Re: VLF: Carrier on 4470.005 Hz!

[Paul Nicholson <vlf0403@abelian.org>]

Markus wrote:

> wonder if my little carrier might have contributed
> some energy to the leftmost bin?

Nothing showing above noise, 13:10 to 22:00

 http://abelian.org/vlf/tmp/170821a.gif

Stefan wrote:

> That's already a nice peak!

It looks interesting, although only about 3.5 sigma, needs
a bit more work.

> f = 4470.005000 Hz
> Start time: 22.August.2017  04:00:00 UTC
> Symbol period: 60 s
> Characters: 5
> CRC bits: 6
> Coding 16K21A

With this transmission, the optimum decoder list length will
be about 40 for a full phase search, or about 120 if you
decide the phase is constant enough to restrict the search
to uniform phases.    The chance of successful decode will
then be about 60% at Eb/N0 of -1.0 dB.

It doesn't do any harm to use a longer list than optimum, but
there is no further coding gain.

--
Paul Nicholson
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