Re: VLF: 8270: now 8269.990Hz

["Markus Vester" <markusvester@aol.com>]

The notion of correlated noise leading to identical false decodes is intriguing. But with our receivers being five wavelengths apart, a spatially distributed noise source (like a thunderstorm) would need to be spatially confined to preserve phase coherence between receivers (approximately within 6 degrees when looking broadside towards north/south, somewhat wider to east-west). A Blitzortung.org map showed only few lightning events in Europe between 22:00 and 2:30, but the background may well have been dominated by distant storms in South America.

 

I have uploaded the wavs from Stefan and myself (along with other data) to http://df6nm.bplaced.net/VLF/fec_tests/dj8wx_160331-0401/ (note that our wavs have slightly different samplerates and start times so resampling would be required before attempting correlation).

 

Suspiciously this happened with a transmission starting April 1st, 0:00 local time. Wondering if Paul might have hidden an Easter egg in Ebnaut for Windows ;-)

 

Still got no visible carrier here from Uwe this afternoon. The 16 UT message produced "PU" with 2.4 dB symbol / 0.2 dB carrier Eb/N0, again not very trustworthy - I wonder what Stefan got this time...

 

Best 73,

Markus (DF6NM)

 

From: Markus Vester

Sent: Friday, April 01, 2016 4:23 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: VLF: 8270: now 8269.990Hz

GL, really? Very strange. Synchronous noise all over Germany?

 

73, Markus

 

-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 1 Apr 2016 3:42 pm
Betreff: Re: VLF: 8270: now 8269.990Hz

Hello Uwe,

Well, i'm also getting the message "GL" :-) Are you sure it was not GL? ;-)
No other decodes. Sorry.
But we will make it soon, the situation is always improving.

73, Stefan

Am 01.04.2016 13:04, schrieb uwe-jannsen@kabelmail.de:

Markus,
first:         the decode is wrong
second: same procedure today, start of message 16:00:00
third:       pse try the decoder with redundency check (V0.4b)

73
Uwe
PS. the carrier is on the air

 

Von: Markus Vester <markusvester@aol.com>
Gesendet: 01.04.2016 12:04
An: <rsgb_lf_group@blacksheep.org>
Betreff: Re: VLF: 8270: now 8269.990Hz

 

Hi Uwe,

 

unfortunately static level was high, preventing your carriers before and after the PSK from showing up in my spectrogram. The EbNaut decoder produced "GL" at rank 13429 and -1 dB Eb/N0, but I have no clue whether this message is really correct.

 

Best 73,

Markus