Which Radio(s) for M37?

[w30bob]

H( Guys,

Full disclosure.....I know nothing about military radios. Knowing that, can you tell me what model number radios were used in the M37 during the Korean War? I tried looking on the web but it's a bit confusing. I'd like to start looking for a radio now, although my trucks are a long way from being done. But if I know what to look for I've got some time to find the bargains. Also, if the radio needed a power supply or a speaker or such can you tell me those model numbers are too. You don't have to post pics unless you're in the mood....just the models and I can Google them to see what they look like. Thanks in advance.

regards,
bob

[52 M-42]

I think I have most of the tactical radios from the Korean and early Viet Nam period. The ones I have are the "Old Family Radio Systems".

They are the A/N GRC-3, -5 and -7. There are lots and lots of variations but those 3 cover Infantry, Armor and Artillery. I also have the A/N GRR-5 receiver.

I have a lot of the manuals and a list of websites that cover these radios. There are a lot of combinations. The three above are the big sets with the rebroadcast ability and remote operation capability.

I've got pictures too if you're interested.

Please let me know if I can be of help.

52 M-42

[w30bob]

Hi 52,

Thanks for the info! I did a little digging around last night looking for those three sets........and I have to admit I'm totally blown away but what was involved with radio communication back in the day. Truthfully, I'm overwhelmed by what's involved, as I was thinking a "radio" was just a single box that mounted in the bed of the M37. What I saw was that a "radio" was boxes and boxes stacked on top of each other, connected by a myriad of cables. Multiplexers, power supplies, transmitters, receivers, low power, high power..........it was enough to make my head spin. In light of this recent discovery.....I'm thinking I may change my plan to put a vintage radio in my M37 someday. I just don't have the brainpower available to figure it all out. I'm thinking just mounting the antenna on the side of the truck might have to be good enough.

But the radio thing sure looks like an interesting hobby for those so inclined. A whole hobby unto itself. Thanks again for the info..........turned out to be fascinating stuff, and I have a newfound appreciation for military communications back in the day.

regards,
bob

[vtdeucedriver]

Bob. Give me a bit and I will post pics of my recent radio install.

[52 M-42]

Don't be intimidated by all the different radios. You can fill the back of that truck with radios if you want to, or just have one or two.

Decide what you want the truck to be (platoon level, company level, battalion or division level) and it will sort itself out as far as radios go.

It is just like restoring the truck; pick up a piece here and there and slowly put it together. vtdeucedriver did a great install on his truck which is truly representative of how it was probably done (a lot) in the field.

So once again if you need help or are interested, just ask; there are a lot of people here who can help you. Steel Soldiers has a whole subforum devoted to just radios with a bunch of very knowledgeable people.

Good Luck and don't be scared off by the apparent complexity. You can make it as simple or complex as you want. You decide.

52 M-42

[Cal_Gary]

If you just need commo you might consider an AN-PRC77 pack radio: 'Nam era, fits on the floorboard or seat, easily secured or moved about. Use the antenna wire to your outside antenna or the flex antenna that attaches to the top mount.
Gary

[k8icu]

You have many option Grasshopper. The GRC series tubed radios are correct for 1950s and early 1960s. The VRC transistor (ish) radios such as the PRC 25/77 radios with mobile mount or the RT-524/VRC is 1960 -1980s (early 1990s) is also correct if doing a vehicle during the Cold War/Vietnam.

It all depends on what period you want to display your truck as and how much money you have to spend on equipment.

[vtdeucedriver]

http://i33.photobucket.com/albums/d86/n ... e39390.jpg
http://i33.photobucket.com/albums/d86/n ... e39390.jpg
This is a Korean War RT-66 with a PP-112 powersupply and I would need to get you the MT number for the mounting tray. On the M-37, the radios in the back were mounted on a troop seat with a reinforcing kit. My M-37 is a 1951 that at one time had the spare relocated to the door. Since the holes already existed and still had the mount installed. I put the radios on a "Field Mod" tray that I came up with like I would have done in 51 and installed them in the back. This way I can still put up the troop seats.

[w30bob]

Hi VT,

Well that doesn't look too bad....maybe I was over-reacting a bit. So did they mount the radio on the driver's side troop seat up near the cab? That would place it near the antenna mount I see on the driver's side most of the time.....or did they mount it on the little swing down troop seat against the bed on the passenger side? I assume there it would be closer to the batteries in the cab for power.

Two silly questions......I was reading that radios were sometimes powered by 24V "vibrators". What exactly is a "vibrator"? Keep it clean guys....I'm talking w/respect to radios. Second question.....I assume these radios are waterproof.....meaning they can be exposed to the elements?? Or was that a no-no?

thanks,
bob

[397thBG]

The vibrator converts low voltage DC to high voltage AC. It contains a coil and contacts that are similar to ignition points. Radio sets need several different voltages to operate, which are all supplied from the 24 volt power supply. Some operating voltages for the RT6* series radios are over 400 volts. The vibrators are the Achilles heal for these old sets and get "stuck". When that happens you don't get the high voltages needed to operate.

The radios were originally waterproof, but with 60+ year seals you are taking a risk.

[w30bob]

Thanks 397th!

bob

[k8icu]

That is why I also mentioned the Vietnam era radios with the RT-524 or the PRC 25/77 mounted. You don't have th vibrator supply to produce the differnet voltages needed for the tubes in the RT-68 radio. You just need the trucks original 24V to run them since they are all solid state equipement. Yes the radios where sealed and fungiside (Not sure of the correct spelling of the word) but it was a paint or laquere that was sprayed onto the chasy and electrical componits to keep the boards from getting fungus and mold etc from growing in them. As was stated 60+ year old radios may fail at the seals.