don't whack them on everything
Actually, you do stick them everywhere
- one wire at a time. They don't work on coax cables but I don't think coax cables are the problem here, unless poorly earthed and even then I can't see what that frequency relationship would mean.
my avionics guy tells me it is a result of bleed over from the antenna being so close to each and the frequencies being so close.
That's a total lack of understanding of radio, if given as an explanation for the specific example given by drauk. If that was the case, having 117.0 and 117.1 on the two radios wouldn't work at all. Neither would 127.1 and 127.2 etc etc etc.