Many thanks to SWLing Post reader, Rick Slobodian, who writes to request help with the following:
[On Friday, August 19, 2016 at 1800 UTC, I noted a] “beeper”: beeps at Hz repetition rate , does not appear to be data, it beeps for about a minute then there is a short data burst then beeping again for a minute or two.
This went on for over an hour.
[The beeping covered] all frequencies between 13400-13800 kHz. [Then on August 20, it started at] start 1745 UTC and was no longer on 3400-13800 but now on
all frequencies between 12120 -12250.
What is it? [Take a listen:]
My ham radio friend says there are a network of stations that send out pings that everyone in the group transmits and everyone receives. The signal strength and phase of the rx signal is correlated at each receiver station, to direction find some unknown station.
Was there such a thing during the cold war, and is it still around? What is this system and where can I find out more about it?
Thanks for your inquiry, Rick. This is outside the scope of what I understand on the HF bands, so I hope SWLing Post readers can chime in and offer suggestions.
Please comment if you can help Rick ID this transmission!