With a grounded tall tower with uninsulated guy wires perhaps the best
solution would be to install have wave slopers with at least a 45% angle
of declivity and space as far from the guy wires as possible. These
could be either center fed or end fed with a proper matching tuned
circuit. The end closest to the top of the tower should be removed by
about 20 feet to avoid detuning and the grounded tower by itself,
depending on height could be an aperiodic reflector gaining a pattern
bump in the direction of the slope. Having two or more slopers could
even provide some F/B that may be useful. Ground radials are probably
not that much required as with 1/4 wave radiators and the efficiency
should be considered adequate as is.
Herb Schoenbohm, KV4FZ
On 4/24/2014 11:00 AM, Carl wrote:
Ive had inverted V's at 60, 160, and 180' that worked DX that a single
or a pair of full size sloping verticals with elevated radials couldnt
at that particular time.
The high angle often favors sunrise and very deep South into the
Antartic area from here in NH.
For some contests and general domestic QSO's you definitely need all
angles.
On 160 there are no absolutes.
Carl
KM1H
----- Original Message ----- From: "Jim Brown"
<jim@audiosystemsgroup.com>
To: <topband@contesting.com>
Sent: Thursday, April 24, 2014 1:30 AM
Subject: Re: Topband: Suggestions for a tower?
On 4/23/2014 8:51 PM, Ashton Lee wrote:
Also, while you will get some counter argument, setting up an
inverted V off the tower top will work very well too. That may have
a higher angle of radiation but will be very easy to tune to a 50
ohm match.
Yes and no. Although 140 ft may seem high, it's LOW as a fraction of
a wavelength on 160M. :) For several years, I had a 160M dipole at
120 ft. In a LOT of A/B testes, an 86 ft Tee vertical nearly always
beat it.
73, Jim K9YC
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