Vertex Standard | VX-1210 | QST Green Radio Round-up APR2006

QST Green Radio Round-up APR2006
Green Radio Round-Up
Take a manpack radio out into the woods.
What your military radio lacks in bells
and whistles it makes up for in cool.
Philip A. Neidlinger, PE, KA4KOE
KG4KTW
T
he sheer breadth of things to do in Amateur Radio is amazing. As is to be expected, there are distinct subcultures
within Amateur Radio, each dedicated to a particular facet
of the hobby. One group, HFpackers, as they call themselves, is dedicated to the realm of portable communications. These
individuals take to the field with their radios in order to get some exercise and communicate with their like-minded brethren. HFpackers hike,
ride bicycles, canoe or simply set up their gear on picnic tables in a park
for an enjoyable afternoon in the great outdoors. An even smaller subset
of the HFpackers is comprised of those who enjoy operating military
manpack radios. They refer to themselves as “milpackers.”
I too have sampled from many of the sub-interests in the hobby. My
seven year old son, Jordan, has a keen interest in all things camouflage
and army. The devious inner workings of my mind began to churn…
“What could be more exciting than running around in the woods with
my son with a real green army radio?” I thought to myself. The idea
germinated, and I decided I needed to acquire a green radio for myself.
Further justification came in the guise of several record-breaking hurricanes smashing into the US coastline during 2004 and 2005. A couple
of those monster storms came uncomfortably close to our home on the
coast of Georgia. If we ever had to evacuate, we would need a portable,
self-contained HF radio that would be tough enough to survive immersion in water. If we had to evacuate, I wanted to remain connected.
True, I could have acquired a portable radio from one of the big
manufacturers, but the coolness factor was simply not there. Cool is
very important in this household. Every radio in my collection has a
pet name given to it by my two children.
dropped. Once you get past the supposed shortcomings and come to
grips with what these radios were designed to do, then the pure fun of
operating in the field will more than make up for the lack of features.
Finally, the talk power of most of these rigs is enhanced by very
aggressive speech processing. That 20 W radio signal will get through
under adverse band conditions with a reasonable antenna attached.
This is no surprise, since that’s what manpacks were designed to do.
Green Radios to Look For
Finding that green radio is going to be tough if you have to start
from scratch. Here are some rigs to look out for that become available
from time to time. This list is by no means complete, as I am sure there
are some radios that may be personal favorites to the reader. Most of
these radios can be heard in use on the HF pack frequencies.
PRC-47
This is a Vietnam era radio manufactured by Collins. Be advised,
however, that the radio only does USB, FSK and CW unmodified. The radio operates in the range of 2 through 12 MHz. It’s a
little heavy, however, to be characterized as a manpack. Be careful tuning it up into an antenna, as its vacuum tube finals are not
protected by any special circuitry. If you fry the finals, be advised
they are almost impossible to replace. The rig is rated at 100 W
maximum output and will operate from either 24 V dc or 115 V ac,
400 Hz. An internal antenna tuner will enable the rig to load up a 15
foot whip or wire antenna. A ’47 will occasionally come available on
eBay or in the various Amateur Radio classifieds. Fair Radio Sales
still had some PRC-47s the last time I checked.
HERB TATE, AA9GC
The Right Mindset
Acquiring a green military radio requires a certain mindset. In my
Collins PRC-47
opinion, you can’t go halfway and get whatever new do-it-all portable
“Swiss Army Knife Radio” the big manufacturers are offering. You
gotta get a real radio. A heavy radio…A milspec waterproof radio…A PRC-70
radio that will survive the storm surge when you won’t…A radio that
The PRC-70 was manufactured by Cincinnati Electronics
reminds you what it’s like to be mortal as your body aches as you trudge starting around 1964. The radio operates in the range of 2 to
down the forlorn path with it strapped to your middle-aged carcass.
76 MHz using USB, AM, FM and CW with a maximum power outBut, let’s be honest. If you are expecting a VFO knob, RIT, band- put of around 40 W, depending on the supply voltage. LSB can be
pass tuning or any other number of nice, convenient operating fea- implemented via a fairly simple modification. Supply voltages are
tures, then you will be disappointed. Typical power output is usually specified from 20 to 32 V dc. You must be careful that the supply
limited to about 20 W on average, with some units providing up to voltage does not drop below the minimum specified or the rig may be
50 W. Military radios are built for one thing and one thing only: provide damaged. The radio has an internal automatic antenna tuner that will
reliable tactical or regional communications under severe conditions in work with a variety of antennas. If you’re in good shape, you might
the field. Manpacks usually can be immersed in water or survive being be able to heft one of these babies onto your back. The PRC-70 was
Reprinted with permission; copyright ARRL
April 2006
57
FEDERICO BALDI, IZ1FID
MIKE FRYE, KM6AB
Cincinnati Electronics PRC-70
designed to bridge the gap between the frequency ranges covered by
the classic VHF PRC-25/77 and the HF capable PRC-47; in other
words, two radios in one box. I have seen a couple of these on eBay
in recent months for under $2000.
