  broadcasting 
equipment  is  being  installed  in  Fair  Park 
in  a  special  built  building  for  the  new 
station  and  two  150-foot  steel  towers 
are  being  built  for  the  station. 


Urbine  J.  Herrmann,  managing  direc- 
tor, and  Clayton  Irwin,  general  manager, 
of  the  New  York  Radio  World's  Fair  and 
the  Fourth  Annual  Chicago  Radio  Show, 
to  be  held  in  November,  are  shown  in  a 
friendly  pose  above  before  broadcasting 
greetings  to  the  radio  public  at  the  Fair  in 
New  York,  Monday,  September  14. 
(P.  and  A.   Photo) 


'Merry  Old  Chief"  Fitzpatrick 
Joins  WJR 

T^HE  "Merry  Old  Chief"  is  packing 
■"-  his  bag  and  good  cheer  and  moving 
Eastward.  He  is  leaving  the  Kansas 
City  Star's  station  where  as  one  of  the 
real  pioneers  he  helped  to  put  broad- 
casting on  the  map  and  during  October 
he  will  join  the  staff  of  the  new  Jewett 
station,  WJR,  of  Detroit  and  Pontiac, 
Mich. 

The  "Merry  Old  Chief,"  or  Leo  Fitz- 
patrick as  he  is  known  outside  the  radio 
world,  has  personality  that  has  endeared 
itself  to  millions  of  listeners-in.  To  him 
is  due  the  amazing  growth  of  that  popular 
radio  organization  known  as  the  Night- 
hawks.  There  are  now  250,000  of  them 
and  the  membership  keeps  on  growing. 
He  organized  the  Nighthawks  and  his 
merry  good  nature  has  been  the  food  on 
which  the  membership  grew. 

Mr.  Fitzpatrick  is  a  graduate  of  Kan- 
sas University,  a  newspaperman  of  many 
years  experience,  and  one  of  the  best 
known  radio  announcers  in  the  world. 
He  organized  the  radio  department  of 
the  Kansas  City  Star  and  has  been  in 
continuous  charge  of  the  station  there 
from  the  time  it  was  started  four  years 
ago.  He  is  president  ot  the  Central 
States  Announcers'  Association.  His 
radio  popularity  is  easily  understood 
when  you  read  the  following  description 
of  the  "Merry  Old  Chief."  He  wrote  it 
himself: 

"To  begin  with,  I  was  born  in  Kansas 
So  were  many  others — Carrie  Nation, 
'Bill'  White,  Henry  Allen,  Sockless 
Jerry  Simpson  and  sunflowers  and  grass- 
hoppers. 

"Early  in  life  I  became  a  broadcaster. 
My  mother  claims  the  distinction  of 
being  the  first  Nighthawk  that  I  kept 
awake  until  dawn  with  my  howling. 

"I  survived  the  first  eighteen  years 
and  decided  that  I  should  write  the  great 
American  novel  or  try  for  the  O'Henry 
prize.  So  I  took  up  journalism  by  en- 
rolling in  the  engineering  school  of  the 
Kansas  University.  Finally  I  landed 
on  The  Star.  When  I  started,  the  Star 
had  a  circulation  of  200,000.  It  has  now 
more  than  250,000,  in  spite  of  my  being 
here   all  the  time. 

"My  ambition  is  to  get  eight  hours 
sleep  all  at  one  time.  Aversions — alarm 
clocks  and  hook-up  fanatics.  Descrip- 
tion— five  feet  eight  and  one-half  inches 
perpendicular;  thirty-six  inches  circular; 
thirty  years  old." 


RADIO  AGE  for  November,  1925 


What  the  Broadcasters  are  Doing  27 


Why  do  They  Call  Him 
^    RADIO'S 
._  w  Luckiest 

Devil? 


The  years  may  pass,  but  Banks  Kennedy  still  retains  the  youthful  glo-u 
and  dynamic  personality.  Of  course,  lie's  only  27,  but  he's  a  "vet"  as 
far  as  broadcasting  goes.  Above  he  is  shown  at  the  console  of  the  mighty 
WOK  organ,  where  he  officiates  daily  from  the  Terrace  Garden  of  the  Hotel 
Morrison,  Chicago. 


HE  HAS  been  dubbed  "Radio's 
Luckiest  Devil,"  but  that  is 
truly  a  misnomer  for  Banks 
Kennedy,  radio  staff  organist  at  Station 
WOK,  Chicago.  For  if  '  anyone  ever 
worked  to  deserve  fame,  it  was  Banks 
of  the  silken  locks. 

Readers  of  RADIO  AGE,  and  espe- 
cially those  who  listen  in  on  Chicago 
stations,  are  all  familiar  with  Banks 
Kennedy's  music,  his  pianologues,  and 
his  foolish  monologues.  He  has  appeared 
over  nearly  every  station  of  importance 
in  Chicago,  and  vicinity,  and  also  at  a 
few  unimportant  ones.  But  the  real 
story  of  his  career — the  story  that  will 
prove  he  is  not  lucky — but  just  persever- 
ing, has  rarely  been  brought  to  light. 
It  is  because  Banks'  admirers  are  so  busy 
listening  to  his  dynamic  songs  and  organ 
recitals  that  they  never  find  the  time  to 
inquire  into  his  spotless  past. 

A  Small  Beginning 

T3ANKS  was  born  in  Tuskaloosa, 
-*-*  Alabama,  where  he  obtained  his 
southern  drawl  and  his  love  of  mint 
juleps.  It  was  at  the  age  of  five  that  he 
persuaded  his  mother  not  to  throw  away 
the  old  grand  piano,  but  to  put  it  in  the 
basement  for  him  to  play  with.    The  dear 


lady,  anxious  to  please  her  youngest 
son's  slightest  whim,  conceded  his  re- 
quest, and  before  he  reached  the  mature 
age  of  six,  Banks  had  composed  a  song, 
which  he  dubbed  "Ethel." 

Either  the  name  was  a  handicap  be- 
cause of  its  impression  of  tameness,  or 
Banks  couldn't  work  up  enough  enthus- 
iasm, for  the  initial  masterpiece  died 
aborning  and  Banks  decided  to  content 
himself  with  learning  to  play,  rather  than 
learning  to  compose.  At  that  time  he 
was  working  his  way  through  grammar 
school  by  delivering  groceries  at  the 
enormous  sum  of  four  dollars  (S4)  per 
week,  which,  however,  was  not  enough 
to  provide  for  his  modest  needs. 

So  Banks  made  it  a  custom  to  furnish  a 
musical  rendition  with  each  delivery  of 
groceries.  The  idea  functioned  better 
than  he  expected,  and  he  picked  up 
considerable  small  change.  The  reaction 
on  the  grocer,  however,  was  more  or  less 
disastrous,  for  the  musically  inclined 
customers  refused  to  buy  groceries  unless 
Banks  delivered  them  and  hesitated 
long  enough  to  play  "Narcissus"  once 
more. 

With  such  a  background  of  groceries, 
it  is  small  wonder  Banks  never  lost  his 
love  for  food.     When  our  correspondent 


Luck  Played 

No  Part  in  Banks 

Kennedy's 

Meteoric  Rise 

to  Fame  in 

the  Studio 

World 

By  HARRY  ALDINE 


called  upon  him  at  the  Terrace  Garden 
of  the  Morrison  Hotel,  Chicago,  where 
the  glass  studio  of  WOK  is  located, 
Banks  was  holding  true  to  his  boyhood 
by  surrounding  a  chicken  dinner. 

Banks  Objects 

F  DON'T  like  this  stuff  about  being  call- 
■*■  ed  'Radio's  Luckiest  Devil',"  Banks 
protested.  "Here  I've  told  the  natives  of 
Tuskaloosa  that  my  success  is  the  result 
of  years  of  hard  labor,  and  now  the  news- 
paper writers  say  I'm  lucky." 

"It's  probably  because  you  work  so 
little,  accomplish  so  much,  and  get  paid  so 
highly,"  we  interjected.  Banks  accepted 
the  explanation  and  attacked  another 
layer  of  fruit  cake. 

So,  aftera  victoriouscareeratthe  organs 
of  the  Tivoli  and  Capitol  theaters,  Banks 
is  now  back  in  radio's  arms  again,  broad- 
casting from  the  organ  and  the  piano 
three  times  a  day,  and  in  general  spread- 
ing good  cheer  and  apple  sauce. 

Once  he  wrote  a  song  called  "If  I  Can 
Arrange  It,"  and  the  best  explanation  of 
his  phenomenal  success  as  a  song  writer 
and  general  good  fellow  can  best  be 
expressed  in  one  phrase — "He  arranged 
it,  somehow." 


28 


RADIO  AGE/w  November,  1925 


What  the  Broadcasters  are  Doing 


'^s»'«2S 


The  American  Farmer  is  one  of  the  greatest 
— if  not  T  HE  greatest  factor  in  our  national 
life.  And  yet  the  radio  has  not  reached 
him  as  it  should.  This  article  tells  what 
an  extensive  survey  revealed  in  the  farmer 
market. 


VALUABLE  information  of  interest 
to  radio  dealers,  listeners  and  manu- 
facturers alike,  has  been  brought 
to  light  by  the  recent  survey  of  the 
farm  market  for  radio,  made  by  the 
Capper,  Farm  Publications,  of  Chicago, 
111.  The  area  covered  by  the  survey 
includes  a  50-mile  radius  of  these  four 
towns:  Lima,  Ohio;  Mason  City,  la.; 
Salina,  Kansas,  and  Wichita  Falls,  Texas. 
The  most  outstanding  point  in  the 
report  of  the  survey  is  the  discovery 
that  no  particular  type  of  store  is  the 
leader  in  selling  radio  to  the  farmer. 
"It  is  difficult  to  determine  the  desir- 
ability of  any  special  type  of  store 
from  the  standpoint  of  developing  farm 
trade,"  the  report  says.  "On  the  con- 
trary, it  seems  evident  that  the  develop- 
ment of  farm  as  compared  with  town 
trade  depends  entirely  upon  the  dealer 
himself,  regardless  of  whether  he  is  a 
music,  automobile,  special  radio  or 
hardware  dealer.  In  other  words,  any 
good  dealer  making  an  effort  to  sell,  has 
been  about  as  successful  in  developing 
farm  trade  as  any  other  type  of  dealer." 
Statistics     taken     from     the     survey 


Qetting  the  Farmer  to 
Buy  a  Radio  Set 

Only  One  Farmer  in  Forty 
Has  a  Receiver,  According 
to  Census  of  Big  Territory 

By  A.  O.  PROCTOR 


disclose  that  there  are  approximately 
five  sets  for  every  200  farmers,  which, 
if  it  may  be  taken  as  an  average,  for 
the  entire  country,  shows  the  farmer 
market  is  but  one-fortieth  saturated. 
The  report  also  discloses  that,  in  the 
area  surveyed,  there  are  1.3  dealers 
per  1,000  families  and  that  each  dealer's 
average  sales  per  1,000  families  were 
18.1. 

Volume  of  radio  business  done  by 
types  of  dealers — The  exclusive  radio 
dealer  is  evidently  by  far  the  most 
successful  in  building  up  a  volume  of 
business,  his  sales  averaging  very  much 
higher  than  any  other  class  as  a  whole. 
In  towns  over  10,000,  hardware  dealers 
achieve  the  second  largest  volume,  but 
in  towns  of  less  than  10,000,  electric 
appliance  dealers  are  substantially  more 
successful.  Practically  all  types  of 
dealers  in  all  sizes  of  towns  carry  parts, 
accessories  and  tubes.  Between  67 
per  cent  and  85  per  cent  of  their  total 
sales  were  in  complete  sets,  3  per  cent 
to  13  per  cent  in  parts,  and  5  per  cent 
to  11  per  cent  in  accessories.  It  is  very 
interesting  to  note  that  at  least  75  per 
cent  or  more  of  dealers  in  all  sizes  of 
towns    reported  the   business   profitable. 

Guaranteed  service  as  an  aid  to  sales — ■ 
Definite  guarantees  and  assurances  on 
the  part  of  the  dealer,  of  service,  is 
apparently  necessary  and  is  used  as  a 
sales  argument  in  91  per  cent  of  the 
sales.  Forty-nine  per  cent  of  sales 
required  follow-up  service.  Dealers  who 
are  most  generous  in  making  installa- 
tions and  giving  service  have  achieved 
the  largest  sales  volume  to  farm  families. 


When  present  set  owners  will  buy 
another  set — More  than  one-fourth  of 
the  set  owners  answering  this  question 
said  they  would  buy  another  set  soon. 
The  same  number  reported  they  would 
buy  within  less  than  a  year,  the  same 
in  one  or  two  years,  and  the  balance  in 
four  years.  Evidently  the  replacement 
of  sets,  if  this  data  can  be  depended  on, 
is  going  to  be  a  substantial  business. 
Since  investigators  reported  that  some 
dealers  were  already  giving  "trade-in" 
values  on  old  sets,  this  factor  must  be 
operating  quite  strongly  now  in  rural 
districts.  The  maximum  price  which 
present  set  owners  would  pay  if  they 
were  to  buy  a  new  set,  ranged  between 
S153   and   S190,   complete. 

Status  of  exposure  to  radio — Of  the 
408  non-radio  owning  farm  families 
interviewed,  29  per  cent  had  never 
listened  in.  The  balance  had  listened 
in  one  or  more  times.  Twenty-three 
per  cent  had  listened  in  frequently. 
Forty-six  per  cent  reported  they  had 
listened  in  on  radio  sets  in  their  own 
or  neighbors'  homes.  Fifty-four  per 
cent  reported  they  had  been  interviewed 
by  salesmen  or  had  priced  sets  them- 
selves. Thirty-three  per  cent  reported 
that  radio  salesmen  had  visited  them 
in   their   homes. 

When  non-owners  expect  to  buy — 
Nearly  one-half,  49  per  cent,  to  be 
exact,  report  that  they  anticipate  buy- 
ing a  set  within  the  next  twelve  months. 
Texas  led  by  far  in  this  figure,  82  per 
cent  expressing  a  determination  to  buy 
this  season.  Ohio  was  lowest,  about 
(Turn  to  page  52) 


What  Kind  of  Radio  Sets  Do  Farm  Customers  Demand? 


PRICE  REQUIREMENTS 

Per  Cent 

Under  $50 4.9 

$  50  100 ;..... 17.8 

$100  150 . .; 41.1 

$150  200 25.2 

$200  250 6.1 

$250  300 _ -.: 4.4 

Over  $300 2.6 

TUBE  REQUIREMENTS 

Per  Cent 

1  tube 2.4 

2  tubes 5.0 

3  tubes 16.4 

4  tubes 26.4 

5  tubes 42.2 

6  or  over 7.6 


AERIAL  REQUIREMENTS 

Per  Cent 

Outdoor 82.2 

Indoor 5.5 

Loop 6.8 

Enclosed 5.5 

KIND  OF  A  BATTERY 

Per  Cent 

Dry  cell 38.3 

Storage 61.7 

PLACE  OF  LOUD  SPEAKER 

Per  Cent 

Want  enclosed  in  set. 29.4 

PLACE  OF  BATTERIES 

Per  Cent 
Want  enclosed  in  cabinet 49.2 


RADIO  AGE /or  November,  1925 


What  the  Broadcasters  are  Doing 


29 


Out  Where  the  Newsboys  Sing! 


It's  hardly  necessary  to  tell  you,  but  the  above  gleaming  visages  belong  to  the  newsboys*  radio  quartet,  which  is 
one  of  KNX's  surprise  features  for  the  impending  radio  season.     Don't  they  look  as  though  they  could  wield  a 

lusty  lung? 

KNX  Adds  "Newsboys'  Quartet"  As  Latest  Radio  Feature; 
Ralph  L.  Power  Qives  Impressions  of  California  Radiodom 


RADIO  fans  who  tune  in  on 
Southern  California  broadcast  sta- 
tions with  any  degree  of  frequency 
know  that  they  can  expect  almost 
anything  from  stations  in  and  around 
Los  Angeles.  Of  course,  they  have  their 
set  musical  menus  via  the  ether  waves, 
but  they  are  always  offering  something 
new  to  listeners. 

For  instance,  KFI  has  just  put  on  a 
series  of  talks  by  Dr.  William  E.  Bal- 
singer,  famous  plastic  surgeon  who  main- 
tains offices  in  Chicago  and  Hollywood. 
Dr.  Balsinger,  who  was  a  major  in  the 
reserve  during  war  days,  is  the  surgeon 
who  re-made  Dempsey's  nasal  appendage 
and  he  told  listeners-in  all  about  the 
new  nose.  Fans  had  heard  lectures  on 
topics  ranging  from  dandruff  to  birth 
control,  but  never  anything  about  how 
to  acquire  a  new  nose  as  fashions  in 
facial  expressions  change. 

The  Newsboy  Warblers 

THEN  there  is  the  Newsboys'  Quartet 
often  heard  from  KNX  in  Holly- 
wood. The  youthful  vendors  of  news- 
print have  warbled  their  Way  into  the 
homes  of  thousands  of  radio  families 
everywhere  and  their  graduation  from 
the  barber  shop  group  to  the  newsboys' 
quartet  could  never  have  been  accom- 
plished without  the  magic  of  radio. 
From  singing  on  the  street  corner  to 
their  present  engagements  at  banquets 
and  clubs,  made  possible  through  radio, 
was  a  big  forward  step  in  their  lives. 

Sefiora  Alma  Real  is  an  old  time 
favorite  in  the  grand  opera  field  and  she 
has  made  numerous  personal  appear- 
ances in  California  this  year,  notably  in 
the  Hollywood  Bowl  Concerts  and  at 
the  Theatre  of  the  Stars  at  Big  Bear 
Lake,  where  radio  KFXD  is  located  at 
an  elevation  of  more  than  a  mile. 

Sefiora    Real,    with    her   repertoire    of 


Mexican  and  Spanish  love  songs  has  won 
instant  applause  in  radio  fields,  and  she 
has  appeared  at  KHJ,  Los  Angeles,  many 
times.  Special  programs  for  the  Mexican 
Day  of  Independence  and  separate 
programs    of    Spanish    folk    songs    have 


After  seeing  Duane  Thompson,  film  star, 
in  this  pose,  we  don't  care  whether  she  can 
sing  over  radio  or  not.  She  appears  consis- 
tently at  KFI — but — what  were  we  saying? 


been  particularly  applauded  by  fan 
mail  and  personal  telephone  calls. 

Then  there  is  Louise  Santschi  Katzen- 
berger,  Swiss  yodeler,  who  brings  to 
receiving  sets  everywhere  the  plaintive 
melodies  of  the  Alps  region.  She  has 
been  a  favorite  at  KFWB,  Hollywood,  in 
solo  work  as  well  as  with  the  Tyroler 
Zither  Club,  whose  soft,  sweet  music 
has  brought  as  many  as  4,500  applause 
cards  for  a  single  concert.  The  organiza- 
tion has  gathered  together  a  unique 
library  of  original  melodies  from  their 
native  land  and  each  program  is  a  gem 
in  artistic  and  musical  setting. 

Mrs.  Katzenberger,  in  native  costume, 
takes  great  delight  in  singing  the  quaint 
yodel  songs  and  the  soft  lullabies  brought 
to  us  from  the  land  across  the  sea. 

The  poet  laureate  of  the  Los  Angeles 
police  department  is  Sergeant  Cyrus 
Johnson,  of  the  Hollywood  station,  and 
he  is  a  frequent  orator  at  KNX.  As  a 
purveyor  of  romantic  sonnets  and  tales  of 
romance,  Officer  Johnson  has  made  an 
enviable  record  and,  while  he  remains  a 
guardian  of  the  law  by  necessity  he  is  a 
poet  at  heart  and  radioland  gains  thereby. 

Duane  Thompson  Enters  Radio 

\  ND  of  course  you  can  hear  any 
-£*•  number  of  film  and  stage  stars  talk 
or  present  some  kind  of  musical  talent 
from  Southern  California -transmitting 
stations. 

Duane  Thompson,  one  of  filmland's 
celebrities,  has  entertained  from  various 
Los  Angeles  stations.  Others  who  have 
entertained  from  the  film  colony  include 
Lew  Cody,  Walter  Hiers,  Creighton  Hale, 
Renee  Adoree,  Lewis  Stone,  Monte 
Blue,  Percy  Marmont,  Marie  Prevost 
John  Bowers,  Marguerite  de  la  Motte. 
Johnny  Fox,  Jr.,  Baby  Peggy.  Carmel 
Myers,  Katherine  McGuire  and  scores  of 
others  equally  as  well  known. 


30 


<L 


RADIO  AGE  for  November,  1925 

The  Only  "Mammy" 
Writer  Born  in  Dixie! 


What  the  Broadcasters  are  Doing 


Jumping  from 

LAW 

to  JAZZ 

It's  a  Long  Jump, 

According  to  Charlie 

Qarland 


(~^  HARLIE  GARLAND,  writer  of 
.  blues  and  popular  songs,  radio 
-^  musical  comedy  producer,  movie 
organist,  baritone  and  pianist,  and  pro- 
gram and  studio  director  of  radio  station 
WBBM— 

That's  the  best  introduction  we  can 
think  of  regarding  the  young  man  in  the 
horn  rimmed  specs  and  "soup  and  fish" 
who  controls  the  goings  on  over  WBBM's 
microphone.  Incidentally,  however,  it 
may  be  of  interest  that  Charlie  is  the 
only  known  writer  of  southern  melodies 
that  ever  came  from  the  Dixie  country. 

Charlie,  in  fact,  was  born  in  Water 
Valley,  Miss.,  where  mammies  are 
mammies,  front  porches  are  galleries  and 
ordinary  sweet  potatoes  are  yams. 
This  vvas  in  1894  and  he  stayed  there 
until  he  grew  up  and  was  lured  up  no'th 
by  a  jazz  band. 

If  it  hadn't  been  for  the  jazz  band, 
however,  he  might  have  been  a  lawyer. 
Despite  the  fact  that  he  could  read 
music  before  he  knew  his  A  B  C's,  and 
could  play  the  piano  when  he  started  to 
school  at  the  age  of  eight,  in  what,  even 
the  neighbors  admitted,  was  an  entertain- 
ing way,  the  future  that  was  planned  for 
him  called  for  Blackstonc  and  a  lot  of  him. 


Charlie  Garland  appears  staid  and  dignified  only  when  posing  for  photo- 
graphs like  the  above.  You  ought  to  see — and  hear — him  when  he  directs 
WBBM's  famous  "Nut  Club"  every  Sunday  at  midnight. 


\  FTER  graduating  from  high  school  at 
-^*-  17,  Garland  entered  the  University 
of  Mississippi  and  studied  law  for  two 
years.  He  failed,  however,  to  find 
romance  in  musty  briefs,  citations  and 
life  began  to  loom  in  his  mind  as  an 
endless  path  of  subpoenas  and  amended 
petitions  to  make  more  definite  and 
certain. 

He  left  the  legal  profession  flat  and 
became  leader  of  an  orchestra  known  as 
the'  Grunwald  syncopators,  indirectly 
starting  his  trek  north.  After  the  orches- 
tra made  quite  a  name  for  itself  in  the 
south,  Charlie  joined  the  regular  army 
in  1916,  and  was  assigned  to  the  rank  of 
the  155th  Infantry. 

In  1917  he  was  commissioned  a  second 
lieutenant,  and  after  a  rather  eventful 
army  career  he  was  discharged,  and  de- 
cided to  give  the  business  world  another 
whirl.  This  time  he  tried  selling  life 
insurance.    The  "whirl"  was  short. 

In  1919  he  married  Miss  Lela  Mercier, 
of  McComb,  Miss.,  and  came  to  Chicago 
where  he  took  up  movie  organ  work. 
He  gained  considerable  reputation  at  this 
and  in  1921  heard  the  call  of  the  radio. 

After  appearing  over  KYW  and  several 
other  local  stations  he  became  connected 


DO  YOU  WANT  SPEECHES  OR  MUSIC? 

RADIO  AGE  wants  to  know  whether  its  readers  agree  with  Charlie 
Garland,  Program  Director  of  WBBM,  in  his  contention  that  radio  programs 
should  be  at  least  95  per  cent  musical. 

If  you  agree  with  Mr.  Garland,  or  take  exception  to  his  views,  you  can 
use  the  pages  of  RADIO  AGE  to  air  your  ideas.  Just  send  us  your  viewpoint 
and  we'll  print  the  best  arguments — pro  and  con — in  an  early  issue. 

Which  shall  it  be — Music  or  Speeches— jazz  or  farm  talks — educational 
or  amusing  discourses?  Take  your  pen  in  hand  NOW  and  start  the  sparks 
a-flyingl 


with  WBBM  in  1925  and  remained  there 
since.  He  was  appointed  studio  director 
at  WBBM  in  June,  this  year,  and  has 
just  been  made  program  director. 

In  addition  to  his  other  variated 
activities,  Mr.  Garland  has  left  a  trail  of 
popular  song  hits  behind  him.  Some  of 
his  latest  are  "Sweet  Mother  Mine," 
"Want  a  Little  Love?"  and  "Mississippi 
Blues,"  the  latter  being  the  twentieth 
that  he  has  published. 

The  ability  to  sing  in  rich  baritone, 
and  the  nimbleness  of  his  fingers  over  the 
piano  keys,  has  made  Charlie  better 
known  to  the  radio  fans  of  the  country 
than  the  average  studio  or  program  direc- 
tor. He  does  his  own  stuff  as  well  as 
directing  others. 

Radio  Comedies,  Too! 
UTS  latest  contribution  to  radio  is  a 
*-■*-  series  of  radio  musical  comedies 
which  he  is  writing  to  be  put  on  the  air 
over  WBBM.  The  productions — each 
45  minutes  long — will  be  adapted  espe- 
cially to  microphone  effects  and  be  "pro- 
duced" over  WBBM. 

Garland,  incidentally,  is  the  instigator 
of  an  interesting  experiment  being  carried 
out  over  WBBM — a  newly  inaugurated 
rule  that  the  program  must  be  95  per- 
cent musical  and  entertainment. 

"The  rule  means  just  what  it  says," 
said  Charlie.  "Basing  our  actions  on  the 
requests  and  written  desires  of  fans  we 
are  barring  all  lengthy  "educational" 
talks  and  addresses.  Anything  in  the 
line  of  talks  that  go  on  over  our  "mike" 
must  be  short  and  snappy,  in  the  nature 
of  'spot'  information  or  authoritative 
opinions  voiced  by  nationally  accepted 
authorities."  ~ 

Garland's  hobbies  are  golf  and  swim- 
ming and  a  young  son. 


RADIO  AGE  for  November,  1925 


Wliat  the  Broadcasters  are  Doing  31 


Are  You  Temperamental? 


Radio  Stars,  More 

Than  Any  Other 

Class  of  Public 

Entertainers, 

Are  The  Hardest 

to  Handle 

SAYS  GEORGE  GRAHAM 


(Witzel  Photo) 

Of  all  radio  stars,  Raquel  Nieto,  coloratura  radio 
soprano,  has  a  right  to  be  temperamental,  for  it  is 
her  temperament  that  makes  her  performance  un- 
usual— different,  and  refreshing. 


TEMPERAMENT!  It  Is  the  bug- 
bear of  the  stage — the  movies — 
business — and  everywhere  that  high 
strung  personalities  can  be  found.  But 
nowhere  is  it  more  evident,  more  harder 
to  cope  with,  as  Willis  Arnold  used  to 
say — than  in  this  intricate  game  of  radio 
broadcasting. 

David  Belasco  can  dismiss  the  tem- 
peramental actress  who  refuses  to  put 
the  proper  fire  in  the  soul-kiss  bestowed 
on  the  Barrymore  playing  opposite  her; 
or  Griffith  can  always  get  another  cinema 
performer  to  take  the  place  of  the  sulking 
Valentino.  And  even  in  the  best  adver- 
tising agencies,  those  outstanding  exam- 
ples of  business  efficiency,  the  long-haired 
copy  writers  find  themselves  perusing 
the  want-ad  columns  following  an  unwise 
burst   of   temperamental    disagreement. 

Radio  Stars  Can't  Be  Bossed 

RADIO  entertainers,  however,  can  do 
as  they  please.  There  are  enough 
of  them  to  sink  a  good  sized  ship,  and 
yet  each  is  so  confident  of  finding  a 
place  to  broadcast  his  or  her  wares,  that 
the  slightest  provocation  on  the  part  of 
the  studio  director  causes  a  sudden 
flareup  and  an  equally  sudden  departure 
on  the  part  of  the  "hurt"  artist.  As  a 
result,  a  studio  director,  careless  with  his 
comment,  might  find  himself  at  the  begin- 
ning of  a  three-hours'  program  with  noth- 
ing but  the  staff  accompanist  on  hand. 
It  has  been  known  to  happen,  and  it  is 


happening  nightly  in  radio  studios  where 
tact  does  not  prevail.  Announcers  and 
directors  are  known  to  be  among  the 
"transient"  class  of  employment,  for 
they  possess  an  uncanny  ability  to  lose 
their  positions  with  amazing  rapidity; 
chiefly  because. of  their  untimely  remarks 
to  the  tender  feelings  of  artists  who 
think  they  are  good  and  will  never  be 
convinced  that  they  aren't. 

One  of  the  best  examples  of  handling 
temperament  can  be  seen  in  the  case  of 
Miss  Raquel  Nieto,  coloratura  soprano 
with  the  Chicago  Opera  Company,  the 
San  Carlos  Opera  Company,  and  others. 
She  appears  over  nearly  all  the  Western 
radiophones,  such  as  KFI,  KGO,  KNX, 
KOA,  WBAP  and  others  too  numerous 
to  mention.  And  because  the  facts  of 
her  temperament  have  been  broadcast 
far  and  wide,  directors  of  the  stations 
where  she  appears  are  forewarned  of  her 
coming  and  treat  her  accordingly — which 
is  successfully. 

Miss  Nieto  is  not  purposely  tempera- 
mental, such  as  the  majority  of  self- 
styled  radio  stars.  She  gained  her 
temperament  by  birth,  as  you  will 
discern  by  her  French-Italian  name. 
Unusual  as  it  may  seem,  she  considers  her 
temperament  as  a  valuable  asset,  for, 
as  she  pu  s  it,  she  "really  means"  the 
words  of  a  song  when  she  aims  them  at 
the    microphone.      Temperament    is   her 


excuse  for  having  a  fiery,  passionate 
expression  in  her  musical  renditions. 
Without  temperament,  her  songs  would 
be  listless,  uninteresting  and  mechanical. 

And  directors  and  announcers  cater  to 
her  whims — for  she  is  really  a  great 
artist — by  giving  her  soft  lights,  soft 
music — an  absence  of  spectators,  and  a 
general  atmosphere  of  refinement  and 
quiet.  It  takes  very  little  effort  on  the 
part  of  the  station — and  it  makes 
Mile.  Nieto  feel  at  home. 

"If  a  few  more  announcers  would 
adopt  the  policy  of  broad-mindedness  in 
handling  artists,  there  would  be  less 
fiareups  and  broken-up  programs,"  ac- 
cording to  Pat  Barnes,  announcer-director 
of  WHT.  "These  artists  are  furnishing 
free  programs,  so  the  best  the  station 
can  do  is  to  cater  to  their  temperaments." 

Pat  Barnes,  more  than  any  other  an- 
nouncer, perhaps,  has  known  what  it  is 
to  be  temperamental,  and  it  is  this 
common  bond  of  feeling  that  causes  him 
to  sympathize  with  temperamental  artists 
and  treat  them  as  they  should  be  treated. 

"Temperament  is  usually  inborn  or 
unconsciously  assumed,"  Pat  explained, 
and  it  should  be  handled  as  a  malady  and 
not  as  a  disgusting  condition.  I  have 
tried  to  follow  that  policy  in  arranging 
my  artists,  and  I  am  proud  to  say  that 
temperamental  outbursts  are  a  thing  of 
the  past  at  our  station." 


What  the  Broadcasters  are  Doin- 


32  RADIO  AGE  for  November,  1925 

A  Real  Task  Confronts  Mr.  Hoover 


Annual  Radio  Confab 
to  be  Called  this  Win- 
ter Must  Over-ride 
Industry's  Obstacles 

BY  CARL  H.  BUTMAN 


THE  remarkable  growth  of  radio 
during  the  past  rive  years  was 
eulogized  by  Secretary  of  Com- 
merce Herbert  Hoover  last  month, 
when  he  spoke  through  Stations  WRC, 
WJZ  and  WGY,  in  conjunction  with  the 
National  Radio  Exposition  in  New  York. 
During  the  course  of  his  talk  Secretary 
Hoover  announced  he  would  probably 
call  the  Fourth  Annual  Radio  Confer- 
ence some  time  during  November.  He 
admitted  he  was  fully  aware  of  the  im- 
portance of  the  problems  confronting 
the  Conference,  and  urged  the  American 
radio  public  to  pay  a  patriotic  interest 
in  the  outcome  of  the  Conference. 

The  high-lights  of  Mr.  Hoover's  ad- 
dress follow: 

Radio— Its  Influence  and  Growth 

Radio  has  already  become  so  imbedded 
in  American  life  that  we  forget  that  the 
development  of  this,  great  scientific 
discovery  is  but  five  years  old.  Five 
years  ago  we  had  not  a  single  broadcast- 
ing station.  Today  we  have  over  572 
stations  and  probably  6,000,000  homes 
with  receiving  sets.  Five  3'ears  ago  the 
total  expenditure  in  the  industry  Was 
less  than  a  million  dollars  for  the  year. 
It  will  probably  exceed  $400,000,000 
this  year. 

I  do  not  believe  any  other  generation  in 
history  has  had  the  privilege  of  witness- 
ing the  progress  from  birth  to  adoles- 
cence of  a  discovery  so  profoundly 
affecting  the  social  and  economic  life 
of  the  peoples  of  the  world.  You  who 
attended  your  first  radio  expositions 
four  years  ago,  and  who  have  the  privi- 
lege of  being  present  again  tonight,  can 
see  marvelous  advances  in  the  art.  No 
other  invention  in  all  time  invaded  the 
home  so  rapidly  and  intrenched  itself 
so  securely  as  radio,  and  though  it  is 
still  far  from  maturity,  we  see  great 
advances  every  year.  Every  year  brings 
additional  scientific  discovery,  and  there 
follows  upon  it  new  invention  and  new 
application  to  service.  Your  annual 
expositions  serve  as  milestones  to  dis- 
close these  advances. 

Service  is  the  Keynote 

T^VERY  radio  activity  exists  finally 
-L^  and  lastly  to  serve  the  listening 
public.  The  keystone  of  the  industry  is 
to  maintain  their  interest  by  service. 
That  is  the  motive  of  the  broadcaster 


who  gives  us  better  programs  and  better 
quality  of  transmission,  and  is  the  ob- 
ject of  the  manufacturers  of  receiving- 
sets  that  they  should  give  more  reliable 
and  more  perfect  reception.  It  is  the 
object  of  the  Department  of  Commerce, 
which  has  the  very  difficult  job  of  keep- 
ing the  traffic  lanes  clear  so  that  the 
-  voice  over  the  radio  may  reach  the  lis- 
tener.- It  is,  therefore,  the  listener  in 
whom,  we  are  primarily  interested,  not 
only  as  an  industry  but  as  a  public  serv- 
ice. There  is  no  industry  so  dependent 
upon  public  good  will  and  interest.  I 
take  it  that  it  is  in  realization  of  the  fact 
and  the  wish  to  demonstrate  the  efficiency 
of  the  service,  both  present  and  to  come. 
Now,  it  is  often  said  that  the'listener  in 
the  United  States  receives  an  extraor- 
dinary service  without  paying  for  it. 
This  is  not  entirely  true,  for  he  pays  in- 
directly for  some  of  it.  But  in  the  fash- 
ion we  have  developed  the  organization 
of  radio  in  the  United  States  the  listener 
is  free  from  any  direct  charge  for  pro- 
grams. And  in  this  we  differ  from  the 
methods  of  foreign  countries  who  seek  to 
support  broadcasting  by  tax  on  the 
listener.  A  few  years  ago  much  anxiety- 
was  expressed  that  We  could  not  main- 
tain good  programs  of  entertainment  and 
the  delivery  of  public  information  with- 
out devising  some  system  of  tax  upon  the 
listeners.  It  has  been  my  aspiration  that 
we  should  keep  the  home  free  from  con- 
stant annoyance  of  any  attempt  to  assess 
the  cost  of  broadcasting  upon  each  re- 
ceiving instrument.  And  I  have  believed 
that  the  industry  would  develop  far 
more  rapidly  in  this  matter  than  if  we 
pursued  the  European  plan.  But  be- 
yond this,  support  by  taxation  means  a 
limited  number  of  government  controlled 
broadcasting  stations,  and  therefore  much 
less  variety  of  program,  much  less  com- 
petitive endeavor  to  please  the  listener 
and  above  all  constant  dangers  of  cen- 
sorship. 

I  am  today  confident  in  the  announce- 
ment that  our  policy,  that  there  shall  be 
on  the  air  every  broadcasting  station  for 
which  there  is  an  available  channel  and 
that  the  cost  shall  be  borne  indirectly 
or  by  public  service  institutions,  has 
proved  far  and  away  the  most  successful 
and  has  finally  settled  our  policies  for  all 
time.  It  is  a  great  accomplishment  and 
one   for   which    the   manufacturers,    the 


broadcasters,  and  even  the  staff  of  the 
Department  of  Commerce  deserve  some 
credit. 

But  whether  the  listener  pays  directly 
or  indirectly  or  not  at  all,  it  is  the  listener 
in  the  American  home  who  is  the  founda- 
tion and  furnishes  the  support  for  the 
whole  industry.  For  if  he  relaxes  or  his 
interest  fails,  the  whole  radio  structure 
"will  fall  as  quickly  as  it  has  grown. 

In  the  course  of  another  month  I 
am  summoning  the  Fourth  Annual 
Radio  Conference  in  Washington, 
in  which  all  elements — the  listeners, 
the  manufacturer,  the  broadcasters, 
the  radio  press,  the  distributor  and 
the  government — will  come  around 
a  common  table  for  the  fourth  time 
to  discuss  the  mutual  problems  of 
this  industry.  This  is  the  only  in- 
dustry where  everybody  agrees  that 
there  must  be  regulation.  Without 
regulation  we  should  have  complete 
chaos  in  the  air.  And  as  every  word 
by  radio  is  an  interstate  performance 
we  cannot  avoid  Federal  regulation. 
Attempt  to  regulate  rigidly  by  law 
without  the  cooperation  of  the  indus- 
try and  the  public  would,  I  believe, 
stifle  progress.  And  this  manner  of 
regulation  by  which  all  parties  sit  in 
for  solution  of  problems  is  unique 
in  our  relations  of  government  and 
industry. 

U.  S.  Leads  Them  All 

WE  are  far  in  advance  of  all  other 
countries  and  I  feel  it  has  been  in 
large  measure  due  to  the  cooperation 
worked  out  in  these  conferences.  But 
with  the  fine  cooperation  which  we  have 
developed  we  have  done  something  new 
in  the  whole  development  of  relations 
between  the  industry  at  large  and  the 
public. 

We  still  have  plenty  of  unsolved 
problems.  The  number  of  radio  channels 
is  limited.  They  are  already  so  over- 
crowded that  there  is  little  room  for  the 
new  comers.  They  jostle  each  other  a 
good  deal.  More  legislation  for  solution 
of  our  difficulties  is  being  frequently 
suggested  and  we  must  sooner  or  later 
determine  the  major  issue  whether  we  will 
continue  to  allow  every  new  broadcasting 
station  access  to  radio  paths  or  whether 
every  applicant  entering  must  first  show 
(turn  to  page  52) 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour  33 


More  Selectivity,  Less  Losses,  by 

Adding  Radio  Frequency  Stages 

By  JOHN  B.  RATHBUN 


THERE  are  a  number  of  advantages 
obtained  in  adding  one  or  two  steps 
of  radio  frequency  amplification  to  a 
detector  tube  outside  of  simply  increasing 
the  sensitivity  and  distance  getting 
qualities  of  the  set.  In  the  first  place, 
the  addition  of  one  or  two  stages  of  R.  F. 
amplification  increases  the  selectivity  of  a 
receiver  without  introducing  additional 
losses  as  is  the  case  with  the  average 
wave-trap  or  auxiliary  tuner.  Secondly, 
the  radio  frequency  stages  act  like  check 
valves  and  prevent  the  detector  tube 
oscillations  from  passing  out  to  the  aerial, 
thus  suppressing  the  emission  of  annoy- 
ing waves  and  squeals  in  a  neighboring 
receiving  set.  Thirdly,  the  great  degree 
of  amplification  attained  by  the  radio 
stages  permits  the  use  of  a  loop  aerial 
or  else  a  very  short  indoor  aerial  in  place 
of  the  more  common  outdoor  "flat  top" 
type. 

Radio  frequency  amplification  can  be 
applied  to  any  sort  of  a  detector,  a  crystal 
detector  or  vacuum  tube  detector  of  either 
the  regenerative  or  non-regenerative 
order,  and  to  each  of  these  detector  types 
it  imparts  the  virtues  of  sensitivity, 
selectivity,  and  reduced  radiation  from 
the  antenna.  It  should  be  noted,  how- 
ever, that  the  degree  of  selectivity  varies 
with  the  properties  of  the  detector  cir- 
cuit, the  selectivity  being  the  least  with  a 
crystal  detector  and  at  a  maximum  with  a 
regenerative  detector  just  as  with  the 
detectors  themselves  when  used  direct 
connected  to  the  antenna  in  the  usual 
way.  With  a  crystal  detector,  very  loose 
coupling  is  required  to  obtain  satisfactory 
selectivity,  and  the  same  is  true  of  the 
non-oscillating  type  sodion  tubes  and 
diode  tubes.  Regeneration  in  either  the 
detector  or  the  radio  frequency  tubes 
very  greatly  increases  the  selective 
properties  of  the  circuit,  and  when  more 
than  one  radio  frequency  stage  is  em- 
ployed, it  may  cause  excessively  sharp 
tuning  and  so  critical  adjustment  that 
the  set  is  difficult  to  handle. 

In  regard  to  sensitivity,  the  effect  of 
the  radio  frequency  tubes  is  to  amplify  or 


Copyright:  1925 


R.  R  Addition  Will 
Help  Suppress  Squeals 


magnify  the  weak  antenna  impulses 
before  they  reach  the  detector  tube  so 
that  the  detector  can  more  effectively 
rectify  the  incoming  impulses.  In  other 
words,  the  output  of  the  radio  frequency 
tube  forms  a  second  aerial  in  which  the 
radio  waves  are  much  stronger  than  in 
the  true  antenna,  and  with  the  detector 
connected  to  the  radio  frequency  output 
it  is  evident  that  stronger  signals  can  be 
obtained  at  the  detector,  that  is,  up  to 
the  saturation  point  of  the  tube.  Radio 
frequency  amplification  very  greatly 
increases  the  signal  strength  of  weak  dis- 
istant  stations,  but  has  very  much  Jess 
effect  in  amplifying  strong  signals  from 
local  stations  for  the  reason  that  the 
R.  F.  tubes  reach  their  saturation  point 
very  quickly  with  even  moderately  strong 
incoming  waves,  and  therefore,  any 
further  increase  of  the  antenna  impulse 
strength  will  have  no  effect  on  the  detec- 
tor output. 

A  Periodic  R.  F.  Stage 

ONE  of  the  simplest  radio  frequency 
stages  employed  is  the  "Aperiodic" 
or  "Untuned"  type  of  stage  shown  in 
Fig.  1  of  the  Blueprint  Section.  In  this 
case,  the  radio  frequency  tube  (RF1),  is 
connected  directly  to  the  antenna  and 
ground  with  the  grid  (G)  going  to  the 
antenna  without  any  attempt  at  tuning. 
When  connected  in  this  way,  all  wave- 
lengths are  amplified  indiscriminently 
within  the  range  of  the  circuit  constants 
and  the  selectivity  of  the  stage  of  course 
is  zero.  All  tuning  controls  must  be 
included  in  the  following  radio  stages, 
if  any,  or  in  the  detector  circuit  which 
follows  the  tube  (RF1).     The  output  of 


the  amplifier  is  at  the  plate  connection 
(P)  which  goes  to  the  succeeding  portions 
of  the  circuit. 

With  short  aerials  a  loading  coil 
(LC)  will  be  necessary  to  bring  the 
system  up  to  broadcasting  wavelengths. 
Generally  about  20  turns  of  wire  on  a 
three-inch  tube  will  be  sufficient.  This 
causes  no  losses  as  there  can  be  no  leak- 
age to  ground  through  the  distributed 
capacity. 

The  principal  advantage  of  this  sort 
of  radio  frequency  amplification  lies  in 
the  fact  that  all  of  the  energy  collected 
by  the  antenna  is  led  directly  to  the  grid 
of  the  tube  where  it  is  amplified  without 
loss,  and  this  is  of  the  greatest  importance 
when  working  very  weak  distant  stations. 
The  customary  losses  due  to  the  tuning 
inductances,  tuning  condensers,  etc.,  are 
eliminated  with  the  result  that  radio 
frequency  amplification  is  at  a  maximum. 

A  considerable  amount  of  radio  fre- 
quency energy  is  dissipated  by  leakage, 
losses  through  the  distributed  capacity  of 
the  coil  winding,  and  by  other  paths 
when  a  tuning  unit  is  used  between  the 
antenna  and  the  tube,  hence  by  the 
aperiodic  stage  we  conserve  every  bit 
of  the  precious  energy  for  amplification. 
The  output  of  the  tube  is  tuned  to  'Wave- 
length,  and  the  undesired waves  are  re- 
jected after  this  amplification  takes 
place,  hence  with  less  loss  and  better 
distance  than  can  be  attained  in  any 
other  way. 

By  means  of  the  coupler  or  air-core 
transformer  (CPLR)  in  Fig.  2,  the  first 
radio  frequency  stage  can  be  tuned  to 
the  desired  wavelength  in  the  usual 
manner,  thus  attaining  selectivity  from 
the  start.  The  primary  coil  (P)  is  con- 
connected  to  the  antenna  (ANT)  at 
one  end  and  to  the  ground  at  the  other, 
only  a  few  turns  of  wire  being  employed 
in  this  coil  so  that  the  lower  wavelengths 
will  pass  through  as  easily  as  the  long 
waves.  By  placing  (P)  in  inductive 
relation  to  the  secondary  coil  (S),  radio 
frequency  currents  are  induced  in  the 
(Turn  to  page  36)  ■-     ;-    ..';-. 


Original  Blueprints  on  Radio  Frequency  Stages  on  Pages  34,  35,  38  and  39 


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36 


RADIO  AGE  for  November,  1925 


{Continued  from  page  33) 
secondary  circuit  which  correspond  ex- 
actly to  those  in  the  antenna  and  primary 
coil,  and  from  the  coupler  the  impulses 
are  led  to  the  grid  of  the  tube  (G)  where 
they  are  amplified  and  then  pass  out 
through  the  plate  (P)  to  the  following 
circuit. 

A  variable  condenser  (C)  is  connected 
across  the  secondary  (S)  to  tune  the  radio 
circuit  to  the  required  wavelength.  The 
selectivity  or  sharpness  of  this  adjust- 
ment depends  largely  upon  the  degree  of 
"Coupling"  existing  between  the  two 
coils  (P)  and  (S),  that  is,  the  distance 
between  the  coils  and  the  percentage  of 
inductive  effect  resulting  from  this 
separation.  With  the  coils  close  together, 
the  tuning  is  "broader"  and  the  set  is  not 
so  selective  as  when  the  coils  are  separat- 
ed by  a  greater  distance.  For  example, 
with  coil  (P)  within  1-8  inch  of  coil  (S) 
it  may  require  20  dial  divisions  or  more  to 
tune  out  a  station,  but  when  the  coils  are 
separated  by  1-2  inch  or  more,  the  same 
station  can  be  completely  and  sharply 
tuned  out  by  turning  the  dial  through 
only  a  small  fraction  of  a  dial  division. 
This  adjustment  must  be  made  care- 
fully so  that  the  set  will  be  sufficiently 
selective  and  yet  not  unduly  sharp  or 
critical. 

Primary  coil  (P)  may  consist  of  from 
six  to  ten  turns  of  No.  24  D.  C.  C.  copper 
wire  wound  on  a  three  inch  cardboard 
or  bakelite  tube.  The  secondary  coil 
(S)  has  about  55  turns  of  the  same  size 
wire,  and  is  separated  approximately  1-2 
inch  or  5-8  inch  from  the  end  of  the 
primary  coil.  This  coil  is  tuned  through 
the  range  of  broadcasting  wavelengths 
by  a  0.00035  mf.  variable  condenser  (C) 
connected  across  the  secondary  coil  as 
shown.  There  are  other  and  more 
efficient  coils  than  this  on  the  market, 
but  the  dimensions  above  will  give  data 
for  a  home  built  coil  that  will  give  fair 
results. 

A  potentiometer  (PO)  is  shown  con- 
nected across  the  "A"  battery  circuit 
with  its  sliding  member  or  contactor  (s) 
connected  to  the  lower  end  of  the  coil 
and  variable  condenser,  but  this  is  not 
always  included  in  all  radio  frequency 
amplifiers.  Its  purpose  is  to  vary  the 
potential  or  voltage  on  the  grid  of  the 
tube  so  that  regeneration  can  be  con- 
trolled in  the  first  tube  and  hence  forms  a 
means  of  eliminating  howling  or  mushed- 
up  indistinct  reception  when  the  regenera- 
tion is  excessive.  Moving  (s)  upwards 
toward  (  — A)causesan  increasing  negative 
potential  on  the  grid  of  the  tube  which 
tends  to  reduce  regeneration  and  to  sup- 
press free  oscillations  and  howling. 
Moving  (s)  toward  (+ A)  gives  an  increas- 
ing positive  potential  on  the  grid  and 
increases  the  sensitivity  by  allowing  in- 
creased regeneration.  There  are  other 
methods  of  control  but  this  has  the  virtue 
of  simplicity  and  ease  of  operation  and 
installation. 

A  fixed  condenser  (K)  varying  from 
0.0005  mf.  to  0.006  mf.  is  connected 
between  the  slider  and  the  (—A)  wire  of 
the  potentiometer  to  reduce  the  inductive 
effect  of  a  wire  wound  potentiometer. 
It  bypasses  the  radio  frequency  current 
across  the  windings  of  the  potentiometer 
so  that  the  potentiometer  does  not  upset 
the  tuning  adjustments  every  time  that 
it  is  moved.  This  is  not  necessary  with 
carbon-pile  potentiometers  or  similar 
types  where  coil  windings  are  not  used. 
A  ground  connection  (G)  running  from 
the  (—A)  line  to  ground  is  always  an  ad- 
vantage and  is.  sometimes  an  absolute 
necessity.  It  greatly  reduces  any  ten- 
dency   toward    body    capacity    effect    in 


THE  RADIO   AGE 
RECEIVER 

The  surprise  of  the  season! 

After  months  of  research,  RADIO 
AGE  is  offering  its  own  set — any- 
one can  built  it,  and  it  will  positive- 
ly give  you  the  results  it  claims. 

Fully  illustrated  by  additional  blue- 
prints by  John  B.  Rathbun — All 
Parts  specified  by  trade  names — 


DECEMBER    RADIO    AGE 

ON  THE  STANDS 
NOVEMBER   15 


handling    the    variable    condenser    and 
usually  increases  the  amplification. 

By  connecting  the  output  (O)  to  the 
(ANT)  post  of  a  detector  set,  in  which 
a  two-circuit  coupler  is  employed,  and 
connecting  in  the  "B"  battery  to  the 
ground  post  of  the  detector  circuit  as  in- 
dicated by  the  dotted  lines,  the  stage  of 
radio  frequency  can  be  added  to  a  regen- 
erative set  with  good  results.  The 
coupler  of  the  detector  set  must  be  of  the 
two-circuit  type  with  a  primary  coil 
electrically  separated  from  the  secondary. 
Special  arrangements  will  be  required 
with  single  circuit  detectors  as  we  must 
avoid  making  any  connections  likely  to 
cause  circuits  in  the  "B"  battery  line. 
This  amplification  cannot  be  used  with 
ultra-audions  in  the  form  shown  nor  with 
similar  circuits  of  the  single  circuit  type. 

With  One  Stage  of  Radio 

THE  application  of  one  stage  of  radio 
frequency  amplifications  to  an  exist- 
ing regenerative  receiver  is  shown  more 
clearly  in  the  completed  diagram  of  Fig. 
3.  In  order  to  make  a  more  prominent 
distinction  between-  the  radio  frequency 
circuit  and  the  regenerative  detector 
circuit  to  which  the  radio  stage  has  been 
added,  the  radio  frequency  amplifier 
circuit  is  drawn  in  heavy  full  lines  while 
the  original  detector  circuit  is  drawn  in 
dotted  lines.  The  radio  frequency  circuit 
is  as  before  with  its  plate  output  post  at 
(O),  the  "B"  battery  connection  posts  at 
(  +  B),  and  the  "A"  battery  leads  at 
( — A)  and  (+A).  There  are  now  two 
wavelength  tuning  controls,  the  radio 
frequency  condenser  (CI)  and  the  origin- 
al detector  condenser  (C2)  which  of 
course  adds  greatly  to  the  selectivity  of 
the  circuits.  Audio  amplifying  stages 
can  be  added  at  the  detector  output 
marked  "Phones"  but  they  are  not 
shown  as  they  would  add  needlessly  to 
the  complication  in  describing  the  radio 
frequency  end  of  the  circuit. 

As  will  be  seen,  this  regenerative  detec- 
tor circuit  at  the  right  is  of  the  two 
circuit  coupled  type  with  the  addition 
of  a  third  coil  (TICK)  known  as  the 
"Tickler"  used  for  regeneration  in  the 
detector  stage.  The  primary  coil  is  at 
(P2)  and  the  secondary  at  (S2),  all  three 
coils  being  coupled  inductively  in  the 
usual  manner.  In  some  receivers,  the 
tickler  coil  (TICK)  is  adjustable  from 
the  front  of  the  panel  so  that  the  plate 
coupling  can  be  varied  by  turning  a  dial, 
while  in  other  receivers  the  tickler  coil 
is  wound  in  fixed  relation  to  the  other 
coils.  However,  this  makes  no  differ- 
ence in  the  connection  of  the  radio  fre- 
quency stage  as  long  as  the  primary  coil 


The  Magazine  of  the  Hour 

(P2)  is  electrically  independent  of  the 
secondary  coil  (S2).  If  the  primary  is 
connected  with  the  secondary  in  any  way, 
then  there  is  likely  to  be  a  short  circuit 
through  the  "B"  batteries  and  this  means 
trouble.  Carefully  examine  the  tuner- 
coupler  of  the  regenerative  circuit  that 
you  intend  to  use  for  the  detector  to  see 
whether  the  primary  coil  is  isolated  from 
the  rest  of  the  circuit,  for  in  many  cases 
you  will  find  a  short  connection  between 
the  primary  (P2)  and  secondary  (S2) 
as  at  (X)  which  must  be  removed  before 
going  further. 

At  (GC)  is  the  grid  condenser  and  at 
(GL)  is  the  grid  leak  which  need  not  be 
tampered  with  as  a  rule,  although  in- 
creasing the  value  of  the  leak  (GL)  is 
sometimes  advisable  in  order  to  secure 
stronger  signals.  Leaks  having  a  re- 
sistance higher  than  1.0  megohm  are 
seldom  used  in  straight  regenerative 
circuits  alone,  as  higher  values  increase 
the  tendency  toward  antenna  radiations, 
but  when  a  stage  of  radio  is  added  in 
front  of  the  detector,  this  can  be  increased 
to  2.0  megohms  with  improved  signal 
strength  and  with  no  danger  of  radiation. 
Independent  filament  rheostats  for  the 
radio  frequency  stage  at  (Rl)  and  for 
the  detector  at  (R2)  must  be  used  as  the 
detector  rheostat  adjustment  is  much 
more  critical  than  that  of  the  R.  F.  tube, 
particularly  when  a  fixed  tickler  coil  is 
used.  The  old  rheostat  used  in  the 
detector  circuit  should  not  be  changed. 

Plate  voltages  depend  upon  conditions. 
For  the  radio  frequency  tube  (RF1)  a 
"B"  battery  voltage  of  45,  67.5  or  90 
volts  can  be  used,  but  with  ordinary 
apparatus  45  volts  on  the  R.  F.  tube  is 
generally  best  for  bringing  in  distance. 
"B"  battery  potentials  of  67.5  and  90 
volts  may  give  stronger  signals  on  local 
stations  or  stations  at  a  moderate  dis- 
tance but  this  does  not  necessarily  indi- 
cate that  these  voltages  are  best  for 
distance.  Further,  high  voltages  make 
the  set  more  critical,  more  difficult  to 
tune  and  noisier,  so  that  we  should  use 
the  lowest  possible  voltage  that  will 
"bring  in  the  stuff." 

Usually,  the  detector  tube  (DET) 
works  best  on  22.5  volts  of  "B"  battery, 
the  voltage  being  obtained  by  tapping  the 
"B"  battery  as  at  (t).  Convenient 
taps  are  provided  on  most  "B"  batteries 
so  that  this  voltage  control  can  be  easily 
made.  In  any  event,  the  detector  volt- 
age should  not  be  higher  than  45  volts. 
A  full  90  volts  will  be  required  for  the 
audio  frequency  stages,  if  any,  so  that 
almost  any  combination  of  voltages  for 
the  R.  F.  and  detector  tubes  can  be 
carried  out  experimentally  up  to  90  volts 
without  purchasing  unnecessary  equip- 
ment. 

It  will  be  noted  that  the  tuner  unit  of 
the  regenerative  detector  circuit  now 
becomes  a  radio  frequency  transformer 
having  a  primary  coil  (P2)  and  a  second- 
ary (S2).  A  radio  frequency  transformer 
of  the  air-core  type  can  be  substituted 
for  the  tuner  unit  if  provision  is  also 
made  for  the  ticler  coil.  Some  form  of 
coupling  must  always  exist  between  the 
output  of  the  R.  F.  tube  and  the  detector 
which  will  prevent  the  plate  current  (0) 
from  being  directly  connected  to  the 
grid  of  the  following  detector  tube. 
If  the  "B"  battery  potential  is  applied 
to  the  detector  tube  in  any  way,  it  will 
give  such  a  strong  positive  bias  that  the 
tube  will  be  inoperative  or  paralyzed  as 
long  as  the  voltage  continues.  In  the 
case  of  single  circuit  regeneratives,  it  is 
usually  necessary  to  use  a  0.0005  stopping 
condenser  between  the  plate  of  the 
R.  F.  and  the  detector  tubes,  or  in  other 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


37 


cases  to  connect  the  outer  end  of  the 
grid  leak  to  the  (+A)  line  instead  of 
leaving  it  in  the  position  shown  by  Fig. 
3.  However,  nothing  of  this  sort  is  re- 
quired in  Fig.  2  where  the  plate  and 
grid  circuits  are  effectually  separated  by 
the  air  space  between  coils. 

In  cases  where  a  potentiometer  is  not 
desirable,  and  when  other  means  of  con- 
trolling self-oscillations  have  been  em- 
ployed, the  wiring  in  the  diagram  can 
be  altered  so  that  the  (—A)  line  at  (a) 
is  connected  directly  to  the  grid-return 
line  at  (b).  This  places  a  negative  bias 
on  the  first  tube  which  tends  to  suppress 
self-oscillations  but  which  may  interfere 
with  the  sensitivity  to  some  extent  by 
the  reduction  of  regeneration. 

Regenerative  Radio  Frequency 
Circuit 

By  applying  the  regenerative  principle 
to  the  radio  frequency  circuit,  a  very 
much  greater  amplification  can  be  ob- 
tained with  correspondingly  greater  sen- 
sitivity and  distance  getting  qualities. 
There  is  as  much  difference  between  a 
regenerative  and  non-regenerative  radio 
frequency  circuit  as  there  is  between  a 
regenerative  and  non-regenerative  detec- 
tor. The  radio  wave  from  the  antenna' 
receives  amplification  by  the  manner 
already  explained,  and  the  amplifier  out- 
put of  the  tube  is  then  returned  to  the 
grid  circuit  where  the  strengthened  im- 
pulse is  again  impressed  on  the  tube 
resulting  in  a  second  and  greater  ampli- 
fication. The  radio  frequency  waves  are 
greatly  intensified  before  they  pass  to 
the  detector  for  rectification. 

A  straight  tickler  (inductive)  feed- 
back can  be  applied  to  the  radio  stages 
as  in  Fig.  4,  where  (PI)  is  the  primary 
of  the  antenna  coupler,  (SI)  is  the  second- 
ary coil  of  the  coupler  and  (TICK)  is 
the  tickler  coil  feeding  plate  current  back 
to  the  secondary.  Plate  current  also 
passes  through  the  transformer  primary 
(P2)  through  which  the  radio  stage  is 
inductively  coupled  to  the  succeeding 
detector  or  to  a  second  stage  of  radio 
frequency.  When  the  tickler  coil  (TICK) 
is  adjustable  in  regard  to  the  other  coils 
a  very  close  control  of  the  regeneration 
can  be  had,  and  when  it  is  excessive 
through  any  means,  the  direction  of  the 
coil  can  be  suppressed  so  that  opposing 
or  "negative  feed-back"  is  had  which 
suppresses  the  free  oscillations  in  the 
circuit.  With  an  adjustable  tickler,  the 
potentiometer  (PO)  is  omitted,  and 
direct  connection  is  made  between  the 
(—A)  line  at  (a)  and  the  grid  return 
line  at  (b). 

With  a  fixed  tickler  coil  wound  directly 
on  the  same  tube  with  the  other  two  coils, 
no  such  feed-back  control  is  possible, 
hence  some  other  means  of  oscillation 
control  is  employed — generally  by  the 
combined  adjustments  of  the  rheostat 
(R)  and  the  potentiometer  (PO). 

Much  closer  control  of  the  oscillations 
is  had  by  the  revamped  "Weagent"  re- 
generative circuit  of  Fig.  5  where  a  tap 
(t)  divides  the  secondary  coil  (SI)  into 
a  tuner  and  a  tickler  coil.  Plate  current 
is  fed  back  into  the  lower  end  of  (SI) 
through  the  small  variable  condenser 
(C2)  while  the  variable  condenser  (CI) 
tunes  the  system  to  wavelength  as  before. 
Regeneration  is  very  accurately  con- 
trolled by  condenser  (C2)  which  regulates 
the  feed-back  to  the  grid  circuit.  Tap 
(t)  connects  with  the  (—A)  line  so  that  a 
negative  grid  potential  is  impressed  at  all 
times,  and  in  effect  this  is  the  grid  return 
circuit    as    well. 


SOMETHING  TO  BE 
PROUD  OF! 

— is  the  Radio  Age  Receiver,  to 
be  described  in  detail  for  our 
readers  in  the  December  issue,  out 
November  15.  Illustrated  with 
clear  blueprints  by  John  B.  Rath- 
bun. 

A  tuned  r.  f.  receiver  with  all  the 
latest  improvements  in  the  radio 
art. 

THE  LAST  WORD  in  Radio  Engi- 
neering— a  set  that  will  last  for 
years. 

Further  particulars  on  page  20, 
this  issue. 


Extended  Detector  Regeneration 

BOTH  radio  frequency  and  audio  fre- 
quency currents  exist  in  the  plate 
circuit  of  the  detector  tube,  and  on  pass- 
ing through  the  tube  the  radio  frequency 
currents  are  highly  amplified.  In  one 
very  effective  radio  frequency  circuit 
the  plate  current  from  the  detector  tube 
is  led  to  a  tickler  located  in  the  first 
stage  coupler  so  that  radio  frequency 
regeneration  is  obtained  together  with 
some  audio  frequency  feed-back.  The 
radio  frequency  tube  is  not  regenerative 
within  itself  as  shown  by  the  two  pre- 
ceding diagrams. 

A  typical  circuit  of  this  sort  is  shown 
by  Fig.  6  where  the  radio  frequency  tube 
is  located  at  (RF1)  and  the  detector  at 
(DET).  Plate  current  from  the  detector 
is  led  foward  to  the  tickler  (TICK) 
above  the  secondary  (SI)  of  the  coupler 
and  is  arranged  so  that  regeneration  is 
controlled  by  turning  the  tickler  in  rela- 
tion to  the  other  coils.  This  circuit  is 
very  efficient  and  is  highly  recommended 
where  one  stage  of  radio  frequency  is 
to  be  added  to  a  regenerative  set  or  for  a 
new  regenerative  set. 

A  radio  frequency  transformer  (RFT) 
couples  the  radio  frequency  circuit  to  the 
detector  with  the  primary  (P2)  in  the 
plate  circuit  of  (RF1)  and  the  secondary 
(S2)  connected  to  the  detector.  This 
transformer  can  be  of  the  fixed  self- 
tuned  type  or  else  the  typical  tuned  air- 
core  type  can  be  employed  with  the 
variable  condenser  (C2)  shown  in  dotted 
lines.  An  iron-core  (untuned)  radio 
frequency  transformer  is  desirable  at 
this  point  and  avoids  the  use  of  a  second 
tuning  control  when  a  high  degree  of 
selectivity  is  not  required.  Where  there 
is  a  great  deal  of  local  interference,  a 
tuned  transformer  with  the  condenser 
(C2)   may  become  necessary. 

A  potentiometer  (PO)  with  the  fixed 
bypass  condenser  (K)  affords  a  means  of 
oscillation  control,  and  it  will  be  noted 
that  both  tubes  are  provided  with  inde- 
pendent rheostats  (Rl)  and  (R2)  for 
the  individual  control  of  the  tubes. 
The  conventional  0.00025  mf.  grid  con- 
denser (GC)  and  the  2  meg.  leak  (GL) 
are  employed  as  before,  care  being  taken 
to  connect  the  filament  end  of  the  second- 
ary (S2)  to  the  (+A)  line  so  that  there 
is  a  positive  bias  on  the  grid  of  the  detec- 
tor. 

In  adapting  this  circuit  to  an  existing 
regenerative  set,  it  will  of  course  be  neces- 
sary to  move  the  coupler  and  tickler  of 
the  regenerative  circuit  to  its  new  position 
in  front  of  the  radio  frequency  tube 
(RF1).  The  radio  frequency  tiansformer 
(RFT)  is  then  substituted  for  the  coupler 


in  the  old  location  in  front  of  the  detector 
tube.  Phones  or  an  audio  amplifier  can 
be  connected  at  the  output  of  the  detec- 
tor, and  the  "B"  battery  is  shown  tapped 
at  the  point  (t)  to  obtain  22.5  volts  for 
the  detector  tube  although  the  full  45 
volts  can  also  be  used  successfully  with 
the  majority  of  tubes  now  on  the  market. 
The  output  is  cleaner  and  the  set  is  more 
stable  when  22.5  is  employed  on  the 
detector  plate,  but  the  volume  is  greater 
on  weak  signals  with  45  volts.  For  the 
radio  frequency  tube  (RF1)  a  plate 
potential  of  45  volts  generally  gives 
better  distance  reception  while  67.5  to 
90  volts  gives  better  volume  on  locals  and 
moderate  distances. 

By  adding  two  radio  frequency  stages 
instead  of  one,  much  better  distance 
getting  qualities  are  obtained  and  the  set 
is  made  more  selective  because  of  the 
greater  number  of  tuning  controls. 
This  is  the  arrangement  adopted  in  the 
popular  five  tube  radio  frequency  receiv- 
ers having  two  radio  frequency  stages, 
detector,  and  two  audio  frequency  stages, 
the  latter  being  for  the  purpose  of  gain- 
ing loud  speaker  volume.  Adding  radio 
frequency  stages  does  not  greatly  increase 
the  sound  volume  and  audio  amplifica- 
tion is  usually  necessary  with  any  number 
of  radio  frequency  tubes  except  with 
rather  strong  locals. 

Fig.  7  shows  two  stages  of  radio  fre- 
quency added  to  a  non-regenerative 
detector  circuit,  the  coupling  point  of  the 
radio  and  detector  circuits  being  at  the 
line  (X—  X)  and  indicated  by  the  small 
circles  representing  binding  posts  be- 
tween the  additional  stages  and  the  old 
set.  At  (1)  and  (2)  are  the  two  radio 
frequency  tubes  controlled  by  one  rheo- 
stat (Rl).  The  detector  tube  is  shown  at 
(DET)  with  the  usual  grid  condenser 
(GC)  of  0.00025  mf.  capacity  and  the  2 
megohm  grid  leak  (GL).  This  tube  is 
controlled  by  the  rheostat  (R2),  acting 
independently  of  the  R.  F.  tube  rheostat 
and  also  independently  of  the  rheostat 
used  for  the  audio  frequency  tubes  when 
an  audio  stage  is  used.  (Not  shown  in  Fig. 

A  single  circuit  coupler  (CPLR)  is 
used  for  tuning  the  antenna  circuit  to 
wavelength  instead  of  the  more  usual 
two  circuit  coupler  shown  up  to  this 
point.  It  consists  of  a  single  coil  of  wire 
connected  at  the  grid  (G)  and  (F)  ends, 
tapped  at  (a)  and  (b)  for  the  connection 
to  the  antenna.  By  connecting  at  (b) 
as  shown,  a  very  selective  condition  is 
had  while  connection  further  up  the  coil 
near  the  grid  end  at  (a)  broadens  the 
tuning  for  locations  where  there  is  not 
much  local  interference.  A  single  circuit 
coupler  in  the  first  stage  has  a  number  of 
advantages  when  three  tuning  controls 
are  used. 

(1)  The  circuit  is  more  stable  and  is  less 

likely  to  break  into  self-oscillations 
than  with  a  two  circuit  coupler. 

(2)  When  very  selective  transformers  are 

used,  the  use  of  the  single  circuit 
coupler  eliminates  the  split-hair 
dial  adjustments  and  the  sharp 
peaking  of  resonance  that  so  greatly 
interferes  with  the  reception  of  dis- 
tant stations. 

(3)  There  is  less  loss  with  the  single  cir- 

cuit type,  since  the  grid  of  the  tube 
is  directly  connected  to  the  antenna, 
and  distance  is  obtained  more  con- 
sistently. 
A   0.00035   mf.    variable   condenser   is 
connected  across  the  coupler  as  with  the 
secondary  of  the  two  circuit  coil,  and  a 
potentiometer    (PO)    provides    the    grid 
potential     variation     necessary    for    the 
control  of  self-oscillations  and  the  regen- 
(Turn  to  page  40) 


_   *;* 


WMWWM'ni 


by}, 
m   ™  5 

HE?  -. 


40 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


(  Continued  from  page  37) 
eration.  Across  the  slider  of  the  poten- 
tiometer and  the  (—A)  line  is  a  0.00S  mf. 
fixed  bypass  condenser  and  from  the 
inner  end  of  this  condenser  is  the  ground 
line  (g)  which  connects  the  (—A)  line 
to  ground.  This  first  stage  is  coupled  to 
the  second  radio  frequency  stage  by 
means  of  the  radio  frequency  transformer 
(RFT1)  with  the  primary  coil  (PI)  in  the 
plate  circuit  of  the  first  tube  and  the 
secondary  (SI)  going  to  the  grid  circuit 
of  the  second  radio  tube  (2).  The 
secondary  may  be  tuned  by  the  0.00035 
mf.  variable  condenser  (C2)  when  the 
transformer  is  of  the  tuned  air-core 
type,  or  this  condenser  can  be  omitted 
with  the  self-tuned  air-core  or  iron  core 
transformers  often  used  with  radio 
frequency  additions  in  this  sort.  Iron 
core  transformers  reduce  the  number  of 
controls  and  only  slightly  reduce  the 
efficiency  of  the  stages. 

When  two  stages  of  radio  frequency 
amplification  are  added  to  an  existing 
regenerative  circuit,  the  number  of  tuning 
controls  is  likely  to  be  inconveniently 
large  unless  the  iron-core  untuned  radio 
frequency  transformers  are  used  in  at 
least  one  stage,  and  this  is  particularly 
the  case  where  the  detector  circuit  is  of 
the  regenerative  type  with  a  tickler  con- 
trol and  two  variable  condensers.  Furth- 
er, the  small  fixed  untuned  transformers 
take  up  less  room  and  the  radio  frequency- 
cabinet  can  be  of  smaller  dimensions  than 
when  tuned  air-core  transformers  with 
their  variable  condensers  are  mounted 
on  the  panel.  With  a  good  iron-core 
transformer  there  is  not  much  less  in 
amplification,  but  the  circuit  must  have 
at  least  three  tuning  controls  (including 
those  in  the  detector  circuit);  for  the 
necessary  selectivity. 

The  output  of  the  second  radio  fre- 
quency tube  (2)  is  coupled  to  the  detector 
tube  (DET)  through  the  second  radio 
frequency  transformer  (RFT2)  which 
may  be  either  a  tuned  or  untuned  type. 
If  tuned,  then  the  secondary  (S2)  is 
tuned  by  the  0.00035  mf.  variable  con- 
denser (C3),  and  if  untuned,  this  variable 
condenser  is  omitted.  Note  that  the 
grid  leak  and  grid  condenser  are  con- 
nected into  circuit  just  as  with  the  fore- 
going circuits,  and  that  the  detector  tube 
is  fed  with  22.5  volt  "B"  battery  current 
as  before  explained.  From  45  to  67.5 
volts  is  preferable  for  the  radio  tubes 
>  (1)  and  (2)  rather  than  90  volts. 

Great  stability  can  be  added  to  this 
circuit  when  all  transformers  are  of  the 
air-core  tuned  type  by  the  use  of  grid 
neutralizing  condensers  shown  in  dotted 
lines  at  (NC),  and  the  circuit  is  also 
much  quieter  when  the  tubes  are  neutral- 
ized in  this  manner.  As  will  be  seen  from 
Fig.  7,  the  neutralizing  condensers  are 
connected  between  the  grids  of  the  radio 
frequency  tubes  and  suitable  taps  (N) 
in  the  transformer  secondaries.  When 
the  grids  are  neutralized,  the  potentio- 
meter (PO)  is  no  longer  necessary  and 
after  it  is  removed,  the  grid  return  line 
is  closed  by  connecting  the  (—A)  at  (e) 
to  the  ground  line  at  (d).  Owing  to  the 
high  resistance  of  untuned  radio  fre- 
quency transformers  and  the  damping 
influence  of  the  resistance  on  self-oscilla- 
tions, it  is  not  necessary  to  use  neutraliz- 
ing condensers  when  these  transformers 
are  in  the  circuit. 

The  output  of  the  detector  tube  can 
go  to  the  phones,  or  else  to  the  input  of  a 
two  stage  audio  frequency  amplifier 
when  loud  speaker  operation  is  desired 
on  distant  stations.  Connecting  a  loud 
speaker  to  the  output  of  the  circuit  shown 
will  give  soft  low  volumes  with  local 
stations   but   this   soon    falls    off   as   the 


distance  of  the  station  is  increased  so  that 
the  speaker  is  not  practical  without  audio 
amplification  at  distances  much  greater 
than  50  miles.  It  seems  hardly  necessary 
to  describe  the  audio  stages  in  detail  at 
this  point  for  they  have  been  published 
time  and  time  again  in  the  blueprint 
section  of  Radio  Age  as  well  as  in  other 
portions  of  the  book. 

While  the  detector  tube  (DET)  _  is 
shown  connected  up  as  a  non-regenerative 
yet  no  changes  are  introduced  into  the 
circuit  if  it  is  supplied  with  a  tickler  coil 
mounted  in  inductive  relation  to  the 
secondary  coil  (S2),  as  shown  in  the 
right  hand  dotted  portion  of  Fig.  3. 
This  introduces  another  control,  but  if  a 
fixed  untuned  transformer  is  used  at 
(RFT2)  in  place  of  a  tuned  transformer, 
we  will  still  have  three  controls  and  the 
set  can  be  easily  tuned  in  and  operated. 
With  a  movable  tickler  coil,  the  detector 
tube  will  no  longer  be  so  critical  to  fila- 
ment current  control  which  will  simplify 
matters  by  allowing  the  use  of  fixed 
resistances  at  all  points  in  place  of  the 
rheostats.  Three  Amperites  (one  at 
each  tube)  will  entirely  eliminate  rheo- 
static  control,  and  in  this  way  the  intro- 
duction of  the  tickler  adjustment  will 
effect  an  actual  saving  in  the  number  of 
controls. 

Complete  Two  Stage  R.  F.  Unit 

IN  FIG.  8  is  a  picture  diagram  of  a 
complete  two  stage  radio  frequency 
amplifier  adapted  for  use  with  a  detector 
unit.  This  is  the  same  circuit  as  that  in 
Fig.  7  with  the  exception  that  the  detector 
tube  is  omitted,  and  for  the  convenience 
of  the  reader,  both  drawings  are  lettered 
and  numbered  the  same  so  that  the  rela- 
tion of  the  parts  can  be  easily  followed. 
It  is  arranged  in  a  separate  cabinet  ready 
for  connection  to  an  existing  circuit  by 
means  of  output  and  battery  posts 
marked  at  the  left  of  the  set.  These 
posts  correspond  to  the  posts  in  Fig.  7 
shown  along  the  line  (X  — X). 

Both  the  coupler  (CPLR)  and  the 
first  radio  frequency  transformer  (RFT1) 
are  tuned  by  the  two  variable  condensers 
(CI)  and  (Cl),  both  condensers  having  a 
capacity  of  0.00035  mf.  The  second 
transformer  (RFT2)  is  an  untuned  type, 
iron  core  preferred,  which  couples  to  the 
detector  tube  in  the  following  unit.  No 
condenser  is  used  with  this  transformer. 
While  the  potentiometer  (PO)  is  used  for 
the  control  of  the  oscillations  in  the  radio 
frequency  stages  and  as  shown  on  the 
drawing,  it  will  be  possible  to  use  one 
neutralizing  condenser  connected  to  the 
first  tube  (1)  in  place  of  the  potentio- 
meter. My  advice  is,  to  use  the  poten- 
tiometer at  least  for  a  while,  unless  you 
are  rather  skilled  in  adjusting  neutralized 
circuits. 

There  are  many  ready-made  com- 
mercial coils-  more  suitable  for  use  than 
the  solenoid  types  shown  at  (CPLR)  and 
(RFT1)  but  these  low-loss  coils  cannot 
be  easily  made  at  home.  Examples  of 
these  coils  will  be  found  in  the  advertise- 
ments of  the  makers.  However,  for  the 
benefit  of  those  that  prefer  to  "roll  their 
own,"  the  dimensions  of  the  coils  are 
shown  in  Fig.  8.  They  are  wound  with 
No.  26  D.  C.  C.  or  No.  24  D.  C.  C,  with 
eight  turns  on  the  primary  and  55  turns 
on  the  secondary  of  transformer  (RFT1). 
The  coupler  (CPLR)  is  a  continuous  coil 
tapped  at  the  16th  turn  (b)  and  also  at 
the  30th  turn  (a).  These  tapping  points 
will  generally  give  a  sufficient  range  of 
selectivity  under  ordinary  conditions, 
but  there  is  no  reason  why  more  taps 
cannot  be  provided — say  at  every  tenth 
turn  or  so.  When  once  the  proper  tap 
point  is  found  for  the  connection  of  the 


antenna,  the  adjustment  is  fixed  for  that 
particular  locality  and  no  further  change 
is  needed  at  this  point.  The  tubes  are  3 
inches    in    diameter. 

Straight-line-wave-length  or  straight- 
line-frequency  condensers  add  much  to 
the  ease  of  tuning,  especially  in  bringing 
in  stations  in  the  200  meter  band  of  wave- 
lengths. There  is  more  space  between 
such  stations  when  measured  on  the  cir- 
cumference of  the  dials,  and  their  is 
more  opportunity  of  tuning  stations  out 
that  lie  within  a  few  meters  of  each  other. 
Vernier  type  dials  capable  of  very  close 
adjustments  are  now  almost  a  necessity. 

Either  the  201A  type  of  tube  or  the 
"199"  can  be  used  successfully,  but  the 
storage  battery  tube  201A  gives  the 
maximum  results.  Being  used  for  radio 
frequency  amplification  they  are  not  ■ 
particularly  critical  to  filament  current 
and  can  be  used  with  fixed  resistances  of 
the  amperite  type  in  place  of  the  rheo- 
stats. 


Twenty  Grand  Opera  Stars 
On  the  Air 

Radio  fans  throughout  the  United 
States  are  now  able  to  tune  in  regularly 
on  some  twenty  grand  opera  stars  and 
orchestras  of  international  note  through 
arrangements  made  by  A.  Atwater  Kent 
with  a  New  York  musical  bureau  con- 
trolling these  artists  and  the  American 
Telephone  and  Telegraph  Co. 

Starting  on  Sunday  night,  October  4th, 
WEAF  and  a  chain  of  the  affiliated 
stations  put  the  first  of  this  series  of  high- 
class  concerts  on  the  air  at  9:15  p.m. 
Eastern  Standard  Time.  The  appearance 
of  these  concert  artists,  all  well  known 
internationally,  will  continue  every  Sun- 
day night  from  WEAF,  New  York  during 
the  present  radio  season.  It  is  also  hoped 
that  many  will  sing  and  play  from  other 
stations  located  farther  west  and  south, 
a  little  later  in  the  year. 

It  is  Mr.  Kent's  idea  to  demonstrate 
for  the  radio  fans  what  can  be  done 
toward  better  radio  programs,  being  the 
first  step  of  the  general  movement  toward 
a  greater  radio  season,  and  perhaps  con- 
tinuous radio  service  for  the  listeners 
throughout    the    country. 

The  list  of  artists  already  signed  up, 
many  of  whom  will  appear  on  early 
Sunday  night  programs,  is  as  follows: 
Louise  Homer,  contralto;  Mabel  Garrison, 
Soprano;  Frieda  Hempel,  Soprano;  Maria 
Kurenko,  Soprano  of  Russia;  Florence 
Austral,  soprano  of  Covent  Garden, 
London;  Julda  Lashanska,  soprano;  Anna 
Case,  soprano  of  the  Metropolitan  Opera 
Company;  Reinald  Werrenrath,  baritone; 
Edward  Johnson,  tenor  of  the  Metropoli- 
tan Opera  Company;  Albert  Spalding, 
violinist;  Alexander  Brailowsky,  pianist; 
the  London  String  Quartet,  England;  the 
State  Symphony  Orchestra  of  New  York, 
and  Paul  Althouse  and  Arthur  Middleton 
of  the  Metropolitan  Opera  Company. 

Other  artists  who  will  be  heard  on  the 
air  provided  permission  for  broadcasting 
can  be  secured  include  the  following: 

Subject  to  permission  from  the  Victor 
Talking  Machine  Company;  Mme.  Ernes- 
tine Schumann-Heink,  Cecilia  Hansen, 
Margaret  Matzenauer,  Olga  Samaroff, 
Emilio  de  Gorgoza,  Kathryn  Meisle,  of 
the  Chicago  Civic  Opera  Company  and 
Giannini,  of  Europe. 

Those  subject  to  the  Brunswick 
Company,  are  Joseph  Hofmann,  world's 
greatest  pianist;  Allen  McQuhae  and 
Mario  Chamlee. 

Subject  to  permission  of  the  Metropoli- 
tan Opera  Company  are  Lucrezia  Bori, 
Merle  Alcock,  Joan  Ruth,  and;  Marion 
Telva. 


RADIO  AGE  for  November,  1925 


Send  for  this 


41 


The  Magazine  of  the  Hour 


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42 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


Latest  Models  Displayed  at 
Chicago  Radio  Show 

THE  radio  industry  has  offered  an  abundance  of  new  receivers  and  other  apparatus  for  the  season  1925- 
26.  Many  of  these  have  been  displayed  at  the  National  Radio  Expositions  in  Chicago  and  New 
York,  during  the  past  month,  and  at  the  Radio  Word's  Fair  in  New  York.  Now  comes  another  show 
to  be  held  during  the  month  of  November  at  the  Coliseum  in  Chicago.  Even  more  developments  and  improve- 
ments will  be  shown  at  this  show,  and  a  few  of  the  latest  to  be  introduced  to  the  radio  public  are  shown  on 
this  page. 


THE  new  "Apex"  Super- 
Five,  with  built-in  loud 
speaker,  is  attracting  attention 
at  recent  shows.  It  is  the 
product  of  the  Apex  Electric 
Company  of  Chicago  and  is 
but  one  of  their  many  interest- 
ing    models    for     this     season. 


THE  "Miraco"  Ultra- 5  Re- 
ceiver, a  product  of  the 
Midwest  Radio  Corporation  of 
Cincinnati,  Ohio,  combines  the 
latest  innovation  of  engraving 
the  dial  readings  on  the  panel. 
With  "man-size"  dials  and 
attractive  general  appearance, 
this  receiver  presents  an  idea 
of  the  new  trend  in  receiver 
design. 


THE  Diana  "Big 
Six"  comes  in 
many  shapes  and  sizes, 
but  the  console  model 
shown  at  the  right, 
with  its  attractive  cab- . 
inet  for  batteries,  etc., 
has  proven  the  most 
popular.  When  closed 
the  entire  receiver  has 
the  aspect  of  a  dig- 
nified piece  of  fur- 
niture, and  when  open, 
as  shown  in  the  pho'to, 
it  harmonizes  with  any 
surroundings. 


THE  Logodyne  Big  Five, 
made  by  the  Kodel  Radio 
Corporation  of  Cincinnati,  is 
a  high  type  tuned  radio  fre- 
quency receiver,  enclosed  in  an 
Adam  Brown  mahogany  cabinet 
of  massive  proportions.  The 
stations  are  already  logged, 
and  the  panel  is  of  the  sloping 
variety,  engraved  in  gold  on 
Formica. 


/N  response  to 
readers'  re- 
quests, further  pic- 
tures and  descrip- 
tions of  new  re- 
ceivers to  be  intro- 
duced at  the  Chi- 
cago Radio  Show 
will  be  published 
in  the  Show  Section 
of  the  December 
Radio  Age,  out  No- 
vember 15. 


RADIO  AGE  for  November,  1925 


£tnd 
Hoolc'^TLtp^ 


The  Magazine  of  the  Hour  43 


<T>HE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  is 
•*•  contributed  by  our_  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points, 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


Conducted  by  Fred  Hill. 

IF  one  were  to  judge  from  a  casual 
perusal  of  the  radio  and  trade 
magazines,  it  would  appear  that  the 
doughnut  coil,  the  form  of  winding  old 
as  the  hills  in  the  telephone  game,  but 
its  radio  application  ■  fairly  new,  is  at- 
tracting quite  a  bit  of  attention  from  a 
host  of  manufacturers.  Quite  a  number 
of  the  sets  advertised  for  the  1925-1926 
market  are  announced  as  being  equipped 
with  the  doughnut  coils,  although  travel- 
ing under  many  different  names. 

The  single  or  double  control  also  seems 
to  be  getting  some  attention  and  efforts 
are  made  by  the  manufacturers  to  ar- 
range the  tuning  units  so  that  single 
control  will  work  out  smoothly  and 
accurately  along  the  waveband  covered 
by  the  different  type  of  receivers.  All  of 
which  seems  to  indicate  that  radio  fans 
cannot  be  far  from  wrong  in  following 
out  this  general  plan,  at  least  for  the 
sake  of  greater  simplicity  in  tuning  and 
the  greater  selectivity  afforded  by  the 
inductances  with  enclosed  fields.  In  our 
August  Pickups  and  Hookups  we  de- 
tailed the  description  given  by  George 
B.  Hostetter,  Box  325,  Freewater,  Ore., 
of  a  simple  means  of  making  the  toroid 
coil. 

Now  comes  H.  J.  Hughes,  of  2082 
East  Grand  Blvd.,  Detroit,  Mich.,  who 
elsewhere  in  these  pages,  presents  a  sketch 
and  a  description  of  the  method  in  which 
he  makes  his  doughnut  coils.  A  reading 
of  Mr.  Hughes'  description  and  that  of 
Mr.  Hostetter  will  probably  prove  very 
enlightening  to  the  radio  fan  who  wants 
to  take  a  fling  at  the  doughnut  coil 
construction. 

Readers  of  this  department  might  find 
interesting  dope  in  the  September  blue- 
print section  where  Mr.  Rathbun  gives 
audio  amplifying  circuits,  both  trans- 
former and  resistance  coupled.  Then 
in  the  October  number  he  shows  the 
single  and  double  controlling  of  doughnut 
tuning  units.  Taking  a  composite  of 
the  September  and  October  numbers  of 
RADIO  AGE,  the  reader  should  be  able 
to  fix  up  a  dandy  receiver  that  will  follow 
more  or  less  the  latest  practice  in  radio 
manufacture. 


The  data  given  by  H.  J.  Hughes, 
referred  to  above,  for  winding  doughnut 
coils,  follows:  Procure  a  piece  of  one 
and  an  eighth  inch  brass  tubing  ten 
inches  long.  Cut  a  slot  its  full  length, 
slot  to  measure  three-eighths  of  an  inch. 


CONTRIBUTORS 

CM.  Thomas 

Freight  Traffic  Dept.  N  and  W. 

Ry Roanoke,  Va. 

W.  G.  Bailey..... 

.1315  Davenport  Road ..... 

Toronto,  Can. 

Robt.  A.  DeVries 

114  8th  Ave 

.    New  York  City 

H.  J.  Hughes 

.2082  East  Grand  Blvd. ... 

Detroit,  Mich. 

A.  W.  Small..... 

..1210  12th  St.,  N.  W 

Washington,  D.  C. 

Paul  M.  Hayes 

DIAL  TWISTERS 

Pasadena,  Calif. 

Floyd  E.  Morris 

..Fort  Saskatchewan 

Alberta,  Canada 

Wm.  F.  Lauritzen ... 

.275  Highland  Ave 

Somerville,  Mass. 
...  Brooklyn,  N.  Y. 

Frank  Scudello 

.83  Bay  44  St....... 

George  B.  Jones,  Jr 

75  Maiden  Lane 

-  .New  York  City 

This  can  be  done  with  a  hacksaw  by 
placing  the  tube  on  a  board  and  nailing 
a  strip  at  both  ends  that  passes  through 
the  length  of  the  tube,  to  hold  it  down  on 
the  bench  while  cutting  and  also  prevents 
the  tube  from  binding  on  the  saw. 

After  slotting  the  tube,  drill  and  tap 
two  6-32  holes  in  it  to  hold  the  wire. 
Tie  one  end  of  the  wire  to  the  screw  and 
start  winding  your  coil  clockwise,  fasten- 
ing the  other  end  to  the  other  screw. 
Before  winding,  take  the  clips  C  and  CC, 
shown  in  Fig.  3,  and  solder  them  at 
either  end  of  the  tube  over  the  slot, 
keeping  the  slot  three-eighths  of  an  inch 
apart. 

After  winding  the  secondary,  which 
consists  of  about  225  turns  of  No.  22 
DSC  or  DCC  wire,  and  the  primary,  which 
ismadeof  20turnsof  the  same  wire  wound 
over  the  secondary,  unsolder  the  clips, 
take  out  the  screws  and  press  in  at  both 
ends  of  the  tube  to  release  the  coil. 
Take  a  piece  of  adhesive  tape  5-16  inch 
wide  and  bind  it  over  the  coil  through  the 
slot.  Then  bring  the  coil  around,  fasten 
the  ends  and  the  job  is  finished.  The  coil 
may  be  treated  with  a  little  airplane 
varnish,  although  untreated  will  do 
just  as  well. 

In  winding  the  primary  it  should  be 
wound  in  four  groups  of  five  turns,  as 
shown  as  the  places  marked  X  in  Fig.  3. 
This   is   so   the    primary    will   follow   the 


secondary  all  the  way  around  the  dough- 
nut and  give  coupling.  The  process 
related  above  may  be  repeated  as  often 
as  necessary  to  give  the  number  of  dough- 
nuts required. 


Another  r.  f.  unit  to  be  added  ahead  of 
a  standard  receiver  (providing  the  pri- 
mary and  secondary  coils  of  the  old  set 
are  thoroughly  isolated)  may  be  made 
from  the  diagram  shown  in  this  depart- 
ment, Fig.  1,  and  submitted  by  Robert 
A.  DeVries,  114  8th  Ave.,  New  York- 
City,  N.  Y.  LI  consists  of  45  turns  of 
22  DCC  spaced  5-8  inch  from  L  2  and 
wound  on  a  three  inch  tube.  L  1  con- 
sists of  15  turns  of  the  same  sized  wire. 
L  3  is  made  up  of  60  turns  of  22  DCC, 
tapped  at  the  fifteenth,  thirtieth  and  45th 
turn,  on  a  three  inch  tube.  The  variable 
across  LI  is  a  .0005  mfd.,  Rl  is  30  ohms. 
R2  is  a  variable  resistance.  The  two 
posts  at  the  extreme  right  of  Fig.  1 
should  go  to  the  aerial  and  ground  posts 
of  the  old  set.  (Be  sure  the  primary  of 
the  old  set  is  not  in  any  way  connected 
to  the  secondary.)  The  A  battery  con- 
nections may  be  carried  over  to  the  old 
set  so  the  two  units  function  off  the 
same  A  and  B  batteries. 


W.  G.  Bailey,  1315  Davenport  Road, 
Toronto,  Canada,  who  smashed  his 
collar-bone    and    has    been    laid    up    all 


44 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


\7  i_ 


lo-^W^ 


rw 


r\ 


■o <l 


■o  A 


\* — 


#6    ' 


6     6        6         6 

-  A   +■  -6     1" 


Fig.  1.  In  this  r.  J.  unit,  to  go  ahead  of  a  regular  set,  submitted  by  Robert  A.  DeX'ries, 
114  8th  Ave.,  New  York  City,  N.  Y.,  readers  may  find  a  solution  to  their  worries  about 
the  lack  of  signals.  The  variable  resistance  in  series  with  a  tapped  plate  coil  allows  the 
control  of  the  plate  potential  and  helps  prevent  undue  regenerative  effects  in  the  first  tube. 
The  description  is  given  elsewhere  in  this  department. 


Summer  as  a  result,  sends  in  the  dope 
shown  in  Fig.  2  which  is  a  loosely  coupled 
regenerative  set,  using  the  Weagant 
variant  for  control  of  regeneration  and 
oscillation.  The  primary  coil  consists 
of  10  turns  of  No.  24  DSC.  The  secon- 
dary is  a  straight  winding  of  60  turns  of 
the  same  sized  wire,  with  a  center  tap 
at  the  30th  turn,  which  goes  to  the 
filament.  The  wavelength  control  is  the 
capacity  from  end  to  end  of  the  coil 
and  is  a  .0005  variable.  The  regeneration 
control  which  runs  from  the  lower  end 
of  the  secondary  to  the  plate  of  the  tube, 
is  a  three  plate  vernier  condenser.  The 
tube  used  is  a  WD-11.  The  entire  set 
may  be  made  up  into  portable  form  and 
furnishes  good  results  under  normal 
conditions.  The  grid  condenser  is  .00025 
and  the  leak,  3  megohms. 


of  any  of  our  radio  family  has  ever  juggled 
the  filaments  of  a  burned  out  tube 
around  while  same  was  hooked  to  a  110 
volt  line.  We'll  say  we  did,  sometimes 
disastrously  and  sometimes  otherwise. 
Best  way  is  to  hook  it  to  your  battery 
and  then  lightly  tap  the  burned  out 
tube  against  your  palm.  If  you  are 
lucky  you  might  have  a  new  tube; 
otherwise  trot  down  to  the  store  and 
plunk  down  your  hard  earned  kale  for 
another  glass  bauble. 


Pardon  us,  gentle  readers,  but  we  like 
to  see  letters  like  the  following,  and  to 
think  we  have  deserved  them:  "Desire 
to  thank  you  for  back  numbers  sent  me 
due  to  various  changes  of  address.  You 
have  without  a  doubt  the  finest  publica- 
tion in  the  radio  field  and  I  am  particu- 
larly pleased  not  to  have  missed  any 
of  the  numbers."  The  writer  was 
George  B.  Jones,  Jr.,  75  Maiden  Lane, 
New  York  City,  N.  Y. 

!"  

i  Using  the  one  lunger  known  as  a  single 
control,  single  tube  set  Frank  Scudello, 
83  Bay  44  St.,  Brooklyn,  N.  Y.,  manages 
to  pull  in'the  signals  despite  the  Summer- 
time and  the  high  power  nest  in  New 
York. 


Wow — listen  to  this  one.  Its  from  C. 
M.  Thomas,  Freight  Traffic  Department, 
N.  and  W.  Ry.,  Roanoke,  Va.,  who 
relates  as  follows:  "Read  your  magazine 
regularly  and  must  say  it  is  the  best 
monthly  on  the  market  with  no  excep- 
tions. It  has  more  in  it  than  all  the  rot 
of  its  class  now  sold.  I've  been  reading 
your  pages  regularly  and  notice  most  of 
the  hookups  are  single  circuit  cr  the  like 
that     squeal     fearfully     and     make    the 


neighbors  say  things  entirely  un-holy. 
Would  suggest  you  publish  these  con- 
tribution diagrams  as  to  the  changing 
sets  so  they  won't  radiate.  There  are 
many  such  plans  now  published." 

Mr.  Thomas  then  tells  of  adding 
a  r.  f.  unit  to  his  receiver  with  an  in- 
crease of  about  25  per  cent  in  efficiency. 
The  department  this  month  has  a  scheme 
for  making  your  own  r.  f.  unit;  we  have 
also  published  these  ideas  from  time  to 
time,  but  it  is  a  Herculean  task  to  con- 
vert the  world  from  a  single  to  a  loosely 
coupled  circuit.  If  you  don't  believe  it, 
try  it  on  your  friends. 


Radio  fans  who  are  troubled  with 
emaciated  signals  in  the  last  stage  of 
their  amplifier,  or  else  who  are  bothered 
with  an  overloaded  last  stage,  might  do 
well  to  try  out  the  Radio  Corporation's 
latest  tube,  known  as  the  UX-112  which 
is  designed  for  use  in  the  last  stage  of 
audio  and  which  will  probably  be  equiva- 
lent, in  results  secured,  to  two  of  the 
201-A  type.  The  tube  has  an  oxide 
filament,  dull  emitter  type,  and  cer- 
tainly does  pep  up  your  signals  wonder- 
fully. We  have  noted  that  the  Daven 
Radio  Corp.,  has  also  placed  a  tube  de- 
signed for  last  stage  work  on  the  market, 
being  known  as  the  MU6.  The  use  of  a 
good  power  tube  in  the  last  stage  gener- 
ally recompenses  the  owner  for  his 
trouble,  in   increased   volume. 


Several  fans  have  written  this  depart- 
ment lately  for  a  good  soldering  flux  to 
be  used  with  rosin  core  solder.  Our 
method  is  to  take  about  a  half  glass  of 
grain  alcohol  and  dissolve  into  it  enough 
powdered  rosin  to  make  a  watery  paste. 
Use  this  paste  on  joints  to  be  soldered, 
just  a  little  dot  of  the  stuff  being  enough. 
It  will  clean  the  joint  well,  and  when  the 
iron  is  well  tinned  and  hot,  the  soldering 
job  can  be  made  a  thing  of  beauty  in- 
stead of  an  awkward  lump.  Use  wire 
rosin  core  solder.  For  the  meticulous 
solderer,  a  wet  rag  will  help  to  wipe  off 
(Turn  to  page  46) 


Rosary-like,  "The  hours  I  spent  with 
thee"  is  applied  by  William  F.  Lauritzen, 
Somerville,  Mass.,  to  the  pursuit  of  the 
wily  DX  with  the  result  that  his  one 
tuber  has  kept  him  hopping  from  ethereal 
pillar  to  post.  His  list  is  a  staggering 
one  and  would  entitled  him  to  the  button 
even  if  for  no  other  reason  than  the 
amount  of  energy  spent  in  compiling  it. 


Albert    W.   Small, 
W.   Washington,    D. 


1210    12th    St.,    N. 
C.   rises   to-  inquire 


Fig.  2.  Another  variant  of  the  Weagant  sent  in  by  W.  C.  Bailey,  1315  Davenport 
Road,  Toronto,  Canada,  who  uses  WD-11  tubes  and  gets  good  results.  Many  of  the 
Canadians  use  the  dry  cell  type  of  tube  on  account  of  their  economy  and  the  portability 
of  the  set.     The  description  of  the  circuit  is  found  in  these  pages. 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


45 


Jhe  ZlnitedJIchievement 
of  Jen  Radio  Engineers 

THE  DIFFERENCE  in  this  receiver  is  no  mere  superficial 
difference.  It  is  a  distinction  that  you  yourself  and  thousands 
of  others  made  in  discussing  the  "ideal  Receiver."  The  Hammar- 
lund-Roberts  is  a  "composite  receiver,"  the  individual  achieve- 
ments of  ten  leading  radio  engineers. 

Every  unit  in  the  Hammarlund-Roberts  Receiver  represents  the  highest 
attainment  of  a  leading  engineer.  The  transformers  were  selected  by  a 
transformer  engineer  familiar  with  every  reliable  make,  after  months  of 
experiment  and  trial.  The  condensers  were  similarly  determined  on  by  an 
engineer  whose  special  study  has  been  condenser  characteristics,  functions 
and  construction.  A  man  whose  whole  effort  has  been  on  resistance  research 
and  perfection  selected  the  resistance  units.  Even  the  smallest,  usually 
neglected  units,  were  made  the  object  of  scrutinizing  study.  Never  before 
has  so  much  extraordinary  thought  been  given  to  every  detail  of  a  receiver. 
This  combination  of  these  harmonizing  units  in  the  most  desirable  circuit 
is  a  receiver  that  is  truly  the  ultimate  of  five-tube  reception,  a  composite 
of  the  higher  ideals  in  radio. 

And  now — you  can  obtain  this  remarkable  Hammarlund-Roberts  Receiver 
for  LESS  than  the  price  of  any  factory  made  5-tube  receiver  on  the  market 
of  anywhere  near  equal  quality. 

Write  for  descriptive  folder. 

Hammailund  Roberts,  1182-D  Broadway,  N.   Y. 


if  amm  arlund     J 

oDerts 


(FOUNDATION     UNIT 

The  skeleton  or  foundation  for  your  HAMMAR- 
LUND-ROBERTS RECEIVER — bakelite  panel, 
engraved;  drilled  bakelite  sub-panel,  brackets 
and  wiring.  The  other  specified  parts  are  stand- 
ard and  can  be  purchased  from  any  &q  Ar\ 
reliable  radio  dealer     -----  ^,TU 


- 


CONSTRUCTION  BOOK 

Write   for  this  most  complete  book 
giving  complete  details  on  assembling,  wiring 
and      operating    the     Hammarlund- 
Roberts  Receiver  - 


25c 


*    Tested  and  Approved  by  EADIO  AGE    * 


46 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  How 


<? 


lit* 


<p\*     *A    * 

*<£ 

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Cc,~ 

Ij!!!;!;     5(ot  -^g" vtid*.                   ! 

H|Hll' 

III. .1,1 
II,, .1,1 

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F,*3 


Fig.  3.  The  sketch  shown  above  is  furnished  by  H.  J.  Hughes  and  shows  the  manner  of  winding  a  doughnut  coil.  B  is  the  end 
view.  Full  data  is  given  in  the  text  in  this  department.  This  data  and  that  published  in  the  August  number  should  enable  any  of  our 
readers  to  go  into  the  subject  thoroughly. 


the    joints    after    being    soldered    so    no 
traces  of  rosin  will  remain. 


