Radio Antenna Bases

[CARNAC]

Another point of confusion based on numerous pm's today. On the right is the MX-6707 which is used for 12 series radios. The 12 series radios are Vietnam era radios that were used up to and including Desert Storm. On the left is the AS-3900 for the SINCGARS. SINCGARS is what is currently being used by the military.

Both are about the same size but the bottoms are obviously different. Quick test is, if you can stand it up on it's bottom, it is an AS-3900. You cannot stand a MX-6707 up on it's bottom. The antenna is different between these two sets.

There is another base also seen in some cases called the Shakespear Low Profile Antenna. It looks like a smaller version of the AS-3900 and the actual antenna looks like wire that is a little thicker than coat hanger wire. I will get a picture of that one out also.

 

[Cdub]

Hi Medlog,

Thanks for showing us the difference between the AS-3900 and the MX-6707 antennas.

I know the MX-6707 is self tuning......but why isn't the AS-3900 self tuning as well......??

Thanks,

C'dub

 

[CARNAC]

Now that's getting a little technical but the best I can come up with is the TACTICOM website:

AS-1729/VRC Antenna - Used with vehicle installations which have the radio sets AN/VRC-12 series, AN/VRC-53, AN/VRC-64, AN/GRC-125 or AN/GRC-160. The matching unit MX-6707/VRC tunes the antenna elements automatically or by manual selection via a selector knob on the base.

AS-3900/VRC Antenna - Similar to the AS-1729/VRC, this antenna is used with the newer SINCGARS FM radio sets AN/VRC-88, -89, -91 and -92. As with the AS-1729/VRC, it has a two piece mast and a mechanical matching unit. The Matching Unit MX-9446/GRC tunes the antenna automatically or by manual selection via a selctor knob at the base. The AS-3900/VRC has a frequency range from 30Mhz to 80Mhz.

AT-912/VRC Antenna - Predecessor to the AS-1729/VRC and has similar applications. Compatable with the AN/VRC-12 series, AN/VRC-53, AN/VRC-64, AN/GRC-125 and AN/GRC-160 radio sets, the matching unit MX-2799 provides automatic tuning of the antenna elements, but has no provision for manual tuning.

The AT-912 is a fairly rare find. The 3900 is strictly for SINCGARS and has no ability to do manual tuning.

I'm sure some of the techno-geeks (no offense) can provide a lot of technical info in why.

medlog

 

[roger-wilco-66]

Thanks for that great information!
Most likely the SINCGARS radios have the matching unit integrated in the radio itself, which makes an external matching unnecessary.

As a little addition there should be mentioned that theres a predecessor to the MX6707, the MX2799. See picture. It has an automatic matching unit in it, no manual tuning. It was used with the VRC12 radio sets, mainly with the RT246 (afaik...).


Mark

 

[maddawg308]

Has anyone ever seen one of those MX-2799s? If they are interchangeable with the -6707, and can find a mount for it, I might be interested in one. I guess if I can't find it on eGay, they aren't out there.

 

[vtdeucedriver]

Has anyone ever seen one of those MX-2799s? If they are interchangeable with the -6707, and can find a mount for it, I might be interested in one. I guess if I can't find it on eGay, they aren't out there.

I got a couple. Yes, if you look at M151's in vietnam, you will see that mount. Get your wallet out, they go high when there on there.

They are self mounting, there is no sugar scoop. You can see the mount holes for the bolts, it sits flat againsed the Extension plate on the corner mount of the MUTT. Maybe I will temp mount one on my mutt this weekend to show how it goes.

 

[mutt1966]

the MX-2799 is the base that would be used on VN vehicle restorations, the Gun Truck that were Aberdeen last year was using them if you look closly at my Avatar of the FAC 151 there is one being used on the left side behind the passenger door with the antenna base moved to the horizontal position. Scott out

 

[vtdeucedriver]

Yep, they got them. Like I said, the mutt and most vehicles had that antenna base...................I dont have a pic on a mutt at the moment but I did find this one

 

[vtdeucedriver]

Here is the base on a Deuce Gun truck.

 

[roger-wilco-66]

I want 2 of these MX2799 badly, but you hardly get them over here, and they are expensive.

 

[mutt1966]

I have this setup on my M38A1 they are hard to come by usally they are without the antenna base you just find the box then ya hav ta find the bottom section of the antenna section let alone if it works but on the up side they can be mounted vertical or horizontal and usally dont have the water leaking in as the 6707 does. Scott out

 

[pockersUK]

Hi any one tell me correct positioning for antenna on a M38a1 jeep - ie is it on the left (drivers) side or the passanger sde, om the rear wing

thanks

 

[vtdeucedriver]

Anyone need those mounts????? I have a couple that I will sell.

 

[vtdeucedriver]

Will sell or trade!

 

[98hd]

Interesting info. I was wondering what the base on my M818 was for, I can remember seeing the switching on the bottom so it must be a MX-6707 .

Can the bases be adapted to work with anything other than the 12 series radios? I think it would be neat if it could be made to work with a FM radio or CB, for a correct look, but for something more functional to me than a 12 series radio.

 

[Boatcarpenter]

98hd, I adapted an older style CB ant. to a sugar scoop. Here is a pic.
BC

 

[bulldog_mack13]

Anyone have the current antenna and base and mount(entire kit) to mount on a M35? - Jay

 

[OPCOM]

Here is the SWR curve I measured of the AS-3684 SINCGARS antenna unit, substantially similar to and the predecessor of the AS-3900. Like the AS-3900 unit, it requires no tuning.

Also, for fun I have included the curve of the AT-667. It is made for 148-171 MHz, but will work decently on the 2M ham band. These antennas show up and no one know what they are good for, so they go cheap.

 

[Elwenil]

The MX-6707 base can be made to use with a CB. Basically you gut the base, install a common CB cable jack and wire it directly to the antenna poles. There are instructions somewhere on the net. If Mcinfantry is still around, I believe he did a writeup years ago at The M715 Zone.

 

[98hd]

The MX-6707 base can be made to use with a CB. Basically you gut the base, install a common CB cable jack and wire it directly to the antenna poles. There are instructions somewhere on the net. If Mcinfantry is still around, I believe he did a writeup years ago at The M715 Zone.

Thanks, for the info, I may just do that.