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[CQ-Contest] 160 Receiving Antenas

To: <cq-contest@contesting.com>
Subject: [CQ-Contest] 160 Receiving Antenas
From: "Hal Kennedy" <halken@comcast.net>
Date: Thu, 30 Aug 2007 11:18:34 -0400
List-post: <mailto:cq-contest@contesting.com>
With the exception of a very small multi-turn loop very high off the
ground, every receive antenna is ground dependent.  Worst of all IMHO is
the EWE, where the earth forms one of the elements - leading to
unpredictable results and no directivity in a desert.  Beverages are
also highly ground characteristic dependent - they don't work over salt
water - but they can work well in a desert setting with radials.  Two on
each end, on the ground, is typically enough - approximately 1/8
wavelength long and perpendicular to the Beverage wire.  Short verticals
require decent grounds.  The phased verticals I've modeled and built all
required radials to work - a minimum of four per vertical is suggested.
Short-vertical systems typically use lots of series R and some series L
to maintain a flat SWR over the frequencies of interest - some of the
series R can be in the ground rather than a resistor.    I am currently
using a K9AY loop here - one ground rod is usually enough to get one
working properly - a few short radials can be helpful if the soil is
really bad.  N5OT has the right idea - phase a pair and you will have a
surprisingly good antenna.  A good K9AY is not as good as a decent
beverage, but they take up nearly no space and can be built for $10 and
put up in an hour.


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