Batboard

I have a mobile install that involves two different radio systems that is experiencing some cross band RF problems.

One is a Dual Band UHF/VHF Icom 2800H 35/45 Watt mobile feeding a Larsen Dual Band Antenna.

Second is a Saber UHF w/SVA and Motorola UHF 45 Watt amp feeding a dedicated Larsen UHF antenna.

The antennas are seperated by maybe 3 feet on the roof of the vehicle.

The problem is upon keying the Icom at full power VHF (~50W) the UHF SVA Amp starts to self key causing a relay chattering. Only way to stop it is to remove the DC to the UHF amp or unkey obviously...

I am going to try a better grade of coax between the AMP and the SVA to try and eliminate this. I am thinking maybe the RF could be entering the 12Vdc line also.

Anyone else had a problem like this?

Personally I don't like using outboard amps but this is a good Ham buddy of mine that is trying to figure this out and he wants to continue using all his rigs in one vehilcle.

Thanks for any tips or hints,
Eddie
N4UMJ

Well, I spent some more time on this particular problem and found upgrading the coax from the SVA to the UHF amp did not help.

I did find out the RF (from the VHF transmitter) keying the UHF Amp is originating in the SVA snd only shows itself when the SVA is turned on. If the Saber in the SVA is turned off the UHF amp does not false or self key itself.

Now I am going to investigate checking the Saber SVA ground casing and adding a large ferrite bead to the incoming DC wires to the Saber SVA.

Probably will be awhile before I get around to trying this fix but will update this post with the results when I do.

Ed
N4UMJ