magazine - Cahaba Technology

magazine - Cahaba Technology
one dollar
ham
radio
b
JANUARY 1976
50-MHz frequency
counter
microprocessors
w~debandl~nearamplif~er 42
432-MHz Yag~
audio power ICs
magazine
Henry Radio
has the
amplifier
you want
-. . .. - .
THE 'WORKHORSE"
The 2K-4 linear amplifier offers engineering, construction
and features second to none, and at a price that makes it the
best amplifier value ever offered to the amateur. Constructed
with a ruggedness guaranteed t o provide a long life of
reliable service, its heavy duty components allow it t o loaf
along even at full legal power. If you want to put that
strong clear signal on the air that you've probably heard
from other 2K users, now is the time. Move up t o the
2K-4. Floor console or desk model ..$995.00
3K-A COMMERCIALhllLITARV AMPLIFIER
A high quality linear amplifier designed for commercial
and military uses. The 3K-A employs two rugged Eimac
3-5002 grounded grid triodes for superior linearity
and provides a conservative three kilowatts PEP input on
SSB with efficiencies in the range of 60%. This results
in PEP output in excess of 2000 watts. In addition, the
3K-A provides a heavy duty power supply capable of
furnishing 2000 watts of continous duty input for either
RTTY or CW with 1200 watts output. Price...$1250.00
4K-ULTRA
The 4K-ULTRA is specifically designed for the most
demanding commercial and militan/ operation for SSB,
CW, FSK or AM. The amplifier features general coverage
operation from 3.0 to 30 MHz. Using the magnificent
new Eimac 8877 grounded grid triodes, vacuum tune and
load condensers, and a vacuum antenna relay, the
4K-ULTRA represents the last word in rugged, reliable,
linear high power RF amplification. 100 watts drive
delivers 4000 watts PEP input. This amplifier can be
supplied modified for operation on frequencies up t o
about 100MHz.
Price...$2950.00
TEMPO T-2000
LINEAR AMPLIFIER
The brand new T-2000 linear is the perfect companion
for the Tempo ONE. It is compact, reliable, and priced
right. Uses two Eimac 8873 grounded grid triodes cooled
through a large heat sink. The T-2000 offers a full 2
KW PEP input for SSB operation and provides
amateur band coverage from 80-10 meters. Provides
a built-in solid state power supply, built-in antenna relay,
a relative RF power indicator, and built-in quality
t o match much more expensive amplifiers. $795.00
K-2000
LINEAR AMPLIFIER
The new K-2000 i s the perfect companion for Kenwood's
TS-520 matched for style and circuitry. The same
specifications as the T-2000... $795.00
TEMPO 6N2
The Tempo 6N2 brings the same high standards of
performance and reliability to the 6 meter and 2 meter
bands. Using a pair of advanced design Eimac 8874 tubes,
it provides 2,000 watts PEP input on SSB or 1,000 watts
input on FM or CW. The 6N2 is complete in one compact
cabinet with a self-contained solid state power supply,
built-in blower and RF relative power indicator. Price...$795
TEMPO 2002
The same fine specs and festures as the 6N2, but for
2 meter operation only. ...$695.00
...
TEMPO 2006
Like the 2002, but for 6 meter operation. ..$695.00
TEMPO VHFIUHF AMPLIFIERS
Solid state power amplifiers for use in most land mobile
applications. Increases the range, clarity, reliability
and speed of two-way communicatios. FCC type
accepted also.
please call or write for complete information.
Henry Ra#o
11240 W. Olympic Blvd.,Los Angeles, Calif. 90064 2131477.6701
7141772.9200
931 N. Euclid, Anaheim, Cal~f.92801
816/679.3127
Butler, Missouri 64730
Tri-Ex Towers
Now you can afford the best!
Free-standing or guyed,
Tri-Ex Towers stress quality.
All towers are hot dipped
galvanized after fabrication
for longer life. Each
series is specifically engineered to HAM operator
requirements.
W Series
An aerodynamic tower
designed t o hold 9 square
feet in a 50 mph wind. Six
models at different heights.
Series
Self-supporting when
attached a t first section will hold normal Tri-Band
beam. Six models.
LM Series
A 'W' brace motorized tower.
Holds large antenna loads
up t o 70 feet high.
Super buy.
T M Series
Features tubular construction for really big antenna
loads. Up to 100 feet.
Free-standing, with motors
to raise and lower.
THD Series
Very popular. Low Cost.
Holds Tri-Band antennas.
Eight models - all support 7
square feet of antenna
at full height in 70 mph
winds. Guyed.
Start with Top-of-the-Line
Tri-Ex Towers. At basic
prices. Write today, for your
best buy.
TOWER
CORPORATION
7182 Rasmussen Ave.
Visalia, Calif. 93277
More Details? CHECK-OFF Page 102
january 1976
1
15 each
Wired and testecI, compleite with
K-1 elel
.
COImmunicdionr
(
2
january 1976
rpcciallrtr
P. 0. BOX 153
BREA, CALIFORNIA 92621
~ ~ u ~ ! ~ ~ , LE.
D F ~ ~ ~
DETERMINING
ITS
$3.00 each
More Details? CHECK-OFF Page 102
magazine
contents
10 synthesized two-meter f m transceiver
Robert W. Wilrnarth, W1 CMR
William R. Wade, K l l J Z
18 50-MHz frequency counter
James W. Pollock, WBZDFA
24 antenna and tower restrictions
Harry R. Hyder, W71V
28 diode detectors
Henry D. Olson, W6GXN
36 microprocessors
ham rad
David G. Larsen, WB4HYJ
Peter R. Rony
Jonathan A. Titus
42 wideband linear amplifier
J. A. Koehler, VE5FP
46 high gain yagi for 432 MHz
Kenneth E. Holladay, K6HCP
50 remote repeater control
Robert C. Heptig, KQPHF
Robert D. Shriner, WABUZO
54 basic troubleshooting
Michael James
60 RAM keyer update
Howard M. Berlin, K3NEZ
64 audio-power integrated circuits
Edward M. Noll, W3FQJ
4
102
64
68
91
97
a second look
72 ham notebook
76 new products
advertisers index
6 publishers log
circuits and techniques
comments
102 reader service
flea market
54 repair bench
ham mart
8 stop press
january 1976
3
Although this new, larger edition of ham radio may seem like a nuisance if your shelves are
designed for the old size, I think you'll soon discover that the advantages of the larger format
far outweigh the slight inconvenience of storage problems. For one thing, the larger page size
allows us t o present larger schematics, so there will be less segmented drawings than there have
been in the past. If you're building a project or tracing out a circuit diagram, switching from
one page t o another as you go through a schematic can be annoying, and often leads t o wiring
errors. The larger page size also means that the photographs will be larger, so you will be able to
more clearly see how the author layed out his original circuit.
However the graphical advantages of the larger page size are small potatoes when compared
t o the big bonus of the larger format: more available space for technical and construction
articles. This 104-page issue, for example, contains as much reading material as any two of our
previous issues - the more than 50 pages of technical articles in this issue, if scaled down t o the
old size, would fill nearly 90 pages. This not only means that we've got t o work twice as hard t o
keep ham radio filled with the kind of articles you want t o read, it also means that we can
provide more basic construction articles and tutorial material that we didn't have room for in
the old format. While we will continue to publish the latest technical developments in amateur
radio, the increase in editorial space will allow us t o broaden our horizons t o include features
which will appeal t o a wider audience. Some of those new features are included in this issue others will be added in the months ahead.
One of those new features is repair bench, a monthly column devoted t o troubleshooting
your own equipment. We have had many requests for such a column but until now, because of
the nearly weekly changes in modern communications technology, there simply wasn't room in
the magazine. The first few repair bench columns will be geared t o basic troubleshooting
techniques, while future columns will attack such subjects as receivers, transmitters, ssb
equipment, vhf fm, RTTY, logic systems, slow-scan television and much more. The column
won't be written by one person, but by different authors who have proven expertise on the
topic covered by a particular column. Although I have several authors already lined up, I'm
looking for others with troubleshooting experience who would be interested in writing some
columns. If you have suggestions for topics, or would like t o contribute, please drop me a line.
The circuits and techniques column which we have published irregularly for the past several
years will once again become a monthly feature beginning with this issue. Circuits and
techniques will also take on a different look in the coming months as we use i t as a vehicle for
presenting new circuits, technical developments and construction techniques which come t o our
attention. If you develop a simple circuit for a special task, are using a well-known circuit in
an unusual application, or run across an interesting circuit or technique in a foreign publication,
we'd like t o hear about it.
The popular ham notebook column which we've been publishing since 1968 will continue t o
be a monthly feature, as will the microprocessor column which we introduced last month.
We're also looking for amateur-oriented construction projects which are built around
microprocessor chips.
We have several other new features being developed which will be published in the coming
months. One of these will be the weekender, a simple project that can be built in a few hours
time over one weekend. A unique feature of the weekender is that we will arrange t o have all
components and a circuit board available from one easy-to-reach commercial source. The first
of the weekender projects is scheduled for publication in the February issue, and we're busily
rounding up future weekender candidates from our authors. If you have a project which you
think might qualify as a weekender, we will be glad t o consider i t for publication. Suggestions
for future weekender projects are also welcome - we may be able to place your idea in the
hands of an author who can come up with a finished product.
Our editorial staff is very excited about the many possibilities of the new, larger size, and
we're looking forward t o making ham radio bigger and better than ever before. Your comments
and suggestions are always welcome.
Jim Fisk. W1DTY
editor-in-chief
The First Base Hit!
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 ICSOA mobile unit.
Impressively built for 26 channels and 10 watts output,
this unit is the perfect teammate of the ICSOA, 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,
Hnd 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 a t
your ICOM dealer now.
Frequency Range
Channels
Power Output
Sensitivity
Bandwidth (Transmitted)
Size
Weight
More Details? CHECK-OFF Page 102
440-450MHz
26
Hi 10 Watts, variable to 1 Watt
.4 microvolts for 2008 uieting
.3microvolts for 1~ D B
15KHz with 5KHz deviation
111x230~260(dim. in MM)
7.2 kilos
INA AD
ICOM WEST, INC.
ICOM EAST, INC.
Suite 3
13256 Northrup Way
Bellevue, Wash. 98005
(206) 747-9020
Suite 307
3331 Towerwood Drive
Dallas, Texas 75234
(214) 620-2780
Any ALPHA Linear Will Give Your Signal
Maximum Legal Power "Punch" .. .
A look through this issue will quickly show that ham
radio magazine i s a t a significant turning point in i t s
eight year history. This is by far the biggest magazine
we've ever published. Not only are the pages larger, but
it also has far more editorial matter, more columns,
more color and yes, even more ads than ever before.
This change is typical of what's happening throughout Amateur Radio. The whole hobby appears to be a t a
turning point which will lead to many changes over the
next few years which could well make today's Amateur
world seem quite unfamiliar.
When we started only eight years ago VHF fm was
unknown to most Amateurs. Slow-scan N was in i t s
very infancy. Almost no Amateur gear was solid-state at
the time, while digital concepts and integrated circuits
were virtually unheard of in amateur work.
Now we suddenly find ourselves at a new starting
point as digital techniques are coming at us in a rush led
by the exciting new microprocessor chips which are
scheduled to change much of our daily world as they
take charge of your kitchen, automobile and workplace.
It goes without saying that their effect over the next few
years on even a relatively simple Amateur station will be
significant.
Arriving almost simultaneously with the birth of ham
radio magazine were the long awaited rules outlining
Incentive Licensing, which have provided the basic
framework of the Amateur licensing structure for the
past seven years.
Again during the past year the Amateur community
has had an excellent opportunity t o debate a t length
another major step in our regulatory history commonly
known as Restructuring. At this writing it appears that
within the next few months these new ideas will become
reality, but possibly in a very different form than originally proposed just a year ago, but definitely including
the much discussed no-code license. The concept of
Reregulation has also been introduced by Commission
officials and should further influence regulations by
which we must conduct ourselves.
The Amateur Radio business community has also
seen many changes. Your all time high acceptance of
Amateur products is permitting many exciting and useful new products to be offered which would have been
out of the question just a few years ago. Attention to
our advertising pages in the months ahead will show
many outstanding surprises waiting for you.
Both ham radio magazine and hr report will be right
there in the middle of these many exciting new developments and will bring them to you step by step as they
unfold. We'll be doing our best to show you what is
happening and just what can be done to insure that both
you and Amateur Radio realize maximum benefit from
these many changes.
Skip Tenney, WlNLB
publisher
6
january 1976
The Ultimate - ALPHA 77D
Ultraconse~ative,super-rugged design
1.8 through 3 0 MHz
8877 Eimac Triode
Full QSK break-in
Vacuum tuning and T I R
Whisper quiet
Full year warranty
$2995 amateur net.
So Just Choose The Model Best Suited
.. .
No-Tune-up - ALPHA 374
Bandpass or manual tuning 10-80 meters
Maximum legal power continuous duty all modes
Three Eimac 8874's
Proven dependability
Full year warranty
Immediate delivery at $1395.
To YOUR Operating Interests And Budget!
Practically Perfect - ALPHA 76
2+ Kilowatts SSB PEP
Full KW CWIFSKISSTV
1OSOM (160M only $49.50)
Eimac ceramic triodes
Fully self-contained
Full year warranty
A Robust "Cool KW" At A Practical $895, Factory Direct
Memo from Drake
One of our observers wrote the other day that we do some rather
curious things from time to time here a t Drake. For example, he
said. we seem to have a penchant for putting wattmeters in
almost everything.
On thinking that over, it is true that the W-4 is a fine device for
up to 2 kW from 1.8 thru 54 MHz. The WV-4 covers 20 to 200 MHz
and we do have W-4 type units in the MN-4 and MN-2000 antenna
matching units. We also have one in the C-4 Station Console, and
a 3 kW meter in the L-4B Amplifier.
Our friend went on to say since we have put s o many wattmeters
in various things, we had probably even put one in the coffee pot
here at the plant. Now obviously that c a r r i e d the whole thing a bit
too f a r after all, we had enough trouble getting one into the
water cooler!
-
When R-F power needs to be measured
consider one of the products
R. L. DRAKE COMPANY
m
-
n
540 Richard st., Miamisburg. Ohio 45342
Phone: 1513) 866-2421 Telex: 288.01 7
See us st SAROC in Las Vegas
More Details? CHECK-OFF Page 102
3
u
january 7976
Q7
JOHN JOHNSTON REPLACED Prose Walker as chairman of the World Administrative Radio Conference Amateur Radio
working group at the group's December meeting in Washington. Prose had been a prime mover in getting this very
important activity organized and going, and despite his retirement from the FCC in July had headed up its September
meeting during the ARRL national convention in Reston and seemed likely to continue with it on a consultant basis
with the FCC. However, the staffing and budget crunch in the Amateur and Citizens Division brought on by the CB
landslide workload put a crimp into those plans so Division Chief John Johnston will be taking it over.
Though Prose' Expertise will certainly be missed, John is expected to carry the WARC preparation effort ahead
with minimal interruption. Under Prose' direction the basic organization had been firmly established and the various
task force chairmen and their groups moving along nicely, so the transition should be a relatively painless one.
900 MHz AMATEUR BAND is receiving consideration both in and out of the FCC. The recent opening of 115 MHz of
spectrum in that region to commercial two-way users will accelerate technical development in that frequency range,
and Amateur Radio (and/or possibly Class E CB) has at least a chance to pick up a portion of the remainder.
Amateur Space And Satellite Communications would find a new band in the 900 MHz region particularly valuable it's high enough to get away from a lot of noise and low enough that atmospheric absorption is not a problem. The
possibility has already been explored in WARC meetings and a proposal for such a band will probably become a WARC
group recommendation.
u
OSCAR 7 is being seriously affected by users putting signals much stronger than needed into it on Mode B. Overloading is causing excessive battery discharge and may be responsible for mode switching and shutdowns. Area coordinators and others are asked to watch for signals causing "pumping," report calls of offenders to W3HUC c/o
AMSAT and advise those nearby of their abuses.
Demonstrating Mode B Sensitivit , W6CG made over 20 contacts in one week running 500 mW to a dipole antenna!
B
REPEATER CROSSBANDING, DOCKET 20113, has been approved and became effective December 15. Report and order will
permit unlimited crossband operation of repeaters in the authorized repeater subbands, covers several related topics
Definition Of "Automatic Retransmission" has been added to the rules, characterizes an "automatic retransmission"
as one initiated by a received signal. Automatic retransmission is restricted to repeaters, auxiliary links or remotely controlled stations such as a remote base which has an auxiliary link station as a part of its system. In
the latter case, the remote base is limited to retransmitting the signals of its auxiliary link station only.
PAPERWORK FOR REPEATERS and other remotely-controlled Amateur stations will be simplified greatly by an FCC
action adopted in November. As of December 1, technical showings will no longer be a required part of the license
application for such a station and technical information will be required only as part of the permanent station
log. Repeater license applicants, for example, need only specify that their proposed station will be remotely controlled. System block diagrams, control details and the like need not accompany the application but must be entered
in the permanent station log. Similarly, repeater-control stations will not even need to specify what repeater they
intend to become a control station for - that's entered in their control station log and the log of the repeater
they control.
Net Result of this important change is to speed up license processing greatly since technical evaluation will no
longer be a part of the license granting procedure.
Note That All Information previously required as part of the FCC file record is still required in the permanent
log. This is spelled out in new Part 97.103b. which replaces 9 7 . 4 1 ~and 97.41e. Control station requirements are
spelled out in new Part 97.103d.
Prohibition Against Portable Or Mobile operation of a remotely controlled station in Part 97.88e has also been
deleted. However, during portable or mobile operation a positive control system is still required and the usual
requirements for ID, logging and notification must still be observed. Note too that the prohibition against portable
or mobile operation of auxiliary link stations has not been relaxed.
REPEATER AND CLUB STATION TRUSTEES should be aware that group organization plans and constitutions are being
checked by FCC legal people to be sure funding of group Amateur stations is not in violation of Part 97.112. All
new applications are checked as a matter of course, and files on old licenses are sometimes pulled for review on a
random basis. Groups whose fund raising systems seem to ask money for operation or
of the station are very
likely to be cautioned.
use
BICENTENNIAL PREFIX LIST in last May's press to^ had a typo which should be corrected. WN1-WN0 can use AK1-AK0 not AG1-AG0 as shown. Use of the alternate bicentennial prefixes is entirely optional, but remember that they don't
go into effect until 05002 January 1, 1976, and are good until January 1, 1977.
ALL IRC$ IN CIRCULATION will be honored for first class overseas postage regardless of date of issue through the
end of 1976, according to latest post office info. After that all earlier IRCs will be void and only latest issue
will be valid.
CANADA GOES AFTER IGNITION NOISE with a new Radio Interference Regulation that takes effect next September 1.
The new regulation will severely limit the permissible radiation from any spark ignition engine, includes autos,
chain saws and snow mobiles, with the one exception of aircraft engines. The regulation will eventually be extended
to include other RFI sources such as power tools and high voltage transmission lines.
8 Q january 1976
American Ham Spirit,
you either have it;
or you don't.
h.
The hams at Dentron have it. That's why we pack so much excitement
into the products we build.
If you're an excited ham who loves to operate all bands, why not complete your station with the 160 meter Top BanderTM? 160 meters is only
a step away from 80 with this remarkable 160 meter transverter. Designed to bring simple, low cost 160 meter capability to any amateur
station equipped for 80 meter CW, SSB, or AM operation. Just "plug
in and play" and you're on 160 meters with 100 watts transmit power
and a super sensitive receiver.
And coupled with the 160AT SkymasterTM, tuning your present antenna
or long wire is a snap.
There is only one Super TunerTM and only one Super Super TunerTM.
Excited Dentron customers around the world have discovered why the
Super TunerTM and Super Super TunerTM are the only antenna tuners on
the market that will maltch EVERYTHING between 160 and 10 meters,
whether it be balanced line, coax cable, random or long wire.
For the ham on the go the 80-10 SkymasterTM offers portability for
tuning that random or long wire antenna. With Dentron SkymatcherTM
you don't have to miss out on the fun of ham radio if you live in a motel
or condominium.
Its Finally here! The Dentron Dual, In-line Watt meter. If you're a perfectionist as we are, you have certain requirements for your station.
Naturally you'll want to monitor both forward and reflected wattage
simultaneously. Tired of constant switching and guesswork? Upgrade!
Reverse scale 0-200 watts
Forward scale 0-200 and 0-2000 RFWatts
Meter accuracy ?5%
Frequency coverage - 1.7 through 30mcs.
Dentron manufactures antennas because our customers deserve better
performance. There have been too many compromise antennas for too
long. We know how much time the average antenna takes to assemble,
that's why we do the work before we ship to you. What a Dentron antenna DOES NOT include is 2 large plastic bags of parts, 5 pages of
instructions and many hours of assembly.
With the SkymasterTM, SkyclawTM, Mobile TopbanderTM, all band doublet
and new Trim-TennaTM 20 meter beam, you'll be proud of their fine
appearance and performance and thrilled with the few minutes it takes
to assemble them.
CATCH THE EXCITEMENT FROM DENTRON .
all Dentron products are made in the USA.
From Dentron Radio or your Favorite Dealer.
160xvB
~~~~~~~~~~
-
sp7q Sn ,,,,A
IlsA
..
All Band Doubt
$24.50 ppd. USA
.%
More Details? CHECK-OFF Page 102
.
january
1976
9
synthesized
two-meter
f m transceiver
This article describes a two-meter fm transceiver containing a 400-channel frequency synthesizer. The transceiver
is designed to operate from a 12-volt dc source. By using
heterodyne techniques rather than frequency multiplication, only one frequency at a time is generated by the
synthesizer, which i s used for both transmit and receive
modes. Lock-up problems are avoided by eliminating the
need to generate the offsets in the synthesizer. With the
heterodyne scheme, the synthesizer changes frequency
directly in 10-kHz increments, which greatly simplifies
its design; you need only dial in the desired transmit
frequency along with the desired receive mode. The
receiver offset, r600 kHz for repeater or zero kHz for
simplex operation, is generated by a separate crystalcontrolled oscillator. An interesting feature of the transceiver is that the modulation is applied directly to the
synthesizer, which results in excellent-quality audio with
simple circuitry.
Frequency
heterodyne techniques,
synthesizer modulation
and modular construction
are combined
in this novel design
general description
Fig. 1 shows the functional elements. The synthesizer
tunes from 12.01 t o 16 MHz in 10-kHz steps. Modulation is applied directly to the voltage-controlled oscillator (VCO) control line from a clipper preamp. In the
receive mode, the clipper preamp i s disabled by switching the B+ line. The VCO output is buffered after which
the signal is split and fed to two double-balanced mixers,
-
By Robert W. Wilmarch, WICMR, and William R.
Wade, K1IJZ, Roberts Road, Wellesley, Massachusetts
02181
10
january 1976
ANTENNA
Y'
TRANSMIT
HETEOSCILLATW
4.3 99667 MHz
MIXER
h
MICROPnwE
CLIPPER
RIEIUPLlFER
BUFFER
+++?I
[
H
I
RECEIVE
HETERODVNE
OSCILLATW
4 0 6 3 Mu* W 6 0 0 1
TRIRER
INPUT
FRONT END
4 0 4 3 Mur (S1MFtEXl
4 0 2 3 MHz ( - 6 0 0 1
SPEAKER
AUOlO
AMPLIFIER
fig. 1. Block diagram of the synthesized 2-meter f m transceiver.
one in the transmit line; the other in the receive line. In
both cases the synthesizer signals are fed into the local
oscillator (LO) ports of the mixers.
In the transmit mode a signal at 131.99 MHz is added
to the synthesizer signal so that the resultant signal
covers 144 to 148 MHz. The front-panel controls are
marked to indicate the transmit frequency. The mixer
output i s fed into a driver amplifier where the signal
level is raised to about 2 watts. This signal in turn drives
a 15 to 20 watt power amplifier. In the receive mode the
transmit heterodyne oscillator and mixer stage are disabled through the B+ line. Voltage is left on the driver
and power amplifier stages since these stages are run in
Overall view. The audio amplifier and o w
tional power amplifier are shown immediately behind the speaker.
- -.
.--.-.-r
-:
72--3$73
class C and consume negligible power without drive.
On receive, the synthesizer signal is mixed with one
of three crystal-controlled frequencies depending on the
desired operating mode. The resulting sum frequency is
the LO frequency required to heterodyne the receive
frequency to the (nominal) 10.7 MHz intermediate frequency. This i-f signal is fed through a crystal filter
which determines receiver selectivity. The circuits following the filter are conventional. In the transmit mode
only the audio amplifier is disabled, again through the
B+ line. Two small relays are used. One switches the
antenna from receive to transmit. The other, in the B+
line, turns various circuits on and off as described above.
A double-pole, double-throw relay may be used for
switching.
synthesizer
The synthesizer generates frequencies between 12.01
and 16.00 MHz in 10-kHz steps. During transmit this
output is heterodyned with a 131.99-MHz signal to produce transmit frequencies between 144.00 and 147.99
MHz. On receive, the required LO frequency is obtained
by heterodyning the synthesizer output with either
121.29 MHz for simplex operation, 121.89 MHz for normal repeater operation, or 120.69 MHz for reverse
repeater operation. Because of the heterodyning scheme,
this synthesizer is simplicity itself. It requires none of
the 1-count detectors, out-of-lock detectors, or count
offset circuits of synthesizers used in multiplier service.'
Above 7 MHz the programmable divider chain of
SN74192s swallows a count due to propagation delays.
This action causes a 1 count (10 kHz) offset in the
synthesizer output frequency from that t o which the
divider is set. This offset is compensated in the heterodyne process t o yield the correct transmit or LO frequency with respect to dial setting at the mixer output.
january 1976
Q
11
-
+12VO
I
&-&'
8.14
FROY Y
lFlG 4)
LY3osu
O
O
~
9
A
16
+N
iO"
I1
1
I
8.H
I3
74192
10
-
IS
4
/Ir
I3
74192
9
1
,
1
0
1
,
74192
m
1
1
I
4
1
,
fig. 2. Programmable dlvlder.
The programmable divider, fig. 2, is unique in that
the +12 through i 1 5 functions are obtained from a
single decade counter chip. This bit of magic is accomplished by using the last 74192 as a downcounter, which
is preset to a 12, 13, 14, or 15. The decade limitation on
the 74192 holds only in an upcount mode. The other
two counters are presettable from 0 to 9, and the string
of three 74192s divides the VCO frequency by a number
between 1201 and 1600 with the programmed inputs set
between 1200 and 1599.
The phase detector and filter, fig. 3, are straight from
the MC4044 data sheet with an extra capacitor on the
filter output t o help supress the 10-kHz ripple on the
VCO con'trol line. Adjustment of the 10k pot in the
filter is accomplished by listening t o the VCO on a
Synthesizer buffer amplifier.
Top of synthesizer showing, left to right. phase detector and fllter; VCO, and reference oscillator.
12
Gbl
january 1976
receiver, tuning 10 kHz off to find a VCO sideband and
tweaking the pot for minimum sideband signal.
The VCO, fig. 4, is an LC oscillator using the MC1648
as the active element. This circuit proved superior in
performance to any of the available multivibrator type
VCOs. Watch out for the MV1401! It's an expensive
($9) wide-range varicap, and again i t proved superior to
the less-expensive diodes. A glance a t the synthesizer
schematics shows that the phase detector, reference
oscillator, programmable divider, and VCO each has its
own LM309 5-volt regulator. A regulator is mandatory
in phase-locked loops to decouple the circuits from each
other. Any modification of this decoupling scheme
should be avoided. Usual RC and LC decoupling techniques do not compare with the use of three-terminal
regulator ICs.
FROM
REFERENCE^
OSCILLATOR
(FIG. 51
s
MC4044P
FROM P R O G R A M M A B L E 4
DIVIDER
(FIG 21
9
B
+I/
I\
1 "F
ION
I
fig. 3. Phase detector and filter.
The programmable divider is constructed on doublesided board with the wiring side a t ground and the cornponent side at +5 volts. The Vcc pins of the IC sockets
are bent out and soldered directly to the 5-volt side,
while the ground leads are brought through the boards
and soldered directly t o the foil. This approach provides
a low impedance Vcc line, which prevents possible
erratic synthesizer behavior.*
The reference oscillator, fig. 5, is a 1-MHz crystal
oscillator followed by two decade dividers t o yield the
10-kHz reference frequency. The synthesizer output is
buffered as shown in fig. 6. A double-tuned output circuit provides a flat response over the full 4-MHz range. A
single-tuned output stage will suffice if the transceiver is
set up t o operate over a 2-MHz range. In this case the
MHz switch may be replaced with a single-pole, singlethrow switch.
From the VCO buffer amplifier the signal is split and
fed to two separate mixer stages. These stages, (fig. 71,
are identical except for minor differences in the tuned
circuits. In each case, the stage is used to add the synthesizer output to that of a heterodyne oscillator. In one
case the sum frequency is the transmit frequency, while
in the other it i s the receive LO frequency. Doublebalanced mixers are used because they happened to be
available. Suitable mixers may be built3 or purchased for
about $7.00 new and perhaps for considerably less on
the surplus market. A mixer stage using a dual gate
1
I
-m
470
KO
(FIG 41
T7
40673 mosfet was tried with apparently satisfactory
results; however, the suppression of the other mixing product was not verified. Other approaches should work
equally well.4
Care was taken to provide 50-ohm terminators to
each mixer port. The synthesizer buffer i s fed into the
LO port, and with the coupling arrangement shown, the
buffer provides an LO signal of +7 dBm. The heterodyne
oscillator signals were adjusted by varying the position
of the output links so that the power at the mixer was
near zero dBm. These adjustments did not appear to be
critical. By using an in-line layout for the mixers, no
instabilities were encountered.
The receive mixer stage is powered at all times, while
the transmit mixer stage and i t s heterodyne oscillator are
powered only during transmit, which is necessary to prevent a receiver birdie in the simplex mode.
modulator
The first attempts a t modulating the transmitter were
along conventional lines; the modulating voltage was
applied to a tuning diode in the transmit heterodyne
oscillator crystal circuit. While this method worked, the
audio quality left something to be desired. After a number of attempts t o improve matters, this approach was
abandoned in favor of directly modulating the VCO in
the synthesizer. The results were indeed gratifying, with
reports of excellent audio quality. Full deviation is
TO BUFFER (FIG 6 ) AND
PROGRAMMABLE DIVIDER (FIG 21
FROM PliDETECTOR/CLIPPER
8 CLIPPER MODULATOR
(FIG 31
fig. 4. Voltage-controlled oscillator. L1 is 4 turns on Amidon T50-6 toroidal core.
january 1976
13
fig. 5. Reference oscillator.
obtained with only a few millivolts of modulation superimposed on the VCO line. This signal level is many times
below that required to disturb the phase-locked-loop
stability.
The clipper preamp, (fig. 8) is a modification of a
circuit originally designed to modulate a tuning diode5
the addition of a Zener regulator in the transmit oscillator. Overtone crystals in the 40-MHz range are used.
The second stages are conventional triplers using a mosfet to minimize oscillator loading. Tripler stage output is
through a one-turn link.
During tuneup, remember that a final frequency is
the sum of the synthesizer frequency and that of the
heterodyne oscillator. The reference oscillator should be
adjusted first, then the transmit heterodyne oscillator, to
produce the desired output transmit frequency. A frequency counter is recommended for this procedure. The
receive heterodyne oscillator crystals should be adjusted
by tweaking their series capacitors for best received
audio.
receiver front end
The receiver front end (fig. 11) i s similar to a circuit
described in 1968.6 Only minor changes were made in
the rf and mixer stages. The original fets were replaced
with 40673s, and the mixer output matches a crystal
filter. Gate-protected fets eliminate the need for diodes
at the antenna. With gate protection no special precautions are necessary in handling these transistors; however, the 3N128 i s not protected and care must be exercised. The mixer output impedance is determined primarily by the resistor across the output tank and is
chosen to match the crystal filter.
The front end and i-f stages show a direct connection
to the crystal filter. This is fine if the physical layout is
close and there is no dc return in the filter. If a dc return
is present, a blocking capacitor must be used to prevent
Transmit and receive mixers.
where several volts of modulation were required. Since
only millivolts are now required, the output stage was
changed to a simple emitter follower, eliminating several
components.
heterodyne oscillators
The heterodyne oscillators are shown in figs. 9 and
10. The circuits differ only in the number of crystals and
2
8
4
O0'
FROM VCO
(FIG 41
fig. 6. Synthesizer buffer amplifier. L1 and L2 are 2 0 turns
no. 2 8 ( 0 . 3 m m ) o n ll.%''
(6.5mm) form. Output links
on.L2 are each 5 turns.
14
january 1976
,,*
L2
MCI35OP
3
5
m
7
6
DOUBLE BALANCED
MIXER
FROM HETROOYNE
OSCILLATORfS)
(FIG 101
IN3819
-
=
SIENAL
O$
5)
5r ::
LZ
FROM
SYNTHESIZER
BUFFER
(FIG 6 )
LO
=
GNO
-0
?
7"'
L1.L2
Ll,L2
OI
Transmit stage. 4 turns no. 18 (l.Omm], airwound, 114"
(6.5mm) I D , %" (13rnm) long. L 1 tapped at 1 turn.
2-turn link on L 2
200
Receive stage. 5 turns no. 18 (l.Omm), airwound, 114''
(6.5mm) I D , 112" (13mm) long, L 1 tapped at 1 turn.
2-turn link on L 2
fig. 7. Mixer. One each is required for transmit and receive. L1 and L 2 are 4 turns each on the transmit board and 5 turns each on the receive board.
sufficient audio in narrowband fm service. The RCA
CA3089E linear integrated circuit is a complete fm i-f
subsystem (fig. 12). While this IC was designed for wideband use, it's possible t o realize 290 millivolts of recovered audio for +5-kHz d e ~ i a t i o n ,which
~
is ample t o
drive the audio stage t o full output. The squelch control
short circuiting the mixer drain voltage. If the circuits
are t o be separated physically, a coaxial line must be
used for shielding. In this case the line becomes part of
the mixer tank circuit, thus requiring a smaller tank
capacitor than the 56 pF shown. A good rule of thumb
for coaxial cable is 30 pF per foot. The LO input from
fig. 8. Clipper preamplifier.
MICROPHONE
2 7h
2~3904
0 1
'1-
TO v c o
(FIG 4 )
821
560k
47°F
the receive mixer stage is amplified and applied t o the
40673 front-end mixer through a 5-pF coupling capacitor. Signal level should be about 1.5 volts.
i-f subsystem and audio
The receiver is a single-conversiondevice. While single
conversion has certain advantages, the trick is t o recover
operates smooth1y with this device and doesn't have the
annoying pop-out characteristics as in some circuits. A
tuning or signal-strength meter may be used with the
circuit. However, i t was decided not to include this feature. Instead, pin 13 is used as a t e s t point for receiver
front-end tuneup.
The Q of the quadrature coil across pins 9 and 10
fig. 9. Receive heterodyne oscillator.
+l2V
L
Xoo0
P
II
II
x
~
l
l
L
j
f
TO DOUBLE
OI
BALANCED
(FIG 71 M I X E R
3Nl28
MODE
40 2300 MHZ ( - 6 0 0 kHz1
404300 MHz fSIMPLEX)
406500
MHz
(+6oo ~ H Z J
L1
7 turns on Amidon T50-6 toroidal core
L2
6 turns no. 1 8 (1.Omrn). airwound, 114"
112" (13mm) long. Link is 2 turns
n T50-6 toroidal core
january 1976
15
+lZV
m
OOUBLED
BALdNCEO MIXER
(FIG 7 )
fig. 10. Transmit
heterodyne oscillator.
;
Receive heterodyne oscillator.
4
L1
7 turns on Amidon T50-6 toroidal core
L2
6 turns no. 18 (1.Omm). airwound.
(13mm) long, Link is 1 turn
L3
3 turns on Amidon T50-6 toroidal core
Ih"
(6.5mm),
112"
determines, t o a great degree, the level of recovered
audio. The RCA t e s t results7 were for a Q of 120. Using
an available core, a value of 220 was measured, which
resulted in somewhat more recovered audio. This value
of 0, however, was reduced to a value consistent with
the sensitivity of the audio amplifier by simply padding
the coil with a suitable resistor. The effect is to greatly
reduce the sensitivity of the circuit to temperature
changes. Stability of this stage may be checked by looking at pin 9 with an oscilloscope. If the circuit is oscillating, a square wave will be seen.
A 2N3819 junction fet matches the crystal filter to
the CA3089E. Because of the very high input impedance
of this transistor, the filter load resistor from gate to
ground i s chosen according to the requirements of the
filter. Stage gain isn't critical and need not be more than
necessary to overcome the filter insertion loss. Any
audio staae with sufficient sensitivitv, mav be used. The
~ ~ ~ 9 i s0a 2
2-watt
6 amplifier requiring only 200 millivolts of drive.
.
40673
40671
AN
IN
+BV
L I . L4 5 TURNS
L 2 L 3 4 TURNS
1/4- I D
1/2' LONG 1 0 6 x I 3 an)
NO re A% W I P E 11 0 mml
X SELECTED TO
MATCH FILTER
i
~5
2 4 T U W S NO 28 A W WIPE 0 3 mml
ON 114' 1 0 6 m
J D l A M T E R FORM
m
120
2'L 1.L4
5 turns no. 18 (l.Omm), airwound,
lh" (13mm) long
fig. 11. Receiver front end.
16
january 1976
I/r"
(6.5mm) ID.
L2,L3
4 turns no. 18 (l.Omm), airwound,
%" (13mm) tong
L5
24 turns no. 28 (0.3mm). on
form
l/r"
I/."
(6.5mm) ID.
(6.5mm) slug-tuned
FROM RECEIVE,
FRONT DYD
(FIG IIJ
fig. 12. I - f subsystem and audio.
The rf driver amplifier, fig. 13, is conventional and is
driven directly from the transmit mixer stage. Output is
about 2 watts and the circuit will match a 50-ohm load.
If 2 watts is sufficient, the output chain may be terminated at this point. For additional power, an amplifier
such as the VHF Engineering unit shown in the photo
provides output in the 15 t o 20-watt range.
Standard copper-clad board and point-to-point wiring
are used. A minimum of tools are required and the difficulty of making printed boards i s avoided. A n advantage
of the modular approach is that a circuit can be completed, tested, and set aside until the overall unit is ready
for assembly. All interconnecting lines use small coaxial
cable where length is not critical, which permits flexibility of the final layout. Rotary wafer switches were
chosen for the frequency select controls. While significant space saving can be achieved by using BCD-coded
thumbwheel switches, a rotary format affords a definite
2 turns no. 16 (1.3mm). airwound, 5/16" (8mm)
3/16" (5mm) long
ease of operation.
This transceiver has given trouble-free operation for
about a year with excellent signal reports. While heterodyning, digital-frequency synthesizers, and synthesizer
modulation are all well-known processes, the combination of these features offers an attractive approach t o
those who like to try something different.
references
construction
~1,L2
a A
TP
ID,
1. P.A. Stark, K20AW. "Frequency Synthesizer for Two Meter
FM," 73, September, 1972, page 99.
2. K. W. Robbins, W I K N I , "Six Meter Frequency Synthesizer,"
ham radio, March, 1974, page 26.
3. W. Ress, WAGNCT, "Broadband Double-Balanced Modulator," ham radio, March, 1970, page 8.
4. G. Vander Haagen, K8CJU. "Hot-Carrier Diode Converter for
Two Meters," ham radio, October, 1969, page 6.
5. D. De Maw, WICER, "An F M Pip-Squeak for 2 meters,"
QST, March, 1971, page 21.
6. 0. Nelson, WBZEGZ, "The Two Meter Winner," ham radio,
August, 1968, page 22.
7. RCA Application Note ICAN-6257.
ham radio
L3
L4
fig. 13. R f driver amplifier.
12 turns no. 22 (0.6mm) enamelled wire, closewound
on 3/16" (5mm) mandrel
5 turns no. 16 (1.3mm), airwound, 5/16" (8mm) ID.
LIZ" (I 3mm) long
jsnuary 1976
17
six digit
frequency counter
A frequency counter has several advantages over a frequency standard. Instead of listening and tuning for
crystal-oscillator harmonics on a receiver, a counter can
provide a direct readout in frequency from the signal
being measured. An instrument such as this can be a very
valuable asset for the amateur who likes to build his own
variable-frequency oscillators, transmitters, and receivers. With this frequency counter I was able to align a
homemade crystal filter for an ssb rig, using the counter
to pinpoint the exact location of the filter passband.
