I am about to put up my first "store bought" tower and intend to do it "by the
book" with permit and inspections. I have decided to put up a 72' crank-up
tower. My immediate plans are to mount my Force12 C-3E tribander (5.9 sq. ft
area) and 13 element 2M beam (1.8 sq. ft area). My county of Marin, CA is a
75 mph wind zone.
After talking with a few locals about their installations I had decided on a
US Tower model TX 472 rated at 18 sq. ft max allowable antenna area @ 50mph.
Problem is that this rating drops to 7.3 sq. ft at 70 mph and I calculate
about 5 sq. ft at 75 mph. Upgrading to a TX 572 rated at 30 sq. ft at 50 mph
solves the problem but at twice the expense and seems like overkill for what
seems to be common practice for supporting a small tribander and a few VHF
goodies. Obviously with the approach of a winter storm which roll in here
from the Gulf of Alaska with some forewarning, thoughts would drift towards
cranking down the crank up. Still even if I could get a permit through these
figures are a worry.
Any thoughts from those familiar with this class of antenna system?
Steve AC6DR
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|