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Re: [TenTec] OT: Antenna Problem

To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Subject: Re: [TenTec] OT: Antenna Problem
From: "Stuart Rohre" <rohre@arlut.utexas.edu>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 18 Jan 2007 18:19:42 -0600
List-post: <mailto:tentec@contesting.com>
IF the feeder end at shack shows 3:1, you could have a loose connection to 
the antenna on only one side, or it could be a balun, or cable choke loose, 
or with water infiltration.

One of the ways to catch a opening up of a feedline, is to put a 100,000 ohm 
resistor across a split feed, if that is what you beam has.  When the beam 
has a good feeder, (both sides connected), you can measure 100,000 ohm 
resistance plus the resistance of the lenght of feedline times two.  If one 
side of the feeder comes loose, you no longer measure 100,000 ohms.  The 
resistor is such a high value, it has no effect on your much lower RF 
impedances at the feedpoint.

Unfortunately, you most likely have an open connection problem, rather than 
a trap problem,since it is on all bands.  Or should I say fortunately, as a 
feedpoint problem is a lot easier to fix than a trap problem when the trap 
is out there on the element.  At least the feedpoint is accessible by 
climbing the tower, if so equipped, and the rotating mast is not too tall.

Stuart
K5KVH 


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