When the counter is used with signal generators, precision alignment of amateur equipment is a snap.
The frequency counter described here and shown
schematically in fig. 1 is designed for use in the hf spectrum to 50 MHz, with a signal at the input having an
amplitude of about 50 mV rms. The digital readout displays the frequency in kHz with resolution to the nearest 100 Hz. Construction cost of the counter is about
$50 including the power supply and cabinet. The cost
will be lower if the ICs are in your goodie bin. Printed
circuit boards are not available for this project. The entire counter, with the exception of the power supply,
was built on perfboard - the kind with holes on a 0.1inch (2.5mm) grid.
The goal of this article is to present a working design
for a high-performance instrument that requires a minimum of ICs. However, I'd like t o offer some observations based on experience with the project. I've noticed
that the 50-MHz response is largely device-dependent. I
had to select SN74S00 devices to get the counter t o
squeak up to 50 MHz. The ICs used in the counter were
obtained from Poly Paks, as was the SN74196 decade
counter. With the prescaler circuits published in ham
r a d i ~ l , 'the
~ . ~ counter should work well into the
432-MHz range.
18
january 1976
The heart of the counter i s a crystal-controlled oscillator. This 1-MHz source is a free-running multivibrator
made up of two NAND gates ( U l A and U1B) with a
crystal as the frequency determining element. The
220-ohm resistors bias the gates in a class-A amplifier
condition so that the oscillator is self starting and sustaining. The remaining two gates in the quad NAND
package are used as buffers to isolate the oscillator from
the loading effects of the IC stages that follow. U1D
provides a buffered 1-MHz output to a BNC jack on the
rear panel of the counter. The 1-MHz output is a very
close approximation of a square wave, rich in harmonics,
and provides a means of checking the oscillator with
WWV. It also can be used for checking out the counter
itself. If the 1-MHz output is coupled to the input jack,
the counter will display 1000.0 kHz. The trimmer capacitor in series with the crystal is used in the zero beating
process.
The frequency counter performs by sampling the input signal for a finite period of time. For example, if we
were to couple a 1-MHz signal to a chain of decade
counter stages for exactly one second, then 1 million
pulses will have been counted. If the sampling time is
reduced two orders of magnitude to 0.01 second, then
the counter will register 10,000 pulses. Thus if 10,000
pulses are counted for each 1 MHz, the least-significant
digit on the counter would represent 100 Hz. It's easy to
see the importance of having a device that will perform
the function of gating the unknown frequency with
great precision.
The time-base divider chain i s composed of four cascaded decide counters (U2-U5) followed by a flip-flop
By Jim Pollock, WB2DFA, 6 Terrace Avenue, New
Egypt, New Jersey 08533
fig. 1. Frequency counter schematic.
(U7) that divides the crystal oscillator down to a frequency of 50 Hz. The-flip-flop hastwo oppositely phased
outputs, 50 Hz and 50 Hz. The 50 Hz output is 180 degrees out of phase with the 50 Hz output. Each output is
a symmetrical square wave that is logic 1 for 10 milliseconds, and logic zero for 10 milliseconds, for a total
time period of 20 milliseconds. The 5 m f r o m flip-flop
U7 controls the input gate (U8B). U8B will only pass the
amplified input signal from the unknown source when
the m a t pin 4 of U8B is logic 1. Thus U8B gates the
unknown frequency for 10 milliseconds.
The decade counters in the time-base divider chain
are connected in a divide-by-5, divide-by-2 configuration. The output frequency of each decade counter is
1/10 the frequency of the input. The output of each
decade counter is a symmetrical square wave. The sche-
matic of fig. 2 shows in detail how the decade counter
functions when connected in this fashion.
display strobe logic
The display strobe logic (U6, U7, U8) synthesizes the
timing sequence for sampling the input frequency, resetting the decade counter bank before each sampling
period, and strobing the LED displays once for each
completed sampling period. The timing diagram, fig. 3,
illustrates the relationship between these signals. "F" is
derived from the output of U8C, pin 8. The total time
period for F is 20 milliseconds, which is de.termined by
flip-flop U7, as discussed earlier. The duty cycle of F is
determined by gating the B, C, D, and E signals together.
You'll note that F is high for 11 milliseconds and low
for 9 milliseconds, and that the displays are blanked out
january 1976
19
during this 11 milliseconds of each sampling cycle. The
display strobe switch, 03,is held in cutoff as long as F is
logic 1.
The RESET pulse, E, goes low for the first 1 millisecond of the sampling cycle resetting decade counter
U9 to the 0000 state. E is inverted by U8A to provide
the proper reset signal for the remaining decade counters
(U10-U14).
During the 10 milliseconds that follow the trailing
edge of E, the input frequency to be counted is registered by the decade counter bank. The LED displays are
is used as the clock input, and the output of the first
flip-flop (pin 12) i s connected t o pin 1 to drive the
divide-by-5 portion. The counting function i s performed
in the binary coded decimal format. Pin 3 is used as the
reset input for initializing the decade counters to the
0000 state. A logic 1 at this input will reset the SN7490.
When pin 3 is logic 0, the SN7490 advances into each
succeeding count state as dictated by the clocking signal
at pin 14.
The SN74196, on the other hand, is nothing more
than a super-fast SN7490 and operates in much the same
manner. The subtle differences are in the pin configuration and the resetting scheme. Unlike the SN7490, the
Vcc and ground pins on the SN74196 are 14 and 7
respectively; on the SN7490, they are 5 and 10 respectively. Pin 13 on SN74196 is the reset input; a logic 0 as
this input will jam the counter into the 0000 state. The
counter can only advance when pin 13 is logic 1. This
one criterion is opposite that of the SN7490. NAND
gate U8A solves this dilemma by providing oppositely
phased reset signals for U9 and the remaining counters in
the decade counter bank.
decoder bank
Logic circuitry for the 50-MHz frequency counter is built on a
section of perf-board. Voltage regulator ICs are mounted on aluminum panel which is sandwiched above the perf board o n
standoffs.
blanked out during the count-up cycle; otherwise, the
displays would show a blur of 8s from the fast count
rate. When the sampling has been completed, the input
gate is opened, and the decade counter bank no longer
receives pulses from the input buffer. At this point in
time F goes low; Q3 is switched into saturation, and the
LED displays indicate the results accumulated during the
sampling period. This process is repeated 50 times per
second. Because of the persistence of the human eye, the
displays seem to be on continuously. Since the counter
gets an update 50 times per second, the counter will
follow rapid changes in frequency, such as those encountered when tuning across the band. The counter will
update changes in frequency with no apparent time lag.
U15 through U20 are BCD-to-seven-segment-decoder
ICs. These SN7446s translate the BCD information from
their respective decade counters t o form digits in the
seven-segment format. The SN7446s feature leading-zero
blanking, which is employed to eliminate any ambiguity
caused by one or more zeros preceding the mostsignificant digit. For example, a frequency of 00142.7
kHz is more recognizable when presented as 142.7 kHz.
Blanking out the unnecessary zeros makes the display
much easier to read. Special logic i s designed into the
SN7446 to provide this feature. The ripple blanking
logic looks for a logic 0 from the ripple blanking output
(RBO) from the next most-significant digit. This condition occurs when the next most-significant digit above
that one is also a zero. The ripple blanking signal propagates from the most-significant digit to the leastsignificant digit desired in the zero blanking scheme.
I f you refer to fig. 1, you'll notice that the ripple
blanking originates from U20 (the most-significantdigit)
and is passed down the line t o U17. The ripple blanking
output (RBO) appears at pin 4 of U20 and is fed to the
ripple blanking input (RBI), pin 5 of U19, and so on.
decade counter bank
CONNECTED
The decade counter stages (U9-U14) are cascaded in a
manner that allows them to function as a system for
counting a series stream of pulses. U9 is the most important link in the counter chain and is an SN74196, a
high-speed device capable of performance in the 50-MHz
region. The SN7490 decade counters are rated at 15
MHz. Therefore, the frequency range is very dependent
upon the input buffer and the SN74196. Since U9 will
operate at 50 MHz, the frequency propagated to the
next stage will be, at most, 5 MHz. Each succeeding
stage will receive decreasing orders of magnitude of the
frequency presented to U9.
The SN7490s are connected in a divide-by-2, divideby-5 format for use in the decade counter bank. Pin 14
20
january 1976
15 1 S Y M U E T R I C A L - l O D l V i D E R
fig. 2. T h e t y p e SN7490 connected as a symmetrical divide-by-10 counter.
Pin 5 of U20 is grounded since the ripple blanking process originates at U20. The ripple blanking feature can
be disabled by simply connecting pin 5 on U20 to
+Vcc,. Pin 5 (RBI) on U15 and U16are tied to +Vcc2;
therefore, with no signal present at the input gate the
counter will display only the least two significant digits
as zeros.
Unlike the other ICs in the project, the SN7446s are
enclosed in a 16-lead dual inline package. Pin 16 is the
+Vcc input and pin 8 i s ground. The output pins, 9 to
14, are open-collector outputs capable of sinking 20 m A
LOCATION OF
WAVE FORM
input buffer-counter preamp
IC PIN
NUMBER
1
I
U5-12
I
1
I
I
I
I
I
I
I
I
I
n n n n
Us-l4, I (
I
I
U
I
I
I
B C D
I
!+BEGINNING
OF
I
LDISPLAYS
I
U6-12
RESET
I
W E N D OF SAMPLING
I
PERIOD
UB-8
I
I
I
I
I
I
1
$COMING
BLANKED OUT
COUNTER
1 ,
I '
REGISTERS+
~
I
~r D I S A&
BLED !
~
~
INPUT GATE
PULSES:
1
I
SAMPLlNG C
I I
0 1
~
I,
pointed out earlier, the average dc current through the
segments is 6.75 mA.
The MAN-Is are common-anode displays. Commonanode displays can only be used with decoder ICs like
the SN7446 because of the polarity of the opencollector outputs. Common cathode displays will not
work in this project. The MAN-1 display has its segments
partitioned into three groups. It i s necessary t o tie all
three common elements together (pins 3, 9 and 14) to
get all of the segments t o light up on command. Litronix
Data Lite 707 and the Opcoa SLA-1 are excellent
substitutes.
I
l C L E d
I
20
MILLISECONDS
fig. 3. T i m i n g diagram showing display strobe logic, reset, and
input gating.
when switched on. The 220-ohm resistors in series with
each segment on the LED displays limit the current to a
peak value of 15 mA per segment. However, since the
displays are strobed on for 9 milliseconds in each 20 millisecond sampling cycle, the average current per segment
is (9 milliseconds/20 milliseconds) (15 mA) = 6.75 mA.
The input buffer stage is designed to amplify lowlevel signals t o the amplitude necessary to drive TTL
logic circuitry. The transistors chosen for this two-stage
amplifier are the HEP 709s by Motorola. The gainbandwidth product of these devices is 600 MHz, which
makes them well suited for this application. Their low
saturation voltage (VCelsat,) is on the order of 0.3 volt,
low enough to ensure a logic 0 at the input of a TTL
device.
Resistor R1 acts as a buffer between the transmission
line input and the base circuit of 0 1 so that the incoming signal is not clipped or loaded down by the baseemitter junction of 01. The parallel combinations of
C1-C2 and C4-C5 provide coupling from several kHz
through the vhf region. Ceramic capacitors become
somewhat lossy and inductive at high frequencies, so
silver-mica capacitors (C2 and C5) are used t o provide
additional coupling at the high-frequency end of the
counter range.
Diode CR1 i s a high-speed switch that protects 0 1
from negative-going peaks appearing at the base-emitter
junction. Resistor R4 matches the collector circuit of Q1
to the base circuit of Q2, and also contributes to overall
amplifier stability. C3 is a 10 pF silver-mica capacitor that
compensates for the base-to-emitter capacitance of 02.
To keep stray capacitance to a minimum, short com-
SEGMENT
IDENTIFICATION
led displays
The LED displays used in this project are equivalent
to the famous MAN-1. The pinout configuration and
schematic are shown in fig. 4. The forward-bias threshold on each segment is slightly more than 1.6 volts. This
property alone makes i t virtually impossible to check
out junction continuity and performance with multimeters equipped with an ohms-scale voltage source of
1.5 volts. The best way to check out the LED displays is
to use a 4.5- to 5-volt supply with a series currentlimiting resistor of 220 ohms. I f purchase of MAN-Is
from some of the surplus dealers is contemplated, this
setup will prove valuable in judging display performance
on a segment-by-segment basis. The displays will appear
to be a little dimmer in the finished counter because, as
3
10
W
li
2
PINOUT CONFIGURATION OF MAN-I,
D L - 7 0 7 OR S L A - I DISPLAY
7
6
DECIMAL POINT
e u : " " "
fig. 4. Pinout connections and schematic o f the
MAN-1 LED display.
january 1976
21
ponent lead lengths are of prime importance. The braid
of the coax cable should be soldered as close as possible
to Ql's emitter t o prevent ground-loop problems.
Printed-circuit boards with the customary ground planes
are not necessary if the layout is as neat and compact as
possible. The amplifier should be near U8 since the collector of Q2 drives pins 12 and 13 of U8.
input amplitude voltmeter
Since digital logic has a threshold with respect to triggering levels, a means of monitoring the input signal level
fashion is to divide the current demand of the frequency
counter so that the regulators operate well below their
maximum ratings. The dual power supply also provides
excellent decoupling between the decoders, display
switching circuitry, and other parts of the counter logic.
sensitivity measurements
These measurements were made with a Tektronix 191
constant-amplitude r f generator, a Hewlett-Packard
audio oscillator, and a Tektronix 7000 series scope. The
following results were observed with a sine wave input.
12 VDC 0
" ";I,
5 0 PIV
BRIDGE
5 0 PIV
117
VAC
A
TO OSCILLATOR
TIME BASE
DIVIDER. lNPUT
BUFFER.
DISPLAY
STROBE LOGIC.
DECADE
COUNTER
BANK
TO DECODERS
ONLY
8
DISPLAYS
X HEAT SINK
MOUNTED
AXIS OF SYMMETRY
3
fig. 5. Dual 5-volt power supply.
is necessary to ensure that the counter chain is receiving
enough drive to operate reliably. Insufficient drive level
can cause triggering errors, in which case the counter
counts only a few pulses that happen to break the threshold level.
This circuit consists of an fet voltmeter equipped
with an rf probe. The meter i s calibrated to read 5 volts
peak-to-peak or 1.78 volts rms full scale. The 25k trimpot in series with the 0-50 microammeter is used to
calibrate the circuit. The I k trimpot provides an electrical zero adjust. Calibration can be done with any highfrequency source of known amplitude. The 1-MHz output at pin 11 of U1 has an amplitude of about 3.6 volts
peak-to-peak, which can be used if no other calibrated
source is available. Before beginning the calibration, the
meter should be both mechanically and electrically zero
adjusted. The zero adjust on the front panel of the meter
should be checked before you apply supply voltage to
the fet voltmeter circuit.
power supply
The power supply, fig. 5, i s straightforward thanks to
the LM309K voltage regulators. Two 5-volt supplies are
derived from the 9-volt dc supply. The Vccl supply is
connected to the Vcc pin of all the ICs except the
decoders. The VCCZ supply powers the decoder ICs and
the LED displays only.
The purpose of splitting up the power supply in this
22
january 1976
LM309K
BOTTOM VIEW
Upper and lower cutoff frequencies of the counter were
noted with respect t o a given input amplitude. These
numbers represent input levels necessary to ensure reliable triggering of the decade counter stages.
amplitude
( m V rms)
lower cutoff
frequency
(kHz)
upper cutoff
frequency
(MHz)
10.20
14.00
18.15
23.00
45.70
The counter works well with signal levels up t o 1.5
volts rms (4.5 volts p-p). At greater amplitudes, the basecollector junction of 0 1 i s forward biased during the
positive peaks of the input signal thereby degrading i t s
vhf performance.
references
1 . Bert Kelley, K4EEU, "Divide-By-Ten Frequency Scaler,"
ham radio, August, 1970, page 26. See also "Short Circuits,"
ham radio, April, 1971, page 72.
2. F. Everett Emerson, WGPBC, "Advanced Divide-By-Ten Frequency Scaler," ham radio, September, 1972, page 41. See also
"Short Circuits," ham radio, December, 1972, page 90, and
"Comments," ham radio, November, 1973, page 64.
3. F . Everett Emerson. WGPBC, "Circuit Improvements for the
Advanced Frequency Scaler," ham radio, October. 1973, page
31.
ham radio
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1 1 1 1 1 1 1 1 1 1 1 1 1 J
january 1976
23
antenna and
tower restrictions
A complete discussion
of deed restrictions,
zoning ordinances
and building codes,
and how they may affect
that new antenna system
you want to install
When planning to buy or build a new home an amateur's
first thoughts are inevitably of antennas. How many
towers, and how tall shall they be? He may remember
stories of amateurs who have been faced with lawsuits
because of deed restrictions or zoning regulations, but
rarely i s this an overriding consideration i n the choice o f
a house or lot. Let the wife pick out the house first -- he
can worry about those things later. This should not be.
The dangers t o ham operation are real, and unfortunately seem to be getting greater.
No one can assume that he has an inalienable right t o
do whatever he wishes with his property. Like all of our
rights, they are subject to many limitations. If you take
the attitude that some vaguely-worded deed restriction
or zoning ordinance will be decided in your favor by the
courts, you may be right. However, i t could still cost
you thousands of dollars in legal fees to establish your
rights, and unless you are inedpendently wealthy and
enjoy litigation, i t could by a Pyrrhic victory.
I recently bought a lot and built a house, and in the
course of doing this learned a great deal about the subject. Because of various restrictions, I rejected lots that
were otherwise very desirable from the standpoints of
location and price. Eventually I found a lot that was
satisfactory from all standpoints, but i t was not easy.
This article will describe the nature of the problems you
may be faced with, and what you should do to minimize
your risk.
Perhaps the best way t o describe deed restrictions is
t o demonstrate how they work: The owner of a tract of
land wants to subdivide it into building lots and sell them.
I f the owner o f the tract i s also a builder, he wants to
sell you a house with the lot. I t is naturally his desire t o
get as high a price as possible for his lots, and i t is
therefore in his interest to impress you with the desirability of living in his development. He wants t o convince you that the area is definitely high-grade, and will,
furthermore, remain that way and not deteriorate. He
drafts a "Declaration of Restrictions." This document
generally describes the type of house, garage, etc., you
may erect on the property, the minimum setback, type
of fence, and other items. The developer submits his plat
and restrictions to the local zoning commission or other
cognizant authority, and if they comply with local planning and zoning laws, they are approved and recorded.
The deed to your property will probably say "Subject t o
any restrictions of record" or something similar. The
restrictions are now legal.
Anyone who buys property in this subdivision is, in
effect, signing a contract to abide by these restrictions,
and if he violates them he can be sued by any property
owner or group of property owners in the subdivision.
Of course, there is no certainty that you will be sued
if you violate the restrictions. But you are certainly subject t o lawsuits. If the development is new, the developer
himself may sue, since he may feel that the presence of a
70-foot tower makes i t more difficult for him t o sell his
remaining lots. But even after the subdivision is all sold
out, at which time the original developer rapidly loses
interest in the character of the neighborhood, any property owner can sue if he finds your tower objectionable,
and, depending on the exact wording of the restrictions,
would probably have a good chance of winning. The
result would be a court order for you to remove your
tower.
In my search for a lot, I accumulated quite a collection of sets of restrictions. Every one of them, t o a
greater or lesser degree, implied restrictions on the erection of antennas although the wording varied. In fact,
most of them made no mention of antennas as such.
These specified in detail what youcould put on the property - and an amateur antenna was n o t one of the permitted things. Typical wording was, "No structure other
Harry R. Hyder, W71V, 9842 North 57th Street,
Phoenix, Arizona 85253
...
than a single-family dwelling
garage, swimming pool,
etc . shall be erected or permitted t o remain on this
property.
One local amateur was sued by a developer for violation of a restriction like that. He won his case because
his tower was mounted on top of his carport, and the
court ruled i t was part of the house and not a separate
structure. Presumably if the tower has been mounted on
the ground apart from his house, he might have lost.
This victory cost the ham $2500 in legal fees. Some
victory.
Other restrictions specify a maximum height above
ground or roof level that no structure can exceed; 35
feet (1 1 meters) above ground level or 3 feet (1 meter)
above roof level are common values.
Some restrictions do mention antennas. One actually
specifically permitted amateur radio antennas but said
that the towers must be of the retractable type and
lowered when not in use. One planned community in the
Phoenix area bans all outdoor antennas including TV
antennas (this community has a master antenna and
cable distribution system).
Another common type of restriction states that anything erected on the property must be approved by the
"Architectural Committee" of the development.
When considering lots, I always asked the agent whether
there were any restrictions on the erection of amateur
antennas, and was usually assured that there were none.
This frequently turned out to be not quite true. Very
rarely, in fact, did the agent have a knowledge of what
the restrictions actually said. Ask the agent t o get a copy
of the restrictions, which he can easily do, and read
them yourself. You can get copies yourself as most of
the large title insurance companies have this information
on file. Alternately, you can get copies at the County
Recorder's office (to be valid, the restrictions must be a
matter of record).
All of this sounds pretty discouraging, but there are
subdivisions that do not have any restrictions. This is
. .
The restrictive covenants, zoning ordinances and b u i l d i n g
codes w h i c h affect amateur radio antennas vary w i d e l y
f r o m one locale t o another, and m u c h o f the law is case
law which varies greatly f r o m state t o state. Some states,
f o r example, have given substantial weight t o aesthetics
w h i l e other states have held t h a t aesthetics cannot be considered at all. A n d , although t h e law o n restrictive covenents is much m o r e u n i f o r m f r o m state t o state, there are
c o n f l i c t i n g opinions i n amateur r a d i o cases. Furthermore,
t h e application o f c o m m o n and statutory laws o n nuisances is a rather new development w h i c h is certain t o
become more o f a p r o b l e m i n t h e years ahead.
T h i s article is based o n the author's experiences i n t h e
Phoenix, Arizona, area, so the restrictive covenants, zoning ordinances and b u i l d i n g codes may be considerably
d i f f e r e n t then i n y o u r o w n area. Nevertheless, his basic
guidelines are applicable i n practically every case. F o l l o w ing these guidelines m a y n o t keep y o u completely o u t o f
t r o u b l e (witness t h e nuisance cases o f W P M V N and
WPOVC), b u t t h e y should give y o u a f o o t u p o n t h e
problem.
Editor
more likely t o be true of older areas since it has been
only relatively recently that restrictions of this sort have
become widespread. There are also many odd pieces of
property that have never been part of subdivisions. If
you look hard enough, you can find a suitable house or
lot that has no restrictions.
I n any event, you should have your attorney insert a
clause in the sales contract that your money will be
returned if any restrictions on the erection of ham antennas are found t o exist.
zoning ordinances
Unlike deed restrictions, which are in the nature of
private contracts, zoning regulations are a matter of law.
Zoning is an attempt by a municipality or county to
control the usage of land within its boundaries for the
purpose of orderly growth and development. Sections of
the incorporated area are designated residential, commercial, industrial, etc., and within these classifications
are sub-classifications.
The various types of residential zoning control the
number of residences per acre, whether single-family or
apartment buildings, maximum height, setback from the
street and property line, street and utility easements,
and similar matters. Depending on the exact wording,
zoning regulations can imply prohibition of the erection
of antenna towers, or can expressly forbid them. Some
even expressly permit them. The zoning regulations of
Scottsdale, Arizona, for example, specifically permit antenna towers up t o 70 feet (21 meters).
In contrast, Paradise Valley, a bedroom community
adjoining Phoenix, forbids all towers. An amusing sidelight t o this is that Paradise Valley's most distinguished
citizen is Senator Barry Godlwater, K7UGA. Senator
Goldwater's home is equipped with two tall towers
mounting quite an array of beams, including a very impressive log-periodic.
The Phoenix Zoning Ordinance controls building
height, but a paragraph specifically excludes antennas,
flagpoles, water towers, etc., from the height restrictions.
In general, amateurs are in less danger from zoning
ordinances than from deed restrictions. One reason is the
natural slowness of democratic governments t o react except in the face of political pressure. Another is the fact
that most municipal or county attorney's offices are
very understaffed, and are not anxious t o undertake
such suits, which do not have the glamour of, say, criminal prosecutions. Nevertheless, city and county attorneys are usually elected officials, and if one of your
neighbors objects to your antenna, and he is politically
well-connected, you could be in for trouble.
The amateur does have one thing going for him.
There seems t o be an unofficial legal principle that says
what others have done in the past without legal interference, you can do too. If there are a number of amateurs in your city who have towers and have never been
threatened with legal action, regardless of the exact
wording of the zoning regulations, you are probably on
safe ground.
january 1976
25
In any event, it is a good idea to become familiar with
your local zoning regulations. These can be obtained
from your local planning and zoning commission, usually located at city hall or nearby. The complete Phoenix
Zoning Ordinance, a sizable book, costs $5.00, and by
paying an additional $5.00, you can be placed permanently on the mailing list for changes and additions.
Other cities probably have similar arrangements.
building codes
Building codes are designed to protect the health and
safety of the citizens of a political division. Antenna
towers come into this because an improperly designed or
installed tower could collapse and cause damage to life
or property. I have personally seen antennas that seemed
to stay up by sheer faith, and it seems reasonable that
anyone erecting a tower should be able to demonstrate
that it will not be a hazard to himself or his neighbors.
Relatively few amateurs apply for building permits
for towers. I strongly recommend it. In principle, at
least, if you do not get a permit with its attendant inspections, you could be forced to take your tower down.
It's difficult to say just how likely this is to happen as i t
i s highly dependent on your local administration, but i t
can and has happened. In any event a building permit is
a nice piece of insurance against that possibility.
In some localities obtaining a building permit is mere
formality. Some areas even have special provisions in
their local codes for amateur radio towers. In others it is
more difficult. A typical requirement would be a set of
plans and stress calculations approved by a registered
professional engineer. First find out from your local
building inspection department what is required, and
then attempt to supply it.
One problem that you may run into is that the personnel in your local inspection department have never
been asked to issue a permit for a tower before, and like
true bureaucrats, assume that since they have never done
it before, it must be illegal. Don't stop there.
An experience of mine is enlightening. When I was
interested in buying a piece of property in a local community, I went t o the inspection office and asked the
man behind the counter how to apply for a permit for a
50-foot (15-meter) antenna tower. He informed me very
positively that such a tower was not permitted and he
could not issue me a permit. I then asked him why the
local zoning ordinances permitted antenna towers up to
70 feet (21 meters) if they were illegal (I had already
checked this). I then showed him the wording of the
ordinance, and he confessed that he had never seen that
paragraph. He allowed as how he probably could issue a
permit, but would have to check with the city engineer
about the actual requirements. I did not pursue the
matter a t that time, and I eventually bought my lot
elsewhere, but an amateur friend of mine subsequently
received a permit for a 60-foot (18-meter) tower from
the same office merely by supplying a set of the tower
manufacturer's plans and specifications.
Don't stop at the first "No." Building inspection
departments are bound by law and cannot act arbitrarily. If the zoning laws do not prohibit towers and if
you can demonstrate that the tower design and installation are sound, they are bound to issue you a permit.
The cost is usually about five dollars.
It would be a good idea to read the sections of your
local building code dealing with towers. You can do this
at the inspection office. If you run into any problems it
would be a good idea to request a personal talk with the
city or county engineer. They are usually pretty
reasonable.
In the city of Phoenix the law requires that the tower
stress calculations be checked by a registered professional engineer in the State of Arizona and that he supply a letter saying that he has done this, duly stamped
with his seal. I don't know how widespread this requirement is, but i t could mean a fee of $50 or more. In my
own case, the tower I was planning to erect had already
been approved for a previous applicant. Some areas have
approvals for specific makes and models of towers on
record; this constitutes a sort of type acceptance. It
would be a good idea to find out which types have previously been approved, and if one of these suits your
requirements, getting a permit should present no problems.
Another thing to do is to find a local amateur who has
successfully obtained a building permit and find out
what procedure he followed. When dealing with the law,
precedent is highly important.
conclusions
Bi3-+wlc
"They're recalling your outside antenna."
While it may be troublesome and frustrating to run
the gauntlet of deed restrictions, zoning ordinances and
building permits, i t can be done - the most important
ingredient i s persistance and it is worth it. Amateurs
have been ordered by the courts to remove their antennas for violation of all of these, and it gives you a
comfortable feeling to know that you are completely
protected.
ham radio
More Details? CHECK-OFF Page 102
january 1976
27
diode detectors
I
I
A comparison of the
operating characteristics of
various diode detectors
and how they
can be improved
through modern circuitry
I
I
I
I
II
I
From the earliest days of radio the subject that received
the most attention of radio amateurs (first unlicensed,
and later with amateur calls) was the detector. The
antenna-ground system, although it allowed for a good
deal of innovation, was generally size-limited by the
amateur's real estate or by the basic laws of physics.
Also, antennas are fun t o work on only in decent
weather; little antenna work is done during the winter
months. The transmitter was also straightforward: you
simply bought as large a transformer as you could
a f f o r d . The spark gap and its coupling t o the
antenna-ground system were relatively simple.
The detector, however, didn't cost much and could
be worked on at any time so thousands of experimenters
tinkered away their winter evenings trying t o improve
their detectors. Eventually they had enough success that
the detectors became known as "receivers." Another
nice feature of experimenting with detectors was that
you could receive signals t o "get a foot in the door" of
radio, even i f you had no transmitter. All sorts of devices
were tried by these early experimenters: flame ionization detectors, coherers, electrolytic detectors, thermoelectric detectors, magnetic hysteresis detectors, crystal
detectors and the early Fleming valve (vacuum diode).
Of all the early detectors the crystal type received the
most widespread usage and "crystal set" eventually be-
28
january 1976
I
came a household word. Various types of mineral and
man-made crystals such as galena, silicon, perikon
(copper pyrites and zincitel, molybdenite and carborundum were used. Fig. 1 shows a simple crystal set using
one of the crystals of the period. This same circuit could
still be used today, but a modern signal diode would be
used in place of the crystal and catwhisker.
Galena (lead sulphide), an important lead ore found
here and in Europe, was the most popular of the crystals
used in the early days of radio because i t was the most
sensitive. Steel galena, so called because i t resembles a
piece of broken steel rod, contains a small percentage of
silver and, although not quite as sensitive as plain galena,
became popular jn later years because it was somewhat
easier to adjust.
The crystals used as radio detectors were mounted in
clips, held in tin-foil cups, floated in mercury, or more
commonly, mounted in a small "pill" of a low-meltingpoint alloy. (Some experimenters who tried t o mold
their own crystal holders used a too-hot mixture of lead,
only t o discover that the heat destroyed the sensitivity
of the galena.) The catwhisker, a length of fine, stiff
wire," was moved about the surface of the crystal until
an "active" spot was found. This metal-to-semicon-
Y
ANTENNA
P R ~ M A R Y ~? E c o N o f i R Y .
1
fig. 1. Simple crystal set
typical of those used in the
early days of radio.
'Different types of crystals require different catwhiskers. Galena, for example requires a stiff, clean catwhisker with very
little pressure. Plated copper is best, with brass and platinum
running a close second. If you use a steel galena crystal, however,
a German-silver catwhisker is best. For silicon crystals, tungsten
catwhiskers are preferred although molydenum is sometimes
used. Chromium or steel are recommended as catwhiskers for
carborundum crystals (which also require a bias battery), while
many different metals have been used successfully with molybdenitecrystals.
Hank Olson, WGGXN, Post Office Box 339, Menlo
Park, California 94025
ductor interface is similar in many ways to the pointcontact diodes of today. A typical galena-catwhisker
assembly is shown in fig. 2.
The success of the vacuum tube, first as a diode
(Fleming valve) and later as a triode (Deforest Audion)
eclipsed the crystal detector commercially after about
1921. Crystal sets continued to be used by experimenters, however, as they still are today. Also, work
continued in the laboratory on silicon crystal detectors
as power detectors for microwave measurements.' This
laboratory experimentation was greatly refined and expanded during World War II as engineers tried to solve
the microwave radar mixer problem. This concentrated
research effort on crystal detectors eventually led to a
huge body of knowledge on basic silicon and germanium
crystal physics and how various impurities affect the
semiconducting properties of these materials.
fig. 2. Commercial galena-catwhisker assembly. These units can
still be obtained at some radio distributors..
immediately became popular with experimenters, and
started showing up in everything from absorption wavemeters to a-m speech clipper^.^
The alloyed-junction silicon and germanium diodes
came along in the early 1 9 5 0 ~ . The
~ . ~ germanium junction diode achieved some degree of popularity as a rectifier (1N91 - 1N93) but i s considered obsolete today
while the silicon junction diode came into its own both
as a signal diode and power rectifier. An example of an
early alloy-junction rectifier i s the 1N536-IN540 family;
the 1N482-IN485 family are typical early alloy-junction
signal diodes.
I-F
Steel galena crystal offered to amateurs in the 1920s.
The high-inverse voltage germanium point-contact
diode came directly out of these wartime research
efforts, and most of the other semiconductor develop
ments we know today came indirectly from this same
research. The twenty-eight volume MIT Radiation
Laboratory Series includes one whole volume which describes the semiconductor diode developments for radar
usage which occurred during this period.'
Based upon the research done during the war, germanium pointcontact diodes became available to industry in the late 1940s. The 1N34 was offered by Sylvania,
'Mounted galena crystals, crystal stands and catwhisker assernblies are available from Modern Radio Laboratories, Post Box
1477, Garden Grove, California 92642. Their catalog, available
for 25d, also lists an assortment of crystal-set kits and other
hard-to-find items such as carborundurn detectors and coil
sliders.
OUTWT
0 DOUBLE- BALANCED MIXER
"T-]ilh
+p
OSCILLATOR
I - F OUTPUT
0 SINGLE-BALANCED MIXER
@ BrnDBAND
DOUBLER
fig. 3. Three diode circuits which use Schottky diodes. Shown in
(A) is a typical double-balanced mixer. A single-balanced mixer
is shown i n (B) while (C) shows a broadband doubler circuit.
january 1976
29
While most modern silicon junction rectifiers are still
made by the alloy process (1N4001-1N4007, for
example), newer silicon junction signal diodes are usually made by the planar epitaxial process (lN4454, for
example). If you insist on a germanium junction signal
diode, the base-emitter elements of a germanium junction transistor (2N404 or 2N5043) could be used.
There have been many other types of diodes developed since the silicon and germanium types discussed
above. Tunnel, PIN, step-recovery, varactor, Zener,
Virtually all Schottky diodes are silicon types, and
their advantage over point-contact types i s that their
characteristics are closely matched and stable. This stability quality is quite important because i t allows the
close matching of diode pairs or quads which make it
possible to build really good double-balanced mixers.
The double-balanced mixer and its related singlebalanced mixer and broadband doubler have made an
enormous impact on modern vhf, uhf, and microwave
systems.
24
22
4
5
20
1s
C
2 16
$
U
2
0
$
14
12
im
10
8
0
FORWARD VOLTAGE
0
1
3
4
5
6
FORWARD VOLTAGE
0 CARBORUNDUM
GALENA 8 PERIKON
FORWARD VOLTAGE
IN270 GERMANIUM POINT CONTACT
2
FORWARD VOLTAGE
@
IN914 SILICON ALLOY JUNCTION
fig. 4. Forward conduction characteristics of several different diode types including galena and perikon (A),
carborundum (B), germanium point contact ( C ) and silicon alloy junction (Dl.
Gunn, IMPATT and TRAPATT are some of these special
types, but are not, in general, used as detectors of the
common, rectifying type.
One newer type of diode, the Schottky-barrier or hotcarrier diode, has characteristics similar t o the pointcontact device. Like the point-contact diode, the
Schottky diode uses a metal-semiconductor junction; in
the Schottky diode, however, the metal is deposited on
the semiconductor by sputtering in a vacuum. Examples
o f t h e Schottky diode are the Hewlett Packard
5082-2800 and the Motorola MBD5Ol .
30
january 1976
Three basic diode circuits which use matched
Schottky diodes are shown in fig. 3. Note that the transformers in fig. 3 are usually built with a few turns of
wire on ferrite toroids, so the circuits are often useful
over a three-decade frequency range (200 kHz t o 200
MHz is common).
The forward conduction characteristics presented in
fig. 4 will give you an idea how some of the various
semiconductor diodes compare. The curves in fig. 4A for
galena and perikon are from reference 6, the carborundurn curve (fig. 48) is from reference 7, while the for-
ward characteristics for the 1N270 (fig. 4C) and 1N914
(fig. 4D) were taken from the data sheets of currently
manufactured diodes. As can be seen, the forward current characteristic of any diode semiconductor diode is
far from linear.
diode detectors
fig. 5. Basic dlode detectors showing simple
reslstive load ( A ) and
more usual case where a
capacitor is placed In
parallel wlth the load
resistor (8).
DIODE
@
RESISTIVE LOAD
An early article by Colebrook exhaustively describes
crystal rectifiers and their use as detectors of radio
OlOOE
E
.,"w
0 R-C
Crystal recelver of the type used b y amateurs sixty years ago.
Station was tuned i n b y moving the slider along the tuning coil.
Selectivity was very poor, but there were few stations on the air
and a local spark transmitter wiped out the DX anyway.
signak6 Although the author had only early galena and
perikon diodes t o work with, his mathematical analysis
and conclusions are as fresh today as they were when
written in 1925. The basic diode detector shown in fig. 5
is the same as that used in reference 6.
Fig. 5A shows a resistive load while fig. 5B shows the
more usual case where there is a capacitor in parallel
with the load resistor (this increased detector efficiency). The capacitor should present a low impedance
at the carrier frequency (as compared t o resistor R ) , and
a high impedance at the modulation frequencies. In the
circuit of fig. 1 a 0.002 pF capacitor is placed in parallel
with a set of 2000-ohm headphones. At 1 MHz (the
center of the broadcast band, for which this crystal set
LOAD
was designed) a 0.002 pF capacitor has about 80 ohms
reactance. At 1000 Hz, a typical audio t e s t frequency,
the reactance of this same capacitor is nearly 80 kilohms.
The circuit shown in fig. 6 was built to demonstrate
how a shunt capacitor increases efficiency, and also to
show how several common diode types compare. The
51-ohm resistor at the input simply terminates the
amplitude-modulated signal generator. The LM318H IC
and associated capacitors and resistors comprise a lowpass filter with a cutoff frequency at 2080 Hz. In this circuit the 2200-ohm resistor, R1, is the detector load and
the 510-ohm resistor a t the output of U1 is to prevent oscillation of the op amp when using a length of coax to the
vtvm. The 0.002 pF capacitor can be switched in or out;
the results are shown in fig. 7. For higher input signal
levels the capacitor increases the output audio voltage
level by 8 to 10 dB (enhancement with the 6AL5 vacuum tube diode is even more marked at some input
levels).
Note that since the plots of input rf level vs audio
output level presented in fig. 7 are on log-log coordinates
(since the abscissa and ordinate are both in dB) two
straight lines may be drawn on the plots, one representing a linear relation and the other a square-law relation.
For large input signals, say above -20 dBm, all the detectors approach a linear slope. It should also be noted that
DETECTOR
ACTIVE LDWPASS FILTER
f, : 2 kHz
fig. 6. Circuit for testing the operation of various diode detectors. Test results are plotted in fig. 7.
january 1976
31
+5
0
-I0
0
0
g
-20
E
B
k- - 3 0
3
C
3
0
-40
-50
-20
-10
0
+I0
+2 0
INPUT, dBm 150 ohms)
INPUT, dBm 150 ohms)
0 IN270 GERMANIUM DIODE
I N 4 4 5 4 SILICON JUNCTION DIODE
5
0
-3
lo
0
g
S
20
k-
30
3
E
0
40
50
20
I0
0
10
20
-2 0
- 10
INPUT, dBm 150 ohms)
@
IN82 SILICON DIODE
0
+ 10
INPUT, dBm 150 ohms)
@ IN34,
GERMANIUM POINT-CONTACT DIODE
fig. 7. R f input level vs audio output level for various types of diodes, with and
without parallel load capacitor. Linear and square-law references are shown for comparison.
at input levels below -20 dBm a square-law or larger
exponent relationship is usual. The point is that although some diodes are more nearly linear over a larger
range of input voltage than others, none of them could
remotely be considered as linear detectors at input signal
levels below -20 dBm. A 6AL5 detector circuit with
capacitor, comes closest, perhaps, t o the textbook
explanation that "diodes are square-law devices for small
signals and linear devices for larger signals."
fig. 9. Precision half-wave detector using semiconductor diodes
and an operational amplifier.
