Mystery Multiplex Signal

[mmcc]

I see this signal, sometimes for several hundred KHz, sometime for over 1MHz, spanning anywhere from 2MHz-70MHz.



1.  2MHz-70MHz (bandwidth of several hundred KHz to 1MHz)
2.  Visible 24/7
3.  Continous (Can sometimes switch on/off on certain frequencies)
4.  Receiver Mode - N/A
5.  UK
6.  Looks like a multiplex signal.  Has an unstable modulation of around 25Hz.

For reference, here is the audio:
https://www.sigidwiki.com/wiki/Unidentified_Signal_5

Any ideas?

[BoomboxDX]

Dumb question time: You're certain this isn't some sort of RFI?

Does the signal propagate? I didn't hear any obvious fading in the sound clip.

Personally, I haven't heard anything exactly like that signal. The closest noise to it is OTHR (over the horizon radar).  The famous Russian Woodpecker of the 1970's and 80's had a similar sound and pulse rate, but it also moved around a lot, and most times you could hear fading of some sort.

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