am/fm vhf

[champ]

When I turn on the am/fm radio it works fine until I turn on the VHF radio. Once I turn that on the AM/FM comes in weak, in/out, or not at all. VHF is always fine. Turn off the VHF and am/fm is back to normal.

This is something new. As I usually have both on at the same time.

Any ideas?

Thanks

[Capt. Debbie]

You have oscillator noise on your power feeds, Use an in line choke- coil.

Also you're not transmitting the VHF... that would be normal to splash the AM/FM

You have separate antennas right? Not that cheap crap combo antenna for AM/FM/VHF?

[champ]

thanks, yes - one antenae

[champ]

Correction - Yes I have 2 antenaes

[Capt. Debbie]

Two separated antennas are ideal.

When not transmitting on VHF, the vHF being on or off should not make any difference.

So it gets down to power & ground. If the electrical load of a non-transmitting VHF is affecting the AM/FM it's in the DC power feed or ground. To test... run a pair of wires from either radio directly to the battery terminals. See if that causes the AM/FM to peter out when both are drawing DC power.

This all assumes that the VHF radio is not problemed.