- Location: Michigan, USA
- Frequency: 7.074 MHz
- Time: 1300 UTC
- Vertical axis: 15 seconds per division
Most of this is FT8, and some JT65 can be seen as well. But buried in here is something else, labeled "A". It appears to be some kind of 8-FSK, possibly with the same 15 second interval as FT8.
Labeled "B" is a similar signal, though it appears to have a wider tone spacing.
What are these "A" and "B"?