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Re: [rsgb_lf_group] Re: LF: Effective antenna height?

To: [email protected], [email protected]
Subject: Re: [rsgb_lf_group] Re: LF: Effective antenna height?
From: "Mike Dennison" <[email protected]>
Date: Sat, 23 Sep 2017 15:32:01 +0100
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References: <[email protected]>, <[email protected]om>
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Thanks to Andy (your pages included the important reference to Watts' 
VLF Radio Engineering) and to Dave for the pages from Watts. I now 
see how useful it was for Peter Dodd to digest the original data into 
simple figures for a typical amateur station. I will add this 
reference to the next edition of LF Today (if I am asked to do one!) 
and to the LF chapter of the Radio Communication Handbook.

Mike, G3XDV
==========

> I have the very book in front of me.  The LF Source Book
> 
> There is a littel bit of justification for those values, but not much.
> They seem to be experimental Photo of the two pages covering LF
> Verticals can be found here
> 
> http://www.g4jnt.com/DropF/lfsourcebookpg210.jpg
> 
> http://www.g4jnt.com/DropF/lfsourcebookpg211.jpg
> 
> Andy  G4JNT
> 
> 
> 
> On 23 September 2017 at 11:18, Mike Dennison
> <[email protected]> wrote:
> 
> > Knowing the effective height of a Marconi antenna is essential in
> > the calculation of radiated power /antenna efficiency at LF/MF. The
> > formula for this includes figures for the capacitance to ground of
> > the vertical and horizontal wires. The result being somewhere
> > between 50% and 100% of the actual height.
> >
> > As long as I have been interested in LF - over 20 years - I have
> > seen (and used) a figure of 5pF/m for the capacitance of the
> > horizontal wire and 6pF/m for the vertical wire. However, I have
> > recently been asked how this figure originated, and must admit that
> > I don't remember. Was it amateur experimentation, or a professional
> > source such as the Admiralty Handbook? The very first amateur UK LF
> > book, a slim spiral bound volume by Peter Dodd, may have the answer
> > but I don't have a copy. Peter's bigger follow-up book, The Low
> > Frequency Experiemnter's Handbook, published in 2000, already takes
> > these figures as understood.
> >
> > Can anyone help, please?
> >
> > Mike, G3XDV
> > ==========
> >
> >
> 
> 
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