Ham Radio Magazine 1987

112 Pages·2006·17.31 MB·English

OCTOBER 1987 1 $2.50
magazine
Six Bands in One Mobile!
ICOM IC-900 Interface Unit A is in-
stalled in a location near
FIBER OPTIC
the driver's seat.
FM MOBlLE
7
ICOM introduces the
revolutionary IC-900 multi- and can
band FM mobile trans- be installed
rill
ceiver. ICOM, first in
utilizin~fi ber
optic tech- A R ber
nology in - optic cable
1
amateur rins from
radio. en- - lnterface A
ables v,o-u - \-- to lnterface
\
to create your own \ 3€, which
mobile communications transports
svstem. Six band combi- n~ls/lnlertaceU nll I3 abun-
,,
advanced, versatile. com- ""ll
Band Units are
Remote "stacked" onto the Inter-
Controller. face B Unit via the sup-
Features Galore. The eacn w Measuring only 2 plied mounting bracket.
memory and program-
IC-900 is an operator's inches high by 5.7 Optional band units avail-
mableb and scan, and
dream ...L isten on two inches wide by 1 inch deep, able are:
bands simultaneously or subaudible in actualt he remote controller can
transmit on one band and HZ readout. be installed on your car's u",? g%% Fnqusncy
receive on a different band The IC-900 includes an dash or sun visor with the UX-191 IOW,IW 28.30~~1
when using a second ultra compact remote con- supplied velcro. And, if UX-291 Z~WISW 138-174~~RI:1
speaker ltrue full duplex troller, an lnterface A unit, you want, take the controller 140.1-ISOMHI TI
IJX-2s" 4 5 ~ 1 513~8 .174~R~I; ~
crossband operationl. 10 Interface B unit. SP-8 with you when you leave 140.1-ISOMHZ Tx
memories pei band, inde- speaker, HM-14 up/down your car. The controller fea- zux:-:,A: : ,SW,SW 22,260,3-6~MZHS~M HZRT xr :
pendent PL tones and DTMF mic, fiber optic and tures a super large, highly t:t;:c
4 ~ ~ : ~ ~ ~ z
-
NOW A U K ANTRONICS KPCs and KAM
ARE TCP/IP NETWORKING COMPATIBLE
INCLUDE THE PACKET MAILBOX
AND COME WITH 32K RAM
-
EXTRA FEATURES
NO EXTRA CHARGE
That's right! Now all Kantronics packet units* include the
Personal Packet Mailbox", come with 32K RAM, and are TCP/IP
Networking con
there's more . . .
-
KAM and KPC owners" you can add the Packet Mailbox
and TCP/IP coml
At Kantronics
- 1
Check below and see we offer more features and the best
customer support around.
w z T M
This low costlhigh performance Kantronics
TNC features a built-in HF/VHF modem, the Personal Packet
Mailbox. full dUE
bility. The serial R
computers. even Commodores. KPC-2 is TCP
compotible, includes 32K RAM, and u
indicatorsforea!
fully compotible
(<AMTM 1
KAM is the fully programmable All Mode unit
that lets you operoteVHF Packet, HF ~acket.CW/RTP//l
and AMTOR. But that's not all . . . I
Only KAM's dual VHF/HF radio ports work together for
simultaneous Connects, Digipeating, and VHF/HFGATEWAY
operations. And now KAM is TCP/IP Networking compotible,
I
comes with 32K RAM, and has the Personal Packet Mailbox
ALL STANDARD.
KAM include
RS2321llL serial
1
HF operation. KAM even comes with an external modem
connection point for optional 2400 b/s packe
For the greatest degree of sensitivity and flexit
KAM, Kantronics All Mode. 1
KPC-4lM
Only KPC-4 features simultaneous
Connects, Digi~
fully functional \
a watchdog timer. What's more -you can add 2400 b/s
1
operation to F
Modem".
--
KPCd includes the Personal Packet ailb box and 32K
RAM (expandable to 64K), and is TCP/IP Networking
. 1202 E. 23 St Lawrence, Kansas 66046 [phone] # 111
KAM. KPC-2. KFCd and KFC-2403 units hi 741-87 rx l0tw
" KFC-1 (Rnket C&rnunicotor). KFC-2. KF&?FC-?dm
First Again!
Non-volatile operating system.
t
Even after memory back up cell dies.
2 rn, 75 cm CP* Dua' 'ander all operating features remain intact!
No re-programming or "board-
A Kenwood original just got better!
swapp~ng"n ecessary!
