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Full text of "73 Magazine (May 1976)"

MAY 1976 
$1.50 





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Closed Loop Antenna Tuning . , - , , . .32 

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How to Coax Your Antenna . .........,,,_ .40 

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A Failure to Communicate .•...-•.,.-,,,...,,.. .143 




#187 MAY 1976 



4 


Ntever Say Die 


6 


Letters 


11 


Looking West 


13 


Contests 


64 


Oscar Orbits 


64 


Hem Help 


69 


I/O Editorial 


116 


Ancient Aviator 


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New Products 


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Briefs 


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Docket 20686 


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Ham burglar 


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Readef Service 


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Propagation 



COVER: Oits on masonite, by 
Jerry W, Geiger, Dela field Wl. 



NOTICE TO RliVDERS 

IT IS A CRIMEN A L VIOLATION OF FEDERAL LAW AND OF THE LAW OF MANY STATES TO 
USE ANY INSTRUMENT, DEVICE, OR SCHEME TO OBTAIN ANY TELEPHONE SERVICE WITHOUT 
PAYMENT OF THE LAWFUL CHARGES THEREFOR. IT MAY ALSO BE A CRIME TO PROVIDE 
INFORMATION THAT IS USEFUL FOR SUCH PURPOSE UNDER CERTAIN CIRCUMSTANCES TO 
ANY PERSON, INCLUDING THE INFORMATION APPEARING IN THE ARTICLE BEGINNING AT 
PAGE 67 OF THE JUNE 1975 ISSUE OF THIS MAGAZINE. 

WE aWE BEEN NOTIFIED BY THE BELL SYSTEM THAT SUCH VIOLATIONS ARE 
VIGOROUSLY IN-VESTIGATED AND PROSECUTED. ACCORDINGLY, YOU ARE URGED TO 
DESTROY ANY DEVICES YOU MAY HAVE WHICH VIOLATE ANY OF THESE LAWS, INCLUDING 
ANY DEVICES BASED IN ANY WAY ON THE MATERIAL APPEARING BEGINNING AT PAGE 67 OF 
THE JUNE 1975 ISSUE OF THIS MAGAZINE. 

THIS STATEMENT IS BEING PUBLISHED BY ORDER OF THE SUPERIOR COURT OF THE STATE 
OF CALIFORNIA WITH THE CONSENT OF THE PUBLISHER OF THIS MAGAZINE. 



73 Magazine fwh&re the action is J is pab fished monthly by 73, inc.^ Peterborough NH 03458 ia good p face to fiveh Subscnption raWs 
are a ridicuiousiy iow $70 for one year woridwide, $17 for two years, and $17.76 for three years (the buy of the year?}. Second ci3ss 
postage paid at Peterborough NH 03458 and at additional mailing offices. Phone: 603-924-3873 (hey, don't caU much after 4:30 pm 
EST, okayFL f^icfofUm edition — iMi¥ersity Microf tints, Ann Arbor Mf 43T06. T^es — Sctence for the Bfind, 332 Hock Miff Hd, Bala 
Cynwyd PA 19904^ Entire contents copyright 1976 by 73, fnc. INCLUDE OLD ADDRESS AND ZIP CODE WITH ADDRESS 
CHANGE NOTIFICATION. 



4 



Staff 



EDITOa/PUBLISHEfl 
Wsyne Green W2NSD/1 

GENERAL MANAGER 
Biff MaliDf*e¥ 

MAMAGIMG EDITOR 
Jolvt Cl Burnett 

ASSISTANT EDITOR 

A5SOGIArE EDITORS 
Atei Banfkks WB4RVH 
Fred R. Golds tcm WAIWDS 

PRODUCTION MANAGER 
Lynn Panciarfl-Frawr 

ART DEPARTMENT 

Nartcy E-Stlfl 
Peri Mflhonev 
MccJiael Murphy 
Boil Sawyer 

PRIPtfTER 
PHOTOGRAPHY 

Bin H^ytkilpH 

TYPESETTIMG 
B^iTiura i. Lmi 

ADVERTISING 

e>ii Edwards WB6eE!>/1 

Nsncv Cluff 

COMPTROLiER 

Knud E. M. Kdlor KV4GGn 

CiHCULATlON 

Barbara Block 
SySiSn Chandlitr 
pj^rtces Dilion 
Dorothy Gibson 
FkfiTBfiqe GctlEfman 
Peerf Lahey 
Mirgs McCarthy 
iudy Watefnwi 

MAHKETlNa 

Swrty Srnylht 

INVEMTORV CONTROL 
Kim Johansson 
M^rshafl Ravmond 

PLANT MAINTENANCE 
BtU Barry 

ASSOCIATES 

Robert Baln^rWAt sex 
E, H, Barnelt WB01IX 
SchlBv Cox WaSLHO 
TofTi DiBi^se WB8KZD 
Terry Fox WB^JFt 
W. San£|er Green 
Dflvc Ingram K4TVi/J 
Joe Kasser GSZCZ 
BiirPaflCTnakWABlTF 
Jo^nSehute W?E|Y/K3E2 
Wal^ Scott KSQIZ 
Pets A. SiMk K20AW 
BJ»I Turner WAiABI 

DRAFTING 

Bill Monilo 

LynnMaED 

T. M. Graham irWBFKW 




EDITORIAL BY WAYNE GREEN 



MINING ADVERTISERS 

Many readers have been writing in 
to a&k about specific manufacturers 
wtiose ads have noE been running in 
73^ Since 73 has more ads than any 
othef ham fnagazine . , . and since the 
73 policy is to refuse ads to unreliable 
firms . . . firms which are advertising 
in other ham magazines even thougli 
the pubtishers know ihey are un- 
reliable . . . readers ask^ to make sure, 
whether such and such a firm has been 
refused ads in 73, 

Several readers have asked about 
Eimac recently. El mac advertises in 
the other three ham magazines, but 
not in 73. As far as we know the 
reason for this is that Eimac is iryirig 
to put pressure on 73 to run non- 
controversial editorials. No one in the 
iTKJustry is 9oirig to force 73 to run or 
rtot to run anything, includirig 
editorials, and we at 7J think that thts 
attempt to use economic poM^r to 
influence ttie press tsa serkous matter. 
Bead ifie editorials in the other ham 
magazines and decide for yourself 
how wccessFul Eimac has been . « . 
not a controversy in a carload. 

We at 73 think that thought- 
provoking controversy is healthy for 
amateur radio , . . and we know with a 
certainty that it Es healthy for 73. 73 
is published for the readers and will 
continue lo be responsive to the 
readers, not manufecturers who try to 
buy wliat they think should be in the 
rtiagazines. Ads should be run for the 
purpose of selling products, not for 
forcing the ntanui^iturer's vtews on 
tfie editor, 

Eimac is big enough and indepen- 
dent enough of tfie ham market so 
they can do very well with or without 
tram mapziiw advertising. This puts 
them In a good position to throw 
weight around . . . weight which few 
magazine publishers can afford to 
ignore. 

About the only difference to the 
average 73 reader is that each issue of 
the magazine is just a few pages 
thinner * , , perfiaps there is one less 
article as a result of the Eimac boy- 
cotL 

Another missing advertiser, of late, 
has been EBC We at 73 felt that the 
EBC rig did not meet the published 
specs zf)d field up furtfier ads untti the 
situation was cleared up. Becent 
reports are that EQC had cleared up 
the problems with the rig so as soon as 
this can be verified by a test of a new 



rig with all the latest mods, EBC may 
be back m 73 again. 

Missing ads like that are expensive 
both for 73 and for the advertiser, so 
ads are not held up frivolously. 

MORE HAMFESTS? 

If local hamfests were better pro- 
moted to bring in CBers arid other 
prospective hams instead of just being 
geared for the entertainment of those 
already licensed, vve might be ahte to 
bootstrap more chaps into our 
interesting hobby. 

Hamfests can be run for a profit^ 
you know. Those interested in finding 
out details on how to make big money 
out of hamfests should get in touch 



with Leonard Norman , . , an ex-ham 
(the FCC took away his ticket) . .. 
who has been running 'em for years in 
Las Vegas. Write to him at his conven- 
tion headquarters in Boulder City, 
Nevada or, if tf^re is any problem, get 
his Boulder City office address from 
HBm Badm Magsiine in GreenvHie NH 
, , , they are very close to Norman. 

Commerciahsm c^n go too far, of 
course, so you have to be careful 
about this. If you charge for manufac- 
turer booth space, for admission, for 
technical talks, dinners, cocktail 
parties, and everything, you may find 
interest dropping. You may be able to 
get away wEth having a manufacturer 
pay for a cocktail party . . . and then 
Cofrtinued on page 100 



HINT OF THINGS TO COME? 

h this a rmw CB magaifne? Thank$ to Marc Leaimy WA3AJR for spotting 
ihls ''new" Q$Tcoi^r. 




* Devoted Exclusively to 

CITIZEN RADIO 

FublisHcd by the 

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ROCKV MOUNTAIN HiGHS 

Asperi was a blast — all thiat we 
expected and then some! We all 
regretted leaving there, that's for sure. 
I skied solidly for six days, starting 
Sunday, January 11, on the four 
11, 000' foot mountains — Aspen, 
Aspen Highlands, Buttermilk and 
Snowmass - and found them all 
superb. Aspen village Is located at the 
foot of Aspsn Mountain and Aspen 
Highlands, and Snowmass was about 
12 miles away» 

Chuck WA1KPS. Wayne W2NS0, 
and Pete WegPLW from Illinois took 
lessons on Buttermilk most of the 
week and I skied with Eric WA1H0N 
from Lincoln, Mass. We did our 
damndest to ski everywhere, but were 
lucky just to hit every lift on the 
mountain for one ride during tlie day. 
That's how many lifts there were and 
how big the mountains were! Most of 
the trails were very wide, sweeping 
down the mountainsides. Sugar loaf in 
Maine has, in my opmion, the only 
trails in the Northeast at all com- 
parable and it's less than half the size 
of; say, Snowmass, The weather was 
clear almost every day we were there, 
with the exception of Monday when 
we had snow flurries. The scenery was 
simply majestic with snowcovered 
mountains and valleys visible in every 
direction. The temperature during the 
day ran from 15 or 20 degrees to 
about SO to 40 degrees by the end of 
the week. Because of the altitudes 



hat you 

(Aspen village is 8000 feet — almost 
2000 feet higher than New England's 
Mount Washington), we'd get winded 
easily; I came up puffing just from 
bending down to buckle my boots. 

We all carried 2 meter FM wa Ikies 
and had fun chatting together on "52 
direct" between mountains whiie 
riding up on the chair lifts. No re- 
peaters yet in Aspen — wait until next 
time! Chuck brought along an Atias 
SSB transceiver and Dentron tuner 
and we had a batch of 75m QSOs 
using an end- fed 'long wire" hung on 
the hotel balcony one dark night. 

Our hotel was very nice as expected 
— very convenient, located between 
the two chair lifts at the foot of 
Aspen Mountain, about a block from 
the nearest lift and a block from the 
bus stop from where the free bus 
shuttles ran to all the other moun- 
tains. After skiing each day, we 
jumped into the hotel's heated pool 
for awhile, Boy, that hot water was 
great for the aching muscles after 6-7 
hours of skiing! Fun to float on your 
[3ack and look up at the stars or 
snowflakes, whatever. Then, into the 
sauna to sweat for a btt in its 230 
degree temperature. We all got 
together for supper every night, which 
was a "peak" experience of the day, 
since, although the town has a popula- 
tion of 7000 to 8000, it has 80 
restaurants and nightclubs and we 
went to a different gourmet restaurant 
each night. Supper would last a couple 
of hours, then maybe we'd look in on 
a nightspot briefly, and off to bed. 




;:^ t 




The restaurant prices were a bit high 
— a was everything else in town — 
usually supper cost around 15 bucks 
apiece. But the food and service were 
superb. 

We did encounter several un- 
pleasant situations, unfortunately. We 
had a beautiful flight out to Denver 
from Boston on Saturday, January 
10th. Chuck, Eric and \ met Wayne 
W2NSD, fresh in from the SAROC 
hamfest, at the Denver airport. That's 
where our troubles began. Seems that 
the little airline which was to ffy us 
the 200 miles out to Aspen had sold 
at least two tickets for every available 
seat. Things were totally screwed up 
when we arrived with a lot of people 
standing around getting unhappier by 
the moment and the airline people 
acting unpleasant about the whole 
thing. Wayne finally managed to get 
on a plane and leave for Aspen, but 
not the rest of us. After we'd been 
there about 4 hours, we said the hell 
with it, cancelled our tickets, had a 
heckuva time reclaiming our bags and 
skiSp rented a car and set out about 7 
pm to drive to Aspen, in spite of 
warnings about icy roads and snow- 
blocked mountain passes. Fortun- 
ately, the weather was f'me, and with 
good moonlight, the visibility was 
excellent. Immediately west of 
Denver, w/hich is 5000 feet, you climb 
into the mountains and we drove over 
a couple of 11, 000- foot passes, a 
fantastic drive. Passed the Love land 
ski area, the top of which seems to be 
above timberline, then through Vail 
which is a mass of condominiums 
tucked in a narrow, deep valley, and 
some other big ski areas 1 don't 

remember the names of. Finally, about 
midnight, we left the main highway 
west, and drove the last 40 miles or so 
south to Aspen, arriving about 1 am. 
We finally found the hotel after plow- 
ing through masses of party-goers 
{that's Aspen every night!) and of f to 
bed. Up early and off to Buttermilk 
for a super first day of skiing in 
foot -deep powder and baimy weather. 
When we returned to the hotels Chuck 
and Wayne's room had been robbed: 
tape recorder, still and movie cameras, 
airline tickets, and a 2m walkie — in 
alt about $2000 worth. Three days 
later, Pete WB9FLW from Illinois, 
who had joined our group, had his 
room robbed. There were several 
other thefts from our hotel during th« 
week. Chuck caught a bad cold and 
was unable to ski for the last two 
days. On a few occasions, we were 



overcharged for meals, hut our sharp 
eyes caught the errors. 

It was a great vacation and my 
skiing here in New England can now 
be described as only second-best. You 
can't believe how much fun it is to 
run those big beautiful trails out there 
— even the moguls are bigger — can 
you visualize Cannon Mountain's 
Zoomer or Polly's Folly trails half to 
three-quarters of a mile long or even 
steeper? Or skiing a trail even longer 
without seeing one mogul? Or being 
scared stiff while riding a chair lift up 
an HOOD-foot high narrow ridge — 
just wide enough for chair hft and ski 
trail underneath and looking down 
sheer cliffs on either side? I was in 
terror on that one, located at the top 
of Aspen Highlands. Rode it a second 
time to see if I was stOI scared — I 
was ... Or the beauty of the snow 
plume blowing off the 14,000 footer 
up the valley between Buttermilk and 
the Highlands. Or the memory of 
stopping high up on Aspen (Ajax) 
Mountain !ate in the afternoon and 
looking down at the village a couple 
of thousand feet below. Or the sheer 
fun of running the open snow fields 
near the summit of Snowmass, called 
the '"Big Burn," due to a fire which 
cleared most of the trees from the 
area years ago. Still an occasional tree 
there to dodge in the half-mile wide 
ski "trait." One can get spoiled fast 
with this kind of a mountain. 

So, inevitably, it all came to an end* 
On the 17th, we caught the shuttle 
bus to the airport near the foot of 
Buttermilk, packed Into the little 
twin-engined Otter aircraft — big 
enough for 19 passengers, and climbed 
out over the Aspen vaUey en route to 
Denver, about an hour away. No cabin 
pressurizatlon — my fingers turned 
blue, Wayne appeared to be slumped 
over up forward. Scenery below was 
superb. Then, big DC-10 airbus to 
Boston — 2 seats wide on either side 
plus 4 seats in the middle. Landed 

a little after 6 local time and found it 
bitter cold and windy in Boston. 
Home about 8, vacation over, I'd like 
to give some credit where It is due — 
first to Wayne and Chuck for the 
whole idea last summer, to Rocky 
Mountain Airw<jys who provided us 
the inspiration to drive from Denver 
to Aspen (I wonder whatever hap- 
pened to the 47 anxious folks ahead 
of us in the Rocky Mountain queue at 
Denver), to the Continental Inn at 
Aspen where the accommodations 
were excelJent, but had unsolicited 
room serivce (the burglars), and to 
amateur radio itself which got me 
going on the best vacation imaginable 
for this ham skier. 

Sandy Cole WtPVF/1 
Concord MA 



HI YOURSELF 

Just received your new 73 format. I 
don't like it. Looks like m id-winter 
Sears sale catalog. Hi. 

JackKunshK7YjMV 
Stanford MT 



6 



[ 



WHAT SERVICE! 



I would like to tell you how pjeased 
I am wrth one of your advertisers, I 
mailed two separate orders at 
different times to James Electronics. 
Both orders were mailed on Sunday 
and received back in my mail box the 
following Saturday. What service f 
Also I received 100% of what was 
ordered. No back orders, no substitu- 
tions, and no oversights. You can't 
Mieve how easy thts makes building a 
project. Others are still waiting to 
receive their B/Os or missent parts. 

Harry R. Clement 
Des Moines I A 

I recently placed orders with three 
of the advertisers in the pages of 73: 
S. D. Sabs, James Electronics, and 
A P Products, Inc. 

All three of the orders were re 
ceived complete, exactly as ordered, 
within 10 days of my mailing of the 
orders!!! This is fantastic! II S. D. 
Sales even included a free package of 
LEDs, which is unheard of when 
dealing with the large suppliers, 

I'm sure I am not alone in saying 
THANK YOU to you and the adver- 
t[sirig staff of 73 for making it possi- 
ble for these relatively small com- 
panies to become known to your 
readers. I think that it is unfortunate 
for amateur radio that the January 
1976 issue of QST contained only one 
advertisement from a small parts 
supplier which, incidentally, was not 
one of the three listed above. 

Please continue with your work at 
73 in the same vein as you have been. 
We may not always agree with your 
viewpoint, but at least you do make 
your readers aware that there occa- 
sionally c&f} be iustifiable, sensible and 
rational alternatives to the ARRL 
posrtion on various matters. Thanks 
for the originality of 73\ 

Louis A. Hodges W9LM I 
Chester I L 

Thanks, Louis — f do like ro hear 
about good experiences with adver- 
tisers. / also wartt to hear immedmtely 
about any bad expensnces with our or 
Qther magazine advertisers, i have 
been known to mse heif over things 
iike that 73 ioses a lot of money 
ei^ry month by refusing to accept ads 
from firms running ads in QST, HR 
and CO . . . / need to know who ti^ 
good guys are and who the bad guys 
are . . . and i want to kno w when they 
change their spots. Re my editonais 
... / get a big laugh oat of a few 
manufBCtarers who won^t advertise in 
73 t^ecause they think this wili force 
me to run ^^Itype editor iafs * * . 
thafs dumb, f write my stuff to get the 
juices running and whether t believe 
what / write or not is irreievant. / 
want readers to think and have some 
fun. Oh, a few get up tight ... but 
you know, oddly enough^ / get vir- 
tue I ty no letters to the editor which f 
could use instead of my editorials to 
get readers thinking . . . pity, for I'd 
rather be out skiing then writing ^ 



Without controversial ideas, 73 would 
be just like the other ham magazines 
. . . end you wouldn't want that — 
Wayne, 



KEEPING PACE 

KSYYP's request for heart pacer 
informatiijn reminded me that others 
having or contemplatirtg a pacer in- 
stallation might benefit from a 
cassette tape made by VE7QQ, 
another pacer recipient. 

Sadly, Ken VE7QQ died from other 
(^uses. However, I will make a copy 
of his interesting recording, at cost, 
for those interested. 

Yes, I contacted K8YYP. 

Gene Brizendine V\f4ATE 
Huntsville AL 



EXCEPTIONAL OAKLAND 

In light of recent editorial com- 
ments about repeater operations, we 
feel that certain points should be 
brought to light. In our area, we have 
a repeater [of which we are both 
control ops} which does provide a 
source of intelligent discussion and 
which does provide first rate emer- 
gency service. We are speaking of 
WR2ABN 00/70) in Oakland, N.J. 

We have both had the privilege to 
monitor and to participate In serious 
discussions of music (both classical 
and jazz), astronomy, astrology, 
religion and philosophy on this 
repeater in the evening hours, and 
have found these discussions most 
stimulating. 

Likewise, the Oakland 10/70 
machine regularly handles more emer- 
gency traffic in a week than any of 
the repeaters listed in that other maga- 
zine do in a month, a fact which we 
Intend to publicize further. In addi- 
tion, in every instance of bad driving 
conditions in the metro North Jersey/ 
New York City area which has 
occurred in the past year, WR2ABN 
has been used almost continualjy 
throughout the period as a clearmg- 
house for road and weatlier informa- 
tion, with formal net control and 
monitoring of the National Weather 
Service reports and local police chan- 
nels to provide greater assistance. 
Travelers in and through our area 
know that, if they should need assis- 
tance or encounter an emergency dur- 
ing the normal operating hours of the 
repeater, they need only put out a call 
for help and someone will come right 
back to them. 

In contrast, local Citizens Band is 
almost impossible as far as trans- 
mitting a readable menage through 
the din is concerned. The total dis- 
courtesy and lack of concern for any 
sort of operating standards is the rule 
here on CB. In much monitoring, we 
and others have yet to hear an emer- 
gency report on CB In this area, even 
on Channel 9, because that too is 
usually clogged with multiple QSOs all 
interfering with one another. 

In short, we do not really wish to 



disagree with your premises entirely, 
although we have both encountered 
other machines elsewhere which are 
also most helpful, but rather to point 
out that. In our area, WR2ABN is an 
exception to the sentiments expressed 
in recent issues. 

Page E. Taylor K2QAR 

Butler m 

Russell J. Edmunds WB2BJH 

Kinnelon NJ 



QUICK AND CHEAP 

Suggestions from a pre Novice — 
Include projects on a regular basis that 

can be constructed cheaply and would 
help a Novice to get on the air. 
Examples: T-F^ switches, CW trans- 
mitters and receivers, quick and cheap 
antennas, etc. 

If Vie are to attract new people to 
amateur radio we need attractive pro- 
jects that can be built quickly, from 
readily available parts, and give the 
builder an immediate sense of partici- 
pation in radio. Construction projects 
for Novices are all too often built and 
designed by amateurs with years of 
^'junk box" materials and experience 
at hand. Novices, on the other hand, 
have no used parts, no familiar sources 
of supply, and little or no schematic 
and construction experience. 

The 5 band transmitter on pg, 125 
of the Nov/Dec issue Is a typical 
example. This transmitter is just what 
Tm looking for. However, the article 
does not include a complete parts list, 
has no wiring diagram that shows 
component placement, and makes no 
attempt to teach a Novice. The 
project could have included construc- 
tion details, theory, suggestions for 
coupling with a receiver/antenna {T-H 
switch )r and a single source that sold 
all parts. 

The scope project on pg. 74 is 
much more complete, as it includes 
many of the details mentioned for a 
Novice project. Yet this project is 
written for far more advanced hams. 
Quick and cheap projects seem to get 
short and sweet space in magazines 
these days, yet If a beginner can't get 
started, he will move on to another 
field of interest — one that will gratify 
his needs and interest. 

William Cook 
Alpena Ml 



ROCKING HAM 



] 



I want to tell you how much that 
13+ wpm code tape has really helped 
me. Believe me, I've only spent a total 
of less than 7 hours, and my speed is 
up to about 1 5 wpml 

I am 20 years old (soon to be 21 L I 
took my Novice test in Nov. 1974 and 
got the license in Jan, 1975. Then 3 
months later I was out of work for 3!4 
weeks because my place of work had 
to close for remodeling. So 1 "boned 
up" on the theory (even though 1 
knew some radio theory) and the 
code. Then in April, 1975 (note the 3 
months later! ), I took the General and 



Advanced on the same day and 
passed! I also ujed your tape at school 
in spite of the other kids giving me 
that weird look. 

I also plan to go for my Extra class 
soon, t also agree that if you war>t 
that ham ticket, earn it! Qon't sit 
around lazily and hope someone else 
will give it to youf 

I now work 2 meters as wall as HP, 
and would you know? These guys on 
2 meters are beautiful and 1 love 
tbeml I've received a lot of help from 
them too, which I dearly appreciate? 

I'm also planning to get up a rock 
group and call it '"Larry WA4MJQ, 
And His Ancient of Days." Who 
knows? This may indirectly expose 
amateur radio to the public 

After reading some articles in 75, I 
also want to note that Tve also had 
trouble with Trigger Electronics. How- 
ever, I did get my money back through 
the intervention of the Postal Inspec- 
tion Service, 

I really like your magazine! 

Larry S. Lawhorn WA4MJQ 
Ric^hmond VA 

COMPUTERE(A)SE? 

Keep the microcomputer articles 
coming . . . 

Robert Brubaker K3UPK 
Lebanon PA 

Thank you for stimulating our 
interest in computers. 

What we need now is articles which 
tell us for what purpose we may use a 
computer. 

What will a computer do for us in 
the home, the workshop, and the ham 
shack? 

Tell us. It will help us to know the 
applications, and that would in turn 
be good for the industry. 

Harry O, Minshew W6Z0W 

HemetCA 

Right I Well, I can think of a lot of 
things I want to do with a computer, 
such as get e list of the times and 
antenna bearings for accessing Oscar 7 
. . . playing Star Trek, Twenty-One, 
Lunar Landing and many otfwr games 
. , . keeping an index and fist of all tfte 
recipes I like , . .an index to ail of the 
hem articles of possible interest to me 
such as RTTY, SSTV, uP, FMI . . . an 
index to my record and tape coHec- 
tions . . . a list of ell the repeaters in 
tfw world . . . a fist of all the DX 
stations rve contacted and the details 
about them, QSLs > . . my checking 
account . . . generation of SSTV 
pictures end art . . . generation of art 
on my color TV set , . . RTTY genera- 
tion and contacts over the air using 
Baudot, ASCII or Morse Code . . . 
accessing other computers via Oscar 7 
. . . mailing list for some clubs / 
belong to , . , editing letters and 
articles which s3id computer then can 
print out , , , key word sorting RTTY 
short wave news broadcasts for any- 
thing concerning amateur radio . . . 
checking for any calls via any re- 
peaters within range automatically . , . 



tt^f'rigs like that With two or three 
termmsis most computGrs can do 
several tasks at once . . . okay? 

— Wayne. 

I will not forgive you ^or bringing a 
new Interest into my life, just when I 
had decided that I had more than 
ervDugh projects to keep me busy. A 
friend of mine, Dave K5WMV/7, has 
an Altalr &300 with 16K memorv. 
CRT terminal and TTY I/O, Friday he 
brought home from Albuquerque one 
of their floppy disk units. Since I 
don't want to get in that deep and his 
unit is idle a good deal of the time, we 
have started a ham rad to-computer 
project. We live 25 mEles apart and he 
IS going to send me the widao output 
from hts I/O port on 439.25 IVlHz and 
I am going to access the machine with 
an ASCII keyboard modulating a 147 
MHz FM transmitter. At least that's 
the plan. We've applied to the FCC to 
use ASCII on two meters. Enough for 
now — I'll get Dave to write it up 
when we are up and running- 

Rod Hailen WA7NEV 
Tombstone AZ 

Sure like the new format, but am 
wondering about all the highly tech- 
nical computer and digital articles you 
feature, Tm an Extra and schooled as 
^n E. E., but this stuff is so far beyond 
me - only thing I understand is the 
title. Tm certainly for progress, but it 
seems marty of these articles are way 
beyond the normal reader you may 
have, i take all tour ham pubs — and 
like yours the best — but tionestly it's 
leaving a good part of us in a cEoud of 
dust. Respectfully submitted, 

Lon C. Brickley W4AFS 
Pom pa no Beach FL 

\i you live in the metropolitan New 
Orleans area and are interested in 
computers, you are invited to join our 
group. Whether your interest is hard- 
ware, software, applications, or just 
general interest, we welcome your 
input. For further detaiils please write 
or call me, 

Emile Alline, Jr, WA5WUJ 

1119 Pennsylvania Ave, 

Slidell LA 70458 

504-641 2360 

P.S. Keep up the good work — espe- 
cially in translating '*computerese." 



ENTERPRISE 

Just finished building the Starfleet 
Communicator (February, 1976). 
Nice toy; the girls love it! However, I 
did have some trouble getting the 
little unit going, and so olfer the 
following suggestions to those who 
have built, or will build, this device. 

First off, use only a fresh, heavy- 
duty 9 volt battery when checking out 
the unit, Secondly, the voltage on piri 
5 of ICI {7493J should be fairly close 
to B volts. When I first tried the unit, 
the voltage on this pin was less than 
4.5 volts, and the communicator 



would not function. The problem 
could have been due simply to the 
characteristics of the various devices I 
used. The LEDs were from James 
Electronics (Model XC526), while the 
UJT was one contained in a package 
of 4 which was purchased at Radio 
Shack (Part Number 276-1 11|. 
Regardless, I towered the 100 Ohm 
resistor in the 5 volt supply line to 
about 50 Ohms so as to obtain the 
proper operating voltage. 

At this point, it was necessary to 
lower the 82 Ohm resistor in the 
gating line (pin 11 of ICl) to 39 
Ohms, an-d to bypass pin 14 of ICl 
with 0.3 uF (for noise suppression) 
before the unit would function. 

Some other hints ... I built my 
unit in the case of an old transistor 
radio. This provided the case, a 
speaker, and a battery compartment 
all in one step. Further, not wanting 
to bother with the flip-up top, I 
simply mounted an SPST switch on 
the spde of the case which Is used to 
activate the communicator* Finally, I 
used ElectroCraft Model 35-414 
push button switches (miniature, 
momentary switches)- for S2 and S3. 

As I said, the unit is working and 
the girls love it (ages 6 and 7). 
Further, I learned quite a bit in the 
process of building it. Hopefully, with 
the above info, others will have an 
easier time getting their communica- 
tors goj ng. 

Ted Cohen W4UMF 
Alexandria V A 

P.S. James Electronics is fantastic! 11 
Ordered some parts by mail on Satur- 
day, and had them by noon, the 
following Wednesday] 



YL 73 73! 

Recently Jim Ricks W9T0, inven- 
tor of the world-famous keyer, sent 
his young lady to pick up his auto 
tags. Completely by chance, his new 
plates re^: YL73 73 ! 

Gene Brizendlne W4ATE 
Huntsville At 




BAD APPEARAIMCE 

I recently learned a valuable lesson 
about automobile security. While 
parked \n a hotel lot in Milwaukee, 
my car was broken into, and my 
broadcast radio, along with a good 
part of the dash, was stolen, This was 
not a tape machine, and an examina- 
tion of nearby cars turned up several 
with better, more easily removable 
units. However, my car did have the 
bottom half of an HF antenna on the 
bumper. The police seemed to think 
that the thief was looking for CB 
units, and being unable to see through 
the frosted windows, broke in, and 
then took what was there. I guess the 
moral is avoid even the appearance of 
a rig in the car. 

Alan P, Biddle WB9SQB 
Madfson Wl 



I really enjoy your magazine. I'm 
planning to get my Novice license 
pretty soon.o o you think you could 
have a few how- to-do -it articles for 
the guy who is not too experienced, T 
hanks. So much for my typing, 

Tom Rosicka 
Springfield OH 

THE GUEST FOR THE HOLY PR 

Please eyebal! the enclosed PR spot 
I landed in my local newspaper. Tm 
proud of it and you should be too, 
because WA4BDW's story in the Jan. 
73 Inspired its beginnings, You know 
this guy had a lot of nerve with his 
Item ^2, "Land a feature story En a 
local newspaper," bit. But since the 
CBers get it done now and then I 
thought what the he3t. So I wrote Bob 
I verso n (author of article enclosed) a 
letter and invited him over to the house 
to see what I had going, I baited the 
invite with things like Oscar, ATV and 
the like, and used the basic premise 
{per FCC R&R) that hams are arour>d 
to provide emergency communica- 
tions and enhance internatJonal good- 
will. Note how that got in the first 
paragraph, 

This story appeared on Sunday, Jan 
1Sth in the Danville Commercial 
News, which Is owned by a big outfit 
called the Gannett News Service. The 
local paper circulates better than 
75,000 with Danville, Illinois the 
hometown of about 41,000 people. 

You might be interested in knowing 
that I took about an hour to prepare 
for the reporter's interview by pain- 
stakingly book mar king articles 
(especially ones with photos} from 73 
and QST to back up everything in the 
story. My presentation took about 25 
minutes, including questions from 
Iverson and the photo. It was topped 
off with a short QSO with WM4BSL in 
Owensboro, Ky. for effect, \ might 
add that my presentation was very 
general and not at all technical, touch- 
ing on a variety of things which I 
thought non-hamming, non technical 
readers might like. Again, the basic 
premise was to make aware the 
existence of us in the event of a large 
scale disaster. Detente is In too, so 
hence the goodwill. 

A local ham whom I've never met 
called to teU me that the story created 
a tot of interest on the 2 meter net 
and congratulations were offered on 
behalf of himself and all the locals. A 
very nice gesture, \ thought, since this 
guy is a General and is into slow scan 
in a big way, which would have been 
nice for the mug shot. 

At my place of full-time work, I 
was treated as somewhat of a man-of- 
the-hour and greeted by a programmer 
on the staff with "Who the hell do 
you know at the paper?" No one. At 
my place of part time work, country 
FM station WIAL the manager was 
very pleased and intended to send the 
owner of the station and the building 



a copy of it. He lives out of town, in 
fact out of the county, This, despite 
the fact that Wl Al is not mentioned in 
the article, f lock there on weekends, 
just in case you ever buzz around 
here, Wayne. 50,000 Watts 99,1 and 
good country music. What more could 
you want??? 

Anyway, that's my effort toward 
PR, and you and WA4eDW should be 
congratulated for the inspiration. But 
most of all, Bob Iverson of the Com- 
mercial News should be honored for 
his excellent writing and comprehen- 
sion. After all, the reporters have to 
write these things and they really 
decide how well it's going to go over. 

You know, I've read many articles 
telling us we need PR, but no'hlng 
about how to PR. Maybe you could 
help by telling us how to prepare 
feature article presentations, or HOW 
to set up booths at local CB jamborees 
or HOW to give demonstrations for 
school science classes. Some of us 
don't know how to organize our time 
or talk or any damn thing, I made my 
presentation without any idea how it 
would turn out. Lucked out I guess. 

Well, so much for all this. Hope you 
enjoyed the clipping and thanks for 
listening. Also like the new mag 
format It's about time. 

Ted Osborn WN9PiQ 
Danville IL 

P,S. Also, tell Mary she did a fine job 
with my Reader Service requests for 
this month. 



INFLATION 



1 



In reference to the January 76 issue 
of 73 M$gaim&. The article "County 
Hunting" by W2SDU quotes the price 
of Directory of Post Offices available 
from Government Printing Office 
under stock No, 3900-00242 at S4.35. 

Have just received the copy I 
ordered and find the correct price is 
now $5.05 — the price quoted now 
being obsolete. 

Earl Stacy K7BD 
Selah WA 



IN ENGLISH. PLEASE 

In reference to your article "Stereo 
— A New Type of CW Filter," in the 
Marcin issue, it doesn't take much 
imagination for RTTYers like myself 
to stick the Mark and Space scope 
monitoring audio outputs of the tele- 
type converter into an inexpensive 
"hi-fi" stereo amplifier and tune for 
equal left and right separation of the 
FSK signal. Using stereo headphones 
gjves you a pretty broad left-to-right 
audio "picture" of the signal so that 
centering the FSK around the cross- 
over point is fast and very accurate. 
Note that QSBing of the Mark and 
Space frequencies does not effect the 
tuning sense you have as you bring the 
signal into proper position. This 
simple method of tuning FSK gives 
you a great sense of security, because 

Continued on psgs 74 



B 



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The IC-22A has caused some pretty big surprises since it first started making waves in 
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last, you're in for a little surprise. 



seuiicoNDucroRS 

TRANSISTORS 

FET 

IC 

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FREQUENCY RANGE 
CHANNELS 

MOOuuvnoN 

VOLTAGE 

SIZE 

WEIGHT 



22 

4 

32 

Phase. F3 

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1 7 kilos 




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INTERMEDIATE FREQUENCIES 

MODULATION ACCEPTANCE 
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AUDIO POWER 



HMOVtetts, L01 Watt 

1 SKHz wTtti 5KH2: deviattm 

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VHRUHF AMATEUR AND MARINE COMMUNICATION EQUIPMENT 



Distributed by: 




ICOM 



ICOM WEST, INC. 

Suite 3 

13256 Northmp Way 
Bellevue, Wash. 98005 
(206) 747^9020 



ICOM EAST, INC. 

Suite 307 

3331 Towerwood Drive 
Dallas, Texas 75234 
(214) 620-2780 



to 



Looking West 



A Dark Horse Will Out 




Ever have a run of Fuck when 
nothing goes right? You know, when 
it seems like the gods have things 
stacked up agt^inst you. That's just the 
way 1976 began. Actually, it began in 
early December when some low 
creature decided that he needed my 
icom IC-2F (serial 5x4893 If you 
happen to run across il^ more than I 
did and went to the trouble of pur- 
loining said radio from under the dash 
of our '63 Cadtllac, I sa^d tfoubie^ 
since it not being my nature to trust 
mounting brackets and such^ I Nad 
driiled three holes through the top 
case cover and mounted the radio 
directly to tti« dash in as inoan- 
sptcuousa spot as t cotifd find. 1 guess 
tbe spot was |usi not tnoonspicuous 
enough and scratch one IC-2F. 

On New Year's Eve I remember 
telling Sharon that '76 would be 
better than "75; it had to be. Was old 
rXF ever wrong! On New Year's Day 
afternoon, the oil pump in our '71 
Torino let go and took the engine 
with It. Oh, the idiot light did come 
on . . . after the car hasJ chugged and 
grinded its way to a stop. My thanks 
to the many amateurs from both 
WR6ABB and WR6ABE that came to 
our aid and got us down to sea level 
from alop IVIuhulland Drive, and a 
special thanks to George WA6MQM 
who is current I V hard at work putting 
ail the pieces together once more. 



This morning, though, was the 
clincher. Though on its last legs, the 
old Cad was still running and I had to 
renew my driver's license, The Depart- 
ment of Motor Vehicles office is 
about a mile from here, so bright and 
early this am, I drove over and 
obtained my renewal. I was going to 
make a stop at one of my parts 
suppliers when t noted some steam 
fn>m under the hood. Well, this car 
has had a water leak since I bought it, 
but it ts at ways wise to check. fieir>g 
almost at my house. I drove there artd 
parked. Lucky I d^d, since it seems 
that the water pump and the radiator 
had giver) up at about ttie same time. 
Have von any idea wtiat it's like to be 
sans wtieels in Los Angeles? You 
t^nnoi even get to the corner unless 
you have a car, and here 1 SJt in our 
Jfvir^ room — the to to score, 2 down, 
D to go! Oh weilf it *75 was bad. so 
far '76 coutd be classified as a 
disastefl 

The Torino going down for repair 
came at the wrong time — Just a w^ek 
prior to SAROC* We had about given 
up hope of getting there when Rick 
WA6VSK offered us a lift across the 
Mojave to the fun city of Las Vegas. 
Three people and all the necessary 
luggage packed tightly into the con- 
fines of Rick's 72 VW bug. Reminds 
me a bit of a trip cross country in '70 
with Lou K2VMR in his VW lovingly 

...... r^:fit»ir|iiiiTmiIS5!fS 

ilufiri ffinnp'^'f^^ 




called BUGSY, but that's another 
story. Anyhow, aside from the sardine 
can sized transportation for which we 
will be eternally grateful, it was a 
most enjoyable trip with yours iruly 
playing pilot. It should be noted that 
this area Is enjoying (and I use that 
term loosely due to the fire hazard 
now present} a very warm and dry 
winter season. In fact as I write this, it 
is Feb* 2, the temperature is almost 80 
degrees and kids are out swimming in 
the apartment house pool. While 
slightly oooJer. the weather across the 
desert and in L^ Vegas was simitar. 
Beaut if uL 

Since 1 described SAROC last year 
in some detail, I will rwt bore you 
again with the same story. Suffice rt 
to say that SAROC is unlike any other 
amateur radio convention in that the 
CFty of Las Vegas rather than the 
convention iEself is the top attracCcon. 
Las Vegas is a world in itself and one 
of my favorite vacation spots. I really 
think that Vegas should adopt the 
motto "Have Fun and Enjoy" since 
thafs what the city is really all about. 
Even the "losers" often smile, 

Our first stop upon arriving at the 
Sahara was of course the registration 
desk where we found out that our 
pre paid reservations for that hotel 
had been transferred to the Thunder- 
bird since the Sahara was fut^ up. I 
was set to "blow a gut" when I 



Biff Pmwmak WAGfTf 
14/25 Titus St =4 
Panoranm City CA 91402 



remembered that the Mt. Wilson 
Repeater A^ociation was to be 
hosting a "Hospitality Suite/' A quick 
call on Rick's HT brought forth the 
melodious tones of Bill Orenstein 
KH6IAF/7. Bill advised me to "cool 
my head" arKJ come ap to room 4022, 
better known as the "Mt Wilson 
Repeater Association Friendship 
Suite." This was the 'Dark Horse" of 
which I spoke in the column header. 
White the theme of most hospitality 
suites at conventions ts one of "pany^ 
party/' this one was different. It was 
kept low key — a plara to get away 
from the festivities and regroup one*s 
htead. You were greeted by the state 
flag of Hawaii as you walked through 
the door, with soft music mostly of 
Hawaiian origin playirtg in the back' 
ground. It was just a tranquil spot in 
the middle of the confusion that is 
any convention. 

The room was made possible 
through the cooperative efforts of the 
MWRA, Worldradio News and Midnite 
Radio. If one must single out 
individuals who were responsible for 
the overwhelming success of this 



Capt. Dick McKay K6VEP OefTJ and Gary Wood WASDTX (right) enioy funch 
with John Johnston K38NS^ head of the fCC's Amstmjf and CitUens Division. 




Wayne and Sherry mit with Lon and Syhfi Albright of SANDRA in SAROC 
FM Hospitality Suite. 



n 




Bitt Onnstein KH6tAF/7 (ieh) &nd John Marin WA21EU show Waym 
WB6ALD/7inMWRA Hosptmhty Suite. 



special kind ai canverction hospitality 
center, th«re are two people that then 
deserve special mention. First, Bill 
Orenstein KH6IAF, this time /7, for 
conceiving the »ciea, doing the lagwork 
and giving l^ just atKHJt all his ume at 
SAROC to play host. HowBver, all Ihis 
wpf k MQuld have beef) for naught ff it 
were not for the fine oooperation 
given the MWRA and Bill by the 
Sahara iiself. This cooperation came 
in the form of Mr. BilJy Snyder, 
Executive Host and Assistant lo the 
Presideni of the Hotel Sahara. Work^ 
Ing together, the MWRA and the 
Sahar<i had one of the nicest "let's get 
away from the conveJition for a 
while" spats to be foynd. Heck^ it was 
th« only such spot aside from our 
room at the hotel. Yes, we finally did 
get one by ^^^ way, though we had to 
wait a white, I guess patience wiM ouL 
Now, as if all the above were not 
encugh, there was more. The MWRA 
is a user support organization for the 
Ml. Wilson based WR6ABE repeater. 
Being oT>e of the busrest repeaters in 
the nation, il w^s conceivable that a 
goodly number of its members %vould 
be attending SAROC. For this r^son, 
it was decided that a ponable repeater 
might just be in order. John Barreiro 
WABHOL made available a modified 
Heathkit HW202 which was hirtf^er 
modified, converted and completed as 
a repeater by Kirk Nemzer WB6EGR, 
It was set yp "split- site" with the 
receiver and its antenna on tf>e top 
floor of the hotel and the transmit site 
on the balcony of the MWRA hospi- 
tality room. How does one go about 
tying the ivro ends together so that a 
system such as this can fur^ction? The 
MWRA etectronics crew made use of 
the "house*' phone system, of course. 
Now the frosting on the cake. It Is 
always Qpod to have an }D of some 
type on a repeater and a special events 
repeatef such as this naturally requires 
a special ID. Again thanks to Bill 
KH6IAF/7, the voice of Mr, Jerry 
Lewis could be heard on 146.40 



stating, *Tool^ yaf This is not 
WR6ABE Los Angeles; this is 
WR6ALD/7 at the Sahara Hotel, Las 
Vegas, iust the other side of the 
Colorado River thing ie. Ha hahhhh,** 
To read it ts not to h^r it, and one 
must have heard ft to have raaHy 
spprectated it. A lot of us did 
Thanks, Jerry. 

This was not the only portible 
system lo sfiow up. Tfie Palisades 
ARC of Culver City was there as usual 
with its portable .01/,B1 system, that 
thanks to Neil McKie WA6KLA, per- 
formed at its high level of efficiency. 
One must remember that PARC was 
in the forefront of supplying iheir 
membership with portable systems of 
this sori for occasions such as this. 
Someone else brought a ,93/. 33 
system. I understand, but that never 
really went into full time operation. 

UHF was well represented, with a 
number of remote owners bringing 
their goodie along for use by their 
people. One system, a full-blown 
remote, came In all the way from f^ew 
Jersey aiong with its owners John 
Marin WA2IEU am* his twother Torn 
WA2IKB, But this year it wm the 
MWRA that really stole the show 
when it came to both hospital ity and 
portable repeaters, and for this 
"Looking West" must give them the 
*'Hat5 Off Salute" this year. They 
deserve tL 

Surprises, you bet your sweet 
btppie. I guess tfiat the biggest one to 
yours truly was the guy who walked 
into the FM Hospitality Suite Friday 
evening. None other than 7J*s very 
own Mr. Green himself. I was just 
standing there talking with someone 
when it was suggested by someone 
else that I turn around. Surprise) More 
like shock. Wayne, why don't you 
warn me when you are going to pull 
these surprise visits!? 

Anyhow, not long thereafter, in 
walks Bill KH6IAF and in short order, 
Wayne finds himself shanghaied up to 
the 40th floor to view the MWRA 




Squeak's *'dfinkt&-tafkfe'* - never saw that opt ran in a Motorofa catalog f 



suite and the WR6ALD/7 repeater. As 
you can see from tfic photo, i get ttie 
filing that our "leader" was some- 
wfiat impressed. Unfortunately, it was 
to be a brief visit thiat we would have 
that evening, but in the time ^ had 
to talk I was ab(e to catch up with 
what has tieen ha|3pening back East. 
Wayne wras the smarter of the two; 
after our set-iogether he went ''73s" 
for the evening. Me. I was up most of 
the night talking with this one and 
that one. How I ever made it to the 
FM forum and the FCC forum the 
ne«t day J will never know. Thank 
heavens that someone developed the 
cassette tape recorder. 

At thrs point I should really get 
into a discussion of what Johnny 
Johnston talked about at the FCC 
forum, and until about 48 hours ago 
that would have been exactly what I 
would have done. However, something 
very important has transpired within 
the last two days tfiat deserves very 
special attention now. Therefore, we 
will continue with our coverage of 
SAROC and the FCC forum held 
there nesct month. Right now tt is 
again "Giving Credit Where Credit is 
Due" time* and it is with a feck of a 
lot of pride that ^'Looking West'* 
salutes the accompfishments of a great 
many Soutfiem California amateurs 
wfio have spent the Lasi lew diays 
working hand in hand with the Guate- 
malan Consul General to Los Angela 
in relief efforts to that earthquake- 
ravaged nation. 

For time refererwe, this portion of 
"tW" fs being written on the morning 
of February 9; it Is exactly a week 
since j began to write this and the 
blue skies and warm temperatures of a 
week ago have since been replaced by 
an unending torrent of rain. Winter -* 
the winter we have watted for has 
finally arrived. It's 1:11 am and about 
an hour ago I finally returned home 
from Los Angeles International Air- 
port where I had spent the last Bqt 10 
hours. As a writer it is strange to find 



yourself a part of your own story* but 
in this case it is wfiat happened. 1 had 
gone to LAX to photograph arut 
report on a rather unique and hi^ly 
successful communication effort and 
within minutes found myself taking 
an active part in wttat vias happening^ 
Problem: How do you get commun- 
ication in and out of a country that 
has had most of its communication 
with the rest of the world severed by 
natural disaster? I guess you know tfie 
ariswef, since the answer Is what we, 
the amateur radio oommunity, are all 
about. Sud^ was the situation In 
regard to Guatemala. Less than a week 
ago, that nation suffered a major 
earthquake that according to the 
latest network newscasts has taken 
15,000 lives and effectively cut Guate- 
mala off from the rest of the world 
save amateur radio> Though a number 
of area amateurs had been providing 
communication to Guatemala for the 
past few days, there had been no 
organized effort set up. The local 
consulate had been swamped with 
requests by local citizens as to the 
whereabouts oi friends and relatives in 
Guatemala and the load was increasing 
as hours wore on. It was obvrous that 
some fully organized effort was 
needed, one that would insure that a 
mas^imum numtier of health and 
welfare requests were handled while at 
tlw same lime taking some of the load 
off the local consulate so that they 
co*iM work on other important relief 
efforts. Stich was the problem thai 
Doug K4SWJ/6 posed to me on the 
telephone soma 48 hours ago, Doug« 
like myself, is a member of the 
Palisades Amateur Radio Club of 
Culver City, and both of us felt that it 
was a definite obligation for PARC to 
lake an active role in this project on a 
large scale basis. Saturday morning, 
February 7th, Doug called PARC 
President Dan Deckert WA6FQC and 
plans were formulated. The local 

Contmued on page f38 



12 



Editor: 

Robert Bsker WA fSCX 
34 White Pine Drive 
Littfeton MA QT460 






^ 





CORRECTION 
The Delta QSO Party will he held 
September 25-27 - not April 2^25, 
as listed in our April issue, 

COMMON MARKET CONTEST 

CW 

Saturday, April 3 

0600 to 2400 GMT 

Phone 

Sunday, April 4 

OeOO to 2400 GMT 
Use appropriate mode on atl ama- 
teur bancb, 80 to 10 meters. Pl^se 
keep the lower 10 kHz of the CW 
bands and the upper 25 kHz of phone 
bands free according to lARU recom- 
mendations. Entry classes consisi af^ 
smgle operator — all band, low band 
(80 and 40), high band (20, 15 and 
10}; multi'Operator — single trans- 
mitter, all band only. 
EXCHANGE: 

RS(T) and QSO number starting from 
001. 

SCORfNG: 

Common Market stations score 1 
point for QSOs wfth other Common 
Market stations and 6 points for QSOs 
with othefs; multiply total QSO 
points by the number of DXCC 
countries on each band. Non-Common 
Market stations score S points for 
each Common Market OSO and 1 
point fpr any or her QSOs; muUiply 
total QSO points by the number of 
Common Market countrtes worked on 
each band* 
AWAHDS: 

Certificates to the highest scoring 
station in each country, in each entry 
«?]ass, on each mode. Trophfes 
awarded to the highest scoring single 
operator in the Common Market on 
each mode and to the highest scoring 
single operator outside of the Ckim- 
mofi Market on each mode. 
LOGS: 

AJI entries must be matEed no later 
than April 30th to: Jacky Luyten, 
Ave, Man 134'bl, 1040 Brussels, 
BELGIUM. P^ase use the common 
ioQ form style and do not forget a 
summary sheet. 

Common Market Countries: Belgium^ 
Denmark, France, W. Germany^ Great 
BritBin, frefand, Itafy, LuK^mburg, 
Netherlands. 

TRIPLE LETTER QSO PARTY 

Starts: 1700 GMT Saturday^ 

April 24 

Ends; 2000 GMT Suiiday, 

April 25 

The contest is sponsored by the 

IMiversity of Missouri- Rolla ARC« 

W®EEE and is open to all amateurs. 

Any corrtaci between an^ateurs is valid 

on any band 160 to 2 meters, using 

any mode^ No repeater QSOs or 

cross-mode contacts wilt be allowed. 

Each station fnay be worked once per 



band per mode. 

FREQUENC/ES: 

3950, 7215, 14290, 21375, 2S600. 

CW — 45 kHz up from band edge. 

EXCHANGE: 

RS{T) and consecutive QSO number. 

SCOR/NG: 

Each QSO counts for one point, with 

one extra point added for each 

repeated letter in the suffix of the 

station worked call. An extra point is 

aEso added for 2 letter suffix calls. 

(Ex amplest WB4GQP = 1 pt, 

WA7UMU ^ 2 pts, W0EEE = 3 pis. 

W0GS = 2 pISh) Total ^cx^e h the total 

OSO points limes the number of 

states, countries and provinces on 

each barKl, times the total number of 

triple letter stations on each band. 

Example scoring: 500 QSO pts x 67 

(states, countries and provinces) x 24 

triple letter stations - SI 4,000 fits 

totaL 

EM TRIES: 

Send logs along with the usual data 

and declaration before May 20th to: 

Ward Silver WSaGOP, 590 Fieldstone, 

8aNwinM0 63Dl1. 

GEORGIA OSO PARTY 
Starts: 2000 GMT. Saturday. 

May B 

Ends: 0200 GMT, Monday 

May ID 

The 15th annual Georgia QSO 

Party is sponsored by the Columbus 

Amateur Radio Club. There are no 

t^me or power restrictions and con 

tacts may be made once on phone and 

once on CW on each band with each 

station. 

FREQUFNCfES: 

CW - 1810, 3590, 7060, 14060, 
21060, 28060. SSB - 3900, 3975, 
7245, 14290, 21360, 28600, Novices 
- 3718, 7125. 21110, 28110. Try 
160m at 0300 GMT, try 10m on the 
hour, and ISm on the half fiour 
during dayligbt hours, 
EXCHANGE: 

QSO Number, RS(T). and QTH - 
county for GA stations; state, 
province, or country for others. GA to 
GA contacts are permitted, 
SCORfNG: 

Each completed QSO counts 2 points. 
GA stations multiply total QSO points 
by number of different states and 
Ca natulan provinces worked, DX 
stations may be worked by GA 
stations for QSO points only, they do 
not count as multipliers. Outof-state 
stations witi use the number of GA 
counties 4 max. 1S9) worked tor their 
mul^tipher. 
AWARDS: 

Certificates to the highest scoring 
statiofi in each state, province, 
country, and GA coynty. Also to the 
highest scoring GA and non-GA 
Novice, Second and third pJace awards 
will be made in sections where addi- 



tional recognition warrants. A plaque 
wiM be presented to the single oper- 
ator and mu It i -operator GA stations 
sybmitting the highest score in each 
categorVn Plaques wUI also he awarded 
to the highest scoring out of state 
entry and to the highest scoring GA 
portable and mobile stations operating 
outside their home county. 
LOGS & ENTRIES: 
Your logs should show: date and time 
in GMT, station worked, exchange 
s^n and received, band used, typ^ 
emission, and multipliers claimed. 
Check lists wilt be appreciated. 
Include a signed declaration that all 
contest rules and operating regulations 
were observed and mail your entry to 
CARC, c/o John T. Laney K4BAI, 
Post Office Box 421, Columbus GA 
31902. Entries should be postmarked 
no later than June 7, 1976. Please 
include a large SASE for a copy of the 
results. 

VERMONT QSO PARTY 
Starts; 2100 GMT Saturday, 

May 8 

EfKls: 0100 GMT Monday^ 

May 10 

The 1976 Vermoni QSO Pfflty is 

sponsored by the Central VennofTt 

Amateur Radio Club in Montpelier 

VT. The same station may be worked 



once on eadi band and mode. Mobile 
stations may be worked in each new 
county (consider each new county 
they enter as a new station). 
FREQUENCiES: 

Try CW on odd hours and phone on 
even hours (GMT). 3560, 7060, 
14060, 21060, 2S160, 50260, 
1 44^144.5, 3909, 7266, 14290, 
21375, 28600, 50360. 145,8, 3932. 
7290. 14325. 
EXCHANGE: 

QSO number, RS(T), and county for 
VT stations, or ARRL section for 
oihers. 
SCORING: 

VT stations score one point per oon- 
tact and multiply by the number of 
ARRL sections and countries worked. 
All others score 3 points per VT 
station worked and multiply total by 
the number of VT counties worked on 
each l>and. Maximum of 14 counties 
per band. 
AWARDS: 

Trophies wiil be awarded to the 
highest scoring station outside of VT 
and to the highest scoring single oper- 
ator station in VT. In addition, certifi- 
cates Wit I be awarded to the hi^est 
scoring statkin %n each ARRL section 
and courrtry with a minimum of 3 
different QSOs. Certifiotes also will 
90 to the 2nd, 3rd and 4th highest 







Apr 24 ' 25 
May 1 '2* 
May 1 ' 2* 
May 8 - 10 
May 8 - 10* 
Mays- 10 
May 14- 16 
May 15 
May IS' 17 
May 22 
May 22 23 
Jtfne 4 - 7 
June 12 13 
June 12 • 13 
June 12 ^ 14 
June 26 27 
July 3 ' 4 
July 3 
July 17 ' 19 
July 24 25 
Aug 1 4 1 S 
Sept 4 ' 5 
Sept 11 12 
Oct 8 ■ 10 
Oct 9 - 10 
Oct 16 ■ 17 
Oct 16 18 
Oct 30 - 31 



Triple Letter OSO Party 

MASS Bicentennial QSO Party 

Helvetia 22 Co*itest (H22) 

Georgia QSO Party 

BARC Contest - CW 

Vermont OSO Party 

YL International SSBers QSO Party 

World TeJeoo mm uni cations Day Contest 

Michigan QSO Party 

World Telecommunications Day Contest 

Wisconsin State QSO Party 

lARS/CHC/FHC/HTH QSO Party 

ARRL VHF QSO Party 

RSGB National Field Day 

West Virginia QSO Party 

ARRL Field Day 

QRP - Summer — Contest 

ARRL Straight Key Night 

CW County Hunters Contest 

ARRL Bicentennial Celebration 

European DX Contest - CW 

ARRL VHF QSO Party 

European OX Contest — Phone 

CD Party - Phone 

RSGB 21/28 MH2 Contest - Phone 

RSGB 7 MHz Contest - CW 

CD Party - CW 

CO Worldwide DX Contest — Phone 



Phone 
CW 



« — 



described in last issue 



13 



scoring stations In VT. A special 
certificaie will be awarded multi- 
operator and mobile stations oper- 
ating in VT. QSO Party contacts can 
be credited toward the Worked 



Vermont {W-VT} Award issued to 

stations working 13 out of VT's 14 

counties. 

LOGS: 

In order to be eligible for awards, logs 







RESULTS OF THE 1975 CW COUNTY HUftlTERS CONTEST 
High score - fixed WB40GW 433,048 points Inew rerardl 

High score - portable WA0KXJ/6 220,869 

High score - nrobile WA5KQD/m 438,658 (new reranj) 

Composite mobile score IC0DEQ 292,356 

There were a totsi of 301 counties activated by portable/rrwsbile sta lions 
during the contest, while tbe total numt>ef of coumiies worked by earnest 
stations was 613. The highest number of differerit counties worked tiy any 
sif^le entry was 407 counties (W640GWi, The winners in each state and 
category are as follows: 



STATE 

CONN 

ME 

fAASS 
VT 
NJ 

NY 

MD/DC 

PA 

FLA 

GA 
KY 
NC 

SC 
TENN 

VA 

MISS 

TEX 

CAL 



IDAHO 

MONT 

ORE 

UTAH 

WYOM 

MICH 



OHIO 

VWA 

ILL 

IND 

Wise 



COLO 
IOWA 

KANS 
MO 

NEBR 



SDAK 
Nova Scotia 



CALL 


SCORE (pts) 


WAIKMP 


48.723 


fixed 


W1APU 


4J50 


fixed 


WIAOE 


65.860 


fixed 


K1IIK 


21.930 


fixed 


WA2DFC 


47,125 


fixf»fl 


K3NVC 


1fiJ20 


portable 


W2MEi 


204,428 


fixed 


W3HQU 


192.375 


fbsed 


W3ARK 


150,960 


fixed 


W3ZUH 


8,601 


mobile 


WB40GW 


433,048 


fixed 


W40ZF 


19.313 


mobile 


WB4QGN 


355,616 


fixed 


W4KFB 


10.296 


fixed 


K4ENL 


83,240 


fixed 


W40IVtW 


2,600 


portable 


W4MCQ 


11.766 


mobile 


WB4CQC 


8.662 


fixed 


WB4WHE 


2,904 


portable 


W4KIVIW 


2,640 


fixed 


W5RUB 


68,425 


fixed 


W5RPJ 


22,620 


fixed 


WA5KQD 


438,658 


mobile 


W6CLM 


7,068 


fixed 


WA0KXJ 


220,869 


portable 


W60KX 


5,974 


mobile 


W7GHT 


122,2ae 


fixed 


W7JYW 


14,784 


mobile 


WA7G00 


108,624 


fixed 


WA7G00 


6.600 


mobile 


W72C 


24,072 


fix^ 


WAOTZA 


4,032 


mobil:e 


wcacAL 


15.554 


fixed 


W8KPK 


2 J 42 


portable 


W9CXS 


37.833 


mobile 


K8QWY 


161.460 


fixed 


W8RYP 


24,030 


mobile 


W4UM 


4,056 


portabte 


W9AXT 


11.004 


fixed 


K9UKM 


140.750 


portable 


WA9WIF 


5,610 


iriobile 


W9PJT 


117,700 


fixed 


K9DAF 


53,428 


portable 


WB90NA 


16,737 


mobile 


WBCJGT 


7,866 


fixed 


W0II 


10,560 


fixed 


K0DEQ 


78,522 


mobile 


KODEQ 


17,995 


mobile 


K0LIR 


40,584 


fixed 


W0OWS 


24, 2y/ 


mobite 


WOQNP 


1.998 


fixed 


WB90E0 


27,951 


portable 


K0DEQ 


29.631 


mobile 


K0DEQ 


1.652 


mobi le 


VETAHG 


17 765 


fixed 



Of facsimiles together with an SASE 
must be mailed no later than June 
15th to: Peter Kragh W1AYK, 170 
Summit Avenue, Ramsey NJ 07446, 
AU band/mode actmty is urgentfy 
needed from the counties of Benning- 
ton^ Caiedonia, £ssex^ Grmid Hie and 
Orie&ns. Anyorm ifiterested in port* 
abie or mobife operation is ssked to 
conuct W1A YK or the CVABC. 

YL INTERNATIONAL SSBers 
QSO PARTY 

Starts: 1901 GMT Friday, 
May 14 

Ends: 1900 GMT Siinday, 
May 16 
All bands will be used on CW and 
phone and the same station may be 
contacted on different bands for 
contact points but not for country 
muiiiplier. Use country multiplier 
only one time* The QSO Party is in 
three categories: DX/WK teams^ 
YL/OM teams, single operator. IMon- 
members are welcome to participate 
and QSO party logs will be accepted 
for SSBers awards in lieu of OSLs. 
EXCHANGE: 

Name, RS(T), SSBers number (send 
no number if no n- member), coyntry, 
state, partner's caU (if no partner leave 
blank}, 

FREQUENCIES: 

CW: 356&, 708S, 14070, 21070. 
Phone: 3873. 7273, 14333. 21373, 
28673, 

Some European stations cannot work 
In the US phone band on 80 or 40 
meters; when calling them please 
announce that you will tune around 
3775 or 7090. 
SCOBINO: 

Contact with SSSer member on same 
continent = 2 pts phone, 4 pts CW, 
Contact with SSBer member on 
different continent = 4 pts phone. 8 
pts CW, N on mem bar contacts = 1 
point phone. 2 ptsCW. Multipliers are 
number of different DXCC countries 
^must be YL-ISSB members), US 
states, DX/WK teams, and YL/OM 
teams regardless of bands. Final st^re 
Is total QSO points times total multi- 
plier. 

AW A BOS: 

Plaques will be awarded to the highest 
individual score. DX/WK teams, and 
YL/OM teams, as well as to the 
highest score single operator* Certifi- 
cates CO first and second place m 
country and state. No certificate to 
plaque winners. 
CATEGORfES: 

DX/WK team - Each team consists of 
a OX and W/K SS8 member. Tfie 
team score ts the sum of both 
partners. Score will be determined 
when both logs are received. Jf onJy 
one log is received it will tie scored as 
a sifigEe operator entry. AU stations 
entering the DX/WK team category 
should immediately send a request to 
W7E0L You may cfioose your own 
partner or. if yoy fwve no dioice, 
W7E0I will assign one to you as 
requests are received. All requests 
must be in writing (for records) 
except DX stations who may make 
their requests throtjgh system con- 
trols. One week preceding itie QSO 



Party, teams requesting to be recorded 
may do so through system controls 
during daily operation. No team 
assignments may be made after the 
party begins. 

YL/OM team - Each team consists of 
one YL SSB member and one OM SSB 
member who are related: husband/ 
wife, father/daughter, etc. Operation 
must be from the same QTH. usir^ 
the same ri§ with hjs/fier own call. 
LOGS: 

All logs must show date and time in 
GMT, RS(T), SSBer number, partner's 
calL mode and period of rest time 
Each entry must operate a minimum 
of 6 hours with a mimmum of 6 hours 
rest period for each 24 hours of 
contest period. Logs ^lould be post- 
marked on or before June 30th and be 
received on or before July 1 5th. Send 
logs to: Lyle Coleman W7E0!, 412 - 
I9ih Street SW, Gr^t Falls MT 
59404. 

for free QSO P^tty entry form (no 
fogsK serid sn SASE to: Robert Bekef 
HKAfSCX, 34 White Pine Or,, LiniB- 
ton MA Of 460. 

MICHIGAN QSO PARTY 
Starts: 1800 GMT Saturday. 

May 15 
Ends; 0200 GMT MorKJay, 

May 17 
The QSO Party will be sponsored 
by the Oak Park Amateur Radio Club. 
Phone and CW are separate contests, 
but a station may enter logs for both 
modes. MICH stations may work 
MICH counties for nnuttipliers. A 
station may be contacted once per 
band on each mode. Portable or 
mobile stations may be counted as 
new contacts when they change 
counties, 
FHEQUENCfES: 

CW - 1810. 3540, 3725, 7035, 7123, 
14035. 21035, 21125. 28035, 28125. 
1600 - 1900 GMT try phone: 1B15, 
3905. 7280, 14280, 21380, 28580. 
Try 15 meters on the hour and 10 
meters on the half hour. On VHF, try: 
50.125 and 145.025. 
EXCHANGE: 

RS(T). QSO #, QTH - county for 
MICH stations, state or country for 
others, 
SCQRiNG: 

MULTIPLIERS ARE COUNTED 
ONLY ONCE, MICH stations score 
one point per QSO times the total 
number of states, countries, and 
MICH counttes worked. Non-MICH 
stations score QSO points as: 1 point 
for each W/KWA/WB8 MICH QSO. 5 
points for each WN8 and special 
events station QSO. Total score is 
sum QSO points times the number of 
MICH counties worked (83 max.), 
VHF only eritries score same as above 
except multipliers per VHF band are 
added together for total myl tip lien 
AWARDS: 

Only singte operator stations qualify. 
Trophies will be awarded to MICH 
staik>r& for high CW, high phone, 
high aggregate club score. Plaques will 
go to high Novice, high VHF only 
entry. Certificates to hi^ CW and 
phone in each MICH county. For 
non-MlCH stations, trophies for high 



14 



CW and phone. Certificates for high 
CW and phone in each state and 
countrv. Members of the Michigan 
Week QSO Party Committee are not 
eligible for individuail awards. 
ENTRIES: 

A summary sheet is requested showing 
the scoring and other partiiient infor- 
mation, name and address in BLOCK 
LETTERS, and a signed declaration 
that all rules and regulations have 

been observed. MICH stations include 
name of duh for combined club score. 
Parly contacts do not count toward 
the Michigan Achievement Award 
unless one fact about MICH is com- 
municated. Decisions of the Contest 
Committee are final. Results will be 
final on July 31, 1976 and will be 
maited to all entrres. Mailing deadline 
is June 18th and should be addressed 
to: Mark Shaw WABEDC, 3810 Wood- 
man, Troy Ml 48084. 

WORLD TELECOMMUNICATIONS 

DAY CONTEST 

Phone 

Starts: 0000 GMT Saturday, 

May 15 

Ends: 2400 GMT Saturday, 

May 15 

CW 

Starts: 0000 GMT Saturday, 

May 22 
Ends: 2400 GMT Saturday, 
May 22 
ThJs is the seventh running of this 
annual contest sponsored by the 
Brazilian Ministry of Communications 
and is open to all amateurs. Catet|ories 
include: singie operator multi-band, or 
fixed/maritime mobile stations oper- 
ating from ITT Zones 76 to 90. Use 
all amateur bands from 160 to 10 
meters. Contacts with the same 
station are allowed on different bands, 
but ITU 2ones are valid only once as a 
multiplier regardless of bands. 

EXCHANGE: 

RS{T) plus ITU 2:one number. (Please 

remember that the ITU zone numbers 

are different from those shown on the 
ARRL and CD maps and charts.) 

QSO POmrS: 

Contacts with stations in the same 
country = points. Contacts with 
stations in different country same ITU 
zone = 1 on 10 to 40 meters, 2 on SO 
and 1 60 meters. In another ITU zone, 
same continent: 10 to 20 meters - 2 
points, 40 meters - 3 points, 80 and 
160 meters = 4 points. Another ITU 
zone, another continent: 10 to 20 
meters = 3 points, 40 meters = 5 
points, 80 and 160 meters = 6 points. 

SCORfNG: 

Final score equals sum of QSO points 
times total number of different ITU 
zones. ITU zones only count once 
regardless of bands, 

LOGS: 

Use separate logs for each mode. Logs 
should indicate in this order: GMT 
time, worked station, message sent/ 
rcvd, band, continent, zone (and 
multipliers^ QSO potnts. Logs should 
be postmarked before June 30th and 
sent to: Ministerio das Communi- 
cacoes, Dentel, Brasilia, D. F, Brazil. 



AWARDS: 

The sum of points earned by the top 
five contestants of each country on 
each mode will be used as ''Country 
Points" to determine the winner of 
the ITU trophy. A winner country for 
three consecutive years or five inter- 
spaced years will keep the ITU trophy 
permanently. Gold, silver and bronze 
medals w/ill be awarded to the three 
top world scorers on each mode* 
Diplomas will go to the three top 
scorers in each country, on each 
mode. Countries with a high number 
of logs will be granted diplomas to the 
first three in each call area. 
Clubs and associations wiN be 
included in a special multi-operator 
multi-band category and will not be 
counted for country points. A sflver 
piate will be awarded to the top world 
winners on each mode. Diplomas will 
be awarded to the three top winners 
in each country on each mode. Logs 
must be signed by all participants 
from each club or association. 

WISCONSIN STATE QSO PARTY 
Starts: 0000 GMT Saturday. 
May 22 
Ends: 2400 GMT Sunday, 
May 23 
This is the annual QSO Party spon- 
sored by the Neenah Menasha Ama- 
teur Club, Phone and CW are con- 
sidered separate bands. The same 
station may be worked on eacti band 
and mode. Wisconsin stations may 
work other Wisconsin stations for 
QSO and myltiptier credit. 

FREQUENCiES: 

1810, 3550. 3735, 3900, 7050, 7135, 

7235, 14050, 14280, 21050, 21135, 

21300, 28050, 28600, 50-50.5, 

144-146. 

EXCHANGE: 

RS(T} and QTH — Wisconsin stations 
will send their county for QTH, others 
send ARRL section or country, 

SCORING: 

US and VE contacts count one point 
while DX contacts count 3 points for 
Wise stations. All others score one 
point per Wise contact. Wise stations 
are to multiply the total OSO points 
by the number of ARRL sections 
contacted (74 max.}; KP4, KH6, KL7 
and KZ5 count both as 3 point QSOs 
and as section multipliers. Ail non- 
Wise stations should multipty the 
number of Wise QSOs by the number 
of Wise counties worked (72 max.). 

AWARDS: 

Certificates wiil be awarded to the 
high scoring fixed, portable, mobile, 
Novice, and VHP stations in Wise as 
well as each ARRL section and each 
DX country, 

ENTRIES: 

A summary sheet and station log are 
requested. Indicate each multiplier the 
first time worked. Logs must be 
received no later than June 16 (DX 
logs by July 1L All entries should be 
addressed to: jMeenah-Menasha Ama- 
teur Radio Ciub, Inc., Mark Michel 
W9PJT, 700 Kinzie Court, (Vlenasha 
Wl 54952. 



MiCHtGAN ACHIEVEMENT AWARD 
The Governor of Mich will award 
Achievement Certificates to hams who 
take an active part in telling the world 
of IVIichigan's unlimited resources, 
opportunities, and advantages. Certifi- 
cates are awarded on the following 
basis: 

1. A MICH ham submits log infor- 
mation and names (addresses if 
possible] of 15 or more contacts made 
to out-of-state or DX hams with infor- 
mation regarding IVIICH. 

2. An out-of-state ham, including 
Canada, submits log information and 
names (addresses if possible) of at 
least 5 IVIICH hams who relate facts to 
him about MICH. 

3. A foreign ham, excluding any 
resident of Canada, submits the call 
letters and name/address plus log 
information for at least one MICH 
ham who told him about MICH. 

Only QSOs made during MICH 
Week, May 1 6 - 22, will be considered 
valid. All applications for certificates 
must be postmarked by July 1, 1976 
and mailed to Govornor Wtlliam 
Mi I liken, Lansing fVll 48902. 



OVER FORTY NOVICE CLUB 
Did you know that there is now an 
"Over Forty Movice Club" for Novices 
over 40 years of age? If you know of 
any Novices who meet the require- 
ments please pass the word on to 
them. If you qualify yourself, you are 
welcome in the club* 

An HONORARY Membership is 
also available !o hams of General 
Class and above (any age) who have 
contacted at least 10 Movices since 
January 1, 1976, and can supply a list 
of calls and dates of contact. 



You will receive a handsome certifi- 
cate (suitable for framing} and a mem- 
bership card for your wallet by send- 
ing S2.00j plus 25<^ for mailing and 
handling, to: O.F,rvl,a, P.O. Sox 622, 
Carson City NV 89701, 

The reason for the club Is to offer 
camaraderie to those Novices trying 
for their General in the age group of 
40 and over. Further, to encourage 
the more experienced hams to contact 
Novices and help them to improve by 
benefiting from their extensive ex- 
perience. Last but not least, to maybe 
give a tittle incentive to those of our 
age group who are considering joining 
the rewarding hobby of amateur 
radio, 

WEEKLY PROPAGATION 
A free weekly propagation forecast 
is offered by the Telecommunication 
Service Center. Anyone interested in 
receiving the forecasts should submit 
their name and address to; US Dept. 
of Commerce, Office of Telecommun- 
ications Center, Boulder CO 80302. 
Ask to have your name added to their 
weekly maiting list. The reports 
include a propagation forecast of con- 
ditions for the next seven days, a 
summary of conditions and solar 
activity for the preceding seven days, 
a 12 month running average predic- 
tion of suns pot numbers, and semi- 
monthly revised ionospheric predic- 
tions. 

In addition, the latest six hour 
forecasts may be obtained at any time 
by phoning 303 499 9129. The 
recording is updated every 6 hours, 
seven days a week. Also included in 
the recording are the latest 3 hour 
Index of geomagnetic activity and the 
most recent value of the solar fiux 
reported from Ottawa, Ontario, 
























RESULTS OF THE 1975 DELAWARE QSO PARTY 
Highest scoring DEL station was K3YHR with 16,064 points. Highest 
scoring station outside DEL was WMIUYU with 325 points* 

DELAWARE Stations. .. 



County 


Call 


Total Score 


Mew Castle 


K3VHR 


16,064 




K3HBP 


11,078 




WA3DUIV1 


330 


Keny 


WA3UUN 


3,192 




K3QBD 


544 




W3ZINF 


160 


Sussex 


WN3WIY/3 


ioa 



Out of DEL Stations. 



Sta te/p ro v/co u nt ry 


Call 


Total Score 


Vennont 


WN1UYU 


32S 


Connecticut 


W1TEE 


225 


New Jersey 


WA2VYA 


30 


Pennsylvania 


WA3KFT 


5 


Kentucky 


WB4AJA 


5 


Michigan 


WB8TNC 


45 


JAPAIM 


JA2HLX 


25 



15 



Benjamin F. Jacoby 
88 W. Frankfort St. 
Columbus OH 43206 



The Magnificent Sevens Microhelix 



7 feet, 7 MHz 



The matching of a low 
band antenna of reason- 
able performance to either 



the high impedance of the 
Novice wallet or the much 
less than a quarter wavelength 



size of a city lot is a problem 
which not only faced me 
when my ticket arrived, but 




also can crop up on field day 
or in portable operations. 
When you only have room for 
a ten meter antenna and most 
Novice activity is on 40 and 
80 meters, obviously you 
need a little of that spirit you 
sometimes hear from an old 
timer when he recalls the 
days when a rig was improved 
by rebuilding^ rather than 
giving up two months pay for 
another brand or later model. 

