HFU HF Underground
Loggings => Utility => Topic started by: ButchKidd on December 01, 2022, 2020 UTC
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Received via W3HFU KiwiSDR at S7 to S9. Appears to be National Guard net with ALE calls as well as MIL-STD 188-110A ARQ sessions. Could this be an HF mail system?
Interestingly, the 110A traffic didn't seem to stop during the ALE calls, so I'm not absolutely sure that the calling station wasn't transmitting on top of someone.
[No Timestamp][Call] [from MI5JOC ] [to WI5JOC ]
[No Timestamp][Call] [from MI5JOC ] [to IL5JOC ]
[19:35:58] [Call] [from MI5JOC ] [to MN5JOC ]
[19:41:55] [Call] [from MI5JOC ] [to OH51JOC ]
[19:47:46] [Call] [from MI5JOC ] [to WI5JOC ]
[19:59:31] [Call] [from MI5JOC ] [to IN51JOC ]
[20:05:00] [Call] [from MI5JOC ] [to IN5C ]
[20:11:20] [Call] [from MI5JOC ] [to OH51JOC ]
[20:17:11] [Call] [from MI5JOC ] [to WI5JOC ]
[20:22:58] [Call] [from MI5JOC ] [to IL5JOC ]
Link to recording:
https://archive.org/download/mil-std-188-141-and-mil-std-188-110-2022-12-01-t-19-59-17-z-8025.00-usb/MIL-STD-188-141_and_MIL-STD-188-110_2022-12-01T19_59_17Z_8025.00_usb.wav
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This ALE traffic all originated from the US National Guard JOC Net.
[No Timestamp][Call] [from MI5JOC ] [to WI5JOC ]
MI5JOC NGB JOC Net Mississippi
I personally don't like the Kiwi ALE decoder unless you enable all of the proper headers to see what the traffic is.
[20:22:58] [Call] [from MI5JOC ] [to IL5JOC ]
IL5JOC US Army NG IL Joint Ops Ctr.
The first 2 letters of the call sign should represent the State.
From your recording, the 110 traffic was a mix bag of 75 BPS LONG, 600 BPS SHORT and 2400 BPS SHORT and predominently 2400 BPS SHORT with a bunch of encrypted text.
22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
DATA RATE 75 LONG INTERLEAVER
DATA RATE 2400 SHORT INTERLEAVER
DATA RATE 600 SHORT INTERLEAVER
[EOM]
22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
DATA RATE 2400 LONG INTERLEAVER
[EOM]
1 0
DATA RATE 600 SHORT INTERLEAVER
[EOM]
1 0
DATA RATE 2400 SHORT INTERLEAVER
DATA RATE 600 SHORT INTERLEAVER
[EOM]
1 0
DATA RATE 2400 SHORT INTERLEAVER
DATA RATE 600 SHORT INTERLEAVER
[EOM]
1 0
DATA RATE 2400 SHORT INTERLEAVER
The one ALE decode was:
[HH:MM:SS][FRQ 08025000][TO ][IN51JOC ][TIS][MI5JOC ][AL0] BER 30 SN 08
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Yeah, I was sending the audio to external programs so I could try to decode them both at once. The ALE log is from Multi-PSK, and I truncated it down to just the calls. I suppose I should include the SINAD, BER, and LQA info as well next time.
I was able demodulate the 110 as well, but as you said, the actual traffic was encrypted. The short preamble on most of the transmissions makes me suspect a system that establishes a session between to stations with 75/long, and then switches to a higher bitrate with short preambles for the duration of the session. The long periods of 2400/short with little bursts of 600/short made me think about sending blocks of data with the receiving station sending ACKs/NAKs.