installation of GRC-160 radio set in my truck

[maddawg308]

I am planning on installing a GRC-160 radio set in my truck when I am further along this summer. For those not familar with it, the GRC-160 is the PRC-77 with a AM-2060 amplifier/power supply mounted on a MT-1029 mount. Same freq range as the PRC-77.

If I have the above set, what parts would I need to acquire to have the radio set in the center console area, with a mic up front and an amplified speaker mounted near the dash?

Here's what I gather so far for parts needed:

PRC-77 radio
AM-2060 amplifier
MT-1029 mount
CX-4720 power cable from battery to MT-1029 mount
CX-4655 jumper cable from AM2060 to PRC-77
CX-4722 control cable from AM2060 to control box
H-189 handset
AS-1729 antenna set (including MX-6707 base)
unknown control box?
unknown amplified speaker?

Thanks for the help.

 

[BillIdaho]

One might consider an MX7777 surge protector. They're about $20, fairly easy to find, and worth every penny as far as insurance against blowing a radio. You'll then need two additional cables, whose numbers escape me right now, without walking outside and looking inside on of my rigs. CX-10616, I think, along with a CX4720, (but with the three prong rather than the bare wires that connect to a battery).

 

[ONTOS66]

dawg:

I am picturing your M725 ambulance - where is the radio set going to be installed? In the cab or in the back? The installation is the same as most of the VRC-12 family. Your radio, amplifier and mount need to be secured someplace out of the way of traffic.

These manuals are available on LOGSA:
TM 11-2300-373-14-5, Installation of VRC-12 in M715
Parts list for PRC-77, GRC-160, etc. plus some of the manuals for the VRC-12 family

Naturally the operator / unit manuals are not approved for public release (gotta love LOGSA - they are consistent)

Are you going to get fancy and use an intercom setup, if so you'll wire it like a tracked vehicle, otherwise it is a fairly standard wheeled vehicle setup.

Where is the antenna going to be mounted, what style of mount (sugar scoop, newer style with brush guard, etc.)

Controls in the cab - M80 mike or handset? Control box - could be a C-2299 with a LS-454 speaker, or C-2298 if you want to do the intercom setup.

TM 11-5820-401-20-2 shows how to wire the whole setup and lists all the parts, components, cables, etc. for use with the intercom system and transient suppressor.
TM 11-5820-401-20-1 does the same thing but without the intercom system.

The cables you have listed plus the cables for the antenna.

Also the mini-suppressor could be used instead of the larger MX7777.
The MX7777 uses cable CX-10613/G to connect to the battery and cable CX-10398 to MT-1029.

Pardon the disjointed rambling, but I was flipping from here to manuals to other sites, etc.

PM me if you want more info.

 

[maddawg308]

Okay, one point at a time:

I am thinking about mounting a flat 1/2" piece of plate aluminum in the center hump area between the driver's seat and the passengers seat, on which to mount the radio, supressor, etc. The rear compartment door would be blocked, but I don't plan on doing a lot of movement between the cab and rear compartment through that little doorway. Plus, it seems odd to me to have a ham radio license, a military vehicle, and NOT mount a radio somewhere in it.

Would NOT use an intercom setup - too complex, and it's great for an armored vehicle with different crewman locations, but when the only users are going to be me and possibly the passenger, it doesn't make too much sense.

Antenna would probably be mounted on the passenger side rear of the patient's compartment, near the exhaust outlet, but higher up. I'd like to think there is a better location, but I haven't come up with one yet. Would use a sugar scoop mount, possibly with a CUCV style brushguard. Only thing I'm worried about regarding the location of the antenna, is because of the size of the metal rear compartment, how much interference will it cause in reception and transmission?

I would prefer an amplified speaker assembly, and I know the LS-454 is somewhat lacking in the decibel area. What's the amplified speaker that is most common nowadays, the LS-678 ? I can't remember the nomenclature. I guess an amp speaker and an M80 mic would be fine.

Why can't I use a standard CX-4720 power cable to run from the battery to the MX-7777? I believe the connector is the same, why go with the CX-10613/G?

Also, question on the AM-2060 and the MX-6707 antenna base. Both have manual antenna tuning switches on them - which takes precedence? If the antenna base is tuned to one freq and the AM-2060 to another, what happens?

Thanks for your help!

 

[BillIdaho]

The connector on a CX-4720 that would usually be used on a MT `1029, is NOT the same as the one needed for the input for the MX7777. Upon close inspection, you will notice that the outer ring is longer, the center bolt is opposite, for the terminal needed for the MX7777. They look the same, but are not. And you will notice that the cord from the MX7777 to the back of the MT1029 will need to be a little different. The output from th eMX7777 is three prong. Those particular cables are not very hard to find, nor very expensive.
As far as the intercom, unless your M725 is running a straight pipe right out of the engine, the cab ambient noise shouldn't be that bad. Not bad enough to warrant an VIC-1 intercom.

 

[OPCOM]

Haney Electronics has an amplified 'LS-454' speaker that powers the radio from 12V via a standard cable and it is plenty loud. It runs on 12 volts though so you would need a 24-to-12V converter. I understand the AM-2060 does provide manual switching to control the antenna base's tuning unit, but if you had a sincgars base you would not need that function. Maybe you could go with the AM-2060, because it does provide 12VDC (and 2.5V as needed for the PRC-25) and modify it. I have never had one apart, but maybe there is space inside to upgrade the amplifier to the one Haney uses and also beef up the 2060's 12v regulator section if necessary. Just throwing out some possibilities to get you the volume you want. Haney might be able to provide an amplified speaker that plugs into the unused audio jack on the PRC-77 instead of into the power jack, but it still needs 12V I believe. I think the amp is 8 or 15 watts. It is loud enough!

 

[ONTOS66]

Maddawg,

Don't know how much of this you have already, but ... someone has the installation kit on ebay
250122534745

Also, the AN/GRC-160 is vehicular and manpack unit, requires all the portable accessories. If it is just a vehicle install then it is an AN/VRC-64.

I think everyone has answered most of your questions. If you want a copy of the "integral components of end item" (don't you just love MILSPEAK) ... I have the TM and can scan the list for you. Shout if you have mo' questions.