Originally Posted by s/v Jedi
Well, there is your problem. The radar is overloading the VHF receiver.?
The odds of the emissions from the actual radar array on x or s band desensitizing the receiver of a VHF FM radio are very low. Look at the bridge of most tugs, freighters, and cruise
ships and you will see the VHF antennas in the beamwidth of the radar array.
I suspect it maybe a IF or intermittent frequency of the radar unit that is much lower than the primary transmit frequency. Maybe due to loose shielding or bad design but hard to speculate if you can't tell us if its been a long term problem or something that started recently.
One suggestion to see is get a VHF handheld and stand on deck
well below the radar (in a safe place) and tune around till you hear a station. Then have someone turn on the radar and see if they get weaker or drop out.