Strong copy of the 4+4 DQPSK 75Bd Chinese modem on 17149.7 KHz/USB at 0915, 1128 and 1129 UTC.
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Fig. 1 |
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Fig. 2 |
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Fig. 3 |
Note the different periods in preamble, 36-bit length, and data segments, 12-bit length: most likely a 6-bit structure signal with 1 stop bit (Fig. 6)
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Fig. 4 - 36-bit period in the preamble segments |
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Fig. 5 - 12-bit period in the data segments |
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Fig. 6 - 6-bit signal |
The same signal was also heard few hours later (around 1130z) at -91dB and no QSB: too good conditions for a signal coming from China:
By the way, the Algerian Navy recently acquired three C28A Corvettes built in China [1] by Hudong-Zhonghua Shipbuilding Group, a subsidiary of China State Shipbuilding Corporation, this could explain the strength of the signal.
[1]http://www.defenceweb.co.za/...Sea&Itemid=106
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