I have no problem climbing a couple of feet up a mast on a "real"
tower, but my Glen Martin 17' rooftop tower worries me when I have to
get all the way up. I'm afraid the whole top of the tower is going to
bend catastrophically at or just below the level of the rotor, 3' from
the top.
I really should run numbers to see what kind of bending moment I have
when the antennas subjected to a substantial wind, and I suspect I'll
come up with a number that'll make me less worried.
Given that Glen Martin says 12 square feet of antenna at 87 mph, is
there an easy way to turn that into a measurement of force?
I suspect that they caveat that rating by specifying that the antenna
is right at the top of the tower, so there'd be very little bending
moment from the mast.
Note that Glen Martin has and advertises a "climbing lattice" on one
side, but the documents that come with the tower say to not climb the
tower.
I'm not worried about the mast at all, and I have a "medium duty"
mast. (but then I've climbed a skysail mast to 100 feet up, at sea in
the Southern Ocean).
73, doug
Message: 8
Date: Mon, 23 Jul 2007 03:21:50 -0000
From: "J. Gordon Beattie, Jr., W2TTT" <w2ttt@att.net>
Greg, Carl et al,
I like climbing and am perfectly happy climbing towers, rocks, constructed
walls, etc...I spent most of a beautiful Friday evening and most of an even
more beautiful Saturday this weekend up on my tower and roof doing antenna
and tower work...I am a twice certified Climbing Director by the Boy Scouts
of America...I teach climbing to youngsters and adults...but there are
limits...I don't like climbing things that move...not ice, not really tall
trees and NOT 2 inch masts!
I agree with the sensation of climbing things like a mast...when I need to
stand on top of the tower to tighten bolts on an H-frame to a mast, I GET
THE POINT that this is really NOT GOOD!
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Gregg Seidl
Sent: Monday, July 23, 2007 1:06 AM
To: TowerTalk@contesting.com
Subject: [TowerTalk] Masts with steps
I climbed up my mast about 4 feet to install a large 222Mhz antenna.Boy that
sure does give me the hebeshebes.I tell my brain that this is 2 inch .25
inch wall 1026 pipe and that I could stand up here in a 70 mile breeze and
it won't bend.I go up there and my body is calling my brain a dumb(%!
because it sure FEELS like it going to bend over.I think it is the movement
that scares the crap out of me. Gregg K9KL
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