Paul receives anything (as usual). But the strange thing is that i can
receive the 6470Hz signal with a mediocre setup (suboptimal antenna, qrm
location in the center of Warsaw) at 900km, while Eddie (at 750km
distance) and especially Markus (at 180km) can't receive.
The only other explanation (apart from lower qrm levels) might be the
software used. I use Paul's vlfrx-tools, while Eddie and Markus use
Spectrum Lab. The obvious differences are:
- gps timing (edge in speclab vs "stretched pulse" magic in
vlfrx-tools). not sure what impact this may have
- noise blanker. most speclab setups use the noiseblanker on the whole
spectrum (haven't seen your setup, but this is what most example
configrations i've seen do), while the vlfrx-tools/ebnaut examples use the
noiseblanker only on a 3kHz bandwidth segment centered around the rx
frequency (this could be done with speclab easily too). also the speclab
noiseblanker algorithm might be a bit different
Maybe try vlfrx-tools and see if there is any difference? And if so,
tweak speclab to do the same (especially the filtering/noiseblanker
should be simple)
VY 73
Jacek / SQ5BPF
On Mon, 24 Apr 2017, DK7FC wrote:
Date: Mon, 24 Apr 2017 15:18:45 +0200
From: DK7FC <[email protected]>
Reply-To: [email protected]
To: [email protected]
Subject: Re: LF: Re[2]: VLF: New carrier on 6470.005 Hz
Hello Markus, Eddie, Paul,
Thanks for the feedback, for trying and for the results.
Very strange. Paul has excellent results (as usual) but no decode for Eddie. On
8270 Hz, the 'difference' is much less expressed. Does it have to do with local
QRM only? Maybe...
Maybe Alex has detected something.
Pauls results are particularly interesting. 1+1 = 1 * 2 = 3 dB. Proves the
theory
:-)
The stacking would help to solve the problems it seems :-) A tool is needed...
73, Stefan
Am 23.04.2017 23:24, schrieb Markus Vester:
Hi Stefan,
I tried to receive your message on both days, and even added the two
recordings with equal weight, but unfortunately no decode. Guess I need a
railway strike :-(
Unfortunately no luck from DL0AO data either.
Best 73,
Markus
-----Ursprüngliche Mitteilung-----
Von: DK7FC <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: So, 23. Apr 2017 0:42
Betreff: Re: LF: Re[2]: VLF: New carrier on 6470.005 Hz
Hi VLF,
another chance, the same msssage two hours earlier, improved timing towards
the east...
f = 6470.100000 Hz
Start time: 23.Apr.2017 05:00:00 UTC
Symbol period: 40 s
Characters: 2
CRC bits: 32
Coding 16K21A
Duration: 11h, 22m, 40s
Antenna current: 460 mA
73, Stefan
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