Date: Tue, 24 Nov 2015 18:56:29 -0330 (NST)
From: jcraig@mun.ca
To: rsgb_lf_group@blacksheep.org
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References: <5654DE7F.5020404@abelian.org> <8D2F51C6D04B60C-1D98-175C8@webmail-vm016.sysops.aol.com>
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Subject: Re: LF: EbNaut and The Cat / Take 3
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The timing is off by a few seconds: the 2200 sequence ended at 22:20:19.
I think the old antenna is several dB down and that isn't helping things.

Oh well, at least the message arrived! It was very much a joint effort.

73
Joe

On Tue, 24 Nov 2015, Markus Vester wrote:

>
> And any=C2=A0proper test will sometimes fail ;-) No success here on the=
=C2=A021:30 transmission, only a couple of bogus decodes with very high ran=
k numbers. The signal is competely invisible now, and to make thnigs worse =
DCF39 has gone into=C2=A0another hyperactive period, splattering all over t=
he band. Will keep trying...
> =C2=A0
> 73, Markus
> =C2=A0
>
>
> -----Urspr=C3=BCngliche Mitteilung-----
> Von: Paul Nicholson &lt;vlf0403@abelian.org&gt;
> An: rsgb_lf_group &lt;rsgb_lf_group@blacksheep.org&gt;
> Verschickt: Di, 24 Nov 2015 11:04 pm
> Betreff: Re: LF: EbNaut and The Cat / Take 3
>
> Domenico wrote:
>
> &gt; a little signal, but decoded also here
>
> Excellent result.   That's the sort of test I like to
> see, where Eb/N0 =3D 0.7 dB and the program will have
> had to search for the phase and it had to use some
> list decoding.   That's a proper weak signal test.
> I guess it should stand another dB weaker.
>
> The 21:30 just decoded here with Eb/N0 =3D -0.6 dB and
> the phase pattern was -30  -60  -30  -60, might be
> propagation or my timing system having a hiatus.
>
> The symbol timing of the 21:00 looked good.  I tried
> some time shifts both ways and it didn't improve.
>
> Markus wrote:
>
> &gt; It seems that non-existing symbols with null
> &gt; amplitude are not being counted as symbol
> &gt; errors, which severely biases the error rate.
>
> Yes it looks like you're right, the zero symbols are
> not counting as errors.  They contribute neither positive
> or negative to the accumulated log-likelihood of the
> path metric.  It's effectively an erasure code.  I'll
> alter the BER arithmetic tomorrow, it probably should
> consider only the non-zero symbols.  Might need some
> thought.
>
> Have to go out now but the rx continues recording.
> --=20
> Paul Nicholson
> --=C2=A0
> =C2=A0
> =C2=A0
> =C2=A0
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