Yeah maybe. But at the moment I'd rather keep
things as simple as possible, and I anyway wouldn't expect a sharp optimum
regarding speed.
The idea is to compare the SNR of the slow sequence
with the average of the two surrounding fast sequences, received by the
same monitor. If the dB results were the same, we could probably exploit
the full 9 dB advantage due to the lower threshold (-38 vs -29 dB), otherwise
we'd have to subtract the dB difference.
Results from first round:
2015-05-30 23:46
DF6NM 0.475791 -11 0
JN59nj 0.5 DL4YHF JO42fd
359 330 2015-05-30 23:30
DF6NM 0.475824 -8 0
JN59nj 0.5 DL4YHF JO42fd
359 330 2015-05-30 23:28
DF6NM 0.475791 -11 0
JN59nj 0.5 DL4YHF JO42fd
359 330
=> WSPR-15 SNR happened
to be 3 dB better!
2015-05-30 23:46
DF6NM 0.475790 -15 0
JN59nj 0.5 SM2DJK KP03au
1694 15 2015-05-30 23:30 DF6NM
0.475823 -13 0 JN59nj
0.5 SM2DJK KP03au 1694 15
2015-05-30 23:28
DF6NM 0.475790 -14 0
JN59nj 0.5 SM2DJK KP03au
1694 15
=> WSPR-15 shows 1.5 dB
better.
2015-05-30 23:46 DF6NM 0.475792
+1 0 JN59nj 0.5
DG3LV JO53gv 502 356
2015-05-30 23:30 DF6NM 0.475824
-2 0 JN59nj 0.5
DG3LV JO53gv 502 356
2015-05-30 23:28 DF6NM 0.475792
-8 0 JN59nj 0.5
DG3LV JO53gv 502 356
=> WSPR-15 shows 1.5 dB
better.
This is an unexpected result, implying that the advantage of WSPR-15
would be more than 9 dB, instead of less. But on the other hand the dB
values may not be telling the whole story, because the threshold for a
fading signal might still be higher than -38 dB.
All the best,
Markus (DF6NM)
Sent: Sunday, May 31, 2015 1:33 AM
Subject: Re: LF: Dual-speed WSPR
Markus,
What
about the old slow-WSPR by DF6NM? It could be useful to try WSPR-4 for
experiments. There is not just 2 and 15. And WSPR-120 on VLF... No
problem!
73, Stefan
Am 31.05.2015 01:28, schrieb Markus Vester:
To allow SNR comparisons at different speeds, I
will transmit a mixed-mode beacon tonight. It will consist of two WSPR-2
sequences, before and after a WSPR-15 sequence on each odd half
hour:
hh:28 - hh:30: WSPR-2 475.790
kHz hh:30 - hh:45: WSPR-15 475.823 kHz
hh:46 - hh:48: WSPR-2 475.790
kHz
Transmitter power is currently 25 watts into an antenna with 2%
efficiency. Am listening to both modes at all other times.
All the best,
Markus (DF6NM)
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