MODULATOR
SIGNAL
LIMITER
FILTER
VOLTAGECONTROLLED
PHASE-SHIFT
NETWORK
FILTER
fig. 8. Using a phase-locked loop as an a-m detector
(see text).
32
januaty 1976
I n a receiver, operation of the diode detector in its
square-law region means that for every 10 dB weaker a
signal may be, the output is 20 dB down. This i s clearly
not a good way t o operate. Not only does i t waste stage
gain, i t also degrades the signal-to-noise ratio. To avoid
the square-law region most receivers use enough rf and
i-f gain to keep the input voltage level t o the diode
detector up in the region where i t behaves linearly. Unless agc i s used this usually means that the last i-f amplifier must be a small transmitting tube or other largesignal device i f reasonable dynamic range i s t o be
achieved.
INPUT, dBm (50 ohms)
INPUT, dBm (50 ohms)
@ GALENA-CATSWHISKER
H-P 5 0 8 2 - 2 8 0 0 SCHOTTKY DIODE
The product detector does not make a very satisfactory detector for a-m because the bfo never quite
matches the receiver carrier frequency. This results in a
beat note being present in the audio output unless a
phase-locked loop is used to synchronize the bfo to the
OP A M P
INPUT, dBm (50 ohms)
@ 6AL5
VACUUM DIODE
fig. 1 1. Improved version of the full-wave detector provides better linearity than previous circuits.
R
R
R
::
INPUT
RF
received carrier frequency. This phase-locked loop form
of a-m detection i s shown in fig. 8; with the modern
phase-locked loop ICs that are now available the circuit
is not unreasonably complex.
Another technique for linearizing an a-m detector involves the use of an operational amplifier. Although this
fig. 10. Precision full-wave detector using semiconductor diodes
and two operational amplifiers.
linear diode detectors
Few commercial receivers bother with such luxuries
as large-signal capability in the last i-f stage - they either
rely on agc or accept detector non-linearity. Fortunately, the modern extensive use of ssb on the highfrequency bands has forced receiver manufacturers to
use the inherently more linear product detector. The
linearity of product detectors, which are essentially
mixers with an audio output, is due to the fact that the
oscillators which drive them completely control the conduction of the nonlinear devices used as mixers.
lo H Z
loo
HI
Ih m
lo k H z 100 k H z
1 MHz
10 M H z 100
MHz
FREQUENCY
fig. 12. Open-loop gain vs frequency of
LM318H operational amplifier IC.
the
january 1976
33
technique has been around for quite some time, i t has
only recently become practical with the availability of
low cost, high-frequency IC op amp^.^^^ Fig. 9 shows
the basic precision diode detector using an op amp. Fig.
10 shows a full-wave version of the detector (from reference 9). The full-wave version has the disadvantage that
the delay for positive input signals, which are inverted
and amplified two times, i s twice that for composite
signals. Because of the delay difference, the signals don't
subtract in phase, so high-frequency performance suffers. Fig. 11 shows a precision full-wave diode detector,
attributed to Dr. Nick Cianos of SRI, that solves the
problem.
DETECTOR
only expect about 24 dB improvement in linearity at 1
MHz. To check this I built the circuit shown in fig. 13.
The test results are plotted in fig. 14. The improvement
at low input signal level linearity is quite apparent. The
principle of op ampldiode detection is used in the
National LM372, an IC that combines the functions o f
i-f amplifier and a-m detector.
summary
The diode detector has been the standard a-m detector almost since radio began. Today we essentially have
only two choices of semiconductor material: germanium
and silicon. Germanium has lower offset voltage while
LOWPASS FILTER
RF
INPUT
VTVM
f i g . 13. Test setup for
checking the improved fullwave detector circuit
shown in fig. 11. Inputoutput characteristics are
extremely linear as shown
i n fig. 14.
Diode detectors which use an op amp in the circuit
reduce the input voltage at which the transfer curve (input t o output relation) becomes non-linear by a factor
equal to the open-loop gain of the op amp. Since op amp
voltage gains can be more than 100 dB at the lower
frequencies this can make a significant difference in
detector performance.
The performance curve of a good monolithic IC op
amp (National LM318H) i s shown in fig. 12. Note that the
open-loop gain drops as frequency increases so you can
+5
0
n
-10
f
<
0
g
4
&-
-20
-30
2
C
-40
-50
-20
-I 0
0
+ 10
+PO
INPUT, dBm (50 ohms)
fig. 14. Input-output characteristics of the improved full-wave
detector circuit shown in fig. 1 3 coincides very closely t o linear
191 january
references
1. G . Southworth and A . King, "Metal Horns as Directive Receivers of Ultra-Short Waves," Proceedings of the I R E , number
27, 1939, page 95.
2 . H . Torrey and C. Whitrner, "Crystal Rectifiers," Volume 15,
Massachusetts Institute of Technology Radiation Laboratory
Series, McGraw-Hill, New York, 1948.
3 . "Electronic Shortcuts for Hobbyists, 24 Simplified Crystal
Diode Applications," Second Edition, Sylvania Electric. 1951.
4. W. Pietenpol, "PN Junction Rectifier and Photo Cell," Physics Review, April, 1951, page 120.
5. G. Pearson and B. Sawyer, "Silicon P-N Junction Alloy
Diodes," Proceedings of the I R E , November, 1952, page 1348.
6 . F . Colebrook, "The Rectifying Detector," The Wireless
Engineer, March, 1925, page 330; April, 1925, page 396; May,
1925, page 459.
7. A. Ghirardi, Radio Physics Course, Radio & Technical Publishing Co., New York, 1931, page 380.
8 . Handbook of Operational Amplifier Applications, First
Edition, Burr-Brown Research Corporation, Tucson, Arizona,
1963, page 70.
9 . G . Gi les, Fairchild Semiconductor Linear Integrated Circuits
Applications Handbook, Fairchild Semiconductor, 1967, page
148.
1 0 "Linear Applications," Applications Note A N 15-5, National
Semiconductor, February, 1973.
ham radio
reference.
34
silicon has the benefit of improved technological processing. A semiconductor diode of either type, used in
combination with a modern IC op amp, can greatly improve the linear dynamic range of the detector. When
used as an integral part of an I C the silicon diode holds
great promise in the future.
1976
I TRANSISTOR
Cr
is& type. 3 to 20 MHz, OX-LO,
Cat. NO. 035100. 20 to 60 MHZ,
OX-Hi, Cat. No. 035101
Specify when ordering.
Price $3.95 ea.
A single tuned circuit intended
for signal conversion i n the
30 t o 170 MHz range. Harm o n i c s o f t h e OX o r OF-1
oscillator are used for injection
in the 60 to 179 MHz range.
3 to 20 MHz, Lo Kit, Cat. No.
035105. 20 to 170 MHz, Hi Kit,
Cat. No. 035106
A single tuned output amplifier
designed to follow the OX or
OF-1 oscillator. Outputs up to
200 mw, depending o n
frequency and voltage. Amplifiercan be amplitude modulated.
3 to 30 MHz, Cat. No. 035104
Specify when ordering.
Price $4.75 ea.
Specify when ordering.
Price. $4.50 ea.
OF-1 OSCILLATOR
Crystal c o n t r o l l e d transistor type. 3 to 20 MHz, OF-1,
Lo, Cat. No. 035108. 20 to 60
MHz, OF-1, Hi, Cat. No. 035109
Specify when order~ng.
Price $3.25 ea.
031081
General p u r p o s e a m p l i f i e r
which may be used as a tuned
o r u n t u n e d u n i t i n RF a n d
audio applications. 20 Hz to
150 MHz with 6 to 30 db gain.
Cat. No. 035107
Specify when Ordering
Price $4.75 ea.
Specifica
3 to 20 MHz - For
use i n OX OSC Lo
Specify when ordering.
Specify when ordering
Shipping and postage (inside U.S.. Canada and Mexico only) will be prepaid by
International. Prices quoted for U.S.. Canada and Mexico orders only. Orders
for shipment to other countries will be quoted on request. Address orders to:
M/S Dept., P.O. Box 32497, Oklahoma City. Oklahoma 73132.
$4.95 ea.
20 to 60 MHz - For
use in OX OSC Hi
Specify when ordering
031300
SAX-1
TRANSISTO
RF AMP
A small s i g n a l a m p l i f i e r t o
drive the MXX-1 Mixer. Signal
tuned input and link output.
3 to 20 MHz. Lo Kit. Cat. No.
035102. 20 to 170 MHz, Hi Kit,
Cat. No. 035103
EX CRYSTALS
(HC 6 l U HOLDER)
Cat. No.
031080
BAX-1
BROADBAND AMP
$4.95 ea.
3 to 20 MHz - For
use i n OF-1L OSC
Price $4.50 ea.
-
--
Specify when ordering
031310
$4.25 ea.
20 to 60 MHz - For
use i n OF-1 H OSC
Specify when ordering.
$4.25 ea.
More Details? CHECK-OFF Page 102
International Crystal Mfg. Co., Inc.
10 North Lee
Oklahoma City, Oklahoma 73102
january 1976
35
believe that i t would be fun t o jump into the middle of
the one that i s occurring at this moment and closely
observe events that will have a profound influence on
electronic measurement, laboratory instrumentation and
amateur station control. Therefore, over the next few
months this column will be devoted t o the subject of
microcomputers: what they are, how they operate, and
what they can and cannot do for the electronic experimenter, engineer or laboratory scientist.
We shall use microprocessor operation and interfacing
as a vehicle to probe more deeply into the detailed concepts and techniques of computer interfacing. Please
keep in mind that the microprocessor, when complemented by memory, buffers, and inputfoutput (110)
devices, is as much a computer as i t s larger and usually
faster rivals, the minicomputers and full-size computers.
By learning how t o interface a microprocessor, you will
simultaneously learn the concepts of how to interface a
minicomputer or full size computer. The use of interrupts, device selects, software generated strobes, timing
loops, and the like are common to all.
To gain full value from some of our forthcoming
columns, it would be beneficial t o have an understanding
of the basic principles of digital electronics. Some very
important terms and concepts that you should master
include the following: gate, logic element, counter, gated
counter, monostable, enable, disable, inhibit, strobe,
decoder, multiplexer, demultiplexer, timer, clock pulse,
A discussion of
m i c r ~ p r ~ c e ~ ~ ~ r ~
and how they fit
into the scheme
of computers
and controllers
that exist today
By now, most amateurs are aware of the fact that a
revolution is occurring in the electronics industry:
microprocessors. If you had held stock i n companies
that manufacture microprocessors, this fact would have
become quite apparent after RCA's misinterpreted
announcement several months ago that microprocessors
will soon be incorporated into U.S. automobiles. Rather
than rehash an electronics revolution after i t i s over, we
36
january 1976
By Dzvid G. Larsen, WB4HYJ, Peter R. Rony and
Jonathan A. Titus.
Mr. Larsen, Department of Chemistry, and Dr. Rony, Department of
Chemical Engineering, are with the Virginia Polytechnic Institute and
State University, Blacksburg, Virginia. Mr. Jonathan Titus is President
of Tychon Inc., Blacksburg, Virginia.
positive edge, negative edge, flip-flop, latch, bus, TriStateTM, shift register, dynamic RAM, static RAM,
ROM, programmable ROM, upldown counter, AND,
OR, NAND, NOR, exclusive OR, arithmetic element,
and more. Our pair of books on digital electronics, Bugbooks I and 11. Logic & Memory Experiments Using TTL
Integrated Circuits, will bring you t o the level of understanding in digital electronics required t o interface
microcomputers; other digital books, such as the pair
marketed by Hewlett-Packard in conjunction with their
logic lab, will also help you develop the skills that you
will need. Digital electronics is a rapidly expanding field,
and new texts and reference manuals are appearing at
the rate of one every several weeks.
As we currently envision them, future columns will
offer a tutorial on the operation and interfacing of a
very popular microprocessor, the lntel 8080 &bit microprocessor, which can perform a simple logic or arithmetic instruction in only 2psec and can directly address
65,536 different memory locations, each containing
eight bits of data. Originally priced at $360 in quantities
of one, you can purchase an 8080 now for about $50
from selected supply sources and its cost will be no more
than $5 two or three years from today. The 8080 has
some important rivals, e.g., the Motorola 6800 and the
Fairchild F8, but i t is a worthy selection nevertheless.
Each microprocessor has its special features. However,
the general concepts developed in this column will be
applicable t o any microcomputer system.
Standing alone, a microprocessor chip can do nothing. It functions only in the context of a microcomputer
system, in which appropriate integrated-circuit chips are
incorporated to complement the basic function of the
microprocessor (pP): to serve as a central processing unit
(CPU) in which logic and arithmetic operations and data
transfers between register, memory, and the outside
world are performed. In some columns, we will need to
focus upon a specific microcomputer system. For this
purpose, we have chosen a new system that is specially
designed to instruct individuals in all of the details of
microprocessor operation and interfacing: the Mark 80
microcomputer (fig. 1). This particular system, shown
with 4k of solid-state memory and a control panel, is
built around the lntel 8080 microprocessor chip. Except
for a power supply, i t is completely operational. The
system is bus structured and has all important inputs and
outputs connected to a solderless breadboarding socket,
permitting interfacing concepts to be learned, tested,
and breadboarded into a digital circuit of your own
design.
Material presented here is reprinted with permission from
American Laboratory. "What's next? Microprocessors,"
American Laboratory, July, 1975; "Microprocessors:
Where do they fit?" American Laboratory, 1975; "The
anatomy of a microcomputer," American Laboratory,
September, 1975; copyright O International Scientific
Communications, Inc., Fairfield, Connecticut, 1975.
microprocessors: where do they fit?
We would first like to discuss what a microprocessor
i s and how i t fits into the general scheme of computers
and controllers that exist today. Eadie, in his book,
Introduction to the Basic Computer, has defined the
term data processor as "a digital device that processes
data. It may be a computer, but in a larger sense it may
gather, distribute, digest, analyze, and perform other
organization or smoothing operations on data. These
operations, then, are not necessarily computational.
Data processor is a more inclusive term than comp~ter."~
A microprocessor i s a single integrated-circuit chip
that contains a t least 75 percent of the power of a cornputer. I t usually cannot do anything without the aid of
support chips and memory, however, and therefore can
be distinguished from a microcomputer, which is a full
operational system based upon a microprocessor chip
that contains memory, latches, counters, input/output
devices, buffers, and a power supply in addition to the
microprocessor chip. A microcomputer may be a "black
box" with only a single switch: operate/reset. The 8080
microprocessor, a 40-pin LSI chip, is shown in fig. 2. A
typical system based upon this chip is shown in fig. 3;
the 8080 chip i s located on the CPU board on the left.
A microcomputer possesses all of the minimum
requirements of a computer. For example:
It can input and output data, which i s usually in
the form of digital electronic signals. Common I/O
devices include teleprinters, CRT displays, paper
fig. 1. The Mark 80 microcomputer system.
b
january 1976
37
tape readers, floppy disks, magnetic tapes, cassette
tapes, laboratory instruments, and process control
devices.
It contains an arithmeticllogic unit (ALU) that can
perform arithmetic andlor logic operations such as
add, subtract, compare, rotate left, rotate right,
AND, OR, negation, and exclusive OR.
It contains a minimum amount of "fast" memory
such as RAM, ROM, PROM, or core, but usually
not cards or paper tape, in which data and program instructions are stored. The data and instructions are stored as 4-bit, &bit, 12-bit, or. 16-bit
words.
It is programmable. The data and program instructions can be arranged in any sequence desired, in
contrast to the programmable calculator, in which
the precise manner that a keyboard function is
executed cannot be changed by the operator.
It is fast, with an ability t o execute a simple
instruction in ten microseconds or less. All existing
microcomputers are digital and TTL compatible,
where logic 0 corresponds to ground potential and
logic 1 corresponds to +5 volts.
There appears to be some misunderstanding concerning the role of current microprocessors and microcomputers relative to other types of computers. The
temptation i s great to order a modest microcomputer
system and then to surround it with $5000 worth of I10
devices such as floppy disks and line printers. At this
point we would like to provide a bit of insight concerning the most likely role of microcomputers. Fig. 4
graphically depicts where microcomputer applications fit
today, and table 1, taken from an article by Riley,2
depicts the spectrum of computer-equipment compl ex it y from simple hard-wired systems to highperformance general data processing equipment.
Microprocessor and microcomputer applications fall
between relay logic and discrete random logic (gates and
flip-flops) on one hand and small minicomputers such as
the PDP 8A and the LSI 11 on the other. Microcomputers built from microprocessor chips are not as sophisticated as some of the popular minicomputers and cannot easily perform certain types of data processing problems. They are simply not set up at this time to run
fig. 3. A typical microcomputer system. Shown on the left is the
central processing unit (CPU), which consists of input/output
buffer chips and miscellaneous control logic. Shown on the right
is the microcomputer memory, in this case l k of R A M and 2 5 6
words of ROM. Decoder chips permit the memory to be located
anywhere within 65k of microprocessor addressable memory.
FORTRAN, COBOL, or other high-level computer languages. Those microcomputers that can, in principle,
handle high-level languages still suffer in comparison
with minicomputers supplied by Digital Equipment
Corporation, Hewlett Packard, Data General, Varian,
and other manufacturers in the amount of available highlevel software.
If you want t o solve tomorrow's problem, you can
consider the purchase of a microcomputer system and
develop your own high-level software. If you want to
solve today's problem, pay particular attention to software support. Your time is valuable. If you are not careful, software costs can easily equal and exceed the total
hardware costs of your data acquisition system.
For the moment, then, it would be more appropriate
to call systems built around microprocessor chips microcontrollers or logic processors. They can sequence events
in response to decisions upon input data. As the price of
individual microprocessor chips drops from several hundred dollars per chip t o $10 to $30 per chip, it will be
clear that the dominant application for today's microprocessors will be as sophisticated control elements in
instruments and machines of all types. We forsee minicomputer-microcomputer and computer-microcomputer
hierarchies in which one to twenty instruments,
machines, or devices, each containing its own microcomputer, will all be tied to a single minicomputer or
computer.
the anatomy of a microcomputer
The "anatomy" of a typical microcomputer system is
shown in fig. 5. This system is based upon the 40-pin
8080 microprocessor chip and possesses all of the minimum requirements for a computer:
It can input and output data.
fig. 2. The 8 0 8 0 mlcroprocessor chip.
38
january 1976
I t contains an arithmeticllogic unit (ALU), located
within the 8080 chip, that performs arithmetic
and logical operations.
It contains "fast" memorv.
Random access
A semiconductor memory into
which logic 0 and logic 1 states can
be written (stored) and then read
out again (retrieved).
It is programmable, with the data and program
instructions capable of being arranged in any
seauence desired.
Read-only memory A semiconductor memory from
which digital data can be repeatedly
read out, but cannot be written into, as is the case for random access
memory.
It is digital.
Fig. 5 shows the important data paths within the microcomputer. In the sub-sections below, we shall dissect this
diagram and discuss each of the individual data paths.
table 1. Spectrum of computer-equipment complexity. Reprinted from Electronics, October 17. 1974;copyright @
McGraw-Hill, Inc., 1974.
Word
length
Complexity
1
2
hard-wired
logic
programmed
logic array
Application
8
4
calculator
under $100
64
32
minicomputer
dedicated
computation
control
Cost
16
microprocessor
large computer
low-cost
high-performance
general
general
data processing data processing
$1000
$10000
$100000
and up
Memory
size
very small
0-4words
Program
read-only
Speed
constraints
real time
Inputoutput
integrated
Design
logic
Manufacturing
volume
large
small
medium
large
2-10words
10-1000words
1000-1million words
reloadable
slow
medium
few simple
devices
some complex
devices
logic +
microprogram
Memory. Let us first consider the data communication
between the 8080 central processing unit, also known as
an MPU, and memory. You will require some definitions
I*
which will be useful in the ensuing disc~ssion:~
Memory
very large,
more than
1 million
words
Any device that can store logic 0
and logic 1 bits in such a manner
that a single bit or group of bits can
be accessed and retrieved.
Memory cell
A single storage element of memory.
Memory word
A group of bits occupying one storage location in a computer. This
group i s treated by the computer
circuits as an entity, by the control
unit as an instruction, and by the
arithmetic unit as a quantity. Each
bit is stored in a single memory cell.
Memory address
The storage location of a memory
word.
Memory data
The memory word occupying a
specific storage location in memory, or the memory words collectively located in memory.
microprogram
macroprogram
throughputoriented
roomful of
equipment
macroprogram
high-level language
software system
small
Programmable
read-only memory
A read-only memory that is field
programmable by the user.
Volatile memory
In computers, any memory that can
return information only as long as
power is applied to the memory.
The opposite of novolatile memory.
Read
To transmit data from a semiconductor memory to some other digital electronic device. This term also
applies to computers and other
types of memory devices.
Write
To transmit data into a semiconductor memory from some
other digital electronic device. This
term also applies t o computers and
other types of memory devices. A
synonym is store.
The 8080 microprocessor employs 8-bit words that
are stored in memory with the aid of a 16-bit memory
address bus. With the aid of a quick calculation, you can
conclude that there exist 216 = 65,536 different memory locations which can be accessed by the microprocessor. This access to memory is direct, which means
that you don't have to engage in any special tricks or
january 1976
39
digital electronic gimmicks to access any given memory
location within the 65,536 possible locations. Forty-pin
integrated circuit chips do have their advantages, and
this is one of them. The total memory capacity of the
8080 microprocessor i s known in the trade as "64k."
This is far more memory than you will ever need for
most applications, but i t is nice to know that you have
such power in reserve.
Data i s transferred between the 8080 CPU and the
memory over 8-bit input and output buses, both of
which are shown in fig. 5. By input we mean "input into
the CPU." The term, "output," i s defined in a similar
microcomputer instruction. A typical 8080 microcomputer system operates at a clock rate of 2 MHz and a
read or write operation takes only 3.5 microseconds.
Thus, RAM, ROM, and PROM all need an access time of
about one to two microseconds to allow you to take full
advantage of the maximum clock speed. Slower semiconductor memories can be used, but the microcomputer will have to wait while a read or write operation takes place.
data output
The 8-bit output bus between the 8080 CPU and
memory also serves as the output data bus to an external
output device. When you provide output to an external
device, there are several important points to remember:
You must select the specific output device that
will receive eight bits of data from the CPU.
You must indicate to this device when output data
i s available on the output data bus.
The device must capture this output data in a very
short period of time, typically 1.5 ps.
HARDWARE
LOGIC CONTROL-
SOFTWARE
f DATA
PROCESSING
fig. 4. Where microcomputers fit: between relay and discrete
logic and inexpensive minicomputers.
fashion. Our point of reference is always the CPU. Data
leaving the CPU is always considered to be "output
data;" data entering the CPU is always "input data." Fig.
5 shows that the input and output data is transferred
between the accumulator and memory. This is frequently the case, but in a more detailed look a t the 8080
chip, you will discover that data stored in memory is
transferred to other internal registers within the 8080
chip as well.
The most obvious such register is the instruction
register, from which the decoding of the instruction
occurs. Other registers, known as general purpose registers are classified by the letters B, C, D, E, H, and L. We
regard the accumulator register to be the heart of the
entire microcomputer. Arithmetic and logic operations
are always performed to or on the eight bits of data
present in the accumulator. All input and output data
passes through the accumulator with the aid of two computer instructions called IN and OUT.
Between the 8080 CPU and memory there exists a
single output line called memory READANRITE. When
this line i s a t logic 1, you are able to READ data into the
CPU either from memory or from an external device.
When this line is at logic 0, you are able to WRITE data
from the CPU into memory or an external output
device.
As a final point, you can employ any type of "fast"
digital electronic memory device, including random
access memory (RAM), read-only memory (ROM), and
programmable read-only memory (PROM). What do we
mean by "fast" memory? Simply that the memory can
perform either a read or write operation during a single
40
january 1976
The third point is perhaps the most important. Keep
in mind that the microcomputer is operating at a clock
rate of 2 MHz. Each computer instruction is executed in
a very short period of time which ranges from 2 to 9 ps.
Thus, accumulator data designated as "output data" to
an external device is not available for very long. You
must capture it while it is available. We will discuss the
techniques that you would employ in a subsequent column; this topic i s certainly among the most interesting
topics that can be discussed in the field of computer
interfacing.
data input
The basic considerations that apply to data output
also apply to data input into the CPU from an external
input device. Thus:
You must seleat the specific input device that will
transmit eight bits of data to the CPU.
You must indicate to this device when the CPU is
ready to acquire the input data.
You must insure that the CPU acquires this data in
a very short period of time, typically 1.5 ps.
inputloutput device addressing
The 16-bit memory address bus is time shared so that
i t can provide, at certain times, an &bit device identification number called a device code. Eight bits of information allow you to decode 28 = 256 different devices.
When used in conjunction with two output function
pulses called IN and OUT, the microcomputer system
can address 256 different input devices and 256 different output devices. We might point out here that a
"device" can be a complex machine such as a teleprinter
or cathode-ray tube (CUT) display, or a simple device
such as a single integrated-circuit chip. This is another
interesting topic for discussion that we will reserve for a
subsequent column.
SRI-1000
microcomputer interrupt
Not shown in fig. 5 is a single input line t o the microcomputer that generates a program interrupt during
microcomputer operation. Such an interrupt would be
generated by an external device that wishes to transfer
data to or from the computer. This particular topic i s
quite complex, and i t will be a number of months before
we tackle it in this column.
The above is about the best that we can do to describe the general "anatomy" of a microcomputer in
one-thousand words or less. Microcomputers are fascina-
I
MEMORY UP TO 65 536
I
8-B l T r n O I
I
Microcomputer
The SRI-1000 is designed around "PACE" National Semiconductors powerful 16- it Microprocessor. +he system is complete and allows the user t o connect i t to external devices
Immediately. With the addltion of the SRI-1020 plug in
board it will display data on a standard T.V Monitor the
SRI-lb40 for example. Also, b y plugging in 'the SRI-1010
board the system can "talk" to most any Cassette Tape
Recorber for loading programs or storin Information. I t also
other systems via
allows the SRI-1000 t o communicate ~ 7 t h
phone lines. etc. The SRI-1000 is controlled entirely from
the keyboard making i t extremely flexible. The main board
will accept i
p
t o six additional plug in optlons, and the
power supply is adequate t o handle both the SRI-1000 and
the options. I t Is housed i n a compact desk-top enclosure,
with room on top t o mount a Video Display.
The SRI-1000 includes the following
16-BIT MICROPROCESSOR
4K W ~ ~ D STATIC
S )
RAM
UP TO 1 d (WORDS)
EXPANDABLE PROM
I N T E R N A L POWER SUPPLY
53 K E Y KEYBOARD
RS-232 T T L A N D 20 MA. T T Y CURRENT LOOP
INT~RFACE
REAR PANEL CONNECTOR ACCESS
EDITOR. ASSEMBLER A N D DEBUG SOFTWARE
All the above comblne t o make for a versatile and very
powerful computer system that can handle the following
wlth ease, and more.
Business Applications - Can be used for inventory control
payroll computations and bookkeeping. Educational
AC:
quaint students with computer systems and programming
techniques. Security Field
Check and verify security
badges monltor intrusion devices fire and gas detectors.
Then ldentify the problem indicate the time and location
and read It out on a screen'or line printer. Hobbyist
Play
games such as "chess", or t o help you with experiments.
SRI-1000 MICRO COMPUTER SYSTEM
.$599
(16-Bit Processor
SRI-1010 C A S S E T T ~ . ibijkrij ir;(YkFiki=i" '
575
SRI-1020 VIDEO INTARFACE
$175
SRI-1040 12" R.F. VIDEO MON~TOR'
$125
SRI-1080A A D D I T I O N A L STATIC RAM 2K ~ W O U D S ~ $ ~ O O
-
cpu
-
-
I ~ J ~ ~ ~ ~ , ~ ~
PULSES
fig. 5. A typical 8080-based mlcrocornputer system.
-
ting machines. They are small and relatively inexpensive,
so you are less likely to be intimidated by them. They
are far simpler than their minicomputer and computer
counterparts and can be readily repaired by the simple
process of chip substitution. They appear to be the
proper answer to your childhood question, after the
Erector Set, what?
If you do not wish t o stretch out your learning process on microcomputers for twelve months or more, we
might indicate that we have just completed Bugbook 111
entitled Microcomputer lnterfacing Experiments Using
the Mark [email protected], an 8080 System. It contains approximately 600 pages of text and experiments on interfacing
and programming 8080-based microc~mputers.~
-
-
. ..
. .. . ...
.............
. .. .
SRI-200
RTTY
TERMINAL
references
1 . D . G. Larsen, P. R. Rony, and J. A. Titus, Bugbook / a n d I/.
Logic & Memory Experiments Using TTL Integrated Circuits,
E&L Instruments, Inc., Derby, Connecticut, 1974 ($16.95 for
the pair from Ham Radio Books, Greenville, New Hampshire
03048.)
2. D. Eadie, Introduction t o the Basic Computer, Prentice-Hall,
Inc., Englewood Cliffs, New Jersey, 1968.
3. W. 6. Riley, "Technology Update: Computers," Electronics,
October 17, 1974, page
4. R. F. Graf, Modern Dictionary of Electronics, Howard W.
Sams 81Co., Inc.. Indianapolis, 1972.
5. J. Blukis and M. Baker, Practical Digital Electronics, HewlettPackard Co., Santa Clara, California 1974.
6. D. G. Larsen, P. R. Rony, and J. A. Titus, Bugbook 111:
Microcomputer Interfacing Experiments using the Mark 80 an
8080 System, E&L Instruments, Derby, Connecticut, 1975
($14.95 f r o m Ham Radio Books, Greenville, New Hampshire
03048).
ham radio
.
RTTY T E R M I N A L . . from SYSTEMS RESEARCH, INC.
You may order the system complete - or any of five
modules.. whichever suits your needs best.
Speclal Offer valid only through Jan. 31 1976 - Purchase
SRI-200 and SRI-210. Receive SRI-230 i n d SRI-240 at no
extra cost.
SRI.200. Terminal unlt. Need only be connected t o the
output of any RTTY converter and t o any monitor either
video or RF) t o copy teletype. Price $399. Standardl T.V.
set.
SRI-210. Keyboard assembly. Allows you t o transmit RTTY
by simply connecting the output of the 210 t o any AFSK or
FSK unit. Price $199.
SRI-220. V ~ d e o display monltor. Mounts on top of the
termlnal t o make a compact desk top unit. Prtce $125.
sRI-230. RTTY converter board. Plugs dlrectly Into terminal
maln board. Accepts audio from any receiver.
SRI-240. AFSK board. Plugs dlrectly into keyboard assembly
main board.
A l l items assembled and tested. Allow approx. 30-90 days
delivery time. A l l items shipped postpaid.
Send cash or check with order or use charge cards.
Send NOW for FREE A D D I T I O N A L INFORMATION
.
P O Box151280
S a l t Lake C ~ t yU
. t a h 8 4 1 15
(8011 9 4 2 - 1 0 9 3
january 1976
41
four-watt
wideband linear amplifier
There i s no problem these days in building high-frequency, transistorized ssb exciters that produce outputs in the milliwatt range. However, there seems to be a
dearth of information on how to get these low-level signals up to a more useful level. Articles I've seen in the
amateur magazines seem mostly to use one of two extreme methods. One is to make use of the rather exotic
high-priced transistors designed especially for linear
power amplification; the other is to use some of the
newer audio power transistors - usually with great difficulty and often with not very satisfactory results.
A stable
rf amplifier
for QRP use
or as a driver
for higher-power
linear amplifiers
over the frequency
range from 300 kHz
to 30 MHz
features
This linear amplifier uses the widely available and
inexpensive (about $7.00) 2N5590 transistor to produce
a power output of 4 watts across the high frequency r f
range. This power level is suitable for the output of QRP
rigs or as a driver for a final amplifier in the hundredwatt range."
'This amplifier will drive the high-power linear amplifier
described by Chalmersl to full output.
i.
A. Koehler, VESFP, 2 Sullivan Street, Saskatchewan, Canada S7H-3G8
The amplifier gain is flat over the high-frequency rf
range, being only 3 dB down at 300 kHz and 30 MHz. In
fact, the amplifier still produces useful gain at six
meters. The exact gain will depend somewhat on the
transistor used, but the version I built had a midband
gain of 22 dB. This means that full output on the amateur bands up to 15 meters can be obtained with only 25
milliwatts of drive; 40 milliwatts is required at ten
meters. The amplifier output may be either shorted or
left open indefinitely with no damage even with full
drive. The amplifier is also very stable and shows no
tendency to oscillate.
heatsinks are good, an acceptable one can be made from
three sheets of 0.06-inch (1.5mm) aluminum formed and
assembled as shown in fig. 2. After all holes are drilled,
they should be deburred so the pieces will make good
contact with each other. It's a good idea to put silicone
grease or heatsink compound between the pieces before
final assembly.
circuit
The amplifier schematic is shown in fig. 1. The stability and wide frequency response are achieved by adding considerable negative feedback to an otherwise conventional broadband amplifier. The small inductance in
series with the 560-ohm feedback resistance decreases
the feedback at the higher frequencies. The exact value
is not critical. About 25 turns of number 30 (0.25mm)
wire closewound on a %-watt resistor will do very well.
The amplifier operates in the class-A mode, and the
transistor has a quiescent power dissipation of 5 watts. A
fairly efficient heat sink is required. While commercial
b
tl2V
One of the broadband transformers used in the input and output circuits.
fig. 1. R f amplifier schematic. T I , T 2 are wound on two-hole
balun cores as found in TV-set input circuits. Emitter resistor is
made from four 3.3-ohm. '/#-watt resistors in parallel. All capacitors are 100-volt plastic: rf chokes are 1 or 2 turns through a
ferrite bead.
construction
The circuit is built on a piece of single-sided circuitboard material mounted copper side up on the heatsink.
A large clearance hole for the transistor i s drilled in the
center so that the transistor can be mounted directly on
the heatsink. It's important to put silicone grease or
heatsink compound on the mounting surface of the
transistor before assembly. It's also important not to
overtighten the transistor mounting nut. Components
are mounted between pads of PC material approximately
0.39 x 0.39 inch (1 x lcm) cemented to the main circuit
board. Pad locations may be found by laying out the
components you wish to use on the board. The general
appearance of the amplifier (before adding components)
is shown in fig. 3.
The transistor tabs are fragile, so the transistor should
be mounted in its final position first and the components soldered t o the tabs later. Do not reverse this order
or the tabs will be stressed when you tighten the tran-
january 1976
43
shown in fig. 4 and the photograph. Using an ohmmeter
to identify the wires, one end of one wire is connected
to the opposite end of the other wire, which is the
center tap of the transformer. The wide frequency response of the amplifier is due to these transformers, and
the general method of construction should be followed,
although wire size, number of twists and number of
turns through the core are not too critical.
Chokes in the main supply line are made by winding
one or two turns through any of the widely available
ferrite beads. I used one turn through a two-hole bead
for each of the chokes. Large values of inductances are
not required here since the power-supply line operates at
very low impedance.
fig. 2. Method of constructing transistor heatsink. Aluminum
sheet is formed to approximate dimensions shown, then assembled. Hardware is 4-40 (M3). T o p holes are countersunk. Transis
tor stud clearance is drilled after assembly.
sistor mounting nut. The 0.8-ohm emitter resistor must
have a very low inductance, which may be achieved by
paralleling several higher-value resistors. I used four
3.3-ohm, %-watt resistors soldered symmetrically between the emitter tabs and the ground plane as shown in
the photograph.
Underside of amplifier. Emitter-resistor assembly is
shown paralleled between emitter tabs and ground
plane. Input and output transformers are at extreme right and left.
Fig. 3. Printed-circuit board and heatsink mounting details.
Mounting pads for components are made of PC board material.
The input and output transformers are wound on
two-hole balun cores as found in TV sets. The ones I
used are manufactured by Phillips; their type number is
4322-020-31520. The windings are made by twisting
two pieces of number 22 (0.6mm) enamelled wire together about three twists per inch (one twist per cm).
This twisted pair is then wound through the core as
No tuning is required, so the amplifier is made ready
for use merely by adjusting the quiescent current level.
First set the 47-ohm trimmer to minimum resistance
then connect the 12-volt power supply and adjust the
trimmer so that the total amplifier current drain is 0.4
ampere.
At the one-watt output level, the second harmonic
measured 30 dB down with respect to the fundamental.
I wasn't able to measure the intermodulation distortion
with the test equipment I had available. From the measured performance of similar amplifiers,* I'd expect i t to
be about -40 dB. For CW use, the quiescent current may
be lowered to reduce wasted power; however, the output
harmonic content will increase and the overall gain will
decrease.
references
fig. 4. Transformer winding details. No. 2 2 (0.6mm) enamelled
w i r e t w i s t e d pair is wound
through a two-hole balun core.
1. S. Chalmers, "High-Power, Solid-State Linear Amplifier,"
ham radio, August, 1974, page 6.
2. M . J. Kloppen, "Single-State Wideband SSB Driver Modules,"
Phillips Application Report ECO-7113, 1971.
ham radio
More Details? CHECK-OFF Page 102
january 1976
45
high gain yagi
for 432 Mhz
A new long-boom
16-element Yagi design
for 432 MHz
that provides
15 dB gain
over a dipole
For years the amateur uhf community has been trying to
come up with a reproducible, high-gain Yagi beam for
432 MHz. At one time it was generally agreed among
amateurs that the dimensions of a really long uhf Yagi
antenna were so critical that i t was impossible to build a
practical, reproducible, high-gain, multi-element beam,
and most uhf operators switched to the less critical colinear array. Unlike the long-boom Yagi, the colinear i s a
low-Q antenna, so none of the dimensions are overly
critical and it is easily reproduced for uhf operation.
46
january 1976
I
~
I
'
However, as has been pointed out by Ed Tilton,
WIHDQ,l it is possible to build Yagi antennas for 432
MHz (and other uhf frequencies) if a l l dimensions are
properly scaled. Most experimenters scaled element
length and spacing, but failed to scale either the element
or boom diameter - this resulted in antennas that
exhibited little more gain than a dipole, or worse.
W1 HDQ's 11-element, 432-MHz Yagi design was the first
that proved t o be reproducible, and although it uses a
wooden boom, large numbers are being used by amateurs on the 432-MHz band. The gain of the Tilton Yagi
has consistently measured about 13 dBd (gain over a
dipole).
Other successful 432-MHz Yagi designs are those of
WQEY E2 and K2R IW. WQEY E's 15-element design,
which uses a 10-foot (2.9m) metal boom, attracted wide
attention, but not everybody who tried t o build it was
successful. K2R IW's 13-element Yagi, which uses insulated elements (8-foot [2.4m] boom), has been quite
popular in the East, and has consistently been shown to
provide about 15 dBd gain.
Described here is another long-boom Yagi for 432
MHz which provides about 15 dBd gain. This has been
confirmed at antenna measurement contests on both the
East and West Coast. This Yagi, which was designed by
Mike Staal, WGMYC, and Me1 Farrer, KGKBE, of KLM
Electronics, is based on successful design techniques
By Ken Holladay, KGHCP, 2140 Jeanie Lane, Gilroy,
California 95020
proven on hf and vhf and uses a broadband driven structure which consists of three elements (fig. 1). This provides a reasonable operating bandwidth and ease in coupling to the 12 directors and one reflector. The broadband structure, in addition to providing optimum coupling to the directors, is the key t o reproducibility. Small
variations in dimensions can be tolerated without significantly changing the operating characteristics of the antenna.
