Handheld radio interference

[Gritzlor]

Me and wife prefer to have VHF/UHF radios when riding. The problem is that no matter how far I turn the squelch, some interference opens the channels all the time over idle. At idle it is mostly OK. It also happens when I put the DESS key in, chirps along with the beeper actually.
The ski is a 2000 GTX RFI, in pretty good condition actually, our other identical ski has less of an issue like this.
Does anyone recognize this problem and maybe the source of it? I'm looking for some place to start with shielding, grounding, placing cable chokes etc.

...and yeah it doesn't really matter which band I choose, the garbage frequencies emitted seem random enough to open pretty much every channel.

 

[GGuillot]

Maybe better grounds in the ski, but if the skis are running fine, I'm not sure how you'd solve it. Have you tried different radios?

 

[Gritzlor]

Yes and different bands on my main radios which are dualband...VHF and UHF. Same thing.
Grounds are good, starter and ground cables new. I'm going to experiment with the DESS harness and maybe the beeper too since it seems to happen when I put the key in even if the ski isnt started yet.
Maybe I end up with putting all the harness in SS braid and ground it!