With a half sloper, the tower radiates as well as the wire and the result
may be good or bad depending on the tower configuration. The only way to
know the pattern is the model the system or build it. You could try shunt
feeding your tower or running a wire vertical hung from one of the guy wires
keeping it away from the tower.
John KK9A
To: towertalk@contesting.com
Subject: [TowerTalk] Half sloper recommedations needed
From: rlvz@aol.com
Date: Thu, 31 Dec 2009 16:27:57 EST
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Hi Guys-
I'd appreciate your recommendations on building a Half Sloper for 160-m.
I realize that some folk have had excellent results with Half Slopers and
others have had terrible results with them! That's why I'm asking for
advise on how to construct my Half Sloper!
Question 1: Most antenna articles say when constructing an Inv. Vee is to
keep the minimum angle between wires at 90 degrees or greater. Since Half
Slopers almost never have a 90 degree angle between the sloper wire and the
tower is this one reason why many Half Slopers don't work very well... lots
of signal cancellation?
Question 2: I have a 90' tower with a Tribander on top which makes it very
close to a 1/4 wave for 160-m. I installed an Inverted L on this tower
with 85' vertical and the Inv. L radiating efficiency is very poor due to
heavy coupling between the Inverted L and the tower. (some models say that
alot of RF is shorted right to ground!) Therefore, I am thinking of going
with a Half Sloper connected near the top of the 90' tower with the sloper
wire running NE towards Europe. If I anchor the end of the sloper wire
about
200' from the tower the angle is only going to be about 45 degrees. Do
you think this will work any better towards Europe than my heavily coupled
and inefficient Inv. L? (another weakness with my Inv. L is that I have a
minimal radial system as it must be pulled up each Spring).
Question 3: Rather than build the Half Sloper on the 90' tower would an
Inv. L on my 60' tower with 55' vertical and the rest horizontal running NE
towards Europe likely outperform the Half Sloper at 90' towards Europe...
keeping in mind that this is a temporary antenna so I can only put down a
minimal radial system as the radials need to be removed in Spring.
I realize that I'm likely to get a variety of opinions on this and that is
fine! Please let me know which of the above options you believe is most
likely to provide the best 160-m. signal towards Europe.
Happy New Year!
73,
Dick- K9OM
Edgewater, Florida
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