Yet another interesting signal sent me by my friend Eddy from Australia. The transmission has been recorded on 16320.0 KHz/USB at 0520Z and consists of 200Bd/400 FSK-4 segments (the signal in between does not carry information). Figure 1 shows the measurement of the relevant FSK parameters.
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Fig. 1
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The first two segments A,B (the shorter ones) could probably act as selcall. Indeed, after the removal of the polynomial x^5+x^4+x+1, the stream exhibits an interesting 8-bit structure where repeated initial patterns can be seen.
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Fig. 2
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The longest segment has an interesting structure. In my opinion, the initial part is formed of a 118-bit initial sequence followed by a block consisting of a 192-bit (24 bytes) sequence which is four times repeated; probably it's the synch + initialization vector section of the message.
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Fig. 3
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After the removal of the initial part, the stream shows a 504-bit period but with several alternate sequences (Fig. 4). The same 8-bit structure is visible after the removal of the polynomial x^5+x^4+x+1 (Fig. 5 ). Most likely it's a Chinese waveform, although there are not more informations about it. Recently these transmissions have also been listened on the Twente websdr (and just on the same frequency).
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Fig. 4
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Fig. 5
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https://yadi.sk/d/nECimsqDQuy1hw
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