Unfortunately I haven't found how to put a sound file (WAV?MP3?) up here, but here's a coupel fo pix of my unidentified signal...It's still s9+ in the middle of the day.
This is a pic of the signal with 4248.5kHz in the centre and the gray outline is the filter bandwidth, so you can see that the 'noisy' signal fits neatly into 3.5kHz USB.
This is a waterfall of the sweeping signal. You can see that the 'noise' has a decreasing centre frequency in a sort of spiral fashion. the zero frequency on the left is 4248.5kHz. If I was going to describe the sound, I'd say it was like waves breaking on a shingle beach but slowly! Not so much the crunch as the wave falls, but the rattling all all those stones as the water recedes....how's you imagination!
Hope someone has seen this before!
