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Re: VLF: A 300 char message?

To: [email protected]
Subject: Re: VLF: A 300 char message?
From: DK7FC <[email protected]>
Date: Tue, 14 Nov 2017 13:46:28 +0100
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Hi Paul, VLF,

Great! I think this is the longest EbNaut message ever, so far ;-) Thanks for the decode. We needed 3 days but the right 2 days would have been fine as well. Did you try to decode the 3rd on its own? With just a few 1/10 dB less noise we could manage a decode in one night, that's impressive. I could now try to pass you a 1000 character message using ebkey and a relay steered by the Raspi. But i would tend to focus on other goals in the next days, i.e. further attempts with RC4HAA.
Markus, the message is in attachment.

73, Stefan

Am 14.11.2017 12:03, schrieb Paul Nicholson:
Stefan wrote:

> f = 8270.1000 Hz
> Start time: 11.November.2017  17:00:00 UTC
> Symbol period: 6 s
> Characters: 300
> CRC bits: 16
> Coding 4K19A
> Duration: 12:13:36h

> message start delayed by 15 minutes...

Copied

 "HELLO PAUL AND THE REST OF THE LF GROUP! WELL, THIS IS THE NEW
  LONGEST MESSAGE TRANSMITTED ON VLF. THANKS TO ALL  STATIONS WHO
  PARTICIPATE IN THE EXPERIMENTS SINCE 2010! VLF IS A GREAT REAGION
  IN THE RF SPECTRUM. WHO KNOWS WHAT WE WILL DEVELOP AND DISCOVER
  IN THE NEXT TIME :-D  73 DE DK7FC IN JN49IK"

using combined 12th/13th and 13th/14th.

Constant reference phase, Eb/N0 = +1.7 dB, BER 21.4%, list rank 0
S/N -12.40 dB in 1Hz, -46.38 dB in 2.5kHz.

Each night:

 11th/12th  Eb/N0 = -4.4 dB, phase 101.5 deg, -18.50 dB in 1Hz;
 12th/13th  Eb/N0 = -2.0 dB, phase  92.5 deg, -16.07 dB in 1Hz;
 13th/14th  Eb/N0 = -0.6 dB, phase 100.6 deg, -14.73 dB in 1Hz;

Combinations
 11/12 + 12/13: -0.1 dB (no decode up to 6E6 list);
 12/13 + 13/14: +1.7 dB (decodes BER 21.4% rank 0);
 11/12 + 13/14: +0.7 dB (decodes BER 22.6% rank 82);

All three: +2.6 dB;

--
Paul Nicholson
--

Attachment: 300 char 8270.zip
Description: application/compressed

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