In a message dated 7/25/01 1:33:02 PM Pacific Daylight Time, w3svj@juno.com
writes:
> How risky is it to hoist 60 feet of 25G from somewhere above the C of G?
> The club (Steel City ARC, W3KWH) is trying to get the ATV repeater
> receive antenna a bit higher above the tree line. The antenna represents
> about 1.5 sq ft of windload.
>
> The plan is to assemble it all on the ground and secure the top guys as
> well as tie down the hardline. Of course the earth end of the guys would
> secured and the tower plumbed when it is upright.
>
> The concern is, will the tower buckle under its own weight before it can
> be swung to the vertical?
Why couldn't you do it in two lifts? You're going to have two sets of
guys anyway.
The problem with lifting it just above the CG is that the tower will not
be hanging vertically so that it will easily slide onto the base section.
You'd have to pick it from directly above so that it would hang vertically in
order to get the crane lift to work.
As for bending by picking it up more or less in the middle, I don't have
any direct experience with it but it'd *probably* be okay. Try it and let us
know what happens. (Just kidding. The advice is worth what you're paying for
it - hi.)
Cheers, Steve K7LXC
Tower Tech
List Sponsor: Are you thinking about installing a tower this summer? Call us
for information on our fabulous Trylon Titan self-supporting towers - up to
96-feet for less than $2000! at 888-833-3104 <A
HREF="http://www.ChampionRadio.com";>
www.ChampionRadio.com</A>
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
|