Resistance  coupled  enthusiasts  will 
find  a  world  of  opportunity  for  experi- 
mentation in  the  use  of  various  values  of 
leak  resistances  for  the  first,  second  and 
third  stages  of  their  resistance  coupled 
amplifier.  For  this  purpose  a  handy 
clip  scheme  may  be  employed,  the  clips 
being  secured  in  sets  from  radio  dealers. 
The  clip  idea  may  be  used  for  the  coup- 
ling condenser  between  the  plate  of  one 
tube  and  the  grid  of  the  next,  the  value 
generally  used  being  .006  mfd.  Almost 
any  of  the  square  condensers  will  slip 
firmly  into  the  clips.  Then  for  the  re- 
sistances there  are  clips  into  which  you 
can  put  any  desired  value  of  resistor. 
The  use  of  a  bypass  across  the  first  100,- 
000  ohm  plate  resistor  is  advisable  and 
for  this  purpose  another  clip  may  be 
used.  Thus  the  whole  affair  can  be 
changed  in  value  at  will  and  without  the 
necessity  of  unscrewing  binding  posts  or 
unsoldering  lugs.  The  scheme  is  a  handy 
one  and  should  prove  of  real  benefit  to 
the  insatiable  radio  tinkerer.  We  ob- 
serve that  Daven  specifies  100,000  ohms 
for  each  of  the  plate  resistors  in  the  resis- 
tance coupled  amplifier,  while  the  grid 
biasing  resistors  are  one  megohm,  1-2  and 
1-4  meg  for  the  grids.  Others  have  found 
that  one  megohm  in  the  first,  a  half  in 
the  second  and  a  quarter  megohm  in 
the  third  tube  will  work  well.  Rathbun, 
in  his  recent  contribution  on  resistance 
coupled   amplifiers,   showed   the.   1    meg, 


1-2  meg  and  1-4  meg  for  the  grid  biasing. 
Generally  the  experimenter  will  arrive  at 
his  own  conclusions  regarding  the  values 
to  be  used.  The  use  of  a  C  battery  in  the 
last  stage  is  generally  advisable  in  order 
to  bring  the  plate  current  value  down  to 
a  reasonable  figure.  The  biasing  of  the 
first  and  second  stages  is  not  absolutely 
necessary,  though  it  may  be  done.  The 
use  of  a  small  milliammeter  in  series  with 
each  plate  as  you  advance  across  the 
amplifier  will  readily  tell  you  the  B 
battery  current  being  used  by  each  tube. 
This  milliammeter  may  be  rigged  up  with 
clips  on  a  couple  of  wires  so  it  may  be 
clipped  into  any  of  the  plate  dircuits  of 
the  amplifier  and  you  readily  tell  what 
your  plates  are  pulling.  Too  great  a 
battery  drain  in  the  plate  circuit  is 
neither  desirable  nor  economical. 


After  looking  over  patent  papers 
granted  by  the  U.  S.  Patent  Office  during 
the  past  few  months  we  are  convinced 
more  than  ever  that  the  large  companies 
in  the  radio  combine  are  busy  getting 
protection  on  everything  that  human 
ingenuity  can  devise.  Judging  from  past 
performances  there  will  be  a  number  of 
battles-royal  to  finally  determine  the 
priority  of  certain  ones,  especially  some 
of  the  patent  applications  made  to  cover 
schemes  that  have  been  in  use  for  years 
but  not  actually  protected  by  the  inven- 
tor. In  these  cases  it  seems  the  judges 
take  the  attitude  that  if  the  original 
patentee  has  neglected  to  protect  himself 
for  any  length  of  time  in  the  past,  he  is 


no  longer  entitled  to  protection  so  the 
invention  may  be  used  by  all.  The 
patent  situation  is  one  of  the  most  com- 
plex ones  in  existence  and  the  fact  the 
radio  game  has  gone  into  the  billions 
merely  makes  the  situation  more  intri- 
cate, involving  vast  sums  of  money  to 
determine  the  worth  of  a  contested 
patent.  But  we  still  need  a  good  static 
eliminator  or  suppressor,  so  there  is  hope 
in  the  hearts  of  the  experimenters  re- 
gardless of  the  trials  and  tribulations  of 
the  inventor  in  search  for  adequate  and 
complete    protection 


Musically  inclined  fans  might  like  to 
make  a  windless,  pipeless,  pipe  organ, 
such  as  is  described  in  this  issue  by  J.  C. 
Jensen.  We  have  had  several  requests 
from  readers  for  an  audio  oscillator  and 
the  article  by  Mr.  Jensen  fills  the  bill 
completely,  we  believe. 


Work  on  short  waves  proves  more  and 
more  the  fact  that  eventually  radio 
communication  will  be  governed  by 
wavelength  for  the  various  purposes  de- 
sired. For  example  a  5  meter  set  is  hard 
to  hear  across  a  city,  or  even  a  limited 
distance,  yet  it  will  put  an  awful  signal 
into  the  ears  of  a  listener  a  thousand 
miles  away.  So  you  may  expect  to  see 
the  longer  waves  used  for  the  local  or 
short  distance  communication  and  the 
shorter  waves  to  drop  your  message  into 
the  lap  of  a  listener  at  a  distance  without 
local  interference.  The  study  of  short 
waves  is  quite  interesting. 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


47 


TfcnewAMSCO 

ALLOCATING  CONDENSER 

(STRAIGHT  LINE  FREQUENCY) 


SPREADS  the  stations  evenly 
around  the  dial  according  to 
their  frequency  in  kilo-cycles. 
Eliminates  the  crowding  on  low 
waves  and  simplifies  tuning. 

And  unlike  previous  S.  L.  F.  de- 
signs, its  "half 'a 'heart"  rotor 
plates  save  space  in  the  cabinet. 
Three  sizes — single  or  Siamese. 


ThenewAM&CO 

VERNIER   DIAL 

AS  easily  installed  as  an  ordi- 
XJL  nary  dial — and  as  easily  ma- 
nipulated. But — each  turn  of  the 
dial  is  translated  to  l/13th  the 
motion  —  giving  finesse  to  your 
fingers.  A  precision  instrument, 
without  momentum  or  back-lash. 
There  is  no  vernier  like  it  for  dis- 
tance-getting.    Low  in  price. 


ThenewAMSCO 

RHEOSTATS  AND 
POTENTIOMETERS 

NOTHING  saves  tubes  and 
batteries  like  correctly  de- 
signed, electrically  efficient  resist- 
ance instruments  in  the  radio 
circuit. 

Stromberg-Carlson,  Freed-Eise- 
mann,  Priess  Radio  and  other 
builders  of  the  highest  type  re- 
ceivers have  selected  AMSCO.  It 
will  pay  to  investigate.  Ask  your 
dealer  or  write  to  the  makers: 

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*     TtiUd  and  Approved  by  RADIO  AGE     * 


48 


RADIO  AGE /or  November,  1925 


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The  Magazine  of  the  Hour 

Reducing  Electrical 
Interference 

ID  ADIO  reception  in  some  localities  is 
-*- *-  seriously  disturbed  by  interference 
arising  from  electrical  apparatus  in  the 
vicinity.  The  only  general  remedy  for 
electrical  interference  is  cooperative  effort, 
on  the  part  of  users  of  radio  and  owners 
of  the  electrical  source's  disturbance,  to 
reduce  or  eliminate  the  causes  of  trouble, 
the  Bureau  of  Standards  points  out. 

Much  of  the  work  in  reducing  electrical 
interference  also  results  in  an  improve- 
ment in  the  operation  of  the  electrical 
devices  or  supply  lines  and  is  thus  a 
double  gain.  There  are,  however,  some 
electrical  devices  which,  even  when  in 
perfect  working  order,  cause  disturbances 
resulting  in  interference  with  radio 
reception.  But  in  many  cases  it  is 
possible  to  provide  filters,  shields,  chokes, 
etc.,  either  at  the  source  of  disturbance 
or  at  the  receiving  set,  which  do  much  to 
relieve  the  difficulties. 

A  frequent  cause  of  interference  is  the 
presence  of  alternating-current  power 
lines  near  the  antenna  or  receiving  set. 
Low-frequency  voltages  (usually  60  cycles 
are  induced  and  the  resultant  current 
flowing  in  the  receiving  circuit  causes  a 
"Humming"  sound  in  the  telephone 
receivers.  A  method  of  eliminating  or  at 
least  reducing  this  interference  is  to  place 
the  antenna  as  far  as  possible  from  the 
lines  and  at  right  angles  to  them.  When 
the  interference  can  not  be  eliminated  by 
such  means,  the  choice  of  a  receiving  set 
may  help.  An  inductively-coupled  (two- 
circuit)  receiving  set  may  help.  An 
inductively-coupled  (two-circuit)  receiv- 
ing set  is  less  susceptive  to  such  inter- 
ference than  a  single-circuit  set.  The  use 
of  one  or  more  stages  of  radio-frequency 
amplification  should  also  help  to  filter  out 
the  audio-frequency  interference.  It  has 
been  suggested  that  audio-frequency 
interference  might  be  shunted  around  a 
receiving  set  having  a  series  antenna 
condenser  by  connecting  between  the 
antenna  and  ground  terminals  of  the  set 
a  high  resistance,  which  will  offer  lower 
impedance  to  the  audio  frequency  than 
will  the  receiving  set  itself. 

Sparks  are  produced  in  the  normal 
operation  of  many  types  of  electrical 
apparatus  such  as  motors,  doorbells, 
buzzers,  gasoline  engines,  x-ray  apparatus, 
violet-ray  machines,  some  forms  of 
battery  charges,  rural  telephone  ringers, 
heating  pad  thermostats.  They  are  also 
sometimes  produced  at  defective  insula- 
tors, transformers  etc.,  of  electric  wire 
lines. 

One  remedy  for  such  types  of  inter- 
ference is  to  eliminate  the  spark.  This  is 
possible  if  the  spark  is  an  electrical  leak 
and  not  necessary  to  the  operation  of  the 
machine  in  which  it  occurs.  Many  very 
useful  electrical  machines,  however,  re- 
quire for  their  operation  the  making  and 
breaking  of  electrical  circuits  while  they 
are  carrying  current  and  whenever  this 
happens  a  spark  is  produced.  It  is  im- 
possible to  eliminate  these  machines,  so 
it  is  necessary  to  make  the  spark  of  such 
nature  or  so  arrange  the  circuits  that  the 
radio-frequency  current  is  reduced  or 
prevented  from  radiating.- 


*     TttUd  and  Approved  by  RADIO  AGE     * 


**&**        THE     •     PERFECT 


UNION 


OF 


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AND 


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De  Forest  Radio  Sets  can  be  bought 
at  prices  ranging  from  $85  to  $450. 


De  Forest  Genius  now  Humanizes  Radio! 


<nyf"ARVELOUS  new  circuit,  just 
C-/  0  L  perfected,  reproduces  flawlessly 
the  mellow,  soft  modulations  of 
the  human  voice  and  captures  the 
hitherto  elusive  overtones  of  the 
musical  register  ....  tuning  sim- 
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and  beautiful  De  Forest  W5  or  W6 
Radiophones. 

.>*->        *si        ./■> 

The  voice  of  radio  is  no  longer  flinty  and  me- 
tallic, but  mellow,  human  and  musical — 
thanks  to  the  development  by  Roy  A.  Wea- 
gant,  Vice-President  and  Chief  Engineer  of 
the  De  Forest  Radio  Company,  of  a  new  and 
marvelous  circuit. 

This  ingenious  circuit,  and  all  the  joy  it 
means  to  radio  lovers,  makes  its  first  public 
appearance  in  the  De  Forest  W5  and  W6  R  adio- 
phones,  masterpieces  of  cabinet  art  worthy 
onlyof  a  scientific  development  so  outstanding. 

So  wonderful  is  the  reproduction  of  tone  in 
the  De  Forest  W5  or  W6  that  only  the  presence 
of  the  lovely  instrument  dispels  the  illusion 
that  the  living  artist  is  in  the  rooms. 

Piano  chords  come  to  you  with  their  full 
rich  resonance — true  piano  tone.  High  notes 


dance,  ripple  and  sparkle  .  .  .  clearly,  dis- 
tinctly. . .  musically!  Those  brooding  low  notes, 
never  caught  in  average  reception,  are  heard 
distinctly — as  though  from  the  next  room. 

In  the  reproduction  of  orchestral  music  the 
full  importance  of  the  De  Forest  achievement 
stands  out.  For  the  first  time  you  get  the  over- 
tones as  well  as  the  middle  tones  .  .  .  the  ma- 
jestic roll  of  the  kettle  drums,  the  crooning 
of  the  bass  viols,  the  strident  crash  of  the 
brasses  and  the  piping  heraldry  of  the  cornets 
and  trombones.  A  symphony  orchestra  heard 
over  the  De  Forest  W5  or  W6  stirs  the  soul. 
No  incoherence,  no  oscillating  jumble  of 
noise — every  instrument,  every  octave,  in  its 
true  value.  A  magic  achievement'. 

To  the  lover  of  dance  music  the  De  Forest 
W5  or  W6  brings  more  sprightliness,  more 
beauties  of  syncopation  .  .  .  you  should  hear 
Vincent  Lopez,  Joseph  Knecht,  The  Night 
Hawks,  or  any  others  over  either  of  these  in- 
struments! 

All  the  tenderness  of  song,  every  shading  of 
the  soprano's  voice,  all  the  pathos  of  the  folk 
song — exquisite  but  elusive  elements  so  much 
desired  but  lost  in  practically  all  present-day 
reception,  are  captured  by  these  De  Forest 
masterpieces. 

To  everything  that  is  broadcast,  the  De 
Forest  Radiophone  gives  animation,  life  and 
humanness. 


But  Tonal  Supremacy  is  Not  All — 

Elbert  McGran  Jackson,  renowned  sculptor, 
architect  and  painter,  put  into  this  hand- 
wrought,  hand-carved  cabinet  the  spirit  of 
radio,  in  design,  in  motif — it  is  not  an  adap- 
tation of  a  phonograph.  An  image  of  charm- 
ing individuality,  it  harmonizes  with  the  set- 
ting of  any  home. 

One  unit,  everything  self-contained — not  a 
wire  in  sight,  nothing  to  connect  .  .  .  and 
portable;  move  it  any  place!  Only  charm  and 
beauty  for  the  eye. 

The  artistic  conical  reproducer  is  an  insepa- 
rable part  of  the  cabinet  and  its  tonal  mecha- 
nism peerlessly  attuned  to  that  of  the  V/earant 
circuit.  There  are  just  two  controls  for  tuning, 
and  these  operate  on  one  dial,  which  makes 
the  normally  perplexing  task  of  "tuning  in'" 
extremely  simple.  There  are  special  power 
tubes  in  the  fifth  and  sixth  sockets  which  can 
give  you  volume  to  flood  an  auditorium,  if 
you  desire  it.  And,  at  your  fingers'  tips,  the 
means  to  tune  in  a  far-distant  station  you 
want  no  matter  how  powerful  nearby  stations 
may  be. 

See  the  incomparable  De  Forest  W5  and  W6 
at  your  De  Forest  dealer's  or  write  for  an  in- 
teresting booklet  describing  these  master- 
pieces in  detail. 


DE  FOREST  RADIO  CO.,  Jersey  City,  N.  J. 


*  De  forest 


<3he  Qreateft 
J\famt  inRadio 


DEALERS       IN      ALL       CITIES       AND       RADIO        COMMUNITIES  iV^. 

fHE    EPOCH-MAKING  ACHIEVEMENT  WHICH  MAKES  ORDINARY    RADIO     RECEPTION   A   THING  OP  YESTERDAY^ 


*    Tested  and  Approved  by  RADIO   AGE    * 


50 


RADIO  AGE  for  November,  1925 


'or- 


Real  Enjoyment 


No.  205 


LOUD  SPEAKER 

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Some  Facts  on  the  Magnetic 
Theory 

(  Continued  from  page  21) 
upon  each  other,  and  efforts  have  been 
made  to  so  place  the  coils  in  the  modern 
receiving  set  that  the  effect  is  reduced 
to  a  minimum.  Various  tests  have 
proven  that  in  two  adjacent  magnetic 
fields,  the  field  of  each  is  distorted,  either 
pushed  apart  or  drawn  more  closely 
together  by  the  action  of  the  other, 
depending  on  the  polarity.  An  alternat- 
ing current  or  varying  current  creates  a 
vibration  in   the   field. 

In  radio  transmission  the  high  fre- 
quency vibrations  carried  out  by  the 
transmitting  aerial,  located  anywhere 
within  the  great  magnetic  field  of  the 
earth,  tend  to  distort  the  field  as  in  two 
small  adjacent  coils.  This  disturbance 
or  vibration  is  carried  out  in  all  direc- 
tions similar  to  the  waves  sent  out  from 
a  disturbance  on  the  quiet  surface  of  a 
pond,  or  more  nearly  like  sound  waves 
radiating  in  all  directions,  even  upward 
and  downward  through  the  magnetic 
lines  of  force.  These  vibrations  cause  a 
change  in  intensity  of  the  earth's  mag- 
netic field  in  somewhat  the  same  manner 
that  sound  waves  cause  a  change  in 
intensity  of  the  air,  each  crest  or  wave 
being  followed  by  a  low  or  thin  area. 

The  magnetic  field,  like  any  other  body, 
tends  to  remain  at  rest  or  in  balance.  As 
the  wave  progresses  across  any  conductor, 
a  small  current  is  generated  which  tends 
to  balance  or  overcome  the  effect  of  the 
waves,  consequently  the  current  generat- 
ed is  an  exact  duplicate  of  the  originat- 
ing current  which  started  the  disturbance. 
The  aerial  being  a  conductor  is  therefore 
charged  with  a  current  which  tends  to 
keep  in  balance  the  magnetic  field  sur- 
rounding it.  This  is  the  current  detected 
by  the  receiving  set  and  transformed 
into  audible  signals. 

To  Generate  Electricity 

IN  generating  electricity,  engineers 
have  learned  that  the  coils  in  the 
generator  must  cut  across  or  through  the 
magnetic  field  of  the  generator  in  order 
to  generate  a  current  in  the  service  lines. 
Radio  experience  has  taught  us  that 
better  results  are  obtained  in  reception 
if  the  aerial  is  strung  pointing  toward  or 
away  from  the  sending  station  sought. 
This  is  decidedly  true  of  the  loop  aerial 
which  must  be  in  such  a  position  that 
the  oncoming  wave  or  magnetic  disturb- 
ance cuts  directly  into  the  plane  of  the 
aerial.  If  the  loop  were  placed  broadside 
to  the  oncoming  wave,  the  change  in 
intensity  of  the  magnetic  field  surround- 
ing the  loop  would  be  the  same  at  all 
points  around  the  loop;  in  other  words, 
the  magnetic  field  in  the  plane  of  the 
loop  would  at  no  time  be  out  of  balance; 
therefore  no  current  would  be  generated. 
A  study  of  the  earth's  magnetic  field 
discloses  the  fact  that  it  is  a  constantly 
changing  field  due  to  outside  influences, 
the  principle  one  of  which  seems  to  be 
the  sun.  During  the  daylight  hours  we 
have  the  greatest  changes.  During  any 
one  hour  between  8:00  a.  m.,  and  5:00 
p.  m.,  there  is  a  greater  change  in  inten- 
sity and  direction  of  the  earth's  magnetic 
field  than  during  the  whole  of  the  night 
from  9:00  p.  m.,  to  4:00  a.  m.  Every 
day  there  is  a  magnetic  tide,  or  magnetic 
"wind"  blowing,  if  it  may  be  called  such, 
which  upon  the  setting  of  the  sun  calms 
down  and  almost  ceases  during  the  hours 
of  darkness,  only  to  rise  again  at  dawn. 
We  know  by  observation  that  sound  is 
I  transmitted  much  easier  and  clearer  on  a 

{Turn  to  page  62) 
*    Tested  and  Approved  by  RADIO  AGE    * 


The  Magazine  of  the  Hour 


A  Six  Tube 
IN  CONSOLE 

$125  LIST  \*g 

(With  Loud  Speaker)      W  ^^ 

DIANA     "SIX" 

A  perfect  set  in  a  beautiful  cab- 
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Radio  Receiving  Set 

At  Authorized  Dealers 


Read  the  Classified  ads  on  page 
79   for   some    real    BARGAINS! 


RADIO  AGE  for  November,  1925 


"Socket   of  Future"    Claimed 
by  Pacent 

One  of  the  interesting  improvements 
in  the  development  of  radio  reception  is 
embodied  in  the  new  universal  base  that 
has  been  adopted  for  Radiotron  vacuum 
tubes.  It  permits  interchangeability, 
lowers  the  total  capacity  of  any  circuit, 
and  increases  the  efficiency  of  the  elec- 
trical contacting  arrangement  with  the 
tube  prongs. 

The  tube  socket  of  the  future  will  be 
a  small  bridge  shaped  article  supporting 
a  disc  with  four  holes,  similar  to  that 
which  has  been  designed  by  the  Pacent 
engineers.  The  contacts  will  be  com- 
pletely out  of  sight,  but  so  arranged  that 
they  grip  the  sides  of  the  tube  prongs 
with  firm  side  contact. 

The  new  socket  designed  by  the  Pacent 
engineers  is  constructed  of  Isolantite. 
This  material  has  been  found  practically 
ideal  at  radio  frequencies  with  negligible 
dielectric  loss,  which,  coupled  with  the 
small  amount  of  metal  required  in  the 
contacting  devices  of  the  socket,  reduces 
the  capacity  effect  between  grid  and  plate 
thus  making  the  radio  frequency  cir- 
cuits far  more  stable  in  operation  than 
has  been  the  case  with  the  older  type  of 
tubes. 

Probably  the  most  important  advan- 
tage of  the  new  type  tube  base  is  that  it 
permits  the  design  of  a  socket  with  a  one 
piece  contact  in  such  manner  that  when 
the  connecting  wire  is  soldered,  a  contin- 
uous circuit  connection  throughout  is 
established.  This  alone  is  a  great  ad- 
vance in  efficiency. 


The  Magazine  of  the  Hour  51 


The  Humble  Rheostat  is 
Worthy  of  Praise 

Little  and  much  can  be  said  about  the 
humble  rheostat  that  hides  behind  the 
front  panel  of  our  receiving  sets.  Seldom 
seen,  and  soon  forgotten,  this  important 
piece  of  apparatus  opposes  the  flow  of 
electricity  to  the  filaments  of  the  vacuum 
tubes  while  the  set  is  in  operation. 

Without  a  rheostat  the  filaments 
would  soon  become  damaged  beyond 
repair,  due  to  too  much  current  passing 
through  and  causing  the  thorium  coating 
to  disintegrate  and  flake  off.  This  is  an 
every  day  occurrence  where  the  rheo- 
stats are  turned  on  too  far  and  is  the 
principal  reason  for  so  many  tubes  going 
"dead." 

In  the  struggle  to  oppose  the  flow  of 
current,  the  wire  becomes  warm,  even 
hot  if  the  tube  requires  considerable 
"juice."  As  the  temperature  of  the 
rheostat  rises  it  causes  the  wire  to  expand. 
If  the  wire  becomes  hot  enough  to  char 
the  insulation  on  which  it  is  wound,  it 
becomes  loose,  the  wires  touch  each 
other,  and  the  rheostat  loses  its  smooth 
operation  and  trouble  begins. 

It  is  for  these  reasons  that  the  new 
Frost  rheostat  has  extra  heavy  wire  on 
a  strip  -of  insulating  material,  the  whole 
being  in  a  moulded  bakelite  frame.  Heat 
will  not  ruin  the  rheostat  by  changing 
the  shape  of  the  insulating  strip  of  the 
frame,  and  one  can  be  assured  of  faithful 
service  from  this  part  of  a  radio  set. 


WHO  GETS  IT? 
The  Radio  Age  Receiver — the 
most  talked-of  set  of  the  year, 
will  be  given  away  at  the  Chicago 
Radio  Show  in  November.  Who 
will  get  it?  You  have  a  chancel 
See  page  20! 


ypemne~-ri 

in  finish  an 


dpa 


wormanco 


WHETHER  you  build  your  own  radio  re- 
ceiver or  buy  a  factory-built  set,  you  will 
improve  your  9et  by  installing  Allen-Bradley  Perfect 
Radio  Devices.  Not  only  are  Allen-Bradley  Radio 
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fails  to  amaze  and  delight  you.  The  eight  salient, 
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Perfect 


Bradleystat 

Filament  Control 
for  all  Tubei 


Bradloylea  k — Perfect 

Grid  Leak  M  to  10 

Megohms 


t  Terminals  are  readily 
accessible.  Designed 
for  bus  bar  wire  or 
terminal  lugs. 

O  Metal  parts  are  heav- 
ily  nickeled  and 
buffed  to  a  high  polish. 

T  Container  is  made  of 

~*  glazed  porcelain  that 

excludes  moisture. 

A  Specially  -  treated 
graphite  disc9  give 
amazingly  wide  and 
noiseless  control. 


5  Internal  switcn  opens 
battery  circuit,  if  de- 
sired, by  turning  knob 
to  the  left. 
/C  Highly  polished  bake- 
lite  knob  is  removable 
if  you  prefer  to  match 
other  dials. 

7  One-hole  mounting 
makes  installation 
simple  and  easy  on  all 
sets. 
Q  Can  be  used  with  any 
panel  thickness.  Back 
panel  extension  is  ex- 
tremely small. 


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*     Tested  and  Avvroved  bu  RADIO  AGE     * 


52 


RADIO  AGE  for  November,  1925 


* 


The  new  five  ampere  Tungar— at  the 
same  price  as  the  old — means  a  quick 
charge  of  all  kinds  of  storage  batteries. 

— It  is  more  silent  than  ever. 
— It  cannot  burn  out  Radiotrons. 
— It  cannot  create  radio  interference. 
— It  is  ideal  for  auto  batteries — and 
charges  2  to  6  volt  radio  "A"  bat- 
teries, or  24  to  96  volt  "B"  batteries, 
in  series  —  all  without  attachments. 


The  Tungar  is  a  G-E 
product  developed  in'the 
great  Research  Labora- 
tories of  GeneralElectric. 

Two  ampere  Tungar 
(East    of  the    Rockies). 

$18.00 

Five  ampere  Tungar 
(East    of   the     Rockies). 

$28.00 
60  cycles— 110  volts 


iBATTERYCHARGEff 


TUNG-AR—a  registered  tradem  ark— is  found  only 
on  the  genuine.     Look  for  it  on  the  name  plate. 

Merchandise  Division 
General  Electric   Company,   Bridgeport,    Conn. 


GENERAL  ELECTRIC 


Radio's  biggest  season  is  here.     Get  our 

new  catalog  showing  huge  stocks  of  radio 

parts,  sets,  kits  at  lowest  rock-bottom 

prices.   Quick  service.    Wonderful  spe-    S*ZAfif0/ 

c'al  offer  on  best  sets,  tubes,  batter-     . 

ies.     Write  for  free  copy.  ^ 

W.-C  Brauo  Co.,  34-50  S.  Clinton  St,  Chicago,  U.  S.  A.~ 


Big  Money  in  Radio 

Demand  for  high  pay  radio  men  is  so  great  that  a 
big  Kansas  City  wholesale  concern  is  now  fitting 
men  free  to  get  Into  the  radio  business  for  them- 
selves and  make  $b0  to  $200  a  week  without  any 
capital  invested.  Select  territory  open.  Send  to- 
day for  free  catalog  and  amazing  offer.  Write  direct 
to  Mr.  H.  j.  Saizow,  Standard  Radio  Co.,  1424 
Walnut  St.,  Kansas  City.  Mo. 


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X-L  PUSH  POSTS 

A  binding  post  that  really  does  excel, 
looks,  action,  service,  and  convenience. 
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loose  from  vibration.  No  screwing  or 
danger  of  shearing  off  wires. 
Furnished  attractively  plated  with 
soldering  lug  and  necessary  markings. 

Price    Each 15    Cent; 

X-L    RADIO     LABORATORIES. 
2424    Lincoln    Avenue    N  Chicago 


* 


TO  THE  MAN  WITH  AN  IDEA 

I  offer  a  comprehensive  service.  If  you 
have  a  new  invention,  I  will  assist  you  in 
obtaining  a  patent.  Write  for  further  in- 
formation: RICHARD  N.OWEN,  PAT- 
ENT ATTORNEY,  OWEN  BUILD- 
ING, WASHINGTON,  D.  C. 

Tested  and  Approved  by  RADIO  AGE     * 


The  Magazine  of  the  Hour 

Secretary   Hoover    Faces  His 
Big  Task 

(Continued  from  page  32) 
a  legitimate  and  a  valuable  purpose  to 
the  listener  before  we  allow  him  to  further 
congest  the  overcrowded  lanes. 

But  above  all  we  must  not  crystallize 
things  into  law  which  will  impede  the 
development  of  the  art.  Any  day  may 
see  discoveries  which  may  simplify  the 
whole  of  our  problems  of  congestion.  And 
in  any  event  the  undoubted  improvement 
in  our  sending  and  receiving  sets  every 
year  contributes  to  widen  the  paths 
through  the  air.  We  have  great  unsolved 
problems  in  the  amount  of  power  neces- 
sary to  give  real  service  to  listeners  even 
against  opposition  of  static  and  summer 
conditions  and  without  adding  still  further 
congestion  and  interference. 

We  have  all  watched  this  industry 
grow  from  the  curiosity  of  a  scientific  toy 
to  a  communication  system  now  Well 
nigh  universal.  It  is  better  and  greater 
than  it  was  a  year  ago. 

So  great  has  it  become  in  service  that  I 
believe  it  would  be  almost  possible  in  a 
great  emergency  for  the  President  of  the 
United  States  to  address  an  audience  of 
forty  or  fifty  millions  of  our  people.  It  is 
bringing  a  vast  amount  of  educational  and 
informative  material  into  the  household; 
it  is  bringing  about  a  better  understanding 
amongst  all  of  our  people  of  the  many 
problems  which  confront  us;  it  is  improv- 
ing the  public  taste  for  music  and  enter- 
tainment; it  is  bringing  contentment  into 
the  home.  We  are  at  the  threshhold  of 
international  exchange  of  ideas  by  direct 
speech,  and  it  will  bring  us  better  under- 
standing of  mutual  world  problems. 

Only  over-optimistic  prophets  would 
attempt  to  predict  radio  advance.  One 
thing  we  are  sure  of — that  the  radio 
industry  is  only  in  its  youth,  that  it  will 
continue  to  grow  with  increasing  strength. 
If  it  will  succeed  it  must  continue  as  in  the 
past  to  devote  itself  to  actual  public  ser- 
vice to  which  it  is  already  dedicated. 


Getting  the  Farmer  to  Buy 
a  Radio 

(Continued  from  page  28) 
25    per    cent    being    willing     to     buy. 

How  owners  make  use  of  sets — 83.97 
per  cent  reported  they  make  use  of 
radio  weather  reports;  80.98  per  cent 
use  the  market  reports;  70.92  per  cent 
said  they  did  not  object  to  advertising 
over  the  air,  94.96  per  cent  declared 
they  were  satisfied  with  local  programs. 

What  kind  of  programs  does  the  farm 
family  like? — Market  reports  was  voted 
for  by  143  farmers  out  of  427  as  the 
most  popular  program  for  the  man  of 
the  house,  and  114  voted  for  the  crop 
service.  Jazz  orchestras  came  third, 
popular  songs  fourth,  informative  talks 
fifth  and  religious  services  sixth.  Classical 
and  operatic  music  are  not  in  the  run- 
ning, so  far  as  the  man  of  the  farm  is 
concerned.  Popular  songs  were  voted 
first  by  the  majority  of  farm  women, 
with  religious  music  second,  informative 
talks  third,  religious  services  fourth, 
jazz  orchestras  fifth  and  classical  music 
sixth.     (Copyright  by  McGraw-Hill  Co.) 


RADIO  AGE  for  November,  1925 


Spanning  the  U.  S.  with 
Low  Power 

(  Continued  from  page  24) 
the  transmitter.  Rheostat  R-2  has  10 
ohms  resistance,  for  the  two  "A"  tubes 
employed  in  the  receiver.  Both  tubes 
are  supplied  with  voltage  from  the  45 
volt  tap  on  the  "B"  battery. 

Such  an  outfit  might  well  be  laid  out 
on  a  fairly  large  table,  with  plenty  of 
separation  between  transmitter  and  re- 
ceiver but  with  short  leads  to  antenna 
and  counterpoise.  The  batteries  could 
be  placed  on  the  floor  underneath  the 
set.  The  "B"  battery  used  for  the  send- 
ing outfit  ought  not  to  exceed  five  "heavy 
duties"  and  can  well  get  along  with 
three  of  them. 

The  constructional  data  is  given  in 
rather  sketchy  manner,  but  is  sufficient 
for  the  man  who  has  had  some  experience 
with  amateur  apparatus  and  who  knows, 
for  instance,  which  side  to  connect  the 
rotor  plates  of  the  variables,  that  the 
tickler  and  primary  go  at  the  filament 
end  of  the  receiver  secondary  coil,  etc. 

Other  transmitting  circuits  may  be 
used,  of  course.  In  getting  results,  most 
of  the  work  must  be  done  in  daytime, 
as  it  is  then  that  fewest  stations  are  on 
the  air.  Patience  is  also  necessary,  but 
once  the  "ham"  gets  into  communica- 
tion with  a  few  stations,  more  follow 
rapidly.  It  is  best  to  answer  "CQ" 
calls  that  are  given  on  about  the  same 
wave  as  the  transmitter,  as  it  is  in  that 
wavelength  vicinity  that  the  distant 
fellow  is  going  to  listen  first  for  a  reply. 


The  Magazine  of  the  Hour 


53 


Clearing  Up  the  Ether 
Started  at  Last 

(Continued  from  page  22) 
the  St.  Paul  Gas  Light  Company,  the 
Northern  States  Power  Company,  the 
Twin  City  Rapid  Transit  Company,  the 
Northwestern  Bell  Telephone  Company, 
the  Tri-State  Telephone  Company,  the 
Twin  City  Radio  Club  of  Amateurs, 
the  Chief  Engineer  of  the  Gold  Medal 
Radio  Station  and  the  President  and 
Secretary  of  the  Northwest  Trade  Asso- 
ciation. This  committee  has  held  six 
meetings.  The  speaker  has  acted  as 
Chairman.  So  far,  our  effort  has  been 
concentrated  on  securing  a  classification 
of  the  various  types  of  interference. 
This  has  been  quite  a  task.  In  addition, 
the  Northwest  Radio  Trade  Association 
has  circulated  blanks  among  its  members 
which  may  be  used  by  broadcast  listeners 
for  reporting  cases  of  interference.  These 
blanks  have  been  drawn  up  in  such  a 
way  as  to  discourage  indefinite,  vague 
complaints,  but  to  adequately  take  care 
of  intelligent  ones. 

"Having  taken  steps  to  classify  induc- 
tive interference,  and  to  determine  just 
what  types  of  interference  exist,  the 
Twin  City  Inteference  Committee  is  now- 
confronted  with  the  task  of  finding  means 
whereby  interference  can  be  minimized. 
Complete  information  giving  location  of 
specific  cause  of  interference,  caused  by 
defective  equipment,  will  of  course  be 
acted  upon  immediately  by  those  owning 
and  operating  such  equipment.  How- 
(Turn  to  page  55) 


The  Bridge  to  Amplication  Without  Distortion  *f£ 

Daven  engineers  were  pioneers.     They  blazed  the  way  for  others  to  follow.     They 
designed  and  built  the  first  Resistance  Coupled  Amplifier  offered  the  public.    They 
found  resistance  coupling  in  an  experimental  stage.     They  perfected  it. 
Daven  Resistance  Units,  Amplifier  Kits  and  Super-Amplifiers  are  accepted   by  the  foremost    authorities 
in  Radio  as  standard.      The  Daven  Super-Amplifier,  for  use  in  any  known  set  or  circuit,  is  priced  at  $15.00. 


RESISTOR  MANUAL 

Manufacturers  of  high 
grade  sets  are  turning  to 
Resistance  Coupled  Ampli- 
fication. The  authority  is 
The  Resistor  Manual.  At 
your  dealer's,  25c;  or  by 
mail,  30c. 


A  NEW  TUBE  BY  DAVEN 

To  meet  the  exacting  requirements  of  Resis- 
tance Coupled  Amplification  the  Daven  Radio 
Corporation  has  created  a  new  product,  the 
DAVEN  HIGH  MU  VACUUM  TUBE, 
Type  MU  20.  It  is  designed  for  one  specific 
purpose  only — to  increase  the  amplification 
of  the  Daven  Resistance  Coupled  Amplifier 
so  as  to  exceed  that  of  ordinary  audio  fre- 
quency coupling.  The  Daven  High.  Mil  is 
a  6  volt,  1-4  ampere  tube  with  an  amplifica- 
tion constant  of  20.  The  price  is  $4.00.  Daven 
Power  Tube  Type  Mu  6  is  recommended  for 
last  or  output  stage.     Price  $5.00. 

Daven  products  are  sold  only 
by  good  dealers 

~&&  Sine  o/-MtX* 
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For  Dealers:  Send  your  letter- 
head or  card,  or  this  coupon  a  rid 
we  will  have  our  nearest  distrib- 
utor communicate  with  you.. 


THE    BIG     LITTLE    THINGS    OF    RADIO 


RADIO  AGE  SUBSCRIPTION  BLANK 


$2.50  A  YEAR 


Radio  Age,  Inc. 

500  North  Dearborn  Street, 
Chicago 

Gentlemen:  Please  enter  my  subscription  for  RADIO  AGE,  the  Magazine  of  the  Hour,  for  one 
year,  beginning  with  your  next  issue,  for  which  I  enclose  $2.50. 


Narne- 


Street  Address-. 
City 


State- 


Send  cash,  money  order  or  draft. 


*     Tested  and  Approved  by  RADIO  AGE     * 


54 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


t 


Developed  for  Those  j 
WhoDemand  theBest 

APEX 
VERNIER  DIALS 

are  constructed  on  exhaustively  tested 
and  truly  scientific  principles  and  are 
engineered  to  meet  the  precise  re- 
quirements of  experts — consequently 
they  more  than  meet  the  expectations 
of  the  average  radio  user.  They  bring 
in  distant  stations  with  alacrity  and 
positiveness  seldom  encountered  and 
provide  control  and  accuracy  essen- 
tial to  full  radio  enjoyment.  They 
impart  a  degree  of  elegance  that  cre- 
ates a  marked  improvement  in  the 
appearance  of  any  set.  Clockwise  and 
counter  clockwise. 

Royal  Brass  Finish.  4  in.  $2.00;  3Vi  in.  $1.65 
Satin  Silver  Finish.  4  in.  2.50;  3<A  in.  1.90 
DeLuse  Gold  (24K)  4  in.    3.50;  3Vi  in.    2.50 

APEX 
RHEOSTAT  DIALS 

are  little  brothers  to  Apex  Vernier 
Dials.  Accurate, handsome — a  neces- 
sity to  satisfactory  operation  and 
beauty  of  appearance. 

Royal  Brass  Finish $  .75 

Satin  Silver  Finish 85 

DeLuxe  Gold  (24K) 1.00 


Quality Radio Apparatus 


If  your  dealer  is  unable  to  supply  you.  order 
direct  from  us. 

Apex  Electric  Mfg.  Co. 

1410  W.  59th  St.,  Dept.  1111,  CHICAGO 


Free,  big  Radio  Catalog 
and  Guide  brimful  of  new-  i 
estideas  over  lOOspeclalhook- 
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parts.  Besure  to  get  this  thrifty 
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Standard  Radio  Receivers 

Some  time  ago  RADIO  AGE  inaugurated  a  new  department  called  "Know 
Before  You  Buy,"  to  serve  as  a  guide  to  the  prospective  radio  purchaser  in 
deciding  on  the  receiver  best  suited  to  his  individual  needs.  Fans  'hroughout 
the  country  have  shown  a  keen  interest  in  this  new  feature,  and  accordingly  it 
is  being  made  a  feature  of  all  numbers  of  RADIO  ACE.  Readers  are  invited 
to  write  us  concerning  the  sets  in  which  they  are  interested,  and  manufacturers 
also  are  asked  to  send  us  material  describing  their  sets. 

The  "Why"  of  The  Audiola  Receiver 


Proper  Balance  of 
Parts  a  Feature 


TO  GIVE  the  best  results,  a  radio  set 
must  be  built  of  parts  designed 
especially  for  use  with  each  other,  so  that 
there  will  be  a  balance  between  them. 
This  relationship  between  coils  and  con- 
densers is  especially  important.  Audiola 
manufactures  their  own  low-loss,  dust- 
proof  condensers  and  low-loss  coils,  so 
that  there  will  be  a  perfect  balance  be- 
tween the  two. 

They  also  manufacture  low-loss  sock- 
ets which  are  used  in  all  Audiola  Radio 
Receiving  Sets. 

An  efficient  circuit,  such  as  is  used  in 
the  Audiola  "Big  Six"  and  the  Audiola 
"Sealed  Five,"  high  grade  balanced  parts, 
skilled,  conscientious  workmanship,  and 
careful  inspection  inevitably  results  in 
high  grade  radio  receiving  sets. 

Specifications 

"Big  Six" 

Six  tube  tuned  radio  frequency  set  with 
power    amplification. 

Panel — seven  by  twenty-one  inches, 
Walnut    finish. 

Sub  Panel — Walnut  finish  covering 
practically  entire  interior  of  set. 

Cabinet — genuine  Walnut,  beautifully 
finished. 

Rheostats — (3)  one  each  for  radio  fre- 
quency tubes,  detector  tube  and  audio 
tubes. 

Transformers — three  of  Thordarson 
make  or  equal,  one  stage  of  audio  plus 
power   amplification. 


Coils — spider  web,  low-loss,  of  Audiola 
manufacture. 

Condensers— dust-proof,  low-loss,  of 
Audiola   manufacture. 

Sockets — low-loss,  of  Audiola  manu- 
facture. 

Wiring — first  made  mechanically  self- 
sustaining  and  then  soldered. 

Circuit — standard  tuned  radio  fre- 
quency type,  with  addition  of  power 
amplification. 

"Sealed  Five" 

Five  tube  tuned  radio  frequency  set. 

Panel — eighteen  by  seven  inches,  Wal- 
nut   finish. 

Sub- Panel — Walnut  finish  covering 
practically  entire  interior  of  set. 

Cabinet — beautiful   Walnut   finish. 

Rheostats — (2)  one  for  detector  tube, 
and  one  for  radio  and  audio  tubes. 

Transformers — two  of  three-to-one 
ratio  of  All  American  make  or  equal. 

Coils — spider  web,  low-loss,  of  our  own 
manufacture. 

Condensers — dust-proof,  low-loss,  of 
our  own  manufacture. 

Sockets — low-loss,  of  our  own  manu- 
facture. 

Wiring — first  made  mechanically  self- 
sustaining  and  then  soldered. 

Circuit — standard     tuned     radio  _  fre- 
quency   type,    revamped    to    eliminate 
oscillation    or   howls   and   to   give   more 
"pep"  than  the  usual  five  tube  set. 
(Turn  to  page  56) 


BECOME  ARADIOIXPERI 

t*  3  MONTHS 

Stvuy 

vttHoxe 


Our  uuxukl  I 


if    rvu    m»ks    food. 
*W%  ma  todi-     - 


a  r»dlo  enjlnear.-  ThouMOdj  o 
Her*  U  the  Held  that  will  nak 
book.    "Miilloni    Untouched." 


Insure  Distortionless  Amplifica- 
tion and  a  clarity  of  tone  not  obtain- 
»•-        ed  through  any  other  resistances.     All 
-  capacities  12,000  Ohms  and  up.  List  price  $1.50. 
Special  sizes  to  order.  Write  for  full  information. 
Crescent  Radio  Supply  Co.,     5  Liberty  St,     Jamaica,  L,  I. 


*     Tested  and  Approved  by  RADIO  AG^     # 


RADIO  AGE  for  November,  1925 


What  the  Broadcasters  are  Doing 


55 


(Continued  from  page  53) 
ever,  the  task  of  locating  the  exact  source 
is  often  a  long  and  tedious  one.  The 
public  utilities  of  the  Twin  Cities  have 
already  individually  devoted  much  time 
and  money  to  this  problem  in  spite  of 
the  fact  that  many  times  after  extensive 
search,  they  find  that  the  interfering  de- 
vice is  neither  owned  nor  controlled  by 
them.  The  Northwest  Radio  Trade 
Association  contemplates  the  establish- 
ment of  trouble  shooting  service  to  assist 
in  the  work  already  so  ably  initiated  by 
the  public  utilities.  It  is  only  by  such 
whole-hearted  co-operation  as  I  have 
outlined  that  we  can  arrive  at  the  ulti- 
mate solution  of  our  problems  in  induc- 
tive radio  interference. 

"Neglecting  radio  interference,  there 
are  three  factors  which  determine  whether 
or  not  reception  from  a  given  radio  broad- 
casting station  can  be  made  satisfactory 
at  a  given  location.  These  factors  are: 
The  intensity  of  the  received  signal,  the 
intensity  of  static,  or  atmospherics,  and 
the  intensity  of  inductive  interference. 
In  discussing  these  factors,  the  terms 
'signal  level,'  'static  level'  and  'inter- 
ference level'  may  be  applied  to  the 
average  conditions  existing  at  a  given 
location  during  a  given  period  of  time. 
With  modern  efficient  amplifying  receiv- 
ing equipment,  it  is  not  the  actual  levels 
of  these  three  factors  which  are  impor- 
tant, but  their  relative  values.  A  signal 
from  a  broadcasting  station  can  easily 
be  amplified  to  satisfactory  intensity, 
providing  the  ratio  of  the  signal  level  to 
the  static  and  interference  levels  is 
sufficiently  high.  If  this  ratio  is  not 
sufficiently  high,  satisfactory  reception 
cannot  be  obtained. 

"During  the  summer  months,  the  stat- 
ic level  is  usually  much  higher  than  the 
inductive  interference  level,  and  conse- 
quently it  is  static  which  limits  the  recep- 
tion of  distant  stations.  Man  has  not 
yet  found  a  satisfactory  method  of  con- 
trolling the  static  level.  During  the  win- 
ter months,  the  static  level  drops  almost 
to  zero  and  consequently  it  is  the  inter- 
ference level  which  limits  reception.  It 
is  therefore  but  natural  that  we  should 
hear  more  about  inductive  interference 
in  the  winter  than  in  the  summer  time. 

"The  time  is  not  far  distant  when  we 
must  determine  just  how  much  right  to 
protection  from  inductive  interference  the 
user  of  an  ultra  sensitive  receiving  set  is 
entitled  to.  If,  in  any  community,  we 
succeed  in  lowering  the  interference  level 
to  a  given  point  the  users  of  sensitive 
receivers  immediately  increase  the  amount 
of  amplification  in  use  until  the  same  in- 
terference level  exists  in  his  mind,  as 
before,  and  the  same  problem  arises 
again. 

"My  experience  in  the  radio  communi- 
cation field  has  led  me  to  the  conclusion 
that  there  is  no  other  field,  where  the  need 
of  co-operative  effort  directed  towards 
the  solution  of  common  problems  is 
greater.  It  is  only  by  bearing  con- 
stantly in,  mind  the  necessity  for  co-opera- 
tion with  our  fellow  men,  that  we  can 
arrive  at  satisfactory  solutions  of  all  of 
the  problems  which  today  confront  the 
radio  industry  and  those  associated 
with  it." 


"Where  is  the  difference 
in  radio  transformers  ? 


THE  audio  frequency  trans- 
formers in  your  radio  perform 
a  most  important  duty.  They  aid 
in  increasing  the  volume  of  sound 
...  in  building  it  up  to  the  desired 
strength.  BUT — 

When  sound  is  increased,  the 
tendency  is  toward  distortion. 
That'swhere  the  difference  comes 
in  transformers.  Inefficient  trans- 
formers will  give  distorted  recep- 
tion, just  as  a  defective  mirror  will 
show  a  distorted  image. 

Whether  you  are  building  a  set, 
or  buying  one,  be  sure  about  the 
transformers.  No  radio,  remem- 
ber, can  be  better  than  its  trans- 
formers. A  safe  guide  to  follow  is 
the  Jefferson  trade  mark.  You  can 
depend  on  quality  in  perform- 
ance when  the  name  "Jefferson" 
is  on  the  product. 

Jefferson  Transformers  are  made  by 
transformer  specialists — the  world's 
largest  manufacturers  of  small  trans- 
formers. There  is  a  very  definite  reason 
why  leading  radio  engineers  specify 
"Jefferson."  You'll  find  it  in  the  clear, 
sweet,  life-like  amplification  which 
Jefferson  Transformers  give.  Sold  by 
the  better  dealers,  used  by  leading  set 
manufacturers. 

JEFFERSON  ELECTRIC 
MANUFACTURING  CO. 

501  So.  Green  St.,      Chicago,  111. 

Makers  of  Jefferson  Radio,  Bell  Ringing  and 
Toy  Transformers;  Jefferson  Spark  Coils  for 
Automobile,  Stationary  and  Marine  Engines; 
Jefferson  Oil  Burner  Ignition  Transformers. 


* 


JEFFERSON 

Tube  Rejuvenator 

Keep  your  radio  tubes  like 
new!  Rejuvenate  them  regu- 
larly, AT  HOME,  just asyou 
recharge  your  storage  bat- 
tery. Jefferson  Home  Rejuve- 
nator doubles  and  trebles 
tube  life,  quickly  pays  for  it- 
self. Raises  your  set'sefficien- 
cy  to  100%,  and  keeps  it  there! 
Completely  restores  para- 
lyzed or  exhausted  tubes. 
Takes  large  or  small  tubes — 
rypes  20I-A,  301-A,  UV-199, 
C-299,  5-VA.  Don't  be  with- 
out this  long-awaited  radio 
necessity.  $7.50  at  leading 
dealers. 


JEFFERSON 

RADIO  TRANSFORMERS 


*      Tested  and  Arrornved  bv  RADIO  AGE     ¥ 


56 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


The  New  Model  L-3  Ultradyne 

By  The  Experimenter 

( Continued  from  page  54) 


GUARANTEED  FOR  A 
LIFETIME 

The  Aalco — the  lowest  resistance  loop  made — 
assures  maximum  selectivity  and  range,  and 
perfect  dial  matching  made  possible  by  variable 
inductance.  Constructed  of  the  highest  grade 
materials  in  a  new  and  masterly  design..  Length. 
24  in  — Normal  Ht.  30  in. — Wavelength  ranee 
120-600  meters.  LABORATORY  TEST  RE- 
SULTS   UPON    REQUEST. 


Price  $15.00 


AALCO  RADIO  LABS. 
6350  Cottage  Grove  Avenue,  CHICAGO 


I  HAVE  had  before  me  a  cabinet  of 
pleasing  appearance.  It  looks  well 
from  all  sides  but  it  is  the  front  that  holds 
the  eye.  Besides  being  a  thing  of  beauty, 
it  is  different.  It  might  or  might  not  be 
taken  for  a  radio  set;  at  least  it  does  not 
resemble  the  sets  one  is  used  to  seeing. 
I  took  it  for  a  cabinet  type  loud  speaker 
until  I  was  told  that  it  was  a  full  fledged 
radio  set  with  a  built-in  loud  speaker  and 
everything. 

This  was  the  new  Model  L-3  Ultradyne 
and  R.  E.  Lacault  is  the  man  who  de- 
veloped it.  I  thought  back  to  the  time 
he  first  introduced  the  original  Ultradyne 
Receiver  to  the  radio  public,  who  ac- 
cepted it  with  confidence  and  who  now 
remain  to  praise  it.  And  I  have  thought 
since  that  whatever  fame  Mr.  Lacault 
has  gained  in  the  past  will  be  small  com- 
pared to  that  he  will  gather  in  the  future. 
I  couldn't  help  but  form  a  contrast 
at  the  time  for  it  came  to  me  that  the 
new  Ultradyne  no  more  resembles  the 
old  type  than  the  original  Edison  Talk- 
ing Machine  resembles  the  present  day 
Victrola.  This  contrast  entered  my 
mind  first,  I  believe,  because  the  me- 
chanical appearance  of  the  usual  type 
of  radio  set  has  been  entirely  removed 
from  the  new  Ultradyne.  It  is  more 
ike  a  nice  piece  of  furniture  than  an 
electrical  instrument  and  from  its  beauty 
of  type  and  broad  adaptability  to  design, 
I  would  say  that  one  could  put  it  where 
one  pleased  without  the  slightest  worry 
of  its  clashing  in  any  way  with  the  scheme 
of  a  room. 

General  Refinements 

The  front  view  photograph  of  the  new 
Ultradyne  shown  herewith  reveals  more 
than  words  possibly  could,  still  there  is 
much  that  cannot  be  seen  well  and  quite 
a  bit  that  cannot  be  seen  at  all,  so  a 
description  is  required  if  I  am  to  do  the 
set  justice. 

First  of  all,  let  me  say  that  the  set  is 
as  near  to  being  automatic  in  operation 
as  is  possible  to  make  one  under  present 
limited  circumstances.  I  believe  this 
to  be  true  under  the  consideration  that 
there  are  three  stages  of  radio  frequency 
amplification  to  contend  with.  And 
doesn't  it  look  automatic  if  we  judge  by 
the  absence  of  knobs  and  dials?  There  is 
a  small  knob,  placed  at  the  lower  right 
of  the  cabinet  front,  but  it  has  nothing 
to  do  with  tuning.     Rather,  it  controls 

*     Tested  and  Approved  by  RADIO  AGE     * 


the  volume.  When  turned  full  to  the 
left  it  cuts  off  the  current  to  the  filaments 
of  the  vacuum  tubes  and  this  is  all  that 
is  necessary  to  do  to  "turn  things  off." 
A  small  jack  at  the  lower  left  on  the 
cabinet  front  balances  up  with  the 
volume  control  and  is  there  should  you 
care  to  use  head-phones. 

This  set,  being  knobless,  is  also  dial- 
less,  though  there  is  a  large  but  un- 
obtrusive scale  bordering  the  circular 
grill,  in  the  center.  This  scale  is  the 
determining  factor  for  all  stations  one 
wishes  to  receive.  There  are  no  wave- 
length, frequency  or  station  markings 
on  this  scale  whatsoever.  Who  would 
desire  to  mark  a  fine  piece  of  furniture 
or  a  phonograph  with  numbers  or  letters, 
done  free-hand,  excepting  for  the  mo- 
ment that  there  was  some  reason  for 
doing  so,  when  the  manufacturer  could 
have  provided  other  and  simpler  means 
in  the  first  place?  In  other  words,  why 
make  it  necessary  for  the  owner  to  detract 
from  the  beauty  of  a  radio  set  made  to 
be  beautiful  when  a  simple  chart  can  be 
provided  to  do  the  trick  just  as  well  and 
just  as  rapidly?  That  is  the  system 
worked  out  for  the  new  Ultradyne. 
There  are  two  levers,  which  are  out  of 
sight,  but  whose  ends  terminate  in  con- 
venient grasping  handles. 

Their  path  is  along  the  large  scale. 
They  are  the  station  selectors  and  it's 
as  simple  as  falling  off  a  log  to  handle 
them.  There  is  no  "cramping"  of  sta- 
tions within  a  few  degrees  on  the  scale, 
nor  any  of  the  usual  critical  adjustments 
found  necessary  in  the  common  type  of 
receiver.  All  you  have  to  do  is  to  grasp 
the  lever  ends  and  move  them  down 
slowly  until  you  have  the  station  you 
want. 

Another  feature  of  the  new  set  is  the 
position  of  the  loud  speaker.  It's  right 
in  front  of  your  nose  so  to  speak,  or  to 
be  more  specific,  directly  behind  the 
circular  grill.  This  grilling,  by  the  way, 
is  given  a  statuary  bronze  finish  and  is 
backed  by  a  screening  of  dull  gold.  The 
whole  blends  well  with  the  cabinet  which 
is  made  of  five  ply  mahogany  veneer 
with  a  two  tone  line  cutting. 

Technical  Specifications 

The  new  Ultradyne  employs  six  tubes 
of   the   storage    battery   type,    three   of 
them,   as  mentioned  before,  functioning 
(Turn  to  next  page) 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


57 


as  radio  frequency  amplifiers,  the  fourth 
as  the  detector  and  the  last  two  as  the 
audio  frequency  amplifiers.  Two  of  the 
radio  frequency  stages  are  tuned,  while 
the  third  stage  is  fixed.  In  connection 
with  the  radio  frequency  amplifier  unit 
Mr.  Lacault  has  killed  two  birds  with 
one  stone.  The  "stone"  amounts  to  two 
resistances  included  in  two  of  the  grid 
or  input  circuits  of  the  radio  frequency 
tubes.  They  prevent  these  circuits  from 
oscillating  or  "spilling  over"  at  resonance 
points  and  at  the  same  time  actually 
increase  the  selectivity  of  the  entire  radio 
frequency   amplifier. 

Then,  there  is  the  matter  of  the  con- 
densers employed  in  the  new  Ultradyne 
that  have  made  the  improved  tuning 
system  possible.  They  are  the  now  well 
known  Ultra-Lowloss  variable  condens- 
ers with  a  "straight  line  wavelength 
curve."  With  such  a  type  condenser, 
the  wavelength  is  distributed  evenly 
over  the  entire  scale  reading;  that  is  to 
say,  one  hundred  meters  or  so  are  not 
crammed  in  a  relatively  small  space  on 
the  scale.  Thus,  cramping  of  stations 
within  a  small  degree  reading  is  elimin- 
ated. 

In  the  new  Ultradyne  the  loud  speaker 
unit  is  electrically  matched  with  the 
audio  frequency  amplifier  so  that  the 
impedance  of  both  is  the  same.  This 
does  wonders  yet  there  is  nothing  so 
complicated  about  the  system;  it  comes 
to  me,  in  fact,  that  there  is  nothing 
complicated  about  any  of  the  little 
schemes  Mr.  Lacault  works  out.  He 
seems  to  have  the  faculty  of  solving  an 
abstruse  problem  in  a  very  simple  way. 
The  volume  is  as  much  as  any  normal 
soul  would  ask  for.  The  set  will  not 
entertain  the  people  on  the  next  block, 
perhaps,  but  then  it  is  not  built  to  be  a 
public   address   system. 

I  think  I  have  mentioned  that  the 
new  Ultradyne  is  self  contained.  The 
"B"  batteries  fit  in  the  cabinet  to  the 
side  of  the  instrument  framework  and 
connect  to  binding  posts  on  the  side  of 
the  sub-base  which  carries  the  vacuum 
tube  sockets  and  automatic  filament 
controls.  Four  posts  are  mounted  to 
the  rear  of  this  base  for  the  "A"  battery, 
aerial  and  ground  connections  which  are 
run  to  them  through  holes  in  the  rear 
of    the    cabinet. 


A  Resistance  Coupled 
Amplifier 

The  Allen-Bradley  Company  of  Mil- 
waukee has  developed  a  Resistance 
Coupled  Amplifier  that  amplifies  all  tones 
proportionately  and  does  not  distort. 
The  Bradley-Amplifier,  as  it  is  called,  is 
compactly  designed  and  so  small  in  size 
that  it  may  be  conveniently  installed  in 
place  of  transformer-coupled  amplifiers 
in  factory  built  sets.  All  wiring,  resistors, 
and  condensers  are  contained  in  a  highly 
polished  Bakelite  base.  Only  the  tube 
sockets  and  terminals  extend  above  the 
base. 

The  resistors  used  in  the  Bradley- 
Amplifier  are  Bradlev-units  (moulded 
resistors).  Since  Bradley  units  are  im- 
pervious to  moisture  and  atmospheric 
changes,  and  are  not  affected  by  age  or 
service,  the  Bradley-Amplifier  retains 
its  marvelous  tone  quality  even  after 
many  years  of  service.  All  joints  inside 
the  Bradley-Amplifier  are  soldered  to 
assure  perfect  contact.  The  tube  sockets 
are  designed  to  hold  the  new  UX  tubes 
as  well  as  tubes  of  the  UV  201-A  type. 
Only  the  UV- 199  tubes  require  an  adaptor 
Tube  contacts  are  silver  plated,  and  so 
designed  that  positive  contact  is  assured. 


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NOW  you  can  build  a  set  and  have  all  three  tuning 
dials  tune  exactly  the  same — or,  you  can  build  a 
one  control  set  using  a  gang  condenser  and  know  that 
it's  going  to  work  right.  AERO  Coils  are  matched! 

But— the  matched  feature  of  Aero  Coils  is  not  their 
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Aero  Coils  are,  by  electrical  measurement  and  by  use 
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A  five  tube,  improved  tuned  radio 
frequency  receiver,  known  as  the 
RADIO  AGE  MODEL  RECEIVER,  to  be 
described  in  the  December  RADIO  AGE, 
will  be  given  away  at  the  Fourth  Annual 
Radio  Show  in  Chicago  during  November. 
See  details  on  page  20,  this  i3sue. 


RAULF! 


RADIO  CONSOLE 

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*     Tested  and  Approved  by  RADIO  AGE     * 


— Radio  Nut's  Headquarters — Parts  only,  no 
sets.  $20,000  stock.  Most  comprehensive.  If 
you  can't  find  it,  ask  us.  Weekly  latest 
"dope" — 10  wks.  50c.  "Change  your  Neut" 
Kit — $5  prepaid.  Particulars — 10c.  48  page 
parts  catalog — 10c.  Knock  Down  Loop  Kit — 
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110  v.  a.  c,  knock  down  kit  including  2000 
hr.  Z  50  tube — $36.55.  Assembled,  ready  to 
use — $40.  Data — 10c.  Kladag  Radio  Labora- 
tories,   Kent,    Ohio. 


58  RADIO  AGE  for  November,  1925 

WITH 


The  Magazine  of  the  Hour 

URERS 


Fans — Here's   the  Amsco 

The  Amsco  Compensating  Condenser 
is  a  three  electrode  Condenser  and  is  so 
designed  that  it  will  not  detune  the 
radio-frequency  transformers  while  ad- 
justing to  eliminate  the  feedback  or  re- 
generation. 

The  Amsco  Compensating  Condenser 
is  mainly  constructed  for  the  purpose  of 
balancing  the  grid  charge  on  the  Amplify- 
ing Tubes.  It  stops  all  local  oscillations 
without  detuning  the  amplifier.  It  is 
shielded  against  hand  capacity  disturb- 
ances. It  makes  it  easy  for  the  operator 
to  find  the  correct  capacity  because  of 
the  circuits  always  being  tuned.  It  is 
the  third  electrode  in  the  Amsco  Com- 
pensating Condenser  that  makes  this  a 
clean-cut  and  straightforward  adjust- 
ment. 

The  compensating  condenser  for  the 
last  stage  in  particular  may  be  varied 
so  that  the  receiver  can  be  used  efficiently 
for  C.  W.  reception,  or  it  may  be  only 
slightly  unbalanced  so  as  to  give  sharper 
tuning  characteristics  to  each  stage  in 
the    set. 

The  ideal  set  using  tuned  radio-fre- 
quency transformer  amplification  must 
have  a  variable  compensating  con- 
denser in  order  to  eliminate  the  regenera- 
tion due  to  tube  capacity. 

The  "V.  T.-l"  or  "J"  tubes  have 
nearly  three  times  the  capacity  between 
the  grid  and  plate  that  the  Radiotron 
tubes  have  so  that  a  greater  variation  is 
necessary. 


Radio    Battery    Cable    Made 
by  Belden 

The  Belden  Manufacturing  Company, 
2300  South  Western  Avenue,  Chicago, 
Illinois,  has  recently  placed  a  battery 
cable  on  the  market  that  is  very  similar 
to  the  well  known  and  universally  used 
Belden  Radio  Battery  Cord.  It  is  sup- 
plied in  100  foot  lengths  on  spools,  or 
200-foot  lengths  in  coils,  and  can  thus  be 
cut  to  any  special  length  that  the  oc- 
casion   requires. 

The  cable  consists  of  2  No.  16  B.  &  S. 
stranded  and  3  No.  20  B.  &  S.  stranded 
copper  conductors,  each  rubber  covered 
and  insulated  with  individually  colored 
cotton  braid,  coded  in  accordance  with 
the  standard  of  the  A.  M.  E.  S.  The 
entire  unit  is  then  encased  in  a  heavy, 
black,  glazed  cotton  braid  cover. 

The  cable  is  used  when  it  is  desirable 
or  necessary  to  isolate  the  batteries  from 
the  set,  by  placing  them  in  the  basement 
or  in  a  similarly  remote  location.  The 
difficulty  usually  encountered  in  tracing 
a  maze  of  tangled,  unsightly  wires  from 
battery  to  set  is  thus  eliminated.  The 
colored  tracers  simplify  the  checking  of 
connections  and  insure  absolute  ac- 
curacy in  the  hook-up.  Blown-out 
tubes,  crossed  wires,  short  circuits  and 
wrong  connections  are  entirely  disposed 
of  by  the  use  of  this  cable. 


Describing  Eagle  Radio  Co.'s 
Latest  Neutrodyne 

The  Eagle  Radio  Company's  new 
neutrodyne  receiver  is  twenty-two  inches 
long,  eight  and  three-quarters  inches 
high.  The  black  Bakelite  panel  is  finished 
with  gold  trimmings  and  lettering.  The 
battery  switch  and  phone  jack  are  also 
of  gold.  The  set  is  designed  to  operate, 
with  five  201  A  or  301  A  tubes,  or  with 
four  201  A  or  301  A  tubes  and  one  power 
tube. 

Other  striking  points  of  improvement 
in  the  new  Eagle  model  F,  are,  first: 
radio  frequency  coils. 

These  coils  are  a  radical  departure 
from  the  conventional  type.  The  w:re 
on  both  primary  and  secondary  is  space 
wound  on  very  thin  cylinders  of  cellulose 
acetate.  The  high  frequency  resistance 
and  distributed  capacity  is  lower  by 
actual  measurement  than  on  any  other 
type  of  commercially  adaptable  coils. 
This  means  a  greater  ability  to  receive 
stations  on  the  lower  wave  lengths  than 
we  have  hitherto  been  able  to  accomplish 
in    any    neutrodyne    receiver. 

Second  is  volume  control. 

Instead  of  a  switch  which  changes 
from  first  stage  to  second  stage,  the  Eagle 
model  F  resistance  is  across  the  second- 
ary to  the  second  audio  frequency  trans- 
former. This  permits  a  gradual  regula- 
tion of  volume  instead  of  the  two  jumps 
which  is  obtained  with  a  switch.  This 
resistance  also  acts  as  a  protection  to  the 
quality. 

In  the  model  F  the  rheostats  are 
changed  so  that  one  controls  the  radio 
frequency  tubes  and  the  other  the  audio 
frequency  tubes.  The  detector  has  been 
placed  on  an  automatic  filament  control. 
With  this  change  the  sensitivity  and 
clarity  can  be  adjusted  to  the  best  point 
much  more  easily  than  previous  rheostat 
systems. 

The  dials,  which  are  of  Bakelite,  have 
been  changed  to  the  concealed  type  and 
geared  down  to  a  S  to  1  ratio  making 
fine  tuning  very  easy. 

The  company  has  an  exceptionally 
fine  line  of  consoles  in  either  mahogany 
or  walnut  finish  with  battery  compart- 
ments, and  built-in  loud  speaker  horns. 


J.  L.  Polk  Designs  a 
Binding  Post 

_  Somewhat  on  the  order  of  a  spring 
binding  post  is  the  latest  product  turned 
out  by  J.  L.  Polk,  443  South  Madison 
Ave.,  La  Grange,  111.  The  binding  post 
which  was  submitted  has  been  tested 
and  approved  by  the  Radio  Age  Institute. 


Saturn  Co.  Puts  Out  Extension 
Cord  Connector 

Radio,  having  passed  the  experimental 
stage,  progressive  firms  like  the  Saturn 
Mfg.  &  Sales  Co.,  of  48  Beekman  Street, 
N.  Y.  City,  are  concentrating  on  equip- 
ment to  eliminate  the  unsightliness  of 
connections  and  are  producing  parts 
that  are  good  to  look  at  as  well  as  useful. 

One  of  the  latest  products  of  this  firm 
is  The  Saturn  Extension  Cord  Connector 
with  which  owners  of  receivers  may  move 
their  ear  phones  or  loud  speakers  to 
different  parts  of  the  house  or  rooms. 
In  case  of  illness,  the  chap  who  must 
stay  in  bed  for  a  time,  need  not  be  de- 
prived of  the  pleasure  to  be  derived  from 
the  air  programs;  also,  the  family  at 
dinner  can  bring  the  metropolitan  or- 
chestra music  right  up  to  the  table. 
There  are  numberless  ways  in  which  this 
latest  addition  to  radio  will  be  a  help 
and  advantage  to  the  fan. 

The  Saturn  Connector  is  of  hard 
rubber,  neatly  constructed,  with  the 
positive  and  negative  cords  in  different 
colors,  easily  differentiated,  and  ter- 
minals that  fit  snugly  into  place.  With 
this  connector,  and  as  many  extra  feet 
of  cord  as  are  desired,  a  very  neat  look- 
ing extension  can  be  made. 


THE  LEADER  OF  THEM  ALL! 

The  New  Radio  Age  Receiver — 
in  December 


Connewey    Now    Located    in 
Magnatron  Bldg. 

The  Connewey  Electric  Laboratories 
have  taken  possession  of  their  mammoth 
new  fireproof  and  sanitary  plant  at  406- 
408  Jefferson  Street,  Hoboken,  New 
Jersey.  The  structure  will  be  known  as 
the  Magnatron  Building.  The  building 
has  been  entirely  reconstructed  to  fit 
every  detail  in  the  manufacture  of  Mag- 
natron Tubes  and  will  vastly  increase 
production. 

The  New  Magnatron  Plant  has  been 
almost  entirely  refitted.  New  machinery 
was  installed  in  every  department  and 
the  latest  appliances  necessary  for  the 
manufacture  of  their  product  were  pur- 
chased. Everything  was  done  to  make 
the  structure  one  of  the  most  modern 
of  its  kind.  Clean,  wholesome  working 
conditions  and  plenty  of  room  to  do 
efficient  work  has  been  provided  for  the 
employes. 

To  the  Connewey  Electric  Labora- 
tories goes  the  honor  of  being  the  first  to 
develop  a  vacuum  tube  especially  for 
B  Battery  eliminators.  This  new  tube, 
known  as  the  "REX,"  has  proved  more 
than  successful  in  a  series  of  exhausting 
tests  conducted  at  the  new  factory  and 
in  outside  laboratories. 

The  "REX"  is  manufactured  with  a 
standard  bakelite  base,  so  that  it  will 
fit  all  present  standard  sockets.  The 
bulb  itself  is  round  in  shape  and  of  such 
size  as  to  quickly  dissipate  the  heat 
generated  during  operation.  The  base 
carries  the  usual  four  prongs,  although 
only  three  of  them  are  used  in  the  circuit. 


RADIO  AGE  for  November,  1925  The  Magazine  of  the  Hour  59 

Official  Show  of  Radio  Manufacturers'  Association 


o»Ttl«ud 


zmm^m&w 


RADIO  SHOW 

Kit         Coliseum 
P    JTovember  17th  to  22nd 

»\esdi#i0Siwti9M$ttlrwhmfolMUntilllPM. 


"A  Radio 


Fair 


127  No.  Dearorn  Street 

Chicago,  Illinois 


U.  J.  Herrmann,  Managing  Director 
G.  Clayton  Irwin,  Jr.,  General  Manager 

Business  Office: 

RADIO  MANUNACTURERS' 
SHOW  ASSOCIATION 


611  Times  Bldg. 
New  York  City 


Including 
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Positively. — > 

More  Stations 

if  you  use  a 

BARRETT  &  PADEN 

Micrometer  Condenser 

|  (For  any  type  of  Set) 


j 

Stra 

gl 

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it  Line  Wave 

Le 

agth 

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Flat  Wave  Length  Curva 


A  RECEIVER  cannot  bring  in  a 
f-\  station  unless  it  is  tuned  into 
•*■  *•  resonance  with  that  station. 
There  are  many  stations  which  you 
have  not  been  able  to  receive  be- 
cause the  condensers  in  your  set  did 
not  have  a  sufficiently  wide  range  of 
minute  capacity  variations  to  enable 
you  to  tune  enough  separate  and 
distinct  resonance  points.  No  matter 
how  finely  you  try  to  tune  with  your 
present  condensers  you  skip  these 
signals — because  their  tuning  range 
is  limited. 

Install  Barrett  &.  Paden.  Microm- 
eter Type  Condensers  and  bring 
in  the  weak  distant  stations  with  loud 


speaker  volume!  The  micrometer 
action  of  the  Barrett  St  Paden  when 
applied  to  its  broad  capacity  range, 
enables  you  to  find  the  exact  reso- 
nance points  of  many  stations  which 
with  other  condensers  are  so  close  to 
interfering  stations  that  separation 
is  impossible. 

You  will  be  amazed  at  the  tremen- 
dous immediate  difference  these 
condensers  will  make  in  the  perfor- 
mance of  your  set.  They  not  only 
will  give  you  more  stations,  by  rea- 
son of  their  micrometer  action,  but 
because  of  their  lower  loss  will 
appreciably  increase  the  strength 
with  which  signals  are  reproduced. 


At  your  dealers  or  direct 

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Town 


Tuned    and    Untuned    R.    F. 
Linked 

For  the  first  time  in  radio  history, 
tuned  and  untuned  radio  frequency  have 
been  successfully  linked.  It  has  been 
done  by  William  H.  Priess  and  the  engi- 
neers assisting  him. 

When  the  experiments  leading  to  this 
result  were  begun,  they  were  with  the 
thought  of  commercial  application  in 
mind.  Pure  research  at  no  time  entered 
the  minds  of  the  experimenters.  How 
successfully  the  result  worked  out  was 
shown  «n  the  demonstration  of  the  re- 
ceiving set  at  the  Radio  World's  Fair  in 
New  York  last  week. 

Radio  scientists  have  long  desired  to 
combine  tuned  with  untuned  radio 
frequency,  but  the  difficulties  that  had 
to  be  faced  narrowed  the  experimenta- 
tion almost  to  a  minimum.  Priess  has 
done  it  and  as  a  result  achieves  an  ampli- 
fication that  is  simply  enormous. 

As  is  generally  known,  the  distance 
reception  property  of  any  set  is  depend- 
ent upon  the  voltage  amplification  that  it 
delivers  at  radio  frequency  prior  to  the 
detector  tube.  The  average  five  tube 
set  rarely  delivers  in  excess  of  400.  By 
combining  tuned  and  untuned  radio 
frequency,  the  Priess  method  reaches  an 
amplification  value  of  3000  before  the 
detector  tube.  Its  effect  on  distance- 
getting    is    obvious. 

The  Priess  method  employs  five  stages 
of  radio  amplification,  one  of  which  is 
tuned.  The  output  of  the  fifth  tube  is  fed 
into  a  detector.  The  power  output  of  the 
detector  is  amplified  through  two  suc- 
cessive stages  of  audio  frequency  ampli- 
fication. The  volume  yield  equals  that 
of  a  phonograph  playing  with  a  loud 
needle. 


Bosch  Magneto  Co.  Devises  a 
Hydrometer 

A  new  hydrometer  of  unusually  excel- 
lent and  compact  construction  has  just 
been  placed  on  the  market  by  the  Robert 
Bosch  Magneto  Company  of  New  York, 
manufacturers  of  Bosch  magnetos  and 
other  electric  automotive  equipment. 

In  addition  to  long  life  which  is  insured 
by  the  high  quality  of  the  rubber  parts 
and  the  uniform  strength  of  the  glass 
used,  the  manufacturers  claim  several 
unique  features  of  mechanical  superiority. 
Among  these  is  a  "non-drip"  construc- 
tion which  traps  any  liquid  remaining 
in  the  barrel  after  use,  and  prevents  acid 
being  dripped  on  clothes  or  rugs.  Other 
features  are  extremely  plain  markings 
which  make  readings  easy  to  take,  a 
lively  bulb  which  responds  to  the  slight- 
est pressure;  and  glass  tips  which  hold 
the  float  in  easy  sliding  position  so  that 
it  cannot  stick  in  the  barrel. 

Although  on  the  market  but  a  short 
time,  this  new  product  is  being  purchased 
widely  both  by  car  owners  and  radio 
enthusiasts. 


Radio  Advertisers'  Data  Issued 
by    Rosenberg 

The  1925-1926  Radio  Advertisers' 
Data  Book,  a  volume  of  rates  and  other 
information  for  national  advertisers, 
has  just  been  issued  by  its  publishers, 
Arthur  Rosenberg  Co.  Inc.,  New  York. 

Several  features  which  were  not  in  the 
1924  issue  have  been  included  in  the 
current  edition.  The  contents  include 
advertising  rates,  circulation  and  other 
data  regarding  Radio  Consumer  and 
Trade  publications,  as  Well  as  of  all  the 
periodicals  of  the  allied  trades,  including 
Automotive,  Electrical,  Hardware,  Mus- 
ic, Talking  Machine  and  Sporting  Goods. 

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THE  BEST  RADIO  APPARATUS 
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A  Super  Without  the 
I.  F.  Stages! 

(Continued  from  page  10) 

readjust  dials  (C1-C2)  for  maximum 
results  and  then  re-adjust  (Kl)  for  the 
required  volume  and  to  clear  up  any 
distortion  or  mush  that  may  be  present. 
The  radio  frequency  transformer 
(RFT),  also  known  as  the  "filter  coil," 
is  adjustable  by  sliding  the  primary 
coil  back  and  forth  on  a  brass  rod  in  re- 
lation to  the  secondary  coil.  In  effect, 
this  adjustment  is  similar  to  the  adjust- 
ment of  a  vario-coupler,  for  it  controls 
the  degree  of  coupling  between  the  pri- 
mary and  secondary  circuits  and  hence 
determines  the  selectivity.  With  the 
primary  close  to  the  secondary,  the  tun- 
ing will  be  broader  and  the  set  will  be 
less  selective  than  when  the  coils  are 
farther  apart,  therefore  the  adjustment 
affords  a  means  of  varying  the  selectivity 
in  accordance  with  local  interference, 
and  after  the  adjustment  is  made  after 
an  installation,  the  coil  is  locked  in  place 
and  no  further  adjustment  is  necessary 
until  the  set  is  moved  or  changes  are 
made  in  the  antenna  construction. 

With  strong  signals  which  cause  over- 
loading of  the  last  audio  tube,  and  there- 
fore produce  howling,  adjusting  the 
resistance  knob  (r)  will  stop  the  howl. 
If  a  carbon  disc  type  of  resistance  is  used, 
screwing  down  the  knob  will  reduce  the 
resistance  and  the  overloading.  Unscrew- 
ing the  knob  increases  the  resistance  and 
also  the  volume  on  weak  stations.  This 
adjustment  is  not  critical,  and  needs  no 
adjustment  over  a  wide  range  of  volumes, 
but  when  a  strong  local  is  tuned  in,  it 
may  be  necessary  to  unload  the  tube. 
The  grid  condenser  for  a  201A  tube  it 
normally  0.00025  mf.  capacity,  while  the 
leak  value  will  range  from  1.0  to  2.0 
megohms.  Experiment  will  show  the 
proper  leak  value  to  use,  but  in  any  case 
it  is  not  critical. 

The  usual  length  of  antenna,  from  60 
to  75  feet  long,  is  used  with  this  super- 
heterodyne. Longer  aerials  are  not 
recommended. 


"Roxy"  on  Way  Back  to  His 
Admirers 

S.  L.  Rothafel,  famous  "Roxy"  of 
radio,  will  soon  return  from  a  European 
trip  and  early  next  season  make  his  en- 
trance as  a  director  of  his  own  Theatre  in 
New  York  City. 

Mr.  Rothafel  is  not  only  a  great 
announcer  of  radio  concerts — gifted  with 
the  power  of  injecting  his  personality 
over  the  ether — but  there  is  no  more 
enthusiastic  listener  on  the  radio  than 
"Roxy."  He  takes  great  pride  in  the 
wonderful  log  of  stations  that  he  has 
received  on  several  receiving  sets. 

When  he  went  to  Europe  on  the  "Le- 
viathan" he  took  with  him  a  Freed- 
Eisemann  5-tube  radio  frequency  portable 
receiver  and  used  this  on  his  travels  on 
the  continent. 

On  the  trip  home  he  will  "listen  in"  to 
the  "Gang"  from  the  Capital  on  the 
same  receiver. 


Read  Radio  Age 

*     Tested  and  Approved  by  RADIO  AGE     * 


The  Magazine  of  the  Hour  61 

Rhamstine* 
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504  E.  Woodbridge, 
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your  "B"  Rectifier  at  $25. 

by  express  C.  O.  D„  subject  to  inspection.  If  not 
entirely  satisfied  with  the  "B"  Rectifier  I  will  return 
it  to  you  in  five  days  and  receive  a  refund  of  full 
purchase  price. 

Name 

Address 


J.  THOS.  RHAMSTINE* 

Radio  and  Electrical  Products 
504     E.     Woodbridge Detroit,     Mich. 

NEW  BIG  POWERFUL  M  T  ■£  .  HfcB^ 

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RADIO 

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COASTS) 
COAST 


62 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


Now  you  can 

UNDERSTAND 

RADIO! 

514  PAGES 


* 


i.cs. 
RADIO 

HANDBOOK 


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100,000 
SOLD 

Compiled  by 
HARRY  F.  HART 
E.E. 
Formerly  witb 
the  Western 
Electric  Co., 
and  U.  S. 
Army  In- 
structor of 
Radio.  Tech- 
nically edited 
byF.H.Doaae. 

More  than  100,000  radio  fans  rely  on  thia 
I.  C.  S.  Radio  Handbook  to  take  the  mystery- 
out  of  radio.  Why  experiment  in  the  dark 
when  you  can  quickly  learn  the  things  that 
insure  success  ?  Hundreds  of  illustrations 
and  diagrams  explain  everything  so  you  can 
get  the  most  out  of  whatever  receiver  you 
build  or  buy. 

Contents :  Electrical  terms  and  cir- 
cuits, antennas,  batteries,  genera- 
tors and  motors,  electron  (vacuum) 
tubes,  most  receiving  hook-ups, 
radio  and  audio  frequency  amplifi- 
cation, broadcast  and  commercial 
transmitters  and  receivers,  wave 
meters,  super-regeneration,  codes, 
license  rules.     Many  other  features. 

A  practical  book.  Written  by  experienced 
radio  engineers,  in  plain  language.  Some- 
thing useful  on  every  one  of  its  514  pages. 
A  book  that  will  save  you  many  times  its 
small  cost. 

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SCHOOLS 
Box  878 1 -E,  Scranton,  Penna. 

I  enclose   § for  which  send  me,   post-paid, 

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stood that  if  I  am  not  entirely  satisfied  I  may 
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□  RADIO   HANDBOOK,   514  PAGES, 

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□  Electrical  Handbook,   414  pages  -     -     -  -  S 

□  Chemistry  Handbook,  34  8  pages  -  -  -  § 
D  Pharmacy  Handbook,  324  pages  -  -  -  5 
D  Traffic  Handbook,  386  pages  -  -  -  -  $ 
D  Building  Trades  Handbook.  40  9  pages  -  -  5 
D  Machine  Shop  Handbook,  335  pages  -  -  I 
G  Salesman's  Handbook,  3  52  pages  -  -  -  § 
G  Advertising    Handbook.    445    pages     -      -  -  5 

□  Bookkeeper's     Handbook,     3  02     pages  § 

B  Civil  Engineer's  Handbook,   411   pages  -  -  5 

Steam  Engineer's  Handbook,  298  pages  -  | 


Enclose  SI. 50  instead  of  $1  for  each  look  if  you 
want  the  Leather&id  binding.  All  of  the  above 
books  can  be  hcd  in  this  binding  except  the  Traffic 
Handbook  and  the  Building  Trades  Handbook, 


Real  Radio  Apparatus 

for  Subscriptions  to 

Radio  Age! 

Something  New  in  Prizes 

for  Readers! 

See  Announcement 

in  this  Issue 


The  Magnetic  Theory  of 
Transmission 

{Continued  from  page  50) 

quiet  day  than  on  a  windy  day  when  the 
air  is  in  violent  motion.  Why  would  not 
the  same  be  true  of  radio  transmission? 
The  magnetic  field  of  the  earth  is  con- 
stantly changing  during  daylight  and  is 
comparatively  calm  at  night. 

Recent  experiments  have  shown  that 
short  wave,  or  high  frequency  transmis- 
sion, gives  much  better  results  than  long 
wave  or  low  frequency  transmission  for 
daylight  work.  It  is  possibly  that  the 
high  frequency  waves  are  so  rapid  that 
they  are  not  affected  so  much  by  the 
natural  daylight  oscillations  in  the  earth's 
magnetic  field. 

The  magnetic  field  of  the  earth  has 
been  found  to  be  strongest  and  most 
uniform  during  the  months  from  October 
to  March,  during  which  time  the  earth  is 
two  million  miles  or  more  nearer  the  sun 
than  in  June.  During  these  months  our 
radio  reception  is  at  its  best.  What  is 
the  nature  of  the  reception  during  these 
months  in  the  Southern  Hemisphere? 
An  answer  to  this  question  would  be 
interesting. 

A  comparison  of  radio  transmission 
conditions  with  conditions  of  the  mag- 
netic field  of  the  earth  during  its  daily  and 
annual  changes  gives  us  very  strange 
coincidences  if  radio  does  not  depend  on 
the  magnetic  field  of  the  earth  as  the 
means  of  its  transmission. 

The  observations  of  the  earth's  mag- 
netic field,  upon  which  the  above  state- 
ments are  based,  were  made  about  sixty 
years  ago,  the  results  of  which  were 
published,  in  part  at  least,  in  1870  by 
George  B.  Airy,  Professor  of  Astronomy 
at  Cambridge  University. 


STATEMENT  OF  THE  OWNERSHIP,  MANAGEMENT, 
CIRCULATION,  ETC.,  REQUIRED  BY  THE  ACT  OF 
CONGRESS  OF  AUGUST  24,  1912, 

Of  RADIO  AGE,  published  Monthly  at  Mount  Morris,  Illinois, 
for  October.  1925. 

State  of  Illinois,    \ 
County  of  Cook     J  s3' 

Before  me,  a  Notary  Public  in  and  for  the  State  and  county 
aforesaid,  personally  appeared  Frederick  A.  Smith,  who, 
having  been  duly  sworn  according  to  law,  deposes  and  says 
that  he  is  the  President  of  the  RADIO  AGE  and  that  the 
following  is,  to  the  best  of  his  knowledge  and  belief,  a  true 
statement  of  the  ownership,  management  (and  if  a  daily 
paper,  the  circulation) ,  etc,  of  the  aforesaid  publication  for  the 
date  shown  in  the  above  caption,  required  by  th  Act  of 
August  24,  1912,  embodied  in  section  411,  Postal  Laws  and 
Regulations,  printed  on  the  reverse  of  this  form,  to  wit: 

1.  That  the  names  and  addresses  of  the  publisher,  editor, 
managing  editor,  and  business  managers  are:  Publisher, 
RADIO  AGE,  Inc.,  F.  A.  Smith,  President,  500  N.  Dearborn 
St.,  Chicago,  111.:  Editor,  Frederick  A.  Smith,  500  N.  Dearborn 
St..  Chicago,  IU.:  Managing  Editor.  Frederick  A.  Smith, 
500  N.  Dearborn  St.,  Chicago,  111.;  Business  Managers,  M.  B. 
Smith,  500  N.  Dearborn  St.,  Chicago,  111. 

2.  That  the  owners  are:  RADIO  AGE,  Inc.  ,500  N.  Dear- 
bom  St.,  Chicago.  111.:  Frederick  A.  Smith,  500  N.  Dearborn 
St..  Chicago.  IU.:  M.  B.  Smith.  500  N.  Dearborn  St.,  Chicago. 
111.:  J.  H.  Lohbeck,  6429  Cates  Ave..  St.  Louis,  Mo. 

3.  That  the  known  bondholders,  mortgagees,  and  other 
security  holders  owning  or  holding  1  per  cent  or  more  of  total 
amount  of  bonds,  mortgages,  or  other  securities  are:  (If  there 


4.  That  the  two  paragraphs  next  above,  giving  the  names 
of  the  owners,  stockholders,  and  security  holders,  if  any. 
contain  not  only  the  list  of  stockholders  and  security  holders 
as  they  appear  upon  the  books  of  the  company  but  also,  in 
cases  where  the  stockholder  or  security  holder  appears  upon 
the  books  of  the  company  as  trustee  or  in  any  other  fiduciary 
relaUon,  the  name  of  the  person  or  corporation  for  whom 
such  trustee  is  acting,  is  given:  also  that  the  said  two  para- 
graphs contain  statements  embracing  affiant's  full  knowledge 
and  belief  as  to  the  circumstances  and  conditions  under  which 
stockholders  and  security  holders  who  do  not  appear  upon  the 
books  of  the  company  as  trustees,  hold  stock  and  securities  in 
a  capacity  other  than  that  of  a  bona  fide  owner;  and  this 
affiant  has  no  reason  to  believe  that  any  other  person,  associa- 
tion, or  corporation  has  any  interest  direct  or  indirect  in  the 
said  stock,  bonds,  or  other  securities  than  as  so  stated  by  him. 
FREDERICK  A.  SMITH. 


Sworn  to  and  subscribed  before 
ber.  1925. 
[Seal.] 

(My 


j  this  29th  day  of  Septem- 

HARRIET  DILLON. 
>ires  June  7,  1927.) 


A  Real  Long  Range 

Crosley  Receiving 

Set,  $9.75 

Do  not  assume  from  its  very  interesting 
price  that  this  very  unusual  Crosley 
set  is  a  toy.  Its  impressive  performance 
alone  entitles  it  to  serious  consideration. 
Heretofore,  the  $  1 0  radio  was  designed  only 
for  local  reception.  Now  the  Crosley 
Pup  extends  the  entertainment  radius 
to  1500  miles  under  ordinary  conditions. 
Place  it  beside  some  costly  multiple- 
tube  set  and  operate  the  dials.  Both 
tune  through  local  stations  sharply. 
Both  get  the  same  programs  with  equal 
ease  and  clarity.  Both  let  you  tap  the 
infinite  enjoyment  coming  through  the 
air.  There  is  only  one  difference— the 
Pup  operates  with  head  phones  instead 
of  a  loud  speaker. 

Almost  overnight  the  Pup  has  become 
the  most  popular  Crosley  set  ever  offered. 
It  is  being  bought  for  youngsters  whose 
curious  fingers  cannot  resist  the  lure 
of  dials  and  switches;  for  the  cook,  the 
maid,  the  old  folks  back  home,  and  for 
shut-ins.  Traveling  men  are  selecting 
it  because  of  its  easy  portability,  and 
radio  enthusiasts  to  have  an  inexpensive 
check  on  their  larger  sets.  Hear  it  once — 
and  you  will  own  one  too! 

Crosley  manufacturers  receiving  sets  which 
are  licensed  under  Armstrong  U.  S. 
patent  No.  1,113,149  and  priced  from 
$9.75  to  $60.00  without  accessories.  Add 
10%  to  all  prices  west  of  the  Rocky 
Mountains.  See  your  Crosley  dealer  or 
write  Department  63  for  catalogue  of 
complete  Crosley  line. 

B     E     T     T     E    R  COSTS        LESS 

THE  CROSLEY  RADIO  CORPORATION 

Cincinnati,  Ohio. 

Owning  and  operating    WLW,   first  remote    control 
Super  power  Broadcasting  station. 


An  Announcement 

of  Importance 

to  Every  American 

Radio  Fan! 

Turn  to  page  20  of  this 

issue  of 

RADIO 

AGE 


KARAS 


AUDIO  FREQUENCY 


&MONIK 


AMPLIFYING  TRANSFORMER 


For  over  30  years 

makers  of 

PRECISION 

Electrical  Apparatus. 


'/j 


Qbe  Wriumph  cfaWiasterfnecej 


—A  Marvel  of  Transformers  that  Brought  Real 
Musical  Quality  to  Radio  Reception 


/ 


The  Distinctive  Qualities  that 
Elevate  Karas  Harmonik  Trans- 
formers to  the  Highest  Pinnacle 
of  Success  in  the  Radio  World. 


JUST  one  year  ago  the  Karas  Harmonik  Audio 
Frequency  Transformer  took  the  radio 
world  by  storm. 

Nothing  like  it  had  ever  been  known  before. 
For  the  first  time,  scientific  study  had  been  de- 
voted to  perfecting  an  audio  transformer  for  the 
reception  of  broadcast  music.  The  problem  of 
amplifying  high,  low  and  medium  frequencies 
to  equal  degree  was  finally  solved.    Bass  notes 
were  poured  from  the  speaker  in  full  strength 
and  rich  tone  quality.   The  vital  harmonics  in 
rich  overtones,  formerly  lost, 
were  brought  out  in  their  full 
beauty  by  this  marvel  of  audio 
transformers. 

Music  critics,  who  had  always 
condemned  radio  music  as  false 
and  distorted,  approved  the  re- 
sults of  Karas  Harmonik  ampli- 
fication with  great  enthusiasm. 
Prominent  radio  engineers  sub- 
jected Karas  Harmoniks  to  ex- 
haustive laboratory  tests — and 
pronounced  it  a  technical 
masterpiece.  Technical  editors 
who  promoted  the  season's  most 
successful  hook-ups  specified 
Karas  Harmoniks  in  their  cir- 
cuits. The  triumph  of  the  Karas 
Harmonik  was  complete ! 

But,  for  all  of  this,  the  enjoyment  of  Karas  Harmonik 
amplification  was  too  greatly  confined  to  one  class  of 
radio  enthasiasts.  Home  set  builders  bought  Karas 
Harmoniks  by  the  tens  of  thousands.  They  were  free 
to  pick  and  choose.  They  were  most  exacting  in  their 
demands  for  the  newest  and  best  developments. 

It  was  the  owners  of  factory-built  sets  who  missed  the 


1.  Many  thousands  of  turns  of  wire 

2.  Low  ratio  of  turns 

3.  Extra  large  quantity  of  special 
formula  iron  in  core 

4.  Controlled  air  gap 

5.  No  core  saturation 

6.  Minimum  of  Reluctance 

7.  Least  Hysterisis  and  Eddy  Current 
Loss 

8.  Low  Distributed  Capacity 

9.  Scientifically  circular  _  shielding 
preventing  intercoupling  of  elec- 
trostatic and  electromagnetic 
fields 

10.  Very  High  Primary  Impedance 

11.  Extremely  High  Inductance 

12.  High  and  even 
Amplification 
of  all  Andio 
Frequencies. 


delightful  pleasure  of  real,  true  radio  music  in 
their  homes.  Set  manufacturers  were  prevented 
by  price  from  adopting  Karas  Harmoniks  for 
their  sets.  So  the  ready-made  set-buyer,  unless 
he  undertook  to  switch  transformers,  had  to 
do  without  Karas  Harmoniks. 

Today  there  are  in  use,  hundreds  of  thousandsof  sets — good 
sets — which  could  be  vastly  improved  in  musical  quality  by 
the  simple  operation  of  replacing  the  old  transformers  with 
Karas  Harmoniks.    Perhaps  you  own  one  of  these  sets.    It 
may  be  all  you  desire  from  the  standpoint  of  selectivity,  of 
range,  and  other  tuning  qualities.  But,  if  it  is  not  equipped 
with  Karas  Harmonik  Audio  Frequency 
Transformers,  you  are  NOT  getting 
nearly  the  musical  quality  you  can  just  as 
well  enjoy.  Are  you  going  to  be  content 
with  anything  short  of  the  best? 
You  can  install  Karas  Harmoniks  your- 
self. It's  a  short,  easy  job.  Or,  any  radio 
repair  man  can  do  it  for  you.    Make  up 
your  mind  to  do  it  now — at  once.  Get  a 
pair  of  Karas  Harmoniks  TODAY! 


In  large  cities,  most  good  dealers  carry  Kara* 
Harmoniks— and  in  many  small  towns.  If  your 
dealer  is  out  of  them,  order  direct  from  us. 
Send  no  money.    Just  use  the  coupon  below ! 

Karas  Electric  Co., 

4065  N.  Rockwell  St., 
Chicago,  111. 


If  you  send  cash 
^-  with  order,  we'll  send 
transformers  postpaid. 


*    Tested  and  Approved  by  RADIO  AGE    * 


64 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


Build  the  Set  That 
Holds  4  World's  Records 


The  receiver  that  brought  in  sta- 
tions 6,000  to  8,000  miles  distant 
with  loud  speaker  volume  night 
after  night. 

Holds  World's  Records  For 

(1)  Longest  distance  ever  received  on  a 
loop  aerial — 8,375  miles 

(2)  Most  consistent  reception  of  stations 
6,000  to  8,000  miles  distant— 117  pro- 
grams in  three  months. 

(3)  Brought   in   6  different  stations   in  2JJ 
hours — all  over  6,000  miles 

Full  sized  blue  prints  with  com- 
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make  exact  duplicate  of  this 
marvelous  receiver. 


PRICE  $5 


Story  of  development  and  proofs  of  records 
sent  on  receipt  of  stamped  and  addressed 
envelope. 

Scott  Radio  Laboratories 

35  S.  Dearborn  St.,  Chicago 

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$110,000  Super-Station   Plan- 
ned for  St.  Louis 

The  primary  plans  of  organization 
were  completed  recently  for  the  establish- 
ment in  St.  Louis  of  one  of  the  largest 
and  most  eleborate  radio  broadcasting 
stations  in  the  United  States.  The  pro- 
ject, which  is  being  undertaken  by  nine 
representative  business  organizations  of 
St.  Louis,  including  the  Globe-Democrat, 
involves  the  erection  of  a  $110,000  super- 
station,  which  is  expected  to  be  ready 
for  operation  shortly  before  Christmas. 
It  will  be  announced  as  St.  Louis'  Christ- 
mas gift  to  the  nation.  Contracts  for 
the  apparatus  have  been  placed  with  the 
Western  Electric  Company. 

It  is  proposed  that  this  mammoth 
stations,  operated  at  a  cost  of  approxi- 
mately $135,000  a  year,  wiU  typify  the 
"voice  of  St.  Louis,"  identifying  the  city 
with  superpower  and  super-programs 
of  exceptional  merit.  Application  will 
be  made  for  a  charter  for  a  corporation, 
membership  in  which  will  be  held  by  the 
following  original  organizers:  St.  Louis 
Globe-Democrat,  The  Merchants'  Ex- 
change of  St.  Louis,  The  Brown  Shoe 
Company,  Skouras  Brothers  Enter- 
prises, C.  F.  Blanke  Tea  and  Coffee 
Company,  Colin  B.  Kennedy  Corpora- 
tion, Wagner  Electric  Corporation,  St. 
Louis  Radio  Trade  Association  and 
George  Kilgen  &  Son,  Inc. 

To  Include  Sixteen  Firms 

The  plan  calls  for  a  total  member- 
ship of  sixteen  firms  and  several  other 
concerns,  besides  the  present  members, 
are  considering  the  plan  with  a  view  to 
joining  the  organization. 

The  Board  of  Trustees  of  the  organiza- 
tion is  composed  of  E.  Lansing  Ray, 
president  of  the  Globe-Democrat,  chairman; 
W.  A.  Layman,  president  of  the  Wagner 
Electric  Company,  and  C.  F.  Blanke, 
president  of  the  C.  F.  Blanke  Tea  and 
Coffee  Company. 

The  entire  enterprise  has  been  inspired 
by  the  civic  interest  among  the  organi- 
zers, who  expect  the  project  to  prove  an 
important  factor  in  fostering  the  develop- 
ment of  the  city  and  community. 

W.  Palmer  Clarkson,  president  of  the 
Chamber  of  Commerce,  has  been  pres- 
ent at  several  of  the  meetings,  which 
have  been  held  during  recent  weeks  to 
perfect  the  organization,  and  has  mani- 
fested enthusiasm  over  the  possibilities 
which  the  plan  offers  for  advertising  the 
city. 

"  Capital  of  49th  State  " 

The  programs,  which  will  take  rank 
with  the  outstanding  radio-casting  pro- 
grams of  the  world,  will  be  designated  as 
coming  from  "St.  Louis,  the  Capital  of 
the  49th  State."  and  while  the  call  letters 
have  not  yet  been  assigned,  it  is  probable 
that  their  arrangement  will  suggest 
"The  49th  State." 

Business  offices  have  already  been 
established  at  737  Frisco  Building,  under 
the  management  of  Thomas  P.  Convey, 
general  manager  of  the  St.  Louis  Radio 
Trades  Association.  A  committee,  com- 
posed of  Colin  B.  Kennedy,  Melville  B. 
Hall,  treasurer  Brown  &  Hall  Supply 
Company,  and  W.  A.  Layman,  president 
Wagner  Electric  Company,  will  select 
a  site  for  the  broadcasting  towers  and 
building,  which  will  be  located  about 
sixteen  miles  from  the  heart  of  the  city. 
This  committee  is  also  negotiating  for 
temporary  quarters  for  the  central  studio, 
where  the  programs  will  be  produced, 
pending  completion  of  the  new  Ambassa- 
dor Building.  Permanent  studios  will 
eventually  be  located  on  the  top  floor 
(Continued  on  page  65) 

*    Tested  and  Approved   by  RADIO  AGE    * 


Pat. 

April 
21,1915 


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RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


65 


of  that  building,  adjoining  the  miniature 
rehearsal  theater  of  the  Skouras  Bros', 
enterprises. 

Engineers  on  Way 

Engineers  are  now  on  the  way  to  St. 
Louis,  having  been  sent  by  the  Western 
Electric  Company  to  survey  the  ground 
here  and  supply  the  technical  informa- 
tion necessary  for  immediate  installation. 

The  reason  for  the  location  of  the  broad- 
casting towers  at  a  point  removed  from 
the  city,  according  to  members  of  the 
organization,  is  that  programs  trans- 
mitted from  such  a  station  will  offer  a 
minimum  of  interference  with  the  less 
powerful  broadcasting  from  other  St. 
Louis  stations. 

"The  radio  receiving  public  is  becom- 
ing more  and  more  discriminating," 
said  W.  A.  Butler,  manager  of  radio 
apparatus  sales  of  the  Western  Electric 
Company,  in  discussing  the  project. 
"Radio  enthusiasts  want  better  pro- 
grams and  better  broadcasting.  For  this 
reason,  our  company,  in  recommending 
the  apparatus  and  the  location  for  this 
super-station,  has  urged  the  selection  of 
an  outlying  site,  which  will  enable  listen- 
ers to  tune  out  selectively,  without, 
however,  monopolizing  the  air. 

Effective  Throughout  Nation 

"St.  Louis,  in  its  geographical  loca- 
tion, is  exceptionally  well  adapted  to  the 
establishment  of  a  super-station  like  the 
one  planned.  This  station,  with  its 
5000-watt  capacity,  will  be  ten  times  as 
powerful  as  any  within  'The  49th 
State.'  It  will  have  a  dominant  range 
throughout  'The  49th  State,'  and,  ac- 
cording to  the  experience  of  similar 
stations,  an  effective  range  throughout 
the  entire  nation." 

While  the  plans  for  the  programs  have 
not  yet  been  announced  in  detail,  mem- 
bers of  the  organization  pointed  recent- 
ly to  the  possibilities  offered  by  the 
grouping  of  a  newspaper,  a  producing 
company,  an  organ  manufacturer,  radio 
trade  organizations,  commercial  and 
manufacturing  firms  and  the  Merchants' 
Exchange.  They  indicated  that  the 
programs  will  be  widely  varied,  ranging 
from  news  announcements  and  enter- 
tainment features  of  unusual  nature  to 
market  quotations  which  will  enable 
farmers  and  stock  raiser  to  ship  and  sell 
their  products  most  advantageously. 
Value  to  Exchange 

The  Merchants'  Exchange,  it  was  dis- 
closed, was  inspired  to  join  in  this  pro- 
ject in  order  to  protect  business  within 
the  St.  Louis  trade  territory  against  the 
overtures  from  markets  in  other  cities, 
where  grain  exchanges  have,  for  some 
time,  been  broadcasting  market  quota- 
tions from  their  own  stations. 

