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Re: Topband: VF - It is what it is

To: "Charles Bibb" <zedkay@bellsouth.net>, <topband@contesting.com>
Subject: Re: Topband: VF - It is what it is
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
Date: Thu, 29 Mar 2007 13:28:53 -0800
List-post: <mailto:topband@contesting.com>
> 
> My solution to the changes-VF-over-time problem in a crossfire phased 
> system is:  To first use equal lengths of it from each Beverage to 
> reach a common point ahead of the un-un. (Change of VF in these 
> sections will not matter, since both pieces are the same length of 
> the same cable, cut from the same spool.  Both pieces will remain the 
> same electrical length as their VF changes identically.)  Then, to 
> add the phasing line to the line from the rear staggered Beverage as 
> a separate piece of cable.  This way the section of line being used 
> to achieve the proper phasing angle of the two antennas can be 
> disconnected periodically, it's VF checked, and be replaced if need 
> be. This would also allow the null to be easily moved for any other 
> Charles - K5ZK

Or you could use a pi network as a lumped delay in place of the separate
piece of cable.  Then you don't have to worry about cable aging at
all.

Rick N6RK

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