Loggings > HF Mystery Signals

UNID 6985 (CF) 1310 UTC 09 JAN 2022

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~SIGINT~:
UNID 6985.0 kHz (Centre Frequency) 13:10 UTC 09 JANUARY 2022

Note: UNID with a different sound / data modulation scheme from previously noted HFT. Unconfirmed but this is most likely also part of the high-frequency trading (HFT) HF network experiment.

13:10 UTC - UNID UTE with 4.4 kHz wide signal and unknown data format;
13:28 UTC - ALE from 6981.0 kHz bleeding through;
13:30 UTC - The signal is considerably fading out to my location;
16:10 UTC - Switched to the end-fed longwire antenna and the UNID UTE is still transmitting with an S7 ~ S8 signal to my location;
22:43 UTC - Signal level is now a good S9+ to my location;
02:00 UTC 10 Jan 2022 - Signal is still active, good readable.





Sample audio file: http://www.milspec.ca/board/media/SDRuno_20220109_175739_6985000HZ.mp3

RSPduo | Barker & Williamson & End-fed Longwire antennae | Toronto, Ontario Canada

~SIGINT~:
Update: 10 January 2022

A reliable source has indicated to me that the waveform is 4 x MFSK4.

Token:

--- Quote from: ~SIGINT~ on January 11, 2022, 2309 UTC ---Update: 10 January 2022

A reliable source has indicated to me that the waveform is 4 x MFSK4.

--- End quote ---

Yes, its most common mode observed recently has been what looks like 4x4FSK or 4xMFSK4.  That is, 4 channels of MFSK, each channel with 4 shift tones.

However, it has also used 3xMFSK4, 4xMFSK3, and a couple of other formats.

One format had a total bandwidth of 2.4 kHz, and consisted of 1xMFSK3, 1xBFSK, and 1xMFSK6.  It is possible this was actually a 4xMFSK4, but channel 2 had only data hitting 2 MFSK tones and channel 3 and 4 were so close together that it looked like 1 MFSK6 instead of 2 MFSK3's.

The total bandwidths seen have been from under 2 kHz to over 12 kHz.  4 kHz and 10 kHz appear to be most common in recent use.  It is not uncommon to have up to 3 transmissions or possibly channels right next to each other.

T!

T!

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