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Re: [TowerTalk] phasing verticals

To: jim Jarvis <jimjarvis@optonline.net>
Subject: Re: [TowerTalk] phasing verticals
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Tue, 10 Mar 2009 08:50:06 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
There is no need for "storing the phasing lines".  You can
place the phasing network midway between the antennas and
run coax cables of equal length just long enough to reach
the phasing box.  Once there, everything can be done with
lumped elements.  Lumped element solutions have greater
bandwidth than distributed solutions.  You need an adjustable
L and C for getting phasing and amplitude correct, then another
adjustable LC for matching to 50 ohms.  After determining the
component values experimentally, you can replace the L's and
C's with fixed values.  Very simple.  I have actually done this
with a 2 element 160 meter array.

Rick N6RK

jim Jarvis wrote:
> If there's a reason for phasing at the antenna, it's that storing the  
> phasing lines
> inside the shack can impact available space.   But it's a much better  
> solution than
> switching at the antenna, for reasons of phase stability, weathering,  
> and simplicity
> of switching.
> 
> As you know, MF broadcast arrays routinely do their phasing inside  
> the tx shack,
> using a lumped-constant phasing and power splitting network.
> 
> No reason hams couldn't do something similar, and just coil up the  
> phasing lines
> in a box.   Switching could then be done with simple manual coax  
> switches.
> 
> n2ea
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