Tower Ratings - Stupid Question

Bob Morris K2RK robrk@fyi.net
Thu, 19 Dec 1996 22:09:53 -0800


K7LXC@aol.com wrote:
> 
> In a message dated 96-12-19 18:17:22 EST, you write:
> 
> >I am also trying to study the tower literature for an installation
> >next year.  I have had a comment that at least one manufacturer
> >(is it Tri-ex?) states that their crank-up sections are specially
> >strengthened in the area of the overlap.
> >In this case the tower is weakened if the owner lowers it half-way
> >down, under storm conditions?
> >
>       The forces on a crankup are obviously at their maximum when the tower
> is fully extended.  Having the overlap areas beefed up is a good thing to do
> since most hams load their towers to the max and leave them extended.  When
> the tower is lowered, the overall forces are reduced because there is less
> surface area exposed and there is less moment of force on it.  If you have a
> tower with a  load that exceeds the wind speed rating, you can lower the
> tower an amount (that you have to determine) until you reach a height that is
> safe for that wind load and speed.
> 
> 73,  Steve  K7LXC
> 
>     TOWER TECH -- professional tower supplies and services for amateurs
> 
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I hear people putting guy wires on self-support or crank-ups,
thinking they are improving wind load etc...
Is this not a -bad thing-?

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