ELEMENT
SPACING
I43 25' (363 9 cml
134 0 - 1340 4 cml
I 2 2 375' 13108 rml
1 0 8 5' 1275 6 cml
980.12489
sml
8 6 5' (219 7 cml
76 0' 11930 cml
construction
As is shown in fig. 1, the antenna is based on a 1-inch
(25cm) diameter boom, 12-feet (3.7m) long. Each of the
elements is 318-inch (9.5mm) diameter aluminum tubing, insulated from the boom except for the single
mounting screw (this type of element mounting must be
used for the dimensions given in fig. 1). The driven elements are cross connected using %-inch (6.5mm) wide
aluminum strap. The feedpoint impedance is 50 ohms
(balanced) and must be connected to a balun using lowinductance copper strap 5116 inch (8mm) wide." To prevent aluminum-to-aluminumand aluminum-to-coppercorrosion, all joints should be coated with Penetrox A or
equivalent weatherproofing. An acceptable balun can be
made as described by K6HCP and WA6GYD in the
A R R L Radio Amateur's VHF M a n ~ a l . ~
performance
At my station I have two of these antennas mounted
side by side, and they have provided the expected results. Los Angeles is about 300 miles (483km) away,
over mountainous terrain, and good solid contacts on
432 MHz are a nightly occurrence. Activity on 432 is
starting to increase, and I feel confident that this new
antenna, which is easy to build, will do a great deal to
stimulate growth on this band.
ELEMENT LENGTH
M75~11289
cml
3 9 125- 1 9 9 4 cml
2 6 125' 166 4 cml
15 25' 138 7 cml
8 5' 121 6 cml
5 5' 114 0 cml
2 5 ' 1 6 4 cmJ
+
10 5' 126 7 cml
10 75' 1273 rml
+
10 75' 1273 rml
0 7 5 - 1273 cml
(10. 1 2 9 9 cml
-+
10 75.127 3 rml
&
110. 1 2 9 9 cml
2
10 5' 126 7 rml
10 75' 1273 cml
11
5' 129 2 cml
4 5' 111 4 cmll2 REODl
4 6 2 5 ' 111 8 cml12 REODl
4 75- (12 1 rmJ12 REO'DI
12 8X' 132 7 cml
o- g?: !'JKJ- - - - - -..
BALUN CONNCC TS
TO POINT X X
fig. 1. Layout of the 16-element Yagi for 4 3 2 MHz.
Elements are 3/8" (9.5mm) diameter aluminum tubing.
insulated from the boom except for the single mounting
screw as shown in fig. 2.
'For those readers who do not have the time or material t o build
their own, this antenna is available from K L M Electronics,
17025 Laurel Road, Morgan Hill, California 95037.
references
1. Ed Tilton, WlHDO, "Antennas for 220 and 420 MHz," The
Radio Amateur's VHF Manual, ARR L , Newington, Connecticut,
1972, page 208.
2. Don Hilliard, WQEYE. "15-Element Yagi for 432 MHz,"
QST, January, 1972, page 96.
3. Dick Knadle, K2RIW. "13-Element Insulated Yagi for 432
MHz," The ARRL Antenna Handbook, 13th edition, 1974,
page 243.
4. Ken Holladay, KGHCP, and Don Farwell, WAGGYD, "Making
and Using Baluns," A R R L Radio Amateur's VHF Manual, page
170.
ham radio
fig. 2. First five elements of the high-gain 432-MHz Yagi, showing element mounting and balun installati0n.
The three-element. cross-connected driven structure is at the center.
january 1976
47
48
january 1976
More Details? CHECK-OFF Page 102
More Details?CHECK-OFF Page 102
january 1976
rn 49
telephone controller
for remote
repeater operation
Using a modified
RTTY autostart circuit
to activate
a repeater
without a telephone
An earlier issue of ham radio described a telephone controller that could be used to turn any device on and off,
such as a repeater.l Hopefully you've already read that
article, so we won't go into the actual telephone controller; instead we'll show you how to operate the controller without a telephone. Many have asked us how
this can be done, so we designed a circuit that will
decode a tone and change it to a dc voltage that will
allow the controller to be operated without a telephone.
We already had a circuit board that would do this.'
This circuit was originally designed for RTTY autostart,
and by simply retuning it to a chosen audio frequency,
we found that it worked perfectly as a tone decoder.
The RTTY autostart circuit is shown in fig. 1. All we
had to do was omit the relay, bring out the lead from 0 2
collector, and route it to the telephone controller junc*Available from Circuit Board Specialists, 301 1 Norwich
Avenue, Pueblo, Colorado 81008. RTTY autostart printed circuit board $3.50 each. Complete kit, lass power supply ( + I 8 to
24 Vdc) $14.50. (Specify approximate tone frequency.)
50
january 1976
tion of U1, pins 14 and R8.l On the original telephone
controller you can omit Q1, Q2 and Q3; CR1, CR2 and
CR3; R1-R7; C1-C4; and K1. (These parts were used to
validate the telephone line only.)
The circuit is a tone decoder that turns transistor Q1
on and off. A tone of your choice is fed into the circuit
from your receiver through R1 and decoupling capacitor
C1. The tone i s decoded by L1, C2. 0 1 i s a voltage
amplifier. The amplified tones are rectified by diodes
CR1 and CR2. The resulting dc voltage i s fed to the base
of Q2. Capacitor C7 requires about two seconds to
charge and discharge, resulting in Q2 turning on and off
at a rate similar to the ring rate from the telephone, as
decoded by the original circuit in the telephone controller. Therefore, assuming the telephone controller circuit has been properly programmed, one would ring
three times, hang up, wait twenty seconds, and ring
three more times. The same thing would be done with
the tone encoder on your mobile or base rig; i.e., push
the button three times for one second each (or longer);
stop; wait twenty seconds; then push the tone button
three more times.
The only thing that will take a little time is tuning the
toroid for the audio frequency you desire, which is done
with the aid of an oscilloscope or vtvm on the ac volts
scale.
Put the plus lead of the scope or vtvm to the gate of
Q1. Dc voltage need not be applied to the circuit. Apply
your desired tone to the input and open R1 all the way.
Adjust C2 for maximum ac volts or peak-to-peakvoltage
on the ocilloscope. Remember, the better the tuning,
the narrower will be the bandpass.
After it's all hooked together, apply a dc voltage
between +12 and +24 volts to the decoder board and
By Robert C. Heptig, KQPHF, Robert D. Shriner,
WA0UZO
Robert C. Heptig, KBPHF, P.O. Box 969, Pueblo, Colorado 81002,
Robert D. Shriner, WABUZO, 1740 E. 15th St., Pueblo, Colorado 81001.
m UOTDR
START RELAY
K-ENTERPRISES
r
MODEL 4X6C
50 HZ-250 MHZ ............... '270.00
fig. 1. RTTY autostart circuit, which is used with I C U1. the
SN7490 in the original article (reference 1). as a tone decoder. A
tone of your choice is fed into the circuit through R1. C 1 and is
decoded through L1. C2. K 1 is a Potter & Brumfield SC-4332.
300 and 500 MHz PRESCALERS
FREQUENCY STANDARDS
MARKER and PEAKING GENERATORS
POWER SUPPLIES AMPLIFIERS
telephone controller board, then test it as described in
reference 1 (with the exception of the validating circuit).
Adjust R 1 of the decoder board to allow just enough
audio to do the job with respect to the amount of deviation of your tones.
WRITE FOR FREE CATALOG
tone access
Just for the fun of it we added a tone access for your
repeater to the circuit. Simply put the relay back into
the circuit of the R T T Y autostart as shown in fig. 1 and
wire it into your repeater as shown in fig. 2. In this
configuration the COR cannot be keyed unless a brief
tone i s applied to your carrier, which will cause the
modified R T T Y autostart circuit to provide a ground for
.........
:..:.:.:.,.
..>:
.........
........
:.:.:.:_
.:......
.....
,%;
....
. . .
.:.:.:.:.
.........
.....
::.....
::::.::
K-ENTERPRISES
1401 N. Tucker
.........
:::::::::
iiiii
Shawnee. Okla. 74801
INTERNATIONAL MORSE DECODER
SMRE SET OC Q*YTAcTS
ON CARRIER-DPERATED RELAY
fig. 2. Tone-access circuit
for repeaters. A brief tone
a p p l i e d to y o u r c a r r i e r
causes the modified autostart circuit to ground your
COR as long as the carrier
Is present.
FIWRE I
lnternational Morse Code
Parallel ASCII OUT
IN
$73
Television Display Circuit
ASCll IN; Display a single row of up t o 30
characters on your TV screen.
$118
your COR; then a spare set of contacts on your COR
will maintain ground as long as your carrier is present.
By tuning the decoder as a broadband amplifier (increase
values of C1 and C3). this circuit could be used for a
vox-operated repeater. With a l i t t l e imagination, you can
probably come up with many possibilities for this
decoder.
Audio Converter Unit
Couple your receiver to the lnternational
Morse Decoder; Two stage active filter plus
level detector; Can also be used to drive an
audio oscillator for static free CW reception.
$19
The above circuit boards are shipped assembled and tested
reference
PIGON
1. Robert C. Heptig, KBPHF and Robert 0.Shriner, WABUZO,
"Automatic Telephone Controller for Your Repeater," hem
radio, November, 1974, page 44.
ELECTRONICS
ham radio
...
P. 0. BOX 2192
MESA, ARIZONA 85204
i
january 1976
51
Who
the bestammete
And savesyou
You do!
Heathkit state-of-the art
2-M transceiver with true
Unmatchable feature-packed value
Just compare True digital frequency synthesizer for unlimited frequency selection with no crystals to buy.
Lever switched frequency selection with digital readout-just flip the front panel lever controls to select
any frequency in any 2MHz segment of the 144 to
147.995 MHz operating range. LED status lights to
let you know that the synthesizer is "locked" on the
frequency you dialed and whether the channel is in
use. Automatic offset plus built-in tone encoder so
vou can work rematers. A minimum of 10 watts outbut and infin~teVSWR w~thoutfallure A hot recelver
w ~ t h0 5 pV sensltlv~tyand Schmlttquelch w~tha threshold of 0 3pV or less
The HW-2026
IS also one of the
smallest synthes~zedrigs ava~lable
And it's easy to
) b u ~ l d There are
just 5 c l r c u ~ t
boards, and alignment
requlres only a VTVM A
frequency counter helps, but
you can do the job wlthout one
L~ke
we sa~d,when you
want the best, and you want
to save, you want a Heathkit rig.
Kit HW-2026 Transceiver. . . . . . . . . . . . . $289.95
plus s h i w ~ n g
Kit HWA-202-1
AC power supp,yS32.95
PIUS s h i m ~ n g
Heath Company, Dept.122-13 Benton Harbor. MI 49022
builds
9
transceivers.
Heathkit handheld
2-M transceiver:
#,
The HW-2021is a 5-channel transceiver which
has a repeater Simplex offset switch for each
channel.The kit comes with a crystal which will
work 146.94 MHz Simplex and .34-.94 repeater.
Output is one watt minimum with 0.005%(or better)
stability. And the unit has true FM and a built-in
separate microphone for better audio.
A rechargeable nickel-cadmium battery pack
and charger are included at no extra cost.
An optional Auto-Patch encoder gives you
the added versatility of placing telephone calls
through repeaters set up for touch tone operation.
Kit HW-2021 Handheld Transceiver. . . $169.95
plus shioplng
HWA-2021-2 Carrying case & stra~.. . . $ 12.95
plus shipping
Kit HWA-2021-3 Auto-Patch encoder. . $ 39.95
plus shlppng
I
HWA-2021-4 Crystal certificate (only
one required for each transmit1
receive channel). . . . . . . . . . . . . . . . . $
6.95
~osl~ald
The world's largest catalog
of electronic kits.
Send for your copy today.
Because of the unpreceden
demand for these great new prc
deliverv on orders will tak
lip to 6 weeks.
o insure thf!earliest
ivery, call
ossible
-..- deli
:.. ,,.
LU LllG
+kn
ur Hotline:
-
616-982-3411
L
cedure. I f you have solved a particularly difficult equipment problem, we would like t o hear about it. There
may be others who will be helped by your success.
basic troubleshooting
Michael James
basic troubleshooting
Troubleshooting and equipment repair are two of the
toughest problems faced by radio amateurs today. Part
of the difficulty is due to the fact that modern ssb
equipment is much more complex than the old a-m and
CW gear of twenty years ago, but perhaps more important, few amateurs build major pieces of their station
equipment anymore so they are probably not as familiar
with its circuitry as they should be. When your receiver
or transmitter starts giving you trouble, more than likely
i t will be returned to the factory t o be repaired. If the
problem isn't too severe, you may avoid using that function which is affected or overlook i t altogether. In some
cases you may not even be aware of a problem unless
another amateur brings i t to your attention (distorted
speech, poor sideband suppression or splatter, for
example).
Although there may be some equipment repair problems that are best sorted out by the factory, in most
cases you can save yourself a lot of time and money by
fixing i t yourself. Once you send your gear back t o the
factory, you may have t o wait a month or more until
you can get back on the air. In addition, you will probably have t o pay the factory ten dollars an hour or more
for their technician's time.
Troubleshooting electronic equipment is not difficult,
nor does it require a bench full of test equipment. A
large selection of test equipment may simplify the task,
or allow you t o solve a problem more quickly, but 90
per cent of all troubleshooting can be accomplished with
a volt-ohmmeter and other simple test equipment you
already have on your workbench. In those cases where
you need a calibrated signal generator or an oscilloscope,
you can often borrow one from your local radio club or
from an amateur who lives nearby.
In the coming months this column will be devoted t o
troubleshooting techniques and how you can use them
t o fix your own equipment. Although much of the initial discussion will be in general terms that are applicable
t o practically any electronic equipment, future columns
will discuss specific pieces of equipment and unique or
unusual circuitry that requires a somewhat different pro-
54
january 1976
There are three basic troubleshooting techniques
which can be used t o locate and fix circuit malfunctions:
signal tracing, resistance measurements and voltage measurements. In receivers and transmitters the problem area
is usually located with signal tracing, then pinpointed
with resistance and/or voltage measurements. Although
some electronic circuits such as gain-control circuits
don't lend themselves t o signal tracing, the majority of
receiver and transmitter circuits can be quickly checked
with this method. Once you know how to use signal
tracing, in fact, you will probably agree that it's one of
the quickest ways to track down a circuit problem.
Basically, signal tracing consists of injecting a signal at
the input to a piece of equipment and checking its path
through the equipment. If the signal appears at the input
t o a stage, but not at the output, that stage is the culprit.
I t may not be the only culprit, but once it's been fixed,
you can locate other problem areas along the signal path.
The signal tracer is essentially a very quiet, high-gain
audio amplifier with headphone or speaker output.
One commercial version which is available at modest cost is shown in the accompanying photograph.
If you wish, you can build a simple high-gain audio
amplifier around an op amp IC as shown in fig. 1,
and in a pinch you could even use one channel of your
loot
8 onM
SPEAKER
fig. 1. Signal tracer circuit which is based o n t h e 7 4 1 o p a m p ICs.
Gain is about 8 0 dB; audio power o u t p u t is approximately 40
m W , sufficient f o r most signal tracing.
stereo system. This is all you need if you're working
with audio systems, but if you're troubleshooting rf and
i-f stages, you will also need a simple demodulator probe
such as that shown in fig. 2. The one I use is built into a
discarded plastic ballpoint pen. You can also use one of
the rf probes which are available for vacuum-tube voltmeters.
In addition to the signal tracer (audio amplifier and rf
probe) you will also need a signal injector - a device
which has a broadband signal output from audio through
vhf. There are several pencil-sized signal injectors on the
market for less than ten dollars. Most consist of a simple
1 kHz multivibrator which has high harmonic content
well above 30 MHz. The circuit in fig. 3, which uses
way to find the bad circuit is to check signal output
about halfway through the set. A good point is the output of the second mixer. If the receiver is connected to
an antenna the signal you hear should change as you
tune the vfo (since the demodulator probe is an a-m
detector, ssb signals will be unintelligible). If your reRF
-
C7
1
HIGH I - F
I
I
I
the offending one.
The divide-and-conquer technique of stage isolation
works just as well for other symptoms as i t does for a
radio that i s completely dead. You can hunt noise or
hum, for example, tracking down the stage where the
trouble first appears. It also works for distortion.
I
I
LOW I - F
I
WDlO
-
I
I
//
fig. 4. Sectionalizing an amateur communlcatlons receiver by functions. Dividing it u p this way makes
it easy to track down trouble with the signal tracer.
ceiver will tune to one of the WWV channels, this makes
an excellent test signal, or you can use your signal injector. The pitch of the wideband injector signal, however, will not change as you tune the vfo.
If the signal i s okay at the output of the second
mixer, you have cleared the front-end circuits of any
suspicion and can proceed to the last half of the set the output of the low i-f amplifier is a good point. If you
don't get an output from the second mixer, the low i-f
and audio sections are probably okay.
Assume You get nothing at t h e output of the second
mixer. Divide the front end roughly in half and use the
tracer and demodulator again. The output of the first
mixer i s a good check point. If you have the proper
signal there, there's something amiss in the bandpass
filter, vfo or second mixer. If there's no signal output
from the first mixer, the rf amplifier, crystal oscillator or
first mixer stage must be at fault.
The last half of the receiver can be attacked with
similar logic. If the signal was okay at the second mixer,
the next logical dividing point is the output of the detector, which can be checked directly, without the probe. A
signal in the tracer means that everything is okay up to
there and the trouble i s in the audio section. If you
don't get a signal, check the output of the other detector. No signal means it has been blocked between the
second mixer and the detector - the crystal filter or one
of the i-f amplifiers is the problem.
Note that with only two signal tracer checks you have
ioslated the problem to one small, functional section of
the receiver. If the signal is okay at the input to a stage
and not at the output, it's obvious the trouble i s between those two points. lt's a simple matter to check
each of the individual stages within a section to pinpoint
other checks
If the receiver is suffering from poor sensitivity, the
problem can be signal traced by the "straight through"
method. If reception i s poor, the fastest way to determine which amplifier isn't doing i t s job is to check the
gain of each stage by touching the signal-tracer probe to
the input and output; if there is little or no increase in
signal strength, the amplifier is weak. Although transistor mixer stages usually have some gain, vacuum tube
mixers seldom exhibit gain and may often have a small
signal loss, so keep this in mind. The filters introduce
loss, too, but you can judge if it's too much after you
have a little practice.
There are other little tricks of troubleshooting logic
that make it easy to find troubles. If your receiver works
alright on a-m but not on ssb or CW, for example, the
difficulty is probably with the product detector or bfo -
fig. 5. You can check these components with your signal tracer
without even unsoldering them from the circuit.
they are the only stages which are not common t o a-m.
If weak signals sound okay, but strong ones distort, a
good suspect i s the agc stage which may not be controlling the rf and i-f gain as it should, letting strong signals
overload the receiver. Likewise, frequency jumping or
drift can usually be traced t o the vfo; audio distortion
eliminates all but the detector and audio stages; and
poor selectivity i s usually caused by a bad crystal or
mechanical filter.
probe of the signal injector t o the input of each stage,
starting at the audio output stage, and move back toward the front end, stage by stage. If everything is working properly you will hear the 1 kHz modulation
through your receiver's speaker as you inject signal into
each stage.
Finally, you can check the B+ line with your signal
tracer for any traces of hum. Power supply filter capacitors are like any other bypass capacitors in that they
should shunt all signal voltages t o ground (power supply
ripple in this case) and leave only pure dc. I f one of the
filter capacitors i s weak, you'll hear a considerable
amount of hum in the signal tracer. If the dc line isn't
properly decoupled you may hear a whistling or hissing
sound that is an rf or i-f signal if you could unscramble
it. This can usually be traced t o a bad bypass (decoupling) capacitor somewhere along the B+ line.
getting closer
After they've pinpointed the stage which is causing
the problem, many technicians put away their signal
tracer and reach for their voltmeter. However, the signal
tracer can still tell you things about the circuit you can't
find out with a voltmeter. I n the amplifier circuit of fig.
5, for example, the highlighted coupling and bypass
I
SPEECH
I
I
I
LOW I - F
HIGH I - F
I
I
R F POWER
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
BFO
I
VFO
I
I
I
I
I
I
I
CRYSTAL
I
OSCILLATOR
1
-
I
ALC
I
I
I
I
--
__I
fig. 6. Modern ssb transmitter can be sectionalized b y function for troubleshooting purposes.
components can be tested right in the circuit without
even unsoldering them.
The coupling capacitor, C1, and the interstage transformer, T I , should pass the signal along with very l i t t l e
attenuation. Whether they are large, as in audio stages,
or small, between r f or i-f amplifiers, there should be
about the same amount of signal on both sides. If there
is any attenuation, i t should be small. To check, touch
the tracer probe t o the input side of the component,
then t o the output side - if the output is much weaker
than the input, the part is defective.
The bypass capacitors, C2 and C3, shunt the signal to
ground and their values are chosen t o short out practically all the signal at the emitter (C2) and at the power
supply end of the interstage transformer (C3). The tracer
should hear very little signal at either point. If there's
any substantial signal the capacitor isn't doing its job.
Even i f the transistor is in good health, bad bypass
capacitors at C2 or C3 will seriously degrade the gain of
the stage.
Sometimes, when checking stage gain or components,
you'll find that you don't have sufficient signal strength
t o determine i f a component is doing the job i t should.
In this case it's helpful t o place the signal injection
directly at the input t o the stage. This will bring the
signal level up t o the point where you can make meaningful measurements. You can also use the signal injector
to quickly move through the receiver t o determine
which stage is causing the problem. Simply touch the
transmitter signal tracing
A modified form of signal tracing is also suitable for
tracking down problems in ssb (and a-m) transmitters. In
this case the signal injector is connected to the microphone jack and the transmitter is terminated in a
dummy load as shown in fig. 6. Except that the position
of the stages i s reversed (audio front-end, rf output), the
functions of the various stages in a modern ssb transmitter are not that much different than those in a superheterodyne receiver.
By using the signal tracer t o track through the stages
of the transmitter, you can quickly locate a stage which
is blocking the signal (use the demodulator probe for the
balanced modulator output and all following stages).
The rf output from the final amplifier may be a little too
much for the detector diode in the probe so don't connect it directly t o the output - placing the probe tip
next to the power amplifier compartment should provide enough signal for tracing purposes.
Although the signal tracer won't track down distortion, poor sideband suppression, or vhf parasitics in the
transmitter, it's useful for quickly isolating a nonfunctioning stage or component. The signal tracer can also be
used t o eliminate hum and locate bad decoupling capacitors which are causing unwanted r f feedback. Other
transmitter troubleshooting techniques will be discussed
in a future column.
ham radio
january 1976
n/J 57
"FACTORY DIRECT ONLY"
n
"WILSON GOES MOBILE"
introducing the new WE-224
WE-224; 52/52, SIMPLEX PLUS
TWO TX/RX CRYSTALS, YOUR CHOICE
(Common Repeater Frequency Only),
MOUNTING BRACKET; MOBILE MlKE
SPECIAL
INCLUDES:
1402SM H A N D HELD
FEATURES
2.5 WATT
1402 SM 1405 SM
TRANSCEIVER
6
144-148 MHz
..
8 Channel Operation
Indlvldual Trlmmcrs
o n a11 T X / R X crystals
A l l Crystals Plug In.
1 2 K H z Ceramic
Filter
..
Channel Operation
Indlvldual Trlmmars
o n ail T X I R X Crystals
A l l Crystals Plug I n
12 K H z Ceramlc
Fllter
10.7 and 455
.
.1 M1crov011
less Battery
S-Mcter/Battery
lndocator
Slrc: 1 7 1 8 x 1 7 1 1
x 2 718
2.5 Watts Mlnlrnum
output.
12 V D C
Current Draln R X
14 M A T X 500 M A
M l c r o s w l t ~ hMIke
Button
.
..
lass Battery
Battery I n d l u t o r
Sirs: 1 711 x 1 114
x 2 718
Swltch8bla 1 l 5
Watt1 M l n l m u m
12 VOC
output
Current Drain: R X
14 M A T X 4 0 0 M A
(Iw) 900 M A (5W)
M I E ~ o ~ w I MIKE
Ic~
Button
Unbraakabla L e x a n a
Case
.
.
.
.
1
FEATURES
1.24 Channel Operation
2. One priority Channel
3. Selectable 1 or 10 Watts Out
4.10.7 Monolithic Filter Installed
5.455 KHz Ceramic Filter
6. Numerical Readout on each Channel
7. Built-in Adjustable "Tone- Burn" Generator
8. Front Panel Tone Encoder Control
9. Accepts Wilson 1402 & 1405SM Xtals
10. Individual Trimmer Capacitors for both TXIRX
11. Modet Front End
12. Helical Resonator
13. High VSWR Protection Circuit
14. Reverse Polarity Protection Circuit
15. NBFM - 15 KHz Channel Separation
16. External Speaker Jack
17. Built-in Speaker
18. Dynamic Microphone lnduded
19. Mobile Mounting Bracket lnduded
20. Frequency Range 144-148
21.6X"Y x 2H"H x 9X"D
22. Weight: 5% Ibs.
23. Power Requirements:
Source: 13.5 VDC 10%
Receive: .45A
Transmit: 2.6A (10W). .7A (1W)
*
1 4 0 5 S M HAND HELD
5 WATT
TRANSCEIVER
144-148 MHz
H A N D HELD
ACCESSORY
SPECIALS
DESCRIPTION
-
SUCIAL
CllCC
e C 1 - B A T T E R Y C U A R Q E R $18.95
BP N I - C A D B A T T E R Y
PACK.
15.00
L C 1 1402 L E A T U E R
CASE
14.00
LC2 L E A T H E R CASE
F O R 1405.2202.4S02
14.00
SM2 - S P E A K E R M I K E
F O R 1402 A N D 1 4 0 5 . .
29.85
T E I SUB-AUOIBLE TONE
ENCODER I N S T A L L E D . .
19.95
TTP TOUCH TONE P A 0
INSTALLED..
S5¶.65
X F 1 10.7 M O N O L I T H I C
I F X T A L F I L T E R INST..
$10.00
CRYSTALS: T X OR R X
( c o m m o n Freq. O n l y ) .
4.50
..................
- ..................
....
.....
..
...........
...
......
SPECIAL ON EACH RADIO INCLUDES:
1. Antenna
4.52152 Xtal
BC-1 NI-CAD
BATTERY CHARGER
WITH REGULAR AND
TRICKLE CHARGE
FEATURE
18
january 1976
More Details? CHECK-OFF Page 102
gpp&
-8
announces the addition of
wo
AND
2202 SM
4502 SM
FREQUENCY RANGE 222 - 225 MHz
FREOUENCY RANGE 442 - 450 MHz
6 Channel Operation
individual Trimmers o n a l l T X / R X Crystals
A l l Crystals Plug I n
1.2 K
H.z- Ceramic F i l t e r
. ~.
10.7 and 455 K C I F
.3 Microvolt Sensitivity f o r 2 0 Db Quieting
Weiaht: 1 ~ b .14 oz. less Battery
Battery lndicator
Size: 8 7/8 x 1 3/4 X 2 7 / 8
Switchable 1 & 2.5 Watts O u t p u t
6 Channel Operation
Individual Trimmers o n all T X / R X CryStalS
A l l Crystals Plug I n
12 KHZ ceramic Filter
10.7 and 455 K C I F
.3 Microvolt Sensitivity f o r 2ODb Q u k t i n g
Welght: 1 ~ b .14 or. l e u Battery
Battery Indicator
Size: 8 7/8 x 1 3/4 x 2 7 P
Switchable 1 & 1.8 Watts O
- u t .o u t
@ 12 VDC
Current Drain: R X 1 4 M A T X SO0 M A
Microswitch M l k e B u t t o n
Unbreakable Lexanm Case
8
- 1. 2
- VDC
12 V D C
2.5 Watts M i n i m u m O u t p u t
Current Drain: R X 1 4 M A T X 5 0 0 M A
Microswitch M i k e B u t t o n
Unbreakable Lexanm Case
USES SAME ACCESSORIES AS 1405
USES SAME ACCESSORIES AS 1405
INTRODUCTION SPECIAL
INTRODUCTION SPECIAL
INCLUDES
1.4502SM
3. Battery Pack
2. Antenna
4. Leather Case
5.446.00 Simplex Installed
INCLUDES
1.2202 SM
3. Battery Pack
2. Antenna
4. Leather Case
5. 223.00 Simplex Installed
TO: WILSON ELECTRONICS CORP.,
4288 S. POLARIS AVE., LAS VEGAS, NEVADA 89103
(702) 739-1931
JANUARY FACTORY DIRECT SALE ORDER BLANK
1405 SM @ $279.95.
1402 SM @ $199.95.
BC1 @ $36.95.
SM2 @ $29.95.
BP @ $15.00.
-TE1 @ $39.95.
LC1 @ $14.00.
ENCLOSED IS
CARD #
1
TX XTALS @ $4.50 ea.
-.RX
XTALS @ $4.50 ea.
B.
EQUIP TRANSCEIVER AS FOLLOWS: XTALS A.
D.
LC2 @ $14.00.
( SPEC1FY FREQUENCY
-TTP @ $59.95. -XF1 @ $ 1 0 . 0 0 . .
C.
WE-224 @ $209.95.
4502 SM @ $299.95.
2202 SM @ $279.95.
F.
E.
CHECK
MONEY ORDER
MC
BAC
EXPIRATION DATE
NAME
ADDRESS
I
ClTY
STATE
ZIP
SIGNATURE
Add $5.00 per Radio for Shipping, Handling; and Crystal Netting.
NEVADA RESIDENTS ADD SALES TAX
HR
SALE VALID JANUARY 1 THRU 31,1976
More Details? CHECK-OFF Page 102
january 1976
I
59
RAM keyer update
Circuit improvements
for the
random access memory
electronic keyer
described in a
previous issue
I
Redesign of the keyer for higher speeds is easily accomplished by noting fig. 1. The IC manufacturer gives the
clock frequency in terms of RA, RB, and C as:
II
where RA = 1k ohm, R, = 6.8k t o 56.8k ohms and C =
6.8 pF. Converting the clock frequency t o keying speed,3
speed (wpm)
1
I
This i s a followup report on the two-RAM programmable keyer article in the October, 1973, issue of ham
radio1 and my correction note2 in the December, 1974,
issue. Many inquiries have been received concerning possible parts procurement and solutions for faulty keying.
This article will enable you t o build this keyer with a
minimum of frustration.
(
clock circuit
Clock pulses are derived from a NE555 timer connected for astable operation; i.e., as a free-running multivibrator. Using the values of the original article, the maximum theoretical keyer speed will be about 17 wpm.
60
Fbl january
1976
=
1.73
(RA + ~
R ~ ) C
so that the speed range i s expected t o be from 2.2 t o
17.4 wpm. Fig. 2 shows the values of C and (RA + 2RB)
for the desired speeds. Using C = 6.8 yF the graph shows
that the speed varies when the resistance changes from
14.6k t o 114.6k ohms. In my case, a 3.3k resistor was
used in place of the 6.8k, and a 5 pF capacitor was used.
Maximum keying speed was then 32 wpm, and a slight
reduction in the duty cycle of the clock pulses (8%)
occurred, which didn't affect the keyer performance.
The 50k pot should have a log rather than a linear taper
t o permit a linear speed range; otherwise the higher keying speeds will crowd together near the upper portion of
the pot rotation
random-access memories
The second largest number of inquiries was about the
RAM devices. The (Signetics) 25L01B is the low-power
dissipation, pin-for-pin equivalent of the popular 1101
256-bit RAM (National Semiconductor and others). I
first used the 25L01 B " without any problems. I f its
price is a little too high for you, you can try the 1101
version as advertised by large discount houses in the
amateur literature (about $2.50 each). My experience
has been that you get what you pay for. I bought a half
dozen of these bargain specials and only one worked
correctly. I f you expect a cheap bargain, you'll probably
get a cheap device. Caveat ernptor.
printed-circuit board
The majority of inquiries were about the procurement of the printed-circuit board. As indicated in the
original article, the board, as well as the k i t of parts for
the keyer, could be obtained from the indicated address.
I t now appears that this company is no longer the source
for the parts or the printed-circuit board. If you have a
lot of time and patience the circuit can be hand wired.
In fig. 4 a full sized view of the etched board, from the
foil side, is shown for those who would like t o build one.
The layout of the components and external connections
are shown in fig. 5. This board diagram i s free from the
errors of the original version and incorporates the circuit
change as described in reference 2.
Speed (wpm) = 1.2f
II
By
faulty keying
Even after incorporating the changes in the correction
note,2 some readers still had problems with sending code
'Obtained from Schweber Electronics, 5640 Fisher Lane, Rockville, Maryland 20852 at $6.50 each.
Howard M. Berlin, KSNEZ, 2 Colony Boulevard,
Apt. 123, Wilmington, Delaware 19802
characters. This annoying problem arises from stray rf
and spikes generated from the TTL logic. In his article
WB4VVF discusses some possible
on the Accu-Ke~er,~
cures. I t is essential that all external leads be shielded
from rf. Use RG-174lU or similar coax from the keyer
output to the transmitter. If an external paddle is used,
use shielded three-wire cable from the paddle to the
keyer. As a further precaution, add 0.1 pF bypass capacitors on the three inputs of the paddle at the input jack.
TTL spikes can usually be eliminated by adding 0.01 p F
capacitors from each IC chip's +5 volt pin to ground. In
more stubborn cases i t may be necessary t o place a number of 0.01 to 0.1 pF capacitors around the edge of the
printed circuit board (ground) to +5 volt points. I used
about eight additional capacitors and have the keyer
right next to my kilowatt linear without any trouble in
keying.
Another tip on bypassing to cure faulty keying was
received from Ken Beck, K3DW. He found that false
KEYING SPEED (WPM)
10
'
rw
2
3
4 5 6
8
" " " "
2
'
10
15
'
t o 2 5 3 0 40-60
" " " "
-
2
3
4
5
a
304050
IW
CLOCK FREQENCY (Hz1
fig. 2. Capacitance. C, and resistance, ( R A
obtain desired keying speeds.
+
Re), required to
through a normally closed switch, which is bypassed by
a 0.01 pF capacitor. When the clear switch i s depressed,
a 0.1 pF capacitor discharges into the reset input of the
7473 that controls the address cycle. This ensures that
not only will the remainder of the address cycle during
which the switch was operated be cleared, but that a
new cycle will be started and cleared. In the write mode,
complete memory erasure is provided.
transmitter keying and sidetone
fig. 1. NE555 timer I C connected for astable operation.
dash generation occurred due to transient triggering of
the master flip-flop in the 7473 IC. To eliminate the
transients requires the addition of a disc capacitor bypass (0.02 to 0.05 pF) directly between pins 4 and 11 of
this 7473. Similar bypassing of the 7473 that controls
the address cycle also helps to prevent unwanted cycle
starts caused by transients. Also disc capacitors (0.02
p F ) connected from each key lead t o chassis (installed
right at the key jack) helped to reduce false triggering.
In any case, bypassing i s necessary to eliminate keying transients.
Another possible cause of faulty keying is in the
clock circuit. As mentioned before, the clock is freerunning and will continue to run until power is disconnected. Faulty keying may occur if the pulses of the
individual Morse code characters are not in synchronization with the rest of the logic. The only way to cure
this is to redesign the clock to run only when the desired
characters are being sent.
A relay output to key the transmitter can be used to
replace the 2N4888 keying transistor shown in the original circuit (see fig. 6). The 5-volt reed relay, which is
similar to that provided by Electronics Applications
Company part no. 1A5AH," provides excellent keying
even at speeds above 35 wpm.
An improved keying monitor to replace the 7413
NAND Schrnitt trigger5 is also shown in fig. 6. This
DRIGINAL CIRCUIT
ADDED CIRCUIT
momentary clear switch
A useful addition to this keyer circuit, offered by
K3DW, is a momentary switch t o clear the memory during either read or write operation, fig. 3. The 6.8-pF
timing capacitor for the NE555 clock IC i s grounded
fig. 3. Addition of clear switch to clear keyer memory during
read or write mode (contributed b y K3DW).
january 1976
Gli 61
-
--
fig. 4. Full-size etched circuit board layout. Component placement is shown in fig. 5.
.
.
TO TRANSMITTER
5.
WRITE
R/W
fig. 5. T o p view, component side of PC board.
with external connections.
62
january 1976
circuit uses a NE555 wired as an astable multivibrator
similar to a circuit used by WA5TIS6 If you don't want
the added expense of the 500k pot, a resistor of about
150k ohms should provide a pitch pleasing to the ear,
with the components shown.
construction notes
The printed-circuit board must be insulated from the
metal cabinet by short standoff insulators. Also, if the
keying paddle input jack is not insulated from the
chassis, the PC board must be insulated from the
cabinet. If you ground the board, insulate the input jack.
In either case the keyer output jack should be insulated.
summary
All the troubleshooting concepts mentioned resulted
from approximately 170 manhours debugging this keyer
after it was assembled. Troubleshootingwas done with a
four-channel storage oscilloscope and a lot of patience.
I
I
I
STATION
' Reference 112 w m d ~ ~ o l e
'' Reference 114 wave whip used a gson stand
I
_
ard by many msnufacturem
fig. 6. Alternative method for keying transmitter using a reed
switch. (A). A simple keying monitor is shown in (B).
I . . . designed by professionals I
If you don't have access to this equipment, this article
will be of use to you. You might want to include the
additional memories described in reference 5.
. . . smart in looks, practical in design, light
I to professional standards!
in weight, exclusive in matching and phasing system, the ultimate in "capture area"
. . . we call RING0 RANGER, "Mr. Pro!"
This offers hams a superior omni-directional
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of radiation for higher gain and extended
coverage. Easily mast or tower mounted.
In stock worldwide with your distributor.
*Electronics Applications Co., 2213 Edwards Avenue, South El
Monte, California 91 733.
reterences
1. Michael Gordon, WBSFHC, "Electronic Keyer with RandomAccess Memory," hem radio, October, 1973, page 6.
2. Howard M. Berlin, K3NEZ. "Memory Keyer," (Comments),
ham radio, December, 1974, page 58.
3.The ARRL Radio Amateur's Handbook, ARRL, Newington,
Connecticut, 1973 Edition, page 356.
4,James M. Garrett, WB4VVF, "The WB4VVF Accu-Keyer,"
QST, August, 1973, page 19.
5. Howard M. Berlin, K3NEZ. "Increased Flexibility for the
Memory Keyer," ham radio, March, 1975, page 64.
6. Joe Buswell, WASTRS, "Simple Integrated-Circuit Electronic
Keyers," ham radio, March, 1973, page 38.
ham radio
I
1
4!br1-
C O R P O R A T I O N
621 HAYWARD ST., MANCHESTER, N.H. 03103
)
INPUT
Irn
COYP
lNm
15
$0
T;sl
NC
Vt
11
10
I
I
NON-IW
INFWT
BIAS
OUTPUT
COMP
9
d
CA313lEM-
CAJ132EM
TOP VIEW
V-
SOURCE GNO
OUTPUT
NC
I
NC
fig. 2. Pin-out diagram of the RCA CA3131 and
CA3132 audio power ICs. The CA3131 has an lnternal feedback network that maintains overall galn at
about 4 8 dB. The CA3132 has no internal feedback
but one can be connected externally (see text).
audiompower integrated circuits
Audio-power ICs are available in the 5-watt and higher
ranges for many applications. Some include an integrally
designed heatsink as part of the package (fig. 1). These
devices are convenient for making inboard or outboard
amplifiers when you need some additional audio punch.
Most will drive 8- and 16-ohm speakers. For QRP work
they can be used as a complete speech amplifier/
demodulator for a-m, ssb, and fm. A modulation transformer can be added to match their low-impedanceoutput to the transmitter. At the QRPP level, these ICs can
be used as a single-module class-AB or class-B a-m
modulator.
The RCA CA3131 and CA3132 (fig. 2) are two
audio-power ICs that include preamps, power amplifier,
and integral heatsink. The CA3131 has an internal feedback network that maintains an overall gain of approximately 48 dB. The CA3132 has no feedback network
but has facilities for connecting one externally, depending on specific application. In this case the external feedback network usually connects between terminals 6 and
16. The package i s a 16-pin dual-inline with the four
center pins removed.
fig. 1. Sinclalr I C - 1 2 audio power I C provides u p to 6 watts
power output into an 8-ohm load. Voltage gain is about 250;
input impedance is 250k.
64
january 1976
Power output is 4 watts minimum and is typically 5
watts. Recommended supply voltage i s 24 volts dc. The
load can be either 8 or 16 ohms, with 8 ohms providing
higher output. Zero-signal supply current is only 10 mA
- certainly a favorable attribute for solar- and batterypower applications. Inverting and noninverting inputs
are included. Output is single-ended; minimum input
impedance is 200k but typically 1 megohm.
tlg. 3. Five-watt audio power amplifier based on the R C A CA3131/3132. T h e 1000 p F capacitor marked wlth an asterisk is
required if the input has an open circuit.
