For those of you looking at the Phase Shift Key idea for the Symbol - I am really liking that these days
I am seeing what im calling a carrier wave in the UP signal. I have been playing with some Ham Radio software (Ham Radio Deluxe) and there is a nice sine wave that is coming from the UP at around 1500 Hz. So far I have not been able to make much of it ...
You might be onto something here. I have Hamilton Radio Deluxe installed on an old T61 that's currently boxed up with my radio from moving a couple months ago.
One of those signals does sort of look like it might possible be low bit rate psk. Psk usually looks a bit like DNA double helix and makes a distinctive warbling sound if it's not drowned out by other sounds.
You should be able to select one or more encodings as active for your HRD layout then click on traces in the spectrograph to have them decoded and displayed as text.