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From: Gary - G4WGT <g4wgt@tiscali.co.uk>
Message-ID: <56E7090D.4090601@tiscali.co.uk>
Date: Mon, 14 Mar 2016 18:55:09 +0000
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Subject: Re: LF: EbNaut from Todmorden
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Hi Paul & All,

Paul wrote :-
I was about to fire up the tx but it looks like somebody is
on or near 137.465 already.

That was probably Mike G3XDV running Opera "Op32" mode (32 minutes Tx).

See :-

https://www.dropbox.com/s/7t1tuy1iuuglvqj/Screenshot%202016-03-14%2018.41.52.png?dl=0

73, de Gary - G4WGT
                             
MF-LF-VLF Grabber : http://myweb.tiscali.co.uk/wgtaylor/grabber2.html
Web : http://myweb.tiscali.co.uk/wgtaylor/index.html

.

On 13/03/2016 21:34, Paul Nicholson wrote:
>
> Thanks all very much indeed for the reports and decodes.
>
> I've downloaded Domenico's wav files for a closer look.
> It was a good result for EbNaut.  The best decode by Domenico
> corresponds to about -46dB in a 2.5kHz bandwidth and it seems
> that I made a good guess of the symbol period to use.
>
> The phase is clearly a lot steadier at LF than MF.  In almost
> all cases the BER was lower than expected from the measured
> carrier S/N which I think tends to indicate that other signals
> or interference are present in the ebnaut-rx input file but
> outside the bandwidth of the transmission.
>
> It looks like I could have dropped to 24W input and still
> get at least one decode from Markus and Domenico. At a BER
> corresponding to 13dB S/N with the 03:00, the constellation
> is beginning to show some axis and the two phases for a time
> almost separate completely.
>
> I am completely impressed by Reolof's reception capability at
> both LF and MF.  If I connected the multiplier output to the
> antenna I wouldn't be surprised to be received in Middelburg.
>
> It was most unexpected to find that the transmission at LF
> didn't affect the VLF receivers at all.  This enabled me to
> leave the tx on overnight and not miss any of the VLF activity
> that was going on last night.
>
> Before I dismantle the tx and antenna, I'll aim to do another
> run this evening with the signal 10Hz higher to avoid the
> interference Stefan mentioned.  Maybe 22:00 to 00:30.  I only
> wish there were some more distant coherent receivers to aim
> for using longer symbol periods.  It would be nice to know if
> LF could support, say, 8 second symbols for a two hour message
> at very long range.
>
> An unresolved mystery are those periodic glitches showing
> up on Gary's spectrogram.   I'll be having another look at
> those later.
>
> I was about to fire up the tx but it looks like somebody is
> on or near 137.465 already.
>
>  http://myweb.tiscali.co.uk/wgtaylor/grabber2.html
>
> -- 
> Paul Nicholson
> -- 
>