@blake I heard the morse code on my walkie-talkie this time; it was just sitting on channel 20 listening, while I was listening to the news on FM radio with my SDR. I assume it's probably a #GMRS transmitter somewhere, and it seemed longer this time, but I didn't switch back or turn on the recorder fast enough to catch it. 18:04 was the time on my screen when I looked up. I wonder if it's broadcast on a timer; nobody's responding to me on the channel.