A complete schematic including external components
i s shown in fig. 3. The audio signal is applied t o the
noninverting input, terminal 1, through C2. Input biasing i s by R, and RB. RB and C3 filter any ac ripple
from the supply voltage line. As mentioned, the input
impedance i s high; therefore in a practical circuit the
input impedance is largely set by the ohmic value of RA.
Filter capacitor C1, an electrolytic, should be placed
as near as possible t o terminal 10. C6 sets a 46 dB
closed-loop gain point at 200 kHz. C7 ensures equal gain
characteristics on positive and negative signal swings. C9
sets the amplifier low-frequency response.
R1 and R2 are a part of the feedback network and
need only be inserted when the CA3132 i s used. C8
compensates for speaker inductance, with RD limiting
any current surge. Closed-loop gain equals the ratio (R1
+ R2)IRl. The low-frequency 3-dB-down point occurs
when C5 reactance equals the ohmic value of R1.
16. This amplifier has a gain of 12 dB. Included also i s a
limiting amplifier with input at pins 3 and 4 and output
at pins 6 and 7. This amplifier operates up to 30 MHz
and starts limiting with a 100-mV input level. Loopgain
i s about 70 dB. The limiting amplifier can be operated as
AUDIO rUP
OUTPUTS
6 9 1 ~
BIASCOMRa M
REF
I/P
WP
I/ P
LIMITING
AMPLIFIER
INPUTS
MF
RCXLOFF
LIMITING
AMPLIFIER
OUTPUTS
PRODUCT
DETECTOR
INPUTS
fig. 7. Plessey SL624C m u l t i m o d e detector can b e used t o detect
a-m, f m , ssb or C W signals. Practical detector circuits using this
IC are shown i n fig. 8.
a beat-frequency oscillator as in the demodulation of an
ssb signal.
The detector is a double-balanced modulator (like the
Plessey SL640C). The limiting amplifier output is
applied to the detector. The detector output connects to
the audio gain control stage input. This gain can be regu-
operated as a crystal oscillator. I t s output i s applied to
the detector. Note the external crystal and the connection t o pins 6 and 7. The sideband signal to be demodulated is applied through a coupling capacitor to pin 8.
After passing through the gain control stage, the recovered audio is removed at pin 12 and applied through
the 0.1 pF capacitor to the audio amplifier input
through pin 1. Audio can be taken at either pin 15 or
16. The signal input requirement is 50 mV maximum,
but good performance at a lower audio level can be
obtained with an input as low as 5 mV.
In the synchronous detection of an a-m signal, input
is applied to the detector through pin 8. Signal is also
applied into the limiting amplifier through pin 3. In the
limiting amplifier, the carrier i s separated from the
modulation and i s used to generate a demodulating
carrier component, which is applied t o the detector and
used to demodulate the incoming a-m signal. Adequate
signal must be applied to permit limiting during modulation troughs to avoid distortion. The input signal should
be 5 to 50 mV. An external agc system is recommended
for this detection mode.
In f m detection, the signal is applied t o the limiting
amplifier input at pin 3, then through a phase-shift network to the detector input. Also the quadrature component is applied t o the detector input through pins 8 and
9. Note the resonant circuit C1-L1. The detector output
is proportional to the relative phase of the two inputs,
with the quadrature component (which does not devi-
AF +lZV
OUTPUT
AF
OUTPUT
t
TO
+I2'
t
DIRECTLY OR V l I MUTE
SYSTEM I S W R O P R I I T E
L
h
V
'7
INPUT
@
J
SELF-OSCILLATING
SSB DETECTOR
@
F M QUADRATURE DETECTOR
SYNCHRONOUS A - M DETECTOR
fig. 8. Practical detector circuits using t h e PlesSey 6 2 4 C include a self-oscillating ssb detector (A).
f m quadrature detector ( 6 ) .and synchronous a-m detector (C).
lated with a control voltage at pin 13. Audio output i s
removed from the gain stage and made available at pin
12. I f desired, the output can be muted by connecting
pin 13 to ground with a switch or electronically with a
squelch circuit.
Practical detector circuits are given in fig. 8. In the
sideband demodulation mode, the limiting amplifier i s
66
january 1976
ate) serving as a reference phase. The recommended input signal should be at least 200 p V , although demodulation occurs with an input signal as low as 100 pV. The
only adjustment required i s that of the phase-shift circuit. An external squelch circuit i s used t o reduce highlevel noise when no signal i s being received.
ham radio
I
DATA TONE ENCODERS
DATA TONE
TO DIAL PULSE
CONVERTER
SOLID STATE CRYSTAL CONTROL TONE DECODERS
12 or 16 Data Tone digits
Bell System Compatibility
Easy Installation
Sub-miniature size
Crystal Controlled
Single Tone capability
Low cost
* Ideal for hand held units
Choice of 4 keyboard styles
RF proof
Temperature. -20.
t o 150eF
CMOS IC Encoder
Style A
Style B
Style C
Convert standard 0-9 Data
Tone digits to Bell System
compatible dial pulse code. Completely sollcl state, Includes stateof-the-art Phased Locked Loop a n t ~ . f a l s ~ n Data
g
Tone decoder.
laree caoacitv 64-dieit memorv and s o l ~ dstate oulsine. Starts d ~ a l I n c o n fl;st 16comlnE d ~ g ~~t . k o wall
r not
~ hechrrle Gngested due
to rapld succession of lncomlng d ~ g ~ tCancel
s
and redlal funct~on.
and # digots are decoded-and provided for remote control
purposes. Available as p.c. board or rack mounting.
DPC-121
P.C. Board
$195.00
DPC-121R
Rack Mount
$285.00
ANTI-FALSING
DATA TONE
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Style D
SELF-CONTAINED KEYBOARD ENCODERS
Complete 12 or 16 digit Data Tone keyboard encoders for mount.
ing directly t o side of hand held transceivers. All electronics
included WITHIN keyboard. nothing t o add inside of transceiver.
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DTM ...................................................................................................................... $49.50
SUB-MINIATURE DATA TONE ENCODER AND KEYBOARD
Data Tone encoder for mounting INSIDE hand-held transceiver.
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SME ........................................................................................................................
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DO IT YOURSELF ENCODERS
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Now buy all the major parts
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complete set of application notes. schematics and instructions.
Keyboard, your choice of keyboard style
$8.50
Digital D. T. Encoder with 1-MHz HC-6 Crystal ..................... $12.50
Digital D. T. Encoder with 1-MHz Slim HC-6 Crystal .......... $13.50
P.C. board 0.8" x 1.2'' .................................................................................... $2.50
All resistors, capacitors, and P.C. board ............................................FREE
(With purchase of keyboard, encoder and crystal)
Now. a true anti-faking decoder/receiver. Virtually immune to high noise or audio
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board or 19" rack.
TTD-126-12
12 digit
P.C. $149.95
Rack $219.95
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TTD-12616
16 digit
P.C. $ 169.95
REPEATER
AUTO PATCH
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It's complete
a single
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Patch f a c ~ l ~ t yAll
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AUTOMATIC DATA TONE
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easy installation. Compatible with most radio equipment. Available
with keyboard for manual dialing of numbers. Manual operation
provides auton~aticPTT operation with 1 % second transmitter hold.
AD6
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99.50
AMDa
With keiboard 119.50
Factory programming of numbers $7.50.
ume and tone control. Sol~d.state output s w ~ t c h ~ nsaves
g
power.
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with both grid block and sol~d.state clrcultry. Wlth its sode-tone
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TTL Keyer Wired $19.95; Kit $14.95
CMOS Keyer Wired $24.95; Kit $19.95
DELUXE RECEIVER PREAMP
Specially made for both OLD and NEW receivers. The smallest
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DATA TONE PADS
Standard size 12 and 16 digit Data Tone Pads. Automatic P l T
operation with 1v2 second transmitter hold. Self powered via
internal 9V battery. Audio and .PTT outputs. TTP.1 and TTP-2
also has low volume audio monotor for acoustically coupling of
tones to microphone. Zero quiescent current. Operating temper.
ature -20'F
to +15OSF. R. F. proof.
Sh. Wt. 2 Ibs. 79.50
TTP-1 16 digit 311 x 5%" x 1%".
TTP.2 12 digit 3" x 5%" x 1%".
Sh. Wt. 2 Ibs. 59.50
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1 thru 30
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DATA
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january 1976
67
ments
1l
I
microstripline
preamplifiers
Dear HR:
WA6UAM1s article on "Microstrip
Preamplifiers for 1296 MHz,"l with a
few exceptions explained below, i s an
excellent article. Having worked with
stripline for several years, especially in
development of the TI ROS-ESSA antenna matching circuitry, I can attest to
the value of such a practical construction article for the uhfer. It was also
very timely, as more and more amateurs
are starting to use stripline techniques
to build uhf equipment.
However, in the design section of the
article, several unfortunate errors and
contradictions appear in the treatment
of the S-parameter reflection coefficients and impedances, which are confusing and misleading, even to one who
is familiar with S-parameter techniques.
The confusion begins in the first paragraph on page 22, where the author
states that complex impedances are generally shown in polar form, but can be
converted to rectangular form through
use of the Smith chart, as per instructions in the caption of fig. 12. The inference is quite clear that the conversion
intended is between the polar and rectangular forms of an equivalent value
of impedance. However, it is not impedance which is being converted, and
furthermore, the Smith chart cannot
perform this type of conversion. Therefore, the inference is incorrect.
The confusion is compounded in the
1. H . Paul Shuch, WAGUAM, "Microstropline
Preamplifiers for 1296 MHz," ham radio,
April, 1975, page 12.
68
january 1976
next paragraph, where it i s stated that
table 1 lists complex impedances in
both polar and rectangular forms, while
in the table itself both the polar and
rectangular forms are stated to be reflection coefficients. This contradiction
needs clarification, and the statements
emphasize the previous, erroneous inference that the associated values appearing in polar and rectangular form in the
table are numerically equivalent, while
in fact they are not.
The confusion can be easily cleared
up as follows: First, it is evident that
the author is randomly interchanging
reflection coefficient and impedance,
confusing the polar-form reflection coefficient with the polar-form equivalent
of the rectangular-form impedance. The
two are not the same!
Impedance, Z = EII, describes the
relation between voltage and current in
a circuit. Reflection coefficient, p, on
the other hand, is the relationship between two voltages (the reflected and
the incident) in a circuit containing two
impedances at a junction, or two currents in the same circuit:
Accordingly, to clarify the first paragraph on page 22 of WA6UAMfs article,
the phrase "complex impedances in
polar form . . . " is a mistatement which
should be changed to read "complex
reflection coefficients are generally
shown in polar form, which can be converted t o impedance in rectangular notation (R f jX) on a Smith chart as indicated in fig. 12" (after the caption of
fig. 12 is also corrected).
Second, the complex numbers appearing in polar form in table 1 are
reflection coefficients, and the rows
containing the polar-form values should
be so labelled. Third, the complex numbers appearing in rectangular form in
table 1 are the impedances which will
give rise to the accompanying value of
reflection when terminating a line or
source having an impedance of 50 ohms.
In other words, taking an example from
the second HP-25826E column, the
12.5 + j0.5 value i s not the rectangular
equivalent of the polar value 0.61
L17g0, but is the complex impedance
which will yield the complex reflection
coefficient F = 0.61 L178" when the
impedance 12.5 + j0.5 terminates a
50-ohm line or source. The rows containing complex numbers in the rectangular form should therefore be specifically labelled impedance Sl or S22, as
appropriate. Proof that the rectangularform impedance is not equivalent to the
listed polar value i s further shown by
the fact that the polar equivalent of the
impedance 12.5 + j0.5 is actually 12.51
L2.2g0, and not 0.61 L 178".
Fourth, as constructed in figs. 9, 10,
11 and 13, the graphs containing the
and S22 plots should be labelled
Sl
impedance, not "reflection coefficient"
because the only loci-identifying coordinates in the graphs are the resistance
and reactance circles. The S-parameter
graphs in the Hewlett-Packard design
catalog2 from which the figures in the
article were taken contain two sets of
coordinates by which the loci may be
identified: resistance- and reactance-circle
coordinates to identify the loci as impedances, and radial magnitude and angle
coordinates to identify the loci as reflection coefficients. Thus the user could
use whichever set of coordinates he desired to read the loci as impedances or
reflection coefficients.
It i s apparent in unravelling a l l this
confusion that a misunderstanding also
exists concerning the basic functions of
the Smith chart. The function which the
Smith chart is really performing in fig.
12 is the conversion from the complex
2. "Diode and Transistor Designers Catalog,"
Hewlett-Packard, May, 1974.
10 on all
orders o r r 55.00
reflection coefficient in the polar form
t o the normalized impedance in the
rectangular form. The magnitude
(radius) and angle 0.8 L-50' in fig. 12
define a specific point in reflectioncoefficient coordinates of the chart,
while normalized impedance is found a t
this same point where the r and x impedance coordinates of 0.6 and 2.0 intersect, respectively. It cannot be emphasized too strongly that the chart is not
converting impedance in the polar form
to i t s equivalent impedance in the rectangular form.
Po la r-to-rectangular conversion of
equivalent impedances is relatively sirnple to calculate using the Pythagorean
theorem. However, conversions between
reflection coefficient and impedance are
more difficult to calculate, hence the
Smith chart is used to simplify reflect i on-to-impedance conversions. As a
point of interest, polar-to-rectangular
impedance conversions can be performed with an overlay combination of
Smith and Carter charts having the same
diameters (the Carter chart has impedance coordinates arranged to identify
impedance in polar form). With the
Smith-Carter overlay the user may enter
the Smith chart in rectangular form and
the corresponding point on the Carter
chart is the polar-form equivalent. As a
further point of interest, here is the expression for calculating the conversion
from a complex reflection coefficient p
to normalized impedance:
- .,\"
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Going in the opposite direction, to determine the reflection set up by a given
complex impedance loading a line of
impedance Z, we have
..
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restrictions depending on the frequency band
selected).
Top quality components used throughout and
all ICs mounted in sockets for easy servicing.
A l l synthesizers are supplled with connecting
hardware and impedance converters or buffers
that plug into your crystal locket.
Vanguard frequency syntheslzen are custom programmed to your requirements In 1 day from
stock units starting as low as $129.95 for transm i t synthesizers and 5139.95 f w receive synthesizers. Add $20.00 for any synthesizer for 5 kHz
steps instead of 10 kHz steps and add 510.00 for
any tuning range over 10 MHz. Maximum tuning
range available is 40 MHz but cannot be programmed over 159.995 MHz on transmit or 169.995
MHz on receive (except on spccial orders) unless
the 1-1 is greater than 10.7 MHz and uses low
side injection. Tuning range in all cases must be
in decades starting wlih 0 (i.e. - 140.000
149.995 etc.). The output frqumcy can be
matched to any crystal formula. Just give us the
crystal formula (available from your instruction
manual) and we'll do the rest. M'e may r q u i r e
a deposlt for odd.ball formulas. On pick-up orders
please call first so we can have your unit ready.
-
C a l l 212-468-2720 between 9:00 a m a n d 4:00 pm
Monday through Friday
VANGUARD lABS
196-23 JAMAICA AVE.
HOLLIS, N. Y. 11423
-
Full color. 40" x 28".
WORLD PREFIX MAP
shows p r e f ~ x e so n each country . . DX zones.
time zones, cities, cross referenced tables
.
$1.25
RADIO AMATEURS GREAT CIRCLE CHART OF
f r o m the center of the U n ~ t e d
THE WORLD
States' Full color, 30" x 25". Ilsttng Great Clrcle bearlngs In degrees for SIX m a j o r U S. cltles:
Boston. Washtngton. D C . M l a m ~ . Seattle. Sari
Franc~sco8. Los Angeles
$1.25
-
lLearn
the t r u t h about your antenna.
lF i n d
its resonant frequency.
lF i n d
R a n d X otf-resonance
lIndependent
R 6 X dials greatly s i m p l i f y
tunlng beams, dipoles, quads.
lConnect
t o antenna a n d t o receiver. Tune
recetver t o dew-ed frequency. Listen t o loud
notse. T u r n R and X dials for null. Read R
d ~ r e c ft r o m dial. X d i a l tells i t antenna is too
long ( X L ) , too short ( X C l , o r on frequency
(X=Ol.
lCompact.
lSimple
lightweight, battery operated.
t o use. Self contained.
lBroadband
lF r e e
1.100 MHz.
brochure on request.
lOrder
direct. $39.95 PPD U.S. 6 Canada
(addsales tax i n Calif.)
RADIO AMATEURS MAP OF NORTH AMERICA!
Full color. 30" x 25" - lncludes Central Ameraca a n d the C a r ~ b b e a nt o the equator, s h o w ~ n g
call areas. zone boundar~es, p r e f ~ x e sand tome
zones. FCC frequency chart, plus useful tnformatoon on each of the 50 U n ~ t e dStates and other
Countrtes
$1.25
WORLD ATLAS - Only atlas c o r n p ~ l e dfor r a d ~ o
amateurs Packed wtth world.w~de lnformatlan
tncludes 1 1 maps, In 4 colors w ~ t h zone
boundaries and country preflxes o n each map.
Also ~ n c l u d e s a polar prolectlon m a p of t h e
a comworld plus a m a p of the Antarctica
plete set of m a p s of the world. 20 pages. Stze
8 % ' x 12"
$2.50
-
-
II
I
Complete reference library of m a p s
as llsted above
- set$3.75
of 4
See your favorite dealer o r order direct.
Mail orders piease include 7% per order
for postage and handling.
RAOIO AMATEUR
Lake Bluff. 111.60044
january 1976
r
r,
W2DU has raised a valid point with
regard to the rather loose terminology
which I used in my recent article, and I
concede that reflection coefficient and
impedance are not synonomous, although they are related.
Several readers have questioned my
failure to consider the transistor's transfer coefficient in calculating the matching networks. Actually, my simplistic
design method, which ignores S12 in
particular, results in a minute matching
error which may be compensated by adjusting the trimmer capacitors at the input and output of the preamplifier.
For the benefit of those readers who
have inquired about Rollett's stability
factor, I should mention that K calculates to greater than unity for all transistor/bias combinations presented in the
original article so the amplifiers are unconditionally stable. Nevertheless. I w u tion the builder to treat them as though
they were not. That is, do not apply
power until the amplifier is properly
terminated in an antenna (or dummy
load) and a converter
H. Paul Shuch, WAGUAM
sgecellb~~k~~.
Dept. E 925 Sknvood Drive
70
Two additional errors of lesser importance are, first, on page 25 a t the
beginning of column 2, the shunt equivalent value of the series impedance 40 +
j25 ohms should be changed from 34.8
+j55.6 ohms, to read 55.6 + j89 ohms.
And second, the NEC V021 column
of table 1, the reactance -j38.5 in the
parallel-circuit input impedance should
be changed t o indicate a positive
reactance.
As a final point of interest, in 1953
the American Standards Association
(ASA) adopted the Greek letter rho, p
as the symbol t o represent reflection coefficient, and many textbook and
periodical publishers, as well as manufacturers of S-parameter measuring instrumentation, conformed. Prior to
1953, p was often used to indicate swr,
and k were used interwhile gamma,
changeably to represent reflection. It
would be interesting to know why the
people a t Hewlett-Packardwho produce
solid-state components continue to use
while those who produce the instruction manuals for their impedance and S
parameter measuring equipment are using P.
Walt Maxwell, W2DU
Dayton, New Jersey
1
Dear HR:
A program, written for the HewlettPackard HP-65 programmable calculator
is available for computing both azimuthal and elevation coordinates for
tracking either OSCAR 6 or 7. Once the
satellite orbital data and individual station positional coordinates are inputed
and stored, the routine will compute az/
el antenna pointing coordinates for any
number of arbitrary, specified times
following the ascending node. Azlel coordinates computed with this routine
for both ascending and descending
passes agree favorably with the results
of a FORTRAN program run on a
CDC-3800 computer and with actual
observed satellite trajectories. The program can be stored on a single HP-65
magnetic card. Documented copies of
the program will be forwarded upon request and receipt of a self-addressed,
stamped envelope; if a blank magnetic
card is included with the request, a copy
of the program itself will be sent.
Earl F. Skelton, WA3THD
Washington, DC
K I T INCLUDES
6
L E D H w r l o u l r iFND 70 7 5 I" i
1 - MM5314 Clock Chop 124 ptnl
INSTRUCTIONS
GUARANTEE0 COMPONENTS
ORDER KIT +850
A N INCREDIBLE VALUE!
(Factory Prime)
MONEY BACK GUARANTEE
- Oaodes
550 or 60 Hz OPERATION
9.- Res~stoo
Printed Circuit Board for above (etched & drilled Fiberglass) ................................... $2.95
Transformer for above (7-10V AC) ...........................................................................$1.50
Plexiglas Cabinet II, Red Chassis, White Case,
::;,'Em
II II
- -
I
~-
-
I
KIT ft7001-C SAME AS # 7 0 0 1 - 8 BUT HAS DIFFERENT LEDs. USES 4 DL-747
63. DIGITS .4 I MAN-7 .3,, DIGITS FOR SECONDS. COMPLETE KIT, Less Case.
GREAT FOR
CLOCK KITS.
W h ~ t e Plexiglas Case
61/*'WIDE
3"
HIGH
Spec~fyRED or GRAY
5112'' DEEP
Plex~glasChassls
Chass~s Serves As Bezel To Increase Contrast of Digital
D~splays. Use Gray With Any Color - Red With Red
Displays Only (Red LED'S with Red Chassis Brightest)
CABINET I/
/
[q)
I
$6.95 ea.
PLEXIGLAS FOR DIGITAL BEZELS
759! ea'
Gray or Red Filter
or 6/$3.50
3" x 6" x Y8'f Approx. Size
lower telephone rates
Dear HR:
I am sure many of the readers of ham
radio have seen the recent ads run by
the telephone company depicting the
new, low longdistance rates. For the
minimum of one minute for 56d (at
times, even less, depending on the distance) one may call coast to coast. In
the evenings, from Sunday to Friday, 8
pm to 11 pm, a one-minute telephone
call costs 36$ or less. For nights and
from 11 Dm to 8
weekends. everv. niaht
"
am and ~aturdaysand Sundays, the first
minute is only 22#.
I t occurs to me that many hams who
wish to communicate with another ham
anywhere in the U.S., may alert the
other party by placing a one-minute
call. which would be all the time necessary to convey information as to frequency and a scheduled time. Previously, minimum rates were for 3 minutes and at triple the price. It's a good
point to keep in mind when wishing to
get another station on the air.
David Greene, W21AO
West Orange, New Jersey
2102-1
lK
RAM
GREAT FOR
CLOCK
KITS.SMALLER
(Ideal for
Ktt ::a50 above
WIDE
All PIe~~gless
Red Chassis,
5lh" DEEP
#Wh~teCase.
Red Chass~sSt& h f s e z e l To Increase Contrast of
LED Displays.
is..('.
$5.95 ea.
- 6 or more $4.95 ea.
I
XTAL TIME BASE KIT for Clock-CalendarAlarm Kit
Uses 100.800 KHz xtal. Can be used
with #7001 Kits only.
$9.95
25 AMP FULL WAVE
BRIDGE 100 plv
LTD. QW.
MAN-7
$1.95 ea.
$3.95 or .95 ea., 10/$8.50. 100/$79
&$$$
3/$5.00
10/$37
In Sealed Factow Pk=.
r
1
CABINET
11 <?I
HIGH
21 2 "
4l 2 ' ,
FACTORY PRIME
MICROPROCESSORS $9.95 ea.
8008
$42.95
II
.3"RED 7-SEG. LED
NOW - SEE MORSE CODE DISPLAYED - A
AUTOMATICALLY - AT SELECTED SPEED - A
One easv connection from your speaker to
the Alpha-Numer~c Display of your Code
Reader CR-101. Displays all letters, numbers, punctuation. Operating speed 55 0 WPM. Easy to use teaching aide.
Han~ d i
ersons
large
skillIs.
l?E€D
- $225.00. C R - 1 0 1 ~has smaller .
rea out TUTT) interfi
ty
- vides CR, LF, figures and letters automatically - $85.00. 6 Month Guarantee
all Parts and Labor.
A
f'
A
ATRONICS BOX 77, ESCONDIDO, CA 92025,
january 1976
71
tebook
i
versatile audio oscillator
The frequency of oscillation is essentially independent of the B1 supply
voltage and is determined by:
Here's a versatile audio oscillator
which can be put to many uses including an audible logic indicator, sidetone
oscillator, code-practice oscillator,
square-wave signal generator and many
others.
In the circuit of fig. 1 transistors
Q2 and Q3 are arranged as a basic collector-coupled astable multivibrator;
power is taken from the collector of
f=-
1
0.69(C1 - R 5 + ~ 2 . x )
If R 4 = R 5 and C1 = C2, then the
output will be a symmetrical square
wave. The frequency of oscillation Can
be varied by changing the value of
.05
SPEAKER
ZN697
fig. 1. Versatile audio oscillator circuit which may be used as an automobile headlight indicator.
audible logic indicator, sidetone oscillator or square-wave signal generator. Oscillation frequency
can be varied b y changing R 4 or R5.
Q1 which acts as a switch for Q2 and
03. With S1 closed and S2 open, Q1 is
cut off and the B1 battery potential is
furnished t o Q2-Q3 through R1. With
both S1 and S2 closed, Q1 is saturated
and i t s collector potential drops t o
near ground; therefore, no voltage i s
available for Q2-Q3 and oscillation
ceases.
either R 4 or R 5 or both; however, i f
R 4 and R 5 are not changed a like
amount, output symmetry will be lost.
With the circuit values shown, a 1 0 0 k
pot in series with a 20k resistor could
be substituted for R5.
The oscillator output is taken from
the Q3 collector via C3. The size of C3
has a marked effect on output volume
PROBE
fig. 3. Using the audio oscillator as an audible logic indicator. Oscillator is isolated from the logic
b y op amp U1 which is wired as a Schmitt trigger.
72
january 1976
'
I
1
fig. 2. Slightly more audio output can be obtained from the oscillator of fig. 1 b y using an
audio output transformer.
when a low-impedance load, such as a
speaker, i s used. Values of 2 pF or larger are quite satisfactory for all impedance loads and will furnish ample
audio volume. If only high-impedance
loads are used such as 2k headphones,
a 0.05 pF disc capacitor will provide
adequate audio coupling. If a better
impedance match and slightly more
volume are desired, an audio output
transformer may be used (fig. 2).
When used as an automobile headlight reminder (with a negative-ground
car) connect the circuit as follows:
IGNITION
SWITCH
DIMMER
SPEAKER
PANEL LIGHTS
Power for the oscillator i s derived
from the dashboard panel lights, which
are turned on simultaneously with
either the parking lights or headlights.
If the ignition key is turned on, Q1
saturates and disables 02-03; with the
ignition off Q1 is cut off and the 0 1
collector voltage rises, providing power
to 02-Q3. The audio output may be
connected directly t o the car radio
speaker voice coil high side without
affecting car radio operation.
By connecting the oscillator port 1
to the panel lights the oscillator may,
if desired, be purposely disabled with
I
The Transceiver
youu expect
the ignition off and lights on merely
by dimming the dashboard panel
lights. Current drain of the oscillator
on the car battery is virtually negligible. The oscillator may be permanently wired to and powered from the
existing dashboard controls without
requiring additional controls or
switches.
The entire printed-circuit board can
be wrapped with electrical insulating
tape and strapped to any convenient location under the dashboard out of sight,
or mounted in a small Minibox. For connection to the car's electrical system,
the proper leads can be easily located
with a voltmeter or VOM; once located, simply splice in the appropriate
oscillator lead, solder, and wrap the
joint with electrical tape.
When used as a sidetone oscillator
or code practice oscillator, connect as
foltows:
UEIEO GROVWO
is ready-now!
a
NEYEO I ) +
In the above configurations, Q1 and
R 2 may be eliminated, if desired. The
entire oscillator may be constructed
on a PC board measuring only 1-118
by 314 inch (29 by 19mm) i f TO-92
transistors are used. For TO-5 transistors the board i s slightly larger, 1% by
718 inch (32 by 22mm). Height of the
board with components is about %
inch (13mm). Since the circuit is very
simple, point-to-point wiring on terminal strips is another alternative if automobile installation is not intended.
Layout of components i s not critical, nor i s selection of 01423. Although 2N697s are specified, unmarked npn transistors from surplus
From the company that revolutionized hf ham radio by giving you the first all.solid-state low and medium
power equipment, comes the entirely new TRITON IV, a transceiver that is truly ahead of its time. The fore.
runner Triton If gave you such operating and technical features as instant transmitter tune, full break-in, excellent SSB quality, superb receiver performance, pulsed crystal calibrator, built-in SWR indicator, a highly selective CW filter and efficient home, portable and mobile operation from non-aging 12 VDC transistors.
Now - the TRITON IV gives you all of these - and more. A new push-pull final amplifier with the latest
gold metalized. Zener protected transistors, operating at 200 input watts on all hf bands 3.5 through 29.7 MHz.
Plus a new crystal heterodyne VFO for improved short and long term frequency stability and uniform 1 kHz readout resolution, even on ten meters.
Unsurpassed selectivity is yours with the new eight pole i.f. crystal filter, and improved spurious rejection
results from the new lC double balanced mixer.
The benefits of ALC now extend to output powers less than full rating with a front panel threshold control.
When driving linears that require less than maximum available power from the TRITON, or when propagation cow
ditions permit reliable contacts at reduced power levefs, ALC will hold your output to the desired level.
Many small circuit improvements throughout, taken collectively, add more performance and quality pluses
- such things as individual temperature compensated integrated circuit voltage regulators for final bias control
and VFO supply. And toroid inductances in the ten and fifteen meter low pass filters, LED indicators for offset
tuning and ALC threshold, accessory socket for added flexibility. and sepuentially keyed mute, AGC and transmitter circuits for even better shaped and For more information about me new
TRITON, as we11 as me full line of
clickless CW.
accessories that will be available
And to top it all off, the highly desirable case aeometrv has been main.
tained, but it has a handsome new look. Bold lettering on anetched aluminum
front panel and textured black sides and top make the TRITON 1V look as
sharp as it performs.
There is nothing like a TRITON IV for reliability, features, value and just
pure fun. And - best of all -you do not have to wait until 1980 to own one.
TRITON IV $699.00
See YOUr
Or w r i t e .
1r.7r
TE N-7 EC
SEVIERVILLE, lENNESSEE 37882
EXPORT 5715 LINCOLN AVE
CHlCAdO
ILLINOIS
kOfi16
FAST SCAN AMATEUR TELEVISION EQUIPMENT
SOLID STATE
BROADCAST QUALITY
PERFORMANCE
FOR TECHNICAL DATA
AND PRICING,
WRITE TO:
I
A
.+
-.2
w
-
-',-P.-
?..
I
AX-10 TRANSMITTER
E- r i
--
AM-1A RCVR MODEM
11
with TELREX Professionally Engineered
(1
"BALANCED-PATTERN "PERFECT-MATCH"
11
11
'*BEAMED-POWER
Antenna Systems
The design, craftsmanship and
technical excellence of Telrex Communication Antennas.
have made them the standard of
comparison throughout the world!
Every Telrex antenna model is
engineered, precision machined,
tuned and matched, then calibrated
for easy and correct assembly at
your site for repetition of our
specifications without 'cut and
try' and endless experimentation.
--
Send for latest free Amateur Catalog
Phone:
Also: Rotator-Selsyn-Indicator
Systems, Inverted-V-Kits,
"Baluns," 12-Conductor Control Cable
WANTED
FOR CASH
-
"
201-775-7252
I . .
h,
,"I,.
iii
, 1 1 &
1
g
*-%
\
L d e- , -.
R1051 or T827
ARC-51 Transceiver
(Also known as CU1658
and CU1669)
Highest n,,,rhazrrl
price paid forPhnnr
these units.
Ted-
. - . .-
- . - ..- - - - .
. ..- ..-
.- -
.
~ 2 ~ ~ ~ ~ c o We
l l ewill
c t trade
.
for
new amateur gear. GRC106 and
PRC74 also required. See H R last
Issue for other equipment required.
ARC-51 Control Box
618-T Transceiver
(also known a s MRC95.
ARC94. ARC102, or VC102
THE TED DAMES CO.
308 Hickory Street
(201) 998-4246
Arlington. N. J. 07032
Evening (201) 998-6475
VHF FREQUENCY COUNTER
5 DIGIT LED DISPLAY
10 Hz TO ,230
< 200
MHz
M V SENSITIVITY
FACTORY DIRECT SALES
$19500
ASSEMBLED OR KIT
II WEBER Electronics
KIT PRICE $149.95
74
january 1976
WIRED & TESTED
+ $3.50 POSTAGE
AND HANDLING
Elmcrest Terrace, Norwalk, CT 06850
computer boards were used for the
fifteen or so automobile headlight
units I've built so far; all worked as
intended the first time.
For the IC enthusiast, Q1-Q3 can
be individual transistors in an array
such as the CA3018 (TO-5 case) or the
CA3046 (14-pin DIP). However, if ICs
are used, a 1N914 diode will be necessary from the Q1 collector t o R3;
otherwise, it may be omitted.
When the oscillator is used as an
audible logic indicator, or audible
logic-state indicator, additional isolation of the oscillator from the probed
circuit element should be provided to
prevent loading the logic circuit. A
high-impedance input opamp is ideal
for this application. Fig. 3 shows the
circuit.
The opamp is configured as a poorman's Schmitt trigger; i.e., a fairly
rapid output transition occurs at a
specific preset input voltage level by
omitting the usual feedback resistor
between pins 6 and 2. The opamp acts
simply as a very-high-input-impedance
inverter with virtually no hysteresis
about the preset transition reference
voltage level appearing at the noninverting input, pin 3. This reference
voltage is easily provided by the resistive divider network R8-R9.
Since a TTL-compatible logic probe
was desired, the reference level was set
for +1.6 volts. The zero logic state
maximum voltage for the SN7400
series TTL ICs is about 0.8 volt; the
minimum 1 logic level is about +2.4
volts. The +1.6 volt reference level i s
an arbitrary selection between the two
TTL logic levels. When the probe input
voltage is below +1.6 volt the op-amp
output is approximately 10.5 volts,
which saturates Q1 and disables
Q2-Q3; when the probe voltage is
above +1.6 volt, the U1 output is
about 2 volts, which cuts off Q1, and
power is supplied t o Q2-Q3. R7 must
be selected to allow cutoff of Q1 when
the U1 output is low, and permit saturation of Q1 when the U1 output is
high.
These are just a few of the possible
applications for this handy and inexpensive oscillator; further applications
are left t o the ingenuity and imagination of the reader.
Howard F. Batie, W B B X
,
@
I
2-meter FM. 100
channels. 30 watts
(incl. 146.94 MHz)
(
2-meter FM. 100
channels. 30 watts
I (Incl 146.94 MHz)
en-100
FM.
I O;ll/r-meter
W"~
;,nesl.
$309.95
I was
(Incl 223.5 MHz)
i1
HAND-HELD
I
GTX-2
2-meter FM, 10
I channels.
30 watts
$299 95
II was
(Incl 146 94 MHz)
CHECK THESE FEATURES:
All Metal Case
American Made
Accepts standard plug-in
crystals
Features 10.7 MHz crystal
filter
Trimmer caps on TX and RX
crystals
3.5 watts output
Battery holder accepts AA
regular, alkaline or nicad cells
Mini Handheld measures
8" high x 2.625" wide
x 1.28lW deep
Rubber ducky antenna,
Wrist safety-carrying-strap
included
6 Channels
Factory-direct to You
iI
II
iI
'
I
Nicad Battery Pack
Charger for GTX-1 battery pack
Leather carrying case
TE Ill Tone Encoder for auto
patch
.
GTX-600
6-meter FM. 100
channels. 35 watts
was $309.95
(Incl 52 525 MHz)
- - -
I
em-,
2-Meter FM. 6Channel, 3 5 Watts
I
I
I
I
GTX-1
Accessories Available:
6TX-10
2-meter FM.
10 channels.
2 Meter 6 channel
Hand-Held
(without encoder)
GTX-IT
with Bullt-In
Tone Encoder
I
I
1
I
1
I
I
j24995 529995 (.I
PSI-11 Battery Pack (with
charger)
@ $109.95 $
ARX-2 2-M Base Antenna
@ $29.95 $
Lambda14 2 - M Trunk Antenna
@ $29.95 $
nTE-I
Tone
~ncoderTad
u
@ $59.95 $
TE-ll Tone Encoder Pad
6)$49.95 tPSI-9 Port. Power package
(less batteries) @ $29.95 $
PS-1 AC Power Supply
@ $69.95 $
and the following standard crystals
@ $4.50 each: . ................$
Non-standard crystals
@ $6.50 each: ................... $
I
I
I
I
II
-
I
-
For factory crystal installation a d d $8.50
oer transceiver.
'
Sub-Total: $
$
8
I(allow
weeks TOTAL:
.(delivery.)
I
(minimum order $12.00)
IN residents add 4% sales tax:
rendents add 6%sales tar:)$-A l l orders shipped post-paid
c.
within continental
U.S.
AMATEUR CALL
CITY
General Aviation Electronics, hc.,
4141 Kingman Drive,
Indianapolis,Indiana 46226
Area 317-546-1111
n Certified ChecklMonev Order
I
I
I
1
-
---STATE&ZIP
t
l Personal Check
n C.O.D.
-
Include 20% Down
Note: Orders accompanied by personal checks will require about two weeks t o process.
20% Down Payment Enclosed. Charge Balance To:
BankArnericard #
Master Charge #
Expires
I
I
i
I
I
I
I
I
I
I
I
Expires
1
Interbank #
L--I.-------cLIPouTAN~oRDERNOW-----II----
More Details?CHECK-OFF Page 102
I
I
I
I
I
I
1
january 1976
7
H 6
75
products
two-meter
f m transceiver
The new products announcement of
Standard's new Horizon 2, a 12-channel,
25-watt vhf fm transceiver, in the November issue of ham radio contained a
typographical error: the correct amateur
price is $295.00 Contact your local
dealer for further details.
vhf fm
power amplifiers
The new M-Tech P50A1 vhf power
amplifier is designed specifically for
amateurs with low power two-meter fm
transceivers or hand-held units - 1 t o 3
watts input will deliver 40 t o 65 watts
output. The P50A1 is designed for operation with a 13.6-volt power supply (8
amps) and is rated for an 85% duty
cycle. The unit includes COR switching
with an LED indicator and a spurious
outout filter. and is oriced at $139 ~ o s t paid.
Other 144-MHz fm power amplifiers
in the M-Tech line include the P15A1
(1-3 watts input, 12-25 watts output,
100% duty cycle) which features solidstate switching and is priced at $59; the
P50A10C (2-18 watts input, 14-60
watts output, 100% duty cycle), $98;
the P100A10 (5-12 watts input, 60-100
watts output, 85% duty cycle), $198;
the P100A20 (18-35 watts input,
80-100 watts output, 85% duty cycle),
$155; and the P100A5 (2-5 watts input,
76
january 1976
40-100 watts output, 85% duty cycle),
$198. All amplifiers are vswr protected
for any load, include a reverse current
protection circuit, use microstrip inductors for stability, and carry a l-year factory warranty. All amplifiers except the
P15A1 feature COR switching with an
LED indicator and a spurious output
filter.
M-Tech also manufactures two solidstate power amplifiers for the 220-MHz
band, the P30A1-220 (1-3 watts input,
30-45 watts output, 85% duty cycle)
and the P30A10-220 (2-18 watts input,
12-40 watts output, 100% duty cycle).
Both of these units feature COR switching with LED indicator.
For more information on M-Tech's
Quality Emphasis Line of vhf-fm power
amplifiers, write to M-Tech Engineering,
Inc., Box C, Springfield, Virginia 22151,
or use check-off on page 102.
eter and one inch deep (5x2.5cm), and
weighs only three ounces (859).
The RCA WV-548A HiILow power
line monitor i s priced at $9.95. For
additional information on RCA Electronic Instruments contact RCA Distributor and Special Products Division,
2000 Clements Bridge Road, Deptford,
New Jersey 08096, or use check-off on
page 102.
test equipment
random-wire
antenna tuner
If you like portable operation and
want to get on the air with the least
amount of trouble, a random-length
wire antenna is hard to beat. You'll
need a tuner for the random wire, and
SST Electronics has the answer with the
SST T-1. The SST T-1 tunes from 80
through 10 meters and handles 200
watts. It matches the low-impedance
output of your transmitter and the lowimpedance input of your receiver to the
high impedance of a random-length wire
antenna. Simple and foolproof design
features an LC circuit and neon-bulb
tune-up indicator. It's compact, only 3
by 4% by 2-3/8 inches (7.6 by 1lxlcm).
