Japanese Self Defense Forces 11223 USB voice/fsk 17:13 UTC 26 March includes MP3

[jasmine]

so all morning i've been hearing these two guys talking in Japanese and then an FSK type digital signal then more talking. signal very strong. one sounded like they were in an aircraft, so i looked up the frequency and found that it is used by Japanese Self Defense Forces. I have previously picked up the Japanese Self Defense Forces on 6727 USB talking in English with heavy Japanese accents. i had no luck decoding the FSK as i am still very much new at digital decoding. if anyone else has any luck with the audio i included (Josh?) or know Japanese and can tell me what they were saying i'd appreciate it:
MP3 audio: https://drive.google.com/file/d/19dEtYs3BjmjOkp5yNuJb7MIfLm2tjO2g/view?usp=sharing

sidenote: this was my first long listening session with my new Airspy HF+ Discovery SDR. i originally bought an SDRPlay RSP1a as part of a meteor detection experiment before i got hooked on HF so i am returning the RSP1a to full time meteor detection duty. i love both SDRs but especially love the sensitivity and preselectors of the HF+ Discovery on HF.

[nickcarr3151]

Nice signal Jasmine.  Yes, the Pacific is open to a lot of stations in/around the Far East in the early morning hours.  Some days are better than others.  In ancient times, there were these 'dark spots' on the surface of the Sun -- humans called them "sunspots" -- and they would actually enhance HF communications especially during the summer months. 

Of course, these sunspots are a mystery in the cold, dark misery of present-day times.

[jasmine]

Nice signal Jasmine.  Yes, the Pacific is open to a lot of stations in/around the Far East in the early morning hours.  Some days are better than others.  In ancient times, there were these 'dark spots' on the surface of the Sun -- humans called them "sunspots" -- and they would actually enhance HF communications especially during the summer months. 

Of course, these sunspots are a mystery in the cold, dark misery of present-day times.

i hear the sunspots are coming back as there was one just spotted (no pun) the other day: https://spaceweather.com/archive.php?view=1&day=08&month=03&year=2020

hopefully that news will brighten an otherwise dark time.

[Josh]

Konichiwa! Very nice catch! The BFSK is STANAG 4481, 75Bd/850Hz shift offline encrypted by our old friend KG84C


https://www.sigidwiki.com/wiki/STANAG_4481
https://en.wikipedia.org/wiki/KG-84


Here's your secret message;



Detected KG-84C SYNC with 92% confidence
Initialization vectors: 7D58AADC2A825673 C65BFF94B8CBE16B
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
End of message (idle pattern)


Both Sorcerer and K500 have demodulators/detectors/parsers for S4481 and KG84 use. That said, once you hear an init to KG84 via fsk you'll always recognise it. Most USN S4481 traffic is going to be KG84 or newer encryption device, so when you see/hear 850Hz 50/75 Bd fsk think USN or NATO or Japan.
Konchow for the nice recording.

[jasmine]

thank you for that! i had no idea K500 could do that.