I think Shadetree Mechanic might be on to something here.
we've been looking for commonalities with your antenna setups, coax, etc. but haven't thought about the radios because you said that it happens with different radios.
however!
the two radios you listed are pretty much identical on the inside and both of them are notorious for being aligned wrong, meaning for maximum noise as opposed to maximum signal.
this is very easy to do in this style of radio that includes pretty much every galaxy, connex, etc. out there.
so, were both of these radios purchased from the same place?
was it the same tech who did the alignments on your radios?
if so, it is probably the alignment of the radios that is causing your problems, which would account for the fact that it happened at your old location also.
could there be anything to this?
LC