Clearly, for a single band 
antenna, the frequency range 
of interest is quite narrow, 
covering 500 kHz at most and 
extending only 50 kHz (if 
only the Novice portion of 
the band is tuned). It is well 
known that an antenna whose 
size is a small fraction of a 
wavelength can provide an 
output equivalent to the full 
sized version, provided it is 
properly matched and losses 
are kept low. As the size of 
an antenna is reduced, a 
reactive component of the 
driving point impedance 
appears^ and must be can- 
celled by one of opposite sign 
to leave the purely resistive 
radiation resistance term. A 
further complication is that 
as the antenna is made 
smaller and smaller the 
reactive cancellation b^^omes 
more and more frequency- 
dependent, requiring a 
'* tuning" of the antenna as its 
operating frequency is 
changed. 

Another undesirable side 
effect of the reduction in size 



t6 



"BLACK BOX" 



> 

LtNE 




STUFF 



'Tis—r 



^ 




is a reduction in the value of 
the radiation resistance, so 
that, even when the reactive 
components of the driving 
point impedance are 
eliminated, a transformer of 
some kind is required to raise 
the resistive portion from a 
value (in some cases) as low 
as a fraction of an Ohm to 
something suitable for 
matching a transmission (ine 
of reasonable dimensions. 

Thus, the conceptual nub 
of our problem is a black box 
providing the matching func- 
tions necessary to make our 
small antenna have an output 
equivalent to a targe one^ i.e.^ 
to convert the undesirable 
output characteristics to 
those required to match the 
feed line. I found much poo- 
pooing of tuned small 
antennas among amateurs, 
because of the high losses 
found in most standard 
matching networks (although 
W2FM1 has done much work 
with this approach and has 
reported excellent results in 
many QST articles). It seems 
to me, however, that many of 
these problems have arisen 
because attempts were made 
to actually build a "black 
box" full of coils, caps and 
stuff, rather than to allow the 
black box to remain simply a 
concept, which is then used 
as a starting point for think* 
ing. 

Let us do some thinking 
about losses. Losses in the 
antenna itself increase as the 
size of the antenna is reduced 
and h becomes more and more 
reactive. This is because 
increased reactance results in 
larger and larger currents 



a 



TUNE" 



Fig. h The '*nub/' 



flowing on the antenna, 

causing it to act more as a 
heater than an antenna. The 
answer is to make our 
antenna out of some low 
resistance material like silver 
and, further, to increase the 
surface area where the 
currents are flowing as much 
as possible, since healing is an 
1^ R effect and a small reduc- 
tion in current density makes 
for a relatively large drop in 
losses, Hence^ wire is out! 
Large diameter low resistance 
pipe is f/h For experimenting, 
I chose easily soldered copper 
tubing in a relatively inexpen- 
sive and lightweight Yi* size. 
As an aside, 1 would men- 
tion that I once saw an article 
for the construction of a 
small low frequency antenna 
From steel exhaust pipe. This 
is the worst possible choice, 
since it is heavy, hard to work 
with, relatively resistive, and 
throws in, as a bonus, mag- 
netic losses not found in 
non- magnetic metals. If your 
shack is heli-arc equipped^ 
one inch or so diameter alunv 
inum tubing would probably 

PIEACTIVE z 

+ 200JI - 



-20011 - 



SHORT 
ANTENNA 



1 



result in a much lighter 
antenna. 

Our small antenna 
problem is now reduced to 
determining the configuration 
Into which our pipes will be 
soldered, so that the antenna 
wiil become its own impe- 
dance matching network. 
Since it is usually much easier 
to step an impedance down 
(rather than up) without a 
transformer, we can ask, **Are 
there any short antennas 
with resistive termintil impe- 
dances larger than standard 
coax?" An inspection of 
short dipoies, loaded whips, 
etc., is discouraging, but wait! 
Again it's J. D, Kraus to the 
rescue. In his cI^lssic Antennas 
textbook we find that the 
small hcfix can have this 
property. 

An examination of a 
typical impedance plot for a 
helical antenna, as given in 
Kraus and sketched in Fig. 2, 
shows that when the circum- 
ference is on the order of a 
wavelength, the terminal 
impedance is mostly resistive 
and loops around a value 




suitable for matching a 
standard coaxial line for a 
wide range of frequencies 
(producing the well-known 
broadband matching charac- 
teristics), in this size the helix 
radiates along its axis and 
hence is called an '*axial 
mode'' of propagation. As we 
go lower in frequency or 
buitd smaJler and smaller 
antennas, these loops 
suddenly become very large 
and now pass quite quickly 
through the purely resistive 
points. Moreover, the antenna 
now radiates perpendicular to 
(i.e., '^normal to'*} the axis of 
the helix and is thus termed 
the "normal mode*' of propa- 
gation. For normal mode 
operation we are usually 
talking about maximum 
dimensions of less than one- 
half wave. In conclusion, it is 
seen that the normal mode 
helix has two useful operating 
points where the reactive 
impedance is zero: one where 

the resistive value is low 

(which would give rise to a 

matching problem equivalent 

to that of a short dipole), and 

also a high resistance oper* 

ating point with a value much 

greater than standard coax 

(that can easily be matched 
by a tap down arrangement 

so that the antenna can, in 
effect, act as its own 
matching transformer). 

Now that you know where 
on the impedance plot you 
wish to operate, the trick is 
to put that point at the fre- 
quency at which you wish to 
operate- Since an alteration 



FAEOUENCY OOING LOWER 



RADtATtQN 

NORMAL MODE fTTT 
(CmCUMFERENCE LESS THAN 1/2 X) 



AXfAL MODE nTfT^* RAOIATION 
(CIRCUMFEREJ^CE U2 TO OVER (X) 



7511 



R RESrSTiVE PART 



Fig. 2. Helix terminal impedance. 



17 





BALANCED FEED 



SIDE LOOP FEED 



Fig, 3. Feedpoints. 



of the scale of the antenna is 
more or less out, I chose an 
end-loading capacitor (^ 40 
pF) between the two loop 
ends to electrically alter the 
antenna's apparent length. 
This has the disadvantage of 
putting your tuning element 
at the high voltage point of 
your antenna, but does result 
in a small C variation 
(thereby resulting in a wide 
tuning range, which, with 
careful construction, does not 
arc over at Novice power 
levels). Other tuning methods 
are possible, Including 
warping the antenna to alt«^ 
its size (which would 
probably be a superior 
method if high power opera- 
tion were a goal). 

I am not going to be too 
specific on the actual con- 
struction details, since this 
project is basically a junk box 
el cheapo affair. Each loop is 
made by the mathematical 
operation of dividing four 
/2**D 10 ft copper tubes into 
four 30 inch pieces each, and 
using standard 45 pipe fit- 
lings to solder up 2 octagons, 
about 2 meters across. They 
are not completely joined^ 
however. One connection is 
left unmade, where the two 
loops are |oined crosswise by 
a short piece of lube and two 
90*^ elbows to make a 20" 
separation between the joined 
ends of the loops. The other 
ends are stretched out to 39^' 
when mounted and the 
tuning capacitor is connected 
between them. The whole 
works is supported on a mast 
and crossmembers made of 
ABS plastic sewer pipe. I have 
found that the availability of 
sewer pipe and fitting varies 



considerably from time to 
time and from store to store, 
so I leave it to you to 
resonate the bins at your 
local plumbing supply to get 
a combination that will work. 
Metal supports and lowers 
will tend to soak up your 
power, so try to keep them 
away - but if you use much 
pipe as a mast, probably 6'* 
ABS would be better than the 
4" I used. I have survived 
60-70 mph winds on 4" but 
as you can see in the photo 
my mast section is very short. 
As a finishing touch, the 
copper can be cleaned and 
sprayed with clear plastic to 
protect it from corrosion. 

Finally, t would just like 
to say a few words about the 
tuning capacitor, I would 
suggest a plate spacing of at 
least Va inch. This may seem 
largej but remember that it is 
located at a high voltage 



point on the antenna and I 
had some trouble with arc- 
overs in damp weather, A 
vacuum variable would be the 

optimum, but tends to be 
rather expensive {even 
surplus). If you only wish to 
tune the Novice band, a 
tuning motor is not 
necessary^ but I predict that 
if you don't take time to 
install one, later you will wish 
you had (especialiy since I've 
noticed a slight shift of 
tuning point with the 
weather). I used a plastic 
refrigerator box to protect 
the capacitor and motor from 
the weather, and silicon bath- 
tub seal is great for water- 
proofing the lid. In choosing 
a motor you will doubtless 
find as I did thai you really 
need one much slower than 
you would think. My Yi rpm 
still seems rather fast, BE 
SURE THAT BOTH THE 
STATOR AND ROTOR OF 
THE CAP ARE ISOLATED 
FROM GROUND (MOTOR). 
I used plastic for the mounts 
and a ceramic shaft insulator. 
Optimum feed is a 
balanced connection at 
symmetrical points on each 
loop (as shown in Fig. 3) with 
a balun if coax is used, but 
my loop feed to one side also 
seems to work with coax and 
IS cheaper. Good low loss 



connections are also impor- 
tant in this feed network as 
well. 

Now that our basic plan of 
attack is laid out we can 
begin to examine the specifics 
of helical antennas. We note 
that there are several critical 
dimensions suitable for varia- 
tions in experimenting^ 
including the turn diameter, 
the pitch of each turn, and 
the number of turns. Helical 
antennas can be built with or 
without ground planes, but 
since the ground plane is just 
a device used to eliminate the 
construction of the other side 
or "image" of an antenna^ 
and since it has been my 
experience I hat a ground 
plane really has to be large 
and relatively conductive to 
be effective, it seems to me 
that unless you have a copper 
roof it is far easier to just 
build the image structure 
than to construct a huge 
ground plane to save a few 
feet of pipe. There is a rela- 
tionship between circum- 
ference and pitch which 
results in circular polarization 
and is given in Kraus as 

CX = 2 Sx, 

where Cx and Sx are the 
respective circumference and 
pitch in fractions of a wave- 




18 



length (but I see no special 
advantage in insuring circular 
polarization for amateur use). 

The final choice of circum- 
ference, pitch, and number of 
turns now becomes a matter 
of experimentation and the 
antenna "arts." As a rule of 
thumb, it probably pays to 
make the diameter as large as 
the mechanics of mounting it 
allow and, for simplicity, I 
chose n equal to one (i.e., one 
turn on each side). The pitch 
can go from zero to any 
reasonable value, and it is 
interesting to note Ihat in this 
light the mysterious DDRR 
antenna would appear to be 
nothing more ihan a normal 
mode helix of pilch zero with 
a ground plane. The pitch on 
my final antenna version was 
determined experimentally 
and was used only because it 
seemed to work the best, 
rather than because of some 
long-winded theoretical justi- 
fication. I used small K" 
copper lubrng for my feed 
connections. 



35 pF— 

CEfiTER 




C**05S STRUCTURE FOR 
ADDED STRENGTH IF REQ'D. 



e:ach section 30 in. long 



Fig, 4. Forty meter norma/ mode helix. 



The antenna pattern is 
directional, having a figure 8 
dipole pattern when mounted 
with the helix axis horizontal 
and a low angle omnidirec- 
tional radiation when 
mounted with the helix axis 

vcrticaL For all around use 
with both high and low angle 
radiation, the horizontal 
mounting is best, while for 
DX a vertical axis mounting 



with the antenna J4 wave 
above the ground should give 
optimum results. 

Th? swr of the antenna 

should be less than 2 over the 
entire Novice band and 
should be phenomenally close 
to 1 at the frequency to 
which the antenna is tuned — 
if your matching tap is 
properly located. 



I have compared this 
antenna to a wire dipole and 
found it to be only a little 
over one dB down. Here in 
the city, however, the big 
problem is not signal but 
noise^ and the helix clearly 
had less noise pickup than the 
dipole. Weak signals that were 
nearly obscured by noise with 
the dipole were easily copy- 
able with the helix. * 



W6YGN 

HANK HENNES 




WB6DAP 
FRED K.SCHMIDT 




SMITTY'S RADIO, 221 E. NEWBURGH AVE,, 
AZUSA, CALIFORNIA, PHONE: 213-334-9817 



ALL AMATEUR RADIOS — MARINE AND 
AUTHORIZED YAESU DEALER 




REOS 



LICENSED TECH. ON HAND 

FOR ALL WARRANTY WORK 

W6YGN - HANK 




CALL FOR FREE BOOK AND PRICE LIST OR WRITE. 



19 







FACTORY DIRECT ONLY" 



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^ SPRING SPECIAL 



1. 
2. 
3. 
4. 
5. 
6. 
7. 

a. 

n. 

12. 

13. 
14. 
15, 
16. 
17. 
18. 
19. 
20. 
21. 
22. 
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Day 
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On« priority Channel 

S«l«ct9blfi 1 or 10 Watts Out 

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455 KHz Caramic Fitte-r 

Numerical Read-out on each Chin net 

BLiilt'Jn Adjustable "Torw- Burst" Gandrator 

Front Panel Tona Sufst Control 

Accepts Wtlson 1402 Bt 1405SM Ktals 

tfidlvlfluat Trimmer Capadtar$for both JX/RK 

Mosfet Front End 

Hetical Re&on^tor 

High VSWn Protection Circuit 

Rt versa Polarity Protflction Ctrcyit 

F4BFM - 1& KH2 Chanfiel Separation 

External Speaker Jack 

Butlt'in Speaker 

Dynamic Microphone Included 

Mobile MoMnttng Bradcet Included 

Frequency flaryga 144-148 MHz 

614" W K 216"H X 9^^"D 

Weiflht: S:^^ lbs. 

Power Requirements: 

Source; 13.S VDC±10% 

Receiver .45 A 

Transmit: 2.6A (lOWL .7A (IW) 

SPECIAL INCLUDES: 

A. WILSON "WE-224" 

B. MOBILE MIKE 

C. MOUNTING BRACKET 

D. 146.52/52 SIMPLEX CRYSTALS 

E. TWO PAIR TX/RX CRYSTALS 
OF YOUR CHOICE. 

1 Co mm on Repeater Frequency 

only) 



SPRING Special on 
Wilson Hand Held 220 and 450 






2202 SM 

FREQUENCY RANGE 220 - 225 MH; 



• Individual Trimm=ri <irt All TX/ftX Cryitals 

• All Cryttjii Plug In 

• 12 KHz Ceramic Fi|t*r 

• 10.7 and 4 55 KC IF 

• .3 Microvolt Seniltlvltv far 20 Db Quitting 

• weight- 1 lb. 14 ox. leti Battery 

• B4tt«ry Indicator 

• Si£«: a 7/8 X 1 3/4 K 2 7/fl 

• 5w4tchdbl« 1 Si Z,^ Watii Otitpul 
& t2 VDC 

> Current Ortini RX 14 MA TX &D0 MA 

> MlErOtwit^h M^k« eutton 
■ UnbreAkaij'le Lexan^ Case 



USES SAME ACCESSORIES AS 1405 
INTRODUCTION SPECIAL 



$ 



239 



95 



INCLUDES 

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2. Flex Antenna 

3, 223.60 Simplex Installed 




4502 SM 

FREQUENCY RAKGE 420 • 450 MHz 



& Ctiann&l Opefation 

Individual Trimmer^ on all TX/RX Crystals 

All CrystalE Plug In 

12 KHz ceramic Filter 

10.7 and 455 KC IF 

.3 Microvolt Seniitivity for 20 Pb Quielins 

Weight: t m, 14 D£. leii B:attery 

Batt«ry indieattir 

Size: S 7/a H 1 3^4 K 2 7/i 

Switcltable 1 & 1.B Watt} Output 

<i 12 VOC 

Current Drain: RX 14 MA TX SOO MA 

Microswitch Mike Button 

Unbreakable ]-exan€i Caie 



USES SAME ACCESSORIES AS 140S 
INTRODUCTION SPECIAL 



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2. Flex Antenna 

3. 446.00 Simplex Installed 



HAND HELD 

ACCESSORY 

SPECIALS 

NOTE: 

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PRICE AVAILABLE 

ONLY AT TIME OF 

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DESCRIPTION 



SPECIAL 
PRICE 



BC1 -BATTERY CHARGER $29.9S 
BP ' N l-CAD BATTE R Y 

PACK..*K, ,.*,...... 10.9S 

LCI * 1402 LEATHER 

LCZ - LEATHER CASE 

FOR 1405. 2202, 4Sb2 ,., . a.SO 

SM2 ' SPEAKER MIKE 

FOR 1402 AND 1405 .34.93 

TEl - SUB-AUDIBLE TONE 
ENCODER INSTALLED .... 34.»3 
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INSTALLED (WTth Purchase) 4^9.99 
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ir XT AL FILTER INST. .*. . 8.9$ 
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(Common Freq. Only) > > * '^ • ■ . S^OQ 




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BATTERY CHARGER 



1402SM 

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144-148 MHz 




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1402 SM 

B Cliannel Operition 
Indivicjuat Trimmers 
on all TX/RX Crystals 
All Cryitals Plug In. 
12 KHz Ceramic 
Fitter 

tO.7 IF and 455 KC IF 
<3 MicroYOlt Senittivity 
for 20 dB Qiijetjn§ 
Weigtit: 1 lb. 14 oz. 



1405 SM 

6 Channel Operation 
individual Trjmmerf 
on all TX/RX Cryitali 
All CrystaJs Plug In 
12 KHi Ceramic 
Filter 

lO.Tand 455 KC IF 
.3 Microvolt &cniitfvity 
for 20 dB Quieting 
Weight: 1 lb. 14 ox. 



Ie» Battery 




less Battery 


* S-MeCer/Battery 


* 


Battery Indicator 


Indicator 


• 


Size! S 7/S X 1 3/4 


• Size; t 7/t x 1 7/B 




% 2 7/S 


K 2 7/S 


• 


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« 2.5 Watts Minimum 




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Output 9 12 VOC 




Output « 12 VOC 


• Current Drain RX 


« 


Current Drain: RX 


14 MATX SOO MA 




14 MA TX 400 MA 


• Micros witch Mike 




(IW) 900 MA (SW) 


Button 


* 


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Button 




• 


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Ca^e 



Optional 
Touch-Tone Pad 
Shown 



Can be Modified 

for 
MARS or CAP 




H05SM 
HAND HELD 

5 WATT 
TRANSCEIVER 



144-148 MHz 



'239 



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ON EACH 

RADIO 
INCLUDES: 

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Accessory Special Prices Available Only at Time of Radio Purchase. 

BC1 @S29.95. BP@S10.50 LCI @ $8.50. 

SIVI2 @ $24.95 TE1 @ $34.^. (SPECIFY FREQUENCY 



LC2 @ S8.50. 



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.TX or RX XTALS @ $3.00 ea. 



» 

INSTALL XTALS @ S7.50/Radio. 



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73 








The 450MHZ-FM game now has one on base! ICOM is on with the first 440-450 radio built 
specifically for base operation, the IC-31. You're going to be hearing a lot from this promising 
young newcomer following in the footsteps of that popular veteran, the IC-30A mobile unit 

Impressively built for 26 channels and 10 watts output, 
this unit is the perfect teammate of the IC-30A, which has 
proven itself to be the biggest 450 winner on the road. 
With the S. W.R. bridge built right into the front panel and 
a forward mounted 9-pin socket, the new IC-31 base unit 
provides the flexibility necessary to good UHF operation, 
and its compact size and styling match the other ICOM base radios. 

If you want the number one team, bring it on home with the IC-31. Tryouts are being held at 
your ICOM dealer now. 



■'Vi 




l^_ 






^1 


^ i 1 IW IM 


m m 








2 




60*. J t VOL. 

* * 

* * 
« 4 


R 


) 



Frequency Range 
Channels 
Power Output 
Sensitivity 

Bandwidth (Transmftted) 

Size 

Weight 



440-450MHZ 
26 

Hi to Watts, variabie to 1 Watt 
.4 microvolts for 20DB quieting 
.3 microvolts for 12DB SINAD 
15KHz with 5KHz deviation 
11 1x230x260 (dim. in MM 
7.2 kilos 



VHF/UHF AMATEUR AND MARINE COftflMUNICATION EQUIPMENT 




ICOM 



Distributed by: 



ICOM WEST, INC. 

Suite 3 

13256 Northrup Way 
Bellevue, Wash. 98005 
(206) 747-9020 



ICOM EAST, INC. 

Suite 307 

3331 Towerwood Drive 
Dallas, Texas 75234 
(214) 620-2780 



CURRENT PROFILE 




Eugene G. Preston WA5FGC 
906 Cedar GIbu 
Austin TX 7S74S 



Fig. 7. First allband antenna. 



An Allband 
Inverted Vee 



An allband antenna 
system has usually 
meant an antenna farm. The 
original objective in this case 
was to have just one antenna, 
without loading coils or traps, 
that would fit in the re- 
stricted space at this QTH, 
yet be able to operate effi- 
ciently on all the high fre- 
quency ham bands. The task 
did not appear to be easy. 

Several antenna systems 
described in the ARRL 
Antenna Book were success- 
fully used during the last three 
years, but each had some 
problem that would finally be 
cause for rejection. The main 
problems encountered were rf 
burns from touching the rig 
while operating, arcing, cotl 
overheating, the need to 
slightly retune the transmatch 
after QSY, and poorer signal 
reports when compared with 
an ordinary dipole. The 



decision was made that the 
antenna system should incor- 
porate the following charac- 
teristics: 

1. A single section of 50 
Ohm cpax from the trans- 
mitter to some remote point 
helps minimize rf problems in 
the shack, especially if the 
coax is buried for several feet. 

2. A single section of open 
wire transmission line would 
be used as a matching 
element. The only adjustable 
connections to this line were 
to be a jumper or shorting 
element and the coax itself. 
Series switches, shunt 
matching stubs^ and shunt 
variable capacitors were ruled 
out. 

3. The antenna was to be a 
single inverted vee. The open 
wire line would feed the 
inverted vee in the center to 
maintain an almost balanced 



radiating system. 

Two anterina systems were 
developed and tested. Figs. 1 
and 2 are schematic represen- 
tations of the two systems, 
showing dimensions of the 
eleme^nts and the coax tap 
location for operation on 
different ham bands. Figs. 3 
and 4 show swr curves asso- 
ciated with Figs. 1 and 2, 
respectively. The center fre- 
quency of alt these curves can 
be easily shifted by relocating 
the coax tap point. 

There are three different 
ways the open wire line can 
be used. The first matching 
technique is shown in Fig, 
1 A. Short dipoles can be 
easily resonated by posi- 
tioning the jumper at the 
maximum current point on 
the line. The coax feed point 
for 50 Ohms will be a short 
distance from the jumper if 
the current in the line is targe. 



This method simply makes 
the line look like an auto- 
transformer, A perfect match 
can be obtained for a specific 
frequency, but the antenna 
has an undesirably high Q. 

The second matching 
technique is shown in Figs. 
1 B and 1 C. This is the best 
and most interesting 
matching technique. The 650 
Ohm open wire line has an 
almost magical ability to 
match an inverted vee of any 
length if the inverted vee is 
not too short at the lowest 
desired frequency. Equations 
for half wave and quarter 
wave matching are well 
known for cases where the 
antenna is a half wave or full 
wave inverted vee^ respec- 
tively. What is not so well 
known is that the line will 
also match any other antenna 
length provided the length of 
one leg of the inverted vee 
and the length of the tine sum 
up to an odd multiple of a 

quarter wavelength. This fact, 
which was discovered by 
experiment, is the basis for 
the success of this unique 
matching system. From a 
reactive standpoint the length 
of the antenna is no longer of 
significance since a line length 
can always be found to com- 
pensate for the antenna reac- 
tance. 

The third matching tech- 
nique is shown in Figs. 2A 
and 2B. The coax feed point 
is put further down the line 
than the maximum line 
current location. This 
increases the resistance X^ 50 
Ohms but also introduces 
series inductive reactance. A 
variable capacitor is intro- 
duced in series with the coax 
and line to tune out the 
inductive reactance. In Fig. 
2B a shunt capacitor makes a 
voltage divider if the resis- 
tance is greater than 50 
Ohms. Notice the, highly use- 
ful double resonance con- 
dition produced by this 
circuit as shown by the sv^/r 
curve in Fig. 4B. 

Construction of this 



22 



CURRENT PROFILE 



50 ft. 



50fT, N0,l4Cu 



a li 



30 ft. 



44ft 



50 ft. 



^7 In. 



A 

y SEE A-A 

A 



:/:^'— 




20 20M 




2C 40M 



J 




A 
A 



OR 



DETAIL A-A 80M 



-4 — 



C3 



2 A 



2B 



Fig. 2, Second all band antenna. Note: A jumper placed !4X 
down the line may Improve the swr on 20^ 15 and 10 meters. 



2.0 



SWR 



1.5 



1,0 
3.6 



ZOt- 



SWR 




FfO 3A 



1 



FREQ CMHi) 



3.9 



F/G3B 




FIG I DIPOLE 



COAX FED DJPOLE 



7.1 Z2 

FREOCMHz) 



Fig. 3. Swr curves for Fig, /. 



antenna system is simple 
since tuning is done after all 
elements have been erected or 
instaifed. The inverted vee is a 
100 foot roll of number 14 
copper wire thait was cut into 
two 50 foot sections. The 
open wire line was made from 
another TOO foot roll of 
number 14 copper wire. The 
tower used for center support 
was constructed from thre^ 
1 8 foot, 2x4 sections of 
wood and has a height of 30 
feet when raised. The open 
wire line is brought down the 
tower using TV type standoff 
insulators for support and 
spacing. They are screwed 
into the wood to 
six to seven inches 
between the open 
wire conductors. The number 
of supports should be 
minimized to reduce losses 
from leakage currents. Also, 
the TV type supports will 
need additional insulation if 
arcing is observed. A one inch 
length of RG/8 insulation 
slipped into the TV spacer 
with the number 14 wire run 
in the center of the insulation 
has worked well for me, even 
in rainy weather. Since the 



directly 
provide 
spacing 



open wire line is longer than 
30 feet, it is continued along 
the side of the house with the 
same construction techniques 
just described. 

Several months' operation 
on the air providing signal 
strength comparisons with 
other hams and the ability to 
be heard in pileups was con- 
vincing evidence that this 
system performs as well as a 
farm of dipoles. Although the 
antenna shown in Fig, 2 tunes 
broadly on 80 meters, the 
shorter antenna in Fig, 1 
produced comparable reports. 
The Fig. 1 antenna would be 
ideal for the Novice who 
wants to operate on 80, 40 
and 15 meters with a single 
40 meter dipole but is 
restricted to a narrow fre- 
quency range or has 
insufficient property for a 
full 80 meter dipole. The 
antennas and their matching 
systems described in this 
article have eliminated the 
transmatch, reduced rf in the 
shack, reduced antenna 
losses, reduced antenna costs, 
and increased the frequencies 
available from a single 
inverted vee antenna. ■ 



SWR 




2.0f- 



SWR 



SWR 



FIG 4A 

ct" aoopF 



FfG4B 

Ci=l50pF 

C2=^350pF 




4.0 



FIG 4C 




FIG 40 

20M 



J4.I 14,2 

FREQ (MHz) 



14.4 



Fig. 4. Swr curves for Fig. 2. 



23 



73 Magazine Staff 



Squaring the Conical 



If you don*t mind having 
an antenna in your yard 
which looks a bit like a piece 
of modern art, the conical 
mo no pole has some ex* 
tremeiy interesting advan- 
tages. The form described 
here can be constructed inex- 
pensively from TV masting 
and tots of wire. It is ex- 
tremely rugged and storm- 
proof since, as will be seen 
later, it is practically the 
equivalent of having a 30* 
high TV mast guyed by about 
200 small guy wires! 

The conical monopole as 
such is not a new form of 
antenna. It has been widely 
used on VHF and sometimes 
on the HF bands, formed in 
its usual circular shape as 
shown in Fig. T It is a verti- 
cally polarized antenna and 
offers extremely broad band- 
width whiie maintaining a 
low swr. In a sense^ it is 
similar to thiE wide-band 
disco ne antenna, although it 
does not have the large '*top- 
hat'* element required of the 
dtscone. The antenna func- 
tions over a broad frequency 
range because the circum- 
ference of the cone-shaped 
monopole becomes resonant 
at different frequencies as 
determined by the extent of 
the circumference variation 
from top to bottom of the 
monopole. Within the fre- 
quency range for which the 



antenna is constructed^ there- 
fore, it is continuously in 
resonance rather than just 
being resonant in certain 
distinct bands. A typical fre- 
quency range spread for such 
an antenna is about 4:1 
although this will vary a bit 
depending upon the exact 
design used. 

The design presented in 
this article covers basically 
from 80 through 20 meters. 
However, it will show good 
performance up to about 19 
MHz or so. So, if the 18 MHz 
band ever becomes a reality 
in the distant future, the 
antenna would, in fact, con- 
tinuously cover 5 amateur 
bands (80, 40 and 20 plus the 
proposed 12 and 18 MHz 
bands). The antenna is fed 
directly with 52 Ohm coaxial 
cable and requires no addi- 
tional tuning devices. A 
simple loading coil can be 
switched in at the base of the 
antenna to extend its range to 
1 60 meters, if desired, and it 
should show very creditable 
performance on this band - 
especially if a reasonable 
ground radial system is used. 
If one has the real estate 
available, more than one 
antenna could be used to 
form a directional array by 
proper phasing of the current 
fed to each antenna. Since 
the spacing of the antennas 
would be fixed physically but 



vary electrically on the 
different bands, this would 
mean, however, that the 
phasing lines between 
antennas would have to be 
changed on each band. 

The basic conical antenna 
as shown in Ftg, 1 wou!d 
seem to present some almost 
impossible constructional 
aspects on the lower fre- 
quency bands if the classic 



formula dimensions of the 
antenna were maintained. For 
instance, for basic 80-20 
meter coverage the overall 
height has to be 32 feet. This 
dimension is not impossible, 
of course, but the upper and 
lower rings of the monopole 
have to be about 6 and 18 
feet in diarneter, respectively. 
Constructing an 18 diameter 
ring of lightweight tubing is 



5ofl 




Fig. L Basic di scone monopole antenna is frequency indepen- 
dent over about a 4: 1 frequency range^ 



24 



hardly a simple matter for the 
average amateur. 

The circular form of the 
antenna is important if abso- 
lutely omnidirectional radia- 
tion characteristics are to be 
achieved. But, only a slight 
deviation from this charac- 
teristic wit! result if the 
antenna is made square in 
shape instead of perfectly cir- 
cular. The radiation from the 
corners of the antenna will 
suffer a bit (perhaps 3-5 dB 
down), but it should not be 
difficult for any amateur to 
orient the antenna with the 
aid of a great circle map 
centered on his QTH such 
that these points fall into 
areas which are of minor 
preference. The other advan- 
tages of this form of antenna 
should far outweigh this 
disadvantage. 

A "squared-ofP* conical 
monopole for 80-20 meters is 
shown in skeleton form in 
Fig, 2, Not every wire is 
shown for the sake of clarity. 
The total mast height above 
the base insulating section is 



30 feet and may consist 
simply of telescoping TV 
mast sections. The height 
from ground to the insulating 
section may be 2*3 feet. The 
upper square is located about 
2 feet from the top of the 
mast. Each side of this square 
is 6 feet long- The square can 
be constructed from metallic 
tubing^ but a better choice is 
probably PVC plumbing type 
tubing using the right angle 
fittings easily available for 
this type of tubing to form 
the square. Holes are drilled 
through the tubing for each 
wire element and a fixing 
wire placed around the #ntry 
and exit points of each wire 
to keep the overall square in 
place. At the top of the mast, 
each wire element is secured 
to a ring which metatltcally 
connects it to the mast. 

At the base of the 
antenna, four approximately 
6 foot tall guy posts are 
installed spaced 1 6 feet apart 
and centered around the 
central mast. The lower ring 
of Fig. 1 is simulated by an 
imulated wire ring running 



GUYS 




INSULATORS 



6ft MAST (GUYED) 



The conical monopole is a vertically 
polarized antenna that offers extremely 
broad bandwidth while maintainiriga low 



Fig. 2. Squared form of antenna form shown in Fig. J, 
Distance between 6 fool masts is !6 feet. Other dimensions are 
discussed in text. 



around between the four guy 
posts. This wire should be 
particularly taut, and it 
may be advisable to guy each 
guy post in two directions,, 
depending upon the type of 
soil encountered. Each wire 
element from the top of the 
antenna is run through the 
upper square^ then to the 
lower wire ring (where it is 
soldered or clamped to the 
wire ring), and then to a 
collector ring just above the 
insulating section on the 
central mast. The spacing 
between the wires as they 
reach the lower wire ring 
should be about 3 inches, 
Belden copper-bronze 
antenna wire is particularly 
suitable, but any good 
antenna wire of the copper- 
bronze or copperweld variety 
will more than adequately 
suffice. 

The center conductor of 
the coaxial feed line should 
be connected to the wire 
collector ring above the insu- 
lating section on the central 
mast. The shield is connected 
to the mast support pipe 
going into the ground. 
Although this type of 
antenna is less dependent 
upon ground radials than the 
usual type of single element 
vertical antenna, ground 
radials will improve its perfor* 
mance. But, again because of 
its unique design, the antenna 
does not require ground 
radials of the usual length as 
single element quarter-wave 
vertical antennas, A group of 
10-12 radials^ each being 
16-17 feet long, will suffice 
for normal operation, 
although numerous experi- 
ments have shown that a 
greater number of radials will 



improve the low angle radia- 
tion characteristics for DX 
purposes. Experiments have 
also shown that ground radial 
extension in the direction of 
desired DX performance will 
considerably improve perfor- 
mance in that direction. For 
instance, say one does have 
room to bury 16-17 foot 
radials all around the antenna 
but one's particular DX 
interest is South America. By 
making the radials pointing in 
the South American direction 
as long as possible (34 feet to 
i nf in i ty), considerable 
improvement in low angle DX 
radiation in that direction 
will occur. A rough estimate 
is that radials one wavelength 
long in the desired direction 
result in a 3 dB gain at the 
low vertical angles useful for 
DX purposes. 

The squared conical mono- 
pole is certainly not the 
overall answer to HF antenna 
problems, but it does offer 
reasonably omnidirectional 
coverage and coverage of the 
main HF bands usable during 
the present suns pot cycle. 
Since the swr to the antenna 
also remains less than 2:1 
over its design range, it also 
serves as an excellent antenna 
companion to the various 
solid slate transceivers on the 
market which have broad- 
band transmitter output 
circuits (non-tunable). These 
circuits demand for maxi- 
mum power output that the 
antenrta iransmission line 
they work into presents a 
very uniform low swr pattern 
on each of the bands involved 
if the "instant" bandswitch 
advantage of these rigs is to 
be a realistic operating con- 
venience. ■ 



25 



,STAI^D-0FF IMSULATOH 



Secret 

Antennas 

for 

Cliff Dwellers 



J. Craig Caston WA6PXY 
5403 Newcastle Avenue #20 
Encino CA 91316 



There have been countless 
articles published about 
the various antennas that can 
be adapted for those of us 
who live in the v^onderful 
world of ''urbanvilie." 
Whether it has been for con- 
venience or necessity, many 
amateurs today find them- 
selves living In an apartment, 
a small city lot, or the pop- 
ular condominium. 
Admittedly, this kind of 
living has its advantages. But 
one of the greatest disadvan- 
tages for radio amateurs, 
however; is how and where 
are you going to erect an 
effective antenna? 

After moving from a house 
into an apartment, I found 
myself confronted with this 
problem. I learned, some- 
times the hard way, what can 
and cannot be done. This 
article will present various 
configurations involving what 



,«Ol4-N0 56 eWAMELED 



"TrnTTTTTTTTrrfTTTTTTTTrrTTTTTTTrTrTTrTTTTTTTTT? 



Fig, 1. One way to amid publicity is shown here. If possible^ 
wire small enough not to be seen^ but strung low^ will do a 
good job. 



I believe is a functional 
all-band antenna system that 
anybody can use successfully, 
which is something that most 
other articles discussing 
antennas for urban dwellers 
seem to ignore. 

To start, let's be honest 
about one always overlooked 
fact: the utilization of an 
indoor antenna. Forget it 
Unless your dwelling is built 
of woodj it is a totally futile 
effort Modern buildings are 
made of concrete and steel, 
all components that love, to 
block rf. You may occasion- 
ally hear and work somebody 
with an indoor antenna, but 
that kind of situation is truly 
like working into a dummy 
load! 

Even hanging something 
outside a convenient window 
opening will not really 
suffice, especially if you*re 
looking out to an apartment 
canyon like I do. Remember, 
antennas, to work effectively, 
have to be installed clear and 
free of nearby objects. 

Second, if you are 
planning to move into a 
building that requires per- 
mission for an outside 
antenna, and that includes 
most of us^ just ask the 
manager about the possibility 
of erecting one. It took me 
three months to obtain per- 
mission to erect a simple 
vertical, but my persistence 
paid off. If the building's 
manager has misgivings over 
such an arrangement, explain 
to the person carefully what 
you plan to do. In fact, a 



little persuasion on your part 
might turn into a blessing in 
disguise. 

But even if you are not 
plagued with space or per- 
mission problems, and need 
just an effective antenna for 
80 or 160 meters, then I have 
the antenna isr you. What I 
am talking about is the end- 
fed, random length antenna — 
an antenna that is easy to 
construct, and yet so effec- 
tive. 

In terms of cost and 
simplicity, the end-fed is hard 
to beat* However, the only 
time anybody sees the end- 
fed configuration nowadays is 
usually around the Field Day 
site. 

The limitations of my 
home brew vertical led me to 
try the end-fed, random 
length idea, A single strand of 
#24 enameled wire was hung 
out my window, I^d yp the 
roof, and strung over a pole 
to the other end of the build- 
ing, all 200 feet of it. When 
completed, 1 had an all -band, 
end-fedj inverted-vee type 
random length antenna, 
minus the transmatch, for 
$1.29! A real winner in these 
peculiar times of inflation 
and recession. 

Description 

A true end-fed random 
length antenna can be several 
wavelengths long.^ It is not 
necessary that it be cut to 
resonate for any frequency; 
therefore, any convenient 
length will suffice. 

As a rule of thumb, you 



26 



should not make the length 
of the wire shorter than one- 
half wavelength at the lowest 
frequency planned to be 
used. This means that for 80 
meters the antenna should be 
approximately 125 feet long. 
For 40, 56 feet. However^ 
one source states that an 
end-fed can be utilized effec- 
tively down to pne-quarter its 
lowest frequency and still 
work welL^ 

This may sound like a con- 
tradiction to the random 
length idea, but in relation to 
all other frequencies the wire 
will look, you might say^, 
randomly long. 

Installations 

Before erecting the end- 
fed antenna you should first 
plan the site in which it is to 
be strung. Doing so will facil- 
itate the actual erection of 
the antenna, especially if it is 
to be done in a secretive way. 
By viewing the roof and 
designing a mental picture of 
how you want to place the 
wirSj you can easily rearrange 
the antenna in your mind, 
thus avoiding any erection 
problems later on. 

The best method is to have 
the wire attached to a pole on 
the roof^ the higher the pole 
the better. But, if for any 
reason the antenna cannot be 
stirung on the roof, attach- 
ment to an adjacent building 
or down to an open field will 
do just as welL That's the 
beauty of the antenna — its 
versatility. 

IVe already mentioned 
that getting at least part of 
the antenna in the clear is 
probably the most important 
consideration. This fact 
cannot be overemphasized^ 
because the efficiency of the 
whole system depends upon 
the antenna's being in the 
open somewhere along its 
length. Figs. 1 and 2 give a 
couple of ideas on how this 
could be accomplished. 

It is suggested that solid 
enameled wire be used for the 
antenna element. Enameled 
wire is cheap, convenient, and 
it IS easy to handle — you just 



wind it off the roll. Moreover, 
enameled wire can be strung, 
if necessary, without the use 
of insulators because of its 
protective coating. To avoid 
unwanted publicity, #34 or 
#36 wire is a good choice. 
Your decision on the right 
size will depend, again, on 
your own situation. 

Widely different wire sizes 
will have a negligible effect 
on performance. It has been 
proven that wire as small as 
#36 can work well and 
handle high power levels just 
as easily as #12 of #14. How 
far you can go in power on a 
thin wire antenna, without 
damaging it, however, will 
have to be determined experi- 
mentally. 

Where needed, insulators 
can be made of anything that 
insulates. For deceptive pur- 
poses clear plastic or plexiglas 
cut to suit your needs will do. 
Also small diameter vinyl, 
fishing line^ or plastic tubing 
IS a good choice to consider 
since it can be tied to support 
structures easily. 

An effective way to lead 
the antenna up to the roof, if 
you use that configuration, is 
with stand-off insulators (see 
photo). Again, the proper 
choice and placement of 
insulators will depend upon 
your needs. 

One of the nice things 
about the end-fed antenna is 




An insulator on top of a piece of wood stuck into the rain 
gutter is one convenient way to lead the antenna up to the 
roof 



that it requires no lead in. 
One end of the antenna, as 
the name properly says, is fed 
the power. However, because 
different impedances will be 
presented at the feed point of 
the antenna, depending on 
which band you operate, a 
tuner will be required. 

Tuner Considerations 

As you probably know, a 



simple coil and capacitor 
arrangement is all that's 
needed (Fig. 4). If you want 
to spend the money, a com- 
mercial unit will do nicely. 
But constructing a tuner 
yourself can be achieved 
without too much difficulty 
or expense. On power levels 
up to around 200 Watts, a 
broadcast band variable out 
of an old receiver and an 




jif'Hi nn/m Nnfftntufi 



infufff r t f * ^ i t f nuijr 



Fig. 2 Here are three ways an end-fed can be used around a building. 
Note that in at! three examples^ the wire is reasonably clear of objects 
somewhere along its length. 



27 



inductor of about 30 uH will 
do the job. 

A check into a parts 
catalog will list a number of 
coils and capacitors that can 
fit your own needs. My tuner 
uses an E. F. Johnson roller 
inductor #229-203. This coil 
works beautifully. If you can 
pick one up^ it is suggested 
you do so. Unfortunately, it 
has been reported that this 
inductor is no longer in pro- 
duction. A little searching, 
however, might produce one 
at a moderate cost. 

CI is a jphnson type E 
tra nsm i tting capacitor 
#154-1 a It's rated about 350 
pF at 3 kV. These com- 
ponents were chosen with the 
thought of using higher 
power in the future. 

Installation of LI and CI 
into an enclosed chassis ts 
necessary for proper 
shielding. The photo should 
give a good idea of com- 
ponent layout and assembly. 

As an added bonus, 1 
found that my tuner knocked 
out a!! remaining TV I, some- 
thing that apartment hams 
are keenly aware of since 
interferences into just one 
building's TV system could 
easily disturb the viewing 
enjoyment of many people. 

Inside the Shack 

Because of the tuner, a 



good ground system is 
needed. An effective ground 
will help prevent useless rf 
currents from flowing around 
the shack. If a decent ground 
is not used, the operator will 
face problems in achieving a 
minimum swr from his unit, 
[n addition, his equipment 
will develop a condition of 
''biting'' when he touches it. 

Finding a satisfactory 
ground is a difficult problem 
for apartment dwellers. This 
is because the most obvious 
ground systems may not be 
readily available, especially if 
your apartment is several 
stories above terra fir ma. 

One way to "ground" the 
tuner is to use a counterpoise 
or artificial ground. This is a 
wire one-quarter wave long of 
whatever band you use placed 
conveniently around the 
shack. The only drawback to 
this idea, however^ is that to 
be effective at feast one wire 
must be installed for each 
band, I have one counterpoise 
in use now. It's cut for 40 
meters even though I fre- 
quent 80 as well. Therefore, 
it's possible that you might 
be able to get by using just 
one counterpoise for two 
bands. 

Another way to help 
eliminate stray rf currents is 
to try to terminate the 
antenna wireJ at a current 



-AMTENHtA- 



f fh 



..X^IzL 



TO TRAMSMITTER 



.CI 




A look at the home brew 
Insulators^ and the placement 
chassis. 

loop. This involves using a 
length or antertna cut for 
your favorite band at least 
one -quarter wave long or 
multiples thereof,: This mini- 
mizes the amount of rf intro- 
duced into the shack. Doing 
this is not imperative, but it 
might aid in stopping a hot 

rig. 

If you can connect the 

tuner with a short piece of 

wire to some grounded water 

pipes or something of similar 

nature, then you're in good 

shape. In addition to the 

counterpoise, I have a wire 

running from the sha6l< Ind 



grojivd- 

■^ WfliTER PIPES 
BAThfROOM 
PUliMBFriG. 
ETC. 



\/4 WAVE C0litJTERP03Se-O*JE 
NEEDED FDR EfiCH B<1ND 



F/g. 1 C/ — 350 pF single gang variable capacitor; LI — 20-30 
uH inductor (E, F, Johnson #229-203 roller Inductor 
suggested). 



transmatch. Note the standoff 
of LI and CI in the spacious 

connected to the pipes in my 
bathrtjom shower. Oufte sur- 
pri singly^ this eliminated 
most of my ground problems* 
Those wishing additional 
information can find an 
excellent article on tuners in 
the December, 1974 QST by 
D]2LR/W2\ or consult The 
Radio Amateur's Handbook, 

Conclusion 

The performance of the 
end- fed system at my QTH 
has be^n very gratifying. DX 
on 40 and 80 meters has been 
easier to hear, while signal 
reports with only 200 Watls 
of power have been excellent 
from stateside stations. 

tt*s hop^d this primer will 
guide the amateur in making 
the right decisions involving 
the end-fed concept which fit 
his own individual and unique 
situation, while at the same 
time giving the amateur 
plagued with space and per- 
mission problems a chance to 
enjoy his or her hobby with a 
minimum of difficulty. » 

References 

* The ARRL Antenna Baok^ 13th 
Edition, ARRL, Newmgton CT, 
1974, p. 17S. 
^tbid., p. 178. 
^fbid., p. 179. 

U^r!ch L. Rohde, "Some Ideas 
on Antenna Couplers/' QST, 
December, 1974, pp. 48-52. 



28 



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Pticei aipci m ehmce mtttet^ mrtice 



ip 



One of the most popular 
antennas b the so-called 

'^inverted V," which is 
actually a dipole with the legs 
drooping at approximately a 
45"^ angle on each side of a 
single support. The single 
support is the secret of its 
appeal, because almost every- 
one can find something to 
support this type of antenna, 
as in Fig. 1, where it is 
supported on a TV mast 
pulled up with a pulley. This 
way it can easily be lowered 
for tuning. However, even if 
not on a pulley, it*s quite an 
easy antenna to tune, because 
the legs are so close to the 
ground. 

The ideal inverted V 
antenna would have the 
included angle (a) 90°, and 
the legs in the same plane as 
the lower. It would be a liitle 
better if the top was 
supported about 3' away 
from the metal tower, to 
keep the tower out of the 
field of the antenna. See Fig, 
3. 

However, the antenna will 
work well — even in the most 
unusual configurations. See 
Fig. 2, For example, my avail- 
able yard for antennas is 74* 
X 70', which is no way close 
to the ideal required space for 
an 80 meter V, I have two 
towers, 48 feet apart. Figs. 4 
and 5 show the slope and 
separation of my antennas. 

These antennas have an 
important amount of vertical 

polarization, as when angle 
*V* Is less than 90^ the 
vertical polarization pre- 
dominates, and when il is 
greater than 90° the hori- 
zontal polarization pre- 
dominates. Thus the antennas 
are good DX antennas — 
better than a horizontal 
dipole. They do, however^ 
show many characteristics of 
the horizontal dipole, being 
less subject to man* made 
noise and more to high angle 
radiation than the vertical. 
For example, when I am 
transmitting to KIGZL in 
Berlin, N.H., he says my 
signal is about 20 dB better 



from the inverted V than the 
vertical, but my vertical is 
about 3 S-units better in the 
Antarctic than the inverted 
V. When I am talking to 
W5VSR in New Orleans the 
situation varies. Some nights I 
am better on the V, and some 
nights on the vertical, and 
some nights 1 will fade out on 
one and come in strong on 
the other. 

Although 1 am using 
baluns on both, there might 
be some advantage to not 
using baluns, sinc€ I am in the 



northern part of the country. 
An inverted V without a 
bafun tends to be directional 
toward the side of the 
antenna with the shield of the 
coax connected. Thus the 
pattern without a balun tends 
to be skewed to one side. 
Whether this is an advantage 
or disadvantage depends on 
where you are and what you 
want. I tim of the opinion 
that the balun is unnecessary 
for general use, provided that 
your antenna is resonant at 
about the frequency you 



Jerrald A. Swank W8HXR 

657 Wiilabar Drive 

Washington Courthouse OH 43 J 60 



The Novice 
Inverted Vee 





FANNED AWAY 
FROM TOWER 




work^ and that the coax lead- 
in is a multiple of a half wave 
at that frequency. 

Since I am using baluns, I 
am also using separate feed 
tines to the 40 and 80 meter 
antennas. Without baluns you 
can easily feed both from the 
same feed line, and just 
parallel them, thus saving 
quite a bit in these days of 
high costs (by not using two 
baluns and perhaps a hundred 
feet less of coax). 

When you tune up an 
inverted V you will find that 



3ff Xlfri. 
AWQLE iROfi 



INSULATOR-*-, 




Ffg. I 



Fig. 2 



Ffg, 3, 



30 



-*-r£NCE 



■\^ 










1 

® 


^^^■""^ 






96* L J, 


» 135' 

\40 METER 
\ ANT 








^^ 



GO METEPt AHtEHHA 



PLAN ViEW 



Fig, 4, 



it is very easy to tune and 
very easy to understand. It is 
best to cut it a little long, 
perhaps as much as two feel. 
When you measure it with ^n 
swr bridge it may look like it 

will never tune, but start 

taking off about six inches at 
a time and measure the 
bottom of the range you 
want. When it starts to go 
down toward 1:1 measure 
about 100 kHz on each side 
of the desired frequency, and 
find where the center of the 
range is. Don't worry if it will 
not go lower than 2:1 just 
find the center. When you 
have it centered, then start lo 
close or open the angle at the 
bottom, and raise and lower 
the legs a little. This wiil 
improve the swr, and if you 



have enough room you can 
get it right down to 1:1, At 
this point you will find it 
quite broad tuning, and 
probably it wtH cover the 
whole range you want with 
swr less than 1:1.5. 

Of course, if you have to, 
you can pull up an inverted V 
into a Iree^ or on the side of 
your house, or on a piece of 
masting attached with TV 
hardware lo a soil pipe or 
chimney. 

I think that every ham 
should have both a vertical 
and an inverted V or dtpole. 
The signals often swing 
greatly from one to the other, 
1 had a ham in the Antarctic 
tell me one night that he had 
two receivers tuned to me, 
one on a vertically polarized 



antenna and the other on a 
horizontally polarized 
antenna. He put one on each 
side of the room so that he 
was sealed between them and 
he said it was t)e3UtifuL The 
signal would fade from one to 
the other and he never missed 
a word. 

I have given yuu the 
figures for the Novice bands, 
.ihhough my antennas are 
luned several inches shorter 
for where I work. 

The regular dipole at the 
center has an impedance of 
about 72 Ohms, so it is better 
suited to RG11 or RG59. 
However, the downward 
slope of the legs on an 
inverted V makes it an 
excellent match for RG8 or 
RG58. 



Incidentally, at Novice 
powers don't waste your 
money on RG8. RG58 is 
quite adequate. The power 
rating of RG58 at 30 MHz is 
430 Waits, and the loss of 
100 feet of RG58 at 7 MHz is 
just one dB greater than RG8, 
That means you would barely 
be able to tell the difference. 
At 3.7 MHz it would be even 
less. 

Incidentally, remember 
that you can use the 40 meter 
inverted V on 15 meters, and 
the 80 meter inverted V on 
10 meters, so you can have an 
al! band Novice antenna with 
a single feed line. 

Also, if you have to put up 
a push-up mast or pole you 
can use the two inverted V 
antennas as guy lines. ■ 



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tlO Bngineerinq 
9503 G^mbels QnaU 
Austin TX 7S75S 



Closed Loop 



Tuning Yagj-Uda beams 
and quads can be a very 
time-consumiRg task, requir- 
ing many man-hours to per- 
form. Usually several helpers 
are needed to make adjust- 
ments and to lake field 
strength measurements, t 
have developed a technique 
v^hich requires only one per- 
son to successfully tune an 
antenna with the aid of a 
couple of pieces of equip- 
ment. The method developed 
uses an rf source in the far- 
field and the station receiver 
as a sensitive field strength 
measuring device. A circuit is 
connected from the receiver 
to a speaker, which^ in turn, 
can modulate a small 100 mW 
transmitter. The receiver for 
the 100 mW transmitter is 
carried by the person making 
adjustments on the antenna, 
Thus^ a closed loop feedback 
system is used to permit optr- 
mum adjustment of the 
antenna. As a bonus, the far- 
fjeld signal source can be used 
to make pattern measure- 
ments as the antenna is 



SMALL 
AMTEKNA 



>5X 



FAR -FIELD 
TRANSMITTER 



Antenna Tuning 



rotated, the receiver monitor- 
ing relative field strength. Fig. 
1 shows a block diagram of 
the system. 



Circuit Details 

The far-field signal source 
is a smalt, low power oscilla- 
tor (Fig, 2), Transistor Qi is 
used in a Pierce fundamental 
mode oscillator. A diode full 
wave rectifier is used as a 
frequency doubler. A small 
Amidon iron powder loroid is 
used to develop the push /pull 
signal needed for full wave 
rectification. Transistor 02 
acts as an amplifier for the 
doubled frequency. Another 

transformer, T2, steps the out- 
put impedance down to a low 
value. The crystal is chosen 
such that the harmonics will 
fall Within the amateur bands, 
I used a 7060 kHz crystal 
which permits field strength 
measurements at 14,120, 
21 J 80, and 28,240 kHz, The 
output signal is rich in the 
2nd, 3rd and 4ih harmonics 
and produces a strong source 

ANTENMA UNDER 

ADJUSTMENT 

ON TOWER 



for the 20, 1 5 and 1 meter 
bands. The oscillator is 
powered by 2 six volt 
batteries connected in series 
to produce 1 2 volts. Since the 
current drain is tow the 
batteries will last a long time. 
Two wires about 5 feet long 
are connected as an antenna 
to the output of the ampli- 
fier. Ideally, the far-field 
source should be at the same 
height as the station antenna, 
but useful results wilt be 
obtained by mounting the 
transmitter/antenna on the 
top of a tall ladder leaning 
next to a rooL The trans- 
mitter should be at least 5 
wavelengths away for mean- 
ingful results. 

The unit that connects to 
the receiver is a voltage-to- 
frequency converter. The 
voltage developed across the 
meter is used to vary the 
frequency of an audio oscilla- 
tor. The maximum voltage 
developed across the meter 
can either be measured with a 
sensitive voltmeter or be com- 
puted. For the Heath SB-1 02, 




RADIO TELEMETRY-, 
LINK (MM) 

ACOUSTIC I 
UliK 



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f^ECVH 
WITH 
S-M£Ti» 



VOtTAGE'TO" 
FftEOUENCr 
COHVERTEft 



tOOmW CB 
TRANSMITTER 



Fig, h Closed loop antenna adjustment block diagram. If CB radios are not available ^ a two wire 
speaker cable could be run up the tower for momtoring. Far-field transmitter is a milliwatt 
transmitter with harmonics falling inside the 20, 15 and IOmeter bands. 



the internal resistance is TOO 
Ohms^ and the full scale read- 
ing is 1 mA. Thus, the full 
scale voltage across the meter 
is: 

1,00 mAx 100 Ohms = 
100 mV 

The 100 mV signal is 
amplified by a 741 opera* 
t tonal amplifier as shown in 
Fig. 3. The gain of the ampli- 
fier is 40 dB. Thus the S 
meter full scale voltage of 
100 mV would become 10 
volts at the output of the 
amplifier. This voltage is used 
to drive the modulation input 
on the 555 free-tuning oscilla- 
tor. The 555 oscillator 
oscillates al a frequency 
determined by the resistor/ 
capacitor combination con- 
nected across it. The fre^ 
quency of oscillation is given 
by the equation: 



F - 



1.44 



(Ra + 2Rb)C 



For the values given, the free 
running frequency is roughly 
1 kHz, As the 741 amplifier 
drives a current into the 555* 
however, this frequency is a 
little lowt^r than 1 kHz and 
becomes greater as the drive 
current is reduced. Thus, the 
effect is to hear a higher 
frequency for a lower S- meter 
reading, and a lower fre- 
quency as the 5-meter reading 
becomes stronger. The 555 
drives an 8 Ohm speaker. The 
470 Ohm series resistor is 
used to limit the current to a 



32 



FREQUENCY DOUBLER 



AMPLIFtER 



+ I2V 



GND 




I SOU 



SHORT 

ANTEf^NA 



Fig. Z Schematic of the milliwatt transmitter for Ihe far-field source. Yj: 7.00-7.115 MHz; 
harmonics foil within 20m^ 75m and 10m bands; Tj: Amidon Core 750-2, primary 22 turns 
#28j secondary 20 turns #28, center-tapped; T2: Amidon Core T50-2, primary 22 turns #28, 
secondary 5 turns #28. 



Safe value, and yet still permit 
a loud tone to be fieard. 

The tone From the speaker 
is monitored as an indication 
of relative field strength level. 
In the prototype, a 100 mW 
citizen's band walkie-talkie 
was used as a telemetry link 
between the receiver and the 
antenna on lop of a tower. 
The walkie-talkie was taped 
'*on/' and the speaker was 
acoustically coupled to the 
unit. The walkie-tatkie is a 
very good and inexpensive 
wireless telemetry link. Both 
units were bought for less 
than $10 several years ago, 
and similar units are still 
available. Since the distance 
between the walkie-talkies is 
not far, the antennas on the 
units can be retracted some- 
what to limit their range. If it 
is not possible to find any 
walkie^talkieSj then a two 
wire system can be rigged to 
perrnit hearing the speaker at 
the antenna tuning site. The 
wireless approach is better 
because there are no wires to 
get tangled in, and the 
volume of the sound can be 
adjusted on site. 

When coupling the 
volt age- to -frequency Gon- 
verter to the receiver, a 
battery or isolated supply 
should be used to power it. 
This is because the S-meter 
circuit may be at a high 
potential above ground, and 



the return ground on the 
voltage-to-frequency will also 
be at this high potential This 
high potential is called a com- 
mon mode voltage. The 741 
amplifier will not function if 
its common mode voltage is 
too great. If a common 
ground between the cqn verier 
and the receiver Is not used, 
the 741 operational amplifier 
will only detect the differ- 
ential voltage across the S- 
meter and it will not respond 
to the common mode voltage. 

Operation 

The voltage-to-frequency 
converter should be con- 
nected across the S-meter. As 
a signal is tuned in, the tone 
from the 555 oscillator will 
change pitch. The far -field 
source should then be placed 
several wavelengths away and 



tuned in with the receiver 
connected to the antenna. If 
the front-to-back ratio is to 
be optimized, then the adjust- 
ment of the antenna should 
be done to minimize the 
S-meter reading while the 
antenna is pointed away from 
the far-field source. On a 
quad, for instance^ the 
reflector stub should be 
varied until the receiver 
reaches a minimum signal 
strength. The tone from the 
555 oscillator should be mon- 
itored for the highest possible 
pitch. The human ear can 
detect fairly small changes in 
pitch if a continuous tone is 
heard at all times. For front 
gain optimization, the beam 
would be pointed towards the 
source and the pitch from the 
telemetry link would be 
owered as much as possible, 



indicating maximum frontal 

gain. 

Once the adjustments are 

made, the far-field source 
makes ^n ideal reference to 
make relative Field strength 
measurements with. If a cali- 
brated output signal genera- 
tor can be found, then a 
matched S-mctcr reading can 
be taken between the antenna 
and the generator output. By 
plotting the relative output 
level from the generator vs. 
bearing, a polar plot of field 
strength can be taken. The 
S-meter is used solely as a 
matching device, matching 
the antenna output to the 
calibrated generator output. 
It is surprising how uncali- 
brated S-meters are in terms 
of real S units to absolute 
units (an S unit is defined as a 
6 dB change in signal 
strength). For signals which 
barely deflect the S-meter, 
sides of beams for instance^ 
an audio meter may be used 
to match the generator's out- 
put to the antenna's output* 
For antennas such as 
quads it is gratifying to know 
that optimum adjustments 
can be made without a 
number of people needed. 
Since the quad is fairly easy 
to reach from a tower, it is 
very convenient to be able to 
make final adjustments while 
the antenna is in place. I hope 
this method will create 
interest in different 
approaches to solving an old 
problem — how to tune an 
antenna. ■ 



+ 40dB AMPLIFIER 



OSCILLATOR 

TO +I2V 

o 



.&K 



330K 



TO S METER 
TER(W[NALS 



GAIN CdB)-20L0G (R2/RI) 
F= l.44/CRa+2R&}C 




8 OHM 
SPEAKER 



Fig. 3. Schematic of the uoltoge-to- frequency converter, A 100 mV input signal will cause a 
max/mum frequency change at the output of the 555 astable oscillator. 



33 



Edwin T. Kari K2VGD 
63 Cranberry Street 
Central Islip NY 1 1 722 



The 75'80m Broadbander 



Some time ago, I operated 
with an all band multi- 
element dipole antenna. The 
antenna worked quite wefl 
(for a dipole antenna) but 
generally left me in the 
bollom of pileups on 20 and 
1 5 meters. This eventually led 
me to a more competitive 
antenna for the higher fr^ 
quencies. The multi-band 
dipole became redundant 
(and worse yet, tended to 
distort the quad*s pattern). 

However, I wanted to 
increase the bandwidth of the 
80 meter dipole, as my opera- 
tion generally is evenly 
divided between CW and SSB 
operation. After some 
thought, the elements of the 
dipole for 15 and 10 were 
removed, and an attempt was 
made to extend the 20 meter 
element to a length suitable 
for 75 meter operation. 
Reason told me that if you 
could combine dipoles for 20 
and 40, etc., why not 80 and 
75? 

Due to space limitations in 
the K2VGD estate, the 80 
meter antenna was folded 
into a *'Z" shape, to fit a plot 
75' wide. The apex of the 
antenna system was at 30 feet 
and the ends were attached to 
4 tetevision4ype aluminum 
masts, fastened to the fence. 
In atuching the 75 meter 
antenna, I ran the elements 



backwards across the two 
mastSj thus overlapping the 
last 20 feet of each element. 
As one element was insulated, 
no problems with shorting 
were anticipated. The 
antenna is fed with a random 
length of RG*8/U and a 
W2AU balun. 

In testing the design, the 
lowest swr was expected at 
3550 and 3900 (the design 
length of the antennas). Much 
to my surprise the antenna 



exhibited high swr below 
3650, but less than 1.5 to 1 
between 3650 and 4000 kHi, 
with no peaks or dips within 
this portion of the band. 
After several days of experi- 
mentation^ the length of the 
CW section approached the 
length necessary for opera- 
tion at 3400, with the 75 
n>eter antenna cut for 3900, 
Tlie swr plot rs included in 
Fig. 1. 

While I make no pretense 
of having the exact technical 



3Z.5 C40M) 




333 C40M> 



DIMENSIONS ARE 
IN FEET 



Fig, L Vertical view with swr pfoL 



LB 

r4 

1.2 



35003600 3700 3B00 3900 4000 1 7000 TlOO 7200 7300 



explanation of the results, it 
would appear that the ends of 
the antennaj in overlapping, 
inductively and capacitively 
couple the two elements to 
one another in such a way as 
to cancel the reactance that 
would be present at the feed- 
point. Element lengths do not 
appear to follow theory 
exactly, which in all proba- 
bility is due to the fact that 
the ends are ten feet off the 
ground, and the apex is but 
30 feet high, far from the 
ideal 14 wave height. How- 
ever, there has been no 
evidence of very high take-off 
angles, as no difficulty is 
encountered working either 
with the West Coast, Europe 
or even as far away as New 
Zealand on 75 (5x8 in ZL* 
land with 900 W PEP). 

The 40 meter dipole does 
not appear to be affected by 
the 80 meter elements. If 
anything, it seems to have 
broader than normal charac- 
teristics. 

No attempt is made lo 
convince others that "this is 
THE antenna" for 80 meters, 
but rather^ with the declining 
propagation on the higher 
bands, to encourage experi- 
mentation by others in 
I i m i Led space, broadband 
systems. Most of these types 
of antennas use wire ele- 
ments, and thus are relatively 
inexpensive, ■ 



34 



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35 



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IF HE CAN'T SEE THE ANTENNA (OR MOUNT) 
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37 



SSC CortJfliid E. Richmond WICEJ 
43th Transpanalion Company 
APO NY 09454 



The Magic of a Matchmaker 



It isn't necessary to settle 
for an inefficient antenna 
because you don't have the 
space to put up a beam or a 
good high diFK)le, Even if you 
don*i have the lime to put up 
an antennj farm before it's 
time to move, or if the land- 
lord frowns on antennas in 
the yard, you can still put out 
a good signal. The key is the 
use of an anienna tuner. A 
tuner will allow you to use 
almost any length of wire, 
and if you plan ahead a bit^ 
you might even get some 
gain. 

IVe used an antenna tuner 
before, with an end-fed one 
wavelength Zepp on SO, so 
when I needed an all band 
antenna that I could put up 
in the trees, the solution was 
obvious. Unforiunatety, 
someone had relieved me of 
the Johnson Matchbox that 



had served me so well. It was 
necessary to build a tuner 

The unit that I eventually 
built was the product of a 
little thought and a lot of 
SCTOunging, I didn't have any 
of the major parts needed, so 
I had to rely on my friends' 
junk boxes. Vern WB4BER 
came up with a high voltage 
capacitor, and Lloyd 
WA4HYT furnished a 
toroidal tank coil. Armed 
with these parts, 1 decided 
that this was one project that 
would look decent enough to 
put next to the rig, so I 
bought a wooden cabinet 
from Radio Shack ($2,00 on 
the ^*junk" table). 

The special characteristics 
of toroids are well known. 
The one that interested me at 
this point was size, I had just 
bought a used FPM-300, and, 
if I could make a small 
enough tuner, maybe I cou 




put together a suitcase-sized 
station. The cabinet for the 
tuner was in fact just the 
right size to fit in the suit- 
case. 

The circuit I would use 
had already been determined 
by the pans on hand: an "f 
match and variations. With 
this in mind, I built a hay- 
wired matcher to test the 
idea. I didn't know if the 
toroid was suitable for high 
frequency use and had to find 
out before I got the whole 
projecl finished. Feeding a 14 
meter wire, results were sattsr 
factory, and 1 was able to 
match 300, 600 and 2000 
Ohm loads on the five HF 
amateur bands. 

I replaced the original 
front panel on the cabinet 
with a piece of sheet alumi- 
num and mounted the coil on 
it. The coit is actually 18 
turns of #1 2 wire wound on 
two T-250 cores, with two 
lucite end spacers, -and is 
probably much larger than is 
needed for 1 50 Waits of rL t 
mounted the coil to a 12 





"TAPPED" 



position tap switch so that 
the s\vitch and coil would 
make a compact assembly, 
and put the switch right of 
center on the panel. The 
capacitor, which is a 240 pF 
Hammarlund unit^ was 
mounted on a piece of fiber- 
glass on the side of the 
cabinet, so that both the 
rotor and staior were isolated 
from ground. Input and 
output connections were 
placed on the back paneL 

Again, operating results 
were good. However, when 1 
tried to feed the antenna 
through coax, 1 was unable to 
get a match on any band. The 
cure for this was to increase 
the matching circuit varia- 
tions available. This was done 
by wiring in a 3 pole 5 throw 
ceramic switch. This was 
originally a 4 pole unit, but 
between 10:30 and 1 1 :00 pm 
I broke one of the wafers, 
and it took a little thought to 
come up with the circuit 
changes necessary. Inciden- 
tally, besides being ceramic, 
the switches have silicone 




UNKNOWN 




J'v?f^^ ^j:^ — O 



m 



Front view of the Matchmaker, showing controls. 



Fig. h The four different circuits used in the Matchmaker, 



38 



^4 




The rig ready to travel in its suitcase. 



rubber compound placed at 
points where there might be 
arcing to ground. 

The final circyit has four 
configurations and a bypass 
position. It will match high 
impedances, low impedances, 
work as a series tuned circuit, 
and as what I call a lapped 
circuit. Fig. 1 shows the 
individual circuits available, 
while Fig. 2 shows the com- 
plete unit. Note the amount 
of wiring on 5-2, the function 
switch. This is the heart of 
the matcher, and it is a lot 
easier to build if the switch is 
wired prior to being put into 
the cabinet. 

The cabinet is about 
250x175x140 mm (7x9x514 
inches)^ and is made from 
compressed materia) with an 
imitation wood grain surface. 
The front panel is grounded 
to the coax sockets to 
prevent hand effects* 
Obviously this cabinet offers 



no shielding, and a search 
with a wavemeter around the 

operating unit shows strong rf 
fields around the coil and 
switch S-2. Even so, when 
feeding antennas through 
coax, when the coax is 
grounded at the far end, there 
have been no problems with 
rf on the equipment. 

Operating the Matchmaker 
is somewhat different from 
using the Matchbox. I use an 
external swr indicator, which 
is inserted between the rig 
and the tuner. Peak the 
exciter, dip the final, and 
adjust first the inductance 
(switch S'1), then the capaci- 
tance for minimum reflected 
power. It may be necessary to 
re-dip the final, as the tuner 
has some effect on PA tuning. 
Continue adfusting the tuner 
for minimum reflected power 
until satisfied. In some con* 
figurations there will be a 
nice dip in swr, but it will be 



SlA 



J 



LI f5EE TEXT) 



£I2P0S> 




1 



^ 




SIC 




J 




The rig set up in San Diego and on the air. 




Inside of the Matchmaker, Note the fiberglass insulator under 
CI 



Fig. Z The complete schematic of the Matchmai^en 



accompanied by an equal dip 
in forward power! This is 
easy to detect, and means 
that the wrong circuit is being 
used. Just set S-2 to a 
different configuration and 
try again, (f in doubt^ the 
series circuit will always get 
some kind of a match, while 
the* ''tapped" position will 
match whatever the others 
won't. 

An **L*' match circuit 
works best into a high impe- 
dance load. To get this it's 
necessary to use a wire about 
35 to 40 meters long for all 
band operation, t have used a 
19 meter wire, but matching 
was difficult. 

Feeding this type of an 
antenna is problematical. If a 
single wire feed is used you1l 
have rf all over the shack. So 
I use coax. While this sounds 



like some kind of heresy, it 
works. In fact, a couple of 
recent articles have pointed 
out the advantages of feeding 
with coax. If RG-8 is used, 
then the loss in any reason- 
able length wilt be insigntfi* 
cant. Even RG-58 can be used 
for short lengths. Of course 
Tm talking about 100 or 200 
Watts of rf, not a full gallon 
(if you want to melt coax, 
that's your business). 

The photographs show the 
completed tuner, inside and 
out, and details of the coil 
and switch S-2, as well as the 
traveling setup in and out of 
the suitcase. 

Air travelers: Be prepared 
for some delay if you carry 
the rig aboard the plane. The 
ladies who work the fluoro- 
scopes almost faint when 
they x-ray a ham radio set! ■ 



38 



Alfred F. Stahler W6AGX 
5S21 Big Oak Dr. 
San Jose CA 95129 



How to Coax Your Antenna 



Modern amateur trans- 
mitters are designed 
for a 50 Ohm unbalanced 
feedline. The classic basic 
dipoie antenna wants to be 
fed with a 73 Ohm^ balanced 



feed line. The object of this 
article is to describe the 
design of an antenna and 
feedline that simultaneously 
satisfy the requirements of 
the transmitter and the 



antenna. 

Reducing the radiation re- 
sistance of the antenna from 
73 to 50 Ohms only requires 
a reduction in antenna length. 
The literature^ 



,2,3 



on 



antenna theory is in good 
agreement and predicts a half 
length from 0,207A to 
0.231 X, depending upon 
antenna diameter and end 
conditions, A length of 








Construction of resonating coi/, ferrite tuning slugs^ and balun feed. 



40 



0.2 1 ox is recommended to 
yield a shorter antenna and a 
radiation resistance of not 
more tiian 50 Ohms. 

Reducing the antenna 
length also moves the antenna 
away from resonance and 
introduces a capacitlve reac- 
tance in series with the radia- 
tion resistance. In order to 
restore resonance in the 
shortened antenna, an induc- 
tive reactance equal to the 
antenna's capacitive reactance 
must be added in series with 
the antenna- This resonating 
inductance ts sometimes 
called a "loading coil/' The 
literature shows that the 
capacitive reactance is very 
sensitive to changes in ratio 
of antenna diameter to wave- 
length. For a 0,21 OX antenna, 
the capacitive reactance 
ranges from 34 to 230 OhmSj 
with 120 Ohms representing 
an average wire antenna. 

Fig. 1 shows a configura- 
tion of the proposed antenna: 
radiating elements cut to 
approximately 0,21 OXj two 
symmetrical variable induc- 
tors and a balanced 50 Ohm 
feedline. 

Cutting the antenna to 
length is easy^ but obtaining 
the variable inductors takes 
some care. The photo shows 
my approach to this problem. 
The inductor is made from 
B&W coil No. 3029 with two 
turns removed in the center* 
The coil is slipped over a 
John son No. 1 36-1 07 
arvtenna Insulator. A piece of 
plastic tubing, 0.75*' OD x 
0.50" ID X T\ is also 
squeezed inside the coit to 
support the two tuning slugs. 
These slugs, Amtdon 12.5 x 
100 mm ferrite rods, are used 
to tune the inductors to 
resonate the antenna. The 
range of tuning is large, from 
2.0 to 3,75 ixH for each coiL 
The coil is tapped to place 
the antenna resonance within 
the tuning range of the slugs. 
The coil and slug combina- 
tion, as shown in the photo^ 
can be used to resonate an 
antenna with a half length of 



0.21 OX for the 80 through 10 
meter bands. If the two turns 
had been left in the center of 
the coil, it would also cover 
1 60 meters. 

Tuning of the antenna is 
done at this stage, prior to 
installation of the feedline, 
by coupling a grid dip meter 
to the antenna through a 
small one turn loop soldered 
across the feed points. With 
the antenna as high as 
possible, adjust the two 



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ferrite slugs equally to 
resonance. To measure 
resonance of the antenna in 
its final position, couple the 
grid dip meter and its one 
turn coil to the antenna feed 
point by means of an open 
wire line. This line must be 
electrically Vik exactly, or 
multiples thereof, as 
measured with the grid dip 
meter; 300 Ohm twin lead is 
fine for this measurement. 
The resulting high standing 
wave ratio does not affect the 
measurement of resonandfe: 

Now that the antenna has 
been designed, built and 
resonated, the next task is 
matching its balanced 50 
Ohm impedance to the un- 
balanced 50 Ohm [mpedance 
of the transmitter. A device 
to do this is known as a 
'*balun/' a contraction for 
balanced'to-unbalanced. The 
amateur literature has 
numerous references for the 
design and construction of 
transformer- type baluns. 
These balun transformers 
have very large bandwidths 
and are particularly effective 
when used as interstage 
couplers. However, they are 
not effective for antenna 
applications unless the coax 
shield connection of the 



transformer is at true rf 
ground potential, such as the 
one described by Sevick^. 
Imagine an antenna with a 
t r a n sf %r m er- ty pe balun 
located at its feed point, This 
point Is high in the air, and 
far from rf ground. If the 
antenna is ever so slightly 
unbalanced, this wi!l be 
reflected across the trans- 
former to the coaxial feedline 
and cause antenna currents to 
flow on the outside of the 
shield; this current results in 
radiation, which couples to 
the antenna increasing the un- 
balance, which increases the 
feedline radiation, etc, etc. 
Unfortunately, this antenna 
feedline interaction is not 
self-stabilizing towards the 
balanced configuration; if it 



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CUTCENTER CC*lDUCTOR 
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AND fiEMO\fE EXCESS wrftE 




uiyBALA^^ce:D 

FEED 



Fig, 2 Schematic represehta- 
tion of 1: 1 antenna balun. 

were, there would be no need 
for a balun. 

The proposed balun design 
was first described by 
Roberts^ in 1957, but has 
not been presented in ama- 
teur publications. Fig, 2 
shows a schematic representa- 
tion of the balun; some of the 
details are visible in the 
photo. From the antenna's 
viewpoint, it is being fed by 
two equal conductors In a 
balanced feedline configura- 
tion; from the transmitter's 
side, it looks like an un- 
balanced 50 Ohm load, the 
transition taking place over 
VaK length of the balun. Note 
that this balun is ground inde- 
pendent and that radiation 



interaction between the feed- 
line and the antenna elements 
is prevented by the equal and 
opposite current flowing in 
the two outer shield feed- 
tines. The line from the balun 
to the transmitter will be 
electrically flat and can be 
any length. The reader can 
use reference 5 for the 
theory, construction details, 
and measured performance of 
this balun. 

This article has described 
the design of a dipole antenna 
and balun that matches an 
unbalanced 50 Ohm line. The 
design procedure is valid for 
parasitic arrays as well as the 
simple dipole. The perfor- 
mance of the antenna-balun 
combination has been found 
to be very good, and it 
behaves very close to theory. 
I will not describe perfor- 
mance by means of the con- 
ventional swr vs. frequency 
plot because without very 
detailed and accurate descrip- 
tions of the test antenna 
(length of feedline, loss 
characteristics of feedline, 
conductivity and diameter of 
antenna, harmonic content of 
test signal, accuracy of swr 
meter, etc.) these curves have 
little value. 

