Question on Modifying Military VHF Antennas

[Mutt Hunter]

Gents,

I have a VRC-83 ground to air set-up for my MUTT. I used to carry the PRC-113 and do ground to air stuff, so putting the vehicle variant in my MUTT was an easy choice. However, finding a military dual band antenna has been impossible up to this point. The radio operates from 116 to 150 MHz VHF; and 225 to 400 Mhz UHF.

Here's my question: Since the SINCGARS family operated at 30-88 MHz in a spread spectrum, freq hopping way...can the AS-3900 antenna be shortened (cut) to accommodate the higher freqs of the VRC-83 listed above?

Clearly, i'm not calling in MEDEVAC, jumpers, or precision fires, i'm trying to impress chicks who like to listen to commercial aircraft and the occasional military ones flying into/out of MacDill AFB while i'm parked at some VFW or AM Legion bar.

So, can that antenna be shortened without impacting receive function at a higher freq? I've done the math and i know that the antenna needs to be 63.5 inches at 3/4 wave to have optimum performance in the middle of the 116-150 MHz range.

Thanks in advance to anybody that can answer that question...

dee

[kmam]

Having the antenna at the correct length is critical for transmitting but not so important for receive only. If the SINCGARS one is similar to the earlier model, it is a dipole, centre fed. so cutting it is only cutting one end of the dipole.

There really is no need to butcher the antenna. I am sure if you try it out, you will find that it receives fine.

[pvtwinger]

I used to have a PRC-113 mounted on my MUTT. I used a military aircraft blade antenna for use with the PRC-113. I fashioned a simple bracket and attached it to the corner bracket used to mount the MX-6707.

The AT-1108/ARC blade antenna has both a VHF and UHF connection since it is a dual band VHF/UHF antenna. I have since removed the PRC-113 from my MUTT, so the AT-1108/ARC is for sale, if you are interested. There are other military aircraft blade antennas available, but not many with both VHF and UHF connections.

[Mutt Hunter]

Sounds cool! You're the first person I've encountered since joining the hobby that had that set-up.

You have some pictures of it, and of the BNC connecting points?

I'm using the AN-7176 amp and a standard Harris mount (VRC-86) as its base station for power, etc. As such, I've only got the one antenna output--which i guess is pre-tuned for both VHF and UHF.

I'm going to try out the idea of a standard length antenna on receive only and see what happens...but i'm definitely interested in hearing about/seeing the blade antenna.

dee

[pvtwinger]

The antenna is about 15" high, 11" long, and 4" wide at its widest. There are smaller blade antennas but the military ones are mostly UHF only, not dual VHF/UHF. There is a BNC connector for VHF and a TNC connector for UHF. I have a TNC-to-BNC adapter that I used on it. You can see it in the photos.

Some hardtop FAC M151s mounted it on the roof.

https://www.dropbox.com/sh/fpl8l14twiqj ... KW6da?dl=0

[Mutt Hunter]

Were you running the antenna straight into the PRC-113, or did you have an AMP? My radio only has one antenna "port" for the twist-on donkey antenna.

Wondering out loud how you gave that blade two inputs?

dee

[pvtwinger]

I had the PRC-113 mounted in the RMT-2 mount, bolted to the fender. I used a MRC-82A battery eliminator to run the radio off the 24v vehicle power. The antenna was mounted within easy reach on the M151A2 corner bracket, so I just switched the RF cable from VHF to UHF, depending on what I was listening to.

[Husker]

I have the uhf/VHF military antenna basicly brand new paid a premium for it but never was able to find the vehicle mount for my PRC113

I’d be willing to sell it to you but I’d like to get my money back from it if you want to PM me we can talk

[Mutt Hunter]

PM Sent

[pvtwinger]

There is no mount to mount an aircraft antenna to a vehicle. You must make one or drill holes in the roof or hood to do so.
I offered you my AT-1108 but you never expressed an interest in it.

Mine is for sale for $75 plus shipping.

[Mutt Hunter]

Without any other frame of reference, i'm assuming Husker means this short vehicle antenna pictured below. The AS-3588 is the correct antenna for a VRC-83 vehicle set up. But again, i'm as deep as his original message.

[Husker]

Yes that is the antenna I have

[Husker]

Mutt Hunter
There is one of the AS antennas on EBay if your still looking