Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz

[Paul Nicholson <vlf0403@abelian.org>]

Went to investigate why phase at Cumiana was all over the
place and found a mistake.  A pesky command line option
which reported a relative phase instead of absolute.
Also fixed a sign error which reverse all the phases.

All results recalculated below.

Each test is normalised by its RMS value before summing.
S/N dB in 2500 Hz.  Eb/N0 in dB.

Todmorden 881.8 km
------------------

 Daytime 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

 Nightime test   Eb/N0   S/N   Phase  RMS
 15th Nov      -3.0    -67.8  106.5  5.09   no decode
 16th Nov       0.0    -65.5  118.2  4.77

 15th to 16th   1.8    -63.7  113.0

Todmorden night phase lags day by 26.9 degrees, about half
the lag predicted by LWPC.

Cumiana 507.3 km
----------------

 Daytime 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'

 Nightime 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

 15th + 16th    -1.7   -66.6    3.8        no decode

Cumiana night phase lags day by 30.9 degrees.

We've reached a diminishing return for the daytime tests.
Now another week would be needed to gain 3dB.

--
Paul Nicholson
--