"The  importance  of  the  radio,  as  it 
concerns  the  farmer,  has  been  increasingly- 
apparent,"  said  Woodson  K.  Woods,  pre- 
sident of  the  Merchants'  Exchange, 
recently.  "With  this  new  super-station 
we  hope  to  draw  stock  men  and  grain 
growers  closer  to  the  St.  Louis  market, 
through  our  ability  to  broadcast  the 
latest  market  quotations. 

"Broadcasting  St.  Louis  grain  market 
quotations  will  put  the  St.  Louis  market 
in  better  position  to  grow  grain  than  it 
has  occupied  for  many  years." 

New  X-L  Binding  Post 
Loose  connections  are  done  away  with 
in  the  new  "Push  Post,"  put  out  by  the 
X-L  Radio  Laboratories  of  2424  Lincoln 
Avenue  N,  Chicago,  makers  of  the  well 
known  X-L  Variodensers.  All  that  is 
necessary  is  to  push  the  post  down,  in- 
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#     Tested  and  Approved  by  RADIO  AGE     # 


66 


KDKA 

KDLR 

KDPM 

KDYL 

KDZB 

KDZI 

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RADIO  AGE /or  November,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


Westinghouse  Electric  &  Mfg.  Co East  Pittsburgh,  Pa.  309  ££VY 

Radio  Electric  Co Devils  Lake.  N.  D.  231  £EX?. 

Westinghouse  Electric  &  Mfg.  Co Cleveland,  Ohio  270  KFW A 

Newhouse  Hotel  Salt  Lake  City,  Utah  250  KFWB 

Frank  E   Sietert Bakersfield,  Cahf.  240  KFWC 

Electric  Supply  Co Wenatchee,  Wash.  360  KFWV 

Nebraska  Buick  Auto  Co..  13th  &  Que  Sts Lincoln,  Nebr.  341  ££x** 

McArthur  Bros.  Mercantile  Co Phoenix,  Ariz.  273  KFWD 

State  College  of  Washington Pullman,  Wash.  348  *>twu 

Western  Radio  Corporation Denver,  Colo.  278  •>£..,. 

University  of  Colorado Boulder.  Colo.  360  £FWI 

University  of  Idaho Moscow,  Idaho  230  KFWM 

Boise  High  School Boise,  Idaho  271  *>EW,2 

The  Radio  Den  VW.  B.  Ashford) Santa  Ana,  Calif.  280  5E3XTt 

F.  A.  Buttrey  &  Co Havre,  Mont.  360  KFWU 

W  K  Azbill  San  Diego.  Calif.  278  KFXC 

First  Presbyterian  Church Tacoma.  Wash.  250  KFXDT 

Kimball-Upson  Co Sacramento,  Calif.  283  KFXE 

Leese  Bros Everett.  Wash.  224  KFXF 

School  District  No.  One Trinidad,  Colorado  238  KFXH 

Bishop   N.   S.   Thomas Laramie,   Wyo.  270  KFXJ 

Nielson  Radio  Supply  Co Phoenix,  Ariz.  238  KFXM 

The  First  Congregational  Church Helena,  Mont.  248  KGB 

Frank  A.  Moore Walla  Walla.  Wash.  256  KGO 

Omaha  Central  High  School Omaha,  Nebr.  258  KGU 

St.  Michaels  Cathedral Boise,  Idaho  252  KGW 

University  of  Arizona Tucson,  Ariz.  368  KGY 

Oregon  Agricultural  College Corvallis,  Ore.  254  KHJ 

Magnolia  Petroleum  Co Beaumont.  Texas  315  KHQ 

First  Baptist  Church Shreveport,  La.  360  KJR 

South  Dakota  State  College Brookings.  S.  Dak.  360  KJS 

Harry  O.  Iverson Minneapolis,  Minn.  231  KLDS 

Meier  &  Frank  Co Portland.  Oreg.  248  KLS 

Augsbury  Seminary Minneapolis,  Minn.  261  KLX 

Winner  Radio  Corp Denver,  Colo.  254  KLZ 

J.  L.  Scroggin Oak.  Nebr.  268  KMA 

Bunker  Hill  &  Sullivan  Mining  and  Concentrating  Co Kellogg,  Idaho  233  KM  J 

First    Baptist    Church Moberly.    Mo.  260  KMO 

Graceland    College Lamoni,    Iowa  280  KNX 

Ileidhreder  Kadi..  Supply  Co Utica,  Neb.  224  KOA 

Louisiana  State  University Baton  Rouge,  La.  254  KOB 

Chickasha  Radio  &  Electric  Co Chickasha.  Okla.  248  KOIL 

Leland  Stanford  University Stanford  University,  Calif.  273  KOP 

Crary  Hardware  Co. Boone,  Iowa  226  KPO 

Western  State  College  of  Colorado Gunnison,  Colo.  252  KPPC 

Ambrose  A.  McCue Neah  Bay,  Wash.  261  KPRC 

Penn  College Oskaloosa,  Iowa  240  KQP 

E.  C.  Anthony,  Inc Los  Angeles,  Calif.  468  KQV 

Benson  Polytechnic  Institute Portland,  Oreg.  248  KQW 

North  Central  High  School Spokane,  Wash.  252  KRE 

First  Methodist.  ('Lurch Yakima,  Wash.  242  KSAC 

Alaska  Electric  Light  &  Power  Co Juneau,  Alaska  226  KSD 

Daily  Commonwealth Fond  du  Lac,  Wis.  273  KSL 

Marshall  Electrical  Co ' Marshalltown,  Iowa  248  KTAB 

R.B.Fegan  (Episcopal  Church) Junction  City,  Kansas  219  KTBR 

National  Radio  Manufacturing  Co Oklahoma  City.  Okla.  252  KTCL 

Liberty  Theatre  (E.  E.  Marsh) Astoria.  Oreg.  252  KTHS 

Hardsacg  Manufacturing  Co Ottumwa.Iowa  242  KTW 

University  of  North  Dakota Grand  Forks.  N.  Dak.  280  KUO 

Ashley  C.   Dixon  &  Son Portland,  Oreg.  258  KUOM 

Iowa  State  Teacher's  College Cedar  Falls.  Iowa  280  KUPR 

Tunwall    Radio    Co Fort   Dodge.    Iowa  246  KWG 

W.  E.  Branch Fort  Worth,  Texas  254  KWKC 

Colorado  State  Teachers  College Greeley,  Colo.  273  KWWG 

Conway  Radio  Laboratories  (Ben  H.  Woodruff) Conway,  Ark.  250  KYO 

The  University  of  Kansas Lawrence,  Kans.  275  K  YW 

Westinghouse  Electric  &  Manufacturing  Co Hastings,  Nebr.  288  KZM 

Paul  E.  Greenlaw Franklinton.  La.  234  WAAB 

Everett  M.Foster Cedar  Rapids,  la.  256  WAAC 

University  of  New  Mexico Albuquerque,  New  Mexico  254  WAAD 

Rio  Grande  Radio  Su  nply  House San  Benito,  Texas  236  WAAF 

Rev.  A.  T.  Frykman Rockford,  111.  229  WAAM 

George  Roy  Clough Galveston,  Texas  240  WAAW 

Atlantic  Automobile  Co Atlantic,  la.  273  WABA 

Christian  Churches Little   Rock.   Arl.  254  WABB 

University  of  Arkansas Fayetteville,  Ark.  299  WABC 

Morningside  College .Sioux  City,  Iowa  261  WABI 

M.  G.  Sateren Houghton.  Mich.  266  WABL 

Carleton   College Northfield,  Minn.  336  WABO 

Henry  Field  Seed  Co Shenandoah,  Iowa  266  WABQ 

Wooten's  Radio  Shop Coldwater.  Miss.  254  WABR 

L.  A.  Drake  Battery  and  Radio  Supply  Shop Santa  Rosa,  Calif.  234  WABW 

Rhodes  Department  Store Seattle.  Wash.  454  WABX 

Leslie  M.Schafbush Marengo,  Iowa  234  WABY 

Eehophone  Radio  Shop Long  Beach,  Calif.  234  WABZ 

Latter  Day  Sain  ts'  University Salt  Lake  City,  Utah  261  WADC 

Rohrer  Elec.  Co Marshfield,  Ore.  240  WAFD 

David  City  Tire  &ElectricCo David  City.  Nebraska  226  WAHG 

College  Hill  Radio  Club Wichita.  Kansas  231  WAPI 

Board  of  Education, Technical  High  School Omaha,  Nebraska  248  WAMD 

Beacon  Radio  Service St.  Paul,  Minn.  226  WBAA 

Garretson  and  Dennis.. Los  Angeles,  Calif.  238  WBAC 

C.  C.  Baxter Dublin,  Texas  242  WBAH 

The  New  Furniture  Co Greenville.  Texas  242  WEAK 

Los  Angeles  County  Forestry  Dept j Los  Angeles,  Calif.  231  WBAO 

Cape  &  Johnson Salt  Lake  City,  Utah  286  WBAP 

St.  Johns  M.  E.  Church Carterville.  Mo.  268  WBAV 

Symons   Investment  Co Spokane,   Wash.  283  WBAX 

The   Principia St.    Louis.    Mo..  264  WBA Y 

The  Searchlight  Publishing  Co Fort  Worth,  Texas  221  WBBG 

Kidd  Brothers  Radio  Shop Taft,  Calif.  258  WBBL 

Radio  Service  Co Burlingame,  Calif.  231  WBBM 

G.  S.  Carson,  Jr.  . Iowa  City,  la.  284  WBBN 

Texas  National  Guard Dennison,  Texas  252  WBBP 

W.  Riker Holy  City,  Calif.  253  WBBR 

C.  F.  Knierira North  Bend.  Wash.  248  WBBS 

Taft  Products  Co Hollywood,  Calif.  240  WBBU 

City  of  Paris  Dry  Goods  Co San  Francisco.  Calif.  268  WBBX 

James  P.  Boland,  1st  Lt.,  U.S.  Army Ft.  Sill,  Okla.  242  WBB  Y 

Etherical  Radio  Co Bristow,  Okla.  394  WBBZ 

United  Churches  of  Olympia Olympia,  Wash.  220  WBCN 

J.  Gordon  Klemgard PuUman.  Wash.  217  WBDC 

The  Electric  Shop Hartington,  Neb.  222  WBES 

Angelus  Temple Los  Angeles,  Calif.  272  WBGA 

The  Van  Blaricon  Co Helena,  Mont.  261  WBOQ 

Hopper  Plumbing  and  He  Ldng  Co Breckenridge,  Minn.  242  WBR 

Thomas  Goggan  &  Bros.  Music  Co Galveston,  Texas  258  WBRC 

W.  D.  Pyle Colorado  Springs.  Colo.  242  WBRE 

Concordia  Seminary St.   Louis,  Mo.  549  WBS 

Fitz.-uminon.s  Gener.-d  Hospital Denver,  Colo.  234  WBT 

Julius  Bmnton  and  Sons  Co San  Francisco.  Calif.  234  WBZ 

H.  W.  Peery  and  C.  Redfield Ogden,  Utah  224  WBZA 

Louis  L.  Sherman Oakland.  Calif.  233  WCAD 

University  of  Utah Salt  Lake  City,  Utah  271  WCAE 

Colburn  Radio  Labs San  Leandro,  Calif.  231  WCAH 

Y.  M.  C.  A Virginia,  Minn.  244  WCAJ 

McWhinnie  Electric  Co dan  Pedro,  CaUf.  202  WCAL 

Film  Corporation  of  America St.  Louis,  Mo.  245  WCAO 

Clarence  B.Juneau Hollywood.  Calif.  208  WCAP 

First  M.E  Church Independence.  Kansas  236  WCAR 

Whan  Radio  Shop  (Herbert  Whan) Manhattan.  Kansas  218  WCAS 

Headquarters  Troop,  56th    Cavalry Houston .  Texas  248  WCAT 

Carl  E.    Bagley Welcome.  Minn.  227  WCAU 

F.  M.    Henry Ki-dcsville,    Mo.  226  WCAX 

Moorlight  Ranch Roure  6,  Denver,  Colo.  246  WCAZ 

Cape  Girardeau  Battery  Station.  . . . '. Cape  Girardeau,  Mo.  224  WCBA 


Radio  Supply  Co Albuquerque,  N.  M.  250 

Glad  Tidings  Tabernacle San  Francisco.  Calif.  234 

Browning  Bros.  Co Ogden,  Utah  214 

Warner  Bros Hollywood,  Calif.  252 

L.  E,  Wall Upland.  Calif.  211 

Wilbur   Jerman 385    68th  St.  S..  Portland,    Ore.  212 

Bertram  O.  Heller Big  Bear  Lake,  Calif.  203 

Arkansas  Light  &  Power  Co Arkadelphia.  Arkansas  266 

St.  Louis  Truth  Center St.  Louis,  Mo.  214 

F.  Wellington  Morse,  Jr Chico,  Calif.  254 

Radio  Entertainments,   Inc South  San  Francisco.  Calif.  220 

Oakland  Educational  Society Oakland,  Calif.  224 

Lawrence  Mott Avalon,  Calif.  211 

Rio  Grande  Radio  Supply  House Brownsville,  Texas  214 

Louisiana    College Pineville.    La.  238 

Santa   Maria   Valley   Railroad  Co Santa   Maria,  Calif.  210 

L.    H.    Strong Logan,  Utah  205 

Electrical  Research  &  Mfg.  Co Waterloo,  Iowa  236 

Pike's    Peak  Broadcasting    Co Colorado   Springs,   Colo.  250 

Bledsoe  Radio  Company El  Paso,  Texas  242 

States  Radio  Distributors,  Inc.  (Portable  station) Colorado  216 


Neches  Electric  Co Beaum. 

Tacoma  Daily  Ledger Tacoma,  Wash. 

General  Electric  Co Oakland,  Calif. 

Marion    A.    Mulrony Honolulu,    Hawaii,    Waikiki   Beach 

Portland  Morning  Oregonian Portland,  Oreg. 

St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy,  Wash. 

Times-Mirror  Co Los  Angeles,  Calif. 

Louis   Wasmer Seattle,  Wash. 

Northwest  Radio  Service  Co Seattle,  Wash. 

Bible  Institute  of  Los  Angeles,  Inc Los  Angeles,  Calif. 

Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints,  Independence,  Mo. 

Warner  Brothers  Radio  Supplies  Co Oakland,  Calif. 

Tribune  Publishing  Co Oakland,  Calif. 

Reynolds  Radio  Co Denver,  Colo. 

Shenandoah , Iowa 

San  Joaquin  Light  &  Power  Corp Fresno,  Calif.     243 

Love  Electric  Co -. Tacoma.  Wash.     250 

Los  Angeles  Evening  Express Los  Angeles,  Calif.     337 

General  Electric  Co Denver.  Colo.     323 

New  Mexico  College  of  Agriculture  &  Mechanic  Arts,  State  College,  N.  Mex.     348 

Monarch  Manufacturing  Co Council  Bluffs,  Iowa     278 

Detroit  Police   Department Detroit,  Mich.     286 

Hale  Bros San  Francisco,  Calif.     428 

Pasadena  Presbyterian  Church Pasadena,  Calif.     229 

Post-Dispatch Houston,   Texas 


227 
252 
361 
370 
491 
253 
405 
273 
384 
293 
441 
242 
508 
283 


Apple  City,  Radio  Club Hood  River.  Oregon  270 

Doubleday-Hill   Electric   Co Pittsbugh,  Pa.  270 

Charles  D.  Herrold T San  Jose,  Calif.  226 

C.  Battery  &  Electric  Co Berkeley,  Calif.  275 

State  Agricultural  College Manhattan,  Kans.  341 

Post  Dispatch  (Pulitzer  Pub.  Co.) St.  Louis,  Mo.  545 

Radio  Service  Corp.  of  Utah Salt  Lake  City,  Utah  299 

Tenth  Ave.  Baptist  Church Oakland,  Calif.  216 

Brown's  Radio  Shop Portland.  Oregon  263 

American  Radio  Telephone  Co.,  Inc. Seattle,  Wash.  306 

New  Arlington  Hotel  Co Hot  Springs.  Ark.  375 

First  Presbyterian  Church Seattle,  Wash.  455 

Examiner  Printing  Co San  Francisco,  Calif.  246 

State  University  of  Montana Missoula,  Montana  244 

Union   Pacific   Railroad  Co Omaha,  Neb.  270 

Portable  Wireless  Telephone  Co Stockton,  Calif.  248 

Wilson  Duncan  Studios Kansas  City,  Mo.  236 

City  of  Brownsville Brownsville,  Texas  278 

Electric   Shop Honolulu,  Hawaii  270 

Westinghouse  Electric  &  Mfg.  Co Chicago,  111.  535 

Preson   D.  Allen Oakland,  Calif.  242 

Valdemar  Jensen New  Orleans,  La.  263 

Tulane  University New  Orleans,  La.  275 

Ohio  Mechanics  Institute Cincinnati,  Ohio  248 

Chicago    Daily   Drovers   Journal ; Chicago,    111.  286 

I.  R.  Nelson  Co Newark,  N.  J.  263 

Omaha  Grain  Exchange Omaha,  Nebr.  285 

Lake  Forest  University Lake  Forest,  III.  227 

Harrisburg  Sporting  Goods  Co Harrisburg.  Pa.  266 

Asheville  Battery  Co.,  Inc Asheville.  N.  C.  254 

Bangor   Railway  &  Electric  Co Bangor.  Me.  240 

Connecticut    Agricultural   College Sorrs,   Conn.  283 

Lake  Avenue  Baptist  Church Rochester,  N.  Y.  283 

Haverford  College,   Radio  Club Haverford.  Pa.  261 

Scott  High  School,  N.  W.  B.  Foley Toledo,  Ohio  270 

College  of  Wooster Wooster,  Ohio  234 

Henry  B.Joy Mt.  Clemens,  Mich.  270 

John  Magaldi,  Jr Philadelphia,  Pa.  242 

Coliseum  Place  Baptist  Church New  Orleans.  La.  263 

Allen  T.  Simmons   (Allen  Theatre) Arkon,  Ohio  258 

Albert  B.  Parfet  Co Port  Huron,  Mich.  233 

A.  H.  Grebe  &  Co Richmond  Hill,  N.  Y.  315 

Alabama  Polytechnic   Institute Auhurn,  Ala.  248 

Hubbard  &  Co Minneapolis.  Minn.  244 

Purdue  University W.  Lafayette,  Ind.  283 

Clemson  Agric.  College Clemson  College,  S.  C.  331 

The  Dayton  Co Minneapolis,  Minn.  417 

Pennsylvania  State  Police Harrisburg,  Pa.  275 

James   Miliikan  University , Decautur,  111.  360 

Wortham-Carter  Publishing  (Star  Telegram) Fort  Worth,  Texas  476 

Emer  &  Hopkins  Co Columbus,  Ohio  292 

John  H.  Stenger,  Jr Wilkes-Barre,  Pa.  254 

Western  Electric  Co New  York,  N.  Y.  492 

Irving  Vermilya Mattapoisett,  Mass.  248 

Grace  Covenant  Presbyterian  Church Richmond,  Va.  253 

Atlass  Investment  Co Chicago,  111.  226 

Blake,  A.  B _ Wilmington,  N.  C.  275 

Petoskey  High  School Petoskey,  Mich.  246 

People's  Pulpit  Assoc Rossville.  N.  Y.  273 

First  Baptist  Church New  Orleans,  La.  252 

Jenks  Motor  Sales  Co Monmouth,  111.  224 

Ruffner  Junior  High  School Norfolk,  Va.  222 

Washington   Light  Infantry  Co.  *'B"  118th  Inf Charleston,  S.  C.  268 

C.  L.    Carrel,    (portable) Chicago,   111.  216 

Foster    &    McDoland Chicago.    111.  266 

Baxter  Laundry  Co Grand  Rapids.  Mich  256 

Bliss  Electrical  School Takoma  Park,  Md.  222 

Jones  Elec.  &  Radio  Mfg.  Co Baltimore,  Md.  254 

A.  H.  Grebe  &  Co.,  Inc Richmond  Hill.  N.  Y.  236 

Pennsylvania  State  Police Butler,  Pa.  286 

Bell  Radio  Corporation Birmingham,  Ala.  248 

Baltimore  Radio  Exchange Wilkes-Barre,  Pa.  231 

D.  W.  May,  Inc Newark,  N.  J.  252 

Southern  Radio  Corp Charlotte,  N.  C.  275 

Westinghouse  Electric  &  Mfg.  Co Springfield,  Mass.  333 

Westinghouse  Electric  &  Mfg.  Co Hotel  Brunswick,  Boston,  Mass.  242 

St.   Lawrence  University Canton,   N.  Y.  280 

Kaufmann  &  Baer  Co.  and  The  Pittsburgh  Press Pittsburgh,  Pa.  461 

Entrekin  Electric  Co Columbus.  Ohio  286 

Nebraska  Wesleyan  University University  Place, Nebr.  283 

St.  Olaf  College Northfield, Minn.  336 

Sanders  &  Stayman  Co Baltimore,  Md.  275 

Chesapeake  &  Potomac  Telephone  Co Washington,  D.  C.  468 

Alamo  Radio  Electric  Co San  Antonio,  Texas  263 

W.  H.Dunwoody  Industrial  Institute Minneapolis.  Minn.  280 

State  College  of  Mines Rapid  City,  S.  Dak.  240 

Durham  &  Co Philadelphia,  Pa.  278 

University  of  Vermont Burlington,  Vt.  250 

Carthage    College Carthage.    IU;  "24*6 

Charles  W.  Heibachm Allentown,  Pa.  280 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


67 


Broadcasters  Elect  Officers 

The  Annual  Convention  of  the  Na- 
tional Association  of  Broadcasters  was 
held  at  the  Commodore  Hotel,  New  York 
City,  on  September  16th  and  17th,  1925. 

New  officers  were  elected  as  follows: 
Officers 

President,  WOC,  Frank  W.  Elliot,  Davenport, 

Vice-President,  WHO,  Wm.  H.  Heinz,  Des 
Moines,  Iowa.  ' 

Vice-President,  WLW,  Powel  Crosley,  Jr., 
Cincinnati,  O.  '        " 

Secretary,  KFI,  A.  F.  Kales,  Los  Angeles,  Cal. 

Treasurer,  WNAC,  John  Shepard,  III,  Boston, 

Executive  Chairman,  Paul  B.  Klugh,  New  York 
City.  „ 

Directors 

Regional  Chairmen 

For  New  England,  WTIC,  W.  G.  Cowles,  Hart- 
ford, Conn. 

For  Atlantic — WAHG,  Alfred  H.  Grebe,  New 
York  City. 

For  Great  Lakes,  WJR,  E.  H.  Jewett,  Pontiac, 
Mich.  . 

For  Atlantic,  WHO,  George  Kuhns,  Des  Moines, 
Iowa.  _     .      .  , 

For  Pacific — KFI,  Earle  C.  Anthony,  Los  Ange- 
les, Cal. 

KFAB — Charles  Stuart,  Lincoln,  Neb. 

KFIX — Arthur  B.  Church,  Independence,   Mo. 

KFWA — Robert  Nevins,  Ogden,  Utah. 
KLX — J.  R.  Knowland,  Oakland,  Cal. 

KPO — R.  B.  Hale,  San  Francisco,  Cal. 

WCCO — Prof.  C.  M.  Jansky,  Jr.,  Minneapolis- 
St.    Paul,    Minn. 

WEAF — W.  E.  Harkness,  New  York  City. 

WFBG — Walter  S.  Greevy,  Altoona,  Pa. 

WGHP — George  Harrison  Phelps,  Detroit, 
Mich. 

WGN — George  Morris,  Chicago,  111. 

WGR — W.  E.  Kideney,  Buffalo,  N.  Y. 

WHT — H.  H.  Bligh,  Chicago,  111. 

WIP — Richard  Gimbel,  Pniladelphia,  Pa. 

WJAZ — E.     F.     McDonald,     Jr.,     Chicago,     111. 

WLS — Edgar  Bill,  Chicago,  111. 

WTAM — S.  E.  Baldwin,  Cleveland,  Ohio. 

The  Membership  Committee  reported 
favorably  upon  a  large  number  of  appli- 
cations, principal  among  which  was 
Station  WEAF,  The  American  Tel.  & 
Tel.  Co.  of  New  York  City.  All  were 
unanimously     elected     to     membership. 

Among  the  important  matters  dis- 
cussed was  the  troublesome  copyright 
matter.  Ever  since  broadcasting  was 
started  there  has  been  a  conflict  between 
the  publishers  of  music  and  broadcasting 
stations  over  the  public  performance  of 
music.  At  first  broadcasters  took  the 
position  that  the  copyright  law  did  not 
contemplate,  and  therefore  did  not  cover 
broadcasting  of  music,  for  the  reason 
that  such  broadcasting  is  in  the  nature 
of  a  public  service,  and  is  without  any 
means  of  having  direct  pecuniary  return 
from  the  listeners.  For  various  reasons 
the  position  of  broadcasters  is  now 
changed  to  one  desiring  to  see  that  the 
writers  of  songs  themselves,  as  well  as 
their  assignees,  shall  be  paid  a  fair  sum. 
Many  plans  have  been  discussed,  finally 
resolving  in  adopting  at  this  convention, 
the  doctrine  of  extending  the  present 
paragraph  of  the  copyright  law  relating 
to  mechanical  reproduction  to  _  cover 
broadcasting.  Unanimous  adoption  of 
the  following  resolution  expresses  the 
basis  upon  which  broadcasting  stations 
propose  to  deal  with  this  subject: — 

"WHEREAS,  there  are  here  assembled  at 
the  Annual  Convention  of  the  National  Asso- 
ciation of  Broadcasters  a  considerable  number 
of   representative    broadcasting   stations, 

IT  IS  RESOLVED  that  the  following  plan 
be  presented  to  all  broadcasting  stations  for 
their  approval  or  disapproval,  and  in  the 
event  of  their  approval, 

THEN  BE  IT  FURTHER  RESOLVED 
that  the  following  plan  go  into  effect;  that  the 
principle  involved  in  the  reproduction  of 
music  by  mechanical  means  now  embodied  in 
the  present  copyright  law  be  extended  to  the 
reproduction  of  music  by  radio." 

\nother  matter  of  importance  was  the  ques- 
(Turn  to  page  69) 


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RADIO  AGE  for  November,  1925 

University  of  Michigan Ann  Arbor.  Mich. 

Wilbur    C.     VoUva -. . Z'on,     IU. 

Uhalt  Radio  Co New  Orleans,  La. 

Paul  J.  Miller. .  . , Pittsburgh,  Pa. 

Howard  S.  Williams  (Portable) Pascagoula,  Miss. 

University  of  Miss Oxford,    Miss. 

Charles  Swarz : Baltimore,  Md. 

James  P.  Boland Ft.  Beoj.  Harrison.  Ind. 

First  Baptist  Church Nashville,  Tenn. 

C.  H.  Messter Providence.  R.  I. 

Clark  University,  Collegiate  Dept Worcester,  Mass. 

Arnold   Wireless  Supply  Co Arnold.    Pa. 

Radio  Shop  of  Newark  (Herman  Lubinsky) Newark,  N.  J. 

Washburn-Crosby  Co Twin  Cities,  Mmn. 

C.  E.  Whitmore Camp  Lake.  Wise. 

H.    M.    Couch '■'■ Joliet.    IU. 

Henry  P.  Rines Portland,  Maine 

C.  T.  Scherer  Co. Worcester,  Mass. 

Free  Press  and  Jewett  Radio  &  Phonograph  Co Detroit,  Mich. 

Dad's    Auto    Accessories,    Inc. .  .  . Nashville,  Tenn. 

Tampa    Daily   Times Tampa,    Fla. 

Kansas  City  Star Kansas  City.  Mo. 

J.  Laurence  Martin Amarillo.  Texas 

Lit    Brothers Philadelphia,    Pa. 

Radio  Equipment  Corp Fargo,  N.  Dak. 

Fred  Ray Columbus.  Ga. 

A.  H.  Waite  &  Co.,  Inc Taunton,  Mass. 

Kirk,  Johnson  &  Co •  .Lancaster,  Pa. 

Herman     Edwin    Burns Martinsburg,     W.    Va. 

Gilham-Schoen    Elec.    Co Atlanta.   Ga. 

Richardson  Wayland  Electrio  Corp Roanoke.  Va. 

M.  F.  Broz Cleveland.  Ohio 

Wis.  Dept.  of  Markets Stevens  Point,  Wis. 

Electric  Light  &  Power  Co Bangor,  Me. 

Rollins  College,  Inc Winter  Park,  Fla. 

Morton  Radio  Supply  Co Salem,  N.J. 

Tremont  Temple  Baptist  Church Boston.  Mass. 

The  Strand  Theatre Fort  Wayne.  Ind. 

Otto  Baur New  York.  N.  Y. 

North  Shore  Congregational  Church Chicago.  111. 

Boy  Scouts.  City  Hall Kingstown.  N.  Y. 

Dartmouth  College Hanover.  N.  H. 

Chattanooga  Radio  Co.,  Inc . Chattanooga,  Tenn. 

Dutee  Wilcox  Flint,  Inc Cranston,  R.  I. 

J.    L.  Bush Tuscola.    IU. 

F.  D.    Fallain Flint,    Mich. 

American  Telephone  &  Telegraph  Co New  York,  N.  Y. 

Hotel   Lassen Wichita,  Kans. 

Cornell    University Ithaca,    N.     Y. 

University  of  South  Dakota Vermilion.  S.  Dak 

Borough  of  North  Plainfield  (W.  Gibson  Buttfield) .  .North  Plainfield,  N.  J. 

Shepard  Co Providence.  R.  I. 

Ohio  State  University Columbus,  Ohio 

Goodyear  Tire  and  Rubber  Co Cleveland.  Ohio 

Davidson  Bros.  Co Sioux  City,  Iowa 

Iris  Theatre  ( WiU  Horowitz,  Jr.) Houston.  Texas 

Benwood  Co St.   Louis,    Mo. 

Electrio     Shop Highland      Park,      N.      J. 

Walter   Cecil   Bridges Superior,    Wis. 

Electrical  Equipment  and  Service  Co Anderson,  Ind. 

Roy  W.  Walker Cambridge.  Ohio 

Edgewater  Beach  Hotel,  Chicago  Evening  Post  Station Chicago,  IU. 

Third  Avenue  Railway  Co New  York,  N.  Y. 

Grand  Rapids  Radio  Co Grand  Rapids.  Mich. 

Radio  Corporation  of  America Portable 

E.  B.  Pedicord New  Orleans,  La. 

The  Dayton  Coop.  Industrial  High  School Dayton,  Ohio 

Beloit      College Beloit.      Wis. 

The  Edison  Electric  Illuminating  Co Boston,  Mass. 

Robert  E.   Hughes , Evanston.    IU. 

'.• Barrien    Springs,     Mich. 

Ail-American  Radio  Corporation Chicago,  Illinois 

St.  Louis  University St.  Louis,  Mo. 

DaUas   News   &   Dallas   Journal Dallas,   Tex. 

Times  Publishing  Co St.  Cloud.  Minn. 

University  of  Nebraska.  Department  of  Electrical  Engineering.  Lincoln,  Nebr. 

First  Baptist  Church .  KnoxviUe.  Tenn. 

Gethsemane  Baptist  Church Philadelphia.  Pa. 

Van  De  Walle  Music  and  Radio  Co Seymour.  Ind. 

The  Wm.  F.  Cable  Co Altoona.  Pa. 

Concourse  Radio  Corporation New  York,  N.  Y. 

St.  John's  University CollegeviUe,  Minn. 

Wynne  Radio  Co.  . Raleigh.  N.  C. 

Fifth  Inf.  Md.  Nat'l  Guard.  5th  Reg.  Armory Baltimore,  Md. 

Ainsworth-Gates  Radio  Co Cincinnati,  Ohio 

Knox    College Galesburg,    111. 

Strawbridge  and  Clothier Philadelphia,  Pa. 

Francis   K.  Brideman Chicago.   IU. 

Robert  Morrisson  Lacey Brooklyn,  New  York 

G.  Pearson  Ward Springfield.  Mo. 

Earl   WilUam   Lewis Moberly,   Mo. 

Lancaster  Electrio  Supply  &  Construction  Co Lancaster,  Pa. 

Youree  Hotel Shreveport,  La. 

South  Bend  Tribune South  Bend.  Ind. 

Harry  H.  Carman,  217  Bedell  St Freeport,  N.  Y. 

First  Baptist  Church Memphis,  Tenn. 

Fink  Furniture  Co Evansville.  Ind. 

Brietenbach's   Radio  Shop Thrifton.   Va. 

Frank  S.  Megargee , Scranton,  Pa. 

Lawrence  CampbeU Johnstown,   Pa. 

Thedore  N.  Saaty Providence.  R.  I. 

Elyria  Radio  Asso.  (Albert  H.  Ernst) Elyria.  Ohio 

Stout  Institute Menominee,  Wis. 

Marshfield  Broadcasting  Assn Marshfield,  Wis. 

GimciBrothers \ New  York.  N.  Y. 

Furman  University GrcenviUe.  S.  C. 

Florida  Cities  Finance  Co Fulford  By-Tbe-Sea,  Florida 

University   of    Maine Orono.    Mo. 

Coyne  Electrical  School Oak  Park.  111. 

American  R.  &  R.  Co Medford  Hillside,  Mass. 

A.  H.  Grebe  &  Co..  Inc.,  Portable Richmond  Hill.  N.  Y. 

The  Tribune Chicago,  111. 

Federal  T.  and  T.  Co Buffalo,  N.  Y. 

General  Elec.  Co.  .  .    . Schenectady,  N.Y. 

University  of  Wisconsin Madison ,  Wis. 

Marquette  University  and  Milwaukee  Journal. . , Milwaukee.  Wis. 

University  of  Cincinnati Cincinnati,  Ohio 

Hafer  Supply  Co Joplin,  Mo. 

UniversityofRochester  (Eastman  School  of  Music) Rochester,  N.Y. 

H.  Alvin  Simmons.  200  Flatbush  Ave Brooklyn.  N.  Y. 

Seaside  House Atlantic  City.  N.  J. 

Courier-Journal  &  Louisville  Times Louisville.  Ky. 

Dr.  George  W.  Young Minneapolis,  Minn. 

Wilmington  Electrical  Specialty  Co Wilmington,  Del. 

Rensselaer  Polytechnic  Institute Troy,  N.  Y. 

Sweeney  School  Co Kansas  City.  Mo. 

C.  C.  Shaffer OU  City,  Pa. 

Hobel's  Store Stevens  Point.  Wis. 

Rev.  E.  P.  Graham Canton,  Ohio 

Chas.  W.   Howard BeUfontaine,  Ohio 

Beardsley  Specialty  Company Rock  Island,  lUinois 

John  S.  Skane Harrisburg.  Pa. 

Culver  Military  Academy Culver,  Ind. 

Lauer  Auto  Co Ft.  Wayne.  Ind. 

Franklin  St.  Garage.  Inc Ellsworth.  Me. 

James  H.Slusser Logansport.  Ind. 

C.  L.  Carroll.  Portable  Station Chicago.  111. 

First  Ave.  Methodist  Church St.  Petersburg.  Florida 

Johnstown    Automobile    Co Johnstown.    Pennsylvania 

St.  John's  M.E.  Church  South Memphis  Tenn. 

Scientific  Electric  &  Mfg.  Co.,  300-1  Vine  St Cincinnati,  Ohio 


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315 
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278 
252 
250 
261 
236 
370 
319 
379 
535 
280 
222 
283 
278 
240 
275 
399 
231 
360 
385 
365 
250 
240 
245 
222 
222 
231 
222 
234 
231 
220 
233 
258 
256 
233 
216 


WHBU  Riviera  Theatre  and  Bing's  Clothing.- Anderson,  Ind. 

WHB W  D.  R.  Kienzle Philadelphia,  Pa. 

WHBY  St.  Norbert's  CoUege West  De  Pore,  Wis. 

WHEC  Hickson  Electric  Co..  Inc Rochester,  N.Y. 

WHK  Radiovox  Company Cleveland.  Ohio 

WHN  George  Schubert New  York,  N.  Y. 

WHO  Bankers'  Life  Co Des  Moines,  la. 

WHT  Wrigley  Building.  Chicago Deerfield.  IU. 

WI  AD  Howard  R.  Miller Philadelphia  Pa. 

WIAO  Chronicle    Publishing    Co Marion,   Ind. 

WIAS  Home  Electric  Co Burlington,  Iowa 

WIBA  The  Capital-Times  Studio Madison,  Wis. 

WIBC  L.  M.  Tate  Post,  No.  29,  Veterans  of  Foreign  Wars ...  St.  Petersburg,  Florida 

WIBD  X-L   Radio  Service Joliet.  Illinois 

WIBG  St.  Paul's  Protestant  Episcopal  Church Elkins  Park,  Pa. 

WIBO  Nelson     Brothers Chicago,     IU. 

WIBH  Elite-Radio  Stores New  Bedford.  Mass. 

WIBI  Frederick  B.  Zitteli.  Jr Flushing,  N.  Y. 

WIBJ  C.  L.  Carrell  (Portable) Chicago.  IU. 

WIBK  University    of    Toledo Toledo.    Ohio 

WIBP  First  Presbyterian  Church Meridian,  Miss. 

WIBQ  F.    M.    Schmidt Farina.    IU. 

WIBR  Thurman  A.  Owings Werton.  W.  Va. 

WIBS  New  Jersey  Nat'l  Guard  Hdqs.  Co Elizabeth.  N.  J. 

WIBT  Orlando  Edgar  MiUer  (Portable  Station) New  York.  N.  Y. 

WIBU  The  Electric  Farm Poynette,  Wis. 

WIBW  Dr.  L.  L.  DiU Logansport,  Ind. 

WIBX  Grid-Leak  Inc Utica,  N.  Y.. 

WIBZ  Powell  Electrio  Company Montgomery,  Ala. 

WIL  Continental  Electric  Supply  Co Washington,  D.  C. 

WIP  Gimbel  Bros PhUadelphia.  Pa. 

WJAB  American  Electrio  Co Lincoln,  Nebr. 

WJAD  Jackson's  Radio  Engineering  Laboratories Waco,  Texas 

WJAG  Norfolk  Daily  News Norfolk,  Nebr. 

WJ AK  Clifford  L.  White Greentown,  Iowa 

WJAM  D.  M.  Perham Cedar  Rapids,  Iowa 

WJ  AR  The  Outlet  Co.  (J.  Samuels  &  Bro.) Providence.  R.I. 

WJAS  Pittsburgh  Radio  Supply  House Pittsburgh,  Pa. 

WJ  AZ  Zenith  Radio  Co Mt.  Prospect,  IU. 

WJBA  D.    H.    Lentz,   Jr Joliet,   IU. 

WJBB  L.  W.  McClurg St.  Petersburg, Fla. 

WJBC  Hummer    Furniture    Co LaSalle,    111. 

WJBD  Ashland  Broadcasting  Committee Ashland,  Wis. 

WJBI  Roberts.  Johnson Red  Bank,  New  Jersey 

WJBL  Wm.  Gushard  Dry  Goods  Co Decatur,  IU. 

WJD  Denison  University Granville.  Ohio 

WJJD  Supreme  Lodge,  Loyal  Order  of  Moose Mooseheart,  IU. 

WCX    I  Jewett  Radio  &  Phonograph  Co.  and  Detroit  Free  Press  . .  .  -Pontiac.  Mich. 

WJY  Radio  Corp.  of  America. New  York,  N.Y. 

WJZ  Radio  Corp.  of  America New  York.  N.Y. 

WK  AA  H.  F.  Paar Cedar  Rapids,  Iowa 

WKAD  Chas.  Looff  (Crescent  Park) East  Providence,  R.  I. 

WKAF  WKAF  BroadcastingCo Milwaukee,  Wis. 

WKA  Q  Radio  Corp.  of  Porto  Rico San  Juan,  P.  R. 

WKAR  Michigan  Agriculture  CoUege East  Lansing,  Mich. 

WKAV  Laconia  Radio  Club Laconia,  N.  H. 

WKBE  K.  &  B.  Electric  Co Webster,  Massachusetts 

WKBF  Dutee  Wilcox  Flint CranBten.  Rhode  Island 

WKBG  C.  L.  Carrel,  Portable Chicago.  HI. 

WKBK  Miss  Shirley  Katz New  York,  N.  Y. 

WKY  Wky  Radio  Shop Oklahoma  City,  Okla. 

WLAG  Cutting  cc  Washington  Radio  Corp Minneapolis,  Minn. 

WLAL  First  Christian  Church TuLsa.  Okla. 

WLAP  Wm.  V.  Jordan Louisville.  Ky. 

WLAQ  Arthur  E.  Shilling Kalamazoo.  Mich. 

WLAX  Putnam  Electrio  Co Greencastle,  Ind. 

WLIB  Liberty  Magazine Elgin,  111. 

WLB  University  of  Minnesota Minneapolis,  Minn. 

WLBL  Wisconsin  State  Dept.  of  Markets Stevens  Point,  Wis. 

WLS  Sears,  Roebuck  &  Co Chicago.  111. 

WLTS  Lane  Technical  High  School Chicago,  IU. 

WLW  Crosley  Mfg.  Co Cincinnati,  Ohio 

WLWL  Missionary  Society  of  St.  Paul  the  Apostle New  York,  N.Y. 

WMAC  J.  Edw.  Page  (Olive  B.  Meredith) Casenovia  -N.Y. 

WMAF  Round  Hills  Radio  Corp Dartmouth.  Mass. 

WM  AK.  Norton   Laboratories Lockport,   N.   Y. 

WMAL  Trenton  Hardware  Co Trenton,  N.  J. 

WMAN  First  Baptish  Church Columbus.  Ohio 

WMAO  Chicago   Daily  News Chicago,  IU. 

WMAY  Kingshighway  Presbyterian  Church St.  Louis,  Mo. 

WMAZ  Mercer    University Macon.    Ga. 

WMBB  Trianon    BaU    Room Chicago,   IU. 

WMBF  Miami  Beach  Hotel Miami  Beach.  Fla. 

WMC  Commercial  Appeal Memphis.  Tenn. 

WMC  A  Hotel  McAlpin  (Greenley  Square  Hotel  Co.) New  York  City 

WMH  Ainsworth-Gates  Radio  Co Cincinnati.  O. 

WNAC  Shepard  Stores Boston,    Mass. 

WN AD  University  of  Oklahoma Norman,  Okla. 

WN  AL  Omaha  Central  High  School Omaha.  Nebr. 

WNAP  Wittenberg  CoUege Springfield,  Ohio 

WNAR  First  Christian  Church Butler,  Mo. 

WNAT  Lennig  Brothers  Co.  (Frederick  Lennig) Philadelphia,  Pa. 

WNAX  Dakota  Radio  Apparatus  Co Yankton,  S.  Dak. 

WNOX  Peoples  &  Tel.  Co Knoxville.  Tenn. 

WNYC  Dept.  of  Plant  and  Structures New  York,  N.Y. 

WOAC  Page  Organ  Co Lima,  Ohio 

WOAE  Midland  College Fremont,  Nebr. 

WOAG  Apollo  Theatre  (Belvidere  Amusement  Co.) Belvidere.  111. 

WOAI  Southern  Equipment  Co San  Antonio,  Texas 

WOAN  Vaughn  Conservatory  of  Music  (James  D.  Vaughn) ....  Lawrenceburg,  Tenn. 

WOAO  Lyradion  Mfg.  Co Mishawaka,  Ind. 

WOAR  Lundskow.  Henry  P Kenosha.  Wis. 

WOAT  Boyd  M.  Hamp Wilmington, Del. 

WOAV  Pennsylvania   National  Guard,   2d   Battalion,   112th   Infantry.  ..  .Erie,  Pa. 

WOAW  Woodman  of  the  World Omaha,  Nebraska 

WOAX  Franklyn  J.  Wolff Trenton,  N.J. 

WOC  Palmer  School  of  Chiropractic Davenport.  Iowa 

WOCG  Triple  Alliance  Radio  Station Sycamore.  Illinois 

WOCL  Hotel  Jamestown,  Inc Jamestown,  N.  Y. 

WODA  James  K.  O  Dea Peterson.  New  Jersey 

WOI  Iowa  State  College Ames,  Iowa 

WOK  Neutrowound  Radio  Mfg.  Co Homewood.  111. 

WOO  John  Wanamaker Philadelphia,  Pa. 

WOR  L.  Bamberger  and  Co Newark,  N.  J. 

WORD  People's  Pulpit  Assn Batavia.  111. 

WOS  State  Marketing  Bureau Jefferson  City.  Mo. 

WOWL  Owl  Battery  Company New  Orleans.  La. 

WOWO  Main  Auto  Supply  Co Fort  Wayne,  Ind. 

WPAB  Pennsylvania  State  CoUege State  College,  Pa. 

WPAC  Donaldson  Radio  Co Okmulgee,  Okla. 

WPAJ  Doolittle  Radio  Corp New  Haven.  Conn. 

WPAK  North  Dakota  Agricultural  College Agricultural  CoUege,  N.  D. 

WPAL  Superior  Radio  &  Telephone  Equipment  Co Columbus.  Ohio 

WPG  The  Municipality  of  Atlantic  City Atlantic  City.  N.  J. 

WPRC  Wiison   Prinring  &   Radio   Co Harrisburg,  Pa. 

WQAA  Horace  A.  Beale.  Jr Parkersburg.  Pa. 

WQAC  E.  B.  Gish Amarillo.  Texas 

W  QAE  Moore  Radio  News  Station  (Edmund  B.  Moore) Springfield,  Vt. 

WQAM  Electrical  Equipment  Co -  -  Miami.   Fla. 

WQ AN  Scranton   Times Scranton     Pa. 

WQAO  Calvary  Baptist  Church New  York.  N.  Y. 

WQJ  Calumet  Rainbo  Broadcasting  Co Chicago.  HI. 

WRAF  The  Radio  Club  (Inc.) LaPorte.  Ind. 

WRAK  Economy  Light  Co Esoanaba,  Mich. 

WRAM  Lombard   College Galesburg,   IU. 

WRAQ  St.  Louis  Radio  Sorvice  Co St.  Louis,  Mo. 

WRAV  Antioch  College YeUow  Springs.  Ohio 

WRAW  Avenue  Radio  Shop  (Horace  D.  Good) Reading   Pa. 

WRAX  Flaxon's  Garage Gloucester  City,  N.  J. 

WRBC  Immanucl  Lutheran  Church -  Valparaiso.  Ind. 

WRC  Radio  Corp.  of  America Washington.  D.  C. 


218 
215 

250 
258 
273 
360 
526 
238 
254 
226 
283 
236 
222 
200 
222 
226 
209 
219 
216 
205 
210 
205 
246 
203 
211 
222 
220 
205 
231 
360 
509 
229 
352 
283 
254 
268 
306 
286 
322 
207 
207 
234 
233 
219 
270 
229 
303 
517 
405 
455 
278 
240 
261 
340 
285 
254 
231 
286 
216 
210 
275 
417 
250 
286 
283 
231 
303 
278 
278 
344 
258 
422 
288 
261 
440 
273 
256 
286 
447 
280 
261 
250 
384 
503 
341 
321 
284 
258 
255 
271 
230 
254 
248 
268 
526 
260 
280 
274 
392 
280 
369 
225 
360 
242 
526 
240 
484 
205 
275 
203 
270 
217 
509 
405 
275 
440 
270 
227 
283 
360 
268 
283 
286 
300 
216 
270 
234 
275 
283 
280 
260 
447 
224 
256 
244 
263 
2<<2 
238 
2f8 
278 
468 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


C9 


Broadcasters  Elect 

(Continued  from  page  67) 
tion  of  Censorship.  There  have  been  rumors 
of  bills  to  be  introduced  in  Congress  which 
will  require  a  broadcasting  station  to  label, 
through  announcement,  whether  a  program 
is  an  advertisement  or  not.  Discussion  on  the 
subject  covered  much  data  on  the  present 
state  of  broadcasting  for  profit.  The  final 
result  was  the  adoption  of  the  following  resolu- 
tion: 

"The  question  ha  ring  come  up  in  some  quar- 
ters as  to  whether  a  program  paid  for  by 
others  than  the  owner  of  a  broadcasting  station 
should  be  labelled  'Advertising'  or  not. 

BE  IT  RESOLVED  that  inasmuch  as  it  is 
necessary  that  the  name  of  user  of  the  station 
be  connected,  by  suitable  announcement 
with  the  program  in  order  to  derive  good  will, 
and  furthermore,  inasmuch  as  a.ny  such  an- 
nouncement or  program  if  improperly  pre- 
sented will  create  ill  will,  there  seems  no 
necessity  for  any  specific  regulation  in  regard 
to  form  of  announcement  in  connection  with 
such  paid,  or  any  other  program." 

Discussion  of  Censorship  developed  the 
following  resolution,  which  was  unanimously 
adopted. 

"WHEREAS  it  is  universally  agreed  that 
the  success  of  Radio  Broadcasting  is  founded 
upon  the  maintenance  of  public  goodwill 
and  that  no  broadcasting  station  can  operate 
successfully  without  an  appreciative  audience, 
and 

WHEREAS  the  public  is  quick  to  express 
its  approval  or  disapproval  of  broadcast  pro- 
grams. 

BE  IT  RESOLVED  that  it  is  the  sense  of 
this  meeting  that  any  agency  of  program 
censorship  other  than  public  opinion,  is  not 
necessary  and  would  be  detrimental  to  the 
advancement  of  the  art." 

No  agreement  could  be  reached  upon 
the  matter  of  Super  Power  and  therefore 
no  resolution  was  adopted.  The  trend 
of  opinion,  however,  among  the  stronger 
stations  was  definitely  toward  increased 
power,  the  only  limitation  being,  in  their 
opinion,  that  any  increase  of  power  be 
based  upon  non-interference  with  other 
stations. 

A  number  of  plans  were  submitted 
which  have  as  their  purpose  the  untang- 
ling of  the  wave  allotment  problem. 
This  matter  was  referred  to  a  committee 
at  the  next  meeting. 

All  of  the  resolutions  adopted  were 
constantly  mentioned  as  recommenda- 
tions only  to  the  Secretary  of  Commerce, 
to  aid  him,  if  possible,  in  the  many 
problems  with  which  he  is  confronted. 
It  was  the  opinion  of  members,  frequently 
expressed,  that  any  new  legislation  which 
had  for  its  purpose  the  giving  of  full 
power  to  the  Secretary  of  Commerce  to 
regulate  and  control  radio  in  all  of  its 
phases  would  be  satisfactory,  if  radio 
could  always  be  assured  of  a  Secretary 
of  Commerce  as  competent  and  as  sym- 
pathetic toward  radio  as  Secretary 
Hoover.  Fear  was  expressed,  however, 
that  some  Secretary  in  the  future  might 
not  be  competent  to  handle  the  problems 
of  radio,  and  it  was  therefore  the  opinion 
of  those  present  that  any  legislation  in- 
tended to  regulate  and  control  radio 
should  be  solely  in  the  interests  of  the 
public,  and  that  the  authority  to  so 
regulate  and  control  should  therefore 
not  be  put  in  the  hands  of  one  man. 

Upon  vote  it  was  decided  that  the 
country  be  divided  into  five  divisions, 
New  England,  Atlantic,  Great  Lakes, 
Central  and  Pacific,  with  Regional 
Chairmen  to  be  charged  with  the  duty  of 
calling  meetings  for  their  regions  when 
matters  were  up  for  decision  which  could 
not  be  delayed  until  the  time  of  meet- 
ings  of   the   whole    Association. 


Now-Plate  Voltage 
for  any  Set/— ' and 
You  can  afford  it/ 

First  Cost  Economy  now  makes  it  possible  for  EVERYONE  to 
obtain  efficient  "B"  current  supply  right  from  their  electric  light 
socket.  Now  one  of  the  biggest  improvements  in  modern-day  radio 
reception  is  placed  within  the  reach  of  all.  Think  of  it!  A  perfect, 
always  efficient  source  of  plate  voltage  for  any  set  for  $9.75!  It 
marks  a  revolutionary  step  forward  and  will  be  welcomed  by  mil- 
lions of  radio  enthusiasts. 

Ferbend 

The  price  of  this  remarkable  new  unit  is  spectacular  in  more  than 
one  way.  Besides  saving  you  from  $15  to  $50  it  is  amazingly  low 
considering  the  quality  and  superiority.  You  may  ask  "how  could  it 
be  possible  to  build  such  a  unit  for  the  ridiculously  low  price  of 
$9.75?"  True  mechanical  genius  and  resourcefulness  alone  are  re- 
sponsible. But  the  logical  way  to  answer  this  question  is  to  equip 
your  set  at  once  with  this  marvelous  unit  and  be  convinced. 

ASK  YOUR  DEALER— OR  SEND  DIRECT 

Until  nation-wide  distribution  is  com- 
pleted it  is  possible  that  your  dealer 
hasn't  stocked  the  MAXMIN  "B"  Bat- 
tery Eliminator  as  yet.  So  you  will  not 
have  to  wait,  we  will  make  prepaid  ship- 
ment direct  to  you  upon  receipt  of  $9.75, 
or  C.  O.  D.,  plus  postage.  Remember, 
superior  results  are  guaranteed  or  your 
money  back.  Be  one  of  the  first  to  own 
and  use  the  Ferbend  MAXMIM  "B" 
Battery  Eliminator. 

Use  the  COUPON  NOW! 


FERBEND 

This  company  also  man- 
ufactures the  famous 
Ferbend  WAVE  TRAP 
— the  instrument  which 
has  been  widely  imitat- 
ed but  never  equaled. 
It  is  the  only  original 
and  genuine. 


Complete,  noth- 
ing else  to  buy. 

Operates  at  max- 
imum efficiency  at 
all  times  on  either 
direct  or  alternat- 
ing current,  any 
frequency. 

Delivers  unlim- 
ited current  to  any 
receiving  set  re- 
gardless of  number 
of  tubes. 

Delivers  100  volts 
to  ANY  set. 

Cost  of  operation 
less  than  50c  a  year. 

It  lasts  indefi- 
nitely. 

All  parts  are  spe- 
cially designed  and 
manufactured  by 
us  for  this  purpose 
only. 

Unconditionally 
Guaranteed 

to    be    equal    or 
superior   to   any 


Ferbend  Electric 
Company 

431  West  Superior  Street 
Chicago,  111. 


FERBEND  ELECTRIC  CO. 

431  West  Superior  St.,  Chicago 

□  Send  Postpaid.    I  am  enclosing  $0.75. 

□  Send  C.  O.  D. .  Plus  few  cents  postage, 

□  Send  Literature. 


Name. 


Perbend  ^Hlcvx/mlrv 

IS  $timumdtot. 


City. 


THE  BIGGEST  RADIO  AGE  OF  THE  YEAR 

will  be  the  next,   the  December  issue!   More   news — more  blue- 
prints— more  hookups — and  more  features! 

And  of  course  the  predominating  feature  will  be  the  good 
receiver,  the  "Radio  Age  Model  Receiver"  that  has  been  in  the 
process  of  development  for  many  months.  The  same  receiver  that 
will  be  displayed  at  the  Chicago  Radio  Show  in  November! 
Clearly  illustrated  with  blueprints  by  John  B.  Rathbun.  The 
biggest  25  cents  worth  ever  offered!     In 

DECEMBER  RADIO  AGE— OUT  NOVEMBER  15 


*     Tested  and  Approved  by  RADIO  AGE     * 


70 


WREO 

WRHF 

WRHM 

WRNY 

WRK 

WRL 

WRM 

WRMU 

WRST 

WRW 

WSAC 

WSAI 

WSAJ 

wsan 

WSAP 

WSAR 

WSAU 

WSAV 

WSAY 

WSAZ 

WSB 

WS8C 

WSBF 

WSKC 

WSM 

WSMB 

WSMH 

WSMK 


CFAC 
CFCA 
CFCF 
CFCH 
CFCK 
CFCN 
CFCR 
CFCT 
CFCU 
CFHC 
CFKC 
CFQC 
CFRC 
CFXC 
CFYC 
CHBC 
CHCM 
CHCS 
CHIC 
CHNC 
CHUC 
CHXC 
CHYC 


RADIO  AGE  for  November,  1925 

Reo  Motor  Car  Co ■ Lansing,  Mich. 

Washington   Radio  Hospital  Fund Washington,  D.   C. 

Rosedale  Hospital,  Inc Minneapolis,  Minn. 

Experimenter  Publishing  Co New  York,  N.  Y. 

Doron   Bros Hamilton,  Ohio 

Union  College Schenectady.  N.  V. 

University  of  Illinois Urbana ,  111. 

A.  H.GreSe& Co., Inc. .Motor Yacht "MU-1" NewYork.N.Y. 

RadiotelMfg.Co..Inc Bay  Shore,  New  York 

Tarrytown  Radio  Res.  Labs Tarrytown,  N.  Y. 

Clemson  Agricultural  College Clemson  College.  S.  C. 

United  SUtes   Playing  Card  Co Cincinnati,  Ohio 

Grove  City  College Grove  City.  Pa. 

Allentown  Call   Publishing  Co Allentown,  Pa. 

Seventh  Day  AdventiH  Church New  York,  N.  Y. 

Daughty  &  Welch  Electrical  Co Fall  River.  Mass. 

Camp   Marienfield Chesham,    New   Hampshire 

C.  W.  Vick  Radio  Construction  Co Houston,  Texas 

Irving  Austin  (Port  Chester  Chamber  of  Commerce)  .  . .  Port  Chester,  N.  Y. 

Chas.   Electric   Shop Pomeroy,  Ohio 

Atlanta     Journal Atlanta.     Ga. 

World  Batley  Co 1219  S.  Wabash  Ave.,  Chicago,  III. 

Stix-Baer-Fuller  D.  G.  Co St.  Louis,  Mo. 

World's  Star  Knitting  Co Bay  City,  Mich. 

Nashville  Life  Ins.  Co , Nashville,  Tenn. 

Saenger  Amusement  Co.,  and  Maison  Blanche  Co New  Orleans,  La. 

Shattuck  Music  House Owosso.  Mich. 

S.  M.  K.  Radio  Corp Dayton,  Ohio 


286 

WSOE 

256 

WSRF 

252 

WSTA 

258 

WSUI 

360 

WTAB 

270 

WTAC 

273 

WTAD 

236 

WTAL 

216 

WTAM 

273 

WTAP 

336 

WTAQ 

325 

WTAR 

258 

WTAT 

229 

WTAW 

263 

WTAX 

254 

WTAZ 

229 

WTG 

360 

WTHS 

233 

WTIC 

258 

WTX 

428 

WWAD 

210 

WWAE 

275 

WWGL 

261 

WWGS 

WW  I 

319 

WWJ 

240 

WWL 

275 

The  Magazine  of  the  Hour 

School  of  Engineering Milwaukee.  Wis. 

Hardem  Sales  and  Service Broadlands,  111. 

Camp  Marienf eld Chesham,  N.  H. 

State  University  of  Iowa Iowa  City,  Iowa 

Fall  River  Daily  Herald  Publishing  Co Fall  River,  Mass. 

Penn    Traffic    Co Johnstown ,   Pa. 

Robt.   E   .Compton Carthage.  111. 

Toledo  Radio  &  Electric  Co Toledo,  Ohio 

Williard  Storage  Battery  Co Cleveland,  Ohio 

Cambridge  Radio  &  Electric  Co Cambridge,  III. 

S.  H.  Van  Gordon  &  Son Osseo,  Wis. 

Reliance    Electric    Co Norfolk,    Va. 

Edison  Electric  Illuminating  Co  (portable) Boston.  Mass. 

Agricultural   &    Mechanical    College   of    Texas College    Station,   Texas 

Williams    Hardware    Co Streator,  111. 

Thomas  J.  McGuire Lambertvitle,  N.  J. 

Kansas  State  Agricultural  College Manhattan,  Kans. 

Flint   Senior   High    School Flint.    Mich. 

Travelers  Insurance  Co Hartford,  Conn. 

H.    G.    Saal  Co Chicago,  111. 

Wright  &  Wright  (Inc.) Philadelphia,  Pa. 

The   Alamo   Ball  Room Joliet,  111. 

Radio  Engineering  Corp Richmond  Hill,  N.  Y. 

Radio   Engineering    Corp Richmond    Hill,    N.   Y. 

Ford  Motor  Co -Dearborn.  Mich. 

Detroit  News  (Evening  News  Assn.) Detroit,  Mich. 

Loyola  University New  Orleans,  La. 


Canadian  Stations 


Calgary    Herald Calgary.    Alta. 

Toronto  Star  Pub.  &  Prtg.  Co Toronto.  Ont. 

Marconi  Wireless  Teleg.  Co..  (Ltd.)  Canada Montreal,  Que. 

Abitibi  Power  &  Paper  Co.,  (Ltd.) Iroquois  Falls,  Ont. 

Radio  Supply  Co Edmonton,  Alta. 

W.   W.   Grant   (Ltd.) Calgary,  Alta. 

Laurentide  Air  Service Sudbury.  Ont. 

Victo-ia  City  Temple Victoria.  B.  C. 

The  Jack  Elliott  (Ltd.) Hamilton,  Ont. 

Henry  Birks  &  Sons Calgary,  Alta. 

Thorold    Hadio   Supply Thorold.   Ont. 

The  Electnc  Shop  (Ltd.) Saskatoon.  Sask. 

Queens    University Kingston .    Ont. 

Westminster   Trust   Co Westminster.   B.    C. 

Commercial   Radio    (Ltd.) Vancouver.  B.   C. 

The  Galgary  Albertan Calgary,  Alta. 

Riley  &  McCormack   (Ltd.) Calgary,  Alta. 

Tho  Hamilton  Spectator Hamilton  ,  Ont. 

Northern    Electric    Co - Toronto,  Ont. 

Toronto  Radio  Research  Society Toronto,  Ont. 

International  Bible  Ass'n Saskatoon,  Sask. 

R.   Booth ,   Jr Ottawa ,   Ont. 

Northern   Electric   Co Montreal,    Que. 


434 

CJCA 

357 

CJCL 

411 

CJCC 

500 

CKAC 

517 

CKCD 

434 

CKCK 

410 

CKCO 

329 

CKCX 

341 

CKFC 

434 

CKLC 

248 

CKNC 

329 

CKOC 

450 

CKY 

291 

CNRA 

411 

CNRC 

434 

CNRE 

434 

CNRM 

341 

CNRO 

357 

CNRR 

357 

CNRS 

329 

CNRT 

434 

CNRV 

411 

CNRW 

Edmonton  Journal Edmonton,  Alta. 

A."  Couture Montreal.  Que. 

London   Free   Press London,   Ont. 

La    Presse Montreal,    Que. 

Vancouver  Daily  Province Vancouver,  B.  C. 

Leader    Pub.    Co Regina,  Sask. 

Ottawa    Radio    Association Ottawa,   Ont. 

P.  Burns  &  Co..  (Ltd.) Caleary  ,  Alta. 

First  Congregational  Church Vancouver,  B.  C. 

Wilkinson  Electrio  Co.,   (Ltd.! Caleary,  Alta. 

Canadian  National  Carbon  Co Toronto,  Ont. 

Wentworth  Radio  Supply  Co Hamilton,  Ont. 

Manitoba  Tel .  System Winnipeg,  Man. 

Canadian  National  Railways Moncton.  N.  B. 


Canadii 


l  Natioi 
Canadian  Natio 
Canadian  Natio 
Canadian    Na 


il  Railways 


246 
233 
229 
498 
248 
360 
236 
252 
390 
242 
220 
283 
240 
280 
231 
283 
273 
218 
323 
268 
360 
242 
213 
213 
273 
352 
260 


511 
279 
321 
411 
397 
476 
434 
434 
411 
434 
357 
341 
384 
312 


.Calgary, Canada     434 


al  Railways Edmonton,  Alta.  517 

il  Railways Montreal.  P.  Q.  411 

ial  Railways Ottawa,  Ont.  434 

Canadian   National  Railways Regina,  Sask.  476 

Canadian  National  Railways Saskatoon,  Sask.  329 

Canadian   National  Railways Toronto,  Ont.  357 

Canadian  National  Railways Vancouver.  B.  C.  411 

Canadian  National  Railways Winnipeg,  Man.  384 


Constant  vigilance 
is  the  price  oF^otx^ 
uniFormitq^^o^^fc. 
and  constant  vigil- 
ance is  maintained 
over  Magnatrons* 
That  is  why  Magna- 
trons are  uniForm.and 


umformiy  good.^*^ 


b  The  Magnalron  DC-20IA,  DC-I99,  and 

f4  DC-199    (targe   base)  now   list  Jor  only 

\  $2.50  each. 

Connewey  Electric  Laboratories 
Magnatron  Bldg.      Hoboken,  N.  J. 

West  coast  supplied  from  complete  stocks  carried 

by  PACIFIC  RADIO  LAES., 

256  So.  Los  Angeles  St.,  Los  Angeles,  Calif. 


ATRONS 


R.  M.  A.  Names  Official 
Radio  Shows 

Official  announcement  has  just  been 
made  by  Herbert  H.  Frost,  President  of 
the  Radio  Manufacturers'  Association, 
that  the  Show  Committee  of  the  asso- 
ciation has  designated  the  official  shows 
of  the  manufacturers  for  1926.  These 
will  be  the  Third  Annual  Radio  World's 
Fair  in  New  York  and  the  Fifth  Annual 
Chicago  Radio  Show  in  the  latter  city. 

These  two  shows  will  be  under  the 
direction  of  U.  J.  Herrmann  and  G. 
Clayton    Irwin,    Jr. 

The  Radio  World's  Fair  next  year 
will  be  held  in  the  new  Madison  Square 
Garden,  and  the  tentative  date  approved 
for  the  opening  is  September  13. 

The  Chicago  show  next  year  will  be 
moved  forward  about  five  weeks,  October 
11  having  been  designated  for  its  open- 
ing.     It   will   be   held    in  the  Coliseum. 


NEW  SELECTIVE  CIRCUIT 

This  special  offer  includes  genuine  FULL  [ff\r* 
SIZE  blue  print  with  illustrations  and  Ov/ 
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An  ideal  circuit  for  selective  "DISTANCE  GET- 
TER" with  fine  tone,  requires  no  outside  wire. 
Operates  on  a  loop 

Werner  Radio  and  Audio  Frequency-Transformers 
are  used  in  the  above  circuit  which  consists  of  1 
stage  of  tuned  radio  frequency  amplification- for 
selectivity  and  "Pop" — followed  by  two  powerful 
untuned  stages — a  vacuum  tubedetectorand  two 
stages  of  quality  audio  frequency  amplification. 

!{,       Send  for  free  descriptive  Literature 
Werner  Radio  Mfg.  Co.,  204-206  Ninth  St.,  Brooklyn,  N.Y. 


*    Tested  and  Approved  by  RADIO  AGE    * 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


71 


Fourth  Conference  Called 

THE  Fourth  National  Radio  Confer- 
ence in  the  interest  of  public  service 
had  been  called  by  Secretary  of  Commerce 
Hoover  to  meet  in  Washington  on 
November  9th.  Representatives  of  all 
radio  interests  are  invited  to  participate, 
and  should  consider  this  notice  an  invi- 
tation to  be  present. 

For  the  first  time  the  members  of  the 
Press  are  called  in  to  represent  the 
public  especially  in  matters  affecting 
hroadcasting.  Special  letters  to  some 
400  magazines  and  newspapers  having 
radio  departments  are  going  out  asking 
that  each  publication  send  a  delegate 
to  represent  the  public  at  the  national 
sessions,  which  will  carry  on  for  about  a 
week.  This  method  of  selecting  dele- 
gates, it  is  believed,  will  guarantee  to  the 
fans  the  best  possible  representation. 

The  conference,  Secretary  Hoover 
points  out  is  called  for  the  general  discus- 
sion and  consideration  of  matters  affect- 
ing radio  communication  in  the  United 
States.  The  delegates  called  in  will 
represent  the  following  groups:  broad- 
casters, press  associations,  radio  maga- 
zines and  newspapers,  radio  set  manufac- 
turers, organized  broadcast  listeners, 
amateur  organizations,  commercial  land 
and  marine  interests,  radio  trade  asso- 
ciations, Governmental  departments,  en- 
gineers, electric  light  and  farm  organiza- 
tions interested  in  radio. 

The  heads  of  the  above  organizations 
and  groups  should  communicate  with 
Secretary  Hoover  before  October  26, 
advising  him  who  their  representatives 
will  be.  No  persons  will  be  recognized 
as  a  delegate  whose  name  is  not  filed 
with  the  Commerce  Department  before 
the  above  date. 

The  major  problems  scheduled  for  dis- 
cussion include:  interests  of  the  listening 
public  in  broadcasting;  saturation  in 
broadcasting  channels  and  necessity  for 
limitation  of  stations  on  basis  of  public 
service;  requirement  of  construction 
permits  prior  to  building  of  broadcasting 
stations;  wavelengths  or  frequencies 
for  the  several  radio  communication 
groups;  use  of  high  power  in  broadcast- 
ing; location  of  stations  outside  congested 
centers  to  prevent  interference;  alloca- 
tion of  channels  with  regard  to  time  and 
geographical  distribution;  use  of  broad- 
casting for  publicity;  amateur  activities; 
and  rebroadcasting. 


Bakelite  Used  in  Loud  Speaker 
Horns 

The  first  loud  speakers  for  radio  were 
patterned  after  the  morning-glory  type 
of  horn  used  in  the  early  phonographs. 
Radio  fans  quickly  began  to  realize 
that  the  resultant  sounds  were  not 
all  that  they  should  be,  and  the  loud 
speaker  came  in  for  its  share  of  the 
blame. 

Tin,  thin  sheet  iron  and  other  metals 
that  have  a  definite  rate  of  vibration, 
have  a  metallic  or  harsh  sound  when 
used  in  the  construction  of  amplifying 
horns.  It  has  been  found  that  inert 
materials,  such  as  paper,  wood  pulp 
and  mineral  compositions,  and  other 
substances  that  are  neutral  as  far  as 
vibration  is  concerned  are  best  for  loud 
speaker  horns.  The  best  materials  from 
an  accoustical  standpoint,  however,  are 
usually  very  fragile. 

Bakelite,  a  substance  formed  by  a 
composition  of  phenol  and  formaldehyde 
under  heat  and  pressure,  has  been  found 
ideal    for    loud    speaker    horns, 


Nc 


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Wa  print  special  postal  "Thanlt  You"  cards  that  get 
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72 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


They're   Nearly  All  Gone! 
Get  Your  "Annual"  Now! 


Ms  Worth  It: 

THE  RADIO  AGE 

ANNUAL  for  1925  is 
worth  every  cent  of 
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THE  edition  of  RADIO  AGE  ANNUALS  that 
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The  ANNUAL  contains  not  only  scores  of  tested 
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every  type  of  hookup,  from  crystal  to  super-het, 
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Some  of  the  Features 


How  to  read  and  understand  hookups. 

How  to  understand  radio  phenomena. 

Building  your  first  simple  set. 

How  to  select  the  right  receiver. 

Substituting  a  tube  for  a  crystal — building  the  first  tube  set. 

How  to  amplify  any  kind  of  set. 

Making  a  reflex  set. 

Building  your  first  Reinartz  set. 

The  renowned  Baby  Heterodyne  No.  1. 

Adding  audio  and  radio  stages  to  the  Baby  Het. 

How  to  make  a  battery  charger. 

How  to  make  a  loud  speaker. 

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How  to  get  rid  of  interference. 

How  to  make  an  amplifying  unit. 

How  to  recognize  and  deal  with  every  kind  of  tube  trouble. 

Another  super-heterodyne  for  the  super  experimenters. 

Hints  on  tracing  troubles  in  super-heterodyne  circuits. 

A  three-tube  long  distance  regenerator. 

A  3-tube  set  that  easily  receives  KGO  on  the  loud  speaker 
from  Ohio. 

Improving  the  ever  popular  Reinartz. 

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11-25 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


73 


Mar-Co  Vernier  Dial 
Is  Unique 

All  radio  apparatus  requires  a  sensitive 
indicating  device  for  the  careful  calibra- 
tion of  a  particular  setting  of  the  instru- 
ments. Such  an  indicator  must  be  care- 
fully designed  in  order  to  include  in  its 
operation  all  the  good  points  that  are 
required. 

In  building  the  Mar-co  Vernier  Dial, 
the  greatest  care  has  been  taken  to  in- 
clude desirable  features.  In  the  first 
place,  the  hair  line  indicator  in  combina- 
tion with  the  double  scale  graduated  in 
half  points  gives  a  sight  reading  compara- 
ble to  the  indicators  on  the  highest  types 
of  engineering  instruments.  The  fact 
that  the  hair  line  is  close  to  and  extends 
across  it  destroys  the  error  due  to  parallax 
which  is  the  most  common  defect  in 
radio  dials  using  an  indicator  engraved 
on  the  panel  at  some  distance  from  the 
dial  scale.  The  fact  that  the  indicator 
is  built  into  the  Mar-co  Dial  also  elimin- 
ates the  necessity  for  providing  a  sepa- 
rate indicator. 

The  Mar-co  Vernier  Dial  has  no  back 
lash,  and  is  non-microphonic.  It  does 
not  use  worm  or  spur  gearing  which  is 
rough  in  action  and  extremely  hard  to 
assemble  without  play  or  shake,  nor 
does  it  use  rubber  or  cork  friction  washers 
which  quickly  wear  out  and  cause  trou- 
ble. In  this  dial  a  special  split  metal 
pinion  is  provided  as  a  part  of  a  friction 
bevel  gear  train  which  will  last  indefinite- 
ly. The  resultant  operation  is  noiseless, 
extremely  smooth  and  extraordinarily- 
sensitive. 

The  Mar-co  Vernier  Dial  is  housed  in  a 
black  bakelite  base  carefully  designed  to 
harmonize  with  any  panel  arrangement. 
Mounting  requires  the  drilling  of  but  one 
hole  to  provide  for  the  panel  stud.  A 
special  template  is  provided  with  the 
instrument  for  this  purpose. 

A  new  and  original  feature  of  the  Mar- 
co Vernier  Dial  is  the  means  provided  for 
the  registration  of  call  letters.  Two 
apertures  are  provided  in  the  face  of  the 
dial  housing,  through  which  pencil 
notations  may  be  made  on  a  specially 
prepared  surface  to  correspond  with 
dial  settings,  providing  a  most  conven- 
ient means  of  reference. 


Globe  Loud  Speaker 

The  Globe  Phone  Mfg.  Company, 
Reading,  Mass.,  for  nearly  20  years 
makers  of  supersensitive  acoustical  de- 
vices, including  earphones  for  the  deaf, 
the  Vactuphone,  a  vacuum  tube  device 
for  the  hard  of  hearing,  auditorium 
phones,  and  earth  stethoscopes,  now 
announce  the  development  of  a  new 
Globe  Loud  Speaker. 

Built  on  an  entirely  new  principle 
the  Globe  Loud  Speaker  has  a  Silicon 
steel  diaphragm,  extra  large  drop-forged 
magnet  with  carefully  balanced  coils 
mounted  on  a  sound  bridge  with  a  special 
tone  pocket  beneath.  This  gives  a  sur- 
prising smoothness  of  tone  and  faithfully 
reproduces  music  or  the  spoken  word  in 
full,  deep,  mellow  tones  throughout  the 
entire  acoustical  range. 

A  vibrationless  horn  is  used  and  it  is 
claimed  that  all  unpleasant  overtones 
are  eliminated  and  that  the  speaker  is 
excellent  for  distant  reception. 

Careful,  accurate  and  expert  factory 
adjustment  assures  maximum  volume 
regardless  of  the  type  of  receiving  set 
used. 


Electrical  Research  Laboratories 


* 


Mfd.   under  Lotvenstein 
Patents,  March  5,  1918. 


Ecpii  Space  Gives  Ideal 
Tuning  at  all  Wavelengths 

Spreads  low  wavelength  stations  without  crowding  those 
from  50°  to  100°.    Lightweight  and  compact  in  style. 


HERE  is  a  new  con- 
denser that  surpasses 
all  present-day  types.  The 
conventional  straight  line 
frequency  condenser 
spreads  stations  on  the 
low  wavelength  propor- 
tions on  the  dial  but  it  also 
brings  stations  between 
50  and  100  too  close  to- 
gether. On  the  higher 
wavelengths  are  many  high- 
powered  stations  that  are 
extremely  difficult  to  sepa- 
rate. 

The  Erla  *Equi  Space 
makes  allowance  for  this. 
It  gives  maximum  spreads  between  stations 
over  the  entire  range  of  the  dial.  Specially 
designed  plates  make  this  possible. 

Now  all  stations,  low  frequency  as 
well  as  high  frequency,  are  spaced  on 
the  dial  to  insure  the  best  results.  Tun- 
ing is  made  far  sharper.  Sensitivity  is 
greatly  increased,  reducing  losses  to  an 
unprecedented  minimum.  Plates  of  spe- 
cial spring  brass  are  scientifically  spaced 
and  give  maximum  conductivity.  Scien- 
tific tests  show  a  resistance  far  lower 
even  than  costly  laboratory  types. 


Special  Erla  Features 

Minimum  capacity  only  10  m.m.f. 
Ratio  of  maximum  to  minimum 
capacity  35  to  1. 

Total  resistance  of  only  3  ohms 
at  1000  cycles. 

Four  riveted  cross  members  sup- 
potting  stator  plates  ptovide  ri- 
gidity unapproached. 
Single-hole  mounting  makes  it 
easy  and  quick  to  attach. 
Light  weight  plates  of  special 
spring  brass  appreciably  reduce 
bulk  and  weight,  and  tremen- 
dously reduce  tendency  toward 
misalignment  from  rough  usage. 


Equi  Space  is  small  and 
compact,  requiring  little 
space.  Very  light  but  hav- 
ing extreme  rigidity  be- 
cause of  four  riveted  cross 
members. 

Go  to  any  radio  store 
and  see  this  amazing  con- 
denser today.  It  will  make 
a  striking  difference  in  any 
set. 

Send  your  name  and 
address  today  and  we  will 
mail  free,  news  of  the 
latest  radio  discoveries 
and  inventions. 
Trade  Mark  Registered 

Electrical  Research  Laboratories 
CHICAGO,  U.  S.  A. 

—  ~  ™  ™      SeptTo-t^ 

Electrical   Research  Laboratories, 

2500    Cottage    Grove    Ave.,    Chicago,    I1L. 

Tell  me  what's  new  in  radio. 

Name 

Address - 

City 

County State 


"THE  BEST  RADIO  MAGAZINE  PRINTED1 ' 

— is  the  verdict  of  thousands  of  broadcast  enthusiasts  who 
have  voluntarily  written  to  RADIO  AGE  of  their  apprecia- 
tion. Every  month  come  additional  praises  for  the  newsy, 
interesting  material  to  be  found  in  our  pages. 

Are  you  a  regular  subscriber?  $2.50  a  year,  postpaid  any- 
where. Subscribe  NOW  if  you  want  to  be  sure  of  getting 
the  big  December  issue,  with  its  eight  page  section  devoted 
entirely  to  the 

"RADIO  AOF  M^P?* ER>„ 


74  RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


ORIOLE! 


The  Most  Amazing  Performer 

You've  Ever  "Tuned  In" 


# 


Oriole — Model  7 — 5  Tubes 


Oriole  radio  receivers  step  right  out  and  make  astounding 
records  on  distant  stations — they  give  exceptional  volume 
— unequaled  for  clarity  and  sweetness  of  tone — the  most 
selective,  sharpest  tuning  set  you  ever  played  with — 
you'll  be  "sold"  on  the  ORIOLE  the  minute  you  turn  its 
dials. 

Model  7 — 5  Tubes.     Model  8 — 4  Tubes. 
Write  for  illustrated  folder. 

Dealers:      There  is  some  exclusive   territory  open- 
ask  for  details. 

W-K  Electric  Co. 

KENOSHA,  WISCONSIN 


New    Mu-Rad    Receiver    Has 
One  Dial  Control 

THE-  factory  of  the  Mu-Rad  Radio 
Corporation  is  ideally  located,  so  it 
is  small  wonder  its  engineers  have  been 
able  to  turn  out  a  receiver  that  is  a  help 
to  the  industry. 

The  new  Mu-Rad  is  a  one  dial  tuning 
control  and  there  are  no  other  tuningad- 
justments  of  any  kind.  The  circuit  and 
control  system  were  completed  last 
January,  and  all  through  the  Spring  and 
Summer  have  been  subjected  to  the  most 
careful   tests   under   various   conditions. 

There  are  two  stages  of  tuned  radio 
frequency  amplification,  detector,  and 
two  stages  of  audio  frequency  ampli- 
fication with  a  new  type  of  fieldless  R.  F. 
transformer  coil  and  a  new  method  of 
tuning  through  one  manual  control. 
There  are  no  verniers  or  tuning  com- 
pensation devices.  The  tuning  is  ex- 
tremely sharp  on  all  wavelengths  and 
the  receiver  can  be  used  on  any  antenna 
in  any  location.  A  very  slight  turn  of 
the  knob  shuts  out  powerful  local  stations 
and  brings  in  the  distant  stations  with 
good    volume. 

The  cabinet  is  two  toned  mahogany 
of  finest  furniture  construction  and 
finish.  It  is  33  1-2  inches  long,  12  1-2 
high,  and  14  wide.  It  contains  com- 
partments for  A,  B  and  C  batteries  and 
may  be  operated  on  an  inside  or  outside 
antenna.  The  single  control  simplifies 
the  tuning  so  that  the  most  unmechanical 
person  can  bring  in  stations. 


YOU  CAN  GET 

Greater     reflex     or    crystal   eet^ 

BROWNLIE 
VERNIER  DETECTOR 

$2.00  At  your  dealer  or  Direct. 

ROLAND  BROWNLIE  &  CO. 

21  Sanders  St.  Medford  Mass. 


End  your  Radio  Troubles  for  30c  in  Stamps 

We  have  laid  aside  a  limited  number  of  back  issues  of  RADIO  AGE  for  your  use.  Below  are  listed  hookups  to  be  found 
in  these  volumes.  Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired.  The  supply  is  limited,  so  enrich  your 
store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 


January,  1924 

— Tuoiiig  Out  Interference — Wave  Trap* — E  limine  tons 

—Filters 

— A  Junior  Super-Heterodyne. 

— Puah-Pull  Amplifier. 

— Roeenbloom  Circuit. 

March,  1924 

— An  Eight-Tube  Super-Heterodyne. 
— A  dimple,  low  loss  tuner. 
■ — A  Tuned  Radio  Frequency  Aplifier. 
— Simple  Reflex  Set. 

April,  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated). 

—A  Ten  Dollar  Receiver. 

— Anti-Body  Capacity  HookupB. 

— Reflexing  the  Three-Circuit  Tuner. 

— Index  and  first  two  installments  of  Radio  Age  Data  Sheeta, 

May    i**% 

— Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

— Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

— Important  Factors  in  Constructing  a  Super-Heterodyne. 

— A  Universal  Amplifier. 

—A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 

—Radio  Age  Data  Sheets. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 

— Operating  Detector  Tube  by  Grid  Bias. 

— A  Three-Tube  Wizard  Cirouit. 

— Data  Sheets. 

Auruat,  1924 

— Breaking  Into  Radio  Without  a  Diagram 

— The  English  4-El«ment  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 

RADIO  AGE,  INC., 


September,  1924 

— How  careful  Mounting  Will  Improve  Reception. 

— One  Tuning  Control  for  Hair "b  Breadth  Selectivity. 

— Four  Pages  of  Real  Blueprints  of  a  New  Baby  Heterodyne 
and  an  Aperiodic  Variometer  Set. 

—Data  Sheeta. 

October,  1924 

— An  Easily  Made  Super-Het. 

— Two  Radio  and  Two  Audio  for  Clear  Tone. 

— A  Simple  Regenerative  Set. 

— The  Ultradyne  for  Real  DX. 

— Real  Blueprints  of  a  3-Tube  Neutrodyne  and  a  Midget 
Reflex  Set. 

November,   1924 

— Blueprints  of  a  Single  Tube  Loop  Set  and  a  Capacity  Feed- 
back Receiver. 

— A  3-Tube  Low  Loss  Regenerator. 

— Mastering  the  3-Circuit  Tuner. 

December,  1924 

— Blueprints  of  a  New  8-Tube  Super-Heterodyne. 

— How  to  Make  a  Receiver  that  Minimizes  Static. 

— A  Trans-Atlantic  DX  Receiver. 

— How  to  Make  a  Home  Made  Battery  Charger  and  a  Loud 
Speaker  at  a  Small  Cost. 

January,  1925 

— A  Reflexed  Neutrodyne. 

— A  Six  Tube  Super-Het. 

— An  Efficient  Portable  Set. 

— A  Tuned  Plate  Regenerator 

— Making  a  Station-Finder. 

February,  1925. 

— A  Sure  Shot  Super-Het. 

— A  Three  Circuit  Regenerator. 

— A  Real,  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex. 

March,  1925. 

— A  Permanent  Sup-Het. 

—A  6-Tube  R.  F.  Receiver. 

— How  to  Wind  Low  Lose  Coils. 

— A  Short  Wave  Receiver. 

— Blueprints  of  a  Two-Tube  Ultra  Audion  and  a  Regenerative 
Reflex. 


April,  1925 

— A  3-Tube  Portable  Set. 

— "B"  Voltage  from  the  A.  C  Socket. 

—An  Amplifier  for  th  3-Circuit  Tuner. 

— Blueprints  of  a  Five-Tube  Radio  Frequency  Receiver. 

May,  1925. 

— A  "Quiet"  Regenerator. 

— A  Power  Supply  Receiver. 

—How  to  Make  a  Tube-Tester. 

— A  Unique  Super-Het  and  an  Improved  Reinarto. 

— A  Six  Tube  Portable  Receiver  Illustrated  with  Blueprinta 

June,  1925. 

— Reducing  Static  Disturbances 

— A  Seven-Tube  Super-Heterodyne. 

— The  Double  Grid  Tube  in  Ordinary  Seta. 

— Browning- Drake  Receiver. 

— Overcoming  Oscillations  in  the  Roberts  Receiver. 

— An  Ideal  Set  in  Practical  Form. 

— Soldering  Secrets. 

July,  1925 

— Learning  Tube  Characteristics. 

— How  Much  Coupling? 

— The  Six-Tube  Super- Autodyne. 

— A  Simplified  Portable  Super-Het. 

— Blueprints  of  Conventional  Radio. 

— Symbols  and  Crystal  Detector  Circuit. 

August,  1925 — 50c  per  copy 

— How  to  Attain  Smooth  Tuning. 

— Alternating  Current  Tubes. 

— Deciding  on  a  Portable  Super — 

— And  a  big  60-page  blueprint  section,  in  which  is  contained 
blueprints  of  all  the  basic  circuits  from  which  all  radla 
hookups  bave  been  developed  since  the  birth  of  Radio. 

September,  1925 

—Thirty-one  ways  to  prevent  self-oscillationn. 

— Tuning  efficiency  with  two  controls 

—Ideal  Audio  Amplifier  Circuits. 

— Blueprint  section. 

October.  1925 

— Auto-T'unsformer  Coupling 

— Some  Farts  about  Quality 

— An  Improved  Slide-Wi-e  Bridere 

— Blueprints  of  Circuits  Using  Single  and  Dual  Controls. 


500  N.  DEARBORN  ST.,  CHICAGO 


*     Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  November,  1925 


7  'he  Magazine  of  the  Hour 


15 


A  Guide  to  Readers  who 
Want  Radio  Books 

IN  THE  belief  that  our  readers  will  be 
interested  in  knowing  where  to 
obtain  booklets  on  various  radio 
subjects,  from  manufacturers,  engineers, 
and  other  sources,  RADIO  AGE  is 
beginning  this  month  the  publication  of 
a  directory  for  such  literature. 

The  title  of  the  booklet,  the  person  or 
company  from  whom  it  can  be  obtained, 
and  the  latter's  address,  are  given  for 
your  convenience.  This  service  will  be 
continued  from  month  to  month  in 
RADIO  AGE,  and  readers  desiring  to 
know  where  to  get  literature  not  listed 
herewith  may  obtain  this  information  by 
addressing  our  Technical  Department. 

The  directory  for  this  month  follows: 

Aero_  Booklet.  Aero  Products,  217  N. 
Desplaines  St.,  Chicago,  Illinois. 

Henninger  Folder.  A.  F.  Henninger, 
4509  Ravenswood  Ave.,  Chicago,  Illinois. 

Log  Book  &  Catalog.  Economy  Radio 
Sales,  288  6th  Ave.,  Dept.  C,  New  York, 
New  York 

Literature.  Ferbend  Electric,  431  W. 
Superior  St.,  Chicago,  Illinois. 

Descriptive  Folder.  Hammerlund- 
Roberts  1182-D  Broadway,  New  York, 
N.  Y. 

Booklet  31,  Bakelite,  Corporation, 
247  Park  Ave.,  New  York,  N.  Y. 

Catalog.  Daven  Radio  Corporation, 
158  Summit  St.,  Newark,  N.  J. 

Descriptive  Folder.  Telephone  Main- 
tenance, 20  S.  Wells  St.,  Dept.  C,  Chicago 
Illinois. 

Descriptive  Folder.  Silver-Marshall, 
Inc.,  Dept.  C,  114  S.  Wabash  Ave., 
Chicago,  Illinois. 

Rich  Rewards  in  Radio.  Nat'l  Radio 
Institute,  Washington,  D.  C,  Dept., 
53NB. 

Better  Tuning  (10c).  Bremer-Tully, 
Dept.  53NB,  532  S.  Canal  St.,  Chicago, 
Illinois. 

Millions  Untouched.  American  Radio 
Engrs.,  Hearst  Square,  Dept.  15,  Chicago, 
Illinois. 

Catalog.  Standard  Radio  Company, 
1424  Walnut  St.,  Kansas  City,  Mo. 

Descriptive  Folder.  Allen-Bradley, 
289  Greenfield  Ave.,  Milwaukee,  Wis- 
consin. 

Catalog.  Pacent  Electric,  91  Seventh 
Ave.,  New  York. 

Catalog.  Crosley  Radio,  Cincinnati, 
Ohio.,  Dept.  63. 

15- B  Radio  Catalog.  Jewell  Electrical, 
1650  Walnut  St.,  Chicago,  Illinois. 

Catalog.  Randolph  Radio  Corpora- 
tion., 159  N.  Union  Ave.,  Chicago,  III., 
Dept  94. 

Free  Hook-Up.  Radiall  Company,  50 
Franklin  St.,  Dept.  R.  A.,  New  York, 
N.  Y.  11-50. 

Catalog.  W.  C.  Braunn,  34-50  S. 
Clinton  St.,  Chicago,  Illinois. 

Catalog.  Barawik  Company,  103-126 
S.  Canal  St.,  Chicago,  111. 

Ozarka  Instructions  No.  200  Ozarka, 
Inc.,  122A  Austin  Ave.,  Chicago,  Illinois 

Ozarka  Plan  No.  100,  Ozarka,  Inc.  122A 
Austin  Ave.,  Chicago    Illinois. 

Catalog.  Montgomery  Ward  &  Co., 
Chicago,  111.,  Dept.  18-R 


Set  Builders  Save  Space  With 
DUPLEX  CONDENSERS 

Specially  designed  shaped-out  stators  make 
these  straight-line  frequency  condensers  as 
small  as  ordinary  condensers.  Write  for 
literature.  S& 

DUPLEX  CONDENSER  &  RADIO  CORP. 
42  Flatbuah  Ave.  Extension,   Brooklyn,  N.  Y. 


Quam  Condensers 

With  The  Pyrex  End  Plate 

are  world  be&ters 


* 


This  is  an  actual  statement  of  Fact!  Pyrex  is  the  oest 
insulating  material  known.  It  is  used  by  the  U.  S.  Navy, 
Bureau  of  Standards  and  the  majority  of  the  broad- 
casting stations  of  the  world.  The  Pyrex  end  plate  is  one 
of  the  features  that  makes  the  Quam  the  lowest  loss  and 
highest  quality  condenser  built — showing  even  less  re- 
sistance than  the  laboratory  standard.  As  a  matter  of 
actual  fact  the  Quam  is  used  as  a  laboratory  standard 
in  many  experimental  and  testing  laboratories,  not  only 
in  America,  but  in  all  parts  of  the  world. 

Furnished  in  straight  line  frequency  and  straight  line 
wavelength  design.  Prices  .00025,  $6.00;  .00035,  $6.50; 
.0005,  $7.00  (with  a  4-inch  Bakelite  360°  Dial,  add  $1 .00) 

QUAM  Audio  Transformers  $5.00 

QUAM  RADIO  CORPORATION 

1925    S.    Western    Ave. 
Chicago,  U.  S.  A. 


WHO  GETS  THE  RADIO  AGE  MODEL 
RECEIVER? 

It  will  be  on  display  at  the  November  RADIO  SHOW 
in  Chicago,  and  will  be  GIVEN  AWAY  to  some  radio  fan 
at  the  conclusion  of  the  exposition.  Who  will  get  this 
remarkable  set — the  receiver  that  is  attracting  the  atten- 
tion of  the  entire  country? 

Further  details  in  the  December  RADIO  AGE.  Out 
November  15. 


*    Tested  and  Approved  by  RADIO  AGE    * 


76  RADIO  AGE  for  November,  1925  The  Magazine  of  the  Hour 


Investigate 

Before 

Investing 


Every  advertiser — whether  national  or  local — owes 
it  to  the  best  interests  he  represents  to  fully  inves- 
tigate every  publication's  claim  for  circulation,  etc., 
before  he  invests  in  'L white  space"  advertising. 

It  is  the  advertiser's  right  to  demand  facts,  not 
theory.  Superficial  information  is  not  the  kind  on 
which  to  build  a  successful  advertising  campaign, 
and  unless  each  copy  is  delivered  and  read,  the  ad- 
vertiser is  paying  for  waste  circulation  and  his  ad- 
vertising dollars  are  not  producing  proper  results. 

By  our  membership  in  the  Audit  Bureau  of  Circu- 
lations we  safeguard  the  advertiser's  money,  for  we 
want  it  known  that  we  make  no  claims  of  any 
nature  that  are  not  fully  substantiated  with  A.  B.  C. 
verified  reports. 

Get  our  last  report.  Know  what  you  are  buying. 
Then  invest. 


500  N.  Dearborn  St.,  Chicago 


•  RADIO  AGE- /or  November,  1925 


The  Magazine  of  the  Hour 


77 


LOG 


NEW 

64-PAGE 

Loose   Leaf  for   Revisions 
Full  of..     *k 


& 


Send     NO     Money 

Log  TOUR  radio.  This  new  perpetual  log  with  loose 
leaves  can  be  kept  up-to-date.  Revised  sheets  can  be 
secured  as  changes  occur.  Holds  500  stations.  Shows 
calls  (alphabetically),  cities,  wave  lengths,  4  dial  set- 
tings, remarks,  etc.  Station  list  by  wave  lengths. 
Stations  alphabetically  by  states  and  cities.  Valuable 
tuning  suggestions.  Station)  owners.  Trouble  aids. 
Chock  full  of  other  valuable  information.  So  convenient. 
Get  clearer  programs.  Illuminate  your  troubles.  Worth 
many    times    small   cost      Only    $1.00.      Order    Now. 

Radio  Map  FREE "%&« 

Don't    send    a    cent.      Pay    postman    after    log    and 
map    arrive.      If    you    pay    with    order    we    pay    postage. 
Money    refunded   if   not    delighted.     Tou   will  enjoy   this 
log.     Order   today — NOW.     Postal   will   do. 
RADIO    PRINTERS,      Dept    2028,      MARENGO,    ILL. 


* 


SOLD  under  a  positive  guarantee — you 
take  no  chances  when  you  buy  EM- 
PIRE-TRONS.  No  finer  tube  made  I 
Retails  in  U.  S.  A.  at  S2.50.  If  your 
dealer  cannot  supply,  write  us. 

EMPIRE  SPEAKERS 
Beautiful  in  design;  scientifically  con- 
structed; acoustically  correct.  Made  in 
all  popular  models  and  finishes.  Retail 
at  $13.50  up.  We  supply  Fibre  Horns 
to  manufacturers  cf  Loud  Speake  at 
special  prices.     Inquiries  solicited. 

EMPIRE  LOUD  SPEAKER  UNITS 
Phono-Speakers 

Equal    to    any    Unit    on    the    market. 
Retails  $6.50. 

Write  for  Illustrated  Folder  "A" 

EMPIRE  dealers  are  the  leaders 

in  every  field. 

Distributors  Wanted — Write  for  prices. 

AMER.  INTERNATIONAL  TRADING  CO. 

24-26  Slone  SL,  New  York 

Cable  address  "Stanmarks". 


EMPIRE  PRODUCTS 


If  you  want  to  be  sure 
of  getting  your  December 
RADIO  AGE,  with  its  big 
"Radio  Age  Receiver"  Fea- 
ture, Order  from  your  news- 
dealer or  subscribe  NOW! 


Operate  Your  Radio  With 
One  Switch 

"Whenever  you  make  radio  so  easy 
to  operate  that  I  can  turn  it  'on'  and 
'off'  like  an  electric  light,  with  no  batter- 
ies to  recharge  or  replace,  you  can  send 
me  the  finest  set  you  turn  out,"  wrote  a 
Congressman  recently  to  a  manufac- 
turer. 

This  Jjas  been  the  challenge  to  radio 
of  thousands  of  persons  who  have  held 
off  buying  sets  by  reason  of  real  and 
imaginary  difficulties  in  their  opera- 
tion. 

The  Congressman  referred  to  above 
has  received  his  set.  It  was  equipped 
with  a  new  power  unit  that  plugs  right 
into  a  lamp  or  wall  socket  and  trans- 
forms ordinary  electric  light  current  into 
the  smooth,  hum-free  current  necessary 
for    radio. 

One  switch  on  this  new  power  unit 
controls  everything — "A"  power,  "B" 
power,  even  the  radio  set  itself.  Snap 
it  "ON"  and  you  get  a  strong,  uniform 
flow  of  both  "A"  and  "B"  power.  Snap 
it  "OFF"  and  your  power  is  shut  off  and 
your  radio  is  silent. 

This  new  radio  power  unit  was  de- 
veloped by  the  Philadelphia  Storage 
Battery  Company  and  is  named  "Philco 
Socket  Power." 

Philco  Socket  Power  is  supplied  in 
three  general  types:  Socket  Power  B, 
to  replace  "B"  batteries  on  any  radio 
set;  Socket  Power  "A"  to  supply  fila- 
ment current  at  six  volts  for  all  sets 
having  standard  storage-battery  or  five- 
volt  tubes; and  Socket  Power "AB,"  which 
is  a  combination  filament-current  and 
plate-current  supply  for  Radiola  Super- 
Heterodyne  and  other  receiving  sets 
employing  so-called  dry-battery  or  three- 
volt  tubes. 


New  Receiver  Developed   by 
McMurdo  Silver 

RADIO  fans  will  be  interested  in  a 
new  receiver  which  is  to  be  put 
on  the  market. 
The  set  in  question  has  successfully 
passed  thorough  tests  and  has  been 
found  efficient  in  construction  and  per- 
formance. These  tests,  together  with  the 
comment  the  set  caused  at  the  Radio 
Shows  in  New  York,  Chicago  and  In- 
dianapolis, make  it  a  logical  contender 
for  popularity  this  season.  Construc- 
tion details  have  not  been  announced 
as  yet  by  the  designer,  McMurdo  Silver, 
Assoc.  I.  R.  E.,  who  has  already  made  a 
number  of  contributions  to  Radio. 

The  set  is  a  six  tube  outfit  that  anyone 
can  build  in  a  few  hours.  Three  stages  of 
resistance  coupled  audio  amplification 
result  in  a  high  quality  of  reproduction. 
The  circuit  is  very  sensitive  and  selective. 
It  is  a  marvel  of  simplicity,  and  handles 
with  equal  efficiency  all  ■  wavelengths 
above  50  meters.  The  set,  which  for  the 
time  being  is  called  the  Silver  Six,  oper- 
ates with  either  one,  two  or  three  con- 
trols as  desired,  on  either  a  loop  or  an 
antenna. 

It's  principle  and  construction  are 
startlingly  new. 

¥    Tested  and  Approved  by  RADIO  AGE    * 


For  EVERY 
Radio  Set 

A  stunning  piece  of  furniture  that 
restores  order  in  the  room  where 
you  have  your  Radio!  No  more 
cluttered  table-tops,  nor  litter  of 
equipment  un- 
der-foot. 

No  unsightly 
horn  in  evidence, 
either!  This  con- 
sole has  its  own 
loudspeaker,  in- 
built. It's  out  of 
sight,  but  with 
very  apparent 
tonal  superiori- 
ties.   For  it  has 

the     highest -de-     position  which  defeats 
.  V  ,-    vibration. 

veloped  type  or 

unit.  With  horn  built  of  special 
non-vibrating,extra-hard, ceramic 
material.  Produces  clear  non-vi- 
brant tone. 

There's  ample  room  for  every- 
thing; space  for  largest  A  and  B 
wet  batteries — or  battery  elimi- 
nator—required for  any  home  set; 
and  for  a  big  charging  outfit,  too. 

Finished  in  mahogany,  or  walnut  color. 
Dainty  design  of  parqueterie  on  two  front 
panels.  Top,  38  in.  x  18  in.  Substantially 
built;  the  product  of  a  40-year-old  furni- 
ture maker. 

The  price,  forty  dollars,  is  for  the  complete 
console  and  includes  the  loudspeaker  horn 
and  unit.  Thousands  of  dealers  are  show- 
ing this  artistic  addition  to  home  radio 
equipment. 

Rear  View— Set  Hooted  Ut 


Non- Vibrant  Ceramic 
Horn 

The  clearest  tone  pro- 
ducer on  the  market. 
Made  of  special  com- 


78 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


Radio  Parts  FREE! 

What  parts  do  you  need  to  complete  your  set,  or  what  new  parts  do  you  want  to  try  out? 
Below  is  a  list  of  premiums  we  are  offering  which  are  easy  to  get.  Look  through  the  list,  pick 
out  what  you  want  and  send  in  the  new  subscriptions  with  a  request  for  parts.  Every  item 
has  been  tested  and  approved  by  the  RADIO  AGE  INSTITUTE,  so  you  can  be  sure  of  the  best 
parts  made.   More  complete  description  will  be  sent  upon  request. 

New  premiums  will  be  added  to  this  list  each  month,  so  if  you  do  not  find  here  just  the 
item  you  want,  send  in  your  new  subscriptions  and  you  will  be  given  credit  for  them.  Your 
premiums  will  be  sent  as  soon  as  you  decide  what  you  want.  Get  in  on  this  now!  It  is  the  best 
way  to  get  guaranteed  parts  FREE.     Subscription,  $2.50  per  year. 

Send  checks  or  money  orders  with  your  letters  when  you  send  in  new  subscriptions .  Let' s  go  > 


l. 


3. 


4. 


For   ONE  new  subscription    the   following  parts  are 
offered  as  your  premiums: 
AMSCO  Bakelite  Dials,  100  graduations,  2,3  or  4 
inches. 

AMSCO  Tube  Sockets,  panel  or  table  mounting. 
EVER  READY  C  Battery. 
BURGESS  G  Battery. 
RED  SEAL  Dry  Cell  Battery. 

BREMER  TULLY  type  U  L  Socket.  Eliminates 
use  of  adapters. 

For  TWO  new  subscriptions  the  following  parts  are 
offered  as  your  premiums: 
AMSCO  Rheostats,  Arrow  Knob  or  Bakelite  Dial. 
2,  6,  8,  10,  12,  15,  20,  30,  or  50  Ohm. 
AMSCO  Potentiometers,  Arrow  Knob  or  Bakelite 
Dial.  250  or  400  Ohm. 

