[TowerTalk] PRO CRANKUPS
nollamidzich
nollamidzich@email.msn.com
Sun, 16 Apr 2000 10:21:10 -0500
. Here is my personal
> experience: I have had as many as 4 towers up at one time and for
decades.
> These are all guyed, fixed towers. So far, my total "tower years" is 120
with
> NO failures.
My "total tower years" (NO FAILURES) with Tri-Ex LM-354 towers is
currently 53. One has been up since 1968, the other since 1979.
For those that read my previous posts about 4 months ago, please forgive the
redundancy, but crankup towers, for ME, have been a pretty good choice.
Nothing could be any more dangerous for ME, than to try to climb a tower.
I bought a ranch instead of a colonial home because of my acrophobia. Being
able to crank down and tilt the tower over my roof allows ME a reasonably
safe way to work on the antennas.
There are other alternative antenna support structure options, and the pros
and cons of each have been discussed, but once again for ME, the crankup
option has served it's purpose rather well.
Noll W9RN
----- Original Message -----
From: Stan or Patricia Griffiths <w7ni@teleport.com>
To: Chris Pedder <g3vbl@netcomuk.co.uk>; <towertalk@contesting.com>
Sent: Saturday, April 15, 2000 1:23 PM
Subject: Re: [TowerTalk] Have you had a crank-up come down?
>
>
>
> Chris Pedder wrote:
>
> > I am aware from postings on this reflector that there are considerable
> > differences of perception concerning crankup towers on the two sides of
the
> > Atlantic. I would guess that the majority of amateurs, who have towers,
> > here in the United Kingdom have crankups.
> >
>
> There are lots of people over here who are pro-crankup as well. I,
personally,
> am probably the most outspoken anti-crankup person I know.
>
> >
> > There is a number of reasons for this, not least of which is the
difficulty
> > in obtaining planning permission (building permit) for any sort of
tower.
> > In most areas the ability to retract the tower 'when not in use' is a
> > considerable plus with the planning authorities.
> >
>
> Boy, we have the same sort of problems getting permission to put up towers
and,
> especially in California, it seems, crankups are very popular and for the
very
> same "planning authorities" reasons.
>
> >From the practical viewpoint, how many crankups are ACTUALLY retracted
when not
> in use? I rarely see a retracted crankup. The idea looks good on paper
to
> planning authorities but is rarely put into practice once the tower is
> installed.
>
> >
> > First of all some crankup towers are designed to be guyed. I should say,
> > however, that the tensions used are probably rather less than those used
on
> > a fixed tower. I do not happen to guy my crankup even though it carries
a
> > substantial headload. The usual failure mode, in extreme weather
> > conditions, is bending of the middle section followed by collapse of the
> > entire system. This can be prevented by suitably placed, lightly
tensioned,
> > guys. (As the wind increases the common 'gravity' system used here will
not
> > bring the tower down due to binding/locking of the sections. A positive
> > pull-down would solve this but is seldom used in U.K. and people do not
> > learn to get them down early enough or to guy them loosely.)
>
> One of my points, exactly. People are quite well aware of what they
SHOULD do
> regarding crankup towers, but very often simply DON'T do it . . .
>
> >
> > Before anyone tells me that any guying system increases the tension in
the
> > lifting cables I should point out three things:
> >
> > 1. We use a lock system which takes the tension off the cables.
> > 2. I did say that tensions are lower than on fixed towers
> > 3. The cables will take it anyway.
> >
> > There is, on this reflector, a very evident 'anti' sentiment with regard
to
> > crankup towers and this is a pity.
>
> I can identify with this statement since I am the outspoken "anti" person
and
> the only real "pity" is because of all the tragic accidents that occur
because
> of crankups.
>
> > Each type, fixed or crankup has its uses
> > and each is capable of being used safely over a long period of time.
> >
>
> Here, I beg to differ. If you could obtain statistics, you would probably
find
> that failures and injuries occur MUCH more often on crankups than on fixed
> guyed towers. Of course we can't obtain those statistics since most
people
> are embarassed to discuss their tower failures since most of them are
related
> to their own personal errors or stupidity.
>
> >
> > I will admit that I had a tower 'come down' on me but that was due to
> > criminal neglect on my part, having had a new set of lifting ropes in
the
> > garage for eight years and failing to fit them!
> >
>
> Well, you are one who is not too embarassed to admit it. Thanks for that.
An
> interesting possible way to evaluate "safe use over a long period" would
be to
> calculate the number of "tower-years" a person has had experience with and
> compare that with the number of failures or injuries. Here is my personal
> experience: I have had as many as 4 towers up at one time and for
decades.
> These are all guyed, fixed towers. So far, my total "tower years" is 120
with
> NO failures.
>
> I wonder how that compares with others . . . If you have had one crankup
for
> 20 years and it failed just once, I would regard that as a dismal record .
. .
>
> Personally, I think "planning authorities" are often among the most
> ill-informed and dim people I have ever met. They should be putting
personal
> safety way ahead of aesthetics and crankups should be outlawed entirely as
a
> dangerous hazard. I think the statistics we can't get would show this
very
> clearly . . .
>
> Stan w7ni@teleport.com
>
> >
> > Enjoy,
> >
> > Chris G3VBL
>
>
>
>
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