Kenwood was the first to develop a
Programmable band scan and
2 m/70 cm mobile radio in a single, I
memory scan with memory chan-
compact package. Since then,
nel lock-out.
other companies have imitated the
I Large. illuminated LCD display
concept, but still have not done it I
and main knob. For excellent vlsibil-
the "Kenwood way:' The all-new I ' ' I !'J r ity in direct sunlight or darkness.
TW-4100A is more compact, more 1.9 /" H x i'ki,'" U ;lnd wc:t(]lls less
Selectable frequency step for
powerful, and packed with more than 4 pounds!
quick and easy QSY.
features than ever before! With Proven high performance
Voice synthesizer VS-2 option.
many new features and accesso- Kenwood GnAs FET front end
ries, and backed by Kenwood's receiver. Optional accessories:
experience, the all-new Kenwood Easy to operate! Only 3 knobs and PS-50,PS-430 DC power suppl~es
Dual Bander is light years ahead 8 keys on the front panel. MU-1 DCL modem unlt TU-7 CTCSS en-
of the rest! separate antenna portsf or VHF co~lcr VS-2 Vo~ces ynlheslzer SW- 1008
S:~al.-c' ,'>lef ull duplex cross band and UHF. Minimizes loss and SWH/Pow~?r/Vomlt eter 140-450 MHI for
motvle use SW-200B SWRIPower meter
("~!epl,ones tyle") operation. increases and performance!
tor bosr statlor, - 140 450 MHz, 0 200 W
Remote base or cross band repeater 10 memory channels. Llthium battery 2 ranges. SW-~ISW-~ 2 70 cm
funct~onp ossible (a control operator backs up memory. Store frequency. antenna tuner SP-40 Compact s-p eaker
offset, subtone. Two channels store SP-SOB Moblli! spf:;rker PG-2N Extra
the transmit and receive frequencies , DC cahlt! PG-3B DC nolse llller MC-60A,
;. \v;.'ts on 2 m. 35 watts o independently for odd split or MC-80, MC-85 ltase stallon mlcs. MC-55
cross band operation. (8-pin) Mt.~l>~nlilec rophone MA- 4000 Dual
<#Hz Frort p;.:,ral-< nr , ,le CTCSS band moblle antenna w~th
duplexer (shown)"
I .: . '*'? on~r;\!~or,!- ,nc ~rtat.' tone (when on+!o--11i U-7 is MB-ll Extra rnob~lem ount
5r?'?; anc' CAP frequencies) and installed.)
A~:p-A49.995M Hz.
-=-w
KENWOOD U.S.A. CORPORATION
".',t,. M~,,O,m,. o, t,m,.,'k~I ? In<o(r ,~ ,e,~r,ilw,,!o,,!o,,ds,,u ,,pm"l!er,,,d. l ,<b,,f,.., i,,',:: , 2P2O0 1B Lo xD 7o2n7i~4n5g. LuoenzSg t B,L eoancgh B. CeAac 9h0. 8C0A1 9-50 811405
,,, ,c ,,~#,,!,f,,',,l,,><Pr>, ?,,,, ~,,,,1"0 , ,Pi>"dlt-r 0,,"r,71,"~7
iirr~Itc.:i~onarr ~dor,cvru blecr ru clwnge w,ltiour noltce or obl!garron
omp pi^!.* I~~YIC,~C! arwalr are ava,lirble lor ail Kenwood rranscelvers and mola ccessorlec
magazine
contents
8 low-cost pc board layout software
Eva Freeman
17 antenna relay sequencing
Mark Mandelkern, KN5S
27 VHFIUHF world:
impedance-matching techniques
Joe Reisert, WlJ R
41 return of the 360-degree
propagation prediction
Henry Elwell, N4UH
57 practically speaking:
troubleshooting dc power supplies
with an oscilloscope
Joe Carr, K41PV
65 pulse width modulated
dc-to-dc converters
William R. Hennigan, W3CZ
79 ham radio techniques:
white noise revisited
Bill Orr, W6SAI
89 locator field list
Folke Rosevall, SM5AGM
Canadd
100 Elmer's notebook:
All packet radio
Tom McMullen, WlSL
intern.
106 advertisers index 98 ham mart
and reader service 91 new produc
6 comments 4 reflections
85 DX forecaster 97 short circui
96 flea market
October 1987 010 3
REFLECTIONS
the possessed
During the anything-goes sixties, while attending City College, I shared an apartment with two roommates on the
upper west side of Manhattan. This editorial is dedicated to one of them. Without naming names (let's just call him
"Mr. A"), this roommate was the antithesis of what most of us Radio Amateurs have become.
We're like magnets. Anything we see that might be remotely useful, even in the far-distant future, will come to
us to be saved for that eventuality. Now, I'm not talking about just nuts and bolts. I'm talking real quantity and diversity.