AMSCO  Grid-Leak  and  Condenser.  Fixed  con- 
denser, .00025  mfd.  capacity  and  Grid-Leak,  2 
Megohms. 

Genuine  non-inductive  CRESCENT  LAVITE 
Resistances.  12,000,  48,000,  50,000,  or  100,000 
ohms. 

5.  DAVEN  LEAKANDENSER.  Combination  grid 
leak  and  grid  condenser.   2,  3,  4,  5,  or  7  megohms. 

6.  DAVEN  RESISTO  Couplers.  Two  pair  of  clips, 
one  for  holding  the  plate  resistor  and  one  for 
holding  the  grid  leak. 

7.  STEINITE  Interference  Eliminator.  Enables  you 
to  tune  out  locals  and  get  distant  stations. 

8.  Small  BURGESS  "B"  Battery. 

9.  Small  EVER  READY  "B"  Battery. 

For   THREE  new  subscriptions   the  following  parts 
to  choose  from: 

1.  CRESCENT  Bakelite  Panels.  %"  thick.  Size 
7"xl0"  or  7"xl2". 

2.  BREMER  TULLY  Variable  High  Resistances. 
Maximum  resistances  of  2,000,  50,000,  100,000  or 
200,000  ohms. 

BREMER  TULLY  Volume  Control  or  Modulator. 
Used  in  audio  circuits  for  noiseless  adjustment  of 
volume  and  improvement  of  tone  qualities. 
BREMER  TULLY  Non-inductive  Potentiometer. 
A  variable  high  resistance  with  three  terminals. 
Slider  connects  to  center  terminal  and  varies  at 
either  outer  terminal  to  maximum  resistance. 
400  or  2,000  Ohm  maximum  resistance. 

FOUR 


3. 


4. 


For 


new    subscriptions    the    following    pre- 
miums to  choose  from: 

1.  KLADAG  EUPHONE,  Bakelite  base,  no  tip, 
thoriated  filament  tube.    201A  or  199  type. 

2.  CRESCENT  Bakelite  Panels.  %'  thick.  7"xl4" 
or  7"xl6"  or  7"xl8". 

3.  VAN  HORNE  3VA  "Double  Service"  or  Com- 
promise Tube.  Operates  at  3  volts  from  either 
dry  cells  or  batteries. 

4.  BREMER  TULLY  Tuning  Control.  12  to  1  ratio. 
Provides  positive  control  with  a  smooth  easy 
action.   With  disc  for  marking  station  call  letters. 

For  FIVE  new  subscriptions  you  can  pick  your  pre- 
miums from   the  following: 

1.  ENSIGN  Variable  Condenser.  Either  .00025  or 
.0005  capacity. 

2.  MUSSELMAN  Selective  Antenna.  75  foot  length 
coil. 

3.  Model  5VA,  3VA  or  3VB  MUSSELMAN  Certified 


4. 


5. 


1. 


Electron  Tubes.    5VA  and  3VA  fit  201-A  sockets 

3VB  fits  199  sockets. 

AMSCO   Allocating   Condenser.      Straight   Line 

Frequency.    13  plates  or  17  plates,  .0003  or  .00035 

mfd.  Single  unit. 

CRESCENT  Bakelite  Panel.    %"  thick.  7"x21". 

For  SIX  new  subscriptions  you  have  the  following 
to  choose  from: 

1.  The  AERO  COIL  Wave  Trap  Unit.  Makes  a  very 
efficient  wave   trap  or  crystal  set. 

2.  CRESCENT  Bakelite  Panels.  %"  thick.  7"x24"  or 
7"x26". 

3.  SILVER-MARSHALL  S.L.W.  type,  .00025,  11 
plate,  or  .00035,  17  plate,  condensers.  Silver 
plated.    Three  inches  square. 

4.  BREMER  TULLY  Three  Circuit  Tuner.  A  tuner 
of  unquestioned  merit  for  use  in  one  to  four  tube 
sets.  Two  types,  for  200  to  566  meters  reception 
and  for  50  to  150  meters  reception. 

5.  BREMER  TULLY  "Torostyle"  Transformers. 
Three  types :  Antenna  Coupler,  for  Intermediate 
R.  F.  Stages,  and  for  four  tube  sets. 

For  EIGHT  new  subscriptions  we  offer  the  following 
premiums: 
AERO  COIL  Oscillator  for  Super  Heterodynes,  as 
advertised  in  RADIO  AGE. 

CREST  Convertible  Condenser.    23  plate.    Con- 
vertible to  all  capacities.    S.L.F. 
Model    5VC    MUSSELMAN    Certified    Electron 
Tube    Fits  201  ~* A  sockets 

SILVER  MARSHALL  type  105  Low  Loss  Coupler. 
For  three  circuit,  tuned  R.F.,  or  other  circuits 
requiring  a  highly  efficient  inductance  unit. 
Wave  length  range,  with  stator  shunted  by  .0005 
mfd.  condenser,  200  to  550  meters. 
SILVER  MARSHALL  S.L.F.  type,  .0005  mfd.,  35 
plate,  or  .00035,  25  plate,  or  .00025,  17  plate 
condensers.  Silver  plated.  Three  inches  square. 
Seven  by  eighteen  inch  cabinet  with  hinged 
cover.    (SILVER  MARSHALL). 

BREMER  TULLY  "Euphonic"  Audio  Trans- 
formers. Type  210,  ratio  2.2  to  1  and  Type  410, 
4.7  to  1. 

BREMER  TULLY  S.L.F.   condensers.     13  or  17 
plate,  .00025  or  .00035  mfd. 
For  TEN  new  subscriptions  you  can  pick  your  prize 
from  this  list: 

1.  The  AERO  COIL  Three  Circuit  Tuner.  Advertised 
in  RADIO  AGE. 

2.  AMSCO  ALLOCATING  Condensers.  S.L.F.  17  or 
23  plates,  .00035  or  .0005  mfd.    Double  Unit. 

3.  KLADAG  Knock  Down,  Mahogany  Loop  An- 
tenna.   Bank  Wound,  Centre  Tapped. 

4.  STEINITE  long  distance  crystal  set.  In  beautiful 
hand-rubbed,  walnut  finish  case. 

5.  STEINITE  one  tube  regenerative  set.  1500  mile 
range.    Mahogany  cabinet. 

6.  SILVER  MARSHALL  "Two  Ten"  Transformer. 
A  long  wave  inter-stage  transformer,  peaking  at 
60  kilocycles.  Combination  iron  core  type  and 
air  core  type.  Turn  ratio,  1  to  2.3. 
SILVER  MARSHALL  "Two  Eleven"  Transformer. 
Peaks  at  60  kilocycles  in  conjunction  with  the 
tuning  condenser  supplied.  Air  core  type.  May 
be  used  at  input  or  output  end  of  the  amplifier, 
turn  ratio  1  to  10.  Complete  with  60RC  tuning 
condenser. 


8 


7. 


RADIO  AGE  for  November,  1925 


The  Magazine  of  the  Hour 


79 


CLASSIFIED  ADVERTISEMENTS 

If  you  have  anything  to  buy  or  sell,  don't  overlook  the  value  of  RADIO  AGE'S  classified 
advertisements.    Many  such  messages  have  paved  the  way  to  independent  incomes. 

The  classified  advertising  rates  are  but  ten  cents  per  word  for  a  single  insertion.  Liberal 
discounts  are  allowed  on  three,  six  and  twelve-time  insertions,  of  five,  fifteen  and  thirty  per  cent 
respectively.  Unless  placed  through  an  accredited  advertising  agency,  cash  should  accompany 
all  orders.  Name  and  address  must  be  included  at  foregoing  rates  and  no  advertisement  of  less 
than  ten  words  will  be  accepted. 

All  classified  ads  for  the  December  issue  must  be  sent  in  by  November  1. 


ADVERTISING     SERVICE 

CRYSTALS 

QUEX  Sale*   Letters    Get    More    Business.      Write  him 
today.      Quex,  4418  Michigan  Ave.,  Chicago. 

Supersensitive  Galena  Crystals:  Pound  $1.00,  prepaid. 
ALKEMITE.        Allsensitive      Crystals      50c.         Buskett, 
Geologist,  Joplin,  Missouri. 

I  AM  AN  EXPERIENCED  RADIO  ENGINEER  and  am 
now  in  a  position  to  offer  extensive  engineering  service 
to  reputable  electrical  or  radio  manufacturers.      If  you 

HELP  WANTED 

product,  you   must  have  authority  behind  your  state- 
ments   to    make    your    advertising    command    respect. 
I    will    make    necessary   experiments   on    any    technical 
product  in  radio  or  electrical  field,  and  write  dominat- 
ing technical  or  non-technical  copy.     Send  for  list  of 
references    and    explanatory    booklet.       No    obligation. 
Harvey  T.  Kelley,  Not  Inc.,  Suite  301,  210  East  Ohio  St., 
Chicago,    III. 

RADIO  SALESMEN  and  SET  BUILDERS— We  need 
you  and  you  need  us.  If  you  are  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  III. 

AGENTS  WANTED 

MEN  wanting  forest  ranger,  railway  clerk  and  other 
government  positions,  write  for  free  particulars  of 
exams.      Mokane,   Dept.    B-33.    Denver,   Colo. 

FORDS.      60  miles  on  one  gallon  of  Gas.      It  has  been 
proven   such   mileage  can   be  made.      AIRLOCK   guar- 
antees to  increase  gas  mileage;  also  prevents  radiator 
boiling  in  summer  or  freezing  in  winter.     Cools,  Fuels, 

MEN  WISHING  TO  ENTER  DINING,  SLEEPING  CAR 
SERVICE  AS  CONDUCTORS,  PORTERS,  WAITERS, 
WRITE  123  RAILWAY  EXCHANGE,  KANSAS  CITY. 

Decarbonizes     the     Ford     motor.       Splendid     territory 
open.     AIRLOCK  PRODUCTS,  Box  703G,  Willow  Street, 
Long  Beach,  Calif. 

INVENTIONS 

RADIO — Join    our    sales    organization    and    make    big 
money.     We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers.       Widener    of    Kansas    City    makes    $150.00 
weekly.      You   can   do   as  well  or   better.      Write   today 
for  catalog,  and  discounts.    Name  your  county.      Wave- 

NEW  IDEAS  WANTED— Well  known  Radio  Manufac- 
turer whose  products  are  nationally  advertised  and  sold 
everywhere  wants  new  Radio  device  to  sell.  Will  pay 
outright  or  royalty  for  idea  or  invention  which  is  really 
new  and  saleable.  Address:  Mr.  R.  F.  Devine,  Room 
1101,  116  West  32nd  St.,  New  York,  N.  Y. 

cago      Ml. 

PATENTS 

MANUFACTURER'S    AGENT    calling    on    Radio-Elec- 
trical Jobbers,  Chicago  and  vicinity,  has  opening  for  3 
additional  lines  carrying  volume  business,  as  we  cater 
to    large    jobbers.       Edelstein,    1804    McCormick    Bid., 
Chicago. 

FOR  SALE:  U.  S.  and  Canadian  Patent  on  an  Attach- 
ment for  Phonographs;  is  the  most  beautiful  inven- 
tion of  the  age.     Address  Chas.  F.  Smith,  Huff,  N.  Dak. 

Man     wanted     for     this      territory    to    sell    wonderful 
value    men's,    women's.    Children  s    shoes    direct,    sav- 
ing    consumer    over     40%.       Experience     unnecessary. 
Samples     supplied.      Big     weekly     permanent     income. 
Writ*  today  Tanners  Mfg.  Co.,  1334C.  St.,  Boston,  Mass. 

PERSONAL 

LONELY  HEARTSt  Exchange  letters;  make  interesting 
new   friends    in   our  jolly    club.      Eva    Moore,    Box   908. 

RADIO  SALESMEN  and  SET  BUILDERS  in  every  county 
write  Grenzer  Radio,   1479  Hodiamont.  St.  Louis.  Mo. 

Jacksonville,  Florida.    Enclose  stamp. 

Look!  You  Radio  Bugs!  Join  Radio  Correspondence 
Club.  Entirely  new.  Broaden  your  acquaintance, 
exchange  ideas.  Membership  open  to  LADY  BUGS 
also.  Dime  stamp  brings  pamphlet  and  Radio  Novelty 
Cards.     Radio  Rose,  Box  662,  Cleveland,  Ohio. 

AGENTS    WANTED    to    advertise    our    goods    and    dis- 
tribute samples  given  to  consumers;  90c  an  hour;  write 
for    full     particulars.        American      Products     Co.,     4201 

American  Bldg.,  Cincinnati,   Ohio. 

PRINTING 

"B"   BATTERIES 

WE  print  Stationery,  Booklets,  Catalogs,  Circulars. 
Samples.     Commercial  Press,  Batavia,  Ohio. 

down.      Parts  and  plana — complete,  $12.50.      Lane  Mfg. 
2937  W.  Lake,  Chicago. 

RADIO 

BATTERIES  FOR  SALE — Four24-volt  "Main"  Storage 
"B"  Batteries,  never  used,  shipped  and  ready  to  wire 
for    $38.00.      First    order    gets    the    batteries.     Address 
Box  B,  Radio  Age,  500  N.  Dearborn  St.,  Chicago,  111. 

A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  less  phones  and  tube.  Complete  with 
phones,  tube  and  battery,  $18.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  111. 

BUSINESS  OPPORTUNITIES 

Standard  soderless  radio  Jacks.  Binding  post  attach- 
ments. Double  circuit.  One  dollar  bill.  Postpaid. 
Clinton  Seward,  Jr.,  New  PaJtz,  New  York,  N.    Y. 

$100  weekly  up.      We  want  experienced   Radio  men  to 
operate     branch     assembling     plants.        Part     or     whole 
time.     Barfield  Radio  Co.,  13  Tillery  Street,  Dept.  A  R, 

Three  Cosmopolitan  Phusiformers,  each  $5.50,  book  of 
instructions  included.      F.   A.    Mall,   Triopli,   Iowa. 

Brooklyn,  New  York. 

15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.  Every  item  guaranteed.  Tell  us  your  needs. 
IMPERIAL  RADIO  COMPANY.  Delaware,  Ohio. 

WE  WILL  START  YOU  IN  THE  RADIO  BUSINESS  IN 
your  community  at  a  cost  'within  the  reach  of  anyonr, 
Qui-k,  steady  profits  assured  from  the  start.     Here  is 
a  real  change  to  make  big  money  in  radio  this  season. 
Write  for  details,    at    no  obligation.      KELLY   RADIO 
SUPPLY  CO.,  3312  Warren  Ave.,  Chicago,  111.,  Box  11B. 

RADIO  SETS.  Our  prices  save  you  money.  Lists  free. 
The  Radio  Shoppe,  Box  645,  East  Liverpool,  Ohio. 

AT  LAST  I  The  Radco  Static  Eliminator.  Eliminates 
50  to  90%  Static.  Many  satisfied  users.  Write  for 
particulars.  Radio  Specialties  Company,  Sioux  Falls, 
South    Dakota. 

Classified  ad.  copy  for  the  Decem- 
ber RADIO   AGE   must  be  sent  in 
by  November  lf  1925. 

$1.00  For  Your  Old  Tubes 
regardless  of  make  or  condition  towards  the  purchase 
of  each  new  Standard  $2.50  tube-    Positively  guaranteed. 
We  do  not  sell  rebuilt  or  bootleg  tubes.     Order  today. 
Luxem  &  Davis  Mfg.  Co.,  6229  Broadway,  Chicago,  III. 

RADIO  CIRCUITS 


SPECIAL  FOR  NOVEMBER 

The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne,  fully 
illustrated,  and  RADIO  AGE,  for  $2*50.  Price  of  Book- 
let alone  is  50c.  Send  check,  currency  or  money  order 
to  RADIO  AGE,  500  N.  Dearborn  Street,  Chicago. 


RADIO   DEALERS 


DEALERS — Write  for  our  illustrated  catalog  of  reliable 
Radio  Merchandise.  Rossiter-Manning  Corporation, 
Dept.  D,  1830  Wilson  Ave.,  Chicago,  111. 


RADIO  SUPPLIES 


MAKE  BIG  MONEY  BY  REPRESENTING  us  in  your 
territory  If  you  live  West  of  the  Mississippi,  where 
Radio  is  getting  more  and  more  popular,  why  not 
represent  Radiograph  Laboratories  and  make  a  splendid 
yourself  by  handling  < 


th. 


agent? 

will  interest  you. 
ribing  our  producti 
tubes,  etc. 
ints  on  request.     Sp< 


Send 


clu 


sive    proposit 
r    interesting    fo 
which  include  the  best  i 
Catalog    of    parts    with 
:ify  whether  you 


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HAVE  YOU  SEEN  THE  NEW  DIALITE,  THE  UNIQUE 
lamp  that  lights  up  your  panel  and  adds  a  decorative 
touch  to  any  radio  set?  Retails  at  $2.75,  complete. 
Send  for  folder  and  dealer's  proposition  on  this  fast 
moving  article.  Also,  we  are  distributors  for  the  famous 
Knurled  Walnut  Cabinets,  the  moat  beautiful  cabi- 
nets made.  American-Universal  Radio  Co.,  6255 
Broadway,  Chicago,  111.,  Box  11. 


SALESMEN  WANTED 


Make  $100  WEEKLY  in  spare  time.  Sell  what  the 
public  wants— long  distance  radio  receiving  sets.  Two 
sales  weekly  pays  $100  profit.  No  big  investment, 
no  canvassing.  Sharpe  of  Colorado  made  $955  in  one 
month.  Representatives  wanted  at  once.  This  plan 
is  sweeping  the  country — write  today  before  your 
county   is    gone.     UZ.ARKA,    INC.,    126  V    West   Austin 

STAMPS,  50  varieties,  Africa,  Brazil,  Peru,  Cuba, 
Mexico,  etc.,  10c.  50  different  U.  S.,  25c;  1.000  mixed, 
40c;  1,000  hinges,  10c.  List  free.  C.  Stegman,  5950 
Cote  Brilliante,  St.  Louis,  Missouri. 


VOCATIONS 


Make    Big    Money.       Safe    and    Lock    Expert.       Wayne 
Strong,  3800  Lan  Franco  St.,  Los  Angeles,  Calif. 


WANTED 


WANTED — To  complete  my  set  RADIO  AGE  need 
August,  September,  October,  November,  1923,  issues, 
bound  or  unbound.  Advise  price.  Lloyd  C.  Henning, 
Hollbrook.    ' 


WIRELESS 


WANT  TO  MEMORIZE  THE  WIRELESS  CODE?  The 
Coryden  Snyder  Code  Method.  Patented,  is  quickest. 
Send  50c  ccin.  stamps  or  M.  O.  to  C.  G.  Snyder.  1423 
Elmdaie  Ave.,  Chicago.  III. 

TELEGRAPHY— Morseand  Wireless— taught  at  home 
in  half  usual  time  and  at  trilling  cost.  Omnigraph 
Automatic  Transmitter  will  send,  on  Sounder  or  Buz- 
zer, unlimited  messages,  any  speed,  just  as  expert 
operator  would.  Adopted  by  U.  S.  Govt,  and  used  by 
,  Colleges,  Technical  and  Telegraph 
-       Omnigraph 


leading  UnivD.D 

Schools  throughout  U.  S.     Catalog  free. 

Mfg.  Co.,  13  F  Hudson  St.,  New  York. 


WRITERS 


WRITERS— Cash  in  on  your  knowledge  of  radio  by 
writing  for  Radio  Magazines  and  Newspaper  Supple- 
ments. Write  up  your  radio  experiences,  your  new 
hook-up,  your  knowledge  of  broadcasting  stations  and 
artists.  Experienced  authors  will  correct  and  improve 
your  manuscripts—make  them  typically  professional 
work.  FREE  Criticism  and  Advisory  Service  until  your 
manuscript  is  soldi  ALL  Magazines  and  Papers  de- 
manding fiction  and  articles  dealing  with  radio.  Here 
is  YOUR  OPPORTUNITY  to  profitl  Send  for  FREE 
booklet,  "How  You  Can  Sell  Your  Manuscripts." 
Willis  Arnold  and  Associates,  210  East  Ohio  St. 
Chicago,  111 


*     Tested  and  Approved  by  RADIO  AGE     * 


80 


RADIO  AGE  for  November,  1925 


THE    RADIO    AGE 
BUYERS'   SERVICE 

What  do  you  want  to  purchase  in  the  radio  line?  Let  the  staff  of  RADIO  AGE  save  you 
time  and  money  by  sending  in  the  coupon  below.  Enter  the  number  of  the  article  you 
would  like  to  know  more  about  in  the  spaces  provided  in  the  coupon. 


1  "A"  Batterle* 

2  Aerial  protectors 

3  Aerial  insulator* 

4  AeriaU 

5  AeriaU.  loop 

6  Amplifiers 

7  Amplifying  units 

8  Ammeters 

9  *'B"  batteries 

10  Batteries   (state  voltage* 

11  Batteries,  dry  cell 

12  Batteries,  storage 

13  Battery  chargers 

14  Battery  clips 

15  Battery  plates 

16  Battery  substitute* 

17  Bezels 

18  Binding  posts 

19  Binding  posts,  Insulated 

20  Books 

21  Boxes,  battery 

22  Boxes,  grounding 

23  Bridges,  wheatatone 

24  Broadcasting  equipment 

25  Bushings 

26  Buzxers 

27  Cabinets 

28  Cabinets,  battery 

29  Cabinets,  loud  speaker 

30  Carbons,  battery 

31  Cat  whiskers 

32  Code  practisars 

33  Coils 

34  Coils,  choke 

35  Coils,  coupling 

36  Colls,  filter 

37  Colls,  grid 

38  Coils,  honeycomb 

39  Coils,  inductance 

40  Coils,  Reinart* 

41  Coils,  stabilizer 

42  Coils,  tuning 

43  Condenser  part* 

44  Condenser  plates 

45  Condensers,  antenna  coup- 
ling 

46  Condensers,  by-pass 

47  Condensers,  coupling 

48  Condensers,  filter 

49  Condensers,  fixed  (paper, 
grid,  or  phonal 

50  Condensers,  variable  grid 

51  Condensers,  variable  mica 

52  Condensers,  vernier 

53  Contact  points 

54  Contacts,  switch 

55  Cord  tips 

56  Cords,  for  head  sat* 

57  Couplers,  loose 

58  Couplers,  molded 

59  Couplers,  varlo 

60  Crystal  alloy 

61  Crystal  holders 

62  Crystals,  rough 

63  Crystals,  mineral 

64  Crystals,  synthetic 

65  Crystals,  unmounted 

66  Crystals,  mounted 

67  Desks,  radio 

68  Detector  unit* 

69  Detectors,  crystal 

70  Detectors,  fixed  crystal 

71  Dial,  adjusters 

72  Dials,  composition 

73  Dials,  hard  rubber 

74  Dials,  rheostat 

75  Dials,  metal 

76  Dials,  vernier 

77  Dials  with  knobs 

78  Dies 

79  Drills,  electric 

80  Dry  cells 

81  Earth  grounds 

82  Electrolyte 

63   Enamels,  battery 

84  Enamels,  metal 

85  End  stops 

86  Eyelets 

87  Experimental  work 

88  Fibre  sheet,  vulcanised 

89  Filter  reactor*; 

90  Fixtures 

91  Fuse  cut  out* 

92  Fuses,  tube 

93  Generators, high  frequency 

94  Grid  choppers,  rotary 


95  Grid  leak  holders 

96  Grid,  transmitting  leaks 

97  Grid  leaks,  tube 

98  Grid  leaks,  variable 

99  Grinders,  electric 

100  Ground  clamps 

101  Ground  rods 

102  Handles,  switch 

103  Head  bands 

104  Head  phones 

105  Head  aets 

106  Honeycomb  coil  adapters 

107  Hook  ups 

108  Horns,  composition 

109  Horns,  fibre 

110  Horns,  machc 

111  Horns,  metal 

112  Horns,  wooden 

113  Hydrometers 

114  Indicators,  polarity 

115  Inductances,  C.  W. 

116  Insulation,  molded 

117  Insulation  material 

118  Insulators,  aerial 

119  Insulators,  composition 

120  Insulators,  fibre 

121  Insulators,  high  voltage 

122  Insulators,  cloth 

123  Insulators,  glass 

124  Insulators,  hard  rubber 

125  Insulators,  porcelain 

126  Irons,  soldering 

127  Jacks 

128  Filament  control 

129  Jars,  battery 

130  Keys,  transmitting 

131  Knobs 

132  Knock-down  panel  units 

133  Laboratories,  testing 

134  Lever,  switch 

135  Lightning  arresters 

136  Loosecouplers 

137  Loud  speakers 

138  Loud  speaker  unit* 

139  Lugs,  battery 

140  Lugs,  terminal 

141  Measuring  instruments 

142  Megohmetera 

143  Meters,  A.  C. 

144  Meters,  D.  C. 

145  Mica 

146  Mica  sheets 

147  Milliammeter* 

148  Mineral* 

149  Molded  insulation 

150  Molybdenum 

151  Mountings,  coil 

152  Mountings,      condenser 

153  Mountings,  end 

154  Mountings,  grid  leak 

155  Mountings,  honeycomb 
coil 

156  Mounting*,     Inductance 

157  Name  plate* 

15S  Neutrodyne  set  parts 

159  Nuts 

160  Ohmeter* 

161  Oscillators 

162  Panel  cutting  and  drilling 

163  Panels,     drilled    and    un- 
drilled 

164  Panels,  fibre 

165  Panels,  hard  rubber 

166  Parts 

167  Paste,  soldering 

168  Patent  attorney* 

169  Phone  connectors,  multi- 
ple 

170  Phonograph  adapters 

171  Plates,  condenser 

172  Plugs,  coil 

173  Plugs,  telephone 

174  Pointers,  dial  and  knob 

175  Poles,  aerial 

176  Potentiometer* 

177  Punching  machine* 

178  Reinartz  set  parts 

179  Regenerative  set  parts 

180  Receiver  caps 

181  Rectifiers,  battery 

182  Resistance  leaks 

183  Resistance  units 

184  Rheostat  base* 

185  Rheostat  strip* 


186  Rheostats,  automatic 

187  Rheostats,  battery 

188  Rheostats,  dial 

189  Rheostats,  filament 

190  Rheostats,     potentiometer 

191  Rheostats,  power 

192  Rheostats,  vernier 

193  Rods,  ground 

194  Rotor* 

195  Scrapers,  wire 

196  Screw  drivers 

197  Screws 

198  Schools,  radio 

199  Sets,  receiving — cabinet 

200  Sets,  receiving — crystal 

201  Sets,     receiving — knock 

202  Sets,     receiving  —  Neutro- 
dyne 

203  Sets,  receiving — portable 

204  Sets,   receiving — radio   fre- 
quency 

205  Sets,     receiving — reflex 

206  Sets,    receiving — regenera- 
tive 

207  Sets,    receiving — 'Reinartz 

208  Sets,  receiving — sectional 

209  Sets,  receiving — short  wave 

210  Sets,    receiving — super-re- 
generative 

211  Sets,  transmlttln* 

212  Slate 

213  Shellac 

214  Sliders 

215  Socket  adapter* 

216  Socket*. 

217  Solder 

218  Soldering  Irons,  electric 

219  Soldering  paste 

220  Solder  flux 

221  Solder  salt* 

222  Solder  solution 

223  Spaghetti  tubln* 

224  Spark  coils 

225  Spark  gaps 

226  Stamping* 

227  Stators 

228  Stop  points 

229  Switch  arm* 

230  Switch  levers 

231  Switch  points 

232  Switch  stops 

233  Switches,  aerial 

234  Switches,  battery 

235  Switches,  filament 

236  Switches,  ground 

237  Switches,  inductance 

238  Switches,  panel 

239  Switches,  single  and  dou- 
ble throw 

240  Tone  wheels 

241  Towers,  aerial 

242  Transformers,     audio    fre- 
quency 

243  Transformers,  filament 

244  Transformers,  modulation 

245  Transformers,  power 

246  Transformers,  push-pull 

247  Transformers,     radio     fre- 
quency 

248  Transformers,  variable 

249  Transmitter* 

250  Tubes,  vaccuum — peanut 

251  Tubes,   vacuum — two   ele- 

252  Tubes,  vacuum — -three  ele- 
ment 

253  Tuner* 

254  Variocoupler*.  hard  rubber 

255  Variocouplers.  molded 

256  Variocouplers,  wooden 

257  Variometers,  hard  rubber 

258  Variometers,  molded 

259  Variometers,  wooden 

260  Varnish,  insulatin* 

261  Voltmeters 

262  Washers 

263  Wave  meters 

264  Wave  traps 

265  Wire,  aerial 

266  Wire.'braided  and  stranded 

267  Wire,  copper 

268  Wire,  insulated 

269  Wire,  Litx 

270  Wire,  magnet 

271  Wire,  platinum 

272  Wire,  tungsten 


I        1       1        I       1       I 


I        I        I        I        I 


I  am  a —  Q  Dealer  [J  Jobber 

Firm     [If  identified  with  Radio  industry] 

My   Occupation  

My   Nam*   

AddroH — — __ 

City   .'. 


]    Mfgrs.'  Rep.  □    Manufacturer 


RADIO  AGE  BUYERS'  SERVICE,  600  N.  Dearborn  St.,  Chicago,  111. 

Please  Bee  that  I  am  Bupnlied  with  buying  specifications  and  prices  on  the  articles  numbered  herewith: 


(11-25) 


,    State   . 

*     Tested  and  Avvroved  by  RADIO  AGE 


The  Magazine  of  the  Hour 

A  New    Idea  in  Community 
Broadcasting 

WHAT'S  going  to  happen  when  every 
enterprising  community  from  Sauk 
Center  to  Kamchatka  puts  up  a  radio 
broadcasting  station  to  invite  a  travel 
hungry  world  to  come  and  bask  in  the 
glow  of  the  rainbow's  end,  sample  the 
pot  of  gold  and  bathe  in  the  fountain  of 
youth? 

That  question  probably  has  occurred 
to  most  of  us  who  have  watched  and 
listened  through  the  period  of  experimen- 
tation with  radio  as  a  medium  for  com- 
munity advertising. 

What  about  the  answer? 
Well,  if  you'll  watch  and  listen  as  care- 
fully in  the  future  as  you  have  done  in  the 
past,  you  will  see  the  question  will  never 
have  to  be  answered  because  the  condition 
of  affairs  outlined  above  will  never  quite 
come  to  pass.  We  may  get  pretty  close  to 
it  before  the  full  lesson  is  learned, 
but  long  before  the  time  when  the 
prospective  pleasure-seeker,  the  would-be 
home-seeker,  and  the  yearning  health- 
seeker  would  be  carted  off  kicking  and 
screaming  to  the  nearest  asylum,  the 
community  radio  broadcasting  outfits 
will  have  awakened  to  a  true  appreciation 
of  their  earlier  indiscretions. 

Then,  instead  of  being  puzzled  and 
bored  and  harassed  about  where  lies  our 
future  health  and  happiness,  profit  and 
pleasure,  we'll  begin  to  be  really  enter- 
tained, amused  and  informed  through  the 
medium  of  the  municipal  radio  broad- 
casting station. 

When  it  comes  to  advertising,  radio  is 
being  employed  with  skill  and  science. 
Programs  entertain,  amuse  and  inform 
people — tell  them  what  they  want  to 
know,  present  to  them  sounds  and  sights 
and  sensations  that  are  pleasant.  Radio 
is  properly  used  as  a  good-will  builder 
rather  than  a  direct  sales  medium. 

The  school  of  municipal  radio  broad- 
casting is  beginning  also  to  learn  this 
valuable  lesson.  Witness,  for  instance, 
the  case  of  Jacksonville,  Florida.  Here  is 
a  city  that  is  erecting  a  broadcasting 
station  as  a  project  of  the  city  government 
to  entertain,  amuse  and  educate  its  own 
people  and  those  within  hearing  of  the 
station. 

Of  course  Jacksonville  expects  this 
radio  station  to  help  advertise  Jackson- 
ville. As  a  matter  of  fact  it  expects  the 
station  to  play  a  very  substantial  part  in 
the  program  of  telling  the  world  things  it 
will  be  pleased  to  know  about  Jacksonville 
and  her  opportunities  and  advantages  as 
a  port,  an  industrial  center,  a  distributing 
point  in  one  of  the  most  rapidly  growing 
consuming  centers  of  the  country,  the 
center  of  a  famous  agricultural  territory 
and  a  resort  city  of  unusual  advantages 
and  facilities.  But  the  methods  by  which 
the  municipal  radio  broadcasting  station 
will  accomplish  its  part  of  the  program  of 
advertising  Jacksonville  to  the  outside 
world,  will  be  the  most  improved,  the 
most  up-to-date  methods.  It  will  be 
painless.  Nay,  more,  it  will  be_ really 
pleasurable.  For  Jacksonville  is  de- 
termined that  her  municipal  radio  broad- 
casting venture  shall  reap  for  her  a 
harvest  of  friends,  visitors,  and  new 
citizens. 


¥ 


Howling  and  distortion  in  radio  sets  is  frequently 
caused  by  running  transformer  leads  too  close  to- 
gether. 

The  case  and  brackets  on  B-T  Euphonic  Trans- 
formers are  so  designed  that  the  transformer  may  be 
mounted  in  any  position, — base-board,  sub  panel,  or 
side, — with  terminals  always  in  position  for  most 
convenient  and  efficient  wiring. 

This  is  exclusively  a  feature  of  the  B-T  Euphonic 
Transformer. 


1  'Pleasing  to  the  Ear' ' 

More  and  more  is  popular  judgment  of  radio  directed  toward  quality.  Fidelity  to 
speech  or  music  as  given  in  the  studio  is  the  requirement  of  today. 

Convinced  that  better  audio  transformers  were  necessary  to  secure  the  full  benefit 
of  B-T  circuits  and  apparatus,  B-T  engineers  tackled  the  transformer  problem.  The 
result  of  their  long  effort  is  the  B-T  Euphonic,  a  superior  transformer.  As  its  name  im- 
plies, it  is  "Pleasing  to  the  Ear."  We  believe  it  the  best  audio  transformer  available  today. 

Ratio  2.2  to  1  Price     $5.00  Ratio  4.7  to  1  Price      $5.75 


B-T  Straight  Line  Frequency 
Condenser 

All  the  solid  dependability  of 
the  famous  B-T  "Lifetime"  Con- 
denser,— the  same  electrical  ef- 
ficiency, the  same  superior  bearing 
construction, — now  available  in 
straight  line  frequency  plate 
design.  For  those  who  prefer  this 
type. 

Send  for  circulars. 

Two  Condensers,  but  One  Dial 
Control 


B-T  Torostyle  Transformer 

Built  properly  the  toroid  in- 
ductance is  a  big  improvement. 
Poorly  designed,  a  toroid  makes 
oscillation  control  difficult  and 
tuning  broad. 

B-T  Torostyle  Transformers  are 
the  result  of  inductance  experience 
that  began  before  broadcasting. 

The  Torostyle  is  built  right. 

Send  for  complete  information. 

Used  in  New  Circuits 

New  circuits  require  potentio- 
meters and  variable  high  re- 
sistances. Tone  is  often  improved 
by  using  a  modulator.  B-T  Re- 
sistances are  stepless,  non  induc- 
tive, smooth  in  operation  and  are 
unaffected  by  continued  service. 

Literature  on  request. 

The  B-T  Universal  Socket 


The  famous  B-T  Type  L  Con- 
denser now  available  in  tandem. 
A  typically  sensible  "trimming" 
device  enables  accurate  balance 
between  units. 

Literature  on  request. 

Tuning  is  Easier 

Distance  and  tone  are  often 
only  a  matter  of  accurate  adjust- 
ment. B-T  Tuning  Controls 
permit  hairline  adjustment  easily 
and  quickly. 

Improve  the  appearance  of  your 
set  as  well. 

Circulars  on  request. 

The  Latest  Thing  in  Radio 

The  latest  best  circuits,  the  newest  apparatus  are  always  in  "Better 

Tuning."  Helpful  hints  to  set  owners  make  it  worth  ten  times  the  price. 

Send  1 0  cents  for  your  copy. 


A  socket  that  takes  the  Navy 
Base  Tubes  all  the  New  UX 
tubes  without  an  adaptor.  Poor 
contact  an  impossibility.  Less 
capacity  due  to  small  area  and 
wide  separation  of  contact  springs. 

Send  for  circulars. 


* 


Bremer-Tully  Mfg.  Co. 


532  S.  Canal  Street,  Chicago,  Illinois 


*      Tested  and  Approved  by  RADIO  AGE     * 


Zenith  was  created  for  the  home 


LL  one  needs  to  get  the  fin- 
est radio  results  from  Super- 
Zenith  is  good  musical  taste 
and  a  feeling  for  exquisite 
tonal  values. 

So  far  as  technical  ability  is  con- 
cerned, the  Super-Zenith  is  so 
easily  controlled  that  a  child  can 
bring  in  just  as  many  stations — 
just  as  quickly — each  with  the 
same  clear  quality  of  tone — as  a 
radio  engineer. 

Only  a  demonstration  can  make 
completely  evident  the  remark- 
ably selective  character  of  the  Su- 
per-Zenith— its  clear,  sweet  tone 
— its  thorough  dependability. 

Such  a  demonstration  is  yours 
for  the  asking — in  your  own 
home,  if  you  so  desire.  Simply 
telephone  your  nearest  dealer. 


Again  Commander  Donald  B.  MacMillan  chooses 
Zenith  for  his  Arctic  Expedition.  When  human  lives 
may  depend  upon  the  reliability  of  radio  perform- 
ance, only  one  reason  can  explain  his  choice:  Zenith 
has  proved  to  be  the  best  obtainable  at  any  price. 


*t2* 


Super-Zeniths  are  priced  at  from  $240 
to  $2,000.  Each  instrument  is  sold 
under  a  quality  guarantee.  Above 
is  shown  the  De  Luxe  Spanish  model. 


Super-Zenith  VII  .  .  $240 
Super-Zenith  VIII  .  .  260 
Super-Zenith  IX  .  .  .     355 

Also  Zenith  regenerative  sets  (non- 
radiating)  licensed  under  Armstrong 
U.  S.  Patent  No.  1,113,149 


* 


Zenith  4R 
Zenith  3R 


$100 
175 


Zenith  Radio  Corporation,  Straus  Building,  Chicago,  III. 


^LONC    DISTANCE- 

TRADE     MARK     REQ, 


Blueprint  Section  Every  Month 


Me  Marine  of  the  Hour 


W 


m 


\^<%*j 


W> 


v*S-i 


W 


\m 


4 


WA    ■?}>■ 


December 

19^5 


w 


Radio  Age  Model  Receiver 

/n  this  Issue 


SILVER 
SIX 


S-M  .00035  SLF 
CONDENSERS 

have  been  chosen  for 
the  new  Radio  Age 
Receiver.  Get  them 
from  your  Dealer. 


FACTS 

THE  "WHY  OF  THE  SIX" 

as    described  in  Radio  Broadcast  of    November 
and  December 

SELECTIVITY  is  such  that  out  of  town  stations 
may  be  brought  to  Chicago  through  twelve  powerful 
local  stations.  Selectivity  can  be  regulated  at  will, 
from  a  degree  satisfactory  for  ordinary  reception, 
up  to  the  surprising  limit  where  side-bands  are  cut. 
SENSITIVITY  is  so  great  that  nothing  will  sur- 
pass the  "Six"  except  special  laboratory-built 
super-heterodynes.  Either  coast  may  be  brought 
in  to  Chicago  during  the  summer  months  on  a  small 
antenna — in  many  cases  on  a  loop. 
FLEXIBILITY  permits  the  use  of  antenna  or 
loop  with  either  detector,  one  or  bcth  stages  of 
radio  frequency  amplification.  Interchangeable 
R.  F.  Transformers,  with  adjustable  antenna  coup- 
ler, permit  operation  on  all  waves  from  50  to  550 — 
or  higher  if  desired. 

VOLUME  is  so  great  as  to  paralyze  any  but  the 
best  loud-speakers.  Yet  it  may  be  adjusted  to  any 
degree  by  a  single  knob. 

QUALITY  cannot  be  excelled  due  to  resistance 
coupled  amplification.  It  is  the  only  receiver  that 
will  bring  real  appreciation  of  "cone"  speakers. 
CIRCUIT  consists  of  two  stages  of  R.  F.  amplifi- 
cation with  special  oscillation  control  uniformly 
effective  at  all  wavelengths,  grid-biased  detector 
and  three  stage  resistance  coupled  audio  amplifier. 
EASE  OF  CONTROL  allows  use  of  one,  two  or 
three  dials  at  will. 

TUBES  may  be  either  dry  cell  or  storage  battery, 
with  UV201- A's  recommended.  ('B"  Battery 
Consumption  at  135  volts  is  below  10  miliamperes — 
less  than  one-third  that  of  other  six-tube  receivers. 
ASSEMBLY  requires  but  a  few  hours,  using  only 
parts  supplied  in  kit. 


Mail  this  Coupon 

Silver-Marshall,    Inc.,    Chicago,    III. 

Gentlemen:    Please  send  me: 

A — Complete  building  data  on  the  Silver  "Six," 

for  which  I  am  enclosing  50c. 
B— Descriptive  circulars  on  S-M  Products. 


claims  vs.  PRAISE 


1 


The  new  "Six"  by 
McMurdo  Silver 
lays  claim  to  a 
marvelous  selectiv- 
ity— an  uncanny 
ease  of  control — a 
tone  quality  be- 
yond belief — sen- 
sitivity that  makes 
DX  work  fascinat- 
ing— volume  more 
than  sufficient. 
Here  you  have  the 
reports  of  two 
builders  who  were 
among  the  first  to 
buy  Silver  Six  Kits. 
The  claims  are  jus- 
tified. 


from  a  Haberdasher 

Mr.  L.  H.  STREETER,  Chicago,   III. 

"Two     weeks    ago     I     purchased    your 
'  Silver    Six'     Kit     .      .      .      constructed 
it   easily    and   quickly     .      .      .     logged 
seventeen  out  of  town  stations  Tuesday 
evening  through  Chicago  locals 
only     one     mile     from      WQJ 
KOA  comes  in  at  40,  WSAI  at  40   1-2 
and    WLS   at   41    1-2      ..      .      able   to 
separate     each.      Recommend     Six     for 
ease     of    tuning     and     volume 
wrecked    a    small    cone    speaker    with 

volume   from   local   station 

Sure  is  a  wonder!" 

from  an  Auditor 

Mr.  V.  H.  PLENGE,  Chicago,  lit. 

"Your     'Six'     gets     wonderful     results 

nothing    to    outperform    it. 

Second    station    I    got   was    KOA 

on  Monday  logged  21  stations 

with  clarity  and  volume  equal  to  locals 

found  set  extremely  simple  to 

wire     .      .      .     completed  job  in  3  hours 

.     ..      .      Six    has    a    fine    tone    and    an 

unusual  degree  of  selectivity." 


Type   600   Kit  including  all  parts  necessary   to   build     flju'3     00 
the  complete   "Six" *p\J*J  »\J 

Type  610  Kit,  essentials  only,  including  3   condensers,     t!  /  /      /     i 

3   inductances  and  3  inductance  sockets. _ *y4*£    •/  w 

See  These  and  Other  S-M  Products  at  Your  De"'<"-S 

Silver-Marshall, 

114  SouthWabash  Avenue 
CHICAGO 


*      Tested  and  Approved  by  RADIO  AGE     * 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


Earn  v50  to  '200  a  Week 

in  RADIO 


You  can !  Hundreds  of  ambitious  men  are  already 
earning  thousands  of  dollars  in  this  wonderful 
new  industry — you,  too,  can  get  your  share. 
Mail  coupon  below  for  Free  Book  which  describes 
fully  the  amazing  money-making  opportunities 
in  Radio  and  tells  you  how  YOU  can  earn  from 
$5,000  to  $10,000  a  year. 


THE  astounding  growth  of  Radio 
has  created  thousands  of  big 
money  opportunities.  Millions  of 
dollars  were  spent  during  the  past 
year  on  Radio,  and  thousands  of 
young  men  are  needed  right  now  to 
meet  the  ever-increasing  demand  of 
work. 

Men  are  needed  to  build,  sell  and 
install  Radio  sets — to  design,  test, 
r  e  p  a  i  r — as  Radio  engineers  and 
executives — as  operators  at  land 
stations  and  on  ships  traveling  the 
world  over — as  operators  at  the 
hundreds  of  broadcasting  stations. 
And  these  are  just  a  few  of  the  won- 
derful opportunities. 

Easy  to  Learn  Radio  at 
Home  in  Spare  Time 

No  matter  if  you  know  nothing 
about  Radio  now,  you  can  quickly 
become  a  Radio  Expert,  by  our  mar- 
velous new  method  of  practical  in- 
struction— i  nstruction  which 
includes  all  the  material  for  building 
the  latest  up-to-date  Receiving  Sets. 

Scores  of  young  men  who  have 
taken  our  course  are  already  earning 


PAY  INCREASES  OVER  $100  A 
MONTH 

I  am  averaging  anywhere  froni  S75 
to  S150  a  month  more  than  I  was 
making  before  enrolling  tvith  you.  I 
would  not  consider  810,000  too  much 
for  the  course. 

(Signed)      A.  N.  LONG. 

Greensburg.  Pa. 


DOUBLES  SALARY 

I  can  very  easily  make  double  the 
amount  of  money  now  than  before  I 
enrolled  with  you.  Your  course  has 
benefited  me  approximately  83,000 
over  and  above  what  I  would  have 
earned  had  I  not  taken  it. 

T.  WINDER. 
Grand  Junction.  Colo 


FROM  $15  TO  $80  A  WEEK 
Before  I  enrolled  with  J-ou  I  was 
making  S15  a  week  on  a  farm.  Now 
I  earn  from  82,080  to  84.420  a  year, 
and  the  work  is  a  hundred  times 
easier  than  before.  Since  graduating 
a  little  over  a  year  ago,  I  have  earned 
almost  S4.000,  and  I  believe  the  course 
will  be  worth  at  least  8100.000  to  me. 
(Signed)     GEO.  A.  ADAMS, 

Tamaqua,  Pa. 


from  $75  to  $200  a  week.  Merle 
Wetzel  of  Chicago  Heights,  111.,  ad- 
vanced from  lineman  to  Radio  En- 
gineer, increasing  his  salary  100% 
even  "while  taking  our  course!  Emmet 
Welch,  right  after  finishing  his  train- 
ing, started  earning  $300  a  month 
and  expenses.  Another  graduate  is 
now  an  operator  of  a  broadcasting 
station — PWX  of  Havana,  Cuba — 
and  earns  $250  a  month.  Still 
another  graduate,  only  16  years  old, 
is  averaging  $70  a  week  in  a  Radio 
store. 

Wonderful  Opportunities 

Hardly  a  day  goes  by  without 
our  receiving  urgent  calls  for  our 
graduates.  "We  need  the  services 
of  a  competent  Radio  Engineer." 
"We  want  men  with  executive  abil- 
ity in  addition  to  Radio  knowledge 
to  become  our  local  managers." 
"We  require  the  services  of  several 
resident  demonstrators" — these  are 
just  a  few  small  indications  of  the 
great  variety  of  opportunities  open 
to  our  graduates. 

Take  advantage  of  our  practical 
training  and  the  unusual  conditions 
in  Radio  to  step  into  a  big  paying 
position  in  this  wonderful  new  field. 
Radio  offers  you  more  money  than 
you  probably  ever  dreamed  possible 
— fascinating,  easy  work — a  chance 
to  travel  and  see  the  world  if  you 
care  to,  or  to  take  any  one  of  the 
many  Radio  positions  all  around  you 
at  home.  And  Radio  offers  you  a 
glorious  future! 

The  National  Radio  Institute  is 
America's  Pioneer  Radio  Home- 
Study  Schools-established  in  1914. 
Our  course  is  an  absolutely  complete 
one  which  qualifies  for  a  govern- 
ment first-class  commercial  license. 
It  trains  you  for  bigger  paying  jobs 
in  Radio. 

*    Tested  and  Approved   by  RADIO  AGE    # 


Send   for 
FREE  RADIO  BOOK 

Learn  more  about  this  tremendous  new  field  and 
its  remarkable  opportunities.  Learn  how  you  can 
quickly  become  a  Radio  Expert  and  make  big  money 
in  Radio. 

We  have  just  prepared  a  new  48-page  book 
which  gives  a  thorough  outline  of  the  field  of  Radio — 
and  describes  our  amazing,  practical  training  in 
detail.  This  Free  Book,  "Rich  Rewards  in  Radio." 
will  be  sent  to  you  without  the  slightest  obligation. 
Mail  coupon  for  it  jioivI 

For  a  short  time  we  are  offering  a  reduced  rate 
to  those  who  enroll  at  once.  Act  promptly  and  save 
money. 


National 

Radio 

Institute 


Dept.   53-OB 

Washington, 
D.  C. 


NATIONAL  RADIO  INSTITUTE, 
Dept.  53-OB,  Washington,  D.  C. 

Please  send  me  without  the  slightest  obligation 
your  Free  Book,  "Rich  Rewards  in  Radio."  and 
full  details  of  your  Special  Free  Employment  Service. 
Please  write  plainly. 


City.. 


RADIO  AGE /or  December,  1925 


The  Magazine  of  the  Hour 


The  Magazine  of  the  Hour 

Established  March,  1922 


Volume  4 


December,  1925 


Number  12 


CONTENTS 

Cover  Design  by  Anker  P.  Mehlum 

Radio  Age  Model  Receiver - 7 

By  the  Technical  Staff 

A  Receiver  that  Employs  Inductive  Gang  Control... .15 
By  H.  Frank  Hopkins 

Making  Radio  for  Quality _...17 

By  S.  R.  Winters 

Tuned  R.  F.  and  Regeneration. 19 

By  Brainard  Foote 

Tuning  with  Chart  Curves.. 21 

By  Bertram  C.  Rogers 

More  Pictures  of  Models  at  the  Radio  Show 22-23 

What  Constitutes  a  Good  Variable  Condenser .24 

Back  from  the  Arctic 25 

What   the    Broadcasters   Are   Doing.      Feature 
Section ...28-38 

RADIO  AGE  Blueprint  Section— A  3  Tube  In- 
ductive Coupled  Feedback  Receiver ..39-46 

By  John  B.  Rathbun 

Pickups  and  Hookups  by  Our  Reader. 47 

Corrected  List  of  Broadcasting  Stations .66,  68,  70 


Radio  Age  is  published  monthly  by  RADIO  AGE,  Inc. 
Member:     Audit  Bureau  of  Circulations. 


Publication  Office,      Mount    Morris,    111. 

404  North  Wesley  Ave., 

Address  all  communications  to  RADIO  AGE,  Inc. 

Executive,  Editorial  and  Advertising  Offices 

500  N.   Dearborn  Street,  Chicago,   111. 


Frederick  A.  Smith,  Editor 
F.  A.  Hill,  Associate  Editor 
Frank  D.  Pearne,  Technical  Editor 
M.  B.  Smith,  Business  Manager 


Advertising  Director 
HARRY  A.  ACKERBURG 

500  N.  Dearborn  St.,  Chicago,  III. 


Eastern  Representative 
DAVIDSON  &   HEVEY,   17  West  42nd  St.,   New  York  City 

Pacific  Coast  Representative 

V.   M.   DEPUTY  &  ASSOCIATES,   515  F.  W.  Braun  Bldg., 

Los  Angeles,  Cal. 


Final  Advertising  forms  close  on  the  20th  of  the  2nd  month 
preceding  date  of  issue 

Vol.  4,  No.  12.    Issued  monthly.    Subscription  price  $2.50  ayear.    December,  1925. 

Entered  as  second-class  matter  at  post  office  at  Mount  Morris,  Illinois,  under  the 

Act  of  March  3,  1879. 


Copyright.  1SS5,  by  RADIO  AGE,  In 


A  Chat  With 
the  Editor 

IT  IS  noteworthy  that,  in  pre- 
senting our  Radio  Age  Model 
Receiver,  Type  H,  in  this 
issue,  we  are  not  claiming  that  it 
will  set  the  technical  world  afire. 
It  is  not  revolutionary,  hot  radi- 
cally different.  But  we  do  claim 
that  it  is  a  good  circuit  and  that 
it  is  well  worth  the  while  of  the 
set-builder  to  build  one  like  it. 
We  also  believe  we  have  presented 
the  instructions  and  blueprints, 
drawings  and  photographs  in  such 
a  manner  that  the  experimenter 
can  build  the  receiver  with  a 
minimum  of  time  and  trouble. 
Our  technical  staff  has  constructed, 
tested  and  proved  the  circuit  and 
you  may  assemble  it  with  assur- 
ance that  it  will  give  you  distance, 
volume  and  a  pleasurable  degree  of 
selectivity. 

We  foresee,  however,  that  some 
readers  will  hail  one  or  two  ele- 
ments of  this  receiver  with  enthu- 
siasm. For  example  the  owner  of  a 
neutrodyne,  by  studying  this  hook- 
up will  find  a  way  of  changing 
coils  in  his  set  that  will  enable 
him  to  get  better  results  without 
feedback,  insuring  maximum  am- 
plification over  practically  the  en- 
tire American  wave  band.  The 
circuit  also  makes  use  of  twin 
resistances  restricting  the  plate 
voltages  to  prevent  undesired  oscil- 
lation. 

Another  type  of  the  Radio  Age 
Model  Receiver  will  be  described 
in  complete  detail  in  the  January 
issue  of  this  magazine.  Progress 
already  made  with  this  model, 
which  we  are  calling  "Type  HX" 
indicates  that  it  will  thoroughly 
satisfy  the  ambitions  of  the  set- 
builder  who  wants  performance 
and  quality  in  his  home-built  set. 
There  will  be  other  types  in 
later  issues. 

We  suggest  particularly  that 
you  do  not  miss  the  January  issue. 
It  is  our  honest  belief  that  it  will 
be  a  liberal  education  in  set- 
construction  to  any  fan  who  follows 
these  types  of  the  Model  Receiver 
as  they  are  developed  from  month 
to  month. 

Editor  of  RADIO  AGE 


RADIO  AGE  for  December,  192 


For  radio  economy 


Eveready  Radio  Batteries  are  noted  for  their  long 
service  and  economical  operation.  They  are  made  in 
different  sizes  and  types  so  that  every  radio  user  can 
enjoy  the  economy  and  convenience  to  be  had  by 
fitting  exactly  the  right  Eveready  to  his  receiver. 
The  five  dry  cell  types  of  Eveready  Radio  Batteries 
are  here  illustrated  and  described  to  make  it  easy 
for  you  to  decide  just  which  will  give  the  longest 
and  most  economical  service  on  your  set.  A  dealer 
near  you  sells  Evereadys. 

Eveready  Heavy-duty  "B"  Battery  for  four 
or  more  tubes 
No.    486.      Extra-large    Layerbih.      45    volts.      Vertical. 
Eveready's  latest  contribution  to  rauio.   The  new  Layerbih 
construction    which    gives    much    greater    service.      Same 
size  as  No.  770.    Price  $5.50. 

Eveready  "B"  Battery  for  one  to  three  tube  sets 
No.  779.   Large.   22^  volts.   Vertical.    Especially  adapted 
for  Radiola  25,   DeForest   D-17   and   Operadio   receivers. 
Same  capacity  as  No.  766,  and  suitable  wherever  variable 
taps  are  not  required.    Price  $2.00. 

Eveready  "B"  Battery  for  portable  sets 
No.  764.     Portable.     22J4   volts.     Vertical.     For  portable 
sets    where    medium    weight    and    size    are    permissible. 
Price  $1.75. 

Eveready  "A"  Battery 
Eveready  Columbia  Ignitor  Dry  Cell  Radio  "A"  Battery 
for  all  dry-cell  tubes.     V/z  volts.     The  dry  battery  used 
by  vacuum-tube  engineers  in  developing  the  dry-cell  tube. 

Eveready  " C"  Battery 
No.  771.     4^<  volts.     Saves  "B"  Batteries,  improves  tone. 
Price   60  cents. 

Manufactured  and  guaranteed  by 

NATIONAL  CARBON  COMPANY,  Inc. 
New  York  San  Francisco 

Canadian  National   Carbon   Co.,  Limited,  Toronto,   Ontario 


Radio  Batteries 

-they  last  longer 


It  'raja        JVsSe1"       ififefc. 


1< 


'mmm 


No.  486 
'    4S-v olt 
Layerbilt 
Extra- 
large 
Vertical 
Price 
$5.50 


:;S|l|fte|P 


wiftmS^tti^H1!^ 


fillli 


an 


¥    Tested  and,  Appri 


by   RADIO   AGE    # 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


MR.  W.  WITT  BURNHAM ,  head  of  the  Burndept 
Company,  London,  England,  manufacturers 
of  loud  speakers,  is  seeking  a  market  for  his 
goods  in  the  United  States.  For  this  reason  it  is 
puzzling  to  encounter  a  letter  written  by  Mr.  Burnham 
and  published  in  "The  Wireless  Trader,"  a  London 
periodical,  in  which  Mr.  Burnham  accuses  American 
manufacturers  of  "dumping"  inferior  radio  apparatus 
on  the  English  market.  The  letter  recites  what  pur- 
ports to  be  a  review  of  the  efforts  of  American  manufac- 
turers to  sell  their  last  season's  merchandise  in  the 
United  States  and  continues: 

"These  operations  proving  unsuccessful,  the  Ameri- 
can manufacturer  is  now  trying  to  unload  his  last  sea- 
son's stock  on  the  world;  to  make  room  for  his  1926 
models  which,  I  am  given  to  understand,  will  be  of 
entirely  different  patterns." 

The  point  that  puzzles  us  is  the  fact  that  Mr.  Burn- 
ham launches  such  a  general  attack  on  American 
manufacturers  simultaneously  with  his  effort  to  make 
friends  in  this  market.  Observe  his  candor  in  the 
closing  paragraph  of  his  letter: 

"Finally,  I  would  urge  your  readers  to  keep  the 
British  Wireless  Trade  in  British  hands.  Do  not  send 
unnecessary  dollars  to  America.  The  British  manu- 
facturers know  exactly  what  is  wanted  to  please  the 
British  public,  and  they  can  produce  enough — and 
some  to  spare." 

Mr.  Burnham's  views  are  to  be  accepted  as  represen- 
tative for  he  is  chairman  of  the  National  Association  of 
Radio  Manufacturers  and  Traders. 

The  editor  of  '  'The Wireless  Trader' '  readily  acquiese- 
esin  Mr.  Burnham's  request  that  his  letter  be-published. 
Going  a  step  further,  he  writes  an  editorial  indorsing 
Mr.  Burnham's  views  and  giving  them  even  stronger 
expression.    The  London  editor  says: 

"It  is  admitted  that  there  are  many  unique  points  of 
design  and  practice  in  American  apparatus;  but  these 
are  peculiarly  suited  to  reception  conditions  such  as 
those  which  obtain  in  the  United  States,  and  are  of 
extremely  little  use  in  Great  Britain.  Moreover,  so 
far  as  tone  quality  in  reception  is  concerned,  although 
there  is  still  room  for  improvement,  British  apparatus 
is  much  better  than  any  produced  in  America." 
The  editor  concludes  with  the  following  pragraph: 
"In  short,  it  is  an  irrefutable  fact  that  British  manu- 
factured apparatus  is  best  for  the  British  market. 
Therefore  do  not  be  deluded  by  the  big  talk  and  flashy 
productions." 

The  English  editor  reminds  his  readers  of  the  national 
slogan  "Buy  British  Goods."  We  have  no  quarrel  with 
the  editor  regarding  the  slogan.  We  believe  some- 
times that  Americans  would  do  well  to  adopt  a  similar 
slogan.  But  we  believe  even  British  readers  of  our 
magazine  will  agree  with  us  that  the  criticisms  in  the 
letter  of  Mr.  Burnham  and  in  the  editorial  of  the 
London  periodical  lose  much  of  their  force  because  of 
the  fact  that  they  are  so  sweeping  in  their  character. 
We  are  compelled  to  admit  many  American  receiving 
sets  would  not  work  well  on  the  higher  wave  lengths 
used  by  broadcasting  stations  in  the  British  Isles. 
But  neither  critic  makes  any  distinction  between  the 


American  sets  offered  lor  sale  in  England.  Neither  do 
they  exclude  American  parts  and  accessories  from 
their  attack. 

The  writer  of  this  editorial  has  spent  considerable 
time  in  England  and  in  Continental  Europe  making 
observations  of  broadcasting  conditions  and  radio 
apparatus  and  we  want  to  go  on  record  as  saying  that 
much  of  our  American  apparatus  compares  very 
favorably  with  that  manufacturered  abroad.  It  oc- 
curred to  us  that  American  receiving  sets  are  much 
more  simple  in  operation  and  fully  as  effective  in  re- 
sults as  those  we  saw  in  London.  The  gentlemen 
appear  to  have  erred  in  over-stating  their  case  and  in 
making  their  assertions  too  general. 

As  editor  of  an  American  radio  magazine  of  pronoun- 
ced technical  tendencies,  it  has  been  our  privilege  to 
personally  inspect  a  great  deal  of  radio  equipment 
produced  by  manufacturers  in  all  parts  of  the  United 
States.  We  have  taken  pride  in  the  universal  effort 
of  those  manufacturers  to  make  good  merchandise. 
We  have  marvelled  at  the  refinements  which  have  been 
added  to  these  products.  We  have  not  been  surprised 
at  reading  the  official  figures  on  the  increase  of  our 
export  business.  It  has  not  escaped  our  attention  that 
American  radio  goods  are  finding  an  encouraging  re- 
ception in  Canada  and  Australia.  There  may  be  un- 
scrupulous manufacturers  who  are  trying  to  "dump" 
inferior  stuff  on  English  markets  but  we  know  of  many 
important  American  manufacturers  who  are  building 
parts  and  accessories  on  sheer  merit  and  who  are  trying 
to  merchandise  them  abroad  without  apology  or  the 
necessity  of  apologizing.  We  know  of  an  English 
loud  speaker  that  is  really  good  and  which  is  being 
sold  in  America.  We  believe  that  several  American 
loud  speakers  surpass  this  English  instrument  in  qua- 
lity of  performance.  But  it  would  scarcely  occur  to  us 
to  make  that  fact  the  basis  for  an  appeal  to  our  readers 
to  boycott  English  goods. 

THIS  number  of  RADIO  AGE  finds  us  at  the  close 
of  our  fourth  year  in  the  radio  publication  field. 
It  is  pleasing  to  us  to  be  able  to  announce  that  this 
last  issue  of  1925  has  by  far  the  biggest  press  run  in 
our  history. 

THERE  are  still  many  individuals  who  believe  that 
newspapers  have  difficulty  in  finding  a  sufficient 
number  of  news  items  to  "fill  up."  Editors,  on  the 
contrary,  will  tell  you  they  throw  away  vastly  more 
news  than  they  print.  They  could  publish  many 
more  pages  of  news  and  still  have  a  reserve  supply. 
But  the  quality  of  the  newspaper  would  suffer  from  its 
lack  of  editorial  selection  and  condensation.  Could 
not  many  broadcast  stations  take  a  leaf  from  the  edi- 
tor's book?  Would  it  not  be  better  to  broadcast  only 
what  was  excellent  than  to  establish  an  arbitrary 
period  of  time  and  set  about  filling  that  period  at  the 
expense  of  selection  and  condensation?  The  question 
as  to  whether  there  are  too  many  broadcasting  stations 
is  open  to  argument.  That  many  broadcasting  stations 
do  entirely  too  much  broadcasting  is  not  open  to 
argument. 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour  5 


m 

n 

■ 

Zi   m 

■i 

RHv 

Hn 

'  §9 

Mi 

f..  .... 

^    I 


Imagine  a  Radio  Set 
stripped  of  these  parts 


What  a  useless  collection  of 
wood,  wire  and  metal  it  would 
be.  Realizing  that  the  parts,  and 
accessories  shown  here  are  whol- 
ly or  partly  of  Bakelite,  gives 
you  a  vivid  picture  of  its  impor- 
tance to  Radio. 

Today  Bakelite  is  used  in  a 
greater  variety  of  radio  parts 
than  ever  before — and  the  num- 
ber grows  constantly.  This 
dominance  of  Bakelite  in  radio 


reflects  the  experience  and  the 
opinions  of  radio  manufacturers, 
great  and  small. 

Radio  set  and  parts  manu- 
facturers have  every  facility  for 
testing  all  insulation  materials 
and  over  95%  have  standardized 
on  Bakelite.  This  indicates  how 
really  important  it  is  for  you  to 
make  sure  that  the  set  or  parts 
that  you  buy  are  Bakelite  in- 
sulated. 


* 


Write  for  Booklet  31 
BAKELITE   CORPORATION 

247  Park  Avenue,  New  York,  N.  Y. 
Chicago   Office:  636  West  2 2d  St. 


-> 


Bakelite  i3  an  occlusive 
trade  mark  and  can  be 
used  only  on  products 
made  from  materials 
manufactured  by  the 
Bakelite  Corporation. 
It  is  the  only  material 
which  may  bear  this 
famous  mark  of  excel- 
lence. 


\&£) 

BAKELITE 

is  the  registered  trade 
mark   for   the  phenol 
resin   product    manu- 
factured  under    pat- 
ents  owned   by  the 
Bakelite  Corporation. 

|      ■■■.■  .■  .--    .  ■-■■...•:j      :.■■■■•:.-          '    '       ■ 

I  i      i 

THE    MATERIAL    OF  A  THOUSAND    USES 


Tested  mid  Avoroned-  by  RADIO   AGE    * 


RADIO  AGE  for  December,  192: 


The  Magazine  of  the  Hoi.i 


Ozarka  Senior  Console— $197.50  &3SL 

Complete  with  Tubes,  Batteries  and  Speaker 


If  Your  Radio  is  Bought  Right 

It  Will  be  a  Life-Long  Pal 


A  LITTLE  more  time,  a  little  more  care  in  making  the 
selection  in  the  first  place  generally  tends  to  more 
lasting  satisfaction. 


Out  of  every  100  Ozarka's  sold  in 
1922  only  eight  are  not  today  in  the 
hands  of  the  original  owners — this 
does  not  include  1 7  out  of  each  1 00 
who  have  purchased  later  Ozarka 
models  in  newer  type  cabinets.  If 
there  is  a  single  Ozarka  that  is  not  in 
active  service  today,  we  have  never 
heard  of  it. 

Without  the  Ozarka  Service  in 
charge  of  direct  factory  trained  repre- 
sentatives, such  a  record  would  not  be 
possible.  Ozarka  service  can  be  had 
today  in  almost  every  country.  Pur- 
chasers in  South  Africa,  Alaska,  Swe- 
den, Newfoundland,  New  Zealand, 
and  Japan  all  receive  the  same  prac- 
tical service  as  those  in  Canada,  United 
States,  Mexico  and  Cuba.  Whenever 
you  find  the  sign  of  the  Ozarka  long 
distance  goose,  you'll  find  a  man  who 
knows  Ozarka  instruments  perfectly. 

If  such  service  added  more  to  your 
cost  price  it  might  be  a  matter  to  con- 
sider, but  it  doesn't.  Quality  for  quality 
you'll  find  Ozarka  prices  lower — four 
tube  Ozarka's  with  built-in  loud 


speakers  retail  for  $58.00 — five  tube 
with  built-in  speaker  $64.00,  up  to 
solid  walnut  console  design,  $160.50. 

Our  nearest  representative  will 
gladly  set  up  an  Ozarka  in  your  home, 
without  any  obligation  whatever.  He 
won't  tell  you  what  it  will  do — he  will 
let  you  do  all  the  tuning.  With  the 
Ozarka  you  must  satisfy  yourself,  as 
to  distance,  tone,  volume,  ease  of 
tuning  and  selectivity. 

More  than  this  you  will  be  very 
agreeably  surprised  at  Ozarka  prices 
— selling  as  we  do,  thru  our  own  direct 
factory  representatives,  our  selling 
expense  is  very  low — we  give  Ozarka 
purchasers  the  benefit  of  it. 

Where  is  there  a  value  to  compare 
with  the  one  shown  above  —  solid 
walnut  cabinet  (no  walnut  finish  or 
veneer) ,  imported  English  loud  speaker 
of  a  marvelous  tone,  five  tube  instru- 
ment with  75  ampere  Exide  storage 
battery,  90  volts  of  Eveready  "B" 
battery,  5  tubes,  aerial  equipment  all 
erected  and  the  price  is  only  $197.50. 


A  Few  More  Men 

are  Needed  to 

Sell  Ozarka 

In  a  great  many  counties  we  have  the 
man  we  want.  He  is  rapidly  building  up  a 
permanent  and  profitable  business  of  his 
own  because  he  has  an  instrument  that  will 
more  than  meet  all  competition.  More  than 
this,  he  is  trained  to  back  up  his  sales  with 
the  kind  of  service  that  counts. 

Many  well  established  Ozarka  representa- 
tives started  by  giving  us  only  their  spare 
time — their  evenings.  If  your  county  is  open 
you  can  do  the  same. 

The  investment  in  cash  is  very  small. 
The  investment  in  time  necessary  for  study 
is  considerable.  It  requires  patience,  but 
the  results  have  enabled  many  men  to  get 
out    of    the   salary   and    time   clock   class. 

Any  previous  sales  experience  is  helpful 
but  not  necessary.  We  can  and  will  teach 
you  how  to  sell. 

Send  for  84  Page  Book — 

"The  Ozarka  Plan" 

This  book  is  entirely  too  expen- 
sive to  be  sent  out  on  postal  card 
requests.  It  will  be  sent  FREE  to 
any  man  who  mails  the  coupon 
below  and  who  is  really  anxious 
to  improve  his  condition.  Tell  us 
about  yourself — ask  for  Ozarka 
Plan  No.  1 00  and  don't  fail  to  give 
the  name  of  your  county. 


02AHKft 


122  Austin  Avenue  A 
Chicago,  Illinois 


Gentlemen:  Without  obligation  send  book  "Ozarka  Instru- 
ments No.  200"  and  name  of  Ozarka  representative. 


Address City. 

County State . . . 


//VampoRftfER 


122  Austin  Avenue  A 
Chicago,  Illinois 


Gentlemen:  I  am  greatly  interested  in  the  FREE  bonk  "The 
Ozarka  PlanNo.lOO/'wherebylcansellyour  radio  instruments. 


Name. 


Address City. 

County State . . . 

*    Tested  and  Approved  by  RADIO  AGE    * 


Ask  the  Man  Who 
Wears  this  Button 


NOV  27  1925  ©ciB6S67i2 

RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


'1 


Ufa  Magazine  of  the  Hour 


Smith 

i  Manager 


A  Monthly  Publication 

Devoted  to  Practical 

Radio 


Frederick  A.  Smith 

Editor 


.^  

An  R.  F.  Receiver  You  Can  Rely  On — 

The  Radio  Age  MODEL  Receiver 


IN  presenting  to  its  readers  the  present 
Radio  Age  Model  Receiver  this  mag- 
azine believes  it  is  making  a  distinct 
contribution  to  the  sum  total  of  the  aver- 
age readers  experience  in  set  building,  in 
that  the  article  to  follow  is  written  co- 
incident with  the  construction  of  the  set; 
it  follows  the  newspaper  form  of  report- 
ing an  event  in  the  greatest  detail  con- 
sistent with  making  such  narrative 
personal  and  readable. 

The  Model  H  was  selected  after  re- 
ceiving quite  a  bit  of  data  from  fans  and 
others  who  seem  to  center  their  prefer- 
ence on  a  five  tube  set.  Straight  radio 
frequency  amplification,  with  a  variable 
means  of  controlling  regeneration  was 
adopted  in  order  to  prevent  as  much 
grief  as  possible  in  the  construction  and 
operation  of  the  set.  Despite  the  vast 
amount  of  knowledge  on  the  subject  of 
radio  we  feel  there  is  still  room  for  in- 
dependent thinking  on  the  part  of  serious 
minded  experimenters  and  manufacturers. 
Consequently  in  the  presentation  of  this 
article  we  would  like  to  have  the  com- 
ments, adverse  or  favorable,  of  our 
readers,  regardless  of  whether  they  are 
fans,  technicians  or  manufacturers.  The 
series  has  been  contemplated  to  reach 
well  into  the  next  year  and  in  that  period 
there  will  be  many  opportunities  for 
putting  into  practice  in  an  actual  re- 
ceiver some  of  the  best  suggestions 
brought  forth  by  a  discussion  of  this 
set. 

As  has  been  previously  announced  the 
Model  H  will  be  exhibited  by  the  Radio 
Age  in  its  booth  at  the  Chicago  Radio 
Show  and  after  the  exposition  it  will  be 
given  away,  details  of  circumstances 
governing  the  award  being  made  known 
to  every  visitor  at  the  Radio  Age  booth. 

The  idea  of  an  intimate  and  informal 
recital  of  the  various  steps  taken  in  the 
assembly  of  this  model  we  believe  will  be 
welcomed  alike  by  the  novice  or  the 
advanced  student  of  radio.  If  there  are 
short  cuts  in  such  construction,  or  if 
handy  kinks  occur  to  you  as  you  follow 
us  on  this  personally  conducted  tour,  do 
not  hesitate  to  let  us  have  the  advantage 
of  your  suggestions  or  criticisms.  We 
hope  to  make  Radio  Age  the  clearing 
house  or  forum  for  all  the  worth  while 


By  Radio  Age  Technical  Staff 


(Copyright:  1925) 


Latest  Refinements 
Added  to  Furnish 
Distance  and  Tone 


technical  and  practical  data  on  radio 
as  it  is  applied  to  ordinary  uses.  We 
can  neither  be  too  technical  nor  inanely 
simple  in  our  work;  rather  we  must 
adopt  a  middle  ground  in  which  good 
American  common  sense  plays  a  leading 
part. 

Here  We  Go 

Since  we  are  not  making  a  manufac- 
tured set  for  the  market  we  have  a  little 
more  latitude  in  the  construction  of  the 
Model  H.  The  progressive  system  of 
construction,  in  this  particular  instance, 
seems  best  adapted  to  properly  and 
clearly  conveying  the  ideas  to  the  mind 
of  the  reader.  In  all  this  work  there 
should  be  continuity  or  sequence,  at 
least  electrically.  Thus  we  can  build 
the  set  from  left  to  right  in  the  order  in 
which  the  various  units  and  parts  per- 
form their  respective  functions. 

The  Baseboard 

Perhaps  a  prettier  model  might  be 
made  if  sub-base  work  were  resorted  to, 
but  we  believe  there  is  still  ample  justifi- 
cation for  the  pine  baseboard,  with  the 
panel  firmly  affixed  to  the  front  edge  by  a 
number  of  long  screws.  Further  bracing, 
with  small  angle  braces,  can  be  used 
effectively  if  the  set  is  to  undergo  much 
handling.  The  baseboard  size  has  been 
determined  upon  as  seven-eighths  of  an 
inch  thick;  nine  and  a  half  inches  wide, 
and  twenty-five  inches  long.  The  length 
of  the  baseboard  is  a  half  an  inch  shorter 
at  each  end  than  the  bakelite  panel, 
which  is  a  7  by  26  by  3/16,  in  order  to 
allow  the  placing  of  the  completed  panel 
in  any  kind  of  a  cabinet  without  the 
baseboard  touching  cabinet  walls.  For 
home  use  we  would  not  treat  the  base- 


board but  since  it  is  to  be  exhibited, 
we  will  use  a  coat  of  asphaltum  paint, 
the  kind  used  on  storage  batteries,  there 
being  no  paraffin  handy. 

The  Panel 

We  now-  take  our  bakelite  panel,  get  a 
T  square  or  some  other  square  and  lay 
it  out.     First  run  a  line  from  end  to  end 
of  the  panel  3  1-2  inches  down  from  the 
top.      This    divides    the    panel    equally 
since  it  is  a  7  inch  panel  and  gives  us  a 
straight   line    all    the    way   across.      By 
previous  temporary   layout   of  the  ma- 
terial on  hand  we  decide  to  put  the  first 
variable  condenser   with   its  center  two 
and  a  half  inches  from  the  left  edge  of  the 
panel.     The  second  variable  is  5  inches 
from  the  first  one,  center  to  center,  and 
the  third  one  is  5  inches  from  the  second. 
Five    inches   from    the    third   condenser 
is  the  center  for  the  meter  hole.     Two 
inches  down  from  this  center  and  square 
with  the  center  hole  above,  is  the  hole  for 
the    rheostat    for    the    detector    stage. 
Back  up  again   to   the  center  line  and 
taking  4  inches  from  center  of  the  meter 
hole  we  put  another  punchmark  for  the 
combination     switch     and     pilot     light; 
then  three  inches  from  that  we  have  the 
hole  for  the  phone  jack.      This  almost 
completes  our  work  on  the  center  line. 
Using  the  templates  that  come  with  the 
condensers   we   set   and   punch    for   the 
three  condensers.      Not   having   a   tem- 
plate use  one  of  the  three  point  centering 
punches,  several  makes  of  which  can  be 
found  on  the  market.    The  lineup  on  the 
panel  along  the  center  line,  reading  from 
left  to  right,  is  as  follows:    first  variable, 
second  variable,  third  variable,  voltmeter 
(with  rheostat  below  it)  filament  switch 
and  finally  the  hole  for  the  jack. 

Now  draw  a  line  7/16  of  an  inch  from 
the  bottom  of  the  panel,  running  the 
line  all  the  way  across  the  panel.  This 
will  give  you  the  line  for  the  holding 
screws  for  the  panel.  Put  a  mark  at  13 
inches  (half  the  length  of  the  bakelite). 
Then  halve  the  distance  between  the 
center  and  the  left  edge;  then  halve  the 
distance  between  the  center  and  right 
edge.  This  will  give  you  three  holes  for 
mounting  the  panel  against  the  base- 
board.    Put  another  hole  an  inch  and  a 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


half  from  the  right  end  of  the  panel,  and 
one  the  same  distance  from  the  left 
edge.  This  will  give  five  holes  in  all  and 
will  be  enough  to  hold  any  panel  under 
most  any  circumstances. 

Ten  inches  from  the  left  edge  of  the 
panel  and  one  and  a  quarter  inches  down 
make  another  punchmark  for  the  twin- 
resistor.  This  concludes  the  punch- 
marks  on  the  panel.  Make  them  very 
lightly  at  first  if  you  are  not  sure  of 
yourself.  Re-check  your  measurements 
and  if  o.  k.,  then  go  ahead  with  a  heav- 
ier punch-mark  so  the  drill  will  not  slip 
out   and   cut    wrong    position. 

Cutting  Big  Holes 

For  cutting  the  meter 
hole,  take  a  pair  of 
compasses  and  scribe 
a  circle  two  and  one- 
sixteenth  of  an  inch 
in  diameter.  If  you 
have  a  fly-cutter  the  job 
will  be  easy.  If  not 
make  a  number  of  punch 
marks  around  the  scrib- 
ed circle  and  drill  small 
holes  around  the  circle, 
later  cutting  from  hole 
to  hole  with  a  sharp 
instrument  until  the  cir- 
cle is  complete.  Clean 
with  a  rat-tail  file.  For- 
tunately for  us  we  resur- 
rected, from  the  dust  of 
a  generation,  the  old 
foot  power  scroll  saw 
and  managed  to  make  a 
very  nice  job  out  of 
what  might  otherwise 
have  been  a  tedious  pro- 
cess. 


baseboard  and  putting  in  the  lower 
wiring  before  parts  are  placed  on  the 
panel. 

Socket  Line 

Mark  off  a  line  three  inches  from  the 
panel  on  the  baseboard  for  the  socket 
line.  Four  inches  from  the  left  end  of 
the  baseboard  make  a  punch  mark  for 
the  screw  on  the  left  side  of  the  Benjamin 
sockets  which  are  being  used.  Five  inches 
to  the  right  of  this  mark  will  be  the  left 
hole  for  the  second  socket.  Six  and  a  half 
inches  is  the  distance  from  the  second 
to  the  third  socket  screw  hole.     From  the 


Oh!  for  Single  Mount- 
ings 


LIST  OF  PARTS 


3 
3 
2 
1 
3 
5 
4 
1 
1 
1 
8 
3 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
3 
2 
1 
2 
1 
1 
1 
100 
100 
20 


Anyone  who  has  as- 
sembled more  than  one 
radio  set  will  join  with 
us  in  wishing  for  the 
universality  of  the  single 
hole  mounting  applied 
to  everything  that  is  at- 
tachable to  a  panel.  Ev- 
erything on  the  panel  is 
single  mounting  except 
the  three  condensers; 
four  holes  apiece  must  be  drilled  for 
them.  The  centers  and  three  holding 
screw  holes  for  the  condensers  should  be 
made  in  accordance  with  the  directions 
accompanying  the  condensers.  We  al- 
ways ream  the  center  hole  out  large 
enough  to  obviate  the  possibility  of 
binding  on  the  shaft.  The  holes  for  the 
holding  screws  should  be  countersunk 
in  order  to  allow  the  screw  heads  to  go 
up  snug  and  smooth  with  the  surface  of 
the  panel. 

From  the  time  We  started  out  with  the 
baseboard  until  the  present  moment 
when  we  have  finished  drilling  the  panel 
two  hours  have  elapsed.  See  how  much 
time  you  can  cut  off  that.  If  you  have 
successfully  withstood  the  fumes  of  the 
carbolic  acid,  iodine,  permanganate  of 
potash  and  other  hospital  odors  that 
greet  you  when  drilling  panels,  you  are 
now  ready  to  take  the  next  step,  which  is 
the   assembling   of   the   material   on   the 


Silver-Marshall  .0005  S.  L.  F.  Variable  condensers 

Henninger  type  "D"  r.f.  transformers. 

Erla  Concert  Grand  audio  transformers. 

Bremer-Tully  twin  resistor,  variable. 

X  L  variodensers,  2  type  N,  1  type  G. 

Benjamin  Cleratone  sockets  for  201-A  tubes. 

Amperites  for  201-A  tubes. 

Bradleystat. 

Jewell  0-8  d.c.  voltmeter. 

Yaxley  combination  switch  and  pilot  light. 

X  L  metal  spring  binding  posts. 

Bremer-Tully  vernier  dials. 

Daven  1  meg  grid  leak. 

Muter  1  mfd  bypass  condenser. 

Muter  .001  mfd  bypass  condenser. 

Apex  choke  coil. 

Pacent  single  circuit  jack. 

Pacent  phone  plug. 

Bakelite  panel  7  x  26  x  3-16. 

Kodel  microphone  type  loud  speaker. 

American  Electric  loud  speaker  unit. 

Seaman-Jones  enclosed  loud  speaker. 

General  Electric  2  ampere  Tungar. 

DeForest  tubes,  2  r.f.  and  1  detector. 

Daven  tubes,  1  MU20,  1  MU6. 

4.5  volt  Ever-Ready  C  battery. 

Ever-Ready  45  volt  block  B  batteries. 

Six  volt  World  A  battery. 

Cabinet,  Newark  Electric  Co. 

Jefferson  tube  rejuvenator. 

Kellogg  conection  lugs. 

Feet  Belden  enamel  antenna  wire. 

Lengths  square  Dudlo  bus  bar  wire. 


socket  which  is  the  cushion  type,  allowing 
the  tube  to  float  on  spring  contacts. 
This  gives  you  an  opportunity  of  making 
a  solid  wire  assembly  direct  to  the  sockets 
instead  of  using  flexible  wire  assembly, 
contributing  somewhat  to  the  finished 
appearance  of  the  set.  Place  the  sockets 
so  the  filament  connections  are  towards 
the  panel,  this  putting  the  grid  on  the 
left  and  the  plate  on  the  right,  away  from 
the  panel.  If  you  happen  to  strike 
an  unusually  tough  baseboard  and  have 
difficulty  in  running  up  the  screws,  take  a 
bar  of  laundry  soap  and  soap  up  the 
screws;  you'd  be  surprised  how  easy 
they  go  in  after  such 
treatment.  After  you 
have  screwed  down  the 
sockets  take  a  square 
edge  and  lay  along  the 
line  to  see  that  all  sock- 
ets are  straight;  this 
will  help  later  in  running 
your  wire.  Slight  dis- 
crepancies in  alignment 
can  be  equaled  through 
unscrewing  the  sockets; 
the  play  in  the  screw 
holes  will  generally  be 
sufficient  to  throw  them 
all  in  lineunlessyou  have 
been  too  careless  i  u  mark- 
ing off  the   socket   line. 


(While  the  above  parts  were  used  in  the  December  Model  H,  any 
parts  of  equal  merit  may  be  consistently  used  in  the  construction  of 
such  a  receiver.) 


Low  Potential  Lines 


third  to  the  fourth  the  distance  is  3% 
inches,  while  from  the  fourth  to  the  fifth 
socket  screw  hole  is  four  inches.  This 
lines  up  your  sockets  so  they  center  be- 
tween the  three  variables^  and  are  fairly 
well  spaced  at  the  audio  end  of  the  base- 
board. Before  screwing  down  the  Ben- 
jamin sockets  be  sure  all  the  hexagonal 
nuts  on  the  four  binding  posts  are  up 
tight.  Do  not  exert  too  much  force  in 
tightening  the  hex  nutsor  you  might  either 
strip  the  thread  or  throw  the  spring  out  of 
alignment.  For  hurriedly  running  up  the 
binding  posts  on  these  sockets  a  set  of 
Stevens  "spin-tite"  Wrenches  will  prove 
quite  handy.  Since  you  have  a  socket 
line  marked  off  the  left  hand  screws 
(round  head  wood  screws)  can  be  put  in  to 
hold  the  sockets  in  place.  True  them  up 
against  the  line  by  sighting  through  the 
right  socket  hole,  then  put  the  screw  in 
the  upper  right  corner.  Only  two  screws 
are  necessary  to  hold  down  this  kind  of 


To  facilitate  laying  of 
the  negative  and  posi- 
tive A  wires,  grid  returns 
and  other  points  of  low 
potential,  it  is  suggested 
you  do  not  have  any- 
thing mounted  on  the 
panel.  Let  the  panel  be 
attached  to  the  base- 
board (if  necessary  you 
candrillitinthisposition, 
probably  better  than 
laying  on  the  bench). 
Then  go  ahead  with 
your  negative  A  line. 
Refer  to  Fig.  1,  which  is 
the  schematic  of  Radio 
Age  Model  H.  All  wir- 
ing should  be  done  from 
the  schematic,  never  the 
isometric  plan  or  any 
other  view  of  a  set,  since  it 
is  generally  assumed  the  schematic  is  al- 
ways correct  electrically,  whereas  errors 
can    creep    into  perspective  drawings. 

For  hooking  up  the  sockets  and  other 
units  we  will  make  use  of  a  time  saving 
device  known  as  a  soldering  lug.  The 
kind  which  we  used,  made  by  the  Kellogg 
people,  has  a  generous  soldering  surface 
and  saves  considerable  time  that  would 
otherwise  be  spent  in  making  loops  and 
curleycues.  In  addition  we  can  make  a 
much  more  symmetrical  job.  The  left 
hand  lower  binding  post  on  all  the  sockets 
is  negative  A.  This  line  can  be  run 
straight  from  the  first  socket  on  the  left 
over  to  the  extreme  right  and  then  around 
to  the  binding  post  panel  at  the  right 
rear  of  the   baseboard. 

Binding  Post  Strip 

At  this  point  it  would  be  a  good  idea  to 
put  on  the  binding  post  strip  attached 
(Turn  to  page  10) 


10 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


to  the  rear  of  the  baseboard.  In  this  set 
8  binding  posts  are  used  made  by  the 
XL  Radio  Laboratories,  Vno  also  make 
the  XL  variodenser  which  we  are  using 
in  this  model.  Reading  from  right  to 
left  the  binding  posts  which  are  located 
about  7/8  of  an  inch  apart  are  as  follows: 
plus  A,  minus  A,  minus  B,  plus  C, 
minus  C,  plus  22  B,  plus  45  B  and  plus 
90  B.  Each  one  of  the  binding  posts 
is  fitted  with  a  soldering  lug  so  connec- 
tion can  be  easily  made  from  the  rear 
of  the  strip,  which  is  about  8  inches  long 
and  one  and  a  quarter  inches  wide.  It 
can  be  made  of  bakelite  or  hard  rubber 
and  should  be  affixed  to  the  edge  of  the 
base.  These  details  may  be  seen  from 
Fig.  2  which  is  an  isometric  sketch 
showing  all  parts  in  their  proper  relation. 
Also  see  Fig.  3  which  is  a  photograph 
of  the  set  looking  down  upon  it  and 
showing  all  units  in  place  but  not  wired. 
Figure  4  is  the  same  photograph  with 
the  exception  that  all  wiring  is  shown 
as  in  the  completed  job.  Figure  5  gives 
a  front  view  of  the  Radio  Age  Model 
H.  It  might  not  be  a  bad  idea  to  scan 
all  the  diagrams  and  photos  carefully 
before  going  ahead  so  as  to  get  a  strong 
mental  image  of  the  layout  as  you  go. 

With  the  sockets  in  position,  the  bind- 
ing post  strip  secured  to  the  extreme 
right  edge  of  the  baseboard  in  the  rear, 
the  r.  f.  coupler  and  transformers  in  place 
and  the  audio  transformers  located,  we 
are  ready  to  go  ahead  with  the  soldering. 

Soldering  the  Set 

Many  of  our  readers  have  asked  us 
regarding  the  best  manner  of  soldering. 
Our  preference  is  for  rosin  core  solder 
with  a  cleaning  solution  made  up  of  a 
saturated  solution  of  rosin  in  alcohol. 
This  acts  as  an  excellent  flux  and  you 
need  not  worry  about  corrosion.  Do 
not  use  acid  core  solder  or  any  acid 
flux.  Acid  flux  has  cost  many  a  manu- 
facturer a  good  sum  in  returned  sets 
(this  applies  principally  to  the  early 
days   of   the   broadcast   craze).      If   you 


have  an  electric  iron  some  time  may  be 
saved  in  the  soldering,  otherwise  you  will 
probably  have  to  chase  back  and  forth 
between  the  set  and  the  kitchen  range, 
unless  you  have  a  Bunsen  burner  in  the 
work  shop.  A  five  cent  lump  of  sal- 
ammoniac  on  the  bench  onto  which  you 
occasionally  rub  the  iron  will  serve  to 
keep  it  from  burning  off  and  keep  it  well 
tinned. 

We  have  a  personal  preference  for 
straight  lengths  of  square  busbar  wire 
although  the  round  may  be  used;  in 
fact  any  kind  of  wire  may  be  used  but  for 
speeding  and  prettying  up  the  job 
either  the  square  or  round  busbar  is 
best.  Wire  used  in  the  Model  was 
furnished  for  this  occasion  by  the  Dudlo 
Manufacturing  Co. 

Having  put  a  soldering  lug  on  each 
of  the  left  hand  filament  posts  and  made 
it  tight,  take  a  pair  of  long  nose  pliers 
and  turn  the  hole  end  of  the  lug  so  the 
hole  points  along  the  line  of  the  sockets. 
This  means  to  turn  the  hole  on  the  lug 
at  right  angles  to  the  position  it  normally 
occupies.  In  this  position  you  can  feed 
busbar  wire  straight  through  from  the 
first  to  the  fifth  socket  all  in  one  piece. 
Put  a  tiny  drop  of  alcohol-rosin  flux  on 
the  wire  and  the  lug  and  solder  with  a 
good  hot  iron.  Solder  each  one  of  the 
lugs.  At  the  extreme  right  of  the  set 
allow  the  wire  to  project  a  little  beyond 
the  socket  line  as  you  will  make  a  turn 
here  to  lead  the  wire  to  the  negative  A 
binding  post  on  the  strip  in  the  rear. 
The  wire  and  the  lugs  are  now  elevated 
a  little  above  the  floor  of  the  baseboard. 
Push  each  lug  down  carefully,  one  lug 
with  each  thumb,  so  the  wire  lays  flat 
along  the  board.  This  is  now  your  low 
potential  line  and  may  be  left  uninsu- 
lated if  desired.  All  grid  returns,  etc., 
are  made  fast  to  this  line  as  you  will 
observe  in  the  schematic  diagram,  Fig.  1. 

Ground   Wire. 

The  low  potential  line  is  also  your 
ground   line   so   the   ground   tap   on   the 


first  Henninger  D  coil  may  be  run 
straight  toward  the  panel  to  meet  the 
negative  wire.  It  is  this  wire  to  which  all 
rotors    of    the    condensers  are  attached. 

As  stated  before  a  single  piece  of  wire 
may  be  used  as  the  base  line  onto  which 
may  be  soldered  all  the  negative  filament 
connections,  grid  returns  from  the  three 
variable  condensers,  the  rotors  of  the 
three  condensers,  the  plus  of  the  C 
battery  (unless  you  wish  to  include  this 
battery  on  the  wiring  shown  on  the  bind- 
ing post  strip)  the  ground  connection, 
and  grounded  side  of  the  1  mid  bypass 
condenser  whose  other  connection  is  to 
the  common  tap  at  the  bottom  of  the 
two  primaries  of  the  r.f.  transformers. 

For  simplicity's  sake  consider  the  left 
hand  filament  terminal  on  the  socket  the 
negative  and  follow  Fig.  1,  the  schematic, 
in  wiring  up  everything.  After  getting  in 
all  the  wiring  that  is  common  with  the 
negative  terminal,  you  can  run  a  wire 
over  to  the  negative  A  binding  post  on 
the  strip,  this  being  common  with  the 
negative  B  and  positive  C  battery  leads. 

Positive  Line 

Next  comes  the  positive  A  line  which 
takes  in  the  Amerpites  in  the  positive  line 
to  the  first,  second,  fourth  and  fifth 
tubes.  In  the  third  tube  you  will  note  a 
Bradleystat  to  provide  variable  filament 
voltage  for  the  soft  detector,  if  one  is 
used.  The  Jewell  0-8  d.c.  voltmeter,  is 
connected  from  the  negative  of  the  A 
to  the  right  hand  filament  terminal  on 
the  third  socket  so  as  to  give  you  actual 
voltage  applied  to  the  detector.  The 
Amperites  will  take  care  of  proper  voltage 
to  the  balance  of  the  tubes.  The  combina- 
tion switch  and  pilot  light,  made  by  Yax- 
ley, should  be  connected  between  the 
positive  A  and  the  last  Amperite  as 
shown  in  Fig.  1.  The  light  acts  as  a 
warning  the  set  is  still  on;  probably 
intended  for  some  of  our  radio  fans  who 
have  a  tendency  to  nap  while  listening 
and  who  might  forget  the  set  was  on  if  a 
(Turn  to  page  12) 


Fig. 


3.      Photograph  of  Radio  Age  Model  taken  from  above,  showing  all  parts  in  position  but  not  wired.     This  picture  and  the  iso- 
metric, Fig.  Z,  should  help  the  fan  to  get  a  clear  idea  of  the  unwired  set. 


12 


RADIO  AGE /or  December,  1925 


The  Magazine  of  the  Hour 

p,     r„;     r~j     r— |     —i     ~,     — ^    .--, 


Fig.  4. 


This  picture,  looking  down  on  baseboard,  shows  all  units  locatea  ana  wired. 

Fig.  1  for  accuracy  in  wiring. 


This  is  the  complete  job.      Follow  schematic 


station  quit  transmission.  This  will 
conclude  the  low  potential  wiring.  By 
use  of  the  Kellogg  soldering  lugs,  sockets 
lined  up  properly  and  Dudlo  square  wire 
we  are  enabled  to  run  practically  all  of 
the  low  potential  stuff  without  resorting 
to  the  favorite  Italian  insulating  dish. 
If  you  are  in  doubt,  however,  use 
spaghetti. 

R.  F.  Coils 

The  Henninger  type  D  coils  are 
located  with  their  centers  about  on  a  line 
with  the  condenser  centers  and  as  far 
back  from  the  condensers  as  the  base- 
board will  permit.  Not  much  use  of 
slamming  your  r.f.  units  (regardless  of 
by  whom  made)  up  against  the  field  of  a 
variable  condenser  and  running  up  the 
r.f.  resistance  of  the  unit.  These  coils 
are  marked  P  and  B  for  the  primary, 
meaning  plate  and  B  battery  (except  in 
the  case  of  the  first  unit  which  is  the 
antenna  coupler;  there  the  P  and  B  can 
mean  antenna  and  ground.  The  secon- 
daries are  all  marked  G  and  F,  the  former 
grid  and  the  latter  filament.  No  chance 
to  go  wrong  there.  Remember  the  rotors 
of  the  variables  ALWAYS  go  to  filament 
and  the  stators  to  grid;  forget  it  and  you 
issue  an  engraved  invitation  to  body 
capacity  to  attend  the  ceremonies. 

The  XL  variodenser  which  is  being 
used  as  a  grid  condenser  is  mounted  right 
up  to  the  grid  terminal  of  the  detector 
tube;  see  Fig.  2  on  page  10.  This  unit 
has  clips  for  the  Daven  1  meg  grid  leak 
being  used. 

The  use  of  the  Apex  choke  coil  is  more 
or  less  experimental  with  the  user  and  the 
type  of  material  in  the  set.  In  the  original 
rough  layout  it  was  used  while  in  the 
finished  product  it  was  found  better 
results  were  secured  without  it.  Better 
arrange  to  leave  it  in  and  then  short  out 
by  means  of  clips;  try  for  yourself  and 
see  which  you  prefer.  Such  a  choke  is  a 
handy  thing  to  have  around  the  house 
for  future  hookups. 


Audio  Stages 
The  Erla  Concert  Grand  audio  trans- 
formers have  P  and  G  terminals  arranged 
so  the  transformers  may  be  mounted  close 
to  the  sockets  in  the  interest  of  space 
economy.  The  plate  and  grid  terminals 
are  on  the  front  towards  the  line  of 
sockets  and  the  B  and  F  are  at  the  back 
away  from  the  sockets;  this  permits 
short  wiring  on  both  sides  since  the 
transformers  are  close  to  the  sockets  and 
also  to  the  binding  post  strip  at  the 
right  rear  of  the  baseboard.  The  primary 
of  the  first  audio  is  shunted  by  a  .001 
fixed  condenser,  Muter.  The  value  of 
this  does  not  seem  to  be  critical,  ap- 
parently anything  above.  001  will  suffice, 
although  too  great  a  capacity  will 
probably  reduce  the  signals  inordinately. 
The  two  F.  terminals  on  the  transformers 
are  commoned  and  led  to  the  minus  C 
terminal  on  the  binding  post  strip. 

Oscillation  Control 

As  a  means  of  control  of  any  tendency 
on  the  part  of  the  tubes  to  oscillate  we 
adopted  the  expedient  used  by  the 
Bremer-Tully  people  in  their  "Counter- 
phase"  set,  which  method  is  made  the 
subject  of  recent  patents  by  Harry  A. 
Bremer,  of  the  above  mentioned  lirm. 
Essentially  it  consists  of  a  twin  variable 
resistance;  one  leg  of  which  is  in  series 
with  the  positive  B  potential  applied  to 
the  r.f.  tubes  and  the  other  in  series  with 
a  neutralizing  capacity  from  plate  in- 
ductance of  one  tube  to  the  grid  of  the 
same  tube.  The  resistor  acts  in  a  dual 
capacity;  it  limits  the  plate  potential  on 
the  tubes  by  the  voltage  loss  method  and 
at  the  same  time  changes  the  capacity  of 
the  neutralizing  capacity  through  in- 
troducing resistance  in  series  with  it. 
While  the  maximum  efficiency  of  such  a 
system  of  balance  is  not  fully  realized 
unless  the  inductances  and  associated 
balancing  windings  are  built  one  for  the 
other,  nevertheless  the  system,  we 
believe,  has  more  in  its  favor  than  the 


simple  capacity  method  of  neutralization 
where  the  balance  is  set  once  for  all  for  a 
given  set  of  tubes  and  which  process  does 
not  take  into  account  the  necessity  for  a 
change  more  or  less  in  step  with  the 
wavelength  changes.  We  all  know  the 
limitations  of  the  neutrodons  which  give 
us  good  efficiency  on  one  band,  fair  on 
another  and  punk  results  on  still  another. 
Mr.  Hazeltine  should  have  gone  further 
with  his  system  so  the  Dial  Twisters 
could  squeeze  every  bit  of  energy  out  of 
all  waves.  The  aforementioned  twin 
resistor  is  mounted  on  the  panel  where  it 
becomes  a  semi-control;  generally  speak- 
ing in  the  model  it  came  into  play 
principally  when  on  the  extremely  short 
waves  to  prevent  oscillation,  while  on 
the  higher  bands  little  change  was  re- 
quired. 

Size  of  Condensers 

The  Silver- Marshall  s.l.f.  variables, 
three  in  number,  were  changed  from  the 
original  .00035  mfd  in  the  hastily  put- 
together  affair  to  the  .0005  mfd  type  in 
the  final  receiver  in  order  to  take  ad- 
vantage of  KYW  and  KSD  which  were 
not  in  reach  with  the  .00035.  This  is 
probably  on  account  of  the  inductances 
which  might  have  been  designed  for  the 
.0005  size  instead  of  a  smaller  capacity. 
If  you  care  to  sacrifice  the  two  high  wave 
stations  (we  wouldn't  suggest  it  for  a 
moment)  you  can  use  the  .00035;  other- 
wise the  .0005  is  proper.  The  s.l.f.  type 
was  chosen,  together  with  the  three 
Bremer-Tully  vernier  dials,  in  order  to 
afford  a  little  greater  facility  in  tuning 
the  secondaries  than  with  the  straight  line 
capacity.  The  selectivity  of  one  con- 
denser as  compared  with  another  (s.l.f. 
versus  s.l.c.)  is  identical  provided  the 
inductances  are  good  ones.  Neither  s.l.f. 
nor  s.l.c.  will  make  a  selective  set  if  the 
inductances  are  broad;  the  only  thing  we 
get  from  the  s.l.f.  on  account  of  its  cut-a- 
way construction  is  a  more  equal  spacing 
of  frequencies  with  less  nervous  prostra- 


RADIO  AGE /or  December,  1925 


The  Magazine  of  the  Hour 


13 


tion  in  sliding  over  a  station  due  to  a 
minute  change  in  capacity  of  the  con- 
denser. The  frequencies  covered  and 
the  graduations  on  the  dial  do  not  agree, 
nor  could  they  be  expected  to.  For  such 
to  be  the  case  both  the  inductances  and 
the  capacities  would  have  to  be  finely 
balanced,  and  such  a  process  is  out  of  the 
question  in  ordinary  radio.  Accordingly 
graduation  of  the  dial  scale  is  an  arbitrary 
method  of  dividing  a  full  circle;  most 
manufacturers  use  the  half  circle  divided 
into  100  degrees  while  some  adopt  the 
360  degree  rotation  with  its  attendant 
larger  scale. 

Few  More  Details 

A  few  more  notes  and  the  staff  will 
have  made  a  round-up  of  all  the  details 
necessary  in  the  actual  construction  of  the 
receiver. 

In  the  twin  resistor  the  terminal  B  is 
put  in  series  with  the  plate  potential;  the 
terminal  R  goes  through  the  single  or 
double  neutralizing  capacities,  as  you 
desire,  while  the  terminal  P  is  common 
with  both  the  B  terminals  on  the  prim- 
aries of  the  second  and  third  r.f.  trans- 
formers. The  use  of  the  first  balancing 
capacity  is  shown  in  dotted  lines  in  the 
schematic  diagram,  Fig.  1.  In  the  actual 
set  the  two  XL  type  N  vardiodensers  are 
used  because  we  found  better  results  as 
contrasted  with  the  use  of  a  single 
capacity.  The  resistance  R  is  then  in 
series  with  the  two  capacities  and  has  a 
tendency  to  allow  dual  control  of  balanc- 
ing capacity. 

