Bill and Silvio--

Thanks for the advice. Today I'm borrowing a Lightspeed Zulu headset and will fly around the pattern and talk to tower wearing those.

I called ICOM and tech support advised setting the MIC1 SQL as high as possible and the MIC1 GAIN as low as possible. The INCOM LV1 is set for comfortable intercom volume. Those three settings affect ONLY the Intercom audio not the transmit/receive. (If I were using a passenger headphone, the same settings would apply to #2.) I didn't ask, but I believe the ANL setting [ON/OFF] only affects audio from the receiver, not the intercom. I turned ANL on.

Additional things I learned about the IC-A210: The SIDETONE LV is only effective when transmitting; The HP LEVEL (headphone volume) needs to be set to "AF gain" so the volume knob on the front panel controls the headphone volume as well as the external speaker volume. To get the display as bright as possible, I had to set the DISP MODE to MANUAL and the DISP MAN to 100. In the AUTO mode, the display was barely readable.

I really like the features on the IC-A210 and hope I can eventually get it set up correctly.