Re: VLF: Carrier on 4470.005 Hz!

[Markus Vester <markusvester@aol.com>]

> but Markus alsways seems to use 20000 which will lead to many false decodes if the optimum length would be 9 actually

Yes maybe, but couldn't I just decide a posteriori to ignore any decodes with rank numbers greater than 9? Can a false decode prevent the appearance of a better-ranked correct one?

Best 73,
Markus

-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Di, 22. Aug 2017 10:32
Betreff: Re: VLF: Carrier on 4470.005 Hz!

Hi Paul, VLF,

Am 21.08.2017 18:48, schrieb Paul Nicholson:

> 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.

Hahaa you changed the calculator website now! ;-) I just wanted to reproduce the settings, http://abelian.org/ebnaut/calc.php?sndb=16&snbws=0.000031&snmps=&code=16K21&sp=60&crc=6&nc=5&submit=Calculate
and now i saw other values and two lines describing the optimum list length more detailed. That is helpful.
In my EbNaut decode attempts i used a larger list length than recommended in the past but Markus alsways seems to use 20000 which will lead to many false decodes if the optimum length would be 9 actually. This can be problematic when using 2...3 characters.

All right now.

Am 21.08.2017 22:15, schrieb Paul Nicholson:

Two days stacked, 20th+21st 07:00 to 19:00.

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

12.5 dB in 23.1 uHz, a little over 4 sigma.

Wow, that peak is so nice and sharp that i decided to run the carrier for another day so you can stack 3 days. The EbNaut message will then start tomorrow 04:00:00.3 UTC.


73, Stefan