Listening this morning (Monday) in the UK on 3633 kHz at around 0300 UTC, I heard a strange weebly-warbly digital signal that continued for at least 15 minutes without a break (then it sent me to sleep).
The striking characteristic of the signal was that the data rate was very low (a few bits per second?), and the transition between the tones wasn't sharp -- it seemed as if each tone glided gracefully up/down to the next. At first I thought it was ROS, but I haven't heard ROS like this before. Any ideas on provenance? -- 73 Ian, G3NRW
