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[TowerTalk] QUAD : coax switching and 40m..

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Subject: [TowerTalk] QUAD : coax switching and 40m..
From: dietz@texas.net (C. Logan Dietz)
Date: Tue, 08 Jul 1997 17:35:43 -0500
L. B. Cebik wrote:
> 
> Extensive modeling studies on 5-band 2-element quads shows that the loops
> need to be closed when not in use for minimal interaction.  Opening the
> driven element loops when not in use presents extensive interaction.  As
> well, for a 5-band quad, or even a 3 band or just a 10-20 meter quad,
> separate feeds are needed to prevent serious pattern distortion.  The 1/4
> wl match line (or even just any line) from the driven element loop to the
> remote switch is a good way to effect the closure electrically while
> leaving the loop "physically" open.  

I have juse fed all 3 elements with a common coax on a 4 element
10-15-20 meter quad.  Are you saying this is bad?  I am getting ready to
put it back up.  I use a balun at the feed point.  How will this affect
it?  

Would I be much better to use 3 baluns and a switchbox?  Do I need an
insulated switchbox to let both the shield and center conductor float or
is an aluminum box OK with the center conductor floating?

Does the balun act as a short so that I would be better off with
ferrites over the coax at the feed points?

Chuck, KE5FI

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