I have a 105' tower with a cluster of yagi's on top. There are various
fixed-direction yagi's bolted to it, along it's height. There are 17
runs of feedline that come from the tower to the shack. I've always
wanted to install something vertical for 160m use in the quiet winter
months. The 1st and 2nd layer of guy wires are un-insulated from
ground/tower. The top guy wires are broken into full 40m sloping
dipoles and are remotely switched. Due to all of the other rigs
running at the same time and the amount of feedline entering the
shack, I don't think I want to shunt feed the tower for fear of
getting loads of RF in the shack (had a friend who tried this and was
never able to fix the problem with RF in the shack). Here's my
question:

- Can I use insulative side-mount brackets and string a vertical up
the side of the tower, seprated from the tower by a few feet, and get
any kind of decent vertical antenna performance out of this? I was
thinking of maybe 5' off the side of the tower, running a wire up to
105', then shoot the other 30 or so feet of wire off and fold it back
down and outward at 45 degrees or so. Feed it at the bottom, and
install a ground field aound the base of the tower.

I realize there will be some coupling to the tower, but don't have any
way (or know how) to model this. Can anyone help with a model to
determine approximately how much I'll have to compensate wire length
for couplng and top foldback? Have any of you done this before?

Thanks,
ave WB4IUY
www.WB4IUY.net

On Oct 30, 11:50*am, Dave WB4IUY wrote:
I have a 105' tower with a cluster of yagi's on top. There are various
fixed-direction yagi's bolted to it, along it's height. There are 17
runs of feedline that come from the tower to the shack. I've always
wanted to install something vertical for 160m use in the quiet winter
months. The 1st and 2nd layer of guy wires are un-insulated from
ground/tower. The top guy wires are broken into full 40m sloping
dipoles and are remotely switched. Due to all of the other rigs
running at the same time and the amount of feedline entering the
shack, I don't think I want to shunt feed the tower for fear of
getting loads of RF in the shack (had a friend who tried this and was
never able to fix the problem with RF in the shack). Here's my
question:

- Can I use insulative side-mount brackets and string a vertical up
the side of the tower, seprated from the tower by a few feet, and get
any kind of decent vertical antenna performance out of this? I was
thinking of maybe 5' off the side of the tower, running a wire up to
105', then shoot the other 30 or so feet of wire off and fold it back
down and outward at 45 degrees or so. Feed it at the bottom, and
install a ground field aound the base of the tower.

I realize there will be some coupling to the tower, but don't have any
way (or know how) to model this. Can anyone help with a model to
determine approximately how much I'll have to compensate wire length
for couplng and top foldback? Have any of you done this before?

Thanks,
ave WB4IUYwww.WB4IUY.net

a simpler method is to put an insulator at the top of the tower and
run up at an angle so its 20' or so away from the tower at the
ground. the further away from the base of the tower the less coupling
and the more wire there will be going up... and the more art will like
it!

On Oct 30, 6:50*am, Dave WB4IUY wrote:
I realize there will be some coupling to the tower, but don't have any
way (or know how) to model this.

EZNEC will do that. A quick look says that it will work just fine.
There's not much difference in feeding the tower and feeding a wire
parallel to the tower.
--
73, Cecil, w5dxp.com