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Topband: Shuntfeeding

To: <topband@contesting.com>
Subject: Topband: Shuntfeeding
From: k6se@juno.com (k6se@juno.com)
Date: Fri, 12 Oct 2001 10:07:25 -0700
Barrie, W7ALW wrote:

"Also, regarding radials:  I've been told dozens of things about radials
over the years.  I won't quote them all here, but these are a few that
concern me:

The more the better?"
----------
Yes, of course.
==========

"All must 1/4 wavelength long?"
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It depends on the number of radials.  It has been found that as the
spacing between the ends of equally-spaced radials becomes greater than
about one meter, the advantage of making that long decreases rapidly. 
!20 radials, each 125 feet long, would have this spacing.  This means
that if there are only 32 radials, there's not much to be gained if they
are made longer than about 35 feet each.
==========

"Doesn't matter how long they are, some may be very long or very short?"
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See the above.
==========

"To be effective they must be #8 wire or larger?"
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No.  The RF current is divided among the radials, so much smaller size
wire is adequate.
==========

"Each must be terminated with a ground rod?"
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No.  This has been shown to be of no help.
==========

"Each must be as straight as possible?  They don't need to be straight,
they can curve or go around houses, 
 etc?"
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They should be as straight as possible.
==========

"Radials must be evenly distributed around the vertical antenna?"
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Ideally, yes (see the spacing rule of thumb mentioned above).

73, de Earl, K6SE

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