In  mounting  the  audio  transformers 
just  to  be  consistent  we  grounded  the 
cases  to  the  negative  A  line.  The  two 
transformers  were  placed  close  enough  so 
only  a  little  loop  of  busbar  wire  was 
necessary  to  bond  the  two  together 
between  transformers  while  about  an 
inch  and  a  half  piece  of  bus  wire  served 
to  run  from  the  right  side  of  the  last  audio 
to  the  negative  A  line  passing  nearby. 

Tell  Us  About  It 

Perhaps  during  the  reading  of  this 
account  our  readers  have  thought  of 
short  cuts  in  assembly,  or  other  means  of 


making  the  description  simple  and  lucid 
to  the  average  reader.  Radio  Age  is 
always  (and  has  ever  been)  glad  to  hear 
from  any  of  its  readers  regardless  of 
whether  the  suggestion  is  favorable  to 
the  magazine  or  not.  If  we  merely 
saved  all  of  the  honeyed  missives  ours 
would  be  indeed  a  cloyed  existence.  So  if 
something  occurs  to  you  about  this  set  or 
its  manner  of  presentation,  hasten  to  the 
mill  or  grab  the  well  known  pencil  and 
dash  off  your  comments  while  you  are  in 
the  mood. 

After  all  of  the  wiring  had  been  done 
the  whole  thing  was  checked  and  re- 
checked.  No  one  but  a  department 
handling  thousands  of  letters  can  ap- 
preciate the  value  of  checking  ever  your 
work  once  it  is  finished,  especially  if  the 
work  is  done  at  odd  moments.  In  many 
cases  of  trouble  it  can  definitely  be  placed 
at  the  door  of  failure  to  check  the  wiring. 
Even  after  you  have  checked  back  your 
wiring  against  the  schematic  shown  on 
Fig.  1  insert  your  tubes  in  the  socket,  one 
at  a  time,  so  if  there  is  a  conflagration  it 
will  not  burn  up  all  of  the  five  tubes. 

In  putting  the  receiver  into  operation 
makes  the  necessary  connections  on  the 
binding  post  strip,  which  reads  from  right 
to  left:  plus  A,  minus  A,  minus  B,  plus 
C,  minus  43^  C,  plus  22  (or  45  if  using 
other  than  soft  detector)  plus  45  (higher 
if  you  care)  and  finally  the  plus  90  or 
120  volts. 

Dial  Readings 

The  first  and  second  variable  con- 
densers will  probably  read  within  a  degree 


of  each  other,  while  the  third  condenser, 
possibly  on  account  of  its  grid  condenser 
and  leak,  will  read  about  from  ten  to 
fifteen  degrees  higher.  Thus  if  you  pick 
up  a  station  at  zero  on  the  first  and  second 
condensers,  the  third  one  controlling  the 
secondary  of  the  detector  circuit,  will 
probably  read  15  degrees.  In  working  on 
locals  it  is  a  simple  matter  to  get  your 
bearings,  .but  those  living  away  from  a 
broadcasting  station  will  perhaps  have  to 
exert  more  patience  in  getting  the  first 
signal.  Turn  the  knob  of  the  twin 
resistor  to  the  extreme  right  in  working 
on  the  short  waves.  The  capacities  of 
the  two  balancing  conden'sers  should  be 
as  near  minimum  as  possible,  although 
personal  experimentation  on  this  score 
may  help  some.  Minimum  capacity  with 
these  variodensers  means  running  the  set 
screw  out  as  far  as  it  will  go  so  the  plates 
of  the  condenser  will  be  farthest  apart. 

More  In  January 

In  the  December  model  we  have  made 
use  of  the  three  condensers  and  dials 
because  there  are  quite  a  number  of  fans 
who  have  the  three  dial  sets  and  who 
perhaps  might  desire  to  make  a  change 
so  as  to  give  greater  flexibility  than  they 
now  possess.  Frankly  and  editorially  we 
are  not  sold  on  the  three  dial  control  and 
will  have  something  further  to  say  on 
this  subject  in  the  January  number  which 
will  describe  the  further  work  of  the  staff 
in  presenting  advances  along  these  lines. 
However  for  those  who  already  have  the 
three  dials  the  foregoing  will  allow  a 
chance  to  secure  greater  flexibility  as 
regards  the  control  of  undesirable  oscilla- 
tions due  to  only  partial  balance  of  tube 
capacities  at  all  waves.  It  will  also  allow 
the  experimenter  to  begin  work  on  the 
restricted  field  inductance.  No  form  of 
winding  so  far  is  completely  fieldless, 
nevertheless  the  more  recent  trend  of 
inductance  design  is  certainly  cutting 
down  the  area  of  the  field  and  permitting 
the  assembly  of  r.f.  units  without  the 
heretofore  critical  angle,  upon  which 
subject  there  is  scarcely  a  unanimity  of 
opinion.  At  least  we  honestly  believe 
there  is  a  worthwile  advantage  in  the  use 


Fig.  5.     Here  is  your  finished  set  shown  in  its  cabinet  with  the  Kodel  Microphone  loudspeaker  placed  on  top. 


14 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


of  the  restricted  windings  as  compared  to 
the  straight  solenoid.  For  further  data 
on  the  restricted  field  inductance  we 
would  refer  you  to  the  January  number 
in  which  the  matter  will  be  gone  into  in 
detail  as  the  construction  of  the  Model 
_HX  is  outlined  for  the  benefit  of  our 
readers. 

Ere  we  forget,  be  sure  to  use  the  little 
templates  furnished  with  the  vernier  dials 
in  order  to  get  the  holding  hole  for  the 
dial  in  proper  position.  The  instructions 
accompaning  the  dial  will  show  clearly 
the  method.  There  is  no  one  thing  on  a 
radio  set  that  will  cause  more  cussing  in 
actual  operation  than  a  dial  binding  on 
the  panel,  or  a  condenser  shaft  for  which 
due  space  allowance  has  not  been  made 
and  which  consequently  binds  against  the 
panel. 

Tuning  the  Set 

After  once  getting  your  first  station  on 
the  lower  band,  close  to  zero  on  the  first 
two  condensers  and  about  fifteen  on  the 
right  hand  one,  you  should  encounter  no 
difficulty  in  jumping  from  one  to  the 
other  right  up  the  wavelength  scale. 
In  increasing  capacity  (locally)  you  can 
do  it  in  bounds  of  five  degrees  at  a  time. 
However  for  those  at  a  distance  from  a 
transmitter  it  would  be  better  to  make 
the  jumps  in  two  degree  steps. 

In  the  diagram  the  ground  and  the 
filament  connections  are  shown  as  com- 
mon. Under  certain  circumstances  this 
will  give  a  strong  signal,  and  it  might  be 
too  strong  for  use  under  congested  radio 
conditions.  Separating  the  primary  in- 
ductance connection  so  the  ground  tap 
goes  to  ground  and  cutting  apart  the  tie 
between  the  ground  and  the  negative 
filament  will  serve  to  sharpen  up  the  set 
to  some  extent  although  at  a  sacrifice  of 
volume.  In  cases  of  strong  local  signals 
a  certain  amount  of  the  excess  energy  in 
the  antenna  circuit  finds  its  way  to  the 
grid  of  the  first  and  succeeding  tubes  via 
the  common  filament  connection.  Theo- 
retically the  only  cure  for  this  condition 
would  be  individual  A  and  B  batteries 
and  all  units  shielded  so  as  to  take  full 
rdvantage  of  the  repeater  action  of  each 
tube,  but  such  a  thing  is  not  possible  in 
the  average  American  radio  household 
so  we  will  dismiss  that  thought  from  our 
minds. 

Serves  A  Purpose 

We  feel  the  Model  H  receiver  will  be  a 
good  one  for  the  use  of  our  friends  who 
are  afflicted  with  critical  angle  inductances 
and  tubes  that  make  violent  protest 
against  being  operated  on  the  lower  wave 
band  without  adequate  means  of  balanc- 
ing tube  capacities.  We  do  not  wish  you 
to  gain  the  impression  that  this  will  be 
the  ultimate  in  receivers  for  there  is 
always  room  for  honest  experimentation 
in  the  assembly  of  associated  apparatus 
to  get  maximum  efficiency.  In  the  next 
of  this  series  to  appear  in  the  Radio  Age 
for  January  another  type  of  receiver  will 
be  described  which  We  believe  will  be  an 
improvement  over  the  present  model. 
From  time  to  time  as  we  work  on  these 
sets  changes  and  refinements  occur  to  us 
which  offer  an  opportunity  of  incorpora- 
tion in  succeeding  models  and  we  would 
be  derelict  in  our  duty  to  our  readers  if 


we  did  not  give  them  the  benefit  of  these 
advances,  each  one  slight  by  itself 
perhaps,  but  in  the  aggregate  constituting 
an  advancement  in  set  building. 

Maybe  some  of  our  readers  have  gone 
over  the  same  ground  covered  in  the 
present  article.  Perhaps  they  met  with 
success  or  the  reverse.  We  would  like  to 
have  the  benefit  of  their  advice.  If  you 
see  something  in  the  Model  H  which  you 
believe  may  be  improved  to  give  greater 
efficiency,  do  not  hesitate  to  inform  us  of 
that  fact  and  let  us  broadcast  it  to  the 
fraternity  at  large.  The  greatest  factor, 
in  the  building  up  of  the  vast  radio 
industry,  aside  from  the  purely  financial 
and  patent  angles,  has  been  the  almost 
amazing  number  of  devotees  of  the  art. 


MORE  DATA 

Incomplete  details  on  building 
the  super-het  without  intermediate 
stages,  prepared  by  Roscoe  Bundy 
in  the  November  number,  prompts 
Radio  Age  to  give  further  details 
from  the  author  which  might  help 
many  of  the  constructors. 

The  diameter  of  tubing  for  the 
oscillator  and  the  antenna  tuning 
inductance  is  3J^  inches.  Separa- 
tion between  windings  may  be  from 
a  quarter  to  a  half  inch,  depending 
upon  the  degree  of  coupling  desired. 
The  secondary  of  46  turns  has  a  tap 
at  the  10th  turn  from  the  filament 
end. 

In  making  the  RFT  1  which  is  a 
special  coupler,  either  of  several 
methods  may  be  followed.  It  may 
be  wound  on  a  3J^  inch  tube,  but 
will  be  bulky.  A  honeycomb  coil 
of  approximately  the  same  number 
of  turns  may  be  used  and  tap  taken 
off  at  the  90th  turn;  or  the  RFT 
may  be  wound  on  spools  with  the 
winding  scattered.  The  number  of 
turns  and  the  size  of  wire  is  as 
given  in  the  November  number  but 
the  form  of  the  inductances  was 
omitted.  A  little  experimentation 
on  the  part  of  the  reader  will  pro- 
bably solve  the  difficulty. 


Show  us  a  single  calling  or  science  which 
can  number  its  adherents  to  anything 
near  the  hosts  of  radio  enthusiasts.  These 
enthusiasts  are  not  merely  listeners; 
great  numbers  of  them  are  actual  tinker- 
ers,  and  it  is  the  tinkerer  with  a  genuine 
intellectual  curiosity  to  see  what  makes 
the  darn  thing  tick  who  can  be  considered 
the  one  responsible  for  many  of  the 
changes  in  the  game.  This  is  not  in 
disparagement  of  the  vast  sums  spent  on 
scientific  research  by  trained  technicians 
employed  by  the  industry  for  undoubted- 
ly they  too,  are  responsible  in  a  great 
measure  for  the  wonderful  strides  taken 
during  the  few  years  which  have  in- 
tervened since  the  close  of  the  World 
War  But  mass  experimentation  re- 
presents thousands  of  seekers  after 
knowledge  whereas  the  technicians  barely 
number  hundreds. 

Get  to  work  on  the  Model  H  and  see 
what  your  results  will  be.  Then  cuss  or 
praise    us   for    starting   this    series;    but 


above  all,  keep  your  eyes  peeled  for  the 
January  number. 

Console  Model 

In  the  beginning  we  contemplated 
making  up  the  model  in  the  console  form 
and  with  this  in  view  we  secured  the 
phone  unit  and  tone  chamber,  the  former 
from  the  American  Electric  Co.,  and  the 
latter  from  Seaman  Jones  Co.  On 
account  of  the  press  of  time  it  was 
impossible  to  make  up  the  console  model 
and  as  a  consequence  We  are  showing  it 
in  the  cabinet  type.  The  builder  of  the 
set  may  use  his  own  discretion  and  if  the 
set  is  to  be  used  for  show  purposes  in 
the  home  it  might  not  be  a  bad  idea  to 
convert  it  into  a  console  model  by  slip- 
ping the  panel  into  one  of  the  regular 
consoles  and  making  arrangements  for 
the  built  in  loud  speaker  to  be  used 
instead  of  the  separate  speaker. 

New  Base  Tubes 

Another  point  which  may  be  of  interest 
to  owners  of  the  neutrodyne  type  of  re- 
ceivers is  the  fact  that  with  the  newer 
issues  of  bases  on  tubes  the  capacity 
between  elements  seems  to  have  been 
reduced  compared  to  the  value  obtained 
when  a  metallic  shell  was  used  for  the 
tube's  lower  housing.  This  has  made  a 
change  in  the  operation  of  some  of  the 
neutrodynes  on  account  of  the  neutro- 
dons  being  larger  in  capacity  than  the 
value  of  the  inter-element  capacities,  and 
as  a  consequence  it  has  been  hard  to  get 
good  neutralization. 

In  the  Model  set  the  tubes  used  were 
of  the  insulating  base  type  and  the  vari- 
able balance  feature  introduced  by  the 
use  of  the  twin-resistor  made  the  compen- 
sation a  simple  matter.  This  difficulty 
may  have  attracted  the  attention  of 
neutrodyne  owners  or  it  may  have  passed 
unnoticed,  but  anyway  there  is  a  differ- 
ence between  the  two  types  of  bases  if 
you  care  to  make  the  tests  on  them. 

Pep  Up  Tubes 

We  have  always  found  that  the  proper 
way  to  find  a  poor  tube  is  to  put  a  bunch 
of  tubes  into  a  set  and  try  to  tune  it.  If 
you  are  using  new  tubes  you  will  not  en- 
counter this  difficulty,  but  if  using  a 
number  of  tubes  which  have  seen  service 
ten  chances  to  one  that  one  of  the  lot  will 
be  a  drone  and  should  be  pepped  up.  For 
that  reason  we  made  use  of  the  Jefferson 
tube  rejuvenator  and  found  one  tube 
which  had  been  bad  merely  needed  a  lit- 
tle treatment  at  the  hands  of  the  rejuve- 
nator to  be  in  good  condition  for  another 
siege  of  long  hours.  Also  swap  your  tubes 
around  in  the  receiver.  Theoretically  . 
this  should  not  be  necessary  if  all  tube 
constants  are  the  same  but  nevertheless 
there  is  generally  enough  variation  in 
tubes  so  this  practice  is  warranted.  The 
detector  tube  in  the  outfit,  if  of  the  soft 
variety,  is  the  only  one  which  will  pull 
more  ampereage  than  the  rest;  the  others 
are  the  quarter  ampere  type.  If  your  A 
battery  happens  to  be  low  put  it  on 
charge  for  a  while,  the  General  Electric 
Tungar  being  a  sturdy  and  efficient  recti- 
fier of  the  bulb  type,  probably  the  first 
on  the  market  years  ago  for  battery, 
stations  before  the  great  wrave  of  radio 
popularity  engulfed  this  world  of  ours^ 


RADIO  AGE /or  December,  1925 


The  Magazine  of  the  Hour 


15 


5EC0NDARY  TUNING  ROD 


6   6    6    6»"  6 

Ft  CURE  J 
Ci/fCUiT    D//9Gff#M    Vf    6AN6    COAtT/?OLL£D    &£C£/V£#- 


L.5. 


42L-JLL 


A  Receiver  that  Employs 

Inductive  Gang  Control 

liHow  Simple  is  Tuning?"  Answered 
Satisfactorily  With  This  Unique  System 


THE  method  of  tuning  a  receiving 
set  is  by  far  the  most  important 
feature  to  the  broadcast  listener 
of  today.  With  the  maze  of  broadcasting 
stations  on  the  air,  it  has  developed  into 
a  science  to  be  able  to  select  what  one 
wants,  when  he  wants  it;  in  fact,  it  is 
impossible  for  some  to  successfully 
operate  the  usual  type  of  set  employing 
several  controls,  which  are  necessary  in 
the  ordinary  run  of  receiving  sets. 

In  the  selection  of  a  manufactured 
receiving  set,  or  in  deciding  upon  a 
set  to  build,  the  prospective  broadcast 
listener  first  asks,  "How  simple  is  the 
tuning?"  and  as  a  secondary  matter,  he 
inquires  as  to  how  far  it  will  reach  out 
and  reproduce  the  distant  signals.  Dis- 
tant reception  seems  no  longer  to  be  the 
prime  factor  in  an  evening's  entertain- 
ment for  the  vast  majority  of  fans.  It 
is  only  the  more  recent  addicts,  or  the 
dyed-in-the-wool  fan,  who  want  to  sit 
up  all  night  listening  to  static,  with  a 
few  occasional  strains  of  sound  caused 
by  music  a  few  thousand  miles  away,  to 
hear  someone  announce  that  "This  is 
station  2  S-S-S-T-k-  broadcasting  from 
their  studio  in  SCRATCH,  bzzz,  bla," 
and  then  complete  silence,  a  frantic 
twisting  of  the  dials  with  more  static, 
failing  to  get  them  back  again,  then  to 
hear  a  faint  signal  and  sit  and  listen  to 


By  H.  FRANK  HOPKINS 

an  ear-straining,  long,  tiresome  lecture 
on  the  effect  of  the  snow-shoe  crop  in 
Hawaii,  to  find  that  it  is  only  a  harmonic 
on  one  of  the  local  stations. 

The  Latest  Trend 

'  I  ''HE  general  trend  of  the  public  is  toward 
-*-  one  or  two-dial-controlled  receivers 
where  the  tuning  is  as  simple  as  possible; 
a  set  that  may  be  logged  so  that  every 
member  of  the  family  can  tune  in  a 
program  as  easily  as  putting  a  record 
on  the  phonograph  in  the  old  days,  with 
somewhere  near  the  same  degree  of 
selection. 

To  meet  this  demand,  a  circuit  has 
been  developed  which  utilizes  gang 
control  effectively.  This  receiver,  to  a 
certain  extent,  resembles  the  old  vari- 
ometer, or  tuned  inductance  type  of 
selection;  that  is,  the  receiver  is  tuned 
by  varying  the  inductance,  rather  than 
the  capacity  of  the  radio  frequency 
stages  as  is  customary  with  the  majority 
of  receivers.  It  embodies  tuned  radio 
frequency  amplification  and  has  five 
tubes,  which  seems  to  be  the  most 
popular  size  of  receiver  at  the  present 
time. 

In  tuning  by  varying  the  inductance, 
it  is  possible  to  adjust  each  unit  to 
resonance  by  using  semi-variable  con- 
densers   shunted    across    the    secondary 


coils  of  the  radio  frequency  and  detector 
couplers. 

These  condensers  are  placed  in  the 
assembly  of  the  completed  receiver  so 
they  may  be  adjusted  as  required,  but 
when  once  set,  they  need  not  be  changed, 
except  when  a  different  length  antenna 
is  used.  This  will  bring  the  filter  qualities 
of  each  unit  into  resonance  with  the 
others  and  by  changing  the  inductance 
of  the  secondaries  of  the  couplers,  each 
will  be  accurately  set  to  pass  signals  of 
a  given  frequency,  by  moving  them  all 
to  the  same  degree,  making  it  possible 
to  use  gang  control  without  the  usual 
vernier  adjustments  on  each  unit. 

The  couplers  used  in  this  circuit  re- 
semble the  usual  form  of  coupler  used 
in  the  detector  circuit  of  the  three 
circuit  regenerative  type  receiver  except 
the  windings  are  different.  The  primaries 
are  wound  upon  a  tube  or  shell  four  in- 
ches in  diameter  and  about  three  inches 
in  length.  A  part  of  the  secondary  coil  is 
also  wound  upon  this  same  tube,  or  shell. 
This  part  of  the  secondary  has  nine  taps 
brought  out,  which  are  connected  to  a 
tapped  inductance  switch.  A  three 
inch  tube,  or  shell,  one  and  one  half 
inches  in  length,  is  then  used  for  the 
balance  of  the  secondary  coil  and  this  is 
placed  inside  of  the  four  inch  tube,  or 
shell,    so   that   it    will   revolve   freely   in 


16 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


an  arc  of  about  160  degrees.  Three  of 
such  couplers  are  used  in  this  receiver 
and  are  shown  designated  RF1,  RF2  and 
DC,  in  the  circuit  diagram,  Figure  one. 

The  taps  from  the  secondary  coil  of 
each  coupler  are  then  connected  to  a 
nine  point  inductance  switch  and  the 
three  switches  are  so  mounted,  that  a 
rod,  or  lever  will  move  each  switch  from 
one  point  to  another  simultaneously  by 
the  operation  of  a  dial  or  knob  on  the 
front  panel  of  the  receiver. 

Mounting  the  Couplers 

THE  three  couplers  are  mounted  into 
the  completed  set  so  a  rod,  or  lever, 
may  be  fastened  to  the  three  inch  diameter 
tubes  or  rotors,  as  they  are  named,  of 
each  unit.  This  rod,  or  lever  is  gear- 
connected  to  a  dial  or  knob  on  the  front 
panel  of  the  receiver  and  by  changing 
the  position  of  the  dial  setting  each 
rotor  is  moved  to  the  same  degree  or 
angle  from  the  outer  shells  or  stator  of 
the  units. 

The  usual  form  of  detector  circuit  is 
used  in  this  receiver;  it  is  non-regenera- 
tive, as  regeneration  or  feed-back  of  the 
detector  tube  would  make  it  impossible 
to  bring  the  coupler  DC  into  resonance 
with  the  others.  Two  stages  of  trans- 
former coupled  audio  amplification  pro- 
vide volume  enough  to  operate  the  loud 
speaker  on  all  signals.  The  tubes  of 
this  receiver  are  controlled  by  two  rheo- 
stats and  two  automatic  filament  control 
devices.  The  radio  frequency  amplifier 
tubes  are  both  controlled  by  the  six 
ohm  rheostat  R,  the  detector  tube  is 
controlled  by  the  twenty-five  ohm  rheo- 
stat D  and  each  audio  amplifying  tube 
has  a  separate  automatic  filament  con- 
trol which  does  not  require  the  operator's 
attention. 

Two  radio  frequency  choke  coils  are 
placed  into  this  circuit  for  the  purpose  of 
keeping  the  radio  frequency  currents 
from  by-passing  to  the  detector  tube 
through  the  batteries  of  the  receiver. 
These  coils  are  shown  in  the  circuit  dia- 
gram, Figure  one,  as  RC1  and  RC2. 


The  panel  layout  for  this  type  of  re- 
ceiver is  shown  in  Figure  2,  and  will 
more  readily  show  the  simple  tuning 
operation  required.  At  the  extreme  left 
of  the  panel  is  shown  a  dial  pointer. 
This  dial  and  pointer  controls  the  rod 
or  lever  which  moves  the  inductance 
swi+ches  from  one  contact  to  another. 
When  the  pointer  is  on  the  200  mark, 
the  inductance  switches  will  all  be  on 
the  first  contact.  This  should  roughly 
tune  the  secondaries  of  the  three  couplers 
to  pass  signals  in  the  wavelength  band 
of  from  200  to  250  meters  and  is  what  we 
will  call  primary  tuning.  The  steps 
on  this  adjustment  will  vary  the  tuning 
of  the  receiver  in  bands  of  fifty  meters, 
ranging  from  200  meters  to  600  meters. 

At  the  extreme  right  of  the  panel  will 
be  found  a  100-point  dial,  which  is  the 
fine  tuning,  or  secondary  tuning  adjust- 
ment of  the  receiver.  This  dial  con- 
trols the  rotors  of  the  three  couplers,, 
thus  varying  the  inductance  of  the  coils 
so  the  units  will  be  tuned  throughout  the 
wavelength  bands,  or  steps  of  fifty  meters. 
A  100  point  scale  is  used  so  it  will  be 
direct  reading,  each  division  representing 
one  half  of  a  meter  above  the  reading 
of  the  primary,  or  rough  tuning  dial. 
This  feature  makes  it  very  easy  to  log 
the  set  or  locate  a  station  whose  wave- 
length is  known. 

Locating  Stations 

nPO  FIND  a  station  whose  wavelength 
-*-  is  known,  and  all  station  wave- 
lengths are  published  along  with  their 
daily  schedule  of  broadcasting,  in  most 
of  the  daily  papers  and  radio  publica- 
tions, it  is  only  necessary  to  move  the 
two  dials  to  correspond  with  the  number 
of  meters,  as  follows;  To  tune  in  a 
station,  say  KYW  at  Chicago,  whose 
wavelength  happens  to  536  meters,  the 
left  hand  pointer,  or  primary  tuning 
control  would  be  put  on  the  500  marking 
and  the  right  hand  dial  or  secondary 
tuning  control  would  be  revolved  to  the 
setting  of  seventy-two.  This  should  tune 
the  set  to  the  wavelength  of  536  meters. 


To  tune  in  a  station  whose  wavelength 
is  in  the  lower  band  of  frequencies,  say 
WLS  at  Chicago,  which  happens  to 
be  344  meters  the  rough,  or  primary 
tuning  dial  would  be  set  at  300  and  the 
fine,  or  secondary  tuning  dial  would  be 
set  at  eighty-eight,  thus  making  a  total 
of  344  meters,  as  each  division  on  the 
secondary  tuning  control  scale  is  equal 
to  one  half  meter. 

Tuning  such  as  this  eliminates  the 
necessity  of  wavemeters,  tuning  charts, 
etc.  and  provides  a  scale  reading  so  that 
one  can  readily  pick  out  the  different 
stations  without  guess-work.  The  scale 
readings  on  the  model  set  were  accurate 
to  one  half  meter. 

The  semi-variable  condensers  of  the 
set  are  three  in  number,  one  for  each 
coupling  unit.  They  are  shown  in  the 
circuit  diagram,  Figure  1,  as  CI,  C2 
and  C3.  These  condensers  are  adjusted 
so  the  coupler  associated  with  it  is  in 
resonance  with  the  other  couplers  when 
the  set  is  being  worked  on  an  antenna  of 
the  same  length  as  was  used  to  adjust  the 
set.  The  condensers  may  eisily  be  adjust- 
ed by  tuning  the  set  to  a  given  wave 
length,  such  as  KYW,  at  a  dial  setting 
of  572.  The  condensers  will  then  be  moved 
to  a  position  where  the  signal  is  at  its  maxi- 
mum volume.  This  may  be  checked  by 
retuning  the  set  to  a  lower  wavelength 
station,  say  WIBO  at  Chicago,  whose 
wavelength  is  216.5  meters;  the  dial 
settings  would  be  233.  If  the  result  is 
slightly  off  color,  re-adjust  the  three 
condensers  until  the  signal  is  brought  in 
at  its  maximum  volume  and  then  turn 
the  dials  back  to  the  original  setting  for 
the  higher  wave  station.  If  the  signal 
is  satisfactory  at  this  setting,  the  set 
will  be  balanced  and  each  tuning  unit 
will  be  in  resonance  with  the  others 
The  condensers  need  not  be  again  ad- 
justed until  the  length  of  the  antenna  is 
changed.  If  the  adjustment  is  a  little 
off  color  yet,  tune  to  a  station  of  about  300 
and  set  the  condensers,  readjusting 
them  again  at  the  high  and  low  wave- 
lengths until  a  good  average  is  obtained. 


PR! 


001  VV         )] 


SW. 


SEC. 


L.S. 


PAN£L    lAYOt/r  OF    G/M6    COAtr*OLL£0  rrC£/\/£/F. 
0/41 S    fiJPS    SST    TO    SHOW      3£T      Ti/A/£0     FO/?     ti 
W/9VSLSHGTH     OF    S3&  MSTS&S*  M 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour  17 


Making  Radio  for  QUALITY 


The  living 
room  of  Francis 
W.  Dun  more 
in  Washington, 
D.  C,  in  which 
it  is  only  nec- 
cessary  to  press 
a  button  and 
radio  entertain- 
ment  issues 
forth  from  the 
cone  loud 
speaker  shown 
in  the  photo. 
Buttons  in- 
stalled in  each 
room  make  in- 
stant reception 
an  easy  matter. 


Unique  Receiver  for  Providing  Radio 
"Outlets"  in  Any  Part  of  Your  Home 


RADIO  for  the  Home,"  is  no  mere 
platitude  or  catch  phrase  with 
Francis  W.  Dunmore  of  the 
Radio  Laboratory  of  the  Bureau  of 
Standards.  He  has  not  only  designed 
and  built  a  radio  receiving  set  distin- 
guished for  its  tonal  quality,  but  has  pro- 
vided outlets  for  reception  of  music  and 
speech  at  seven  points  throughout  his 
residence — cellar,  sun  porch,  living  room, 
bedroom,  sewing  room,  radio  laboratory, 
and  kitchen. 

When  at  least  one  radio  broadcasting 
station  is  entitled  to  the  classification  of 
"super-power"  and  a  dozen  or  more  sta- 
tions are  increasing  their  use  of  power 
appreciably,  the  radio  receiving  outfit 
of  Mr.  Dunmore  invites  special  atten- 
tion by  reason  of  the  designer  placing 
emphasis  on  quality  of  reproduction  of 
music  and  speech.  For  instance,  with 
WGY  of  Schenectady  using  50  kilowatts 
in  the  transmitter  and  with  nearly  600 
broadcasting  stations  in  operation,  this 
radio  receiver  can  be  built  and  used  with 
pleasure  by  thousands  of  fans  who  are 
forsaking  "DX"  feats  for  quality  music 
and  speech.  The  approaching  winter, 
with  a  great  many  nearby  stations 
"on  the  air,"  will  find  the  "DX"  tribe 
decreasing  in  numbers  and  the  recruits 
to  quality  reproduction  multiplying. 

This  radio  receiver,  distinguished  for 
its  tonal  quality,  does  not  involve  any 
radically   different  electrical  principle  or 


BY  S.  R.  WINTERS 

trick  circuit.  It  is  different  from  the 
conventional  type  of  equipment  to  the 
extent  of  being  a  reactance  instead  of  a 
transformer-coupled  amplifying  unit,  but 
this  is  not  new  to  radio  engineers.  Mr. 
Dunmore,  however,  has  made  one  de- 
parture and  to  this  may  be  attributed,  in 
part,  his  success  in  developing  an  ideal 
receiver  for  use  in  receiving  programs 
of  local  or  nearby  broadcasting  stations. 
Condensers  are  shunted  across  the  second- 
aries of  the  audio-frequency  transform- 
ers. These  transformers  are,  however, 
not  used  as  transformers,  but  the  second- 
aries are  employed  as  chokes.  This 
arrangement  seems  to  fit  in  admirably 
with  the  use  of  a  cone-type  loud  speaker, 
which,  of  course,  helps  materially  in 
quality  reproduction.  The  circuit  dia- 
gram reproduced  with  this  article  illus- 
trates the  manner  of  connection. 

A  crystal  detector  and  three  vacuum 
tubes  as  amplifiers  are  employed  in  this 
outfit,  two  of  the  latter  being  UV-201A 
and  the  third  216A,  The  primary  tuning 
device  consists  of  a  home-made  variometer, 
actually  constructed  from  paper  boxes 
formerly  containing  oatmeal  and  hominy. 
The  rotating  element  of  this  homespun 
variometer  consists  of  a  hominy  box,  on 
which  is  wound  40  turns  of  fine  copper 
wire.     The  stator  or  stationary  unit  of 


this  unique  tuning  device  consists  of  an 
oatmeal  box,  and  to  add  to  the  complete- 
ness of  its  odd  makeup,  an  ordinary  5- 
cent  pencil  is  used  as  the  shaft  for 
adjusting  the  rotating  element  of  the 
variometer  for  tuning  purposes.  When 
more  selectivity  is  needed  a  coupled 
crystal  circuit  may  be  used.  As  there  is 
but  one  local  station  on  the  air  at  a 
time  in  Washington,  a  selective  crystal 
circuit  is  not  needed.  Of  course,  if  the 
broadcast  listener,  contemplating  the 
building  of  this  radio  receiver,  is  lacking 
in  such  cleverness  of  design,  he  will  find 
that  a  commercial  type  of  variometer 
will  answer  the  same  purpose.  By  the 
use  of  a  crystal  set  the  distortionless 
crystal  quality  is  put  into  the  amplifier, 
which  in  turn  is  faithfully  reproduced. 

.005  Condensers  Used 

AS  PREVIOUSLY  stated,  condensers 
of  .005  microfarad  capacity  are 
shunted  across  the  secondary  windings 
of  the  two  audio-frequency  transformers. 
Three  grid  leaks  are  used  of  varying 
resistances —  .1,  .25,  and  .5  megohm, 
respectively.  The  power  consumption  of 
the  third  or  output  vacuum  tube,  type 
216A,  is  greater  than  that  of  the  UV-201 A 
tubes,  the  former  consuming  one  ampere. 
This  tube  seems  to  be  ideally  adapted  to 
this  particular  type  of  loud-speaker,  al- 
though it  is  not  absolutely  necessary. 
(Turn  the  page) 


18  RADIO  AGE /or  December,  1925 


The  Magazine  of  the  Hour 


A  close-up  view  of  the  ideal  type  of  radio  receiver  for  receiving  music  or  speech  from  local  broadcasting  stations.  A  crystal  de- 
tector (not  shown  in  the  picture),  is  used,  and  two  types  of  vacuum  tubes —  UV201A  and  216 A.  Condensers  are  shunted  across 
the  secondary  of  the  audio-frequency  transformers.      The  circuit  is  of  the  impedance  coupled  type,  using  a  cone  type  loud  speaker. 


An  80-ampere-hour  storage  battery  is 
used  for  lighting  the  filaments,  and  the 
use  of  an  electrolytic  type  of  battery 
charger  renders  it  possible  to  charge 
the  battery  while  the  radio  receiver  is 
operating  without  experiencing  any  dis- 
turbing effects.  The  reader  is  cautioned 
not  to  charge  while  using  unless  he  is 
familiar  with  his  charger  circuit. 

By  means  of  two  fine  wires,  run 
parallel,  Mr.  Dunmore  has  conveniently 
placed  outlets  for  the  music  or  speech 
intercepted  by  this  receiver  at  seven 
places  throughout  his  residence.  That 
is  to  say,  if  he  happens  to  be  in  the  cellar, 
sun  porch,  living  room,  bedroom,  sewing 
room,  radio  laboratory,  or  kitchen,  he 
can  connect  the  loud-speaking  cone  to 
an  outlet  and  music  or  speech  will  issue 
forth,  provided  a  local  broadcast  station 
is  operating.  For  instance,  upon  en- 
tering his  front  door  a  button  can  be 
pressed  and  speech  or  music  heard  within 
less  than  half  a  minute.  In  less  time 
than  that,  he  can  increase  or  decrease 
the  value  of  the  sound  by  means  of  a 
shunt  resistance  which  he  places  across 
the  parallel  wires  extending  from  the 
radio  receiver  located  in  his  radio 
laboratory  on  the  second  floor.  Develop- 
ing this  extension  system  a  bit  further, 
his  neighbor  can  hear  a  concert  by 
simply  attaching  a  loud-speaking  device 
to  the  extension  wires  running  from  the 
residence  of  Mr.  Dunmore. 

If  you,  as  a  broadcast  listener,  are 
obsessed  with  the  itch  for  distance,  the 
radio  receiver  outlined  in  this  article 
cannot  be  expected  to  meet  your  re- 
quirements. If,  however,  you  are  one 
of  the  increasing  multitude  who  appraises 
radio  apparatus  but  as  an  instrumentality 
to  enjoyable,  uninterrupted  entertain- 
ment or  worthwhile  instruction  dispersed 
from  nearby  broadcasting  stations  this 
homemade  outfit  will  furnish  unalloyed 
pleasure.  The  cost  need  not  be  exces- 
sive— the  kit,  excluding  vacuum  tubes, 
batteries  and  loud  speaker,  costing  less 
than  $25.00.  The  cone  type  of  loud 
speaker,  of  very  modern  design,  represents 
the  most  costly  single  item. 

This  writer  has  heard  many  types  of 
receiving  equipment,  expensive  and  other- 
wise, and  I  can  state  without  qualifica- 
tions that  the  music  emanating  from  this 
homemade  set,  using  a  cone  type  loud 
speaker,    comes   nearer  approaching   the 


ideal  than  any  I  have  heard.  Of  course, 
it  places  a  potential  value  on  programs 
broadcast  from  nearby  stations  and 
ignores  the  "DX"  radio  fan  who  prefers 
a  squeal  coming  from  a  distance  of  2,000 
miles  to  the  soft,  inspiring  strains  of 
music  having  their  source  only  a  few 
miles  distant.  This  receiver  and  similar 
designs  in  the  interest  of  delivering  tonal 
quality  may  be  indicative  of  a  not  re- 
mote future  when  radio  will  assume  its 
destined  important  role  of  universal 
entertainer  and  educator  instead  of 
being  made  a  victim  of  squeals,  howls, 
and  figurative  cat  calls. 

Home  Talent  First 

r  I  ^HE  humorist  who  cartooned  a  radio  fan 
-*-  listening  to  a  gnat  sneeze  in  Hawaiian 
Islands  in  preference  to  hearing  Grand 
Opera  in  Chicago  was  expressing  in  ludi- 
crous terms  the  viewpoint  of  the  DX 
broadcast  listener.  And,  not  so  long 
ago  this  desire  for  distance  at  any  cost 
found  expression  in  any  army  of  radio 
fans.  To  "get  the  coast"  was  the  ulti- 
mate achievement  of  "DX  hounds"  of 
the  East  and  those  of  the  West  probably 
were  seeking  to  "get  New  York  City." 

The  distance  craze,  however,  is  subsid- 
ing somewhat,  an  evidence  of  which  is 
the  absence  on  radio  pages  of  newspapers 
and  in  radio  magazines  of  the  long  list  of 
"calls  heard"  and  stations  logged.  If 
resistance-coupled  amplifiers  and  cone 
types  of  loud  speakers  are  to  be  accepted 
as  a  criterion,  the  broadcast  listener  of 
the  future  will  challenge  his  neighbor  radio 
fan  in  this  manner:  "I  heard  every  note 
of  the  orchestra  last  night,  faithful  in 
reproduction.  It  was  like  listening  to 
music  in  your  own  home.  Can  you 
beat  it?" 

Francis  W.  Dunmore  of  the  Radio 
Laboratory  of  the  Bureau  of  Standards, 
both  in  theory  and  practice,  is  a  distin- 
guished exponent  of  quality  in  radio 
programs  in  preference  to  distance, 
merely  for  the  sake  of  annihilating  space. 
You  would  probably  surmise  that  this 
brilliant  radio  engineer  would  possess 
an  8  or  even  16  tube  radio  receiving  set. 
Instead,  however,  he  has  designed  and 
built  a  receiver  purely  adapted  to  local 
reception  and  where  increased  power  is 
used  at  the  transmitting  station,  he 
could  probably  pick  up  signals  from 
KDKA  or  WGY. 


This  radio  receiving  set  was  designed 
and  built  by  Mr.  Dunmore  during  his 
spare  hours,  when  off  duty  as  a  member 
of  the  staff  of  the  Radio  Laboratory  of 
the  Bureau  of  Standards.  Some  of  the 
parts  are  homemade — for  instance,  the 
tuning  device — and  every  instrument  is 
put  together  with  the  single  objective  of 
possessiong  a  radio  receiver  distinguished 
for  the  reproduction  of  tonal  quality  in 
music  and  the  clear,  unmuffled  words  of 
a  speaker.  This  objective  he  has  accom- 
plished in  no  small  measure. 

Room  For  All 

There  will  always  be  room  for  two  types 
of  receivers,  just  as  there  is  room  for 
more  than  one  kind  of  automobile, 
shaving  brushes  and  clothes.  There  is 
a  definite  class  of  listeners  who  care 
nothing  for  the  music  emanating  from 
a  source  further  than  their  local  horizon, 
individuals  of  a  temperament  which 
will  not  permit  their  constant  fiddling 
and  tinkering  to  obtain  long  distance  re- 
ception. This  type  of  listener  wants  his 
music  loud  and  clear,  the  emphasis  on  the 
clear.  He  probably  feels,  and  rightly  so, 
the  local  broadcast  will  serve  him  with 
everything  he  desires  in  the  line  of  enter- 
tainment, the  quality  of  which  may  be 
fully  as  good  as  the  type  of  entertainment 
being  broadcast  from  a  thousand  mile 
station. 

On  the  other  hand  there  is  the  insa- 
tiable fan  who  must  have  distance  at 
all  costs  and  who  by  nature  is  never 
content  with  a  simple  set  which  may  be 
turned  on  by  merely  pressing  a  button. 
Late  hours  and  a  loss  of  sleep  mean  noth- 
ing to  him;  his  prime  object  in  life  is  the 
accumulation  of  a  list  of  distant  stations 
which  he  may  exhibit  with  pride  to  his 
neighbors  and  friends.  While  he  may 
tolerate  the  local  broadcasting,  neverthe- 
less he  feels  he  would  like  to  reach  beyond 
the  rim  of  the  teacup  and  find  out  what 
is  going  on  out  in  the  wide  world.  Both 
types  of  listeners  are  necessary  to  the 
advance  of  the  game.  The  first  type, 
demanding  stability,  ease  of  operation, 
tone  quality; the  latter  asking  distance- 
getting  and  selectivity.  The  manufac- 
turers have  two  fields  before  them  in  the 
construction  of  sets,  all  lending  variety 
and  making  for  changes  in  equipment  to 
satisfy  the  demands  of  the  two  camps  of 
listeners. 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


A  Favorite  for  DX — 

Tuned  RF  and  REGENERATION 


19 


IN  THE  wake  of  the  five  tube  tuned 
R.  F.  set  comes  another  aspirant  for 
long  distance  honors — one  which  has 
been  slowly  coming  into  popularity  in 
the  past  six  months  and  is  now  widely 
favored.  It  is  a  simple  union  of  tuned 
radio  frequency  and  regeneration  and  has 
the  following  distinguishing  points: 

1.  Two  tuning  controls. 

2.  Regeneration — permitting  tuning  in 
by  the  "whistle." 

3.  Neutralized  R.  F. — preventing  ra- 
diation and  R.  F.  oscillation. 

4.  Uniform  sensitivity  over  the  en- 
tire wave  range. 

The  use  of  regeneration  has  two  marked 
advantages  besides  the  close  control 
over  the  sensitivity.  In  the  first  place, 
the  faintest  station  can  be  located  on  the 
dial  by  permitting  the  detector  to  oscil- 
late, by  the  carrier  or  "whistle."  Again, 
the  tuning  in  the  detector  circuit  is 
greatly  sharpened  by  regeneration,  there- 
by making  the  circuit  just  as  sharp  as 
that  of  a  three  control  set  like  the  neu- 
trodyne  or  other  tuned  R.  F.  having 
two  stages  of  radio  frequency.  And  the 
tuning  is  confined  to  two  controls — an 
important  simplification.  Of  course,  the 
whistle  system  of  tuning  would  be  a 
nuisance  were  it  carried  on  with  a  regular 
regenerative  set,  but  with  a  neutralized 
R.  F.  tube  ahead  of  it,  no  radiation  can 
occur.  Moreover  the  R.  F.  augments  the 
incoming  signals  a  lot  and  sharpens  the 
tuning  besides. 

Uniformity  in  amplification  is  obtained 
by  the  regenerative  control,  wherein 
greater  coupling  is  required  as  the  wave- 
length increases.  Here  is  the  biggest 
fault  with  the  three  control  tuned  R.  F. 
outfit.  Of  course,  the  latter  can  have  a 
regeneration  or  sensitivity  control,  but 
this  is  somewhat  troublesome  where  there 
are  three  tuning  dials  already. 

Many  Kinds  of  This  Type 

THERE  are  numerous  forms  of  this 
popular  circuit.  The  information  pre- 
sented here  should  be  of  interest  to  those 
already  having  such  an  outfit,  as  well  as 
to  others  interested  in  it.  In  the  small 
sketch  we  present  a  sample  arrangement 
of  the  panel,  which  should  measure  about 
7  by  24  inches.  It  can  be  assembled  on  a 
smaller  panel,  with  a  little  care,  too. 
The  controls  shown  cover  the  needs  of  the 
ideal  receiver — 

1.  Ability  to  tune  to  the  desired  sta- 
•  tion. 

2.  Sensitivity. 

3.  Selectivity. 

The  tuning  controls  shown  tune  the 
radio  frequency  and  detector.  The 
tickler  controls  the  sensitivity  and  inci- 
dentally the  volume.  Although  with  a 
nominal  degree  of  coupling  the  selectivity 
will  be  good,  on  account  of  the  two  tuning 
controls  and  the  regenerative  detector,  a 
variable  coupling  is  highly  useful.  The 
coupling   control    at   the   left    permits   a 


By  BRAIN ARDFOOTE 

Stations  Missed 
in  RF  Sets  Picked 
Up  by  the  Whistle; 
Distance   Improved 

variation  in  the  selectivity — a  feature 
most  valuable  for  high  and  low  Waves. 
On  wavelengths  under  250  meters,  a 
reduction  in  coupling  by  using  fewer 
turns  in  the  antenna  primary  coil  lowers 
the  natural  period  of  the  aerial  and  sharp- 
ens up  the  tuning.  On  long  waves,  it  is 
of  great  help  to  use  a  larger  antenna  pri- 
mary coil.  A  coupling  variation  with 
three  adjustments  is  most  helpful  all 
around.  It  upsets  the  dial  readings  of 
the  R.  F.  dial  slightly,  but  since  those  of 
the  detector  dial  are  unaffected,  these 
dial  readings  are  used  for  "logging." 

To  permit  the  use  of  headphones  for 
DX  listening,  a  jack  is  provided  for  this 
purpose.  This  is  a  filament  control  jack, 
which  automatically  turns  off  the  second 
audio  amplifier  tube.  The  loud  speaker 
cords  are  permanently  connected  to 
binding  posts.  Rheostats  or  filament 
resistors  are  placed  inside  the  set,  since 
they  may  be  adjusted  once  and  left 
alone.  A  snap  switch  in  the  "A"  battery 
circuit  turns  the  set  on  and  off. 

Parts  in  Use 

T^HE  panel  lay-out  suggested  is  that 
-*-  used  by  the  writer  and  preferred  be- 
cause of  its  convenience  and  handiness. 
As  to  the  parts  employed  in  the  receiver, 
considerable  latitude  of  choice  is  permit- 
ted. There  is  no  especial  type  of  coil  or 
condenser  necessary,  although  these  tun- 
ing instruments,  being  the  very  essence 
of  the  set,  should  be  of  the  highest  quality. 
Standard  couplers  may  be  used,  many 
companies  providing  two  types — one 
with  a  tickler  and  one  without,  otherwise 
the  same.  The  coils  ought  to  be  on  a 
skeletonized  frame  and  if  they  are  space- 


XOUf  LING         v  TICKLER    PHONES 


BAT.       Tuning 

5  WiTCH 


A  sample  panel  lay-out,  arranged  for 
neatness,  balance  and  convenience.  The 
coupling  adjustment  permits  a  variation 
in  selectivity. 


wound,  that  is  with  an  air  space  between 
turns,  so  much  the  better.  A  low-loss 
condenser,  of  the  straight  line  wavelength, 
or  still  better,  of  the  straight  line  fre- 
quency type  should  be  employed  for 
tuning.  To  make  the  dials  agree  fairly 
well,  coils  should  be  of  the  same  design, 
as  well  as  the  condensers.  In  selecting  a 
straight  line  frequency  condenser,  care 
must  be  taken  to  note  the  action  and 
balance,  as  such  instruments,  while 
theoretically  best  for  easy  and  uniform 
tuning,  are  apt  to  be  unsound  mechani- 
cally. Adjustable  bearings  are  essential, 
to  compensate  for  friction.  Good  vernier 
dials  are  pretty  important  as  it  is  hard  to 
set  a  non-vernier  dial  just  right  for  so 
selective  a  receiver,  except  perhaps  for 
locals. 

The  remainder  of  the  apparatus  is  of 
lesser  importance.  Sockets  should  be 
chosen  to  fit  the  types  of  tube  desired. 
Best  results  are  obtained  with  quarter 
ampere,  6  volt  tubes  in  the  detector  and 
audio  sockets  and  either  the  199  type  or 
the  quarter  ampere  6  volt  type  in  the 
R.  F.  Some  claim  better  results  for  the 
199  as  the  radio  frequency  tube,  but 
there  is  some  doubt  about  this.  At  any 
rate,  it  is  preferable  to  use  the  socket 
meant  for  the  chosen  tube  and  avoid 
adapters.  The  circuit  given  considers 
quarter  ampere  6  volt  tube  throughout. 

The  neutralizing  condenser  may  be 
one  of  the  "vernier"  variables,  or  a 
regular  neutrodon.  A  good  neutralizing 
condenser  of  the  XL  type  is  adjusted  by 
a  screw.  Grid  condenser  and  leak  are 
combined  in  one  and  have  capacity  of 
about  .00025  mfds.  and  resistance  of 
about  2  megohms,  respectively.  A  .001 
or  .002  mfds.  by-pass  condenser  is  need- 
ed also.  The  jack  is  the  double  circuit 
filament  control  type.  The  audio  am- 
plifier may  be  coupled  by  transformers, 
resistances  or  chokes,  according  to  pre- 
ference. Transformers  are  indicated 
here.  One  rheostat,  R-l,  controls  three 
tubes  and  has  a  resistance  of  6  to  10 
ohms,  carrying  capacity  of  about  1  am- 
pere. R-2  has  a  resistance  of  15  to  30 
ohms,  carrying  capacity  at  least  \$ 
ampere. 

Connections 

ON  THE  panel  we  have  the  two  variable 
condensers,  the  two  couplers,  if  they 
are  of  the  panel  mounted  type,  the  jack, 
battery  switch,  tickler  knob  and  coupling 
or  selectivity  switch.  The  antenna 
coupler  is  the  one  without  the  tickler.  It 
has  two  windings — primary  and  second- 
ary. Tire  primary  should  have  about 
ten  turns.  This  amount  represents  the 
average  condition  of  coupling  and  is 
connected  to  the  center  of  the  three 
switch  points,  as  shown.  Minimum 
coupling  is  had  with  about  5  turns,  to 
which  the  right  hand  switch  point  is  tap- 
ped. To  make  the  tap,  pry  up  the  turn 
with  a  knife-point,  slip  a  bit  of  mica  or 


20 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


thin  hard  rubber  or  bakelite  under  it 
to  protect  the  adjacent  turns  and  scrape 
the  insulation  off  for  an  eighth  of  an  inch. 
Apply  a  speck  of  flux  and  "tin"  this  bared 
wire.  Tin  the  tap  lead,  too  and  flow- 
both  together  with  the  iron. 

The  "volume"  or  maximum  coupling 
tap,  is  had  by  connecting  the  left  hand 
point  to  a  turn  on  the  secondary  about 
ten  turns  in  from  the  filament  end.  This 
tap  is  similarly  made,  of  course.  Note 
that  coil  1,  the  primary,  has  its  inside 
end  joined  with  the  inside  end  of  coil  2, 
the  secondary,  and  this  point  is  connected 
to  ground  and  to  "A"  minus.  The  detec- 
tor coupler  must  be  mounted  so  that  its 
secondary,  coil  4,  is  on  a  line  but  at  right 
angles  with  the  secondary  of  the  antenna 
coupler,  coil  2.  This  is  a  very  important 
point  and  one  usually  neglected  or  only- 
half  done.  If  any  coupling  exists  between 
these  secondary  coils  it  will  be  impossible 
to  neutralize  the  set  for  all  wavelengths. 
Remember — it  is  not  the  coupler  forms  or 
tubings  which  are  to  be  at  right  angles 
and  on  a  line — but  the  secondary  WIND- 
INGS themselves.  A  useful  mounting 
is  to  locate  the  detector  coupler  in  the 
center  of  the  panel,  up  and  down,  and  to 
fasten  the  antenna  coupler  on  a  bracket 
just  behind  the  coupling  switch. 

Care  must  be  exercised  in  connecting 
up  the  detector  coupler.  If  the  primary- 
coil  has  over  eight  turns,  it  should  be 
cut  down  to  this  figure.  The  leads  to 
the  tickler  coil  are  shown  at  the  top, 
coil  5.  The  primary  winding,  coil  3,  is 
connected  in  a  definite  direction.  If  it 
is  wound  in  the  SAME  DIRECTION  as 
the  secondary,  coil  4,  it  is  imperative 
that  the  plate  of  the  R.  F.  tube  be  connec- 
ted to  the  outside  (bottom)  end  of  the 
primary  and  the  "B"  plus  to  the  inside 
end.  If  this  is  not  done,  it  will  not  be 
possible  to  neutralize  the  set.  The  neu- 
tralizer  tap  is  placed  at  a  point  about 
eight  turns  from  the  filament  end  of 
coil  4,  the  detector  secondary.  Here 
develops  the  reason  for  connecting  coil 
3  what  might  appear  to  be  "upside  down." 

When  the  detector  tube  is  oscillating, 
energy  that  might  be  radiated  from 
aerial  is  picked  up  in  coil  3  from  coil  4. 


Thence  it  passes  to  the  antenna  coupler 
through  the  "plate  to  grid"  capacity  of 
the  tube.  But,  with  a  neutralizing  capac- 
ity N  arranged  in  circuit  to  pick  up 
feed-back  energy  too,  it  is  possible  to 
counteract  the  energy  through  the  tube 
capacity — providing  the  current  in  the 
neutralizing  circuit  is  in  the  opposite 
direction.  The  section  of  coil  4  between 
the  tap  and  the  filament  end  acts  like 
an  independent  coil  so  far  as  this  pick-up 
is  concerned  and  coil  3  must  be  connected 
to  be  opposite  to  it  in  direction.  The 
capacity  of  N  does  not  necessarily  have 
to  be  equal  to  the  plate  to  grid  capacity 
of  the  tube,  but  when  the  tap  is  placed 
so  as  to  have  the  same  number  of  turns 
from  it  to  the  filament  as  in  coil  3,  the 
neutralizing  and  tube  capacities  are 
nearly  the  same. 

The  remainder  of  the  circuit  is  not  out 
of  the  ordinary.  Where  headphone  re- 
ception is  desired,  the  jack  is  placed  to 
provide  access  to  the  first  audio  amplifier 
tube.  At  the  same  time,  filament  current 
is  cut  off  from  the  second  audio  tube  by 
a  special  use  of  the  filament  control 
jack.  The  type  of  jack  shown  is  the 
most  common,  having  five  contact  springs. 
Three  of  these  are  for  filament  switching, 
but  only  two  are  employed  here.  To 
turn  the  set  on  and  off,  a  main  filament 
switch  is  used,  shown  at  S.  C-l  is  the 
R.  F.  tuning  condenser,  C-2,  the  detector 
tuning  condenser,  C-3  grid  leak  and  con- 
denser, C-4  the  by-pass  condenser. 
AFT  signifies  an  audio  frequency  trans- 
former and  the  four  sockets  are  marked 
RF  for  radio  frequency,  DET  for  detec- 
tor, AF1  for  the  first  audio  and  AF2  for 
the  second  audio.  It  is  a  good  stunt  to 
use  the  UX  power  tube  instead  of  the 
regular  201A  or  301A  type  in  the  second 
audio  socket,  as  that  improves  the  loud 
speaker's  quality.  R-l  is  the  rheostat  of 
lower  resistance,  for  three  tubes  and  R-2 
the  rheostat  of  higher  resistance,  for  the 
last  audio  tube. 

Neutralizing 

'  I  ''HE  first  important  step  is  neutralizing 
■*-  the  set.  To  do  this,  tune  in  a  strong 
local    signal    carefully.      Then    open   the 


filament  circuit  of  the  RF  tube  by  placing 
a  piece  of  paper  in  between  the  filament 
prong  of  the  tube  base  and  the  spring 
contact  of  the  socket,  or  else  by  taking 
off  one  of  the  filament  wires.  This  leaves 
the  tube  in  the  socket,  unlighted.  Then 
allow  the  detector  to  oscillate,  when  the 
whistle  of  the  station  will  be  heard. 
Adjust  the  RF  condenser  (C-l)  till  the 
whistle  is  as  loud  as  possible.  The  cur- 
rent enters  to  coil  3  via  the  grid-plate 
capacity  of  the  tube,  which  acts  as  a 
little  condenser.  Next  vary  N  slowly 
until  the  whistle  is  at  its  weakest  point 
or  disappears  altogether.  If  this  weakest 
point  is  not  found,  but  the  whistle  is 
weaker  with  the  neutralizer  at  full  capac- 
ity, move  the  neutralizer  tap  on  coil 
4  up  a  few  turns.  If  the  whistle  is  least 
strong  with  the  neutralizer  at  minimum 
capacity,  move  the  tap  down  towards 
the  filament  end  a  few  turns.  At  the 
"dead  spot,"  which  will  be  very  critical 
on  the  neutralizer,  the  whistle  may 
perhaps  be  heard  through  direct  induc- 
tion on  the  detector  coil  4,  but  the  tuning 
of  C-l  then  has  no  effect  whatsoever  on 
the  whistle.  Now,  when  the  RF  tube 
is  lighted,  no  radiation  will  take  place. 
Try  this  on  several  wavelengths.  If 
the  neutralizer  is  not  adjusted  the  same 
for  all  waves,  there  is  coupling  between 
coils  2  and  4  and  either  one  should  be 
shifted  slightly  until  the  desired  neutra- 
lization is  found. 

It  is  not  only  important  to  neutralize 
in  order  that  no  radiation  occurs,  but 
so  that  the  RF  tube  can't  oscillate  and 
upset  the  adjustment  of  the  tickler.  If 
trouble  is  found  on  low  waves  in  stopping 
oscillation,  there  are  too  many  turns  on 
coil  3  and  some  should  be  removed. 
From  6  to  9  turns  generally  suffice. 

In  tuning,  ordinarily  leave  the  coupling 
switch  at  the  center  point.  The  dials 
will  agree  fairly  closely.  For  local  sta- 
tions, once  the  dial  settings  are  found,  it  is 
unnecessary  to  have  the  detector  oscillat- 
ing to  locate  them.  For  weak  DX  sta- 
tions, however,  the  detector  is  made  to 
oscillate  by  moving  the  tickler  knob 
to  the  clicking  point  and  varying  C-2  to 
find   the   whistle. 


o   o  o   o  o  o  o 

ANT   gnd    a-    a+ 


B-    B*     &f 

DtT.     AIR 


SPtflKER 


Circuit  diagram  of  a  set  having  one  step  of  RF  and  a  regenerative  detector.     This  is  exceedingly  popular  for  DX  reception,  because  of 

its  sharpness,  sensitiveness  and  uniformity  of  amplification  over  the  wave  band.     Properly  neutralized,  it  is  possible  to  use  the 

"whistle'-'  to  find  the  weak  DX  station  without  interfering  with  any  other  listener. 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


21 


r 


Here 

Is  a 
Simple 
Method 

That 

Will 
Improve 

Your 
Tuning 


"TTTTTTTTT" 

<- 

P| 

so 

Station    W.Lin      Dial  Settings 
Letters   Meters    Ma/  No.2  hlo.3 

WARC       26/        13      12     10 
KDKA        309       34      32     23 
WHAS       400       65      63     62 
WFAF      492        87     84     85 

's~' 

1 

80 

'/ 

f/ 

70 

4' 

? 

x 

W 

'/ 

60 

A' 

'/ 

// 

50 

// 

7 

/ 

A 

40 

Dial*l- 

——* 

A 

t 

/ 

<<\ 

30 

Dial*2 

w 

'Dial#3 

/ 

20 

i. 

w 

i< 

Figure  */ 
Typical  Curves 

For 
Tuned  Radio  Fre.n. 

H 

H 

— 1 
i 

10 

A 

f/ 

// 

n 

'/ 

DialSettings 

By  Bertram 

C.  Rogers, 

Engineer 

for 

the 

Westinghouse 

Electric 

at 
KDKA 


L_ 


200    240   280     320     360    400     440 


520     560 


No  Need  to  "Comb  the  Air"- 


TUNING  with  CHART  CURVES 


THE  radio  set  owner  does  not  need  to 
comb  the  air  aimlessly  to  bring  in 
any  desired  station,  if  he  will  take 
the  trouble  to  make  a  simple  chart  show- 
ing curves  of  his  dial  settings  at  various 
wavelengths. 

To  obtain  the  best  results  from  a  radio 
receiver,  it  is  neces- 
sary that  the  operator 
know  how  to  tune  it 
accurately  and  quickly. 
There  are  so  many  dif- 
ferent types  of  radio 
receivers  now  on  the 
market  that  it  will  be 
necessary  to  describe 
the  manipulation  of 
several  of  them,  but  no 
attempt  will  be  made 
to  include  all  of  them, 
nor  any  of  the  ones 
having  trick  circuits. 

The  first  set  of  which 
we  shall  speak  is  the 
"Tuned  Radio  Fre- 
quency." This  ordi- 
narily has  five  controls, 
three  for  selection  of 
stations  and  two  for 
filament  current  to  the 
vacuum  tubes.  The 
detector  is  usually  con- 
trolled by  a  separate 
rheostat  as  an  addi- 
tional aid  to  tuning. 
The  second  rheostat 
controls  all  four  ampli- 
fier tubes. 

Making 
Adjustments 

IF  your  set  has  a  fila- 
ment voltmeter, 
adjust  the  filament  cur- 
rent   until    the    meter 


reads  the  proper  value.  Otherwise 
adjust  the  rheostat  or  battery  setting 
controls  to  the  proper  position.  They 
should  be  adjusted  until  the  filament  of 
the  tubes  glow  at  the  proper  color,  and 
then  should  be  left  alone  unless  the 
battery   is   so   nearly   discharged    that   it 


TTTTTTTTT 


will  not  maintain  a  constant  glow  of  the 
tube  filaments.  If  more  than  one  re- 
setting of  the  filament  rheostat  is  neces- 
sary, it  is  advisable  to  replace  the 
battery.  It  is  then  necessary  to  tune  all 
three  "Station  Selectors"  so  that  they 
will  respond  to  the  same  waves. 

The  setting  of  all 
three  dials  is  usually 
the  same,  except  that 
one  control  may  differ 
slightly  from  the  other 
two.  If  you  do  not 
know  the  proper  set- 
tings, adjust  the  second 
and  third  so  that  the 
dials  read  the  same  and 
then  adjust  the  first 
dial  so  that  some  sort 
of  sounds  are  heard.  In 
general  the  setting  of 
the  first  dial  will  be 
approximately  the 
same  as  the  setting  of 
the  other  two  dials,  but 
may  be  slightly  above 
or  below  the  other  two. 
When  the  dials  are  at 
the  proper  setting, 
atmospheric  noises 
which  are  commonly 
known  as  static  will  be 
heard  and  possibly  also 
signals  from  a  broad- 
casting station.  In 
case  you  do  not  succeed 
at  the  first  trial,  go 
through  the  same  pro- 
cess again  starting  at  a 
slightly  different  set- 
ting. Record  the  set- 
tings of  all  three  dials 
for  three  or  more  sta- 
tions of  different  wave- 
(Turn  to  page  62) 


22 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


Graceful  Beauty  and  Tonal  Clarity 


r~T~lHE     DeForest     Radio    booth    at 
_Z     the  shows   held  in    Chicago   and 

New  York  represented  a  Spanish  bun- 
galow, in  which  was  placed  the  new 
DeForest  W-6  Renaissance  Radio- 
phone, a  typical  example  of  "har- 
monizing" receivers.  The  set  was 
placed  against  a  chrome  stucco  wall, 
with  ornate  iron  grill  work. 


ONE  of  the  most  attractive  sets 
recently  produced  by  radio 
manufacturers  is  theErla  console, 
shown  above.  It  is  the  product  of 
theElectrical  Research-Laboratories 
of  Chicago,  andis  of  the  tuned  radio 
frequency  type,  five  lubes,  with  ex-~ 
ccedingly  s i mple  and  attractive  con- 
trols. 


'  I  1HE  receivers  depicted  on  this  and  the  opposite  page 
A.  represent  the  latest  trend  in  radio  design;  namely,  for 
enhanced  grace  of  beautiful  design,  and  for  the  greatest 
possible  clarity  of  tone  and  simple  operation.  Mechanical 
development  seems  to  have  stood  still  while  the  artistic  side 
of  radio  goes  forward  by  astounding  leaps  and  bounds. 
No  expense  has  been  spared  by  some  manufacturers  to 
attain  the  greatest  beauty,  to  harmonize  with  the  most 
elaborate  surroundings;  others  have  achieved  beauty,  com- 
bined with  simplicity,  and  yet  keep  their  products  in  the 
low-priced  group.  These  receivers  were  among  those  on 
display  at  the  Fourth  Annual  Chicago  Radio  Show,  held 
at  the  Coliseum  from  November  18  to  23. 


TT^RESHMAN  Masterpiece  Receiver,  with 
JF  a  separate  battery  case  console,  one  of 
the  latest  developments  of  Chas.  Freshman, 
Inc.  The  loud  speaker  is  built-in,  and  the 
panel  especially  grained  and  engraved.  The 
receiver  may  be  had  with  or  without  the  cabi- 
net for  batteries,  although  the  latter  innovation 
greatly  adds  to  the  set's  appearance. 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour  23 


Predominate   in   Sets   at   Chicago   Show 


"^":%%.yM 


GETTING  into  the  higher  priced  class 
of  receivers,  we  discover  stick  elabor- 
ate models  as  this  Spanish  Model  made 
especially  by  the  Zenith  Radio  Corpora- 
tion and,  embodying  the  Zenith  circuit. 
The  price  of  this  set,  which,  by  the  way, 
■is  enclosed  in  this  exquisite  piece  of 
furniture,  is  $2,000. 


J1HE  regular  upright  model  Freshman 
Masterpiece  Receiver,  with  extra  large 
built-in  loud  speaker.  Otherwise  this 
model  is  identical  to  the  Freshman  re- 
ceiver pictured  on  the  opposite  page.  The 
circuit  is  of  the  popular  tuned  radio 
frequency  type,  and  the  finish  gives  the 
appearance  of  finished  mahogany  furni- 
ture. 


TfJTF.  improved  model  Laboratory  Type  Silver-Super-heiero- 
dyne,  a  development  of  McMurdo  Silver.  The  set  claims 
great  selectivity,  and  uses  the  new  Silver- Alar  shall  S-L-F 
condensers  and  interchangeable  coils.  This  super  is  on  dis- 
play at  the  Fourth  Chicago  Show,  with  other  Silver-Marshall 
parts. 


Z1RR  new  model  Ultradyne  re- 
ceiver, a  development  of  Robert 
E.  Lacault  of  the  Phenix  Radio 
Corporation.  The  feature  of  this 
receiver,  a  six  tube  T.  R.  F.  type,  is 
its  "No  Dial"  arrangement.  Tun- 
ing is  accomplished  by  small  lever 
adjustments  which  follow  a  tuning 
scale  marked  on  the  outside  of  the 
built-in  loudspeaker.  There  is  only 
one  other  adjustment — the  "on-off" 
switch.  Simple,  isn't  it?  And  the 
appearance  blends  with  home  sur- 
roundings anywhere. 


24 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


Just  What 
Constitutes  a 

GOOD  VARIABLE 

CONDENSER? 


Variety  of  Claims 
Apt  to  Confuse 
the  Listener 


WHEN  we  speak  of  the  condenser 
in  a  radio  receiving  set,  some 
people  will  think  immediately  of 
the  variable  air  condenser  which  is 
used  for  tuning  in  the  desired  station  or 
some  other  one  that  happens  to  come 
in,"  said  E.  L.  Hall  of  the  U.  S.  Bureau 
of  Standards  at  Washington.  "Other 
people  will  think  also  of  the  fixed  con- 
densers which  serve  important  functions 
in  a  radio  receiving  set.  Fixed  condens- 
ers are  used  in  some  radio  receiving 
sets  in  the  tuning  circuit  to  extend  the 
frequency  range  of  the  set." 

In  general,  fixed  condensers  are  found 
chiefly  in  the  grid  lead  of  the  detector 
tube,  and  as  a  bypass  for  radio  frequency 
currents  across  a  path  of  high  impedance 
such  as  the  primary  winding  of  an  audio- 
frequency transformer  or  the  windings 
of  a  telephone  receiver. 

There  are  a  very  large  number  of 
manufacturers  of  variable  air  condens- 
ers at  the  present  time  and  when  de- 
siring to  construct  a  radio  receiving 
set,  one  wonders  which  condenser  to 
buy.  A  perusal  of  the  advertising  of  the 
different  manufacturers  leaves  the  lay- 
man as  undecided  as  ever,  being  over- 
whelmed by  such  terms  as  low  loss,  low 
minimum,  grounded  rotor,  straight-line, 
square  law,  non-dielectric,  etc.  The 
result  is  that  he  buys  a  condenser  re- 
commended by  the  salesman,  which  may 
or  may  not  be  satisfactory. 

Now  what  constitutes  a  variable  air 
condenser  wriich  will  give  satisfactory 
operation  in  a  radio  receiving  set?  A 
few  years  ago  the  list  of  manufacturers 
of  good  condensers  would  have  included 


a  very  few  names  because  there  were 
very  few  manufacturers  of  such  appara- 
tus at  that  time.  Today  such  a  list 
would  be  very  long  indeed  so  that  instead 
of  mentioning  the  names  of  the  makers 
of  the  best  condensers,  the  essential 
points  to  look  for  in  the  best  condensers 
will  be  given. 

Construction  of  Condenser 

T3EF0RE  giving  these  points  let  us 
-•— '  consider  the  construction  of  a 
variable  air  condenser.  It  consists  es- 
sentially of  two  sets  of  parallel  metal 
plates,  one  set  being  rigidly  fastened  to  a 
mounting  while  the  other  set  is  fastened 
to  a  shaft  enabling  these  plates  to  rotate 
between  the  fixed  plates.  The  two  sets 
of  plates  are  electrically  insulated  from 
each  other. 

For  this  purpose  different  manufac- 
turers use  different  materials  and  methods 
for  obtaining  this  result.  Materials 
used  for  insulation  include  bakelite, 
glass,  hard  rubber,  isolantite,  porcelain 
and  quartz.  The  electrical  requirements 
for  the  best  condenser  if  met  are  such  as 
to  produce  a  very  poor  condenser 
mechanically,  so  that  a  compromise  is 
necessary. 

However,  a  satisfactory  condenser  will 
have  no  lateral  or  longitudinal  motion 
of  the  shaft;  will  turn  freely  and  posi- 
tively; will  have  the  plates  made  of  mater- 
ial of  sufficient  thickness  to  maintain  its 
calibration;  will  not  have  stops  to  pre- 
vent the  complete  rotation  of  the 
movable  plates  and  the  possible  jarring 
of  plates  out  of  line  or  displacement  of 
the  dial;  will  employ  a  minimum  amount 


E.  L.  Hall, 
Government 
Radio  Expert, 
Gives  His  Opinion 
of  Ideal  Condenser 


of  insulating  material  consistent  with 
strong  mechanical  design  and  have  it 
placed  well  away  from  the  plates  of  the 
condenser;  will  have  sufficient  spacing 
between  plates  to  guard  against  shorting 
the  two  sets  of  plates;  will  have  a  neat 
and   pleasing   appearance. 

It  will  be  noticed  that  these  require- 
ments are  chiefly  of  a  mechanical  nature. 
None  of  the  advertising  terms  have  been 
mentioned  because  the  advantages  claim- 
ed for  some  types  of  condensers  are 
questionable. 

One  illustration  will  suffice.  Manufac- 
turers have  vied  with  one  another  to 
produce  a  variable  condenser  having  the 
lowest  minimum  capacity.  Condensers 
used  near  the  low  part  of  the  capacity 
scale  have  relatively  large  changes  in 
total  capacity  of  the  circuit  for  a  slight 
movement  of  the  dial,  which  means  that 
it  is  extremely  difficult  to  tune  in  a 
station  on  this  part  of  the  dial. 

Operator's  Hand   May  Affect  It 

TN  SOME  sets  it  may  be  found  that 
-*-  the  presence  of  the  operator's  hand  or 
body  will  tune  or  detune  the  receiving 
set.  In  such  sets  this  will  be  extremely 
marked  for  low  settings  of  the  dial  of 
the  condenser.  The  resistance  of  the 
condenser  is  also  quite  high  for  low  set- 
tings of  the  dial,  which  is  a  disadvantage. 
The  whole  question  as  to  the  con- 
denser may  be  summed  up  by  saying 
that  dependable  results  may  be  expect- 
ed in  a  receiving  set  employing  a  variable 
air  condenser  made  by  a  reputable  firm, 
where  due  regard  for  mechanical  design 
has  been  taken. 


RADIO  AGE  for  December,  1925 


77. e  Magazine  of  the  Hour  25 


BACK  FROM  the  ARCTIC 


Radio  group  on 
maiden  voyage 
of  the  Peary. 
Left  to  right, 
PaulB.  Klugh, 
Eastern  Mana- 
ger Zenith  Ra- 
dio Corp. .Com- 
mander E.  F. 
McDonald,  Jr., 
President  Zen- 
ithRadio  Corp., 
Commande  r 
DonaldB. 
MacMillan,  fa- 
mous Arctic  ex- 
plorer, Douglas 
Rigney,  Mana- 
ger A.  H.  Grebe 
&  Co.  and  C. 
H.  Thordarson, 
PresidentThor- 
darson  Electric 
and    Mfg.    Co. 


National  Qeographic  Society  and  U.  S.  Navy, 
Sponsors  of  the  Adventuresome  Summer  Voyage 
are  Qiven  Accurate  Records  of  the  Eventful  Trip 


PRESIDENT  E.  F.  McDonald,  Jr., 
of  the  Zenith  Radio  Corporation,  re- 
turned to  Chicago  on  October  23 
after  an  adventurous  summer  in  the  arc- 
tics, where  he  was  second  in  command  of 
the  MacMillan  Arctic  Expedition.  Mr. 
McDonald  was  in  command  of  the 
"Peary,"  the  larger  of  the  two  vessels 
that  carried  the  explorers  to  their  base, 
less  than  12  degrees  from  the  north  pole. 

Perils  of  Journey 

Several  volumes  could  be  written 
about  the  perils  of  the  journeys  to  the 
polar  region  and  back  again.  Com- 
mander McDonald's  brief  reports  on  a 
few  incidents  of  the  expedition  are  sug- 
gestive of  tales  of  Sinbad  the  Sailor, 
with  the  difference  that  Commander 
McDonald's  experiences  really  happened 
and  those  of  the  gentleman  mentioned 
were  pure  fiction. 

Happily  the  facts  about  the  MacMillan 
expedition  are  in  the  accurate  records  of 
the  National  Geogra  hie  Society  and  the 
United  States  Navy  Department,  both 
of  which  organizations  sponsored  the 
expedition  and  gave  it  their  active  co- 
operation. 

Radio    Research 

From  a  radio  point  of  view,  the  main 
interest  in  Commander  McDonald's 
experiences   naturally  centers   about   his 


radio  researches  and  demonstrations 
while  up  there  in  the  land  of  the  mid- 
night sun,  amid  electrical  disturbances 
and  phenomena  which  are  not  encoun- 
tered in  the  temperate  zones. 

One  great  achievement  of  Commander 
McDonald  and  his  staff  was  the  solving 
of  the  problem  of  daylight  transmission 
by  radio.  As  head  of  the  Zenith  Corpora- 
tion Commander  McDonald  naturally 
was  deeply  interested  in  the  wireless 
knowledge  to  be  obtained  from  experi- 
ments in  a  region  where  for  months  at  a 
stretch  there  is  continuous  sunlight. 

Heavy   Message   Traffic 

Low  wave  transmission  was  the  special 
object  of  Commander  McDonald's  inter- 
est and  he  gave  this  phase  of  wireless 
communication  a  most  exhaustive  and 
successful  test.  Through  the  intelligent 
and  industrious  efforts  of  Chief  Operator 
Paul  J.  McGee,  also  a  Chicagoan,  the 
"Peary"  was  able  to  dispatch  more  than 
one  and  one  half  millions  of  words  while 
the  ship  was  in  the  north  country. 

Not  in  the  volume  of  correspondence 
alone  but  in  the  vast  distances  regularly 
reached  by  the  "Peary's"  forty-meter 
transmitter  did  the  achievements  of  the 
expedition  attract  the  attention  and 
gain  the  applause  of  the  radio  world. 
Regular  communication  was  maintained 
in  daylight  with  New  Zealand  and  Aus- 


tralian stations.  Intermediate  points 
almost  without  number,  were  almost 
continuously  talking  back  and  forth 
with  the  explorers. 

The  Arctic  expedition  demonstrated 
the  fact  that  the  low  wave  could  pene- 
trate great  distances  and  established  the 
ease  with  which  regular  daylight  com- 
munication  could   be   maintained. 

Ultra-short  waves 

As  greater  research  is  made  on  the 
subject  of  the  ultra-short  waves  covering 
the  zone  between  5  and  50  meters,  it 
seems  their  performance  becomes  more 
freakish  than  the  uniform  and  fairly 
regular  antics  of  the  higher  waves 
between  100  and  200  meters.  Much  of 
the  success  and  ease  of  the  transmission 
between  the  Pclar  regions  and  the  anti- 
podes can  probably  be  traced  to  the  fact 
extremely  short  waves  are  great  for  long 
distance  transmission  whereas  they  are 
not  quite  so  successful  for  what  might 
be  termed  local  work.  It  is  not  unrea- 
sonable to  expect  in  the  near  future  the 
distance  to  be  covered  will  determine 
largely  the  wavelength  to  be  used.  For 
essentially  local  work  the  200  meter  band 
might  be  o.  k.,  whereas  if  it  is  desired  to 
plunk  a  signal  into  the  ears  of  a  listener 
thousands  of  miles  away  the  short  band 
from  5  to  20  and  perhaps  up  to  50  meters 
will  be  utilized. 


26  RADIO  AGE  for  December,  1925  The  Magazine  of  the  Hour 


Another  Model 


Having  presented  our  readers  with  the  December  Radio  Age  Model  H 
receiver  in  this  issue  of  our  magazine,  we  are  now  going  ahead  with  the 
Model  HX  which  is  scheduled  for  the  January  number. 

Many  refinements  and  improvements  will  be  added  to  the  January 
Model.  Other  inductances,  capacities  and  allied  units  will  make  up  the 
January  feature  so  the  reader  inclined  towards  the  building  of  sets  will 
have  an  excellent  opportunity  of  observing  the  manner  in  which  full 
advantage  is  taken  of  all  types  of  radio  apparatus  in  the  series  of  articles 
now  well  under  way. 

A  Workable  Set 

All  of  the  bugs  and  grief  which  the  ordinary  experimenter  encounters  in 
the  construction  of  a  set  has  been  taken  out  by  the  Technical  Staff  of 
Radio  Age  and  as  a  consequence  you  can  go  ahead  with  the  building  with- 
out having  to  scratch  your  head  and  puzzle  over  some  of  the  little  details. 
We  believe  this  practice  of  sidetracking  your  troubles  before  they  reach 
you  will  prove  one  of  the  most  popular  features  ever  presented  in  the 
pages  of  Radio  Age. 

Several  Surprises 

We  are  withholding  the  intimate  details  of  the  receiver  because  we  have 
a  few  surprises  in  store  for  you — something  which  we  believe  will  still 
further  convince  you  of  the  fact  Radio  Age  leads  in  the  radio  magazine 
field.  Keep  your  eyes  on  the  news-stands;  the  January  number  will  be 
out  about  December  15. 

RADIO  AGE,  Inc. 

510  N.  Dearborn  Street  -:-  -:-  Chicago,  Illinois 


RADIO  AGE  for  December,  1925 


What  the  Broadcasters  are,  Doing  27 


A  Case  of  "Microphone  Fright" 


STAGE  fright  may  have  its  terrors,  but  for  that  real,  helpless  feeling,  a  first  appearance 
before  a  stern  microphone  is  recommended.  Above  is  Patsy  Ruth  Miller,  Warner 
Brothers  movie  star,  at  the  Microphone  of  Staton  KWBR,  endeavoring  to  broadcast  for 
the  first  time.  Louise  Fazenda,  an  old-timer  at  the  gentle  art  of  broadcasting,  is  offering 
moral  support,  with  doubtful  success. 


28  RADIO  AGE  for  December,  1925 


Wkat  tke 
Broadcasters  i 
are  Doing 


The  Magazine  of  the  Hour 

I 


South  to  Get  a  New 
Station 

November  1st  saw  the  advent  of  one 
of  the  largest  radio  broadcasting  stations 
in  the  south,  erected  at  Boca  Raton,  by 
the  Mizner  Development  Corporation. 
The  announcement  of  the  huge  station 
that  was  installed  by  the  Western 
Electric  Company  from  designs  of  the  Bell 
Telephone  laboratories,  comes  with  great 
interest  for  the  radio  fans  all  over  the 
country. 

The  station  is  being  built  under  the 
supervision  of  George  Sheffield,  of  New 
York.  The  call  letters  of  the  new  station 
will  be  WFLA. 

The  two  great  towers  that  rear  them- 
selves to  the  height  of  two  hundred  feet 
will  become  familiar  landmarks  to  travelers 
through  Boca  Raton.  The  studio  of  the 
station  that  snuggles  near  the  towers 
was  designed  by  Addison  Mizner,  follow- 
ing the  architectural  precedent  set  in 
Boca  Raton  of  the  langourous  Spanish 
style,  also  the  barracks  that  house  the 
members  of  the  Yerkes  Flotilla  Orchestra, 
one  of  the  principal  performers  engaged 
for  the  winter  season. 

Technically,  the  station  is  one  of  the 
finest  that  has  ever  been  installed.  The 
rated  power  output  of  the  station  is  1000 
watts,  but  ample  tube  capacity  is 
provided  for  the  peak  value  reached 
<luring  modulation.  This  is  ordinarily 
about  2500  watts.  The  equipment 
consists  of  the  radio  transmitter  with  the 
necessary  speech  input  apparatus.  The 
transmitter  is  complete  in  one  unit. 

To  the  radio  engineer  the  station  at 
Boca  Raton  presents  a  dream  of  perfec- 
tion. The  entire  station  is  the  last  word 
in  effective  radio  design,  and  the  maxi- 
mum utility  from  the  station  is  guaranteed 
at  all  times.  The  power  apparatus,  the 
motor  generators  and  starting  equipment 
is  located  in  a  separate  room  from  the 
transmitter  but  is  controlled  from  the 
front  panel  of  the  transmitter.  Two 
motor  generators  provide  the  supply. 
One  set  consists  of  a  24  volt  generator  to 
provide  the  filament  current;  a  250  volt 
story  generator  for  the  grid  voltage 
supply  and  the  excitation  of  the  high 
voltage  machine;  and  a  four  horsepower 
mounted  in  the  same  base  with  the  two 
generators.  The  other  set  consists  of  two 
2000  volt  generators  and  an  eight  horse- 
power driving  motor. 

The  two  machines  are  controlled  by 
automatic  starters. 

The  entire  station  will  be  active  all 
winter  long.  Programs  featuring  the 
foremost  luminaries  of  the  opera  stage 
and  concert  stage  as  well  as  jazz  concerts 
and  dance  music  will  be  broadcast. 
Through  a  special  microphone  that  may 
be  carried  around  from  place  to  place, 
outstanding  events  and  concerts  from 
Palm  Beach  and  the  other  nearby  towns 
may  be  broadcast. 


Logan  ("Steve")  Trumbull,  formerly  Chief 
announcer  of  KYW,  who  is  unable  to  resist  the  lure 
of  the  open  road,  and  is  going  West,  so  we  under- 
stand. After  he  has  finished  visiting  the  South. 
Steve  is  an  old  newspaperman;  writes  plays  and 
they  are  really  produced;  and  does  many  other 
things,  but  he  hans't  been  afcle  to  vanguish  the 
the  wanderlust.  Good  luck,  Steve — they'll  miss 
you  on  the  air. 

Air  Channel  Proves 
Valuable 

Within  a  short  time  there  nay  be  a 
new  commodiy  on  the  market — broad- 
cast wave  lengths.  The  possession  of  a 
good  broadcasting  channel,  of  say  400 
meters,  is  worth  far  more  today  than 
400  shares  of  any  radio  stock.  It  is 
probably  worth  four  times  that  amount 
due  to  the  scarcity  of  broadcast  channels 
suitable  for  Class  B  stations.  A  good 
broadcasting  station  or  a  "seat  on  the 
air"  may  be  worth  just  as  much  as  a  seat 
on  the  stock  exchange. 

At  any  rate,  it  is  reported  that  Charles 
E.  Erbstein  of  Elgin,  Illinois,  has  sold 
his  two  stations  to  the  Liberty  Magazine 
for  $250,000.  The  value  of  these  stations 
was  perhaps  $50,000  each;  they  could 
certainly  be  duplicated  for  half  the 
amount  paid  for  their  possession.  But 
their  ownership  without  a  broadcasting 
wave  channel  would  be  valueless,  and 
wave   lengths  are  exhausted. 

This  leads  to  the  estimated  value  of 
some  wave  lengths  at  about  §75.00  each, 
dependent  upon  certain  factors,  location 
for  example.  Evidently  the  Liberty 
Magazine  wanted  to  go  on  the  air  and 
as  their  were  no  available  channels  for 
broadcasting,  this  company  bought  two 
stations,  wave  lengths  included.  This 
transaction  is  altogether  proper  as  far 
as  can  be  determined.  The  Department 
of  Commerce  is  understood  to  be  disposed 
to  O.  K.  the  transfer  of  ownership,  pro- 
vided the  station  is  not  moved.  The 
Government  will  probably  renew  the 
broadcasting  license  when  it  is  expired 
in  the  name  of  the  new  owner.  But  the 
station  with  its  wave  channel  could  not 
be  removed  to  another  city  due  to 
allocations. 


Another  New  Zealander  Tunes 
In  on  WBBM 

New  Zealand,  approximately  one-third 
of  the  way  around  the  world,  is  now 
tuning  in  on  Chicago  regularly,  according 
to  a  letter  received  by  Ralph  Atlass, 
co-director  of  Station  WBBM  at  Chicago 

The  letter,  from  Spencer  Speedy, 
Pipi  banks,  Herbertville,  Hawks  Bay 
New  Zealand,  states  the  writer  had  been 
receiving  WBBM  regularly  "the  last 
few  weeks"  prior  to  Sept.  21. 


Wireless  Matters  May  Be  De- 
layed Until  Next  Fall 

Echoes  from  the  Paris  Telegraph 
Conference,  drawing  to  a  close,  indicate 
that  the  American  Radio  Telegraph 
Conference  scheduled  to  be  heTd  in 
Washington  next  spring,  will  probably  be 
postponed  until  late  next  fall. 

Although  invitations  have  been  sent  to 
over  forty  foreign  nations  asking  them  to 
participate  in  the  world-wide  wireless 
sessions,  and  the  appropriations  made 
by  Congress  provide  that  the  monies 
must  be  used  prior  to  June  30,  1926,  it  is 
believed  by  "those  in  the  know,"  that  a 
postponement  will  be  found  necessary  or 
at  least  advantageous. 

One  of  the  chief  reasons  for  believing 
that  a  delay  would  be  desirable  is  because 
the  Paris  Telegraph  delegates  are  re- 
reported  as  unanimous  in  the  belief  that 
a  combination  of  the  telegraph  and  the 
radio  telegraph  conventions  is  desirable. 
Another  is  because  certain  committees 
have  been  created  and  directed  to  work 
out  some  of  the  world's  communication 
problems,  reporting  by  October  31,  1926, 
to  the  first  international  conference.  It 
would  appear  advantageous  to  have  these 
matters  discussed  at  Washington  rather 
than  to  have  them  lie  unadopted  possibly 
for  several  years  awaiting  the  next 
general  conference. 

Nothing  was  done  in  Paris  to  interfere 
with  the  scope  of  the  forthcoming  radio 
parley  at  Washington;  that  is,  nothing 
pertaining  to  radio  of  a  technical  nature 
was  injected  into  the  wire  conference.  So 
questions  relating  to  wireless  communica- 
tion including  broadcasts  and  amateur 
work  will  remain  open  for  discussion  when 
the  Washington  conference  is  held. 

Upon  the  recommendations  of  the 
delegates  of  Great  Britain,  France, 
Germany,  Italy,  China  and  some  other 
countries,  the  Paris  conference  went  on 
record  as  favoring  a  combination  of  the 
two  world  communication  conventions 
into  one  to  cover  electrical  communica- 
tions sent  by  wire,  cable  or  via  radio, 
which  will  probably  be  effected  at  the 
next  conference. 

Recent  reports  from  Paris  state  that  a 
sub-committee  on  rates  and  codes  passed 
a  resolution  creating  a  special  committee 
composed  of  delegates  from  Great 
Britain,  Germany,  Greece,  France,  Bel- 
gium, Turkey,  Russia,  the  Dutch  East 
Indies  and  Italy,  to  study  the  code 
systems  with  regard  to  the  adoption  of  a 
new  universal  five-character  code.  This 
committee,  if  appointed,  and  it  is  be- 
lieved the  Conference  will  agree  to  do  so, 
would  also  fix  new  tariffs  in  accord  with 
those  of  the  present  codes  approved  by  the 
Conference.  It  would  naturally  report  to 
the  first  international  conference  held, 
probably  the  Washington  Radio  Con- 
ference, as  there  is  not  likely  to  be  another 
Telegraph  Conference  for  several  years. 


RADIO  AGE  for  December,  1925 


What-the  Broadcasters  Are  Doin° 


29 


E.  Warren  K.  Howe  New 

Musical  Director  WJAZ 

The  Zenith  Radio  Corporation  an- 
nounces it  has  obtained  the  services  of 
Mr.  E.  Warren  K.  Howe  as  Musical 
Director  of  station   "WJAZ." 

That  Mr.  Howe's  influence  cannot 
help  but  be  a  tremendous  factor  in  giving 
to  the  public  only  the  highest  type  of 
musical  program  is  indicated  by  his 
training  from  childhood  in  the  musical 
field.  Through  the  influence  of  a  genuine 
artistic  environment  in  his  youth,  Mr. 
Howe  enjoyed  unusual  advantages  for 
a  healthy  development  of  his  decided 
musical  gifts.  In  his  early  days,  he  was 
a  student  of  violin  and  piano  and  boy 
soloist  in  the  Church  of  the  Ascension, 
Chicago. 
-  After  three  years  of  orchestral  experi- 
ence as  violinist,  he  took  up  the  study 
of  voice,  undergoing  a  thorough  course 
of  training  with  one  of  America's  noted 
teachers;  then  entered  upon  a  stage 
career  under  the  management  of  Abbey, 
Schoeffel  and  Grau.  After  this,  he  was 
a  member  of  the  Schiller  Opera  Com- 
pany in  repertoire  light  opera,  thus  gain- 
ing valuable  stage  experience. 

After  five  years'  experience  as  singer 
and  teacher  of  voice,  Mr.  Howe  went 
to  Paris,  further  perfecting  himself  under 
the  guidance  of  Jacques  Bouhy,  the 
eminent  master  of  the  voice.  Through 
the  influence  of  Bouhy,  he  established 
himself  in  Paris  as  a  teacher  of  singing 
and  as  bass  soloist  of  Trinity  Church, 
Avenue  de  l'Alma.  He  was  also  Paris 
correspondent   for   the    Musical    Leader. 

Returning  to  America,  Mr.  Howe 
entered  actively  into  musical  work  as 
pedagogue,  in  concert  and  oratorio  sing- 
ing, and  subsequently  as  conductor  of 
light  opera  and  oratorio.  He  has  had  at 
various  times  under  his  baton  in  con- 
junction with  musical  festivals  the 
country's  best  artists  and  the  New  York 
Symphony  Orchestra,  the  Chicago  Sym- 
phony Orchestra,  the  St.  Louis  Sym- 
phony Orchestra  and  the  Minneapolis 
Symphony  Orchestra  seven  times.  He 
has  also  been  at  the  head  of  the  vocal 
department  of  one  of  America's  foremost 
conservatories  for  several  years. 


Goodrich  and  KFNF  to 
Liberate  Balloons 

Three  hundred  sounding  balloons  rang- 
ing in  sizes  from  two  to  three  feet  in 
diameter  and  inflated  with  hydrogen 
gas  are  soon  to  be  liberated  from  Shenan- 
doah, Iowa.  This  will  be  the  beginning 
of  an  experiment  being  arranged  by  The 
B.  F.  Goodrich  Rubber  Company  in 
cooperation  with  the  Henry  Field  Seed 
Company's   radio   station    KFNF. 

The  purpose  of  the  experiment  is  two- 
fold. First  to  study  the  directional 
features  of  different  atmospheric  levels 
for  aeronautical  information  and  second 
to  study  those  currents  with  respect  to 
their  possible  influence  upon  radio  broad- 
cast   reception. 

The  Goodrich  Company's  interest 
applies  to  both  fields.  They  were  the 
first  rubber  company  to  accept  radio  as 
a  medium  for  presenting  good-will  enter- 
tainment to  millions  of  radio  listeners 
and  they  manufacture  many  hard  rubber 
radio  accessories.  On  the  other  hand  they 
are  extensively  interested  in  aeronautics, 
being  manufacturers  of  many  accessories 
for  both  lighter-than-air  and  heavier- 
than-air    crafts. 

The  balloons  to  be  used  in  this  experi- 
ment are  of  the  type  government  metero- 


logical  experts  use  in  taking  altitude 
tests  of  atmospheric  conditions.  They 
will  be  inflated  at  varying  pressures  pre- 
determined to  gauge  the  altitude  at 
which  the  balloon  will  travel. 

Tags  attached  to  the  balloons  have 
specific  instructions.  These  instructions 
together  with  the  announcements  that 
will  daily  be  broadcast  from  KFNF  are 
expected  to  get  full  cooperation  of  those 
who  find  the  balloons  in  reporting  loca- 
tion   and    time. 


Miss  Irma  Carpenter,  soprano,  who  appears  in 
role  of  soloist  on  the  Teaberry  Time  programs, 
broadcast  from  Station  KDKA  at  Pittsburgh. 


Hurrah!  We'll  All  Angle  for 
DXNow 

Broadcasters  of  the  United  States  will 
gladly  stay  off  the  air  one  hour  each 
evening  during  International  Radio 
Week,  January  24-30,  1926,  according  to 
advance  information  received  by  the 
executive  committee  handling  this  event. 

Formal  action  by  the  broadcasters  of 
the  United  States  will  come  at  a  meeting 
of  the  National  Association  of  Broad- 
casters this  body  being  expected  to  handle 
the  broadcasting  features  of  the  week 
from  the  American  side. 

"While  we  have  no  official  word  from 
the  broadcasters  society,"  L.  A.  Nixon, 
secretary  of  the  radio  week  committee 
said,  "we  have  had  advance  assurance 
from  some  of  the  more  prominent  broad- 
casters of  the  country  that  there  will 
be  no  question  of  a  hitch  in  observing 
the  silent  hour  so  that  American  lis- 
teners may  hear  the  overseas  stations. 

"The  official  silent  hour  will  be  from 
eleven  to  twelve  eastern  standard  time, 
according    to    our    present    information. 

"The  change  of  date  from  late  in 
November  to  January  24-30  wnich  was 
authorized  at  the  recent  meeting  of  the 
radio  week  committee,  was  made  so  as 
to  bring  the  event  and  the  accompany- 
ing international  radio  broadcasting  tests 
into  the  best  possible  season  of  the  year, 
January  being  conceded  a  better  radio 
month  than  November,  for  overseas 
broadcasting. 


National  Exchange  of 
Radio  Recipes 

Radio  has  brought  about  a  national 
exchange  of  cooking  recipes.  When  Mrs. 
New  York  is  a  little  bit  in  doubt  about 
the  meringue  for  her  pie,  she  is  just  as 
likely  to  ask  Mrs.  California  or  Mrs. 
Minnesota  for  advice  as  she  is  her  next- 
door  neighbor.  If  young  Mrs.  Wisconsin 
can't  get  her  baked  beans  quite  as  brown 
as  "mother  used  to  bake  them,"  she  can 
call  .upon  the  famed  authority  on  the 
subject,  Mrs.  Boston.  If  a  contemplated 
Southern  dinner  is  on  the  mind  of  Mrs. 
Michigan,  she  can  get  suggestions  for  it 
from  her  friend,  Mrs.  Missouri. 

It  has  all  happened  since  Betty  Crocker 
began  broadcasting  her  Home  Service 
Talk  on  September  21st  from  twelve  of 
the  largest  broadcasting  stations  from 
Boston  to  Los  Angeles.  From  Coast  to 
Coast,  according  to  letters  received  by 
the  stations  participating,  housewives 
tune  in  on  their  favorite  broadcaster  at 
approximately  10:45  Mondays,  Wednes- 
days, and  Fridays  to  hear  what  Betty 
Crocker  has  to  say  and  to  get  the  newest 
recipes  she  offers.  Their  next  step,  as  a 
rule,  is  to  sit  down  and  write  Miss 
Crocker,  telling  her  how  the  recipe  came 
out  and  to  send  her  a  few  of  their  own 
favorites.  Then  they  write  to  their 
friends,  relatives,  and  daughters  in  other 
cities  to  tell  them  about  this  new  cooking 
school  over  the  air  and  urge  them  to 
listen  in  on  the  nearest  station  which  is 
broadcasting  the  service. 

For  instance,  a  farmer's  wife  in  northern 
Minnesota  wrote  that  she  had  been  so- 
busy  cultivating  corn,  poisoning  potato 
bugs,  helping  with  the  harvest,  and 
putting  up  approximately  a  thousand 
quarts  of  preserves,  that  she  hadn't  had 
time  to  listen  to  the  radio  all  summer, 
but  now  that  Betty  Crocker  was  on  the 
air,  she  had  had  the  radio  set  fixed  up. 

"I  get  the  talks,"  she  wrote,  "from 
WCCO,  but  I  have  a  daughter  married, 
and  living  in  an  apartment  in  New  York 
City.  She  always  liked  to  cook,  but 
don't  imagine  she  has  much  opportunity 
now.  I  am  sure,  however,  that  she  will 
like  these  radio  cooking  school  lessons, 
so  I  have  written  her  to  tune  in  on  WEAF." 

Many  of  the  Eastern  housewives  who 
wish  to  listen  to  the  Betty  Crocker 
Talks  have  the  choice  of  getting  them 
from  WEAF,  New  York,  WEEI,  Boston, 
WGR,  Buffalo,  or  WFI,  Philadelphia.  In 
the  Middle  West  Betty  Crocker's  audience 
tunes  in  on  WCAE,  Pittsburgh,  WWJ, 
Detroit,  or  WHT,  Chicago.  In  the  South 
and  Southwest,  these  various  culinary 
suggestions  go  out  from  KSD,  St.  Louis, 
and  WDAF,  Kansas  City,  Mo.  Up  in 
the  Northwest,  where  Betty  Crocker 
made  her  debut  last  year,  they  tune  in  on 
the  Gold  Medal  Station,  Saint  Paul — 
Minneapolis,  WCCO.  Although  the 
range  of  this  Station  extends  to  the 
Pacific  Coast  and  up  into  Canada,  the 
ladies  in  the  far  West  depend  upon  KFI. 


Has  Dulcetone 

One  of  the  most  unique  instruments  to 
be  heard  on  the  air,  the  dulcetone,  has 
been  added  to  the  musical  equipment  of 
the  Wrigley  building  studios  of  WHT  and 
selections  are  played  nightly  on  it  by 
Al  Carney  and  Miss  Helen  Rauh,  staff 
accompanists. 

The  dulcetone  in  effect  is  a  minature 
piano  and  has  but  44  keys.  It  is  34  inches 
long  and  can  be  held  on  the  knees  of  the 
artist  playing  it.  The  dulcetone  was 
obtained  by  WHT  in  Glasgow,  Scotland. 


30 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


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RADIO  AGE  for  December,  1925 


What  the  Broadcasters  are  Doi 


31 


B 


ATTLING  in  the 
ring      amid      the 


It's  All  In  Fun! 


cries  of  thousands 
i.nd  attempting  to  deliv- 
er a  short  address  over 
the  radio  in  the  quiet 
surroundings  of  a  broad- 
casting studio,  are  alto- 
gether different,  accord- 
ing to  Mike  McTigue, 
world's  light  heavy- 
weight champion  boxer 
who  recently  visited 
WGY,  the  General  Elec- 
tric broadcasting  station 
at  Schenectady,  N.  Y. 

Kolin  Hager,  chief  an- 
nouncer at  the  station, 
recalls  it  as  one  of  the 
outstanding  humorous 
events  of  the  three  years 
that  the  station  has  been 
in  existence. 

"He  was  scheduled  to 
deliver  a  few  words  on 
boxing,"  explained  Mr. 
Hager.  "Naturally,  he 
was  the  last  man  in  the 
world  that  we  expected 
would  suffer  a  case  of 
'microphone  fright,'  but 
he  did.  He  stepped  up 
to  the  pick-up  device, 
but  he  could  not  talk. 
'I  would  rather  face 
Dempsey  than  talk  into 
that  thing,'  he  said. 
The  result  was  that  his 
trainer,  who  accompan- 
ied him  to  the  studio, 
was  compelled  to  read 
the     written     address." 

WGY  is  about  to  cele- 
brate the  fourth  year  of 
its  existence.  Mr.  Hager  has  been  in  charge 
of  the  announcements  since  the  institution 
of  the  station. 

Wasted    Energy! 

I"  MADE  my  first  announcement  on 
-"-  the  night  of  February  21,  1922,  and 
with  many  misgivings,"  said  Hager. 
"I  had  rehearsed  just  what  I  was  going 
to  say  twenty-five  or  thirty  times,  and 
then,  when  the  time  for  the  announce- 
ment arrived,  I  said  something  alto- 
gether different  from  that  which  I  had 
intended." 

The  WGY  studio  is  a  comfortably 
furnished  suite  of  rooms  on  the  first 
floor  of  a  new  office  building.  The  room 
from  which  come  the  songs  and  selections, 
speeches,  readings,  comedies  and  dramas, 
is  furnished  with  nothing  in  the  way  of 
scenery  such  as  is  found  in  theatres. 
Yet  it  was  only  a  short  time  ago  that  the 
.studio  officials  received  a  call  from  a 
traveling  scenic  artist  who  had  been  told 
that  he  might  land  a  job  at  WGY  paint- 
ing scenery  for  the  radio.  He  was  ad- 
vised that  he  would  get  the  job  if  he  could 
arrange  a  suitable  tableau  for  the  radio. 

Wants  Hubby's  Death  Broadcast 

"One  day  the  phone  rang  rather 
vigorously,"  said  Hager,  "and  I  answered 
it  to  receive  this  message:  'My  husband 
is  dead,  thank  God,  and  I  wish  you  would 
broadcast  the  fact.'  "     Hager  said  that 


An  Impromptu  Chat 
with  Station  WGY 

By  MILTON  LIEBERMAN 


The  WGY  orchestra  has  been  heard  all  over  the  United  States,  England, 
France  and  other  European  countries,  particularly  during  the  last  few  weeks, 
when  WGY  has  been  experimenting  with  50,000  watts.  This  orchestra  has 
been  with  WG  Y  ever  since  it  first  came  on  the  air,  and  is  still  going  strong. 


it  wasn't  news — husbands  never  last 
long,   anyway. 

WGY  was  the  first  of  three  stations  to 
be  constructed  by  the  General  Electric 
Company.  The  second,  KGO,  located  at 
Oakland,  California,  opened  early  in 
1924,  and  the  third  was  put  in  operation 
at  Denver  in  the  winter  of  the  same  year. 
All  three  stations  are  operated  under  the 
management  of  Martin  P.  Rice.  The 
equipment  of  the  stations  at  Oakland  and 
Denver  resulted  from  the  experience 
gained  at  WGY,  and  the  experimenting 
of  G-E  engineers  at  Schenectady.  WGY 
has  been  a  laboratory  for  transmission 
development. 

