Hi Paul,
Thanks for the daily details and the summary. We or at least i learned a
lot from the tests.
Probably there would have been a night decode in cumiana if the stream
would have been available last night.
The night phase between us (Todmorden - Heidelberg) seems to be quite
stable as well. In average it is about 6 dB weaker. So we need 4 times
longer to get the same SNR.
Would it makes sense, when we try the longest VLF message ever (it must
be 75 characters, i found an important message! :-) ), to run day and
night transmissions? When you assume a known day/night phase shift (28.8
deg) you could correct that and then add the night signals to the day
signals. 4 days night+day would then be as good as 5 days day-only, in
principle. Could be worth to try if there is no result after 4 days.
Since the day/night phase offset is almost constant, does it mean that
the groundwave phase and the skywave phase is constant as well? Could
be assumed from a constant refelction height at night (90km) but i did
not think that it is so easy.
If night is 6 dB worse than day (simplified perception), is it just due
to the higher QRN levels or is there some kind of destructive
interference between skywave and groundwave? If so, this could be
different on a QTH beeing a few 10 km distant.
Just some thoughts...
What about all the other stations out there, RX and/or TX? Are we alone
now with our special stuff?
73, Stefan
Am 18.11.2016 18:40, schrieb Paul Nicholson:
Stefan wrote:
> 6 UTC, a carrier starts on 6470.005 Hz, taking 48 hours.
http://abelian.org/vlf/tmp/161118a.gif
S/N averaging -68.5 dB in 2500Hz, noisier than recent
daytime tests. Snowing much of the day here and lots of
noise on the E-field antenna.
> A test for RN3AUS and IK1QFK and all those taking part in
> the background.
LWPC predicts the signal in Moscow to be around 48dB below
1uV/m, 3dB stronger at night. Long overland path, over 2000km
so plenty of attenuation.
Cumiana lost its internet connection last night so no final
overnight 'TEST' result from there. Back on since 14:33 today.
Final results of the 'TEST' messages.
Todmorden 881.8 km
------------------
Day test Eb/N0 S/N Phase RMS
2016-11-11 3.9 -62.5 141.2 2.56
2016-11-12 4.9 -59.7 134.3 2.01
2016-11-13 8.5 -55.6 138.5 1.07
2016-11-14 3.5 -61.3 136.8 2.48
2016-11-15 1.1 -64.0 139.9 3.59
2016-11-16 5.0 -60.8 140.8 2.45
2016-11-17 3.4 -61.6 152.3 2.87
11th to 12th 7.5 -57.9 137.1
11th to 13th 9.6 -53.8 137.8
11th to 14th 10.4 -53.1 137.6
11th to 15th 10.7 -52.9 137.8
11th to 16th 11.8 -52.3 138.3
11th to 17th 11.8 -51.9 139.9
Night test Eb/N0 S/N Phase RMS
2016-11-15 -3.0 -67.8 106.5 5.09 no decode
2016-11-16 0.0 -65.5 118.2 4.77 'TEST
2016-11-17 -4.1 -69.0 105.8 7.13 no decode
15th to 16th 1.8 -63.7 113.0 'TEST'
15th to 17th 2.5 -62.6 111.1 'TEST'
Todmorden night phase lags day by 28.8 degrees.
Cumiana 507.3 km
----------------
Day test Eb/N0 S/N Phase RMS
2016-11-11 -1.7 -66.6 21.9 3.90 no decode
2016-11-12 -3.7 -68.6 41.3 4.32 no decode
2016-11-13 -7.2 -72.1 51.0 3.81 no decode
2016-11-14 -5.2 -70.0 39.2 4.28 no decode
2016-11-15 -5.5 -70.4 39.3 6.23 no decode
2016-11-16 -0.4 -65.3 31.4 4.78 no decode
2016-11-17 -2.3 -67.1 30.1 4.94 no decode
11th + 12th 0.8 -64.6 30.4 decoded 'TEST'
11th to 15th 2.9 -62.5 36.6 decoded 'TEST'
11th to 16th 4.6 -60.8 34.3 decoded 'TEST'
11th to 17th 4.9 -59.8 34.7 decoded 'TEST'
Night test Eb/N0 S/N Phase RMS
2016-11-15 -5.0 -69.8 2.5 9.88 no decode
2016-11-16 -4.5 -69.3 5.1 9.06 no decode
2016-11-17 no recording
15th + 16th -1.7 -66.6 3.8 no decode
Cumiana night phase lags day by 30.9 degrees.
--
Paul Nicholson
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