Look around your shack, which in some cases might be considered the entire house. If you're like me, you've prob-
ably spread out all over.
What was that sound? The one just before that awful grinding noise and the smell of burning motor? Was it that
1-percent precision, 141. 7-ohm resistor you've been looking for since Labor Day - the part you needed to finish your
super-deluxe noise bridge - being sucked up into the vacuum cleaner? Well. it's history now. The vacuum cleaner
has claimed another victim.
"Just a darn minute!" you exclaim. "That resistor was carefully placed on the dining room table!"
Come on. Follow me. Starting from the shack, let's take a quick walk - in our mind's eye - around the house.
It's probably impossible, even dangerous, to walk around any other way because of the overcrowding or perhaps be-
cause of those three 6-foot racks of tube equipment you've built over the years. All those dangling jumper cables
(control, audio, digital, and rf) seem to want to reach out and trip people. Come on, don't let me hear that argument
you give your spouse about how keeping all that equipment going helps keep the house warm, thereby cutting the
the fuel bill, and hasn't she noticed how nice and dry it is down in the basement when all those pretty tubes are lit?
I've heard all those justifications before. In fact, I've used some of them myself.
As painful as it may be, let's leave the shack and move on. No point stopping at the kitchen or dining room tables;
we all know what we'll find there.
If you're at all like me, you have many different interests and probably subscribe to a number of magazines that
address those interests. Are the magazines all neatly stacked on a bookshelf in the radio room - just as pictured in
any of the operating manuals that show what the typical ham station looks like? Naah. Who are you kidding? Those
magazlnes are strewn all over the place - scattered atop the TV and on side tables and even chairs, heaped in piles
in corners, in the attic, in the hallway, the bathroom, the garage, and, of course, on the floor. Did you ever consider
the possibility that your spouse might consider this an encroachment on her living space?
Speaking of the garage, that's a story in itself. It's amazing to consider how seven sections of Rohn 45 can fit in
there so nicely. But the XYL's car? Well, that's a different matter. Maybe winter won't be so bad after all.
I won't even mention those drums of surplus wire, cable, or whatnot that you picked up at that flea market in 1979.
What a deal! Heck, you're going to help her shovel the snow off the car this winter anyway, right?
Moving outside, did you know that the great outdoors offers almost unlimited storage capability? Of course you
do. Why, there's the evidence: more rusting tower sections, some sturdy anchors, a hundred feet of guy line, and
a 6-foot dish! Too good to sell, give away, or discard, they're also too big for the garage. But they're not too big
for the great outdoors!
"All right!," you protest. "Maybe there's some truth to what you've been saying. But what's the point?"
This is it: perhaps October's the time to take another look at what we possess, or more appropriately, what possess-
es us. Maybe this is the time to go through the entire house, gather all our treasures together, and decide what's
really important, what we really want to keep. Let's sell the rest, or better yet, donate it to a worthy cause like that
Novice down the block. After all, we've gotta start 'em right on this acquisition madness, don't we?
I hope you appreciate the gravity of the chance I'm taking by writing this editorial. If my XYL ever reads this, I
might have to practice what I preach. As a friend of mine is wont to say: "End of message."
And what about the legendary Mr. A, to whom this editorial is dedicated? Well, Mr. A owned exactly two shirts
and two pairs of shoes, pants, and socks - and barely anything else. When the time came to move, I had to rent
a trailer to cart my possessions. Mr. A put everything he owned into his attache case and walked away.
Rich Rosen, K2RR
Editor-in-Chief
4 October 1987

Vance and his crew of key engineers was subsequently translated into two
at the RCA Camden plant frequently. scratches on a platinum bar kept at 23
He was a fine gentleman, with excep- degreees C. (Now that we deal in
mments
tional electrorlics savvy and manage- subatomic distances, this is gross
'I ment know-how. I regret I didn't get measurement indeed. Thus the scien-
I
a chance to meet George Brown, who, tists have defined the meter as the
I believe, was at RCA Labs (elsewhere) distance that light will travel in
at the time. 11299,792,458 second!
In hindsight, my offset drooper ar- Obviously, you won't have to throw
ticle could have been more accurately away your tape measure when you put
ground plane antennas
titled "An Improved Drooping Ground up that new beam!
