Prc 77

Want to put radios in your jeep? Discuss it here.

Moderators: rickf, raymond, Mr. Recovery

Husker
Master Sergeant
Master Sergeant
Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Prc 77

Unread post by Husker » November 28th, 2016, 1:38 pm

Today I'm picking up a pair of complete PRC 77 radios that function. From what I can tell I will need a VrC64 to mount on my mutt once it's done. Do I need another amplifier to go with it as I have seen some mobile amps going with the 77 in back pack or vehicle configuration. Also does anyone know if this will talk to modern military radios when they are on single channel plain text or are they a completely different freq
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

Husker
Master Sergeant
Master Sergeant
Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Prc 77

Unread post by Husker » November 28th, 2016, 9:59 pm

Well the radios I got turn on and blast static but won't talk to each other........... anyone know how to trouble shoot them? I can mostly only used modern army radios
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

199th mp
Major
Major
Posts: 1157
Joined: January 18th, 2010, 2:59 pm

Re: Prc 77

Unread post by 199th mp » November 28th, 2016, 11:20 pm

look for kurt lesser, either here or over on the G503 page. he's very knowledgable when it comes to radio gear. he got me a working 524 for my jeep. have you made sure both radios are on the same frequency, and on low power? have you moved them out from each other at least 100 yards? set both of them on new squelch, off. do both handsets work? also, they will not commo with new radio gear at all. completely different.

User avatar
rickf
General
General
Posts: 19741
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Prc 77

Unread post by rickf » November 29th, 2016, 10:36 am

If you do somehow manage to get on a modern military channel it would turn out very bad for you!!!!!!!
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Husker
Master Sergeant
Master Sergeant
Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Prc 77

Unread post by Husker » November 29th, 2016, 2:17 pm

Thanks for the help I'll try it out when I get home

I will test the handsets they both seem to function as they draw static but I don't know how to go to low power mode on the 77
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

User avatar
rickf
General
General
Posts: 19741
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Prc 77

Unread post by rickf » November 29th, 2016, 3:43 pm

This may sound like a dumb question but I have seen people not do it, and fry their radios. You do have the antenna on both units right?
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Husker
Master Sergeant
Master Sergeant
Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Prc 77

Unread post by Husker » November 29th, 2016, 3:46 pm

I do. I have the flexible spring section and the metal tape whips on both
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

kmam
Sergeant Major
Sergeant Major
Posts: 524
Joined: June 6th, 2015, 7:39 am
Location: Kuranda, Far North Queensland, Australia

Re: Prc 77

Unread post by kmam » November 29th, 2016, 4:47 pm

First let's confirm where you are at:

1. Both set are fully assembled, i.e. Good battery, antenna and handset connected.

2. Both sets are set to the exact same frequency and if they have a small toggle switch for 12.5KHz operation it is set the same

3. Both sets are in the squelch off position - preferably old squelch

4. Power on and lots of squelch noise in the handsets

5. Press the PTT on a set and the squelch noise stops while it is pressed. Do the same on the other set.

6. If the squelch noise does not stop it is not transmitting

7. If it is transmitting have someone listen on the other set for your signal - the squelch nois should stop while a signal is being received. If the squelch noise stops but there is no audio you may have a handset or audio circuit problem.

8. If no signals are received in either direction it could be that the transmitters are faulty. However it could be that one of the sets has been assembled incorrectly and the frequency is not that shown on the dial.

At this point you need to get hold of someone with a suitable power meter and measure the power of each set on transmit. If there is no power they have faulty transmitters. If there is power one, or both, could be off frequency. You then need someone with a frequency counter to check it.

You could also try using them against a known working set.

As for working with modern equipment, they should be able to if the modern equipment is on the same frequency, not set inencrypted or frequency hopping mode and is on fm.

Hope this helps.

Howard
Howard

Daimler Ferret Mk 1/2
AM General M151A2
Austin Champ

kmam
Sergeant Major
Sergeant Major
Posts: 524
Joined: June 6th, 2015, 7:39 am
Location: Kuranda, Far North Queensland, Australia

Re: Prc 77

Unread post by kmam » November 29th, 2016, 4:55 pm

To mount in your MUTT you need an am2060, the mounting tray for it plus the sponson plate. Can't recall the numbers for the last two parts off the top of my head. They are the same for the AM2060 and the RT524.

You will also need an antenna system plus cables. Again, too early (just woke up) to recall part numbers but power cable is cx4720 and cable to control the antenna tuner is cx4722.

If you need more info let me know and I wiil dig it up.

