Return to KLUBNL.PL main page

[Top] [All Lists]

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
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=meg.feb2017; t=1506177124; bh=b9OLMbNSpAvPSjzQvTSeCtsBCif22J2IWWzQP9QD6dI=; h=From:To:Date:Subject:Reply-to:In-reply-to:References; b=ld1f3lclxMgkh+xZGPgmdDRijOb1mqYtD3CZ8uG1yP+FB9QnNRj7VHfFdZmDTW1Gv +NGSIeK3lJG74wlNVFSV4uGTek97vUabObEXJgRK7CTrm7QIuQdKYnjhVcITwAyWv1 5Du3NTVzfbZ4A3kZwNzqvPXknEHemcbRNlntQaHVFqwt1jy6uqbJ4EtCROrDLVuMqk yo995xLDxbt0d/mzYIq8Xj5qSMx3L+UQWNEuT8bzR1+iyOossJYcuefLETDLbK8Oaq Wc7iVh71Ags6vLZVzBWKnePA11sdqon76DrYC9PJ7SbDlb/O+y+p9jPoH2qW1BdNAb BNRgtJjfnjv3A==
In-reply-to: <[email protected]om>
References: <[email protected]>, <[email protected]om>
Reply-to: [email protected]
Sender: [email protected]
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
> 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
> > ==========
> >
> >
> ---
> This email has been checked for viruses by AVG.

<Prev in Thread] Current Thread [Next in Thread>