Been using one for years on my mutt, you can see it in the attached picture right next to the regular scoop mount for the little VHF whip for the URC-110 I think its far better then the newer round tuner because it can be easily disassembled and has adjustable coil and capacitor for each of its four preset bands so I was able to tine the card that covers 51.0 for 51.0 and get best match that way. Also the antenna works as a two part vertical dipole with the bottom being isolated from ground.

Don’t know it to be a fact but have been told it is the correct ATU for the VRC 12 family during Vietnam and have to wonder about all those hundred point “show” mutts equipped with the newer ATU?

Ray F/KA3EKH

From: [email protected] <[email protected]> On Behalf Of comcast
Sent: Thursday, June 6, 2024 4:22 PM
To: [email protected]
Cc: [email protected]
Subject: Re: [MRCA] Commo #4 MX-6707

folks. back issues of ps magazine had some tips for the care and use of the 1729   I believe there is a drain hole that has a screw that needs to be removed every some often to let water out.  but by then it could be too late.   jeff

Sent from my iPhone

On Jun 6, 2024, at 2:16 PM, Chance Wolf via MRCA <[email protected]> wrote:

What a score that was. 

There’s lots of pics of them in use on M151s in Southeast Asia if you look.  They were also the AMU used on the AN/MRC-108 FAC pallets.  They were a little more versatile mounting-wise than the MX-6707s because the spring base itself could be unbolted and re-oriented so you could mount the tuner base horizontally or vertically, both of which you see on VN-era M151s.   Countries like Canada would mount them as one tuning base in a two-set installation and use an MX-6707 for the other on pre-ROPS M151s and M38A1s.  

Interesting to see them made as late as 1986.  Who was the manufacturer?  I don’t think I’ve seen any later than 1968 contracts and I think they were all made by Magnavox.  Really high-quality bits of kit, those. 

From: [email protected] <[email protected]> On Behalf Of [email protected]
Sent: Thursday, June 6, 2024 10:18 AM
To: 'Tim' <[email protected]>; 'MilComm Guy' <[email protected]>
Cc: [email protected]
Subject: Re: [MRCA] Commo #4 MX-6707

All-

I was able to purchase two NOS in box MX-2799s with whips and all mounting accessories recently for $50 at the Phoenix MV show.  Most people don’t know what they are and pass them by!

I had thought they were used exclusively on armored vehicles, but I guess they pre-date the AS-1729.  Anyway, the units I purchased were manufactured in 1986.  Looks like it belongs on my  M-715.  Probably a bit much for a poor little MUTT!

Scott W7SVJ