Harris PRC-138
JOHN COOK, K6ERO
PRC-132/M50B
Both versions of this
radio were manufactured
PRC-104
by Loral/Terracom with
Manufactured by Hughes and various other contractors in the Special Forces operations
mid 1970s to late 1980s, the PRC-104 is still in limited use by the in mind. The ’132 will
US military. Upon its acceptance by the US military, the ’104 and its survive immersion in deep
various accessories were referred to as the Improved High Frequency water up to 100 feet. The
Radio System (IHFR). This is a simple, no-nonsense radio. A friend radio will operate in the
of mine, K6ERO, swears by them. He claims one of his examples was frequency range of 1.6
dragged through the surf by US Navy Seals and still works as well as to 50 MHz from a 12 V
the day it came off the assembly line. Average power output is 20 to dc supply. The available
30 W. The radio runs on 24 V dc, and covers the frequency range of 2 modes are USB, LSB, CW,
to 30 MHz utilizing USB, LSB and CW. The PRC-104B version has AM and data. The radio is
a digital display. All examples of this radio have a very wide range designed to work with a
internal automatic antenna tuner that will handle a variety of antennas. base loaded “screwdriver”
The PRC-104 averages around $2000, depending on the version, and type manual antenna tuner
that bolts to the side of the
can be found on eBay from time to time.
unit.
It is a tough, unusual
BROOKE CLARK, N6GCE
looking radio. Used examples fetch from between
$2500 and $3500.
Loral/Terracom PRC-132
PRC-319
Hughes PRC-104
PRC-138
Perhaps the premiere green radio sought after by collectors is
the Harris PRC-138, which is currently in use today by the US
military, and is part of the Improved Special Operations Forces High
Frequency Manpack Radio System. It covers 1.6 to 60 MHz. RF
power output is selectable at 1, 5 or 20 W. The ’138 has a full DSP IF
chain with selectable IF bandwidth and DSP derived AGC. Transmit
audio is also digitized and processed via DSP. Some units have LPC10 digital voice built in as well as ALE (automatic link establishment),
which is becoming popular with hams. Built-in encryption is also an
option, but obviously amateurs cannot use this legally under Part 97
rules. This is a sophisticated, expensive radio occasionally available
on the used market. Working examples fetch in the neighborhood of
$2500 to $7500. Ouch! These little gems weigh in at 8.9 pounds.
58
April 2006
The PRC-319 is a late 1980s vintage rig manufactured by PhilipsMEL in England for use by their special forces. The radio is fairly
sophisticated with a built-in message keyboard for crypto and burst
modes, which are unusable due to amateur regulations. Frequency
range of operation is from 1.6 to 40 MHz, continuous, with a selectable power output of 5 or 50 W. Although the radio is not capable
of operation on LSB, this is another tough rig that can withstand
water immersion to
PAUL SIGNORELLI, WØRW
6 feet. By all accounts,
the receiver is fairly
sensitive. With a full
load of batteries the
’319 maxes out at 25
pounds. Expect to pay
a premium price for a
used ’319, as they are
difficult to find.
PRC-515, RU-20
The PRC-515 was
produced originally to
compete with the somewhat smaller PRC-104.
It was designed and
manufactured by
Collins Canada and
Philips-MEL PRC-319
FEDERICO BALDI, IZ1FID
later produced by Collins International. The design was also licensed
to Yugoslavia and other countries. The radio’s frequency range is 2.030 MHz, USB, LSB, AM and CW. Maximum power output is 20 W.
