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Re: VLF: A message from W4DEX

To: [email protected]
Subject: Re: VLF: A message from W4DEX
From: Lawrence Galea <[email protected]>
Date: Mon, 25 Dec 2017 12:11:28 +0100
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Merry Christmas and a Happy New Year to all from Lawrence 9H1AV

On 12/25/17, Paul Nicholson <[email protected]> wrote:
>
>  > another big step since New Year 2015.
>
> We can always count on Dex to try to push the limits out
> further.
>
> Last night the noise was low, so low that the best S/N
> was bearing 290.  Dex on 284.6.  Usually the S/N
> peaks up by aiming off at 310 to 330.
>
> It was also the first time I used the new antenna
> calibrations to mix the signal for a decode.
>
> We used 8269 to avoid any overlap with VO1NA.
>
> Given those conditions, we could have tried 42 chars,
> 16K25A CRC16 with 7 second symbols 23:00 to 08:05:04,
> for Eb/N0 -0.15.
>
> Correlations from on-line receivers (a loss of
> perhaps 1 to 2dB due to vorbis encoding):
>
>   Bielefeld 6918 km, Eb/N0 -12.3 dB;
>   Cumiana   7173 km, Eb/N0 -10.0 dB;
>   Warsaw    7681 km, Eb/N0 -19.7 dB;
>   Forest VA  254 km, Eb/N0 -1.2 dB *Decoded* rank 0;
>   Hawley TX 1816 km, Eb/N0 -7.7 dB;
>
> The low Eb/N0 at Forest is surprising.  Something is wrong,
> should be a huge signal. In 2015 Dex's EbNaut was even
> visible on a spectrogram at Forest.
>
> What do normal people do on Christmas day morning? I was
> out at the H rx site with a spectrum analyser looking at
> the amplitude of some MF signals (909kHz 5mV RMS on the
> open circuit loop).
>
> Meanwhile, I'm running low on celebratory cigars!
>
> --
> Paul Nicholson
> --
>
>

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