The builders of this 
antenna and/or Its balun will 
enjoy: 

• quick and easy tuning to 
resonance 

• low suT at resonance 

• minimum feedline radiation 

• improved radiation patterns 
(F to B, gain, and direction) 

• reduced harmonic radiation 

• ground independence ■ 



References 

1. R. King, C, W. Harrison, 'The 
Impedance of Short, Long and 
Capacitively Loaded Antennas 
with a Critical Discussion of the 
Antenna Problem/' Journal of 
Applied Physics, Vol. 5, 1944. 

2. Jasik, Henry, Antenna 
Engmeerfng Handbook^ McG raw- 
Hill, 1961. 

3. Shelkunoff, Sergi, Antennas; 
Theory and Practice, VWiley. 1952. 

4. Sevick, Jerry, ^'The W2FMI 20 
Meter Vertical Beam/' QST, June 
197Z 

5. Roberts, Willmar, "A New 
Wideband Balun/' Proc. i,R,E,, 
Dec. 1957, pp 1628-1631. 



41 



John Skubick K8ANG 
I 040 Meadow brook 
Warren OH 44434 





City Style 



Until recently, I thought 
that vertical antennas 
approached the ideal for 
forty meter DX contacts^ in 
terms of signal strength and 
reasonably low costs. This 

judgment was based upon 
the usual city lot antennas, 
combined with a typical 
ham's budget, The experi- 
ments of Dave WA8TN0 



proved otherwise. Let me 
first briefly describe these. 

Dave's property consists of 
two and one half acres. The 
surrounding land h flat, 
almost treeless, only a few 
well-spaced houses. His verti- 
cals consisted of two well- 
matched, quarter wave ele- 
ments made from aluminum 




BOTH APEXES JNSULATED FROM THE 
^^^MAST AND EACH OTHER 



INSULATOR 



GUYING TO GROUND 
STAKES 



/ FEEDPOJNTS LOCATED AT ^ 
/ EXACT CENTER OF BOTTOM 
/ StDES 



F/g. L 40m DX ir /angle antenna system. Each side = 45,5 ft. 
Total length of each triangle Is subject to trimming for lowswr 
at 7/100 MHz. Elements are #12 copper wire. 



downspouting. Both etennents 
were spaced one half wave- 
Jen gth apart for forty meters, 
with 180 degree (broadside) 
phasing. Each vertical ele- 
ment had 120 quarter wave 
insulated radials lying on the 
ground and equally spaced 
around. The earth in this part 
of northeastern Ohio is 
'^usually moist/' and consists 
of a loam and clay mixture. I 
believe that these are fairly 
good conditions For a land- 
based vertical system. It 
worked very well. 

The single triangle element 
consisted of small gauge wire, 
with a total length of about 
one wavelength. The apex 
was supported at the 55 ft. 
level on an existing meta! 
tower. Both low^r corners 
went to ground stakes, and 
the bouom side was about 1 2 
ft. high over the earth. This 
was fed directly, without a 
balun, with coax. The 
triangle's broadside 
** pointed'' in the same direc- 
tions as that of the vertical 
broadside array. 

This hastily-erected tri- 
angle element had much 
lower noise pickup, and gave 



stronger signal reports rriost 
of the time. Working Asia and 
Australia became a regular 
routine. In a word, the 
triangle was superior. 

City Lot DX Version 

Naturally, this old vertical 
(over wanted to try this on a 
50 ft, wide city lot, virtually 
surrounded by power and 
phone lines, high trees and 
aluminum'Sided houses in all 
directions. I ended up with 
Figs. 1 and 2, after the cori* 
elusion of my own testing 
that used my (then) existing 
half wave vertical for a com- 
parison, 

1 wanted some control 
over switching directions and 
nulls. My switching scheme in 
Fig. 2 is not original, but it 
works well. I used a Kurman^ 
double-polCj double-throw rf 
relay with a 12 V dc coil. 
Surplus rf relays are fine if 
you can find them. The .01 
uF ceramic capacitor across 
the relay coil is for stray rf 
protection. The relay is 
mounted in a black plastic 
''electronics'* box from Radio 
Shack, and bracketed IQ the 
mast aboue the feed point, Alt 



42 



{ 



TO CORRESPONDING CONNECTIONS 
AT ANTENNAS' FEEDPOINTS 



DPDT RF RELAY 




COPPER BRAJD ATTACHED 
NEAR BALUN, TO COAX 
SHIELD 




l:i 
FERRITE 
BALUN 



ir 



CERAMIC 




REMOTE DIRECTION 
CONTROL WIRES TO 

SHACK. 



RG-8A. FOAM 
COAX ANY 
LENGTH 



INSULATED RADIAL SYSTEM, 
BURIED ONE INCH(2-54CM) DIRECTLY 

UNDER ANTENNA; 8 RADJALS, EACH 
35 FT, (I0.67M) LONG. 

Fig. 2 Direction switching and feed systems. 



connecting and control leads 
are routed through the box's 
bottom to keep out rain. Try 
Lo keep the two sections of 
feeder between the antennas 
and reiay contacts reasonably 
short. Most important, rfiake 
sure these same short sections 
are the same lengths and 



spacings to keep the swr con- 
stant. 

The radials are not an 

absolute necessity. This 
antenna system worked well 
without them* However, with 
the radials the DX stations 
seem to be stronger more 
often. The 1:1 ferrite balun 



broadened the response, with 
very low swr out to the band 
edges. 

I used #1 2 gauge enameled 
hard-drawn "antenna** wire 
for the antenna elements to 
help keep down theoveralt rf 
losses. Radiation resistance 
will do you more good than 
oh mic resistance! 

Suggested apex supports 
can be an existing tower or 
tree. I used a 50 ft, tele- 
scoping TV mast. The actual 
extended height Is 48 ft.^ 
with the insulated apexes 
attached near the top. 
Bottom heighf tfS ft. 

Results 

DXing from a city lot on 
40 meters has finally become 
a real pleasure for me. Much 
of it has been easily worked. 
Getting through pileups is 
normal when running against 
the ordinary antennas 
encountered on this band. 
Perhaps the most pleasing 
aspect is getting comparable 
or sometimes better signal 



reports than some of the 
fellows using beams! My rig is 
solely an FT-101 with no 
high power attachments. 

Conclusion 

City lot dwellers, Jet^s take 
down those ordinary urban 
antennas, and quit being 
*' trapped" in our thinking. 
Now is the time to put up a 
reaJ antenna. You too can 
have a respectable 40 meter 
signal, as well as some of our 
country cousins — and with a 
lot iess grass to mow than 
they havel ■ 



References 

1. E. Noll W3FQJ, /3 Vertical, 
Beam and Triangle Antennas, 
Editors and Engine-ers, Ltd., New 
Augusta, Indiana, pp. 126-144. 
Z E: Noll W3FQJ, ^'Circuits and 
Techniques/' Ham Racfio^ August 
1971, page 56. 

3, Kurnnan Instruments Corp. 
DPDT, 12 volts dc coil, rf relay, 
model 252a Lafayette Radio 
Elecirortics Corp., 111 Jericho 
Turnpike, Syosset NY 11791. 
Stock no. 30-22183; S7.95 plus S 
ounces postage. 



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43 



73 Magazine Staff 



The Secret 2m Mobile 

Antenna 



It may be difficutt to 
accept, but there are 
many amateurs who are not 
interested in repeater opera- 
tion. But, almost all amateurs 
recognize the unique com- 
munications capability that 2 
meter repeater usage can pro- 
vide, especially in the case of 
some emergency while 
mobile. This article describes 
a matching/ isolation network 
that will allow one to use a 
regular auto antenna on 2 
meters without interfering 
with the normal operation of 
the auto's AM or AM/FM 
radio. No relays or other type 
of switching is involved. One 
can leave the network con- 
nected to a 2 meter trans- 
ceiver installed in the car or 
just bring it out to a BNC 
jack installed in the car. Then 
when a portable transceiver is 
used in the car^ it can be 
plugged into the antenna 
system. 

The performance of an 
auto antenna along with the 
matching/isolation network 
will normally not equal that 
of a rooftop VaX whip or 
similar antenna. But, no holes 
have to be drilled, extra 
antenna mounted, etc. The 
losses involved will vary from 
situation to situation, but 
should be low enough so ade- 
quate communication can be 
achieved over a local repeater 
with a few Watts of output 
power. 



LI 3I/2T 



*NT @ *■ 



^l 



C2 



3 l/2t 



# 



« - * 



3 li/BT 



^ 



■€) 



ftADIO 



r 



fig, L Matching /isolation network. All capacitors are 27 pF 
trimmers. Coifs are approximatety %'' diam.y Vi' long^ of #16 
or #J8 wire with turns as indicated. 



What is needed in a match- 
ing/isolation device is a 
matching network between 
the transmitter and antenna 
which will match impedances 
and also simultaneously act as 
a high-pass filter. Also, what 
is needed between the 
antenna and the auto radio is 
a filter to attenuate 2 meter 
energy only from getting into 
the radio. Both these func- 
tions are accomplished by the 
circuit of Fig. 1. The T 
network of Cl^ C2 and LI 
performs matching and acts 
as a high-pass filter. The rest 
of the components act as a 
rejection filter tuned to the 2 
meter transmitting frequency. 
They can be viewed as 
individual tuned circuits — 2 
parallel resonant and one 
series resonant. 

The entire network should 
be placed in a shielded 
enclosure and as close to the 



base of the auto antenna as 
possible. But, it will also 
work if placed at the end of 
the auto radio's transmission 
line (at the auto radio's 
antenna input jack), but with 
greater losses, of course. 
Wherever it is placed, how- 
ever, the auto antenna's 
extended length and the 
length of transmission line 
used to reach the antenna 
should remain unchanged 
after the network is tuned. 
Auto antenna lengths which 
produce low base feed point 
impedances are best, such as 
%\ (20/4") or 5/8X (50%"), 
but other lengths can be used. 
A length greater than 5OI/2'' 
should not be used since high 
angle radiation will increase 
sharply. 

One can either crudely 
tune the network up and let 
it go (if communication can 
be established) or attempt to 
tune it up for overall 



minimum losses. In any case, 
a bench check should first be 
made with a grid-dip meter. 
Short all the input/output 
points. Then resonate the CI, 
C2j LI circuit (by coupling to 
LI) for resonance about 2 
MHz below the transmitting 
frequency. After installing 
the network in its operating 
location, re-adjust CI and C2 
for maximum Field strength 
reading. 

If you want to tune up the 
whole network more 
properly, an swr meter has to 
be inserted in the trans- 
mission line to the auto 
antenna. Leave the output 
terminal to the auto receiver 
connected. Adjust CI , C2 and 
L1^ if necessary, for the 
lowest swr. With an odd 
length of transmission line, it 
might even be necessary to 
add some inductance in series 
with C2 for lowest swr. Then 
connect the swr meter in the 
line to the autp, receiver and, 
using only the "forward" or 
'*set" reading, adjust the trap 
trimmers for a minimum 
reading. One then has to go 
back and Forth several times 
with the swr meter in each 
line to compensate for the 
detuning effect of each 
adjustment on the network. 

When carefully adjusted, 
one can simultaneously use 
the auto antenna for 2 meter 
communication and AM or 
FM reception. ■ 



44 



II 



I 



111 



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state-of-the-art electronics, corrosion-free fiberglass and tal<e-apart 
design for true portable use. 

The Hy-Gain 272 is an entirely self-supporting 21 ' omnidirectional 
antenna system that separates into three pieces for transport. 
It consists of 4 stacked 5/8 wave radiators with three 1/2 wave phasing 
coils and a 1/4 wave decoupling system. 

Each section length is specifically computed to completely 
eliminate end-feed pattern tilt, keeping radiation angle flat and close 
to the ground for maximum efficiency. 

The 272 is ideal for portable repeater, repeater, and home use. 
Take it with you, wherever you go. Mounts easily on any 1 - 1/4" to 
1-1/2" masts and it's factory tuned, to eliminate re-tuning in the field. 
Recessed coax connector, mounting bracket and hardware included. 

Get the first truly portable repeater antenna. Only from Hy-Gain. 

Power 250 watts 

VSWR at resonance Less than 1.5:1 
Input Impedance 50 ohms 

Produces 6 dB gain over 1/2 wave dipole 




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105ft £36 It! ) 
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Fig. h 1 60 W dual 
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An 



FEEDLINE {SEE TEXT) 



BALliN OR TUWEH 
CSEE TEXT) 



Inverted Vee 
for l60/80m 



RG-8/U ANY LENGTH 
TO TRANSMITTER 



John Skubick KSANG 
1Q4Q M&adowbrook 
Warren OH 44484 

City lots and bank 
accounts have some- 
thing in common for many of 
us. Both tend to be small! 
Here is a cheap antenna 
system that covers both 80 
and 160 meters, but is the 
size of an 80 meter 'Inverted 
V/* with no ground radials. If 
your city or suburban lot is 
typical, you'll barely have 
room for one 160 meter 
radial, let alone several! 

On 80 it is an inverted, 
folded dipole. The feedpoint 
impedance is less than 300 
Ohms because of the inverted 
shape. For 1 60 it becomes a 
half wave inverted dipole, 
with the ends folded back 
toward the middle, and *'end 
fed/' The feedpoint impe- 
dance now becomes very 
high. The flat top portion can 
be constructed from trans- 
mitting twinlead^ TV twin- 
lead, or 300 or 450 Ohm TV 
open wire. You can even 
make it out of ordinary 
'^antenna wire'* if the parallel 
wires are spaced up to 6 
inches. The length is approxi- 
mately 70 feet for each leg. 
More on leg length later. 



Since both bands utilize 
the same feedpolfit, we must 
have a simple and effective 
feeder system for both 
bands/irhpedahjces as follows: 

Without a Tuner 

Two baluns are required at 
the shack end of the feed 
line. A 4:1 for 80, and a 1:1 
for 160. 1 used two Amidon' , 
"$5,00 balun kits." I put two 
layers of plastic electrrcal 
tape over each core for better 
**arc-over" protection. Both 
baluns were easily wound 
within 30 minutes, per 
enclosed instructions. Use 36 
inches of wire for each 
winding, leaving about two 
inches extra for lead connec- 
tions. I put each balun into a 
34<^ plastic, screw-lid, freezer 
container^ with a coax socket 
attached. All possible 
openings were then gen- 
erously sealed with a tube of 
G,E. Silicone Seal, sold by 
blister-pack in most hardware 
stores. Ami don's spec sheet 
states, ''80-6 meter opera- 
tion.'' However, these baluns 
seem to work just fine on 1 60 
as wel I ! 

Use RG-8 between the 
balun(s) and the transmitter. 
The feed line between the 



balun (s) and antenna should 
be ''300 Ohms'* type such as 
twinlead, or better yet 300 
Ohm, TV, open wire 'ladder- 
line" for higher power hand- 
ling. The dimensions for the 
balun-to-antenna feed line are 
no feet for solid dielectric 
twinleads or 130 Teet for the 
open wire line. 

Initial tuneup begins with 
80 (or 75) meters, for your 
favorite section of the band, 
by trimming the ends of the 
flat top equally, a couple of 
inches at a time, for 
minimum swr (measured at 
the transmitter}. A neat 
"trick" is to trim it for "75 
phone/' then hang clip-on 
single vtfire outriggers for '*80 
CW." Minimum swr will be 
about 1.5:1, using the 4:1 
balun. Since the antenna is 
inverted and close to ground, 
the feeder is "seeing'* less 
then 300 Ohms from the 
folded dipole. 

Next is the 160 meter 
tuneup. Change over to the 
1:1 balun. Now, trim the 
twinlead (or open wire) feed 
line for minimum swr in your 
favorite portion of 1 60. You 
can get this down to 1 :1. 
That's it for "tuneriess'* oper- 
ation. 



With a Tuner (Antenna 
Coupler) 

It's easy for you tuner 
lovers. From my experiments, 
it appears that the leg length 
can vary between 60 to 70 
feet with no reduction in 
performance, for either band. 
Your coupler will "tune/* this 
antenna and feeder system 
over the entire 1 60 and 80 
meter (and 75) bands. 

You have a wider choice 
of feed lines also. You can 
use TV and transmitting twin- 
leads, 300 and 450 Ohm TV 
open wire 'ladderlines,*' or 
even home brew openwire 
line. The length of balanced 
feed line, between the 
antenna and your coupler, 
may load easier if it is about 
90 to 120 feet for the solid 
dielectric types, or 120 to 
140 feet for the open wire 
types. 

For the antenna coupler 
tuneup, first preset your 
transmitter's "tuning and 
loading'' controls, by loading 
it directly into a 50 Ohm 
dummy load, (You do have a 
dummy load, don't you?) 
Now, switch the transmitter 
into the coupler. Do not 
touch the transmitter's 
''tuning and loading'' con- 



46 



trolSjt because they are now 
preset for 50 Ohms. Do your 
tuning and loading with the 
coupler, which wifl transform 
whatever impedance and reac- 
tance is appearing at the 
**shack end'* of the feed line 
into 50 Ohms for your trans- 
mitter. If you are a tuner 
fancier, and have read this 
far^ chances are you already 
have a coupler for 80 meters 
and the higher bands. Fig. 2 
shows a compatible type of 
coupler for 160. 

Antenna Supports 

! used a 50 foot, 5 section, 
telescoping TV mast to 
support the apex. Actual 
extended height is 48 feet. 
The mast is hinged at the 
base, by driving two 3 foot x 
2 inch pipes into the ground 
about 3 inches apart, I drilled 
a hole into each pipe, so that 
a suitable large bolt could be 
passed through both pipes 
and the existing hole at the 
base of the mast. 

The antenna supports the 



mast in the east-west direc- 
tion. Two lengths of non- 
metallic clothesline also 
support the mast from the 
top, but in the north-south 
direction. No center guys 
were used. 

The insulator ends of the 
antenna^ and the ends of the 
clothesline, are attached to 5 
footx IV2 inch pipes driven 3 
feet into the ground. 

The entire assembly isn^t 
too heavy. It couldn't be, if 
skinny, strlngbean-physiqued 
K8ANG has to lift it up and 
walk it into the vertical posi- 
tion! 

A tree and a halyard can 
also be pressed into service 
for the center support. My 
trees are never properly 
located. 

Results 

it certainly gets the rf out 
of my backyard! On 80, the 
performance is exactly that 
of a "regular*' Vi wave 
inverted dipoie, using the 
same height, center 



L2 



39 TURNS 





^ 



U <\B TURNS 



CI l200pF 
39 TURNS 



C2q 
350 pF 



BALANCED 
FEEDLINE 



C2b 
350 pF 



Fig. 2. 160m antenna coupler, LI-L2: lllumnitronic 2410 or 
Polycolls 1780^ lOTjinch^ 3 Inch diam, CI: Three section 
''broadcast'' type^ all sections paralleled. C2: 200 pF per 
section may be used with 100 pF In parallel Note: Do not 
ground any portion of L2 or C2 - leave them *' floating" above 
ground on Insulators. 



supported. It also seems to be 
more broadbanded. On 160 I 
have worked coast-to-coast, 
2ir\d Canada easily, using a 
barefoot Japanese transceiver. 
I cannot compare it to a full 
size inverted dipole on 160, 
because this would be twice 
the size of my backyard! 

Conclusion 

There have been many 1 60 
and 80 meter antenna articles 
written these past few years. 
Not all of them will fit every- 
one's backyard or perfor- 
mance specifications. Maybe 



this one will help to 'Till the 
void*^ in your city lot antenna 
farm. ■ 

References 

1. Amidon Associates, 12033 
Otsego Street, North Hollywood 
CA 91607, 

2. Bonadio W2WLR, "Antenna 
Tuner fof Optimum PotA^er Trans- 
fer/' Ham Radio, May 1970, p. 
28. 

3. Greenberg W2EEJ. "The Forty 
Meter Folded Dipole and Other 
Bands/' Antenna Roundup^ 1965, 
Cowan Publishing Corp., p. 89. 

4. ARHL Antenna Book, 1968, 
pp, 206-207. 

5. Orr W6SAI, S-9 Signafs^ Radio 
Publications, Inc., p. 44. 



Switch Your Antenna Where It Really Counts 

AT THE ANTENNA 




l ii ii illiipi i imjLjttJ^^ 



-ijiWJ'N' 



I 



w 



The RELAY: 

Inline* TYPE 101 Relay can be controlled directly or remotely via the 
coaxial cable. It can be installed atop a tower or pole to switch two 
antennas without adding wires. 

Frequency capability is from V.L.F. through V,H.F. Hermetically 
sealed switching element is capable of multimillion operations assuring 
years of trouble free, dependable service. 





The COUPLER; 

Consisting of a coaxial isolator and resonator which determines the bandpass of the 
device. When DC or AC power/voltage is connected across the coupler injection port and 
ground, the signal cable acts as a metallic link without disturbing signal characteristics 
originally present. RF signal path is not directional. 

Two couplers can be used, one locally and one remotely, with the arrows pointing to 
each other. The coaxial cable between the couplers is thus multiplexed whereby the inner 
conductor and shield act as a simple wire pair while simultaneously carrying RF signals 
within the rated passband. Power/voltage may be injected or recovered at either coupler. 



INLINE INSTRUMENTS Inc 

Box 473, Hooksett, New Hampshire 03106 



TUFTS 

Radio Electronics 

?9rt PAiinSJi . IMHflnrri HA miba 



47 



Robert J. Wright PYSZAC/WSVOH 

Cajxa Postal 1 81 

66000 Bel&n, Para, Brazil 



About ten years ago, the 
Summer Institute of 
Linguistics (SIL) here in 
Brazil was granted permission 
to use radios for communica- 
tion between our centers and 
remote Indian villages. SIL is 
working here and in other 
countries with people who 
speak some of the more than 
2000 unwritten languages of 
the world. Our purpose is to 
learn these languages, analyze 
them, teach the people to 
read and write their own 
language, and translate the 
New Testament for them. 
Here in Brazil, the linguistic- 
translation teams live in the 
Indian villages for periods of 
from about three to six 
months at a time, takirtg a 
radio with them each time to 
maintain contact with one of 
our five centers. We arc 
using the Stoner SSB-20A 
radio, an excellent portable 
with about 15 Watts PEP 
output, powered by any 12 
volt Source including dry 
cells. The antennas are 
dipales about 86 feet long. 
Co m m u n i cations d istances 
range from about 100 miles 
to over 500 miles. 

Because of the importance 
of the radio communications 
and because the equipment 
has to be set up and taken 
down each time by non- 
technical personnel, one area 
of potential problems was the 



The 



Dipole 



Dangler 



antenna system. The antennas 
had to be reliable, rugged, 
and easily handled. Because 
more than 40 stations were 
involved, they also had to be 
inexpensive and made fronh 
readily available materials. 
The purpose of this article is 
to share some of our 
experience with you with the 
hope that some of the ideas 
might prove useful to you for 
your home station antennas, 
or for portable antennas for 



ADJUST TO FIT 

fNSULATOR 
SIZE 




9/64 DRfLL 
4 HOLES 



MO. IB WIRE 



|/4"DIA 
3 HOLES 



field day use, etc. 

The construction of the 
center insulator is a very 
important factor in building a 
reliable dipole antenna. Pur- 
chasing a commercial unit 
was not practical for us 
because of cost and also the 
delay in obtaining it- The 
center insulator we have been 
using consists of a standard 
porcelain insulator to which 
is attached a piece of Ya inch 
plastic in the form of a cross. 




1/4" 6m(n(APPR0X) 



Fig. h Center insulator. 



See Fig. 1 , The porcelain 
insulator provides the 
necessary strength, and the 
plastic gives support to the 
coax cable. The plastic is 
attached to the insulator with 
No. 18 solid copper wire, 
wrapped twice around the 
insulator and twisted together 
in back of the plastic. Three 
holes are drilled in the plastic 
to support the coax cable. 

We have been using 
flexible, bare-copper antenna 
wire, and this has proved very 
adequate. To attach the wire 
to the center insulator, pass 
the wire through the hole 
twice and wrap the end 
around snugly for a distance 
of at least three inches. 
Attach both legs to the center 
insulator and attach the end 
insulators in the same way. 
Do not solder anything at this 
time. Before going any 
further, wrap the antenna legs 
on wooden forms as 
described below. This makes 
a neat package to take into 
the shop to attach the coax 
cable. 

Cut the coax cable to 
length, unless you want to 
wait and install the antenna 
first. Pass the end of the cable 
through the holes in the 
plastiCj starting from the back 
as shown in Fig, Z Remove 
about 12 inches of the plastic 
jacket. Remove the center 
conductor from the braid by 
pulling it through the braid. 
Do not comb out the braid. 

Use standard vinyl tape 
cut to about 3/8 inch in 
width to seal the point where 
the center conductor leaves 
the braid. Seal this junction 
very carefully. After the 
antenna is completed, we also 
seal this further with Q-dope 
or epoxy cement to make it 
as watertight as possible* 

Pass each of the con- 
ductors {center conductor 
and braid) through one of the 
holes in the center insulator, 
drawing the braid side tighter 
than the other so that it will 
take the strain. Pass the braid 
through a second time and 
wrap it over the antenna wire, 



48 



THIS AREA SEALED 
WITH TAPE AMD EPOXY 



INSULATION OIN 
CENTER CONDUCTOR 




TAPE 

THIS 

AREA 




Fig. 2 



in the same direction as the 
original wrapping. Solder the 
braid to the wire in the 
middle of the wr dipping, 
leaving the rest free to flex. 
Pass the center conductor 
through the hole a second 
time and lay it alongside the 
wrapping on the antenna 
wire. Mark a half way pomt 
on the wrapping and strip the 
insulation lo this point only. 
I have found it very easy to 
strip the insulation from coax 
by scoring the insulation with 
wire strippers every Va inch or 
so and then crushing the insu- 
lation with long nose pliers to 
break the adhesion between it 
and the wire. After ihis^ the 
insulation comes off rela- 
tively easily. Once the wire is 
stripped, wrap it around the 



antenna wire a few turns. Do 
not tin the wire if it is 
stranded. Solder the center 
conductor lo the antenna 
wire, making sure that ihe 
antenna can be pulled straight 
without straining the coax 
inner conductor. Solder only 
where the conductor attaches 
to the antenna wire. Rein- 
force the entire connection 
by wrapping vinyl tape 
securely around both the 
inner conductor and the 
antenna wire, starting from 
the center insulator and 
extending past the solder 
joint. This is very imporiani 
because it secures the center 
conductor to the antenna leg, 
allowing a minimum of inde* 
pendent movement and 
reducing the threat of 



breakage at what is probably 
the most fragile part of the 
whole antenna. Tape the coax 
cable to thfc plastic support 
between the lower two holes. 

At this point, seal the ''V*' 
in the coax with epoxy 
cement or other seater and let 
it dry. Install the coax plug 
and the antenna is ready for 
use. 

After the antenna is con- 
structed, care in handling is 
very important to long life 
(for the antenna). Many of 
you know the frustrating 
tangle that you can have with 
a long dipole antenna that has 
been coiled up and then 
uncoiled improperly. To 
avoid this J we are using 
wooden forms made from 14 
inch plywood cut to approxi- 
mately 5 by 7 inches. Each 
leg of the antenna is carefully 
wound on one of these forms 
to avoid tangling. To use the 
form, extend the antenna out 
full length on the ground and 
carefully check it for kinks. 
Starting at the end of one leg, 
carefully wind the antenna on 
the form by winding the form 
onto ihe wire while walking 
toward the center insulator- 
Do not coil the wire onto the 
form. Use one form for each 
leg. When you get ready to 
rc-in stall the antenna, care- 
fully unwind the wooden 
forms, leaving the antenna 
fully extended on the ground. 
Do not pull the wire from the 
forms or you will have a 
kinky mess. Carefully check 
for kfnks or other problems 
before installing the antenna. 



FKAHK 



WB6LDN 



:Fiiyriii:tU:>iri^iiifcifilJ 



AMATEUR_ RAOia 

■q cuufomm 

WB6ZCT 



LOS imatLE 



DIE CAST CHROME LrCENSE FRAME 

Your WAME. QTK, 73 etc, in vinyJ ieiiers {umx. 121 

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fi-iiieter^ thru 4Sd MHz. Hea^y capper construct tan. 
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your repeater's pftrfflrmanci. Wrfte ar call tod.Tv ' 

Varden Electronici Company 

mo* 791. JjKkion. MlthlgBii 49204 ■ latTlTVTia*^ 



Multiple frequency 
antennas can be made using a 
modified center insulator as 
^hown in Fig, 3. Spacers for 
separating the antenna legs 
can be made from 3/8 inch 
plastic electrical conduit, or 
the second antenna can be in 
the form of an inverted V. In 
this case, the antenna will 
need to be five per cent 
longer than a normal dipole. 

Using this method of con- 
struction and using the 
wooden forms for handling 
the antennas, we have had a 
minimum number of 
problems with our antennas 
during these past years. ■ 



O 







C2IJ0) 



© 








USE AS MANY IIVSULATOAS 
AS REQUIREO 

Fig, 3, Center insulator for 

multiple frequency dipole. 



BYTE ISSUES rfl ^ #3 #4 

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49 




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VS^e'll send you a beauty... 



This beautiful Walkie-Talkie Kit is easy to build and can be assembled in one weekend. You save 
hundreds of dollars by building it yourself. The HT-144B offers exceptional performance at a 
budget price. 



2 Walts minimum 
4 Channels 

35uV for 20dB of quieting 
Low battery drain - . . less than 10 Ma 
Now you can build a commercial quality 
walkie talkie at home at half the price. 
Designed with the ham m mind. Average 
assembly time^ just 10 hours. 
Small and handy, yet targe enough to be 
assembled wtth conventional tools. 
Attractive, scratch resistant textured finish. 
Lightweight J sturdy afuminum case- 
Black textured case 1-1/2 x 2-1/2 x 9-1/4 
All tunable colls are prewound 
Transceiver is on one G-10 predrilled board 



• Parts layout silk-screened on boards for 
easy construction 

•Crystal deck h separate predrilled board 

• Weight less batteries — approximately 15 
oz. 

• Battery-case is A A size - accepts alkaline 
or nicad 

• External battery charging/ power supply 
jack furnished 

• 1 dual gate mosfet 2 LC.'s 15 transistors 7 
diodes 

• Antenna — collapsible 17'* whip 

• Covers any 2 Mhz segment between 140 
and 170 Mhz 

• Plenty of room in case for add ons (PL 
and tone) 



HT-144B RECEIVER SPECIFICATIONS: SENSITIVITY better than .3SuV for 20db 
quieting, SQUELCH THRESHOLD belter than .25uV, STABILITY .002 typical (depends 
on crystal). ADJACENT CHANNEL REJECTION 60 db, SPURIOUS RESPONSES down 
70db. FIRST IF 10.7 Mh? SECOND IF 455 Khz. FILTER 4 pole monolithic 10.7 Mhz 
crysial. DISCRIMINATOR pretuned ceramic 455 Khz. BANDWIDTH 15 Khz at 3db 
points. CRYSTAL 45 Mhz parallel at 20pf. CRYSTAL FORMULA receive frequency minus 
10.7 divided by 3. AUDIO OUTPUT .5w lypicaL CURRENT DRAIN 10 ma squelched, 
100 ma on voice peaks, 

HT^144B TRANSMITTER SPECIFICATIONS: OUTPUT 2 watts minimum, 3 DB BAND- 
WIDTH 2 Mhz typicaL STABILITY .002 typical (depends on crystal). SPURIOUS outputs 
down 30db or better. MODULATION true FM with varactor in crystal circuit. NETTING 
separate trimmers for each channel, DEVIATION adjustable to 7 Khz. AUDIO Mm iter and 
active low pass filter. MICROPHONE speaker type. CRYSTAL IS Mhz parallel at 20 pf. 
MULTIPLICATION FACTOR frequency times 8. CURRENT DRAIN 500 ma typical. 

LIMITED OFFER 
Now an even better buy . , , 

$129,95 includes Walkie Talkie Kit, 1 set of crystals for 146,52 
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with purchase of $29.95 Vi amp N ICAD Pack. 





ORDER FORM 






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*Wilh purehdic ijf HT-I4JG Wdlkii? Tjlkic •*Wiifi (H^rd^-isv v.\ HT-I44B Wdlkic fjlkic jfiJ NICAD B^lEncy 
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SmPPtlSst; INFORMATION: 
All >ilii|)ii)(!ni!^ jrt K.O.B. Bint- 

1 1.1 rn tun, N.V. 13902, Shtp- 
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RETURNS: Obtain duKhofi/a- 

tiorr (rom VHF- before rftlum: 

ir^i any tncrthan-Jtsc, 

PRICES AND SPECJFICA 

I IONS: Subi«(,1 U* (.hAnfic 

wilhuut riylitil, 

Eflpcjri prieEi-i in: ftiishily 

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OIVlSiQN OF BROWNfAh! ElECTHQNtCS CORK 

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# engineertns 

MINI -CATALOG 1976 

THE WORLD'S MOST COMPLETE LINE 

OF 
VHF - FM KITS AND EQUIPMENT 



TX144B Kit. 
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TX432B Kit, 
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RX50C Kit 



RX144CKit 



RX144C W/T 



RX220C . 



RX432CKtt 



RXCF. , 



transmitter exciter — 1 watt — 

2 meters , $ 29,95 

same as above —factory wired 

and tested 49.95 

transmitter exciter — 1 watt — 

220 MHz , 29JS 

same as above —factory wired 

and tested 49,95 

transmitter exciter 432 MHz .., 39,95 

same as above — factory wired 

and tested , 59.95 

30-60 MHz rcvr w/2 pole 10,7 

MHz crystal fitter 59,95 

140-170 MHz rcvr w/2 pole 10.7 

MHz crystal filter .,, , 69.95 

same as above — factory wired 

and tested . . , 114,95 

210-240 MHz rcvr w/2 pole 10.7 

MHz crystal filter . 69,95 

432 MHz rcvr w/2 pole 1 0,7 MHz 

crystal filter .,.,.,.,.... 79,95 

accessory filter for above receiver 

kits gives 70DB adjacent channel 

rejection .............. B,50 

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case, connectors ..,,»,♦... 59,95 

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2 meter power amp — 1w in — 
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similar to PAT 44/15 kit except 

25w QUI 49,95 

similar to PA1 44/1 5 for 220 MHz 39.95 

power amp — similar to PA144/1 5 

except I Ow and 432 MHz .... 49.95 

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amp ^ factory wired and tested . 179.95 

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amp ~ factory wired and tested , 159.95 



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current limitmg and overvoltage 
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current limiting and overvoltage 

protection . . . 129.95 

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RPT144Kit . . 


repeater — 2 meter — 15w — 






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repeater - 220 MHz - 15w - 






complete {(ess crystals) ...... 


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RPT432 Kit . . 


repeater - 10 watt - 432 MHz 






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S\S.9S 


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repeater - 15 watt — 2 meter — 






factory wired and tested 


695.95 


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repeater - 15 watt - 220 MHz - 






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749,95 



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CD1 Kit . 
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complete COR with 3 second and 

3 minute timers ............. 19,95 

10 channel au toucan adapter for RX 
we stock most repeater & simplex 
pairs from 146.0-147,0 (each) 



. . i 4 



Hatph i; Tiiggan WBSDQT 
4SI5 Oakwood Drive 
Okemas MI 48864 



Amateur Weather 

Reception 




One of the euphemisms that is often 
used to describe the limes in which we 
live is the "space age." The gradual buildup 
of technology that enables mankind to li^vel 
and work in space and to visit other worlds 
has resulted in a whole new age of explora- 
tion as we gradually learn more about the 
larger universe in which we live. Probably no 
aspect of the space program has a greater 
effect 00 our lives than the tremendous 
strides in weather satellite technology. To 
many, such satellites are merely the "eyes in 
the sky'* that serve to amplify the v^ather 
map on late night news, but ihey are far 
more important than that- They have con- 
tributed to new standards in Vi^eather fore- 
casting and provide an early warning system 
that has saved uncounted lives and dollars by 
providing advanced warning of destructive 
tropica! storms such as typhoons, cyclones, 



and hurricanes. Mapping of snow and ice 

cover is still another spin*off from this useful 
program. At the time this article is being 
written there arc seven operational U.S* 
weather satellites in orbit around our planet 
continuously scanning the ever-changing 
weather patterns thai affect our lives. 

It is now a decade since Wendel Anderson 
K2RNF first showed how it was possible to 
receive and display pictures from such 
satellites (2) and with today *s technology 
the job is far easier than it was just ten years 
ago. With far less financial outlay than that 
required for even a modest sideband station 
it is possible for amateurs to receive and 
display pictures from most of the opera- 
tional satellites^ while for someone who is 
really hung up on the subject none of them 
is out of reach. The purpose of this article 





APT Mode 


SR Mode 


Subcarfter Frequency 


2400 Hz 


2400 H; 


Subc^rrter Amplitude: 






White 


Maximum 


Mas^imum 


Slack 


Minimum 


Minimum 


Lin« Rate 


240 /minute 


4fi/mlnute 1 present) 
120 /minute (future!^ 


Frame Time 


2O0 seconds 


Continuous 


Un^* Per Picture 


&O0 


Depends on ler^K of pass 


Video Bar^diAfidth 


1600 kHz 


450 Hz (IR) 




i 


900 Hi (visible) 



Tabk h Chafuctenstics of the video formal of the APT&nd SR modes. 



Nome 


Frequency (MHz) 


Period 


Inclination 


Mode 


Products 


ESS A 8 


137.62 


114 J min 


101,5'* 


APT 


Daylight real-time cloud 
cover pictures 


N0AA3 


137.5 (primary) 
137.62 (test) 


116. min 


102° 


SR 


Visible and infrared cloud 
cover pictures m daylight, 
IR cloud cover pictures at 
night 


NOAA 4 


Same as NO AA 3 


IIB.Omin 


101.7*" 


SR 


Same as NOAA 3 



Table 2. Polar orbitmg weather satellites. 



will be to describe the status of the various 
satellite systems now in use and to provide 
numerous references for the construction of 
home sateiliie receiving stations. Such 
stations cart provide daily glimpses of the 
world from space which few of us would 
ever see and are an interesting entry into the 
world of meteorology. The low cost of such 
ground stations make them attractive to 
small educational institutions where they 
can provide practical data for courses in 
weather and the earth and planetary sciences 
as wetl as providing worthwhile class projects 
in electronics. 

There is certainly no "one way'* to put 
together a satellite station — there are a 
multitude of options, each varying in terms 
of cost, operating ease, and system flexi- 
bility. I will discuss the various requirements 
for satellite ground stations and provide 
references from the widely scattered liter* 
alure on the subject so that you can do some 
background reading on the kind of system 
yoy might like to set up. Some of the 
options are essentially jury-riggied affairs of 
casual interest but others can, at low cost, 
provide performance comparable to com- 
mercial or government installations. Ever 
stfKe entering the weather satellite game 
amateurs have distinguished themselves by 
continually developing better ways to 
accomplish various tasks, usually far 
exceeding professionals in terms of the 
cosl-quality equation. Amateurs, with their 
knowledge of electronic and communica- 
tions systems, are often among the first to 
spot problems with operating satellite 
systems and thus provide a valuable service 
in monitoring these satellites. Weather 
satellite technology represents a very con- 
crete example of how ''amateurs" can make 
a significant contribution to space age tech- 
nology. Why not give it serious thought — 
you are certain to have lots of fun and may 



S2 



make some major contrtbyiiom ^t the same 
time! 

Satellite Picture Modes, The two video 
modes of greatest inieresi lo amateurs arc 
highlighted in Table L Both modes utilize a 
24O0 Hz aLidio subcarrier to transmit the 
video information. Subcarrier amplitude 
varies from maximum for while picture areas 
to minimum (approximately 4% of 
maximum ampNlude) for b!ack picture 
areas. Subcarrier amplitudes between these 
two extremes represent varying shades of 
gray. The two modes differ however in the 
line rate and ptcture organization. The first, 
the APT mode (APT is an acronym for 
/Automatic Picture Transmission), transmits 
video lines at the rate of 240 per minute or 4 
lines per second. A single picture or **frame'^ 
requires 200 seconds for transmission^ 
resuhing in an SCO line picture. The base- 
band video bandwidth of the system is 1600 



kHz, so if audio fillers are used lo help 
remove noise from the satellite signal they 
should be centered on 2400 Hz with a 1600 
Hz bandwidth. Narrower filters will result in 
progressive loss of picture detail. The 800 
line APT picture is far sharper and has much 
greater resolution than a typical TV picture 
display. 

The second mode — the SR or Scanning 
/? ad io meter mode - is based on the use of a 
mechanical scanning system on board the 
spacecraft. As the satellite moves along its 
orbital track a mirror scans the earth 
beneath in a narrow beam at right angles to 
the satellite's orbtta! track. Present SR 
systems use a 48 line per minute scanner. 
The SR system is capable of providing both 
visible light and infrared (IR) images of the 
earth below. The IR data occupies the first 
half of the scanning line wiih the visible data 
inserted from a tape loop during the second 



half of the line when the satellite scanner is 
scanning up against the spacecraft. The SR 
data format can be considered as a 4S line 
per minute system with half the line being 
IR data and the other half visible dau, or it 
can be treated as a 96 line per minute system 
of alternating IR and visible data fines. 
Display systems can be designed around 
either option. The SR picture is not broken 
up into discrete frames as it is in the APT 
mode — instead transmission of picture data 
is continuous as long as the spacecraft is \n 
range with the vertical **scanning" provided 
by the movement of the spacecraft along its 
orbital track. Present systems utilize a 48 
line per minute scanner but in 1978 a new 
SR system utiii/tng a 120 rpm scanner will 
be inaugurated. The principles of operation 
are idemlcal to the 48 line system except 
that the pictures will be several limes better 
in resolution. Various display systems for 48 




Photo 1. Visible fight (left) and infrared (right) readout from a single NOAA 4 pass over eastern 
North America on 20 November 1975. The differences in the two views^ which represent the 
same area as seen at the same time^ are due to the characteristics of the visible and IR Imaging 
systems. The visible channel sensors respond lo fight In much the same manner as the human 
eye^ and all cloud structures are shown where sufficient light exists. The upper right portion of 
the visible view (northwest) Is dark because of low sun angle at high northern latitudes at this 
season and time of day (early morning). The IR channel responds to heal, w'nh I he lightest 
areas representing cold zones and with darker areas progressively warmer. Low clouds do not 
appear fas they are near ground temperature), while the At fan tic (fower right) appears darker 
than the fand areas lo the west because the ocean waters are warmer than the ground at this 
season of the yean 



53 




Photo 2. An example of an APT WEFAX transmission from ATS 3. Such 
computer gridded pictures are put together on the ground from NO A A SR 
data and are relayed through the geostationary satellite for worldwide 
distribution to any staiion within line of sight of the sale! lite. The yiew 
shown here represents % of a polar projection of the southern hemisphere 
showing most of South America and part of Antarctica, In this case the 
picture was put together by computer analysis of NOAA IR readout. Grid 
tines were superimposed and the picture was then relayed through the 
satellite. 



line SR service can be modified for 120 line 
display with comparatively little dfffrculty. 
Baseband video bandwidth for the IR 
"channel" of the 48 line SR system is 450 
Hz while the visible channel bandwidth is 
900 Hz. Ai with the APT mode, if 2400 Hz 
audio filters are used they should have a 
bandwidth at least equal to that of the 
channel in use to get full picture resolution. 

Operational Satellite Systems. There are 
two general. types of satellite systems of 
potential use to amateurs — polar orbiting 
satellites and geostationary satellites. Each 
will be discussed separately. 

Polar Orbiting Satellites. Polar orbiting 
satellrteSj actually in near polar orbits, 
provide continuous real-time transmission of 
cloud cover pictures on a worldwide basis. 
Table 2 summarizes the data on operational 
polar orbiting satellites. Each of these 
satellites provides either 2 or 3 useful day- 
light passes per day within range of a given 
ground station, and an equal number of night 
passes. All of the systems provide useful 
daylight coverage and some provide night 



pictures as well, ESSA S, launched in (ate 
1968, IS the oldest of the operational polar 
orbiting spacecraft and is the last of its 
series. Using a TV camera tube and trans- 
mitting APT pictures on 137.62 MHz, this 
satellite provides as many as three useful 
pictures on a single pass during daylight 



Name 
ATS1 



Frequency (MHz^ 
135.6 



Subpoint 



o 



149 W 



ATS 3 



135.6 



sg^'w 



SMS 1 



1691 



75** W 



SMS 2 



1691 



11 b"^ W 



hours. The spacecraft h solar powered and is 
shut down on night sides of its orbit where 
the TV camera is non-functional. Early in 
1975 the performance of camera #1 
dropped past the useful level and <;amera #2 
was switched on to replace ft. Late that year 
the camera shutter on the spacecraft began 
to malfunction — a prelude to total system 
failure in earlier satellites in the ESgA series, 
Jt is probable that this particular satellite 
may well be shut down by the time this 
article appears in print and no future 
satellites of the series are plar^ned. 

The primary polar orbiting satellite series 
now in use and planned for use well into the 
1980s is the NOAA satellite series, of which 
NOAA 3 and 4, operational at the time this 
is written, are prime examples. These 
satellites transmit SR pictures at a frequency 
of 137.5 MHz with monthly one-day tests at 
137.62 MHz. Their orbits are essentially 
identical to that of ESSA and are chosen so 
that the satellite passes over a given location 
at about the same time every day. The SR 
systems aboard these spacecraft provide 
both visible and IR cloud cover pictures 
during daylight passes and IR pictures during 
evening passes. Photo 1 shows an example of 
both visible and IR data from a single pass. 
The data display is in the form of a 
continuous strip of picture material that is 
received as long as the spacecraft is above 
the horizon. The examples shown represent 
about 10 minutes of coverage from the pass 
in question. Such satellites are ideal for 
obtaining localized weather patterns, for it is 
possible to gel a direct overhead view of 
local weather systems and for a single pass 
the weather pattern for about half of the 
North American continent — in a strip 
extending from Greenland to Yucatan - can 
be obtained for a station located In the 
north-central U,S. NOAA 4 is currently the 
primary spacecraft in the series with NOAA 
3 serving as a backup. If the orbit of NOAA 
3 brings it in conflict with NOAA 4, 3 is 
switched to 137.62 MHz. NOAA 5 is 
scheduled for launch in early 1976^ at which 
point NOAA 3 will be deactivated and 
NOAA 4 will serve as the backup spacecraft 
if all goes well. 



Mode 
APT 



APT 



APT 



APT 



Products 

WEFAX — Sateljjte predict messages, 
grey scale, computer giiddeci 
cloud cover pictures from 
MOAA dgta (wG$tern U.S., 
Pacific, E. Asia, E, Africa) 

WEFAX - Similar to ATS 1 esccept 
coverage centers on eastern 
U.S., Atlantic, Europe, West 
Africa, South America 

WEFAX - Computer gridded visible 
and IR views derfved from 
on board spin scan very high 
resolution radiometer, 
pictures sectorized from 
fulf earth disc 

WEFAX - Similar to SMS 1 



Table 3. Geostationary satellites transmitting weather picture data. 



54 



Geostationary Satdllte Systems. Geosta- 
tionary satellites are satellites whose orbital 
path lies over the equator. The altitude of 
the satellite is approximately 22,000 miles 
so its orbital period is exactly 24 hours. 
Since the satellite orbitaJ period is equal to 
the period of rotation of the earth the 
satellite always maintains the same position 
over the equator. This position is known as 
the satellite subpofnt. Since such a satellite 
maintains the same position over a point on 
the earth, as seen from the earth it appears 
to remain in the same part of the sky and 
hence need not be tracked — the antenna 
can merely be lined up and fixed in place. 
The extreme altitude of these satellites 
means that most of a hemisphere can be 
viewed from them and they are an ideal 
camera platform for viewing the full earth 
disc or relaying signals from a ground station 
to any station within view of such a satellite. 
Table 3 summarizes the geostationary 
satellite systems of interest to amateurs. 
ATS 1 and 3 (ATS is an acronym for 
/Applications Technology Sateliite) are both 
experimental satellites to test the feasibility 
of hemisphere wide radio communications 
relays for a variety of purposes. One of the 
ways in which these sateltites are used is in 
the transmission of WEFAX (weather 
facsimile) pictures in the APT mode. These 
pictures are traremJited on a frequency of 
135,6 MHz on a regularly scheduled basis 
and include ** predict" messages for calcu- 
lating orbits of the various polar orbiting 
satellites, gray scale transmissions, and cloud 
cover pictures. The tatter are computer 
gfidded to show lines of longitude and 
latitude and geographic boundaries. Photo 2 
shows a typical transmission of WEFAX data 
from ATS 3 /If both satellites are in range of 
a given ground station it is possible to 
acquire ctoud cover pictures spanning the 
entire world. Both of these satellites have 
been in operation for several years and 
should they fail they will not be replaced as 
they are strictly experimental. The WEFAX 
program^ however, will be continued with a 
new series of geostationary satellites of the 
SMS/GOES type. The SMS satellites are 
prototypes of the operational system (SMS 
stands for Synchronous Meteorological 
Satclliie) while the GOES satellites 
(Geostationary Environmental Satellite) will 
be the operational versions. GOES I is 
scheduled for imminent launch as this is 
being written while SMS 1 and 2 are 
presently in orbit. These satellites produce 
extremely high resolution pictures which are 
transmitted to special ground stations for 
computer processing. Although reception of 
the original pictures is still impractical (not 
impossible^ it simply costs too much as yet), 
the computer processed versions are avail- 
able, along with other products, as APT 
WEFAX transmissions. The major drawback 
of these satellites is that transmission takes 
place on S band at 1691 MH/. Suitable 
converters for converting S band signals to 
the 137 MHz range used for reception of 



ATS and polar orbiting satellites can be put 
together from commercial components (8) 
but such an approach is prohibitively expen- 
sive for most of us. The subject of S band 
receivers will be discussed later. Just to show 
that the task is not beyond amateur capa- 
bility. Photo 3 is included as an example of 
SMS WEFAX reception. This particular 
picture was received by Roy Cawthon of 
Atlanta, Georgia, who has the only amateur 
S band system in operation at the time this 
is being written. |usi to show thai amateurs 
are not Jagging behind, Roy's station is one 
of only 5 in the world at the present time. 

All APT and SR satellite transmissions, 
regardless of frequency^ use FM modulation 



with 9 kHz deviation. 

Assembling a Satellite Station, There are 
very few references that provide all of the 
information you might require to sel up a 
station from scratch. Vermillion's NASA 
report (23) describes a long crossed yagi 
antenna, a tube-type FM receiver and 
preamp, and a CRT display system with APT 
capability and modifications for an early 
type of SR display. Later government publi- 
cations are available to update SR display 
for current standards. Kennedy (6) describes 
a completely up-io-daie display system 
including an FM receiver with a PLL 
detector to eliminate Dopplcr effects. The 
three part article is very complete and is 




Photo 3, An example of an SA^S S band (1691 MHx) WEFAX transmission as 
received and displayed by Roy Cawthon of Atlanta^ Georgia. Such pictures 
are derived from the very high resolution spin scan radiometer on th& 
spacecraft, which talies both visible and IR pictures of the full earth disc as 
seen by the satellite. The pictures are gridded on the ground and 
re-transmitted through the sate/ lite. Operational i^ersions of this series (GOES 
satellites) will transmit such pictures and a variety of other WEFAX products. 
The development of effective, low cost S band converters is one of the major 
challenges facing amateur satellite experimenters. 



55 



useful reading if you plan your own syitem 
design. The third source (21)^ is one I am 
particularly partial to simply because ! wrote 
ill This one book cor^tains all of the infor- 
matior^ required to construct a complete 
satellite receiving stztion including numerous 
accessories. The construction articles are 
complete and various options are presented 
for most system requirements. Chapters 
include antennas, receivers and preampli- 
fiers, CRT display systems, a FAX system, 
tracking, digital orbital timers, and ways co 
completely automate station operations. For 
those who would like to do additional 
background reading or who would wish to 
pul together a station based on several 
different options, the following references, 
grouped by subject, will be useful reading. 

Antennas. ATS or polar orbiting satellite 
reception requires the use of a circularly 



t 



To be pubiished In earlv 1376. 



polarized antenna with the gain require- 
ments for ATS being somewhat more strin- 
gent than for the polar orbiting spacecraft* 
(9) describes a very simple yagj for manual 
tracking that is suitable for polar orbiting 
spacecraft if you have someone willing to 
sand outside and operate it! (21) describes 
the construction of a short crossed ya^ 
antenna suitable for polar orbiting satellites 
and discusses various commercially available 
antennas suitable for ATS or polar orbiting 
systems. (23) describes a longer crossed yagi 
suitable for use with either ATS ot ESSA 
and NOAA spacecraft. (22) includes some 
interesting ideas on antenna mounting which 
might prove useful. You will notice the 
emphasis on crossed yagI antennas for 
circular polarization. This is simply because 
they have proved far easier to construct and 
mount than helix antennas, the other major 
alternative (3), (7). (3) contains useful design 
and mechanical data for crossed yagis in the 




Photo 4. Visible channel imagery tram a NOAA 4 SR transmission as 
displayed on a photographic FAX system. !n this case (he images from the 48 
line SR system were displayed at 96 rpm with alternate lines (the iR Image) 
electronically blanked. Such FAX systems provide extremely high quality^ 
especfally in defining the structure of bright cloud features. This particular 
pass (7 August 1975) was directly over the Great Lakes, which are faintly 
visibk in the center of the picture. 



Space Communications chapter. 

Reception of S band SMS/GOES sigrials 
requires a dish antenna. NASA recommends 
a 10 foot dish but Roy Cawihon has gotten 
by with a 6 foot version. The use of modern 
low*noise transistor may make possible the 
use of still smaller dishes in the order of 4 
feet_ I certainly hope so since my own 
four-footer is mounted in the back yard 
pointing hopefully skyward! (3) contains 
consuuction details for a 10 foot stressed 
parabolic array but this antenna would have 
to be modified for permanent service. 
Numerous microwave antennas available on 
the surplus market are also an excellent 
approach. 

Satellite Receivers. Satellite receivers for 
135-138 MU^ service should be FM with a 
30 kHz iT bandpass (15 kHz selectivity). 
This will accommodate maximum signal 
deviation {9 kHz) plus worst case Doppler 

shift (4,5 kHz), Crystal controlled channel 
selection with crystals for 135.6 MHz (ATS), 
137,5 MHz (primary NOAA), and 137.62 
MHz (ESSA and backup NOAA) will be 
rcQuired. Semitrviiy should be 0. 1-0.2 
microvolts for 20 dB of quieting. Older 
receivers will require a preamplifier to set a 
desirabfe front end noise figure* A preamp 
mounted at the antenna is highly desirable as 
it effectively overcomes line losses thai 
would otherwise degrade the system noise 
figure. 

Reference (23) describes a lube-iype 
receiver and mast-mounted preamp, (21) 
describes a kit, modifications to a com- 
mercial monitor receiver, commercially avail- 
able preamps, and tips on selecting a surplus 
receiver strip for weather sateliiie conver- 
sion. (6) describes a solid state receiver with 
PLL i-f that is very effective* Passable results 
can also be obtained by modi fica lion of a 
commercial FM tuner (9) but this is a very 
makeshift approach. 

Display Systems. There are two principal 
options for display of APT or SR pictures - 
a facsimile (FAX) recorder for priming 
pictures directly on paper and a cathode ray 
lube (CRT) display on a television-like 
screen tn which the imag^ is photographed 
for analysis. Both types of display systems 
are capable of resdving all of the picture 
details in either mode and each has its own 
advantages and disadvantages* FAX systems 
are mechanical devices which make the 
picture display immune lo factors such as 
stray magnetic fields that might distort a 
CRT display, yet they require some care to 
construct and operate and need some main- 
tenance to keep them in top operating 
condition. Some forms of FAX will give 
instant pictures with features visible during 
picture readout, while even the most 
involved photographic systems require only 
a few steps to view the picture. Some FAX 
systems excel at resolving fine structure in 
bright ctouds that might be obscured by 
trace blooming in a poorly designed CRT 
system. The mechanical nature of FAX, 



56 



however, means that you are fixed to a 
singfe size format and changing picture 
modes involves complex mechanical and /or 
electrical changes or the construction of a 
recorder for each mode you wish to operate. 
CRT systems^ iri contrast, are relatively easy 
to construct and building them for multi- 
mode service is an easy task. Direct viewiiig 
of pictures is difficult, however, and photo- 
graphs arc most desirabJe. This is one handi- 
cap of the CRT option, Polaroid film 
provides instant pictures but at some 
expense if you read out large numbers. Roll 
film provides very inexpensive recording of 
the pictures but at some delay while the film 
is processed and printed. Such photos can, 
however, be printed at any size desired. Use 
of a CRT system involves less "fuss" than a 
FAX display, which is a factor that makes 
it desirable in situations where only 
occasiona! use is required. Properly designed 
systems of both types will be about equal in 
overall performance so the selection task is 
complicated. Active satellite stations often 
have both types in operation to fit the needs 
at hand, 

The facsimile options are quite varied and 
a number of tradeoffs must be considered to 
determine which might be best for your use. 

The three major systems involve direct 
printing on film or paper using a modulated 
light source, printing on electrolytic paper, 
or printing on electrostatic paper. There is 
little doubt that photographic FAX systems 
offer the highest quality pictures — but at 
some inconvenience. They must be operated 
in the dark or near darkness in the case of 
systems thai print on paper, and photo- 
graphic processing is required. Anderson's 
pioneering work [2) describes a photo- 
graphic FAX system for APT use which 
prints on film* McKntght's modifications of 
this system (7) result in a system that is 
somewhat more convenient in that printing 
is done direLLJy on paper, thus reducing cost 
and lime required* Ruperto (1 1) describes a 
direct printing photographic system derived 
from the work of W6KT, and Taggart (20) 
provides a compfete construction article for 
a 48 line NOAA system aJong the same lines. 
Although both (11) and (20) arc designed 
for 48 line SR display, either could be 
modified for APT with little difficulty. (21) 
provides full construction information and 
design data for a FAX system for 48 or 96 
line SR display with modification notes for 
upgrading to future 120 tine SR systems 
(Photo 4). With very slight modifications 
this recorder (1 20 line version) could also be 
used for APT service. Printing on ciectrotytic 
paper results in some loss of Image quality 
bift this is compensated for in some situa- 
tions by the fact that the pictures can be 
printed out for immediate viewing in a 
lighted room, Winkler's SSTV FAX system 
(25) could be easily modified for SR or APT 
use — in fact, the SSTV version was a 
spin-off from his various satellite recorders. 
Photo 5 shows a sample of Winkler's APT 




f^oto 5. Dfsp/ay of art APT picture from ESSA 8 passing over the w^sf coast. 
This picture was displayed by Unsay Winkler using a homemade continuous 
readout FAX machine and Alden eltctroiytlc paper. Although such systems 
do not have the ultimate In fine detail of a photographic FAX or CRT 
system^ they are still excellent. Tire slight degradation In image quality Is 
compensated tor by the fact that the Image can be read out In normal room 
lighting and Is visible as It comes out of the machine. Similar continuous 
readout recorders are excellent for present and future SR systems as wetf 



readout on electrolytic paper — a picture 
from ESSA 8 in its better days! Electrostiitic 
paper is perhaps the least satisfactory alter- 
native, mostly due to the difficulty in 
getting a suitably good gray scale. Winkler's 
modification of a surplus Western Union 
Deskfax machine (26) is perhaps the 
quickest way to gel some sort of FAX 
system going. While hardly the equal of 
these other systems in picture quality, 
Osborne's FAX recorder (10) certainly takes 
the prize For originality — it is built up 
around a windshield wiper motor and gear 
assembly! 

CRT system options arc quite varied and 
many approaches are possible depending 
upon equipment already on hand. Three 
alternatives are presently the most popular — 
display on an oscilloscope, display on con- 
ventional SSTV monitors, or construction of 
a monitor tailored for satellite picture 
display. The oscilloscope approach involves 
construction oT a suitable *'black box" that 
will provide Z axis video modulation to the 



scope and appropriate waveforms for 
horizontal and vertical deflection. Osborne's 
circuit (9) is probably the simplest of these 
and Will give satisfactory results in the APT 
mode if a better receiver is used Toben's 
circuit (22) Is more complicated but will 
produce somewhat more reliable results. 
Kennedy's system (6) is the most elegant of 
the group and will provide exceflent results 
in both APT and SR service. 

The popularity of SSTV has led a number 
of people to experiment with display of 
satellite pictures on slow scan monitors, (13) 
fs a very simple APT adapter that can be 
used with a number of monitor circuits and 
suitable modifications for adding SR display 
are included in (14). Additional circuit ideas 
are incorporated in (17) that permit use of 
the adapter with Robot monitors or even TV 
sets. Owners of Robot SSTV equipment 
should consider contacting Robert 
Schloeman WA7M0V, who has designed an 
excellent adapter circuit specifically tailored 
for use with the Robot SSTV monitor. 



57 




Photo & A solid stale multlmode sateUlte monitor built by the author. This 
circuit is featured in the Weather Satelflte Handbook (21) and has 
switch-selected options for display of 48 line SR^ future 120 tine SR, and 
APT picture modes. Such tnonitors ate compact and are quite easy to 
operate^ making tiiem a highly desirable project for stations seriously 
interested in weather. Using all new components and high class packaging^ 
such a monitor still costs less than $300. Less elegant packaging and a search 
for junk box components can reduce costs to a fraction of this even in such a 
comparatively advanced project: 



The rconstmction of a complete display 
monitor is perhaps the most reasonable 
approach for Individuals lacking extra 
oscilloscopes or SSTV monitors. 
Vermii [ton's report (23) describes a monitor 
of sorts buHt around a commercially avail- 
able oscilloscope module. Spillane (12) des- 
cribed an APT monitor using tube circuits 
that would still be yseful with some modifi- 
cations of the sync detection circuits. The 
advanced version of Osborne's circuit (9) is 
another choice for APT display. (21) des- 
cribes a complete multimode solid state 
satellite monitor complete with printed 
circuit artwork and component layouts. 
Photo 6 shows a version of this monitor 
which is also described in (21). The tatter 
reference includes data on the simple addi- 
tion of 120 line SR capability which is 
incorporated in the unit shown (48 line SR, 
120 Nne SR, and APT capabitity). Such a 
monitor certainly represents the ultimate in 
a compact display system. 

Sateliite Tracking. Although tracking of 
polar orbiting spacecraft appears to be an 
imposing task, it is not at al! difficult to 
accomplish, (24) is Interesting reading 
regarding satellite orbits in general and (15) 
outlines all the essential features involved in 
satellite tracking. (21 ) contains a full chapter 
on the subject which in addition to the 
tracking of polar orbiting satellites also 
includes aiming data for geostationary 
satellites J alternate sources of tracking data, 
and a simplified model for long term orbital 
predictions. 



Accessories. These components include 
desirable station features that are not abso- 
lutely necessary but do improve operating 
convenience. (16) describes a digital orbital 
timer that eliminates the need to acquire 
daily prediction data or Interpolate from a 
clock when tracking and (18) describes the 
Ltse of such a timer to completely automate 
station operations, including turning on the 
recorder, trackings ahd station shutdown at 
the end of a pass. (17) includes some useful 
accessories such as an active 2400 Hz filter 
and a crystal controlled 2400 Hz reference 
source, either of which would be a useful 
addition to many of the systems covered in 
these references. Brush (4) describes a novel 
circuit for contrast enhancement in the SR 
IR channel display and (23) includes a more 
complicated circuit to accomplish much the 
same task for FAX display. 

This about covers most of the technical 
features. A very interesting summary of 
different weather satellite products is con- 
tained in a report by Hoppc (5) that not 
only describes the pictures from various 
satellite systems but also shows the different 
ways in which these are computer processed 
and mosaicked for greater utility. If you get 
a system in operation you might wish to 
learn a little more about how the cloud 
systems you see reUte to surface weather. A 
wealth of information on this subject is 
contained In Anderson's paper (1) which, 
with a little study^ will enable you to derive 
really meaningful data from your cloud 
pictures. 



Now there are probably lots of readers of 
this article who might never consider setting 
up a satellite station. You have read this 
article out of curiosity and the desire to 
simply learn a little bit about another facet 
of this far-flung hobby of ours. This is one 
of the things that makes It interesting to 
receive your magazine every month. But 
even if you are not interested in weather 
satellites, let me outline a challenge that may 
appeal to some of you. I have mentioned 
previously the difficulties involved in putting 
together a suitable S band converter for use 
with the SMS/GOES satellite series. The 
commercial modules (8) are far too expen- 
sive for most satellite buffs and Roy 
Cawthon's success was due in large part to 
his willingness to invest a fair amount of 
money and a huge block of time in getting 
his system going. It is not one that could be 
easily duplicated by stations now receiving 
ATS WEFAX who would like tb get in on 
the action up on S band. Several amateurs 
are actively working on the design and 
construction of suitable S band converters in 
the hopes of pushing down price and com- 
plexity to the point that others could think 
seriously about adding S hand capability to 
their operations. It is too early to say if 
these efforts will be successful but it is a 
virtual certainty that a lot of you out there 
are seriously interested in UHF and micro- 
wave experimentation. A successful S band 
converter would be a boon to satellite 
stations throughout the world and there is 
no doubt that should any of you develop 
such a system, you could certainly put 
together a description of the circuit that 
would instantly be accepted by a magazine 
hke 73. The specifications run something 
like this: 

Input Frequency — 1691 MHz 

Output Frequency — 137,5 MHz 

Front end noise figure — 2.5-4.5 dB 

Front end gain ~ 20 dB min. 

Mixer noise figure — 9.5 dB max (assuming 

1.5-2 dB first if noise figure) 

NASA's solution is a $900 preamp, a $200 
mixer, and a S900 LO chain for a total 
converter cost of $2000. With today's tech- 
nology it would seem that amateurs could 
do the same job for $200 — maybe a little 
more, perhaps somewhat less. Any UHF or 
microwave buffs out there who would like 
to give it a try? I would be happy to 
correspond with anyone who would. Any 
approach is valid although perhaps micro- 
striplines are best from the point of view of 
easy duplication. Maybe you like to design 
but hate to build, in which case micro- 
stripline design data around specific rf tran- 
sistors would be most welcome — needless to 
say full credit would be given for any 
successful design input. Perhaps you have 
access to suitable S band test equipment and 
would be willing to help set up gear that 
others might construct — if so I would 
certainly like to hear from you. An easily 



58 



duplicated S band converter would make 
you famous in weather satellite circles even 
if you never watch a single picture - see 
how easy it is to get involved? Hundreds of 
APT stations throughout the world will be 
out of business in ternns of WEFAX if such a 
converter is not forthcoming before the ATS 
satellites expire. This one area is certainly a 
challenge to anyone with the expertise to 
once again show the "professionals" what 
amateur radio c^n accomplish. The more 
people who are working on this particular 
task the more certain will be an eventual 
solution! 

Experimenting with weather satellites is 
certainly one of the more fasclnatmg 
peripheral areas In which amateurs can 
participate. One of the simpler systems 
represents an ideal short-term project to 
discover if you might be interested, but even 
the most sophisticated systems, equal to 
commercial display units costing over 
$10,000, need not be expensive. The multi- 
mode monitor shown in Photo 6 is capable 
of displaying pictures from present and 
future APT and SR systems and yet even 
with the comparatively "deluxe" packaging 
employed it can be built for less than $300 
— less than a commercial SSTV monitor. For 
less than what some amateurs are willing to 
spend on one of the newer FM transceivers it 
is possible to construct a complete satellite 
station that will operate when you aren't 
even home* Stations with fewer refinements 
have been constructed by students as science 
fair projects for a small fraction of this cost. 
Why not look through some of these 
references and give it a try? ■ 



Literature Crted 

(t) Anderson, R,K, et ai. 1974, AppEtcations of 
meteorological satellite data in anaivsis and fore- 
casting, ESS A Technical Report NESC 51 
(reprEnth$1.75* 

(2J Anderson, W. 1965, Amateur reception of 
weather setetlite picture ir@nsnnissions. QST, 
IStovember. 

(3) The A.R.RX. Antenna Handbook. American 
Radio Relay League, Newingion CT, Chapter 12, 

(4) Brush, RJM. and P.E. Baylis. 1973. Contrast 
expansion processor, Wft&ls$s Worlds Decemts^r. 

(5J Hoppe, E.R. et aL 1974. CataJogs of opera- 
tional sate Kite products. NOAA T&chnicai Memo- 
randum NESS 55. $3,00* 

(6) Kennedy, G.R. 1974. Weather satellite ground 
station. Wir&f&ss World ^ November, December and 
January 1975. 

(7) McKnight, C. 196S. Evolution of an amateur 
weather satellite picture station. OST^ ApriL 

(8) t^agle, J.H. 1974. A method of converting the 
SMS/GOES WEFAX frequency (1691 MHz) to the 
existing APT /WEFAX frequency (137 MHz). 
NOAA Technical Memorandum NESS 54. S3. 00* 

(9) Osborne, J. M, 1971, Receiving weather pictures 
from ssteJIltes. Wire/es^ Worid; basic system in 
October issue, advanced system in JMovemtaer issue. 

(10) Ibid. 1975. Facsimile scanner. M^/re/es? l^or/d, 
October^ 

(11) Ruperto, E.F. 1974. Weather satellite pictures 
picked up in the home. Amateur Scientist section. 
Scientific American^ January, 



M2) Spillane, J. 1969. A cathode ray tube display 
unit for satellite weather pictures. QST, June. 

(13) Taggart, R;E. 1974. Western satellite pictures 
on your SSTV monitor, 73 Magazine^ September. 

(14) tbid, 1974. A modified WB8DQT satellite. 73 
Magazine^ December. 

(15) fbtd. 1975. How to find the satellite. 73 
Magazine^ January, 

(16} ibid, 1975. What time is the next satellite? 73 
Magazine^ February, 

(17) ibfd, 1975. More weather satellite pictures. 73 
Magazine, June. 

(1S) ibid, 1975. Automating satellite reception. 73 
Magazine^ July. 

(19) tbid. 1975. How about a weather satellite 
monitor? 73 Magaiine^ August. 

(20) tbid. 1975. A satellite fax system you can 
build. 73 Magazine, September, October. 

{21) Ibid. 1976- Ttfe Weather Sat&fh'te Handbook. 
73, Inc., Peterborough NH 03458. 



(22) Toben, G.H. 1968. Electronic system for 
recording satelJite transmissions. Ham Radio, 
November. 

(23) Vermillton, C.H. 1969. Weather satellite 
picture receiving stations, NASA SP-5080. $3.00* 

(24) Widger, W.K. 1974. A plotting device for 
predicting the orbit of an earth satellite. Amateur 
Scientist section. Scientific American, May. 

(25) WinkJer, L. 1973. A fa^t scan facsimile system 
with SSTV cornpatabjlity. 73 Magazine, March. 

(26) ibid. 1974. Facsimile transceiver for yyeather 
satellite pictures. Technical Correspondence, QST^ 

May. 

* References marked with a single asterisk are U.S, 
government pubiications which are avail abie from 
the National Technical information Service, U.S. 
Department of Commerce, Sills Building^ 5235 
Port Royal Raad^ Springfield VA 22151. Such 
govarnment publications are also available from 
large public libraries or uni\/ersities with holdings 
of government documents. 




i^*^ 



'■■•V ^— »Si^:i ■•>:- ■ 



■■¥■ 




*s- 






1 i 



■ssii_^: 



Photo 7. One drawback in improper/y operated CRT display systems is that 
trace '"blooming*' often obscures fine features in very bright clouds. This 
photo of a NOAA pass over the central U.S. on a very cloudy winter day 
shows that properly operated CRT systems need not have this problem. This 
particular picture was displayed on the 5'' CfiT monitor described in 
reference (19), 



59 



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DIES 

OF 

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THREE YEARS OF 73. . . .ONLY $1776 (while they last) 

This offer isg(X)d only through July 4ih 1976 (unless we change our minds I 

Here*s a chance to get a tiintastic buy , . . $54 worth of 73 magazines for only (only?) 
$17.76. You don't get much better buys than (hat! 

You may not have noticed how great 73 is these days , , . in case you haven't Just take 
our word for it. When have we ever tied to you? 

Heyl That comes out to under 504 a copy . , . that*s ridiculous! Considering the new 
postal rates it won^t be long before the price will be SI 7.76 for two years . . . then one . . . 
and, within the forseeable future , . , $17.76 for each issue. How about those fellows who 
bought LIFE subscriptions? 

Oh, you may enjoy 73 now , , , perhaps you weren't one of those dragged kicking and 
screaming into FM a few years back when Wayne found out how much fun that was and 
decided to push the hell out of it for a while. You may get fed up with Wayne*s enthusiasms 
, , . like when he decided that SSB would replace AM back in the 50's and he pushed that 
hard. Despite what you may hear from unmentionable sources, Wayne is not always wrong 
, . . no one is perfect, even at being wrong. 



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lit iCi KID HQ D Okk E3 

iEiniililAl 





iiiiimi 



THREE YEARS OF 73 MAGAZINE $17.76! WOW! 



IMame 



Call 



Add ress 



City 



State 



Zln 



□ New Sub nStart with May Issue DBankAmericard 

□$17.76 Enclosed nRenewal or Extension □Master Charge 

□Bill Me 

Card Number 

Signature 



BUY CENTENNIAL BUY - 73 MAGAZINE - PETERBOROUGH NH 03458 



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63 



The 
UN-COMPUTER 




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The first thing t would like to say is 
that I think you have a very fine 
magazine. You sure did 9 good job of 
getting my interest back inio ham 
radio. 1 picked up your Navennbef 
issue out of curiosity, as I was 
brousing around a ma^ziiie ooynter. I 
had a riovice license back in 1967 and 
1968 when I was in Ngh school. But 
after that I sort of lost interesL As a 
result of that issue, I also picked up 
your January issu€, which was as good 
as the other, if not better. Your 
influence caused me to pi^rchase your 
14 wpm tape to help get the o^ code 
speed up to ai least a tolerable level 
by the FCC, 

Now for my problem, I would 
appreciate ii If any of the readers in 
the Warminster, Pa, area have any 
information about ham clubs in this 
area. I would like to get involved with 
Orte, plus at itie same time It will help 
me to get back on r?iy feet again. 

William K. Seitzinger 

753 Cheryl Drive 

Warminster PA 18974 

675-6252 



Helpl 



Bret Marquis 
1843 Gqean Front 
tM Mar CA 92014 



Put my name in your Ham Help 
page. I can help a Novice, Tech^ or 
Genera] with the basic theory, and if t 
dor»*t know the answer to some of 
their questions I know a number of 
people who do. 

David W. Thompson 

1412 15th Ave. 

ParkersburgWV 26101 

Please add our names to ur list of 
Ham Helpers: 

Lou (WB3Nf^U) and 
Annette (WBftPZMl Hinshaw 

PO Box in 

Hays KS 67601 

Phone: 625 7768 

Please add my name to your list of 
amateurs who are willing to lend 
assistance to aspiring newcomers to 
the fraternity of amateur radio. Also, 
may 1 say thanks fof publishing a fine 
business ham nriagazinie. 

Btcanlo H. Nabor K9GY0 

4926 So Lotus Av«. 

Chicago I L 60638 

I need help brushing up on theory 
and putting my station back on the 
air. 

TonyCarlozziWNIUHU 

88 Bantett Sl 

Brockton MA 02401 



M 



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Please send me my FREE Heathkit Catalog 



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407- 1 5th Avenue 
Sierhng IL 61031 



Scan Your HR2I2 



W minting ionri€ type of scanner for my 
Regency HR2i2^ I got out all my 
ham magd/incs and came upon the scanner 
described by K2LZG in the February 1973 
issue of Ham Radio, I had never built 
anything using ICs, so I said to myself you 
might iis well get started now as never. After 
many nights of burning ihc midnight oil, I 
finatfy came op with the right hookup for 
theHR212. 

The channel selector m the HR212 
applies a ground to the appropriate rf choke 
{L501 through L512) which places a for- 
ward bias on the diode. This action provides 



7400 



an rf path for the crystal to turn on. 

I use a +2 volt signal to stop scan and a 
zero volt signal to enable scan. You can take 
the squelch voltage off the white jumper 
wire which is located near Q105 and CI 37 
located on the i-f-audio board. You can pick 
up the 1 2 volts anywhere after the on*off 
switch; I look mine off the red wire on the 
on-off switch. To connect the six oscillators 
to the scanner I connected six wires, one to 
each rf choke (L501 ihrough L506)_ Be sure 
to connect to the side of the choke going to 
the channel switch, I built my unit in a small 
plastic case obtained at the local Radio 
Shack, I used a small mate jack mounted on 



the back of the box and brought the nine 
wires out the HR212 to the female plug- 
Also, I mounted six SPST toggle swiichcs in 
series with the oscillators to the scanner, so I 
can switch ^ny channel out I don't want to 
monitor. I mounted a SPST switch in series 
with the 12 volts to the scanner to switch 
off the scanner when I want to transmit. ! 
use a MAN-1 7 segment readout for the 
channel indicator. 

