[TowerTalk] Slopers, half slopers, (using the tower)

[Jim Brown]

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