Subject: [TowerTalk] Half sloper recommedations needed
From: rlvz@aol.com
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).
Dick- K9OM
Edgewater, Florida
Since you already have a 90' tower with tribander on top, why fool around with
a compromise antenna like
an inverted-L or half sloper? Just shunt-feed the tower itself and use it as a
top-loaded vertical. You
will need some radials, and if it is a guyed tower, install some strain
insulators on the guys. But that
would seem to me to be less trouble than what you are proposing to do.
You didn't say why you have to pull up the radials each spring, but I assume it
would be to allow for
the field to be cultivated over the summer for farm crops. Otherwise, lay the
radials on the ground and
they will bury themselves in the sod in a year or two. I once had a ground
system over a cultivated field
and had to roll some of them up every spring. I put a fence post for each
radial at the edge of the field
and affixed the rolled up wire over the summer. Rolling in or deploying the
radials took only a couple of
hours each time. At the time, I had about 30 quarter-wave radials and had to
pull in about half of them to
approximately 50 ft.
A greater problem with the top loaded vertical or inverted L may be in
receiving. The vertical may pick
up too much local electrical noise to be useful for weak signal reception. A
separate beverage, loop or
something like a flag or pennant may be more satisfactory for reception.
73,
Don, k4kyv
_________________________________________________________________
Your E-mail and More On-the-Go. Get Windows Live Hotmail Free.
http://clk.atdmt.com/GBL/go/171222985/direct/01/
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|