The ’515 requires 20-32 V dc to operate. The automatic antenna tuner
contains a motor driven
FEDERICO BALDI, IZ1FID
coil. The “WHIRRR”
you hear when you key
up on a new frequency
is dramatic. This is a
neat piece of radio kit
that is distinguished by
its extremely low current draw during
Philips-MEL PRC-2000
receive. Occasionally,
the Yugoslavian verantenna tuner is designed to work with a standard 10 foot whip and
sions of these radios
is not intended for use with random wire aerials. The transmit audio
will show up on eBay.
is very distinctive and has the classic military sound to it. Some may
They are easily distinfind the transmit audio objectionable as it is very punchy. Combat
guishable by the forRadio in the UK has these from time to time, but they are getting
eign words labeling all
increasingly hard to find. From all reports, it appears to be a reliable
the controls. Prices
radio. Prices range from $1800 to $2200.
range from $1000 to
$1600. Are you in good
TRA-931/Syncal 30
shape? That’s great:
Several versions of this radio were manufactured by Racal in
the radio with batteries
England
during the 1970s. A sizable number of these rigs on the
weighs in at around 22 PRC-515, RU-20
used market today were apparently seized during the fighting in Iraq
pounds.
and have found their way onto eBay and other outlets via a mechanism that remains largely unknown. The radio operates from 1.6 to
PRC-1099/1099a
JOZE HEBAR, S55E
The PRC-1099a is still being manufactured by Datron/Transworld.
Brand new, these radios (the “a” version) go for around $6000 from
the manufacturer...way too expensive for the average ham. As a very
good incentive, Datron still services these radios. Accessories such
as antennas, handsets, headsets and batteries designed for the PRC25/77 will work with
FEDERICO BALDI, IZ1FID
these radios, as they
utilize standard US
connectors. The radio
operates from 1.6 to
30 MHz with a maximum power output
of 20 W. The internal automatic antenna
tuner is fairly wide
range, but a series
connected outboard
Racal TRA-931
doorknob capacitor
is recommended for
30 MHz, AM, USB, LSB and CW with a selectable power output of 3
long random wires.
or 30 W. The internal antenna tuner is a manual type. You must turn a
The rig operates from
knob until an indicator light on the front panel goes out, indicating a
“ham friendly” 12 V
match. Working examples of the ’931 can be found on the used market
dc. These rigs are still
for less than $1000.
used extensively by
Third World nations Datron-Transworld PRC-1099/1099a
Vertex/Standard VX-1210
and by US personnel
I am including this radio in case the prospective milpacker wants a
at the South Pole McMurdo Station. Used examples can go from
between $1500 and $2500, depending on condition. My personal new rig with a 3 year warranty coupled with excellent performance. By
all accounts the ’1210, although black wrinkle finished and not green,
manpack is a ’1099.
performs well. The internal automatic antenna tuner is wide range and
PRC-2000
is reputed to be able to load up the proverbial “wet noodle.” Just throw
The PRC-2000 “Callpack” is another late 1980s rig manufac- a wire over a tree, string out a counterpoise, press the PTT, and you’re
tured by Philips-MEL. Examples of these rigs were used by British on the air. The radio operates over the spectrum of 1.6 to 30 MHz at
forces during the Falklands war. The radio is relatively simple to use, a power level of 5 or 25 W. The 500 memory channels are easily proand is approximately 25 pounds with the battery box full of D cell grammable. The biggest plus is that unlike its military cousins, the
NiMH batteries (13 total). The PRC-2000 will output 20 W high/ ’1210 only weighs 7 pounds with the 4 Ah lithium ion battery installed.
4 W low, USB, LSB, CW or digital modes. The internal automatic The VX-1210, with the usual accessories, retails for around $2000.
April 2006
59
WILLIAM TERRY, K4BYR
Vertex-Standard VX-1210
Operating Notes
Let’s be frank: If you plan to walk and talk at the same time with
one of these radios on your back, it helps to be in reasonably good
shape. Not many of us are accustomed to hiking with a 20 to 30 pound
pack. After a few weekends with a military manpack, however, you
will be in good shape. If you have your radio kit installed in a proper
pack, however, then the weight should not be too uncomfortable. I
use a British DPM camouflage pattern radio backpack obtained from
a surplus dealer on eBay.
The most commonly used antenna is the US military AT-271. This
is a 10 foot long, 7 part sectional whip with an internal spring and cord
that breaks down in seconds to a very small package. The ’271 is used
in conjunction with a rubber shock absorber that screws between the
antenna and the radio. Contacts can be made quite easily on the 20
meter and higher bands. However, things get difficult as the radiation
efficiency drops off as the operational frequency is lowered. If you
plan on using 40, 60 or 80 meters for instance, you may want to consider some sort of wire antenna that can be easily stowed. Contacts are
possible on the lower frequency bands, but they are more difficult to
come by when only using a 10 foot whip while running 20 W.
