Military Vehicles, November 1996,: Radio Equipment for M-38 Jeeps and other field vehicles

Radio Equipment for M-38 Jeeps and other field vehicles

Edward Greeley (
Sat, 16 Nov 1996 00:16:06 -0800


Several of you have asked very similar questions about the equipment I
have for sale. I hope this will give each of you the info you need.

Is the stuff I have correct for the M-38 application? In a word, yes.
That's the easy answer. The difficult part for you will be to figure
out what configuration of radio set you would like to put on your
vehicles. I'll try to give you a run-down on what I mean. My reference
for the info is an obsolete Army Technical Manual, TM 11-284 dated May

The items I have are modular components, i.e. complete
receiver-transmitters and complete power supplies which are used in
various combinations to form "Radio Sets". The largest configuation of
sets is the AN/GRC-3 through AN/GRC-8 series. The same modules were
also used in various smaller configurations such as AN/VRC-7 through
AN/VRC-10, AN/VRC-13 through AN/VRC-15, and a number of others.
According to the ref. TM, these sets were used in every imaginable field
vehicle of the era, including the M-38. This is all wide-band FM
equipment, by the way.

The RT-xx units I have cover three different frequency bands: RT-66, 20
- 27.9 MHz; RT-67, 27 - 38.9 MHz; RT-68, 38 - 54.9 MHz. The original
idea of having the three different bands, as I understand it, was that
one band would be for armor, one for arty., and one for infantry. You
will notice that there is 0.9 MHz overlap at the band ends so
communication between them is possible. I don't know which band was
supposed to be assigned to which type of organization.

The power supplies that I have provide all the operating voltages for
one RT-66/67/68. The PP-109 is for 12 volt vehicle battery power and the
PP-112 is for 24 volts.

In addition to the items I have, there are items used by the larger set
configurations which I do not have: Radio Receiver R-108/GRC,
R-109/GRC, and R-110/GRC. These are the "auxilliary receivers" which
cover the same frequency bands as their corresponding RT-66/67/68 units
and are used in the larger configurations of the GRC-3 through 8 series
sets. Also, there is a low-power receiver-transmitter, RT-70/GRC,
covering 47 - 54.9 MHz which, together with Amplifier AM-70/GRC, is used
on certain of the GRC-3 through 8 series. The AM-65 provides power for
the RT-70 as well as an interphone capability for the crew of large,
noisy armored vehicles, etc.

The modules comprising a complete set mount on a heavy shock mounting
base which also contains a junction box and most of the interconnecting
cables. The mounts you would be interested in are the MT-297/GRC which
is used for all configurations of the GRC-3 through 8, or the MT-299/GRC
which mounts one RT-66/67/68 and one PP-109/112 for the VRC-xx series.

There are numerous other small accessories used with these sets: small
weather resistant loudspeakers, microphones, head and chest sets,
telephone type handsets, antenna bases and mast sections, canvas covers
for the radio sets, etc.

Caveat emptor! As I said in my earlier E-mail, I have NOT checked the
items for sale. They are the left-overs from a couple of lots of stuff I
successfully bid on at DRMO to get some items I needed for my little
collection. (I'm into this kind of stuff, not vehicles.) I don't have
the time or ambition to test and, if necessary, repair this stuff. All
I guarantee is that each item is "as-received" from DRMO, is complete
and in standard govt. configuration. My firm prices for the items are:

RT-66 or 67 or 68 $40.00
PP-109 (12 volt) 25.00
PP-112 (24 volt) 15.00
MT-297 20.00
MT-299 15.00
AB-15 (antenna base with mounting bracket
but NO antenna mast sections) 10.00
H-33 (telephone type handset) 10.00
M-29 (microphone) 10.00

Packing and shipping for all items is extra.

Some items I have several of, some only one or two - "first come, first

You can also find these items, plus many of the modules and accessories
I do not have, at Fair Radio Sales, 1016 E. Eureka St., Lima, OH 45802,
(419) 223-2196. They also have reproduced manuals for the stuff. They
have an annual catalog which contains all sorts of old military
electronics. Check them out! You will find that the prices on the stuff
I do have is cheaper than theirs!

Sean inquired whether this equipment would mount on an MT-1024: I doubt
it very much. That designation is much too high a number for this old
series of equipment, to the best of my knowledge.

Jim inquired as to what would be appropriate for a 45 ID MP jeep. I
don't have the foggiest, sorry to say. I do have my own idea on the
subject but no authoritative info. The equipment discussed above is
operator tunable. It also operates in the (then) tactical frequency
bands. I doubt that such equipment would be used on an MP vehicle in a
garrison situation stateside. In that situation, I would imagine that a
fixed frequency set in the VHF band (around 150 - 170 MHz) would have
been used. An example of such a set would be an AN/VRC-19, if I
remember correctly. Conversely, the above equipment may very well have
been used on MP vehicles OS. Probably a simple configuration such as
one of the VRC-xx sets with one RT-66/67/68 and the appropriate power
supply, depending on the vehicle's battery voltage.

If anyone has need of more specific info, shoot me a line at my E-mail
address and I'll try to answer as well as I can.

Thanks for your interest.

Ed Greeley