We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissible in your locale.

Author Topic: UNID 6985 (CF) 1310 UTC 09 JAN 2022  (Read 1419 times)

Offline ~SIGINT~

  • DXing Phenomena
  • *******
  • Posts: 4106
  • N.E. Canada (FN08)
  • .ılılı..ılılı..ılılı..ılılı..ılılı..ılılı.
    • View Profile
    • Milspec Communication Canada
UNID 6985 (CF) 1310 UTC 09 JAN 2022
« on: January 09, 2022, 1331 UTC »
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
« Last Edit: January 10, 2022, 0217 UTC by ~SIGINT~ »

Offline ~SIGINT~

  • DXing Phenomena
  • *******
  • Posts: 4106
  • N.E. Canada (FN08)
  • .ılılı..ılılı..ılılı..ılılı..ılılı..ılılı.
    • View Profile
    • Milspec Communication Canada
Re: UNID 6985 (CF) 1310 UTC 09 JAN 2022
« Reply #1 on: January 11, 2022, 2309 UTC »
Update: 10 January 2022

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

Offline Token

  • Global Moderator
  • DX Legend
  • *****
  • Posts: 2118
    • View Profile
Re: UNID 6985 (CF) 1310 UTC 09 JAN 2022
« Reply #2 on: January 16, 2022, 1447 UTC »
Update: 10 January 2022

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

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!
T!
Mojave Desert, California USA