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[Towertalk] 45G (guyed) vs. SSV (self-supp'g) 70-ft. tower

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Subject: [Towertalk] 45G (guyed) vs. SSV (self-supp'g) 70-ft. tower
From: (Chuck Counselman)
Date: Mon, 30 Sep 2002 18:50:48 -0400
At 1:06 PM -0700 9/30/02, Michael Tope wrote:
>Aren't those Rohn specs for 45G super conservative (8sq ft at 90 
>MPH) because they place the top set of guys so far below the top of 
>the tower?

Indeed, Rohn's documentation for the 45G and 90 mph (Dwg. no. C870478 
R1) shows the upper guys for a 70-ft. tower attached at 61 ft.  The 
antenna area spec's given in this dwg are 9.1 sq.ft. for an 
equivalent flat plate or 15.2 sq.ft. for the projection of 
circular-cylindrical elements.

I am not a mechanical engineer, but it is not clear to me that the 
tower would be better off with its upper guys attached at the top. 
With the guys slightly lower, the horizontal load of the wind on the 
antenna is balanced somewhat by the horizontal load of the wind on 
the tower below the upper guy attachment point.

73 de Chuck, W1HIS

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