HFU HF Underground
Loggings => HF Mystery Signals => Topic started by: Antennae on March 11, 2015, 2202 UTC
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1. 9085kHz (between twin bursts)
2. 3/10/15 20:05utc
3. 5 sec intervals
4.XCVR mode: USB/LSB, DSB?
5.SW Coast USA
6. Mid-day, I saw some pips on the waterfall. These are short bursts of data. Sounds like a short burst of consecutive beeps of differing tones. There are twin bursts that are asymmetrical. Assuming the mode is DSB, every once in a while the USB burst will be one solid tone while the LSB has none. LSB sounds like lower tones and USB sounds like higher tones.
Here's a picture:
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I am not near a radio so I can't check right now, but that has the looks of an RTTY signal that is having issues.
The spacing is correct for 850 Hz shift RTTY, and I have seen RTTY signals show similar characteristics when there was intermittent audio or transmitter issues. I bet if you watch that freq for a while you will see STANAG 4481 FSK or similar, 850 Hz FSK, centered on 9085 kHz.
T!
(edit) Finally got home after a 20.5 hour day, not counting commute time, and did find an FSK signal on 9085 kHz. It does look like S4481 FSK, 75 Bd 850 Hz shift, KG-84 encryption.