Aha! That's the tower I was thinking of.
Thanks for the post.
73, Dick WC1M
> -----Original Message-----
> From: WA3GIN [mailto:wa3gin@comcast.net]
> Sent: Thursday, May 08, 2008 8:00 AM
> To: Its from Onion; towertalk@contesting.com
> Subject: Re: [TowerTalk] guying a crank-up
>
> Interesting thread.
>
> The Triex CT-100 is a 100ft crank-up tower. It is a guyed tower (at
> three
> locations). The tower sections are lifted by a single cable. Each
> section
> raises the next section by use of a pair of cables that run from the
> bottom
> of the preceeding section over a pulley at the top of that section and
> down
> to the bottom of the next section. When the tower is fully extended
> there is
> a locking pin (fashioned from a 2" x 2" x 1/4" piece of angle that is
> used
> as a pin under a welded piece of 2" x 1/4" bar that is welded on "one"
> tub
> of the second section from the bottom section. So, the entire weight
> and
> stress of the 80ft of tower (rated at 40sq ft and 600lbs of dead
> antenna
> weight) is supported by the welded 2" x1/4" x 1/2" latch.
>
> There are two amazing things about steel. Check out the ratings of
> 1/4"
> steel rope and 3/8" or 1/2" bolts. It takes a lot of force (several
> thousands of lbs) to bring a fault. These towers we use for our
> antennas
> are pretty amazing!
>
> Have Fun,
> dave
> wa3gin
> ----- Original Message -----
> From: "Its from Onion" <aredandgold@msn.com>
> To: <towertalk@contesting.com>
> Sent: Thursday, May 08, 2008 2:59 AM
> Subject: [TowerTalk] guying a crank-up
>
>
> > Not to start a big discussion, but as long as you 'ONLY' guy the
> bottom
> > section of the tower It can be guyed.
> > That is to say, not guy any of the 'cranked up' sections.
> >
> > Pinning the movable sections, like an extension ladder steps will
> only
> > transfer the stress to the rung, cross member, ect
> > that is rests on. Something that is surly NOT designed for that
> stress.
> >
> > Ya must remember its like building hot rod cars when we were kids:
> big
> > motor, runs fast. but who thinks about upgrading the brakes
> > untill its time to stop? In other words, the tower companies spend
> a lot
> > of mony engineering the tower.
> >
> > UNLESS, you also do the same; what makes your design safe, better,
> > strong???
> >
> > Just food for thought... Have you ever SEEN a tower come down?
> they
> > twist into the ground.
> >
> >
> > Lee
> > KE4VYN
> >
> >
> > Message: 1
> > Date: Wed, 07 May 2008 22:02:20 -0400
> > From: jim Jarvis
> > <jimjarvis@optonline.net<mailto:jimjarvis@optonline.net>>
> > Subject: Re: [TowerTalk] ma550 guying
> > To: towertalk@contesting.com<mailto:towertalk@contesting.com>
> > Message-ID:
> > <A8B77C17-F42C-4359-8934-C6F487BA0E15@optonline.net<mailto:A8B77C17-
> F42C-4359-8934-C6F487BA0E15@optonline.net>>
> > Content-Type: text/plain; charset=US-ASCII; delsp=yes;
> format=flowed
> >
> >
> > Ignoring, for the moment, the prime directive, let's look at what
> > you're doing if you
> > guy a crankup tower.
> >
> > The lateral forces on the tower, which cause it to flex and shed
> > load, are transferred to
> > the guys, and to the vertical structure itself. With a crankup,
> > that means to the hoist cable!
> > The cable is not specified for anything more than lifting the
> weight
> > of the tube, with some
> > safety margin.
> >
> > Thus, adding guys to the ma550, or any similar light duty tower,
> will
> > NOT increase its load
> > capacity, or its safety, but will reduce it.
> >
> > Now, if you upgraded the winch cable, carefully calculating the
> > downforce resulting from the
> > increased load area you plan, and the increased wind zone withstand
> > which the zoning requires,
> > you COULD add capacity to the structure. But in that case, be
> > prepared to present an engineering
> > wet seal to your zoning people to justify the structural decisions.
> >
> > It's a whole lot easier and cheaper to follow the prime directive,
> > don't you think?
> >
> > N2EA
> >
> > Jim Jarvis, MBA
> > President-Executive Coach
> > The Morse Group, LLC
> > 732 548 5573 office
> > 908 410 9130 cell
> >
> > People-Process-Strategy
> > Achieving Results in a Changing World
> > www.themorsegroup.biz<http://www.themorsegroup.biz/>
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|