Dear HR: Plane. " For over three decades, droop- Josef Darmento, W4SXK
I was rather taken aback at a recent ing radials have been widely used by Merritt Island, Florida 32952
ham club meeting when a couple of the ham fraternity to permit direct con-
friends informed me that according to nection of 50-ohm coax. However, this bird chaser
a letter to the editor in ham radio, aggravates antenna effect. The Offset
Dear HR:
my "offset drooper" ("The Offset Drooper configuration provides a sub-
Noticed the letter from Bernard
Drooper: An Improved Ground Plane," stantial reduction in antenna effect
Kirschner in the May issue ("Corn-
January, 1986, page 431, had been in- without adding a detuning sleeve or an
ments," page 6).
vented years ago by a Frenchman. extra set of radials, while still maintain-
He's having troubles using an owl as
DJOTRIOE8AK's letter in the June, ing a 50-ohm match.
a bird chaser, is he? Perhaps he should
1987 issue, in which he discusses the Woody Smith, W6BCX
use one of those inflatable snakes from
origins of the venerable ground plane Anaheim, California 92804
the local garden shop instead. Tie one
antenna, states, immediately following
end of it about halfway out along the
his reference to my article, "This
is nothing sacred? boom and the other end on the pole
VHFIUHF antenna was invented sev-
eral years before in France . . . . ,r Dear HR: so it looks like it's just climbing onto
the boom. Those things would scare
A careful reading of the letter, how- With this rather untimely heading
me off - as well as all manner of
ever, makes it quite clear from the con- ["Is Nothing Sacred?" - Ed.], The
feathered creatures.
text that the statement "This VHFI New York Times recently reported
Charles Chrestien
UHF antenna was invented several slight changes in more than 100 of
Sunnyvale, California 94086
years before . . ." applies to the earlier the fundamental constants used in
mentioned classic ground plane credit- science. These changes represent a
neighborly gesture
ed to Dr. George Brown. But appar- consensus of scientific opinion by the
ently, if one hurriedly skims the letter, world's leading measurements labora- Dear HR:
the remark can be mistakenly applied tories, including those in the Soviet There's a very useful technique for
to the "offset drooper" version of the bloc and our National Bureau of Stan- dealing with neighbors who complain
ground plane antenna. dards as well. of TVI. Instead of making critical com-
While on the subject of originality, It is gratifying to learn that the speed ments about their television receivers,
I'm surprised that the matter of French of light hasn't changed, and remains try lending them a table model color
prior art pertaining to ground plane at 299,792,458 meters per second. I receiver fitted with the proper filters.
type antennas has taken 50 years to shall leave it to some computer whiz Then ask them to help you perform a
surface. I do know that I certainly am to translate that into feet and inches; simple test.
not in a position to pass judgement as my hand calculator is inadequate. Three or four days later they'll ask
to worldwide prior art. My information However, whereas this number was you to tell them how they can fix their
was taken from the article, "The previously termed "approximate," it is receivers. Amazingly, even the most
Ground Plane Antenna: Its History and now defined as "exact," and the sec- formerly rabid neighbor will approach
Development," by Harold Vance, Sr., ond is considered constant. The meter you in a very friendly and reasonable
W2FF (now deceased), which ap- is then defined in terms of the vel- frame of mind.
peared in the January, 1977 issue of city of light and the second - a nice As proof of the effectiveness of this
ham radio. Catch-22! Greater accuracy will be method, how many Amateurs do you
George Brown and Harold Vance achieved with future improvements in know who have ground radial systems
were both highly respected VIPs at measurement. covering not only their yards, but a
RCA during World War II. As section The meter, as originally proposed by side neighbor's yard and the yard of
head and project officer on some new a French vicar in 1670, was defined as the neighbor in the back as well?
USMC elec.tronic equipment under de- 1 ten-millionth of the distance between John Labaj, W2YW
velopment, I used to visit Harold the equator and the North Pole. It Elsmere, New York 12054
6 October 1987
New MFJ-1274 lets you work VHF and HF packet
. . .
with built-in tuning indicator for $169.95
. . .
you get MFJ's latest clone of TAPR's TNC-2. TAPR's VHFIHF modem and
built-in tuning indicator that features- 20 LEDs for easy precise tuning
Now you can join the exciting world of machine specific TNC or one without hardware
packet radio on both VHF and HF bands with a HDLC as higher speeds come into widespread use.
. .
precision tuning indicator. for an incredible You can also use the MFJ-1274 or MFJ-1270 as
$169.951 an excellent but inexpensive digipeater to llnk other
You get MFJ's top quality clone of the highly packet stations.
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made TAPR's modem selectable for both VHF.and hardware HDLC for full duplex. true Data Carrier
HF operation, added their precision 20 segmcnt LED Drtect for HF. multiple connects. 256K EPROM. 16K
tuning indicator, a TTL serial port. an easily RAM (expandable to 32K with optional EPROM).
replaceable lithium battery for memory back-up and simplr operation. socketed ICs plus much more.
put it all in a new cabinet.
