Lots of activity noted on the SDR recordings, some mentioned in more detail in other posts, but here's the frequency rundown:
6827 USB
6838 USB
6868 LSB
6870 USB
6875 LSB
6877.5 USB
6879 USB
6900 USB
6915 LSB
6922 USB
6925 LSB
6926 USB
6927 LSB
6948 LSB
6950 USB
6970 LSB
Lots and lots of frequencies. It's possible that with dedicated monitoring, some usage patterns could be established. For example I have often noticed the 6922 guys on the SDR recordings, I think around the same time, kinda late, 0600z or so? It's really a job for an SDR and overnight recordings, you can quickly spot stations and note the times, then to see if you can deduce net operating times, etc. All assuming they stick to a schedule of course
