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Date: Wed, 10 Apr 2019 08:59:24 +0200
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org
References: <1652663722.1033558.1554575549616.ref@mail.yahoo.com> <1652663722.1033558.1554575549616@mail.yahoo.com> <5CA90E98.2070707@posteo.de> <8c46744b-f60a-ca91-f60f-97a2f5f7b11f@abelian.org> <5CA931D4.6050908@posteo.de> <83eece37-ae11-b2fd-917c-ad29c350695b@abelian.org> <5CA9BD98.2030002@posteo.de> <alpine.DEB.2.11.1904071231190.22616@mailn.lipkowski.org> <5CAA1D1D.8070204@posteo.de> <alpine.DEB.2.11.1904082241090.22616@mailn.lipkowski.org> <5CABBF99.6010502@posteo.de> <alpine.DEB.2.11.1904090832200.22616@mailn.lipkowski.org>
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Subject: Re: ULF: EbNaut message transmitted from ground loop
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RR Jacek,

I did not get better results than 15.05 dB using
vtread -T2019-04-06_20:25,+125m /jacek | vtcat -p | vtfilter -a th=4 -h 
bp,f=2970,w=3000 | vtfilter -h hp,f=2000,poles=8 -h lp,f=3600,poles=14 | 
vtblank -v -a22 -d0.0005 -t100 | vtmult -f2970.1 | vtresample -r240 | 
vtresample -r10 > msg.vt
Maybe you can get a better result with that command line because your 
data did not pass the vorbis way.

All this is most fascinating. How is it possible that the signal 
propagates over to you, into your direction? If you are still in KO02MD, 
then this is not only a new record distance of 976 km! Also, the bearing 
is 66 deg between us but the antenna points towards 306 deg, so there is 
a 60 deg offset between us. Looks like the loop does NOT behave like a 
loop, at least at night and at that frequency, because there must be a 
loss of 20 lg(cos60) dB = -3 dB into your direction. Also you have E 
field only and live in an urban location whereas Paul is 130 km closer 
and can use E+H fields to optimise the SNR. His SNR is 2 dB better but 
the loop points almost exactly into his direction.
The larger loop has a higher DC (and AC) resistance, so the TX power was 
not as high as it could have been. I remember how i discussed with 
Markus on the phone, while TXing, that this may cost 0.5 dB of SNR. This 
0.5 dB could have made the success between us! :-)

So, if the loop does not behave like a loop (actually the system loop + 
propagation path) at night and at that frequency, then we miss the 
expected gain from a loop at a location that should profit from it. But 
on the other side we have the chance to detect the signal into a certain 
range anywhere. How far will that work?


73, Stefan


Am 09.04.2019 22:02, schrieb Jacek Lipkowski:
> On Mon, 8 Apr 2019, DK7FC wrote:
>
>> Did you use your large computer at work to try to get the best result?
>
> no, unfortunately i had to give it back. but i did a simple search 
> over a small set of parameters (a few hundred  -a , -t and -d 
> combinations, and some tests with different filtering).
>
> jacek
>