The SST T-1 sells for $24.95 postpaid
and is guaranteed for 90 days against
defects in parts and workmanship. For
more information, write SST Electronics, P. 0. Box 1, Lawndale, California
90260, or use check-off on page 102.
power-line monitor
A new compact high-low power-line
monitor with a convenient swivel plug
for use directly in an ac outlet or
through a standard multi-socket cube is
now available from RCA. This small inexpensive test instrument is an ideal
tool for every amateur's toolbox and
reads from 50 to 150 volts ac (true
rms), 50-60 Hz with a plus or minus 5
per cent accuracy. Circular in shape, the
new monitor is only NO inches in diam-
The 24-page Tucker Electronics Sales
Bulletin lists a wide variety of reconditioned t e s t equipment as well as a dozen
different lines of new instruments. Although the bulletin shown above was released in May, new sales bulletins are
issued periodically. For your copy,
write to Tucker Electronics Company,
Post Office Box 1050, Garland, Texas
75040, or use check-off on page 102.
volt-ohm-milliammeter
The Triplett Corporation has introduced an unconventional type of voltohm-milliammeter that gives the user an
"extra-chance" after misuse . . . and not
a repair bill. This virtually indestructible
test instrument has built-in protection
against accidental high energy overload,
is shock resistant to accidental drops up
to a five foot (1.5m) height, is of modular construction so that it can be easily
and quickly serviced in the field and has
been designed t o the most rigid safety
standards to prevent any hazard of electrical shock to the user. Triplett has
aptly named it the "Extra-Chance"
model 60.
The new vom has no exposed metal
parts, providing complete insulation of
the instrument itself, special test leads
for increased safety and a three-fuse
testing system which greatly reduces fire
and explosion hazard under misuse conditions. Two 48-inch (1.2m) long safety
test leads are supplied and connect to
the control panel by special safety
connectors.
A rugged case molded of black, high
impact thermoplastic material in combination with a ruggedized suspension
meter result in a vom that i s virtually
indestructible from accidental drops up
to a five-foot (1.5m) height. The meter
movement is protected by a diode module; fuses are used for normal overload
conditions. A fuse plus two zener diodes
are used to protect against high energy
fault currents and protect the circuit up
to 1000 volts. A separate, sealed battery
compartment permits easy external access to batteries and fuses without
having to remove other parts of the
instrument.
A single range selector switch is used
for selecting all 33 acldc voltage, ac
output, resistance, dc current and
decibel ranges from -20 to +52 dB
plus the off and test positions. Accuracy
on all dc and resistance ranges is +2 per
cent of full scale; ac accuracy is +3 per
cent of full scale. The Triplett model 60
(catalog number 3145) comes complete
with a one-year parts and labor warrantee, safety test leads, batteries, spare
fuses and instruction manual, and sells
for $90. For additional information,
write to the Triplett Corporation, Department, PR, Bluffton, Ohio 45817, or
use check-off on page 102.
B & K PRECISION
- MODEL 1801 FREQUENCY COUNTER
Frequency Range: 10 Hz to over 60 MHz typical
Sensitivity: 30 mV RMS guaranteed
lnput Z: 1 rneg/25pF
Max lnput Voltage: (peak AC
DC) 200V @ 500 Hz lOOV @ 1 kHz,
50V @ 40 MHz
Internal xtal oscillator time base-treq: 10 MHz Setability: k 1 Hz
Readout: 6 digits with overflow
Power: 105-130V, 60 Hz, 25W max.
Size: 3.31 x 8.69 x 10.5" Wt.: 5.5 Ib.
+
-
PRICE .............................................................................................................
$230.60
Call or write for FREE B & K Catalog.
Call or Write for info on many other lines including Standard, Regency.
Bomar Crystals, etc.
Prepaid Orders accompanied by M.O. or Bank Checks are shipped immediately.
U.P.S. C.O.D. also available if specified.
ORD, MA 02155
Great
New
Turn On
seven-segment
displays
\
MOCO I1 ushers i n a new generation of Morse Code Readers. Its
central processing unit is cornbined w i t h computer programmed
firmware totalling more than
8,000 bits of memory, which perm i t MOCO 11 t o translate standard alpha-numeric Morse Code,
even punctuation automatically.
Simply connect MOCO I1 t o the
speaker leads and then just turn i t
on. No knobs, n o adjustments.
One switch calibration automatically determines and displays
,..-- 0
@-I
sending speed.
ru-"
r:;,
New high-efficiency solid-state numeric displays, as much as five times
brighter than other displays at the same
operating current, are now available
from Hewlett-Packard. At one-fifth the
current, they are equal in brightness to
older displays. Their high brightness
plus their 0.43 inch (1lmm) height
makes them ideal for applications in
high ambient light conditions. Operating
at currents as low as 3 mA, these large
displays become practical for use in battery-poweredportable instruments. They
More Details? CHECK-OFF Page 102
d-w.8."-
rrl-"""
-
---1
Howard Microsystems
introduces MOCO 11, the newest
and most efficient Morse Code
translator in the state
of the art.
MOCO 11 is not a kit. It's
completely assembled and tested,
includes integral power supply,
parallel ASCII and Baudot outputs for existing display units.
PRICE: $199.00
Available as options are a video
display, or a teletype driver w i t h
6 0 ma. loop supplies.
Order from Howard Microsystems, Inc., 6950 France Avenue
South, Minneapolis, M N 55435 (612) 925-2474.
DISPLAY OPTIONS
....... $75.00
....................... $325.00
A. Baudot Drlver/lnterface for T T Y
6. Video Character Display with V H F T V
Modulator..
(Kit..
........................... $175.00)
AII orders - add $2.75 shipDing/handllng
M
HOWARD MICROSYSTEMS, INC.
january 1976
77
Portable Range Booster
.
for HF and
Extend t h e range o f y o u r h a n d
h e l d transceiver w i t h t h i s c o m b i n a t i o n Amplifier/Battery Unit. Dclivers 2 5 w a t t s t o
i t s antenna.
Military Quality
Leather case &
Flexible Antenna
Weight: 3.3 Ibs.
Size: 4%" x 2%"
x 6"
Price: $199.95
Coming Soon! Linear Version at $219.95.
NEW
- NEW - NEW
2 8 4 3 2 M H z S o l i d S t a t e Transceiver
S y s t e m Modules t o b e available soon!
9
No tuning across entire Amateur band.
Full VSWR and reverse voltage protection.
Under 1 dB insertion lass in receive.
1 Year Warranty.
Write for details on particular models.
T h e DX 'J' ANTENNA:
Gold-alod~nedalum~numradiators
Requires n o round l a n e
VSWR typ. 1.3:1 (14g-148 MHz)
Handles 250 watts plus
Weight: 8 02.
144 & 220 MHz Models
Coming Soon - Horizontally polarized models and 440 MHz model.
SPECIAL INTRODUCTORY PRICE $24.95
may also be operated in the strobe mode
at currents up to 60 milliamperes peak.
The HP models 5082-7650, -7660,
and -7670 are red, yellow and green,
common-anode, seven-segment displays
with lefthand decimal point. LED chips
are optically magnified to form evenlylighted segments. For improved on-tooff contrast, the bodies of the displays
are colored to match the appearance of
the unlighted segments.
For more information, contact your
local Hewlett-Packard Sales Office, or
use check-off on page 102.
fet multimeter
Add for shipping & handling ............ .. $2.50
California residents add 6%.
Louis N. Anciaux, WB6NMT
W r i t e n o w o r c o n t a c t nearest dealer. Dealer Inquiries Invited.
SPECIALTY COMMUNICATIONS SYSTEMS
4519 Narragansett Avenue
Louis N. Anciaux
San Diego, Calif. 92107
WB6NMT
Aha, the SECRET of PC
Board success finally revealed.
A perfectly balanced lighting
tool combining magnification
with cool fluorescence. Excellent for fine detail, component assembly, etc. Lens is precision ground and polished.
Regularly $70.00. Now, over
301 discount (only $49.00)
in Callbook. Uses T-9 bulb
(not supplied ).
Include $3.00 U.S. postage, or $4.00
in Canada. $5.00 elsewhere. California Residents include 6%sales tax.
Or send stamped envelope for free
brochure of other incandescent or
fluorescent lamps suitable for all engineers, architects, students, etc.
Mastercharge a n d ~ a n k ~ m e t i c a accepted
rd
D-D ENTERPRISES
Dept. A, P. 0. Box 7776
San Francisco, CA 94119
78
january 1976
10 .CHANNEL
.
10 Second Delay Before Scan Resumes
after Transmit
2 Second Delay Before Scan Resumes
After Signal Loss
Plugs Into Existing Crystal Sockets. Simple
5 Wire Hook-Up Without Major Modification To Radio
Simple Modification For Selective Channel
SCANN 1 0 B 1 0 Channel Scanner
(Wired Only)
$52.50
D l O B D i g i t a l Channel Display $21.75
(Wired Only)
N E T PRICE FOR BOTH ................. $74.25
HR-2B W i t h B o t h Installed ...... $299.99
6T-HR2-3 Crystal Deck (6 m o r e FQ's
i n HR2, HR.2A) .. ........ ..... K i t $11.50
Wired $15.50
A new pocket fet multimeter offering full vtvm ranges and a 10-megohm
input, complete1y protected against
overload, is now available from Hickok.
Packaged in a rugged, pocket-size case
with attached cover the Model 350 provides features which include 1 millivolt
resolution on three easy-to-read mirrored scales plus dB and battery condition, highflow ohms ranges, and true
autopolarity with a polarity indicator.
High impedance fet circuitry permits
vtvm type ranges in this compact unit.
Nine voltage ranges of 0.1 to 1000 volts
and seven highllow ohms ranges from
100 ohms to 100 megohms center scale
make the Model 350 a versatile service
tool. One-year service can be expected
from the two 9-volt transistor radio
batteries. The Model 350 comes complete with two test leads and instruction
manual.
For more information, contact Tom
Hayden, Instrumentation & Controls
Division, Hickok Electrical Instrument
Company, 10514 Dupont Avenue,
Cleveland, Ohio 44108, or use check-off
on page 102.
More Details? CHECK-OFF Page 102
Now".
THEMOBILE
.k ANTENNA.
,
IS
~
Add the amateur radio mobile antenna to the list of things successfully
automated for our increasing comfort.
The Swan Model 742 Triband Mobile, the only automatic amateur radio
antenna, eliminates coil changing, tap adjusting, switch flicking and all
the rest of mobile antenna inconvenience.
Now for the first time ever you just sit behind the wheel and change
from 20 to 40 to 75 meters while your 742 automatically loads itself for
each band-perfectly.
Rated at 500 watts P.E.P., the new antenna is one of a complete line of
advanced amateur radio antennas and antenna accessories by Swan. All
designed to help you put maximum power where you want it.
Model 742 automatic triband mobile antenna. $79.95.
Only from Swan. Where else?
Dealers throughout the world
or order direct from
[email protected]
ELECTRONICS
A cnbsidl{rry of (:ul,,, (.#,rpnn!r~otl
Home Office:
305 Airport Road Oceanside. CA 92054
~
HE FM LEADER
I
. .
ELECTRONICS, I N C . , 7707 Records Street, Indianapolis, Indiana 46226
U.S. Patent
-
The new Low Pass Filter is more than 80 dB down at 41 MHz
and above! This is the third harmonic of 20 meters and the
second harmonic of 15 meters-it's also the I.F. frequency for
TV! The popular TV-1000-LP provides for low power operation on 6 meters and thus cannot roll-off below 52 MHz.
Write for the TV-3300-LP curves.
I
I1
540 Richard St., Miamisburg, Ohio 45342
:?
Special pry-proof hardware
Dealer & Club inquiries invited
Fm
See your Dealer.
For more information please contact:
R. L. DRAKE COMPANY
#3410122
SHUR-LOK w i l l a c c o m m o d a t e a u n i t
w i t h overall dimensions including
m o u n t i n g bracket u p
3%" H i g h
a n d f r o m 4 % " t o 9% Wide.
Prevents access t o rig's m o u n t i n g
N o special tools
hardware
I
@
Phone: (513) 866-2421 Telex: 288-017
1
You spent $200, $300 or $400 to
put your VHF rig in the car. Why
not spend $15 to keep it there!
Order now from National Mfg's. Rep.
for Amateur Radio Use.
PRUlTT ENTERPRISES
WANT TO TRADE BINDERS?
?
.
Got more small sized HAM RADIO Binders than
you can use?
Now with our new large sized magazine we'll
trade anv extra small sizedu(6" x 9") birders for our
new largk sized binders for just $1.00 ($2.00 foreign)
per binder shipping and handling.
Send in any extra binders in new, unused condition still in their original shipping carton along with
the wires and date labels plus $1.00 per binder. We'll
ship you a brand new large binder for each small
one returned.
Hurry though, this offer i s valid only through January 31, 1976.
HAM RADIO
15O/0
GREENVILLE, N H 03048
I
Savings on Gas
A Capacitive Discharge Ignition system absolutely
guaranteed NOT t o interfere with your radios &
equally guaranteed to improve your auto's operation and gas mileage.
6 - D I G I T COUNTERS!
6-Digit Kit
THE TIGER
6-Digit Kit
No rewiring necessary. Engine cannot be damaged
by improper installation. Either of three mcdels
fits any vehicle or stationary engine with 12 volt
negative ground, alternator or generator System.
Uses standard coil & distributor now on your
engine. Dual switch permits motor work or tune-up
with any standard test equipment.
Write for free booklet that not only is the BEST
We have a whole wonderful line of unbelievable counters
starting at $45.95! Drop us a line or give us a call today.
mh
82
Dept. 11, P.O. Box 357 Provo, Utah 84601 (801) 224-3355
january 1976
San Francisco, CA 94119
More Details? CHECK-OFF Page 102
CRYSTAL FILTERS
[email protected]
and
8
9.0 M H z FILTERS
XF9.A
2.5 k H z
XF9-B
2.4 k H z
XF9.C
3.75 k H z
XF9-D
5.0 k H z
XF9-E
12.0 k H z
X F9. M
0.5 k H z
XF9.NB
0.5 k H z
SSB TX
SSB RX
AM
AM
NBFM
CW
CW
DISCRIMINATORS
9.0 M H z CRYSTALS (Hc25/u)
XF900
9000.0 k H z Carrier
XF90 1
8998.5 k H z U S E
XF902
9001.5 k H z L S B
XF903
8993.0 kHz BFO
$31.95
545.45
$48.95
548.95
$48.95
$34.25
$63.95
F-05
9.0 M H z DISCRIMINATORS
XD9-01
z!
5 k H z RTTY $24.10
XD'-02
-C10 kHz N B F M $24.10
XD9-03
& 1 2 k H z N B F M $24.10
$3.80
$3.80
$3.80
$3.80
Exmrt Inquiries Invited
.50
S h i p p i n g 504 p e r f i l t e r
VHF CONVERTERS UHF
:eh
-
-
M M c 50
50-54
28.32
2.5dB
30dB
R F Freq. (MHz) t
I F Freq. t
N.F. (typical)
Nom. Gain
Hc25/u Socket
M M c 144
144-148
28-32
2.8dB
30dB
-
M M c 220
220-224
28-32
3.4dB
26dB
M M c 432
432-436
28-32
3.8dB
28dB
M M c 1296
12961300
28-32
8.5dB
20dB
420-450 MHz
MHz
8 OVER 8
D8 2M
GAIN. REF DIPOLE 12.6 d B
FEED 5 0 9 COAXIAL
543.95
$
-
D8/2M
VERT.
FOR LONGE RANGE
REPEATER ACCESS
G A l N 12.6dB REF DIPOLE
FEED 50!! COAXIAL
$52.70
Antennas FOB Concord.
v i a UPS
0. BOX 1084
INTERNATIONAL, INC.
i2$*Di
connectom
+
l o w N. F. u n i t s o n s ecial order.
+ ~ X e ranges,
r
amateur &commercial,
t o order.
\ A
70/MBM48
G A l N VARIATION ACROSS
B A N D TYP 2 0.5dB
FEED 50!! COAXIAL
S56.75
'I
Pow
;;
c
ANTENNAS
I
K.V.G.
Mass.
1250-1340 MHz
'\
-
1296
LY
1296 M H z LOOP-YAGI
"AIN
+20dBi
FE$- '<o_<COAXIAL
CONCORD, MASS. 01742
U.S.A.
-.-
F A N (MINIATURE MUFFIN
TYPE)
Rotron Mfg
Sprlte Fan 3 1 % "
Square x 1 63"
Reduces Prlnted Clrcull Board Art Work From 2 Hours to 10 Mln
I
Simple as A.B.C.
A. S
I C o~n p a n h a P.C. BO.,~
########
I* .I* DuEL l M LInf
SOCKET
########
*........
....
....
0..
10
*
u* W * D
~ .10
n~n~rcomrt
U-.
C. ttch
l
-
~
3" CRT TUBES
3EP I
socur7
N E W GUARANTEED
$3.95 em.-41510.00
LOEIll
r u ~ u s r o nsocurl
0-.
TO.,*
?
Umr
L L l U U D O Y n *AD
RESIST INK . 95c
per bottle
RESIST PEN 81. 95c
INK PAD ea. $1.15
Etching Containers. 10 for 9%
I
84
.
IC
IC * O C I I T
,
I
*W * D IC
70.5 TU*.l#TOl
B. u.
33 CFM Ball 8earing Whisper
Quiet 14 oz. Great for the small
places! BRAND NEW $9.95 ea.
STEREO PREAMPS
High Quality
Module Type.
wtres easlly In.
to extsllng stea
reo where an
equal~zer pre amp state IS requlred, can be used In mapnetlc cartridges, tape decks, or
heads, low Impedance microphones. etc 12 V power source.
20 to 20 KHZ Frequency response, very sensltlve 3"x4% "x
V8" BRAND NEW WITH SCHEMATIC. LIMITED QUANTITV3 for $2.00
10 for $5.00.
VIDEO PREAMPS
A.C.E. LABORATORIES
P.O. BOX 2366
Indianapolis, Indiana 46206
january 1976
DESOLDERING I R O N
Mfgd. by
leadlng
company (in
U S.A.) in
the soldering tool fleld. These units are
NEW! Slight plating blemish
prevents factory from marketing.
A 40 watt unit which mav be
aqed
.... for
. solderinn as well as
desolderlng WE ~UARANTEE!!
ORIGINALLY SELLS FOR $16.95
A.C.E. PRICE $8.95 each
(lhnited inventory)
More Details? CHECK-OFF Page 102
DIGITAL DATA RECORDER
for
Computer or Teletype Use
Up to 2400 Baud
Uses the industry standard tape saturation method t o beat all FSK systems ten t o one.
N o modems or FSK decoders required. Loads 8K of memory i n 34 seconds. This recorder
enables you t o back u p your computer b y loading and dumping programs and data fast as
you go, thus enabling you t o
get by with less memory. Great
for small business bookkeeping. Imagine! A year's books
o n one cassette.
Thousands are i n use i n colleges and businesses all over
the country. This new version
is ideal for instructional, amateur, hobby and small business use. Ideal for use by servicemen t o load test programs. Comes complete with prerecorded 8080 software program used t o test the units as they are produced. (Monitor)
I
SPECIFICATIONS:
A. Recording Mode: Tape saturation binary.
This i s not an FSK or Home type recorder.
No voice capability. No modem.
B. Two channels (1) clock, (2) Data. Or two
data channels providing four (4) tracks on
the cassette. Can also be used for NRZ,
Bi-Phase, etc.
C. Inputs: Two (2). Will accept TTY, TTL or
RS 232 digital.
D. Outputs: Two (2). Board changeable from
TTY, RS232 or TTL digital.
E. Erase: Erases while recording one track at
a time. Record new data on one track and
preserve three or record on two and preserve two.
F. Compatability: Will interface any computer
using a UART or PIA board. (Altair, Sphere,
M6800 etc.)
G. Other Data: 110 V - (50-60) Hz; 2 Watts
total; UL listed #955D; three wire line cord;
on/off switch; audio, meter and light operation monitors. Remote control of motor
optional. Four foot, seven conductor remoting cable provided.
H. Warrantee: 90 days. All units tested at 110
and 2400 baud before shipment. Test cassette with 8080 software program included.
This cassette was recorded and played back
during quality control.
COMING NEXT MONTH - IN KIT FORM
board
* Hexadecimal Keyboard - Load programs
direct from keyboards' 16 keys and verifying
display. Does not use Computer I/O.
* 1/0 for use with Computer Aid or other
digital recorders. Variable baud rate selectable on externally located unit by one knob.
Can load computer or accept dumps without software. Turnkey Operation. For any
8 bit computer.
* Record/Playback Amplifier
Expanded version of our Computer Aid
for use with your own desk (cassette
or reel to reel). Go to 9600 baud on reel
to reel. Digital in, digital out, serial format.
* Interested in these? Send your name and
address for brochure when released.
(EDUCASSETTE i s our registered TradeMark)
Fill out form and send check or money order to:
NATIONAL MULTIPLEX CORPORATION
3474 Rand Avenue, Box 288
South Plainfield, New Jersey 07080
I-
NATIONAL MULTIPLEX CORPORATION
Z
3474 Rand Avenue, Box 288
m
O.
-I
9
4
7
.-?
2-
.
South Plainfield, New Jersey 07080
SHIP TO:
.................__
............................................................................
....
..
............................................................................................................................................
................................................................................................................................................
More Details? CHECK-OFF Page 102
ZIP...............................................
Data Recorder 8 $149.95
.................. Operating & Technical
Manual (Schematics)
@ $1.00
.............. New Products. No Charge
................
Please enclose $2.00
Shipping & Handling
N. J. Residents add 5%
Sales Tax
january 1976
85
r
AND
"Customized"
i
MIDLAND 13-500
b
12- digit Pad built-in
$299 --Limited Supply!
P
I
WHY
WASTE
WAVS?
-"-I
2 -Meter FM Transceiver 1
KEYBOARDENCODERS
I
Enclosures with lighted pad; pre-wired.
I
Enclosure Only (either style) $8.95
I
:
/
I
I
I
1
KING PRODUCTS SUB-MINIATURE KEYBOARD
ENCODER
COMPLETE WITH NEW MOTOROLA
CHIP AND PC BOARD
--
12-digit assern.
$59.95
16-digit assem.
$69.95
Dealer Inquiries Invited
1
A l l prices PREPAID shipping Cont'I USA
1 KiNG PRODUCTS
' Manufacturer 8 Distributor of Cornrnunicotions Equipment
I
P. 0. BOX A, LOMITA, CA 90717
(213) 534 -4402
l
SWR-1guards against power loss
for $21.95
If you're not pumping out all the
power you're paying for, our little
SWR-1 combination power meter
and SWR bridge will tell you so. You
read forward and reflected power
simultaneously, up to 1000 watts RF
and 1:l to infinity VSWR at 3.5 to 150
MHz.
Got it all tuned up? Keep it that
way with SWR-1. You can leave it
right in your antenna circuit.
@
[email protected]
ELECTRONICS
A s u b s r d ( a r y o f Cubrc Curporalton
305 Airport Road, Oceanside, CA 92054
(714)757-7525
86
january 1976
I
Typocsl component con mclud~ng18 TTL and H C m a chaps as 540 plus pic bond.
Sand $28.50 lor maon plc boad with alignal hor~zontaland vsrtscsl sync orcdlaton
and plans .... or rend $1.00 lrslundablel tor anto pack dsrrnbtng circuot funct~ons.
component Ilne.up. kotr, ple boards. secasoria. arernhlsd Imrdr.
More Details? CHECK-OFF Page 102
I
I
HlGH FRE(IUENCY ANTENNAS
4
ELEMENTS
40
METERS
---' -
=--=Y
\
lk
---.
'\
INTRODUCING THE LONG AWAITED, PRACTICAL SIZED, HlGH PERFORMANCE 4 0 METER
"BIG STICK" DUAL DRIVEN YAGI. NOW YOU CAN HAVE CONSTANT GAIN AND LOW
VSWR ACROSS THE 4 0 METER BAND. DUAL DRIVEN ELEMENTS FOR HlGH EFFICIENCY
AND CLEAN PATTERN. LIGHTWEIGHT BUT STRONG MATERIALS INCLUDING KLM EXCLUSIVE EPOXY INSULATOR DESIGN
...
SPECIFICATIONS
GAIN: 7.25 d B / D I W L E
F/B: 20 d B TYPICAL
FEED IMP:200 OHMS BALANCED
(50 OHMS WITH OPTIONAL
KLM 5-31 4:l BALUN
$13.95)
WEIGHT: 85 LBS.
WIND AREA: 10 SQ. FT.
FREQUENCY: 7.0-7.3 MHz
ELEMENTS: 4. LINEAR LOADED
46' MAX LENGTH
BOOM: 3" DIA. X 42' LONG
TURNING RADIUS: 32'
SHIPPING CONTAINER: WOOD CRATE 12' LONG
125 LBS. TOTAL WEIGHT
-
PRICE $495.00
20 METER 5 ELEMENT
.
15 METER 6 ELEMENT
/
/'
'-. /
---__
KLM 13.9-14.4-5 $249.95
9.7dB GAIN 30dB F I B
KLM 21.0-21.5-6 $224.95
10.5dB GAIN 30dB F I B
WHEN YOU SPEAK OF PERFORMANCE IN
ANTENNAS, AMPLIFIERS OR TRANSCEIVERS THE NAME IS:
17025 LAUREL ROAD
MORGAN HILL, CA. 95037
i
More Details? CHECK-OFF Page 102
january 1976
87
What you
SEE is
ALL
you carry.
...
GLOWoINeTHE
DARKwTT"PADS
plication)
,
TEK-125 1.56"
TEK-165 2.08"
x 2.08~~f57.50
x 2.08"
$65.00
ELECTROGRAFIX
.....................................
.. . . . a 8 6 0 '
10 fo
$8.00
17.00
17.50
17.5
20.00
11.00
1.50
1.95
1.9
2.25
,.-
,,,,wMIc
1.95
1.95
1.95
1.95
R
17.50
17.50
17.50
17.50
'
x 4" a Ir"
-4 leads spaced
.3" x .2"
Each S.65 10 f o r $4.95
-'a"
Built-in batteries (optional)
Sharp 9-digit LED d~splay
Burst or CW frequency
measurements
Sensitivity to 15 mV;
AGC standard
Optional resolution multiplier
provides 0.001 Hz resolution
in 1 sec.
I
1
.
Y
270
'
' '
''
! NOW
Each $
10 f o r 1.40
-
PROGRAMMABLE
ELECTRONIC KEYER 1
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A l l merchandise i s new unused surplus
and i s sold on a money back guarantee.
F i v e d o l l a r mlnimm order. Free f i r s t
class ~ o 4 t a g eon a11 orders. c a l f f o r n i a r e s i d e n i s please add sales tax.
Phone (916) 334-2161
TUX
910-367-3521
SEND FOR
FREE FLYER
*
Sacramento, CA
95043
COMPLETE KIT
ONLY $59.95 ppd.
ASSEMBLED $79.50 ppd.
FEATURES: Dot and Dash Memory. Two
( Independent 2 5 6 Bit Memories, Keys up
I
I
1
I
to -150V. Self Completing Char. 6 to 6 0
WPM, Iambic Keying. Doer not include
paddle.
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1
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NEW ENGLAND
j DIGITAL ELECTRONICS j
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BOX 6 8 4
KENMORE STATION
BOSTON. MA. 0 2 2 1 5
L----------------------------------!
' D o m e s t ~ cU S A Price
John Fluke Mfg. Co.. Ltd.
PO. Box 1094, Station D
Buffalo, N.Y. 14210
Phone (716) 842-0311
january 1976
I
I
14 and 16 p i n 1C packages contafnlng
p r e c i s i o n r e s i s t o r s and capacitors.
NO SCHEMATICS AVAILABLE
Sample indicates most contain 10 t o
15R and 1 o r 2C
"
Assortment of 1: $1.00
ELECTRmICS
I
For data out today, dial our toll-free
number. 800-426-0361.
88
!
.01 CERAMIC DISC
CAPACITORS
15 for $1.00
DIP RC NETWORKS
I\
Fluk~'s
newest
portable count~rs.
P.O. BOX 869
cn 91710
.,,8
h a d ?-input NAND qate:
DIP. P i n c a p a t i b l e w,
SN7400. 4 current d r a i r
Data supplied
'
1
I
II
8 f o r 11.00
plug i n t o
I&! which
a d i p socket
"-'yr 1 -5K and 200K
I
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i
zDiOge
$X\$h\y
MITTER TO:
DIP-12
Trimmer
t u r n trimpots TTL Special 270
@--,,*
I
SEND CHECK or M.O. (cA RES-
Each 1.15
10 pak $1.00
I AMP NEGATIVE
LM320 5V
LM3205.2V
LM320 12V
LM320 15V
!
213565 NPN TO-lOf
30v Beta 150 min.
500 M.
Regulators Tb.3
1 AMP POSITIVE each
I
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1
MEMORIES
825129
1702
1024 b i t ROM(256x4 PROM)
2048 b i t PROM
-2K
-access time 50 NS
-Power d i s s i p a t i o n .5 W/BIT - u l t r a - v i o l e t I i g h l
- T r i - s t a t e output
erasable
-static units
- F i e l d progranmable
-16 p i n DIP
Each $9.95
Each 15.00
8 for $34.95
LM309K 5V
6V
7806
7R12
12V
785
1
7824
24V
]
(714) 627-4287 (714) 627-1753
MONEY BACK GUARANTEE
FROM STOCK
I
:
I
--
TEK SERIES
(All .40" THICK)
CLUB DISCOUNT
ON 1 0 OR MORE
520 MHz
'
j
j
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GUARANTEED RF PROOF WILL
MODULATE ANY TRANSMITTER
LED TONE
BATTERY
INDICATOR
AOJ. LEVEL CONTROL, 6-16 VOC
@ 15 mA max.
XTAL CONTROLLED DIGITAL CMOS
SINGLE UNIT ABS CASE FALSE TONE PROOF
SCHEMATICS FOR 3 WIRE
HOOKUP ON REPUEST
SPECIFY POS OR NEG GROUND
(Quantity & OEM prlces on ap-
More Details?CHECK-OFF Page 102
I
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YOUR SUPERMARKET
OF AMATEUR VALUES
YOU MADE US THE NATION'S FM LEADER . . .
NOW LET US HELP FILL ALL YOUR AMATEUR NEEDS
I
I
I
PERSONAL, FRIENDLY SERVICE
I
LOTS OF
j MOTOROLA GOODIES j
TOO!!
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1
PROMPT MAIL & PHONE SERVICE
a LIBERAL TRADE INS
QUALITY BRANDS
I
MOTOROLA FANS . . . NEW,
t
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SPECIAL GOODIES LIST FREE FOR S.A.S.E.
I
SEE YOU AT SAROC
SPECTRONICS, INC.
1009 GARFIELD
OAK PARK, IL. 60304
3 12-848-6778
TELEX 72:8310
More Details?CHECK-OFF Page 102
HOURS
STORE HOURS:
Yon-lhun 9:306%lo, Fri. 9:3k t 9:30.3:00, C l o s d Sun. k Holidays.
am
january 1976
89
THIS IS YOUR BIG CHANCE!
BUY $50 WORTH; THEN PICK $50 WORTH FREE!
OTHER ORDERS: $ l o + Orders take 5% Discount; $30+ Orders take 10% Discount
D M 8000
8230N 2.50
8830N
7473
.40
74141 1.10 74177 .85
7 4 0 0 SERIES
8090N .60 8288N 1.10 8831N
74145 1.10 74180 .95
.45
7400 .17
7437 .45 7474
8092N .50 8470N .50 8832N
74151 1.25 74185 2.25
.75
7401 .I7
7438 .40 7475
8095N .50 8520N 1.20
8833N
74153 1.45 74189 3.00
.40
7402 .17
7439 [email protected] 7476
8835N
8097N .50 8598N 4.90
74155 1.25 74190 1.50
7403 .17
7440 .20 7483 1.10
8836N
8123N 1.55 8599N 3.00
.90
74157 1.40 74191 1.50
7406 .45
7441 1.00 7492
8R37N
8130N 2.10 8612N 2.00
74161 1.60 74192 1.25
.90
7410 .20
7442 1.00 7493
8210N 3.10 8613N .75
a853N
74162 1.45 74193 1.25
.90
7413 .75
7443 1.00 7496
8211N 1.95 8640N .50 8864N
74163 2.40 74195 1.00
7416 .45
7445 .95 74100 1.50
8RRON
8212N 2.50 8796N 2.00
74164 2.40 74196 1.25
7417 .45
7446 1.15 74107 .45
8214N 1.75 8810N .50 8895N
74170 2.90 74198 2.20
7420 .20
7448 1.15. 74122 .50
74173 1.70 74200 7.00
8220N 1.50 8811N .85
7425 .35
7450 .25 74123 1.00
9582N
7426 .30
7454 .35 74126 .75
8223N 3.00 8812N .50
74174 1.85 57430 .25
7460 .25 74132 2.85
74175 1.85
8225N 2.50 8R22N 2.60
7432 .25
7472 .40
-
.30
2.55
2.55
1.15
1.00
.50
1.45
.95
1.95
1.35
1.00
:::
1. Add 5 0 t for postage & handling on orders under $10.
3. Send SASE for Bargain Flyer.
2. All items guaranteed.
4. SEND YOUR ORDER ALONG WITH CHECK OR MONEY ORDER TO: WEIRNU,
P. 0. Box 942, Colton, CA 92324 (Calif. residents include 6% tax).
WEIRNU
PO Box 942, Colton,CA w324
SSB ...CW ...FM ...80-10.. .VHF ...UHF
5
.
~~
.*w;*
a
c
u
d
c
lm
mmm
PERSONALIZED SERVICE FOR ALL YOUR AMATEUR NEEDS
New Equipment
Transmitters
Receivers
Keyers
E!
rm
THE MOST IMPORTANT
FEATURE OF
YOUR ANTENNA
I S PUlTING
I T UP WHERE
ONLY
I
Engraved Front
Drilled P.C. Board
All N~csSiIryCompOnentS
Detailed Instructions with Simulations
HOSFELT ELECTRONICS
224 OPAL BOULEVARD
STEUBENVILLE, OHIO 43952
PHONE 614 264-6464
NEW YEAR SPECIAL
All towers mounted
Wrlte for 1 2 page brochure gtvtng dozens of comblnatlons of he~ght,wetght
and wlnd load
ALSO TOWERS FOR WINDMILLS
MANUFACTURING CO.
In Almont He~ghtslndustr~alPark
ARD-TO-FIND PRECISION TOOLS
$24.95
Easy to Assemble
And now, wlth motorized options, you
can crank tt up or down, or fold tt
over, from the operattng posttlon In
the house.
&Ei
Prepaid
Phenolic Case
Complete Telescop~ng
and Fold-Over
Series available
-
1 0 0 9 G A R F I E L D STREET
O A K P A R K . ILL. 6 0 3 0 4
(312) 848-6778
COMPLETE KITS
-
ALUMINUM
FM Transceivers
Preamps
Mobile Antennas
Beams
SPECTRONICS INC.
test your skills on the
"WHEEL OF FORTUNE"
I T CAN DO
WHAT YOU EXPECT.
RELIABLE DX
SIGNALS EARLIEST I N
AND LAST OUT.
Used Equipment
Publications
OSCAR Antennas
Coax
...
THE BRIMSTONE 144
Space buys more and pays more.
Highest prices ever on U.S. Military
surplus, especially on Collins equipment or parts. We pay freight. Call
collect now for our high offer. 201
440-8787.
NEW ADDRESS
SPACE ELECTRONICS CO.
div. of Military Electronics Corp.
AUTOMATIC ELEC.
PAD & ENCLOSURE
STRETCH THOSE DOLLARS!
We'll team up a brand new Brimstone
144 with Touch.Tone0 Interface and Automatic Electric Pad & Enclosure, wired
and ready to go . .. all for only $710.00
Nye Viking and Ten-Tec equipment available.
Call or write for immediate assistance.
COMMUNICATION SPECIALTIES INC.
9 7 AMSTERDAM AVENUE
BOX 4 7 1
WARWICK, R. 1. 02889
*T.M. of A. T. & T.
401-738-3287
P. 0.
MILITARY SURPLUS
WANTED
35 Ruta Court
S. Hackensack, N.J. 07606
NEW YEAR SPECIAL!
Complimentary issue of
THE BIG LIST from
Buyers d. Sellers. Check off #329.
r4h'€ffi €3 S L L k f f i
P.O. BOX 7 3
Kenmore Station
Boston. Mass. 02215
en-636-8777
More Details? CHECK-OFF Page 102
-
flea
market
RATES Non-commercial ads 106
per word; commercial ads 406 per word
both payable in advance. No cash discounts or agency commissions allowed.
HAMFESTS Sponsored by nonprofit organizations receive one free Flea
Market ad (subject to our editing). Repeat insertions of hamfest ads pay the
non-commercial rate.
COPY No special layout or arrangements available. Material should
be typewritten or clearly printed and
must include full name and address. We
reserve the right to reject unsuitable
copy. Ham Radio can not check each
advertiser and thus cannot be held responsible for claims made. Liability for
correctness of material limited to corrected ad in next available issue.
DEADLINE 15th of second preceding month.
SEND MATERIAL TO: Flea Market,
Ham Radio, Greenville, N. H. 03048.
THE LARGEST SWAP AND
- SHOP
-~ I
..N. MICHIGAN.
....
southfield ~ m a t e u rRadio Clubs. January 18.
1975, Southfield High School, Ten M ~ l eand
Lahser Rds., Southfield, MI. Tickets $1.50. For
more information regarding tickets and/or
tables, write to Mr. Robert Younkers, 24675
Lahser Road, Southfield, Michigan 48075.
SELL THE FOLLOWING: Hallicrafters FPM3OO
Telerex 6 el beam. Winford Barnes. Box 28.
Bunker Hill, In. 46914.
-
WISCONSIN
West Allis Radio Amateur
Club annual Midwinter Swaofest. Saturdav.
January 24, 1976, 8 a.m. a t t h e ~ a u k e s h s
County Expo Center. Directions: 1-94 t o Waukesha Co. F, south t o FT, west to Expo Center.
Talk.in 146.52 MHz. Tickets $ 1.50 advanced.
$2.00 a t door. (Dealers: advanced registration
only.) Write: WARAC, P. 0. Box 1072, Milwaukee. WI 53201.
TRADE
Single channel VHF receiver 108152 MHz Ex-FAA crystal control squelch
double conversion, w a n t R390 o r R389 o r R648.
B o b Bose. 6821 Sally Lane. Edina. M N 55435.
C,OMPUTER HOBBYISTS! Bargain h u n t o r sell
vla On-Line. 18 issues/year - $3.75. Free
sample issue from: On-Line. 24695 Santa Cruz
Hwy., Los Gatos, CA 95030.
WANTED: Couole "ICEMAN" 2 meter FM transceivers, advise condition, price. Ed Aymond,
W5UHV. 6730 Westlake, Dallas, TX 75214.
"HAM BUY LINES" Send name and address
f o r Literature. Vito lacopelli. 1720 77 St.,
Brooklvn.
- . New York 11214.
SPECIAL DESIGNED P.C. BOARDS: Will quote
a n d build special boards p e r customers specifications. For complete information contact
Wayne Camp, Camp Control Co., P. 0. Box
174. Garland, Texas 75040.
DO-IT-URSELF DXPEDlTlON
Stay a t Z F l S B
- Cayman Is. V e r t ~ c a lantenna and C a r ~ b b e a n
a t your doorstep. Diving/fishing if band folds.
Write Spanish Bay Reef Resort, Box 800K,
Grand Cayman, B. W. I.
DX-60, HG-10, $50 plus shipping. SASE f o r
other items. WB6PCV, Marty Bigos, 1926
Fell, S. F., Ca. 415-387-0409.
FERRITE BEADS: Ferroxcube beads w/specifi.
cation and a p p l i c a t ~ o n sheet - 10 O $1.00
postpaid. Includes latest catalog. CJO Surplus,
Box 189, Braintree, Mass. 02184.
