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Message-ID: <3.0.1.16.20000110114820.2d276e7a@mail.cc.kuleuven.ac.be>
Date: Mon, 10 Jan 2000 11:48:20
To: rsgb_lf_group@blacksheep.org
From: "Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>
Subject: Re: LF: LF antenna
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At 19:37 8/01/00 +0000, G3XDV wrote:
>>A bit desperate I started my final attempt, again inspired by Mike, G3XDV,
>>who reported an improvement of his antenna by adding some inductance at the
>>top of the vertical section of his antenna. 
>>...
>>The next days reports from several stations (G4GVC, G3YXM, DK8KW) showed an
>>increase of 1 S-point.
>
>Very interested in this report from Rik. At the time I announced my
>success, Rik spent some time running through the maths with me to show
>that theoretically there should be no improvement - and I could not
>argue with that. I recall replying that if practice and theory did not
>agree, believe the practice. Recently, Dick, PA0SE, also argued
>mathematically and by modelling that there was no improvement to be had.

I did some additional measurements on the antenna this weekend, I will
compare them with the data I have from the 'old' antenna (without the top
loading coil) and report to the reflector if anything interestng comes up.
So far there are 3 hams reporting a major improvement by adding some
inductance at the top of the vertical :
DF3LP (who has almost 100% of the total loading coil at the top)
G3XDV (don't know the values of the loading coils)
ON7YD (2mH at the base, 1.25mH at the top)
All 3 have 'objects' very close to the antenna (trees and/or buildings).

Would be interesting to know if other tried 'inductive toploading' and what
their results were.

73, Rik  ON7YD