If you really want to "improve" the antenna add a helical hairpin to the
feedpoint.
This will give you a 1.0:1 SWR and probably add 75-100 Khz to the 2:1
SWR plot.
7 turns 3 inches in diameter of #6 wire will do it. Just put it at the
feedpoing in parrallel with the balun system.
I did this to my M2 shorty 40 stack years ago and got a great match and
the whole band back.
If anyone wants one or two M2 shorty 40m antennas give me a call.
Jay, WX0B
alsopb wrote:
>
> Marc,
>
> Just for kicks I ran EZNEC for a full sized 2 element beam (24' boom)
> at 24 and 28 M height.
>
> 24 M SWR =1.306 IMPEDANCE =38 -1.8j
> 28 M SWR =1.519 IMPEDANCE =33 -0.5j
>
> Interesting that the impedance actually decreases rather than
> increasing with height as the dipole impedance plot vs height
> predicts.
>
> I don't have a model for the 402CD. It would be interesting to
> actually run such a model at the two heights.
>
> Of course, these values are at the feedpoint. What the reading would
> be at the shack end of the coax is unknown.
>
> 73 de Brian/K3KO
>
> List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems,
> Trylon Titan towers, coax, hardline and more. Also check out our self
> supporting towers up to 96 feet for under $1500!! http://www.anwireless.com
>
> -----
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> Submissions: towertalk@contesting.com
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> Problems: owner-towertalk@contesting.com
--
Jay Terleski
Array Solutions - RME Filters
Phased Arrays - Horizontal and Vertical
RF Switches, Antennas & Towers
www.arraysolutions.com
List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 96 feet for under $1500!! http://www.anwireless.com
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
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