-lots of good info coming out of all these replies.  I did just speak with folks at Trutrak.  Based on the testing they having done in house, the current path is to look at the ground path between the autopilot controller and the radio stack.  This concern has been coming in from multiple sources off-list as well.  Plastic airplanes have more opportunities to miss in this area.  The one thing they said it would not be is radiated energy directly off the antenna.  All this assumes good VSWR for the antenna causing the problem i.e. the antenna installation itself is in good condition.  Since I have already confirmed this across the entire com frequency spectrum, I am jumping straight to step 2.

Thanks for all the input.  Updates to follow...

 

Chris Zavatson

N91CZ

L360std