Ron,
My suggestion would be to use the standard 4-square array layout and add a
center element. The center element would be the driven element and the 4
parasitic elements would be directors/reflectors/no effect. I suspect that
the two side elements would be non-contributors, leaving the "rear" element
as a reflector and the "forward" element as a director. Two ways to tune the
parasitic elements come to mind:
1. Bring coax back to a center switch box. I think the best idea
would be that all coax length be cut equal to provide the correct reactance
to be either a reflector or director. Additional reactance would then have
to be added to either the front or rear elements (via the coax) to get the
desired effect. Modeling would dictate what to do with the side elements.
2. The other possibility is to have tunable/switchable reactance at
the base of each parasitic array and change the reactance to change
direction.
I don't maintain that this solution is either easier to implement or offers
better performance then a standard 4 square array.
Another idea in regards to a parasitic array is the Spitfire array invented
by Fred Hopengarten (K1VR) and John Kaufman (W1FV). You can read about it
at this link: http://www.yccc.org/Articles/Spitfire/spitfire.htm
73
Chris, n4vi
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Ron Feutz
Sent: Sunday, February 20, 2005 9:29 PM
To: towertalk@contesting.com
Subject: [TowerTalk] parasitic 4-square for 40 meters
>
>TT'ers
>
>I have everything I need for a parasitic 40 meter 4-square but can't find
>design info.
>
>I want to try this antenna as my marginal cost will be zero. I have 4 33'
>verticals, an Ameritron RSC 8-V switch and plenty of radial wire and coax
>on hand.
>
>Any info on design and tuning will be appreciated. I believe the design
>has 3 "reflectors" that use the inductive reactance of the open feedline to
>make them "reflectors," right. How long should the feedlines be? I can
>tune with the MFJ 259B.
>
>Any models out there to tell me what to expect?
>
>Archive and google search turned up nothing.
>
>73,
>
>Ron KK9K
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
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