VLF,
Due to the recent results i'm extending the running experiment:
Start time: 15.11.2016 20:00:00 UTC & 08:00:00 UTC (Daily
repetition)
So there are two of these transmissions per day now.
A night transmission could be interesting as well. We can check the
phase and its stability, relative to the day-transmission. Maybe the
results are better in Italy (after passing the Alps)?
The first night transmission has started a few seconds ago...
73, Stefan
Am 10.11.2016 17:46, schrieb DK7FC:
Hi Paul, VLF,
OK, the QRN is very low!
Let us start a series of experiments. I would like to continue working
on the idea to build an overylay of a few transmissions to rise the SNR
and to lead to a decode by that way. Also i would like to use the 8K19A
mode again just that i am able to decode the message on my own PCs (via
the remote stream from the tree) so i can test if it works. You know
the text files generated by SpecLab contain numbers like "8269.6142
-1.3112E-08 -7.4201E-08 -1.2608E-08 -5.5143E-08 2.7815E-08" and so on.
If i could add them simply by adding the numbers/values i could build
the same overlay, coherently? This is what i want to experiment with.
Also for you, i chose a message with less characters, so you can get a
decode and see the phase pattern. Then you can see how much SNR
improvement you will get when adding the data of two transmissions with
known SNR and you will see (if the start time and length is kept
constant) how the phase varies each day.
So:
f = 6470.00000 Hz
Start time: 11.11.2016 08:00:00 UTC (Daily repetition)
Symbol length: 60 s
Characters: 4
CRC 16
Coding 8K19A
Duration: 7h, 44m, 0s
Antenna current: ~ 280 mA
I hope that will lead to some better understanding of the propagation
on that 46km band and for getting an idea if that coherent adding of
daily transmissions makes sense, and where the limit of the SNR
improvement tends to.
Suggestions welcome.
73, Stefan
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