From: =?UTF-8?Q?Horst_St=C3=B6cker?= <horst.stoecker@web.de>
Date: Tue, 9 Mar 2010 10:15:58 +0100 (CET)
Message-ID: <31711175.2399083.1268126158633.JavaMail.fmail@mwmweb080>
To: rsgb_lf_group@blacksheep.org
MIME-Version: 1.0
In-Reply-To: <E02A0527-F4FE-4995-A845-73FD5890CAF9@hurontel.on.ca>
References: <E02A0527-F4FE-4995-A845-73FD5890CAF9@hurontel.on.ca>
Importance: normal
Sensitivity: Normal
Subject: Re: LF: Through-The- Earth Communication
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org


Hello,

- Earth Current Communications - by G0AKN was the first article I read abo=
ut 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 di=
rectly on the earth and the copper rods are about 60cm each. The relativel=
y wet ground is probably not the best environment for an earth base antenn=
a..

For the - audible range - including <9kHz I can easily reproduce Johns 200=
m 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 electro=
des 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 bas=
e.

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 wit=
hout different transformers. But at the moment still snow and temperatures=
 below zero keep me aware from building and optimizing my antennas. So als=
o the <9kHz experiments stopped.=20

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 no=
t 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. Ju=
st for fun . . .

In the web I found some further articles on earth antennas / ground antenn=
as beside the one bu G0AKN and the mentioned above by journal of communica=
tions,

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 ante=
nnas.

vy73 Horst DO1KHS


-----Urspr=C3=BCngliche Nachricht-----
Von: John Bruce McCreath <weazle@hurontel.on.ca>
Gesendet: 08.03.2010 21:35:02
An: rsgb_lf_group@blacksheep.org
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 communicatio=
ns.
>
>73, J.B., VE3EAR
>
>LowFER Beacon "EAR"
>188.830 kHz. QRSS30
>
>
>
>
>
>
___________________________________________________________
GRATIS f=C3=BCr alle WEB.DE-Nutzer: Die maxdome Movie-FLAT!
Jetzt freischalten unter http://movieflat.web.de