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TopBand: Inverted L questions

To: <topband@contesting.com>
Subject: TopBand: Inverted L questions
From: w8ji.tom@MCIONE.com (w8ji.tom)
Date: Wed, 09 Dec 1998 10:09:38 -0500
Hi Tad,

> 1.  As a connection point for the radials, radiator and coax cable, is
> there any advantage in using a 1:1 current balun, or should I just use a
> dipole center insulator?  

If you have a good radial system, with no voltage difference between the
common point and earth, there is no need for a choke balun. 

Impedance matching is another issue.

If you use a sparse radial system, elevated or otherwise, a choke (current
balun) is a good idea. It will prevent common mode currents on the
feedline. These common mode currents are a source of many problems,
including loss of efficiency on elevated systems (I measured about 1 dB
addition loss when I grounded the common point of a four wire elevated
system, and more even additional loss with a two wire and a truncated
elevated system).

> 2.  I plan on starting with about 12 ground radials.  Is there an easy
> way to get them to stay where I want them on the ground - like plastic
> staples?

You can staple them. I used to lift a chunk of sod with a narrow spade
flipping it over with roots still attached on one end, push the wire across
the hole, and replace the clod of sod. I could pin down the wire without
even bending over.

73 Tom

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