In a message dated 99-11-22 19:13:55 EST, email@example.com writes:
> I will presently be installing a new tower installitation in Western
> Virginia on a ridge that is approximately 2200 ft in elevation. I will
> have a wind factor of approximately 60 mph tops in this area. The area
> in prone to heavy lighting storms and am considering PolyPaser
> equimpent. What I would like to know if it would be feasable to use a
> tower such as a heavy duty US tower or would it be better using
> something in the line of a Roh 45? The tower will be in the range of 55
> to 72 ft with a 2 element 40 and a force 12 tribander system?
First question - which county will you be building in? You can look up
the windspeed at http://www.championradio.com under Tech Notes. BTW, the
lowest windspeed given is 70 MPH. Virginia has some 75 and 80 MPH counties.
Next, a US Tower crank-up is rated at 60 MPH (it says 50 in their
literature last updated in 1986) so you've got some juggling to do to get it
rated for your conditions. Since you're on a ridge, I'd probably add 10 or 15
MPH or more to your build specification since you'll be exposed to big gusts
and venturi winds coming up underneath the antennas.
Are you going to get a permit?
The freight alone on your US Tower will probably pay for half of a 45G
tower. The added mechanical complexity of a crank-up degrades reliability and
requires more maintenance than a guyed 45G does. You have to get a backhoe or
other piece of equipment in to unload the crank-up when it arrives on the
truck. You can unload 45G by yourself. You need a backhoe or crane to get it
from where the truck delivered it to the tower base. You can move 45G by
yourself. 45G is rated up to 110 MPH; a crank-up isn't. I could go on.
Cheers, Steve K7LXC
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