To use as a scanner just turn the channel 
switch 10 any unused channel and flip on the 
12 volts, and scan away to your heart's 
content. ■ 




TO RF CHOKES 
O L50r- L506 
IN HR2k2 



27K 
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S9= SPST NORMALLY CLOSED PUSHBUTTON 



+ 5 



THE NINE WIRES FROM HR2i2 TO SCANNER ARE 
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The perfect tonic for power 
Supplies with a farad oEri- 
CTENCY. Axial lead package 



and a special for 
I/O people: 

We*ve ryn into a bynch of 3? uf # lOV TANTALUH capaci- 
tors. These ^rc Kemet type TJIO, buUet shap«d capaci- 
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Hits capacitor is fine for byp«ssing ^Tth TTL and otHer 
logic families. HarmaMY these go at V$KOQ; but if 

yoy get your order in by April jOth and tinention the 1/0 
page, you cart get 20% off-*-5/Sl »00, 



ALL THESE ncnORY BOARDS ARE PLUe-TN COIIPATISLE UITH THE ALTAIR aEDD 



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NOW rOU CAN STUFF U? TO SK OF SOFTWARE- --EDITOR/ ASSEMBLER OR 
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So you^ve got yourself a microcomputer* * -only to find out yoo 
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RAM 



SI 09.22 



With this kit you get sockets for all ICs , Indus trial -quality plated- through board, lota of bypassing, five 
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time ^ ^5'C^ and buffered addresses and outputs (no Input presents more than 1 low power TTL load; output 
can drive 20 standard TTL loads). Requires 5V @ lA at 25**C. Comes with assembly hints and logic print of 
the RAM board. 





sua CKX>BOUT aECTtONICS 
SQK 2355. CSAKLANO ARPORI CA 5*4614 



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by Wayne Green W2NSD/1 



EDITORIAL 



WANT TO MAKE A BUNDLE? 

Not to be a r^ame dropper, but sure 
as God made Yellow Transp^feni 
apples fto me the finesi apples in the 
world) someonie may make a fortune 
by Doming up with a small oomputer 
system for small business and home 
usie ... if he plays bis^rds fight. Best 
of all, mthtog further has to be 
invented to make this a reality . , , 
some of the pjece* have only to be piJt 
together* 

Sinca a smaJ! black and white tele- 
¥tsion set retails for around S6S, a 
keyboard for S30, a microcompyter 
chip ^r $20, a cassette recorder for 
S20, how much could a small com- 
puter system cost embodying these 
elements? Oh. you'd need a display 
generator for the TV, an interface for 
the casette, and some working 
memory, I'll bet someone oou!d pot 
such a contraption on the market for 
under $1000 in siic months . . . and 
Ifie price would be down to half that 
in six more . . . and eventually down 
to maybe $250 .. or $T2S. The 
prices go down a foi when chips come 
available to handle each function . . . 
and eventually the whole works. 

They're already starting to put 
RAM memory on CPU chips . . . and 
I/O interfaces too. Add a small built* 
in ROM operatrn?] system and a TV 
display generator . . . and the price 
plummets for a complete small Qqm- 
p liter system- 

Do you want to wait for someone 
efse to get into the business or start 
working on it yourself? Here's a way 
for someone to invest some time and 
money in a project which could be 
worth millions in a couple of years. 
MITS had about 15 people when they 
entered the uP business .. , now look 
at 'em I 

HAM COMPUTING 
(Wosl of us can think of a lot of 
good thir^gs wt might do if we had a 
computer ... like keep track of 
stations oont^ited along with some 
details about them . . , maintaining an 
Index to tiam magazine articles that 
we might want to look up . , . deter- 
mining Oscar intercept t*r«es and bear- 
ings . . . running all the functions of a 
repeater , , , playing any of the 
hundred or so popular computer 
games . . . getting into computer art 
forms with a color television set . . 
experimenting with computer music 
. . , keeping track of nepeater channels 
and location . . . Morse code conver 
^n , , , RTTY operation . . . thirigs 
like that. 

But the next questioo rs a tough 

one what hardware will it take to 

get involved in my interest . , . and, 
even more difficult, what programs 



, , * and where can 1 either get the 
programs or get the training so I can 
develop my own pnograms? 

Frankly, we could use a lot of Input 
on both fiard and software. Let's see 
some articles ori thts . . , sfx^wing 
configurations of available gear which 
will do ham and hobby jobs. 

If we took at the Sphere equipment 
we see that for most ham applications 
we will need tfteir "200" system, their 
"B" package and BASJC on cassene. 
This comes lo S860 for the "200," 
$205 for 1 tie extra 4K f^AM memory 
and character generator ROM of 
package "B" and $100 for BASIC on 
a cassette ... total S1 165 for the 
hardware. Now, if you buy ttie BASIC 
teictbook by Albrecht f$4h you will 
be ready to go with atmost any 
program you want, doing your own 
programming. The DEC 101 Games in 
BASIC \SI} wilf launch you into the 
game biz. You will need a television 
set for the display. 

The Sphere system wit I give you the 
computer, a character generator so 
you can read out the input and output 
of the system on a television set, a 
keyboard for inputting, BASIC pro- 
gramming language which takes about 
5K of RAM memory, leaving about 
3K for your use, and an I/O for a 
cassette recorder for use m entering 
programs, storing programs for later 
use, and storing data in long-term 
memory. That's a fairly comptete 
small system. 

II you want to go the MITS route 
you'll need an Altair 680 {$420}, 12K 
of RAM memory ($825}, an I/O port 
to Interface the 680 with a video 
disptay terminai f$T44), BASIC 
language on cassette ($75), cassette 
interface I/O port (Si 44}, plus some 
sort of video generator and keyboard 
unit such as the Southwest Tech kit 
which runs about $2B2 (and then you 
have to build it , . . which is fun). The 
cost of ihis system would appear to 
come to around SI 890. If you want 
to go the Altatr 8600 route . . . and 
Ed Roberts points out in the Altair 
Cdmputemotes publication that the 
8080 chip is substantially better in his 
estimation than the 6^X> difp . . . this 
would increase the cost even more. 

The Altair SSOO computer is S621, 
eKpander boards are S93, a cooling 
fan is S20, three 4K RAM boards are 
^25, the cassette I/O is St 74, ihe 
television typewriter I/O is ST 44 and 
BASIC tarwjuage on cassette is S75, 
plus the S282 for the TVT kit comes 
to $2234. 

To do any work involving data you 
want to keep on file you will reed a 
coupie more cassette control systems 
so you can use one cassette for your 
data base, a second for any update to 
the data base, and a thrrd for the 



updated data base. This means two 
more 1/0 interfaces and control 
systems , , , it also means a lot of 
programming using BASIC. If you 
warn to keep a file of every station 
you've contacted and be able to 
quickly get the data on someone, this 
is the system you'll probably want. 

The same system would work fine 
for keeping track of ma^zine articles 
you might want to reference, recipes 
for the wife, addresses for a club, a 
file on music in your record Collec- 
tion, a list of n waters, etc 

These systems will be a little slow 
in locating data in memory since they 
will have to scan your cassette tape 
for the <^ta file wanted. It won't be 
long before we have relatively inex- 
pensive tape systems which can be 
searched much faster . . , and rela- 
tively low cost floppy disk memory 
systems afe on the way. Disks don't 
hold moch more ^an cassettes, but 
tfiey search very rapidly. 

There are a lot more small com- 
puter systems coming along, but I 
haven't got much data on them as yet. 
It Is almost impossible to understand 
some of the advertrstng literature in 
this field and even talkir>g with the 
manufacturers can be frustrating, for 
some of them are so busy designing 
and turning out parts of their systems 
that they haven't given miffih thought 
to what it will be used for . , . or what 
problems the user may run into- 

I would like to state that 73 is most 
anxi^ous to hear from any ham com- 
puter hobbyists who have managed to 
put small systems together and get 
them to actual iy do something. Please 
tet us know what you are using and 
how you programmed it. I would also 
be delighted to hear from any manu- 
facturer who can state just what hard- 
ware and software is needed . . . and 
how much it will cost ,,, to set up 
some hobby systems such as outlinied 
above. 

for instance, any of the small 
systems being marketed are quite 
ca4:»able of calculating the Oscar 
acquisition times, but where can you 
get the program for the calculation? 
Untess it if in eilher machine lartguage 
for your partioilar chip or in BASIC, 
you won*t be able to cfo much. And ft 
has to be In a BASiC that is com- 
patible with the BASIC yi^u've got for 
your computer, just to make matters a 
little more complicated, for there are 
BASICS and then there are BASICS, 
from Mini- BASIC on up through 
E^ctended BASIC. Obviously we all 
need to know a lot more about this 
situation . . . arnl get some cour^^l on 
where to get tfte programs we need for 
Oscar ^ mooribounce tims, etc 

Now is the day of the true pioneer 
as far as microcomputers are con- 



cerned ... like sideband In the 
mid-SOs . . . like FM in T969 . . . and 
RTTY in the late 40s. We are a long 
way from the appliance operator 
phase of uP systems and these are the 
days which separate the men from the 
boys. Let me emphasize again that 
having fun with computers does not 
take super brains ... it does not take 

a wf>ole tot of money It does not 

take education ... aN it takes is 
enthusiasm and persistence. And, if 
you are young in spirit, there is a very 
good chance thtat you can parlay your 
knowledge into a very comfortable 
living, 

THE MAGIC OF 
FRESH ORANGE JUICE 

The other morning, as I was squeez- 
ing oranges, I had a depressing 
thought. I remembered a bit on a 
recent Today show lauding the 
wonders of Florida, It was a film 
about the citrus industry there and 
they mentioned that two thirds of the 
Florida oranges are now processed 
into frozen concentrate. How many 
years since you have had fresh orange 
juice for breakfast? 

Once you get into fresh orange 
juice you have a tough time gagglr^ 
down the frozen stuff , . , or the 
"Fresh" juice in cartons. You have to 
totaEly forget what orange juice tastes 
like to accept frozen. An electric 
juicer runs around $10 to $12.50 
{Unity Of Sears) and you can crank 
out a glass in about a minute . . . you 
don't thaw out a can of frozen much 
quicker. 

Just as we have all come to accept 
the frozen juice alternative to doit- 
yoursetf juice, with a loss of sub- 
stance, most of us hams have come to 
accept oiir ham gear as either ready- 
buitt or in kits (paint by the num- 
bers?) « I have a strong feeling that the 
computer revolution in amateur radio 
win bring back a lot of the home 
squeezed flavor to our hobby , , , for, 
even if you work from an assembled 
or kit computer, you are stiH only 
about 25% of tf*e way toward your 
goal. This is one field where the 
hardware is only ttie start and merely 
opens the gates for self-expression und 
creative fun via the programming you 
wilt be doirxi. 

1 hope ttiat the manufacturers of 
computers won't be angry at me for 
letting the cat out of the bag, but the 
fact Is that ^tting your equipment 
w>rking is only a small part of the fun 
and cfiailenge. Oh, in time a tot of the 
Mork will be done for you and will be 
available on tape or something . . . 
perhaps ROMs. At least, programs will 
be available for ordinary uses of the 
equipment . . . you will still be on 

Cof7rtm/ed on pags 35 



69 




John A. Lehman WB8TUR 
716 Hutch im #2 
Ann Arbor Mi 4B1QS 



Computer Languages 




Anyone who wants to 
use a computer has to 
have a way to communicate 
with it. This article is a simple 
introduction to some of the 
languages which are used for 
that purpose. It is intended 
for rank beginners, so all of 
the programmers, software 
freaks and computer hot dog$ 
in the audience might as well 
stop here. For anyone else, 
l*m going to try to keep 
everything in English (which 
is not a computer language^ 
unfortunately) and avoid as 
much computerese as 
possible. So here goes. 



t i 



One might start by asking, 
Why have computer 
languages at all?*' Back in the 
dark ages 25 or 30 years ago 
they didn't - the machines 
were wired up to do a certain 
thing and that's what they 
did. But, somewhere along 
the road» some bright fellow 
realized that it would be 
much more efficient if you 
could feed the machine a 
fairly long set of instructions 
and let it follow them. This 
also made for much greater 
flexibility, since you could 
give the machine different 
sets of instructions. These 
instructions are what a com- 
puter language communi- 
cates, and this article will go 
over some of the more com- 
mon ones J to wit: Assembler, 
BASIC, FORTRAN, PL/I, 
COBOL and a little bit about 
some of the more specialized 
ones. But first let's look a 
little bit more at the nature 



of the beast we're dealing 
with, 

It is helpful to think of a 
computer as a glorified elec- 
tronic calculator. In fact^ 
some of the more modern 
calculators really are com- 
puters. But let's look at the 
average four function calcu- 
lator. It has a display^ which 
is called an output device In 
compulerese, and it has a 
keyboard, which is an input 
device. To do anything with 
it, you have to enter the 
numbers through the key- 
board and then enter what 
you want done with them, be 
it to add them or whatever. 



machine which get done 
without your standing there 
pushing all of the buttons 
each time. But now we have 
to get this set of insiruciions 
inside the machine, and that 
is where programming 
languages come in. We need a 
way to communicate the 
instructions to the machine. 
In the case of a calculator, 
this isn't much of a problem. 
The "Instruction Set" (list of 
alt of the instructions which 
the machine is able to follow) 
is hard-wired in. If you want 
it to add, you push +, This is 
obviously not too good an 
idea For a large computer, 
since the number of buttons 



Machine language is the closest we can get 
to what the machine actually speaks. 



But suppose you want to do a 
mortgage calculation - say^ 
figure out what your interest 
payments and principal pay- 
ments are going to be each 
month for the life of the 20 
year mortgage. This means 
that you're going to have to 
do a very repetitive calcula- 
tion 240 times. It is to avoid 
this sort of hassle that real 
computers (and some fancy 
calculators) have stored 
program capacity — a stored 
program being nothing but a 
set of instructions inside the 



gets pretty large. Besides, you 
tend to run out of symbols, 
which makes everything even 
more confusing. So we need 
some sort of language. The 
simplest one is called 
"machine language" and is 
the closest we can get to what 
the machine actually speaks. 
However, as any of you who 
have been rollowing the 
articles in 73 about gates and 
such know, computers and 
other digital machines run on 
high and low levels of voltage. 
Since this is rather hard to 



seCj we usually represent it 
with ones and zeros, or on 
and off lights. ITie whole 
thing is like trying to com- 
municate using RTTY but 
doing il by ear instead of 
with a TTY machine^ which is 
to say that it*s a royal pain. 
Anyone who's into inter- 
preting things tike 01001101 
OnOOCX)! and so forth can 
really get off on it, but for 
most of us there's gotta be a 
belter way. Fortunately there 
is. Incidentally, if you ever 
get a microcomputer, those 
switches and lights on the 
front panel are used to com* 
municate with the thing in 
machine language. 

The next sort of language 
developed, and the one which 
is most widely available for 
microprocessors these days, is 
the assembler. Each type of 
computer has its own version; 
what it is, in short, is machine 
level logic — but using 
symbols and normal numbers 
rather than ones and zilches. 
Assembler is related to what 
you do with a calculator — in 
fact, any of you who own or 
use HP calculators have been 
using a version of assembler 
language usually known as 
Reverse Polish Notation, With 
an assembler language, you 
specify what number you 
want J where you want il put 
and what you want done with 
it; for example {to use HP 
assembler): "12, ENTER 
[wft/c/r puts it In the region 
where the arithmetic Is 
done], 2, x" muUipiies 12 
times 2 and comes up with 



M 



70 



24. All assembler languages 
work this way, although 
many of them have dozens of 
commands and hundreds of 
locations where things can be 
put or obtained. This sort of 
computer language has a lot 
of advantages. It's very 
efficient not only where 
memory is concerned, but 
also with regard to execution 
time. This means that it's 
cheap to use. The assembler 
(the program which translates 
it into machine language) 
doesn't take up much 
memory either, which means 

it can be used in a micropro- 
cessor which doesn't have 
much memory (and memory 
costs like the devil, even these 
days). Using assembler, you 
can also anticipate situations 
where the machine might do 
something unexpected, since 
you're on the machine's 
logical level. Of course, it's 
got Its problems too. It*s hard 
to learn, not easy to use welt, 
hard to debug (find errors) 
and is "machine dependent/' 
which means that each 
machine has its own. To sum 
it upj a tot of people don't 
like to have to write: 
"12, enter, 2, x." They'd 
rather write *'A=1 2 x 1" This 



is what *'high level" languages 
let you do, along with all 
sorts of other convenient 
things. For this reason, 

almost all programming these 
days is done with one of the 
various high level languages, 

and the rest of this article will 
be about some of the more 
common of them. 

First of all, a higfi level 
language is a computer 
language that is based on 
some combination of English 
and algebra. So, to write two 
plus two you would usually 

write "2+2.'^ To tell the 
machine to print, you write 
PRINT, WRITE or something 
of that nature. Ttie one thing 
to watch out for is that, 
although there are many 
different ways of writing one 
thing in English {and to a 
certain extent in algebra), a 
high level computer language 
has a very narrowly defined 
structure and vocabulary. 
This means that the computer 
equivalent of 'M ain't got 
none" will be rejected. In 
other words, you have to be 
very careful when writing any 
sort of program for a com- 
puter, since errors (the conv 
puterese term is glitches) get 
caught faster than they would 



be by an old-fashioned high 
school English teacher. 

Continuing the compar- 
ison with human languages, 
there are lots of different 
ones for computers, too* At 
first each company developed 
its own; now many of them 
arc standard and thus can be 
used on any machine with 
feWp if any, changes — unlike 
assembler languages. We stilt 
have a lot of computer 
languages, though. For 
example, the last time I 
checked the documentation, 
there were something like 35 
different high level languages 
available for use with the 
University of Michigan com- 
puter system. The reason for 
having so many is that each 
language is designed to do 
some particular thing well (in 
jargon, they are problem 
based rather than machine 
based). This means that one 
language is good for mathe- 
matics (also called number- 
crunching), one is gold for 
electronic circuit design, 
another for library use, and 
so forth. There are also a 
couple of general purpose 
languages - which happen to 
be the most popular for 
obvious reasons. 




It would be a pain to have 
to spend a few weeks master- 
ing a new computer language 
every time you wanted to do 
someihing different with a 
computer — not to mention 
that you have to buy (or 
write) a special translating 
program (called a compiler) 
for each one — and that can 
get very expensive (much 
more than the cost of the 
computer itself). So let's look 
at some useful, fairly general 
purpose languages. 

BASIC, which stands for 
'* Beginners* All-purpose 
Symbolic Instruction Code," 
was developed at Dartmouth 
College a number of years 
back, it was designed for 
people who knew nothing 
about computers but who 
wanted to use them. Few 

dyed-in-the-wool program- 
mers care much for it, but 
most non-programmers love 
it. It's based on algebra, and 
the non-algebra parts of it are 
in plain English. For example, 
to enter two numbers into 
the machine, multiply them, 
divide one by the other and 
print the results, you would 
write: 

1 IN A, B 

2 LETC= A*B 

3 LET D = A / B 

4 PRINT QD 

{* is the standard symbol 
for **times'* on a computer) 

This language has quite a 
few advantages. It's easy to 
learn, easy to use, and there 
are lots of books around 
which help people learn it. 

Equally important, there are 
lots of programs already 
written and published in it 
(these are called canned pro- 
grams), and quite a few com- 
puters can use it. In pa^tict^ 
lar, Altair has two (going on 
three) versions out at the 
moment, and other micro- 
computer manufacturers are 
making noises about supply- 
ing it - or so I read. The 
compiler (remember, that's 
the program which translates 
the things you write into the 
machine's language) doesn't 
take up too much memory 



7t ^M 



either, which means that 
BASIC is suitable for small 
computer systems where 
memory is limited A final 
advantage is that BASIC is 
fairly flexible - especially the 
advanced systems. You can 
do many if not most of the 
same things with it as you 
could do with FORTRAN or 
PL/1, although the program- 
ming effort might be greater. 
It does have some disad- 
vantages, though, BASIC has 
no mnemonic variables. This 
means that yoo have to 
remember that A stands for 
current, E for voltage and so 
on. In a more advanced 
language you could write 
AMPS, EMF, etc. This isn't so 
bad if youVe working with 
standardized symbols, but 
gets to be a disadvantage 
when you try to remember 
which was Accounts Payable 
and which was Accounts 

Receivable. Also, BASIC is 
somewhat limited as to what 
you can do with Input/ 
Output. This only makes a 
difference if you are working 
with a big system that gives 
you lots of choices — it isn't 
of too much concern for a 
home computer system or a 
small business one. Finally, 
BASIC is structured some- 
what along the same lines as 
FORTRAN, which is the 
oldest computer language still 
in use. This means that it 
does a lot of things in harder 
more roundabout ways than 
some of the newer languages, 
like PL/L For example, its 
*'either-or" choice is rather 
cumbersome to write. It's still 
a great language to play 
around with, though. 

FORTRAN is probably 
the best known of the various 
computer languages, partly 
because it*s one of the oldest* 
The name stands for FOR- 
mula TRANslation, and it 
was developed by IBM back 
in the early 1950s. It and the 
B-Zero language developed by 
Univac were the first high 
level languages used. No one 
uses B-Zero today (few have 
even heard of it), but 

72 



FORTRAN is probably the 
most widely used computer 
laoguage in the United States. 
Of course, the FORTRAN we 
use now isn't the same as the 
FORTRAN introduced back 
in 1957 — just as the English 
we speak now isn't the same 
language as the people in 
England spoke back in 1066. 
There have been three official 
versions of FORTRAN: 
FORTRAN (the original), 
FORTRAN II and 
FORTRAN IV. Number three 
got lost in the middle some* 
where. Most computers these 
days use FORTRAN IV, 
although there are some mini- 
computers around that still 
use FORTRAN II; some oF 
these compilers might be 
adaptable to microcomputer 
use. Anyway, as you might 
guess from the name of the 
beast, FORTRAN is basically 
a scientific computer 
language; it was developed to 
make it easier to solve mathe- 
matical-type problems for 
science and engineering. Over 
the years the language has 
expanded to the point where 
it is usable as a general pur- 
pose language, so it can do a 



ptiter, the compiler (remem- 
ber? the program which trans- 
lates it into machine 

language) takes up much 
more memory than a BASIC 
compiler, though much less 
ihan one for most other high 
level languages. One keeps 
hearing hints that one of 
these days someone may 
develop a version which is 
usable on a microcomputer, 
but I haven't seen any 
announcements yet. 

While FORTRAN was 
developed for scientific use, 
COBOL was developed for 
business use. It's the language 
used by the U.S. government 
for a lot of their stuff, so it's 
got a pretty wide circulation. 
Needless to say^ many 
businesses use it, too. From 

the little work I've done with 
it myself J it seems that you 
spend most of your time 
defining what your printout 
is going to look like and what 
the information which you 
feed into the thing is going to 
look like (the jargon for this 
is format definition). It also 
takes lots more memory than 
one would probably want to 
pay for In a microcomputer - 



BASIC . . , was designed for people who 
know nothing about computers, but who 
want to use them. 



lot more than simply crunch 
numbers. Moreover, since it's 
such a popular language, 
there are who-knows-how- 
many programs written (and 
sometimes published) in it, 
which makes it much easier 
to solve a given problem 
(since you can frequently just 
type in a canned program). 
The same structural problems 
encountered In BASIC are 
part of FORTRAN, but these 
have already been covered. 
Perhaps more important for 
anyone who wanted to use 
FORTRAN on a microcom- 



unless he wanted to do sub- 
contracting for the govern- 
ment. 

Up until the early 1960s, 
most computers were eitha^ 
scientific- or business- 
oriented, and a machine 
which was designed for one 
didn't usually work too well 
for the other. Then IBM 
started making their general 
purpose machines, and most 
other people followed suit* 
At about the same lime, 
people started to worry about 
a general purpose computer 
language. A number were 



developed, of which my 
favorite (just for the name) is 

MAD (Michigan Algorithmic 
Decoder) which was brought 
to us by the folks at the 
University of Michigan Com- 
puting Center. Then IBM got 
into the act, and, lo and 
behold, out popped PL/1 
(Programming Language 
One). The best description 
that ! can think of is that it 
was designed to out-fortran 
FORTRAN and to out-cobol 
COBOL all at the same time. 
It does a pretty good job of 
it, too, Vm always amazed at 
all of the nice thin^ you can 
do with PL/1; to use the 
computerese phrase, it has 
more bells and whistles (extra 
options) than you can shake a 
stick at. Unfortunately, it 
also uses more memory than 
you can shake a slick at, 
which makes it too expensive 
for microcomputer use {or 
even timesharing use if you 
have to watch your costs). 
But never fear, one of these 
days we may be seeing a 
scaled down version of PL/1 
(called PL/M) which keeps a 
lot of the nice features 
without taking up wore 
memory than most of us 
mere taxpayers can afford. 
To give an example of the 
sort of nice thing the 
language can do (among 
others), it lets you write a 
simple either/or statement {if 
this is true, do one thing j 
otherwise do this other 
thing), whereas to do that in 
most other languages you 
have to play hopscotch with 
the line numbers. In short, 
PL/1 is a great language, and 
if a cheap compiler ever 
comes out^ I hope I own the 
microcomputer it's written 
for! 

Another new language, 
again by IBM, is APL. 1 will 
confess here and now that 
IVe never used it, so what I 
say is taken from what people 
who have used it have told 
me. This is a very powerful 
language; it can do in one line 
what most other languages 
require five or more lo do. It 




is not yet widely used; unle^ 
I'm mistaken (which is quite 
possibte) IBM h the only 
company which makes com- 
pilers for it. It is, however, 
designed for the sort of sit- 
down-at-your-computer use 
that most hobby users 
probably have in mind. And 
good news! It's available for a 
microcomputer. The bad 
news rs that said machine Is 
the IBM 5100 and it runs 
about I Ok — and those are 
ktlobucks^ not kilobytes. 
Anyway, the scuttlebutt has 
it that APL is one of the 
languages to watch, so keep 
your eyes peeled. 

I mentioned a while back 
that, in addition to the 
general purpose languages Tve 
discussed so far, there are 
quite a few special purpose 
ones. For a hobby user {or 
would-be uso') these aren't 
too important, but just to be 
more or less complete Til 
mention a few which are 
good with which to impress 
people (besides being good to 



know about if you tend to be 
around computer hot dogs 
who like to talk about such 
things). There is RPG, which 
is a Report Generating 
language, and therefore much 
used for business and that 
sort of computing, ITien 
there are several languages 
used to wrfte simulations. (A 
simulation is like a computer 



SPITBOL and so forth. 
Finally, there is at least one 
language used to design elec- 
tronic circuits — unfortun- 
ately all my electrical engi- 
neering friends seem to be 
able to tell me is that it exists 
and Professor Zilch men- 
tioned it. 

As a brief review, one 
needs some sort of language 



FORTRAN , , . does things in harder 
more roundabout ways than some of the 
newer languages, like PL/1. 



game except people take it 

seriously. Come to think of 
it, I know a couple of people 
who take the Star Trek game 
seriously, but we'll ignore 
that.) These languages are 
things like GASP, GPSS and 
so forth. There are a fair 
number of languages used for 
crunching words instead of 
numbers - SNOBOL, 



to give a computer instruc- 
tions. You can operate on the 
machine's level (called 
machine language) and feed it 
ones and zeros. Or, you can 
stay on the machine's logical 
level but use decimal numbers 
and abbreviated commands. 
This is called an assembler 
language, and requires a 
separate program for transla- 



tion into machine language. 
Finally, you can use a com- 
bination of human logic and 
normal words and symbols, 
which is called a high level 
language. This requires a pro- 
gram to translate it into 
machine language again, and 
such a program is called a 
compiler. The principal 
advantages of high level 
languages are that they are 
easy to learn, easy to use, and 
are the same for any machine. 
They are not nearly so effi- 
cient as assembler language 
from the computer's point of 
view, but they are much wore 
efficient from our point of 
view — and that's usually 
what counts. ■ 



References 

1. BASfC AJbrecht, Finkal and 
Brown, Wiley & Sons, 1973, 

2. Digital Computing, FORTRAN 
tV, WAT f IV, and MTS, Carn- 
ahan and Wilkes. Ctiemical Engi* 
neering Dept., University of 
Michigan, 1973. 

3. High Speed Data Processing^ 
Gotlieb Si Hume. McGraw-Hill, 
1958. 



SP 600 - Still the great all time general coverage receiver. 



540 kHz to 54 MHz. Selectivity down to 200 Hz. Xtal 
calibrator, noise limiter - double conversion. The perfect 
SWL receiver. A great 2nd receiver for the shack, A very 
limited quantity completely overhauled and guaranteed . . . 
HURRY ! HURRY ! Onlv $300.00, 

Mr' 







AN COM maintains an extensive inventory of military and commercial 
publications. We continuously research methods of utilizing surplus 
Write or call stating your requirements- 



equipment and 
equipment. 




ELECTRONIC CORP. 



5521 Cleon Avenue, No. Hollywood, Ca. 91601 



213-769-5518 



73 





from page 8 

you KNOW yau havt* the signal right 
on the nose. 

I'm playing around with a phase 

shift TTY converter which seems to 

promise qresK things. I wonder if you 

would have any interest? (Of course 

. Wayne J 

New subject: mrnhoomputers 
(micro if the shoe fits). I think one of 
the great probtems facing the Mould- 
be computer hobbyists is that the 
manufactufers, in their ads and rnore 
atnazingly in their littratune, seem to 
be quite reluctant about two ihirtgs: 
one, a simple block diagram showing 
!he necessary basic cards/modules and 
how they plug togethef; and two, a 
simple format of how a program on 
Lheir machine looks and what the 
owner has to do to make the thing 
work. Hiding these things, either on 
purpose or by oversight, may prevent 
many vrould-be's from getting into the 
act. 

I have been fooling around with 
systems analysis and programing com- 
puters for quite a few moons now« 
particuEaiiv as they retate to oommun- 
ications services and lacilities. arKi It 
seems to me that the manufacturers 
are ifiissing a good selling tool by not 
explaining, in Englis^t, what's Qoing to 
happen when he does this and that. 
(Vone of the literature that I have 
received (and Tve got them all) from 
any of the manufacturers has given 
me the slightest clue as to what to 
expect or Indeed what to buy to do 
such and -such. 

Eugene F, Locke W2SKK 
Sea CI ill NY 



UPKEEPING 

t think; you've got the best maga- 
zine in ham radio — and hotibv 
electronics in genera* too. since £t 
vrent out= Keep up the good work. 

Eric WiMiams 
Scotts Valley C A 



FAR OUT 

I almost had a heart attack today 
(and I'm only 19). I received my 
PhAarch issue of 73* None of tfie other 
ham magazines fias gotten here that 
quick , ., FAR OUTfil Keep up the 
iniereaing articles. I hope sometime 
in tf^ future I see articles on buildirtg 
ATV stations and more on mitxopro- 
cessors (I'm getting imeresiedar>d can 
u^ soTTie infoK 

Bob Brlison WA2TXY/AA2TXV 

Westf ield NJ 



you priiiL t;v 



SMOB8iSH? 

I guess you talked ma into becom- 
irkg an amateur. I've been reading 7J 
for a couple of months now ard I 
final ly decided to take the steps 
necessary lo acquire my ticket. En 
closed Is ST 3.95 for a fytl set of the 
code tapes. As an amateur, you have a 
refreshing ouikx>k on the CBer and 
his or her potential as an amateur 
recruit. This, in addition to ttie fine 
an ides in itie magazine, is the reason 
why you got my tT^emy bucks for a 3 
year subscription to 73^ 

I have been servicing citizens band 
and amaiBur pear for a couple of years 
now, and the snobbish outlook of 
amaieurs has kept me out of amateur 
radio until now* There must be more 
amateurs in tfils country with your 
outlook on the CBer. and I have 
decided to take the time io find some 
of them. 

Thanks for the fine magazine, 

Mtcfiael L. Aber 
VaJlejo CA 



ILL WINDS 

I fBcently swbscnbed to your maga- 
zine as a result of again becoming 
interested in ham radio. Although I 
have been active in years past (for- 
merly W8LST, KR60X and BA2TY). 
I have not been active since my last 
license expired in 1963. 

I jusl received the March issue and 
as I was scanning through it, the 
article, ''Infierit the Wind/' came to 
my attention. 

The first trme I read the author's 
instruct mns for building the anemo- 
meter, particularly his lo^ic used in 
calculating the 2.80" radius for 
loc^ling the 1/8*' hols in ttie disk 
assembly, I couldn't believe that I was 
intefpreiing his logic correctly. After 
reading ii a second time, I concluded 
that he eitfier goofed in his line of 
reason mg or he is crying to test for 
reader response. 

He indicates that the 1/8" hole 
should be drilled in the disk at a 
distance of 2.8" from the canter. The 
only purpose for the hole, as I see it 
is to allow a pulse of light to reach the 
photoelectric device once per revolu- 
tion of the disk, and this can be done 
whether the fxjle is Z8*' or 2.8 feet 
(or TOO fee! J from the center^ as long 
as the photoelectric device is ahgned 
at the same distance to match tf^ hole 
when it oomes around. 

In order to receive one pulse of 
light per second per mph of wtnd 
velocity, tt win be necessary to space 
the cupi on the anemometer cup 



assembly property from the center of 
rotation so that the circumference 
fsrresponds lo the distance thai the 
wind molecules travel in one second at 
one mph (jBSuming 100 percent etfi 
ciencyL and I will accept his calcula- 
tion of 2.80'* for this radius. 

Although I haven't buitt this 
anemometer, it seems that 2.80" 
might be a little stiort to obtain good 
efficiency, l would suggest therefore, 
that the radius figure be doubled or 
tripled to overcome this possible 
drawback. 

Doubiing or tripling the radius 
would of course reduce the revolu- 
tions per second by T/2 or 1/3 respec- 
tively. This could be offset by drilling 
2 fwles or 3 holes, respectively, 
equally spaced around the disk at 
whatever radius the builder decided 
was most desirable. This would sttll 
allow the photoelectric device to lee 
one pulse per second per mph of wind 
velocity. 

Gene W. Creighton 
Findlay OH 



FOREVER GRATEFUL 

I am a tolerant ham wife. I don't 
make plans for Sundays when there 
are hamfests, I don't complain when ! 
sm "widowed" on contest weekends. 
I have accompanied my hustiand to 
several conventions when nobody else 
could go. I read 73 (at least the 
"Letters" section — I understand 
iliatlll. 1 even put up vwith being 
called an XYL when I'm not really 
aire whether the X means Tm no 
Longer young or no longer a Jadyl But 
rraw I have a request of all of the 
hams, and as it probably is not unique 
with me, I feel it bears voicing. 

OM, when you come to eyeball 
with my husband or to work on 
equipment, please leave your toddlers 
at home. I will carry coffee or beer to 
the shack. I will hold wires while you 
solder. But please, pfease don't ask me 
to babysit, If I weren't at home, you 
would be responsible for your child's 
welfare. You know fiow impervious 
you are to your surroundings when 
you gel involved in a project. Would 
you warn your child loose in your 
shack If such a time? 1 know your 
wife deserves a br@k, but not at my 
expense. So I promise you, I won't let 
my husband bring our chitd to your 
ftouse if you don't bring yours to my 
house. Give your wife her break some 
other time, and I will be forever 
grateful. 

The X'babysttter 
(Name and address submitted) 



THE METRIC SCOOP 



m 






APS TOO. DREAMS (?) 



Mahalo, keep up tfie good work. I 
look for tti© 73 for days before it 
arrives. arwJ it disturbs my sleeping 
habits until I read it cover to cover 
(ads too, dreamsK 

Everett W. Curry, Jr. 

K6VGL/KH6 

Honolulu HI 



Why don't you scoop QST by being 
the first to go the metric paper size? 
Eventually, why not now? 

Ken Lewis WA4QHZ 
Albany G A 

Excettent ideal Behold ... 73 Maga^ 
zine, the first of (he 2t ^ 27,5 cm 
magaaimu! — Wayne. 



EERIE 

Thank you for the special surplus 
section in your March issue. To a 
"surplus hound" like me it was 
interesting reddtnc|. Keep it up! 

J. K. Bach, who wrote tfie s^ticfe 
titled. "Adventure/* might be 
interested in some Hiformation con- 
cerning tfie calcufator fw bought. He 
has a Uoyds Accumsth^ 60^ 1 1 sold 
for about S60 to S85 new and was 
discontinued two years ago. The unit 
was built by North American Rock 
well (this is where I came in contact 
with it} and probably assembled in 
Mexico, Readers who have this calcu- 
lator might be abfe to obtain replace- 
ment parts by writing Lloyds' service 
department located in Compton. Cali 
fornia. 1 must say it is an eerie feefing 
to read about a product you have 
worked with since its design stages 
deso'ibed by someone with pinpoint 
accuracy wtio doesn't know what f>e 

Gary McCiellan 

Project Engineer 

Gary E^ctronics Co. 

La Habra CA 



WORTH A TRY 

The following is a little tip that I've 
"re-invented" and which might be of 
some interest lo your readers. At first 
1 was somewhiaf puzzled by tfie 
occasional "jreroing'" of my distal 
LED wristwatch for no apparent 
re^on. 1 thought about intermittent 
intemaJ connections {ugh), strong rf 
fields, etc., but then hnally narrowed 
it down to simply a static charge 
build-up on the red plastic faceplaie 
of the watch tisetf. Going back 
tfirough my memory bank, I rem em 
bered the sure-fire cure for static 
build-up on plastic meter faces used 
by hams all over for the last dozen or 
so years and my problem was solved. 
In case you've forgotten, the cure 
involves merely placing a couple of 
drops of liquid deier^m (Ivory in my 
case) on the faceplate, spreading it 
around with i flngef-tip, letting it 
stand lor a minute or so. and finally 
wiping the bulk of the detertieni off, 
A thtn film of detergent seems to 
remain behind to protect against 
further butld^up for some time, but it 
is a good idea to re-coat ttie facaplate 
every couple of weeks, especially 
during tfie cold, dry winter months. 
Mo one can guarantee that this pro- 



74 



cedure will work for all digital 
watches, but K certain! v is worth a try 
before packing rt off to the manufac- 
turer for repair. 

David F. Mill&r K9POX 



CREDIT LIMARC 



At 3 hobby exposition on Sunday 
afternoon, January 25th, sponsored 
by the Plainedge Public Library in 
Ma^sapequa, N.Y.. members of the 
LIMARC ATV technical groyp gave 
an on -The air demonstration of ama- 
teur television two way transmissiort 
between W2WLS/2 and W2NIP. Ama- 
teur color TV irammissions were also 
demon stra ted as was a complete solid 
state ATV transrnitter developed by 
W2TRP. Other participating AT Vers 
were WA2APJ, W22UC, WA2FHF 
and W2KPQ. 

Also shown were exhibits of slow 
scan TV, repeater operation, and an 
exhibit of a precision radio controlled 
boaibuiftby WB2AQM. 

K20PF, emergency coordinator for 
the town of Oyster Bay. demonstrated 
traffic harvdling during the simulated 
emerger\cv test on this date. Other 
groups who joined in with exhibits 
were the Wantagh Radio Cfub. the 
Farmingdaie Radio Club and the Long 
Island DX Association repres^ted by 
WA2BVU and W2AWK. Amateur 
radio in the scouting movement was 



ably handled by WB2yYV. Outside 
the library a mobile van containing an 
"Oscar" Siteitice terminal was manned 
and demonstrated by K2REC and 
WB2AMX. 

The show was very weJ( attended 
by many people who were dravm In 
by ne^vspaper. cable TV and word of 
mouth advertising over local repeaters. 

K2UQ, LIMARC president, and 
WA2WKV, who organized the event 
for LIMARC, feel that cooperative 
effort by many radio groups such m 
this can bring much positive interest 
and credit to ttie amateor radio image, 

Ed Filter W2KPa 
LIMARC 



THE WHITE HOUSE? 



] 



Just a short note to compliment 
you on the mag. Arrival of 73 is the 
high point of my month. Unlike all 
other mags, every article in 73 is 
usually of interest to me rather than 
just 5 pages or so out of 150 pages. I 
am fairly knowledgeable in the field 
but I can't make heads or tails out of 
most of the stuff in OST and the 
ottiers. Too bad Hot fine went west — 
HR Report »s reaUy playing it up big 
iri their adi. 

It sounds like the gang at 73 really 
swirls. Yoy talk abcHit things up there 
a lot and it has aroused the curiosity 
of myself and probably k>ts of others. 




Ed Pflhr W2KP0, UMARC ATV Chairman, (^icussJng ATV details witn Lm 
Srascho\fler^ president of North Hifis Bkctronim Corp. WA2FHF i$ in 
foreground teft and W82DJK is in imck ground right. 




How about a piece in 7J with pictures 
of the gang, pix of the 73 bidg, 
antennas, rigs, SJrrounding country- 
side* etc? We all would be very 
iftterested in this — sort of like a tour 
of the White House or somethirtg. 

Well — thanx for the consfderairon. 
Maybe one man's opinion might be 
worth something. Really enjoy 73 — 
Star Trek communicators and all that. 

Steve Uhrig WA3SWS 

Columbia MD 



UNLOCKING PLL'S 

I wish to bring to the att^tion of 
Dr. Thomas A. Reilly and Calvin 
McCarthy, and any interested readers, 
that the book Phase Locked Loop 
Systems, published by Motorola and 
reviewed in the Nov/Oec 1975 Issue of 
73 under the heading "For Your Eyes 
OnlyH'' is no longer available. 

J m mediately after reading the 
review I sent off a check to Motorola 
for a copy of this book. I was ex- 
tremely disappointed today to have it 
returned with a note that it is no 
lorvger available. For some time now I 
have been trying to obtain a book 
dealing with PLL^, but so far without 
success, if there are any readers/hams 
out there who may have a copy of this 
book and are prepared to pan with it, 
please let me know for how much and 
I will remit the necesi^ry amount. I 



would also appreciate knowing of any 
other publications dealing with PLLs 
that may be available. 

Finally, let me compliment W0 AC R 
on his really great scope article titled 
"Eyes for Your Shack" in ihe same 
issue. It was really quite an achieve- 
ment and a number of friends in this 
part of the world are considering 
duplicating it eithi^ in pan or in its 
entirety. 

Jofwi C. Webster VP2DN 

62, Milnef Hall 

University of tiie W.L 

St. Augustine 

Trinidad W.L 



SEAW 

I thought I'd drop you another line 
on the status of CW in the U.S. Army, 
Just last year, the required fevel of 
proficiency for all CW radio operators 
(except for high speed intercept oper- 
ators) dropped from IS wpm to 10 
wpm. It looks like in this day of 
microwave, tropo scatter, and satellite 
communications, the need for HF 
communications (which is about the 
only place CW has a real advanta^ey is 
diminishing rapidly. 

In contrast, my unit (Spedaf 
Forces, or the ^'Green Berets"}, who 
use HF almost exclusively, has upped 



Continued on page fOO 




PN/ dettan K2LfO, LIMARC president, and George G/ack WA2WKV, 
LIMARC exhibit chairman. L IMA RC A TV poster in background. 




Jay Roseniweig WA2APJ, LIMARC vice president, demonstrates live ATV link. 



Scoutmaster Larry Weil WB2Yyv mam the "Ham Radio in Scouting" exhibit 
at the Lf MARC showing. 



' 75 






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Tapes 
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Power Supplies 
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Computer Boards 

Reproducing Punch 
AC Voltage Stabilizer 



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a 




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Dit0 to updating our computer installation we are offering a majority of our Univac computer systems at 
unbelievable prices. Manuals furnished. Many items offered by the pound. Most equipment taken out of servfce in 
working condition. 



Examples: 



FIRST COME FIRST SERVE! 

Computer tapes - S2.00 ea. 

Interfiling reproducing punch - $.10 per lb. 

Key punches - $.25 per lb. 

Electronic counting sorter - $ JO per lb, 

600 line per minute high speed printer - $,50 per lb 

Write for detailed list and prices to: 




DepL 25 Pimenio IN 47S66 

Telephone SI 2-49 5-6 55 5 



M 



76 



Dick Whipple 

305 Clemson Drive 

Tyler TX 75 701 



and 



John Arnold W5CUD 
RFD 4, Box 52-A 
Tyler TX 75701 



A Very Cheap I/O — the Model 15 



Contrary to the opinion 
expressed often in com- 
puter hobbyist publications, 
Baudot Is not dead! It is alive 
and well^ especially in Tyler, 
Texas! Frankly, I am glad I 
learned years ago not to 
believe everything i find in 
print. If I had, my Model 15 
Teletype® would not be 
speaking BASIC today. I 
want to make it clear at the 
outset that this article is not 
intended to foster a Baudot/ 
ASCII split among computer 
hobbyists. Nor is it written to 
argue the relative merits of 
one system over the other. I 
wish simply to demonstrate 
that a Baudot machine can be 
made an effective and useful 
hard copy peripheral in a 
hobby computer system. 

Permit me to digress a 
moment from the main sub- 
ject — Baudot — to comment 
in a more general way on 
these people we call 
*'hobbyIsts." Although they 
come in many different 
varieties depending on 
interest and ability^ there 
seems to be a common thread 
running between them: the 
need to be creative with their 
hands, heads, or both. For 
instance J there can be no 
greater pleasure for an elec- 
tronic hobbyist than to sit 

back and watch his junk box 
creation perform like its 
"store bought" counterpart. 
At that moment he feels a 
sense of accomplishment 
unobtainable in many other 
pursuits of life. This *'make 
do with what you have*' 
philosophy is a reflection of 
the spirit that has brought 



man to his stately position 
among the world^s lesser 
creatures. The hobbyist has 
the opportunity to foster this 
spirit each time he digs into 
his junk box for a new 
project. Unless you think I 
am only talking about an 
electronic junk box, let me 
remind you that a 16K word 
memory filled with NOPs is 
in a sense a junk box as well! 

What does ail this philoso- 
phical wandering have to do 
with Baudot? Simply this: 
There are people who say 
Baudot is obsolete and Tele- 
types that speak it are junk. 
Now, can^t you see the eyes 
of some hobbyist light up 
when the word '*junk" Is 
mentioned? The very word 
carries with it a challenge he 
cannot resist. Out to the 
storeroom he goes to retrieve 
his old Model 1 5, The re- 
newing of the hobbyist spirit 
has begun! There he goes . . . 
Watch him ... Next stop 
Baudot BASIC! 

About six months ago, a 
friend and I were taking just 
such a challenge. We have 
made quite a lot of progress 
since then. In our present 
state of excitement we want 
to share some of the know- 
ledge gained and lessons 



learned. We hope our success 
will encourage some "junk 
box digging" by readers of 
73. 

Getting Started 

The best place to begin is 
in the pages of a book on 
Baudot Teletypes. One gbbd 
choice IS Wayne Green's 



RTTY Handbook (Tab 
Books). Learn the theory of 
t e I e p rinter operation and 
become familiar with the 
different machines available. 
Next, begin your search 
for a machine. This will 
probably require some foot- 
work and a little time. If you 
live close to a large city start 



■b" 



ADJUST FOB- 60itifl 

yfi 13+ 1 2D VDC 



J 



KEVSOAftO 

— O P D 



^in 



f av 



TTL L^Vfl. ^^ /K\ 
DftlVE V (^WVH^ — H J 

<3 jOAWLTs Vx^y; 




PRINTER MAGllETS 



LOCAL ~LI;*(E SWITCH 
HOM SHQRTiyfB TYPE 
SHO*N IS LOCAL WSITUaM 



Fig, h Teletype interface Qircmt: Mode! 15 or similan 



IK 



KETfBOAffO 



"?4DI 



.r"^ 



TO Jii Q 




TO 
*TELETifPE"A" 



PWR 



Fig, Z Computer Interface for software I/O. fahels reflect 
Altair 8800 bus. Points A and B refer to Fig, L All /Cs are 
7400 series — low power except 7401. 



TELETYPE 
SPEED 


11 


10 


9 


S 


7 


PRESET COUNT 
6 5 4 


3 


2 


1 





60 wpm 


Q 


1 





1 





1 











1 


1 





66 wpm 





1 


f 














1 


1 





1 





75 wpm 





1 


1 


1 





1 


1 





1 


1 








100 wpm 


1 


Q 





1 


1 








1 








1 






Table 1. Baud rate set up for Baudot Teletypes on Altair 8800 serial IjO boards. 



77 



U 



by looking in the yellow 
pages under junk dealers and 
electronic surplus houses* 
Make a few phone calls, ask 
questions, and follow leads. 
There are mail order com- 
panies that have teleprinter 



LABEL 



IWUT 



L0OP1 



OCTAL 

ADO R ESS 



Law- 



LO0P2 



(xni»UT 



LCKIP3 



TMOOT 
L00P4 



equipment. Check the back 
pages and ctassificd ads of 
amateur and computer 
hobbyist magazines. Write a 
few inquiries and get quota* 
lions - ask for the specific 
machine you want. Get in 



touch with local radio ama- 
teurs and see if they can help. 
Hams generaJly have a good 
attitude toward hobbyists of 
other persuasions and go out 
of their way to help. You 
might find a ham with a spare 



OCTAL 



000 


001 


001 


000 


ooz 


DOS 


003 


333 


004 


376 


tm 


037 


mm 


332 


007 


003 


010 


000 


oil 


026 


013 


030 


013 


31 B 


014 


110 


015 


000 


Olfi 


333 


017 


370 


020 


037 


021 


171 


022 


037 


023 


117 


024 


026 


02S 


020 


029 


315 


mr 


110 


030 


000 


031 


005 


032 


307 


033 


016 


034 


UIHJ 


0^ 


171 


03S 


017 


037 


017 


040 


017 


Ml 


311 


042 


OOi 


043 


006 


044 


007 


om 


117 


04S 


227 


047 


323 


OGO 


376 


0S1 


026 


0E2 


020 


0&3 


315 


064 


110 


0B5 


000 


0S€ 


171 


0S7 


017 


0«0 


117 


0€1 


346 


0«2 


D01 


063 


323 


Ofli 


376 


OOB 


026 


OM 


020 


0«7 


31£ 


070 


110 


071 


ooo 


072 


0(B 


073 


302 


074 


066 


07S 


000 


076 


076 


077 


001 


100 


323 


101 


376 


102 


026 


103 


030 


104 


315 


106 


110 


106 


000 


107 


31t 


110 


076 


111 


XXX 


112 


Qfm 


113 


302 


114 


112 


11& 


000 


116 


02S 


n? 


302 


120 


110 


121 


000 


IS 


3t1 



(MNEMONIC 



LXI B 



IN 

RAR 
JPG 

LOOPIlL^ 
LOOPIIH} 
MUI D 

CAL 

TlVIOUTal 

TIWOUTIHJ 



COMMENTS 



ZERO C: COUNT IN B 



LOOK FOR START PULSE 



JUMP BACK IF NO START 



SET FOR 1H TIME UNITS 



CALL TIME OUT ROUTINE 



COLLECT 5 DATA PULSUS INTO C 



RAR 




MOV A. C 




RAR 




MOV C. A 


SAVE A 


MUID 


SET FOR 1 TIME UNIT 


CAL 


CALL TIME OUT ROUTINE 


TMOUTfLl 




TMOUTiHt 




DCKB 


CHECK COUNT 


JNZ 


JUMP SACK IF NOT FlNl£H£0 


LOOP2(LJ 




LOOP2CH} 




MOV A. C 


RETRIEVE A 


RKC 


ADJUST A TO PLACE SAUDOT IN 


RHC 


LQVUER S BITS 


RRC 




fl£T 


END INPUT ROUTINE 


I4UI& 


COUNT IN B 


RLC 




MOVC.A 


$AV€A 


SUB A 


CLEAR A 


OUT 


OUTPUT SI ART PULSE 


MUIO 


SET FOR 1 TIME UNIT 


CAL 


CALL TIIWE OUT ROUTINE 


TMOUT{LJ 




TViOUTjHj 




MOV A, C 




RRC 




MOVC, A 




ANI 


MASK OFF ALL eUTi BIT 


OUT 


OUIPUT DATA PULSES- 5 IN ALI 


MUID 


SET FOR 1 TIME UNIT 


CAL 


CALL TIMEOUT ROUTINE 


TliOUTfLl 




THOUTmt 




OCR 9 


CHECK COUNT 


JNZ 


JUMP SACK If NOT FlNiSHEO 


LDOP3(U 




ux»2m\ 




1MJIA 




OUT 


OUTPUT STOP PULSE 


MUID 


SET FOR 1^ TIME UNITS 


CAL 


CALL TIME OUT ROUTINE 


IMOUTtLJ 




TMOUTtHJ 




RET 




MU1 A 


ACUU6T TIME DELAY 




170a *«"■ GO wpm: t3B tot IB wpm 


DRCA 


IMITS STATIC MEMORY TESTED 




VALUES! 


JNZ 


JUMP OACK tF NOT FINISHED 


LOOP41LJ 




LO0P4tH> 




DCRD 




JNZ 


JUMP BACK IF NOT FINISHED 


TMOUT(L) 




TMOuTtHJ 




R£T 





Fig, 2(a). Serial f/O: Software technique for Fig. 2 



M 



Teletype that he would be 
willing to loan out until you 
can get your own* 

Give Western Union and 
Bell Teiephone a call. If you 
can get through to the right 
people you may have a 
chance of getting a free 
machine. I have heard of this 
approach yielding success 
more than once. In these 
inquiries be sure to emphasize 
the *Vhobby*' nature of your 
t merest f Above all don't get 
disappointed and give up too 
soon. There are thousands of 
these machines out there — 
probably one mih your name 
on itl 

The Care and Feeding of a 
Model 15 (or Similar) 

As the owner of a Baudot 
Teletype you should take 
some pride in your new 
possession. Over the years the 
Model 1 5 Teletype has gained 
an excellent reputation 
among people who appreciate 
well -engineered mechanical 
devices. Most of its moving 
parts are made of case- 
hardened steeL When a part 
does wear there is generally 
an adjustment somewhere to 
take up the slack, If you can 
find a maintenance manual, 
get it and use it. Your efforts 
will pay off In many years of 
reliable service. I have often 
heard Model 1 5 owners say 
not to worry with cleaning 
the working parts — the 
worse it looks the smoother ft 
operates, A friend has a 
Model 15 with several mure 
layers of dirt and grease than 
mine. Not only does his key- 
board have a lighter touch 
but his printer is several 
decibels quieter! Remember 
to keep machine oil in the 
cups and on the clutch felts. 
With reasonable care your 
machine should serve you 
well for years to come. 

The Interfacing Problem: At 
the Teletype End 

Normally the Teletype will 
have two connecting cables: 
one for send (the keyboard) 
and the other for receive 
(printer magnet). For testing 



78 



purposes the two can be 
series-connected with a power 
supply and current limiting 
resistor. Connected in this 
way the machine will type to 
itself. Teletype users call this 
"local loop" operation. For 
computer use the send and 
receive cables must be con- 
nected separately. Fig. 1 
shows a transistorized switch- 
ing circuit that provides the 
necessary TTL level signals 
for a computer interface. 

The following notes refer 
to Fig. 1 : 

1. The use of a high voltage 
supply (100 to 120 volts) is 
recommended since it pro- 
vides the simplest and most 
r^^liable operation. Of course^ 
the driver transistor must be a 
high voltage type similar to 
the one shown, 

2. Make certain that the 
local-line switch is a non- 
shortlng (break-befo re-make) 
type. 1 20 volts is not a TTL 
level 1 A telephone type lever 
switch is IdeaL 

3. The printer magnets 
(usually there are two 
mounted side by side) can be 
connected in series or 
pafafleL The circuit showri 
assumes a parallel connection. 
Adjust the slide on the power 
resistor for 60 mA in the 
magnet circuit. 

A. Notice that in the local 
position the keyboard con- 
tacts are switching the full 60 
mA at 120 volts. The contact 
arcing seems to do wonders 
for qjeaning up noise 
problems in the keyboard. In 
the line position, the key- 
board is switching to ground 
and the printer wil! accept 
TTL logic levels. 
5, Make abso/utefy certain 
that the Teletype and all 
computer circuits share a 
good ground system. In fact, 
connect the Teletype chassis 
to the computer ground with 
a separate heavy wire. We 
have experienced ac tran- 
sients on interface lines when 
the ground connection on the 
Teletype was inadvertently 
broken. On one occasion we 
lost some TTL in our Altair 
during such an occurrence. 



LOWER CASE 


5 LEVEL 


6 LEVEL 


UPPER CASE 


5 LEVEL 


6 LEVEL 


A 


003 


003 


^^ 


003 


043 


B 


031 


031 


? 


031 


07t 


C 


016 


016 


4 


016 


056 





Oil 


Oil 


$ 


011 


051 


E 


001 


001 


3 


001 


041 


F 


D15 


015 


\ 


015 


055 


G 


032 


032 


8i 


032 


072 


H 


024 


024 


■# 


024 


064 


r 


006 


006 


8 


006 


046 


J 


013 


013 


Bell 


013 


Q53 


K 


017 


017 


1 


017 


057 


L 


022 


022 


1 


022 


062 


M 


034 


034 


« 


034 


074 


N 


014 


014 


f 


014 


054 


O 


030 


030 


9 


030 


070 


P 


026 


026 





026 


066 


Q 


027 


027 


1 


027 


067 


R 


012 


012 


4 


012 


052 


S 


OOB 


005 


f 


005 


0^ 


T 


020 


020 


5 


020 


060 


U 


007 


007 


7 


007 


047 


V 


036 


036 


* 


036 


076 


W 


023 


023 


2 


023 


063 


X 


035 


035 


1 


035 


075 


Y 


02S 


025 


6 


025 


065 


Z 


021 


021 


tt 


021 


061 


CR 


010 


010 


CR 


010 


050 


LF 


002 


002 


LF 


002 


042 


SP 


004 


004 


SP 


004 


044 


BLNK 


000 


000 


BLNK 


000 


040 


FGS 


033 


033 


FGS 


033 


073 


LTR 


037 


037 


LTR 


037 


077 



The Interfacing Problem: At 
the Computer End 

There are several schemes 
available to perform the serial 
input/output function at the 
computer; A UART (Uni- 
versal Asynchronous Receiver 
Transmitter) is readily 
adaptable to five level Baudot 
code. The UART represents a 
hardware solution to the 
problem. The serial /parallel 
conversion can also be 
handled by computer soft- 
ware. This simplifies the hard- 
ware requirement but ties up 
the CPU during input/output 
operation. The circuit in Fig. 
2 and the accompanying soft- 
ware listing will illustrate this 
latter technique as applied in 
an Altair 8800 system. 

Although the software I/O 
system is probably not a good 
long-term solution to your 
i/0 needs, it does offer a 
quick and simple approach to 
getting ypur Tel^jype on-line. 
Fig, 2 IS very similar to the 
interface circuitry necessary 
for a cassette interface of the 
Suding type- If you later 
change your I/O to a UART 



Table 2. Baudot-octa! conversion. 

type, you can use this circuit 
to build up a cassette Inter- 
face. 

To check out the software 
I/O, make the following test: 

1. At a memory location 
above the I/O routines^ load a 
main program similar to: 

LXI SP, LOOP + 10 
LOOP CALL INPUT 

CALL OUTPUT 
JMP LOOP 

2. EXAMINE the starting 
location of the main program 
and begin execution, 

3. The printer should now 
echo keyboard entries- 

In our Altair 8800 system 
we have used several home 
brew I/O interfaces with 
success. Our original circuit 
followed in design the "Basic 
Stunt Box" on page 299 of 
RTTY Handbook. This 
circuit was modified and 
improved through several 
generations. Most recently we 
have used a MITS SIOC inter- 
face board with a few simple 
modifications (see below). 
The MITS board is UART- 
basedj with a software con- 
trolled interrupt scheme we 



have found very useful. 
Processor Technology's board 
is currently being used by 
Frank Corlett WA5BNK with 
his Altair 8800 and a Model 
28. After a great deal of 
experimenting, we have little 
doubt that a UART-based I/O 
interface is best. 

The MITS SIOC board was 
originally intended for use 



M5V 



I5K 




14 — •^^-*' POINT *B* OF CIRCUIT i 



fl70 



|— » NO! 



NOT CONNECTED 



• NOT CONHECTEO 




■^ —^ POINT V Qf CliRCIJJT T 



J 



/7? 



ftiTAIR GROUND 



TEUETTPE 
GROUNP 



Fig. 3. Telelype drive circuits 
for M ITS SIQQiriter face with 
modification for connection 
to a Model 7 5 Teletype. 



79 



M 



with a Model 33 Teletype. To 
use it with a Model 1 5 or 
similar machine, make the 
modifications shown in Fig. 
3. 

In preparing the MITS 
board, the number of stop 
bits must be selected. The 
five level Baudot code con- 
sists of a start, stop and five 
coded data pulses. The start 
and data pulses are 22 ms 
each (60 word per minute 
maehines) while the stop is 
31 ms, about V/i times the 
others. Theoretically, the 
stop pulse generated by the 
serial I/O circuit should be 
V/i times the length of the 
start and data pulses. The 
MITS SIOC board has pro- 
vision for 1 or 2 stop pulses 
only. Our experience has 
shown that both choices 
work satisfactorily. One stop 
pulse types a little faster than 
normal, 2 stop pulses a little 
slower- We have used the 1 
stop bit set up for some time 
without any problems. A 
UART is available that pro- 



vides the correct 1 Vi stop bits 
but we don't believe you 
need to be too concerned 
about getting one. 

As you implement a 
Baudot system J knowledge of 
the Baud rate will be re- 
quired. For instance, the 
MITS serial board instruc- 
tions do not provide directly 
the Baud rate hookup for a 
60 wpm Baudot machine. 
After a little head scratching 
we were able to figure out the 
circuit connections. For thos^ 
contemplating a MITS 
board, Table \ gives the 
necessary data for strapping 
the Baud rate counters. If 
you purchase some other I/O 
board, be sijfe tS ask the 
manufacturer for details on 
setting the Baud rate for your 
Baudot machine. By the way, 
not all Baudot machines are 
60 wpm. Some are 65 and 75 
wpm. Gear sets are available 
from surplus dealers to 
change speeds. Model 1 5s 
work well at 75 wpm. Model 
28s are 100 wpm standard. 



How Does Baudot Look in 
the Computer? 

The answer to this 
question depends upon the 
configuration of the interface 
system. Consider, for 
instance, a typical keyboard 
entry to the CPU accumu- 
lator. The normally closed 
keyboard contacts can 
produce a logic or a logic 1 
depending on the number of 
inversions that take place in 
the I/O interface. In addition, 
the interface circuit will 
determine the location and 
order of the five level code in 
the eight bit accumulator. As 
an example, consider the 
letter T as it might finally 
appear in the accumulator: 

[T]* 020 001 017 035 

These examples assume the 
lower five bits of the ace urn u- 



*This bracket set will be used to 
mean the octal value of a five 
level Baudot character. 



lator are used. A choice must 
be made from this group if 
standardization is to be 
achieved, After consulting a 
few^ sources, 020 appeared 
the best representation. The 
MITS and Processor Tech- 
nology boards produce this 
representation. Table 2 pre- 
sents the full Baudot 
character set as it would 
appear in octal nqtation. 

For those not familiar 
with the Model 15s, upper or 
lower case is set by FGS or 
LTR keystroke respectively, 
A mechanical flip flop holds 
the case until another FGS or 
LTR keystroke produces a 
change. It is convenient in 
some systems to use a sixth 
bit to indicate which case is 
desired or the status of the 
machine. With the sixth bit, 
software can be written to 
control the FGS/ LTR func- 
tion. This relieves some of the 
difficulties encountered in 
keeping track of the case. An 
example will be presented 
subsequently. ■ 



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TTL's 

7400 .. 

7401 .. 

7403 .. 

7404 .. 

7405 .. 

7406 .. 

7407 .. 
7411 .. 
7413 .. 
7430 ., 
7437 ., 
7442 . 
vug hatf^. 



...20 

. . .20 
...20 
.. .25 
. .25 
. . .45 
. . .45 
. . .30 

...20 

..,50 
,1.10 



7475 . 

1490 . 

7492 , 

74121 

74123 

74tS2 

74165 

74TB6 

74177 

741B1 

74192 

74193 



-.80 
,80 
. 80 
. ,60 
. 1.10 
. 1.25 
.2.00 
, 1,75 

1.35 
- 3 90 

1.50 

1,45 



Wp quote on Bfty device 3t any qitsnuty. Ait tt^rm p^npaid S5.C0 
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M 




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BO 



featuring MITS Altair Computers 

HILL SDMCE COHIPIITEI SIOIE 

Byte'Tronics is the hobbyist's dream come true. A full seivice computer store featuring 
the full line of Aitair Computer products backed by the most complete tectinical sen/ice 
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The prices at ByteTronics are IWITS factory prices and most items ore avaiiable on 
an off-ttie-sheif basis 

ByteTronics sponsors the local Attair Users Group of East Tennessee and ByteTronics ts 
interested in communicating with computer hobbyists throughout the world. 

If you hove a question about Altair hardware (whether or not you are a ByteTronics 

customer), we will put you airectly in touch with our Technical Director, Hugh Huddelston. Hugh 
is an expert troubleshooter who has a thorough knowledge of each portion of each Altair 
board. And he can answer all your questions about custom interfacing. 

If you have questions about software " ■' if you want some custom programming, our 
Software Director, Johnny Reed, is the expert who can take care of your needs. Johnny has 
hod yeors of programming experience, and he is familiar with Altair BASIC, bssembler and 
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If you hove questions about the avatlabililyof a MITS product or its price or specifications, 
we will let you talk to Bruce Seals, bur Director of Marketing. 

At ByteTronics we want you to understand your Altair and we are willing to give you all 
the technical support you need, 

ByteTronics sells computers. ByteTronics sells service. 

For more Information, visit our store In Knoxvilie-or write or call us. We want to hear 
from you, 






WATCH THIS SPACE NEXT MONTH FOR IMPORTANT NEWS 

5604 Kingston Pike, Knoxvllle, Tennessee 37919 Phone 615-588-8971 
Office hours: 10 a.m. to 10 p.m. Monday-Friday and 9 a.m. to 10 p.m. Saturday, 



WHY SETTLE FOR LESS 
THAN A COMPLETE 6800 SYSTEM 



MEMORY 



All Static memory with selected 2102 IC's a 
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holds 4,096 words of this 
proven reliable and trouble 
free memory. Cost- 
only $125.00 for 
each full 4K 
memory. ^ 



INTERFACE^ 

Serial confndl interface connects to any RS-232, or 
20 Ma. TTY control terminal. Connectors pro- 
vided for expansion of up to eight interfaces. 
Unique programmable interface circuits 
a flow you to match the interface to al- 
most any possible combination of 
polarity and control signal ar- 
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individual interface. All 
this at a sensible cost 
of only $35,00 for 
either serial, of 
parallel type 




PROCESSOR 



"iViotorola" M6800 processor 
with Mikbug® ROM operating 
system. Automatic reset and load- 
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Motorola evaluation set software. Crystal 
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for the interface circuits. Full buffering on all data 
and address busses insures ''glitch'' free operation with 
full expansion of nnemory and interfaces. 



DOCUMENTATION— 

Probably the most extensive and complete set of data available for any 
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Computer System 
with serial interface and 2,048 words 
of memory , .$395.00 



wr^^fimfm^ 



^/0mthuiiiUm*i . 




GSOO sysT6M K 




D Enclosed is $395 for my SwTPC Computer Kit D Send Data 

D or BAG #_ . 

□ or MC Ex Date 



NAME 



ADDRESS 



CITY 



STATE 



ZIP 



j Southwest Techrtical Products Corp., Box 32040, San Antonio, Texas 78234 

I 



DIGITAL DATA RECORDER 

for 

Computer or Teletype Use Up to 4800 Baud 



Uses tJie industry standard tape saturation method to beat all FSK systems ten to one. No modems or FSK decoders 
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SPECIFICATIONS: 

A. Recording Mode: Tape saturation binary. This 
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C. Inputs: Two (2). Will accept TTY, TTL or RS 
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E. Erase: Erases while recording one track at a 
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F. Compatibility: Will interface any computer 
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* 



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NATIONAL MULTIPLEX CORPORATION 
3474 Rand Avenue, Box 288 
South Plainfield, New Jersey 07080 



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I 



NATIONAL IVIULTIPLEX CORPORATION 

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SHIP TO: 






. . Data Recorder @ $149.95 

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□cash nCheck □ Bank Am erica rd 



Please enclose $2,00 
Shipping 8t Handlmg 

IMJ. Residents add 5% 
Sales Tax 



□ Master Charge 




Card No. 



Expiration cfaie^ 



Signature. 



Total enclosed $. 



S3 




Louis L Hmion K7YZZ 
} 22 JS SE 62nd Street 
Beilevve WA 9BQ06 



Code Converter 
Using PROMs 



ASCU 



■HldJik 




STROBE 
BIT a 



M 



(5l)*UPPEft 
CASE 
LTR 



B> LOWER 

C4SC 

LTR 



aire 



Fig. }. Schematic. 



84 



Several amateur builders 
have advised me that 
they have had difficulty in 
obuining the National 5220 
BL/N code converter used in 
the RTTY TVT^ unit. It seems 
that the supply houses do not 
want to sell them in single 
quantities, but only in three 
at a time. This makes the cost 
much too high and one is [eft 
with the problem of what to 
do with the extra chips. 

Since it seemed that this 
was going to be a big problem 
in duplicating this circuit, t 
decided to redesign the 
circuit around a chip that is 
available in quantity and at a 
much lower cost. The 5220 
BL/N costs almost $20 eachp 
whereas the 8223 PROM 
surplus cost is around $3.00 
each. The parts count was 
also reduced during the re- 
design. The 8223 PROM may 
be found in several surplus 
advertisements in 73 Maga- 
zine. 

The 8223 PROM must be 
programmed to do the code 
conversion. Several articles on 
PROM programmers we re 
studied and the unit shown in 
the drawings was built in one 
evening* This code conversion 
provides alt the Figures and 
Letters found on the Model 
28 keyboard. 

Circuit Description 

The circuit is essentially 
the same as that used in the 
original RTTY TVT, but the 
5220 BL/N has been replaced 
by two 8223 PROMs. DC 
pulses from the TTY loop are 



coupled to the UART 
through an optical isolator 

and inverter. The parallel out- 
put of the UART is con- 
nected to the 7430 FIG-LTR 
case detector and to the inpui 
of the two 8223 PROMs. The 
outputs of the PROMs are 
paralleled and connected to a 
buffer for output isolation. 
The upper and lower case 
letters feature was retained 
for use by the video readout 
circuit. The two 7430s d^^ 
wired to recognize the FIG or 
LTR Baudot code and to 
trigger the 7400 FF causing a 
high to appear on pin 15 of 
the selected 8223. If the LTR 
key is struck, a high will 
appear on pin 1 5 of the LTR 



8223 and a low will appear 
on pin IS of the FIG 8223. 
The strobe pulse on the 
output of the strobe SS wilt 
also be Inhibited. The 
Carriage Return, Line Feed, 
and Stop keys are pro- 
grammed by the PROMs to 
present a blank signal to the 
TV video readout unit. The 
builder will also note that I 
have deleted the ROM input 
buffer and all pull up resis- 
tors. 

Construction 

The new code conversion 
board is the same size as the 
old one (4!^ by 6 inches). A 
layout of the board's major 
components and schematic are 



provided. A diagram of the 
programmer I built along 
with a layout of th front 
panel is also providet The 
program for the 8223 when 
used in this code conv rsion 
unit is shown in Table 1. 

I used point to point 
wiring for the circuit board. 
The pin connections on the 
connector were the same for 
both the old and new boards 
so I could check out my 
circuits with the least amount 
of fuss, I wired up the clock 
first and checked it for 
proper operation and 
adjusted it to the proper fre- 
quency for 60 speed opera- 
tion. 1 then wired ihe input 
circuit to the UART and con- 



Fig, 3, Programming unit for 8223 PROM, 



•7J, March 1976 




&M66 

<&^COOE WPUT 



Fig. 2 Paris layout, 



65 



M 





s 




Y 




M 




B 




O 




L 


B1 


A 


1 


B 


1 


C 





D 


1 


E 


1 


F 


1 


G 

LJ 






B 












LETTERS PROM 














Y 




























M 












LTR PROM 
















(-1- 

o 






BAUDOT 




Pin 15 State 








ASCII 








L 


B1 


82 


83 


B4 


B5 


B6 


B1 


B2 


B3 


B4 


B5 


B6 


B7 


A 


1 


1 





Q 







1 



















B 


1 








1 


1 




D 


1 
















C 





1 


1 


1 







1 


t 
















D 


1 








t 













1 













E 


1 
















1 





1 













F 


1 





1 


1 










1 


1 













G 





1 





1 


1 




1 


1 


1 













H 








1 





1 























i 





1 


1 










1 


















J 


1 


1 





1 


Q 







1 















K 


1 


1 


1 


1 







1 


1 







Q 







L 





1 








1 










1 












M 








1 


1 


1 




1 





1 












IM 








1 


1 










1 


t 
























1 


1 




1 


1 


T 












P 





1 


1 


D 


1 























Q 


1 


1 


1 





1 




1 


















R 





1 





1 


a 







1 


Q 












S 


1 





t 










1 


1 















T 





a 








1 










1 












U 


1 


1 


t 










1 





1 


D 




Q 




V 





1 


1 


1 


1 







1 


1 












w 


1 


1 








1 




1 


1 


1 












X 


1 





1 


1 


1 










Q 


t 









Y 


1 





1 





1 




1 








t 









Z 


1 











1 







1 





1 









FIG 




























LTR 


1 


1 


1 


t 


1 



















1 





CR 











1 






















T 





LF 





1 




























1 





SPACE 








! 

























1 





S 












FIGURES PROM 














V 




























M 
B 












F!G PROM 
















O 






BAUDOT 




Pin 15 State 






ASCII 










L 


B1 


B2 


B3 


84 


B5 


Be 


Bl 


B2 


B3 


B4 


85 


B6 


B7 


1 


1 


T 


\ 





1 





! 


















2 


1 


1 








1 








1 















3 


1 

















i 


1 















4 





1 





1 














1 












5 








Q 





1 





1 





1 












e 


1 





1 





1 








1 


1 












7 


1 


1 


1 





Q 





1 


1 


1 












8 





1 


1 









































1 


1 





1 





Q 

















1 


1 





1 
























• 








1 


1 


1 





D 


1 


1 












t 








1 


1 














1 












i 


1 


1 


t 


1 



























) 





1 








1 





1 















Q 


? 


1 








1 


1 





1 


1 


1 




1 







/ 


t 





1 


1 


1 





1 


1 


1 












9 

Ik 





1 


t 


1 











1 







1 







9 
* 





1 


1 


1 


1 





1 


1 







1 







\ 


1 





1 


1 








1 



















it 


1 











1 








1 
















1 


1 


1 





\ 








1 


1 


1 













& 





1 





1 


\ 








! 


1 













s 


1 








1 














1 













STOP 








1 





1 

























— 


1 


1 











Q 


1 





1 


1 










BELL 


t 





1 














1 


1 





1 








FIG 


1 


1 





1 


1 

























LTR 




























CR 











1 




























LF 





1 


































SPACE 








1 
































Table L Code conversion table for programming the 8223 PROM in the Baudot to ASCff 
R TTY TVT. 



nected the bridge into the 
TTY loop circuiL A check 
was made to assure that the 
parallel Baudot output code 
was appearing properly on 
pins 8 through 12 on the 
UART. The Strobe Pulse 
Generator was wired next and 
again checked to be sure that 
the 500 microsecond puise 
was being generated when a 
key was depressed on the 
keyboard. The FIG/LTRcase 
detector was then wired and a 
circuit check was made to 
confirm thai pins 6 and 8 of 
the 7400 FF changed state 
when the FIG and LTR keys 
were depressed on ihe key- 
board. Then the final wiring 
was made on the 8223s and 
the output buffers. The board 
was again plugged into the 
system and a check of all 
letters and figures was made 
to be sure that the PROMs 
were correctly coded, it all 
worked just as planned. 

The PROMs have been 
programmed so that the 
RTTY TVT screen does not 
print any Greek alphabet gar- 
bage when the CR, LF and 
other selected non-wanted 
characters are struck. On the 
old preprogrammed 5220 
BL/N you had a few Greek 
characters show up every 
lime the FIG, LTR, Bell, or 
STOP characters were 
received or transmitted- When 
you do your own program- 
ming, you can prepare it so 
that this does not happen. 
Another blow for those who 
build their own gear. 

This new version of the 
RTTY TVT code converter 
board should enable the 
builder to fabricate his unit 
with much less fuss over 
trying to locate hard-to-get 
components and in the pro- 
cess reduce the cost of the 
unit." 

'*K20AW Synthesizer PROM- 
oted," Wm. J. Hosking W7JSW, 
73 MagazinB^ November/ 
December, 1975. 

"A Versatile Read Only Memory 
Programmer/' Peter Helmers, 
BYTE Magazine, November, 
1975, 



m 



36 





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CORFaRArON 



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EdiinhfuL lJi^hR4CllO 



(801)292-8466 



73 Magazine Staff 



A Nifty 



Cassette 



Computer 




The most practical and 
economical way to store 
programs and large quantities 
of data for small computer 
systems is with the common 
tape cassette recorder. Cheap 
and plentiful^ audio-type 
cassette equipment is capable 
of storing several times the 
amount of data that an 
equivalent volume of paper 
Upe can hold, with the added 
benefits of erasability and 
easier operation. Floppy disks 
may be faster, but are beyond 
the price range of most 
hobbyists. 



