If this is RF interference than there does not have to be a physical electrical connection.
Route all cables for both devices as far away from each other as is possible. Separate the two (and all their cables, antennas/receivers) by at least three feet. Check the antennae cable and connectors to make sure that there is no exposed wires. I have heard that incorrectly installed connectors on VHF radios are large radiators of RF energy.