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

[Paul Nicholson <vlf0403@abelian.org>]

Cumiana E-field rx vlf15 run by Renato, range 507.3km.

S/N in 2500 Hz, no symbol normalisation used.

             Eb/N0   S/N   Phase
 2016-11-11  -1.7   -66.6   52.1    no decode
 2016-11-12  -3.7   -68.6 -110.2    no decode
 2016-11-13  -7.2   -72.1   28.0    no decode
 2016-11-14  -5.2   -70.0   31.1    no decode
 2016-11-15  -5.5   -70.4  -78.9    no decode

Coherent sums (without correction for phase diffs):

                Eb/N0   S/N     Phase
 11th + 12th     -0.1  -64.7    -31.0  decoded 'TEST'
 12th + 14th     -1.4  -66.3    -75.0  no decode
 12th+13th+14th  +0.2  -65.1    -39.9  decoded 'TEST'

So, even if the received phase is unreliable day to day,
we can still sometimes get a useful sum.

--
Paul Nicholson
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