I am happy to report that the RF problem I was having with the Trutrak autopilot has been solved. One of the posted suggestions pointed to a filter adapter that is installed between the controller and the harness. I ordered part number FCE17-B25AD-250 from Digikey for about $25 and it cured my system. Not a hint of interference from either radio.
thanks to all who wrote in.
Chris Zavatson
N91CZ
L360std