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By chance, Markus DF6NM has just explained his observations on the DCF39 phase jumps  to me (rewarding, tnx!!). But we are not sure yet if they (at DCF) really care for a high-precision carrier frequency. All I can say now is that the phase jump is always a multiple of  25.7xx° (or so), but WHEN these jump's occur I can't say.
With some luck and a bit of "audio preprocessing in the time domain" it may be possible to make a phase plot of DCF39 with all phase jumps removed, one fine day... but more experimentation must be done.

Would a well-known experienced programmer of beautiful user interfaces like to have the sourcecodes ? ;-)
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