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Date: Sun, 30 Oct 2016 21:29:13 +0100
From: DK7FC <selberdenken@posteo.de>
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Subject: Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz
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Hi Paul,

Thanks for the efforts and feedback.
So far the best result is 10 characters with 100s symbols 8K19A, that 
was in May.
Its strange that the 3 char message didn't decode with 60s symbols!

Now its nearly November. Perhaps its a good idea to try to get shorter 
messages through, just to see how the SNR will look.
I could start in the morning hours, 3 characters at first.
So be prepared! :-)

73, Stefan


Am 27.10.2016 21:10, schrieb Paul Nicholson:
>
> Recent transmissions from Stefan
>
>  2016-10-05_21:00:02,+138880 6470.0 S140 C15 8K19A
>  2016-10-07_21:00:02,+166400 6470.0 S80 C15 16K25A
>
>  2016-10-10_14,+29h 6470.0025 carrier
>
>  2016-10-12_14:30:00,+16640 6470.0 S40 C3 8K19A
>  2016-10-13_06:00:00,+41600 6470.0 S20 C15 16K25A
>  2016-10-14_13:15:00,+24960 6470.0 S60 C3 8K19A
>
> Sadly, unable to decode any of the EbNaut messages
> although 2016-10-07_21:00:02,+166400 looked close
> with a couple of partial decodes:
>
>         'DK7FC4R,3ZSB35X'  Eb/N0 = -0.4dB
>         'DK7FC4273 U8Z  '  Eb/N0 = -1.1dB
>
> The carrier has been useful and I managed to gain
> nearly a dB using it to play with blanker settings,
> E-field mix and loop pointing.  E-field mix is
> fiddly, amplitude depends on the weather!
>
> Using the carrier (which decodes to **** messages)
> I obtained the following all-star decodes from
> the 06:00 to 18:00 signal,
>
>         16K25A S30 C8  Eb/N0 = +2.3 dB ber 37.1%
>         16K25A S25 C11 Eb/N0 = +1.2 dB ber 37.8%
>         16K25A S20 C15 Eb/N0 = -1.0 dB ber 40.0%
>
>          8K19A S60 C9  Eb/N0 = +0.9 dB ber 33.8%
>          8K19A S45 C14 Eb/N0 =  0.0 dB ber 34.1%
>          8K19A S40 C15 no decode
>
> I continue to think that the best prospect for a 15 char
> success is the 12 hour daytime signal with 16K25A 20
> second symbols.  It might take a couple of attempts.
>
> We seem to struggle with transmissions that use both
> day and night.  I've tried compensating for the extra
> ~60 degree nighttime phase lag but that didn't help.
>
> I'm running some trials with 24 hours of the carrier
> to see what can be done.   I've also been playing
> with a suggestion that Markus made some time ago to
> normalise the day/night amplitudes in various ways.
>
> -- 
> Paul Nicholson
> -- 
>