It is essential that some sort of dragging wire counterpoise be
provided — unless you like talking to yourself and feeling foolish. Remember: You’re using a short whip resonated by the internal antenna tuner in your manpack to the electrical equivalent of a
1
⁄4 wave radiator. Connecting an approximate 1⁄4 wavelength wire to
the grounding post of the rig will usually increase signal strengths
10 to 15 dB. These values have been determined empirically in the
field. Your mileage may vary. Due to interactions between the earth
and the wire, the lengths are somewhat shorter than one would expect.
Ground conductivity will also have an effect.
Again, these lengths are best determined empirically, but 10%
shorter is a good starting point. Use the formula L (in feet) = (234/freq
in MHz) × 0.9. It is also important to use an alligator clip or equivalent
as a safety disconnect in case the dragging wire gets hung up on
something or is simply stepped on. Teflon-insulated small-gauge
wire is a good choice,
KA4KOE
as it will not snag
as easily as other
types of wire. Finally,
the dragging counterpoise will impart
directivity to your
radiation pattern.
Here’s a helpful hint:
walk away from the
station you are communicating with. In
this manner, the
counterpoise will
be pointing at the
other station. Sounds
AT-271
60
April 2006
Internet Links of Interest
American Milspec — www.american-milspec.com
Army Radio Sales — www.armyradio.com
Army Radios Yahoo Group —
groups.yahoo.com/group/armyradios
Brooke Clarke’s PRC-68 site — www.prc68.com
Columbia Electronics —
www.columbiaelectronics.com
Combat Radio, UK — www.combatradio.org.uk
Fair Radio Sales — www.fairradio.com/backpa.htm
Helmut Singer Electronik — www.helmut-singer.de
HFpack — www.hfpack.com
John Cook, K6ERO — www.muttmotorpool.com/k6ero/
Milpack.html
Mil Pack Yahoo Group — groups.yahoo.com/group/milpack/
MilRadio — www.milradio.com/
Murphy’s Surplus — www.murphyjunk.bizland.com
Surplus Radios for Amateur Use —
www.co.missoula.mt.us/acs/radios/Radios.htm
Toronto Surplus and Scientific, Inc — www.torontosurplus.com
Mil Spec Radio Gear, by Mark Francis, KIØPF, has just been published
by CQ Communications, Inc — www.cq-amateur-radio.com
funny, doesn’t it? Well, it works wonders for improving signal
strengths on both ends of the path.
HFpack and Milpack operators congregate on a variety of frequencies. The most commonly used frequencies are 5.3715 MHz, 14.3425
MHz and 18.1575 MHz. Even if you don’t intend to acquire a green
radio, drop by for a visit. It’s always helpful to have a fixed station on
hand since some people seem to have trouble hearing the low powered
radios, as they aren’t 20 dB over S9 with 4 kHz wide audio bandwidths!
For additional frequencies and net times consult the HF Pack Web site.
Finally, you should at least be familiar with electronic troubleshooting to the component level. Many of these rigs are no longer being
manufactured, with the exception of the Harris PRC-138, Datron
PRC-1099/1099a and the Vertex-Standard VX-1210. At the very least,
it is a good idea to have a junker radio lying around for spare parts.
Given the nature of these over-engineered, tough-as-nails radios, however, reliability should not be an issue.
Conclusion
Operating a manpack radio in pedestrian mode is fun! My first contact with my manpack was with a Belgium station from my backyard on
17 meters. It is definitely addictive and can be likened to QRP operation
on steroids. The user, however, should always carry their license with
them if away from home. Given the current world terror situation, you
should refrain from operating a manpack near an airport or other sensitive installation unless you enjoy spending lots of time chatting with
not-so-friendly law enforcement types and possibly having your gear
confiscated. It should also be noted that exporting manpack radios is not
permissible under current US law. See the list of links in the accompanying sidebar if you decide to try and acquire a military manpack. The
Internet is a great place to start your search. Have fun and be safe!
Philip Neidlinger was licensed as KA4KOE in 1979 at the age of 16. He is
a registered Professional Engineer in the State of Georgia, where he has
practiced electrical engineering with DWG Inc, in Savannah since 1991.
He is married to Sheri Neidlinger, KG4KTW. They have two children,
Sarah and Jordan. The children’s name for Philip’s manpack is “green
bean.” He has written numerous articles for eHam, which include the long
running “Dead Electrical Dudes” series, currently airing monthly on the
bulletin service “This Week in Amateur Radio.” He has recently begun
studying and playing the theremin, a terribly difficult electronic instrument. You can reach the author at 103 Lazy Lagoon Way, Savannah, GA
31410; ka4koe@arrl.net.
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