Re: VLF: 300 mA on 4470 Hz, 67 km band

[Markus Vester <markusvester@aol.com>]

Again a good decode from Amberg as well. Unfortunately 16K23A appears to be close to the limit of my 4 GB machine, the decoder is progressing very slowly.

Knowing the message, I can now set up the unspreading sequence for the 424 uHz phase graph on the DL0AO grabber.

Best 73,
Markus (DF6NM)



-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 19. Jan 2018 9:28
Betreff: Re: VLF: 300 mA on 4470 Hz, 67 km band

Stefan wrote:

> f = 4470.100000 Hz
> Start time: 18.JAN.2018 16:00:00 UTC
> Symbol period: 60 s
> Characters: 2
> CRC bits: 16
> Coding 16K23A (NEW)
> Duration: 13h20min [hh:mm]
> Antenna current: 300 mA

> Unintentionally the message was sent with 30 second
> symbols this night.

Good copy in Todmorden. Based on last night's carrier,
the signal calculated predicted Eb/N0 would be +3.5 dB,
and I got a decode at +3.8 dB.

A distance record for message decode at the 67km band.

Bielefeld: Eb/N0 +13dB, *Decoded*

Warsaw: Eb/N0 -10.7 dB;

Cumiana: Eb/N0 +5.0 dB *Decoded*

First message decode Germany to Italy at this band.

A nice result for first use of 16K23A. Decoder needs 3.5 Gbyte
RAM for this message size with optimum list length.

--
Paul Nicholson
--

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