HFU HF Underground

Loggings => HF Mystery Signals => Topic started by: alleycat on February 27, 2022, 0346 UTC

Title: Unid 11318 dig (2-second bursts preceded by short tone)
Post by: alleycat on February 27, 2022, 0346 UTC

Approximately 2.4 kHz wide, 2-second long digital bursts preceded by a very brief tone; usually individual bursts, but sometimes 2 in a row. Closest match I can find on SigIDWiki is STANAG 4197, but 4197 appears to have a multiple-frequency opening tone, whereas my signal has a single tone.
Audio clip: https://www.lutins.org/temp/sdr/11318_burst.mp3 (https://www.lutins.org/temp/sdr/11318_burst.mp3)
Waterfall: (https://www.lutins.org/temp/sdr/11318_burst.png)

Title: Re: Unid 11318 dig (2-second bursts preceded by short tone)
Post by: ~SIGINT~ on February 27, 2022, 0355 UTC

This is HFDL - High Frequency Data Link, the HF version of ACARS.

High Frequency Data Link
https://en.wikipedia.org/wiki/High_Frequency_Data_Link (https://en.wikipedia.org/wiki/High_Frequency_Data_Link)

https://www.sigidwiki.com/wiki/High_Frequency_Data_Link_(HFDL) (https://www.sigidwiki.com/wiki/High_Frequency_Data_Link_(HFDL))

Title: Re: Unid 11318 dig (2-second bursts preceded by short tone)
Post by: alleycat on February 27, 2022, 0547 UTC

Thanks! At one point in the past I had actually decoded HFDL signals using PC-HFDL, but it's been so long I forgot what I was hearing. Just used MultiPSK to successfully decode this one. There's so many modes it's hard to keep track of them all - I really appreciate your fast & helpful input! 73 de KC2KLC

Title: Re: Unid 11318 dig (2-second bursts preceded by short tone)
Post by: CoryD81 on April 12, 2022, 0037 UTC

The program Sorcerer among others decodes this mode quite well. Free too.