I think we are chasing our tails here, folks. Snowbird says that she gets the
interference on her handheld. Let's do the binary troubleshooting tree.

Split the problem into two parts. It is either IN the aircraft or OUT of the
aircraft that the problem is located.

Depending on how often this problem occurs (once a week? once a day? once an
hour?...) DRIVE the handheld out near the antenna farm and sit there and listen
on one of the most affected frequencies.

Does it still happen? Then with 99% probability, you've got a problem not of
your own making.

Does it not happen? Then you've got a problem in the aircraft.

Let's settle THAT one and we can go from there.

Or, rather than drive out and sit for hours in the wintertime, do you have any
friends that live near the farm? Would they be willing to sit your handheld in
their window and listen for a few days?

All else at this point is conjecture.

Jim
Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com