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

[Paul Nicholson <vlf0403@abelian.org>]

Stefan wrote:

> Message 22.05.2016: 'cqcq dk7fc in jn49ik'

18.22 dB in 4.06 uHz,

 http://abelian.org/vlf/tmp/160604a.gif

which gives Eb/N0 = -2.35 dB on the 20 char message

> Message 25.05.2016: 'not very easy'

16.24 dB in 7.97 uHz,

 http://abelian.org/vlf/tmp/160604b.gif

and Eb/N0 = -2.46 dB.

Seems we are close with both messages, just needs another dB
to have a chance of decoding and another 2dB would make
decode very likely.

These must be amongst the narrowest bandwidth detections anyone
has used.   The day/night phase shift doesn't seem to be causing
us any problem.   But, I wonder if I could gain another dB by
adjusting for a nominal diurnal.   I can use these recordings to
try that.

--
Paul Nicholson
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