[Antennas] Lightning protection and antenna poles, a Quandary
Jim Isbell
[email protected]
Mon, 05 Apr 2004 09:05:50 -0500
I have a 32' telephone pole in the back yard that supports my inverted
"L" antenna (32 feet vertical and 64 feet horizontal) for 40 and 80
meters. I am getting ready to put up a Spider Beam for 20, 15 and 10.
I plan on a 15 foot x 2" pole that will be fastened to the telephone
pole on a hinge at about 22 feet so that as it is swung into a vertical
position 10 feet of the pole will be against the 32 foot telephone pole
and the remaining 5 feet will stick above it giving me an antenna height
of 37 feet for the beam. I will use a boat winch with stainless steel
cable through a pulley through a hole in the pole at about 27' to pull
the 2" pole into vertical position and lock it there. I can lower the
2" pole to horizontal (just above my roof) for maintenance by slacking
the cable on the winch.
BUT.......as I thought about it I realized that a 15' galvanized steel
pole would be only inches away from my 40/80 meter inverted "L".
Sooo.... I thought, why not make it with a fiberglass pole. Then on
reflection I realized that the steel cable would also be just inches
away from the vertical part of the inverted "L". Soooo... I thought why
not use a nylon or other non conducting cable to the winch. At that
point I thought I had it licked....until I thought about lightning
protection and realized that I would have to attach a ground to the
shield of the feed line where it takes a right angle turn to go up the
pole to the beam and then continue the ground down the pole to the
earth. Now I have another conductor paralleling the entire length of
the vertical part of my inverted "L" . Soooo. ...I though , "Just
leave the ground off and depend on a good ground elsewhere away from the
pole...........But then I realized that the co-ax going up the pole
itself was a conductor paralleling the inverted "L".....
Now the question is...."Is there any way out of this quandary other than
taking down the inverted "L"?"
The inverted "L" is the best antenna I have ever used for 40 meters and
I would hate to loose it.
Or, maybe, am I being to anal about it and it wont affect the "L" anyway?