While computer manufac- 
turers and software houses 
have long been supplying 
their programs on audio 
cassetteSj there has been a 
major problem with com- 
patibility. Every manufac- 
turer has had his own pet 
system of recording, and a 
tape recorded for use with 
one brand of computer is 
utter gibberish to another 
brand of computer. For this 
reason, several manufacturers 
decided lo adopt a standard 
system of tape interfacing. 

The proposed standard, as 



LSB 



2? 



6 BIT 
PARALLEL ( 

INPUT 



£8 
29 



MSB 
OK TO LOAD 



LOAO IT 



30 

li 
32 

33 
23 



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MART 

TRANS- 
MITTER 




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1/6 4049 




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4027 

15 _ 6 



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1 



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implemented by Proneiics 
Corp,, calls for a frequency- 
shift keying standard not 
entirely dissimilar to that 
used for RTTYj but with 
several crucial differences. 
The two tones to be recorded 
are ideally to be square 
waves, with Mark {logic 1 ) to 
be 2400 Hz, and Space (logic 
0} to be 1200 Hz. With a 
standard tape exchange speed 
of 300 baud (bits per 
second )» Mark would consist 
of eight cycles, Space of Tour. 
This could be divided to 600 
or 1200 baud, in which case 
one cycle would be a space 
(1/1200 sec). Higher density 
would be impractical. For 
comparison, 300 baud corres- 



Rl 
100 K 




— ^ Ci 

*7^ 005 




AUXt'^OOmVj 
P - P 



p-p 



Fig, L Cassette digital modufaton This circuit conwrts 8-bit paraffel input data to a series of 
2400 and J 200 Hz tones for recording on cassette tape, 

T 



ponds roughly to 30 

characters per second. 

Within each character, the 
first recorded tone should 
consist of a Space (start) bit, 
followed by eight data bits 

(least significant bit first, 
parity last} and two Mark 
(stop) bits. All undefined 
bits, as well as the interval 
between characters, would be 
Mark (2400 Hz). 

This system has several 
beneficial features. It is self- 
clocking. The first bit of any 
character is Space and must 
follow the Mark tone that 
ends previous characters and 
exists between characters. U 
is possible to tolerate as much 
as a 30% speed variation with 
this system, which can be an 
important Factor with inex- 
pensive tape equipment- 



Do I Need a Good Recorder? 

Almost any cassette 
recorder can be used for data 
storage using this FSK stan- 
dard system. But for con- 
venience and accuracy, there 
are a few criteria for selection 
that differ from hi-fi quality. 



M 



SB 



You want a clean, reliable 
machine. Dirty heads and 
mechanism can spoil data 
very easily, tf you don't have 
a cassette recorder already, a 
used model is adequate, but it 
shouldn't show signs of 
mistreatment. It should also 
have capstan drive — a few 
miniature units don't, 

A digital tape counter is 
also a great convenience. 
Without one, identifying 
programs on a tape can be 
difficult, and could lead to 
accidental erasures. These are 
found on many hi-fi type 
machines, and occasionally 
on portable units. 

An important electrical 
feature is ac bias/erase. Some 
recorders, and most of the 
under-$100 category, use dc 
for erasing and record biasing. 
This results in higher noise 
and less frequency response. 
While frequency response is 
not as critical with this 
system as with music record- 
ing, it still helps to have a 
good clean treble response, 
which can help preserve the 
square wave shape. Low noise 
means fewer errors, so a high 
signal-to-noise ratio aids relia- 



Stereophonic capability is 
unnecessary. If you have a 
stereo recorder, be sure to 
record both tracks simultan- 
eously, and bulk erase the 
tape before using it. 

Your tape recorder must 
have an auxiliary or micro- 
phone input jack, as well as 
an earphone or line output. 
Acoustic coupling Is unsatisr 
factory. The choice of levels 
can be performed in the com- 
puter interface circuitry, so 
either mike, line, or speaker 
levels can be used. 

What About Tape? 

While the choice of tape 
recorder is uncritical, the tape 
itself is the weak link in the 
chain. Do not skimp on tape. 
Use the best tape you can get 
your paws on. Since dropout 
on the tape means toss of 
data, the tape must have a 



In a meeting orpnized by the staff of 73 
Magazine, the microcomputer industry 
accepted this cassette system as the 
industry standard. 



high manufacturing standard. 
Some cassettes jam easily, 
and the thin tape found in 
C90 and CI 20 cassettes is too 
ihin and fragile to be reliable. 
A premium grade C60 tape is 
ideal. Perfectionists might 
want to spend the extra 
money for chromium dioxide 
tape. The extra response can't 
hurt. 

Store the tapes in a dust- 
free location, in their own 
container. Do not smoke near 
the tapes or the recorder, and 
clean the heads frequently. 
Tape cleanliness and quality 
are far more important in 
digital applications than in 
music. 

The Recording Interface 

Digital information from 
your computer is generally 
available as 8 bits parallel 
from either an I/O port or 
data bus. The tape is recorded 
serially; the conversion is best 
accomplished with a Uni- 
versal Asynchronous Re- 
ceiver/Transmitter (UART) 
IC 

The modulatot^ is shown in 
Fig. 1. The serra! output of 
the UART has logic 1 as a 
high level and logic as a low 
leveL IC2a and IC2b form a 
clock divider circuit, dividing 
the 4800 Hz clock signal by 2 
or 4, depending on the UART 
output leveL The output is a 
series of square waves which 
feed the tape recorder's 
input. 

The poor frequency 
response of some tape 
recorders, especially those 
with dc bias, causes the man- 
ufacturers to exa^eratc the 
treble being recorded, which 
distorts the square wave. Sine 
waves record be tier, but are 



harder to generate digitally. 
In some cases using a low pass 
filter makes the waveform 
usable; Rl and CI perform 
this function. A smaller value 
for CI may increase effective- 
ness with better recorders. 
Fig, 2 shows the effect of the 
recording process on digital 
waveforms. 

The AUX output of the 
interface is 500 mV peak-to- 
peak and is for use with high 
impedance high level inputs. 
The MIC output is 50 mV, 
suitable for most units with 
microphone inputs. 

The 4800 Hz signal must 
be capable of driving two 
TTL loads. While a crystal 
oscillator and divider chain 
work best, and a phase locked 
loop referencing the 60 Hz 
power line Is also very good, 
the oscillator in Fig. 3 is 
simple and quite satisfactory 
(but requires calibration with 
a frequency counter). 

If the available digital 
information from the com- 
puter is already in serial form 
with the necessary start and 



two stop bits, and is properly 
timed at 300 baud, the 
UART is fK^t necessary. How- 
ever, the 4800 Hz clocking 
signal should be synchronous 
with the serial data, with 16 
clock pulses per bit. If the 
serial data is not at 300 baud, 
a UART receiver must first be 
used to convert the data to 
parallel form. It then is 
clocked through the UART 
transmitter as shown. 

The OK TO LOAD line on 
the UART goes high when it 
is ready to accept a byte of 
parallel data. The data is then 
loaded into the UART trans- 
mitter by pulsing the LOAD 
line low for at least one usee 
or until the OK TO LOAD 
line goes low. The transmitter 
will then start transmitting 
the byte when the LOAD line 
is returned to the high state. 
When not transmitting, the 
output is high, causing the 
modulator to generate the 
2400 Hz Mark signal. 

The Playback Interface 

There are several possible 
ways to recover the FSK signal 
from the tape. An FM dis^ 
criminator or a phase locked 
loop demodulator can be 
used, just as with an amateur 
RTTY signal. Users of pre- 
vious no n standardized 
cassette interfaces can re- 
adjust them to decode the 
1 200/2400 Hz tones, but the 
most accurate system uses 




-\aaaAAAAw 

Fig. 2 if a square wave signal sucii as v^veform A is recorded 
on a fow cost cas^tte recorder, the piayback response may 
look like wamform B, wliich is i/ery difficult to demodulate, ff 
the square wave is filtered with a tow pass filter before 
recording (waveform C), the playback response will appear tike 
waveform D^ a usable signal, 

1 



39 




45 



^f 



,^ ADJUST FOR 
^^ 4600 Hi OUTPUT 




4SOOH1 



.01 



Fig. J. Ctrcult of 4800 Hz 
oscillator. Use this ctrcult if a 
^ more precise and stable 
source of 4800 Hz Is not 
aVQilabte. 



digital recovery to extract 
liming informalion from ihe 
recorded signal and uses that 
informalion to retime the 
recovered data. 

Fig. 4 is a complete sch(^ 
matic of the playback demod- 
ulator. The signal from the 
cassette player is conditioned 
by IC3, an op amp used as a 
SchmEtt trigger. The output 
of a Schmitt trigger is, by 
definitionj either fuily high or 



low, so it regenerates pure 
square waves from the 
distorted tape input. IC4 is a 
retrjggerable one shot with a 
period set to 555 micro* 
seconds. As long as the input 
signaf is 2400 Hz, the one 
shot is retriggered before it 
times out. Flip Oop !C5a 
remains high, which is inter- 
preted as logic 1* The 1200 
Hz signal, on the other hand, 
has a period between pulses 
of greater than 555 usee, so 
the one shot times out, re- 
setting IC5a. It stays at logic 
as long as 1200 Hz is being 
received because the one shot 
is timed out whenever the 
next triggering edge occurs. 

When the 2400 Hz signal 
returns, the one shot stays 
high, permitting IC5a to 
switch back to high state. The 
output of this flip flop is the 
serial data. 

While that simple circuit 
will work well if the tape 
speed is accurate to better 
than ±6%, such is frequently 
not the case. Since tape speed 
variations will be reflected in 
pitch variations in the re- 
covered tones^ it is possible to 



C4 

,005 

MYLAR 



R8 
?7K 







lC3o 
r/4LM324 



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ICSo 
1/2 *0J3 



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ONE SHOT 




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1. 

X 



NR2 DATA 



use the 1200 and 2400 Hz 
signals from the tape to 
retime the recovered data. 
Flip flops lC6a and IC6b 
extract this timing informa- 
tion. When the 1200 Hz 
signal is received, lC6a is 
preset with a pulse generated 
by C8 and R15 every time 
the one shot times out* The 
effect is to cause 1C6 to 
divide by two. When 2400 Hz 
is being received, the one shot 
does not time out and IC6 
divides by four. The result is 
a clock at the output of IC6b, 
at 600 Hi. 

Instead of clocking the 
data into a shift register, I he 
receiver portion of DART 
I CI is used. It has built-in 
circuitry lo identify the start 
and stop of each byte auto- 
matically. It also has three* 
state output (logic low, logic 
high, and functionally discon- 
nected), which permits direct 
connection to most data 
buses and I/O ports. The 
UART needs a 16x clock, 
which is formed by phase 
locking a 4800 Hz oscillator 
lo the 600 Hz output of 
IC6b. The PLL is adiusted to 



oscillate at 4800 Hz in the 
absence of any input signaK 
IC5b and 1C9 divide ihe PLL 
output by 8 to drive one of 
the phase detector inputs, 
while the other input is 
driven by IC6b, 

The UART receiver raises 
its DATA AVAILABLE 
output to logic 1 when it 
recognizes that il has received 
a complete character. Since 
the UART outputs are three- 
state, it is necessary to drive 
the RECEIVED DATA 
ENABLE input to logic to 
read the paiallel output data. 
After the parallel data has 
been read it is necessary to 
pulse the RESET DATA 
AVAILABLE line to prepare 
the UART to output the n^xt 
byte. The pulse must remain 
at logic for at least one 
usee, or until the DATA 
AVAILABLE line drops to 
logic 0. 

Circuit Adjustments 

The only adjustment 
necessary for the recordirig 
modulator is to put the 4800 
Hz signal exactly on fre- 
quency. Since a Mark byte 



^-S -12 



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1/6 4049 



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10 K 



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QQ( ICBb 

4800 yf^ 4049 
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B13 IRI4 
lOOK f^K 

C7 



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8 



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DATA 

UART 
RECEIVER 



CLOCK 



171 iif 



MSB 

7 _ 

fi B BITS 

) PARALLEL 
2^ OUTPUT 

1 1 

12 

19 ""lSB 
.^Z^DATfl AVAIL 

L&V RESET DATA 
AVAlLJi r 

oufpuT 

ENABLE 



II 



10 1/2 4013 



IC91) 



rcso 



iCSb 



a 



90 



Fig. 4, Cassette data recovery circuit. Refer to text for circuit operation. 



consists of eight (not seven or 
nine) cycles at 2400 Hz, this 
is fairly critical. 

Tlie data recovery one 
shot and PLL oscillator must 
be accurately adjusted for 
best resuEls. The one shot is 
critical. To adjust it, set a 
well calibrated audio source 
to 1800 Hz with 1,5 to 3,5 V 
rms output. Adjust R9 until 
the data output of ICSa pin 1 
just changes, measured on a 
high impedance voltmeter. 
Adjust R9 10 as close to the 
point of change as possible. 

The PLL oscillator is 
adjusted by R12 with no 
input to the playback input. 
If no counter is available, the 
oscillator output at fC7 pin 4 
should be compared to the 
4800 Hz signat used for the 
UART transmitter. 

Circuit Operation 

The circuit as shown will 
recover data most accurate! y 
if the earplug output signal of 
the tape recorder is between 
4 and 10 volts peak-to-peak. 



Most portable recorders have 
that capability. If the cassette 
deck does not have a speaker 
amplifier, a low gain amplifier 
may be necessary. If the 
recorder uses dc bias, there 
may be too much treble, 
which necessitates turning 
down the tone controL 

To comply with the stan- 
dard for tape exchange, the 
recorded data should be pre- 
ceded by at least 5 seconds of 
2400 Hz tone before the data 
begins. This is accomplished 
by operating the recorder in 
the record mode for five 
seconds or longer before 
sending data to the UAKT 
transmitter. With the UART 
idle, the modulator generates 
2400 Hz. 

During playback, wait a 
couple of seconds before 
allowing the computer to 
accept the UART receiver 
output^ to avoid reading the 
garbage generated by turning 
the recorder on and off. It is 
possible to have the computer 
control, via a relay, the 



r MflflK- 



SlGNAL TO BE UOGlC OMf J 

Rf CORDED 
UUXJ 



SPACr- 



(LOGIC ZfRO» 1(LOGICOF4F} 



«ARH' 



AA/W\AAA/\/\y\yV\AAAAAAA/^^ 



CMCMTIONEO 
PtAYBACM 

SIGMA L 
4IC3itl 

«fCOVC»Y 
ONE SHOT 
[IC41 

fiE COVE RED 
NRI CkATjl 

IC«4 

i2n ci.t>c»t) 



aofuiniinjinjijnjTJimumnjmrux^ 



iririnj 



innnr 




Fig, 5, Cassette modulator}demodulator waveforms. 



remote control switch of the 
tape recorder under program 
controL It is still necessary to 
wait a few seconds before 
accepting data, due to the 
time spent starting and 
stopping the tape. The 2400 
Hz leader provides that 
interval on the tape. 

Conclusion 

Using this type of hard- 
ware for tape cassette modu- 
[ation and demodulation 
simplifies programming for a 
cassetten^riented computer 
system. In some circum- 
stances it may be possible to 



connect the interface hard- 
ware directly to the com- 
puter, while some computers 
may require peripheral inter- 
face adaptors to get the data 
in and out of the computer. ■ 

The cassette mterface 
described here is manufac- 
tured by Prone tics Cor porn - 
tiort. It is available fully 
assembled and tested art a 
4,5" X 6,5" circuit card with 
starfdard edge connector. For 
price and otfjer information 
write: Prone tics Corporation, 
PO Box 28582, Dallas TX 
75228. - Ed. 



PRINTED CIRCUIT 

Positive Acting Photo Resist; Carbide 

bits; Bubble etchers; Artwork; Epoxy 

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Send stamp St address label for flyer 
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FM CONVENTION AND FLEAIWARKET 

MAY 15&16, 1976 

Downlown Ramad^ Inn. Durham, NorTh Carolina 

FBATURfNG 

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For ft&servatJQns (B^itquet sftd Accommodbtiofis/ 

WRITE: DURHAM FM. ASSOCIATION, INC. 

Post Office BoK 3&51 
Otirham, North Carolina 277Q7 




FOR ApSSmONiU. INFDraiAniJN 
*Mjt We:S£l5V AXIOMS WRfTt TO 
ARRL NATIOIyAL COfJVBSmOfti 
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24SD SOUIN OJlTyAKl 
DEIWEB COLOHAIJO SORIIS 





Surplus Test Equipment 

Free Information 

AMERICAN CALIBRATION SERVICES 

P.O. Box 8104 Athens, Georgia 30601 



91 



IS 



MMH 



alphanumeric display 
generated with 
Dazzle-Writer software 
(see below) 





Now your 

color TV can be your 

computer display terminal 



New capabilittes, loo 

Cromemto's new compuier/tv interface 
circuit lets you l>ave a fuli<olof compiner 
display terminal fof little more than a 
black-and-white terminal. 

The Cromemco imerface also lets you do 
vastly more wiih your color terminal ilian 
you can do wiih ordinary black-dnd-whiies. 

We call our interface the TV Dflr.zler^. It 
consists of two circuit boards that plug 
dlrectlv into your Allair SEOQ or IMSAI 
S080 computer. 

Alphanuffiefks pltjs action, and graphics 
The Da/^ler^ maps your computer 
memory content onto your color tv screen 
ifi full color. 

That doesn't mean just that you see 
alphanumerjcs In color You can display any 
toformation in memory. And do so in color. 

LIFE in color 
You can dispUy computer garner or 
animated shows (fOci(;et ships). What's more, 
you can display business or technical 
graphics - multi-colored charts^ graphs^ 
histograms, educational material - jill from 
computer memory. Even lighi shows. Not 
even the beggest coRipiiter manufacturers 
offer all this in color. 




Nc«ls only 2K memory: 
Technically, the Da^^ler® scans your 
computer memory using direci*mcmory 
access (DMA), ji formats each memory bit 
into a pom I on the iv screen to give a 
12Sx 128-etement prcture. Only a ZK-byte 
computer memory is re^iuired (only 512 
bytes for a 32 x 32 picture). The quality of 
the pictures b evident in the photos. 

The Dazzler^ output is a video signal 
thai goes dtrectty to the tv video amp or to 
the antenna terminal through an mexpeosive 
com mereial I y -aval lab le de v ice, 

tnex pensive - and so much bettcf 
You can see from the list below that the 
DMiht® is little if any more in price than 
an ordinary b/w interface or tv lypcwriier, 
6ui it does so much more. 



Order now 

By mail or at your computer store 

it you're into computers (or want to be), 
if you want to mvcnt these beautiful 
displays or games, or lo plot colorful 
material ines pensively at home or jn 
business, the Daizler^ is for you. 

Not only is it reasonable^ but it's sold at 
computer stores from coast to coast. 

Or order directly by mall on your bank 
card. 



TV AZZ LE B^' (complett kit) , 

TV DAZZLEfl^ (fully assemblett 

anci tested) ,,.,,,, 



S2t5 



S350 



SQFTW/ARi 
(punched paper tape with documentarion) 

LIFE m(un color S15 

KALEIDOSCOPE irtM color . . . . St5 
DAZZLE WRITER (for alpha- 
numeric displftys in color} * * ... Sf 5 

Shipped prepaid if fully paid with or^ir. 
California users add 6% s^les tax. 

Maslerchargo and BankAmericard accepted 
with s^gn«d ordfif. 

Oiiimry: from stocl^ for immediate shipmnt 



aCramemco 
specialists in computer peripherals 
One First St., Los Altos, CA 94022 • (415) 941-2967 



Yducanbuy 




We would be a bit surprised if you 
could do anything meaningful without 

additional hardware and software. Mc 

Wave Mate's Jupiter II"'* isn't the kind of 

microcomputer kit you only stare at . • . when 

youVe completed your Jupiter II just plug in 

your terminal and you're ready to go. That's 

because it goes beyond the sum of its high 

quality parts. It's the ultimate micro kit 

experience. In performance, in documentatioii, 

in reliability , Firsts consider its superb features. 

It has small pluggable wire wrapped cards 

easily tailored to suit your modifications. 

Every IC is socketed and 100% burn-in tested, 




In fact every part including the powerful 
MC 6800 CPU and the 8K dynamic RAM 
SBO(* is guaranteed for 120 days. It has the best 
software around, System Monitor and Debug 
programs (ROM). Includes powerful text 
editor and Motorola compatible assembler. 
And BASIC at no extra cost. Because we've 
been making microcomputer systems for over 
4 years, we can offer you the broadest line of 
interfaces including TV terminal and dual 
audio cassette. Impressive. And yet the 
grandest feature is the experience f / f f\^ 
of completing a kit that works, L UU / J 
Guaranteed. v/m^M nhxu 



r 

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ACT NOW AND SAVE. ^^^*^ ""^i* ^^ * * ^'^^^ 
SPECIAL price $1 445.00 (assembled $1950.00) 



Jupiter II Microco 
Modular plug* in power 
supply 

9 mcKiule PC backplane 
CPU module 
Syst<?m monitor module 
SK. dynamic RAM 
module 
Seria! RS 232 
commurfcication interface 
module 

Front panel module 
Front panel 

Wire: cut, stripped, color 
coded 



mputerKit Includes: 

• Rack mount module ca^e 

• Wire wrap tool 

• Wire unwrap tool 

• Cables, connectors, all 
other nec(*ssary 
hardware 

• Software (editor, debug, 
assemhU^r, BASIC) 

• Assembly manuals 

• Operators manuals 

• Theory of operation 
manuals 

• Annual membership in 
users group 



next month watch for stupendous 

announcement/^ 

D Send Jupiter II micro kit* 

□ Kit □ Assembled 

□ Send details on kit-a -month 

Q Vm not convinced; send me 101 reasons why- 
(n Please send free Jupiter II System catalogue. 




B Check enclosed for $ 
dude $1 0.00 for postage and handling. California 
residents add 6% tax Delivery 60 days ARC 



Name 




Address 



City/Stat€/Zip 



WAVE MATE 

1015 West 190th Street Gardena, California 90248 

Telephone ^213) 329-8941 



as 



WARRANTY 

120 days on all parts, 
materials and workmanship. 



!■■■£ 



I 
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93 



u 



Silas S. Smith, Jr, WA9VFG 

2ZQ8 McCord 

Murphy sboro IL 62966 




Digital All That New? 



TO medJUte on an experi- 
ment^ a serious experi- 
menter often shelves today's 
experiment, perhaps never to 
lake it op again. The **light" 
was in the meditation and not 
in the experiment. This brings 
me to the point at hand - 
meditation as related to 
digital. 

For several years now, a 
transition from analog to 
digital has been in the pro- 
cess. To many people, digital 
is considered as a rather new 
development, but I ask, "Is it 
really all that new?" The 
question may suggest the 
answer that digital has been 
around for some time, 

just for the fun of it, let 
us take a brief and somesvhat 
abstract view of digital 
devices or communications 
through the age of man. 

From man*s beginning, he 
had a very good calculator at 
his fingertips as well as a 
computer with all the soft- 
ware that is necessary for lis 
operation, although he had 
very little need for either in 
his primitive culture. It was 2 
to 3 million years before man 
saw the need to communicate 
between computers. Man has, 
over the last 20,000 years, 
developed ways to communi- 
cate between computers. 

If the old axiom is true 
that a picture is equal to a 
thousand words^ and if we 
should equate the picture to a 

^ 94 



computer address and equate 
the thousand words to the 
memory of the computer, 
then the cave man had the 
basic idea in his cave drawings 
some 20,000 years ago. Pro- 
gramming his computer to 
accept more addresses (more 
pictures), he was able to 
develop a memory system 
called hieroglyphics, which 
used approximately 900 
pictures. Up to this time man 
had almost exclusively used 
analog, which is called the 
spoken language. Hiero- 
glyphic programming was too 
complex for most computers, 
so a much simpler system was 
developed using only about 
24 pictures, Hierotics, as this 
system is called, was very 
effective digital-wise, but 
lacked the ability to com- 
municate With analog 
systems. About 3^000 years 
ago a digital to analog and 
analog to digital system was 
developed. This system is 
often called phonic writing. 
Soon to follow was a digital 
system that was much more 
simple and was easily con- 
verted to analog. This system 
was made by the combining 
of the Phoenician phonic 
system and the Roman 
alphabet. Because this system 
had only 26 digits or letters 
and could be formed into 
word groups, it was adaptable 
to programming. Such pro- 
grams are placed into a 



machine called a printing 
press and are read out into a 
permanent storage unit 
known as a book, which is a 
type of read only memory. 
With this type of ROM, the 2 
or 3 million year old com- 
puter design has almost un- 
limited capacity to perform 
the most complex problems. 

In Aristotle's theory of the 
universe formulated some- 
time around 400 BC, it was 
suggested that a binary 
system was possible. Such a 
system would consist of such 
variables as hot and cold, wet 
and dry, light and dark, etc. 

Much experimenting in 
digital communications was 
taking place by the mid- 
1 700s, parallel versus serial as 
each form was being 
developed. Static or friction 
electricity and its pith balls 
came first as a parallel system 
(i.e., one set of pith balls for 
each letter). Soon to follow 
was a synchronized serial 
form using only one set of 
pith balls, 

Galvan electricity and the 
use of magnetic needles went 
through the same parallel and 
serial development. However, 
a new wrinkle was added* The 
new wrinkle was code - that 
is, left or right, operated or 
non-operated. Us form was 
much like that of Morse code* 

From its inception in the 
mtd-1800s, the electromag- 
netic (telegraph) system used 



a code in serial form. It was 
the search for the conversion 

of the eiectromagnetic digital 
system to analog that (ed to 
the development of the tele- 
phone - which just happens 
to be an analog device. It was 
only a few years ago that the 
conversion of digital to 
analog and analog to digital 
was electronically accom- 
plished. Its form is called 
pulse code modulation. 

Just as in the addressing of 
electronic computers, we 
have been simplifying the 
addressing to the 2 or 3 
million year old design. Some 
examples include changing 
**The United States of 
America" to USA, and other 
conversions resulting in terms 
such as IRS, FCC, IBEW, 
NAACP, FBI, CIA, 73 and 
others. 

What is the answer to the 
question, "Is digital all that 
new?" I would say no. I 
would go so far as to say that 
at present we are not really in 
a truly transitional period but 
rather in a sort of jockeying 
position. As we turn the 
corner, 1 predict that the next 
big development will be a 3D 
computer that will make the 
present computer look like a 
small contribution to the 
overall communications 
system — but I see no way 
that the old 2 or 3 million 
year old design will ever be 
replaced. ■ 




^^A 



'^V 



I/O EDITORIAL 

from page 69 

your own if you want to ojstomize 

the programs to fit youf exact need* 
or K yotJ want to use the gear for 
some new application. Who knows, 
once you're set up you might want to 
score a ham contest and program your 
computer to cross check every re- 
ported contact on the incoming logs 

. that program would keep you out 
of trouble for a while. Or you might 
want to ar^tyze Oscar contacts for 
anomalfts to see if there are indica- 
tions of over the honzon propagation 
at times. 

The uses for your computer will be 
expending constantly as you discover 
new things you want to do , . , and 
learn mora atiout how to program the 
beast to do what you want. When you 
have worked sevefai weeks in youf 
spare time lo perfect a program, you 
are on the one hand a bit reluctant to 
\uu give away all that work to anyone 
who comes along ... on the other 
hand you are so proud of what you 
have accomplished that you want 
others to see how neat it is. I don't 
know how this will work out m the 
long run „, perhaps there will be 
some pirogrammir>g sales services to 
help you get a smail royalty for your 
effort . . . selling your program to 
those who want it for a few bucks. On 
the other hand, the magazines of the 
future may devote pages to new pro- 
grams , , . we'll see. 

Right now you can buy some pro- 
grams on cassettes . . . such as BASIC 
Language . . , a ham package from The 
Digital Group . and a few things 
like that, Much more is available in 
printed form . , , What To Do After 
You Hit Reti/rn is a book full of game 
programs and sample runs of the 
games to give you the idea. Digitai 
Equipment Corporation has a book 
iwhfch they don't want us to sell) of 
101 games in BASIC. Much of this is 
pretty much the same as the What To 
Do tpook which is published by 
Peopte'i Computer Company and is 
available for S6.95 from 73 .,, (ahem 
. . .comnf>ercialJ. 

The people who are selling pro- 
grams on cassettes get bent out of 
shape if you run off a copy for a 
friend, They spent a lot of tima 
(which is money} writing the program 
and getting it perfected (debugged) 
and they feel that you are steaUrig 
from ttiem if you don't pay the 
freight* A letter was jusi sem around 
to this effect by the chaps wtto 
developed the BASIC program for 
MITS. 

Software such as the MITS BASIC 
program is usually copyrighted, but 
this \i difficult to protect. It may be 
that programmers wiEl develop some 
smarts in this Hne . , . perhaps taking a 
hint from map pubfishers. Every map 
^ou see that is csopy righted has some 
^Mtra squiggles in the borders of a 
state or a country, or something 
which is not there in real life. Then, 
ivhcn you innocently take a gas com- 
pany map and trace out the part you 
/vanl and use it as an M lustration for 



your article or in a book, wfiaml One 
farge map maker pi^lls in over a 
million dollars a year in copyright 
infringenwnt cases, I am told. The fact 
is that it is awfully difficult to explain 
why your map has that squiggle over 
there or perhaps an extra town that 
just doesn't exist (a Cleartype Map 

favorite} particularly when the 

case is scheduled to come up in court 
soort 

Would it be that difficuft to cus- 
lomize each copy of BASIC wtih a 



little identifying (t>ut non-printir»g or 
operating} charaaer ? It would be hard 
to find and would make e^h copy of 
the program individually identifiable 
. . , and might put some teeth into 
contracts, Just an idea . , . I'm sure 
ways will be found to solve the 
software sales problems ... of course 
it might happen that programs will 
eventually just be part of the hard 
ware cost and be available essentially 
free. 

Ves, with this software you will lie 



able to get your computer to cto a lot 
of nice things . , , like play games. 8yt 
you will stilt have to learn how to do 
your owm program mir^g for anything 
off the beaten track. To put it into a 
percentage . . , argue with me if you 
like . , . figure 25% hardware . . . 25% 
language programming and 50% your 
own programming efforts. Once you 
get into computers you are gomg to 
have your harxls full . . , and you wilJ 
have 3 ball. You may even decide to 
go back to fresh orange juice. 



GET FAMILIAR WITH 

MICROCOMPUTERS 
AT MICROCOST. 

The EBKA FAMlUARiZOR 
is a complete 
microcomputer system. 
No expensive terminal is 
required. Everythirtg is 
buiil-in to a single PC 
board, mcluding a hexi- 
dedmal keyboard and display, 

Easy-to-undersland Hard- 
ware and Programming Manu- ^^. '^ _^^^^^K ¥V 
als guide you every step of the 
way. You will gain a practical 
knowledge of microprocessing, 
plus m valuable hands-of>" experi- 
ence All at microcost. 

The heart of the £BKA FAMlUAR- 
iZOR IS a MOS TECHNOLOGY 6502 
Microprocessor an eight fait processor 
that can address up to 65K bytes of 
memory. On-board memory consists of 
IK bytes of RAfVI for user programs and 
two eight bit ports (one input and one 
output). A 256 byte monitor program, supplied in one 1702A 
erasable PROM, enables you to load, examine, run, debug and 
modify your own programs. Each function can be impiemented 
at any address in memory. Breakpoints can be entered at any 

location in your program to display internal 
registers or branch to a separate routine. 

You may also expand the capabilittes of your 
FAMlUARiZOR in easy, inexpen&ve stages. To store 
your own programs in PROM, the PC board is designed to 
accept three additional 1702A PROMS (768 bytes). A low cost 
PROM programmer is also available. The system bus allows easy 
expansion. Add-on memory, interface and special function cards 
are available 

Whether you're a beginner or an experienced engineer. EBKA 
offers you a microcost way to get familiar with mjcrocomputers. 
Order your £BKA FAMlUARiZOR today. 



m, 



— ORDER FORM »ai>»»«»« 

please send me; 
n Complete 6502 

FAMlUARiZOR Kit ^„..$22g 

^ Assembled..........*.. ..S285 

HI IC Socket Kit .,„ $14.50 

3 Power Suppfy ...,,. ,...$58 

^ Check here If you wish to receive 
literature on the complete EBKA iine. 

Oklahoma residents, add sales tax- 

Make payable and mail to: 



r~l Enclosed is my check or money order 
forS 



r~[ Charge my 



r~] BankAmericard or 
□ Master Charge 
exp, date 




EBKP 



Account No 

M.C. Bank No. 



Signature. 



rNOJSTRIES INC. 

6920 Melrose Lane 405/787 3671 
Oklahoma City. Oklahoma 73127 



Name 



Address. 



City, State. Zip 



I 
I 
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95 



Wayne Ladder Wl EWL 
8 Overlook Drive 
Medway MA 02053 



The Ins and Outs 



of TTL 



The design of digital 
circuits using TTL inte- 
grated circuits can be much 
less frustrating if some simple 
rules are foi lowed. I am 
referring to the rules that 
dictate how and why inter- 
connections between the 
various circuits and the out- 
side world are made, If you 
follow the rules, you should 



be able to put together a 
digital circuit from TTL lO 
and only have to worry about 
wiring errors, logfc goofs, and 
bad ICs. The information is 
from the manul^ciurers' liter- 
ature and my own 
experiences on the bench. 



Ins 



The most common and 



GftlOOF NO IB 
WIRE^BOTTOM 
SIDE) FOR 
GROUIVD 



ELECTROLYTIC 
CAPACITOR 



GROUND 

TERMINAL 




most easily overlooked input 
of TTL circuits is the power 
supply. One look at any TTL 
circuit and you quickly know 
the value of the supply 
voltage is +5 V. For those 
who worry about such things, 
the tolerance is ±5% (military 
versions are ±10%). In other 
words, the manufacturer only 
guarantees proper operation 



PEflFORATEO 
BOARD WtTH 
HOLES SPACED 
OH Am. GRIP 



GR1D0FM0,IB 
WIRE tTOP 
SIDE] FOR +5V 



*5V TERMINAL 



Fig, L ff lustration of rules for power supply connections. 



of his ICs when the supply 
voltage is between +4.75 V 
and 5.25 V. This is not to say 
they won't work at other 
voltages - only that there is 
no guarantee. 

When TTL circuits switch 
they generate very high fre- 
quency current spikes on the 
power supply lines. These 
current spikes traveling 
through the high frequency 
impedances of the power 
supply lines cause voltage 
spikes which can couple into 
other circuits and trip flip 
flops, clock counters, and do 
all sorts of nasty (and very 
difficult to find) things. To 
protect yourself from this 
problem these power connec- 
tion rules should be followed: 

1. Connect a .01 uF disc 
capacitor from the +5 con- 

nection to the ground con- 
nection of each IC, Locate 
the capacitor as close as is 
practical and use short leads. 
A miniature disc with a 
voltage rating of 10 volts or 
more is a good choice, 

2. Use fairly heavy wire {1 
recommend #1 8 or larger) for 

+5 and ground lines and 




96 



INPUT 




JNPUT I 
INPUT Z 




Fig, Z Standard TTL input Fig. 3, Input circuit of 
circuit, 2-inpu l gate. 



arrange them so ihere are 
many connections. Try to 
simulate a ground plane and a 
+5 plane. 

3. For every 20 ICs or so 
in your circuit put in one 
electrolytic capacitor from +5 
to ground. Any value 
between approximately 4 and 
25 uF and 10 volts or more 
rating is OK. If only one is 
used, try to locate it where 
the +5 first comes onto the 
board. If more are usedj 
distribute them more or less 
evenly over the board. 

4- Use a regulated supply 
for the +5 V, There are many 
circuits for making a regu- 
lated supply. Look at almost 
any article using ICs and pick 
one that suits your require- 
ments. 

Some of the above rules 
may seem obvious while 
others are not so well known, 
especially to the newcomer. 
Fig. 1 illustrates one method 
of construction employing 
point to point wiring follow- 
ing the above rules. 

Next on the list of TTL 
'*ins** let's investigate a 
typical input circuit as shown 
in Fig. 2, In order to guaran- 
tee that the transistor is 
turned on we must do two 
things. First, we must make 
the input voltage less than .8 
V, and second we must draw 
out of the emitter 1.6 mA of 
current. In order to guarantee 
that the transistor is turned 
off we must also do two 
things. First, we must make 
the input voltage greater than 
2 V, and second we may have 
to supply up to 40 uA of 
leakage current. The diode is 
not necessarily present in all 
circuits. Its purpose is to limit 



negative pulses on the input 
that may occur due to trans- 
mission line effects on long 
interconnections. This input 
characteristic is called 1 unit 
load (UL) and a circuit such 
as Fig, 2 which contains 1 UL 
is said to have a fan-in of K 

If a second emitter h 
added to the circuit of Fig. 2 
we have a 2-input gate con- 
figuration, as shown in Fig. 3, 
Each input has its own pro- 
tection diode. If either input 
satisfies the "on" require- 
ments the transistor will be 
on. Obviously, both inputs 
must satisfy the **off' 
requirements in order to turn 
the transistor off. By adding 
more emitters the manufac- 
turers make multiple input 
gates. The 7430, for instance, 
has 8 emitters. 

What about the undefined 
area of the input charac- 
teristic which lies between .8 
V and 2 V? It is just that, 
undefined. This is a "grey 
area** where nothing is 
guaranteed and, except for 
some special circuits (dis- 
cussed later), it should be 
passed through as quickly as 
possible (less than 200 ns). If 
the input passes through this 
region too slowly the output 
can actually break into 
oscillation. In fact, this is 
how a TTL oscillator gets 
started: by being biased 
deliberately into this "grey 
area" until oscillation occurs 
and then having the fre- 
quency of oscillation con- 
trolled by external com- 
ponents. 




Fig. 4, Using a normal switch 
to drive TTL. 

themselves very nicely, but 
the outside world is not 
necessarily TTL compatible. 

How do you satisfy the input 
requirements outlined above? 
It is very easy to get a voltage 
less than .8 V and able to sink 
1.6 mA: Just short the input 
to ground with a switch. 
What about the other limit? 
How do we get the high 
voltage and current source? 
Fig. 4 shows one way. The 1 k 
resistor guarantees that even 
with 40 uA being drawn, the 
voliage will be above the 
required 2 V minimum. 

When the input is rela- 
tively slow in changing you 
can avoid the *'grey area" 
problem by using TTL ICs 
which have a special 
hysteresis built into them. 
These are called Schmitt 
triggers and have different 
switching points depending 
on whether the signal is posi- 
tive or negative going at the 
time. The 7413, 7414, and 
74132 are examples of this 
Schmitt trigger type of 
circuit* 

When considering switches 
as the connection to the out- 
side world another potential 
problem arises. The contacts 
of the switch don't close 
'*cleanly/' They actually hit 
and bounce apart one or 



more times before remaining 
closed. Normally this is no 
problem, but if you were 
attempting to count switch 
closures it would not be 
possible. Fig. 5 shows how to 
use an SPDT switch and two 
NAND gate elements to form 
a flip flop which debounces 
the switch. This is a very 
common form of circuit con- 
figuration called cross- 
coupled NAND gates. 

Often when you are 
finished with a logic design 
you will find yourself with 
unused inputs to some 
circuits. Never, repeat, never 
leave any unused input to 
float; it will cause nothing 
but trouble. Even though an 
open input is theoretically 
the same as a high, in practice 
it is very sensitive to any kind 
of noise and can cause the 
output to change for no 
apparent reason. 

What do you do with 
unused inputs? There are 
several choices: 
T If it will not prevent 
normal operation of ttie cir- 
cuit you can ground the 
unused input or connect it to 
a high source, 

la. The high can be 
obtained by connecting 
directly to +5 V. The 
manufacturers don't 
recommend this since, 
if the input goes above 
+5.5 V, it is possible to 
damage the input if the 
current is not limited in 
some way. I do it all 
the time with no pro- 
blems (yet). I recom- 
mend connecting to the 
+5 V connection on the 
chip itself. 

lb. Connect the un- 
used input to +5 V 



Inputs 
World 



from the Outside 



circuits connect to 




THIS IS HIGH 

FOR SWITCH 

POSlTtOM 
SHOWM 

THIS IS LOW 
FOR SWITCH 
POSITION* 
SHOWN 



Fig. 5. Using cross<oupled NAND gates to 
debounce a switch. 



97 




IWPUT CLOCK 

OUTPUT OF EDGE 

TRIGGERED 
FLIP-FLOP 



OUTPUT OF 

MASTER -Slave 

FLIP-FLOP 



9CA 



-»■] WPRQPAQAtiOU 
I I J DELAY 



t 



I 

r 

u 



MASTER CHANGES HERE 



Fig. 6. Timing diagram showing difference 
between edge- triggered and master-slave flip 
flops. 



through a Ik resistor. 
One resistor can tie as 
many as 50 inputs to 

lc_ Use an unused in- 
verting element and 
ground the input (s) to 
force the output high. 
This high output can 
then be used lo pull up 
as many inputs as Its 
fan-out is rated (see 
output section), 
2. Unused inputs of gates can 
be connected in parallel with 
used inputs. There is no in- 
crease in load for low inputs. 
The total current required for 
the two inputs in parallel is 
still 1.6 mA. Actually you 
can tie as many in parallel as 
you wish and the total low 
fan-in will not exceed 1 UL. 
The high fannn does increase, 
however, as each emitter may 
require the 40 uA leakage 
current. As long as the high 
fan-out capability of the 
driving cirojit is r^ol exceeded 
you can parallel gate inputs. 
One more input charac- 
teristic of TTL circuits is 
worth mentioning. This is the 
difference between so-called 
edge*triggered and master- 
stave flip flops. The outputs 
of both circuits react accord- 
ing to the status of the con- 
trol lines at the time the 
clock pulse occurs. An edge- 
triggered flip flop output 
reacts essentially imr.ie- 
diately* The small delay is 
called propagation delay. A 
master-slave flip flop is more 
subtle. On the leading edge of 
the clock pulse the master 
reacts like an edge-triggered 
flip flop. The output, how- 
ever, is from the slave and it 
does not react until the 



trailing edge of the clock 
pulse» Fig. 6 shows this 
difference in graphic form. 
The main point to remember 
is that a master-slave flip flop 
requires a complete clock 
cycle, not just one edge. 

Outs 

There are three basic 
forms of output circuit used 
in TTL, The most common 
form is shown in Fig. 1 , This 
Is the so-called totem pole 
configuration. In the low out- 
put state the bottom tran- 
sistor is on and the top tran- 
sistor is off. The bottom tran- 
sistor sinks the current from 
the connected inputs. In the 
high state the bottom tran- 
sistor is off and the top 
transistor is on. The top 
transistor now supplies the 
leakage currents for the con- 
nected inputs. This Is the 
norma! version. There are 
minor variations on this 
circuit but they all operate 
the same way. 

The number of unit loads 
an output can drive is called 
its fan-out* The standard TTL 
IC has a low fan-out of 10 UL 
and a high fan-out of 20 UL. 
In other words, a standard 
TTL output can sink 16 mA 
(10 times 1.6 mA) and the 
output is guaranteed to be no 
hi^er than A V or it can 
source 800 uA (20 times 40 
uA) and the output is guaran- 
teed to be higher than 2.4 V* 
If you compare these output 
specs with the input specs 
you will find there is a .4 V 
safety margin. 

There are several ICs 
which are specifically de- 
signed to drive larger loads. 
The 7437, 7438, 7439 and 




TOP 
TRANSISTOR 



OUTPUT 



BOTTOM 
TRAfVSiSTOR 



Fig. 7. Totem pole TTL 
output circuit, 

7440 will all sink 30 UL, The 
7437 and 7440 will also 
source 30 UL. 

The 7438 and 7439 belong 
to another class of output 
circuit called *'open collec- 
tor." In this configuration the 
top transistor is missing and 
the bare collector of the 
bottom transistor is brought 
out. With this circuit you 
need an external load resistor 
of some sort to provide the 
pull-up to +5 V. If the voltage 
rating of the IC output is high 
enough (the 7407 is rated for 
30 V, for example), you can 
switch much higher voltages, 
and even drive relays and 
lamps if the current rating is 
not exceeded. 

The open collector circuit 
is also used in a logic con- 
figuration known as both 
"wired-and'* and "wired-or.** 
Fig, 8 shows how this works. 
All the open collector 
outputs are tied to a common 




pull-up resistor. If any output 

goes low they all go low 
{wjred-or), and the output 
wil! only be high when all the 
output transistors are off 
(wired-and, hence both 
terms). There is a practical 
limit to how many outputs 
you can connect together. 
The pull-up resistor must 
supply the leakage current for 
all inputs and all outputs 
when they are all off and still 
maintain the voltage above 
2.4 V, However, it must still 
be large enough to limit the 
total current of resistor plus 
inputs to 16 mA (10 UL) 
when any output is on. 

Contrary to what you may 
have read previously, it is OK 
to connect TTL outputs in 
parallel i provided you also 
connect the inputs in parallel 
so the outputs are doing the 
same thing at the same time. 
In fact, the manufacturers 
recommend this technique as 
one way io increase fan-out 
when the load is too much 
for one output. However, you 
should restrict this paralleling 
to elements in the same 
package because large tran- 
sient currents are generated 
and can cause problems if 
they are not closely confined. 

The third and newest type 
of output configuration is the 
so-called tri-state or 3-state 
output. This is a normal TTL 
totem pole output where 
both transistors can be turned 
off. An extra **enable" input 



RESISTOR 

SUPPLIED 

LEAKAGE 

CURRENT 



N UL 

CURRENT 
IF ANV 
OUTPUT 
IS LOW 



•n 



U INPUTS 
£ACH I UL 



Fig, S. Using open collector outputs for 
wired-or configuration. 



M 



98 




360 fl 

bmviwuM 



OPEN COLLECTOR 
OUTPUT 




o 



56012 
MINIMUM 




NORMAL OUTPUT 



Fig. 9, TTL driving transistors, 

is added to the circuit and 
when enabled the output 
functions as a normal TTL 
output. When disabled the 
output is essentially discon- 
nected. This allows one com- 
mon wire with many tri^state 
outputs connected to it to 
carry all sorts of different 
information (even in different 
directions) on a time division 
multiplex basis. All you have 
to do is enable the appro- 
priate outputs and inputs at 
the proper time. This *'bus 
structure'* is very common in 
the world of computers and 
microprocessors. I have used 
tri-state circuits to latch 336 
bits of data at one time and 
then output them 8 bits at a 
time. That is 42 different 
outputs on each data line. 

Someplace in your design 
you have to connect outputs 
to the outside world. There 
are special ICs for driving 
displays of different kinds as 
this is one of the most com* 
mon outputs encountered. I 
have also mentioned using 
high voltage open collector 
outputs. If you need more 
current or voltage, you can 
use a circuit such as shown in 
Fig. 9. In boLh versions the 
resistors limit the base 
current to a safe value. When 
driving an external circuit of 
any kind it is best to use an 



♦ 5 



output dedicated to only that 
load. That way, if any stray 
signals are picked up and fed 
back on this line to the out- 
side world they won't be able 
to couple into another Input 
and disrupt operation. Also 
you should never use the 
output of a flip flop (this 
includes counters, shift 
registers, etc.) to connect to 
the outside world. It is too 
easy for a stray signal to 
sneak back, get inside the flip 
flop, and do weird things. 

When ii becomes necessary 
to switch large output loads, 
often there are transients gen- 
erated that ride back in on 
the ground and cause stray 
triggers of flip flops and other 
nasty things. A relatively new 
circuit element called an 
opto-isolator eliminates this 
problem completely. Even 
when driving all 8 channels 
plus sprocket advance of a 
high speed paper tape punch 
there is no problem — and 
that represents 9 A at 24 V 
every 9 ms. The opto-isolator 
(see Fig. 10) consists of an 
infrared LED and photolran- 
sistor. The LED is driven 
from an open collector 
output and its energy is 
coupled optically {no 
physical conncciion) to the 
phototransistor, which is then 
used as a low level switching 
stage in a totally electrically 
isolated circuit. 

The preceding rules and 
suggestions will not eliminate 
all your digital logic problems 
but they will greatly reduce 
them, especially those 
frustrating random ones. 
Remember the manufacturers 
only guarantee proper opera- 
tion if you stay within the 
specs. Exceed the specs and 
all bets are off, ■ 



rson 

MINIMUM 



o 



l6inA 
MAX 



OPEN COLLECTOR 
OUTPUT 




TYPICAL 
ESTIMATE 
10% TO 20% 

OF Diooe 

CURRENT 



Fig. JO. Using an opto-fso/a tor. 




I 



Ti^pkil EQaipane^nt co-il deluding IS TTL land B Cmoi chips is S4G plui p/c boird. 

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Write to Dave (K6LKU at 

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P.O. Boh 9160, Stock loni CA 95208 



99 




i 



oil goons d 



I i- 




;-EES 



1 i. 



I insist that you print vj 



from page ?5 

the requireffiient to 18 wpm — an 
interesting contrast I 

Another i merest ing note - i Stsrs 
and Siiipes article (I w*^ I'd tdved it) 
of a few weeks ago told of ihe iHavy 
liaving troyble coordinating with an 
alliecf nation's navy because none of 
the navy radiomen could handle CW — 
and the foreign navy didn't have our 
fancv RTTY and digital equipment] 

At any rate, congratulaiions on a 
great magazirve, Wayne, and I hope 
you get the bugs caused by the size 
change worked out soon. 

Hartley J. Gardner WA1KMG/DL 

APONV 



ZL CHANGE 

Please note change of address fof 
the New Zealand QSL Bureau: P,0. 
Sox 40 212, Upper Hutl, NEW ZEA^ 
LAMO. 

G. C Black well ZL3NT 
General Secretary 



DOING YOURSELF OUT 

I thougfit I would enck)^ a quick 
note along with my readet ^fvic^ 
requests to tell you what a great mag 
you put out. Anyone with an interest 
rn amateur radio, and with your new 
section on microprocessors, would be 
doing himself out of a great deal o1 
enjoyable reading by not subscribing 
to /3. Keep up the good work, 

Bruce McCreath VE3EAR 
Goderich ONT 



TO THE TROOPS 

Got my brand new fonriat 73 
yesterday over here Bt APD 091 89 
{southwest Germany), and t must say 
tfiat I am impressed! I really like the 
new size, everi though I was skeptical 
when I first heard that you were 
switching oyer 

f^eally a nice idea to have the Heath 
and the Hickok catalogs within the 
same covers. The new 73 is even 



better than before, and 1 have taken 
steps around my house to convert my 
bookshelves ovet to the new 73, I 
appreciate the skill and prepLanning 
that went into your conversion as per 
page 3, 

Kinda feel for d guy like Fred 
Lichtgarn who is quitting before 
starting, 

The new 73 made it to my APD, 
and ttwn to me, in beautiful condi- 
tion, so yai>r mailer system is working 
fine. 

Many thanks Wayne, and to tfie 
troops at 73, vvho continue to keep 
better and better 73s asming this 
way I 

5SGT Howard H. Ragan 

K7ATU/DA4AU 

1141-2 USAFSAS 

APO NV 09189 



AIR BLUSH 

t am wTFting to c3onf!rm your claim 
for the efficacy of your t^es (codeK 
They have worked for me. I cannot 
truthftilly give you the exact number 
of Kours I used the 5 wpm tape, but I 
win approxirn ate it at 6 hours, over a 
period of a few weeks. After that 
time, I joined a ham radio cla^ at 
Cerritos College, Cerritas, California. 
The instructor, Roy Tucker KBUZB, 
has his own code tapes to loan to the 
students. I tried his and found tfiem 
too simple, since after five weeks of 
class sessions I passed the test run fof 



the fSiovJce code, I believe tf^t it was 
my previous study of your tape that 
made this possible, pitis the fact tftat I 
am a mustcian and am quite accus^ 
tomed to listenirKj for rhythnm and 
memorizirfg them. It was not difficult 
for me at all I am presently working 
on upgrading to a General license 
(hopefully) and am just startir^ on 
the 13 wpm tape now. I will attempt 
to keep a check on the length of time 
it takes to achieve this speed. You 
may atso find it interesting to know 
that Mr. Tucker uses the same prin- 
ciple tl^t you do of rea>rding the 
code character at 13 wpm and 
increasing the spacing betv^en for 
ease of identification. He adds the 
device of naming the letter it repre- 
sents. This is good at the start, but 
becomes irksome. 

There is something etse on my 
mind, Wayne. I feel I have something 
to say to your readers from the point 
of view of a white, female Caucasian^ 
preseiTtly 53 years of age, married, the 
mother of two girls, and a successful 
pianist and teacher. I was dragged into 
this radio thing by my fiu^Mid, wtto 
was formerly a ham and bad dropped 
It as a young man. My attitude was 
pretty bad — tbe best you could say 
about it was that I was ambivalent and 
coufdn't see the point of it for myself. 
It was obviously good for my hus- 
band, and I was touched thai after 16 
years of marriage he still wanted me 
to share his interests. I simply 

Conttnusd Of} p^ge f54 



The ONLY QSL Bureau that will forward ALL 
of your cards . . . from anywhere to anywhere - 
Still S.06 for DX cards . . . S.IO intra-U,SA and 
Canada . . . SASE brings details. 



DX'ERS SPECLAL - For QSL$ to Foreign stations 
only. Send 20 or more cards at a time and include just 
five cents &ach! For 100 or more cards at a time the 
price is four cents e&ch^ 

Suggestion; Form a CARD POOL with your Buddy or 
Radio Club and split the extra savirigs. 

73s Orm Meyer K6QX 



111 FARM HILL WAY LOS GATOS, CALIFORNIA 95030 U.S.A. 



WORLD 

QSL 

BUREAU 



m 



mlM 




nii/tn SAv die 



from page 4 

charge admission to the same party 
... or you may not. 

Be sure to have someone with 
imaginatior* and some business ex* 
per ience with relatively large sums of 
money irwolved so you don't penny 
ante the ham f est. You are working 
with thousands of doUa<rs, so you 



de W2nlSDll 



ORiAL BY WAVNE GHEEN 

can't afford to be too sttngy on 
things. If you pull it of I well, you will 
be able to keep the hamfest going year 
after year, buitding yp in displays and 
ha mf esters. 

How about some articles on 
successful hamfest 5 lo spur Interest in 
this activity? 



VHF ENGINEERING 
Bob Brovm W2EDN, just back from 
or>e of th»e Windjammer cruises of the 
Caribbean, is really hot tor a good 
design engir>eer to hefp him work up 
some new products. If you know of 
anyone wtws likes to do that sort of 
"work/* harve ifiem get in touct) with 
Bob, Bob ts looking for someor>e with 
a lot of background in PC board 
layout and design . . . and he's got a 
darned good salary ready for some- 
one. The Binghamton area is a nice 
one . . . 

I gather that Bob and his family 
enjoyed the cruise . , . we've been 
advertising them in 73 off and on and 
hid quite a few enthusiastic letters 



and calls from happy cruisers. They 
are strictly informal and low key . . . 
aimost do-It yoursetf vacatbns. 

73 IS LOOKING. TOO 
We're still tn need of someone with 
a good ham background to help put 
together books. A good technical 
background will help vs will an ability 
to write. And New Hampshire is even 
better than Birtghamton for living. 
You could do worse. 

As long as you have to work for a 
tivirhg, why not work in your majof 
hobby 3r>d enjoy every minute of it? 
And as iong as you have to live, why 
not live wfiere others come for vaca- 
tion all year 'round? 



100 



Stay tuned for future programs 




The HAL ST-6000 demodulator 
/keyer and the DS-3000and DS-40O0 
KSR/RO series of communicalions 
terminal are designed to give you 
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The HAL ST- 6000 operates at 
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Active filters allow flexibility in estab- 



lishing different tone pairs. You can 
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The ST-6000 has an outstandingly 
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Data I/O can be RS-232C, MIL-l^C 
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The DS-3000 and DS-4000 series of 
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m 



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These are some of tt>e highlights, 
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HAL Communications Corp., Box 365, 807 E. Green Street 
Urbana, Illinois 61801 ■ Telephone: (217) 367-7373 



D W.hhnme! WA6VVL 
I US FauMrino A venue 
CosiaMesa CA 92626 



Build 




C W Memory 



White building a random access 
memory (RAM) for my keyer^ it 
occurred to mc ihat my CW operating habits 
did not require the versatility of the RAM 



and that my memory requirements could be 
satisfied with one or more programmable 
read oniy memories (PROMsK 

Although the control logic for the read 



modes are similar for RAMs and PROMs, 
PROMs offer a non-deslruclible memory 
(within their recommended operating para- 
meters) after their initial programming, 



#fi 



ftt 



m 



rt 



m 



rtl 



m 




phoc«ah 



SELECT 



Sm^D ^^ H" 



w^ j 



PO"^^ 







02 



without the need to frequently refresh the 
memory as h necessary with RAMs. 

The memory described is self -contained 
and need not be used with a kcycr. The 
output circuitry is desired to drive grid- 
block keyed iransmttters with key-up 
voltages not exceeding —100 volts. TTL 
inputs are available for keying the trans- 
mitter from an external source {[,e., the 
digital output from additional memories, a 
kcyer, or C\V tden tiller). 

Ctrctlft Descriptiotl 

Fig. I shows a simplified block diagram 

of the PROM memrjr% The memory uses 
four tniersil IM5600C PROMs. These 
PROMs are fully decoded TTL Bipolar 
2S6-bit custom progrann.med read only 
memories organized as 32 words by 8 bits 
(U7-U10). Open collector outputs and chip 
enables insure simple memory expansion. An 
effective memory capacity of 1024 bits Is 
obtained by ORing the four 256-bit chips 
together. I chose a 256-bit PROM because it 
offers a convenient memory length of 
approximately 22 characters. Memory 
retrieval is initiated with the appropriate 
program select push-button switch (S2-S5). 
The program can be stopped at any point 
with the stop push-button switch {SI )- 

U3 and U4 are 7476 Dual J-K flip flops 
with preset and clear, used as start/stop flip 
flops. The stop pushbutton switch, SI, is 
connected to the preset inputs (pins 2 and 7) 
of LI3 and U4. Grounding this bus forces the 
outputs to logic I, disabling the clock and 
U6, stopping I he program (a logic 1 on pin 7 
of U6 forces pin 5 low). The clock Inputs 
(pins 1 and 6) are connected together. A 
negative edge at the clock inputs, corres- 
ponding Lo the end of the 2S6th bit, will 
clock Q to logic 1, disabling the clock and 
U6, ending the program. Individual program 
select switches are connected to the clear 
inputs (pins 3 and 8) of U3 and U4. 
Grounding one of these pins will start the 
program corresponding to the PROM 
selected. The Q outputs of U3 and U4 (pins 
1 T and tS) are connected to the chip enable 
inputs (pin 15) of the four PROMs. The 
appropriate PROM is enabled by forcing one 
of the outputs of U3 or U4 to logic 0, 
enabling the clock and U6, starting the 
program. Starting the program resets the 
efghi bit binary address counter Ul and U2. 

U1 and U2 are 7493 TTL MSI 4-bit 
binary counters used to address PROMs 
LTZ-UIO and U6, a 74151 TTL MSI 8-line- 
to-I-line data selector. The first three bits 
from the counter address U6» while the 
remaining bits address PROMs U7-UtO. In 
this fashion U6 multiplexes the PROM 
outputs of eight lines to one line before the 
address counter selects the next word. 

US is a 7420 TTL Dual 4Hnput positive 
NAND gate. It is the enable/disable gate for 
the clock and U6 and the reset gate for the 
eight*bit binary address counter* Ull is a 
7403 TTL Quadruple 2-input positive 



> 



EXTERNAL ^ 
DIGITAL > 

INPUTS y 



KEYING 
CIRCUITRY 

(7403,04) 



TO TRANSMITTER 



I 



PARALLEL TO SERIAL 

CONVERSION 

(74151) 



CLOCK 
(01,02) 



TTTl 






PROM MEMORY 
(fM5600C X FOUR) 



z — f — f — f 



ADDRESS COUNTER 
(7493 X TWO) 



J 



CHIP ENABLES 



DISABLE 
LINE 



START/STOP FLIP/FLOPS 
(7476 X TWO) 



NO. I — START N,0, L^ STOP 
Fig. f, B/ftck diagram of the PROM CW generator. 



NAND gate with open collector outputs 
used as the input for the transmitter keying 
circuitry. 

Clock pulses for the memory are 
generated by a relaxation oscillator con* 
sisting of 01 and Q2 and associated parts.' 
The oscillator is the same one used in my 
keyer and was selected so that the speed 
controls could be ganged and would track in 
the event that the keyer would be packaged 
with the memory (it wasn't). 

Programming 

PROMs are fabricated with all logic levels 
at zero. The programming procedure open- 
circuits metal links which results in a logic 1 
at selected locations in the memory. Intersil, 
instead of using a metal link^ forces a 
resistive shaft through the [unclion of one 
diode in the memory cell resulting in a logic 
1 at selected locations in the memory. Once 
the memory cell has been pro^ammed to a 
logic 1, that bit cannot be altered (repro- 
grammed). 

Distributors of PROMs offer cttstom pro- 
gramming services or the reader may 
program his own. Design data sheets and 
application notes describe the programming 
procedures in detail.^ Read these instruc- 
tions carefully and fully understand the 
address methods as programming errors can 
be costly. 



Fig. 2 illustrates a typical programming 
card for the fol[ owing program: DE 
WA6VVL WA6VVL WA6VVL K. Standard 
spacing should be used in writing the pro- 
gram. For example, use 7 bits for a word 
space, 3 bits for a letter space, 3 bits for a 
dash and 1 bit for a dot. 

The quoted price from R.V. Weatherford 
included programming costs. One advantage 
of a distributor programming your PROM is 
that they verify its program before they send 
it to you. 

Power Supply 

The 5 volt supply illustrated in Fig. Scan 
be built to satisfy the requirements of the 
memory circuitry* U12 should be mounted 
on a heat sink similar to the Wakefield 
680-J5Aor621'A. 

U12 dissipates only \h Watts at nominal 
line using a 6,3 V transformer. However^ at 
low line, ripple feeds through the regulator. 
No problems with the memory have been 
experienced under low line conditions to 
date, A slight improvement in low line 
operation can be gained by using a 12.6 VCT 
transformer and a full wave center-tap 
rectifier. 

If you anticipate using your keyer with 
this memory J do not attempt to power the 
memory circuitry from your keyer power 
supply unless it is capable of supplying an 



103 



M 




weaTHeRFORD 



FAe program is selected with the approprwte program sefecl pash-butlon switch A, B, Cor 
D, The program can be stopped ai any point with the stop push-button switch. A single 20k 
speed control can be used and the HI/LO switch deleted. 




H- 1 


mm 


»T 


Si 


H »J H ^ «t 




c 


H 


- — 




• C2 = ^ 


1 


T 


— i 






E=i z^ a .: 


i 


1 


' a 


^ 


m. =j1 


E=! C3 r= 


1 


} 


=3 


•^ 


■ M ^ ;^ n ■ 




* 










% 


B 


=D 






* 


\m 


C3 


E=9 i:^ M :^ M 



1 ' 


. 


^D 


^^\m 


O C3 :iJ 


* 


« 


a 




M fll t:^ 


u 


« 


^_i 








11 


H 


cz. 


C3 O 


C 


^ ^T a 

■ 


1 


iS 1 


B 


Ml 


C^ 




■i HV O ^ 




LI 

■1 


■r 


B 


m o 






14 


H 


i=. 


B M 




O O £=t 




IS 


LJt 


LJ 


M JS 




a ™ cz 




1« 


« 


n 


B o 


S 


a • — 




17 


M 


□ 


<■ cz 


1 1 


c^ m m 




16 _l 


a 


& 




^ 


B ap =: 




W 


« 


n 


« B 


m 


c • n 


1 


to 


D 


a 


in a 


a 


=. « r- 




tl 


ai 


^ 




■ 


a B r:9 




tl 


■■ 


o 


■ C3 


o 


a W M 




St 


1 '^H' 


V 


■ C3 


o 




4 


14 


m 


D 


■ B 


m 


cr B c: 




n 


« 


= 


^ __ r 


cz: IZ3 c? 




M 


:^ 


C5 








V 




S 


■ =] ■ 


^ B 1^ 




aft 


« 


■ 




i= ^ 




it 


^ 


^ 




!=! B = 




3D 


u 


^ 


H W' =3 


C3 £3 Z= 


i 3. 


r-r 


= 


^ »" «l 


B C^ B 



ON 3 



^ OQl 



Fig. Z Programming card (65%), The ahoye 
program, DE WA6VVL WA6VVL WA6VVL 
Kf Is read from right to left^ top to bottom. 
The program Is written In the same fashion. 



U12 is shown mounted on its heat sink. The two open-circuit phone jacks are connected In 
paraiielf providing an input far the author's keyer and an output for the transmitter. A tine 
cord and grummet may be substituted for the 115 V ac connector. 



addUional 450-650 mA. 

Construction 

The memory is housed in a Cal Chassis 7** 
X U" X 2" aluminum chassis base. The 



malority of the nncmory components are 
mounted on a singlc-sided S'' x 5" glass- 
epoxy circuit board. The board is fabrica led 
to fit a standard 22-ptn card edge connector. 
Since the memory ulilizcs four PRO Ms In 



< Ay 



®I/2A 




O 1 1 



LED 

U5VAC 

Fig. 3. Power supply. *Se/ect for appropriate current through LED selected. 150 Ohms was 
adequate with a Hewlett-Packard 5082-4440 LED, 



Weathertord 
pyROM 

Pl09l9lllill9 Cflra 

Ordulfng (nfofirvillgfi 

1 C^tnpmnf nam* B^ PJ _ T ^hfflP f^l 

Ave. ,Cf^y:t?> d!6ga, Calir 



r OwHd pric« pu P/Hou t^^fK) 

I ftpgunrtiprtf^ cwirhwn oi^irniiHi<bf_^ 
ft SPK4M P/nOU mmT^ang kmneikamjJ^ 



fO.^ SAipiping MMt nirtiry j j ^' ^ . 



HiMF to WM ttito cvv 

t. Um m tsU amncti (Wo. 2 1 

1, ^ li« -prQ«i*Bi ' tl^A bI fwr tmtt RW^ U«A« VMH ttf 

"1" ifm-eil ig«;"ii(m 
4, E)D PlOT EIJ^ In i!m ^nA^iAid JbTb-UI pqMlstl. tl m mtrat 

a. Qn Mid Mo. f Dp •■mi progfXin, c^mel^lt l¥m "Qpttur^ni Inl^r- 

Hs«1<4>i" AfrElJEin kbQW. 
4, hell cjiili with t\\M bitUng Id iveld d«rn4p«r 

Tik« cQinpt«l9d! Clltfi to your noirati Waithorford 
ttitt Qtli£4 or land lo: 
Witlharlard Pf t^gnmlng Cnnltr 
1921 Sen Famsfida H± 



M 



TfH 




SYSTEM 21 DATA MANAGEMENT STATION 

VIATRON'S Sysiem 21 is a family of data processing devices designed for data management, bicluding data entry, control, 
display, communication, storage and retrievaL With its modular structure, System 21 can be configured to perform a wide 
variety of data processing operations. 

A typical System 21 configuration includes a Microprocessor, two Tape Charmels, a Keyboard, two Data Channels, and a 
Video Display, Central to the System 21 structure is the Microprocessor which contains hard-wired microprograms that 
perform a fixed set of logical operations. The hard-wired microprograms in the Microprocessor accomphsh the same 
functions as a general-purpose computer operating system or assembler. Because the microprograms are hard-wired, 
however, there is no need for extensive programming. 

There are two modes of system operation— manual control and program control. In the marmal mode of operation, the 
operator initiates all Microprocessor functions. Under program control the Microprocessor performs certain functions 
automatically through the use of a control program. 

The Microprocessor has four input/output channels, two Tape Channels and two Data Channels, The Tape Channels are 
devoted to either VIATAPE Recorders or Computer Tape Recorders, one recorder per channel. The two Data Channels 
can communicate with optional input/output devices. They can be connected, for example, to a Model 6001 Card 
Reader/Punch Adapter for reading and punching cards, or to a Model 6002 Printing Robot for providing hard copy. The 
Data Channels can also be interfaced with a Model 6003, 6004, or 6005 Communication Adapter for providing a link with 
another System 21 Data Management Station, a computer, or virtually any other device capable of USASCII interface. The 
Keyboard has its own Channel dedicated to providing data input and control to the Microprocessor, 

Unused, packed in 4 cartons. System consists of video display, power supply, microprocessor, two cassette tape decks 
mounted in microprocessor panel, keyboard, all as pictured. Sold ''as is." Due to 4 years of storage, may require some 
adjusting/cleaning. With instruction book. Shipment within 24 hours if paid by MC, BA, or certified check. Sold FOB 
Lynn Mass. 



e^nMd 



$ 425 oo 



MESHNA PO Bx 62 E. Lynn Mass. 01904 



m 







Parts List 




CI 


4.7 mF TO W V dc tantalum capacitor 


R12 


2700 Ohm % Watt carbon resistor 


C2 


,001 mF ceramic capacitor 


R13 


10,000 Ohm 2 Watt linear taper potentiometer 


C3-4 


4700 mF 1 6 W V dc etectrolytk capacitor 


R14 


82 Ohm % Wart carbon resistor 


C5 


.33 mF ceramic capacitor 


R25 


1 0,000 Ohm !4 Wati carbon resistor ' 


C6 


2.2 mF 10 W V dc tantalum capacitor 


SW1'5 


Mormatly open pu$h'button switch. Similar to 


C7 


,1 mF 1 W V dc ditsc ceramic capacitor 




Alcofiwiich MSPS 103C SPST, 


CR1 


1 N914 silicon signal diode 


SW6 


DPST miniature roqker switch. Similar to 


CR2-5 


1N4001 or equivalent SO V piv rectifier diode 




Alcoswitch MSL-203N-7. 


Ql 


2N5086 or equivalent PNP transistor 


T1 


6,3 V ac Filament Transformer, 1 A. Similar to 


Q2 


2N&961 or ^uivalent NPN transistor 




Allied 8K9HF or Triad F-14X. 


Q3 


2N5224 or equivalent NPN transistor 


U1-2 


/4d3 1 I L MSl 4'tnt Dmarv counter 


Q4 


2N4&^ or equivalent HV PNP transtsior 


U3-4 


/4/t> 1 1 L Dual J- K flip Hops with preset and clear 


RMRS.ftiG 


470 Ohm ^>^ Watt carbof^ msistor 


US 


7420 TTL Dual 4-inpuT positive MAND gate 


HBJ^b^7-24 


4700 Ohm Vi Watt cartson re^istof 


U6 


74151 1 T L MS! 84ine^tO'T-tine data selector 


RS 


22 Ohm % Watt carbon resistor 


U7I0 


Intersil IM5600C 2564jit PROM 


R9 


27,000 Ohm Vt Watt carbofl resistor 


U11 


7403 TTL Quadruple 2- input positive NAND gate 


RIO 


39,000 Ohm % Watt carbon resistor 


U12 


?80S or LM309 Three terminal regulator 


R11 


15,000 Ohm !^ Watt cartion resistor 







parallel on a single-sided board^ there arc a 
number of jumpers (92) and holes (434) on 
the circuit board. The jumpers are Installed 
first with ihe rest of the components foilow- 
ifig. Sockets arc advisabte due to the cost of 
the integralcd circuits and PROMs. They not 
only speed troubleshooting when the need 
arises, but also prevent overheating during 
the soldering operation. The power trans- 
former, filler capacitors, regulator, panel 
switches and controls are mounted on the 
aluminum chassis* 

Total assembly time for the board, 
including drilling the holes, was under 4 
hours. Mechanical and chassis wiring con* 
sumed another 10 hours. 

After assembly, connect ptns 1 and 20 



Pin Assignments 

t TTL input. Logical 1 {-^2.5-5.25 VJ will kefy 
transmitter. Ground! rf nor used. 

2 TTL input. Logical \ t+2J-5.25 V| will key 
transmitter. Ground tf not used. 

3 TTL inpu!. Ugical 1 (+2.5-5.25 V) will key 
transmitter. Ground if not u*&ti. 

4 TTL input. Logical 1 (+2.5-5.25 VJ will key 
transmitter. Ground if not used. 

5 A spare ~ May be used lo ejciernally enable 

6 e spare the PROMs tnitead of U3 & U4, 

7 C spare or connected to the chip enables 
6 D spare ^ fo drrve external LED displays. 

9 Kwfer output. Designed to drive ti^ansmitters 
utilizir>g negative grid-block keying. The PMP driver 
transistor specified will wiihsiand —100 volts 
under key -up conditions. Do not use with cathode 
keyed transmitters. 

10 Digital output. Do not use for keying trans- 
mitter. Output is low as transmitter is keyed, 
Logical 1. +2.5-5.25 V. Logical 0, to + A V. 

1 1 NX, 

12 N.a 

13 Starr program A. Momentary cxintact closure 
to ground lo Start. 

14 Start program B. Momentary contact closure 
to ground to start. 

15 Start program C. Monnaniaty contact closure 
to ground to start. 

16 Start program D. Momentary contact closure 
to ground to start. 

17 Stop program ABCD, Momemary contact 
closure to ground to stop. 

IS To speed control 

19 To speed control. 

20 Memory digital output. Do not use for 
keying transrnitters. Output ti high as transmitter is 
keyed. Logical 1, +2.5-5.25 V. togjcal 0. to +,4 
V. 

21 DC voJts input. +4.75 V to +5.25 V, 

22 D^gita^ Ground. 



together on the connector* This connects the 
digital output of the memory to the first 
input of the transmitting keying circuitry. If 
there are no additional inputs, ground pins 
2, 3 afid 4. 

After checking the power supply voltage, 
connect the power supply^ start/stop push- 
buttons and speed control, and the memory 
IS ready for use. 

Two open-circuit phone jacks have been 
provided on the rear apron of the chassis. 
They are connected in parallel providing an 
input U)\ my keyer and an output for the 
transmitter. 

Turn the PROM mcm<M"y on "off the air*' 
as it wti! take a few seconds for the men^iry 
to clear itself, the actual lime dependent 
upon the selling of the speed control. 

Alte ma lives 

If the reader was not satisfied with using 



the PROMs selected in this article^ there are 
a number of PROMs available from which 
the reader could choose, Texas Instruments, 
for example, offers the 74186 (512-bit, 64 
words by S bits}, 74T87 {1024-bit, 256 
words by 4 bits) and the 741 88A (256^bii, 
32 words by 8 bits). There are pin- 
compatible equivalents available from other 
manufacturers. The Intersil IM5600C is pin* 
compatible with other 256-bit PROMs 
including the Texas Instruments 741 88A 
and Signetics8223. 

If the reader was reasonably sure that his 
program would not change, the 1024-bit 
PROM might be a better choice with simpler 
supporting Ipgjc. Additional benefits include 
less than 2^/bit {compared to about 2Vi^/blt 
for 256-bit PROMs) and one third the board 
area. One possible disadvantage is the eight 
programming cards which need to be filled 
out. 




777/s PC board Is the protoiype version, fhe revised board has two additional jumpers. The 
f titer capacitors are mounted under the circuit board, C3 is partiaiiy visible. C5 and C6 are 
connected directly ta UJ2 and ore not visible. 




106 




Fig. 4, PC board (full size). 




Fig, 5, Component layout. 



107 U^ 




^ 



STOP 
ABCP 



GROUND 



<P1N22 



SW2 





LOF 


fft 


^ 


r^ \ t 


:25 


m 


C2 


lOK 


5K 


.001 1 


► 



PROGRAM SELECT 
PUSHBUTTON SWITCHES 




TO 

TRANS- 
MITTER 



PTN 20 
DI6 OUT 

NC 
STROat 



Fig. 6. Schema! k of the PROM CW genera ior-keyer. 



Conclusion 

The memory described here has been 

designed specifically for my CW operating 
habits, Miiny variations in construction, chip 
enable and address circuitry, memory size 
(bm), and PROMs are possible. 

Utiing my board, total construction costs 
should noi exceed $60,00 assuming the 



reader had to purchase all the parts. Approx- 
imately 40% of the cost is for the PROMs. 

I would like to thank Alan BLirg^uhttT 
WA6AW0 for providing negatives and proto- 
type circuit boards while developing the 
memory. ■ 

' James Garren WB4VVP, "The WB4VVF Accu- 
Keyer/* QST, August, 1973, pages 19-23. 



Designing with TTL PROMs and ROMs from 
Texas lostrumenis. Bulletin CS062. 

Addilional References 

The Weatherford Universat P^ROM Programming 

Center, BulleTin W2123. Weatherford, 6921 San 

Fernando Rd., Glendale CA 91201. 

tmersil JMSeOOC Data Sheet. 

IniersJl IM560Q Reliabiliiy Evaluation Data Sheet. 

Tim TTL Dsts Book For Design Engitieen^ Texas 

Instruments Incorporated. 



