16x64 Sounder Type Oddity

Ary Boender made a good recording of this enigmatic signal, which moves up HF with the same 16 bursts of 64 LFMCW sweeps at a declining rate. No one's sure exactly what it is, but it sure sounds like some kind of research transmission, possibly for ionospheric sounding. The first picture is a spectrogram of the whole transmission, then we get into the actual audio itself.

[@knottybank]

First tone sounds like the buzzer

[@artoodiitoo]

it´s a flying saucer with a rough idle

[@field16]

Thanks for sharing this radio recording and interesting sound!

[@Lunar_Capital]

This is the 16x64 sounder

[@Lunar_Capital]

***** Indeed. :)

[@insanedestiny5164]

That is the Air Force ALE net there (Automatic Link Establishment) conducting a test of their systems is what you are recording. Quite a daily occurrence

[@UtilityWorld]

That's a good guess. 8992 is of course an Air Force frequency, though it's HFGCS, not the newer ALE net.