I confess I don't understand a lot about RF, carrier, modulation, blah blah. When I completed the jack wiring, I turned on the center stack and rigged a temporary antenna to test my work. Pilot side - received VHF fine. Heard myself talking through intercom. Tried transmitting and while I did transmit, there was a squeal along with it. What to do.... Eventually, I determined the ground plane for the rigged antenna was poor. I relocated it to bare aluminum and clamped it to my top skin. Bingo. Pilot side works fine. Great reception and transmission quality. I did have to adjust the SL40 settings based on VAF postings with similar issues. Then the CoPilot side. I have a panel switch that activates the copilot stick grounds. Activated it and I could not hear myself on intercom. Would not transmit voice but I did hear clicking on the portable radio as I was pushing the PTT button repeatedly. Reception of VHF was perfect. Bottom line is I had inadvertently switched two wires when I soldered the mike jack. Took it apart and traced each wire to the audio panel. Resoldered the jack correctly this time and all problems solved. I even added a com1/com2 swap wire to the audio panel, activated by a button on either control stick grip. I love it now. Last issue to fix is too loud volume through the BoseX headsets. There are several adjustments I can make and will do that next.
