RFI to ant or pwr inputs
Usually, RFI gets into a radio either via the antenna or the power input. Wiring to other attached peripherals is a possibility, but far less likely. Could try unplug antenna and see if noise still there (I assume you hear it on receive). If so, the usual remedy would be to better isolate the source, or protect the affected device, reroute wiring, check shield grounds, etc.. If gone with antenna disconnected, then obviously it's the antenna location, connections, and/or the noise source must be lessened. I know there's different kinds of HID lights and some are supposedly far worse with RFI generation than others. One debate on shielded line, i.e. to strobes, etc., is do you ground at the likely source end of RFI or at the other end only, i.e. the power supply. Get into the same debate re field line to an alternator. Staying away from that discussion.