Hi Markus, VLF,
Thanks for mentioning the 8270.0027 Hz traces at DL0AO. I've been watching
closely ever since. There appear to be dirunal frequency shifts on
this signal (or perhaps it is my imagination).
There are guard rails here that run in a straight line for about a km
that would make fine ground loops for VLF but getting across the pond
might be challenging.
73
Jor VO1NA
necy
shifts
On Sat, 29 Dec 2018, Markus Vester wrote:
Hi Stefan,
a similar "miracle" occured at DL0AO: The trace from your ground loop
appeared very strong on the NS-loop, which should have a null towards your transmitter.
The peak was - 120 dB on EW and V, and -125 dB on NS, only 5 dB difference.
I believe our N-S receive loop is seeing only the skywave component. Due to
the angular orientation of your transmit loop, the electric field of the
upward radiation will be polarized in the NW-SE direction, with the orthogonal
magnetic field pointing NE-SW. This polarization will be more or less retained
during the reflection (possibly rotated a bit by Faraday effect). So the
downgoing wave will also contain a magnetic field component in the E-W
direction, which is then picked up by the NS-loop.
So yes, earth loops are loops.
Best 73,
Markus (DF6NM)
-----Ursprüngliche Mitteilung-----
Von: DK7FC <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: Sa, 29. Dez 2018 19:27
Betreff: Re: LF: VLF Carrier on 8270.01 Hz from a ground loop antenna - The 6th
station on Paul's spectrogram
Hello Jacek,
Oh, indeed, very clear! I did not expect this at all. The loop, if it
behaves as a loop at all (!), points towards Paul. It should have a null
into your direction. Our distance is 976 km !
http://k7fry.com/grid/?qth=KO02MD&from=JN39WI
Why do you see the signal at all? I'm puzzled but it feels good :-)
Tomorrow, maybe i'll do something on 2970.01 Hz!
73, Stefan
Am 29.12.2018 18:25, schrieb Jacek Lipkowski:
Good signal on my grabber:
https://klubnl.pl/wpr/en/index.php/klubnl-pl-grabbers/grabber-4-8270hz/
What is the antenna orientation?
jacek
On Sat, 29 Dec 2018, DK7FC wrote:
Date: Sat, 29 Dec 2018 13:43:14 +0100
From: DK7FC <[email protected]>
Reply-To: [email protected]
To: [email protected]
Subject: LF: VLF Carrier on 8270.01 Hz from a ground loop antenna -
The 6th
station on Paul's spectrogram
Hi VLF friends,
Since 11:35 UTC i'm running about 2.5 A antenna current into my 900m
long ground loop antenna. Frequency is 8270.01 Hz. The signal is very
strong on my own grabber in 57.6 km distance but also at DF6NM, DL0AO
and it looks like there is a peak now on Paul's spectrogram building
up slowly.
I intend to run the carrier for 2 hours or so, until the accu is
almost empty :-)
The H bridge PA voltage is 175 V and the power consumption is 450 W.
Today, the DC measuremant result is 66V for 1 A antenna current. It
is cold and wet!
More soon.
73 de DK7FC/P in JN39WI
PS: The QRN is exceptional low!!!!
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