Hmmm, I ran into something I've never "seen" before. I tuned to a frequency and listened for a minute, heard nothing, called "QRL?" as I always do, nothing heard. Another moment, "QRL? de KE5FRF" as I always do the second time, nothing heard. I call CQ a few times, repeat my call a few times. I hear "dit dit" during the pause. I send "?" and I get a "dit dit" again, very strong signal. I am thinking someone is playing games, so I call CQ again 3 CQs, my call twice. I hear a faint station and it sounds like they are responding but I couldn't make it out. I send "sri QRN, QRN agn?" and I hear the station faintly again, and then another station calls THEM. I hear "dit dit" again a few moments later. All of this is zero beat, not off at the edge of my filter or DSP. I always get a little "upset" at myself when I think I might have caused QRM to a QSO, and since I didn't copy what the "faint" station was sending I have no idea if I might have had a sudden propagation shift that brought another QSO out of the noise. I wonder about the "dit dit" I was hearing. Could this possibly be another listening station that was trying to tell me I was interfering? I'm definitely not beyond learning a new protocol that I've never heard of before. Maybe the "dit dit" was a polite way of "tap tapping" me on the shoulder and telling me to be quiet?