On Wed,1/25/2017 7:23 PM, john@kk9a.com wrote:
This is a half sloper so the tower is a radiator.
Not necessarily -- it depends on how it is being fed. I have two wires
sloping off my 120 ft tower. They are insulated from the tower and fed
from the bottom against four radials elevated about 20 ft. I feed one or
the other, but not both. The tower, with a 3-el SteppIR and long 2M yagi
is long enough to act as a reflector, yielding about 6 dB of F/B.
Because the tower is part of the antenna, I have 8 quarter wave
on-ground radials on it.
This is, of course, not the only way to feed wires sloping off of a
tower, and some nice looking arrays are in the ARRL Handbook and/or
Antenna Book.
73, Jim K9YC
Whether it works well or
not depends on the tower and other mounted antennas. I imagine that this is
addressed in the Antenna Handbook. You would likely have better results
shunt feeding the tower or using a wire vertical.
John KK9A
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 160m Slopers
From: jimlux <jimlux@earthlink.net>
Date: Wed, 25 Jan 2017 17:41:36 -0800
On 1/25/17 4:42 PM, Chuck Dietz W5PR wrote:
I have a 140' tower with several beams on it and I want to get back on
160m. I want to put up a 1/4 WL sloper, but my experience has been that it
will only barely cover 1/2 the band. I have measured out two slopers, one
133' long and the other 127' long. Can I feed both together with the same
feedline? (Adjusting the longer one first.)
Yes, and both might need adjustment.. There's something in the Antenna Book
about this kind of antenna. You also need to space the two wires apart a
bit.
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