While  the  radio  engineers  have  always 
sought  first  for  quality,  they  take  pride 
in  the  fact  that  WGY  on  a  single  evening 
— it  was  December  24,  1923 — was  heard 
and  reported  from  every  state  in  the 
Union  as  well  as  from  Hawaii,  South 
America,  Canada  and  England.  The 
station's  record  is  Johannesburg,  South 
Africa,  a  distance  of  7890  miles.  This 
reception  was  reported  by  N.  Grant 
Dalton,  an  amateur,  on   May  22,   1924. 

In  connection  with  the  development  of 
broadcasting  equipment  and  the  im- 
provement of  transmission  quality  at 
WGY,  General  Electric  engineers  have 
developed  a  magnetic  piano  microphone. 
By  its  use  music  is  received  through 
loud  speakers  with  improved  quality. 
Extensive  experiments  have  been    made 


with  short  waves  from  107 
meters  to  15  meters.  To 
facilitate  broadcasting  of 
programs  originating 
outside  of  the  studio, 
such  as  concerts  in  pub- 
lic halls,  productions  in 
theatres,  church  serv- 
ices, etc.,  WGY  has  de- 
veloped a  portable  trans- 
mitting apparatus  by 
means  of  which  the 
customary  land  wire  link- 
between  the  scene  of  the 
concert  and  the  trans- 
mitting apparatus  is  sup- 
planted by  a  radio  link. 
The  portable  station, 
of  comparatively  low 
power,  picks  up  the  sig- 
nal and  relays  on  100 
meters  wavelength  to 
WGY,  where  it  is  put  on 
the  air  with  greater 
power  and  on  380  met- 
ers. 


Cop   Wants  to  Arrest 
Speaker 

T7"0LIN  HAGER,  af- 
-*-^-  ter  the  first  year  of 
broadcasting,  concluded 
that  the  radio  audience 
would  soon  tire  of  a 
repetition  of  programs 
made  up  of  solo  num- 
bers, even  tho  given  oy 
artists  of  international 
reputation.  To  provide 
novelty  and  entertain- 
ment he  has  included 
in  WGY  program  sev- 
eral features  which  in- 
variably bring  a  flood  of 
complimentary  letters.  For  example,  WGY 
periodically  puts  on  a  farmer's  night 
program.  On  one  occasion  it  was  Josh 
Quinby's  golden  wedding  anniversary; 
on  another  Josh  had  a  husking  bee. 
The  minstrel  show  has  also  been  a  popu- 
lar feature  of  the  station,  and  recently 
a  burlesque  on  the  national  conventions 
was  produced  so  successfully  that  a 
"return  engagement"  was  booked.  WGY 
has  a  light  opera  company  which  has 
produced  three  of  four  of  the  Gilbert  and 
Sullivan  rollicking  operas. 

In  August,  1922,  Edward  H.  Smith 
and  a  small  group  of  players,  all  of  pro- 
fessional experience,  were  engaged  to 
produce  Eugene  Walter's  play,  "The 
Wolf."  It  was  the  first  experiment 
with  the  radio  drama.  The  play  made 
an  instantaneous  hit.  Letters  were 
received  from  all  parts  of  the  country 
and  from  people  in  all  walks  of  life, 
urging  a  continuance  of  radio  dramas. 
A  Pittsfield,  Mass.,  policeman,  hearing 
cries  for  help  coming  from  a  modest 
bungalow,  demanded  admission  and  the 
cause  for  the  shouts.  He  was  shown  the 
loud-speaker  from  which  were  issuing 
the  cries  of  a  heroine  in  the  grip  of  the 
villain. 

Not    so   long    ago   the    WGY    players 

delivered  the  comedy,  "Get  Rich  Quick 

Wallingford"  in  a  most  excellent  manner. 

The  story  of  the  play  has  to  do  with  the 

(Continued  on  page  62) 


32  Radio  Age  for  December,  1925 


What  the  Broadcasters  are  Doing, 


Radio  Finally  Links  Motion 


30,oooRadio 
and  Movie 
Fans  Crowd 
Theaters  to 
See  World's 
First  Radio- 
Cinema 


/"\VER  30,000  radio  and  motion  picture 
^~*  fans  crowded  Loew's  State  Theatre, 
and  fourteen  other  West  Coast  Theatres 
last  month,  to  see  and  hear  the  world's 
first  Radio-Cinema. 

A  full  page  of  history  was  written  that 
night,  for  it  was  the  first  linking  of  the 
"silent  drama"  with  the  human  "voice 
over  the  air."  Talking  pictures  had  at 
last  become  a  practical  reality. 

The  vast  crowds  which  jammed  the 
theatres  sat  almost  bewildered — so  un- 
canny seemed  to  be  the  perfect  synchroni- 
zation of  the  lip  movements  and  the  voice 
of  Norma  Shearer  and  Lew  Cody,  the 
principals  in  this  remarkable  experiment. 
Then  came  the  awakening  as  out  of  a 
dream  and  the  theatre  applause  became 
almost  deafening. 

It  was  an  undisputable  success,  which 
put  in  the  hall  of  fame  those  who  so 
earnestly  collaborated  in  making  the 
Radio-Cinema  practical — including 
Metro-Goldwyn-Mayer,  West  Coast  The- 
atres, Inc.,  local  radio  experimenters, 
Los  Angeles  Examiner  and  Station  KFI. 

"A  New  Epoch" 

r  1 1HE  attempt  to  synchronize  the  voice 
-*-  with  the  action  of  the  players  on  the 
screen  via  radio  marks  a  new  epoch  in 
the  amusement  world,"  said  Louis  B. 
Mayer,  vice-president  of  the  Metro- 
Goldwyn-Mayer  Corporation  following 
recent  experiment. 

"Metro-Goldwyn-Mayer  has  been  glad 
to  lend  every  cooperation  to  the  experi- 
ment as  have  Miss  Shearer  and  Lew 
Cody,  who  have  given  it  much  of  their 
time.  Most  of  the  work  came  under  the 
care  of  Douglas  Shearer,  brother  of 
Norma,  a  well  known  electrical  engineer. 
The  Los  Angeles  Examiner  is  to  be  com- 


Revealing  the  secret  of  radio-cinema!  Above  Norma  Shearer,  beautiful  movie 
star,  is  seen  broadcasting  through  the  K.FI  microphone,  while  her  ''speech"  is 
photographed  in  rolling  title  form  on  a  motion  picture  film.  The  KFI 
announcer  is  shown  at  the  control  board  giving  out  the  "cues."  The  machine 
in  the  foreground  is  a  combination  camera  and  projector. 


plimented  for  the  way  it  fostered  the 
experiment  as  is  also  KFI." 

After  weeks  of  experimentthestudio  and 
the  radio  mechanical  experts  declared  that 
100  per  cent  synchronization  of  the  human 
voice  with  motion  pictures  was  possible. 

Sharply  at  9  p.  m.,  August  24,  the 
Metro-Goldwyn-Mayer  Radio-Cinema 
was  put  on  the  air  over  KFI. 

On  the  stages  of  every  theatre  involved 
in  the  experiment,  a  powerful  receiving 
set  had  been  set  up.  The  operators  in 
each  of  the  theatre  projection  rooms  wore 
head-phones,  which  gave  them  the  metro- 
nome time  setting  cues  for  starting  the 
film  as  well  as  the  interval  cues  during 
the  run  of  the  picture. 

Literally,  the  operator's  duty  was  to 
beat  time  with  the  projection  crank  after 
starting  his  machine  with  the  signal  of 
the  Radio  studio  broadcasting  chimes. 
No  effort  was  made  to  present  an  elabor- 
ate play.  As  the  announcer  stated,  the 
only  effort  was  to  show  that  it  was  possi- 
ble to  synchronize  voice  with  the  move- 
ment of  the  player's  lips.  The  promotors 
of  the  project  proved  their  point.  With 
the  exception  of  one  or  two  instances 
where  operators  became  nervous  the 
results  were  remarkably  successful. 

A  Personal  Appearance 

NORMA  SHEARER  and  Lew  Cody, 
actually    talking    from    KFI,    were 
heard  in  the  various  .theatres  throughout 


Southern  California,  while  the  audiences 
watched  the  motion  pictures  of  them 
talking  with  the  same  true  effect  as 
though  it  were  a  personal  appearance. 
The  demonstration  opened  the  door  to 
conjecture.  The  Radio-Cinema  has  un- 
doubtedly arrived. 

Now  that  inventors  are  announcing  the 
control  of  radio  waves,  it  may  be  possible 
soon  for  a  group  of  theatres  to  present 
any  length  film  story  to  their  individual 
audiences  over  special  tuned  sets  without 
making  the  same  show  available  to  others 
who  have  not  paid  for  the  service. 

At  the  same  time  the  doors  also  opened 
to  the  inventive  genius  who  can  make  it 
possible  for  every  home  to  have  its  own 
talking  motion  pictures. 

At  the  first  public  demonstration  the 
entire  "secret"  of  the  Radio-Cinema  was 
laid  bare  to  the  audience  in  Loew's  State 
Theatre  through  a  special  act  which  was 
presented  on  the  stage. 

The  "act"  revealed  a  stage  set  which 
was  an  exact  replica  of  the  KFI  studio 
revealing  Norma  Shearer  and  Lew  Cody 
with  the  official  announcer  at  the  micro- 
phone. The  KFI  projection  machine  was 
there  throwing  a  picture  on  a  miniature 
screen  while  above  them  was  the  regular 
Loew's  State  screen. 

The  audience  was  rather  startled  to  see 
two  pictures  exactly  alike  unfolding  them- 


Radio  Age  for  December,  1925 


What  the  Broadcasters  are  Doing 


33 


Pictures  and  the  Human  Voice 


selves  on  two  different  screens.  The 
Loew's  State  orchestra  played  the  them- 
atic score  they  had  prepared. 

Then  came  that  part  of  the  experiment 
where  Miss  Shearer  and  Cody  arrived  at 
the  KFI  studio  and  actually  talked  "over 
the  air" — and  another  surprise  for  the 
audience.  Just  as  Mr.  Cody  stepped 
before  the  microphone  on  the  stage,  the 
picture  on  the  miniature  screen  dis- 
appeared and  a  rolling  title  appeared  in 
its  stead.  Lew  was  actually  reading  his 
lines  from  one  screen,  while  the  screen 
above  showed  the  movement  of  his  lips 
in  perfect  synchronization. 

Telling  'Em  the  How 

GLENN  RICE,  program  manager  at 
KFI  explained  in  terms  that  both 
radio  fans  and  the  public  could  easily 
understand  how  the  Radio-Cinema  had 
been  made  an  actuality. 

More  than  200  seats  had  been  reserved 
for  Metro-Goldwyn-Mayer  officials  and 
various  film  celebrities. 

Among  the  distinguished  guests  in  the 
audience,  were:  Sol  Lesser,  A.  Gore, 
M.  Gore,  Fanchon  and  Marco,  Hobart 
Henley,  director  of  "Slaves  of  Fashion," 
A.  M.  Bowles,  general  manager  of  West 


Coast  Theatres;  Louis  B.  Mayer,  Harry 
Rapf,  E.  J.  Mannix,  Irving  Thalberg. 
John  McCormick,  general  manager  of 
First  National  production  units;  Colleen 
Moore,  Dorothy  MacMail,  Constance  Tal- 
madge,  Anita  Stewart,  Bert  Lytell,  Milton 
Sills,  Claire  Windsor,  Lon  Chaney,  J.  H. 
Goldberg,  M.  R.  Rosenberg,  Fred  Niblo, 
Victor  Seastrom,  Tod  Browning,  Robert 
Leonard,  Aileen  Pringle  and  many  others. 


Old  timers  in  the  experimental  world 
will  remember  the  efforts  of  Edison, 
DeForest  and  a  host  of  others  who  have 
tried  to  competely  synchronize  the  voice 
and  the  picture;  the  amount  of  brain 
work  expended  in  the  years  past  on  this 
topic  would  seem  sufficient  to  operate 
goodness  knows  how  many  windmills  and 
other  mechanical  devices  if  such  energy 
were  translated  into  terms  of  mechanical 
or  electrical  energy. 

Unquestionably  the  end  is  near;  the 
contributions  of  Edison,  DeForest,  Jen- 
kins and  many  others,  are  piling  up. 
Each  independent  investigator  unearths 
something  of  value  which  is  bound  to  be 
of  benefit  to  the  project  as  a  whole.  A 
resum^  of  the  radio-cinema  in  its  entirety 
would   involve   too   much   space   at   this 


Linking  the  silent 
drama  with  the 
voice  of  the  air 
was  successfully 
accomplished  in 
Los  Angeles  re- 
cently. Norma 
Shearer  and  Lew 
Cody  are  "doing 
their  stuff"  on  the 
screen  for  the  fans 
the  theater, 
while  the  loud 
speakers  on  the 
stage  bring  in  the 
"voices"  from 
KFI,  in  perfect 
synchronization 
with  the  screen  ac- 
tion. The  film  was 
shown  in  fifteen 
different  theaters 
simultaneously. 


time,  but  needless  to  say  there  are 
indefatigable  workers  probing  the  pro- 
blem and  they  believe  success  can  be 
assured  very  shortly. 

What  the  public's  reaction  will  be,  is  a 
question  subject  to  the  most  violent 
debate.  We  can  all  remember  the  early 
movies  and  their  effect  on  the  public. 
They  were  laughed  at,  condemned,  finally 
reluctantly  accepted  as  one  of  the  evils 
of  modern  days.  Today  they  occupy  a 
prominent  niche  in  our  social  life. 

Perhaps  the  period  of  newness  and 
strangeness  of  the  radio  cinema  will  not 
be  as  long  as  that  attendant  upon  the 
ushering  in  of  the  first  movies.  Today 
we  are  accustomed  to  thinking  in  terms 
of  electricity  and  radio;  everything  is 
done  to  speed  up  our  work  and  our  pleas- 
ures to  crowd  more  into  each  hour. 
Under  these  conditions,  with  a  public 
already  partly  prepared  through  the 
wonders  of  radio,  the  radio-cinema  may 
not  encounter  such  obstacles  as  its  foster- 
parents  did. 

We  have  come  to  accept  our  film  favorites 
in  their  appearance  on  thesilver screen,  but 
will  we  care  for  them  so  much  when  their 
voice  issues  from  a  loud  speaker?  This 
is   a  point  which  time  alone  will  settle. 


34  RADIO  AGE  for  December,  1925 


What  the  Broadcasters  are  Doing 


NEW  VOICE  Appears  at  WDAF 


Doesn't  this  genial  countenance  look  able  to  lake  the  place 
of  the  "Merry  Old  Chief  of  WDAF's  nighthawks?  Mr. 
Fitzer  knows  broadcasting  and  he  has  a  voice  that  travels 
well  on  WDAF's  new  power.  He  promises  to  make  the 
famous  Night-hawks  "nuttier"  than  ever. 


H.  Dean  Fitzer 

New  Leader 

of  Famous 

Night-Hawk" 

Club  in 
Kansas  City 
»   Studio 


KANSAS  CITY,  MO.— There  is 
a  new  voice  being  heard  these 
days  and  nights  from  the  studio 
of  WDAF,  the  broadcasting  station  of 
The  Kansas  City  Star,  home  of  the 
famous  Nighthawks.  The  station's  new 
director  and  announcer  is  H.  Dean  Fitzer, 
succeeding  Leo  Fitzpatrick,  who  has 
gone   to   WJR,    Detroit. 

Mr.  Fitzer  is  a  baritone  and  formerly 
was  a  member  of  The  Star's  reportorial 
staff.  In  the  latter  capacity  he  has  for 
three  years  directed  the  Midwestern 
Zone  in  the  National  Oratorical  contest 
on  the  Constitution,  his  management 
of  that  popular  and  educational  project 
extending  from  Canada  to  the  Gulf  of 
Mexico  and  from  the  Mississippi  river 
to  the  Rockies.  Throughout  the  war 
Mr.  Fitzer  served  as  a  musician  aboard 
the  U.  S.  S.  Dixie,  stationed  in  foreign 
waters. 

Along  with  the  change  in  personnel 
at  the  WDAF  studio,  big  plans  are  in  a 
stage  of  development  for  the  station's 
future.  A  new  transmitter,  now  being 
installed,  will  give  WDAF  1,000  watts 
power,  twice  the  power  of  the  present 
station.  This  will  be  a  boon  to  operators 
of    crystal    sets    and    should    cause    the 


By 
GEORGE  GRAHAM 


station  to  be  heard  from  greater  dis- 
tances. London  has  heard  WDAF 
many  times  with  its  present  trans- 
mitter. 

New  Studio  Planned 

A     LARGE   studio   has    been  built  for 

-^*-  WDAF,  as  well  as  spacious  rooms 

for  the  operating  equipment.     With  the 


THE  NIGHTHAWKS  CHANGE 
HANDS 

The  famous  Kansas  City 
"  Nighthawks"  are  known  all  over 
the  world  for  their  eccentric  pro- 
grams. Under  the  direction  of 
"Merry  Old  Chief"  Leo  Fitz- 
patrick, the  '"'hthawk  club  has 
grown   to   a  I  «hip    of  over 

50,000   rad:' 

And  nov  r  changeth. 

Leo   Fitzy  s    to   WJR, 

and     Def  /hose     story 

is    given  ge,    bids    for 

your  fa 


exception  of  the  large  aerials  that  tower 
above  the  Star  building,  the  entire  station 
is  new.  Special  programs  ushered  in  the 
new  WDAF,  its  new  director  and  an- 
nouncer and  its  new  equipment. 

Type  programs  will  be  the  goal  under 
the  station's  new  direction.  Experience 
has  taught  that  radio  audiences  do  not 
agree  on  the  kinds  of  programs  they  prefer 
would  come  to  them  through  the  ether. 
And,  too,  jazz  to  classical,  all  within  a 
single  program,  is  an  inexcusable  con- 
glomeration. In  view  of  this,  Mr.  Fitzer 
is  planning  type  programs  for  certain 
definite   periods. 

Programs  for  the  housewives  will  be 
offered  mornings  and  afternoons;  a 
matinee  string  trio;  the  "School  of  the 
Air"  and  the  Tell-Me-A-Story  Lady  in 
the  early  evenings;  refined  ensemble 
music  for  the  dinner  hour;  Monday 
nights,  semi-popular  programs  in  "Around 
the  Town  with  WDAF;"  Wednesday  and 
Friday  nights,  programs  of  standard 
classical     music. 

Somebody  asked  where  does  the  jazz 
come  in?  "Stay  up  for  the  Nighthawk 
frolics  and  you'll  be  filled  full,"  comes 
the   answer   from    WDAF. 


RADIO  AGE  for  December,  1925 

Studio  Visitor  Qiven 

IMPRESSION 
OF  SPEED 

Trend  of  Radio  Design  in  Keeping  with 
Advances  in  Art  are  Seen  in  Sears- 
Roebuck  New  Studio  in  Hotel  Sherman 


The  Magazine  of  the  Hour  35 


SCIENCE  and  art  at  the  peak  of 
their  present-day  development  have 
been  fused  together  to  produce  the 
new  WLS,  the  Sears-Roebuck  Agricul- 
tural Foundation  Station,  Chicago.  The 
broadcasting  studio  just  completed  in  the 
new  Hotel  Sherman  Annex,  Chicago,  is 
an  example  of  an  entirely  original  and 
modern  type  of  art,  while  no  phase  of 
science  which  radio  wizards  have  been 
able  to  discover  has  been  left  untouched 
in  building  the  superpower  transmitting 
station  for  WLS  near  Crete,  Illinois.  The 
inaugural  program  on  the  new  Station 
was  given  Oct.  31. 

Water  Cooled  System 
This  station  will  give  the  last  word  in 
transmitting  efficiency.  The  transmitter 
is  5,000-watt  capacity  and  the  tubes  will 
be  10,000  watt  units.  A  specially  de- 
signed frequency  amplifier  system  will 
assure  the  holding  of  the  same  wave 
length  under  all  conditions  and  the  use  of 
the  capacity  coupling  will  reduce  possi- 
bility of  interference  with  other  stations, 
according  to  Curtis  D.  Peck,  chief  opera- 
tor. 

The  station  is  located  on  a  two  and  a 
half  acre  plot  on  the  Dixie  highway, 
just  south  of  Crete.  The  site  is  land- 
scaped and  beautified  with  hedges  and 
creeping  bent  grass  lawns.  Drives  and 
parking  space  for  visitors  also  are  pro- 
vided. Fifteen  miles  of  ground  wire  were 
plowed  in  rows  under  the  lawn,  very 
much  as  a  farmer  plants  potatoes. 
Merge  Beauty  and  Utility 
Utility  and  beauty  have  been  combined 
in  the  building  which  is  now  completed. 
The  building  contains  an  extra  large 
operating  room,  an  office,  an  attractive 
reception  room  for  visitors,  the  generator 
and  battery  rooms,  switch  closets  and  an 
entrance  hall.  The  most  up-to-date 
construction  has  been  employed  through- 
out with  extreme  emphasis  placed  on 
furnishing  perfect  transmission.  •  The 
metal  lath,  for  example,  is  joined  to- 
gether to  make  a  perfect  circuit  which 
will  insure  against  absorption  in  case  it 
should  ever  become  necessary  to  get 
down  to  lower  wavelengths.  An  elaborate 
hot  water  heating  system  has  been  in- 
stalled to  prevent  freezing  of  the  water 
in  cooling  tubes.  The  towers  are  200 
feet  high  and  forty  feet  at  the  base. 
They  can  easily  be  seen  as  far  distant  as 
the  Indiana  state  line 

A  series  of  exhaustive  tests  were  made 
by  the  Western  Electric  Company  before 
the  station's  inaugural  program. 


Same  Wave  Length 

The  wave  length  will  remain  the  same, 
344.6  meters  or  870  kilocycles.  The 
Army  experimental  call  letters  will  be 
A  Z  3. 

The  new  studio  is  located  on  the  6th 
floor  of  the  Hotel  Sherman  Annex. 
Alphonse  Ianelli,  well  known  interior 
decorator  developed  for  the  occasion  what 
might  well  be  called,  radio  art.  That  is, 
he  has  gone  to  the  radio  itself  for  his 
inspiration  in  designing  this  most  unique 
of  all  radio  studios.  Every  piece  of 
equipment  and  furniture,  the  walls, 
ceiling  and  lighting  fixtures  bear  out  the 
radio  motif  and  emanate  the  speed, 
intensity  and  universality  of  the  mys- 
terious forces  of  the  air.  Even  the  piano 
and  microphones  were  especially  designed 
to  carry  out  the  radio  theme. 

Twin  studios  have  been  provided. 
One,  55  feet  long  and  20  feet  wide,  is  for 
orchestras,  bands  and  dramatic  produc- 
tions, and  a  smaller  one  is  to  accommo- 
date soloists.  Separated  from  the  larger 
studio  by  a  plate  glass  window  is  the 
little  theatre  which  will  be  open  to  the 
general  public.  It  is  about  twenty  feet 
square  and  will  seat  fifty  people.  A 
loud  speaker  will  enable  the  audience  to 
hear  the  program,  as  well  as  watch  the 
artists  broadcast. 

Expressive  of  Speed 

Black,  red  and  silver  is  the  color 
scheme  for  these  unusual  rooms.  Ether- 
ial  energy  and  motion,  captured  by  the 
painter's  brush,  greet  the  eye.  Repre- 
sentation of  sound  waves  on  the  walls 
and  ceilings  give  the  visitor  the  impres- 
sion that  he  has  stepped  inside  of  Ein- 
stein's brain.  The  lightning  finger  of 
radio  speeding  through  the  dark  of  night 
is  expressed  in  the  black  woodwork 
touched  with  lines  of  silver  and  white. 
Black  and  red  chenille  carpetings  cover 
the  floor,  while  from  above,  indirect 
lighting  provides  startling  effects. 

A  reception  room  is  also  provided. 
This  has  a  distinctly  agricultural  back- 
ground, portraying  the  "voice  of  the 
farm"  which  the  educational  work  of 
the  Sears-Roebuck  Agricultural  Founda- 
tion is  carrying  from  coast  to  coast. 
A  large  mural  painting  representing  the 
four  corners  of  the  earth,  furnishes  the. 
key  note  of  the  room. 

In  addition  there  are  the  general 
offices,  the  operating  and  battery  rooms 
and  the  room  for  the  pipes  of  the  famous 
Barton  organ,  all  of  which  are  equipped 
in  the  most   modern  and  efficient  style. 


"By  his  toots  shall  ye  know  him"  might 
be  an  apt  paraphrase  covering  George  Hay, 
well  known  in  the  old  days  at  WMC, 
famous  later  at  WLS,  and  now  forsaking 
the  beautiful  new  WLS  studio  in  the 
Hotel  Sherman  to  become  announcer- 
extraordinary  of  the  new  radio  station  WSM 
at  Nashville,  Tenn. 

It  may  have  been  the  snow  up  here,  or 
the  plantation  melodies  down  there,  what- 
ever it  is  George  Hay  is  leaving  the  Sears 
Roebuck  station  to  return  to  his  former 
stamping  grounds  in  Tennessee,  where  he 
started  out  in  the  newspaper  game,  later  to 
become  a  leading  figure  among  announcers. 


When  informed  of  the  fact  that  George 
Hay,  "the  solemn  old  Judge"  of  WLS 
was  to  return  to  his  southern  heath  we 
immediately  came  to  the  conclusion  there 
must  be  a  conspiracy  on  between  the 
famous  southern  triumvirate,  the  Hired 
Hand  down  at  WBAP,  the  Little  Colonel, 
Lambdin  Kay  at  WSB  and  the  redoubt- 
able Hay  himself;  the  plot  of  which  we 
perhaps  will  never  know;  the  main  point 
is — try  to  get  these  three  gentlemen  away 
from  their  favorite  haunts. 

We  do  not  know  whether  it  is  the 
whistle  on  the  upper  part  of  this  page 
which  George  is  so  industriously  tooting 
or  what  it  is,  but  nevertheless  there  seems 
to  be  a  plethora  of  whistles  on  the  air 
these  evenings — vide  WSMB  at  New 
Orleans,  WSM  at  Nashville  (whence 
George  goes  with  his  own  whistle)  and 
perhaps  by  the  time  these  lines  reach  the 
public  gaze  there  may  be  several  more. 
You  can  imitate  the  whistle  but  you 
can't  duplicate  the  Judge. 


36 


RADIO  AGE  for  December,  1925 


What  the  Broadcasters  Are  Doing 


The  Dean  of  Radio  Adventurers 


Inborn 

Craving  for 

Adventure 

Led  this 

Fan  to 

Fame  in 

Radio 


A  Peep 
into  the 
Early  Life 
of  a 
Typical 
"Radio 
Pioneer" 


A  great  part  of  Mr.  Henninger's  early  career  was  spent  in  an  airplane. 
In  the  air  service  of  the  government  he  made  several  experiments 
in  inter-airplane  communication. 


WHEN  you  meet  up  with  a  fellow 
like  A.  F.  Henninger,  Jr.,  you 
immediately  sense  that  behind 
his  quiet  and  modest  ways  there  is  a 
temptestuous  career.  As  you  are  talking 
things  over  with  him  he  will  reluctantly 
allude  to  some  minor  characteristic  of 
the  natives  of  the  South  Sea  Isles  or -he 
might  give  you  a  brief  description  in 
about  ten  or  fifteen  words  of  what  an 
aviator  thinks  about  when  shells  are 
bursting  all  about  him. 

Radio  has  been  the  very  life  of  this 
prominent  engineer  for  the  past  fifteen 
years.  Radio  has  taken  him  around 
the  world;  has  caused  him  to  be 
hungry  and  cold  while  riding  a  dis- 
abled plane  in  the  rough  sea;  it  has 
made  him  a  general  or  something 
equally  grand,  in  the  army  of  a 
small  Central  American  Republic 
during  the  time  that  it  was  indulg- 
ing in  its  semi-annual  revolution. 
Radio  has  caused  him  to  be  lost  in 
the  wildest  of  jungles  for  two  weeks 
with  one  foot  made  totally  helpless 
by  a  revolutionist's  bullet.  Those 
are  adventures  that  few  men  alive 
today  can  equal,  but  frankly,  gen- 
erous reader,  it  took  18  working 
hours  of  cordial  questioning  and 
gentlemanly  prying  and  prodding 
to  ilicit  this  information  from  the 
lips  of  A.  F.  Henninger,  Jr. 

With  a  wireless  outfit  consist- 
ing of  a  telephone  receiver  res- 
urrected from  the  junk  box,  a 
small  piece  of  coal,  then  very  in- 
expensive, that  was  used  for  a  cry- 
stal detector  in  place  of  galena, 
some  wire  from  the  magnets  of  an 
old  Morse  telegraph  sounder  and 
some  iron  wire  for  the  antenna, 
Henninger  set  to  the  unusual  task 
of  constructing  some  sort  of  an 
apparatus  that  would  make  it  pos- 
sible for  him  to  hear  the  time 
signals  from  Arlington,  Virginia. 
Frankly,  folks,  success  was  not  to 
be  so  easily  achieved.  A  few  more 
months  of  experimentation  revealed 


By  WILLIS  ARNOLD 

the  need  of  a  loose  coupler,  consisting  of 
two  large  cardboard  tubes  wound  with 
wire  and  telescoping  one  into  the  other. 
Henninger  was  particularly  careful  to  see 
that  it  was  made  small  and  compact,  for 
when  these  tubes  were  extended  they  only 
covered  an  area  of  about  four  square  feet! 

AS    NO    doubt    you    already    realize, 
Henninger    is    not    the    type   of   in- 
ventor to  pace  up  and  down  his  labora- 


A.  F.  Henninger  at  work  in  his  private  lab- 
oratory,   where   he  spends  hours   at  a   time 
"fussing"  with  new  radio  ideas. 


tory  pulling  his  wavy  locks  with  un- 
rivaled enthusiasm  and  glee.  But  he 
could  have  well  afforded  a  few  minutes 
devoted  to  such  a  demonstration.  He 
had  actually  heard  the  time  signals  from 
Arlington! 

Of  course  it  can  be  said  that  the  same 
crystal  set  that  Henninger  constructed 
IS  years  ago  can  now  be  purchased  com- 
plete, ready  to  use,  for  less  than  a  dollar 
— and  the  whole  set  can  be  held  in  the 
palm  of  the  hand. 

During  the  early  part  of  the  war, 
Henninger,  devoted  his  thorough  know- 
ledge of  radio  to  helping  his  govern- 
ment. He  was  stationed  at  the 
Naval  Air  Station  at  Pensacola, 
Florida,  as  instructor  in  radio 
aviation.  When  not  out  riding 
disabled  airplanes  on  the  rough 
waters  of  the  Carribean  Sea,  he 
could  be  found  in  the  valuable  and 
costly  laboratories  that  the  govern- 
ment had  equipped,  doing  research 
and  pioneer  work  in  the  many  new 
phases  of  radio  aviation. 

He  was  later  transferred  to  a 
land  radio  station  and  later  to  take 
charge  of  the  model  radio  equip- 
ment on  a  new  destroyer.  It  might 
be  interesting  to  note  that  this 
destroyer  was  equipped  with  three 
transmitters,  including  a  radio  tele- 
phone, and  a  multiplicity  of  re- 
ceivers. Although  it  was  not  a 
particularly  valuable  instruction, 
Henninger  learned  the  art  of  bail- 
ing salt  water  out  of  a  radio 
receiver. 

Then,     as     prominent     novelists 
frequently  say,  his  mental  make-up 
demanded    a    change.       He    found 
himself  the  proud  possessor  of  an 
H  adventure  complex.     He  wanted  to 

free  himself.  Arming  himself  with 
a  commercial  operator's  license,  he 
left  for  New  York. 

He   had   heard   dreamy  tales  of 
Central  and  South  American    life. 
Others     had    told    him    of    gentle 
(Turn  to  page  60) 


RADIO  AGE  for  December,  1925 


Harold   Geiser,   director  of  the    Vincent   Lopez    Hotel    Statter    dance 

orchestra,  and  reproducing  record' organization  from    WGR,   Buffalo. 

Here  he  is  shown  all  dolled  up  before  the  microphone  and  ready  to 

slide  a  wicked  trombome  for  his  legion  of  listeners. 


What  the  Broadcasters  Are  Doing  37 

Step  up  and  Meet 

The 

PLAY  BOY  of  the 

DAKOTAS 

Here's  a  Radio  Artist  who 

Sees  More  in  His  Art 

than  the  Tom-Tom  of 

Jazz  Bands  and  the 

Sway  of  Dancers 

B?  LLOYD  S.  QRAHAM 


DO  YOU  know  WGR?  Do  you 
know  Harold  Gieser?  If  you 
know  either  one  you  know  the 
other. 

Also,  if  you  know  Harold  Gieser,  you 
also  know  good  jazz  music. 

A  friend  of  this  well  known  director 
of  the  Vincent  Lopez  Hotel  Statler  Dance 
orchestra,  Buffalo,  who  used  to  know 
him  as  a  boy  on  a  ranch  near  Aberdeen, 
South  Dakota,  and  who  is  one  of  the 
thousands  of  long-distance  admirers  of 
his  music  received  the  air-way,  has 
affectionately  dubbed  him  "the  play- 
boy of  the  Dakotas." 

The  pseudonym  sticks,  chiefly  because 
it  is  fitting.  Harold  Gieser  is  a  play- 
boy; that  is,  if  we  understand  the  term 
to  mean  one  who  has  a  joyous  and  philo- 
sophical viewpoint  on  life  and  who  takes 
a  great  deal  of  pleasure  in  making  it 
possible  for  others  to  play. 

Harold  Gieser  is  outstandingly  a 
leader  among  the  youthful  directors  of 
popular  orchestras  today.  He  is  well 
under  thirty  and  looks  it.  His  musical 
interpretions  have  the  joyousness  of 
youth  overflowing  in  them. 

A  Bunch  of  Mail 

'  1 1HAT  is  partly  the  reason  why  WGR 
-*-  receives  more  radio  mail  on  Harold 
Gieser  and  the  Vincent  Lopez  orchestra 
than  on  any  other  two  or  three  regular 
station  features  combined. 

Harold  Gieser's  gang  of  syncopators 
are  on  the  air  three  nights  each  week  for 


two  hours  each  time.  They  go  on  at 
11  o'clock,  Mondays,  Wednesdays  and 
Fridays,  and  continue  to  play  until  1 
o'clock  in  the  morning.  Supper-dance 
music,  they  program  it. 

But  there  is  another  reason  why  this 
orchestra  always  has  been  the  leading 
feature  of  WGR  and  why  the  fan  mail 
referring  to  it  steadily  increases. 

Harold  Gieser  takes  the  radio  audience 
with  tremendous  seriousness.  Osten- 
sibly the  orchestra  which  he  directs  is 
only  one  of  the  thirty  or  more  in  the 
famous  Lopez  combination.  Ostensibly 
it  is  engaged  by  E.  M.  Statler  to  play 
for  the  guests  in  his  pet  hotel — the 
hostelry  built  by  him  in  his  own  home 
town.  Ostensibly  broadcasting  privileges 
go  with  that  contract.  This  is  the 
arrangement  in  hundreds  of  hotels  and 
theaters  and  cabarets  throughout  the 
United  States  today. 

In  a  great  many  of  them,  too  many  of 
them,  the  orchestra  director  plays  what 
he  pleases  regardless  of  the  radio  audience. 
Microphones  are  placed  to  pick  up  what 
he  offers  the  patrons  of  the  place  which 
engages  him.  That  which  the  micro- 
phone picks  up  is  merely  a  by-product, 
and  many  directors  are  acutely  conscious 
that  it  is  a  by-product.  A  great  many 
directors  are  so  engrossed  in  their  own 
comparatively  little  job  of  entertaining 
a  few  hundred  people  during  an  evening 
that  they  cannot  take  the  uncounted 
thousands  out  in  the  air  with  much 
seriousness.       It     reminds    one     of    the 


aviator  who  had  his  little  son  up  in  the 
air.  They  were  flyin  g  over  a  city.  The 
boy  said  something  about  the  big  men  of 
the  city  but  the  wise  father  replied  that 
there  were  no  big  men  there,  some  were 
merely  smaller  than  others. 

A  "Man  of  Vision" 

"yiEWED  from  this  angle,  Harold 
»  Gieser's  conception  of  his  job  is  all 
the  more  important  and  interesting.  A 
learned  admirer  of  Gieser's  in  Buffalo 
put  it  another  way  when  he  said  that 
the  director  was  a  man  of  vision.  He  sees 
more  in  the  situation  than  the  mere, 
ordinary,  work-a-day  routine  of  it. 

When  he  manipulates  the  slide  trom- 
bone and  directs  his  men  he  sees  more 
than  the  richly  garbed  men  and  women 
out  at  the  tables.  He  catches  more  than 
the  sight  of  clinging  figures  weaving 
their  way  in  and  out  of  the  polished  tiled 
floor  of  the  Statler  to  the  strains  of 
"All  Alone."  He  sees  more  than  the 
rich  decorations,  the  snowy  linen,  the 
glittering  silver  and  crystal,  the  obse- 
quious waiters. 

There  may  be  something  in  the  fact 
that  he  was  born  and  raised  in  the 
Dakotas,  where  he  of  necessity  learned 
to  know  intimately  the  elemental  and 
fundamental  things  of  life,  that  enables 
his  inner  vision  to  see,  besides  those 
in  the  dining  room,  that  enormous 
other  audience  and  realize  what  good 
music  means  to  it. 

(Turn  to  page  62) 


38 


RADIO  AGE  for  December,  1925 


What  the  Broadcasters  are  Doing 


A  British  View  of  Broadcasting 


Capt.  L.  F.  Plugge  of 

Britain's    Radio 

Society  Speaks 

His  Mind 


IN  AMERICA  broad- 
casting started  some 
two  years  before  it  did 
in  this  country,  and  conse- 
quently we  in  England  had 
the  advantage  of  looking 
back  to  what  had  been  done 
over  there  before  facing  our 
problems.  This  advance 
trial  as  it  were,  wascertainly 
very  useful  to  us  in  many 
spheres.  One  of  the  princi- 
pal decisions  which  we  arriv- 
ed at  (and  the  American  ex- 
periences were  much  quoted 
in  this  respect),  was  the 
principle  of  placing  broad- 
casting in  the  hands  of  one 
central  organization  in  or- 
der to  assure  co-ordination 
a  n  d  t  o  avoid  the  chaos 
which  has  often  been  said  to 
exist  in  America  owing  to 
the  great  number  of  sta- 
tions controlled  by  a  like 
number  of  independent 
bodies. 

There  was  one  problem, 
however,  with  which  Ameri- 
ca was  not  faced,  and  this 
problem  in  Europe  we  are 
the  first  to  grapple.  It  is 
the  difficulty  arising  from 
the  close  neighbourhood  of 
so  many  different  countries 
in  which  different  languages  are  spoken 
and  in  which  different  laws  prevail. 
Except  for  Havana  stations,  United 
States  radio  amateurs  have  practically 
only  one  language  and  one  law  to 
contend  with.  The  South  American 
stations  separated  by  land  from 
the  States  have  only  been  received 
in  very  exceptional  circumstances,  and 
the  Canadian  stations,  except  for  La 
Presse,  which  is  a  bi-lingual  station,  use 
English. 

In  Europe  things  are  quite  different. 
Here  we  have  a  large  number  of  coun- 
tries very  close  to  one  another — a  twenty- 
four  hours  journey  can  hardly  be  made 
in  a  straight  line  without  visiting  three 
of  them.  They  all  have  different 
languages  and  different  laws,  and  it  is 
beginning  to  dawn  on  us  that  our  cen- 
tralisation of  broadcasting  as  compared 
with  America,  is  a  myth,  and  what  it 
is  supposed  to  avoid,  is  growing  greater 
every  day.  Wireless  knows  no  frontiers. 
It  appears  useless  for  a  geographically 
small  country  like  England  to  hope  that 
a  scheme  of  centralization  confined  to 
its  own  border  is  going  to  overcome  this 
chaos  said  to  be  detrimental  to  good 
reception. 


Capt.  L.  F.  Plugge,   member  of  the  General  Committee  of  the 

Radio   Society  of  Great  Britain,   and  European  authority  on 

broadcasting.     In  this  article  he  urges  an  international   radio 

conference  for  solution  of  outstanding  problems. 


The  Problem  of  Laws 

'T'HERE  then  is  the  question  of  law. 
■*■  Some  of  these  countries  have  laws 
quite  different  from  our  own.  Nothing 
can  stop  them  from  building  high  powered 
stations  within  very  short  range  of 
foreign  countries,  powerful  enough  to 
interfere  with  the  home  stations  and 
useful  enough  to  pour  their  propaganda 
into,  other  states.  There  is  a  common 
danger  here,  on  which  many  views  might 
be  taken. 

Either  centralisation  of  broadcasting 
authorities  is  no  good,  and  then  we  might 
discard  it  straight  away,  or  else  the  cen- 
tralisation which  the  B.  B.  C.  have 
achieved  in  England  should  in  the  largest 
measure  possible,  be  extended  to  the 
whole  of  Europe.  Co-ordination  should 
exist  among  the  various  broadcasting 
organizations.  They  should  come  to 
some  understanding  with  reference  to 
the  numerous  points  which  are  at  present 
looked  at  from  so  many  different  angles. 
How  can  this  be  done? 

The  first  thing  which  should  be  tackled, 
and  efficiently,  is  an  International 
Broadcasting  Conference,  and  this  Con- 
ference should  be  called  by  an  Independ- 


Problem  of  Conflicting 
Languages  Greatest 
that  Europe  has 
to  Face 


ent',  body.      That     the     B. 

B.  C.  are  in  touch  with 
Foreign  stations  there  is  no 
doubt,  several  of  the  Con- 
tinental programmes  have 
been  relayed  by  2L0,  and 
other  facts  have  shown  this. 
The  B.  B.  C.  carried  great 
weight  with  it  throughout 
the  length  and  breadth  of 
Europe,  but  it  would  be  a 
wrong  policy  for  the  B.  B. 

C.  to  call  such  a  Conference. 
There  is  already  a  feeling 
in  many  of  the  small  broad- 
casting organizations  of 
Europe  that  the  B.  B.  C.  is 
trying  to  enforce  its  will 
and  to  extend  its  British 
monopoly  to  other  coun- 
tries. These  other  coun- 
tries, jealous  of  their  inde- 
pendence, could  not  toler- 
ate such  an  attitude.  Every- 
thing should  be  done  so  as 
to  make  it  clear  that  it  is 
not  the  B.  B.  C.  that  is 
stage  managing  the  Con- 
ference. Paris  would  be  an 
excellent  seat  but  Geneva 
would  probably  be  better. 

It  would  be  good,  how- 
ever, that  the  calling  of  the 
Conference  should  come 
from  our  country.  We  are 
admittedly  the  country  in  Europe  where 
broadcasting  has  made  the  most  rapid 
strides,  and  it  is  natural,  therefore,  that 
the  calling  of  this  Conference  should  orig- 
inate from  a  recognised  body  in  this  coun- 
try. There  should  be  no  delay  in  the  calling 
of  this  Conference.  If  we  do  not  take  steps 
now,  France,  who  is  also  much  alive  to 
these  international  problems,  is  in  an 
excellent  position  to  call  such  a  Con- 
ference, and  we  will  lose  the  credit  of 
the  initiative. 

There  are  a  considerable  number  of 
subjects  which  will  be  suitable  for  dis- 
cussion at  this  conference,  and  although 
on  many  of  these  points  an  agreement  is 
not  likely  to  be  reached,  a  great  step  will 
be  made  forward  towards  harmony 
and  co-operation  which  unfortunately 
exist  in  so  small  a  degree  at  present. 


The  Question  of  KW 


of 


THERE  would  be  the  question 
power  to  be  allowed.  We  are  only 
at  present  using  something  like  15  kilo- 
watts on  our  most  powerful  broadcasting 
station,  and  the  average  number  of 
stations  rarely  use  more  than  a  couple 
of  kilowatts.  At  present  it  would  be 
(Turn  to  page  64) 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


Something  for  the  Beginner — 

A  3-Tube  Inductive  Coupled  Feed- 
back Receiver 

By  JOHN  B.  RATHBUN 


REGENERATION  still  stands  high 
in  the  regard  of  the  seasoned  rad- 
■  ioite  in  spite  of  the  frequency 
"dynes"  that  have  been  promoted  from 
time  to  time,  particularly  when  the 
matter  of  DX  is  of  paramount  import- 
ance. Tube  for  tube  and  dollar  for 
dollar  of  investment,  it  yields  the  great- 
est returns  of  any  circuit.  Another  point 
in  favor  of  the  simple  regenerative  cir- 
cuit lies  in  the  fact  that  it  is  easily  built 
by  the  beginner. 

Our  subject  for  the  present  blueprint 
section  is  a  three  tube  inductive  coupled 
feed-back  regenerative  detector  of  the  low 
loss  type  to  which  are  added  two  stages  of 
audio-frequency  amplification,  transfor- 
mer coupled.  With  this  combination  of 
tubes,  loud  speaker  operation  is  possible 
on  quite  long  distances  and  with  the  ex- 
tremely loose  coupling  used  between  the 
primary  and  secondary  of  the  antenna 
coupler,  the  circuit  will  be  found  very 
selective  and  comparatively  free  of  any 
tendency  toward  radiation.  The  main 
objection  to  the  use  of  a  regenerative 
circuit  in  crowded  centers  of  population 
has  been  the  radiation  by  a  single  cir- 
cuit or  tightly  coupled  regenerative. 

Two  tuning  controls,  only  one  of  which 
is  a  wavelength  control,  makes  it  easy  to 
tune  in  and  log.  The  second  control  is 
the  dial  on  the  shaft  of  the  tickler  coil 
by  which  the  plate  coupling  and  regenera- 
tion are  controlled.  The  single  rheostat 
used  for  regulating  the  filament  current 
of  the  detector  tube  is  not  particularly 
critical  and  therefore  does  not  need  suffi- 
cient Handling  to  put  it  under  the  classi- 

Original  Blueprints 


Copyright:  1925 wjtn  the  antenna  primary  coil  (LI),  the 

secondary  coil  (L2)  and  the  regenerative 

A    Regenerator    that     tickler  (Adjustable)  marked  (L3).    There 

0  are  a  number  of  three  circuit  tuners  on 

Affords  Clear  'DX'  the mazk* tMt aie f;uitfle f°r *hi4pur- 

pose,  the  Bremer-  fully,  Aero-Loil,  Bruno 
coil,  Uncle  Sam,  Sickles,  Etc.,  all  of  which 
are  of  the  "low-loss'  type  with  a  minimum 
of  insulating  material  in  the  electrostatic 
field  of  the  windings.  Air-spacing  be- 
tween turns,  bank-winding  or  wave- 
weaving  should  be  adopted  in  any  case 
in  order  to  reduce  the  distributed  capaci- 
ty, to  a  minimum.  Homemade  coils  in 
which  the  turns  are  packed  closely  side 
by  side  and  wound  on  a  massive  cylinder 
of  insulating  material  have  a  high  degree 
of  distributed  capacity  and  this  is  not 
desirable. 

To  control  the  feed-back  and  regen- 
eration, the  tickler  coil  (L3)  is  arranged 
so  that  it  can  be  turned  back  and  forth 
on  a  shaft  near  the  (F)  or  filament  end 
of  the  secondary  coil  (L2).  This  coil 
should  never  be  installed  at  the  grid  end 
(G)  of  the  secondary  for  every  movement 
of  the  tickler  will  then  upset  the  capacity 
relations  and  the  tuning.  Placed  at  the 
low  potential  end  (F)  of  the  secondary, 
which  is  grounded,  the  rotation  of  the 
tickler  has  little  if  any  effect  on  the  wave- 
length control.  While  this  may  seem  of 
little  consequence  tS>  the  beginner,  it  is 
really  very  important,  particularly  when 
working  on  faint  signals. 

In  the  same  way,  the  primary  coil  (LI) 
should  be  mounted  near  the  (F)  end  of  the 
secondary  or  away  from  the  grid  end  (G) 
(Turn  to  page  42) 


On  the  Loudspeaker 


fication  of  tuning  controls.  The  use  of 
an  untuned  or  aperiodic  primary  coil  in 
the  tuning  unit  does  away  with  the  an- 
tenna variable  condenser  commonly  used 
with  this  type  of  regenerative  circuit,  and 
by  providing  a  means  of  coupling  adjust- 
ment between  the  primary  and  secondary 
coils  for  determining  the  required  degree 
of  selectivity,  the  antenna  condenser  is  no 
longer  necessary. 

The  Circuit  Diagram 

T^IG.  1  on  the  first  blue  print  shows 
the  complete  schematic  circuit  of  the 
detector  and  audio  stages.  Starting  at 
the  left,  the  tube  (Tl)  is  the  detector 
tube,  (Tl)  is  the  first  audio  frequency 
amplifier  and  (T2)  is  the  second  audio 
amplifier.  The  rheostat  (Rl)  controls 
the  filament  current  of  the  detector  while 
the  two  audio  stage  filaments  are  main- 
tained at  a  constant  potential  by  the  two 
Amperites  (R2)  and  (R3).  A  rheostat 
can  be  used  for  the  audio  tubes  if  de- 
sired in  place  of  the  fixed  resistance,  but 
as  it  increases  the  complication  without 
adding  any  desirable  features  to  the  per- 
formance it  was  omitted  in  the  circuit 
shown. 


At  (CPLR)  is  the  three  circuit   tuner 
of  the  3-Tube  Regenerator  on  pages  40,  41,  44  and  45 


lirSSm 


42 


RADIO  AGE  for  December,  1925 


(Continued  from  page  39) 
of  the  secondary.  If  your  coil  is  not 
marked  with  connections  choose  the  open 
end  of  the  secondary  for  making  the  grid 
connection  to  the  detector  tube,  or  that 
end  that  is  farthest  away  from  the  pri- 
mary and  tickler  coils.  Where  possible, 
the  primary  coil  should  be  adjustable  in 
regard  to  the  secondary,  and  when  this 
adjustment  is  not  provided,  the  primary 
should  be  separated  from  the  secondary 
by  at  least  }4  inch  to  insure  selectivity. 
The  farther  (PI)  and  (SI)  are  separated, 
the  sharper  will  be  the  tuning  and  the 
more  selective  the  receiver  will  be.  If 
the  primary  is  more  than  J^  inch  from 
the  secondary,  it  is  likely  that  the  set 
will  be  too  selective  for  country  service 
unless  extreme  care  is  used  in  moving 
and  adjusting  the  wavelength  dial.  It 
may  be  made  so  selective,  in  fact,  that 
the  faint  stations  will  be  jumped  over 
without  any  indication  that  they  are  on 
the  air. 

At  (GC)  is  the  grid  condenser  in  the 
grid  circuit  of  the  detector,  and  con- 
nected across  the  ends  of  the  grid  con- 
denser is  the  grid  leak  (GL).  The  grid 
condenser  or  leak  can  either  be  of  the 
fixed  or  adjustable  type,  but  the  adjust- 
able leak  and  condenser  is  probably 
preferable  as  it  can  be  adjusted  to  meet 
the  exact  requirements  of  the  tube  used. 
Every  individual  tube,  even  when  of  the 
same  make,  has  its  own  particular  char- 
acteristics that  demand  certain  values  of 
capacity  and  leak  resistance.  When  the 
fixed  type  of  condenser  and  leak  are  used, 
the  condenser  should  have  a  capacity  of 
0.00025  m.f.,  and  the  leak  resistance  ap- 
proximately 1.0  megohm. 

One  of  the  factors  in  the  construction 
of  a  regenerative  set  is  that  a  positive 
bias  must  be  maintained  on  the  detector 
tube  (Tl)  so  that  it  is  properly  sensitive 
to  weak  incoming  signals.  In  other 
words,  the  "A"  battery  must  be  con- 
nected to  the  grid  return  circuit  (F)  in 
such  a  way  that  its  positive  pole  (+A) 
goes  toward  the  grid  leak  (GL),  thus 
permitting  a  very  small  flow  of  positive 
current  through  (GL)  to  the  grid  of  the 
tube.  This  has  been  accomplished  in  Fig. 
1  where  it  will  be  seen  that  the  (+A) 
connection  goes  to  the  grid  return  (F) 
and  hence  to  the  grid  post  (G)  through 
the  grid-leak  (GL).  Putting  a  negative 
bias  on  the  detector  tube  increases  the 
volume  of  local  stations  or  other  strong 
signals  butreduces  the  sensitivity  to  weak 
distant  stations.  Don't  be  misled  by  the 
greater  volume'on'local  stations  obtained 
by  a  negative  grid  bias. 

Tuning  to  Wavelength 

T^UNING  to  wavelength  is  accom- 
-■-  plishedTbyTthe  variable  condenser 
(CI)  having  a  maximum  capacity  of  from 
0.00035  m.f.  to  0.0005  m.f.  depending 
upon  the  type  of  coil  used.  This  should 
preferably  be  equipped  with  some  form 
of  vernier  dial  so'that  close  accurate  ad- 


justments can  be  made,  and  when  possi- 
ble, should  be  of  the  "straight-line-wave- 
length" or  "straight-line-frequency"  type, 
the  latter  to  avoid  crowding  of  the  200 
meter  band  of  stations  on  the  lower  end 
of  the  dial.  As  a  rule,  a  0.00035  m.f. 
condenser  will  completely  cover  the  band 
of  broadcasting  wavelengths  ranging  from 
200  to  600  meters  when  commercial  coils 
are  employed,  but  to  be  on  the  safe  side 
one  should  note  the  capacity  required  by 
the  makers  of  the  given  coil.  If  the  con- 
denser is  too  small,  the  receiver  will  not 
reach  the  higher  wavelengths.  If  it  is 
too  large,  it  is  likely  that  the  minimum 


Don't  Fail  to  Read  the 

Detailed    Description 

of  the 

"RADIO  AGE" 

MODEL 
RECEIVER 

In  This  Issue  of 
RADIO  AGE. 

Watch  future   issues    for    Im- 
provements of  this  unique  set. 


capacity  will  be  so  great  that  the  set  will 
not  go  down  to  200  meters  and  thus  will 
lose  the  greater  number  of  the  low  wave 
stations. 

In  connecting  the  variable  condenser 
(CI)  into  circuit  it  is  of  importance  to 
connect  the  stator  or  stationary  plates 
to  the  grid  (G)  side  of  the  secondary 
coil  with  the  rotary  plates  connected  to 
the  (F)  end.  If  this  should  be  reversed, 
there  will  be  trouble  from  "body  capaci- 
ty" as  the  grid  potential  would  then  be 
brought  out  along  the  shaft  close  to  the 
hand  when  adjusting  the  dial.  This  is 
about  the  thirtieth  time  that  this  con- 
structional feature  has  been  mentioned 
in  the  pages  of  Radio  Age,  but  as  the 
writer  ran  down  a  case  of  trouble  due  to 
reversed  rotor  last  week  it  is  thought  ad- 
visable to  again  call  the  attention  of  the 
builder  to  it.  In  the  diagram,  the  rotor 
plate  in  condenser  (CI)  is  indicated  by 
the  curved  line  while  the  straight  line 
represents  the  stator. 

As  an  additional  safe  guard  against  body 
capacity,  the  (F)  end  of  the  secondary 
coupler  coil  and  the  (-A)  battery  line  are 


The  Magazine  of  the  Hour 

grounded.  In  this  way,  the  batteries  and 
rotor  end  of  the  condenser  shaft  are 
brought  to  zero  potential  and  thus  high 
grid  potentials  will  not  be  affected  by 
moving  bodies  which  are  also  at  or  near 
zero  potential.  Body  capacity  effect,  or 
squealing  when  the  hand  is  placed  near 
the  dial,  is  the  most  annoying  trouble 
experienced  with  a  poorly  designed  re- 
ceiver. It  absolutely  prevents  you  from 
getting  distance  as  it  upsets  the  tuning 
every  time  that  you  place  your  hands  on 
the  dials,  and  further,  causes  nerve  racking 
shrieks  and  whistles  on  nearby  stations. 
Ordinarily,  a  "B"  battery  voltage  of 
22.5  volts  works  best  on  the  detector 
tube  for  all  around  service,  but  with 
201A  type  tubes  as  high  as  45  volts  can 
be  used.  Increasing  the  plate  voltage  of 
the  detector  tube  above  normal  makes 
the  circuit  unduly  critical  and  difficult 
to  tune  and  in  addition  makes  it  very 
noisy.  Greater  signal  strength  on  local 
stations  will  be  had  by  applying  from 
67.5  to  90  volts  on  the  plate  of  the  de- 
tector but  on  distant  stations  this  am- 
plifying quality  seems  to  be  lost  and  the 
increased  tendency  toward  "flopping 
over"  makes  it  difficult  to  get  real  dis- 
tance with  more  than  45  volts.  In  the 
figure,  the  detector  tap  to  the  "B"  bat- 
tery is  shown  at  22.5  volts. 

Audio  Frequency  Stages 

'yHE  PLATE  output  of  the  detector 
-*-  tube  passes  through  the  primary  coil 
(PR1)  of  the  first  audio  frequency  trans- 
former (AFT-1),  entering  the  transformer 
at  the  plate  post  (P)  and  leaving  at  the 
(B)  post.  This  transformer  can  be  any 
good  make  of  audio  frequency  transfor- 
mer having  a  turn-ratio  not  greater  than 
6.0,  and  preferably  not  greater  than  3.5. 
Ratios  greater  than  3.5  tend  to  cause  dis- 
tortion and  noise,  and  above  a  turn  ratio 
of  6.0  the  noise  increase  is  greater  than 
the  apparent  increase  of  amplification. 
The  secondary  coil  (SEC)  is  connected 
to  the  grid  post  (G)  of  the  first  audio 
tube  (T2)  at  post  (G)  while  the  (F)  post 
of  the  transformer  goes  to  the  (-C)  of 
the  biasing  battery  "C." 

Here,  the  matter  of  grid  bias  is  exactly 
reversed  for  we  require  a  strong  negative 
bias  on  the  grid  of  an  audio  amplifying 
tube  instead  of  the  positive  bias  used  on 
the  detector.  The  "C"  battery  provides 
this  negative  bias  and  with  90  volts  of 
"B"  battery  on  the  plates  of  the  ampli- 
fiers, about  4.5  volts  of  negative  bias  will 
be  required  from  the  "C"  battery.  This 
negative  bias  reduces  the  tendency  to- 
ward self-oscillation  or  regeneration  in 
the  audio  frequency  stages  and  thus  not 
only  reduces  noise  and  distortion  in  this 
circuit  but  also  increases  the  amplifica- 
tion without  the  expenditure  of  more  "B'! 
battery  Current.  In  fact,  the  "C"  bat- 
tery will  cut  down  the  "B"  battery  by 
about  half,  and  at  the  "C"  is  practically 
on  an  open  circuit  the  demand  on  this 
cell  is  practically  nil. 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


43 


At  (Kl)  is  a  bypass  condenser,  either 
of  the  fixed  or  adjustable  type,  which 
affords  a  free  passage  for  the  radio  fre- 
quency current  on  its  return  to  the  fila- 
ment circuit.  Its  capacity  of  approxi- 
mately 0.001  m.f.  is  sufficient  to  carry 
radio  frequency  current  but  is  not  great 
enough  to  transmit  an  appreciable  amount 
of  audio  frequency  current,  hence  the 
audio  phase  of  the  detector  output  passes 
through  the  transformer  while  the  R.  F. 
current  is  bypassed  around  the  primary 
coil.  This  at  least  reduces  the  amount 
of  radio  frequency  current  in  the  audio 
stages,  and  as  radio  frequency  current 
in  the  audio  tubes  causes  self-oscilla- 
tion and  noise  it  is  desirable  to  re- 
duce the  R.  F.  phase  to  the  lowest  possible 
amount  when  audio  amplification  takes 
place. 

Condenser  (Kl)  may  be  fixed  or  ad- 
justable, the  latter  type  being,  preferable 
for  the  reason  that  the  capacity  can  be 
adjusted  so  that  a  minimum  of  audio 
current  is  short  circuited  through  the  by- 
pass condenser.  This  is  not  a  variable 
condenser  (represented  on  the  panel  front 
by  a  dial)  but  is  a  special  type  of  "Ad- 
justable" condenser  designed  for  this  pur- 
pose. When  once  adjusted  to  the  circuit, 
no  further  attention  is  required. 

A  fixed  condenser  (K2)  having  a  capaci- 
ty ranging  from  0.002  m.f.  to  0.006  m.f. 
is  connected  across  the  (  +  B)  and  (-A) 
lines  to  reduce  the  radio  frequency  re- 
sistance in  the  "B"  batteries  when  the 
batteries  get  old  and  partly  dried  up. 
The  value  of  the  condenser  is  not  critical, 
and  probably  no  advantage  will  be  noted 
when  the  "B"  is  new  and  fresh,  but  when 
the  batteries  get  old,  condenser  (K2)  will 
show  a  marked  improvement  in  perform- 
ance. It  is  then  easier  for  the  radio  fre- 
quency current  to  pass  through  the  capac- 
ity of  (K2)  than  through  the  high  resist- 
ance of  the  old  "B"  batteries.  A  capacity 
of  0.006  m.f.  will  insure  proper  bypassing 
under  all  conditions  without  diminishing 
the  strength  of  the  R.  F.  phase. 

After  amplification  in  the  first  audio 
stage,  giving  greatly  increased  sound  vol- 
ume, the  output  of  the  first  audio  tube 
(Tl)  is  passed  through  the  primary  coil 
of  the  second  audio  transformer  (AFT-2). 
The  posts  of  this  transformer  are  marked 
in  proper  relation  to  the  balance  of  the 
circuit,  the  post  (P)  going  to  the  plate 
(P)  of  tube  (Tl)  and  post  (B)  going  to 
the  (+90)  post  of  the  "B"  battery.  For 
proper  amplification,  90  volts  will  be  re- 
quired on  the  plates  of  both  audio  fre- 
quency tubes  (T1-T2)  and  when  the 
voltage  drops  much  below  80  volts  due 
to  an  exhausted  battery  there  is  a  pro- 
nounced falling  off  in  the  volume. 

The  (F)  post  of  the  secondary,  trans- 
former (AFT-2),  is  connected  to  the  (-C) 
of  the  "C"  battery  so  that  this  stage  is 
also  given  a  negative  bias  by  the  same 
battery.  The  (G)  connection  of  the 
secondary  goes  to  the  grid  of  the  second 
audio  tube  (T3)  as  usual,  and  this  com- 


pletes the  connections  in  the  audio  stages. 
No  intermediate  jacks  are  used,  only  the 
output  jack  (Jl)  connected  to  the  second 
audio  frequency  stage. 

Picture  Diagram  Layout 

TTMG.  2  is  the  same  circuit  drawn  out 
-*-  in  picture  for  as  it  really  appears. 
All  of  the  parts  shown  in  Fig.  2  are  given 
the  same  letters  and  figures  as  corre- 
sponding parts  in  Fig.  1  so  that  the 
relation  between  the  two  drawings  can 
be  easily  followed.  We  are  looking  down 
on  the  set  with  the  panel  edge  next  to  us, 
and  the  panel  can  be  easily  identified  by 


A    Treasure   of 

Blueprints! 
— may  be  found 
in  back  issues  of 
"Radio  Age,  the 
magazine  with 
blueprints,"  see 
page  50  for  list  of 
subjects  in  back 
number  blue- 
print sections. 
30  cents  a  copy. 


the  dials  and  rheostat  knob  drawn  on  the 
outer  face  of  the  panel.  Starting  from 
the  left  we  have  in  order,  the  tuning  coil 
unit,  the  variable  condenser  (CI),  the  de- 
tector rheostat  (Rl)  and  then  the  audio 
frequency  stages  at  the  extreme  right. 
The  output  jack  (Jl)  is  at  the  right  end 
of  the  panel  with  the  battery  switch  (SW) 
near  the  center.  The  battery  switch  is 
also  shown  at  (SW)  in  Fig.  1,  so  placed 
that  it  opens  the  "A"  battery  circuit. 
This  is  necessary  as  the  audio  stages  are 
not  provided  with  rheostats  and  some 
means  must  be  provided  to  cut  them  out 
of  circuit  simultaneously  with  the  de- 
tector tube. 

This  receiver  is  "back-connected"  with 
all  outside  wires  connected  to  connection 
strips  fastened  to  the  rear  edge  of  the 
baseboard.  At  the  left  is  the  connection 
strip  carrying  the  antenna  post  (ANT) 
while  at  the  right  is  the  battery  con- 
nection strip  with  the  posts  (-f-A),  (— B), 
(+22)  and  (+90).  This  arrangement 
makes  installation  very  simple  and  con- 
venient and  avoids  a  clutter  of  wires 
around  the  front  of  the  instrument  which 


is  always  in  evidence  with  a  front  con- 
nected set.  Holes  must  be  drilled  in  the 
back  of  the  cabinet  to  accommodate 
these  wires,  but  in  no  case  attempt  to 
run  the  ground  wire  and  antenna  lead- 
in  wire  through  the  same  hole.  For  the 
best  results,  a  separate  hole  should  be 
drilled  for  each  wire,  the  hole  being 
placed  directly  opposite  to  the  binding 
posts  so  that  it  will  lead  directly  into 
the  post. 

Owing  to  the  form  of  the  coil,  and  to 
the  fact  that  it  is  standing  with  its  axis 
in  a  vertical  line,  it  has  been  rather  diffi- 
cult to  show  the  actual  connections  at 
this  point  as  they  actually  appear.  The 
connections,  however,  have  been  lettered 
as  they  actually  are  marked  on  the  manu- 
factured coils,  and  this  marking  should  be 
followed.  One  rotor  connection  goes  to 
the  plate  of  the  detector  tube  (Tl)  and 
the  other  goes  to  the  (P)  posts  of  the  first 
audio  frequency  transformer  (AFT-1). 
These  are  marked  respectively  (rP)  and 
(rB)  in  the  drawing. 

Connection  from  the  antenna  goes  to 
the  primary  of  the  tuner  at  (A),  and  the 
ground  to  (GND).  The  grid  to  the  grid 
condenser  is  indicated  by  post  (G)  while 
the  reamining  post  (F)  goes  to  the  (-A) 
line.  All  of  these  connections  can  be 
traced  through  in  Fig.  1  if  the  reader 
is  familiar  with  radio  symbols. 

By  careful  arrangement,  a  7*xl4"x%' 
panel  can  be  used,  but  a  7'xl8'x%' 
panel  gives  more  room  and  is  easier  for 
the  beginner  to  wire.  The  baseboard 
should  be  deep  enough  to  fit  closely  in 
a  cabinet  having  a  depth  of  eight  inches. 
Most  of  the  standard  cabinets  have  an 
inside  depth  of  eight  inches  but  this 
should  be  checked  up  with  the  cabinet 
that  you  intend  to  use  and  the  base- 
board cut  accordingly. 

It  is  a  good  plan  to  install  the  variable 
condenser  (CI)  with  the  stator  or  sta- 
tionary plates  uppermost  and  with  the 
rotary  plates  turning  out  from  under- 
neath. This  will  afford  protection  to  the 
unsupported  rotor  plates  and  at  the  same 
time  will  prevent  so  much  dirt  from  fall- 
ing into  the  condenser.  Turned  the  other 
way  about,  the  rotor  plates  are  likely  to 
be  struck  accidentally  and  injured. 

When  the  plates  are  completely  dis- 
engaged, the  capacity  should  be  at  a  mini- 
mum and  in  this  position  (or  close  to  it) 
the  lowest  wave  lengths  are  received.  The 
dial  should  now  be  moved  around  on  the 
shaft  until  a  reference  scratch  on  the 
panel  points  to  the  (O)  division  on  the 
dial.  Further  experiment  will  indicate 
whether  the  true  zero  point  lies  at  either 
side  of  the  apparent  zero  and  then  cor- 
rections can  be  easily  made  by  slightly 
shifting  the  dial.  At  maximum  capacity 
and  highest  wavelength,  the  plates  are 
fully  meshed  with  the  indicator  pointing 
to  the  (100)  division  on  the  dial.  As 
explained  before,  a  vernier  dial  is  highly 
desirable  on  this  sort  of  set  so  that  the 
(Turn  to  page  46) 


93W  OS  0 


mooo'ooi 


•93W  01 


X^B 


\mooo'oo\ 


46 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


(Continued  from  page  43) 
utmost   selectivity   can    be   attained    by 
small  accurate  dial  movements. 

Wiring  Instructions 

IT'OR  a  long  time,  radio  set  builders 
*-  have  employed  bare  tinned  copper 
bus-bar  for  wiring  the  sets,  the  bus-bar 
being  square  cross-section  instead  of 
round.  This  was  sufficiently  rigid  to 
support  its  own  weight  for  a  consider- 
able distance  and  when  securely  soldered 
to  the  connection  lugs  gave  a  very  rigid 
wiring  structure.  However,  this  system 
had  its  faults  when  used  by  the  amateur. 
It  was  difficult  for  the  novice  to  arrange 
the  wiring  in  a  simple  manner  in  accord 
with  the  arrangement  of  the  apparatus, 
and  unless  great  care  was  taken  it  was 
difficult  to  avoid  short  circuits  and 
grounds.  Further,  the  soldering  was  not 
always  of  the  best  and  the  total  result 
was  that  many  circuit  troubles  developed 
which  were  due  to  poor  construction, 
poor  layout  and  still  poorer  manipula- 
tion of  the  soldering  copper. 

The  introduction  of  the  rubber  covered 
flexible  strand  wire  did  much  to  reduce 
wiring  troubles  for  the  rubber  insulated 
wire  could  be  easily  run  in  any  direction 
regardless  of  the  arrangement  of  the  ap- 
paratus. The  condensers,  sockets,  trans- 
formers and  tuning  coils  could  be  put 
into  the  most  advantageous  positions 
without  it  being  necessary  to  make  com- 
promises on  account  of  the  rigid  bus 
wiring.  Short  circuits  became  almost  a 
thing  of  the  past,  and  by  properly  run- 
ning the  wires  they  were  made  almost 
invisible  instead  of  being  the  most  prom- 
inent features  of  the  receiver.  For  this 
reason  I  recommend  that  rubber  covered 
flexible  strand  be  used  for  wiring,  and 
this  wire  can  no  be  found  at  nearly  any 
radio  store. 

For  ease  in  making  connections,  the 
rubber  covering  should  be  of  the  type 
used  in  telephone  switchboard  wiring,  a 
wire  having  an  insulation  that  is  easily 
stripped  off  at  the  ends  for  making  con- 
nections. The  solid  wire  with  the  ad- 
hering type  of  rubber  insulation  used  for 
electric  light  wiring  is  not  suitable.  For 
ease  in  making  connections,  copper  eye- 
lets or  connection  lugs  should  be  clamped 
to  the  ends  of  the  flexible  strands  so  that 
a  good  solid  electrical  contact  will  be  had 
at  the  connection  posts.  With  the  lugs 
firmly  clamped  to  the  wire  it  is  a  simple 
matter  to  solder  them  firmly  into  place. 

Fig.  3  shows  the  center-to-center  di- 
mensions for  the  panel  mounted  apppa- 
ratus.  The  outlines  of  the  parts  hidden 
behind  the  panel  ate  shown  dotted  so 
that  the  purpose  of  the  various  controls 
can  be  easily  seen.  As  the  screw  holes  of 
the  different  makes  of  radio  parts  em- 
ployed vary  somewhat,  these  holes  are 
not  dimensioned,  but  with  the  apparatus 
centers  located  it  should  be  a  simple  matter 
to  layout  these  special  screw  centers  about 
t:  ;  center  lines  shown  on  the  drawing. 


The  panel  itself  should  not  be  less  than 
%?  as  thinner  panels  make  it  difficult 
to  fasten  standard  parts  in  place,  the 
screw  and  bushing  of  the  majority  of 
parts  being  designed  for  %"  to  J£* 
panel  thicknesses.  Any  standard  panel 
material  can  be  used  such  as  Bakelite, 
Radion,  Dilecto,  etc.,  but  wood  should 
be  avoided  even  for  temporary  construc- 
tions, unless  it  has  previously  been  boiled 
in  paraffine.  The  appearance  of  the  panel 
is  greatly  enhanced  by  having  the  names 
of  the  controls,  the  arrows  and  indicator 
marks  engraved  directly  on  the  face  of 
the  panel.  This  can  be  done  at  a  small 
expense  by  many  of  the  radio  houses  when 
they  are  supplied  with  a  sketch  showing 
the  names  and  their  location. 

Resistance  Amplification 

FIG.  4  is  a  schematic  diagram  of  the 
same  detector  circuit  supplied  with 
resistance  coupled  audio  frequency  am- 
plification in  place  of  the  audio  trans- 
formers. This  requires  a  third  tube  in 
the  audio  stages  so  that  we  now  have 
four  tubes  instead  of  the  three  previously 
used.  In  many  cases  the  results  obtained 
with  the  resistance  coupling  amply 
justify  the  additional  tube  particularly 
when  tone  quality  is  a  matter  of  im- 
portance. 

Inter-stage  audio  coupling  in  the  audio 
circuit  is  had  by  the  0.006  m.f.  fixed  con- 
densers (M1-M2-M3)  that  extend  be- 
tween the  output  of  one  tube  and  the 
grid  of  the  following  tube.  Resistors  (rl- 
r2— r3)  connect  between  the  plate  and  the 
(  +  B)  line,  and  the  drop  of  potential  over 
these  resistors  is  responsible  for  the  am- 
plification. The  resistors  have  a  high  re- 
sistance as  indicated  on  the  drawings  but 
their  resistance  is  much  less  than  that  of 
the  grid  leaks  (rL)  connected  on  the  grid 
side  of  the  coupling  condensers.  The 
grid  leaks  give  a  negative  bias  to  the 
grids  of  the  three  audio  tubes  and  their 
value  is  marked  on  the  drawing. 

When  the  201A  type  of  tube  is  used 
with  resistance  amplification,  a  plate 
voltage  of  135  volts  is  necessary  on  the 
plates  for  maximum  results,  but  with  the 
new  tubes  developed  especially  for  re- 
sistance coupled  amplification  the  usual 
90  volts  can  be  used  with  perfect  satis- 
faction. A  potential  of  90  volts  with 
201A  tubes  gives  less  volume  but  the 
tone  is  still  good  although  the  volume 
is  somewhat  reduced. 

While  the  resistance  of  the  resistors 
will  give  good  results  under  nearly  all 
ordinary  conditions,  yet  there  is  always 
some  optimum  value  that  will  give  the 
best  performance  with  the  given  tubes 
and  units  used  in  the  circuit.  To  insure 
the  best  all  around  results  it  will  be  best 
to  try  a  number  of  different  resistors  un- 
til the  best  value  is  determined.  While 
the  grid  leak  values  are  not  critical  yet 
there  is  a  noticeable  difference  when  dif- 
ferent leaks  are  used,  and  it  will  usually  be 
found  that  a  different  leak  will  be  required 


in  each  of  the  resistance  coupled  stages. 

While  the  dry  battery  tubes  such  as 
the  WD-12  or  the  "199"  type  can  be 
used,  yet  the  storage  battery  tubes  such 
as  the  201 A  will  always  give  the  greatest  i 
volume  and  the  best  all  around  results. 
The  distance  obtained  on  the  phones  will 
be  about  the  same  with  both  classes  of 
tubes  but  the  volume  of  the  dry  battery 
tubes  is  greatly  inferior  to  that  of  the 
0.25  ampere  type.  The  volume  produced 
by  the  "199"  tubes  can  be  greatly  aug- 
mented by  the  addition  of  the  new  UX- 
120  dry  cell  tube  in  the  last  stage  of  the 
transformer  coupled  receiver.  Similarly 
the  use  of  the  UX-112  or  the  Daven 
Mu-6  in  the  last  stage  of  a  storage  bat- 
tery operated  set  will  increase  the  volume 
over  that  obtained  by  a  201A  in  the  last 
stage.  The  latter  tubes  take  0.5  ampere 
at  6  volts  or  just  twice  the  current  taken 
by  the  201A. 

The"UV200"  tube,  gas  filled,  is  probably 
more  sensitive  than  the  201A  in  detecting 
distance  but  it  is  also  more  critical  and 
difficult  to  control.  It  takes  more  current 
than  the  201A  and  requires  very  careful 
filament  current  adjustment,  but  it  will 
often  bring  in  stations  with  a  regenerative 
circuit  that  will  never  be  found  with  the 
201A.  The  "200"  tube,  however,  is  not 
an  amplifier  and  can  only  be  used  as  a 
detector  at  (Tl). 

The  Antenna  and  Ground 

An  aerial  from  60  feet  to  75  feet  long, 
hung  more  than  35  feet  above  the  ground 
will  be  found  most  suitable  for  this  set. 
It  is  long  enough  to  catch  distant  stations 
successfully  and  yet  is  not  so  long  that 
the  selectivity  is  impaired.  An  aerial  of 
excessive  length  is  as  bad  as  an  aerial 
that  is  below  normal  length  for  the  long 
aerial  will  seriously  interfere  with  the  se- 
lective properties  of  the  receiver  and  in 
these  days  of  congestion  this  is  as  bad  as 
not  receiving  the  station  at  all.  The  aerial 
should  be  hung  well  out  in  the  open  or 
else  at  least  seven  feet  above  the  top  of 
a  flat  top  roof  in  case  that  the  wire  can- 
not be  hung  in  the  yard  and  away  from 
the  building. 

The  ground  is  nearly  of  as  much  im- 
portance as  the  antenna.  The  best 
ground  is  had  by  clamping  the  wire  to  a 
water  or  steam  pipe,  the  pipe  being  clean- 
ed free  from  paint,  rust  and  grease  before 
the  clamp  is  applied.  In  case  the  build- 
ing is  not  piped  for  water,  the  ground  can 
be  made  by  driving  a  steel  pipe  or  rod 
into  the  ground  until  it  strikes  perma- 
nently moist  earth.  A  copper  plate  drop- 
ped into  a  well,  hung  so  low  that  it  is 
well  below  the  water  level  at  all  times  is 
also  a  method  of  making  a  ground.  Never 
use  a  gas  pipe  for  a  ground  for  the  reason 
that  the  house  gas  pipes  are  generally 
insulated  from  the  meter  and  the  chan- 
delier is  insulated  from  the  house  pipes. 
Of  course,  this  would  interrupt  the 
primary  current  and  cause  trouble  with 
the  operation  of  the  set. 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


47 


HooXc~ 


'PHE  material  appearing  under  the  title  "Pickups  and  Hookups  by  Our  Readers"  in  RADIO  AGE,  is 
A  contributed  by  our  readers.  It  is  a  department  wherein  our  readers  exchange  views  on  various  cir- 
cuits and  the  construction  and  operation  thereof.  Many  times  our  readers  disagree  on  technical  points 
and  it  should  be  understood  that  RADIO  AGE  is  not  responsible  for  the  views  presented  herein  by  con- 
tributors, but  publishes  the  letters  and  drawings  merely  as  a  means  of  permitting  the  fans  to  know  what 
the  other  fellow  is  doing  and  thinking. 


Conducted  by  Fred  Hill 

THE  radio  bacillus  apparently  does 
not  confine  its  manifestations  to 
the  male  gender,  as  the  following 
letter  from  Mrs.  Howard  P.  Crosby,  78 
Main    St.,   Fairfield,    Maine,  will   show: 

"Yes,  I  think  there  are  at  least  a  few 
women  who  take  much  interest  in  not 
only  radio  and  its  progress,  but  also  in 
the  RADIO  AGE.  I,  as  well  as  my  hus- 
band,  take   great   pride  and   interest   in 

our  set.     We  had  a  R in  the  first 

place  and  as  all  the  parts  were  metal 
they  seemed  to  be  of  a  mongrel  type  so 
we  took  it  all  apart  and  then  I  started 
to  rebuild  one  to  suit  ourselves.  My 
husband  and  I  made  a  set  and  it  was  far 
superior  to  the  old  one.  Later  we  thought 
we  could  improve  it  so  we  made  a  three 
tube  regenerative  set  consisting  of  one 
regenerative  detector  and  two  stages  of 
transformer  coupled  audio  amplification. 
We  have  a  100  foot  aerial  and  with  a 
counterpoise.  I  am  wondering  if  my 
list  of  stations  which  I  am  enclosing 
will  entitle  me  to  a  Dial  Twister's 
button." 

Goshamighty!  The  list  the  lady  sends 
in  is  four  pages  long,  typewritten,  and 
covers  everything  from  hearing  the 
chimes  in  Westminster  Abbey  from  2LO 
to  everything  on  the  North  American 
continent.  Such  energy  can  not  long  go 
unrewarded  and  as  a  starter  we  are  for- 
warding two  DT  buttons  to  Mrs.  Crosby, 
one  for  herself  and  the  other  for  Hubby. 
If  our  better  half  scampered  ethereally 
around  after  DX  in  such  a  manner  there 
is  one  column  conductor  who  would  have 
to  depend  upon  the  one-arm  lunch  stands 
for  subsistence,  but  perhaps  Mr.  and 
Mrs.  Crosby  have  some  sort  of  a  watch- 
and-watch  system  as  at  sea;  the  Mrs. 
watching  the  kitchen  and  the  radio  and 
the  Mr.  watching  the  clock.  We  would 
like  to  have  more  letters  like  the  fore- 
going since  we  believe  there  are  hosts  of 
married  radio  fans  who  both  take  a  keen 
interest  in  the  game.  Some  comparison 
to  the  old  days  when  the  wife  used  to 
threaten  divorce  proceedings  simply  be- 
cause we  spilled  a  quart  of  hot  paraffine 
on  the  gas  range  while  we  were  doping 
up  some  long  wave  coils! 


Now  from  the  nation's  Capitol,  a  letter 
from  William  C.  Peace,  126  Seaton  Place, 
Washington,  D.  C,  who  constructed  a 
two  tube  ultra-audion  from  the  March 
issue  of  Radio  Age,  added  one  stage  of 
audio  and  hopped  after  the  DX  signals. 
He  says  he  could  not  detune  the  locals 


M.  J.  Sahanel 

3917  Grand  Blvd. 

Chicago,  111. 


CONTRIBUTORS 

George  H.  Hawley 

69  Walnut  Ave. 

Roxbury,  Boston,  Mass. 

DIAL  TWISTERS 


Carl  Streiferd 

Braintree, 

Mass. 


George  Balta 4226  Todd  Ave East  Chicago,  Ind. 

George  Morrow Radio  8DTN Salem,  Ohio 

Leon  C.  O'Connor 47  Browenell  Ave... ..Hartford,  Conn. 

Frank  Wiles 110  North  9th  St.    .Lamar,  Colo. 

Harold  Bassett 216  North  Tower Centralia,  Wash. 

John  D.  Zahn Canal  Winchester,rO. 

Robert  Sieglinger 120  East  90th  St.  ....Chicago,  111. 

J.  P.  Morrison,  Jr 1711  South  Peoria.-Tulsa,  Okla. 

Mr.  and  Mrs.  H.  P. 

Crosby 78  Main  St Fairfield,  Me. 

Ralph  E.  Riley 1711  5th  St Oakland,  Calif. 

William  C.  Peace 126  Seaton  Place Washington,  D.  C. 

G.  V.  Skal Ober-Schreiberhau.... Alter  Baudenweg,  Ger. 

Lloyd  Wilson .663  Fairview  St Oakland,  Calif. 

F.  J.  Ferguson 2635  East  69th  St.  ..Cleveland,  Ohio 

Ralph  Litch._ Hudson,  S.  D. 

G.  A.  Winkle 223  Old  50th  St Birmingham,  Ala. 


but  between  the  hours  of  11  p.  m.  and 
3  a.  m.  he  dragged  down  quite  a  bunch 
of  stations,  to  say  nothing  of  a  flock  of 
amateur  signals.  Pretty  tough  on  a 
chap  who  has  to  stay  up  until  milk  time 
for  stations,  so  to  assuage  somewhat  his 
feelings  over  such  hard  lines  we  are  en- 
rolling Mr.  Peace  in  the  fraternity  of 
Dial  Twisters.     Peace  be  to  his  radio! 


There  seems  to  be  a  Destiny  that 
shapes  our  ends,  after  all.  We  thought 
at  first  the  makers  of  panels  would  soon 
have  to  go  out  of  business.  But  now  we 
have  found  out  how  their  annual  output 
is  always  taken.  The  condenser  manu- 
facturers are  the  best  friends  of  the  panel 
makers.  These  remarks  are  as  a  result 
of  a  three  hour  session  in  the  lab.  last 
night  changing  from  one  set  of  con- 
densers to  another  on  our  test  set.  In 
all  the  condensers  in  our  possession  not 
a  one  would  fit  in  holes  meant  for  an- 
other type.  Consequently,  not  having 
any  putty,  it  was  necessary  to  junk  every 
panel  when  putting  in  a  new  type.  If 
some  genius  would  only  invent  a  patent 
holding  device  which  would  accommo- 
date every  conceivable  combination  of 
condenser  holes  we  would  breathe  easier. 
We  still  have  a  great  respect  for  the  man 


who  designed  the  single  hole  mounting 
for  condensers  and  we  believe  the  fra- 
ternity is  with  us  on  this  subject.  And 
while  on  this,  some  day  we  hope  to  see 
the  dial  manufacturers  all  agree  upon  a 
clockwise  rotation  for  dials;  wouldn't 
it  be  a  great  world  if  the  alarm  clocks 
read  clockwise,  the  station  clock  counter- 
clockwise; the  office  clock  with  24  hours 
instead  of  12,  and  our  wrist  watches  with 
markings  of  one  degree  for  each  of  the 
43,200  seconds  in  the  twelve  hours.  How 
in  the  name  of  microfarad  would  we  ever 
get    around? 


George  Balta,  4226  Todd  Ave.,  East 
Chicago,  111.,  browsed  around  the  news 
stands  until  he  found  RADIO  AGE, 
which  magazine  now  becomes  his  radio 
Bible  according  to  a  letter  received  re- 
cently. He  says:  "RADIO  AGE  with 
the  blueprint  section,  editorials  which 
every  radio  user  present  or  future  should 
read,  and  the  worth  while  articles  couched 
in  terms  anyone  with  average  intelligence 
can  understand,  gets  my  subscription 
enclosed  herewith."  That's  music  to 
our  ears.  The  list  of  stations  submitted 
also  shows  a  great  deal  of  patience  spent 
over  the  set  and  the  button  will  be  forth- 
coming as  a  result.  {Turn  the  i    ge) 


48 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


George  Morrow,  Salem,  Ohio,  known 
to  the  amateur  gane;  as  8DTN  (wonder 
if  it  means  Dial  Twisting  Nut?)  tells  us 
he  built  the  short  wave  set  following  our 
diagram  in  the  September  number  whch 
worked  so  well  he  had  to  let  us  know  of 
his  success.  With  the  set  he  copied  a 
flock  of  6th  District  amateurs  in  day- 
light; outside  of  the  U.  S.  he  logged  South 
Americans,  Mexicans,  Porto  Ricans, 
Bermudans,  Cubans,  Englishers,  French, 
New  Zealanders,  WAP  and  WNP  while 
at  Etah,  Greenland,  and  a  host  of  others. 
This  on  a  two  tube  set  with  a  50  foot 
vertical  antenna.  The  stations  above 
were  in  addition  to  about  200  other 
Canadians  and  Americans.  All  of  which 
we  would  say  speaks  eloquently  both  for 
the  perseverance  of  8DTN  and  the  sure- 
fire  dope   in   our  columns. 


From  the  West  Coast  comes  a  letter 
from  Ralph  E.  Riley,  1711  5th  St.,  Oak- 
land, Calif.,  who  hearkened  to  our  advice 
to  build  the  set  described  on  page  23  of 
the  February,  1925,  RADIO  AGE.  He 
says  the  results  obtained  are  nothing 
short  of  remarkable  and  thanks  RADIO 
AGE  for  the  competent  advice  rendered. 
He  says:  "you  surely  know  your  stuff — 
you'll  find  me  a  constant  booster."  Mr. 
Riley  made  a  few  changes  in  the  r.  f.  t. 
unit,  using  a  basket  wound,  the  second- 
ary turns  ranging  from  65  to  70,  and  with 
eight  to  twelve  turns  on  the  primary. 


Another  West  Coaster,  Harold  Bassett, 
216  North  Tower,  Centralia,  Washing- 
ton, writes  as  follows:  "Please  excuse 
my  apparent  boastfulness  but  I  am  proud 
of  the  operation  of  my  set.  I  have  several 
sets,  the  most  prominent  of  them  a  one 
tuber.  With  this  set  I  regularly  tune  in 
Eastern  stations  among  which  are  Cleve- 
land, Chicago,  Kansas  City,  Oklahoma 
City  and  Pittsburgh.  I  have  received 
Pittsburgh  with  no  aerial,  on  the  loud 
speaker.  All  the  before-mentioned  cities 
were  received  on  the  speaker.  Recently 
this  set  pulled  down  three  different  stations 
in  Chicago  in  one  evening.  With  an  Arm- 
strong regenerative  and  two  stages  of  am- 
plification many  more  Eastern  stations 
were  added  to  the  list,  including  Washing- 
ton, D.  C,  Buffalo,  Atlanta,  Schenectady 
and  PWX,  Havana.  Local  fans  with  5  and 
6tube  sets  equal  but  do  not  pass  this  for  dis- 
tance." Attaboy!  Looks  like  the  simple 
life  is  just  as  good  after  all,  at  least  in  the 
selection  of  the  reliable  circuits  for  maxi- 
mum   distance    and    constancy. 


John  D.  Zahn,  Canal  Winchester,  Ohio, 
also  sends  in  a  good  looking  list  of  sta- 
tions with  which  he  qualifies  for  the  em- 
blem of  the  fraternity. 


Robert  Sieglinger,  120  East  90th  St., 
Chicago,  111.,  also  is  enrolled  in  the  or- 
ganization after  submitting  a  list  of 
broadcasters  yanked  in  during  the  course 
of  an  evening.  Chicago  listeners  must 
have  good  sets  in  order  to  batter  down 
the  local  barrage  on  every  night  except 
Mondays. 


Ladies  and  gentlemen  of  the  DT's! 
Here  at  last  we  present  an  exclusive  picture 
of  the  greatest  malefactor  of  radio  than 
whom  there  is  no  peer.  It  is  the  cause  for 
more  cussing,  inquiring  into  a  set  with 
pliers,  changing  of  grid  leaks  and  the 
purchase  of  new  B  batteries  than  any  of 
the  other  agencies  of  science  with  which 
the  distance  hunter  is  accursed.  It  has 
potentialities  for  great  harm  and  yet  some 
good.  It  throws  a  twenty  inch  spark  with 
a  magnificent  brush  discharge,  the  voltage 
being  approximately  ten  million.  The 
wax  immersed  condenser  has  a  capacity 
of  24  quart  Leyden  jars. 

Seriously,  however,  the  photograph  shows 
a  Tesla-Oudin  coil  with  condenser,  designed 
by  the  Joseph  G.  Branch  Institute  of  Engi- 
neering, Chicago,  III.  The  picture  is 
furnished  by  M.  J .  Sahanel,  secretary  of 
the  Institute  who  sardonically  remarks 
that  this  apparatus  in  operation  destroys 
all  radio  reception  in  the  neighborhood  and 
opens  great  possibilities  for  use  in  this 
work.  With  it  most  beautiful  spectacular 
experiments  can  be  performed  and  in 
scientific  investigation  especially  in  radio 
work  is  of  much  value. 

We  have  not  quite  figured  out  how  we 
are  going  to  use  this  coil  in  our  laboratory 
work  but  we  might  use  it  in  connection 
with  the  extermination  of  the  incessant 
blooper  or  canary  hound  who  eternally 
pierces  the  night  with  his  dismal  shriek, 
the  mating  song  of  the  grid  calling  to  its 
plate. 


Oklahoma,  reports  a  broadcasting  station 
in  Buenos  Aires  in  addition  to  the  con- 
ventional dx  work  in  the  U.  S.  A.,  Canada 
and  Mexico.  Another  member  added 
to  the  DT  family. 


tandem  their  condensers  so  as  to  get 
single  control  of  two  tuned  r.  f.  stages. 
There  are  many  methods  of  balancing 
the  capacities  in  the  twin  units  and  the 
most  direct  and  simple  expedient  is  to 
buy  a  good  tandem  variable  condenser 
already  provided  with  equalizing  or 
balancing  verniers  consisting  of  a  midget 
condenser  alongside  the  main  capacities. 
However  there  are  many  who  have  a 
whole  shelf  full  of  old  condensers  and 
it  is  to  this  gentry  the  remarks  of  George 
H.  Hawley,  69  Walnut  Ave.,  Roxbury, 
Boston,  Mass.  are  dedicated.  Mr. 
Hawley  writes  as  follows: 

"The  radio  magazines  are  bringing 
to  the  experimenter  the  idea  of  less 
dials  by  means  of  gang  condensers. 
The  idea  is  good  but  most  fans  have  at 
present  a  very  nice  box  full  of  condensers 
which  they  would  like  to  press  into 
service.  Suggestions  have  appeared 
showing  how  to  join  the  singles  into  a 
tandem  condenser.  But  I  do  not  agree 
with  the  method  of  balancing  with  a 
smaller  condenser  shunted  across  the 
big  one  as  the  capacity  is  not  constant 
through  the  entire  dial  range,  but  drops 
from  the  maximum  amount  when  the 
plates  are  all  in  to  zero  when  the  plates 
are  all  out.  Thus  a  balancing  condenser 
with  its  capacity  set  would  not  be  in 
balance  over  the  entire  range.  It  would 
only  balance  for  the  wavelength  for  which 
it  was  balanced  and  would  be  out  for 
any  higher  wave,  thus  throwing  out  of 
tune  one  of  the  coils  and  perhaps  losing 
the  weak  signals  by  being  off  tune. 
The  better  way  to  balance  is  to  balance 
the  condensers  themselves,  which  is 
not  so  hard  as  it  seems  and  does  not 
require  laboratory  instruments  to  make 
a  very  good  job.  After  the  gang  is 
made  up,  being  certain  of  perfect  align- 
ment of  rotors  so  they  enter  at  same 
time,  mount  on  a  temporary  panel  and 
put  on  dial.  Now  tune  your  favorite 
set  to  a  distant  station  of  high  wave- 
length and  shunt  your  condenser  to  be 
tested  across  the  one  in  your  set.  Turn 
the  dial  on  your  set  to  about  10  and 
retune  the  set  using  one  of  the  gang  to 
be  tested.  Without  moving  the  instru- 
ments shift  the  connection  on  the  gang 
to  the  other  stator.  If  this  throws  the 
set  out  of  tune  go  to  your  dial  on  set 
and  move  slowly  backwards  and  for- 
wards from  the  mark  10  and  you  will 
find  the  condenser  which  has  the  greatest 
capacity.  The  remedy  is  very  simple 
and  will  balance  through  the  entire 
range.  Remove  the  end  plate  from  the 
offending  member  and  take  off  one 
stator  plate.  With  a  pair  of  dividers 
scribe  a  circle  about  the  shaft  clearance 
portion  (as  shown  by  dotted  lines  in 
Fig.  3)  so  as  to  remove  about  an  eighth 
or  a  quarter  of  an  inch  of  the  plate, 
then  replace  for  test.  It  will  probably 
take  several  trips  to  balance  but  you 
make  a  real  job  of  the  matter,  and  not 
a  makeshift  with  an  extra  control.  A 
fine  jeweler's  saw  will  remove  the  part 
you   have   marked   very   nicely." 


J.    P.    Morrison,    Jr.,    amateur    radio 
5BT,   at    1711   South    Peoria  St.,   Tulsa, 


Perhaps   some   members   of   the   radio 
family   are   busily  engaged   in   trying  to 


We  often  wonder  how  long  it  will 
take  the  radio  world  to  realize  that 
sharpness  of  the  signal  (though  weak) 
in  the  secondaries  of  tuned  r.  f.   stages 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


49 


Fig.  2.  This  is  the  form  of  regenerative  set  used  by  Carl  Streiferd,  South  Braintree, 
Mass.  It  seems  to  have  plenty  of  inductances,  whose  functions  are  explained  in  the  text. 
The  circuit  is  conventional  although  the  arrangement  of  inductances  departs  from  the 
well  known  methods.  The  32  turn  and  36  turn  windings  are  rotors,  the  latter  governing 
regeneration.    Selectivity  may  be  altered  by  tapping  the  primary  winding. 


(which  can  later  be  amplified  at  will) 
is  preferable  to  a  strong,  broad  signal. 
The  reason  for  the  above  remark  is  a 
recent  test  of  two  types  of  r.  f.  tuning 
units  in  actual  operation.  With  one 
there  was  a  great  deal  of  volume  but  the 
signal  mushed  over  a  section  of  the  dial 
corresponding  to  about  seven  to  ten 
degrees  either  way  from  a  given  point. 
With  the  other  units  in  place,  no  other 
changes  having  been  made,  the  same 
signal  was  sharp  as  a  briar,  and  could 
be  tuned  out  within  two  divisions  on 
the  scale  either  side  of  a  given  point. 
The  sharp  signal  was  then  properly 
amplified  and  we  attained  the  desired 
volume  with  excellent  selectivity.  The 
other  unit  whose  signals  were  broad 
was  hooked  up  to  the  amplifier  and 
wonderful  volume  resulted,  but  ye  gods 
selectivity  had  departed  via  the  back 
door  and  Charlie  Erbstein's  voice  at  the 
new  Liberty  station  WLIB  (formerly 
WTAS)  smeared  itself  all  over  the  en- 
trancing notes  of  the  Little  Symphony 
at  KDKA.  The  separation  in  wave 
length  at  this  band  is  about  six  meters. 
The  good  unit  makes  the  grade;  the  poor 
one  falls  down.  The  moral  of  this  tale  is 
that  all  tuned  r.  f.  units  should  be  good. 
If  necessary  a  definite  standard  of  ex- 
cellence should  be  established,  perhaps  by 
the  Bureau  of  Standards,  and  then  all 
manufacturers  should  try  to  beat  the 
mark    if     possible     instead     of     merely 


The  circuit  above  is  a  low  power  telephone  transmitter,  for  which  it  will  be  necessary  to  have  a  government  license.  It  is  contributed 
by  Paul  M.  Hayes  of  Pasadena,  Calif.  The  constants  are  shown  in  the  diagram  and  in  the  text  in  this  department.  B  battery' plate 
potential  will  be  ok  for  short  range  work.  A  flashlight  may  be  used  instead  of  the  ammeter  in  series  with  the  antenna.  The  modulation 
transformer  is  20  to  1  ratio.    The  A  battery  lights  the  tube  and  also  furnishes  current  for  the  microphone, 


50 


RADIO  AGE /or  December,  1925 


dumpingon  the  market  just  one  more  tuned 
r.  f.  unit.  But  We  are  inclined  to  optim- 
ism and  are  at  least  thankful  there  are  some 
manufacturers    turning  out  good    parts. 


Frank  Wiles,  110  North  9th  St.,  Lamar, 
Colo.,  uses  a  one  tube  Reinartz  in  logging 
his  stations  and  reports  a  list  that  easily 
entiles  him  to  the  coveted  button.  The 
list  takes  in  all  directions  including 
Canada  and  Mexico. 


Leon  C.  O'Connor,  47  Brownell  Ave., 
Hartford,  Conn.,  using  a  super,  dry  cell 
tubes  and  loop,  sends  in  a  list  of  stations 
the  nearest  one  mile  and  the  farthest 
2050  miles,  which  we  would  say  is  pretty 
good  work  even  for  a  super.  Welcome 
into  the  family. 


Carl  Streiferd,  Braintree,  Mass.,  uses 
the  circuit  shown  in  Fig.  2,  using  199 
tubes,  45  volts  B  battery,  and  no  C  battery. 
He  says  his  results  are  ahead  of 
other  sets  using  a  different  hookup.  The 
circuit  is  conventional  but  the  number 
of  inductances  is  probably  in  excess  of 
the  number  required  to  get  good  signals. 
But  if  the  fans  did  not  have  different  ideas 
on  the  game  we  would  all  be  using  the 
single  circuit  or  a  crystal.  In  the  circuit 
shown  in  Fig.  2  regeneration  is  controlled 
by  the  36  turn  rotor.  Rotor  No.  1,  which 
is  the  32  turn  rotor,  is  not  varied  much 
after  once  finding  the  correct  setting. 
The  two  16  turn  windings  are  fixed,  the 
32  turn  winding  being  on  a  rotor  as  is  the 
36  turn  winding.  The  50  turn  secondary 
is  fixed  as  is  the  10  turn  primary.  The 
selectivity  may  be  altered  by  tapping  the 
primary  winding.  The  coils  are  wound, 
a  la  Lorenz,  using  No.  22DCC  wire.  The 
antenna  10  turns,  secondary  50  turns  and 
tickler  36  turns  are  on  one  line,  the  latter 
being  a  rotor  at  the  end  of  the  50  turn 
secondary.  The  two  16  turn  and  one  32 
turn  windings  are  on  another  tube,  the 
32  turn  winding  also  being  on  a  rotor. 
The  variable  across  the  secondary  is  a 
.0005  mfd  condenser.  In  your  spare 
moments  you  might  rig  it  up  and  try  it. 


Readers  who  may  be  interested  in  a 
cheap,  low-power  telephone  transmitter 
(for  which  of  course  you  will  have  to 
get  a  government  license)  will  find  this 
detailed  in  Fig.  4,  the  contribution  of 
Paul  M.  Hayes,  Pasadena,  Calif.  The 
primary  of  the  oscillation  transformer 
consists  of  18  turns  of  wire,  using  antenna 
and  counterpoise,  a  zero  to  two  and  a 
half  ampere  meter  in  series  with  the 
antenna.  The  secondary  is  22  turns, 
with  grid  at  one  end,  filament  about  the 
center  and  B  supply  line  at  the  other 
end,  with  a  .0005  variable  spanning  the 
extremities   of   the   coil.      A    modulation 


The  Magazine  of  the  Hour 

transformer,  ratio  20  to  1  is  used,  ener- 
gized by  the  microphone  and  A  battery, 
the  latter  also  serving  to  light  the  trans- 
mitter tube.  Sixty  to  eighty  volts  B 
battery  will  run  the  set,  using  a  201-A 
or  the  like.  The  ammeter  in  the  an- 
tenna circuit  may  be  replaced  by  a  small 
flashlight  bulb  which  will  glow  when 
resonance  is  established.  Be  sure  to  get 
a  government  license  before  trying  the 
set  out  on  the  air.  The  schematic  is 
shown  in  Fig.  4. 


Scheme  outlined  by  Mr.  Hawley  is  shown 
in  Fig.  3  above.  The  end  stator  plate  is  re- 
moved from  the  gang  that  is  high  in  capacity, 
and  trimmed  down  in  accordance  with  the 
dotted  line.  Probably  an  eighth  of  an  inch 
should  be  taken  off  at  a  time  unti  Ithe  ca- 
pacity on  a  given  signal  is  equal  to  that  of 
its  mate  in  the  tandem  arrangement.  A 
jeweler's  saw  will  do  the  work  nicely.  How- 
ever it  is  more  or  less  of  a  cut  and  try  method. 


It  was  originally  intended  to  publish 
the  circuit  shown  in  Fig.  4  in  the  Novem- 
ber number  but  lack  of  space  at  the 
last  moment  prevented.  However  the 
contribution  of  Mr.  Hayes  is  included 
in  the  department  this  month. 

