Hello friends,
Dick, WA3USG had send me a file of a recording he has made in the US and
what he thinks might be DCF39,
I have made a first very preliminary analysis tonight. The file contains a
carrier on 700 Hz which can clearly be seen on Spectrogram 5.1.6 ( and also
can clearly be heard through the noise.
I found the following inconistencies in that carrier:
11595 ms - 12089 ms (length 496 ms)
25605 ms - 26289 ms (length 684 ms)
time in between 13516 ms.
In the second half of the file the noise was too strong and the AGC of
Dick's receiver pulled the signal down, so that reading here were not that
clear.
My first very cautious analysis would be to assume, that those
inconsistencies in the carrier might be the data bursts of DCF39. Data of
these bursts vary, the recording I had on hand showed values for the length
of the data burst between 876 ms and 883 ms and the time in between two
bursts 11488 to 13500 ms.
What I need, if possible, is a longer recording (5 to 10 minutes) with AGC
off. Additionally, it would help to have a similar recording of the data
frequency of the FSK signal on 139.170 kHz.
Best 73
Geri, DK8KW (W1KW)
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