Re: 33.25ft vertical with KXAT1 - Why did it work?

Posted by Leigh L. Klotz Jr WA5ZNU on Sep 13, 2005; 4:20pm
URL: http://elecraft.85.s1.nabble.com/33-25ft-vertical-with-KXAT1-Why-did-it-work-tp382085p382086.html

Martinm
You can use the ATU menus to find out what value L and C and which
network configuration NT1 or NT2 was in use by the KX1's ATU and you can
see what the L network looks like in each case in the manual.

See http://del.icio.us/tag/EFHWA for more links on end-fed half-wave
antennas, from people who have field experience.

Leigh / WA5ZNU

On Mon, 12 Sep 2005 9:42 pm, Martin Gillen wrote:

> Hi.
>
> I started at 33.25ft vertical but I did leave a pair of 18.5ft
> counterpoise wires running at about 2 feet above the ground connected
> to the ground terminal.
>
> I tuned up and ... 1.2:1 match on 20m!
>
> I then proceeded to work KF6GC with 2W (almost 4000km)
> in the middle of a K Index = 8 solar storm!  So I know
> the antenna worked well.
>
> I modelled it in EZNEC and the impedance at the base
> of that antenna should have been 970 + j 1700 ohms,
> so I am surprised that the KXAT1 was able to match it.
>
> Any comments?  Was it because I left the counterpoises
> connected that it worked so well?  If I remove the
> counterpoises in the NEC model the impedance increases
> and becomes inductive to 1456 - j 1819 ohms.
>
> Comments?
>
> PS.  I am only learning in this stuff so forgive any
> overly simplistic analysis!!
>
> Thanks,
> Martin.
> VA3SIE.
>
>
>
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