[TowerTalk] 43ft Vertical Feeding Question and Balun type,

[donovanf at starpower.net]

Rob,

A 43 foot vertical is 5/8 wavelength on 20 meters.  With appropriate radial and matching systems it can be an excellent antenna on 80 through 20 meters, and a fairly good antenna on 160 and 17 meters.

73
Frank
W3LPL



---- Original message ----
>Date: Thu, 20 Nov 2008 11:49:33 -0600
>From: "Rob Atkinson" <ranchorobbo at gmail.com>  
>Subject: Re: [TowerTalk] 43ft Vertical Feeding Question and Balun type,  
>To: towertalk at contesting.com
>
>I've wondered before what the deal is with 43 foot verticals.   By
>that I mean, it seems suddenly I started seeing 43 feet mentioned all
>over the place for an "all band vertical."  Is 43 feet some magic
>length?  How was this determined and who originated this idea?   I
>figured maybe it was something that had been in the handbooks for
>years and I never knew about it.
>
>Anyway, having a bizarre feedpoint Z isn't necessarily a bad thing by
>itself.  It just means you need a matching network at the feedpoint to
>tune the antenna to 50 ohm unbalanced feed.  What's bad is having a
>vertical so tall in wavelength that you wind up with all or most of
>your RF going off in one or more high angle lobes.  That starts to
>happen when length begins to get beyond around 200 degrees or 5/8
>wave.  There are all these little high angle lobes that gradually
>multiply and get bigger as you go up in frequency.  You have to figure
>out how high you can go in frequency with 43 feet before that happens.
>
>Don't be persuaded by big signal reports on some 100 w. operation with
>no radials.    The right band for the distance with good conditions
>and enough power can do wonders.   20 over S9 with 100 watts when
>everyone else on the band is running 1.5 kw and is less than S9...now
>that's an antenna!
>
>73,
>
>rob / k5uj
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