"JB" wrote:

Hmmm...my problems occur WITH the external antenna (suction cup
mount).

I use the external antenna, too.

Maybe it's interference from one of your radios. I've replaced two
Cessna ARC-385s because they messed up my GPS reception.

Or it might be your antenna, as Jonathan suggested. I had one develop
an intermittent open circuit in the cable where it entered the antenna.

--
Dan
C172RG at BFM