[TowerTalk] The K0FF 5/8 40M antenna with picture links

[n4kg@juno.com]

On Thu, 7 Sep 2000  "K0FF" <K0FF@ARRL.NET> writes:
> 
> Recent computer analysis points out that the radiation angle 
> can be  severely affected by an inadequate groundplane, 
> and in reality it's no better  than a 1/4 wave.
	
	Not surprising. (N4KG)

> Nonetheless, I've always romantically thought of the 5/8 as 
> the ideal, mostly because in the AM broadcasting industry
> it is considered so  (and so did John D. - in his 1st book).
> 

The AM Broadcasters are interested in _ groundwave _ 
along the horizon.

Amateurs are more concerned with _skywave_ from 5 to 30
degrees on 40M.

A simple 1/4 Wave Vertical with LOTS of radials (>30) will provide 
more useful radiation for skywave propagation with less complexity 
or effort than a 5/8 WL vertical.

Also note that tall tapered verticals distort the current distribution
from the 'ideal' represented by a constant diameter over the full
height of the antenna.  Skinny top sections carry much less 
current than would be carried by a continuous section equal
in diameter to the lower portion of the antenna, effectively 
making the antenna look shorter.

So much for romance.  Sorry.  :-(

Adding switchable matching networks for 80 (and 160)
would be useful.  :-)

No need to "resonate" radials laying on the ground.
Extend them to 1/4 WL on the lowest frequency in use.

de  Tom  N4KG

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