On Sat, 2 Mar 2019, DK7FC wrote:
I've tried a lot of antenna mixing but did not get better spectrum peaks that
10.5 dB SNR, so it is quite weak. Best decoder result was 'AV' at rank 70.
The transmitted message was: SP
I'm waiting for your detailed description of the experiment. What antenna and
power was used? How did you generate signal?
A preliminary descritpion is here:
https://klubnl.pl/wpr/en/index.php/2019/03/03/nadawcze-proby-z-dipolem-ziemnym-w-zakresie-vlf/
Around 100W into a 500m long earth dipole, the signal was weak and we were
surprised to have Paul receive it (well, maybe not that surprised given
Paul's excellent receiver).
For the 8270.005Hz carrier we used a GPS generator module (i think it
might be just an uBlox GPS inside, but didn't investigate it). I think
Marcin bought it on some auction site.
For 8270.00073Hz we used an old Neoware terminal with an uBlox neo-7M GPS
installed inside. The gps is used to provide a coarse time reference (not
the best precision because the 1PPS signal is not used), and as a 20kHz
reference signal connected to the terminal sound card. The terminal runs a
slightly modified version of Paul's ebsynth, and some custom-written
software to control the gps. This is the same generator that i've used in
my other tests. I can publish some details in case anyone is interested.
VY 73
Jacek / SQ5BPF
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