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Date: Wed, 19 Apr 2006 16:04:31 -0400
From: Dexter McIntyre <dmcintyre@att.net>
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Subject: Re: LF: Top load coil at ground level?
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Peter Martinez wrote:
> Effectively what Dick is suggesting is having the coil physically at the 
> bottom where it can be housed and adjusted, but electrically at the top. 
> This is done by extending two wires down the antenna such that the 
> currents in these two wires are equal and opposite and they therefore 
> make no contribution (or degradation) of the antenna performance.  If 
> the antenna is electrically short anyway, it doesn't help to say this is 
> a stub with a specific electrical length, it's just a coil connected 
> into it's place with a pair of wires.
> 
> If the antenna was hollow, or like a lattice tower, the wire from the 
> top hat could come down to the bottom inside the structure, so long as 
> it didn't arc across!


This type of antenna is what I used for WD2XKO during most of the past 
winter.  It seems to work well.  A US patent was issued which covers 
this design.  A link to the patent is on the WD2XKO web page at:

http://www.w4dex.com/wd2xko.htm

Dex,
W4DEX / WD2XKO