Hi Keith,
did you ever think about making the sound more realistic, closer to what we hear on the radio in real airplanes?
I am talking about hearing mic clicks, adding little white noise and filtering out the high and low frequencies from the sound by runing it thru an audio filter.
I know it's not your high priority and I am sure there are more important features, but I think it would be really cool to hear that "white noise sound click" at the end of each transmission.
Just an idea.
Rob