Message-ID: <4CA250E0.9010909@iup.uni-heidelberg.de>
Date: Tue, 28 Sep 2010 22:32:32 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: Loops on TX
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Hi Scott,

Yes. The more rocks the better the result. The lower the ground 
conductance, the deeper the flow back current and thus the larger the 
loop area. Near my hill/mountain (is 520 m ASL a hill or a mointain if 
the sourrounding region is about 120 m ASL?) there is a stone pit 
(http://maps.google.de/maps?ll=49.456911,8.681259&spn=0,0.027423&t=h&z=15&lci=com.panoramio.all&layer=c&cbll=49.456911,8.681259&cbp=12,0,,0,5&photoid=po-23608032). 
I cannot hit a earth rod more than 0.4 m into the soil since there is 
the stone!
This makes more effort on the earth rod site but all in all the stone is 
a big advantage is think!

BTW, you do not need a big wire! The losses are dominated by your ground 
resistance, not by the wire resistance. So you can use 1 mm diameter or 
less. This makes it easy and cheap. Telephone drop wire is a very good 
choice. The longer the wire the better! Voltages are moderate and 
currents as well, depending of power and ground losses of course :-)

I will keep you informed about my progress on improving this antenna (soon).

73, Stefan/DK7FC

Am 28.09.2010 02:47, schrieb Scott Tilley:
>  Hi Stefan and Group
>
> The topic of Earth antennas is interesting.  My question is how well 
> will one work over rock?  I really have little or no soil here.  Any 
> experience with this situation?
>
> I do have a 100m deep well into the rock down to an aquifer.  Perhaps 
> that for one end and the other???
>
> Any experience in this area out there?
>
> TU Scott
>
>
>> Scott, don't you want to give VLF a chance? If you have so much space 
>> (like i have too in the Heidelberg's forest, but not as close to my 
>> home QTH), you could try to build a (earth) loop of some 10000 m^2 
>> and could start a canadian VLF experiment!? I would watch out for 
>> your signal! :-)
>>