Re: VLF: EbNaut transmission on 8270.1 Hz again and again

[Markus Vester <markusvester@aol.com>]

Hi Stefan,

 

aah, yes: The pattern in the spectrogram indeed shows that the little "clown's face" structure is actually being repeated in the last part. So the scheduled re-opening of psk.txt after 24 hours has apparently reset the read pointer to the beginning of the file. Hadn't thought of that....

 

All the best,

Markus

-----Ursprüngliche Mitteilung----- 
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 1 Mai 2016 2:12 am
Betreff: Re: VLF: EbNaut transmission on 8270.1 Hz again and again

Hello Paul, Markus, VLF,

Paul, my congrats to the good result. I think it is not necessary to confirm that the message is correct :-)
So the diurnal phase changes are uncritical on our path? Or could it be extremely different?

Markus, thanks for the note. I stopped the TX manually. I fear the problem was that SpecLab restartet the psk.txt file at 16:00:02 today, i.e. after 24 hours. Periodic actions, you know. That would mean that the last 3 hours were corrupted! Have you already had that thought too? Maybe it would be helpful to cut out the last 3 hours of your data files and try again. And we need to find another solution to run messages taking longer then 24 hours.
I would like to play and see the limits.

73, Stefan


Am 30.04.2016 22:23, schrieb Markus Vester:

Paul, Stefan,

 

great, congratulations both!

 

Strange that according to Stefan's forest grabber the PSK transmission was carrying on long after the scheduled end of sequence (19:01:22 ?).

 

Will now attempt to decode here as well.

 

All the best,

Markus

 

-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 30 Apr 2016 9:23 pm
Betreff: Re: VLF: EbNaut transmission on 8270.1 Hz again and again


Stefan wrote:

> Start: 29.04.2016 16:00:02
> Period: 40
> Length: 45 (!)

I was impatient, with still 5549.6 seconds left
to go I decoded the message easily,

'CQ CQ DREAMERS BAND DE DK7FC IN JN49IK PSE KK'

Carrier S/N: 25.03 dB in 10.3 uHz
Eb/N0 = 0.1dB with constant reference phase. I'll
let the decoder go through a full phase search, it
may find a better decode with a phase pattern that
is closer to the diurnal. Later I'll decode the
full transmission, we should get a better Eb/N0.

That must be one of the longest messages decoded.
Only needed 1.8 GByte RAM so within reach of home
PCs.

... decoder has finished the phase search. No
improvement on the 0.1dB so looks like LWPC is close
to the mark with its phase prediction.

--
Paul Nicholson
--

wald3_160429-30_psk.jpg
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