First noted at 2233 utc with a big signal and bluegrass music. I had to walk away but left the SDR recording. I came back a few minutes later and noticed the signal was almost completely gone. Playing back the SDR recording, the signal took a major dive at 2236 utc, from S9 to almost nothing. Interesting. I need to read up on this "going long" thing. Looks like I just experienced it, and now I have a nice SDR recording to analyze!