Re: [TowerTalk] Fwd: Mast/tower design close in guyed by shrouds and spreaders?

[Patrick Greenlee <patrick_g@windstream.net>]

I got a bargain tower that is a current project for refurb and 
reinstall. It started life as a 100 ft tall tower with a wind generator 
on top.  Gyroscopic forces generated by wind shifts without the wind 
slowing before changing directions resulted in the top 60 ft and the 
generator falling to the ground in a twisted mess.  I bought the bottom 
40 ft for about $200.  I have tilted it over to the ground and will soon 
dismantle it for transport to my location. The legs are made of 6 each 
20 ft lengths of 4 inch ID 1/4 inch thick steel tube with welded on 
flanges for bolts. Hopefully I will have better luck with the tower than 
the original owner.  I do not anticipate massive gyroscopic forces in 
the service for which lit will be used.
73

Patrick NJ5G


On 5/19/2014 9:56 PM, Hans Hammarquist via TowerTalk wrote:
> I think you can find what you are looking for if you check out design of towers 
> for wind generators. They are usually a cone shaped structure. A other approach 
> is how towers for high voltage (and i mean really high voltage) power lines are 
> designed.
>
>
> The power line towers appears much more like "standard" ham radio towers (My 
> opinion.)
>
>
>
> I would not try to design something from scratch.
>
>
> Hans - N2JFS
>
>
>
> -----Original Message-----
> From: Ray, W4BYG <w4byg@att.net>
> To: towertalk <towertalk@contesting.com>
> Sent: Mon, May 19, 2014 3:19 pm
> Subject: [TowerTalk] Mast/tower design close in guyed by shrouds and spreaders?
>
>
> Is there any readily available design/build information for designing a
> modest height (35 to 46 feet) ham tower or mast, that would be close guyed
> using spreaders?  This would allow guying with close in dimensions, probably
> anchored about the same distance from the base as the spreaders are long.
>   
> It would be something like what is done with spreaders and shrouds on
> sailboats.  I have studied the subject relating to sailboats but the related
> sail mast bending forces seem to complicate the subject.
>   
> Close in guying is practical and possible with proper design.  I am aware of
> an original 1000' TV tower in Jacksonville, FL (ch 4) that the guys (no
> spreaders just straight guys) went out somehting less than 200'.  Ch 17's
> original 1000' tower (in downtown Atlanta) was self supporting and as I
> recall only had a base of about 50 maybe 75'.  So wide 2/3h and 3/4h guying
> is not always necessary.  With good information, close in guying schemes
> should be in some circumstances, possible and practical.
>   
> Anyone have any insight on the subject?
> Ray, W4BYG
>
> "The Republic (America), can survive a fool like Barack Obama, who is after
> all, merely a fool.   It is less likely to survive a multitude of fools,
> such as those who made him their president." Vaclav Klaus, Former Premier
> Czech Republic
>
>   
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