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Author Topic: UNID MFSK or PSK 7012.3 USB 0541 UTC 06 JAN 2023  (Read 978 times)

Offline ButchKidd

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UNID MFSK or PSK 7012.3 USB 0541 UTC 06 JAN 2023
« on: January 06, 2023, 0602 UTC »
There's been a nonstop data signal at the bottom end of the 40m amateur radio band for the better part of an hour.  The signal is about 2.5 KHz wide, and my best guess is that it's 12 PSK carriers.  I hear it at my QTH in the Southeastern US, but it's a lot more noticeable on online SDRs in the northeast.

UPDATE: added USB and I/Q recordings.



USB and I/Q recordings from N1NTE kiwi:
https://archive.org/download/unid-data-signal-7012.3-usb-0542-utc-06-jan-2023/sigmasdr.ddns.net_2023-01-06T05_41_21Z_7012.300_usb.wav
https://archive.org/download/unid-data-signal-7012.3-usb-0542-utc-06-jan-2023/sigmasdr.ddns.net_2023-01-06T05_42_51Z_7013.800_iq.wav

USB and I/Q recordings from W3HFU kiwi:
https://archive.org/download/unid-data-signal-7012.3-usb-0542-utc-06-jan-2023/sdr.hfunderground.com_2023-01-06T05_44_42Z_7012.30_usb.wav
https://archive.org/download/unid-data-signal-7012.3-usb-0542-utc-06-jan-2023/sdr.hfunderground.com_2023-01-06T05_46_03Z_7013.80_iq.wav
« Last Edit: January 06, 2023, 1210 UTC by ButchKidd »
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Offline Token

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Re: UNID MFSK or PSK 7012.3 USB 0541 UTC 06 JAN 2023
« Reply #1 on: January 06, 2023, 1615 UTC »
This is the Russian military AT3004D or AT3104D modem (the later is an updated version that supports more modes) in what hobbyist call the CIS-12 mode of operation.  The solid line to the right of the signal is part of it, a pilot or Doppler tone.  The frequency is 7012.0 kHz, USB mode.  When properly tuned the pilot tone is at 3300 Hz audio.

https://www.hfunderground.com/wiki/images/e/e2/CIS12.jpg

If you saw it with 20 QPSK channels it would be called CIS-20.

When idling the structure looks very different, and only the 3300 Hz tone remains the same.

T!
T!
Mojave Desert, California USA

Offline Josh

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Re: UNID MFSK or PSK 7012.3 USB 0541 UTC 06 JAN 2023
« Reply #2 on: January 11, 2023, 2007 UTC »
Yep, ruskii psk modemskii, the 3300hz doppler tone gives it away.
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