M 



^m 




N6W 




.dfi 



nmrmim 



Series 1750, 1751 
Display IVIounting Hardware 



IHatAU^D VIEWING SCR££N 

SEnJES tTSO 



i I^ 



x: 



Ma 

J12.1fl^ 



1— y^ 



J 



^ 



(H^l 



iHSTfcLUU VIEWING SCRttN 

9ERa£S 1751 



/ 




/ 



1 J9y 



Ma I dad socket block gccepts ston-dard 7 segment LED read- 
outs wUh ,3" row spacing. Pins are ,65" long wire wrop 
Jype, Bezel orvd S0H:k«t block ore black molded plosf-ic wath 
viewing screen oval labia in rect, ombar, or smoky neutral, 
c;ir<:iilarly polarized fw glore reduction ^ Untque nnaunHng 
systain Is self fcpstening to pone I cutouts Two jizes avoil- 
oble* 1750 serl&s for uge with up to .4" htgh readouts, 
1751 series for use with up to 1 " hlgb readoufs* 
IMPORTANT! Lest 2 digits of port numbers shown be I aw' 
denote nurr^ar of raodottt positions, (specify screen coiorj 

1750-04,-47,00 1 750-06.,, S9. 00 1750-OB. .$T T.OO 
T7Sl-04„,$7,27 1751 -06.., $9, 31 1751 -OB, .if T. 34 




MINIATURE ROCKER DIP SWITCHES 

Dual Jn-Sine SPST switch arrays for P,C, mounting. Spring 
loaded sliding ball contact system for positive^ ^^oi^ proof 
OOntoCt* Corner in. Contccl' arrangements from 4 to 10 par 
pack* Rti standard DIP sockets. Lost two diglta of stock 
number Indicate number of switch^, 

L^ E ■^F*'-/ [^M< PkJW #VP E>'-^ W D4ad D-fr-ln-PBH H-Aifl-d ^^ > ■-'v 

D1S-76^&07,., ,,,,,,..,,.,$3,75 

OIS-76-BOa $3,?5 

DIS-76-BT0 ,., ,..,$4.35 



^'^^TO 



IC SOCKETS - HIGHEST QUALITY H 

PC Mount ^ + + , Sol der Tai i ■ 

5kt-0802,,3pin,,10/$2,25ls^t-T402,,14pin..lO/$2,40 

Skt-1602, J6 pin, lQ/$2,70|Skt-lS02, ,1S pin, ,10/$4,25 

Skt-2202.,22 pin, !0/$5.5o|skt-2402. .24 pin. . 10/$6,03 

WIRE WRAP TAILS 

SkVT400..l4pin. ?0/$4.50|Skt-1600..T6 prn,,10/S5,O3 



IM6100 CPU, InteRils" 12 Bf^ CMOS CPU chip 
lithe mltroprocessoj' which recog^fzes ttie 
famous P0PS/£ instruction set. Single 
powaf supply, 4-7V @ 400 mjcroamps. 

Now, o new low prfce , ,,, 

Full data packet, ,..«,.»«,,,.«« $4 





LM317 Vottcsge ReguWor. 1 ,5A^ 3 termmo! odjustofcle 
regufator in TO-3 case. Adjust? frofn ■i-T,2V to +37V, 
Complete ovarloEjd protection, ,1% load regolotion, 
«01% /V line regulation ii No need to stiock asaorfed reg- 
uJcitors~|u3t stock resistcrs.,,.,.,.,..... ,,.,,,... $4. 99 




NEW! I ! FROM NATIONAL SEMICONDUCTOR 

The MAI 001 electronic clock module coitibines a mono- 
lithic MOS-LSi clock circuit, 4 digit 0,5" LED display^ 
power supply end Other ossocToted corrtpanents on a single 
PC board to form a complete electronic clock. All you 
add IS Q trOnsfcriTner and switches to constFuct o pretested 
digital clock « Featuresr Clock -radio control; 12 hr dis- 
play; 60Hz operation; powef Failure indicotlon^ bright- 
ness control^ "sleep" and "^snoo^e" timers; olam "on" and 
PM indicators; low cost, compact design, 
MAIQOIA,. *..*,*•,* •With Diograms, ,-,,.,., $16. SB 



^=^C1 




5aY5 



WHY EXPOSE YOUR BODY TO THE ELEMENTS? 
AVOID GEfTiNG SOAKED BY HEGH PRICES 
AND MAILING FEES, SAVE TIME, MONEY, 
GAS ANO COLD REMEDIES. BRIGHTEN UP 
YOUR DAY, SHOP THE TRI-TEK WAYll 1 



\ 



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''' RCil 



P GOLD CHIP 

Linear Inte^grated Circuits 

Brond new process by RCA In which the aluminum metal izotion 
hcra been replaced by gold. The chip Is then hermetEcally scal- 
ed, Whot this meons to you is unprecedented reliability^ and 
unlfonnity* Piostic ports thqt meet mil specs t J 
Tri-Tek is proud to be the first to bring this new level of per- 
formance to you at SURPLUS PRICES- Why buy regrodes??? 

CA301 A. .Improvad, general purpose op-ornp,fl pin dip + , 59^ 
CA307 , , , Super 741 op^amp , 6 pin dip <• * t + ,,,,,,,.. , 52<;l 

CA324. . .Comfjensoted quad op-amp^ 14 pin dip ,,,,,$1,80 
CAS39A, ,1jow offset quad comparator, ?4 pin dip ,, , . 51 » 5^ 
CA741C, , Famous general purjiose op-amp, 8 pin dip,, , 45<; 
CA747C,, General purpose duel op-amp, 14 pin dip ,,,,82^ 
CA74SC , , beterficl ly comFjensotad 741 ^ B pin d i p .,,.,«, + 49<: 
CA1453.. Generol purpose dual op-omp, B pTn dip ,,,,, 69i^ 
CA340T , , Quad slngfe supply (5-1 8V) op amp, 14 pin, , , B9<^ 



Another super buy from RCA. CA555 timer. 6 pin dip ,,, 59t 



8080A 



Improveci, performance version of the F>QpuEar fi-bit micro- 
processor by INTEL.,,,,,...*,,*,,, ,S39,95 



ECU 



llCOd 

T1C24 
nC44 
11C53 
11C90 
95H90 
95H9I 



750MHz High Speed Prescaler , $12,30 

Dual VC Multivibrator, DC-30 MHz,,, $ 3,30 

Rhose/Frequency DetectoF, »,-,r^^:k , . , , J 3 *30 
Voltage Controlled Multivibrotor, l55MHz 4p-63 

650MHsr prescoler. Divide by 10 or 11 SI 9. 95 

230 MHz prescoler. Divide by 10 or 1 1 $10,50 

320 MHz prescoler. Divide by 5 or A, . , $10,50 
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109 



Fred R. Goldstein WA I WDS 
43 Union Si. 
Peterborough NH 03458 



AM is not Dead" 
It Never Existed at All 



Over the years ^ amateurs have used 
various modes of transmission. In the 
pasti the rules and regulations specifically 
permitted types of modulation on certain 
frequencies. Unfortunately, these rules made 
unclear the actual facts relating to modula- 
tion. Best use of the spectrum requires that 
we sekct our modes of transmission care- 
fully, and tp do this wc must understand 
their characteristics. 

The simplest is AM. When radioteiephony 
was invented, it utilized amplitude moduL> 
tion. This mode was erroneously believed to 
consist of the varying of transmitted carrier 
power in step with the audio* Some persons 
still believe that this is true. 

To understand AM, one must simply 
understand mixers. When two signals are 
added together in a mixer, the two original 
signals appear in the output, as vi^ell as the 
sum and difference of the inputs. Thus, If a 
] MHz signal is mixed with a 1 kHz sigrial, 
the output consists of four frequencies: 1 
MHz, 1 kHz, .999 MHz, and 1.001 MHz, 

That is what happens in an AM trans- 
mitter. The carrier signal passes through the 
mixefj as well as the audio signal. The audio 
is not passed to the antenna, being far too 
low in frequency. But the sum and 
difference products do pass, and they are the 
sidebands that are transmitted. All intelli- 
gence is transmitted on the sidebands^ and 

the carrier never varies. 

In the receiver, the same process is 

applied to the composite signal. The side- 
bands mix with the carrier, producing 
audible difference frequencies. It is obvious 
that the carrier seryes op necessary function, 



so it can be eliminated in transmission. The 
two sidebands are also identical, so one of 
them can be eliminated, resulting in great 
bandwidth reduction, The bandwidth of AM 
is equal to twice the highest modulating 
frequency. For voice, we assume 6 kHz; the 
bandwidth of single sideband without carrier 
is equal to the highest modulating frequency 
minus the lowest modulating frequency, in 
this case 2.7 kHz. This permits more stations 
to occupy the same band* 

The carrier signal is regenerated in the 
receiver when suppressed carrier is used. If 
one transmits carrier, It will show up as an 
audible note on any AM signal it is near. 
This heterodyning caused tremendous inter- 
ference when AM was the dominant mode of 
transmission, and plagues today's CBers. It is 
especially disturbing when one realises thai a 
majority of the transmitter's output power is 
being wasted on carrier. The carrier, in AM, 
must be greater in amplitude than the sum 
of the sidebands when 100% modulation is 
used. Besides causing QRM, the carrier serves 
to help the transmitter heat the shack and 
generate business for replacement tubes and 
power supplies. A "200 Watt" SSB trans- 
mitter is far lighter than a "200 Watt" AM 
transmitter, because of the easier duty cycle. 



Frequency Modulation? 

More recently, hams have taken to a 
mode called ''frequency modulation." While 
AM does not actually consist of a varying 
carrier amplitude, FM is frequently believed 
to consist of a varying carrier frequency. 
Once again, many hams have made the same 



mistake, Modulatioji consists of the genera- 
tion of sidebands, not the manipulation of a 
carrier wave. 

How wide is FM? The bandwidth of 
double-sideband AM is equal to twice the 
maximum modulating frequency. But the 
bandwidth of FM — ulf useful FM — is 
greater than the bandwidth of the equivalent 
AM signal. This is because FM transmission 
consists of a carrier, whose amplitude varies^ 
and multiple sidebands. The higher audio 
quality of FM, and the superior noise 
limiting, arc due to the redundancy inherent 
inFM, 

Let's examine an FM signal and see what 
makes it tick. First a couple of terms: 
Modulation index is the deviation of the 
carrier divided by the audio frequency 
causing this deviation. Deviation ratio is the 
highest deviation divided by the highest 
modulating frequency. The deviation ratio 
indicates the maximum deviation actually 
found. 

Deviation? That's a bit tougher to 
explain. Deviation is the apparent variation 
in carrier frequency, extrapolated from the 
effect of lowering the modulating frequency 
towards zero. By itself, it's a far less useful 
term than we like to think. The carrier 
frequency of an FM signal does not vary! 
The average frequency is varied by 
modulation, just as the average amplitude of 
an AM signal is varied by modulation, by 
adding sidebands. 

In AM, the two sidebands are in phase. 
Since they rise and fall together, the 
apparent frequency of the envelope does not 



no 



vary. In FM, the sidebands are out of phase. 
Either the upper or lower sidebands are 
more powerful at any given portion of the 
modulating waveform. Therefore, the 
average power in the signal varies in fre- 
quency. 

This phase relationship has' some 
interestihg effects. Since the overall ampli- 
tude does not change, it h possible to 
generate as many sidebands as one might 
want That means greater redundancy, and 
redundancy in any system makes for greater 
fidelity and accuracy. The carrier pov^er is 
distributed among the various sidebands^ and 
reaches zero at several values of modulation 
index. One can measure the deviation of a 
wideband signal by determining how many 
times the carrier dips to zero as the modula- 
tion is Increased. 

To determine the relative phase and 
strength of each sideband, one looks at a 
mathematical concept called a Bcssel 
Fynctibh. Looking at the Bessel chart, one 
can tell which sideband is doing what, when. 
Each significant sideband begins to come up 
rapidly at a given index. One could use the 
chart to determine the bandwidth of an FM 
signal, if the modulation index and fre- 
quencies are known. An easier way is to 
approximate: Bandwidth equals twice the 
deviation plus twice the maximum modu- 
lating frequency. Don't forget that last hajf 
IfketheFCCdidl 

The phase relationship between sidebands 
is complex, but one feature is fairly easy to 
understand. The phase of the odd-numbered 
sidebands is different between the upper and 
lower sides of the carrier, while even- 
numbered sidebands are in phase with each 
other, AM signals have only one set of 
sidebands, the first (odd-numbered), and 
they are in phase. That is a crucial 
difference^ which becomes important in 
phase modulation. 

Phase modulation is similar to frequency 
modulation, but there is one major func- 
tional difference. The frequency response of 
FM is linear^ with equal amplitude tones 
producing equal deviation. PM has a rising 
audio response! with higher frequencies 
generating more deviation, at a rate of 6 
dB/octave. PM deviation is directly propor- 
tional to modulating frequency. 

Phase modulation can be used as FM if 
the audio response is corrected. Communica- 
tions FiVI, such as hams use, is actual iy PM in 
most cases, with an audio response that rises 
within the speech range. This is called 
pre-emphasis. Most FM systems use some 
pre-emphasls. With broadcasting, it is set to 
begin a! about 400 Hz, and rises to about 17 
dB at 15000 Hz, the high end. Even tape 
recorders and phonograph disks use pre- 
emphasis, because noise is linear with regards 
to frequency, and thus most of it is in the 
treble range. Receivers incorporate de- 
emphasis which restores the tonal balance 
while reducing the noise. 

Pre-emphasis is needed with FM for 
another reason. Since the quality of recep- 



tA)POSITIVE PEAK 



(BJNEGATJVE PEAK 



tOENvEUOPE: 



iao% — 



50% — 



LSB 



USB 



Lsa 



USf 




Fig, I, AM sidebands vs. effective envelope. Direction of sideband indicates phase. 



tion is dependent upon the modulation 
index, and the modulation index falls as the 
modulating frequency rises, pre-emphasis 
helps keep the treble range index high 
enough to overcome noise and interference. 

One great benefit of FM's redundancy is 
the capture effect. A signal will completely 
cover a weaker one on the same frequency 
once the capture ratio is attained. This 
works with noise too; a "full quieting" FM 
signal can be just 3 dB stronger than a 
totally unreadable one with a good detector 
and a deviation ratio of about 5^ which is the 
broadcast standard. But if the deviation is 
reduced, the capture effect lessens. Narrow- 
band FM such as is used on 2 meter 
repeaters has very little capture effect, with 
its deviation ratio of 1.6 or less (5 kHz 
deviation and 3 kHz modulation). 

But phase modulation reveals how similar 
narrowband FM and AM really are. One can 
generate PM by actually shifting the phase of 

a carrier. One radian of shift equals a 
modulation index of 1^ but in practice only 
about half that can be achieved with a phase 
modulator, and undisiorted broadcast 
quality must have less shift. !f we accept 
that a phase modulator only produces 
enough shift for one set of significant 
sidebands, we can use the Armstrong 
method of modulationj developed by the 
inventor of FM, Major Edwin Armstrong. 

Armstrong knew that PM and AM 
differed mainly in phase relationship, so he 
generated a double sideband signal in a 
balanced modulator, shifted it ninety 



degrees, and reinstated the carrier. The 
result, provided the carrier was strong 
enough^ was PM, This system has been used 
in broadcast transmitters, but the amount of 
frequency {and hence, deviation) multiplica- 
tion needed is very great. For wideband use, 
direct FM is easier. Note that there ts no 
pretense of shifting the carrier frequency 
with the Armstrong method. What slight 
amplitude modulation results is quickly lost 
in the Class C multipliers needed. Try 
feeding AM into Class C multipliers, but not 
with an antenna! 

FM Reception 

The simplest way to receive AM is with a 
diode demodulator. The best way is with a 
synchronous detector, which takes advan- 
tage of the redundancy of the two side- 
bands, but that practice is not yet common. 
Diode detectors don't work with FM, since 
the sidebands all cancel each other's 
amplitude variations and beat frequencies. 
Thus, to detect FM, a different system was 
invented. The most common is the discrim- 
inator. 

The discriminator compares the amount 
of signal above the center frequency with 
the amount below the center frequency. The 
resultant voltage reflects the modulation. 
Whether there are sidebands or a swinging 
Carrier does not matter here, The ratio 
detector is a variant of the discriminator that 
automatically cancels amplitude variations, 
such as AM and noise. Both forms are 
common. 



(AJNARROWBAND 



C8)W1DER BANDWIDTH 



Fig. 2. Narrowband vs. wideband FM, 



DEVIATION 



4K ,- 



3K - 



aK - 



K - A 



1 




J L 



J 



IK 2K 3K 4K 

MODULATING 
FREQUENCY 

F/g. 3. Modulation frequency vs, deviation, 
(a) Phase moduiatJon, (b) Direct FM. (c) 
Compromise pre-emphasis. 




ETC. 



Fig, 4, Bessel function showing amplitude 
and phase of various sidebands. 



111 



One newer way is to use a phase locked 
loop. The PLL is a necessary part of an AM 
synchronous detector, where its advantages 
are drastic over the older diode system. With 
FM, the PLL dececior attempts to lock an 
oscillator onto the frequency of the input, 
which appears to vary as the average of the 
sidebands swings back and forth (it acts 
almost as if there really were a swinging 
carrier). The important advantage is that a 
PLL need not receive the entire FM signal, 
but only the first two sidebands on each 
side. It will then have enough to lock onto. 
By receiving a wideband signal as if it were 
narrowband, the receiver can slice out noise 
and interference among the ouler sidebands^ 
at the expense of widebarKl's quieting. A 
PLL detector also inherently tracks drift 
with less distortion than a discrtminator, 
without an automatic frequency controE 
circuit. 



So What's CW? 

We have already seen that the carrier does 
noi vMy in amplitude when we transmit AM, 
and that the carrier docs not vary in fre- 
quency when we use FM, Let's apply our 
understanding of AM type A3 telephony to 
type Al telegraphy — good old CW, 

CW is a form of AM, and thus has a 
bandwidth and sidebands. The sidebands are 
generated by the keying, since a change in 
effective amplitude necessarily causes side- 



bands. The bandwidth of a CW transn^itter is 
determined by the key click filter. U the 
transmitter's rtsc tfmc is short (sharp 
keying)> there may be clicks, which are 
wider sidebands than necessary. If the rise 
time Is made very long, the dils will get 
mushed with fast code. Contrary to common 
belief, keying speed does not affect band- 
width. Potential keying speed does, and a 
Novice probably shouldn't use as little 
keying filtration as a fast brass-pounder* 

Now for the clincher: Since CW is a form 
of AM ( modulated by squared waves, so to 
speak), it follows that keying (modulation) 
should not affect the carrier. Here's a logical 
sequence, all of which is true in its own way: 

1, In conventional full-carrier AM, the 
amplitude of the carrier is not affected by 
modulation. Sidebands are generated which 
carry the information; the composite 
amplitude of the carrier plus sidebands varies 
by the addition and subtraction of carrier 
and sidebands. 

2L Assume series-^te AM transmission 
(grid modulation). When the modulaiing 
waveform is ai its most negative, the 
modulated grid reaches the point of zero 
tube output. At its most positive, the lube 
reaches maximum output. This system 
produces a carrier and sidebands as per 
above, 

3. Assume a square wave is fed into ihe 
modulated stage. During one half the cycle, 
the tube is entirely cut off; during the uUier 



half, the tube conducts completely. The 
ironclad rule of AM — carrier unmodulated 
by sidebands - still stands; the high 
harmonic content of the square wave 
produces broad sidebands. Softening the 
waveform by the addition of a tow-pass filter 
to the modulation reduces the width of the 
sidebands. 

4, Replace this square wave with a tele* 
graph signal. There are still sidebands and an 
unaffected carrier, even though the tube is 
cut off during part of Ihe waveform. This is 
common grid-block keying CW, Even with 
the key up, the carrier is stilt there * 

Now you know as well as I do that wfren 
a key is lifted, the carrier goes away, right? 
But pui in a narrow CW filter, say 40 H/, 
and key rapidly, tt will be noticed that the 
keying is softened if not obliterated by the 
"ring" in the filter. This ring can be reduced 
by proper filter design, but a certain amount 
is inherent in any given bandwEdlh, because 
the higher order sidebands are being cut off 
by the filters! If one were, theoretically, to 
narrow the bandwidth to a fraction of a H/, 
the signal would ring for several seconds. 
Narrow the filter infinitely, and the carrier 
remains infinitely present. The sidebands are 
close to, and out of phase with, the carrier. 
In case youVe thoroughly confused, just 
remember that a carrier wave is really only a 
mathematical concept, and like mosi mathe- 
matical concepts, carries very little 
intelligence to most of osl ■ 



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LJS2:m:.fe' 



ry Ts-520 

(Specifications 



JW0DE5: USB, LSB, CW 

POWER. 2 00 walls PEP mput on SSS, 160 watts 

DC input on CW 
ANTENNA tMPEDANCE: 50-75 Ohms. 

unbalanced 
CARRIER SUPPRESSION: Better th3ri-45 dB 
UNWANTED SIDEBAND SUPPRESSION: Better 

than -40 dB 
HARMONIC RADIATION: Better than -40 dB 
AF RESPONSE: 400 to 2600 H? (-6 dB) 
AUDiO INPUT SENSITIVITY; 0,25juVtor 10 dB 

(S-NVN 
SELECTIVMV- SSB 2.A kHz (-6 dB). 4.4 kHz 

[-60dB}CW 0-&kHzf-6dB). 1.5kH? 

(-60 dB) (witfi accessory filleO 
FREQUENCY STABILITY: 100 Hz per 30 

minutes afier warmup 
IMAGE RATED: B&tter than 50 dB 
If REJECTION Better iJian 50 dB 
TUBE & SEMiCONDUCTOR COMPLEX ENTj 

3 tubes (2.? 514€B. 12BY7A), 1 FC, IB 

FET. 4-4 transistors, S4 diodes 

DIMENSIONS: 13.T'^ W x 5.9" H x la.Z'"- D 
WEJGHT: 35.2 lbs. 
SUGGESTED PR[CE: $£29. 00 



VFO-520 



Provides high stability witb precis ton gearing. 
Function switch provides any combination with 
the TS-520. Both are equipped with VFO indi- 
cator$ showing at a glance which VFO is being 
used. Connects with a single cable and obtains 
it$ povv^f iTorn the TS-52d. Suggested price: 
$115.00. 



SP-520 



Although ^he TS-520 has a built-in speaker, the 
addition of the SP-520 provides improv&d tonal 
quality. A perfect match in both design and 
performance. Suggested prate: $22.95. 



SJSK^tf^SS;.? 



**r 



^*m-^- 



^ "^ 



s^ 



Kenwood's TS-520 has sold itseli to 
thousands of amateurs the world 
over. 

The value of its features and specifi- 
cations are obvious. But }usl as impor- 
tant is the kind of quality that Kenwood 
builds in- Hundreds of testimonials on 
the air attest to its performance and 
dependabilitY- You probably have 
heard of some ol the same glowing 
praise. 

The TS-520 operates SSB and CW on 
80 through 10 meters and features 
built-in AC and 12VDC power supply- 



VOX, RIT, noise blanker, 2- position 
ALC. and double split Irequency con- 
trolled operation are only some ol its 
fine features. 

Kenwood offers accessories guaran- 
teed to add to the pleasure of owning 
the TS-520. The TV-502 transverter 
puts you on 2-nieters the easy way. 
(It's completely compatible with the 
TS-520-) Simply plug it in and you're 
on the air. Two more units designed 
to match the TS-520 are the VFO-520 
external VFO and the model SP-520 
external speaker. All with Kenwood 
quality built in* 



TV-502 



TRIO-KENWOOD COIVIMUNICATIONS IWC. 116 EAST ALONDRA/GARDENA. CA 90248 



TRANSMITTING/RECESVlNt^ FREQUENCY: 

144-145.7 MHz 145.0-146.0 MHz (optton). 
INPUT/OUTPUT IF FREQUENCY: 28.0-29.7 

MHz 
TYPE OF EMISSION: SSB (A3J), CW fAi) 
RATED OUTPUT: 8W (AC operation) 
ANTENNA INPUT/OUTPUT IMPEDANCE: 50^.. 
UNWANTED RADIATION: Less than -60 dB 
RECEIVING SENStTIVITY: ^ore than l/iVat 

S/N 10 dB 
IMAGE RATIO: More thars SO dB 
IF REJECTION: More tt^an 60 dB 
FREQUENCY STABlLlTV" Less than ^.2.5 kHz 

during 1-60 min after power twitch is ON 

and w-ithin 150 Hz fper 30 min) thereafter. 
POWER CONSUMPTION: AC 2 20/1 20V, Trans- 

rnission SOWrnaK., Reception 12Wmax. 

DO 13.BV. TFans- 

mission 2A max.. Reception 0,4A mas 
POWER REQUIREMENT: AC 220/120V, DC.12- 

16V (standard vottaEe 13.SV) 
SEMt -CONDUCTOR; FET 5, Transistor 15, 

Diode 10 
DIMENSIONS: 6%" Wx 6" H x 13Va"D 
WEIGHT: 11.5 lbs. 
SUGGESTED PRICE: 1249.00 

0^520 

500 Hz CW Crystal Filter $45 OO. 

Prices subject to change without notice 



Louis Berman K6BW 

Department of Physics 
University of San Francisco 
San Francisco CA 941 J 7 



Is Extraterrestrial 
Communication Possible? 



Throughout human his- 
tory the art of long- 
distance communication by 
audible^ visual, or electromag- 
netic methods has played an 
important role in advancing 
the culture of the human 
race. When Homo ercctus 
emerged from the mists of 
antiquity a couple of million 
years ago, his upright position 
freed his hands for the deli- 
cate manipulation of tools 
and led to the development 
of a larynx and speech box 
that set him apart from all 
other animals. One can 
imagine early man communi- 



co m m u n i cation succeeded 
with the advent of tele- 
graphy. In that same century 
a few a d V $ n t u r^ s o m e 
dreamers had already set their 
sights much farther out- 
Among the elabdrate schemes 
that had been concocted to 
signal our presence to other 
worlds in the solar system 
were the following: the plant- 
ing of a ten- mile- wide strip of 
pine trees in Siberia in the 
form of a right triangle; a 
twenty-mile circular ditch 
filled with water over which 
kerosene would be poured 
and set afire; a powerful con- 



For all we know, CQs may be coming our way, unbeknown 
to us, by sophisticated communication techniques beyond 
our comprehension, just as the New Guinea natives who 
communicate with drums are unaware of the international 
radio traffic passing over their heads , . . 



eating over distances with his 
brethren by means of strident 
calls, and his successor, Homo 
sapiens^ by means 6T fire or 
smoke signals, drum beatings, 
sunlight flashes from shiny 
objects, and other primitive 
methods. 

ft was not until a century 
ago that man's effort to over- 
come great distances by rapid 



cave mirror that would focus 
sunlight on Mars and burn 
simple numbers in the desert 
sands of that planet; a net- 
work of large sunlight-reflect- 
ing mirrors stategically posi- 
tioned in several European 
cities to conform to the con- 
figuration of the Big Dipper 
in the constellation Ursa 
Major as a sign of intelligence 
on earth. 



In 1899 the eccentric elec- 
trical pioneer, Nikola Tesla, 
undertook to transmit a 
powerful electrical signal into 
space from his Colorado 
laboratory and to detect any 
possible replies. He employed 
a large primary coil 75 feet in 
diameter and a 3 foot copper 
ball mounted on top of a 200 
foot tower. He figured that 
powerful alternating surges of 
electricity introduced into 
the copper ball and into the 
ground would interact with 
the earth's magnetic field to 
increase the power of the 
radiated signal. Although 
there were no extraterrestrial 
responses to his efforts at the 
time, it was reported that 
incandescent tights were set 
glowing 26 miles away. A 
year later he claimed to have 
picked up interplanetary sig- 
nals. 

In 1921 Gugllelmo 
Marconi believed he had 
detected regular pulsed 
signals from outer space in 
the high meter band while 
conducting atmospheric tests 
aboard his experimental 
yacht, the Elettra. In 1924, 

when Mars was closest to the 
earth (35 million miles), the 
astronomer D a vi d Todd 
arfanged to have the U.S< 



government's high-powered 
transmitters turned off every 
five minutes before the hour 
between August 21 and 
August 23. During these five 
minute silent intervals he 
used a special receiver tuned 
between 50 and 60 kHz to 
record on tape any signals 
coming through. Out of a 
hodgepodge of dots, dashes 
and jumbled code groups, 
which he and listeners 
throughout the country 
heard, nothing definite could 
be ascribed to an outside 
source, Today we know that 
such very low outer-space 
frequencies are reflected back 
into space by the ionosphere- 

Throughout the following 
quarter century interest in 
extraterrestrial communica- 
tion more pr less lapsed until 
the growth of radio astronomy 

after World War II. As radio 
telescopes grew in size and 
observing tech ni ques 
improved, the time seemed 
opportune to speculate once 
more on the feasibility of 
detecting cxtrasolar signals 
from intelligent sources in 
space. In a September 19, 
1959 issue of the prestigious 
British scientific Journal 
Nature^ physicists Giuseppe 
CoCtohi and Philip Morrison 



114 



presented logical reasons for 
instituting a search to detect 
artificial signals in outer space 
with large radio telescopes. 
They concluded that the 
probability of finding any 
was difficult to estimate^ but 
if we never search^ the chance 
of success is zero. 

In 1960 the first modern 
attempt to look for artificial 
signals in space was con- 
ducted by Frank Drake at the 
National Radio Astronomy 
Observatory in Green Bank, 
West Virginia. This was the 
faitious Project Ozma named 
after the legendary princess in 
the imaginary (and of Oz. The 
85 foot radio dish was 
pointed, when time per- 
mitted, in the direction of 
two relatively close solar-type 
stars, Tau Ceti and Epsilon 
Eridani, about eleven light- 
years distant. After 150 hours 
of unrewarded observing 
from May through July, the 
search was abandoned. 

In 1967 there was a brief 
flurry of excitement when 
the first pulsar was dis- 
covered. Perhaps 'little green 
men" were trying to contact 
us with their very precisety- 
timed pulsed radio signals. We 
have since found over one 
hundred pulsars in different 
parts of the sky flashing radio 
pulses up to thirty times per 
second. They are the natural 
consequence of certain stars 
that have gravitationally 
collapsed after exhaustion of 
their available nuclear fuels 
into small, raprdly'Spinning, 
h i g h 1 y c o n de n s ed o b jec ts 
emitting beamed radio pulses 
which the earth intercepts. 

In the ensuing years there 
have been a few sporadic 
attempts undertaken to 
detect artificial signals in 
outer space, particularly since 
1972, So far several American 
and Canadian radio astrono- 
mers have been unable to 
locate anything resembling 
intelligent coded signals from 
a number of nearby sunlike 
stars. Neither have attempts 
by two groups of Soviet 
astronomers, seeking pulsed 



intelligent signals over the 
entire sky from any source, 
been successful to date. The 
most unusual search in 
progress is that conducted 
with the Arecibo 1000 foot 
radio telescope in Puerto 
Rico. Here several nearby 
galaxies with their billions of 
stars are being monitored 
intermittently on several 
microwave 'channels. There 
are presently too many other 
immediate and rewarding uses 
of radio telescopes than to 
spend lime looking for coded 
extrasolar signals with little 
hope for success. 

It would seem that 1420 
MH^; is a logical search fre- 
quency of universal signifi- 
cance. It is the emission fre- 
quency of the dark, neutral 
hydrogen clouds that outline 
the spiral arms of our galaxy. 
This fr^qLJehcy happens to lie 
in the quietest terrestrial por- 
tion of the microwave spec- 
trum between 3 and 30 centi- 
meters where the effects of 
atmospheric absorption and 
cosmic background noise are 
at a minimum. If other 
galactic inhabitants are also 
surveying the hydrogen distri- 
bution in the galaxy, their 
receivers and ours, tuned to 
the same spectral region^ 
might offer the best chance 
of the successful receipt of 
coded transmissions around 
the hydrogen-emitting fre- 
quency. However, it is con- 
ceivable that an advanced 
galactic society, desiring to 
leave this channel open for 
exploration of the galactic 
structure iust as we do, will 
not beam CQs on or near this 
frequency. A more suitable 
CO m m u n i c ation frequency 
might be the microwave 
region between the emission 
lines of hydrogen (H) at 1420 
MHz and hydroxy I (OH) at 
1668 MHz observed in the 
interstellar clouds of our 
galaxy. This microwave 
section has been called the 
water hole because H and OH 
are the dissociation products 
of water (H2O). If water- 
based life is prevalent else- 



where, it might be natiural for 
advanced societies to employ 
a precise frequency related to 
the center of mass of the 
water molecule. This com- 
munication frequency lies at 
1652.42 MHz. 

We must remind ourselves 
that we are tyros in the com- 
munication enterprise. For 
us, passive listening is 
presently far more advan- 



bi nary 'Coded, beamed signaf 
in the direction of the great 
globular star cluster in 
Hercules. Even though its dis- 
tance is 24,000 light-years, 
this object was chosen 
because the beam width of 
the arriving signal 24,000 
years from now would just 
span the diameter of the 
cluster, thus wasting no 
power; secondly, there might 



Project Cyclops involves an array of some one thousand 
100 meter dishes spread out over a circular area ten miles 
wide at a cost of TO billion dollars, about one-third the cost 
of the manned missions from Mercury to Sky lab. The 
installation would be capable of intercepting coded beacon 
signals from civilizations out to 1,000 light-years , . , 



tageous than active beaming 
whji^h requires enormous 
expenditures of energy. 
Obviously, if there are no 
civilizations with the will to 
transmit as well as to receive 
out of the hundreds of thou- 
sands that presumably exist 
in our galaxy of several 
hundred billion stars^ inter- 
stellar communication will 
never materialize. For all we 
know, CQs may be coming 
our way unbeknown to us by 
sophisticated communication 
techniques beyond our com- 
prehension, just as the New 
Guinea natives who commun- 
icate with drums are unaware 
of the international radio 
traffic passing over their 
heads. The acquisition of a 
message obviously is the most 
difficult part in establishing 
an interstellar dialogue. Once 
acknowledged and replied to, 
assuming we can decipher it, 
arrangements can be made 
with respect to channels of 
operation, power requtre- 
mentSj and communication 
rnodes for the proper 
exchange of knowledge 
between two galactic cultures, 
even if this takes centuries. 

Our first active attempt to 
beam a message to a distant 
stellar outpost was made in 
November, 1974. The newly- 
resurfaced 1000 foot radio 
dish at Arecibo, Puerto Rico 
focused a 450 kilowatt, 



be a sufficient number of 
civilizations out of the 
million stars in the cluster 
capable of intercepting the 
'*astrogram." The binary- 
coded message contained 
information about the earth's 
biology pertaining to the 
composition and structure of 
the DNA molecule, the 
human population, an inven- 
tory of the solar system, and 
a schematic of the radio tele- 
scope that beamed the coded 
signal. 

Lastly, there remains for 
discussion the most grandiose 
project of all: the Cyclops 
system of communication 
proposed by Dr- B. Oliver, a 
vice president of the 
Hewlett-Packard Company, 
Project Cyclops involves an 
array of some one thousand 
100 meter dishes spread out 
over a circular area ten miles 
wide at a cost of 10 billion 
dollars, about one- third the 
cost of the manned missions 
from Mercury to Sky lab. The 
installation would be capable 
of intercepting coded beacon 
signals from civilizations out 
to 1,000 light-years, or eaves- 
dropping on the radio leakage 
from local transmissions 
broadcast by communicating 
societies up to distances of 
100 light-years. The array 
could also be used to radiate 
directional signals with 
extremely narrow beam 



1t5 



lobes, A large fraction of its 
lime would, in addilion^ be 
devoted to investigations of 
natural radio sources on the 
sky. It is estimated thai 
within 1,000 light-years there 
are some 1.7 million suitable 
stars. By "suitable" we mean 
solar- type stars which possess 
sufficiently long life spans to 
permit ihe slow, orderly 
biological planetary evolution 
of an intelligent species, For 
example, our sun is about 4*5 
billion years old and biologi- 



cal evolution on earth 
required about 33 billion 
years to produce modern 
man. Under the optimum 
conditions wherein inter- 
Stellar beacons operate con- 
tinuously and we can monitor 
all likely channels simultan- 
eously in the microwave 
region with a receiver having 
at least one billion outputs^ 
the search could be conv 
pleted in about 30 years. 
Otherwise we should be pre- 
pared to spend centuries of 



effort in a project with some 
chance of success in the 
distant future. 

In the meantime^ there 
remains the slim prospect of 
serendipitous contact. We 
might accidentally stumble 
onto artificial signals being 
randomly directed our way^ 
intercept signals being 
exchanged between two other 
worlds, locate signals between 
a cruising spaceship and its 
parent planet, detect signals 
from an automated probe 



monitoring our solar system 
and reporting to its home 
station or mimicking our 
communication to gain recog- 
nition (an unlikely source of 
long-delayed echoes), or 
eavesdrop on a galactic net- 
work exchanging information 
among its member soctetfes* 
Once interstellar communica- 
tion is initiated, it will mark 
the end of our cultural isola- 
tion and establish our entry 
into the galactic club of 
civilized societies. ■ 



Autobiography 



vj 



T 



Ancient Aviator 



wM 



it! 






W. Sanger Green 
1379 E 15 Street 
Brooklyn NY 11230 



MORE DEPARTIVIENT OF COMMERCE STUFF 



Last month I told vou atx>yt my 
official headquarters being changed 
from Washington to Philadelphia. It 
was much berier than uavehng out of 
Washington for 30 to 40 days wiihout 
swing my family. So, as ! told you, 
the first thing I did after receiving the 
assignment was to move my wife and 
Wayne to Phifadelphia. 

In those days there were only three 
classes of pilot licenses: Iran sports 
Limited Commercial and Private, each 
with its limitations. Alf required a 
written examination and a fliqht Test. 
It was up to the appEicant to furnish 
the airplane for his flight test. If the 
flight test was in a dual control ship, 
I'd ride with him to see how much he 
slipped and skidded on \\\t turns, 
figure 8s, 180s and 3605 - In other 
worck, to see whether he was Nying 
tlte ship or the ship was flymg him. 
Also. I very seldom licensed an air- 
plane without lest flying it myseff. I 
had three inspectors assigned to my 
r^ii>n, so the first thing I did was 
make up a schedule of dates and 
places where one of us would be 
available to inspect aircraft arid to 
examine and test for pilot and 
mectianit licenses. This was sent to all 
itie active airports tn the region and to 
all applicants. 

On one of my trips to the f^ictv 
mond Flying Field \ had an appMca* 
t ion for a license foi- Roscoe Turner's 
"Frying Cigar Store*' ship. If I remem- 
ber cofrectly, it was a large sirvgle 
engine biplane th^t. \ believe, was an 
early Igor Sikorsky stick and wire \ah. 
it was verv well buifi and, according 



to Roscoe, was very nice to fty. It had 
to be good since the runway he 
operated out of, across the fie Ed from 
the Pitcxairn hangar, was only about 30 
feet wide and had deep ditches on 
each side, At that time Roscoe had a 
pet crow that he look everywhere 
with him. The crow had a habit of 
picking up anything that was shiny 
such as a wrer^ch, pliers, etc., and 
hiding it. What fun. As you may 
possibly remember, Rosooe was 
always dressed in smart uniforms. I 
asked him where he got them and he 
said that his wife designed and had 
them made for him. Anyway, uniform 
or not, Roscoe was an excellent pilot. 
In late 1927 and early 1928 I spent 
qutte a little time based at Lang ley 
Field, Virginia. I was stationed there 
in 1925. 90 1 still had a tot of friends 
there. They put me up in the B.O.Q, 
(Bachelor Officers' Quarters) m^d, for 
a very nominal fee, fed me at tfieir 
mess. The NACA (National Advisory 
Committee for Aeronautics) very 
kindly t^ngared my plane. Qyite a 
few of the pilot personnel at 1-Bngley 
and at the Naval Air Base at Norfolk 
wanted to qua Iff v fof civitian pilot 
licenses, so I processed their applica- 
tkins. Also, some of the "l^n Corns" 
and Specialists Qualified for airplane 
or engine mechanics licenses. The 
NACA had quite a stable of planes in 
their fiartgar, some of which they were 
nice enough ro let me fiy. Font my 
mor>eyp their Fokker D7 was ttie best 
tiandling ship of the lot, Tom CarroL 
an old friend of mine, was chief test 
pilot for the NACA at tf^t lime. 



On the morning of the 15th of 
November 1928, I answered the 
phone at my office at the Philadelphia 
Airport and heard someone say, 'This 
Is the White House Vacuum Cleaner 
Department*' {Hoover was then the 
Secretary of Commerce}. I knew right 
away that it was Ralph Lock wood, 
the Supervising Inspector in Washing- 
ton and my boss. I asked him why he 
was wasting the ta>tpayer's money on 
long distance phone calls. He said they 
had a problem and needed my help. 
He saidv "You know that nice new 
Stearman we have in our Boiling Field 
hangar?'' I said, ''Yes." "WeJI," he 
said, "Clarence Young (Chief Air 
Regulation Division, and Lockwood's 
boss) is going to make a tour of 
Europe next month and wants to take 
the Stearman along. However, in order 
to do this, the ship needs some addi- 
tional instruments and a radio installa- 
tion thai can only be done at the 
Stearman factory in Wichita, So 
Clarence wants you to ferry il out and 
back/' I told him that it would be son 
of difficult (or me to get away just 
then as we had just raised the price of 
an untested pilot license to SI 00 and 
the price of covering up a dry rotted 
longeron to SI 50, and we were busy 
running to the bank. He ar^swer was 
for me to throw a couple of shirts m 
my flight bag and (ly down to Wash- 
ington that afternoon. They would 
have the Stearmsn on the line, all 
gassed, wanned up artd ready to go 
first thing in the morning. Well, an 
order is an order — so I complied. 

Instrumental ton in most civil air- 
craft in those d&ys was pretty sketchy. 
hAany were equipped with only a 



compass, altimeter and air speed indi- 
catof, some with a turn stkI bank 
indicator. This was about the story for 
flying and r^vi gating instruments. The 
Stearman had all tfiese for the out- 
bound trip plus a rate of climb indi^ 
cator and radio on the return trip. An 
ItOO to 1200 mile cross-country trip, 
especially if it was not over 
established airways, was a bit more 
complicated in 1928 than it is now. 
To be stire, there were airway strip 
maps to be had, but once you were 
off those, the Rand McNally state 
maps were about the only maps avail- 
able. So you drew your flight line on 
the state maps and tried to follow it 
Following railroads in mountairious 
country was not recommended as 
they sometimes went into tunnels 
without warning, A combination of 
visual and compass navigation was 
what I generally used. 

The trip out was normal for late 
November — high head winds, snow, 
sleet, etc. I had to make an un- 
scheduled landing and overnight at 
Terre Haute because the ground was 
getting a little too cEose. There were a 
lot of heavily flooded areas between 
Angium and Kansas City, and snow 
from there to Wichita. Upon my 
arrival, I phoned Stearman and told 
him 1 had arrived with the package he 
had been expecting from Clarence 
Young. He said he'd send a pilot to 
lake the ship over to his postage 
stamp sized factory fanding place. It 
took them four days to do the work 
on the ship. Then, while I was tastir^ 
it, prior to returning to Washington, 
the lever controlling the horizontal 
stabifi^r Eet go and put me into a dive 
I coialdn^t control with the elevators. I 
lost about dOO or 900 feet before I 
realized what had happened and t 
corrected it jtist in tin^e. Ail 1 had to 
do W3S to pull the stabilizer control 
lever up and hold rt with my left hand 
while I operated the cor^fol slick and 
tf^rotlJe with my knees and right hand 
to tsme in for a larxling. ft didn't take 
Stearman more than a couple of hours 
to make the necessary repairs, so I was 
on my way by noon. 

I got back to Washington the after- 
noon of November 24th jusi in lime 
to jump into my Travelair and make 
Philadelphia before dark. • 



116 



fflC-8 SIGHT TOnC CflCODCR 



Compatible with all sub-audible tone systems such as: 
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• Powered by 6-1 6vdc, unregulated 

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• Available in ail ElA tone frequencies, 67.0 Hz-203.5 Hz 

• Complete immunity to RF 

• Reverse polarity protection built-in 

• All connections to board made with push-on 
connectors, color coded wires supplied 

• Instant start-up 

• Frequency selection made by either a pull 
to ground or supply on control lead 

• Full 1 year warranty 

• Mounting hardware supplied 






i-KhUUENCIES AVAILABLE 




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77.0 


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131.8 


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79.7 


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136.5 


4Z 


82.5 


YZ 


141.3 


4A 


85.4 


YA 


146.2 


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88.5 


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151>4 


5Z 


91.5 


77 


156,7 


5A 


94.8 


ZA 


162,2 


58 


97.4 


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167.9 


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100.0 


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173.8 


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103.5 


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179.9 


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114,8 


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W. G. Moneysmhh VJBKUT 
2}740Miiiiary 
DBarborn Ml 48124 



5/8 Wave Power for Your HT 



The maiority of the com- 
mercially made two 
meter FM hand- held trans* 
ceivers today have I or 2 
Watts output into quarter 
wave antennas or rubber 
ducks. There are many times 
when an FM operator would 
like to have a (ittle more gain 
to work out better from poor 
locations. This article 
describes a tunable 5/8 wave 
telescopic antenna to use 
with a rig such as the Drake 
TR-22 transceiver. 

The antenna design is not 
a new one. However, the 
adaptation lor use with 
portable equipment and base 
stations is novel. It basically 
consists of four parts: (1) a 
44" or 45'* telescopic tran- 
sistor radio replacement 
antenna rod; (2) acrylic 1/2" 
OD, 1/4" ID, 2-1/2" long 
plastic insulator; (3) a 4 turn 
coil and an NPO 3-12 pF 
ceramic trimmer; (4) PL-259 
coaxial connector. Use with 
the TR-22 transceiver 
requires an additional 90** 
elbow, a barrel connector and 
a double male connector. 

Construction of the 
antenna is a little unusual, 
but can be done easily in 
about an hour. First, with the 
2-1/2" acrylic rod, drill a 
5/16" hole, M/2" into the 



center of the rod tube. The 
metal telescopic rod will fit 
into this later. Next^ prepare 
a 1" by 1/4** wooden dowel 
rod. Drill a small hole 
through the end of the dowel 



to pass a center conductor 

wire. Glue the wooden dowel 
into the bottom of the plastic 
insulator tube and drill a 
small angular hole through 
the side of the plastic rod to 




k 



^ 44 in. TELESCOPIC ANTEMNA ROD 



S/lgin. 



1 




l/ISin, HOLE DRILLED THRU ROD 

DRILL OUT 

1/2 in D I ^. PLASTIC ROD, 1/4 In. HOLE THRU 

NO. 3-48 SCREW, NUTj STAR WASHER 



SMALL MOLE DRILLED TO PASS CENTER 

tONOUCTOR WIRE 

r/4in.DlA.W00D DOWEL; SMALL HOLE THRU 
END, 0LUE INTO PLASTIC 

coil: 4T no. 12 COPPER WIRE; TAP I TURN 
FROM COLD END- J /2 if*, I. D. * 3/4 in LONG 



NPO 3 -12 pF ^ 
CERAMIC d 
Tf^lMMER ^ 



SOLDER TT> 
OUTS10C OF 
PL- 2 59 



CENTER CONDUCTOR FROM RGSB COAX, 
SOLDER TO CENTER CONDUCTOR OF PL-25ft; 
OTHER END RUNS THRU WOOD DOWEL FILL 
PL- 259 WITH EPOXY TO SECURE DOWEL 



PL-25S 



DRAKE 

TR 22 XCVH 




Fig. h 



coincide with center hole of 

the dowel. Solder a 3'* piece 
of center conductor from 
RG-58 coax to a PL-259 
codxiai connector. Fish the 
loose end of wire up through 
the wooden dowel and out 
the side of the plastic insu- 
lator. Next, fill in the Pb259 
connector with epoxy and set 
the wooden dowel into the 
connector. Be sure to pull the 
center conductor wire as you 
work the dowel into the 
epoxy. Let cpoxy set up until 
hardened. Next, wind a coil 
using #12 copper wire (1/2'* 
ID, 4 turns). Bend the ends of 
the coil and leave plenty of 
excess wire to make the 
hookup. Position the coil 
over the plastic insulator and 
slide it down until ihe first 
turn reaches the PL-259. File 
off the chrome plating from a 
spot on PL* 259 and solder 
the bottom end of the coil. 
Solder to the coil the center 
conductor wire coming 
through the side of ihe plastic 
Insulator, at 1 turn from the 
grounded end. 

Insert the 44" telescopic 
antenna rod into the top of 
the insulator. Drill a 1/16*" 
hole through the insulator 
and antenna rod. Secure with 
a ^3-48 screw, nut, star 
washer and lug. Solder the 



118 



top end of the coil to the lug 
and tighten it down. Finally, 
solder an NPO 3-12 pF 
cefamic trimmer between the 
top and bottom of the entire 
coil. Extend the antenna rod 
to full length and check for 
rigidity. This completes the 
construction. 

With a Drake TR-22, an 
additional 90"^ elbow coaxial 
connector, a barrel con- 
nector, and a double male 
connector must be used to 
adapt the antenna to the 



TR-22 coaxial SO-239 output 
connector at the rear of the 
unit. 

Tune-up procedure is very 
simple; there are two ways* 
First, using a field strength 
meter in close proximity, key 
the transmitter and adjust the 
NPO capacitor with an insu- 
lated tuning wand for max- 
imum meter indication. Or, 
while listening to a weak 
signal, adjust the NPO 
capacitor for maximum S- 
meter indication. Bath 



methods are with the antenna 
in place and the rod fully 
extended. 

The antennas constructed 
thus far have been very effec- 
tive, with increased receive 
and transmit gain over the 
built-in quarter wave lype 
antennas. Many repeaters in 
excess of 35 miles have been 
worked using this antenna 
and a 1 Watt rig. It is very 
useful in the home and shop, 
and at picnic outings and 
other portable locations. It is 



a fun little antenna to build 
and can be used not only for 
hand-hefds but also for 
Regency HR'2 type rigs, loo. 
Those who have the problem 
of no antenna allowed 
outside can use this antenna 
and have many surprising 
results, especially from the 
second floor of a structure. In 
most cases it will mount on 
the SO-239 at the rear of the 
rig. Be sure to re-tweak the 
NPO capacitor when changing 
rigs for optimum perfor- 
mance! ■ 



If you are on 2-meters now 

. . . but you're tired of being stuck 
with too few channels 

. . . and you'd like more versatility 

. . . and you really do need tunable 
VFO 

. . . and SSB-CW (don't forget 
OSCAR!) 

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Having just recently read 
an article by WB4DCV 
in the Nov/Dec 1975 issue of 
73 Magazine, and another by 
WB2DFA in the Jan 1976 
issue of Ham Radio ^ I 
thought it might be timely to 
write up some of the Ideas 
used around here for strobing 
and general control of 
displays. If I didn't strobe or 
llmeshare some of them, I 
could not afford my light bill 
each month. 

While this is not a con* 

Siruciion article, it might help 
some of your present or 
future projects. Since nearly 
all digital projects do their 
**thinking" in a binary or 
BCD code, a transition 
usually occurs somewhere in 
an tC (or ICs) that converts 
this code to the required 
seven-segment code and the 
readout numbers we under- 
stand. Further, this generally 
occurs in a 7446, 7447, 7448, 
etc., family IC or CMOS 



Fig. L 

equivalent. These little multi* 
pin "black boxes'* more often 
than not have a group of 
gates that seem to get over- 
looked quite often. Blanking, 
strobing, etc, are the very 
reasons these gates were built 
into the IC, so it is a shame to 
overlook them at the expense 
to our pocketbooks! 

There are two pins on 
most of these ICs, referred to 

as the ripple blanking output 
(RBO) and the blanking or 
ripple blanking input (RBI) 
lines. Hooked together 
properly, these pins can be 
used to blank out what are 
called the leading zero figures 
on a display, or the 2ero(s} 
preceding the actual number 
desired (i.e., the OOV23 in the 
number 123), Another 
example: In a 5 digit counici 
like the K20AW counter that 
I wrote up some additions for 
earlier (73 Magazine^ )une, 
1973), a very worthwhile 
further addition can be 



realized by using these 
RBO/RBI lines wired 
properly for the leading edge 
zero blanking. By tying pin 5 
of the most significant digit 
(left figure as viewed by user) 
IC SN7446 to ground, then 
tying pin 4 of the same IC to 
the next lesser significant 
figure IC SN7446 pin 5, and 
carrying pin 4 of one IC to 
pin 5 of the next IC to the 
ri^t, on down until only the 
right-hand pair of digits (their 
7446s) are not modified^ you 
will blank all zero figures to 
the left of the right-hand pair. 
Examples: 00001 will read 
01, 00011 will read 11, 
00111 will read 111, 01111 
will read 1111. and 11111 
will read 11111. If 10001 is 
the number, then 10001 wilf 
read out. Only insignificant 
zero figures are deleted and 
blanked. Leave at least two 
right-hand digits unaffected 
in order to tell that the 
counter is indeed running and 
working. 



Also, in a switched range 
counter such as the K20AW 
model, always begin by 
counting in the upper range, 
This avoids the obvious errors 
that could occur using the 
zero-blanked version (i,e,, 
1,140,003 Hz on lower range 
reads as 03 Hz), I doubt 
anyone looking in a place for 
1 MHz signals would buy the 
03 Hz answer, but, done in 
high range first, he can't go 
wrong, getting first a 1140 
{zero of 01140 blanked) 
answer, to which he adds the 
03 for a 1,140,003 correct 
answer. 

The blanking arrangement 
is easily defeated by a switch 
(if so desired) for high fre- 
quency measurements over, 
in this case, the low range 
limit of 99,999 Hz, Especially 
in audio measurements in 
most model counters, it is 
much easier to read 420 Hz 
or 1 200 Hz, etc, than 00420 
or 01 200. 

To get back to strobing^ 

these same blanking lines can 
be controlled by ripple 
through counting devices as 
in the WB4DCV article (a 
7490 to 7441 pair), and the 
blanking lines will perform 
the "strobe*' function by 
sequentially blanking or un- 
blanking a readout tied to 
that particular IC. Since the 



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4033 Brownsville Rd • Trevose. Pa 19047 
(215) 357-1400/(215) 757-5300 



mm 



exact seven-segment dccodcr 
used may require the 
opposite polarity than that 
provided by the 7441, the 
outputs from the 7441 may 
be tied to the inputs of hex 
inverter ICs to reverse the 
"sense" of the outputs (two 
ICs being rcquiredp with two 
ptes or inverters left over). 
Just remember, to get true 
strobing where only one 
number is on at a time, make 
sure your outputs (from 7441 
or inverters) cause all 
numbers to be off except the 
one to which the counter 
(7490) has driven the 744 L 
Note the following example* 
It is further recommended 
thatj on a 5 digit counter like 
the K20AW model, the 
blanking lines be tied to all 
the decoder even or odd 
number outputs (or their 
inverted noi-lines for some 
seven-segment decoders) of 
the 7441 decoder. This allows 
the following sequence in an 
all* tied-lo-odd-lines version 
(7441 positions): (0) no lights 
on - NLO; (1) one light read- 
out) on - OLO; (2) NLO; 
(3) OLO; (4) NLO; (5) OLO; 
(6) NLO; (7) OLO; (8) NLO; 
(9) OLO — and you have 
strobed 5 digits (count alt 
OLO positions). Between 
digitSj there is no power 
drawn, and, in 5 positions of 
the decoder 7441, only one 
readout is lit. If you are 
modifying a present counter, 
just leave the power supply 
for the tamps alone after the 
modification — it will just run 
cool for long life. If designing 



a new project, take the 
reciprocal (1/x) of x number 
of readouts used, times the 
current per readout (7 limes 
the per segment figure in a 
seven-segment device), times 
two> The times two is a safety 
feature that should appear as 
a K5 to 2-0 figure in all of 
your power supply designs, 
unless you like the smell of 
smoke (transformers, 
resistors, etc.), 

A recent development of 
my own may also be of 



eye, so they appear to be 
always on (see Fig. 1 ), 

Now some comments on 
counters in general, and 
specifically the K20AW 
model I have. Mine has 
been in constant use since I 
built it over three years ago. 
One of the modifications I 
sugg^ted in my original 
article was (as Peter Stark 
K20AW pointed out) con- 
trary to good TTL practice, 
but the entire counter has 
worked perfectly as described 



By all means strobe, but don't make a 
hard job of it when you need not! 



interest. By simply tying the 
D line output of one of your 
crystal timebase dividers 
whose frequency is 100 to 
1000 Hi to all inputs of a hex 
inverter IC (I used a 7406), 
and tying one each of the 
outputs to one of the blank- 
ing lines of the 7446s, an 
alternate means of strobing 
occurs that gives you an 80% 
reduction in power required. 
This may be adequate in 
some applications, and cer- 
tainly requires the minimum 
of hardware. In this case all 
readouts are off 80% of the 
time, and on 20% of the lime, 
but at a rate faster than you 
can follow with the human 



for over three years now. I 
havCj since writing my af tide, 
made some of the modifica- 
tions to my counter that have 
appeared in subsequent 
articles by Pete and others. 
One of these is the input 
circuit change by Pete himself 
in the Nov 1 974 73 Magazine, 
This, coupled with the change 
from a 40673 FET to a 
3N200 FET, greatly 
improved the input sensi- 
tivity. If I had it to do all 
over again, 1 would make this 
input circuit a plug-in module 
of some sort, since t am now 
building the WB2DFA Ham 
Radio input buffer circuit for 
comparison. Either way, I 




^?^rder now 



will use the input metering 
circuit of that article, as a 
little metering would sure be 
reassuring at times, 

I had some months ago 

changed the first 7473-7490 
combination in the counter 
chain over to a 74196 as in 
the VVB2DFA circuit, and it 
did indeed count to 63 MHz 
on mine, using a discrete 
buffer after the 3N200 to 
shape the waveform for TTL 
(instead of the 7413) and a 
74S00 for the input selector 
IC. I have since tried the 
74S196 for the 74196 (pin 
for pin OK), and using the 
same 74S00 I can count to 
just over 100 MH?,. I have 
determined that the 74S00 is 
the limiting factor, and, if 
you try the same idea, the 
results may vary from 80 to 
120 MHz depending on your 
choice of 74S00 and 74S196. 

I have not laid this out as a 
construction article, but for 
those of you who want to see 
my 3N200 arrangement, etc, 
on paper, please send an 
SASE and Til copy up a sheet 
or two with all the collective 
information on it. It's all 
there for you to dig out of 
the articles mentioned if you 
have them. 

In a short article like this, 
a pin-by-pin type of descrip- 
tion is impossible, but the 
above articles and their sche* 
matics should straighten out 
any questions or problems on 
what 1 have described. By all 
means strobe, but don^l make 
a hard iob of it when it need 
not be i ■ 






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TRICKS WITH AWTENNAS 

In OUT September, 1975 Issue^ 
ynder New Products, there appeared a 
descriptFOo of a coaxial coupler and a 
remote cxjntrol felay by Inline Instru- 
ments^ liic. We had installed one of 
each, and the results made our 2 
met€f operatkin and UHF listening 
much more interest in^. 

The coupter was inserted Inline on 
tlie c«»xf3J cable at I he transceiver 
and the relay was c^alT^ped to the 
rotattng pole on top of the tower. An 
omntdirectionat vertical was added to 
the lop of the pote and connected to 
one port of the re Jay, and the beam 
was connected to the other port* The 
existing coax carries the energizing 
power to the relay, so nothirK) else 
had to be added. The plug lead of the 
12 volt power supply was run to the 
injection port of the coupler through 
a switch, and the antennas could then 
ht selected (Fig. 1). By switching 
from the vertical to the beam at 
different angles of rotation, side lobe 
response, front'to^back ratio, and 
other reflections were easily noticed 
by direct comparison, We discovered 



the true characteristics of the beam, 
Being by nature rinkerers, we 
decided to try other schemes. Our 
Bearcat III VHF-UHF scanner always 
had low gain on UHF because of the 
single VHF antenna common to both 
bar^ds. The Inline titerature showed 
the relay transfer time to be one 
miiUsecond^ $o it W9% fell that it 
should follow the step response tsme 
of the scanner. A two transistor inter- 
face switch was built up on a vector- 
board and installed in the scanner. 

The coupler was transferred to the 
scanner ooan line^ A UN F antenna and 
[he relay were added to the pole. Both 
antennas were connected to the relay. 
The scanner power supply powered 
the trannistor swHch and the relay 
with no problems. The relay easily 
followed the scanner band transfer 
and formerly noisy UHF sifjna^s 
became full quieting. There was no 
audible noise induced by the relay/ 
antenna switching. The life expec- 
tancy of the reiay is such that even 
with the high rate of switching it 
should last for years. Most other 
scanners use similar crystal and band 



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switching techniques, so the circuit 
shown should be usable without modi- 
fieation. 

Time has prevented more ideas 
from actually being tried out, but we 
woyld like to pass on a few applica- 
tion hints v^ich might surt individual 
requirements. 

First. Repeater antennas can be 
switched by tone from m obiter or 
remote points to provide more favor- 
able selected area communication. A 
timer or second tone can lestore 
fwrmal conditio a 

Second: Two antennas can be 
switched in a mobile to offset u fi- 
des ired directional condtttons. 

Third: Skilled UHF operators can 
install converters, preamps, or 
varactor mutiipliers on the tower near 
the antenna. Both the accessory 
power and the rf is supplied via the 



coax line. A siggested system is 
^lown in Fig. 2. Cable losses are 
greatly reduqed. Note: The relay 
shown is not a remote controi type. 
Since power ts also recfuired at the 
cortverter, a second coupler supplies 
both the converter and relay power 
for UHF operatEon- 

Fourth: FM commonication on 
VHF-UHF uses mainly vertical polari- 
zation. Fixed station to fixed station 
operation, using simplex frequerictes, 
can communicate over longer dis- 
tances by using horizontal polariza- 
tion with minimum Interference from 
mobiles. Horizontal to liorizontal and 
vertical to vertical QSOs can thus be 
carried on at the same time. A hori- 
zontal antenna can easily be added 
with the use of the subject devices. 

it should be rioted that ooaxiaf 
cable is not only costly but adds wir>d 
loading and stress lo a tower or pole. 
Ma^rrtenance will be reduced and the 
shack will be neater with less cablesL 

Installation of the coupler and relay 
showed no apparent attenuation, 
noise or change in swr over the 
VHF-UHF range- 
More information csn be obtained 
hy writing directly to Inline Instru- 
ments, Inc., Box 473, Hooksett MH 
03106. 




IMEW MFJ CMOS-3043 

ELECTRONIC KEYER 

by Morgan Godwin W4WFL 



Except for the omission of the 
model number on the tower portion 
of the front panel, (VIFJ Enterprises" 
new CMOS 0043 electronic 1<eyer 
looks exactly like Its predecessor, the 
C^'IOS'440RS. However, appearances 
can be deceiving. Inside, the elec^ 
tronics of the CMOS-440RS have 
been completely replaced by elec- 
tronics based on the Curtis 8043 IC 
keyer chip. Thus, while retaining all of 
the feature oi the oider model, the 
new cirojitry provides the additional 
advantages of 1) dot memory; 2) 
Iambic operation with external 
squeeze key; 3) variable weight con- 
trol; and 4} r el table soiid state keying 
for grid block and cathode keyed 
equipment and solid state rigs. 



Completely self contained in MFJ's 
standard 4 x 31/4 x 3-3/16 inch 
enclosure, the CMOS'8043 Is powered 
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oscillator utilizes a 2 N 3904 which 
provides ample volume with the built- 
in speaker. Tone and volume are 
adjustable with internal trim pots. The 
unit features self completing dots and 
dashes with jamproof spacing and 
instant start with keyed timebase. 
Weighting is variable with ^n tmBrnal 
trim pot- The speed rarige is adiustable 
from 8 to 50 wpm with a control on 
the rear paneL Also on the rear of the 
unit are the tune otf on-sidetone off 
switch and phono jacks for keying 
output and external paddle. For oper 
ation in the iambic mode an externa] 



124 




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COT 



} 



PADOLt 



1 



IHJ^'^ 



JN34 



/r? 



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lOfiF 



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.01 
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TRIM 



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^^A ■ TO 1 



Fig, h Circuit diagram of MFJ CMOS-3043 efecrnonic keyer. Jack connecrions: A — dot; B — dssh: C — ^id 
block out put; D — direct out put Switch connections: K - std&tone off; H - tune; f - -Vcc; G - ground. 
Other connections: L — speaker; B, F — speed comroi; M — ^Vcc. 



squBe^e-type keyer paddle Is 
necessary. Also, operators who, Ilka 
thfs writer, are real key thumpers, will 
pmbably prefer art external paddle 
with a weighted base to keep h in 
place during use. 

Its small size, light weight and self- 
contained batteries should make the 
CMOS 8043 especially popular with 
campers, backpackers and DXpedition 
types who have learned to make every 
cubic tnt^ of space and ounce of 
vveight count. It also merits the atten^ 
tion of stay at home, fixed- station 
operators, whether their operating 
preference be traffic handling, DXing 



K 



t 






















^ 




tj 








, A 


*T 








4-^CC' * 








T" , 










^^ 








H TU 



ftfA9 VLrw aF4T SWITCH 




r&P yi(w 



Fig. 2. {a} Bear view showing connections to DP4T function switch, (bf Top 
view showing position of p&ddle, adfustable trim pots aod ^rious circuit 
conne ctioris^ 



or fust old-fashior^ed ragchewing. 
Priced at $39,95, the CMOS-8043 
electronic keyer is available from 



dealers or direct from MFJ Enter- 
prises, P.O. Box 494, Mississippi State 
MS 39762. ■ 



KENWOOD TS-70M 

2 METER TRANSCEIVER 

By Fred Goystein WA1 WDS 

Two meters has come a lon^ way 
since the days of Twoers and Gooney 
Boxes. While FM is ttie most popular 
mode of actrvity, there's plenty of 
SSB and even CW on the band nowa- 
days, particularly in the OSCAR seg- 
ments. 

It takes a pretty good radio to get 
full enjoyment out of the band, and 
the Kenwood TS 700A is more than 
just a pretty good radio. Full band 
coverage is provided if> four segments, 
with VFO or crystal controi- You get 
FM, CW, upper and lower sideband, 
even AM, Power output is conserwa- 
lively rated at ten Watts, The built-in 
powwer supplies are for both 117 V ac 
and 12 Vde. 

The design is quite modem arKJ 
innovative. On SSB, the unit is sir>gle 
conversion, with a crystal lattice filter 
at the tO,7 MHz i-f. The crystal 
bandswitched oscillator is premised 
with the 8 MHz VFO ar\d extensive 
bandpass filtering provides very (ow 
spurious response and emission. For 
FM, a second if at 455 kHz provides 
additional selectivity and improved 
audio recovery, 

Kenwood didn^t spare expense 
when it came to putting in the filters. 
There's a 20 kHz crystal fitter coming 
out of t^ first mixer into the noise 
blanker. The blanker compares the 
nofse across tfiat bandpass with the 
noise within the SSB baridpass. and 
the blanking action is amazingly Qood. 
There's probably at least 30 dB of 
blanking available, if the noise gets 
bad enough. At my QTH, it newer was 
strong enough to get through the 
blanker, and my other FM rig is driven 
batty by passing cars and trucks. 
When the SSB Is less prone to noise 
than an FM receiver, that's a good 

blanker! 

Coming out of the blanker, the SSB 

is cleanly tailored to its bandpass and 

sent to the i-f amplifiers and detector. 

For FM, the signal is converted down 

to 45S kHz, where two ceramic filters 

result in pherromenal selectivity. 

Splinter channels are no problem 

whatsoever with the T$-700A. I cotjid 

listen to 146.625 and hear nothing 

but an occasional splatterir^ voice 

peak even though the repeaters on ,61 

and ,64 are very strong here. This is 

even better thgn ihe results I had with 

other expensive synthesized rigs. If 

everyone had a radio this sharp, the 2 

meter band wouldn't seem half as 

crowded as it does now. 

Not that the sensitivity isn't good, I 
was hearing signals on the TS-700A 
that most other radios couldn't tell 
were there. The VFO helps, too, since 
there are no "secret'' frequencies with 
or». For repeater use, the transmrner 
is 600 kHz low in the 146 portion, 
600 kHz high in the 147 portioa 
Putting the repeater switch on 
"reverse'* inverts the operation, which 
is necessary for California plan 
inverted splits. 

The VFO calibration is good within 
1 kHz across the band, and the center 



125 



tuning position on the meter helps put 
you right on frequency. Ttiere'sa 100 
kHz crystal calibrator |ust in case you 
like to be exact. The unique 
"S meter'* circuit helps lyntng on FM, 
too. The meter is left on the SSB i-f 
^trip, so the repeals carrier has to be 
within the SSB bandpass to get a 
reading. The meter doesn't pin on 
strong signals like on most FM tfgs, ^ 
yoy can ^ccur^tely give a signal 
strength report or turn the beam using 
the meier as a guide^ 

If tuning a VFO while mobile seems 
g btl too difficult, thore Is room for 
ale wen crystals. Since each crystal is at 
the VFO equivalent frequency, there's 
no need to use separate receive and 
transmit crystals. If your area has a 
repealer with 146.46 In and 147.06 
QUI, a crystal for T.006 MHz above 
the bottom of the 146 segment will 
put you there. Toning in 147.06 
would normally result in a 147.66 
rBp^ter input, so you need the 
crystal. If your area conforms to the 
usual American bar^dplsn, you don't 
need any crystals. 

There are other §ood features to 
the TS-700A. There are several 
var actor- tuned stages. Including the 
front end, that optimize performance 
as you chariga band segments. The 
final has a tuning control, and there's 
even driver peaking, so you don't have 
to worry about fosing sensitivity at 
one end of the band or the other. 
VOX is available as an accessory. If 
you really want some fun on two 
meters, the TS 700A wdl realty 
deliver. 




®(ga^iL i^ns^ 




COLUftflBUSGA 
MAY 8-9 

The Columbus Amateur f^adio Club 
(Georgia) is holding its annual Ham- 
fest on Saturday and Sunday, May B 
and 9th. Tlie hamfest will be at the 
Fine Arts Building, Columbus Muni- 
cipal Fairgrounds, Columbus, Georgia- 
For further information contact 
Dennis Hand, Jr. K4ICR, Route 1, 
Box 172A, Cataula GA 31804, 



AM BOY IL 
APRIL 25 

The Rock River Hamfest wiU be 
held April 2B, 1976, Amboy, Illinois 
Lee Co. 4'H Center Jet. 30 St 52. 
Same place as East year. SI advance, 
gate S2, write Carl Karlson W9ECF, 
PO Box dS, Nacbusa. Illinois 61067. 
Barn or shine - indoor or mjt, 
campirtg, large swap shop, food, and 
many priie^. Short trip west of 
Chicaqo. Talk-In 146.94, 



SULLIVAN IL 
APRIL 25 

The MouUrie Amateur R^dio Klub 
announces its 15th Annual Hamfest at 
the American Legion Pavilion in 
Wyman Park, Sullivan, Illinois on the 
25th of April, 1976. Flam or shine, 
same plaoe as always. 



CADILLAC Ml 
MAY 1 

The Wexaukee Amateur Radio 
Association announces their 16th 
Annual Swap Sfiop and Eyeball that 
will be held May 1st in the National 
Guard Armory in Cadrllac. Michipn. 
starting at 9 am> This Swap Shop is 
open to all radio amateurs^ citizens 
banders, one J anyone Interested in 
radio communications. Lunches will 
he available at noon and there is lots 
of free parkir^g. Tickets available at 
the door. 

MEADVILLE PA 
MAY 1 

The Northwestern Pennsylvania 
Swapfest will be held May V, 1976 at 
the Crawford County Fairgrounds, 
Meaduille PA, Free admission. Si to 
display. Flea market begins at 10 am. 
Hourly door prizes and refreshments. 
Commercial displays welcome. 
Indoors if rain. Talk !n 146.04/64 and 
146.52 MHz. Details: Crawford 
Amateur Radio Society, Box 653, 
MeadviJle PA 16335. 



BIRMINGHAM AL 
MAY 12 

The Annual BirmirTghamlest Anra- 
teur Radio Convention wilt be held 
May 1 and 2 at the Alabama State 



Fairgrounds in Birmtngham, Head 
quarters hotel Sheraton downtown 
(on 1-6S). Features: gtant two^ay 
indoor fDut door swap circle, manu- 
facturers' exhibits, forums, displays, 
family activities, prices fpEore, Free 
Saturday night party, much morel 
Talk-in: 34/94 ^WR4ADD), 3965 
kHz. Information: B.A.RX., PO Box 
603, Birmingham, Alabama 35201. 
Sheraton r e servations: 
1 800 325^3535. 

KANSAS CITY MO 
MAY 2 

The P.H.D, Amateur Radio Associa- 
tion, Inc. will sponsor tfie Seventh 
Annual Northwest Missouri H infest 
Sunday,. May 2, 1976 at the Kansas 
City Trade Mark, Exhibit Hall 3 [Qtd 
Municipal Airport Terminal Butldmg) 
starting at 9 am. Admission $1.50 in 
advance, S2 at door, Refreshments 
avatlable; swap tables for a fee; 
forums, contests, prizes, commercial 
exhibits, women's and children's pro- 
grams. Talk-in on 34/94 and 3925. 



WESTMINSTER MD 
MAY 2 

The Potomac Area VHF Society 
will hold their annual hamfest on 
Sunday, May 2, 1976, at the Agricul- 
tural Center in Westminster, Mary 



briefs 



The FCC continues on its course of deregulation as Docket 20636 (see page 
148) proposes deletion of rules concerning portable and mobile operation. The 
proposal would permit amateurs to operate portable or mobile without advance 
notice to the Commission and without having to identify as such. FCC 
monitors in several states have been citing amateurs for such violations as 
signing "mobile" instead of "mobile eight"; Washington apparently feels 
enough is enough. 

In otfier FCC news, it appears that ASCII S-level teletype code will be 
permitted in itie very near future. Results from the AMSAT Special Temporary 
Au^xarization for ASCII on the OSCAR satellites have been favorable, while 
computers sre becoming more ar>d more popular among hams. Also, the 220 
MHz C8 proposal is dead, While it is probable that CB vvill be graniedi new 
frequencies, they won't be taken from hams. 220 MHz repeater acttvity is 
growing rapidly in many areas aruj is almost on a par with 2 meters in some 
areas. 

One very probable place for CB expansion is on eleven meters. While there 
has been a rulemaking under consideration for some years to provide additional 
channels for CB sideband operation, the number of scof flaws operating above 
27.3 MHz has been increasing rapidly, using bogus call numbers in the *'HF" 
series as welt as making up others. The FCC has been unable to handle the 
problem^ legaiixation of the so-called *'HF" bar»d may result. 

Gus Browning W4BPD lias departed on another DXpednion comparable to 
the one he took over ten years ago. He promises to visit as many countries as he 
can afford to: Bhutan will receive special attention as Gus will be helping the 
governmient of thai remote Himalayan kingdom to modernize their communi- 
cations facilities, 

Rtipeater/police interface idea catching on; groups in various areas are 
contemplating following the lead of several Chicago area clubs whose systems 
have a direct touchtone activated tie line to the 91 1 dispatcher. Hams are thus 
abte to treat autopatches as a public service rather than simply a convenience; 



this should counter some of the criticism received due to questionable uses of 
autopatch, Hams and the FCC are both uncertain as to what is considered 
acceptabl& on an autopatch, with citations given out in some areas for practices 
considered acceptable in others, 

Good publicity for amateur radio in various newspapers, as WA2CFA and 
otfiers arrarige for emergency shipment of medicine to Ecuador to help save the 
life of a VA year old girl, A New York Times story described the efforts of the 
various parties to rush the drug to South America, with ham radio getting the 
leading role. Hams' massive Guatemalan effort lias also generated great PR, 

Microprocessor technology h leaping ahead with National Semi conductor'! 
announcemen) of tfieir new SC/MP chip. While slower than sorrte other 
microprocessors, the SC/MP (simple, cost-effective microprocessor J is designed 
to sett for under ten dollars and require a minimum of interfacing. The object is 
to have a microprocessor included as a component in devices that ordinarily 
wouldn't, such as cash registers and appliances. Most hobbyist applications 
don^t require much speed anyway, so the day of the hundred dollar computer 
system can't be far off. Other microprocessor prices are falling; Texas 
Instruments has announced their TIS080 chip, equivalent to other 8080 chips, 
with a price of under $35 in single quantities, 

A "Treasure Hunt" coordinated by the Keene (WH) Radio Amateur Society 
recovered two sacks of canceled checks stolen from an interstate bus while en 
route to the Cheshire National Bank in Keene. About fifty Boy Scouts, with 
ten ham mobiles using 146.52 for communications, helped find the checks 
which tfie thieves, wfio thought they were taking cash, had ditched in the 
woods in Wi richest er. 

