unid FSK 50Bd/612 bursts

Interesting and unid transmissions consisting of 50Bd/612(600?) FSK bursts heard by me and my friend cryptomaster a few days ago, respectively on 6969.10 KHz and 14353.73 KHz (both CF). The bursts have a duration of 3600 ms and are transmitted with an interval of 1340 ms (Figure 1). 

Fig. 1 - FSK bursts transmission

The bitmap shows an asynchronous 8N1 frame where curiously the start/stop bits appear to be transmitted with reverse polarity than usually used (Figure 2).

Fig. 2 - 8N1 frame

As shown in Figures 3,4 the bursts have the same content, probably some kind of ASCII command. DF's attempts have not produced consistent results, perhaps due to the nature of the transmissions (not continuous).

Fig. 3

 

Fig. 4

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