Dick,
I have successfully used full size half slopers on 160m for years. On
my 110 ft tower the half slopers are anchored at the 100 ft level and
they come off the tower at about a 45 degree angle and they droop.
Above the tower top are stacked forty and ten meter beams. I also have
a few full size radials lying on the ground and tied to the grounded
tower base at ground level. IMO you can model this all you want but you
won't really know how well or poorly it works until you install and test
it. Now to do some bragging at my northerly mid west location (some
call it a black hole) here in Saskatchewan. I have just gone over the
200 country/entity level which I believe is the first for any Canadian
station west of VE3. Of course a good receiving setup is a big help
also. You can also check the cluster for the many EU spots for VA5DX
this past outstanding year.
Doug
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of rlvz@aol.com
Sent: December 31, 2009 3:28 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Half sloper recommendations needed
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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