Mike, Not being an EE (or anything close) I don't really understand what RX/TX "sensitivity" would have to do with a radio allowing noise (inverter, engine, or other) to interfere with RX/TX. I appreciate your input on this (seriously) but I think the larger issue goes to the ICOM POV - it's always somebody else's fault. The SH I installed is the Quantum GX 5500S. I believe the specs match up to the ICOM pretty well but again I'm no EE. Anyway, thanks for the input. If you are right that it's really a sensitivity issue then I would argue that ICOM needs a better understanding of real-world installations. (Again, no connection to SH) Bill