Any chance you know what frequency this is (in Hz?) I'm not sure exactly what the chittering is.
Ok, so... for the terminology:
- Howl is the big whale noise "starting a cycle" - it is the sound that is played when the UA lights up.
- Chittering follows right after the howl, and plays as long as the lights are showing - this is the Morse, the "data part" of the sound. I think it's about y=75 on your image.
(there is a sort of "encapsulating" sound curving up in pitch at the start, and down at the end - best heard about 300m out, most of my vids have this) This Morse code always spells out the name of the nearest astronomical object, regardless of you having cartographic data for it or not.
- Purrs are the trombone-like sounds, normally 2 types (hi-low) that play all the way, usually 4-6 in one cycle. They are sometimes present even during/under howls, and there's never 3 of the same type in a row ("rule of 2"). There has also been a mention of different pitched purrs, that seem to occur at the very beginning of the recordings, however I'm not sure if that took us anywhere.
There has also been work done transcribing these to a binary dictionary, it's in a spreadsheet somewhere. I would give credit because it's due, but my memory betrays me... halp?
- There's also a background noise, which again contains morse - always the same: VID 8 or HIB 8 according to people with better ear than mine.
In some videos, this background noise is gone, and the number of purrs per cycle goes down to 3 or even 2. This seems to happen with a lot of ships present, really close to the UA. This is an avenue we are still investigating.
NOW. What's interesting for me about the dynamic spectrum you made is that it's capturing more data than the ones I've seen in the higher regions. Question - can you confirm what's the sound around y=290 on your image? It also seems to "die off" about 2 cycles before the end. Weird.