Howard
Howard

Daimler Ferret Mk 1/2
AM General M151A2
Austin Champ

Husker
Master Sergeant
Master Sergeant
Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Prc 77

Unread post by Husker » November 29th, 2016, 8:39 pm

Ok so starting off I am using military magnesium batteries with unknown power levels (both can operate back lite)

When set so squelch radio 1 at max volume makes very limited static

When set to squelch radio 2 at max volume makes a good amount of static

Both sets stop static when you key there PTT and voice will sometimes transmit

Radio 2 when the PTT is pressed and released a pound fuzz is produced over the normal static

I think I really just need new battery adapters
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

kmam
Sergeant Major
Sergeant Major
Posts: 524
Joined: June 6th, 2015, 7:39 am
Location: Kuranda, Far North Queensland, Australia

Re: Prc 77

Unread post by kmam » November 29th, 2016, 8:55 pm

The NOS magnesium batteries are generally not usable. You can buy adaptors for D Cells which is probably the best way to go. These are available from Brooke who makes them and sells them on prc68.com. They are also available from eBay.de - these are ex-German Defence Force and quite good units. If you feel up to it you can disassemble the magnesium battery and rebuild it with D Cells but it is a bit messy and not as easy for long term use when you will want to replace the D cells every so often.

Alternatively find someone with a PRC77 mounted in a vehicle who will let you slide his out and yours in so you can test it.

Howard
Howard

Daimler Ferret Mk 1/2
AM General M151A2
Austin Champ

Husker
Master Sergeant
Master Sergeant
Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Prc 77

Unread post by Husker » November 29th, 2016, 10:37 pm

Thanks I ordered 2 from Germany they were much cheaper and look pretty durable
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

User avatar
pvtwinger
Staff Sergeant
Staff Sergeant
Posts: 100
Joined: October 28th, 2013, 8:24 am

Re: Prc 77

Unread post by pvtwinger » November 30th, 2016, 9:12 am

199th mp wrote:set both of them on new squelch, off. do both handsets work? also, they will not commo with new radio gear at all. completely different.

I agree with most of what you say here, except that the PRC-77 only has the "new" squelch, using the 150 hz tone on transmit. It does have a squelch off switch but this would have no effect on transmit just in receive, and whether squelch is on or off it does transmit the tone so should break the squelch on another PRC-77.

Also, the PRC-77 has only one power level, approx. 2 watts. There is no high and low power switch like the RT-524 has.

I have both PRC-77s and later model SINCGARS PRC-119 (RT-1523) and these radios definitely WILL communicate with each other if the RT-1523 is in SC mode (Single Channel) and not in FH (Frequency Hopping) mode, and set to the same freq. The PRC-77 covers 30-75 MHz, and the RT-1523 covers 30-88 MHZ, so there is only a small range, 76-88 MHz where the PRC-77 does not operate on.

The mounting tray you need to mount the AM-2060 is the MT-1029, and you will need a power cable CX-4720 to power the unit from the batteries.

I''ll just mention this for your info, but you do legally need an Amateur Radio license to operate these radios, and then, legally in only the 6 meter ham band, approx. 50-53 MHz.
1979 AM General M151A2 "Barstow"
1972 AM General M151A2 (Sold 2020)
1987 AM General M1026 HMMWV (Sold 2012)
1986 Chevy M1009 CUCV Blazer (Sold 2006)
2 M416 Trailers (Sold)

K3YYZ

kmam
Sergeant Major
Sergeant Major
Posts: 524
Joined: June 6th, 2015, 7:39 am
Location: Kuranda, Far North Queensland, Australia

Re: Prc 77

Unread post by kmam » November 30th, 2016, 9:25 am

Ah, correct. I have a 77 set, a 25 set, RT524 and a 442. Was thinking of wrong set when talking of old squelch :(

I modified my 77 set to use carrier squelch instead of tone squelch so I could use it with commercial radios. Got a licence from our authority to use 72.350MHz which I sub licence for our military vehicle club members.

Howard
Howard

Daimler Ferret Mk 1/2
AM General M151A2
Austin Champ

Husker
Master Sergeant
Master Sergeant
Posts: 374
Joined: August 26th, 2016, 1:52 pm
Location: Fairfax Virginia

Re: Prc 77

Unread post by Husker » November 30th, 2016, 10:11 pm

How did you get your 77 to talk with hand held radios?

I would love for them to talk to my baofengs or vhf vehicle radios
US Army Fort Belvoir

19XX M35 something. Sold......
1972 M151A2
1967 M416
On the hunt for an M1031

Post Reply