Re: VLF: EbNaut tonite, 'SMS' via VLF

[Markus Vester <markusvester@aol.com>]

The transmission was recorded at DL0AO using a synthetic cardioid antenna. Unfortunately my laptop with 8 GB RAM ran out of memory after starting the decoder. If someone with a bigger machine would like to help out, here's our wav:
http://df6nm.bplaced.net/VLF/fec_tests/dl0ao_05250424.wav  (129 kB)

Best 73,
Markus (DF6NM)


-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Do, 25. Mai 2017 22:33
Betreff: Re: VLF: EbNaut tonite, 'SMS' via VLF

Hi Paul, VLF,

That's amazing! A 'SMS' via VLF over ~ 25 wavelengths distance on the 36
km band, from a fixed antenna, in less than a day and without stacking!
Again i think back to 2010 :-)
Such a result in late May! We used to say that VLF won't work in summer,
because of the high QRN levels...
I'm impressed!

73, Stefan

Am 25.05.2017 21:50, schrieb Paul Nicholson:
>
> Stefan wrote:
>
> > Well, let's try something for the record list again:
>
> > f = 8270.100000 Hz
> > Start time: 24.May.2017 20:00:00 UTC
> > Symbol period: 10 s
> > Characters: 160 ( 1 SMS length :-) )
> > CRC bits: 10
> > Coding 8K21A
> > Duration: 22h
>
> Copied
>
> "THIS IS THE FIRST SMS SENT OVER VLF BY RADIO AMATEURS.
> THANKS TO PAUL NICHOLSON, DL4YHF AND DF6NM FOR SOFTWARE
> DEVELOPMENTS. JOIN IN THE EXPERIMENTS! 73, DK7FC"
>
> Rank 0, constant reference phase;
> Eb/N0 = +0.6 dB;
> BER 27.3%;
> carrier S/N: 30.17 dB in 12.6 uHz,
> -18.81 dB in 1Hz,
> -52.79 dB in 2.5kHz;
>
> That's a new record message length for VLF.
>
> --
> Paul Nicholson
> --
>