Perhaps  many  radio  fans  would  like 
to  get  into  the  transmitting  game  but 
are  prevented  through  their  inability 
to  master  the  Continental  code.  Know- 
ledge of  the  code  at  a  speed  of  about 
ten  words  per  minute  and  ability  to  recog- 
nize the  SOS  signal  sent  at  that  rate  of 
speed,  together  with  a  transmitter  that 
will  pass  the  government  inspector's 
eagle  eye  is  about  all  that  is  required 
in  the  way  of  securing  a  license.  But  the 
transmitting  game  certainly  takes  a  lot 
of  your  time  and  money;  be  prepared  to 
weep  copiously  every  time  you  burn 
out  a  five  watt  bottle  or  when  you  short 
an  8  volt  scale  voltmeter  across  220  volts. 
But  there  is  a  kick  in  it  after  all  and  per- 
haps it  is  the  kick  you  have  been  seeking. 


George  A.  Winkle,  223  Old  50th  St., 
Birmingham,  Ala.,  tells  us  of  the  success 
he  has  with  the  conventional  regenerative 
circuit,  adapted  to  three  tubes  for  the 
chap  who  is  not  able  to  stand  the  ex- 
pense of  a  six  or  ten  tube  set. 


End  Your  Radio  Troubles  for  30c  in  Stamps 

We  have  laid  aside  a  limited  number  of  back  issues  of  RADIO  AGE  for  your  use.  Below  are  listed  hookups  to  be 
found  in  these  volumes.  Select  the  ones  you  want  and  enclose  30c  in  stamps  for  each  desired.  The  supply  is 
limited,  so  enrich  your  store  of  radio  knowledge  by  laying  in  an  ample  stock  of  copies  NOW! 


January.  1924 

—Tuning  Out  Interference — Wave  Traps — Eliminators 

—Filters 

— A  Junior  Super-Heterodyne. 

— Push-Pull  Amplifier. 

— Rosenbloom  Circuit. 

March,  1924 

— An  Eight-Tube  Super-He t-erodyne. 

— A  simple,  low  loss  tuner. 

— A  Tuned  Radio  Frequency  Amplifier. 

— Simple  Reflex  Set. 

April.  1924 

— An  Efficient  Super-Heterodyne  (fully  illustrated). 

—A  Ten  Dollar  Receiver. 

— Anti-Body  Capacity  Hookups. 

— Reflexing  the  Three-Circuit  Tuner. 

— Index  and  first  two  installments  of  Radio  Age  Data  Sheets. 

May,  1924 

— Construction  of  a  Simple  Portable  Set. 

— Radio  Panels. 

—Third  Installment  of  Radio  Age  Data  Sheets. 

June,  1924 

— Important  Factors  in  Constructing  a  Super-Heterodyne. 

— 'A  Universal  Amplifier. 

— A  Sure  Fire  Reflex  Set. 

— Adding  Radio  and  Audio  to  Baby  Heterodyne. 

— Radio  Age  Data  Sheets. 

July,  1924 

— A  Portable  Tuned  Impedance  Reflex. 

— Operating  Detector  Tube  by  Grid  Bias. 

—A  Three-Tube  Wizard  Circuit. 

— Data  Sheets. 

August,  1924 

— Breaking  Into  Radio  Without  a  Diagram. 

— The  English  4-Element  Tube. 

— Filtered  Heterodyne  Audio  Stages. 

— An  Audio  Amplifier  Without  an  "A"  Battery. 

— Data  Sheets. 

September,  1924 

— How  Careful  Mounting  Will  Improve  Reception. 

— One  Tuning  Control  for  Hair's  Breadth  Selectivity. 

— Four  Pages  of  Real  Blueprints  of  a  New  Baby  Heterodyne 

and   an   Aperiodic   Variometer   Set. 
— Data  Sheets. 


October,  1924 

— An  Easily  Made  Super-Het. 
— Two  Radio  and  Two  Audio  for  Clear  Tone. 
— A  Simple  Regenerative  Set. 
— The  Ultradyne  for  Real  DX. 

—Real  Blueprints  of  a  3-Tub©  Neutrodyne  and  a  Midget 
Reflex  Set. 

November,  1924 

— Blueprints  of  a  Single  Tube  Loop  Set  and  a  Capacity  Feed- 
back Receiver. 

— A  3-Tube  Low  Loss  Regenerator. 

— Mastering  the  3-Circuit  Tuner. 

December,  1924 

— Blueprints  of  a  New  8-Tube  Super-Heterodyne. 

— How  to  Make  a  Receiver  that  Minimizes  Static. 

— A  Trans- Atlantic  DX  Receiver. 

— How  to  Make  a  Home  Made  Battery  Charger  and  a  Loud 
Speaker  at  a  Small  Cost. 

January,  1925 

— A  Reflexed  Neutrodyne. 

—A  Six  Tube  Super-Het. 

— An  Efficient  Portable  Set. 

— A  Tuned  Plate  Regenerator. 

— Making  a  Stat  ion- Finder. 

February,  I92S 

— A  Sure  Shot  Super-Het. 

— A  Three  Circuit  Regenerator. 

— A  Real,  Low  Loss  Set. 

— Blueprints  of  a  3-tube  Reflex. 

March,  1925 

— A  Permanent  Sup-Het. 

—A  5-Tube  R.  F.  Receiver. 

— How  to  Wind  Low  Loss  Coils. 

— A  Short  Wave  Receiver. 

— Blueprints  of  a  Two-Tube  Ultra  Audion  and  a  Regenerative 
Reflex. 

April,  1925 

—A  3-Tube  Portable  Set. 

— "B"  Voltage  from  the  A.  C.  Socket. 

— An  Amplifier  for  the  3-Circuit  Tuner 

—Blueprints  of  a  Five-Tube  Radio  Frequency  Receiver 


May,  1925 

— A  "Quiet"  Regenerator. 

— A  Power  Supply  Receiver. 

— How  to  Make  a  Tube-Tester. 

— A  Unique  Suoer-Het  and  an  Improved  Reinsrts. 

— A  Six  Tube  Portable  Receiver  Illustrated  with  Blueprints. 

June,  1925 

— Reducing  Static  Disturbances. 

— A  Seven-Tube  Super-Heterodyne. 

— The  Double  Grid  Tube  in  Ordinary  Seta. 

— ■Browning-Drake  Receiver. 

— Overcoming  Oscillations  in  the  Roberta  Receiver. 

— An  Ideal  Set  in  Practical  Form. 

— Soldering  Secrets. 

July,  1925 

— Learning  Tube  Characteristics. 

— How  Much  Coupling? 

— The  Six-Tube  Super-Autodyne. 

— A  Simplified  Portable  Super-Set. 

— 'Blueprints  of  Conventional  Radio. 

— Symbols  and  Crystal  Detector  Circuit. 

August,  1925—  50c  per  copy 

— How  to  Attain  Smooth  Tuning. 

— Alternating  Current  Tubes. 

— Deciding  on  a  Portable  Super — 

— And  a  big  60-page  blueprint  section,  in  which  Is  contained 
blueprints  of  all  the  basic  circuits  from  which  all  radio 
hookups  have  been  developed  since  the  birth  of  Radio. 

September,  1925 

— Thirty-one  ways  to  prevent  self-oscillations. 

— Tuning  efficiency  with  two  controls. 

— Ideal  Audio  Amplifier  Circuits. 

— Blueprint  section. 

October.  1925 

— Auto-Transformer  Coupling. 

— Some  Facts  about  Quality. 

— An  Improved  Slide- Wire  Bridge. 

— Blueprints  of  Circuits  Using  Single  and  Dual  Controls. 

November,  1925 

— A  Super-Het  without  I.  F.  Stages. 

— How  to  Make  a  Windless,  Pipeless  Organ 

— A  New  Low  Loss  "Special,  Four," 

— How  to  make  a  Low  Wave  Transmitter 

—Blueprints  of  Making  R.  F.  Stafes. 


Radio  Age,  Inc.,  500  N.  Dearborn  St,  Chicago 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


51 


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9he  World's  Greatest 
^adio  Story  - 


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Ward's  New  Radio 
Catalogue  is  Now  Ready 


-fQ 


Are  you  interested  in  seeing  what 
is  new  in  Radio —  what  is  best 
and  what  has  been  approved? 

And  do  you  wish  to  know  the 
lowest  prices  on  tested  sets,  prices 
made  without  the  usual  "Radio 
profits?" 

This  Catalogue  is  a 
Complete  Guide  to  Radio 

Ward's  is  headquarters  for  Radio, 
with  probably  the  largest  retail 
radio  department  in  the  whole 
world. 

This  new  52  page  Radio  Catalogue 
shows  everything  in  parts,  batteries, 
cabinets,  contains  a  list  of  stations,  a 
radio  log  for  recording  stations.  It 
shows  the  best  of  the  new  sets.  One 
tube   sets   that   give  amazing  results. 


Five  tube  sets  with  a  single  dial  to  turn. 
Think  of  tuning  in  one  station  after 
another  by  turning  a  single  dial! 

Every  price  quoted  means  a  big  sav- 
ing to  you.  Everything  offered  is  tested 
by  our  own  Radio  Experts.  In  fact, 
the  best  experts  compiled  this  Cata- 
logue for  you. 

Write  for  this  52  Page  Book.  It  is 
yours  free. 

Our  53  year  old  Policy 

For  53  years  we  have  sold  only  quality 
merchandise  under  a  Golden  Rule 
Policy.  You  can  rely  absolutely  upon 
the  quality  of  everything  shown  in  this 
Radio  Catalogue. 


18-R 

r-      St.  Paul 


MontgometjTWard  &Ca 

The  Oldest  Mail  Order  House  is  Today  the  Most  Progressive 

Baltimore  Chicago   Kansas  City  St.  Paul  Portland,  Ore.   Oakland,  Calif.   Ft.  Worth 


To  Montgomery  Ward  &  Co.,  Dept. 

Baltimore      Chicago      Kansas  City 
Portland,  Ore.      Oakland,  Calif.      Fort  Worth 

(Mail  this  coupon  to  our  house  nearest  you.) 
Please  mail  my  free  copy  of  Montgomery  Ward's 
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52  RADIO  AGE  for  December,  1925 

WITH 


The  Magazine  of  the  Hour 

URERS 


Dealers  Attend  De  Forest 
"Pep"  Meeting 

Over  three  hundred  metropolitan  dealers 
attended  the  "pep"  dinner,  given  by  the 
De  Forest  Radio  Company  and  its  five 
metropolitan  distributors  at  the  Waldorf- 
Astoria  Hotel  on  October  2nd. 

The  dinner  was  opened  by  an  address 
of  welcome  by  H.  L.  Lanphear,  General 
Manager  of  the  De  Forest  Company,  who 
stressed  the  value  of  a  set  sold  one 
hundred  percent,  and  pointed  out  that 
Radio  was  witnessing  the  same  growth  as 
other  young  industries,  namely  the 
public  placed  their  faith  in  a  dealer  who 
not  merely  "sold"  them,  but  who  gave 
service. 

Samuel  H.  Darby,  genera!  counsel  for 
the  De  Forest  Company,  urged  the  dealers 
to  encourage  the  ideas  of  amateurs  in 
radio.  Very  often  a  man  comes  into  a 
shop  and  falls  into  conversation  with  a 
salesman  over  the  counter.  He  may  have 
an  idea  toward  improving  a  set  that  is 
really  fundamental,  and  in  which  the 
manufacturer  would  be  interested,  but 
these  two  seldom  get  together.  The 
dealer  is  in  a  personal  relationship  to 
both.  The  De  Forest  Company  has  been 
very  gracious  to  inventors  all  during  its 
history,  and  very  often  a  man  with  a  good 
idea  has  been  helped  to  find  a  market.  So 
long  as  dealers  can  keep  alive  a  healthy 
curiosity  about  radio  their  sales  will  be 
big.  They  must  do  their  part  in  keeping 
the  interest  of  the  man  who  likes  to 
tinker  and  experiment. 

Robert  E.  Rinehart,  Vice  President  of 
the  William  H.  Rankin  Company,  in 
charge  of  advertising  and  publicity,  spoke 
on  the  good  luck  of  the  dealer  in  radio, 
for  this  is  one  industry  which  needs  no 
excuse  for  its  being.  Mr.  Rinehart  laid 
emphasis  on  the  fact  that  crowds  visited 
the  dealer  just  as  a  matter  of  information. 
Because  of  the  fact  that  radio  is  in  its 
infancy,  the  dealer  is  looked  on  as  a  sort 
of  bureau  of  public  information,  as  a  refer- 
ence handbook.  The  public  wants  to  know 
what  the  manufacturer  is  doing,  and 
he  comes  to  the  place  where  he  knows 
this  news  can  be  obtained. 


Eby  Has  Cushion  Socket 
For  UX  Tubes 

With  the  advent  of  the  new  UX  tubes 
comes  the  development  of  sockets  that 
are  in  keeping  with  their  efficiency. 

The  H.  H.  Eby  Mfg.  Company  of 
Philadelphia  has  just  announced  a  new 
type  of  cushion  socket  that  insures  a 
positive  contact  at  all  times. 

This  socket  grips  each  of  the  four  tube 
prongs  their  entire  length  with  three- 
jawed  Phosphor  Bronze  spring  clips. 
Each  spring  clip  is  securely  riveted  to 
the  Bakelite  base  assuring  a  good  electrical 
joint  and  permitting  the  tube  to  "float" 
when  in  service.  This  shock-absorbing 
feature  eliminates  microphonic  noises 
and  is  a  guarantee  against  tube' damage. 


Fixed  Resistors  That  Do  Not 
Deteriorate 

The  Allen-Bradley  Company  of  Mil- 
waukee, have  perfected  a  fixed  resistor  of 
the  molded  composition  type,  which  is 
impervious  to  moisture  and  atmospheric 
changes,  and  does  not  deteriorate  with 
age  or  service.  Silver  plated  contacts 
on  each  end  of  the  Bradleyunit,  as  this  re- 
sistor is  called, are 
molded  in  place. 
The  Bradleyunit 
does  not  rely  up- 
on hermetic  seal- 
ing to  avoid  de- 
terioration. The 
silver  plated  con- 
tacts are  pro- 
vided with  holes 
for  soldering,  or 
they  may  be  used 
in  the  standard 
mounting  clip. 

Bradley -unit - 
Amplifier  Resist- 
ors are  six  Brad- 
leyunits  of  the 
correct  rating  for  resistance-coupled  am- 
plifiers. Since  Bradleyunit  resistors  do 
not  deteriorate,  and  are  guaranteed  to  be 
within  5  per  cent  of  the  rated  resist- 
ance, they  can  be  used  with  the  most 
satisfactory  results  possible,  either  in 
building  resistance-coupled  amplifiers,  or 
replacing  resistors  not  of  the  molded 
type,  in  amplifiers  in  service. 


Bosch  Builds  Wood  Cone 
Reproducer 

An  entirely  new  trend  in  radio  repro- 
duction is  advanced  by  the  American 
Bosch  Magneto  Corporation  in  its  Ara- 
botone  Reproducerwith  a  wooden  conoid. 
The  entire  cone  diaphragm  is  wood  in- 
stead of  the  conventional  paper. 

Unusual  mellowness  is  claimed  for  this 
feature  as  wood  in  musical  instruments 
has  always  been  looked  to  for  pleasing 
tone  qualities.  This  wood  diaphragm  is 
18  inches  across  which  contributes  to 
the  full  reproduction  of  the  bass  tones  so 
often  lost  in  radio  reproduction. 

The  wood  conoid  is  finished  in  mahog- 
any with  a  parquetry  inlay  touch.  The 
base  and  metal  parts  are  finished  in  art 
bronze. 


Shortage  Over 

The  temporary  shortage  which  existed 
recently  on  MU  6  tubes,  power  type, 
made  by  the  Daven  Radio  Corporation 
at  Newark,  N.  J.,  has  been  relieved, 
according  to  advices  from  their  factory. 
Both  the  MU20  which  is  the  amplifier 
type  for  resistance  coupled  sets  and  the 
MU6  which  is  a  power  tube  for  the  last 
stage,  are  in  full  production. 


Furnell  Taper  Coil  Condensers 

The  Furnell  Taper  Coil  Condenser 
introduces  the  first  "new  idea"  principle 
offered  in  condenser  design.  Up  to  its 
advent,  practically  all  variable  condensers 
were  of  the  same  general  type. 

Heretofore,  condensers  have  been  made 
up  of  two  series  of  projecting  plates,  that 
intermeshed  by  the  movement  of  a 
rotating  shaft,  or  rotor.  The  limitations, 
as  well  as  the  deficiencies  of  this  old  type 
condenser,  have  long  been  recognized  by 
the  professional. 

The  Furnell  Taper  Coil  principle  is  such 
an  advance  forward  in  condenser  effi- 
ciency, as  to  distinguish  it  as  the  new 
standard  of  condenser  design. 

Due  to  their  improved  principle — their 
simplicity — their  ruggedness — their  per- 
manent alignment  under  all  conditions — 
Furnell  Taper  Coil  Condensers  afford  a 
smoothness  of  action,  an  accuracy,  and 
a  sharpness  of  tuning. 


Westinghouse  Intl.  Announces 
New  Appointments 

C.  _V.  Allen,  formerly  Manager  of  the 
Westinghouse  Electric  International  Com- 
pany in  Mexico,  has  been  elected  Assis- 
tant Treasurer  of  the  Company,  with 
headquarters  in  New  York  City  as  general 
assistant  to  H.  A.  Carmichael,  Treasurer. 
The  appointment  was  effective  October 
15,  according  to  an  announcement  from 
the  executive  offices  of  the  Company  in 
New  York.  Clayton  T.  Rogers,  Sales 
Manager  for  the  Mexican  Branch,  is  Act- 
ing Manager  succeeding  Mr.  Allen. 

Mr.  Allen  has  been  with  the  Westing- 
house organization  for  thirty  years. 
Before  being  made  Manager  of  the 
Mexican  Branch  of  the  International 
Company,  he  had  acted  as  Westinghouse 
Special  Agent  in  Mexico.  He  assumed 
the  Managership  of  the  branch  division 
at  the  time  of  its  organization  in  1921. 

Mr.  Allen  is  a  graduate  of  the  Massachu- 
setts Institute  of  Technology,  and  began 
his  career  with  the  Westinghouse  Com- 
pany as  a  graduate  student,  working  in 
both  the  East  Pittsburgh  and  New 
York  Offices  before  entering  the  foreign 
field. 


Adds  Floor  Space 

To  keep  pace  with  its  expansion  pro- 
gram the  R.  E.  Thompson  Manufacturing 
Company,  radio  manufacturers,  has  ac- 
quired by  lease  an  additional  two  floors 
in  a  separate  building  in  Jersey  City, 
where  its  main  plant  is  located. 

Including  the  two  floors  just  leased,  at 
314  Claremont  Avenue,  and  four  entire 
floors  recently  leased  in  the  103  Greene 
Street,  Jersey  City  Building,  the  company 
has  now  aided  approximately  25,000 
square  feet  of  leased  floor  space  to  the 
plant  facilities  it  owns  at  66  York  Street, 
Jersey  City. 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


53 


Equal  Impedance  Secret 
of  New  Radio  Sets 

Simultaneously  with  the  introduction 
of  two  revolutionary  types  of  talking 
machines  embodying  newly  discovered 
principles  of  sound  reproduction,  the 
Victor  Talking  Machine  Company,  of 
Camden,  N.  J.,  announces  that  models 
of  both  lines  of  instruments  will  be 
produced  in  combination  with  radio 
receiving  sets  ranging  from  five  to  eight 
tubes.  The  new  Orthophonic  Victrola, 
and  the  electrical  amplifying  talking 
machine  to  be  known  as  the  Electrola, 
are  to  be  put  on  the  market  with  built-in 
radio  sets  of  the  very  latest  types  (Radi- 
olas  25  and  28)  announced  by  the  Radio 
Corporation    of    America. 

At  the  same  time,  the  Victor  Com- 
pany is  announcing  a  clock  type  loud 
speaker,  based  on  distinctly  new  prin- 
ciples of  sound  reproduction,  which 
employs  the  double  balanced  diaphragm 
principle,  and  a  pleated  parchment  sound 
radiating  surface.  The  electro-magnetic 
unit  energizes  the  entire  surface  of  the 
diaphragm,  giving  loud,  undistorted 
reproduction  when  used  in  connection 
with  any  good  audio-frequency  am- 
plifier. 

It  is  the  mechanical  application  of 
the  principle  of  matched  impedance 
which  has  made  possible  the  Ortho- 
phonic  talking  machine  used  in  all  the 
new  line  of'  combination  instruments. 
Accoustical  engineers  state  the  Ortho- 
phonic  talking  machine,  by  reason  of 
the  matching  of  all  impedances,  has 
made  possible  the  mechanical  reproduc- 
tion of  sound  from  a  talking  machine 
record  which  is  infinitely  more  efficient 
than  any  previous  accomplishment  in 
this   industry. 


Leads  are  Separated   in   New 
De  Forest  "H"  Tube 

A  new  transmitting  tube,  in  design  the 
most  radical  departure  from  any  tube 
ever  placed  on  the  market,  is  the  latest 
achievement  of  the  De  Forest  Engineer- 
ing laboratories. 

This  makes  possible  the  use  of  extreme- 
ly high  voltages  with  no  chance  of  flash 
over.  Under  this  plan  the  tube's  efficiency 
is  not  only  increased,  but  the  danger  of 
breakdown  or  burn-out  is  reduced. 

In  construction  the  "H"  tube  differs 
from  the  ordinary  transmitting  tube  by 
having  its  leads  placed  like  the  four 
points  of  a  cross,  one  out  from  either 
side, — and  one  top  and  bottom. 


Tube   Vitalizer   Put   Out 
By  Hemco 

The  Hemco  Radio  Tube  Vitalizer  has 
been  placed  on  the  market  recently  by 
George    Richards   &   Co.,   of   Chicago. 

This  device  brings  any  tube,  new  or 
old,  to  maximum  operating  efficiency 
by  application  of  the  rethoriating  prin- 
ciple. The  201A  and  UV199  tubes, 
which  comprise  practically  all  the  tubes 
in  radio  receivers  today,  owe  their  suc- 
cess largely  to  the  tungsten-thorium 
alloy  of  which  their  filaments  are  made. 
They  are  excellent  detectors,  and  un- 
excelled as  amplifiers,  and  use  less  bat- 
tery current  than  any  other  type  of  tube. 

The  Hemco  Tube  Vitalizer  is  built  to 
operate  on  either  A.  C.  or  D.  C.  110  volt 
circuit,  so  it  can  be  attached  directly 
to  the  electric  light  circuit. 

Test  Handles  Fill  Need 

In  Radio  Experimenting 

A  set  of  test  handles  for  use  in  cad- 
mium, voltage,  polarity,  leaking  cells, 
meter  leads  and  many  other  tests  which 
will  suggest  themselves  to  the  radio  ex- 
perimenter, is  announced  by  the  Uni- 
versal Test  Equipment   Co. 

Among  the  radio  uses  of  the  handles, 
one  of  which  is  fitted  with  a  cadmium 
point,  are  the  following:  Testing  opens, 
shorts,  grounds,  condenser  tests,  polarity 
tests  and  resistance  tests.  The  points 
are  made  of  a  special  alloy  to  prevent 
breaking,  bending  or  corrosion. 


I 


In  construction,  the  new  "H"  follows 
the  general  design  of  the  Singer  tube. 
The  filament  operates  on  Tungsten  emis- 
sion, drawing  approximately  2.3  amperes 
at  10  volts.  The  grid  and  plates  are  of 
the  best  quality  material  that  the  Engi- 
neering Department  of  the  De  Forest 
Radio  Company,  pioneers  in  tube  manu- 
facture— have  been  able  to  find. 

The  tube  has  a  normal  output  of  20 
watts  at  a  plate  voltage  of  approximately 
700  volts,  but  due  to  the  unique  features 
in  its  design,  3000  volts  may  be  applied 
to  the  plate  without  causing  any  break- 
down or  in  any  way  shortening  the  life 
of  the  tube.  The  application  of  high 
plate  voltages  naturally  increases  the 
output  of  the  tube  and  it  has  been  found 
that  with  2000  volts  on  the  plate,  the 
output  varies  between  150  and  200 
watts,  depending  entirely  on  the  circuit 
and  to  a  large  extent  upon  the  necessary 
"C"  bias  which  is  used.  The  maximum 
safe  plate  dissipation  is  approximately 
170  watts.  With -1200  volts  in  the  plate 
no  "C"  battery  is  necessary. 


National    Carbon   Has 
New  Battery 

The  National  Carbon  Company  an- 
nounces a  new  Eveready  "B"  battery 
to  be  known  as  No.  779.  This  is  designed 
particularly  to  fit  the  battery  compart- 
ments of  certain  types  of  Operadio  and 
DeForest  receivers.  '  The  voltage  is 
22  3^    and    dimensions    4J^x3^x7^|. 

This  battery  is  added  to  the  Eveready 
line  in  accordance  with  its  established 
policy  of  meeting  every  existing  radio 
battery  need.  The  new  battery  permits 
the  use  of  the  largest  size  cells  possible 
in  the  battery  compartments  of  the  sets 
referred  to,  resulting  in  the  greatest 
economy  permitted  by  the  space  avail- 
able for  power  supply. 

"Bull  Dog"  Socket  Made 
By  Camfield 

Another  quality  product  recently 
brought  out  by  the  Camfield  Radio 
Manufacturing  Company  is  the  Type  11 
Bull  Dog  Grip  Socket.  This  socket  is 
designed  to  accommodate  three  different 
types  of  tube  bases.  Tubes  having  the 
Navy  standard  base,  the  new  X  Dry 
Storage  Battery  base,  or  the  new  X  Dry 
battery  base,  are  all  interchangeable  in 
this  socket  without  the  use  of  an  adaptor. 

The  heavy  phosphor  bronze  contact 
springs  grip  the  prongs  on  all  sides 
insuring  absolutely  perfect  contact,  elim- 
inating one  of  the  greatest  troubles 
encountered  in  set  operations  in  the  past. 

Variances    in  "B" 
Batteries 

Since  the  first  set  was  rigged  up  in  the 
cellar,  amateurs  and  engineers  have 
spent  years  in  developing  that  most 
important  source  of  local  energy,  the 
plate  battery.  Government  investigation 
has  revealed  the  fact  that  there  is  a  very 
wide  variance  in  the  standard  B  battery. 
Also,  that  the  results  obtained  from  any 
make  receiver  depends  first,  of  course, 
on  the  make  of  battery;  and  second,  on 
the  length  of  time  which  elapses  between 
its  assembly  at  the  factory  and  its 
installation  in  the  home. 

F.  M.  Ronsenfeld,  who  is  the  president 
of  the  Diamond  Electric  Specialties 
Company,  in  a  recent  interview,  declared 
that  his  firm's  policy  was  to  get  batteries 
to  the  purchaser  with  a  minimum  loss  of 
time  and  to  make  this  possible,  shipments 
are  sent  directly  to  the  dealer.  The 
company  keeps  in  very  close  touch  with 
their  dealers  and  batteries  are  not  allowed 
to  lose  energy  on  jobber's  shelves.  This 
procedure,  they  feel,  is  the  only  one  that 
is  fair  to  the  customer  who  is  anxious  to 
get  the  best  out  of  his  receiver. 

The  "Accuratune  Junior" 

An  Accuratune  Junior  has  iust  been 
announced  for  the  radio  fans  and  the 
trade  by  the  Mydar  Radio  Co.,  Newark, 
N.  J.  It  is  moulded  entirely  of  bakelite 
with  clearly  defined  graduations.  It  is 
beautifully  made  and  substantial.  The 
same  important  features  are  incorporated 
in  it  as  used  in  the  regular  Accuratune. 
Coarse  or  fine  tuning  is  furnished  through 
a  double  worm  drive.  The  dial  is  grad- 
uated either  zero  to  one  hundred  or  the 
reverse.  Its  diameter  is  four  inches.  It 
is  also  furnished  in  mahoganite  finish. 
This  is  a  new  addition  to  a  line  of  verniers 
and  dials  which  have  long  been  familiar  to 
readers  of  the  advertising  pages  of  Radio 
Age  and  should  be  of  interest  to  those 
desiring  a  medium  priced  vernier. 


54 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


Build  the  Set  That 
Holds  4  World's  Records 


The  receiver  that  brought  in  sta- 
tions 6,000  to  8,000  miles  distant 
with  loud  speaker  volume  night 
after  night. 

Holds  World's  Records  For 

(1)  Longest  distance  ever  received  on  a 
loop  aerial — 8,375   miles 

(2)  Most  consistent  reception  of  stations 
6,000  to  8,000  miles  distant— 117  pro- 
grams in  three  months. 

(3)  Brought    in   6   different   stations  in  2J^ 
hours — all  over  6,000  miles 

Full  sized  blue  prints  with  com- 
plete instructions  showing  how  to 
make  exact  duplicate  of  this 
marvelous  receiver. 

PRICE  $5 

Story  of  development  and  proofs  of  records 
sent  on  receipt  of  stamped  and  addressed 
envelope. 

Scott  Radio  Laboratories 

35  S.  Dearborn  St.,  Chicago 

Dealers  and  Jobbers  Write 


The  Five  Tube 


/ 


I  Set  which 
startled 
the  World 

saenefl 

The  Greatest  Value 
Ever  Offered  in  A 
Radio  Receiving  S*t 


h 


At  Authorized  Dealers 


«D" 


B"  Battery  Eliminator 

q/-i     For  the  price  of  "B" 

mmJ\J     Batteries  it   is  now 

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Battery  Eliminator 

*  that   is    guaranteed 

foreighteen  months. 

For  direct   current    only. 
POWER   SUPPLY  CO. 

320  E.  176  St.         N.  Y.  City 


Myers  Tubes  Now  to  be  Made 
at  Cleveland 

The  radio  public  in  general  and  radio 
fans  in  particular  will  unquestionably 
welcome  the  Myers  Radio  Corporation, 
which  will  manufacture  the  Myers  tubes 
in  the  United  States,  their  plant  being 
located  in  Cleveland. 

The  heartbreaking  experiences  of  the 
radio  inventors,  the  privations  they  were 
compelled  to  suffer,  the  patent  legal 
battles,  and  their  undying  tenacity, 
made  the  present  radio  reception  possible. 
Fortunately,  the  Myers  Radio  Corpora- 
tion was  able  to  overcome  these  difficul- 
ties, its  Board  of  Directors  made  up  of 
prominent  and  representative  Cleveland 
business  men. 

Prior  to  December  1922,  Myers  Tubes 
were  manufactured  in  Jersey  City. 
Their  type  of  construction  was  entirely 
different  from  the  ordinary  style  of  tube 
made,  in  that  the  Myers  tube  elements 
were  small,  reducing  tube  capacity  and 
having  the  leads  separated,  that  is,  the 
leads  of  plate  and  positive  filament 
were  brought  out  of  one  end  of  the  tube 
and  the  leads  of  the  grid  and  negative 
filament  out  of  the  opposite  end. 

The  Myers  tubes  were  a  success  and 
the  demand  was  beyond  any  possible 
supply.  Of  course  at  that  time  there 
were  but  few  radio  sets  in  use  and  the 
users  were  anxious  to  have  their  families 
and  their  neighbors  enjoy  the  broad- 
casting of  the  one  or  two  broadcasting 
stations  then  in  operation. 

Just  at  a  time  when  production  was 
being  speeded  up  to  cope  in  a  small 
measure  with  the  pressing  demand,  a 
legal  patent  battle  unprecedented  in  the 
annals  of  radio  ensued,  with  the  result 
Myers  tubes  were  compelled  to  move  to 
Canada,  where  the  complications  with 
respect  to  the  three  element  patent  did 
not  exist.  It  is  understood  the  Company 
now  owns  the  patents  and  patent  appli- 
cations on  the  styles  of  tubes  they  are 
going  to  manufacture  and  the  machinery 
used  in  the  process  of  manufacturing. 

The  Myers  Radio  Corporation  is 
equipping  a  factory  where  they  will  not 
alone  make  the  famous  double  end  type 
of  tubes,  but  also  all  types  commonly 
used  in  all  receiving  sets  now  on  the 
market.  They  claim  certain  improve- 
ments that  will  give  clarified  reception 
with  greater  amplification.  The  factory 
is  being  equipped  for  a  large  production 
capacity. 


O'Neil  Loud  Speaker  For 
Canadian  Marconi 

The  O'Neil  Manufacturing  Company, 
whose  plant  is  at  4738  Hudson  Boulevard, 
West  New  York,  N.  J.,  are  the  builders 
of  the  Audiphone  loud  speaker,  which 
incorporates  the  three-way-control  bal- 
anced armature,  laminated  electro  mag- 
net, large  permanent  magnet,  and  India 
Mica  diaphragm. 

The  factory  is  located  on  the  boulevard 
and  is  an  attractive  little  place  with 
plenty  of  light  and  good  air.  Raymond  R. 
O'Neil,  who  is  at  the  head  of  the  organiza- 
tion, is  assisted  by  Mrs.  O'Neil,  a  score 
of  engineers,  and  assemblers. 

Among  the  firms  for  which  the  O'Neil 
Company  supplies  loud  speakers  is  the 
Marconi  Wireless  Company  of  Canada. 
*    Tested  and  Approved   by  RADIO   AGE    * 


Irelan's  Latest 

"Wonder" 

Coil 

DISTANCE  VOLUME 

SELECTIVITY 


Price  $6.50 
Manufactured  by  the  Inventor 

A.  E.  IRELAN, 

Sharon  Hill,  Pa. 
Distributed  by 

RADIO  SERVICE  CO. 

3704  N.  6th  St.,  Phila.,  Pa. 
Dealers  Write  for  Our  Proposition 


The  Indoor  Aerial  that 
is  more  selective  and 
more  efficient  than  any  outside 
antenna.  This  device  has  estab- 
lished an  enviable  D-X  record  in 
the  congested  district 
of  Chicago  for  the 
past  two  years. 

Seal  prepaid  on  receipt  of  money  order  ' 

AERION  AERIAL  CO. 

7255  CORNELL  AVE 
CHICAGO.  ILL 


past  i 
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A£ 


record  in 

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o    £ 


Free,  big  Radio  Catalog 
and  Guide  brimful  of  new- 
est Ideas,  over  100  special  hook- 
ups and  illustrations.  You  save 
as  much  aa  50%  on  seta  and 
parts.  Be  sure  to  get  this  thrifty  ; 
book  before  you  buy.  It  puts 
money  In  your  pocket.    Shows 

D  standard  radio  parts,  seta, 
kits,  ail  reliable,  guaranteed 
goods.  Please  Include  name 
of  radio  fan  to  whom  we  may 
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or  postal  now. 


[104-126  9.  Canal  St.,  Chicago,  U.  S.  A.  | 


$1.50  for  Your  Old  Radio  Tubes 

regardless  make  or  condition,  toward  pur- 
chase   of    each    new    standard    $2.50    tube. 
Positively      guaranteed.      We    do   not      sell 
re-built  or  bootleg-  tubes.     Agents  wanted. 
SUPER-SERVICE  LABORATORIES, 
Dept.    B,   Room   58. 
39    West    Adams,    Chicago,    III. 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


55 


Build  a  B-T  Counter  phase  Six 

New    Construction    Plans 
Eliminate  Chances  of  Error 

A  six  tube  receiver  with  three  stages  of  radio  frequency, — a  set  that  gives  distant  reception 
with  only  a  short  indoor  aerial  and  is  the  last  word  in  selectivity,  yet  uses  only  two  tuning  dials. 

Such  a  receiver  is  the  new  B-T  "Counterphase"-Six,  which  a  leading  radio  editor  terms,  "The 
only  new  circuit  of  the  season." 

You  can  build  this  master-set  yourself.  The  B-T  system  of  instruc- 
tions makes  it  easy  for  the  most  inexperienced  to  construct  a 
"Counterphase."  B-T  Kits  contain  the  essential  parts  together 
with  all  radio  frequency  leads  cut  and  ready  to  place  in  position.  A 
series  of  progressive  charts  in  nine-color  combinations  show  exactly 
where  each  wire  goes.  Printed  instructions  take  you  through  the 
whole  job  step  by  step.  You  can't  go  wrong,— never  before  has  there 
been  such  an  easy  way  to  build  a  receiver.  A  set  of  these  instructions 
is  included  in  each  kit. 

You  can  also  build  a  "Counterphase"  with  two  or  one  stage  of 
radio  frequency  for  use  with  an  outdoor  antenna. 

See  your  dealer  about  a  "Counterphase."  Ask  him  to  show  you 
the  new  B-T  method  of  construction. 

"The  Best  we  Ever  Tested—" 

says  a  leading  laboratory  of  the  "Euphonic"  Audio  Transformer. 
Tone  quality  is  the  outstanding  feature  of  this  transformer.  We  have 
named  it  the  "Euphonic"  because  it  is  "Pleasing  to  the  Ear." 

In  addition  to  being  a  transformer  of  merit  the  "Euphonic"  possesses  an  added 
mechanical  feature  that  eliminates  howling  and  distortion  due  to  crossed  or  too  close 
leads.  Case  and  brackets  are  so  designed  that  the  "Euphonic"  may  be  mounted  in 
any  desired  position  with  the  terminals  always  in  place  for  correct  wriing. 

This  feature  is  found  only  on  B-T  "Euphonies." 

Condensers  Built  as  only  B-T  Can  Build 

Never  has  there  been  a  condenser  that  made  the  success  with  radio  engineers,  tech- 
nical writers,  experienced  set  builders,— the  men  who  know-  that  did  the  B-T  "Life- 
time" Condenser.  Its  mechanical  and  electrical  superiority  appealed  to  them  from 
the  first. 

You  can  now  secure  this  same  quality  in  Straight  Line  Frequency.  You  can  pay 
more  for  condensers  but  you  can't  buy  as  much.  That's  why  we  print  on  every  carton, 
"If  you  don't  find  it  better,  send  it  back." 

80  Pages  of  Radio 


Ratio:  2.2  to  1_ Price  $5.00 

4.7  to  1 Price    5.75 


in  the  new  80  page  8th  Edition  of  "Better  Tuning."  Tells  all  about  the 
"Counterphase,"  new  apparatus,  current  discussions  of  radio,  etc. 
Postpaid,  10  cents. 

Circulars  on  B-T  products  sent  free  on  request. 


SLF-13,  Capacity  .00025.  Price  $5.50 
SLF-17,  "       .00035.  .Price    5.75 

SLF-23,  "  .0005.   Price     5.75 


Bremer-Tully  Mfg.  Co. 


532  S.  Canal  St. 


* 


Chicago,  111. 


*    Tested  and  Approved  by  RADIO  AGE    * 


56 


RADIO  AGE  for  December,  1925 


The  Magazine,  of  the  Hour 


for  if  our  I 
&  battery 

eliminator 


REX  answers  the  eliminator 
i,  problem.  The  B  Battery- 
eliminator  equipped  with  Magna- 
tron  Rex  tubes  works  day  in  and 
day  out . — ■  silently  and  economi- 
cally. 

MagnatronRex  is  the  product  of 
long  research  by  the  oldest  ex- 
clusive manufacturers  of  thermionic 
valves  in  the  country.  It  has  been  de- 
signed primarily  and  only  for  eliminator 
work. 

Magnatron  and  Excellence  have  come 
to  mean  one  and  the  same  thing.  Im- 
partial laboratories  and  radio  engineers 
throughout  the  country  have  certified 
this.  Their  reports  explain  why  Magna- 
trons  in  your  set  will  make  it  function 
better. 

Your  dealer  has  the  Rex  as  well  as  the 
other  Magnatrons.  Ask  him  today! 
They  list  for  only  $2.50. 


Write  for  your  FREE  copy  of 
"Pot  Pourrt . — ■  a  snappy  review  of 
mirth  and  music  \  to  Dept.A  , 
Connewey  Electric  Laborator- 
ies, Magnatron  Building,  Hobo\en, 
7s[ew  Jersey. 

West  Coast  supfliedjrom  complete  stocks  carried  by 

PACIFIC  RADIO  LABORATORIES 

256  So.  Los  Angeles  St. 

Los  Angeles,  Calif. 


Dealers — if  you  want  the  best  pro- 
ducts, the  fastest  shipments  and 
the  most  liberal  discounts,  write  on 
your  letterhead  for  our  catalog 
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616  beautiful  copper  etched  American, 
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each   with   the  call  letters  of  a  sta- 
tion,     FREE     with      Ideal     48-page 
Radio     Stamp     Album     and     Log. 
Also    contains    complete    list    of    sta- 
tions   both    alphabetically    and    by 
call  letters.     As  you  hear  new  sta- 
tions, just  put  the  proper  stamps  in 
your  album.  Album  and  stamps  be- 
come a  permanent  and  interesting 
record  of  the  stations  you  receive. 
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Tuning  Your  Radio  By 
Chart  Curves 

(Continued  from  page  21) 
lengths    as    follows: 

Take  a  sheet  of  paper  eleven  inches 
square.  Rule  off  a  one-inch  margin  on 
the  lower  and  left-hand  edges,  and  in  the 
larger  space  draw  faint  intersecting  lines  a 
half  inch  apart,  as  in  Figs.  1  and  2.  Num- 
ber the  bottom  horizontal  line  0,  the 
one-inch  line  above  it  10,  the  two-inch 
line  20,  and  so  on  up  to  and  including 
100  to  correspond  with  the  numbers  on 
the  tuning  dials.  Now  number  the  left- 
hand  vertical  line  200,  the  one-inch  line 
to  the  right  240,  and  two  inch  line  280, 
and  so  on  up  to  600,  to  cover  the  meter 
wavelength  range  of  the  broadcast 
receiver. 

Suppose  the  first  station  recorded  has  a 
wavelength  of  326,  and  the  dial  settings 
which  brought  it  in  are  32,  30  and  28 
for  dials  No.  1,  2  and  3  respectively. 
Take  a  rule  and  place  it  parallel  to  the 
vertical  lines  so  as  to  pass  through  a 
point  on  the  lower  line  between  the  320 
and  360  points,  which  will  coincide  with 
the  326  meter  position.  Place  dots  at 
the  edge  of  the  rule  at  the  dial  positions 
32,  30  and  28.  These  dial  positions  are 
found  by  consulting  the  dial  position 
figures  in  the  left  hand  margin  of  the 
paper;  after  finding  the  line  marked  30, 
the  location  of  dial  positions  32  and  28 
can   be  estimated. 

The  Dial  Settings 

IN  a  similar  way,  make  dots  represent- 
ing the  dial  settings  of  three  or  four 
other  stations  whose  wavelengths  range 
up  to  550.  Some  way  of  distinguishing 
the  dots  should  be  employed  such  as 
marking  the  dial  No.  1  dots  red,  the  dial 
No.  2  dots  blue,  and  the  dial  No.  3  dots 
black.  Now  draw  a  smooth  curve  line 
passing  through  all  of  the  dial  No.  1 
dots.  Draw  a  similar  line  passing  through 
the  dial  No.  2  dots,  and  a  third  passing 
through  the  dial  No.  3  dots. 

With  these  three  curves  drawn,  it  is  a 
simple  matter  to  bring  in  any  station 
whose  wavelength  is  known.  For  in- 
stance, if  the  desired  station  has  a  wave- 
length of  400  meters,  lay  the  ruler  down 
on  the  curve  chart  on  the  vertical  400 
meter  line.  The  points  on  the  horizontal 
lines  at  which  the  ruler  intersects  the 
three  curves  will  indicate  the  positions  to 
which  the  dials  must  be  turned  in  order 
to  bring  in  the  desired  station  by  means 
of  this  home-made  curve  chart.  Thus  the 
radio  fan  who  desires  to  tune  in  various 
stations,  whose  wavelengths  are  known, 
can  do  so  conveniently  by  preparing  a 
curve  chart  for  his  particular  set. 

The  next  set  which  we  will  discuss  is 
the  super-heterodyne,  which  is  one  of 
the  most  complicated  sets  in  its  mechani- 
cal construction  but  is  one  of  the  easiest 
to  operate.  There  are  usually  three 
controls,  one  of  which  is  for  adjustment 
of  the  battery  current  to  the  vacuum 
tubes.  This  adjustment  should  be  made 
as  usual.  In  this  case  use  a  low  setting 
to  start  with.  The  other  two  controls 
serve  to  select  the  stations,  one  of  them 
tuning  the  loop  circuit  while  the  other 
tunes  what  is  called  a  "driver"  or 
"oscillator."  These  sets  are  usually  de- 
signed so  that  when  signals  are  to  be  re- 
ceived the  positions  of  the  two  selectors 
will  be  very  nearly  but  not  quite  the 
same. 

The  principle  on  which  this  set  operates 
is  that  the  frequency  of  the  "driver" 
(Turn  to  page  58) 


Tested  and  Approved 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


57 


Resistor  Manual 

The  Handbook  of  Resistance  Cou- 
pled Amplification  at  best  radio  deal- 
ers 25c.  Direct  by  mail,  postpaid  30c. 

CLIP  THIS  COUPON 

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well  as  all  necessary  binding  posts,  are  supplied.  There  is  nothing  to  do  but 
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Thousands  have  changed  over  their  amplifiers  to  the  resistance  coupled  system 
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remains  sweet  and  true.  Daven  Power  Tube  Type  MU-6  is  recommended 
for  the  last  or  output  stage  in  any  set. 

Any  Daven  dealer  will  show  you  how  to  hook  up  the  Daven  Super -Amplifier. 
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*    Tested  and  Approved  by  RAPIO  AGE    ¥ 


58 


RADIO  AGE  for  December,  1925 


Now-Plate  Voltage 
for  any  Set  r-*  and 
You  can  afford  it/ 

First  Cost  Economy  now  makes  it  possible  for  EVERYONE  to 
obtain  efficient  "B"  current  supply  right  from  their  electric  light 
socket.  Now  one  of  the  biggest  improvements  in  modern-day  radio 
reception  is  placed  within  the  reach  of  all.  Think  of  it!  A  perfect, 
always  efficient  source  of  plate  voltage  for  any  set  for  $9.75!  It 
marks  a  revolutionary  step  forward  and  will  be  welcomed  by  mil- 
lions of  radio  enthusiasts. 

Ferbend 

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The  price  of  this  remarkable  new  unit  is  spectacular  in  more  than 
one  way.  Besides  saving  you  from  $15  to  $50  it  is  amazingly  low 
considering  the  quality  and  superiority.  You  may  ask  "how  could  it 
be  possible  to  build  such  a  unit  for  the  ridiculously  low  price  of 
$9.75?"  True  mechanical  genius  and  resourcefulness  alone  are  re- 
sponsible. But  the  logical  way  to  answer  this  question  is  to  equip 
your  set  at  once  with  this  marvelous  unit  and  be  convinced. 

ASK  YOUR  DEALER— OR  SEND  DIRECT 

Until  nation-wide  distribution  is  com- 
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ULTI^VSRHISI^ 

TUNINGp      control 


PHENIX  RADIO  CORP.,  1 16-F  East  25  Si.,  N.Y.  C. 


The  Magazine  of  the  Hour 

Tuning  Your  Radio  By 
Chart  Curves 

(Continued  from  page  56) 
shall  be  different  from  the  frequency  of 
the  incoming  waves  by  a  certain  amount. 
Thus  there  are  two  positions  of  the  driver 
for  each  position  of  the  loop  tuner,  one 
position  corresponding  to,  the  condition 
when  the  driver  is  operating  at  a  higher 
frequency  than  the  incoming  waves  and 
the  other  when  the  driver  is  at  a  lower 
frequency  than  the  incoming  waves. 
Therefore,  the  proper  method  is  to  set 
the  loop  tuner  and  then  turn  the  driver 
slowly  in  either  direction  from  a  position 
corresponding  to  the  setting  of  the  loop 
tuner  until  the  sounds  indicate  that  the 
"air  is  open."  As  in  the  case  of  the  tuned 
radio  frequency  set  it  will  be  found  con- 
venient to  draw  the  curve  chart  already 
described  that  different  stations  may  be 
easily  selected.     See  Fig.  2. 

It  will  be  noticed  on  the  super-hetero- 
dyne that  for  every  position  of  the  loop 
tuner  or  "selector  No.  1,"  which  cor- 
responds to  the  wavelength  of  a  given 
station,  that  there  are  two  distinct 
settings  of  the  "oscillator  dial"  or  "selec- 
tor No.  2,"  at  which  the  signals  or  broad- 
casting from  that  particular  station  will 
come  through.  A  curve  should  be  drawn 
for  each  of  these  two  positions.  A  great 
advantage  of  making  both  these  curves  is 
that  in  case  of  interference  from  a 
powerful  local  station  at  one  setting  of 
the  oscillator  dial  or  "selector  No.  2,"  it 
may  be  immediately  changed  to  the  other 
setting  by  reference  to  the  curves. 

The  next  type  of  receiver  to  be  de- 
scribed, the  single  circuit  regenerative 
receiver,  has  several  tuning  dials,  and  no 
accurate  curve  can  be  made  for  tuning 
this  set,  because  several  variables  such  as 
size  of  antenna,  temperature  of  filaments, 
etc.,  will  affect  the  setting.  However, 
under  any  given  condition  a  curve  for  the 
tuning  dial  only  made  in  the  manner 
already  described  will  serve  as  a  rough 
guide  in  finding  new  stations  whose  wave- 
lengths are  known. 


'carpet 


An  Informal  Chat 
with  WGY 

(Continued  from  page  31) 
exploiting  of  an  invention  for 
covered  carpet  tacks"  and  it  is  really 
amusing,  as  all  Wallingford  stories  are. 
Not  long  after  the  play  was  broadcast 
the  studio  received  a  visit  from  a  woman 
who  appeared  very  much  excited. 

"You  have  exposed  my  secret,"  she 
said.  "I  have  been  working  for  a  con- 
siderable length  of  time  on  this  proposi- 
tion and  just  as  I  get  it  perfected  I 
hear  you  broadcasting  it  to  the  world, 
telling  every  one  about  it." 

The  microphones  do  not  come  into 
view  at  the  first  survey  of  the  studio. 
The  first  thought  of  the  uninitiated  per- 
son, upon  stepping  into  the  studio,  is 
that  a  considerable  number  of  floor 
lamps  are  used.  Several  of  them  with 
small  ornate  silk  shades  are  located  in 
various  sections  of  the  room.  Closer 
inspection,  however,  discloses  the  fact 
that  instead  of  electric  lights,  the  fringe 
of   the   shade   conceals   the    microphone. 


H-    Tested  and  Approved  by  RADIO  AGE    tf 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hoar 


59 


Send  for  this  J* Am^T  1926  Catalog  of 

radio  msssSi  RADro 

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60 


RADIO  AGE  for  December,  1925 


What  to  give  the  radio  fan 

Give  him  a  two-ampere  Tungar  if  he  has  a 
storage  battery  of  any  kind.  It  will  charge 
all  his  radio  batteries  and  his  auto  battery, 
too. 

Or,  for  bigger  jobs,  give  him  a  five-ampere 
Tungar— built  to  do  the  same  work  but  to 
do  it  more  than  twice  as  fast. 

Every  man  who  has  a  storage  battery 
wants  a  charger.  And  every  man  who  wants 
a  charger  wants  the  original  General  Electric 
bulb  charger— the  Tungar. 


The  Tungar  is  a  G-E 
product,  developed  in 
the  Research  Labora- 
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tric. ' 

The  new  Tungar  char- 
ges any  make  and  size 
of  storage  battery:  ra- 
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ies ap  high  as  96  vol  s 
in  series. 

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Two  ampere  size  $18.00 
Five  ampere  size  $28.00 
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BATTERY   CHARGER 


Tungar— a  registered  trademark— is  found  only 
on  the  genuine.      Look  for  it  on  the  name  plate. 
Merchandise  Division 
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CHICAGO  ILLINOIS 

*    Tested  and  Approved   by   RADIO   AGE    * 


The  Magazine  of  the  Hour 

Dean  of  Radio 
Adventurers 

( Continued  from  page  36) 
tropical  breezes  and  warm,  soothing  sun- 
beams  that    meet    the    dashing   seaman! 
"That's  the  life,"   he  told    himself — and 
his  mind  was  made  up. 

Now  we  find  A.  F.  Henninger,  Jr., 
the  proud  radio  operator  on  a  South 
American  banana  boat.  In  fact,  Hen- 
ninger says  that  during  those  many 
months  that  every  man,  woman  and 
child  in  North  America  was  loudly 
singing,  "Yes,  We  Have  No  Bananas," 
he  can  personally  vouch  that  his  banana 
boat  brought  millions  of  bananas  to 
the  shores  of  the  American  Country. 
It  would  be  a  simple  matter  to  picture 
Henninger  excitedly  broadcasting 
through  his  banana  boat  transmitter 
some  such  chaotic  announcement.  "Amer- 
icans! Will  arrive  in  two  days  with 
full  cargo  of  bananas.     Famine  averted!" 

Safely  in  the  port  of  New  Orleans 
with  his  valuable  bananas,  Henninger 
was  approached  by  a  dark  skinned 
almond  eyed  native  of  a  prominent 
South  American  Republic.  They  joined 
in  a  secret  mysterious  conference.  Hen- 
ninger's  companion  proved  to  be  a 
revolutionist.  The  proposition  was  sim- 
ply this,  Henninger  was  to  go  to  Central 
America  and  take  charge  of  the  revolu- 
tionist radio  equipment.  He  was  to 
be  their  Official  Radio  General  for  a 
matter  of  $350  a  week.  Henninger 
had  been  searching  for  adventure — 
and  here  it  was  spread  out  on  a  platter 
ready  to  be  taken  at  an  instant's  notice. 

A  Real  Revolutionist 

TTENNINGER  became  a  high-salaried 
■-•"■  revolutionist.  Careful  as  the  revolu- 
tionists had  been  in  their  plans  they 
must  have  overlooked  some  important 
link  in  their  scheme  for  it  was  not  many 
weeks  later  that  the  revolution  was 
lost,  the  treasury  was  lost  and  the  radio 
apparatus  was  lost — and  Henninger  found 
himself  in  the  dense  jungles,  with  a 
foot  made  useless  and  painful  by 
nationalist's  bullet.  For  two  weeks  he 
wandered  about  the  forest,  trying  to 
get  himself  out — but  so  weak  and  hun- 
gry that  what  strength  he  had  left 
could  only  be  used  to  help  him  find 
berries   and   herbs   for   his   meals. 

This  last  experience  caused  him  to 
spend  several  months  in  a  New  York 
hospital.  Later  he  became  a  chief 
engineer  for  radio  manufacturers.  And 
now  we  find  him  a  quiet,  unassuming 
radio  manufacturer  whose  taste  for 
adventure  seems  to  have  departed 
entirely.  Possibly  his  adventures  are 
over,  but  one  can  never  tell!  He  lives 
in   Chicago. 


The  January  Radio  Age 
Model  will  Be 
Easier  to  Build 


61 


9he  QrtattSt  Mime.  inHadio 
A  Peerless  Value  from  the  Master  Scientist  of  Radio 


CELDOM  are  the  finer  things  of  life  introduced  at  pop- 
*J  ular  prices.  The  cost  of  originating  the  new  usually 
prohibits  low  price. 

But  here  is  a  notable  exception — the  De  Forest  F-5-M 
Radiophone,  a  masterpiece  in  performance,  quality  and 
dignified  beauty,  from  the  master  mind  of  radio  science. 

Everything  about  this  marvelous  set  is  exceptional.  The 
circuit  is  new — and  ingenious.  Known  as  the  De  Forest 
Balanced  Circuit,  it  gives  to  radio  tone  the  rich  realism  of 
life.  Low  and  soft  tones  that  usually  die  away  in  a  misty 
blur  are  reproduced  distinctly  and  musically.  Very  high 
tones  that  seem  to  climb  into  the  infinite  and  flutter  away 
like  white  butterflies  against  a  blue  summer  sky  are  borne 
to  your  ear  with  a  clearness  and  sweetness  new  to  radio 
devotees.  Individual  parts  in  quartette  and  choral 
harmony  are  intensified— something  new  in  reception. 

This  self-same  circuit  also  contributes  economy  to 


operation.  It  reduces  the  drain  on  batteries,  thereby 
lengthening  "B"  battery  life  and  the  interval  of  recharg- 
ing or  replacing  "A"  batteries. 

Refreshing,  also,  is  the  manner  in  which  this  new  cir- 
cuit tunes  in  stations  .  .  .  without  scraping  and  whistling. 

New  power  qualities,  distance  mastery,  station  sep- 
aration and  volume  are  added  by  other  newly  devised 
mechanisms.  And  art  intervenes  to  add  the  final  touch 
.  .  .  grace  and  symmetry  in  cabinet  design,  the  tone  re- 
producer in-built  and  out  of  sight,  "B"  batteries  housed 
in  a  compartment  within  the  cabinet. 

Yet  the  price  is  only  $110!  (Western  prices  slightly 
higher.)  See  and  hear  the  F-5-M  at  your  nearest  Author- 
ized De  Forest  Dealer's. 

Price  range  of  De  Forest  Radiophones — $85  to  $450. 
DE  FOREST  RADIO  COMPANY 

Jersey  City,  N.  J. 


For  better  reception  and  longer  tube  life  always 

buy  De  Forest  Audioos.  There's  a  special  one  for 

each  socket.    De  Forest  invented  the  radio  tube 

—  there  can  be  none  finer,  $3.00 


«/ 


*    Tested  and  Approved  by  RADIO  AGE    * 


62 


RADIO  AGE /or  December,  1925 


The  Magazine  of  the  Hour 


Meet  the  Play  Boy  of  the 
Dakotas 

(Continued  from  page  37) 

He  sees,  from  the  moment  the  micro- 
phone is  cut  in  up  in  the  WGR  operating 
room,  the  lonely  places  out  on  the  prairies 
— the  home  where  the  radio  is  chief 
means  of  entertainment.  He  sees  the 
old  couple,  left  alone  by  their  children 
who  have  gone  out  into  the  world,  whose 
loneliness  is  lightened  hy  the  melodies 
which  he  is  able  to  bring  forth.  He  sees 
the  group  of  youths  and  maidens  dancing 
to  the  tunes  of  his  artists  obtained  by 
medium  of  the  loud-speaker  set  on  the 
stage  of  the  little  village   "opera    house." 

And  for  that  reason  Harold  Gieser 
pays  special  attention  to  the  radio 
audience.  For  that  reason  Harold  Gies- 
er  plays  as  much — perhaps  more — to 
the  radio  audience  when  the  microphone 
is  open  as  to  the  Statler  audience. 

Many  fans  complain  that  some  direc- 
tors repeat  indiscriminately  and  inter- 
minably. Harold  Gieser  sees  to  it  that 
a  selection  is  rarely  if  ever  repeated  to 
the  radio  audience  during  any  one  week. 
That  is  why  WGR  fans  always  listen  to 
the  Vincent  Lopez  bunch  at  Buffalo 
when  they  are  on  the  air — always  the 
variety  with  the  uniform  quality.  Harold 
Gieser  takes  great  pride  in  the  fact  that 
he  has  built  up  what  he  calls  his  "radio 
repertoire"  of  more  than  seventy-five 
different  selections. 

What  Does  He  Do? 

\  NYONE  want  to  know  what  a  jazz 
-^*-  orchestra  director's  day  is  like? 
Well,  Harold  Gieser  is  up  at  ten  in  the 
morning — breakfast — and  then  probably 
off  to  a  rehearsal  from  eleven  until  about 
two  in  the  afternoon.  Meet  friend  wife 
for  luncheon.  Nothing  to  do  then  until 
about  five-thirty  except  shop,  or  write 
letters,  or  work  on  an  orchestration,  or 
mess  around  with  the  orchestra's  library, 
or  take  a  little  ride  in  the  car,  or  meet 
someone  who  wants  a  try-out,  and  so  on 
and  so  on. 

About  five-thirty — something  to  eat — 
a  fresh  shave — fly  into  the  dear  old 
Tuxedo  and  so  to  the  hotel  all  set  to 
begin  the  dinner  music  program  at  six- 
thirty.  Off  for  a  bit  in  the  middle  of 
the  evening  but  on  the  job  with  a 
vengence  from  eleven  until  two  or  there- 
abouts in  the  morning — thence  home, 
but  not  to  bed,  but  to  listen  in  on  some 
of  the  far  distant  stations  to  see  what 
kind  of  jazz  is  produced  in  various  parts 
of  this  country  and  Canada  and  to  pick 
up  new  ideas  for  arrangements,  and  then 
to  bed  at   three  or  four  or  five  o'clock. 


New  Crystals 
Tested 

Specimens  of  the  Alkemite  crystals 
manufactured  by  the  Mineral  Novelty 
Co.,  Joplin,  Mo.,  have  been  received  at 
the  Radio  Age  office  and  tested,  having 
been  found  uniformly  good.  Instead  of 
the  usual  Wood's  metal  mounting  the 
Alkemite  crystals  are  set  into  a  three 
prong  base  which  grips  the  .crystal 
tightly. 


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CHICAGO,  U.  S.  A. 


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Big  Money  in  Radio 

Demand  for  high  pay  radio  men  is  so  great  that  a 
big  Kansas  City  wholesale  concern  is  now  fitting 
men  free  to  get  into  the  radio  business  for  them- 
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Agents  wanted,  write  for  par- 
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RADIO  AGE  for  December,  1925  The  Magazine  of  the  Hour  63 

POWKLyS  (Ms_(hdsei)! 

UsedmllMBE©MMModelMm 


1.  System  of  winding  localizes  magnetic  field. 

2.  Flat-Sided   units   give    high    mutual    induc- 
tance, lowering  resistance. 

3.  New  design  prevents  coil  from  picking  up 
interference. 

4.  Ribbed  frame  of  hard  rubber  lowers  losses. 

5.  End    ribs   protect   coil. 

6.  Windings  with  wide  air  spacing  lower  dis- 
tributed capacity. 

7.  Low  primary  to  secondary  capacitive  coup- 
ling, increases  power. 

8.  Both  binding  posts  and  lugs  provided. 

9.  Mounting     bracket     also     supports     frame. 
Less  metal  parts. 

10.  Design    of    primary    gives    extremely    high 
amplification. 

11.  Coil    extremely    compact.       3"'    high    with 
bracket. 

12.  No  coupling  between  coils. 


The  latest,  most  improved  Coil  on  the  market 
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*    Tested  and  Approved  by  RADIO  AGE    * 


64 


RADIO  AGE  for  December,  1925 


ORIOLE! 


The  Most  Amazing  Performer 

You've  Ever  "Tuned  In" 


* 


Oriole — Model 7 — 5  luoes 


Oriole  radio  receivers  step  right  out  and  make  astounding 
records  on  distant  stations — they  give  exceptional  volume 
— unequaled  for  clarity  and  sweetness  of  tone — the  most 
selective,  sharpest  tuning  set  you  ever  played  with — 
you'll  be  "sold"  on  the  ORIOLE  the  minute  you  turn  its 
dials. 

Model  7 — 5  Tubes.     Model  8 — 4  Tubes. 
Write  for  illustrated  folder. 

Dealers:     There  is  some  exclusive   territory  open- 
ask  for  details. 

W-K  Electric  Co. 

KENOSHA,  WISCONSIN 


While  They  Last! 

We  have  a  limited  number  of  the  1925  RADIO  AGE  ANNUALS, 
the  big  $1.00  book,  and  will  send  one  free  of  charge  to  each  of  the 
lucky  fans  who  use  this  coupon  and  send  in  their  subscription  for 
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Radio  Age,  Inc., 

500  No.  Dearborn  St., 

Chicago,  Illinois. 

Send  me  a  copy  of  the  1925  RADIO  AGE  ANNTj„.£,  free,  and  enter  my 

subscription  for  the  RADIO  AGE  beginning  with  the issue  at 

the  regular  price  of  $2.50.      Enclosed  is  my  check  (or  money  order.) 

Name 

Address.- 

City state 


The  Magazine  of  the  Hour 
A  British  View  of  Broadcasting 

(Continued  from  page  38) 

possible  for  Russia,  for  instance,  to  erect  a 
very  powerful  station  from  which  they 
might  force  upon  the  listeners  of  neigh- 
bouring countries  and  even  of  distant 
countries,  the  harm  or  good  of  their 
propaganda.  This  fact  must  be  borne  in 
mind  to-gether  with  the  question  of 
interference.  The  whole  point  turns 
round  the  question:  should  a  country  be 
allotted  a  large  number  of  weak  stations 
distributed  over  its  whole  area,  or  should 
it  have  one  powerful  one  in  the  centre? 
This  latter  policy  is  not  always  possible 
because  the  geographical  centre  is  not 
always  the  political  centre,  we  have 
countries  like  France,  where  the  capital 
is  four  hours  from  one  frontier  and  twelve 
hours  from  the  other.  This  means  that 
their  powerful  station,  if  designed  with 
a  view  to  supplying  the  whole  of  the  in- 
habitants, will  also  cover  with  equal 
strength  other  countries  too.  Here  there 
is  great  room  for  co-ordination,  and  no 
doubt  from  the  numerous  discussions 
which  are  bound  to  arise  of  so  complex  a 
subject,  many  solutions  will  be  put  for- 
ward, among  which  a  good  one^which 
may  be  adhered  to. 

From  an  international  point  of  view, 
there  is  also  the  question  of  hours  of 
transmission.  No  doubt  stations  are 
mainly  concerned  with  their  near  lis- 
teners, but  they  sometimes  forget  that 
these  same  listeners  are  very  likely  to 
become  wireless  enthusiasts  and  to  pay 
their  license  so  as  to  be  able  to  listen  to 
distant  stations.  In  other  words,  the 
position  is  very  much  like  that  of  foreign 
postage.  A  man  in  England  pays  the 
B.  B.  C.  for  his  license,  but  listens  to  a 
German  station  to  which  he  does  not 
pay.  As  against  this,  a  man  living  in 
Germany  pays  the  German  broadcasting 
stations  and  occasionally  listens  to  the 
British  concerts,  and  everybody  is,  as 
it  were,  quits.  But  this  is  not  really  the 
case;  Great  Britain  is  situated  on  the 
western  edge  of  Europe,  consequently 
its  time — Greenwich  Mean  Time-^is 
ahead  of  the  other  times  in  the  centre 
and  eastern  parts  of  Europe  which  use 
Central  European  Time  (one  hour  behind 
our  own)  and  Eastern  European  Time 
(two  hours  behind  our  own).  For  a  man 
living  in  Budapest,  the  Savoy  bands  go 
on,  on  Saturdays,  until  2  o'clock  in  the 
morning,  whereas  his  own  stations 
which  close  down  at  10  o'clock  in  his 
country,  cannot  be  heard  later  than 
8  o'clock  in  England.  There  is  obviously 
an  unfairness  here,  since  at  that  time  the 
British  stations  are  working  on  full 
power  and  the  British  listener  conse- 
quently has  not  so  good  an  opportunity  to 
tune  in  the  Hungarian  stations.  How 
can  this  be  remedied?  One  good  way 
would  be  for  all  broadcasting  stations 
to  agree  to  give  special  transmissions 
say  once  a  month,  at  special  hours  which 
would  render  it  easier  for  the  distant 
listeners  to  tune  in.  It  does  not  appear 
to  me  much,  to  ask  every  station  to  give 
a  special  programme  say  of  two  hours 
(Continued  on  page  67) 


*    Tested  and  Approved  by   RADIO  AGE    * 


RADIO  AGE  for  December,  1925 

Langmuir  Finally  Gets 
Patent 


A  basic  patent  for  the  highly  evacuated 
tube,  used  extensively  in  radio,  X-ray 
work  and  in  repeaters  used  in  long 
distance  telephony,  has  recently  been 
granted  the  General  Electric  Company 
by  the  U.  S.  Patent  Office.  This 
tube  was  invented  by  Dr.  Irving  Lang- 
muir, assistant  director  of  the  General 
Electric  research  laboratory,  in  1912, 
but  because  of  contests  the  patent  was 
not  granted  until  recently. 

The  tube  is  characterized  by  its  hard, 
constant  vacuum,  by  its  freedom  from 
visible  discharge  and  other  gaseous 
effects  and  by  its  steadiness  and  relia- 
bility in  operation.  It  can  be  made  in 
large  sizes  operating  with  50,000  volts 
and  upward,  as  well  as  in  the  smaller 
sizes  such  as  are  used  in  the  ordinary 
home  radio  receiving  sets. 

Tubes  Were  Soft 

Prior  to  Dr.  Langmuir's  invention  radio 
and  X-ray  tubes  were  of  what  is  now 
known  as  the  soft  variety,  that  is  they 
glowed  and  acted  erratically  and  unre- 
liably except  when  used  on  exceedingly 
low  voltages.  Dr.  Langmuir's  invention, 
by  removing  this  severe  voltage  restric- 
tion, has  made  possible  practical  radio 
as  we  know  it  today. 

The  patent  application  has  had  an 
eventful  career.  Following  his  invention 
of  the  tube  in  1912,  Dr.  Langmuir  spent 
months  in  thoroughly  testing  the  inven- 
tion. He  filed  his  application  in  the 
patent  office  in  Washington  in  1913  and 
made  the  invention  known  to  the  world 
by  papers  read  before  scientific  societies 
and  by  descriptions  of  the  tube  in  scien- 
tific and  popular  publications.  The  tubes 
were  used  for  radio  work  by  the  French 
army  early  in  the  war  and  were  soon  in 
regular  use  in  radio  and  X-ray  work  in 
this  country. 

The  patent  application,  however,  did 
not  enjoy  such  immediate  success.  The 
Patent  Office  Examiner  passed  the  appli- 
cation for  issue  in  1916,  but  this  action 
was  revoked  before  the  patent  was 
issued  in  order  to  permit  another  person 
who  had  in  the  meantime  applied  for  a 
patent  on  this  invention  to  contest  Dr. 
Langmuir's  right  to  a  patent  in  what  is 
called  an  interference  proceeding. 

On  the  declaration  of  the  interference 
Dr.  Langmuir's  opponent  attempted 
to  show  that  the  invention  was  not  pa- 
tentable. On  account  of  the  unusual 
importance  of  the  invention  the  Patent 
Office  departed  from  its  usual  practice 
and  permitted  elaborate  testimony  to  be 
taken  on  the  question  of  patentability, 
including  even  testimony,  taken  in 
England,  on  behalf  of  Langmuir's  oppon- 
ent, a  world  famous  British  scientist. 

Held  Up  By  War 

After  the  United  States  went  into  the 
war  the  Secretary  of  the  Navy  requested 
the  Commissioner  of  Patents  to  suspend 
proceedings  because  the  full  time  of  both 
parties  was  required  upon  war  work  of 
great  importance  to  the  Government. 
After  the  war  testimony  was  resumed, 
(Continued  on  page  69) 


The  Magazine  of  the  Hour     £^[^65 


Hear  ALL  the  Music 

isoith  the  Bradley*  Amplifier 

THE  delicate  variations  and  shadings  of 
instrumental  music  and  the  exquisite 
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Amplifier.  It  matters  not  whether  you  own 
a  factory -built  set  or  a  home -built  re- 
ceiver, either  will  be  improved  by  using 
the  Bradley-Amplifier. 

Bradleyunit  resistors,  that  are  impervious 
to  moisture  and  unaffected  by  atmospheric 
changes,  take  the  place  of  the  audio-fre- 
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There  is  no  distortion  and  no  loss  of  low 
or  high  frequencies.  All  tones  are  repro- 
duced with  equal  facility.  As  a  result,  the 
low  notes  of  the  piano  are  greatly  improved 
and  the  high  notes  are  not  choked  or  dis- 
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duces a  marked  improvement  in  tone 
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Ask  your  dealer  for  the  Bradley- Amplifier 
today,  and  substitute  it  for  your  present 
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Resistance  coupled  amplifiers  are  acknowl- 
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66 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


Corrected  List  of  Broadcasting  Stations 


KDKA  Westinghouee  Electric  i  M>i.  Co East  Pittsburgh,  Pa.  309 

KDLR  Radio  Electric  Co Devils  Lake,  N.  D.  231 

KDPM  Westinghouse  Electric  A  Mfg.  Co Cleveland,  Ohio  270 

KDYL  NewhouBe  Hotel Salt  Lake  City,  Utah  250 

KDZB  Frank  E.  Siefert Bakersfield,  CaUf.  240 

KDZI  Electric  Supply  Co Wenatchee,  Wash.  360 

KFAB  Nebraska  Buick  Auto  Co.,  13th  4  Que  St« Lincoln,  Nebr.  341 

KFAD  McArthur  Bros.  Mercantile  Co Phoenix,  Ariz.  273 

KFAE  State  CoUege  ol  Washington PuUman,  Wash.  348 

KFAJ  University  of  Colorado Boulder,  Colo.  360 

KFAU  Boise  High  School Boise.  Idaho  271 

KFAW  The  Radio  Den  (W.  B.  Ashford) Santa  Ana.  Calif.  280 

KFBB  F.  A.  Buttrey  4  Co Havre.  Mont.  360 

KFBC  W.  K.  AzbUl San  Diego,  Calif.  278 

KFBC  First  Presbyterian  Church Tacoma,  Wash.  250 

KFBK  Kimball-Upson  Co Sacramento,  Calif.  283 

KFBL  LeeseBros Everett,  Wash.  224 

KFBS  School  District  No.  One Trinidad,  Colorado  238 

KFBU  Bishop  N.  S.  Thomas Laramie.  Wyo.  270 

KFCB  Nielson  Radio  Supply  Co Phoenii,  Ariz.  238 

KFCF  Frank  A.  Moore Walla  Walla,  Wash.  256 

KFCZ  Omaha  Central  High  School Omaha.  Nebr.  258 

KFDD  St.  Michaels  Cathedral Boise,  Idaho  252 

KFDH  University  of  Arizona Tucson,  Ariz .  368 

KFDJ  Oregon  Agricultural  CoUege Corvallis.  Ore.  254 

KFDM  Magnolia  Petroleum  Co Beaumont.  Texas  315 

KFDX  First  Baptist  Church Shreveport,  La.  360 

KFDY  South  Dakota  State  College Brookings,  S.  Dak.  360 

KFDZ  Harry  O.  Iverson Minneapolis,  Minn.  231 

KFEC  Meier  &  Frank  Co '. Portland,  Oreg.  248 

KFEK  Augsbury  Seminary Minneapolis,  Minn.  261 

KFEL  Winner  Radio  Corp Denver,  Colo.  254 

KFEQ  J.  L.  Scroggin Oak.  Nebr.  268 

KFE  Y  Bunker  Hill  &  Sullivan  Mining  and  Concentrating  Co Kellogg,  Idaho  233 

KFFP  First    Baptist    Church Moberly.    Mo.  260 

KFFV  Graceland    College , Lamoni.    Iowa  280 

KFGB  Heidbreder  Radio  Supply  Co. Utica,  Neb.  224 

KFGC  Louisiana  State  University Baton  Rouge,  La.  254 

KFGD  Chickaaha  Radio  4  Electric  Co Chickasha,  Okla.  248 

KFGH  Leland  Stanford  University Stanford  University,  Calif.  273 

KFGS  Crary  Hardware  Co Boone,  Iowa  226 

KFHA  Western  State  College  of  Colorado Gunnison,  Colo.  252 

KFHH  Ambrose  A.  McCue Neah  Bay,  Wash.  261 

KFHL  Penn  CoUege Oskaloosa,  Iowa  240 

KFI  E.  C.  Anthony.  Inc Los  Angeles.  Calif.  468 

KFIF  Benson  Polytechnic  Institute Portland.  Oreg.  248 

KFIO  North  Central  High  School Spokane.  Wash.  252 

KFIQ  First  Methodist  Church Yakima.  Wash.  242 

KFIU  Alaska  Electric  Light  &  Power  Co Juneau,  Alaska  226 

KFIZ  Daily  Commonwealth Fond  du  Lac,  Wis.  273 

KFJB  Marshall  Electrical  Co Marshalltown.  Iowa  248 

K.FJC  R.  B.  Fegan  (Episcopal  Church) Junction  City.  Kansas  219 

KFJF  National  Radio  Manufacturing  Co Oklahoma  City.  Okla.  252 

KFJI  Liberty  Theatre  (E.  E.  Marsh) Astoria,  Oreg.  252 

KFJL  Hardsacg  Manufacturing  Co Ottumwa.Iowa  242 

KFJM  University  of  North  Dakota Grand  Forks.  N.  Dak.  280 

KFJR  Ashley  C.  Dixon  4  Son Portland.   Oreg.  258 

KFJX  Iowa  State  Teacher's  College Cedar  Falls.  Iowa  280 

KFJ Y  Tunwall    Radio    Co Fort    Dodge,    Iowa  246 

KFJZ  Southwest  Bap.  Theo.  Seminary Fort  Worth,  Texas  254 

KFKA  Colorado  State  Teachers  College Greeley,  Colo.  273 

KFKQ  Conway  Radio  Laboratories  (Ben  H.  Woodruff) Conway,  Ark.  250 

KFKU  The  University  of  Kansas Lawrence,  KanB.  275 

KFKX  Westinehouse  Electric  4  Manufacturing  Co Hastings,  Nebr.  288 

KFLD  Paul  E.  Greenlaw Franklinton,  La.  234 

KFLR  University  of  New  Mexico Albuquerque.  New  Mexico  254 

KFLU  Rio  Grande  Radio  Supply  House San  Benito,  Texas  236 

KFLV  Rev.  A.  T.  Frykman Rockford,  111.  229 

KFLX  George  Roy  Clough Galveston.  Texas  240 

KFLZ  Atlantic  Automobile  Co Atlantic,  la.  273 

KFMB  Christian  Churches Little    Rock.   Arl.  254 

KFMQ  University  of  Arkansas Fayetteville,  Ark.  299 

KFMR  Morningside  CoUege .  Sioux  City.  Iowa  261 

KFMW  M.  G.  Sateren Houghton,  Mich.  266 

KFMX  Carleton  College Northfield.  Minn.  336 

K.FNF  Henry  Field  Seed  Co Shenandoah,  Iowa  266 

KFNG  Wooten's  RadioShop Coldwater,  Miss.  254 

KFNV  L.  A.  Drake  Battery  and  Radio  Supply  Shop Santa  Rosa.  Calif.  234 

KFOA  Rhodes  Department  Store Seattle.  Wash.  454 

KFOJ  Moberly  High  School Moberly.  Mo.  242 

KFON  Echophone  Radio  Shop Long  Beach.  Calif.  234 

KFOO  Latter  Day  Saints' University Salt  Lake  City,  Utah  261 

KFOP  Rohrer  Elec.  Co Marshfield.  Ore.  240 

KFOR  David  City  Tire  4  Electric  Co David  City.  Nebraska  226 

KFOT  College  Hill  Radio  Club Wichita.  Kansas  231 

KFOX  Board  of  Education, Technical  High  School Omaha.  Nebraska  248 

KFOY  Beacon  Radio  Service St.  Paul,  Minn.  226 

KFPG  Garretson  and  Dennis Los  Angeles,  CaUf .  238 

KFPL  C.  C.  Baiter Dublin,  Texas  242 

KFPM  The  New  Furniture  Co GreenviUe.  Texas  242 

KFPR  Los  Angeles  County  Forestry  Dept Los  Angeles  Calif.  231 

KFPT  Cape  *  Johnson Salt  Lake  City.  Utah  286 

KFPW  St.  Johns  M.  E.  Church Carterville,  Mo.  268 

KFPY  Symons   Investment   Co Spokane.   Wash.  283 

KFQA  The   Principia St.    Louis.    Mo.  264 

KFQB  The  Searchlight  Publishing  Co Fort  Worth.  Texas  221 

KFQC  Kidd  Brothers  Radio  Shop Taft.  Calif.  258 

KFQH  Radio  Service  Co Burlingame,  Calif.  231 

KFQP  G.  S.  Carson.  Jr Iowa  City.  la.  284 

KFQT  Texas  National  Guard Dennison    Texas  252 

KFQU  W.  Riker Holy  City.  Calif.  253 

KFQW  C.  F.  Knierim North  Bend.  Wash.  248 

KFQZ  Taft  Products  Co Hollywood.  Calif.  240 

KFRC  City  of  Paris  Dry  Goods  Co San  Francisco   Calif.  268 

KFRM  James  P.  Boland,  1st  Lt.,  U.  S.  Army Ft    Sill    Okla  242 

KFRU  Stephens  College Columbia,  Mo.  500 

KFRW  United  Churches  Of  Olympia Olympia.  Wash.  220 

KFRX  J.  Gordon  Klemgard PuUman    Wash  217 

KFRZ  The  Electric  Shop Hartington,  Neb.  222 

KFSG  Angelus  Temple Los  Angeles.  Calif.  272 

KFUJ  Hopper  Plumbing  and  Heating  Co Breckenridge,  Minn.  242 

KFUL  Thomas  Goggan  A  Bros.  Music  Co Galveston  Texas  258 

KFUM  W.  D.  Pyle Colorado  Springs.  Colo.  242 

KFUO  Concordia  Seminary .-: St.  Louis.  Mo.  549 

KFUP  Fitzsimmons  General  Hospital Denver.  Colo.  234 

KFUQ  Julius  Brunton  and  Sons  Co . San  Francisco  Calif  234 

KFUR  H.  W.  Peery  and  C.  Redfield. Ogden' Utah  224 

KFUS  Louis  L.  Sherman Oakland.' Calif.  233 

KFUU  Colburn  Radio  Labs San  Leandro.  Calif.  231 

KFVD  McWhinnie  Electric  Co San  Pedro,  Calif.  202 

KFVE  Film  Corporation  of  America St.  Louis,  Mo.  245 

KFVF  Clarence  B.Juneau HoUywood.  Calif.  208 

KFVG  First  M.  E  Church Independence.  Kansas  236 

KFVH  Whan  Radio  Shop  (Herbert  Whan) Manhattan.  Kansas  218 

KFVI  Headquarters  Troop.  56th    Cavalry Houston    Texas  248 

KFVN  Carl  E.    Bagley Welcome  '  Minn  227 

KFVO  F.M.Henry. KirksviUe,    Mo.  226 

KFVR  Moonlight  Ranch Route  6,  Denver,  Colo.  246 

KFVS  Cape  Girardeau  Battery  Station Cape  Girardeau    Mo  224 

FEXif  Radio  Supply  Co Albuquerque.  N.  M.  250 

KFVZ  Glad  Tidings  Tabernacle San  Francisco    Calif  234 

K™A  ~<,wnin£  Bto'-  Co Ogden,  Utah  214 

5™5  ^M?"4,B.TM ' Hollywood,  Calif.  252 

SSKS  £-.?■  W;" Upland.  Calif.  211 

KFWV  Wilbur   Jerman 385    58th   St.  S.,  Portland,    Ore.  212 

KFWF  St.  Louis  Truth  Center St.  Louis,  Mo.  214 


K.FWH      F.  Wellington  Morse.  Jr Chico,  Calif.  254 

KFWI        Radio  Entertainments,   Inc South   San   Francisco,   CaUf.  220 

KFWM     Oakland  Educational  Society Oakland.  Calif.  224 

KFWO      Lawrence  Mott Avalon,  Calif.  211 

KFWP      Rio  Grande  Radio  Supply  House Brownsville,  Texas  214 

KFWU      Louisiana    CoUege PineviUe,    La.  238 

KFXB       Bertram  O.  Heller , Big  Bear  Lake,  Calif.  203 

KFXC       Santa   Maria  Valley  Railroad   Co Santa   Maria,   Calif.  210 

KFXD       L.    H.    Strong Logan.  Utah  205 

KFXE      Electrical  Research  &  Mfg.  Co Waterloo.  Iowa  236 

KFXF       Pize's    Peak  Broadcasting    Co Colorado    Springs,    Colo.  250 

KFXH      Bledsoe  Radio  Company El  Paso,  Teias  242 

KFXJ  Mountain  States  Radio  Distributors,  Inc.  (Portable  station)  Denver,  Colorado  216 

KFXM      Neches  Electric  Co Beaumont.  Texas  227 

KFXY       Mary  M.  Costigan Flagstaff,  Ariz.  205 

KFYF        Carl's  Radio  Den Oxnard,  Calif.  205 

KFYJ        Houston  Chronicle  Publishing  Co Houston,  Texas  238 

KGB         Tacoma  Daily  Ledger , Tacoma,    Wash.  252 

KGO         General  Electric  Co Oakland,  Calif.  361 

KGU         Marion    A.    Mulrony Honolulu,    Hawaii,    Waikiki   Beach  370 

KGW         Portland  Morning  Oregonian Portland,  Oreg.  491 

KG Y         St.  Martins  College  (Reb.  Sebastian  Ruth) Lacy,  Wash.  253 

KHJ          Times-Mirror  Co Los  Angeles.  Calif.  405 

KHQ         Louis  Wasmer Seattle,  Wash.  273 

KJR           Northwest  Radio  Service  Co Seattle,  Wash.  384 

KJS           Bible  Institute  of  Los  Angeles.  Inc Los  Angeles,  Calif.  293 

KI.DS  Reorganized  Church  of  Jesus  Christ  of  Latter  Day  Saints,  Independence,  Mo.  441 

KLS           Warner  Brothers  Radio  Supplies  Co Oakland,  Calif.  242 

KLX           Tribune   Publishing   Co Oakland,   Calif.  508 

KLZ           Reynolds  Radio  Co Denver,  Colo.  283 

KMJ          San  Joaquin  Light  4  Power  Corp Fresno,  CaUf.  243 

KMO         Love  Electric  Co Tacoma,  Wash.  250 

KNX         Los  Angeles  Evening  Express Los  Angeles,  Calif .  337 

KOA          General  Electrio  Co Denver.  Colo.  323 

KOB  New  Mexico  College  of  Agriculture  4  Mechanic  Arts.  State  College.  N.  Mex.  348 

KOIL         Monarch  Manufacturing  Co Council  Bluffs,  Iowa  278 

KOP          Detroit  Police  Department Detroit,  Mich.  286 

KPO          Hale  Bros San  Francisco,  Calif.  42S 

KPPC        Pasadena  Presbyterian  Church Pasadena,  CaUf.  229 

KPRC       Houston    Post-Dispatch Houston,    Texas  270 

KQP          H.  B.  Read Portland,  Ore.  21Z 

KQV          Doubleday-Hill   Electric   Co Pittsburgh,    Pa.  270 

KQW        Charles  D.  Herrold San  Jose,  Calif.  226 

KRE          Berkeley  Daily  Gazette Berkeley,  CaUf.  275 

KSAC        Kansas  State  Agricultural  CoUege Manhattan,  Kans.  34J 

KSD          Post  Dispatch  (Pulitzer  Pub.  Co.) St.  Louis,  Mo.  545 

KSL           Radio  Service  Corp.  of  Utah Salt  Lake  City,  Utah  299 

KSO            A.  A.  Berry  Seed  Co Clarinda.  Iowa  242 

KTAB       Tenth  Ave.  Baptist  Church Oakland,  Calif.  216 

KTBR       Brown's  Radio  Shop Portland.  Oregon  263 

KTCL       American  Radio  Telephone  Co.,  Inc Seattle.  Wash.  306 

KTHS       New  Arlington  Hotel  Co Hot  Springs.  Ark.  375 

N.  Baker Muscatine,  Iowa  256 

KTW         FirBt  Presbyterian  Church Seattle,  Wash.  455 

KUO         Examiner  Printing  Co San  Francisco,  CaUf.  246 

KUOM      State  University  of  Montana Missoula,  Montana  244 

KUT          University  of  Texas Austin,  Texas  231 

KWC         Portable  Wireless  Telephone  Co Stockton,  Calif.  248 

KWKC     Wilson  Duncan  Studios Kansas  City,  Mo.  236 

KWWG    City  of  Brownsville BrownaviUe,  Texas  278 

KYO         Electric   Shop Honolulu,  Hawaii  270 

KYW        Westinghouse  Electric  &  Mfg.  Co Chicago,  111.  535 

KZM         Preson  D.  AUen Oakland,  CaUf.  242 

WAAB      Valdemar  Jensen New  Orleans,  La.  263 

WAAC      Tulane  University New  Orleans,  La.  275 

WAAD      Ohio  Mechanics  Institute Cincinnati,  Ohio  248 

WAAF      Chicago    Daily    Drovers   Journal Chicago,    111.  286 

WAAM     I.  R.  Nelson  Co Newark,  N.  J.  263 

WAAW     Omaha  Grain  Exchange Omaha,  Nebr.  285 

WABC      Asheville  Battery  Co..  Inc Asheville,  N.  C.  254 

WABI        1st  UniversalUt  Church Bangor.  Me.  240 

WABL       Connecticut    Agricultural    College Sorrs,    Conn.  283 

WABO       Lake  Avenue  Baptist  Church Rochester,  N.  Y.  283 

WABQ      Haverford  CoUege.  Radio  Club Haverford.  Pa.  261 

WABR      Scott  High  School.  N.  W.  B.  Foley Toledo.  Ohio  270 

WABW     College  of  Wooster Wooster.  Ohio  234 

WABX      Henry  B.Joy Mt.  Clemens,  Mich.  270 

WABY      John  Magaldi.  Jr PhUadelphia,  Pa.  242 

WABZ      Coliseum  Place  Baptist  Church New  Orleans,  La.  263 

WADC      AUen  T.  Simmons  (Allen  Theatre) Akron,  Ohio  258 

WAFD      Albert  B.  Parfet  Co Port  Huron.  Mich.  275 

WAHG     A.  H.  Grebe  4  Co Richmond  HU1,  N.  Y.  31S 

WAMD     Hubbard  4  Co Minneapolis,  Minn.  244 

WAPI         Alabama   Polytechnic   Institute Auburn.   Ala.  248 

WBAA      Purdue  University W.  Lafayette.  Ind.  283 

WBAC      Clemson  Agric.  CoUege Clemaon  College,  8.  C.  331 

WBAH      The  Dayton  Co Minneapolis,  Minn.  417 

WBAK      Pennsylvania  State  Police Harrisburg,  Pa.  275 

WBAO      James   Millikan   University Decatur.  III.  360 

WBAP       Wortham-Carter  Publishing  (Star  Telegram) Fort  Worth,  Texas  476 

WBAV       Erner  4   Hopkins   Co Columbus,  Ohio  292 

WBAX      John  H.  Stenger.  Jr Wilkes-Barre.  Pa.  254 

WBAY      Western  Electric  Co New  York,  N.  Y.  492 

WBBG      Irving  Vermilya Mattapoisett,  Mass.  248 

WBBL       Grace  Covenant  Presbyterian  Church Richmond,  Va.  253 

WBBM     Atlass   Investment   Co Chicago.    IU.  226 

WBBN      Blake.  A.  B •. Wilmington,  N.  C.  27S 

WBBP       Petoskey  High  School Petoskey,  Mich.  246 

WBBR      People's  Pulpit  Assoc RossviUe.  N.  Y.  273 

WBBS       First  Baptist  Church New  Orleans.  La.  252 

WBBU      Jenks  Motor  Sales  Co Monmouth,  111.  224 

WBBX      Ruflner  Junior  High  School Norfolk.  Va.  222 

WBBY      Washington   Light   Infantry   Co.   "B"    118th   Inf Charleston,   S.   C.  268 

WBBZ       C.    L.    Carrel,    (portable) Chicago,   111.  216 

WBCN      Foster  4  McDonneU Chicago.  IU.  500 

WBDC       Baxter  Laundry  Co Grand  Rapids.  Mich  256 

WBES       Bliss  Electrical  School Takoma  Park.  Md.  222 

WBGA      Jones  Elec.  4  Radio  Mfg.  Co Baltimore.  Md.  254 

WBOQ      A.  H.  Grebe  4  Co..  Inc Richmond  Hill,  N.  Y.  23S 

WBR          Pennsylvania  State   PoUce Butler.   Pa.  286 

WBRC      Bell  Radio  Corporation Birmingham.  Ala.  248 

WBRE       Baltimore  Radio  Exchange Wilkes-Barre.  Pa.  231 

WBS          D.  W.  Mav,  Inc Newark,  N.  J.  252 

WBT          Charlotte  Chamber  of  Commerce Charlotte,  N.  C.  250 

WBZ          Westinehouse  Electric  4  Mfg.  Co Springfield.  Mass.  333 

WBZA      Westinghouse  Electric  4  Mfg.  Co Hotel  Brunswick,  Boston,  Mass.  242 

WCAD       St.   Lawrence   University Canton,   N.  Y.  280 

WC  AE       Kaufmann  4  Baer  Co.  and  The  Pittsburgh  Press Pittsburgh  .Pa.  461 

WCAH      Entrekin  Electric  Co Columbus,  Ohio  286 

WCAJ        Nebraska  Wesleyan  University University  Place.  Nebr.  283 

WCAL      St.  Olaf  CoUege Northfield.  Minn.  336 

WCAO      Sanders  4  Stayman  Co Baltimore.  Md.  275 

WCAP       Chesapeake  4  Potomac  Telephone  Co Washington,  D.  C.  468 

WCAR      Alamo  Radio  Electric  Co San  Antonio.  Texas  263 

WCAS       W.  H.  Dunwoody  Industrial  Institute Minneapolis.  Minn.  280 

WCAT      State  College  of  Mines Rapid  City,  S.  Dak.  240 

WCAU      Durham  4  Co Philadelphia,  Pa.  278 

WCAX      University  of   Vermont Burlington.   Vt.  250 

WCAZ       Carthage     College Carthago,     IU.  246 

WCBA       Charles  W.  Heibachm Allentown.  P».  280 

WCBD      Wilbur    C.    Voliva - Zion,    IU.  344 

WCBE       Uhalt  Radio  Co New  Orleans.  La.  263 

WCBF      Paul  J.  Miller Pittsburgh,  Pa.  236 

WCBG      Howard  S.  Williams  (Portable) Pascagoula,  Miss.  268 

WCBH      University   of   Mississippi Oxford.    Misb.  242 

WCBM     Charles  Swan .-...- ; . .  .Baltimore.  Md.  229 


RADIO  AGE  for  December,  1925 


Here's  British  View  of 
Broadcasting 

(Continued  from  page  64) 

at  a  very  late  hour  once  a  month.  In 
exchange,  its  nearby  listeners  would 
be  having  the  opportunity  of  tuning  in 
other  distant  stations  during  the  remain- 
der of  the  month  during  their  special 
hours. 

The  B.  B.  C.  have  often  said  that  they 
wish  to  study  the  crystal  user,  and  they 
are  naturally  justified  in  looking  at  broad- 
casting from  this  angle.  A  crystal  user 
pays  10  shillings  for  his  license  just  as 
does  the  multivalve  user.  But  what  the 
B.  B.  C.  seem  to  forget  is  that  the 
multivalve  user  does  much  more  for  the 
wireless  trade  in  general  than  his  crystal 
user  brother,  and  most  of  the  B.  B.  C. 
shareholders  are  directly  or  indirectly 
interested  in  the  development  of  wireless 
trade.  We  are  all  interested  in  the  re- 
lief of  unemployment  in  this  country  to 
which  this  trade  contributes  its  share. 
There  is  then,  no  reason  why  the  mul- 
tivalve users  should  not  be  especially 
studied,  and  the  introduction  of  these 
silent  nights  and  special  transmissions 
would  be  a  great  boon  to  them.  I  do 
not  want  to  accuse  the  B.  B.  C.  of  doing 
nothing  to  help  them,  I  am  pleased  to 
say  that  I  recently  heard  that  once  a 
week  at  the  closing  down  of  every  station, 
the  announcer  will  specially  give  out  the 
name  of  the  B.  B.  C.  station  which 
continues  transmitting  for  a  half  hour 
on  that  day.  Things  are  being  done  and 
we  know  that  the  B.  B.  C.  is  alive  to  all 
these  problems,  but  a  lot  more  should 
be  done  and  can  be  done,  and  we, 
the  leading  nation  in  Europe  in  these 
matters,  should  take  the  initiative.  We 
have  powerful  wireless  bodies  in  this 
country,  and  the  Conference  can  be 
called.  Let  it  then  be  called  without 
delay. 


Class  B  Interference  Not  Bad, 
Says  Canadian  Fan 

THE  OTHER  day,  Secretary  of  Com- 
merce Hoover  had  a  shock — not  from 
his  radio  set,  but  due  to  a  commendatory 
letter  from  a  radio  fan.  Instead  of  being 
a  complaint  about  interference,  the  letter 
stated  that  there  was  little  difficulty  in 
separating  the  Class  B  stations,  except 
two  stations  on  one  wave  length  and  three 
on  another. 

The  writer,  John  Young,  of  Little 
Current,  Ontario,  believes  the  present 
arrangement  of  stations  is  very  satis- 
factory and  that  much  of  the  reported 
interference  comes  from  owners  of  poor 
or  badly  operated  receivers. 

His  letter  to  Secretary  Hoover,  for 
publication,  follows  in  part: 

"There  has  been  a  lot  of  discussion  in 
the  radio  columns  of  the  press  lately 
about  interference  of  Class  B  stations  on 
account  of  your  recent  separation  of  these 
broadcasters  by  ten  kilocycles.  For  your 
information  and  in  view  of  the  approach- 
ing conference,  I  should  like  to  give  you 
my  experience  as  an  operator  of  all  types 
of  receiving  sets  for  several  years. 

"In  my  opinion  the  present  arrange- 
ment of  stations  is  very  satisfactory,  and 
much  of  this  interference  talk  arises  from 
owners  of  poor  receivers,  badly  tuned  and 


from    a    misconception    of    what    causes 
heterodyning  and  cross-talk." 

While  experimenting  one  night  re- 
cently, Mr.  Young  decided  to  log  a 
number  of  the  higher  powered  U.  S. 
stations,  noting  any  interference.  This 
he  did,  listing  36  stations  with  good, 
loud  speaker  volume  in  five  hours.  His 
only  complaint  is  that  something  ought 
to  be  done  to  get  WGR,  Buffalo,  and 
WSMB,  New  Orleans,  to  split  time  on  the 
319     meter     wave,     and      to     persuade 


The  Magazine  of  the  Houf  67 

stations  WNYC,  New  York;  WHO,  Des 
Moines;  and  WOAW,  Omaha,  to  divide 
time  three  ways  on  their  wave  length  of 
526  meters. 

"Outside  of  that,"  he  reports,  "Class  B 
stations  are  O.K. 

"As  for  Class  A  stations,"  he  continues, 
"nothing  can  be  done.  There  are  so  many 
on  the  same  wave  length  that  serious 
heterodyning  is  bound  to  occur,"  he  con- 
cludes, thanking  the  Secretary  for  his 
interest  in  radio. 


ERLAs  New  Audio 

Gives  MaivelousTone  Coive 


Exacting  laboratory Jtests  show 
that  no  other  audk>2gives^such 
perfect  reproduction.  Note  how 
uniformly  and  evenly  all  notes  are 
amplified  at  frequencies  from  32 
to  10,000  cycles. 


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Note  the  quadruple  core  sur- 
rounding the  coil,  forming  an 
almost  perfect  path  for  the  flux 
within  the  coil.  The  core  is  a 
special  grade  of  laminated  silicon 
steel  that  provides  highest 
permeability  and  lowest  hys- 
teresis loss,  with  consequent 
maximum  conductivity  in  the 
magnetic  circuit  of  the  trans- 
former. Price  $10.  West  of 
Rocky  Mountains,  S10.50. 


AN  amazing  improvement 
has  been  made  in  audio 
amplification.  A  new  trans- 
former— the  Erla  Concert 
Grand — gives  results  far  su- 
perior to  any  other  system  of 
amplification. 

Amazing  Improvement 

Ordinary  designs  permit  too 
much     leakage     to     amplify 
properly  at  low  frequencies. 
So   we   use  the   "quadriform 
type,"    heretofore    unknown 
in   radio   work.     In   this   de- 
sign    magnetic     leakage     is 
practically  eliminated  by  pro- 
viding twice  as  many  paths 
for    the    magnetic    field    and 
by   a    better    distribution   of 
the   core    metal    around    the 
copper  wire  coils.    Each  of  the  four  core 
units     are     complete     magnetic    circuits 
within     themselves     without     breaks    or 
joints  to  the   main  central  core,*and  it 
will  also  be  noticed  that  the  central  core 
section  has  a  far  greater  area  than  con- 
ventional core  types.    The  large  area  thus 
obtained  reduces  the  effect  of  the  direct 
"B"    battery    current    on    the    pulsating 
voice  currents  and  eliminates  a  cause  of 
distortion  common  to  transformers  using 
smaller  core  sections. 

The  Concert  Grand  saves  you  money, 
too.     Resistance  coupling  depends  solely 

JrT\  Brr\  *  Irr: 

*    Tested  and  Approved  by  RADIO  AGE    * 


One-piece  drawn  steel  shell  provides  perfect 
magnetic  shielding.  Finished  in  black 
crystalline  lacquer  and  attractive  in 
appearance. 

upon  the  tubes  for  amplifica- 
tion. Consequently  they  must 
be  operated  at  maximum  for 
efficiency,  requiring  more  "A" 
battery  current  and  higher 
plate  voltage — 135  to  150 
volts.  Filaments  wear  out 
more  rapidly  as  a  result  and 
battery  life  is  more  than  cut 
in  half.  The  higher  initial 
cost  of  Concert  Grand  am- 
plification is  therefore  saved 
many  times  over,  not  only  in 
improved  performance  but 
also  in  lowered  upkeep  cost. 


Booklet  Sent  FREE 

Get  the  Audio  Grand  at  your 
dealer's  today.  See  what  a  tremendous 
difference  it  will  make  in  your  set.  If 
you  wish  to  return  the  coupon,  we  will 
send  you  a  new  booklet  giving  the  latest 
information  on  audio  frequency  ampli- 
fication 

Electrical  Research  Laboratories 
Chicago,  U.  S.  A. 

1 


I 

l    Electrical  Research  Laboratories, 

I    2500  Cottage  Grove  Ave.,  Depi.  0-C,  Chicago 


Send  me  information  about  the  Erla  Concert  Grand 
Audio.  Abo  latest  developments  on  audio  frequency 
amplification. 


.County State. 


_l 


68 


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RADIO  AGE  for  December,  1925 

James  P.  Boland Ft.  Benj.  Harrison,  Ind.  266 

First  Baptist  Church * Nashville,  Tenn.  236 

C.  H.  Mesater Providence,  R.  I.  246 

Clark  University,  Collegiate  Dept Worcester,  Mass.  238 

Radio  Shop  of  Newark  (Herman  Lubinsky) Newark,  N.  J.  233 

Wash  burn- Crosby  Co Twin  Cities,  Minn.  416 

C.  E.  Whitmore Camp  Lake.  Wise.  231 

H.    M.    Couch Joliet,    111.  214 

Henry  P.  Rines Portland,  Maine  256 

Free  Press  and  Jewett  Radio  &  Phonograph  Co Detroit,  Mich.  517 

Dad'B    Auto    Accessories,    lnc Nashville,  Tenn.  226 

Tampa    Daily    Times Tampa,    Fla.  365 

Kansas  City  Star Kansas  City,  Mo.  365 

J.  Laurence  Martin Amarillo,  Texas  263 

Lit    Brothers Philadelphia,     Pa.  393 

Radio  Equipment  Corp Fargo,  N.  Dak.  244 

Fred  Ray    Columbus,  Ga.  236 

A.  H.  Waite  &  Co.,  Inc Taunton,  Mass.  229 

Kirk,  Johnson  &  Co Lancaster,  Pa.  258 

Herman     Edwin     Burns Martinsburg,     W.     Va.  268 

Gilhara-Schoen    Elec.    Co Atlanta,    Ga.  278 

Richardson  Wayland  Electric  Corp Roanoke,  Va.  229 

M.  F.  Broz Cleveland,  Ohio  722 

Wisconsin  Dept.  of  Markets Stevens  Point,  Wis.  278 

Electric  Light  &  Power  Co. Bangor,  Me.  252 

Rollins  College,  Ino Winter  Park,  Fla.  240 

Morton   Radio  Supply   Co Salem,    N.   J.  234 

Tremont  Temple  Baptist  Church Boston,  Mass.  256 

The  Strand  Theatre Fort   Wayne.   Ind.  258 

North  Shore  Congregational  Church Chicago.  111.  258 

Boy  Scouts,  City  Hall Kingstown.  N.  Y.  233 

Dartmouth  College Hanover.  N.  H.  256 

Chattanooga  Radio  Co.,  Inc Chattanooga,  Tenn.  256 

Dutee  Wilcox  Flint,  Inc Cranston,  R.  I.  441 

J.    L.  Bush Tuscola,    111.  278 

F.    D.    Fallain Flint,    Mich.  250 

American  Telephone  &  Telegraph  Co New  York,  N.  Y.  485 

Hotel   Lassen Wichita,   Kans.  280 

Cornell    University Ithaca,     N.    Y.  286 

University  of  South  Dakota., Vermilion.  S.  Dak  283 

Borough  of  North  Plainfield  (W.  Gibson  Buttfield) .  .  North  Plainfield,  N.  J.  286 

Sbepard  Co Providence.  R.  1.  273 

Ohi     " 


The  Magazine  of  the  Hour 


State  University Columbus,  Ohio     293 


id  Rubber  Co Cleveland,  Ohi 

Davidson  Bros,  Co Sioux  City,  Iowa 

Benwood  Co St.    Louis,    Mo. 

