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Old October 30th 03, 11:35 PM
Yuri Blanarovich
 
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I could buy that to an extent I guess. But say if you had a top loaded
vertical, with linear current distribution, the current across the
coil should be appx equal no matter where the coil is placed. But if
no top loading, maybe so.. MK


Top loaded vertical does not have LINEAR current distribution, that is another
simplification, fallacy. Current in the radiator has cosine distribution. At
the base, there is not much difference, just like in cosine of the angle
corresponding to the electrical length of radiator at that point.

Again, this subject of current distribution is important in optimizing the
antenna design by fine tuning the position of the loading coil in the antenna,
combination with top loading etc. Morew current flowing in the radiating part
of the antenna - the stronger the field and louder signal.

The "linear" current distribution mentioned in ARRL Compendium and Antenna Book
is the simplification propagated from Belrose's 1955 QST article. It is close,
but not exact and introduces confusion as it is demonstrated by the flat earth
society.

Yuri, K3BU/m
 
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