The FCC has acted on Docket 20T19, shiftir^ the huridrcd milliwatt "walkie 
talkies" that may be operated without a license from the 27 MH? Citizens Band 
to 49.82 49,90 MHj. Manufacture of the CB units may continue for a year; use 
will be permitted untri 1983. 



126 



land, between the hours of 9 am and 5 
pm. There will be a reg-stration of S3, 
TaJk-ln on 14B.94 and 52. Far more 
Information contact K3DUA or 
WA3NZL 

BROWNFIELD TX 
MAY 2 

The Brown fie Id 76 Centennml 
Swapfest will be held an Uby 2, 1976 
In the Natiortil Guard Armory, 
Brown field. Testes. Door prizes will 
Include a 2 meter FM r^g and a 
Johnson Messenger CS transceiver. 
Advanced registration SI. 50 and 
$2.00 at the door. Social get together 
the evening l>efore in the Armory. 
Write Viola Simmonds W5FBM, 1603 
E Tate St., Browr^Neld TX 79316 for 
info and/or fegifiration. 

SEABROOK NH 
MAY 8 

The Hosstraders Third Annual Tail- 
gate Swap lest vi^ll be hetd Saturday, 
May 8, at 11 am at Addams' CamR 
ground, Route 236, Seabrook IVH off 
Route 95 at the fVlass NH border. 



Admission 75^^ dealers included, no 
commissions or percentages. Excess 
revenues benefit March of Dimes birth 
defects campaign. FM clinic sponsored 
by Saddleback f^epeater Association. 
Talk in .52. ,40 00, and/or 3940 kHz, 
Jf any questions, SASE to WA1 IVB, 
Sox 32, Cornish, Maine 04020. 

FORT WALTON BEACH FL 
MAY 9 

The Piaygroynd Amateur Radio 
Club will hold tis Si^th Annual Swap- 
fest Sunday. May 9. 1976, from Sam 
until 4 pm at the Fort Walton Beach 
Fairgrounds, Registration SI. 50 
advance — $2 at door. Free swap 
tables. For hotel and other informa- 
tion write: Swapfest Committeep PO 
Box 873, Fort Walton Beach FL 
32543. 

JAFFREY NH 
MAY 15 

The 1st Annual Fly In and Flea 
Market will be held Saturday, May 15, 
1976 at the Jaffrey Municipal Airport 
(Silver Ranch) irr Jaffrey, New Hamp- 



shire. 73 MBgsiine will fxist the event. 
Picnic facjlitie*. food stand, great ice 
cream, horseback riding available at 
Silver Ranch stables across the road 
from the airport (200 yds). Plenty of 
hangar space for exhibitors, etc, Come 
one - come all — if you can't fly — 
dni^t — but gpt here, Jaffrey is 6 miles 
south of Peterborough on U.S, Rte. 
202. 

WEST LIBERTY OH 
MAY 16 

The Champaign Logan Amateur 
Radio Club is holding its Gth Annual 
Flea Market and Auction on May 16, 
1976 starting at 12 pm at the West 
Liberty Lions Park at West Liberty, 
Ohio. Free admission, trunk sales and 
tables $TOD, door prizes. Talk in on 
146.52 and 146.13/73. 

LAKE DELTON Wt 
MAY 22 

The Yellow Thunder Amateur 
Radio Club will sponsor their 6th 
annual hamfest on Saturday, May 22, 
1976 at the Dell View Hotel in Lake 



Oelton, Wisconsin, starting at 10 mm. 
Meetings ^id events incfyde: swap 
shop, DX VHF, RTTY, MARS;, 
ARPSC, hidden transmitter hunt, 
tadies activities, liars contest and an 
evening banquet with entertainment 
including something new: "The 
Kitchen Maids." Grand prize: 
Regency HR2-8, Admission S7 in 
advance or $7.50 at the door. {Si. 50 
or S2.0O witfiout the bariquet.} For 
further information contact Kenneth 
A. Eboeter K9GSC, 822 Wauona 
Trail, Portage Wl &:^0T 

SANDUSKY OH 
MAY 23 

The Vacation land Hamfest will be 
held on Sunday, May 23, 1976 at the 
Erie County Fairgrounds from day- 
break till 3 pm. Featuring • free 
camping Saturday ni^t, free U'anspor- 
tat ion to Cedar Pomt ferry boat dock. 
Bring the family arKi let them visil ihe 
greatest amusement park in the U.S.A. 
Plenty of ffea market tables, dealers 
welcome, 8 acres for trunk saies. 1st 
grand prize: 1200 Wan ac gasoline 
generator. Tickets are ST50 in 





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wired and tested. Drop us a line or give us a call today. 

HtlfCO - P.a Box 357, Dept- 25, FVovo, Ut, 84601 -(801 } 375-8566 



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127 



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immwfiau Miipmeni DafllBr inquirMra initfivd. MtcKigan r«iid*4iu add 




advance - %1 at gate. Fl^a market 
v^ides SI each. For further informa^ 
!»on or reservations writer E.A_R,S., 
PO Box 2037, Sandu^y, Ohio 44570. 
Call in on 52-52- 

WABASH tN 
MAY 23 

The Wabash County Amateur 
Radio Club Mill ho^d their 8th Annual 
Hani test Sunday, May 23, 1976 at the 
4-H Fairgrounds in Wabash^ Indiana. 
The hamfest wiil be held rain or shine. 
There will be a large tlea market (no 
table Of set-up charge), technical 
forums, bir>go for the XYLs, free 
overnight camping with ac hookup, 
and plenty of parking^ Lots of good 
fcxjd at rea^nab^e prices. Admission 
ts $1.50 for advance tickets. S2 at 
gate. For more information or 
advanced tickets write to B^ib Mitting^ 
663 North Spring Street. Wabesh, 
Indiana 46992. 

POTTSTOWN PA 
MAY 23 

The Pottstown Area Repeater Team 
Hamfest and Flea Market will be held 
on Sunday, May 23 at 9 am to 4 pm 
at Rt. 422, Hi way Drive-in 8 miles 
east of Pottstown. There will be 
prizes, auction, contests, and refresh- 
ments. Talk in 52/52, 81/21, 66/06. 
Registration S2 — tailgate $1. For 
more information contact A. Jeffer- 
son WA3VYS, 444 Roland Avenue, 
PottstownPA 19464. 

KNOXV1LLE TN 
MAY 29 30 

The Radio Amateur Club of Knox- 
ville win hold its annual Greater 
Knoxville Hamf^t oit May 29 and 
30th at ttw Kalional Guard Armory, 
3330 Sutherland Ave,. N,W. Activrtles 
will include an indoor and otrtdoor 
f!ea market. Door admission Si and a 
chance for a door prize. Tables and 
space rental for indoor flea market 
will be $2.50 per table- There will be a 
banquet on the 29th at 8 pm at 
Hovi^ard Johnson's, West Town at $6 
per person. Talk-in on 16/76= 34/94 
and 39^. More in tot mat ion by SASE 
from Edward U Mekon WB4JGF, 749 
Elkmont Rd., Concord TN 37922. 

BURLINGTON KY 
MAY 30 

The Kentucky HamO-RafTia will be 
held Sunday, May 30, t976 {Me^ortal 
Day weeker>d} at Boone County Fair- 
grounds, Burlington. Kentucky, Ten 
minutes south of Cincinnati^ Ohio 
near I 75. Priies, forums, XYL pro 
gram, exhibits ar^d flea market, 
Tickets $1.50 advance, For more 
Information coniaci^ NKARC. PO 
Box 31, Fort Mitchell, Kentucky 
41017. 




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t28 



An Authorized Bicentennial Program of 

73 MAGAZINE 



Show "four Pride 
In America's Past, 
^ur Faith In Her Future 



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Everything in Ham Gear - for over 37 years 



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Reference 

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DIPOLE ^ANTENNA CONNECTOR 

HVE-QUE iH&n dIpolB eonrwctor 
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yo^vurul tMio Co- Oevt si 

So J Z6a4i El Pito. Ti rn2& 
t*lepri£Sfle f9i5l »?-m*i 



HO to 6 Metpirs plus imi 5 SWL Bands 
eui1i-1rt balun, 1 KM EWi ratlnrj, 

ao to ItO ft iinrirtdd'V or HorizQi'a] . 
Avii little in kit fmn or dfio^ie^, 
ill 3DIC 154. 9S ciih PPO in USA, 

ut eR*if with 100 ft B/ir r«B t 

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flrdir direct. M;t^t*r CMr^ accet^tr^ 

^"' itamped pnvnlope for InfcreaticiTi , 



Charlene Knadfe WB2HJD 

316 Vanderbilt Parkway 
Dix Hills NY 11746 



I decided to improve the 
hamshack. The O.M. was 
out and there couldn't be 
a more perfect time. The 
Fibber-McCee hamroom 
closet wa5 sixty percent 
empty. O.M. and friends 
were on a mountain- 
topping expedition, and 
they'd packed like it was 
for forever I had time. 
They would be gone the 
entire weekend. 

Lug the rest of the 
heavy stuff out of the 
closet. Clean the floor — 
hadn't been vacuumed 
since we moved in (too 
eq u i pme nt-co vered] . 

Bring up a steel-shelf unit 
from the basement. 
Wouldn't miss one there. 
Put it in hamroom closet. 
Fits fine. Lug the heavy 
stuff back into closet — 
this time onto lowest 
shelf. 

Add another bookcase 
— this one wood-grained 
and handsome. Fill it with 
QSVs, 73's, Ham Radio's 
and CQ's (O.M. needs 
them for quick reference 
whrle on the air) so there 
won't be space left for 
voltmeters, power sup- 
plies, and supply sup- 
plies. 

Dust and wax desk and 
two tables « Clean floor. 
Stand back and admire. 
What could be better than 
this? Something could. 
There could be an acousti- 
cal ceiling. 



1^ 



Too bad I thought of tt, 

OM returns aghast and 

delighted Adds pegboard 

back to closet. Puts things 
on shelves neatly. Devises 
wire-hanger for side watL 
Progress! 

Pass the word I want 
egg boxes to use as 
acoustical tiles. N A STAR 
office says they seem to 
work (NASTAR, we re- 
member you), though they 
never measured to be 
sure. Friends and rela- 
tives give egg boxes. 
Especially Grandmother, 

whose friends run a deli- 
catessen. Can't just tack 
them up. Got to paint. 

(Worst mistake). 

Line basement floor 
with newspapers; spread 
the cartons. Dab the 
paint, twist; dip, dab, 
twist Slow going. Must 
be a better way. An idea 
lights. Use an insect 
sprayer. Cot one for 
$2.39, 

"Why don't you just 
buy ceiling tiles? The 
suspended ones are 

great." 
"The idea fs to do this 

cheaply/' 

"Have you considered 
your labor?" 

' ' I want to do something 
different. Be creative/' 

"You don't even know 

if it'll work/' 

"We'll measure it/' 

"Why paint first?" 
"I've already started. 
Leave me alone/' 

Remove insect-sprayer 
cap. Hole small. Sacrifice 
soup ladle and kitchen 
funnel. Fill it. Pushf Hard 
going. Clogs. Paint too 
thick; hole too smalt 
Scratch $239 plus ladle 
and funnel. Back to the 
brush. Dip, dab, twist; 
dip, dab, twist. This is 
going to take forever. 

Six painting sessions 
later, enough done to 
cover one fourth of ham- 
shack ceiling. Tall stack 
unpainted; short stack 
painted, wet ones on floor. 



Enthusiasm not lost, 
just new projects gained. 
Let it ride. Months later: 
"I'm not so sure I like the 
idea. Why don't you drop 
it/' 

"Never. After all those 
people contributed car- 
tons? After all my work?" 

"Think of what there is 
yet to do " 



( did. And 1 didn't do. 
Too many other things. 
(Sew, study, have another 
baby J 

Rain seeps into base- 
ment. Dries. Seeps again. 
Dries, O.M, disgusted 
with clutter there (of all 
places). Goes on binge. 
Cleans unmercifully. Fills 
garbage cans. Sells valu- 



able gear I'm busy up- 
stairs, 

"By the way," (weeks 
later) **1 threw away those 
old egg cartons. It would 
never have worked. And you 
weren't going to finish them 
anyway/' 

Could he be wrong? 
(Might it work?) Anyone 
want to find out? * 



f 



ATTENTION METRUM II 
OWNERS 




VAJVGVARD has a high quality 
synthesizer made for your rig. 
You get 2,000 thumbwheel 
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With the Metrum, one Vanguard 
synthesizer covers both transmit 
and receive frequencies* 

For complete details and photo 

see our ha If -page ad in this maga- 
zine. 

VATSiCUARD I.ABS 

196 23 Jamaica Ave.. Hoiln. Nffw Vo4i 1M23 



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(303>4SS-5444 



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IC sockets may be assorted for quantity 
discounts, t to 9 pes. NET, 10 to 24 pes, 
LESS 5%, 25 to 99 LESS 10%, 100 to 
499 LESS 20%. WRITE FOR LARGE 
QUANTITY QUOTATIONS, D.LP. plugs 
and covers also available. 



MINIATURE 

THUMBWHEEL 

SWITCHES 




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BCD ONLY ... 
COMPLIMENT ONLY, 

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DECIMAL 

END PLATES (PAIR) .. 
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VtSI T US WHEN IN ST. L GUIS OR DENVER 



133 



Robert I- Anderson W8KZM 
391 Pleasant Ridge Ct. 

Saline MI 48176 



555 Timer Sweep Circuit 

for SSTV 



The circuit described in this article uses a 
555 timer IC chip as both the oscillator 
and linear sawtooth generator circuit tor an 
5STV monitor. Most SSTV monitor sweep 
circuits that have been published use a 
transistor -discharged capacitor sweep circuit 
to produce the 15 Hz and 1 /S Hz sawtooth 
waveforms required for horizon tai and 
vettica! 4ef lection. Separate oscillator 
circuits arc required to drive the discharge 
transistors to produce a raster in the absence 
of sync pulses, or else the beam v^ill stay at 
maximum deflection until sync pulses 
return. 

I have been intrigued for some time with 
the 555 and its versatility in many applica- 
tions. So, when I was building my SSTV 
monitor^ I decided to experiment to see If 
the 555 could be successfully used as both 
the linear ramp generator and oscillator. 

The entire sweep oscillator circuit 
described uses a pair of 555Sj one For the 
horizontal sweep, and the other for the 



vertical, A single 556 chip, which is merely 
two 555s in a single 14 pin DIP package, 
could also be used. 

The 555 Timer 

For those not familiar with the 555, let 
me first describe its basic design and use as a 
simple oscillator. Such information is basic 
to the understanding of the SSTV sweep 
circuit. 

A block diagram of the 555 is shown in 
Fig. L It contains a precision voltage divider 
string consisting of three equal resistors, two 
comparators! and a control Flip flop. Also 
included are an inverting buffer amplifier 
capable of sourcing or sinking 200 mA and a 
discharge transistor whose collector is avail- 
able at pin 7, The comparators set or reset 
the control flip flop when their inputs are 
equal to 2/3 or 1 /3 of the supply voltagCp 
respectively. When the flip flop is in the 
*'set" condition, the output on pin 3 Is at 
ground and the discharge transistor is "on'' 




.OUTPUT 




O V 



Fig. 2. Basic oscfflaton 

in the saturated condition* The 555 is 
available in an eight pin "Mini -DIP" package 
or in an eight lead TO-5 can. 

Basic 555 Oscillator 

The use of the 555 as an as table oscillator 
is shown in Fig. 2. Circuit operation is as 
follows: Upon application of the supply 
voltage, which can be between 5 and 15 
voltSj capacitor C[ will start to charge 
through R\ and R2. When the capacitor 
voltage becomes equal to 2/3 of the supply 
voltage, the threshold comparator sets the 
control flip tlop, turning on the discharge 
transistor. The capacitor then discharges 
through R2, until its voltage is equal to 1/3 
of the supply voltage. The trigger com- 
parator then resets the flip flop, turning off 
the discharge transistor^ allowing the cycle 
to repeat. The waveforms produced are 
shown in Fig. 3. Since the comparator 
switching points are directly determined by 
the supply voltage, which also determines 
the charging rate of the capacitor, the 
oscillator Frequency is insensitive to changes 
in the supply voltage. The oscillator fre- 
quency can be calculated by: 



f = 



K44 



(Rl + 2R2) Ci 



Fig, /, Blocl^ diagram of 5S5 Timer Chip, 



Capacitor C2 is merely a by-pass to keep 
noise out of the reierence voltages. 



134 



8 



I 




2/3 V 



1/3 V 



Tine 



Fig. 3. Osdi/ator wa¥e forms. 

Linear Sweep Oscilbtof 

This basic circuit had some basic 
deficiencies which made it tnitialfy unsuit- 
able for SSTV sweep appflcatfon. The main 
objection was that its output waveform was 
exponent iat rather than linear* The other 
objection, rather minor, was thai it did not 
return to zero but began recharging at 1/3 
supply voltage. Both these problems were 
overcome with the circuit shown in Fig. 4* 

Linear charging of the capacitor was 
achieved by using a transistor constant 
current source in pface of R] and R2. The 
collector current of the PNP transistor is 
constant as long as the capacitor voltage is 
not equal or greater than the base voltage, 
allowing the transistor to conduct normally. 
The transistor operates to maintain the same 



i^ 



SYNC 
PULSE 




O 15V 



.01 yF 



FREQ. 
ADJUST 




TO 
LOW-Z 
INPLfT 



TO 

HIGH -2 
INPUT 



Fig. 4. Basic 555 $^^ep circuit. QI - 2N29Q7 or equiv.; CI - 1 uFhorii., 10 
uF yerL; R3 - tOk fjorii., 250k vefL 



voltage drop across the emitter resistors R3 
and R4, The collector current for a high gain 
transistor (3>300) is for all practical 
purposes the same as the emitter current: 



ii 



^ 



+ 1 



300 

301 



^ 1 



The result is a constant current that can be 
varied by changing R4. The amount of 
current will determine the charging rale of 
the capacitor, and hence establish the 
oscillator frequency. 

To allow the waveform to return to zero 
volts before restarting the sweep, the trigger 



HORZ 
YOKE 




VERT SYNC 
PULSt 



^ HEAT SINK 



Fig. X Comp/ete 555 SSTV sweep circuit 



- IS V 



t^ 



inpui was connected instead to the output, 
pin 3^ through a detay network R5 and C3* 
Approximatdy I millisecond after C] is 
discharged and the output voltage goes low, 
the trigger voltage falj^ below 1/3 the supply 
voltage and a new sweep is started. The 
discharge of C| is quite rapid, allowing for 
rapid retrace. The 1 millisecond delay , how- 
ever, insures that the capacitor does 
discharge completely before starting a new 
sweep. 

In operation, the frequency of the 
oscillator is set by adjusting R4 so that the 
period of Dscillation ts just slightly longer 
than the time between sync pulses. The 
presence of a negative-going sync pulse on 
the 'Vesef input (pin 4) will discharge the 
capacitor for retrace ai the proper time and 
initiate a nev^^ sweep. 

The sawtooth sweop is taken from pin 7. 
This is a high impedance point, and needs to 
b<j buffered with a voltage follower opera- 
tionaj amplifier circuit if it must drive alow 
impedance input circuit. In this application^ 
however, \ was able to drive the positive 
input of the operational amplifier in the 
sweep driver stage without loading problems 
on C] or the current source. 

Summary 

The oscillator circuit is very stable, and 
will run very close to the correct frequency 
If sync pulses are QRM'd or otherwise lost. 
The "retriggering" aspect of its design makes 
it possible for the sweep to lock in again 







i 



I-U^aU V*'''- ' '-' ' 



Home brew SSTV monitor using the 555 sweep circuit. 
new pulse after 



instantly on the first 
previous pulses were lost. 

Fig. 5 is a complete schematic of the 
sweep circuit used in my S5TV monitor. 
Included also in this circuit is a pulse 
"stretcher" and lamp driver that operates 
from the horizontal sync pulses and is used 
as a tuning indicatbr. The cifcoit has been in 



use in my home brew SSTV monitor since 
November 74. The rest of the monitor is 
basically the W9LU0' design. The operation 
of the 55s osci!latGr/ramp generator has 
produced good results and stable pictures 
under many adverse conditions. ■ 

^"A Solid State SSTV Monitor-Mark M," Robert 
Tschannen W9LU0, QSF, March, 1973, p. 27. 



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t37 



LOOKING WEST 



frompa^ 12 

Ramada Inn in Cutver City was oon- 
tacted and they provided a room and 
telephone facilities, A portable two 
meter station, operating under the 
club's W6GAA caltsign. was activated 
from that location on the club's 
WR6ABB repeater and all normal 
r^e^ier activity other than that of ar^ 
emergency rvature was suspended. In 
place of the riormal 'ABB actrvity, a 
PARC sponsored "Guatemalan 
Disaster Relief Net" was called. The 
purpose of thif net M^as to take traffic 
inptit from all over the LA area, 
collate this traffic as to type (i.e., 
priorky. emergen cy, health and 
welfare^ etcl and then disseminate 
same to the proper channels for 
delFvery. Shelly WB6KE0. who had 
already be€n working with the con- 
sulate, was dispatched on a rather 
permanent basis to Set up a portable 
two meter station at their location. 
Wjtti the generous oooperation ot Mr, 
Jotin Smith. Supervisor of Airport 
Operations at Los Angeles Inter- 
nationat Airpoft. space and power was 
made available for a portable station 
to be set up at the Pan American 
Airlines terminai. This station was 
initiated and manned by a non-PARC 
member who volunteered both his 
equiprrvent arHJ time to get things 
started: Mr. Bill Qrenstein KH6IAF/6, 
mentioned earlier in this column, 
along with the assistance of his "date" 
for the evening, Miss Karyn Ericksen. 
Bill and Karyn began ttie airport 
operation around 6 pm Saturday 
aftefTMJon md continued on to about 
5:30 am Sunday morning when feHef 
operators final [y arrived. The Pan Am 
termirial was chosen since they are the 
only carrier from this area with regu- 
larly scheduled flights to Guatemala 
City and were therefore bearing the 
tFunt of the tra report job of t)Oth 
people arKl supplies. Many people 
with relatives were going to that 
lerminal in hopes of finding a way to 
Kfid a messa^ "back home," and it 
was ltx>ught that a stetion set up for 
easy public access would t>e tdeal at 
that location. It was. 

As soon as everything was ready to 



go, Lenore Jertsen W6NAZ, Chairman 
of the Southern California Amateur 
Radio Public Relations Committee, 
was asked to contact the rwws media 
and pass along the location of tf^ 
airport statron arKJ the "CommarKf 
Center" telephone number. In short 
order, the majority of Los Angeles 
broadcast media outlets were carrying 
the necessary Information to the 
public and things began lo get busy. 
While no exact figures are yet at hand, 
in ifie two days that this phase of the 
operatksn took, appnoximately 2,CXX) 
messages wefe collected and placed en 
route to Guatemala in two ways. 
Emergency arxJt priority traffic was 
[mmedtately handed off to stations in 
direct HF contact with Guatemala 
through a number of HF Drsaster 
Relief Nets operating 20 meters 
during the day, and 40 or BO in the 
evening. Through the efforts of 
WB6VDE, WA6IFU and WA6CPS. a 
portable 80 n^ter station was set up 
in tfie Ramada Inn parking tot housed 
in Roy WA6CPS's van; however, most 
of the dforerr>entioned high priority 
was handled by other volunteer 
Stations, many non-PARC members. 
Word had spread quickly as to what 
PARC was doing and the necessary 
HF stations soon made their presence 
and willingness to help known. 

Health and welfare of a non- 
priority nature was handled In another 
way. The majority of it was placed In 
the hands of the crew of an airliner en 
route to Guatemala City virith instruc- 
tions that it be delivered to the proper 
authorities down there. This was done 
to alleviate the strain on the HF nets 
so that they could handle traffic on 
the afore mentioned priority tevet 
Two such padcets went out on 
Sunday the 8th — one at about 9:45 
am and another about 9 pnn with the 
final batch to follow this coming am. 
At around midnight Sunday, this 
phase ot the operation was 
terminated, I say this phase, since 
ther« will be m Of e to come in the days 
and weeks ahead. We witi continue to 
run communication tiaison for tfie 
Consul General, accept and dis- 
seminate return communication, keep 
information on wtiat is transpiring 
headed to tfie media, and anything 
else we are called upon to do. In fact, 
earlier this evening Dan and I found 




1 

* 


^ 


i 

i 




wi 






mmP^ 




1 




W^m 


I 


." r ' 





Recording it si/ at SAROC is the author, as captured m this photo by Mrs, fTF. 



ourselves working hand in hand with 
both tfie GyatemaLan and Par^mantan 
Consul Gene rats weighing relief 
suppli^ in the Pan Am air freight 
tHJildingi prior to shipment. Earlfef, I 
had found my%tf directing people 
who spoke little or no English to John 
WA6HQL, another non-PARC 
member who had been quick to offer 
his services when someone who was 
bilingual in Spanish and English was 
found a necessity at the airport af^era- 
tion. John spent about TO hours 
cramped behind a desk writing 
rT>essa9es m Er^gltsh that were being 
dictated to him in Spanish, 

Then there was Bobbv WAGOBR. 
who made sure that all operations had 
the necessary food to airviwe on. She 
ran around In the rain gathering 
donated food from McDonald's Ham- 
burgers and Shake y's Plz^a so that 
everyone would have lunch and 
dinner. As if that were not enough, 
she also spent about five hours man- 
nir>g a message-gather irxj position at 
the airport facility; the limited 
amount of Spanish that she knows was 
sure handy, Th^ Mm of volumeers for 
this operation goes on and on and 1 
GDuld fill an entire column with just 
names« What's really impoftant, 
{hough, is that when people in 
another part of the world were in 
need of help, people here, antateurs 



such as you, were able and willing to 
provide that help, Not only am I 
proud that PARC took on this human- 
itarian project, but I'm proud of every 
amateur ar^d non amateur alike that 
volunteer^ his or her time to make 
its success unquestionable. 

I think that Karyn Ericksen may 
have summed it up best last evening 
when I spoke with her and Bill at the 
airport, To paraphase what she said: 
When things such as a disaster like this 
take place, one*s instinct is to try and 
find some way to help. What these 
hafn operators are doing is one of the 
finest and most sincere efforts ^e had 
ever seen and stie was ttirilled to be a 
part of iL There was no doubt in my 
mind that she really was impre^ed; 
the excitement in her voice was a 
give-away that she was witness to 
something beautiful. 

Next month; A bunch of wrap-ups 
along with a meeting, so get ready for 
another long one. More on auto- 
patches, the windup on WR6AJP. the 
wind up on SAROC and what that 
beautiful guy Johnny Johnston 
K3BNS told us about future FCC 
plans, and the windup on this story 
afong with coverage of the Febrisary 
22 SCR A meeting in San Diego. Just 
may be some big surprises from that 
one. ■ 



Biii Oremteift KNStAFM relays eanhquake information from Dr. Stark of 
"Food for The Hungry'* (arm of the ftrst mturneesi to the Los Angeles 
GiiStemaian Consu/aie. 




"Operation Savea-f^ation": PARC's portabie star ion at L. A. 
HerB, John S^rreiro WA6HQL translates a health and welfare 
Engiish. More than 3000 messages v^re handled. 



IntemationaL 
message into 



Photo processirtg courtesy of NBC Network Press^ W^t Coast Division, 



138 



I 



BC DIGITONE 



ENC 



• I 



ER 




FEATURES: 

• Crystal Controlled - 
Digitally Synthesized Tones. 

• Low Current Drain CMOS Logic* 

• RFI immune. 

• 16-Button Tactile Feedback Keyboard. 

• Will Interface to Transcervers Using Dynamic Microphones 
with Only Two Wires. 

• Provisions for Three Wire Interface Are Provided. 

• Gold-Plated Keyboard Contacts Pfovided for Maximum 
Ret iabi lily. 

• Operating Voltage Range 9-18VDC. 

• Size: Zr* K 2.1" x .250'^ Without Case. 2,1" x 2.1" x 
.312" With Case. 

• 2'' Square Veicro Available for Convenient Mounting - 
Dashboard - Sun Visor - Radio - Etc. 

Touch- Tone Encoder .,,.,,, S29.50 

Case , . , , , $ 2,00 

Veicro S .50 

• 12-ButtDn Touch-Tone Encoder (Case and Veico not 
Available) . . , $29.50. 

OHIO RESIDENTS ADD 4.5% SALES TAX 
SEND CHECK OR MONEY ORDER TO: 

The Barber Corporation 

P.O. Box 27TA. Waynesville, Ohio 45068 513-097-2926 

Open Tuesday and Thursday Bv&nmgs Unrit 7:00 PM EST 



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Collins 51 6F2 Pow©r Transformer ,,,,,,.,.*...,,,,,».. 85.00 

Hufiter 2000B P*ate Transformer ....,,.. k . 1 25. OO 

Alpha 77 Plate Trarisformer ........,.....,.,,..--. . . 1 25.00 

"All heavy duiy replacefnent transfofiriers are designed to run 
cooler and last longar than the original oquipmeni transformer, 

SPECIALS 

• HIPERSIL PLATE TRANSFORMERS: 3500 VAC at 1.0A 1CAS; 
230 VAC Primary s 6 7/8"H, 8 5/8^'W, 1-3/W'Di 50 lbs.; $t 25.00 

• HIPERSIL PLATE TRANSFORMERS: 3000 VACatO.TA ICAS; 
115/230 VAC Primary; 5-5/8"'H. 8'1/2"W, G-1/2'^D: 33 lbs.; 
$95.00 

• 4'1000A FILAMENT TRANSFORMERS. 7.5 VCT at 21 emps. 
117 V Primary, 4 1/2"H, 3-3/4"W. 4"D. fully enclosed; S27.95. 

ALL TRANSFORMERS GUARANTEED FOR 24 MONTHS! 

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5325 Annette • El f^so, Texas 79924 
Telaphone (915) 568-9702 or (915) 751^656 




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Radio Electronics 



139 



W. Edwin Cain K40RT 
Rt. #1, Farm Estates 
Perry CA 31069 



Tech Manuals 



So! Now you're having 
second thoughts about 
that beautiful piece of 
electronic gear you bought 
at the surplus sale. It's 
beginning to look more 
like a boat anchor all the 
time. But, you say to 
yourself, if I only had a 
technical manual for it, I 
might be able to do 
something besides can- 
nibalize il. Well, my 
friend, take heart. It is 
possible that you can get a 
manual for it. Public Law 
90-23 allows the sale of 



unclassified technica 

manuals directly to the 
public. This article will tell 
you how to go about 
ordering a manual and 
approximately how much 
it will cost. 



Each agency, i.e.. 
Army, Navy and Air 
Force, is responsible for 
determining the releas- 
ability and cost of the 
manuals under its juris- 
diction. In the case of the 
Army and Navy, each has 
a single office where you 



can send your request, but 
within the Air Force there 
are five different activities 
depending on the type of 
equipment involved - 

Determining which of 
the first categories your 
goodie fits in will probably 
be obvious by the type 
sale where you purchased 
the item (Army, Navy, 
AF). If it is an Air Force 
item, you must further 
determine which activity 
in the Air Force can 
satisfy your request. But 
even if you goof and mail 



your request to the wrong 
place, no harm will be 
done, except maybe some 
delay in getting the in- 
formation you want. Each 
service has a similar way 
of identifying its manuals: 
the Army precedes a 
number or group of num- 
bers usually with TM; the 
Navy with NAVSHIPS; 
and the Air Force with 
TO, If there is any 
reference to this type 
number associated with 
the equipment when you 
get it, by all means 



Two 



Times 



TWO-TI IVIING CLOCK & STATION TIMER - 
Drsplays either of two compleielv independent 
ttmes — i,e, — GMT and local lime — any 
CO mtii nation you choose. Clock operates in 
three modes, 12-12, 12-24, or 24-24 hf, and 
includes a station l,D« timer which flashes the 
6 digit UE«D. display at §.5 minute intervals, 
ID timer may be disabled when not in use. 
AC, DC, or Battery operation, emergency 
standby power provisions, .01% crystal con- 
tolled tjmebase and easy to follow instruc- 
tions. Kit includes etched and drilled P.O. 
Boards, instructions, and all parts except case 
and transformer* 

Kit with ,3 in. Displays $45.95 ppd. 

Kit with ,6 in. Displays $5B<95 ppd. 

Wall plug Transformer $ 3;95 ppd. 



6 digit AUTOMOTIVE CLOCK KIT complete 
with a CRYSTAL TIMEBASE accurate to ,01 
percent, 12 volts d,c. operation — built in 
noise suppression and voltage spike protection. 
Readouts blank when ignition h off — draws 
25 mA in standby mode. Has .3 in. readouts* 
Use it in your car or for all applications where 
a battery-operated clock is needed. Approxi- 
mate size 3' x 3.5" x 1J5" 
WITH BLACK PLASTIC CASE $34.95 ppd. 
WITHOUT CASE S29.95 ppd. 

ASSEMBLED AND TESTED $45.95 ppd. 



CMOS CRYSTAL TtMEBASE KITS with .01 
percent accuracy. 5-1 5 v.d.c, operation. Draws 
onfy 3 mA at 12 volts. Single LC, - very 
small size - the P.C, board is 7/8" k 1-5/8". 
Choose 3 main output of 50 or 10D Hz,, 60 
Hz., 500 or IQOD Hz„ or 1 Hz. Several 
related frequencies are also available on each 
bcsard, in addition to the main oni*s listed 
above. Be sure to specify the Frequerwry you 
want. All kits are $10.95 ppd. 



Pong / 



The world's second greatest indoor sport! For 
the price of 240 games of the commercial 
version of pong^ you can enjoy endless hours 
of pong on your home TV, This kit generates 
adjustable ball and paddfes, adjustable upper 
and lower court boundaries^ audio sound 
effects^ and a non-numeric score indicator on 
your TV jet. Includes controls lo allow 
horizontal and vertical paddle movements 
Although the kit consists of standard TTL 
parts, it is fairly complex and requires some 
knowledge of electronics to build it and access 
to an 0-scope to adjust It, The kit comes 
compFete with an etched and drilled, doubJe- 
plated-th rough PX. board, instructions, and 
all parts including control pots, but less case. 
We pay the postage, unless you want it sent 
Air Mail and Insured, which is one buck 
extra* 



TV Pong Game Kit 



$59,95 ppd. 




TO ORDER OR REQUEST INFORMATION WRITE: 



TRADING GO. 




Kits include all parts, instruction sheet, and etched and drilled 
P,C, board. Calif* residents add 6% sales tax. We also carry the 
MM 5320, the 5312, and other chips listed in our flyer. Interested? 
Write for it or circle the bingo card today. 



• Box 3357 San Leandra, Ca 94578 



140 



mention this in your 
request. It may save you 
both time and loot, be- 
cause if an agency has to 
perform research in ex- 
cess of an hour or so to 
locate the number, you 
may have to pay for this 
research. However, most 
research requires much 
less time than this, so you 
don't have to v^orry about 
it. 

The manufacturer m- 
stalls a nameplate on each 
ftem of equipment before 
it is delivered. The name- 
plate contains, among 
other things, the Joint 
Electronics Type Desig- 
nation Number or AN 
number as it is often 
referred to. This number 
tells you what the item is 
and, in the case of the Air 
Force, gives you a clue as 
to what activity is respon- 
sible for the technical 
manual. 

As was stated earlier, if 
it is Army or Navy 
equipment, you need only 
mail your request to the 

appropriate address which 
is also listed at the end of 
the article. If it is Air 
Force equipment, mail 
your request to one of the 
five Air Force bases 
listed, after determining 
the appropriate one by 
reviewing the type equip- 
ment managed by each 
one. 

Now for the cost. It is 
nominal as the govern- 
ment barely recovers 
printing costs. There is a 
minimum charge of $2:00 
for manuals up to six 
pages and an additional 
one-cent-per-page charge 
for all pages in excess of 
six. For example, a man- 
ual with 100 pages would 
cost about $3,00. Be sure 
to specify what type 
manual you want, i.e., 
maintenance, operation, 
or parts list. Do not send 
any money with your 
original inquiry. As soon 

as the agency receives 
your request they will 



determine if a manual is 
available, ff it is, they will 
notify you what the cost is, 
how to make out your 
check or money order and 
tell you where to mail it. 

That's all there is to it, 
so don't let that goodie 
gather dust on the shelf, 
Get yourself a technical 
manual and put it to work. 



ADDRESSES 
Navy 
Director, Navy Pubs., 
Hand Printing Service 
Naval District Washington 
Washington Navy Ship* 
yard 
Washington DC 20390 

Army 
Hq, DAAC*PAS 
Forrest a I Bidg 



Washington DC 20314 

Air Force 
Oklahoma City 
ALC/MMST 
Tinker AFB OK 73145 
Navigation Instruments, 
Flight Instruments, Auto- 
pilots and Airborne Gyro 
components. 
Ogden ALC/MMST 
Hill AFB UT 84406 



r- 




CLOCK KITS14.00 

Includes all parts with MiVI5316 chip, 
etched & drilled PC board, transformer, 
everything except case, #SP284 Si 4 
2/S25 

#SP284S14 2/S25 



5 VOLT 1 AMP REGULATED power supply kit for logic work. AU parts including 

LM 309K #PK-7 S7,50 

DUMMY LOAD resistor, non-inductive, 50 ohm 5 watts 3% STOO 

AA NICAD CELLS brand new, fine biz for handy talkies. $1,25 ea 9/$9.00 

ASCII KEYBOARD brand new w/ROM chip, data package S45.00 



POWER SUPPLY MODULE 

New, plug-in module. Plugs into AC outlet provides 12 
volts AC at V2 amp by two screw terminals. Great for 
various clocks, chargers, adding machines, etc. New 

$2.50 ea. 5/$1Q.OO 





LASER DISCHARGE CAP 

Sangamo, new, 40 mfd 3,000 volts, 180 Joules. May 
be used for filtering, linears, etc., by derating to 
2.000 volts. Shipping wgt 10 lbs, Measures 3% x AVz 
X BV^ inches. $25.00 each 5/$l 10.00 



TELEPHONE TOUCH PADS 

New, by Chromerics, standard telephone format. 
Measure 2% x 3 inches. Great for repeaters, phones, 
computers, etc. S4.50 each 6/S25.00 



C-MOS LINEAR by RCA. brand new, gold bond process. 



1 n -1 


CNt 


* 


•J 


4 % fi 1 


-*i& 


TWv 


mt r 


7 

* 


■ 


9 



301 


S .60 


747 


S ,82 


MM5314 


$3.00 


307 


.52 


748 


.50 


MM5316 


3.00 


324 


1.80 


1458 


.96 


7001 


8.00 


339A 


1.60 


3401 


.80 






741 


.50 


555 timer 


.60 







yffeSn/M^2. 



Please add shipping cost on above. 

P.O. Box 62 

E. Lynn, Massachusetts 01904 



FREE CATALOG 
SP-7 NOW READY 



141 



Cameras, motion and stil! 
picture [af! photo equip- 
ment] 

San Antonio ALC/MMST 
Kelley AFB TX 78241 
Most all general purpose 
test equipment {Lc^ 
'scopes, VTVM's Tube 
testers, etc] 

Sacramento ALC/MMST 
McClellan AFB CA 95652 



Cround communications 
equipment [Navigation, 
Radar, communications] 
motor generator sets, tele- 
type and facsimile equip- 
ment 

Warner Robins 

ALC/MMST 

Robins AFB CA 31098 

Airborne Communications 

equipment [Navigation, 



radar, communication, in- 
terphone] night vision 
equipment and miscellan- 
eous communica tion 
equipment 

NOTE 

It is not possible to list all 
categories. Those listed 
are general and the ones 
in which Hams would be 
nnost interested, ■ 



2 METER CRYSTALS IN STOCK 

We can ship CO.D* first class mail. Orders can be paid by: check, money order. 

Master Charge, or Bank Ameri card. Orders prepaid are shipped postage paid. Phone 
orders accepted. Crystals are guaranteed for life. Crystals are all $5.00 each (Mass. 
residents add 25i tax per crystan. U.S. Funds Onfy 

We are authorized distributors for: Icom and Standard Communications Equip- 
ment- [2 meter) 

Note: If you do not know type of radio, or if your radio ts not fisted, give fun- 
damental frequency, formula and loading capacitance, 

LIST OF TWO METER CRYSTALS CURRENTLY STOCKED FOR 
RADIOS LISTED BELOW: 



!•, Drake TR 22 

2*. Genave 

3«. Icom/VHF Eng. 

4#. Ken/Wilson /Tempo FMH 

5#. Regency HR-2A/HR212/Heathkjt HW-202 



6*. Regency HR'2B 

8«, Standard 146/826 
9^, Standard Horizon 

10». CleggHT-146 



The first two numbers of the frequency are deleted for the sake of being 

non- repetitive. Example: 146.67 receive would be listed as - 6.67R 



L6.01T 

2,6.61R 

3. 6.04T 

4. 6.64R 

5. 6,07T 

6. 6.67R 

7. 6 JOT 
a 6,70R 



9.6.13T 1Z6J9T 25. 6.3 IT 33, 

10. 6,73R 18. 6.79R 26. 6.91 R 34. 

1L6.145T 19, 6.22T 27. 6.34T 35. 

12. 6.745R 2a6.82R 28. 6.94R 36. 

13. 6.16T 21. 6.25T 29. 6.37T 37. 

14. 6.76R 22. 6.85R 30. 6.97R 38. 

15. 6.175T 23. 6;28T 31. 6.40T 39. 

16. 6,775R 24. 6.88R 3Z6.46T 40. 



6.52T 4L7.03R 49. 

6.52R 42. 7.66T 50. 

6.55T 43. 7.06R 51. 

6.55R 44, 7.69T 52. 

6.94T 45. 7.09R 53. 

7.60T 46. 7.72T 54, 

7.00R 47. 7.12R 55. 

X63T 48. 7.75T 56. 



7.15R 
7.78T 
7.18R 
7.81T 
7.21R 
7.84T 
7.24R 
7-87T 



BACK IN 
STOCK! 



CRYSTALS FOR THE IC 230 SPLITS 
13.884444 MHz; ia91?77SMH£. Se.50 



m STOCK: 13.851111 WIH^; 

C3. 



57. 7.27R 

58. 7.90T 

59. 7.30R 

60. 7.93T 

61. 7.33R 

62. 7.96T 

63. 7.36R 

64. 7.99T 

65. 7,39R 



licbivfl 



IC-SSA 



nCHANNLL 

i mttttfrn 

If] WATII 



Spccialf Only $249.95. Get 8 crystab of your 
choice for only $2.50 more with purchase of 
IC22A. 

READY TO GO ON: 



1 94/94 

2 34/94 



3 
4 



22/82 
28/88 



RECEIVER: 



5 52/52 

VHF FM 







♦ - 

* MM 






1 


isti 






+■* 





Reception Frequencies 22 channels for 144 MHz band. 

BijiU-in crystal units fof Schannets, 
Reception S¥*t*t* Oo«Ne Superheterodyne 

J nter mediate rre<iiiencie& 1$t intermediate: 10.7 MHb 

2nd I nter mediate: 455 kHz 
Sensitivity a. Better than 0.4 u v 20db auieting 



1 44,00 to 14SXtO MHz using 22 

channeb 
Tfansistors ,,.,,,,...,,,,. ^23 



Diodes 



* « * * 



.16 



STORE HOURS: MON-FRI: 9A.M .gP.M. SAT: 9A.M.. 6P.M, 




Box 469 

Dept. 4576. Quincy MA 02169 
617^71 6427 




oirrDimoir&D® 





INC. 



SI Dunn K5J RN 
3607 Binkley 
Dallas TX 75205 



RF 

and 

Mod 
Monitor 



w 



rfr 



Ti:HTl 



I. 5* SOT 






1°^ 




■ftttn 



•NO%tl 



Around most ham 
shacks, several uses can 
be found for a simple rf 
and modulation monitor. 
This one is little more than 
a glorified crystal detec- 
tor, but it monitors outgo- 
ing rf, aids in the tuneup 
of transmitters and anten- 
nas and lets you hear how 
your transmitted signal 
sounds. 

Of course, single side- 
band — if the carrier is 
properly suppressed — 
will sound through this 
monitor I ike you're talking 
with a mouthful of wet 
cement. Amplitude modu- 
lated signals should sound 
clean and natural, 

I built this circuit in a 
small phenolic box mea- 
suring 3-3/4 X 2-5/8 X 
1-3/8 inches, A metal 
minibox also can be used. 
The rf probe is 5 feet or so 
of #22 enameled copper 
wire folded and taped into 
a ''whip'' about a foot 
long and soldered to a 
phono plug. At low fre* 
quencies and low power 
levels, a longer piece of 
wire may be necessary for 
sufficient rf pickup. Most 
any germanium diode 
should work, but a 1N87 
gave higher output than a 
couple of other general 
purpose diodes." 



142 



Michael Wheeler WB4YDX 
3259 Roxbury Drive 
Le><ington KY 40503 



A 
Failure 

to 

Communicate 



I may give up ham 
radio. Band conditions 
have been getting pro- 
gressively worse and re- 
cently i^'s been so bad, I 
haven ^t even been able to 
get through a complete 
QSO. 

Last week was particu- 
larly frustrating; for ex- 
ample, on Sunday I was 
talking to a TV weather- 
man out in six-land and he 
told me about a wealthy 
friend of his who'd spent a 
bundieon a fancy antenna 
farm. It had separate 
towers with monoband 
beams for each band and 
the rotors were powered 
by specially designed bat- 
teries. They required a 
critical amount of internal 
pressure which was pro- 
vided by an external 
compressor unit. 

It seems that during the 
recent DX contest this 
fellow left the compressor 
on and the batteries built 
up so much pressure that 
they exploded, sending all 
kinds of debris into the 
air. 

Naturally, when I heard 
about that, 1 commented 
that the skies must have 
been partly crowded with 
shattered towers, due to a 
high pressure celL I figure 



the band must have fallen 
out about then 'cause he 
didn't come back after 
that. 

Then on Wednesday, I 
was up on Twenty, talking 
to a foreign sounding guy 
who kept referring to his 
transmitter as his E- 
mitter. He probably called 
it that because of its A-1 



emissions (they sounded 
pretty good to me any- 
way). He told me about 
a run-in he^d had with the 
local tax collector who'd 
tried to impound his radio 
equipment. When they 
went to court over it, the 
judge, who turned out to 
be the tax collector's 
brother-in-law, told the 



ham to hand over his gear. 

I asked him if the judge 
had a deep voice, and 
when I found out that he 
did, 1 said, ''It's obviously 
another case of a short 
circuit from E-mitter to 
collector due to an im- 
properly biased bass/' 

The band dropped out 
on us. ■ 



If you want to use 

ONE ANTENNA 



There's only 

ONE DUPLEXER 




The Micro Strip Dupiexer 



FOR 2 METERS! 

More than 106 db isolation 
Less than ^3 db insertion loss 
250 watts 
Only $350.00 





FOR 220 MHZ! 
More than 90 db isolation 
Less than 1,0 db insertion loss 
250 watts 
Only $250.00 



FOR 450 MHZl 
More than 90 db isolation 
Less than 1.5 db Insertion loss 
300 watts 
Only $350.00 




Call or write for our free catalog of 
Duprexers, Filters and Helical Resonators 



^ 




WTV 



105 No. Amphlett Blvd. 



San Mateo, CA 94401 



(415) 348-3858 



143 



CONTINENTAL SPECIALTIES 



PROTO BOARDS 

Bui-Id ii test cErcuiCS^s fail a» vou think! 



f:' 



PS10O 
PB101 

PB1fl2 

PB103 

PB104 
1 



Id IC cap bfsadboa^ kit. 4.5 k 6.0 k k.36" 

10 l^-DlPipBii. 5-iAiov post, '&40 M3ld»rtes¥ 

tift [3o'i-n(s, £-.8 X 43" 

12 14 DIP cap,, like PBI01 Wkth 1,340 lie 

pninis, 7.0 K 4,6"' 

24 14-DlP cap.< 4 S-way. pttHft, 2,:350 iiB 

points, 6.0 sr 9.0" 

32 T4-OtP cap.. 1060 tcEctefless tie poinH, 

a.O k9.76" 




SI 9,95 



S39.95 
$5995 



479 



mi 



E,OGICMQWlTOR 

t>iinultdn?o-js^y ttiifi'fflV^ 
itfltic and dynamir. IO'B- 
it itBtBj of DTL. TTt,. 
HTL Lit CMOS DIP JCi. 
t*i>e4<eT alee $84.35. 



photo<;lip 

Fpr pg-dVfif-ori/KanCB-oft 
sranal traclr>9. Bi-im^ iC 
leadB up 'rom PC b'Ofl^d 

dhcii^itlng. 

PC 14 14-pir *4.50 

PCIG 16 Pin 4,Ja 



^ 




I r I >i a I 

J '■" 



I 



SOCKETS g. BUS STRIPS 

PludHPi, who^ tost, rniadify or ehpAricI wltfiout 
cords UT iv\^ti(, ^rcDp toiJB'Bier id forni. brqed 
na^dcd. 

L. HdlatQ HleJ« Term'lf 




PM/Deicripti!dn 

QTQSs So^k«t fi.5" 

QtGEfB E3U1 6.5" 

dT^VaSockut 5,3" 

QT47S Bu? 5,3" 

Cir35SS0i;h»t 4.1" 

QT35B But 4,1" 

aiteSS^iekei: 2.4" 

QT113SS«CkaT 1.fl" 

OTSS Soiikei 1.4" 

■QT'7S Socket 1.3.: 



0.2" 
&.2" 

6.0" 

3.B" 
3" 
1" 
5" 
1" 
■0" 



11$ 

34 

IS 
70 
12 
36 
24 
16 



$ 



pttcd 
bq[]rcJ 

Prioa 

12.50 
2.50 

10.00 
2.25 
B.50 
2.0iJ 
4.75 
3,7fi 
X5B 
3.d0 



7400IV» TTL 



74aQN 


$.12 


7442N 


.50 


74&7N 5.&0 


74154N 


7401 N 


.15 


7443N 


,77 


74100r>s1.Q'0 


?416SN 


7402N 


.14 


7444N 


.77 


74104N 1.20 


74166N 


7Jt03N 


.15 


744 5M 


.77 


7410SN -SO 


141 TOW 


7404 N 


.16 


7446tg 


.B3 


74107N .33 


741 7 3N 


740&N 


IS 


744 7 N 


,72 


7410914 .74 


741 74 N 


74Q6hl 


59 


744eN 


,ea 


74110N .72 


7417514 


74C17N 


.2& 


74501V 


.14 


741 ITN 1.20 


741 7eN 


74Q8W 


ie 


74S1N 


.14 


741 16N 2.00 


74177N 


74Ch9N 


.30 


74^3N 


.14 


7412tN .35 


7417aN 


741 QhJ 


.16 


7454N 


.14 


741 22N .33 


74179N 


741 IN 


.24 


74B9M 


.20 


74t23N -70 


7418CM 


7412N 


.33 


74fiON 


.14 


74125N .47 


74181 N 


7413N 


.44 


74 7 ON 


2fi 


74136N -53 


74ia2M 


7414N 


.55 


74721SI 


,26 


74128hl .»4 


74ie4M 


741SN 


.30 


7473N 


.1^7 


74132tsl 1,10 


74ie5M 


741 ^N 


.33 


7474N 


.32 


?4t36Jy .95 


74iaaN 


741BN 


.25 


7475N 


.50 


741 41 N 1,20 


74igON 


7420N 


.13 


747eN 


32 


741 45 N .91 


741B1N 


74ilN 


.39 


74eON 


.49 


741 47N 2,40 


74192N: 


7422N 


.50 


74B1 N 


1.30 


74148 r^2. 00 


741 &3N 


7423N 


J37 


74&2W 


.&S 


741 SON- 1.00 


74194IS! 


7425tsf 


.23 


743314 


70 


7415 1W .BO 


74195N 


74261V 


.23 


74S4N 


3.00 


?41S?.N 1.40 


74t9eN 


742 7 N 


.55 


74B5N 


,90 


741 53N .79 


74197N 


743eN 


.33 


74&6N 


.34 


741S4N 1.40 


74198N 


7430N 


.20 


?4B9hl 


2.30 


741 55N .97 


74199M 


74S3N 


.124 


74dOM 


.43 


741E6N .95 


7 420 CUM 


74q3N 


.36 


749 TW 


.7B 


74157N 74 


74221N 


74137N 


29 


7492K 


.49 


741 B8N 1 60 


742S)N 


.74 saw 


.29 


74Q3N 


.49 


741SDN 1.24 


7427 BW 


74ayM 


.38 


7494N 


.72 


741 61 N ,99 


74a?9M 


744DIV 


.15 


740 5 N 


.80 


741S2M1.25 


74293N 


7441N 


.a? 


7496 rs( 


.70 


74l63hl .99 


74;i9aM 



HtOK SPEED TTL 



74H0ON 
74H01I^ 
74H04N 
74HQSlVi 
74HCiaN 
74H10M 
74H11^J 



74L0DiM 
74L02N 
74L03M 
74L04M 



74LSOO 
741.S01 
74LS02 

74LS03 
74LS04 
74UGC1& 
74LEaS 
74L$Q<9 
74LS10 
74LS11 
74LS15 
74LS20 
7aL£2l 

74LS22 
74US2 7 
74LS30 
74LSS2 
74LS38 
74LSS1 



t4&00 
74301 
74S0S 

74S03 
74S04 
74S05 
74509 
74S09 
7431D 
74S11 
74S1S 
74520 
74Sai 
74330 

93QOPC 
9301 fC 

9304PC 
9306PC 
930fiPC 
3309PC 
931 OPC 
9311 PC 
931 ^PC 
931 4PC 
I 93T6PC 



.33 74Ha0lS3 

.25 74H21N 

.33 74M23N 

.33 74H30IN 

40 74H40M 

.33 74H5aN 
74HeiN 

LOW 



.33 



.33 74HE2M 

.33 74H53N 

.33 74H&4N 

.33 74H55N 

,36 74HGON 

.36 74M7 1N 

36 74H72N 

POWER TTL 



1.10 

1,10 

1 29 

S.OS 

1.34 

1,25 

.94 

.90 

.SO 

90 

S.SO 

.80 

2.39 

,70 

1.64 

2.20 

4.7-5 

1.20 

1.20 

,96 

.95 

1.10 

.74 

99 

.78 

1.60 

1.6Q 

5, GO 

1,S0 

1.75 

2.45 

.94 

1.0D 

1,9a 



36 74H73W ,fl0 

36 74M74N .«0 

36 74H7eN -75 

36 74H102N .75 

36 74H103N .90 

76 74H106N ,9S 
.75 



H=TOS 

LM1ID5H 
LM lOfiH 
LM114H 
LM300H 
LW300M 
LM301AH 
LM301,^M 
LM301AM 
LM3aiM 
U(M302M 
LM302M 
L}VI304H 
LM30aH 
LM305AH 
LMSOSN 
LMSOeN 
LM307M 
LM3a7M 
LM308H 
LM30SAW 
LM30BD 
LM30AW\ 
LMaOSH 
LM309K 
LM310H 
_LM310W 



.24 74L 1 ON 

.24 74L20N 

.39 741..43N 
.33 



.24 74L5irM 

-33 74L73N 

1.33 74L74W 

74LS0O 



1 -a IDup 

.3S 35 
.5Q .49 

.39 .3B 



.39 

.4S 
.45 



.3B 
.44 

.44 



39 .36 

.45 .44 



.39 
.42 



.3S 
.41 



S7 ,SS 

.39 .39 

.56 .55 

.60 .59 

.45 .44 

.39 .3S 

.45 .44 

.53 .52 

39 .38 



74LS34 

74LS6& 

74L573 

74LS74 

74LS76 

74LS7i 

74USSS 

74LS107 

74lvS109 

74L5112 

74L3113 

74LS114 

74LS123 

74LS13S 

74LS13g 

74LS151 

74 LSI 53 

74USt57 

74LS15a 



1-S ID up 

.55 .54 



.39 

.55 

,es 

.65 

.92 
2.19 2 

.66 

.«5 

.66 

.92 

,92 
1.30 1 
1.B9 1 
2.00 1 
1.5S 
1.89 



.38 

,64 
.64 
.64 

.91 
.10 
,64 
.64 
.64 
.90 
90 
.29 
.95 
.95 
1.50 
1.65 



,B5 



50 
60 



.34 74L90N 

.43 74L93N 
90 74L9SW 



74LS160 

74LS161 

74LS162 

74LS1&3 

74LS170 

74|,SlT4 

7 4 LSI 75 

74LS131 

74 LSI 90 

74LS191 

74LS195 

74L3194 

74LS196 

74L&25I 

74LSJS3 

74LS257 

74L£25fl 

74LS^60 



1.62 
1.51 
1.62 



1-9 lOup 


3.00 S,9D 


3,00 2.90 


2.25 2.20 


2 25 2.20 


5.90 5.70 


2,20 2.15 


2.40 2.35 


3.69 3.65 


2.^5 2.fiO 


2,8S 2.80 


2.SS 2.90 


2.25 2.2Q 


2.23 2 20 


2. OS 2 00 


2.42 2 40 


1.89 1.95 


2,06 2.00 


50 44 



SCHOTTKY TTL 



.44 

.76 
.60 
.75 
-5S 
.76 
BO 
.76 
.55 

.es 

.76 
.B5 

.76 
.60 

St,00 
I.ZO 
1.&Q 
6.90 
a. 50 
1.60 
1.50 
2.30 
1.20 
1.30 
1.50 



74332 

74S40 

?4£50 

74S61 

74S60 

74S54 

743G5 

74S74 

74976 

74379 

74665 

74S96 

74S112 



BO 
65 

.76 
.90 
BO 
SO 

80 
.90 
1.16 
1.16 
6.10 
2-50 
1.00 



74S1 13 
74S114 
74S133 
74$ 138 
T4B139 
745140 
74S151 
74B153 
746167 
74515$ 
74S160 
746161 
74S172 



1.50 

1.30 
.80 
2.20 
2.20 
.30 
2.20 
3.40 
2.40 
2.00 
3.90 
4.70 
6.00 



9300 SERIES 



931 SPC 
9321PC 
932 2PC 
932 4PC 
932 BPC 
9334PC 
933aPC 
9340PC 
9341 PC 
9342PC 
9360PC: 



3,30 
1.2d 
1.30 
2.00 
2.50 
2.96 
3.30 
5.00 
4.10 
1,15 
1.75 



9366PC 

93L00 

aSLOl 

93L0& 
33L09 
93U10 
93Ln 
93L12 
93 LI 4 
93t16 
93Lie 



1.75 
ISO 
1,60 
3.20 
1 SO 
2.80 
4.20 
1.80 
1-70 
3.20 
3,50 



74S174 

74S175 

74S1*S1 

74S183 

745194 

74S195 

745 251 

74S353" 

74S257 

74S2Sa 

74S260 

74S280 

74S289 



93L18 

93i_21 

93L22 

93L24 

93L28 

93L34 

93U38 

93L40 

93L41 

93L60 

93 Las 



3.30 
2.9Q 
6.00 
40 
30 
30 
20 
40 
40 
40 
20 
70 
,00 



350 
1.60 
1.80 

3.70 

4.00 
4.20 

6- BO 
6.50 
3.00 
2.70 



3.90 

4.90 

3.00 

1-20 

1-20 

.50 

.90 

1.10 

.95 

1-30 

1,40 

1.20 

.36 

1.06 

1.00 

95 

.60 

1.50 

.65 

00 

25 

00 

7S 



LINEAR IC's 



1.50 
ISO 



LM311H 

LM3110 

LM311M: 

LM312N 

LM31BH 

LIVi3l9M 

LM324N 

I.M331M 

LM336K 

LM339fM 

LM320-5K 

LM320-5T 

LM320-12K: 

LM320-12T 

LM34D-5K 

(_M340-6K 

LM340-3K 

LM340-12K 

LM34D-15P; 

LM3404e*t 

LM34024K 

L.M555CM 

LM56GCM 

LIW1S67CM 

Liyi709CH 

Lf^709CM 



20 
90 
75 
75 
50 
40 
90 
25 
40 
20 
90 
.50 
90 
SO 
.60 
.00 
.60 
.60 
60 
60 
60 
70 
30 
70 
75 
75 



R DIP K=TO-3 

LM710CH .90 
LMTIOCN .90 
LIVI711CH .90 
LM711CW .90 
LiVl7t6CH 3.50 
LM715CD 4.8,0 
LM723CH .60 
LM723CM ,66 
LM725CH 1.50 
LM7S6CO 5.00 
LM733CH 1.40 
LM733CD 3.50 
LM733CM 1,30 
LM741CH .40 
LM741CD 1.25 
LM7411CM .39 
LM747CH .75 
LM747CN .90 
LM74BCM .56 
LM777CH 2.15 
LM777CM 2.tO 
LMSCWaCN .95 
LM3064CN1.60 
SG45D1T 2.40 
SG4501M 2,40 
LMSOOOfc 7.50 



CMOS 



P/N 

40D0AE 
4001 A E 

4D02Ae 
4QQ4AE 
4D06Ad 

400 7AE 
400€.AE 
4009 A E 
4010A£ 
401 1AE 
4012AE 
4D13AE 

401 4AE 
40l5Ae 
401 6AE 
4017AE 
401 BAE 
4019AE 

402 OAE 
402 lAE 
402 2AE 
4023AE 
4 024 A E 
40a5AS 



V9 lOup 

.24 .23 

-24 .22 

.24 .22 

4.00 3,99 

1.30 1.20 

.24 .23 

1.79 1,65 



.59 
.50 
.24 

.24 
.46 



.51 
,49 
.23 
.22 

.40 



1.45 1.34 
1.24 1.23 

.50 .49 
1.15 1.07 
1 .24 1 ,23 

.50 



1,45 

1.39 

1.06 

.24 

.89 

.24 



.49 
.34 
.25 
.fl9 
.22 
.80 
,23 



402 7AE 
4029 A E 

4 039 A E 
4030AE 

4033Ae 
403 5AE 
4040 A € 
4041 A E 
4042 A E 
404 3AE 
4044A E 
4047 A 5 
4Q4BAE 
4049 A E 
4050AE 
4061 A E 
4052Ae 
4053AE 
4055AE 
4066AE 
4063 A E 
4 065 A E 
4D68AE 
4Q69AE 



1-9 lOup 

.55 .53 

.96 .88 

1 25 1.23 

.44 .40 

2.00 1 .94 

1.25 1.14 



1.59 

1.82 

.73 

.85 

.80 



1.50 
1.7S 

.75 
.80 

.75 



Z.7& 2.70 
1.43 1,42 
,6B .53 
5S .63 
1 ,49 1 .48 
1.49 1.4S 

1.49 1.48 
1.96 1.94 
1.93 1.96 

2.50 2.49 
1.10 1.09 

.50 ,40 
.44 .43 



P/N 

407 DAE 
4071 AE 
407 2AE 
407 aAE 
407 5AE 
4076AE 
407 7AE 
4076 A £ 
4081AE 
40e2AE 
4095AE 
4098 A E 
4099AE 
4507AE 
4509AS 
4510AE 
451 4Ae 
..45f6AE 
4516AE 
451SAE 
4520A6 
452BAE 
456SAfi 
4901 A E 
4911AE 



1-9 IQup 

,60 .69 



.35 

.34 

36 

.3S 



.33 

.31 
,35 

,36 



1.24 1,33 



,70 
39 

.25 
,34 



.69 
.36 
.23 
,31 



3.00 1.99 
1.30 1.29 

2-90 2,89 
.60 ,55 
2.20 Z,l9 
1.45 1.44 
5,00 4,99 
6.00 4,99 
1.75 1,74 
,99 
.98 



1.23 
1.28 
1.59 1.45 
2.05 1,69 



.43 

.43 



.36 
,35 



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£e.40 
9.90 
15.70 
24.90 
34.90 



1-AMP RECTIFIERS 



IN 4001 
1 N4002 
1 N4003 

1N:4004 
1N4005 
1N4D06 
IN 4007 



10 

1,00 
1.10 

i.2d 

1.30 
1.40 
1.50 
1,60 



100 
7,00 

8.00 
9.00 
10,00 
11. &0 
12,00 
13,00 



1000 

50.00 

70,00 

30,00 

90.00 

100,00 

110 00 

120.00 



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eU20S 

BU206 

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■0U2Oe 
aU209 



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6A 

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160OV 
170Oy 
1300V 
1 50O V 

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$4.14 
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6,94 
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6.93 
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32 
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140 
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100 
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70 
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35 
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APS15-3 

Al'S34a,2 

APS2e-2 



$39.60 each 



APS 5- to 

AP$i3-7 
APSTfi^ 
APS 24-6 
APS 26 -4 



Output 



Vdc 



5 

12 
IS 
24 



6 
13 
IB 
24 
28 



5 

12 
15 
24 
3B 



Amps 



3,0 
1.6 

1-5 
1.0 
Q.8 



6 

-4 

3 

2.2 

2 



1-4 



!^39.95 



10 
7 

e 

5 
4 



^4B.45 



S73,25 



Sup 



MICROPROCESSORS and LS 1 



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P1101A1 

P2103^1 

91L02 

91L03'1 

&0^0A 



19 

3.20 
3.60 
3.90 
3.90 
3.»0 



10 up 

2,10 
3.30 
3.00 
3.20 
3.20 
33,50 



1702 
PS 101 

PBtD1'3 
4*9 1 02 
PS 102-2 

P8in-2 

9103PC 



17.00 

5. SO 
6,00 
4,00 
4.00 
6.60 
6.00 
4.00 



$26.60 



$^46. 05 



CO]VlPUTER 
1MTERFACE 



PM9630M 

D!VlSe20AN 

PMB63QN 

DM963 IN 

DM8332 M 

|^aT2Sa 

9600PC 

geoipc 

9 6 03 PC 
9&14PC 
961 SPC 
96 1 6PC 
961 ?PC 
962 OPC 
9531 PC 

75107 
75t07BN 
75l0eBN 
751 09N 
75110StJ 
75115TSI 
75 1 38N 
751 SON 
76154I\J- 
75208N 
7B334M 
75450N 
75451N 
75452N 
7S4B3W 



2.40 
6,90 
2.40 

5.20 
6.00 
4.40 
1,30 
1.20 
1.95 
2.30 
2.40 
5.00 
3.50 
4.00 
4.00 



BIPOLAR 
IVtEMORY 

C3101 6.50 

pgioi 4.90 

C3101A 7.30 

P3101A 5.80 

IM5S0lCEiE 7:30 

I MS 501 CPE 5.S0 

MM5&60O 7.30 

MM5560N 5.90 

CIM6699M 5.60 

93403 PC 6,80 



M OS-US I 



2. 
3. 
2- 



.60 
.30 

-20 
2.20 
2.26 
2.95 
3.10 
4,10 
2.70 
2, SO 
1.25 
1.00 
1.00 
1.QO 



7520 SERIES 

SENSE AMPS 

7520M 4.00 

763irJ 2.00 

7522N 4.35 



7B23N 
7524N 
752 5N 



1. 

3, 
4. 



75 
00 
50 



1024-B 
N-ChJTinfli 

C2102 

P-2 1 02 

C2102-1 

P2102-1 

C2 102-2 

P-2 102-2 

P.2102A 

P-2 102 A -2 

P 21D2A 4 

2601-1 

2601-31 

26028 

2602^18 

2602 2G 

MK4102P 

7S52-1CPE 

7552 5CPe 

TM54033JL 

TMS4033NIL 

TMS4034JL 

TrVIS4034NL 

TIVIS403SJI. 

TWS4035NL 



fT 
RAM 

5.00 
2,86 

6.00 
3.90 
6.00 
3.00 

a. 00 

9.50 
6.00 
4.00 

11.40 
3.50 
4.40 
4.00 

11.40 
6.00 
6.00 
9,00 
4.30 
3.00 
4,20 
9.00 
4.20 



TWO'PHASE 

MOS CLOCK 

DflfVEn 

MHQD2eCN 5. BO 

DECODED 

REAO/WFIITE 

RAM 

P1103 5,&0 

Z534V Recirculating 

512 Bit Dyna-mk 

Shift H agister 

1-24 3,40 

25 up 2.30 



MM 



MM404H 
MM405H 
MM40^H 
MM407H 
MIVI451 H 
(VIM454F 
^MSOOH 
MhA506H 
M1^507H 
JV1M550H 
MM551H 
MMS56H 



12,00 

23,00 
B.50 
6.60 

11.40 

19,00 
2.00 
3.20 
3.20 

' 6.90 
5,&0 
6.60 



1402 AN 


3,90 


1403 AH 


400 


l403At^ 


3,90 


1404 AH 


4,50 


14 04 AN 


2,90 


14a^A 


4,00 


1406 


6.40 


1407 


a.4i) 


1506 


3.00 


1507 


3.00 


1602 


33,00 


P21D1 


5.00 


P2101-1 


5, BO 


P2101 3 


4. BO 


P2111 


E.eo 


^2111-1 


6.00 


P2111.3 


6.90 


Pai12 


5,00 


P2T12^3^ 


5.90 


P2401 


9.90 


P2405 


9.70 


2E0SK 


3.30 


2512K 


4,00 


3S2IV 


2,50 


2525 V 


3.50 


2533 V 


7,90 


2a03PC 


4.00 


2go4Fc 


4.00 


28q7PC 


2.70 


2809 PC 


4.00 


TMS3114J 


9.40 


TMS3130JC 


7.0D 


TIV1S3120NC 


6.00 


TME3133tsrC 


7.50 


3341AOC 


s.oo 


3341 A PC 


7.00 


3347a c 


5.90 


334 7FC 


4,60 


4102 


4.95 


7552 


4.96 


7562.1 


5.40 


7552-2 


5.60 


MM40SBD 


t3.00 


MM4B56H 


970 


MIVI4Q57D 


13,00 


MM6035N. 


20.00 


MM5026N 


20.00 


MMS027N 


20.00 


MM5055N 


5.50 


MM5056N 


5.60 


MMS057N 


6,50 


MwrsOsSN 


5.50 



SOLDERTINDIP 



IC SOCKETS 
WIRE -WRAP GOLD 



PIN 

B 
14 
16 

24 
2d 

36 
40 



1-24 

.21 
.25 
.2S 

.67 

.6S 

1.09 

1.24 



2S 

.19 
,22 
35 
.61 
.90 
.98 
,12 



100 

.17 

.20 
23 
.55 
.72 
.83 
-93 



PIM 1-24 



14 
16 



A5 
.64 



25 

41 
,49 



10Q 
,37 



TEFLOWTO-5 



SOLDER ' GOLD DIP 



3 Piw 
4PfcN 
6 PIJ^ 
5 P3N 
ID PiN 



.56 EA 

.05 EA 

.90 EA 

IIOEA 

1.40 E A 



14 

16 



.34 
.37 



.31 
,34 



.28 
,31 



.12r' diB. 



209 RED $.36 

309 YELLOW 35 

209 GREEN 35 



LOW PROFILE 




di 



226 
326 
326 

226 



.200 

RED 

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ORANGE 



FH. 



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LEDs 
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216 RED $.35 

216 YELLOW 30 
216 GREEN 30 



.200" difi. 




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5063 



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DL33 


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DL701 
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19 

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3.00 
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6.00 

4. DO 
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2.25 
2,35 
2.50 
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220 YELLOW .30 

220 Gfteew .30 



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P.O. Box 28271 

St. Louis, MO 63132 



147 



Dockef 20686 



Before the 

Federal Com muni cations Commission 

Washington, D,C, 2CS54 



In the Matter of 



Deregulation of Part 97 of the Commission's Rules concerning portable and 
mobile operation of stations licensed in the Amateur Radfo Servioe 

DOCKET NO. 20686 

NOTICE OF PROPOSED 
RULEMAKING 

Adopted; January 14, 1976; 
Released: January 27, 1976 

By the Commission: 
Commissioner Lee absent- 

1. In this Notice of Proposed Rulemaking the Commission proposes to 
simplify greatly the procedures involved in operating g station licensed in the 
Amateur Radio Service at a portable or mobile location. We propose to deEete 
those sections of Part 97 of the Commission's Rules requiring that licensees 
operating their stations portable or mobile identify their transmissions as 
originating from a portable or mobile location. Section 97.31 3, ooncernlng the 
station identification required of stations operated in the Unfted States by 
aliens pursuant to international reciprocal agreements, would not be affected 
by the amendments proposed herein, 

2. By way of background, an amateur licensee is presently permitted by 
Section 97.95(a) of the Rules to operate his station away from the permanent 
station location artywhere in the United States, its territories, or possessions as 
a portable or mobite station. Under Section 97.95(bJ a ticsnsee may, with 
certain restrictions, operate his station as a portable or mobile station outside 
the limits of the United States, its territorfes, and possessions. Sections 
97.95(a)(3) and 97.95(b)(3) require that advance notice of such portable or 
mobile operation be given the Commission, pursuant to the provisions of 
SectEon 97.97, which specifies the content of the required notice, and states, 
further, that such notice need be furnished only if the contemplated portable 
or mobile operation is or is likely to exceed 15 day*- Finally, Sections 07-87 
(b) and (c) provide that the transmissions of stations being operated at portable 
or mobile locations be identified as such. 

3. We believe those sections of the Rules cited in the preceding paragraph to 
foe superfluous. Such requirements have never been shown to be of use to the 
Commission in its raguiatory program, and while amateur licensees would in 



the future, as now, be afforded the option of operating their stations at 
portable and mobile locations, we perceive no purpose to be served in requiring 
advance notice to be given the Commission or in requiring that transmissions of 
stations being operated at portable or mobile locations be identified as such. 
We would stress, however, that in eliminating these requirements we would not 
be prohibiting those licensees wishing to do so from continuing to identify 
their portable and mobile transmissions in the traditional manner. We would 
simply no longer require it. 

4. In proposing that the portable operation station identification become 
optional, we recognize tlie probable impact on certain amateur operating 
practices and operating award programs neither regulated nor sponsored by the 
Commission. For instance, under the proposed rules, the control operator of a 
station in portable operation at a location outside its fixed operation call sign 
area I§97.51|b)] would no longer be in violation of the Commission's Rules 
should he choose not to include the portable designator when identifying the 
station. In these instances, listeners would not be able to determine from the 
identification that the station was located outside the fisted operation call area. 
Call areas would, in a de facto sense, be partially eliminated. For this reason, 
we particularly wish to receive comments on the issue of whether those 
amateur operators who would otherwise not elect to Identify their stations as 
being in portable operation should be inconvenienced in order to eliminate any 
impact upon ongoing amateur practices and programs. While adoption of this 
proposal might ultimately cause a substantial dilution of the significance of 
amateur call sign areas, it would provide the Commission with important 
indicia of the extent to which the Service is capable of self-regulation and the 
extent to which our deregulatory program is likely to be successful. 

5. For the reasons cited heretofore we therefore propose to delete in their 
entirety Sections 97.87 (b) and (c), 97.95 (a)(3) and {b)(3), and 97.97 of the 
Cornmission's Rules. The remaining sections of Section 97. S7 would be 
redesignated to reflect the deletions, 

6. The proposed amendments to the Rules, as set forth in the Appendix, are 
Issued pursuant to the authority contained in Sections 4(i} and 303 of the 
Communications Act of 1934, as amended. 

7. Pursuant to applicable procedures set forth in Section 1,415 of the 
CoiTvrnlssion's Rules, interested persons are invited to file comments on or 
before February 27, 1976*, and reply comments on or before March 8, 1976. 
All relevant and timely comments and reply comments will be considered by 
the Commission before final action is taken in this proceeding. In reaching its 
decision in this proceeding the Commission may also take into account other 
relevant information before it, in addition to the specific comments invited by 
this Motice. 

8. In accordance with the provisions of Section 1.419 of the Comm is ion's 
Rules, an original and eleven copies of all srtatements, briefs, or comments shall 
be furnished to the Commission. Responses will be available for public 
inspection during regular business hours in the Commission's Public Reference 
Room at Its headquarters, T919 '*W* Street, N.W„ Washington, D.C. 20654. 

FEDERAL COMMUNICATtONSCOJVlMISSION 

Vincent J. Mull ins 
Secretary 

*Thls Notice was received too fate for induslon in the February, Mardi and 
April issues. 



Please be advised that we have the 
unique situation of having recovered a 
Untmetrics Ultracom 25 with no 
obvious ID or serial no. 

Would you please change your lost 
column in 73 to include "found"? 
Request that interested people con- 
tact David M. Stoner K8LMB, 619 
Doepke Lane, Cincinnati OH 45231, 

Keep up the good work with 73 — I 
love it, 

David M, Stoner 
Cincinnati OH 

HIJACKED: RF Comm. Inc. RF 403 
two meter transceiver, s/n unknown. 4 
Chan. 80 Watts approx 4"h x 12"w x 
12"d. Set up for MARS freQuencias, 
34-94 and possibly other amateur 
frequencies. Color is black. Please 
notify F8I or Wallace Moore 
WB0AWH, 12053 W. Virginia Ave., 
Lakcwood CO 80223, phone: (303) 
986-3909. 



Tracking the HAMBURGLAR 



KIDNAPPED: ICOM IC230 two 
meter transceiver, s/n 2403009. Rig 
was taken without the mike on 
December 9, 1975 in Cleveland, Ohio* 
Contact Ferd H. Nye, Jr, WA8MXT, 
31497 Hilliard Blvd., Westlake OH 
44145. 