Electric      Shop Highland      Park,      N.      J. 

Walter    Cecil    Bridges . Superior,    Wis. 

Electrical  Equipment  and  Service  Co Anderson,  Ind. 

Roy  W.  Walker ". .  . Cambridge,  Ohio 

Edgewater  Beach  Hotel,  Chicago  Evening  Post  Station.  ......  Chicago,  HI. 

Third  Avenue  Railway  Co New  York,  N.  Y. 

Grand  Rapids  Radio  Co Grand  Rapids,  Mich- 
Radio  Corporation  of  America Portable 

E.  B.  Pedicord New  Orleans.  La. 

The  Dayton  Coop.  Industrial  High  School Dayton,  Ohio 

Beloit     College Beloit,      Wis. 

The  Edison  Electric  Illuminating  Co Boston,  Mass. 

Robert   E.    Hughe3 Evanston,    111. 

All-American  Radio  Corporation Chicago.  Illinois 

St.  Louis  University St.  Louis.  Mo. 

Dallas   News   &   Dallas   Journal Dallas.   Tex. 

Times  Publishing  Co St.  Cloud.  Minn. 

University  of  Nebraska,  Department  of  Electrical  Engineering,  Lincoln,  Nebr. 

First  Baptist  Church Knoxville,  Tenn. 

Gethsemane  Baptist  Church Philadelphia,  Pa. 

Van  De  Walle  Music  and  Radio  Co Seymour.  Ind. 

The  Wm.  F.  Cable  Co Altoona,  Pa. 

Concourse  Radio  Corporation New  York,  N.  Y. 

fat.  John's  University Collegeville,  Minn. 

Wynne  Radio  Co Raleigh,  N.  C. 

Fifth  Inf.  Md.  Nat'l  Guard.  Bth  Reg.  Armory Baltimore.  Md. 

Ainsworth-Gates  Radio  Co Cincinnati,  Ohio 

Knox    CoUege Galesburg,    111. 

Strawbridge  and  Clothier Philadelphia.  Pa. 

Francis   K.   Bridgman Chicago.   HI. 

Robert  Morrisson  Lacey Brooklyn,  New  York 

G.  Pearson  Ward Springfield.  Mo. 

Earl   William   Lewis Moberly.   Mo. 

Lancaster  Electric  Supply  &.  Construction  Co Lancaster,  Pa. 

Youree  Hotel Snreveport,  La. 

South  Bend  Tribune South  Bend,  Ind. 

Harry  H.  Carman,  217  Bedell  St Freeport.  N.  Y. 

First  Baptist  Church Memphis,  Tenn. 

Fink  Furniture  Co Evansville,  Ind. 

Frank  S.   Megargee v._ Scranton,   Pa. 

Lawrence   Campbell Jv^ .^ Johnstown,    Pa. 

Thedore  N.  Saaty S. y  .' Providence,  R.  I. 

Stout  Institute .-  - .  - Menominee,  Wis. 

Marshfield  Broadcasting  Assn Marshfield,  Wis. 

Gimbel  Brothers New  York.  N.  Y. 

Florida  Cities  Finance  Co Fulford  By-The-Sea,  Florida 

University   of    Maine. Orono,    Mo. 

G.  H.  Phelps,  Inc .Detroit,  Mich. 

Coyne  Electrical  School Oak  Park,  111. 

G.  H.  Bowles  Developments Clearwater,  Fla. 

American  R.  &  R.  Co ; Medford  Hillside,  Mass. 

A.  H.  Grebe  &  Co.,  Inc.,  Portable Richmond  Hill,  N.  Y. 

The  Tribune Chicago.  HI. 

Federal  T.  and  T.  Co Buffalo,  N.  Y. 

General  Elec.  Co Schenectady,  N.  Y. 

University  of  Wisconsin Madison,  Wis. 

Marquette  University  and  Milwaukee  Journal Milwaukee.  Wis. 

University  of  Cincinnati Cincinnati,  Ohio 

Hafer  Supply  Co Joplin.  Mo. 

University  of  Rochester  (Eastman  School  of  Music) Rochester,  N.  Y. 

H.  Alvin  Simmons,  290  Flatbusb  Ave Brooklyn.  N.  Y. 

Seaside  House Atlantic  City,  N.  J. 

Courier-Journal  &  Louisville  Times Louisville,  Ky. 

Dr.  George  W.  Young Minneapolis.  Minn. 

Wilmington  Electrical  Specialty  Co ." Wilmington,  Del. 

Rensselaer  Polytechnic  Institute Troy.  N.  Y. 

Sweeney  School  Co Kansas  City,  Mo. 

C.  C.  Shaffer Qil  City.  Pa. 

Rev.  E.  P.  Graham Canton,  Ohio 

Chas.  W.   Howard Bellfontaine.  Ohio 

Beardsley  Specialty  Company Rock  Island.  Illinois 

John  S.  Skane Harrisburg,  Pa. 

Culver  Military  Academy Culver,  Ind. 

Lauer  Auto  Co ft.  Wayne.  Ind. 

Franklin  St.  Garage.  Inc. Ellsworth!  Me! 

James  H.  Slusser Logansport.  Ind. 

C.  L.  Carroll,  Portable  Station Chicago   111. 

First  Ave.  Methodist  Church St.  Petersburg,  Florida 

Johnstown    Automobile    Co Johnstown,    Pennsylvania 

St.  John's  M.E.  Church  South ■ Memphis,  Tenn. 

Scienti6c  Electric  &  Mfg.  Co..  3664  Vine  St Cincinnati.  Ohio 

Riviera  Theatre  and  Bing 's  Clothing Anderson   Ind 

D.  R.  Kienzle  . :    Philadelphia.  Pa.' 

St.  Norbert  s  College West  De  Pore.  Wis. 

Hickson  Electric  Co..  Inc Rochester,  N.  Y. 

The  Radio  Air  Service  Corp Cleveland   Ohio 

George  Schubert New  yOJ.k    j^    Y 

Bankers'  Life  Co x>es  Moines    la 

Wrigley  Building,  Chicago Deerfield.'  III! 

Howard  R.  Miller  Philadelphia  Pa. 

Chronicle    Publishing    Co Marion     Ind. 

Home  Electric  Co Burlington,  Iowa 

The  Capital- Times  Studio .  .  .  * Madison    Wis 

L.  M.  Tate  Post.  No.  29.  "Veterans  of  Foreign  Wars ...  St.  Petersburg   Florida 

St.  Paul's  Protestant  Episcopal  Church Elkins  Park    Pa 

Elite-Radio  Stores Now  Bedford    Mass 


3*9 
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Frederick  B.  Zitteli.  Jr FlushinH-   N   Y 

C-   L    Oarrell  (Portable;  Chicago    IU 

?eHS°  A™,!T Chicago.     111. 

F     M.    Schmidt, FariMi    1U. 

1  nurman  A.  Owings, Werton    W    Va 

New  Jersey  Ns.fl  Guard  Hdqs.  Co Elizabeth.  N.  J.' 

The  Electric  Farm Poynette.  Wis. 

r'^i  \D? Logansport.  Ind. 

ijrid-ljeaK  lnc Utica    N    Y 

Powell   Electric   Company    .       Montgomery.   Ala! 

Continental  Electric  Supply  Co Washington,  D.  C. 

Gimbel  Bros Philadelphia..  Pa. 

American  Electric  Co. Lincoln.  Nebr. 

Jackson  s  Radio  Engineering  Laboratories Waco  Texas 

?,°«o1JtD  w??°Wa Norfolk!  Nebr. 

Khf  9'dL.  White Greentown,  Iowa 

D.  M.  Perham Cedar  Rapids  Iowa 

The  Outlet  Co.  (J.  Samuels  &  Bro.) '.'...  Providence!  R.  I. 

Pittsburgh  Radio  Supply  House Pittsburgh,  Pa. 

Zenith  Radio  Co Mc.  Prospect.  111. 

L.  W.  McClurg. St.  Petersburg,  Fla. 

Hummer    r  urniture    Co LaSalle     111 

Interstate  Radio.  Inc '.'.'.'.'.'.'.'.'.'.Charlotte.  N.  C. 

Robert  S.  Johnson R.d  Bank,  New  Jersey 

E.  F.  Goodwin Ypsilanti,  Mich. 

Wm.  Gushard  Dry  Goods  Co Decatur    111 

St.  Johns  Ev.  Luth.  Church '_'[/_  .Sycamore.  111! 

Denison  University.  ...........    Granville.  Ohio 

Supreme  Lodge.  Loyal  Order  of  Moose Mooseheart,  IU. 

Jewett  Radio  &  Phonograph  Co.  and  Detroit  Free  Press     .  .    Pontiac    Mich 

Radio  Corp.  of  America New  York.  N.y! 

Radio  Corp.  of  America New  York  N  Y 

H  F.Paar .      ... .'.'.'.Cedar  Rapids',  Iowa 

SJS3;  h°£B  «JrMC?nt  gark> East  Providence.  R.  I. 

WK^FBroadcasting  Co Milwaukee.  Wis. 

Radio  Corp.  of  Porto  Rico gan  jUan  P  R 

Michigan  Agriculture  CoUege '.'.'.East  Lansing.  Mich! 

Laconia  Radio  Club Laconia,  N.  H. 

Sanders  Bros....  . Joiieti  Iu. 

£■  &  B;,£1<lctrl,S,.C° Webster,  Massachusetts 

Dutee  Wilcox  Flint. Cransten,  Rhode  Island 

C.  L.  Carrel,  Portable Chicago,  IU. 

Miss  Shirley  Kats New  York,  N.Y. 

Wky  Radio  Shop ••••••■ Oklahoma  City,  Okla. 

Cutting  &  Washington  Radio  Corp Minneapolis  Minn 

First  Christian  Church Tulslli  okla. 

Wm.  V.  Jordan LouisviUe.  Ky. 

Arthur  E.  Shilling Kalamazoo,  Mich. 

Putnam  Electnc  Co Greencastle.lnd. 

University  of  Minnesota Minneapolis   Minn. 

Wisconsin  State  Dept.  of  Markets [ !  Stevens  Point  Wis* 

Liberty  Magazine.  .    Chicago.  111. 

Sears.  Roebuck  & .Co Chicago,  IU. 

Lane  1  echnical  High  school Chicago   111. 

Crosloy  Mfg.  Co. ..............  . '.'.'.Cincinnati,  Ohio 

Missionary  fctociety  of  ot.  Paul  the  Apostle New  York  N  Y. 

J.  Edw.  Page  (Olive  B.  Meredith) '.'.'  Casenovia  '.n'  Y* 

Round  Hills  Radio  Corp Dartmouth.  Mass. 

Norton  Laboratories Lockport    N.  Y. 

M.  A.  Lesse  Optical  Co '  .'"Washington,  D.  C*. 

First  Baptish  Church Columbus,  Ohio 

Chicago  Daily  News Chicago,  IU. 

Kingshighway  Presbyterian  Church gt.  Louis"    Mo. 

Mercer    University Macon!    Ga. 

Trianon    BaU    Room. . . Chicago.    IU. 

Michigan  Broadcasting  Co Detroit.  Mich. 

Miami  Beach  Hotel Miami  Beach,  Fla. 

Commercial  Appeal Memphis    Tenn. 

Hotel  McAlpin  (Greenley  Square  Hotel  Co.) New  York  City 

Ainsworth-Gates  Radio  Co Cincinnati    O. 

Shepard  Stores. Boston,    Mass! 

University  of  Oklahoma Norman    Okla. 

Omaha  Central  High  School Omaha  Nebr. 

Witwnberg  College. Springfield.  Ohio 

r  irst  Christian  Church Butler    Mo. 

Lennig  Brothers  Co.  (Frederick  Lennig) PhUadelphia  Pa! 

Dakota  Radio  Apparatus  Co '.'.'.Yankton  S.  Dak! 

Peoples  *  Tel.  Co.. KnoxvUle.  Tenn. 

Dept.  of  Plant  and  Structures New  York  N  Y. 

Pago  Organ  Co ' Lima.  Ohio 

Midland  CoUege Fremont.  Nebr. 

ApoUo  Theatre  (Belvidere  Amusement  Co.) Belvidere,  HI. 

Southern  Equipment  Co San  Antonio,  Texas 

Vaughn  Conservatory  of  Music  (James  D.  Vaughn) ....  Lawreneeburg,  Tenn. 

Lyradion  Mfg.  Co Mishawaka,  Ind. 

Lundskow.  Henry  P Kenosha.  Wis. 

Boyd  M.  Hamp WUmington,  Del. 

Pennsylvania  National  Guard,    2d   Battalion,    112th    Infantry.  ..  .Erie.  Pa. 

Woodman  of  the  World., Omaha.  Nebraska 

Franklyn  J.  Wolff ' Trenton.  N.  J. 

Palmer  School  of  Chiropractic Davenport,  Iowa 

Triple  AlUance  Radio  Station 8ycamore,  Illinois 

Hotel  Jamestown,  Inc Jamestown,  N.  Y. 

James  K.  O'Dea Paterson.  New  Jersey 

Iowa  State  CoUege Ames,   Iowa 

Neutrowound  Radio  Mfg.  Co Homewood,  HI. 

Otto  Baur New  York.   N.  Y. 

John  Wanamaker ........... Philadelphia.  Pa. 

Unity  School  of  Christianity Kansas  City,  Mo. 

L.  Bamberger  and  Co Newark,  N.  J. 

People's  Pulpit  Assn Batavia,  IU. 

State  Marketing  Bureau Jefferson  City.  Mo. 

Owl  Battery  Company New  Orleans.  La. 

Main  Auto  Supply  Co Fort  Wayne.  Ind. 

Pennsylvania  State  CoUege 8tate  CoUege,  Pa. 

Donaldson  Radio  Co Okmulgee,  Okla. 

Doolittle  Radio  Corp New  Haven,  Conn. 

North  Dakota  Agricultural  CoUege Agricultural  CoUege,  N.  D. 

Superior  Radio  &  Telephone  Equipment  Co Columbus  Ohio 

H.  L.  Turner Buffalo.  N.  Y. 

The  Municipality  of  Atlantic  City Atlantic  City.  N.  J. 

Wilson  Printing  &  Radio  Co Harrisburg,  Pa. 

Horace  A.  Beale,  Jr Parkersburg,  Pa. 

E.  B.  Gisb AmariUo.  Texas 

Moore  Radio  News  Btation  (Edmund  B.  Moore) Springfield.  Vt. 

Electrical  Equipment  Co Miami,  Fla. 

Scranton  Times Scranton,   Pa. 

Calvary  Baptist  Church New  York,  N.  Y. 

Calumet  Rainbo  Broadcasting  Co Chicago   IU. 

The  Radio  Club  (Inc.) LaPorte.  Ind. 

Lombard   CoUege Galesburg.    HI. 

St.  Louis  Radio  Service  Co St.  Louis,  Mo. 

Antioch  CoUege YeUow  Springs.  Ohio 

Avenue  Radio  8hop  (Horace  D.  Good) Reading.  Pa. 

Flaxon's  Garage Gloucester  City.  N.  J. 

Immanuel  Lutheran  Church Valparaiso.  Ind. 

Radio  Corp.  of  America Washington,  D.  C. 

Reo  Motor  Car  Co Lansing,  Mich. 

Washington  Radio  Hospital  Fund Washington,  D.  C. 

Rosedale  Hospital,  Inc Minneapolis,  Minn. 

Doron  Bros Hamilton.  Ohio 

Union  College Schenectady,  N.  Y. 

University  of  Illinois TJrbana.  IU. 

A.  H.  Grebe  &  Co.  .Inc.  .Motor  Yacht  "MU-1" New  York.  N.Y. 

Experimenter  Publishing  Co New  York.  N.  Y. 

Radiotel  Mfg.  Co. .  Inc Bay  Shore.  New  York 

Tarrytown  Radio  Res.  Labs Tarrytown.  N.  Y. 

United  States  Playing  Card  Co Cincinnati.  Ohio 

Grove  City  CoUege Grove  City,  Pa. 

AUentown  Call  Publishing  Co - AUentown,  Pa. 

Seventh  Day  Adventist  Church New  York,  N.  Y. 


219 
216 
226 
20S 
246 
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222 
220 
20S 
231 
360 
509 
229 
352 
281 
254 
268 
306 
286 
322 
207 
207 
234 
224 
219 
233 
270 
256 
229 
303 
517 
405 
455 
278 
240 
261 
340 
28S 
254 
214 
231 
286 
216 
210 
275 
417 
250 
286 
283 
231 
278 
278 
303 
344 
258 
422 
288 
261 
440 
273 
212 
286 
447 
280 
261 
250 
256 
384 
503 
341 
321 
284 
258 
255 
271 
230 
254 
248 
268 
526 
260 
280 
274 
392 
280 
369 
225 
360 
242 
S26 
240 
484 
205 
27S 
203 
270 
217 
233 
509 
278 
405 
275 
440 
270 
227 
283 
360 
268 
283 
286 
205 
300 
216 
270 
234 
275 
283 
280 
260 
447 
224 
244 
263 
242 
238 
268 
278 
468 
286 
256 
252 
360 
270 
273 
236 
258 
21« 
273 
325 
258 
229 
263 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


60 


Langmuir  Finally  Gets  Patent 

( Continued  from  page  65) 

and  the  merit  of  the  invention  was  even- 
tually sustained  by  the  Patent  Office, 
after  an  attack  for  which  there  are  few 
precedents  in  vigor  or  in  skill.  There- 
upon the  contest  became  one  to  deter- 
mine whether  Dr.  Langmuir  or  the  later 
applicant  was  the  first  inventor,  and 
more  testimony  had  to  be  taken  by  both 
parties  to  establish  their  dates  of  inven- 
tion. The  Examiner  of  Interferences 
adjudged  Dr.  Langmuir  the  first  inven- 
tor. On  appeal  to  the  Examiners-in- 
Chief  the  decision  was  again  in  favor  of 
Dr.  Langmuir.  On  further  appeal,  the 
Assistant  Commissioner  held  in  favor  of 
the  later  applicant.  But  on  still  further 
appeal  to  the  Court  of  Appeals  of  the 
District  of  Columbia,  the  Assistant 
Commissioner  was  reversed  and  the 
Court,  agreeing  with  the  Examiner  of 
Interferences  and  the  Examiners-in- 
Chief,  found  that  Dr.  Langmuir  was  the 
prior  inventor.  The  appeals,  though 
diligently  prosecuted,  were  not  termin- 
ated until  June  of  the  present  year. 

Dr.  Langmuir  is  a  world  known  scien- 
tist and  inventor.  Among  a  large  num- 
ber of  other  scientific  and  practical  in- 
ventions made  and  patented  by  him, 
the  best  known  is  probably  the  Type  C, 
or  gas-filled  Mazda. 

The  application  of  Dr.  Langmuir's 
vacuum  tube  invention  to  X-ray  tubes 
was  the  invention  of  Dr.  William  D. 
Coolidge,  another  world  known  scientist- 


inventor  working  in  the  research  labora- 
tory of  the  General  Electric  Company 
at  Schenectady.  The  Coolidge  X-ray 
tube,  embodying  the  inventions  of  Dr. 
Langmuir  and  Dr.  Coolidge,  is  now  in 
operation  in  all  hospitals  and  X-ray 
laboratories. 


A  Universal  Socket  with 
Isolantite  Insulation 

Granted  that  there  is  nothing  novel 
in  the  universal  socket  idea,  since  many 
sockets  of  this  type  have  now  appeared 
on  the  market  to  take  care  of  the  new 
X  type  tubes  as  well  as  the  old  standard 
UV  and  C  types,  the  fact  remains 
that  the  Pacent  Universal  Socket  has 
several  features  which  stamp  it  as  de- 
cidedly different. 

The  Pacent  Universal  Socket  is  entirely 
made  of  isolantite — the  super-insulating 
material — with  the  exception  of  its  metal 
parts.  Therefore,  the  capacity  effect 
between  plate  and  grid  is  practically 
negligible,  which  is  a  distinct  advantage 
in  many  of  the  highly  critical  circuits  now 
in  use.  The  contact  members  are  of  the 
one-piece  phosphor-bronze  type,  with 
Pacent  self-cleaning,  side-wiping  contact 
for  each  tube  prong.  Connections  can  be 
made  by  means  of  the  slotted  hexagon 
nut  binding  posts,  or  by  soldering  to  the 
soldering  lugs.  The  Pacent  Universal 
Socket  is  supplied  in  the  popular  mount- 
ing type  and  also  for  mounting  on  sub- 
panels. 


OTje^atflc  Cop 
yfthejiir  r 

Add  a  Ferbend  Wave  Trap 
to  your  Radio  Set  and  "Police" 
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original   and    only  successful 
WAVE  TRAP.    Now  in  its 
fourth  year.  Sent  postpaid  up- 
on receipt  of  $8.50  or  C.  O.  D. 
plus  postage.    Send  for  Free 
Booklet. 
Ferbend  Electric  Co. 
431 W.  Superior  St.,  Chicago 
Seethe  new  Ferhend"  B" 
Eliminator  announcement 
on  page  58 

FERBEHP 


U.  S.  Post  Office, 
Billings,  Mont. 

"Ferbend  Electric  Co. 
Gentlemen: 

With  my  Fada  Neu- 
trodyne  and  Ferbend 
Wave  Trap  I  received 
the  address  of  Prea. 
Coolidge  fromWOAW 
Omaha,  on  a  special 
wave  length.  Many 
fan.3  tried  to  get  it  but 
failed.  Also  the  base- 
ball World  Series  from 
WOAW  and  KM  A, 
Shetland  'ah,  Iowa. 
Had  W  E  A  F,  New 
York,  loud  enough  to 

street.     Will   put   my 
Set  and  Wave  Trap  up 
against  any  in  the  city 
regardless  of  price. 
(Signed) 

J.  A.  Thompson, 
Sapt.  of  Mails."    w 

vSsSfSsSsk 


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When  you  install  Barrett  &.Paden  condensers  in  any  set  you  immediately  increase 

its  capabilities  many  fold.  These  condensers  bring  in  stations  which,  because  of 

the  characteristics  of  your  other  condensers,  could  not  be  found.    Separating 

stations  which  are  closely  upon  one  another  is  easy  and  positive 

because  of  the  wider  range  of  minute  capacity  variations  which  this 

and  only  this  condenser  has. 

TheBarrett  &.  Paden  Condenser  works  like  a  mechanic's  micrometer.  Just  as  this 
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ute distances,  so  the  Barrett  &_  Paden  Micrometer  Condenser  makes  it  possible  to 
obtain  the  minute  capacity  variations  so  necessary  for  precision  tuning. 

Build  your  next  set  with  Barrett  6k.  Paden  Micrometer  Type 
Condensers.  The  tremendous  difference  in  performance  will 
amaze  you.  You  will  have  a  set  which  will  do  things  almost 
beyond  the  belief  of  anyone  who  has  not  seen  the  set  in  ac- 
tual operation.  At  your  dealers 
or  direct. 

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BBBBETTJ,  PBDEN 

1314  Sedgwick  St.,   Chicago,  111. 

Prepared  by  Kirtland-Engel  Adv.  Co.,  Chicago 


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.0005 
Straight  Line  Capacity 


*    Tested  and  Approved  by  RADIO  AGE    * 


70 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


WSAR  Iff  Uaughty  St  Welch  Electrical  Co Fall  River,  Mass.  2S4 

WSA2       Clias.  Electric  Shop Pomeroy,  Ohio  258 

WSB  Atlanta     Journal Atlanta.     Ga.  428 

WSBC        World  Battery  Co 1219  S.  Wabash  Ave.,  Chicago.   III.  210 

WSBF       Stis-Baer-Fuller  D.  G.  Co St.  Louis,  Mo.  275 

WSKC       World's  Star  KuittinE  Co Bay  City,  Mich.  261 

WSM  Nashville  Life  and  Accident  Ins.  Co Nashville.  Tenn.  283 

WSMB      Saeneer  Amusement  Co..  and  Maison  Blanche  Co New  Orleans.  La.  319 

WSMH     Shattuck    Music  House Owosso,  Mich.  240 

WSMK     S.  M.-K.  Radio  Corp Dayton.  Ohio  275 

WSOE       School  of  Engineering Milwaukee,   Wis.  248 

WSTA       Camp  Maiienield Cheshom.  N.  H.  229 

WSUI        State  University  of  Iowa Iowa  City.  Iowa  498 

WTAB       Fall  River  Daily  Herald  Publishing  Co '. Fall  River,  Mass.  248 

WTAC       Penn    Traffic    Co Johnstown,    Pa.  360 

WTAD      Robt.  E.  Compton Carthage.  111.  238 

WTAG       Telegram  Pub  .Co Worcester,  Mass.  268 


WTAL  Toledo  Radio  4  Electric  Co Toledo.  Ohio  252 

WTAM  Williard  Storage  Battery  Co Cleveland,  Ohio  390 

WTAP  Cambridge  Radio  &  Electric  Co Cambridge,  III.  242 

WTAQ  S.  H.  Van  Gordon  &  Son Osseo,  Wis.  220 

WTAR  Reliance    Electric    Co Norfolk,    Va.  283 

WTAT  Edison  Electric  Illuminating  Co  (portable) .  .Boston.  MasB.  240 

WTAW  Agricultural    &    Mechanical    College    of    Texas College    Btation.    Texas  280 

WTAX  Williams    Hardwaro   Co Streator.  111.  231 

WTAZ  Thomas  J.  McGuire Lambertville,  N.J.  283 

WTG  Kansas  State  Agricultral  College Manhattan,  Kans.  273 

WTIC  Travelers  Insurance  Co Hartford.  Conn.  323 

WTX  H.    G.   Saal  Co Chicago.  111.  268 

WWAD  Wright  4  Wright  (Inc.) Philadelphia.  Pa.  360 

WWAE  The   Alamo   Ball   Room Joliet.  111.  242 

WWI  Ford  Motor  Co Dearborn,  Mich.  273 

WWJ  Detroit  News  (Evening  NewB  Assn.) Detroit.  Mich.  352 

WWL  Loyola  University New  Orleans.  La.  2(0 


FOREIGN  BROADCASTING  STATIONS 


CFAC 

CFCA 

CFCF 

CFCH 

CFCK 

CFCN 

CFCR 

CFCT 

CFCU 

CFHC 

CFKC 

CFQC 

CFRC 

CFXC 

CFYC 

CHBC 

CHCM 

CHCS 

CHIC 

CHNC 

CHUC 

CHXC 

CHYC 


PWX 

2BY 

2CX 

2DW 

2EV 

2HC 

2HS 

2JD 

2K 

2KD 

2LC 

2MG 

2MN 

2QL 


2LO 
SIT 
SWA 
6BM 
2ZY 


Canadian 


Calgary    Herald Calgary, 

Toronto  Star  Pub.  &  Prtg.  Co Toronto 

Marconi  Wireless  Telee.  Co..  (Ltd.)  Canada Montreal 

Abitibi  Power  &  Paper  Co.,  (Ltd.) Iroquois  Falls 

Radio  Supply  Co Edmonton , 

W.   W.   Grant   (Ltd.) Calgary, 

Laurentide  Air   Service Sudbury 

Victoria  City  Temple Victoria, 

The  Jack  Elliott  (Ltd.) Hamilton 

Henry   Birks   &   Sons Calgary, 

Thorold    Radio    Supply Thorold. 

The  Electric  Shop   (Ltd.) Saskatoon. 

Queens    University Kingston . 

"Westminster    Trust    Co Westminster, 

Commercial    Radio    (Ltd.) Vancouver, 

The  Galcary  Albertan Calgary, 

Riley  &   McCormack   (Ltd.) Calgary, 

The  Hamilton  Spectator Hamilton 

Northern    Electric    Co Toronto, 

Toronto  Radio  Research  Society Toronto 

International  Bible  Aas'n Saskatoon. 

R.    Booth,   Jr Ottawa 

Northern    Electric    Co Montreal. 


434  CJCA  Edmonton  Journal Edmonton,   Alta. 

357  CJCL  A.   Couture - Montreal,  Qu«. 

411  CJGC  London   Free   Press .- London,   Ont. 

500  CKAC  La     Presse Montreal,    Que. 

Alta.     517  CKCD  Vancouver  Daily  Province Vancouver,  B.  C. 

Alta.     434  CK.CK  Leader    Pub.    Co Regina.   Sask. 

,  Ont.     410  CKCO  Ottawa    Radio    Association Ottawa,    Ont. 

B.  C.     329  CKCX  P.  Burns  &   Co..   (Ltd.) Calgary,  Alta. 

341  CKFC  First  Congregational  Church Vancouver,  B-  C. 

434  CKLC  Wilkinson   Electric   Co.,    (Ltd.) Calgary,  Alta. 

,    Ont.     248  CKNC  Canadian    National  Carbon   Co Toronto,  Ont. 

Sask.     329  CKOC  Wentworth  Radio  Supply  Co Hamilton,  Ont. 

Ont.     450  CKY  Manitoba  Tel.  System Winnipeg.  Man. 

B.    C.     291  CNRA  Canadian  National  Railways Moncton.  N.  B. 

B.   C.     411  CNRC  Canadian  National  Railways Calgary ,  Canada 

Alta.     434  CNRE  Canadian  National  Railways Edmonton,  Alta. 

Alta.     434  CNRM  Canadian  National  Railways Montreal,  P.  Q. 

Ont.     341  CNRO  Canadian    National   Railways Ottawa,   Ont. 

Ont.     357  CNRR  Canadian    National   Railways Regina,  Sask. 

Ont.     357  CNRS  Canadian  National  Railways Saskatoon,  Sask. 

Sask.     329  CNRT  Canadian   National   Railways Toronto,  Ont. 

Ont.     434  CNRV  Canadian  National  Railways Vancouver,  B.  C. 

Que.     411  CNRW  Canadian  National  Railways Winnipeg,  Man. 


Cuban 


Cuban  Telephone  Co Habana  400  2TW 

Frederick  W.  Borton Habana  260  2WW 

Frederick  W.  Borton Habana  320  5EV 

Pedro  Zayas Habana  300  6BY 

Westinghouse  Elec.  Co Habana  220  6CX 

Heraldo  de  Cuba Habana  275  6DW 

Julio  Power Habana  180  6KJ 

Raul  Parez  Falcon Habana  105  6KW 

Alvara  Daza Habana  200  8BY 

E.  Sanchez  de  Fuentes Habana  350  8DW 

Luis  Casas Habana  250  8FU 

Manuel  G.  Salas Habana  280  12AB 

Fausto  Simon ~ Habana  270  16AZ 

Oscar  Collado Habana  290  20K 


Roberto  E.  Rami  res Habana 

Amadeo  Saenz Habana 

Leopoldo  E.  Figueroa. Colon 

Jose  Ganduxe Cienfiegos 

Antonio  T.  Figueroa Cienfiegos 

Eduardo  Terry Cienfiegos 

Frank  H.  Jones Tuinucu 

Frank  H.  Jones Tuinucu 

Alberto  Ravelo Stgo.  de  Cuba 

Pedro  C.  Anduz Stgo.  de  Cuba 

Andres  Vinnet , Stgo.  de  Cuba 

Alberto  S.  de  Bustamante Habana 

Valentin  Ullivarri Cienfiegos 

Mario  Garcia  Velez Habana 


British 


511 
279 
321 
411 
397 
478 
434 
434 
411 
434 
357 
341 
384 
312 
434 
517 
411 
434 
478 
329 
357 
411 
384 


230 
210 
360 
300 
170 
225 
275 
340 
250 
275 
225 
240 
200 
360 


London 365  5NO 

Birmingham 475  5SC 

Cardiff 350  2BD 

Bournemouth 385  6SL 

Manchester 375 


Newcastle 400 

Glasgow 420 

Aberdeen 492 

Sheffield  (relay  station) ". 303 


French 


Lyons 740 

Paris  (EifTle  Tower) 2,600 


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powerful  by  replacing  your  T.  R.  F. transformers  with 
Aero  Coils.  Get  Aero  Coils  now  —  and  tune  through 
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Amateur    Radio    Gets 
Recognition 

Amateur  radio  has  received  definite 
recognition  as  an  international  under- 
taking of  value  to  the  entire  world,  with 
the  official  acceptance  of  the  Inter- 
national Amateur  Radio  Union  by  the 
League  of  Nations  headquarters  in 
Geneva.  This  organized  group  of  ama- 
teur radio  telegraphers  has  branches  in 
most  of  the  civilized  countries  of  the 
globe  and  sections  are  in  process  of  form- 
ing in  those  countries  not  yet  represented. 

In  the  United  States  and  Canada,  the 
Union  has  thriving  sections,  with  the 
20,000  members  of  the  American  Radio 
Relay  League  as  a  nucleus. 

Officers  of  the  Union  are  International 
President  Hiram  Percy  Maxim  of  Hart- 
ford, Conn.;  International  Vice  Presi- 
dent, Gerald  Marcuse  of  Caterham, 
Surrey,  England;  International  Secre- 
tary-Treasurer, K.  B.  Warner  of  Hart- 
ford, Conn.;  International  Counsellors- 
at-large,  Jean  G.  Mezger,  Nueilly-sur- 
Seine,  France,  and  Frank  D.  Bell, 
Palmerston,    South,    New    Zealand. 

The  organization  aims  to  promote 
cooperative  regulation  for  international 
amateur  radio  communication,  to  pro- 
vide international  amateur  tests  and  to 
develop  a  system  of  handling  interna- 
tional private  messages  based  upon  the 
message  plan  now  in  use  with  the  Ameri- 
can Radio  Relay  League. 
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451ltomasmodava,,DepL2iz  Chfem.UL 


RADIO  AGE  for  December,  1925 


A  Guide  to  Readers  who 
Want  Radio  Books 

IN  THE  belief  that  our  readers  will  be 
interested  in  knowing  where  to 
obtain  booklets  on  various  radio 
subjects,  from  manufacturers,  engineers, 
and  other  sources,  RADIO  AGE  is 
continuing  the  publication  of  its  directory 
for  such  literature. 

The  title  of  the  booklet,  the  person  or 
company  from  whom  it  can  be  obtained 
and  the  latter's  address,  are  given  for 
your  convenience.  This  service  will  be 
continued  from  month  to  month  in 
RADIO  AGE,  and  readers  desiring  to 
know  where  to  get  literature  not  listed 
herewith  may  obtain  this  information  by 
addressing  our  Technical  Department. 

The  directory  for  this  month  follows: 

Free  mailing  lists  of  prospective  cus- 
tomers. Ross  Gould  Co.,  589  North  10th 
St.,  St.  Louis,  Mo. 

Circular  covering  cabinets  and  con- 
soles. Raulf  Radio  Console  Mfg.  Co., 
562  Vedder  St.,  Chicago,  111. 

Sales  proposition  and  discount  terms, 
also  booklet  R-A.  Diana  Radio  Co., 
1429  South  Michigan  Ave.,  Chicago,  111. 

Reference  book  for  direct  mail  ad- 
vertisers. R.  L.  Polk  &  Co.,  599  Polk 
Director  Bldg.,  Detroit,  Mich. 

Catalog  L1003  for  radio  parts  with 
list  of  discounts.  Wakem  &  McLaughlin, 
225  East  Illinois  St.,  Chicago,  111. 

Booklet  31,  covering  use  of  bakelite  in 
radio.  Bakelite  Corporation,  247  Park 
Ave.,  New  York,  N.  Y. 

Tube  characteristics.  Cleartron  Tube 
Co.,  28  West  44th  St.,  New  York,  N.  Y. 

Radio  products.  Acorn  Radio  Products 
Co.,  712  West  Madison  St.,  Chicago,  111. 

Seven  hook-ups  in  blueprint  form.  A 
F.  Henninger  Corp.,  4507  Ravenswood 
Ave.,  Chicago,  111. 

Illustrated  folder  of  sets  made  by 
W-K  Electric  Co.,  Kenosha,  Wis. 

Pamphlet  15-B  descriptive  of  electrical 
instruments  for  radio  purposes,  Jewell 
Electrical  Instrument  Co.,  1650  Walnut 
St.,  Chicago,  111. 

General  catalog  including  radio  hook- 
ups, Barawik  Co.,  104-126  South  Canal 
St.,  Chicago,  111. 

General  catalog  of  radio  parts  and  kits, 
W.  C.  Braun  Co.,  36-50  South  Clinton 
St.,  Chicago,  111. 

Illustrated  1926  radio  catalog,  and 
free  log  Economy  Radio  Sales  Co.,  288 
6th  Ave.,  Dept.  C,  New  York  City,  N.  Y. 

Literature  on  tandem  condensers, 
Duplex  Condenser  and  Radio  Corp.,  42 
Flatbush  Ave.,  Extension,  Brooklyn,  N.Y 

Descriptive  folder  covering  radio 
parts,  Telephone  Maintenance  Co.,  Dept. 
C,  South  Wells  St.,  Chicago,  111. 

Complete  catalog  of  parts,  (also 
Resistance  Coupled  Manual  30  cents) 
Daven  Radio  Corporation,  158-160  Sum- 
mit Ave.,  Newark,  N.  J. 

Data  on  resistance  coupled  amplifiers, 
Allen-Bradley  Co.,  289  Greenfield  Ave., 
Milwaukee,  Wis. 

Fifty-two  page  catalog  covering  all 
typesof  radio  sets  and  parts.  Montgomery- 
Ward  and  Co.,  Dept.  18-R,  Chicago,  111. 

Latest  data  on  audio  frequency  am- 
plification.   Electrical    Research    Labora- 


tories, 2500  Cottage  Grove  Ave.,  Dept 
6-C,  Chicago,  111. 

Literature  on  radio  parts,  Steinite 
Laboratories,  302  Radio  Bldg.,  Atchison, 
Kansas. 

Literature  on  1  to  5  tube  sets,  Midwest 
Radio  Corp.,  523  B  East  8th  St.,  Cin- 
cinnati, Ohio. 

Literature  on  inductances  and  allied 
products,  Aero  Products,  Inc.,  217  North 
Desplaines  St.,  Chicago,  111. 

Literature  on  Lavite  resistances,  Cres- 
cent Radio  Supply  Co.,  Liberty  St., 
Jamica,  N.  Y. 

Literature  on  Ozarka  instruments  No. 
200,  Ozarka  Inc.,  122  Austin  Ave.,  A, 
Chicago,  111. 

General  catalog  including  list  of 
stations  and  general  radio  information, 
Randolph  Radio  Corp.,  159  North  Union 
Ave.,  Dept.  185,  Chicago.  111. 


The  Magazine  of  the  Hour  71 

Perfect  Alignment  in 
Perryman  Tube 

Making  somewhat  of  a  departure  in 
tube  construction  the  Perryman  Electric 
Co.,  have  placed  on  the  market  the 
Perryman  tube  in  which  the  plate,  grid 
and  filament  elements  are  held  in  perfect 
alignment  by  a  non-conducting  bridge 
located  at  the  top  and  bottom  of  the  tube, 
thus  insuring  rigid  tension  on  all  the 
elements. 

A  set  of  these  tubes  used  in  Radio  Age's 
laboratory  operated  with  uniform  good 
results  in  a  three  tube  set,  a  five  tube 
tuned  r.f.  and  an  8  tube  super-het.  The 
grid  to  filament  capacity  seems  to  be  less 
in  this  type  of  tubes  and  they  served  as 
excellent  r.f.  amplifiers.  The  filament 
current  is  the  conventional  quarter  of  an 
ampere,  operated  off  a  six  volt  battery. 
The  Perryman  Electric  Co.,  also  makes 
199  type  with  the  same  bridge  suspension. 


uKsomm 


* 


LOUD  SPEAKER 


*    Tested  and  Approved  by  RADIO  AGE    * 


72 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


Radio  Parts  FREE! 

If  your  friends  are  not  receiving  RADIO  AGE  each  month,  ask  them  to  subscribe  through 
you,  then  pick  out  your  prize  from  the  list  of  guaranteed  radio  parts  given  below.  Each  part 
has  been  tested  and  approved  by  the  RADIO  AGE  INSTITUTE,  which  assures  you  of  the  best 
parts  made.     More  complete  description  will  be  sent  upon  request. 

The  subscription  price  is  $2.50  a  year.  Send  in  your  new  subscriptions  with  the  checks 
or  money  orders  and  the  premium  you  want  will  be  sent  immediately. 

Get  in  on  this  now! 


For  ONE  new  subscription    the   following  parts   are 
offered  as  your  premiums: 

1.  AMSCO  Bakelite  Dials,  100  graduations,  2,3  or  4 
inches. 

2.  AMSCO  Tube  Sockets,  panel  or  table  mounting. 

3.  EVER  READY  C  Battery. 

4.  BURGESS  C  Battery. 

5.  RED  SEAL  Dry  Cell  Battery. 

6.  BREMER  TULLY  type  U  L  Socket.  Eliminates 
use  of  adapters. 

7.  RADIALL  "AMPERITE,"  a  "self  adjusting" 
rheostat.  Does  away  with  hand  rheostats  and 
filament  meters. 

For  TWO  new  subscriptions  the  following  parts  are 
offered  as  your  premiums: 

1.  AMSCO  Rheostats,  Arrow  Knob  or  Bakelite  Dial. 
2,  6,  8,  10,  12,  15,  20,  30,  or  50  Ohm. 

2.  AMSCO  Potentiometers,  Arrow  Knob  or  Bakelite 
Dial.  250  or  400  Ohm. 

3.  AMSCO  Grid-Leak  and  Condenser.  Fixed  con- 
denser, .00025  mfd.  capacity  and  Grid-Leak,  2 
Megohms. 

4.  Genuine  non-inductive  CRESCENT  LAVITE 
Resistances.  12,000,  48,000,  50,000,  or  100,000 
ohms. 

5.  DAVEN  LEAKANDENSER.  Combination  grid 
leak  and  grid  condenser.   2,  3,  4,  5,  or  7  megohms. 

6.  DAVEN  RESISTO  Couplers.  Two  pair  of  clips, 
one  for  holding  the  plate  resistor  and  one  for 
holding  the  grid  leak. 

7.  STEINITE  Interference  Eliminator.   Enables  you 
to  tune  out  locals  and  get  distant  stations. 
Small  BURGESS  "B"  Battery. 
Small  EVER  READY  "B"  Battery. 


9. 
Foi 


THREE  new  subscriptions    the  following  parts 
to  choose  from: 
CRESCENT    Bakelite    Panels.      %°    thick.      Size 
7"xl0"  or  7"xl2". 

BREMER-TULLY  Variable  High  Resistances. 
Maximum  resistances  of  2,000,  50,000,  100,000  or 
200,000  ohms. 

BREMER-TULLY  Volume  Control  or  Modulator. 
Used  in  audio  circuits  for  noiseless  adjustment  of 
volume  and  improvement  of  tone  qualities. 
BREMER-TULLY  Non-inductive  Potentiometer. 
A  variable  high  resistance  with  three  terminals. 
Slider  connects  to  center  terminal  and  varies  at 
either  outer  terminal  to  maximum  resistance. 
400  or  2,000  Ohm  maximum  resistance. 


Fo 


FOUR    new    subscriptions    the    following    pre- 
miums  to  choose  from: 
KLADAG    EUPHONE,    Bakelite    base,     no    tip, 
thoriated  filament  tube.    201A  or  199  type. 
CRESCENT  Bakelite  Panels.     %°  thick.     7"xl4" 
or  7"xl6"  or  7"xl8". 

VAN  HORNE  3VA  "Double  Service"  or  Com- 
promise Tube.  Operates  at  3  volts  from  either 
dry  cells  or  batteries. 

BREMER-TULLY  Tuning  Control.    12  to  1  ratio. 
Provides   positive    control    with    a   smooth    easy 
action.   With  disc  for  marking  station  call  letters. 
For  FIVE  new  subscriptions  you  can  pick  your  pre- 
miums from    the  following: 

1.  ENSIGN  Variable   Condenser.     Either   .00025   or 
.0005  capacity. 

2.  MUSSELMAN  Selective  Antenna.    75  foot  length 
coil. 
Model  5VA,  3VA  or  3VB  MUSSELMAN  Certified 


1. 


4. 


3. 


5. 


Electron  Tubes.    5VA  and  3VA  fit  201-A  sockets 

3VB  fits  199  sockets. 

AMSCO   Allocating   Condenser.      Straight   Line 

Frequency.    13  plates  or  17  plates,  .0003  or  .00035 

mfd.  Single  unit. 

CRESCENT  Bakelite  Panel.    %"  thick.  7"x21". 


For  SIX  new  subscriptions  you  have  the  following 
to  choose  from: 

1.  The  AERO  COIL  Wave  Trap  Unit.  Makes  a  very 
efficient  wave   trap  or  crystal  set. 

2.  CRESCENT  Bakelite  Panels.  %"  thick.  7"x24"  or 
7"x26". 

3.  SILVER-MARSHALL  S.L.W.  type,  .00025,  11 
plate,  or  .00035,  17  plate,  condensers.  Silver 
plated.    Three  inches  square. 

4.  BREMER-TULLY  Three  Circuit  Tuner.  A  tuner 
of  unquestioned  merit  for  use  in  one  to  four  tube 
sets.  Two  types,  for  200  to  566  meters  reception 
and  for  50  to  150  meters  reception. 

5.  BREMER-TULLY  "Torostyle"  Transformers. 
Three  types:  Antenna  Coupler,  for  Intermediate 
R.  F.  Stages,  and  for  four  tube  sets. 

6.  WERNER  Radio  Frequency  Transformer,  Type 
W-l,  W-2,  or  W-3 

For  EIGHT  new  subscriptions  we  offer  the  following 
premiums: 

1.  AERO  COIL  Oscillator  for  Super  Heterodynes,  as 
advertised  in  RADIO  AGE. 

2.  CREST  Convertible  Condenser.  23  plate.  Con- 
vertible to  all  capacities.    S.L.F. 

3.  Model  5VC  MUSSELMAN  Certified  Electron 
Tube.  Fits  201-A  sockets. 

4.  SILVER-MARSHALL  type  105  Low  Loss  Coupler. 
For  three  circuit,  tuned  R.F.,  or  other  circuits 
requiring  a  highly  efficient  inductance  unit. 
Wave  length  range,  with  stator  shunted  by  .0005 
mfd.  condenser,  200  to  550  meters. 

5.  SILVER-MARSHALL  S.L.F.  type,  .0005  mfd.,  35 
plate,  or  .00035,  25  plate,  or  .00025,  17  plate 
condensers.    Silver  plated.    Three  inches  square. 

6.  Seven  by  eighteen  inch  cabinet  with  hinged 
cover.    (SILVER-MARSHALL). 

7.  BREMER-TULLY  "Euphonic"  Audio  Trans- 
formers. Type  210,  ratio  2.2  to  1  and  Type  410, 
4.7  to  1. 

8.  BREMER-TULLY  S.L.F.  condensers.  13  or  17 
plate,  .00025  or  .00035  mfd. 

For  TEN  new  subscriptions  you  can  pick  your  prize 
from  this  list: 

1.  The  AERO  COIL  Three  Circuit  Tuner.  Advertised 
in  RADIO  AGE. 

2.  AMSCO  ALLOCATING  Condensers.  S.L.F.  17  or 
23  plates,  .00035  or  .0005  mfd.    Double  Unit. 

3.  KLADAG  Knock  Down,  Mahogany  Loop  An- 
tenna.   Bank  Wound,  Centre  Tapped. 

4.  STEINITE  long  distance  crystal  set.  In  beautiful 
hand-rubbed,  walnut  finish  case. 

5.  STEINITE  one  tube  regenerative  set.  1500  mile 
range.    Mahogany  cabinet. 

6.  SILVER-MARSHALL  "Two  Ten"  Transformer. 
A  long  wave  inter-stage  transformer,  peaking  at 
60  kilocycles.  Combination  iron  core  type  and 
air  core  type.     Turn  ratio,  1  to  2.3. 

7.  SILVER-MARSHALL  "Two  Eleven"  Transformer. 
Peaks  at  60  kilocycles  in  conjunction  with  the 
tuning  condenser  supplied.  Air  core  type.  May 
be  used  at  input  or  output  end  of  the  amplifier, 
turn  ratio  1  to  10.  Complete  with  60RC  tuning 
condenser. 


RADIO    AGE,    Inc.,    500  N.  Dearborn  Street,  Chicago 


*    Tested  and  Approved   by  RADIO   AGE    * 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


73 


CROSLEY  Radios    with 

these  New  Prices  should 

be  Radio's  best  values! 

Crosley  2-Tube  51  Regular 


This  efficient  little  set  uses  any  make  of 
tubes.  Nearby  stations  on  loud  speaker, 
long  range  on  headphones. 

NOW  $14.75  &Aio 

Crosley  3-Tube  52  Regular 


For  a  less  expensive  3-tube  set  the 
Crosley  52  Regular  cannot  be  surpassed 
at  the  new  low  price. 

NOW  $25.00  ££. 

Crosley  Super-Trirdyn  Regular 


In  the  Super-Trirdyn,  3  tubes  do  the 
work  of  5.  Matchless  performance. 
Beautifully  finished  solid  mahogany 
cabinet. 


NOW  $45.00  £oA 


WAS 

00 


The  Famous  Musicone 

This  marvelous  loud  speaker 
-well  on  its  way  to  RE- 
PLACE HALF  A  MILLION 
HORNTYPE  SPEAKERS  by 
January  1st — is  substantially 
reduced  because  of  assembly 
improvements  developed  by  Crosley 
engineers.  Reproduces  all  tones — without 
distortion.  Crosley  patented  unit,  not 
cone,  secret  of  its  amazing  perfection. 

NOW  $14.75  S 

These  prices  do  not  include  accessories.     Add 
ten  per  cent  to  all  prices  West  of  the  Rockies. 

BETTER  COSTS        LESS 

THE  CROSLEY  RADIO  CORPORATION 

Dept.  63  Cincinnati,  Ohio 


DON'T    WAIT!     PEP    UP    THAT    SET    NOW    WITH 

X-L  VARIO  DENSERS 

ENDORSED    BY    ALL    LEADING    RADIO    AUTHORI- 
TIES   FOR   USE   IN    THE    LATEST   AND 
BEST    CIRCUITS. 

MODEL  N — Capacity  range  1.8  to  20  micro- micro- 
farads, for  balance)  in  Roberts  two  tube,  Browning- 
Drake,  McMurdo  Silver's  Knockout,  Neutrodyne  and 
tuned  radio  frequency  circuits.  Price,   $1.00 

MODEL  Q — Two  capacity  ranges,  ,00016  to  .00055  ana 
.0003  to  .001  Microfarads,  for  the  Cockaday  circuit, 
filter  and  intermediate  frequency  tuning  in  superhetero- 
dyne and  positive  grid  bias  in  all  sets.  Price  $1.50 

X-L    RADIO    LABORATORIES, 
2424    Lincoln    Ave.    N,  CHICAGO 


Fourth  Chicago  Radio  Show 
Nov.  17-22 

THE  doors  of  the  Coliseum  will  open 
on  the  greatest  radio  exposition  in 
the  history  of  the  industry,  when 
the  fourth  annual  Chicago  Radio  Show 
begins  Tuesday,  November  17  and  con- 
tinues until  the  22nd. 

The  number  of  exhibitors  and  the 
variety  of  features  will  eclipse  all  other 
shows,  and  it  is  expected  the  attendance 
will  be  greater  than  any  other  radio 
show  this  year,  or  in  past  years.  Over  a 
quarter  of  a  million  dollars  has  been  spent 
by  the  management  of  the  show  and  the 
exhibitors,  in  preparing  this  enormous 
spectacle  for  displaying  the  latest  in 
radio  to  the  public 

New  Equipment 

Entire  new  equipment  and  booth  con- 
struction will  be  used  this  year,  it  will 
be  decorated  differently  from  last  year, 
and  will  be  much  more  attractive  gener- 
ally. Manufacturers  have  also  learned 
the  necessity  of  putting  in  real  exhibits 
and  showing  something  distinctive,  in 
order  that  they  may  attract  the  public, 
and  the  displays  will  reflect  this  during 
the  week. 

A  number  of  features,  including  a 
monster  set  building  contest,  in  which 
prizes  amounting  to  $1,000  are  offered 
for  the  best  handiwork  of  radio  fans, 
have  been  planned.  This  contest  is 
divided  into  nine  sections,  with  a  prize 
for  the  best  set  in  each  division.  This 
gives  everyone  a  fair  chance  to  win  one 
of  the  prizes,  and  does  not  place  the 
girls  in  competition  against  the  boys, 
who  are  apt  to  be  more  experienced,  or 
the  boys  against  the  men.  The  sets  are 
to  be  on  exhibition  at  the  show  in  a  spe- 
cial   section    reserved    for    this    purpose. 

Miss  Radio  On  the  Job 

Miss  Radio,  the  girl  radio  fan  from 
Illinois,  Indiana,  or  Wisconsin  with  the 
best  long  distance  reception  record,  will 
be  the  guest  of  the  management  and  will 
be   crowned   as   queen   of   the   show. 

Special  features  of  the  show  will  be 
an  exhibition  of  radio  currents  frying  an 
egg  on  top  of  a  cake  of  ice,  lighting  elec- 
tric light  globes  without  wires,  and  other 
marvelous  tricks  that  seem  beyond 
human  belief.  The  unseen  ether  waves 
will  be  harnessed  to  do  man's  bidding, 
and  perform  a  number  of  unnatural 
stunts. 

A  complete  list  of  foreign  exhibits 
will  be  displayed,  and  it  is  expected 
that  a  good  many  foreign  representatives 
will  be  present  in  person  to  view  the 
latest  in  advancement  of  American 
radio  apparatus. 

Smallest  Radio  Sets^j 

In  another  section  of  the  show  will 
be  an  exhibition  of  the  smallest  radio 
sets  and  parts  in  the  world,  featuring  a 
tiny  loud  speaker  that  just  covers  a 
half-dollar,  complete  receivers  smaller 
than  a  hazelnut,  and  tiny  headphones 
that  would  hardly  be  large  enough  for  a 
small  doll. 

(Continued  on  page  80) 


MbMLowIoss 
INSULATORS 


Storm,  Weather  and  Water  Proof 

pERFECT  your  entire  insulation  by  insulating 
-1-  your  antenna  and  ground  system.  Your  set  is 
not  responsible  for  energy  lost  through  a  poorly  insu- 
lated aerial.  M  &  M  Low  Loss  Lead-in  and  Wall  In- 
sulators will  give  your  net  insulation. 


•X- 


4*  Lead-in  Insulators 50c. 

10*  Lead-in  Insulators 80c. 


20*  Lead-in  Insulators  for  heavy  walls, 
$1.50 

WAXL  INSULATORS 

The  5  in.  "Wall  Insulator  Illustrated 
here  is  made  to  bold  all  sizes  of  wire 
from  4  to  14.  Meets  Underwriters' 
requirements  and  makes  your  antenna 
insulation  perfect. 

Price,  60c. 

Dealers:  If  your  jobber  cannot 
supply  you,  write  us  direct  giving 
your  jobber's  name. 

Send  for  our  catalog 


•  CLEVELAND. OHIO. 


for— 
Real  Enjoyment 


No.  205 


LOUD  SPEAKER 

Assures  utmost  in  volume  and  clarity  of 
tone — reaches  full  range  of  musical  scale,  giv- 
ing a  faithfulness  of  reproduction  that  equals 
hearing  the  original. 

Flare  in  several  handsome  finishes. 

Prices  $22.50  -  $25.00  -  $30.00 

Manufacturers 

irfmmcaa&leclric 

COMPANY 
State  and  64th  Streets 
CHICAGO,  U.  S.  A. 


*     Tested  and  Approved  by  RADIO  AGE    * 


74 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


An     Instru- 
ment    for 
Every  Radio 
Test 

The  Jewell  No.  84 


2-inch  "B"  Battery  Volt- 
meter for  set  owners'  sells 
for  $2.75 :  Our  No.  95  com- 
plete radio  test  set  sells  for 
$75.00.  The  No.  98  double 
reading  voltmeter  (10  and 
50  volts)  shown  opposite  is 
used  by  Dealers  and  Job- 
bers to  check  batteries — 
Price  $12.50. 


Send  for  Jewell  15-B 
Complete  Radio  In- 
strument     Catalog 


Order  from  Dealer 


Jewell  Electric  Instrument  Co. 

1650  Walnut  St.,  -  Chicago 

"26    YEARS   MAKING    GOOD    INSTRUMENTS" 


vClhe  Famous  Truly  Portable 

Telmaco  P-l  Receiver 

Four  Tubes  Do  the  Work  of  Seven 

The  peer  of  portables  in  size,  weight,  ease  of  tuning, 
selectivity,  distance,  volume,  workmanship  and  price. 
Aerial,  loud  speaker  and  batteries  self  contained. 
Complete  with  tubes  and  batteries,  S19R0O 
SHI. 50.  Receiver  only      ....     vl.fcJ»   w 

P-l  Kit  Saves  Yaa  Money! 
Oar  offer  of  the  Telmaco  P-l  Receiver  in  kit  form  has 
met   with  enthusiastic  reception.  This  contains  all 
parts,  as  built  by  us,  including  case,  drilled  and  en- 
graved panel,  and  illustrated  instructions.  £QA  fJQ 

Complete  kit *OU.«"» 

Ask  your  dealer  or  write  us.  Descriptive  folder  free. 
I^adio  'Division: 

Telephone  Maintenance  Co. 

30  So.  Weils  St.    Dept.  C  Chicago,  111. 


Quality  %adio  exclusively    •%>    Established  1918 


NO    MORE    LOOSE    CONNECTIONS 
X-L  PUSH  POSTS 

A  binding  post  that  really  does  excel, 
looka,  action,  service,  and  convenience. 
Push  it  down — insert  wire — cannot  jar 
loose  from  vibration.  No  screwing  or 
danger  of  shearing  off  wires. 
Furnished  attractively  plated  with 
soMtTing  lug  and  necessary  markings. 

Price    Each 15    Cents 

X-L    RADIO    LABORATORIES, 
2424    Lincoln    Avenue    N.  Chicago 


Radio  Plays  Bigger  Part 
in  College  Life 

That  radio  plays  an  important  part 
in  college  and  university  life  is  indicated 
by  the  institutions  which  are  linked 
together  for  the  organ  recitals  presented 
by  the  Skinner  Organ  Company  through 
broadcasting  station  WAHG,  Richmond 
Hill,  N.  Y.,  for  thirty-six  consecutive 
Friday  nights,  which  program  began 
November   6   at   eight   o'clock. 

George  Rogers  Pratt,  Organist  of 
the  University  of  Virginia,  represents 
the  East;  while  Warren  D.  Allen,  organ- 
ist of  the  Leland  Stanford  University, 
California,  is  one  of  the  contributing 
artists  from  the  Golden  West.  Others 
include  Walter  Hartley  of  Pomona 
College,  California;  Allan  Bacon,  College 
of  the  Pacific  at  Stockton,  California. 
The  tall  corn  country  is  represented 
by  Marshall  Bidwell  of  Coe  College, 
Cedar  Rapids,  Iowa;  the  midwest  by 
Palmer  Christian,  organist  of  the  Uni- 
versity of  Michigan  at  Ann  Arbor; 
Western  New  York  brings  Hugh  Porter, 
organist  of  the  Chautauqua  Institution 
Summer  School;  while  central  New 
York  presents  Harold  Glesson  of  the 
Eastman  School  at  Rochester.  Western 
Pennsylvania  will  be  represented  by 
Charles  Heinroth,  organist  of  the  Car- 
negie   Institute,    Pittsburgh. 

Well  Known  Amateur  Goes 
Into  Business 

F.  J.  Marco,  formerly  associated  with 
the  Bremer-Tully  Manufacturing  Co., 
of  Chicago,  has  gone  into  business  for 
himself  as  a  consulting  radio  engineer,  lo- 
cated at  5723  Winthrop  Ave.,  Chicago,  111. 

Many  amateurs  will  remember  Mr. 
Marco  as  one  of  the  old  time  operators  at 
9ZN  and  actively  engaged  in  the  "ham" 
game  in  the  old  days. 


Bulb  Extra 
At  your  dealer's.     If  he  cannot  supply 
you  send  his  name  with  your  order  to 

YAXLEY  MFG.  CO., 

Dept.  E,  217  No.  Desplaines  St.,  Chicago 


RADIO  AGE /or  December,  1025 


Radio  Foundation,  Inc., 

Has  Double-Toroid  Coil 

A  set  of  Double-toroids,  manufactured 
by  the  Radio  Foundation,  Inc.,  has  been 
received  by  Radio  Age  and  put  through 
tests  in  the  laboratory. 

In  the  coils  referred  to  above  the 
primary  and  secondary  are  both  true 
toroids  and  can  be  effectively  used  in 
any  of  the  tuned  r.  f.  combinations  now 
so  popular.  On  account  of  the  form  of 
winding,  the  toroid,  it  is  possible  to  shield 
receivers  using  these  coils,  without  sacri- 
ficing too  much  efficiency. 

The  Foundation  also  has  marketed  a 
no-noise  variable  grid  leak  using  a  liquid 
medium  and  a  semi-coiled  contact  wire. 


The  Magazine  of  the  Hour 


75 


[ROPE-CORE 


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76 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


RADIO  AGE  ANNUAL  FOR 
1924— AT  SPECIAL  PRICE! 

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1                                           1 

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L__     __     ___     __J 

Christmas  on  the  Air! 

— are  Your  Tubes  In  Shape? 

At  Christmas  Tide!  Listen  to  sweeter  "Christmas 
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Radio  and  Electrical  Products 
504     E.     Woodbridge  Detroit,     Mich. 


Grid  Leak  and  Condenser 
Now  Combined 

One  of  the  improvements  in  radio 
devices  brought  out  this  season  is  the 
new  Daven  "Leakandenser,"  an  unique 
device  which  combines  in  a  most  at- 
tractive form,  a  grid  leak  and  a  grid 
condenser.  The  Leakandenser  attracted 
considerable  attention  at  the  recent  New 
York  Radio  Show.  It  is  similar  in  size 
and  shape  to  the  conventional  cartridge 
type  of  grid  leak,  with  metal  end  caps, 
and  may  be  mounted  conveniently  in  the 
set  by  means  of  two  spring  clips  supplied 
with  the  unit. 

In  construction  it  consists  of  a  hollow 
bakelite  spool,  within  which  a  Daven 
grid  leak  is  suspended.  Each  end  is 
threaded  and  fits  into  a  nickel  plated 
terminal  cap.  Around  the  outside  of  the 
spool,  and  connected  to  the  end  caps,  is 
the  grid  condenser,  which  is  formed  by 
two  separate  and  insulated  wires,  wound 
parallel  in  a  single  layer.  One  wire 
connects  with  one  terminal  and  the  other 
with  the  other  terminal;  each  wire  of 
course  having  its  other  end  open.  There 
being  no  physical  contact  between  the 
two  wires,  they  form  a  condenser,  the 
capacity  of  which  has  been  designed  to 
be  just  right  to  function  properly  as  a 
grid  condenser. 

Grid  condensers  in  the  past  have  been 
criticised  for  their  lack  of  uniformity  in 
capacity,  their  susceptibility  to  injury 
during  soldering  operations  and  the 
tendency  to  alter  in  capacity  under 
various  conditions  after  installation. 
These  troubles  have  been  remedied  in  the 
new  Daven  unit  by  the  unique  method 
adopted  to  obtain  the  condenser  effect. 
Leakandensers  are  made  with  five  dif- 
ferent values  of  grid  leak — 2,  3,  4,  5,  or  7 
megohms,  so  that  a  selection  may  be 
made  suitable  for  any  detector  tube.  The 
Leakandenser  takes  up  less  space,  is 
infinitely  easier  and  more  convenient  to 
install,  and  makes  the  set  look  better. 


New  "A"  Power  Unit 
Made  by  Gould 

The  Gould  Storage  Battery  Company, 
250  Park  Avenue,  New  York,  are  now 
placing  on  the  market  a  highly  perfected 
"A"  power  unit  which  they  term  Uni- 
power. 

It  is  not  a  battery  eliminator  but  is 
an  "A"  power  unit  that  automatically 
converts  house  lighting  current  into 
radio  power  of  constant,  full  voltage. 
It  is  a  single  compact  unit,  enclosed  in  a 
beautifully  finished  gas-tight  case  that 
fits  comfortably  and  safely  inside  most 
radio  cabinets.  There  are  no  tubes, 
bulbs,  lamps  or  working  parts  that  re- 
quire   frequent    replacement. 

A  single  master  control  switch  operates 
both  the  radio  set  and  Unipower.  When 
the  radio  set  is  on,  the  house  current  is 
off — when  the  set  is  off,  the  house  cur- 
rent   is   on. 

It  is  impossible  to  damage  Unipower 
through  the  failure  to  add  water  when 
necessary.  When  this  happens,  the 
charger  automatically  cuts  off  and  pre- 
vents harm  to  the  battery  unit.  Uni- 
power is  supplied  in  the  models  for  60- 
cycle,  110-125  volt  A.  C.  Each  model 
is  equipped  with  a  Baklite  charger  of 
special  design.  Models  are  also  made 
of  the  25-50  cycle  lines. 

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January  Model  Receiver 

Will  Be  a  Revelation 
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CONDENSERS 
VERNIERS 
RHEOSTATS 

AMSCO   PRODUCTS.  Inc.  New  York  City 


EFFICIENCY 

That   Meet8    the  Require- 
ments of  Eminent 
Radio  Engineers 

Apex  Vernier  Dials  are  more 
than  mere  "knobs."  In  reality 
they  are  instruments  endowed 
with  an  ultra  degree  of  effi- 
ciency. Their  rich  elegance  of 
finish  lends  a  touch  of  striking 
attractiveness  to  any  set.  Pre- 
cision of  production  and  of 
operation  makes  a  good  set  a 
better  set — providing  greater 
range  of  selectivity — positive- 
ness  of  control — and  utmost 
simplicity  of  tuning  in  most 
difficult  stations.  Ratio  12  to  1. 
Clockwise  and  counter  clock- 
wise. No  back  lash.  Royal 
Brass  finish  4-inch  $1.50 — 3Vi- 
inch  $1.25.  Satin  Silver  Finish 
4-inch  $1.75— 3i/i-inch  $1.50. 
DeLuxe  Gold  (24K)  Finish  4- 
i  n  c  h  $2.50— 3Vi-i  n  c  h  $1.85. 
Your  dealer  has  them.  If  not, 
order  direct. 

APEX  Rheostat    Dials 

are  essential  to  successful  operation  and 
pleasing  appearance  as  are  Apex  Vernier 
Dials.  Royal  Brass  Finish — 60c.  Satan 
Silver  Finish— 70c.  DeLuxe  Gold  (24K)— 
80c. 

APEX    ELECRTIC     MFG.     CO. 

Dept.  1211 
1410  W.  59th  Street  CHICAGO 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


77 


A  Six  Tube 
IN  CONSOLE 

$125  LIST 

(With  Loud  Speaker) 

DIANA     "SIX" 

A  perfect  set  in  a  beautiful  cab- 
inet. A  real  six  tube  set.  Two 
models.  Cabinet  Grand  $  1 00  list. 
Console  as  shown  above  with 
loud  speaker,  $125  list.  A  long 
distance  set.  Easy  to  tune. 

Exclusive  Territory  Open 

Write  for  Liberal  Discount  and  splendid 
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request. 

DIANA  RADIO  COMPANY 

1429  So.  Michigan  Ave.,  Chicago 


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17 


Broadcast  Waves  to  Stay 
"Put"— Hoover 

WASHINGTON,  D.  C— Secretary 
"  '  Hoover  is  not  contemplating  an- 
other general  reallocation  of  broadcast 
wavelengths  or  frequencies.  Unless  a 
large  majority  of  radiodom  decrees  other- 
wise or  another  conference  recommends 
a  change,  he  is  disposed  to  leave  the 
situation  as  it  is  today  with  a  ten  kilo- 
cycle separation  between  the  radio- 
phone channels. 

Judge  S.  B.  Davis,  Acting  Secretary 
of  the  Department  of  Commerce,  who 
aids  the  Secretary  in  the  administration 
of  radio,  explained  that  the  Depart- 
ment would  not  change  the  broadcasting 
channels  again,  despite  recent  reports 
and    rumors    to    the   contrary. 

If  the  slate  were  clean,  so  to  speak, 
or  there  were  no  broadcasters  on  the  air 
today,  and  the  Department  was  about 
to  inaugurate  broadcasting,  it  would 
undoubtedly  assign  all  class  B  stations 
wavelengths  separated  by  fifteen  kilo- 
cycles, limiting  the  number  of  stations 
which  might  broadcast  and  insuring 
better  reception  for  all,  but  unfortunately 
this  is  not  the  case;  there  are  563  stations 
on  the  air  and  more  clamoring  to  open. 
During  its  recent  experiments,  the 
Department  experts  tried  to  create 
additional  wavelengths  by  decreasing 
the  separations  to  seven  kilocycles,  only 
to  find  that  the  spaces  were  too  narrow 
between  the  wave  channels  to  insure 
good  reception  and  minimum  inter- 
ference. So  the  plan  was  given  up. 
The  Departmental  Officials  realize 
that  transmission  and  reception  would  be 
better  if  the  wave  channels  were  fifteen 
kilocycles  apart  instead  of  only  ten, 
but  if  greater  separation  between  the 
stations  was  made,  congestion  and 
consequently  interference  would  soon 
be  worse.  That  is  the  one  thing  these 
radio  experts  wish  to  avoid.  If  the  83 
Class  B  stations  were  assigned  new 
wavelengths  with  a  separation  of  fifteen 
meters,  there  would  be  fewer  broad- 
broadcasting  routes;  some  stations  would 
have  to  get  off  the  air  or  divide  time 
further  with  each  other.  There  are  only 
47  channels  available  for  the  83  B  broad- 
casters, which  requires  that  they  double 
up.  Actually  68  are  now  splitting  time, 
and  there  are  still  applications  for  Class 
B  privileges  on  file.  Fans  would  soon 
raise  a  cry  of  protest  if  some  of  the 
nationally  known  efficient  stations  which 
put  out  high-class  programs  were  made 
to  share  their  wavelengths  or  time  with 
inferior    or    new    broadcasters. 

The  broadcast  wave  band  from  545 
to  205  meters  cannot  well  be  extended 
upward,  else  it  would  interfere  with  the 
"SOS"  marine  distress  call  on  600 
meters;  if  pushed  further  downward, 
it  would  encroach  upon  the  band  assigned 
to  the  amateurs,  who  have  already  been 
ousted  from  their  original  channels. 

But  there  is  another  reason  why  the 
broadcast  band  cannot  be  widened; 
it  is  on  account  of  the  limits  of  average 
radio  receiving  sets,  many  of  which, 
although  rated  as  capable  of  receiving 
on  any  wave  between  600  and  200  meters, 
are  not  efficient  at  both  extremes. 
*    Tested  and  Approved  by  RADIO  AGE    * 


Every  Tube 
•f  Full  of  Life! 

What  a  wonderful  difference  AMPER- 
ITE  makes  !  Every  tube  is  so  brimful  of 
snap,  so  eager  to  deliver  100%  value.  In- 
dividual tube  regulation  to  meet  each 
tube's  individual  needs  is  the  answer. 
And  only  AMPERITE  can  fill  that  re- 
quirement. Permits  the  use  of  any  type 
or  combination  of  tubes.  Specified  in  all 
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There  is  an  AMPERITE  for  every  tube 
Write  for  free  hook-ups 

r^r^idiaU  Gompany 

'  Dept  R.  A.-12,  50  Franklin  St.,  N.  Y.  City 


Oke  "SELF-ADJUSTING" Rheostat 


Amperite 

No.  1  A 

Used  in  the 

Radio  Age 
Model  Receiver  "H" 

Featured  in  this  issue 

See   Page  7 


Storage  "B"  Battery 

11  volti    Lasts  Indefinitely— Pays  for  Itself 

Economy  and  performance  unheard  of  before.    Recharged 
at  a  negligible  cost.     Approved  and  listed  as  Standard  by 

eading  Radio  Authorities,  including  Pop.  Radio  Laboratories,  Poo. 
Sci.  Inst.  Standards,  Radio  New§  Lab.,  Lefax,  Inc..  and  other  im- 
portant institutions.  Equipped  with  Solid  Rubber  Case,  anlnanr- 
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rugged  places     Order  yoora  today! 

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Pay  expressman  after  examining  batteries.  6  per  cent  discount  lor 
cash  with  order.    Mall  your  order  nowl 

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78 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


Non-Vibrant  Ceramic 
Horn 


For  EVERY 
Radio  Set 

A  stunning  piece  of  furniture  that 
restores  order  in  the  room  where 
you  have  your  Radio!  No  more 
cluttered  table-tops,  nor  litter  of 
equipment  un- 
der-foot. 

No  unsightly 
horn  in  evidence, 
either!  This  con- 
sole has  its  own 
loudspeaker,  in- 
built. It's  out  of 
sight,  but  with 
very  apparent 

tonal  SUperior'l-  The  clearest  tone  pro- 
4-',r*r.        T?~-    '.*-    1  „~     ducer  on   the   market. 

ties,    tor  it  has   Made  of  specilll  com. 

the     highest -de-     Position  which  defeats 
,  j  r    vibration. 

veloped  type  or 

unit.  With  horn  built  of  special 
non-vibrating, extra-hard, ceramic 
material.  Produces  clear  non-vi- 
brant tone. 

There's  ample  room  for  every- 
thing; space  for  largest  A  and  B 
wet  batteries  —  or  battery  elimi- 
nator—required for  any  home  set; 
and  for  a  big  charging  outfit,  too. 

Finished  in  mahogany,  or  walnut  color. 
Dainty  design  of  parqueterie  on  two  front 
panels.  Top,  38  in.  x  18  in.  Substantially 
built;  the  product  of  a  40-year-old  furni- 
ture maker. 

The  price,  forty  dollars,  is  for  the  complete 
console  and  includes  the  loudspeaker  horn 
and  unit.  Thousands  of  dealers  are  show- 
ing this  artistic  addition  to  home  radio 
equipment. 

Rear  View— Set  Hooted  Up 


The  New  Word  in  Radio 

In  radio,  "kilocycle"  is  gradually  tak- 
ing the  place  of  "wavelength"  says  the 
Bureau  of  Standards,  Department  of 
Commerce.  All  listeners  and  users  of 
sets  will  want  to  know  and  understand 
the  new  rating  which  increasingly  gov- 
erns their  tuning  in.  The  making  or 
logging  of  dials  is  found  to  have  certain 
advantages  when  in  the  newer  terms. 
Already  one  of  the  oldest  stations  is 
announcing  its  broadcasts  on  the  "kilo- 
cycle" or  frequency  rating.  It  is  really 
quite  simple,  for  frequency  (waves  per 
second)  replaces  wavelength  (in  meters). 

Just  as  a  musician  can  vary  the  number 
of  oscillations  of  his  vocal  chords  but 
cannot  control  the  length  of  the  sound 
waves,  which  vary  with  the  medium, 
so  a  radio  station  can  vary  the  number 
of  oscillations  per  second,  and  let  the 
wavelengths  be  what  they  will.  A  high 
tenor  "C"  gives  sound  waves  2  feet  in 
length  but  the  standard  rating  is  fre- 
quency, or  pitch,  in  this  case  512  vibra- 
tions per  second.  Frequency  is  the  num- 
ber of  waves  produced  per  second,  the 
number  of  waves  on  the  air  after  one 
second  of  transmission.  "Kilocycle" 
means  a  thousand  cycles,  hence  a  broad- 
cast on  a  500-kilocycle  frequency  emits 
500,000  radio  waves  per  second. 

To  aid  radio  amateurs  and  experts  the 
Bureau  of  Standards  is  about  to  issue  a 
table  so  that  all  can,  at  a  glance,  tran- 
slate from  the  old  rating  by  "wavelength" 
(in  meters)  into  the  new  rating  by  fre- 
quency (in  kilocycles),  and  vica  versa. 
Radio  waves  travel  with  the  speed  of 
light,  about  300,000  kilometers  per 
second.  This  is  the  sum  of  all  the  waves 
emitted  in  one  second.  Dividing  this  by 
the  wavelength  gives  the  frequency; 
dividing  by  the  frequency  gives  the  wave- 
length. 

The  bureau  gives  the  simple  rule  to 
obtain  the  frequency  when  the  wave- 
length (in  meters)  is  known :  Divide 
300,000  by  the  wavelength  in  meters. 
The  answer  is  in  kilocycles.  Likewise 
the  other  way  around;  divide  300,000 
by  the  number  of  kilocycles  to  get  meters. 
It  is  interesting  that  the  ratio  is  the  same 
both  ways;  100  meters  equals  3,000 
kilocycles;  100  kilocycles  is  3,000  meters. 


Inexpensive  Tube  Test 

Set    Made    by    Jewell 

An  interesting  booklet,  known  as  15-A 
has  just  been  issued  by  the  Jewell  Elec- 
trical Instrument  Co.,  of  Chicago,  for 
the  information  of  the  radio  trade  and 
experimenters. 

The  Jewrell  Company  has  placed  on 
the  market  a  simple  tube  tester,  known 
as  Pattern  110,  which  should  meet  the 
demand  for  an  inexpensive  tube  test  set 
desired  by  many  of  the  experimenters 
in  the  game,  as  well  as  the  dealers.  It  is 
fully   described   in   the    15-A   booklet. 


New  Coils 
New  Condensers 
Easier  Control 
Watch  for  the  January- 
Radio  Age  Model  Set 


All  — 

Stand;  rd  *X*    ™ 

Types  <»     ~ 

$2.50  E 


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■/////////////////////////St*. 


■'S////////////////S///S, 


ED  ilQW  RADIO  TUBES 


f/ 

™  Cleartron  is  the  only  radio    S 
5  tube  sold  under  an  Iron-Clad    ! 
S  Guarantee  of  perfect  service    g 
I"  or  instant  replacement. 

->»  At  All  Reliable  Dealer!.  JJ 

—  Write  for  Free  six  pact  tube  folder.  mm 
™  Hi-Contlrofl  Model  C-T  101A— 83.00.  The  mm 
«■  original  Hi-Mu  Tube  for  Resistance-Coupled  JJ 
J^  Amplifiers.  ^» 

2      CLEARTRON  VACUUM  TUBE  COMPANY        = 

—  Executive  Offices.  kftj  « 
~  28  West  44th  Street,         New  York  City.  — 

—  Factories:     West  New  York,   N.  J..    U.  S.  A.  

Birmingham.  Eno.  

iiiiimmiiiiiiiiiiiiiiiiiiiiiiiiiiii 
For  Better  Keception 
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*    Tested  and  Approved   by   RADIO   AGE    * 


THE  ACCURATUNE 
is  ideal  for  coarse  or  ex- 
tremely fine  tuning,  segre- 
gating even  those  stations 
now  so  closely  grouped  on 
the  lower  wave  lengths;  it 
brings  them  in  with  ab- 
solute precision.  Volume 
and  clarity  are  matters  of 
course  to  the  Accuratune. 
Quickly  substituted  with- 
out alteration  of  your  set. 

MYDAR  RADIO  CO. 
17  CAMPBELL  ST.,  NEWARK,  N.  J. 


Accuratune 


RADIO  AGE  for  December,  1925 


The  Magazine  of  the  Hour 


79 


CLASSIFIED  ADVERTISEMENTS 

If  you  have  anything  to  buy  or  sell,  don't  overlook  the  value  of  RADIO  AGE'S  classified 
advertisements.    Many  such  messages  have  paved  the  way  to  independent  incomes. 

The  classified  advertising  rates  are  but  ten  cents  per  word  for  a  single  insertion.  Liberal 
discounts  are  allowed  on  three,  six  and  twelve-time  insertions,  of  five,  fifteen  and  thirty  per  cent 
respectively.  Unless  placed  through  an  accredited  advertising  agency,  cash  should  accompany 
all  orders.  Name  and  address  must  be  included  at  foregoing  rates  and  no  advertisement  of  less 
than  ten  words  will  be  accepted. 

All  classified  ads  for  the  January  issue  must  be  sent  in  by  December  1. 


ADVERTISING     SERVICE 


QUEX    Sales    Letter.    Get    More    Business. 
today.      Quel,  4418  Michigan  Ave.,  Chicago 


AGENTS  WANTED 


FORDS.  60  miles  on  one  gallon  of  Gas.  It  has  been 
pi-OTen  such  mileage  can  be  made.  AIRLOCK  guar- 
antees to  increase  gas  mileage;  also  prevents  radiator 
boiling  in  summer  or  freezing  in  winter.  Cools,  Fuels, 
Decarbonizes  the  Ford  motor.  Splendid  territory 
open.  AIRLOCK  PRODUCTS,  Box  703G,  Willow  Street, 
Long  Beach,  Calif. 


RADIO — Join  our  sales  organization  and  make  big 
money.  We  want  a  man  in  every  county  to  sell  well 
advertised  sets  and  parts  made  by  the  leading  manu- 
facturers. Widener  of  Kansas  City  makes  $150.00 
weekly.  You  can  do  aa  well  or  better.  Write  today 
for  catalog,  and  discounts.  Name  your  county.  Wave- 
land  Radio  Company,  Div.  52,  1027  No.  State  St.,  Chi- 
cago, III. 


MANUFACTURER'S    AGENT 
tries  1  Jobbers,  Chicago  and  vi 
additional  lines  carrying  volu 
to    large    jobbers.       Edelstein, 
Chicago. 

calling    on    Radio 

trinity ,  has  opening 

ne  business,  as  we 

1804    McCormick 

Elec- 
for  3 
cater 
Bid., 

Man  wanted  for  this  territory  to  sell  wonderful 
value  men's,  women's.  Children's  shoes  direct,  Hav- 
ing consumer  over  40%.  Experience  unnecessary. 
Samples  supplied.  Big  weekly  permanent  income. 
Write  today  Tanners  Mfg.  Co.,  1334C.  St.,  Boston,  Mass. 


AGENTS— 90c  AN  HOUR  TO  ADVERTISE  AND  Dis- 
tribute samples  to  consumer.  Write  quick  for  territory 
and  particulars.  American  Products  Co.,  4202  American 
Bldg.,  Cincinnati,  Ohio. 


"B"    BATTERIES 


100  VOLT  EDISON  TYPE  "B"  BATTERY,  knocked 
down.  Parts  and  plam — complete,  $12.50.  Lane  Mfg. 
2937  W.  Lake,  Chicago. 


BATTERIES  FOR  SALE — Four  24-volt  "Main"  Storage 
"B"  Batteries,  never  used,  shipped  and  ready  to  wire 
for  $38.00.  First  order  gets  the  batteries.  Address 
Bom  B,  Radio  Age,  500  N.  Dearborn  St.,  Chicago,  111. 


BUSINESS  OPPORTUNITIES 


$100  weekly  up.  We  want  experienced  Radio  men  to 
operate  branch  assembling  plants.  Part  or  whole 
time.  Barfield  Radio  Co.,  13  Tillery  Street,  Dept.  A  R, 
Brooklyn,  New  York. 


Quick,  steady  profits  assured  from  the  s 
a  real  chance  to  make  big  money  in  radio  this  season. 
Write  for  details,  at  no  obligation.  KELLY  RADIO 
SUPPLY  CO.,  3312  Warren  Ave.,  Chicago,  III.,  Box  11B. 


Classified  ad.  copy  for  the  Jan- 
uary RADIO  AGE  must  be  sent 
inby  December  1,  1925. 


CRYSTALS 


Supersensitive  Galei 
ALKEMITE.  Allse 
Geologist,  Joplin,  M: 


HELP  WANTED 


RADIO  SALESMEN  and  SET  BUILDERS— We  need 
you  and  you  need  us.  If  you  ere  reliable  and  well 
known  in  your  community,  we  will  appoint  you  our 
representative  and  furnish  you  with  standard  well 
advertised  sets  and  parts  at  prices  that  will  enable  you 
to  sell  at  a  handsome  profit.  Write  at  once  for  cata- 
log and  sales  plan.  Waveland  Radio  Co.,  Div.  53,  1027 
N.  State  St.,  Chicago,  III. 

MEN  wanting  forest  ranger,  railway  clerk  and  other 
government  positions,  write  for  free  particulars  of 
exams.      Mokane,    Dept.    B-33.    Denver,  Colo. 


MEN  WISHING  TO  ENTER  DINING,  SLEEPING  CAR 
SERVICE  AS  CONDUCTORS,  PORTERS,  WAITERS, 
WRITE  123  RAILWAY  EXCHANGE,  KANSAS  CITY. 


INVENTIONS 


NEW  IDEAS  WANTED— Well  known  Radio  Manufac- 
turer whose  products  are  nationally  advertised  and  sold 
everywhere  wants  new  Radio  device  to  eel).  Will  p*ay 
outright  or  royalty  for  idea  or  invention  which  is  really 
new  and  saleable.  Address:  Mr.  R.  F.  Devine,  Room 
1101,  116  West  32nd  St.,  New  York,  N.  Y. 


PATENTS 

FOR  SALE:     U.  S.  and  Canadian  Patent  on  an  Attach. 
merit    For   Phonographs;    is    the  most   beautiful    inven- 
tion of  the  age.     Address  Chas.  F.  Smith.  Huff,  N.  Dak. 

PRINTING 

WE 

San 

print 
■  pies. 

Stat 
Com 

z 

cry.    Booklets,    Ca 
rcial  Press,  Batavii 

talogs, 
,  Ohio 

Circulars. 

RADIO 

A  PRACTICAL  TUBE  RECEIVING  SET  FOR  $10, 
Postpaid,  leas  phones  and  tube.  Complete  with 
phones,  tube  and  battery.  $16.00.  J.  B.  RATHBUN, 
1067  Winona  St.,  Chicago,  111. 

Standard  soderless  radio  Jacks.  Binding  post  attach- 
ments. Double  circuit.  One  dollar  bill.  Postpaid. 
Clinton  Seward,  Jr.,  New  Paltz,  New  York,  N.   Y. 

Three  Cosmopolitan  Phusiformers.  each  $5.50,  book  of 
instructions  included.      F.  A.   Mall,   Triopli,    Iowa. 


15  to  25  per  cent  discount  on  nationally  advertised  sets 
and  parts.  Every  item  guaranteed.  Tell  us  your  needs. 
IMPERIAL  RADIO  COMPANY,  Delaware,  Ohio. 

RADIO  SETS.  Our  prices  save  you  money.  Lists  free. 
The  Radio  Shoppe,  Box  645,  East  Liverpool,  Ohio. 

AT  LAST  I  The  Radco  Static  Eliminator.  Eliminates 
50  to  90%  Static.  Many  satisfied  users.  Write  for 
particulars.  Radio  Specialties  Company,  Sioux  Falls, 
South    Dakota. 

$1.00  For   Your  Old  Tubes 
regardless  of  make  or  condition  towards  the  purchase 
of  each  new  Standard  $2.50  tube.     Positively  guaranteed. 
We  do  not   sell  rebuilt  or  bootleg   tubes.      Order   today. 
Luxem   &  Davis  Mfg.   Co.,  6229  Broadway,   Chicago,   III. 


RADIO  CIRCUITS 


SPECIAL  FOR  NOVEMBER 
The  Reinartz  Radio  Booklet,  by  Frank  D.  Pearne,  fully 
illustrated,  and  RADIO  AGE,  for  $2.50.      Price  of  Book- 
let alone  is  50c.      Send  check,  currency  or  money  order 
to  RADIO  AGE,  500  N.  Dearborn  Street,  Chicago. 


RADIO  DEALERS 


DEALERS— Write  for  our  illustrated  catalog  of  reliable 
Radio  Merchandise.  Rossiter-Manning  Corporation. 
Dept.  D,  1830  Wilson  Ave.,  Chicago,  111 


RADIO  SUPPLIES 


HAVE  YOU  SEEN  THE  NEW  DIALITE,  THE  UNIQUE 
lamp  that  lights  up  your  panel  and  adds  a  decorative 
touch  to  any  radio  set?  Retails  at  $2.75,  complete. 
Send  for  folder  and  dealer's  proposition  on  this  fast 
moving  article.  Also,  we  are  distributors  for  the  famous 
Knurled  Walnut  Cabinets,  the  most  beautiful  cabi- 
nets made.  American-Universal  Radio  Co.,  6255 
Broadway,  Chicago,  III.,  Box  11. 


SALESMEN  WANTED 


Make  $100  WEEKLY  in  spare  time.  Sell  what  the 
public  wants — long  distance  radio  receiving  sets.  Two 
sales  weekly  pays  $100  profit.  No  big  investment, 
no  canvassing.  Sharpe  of  Colorado  made  $955  in  one 
month.  Representatives  wanted  at  once.  This  plan 
is  sweeping  the  country — write  today  before  your 
county  is  gone.  UMRKA,  INC.,  126  F  Austin  Ave., 
Chicago. 

STAMPS,  50  varieties,  Africa,  Brazil,  Peru,  Cuba, 
Mexico,  etc.,  10c.  50  different  U.  S.,  25c;  1,000  mixed, 
40c;  1,000  hinges,  10c.  List  free.  C.  Stegman,  5950 
Cote  Brilliante,  St.  Louis,  Mil 


MANUFACTURERS  OF  NEW  AND  IMPROVED  STA- 
tion  finder  and  vernier  tuning-dial  want  live  salesmen 
to  call  on  radio  trade.  Excellent  side-line;  good  com- 
missions; exclusive  territories.  Westerland  Corpora- 
tion, Dobbs  Ferry,  New  York. 


WANTED 


WANTED— To  complete  my  set  RADIO  AGE  need 
August,  September,  October,  November,  1923,  issues, 
bound  or  unbound.  Advise  price.  Lloyd  C.  Henning, 
Hollbrook.  Arizona. 


WIRELESS 


WANT  TO  MEMORIZE  THE  WIRELESS  CODE?  The 
Coryden  Snyder  Code  Method,  Patented,  is  quickest. 
Send  50c  coin,  stamps  or  M.  O.  to  C.  G.  Snyder.  1423 
Elmdale  Ave..  Chicago.  111. 

TELEGRAPHY— Morse  and  Wireless— taught  at  home 
in  half  usual  time  and  at  trilling  cost.  Omnigraph 
Automatic  Transmitter  will  send,  on  Sounder  or  Buz- 
zer, unlimited  messages,  any  speed,  just  as  expert 
operator  would.  Adopted  by  U.  S.  Govt,  and  used  by 
leading  Universities,  Colleges,  Technical  and  Telegraph 
Schools  throughout  U.  S.  Catalog  free.  Omnigraph 
Mfg.  Co.,  13  F  Hudson  St.,  New  York. 


PERSONAL 


LONELY  HEARTS: 
new  friends  in  ou 
Jacksonville,  Flork 


Exchange  letters;  make  interesting 
'  jolly  club.  Eva  Moore,  Box  908, 
a.    Enclose  stamp. 


Look!  You  Radio  Bugs!  Join  Radio  Correspondence 
Club.  Entirely  new.  Broaden  your  acquaintance, 
exchange  ideas.  Membership  open  to  LADY  BUGS 
also.  Dime  stamp  brings  pamphlet  and  Radio  Novelty 
Cards.     Radio  Rose,  Box  662,  Cleveland,  Ohio. 


WRITERS 


Make  big  money  writinff  Movie  Plays- 
W.    C.    Krug,    Ashton,    Illinois. 


Radio  Age   Classified  Ads   Bring  Results 


»     Tested  and  Approved  by  RADIO  AGE     * 


80 


RADIO  AGE  for  December,  1925 


Bteinfte  toss 

Interference  Eliminator 

No  Radio  Set  Complete  Without  It 

Now  you  can  Belect  stations  at  will,  cat  out 
interference  and  undesired  stations— tune 
in  loud  and  clear.  Wonderful  results  with  any 
tube  or  crystal  set  using  any  kind  of  aerial  ex- 
cept loop  antenna.  Partially  absorbs  static. 

Amazing  Re- 
sults, Better 
Reception 

Guaranteed  or 

We  Refund  Your 

Post-  Dollar.  Send 

paid.  Order  Today 

Select  Stations  At  Will 

Try  this  Interference  Eliminator  on  yonr  set— 
no  tools— nothing  to  add  — attached  in  2  minutes 
to  aerial.  Doesn  t  disturb  present  log.  Direc- 
tions easy  to  follow.  Two  big  banks  testify  to 
our  reliability.  Order  today— dollar  bill  will  do— 
we  take  the  risk— money  back  if  you  say  so. 

STE1NITE   LABORATORIES 

302  Radio  Building.  ATCHISON,  KANSAS 

Write  for  complete  Steinite  Radio  literature— 
it*s  FREE.  Most  beautiful  and  least  expensive 
radio  sets  in  America. 


To  the  Man  with  an  Idea 

I     offer    a     comprehensive,    expe- 
rienced     efficient     service    for     his  , 
prompt,    legal    protection    and    the 
development   of   his    proposition. 

Send  sketch  of  model  and  de- 
scription, for  advice  as  to  cost, 
search  through  prior  United  States 
patents,  etc.  Preliminary  advice 
gladly  furnished  without  charge. 

My  experience  and  familiarity 
with  various  arts  frequently  en- 
able me  to  accurately  advise  clients 
as  to  probable  patentability  before 
they   go   to   any   expense. 

Booklet  of  valuable  information  and 
form  for  properly  disclosing  your 
idea  free  on  request.     Write  today. 

|  RICHARD  B.  OWEN,  Patent  Lawyer 

81  Owen    Bldg.,  Washington,  D.  C. 
2278-M  Woolworth  Bldg.,N.  Y.  City 


MARVELOUS  NEW 
AUDIO  TRANSFORMER 

adds  a  musical  aualityto  any  est  far 
beyond  anything  you  ever  heard 
before. 

KARAS  HARMONIK 

Amplifies  low,  middle  and  high 
tones — allto  the  same  big  volume, 
thus  eliminating  distortion.  Brings 
out  the  vita  harmonics  and  over, 
tones  of  music.  Price  $7.00.  Write 
Karas  Electric  Co.,    Depl.  58-93    4042  N.  Rockwell  Si.    Chicago 


MASTERTONE 
RADIO  TUBES 

ALL  TYPES  GUARANTEED 

Dealers'  Proposition 

Dextron  Radio  Lab. 

74  Sterling,  Dept.  R.  A. 

East  Orange,  N.  J. 


2 


00 


— Radio  Nut's  Headquarters — Parts  only,  no 
sets.  $20,000  stock.  Most  comprehensive.  If 
you  can't  find  it,  ask  us.  Weekly  latest 
"dope" — 10  wks.  50c.  "Change  your  Neut" 
Ki t — $5  prepaid.  Particulars — 1 0c.  48  page 
parts  catalog — 10c.  Knock  Down  Loop  Kit — 
$7.50.  150  v.,  55  milamp  B  Eliminator,  off 
110  v.  a.  c,  knock  down  kit  including  2000 
hr.  Z  50  tube — $36.55.  Assembled,  ready  to 
uae — $40.  Data — 10c.  Kladag  Radio  Labora- 
tories),   Kent,    Ohio. 


Fourth  Chicago  Radio  Show, 
Nov.  17-22 

(  Continued  from  page  73) 

The  fourth  annual  Chicago  Radio 
Show  is  the  official  show  of  the  Radio 
Manufacturers'  Association,  and  it  is 
expected  dealers  and  jobbers  from  as  far 
west  as  the  Pacific  coast  will  be  on  hand 
to  make  the  acquaintance  of  the  big  men 
of  the  industry  who  will  be  present  at 
this,  the  biggest  radio  show  and  gathering 
of  manufacturers,  dealers  and  jobbers 
ever  held  in  the  middle  west. 

New     York's    1926    Radio    Show 
In  Bigger  Quarters 

The  radio  industry  next  year  will  have 
its  annual  New  York  show  in  the  finest 
exposition  palace  in  America,  according  to 
Maj.  Herbert  H.  Frost,  president  of  the 
Radio  Manufacturers'  Association.  A 
lease  has  just  been  signed  on  the  new 
Madison  Square  Garden  and  Exposition 
Hall,  now  nearing  completion  as  the 
successor  to  the  famous  old  Madison 
Square  Garden. 

The  radio  show  will  occupy  the  entire 
two  floors  of  the  new  structure.  The 
larger  exhibits  will  be  displayed  in  the 
Grand  Arena,  285  feet  long  and  110 
feet  wide.  This  floor  is  larger  than  the 
old  Garden.  The  Exposition  Hall, 
376  feet  long  and  200  feet  wide,  built 
expressly  for  the  housing  of  the  largest 
trade  shows,  will  also  be  used.  This  will 
make  in  all  a  total  of  about  102,000  square 
feet  of  exhibition  space.  The  rental  is  the 
highest  ever  paid  by  a  trade  show. 

This  tremendous  space  will  be  neces- 
sary because  all  the  leading  manufac- 
turers are  centering  on  this  show,  the 
industry  being  opposed  to  the  holding  or 
more  than  one  show  in  each  city  each 
year.  Heretofore  there  have  been  two 
shows  annually  in  New  York. 

Amateurs  Help 

Minneapolis,  Minn. — The  Twin  Cities 
Radio  Club,  a  joint  organization  of 
transmitting  radio  amateurs  of  this  city 
and  St.  Paul,  served  in  a  helpful  capacity 
during  the  recent  Twin  Cities  Radio 
Show,  when,  during  the  course  of  the 
show  they  handled  over  700  messages 
from  patrons  of  the  show.  These  mes- 
sages were  started  on  their  way  to  all 
parts  of  the  United  States  via  the  medium 
of  American  Radio  Relay  League  mem- 
ber stations.  The  Twin  Cities  club  is 
allied  with  the  League. 


The  January  Radio  Age 
Model  will  Be 
Easier  to  Build 


The  Magazine  of  the  Hour 


WRS  96-PAGE 

RADIO  GUIDE  BOOK 

Profusely    illustrated, 

'  'cboekful"  of  data  for  the 

radio  fans . 

Trouble  Shooting  Chart. 

Complete  New  List  of 

Broadcasing  Stations 

Log   Chart 

— and     details    of     newest 

ipparatus  and  hundreds  of 

Exceptional 
Radio  Values  our 
MONEY  BACK  GUARANTEE 

From  bus  bar  to  the  finest  multi-tube  set,  we  carry  one  quality— 
THE  FINEST!  EVERY  article  represents  100  cents  worth  of 
value  for  every  dollar  you  invest!  EVERYTHING  purchased 
from  WRS  is  guaranteed:  Yonr  Money  is  still  YOUR  Money  un- 
til! you  are  thoroughly  satisfied  in  every  way. 

WRS  IS  HEADQUARTERS  FOR  KITS  AND  SETS 


Cockaday  Super 
Cockaday  D.  X. 
Ultrodyne 
Roberts'  Knock-Out 


EVERY 
STANDARD 
RECEIVER 


Neutrodyne 

Superdyne 
Pressley  Super 
Rasla 


WHOLESALE  RADIO  SERVICE  CO. 
6  Church  St.     Cat.  R.  A.  10,     New  York  City 


''a  new  5-Tube  Set 
with  all  the  power 
and  none  of  the 
grief  of  the  Superi" 

— so  wrote  Henry 
M.  Neely.  Editor  ol 
Radio  in  the  home, 
Philadelphia 


Get  This  Book 

Write  today  for  this  big  fascinating 
32-page  booklet  which  tells  how  you 
can  build  the  truly  amazing  new 
QUADRAFORMER  receiver 
Based  on  a  new  radio  principle, 
five  tubes  give  remarkable  results. 

Enclose  10c  and  you'll  have  it  by  return  mail 

Gearhart-Schlueter  Radio  Corp'n 

713  Voorman  Avenue,  Fresno,  California 


POLK'S  REFERENCE  BOOK 

FOR    DIRECT   MAIL    ADVERTISER8 

Shows  how  to  Increase  your  business  by 
the  use  of  Direct  Mall  Advertising,  60  pages 
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where  and  how  many  prospects  you  have. 
Over  8,000  lines  of  business  covered. 
Write    for   your   FEEE  copy. 

R.  L.  POLK  &  CO.,  Detroit,  Mich. 

599  POLK    DIRECTORY    BUILDING 
Branches   in   principal   cities  of  U.    S. 


*    Tested  and  Approved  by  RADIO  AGE    * 


Write  for  This 

"How  To  Build" 

Book 

You  will  find  it  surprisingly 
easy  to  build  the  Hammar- 
lund-Roberts  Receiver  from 
this  instruction  book.  Fully 
illustrated  throughout;  gives 
complete  information  on 
assembling,  wiring      c\  C  _ 


and  operation. 


Associate 
Manufacturers 

All-American  Radio  Corp. 
Alden  Manufacturing  Co. 
Radiall  Co. 
(  Amperites) 
Carter  Radio  Co. 
Union  Radio  Corp. 
Internationa  1  Resistance  Co.  Inc. 

(Durham  Resinters) 
Westinghouse  Micarla 
Hammarlund  Mfg.  Company,  Inc. 


Every  part  Designed 
by  a  Specialist 

NO  ordinary  standards  of  five-tube  reception  or  ease  of  operation  can 
be  applied  to  the  Hammarlund-Roberts  Receiver.  It  compels  so 
complete  a  revolution  in  all  previous  ideas  of  performance  and  value  that 
you  can  understand  its  sensational  results  only  through  a  personal 
experience. 

Every  single  unit  that  goes  to  make  up  this  remarkable  receiver  was  chosen 
by  a  specialist  after  months  of  research.  The  transformers  were  selected 
by  an  engineer  familiar  with  every  reliable  make;  the  condensers  by  a 
man  who  had  made  a  special  study  of  condenser  constructions  and  func- 
tions. So  it  was  even  with  the  smallest,  usually  neglected  units. 
From  the  work  of  these  engineer-designers,  backed  by  the  endorsements 
of  ten  famous  radio  parts  manufacturers,  comes  the  Hammarlund-Roberts, 
a  receiver  that  is  truly  the  ultimate  in  five-tube  possibilities.  The  equal 
of  any  standard  eight  tube  set,  in  selectivity  and  volume — so  simple  in 
design  and  operation  that  anyone  might  construct  it.  Priced  amazingly 
low,  the  Hammarlund-Roberts  offers  the  greatest  value  possibe  in  the 
radio  field  today. 


TRANSFORMER 

This  instrument  and  other  parts 
shown  are  some  of  the  famous 
units  used  in  the  Hammarlund- 
Roberts. 


* 


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HAMMARLUND-ROBERTS,   1182-D  Brcadway,  New  York 


ISslQ 


Dials  and 
Sockets 


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01 

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UNION 

The  most  efficient 
Phone    TiD   Jack. 

Switches 
and   Rhe- 
ostats 

•^r-sr^ufirT^ryl^ 

■v  DURHAM 
*  RESISTOR 

H-     Tested  and  Approved  by  RADIO  AGE     # 


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tt 


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But  It  Does  More! 


*    Tested  and  Approved  by  RADIO  AGE    * 


IB  073