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Old 06-05-2018, 10:17 PM
Token Token is online now
Join Date: Jun 2010
Location: Mojave Desert, California, USA
Posts: 1,960

Take an audio recording, and do it in USB with the widest bandwidth filters you have, otherwise you are not going to actually have an answer.

Based on your descriptions:

This is probably not the sounder for the 29B6. The 29B6 has not been active in many months now, nor has the sounder been seen.

If it sounds anything like the old Woodpecker or the 29B6 sounder it is probably not PLUTO or PLUTO related. PLUTO has one mode that is at a somewhat similar rate, 12.5 Hz vs the 10 Hz of the 29B6 sounder and the old Woodpecker. However it (PLUTO) normally does not use that rate with its standard 20 kHz width. Yes, it can use that combination, but it is uncommon.

Neither the 29B6 sounder nor the PLUTO in its 12.5 Hz mode is up and down the way you describe the signal you heard.

More likely, either the Australian JORN in frequency hop mode or a Chinese skywave OTHR in freq hop mode. However neither of those typically has a rate near 10 Hz, to sound like the Woodpecker or the 29B6 sounder.

But without a recording that is the best you are going to get. Comparing it post event to recordings online is not going to clear it up, as there can be too many that sound similar.

By the way, the old Woodpecker is never coming back. The sites have been dismantled, except for the one receiver only location that people see in pictures, and it is scrapped except for the antenna structure. Also, the technique used was really wasteful of bandwidth by comparison to any OTHR on the air today, and produced less detailed information. You just are not going to see such a long pulse with BPSK coding in use for that specific application again, technology and processing power has passed it up. I am not saying such a waveform does not have applications, but skywave OTHR searching for missiles and aircraft is not the forte of that kind of waveform.


Last edited by Token; 06-05-2018 at 10:27 PM..
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