On Sat, 25 Sep 2004 20:57:48 -0400, Tower (K8RI) wrote:
>Any one have experience with "half slopers"? (half of a half wave with
>the tower serving as the other side)
Not with a half sloper, but with some half-wave dipoles sloping off a tower. I
specifically
chose them over the half-sloper because modeling in ON4UN's book predicted a
somewhat lower angle of radiation (my guess is a couple of dB more at low
angles). At
W6BX (see the qrz.com listing), I have two on different sides of the tower, and
plan to
hang more when I have the opportunity. One is a 3-wire cut for 40, 30, and 20;
the other is
a 2-wire that is full-size half wave on 80 and 40 with loading coils for 160.
(The tower is
150', and the ground slopes down a bit). The site is on a mountaintop, and
while I don't
have any data on the soil, I suspect it is pretty low conductivity.
I don't have a LOT of operating hours in yet, but in what little time I have
put in, they work
VERY well. With 100 watts, I consistently get better reports than I give, and
they do seem
to work well for DX. I also observe what my gut tells me is something on the
order of 6-10
dB of front to back (front being in the direction away from the tower). This is
in line with
what John's models predict.
One of the conclusions that I drew from John's work and his thoughtful analysis
is that
getting the current maxima up in the air is a good thing.
Jim Brown K9YC
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|