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To: rsgb_lf_group@blacksheep.org
Subject: RE: LF: Ground loss
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From: "john sexton" <computernetworks@excite.com>
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 Hi Sasha,
<br />
Are you sure that you have written the formula correctly?
<br />

<br />
Omega (2 Pi f) appears in "a" in the numerator and in "Xc" in the denominator and therefore cancels out, making the formula frequency independent!
<br />

<br />
Perhaps there is a typo??
<br />

<br />
73, John, G4CNN
<br />

<br />

<br />
--- On Tue 05/14, Alexander S. Yurkov <fitec@omskcity.com> wrote:
<br />
> 
<br />
> Hi LF Group
<br />
> 
<br />
> > On Sat, 23 Mar 2002, john sexton wrote:
<br />
> > If you do find a model that works, please let us know.
<br />
> 
<br />
> 
<br />
> On the base of my own "generalased mirror reflection theory" I
<br />
> just have
<br />
> derive the formula for ground loss resistance:
<br />
> 
<br />
> 
<br />
> R = (lant/lcp)*a*Xc
<br />
> 
<br />
> where:
<br />
> 
<br />
> lant - wire length of antenna,
<br />
> lcp  - wire length of ground system (conterpoint),
<br />
> a = (eps0*w)/s,
<br />
> eps0 - dielectric constant (8.85e-12 F/m),
<br />
> w = 6.28*f - circular frequency,
<br />
> s - ground conductivity.
<br />
> Xc = 1/(w*C) - antenna reactance,
<br />
> C - antenna capasitance.
<br />
> 
<br />
> For 136 kHz and s=1 mSm/m a is about 0.01
<br />
> 
<br />
> 
<br />
> The formula is very aproximative but yelds reasonable value of R.
<br />
> 
<br />
> Now I work on more advanced formula wich should be more accurate.
<br />
> 
<br />
> Any coments please!
<br />
> 
<br />
> 73 de RA9MB/Alex
<br />
> http://www.qsl.net/ra9mb
<br />
> 
<br />
> 
<br />
> 
<br />
> <p><hr><b>Join Excite! - <a href="http://www.excite.com" target=_top>http://www.excite.com</a></b><br>The most personalized portal on the Web!