Hello,
- Earth Current Communications - by G0AKN was the first article I read about
this item some years ago. Even actually I have installed an earth base of about
35m - the maximum possible distrance - in my garden. Wire is directly on the
earth and the copper rods are about 60cm each. The relatively wet ground is
probably not the best environment for an earth base antenna..
For the - audible range - including <9kHz I can easily reproduce Johns 200m
even in the urban environment of my house. I also use a portable sferics RX for
that. By tipping the antenna to the ground or using ground electrodes I get
better reception than with the whip antenna just in the air.
The TX signal comes from a sweep generator software. Soundcard to my car audio
PA at about 100 W to a 100V audio transformer feeding the earth base.
As RX-Antenna for 136 kHz it is not too bad.
On 500 kHz it does not really work.
I will add some db scales of the T-antenna and the earth base with and without
different transformers. But at the moment still snow and temperatures below
zero keep me aware from building and optimizing my antennas. So also the <9kHz
experiments stopped.
Absolutely surprising is the fact that even on 80m the earth base worked. I
could manage a local QSO. My signal was much weaker than with the half wave
dipole of course. Even on 160m the SWR was not too bad, but I did not expect
any QSO. Assuming that this antenna is relatively broadband - but lossy too - I
will soon give it a try on other short wave frequencies. Just for fun . . .
In the web I found some further articles on earth antennas / ground antennas
beside the one bu G0AKN and the mentioned above by journal of communications,
http://www.vlf.it/ed/earthprobes.html
http://www.vlf.it/receptiontec1/receptiontec1.htm
here: earth dipole. I am a bit sceptical about the 1:1 audio transformer. The
100V audio transormer should work better.
In german:
http://technik.fuko-kolkwitz.de/html/erdantenne.html
http://www.fuko-kolkwitz.de/Bodenantennen.pdf
http://www.radiomuseum.org/forumdata/users/5100/Funkschau_2jg_1529_1v1_v20.pdf
hier: Untergrundantenne
http://forum.mysnip.de/read.php?8773,512316
I think we should not too much merge the threads <9kHz and earth base antennas.
vy73 Horst DO1KHS
-----Ursprüngliche Nachricht-----
Von: John Bruce McCreath <[email protected]>
Gesendet: 08.03.2010 21:35:02
An: [email protected]
Betreff: LF: Through-The- Earth Communication
>Hello LFers,
>
>I did a Google search using the subject line and found quite a number of sites.
>One of them:
>
>http://www.academypublisher.com
>
>had a very interesting writeup on the subject of ground loop communications.
>
>73, J.B., VE3EAR
>
>LowFER Beacon "EAR"
>188.830 kHz. QRSS30
>
>
>
>
>
>
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