ROBBED; SB- 144 two meter trans- 
ceiver, s/n 620962 with ^'W&PJ" sten- 
ciled on the set. The wires were cut 
and the set with microphone was 
removed. It was equipped with 34-94; 
94-94; 16 76; 22-82; and 52-52. It 
also had county and one city receiving 
police frequency. Taken on January 
17, 1976, Please contact Dr. Shailer 
Peterson W5PJ/K4HL, 5511 Keystone 
Drive, San Antonio TX 78229, phone: 
(512)684^0449. 



ABDUCTED: Heathkit HW 202 two 
meter transceiver, s/n 07429. Taken 
from auto of Dick Cullen WB0AGT. 
Mike has broken switch bar, "Stolen 
from WB0AGT SSN 410 66-8452" 
engraved on back. Has home brew 
synthesizer installed on top of set in 
mini box approx, same %\ze as HW202 
and is painted black. Has 2 RG-174 
interconnect cables. Xtals installed: 
37 97, 34-94, 28-88, 07-67 and 52-52. 
Please notify Dick Culten WB0AGT, 
1515 Newcastle St., Colorado Springs 
CO 80907, phone: {303) 598-1 849. 



LIFTED: HR-2 Regency two meter 
transceiver, s/n 04 02689. Xtals in- 
stalled: 34-94, 94-94, 16-76. Please 

notify Dick Sucher WA0ZLY, 3410 



N. Prospect Sl, Colorado Springs CO 
80907, phone: (303) 473-4186. 

LOOTED: Unimetric Co,, Ultra Com 
25 — 12 chan. two meter FM trans- 
ceiver, s/n 0S0'T14. Taken from car in 
Akron, Ohio on September 12, 1975. 
Contact Herman Freeder W8VQI, 944 
Jason Avenue, Akron OH 44314. 

RUSTLED: Heath HW- 20 2 two meter 
transceiver. Crystals instated: 34/94, 
94/94, 07/67, 16/76, 88/88. Can be 
identified by wrong size wire on PC 
board, modulation is set HOT, so 
normal use will clip out on repeaters. 
Please do not discuss this incident on 
any of the above frequencies. Stolen 
from Doc. A. L. Stigers, Golden GO 
S0401, phones (303) 237-3296. 



148 




** • 



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MN'2000 ANTENNA MATCH BOX 220.00 

W'4 WATTMETER 1 .8 TO 54MHz . . , 72,00 

WV 4 WATTMETER 20 TO 200MHz 84.00 

RCS'4 REMOTE CONTROL ANTENNA 

SWITCH T20.00 

L-4B LINEAR AMPLIFIER 895.00 

SSR-1 COMM RECEIVER ...... , 350.00 

SWAN 



700CX TRANSCEIVER , 

MB-40A TRANSCEIVER 40 MTRS 
MB^aOA TRANSCEIVER 80 MTRS 

P1215A P/S MB-40A/80A ... 

117XC AC/CONSOLE P/S 700CX , 

FP-] PHONE PATCH _,._._., 

510X OSCILLATOR 

laOOX LINEAR AMPLIFIER 



9 9- m 



V 4 lP- 



A « «■ * h 



. 649.95 
. 329.95 
. 329.95 
. . 75.95 
, 159.95 

. , 64.95 
. . 67.95 

.349.96 



SWR-1 rf WATTMETER TO 1 kW, 3.5-1 SOMHz Power 

Meter/SWR Meter, SO-239 Conneaofs . 21 .95 

WM 2000 POWER/SWR IWETER ._,.......__. 49.95 

WM-:^00 POWER/SWR METER , , , . , ,,.,,. 66.95 

45 ANTENNA ALL BAND IkW PEP. Manual switching. 

No coil swrtching , , , , 1 14.95 

742 TRI BAND 20^0-80 MTR., Electronical ly 

automatic band swttchline 500W PEP . _ . 79.^ 

COLLINS 



KWM2A TRANSCEIVER . . 
75S-3C RECEIVER ....... 

32S^3A TRANSMITTER . .. 
51 6F'2 POWER SUPPLY ., 
30b1 LINEAR AMPLIFIER 

31 2Br4 CONSOLE... 

312B-5CONSOLEA/FO 
SlSrl RECEIVER 



V I F 1^ 



f -I P » 



h « » * « 



t u 4 * i 



9 m * •¥ 



* ♦ •% 



.2.120.00 
.1,593.00 
.1,840,00 
. . 265.00 
. . 973.00 
, , 360.00 
. . 759.00 
.2,927.00 

373.00 



55G-1 PRESELECTOR 51 SI 200 Hz to 

2MN7 

SHURE 

444 SSB DESK TOP MICROPHONE with OFF-ON VOX 

svw ten or ri t ,,,«,,.,... v-^*^^,.,.^,,^^,.. mi^£^ ^v 
444TSSB DESK MICROPHONE with OFF-ON VOX 

switch or PTT, t>uift-m tTansistorfzed pre-ainp . . . 42,50 
404C HIGH IMPEDANCE MAGNETIC HAND-HELD 

MICROPHONE, for SSB. PTT. ideal for 

Atlas or SWAN 27.00 



.229.00 
. 259.00 
.239.00 
, 349 00 

. 239.00 
.119 00 
. . 49.95 



HR 2B FM 2 METER TRANSCEIVER 

HR-21 2 FM 2 METER TRANSCEIVER ....... 

HR'220 FM 220 MHz TRANSCEIVER _ . 

HR-440 FM 440 MHz TRANSCEIVER 

HR'66 FM 6 METER TRANSCEIVER . . 

AR 2 2 METER LINEAR AMPLIFIER ........ 

P-110 POWER SUPPLY 117V to 13.8 DC 5 AMP 

BRIMSTONE 

144 2 METER FM TRANSCEIVER, 25 Watt, 143.00 lo 
149.99 MHz. Oigital Dialed 5K HZ steps. No crvstals to 
buy. 142 MHz MARS coverage optional $650.00 

COWCRAR 

CST50 VHP TWO BAND TRANSCEIVER, 2 and 1!4 
Meters, Digital Frequency Synthesis 142 to 149.995 MHz 
and 220 to 225 MHz, 25 Watts $869.00 

MILLEN ^ 

92200 ANTENNfA MATCHBOX All Band 2 KW . . . 199,00 

92201 JR ANTENNA MATCHBOX AH Band 
300 Watts . 

90652 SOLID STATE GRID DIP OSCILLATOR, 
battery operated and coil }J thru 300 MHz 
supplied 

CUSHCRAFT ANTENNAS 



. .138.00 
9 volt 

..138.00 



Al47-4 146-l48MHz4ELBEAM ,_ 

A1 47-11 146-148 MHz 11 EL BEAM __.. 
A147 22 14&148MHZ 22EL BEAM ...... 

AFM-4C J. POLE 144-148MHz .._.__, 
ARX 2 RINGO RANGER 135-170MH^ . . . 
ARX-220 BINGO RANGER 220-225MHz , 
ARX 450 RINGO RANGER 435-450MHz , 

AR-6 RINGO 50-54MHZ , . 

DX-120 144MHz 20EL DX ARRAY SEAM 
A14'VPK VERT POLE STACKING KIT 

TWO T47-4 
A147 VPK VERT POLE STACKING KIT 

TWO 147-11 ,, 

CR^I RINGO CB ANTENNA . 



'4:1^ 



. . 14.50 
. . 23.96 
..68.50 
. . 52.50 
. . 26.50 
.. 26.50 
. . 2€.50 
. . 23.50 
38.00 



<■- « 4 



*■ * m 9 » 



... 19.95 



22.95 

26.50 



ANTENNA SPECIALISTS 



ASP558 TWO METER 5/8 WAVELENGTH 3de MOBILE 
ANTENNA, mag. mount iriQ, no holes to drill .... 36.50 



BARKER AND WILLIAMSON 



375 PROTAX ANTENNA SWITCH with automatic 
grounding, 6 posttion rear mounted 

SO-239 connectors ,,,.*,,.,,...,.._ 1 8.50 

376 SAME AS ABOVE, B position side mounted 

Sa239 ......,, 18.50 



ATLAS 



210X 80 THRU 10MTRS 

215X160THRU 15MTRS...... 

220CS AC SPKR CONSOLE . . . - 
200PS PORTABLE AC SUPPLY . 
DMK PLUG IN MOBILE MOUNT 
MT-1 MOBILE ANTENNA 

MATCHING TRANSFORMER 

PCT20 NOISE BLANKER 

VOX ACCESSORY 

10X CRYSTAL OSCILLATOR . . 



■ «■■■'* « 



. 649.00 
. 649.0Q 
. 139.00 
. . 95.00 
..44,00 



«• * fe 4 



• 4 ■. 



>> « * 



24.00 
48.00 
45.00 
55.00 



TRADES TAKEN ON NEW EQUIPMENT. WE PAY SHIPPING VIA UPS. OR BEST WAY ON 
ALL ABOVE ADVERTISED ITEMS. SATISFACTION GUARANTEED, ALL ORDERS 
EXPERTLY HANDLED TO ASSURE SAFE ARRIVAL. WE ACCEPT MASTER CHARGE. N.C. 

RESIDENTS ADD 4% SALES TAX. PHONE BILL SLEP (704) 524-7519. 






. P.O. BOX 100, HWY. 441, DEPT. 73, OTTO, NORTH CAROLINA 28763 



150 



The Black Watch kit 



At $29.95, it's 

*pracfical-easily built by 
anyone in an evening's 
straightforward assembly. 

*conripiele-right down to 
strap and batteries. 

^guaranteed. A correctly- 
assembled watch is 
guaranteed for a year, ft 
works as soon as you put the 

batteries in. On a built watch 
we guarantee an accuracy 
with in a second a day-but 
building it yourself you may be 
able to adjust the trimmer to 
achieve an accuracy within a 
second a week. 




The Black Watch by Sinciair is Lrnique. 
Controlled by a quartz crystal . . . 
powered by two hearing aid batteries 
. . , it's also styled in the cool prestige 
Sinclair fashion: no knobs, no buttons, 
no flash . . . just touch the front of the 
case to show hours and minutes and 
nninutes and seconds in bright red 

LEDs. 

The Black Watch kit is unique, too. 

It's rational-Sinclair have reduced the 

separate components to just four 

It's simple-anybody who can use a 

soldering iron can assemble a Black Watch 

without difficulty. From opening the kit to 

wearing the watch Is a couple of hours' work. 



vfs 



€ 



V 



LEOdisptay 


Complete kit 


^ / 


$29.95! 


^^MT 


The kit contains 


iVB^^^^^ 


1. printed clrcuil board 




2. unique Sinciair-designed IG 




3. encapsulated quartz crystal 


^^v^V^ /^ Jm^i 


4. trimmer 


i T w^ / /^ri^ 


5. capacitor 


^OL-jJr ^r * .^^^F J^F 


6. LED display 


^^^r^M/^W 


7. 2-part case w th window fn 


y ^^Vb^hT J^mwK^^^j^r^ 


position 


^^^tp^^^UBt 


i. batteries 


i^fli^rV 


9. battery-clip 


X^^^^r \ 


10. black strap (black stainless- 


W^^r \ 


steeE bracelet optional extra- 


^^^ Y 


see order form) 


w\ V 


tt. full instructions for building 


* \ 


and use. 


Trimmer \ 


Aff you provide is a fine soldering 


^k Quartz cry Stat 


If on and a pair of cutters. 



^ J'j 



Batteries 



2000-transistor silicon integrated circuit 



1 
I 
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1 
I 
I 
I 
I 
I 
I 
I 
I 
I 
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Ptease send me 

^Black Watch Kits @ $29.95 

, . plus S2.50 shpg. & hndlg. 

Stainless steel bands 

@ S5.50 

NY residents please add sales tax 
t enclose my check/MO for S 



Name. 



Address 



73-5 



IMPORTANT 

PrSnl 'iQxxT name and address here 
tar ust as a shipprng labef. 
Thank ]fOu. 



Name 



Address. 



FREE 10 DAY TRIAL 

If you decide not lo keep vc>ur 
Black Watch Kit, return it un- 
damaged with in 10 dayii for a full 
refund on the kit. 



Mail to: 



^ip. 




indair^ 



SINCLAIR RADIONICS 

Suite 400 

8S8 7^h Avenue 

New York NV 10019 



1 
I 



NOW UNDER 

NEW 
MANAGEMENT 



SUPER - SUPER - SURPLUS OUR 1st AD IIS OVER 2 YEARS 
OUR CATALOG NOW BIGGER & BETTER THAN EVER„„SEE BELOW 



CHOMERICS PHONE TOUCH PAD - 
New packaged surpluf key^^B^^ ^ 
Chomertcs. Use with our AY-S-d1Q0 t«l«- 
phone dialer chip for complete Touch-Torw 
dialer phoning. Size: 2%x3x^"thick. Ustfut 
for Gl and Motorola Dialer ch^pi. Quftfirty 
limited. Priced for quick sale: S4 55 Mch^ 
10 and up &4.2& each, 50 and up $2^8 udh, 
100 and up $3.00 each. 

Sh, Wt. 4 oz, 5M 100349 $4.50 

3 for $13.00 5MI00349 $13 00/3 



I 




GET A COPY 


OF OUR SUPER 


CATALOG !!!! 


BARGAINS*'„, 





KLH SPEAKER ENCLOSURES • • * 
ANOTHER SPECIAL PURCHASE 

The$e Model 23 enclosures were designed for i 
2 way system 12*' Woofer arwJ 2" Tweeter 
(easily modified by adding holes for other 
tpeakersh in a handsome real Walnut wood 
CdbineL We have a super deal on these fine 
cabinets less speakers and grill cloth. We 
supply two (21 cabinets, less speakers, for 
$37,50. which is a steal for these super cabi- 
nets. You supply your own speakers and 
SAVE REAL MONEY! These sell with speak- 
ers for S299,00 a pair. . . 
Sh. Wt, 42 Lbs ea. 5Z00428 $25.00 «■ 

2 for S37.50 5Z00428 $37.50/2 




LOUDSPEAKER COMPONENT SPECIAL 

We have made an excellent purch»« of 
an excess inventory of a local manufacturer's 
speai^er systems, although we are not allowed 
to mention the mfr's name, the specs should 
make it self-evident* The woofer it a 12" 
free-edge (acoustic suspension^ unit, with 2" 
voice coil and a No. 2 magnet* The mid- 
range is a 5" sealed back speaker and 3>&^ 
flare dome tweeter for best high frequeficy 
dispersion. Crossover between woofer and 
mid-range is by an R>L^ network, while 
high frequency crossover is by an B-C rMt— 
work. Balance controls are provided for both 
mid -range and tweeter * Plans for a suitable 
enclosure are provided. The level controls 
provide frequency response to surt room 
acoustics, with realism that wilt delight even 
the most critical Nstener. Response: 25 to 
20 K -*- Hz. Power: 6S watts RMS. ImiM* 
dance: 8 ohms * 

Sh. Wt. 12 Lbs* LSCS $47.S0 

2 for $85.00 LSCS $8S.00/2 



DATA MANAGEMENT STATION 

SYSTEM 21 

We have located a few VIATRON 

SYSTEM 21 COMPUTERS . . . 
$669.50 

< 

m 

O 

O 
u 




90% Material in 
stock & shipped 
in 24 Hours*..*. 



A typical System 21 configuration includes 
a MicroproesMOr^ two Tape Channels, a Key- 
board, two Data Channels, and a Video Dis- 
play. Centre! to the System 21 structure is 
tfte Microprocesor which contains hard-wired 
microprograms that perform a fixed set of log- 
ical oixeretioni. The hard- wired microprograms 
in the Microprocessor accomplish the same 
functions as a general-purpose computer oper- 
ating system or assembler. Because the micro- 
programs are hard -wired; however, there is no 
need for extensive programming* 

The Microprooessor has four Input/ootput 
channels, two Tape Channels and two Data 
Channels. The Tape Chanrtels are devoted to 
either VIATAPE Recorders or Computer Tape 
Recorders, one recorder per channel. The two 
Data Channels can communk:ate with optional 
Input/output devices. They can be connected, 
for example, to a Model 6001 C^rd Reader/ 
Puoch Adapter for reading and punch ir^ cards, 
or to a Model 6002 Printing Robot for pro- 
vkdtng hard copy. The Data Channels can also 
be interfaced with a Model 6003« 6004^ or 
6005 Communication Adapter for providing a 
link with another System 21 Data Management 
Station, a computer^ or virtue My any other de- 
vice capable of US ASCI I interface. The Key- 
board has its own Channel dedicated to pro- 
viding data input and control to the Micro- 
processor . 

These systems are sent checked out and are in 
running condition. At thts time we have only 
25 System ZVs, 



SYSTEM 21 



S669,50 



ML^E - MUSIC COMPUTER COMPOSER 




This compact digital computer uses the 
latest electronic technology to compose and 
create your own synthesized electronic music, 
rt^s ahead of its tirnel Complete new packaged 
system with its own ir^structifjn booklet. Let 
price was $347.50 , , . Yours for only $139,501 
Ouanity is limited. An outstanding, unique 
experience for the buyer. A close out bargain. 




'#. 



Sh. Wt 15 Lbs. 



MUSE 



$139.60 



OSHA" TRUCK BACK-UP 

ALARM 

Yalptng noiM tCHJrc«/bftek-up alerm for fork 
trucks or whattwf. Un\m contain a water- 
proof ipefrker, electrontcs and driver circuits 
to yelp- Quanity is limited. This sf stem orig- 
inally cofi $49.S0 - youri for a fraction of that 
price. Includes bade -up alarm switch. For 
12 or -24 volt' epplications istate choice K 
Sh. Wt. 10 Lbi. SZIMMSI $19.50 

4 for $60,00 5Z00451 $60.00/4 

****Sanie as above but with weether proof 
horn for 12 or 24 volts (state choice) p 
Sh. Wt. 10 Lbs. 5Z00452 $19,75 

4 for $60.00 5Z00452 $6000/4 

24 Volt Xformer, 5 Amp. .S4.00, $15.00/5 

1103- 1024 Bit RAM $15.00/10^2,00 ea. 

MAGNUS 3 OCTAVE K£VeOAflD^10,00 

11SV Alarm Horn 51.50 ea..$S.00/4 

Fly Back XforTner..New with datmL....$ 1.00/6 

2 Amp Bridge... ,400P IV, .S,75 ea..S5. 00/10 

6 Amp Bridge.„.2OOPlV.,.„.„$1,50 ea^5.00/4 

NE555 Timer,../Circuits, ..$.95 ea..S5.00/6 

Key Alarm Switch... Hudson" . <$2.00 

Calcu, Keyboard..1x18 Matrix,. ..*..«,^«^,$2.0O 

Calcti. Keyboard. ,4x4 Matrix .,„;S1.50 

Laser C3p,180Joules. 40MFD,3KV New S24.00 
B8cL Helium-Neon Gas Laser Power Supply 
Complete less tube ,.orr 115 VAC $15.00 

3 lead Voltaae Regulator. .....14 Watts... 

5V L129 $1,25 aa., $5.00/5 
12V L130 $1.25 ea.. $5.00/5 
15V L131 ST25 ea.. $5.00/S 
Omni-Oirectional Head-Phone $2.00 
LASCR" .„..^00PIV..„„ $1.50ei„ $5.00/4 
Quad Rac...4 Amp,,400 PIV....$1.0a 
Triae..GESC240DX2l0..10A400PIV $1.50 
IR LASCR. ..200PIV..1A.$2.50J$1 0.00/5 
2N3055 NPN. Sil. 115W...,S1 2Sea.,$5.00/5 

2N2904 Pf^P^ SiU 90W $T0O«a.^ 5.00/6 

2lMSa3S NPN,TO3,100W,300V^ 1.25,55.00/5 
D44C6B,NPN, 30W,Plat> $.50ea., $1.25/3 
D4SC5B,PNP,30W, Plas. S.SOea,. $1.25/3 
FET Op, Amp. DDCIBS $2.00, $5,00/3 
SCR.s - 6ft , 200V, 10-66 $1.25/2^35,00/10 
Clock Xlormer 11V, 150 ma,,S 1-25/236.00/ 10 
"AA" NiCad Gould $1.50.J2.50/2.,$4.00/4 

Send for Test Eqpt List,. Price Right 

— ' 

Get copies of our exciting new catalogs, 
containing over 5,000 bargain items. 2 new 
exciting illustrated catalogs totalling to 48 big 
pages (11x17*' ea). An order gets you a copy 
and puts you on our mailing list for one year. 
Over 500.000 catalogs mailed each year. Get 
on our tistl 

FtEASE ADD SHIPPING COSTS TO ALL 




CHARGES WELCOMED 

Phon« w> ^4r^s to 617 i3t &TM dr fif? 532 2321. 
B4nkAffitriCWd - NtaAlBreliwp. S10.00 i?wTimtfn. No 
COO/ipieaM 

B&F ENTERPRISES 
119 FOSTER STREET 
PEABODY. MASS. 01960 
(61 7 > 531-5774 / 532-2323 




6 Digit LED Ciocic Kit-12/24hr. 




$8.50 



ea. 



QTY OF 
6 or MORE 



$6.95 



ea. 



Qty of 6 or more 
when each kit is 
purchased with a 
transformer, PC 
boardn and cabinet. 



KIT INCLUDES 

• INSTRUCTIONS 

• quality COIVIPONENTS 

• momey back guarantee 

•50 or 60 Hk OPERATION 
•12 or 24 HR OPERATION 






AH 



\^ 



cre 



# 



6 LED Readouts tFMD-70 .25 in. 

1 MM53t4 Clock Chip (24 pinj 
13 Transistors 

3 Switches 

3 Capacitors 

S Diodes 

9 Rflsjstoj's 
24 Mc^tetK pprts for IC socket 



BED^ 



"Krt 4^50 wili furnish a compf&ts set of dock components as hswd The onfy sddftfonaf items 
required are a 7-7 1 VAC transformer^ a circuit board and a cabinet^ if desif&d/' 

Printed Circuit Board for above (etched & drilled Fiberglass) $2.95 

Standard Transformer 1 1 5V AC/S V/AC 1 .50 

Molded Plug Transformer 115 VAC/8 VAC tWfth Cord) 2.50 

Pjexiglas Cabinet II Red Chassis, White Case, 

2y/'H X AVz'V^ X bYz^'D (see below) . . _ 5.95 



6 Digit LED Clock-Calendar-Alarm Kit 

• J 2/24 HR TIME • JUMBO DfG/TS (MANS4) m 2830-37 DAY 
CALENDAR m AC FAIL URE/BATTERY BACK-UP • 24 HR ALARM - 
to MiN. SNOOZE • AL TEH NATES TIME (8 SECf AND DA TE (2SECf 
OR Of SPLAYS TIME ONLY AND DATE ON DEMAND • THIS KIT 
USES THE FANTASTiC CT-7001 CHIP FOR THE PERSON THAT 
WANTS A SUPER CLOCK KIT (TOO MANY FEATURES TO LIST) > 



50/60 H^ OP 



COMPLeTE KIT, including 
Power Supply. J^iie Cord, 
Drilled PC Boards^ etc. 



X 



ORDER KtT 
#7001 B 



^ilMl^«iVl>I40] 



Kit #7001 C same as #7001 B but has different LEDs, Uses 4 DL-747 .63" 
digits a 2 MAN-7 ,3" digits for seconds. Complete kit, less case. 



$42.95 



CABINET I 



3" HIGH 
e'/i" WIDE 
S'A" DEEP 



I E3:3H I 



/ 

/ 



GREAT FOR 
CLOCK KITS. 
White PleKtgl^s Case 
Spet^ify RED or GRAY 
Pleiciglas Chassis 



CABINET II 






Jl A 



GREAT FOR 
SMALLER 
CLOCK KITS 



Chassis Serves As Bezel To Increase Contrast 
of Digital Displays. Use Gray With Any 
Color — Red With Red Displays Only tRed 
LED's with Red Chassis Brightest) djjc At „□ 



PLEXIGLAS FOR DIGITAL BEZELS 

Gray or Red Filter ^^J 

3" X 6" X 1/8'^ ApprOK. Size ***** 

4forS3.00 



NEW! 



2V2' HIGH 

47/' WIDE 

BV?^' DEEP 

(Ideal for Kit #850 above.) 

All Plexigiss Red Chassis, White Case. 

Red Chassis Serves As Be^el To Increase 

Contrast of LED Displays. Jr gr 



XTAL TIME BASE KIT for Clock- 
CBlendar-AJarm Kit $9.95 

(115 VAC or 12 VDC operation) 

Uses 100,800 KHz xtal. For #7001 Kits only, 




7-SEG 

LED 

READ 

OVTS 



CRmrnQn- 


Anode 






MAN-64 AL 


RED 


,4" 


Sl.55^a 


MAN-5 


GREEN 


.3" 


1.25 


MAN-8 


YELLOW 


,3'^^ 


1.25 


MAM-? 


RED 


,3'^ 


,95 


DL-707 


RED 


,T' 


1.25 


DL-747 


RED 


.S3'' 


2,50 


FND-510 


RED 


.6'- 


K85 


Co mm on Cathode 






HP5082-7702 


RED 


.3" 


$L25ea 


F[\JD-70 


BED 


.2B" 


.65 


FND'503 


RED 


.5" 


1.85 


DL^750 


RED 


.63' 


3,50 


DL-704 


RED 


.3' 


1,25 


DL-33IVI[VIB 


RED 


3k.T" 


,95 



1O/S15.0O 
11.00 
11.00 
8,50 
12.00 
20.00 
17.50 

10/$n.S0 

5.95 

17.50 

30.00 

12,00 

8,50 



25 AMP 

FULL WAVE BRIDGE TOO PiV 

$1,95 ea. 
3/$5.00 




DIODES 

1 N4002 , . . . 25/$l .95 

1 N4004 25/$2.25 

1 N4007 25/$2.45 

1N5400 10/$1.50 

1 JM414S 25/$1,50 

1N914 25/$1.75 



TRANSISTORS 
(some unmarked — all guaranteed) 



2N2369 (Marked) 
2N2222 (Equiv.) 
2N3394 (Marked) 
2N3646 (EquiyJ 
2N39D4 (EquivJ 
2N4249 (Marked) 
2N4403 (Equtv.J 



■ ■fHPi ■■*■ + ■ y ¥ * 

■ ■■■lil-fr-lll->%T"" 



10/$1.90 
10/$1.50 
10/S1.90 
10/$1.25 
10/$1,25 
10/$1,90 

ioysi.25 



JC SOCKETS SOLDER TAIL 

14 or 16 pin . _ 4/$1 , 25/$5. 

24 or 28 pin . , . 75<^ 8/$5. 

Transistor Sockets 12/$1. 

Power Transistor Sockets 

with assoc, hardware ....,.,.,,.,. 4/$1, 



MOLEXPINS 

1000 for $7,50 



ROCKER SWITCH 



SPDT 




47$ 1. 
1 00/$20 



4A 1 25 Vac/.5A 1 25 Vdc/1 .5A 250 Vac 



Slide Switches DPDT 



12/$1.95 



TCA 430 

4250 

741 

1458 

555 

556 

565 

566 

567 

MM5314 

CT-7001 

723 

LM309 

LM340K-12 



IC SPECIALS 

Tone Gen $1.95 

P. Op Annp ,95 

Op Amp 3/1.00 

Dual 741 .95 

Timer .65 

Dual 555 t.25 
Phase Locked Loop ,95 

Function Gen 1,50 

Tone Decoder 1*75 

Clock only 3,95 

CLKCALALM 7.95 
Regulators 

±40V. .75 

5V. 1.25 

12V. 1.75 



FACTORY PRIME .3" RED 7 SEG. LED 

MAN-7 

.95 ea., 10/$8.50, 100/$79 

(n Sealed Factory Pkg, 

COMMOM ANODE 14 PIN DIP 



SUPER BRIGHT 7-SEG, LED 

Pf^f^^ MAN-64AL ^^^ 

15MA/SEG. 
COMMON ANODE 14 PiN DIP .4" CHAR 
$1.55 ea., 10/$15, 100/$125 



HT. 



Box 219, Hollywood FL 33022 



Phone: (305) 921-2056 

BankAmericard, Master Charge 
and COD orders accepted. 



We pay ait shipping in continen tai 
USA. Orders under $16.00 add 
$hOO handUng, Flonda residents 
add 4% tax. 



153 



ou goons don ' ^ 
1 



•>^ 



' -. >' 




I insist th'st 

f torn page 100 

cotildd't I urn that down. I feel I hat 
my experience m ooming to see bow 
radio tv3S enrichett my Ule, not just 
my huiband's. might have some effect 
ort othef XYLs. It seems to me thai 
you fellows are missing the boat in 
not bringing m the nearest and dearest 
to swell the ranks. Our instruetor has 
his wife helpirig him in class as well m 
his two sons, all of whom have their 
own licenses. They made it a f^mifY 
hofobyl With all the talk about bring- 
ing in more people, why not begin at 
home? You may coumer by telling me 
that wives don't feel they can hack It 
(I know); that they are really not at 
all technically inclined (I know); that 
they don't have ali that time to yak 
(me, too), etc^ Woald you be 
Interested in an article of two from 
me? My first title could be *'Con- 
fessions of a Formerlv Ambivalcni 
XYL," followed by "Confessions of a 
Formerly Ambivalent Novice/' or 
something like that- 



you print tv 



I am as surprised as you may be to 
see this offer — I really don't need 
anythirig more to keep me busy, but t 
do fed i have something to say to 
hams and their families. Anoifier 
point I want to make is the fact that 
radio should be a very appealing 
f>obby to tone I y people. Here in Cali- 
fornia there are so many singles arid 
families wtio have little communiry 
involvement ckie to being transplanted 
or to shyness or wh^t have you. They 
would constitute a tremefKkius 
number of peopla vvhp could he 
brought into the radio family and rt 
would enrich their tives a great deal, I 
see these people in my piano classes at 
night school and my women's chorus 
sings at ho^itals, churches and clubs, 
where the same observation goes in 
spades. 1 a>uld wish that the code 
were not so absolutety necessary and 
that tiie exams were not so difficult 
(you get the idea sometimes that the 
FCC is deti berate I V trying to trick yoo 



on the answers); However, I can also 
undefstand the pride bams have In 
having mastered their skills themsefves 
and their consequent unwillingness to 
bring in others with iess skill. Some- 
times, people have to compromise 
with reality « though, if they realty 
want more members in the group. 

I personally feel that the public 
relations for ham radio is stucic in old 
concepts and r>eeds to be brought up 
to date and broadened — lots more 
people of all kinds could bertef ii from 
the friend I ine^ and increased people- 
to- people communication. This is 
undoubtedly one of the re^ons for 
the wild rush into C6. As to upgrading 
%W\\h, I feel titst an appeal to more 
specific talents could be made from 
the broader beginning base. People 
seem to love awards. Even if ttwy 
came into ham radio without code, 
tf«y could be motivated by awards 
and contests to learn it just for the 
hell of It — rather than makir>g it a 
grim requirement ^ich turns off 
quite a few. Frankly, 1 think that it 
would not be too difficult to teach 
code to anyone but for tlw psycho log- 
ical component. I vuork against this 
everyday in my ouvn classes — the 
no-conf ider>ce syndfome. Incident a My, 
I have had absolutely no background 
In radio and t avoided math and 
science classes like the plague when I 
was in school. I viras convinced that I 
v^s a moron in math and had abso- 
lutely no ability m technical things. I 
do believe that I have above-average 



imetlfgence and I em stubborn when I 
make up my mind to try something, I 
have been advised to memorize the 
handbook in order to make the 
General exam, but I prefer to try to 
understand what I am doing instead. 
It has already given me quite a lift to 
discover that I have been psyching 
myself out all my life and that I can, 
with study, learn some of these things 
which I formerly believed xfm 
province of men. \ am sure that \ 
represent many other women tn this 
respect- I am also remembering ttit 
wistfulness I have heard in the men's 
voices ori tfie radio telling my husband 
how great it is that I am joining him in 
class, how mijich they wish iheir wives 
would do the same. How about it, do 
you think we can make radio mor« 
human to XYLs? 

Froma Reiter WN6iWT 
Futterton CA 

P.S. Obviously, none of this could 
have conr>e about for me without my 
husband's strong, warm support and 
his obvious pride in my accomplish- 
ments. He bragged about my gettir>g 
the Novice license so much that I was 
sure my blushes could be heard over 
the air waves. Whether you are 
interested in any further confessions, 
thanks for listen irvg. 

Sounds great, Froma , , , fet's lee 
those articlGs and fnaybe we can gei 
ntpre XYLs mto ifie act . . . and on 
The air — Wayne, 




Glade Vallev School Radio Session 

17^^ Year July 31 - August 13, 1976 

Courses Taught: 

General Theory and Code 
Advanced Theory and Code 
Amateur Extra Theory and Code 

UPGRADE YOUR HAM TICKET 

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12 DIGIT READOUTS — 11.75 

Mfg. by NationaL Electronics. 8lg .40 In. char. slia. Gas discharge lype, for 
use In desk \op calculators, frequency coontefBt clocks, etc. #NDP 1253-12. 
OrglneJIyccfita calculator mfg. SIB.TToa. in quantity, S.D. Price SI 75 0a. 

HIGH V. TRANSFORMER lor abo^ r«ddul. hlmery 11 TV, two secondarlesT 
^ VAC 500 MA 175 VAC 100 MA. $1.25 ee. 



2102 1K RAM'S - 8 FOR $12.95 

We bought a load on a super 



New units 

dealt hence this fantastic price. 

Units tested for 500NS Speed. 



INTEL 1702A 2K ERASEABLE PROM'S $6.95 

We telt it l^ke it is. We could have said these were 
factory new. bul here is the straight scoop. We bought 
a load of new computer gear that cor^tained a quantity 
of 1?02A's in sockets We carefully removed the parts, 
verihed their quality, and are offering them on one heck 
of a deaL First come, first served. Satisfaction 
guaranteed. 



SIGNETICS m f^'ROM 
82S129. 256X4 Bipolar, muth fasier 
than MOS devices 50 NS. Tn- state 
outputs TTL compatible, Field program^ 
abl€, arid features on chip address 
decoding Perfect for mtcro prog ram mmg 
applications 15 pin DIP Wdh specs. 
S2 95 ea 



PROMS! 




%2M 



PROFESSIONAL QUALITY STEREO HEADPHONES 

Here Is the kind of super deal that S. D, is famous for. 
Treat your ears to a super sound at a super price. Soft 
padded ear cushions, lightweight, fully adjustable 
headband, long coiled cord, wide response. $6 
NEW IN ORIGINAL FACTORY BOXES 



INSTRUMENT KNOBS 
Black with brushed aJuminum insert. Medrum size, very 
attractive styie, SPECIAL 5 f OR S1 



MV-50 TYPE LED's 
10 for SI 



3 DIGIT LED ARRAY -75c 

dy LrmoNfx 

0O3MMB. 3 MAN-3 Si^e Readouts In one 
package. These afe factory prime, no4 
fetes ted rejects as sold by others, 
compara lliia phcef 7Sc 3 for $2. 



SALE ON CUT LEAD SEMICONDUCTORS 
Leads were cut for PCB insertion. St ill very useable. 



1N9T4/1N4148 ......... . ....,_. .100/S2 

1N40021 AmplOOPIV ........... ...40/$l 

1N4745A16V1WZener , 20/$1 

EN2222NPNTranstst0f ,. . . .25/$1 

EN2907PNP Transistor 25/$1 

2N3904NPN Driver Xstr , 25/$1 

2N3392 GE Pre-amp Xstr 25!$1 

C103Y SCR. 800MA. 60V 10/$1 




ALL NEW. 

UNUSED. 

SOME ARE 

HOUSE* 



NATIONAL MM5375AA ALARM CLOCK CHIP 
Second generation alarm chip. Six digits, internally 
generates alarm tone, snooze, power failure indicator, etc. 
Very easy 10 use. Outperforms older types like 5316, 5370, 
etc. Perteci for use with our HP 5082-7740 LED readouts. 
S.O. SPECIAL PRICE: $3.50 

miH DATA 



MOSTEIC HKSOStO DIRECT DRIVE ALARM CHIP 
Drives LEO readouts direct, eliminates transistor or IC 
interface circuitry. 4 digit oytptit is non-multiplexed to 
eliminate RFl in clock radio appfications. Has sleep and 
snooze features 40 ptn DIP. Makes a JUMBO alarm clock 
t^y uaing our FND 503 readouts. We show you how. 
INTRODUCTORY PRICEr $3.9$ 



SLIDE SWITCH ASSORTMENT 

Our tsest seller. Includes mtntature and stamtard 
si^es. single an6 muUi^po^tion units. All new, 
first qt^ity, name brand s-witches. Try one pack- 
age and you'H reorder more. Special — 12 for $f 
^Assortment) 




DISC CAP ASSORTMENT 
PC leads. Al leasl 10 different 
vatues. Includes ,001 , .01 , .05, 

plus other standard val ues , 
60 FOR $1 




UPRIGHT ELECTROLYTIC CAPS 

47 mfd 35V-10/$1 68mfd 25V-8/$1 
Brand new by Sprague, PC leads. 




1000 MFD FILTER CAPS 

RMed 35 WVDC liprl^ styte with P C U 
Most pofxjiar V9^ue lor hobbyists. Compare at up 
to $1,1 9 each from Irarchrse type eieartnic parts 
storm.S O. Sfmeiat4ti>rtt 



REStSTOR ASSORTMENT 

1/4W5% andiO%.PCIeads. 
A good mix of values. 200/ $2 





LARGE SIZE LED LA f^PS 
Siffliiar to MV5024. Prime fmctory teaied 
units. We incltide plastic mounting chps 
which are very hard to come Dy. 
Special 5 for $1 



VERNIER DIAL 

From a close out of metal detector manufaciyrer V? 
Turn, 8 to 1 ratio. Internal stops easily removed lo make 
unit multi*turn. 
LIMITED QUANTITY - $.99 EACH 



741 COP AMPS 
Prime, factory lestad and marked Full 
spec on all parameters, Not fe-tesied. 
tuncijonal only, units as sold by oihers. 
741 CH -TO-5 8 Lead Meial Can 3/$i 
741CV - a Lead Mirn Dip ^l%^ 




DUAL 741 C (5558) OP AMPS 

Mini dip. New house numbered units 

by RAYTHEON. 

4 FOR S1 



FET^S BY TEXAS INSTRUMENTS — SPECIAL 5 fof $1 

fnS-TB bul with an imsrmi house number. TO-92 plastic case. M. Channel, 
Jyndiori type FET. 



Signetics. TRI-State Hex Buffer M05 
and TTL mierface to TR I -State Logic. 
SpectaJ; $1 aT97B 



TRANSISTORS 

2M3904 - IStPN 

2N3906 - PKP 

SiSOJ 



Tl POWER TRANSISTORS 
T1P29 NPN Silicon. TO-220. 4/$1 



CT-S005 

WITH FOUR' 
FUKCTiON M£MORrt 



CALCULATOR CHIP 

ByCalTex, 12 Digits. 

With Specs. SI .49 

Factory prime. Not retested 



We do not sell junk. Money back 
guarantee on every item. Ho CO.O. 
Texas Res, add 5% tax. Postage 
rates went up 30%F Please add 6% 
of your total order to help cover 
shipping. 



S. D. SALES CO 

P.O. BOX 28810 
DALLAS, TEXAS 75228 






S.D. SALES ATLAS WINNER 

EIMD OF CONTEST 



R,P. Taylor }r: WB6EWO 
1707 N, Concerto 
Anaheim CA 92807 



SIX DIGIT LED 
ALARM CLOCK KIT 



S. D. SALES CO. 

P. 0. BOX 28810 DALUS, TEXAS 75228 



Thousands of hobbyists have bought and built our original clock kit 
and were completely satisfied. But we have received many requests 
for an alarm clock kit with the same value and quality that you have 
come to expect from S.D. So, here it is! 

E KIT INCLUDES: 

Mostek 50252 Alarm Clock Chip 

Hewlett Packard .30 in. common cathode readouts. 

NPN Driver Transistors 

Etched and Drilled P.C. Board set 

Step Down Transformer 

Switches for time set 

Slide Switches for alarm set and enable 

Filter Cap 

IN4002 Rectifiers 

IN914 Diode 

,01 Disc Cap 

Resistors 

Speaker for alarm 

LED lamp for PM indicator. 



1 
6 

15 
1 
1 
2 
2 
1 
4 
1 
1 

15 
1 
1 




6. 



50 



(COMPLETE KIT) 



Why pay MORE MONEY for our competitor's clock that has LESS 
DIGITS that are SMALLER in size? 

Please take note that we use only first run parts in our kits and 
include ALL the necessary parts. Not like some of our competitors 
who use retested readouts and chips or who may not even include 
switches in their kits. 

60 Hz. Crystal Time Base 



FOR DIGITAL CLOCKS 
S. D. SALES EXCLUSIVE! 



«|>M- 



95 



The kit you have been waiting for is here NOW, and at an 
unbelievable price! Thanks to S.D. Sales you can turn that digital 
clock of yours into a superbly accurate, DC operated, time piece. 

KIT FEATURES: 

A. 60 Hz output with accuracy comparable to a digital watch. 

B. Directly interfaces with all MOS clock chips. 

C. Super low power consumption (1 .5 Ma typ.) 

D. Uses latest MOS 17 stage divider IC. ^vVj 

E. Eliminates forever the problem of AC line glitches. 

F. Perfect for cars, boats, campers, or even for portable 

clocks at ham field days. 

G. Small size, can be used in existing enclosures. 




Kit Includes crystal, divider IC, P.C. Board plus all other necessary 
parts and specs. 




ENCLOSURES! 





& 



PQLLO 



Deluxe Electronic Equipment Enclosures 

fiOSY DOXS are fabrlddt^d of heavy cold relied steel. Tbe front 
pan-sls are of 20 gauqs brushed chrome steel, Line ecreensd aiid 
have a- red Rocker DPDT switch Installed (.except "A" box) with 
gold pt-ated contacts and terminals* CovefS are finis had wjtth 
haked on wrlDkle enamel * 

All cabinets are completely SSSemblsd and suppU^ with 4 
rubber feet riveted in^ Lndividvially pac!j;ed In a heavy duty 
ccTTu§ate<ji pnaile-r carton, chassis. "C" thru ''H" are CR3, 
niclcel^plated over copper for excellent FF conductivity. 



The cl&an deSfgn of tliis Bud 
eficioMjre resMlis in exceilent 
visJbiLity of pan&l rrDunted 
components. Since the cover is Dri& 
piece, it is aa^iiy detach^ far quisle 
access to th? Jnteriar. Base i$ 1/B" 
aluminuin with black t6}<ture finish: 
thecs?wej" is -057 aluminum with 
srrrfjoth lArtiite enaiDel finish. No 
fasteners are enpoBed on the visible 
surfacM. Rubber i^ei fumtshed. 



Compucab series 




A 


5 s/B X a 1/a X 3 


B 


S 1 1/16 >: 3 3/8 X 3 3/4 


C 


7 i/A a^ s/a X s 


D 


S X 2 1/2x9 (tinoMle mtg. avail. 


E 


6 1/2 X J 15/32 Ji 7 1/16 


F 


7 1/2x4 1/2 X 10 


G 


10 1/16 X 3 5/16 x9: 


HA 


5 1/8 X S 1/2 X 4 (BLank Panel) 


J 


5 X -3 1/a K S 3/4 (Sloping Panel) 


K 


4 1/4x7 3/8x11 w/handle 


L 


11 1/B K 1/B K 12 3/4 


ivt 


U 1/B x6 l/a X 16 3/4 



Dl Mtg. bracket a et for D 





MfiS ^7-G 




EASE OF ASSEMBLY 
COLORS 

^"lOD-lJ-BOXcatsinetsaTe finished with bak?d-on 
vinyl Organoisl in deiignof coord ins tsd color 
<ortibinASionh. Cahirttrti hive a tesiturad wrsp around 
base wrEh a smoath vloped front im^fi. Out standard 
colan^m blue (biJu)^lan ttjj gr^y (gy) smlbUirk ihlln] 
!exiin'i& frtr Ehe wrap aroimrf and f»fiy (gy}f while {w) or 
black ihi\-] on lh*? front m-hi^irt. 

CONSTRUCTION 

Our' Labmts* arc ni-adtj entirely t^f Alumirtumj Cor 
5,tTCT>|;th and t^aHC pf hanrtling. 



MBS 3-4-6 3"' 4" &" 

MBS 3-7-6: 3" 7" 6" 

MBK 2-5-5 2" S" 5" 

MBK 2-7-e 2" 7" 6" 

MBK 3-10-11 3" 10" 11*' 

MBS 4-10^10 4" 10" IQ" 

MBK^'10-10 5" 10'^ 10" 

MBK 6-12-10 6" 12" 10" 




2370 
48.35 



Slope 

SC 12100 



SC-12100 
SC -12101 



A 


B 


C 


4\ 


5 


5 


3% 


12 


10 



1Q60 
22.05 



Linear 



ticiuoo 



NOT ALL COLORS S STYLES ARE STOCKED 7 
PLEASE ALLOW 2-3 WEEKS DELIVERY 



MODUUNE 



E tneli 



TiKh 



MCP 



MCH 



MCR 





RC-11100 

•11101 



'iQFncfe 
I04T 23.15 



A 

3\ 
8 



B 

5 
12 



C 

10 
10 



15.60 
3430 



10-4-12 
11^? 

1 9-5-1 ; 
iQ-e-s 

tEl-M 
IOhSII 
lfr?B 
31977 

i[j'7'g 

tO^ll 

■flip's 

H>9T 

lD-g-12 
1D-12-S 



71.6S 

n.25 

30.5* 
21.90 

25.68 
^3i 
Z2,3C1 

22 .BZ 
24,G& 

ir.13 

33-02 
24^:3 
?7.3G 

32.BJ 
Zb.DI 





THE PROBLEM SOLVERS 

214/ ea^-^STO 



KA ELECTRaNlC SALES 

ISSO MAJESTY DR ■ DALLAS. TEXAS 75947 



Poly PakV 



100' S OF BARRELS PURCHASED! 

BUY 'EM FROM THE "BARREL" AND SAVE! 




of any hit 




EXCLUSIVE 'BARREL 

THE BIGGEST INFLATION FIGHTING VALUE EVER! 
TEST ;EM yourself 'N SAVgi 

Every kit cvries iTiDfii'Vy back guarantc*. 





For the first time anywhere. Poly Pak 
mercliAndlsers introduce a new way 
in buying the economical way. Raw 



^ 



VAWPrct KfTrl 
%NT4«a Dtp IC'S 

75 for $1.98 

inn thpbi ni&F iBdudF lot^H, 
•■ i;iki*-r.B^ Rip Rnjks^ rrtunf- 

II KTi HAn-iFAC-nON' 
CBi.No.AA291& UnlfiftLed. 



BARREL KIT r3 

LINEAR OP AMPS 

b1PS_e M 

ra 7S for 

%tH^ irtcSude 7(}13'i. 7-(]'«, 
7a3'i, ceo ^cHcA, A&& li»- 

rlnnlvti iiiarkfd und un' 
iMurki-d. Cst.Ne.4A14],e 



'^ 



eARTItL KIT i 
lN4l4«/it4 
5WITCKIPIO DIODES 



1(M> for £1.98 

Irnftjririe f Jim hup awHch^ni 

tljLHlEft ^^^ ihitntr nrlc«fii 




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'^4000" R£CTiFiER5 

100 for SI. 98 

TtirKm *r# ihc fi.mciii« mitiim 
mJTiiJiiurp rrrlilicn d( lb« 
IN •in on ■•ri«A. MBf !■• 
cluiS* an. /id. IDD, 2ft4l. 
4D0i iOQi. A 00 Bliri 100t> 
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BARREL HIT r$ 
SCB5. THIACS* 

OUADRACS 



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All ihui frnnnue piacNc jhiW* 

MLftrhl AU liiii IP afnp lyitE#, 
Cfet.Na.4A2419 UnteMtod. 




stock from the ^'barreT''. Remember 
the "good ole days^^T They're back 
again. The same way merchandisers 
throughout the United States buy 
from various factories - , ^ their over-- 
runs In barrels. Poly Pak ha« done 
the same. Therefore you are getting 
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OO! 



BARREL MtT .'7 
VOLUME COHtAOL 
BONANZA! «^ -fj^ 

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Hiiurlfi'S, duBlj. vnridC^ of 
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SUBMIMIATURE 

IF TRAHSFORmn 

lOO ^- food, 

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Afna7i;nir. iJKlutl** 4CiAkeB, 
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Fractk tri&ELaJiVTCpr t^^Jr^ TnnH^ 
u/j^itLtrnF*. <>||t,N«.4A2432 



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ROMS-RCCJSTERS 

50 for 
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%• 



141 piin liiCTtC*!* 

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TRANSISTORS 

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ARREL KIT :;i3 
RESISTOR NETWORKS 

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SI .98 




BARREL KJT ;;14 
PRECISION RESlSTOitS 

200 for 
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CrLJia.4A2424 



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mOSFET TRANSISTORS 





60 for $1.98 



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taclcd«a L?EIP traJi«LB|«irt 
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LINEAR a 7400 DIPS 
Unleated 

100 for 
S1.98 

MBfkBfl tr '■ 
tarmml siii. 



^ 



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ZiplER^RiCTtriER MDC 



200 for $1«98 



r I uifira iwi« I 



(iils«4 <u the 



irBte4»d. 



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DIPPE6 MTLARS 



SO for 
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ry ilupn[ijb.j{ 'f-^ in tutfr^N. 

I cm .H« . 4 A2&97 100% lood . 



BARREL KIT f2« 
LONG LEAD DISCS 



150 for 
$1.98 



^ 



'Miuetiioa **!«'". PHnif 
|n*i<hrd OQlr. Ltaoff I'ltilA 
Cat.llA.4A2S9a 10n% fqod 



BARREL KIT ?t4 
HICH VOLTAIC 
RECTI FURS 

160 for 

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Up lit 13.001! ¥oltli* 4 Htllft, 

fliMTXjt ax ill lr«)Jp, 
C«LNd.4A2«02 




BARREL KIT r2S 
MCTAL CAM 
TRANSISTORS 

100 for 
$1.98 

loelwOt^ TO.fi, TO- 1, TO. 
iH. trie,. ii>*t,rird 2fy num. 

b»r«, utimarkr-d «fc. 
Cat.Ni»,4A2ll03 






T -26 



BARREL K 

PLASTIC 

TRANSISTORS 

lOO for 
$1.98 T,^^,^ 

Trpti TO-fX iTci'JM. ^11 

rti.n.tif'jlirtLirera vnrj-l>lii -i.f 
2\ irv. c*t.Ne.4A2a04 



/ 



BARREL Krr :24 
CERAMIC CAPACITORS 

20O for 
Si .98 

Kilt uiiiy ni<] tltn Iwrt^lii 
rofitun dDElHfwi, bul Tftr. 
lurr duraiKft, IZrin Ontri- 
liUl. nio-tElvd t}'p«» liH^I 
C«t.H».4A36a*iaQ^ IIHHl. 




BARREL HlTfl* 
VITAMIN Q CAPS 

75 for 

E*-4f-r llrjv* of ^ii'imiitTM- 
itaUmI c«««. iKXM wpnb (2: 
fiyt the "ulr b»f™l" mtLtn 
rirta jrciu ihv bwcBia-of- 
a- tJ ftUinw. C«t,NCK4A26«7 



BARREL KIT ;?30 

PREFORMED 

RESISTORS 



250 for $1.98 



41ID- 



ha' wmltmrTt tor pe u,«'. 
tTfl(«'tI ttl •VieJ!| RfpcTLin 
■lOfl: *f9* fOn 1.2' wall*- 
|C^l_Ji9^.4JUiSOft IQ9% IwKt 



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METALLIC 

RESISTORS 

100 for $1.98 

M4ui# maatiy bs CornJnf, 
M .(ilir 'ij w»lE*rB_ I ^ [Ik 

:^ to! A 1 lsiwr«J «l 



BARREL HIT jfll 
TRANSISTORS 
WITH A HOLE IN iT 

50 for $1.98 

C*t,N««4A2«lQ Unlaited;. 
Can't DAiD> t^fliifY ht|£ *E 

«n vitb mtn, h4tl# im tniil- 



^¥ 



SARREL KIT ;:34 
TUBE SOCKETS 



100 for 
$1^98 




OARREL KIT £3V 
NEON LAMPS 



■Ad llMT«U- 'I 'a, a'Q, T. !i. 



40 for 
$1.98 




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GERMANIUM DIODES 



200 for 



100 flp rood. 

but t»tUirf fRadr mJIJdQfu 
KfH) llVvl'ftd ".iU. Vnur *d- 

V < n; I .d X Ir 




BARIIEL KIT ff^J 
1 AMP -^eULLETT" 

RECTIFIERS LTntifittd. 



talKuilA DlMkiet-. {i-n^'^lut 

lifi'm. ^i■■v^^r btow* niil iJ'i: 

(j ^ .r:«iL c«LN*^4A24l4 



100 for 
Si38 



lltV. 



g«*^*^*M*" 




«11 turn of btj|t«£«i to 



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a AMP RECTIFIERS 



75 for 
$1.98 




-^CTLIMJt^K" tTPcw atiiCEiB, 
iMaUiorr. iacludei^ all ■vlt- 

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iTi'.U C>t,Wa.4A261 6 

ftARREL kIt ;»1 

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aNlOSS MOBBT 
TRANSISTORS 



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t«d. 



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r*U C«t.Ka.4A3fitT 



BARREL KIT fSt 




BARREL KIT ^40 
PNP HIOH^PDWCR 
Tl^NSISTORS 

20 for 
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DTL'5 IC'S 

75 for 
$138 

T>..i t* prtKa 

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4«^ 

T 



P 



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mJDi««d bvgmlii nuitun. 



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#OLV$T¥REHE CAP: 

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bi«» «« boittlbs 10 bun-la 
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4 0«MW ICNERS 

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S1.98 

hii lur!:' (iiJE tft l3iE[ ArriAKihir 
nttfrr: ll, »l, J 0, 12 to IftV. 
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ItJB.a nitk. H'Thiihk plUR. 
C*LN$,«A2T4a UnteBte^^ 




lARRCL NIT S** 

25 for 

$1.98 L'B. 

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1-WATT ZENERS 

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fflN»i, Dnubtr triijfl, 
Cat,f44,4ft274l 




BARREL KIT ;■■ 

NOSBV LESS 



^1 40 for 
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SLIOC VOLUME 
I CONTROLS '-T^' 

10 for 51.98 

Cit.ria,4AX0i7 

rupcf In Jit-fi. vtiliime coU- 
llral niKkrr ualoads, Aiit, 
hraJunn. wtiiil m buy. Warib 

I of lOft^i mnttrlftl. 



^ 



aARREL KIT ftl 
JUMBO RESISTOR PAK 

100-pc,$1.98 



Cat. N 0.443721 

Acfdortm rtiniii! Mlrnn, urrci- 
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IMJwerji', from V* watt tn 7 
lEflitB. CuicKr fnwli"! Jt 
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ITT -OLASS 4a»» 
RECTIFIERS 

rola4l4<i 

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price • T.'O i-? I Q d^Ov foQl 
Cat.f4a.4A2lt2a 



BARREL NIT r4t 
G.E. J.« WATT 
AMPLIFIERS 



BARREL HIT rSS 
1 DIOtT READOLITS 



$1 



for 
.98 




ruitEi 



IjoMkr trtw. tHiUHT fall' 
outa, w* piudiaaftd tKv^r jtt 
iNiTTallL, TllvH ar« un- 
knoiHiH. Ca^ifa.4A3t«24 



'^^ 



15 for 

I^Ttil|i:in«l clcariHil ita ware, 
ihaui. t . « nrt«T ^e have 

tnLealed. Cmt Na.4A:2T33 



BARREL NITrtS 
MtXCO REAOO 

30 for A 
$1,98 9 

FnctorT rat ami 

TV lCJLV-3'». 1 1 barf at. 4 

Sk? XhSF 1« feCEMUTit*. 

CmL.Ha^mfT»9 lMlavttniL> 





BARREL KIT X7 7 

"BROWN" BODY 
TRANSISTORS 

40 for $1.9 

il-E P-JO arrlnil hiiJi 
vullHjce. Dti.|-||iit|tufl». 

iJiH'irrintlniii'd, I'li-wtr tJibi^ 
0at.NH7.4A274a Uiitsitcd. 




BARREL KIT ^47 

2 'WATT AMPLIFIERS 

50 for 

$1*98 i;,rt«t«L 

B^r trvm tfea b»n«t *a *atw'. 

An ih^f C4e4T Wia 4ob^ 
wsBi EiA URid Mil We eut 
JUjliafcm.Cat.tt^ 1M7 34 ' 

@AHFIEL HIT fTI 
"RED" BOOT 
TRANSISTORS 

40 for $1.98 



BARREL KITrST 
HI-POWER RECTIFIERS 



BARREL HtT i*m 
4UADS1 QUAD^ 

SO for 

9l"v9 t^ M 

Uni#iicd^i Biinta frp ampi 
la ont pajc^^cT' Win' lb* 
facicitr harr^Ji^ |hrh«< »-« 
4tmi kTiDw, {^af, 4A2S37 






BARREL KIT fSI 
SLIDE SWITCHES 



15 for 
$1.98 




iSO-Aniti aludi; fi^ 12, a>l. 
4HV. 100% nnitriiaL Pbe- 



30 for 
$1.98 




AU bli:i^i«A. nixra, fettat, dpdt, 
mifmA-ntarlES, etc. Initian^ 
dtiua kbop piiik Ii3r t mO^A of 
•wlteltlnr JirtijBtti, 



BARREL Kirff* 
SIONAL SILICON 
DIODES 

200 for $1.98 

tndiLtdfa tumntt Aa«T 1 

ol Tvitdhi^t alfxal ^limit 

trpaa^ ail wMmA Irada. 

Cat.H»,4A2S24 L'at««twl. 



.jsr' 



Cat.Ncp.4A2T35 loo ^ r(»Ati,nC'r-N<s^,4A373.6 ^^Cl '% lood 




L^.'IS icrlua. Vlhi LvkI 
Into j(jiir *twn hill! HIkIi 
KVTrr-nt. lil-V, NPN 




BARREL KIT JC9 
2 WATTE RS 

100 for 

$1.98 iQiOft Bood. 

^ K^Q" piqipllmn doft'l 
oa«Ai b«t lataBW '«a la llto 
fewrivL Tf'i m Ul f(4d mi!i^i, 
Al) *rwM4.Cat.N»,4A2T3S 



BARREL HIT lit 
CAPACITOR SPEC I 

100 DCS, 

$1.98 

hajmli of mTli 
nucaa. muldcdj, t4i 
craftijie*. AitJ'-m. *lc, 
100 « «Qod CaLMa..4A273C 




BARREL KIT ^ili 
SUBMIHI RESJSTOR! 



200 for 
$1.98 




PC, u[»rlBl'il ^yp^F c^ii'jr C4id. 

[-rnt€3,t4i''(| Cii mir lt» ua in u bflrraL 
Cat'l<0.4AlT4« 



LX[tS.. ifcapfi,. eolDrv. rootj. 




KIT- lOT 
OHm5 




BARREL KIT g 
STABtSTORS 

50 for 

$ 1 . 9 -^^ J Kfl.4A2 1 40 

laMBTH B^d cam-' 

Ipafar alreiilUT^ AjubI doobla 

IpJyg' Irpa, Ttiiroliliamd tmv- 

tcHT llAa^ PrV £0 t^olt*. 

faiKr fiaU. U teat ^n >avrr 




BARREL 
SQUARE 

60 for 

$1 .98 Cat.1No.4A]0B4 

raotAjd'y pcrQpie air\ nin\.t^- 
UniaA '"aqimrea" wlion ih^y 
latmLn prllTi« sqiLBrB n^TtiA 
mJis 'cm )i& (CL bii/ntli^ Ajiab* 

vn.Jui*S( -wtiUi*. WL. 1 |h. 



BARREL KIT ^ 
NATIONAL IC 

too for 
$1.9S 

Trvca SfrdV^ 74 00 mmwi^, 
iHTLa, fiDHiit rv«t.i#fa»4.'khcJi 
A taJe. cUj^^ llaaar*. *ff. 

L'ju*.i«d. 



3C9O1I 





»T I BARREL ;?•« 

BON AN3EA SILVER MICAS 

100 for $1.98 

Cat. N«^ 4AM IB 

t^ I3j«t iimm mSt*w 
*o lav ia Btica! 
Altaic rod «••. YHriat7 ol 
UtiTaical alaaa A valtun, 
&Ib nrvifega tram lUaDibB- 
loF vrioaa. Wt. t fb. 



ror 



BARREL KIT ^ 
PLASTIC SCRS 

25 for 
$1.98 

Iiopi in^ TieSd liO % 14 
0«<h, l^r lialij 15, 20, tO, 
100, I Ml, ^04 kviu. TO- 
9t. A bar? Tijtt 
CaLH#.4A2l43 



BARREL Krr II04 
TO. 5 PLASTIC 
TRANSlSTOtrS 
CaluHa.4A3:l0t 

40 for SI. 98 

I(lc3udea PNP, NPfJ^ 3N- 

iiBrl««, eta, Unl4iti1«d, but 



» 



BARREL KIT 
^■BUBBLE" 

READOUTS 

12 for 
$1,98 . 

DL-3dB toolkM* macai^an. 
s*fM mJmMjmm. TnttMoJlr *o 
BianjF of 'am. wv daa't 
tTaiaat*^ a a 






BARREL KIT ri2 
4OO0 SERIES ICS 

50 for 
$1.98 

liy NaLJ^nbl, Kfum farKiDri/ 
I11 irnj, A^HtortnTP lU aj tJifp- 

()¥H!rrLin.. ^'ntciiKl, 
CWLNA.4A2C34 




BARREL HIT n^W 
POWER TRANIISTOIIS 

40 for 

$1.98 ^ ^ 

l5i nnit BttndLR K-gQt^O 
pellel IrnrtiiijIcx'H. npn^ hH 
KODd. pyrtriiaiMiil' Irpm « 

qri?te»t*r, hav. millJutts of 
100^ tO(Kl.Cal.P44-4JlZ73T 




BARREL KIT : 

TRANSISTOR 

ELECTROS 

SO for $1.98 ^ 

I1. ^''^qiet'" «■ irftf tha 4ar- 
lOTWs omiSr '*bi km harratiL 
Wc drnt uriai %it aaparaia 
wiite «sct volilkRaii A ^niurf 
19 to dHO mff.Cat, 442T47 



Uataite'ei 



rl£4 ^£ 



riOHi 



? 



BARREL NIT j?ll9 
MOLEX SOCK ETS 
300 for ICC etc" 

$1.98 

Ohlsralatac inirnkmi dondipr Wa 
JTUI 4 (tUien ol 'v«b. I^awl 
fiiT fC *ociMit«, at*. 
CaLMe.4A3t44 



mriTiT^ 



BARREL KtT ;10» .^BARREL KIT n 10 
TERMINAL STRIPS ^ SUPMIESSOR DIODES 

150 for ^^ 50 for 

$1.98 flr«^ $l,98^,,p^,^„„. 

Wide' HPiH <,( l^nfchal strip 7^ , Cat.Kfl,4A313T 

up. iJlr^P TnnniifQcturEra »**'*' Llateittad. hut tlio 
•^ ' of i'ljur oq.pi,F tiar< lh.duii- 

trinL atfr. Ikiublfl ttluff. 



biirr»l 

Wl. 1 



[Jiirrtp ill yuar B.aif*^ 
lb^C«LNi>.4Aai3< 



BARREL NfT ?«* 
PMOTO ELECTRIC 
CELLS 



^ 



'S ^5^ 



BARRCL KIT 

BUTTONS 

FEEOTHRU'S 

100 for $1.98 

TnEtkftaltf wottll a mmaHl 
foftitai. W)d«< Mat. ol b«tt- 
Um-fmmdtkn caiat HA3tfS 
TAKJ ?iOTB7 BF, f-HP, .tc. 
WL. I [b. C*tHQ.4All4l 



10 for $1.98 

iMtxad br factarr. Bi< Job 
fot U4 to saffarata. tQO'% 

4°«'-CatJ*a,4AW a 

BARREL KIT ;l 
MULTf D101T 
READ OUTS 

8 for 
$1.98 

bhrrcld of blemished $, ^ 
and/ or tS HiRJ^ tVadQUtn tn 
URA for "duiiflp". UntBfltJirt 
Cat.No.443 111 



BARREL KIT ;B3 

15 for $1.91 

LII-140T 
VOLTAOi 
REGULATORS 

Factory r-i' Jipi: tad thani mt 
Lirngtli of hiuJn, M«y jEiciuit* 
f^i^. a, if, li!, lE^. I N 3i VQlt«. 
Faw*f tab CaLNa.4A2S2& 



BARREL NIT :: 
CLOCK CHIPS 

5 for '' 

$1,98 ^^4i^„^^ 

531^ — - wMt'a wnwc 
wiik *«ei, w* d£tt*t kaov, 
kot wa Kirt tvftvJa. Mal^T 
KPHxat Wl_ t fHL 




BARREL KIT :i 12 
MICRO MINI LCDS 

40 for 
$1.98 

I Al] t1hil|> iif1)3~ ll'tll. HJLLU]. Ll|l~ 

VarlBty at ■onion . Vl#ld 
CBt.^p.4A3120 



aCD.'sMAY 
BE PHONED 



POLY PAKS 



Torms; Add postnpfe Rated t net 30 
Phone : Wakefield. Mass. (617) 246^3829 
Rstall: 16-lS Del Carmine SU Wakf fi^ld, 

D 20r CATALOG on 
'ICs', Fib«r Optics, 

P*0* BOX 94J LYNNniLD, MASS. 01940 Semr«, Part* 



READER SERVICE 



Circle appropriate Reader Service ^ for desired 
company brochures, data sheets or catalogs and mail 
[n to 73* Include your zip code, please. Send money 
directly to advertisers, LfMfT: 25 requests. 

ADVERTISER INDEX 



propagation 



A2 


AWMki 80 


KG 


KMafn^n 91 


A4 


Atti^SaiQ 7i 


K1 


Kan««o 142 


AID 


Altaj tI7 


Kl 


KEttmrpgimm 131 


Ai 


Amnic^n Ctlil}ril40 91 


K3 


Kani.90d S. It? 


Alt 


Ancom 73 


IC7 


Klii«i 11» 


A12 


Ancrona t44 14« 


K4 


KLM 9. CIV 


AA 


Aptron 3Y 


K5 


KrarkDiiafi 43 


AT 


AflHL 91 


L2 


LsPhCo 130 


A9 


Audialand 3B 


LI 


Lavy 132 


es 


Bdrbsf 139 


Ml 


Matrix 123 


64 


a& F 152 


M2 


Mashnn 10S. 141 


D5 


Budwiv 1JZ 


tm 


MinrMiCTD Mart 123 


06 


Byt* 49 


Iff? 


MwrDw'i t54 


B3 


ftvtfl'trofua 11 


N1 


MatiDfiil MuttiptaK 33 


CI 


C«C« 133 


N2 


Nctrtroirtict Cl\ 


aa 


niiiii—iinfciiiii so 


fi3 


Mnw 140 


C2 


ci«n ©7. i4e 


03 


OptoalaRfoniB 153 


C6 


CofTifn. Sp#CM4rttt 117 


n 


Pktaifw 12B 


CG 


Comm. Eno 12© 


P4 


Pntymorphic 64 


CI 6 


Camrol S^grut 126 


f»2 


PalvF(iJc» 159 


C1E 


Crom^TTic^ 92 


PI 


Rsdici Am. CaHbODk 127 


C14 


CRS \bA 


fta 


HB0inev 123 


C11 


CSdc 133 


^$ 


Haiti Kit 80 


D6 


Oahl 139 


52 


S D Sak!f 1SS, 157 


DT 


OnrlHinfisl t1 


SIT 


StnCliiF 151 


OS 


Dutrofiis M 


S4 


Slap tSO 


E« 


Efatu 9& 


St4 


Smiitv'i Radio 1ft 


£1 


eOM 49 


K 


Solid Gtttt Sahn 12$ 


£7 


Eldo# 13D 


SIS 


SqvthCofn 37 


m 


Eltnra^rafiK 132 


Sft 


SouttiwnT T»fih. S2 


E3 


Ctoc Di«. 131 


S7 


SiMca Ela£. 43 


EQ 


fIflC:. $«parrnarf 13fi 


sa 


SjMirffym Ccimrn. 130 


F1 


Fair 80 


S9 


SphNra B7 


F3 


Frtck 130 


sio 


S5T 130 


G7 


Gamtwr 43 


fiis 


Star Kit! 91 


ai 


G«i*wav 133 


sia 


Swiiwiaik 143 


Q2 


QmuthttT 128 


T1 


T«T* 109 


<13 


GENAU£ 36 


T2 


Tritinbtill 91 


GS 


Giff*^ 43 


T3 


Tyfti 47, 139 


Qi 


GlwJB ViJlty 154 


Ul 


Urn v^ tall RMiio 132 


C4 


God tout n. T4d 


U3 


US Kevntpnniat Partiiint 129 


Hfl 


HjI Coffim. 101 


VI 


Vangiuud 112. 133 


H7 


"Ham ' auH-9«r 1 


V2 


V»rd«fi 49.91, 130, 1 as 


HX 


Ham Radio C«nu]' 147 


VS 


VHF Enfl. 50. &1 


m 


Hamtraniei 121 


V6 


V^44it*K 9>9 


Hi 


Hutth m 


W5 


WavtiMfltir 33 


H3 


Htnrv 29 


Wl 


Wiillman 43 


MIO 


Hofco 1?7 


W7 


Whitflrwjuw 127 


H4 


Hy-Gain 45 


W2 


Wtlwfi 20. Z1 


11 


ICDOM Z, 10 


W3 


l^ir« CofKCfiu 122 


J1 


^mB 1G& 


1«4 


IMbfidastSitfHM 10Q 


J2 


J^&YVtK^ 131 


W€ 


fi6FU€f»D 4S 


Kt 


KAElK. 1&0 


Yl 


YaMii Clil 




From 73. . . 








e0 63 





D NEWSSTAND D SUBSCH/PT/ON 



READER SERVICE 

73 lnc.^ Peterborough NH 034&3 
MAY 1976 

Please print or type. 



bv 

J. H. Meison 



EASTERN UNITED STATES TO: 1 


QtAT] QQ Q3 Oi Oe QB 


to ij 14 tis) ia 30 » 


ALASKA 


?A 


7A 


. ' 1 








I 


7 


7 


? 




AnOEMTINA 


94 


14 


jT 


1 






14 


t* 


14 


14A 


14 




AUiSTRALlA 


IA 


14 


7B 


79 








t 


7 


7 


14 




CANAt 20«i 


'» 


14 


1 


7 








14 


14 


14 


14 




nW<^l.AND 


J 


7 


f 


7 








14 


14 


14 


14 




HaWAM 


14 


14 


ft 


7S 








I 


7A 


14 


14 




INDIA 


7 


ra 


^i 


Tfi 


7B 


rt 


7A 


\4 


14 


14 


tA 




SAPAH 


M 


7 


7 


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weictco 


H 


14 


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7 








1 


14 


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M 


14 


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7B 


7 LI 


7Ei 


7B 


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PUtHTO HlCO 


M 


7 


7 


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7 


14 


14 


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SOUTH AFJIFCA 


7 


7 


3A 


7 


IB 


IB 


14 


14 


14 


14A 


14 


14B 


U. £, Sw n. 


J 


7 


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WESTOMST 


14 


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CENTRAL UNITEE 


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CANAL JiONE 




14 


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WESTERN UNITEI 


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14 


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14 


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7 


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M£X1C0 


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14 


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148 


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14 


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1 

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EAST COAST 


14 


14 


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7 


7A 


14 


M 


14 


14 



A = Next higher frequency also may be useful 
B = Difficult circuit this period 
N - Normal 
U = Uraettled 
D ~ Disturbed 











Name 




Call 


■ 


Address 








City 








State 


Coupon expires in 60 days . 


Zip 

■ » 


. 



1976 




MAY 


1976 


SUN MON 


TUE 


WEO 


THU 


FRl 


SAT 




■41- «WIH 


■ KIT AMIrHt 
4*> 








1 

u 


2 

D 


3 

u 


4„ 


5 

u 


6 


7„ 


8 


9 

H 


10 

N 


11 

u 


12 

U 


13 

U 


M 


15 


16 


17 

U 


18 

U 


19 

U 


20 

D 


D 


22 

D 


D/U 


5^ 

U/U 


25 

u 


26 

N 


27 

N 


28 

N 


29 

IM 



ISO 



Something new 



from Yaesu 




VHF Mobile/Base Station 

2 Meter Transceiver 



Here is a compact, versatile transceiver designed for the active 2 meter 
enthusiast. The FT-221 features all mode operation— SSB/FM/CW/AM— 
with repeater offset capability. Advanced phase lock loop circuitry offers 
unsurpassed stability and clean spurious free signals. Modular, computer- 
type construction offers reliability and ease of service. Preset pass band 
tuning provides the optimum selectivity and performance needed on today's 
active 2 meter band. Join the fun on FM, DX, or OSCAR, with the FT-221 
transceiver— another winner from the world's leader in amateur communi- 
cations equipment- 
Features 

• Complete 144-148 MHz coverage in 8 band segments— 11 crystal 
channels per band segment. (11 xtals = 88 crystal controlled channels) 

• SSB output 12 watts PEP— FM/CW output 14 watts-AM output 2.5 watts 

• Dual rate, concentric VFO dial drive with better than 1 kHz readout 

• Three way metering: S-meter, power output, and FM discriminator 

• Built-in AC & DC power supplies and speaker 

• Built-in tone burst-adjustable 1500-2000 Hz 



See your Yaesu dealer or write: 

Yaasu Musen USA Inc., 7625 E. Rosecrans, 
No. 29, Paramount California 90723 

Yaesu Musen USA Inc., 
613 Redna Terrace, Cincinnati, OH 45215 

Eastern Service Center 
















KLM Multi-2000 . . . already locked in 
as the greatest feature-per dollar VHP transceiver . . . 

Now... both USB & LSB 

for even greater yalue . . . lower , 

beat-inflation pricing! 



great response to the KLM, Multi-2000 VHF 
transceiver by amateurs world-wide has now 
mada it possible to manufacture this fine set in 
quantities substantially larger than the original 
production runs. Result . . . new, value-added fea- 
tures, lowemd manufacturing costs. 

KLM wilt now have more sets to sell so, with the 
Multi''2000A, encourages the buyer by passing 
along a substantial portion of tlie production sav- 
ings. Example: Former price, 795.00. Your 
inflation-fighting price today is 679.00 .,. • itv* 
Ing of 1 16,001 But without extra cost you now get 
Lower Sideband, making the KLM Multi-2000 A 
four mode equipment with NBFM, WBFM, SSB 
(with both USB and LSB) plus CW. Power output 
remains at 10 watts. 

Here truly is trie complete fuir feature VHF station 
for base or mobile. It has both 12VDC and 



144-1 4SMHZ. Phut Jo§h \o&p 
•ynth«»tz*r, 

S«parat« VXO «n<t RIT for full, 
b«twe«n-chAnri«l tuning. 

S4mp)#3i ind i Of «CH)kHi 
mpeaier cipiblllty. 

NaFM.' WSFII, SSa (U5B & 
LSB)/CW. 

aufIMn AC i DC |»QW«f 
■uppM«t« 



• NoIh btpnkir • SquAteh • RF 
Qalnconftnol. 

m $ilBctabl<inowpow«r 
output. 

• ^h««n«mvHy[0,3trVfQr 
iSdbSINAD). 

• 5up#rktr immunity to cm«* 
nMMl./lnt*rmo<L 

• Built-in t»Bt (call) tona and 
touch-ton* provisional 



KLM 



electronics 



1 15VAC supplies buiitHn, is actually ready to op- 
erate right out of the shipping carton. It offers 
highest versatility and crystal stability. Any of 200 
channels can be selected instantly in 10 kHz 
steps by three dials controlling the phase lock 
loop frequency synthesizer setup. Continuous in- 
terpolation within the 10 kHz segments (144-1 48 
MHz) is afforded by VXO for trans. /rec. and RIT 
for receive. There are also three FM crystal posi- 
tions for frequently used channels* 

Check the Mulfr2000A panel in the photo. Note 
ttie convenient, "people engineered" oontrol ar- 
rangements, the simple, positive channel setup 
and the many refinements that contribute to re- 
taxed, enjoyable conversations in any of four dif- 
ferent modes. 

At your favorite dealer or write direct. 



Economically priced t60W 
solid-state Linear Amplifier 




17025 Laurdf Road, ^kirgan Hill CA 95037 
(408) 226^1780, (408) 779-7363 



I^W powar out from MultU2000A 

(or otlmr modal* /brands} with out tun)ng. Automatic RF awltcK- 

6-15W Inpvt, SSB» CW, AM, FM. Inf. 13,S VDC. Alio 144, 220, 

Broad band ... I44>l48llllz wfth- 450MH2 mod«Efl, 12 to 120W out