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Re: Topband: Covered /bare antennn wire

To: Tom W8JI <w8ji@w8ji.com>, John Langdon <jlangdon@outer.net>, Bruce <k1fz@myfairpoint.net>, topband@contesting.com
Subject: Re: Topband: Covered /bare antennn wire
From: HAROLD SMITH JR <w0rihps@sbcglobal.net>
Date: Fri, 16 Nov 2012 13:42:28 -0800 (PST)
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Very true Tom,

I am using on 20 meters a Telrex 20M546. The Telrex uses a T network. The T 
bars 
are very close to the driven element and longer than normal. They use no series 
capacitors. 

Or should I say condensers as they were called when Mike Arcelino designed the 
Telrexs.

73 Price W0RI



The only noise caused by an element charging is a "pop" or arc as the element 
moves closer to air potential, until the voltage is high enough to break down 
some insulation path to earth. This is a huge problem with T network antenna 
tuners that feed big antennas without a ground leak path. The antenna trickle 
charges the output capacitor (with microamperes of current) until the cap 
flashes over. This sudden rings the tank with high voltage, and that blows the 
diodes in the directional coupler detector.

We certainly do not want things to charge to the point something flashes over 
and is damaged, but a ground leak does not reduce p-static (corona) noise. A 
ground leak does not reduce the chance of a lightning strike, either. Neither 
do 
those tower whiskers (NASA has extensively tested that).

73 Tom


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