TELEVISION diagnostic repair course prepared
by master technicians. Lessons only $6.00
each. Optional m a t c h ~ n g one hour cassette
tape $6.00 each. Send f o r first lesson and
master index. Guardian, 20 E. Main, Ramsey.
N. J. 07446.
COLLINS; 30s-1 i n excellent operating and
physical condx f o r Bendix R-1051B/E receiver.
Sid Sidman. 3571 Gresham Court. Pleasanton.
Calif. 94566.
,-
CUYAHOGA FALLS Amateur Radio Club Annual Auction and Flea Market. Date: February
27, 1976. Place: Bolich Jr. High
Cuyahoga
Falls, Oh. Admission: $1.50 advanced registration. Deadline Feb. 1. 1976. $2.00 door night
of auction. Talk-in frequency: 84/24-04/64.
52/52. Call WBVPV. Advance Tickets: K8VAK
& XYL. 3043 De Walt Dr., Akron, Oh 44312.
216-644-1213.
-
-
ORIGINAL PETIT MORSE TO R l T Y CONVERTER
Inventory Closeout. Manufacturer discontinued
production. Fantastic price reductions semi-kit $95, parts k i t $255. assembled and
tested $380. Also Baudot t o Morse (with 64
character buffer) $135 and Baudot t o ASCII
(perfect f o r TV typewriter!) $59. SASE f o r de.
tails. Walters, Box 563. Oak Harbor, Wa. 98277.
-
-
ENGRAVED RADIO LICENSE. Exact reproduc.
tion i n solid brass. Permanent i d e n t i f ~ c a t ~ o n .
Send good, Xerox copy, with $5.00, t o Metal
A r t Graph~cs. 1136 Potomac Ave., Hagerstown. Md. 21740.
FIGHT TVI with t h e RSO Low Pass. Filter. For
brochure wrlte: Taylor C o m r n u n ~ c a t ~ o nManu.
s
facturing Company, Box 126, Agincourt, On.
tario, Canada. MIS 384.
-
MICRO-TO M K II deluxe epoxy-glass drilled
circuit boards. $4.00 postpaid; with semicons
$11.80. K3CUW. 13048 Mass. Ave. S.E., Wash.
ington. D. C. 20003.
PORTA-PAK t h e accessory that makes your
mobile really portable. $59.95 and $39.95.
Dealer inquiries invited. P. 0 . Box 67, Somers.
Wisc. 53171.
WANTED: tubes, transistors, equipment, what
have you? Bernard Goldstein. WZMNP. Box
257. Canal Station. New York. N. Y. 10013.
-
-
-
-
WYOMING RANCH LAND. Wild horses, ante.
lope, deer. elk. 10 acres $30 down, $30 month.
FREE Maps - Photos -Info. Owner - K61CS.
Mike Gauthier. 9550 Gallatin. Downey, CA.
90240.
-
-
JAPANESE TRANSISTORS
All Transistors
original factory made. Over 500 types available. Write for free catalog. West Pacific Electronics. P. 0. Box 25837. W. Los Angeles,
CA 90025.
KIT - Send
TRAVEL-PAK QSL
call and 25+;
receive your call sample kit i n return. Sarnco,
Box 203, Wynantskill. N. Y. 12198.
VERY in.ter-e2t-ing! Next 4 b i g issues $1. "The
H a m Trader. Svcamore. I L 60178.
-
MODERN 6 0 MIN. CODE CASSETTES. Novice
0-5 wpm. Progressive 5-13 wpm. General 13-15
wpm, Extra 20-22 wpm. $3 each. 4/$10. Royal.
Box 2174. S a n d u s k ~ .Ohio 44870.
-
QRP TRANSMATCH for HW7, Ten-Tec, and
others. Send stamp f o r detatls to Peter Meacham Associates. 19 Loretta Road. Waltham.
Mass. 02154.
RECONDITIONED TEST EQUIPMENT f o r sale.
Catalog J.50. Walter. 2697 Nickel. San Pablo.
Ca. 94806.
OSL'S
BROWNIE W3CJI
30358 Lehigh,
Allentown, Pa. 18103. Samples with c u t catalog 35e.
..
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ROCHESTER HAMFEST 1976 ,is Saturday,. May
22. Your name added t o m a ~ l ~ nl ~
g s to r Infor.
mation
write: Rochester Hamfest, Box
1388, Rochester, N. Y. 14603.
-
FREE Catalog. LEDS, microphones, nicads, IC's.
relays, ultrasonic devices, precision t r i m m e r
capacitors, digital thermometers, unique components. Chaney's, Box 15431, Lakewood.
Colo. 80215.
BAZOOKA. DIPOLE
Ready t o use with
fiberglass center ~ 0 2 3 9 : end insulator' 80M.
$29.50. 40M. $26.50. 20-15-IOM, $23.50 Fiberglass central insulator with S0239, 1000
pound test, $5.95. Trap 2 KW 80/40. 40/20.
$18.50 ppd. 1000 pound test. JAC-TENNA.
13850 Victorin. Tracy. P. Que. Canada.
-
CANADIAN JUMBO SURPLUS and Parts Cata.
logs. Bargains Galore. Send $1. ETCO-HR, Box
741, Montreal "A" H3c 2V2.
OSCAR SLIDES, set o f 5. $1.25. Launch and
spacecraft. Proceeds AMSAT. K6PGX. P. O.
Box 463. Pasadena, CA 91102.
-
-
TELETYPE EQUIPMENT FOR SALE f o r begin.
ners and experienced operators. RTTY machines, parts, supplies. Special beginners
package consists o f Model 15 page printer
and TH5-TG demodulator, $125.00. Atlantlc
Surplus Sales. 3730 Nautilus Ave., Brooklyn,
N. Y. 11224. Tel: (212) 372-0349.
HOMEBREWERS: Stamp brings list o f high
quality components. CPO Surplus, Box 189,
Braintree, Mass. 02184.
STOLEN f r o m Findlay Radio Club, Inc.. club
house in Findlay. Ohio. on Oct. 13 o r Oct. 14
(it was o n t h e nite o r morn., 13 o r 14 respectively 1975. 1 - TR-4. Serial No. 16457-A.
Drake transceiver; 1 - AC-4. Serial No. 30557.
Drake power supply; 1 - 250C. Serial NO:
E189109. Swan SSB transceiver: 1 - 117XC.
Serial No. 015095, Swan power supply; 1 Astatic D-104 microphone with UGB stand; 1
FM.2X, Serial No. 11454, Swan transceiver
with M-1002 microphone; 1 - FM-2X, Serial
No. 11454, Swan matching supplv; 1 - TV-2,
Swan 6M to 2M transverter. F ~ n d l a y Radio
Club, Inc., P. 0. Box 587, Findlay, Ohio 45840.
-
-
SOCIETY OF WIRELESS PIONEERS offers Life
Membershir, t o active and former C.W. operators on cdmm'l.. military. gov't.. etc. wireless/
radio circuits. Contact: Society of Wireless
Pioneers. Dept. H. P. 0. Box 530. Santa Rosa.
California 95402.
-
PC's, Send large S.A.S.E. f o r list. Semtronics.
Rt. #3. Box 1. Bellaire. Ohio 43906.
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MOBILE IGNITION SHIELDING provides more
range with no noise. Available most engines
i n assembled o r k i t forms. plus many other
cuppresston accessories. Free literature. Estes
Engineering. 930 Marine Dr.. Port Angeles.
WA. 98362.
-
WANTED: R.390A parts. W6ME. 4178 Chasin
Street. Oceanside. Ca. 92054.
NEW CANADIAN MAGAZINE. "Electronics Work
Shop". $5.00 yearly, sample $1.00. ETCOG.
Box 741. Montreal. H3C 2V2.
TELL YOUR FRIENDS about Hasm Radio M a g
azine.
-
-
QSL CARDS
Something completely different.
Nothing even close t o it on the market! Sam.
ples: 25C. W5UTT, Box 1171D, Garland, TX
75040.
SELL: Drake ML-2, 2 M FM. Absolute m i n t
condx! Xtals for 9 channels. Complete - $219.
WA3CUQ, 337 E. Main St., Kutztown, Pa. 19530.
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Miami. Florida
TROPICAL HAMBOREE
January 24-25. The really international hamfest
in a genuinely international city. Meet your
island and Latin American DX friends i n the
only p a r t of t h e USA - including most of
Florida - with a 99 percent promise of Jan.
uary tropical sunshine. Hamboree traditlonal
goodies plus - it's traditlonal! - always
something new. The latest f r o m t h e manufacturers - the not so late in the giant in.
door flea market! At the ARRL forum. January
Board Meeting results. Bicentennial QSO/QSL
contest, sponsored by City of Miami, announcement and kick.off by M i a m i officials.
Keep u p with the state of the art at "Skip"
Tenney's renowned microprocessor seminar
(details f r o m Skip at H a m Radio Magazine).
For the lucky, an Atlas 210X. Heath HW104.
Heath 2026, and an ICOM 230 plus m u c h
more. The YL's list includes a beautiful diamond ring! Registration $2.00. Hotel data on
request. Oade Radio Club, P. 0 . Box 520073.
Miami. FL 33152.
-
TELETYPEWRITER PARTS. gears, manuals, supplies, tape. toroids. SASE Ilst. T y ~ e t r o n l c s .
Box 8873. Ft. Lauderdale. FI. 33310. Buy parts.
late machines.
MANSFIELD. OHIO MID-WINTER HAMFEST/
AUCTION
new day and location. Sunday.
February 1. 1976. at Richland County F a ~ r grounds. Forums, indoor flea market, displays,
door prizes, and auction; easy access f r o m 171
and U.S. 30. Registration $1.50 i n advance.
$2.00 a t the door. Tables f o r flea market $1.00
each. Doors open at 9 a.m.. auction a t ?:00.
N o commission charged. Talk in 3.972.5 kHz.
146.52 and 146.34/94 MHz. Additional info
f r o m KBJPF. Harry Frietchen Jr.. 120 Homewood Rd., Mansfield. OH 44906. (419) 5292801 home; (419) 524.1441 work.
-
STOLEN Regency HR-212 transceiver with
microphone and mobile bracket, serial 2400521: a Vanguard Labs model 201 pre-amp.
attached to the back of the HR-212, and a
Collins radio logbook. Stolen f r o m m y c a r at
Aurora College. Aurora. Ill.. on Nov. 13. Randy
Thompson, 842 Shagbark Lane. Apt. 302,
North Aurora, I L 60542.
CT.101
it130153. w l m o d s
and
Sh'ure
444.
NEW
NEW
NEW
Transistor and Relay A 5
sembly
consists of (2
MJE3055 and (2) MJE2954
transistors (10 amp, 90w.
60v complementary pairs)
mounted i n "U" channel
hea!, sink 2%*' x 1lh" x
1'/,
(2) XTAL CAN RELAYS. OPDT, 28v. 8000!!.
5.8 ma DC. 1 amp contacts
mounted on PC board with
resistors.
$2.85 ea. ppd.
-
.
1
-
WHY
WE CUBE
USE LESS THAN THE BEST?
The Quality designed and built Into
this M-Tech Amplifier allows us t o
include our famous ONE YEAR WARRANTY
-
UNPOlTED TOROIDS
All
tomids are center tapped,
88MHY
Price is a low 5 for $2.75 ppd.
11h inch miniature aIIigator clips. Bright vinyl
red or black insulator.
Nickle plated. 9 for $1.00
-
NEW SIZES
VERTICAL MOUNT PC
BOARD POTENTIOMETERS
~ m e r l c a nmade (CRL) high quali t y pots. Available i n the followi n g sizes: 750 ohms. 1500 ohms.
25.000 ohms. 50.000 ohms,
100,000 ohms.
Price i s 5 for $1.10 ppd.
--
-
Transformer
American Made
Fully
24-0-24
shielded. 115 V Primary. Sec.
8 1amp with tap at 6.3 volt for pilot light.
Price
A low $3.15 each ppd.
CRL DISC CAPACITORS
.1 MFD, 1OV K " dia., long leads.
10 for $1.00 ppd.
SUB-AUDIBLE GENERATOR
for FM
Inexpensive m u l t i tone
system
Compatible with P L CG QC
Low distortion sinewave
A d j u s t a b l e frequency
( 9 8 - 2 5 0 Hz). L o w e r
available
Rugged, p l a s t i c encased with leads, easy
t o mount
Input 6-18 VDC unregulated
Excellent stability
-
. S X A Xh~
Lyle Pmducts
P.O.BOX 2083
S.nt. C l m C.ll
95051
Price $19.95
MODEL P50AI
Mode: Class C for CW and FM
DC Input: +13.6 V DC @ 8 amps for
rated output
RF Input: 1-3 watts 140-165 MHz
RF Output: 40-60 watts 140-165 MHz
Load Sensitivity: internally protected
for any VSWR
Connectors: low loss 50R BNC
COR switching w/LED indicator
Spurious output filter
Unique Low frequency negative feedback circuit
Send SASE for info add'l models
ppd. c;t&nental
$139.00
g
Calif. res. add 6%
Freq. set at factory $5.00 extra
Send for more information
-
ORDER TODAY FROM:
&Tech Engineering, Inc.
BOX C, SPRINGFIELD, V A 2 2 1 5 1
(703) 354-0573
Wlsoecs.
$3.'50 each, 3 for $10.00
M-TECH
-
. . . The Quality Company
New I T E M S .
FREE
. . New
BARGAINS!
U P O N REQUEST!
If you haven't rece~vedour new Catalog, w r ~ t efor free copy today. Address: Dept. HR
Transformer
IDEAL FOR 2M POWER
115 VAC primary, 18 volt. 5 amp ccs or
7 amp intermtttent duty secondary.
$6.60 ea. ppd.
-
MINIATURE SNAP ACTION SWITCHES
SPDT lea! actuator, 10A. 125v AC. 1Ih" x
601%ea. or 3 for $1.55
,, x 3 h
&ST
N.O. Cherry "Button Typev: E34.
15A, 125v AC. 1 A " x %" x %I
50e ea. or 3 for $ 1.35
SPST N.C. Acro "Button T pe~; (tab accessable t o make SPOT)
x )/." x
3h
50r. eb. or 3 for $1.35
fib
c
=
a
BACK I N STOCK ONCE AGAIN!
3000 MFD
@ 30 Volt
Capacitors.
Slze 1" Diameter x 3" Long. 90e Each
or 3 For $2.25 ppd.
-
SPST SLIDE SWITCHES (Red) Made b
4A, 125" A.C. 25e ea. Ppd:
Stackpole
-
3 inch 4 ohm VC Square
frame speaker 0.3 watt with
4 mounting holes.
$1.35 each ppd.
-
PIONEER
2%" dia. Round Speaker,
7/8 deep. 16% 0.3 watt. $1.45 ea. ppd.
OVAL SPEAKER. 2" x 4" x 11h" deep. 89.
0.3 watt, anodized with 4 mtg. holes.
$1.65 ea. ppd.
AMERICAN MADE
leads.
%'I
DUAL Electrolytic 1000
& 5 9 MFD. 15V, long
dia. x 2%
long.
55c each 3/$1.50 ppd.
14 Wire. color coded #22 ribbon wire.
i0c/ft. or 101/$1.25
OW
- limited
-
SEND STAMP FOR BARGIN LIST
Pa. residents add 6% State sales tax
ALL ITEMS PPD. USA
Canadian orders for less than $5.00 add
$1.00 t o cover additional mailing costs.
2 METER
CRYSTALS
IN STOCK
FOR THESE RADIOS ON
STANDARD ARRL REPEATER
FREQUENCIES:
-
DRAKE
TR-22
GENAVE
ICOM/VHF ENGINEERING
KEN/WILSON
REGENCY HR-2A/HR-212
HEATHKIT HW-202
REGENCY HR-2B
S.B.E.
STANDARD 1 4 6 / 8 2 6
STANDARD HORIZON
DUPLEXER KITS
PROVEN DESIGN. HUNDREDS SOLD IN US,
CANADA, EUROPE. CONSTRUCTION WELDED
ALUMINUM IRlDlTE & SILVER PLATED. SEE
JAN. 74 QST RECENT EQUIPMENT. ALL PARTS
PROFESSIONAL QUALITY. EVERYTHING SUPPLIED. NO SPECIAL TOOLS. RECEIVER &
TRANSMITTER CAN BE USED FOR TUNE UP.
MOD. 62-1 6 CAVITY 135-165 MHz POWER
250W ISOLATION GREATER THAN 100
dB 600 kHz. INSERTION LOSS .9 dB
MIN. TEMP STABLE OVER WIDE
RANGE
PRICE $349.00
MOD. 42-1 4 CAVITY SAME AS 6 CAVITY
EXCEPT ISOLATiON GREATER THAN
80 dB 600 kHz INSERTION LOSS .6
PRICE $249.00
dB MAX.
NORTH SHORE RF TECHNOLOGY
Exclusive Distributar TUFTS Radio
386 MAIN ST., MEDFORD, MA 02155
617-395-8280
Send for free frequency
list and order blank to:
KENSCO
COMMUNICATIONS INC.
DEPT. 1 0 1
BOX 469, QUINCY, MA. 02169
PHONE: (617) 471-6427
Iwlated - Pad . Drill - Mill
SIZ~S
20.15.1O#n,d~a
. - $7 .86r...
0ST.M.w. 73.p.l4.Or. 73.p.14
Hnnls & Kinks. 0-82
A F STAHLER Co
4
92
,
v.
electronic speciallies-BOX 353, IRWIN, PA 15642
january 1976
More Details? CHECK-OFF Page 102
BRAND NEW CARTRWlSlON COLOR VIDEO
RECORDER-REPRODUCER ELECTRONIC UNIT.
Contalns power supply with adjustable, regu.
lated outputs of + 10 t o t 18 VDC.
(rfr 15 VDC
1 % amps) Third output is 10
VDC at 3 amps. Perfect for CMOS. TTL. Op.
Amps and MICROPROCESSORS. Contains over
900 parts with extremely long leads. Includes
182 transistors, IC's, diodes, and FET's, numerous resistors. capacitors, crystals, inductors.
varicaps and delay lines. (One, 63.5 microsecond, precision, quartz. acoustically coupled
delay line which stores one line of TV.) Transistors will operate i n HEATHKIT N ' s . Schematics and semlconductor cross reference
$ 1.50 shjpsupplied upon request. $19.95
ping. 500 for brochure. Mad~son Electronics
Company. Inc., P. 0. Box 369, Madison, Alabama 35758. Money back guarantee.
THE BEST WAY
TO MONITOR RADIO CHANNELS WITHOUT LISTENING
TOUCH-TONE
DECODER
$75.00
+
DESOLDERING AIDS AND HAND TOOLS. R.
L. Syphers Associates. Box 883. Dept. H.
Bensenville. Illinois 60106.
MAYNARD ELECTRONICS recently purchased the entire stock of discontinued
models of PLL TOUCH-TONE DECODERS from a major commercial manufacturer.
Our agreement stipulates that the sale of these units will be limited to the amateur radio market. Because the sale price is below the manufacturer's cost, i t is
necessary t o limit sales to five units per ham to prevent commercial speculation.
-
TELETYPES: Model 19,, $175. Model 15. $75.
516.581.6509. Al Shaplro.
EXCLUSIVELY HAM TELETYPE 21st year.
RTTY Journal, articles, news. DX. VHF. classified ads. Sample 356. $3.50 per year. Box
837. Royal Oak. Michigan 48068.
FEATURES:
Virtually immune t o f a k i n g by voice. CTCSS tones, music and noise.
Includes a CALL LIGHT and BUZZER
Output f o r vehicle HORN connection
Relay UNMUTES SPEAKER when call is received
Field programmable for UP TO EIGHT DIGIT code sequence
May be used for MOBILE o r FIXED
Designed for 12 VOLTS DC Pos. or Neg. operation
Dimensions: lI/. x 4 % x 5 15/16 inches
Units are brand new. Complete satisfaction i s guaranteed. I f for any reason ou are not completely satisfied, just return the undamaged unit within ten days for r e f u n x
-
MICHIGAN CHERRYLAND AMAT€UR RADIO
CLUB annual Swap N Shop. Saturday. 14
February 1976. 9:00 a.m. t o 4:00 p.m. at the
Northwestern Michigan College camDus i n
Traverse City. Talk-in will be 146.52 and
1935. Door prizes. Donation is $1.00. For information contact Bill Mader. WABWWM. Box
2. Empire A.F.S.. Mi. 49630.
FOR SALE: SB-100 with HP23A. $275: SB220.
$350. lBAVT/WB, $40: DX-BOB with VF-1
VFO.' 540: HR-106. $40. Wanted used tower.
tri.band beam ham-m rotator. John Merrill.
W A I U V . 8 sp;uce Drive. Dover. N. ti. 03820.
MODEL 20006 TOUCH-TONE DECODER AND MANUA
$75.00
MATING CABLE. MULTI-CONDUCTOR CABLE WITH MOLEX CONNECTOR ................................ $10.00
Please emlase check or money order for the total amount plus 55.00 for shipping and handling. A $10.00 deposit
i s required on C.O.O. shipments. F.O.8. Belmont.
Include your name, shipping address, ZIP code and ham call sign. Calif. residents add sales tax.
-
ANTENNAS: Dipole, multiple band arrays. 15
thru 75 meters from $59.50. Mobile Antennas
20M. 40M. and 2M from $19.50. Baluns:
1:l and 4 : l
$12.95 ea. Data Available. Savoy
Electronics. Inc.. P. 0. Box 5727. Ft. Lauder.
dale, Fla. 33310.
- CB.
* 6 6 e3.1
.
HURRY1 ONLY 50 UNITS REMAINING!
LOWEST PRICE EVER OFFERED
FOR A QUALITY TOUCH-TONE DECODER
-
MAYNARD
ELECTRONICS
COMPANY
P. 0. Box 363, Dept. A
Belmont, Ca. 94002
-
TELETYPE MODEL ,28: 28R0 bases. $35.00,
3/$100.00. New Rlbbons. $1.50. Typeboxes
(WX. COMM, or Fractions) $25.00 ea. ASR
base for LXD TD. $25.00. Base - U D standalone. 530.00. M28 cabinets. Rears. gearshifts.
reperf's. TD's keyboards, t e h i n a l units, paper, tape. A ~ R ' S , KSR's. SASE for complete
list. L. PfleEer. 532 W. Wllson St.. 3 1 .
Madison, WI 53703.
Phone (415) 592-1553
Touch-Tone is a reg. T.M. of ATLT Co.
V H F/UHF
CONVERTERS
PREAMPS
Ten meters through 432 MHz. A post card
will bring our full 1976 Catalog.
260 N W POLK AVE.
CORVALLIS OREGON 97330
~ e l e o h o n e503-757.1134
~
-
-
WHEATON HAMFEST
The Wheaton Community Radio Amateurs mid-winter hamfest is
Sunday. February 8. at the DuPage County
Fairgrounds. Wheaton. Illinois (Manchester
Road near County Farm Road). 8 a.m. to 5
p.m. ' ~ i c k e t s$1,.50 advance. $2.00 at the door.
For advance tlckets send $1.50 each and a
self-addressed stamped, envelope t o L. 0.
Shaw. W90KI. 433 S. V1lI.a Avenue, Villa Park.
lllinois 60181. Advance tlckets postmarked no
later than February 1.
FOR SALE: FPM300 m i n t condition. Ceramic
mike S500 or best offer. Call 617-468-3926.
-
-
SELL
TRADE. Write for free mailer.
BUY
Give name. address, call letters. Complete
stock o f major brands. New and reconditioned
equipment. Call us for best deals. We buy
Collins. Drake, Swan, etc. SSB & FM. Assoclated Radio. 8012 Conser. Overland Park.
Ks. 66204. 913-381.5901.
-
-
INDIANA
THE FIRST HAMFEST OF 1976.
the Fort Wayne Hamfest. Is January 18. 1976.
at Shiloh Hall, one.half mile west of Indiana
3 on the Carroll Road. More tables and space
than last vear. Flea market, food, drinks.
Tickets are $1.50 at the door. XYL's and children under 12 free. Tablez avallabla at $1.00
for 4 feet. Talk.in on 28-8 and 16-76. Every
one welcome t o start off 1976 with a ban I
Write to the AC-ARTS, Inc.. q. 0. Box 34%
Fort Wayne. IN 46801 for detalls.
gills
More Details? CHECK-OFF Page
Dl.lStlC
body
I0
aCCCB1
Iceal~nc D r ~ p
Inslrbc.
1,ons locludsd Cuaralltrcd At you.
acalc-r
or $3.95
portpaid. Corn.
PL 2 5 I plug on
cap keep% con* f~tllng, dry
rod.
Don't lose your favorite frequency
panoon ~ n s u l a l o ? %
20.99.
T h e F C C has said "either-or" o n
licensing, b u t t o pass Advanced a n d
E x t r a Class exams, y o u need the
technical guidance as offered b y N R I .
N R I Advanced A m a t e u r Radio i s f o r
t h e h a m w h o already has a General,
C o n d i t i o n a l o r Tech Class ticket.
Basic A m a t e u r Radio i s f o r t h e beginner and includes transmitter.
3-band receiver, code practice equipment. T h r e e t r a i n i n g plans offered.
Get a l l t h e facts. M a i l coupon. N o
obligation. N o salesman w i l l c a l l o n
you. N A T I O N A L R A D I O
I N S T I T U T E . Washington,
D.C. 20016.
BUDWIG MFG. CO. PO ~ 0 . 9 1 Ramona.
~ .
CA 92065
I
i Your BEST BUY in KITS
i Freq. Counter Kit - 0-300MHz$99.00
Freq. Counter Kit - 0-500 MHz
$139.00
\ Basic Clock Kit - full 6 digit $17.95
I
I
I Electronic Dice Game Kit ...... $10.95
I Function Generator Kit ......... $10.95
I Op-Amp Designer's U n i t coming
I soon!
I Also DVM available shortly.
1 Various other kits and electronic
I components available. Send SASE
I for flver.
I
I
WANTED: Cablnet for 515-4 Collins. KP4BJM.
1713 Gardenia St.. San Fco.. Rio Piedras.
P. R. 00927.
IlllCO
NRI, leader I n Communications,
Television, Electronrcs a n d T V Radio home t r a i n i n x , n o w offers t h e
f i r s t i n A m a t e u r Radio courses, designed t o p r e p a r e y o u f o r the F C C
A m a t e u r License y o u w a n t o r need.
I
I
I
....-
@
............. MAIL NOW .............
:
:
:.
NATIONAL RADIO INSTITUTE
46-016
Wash~ngton.D C 20016
Please send me bnforrnation on Amateur Radlo
lraonlng
Name
:
Mep
Address
BOX
P. 0.
1101
SOUTHGATE, MICH. 48195
(313) 285-1782
I
I
I
!
:
.:
:
.......................................
City
ACCREDITED MEMOIR NITIONL
StateZlpn o w STUDY COU~CIL
january 1976
93
WANTED WANTED
YOUR CLEAN DRAKE TRADE-INS
WILL ALLOW I N TRADE FOR YOUR DRAKE . . .
OPEN EVERY NIGHT UNTIL 9:00 P.M.!
Our way of giving you the very best in service is
longer hours and more equipment.
Drake is the newest line to be signed on board.
Whether you're a Novice or an Extra Class a visit to
our store should be a must on your list.
TR-3/AC-3/MS-3
$350.00
T R 4 / A C 4 / M S 4 BELOW S/N 31320 .................. $400.00
T R 4 / A C 4 / M S 4 ABOVE 31320 ............................
$450.00
TR-~C/AC~/MS
.....................................................
~
$600.00
TR-6/AC-4/MS4 SIX METER ................................
$500.00
T R 4 NOISE BLANKER .......................................... $ 50.00
NEW ENGLAND'S HAM HEADQUARTERS
Sells & Services:
RV-3, RV4, RV-4C VFO
R-4A RECEIVER
R 4 B RECEIVER
R 4 C RECEIVER
T4XB TRANSMI
.................. $350.00
T4XC TRANSMITTER WITH AC-4 P/S . . . . . . . . . $375.00
2 8 OR 2C RECEIVER .................................................. $150.00
Our large inventory also includes kits, amateur radio
publications and the largest selection of used equipment in the Boston area.
ABOVE DRAKE TRADE-IN ALLOWED TOWARD ANY NEWBOXED LATEST MODEL ATLAS, DRAKE, COLLINS, SWAN
EQUIPMENT. WE PAY SHIPPING ON ALL NEW EQUIPMENT TO YOU U.P.S. SHIP YOUR TRADE-IN PREPAID
TO US VIA U.P.S. TELL US WHAT YOU WANT. WRITE OR
PHONE BILL SLEP (704) 524-7519.
ELEC'FmO-C-
Our business is devoted entirely to Amateur Radio!
CO
P. 0. BOX 100, HIGHWAY 441, DEPT. HR
OTTO, NORTH CAROLINA 28763
.
L
APOLLO "SHADOW BOX ENCLOSURES"
are fabricated of heavy. cold rolled steel. The front panels are o f
20-guage brushed chrome steel; some models are line screened
and have a red Rocker DPDT switch installed w i t h gold plated
contacts and terminals. Covers are baked on Wrinkle enamel.
All cabinets are completely assembled a n d supplied w i t h four
rubber feet riveted in. Individually packed i n a heavyduty. corrugated mailer carton.
Chassis C t h r u M a r e CRS.
nickle.plated over copper f o r excellent RF conductivity.
PRODUCTION CABINETS T O
YOUR SPECIFICATIONS ON SPE.
ClAL QUOTATION; 250 PIECE MINIMUM. WRITE FOR QUOTATION.
MODEL WIDTH.HUCHT-DEPTH
A
5 k 2.1,~ 3
AA*
4 x 3 7/16 x 3.H
EB.
C
~ ~ l . & ~ ~ ; ; ~ X
HA
Dl
J
K
L
M
NA
4 25
5Y)
5.55
34'4
7 4 x 3.H x 5
z.;2t'
:.;58,.i27,1,16
7.y2 4.11~ 10
F
G
RESALE
NET
10.1116 x 3.5116 x 9
5-H x 5.% x 4
Mtg. bracket set for D
5 x 3-% x 5 %
4 4 x 7 4 x 11
11 H x 6.H x 12.3
11-'h a 6.h x 16%
12.lh x 5.h x 12.1116
11.15
11.15
7.85
.40
8.35
15.00
22.95
24 40
23 80
-hfl87 ,
;
* ,
"L"
package enclosure "Shadow Box"
mach~nedwlth. 2.50239, 1.Pllot
Ltght. 3 Rocker Sw~tches.and 2.
Knobs
*.OW alurnlnurn cover & chassls wlgralned panel
'*Mob~lmountlng ava~lable
L
pkg. $33.00
APOLLO PRODUCTS by ''KThge Twig"
.
BOX 245
94
VAUGHNSVILLE, OHIO 45893
Phone (419) 646-3495
NEW SSB & CW FILTER
INCREASE YOUR TALK
POWER 1 0 TIMES
QRM & QRN on both CW &
SSB. Features include 100
hz CW filters, 1500 hz SSB
filters, 3 w a t t audio amp.,
and built i n AC supply.
$59.95.
Other CW
SSB
f ~ l t e r sava~lable.
sion wtthout distortion allowing you to cut through
QRM & QRN. Features include volce tailored
re.
sponse f o r added punch and
solid state switching
for
long battery life. Requires
two 9V batteries (Not included) $59.95.
january
1976
Evening Phone (419) 646-3495
The NEW DE-112 regulated
supply has an output of 12
:p
it1:$5%
lh a n d % watt
RESISTORS
l ~ ~ ~ , " , t p ~ ~
ma' and
at
A' 159'95'
One year warranty and l5
day return privilege. Add $2
EEkdq:,","!
$h$l~,"zE~,"n",
is available. Write
for new
Values f r o m 10 o h m through
1 M e g i n multiples of 10.
12* 15, 18. 22, 27* 33, 39.
47, 56. 68. & 82. 4c each.
5 per value. $5 min. ppd.
Quantity discounts & assortments are available.
More Details? CHECK-OFF Page 102
L
YOUR CALL SIGN CUSTOM ROUTED into natural 5/s" x 5 % x 20" redwood. Choice black
or whlte letter~ng.One side $7.50. both $12.50
ppd. Tony Vltolo. WB4BKV. 1967 Tanglewood
Drive. Snellville. Ga. 30278. Other slzes on
request.
UNIVERSAL
TOWERS
-
PC 2406A MODU-CLOCK, LED Clock Kitl Six
Digit, 12/24 Hour, XTAL Time Base. Includes
Drilled. Plated PC Board and Instructions.
Thousands sold nationallv! Satisfaction Guaranteed! Order now. 48 h o u r Shipping! Only
$7.95. REL Electronics, 3511 Lynette Dr..
Amarillo, Texas 79109.
i
FREE STANDING
ALUMINUM TOWER
',
10' t o 100'
Prices f r o m $110.00 (309
MANUALS for most ham gear made 1940/65.
some earlier. Send SASE for specific quote.
Hobby Industry, W0JJK. Box H-864, Councll
Bluffs. Iowa 51501.
I
MOST
POPULAR
-
STOLEN: IC-230 (No. 240 1926). Heathkit
HWA-202.6 Colinear, and Data Tone 2 touch
tone encoder. Stolen from my car in Tampa,
FL on Oct. 31. 1975. Report filed with Hillsborough County Sheriff Dept. Bud Holman.
WA4ASJ, P. 0. Box 698, Vero Beach, FL 32960.
HAM TOWER
EVER MADE!
-
-
SUPERDESIGNED
New electronic roducts
for the Ham & Workbench. ~weep/~!!~/~unction Generator. Power s u ~ p l ysplitter
converts
.
single supply t o dual source. Speech compressors. More! Free Catalog. MINITRON. Box
184. Anoka. Minn. 55303.
REQUEST
-
NEW CATALOG
SB-104 OWNERS CLUB
Expanding its horizons to include the HW-104 and the new Heath
2 meter equipments. Newsletter, builders
guides, modification information and other
services on current Heathkit amateur equipments. Send SASE for details to Chuck Harrison, RD 2 Box 1. North Stonlngton, CT 06359.
0F
TOWERS &
ANTENNAS
-
TS413 SIGNAL GENERATOR, 75 kHz t o 40
MHz, decade attenuator, metered output, $80.
TS-419A generator. 900-2100 MHz. $140. HP612A generator 450.1230 MHz. $550. HP.207H
Univerter. $120. HP-41OB VWM. $75. J i m
Walter. 2697 Nickel St.. San Pablo. Ca. 94806.
For only $39.95
Midwest Ham Headquarters
For Over 36 Years
HAMS! M i t e For Free Cetalog
and W~olesalePrices!
STOLEN in Chicago area on 10-25.75. KDK
144-10SX Serial $5446. Nick Kalafice. W0OZZ.
117 West Glencrest Drlve, Mankato. Minn.
56001. 507-387-2279.
Our new F G - 2 Function Generator k i t
gives y o u all five o f the most useful
waveforms f o r design and testing a t one
f o u r t h t h e cost o f previous similar in-
ELECTRONIC DISTRIBUTORS, INC.
-
1960 Peck
KLM PRODUCTS. Larsen ants., Icom, police
and fire scanners. Send for prices. Not glven
over phone. N a m i d Electronics. 61 Bellot
Road. Ringwood, N. J. 07456.
struments. Thanks t o improved IC's t h e
F G - 2 n o w features amplitude stability
o f 2 1 d b over a n y range, Sine wave
distortion o f less than 1% f r o m 20 Hz. t o
20,000 Hz. and an o u t p u t o f 4.0 V o l t s
peak-to-peak w i t h adjustable offset. The
offset selector lets y o u p u t t h e positive
peak, negative peak, o r t h e center o f t h e
waveform o n D C ground. The D C coupled
circuit keeps t h e waveforms i n exactly
Muskegon. M I 49441
Tel: 616-726-3196
TELEX: 22-8411
-
SELL: SSTV Sumner 3KB Keyboard. Excellent.
$325 firm. RTTY CV-89 T.V.. excellent, $125
firm Write no hone. R. Hanson. WB2DHL.
RD 3. 0sw;go.
b f Y. 13126.
-
LEARN CODE I N A FEW DAYS with audio
reflex method of teaching letters, numbers.
punctuation. One hour cassette only $7.00.
Guardian. 20 E. Main St., Ramsey. N. J. 07446.
-
NOVICE. GENERAL AND CODE COURSES are
available at the Harrison. New York School of
Continuing Education. 10 two hour sessions
one evenin a week. Contact George Buchanan
WBZFVX. (814) RO.1-4183.
the same position n o matter what the
level c o n t r o l setting.
PAYING 5% OVER BEST OFFER for Eimac/
Varian tubes, ham and commercial gear, etc.
Ted Dames, WZKUW. 308 Hickory St., Arlington. N. J. 07032. (201) 998-4246.
I
MANUALS for Govt. surplus gear, $6.50 each:
URM.25D, OS-8C/U. SP.600JX. TT-63A/FGC,
TS-497R/URR. BC.348J. N. 0.TS-382D/U. ALR5.- ~h&&n.d;'
more availabL. ~ e n d - 5 0 C'(coin)
for 22.page catalog. W31HD. 7218 Roanne
Drive. Washington.
D. C. 20021.
-
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THE 21ST ANNUAL HAM AUCTION. America's
Largest. Saturday. March 13. 1976, at Lucas
County Rrecreatlon Center. Toledo. Ohio. Auction flea market, commercial displays, prizes.
8:0d a.m. t o 5:00 p.m. $1.50 advance. $2.00
after March 1st. Send SASE. Talk-in 146.52.
Toledo Mobile Radio Association, Box 273.
Toledo. Ohio 43696.
-
REGULARLY $1,200.00.
NOW ONLY $995.00
EACH. Hammarlund HQ215 solid state HAM
BAND/general coverage receiver mint. at
$325.00. Send self addressed stamped envelope for large list of used gear to: HCJ Electronics 8214 E. S rague. Spokane. Wa. 99208.
Phone '509-924.23f3.
RARS 1976 ANNUAL HAMFEST, April 11. For
details write: RARS, Box 17124. Raleigh, N. C.
27609.
-
-
I
NEW YEAR SPECIAL!
Complimentary issue of
THE BIG LIST from
Buyers d. Sellers. Check off #329.
BUYERS L S t L L E f f i
P . 0 Box 7 3
*more
station
Boston. Mass. 02215
More Details? CHECK-OFF Page 102
817-536-8777
I II
I
Gray impact plastic care 5% x 6%x 2%.
115 Volts 60 cycle power supply included.
FG-2 F u n c t i o n Generator K i t
3.0 lbs.........$39.95 PPd
shipping weight
I
SEND FOR OUR
NEW 1976
CATALOG
RMS CORPORATION
THE ELECTRONIC STORE
675A GREAT ROAD (ROUTE 119)
LITTLETON. MASS. 01460
(617) 4864973
ICOM
MATRIC-KEYERS
HUSTLER
ANTENNA SPECIALISTS
LARSEN
CONSIGNMENT EQUIP.
KLM
RADIO PUBLICATIONS
LARGE INV. COMPONENTS
USED EQUIP.
1495 t o Rte. 119 Qroton Exit 19
2 miles on Right
SALE
KWM-2. AC supply. 30L-1, $1150.00.
Phone 214-792-1378. J. R. Scott, No. 18 Tamar
Dr.. Texarkana, Texas 75501.
YOUR AD belon s here too. Commercial ads
4 0 t per word. Ron-commercial ads 104 per
word. Commercial advertisers write for spectal
discounts for standing ads not changed each
month.
0.1 Hz. to 100 KHz.
kits
listing this a n d other unique
q'l
R € Err
by
simply circling
on t h e
our number
card.
r e a d e r service
SOUTHWEST T E C H N I C A L
PRODUCTS C O R P O R A T I O N
DEPT. H
MULTI-2000
219 W. Rhapsody
San Antonio. Texas 78216
-
-
january 1976
-
95
I
2 CHANNEL OPERATION
FREQUENCY RINGE 144-148 MHz
1 WATT MINIMUM POWER
OUTPUT @ 12.5 vdc
5 0 OHM RF OUTPUT IMPEDANCE
8 X MULTIPLICATION FACTOR
NARROW BAND FM f 5 KHz
RUGGED BALANCED EMITTER
OUTPUT TRANSISTOR
SIZE 3%" L X 1%'' W X
1" H
>
TESTED & FULLY ASSEMBLED
(Less xtals)
$32.95 p r i c e i n c l u d e s a l l p o s t a g e f e e s
I
rz,i*$
SUGGESTIVE?
