Neal really brings up a good question if we nitpick it a little. First, I agree that you should calibrate to 75 as you do with the other channels. But, the question of what frequency is a good one because the radio shack meter is less sensitive to the lower frequencies. Should we be applying a correction factor here or not?

Personally, I believe the answer to my own question is "No" because the tone sounds like all frequencies, not just one. I'm calibrated to 75 dB all the way around and I'm quite pleased.

Thigg, sign me up