Re: LF: VLF Carrier on 8270.01 Hz from a ground loop antenna - The 6th station on Paul's spectrogram

[Markus Vester <markusvester@aol.com>]

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 <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
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 <selberdenken@posteo.de>
>> Reply-To: rsgb_lf_group@blacksheep.org
>> To: rsgb_lf_group@blacksheep.org
>> 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!!!!
>>