SURF
THE DELUXE PORTA-PAK
NOT ONLY SUGGESTS
BUT DELIVERS:
ATTRACTIVE PACKAGE
DURABILITY PLUS
OPERATION ANYWHERE
$59m95
OVERNIGHT RECHARGING
PORTA-PAK IS THE ACCESSORY
THAT MAKES YOUR MOBILE RADIO
REALLY PORTABLE. AVAILABLE
FOR MOST F.M. TRANSCEIVERS AT
$59.95 WHICH INCLUDES CHARGER.
PORTA-PAK
P. 0. BOX 67
7%
the action and
adventure in
amateur radio:
WORLDRADIO
-monthly
publication-
trial subscription
next 2 issues $1
2120 28th St.
Sacramento, CA
9581 8 - W ~ A J Y
NEWS
MODEL 3 0 MORSE TO
VIDEO CONVERTER
CONVERTS RECEIVED M O R S E C O D E
F R O M Y O U R RECEIVER T O A V I D E O
P R I N T O U T O N YOUR T.V., N O O T H E R
DEVICES R E Q U I R E D
NO CRITICAL ADJUSTMENTS
ATTACHES TO ANY CW RECEIVER WlTH
B F 0 AND 3 TO 600 OHM AUDIO
SIMPLE LED TUNING INDICATOR
UNIQUE P L.L. FRONT EN0 INPUT FILTER FOR SUPERIOR SELECTIVITY
AUTOMATIC SPEED AND WEIGHT ADJUSTMENT TRACKS 8 TO 150 W.P.M.
SIMPLE CONNECTION TO YOUR T.V.
SET'S VIDEO AMP FOR EXCELLENT
PRINTS 8 LINES, FOR A TOTAL OF 256
CHARACTERS
TEXT SHIFTS UPWARDS AS MESSAGE
CONTINUES WlTH AUTOMATIC CARRIAGE RETURN AND LINE FEED
WILL ACCEPT PARALLEL ASCII WlTH
STROBE FOR MICRO COMPUTER APPLI-
a
RAOlOAM4URllb
00
AI
Dept. ::EL:
k
INC.
~ l l ; ; ~ ~ d ~ ~ ;
Order from your favorite electronics
dealer or direct from the publisher. All
d~rect orders add 51.00 sh~ppi~ig
and
handling per Callbook.
96
january 1976
BUILT IN AC POWER SUPPLY
RTTY INTERFACE AVAILABLE WlTH OR
WITHOUT VIDEO BOARD TO DRIVE YOUR
PAGE PRINTER (Extra Charge)
PRICE $299 50 DELIVERED I N CONTINENTAL USA
WRITE FOR BROCHURES
INFO-TECH INC.
P. 0 B O X 84
CHESTERFIELD, M I S S O U R I
63017
CASH
FOR
2-WAY
FM RADIO
TELEPHONES REPEATERS REMOTE CONTROLS,
TONE EQUI~MENT, 2 - W A ~TEST EQUIPMENT
Operational U n i t s Only
C o r n m i s s i o n s / F i n d e r s Fees
C A L - C O M SYSTEMS, INC.
701-51A KINGS ROW, SAN JOSE, CALIF. 95112
Telephone 24 Hwrs 408/998-4444
MODSET: precision modulation
measurements for AM-SSB, 0.2 to
300 MHz, $29.50 (Kit: $19.50)
D. R. CORBIN MFG. CO.
P. 0. B o x 44. N o r t h Bend, Ore. 97459
More Details? CHECK-OFF Page 102
Ham Radio's guide to help you find
your local Amateur Radio Dealer
California
Michigan
HENRY RADlO
9 3 1 N. EUCLID AVE.
ANAHEIM, CA 92801
714-772-9200
The world's largest distributor of
Amateur Radio equipment.
AUDIOLAND
36633 SOUTH GRATIOT
MT. CLEMENS, M I 48043
313-791-1400
All major brands, new/used
equipment & accessories.
HENRY RADlO CO., INC.
11240 W. OLYMPIC BLVD.
LOS ANGELES, CA 90064
213-477-6701
The world's largest distributor of
Amateur Radio equipment
ELECTRONIC DISTRIBUTORS
1960 PECK STREET
MUSKEGON, MI 49441
616-726-3196
Communication specialists
for over 3 7 years.
Colorado
RADlO SUPPLY & ENGINEERING
1203 WEST 1 4 MILE ROAD
CLAWSON, M I 48017
3 13-435-5660
1801 Chalmers, Detroit, M I
48213, 313-371-9050.
C W ELECTRONIC SALES CO.
1401 BLAKE ST.
DENVER, CO 80202
303-573-1386
Rocky Mountain area's complete
ham radio distributor.
Illinois
SPECTRONICS, INC.
1009 GARFIELD STREET
OAK PARK, IL 60304
3 12-848-6778
Chicagoland's Amateur Radio
leader.
Indiana
HOOSIER ELECTRONICS
P. 0. BOX 2001
TERRE HAUTE, I N 47802
812-238-1456
Ham Headquarters of the Midwest.
Store in Meadow Shopping Center.
Kansas
AMATEUR RADIO EQUIP. CO.. INC.
1203 E. DOUGLAS
WICHITA, KS 67211
3 16-264-9166
Assisting the Amateur
since 1949.
ASSOCIATED RADlO
8012 CONSER P.O.B. 4327
OVERLAND PARK, KS 66204
913-381-5901
Amateur Radio's Top Dealer.
Buy - Sell - Trade.
Massachusetts
TUFTS RADlO ELECTRONICS
386 MAlN STREET
MEDFORD, MA 02155
617-395-8280
New England's friendliest
ham store.
Minnesofa
ELECTRONIC CENTER, INC.
127 THIRD AVENUE NORTH
MINNEAPOLIS, MN 55401
612-338-5881
ECI is still your best buy.
Missouri
HAM RADlO CENTER, INC.
8342 OLIVE BLVD.
P. 0. BOX 28271
ST. LOUIS, MO 63132
800-325-3636
Call toll free.
Nebraska
COMMUNICATIONS ENGINEERING
4341 N. 61ST
LINCOLN, NE 68507
402-464-7571
See us for service and
modifications.
New Jersey
ATKINSON & SMITH, INC.
17 LEWIS ST.
EATONTOWN, NJ 07724
201-542-2447
Ham supplies since "55".
New York
ADIRONDACK RADlO SUPPLY, INC.
185 W. MAlN STREET
AMSTERDAM, NY 12010
518-842-8350
Yaesu dealer for the Northeast.
CFP COMMUNICATIONS
2 1 1 NORTH MAlN STREET
HORSEHEADS, NY 14845
607-739-0187
Jim Beckett, WA2KTJ, Manager
Dave Flinn, W2CFP, Owner
Ohio
UNIVERSAL SERVICE
114 N. THIRD STREET
COLUMBUS, OH 43215
614-221-2335
Give U.S. a try when ready t o buy.
Pennsylvania
ARTCO ELECTRONICS
3 0 2 WYOMING AVE.
KINGSTON, PA 18704
717-288-8585
The largest variety of crystals
in N. E. Penn.
ELECTRONIC EXCHANGE
136 N. MAlN STREET
SOUDERTON, PA 18964
215-723-1200
New & Used Amateur Radio
sales and service.
HAMTRONICS, INC.
4033 BROWNSVILLE ROAD
TREVOSE, PA 19047
215-357-1400
Same location for 25 years.
South Dakota
BURGHARDT AMATEUR CENTER
124 FIRST AVE. N.W. P.O. BOX 7 3
WATERTOWN, SD 57201
605-886-7314
America's most reliable Amateur
Radio Dealer - Nationwide!
Texas
ALTEC COMMUNICATIONS
1800 S. GREEN STREET
LONGVIEW, TX 75601
214-757-2831
Specializing i n ham equipment for
the Ark-La-Tex.
Virginia
ARCADE ELECTRONICS
7048 COLUMBIA PIKE
ANNANDALE, VA 22003
703-256-4610
Washington
AMATEUR RADIO SUPPLY CO.
6213 13TH AVE. SO.
SEATTLE. WA 98108
206-767-3222
Amateur center of the
Northwest.
-
january 1976
97
I Semiconductor Supermarket
ALL DEVICES AND COMPONENTS ARE FACTORY FIRSTS
- NO SECONDS OR FALLOUTS
TROPICAL
HAMBOREE
1
Bayfront Park Auditorium
Miami, Florida
1
VHF PRESCALER DEVICES AND KlTS
- ..- - . --..-300 MHz 10 prescaler $15.95
9582
Preamo/nate .......................$3.25
95H91 -.............................. $15.95
W~debandpreamp trans. 1.80
250 MHz SCALER KIT includes
95H90. 2N5179 Circuit Board.
small arts and ~ n s t r u c t ~ o n s .
~ e ~ u ~ r5Ve spower source
not included .
ONLY $24.95
500 MHz Prescaler
..$43.95
-
500 MHz scaler ..............
$21.95
I
24-25
I
FETs
MPFlO2
J FET ..............................................$60
MPF105/2N5459
JFET ......................................... f.96
MPF107/2N5486
JFET VHF/UHF .................. $1.26
MPF121
Low-cost dual gate
VHF RF ..................................$1.40
Quantity
3
3
3
3
DADE RADIO CLUB
P0
I
I
BARGIN SQUARE
.15 ea.
.55 ea.
.55 ea.
.99 ea.
.36 ea.
.36 ea.
.20 ea.
.30 es.
TEKTRONIX
OEI
CEI
GENERAL
RADIO
ETC.
DC
SCOPES
RECEIVERS
AUDIO
VIDEO
COUNTERS
SIGNAL GENERATORS HF/VHF/UHF
MICROWAVE
RECORDERS
SIGNAL CONDITIONING TELEMETRY
POWER SUPPLIES
I f your organization has test equip. requirements
call or write EEB. Inquiries welcomed.
10 for
10 for
10 for
10 for
10 for
10 for
10 for
10 for
432-450 MHz TRIPLERIDRIVER
$19.95
CABINET for xcvr or other projects
$27.95
SEND SASE FOR CATALOG. INCL RCVRS,
PREAMPS. ETC
-
D E l Spectral Dlsplay U n i t , M o d e l
TDU-4 - 30 M H z center frequency
B a n d w l d t h is 3 MHz.
-
CIRCUIT SPECIALISTS CO.
Box 3047, Scottsdale, AZ 85257
I
1
..*e
..
*
I
New in factory cartons
$295.00
Other Display Un~tsinclude TOU.3, Nems Clarke/
Vttro Model SDU-200. -300
Center freq. 30
or 21.4 MHz (Spec~fy)- New and Used
Prices range $95 $295.
-
-
CLOSE OUT SPECIAL - $19.95
while they last ppd. USA
ARR-52
Easily converted to 2-metu
FM. Now set for 163.173
MHz, 16 channels. Includes
schematic diagram and conversion details. As described
i n the Surplus Sidelights
Column, (Pg. 58 Oct. CQ).
OVER 400 SOLD
SOLIDRECEIVER
STATE
VHF
Electronic Equipment Bank, Inc.
516 M i l l Street, N.E. Vienna. Virginla 22180
(703) 938-3350
january 1976
Please add 406 for shipping
I
1
BankAmericard & COD Welcome
98
SEND FOR
FREE CATALOG
TOUCHTONE
ENCODER
I
I
I
I
This Month's Special
-
450 PA, using new RF power
modules
$79.95
$1.25
5.00
5.00
9.90
3.00
3.00
1.50
3.00
I
i
2M, 200 MW FMICW EXCITER
$39.95
Frequency
To 20 MHz
To 20 MHz
To 75 MHz
To 200 MHz
To 200 MHz
I
EEB
Announces New Industrial Division
NEW FM XMTR KlTS
................................$1.86
ALSO
1200-2 ONLY $2.00 ea.
7400
7490
7475
7447
7473
7474
14-PIN S k h
1 6 P I N Skts
BOX 570073, BISCAYNE A N N E X , M I A M I , FLA 33152
f
................................$1.95
Color
Red
Red
Yellow
Black
Black
Core
T50-2
768-2
T50.6
750-10
T44-10
3
I
- 52 00
.............................. 198
................................. 1%
TOROID CORES
PRICE - $1.00 PACKS
MANUFACTURER'S EXHIBITS
GIANT HAMBOREE SWAP SHOP
HAMBOREE PRIZE AWARDS
ARRL GENERAL SESSION (Sunday)
REGISTRATION
ME3007
Dual-gate
40673
3N140
Dual-gate
3N141
Dual-gate
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FEATURES:
-
Crystal Controlled
sized Tones.
Digitally Synthe-
;
I
Low Current Drain CMOS Logic.
RFI Immune.
16-Button Tactile Feedback Keyboard.
Will Interface to Transceivers Using
Dynamic Microphones with Only Two
Wires.
Provisions for Three Wire Interface
Are Provided.
Gold-Plated Keyboard Contacts Provided for Maximum Reliability.
Operating Voltage Range 9-18VDC.
Size: 2.1" x 2.1" x .250*l Without Case.
2.1" x 2.111 x .312" With Case.
2" Square Velcro Available for C o n
venient Mounting
Dashboard Sun
Visor
Radio Etc.
Touch-Tone Encoder ........... $29.50
case ............................................... $2.00
Velcro ........................................... $ .50
-
-
-
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)
)
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OHlO RESIDENTS ADD 4.5% SALES TAX
j SEND CHECK OR MONEY ORDER TO: j
j The Barber Corporation j
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P. 0. BOX 271
WAYNESVILLE, OHIO 45068
513.897.2926
I
More Details? CHECK-OFF Page 102
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FM!PUNCH
AM-cw-ssB
u,
.IV
b
Rf It*'010
_&~*^d*c
Case Dimensions
A 2-112" H x 3-7/8" W x 4" Deep
B 2-1/2" H x 5-1/2" W x 7'' Deep
C 2-1/2" H x 5-1/2" W x 11" Deep
bl.
Model
R FA-3-40-HB
RFA-3-60-HB
RFA-3-110-HB
RFA-3-200-HB
RFA-10-75-HB
R F A - 10 - 10 0 - H B
RFA-10-150-HB
RFA-25-150-HB
RFA-25-200-HB
RFA-1-75-HB
RFA-1-25-HB
Drive
Power
3 watts
3 Watts
3 Watts
3 Watts
1 0 Watts
1 0 Watts
1 0 Watts
2 5 Watts
2 5 Watts
1 Watt
1 Watt
Output
Power
Current
Drain
Max.
Drive
Case
Size
Price
4 0 Watts
6 0 Watts
1 1 0 Watts
2 0 0 Watts
7 5 Watts
1 0 0 Watts
1 5 0 Watts
1 5 0 Watts
2 0 0 Watts
7 5 Watts
2 5 Watts
4 Amps
7 Amps
1 4 Amps
2 4 Amps
8 Amps
1 3 Amps
17 Amps
1 7 Amps
22 Amps
9 Amps
3 Amps
5 Watts
5 Watts
5 Watts
5 Watts
1 5 Watts
1 5 Watts
1 5 Watts
4 0 Watts
4 0 Watts
5 Watts
4 Watts
B
B
C
C
B
B
C
C
C
B
A
$129.95
159.95
199.95
349.95
129.95
189.95
239.95
249.95
299.95
179.95
99.95
Dealer and Dlstrlbutor
Inquiries solicited
All models will operate with
reduced output from as little as one watt drive.
Amplifiers are supplied pre-tuned for band portion in which they are to be used.
Comparable models for 6 and 10 meters
L
are also available.
2204 Foster Avenue
More Details?CHECK-OFF Page 102
-
Wheeling, Illinois 60090
3 12/392-6030
january 1976
rn 99
we are omc.al dlStrlbutom for
Newtronics BELT 2 Meter Mobile Antenna
Millen 2KW Transmatch ............................. Write
Signal Elec. Telegraph Sounder, never used,
with trunk l i p mt. 3.4dB gain. 143 t h r u 149
sird wattmeters and elemanh.
$19.95
Wattmeters & most elements
~ ~ e z e ; . ~ C d " ~ ~ C , b i ~ e , " r ~ i ~ 5 0 ; ~ ~ ~ ~ ~ ~~;~~~; - c ~ ~ - - - - - - - - - i i
--,
now in stock.
.
-Distributors for Tri-Exand Rohn Towers.
I NEW ITC Multi 5000. synthesized
FM.
IC-230 - Call or write .....
-- $489.00
AM, USE. LSB, adjustable 1-80 'watts
Astatic Model T.UG8-Dl04 ~ i k e - ' w / s t a n d
$695.00
$48.60
13.6 Volt, 1
rdered I
SPR-4 Solid Sta
Microwith above
$55.00
Bid
RF thruline
~ ~ ~ ; : ~
j
1
Drake
1
,[
1
L----------
MS-4 Speaker
AC-4 Power S
TR.22C. 2 m
ver
with NiCads, case . . . . . . . . . . . . . . . . $229.35
TF(.~C. 10 thru 80 M. SSB. AM;,,CWs,&;:;
celver . . . . . . . . . . . . . . . . . . .
L-4B Linear Amp w/P.S.
tubes..... $ 825.00
MN.4 Antenna Matching Network ..... $1 10.00
DSR.2 VLF thru HF Digital Synthesized Corn
munications Lab Rcvr . . . . .
f2950.00
-
rcvr.
NEW .. SSR-1 Gen: C o v : , , s o l i d , , , ~ ~ ~ j ~ { ~ ! &
Order all y o u r o t h e r Drake products through
Barry!
-
C.D. Ham 11 Rotator
Ameco Model PT Preamp. factory wired $69.95
Regency HR.6 6 m t r FM transcvr. Brand New
Reg. $239.95 . . . . . . . . . Now $175.00
DX Engineering Speech Compressor for Collins 32s xmtr $98.50; for Collins KWM2
$98.50: for Drake TR44C) $ 128.50.
BARRY BUYS UNUSED TUBES AND VACUUM
CAPACITORS. Send Your List. Tube Headquarters. Diversified Stock. Heavy Inventory
of Eimac tubes, chimneys. sockets, etc.
3-5002 $63.00 or 3.4002 $50.00.
Johnson 154-10 o r equal. Single section 23
thru 347 pF for KW transmatch. Replaces
Millen 16520 .........................................$36.00
Johnson 229.202 or equal. 18 m H variable
inductor 10 to 80M for KW transmatch $39.00
Johnson 229.203 or equal. 28 m H variable in.
ductor 10 to l6OM for KW transmatch
$39.00
Includes brushed aluminum-pin with your call!!
NEW ARRIVALS
-
New Improved
$139*95
$159.95 net SAVE $20
Motorola Rcvr Model R.220,URR
freq. 19.74
thru 237.97 MHz. Continuous tuning
AM/
8 conductor cable for HAM II o r C D 4 16,4/ft.
FM/CW. Excellent condit~on with comolete
manual - Lab certified
.... $450.00
ANTENNAS
~ ~ - a3 other
6
beams instock,
National NCX.500 ~ransceiv;;
(10-80m) with
Nat'l matching AC supply
very good conwrite or call.
Antenna Specialists' amateur and marine an.
dition
Lab tested with manual ... $275.00
tennas stocked in depth.
Hallicrafter FPM-300 Transceiver (80.10m)
~~t~~~~ specialists H M . ~~
~ D U C ~bY . ( 2 b~ . with
~
manual.
~
Mint condition.
... $395.00
5/16".32 for Motorola/Johnson, etc.)
$7.00
Hallicrafter SX-130 Gen. Cov. Ham Rcvr, excellent,
very
clean
condition
with
manual
Antenna Speclalists HM.5 Rubber Ducky. (w/
PL259 for TR-22C, etc.) . . . . . . . . . . . . . . . . $7.00
$ 159.00
CushCraft Antennas now i n stock.
Collins 7 5 S 1 Receiver with Collins 32s-1
New Rlngo Ranger ARX.2. 6 dB base anTransmitter and Collins 516F2 Power Suptenna
..................... $26.50
ply. Sell as package with manuals
..................... write or good
call
condition
HyGain I/. wave 2 ~ ' ~ plane
r d .............. $13.00
han.
H i Power ~ a t c h b o xfor comrn'l use
HyGain EN86 Deluxe Balun ..................... $ 15.95
HyGain 18 AVT/WB 10.80 metem vertical
dles up t o 10 kW (10-160 meters)
$350.00
$97.00
Heathkit 58610. SB630 .......................... Write
Newtronics G6-144A fixed station antenna
Johnson Matchbox. 275w. w/SWR, mint
6dB gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $52.00
$139.00
-
-
-
-
Tubes f o r worldwide and
domestic, commercial serv i c e . ~ a r g es t o c k s o f
meters and capacitors.
I
TEN-TEC DISTRIBUTOR
Barry.
KR50
-
Order
through
~~~~~~p"dc~~~~it~~ti0n,,
r---------------------------------7
1
1
I
1
'
I
I
NPC POWER SUPPLIES
Model 102 115V AC Input . 12 VDC
I
4
I
1
'
amps max. out
.. $25.00
Model 104R r e g u l a t e d " 1 3 . 6 " ~4A
~ ~ cont. )
6A max.
$49.00 I
Model 1 0 8 ~-l i 5 . ~ ~ ~ / 1 3 . 86 1 " ~ ~ ~
amps continuous 12 amps surge. Regulated
$72.00 )
1
------------------
1
LARGE STOCK!
B & W Miniductors - A i r
Dux coil stock
Milien
Components
Parts.
WE HAVE VIBROPLEX I N STOCK1
Orig. Deluxe V~broplex "bug"
...... $46.70
Vibroplex Vibro Keyer Standard ........ $30.75
Vibroplex Vibro Keyer Deluxe ............... $39.95
-
Store Hours
Saturday, 10 a.m.
DEPT.
I We're Fighting
12-7670
-
Thumbwheel S w i t c h e s EECO Model
805M 0 to 9 BCD and C o m p l i m e n t
(These switches a r e used but a r e in
good condition a n d are p e r f e c t for
Ham Use)
Price:
1-10 $1.95, 11-25 $1.65, 26 and
up $1.25
for '76
FOR FREQUENCY S T A B I L I T Y
Tubes New
Depend o n J A N Crystals. Our large stock
o f quartz crystal m a t e r ~ a l s and componentsassures Fast Delivery from us!
6:00 p.m.
MICROCOMPUTER INTERFACING WORKSHOP March 12-13, 1976. A two-day
workshop based on the popular Intel
8080 mlcro processor. T h ~ s course IS
sponsored by the Virginia Polytechnic
lnstltute and State University Extension
D~visionat the VPI Center in Reston, Va.
(near Dulles Airport). This workshop will
include many hours of experience in programming and interface construction with
over 12 operating microcomputers for
participant use. For more information
contact Dr. Norris Bell. V.P.I. and S.U.
Cont~nuingEducatlon Center, Blacksburg.
Va. 24061. 703-951-6328.
DIGITAL ELECTRONICS FOR AUTOMATION AND INSTRUMENTATION. March
21-26 whlch IS a hands-on laboratory/
lecture course coverlng b a s ~ cdigital electronlcs as well as data communications
and Interfacing using asynchronous serial
techniques. It is held at Virginia Poly.
technic Institute and State Un~versity in
Blacksburg. Va. and is sponsored by the
American Chem~cal Soc~ety. Educatlon
Division. 1155 16th St.. N.W.. Washington,
D. C. 20036. (202)-872-4528.
Tubes Used But OK
52.50
$2.75
$ 3.75
More New Tubes
$15.00
4X150A
$18.00
4C150G
$22.00
4CX25OF
4CX250B
$24.00
I RF Transistors
4 p.m.
Monday-Friday, 9 a.m.
Add shipping-excess refunded-Quoted FOB N.Y.C.
I This Month's Specials I
I Inflation
I
I
CRYSTAL SPECIALS
Frequency Standards
100 KH,(HC 131U) . . . . . . . . . . .
1000 K H Z ( H C 6lU)
'
-
.------------------------------------------------------------------------------------I BA R R Y 512 Broadway NY, NY 10012
'~ ~ I ~ - W A - S - ~ O O O
.
ELECTRONICS
TELEX
1
------I
itching
$74.95
B & W 3
r 0.300
MHz 520,O-10, 100,300, 1000 Watts
$167.50
B & W 374 Dummy Load.Wattmeter 0-300
MHz 52!! 0-15. 50. 300. 1500 watts . . . f 195.00
Sockets for 8072. 8121. 8122
........... Write
EBC Jr..2 meter FM synthesized XCVR $599.00
MC Jones ~ o d .575.5 Micro Match SWR
bridge. N Connectors. For use with 2001,a
meter. New value $100.00 ........................ $24.95
...........
>
$4.50
4.50
Almost all C B sets. TR o r Rec . . . . . . $2.50
(CB Synthesizer Crystal o n request)
Amateur Band i n FT.243 . . . . . . . ea. $1.50
. . . . . . . . . 41$5.00
80.Meter-. . . . . $3.00 (160-meter not avail.)
For 1st class mail, add 20' per crystal. For
Airmail, add 25'. Send check or money
order. N o dealers, please.
Bob When 6 Son Electronics, k.
2400 Crystal Or..
Ft. Myers, FIa. 33801
All Phones: (813) 9362397
Sond 10' for MI catalog
100
january 1976
,,+"'
~ ~ ~ ~ t.~ : < +
Wire:
RGl74/U 24Awg. 7/34 Strand. These are
in 5 foot lengths.
Price per 50 lengths $6.95
Price Der 100 lengths $11.95
Spectra Strip ~ y p ; 2444 16 conductors
7 strand 24 Awg.
Price 1 t o 25". .39"
-
THE EASY WAC
Based
on
modern
p s y c h o l o g i c a l techniques
This course w i l l
take y o u b e y o n d 1 3
w.p.m. I n
LESS T H A N
H A L F T H E TIME!
-
49-95
Album contains
three 12" LP's
2% hr. instruction
.
lN o Books T o Read
visual Gimmicks
T o Dlstract Y o u
u
,,
Listen A n d .earn
lNO
Available i n Cassette also f o r o n l y $10.95.
2543 N. 32ND ST.
PHOENIX. ARIZONA 85008
PH. 602-957.0786
508 East Washington St.. Arcola. l L 61910
More Details? CHECK-OFF Page 102
ouble dutY*
The HAL
.-A
I-or rne- prlce or arl vlulllary neyooaru,
yuu can send
both TTY and CW. At the flick of a switch, send TTY a t all
standard data rates, or perfed CW a t 8-60 wpm.You get
complete alphanumeric and punctuation keys, a "DE-call
letters" key, even a "QUICK BROWN FOX..." diagnostic key
for llY. In both rnodes,you have a three-character buffer
for bursting ahead (larger buffers available), and in the CW
mode you can adjust the dot-to-space (weight) ratio to your
liking.
Like all HAL products, the DKB2010 is built t o commercial standards-yet this solid-state unit is available a t a price
youll appreciate. It's like getting two keyboards for the price
of one.
For all the details, write today. Well answer you on the
double.
1
---
&L
.
.
a
s
.
HAL Communications Corp., Box 365,807 E. Green St.
Urbana, Illinois 61801 Telephone: (217) 367-7373
Picture the HAL RVD-1005 video TTY unit in your station.
And start enjoying silent, trouble-free TTY reception.
The RVD-1005 converts the output of any TU into a clear,
easy-to-read T N video readout. The output signal can be
fed to a TV monitor-like the RVD-2llO monitor shown-or,
with slight modification, any standard TV receiver. The features speak for themselves. We've included everything the
serious amateur requires for TTY receiving a t its best.
Best yet, the RVD-1005 is built to commercial standards,
yet is priced at a level the amateur l T Y enthusiast will find
very affordable.
For a n in-depth
picture,
write today for complete
information.
HAL Communications Corp.. Box 365,807 E. Green St.
Urbana, Illinois 61801 Telephone: (217) 367-7373
AqerTisers
v
check-off
...for literature, in a hurry -- we'll
rush your name to the companies
whose names you "check-off"
Place your check m a r k i n t h e space between
234
name a n d number. Ex: Ham Radio
.d
INDEX
A.C.E. - 392
A & W - 359
Adva - 265
Aldelco - 347
Apollo .011
Aptron - 380
Atlas - 198
Atronics - 382
Babylon - 014
Barber . - 383
Barry *
Budwig - 233
Bullet
328
Buyers &
Sellers - 329
022
CFP _
Cal-Com - 282
Circuit Spec. _ _ 026
Communications
Speclallsts
330
Communtcat~on
Speclalttes
369
Corbln
349
Cush Craft
035
D.D
269
Dames
324
270
Data Slgnal
Dentron
259
Drake
039
Ehrhorn
042
Elmac
043
Electrograftx
371
044
Elect Dlst
Elect Equlp
Bank
288
ELPROCON
301
Epsilon - 046
Erlckson
047
Falr
048
Fluke
049
Genave
168
Hal - 057
254
H a l Tronlx
H a m Radlo
150
Hamtronlcs
246
Heath
060
Heights -. 061
Henry
062
Hewlett.Packard - 281
Htckok
402
Hlldreth
283
Hosfelt
390
Howard - - 361
403
HUFCO _
H y Galn _
064
lcom .
065
Info Tech
351
Int Crystal
066
James
333
J a n - 067
Janel
068
Jensen Tools
293
K.Enterprises - 071
KLM
073
Kensco -. 394
Kenwood -- 3 4 1
K i n g Prod.
373
Levy - 291
Lyle _373
MFJ - 082
MHz - 394
363
Maynard .
M l n i Products. _ 395
M.Tech
357
Nattonal Multi.
.396
N. R. I.
397
N.E. Digital .
336
Northshore R.F. - 296
Optoelectron~cs
352
Palomar
093
Plnon
337
Porta-Pak - 274
Prultt - 365
RCA
312
RMS .
239
Callbook
100
Regency
102
Slep
232
262
S.W. Tech. _
Space
107
Specialty Comm.
Systems
318
Spectronlcs
191
Spectrum Int.
108
Stahler
142
Swan
111
Sys. Research
392
Telrex
377
Ten.Tec '
Topeka FM
115
Troplcal H a m
185
Trl-Ex
116
Trlplett
398
Tucker
113
Tufts
321
VHFEng 121
Vanguard
346
Vlbratrol
251
Va Polytechnic '
Vlsulex
399
Weber
400
Webster
255
We~nschenker
122
Welrnu
379
Wti~tehouse
378
Wllson
123
Worldradlo
186
Yaesu
127
*Please contact thls advertiser dlrectly
Lirnit
I5 ir~cltrtrics~
C
ic'clrrc'tt.
I
January 1976
Please
use
b e f o r e F e b r u a r y 29, 1976
Tear off and m a l l t o
H A M RADIO MAGAZINE
Greenvllle, N. H. 03048
- "check
NAME
CALL
STREET
CITY
STATE
102
ZIP
january 1976
off"
84
77
80
96
94
73
45
71
88
98
00
Budwig Mfg. Co. ............................................93
Bullet
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Buyers & Sellers . . . . . . . . . . . . . 90, 95
CFP C o m m u n ~ c a t i o n s. . . . . . . . . . . . . . . . . . . . . . . . . . .80
Cal-Com Svstems. Inc.
96
Clrcutt ~p;clallsts Co.
98
C o r n r n u n ~ c a t ~ o nSpeclallsts
s
2
C o r n m u n ~ c a t ~ oSnp e c ~ a l t ~ e sInc.
.
90
D R Corbln Mfa.
96
- Co.
Cush Craft
G3
Dames. Ted
Dentron Ra
Dynamlc Elect
Elmac. Div. of Varlan Assoc.
. . Cover IV
Electrograflx
88
95
Etectron~c D ~ s t r l b u t o r s
Electronic Equipment Bank. Inc.
98
ELPROCON
96
Epsilon Records
100
E r ~ c k s o nC o m m u n ~ c a t ~ o n s
103
92
Falr Radlo Sales
88
Fluke
General Avlatlon
75
Hal C o m m
01
Hal-Tronlx
93
H a m Radlo
82
Hamtrontcs. Inc.
96
Heath Company
52. 53
Helghts M a n u f a c t u r ~ n gCo.
90
Cover I I
Henry Radio Stores
Hlldreth Englneerlng
80
Hosfelt Electronics
90
Howard Mlcro Systems. Inc
77
HUFCO
82
Hv Galn Electronics Corp
48. 49
lc0m
5
Info.Tech
96
l n t e r n a t ~ o n a lCrystal Mfg. Co.. Inc.
35
83
James Electronics
Jan Crystals
100
Janel Labs
93
Jensen Tools
90
K.Enterprlses
51
KLM Electronics
87
Kensco C o r n m u n ~ c a t ~ o n sInc.
.
92
Trlo-Kenwood C o m m u n ~ c a t ~ o n s I. ~ c .
27
Klng Products
86
80
Levy Assoc~ates
Lvle Products
92
MFJ Enterprises
80
100
MHz Electronics
Maynard Electronics
93
M I ~ I Products
88
M Tech
88. 92
Natlonal M u l t ~ p l e x Corp.
85
Natlonal Radlo l n s t ~ t u t e
23. 93
New England Dlgltal Electronics
88
Northshore RF Technology
92
Optoelectron~cs
71
Paloniar Engineers
70
Plnon Electronics
51
Porta.Pak
96
Prultt Entervrlses
82
RMS ~ o r p o r a t l o n
Radlo Amateur Callbook
Reaencv Electronlcs
slep Electron!cs Co.
94
Southwest Techn~cal Products
95
90
Space Electronics Corp.
Spec~altv C o m m u n ~ c a t ~ o nSystems
s
78
Spectronics
89. 9 0
Spectrum Internattonal
84
A F Slahler Co
92
Swan Electronics
79. 8G
Systems Research. Inc.
41
Telrex Labs
74
73
Ten Tec
Topeka FM C o m m u n ~ c a t t o n s
78
Troplcal Hamboree
98
Trl L x Tower Corp.
1
Tufts Radio Electronics
94
VHF Englneerlng. Dtv. of BrownIan
104
Vanguard Labs
70
V~bratrol
99
Vlrglnla Polytechnic lnstltute
100
Vlsulex
86
Weber F l e c t r o n ~ c s
74
Webster Radlo
95
We~nschenker
92
Welrnu
90
G R. Whltehouse Co.
92
Wllson Electronics
58, 59
Worldrad~o
96
Cover II I
Yaesu Musen USA
Drake
RCS-4
I Remote Motor-Controlled I
Coax Antenna Switch
Control unit works on 110/220
VAC, 50/60 Hz, and supplies
necessary DC to motor.
Excellent for single coax feed to
multiband quads or arrays of
monobanders. The five positions
allow a single coax feed to three
beams and two dipoles, or other
similar combinations.
Control cable (not supplied)
same as for HAM-M rotator.
Selects antennas remotely,
grounds all unused antennas.
GND position grounds all antennas when leaving station.
"Rain-Hat" construction shields
motor and switches.
Motor: 24 VAC, 2 amp. Lubrication good to -40°F.
Switch RF Capability: Maximum
legal limit.
$120 suggested Amateur Net
See your Dealer. For details write:
R. I.. DRAKE COMPANY
540 Richard St., Miamisburg. Ohio 45342
Phone: (513)866-2421 Telex: 288.017
G R A N D O P E N I N G SPECIAL!
MOTOROLA METRUM I 1
5 0 (half suggested list! )
$249
Ack
.."..
ft
I.I. "I.
very conipetitive
prices on:
,.-
a .
CDE Rotors
.
-
Collins
Cushcraft
signal
tron
.L,
-
FEATURES=
rn
25 Watts out
Hot, selective receiver
rn
rn
I
12 channels
Single crystal R/T
PL provision built in
SPECIFICATIONS:
Transmitter Power: 1W/25W
Receiver Sensitivity: .2uV
Power Requirement: .3 A receive,
7.5 A transmit (25W)
Size: 23/4~ll~91h
inches
vood
sen
MO!;ley
Newtronics
Reaczncv
dorb
'an
I
Optional PL, AC power supply
and multiple repeater offset kits available
Mail orders shipped UPS same day on receipt of cashier's check or
money order. Mail orders add $ 7 0 for handling and shipping.
E
HOURS: 9:30 - 9 Mon. & Thun.; 9:30 - 5:30 Tues., Wed. & Fri.; 9 - 3 Sat.
O p e n more than 50 hours a w e e k t o serve you b e t t e r
ERICKSON COMMUNICATIONS, INC.
5935 North Milwaukee Ave., Chicago, IL 60646
We Service What We Sell
(312) 631-5181
More Details? CHECK-OFF Page 102
january 1976
103
Full over voltage and over current protection..1 1 1.
Now our best selling high current amateur power supplies are even better.
The PS-25C and PS-15C are well filtered and regulated power supplies.
Top quality components insure optimum reliability.
Look at these features:
Over-voltage protection crowbar.
Electrostatic shield for added transient surge
protection.
A foldback output limiter operates for loads
outside of the operating range.
Isolation from ground. The circuit is isolated
from the case and ground.
1151220 volt input - 50160 cycle.
Units are factory wired for 110 volt AC, 50160
cycle power. A simple jumper will reconfigure
the input for 220 volt AC, 50160 cycles.
Temperature range - operating: 0" to +5S0 C.
Black anodized aluminum finish.
PS-25C
SPECIFICATIONS
PS-15C
SPECIFICATIONS
Voltage Output:
adjustable between 12-14V
Load Regulation:
2% from no load to 10 amps
Current Output:
15 amps intermittent (50% duty cycle)
10 amps continuous
Ripple:
50 mV at 10 amps
Weight:
11-112 pounds
Size:
11-114" x 5-112" x 4-314"
Voltage Output:
adjustable between 10-15V
Load Regulation:
2% from no load to 20 amps
Current Output:
25 amps intermittent (50% duty cycle)
20 amps continuous
Ripple:
50 mV at 20 amps
Weight:
20-112 pounds
Size:
12-114" x 6-314" x 7-112"
K i t . . . . . . . . . . . . . . . . . . . $79.95
94.95
Wired and tested
K i t . . . . . . . . . . . . . . . . . . . $129.95
Wired and tested
149.95
..........
..........
ltem
I
part NO.
'
ORDER FORM
1
Price
Description
Extension
TERMS: c . o . D . . ~OI~check
with order. We alw accept
BankAmericard and Master
Chary.
CLAIMS: Nollfy VHF and thc
carrier of damage within
>even (7) days of receipt of
shipment.
RETURNS: Obtain authorinlion from VHF before returningony mrrchandiu.
PRICES AND SPECIFICATIONS: Subiect l o rhanw
without not~ce.
SHIPPING INFORMATION:
All %h$prnenls
are F.O.B. Bin*
h~mran. N.Y. 13902. Ship I
mints ;ill
be made by the
most convenient method.
Please include wR#ctmt funds
to cover hiDDlnI
. . and handllns.
Allow 3 lo 4 week% lor del~ver~.
I-
I
Total
Name
Address
S
Clty
a
l
Shipping
NYS Resident
e
sT u
Total
Sote
Master Charge or
BankAmer~cdrdNo.
zip
I
Expiration Date
january 1976
P
1
-;
D I V I S I O N O F BROWNIAN E L I C T K O N I C T CORP.
I
320 WATER ST.
P.O. BOX 1921
BINGHAMTON, N.Y. 13902
607.723-9574
I
1
-
Bank No.
104
Enclosed
I
1
I
I
(
.1
More Details?CHECK-OFF Page 102
YAESU FT-1O1E TRANSCEIVER
w
Now,more radio
radio company.
Are Yaesu's FT-101's the finest a l l around transceivers in the world?
Yes - and now the best is even
better. The new FT-101E includes
a potent R. F. speech processor. Plus
improved, easy-to-uselever switches.
A more refined clarifier control
for push-button, independent
clarifier operation. There's also a
160 meter crystal included without
extra charge.
And all the other features that
have made the FT-101 series of transceivers among the world's most
popular are s t i l l here: 260 watts SSB
PEP. Globe-circling power on CW
and AM. 160 to 10 meters range.
0.3uV receiving sensitivity. And
one very important feature you never
want to forget is the famous Yaesu
warranty, strong dealer network and
convenient serviceability.
If you're a serious amateur,
you're always looking for more radio.
And the FT-101E is just that. $749"
buys you a million bucks worth of
enjoyment. See your Yaesu dealer
or write for our catalog. Yaesu
Musen USA, lnc. 7625 E. Rosecrans,
No. 29, Paramount, Calif. 90723.
VAEBU
The radlom
*FT-lOIEE $e59.
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