At 10:35 PM 3/15/01 -0000, Barry Kutner wrote:
>Another consideration when using a sidemount with a large
>antenna vs. a TIC ring is the large moment arm create by an offset
>wind load. WIth a TIC ring and Rohn 45, the boom is offset from
>thetower's center by about 10-12 inches. In the case of a side
>mount, it can be several feet. This can create large twisting
>moments around the tower. Perhaps one of our helpful PEs can
>comment further. I'm at the limit of what I remember from my
>25 year old college engineering.
For this reason, I generally park my sidemounted lower antenna on one of
the "stops" (resting against the tower) when the wind comes up, just to
minimize the effective lever arm. In that position, the boom of the
antenna hs
is very close to the Tic Ring situation.
73, Pete N4ZR
Contesting is!
The World Contest Station Database
is waiting for your input at
http://www.qsl.net/n4zr
--
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
|