You get an easy-to-read manual, a cable to
If you don't need the tuning indicator or the connect your transceiver (you have to add a
convenience of a switchable VHFIHF modem, choose connector for your particular radio). a connector for
the affordable MFJ-1270 for $139.95. the TTL serial port and a power supply for 1 10 VAC
All you need to operate packet radio is a operation (you can use 12 VDC for portable, remote
MFJ-1274 or MFJ-1270. your rig. and any home or mobile operation).
computer with a RS-232 serial port and terminal Help make history! Join the packrt radio
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. . Now you can tune in
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This MFJ clonc 01- the TAPR
Unlike machine specific TNCs you never have to
MF.J. 1273. 549.95 tuning indicator makes
worry about your MFJ- 1274 or MFJ- 1270 becoming
tun111gn atural and easy - - it shows you which
obsolete because you change computers or because
dirrc.tion to tune. All you have to do is to center a
packet radio standards change. You can use any
single LED and you're precisely tuned in to within
computer with an RS-232 serial port with an
10 Hz. 20 LEDs give high resolution and wide
apropriate terminal program. If packet radio
frequency coverage.
standards change, software updates will be made
available as TAPR releases them.
Thr MFJ-1273 tuning indicator plugs into the
Also speeds in excess of 56K bauds are possiblc MFJ- 1270 and all TNC- 1s , TNC-2s and clones that
with a suitable external modem! Try that with a have the TAPR tuning indicator connector.
MA
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Reader Service CHECK-OFF Page 106 r/ 112 October 1987 7
low-cost pc board layout software
The price has dropped tion key overlay, a sample pc board, and a 30-day
money-back guarantee.
but watch out Procad xtra", from Interactive CAD Systems, fea-
-
tures filled areas for ground planes and lets you se-
lect up to seven fill patterns and styles of lines.
for those options!
1 Complex symbols such as standard power-supply lay-
1 outs or memory bus structures can be stored in the
I program's library for repeated use. Procad xtra costs
1 $695; it runs on IBM PCs and on Digital Equipment
Corporation's VAX minicomputers.
The price of sophisticated printed circuit board , Similar features are found in QTech's Qwik TeP
layout packages has plummeted. For less than $1000 package. That's not too surprising - they were de-
- often much less - you can buy an easy-to-use veloped by the same programmers. Like Procad xtra,
package that can handle almost any board layout. Qwik Tek runs on IBM PCs and on DEC VAXs; the
Even if you've never used computer-aided design I base price of Qwik Tek is $695.
(CAD), you can master any of these packages quickly.
automatic layout software
Until recently, pc board designers had to choose be-
tween sending their designs to pc board service bu- Qwik Tek and Procad xtra aren't alike in all respects.
reaus or using expensive layout packages that ran on Procad xtra is a purely interactive system, which is all
dedicated work. stations. CAD packages priced at less you'll need for most analog applications. But for de-
than $1000 were drafting tools at best. But all that's signs with large numbers of components, you'd need
changed; today's relatively low-cost pc board layout a program that could position them on a layout and
software packages provide almost the same features draw interconnections among them. A $7900 version
as work station-based systems. What's more, they run of Qwik Tek includes these capabilities, offering a
on personal computers, which means they're now schematic editor, interactive layout, automatic place-
within reach of clubs and individual Amateurs. ment, and an autorouter.
All packages aren't equally suited for all applications, An autorouter interconnects the components on a
however. For analog designs, a package should pro- layout automatically. The sophistication of the auto-
vide an area-fill capability, which you'll need for con- routers in low-cost pc board layout packages ap-
structing irregularly shaped ground planes. Some proaches that of autorouters in the most advanced
packages are tailored for digital designs and conse- work stations and mainframe-based layout systems.
quently don't provide a way to create copper planes Yet the price of an IBM PC-based autorouter can be
of arbitrary shape. relatively low. For $750, CAD Software's Pads-Route@)
Most of the low-cost packages, however, offer tools autorouter provides three routers: power-and-ground,
for filling in copper areas. For example, area fill is a memory, and maze. The power-and-ground and mem-
standard feature of Accel Technologies' Tango-PCB@ ory routers specialize in power supply and RAM in-
program for IBM PCs and compatible personal com- terconnections; the maze router interconnects all other
puters. Together with the package's I-mil grid, the digital and analog components.
area-fill command enables you to create copper areas
and thick tracks for microstrips and ground planes. Its By Eva Freeman, 108 Trapelo Road, Lincoln,
$495 price includes software, documentation, a func- Massachusetts 01773
8 October 1987