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
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