davham, I answered this question in depth last night but the post disappeared.

I cannot believe it is a field problem if others aren't having it, too.

I believe you said it happened on ch 43 and 53. Is there some way you can get one of the planes on the lower half of the 72MHz band? Can you swap with someone?

It is possible that channels 43 and 53 are the only ones affected my intermod, but doubtful.

I am an antenna engineer, so I take these things seriously, as do you, I'm sure, but I am not convinced by what I've read that there is a field problem.

Dig into this will you, and keep us posted.