VRQ/RT-67/68

LoboMike · Post by **LoboMike** » Fri Jul 14, 2006 8:39 am

I'm going to keep both my MT-299's. I've decided to mount a VRQ/2 & 3 on each rear wheel well.

One question I do have is about wiring them up. One mount has one power cable in and two out (receiver & power supply I assume) the second has one power cable in and four out, what are the two additional cables for?

Also, my plan is to bring power to the left VRQ (probably the 3) and "link" the other power cable into one of the two "extra" power slots in that Mt-299. Any thoughts and/or suggestions?

Simply put I hope to power the VRQ/3 in typical fashion from the power source by the passenger seat and the VRQ/2 from that MT-299. Hope this all makes sense.

Thanx all, Mike

Post by **wesk** » Sun Jul 16, 2006 9:53 am

That would work so long as you took care not to operate both sets at once. It's not that difficult to run a completely seperate power lead kit from the battery duplicating the existing one.

You'll see in these photos that the MT-299 for the VRC setup has only 3 power cables (1-in from jeep, 1 out to pwr supply. The other cables originating on the mount are carrying miscelaneous control circuits between the control, the RT and the peripheals.

In this photo of the VRQ's block drawing you see the MT-298's three power cables. One in from jeep and one to each pwr supply.

LoboMike · Post by **LoboMike** » Mon Jul 17, 2006 6:04 am

Thanx Wes, very helpful.

My plan is to run the power cable from the first unit MT-299 from the power side terminal to the power side terminal of the second MT-299, I guess you could say one long power cable with an intermediate connection to first MT-299. This takes advantage of the originally installed power connection by the passenger seat.

I can't see how this differs fromrunning two separate power cables. Am I missing something? Load on cable shouldn't be excessive, should it? Each unit would still retain it's own fuse circuit protection. Wish I could diagram this.

Again thanx for all the help, Mike

Post by **wesk** » Mon Jul 17, 2006 7:08 am

Depends on what equipment is operating at the same time on your jeep. The original radio power harness from the battery to the outlet by the pass seat is designed for 10 to 15 amps. Each of your two VRC style sets will draw about 7 1/2" amps when transmitting for a total of 15 amps. The complete VRQ type set you are duplicating as two seperate VRC types was not designed for both RT's to transmit at the same time. In their normal ops mode with one RT in transmit (7 1/2 amps) and one RT recieving (1 1/2 amps) the total load was only 9 amps. Be sure to make your patch power cord wire size equal to or greater than the power in cordage to the first 299 from the jeep. Also inside the junction boc you should piggy back the patch cord on top of the same terminal lugs the power in cord is attached to on the first 299.

Also bear in mind that the jeep's generator is only rated at 25 amps total with 10 to 15 amps being used in normal ops at night.

This is why when you see later USMC radio M38A1's they are equipped with the heavier amperage alternators.

Post by **wesk** » Mon Jul 17, 2006 7:11 am

Depends on what equipment is operating at the same time on your jeep. The original radio power harness from the battery to the outlet by the pass seat is designed for 10 to 15 amps. Each of your two VRC style sets will draw about 7 1/2" amps when transmitting for a total of 15 amps. The complete VRQ type set you are duplicating as two seperate VRC types was not designed for both RT's to transmit at the same time. In their normal ops mode with one RT in transmit (7 1/2 amps) and one RT recieving (1 1/2 amps) the total load was only 9 amps. Be sure to make your patch power cord wire size equal to or greater than the power in cordage to the first 299 from the jeep. Also inside the junction boc you should piggy back the patch cord on top of the same terminal lugs the power in cord is attached to on the first 299.

Also bear in mind that the jeep's generator is only rated at 25 amps total with 10 to 15 amps being used in normal ops at night.

This is why when you see later USMC radio M38A1's they are equipped with the heavier amperage alternators.

You should locate a copy of TM 11-286 for the VRC sets, TM 11-289 RT's 66, 67 & 68 and TM 11-5036 PP-109 & PP-112.

LoboMike · Post by **LoboMike** » Mon Jul 17, 2006 9:14 am

Thanx again Wes,

Definitely no plans to transmit simultaneously, fact will hardly receive at same time. I hardly ever use my M38 at night, except returning from parades, etc., and radios would be powered down at that point.

Powers cables are all the same gauge.

I'm working from TM11-284, I'll seek out the others.