I keep seeing references to not being able to install 20 ft mast with a
gin pole.
My question becomes...Why not. With a long enough gin pole and care it
should be easily accomplished.
First, the balance point is 10 feet from the end of the mast. It's not
too difficult to raise the mast from the balance point if two tag lines
are used. I prefer to attach just a foot above.
Second: Where are you mounting the pole?
It's typically on one leg of the tower, or on the face. If it's a clamp
on don't mount it above the last cross brace. That tower leg has very
little strength by itself and can easily be broken off.
So, let's say we have the top of the mount about 8" below the top of the
tower. It does have to clear the flat top plate which most of them do
and I'd add another 4" for the thrust bearing.
Lets say the pole extends 2 feet into the mount. It's 3 feet for some
using a double mount.
that means we have 2 feet + 8" +4"
+10 feet. or a 13' pole to raise a 20' mast at the balance point.
OR 14' for the one requiring 3' into the mount.
To raise a foot above the balance point would make it either 14 or 15 feet.
Measure your mounts for exact distances.
Trying to place the mount higher, or extend the mast higher *MAY* get
you a few more inches, but at the cost of safety.
If you have the mount(s) and the pole is not long enough, purchase a
pole that is. It may be a few bucks, but will save a lot of effort,
grief, and frustration. Of course get a good, strong alloy.
73
Roger (K8RI)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|