Dear Fred and others,
First I want to thank all those responding. Someday I hope to be able to
discuss aspects of installation. I have been at this since end of '95...
I see the error of my ways :-D Yes, crank-up towers are great for certain
applications, and to bad mouth them would be incorrect.
I would like to *change* my horror story question to one regarding use
model. For those of you that own (have owned) crank up towers: (I want to
avoid the debate between crankups and fixed structures. For my situation,
the fixed-guyed structure is superior - see below.)
My new question is:
How often do you RETRACT the crank up, and for what reason(s). (My permit
conditions indicate that they should be cranked down "when not in use". Do
others have this condition?)
In my present application, (aside from already owning tower sections for 27
I would like to be able to:
1. have a tower which will feasibly handle the loading my design calls
2. side mount antennas.
3. not worry about being around to crank down the tower every time it's
4. Not have to fill two 5X5X10 foot holes with cement.
5. Not have to call the crane (sign) company when I move (and flatbed
My numbers look like this for HDX689 vs. Rohn 55:
1/2 the visual cross section of crankup
1.5x the horizontal wind loading (more on vert) capacity of crankup
1/4 the concrete
1/4 the weight
1/10 the cost
no hoist system required (including electrical drops)
no hoist system to fail (as a practicing engineer, less to go wrong is
Fred, while I have not been able to get a straight answer from the city as
they object to fixed structures, my guess is that they feel they mitigate
impacts if I crank them down each morning before I leave for work... There
been other fixed-guyed and crankup-guyed towers permitted in the city, so
precedence. (I know most towertalkers may not be interested in this part of
story, so I'll defer it to the ham law reflector. But I would like to see
to my question about crankup tower use model.)
If you want to see the city code: http://www.bpcnet.com/codes/thoaks.htm
and search for "roof attachments"
Fred Hopengarten wrote:
> Fred Hopengarten K1VR 781/259-0088
> Six Willarch Road
> Lincoln, MA 01773-5105
> permanent e-mail address: email@example.com
> On Tue, 09 Jun 1998 17:34:15 -0700 Mike Meehan <firstname.lastname@example.org>
> >My little town let me submit plans and computations for two guyed rohn
> >towers. On the day of the first administrative hearing, they imposed a
> >condition on my permit where only crank-up towers could be used.
> >So now I am trying to build a stronger case for the use of fixed guyed
> >towers. They do not seem to understand the concept of leverage, so
> >maybe some horror stories could sway them.
> It would be helpful if you could tell us WHY they denied a fixed
> structure. Sometimes these things are the product of confusion. They
> may think that crank-up permits towers to be brought down during the
> daytime. They may not understand that you may wind up with a
> crank-up/tilt-over with the EXACT same physical appearance as a fixed
> tower. Could you try to ask the building inspector some more questions?
> Are they after safety or aesthetics? If it is safety, mere
> catalog pages showing higher windloads at the same height as fixed
> structures should be the convincer. I'd hate to see you produce horror
> Fred K1VR
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