[Milsurplus] M151 radio instalation

[Ray Fantini]

The DC question: I am in the process of loading down the back of my M151A1 with an AN/GRC-106 and a URC-110 the 106 is mounted one on top the other on the driver's side and the URC is mounted over on the passenger's side where you would usually find a VRC-12 installation. I figure that everyone who owns a M151 has a VRC-12 stuffed into it so I decided not to go that route and am doing the huge HF/SSB and VHF/UHF installations. After much time and research I finally have all the shock mounts, mounting plates and all that sort of stuff finished and am now at the point of having to work out primary DC connections for the radios. The URC base has a signal four pin power cable that's appears to me to be identical to what's used in the VRC-12 installation and without the amplifier will only be drawing a couple amps in transmit at the most but the 106 will suck down around thirty to thirty five amps in transmit and several amps in standby. The RT-662 receiver exciter is fairly efficient drawing maybe over two amps in receive and the AM-3349 is under ten in standby so the current drains are not that bad when not transmitting. The receiver exciter and the amplifier both have their own power cables. So in review I will have three power cables, two that will be under ten amps normal service and one that will be under forty amps in transmit only.  The GRC-106 installation paperwork for the M151 shows running both DC cables across the back deck in a channel that I don't have yet directly to the battery compartment and I figure the URC cable can run to that compartment also. There are already holes in to the tool compartment and then to the battery compartment that have been provided but the question is should I instead bring all the power cables together to a central tie point somewhere around the radios and then extend just one huge cable to the battery? Or maybe have a box with circuit breakers in it where they can be isolated at that point? Was thinking of something like the MX-7777 but from what I read that was never used on the M151 and was intended for vehicles where they had issues with transient voltages or spikes. Or do I just extend everything directly to the batteries like the book shows? Problem with this is I will end up with the original battery cable and three others now in the battery compartment and being that I am also looking for the 60 amp alternator to replace my stock 25 that will be another cable entering into that aria, by the way if anyone has a sixty they want to sell let me know. The thing I keep thinking of is if I should have a master disconnect switch for all the radio equipment or maybe a contactor to isolate everything? Or just do the install the way the government designed it? Any thought or ideas welcome.

Ray F/KA3EKH
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