Hi Edgar,
Thanks for the spectrogram showing JXN nicely! Here i'm watching NWC
but the SNR is much lower, probably due to the strong QRN we still have
in late August...
I'm going to calculate the weighting factors for the stacking based on
the noise amplitude from 18...21 UTC. And obviously it is not necessary
to transmit until 0 UTC, so i will stop an hour earlier from now on.
Your SpecLab settings are fine as they are. There is no advantage from
a shorter and wider FFT. The observed spectrum width currently allows
to display more than 2000 FFT bins centered on the TX frequency,
allowing to display enough noise arround the peak to demonstrate that
the peak is most unlikely a by-chance peak...
Thanks for last nights txt file. We can produce a first stack from the
two days. Last night is weighted by -1.3 dB. The result is attached. We
can already see a peak of 11.3 dB SNR, not unrealistic but still not
significant enough. The spectrum peak produced from the suggestion of
the Excel plot (Start 17:50 UTC, duration 2 hours) is attached as well.
It shows a higher SNR, which depends on the noise floor calculation (0
dB line). I need to work on this but anyway the peak looks good
relative to the noise already.
Another carrier will follow tonite.
73, Stefan
Am 23.08.2018 23:40, schrieb Edgar:
Hi Stefan,
Based on the past two days signal from JXN, would it improve the chance
of detecting the carrier if the "FFT window time (length)" matched the
time when the signal is at maximum?
The FFT length is now 8.847 hours. The period when JXN signal is white
is about 1.5 hours.
The FFT bin width would be wider, and a larger percentage of bins would
have a stronger signal.
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