[TowerTalk] Tower "DROP ZONE" or "DROP RADIUS" for Rohn 25G &Trylon Titan?

[K8RI on Tower Talk]

It depends on the area in which you live.
Here it is simply the total height of the structure *excluding* antennas. 
They didn't even count the top mast, although I did for safety.

It may be  the height of the tower plus the distance to the tip of the 
antenna (element) farthest from the mast, or the total height of the tower, 
which ever is greater.

Roger Halstead (K8RI, EN73 & ARRL Life Member)
N833R, World's Oldest Debonair (S# CD-2)
www.rogerhalstead.com


> The Building Inspector is requiring my engineering drawings to specify 
> what he is calling the "drop zone" or "drop radius" of the tower.  He 
> wants to see what is the radius of the circle it will all land inside when 
> it all comes crashing down.  (perish the thought!)
>
> I couldn't find this figure in the Rohn catalog anywhere. The one engineer 
> I talked to didn't seem to know about it either.
>
> In case anybody here knows about these, here are some possibly relevant 
> figures for each tower I need this figure for:
>
> 1) A 98' Rohn 25G, guyed for 90 mph at 95', 63' and 32' at a guy radius of 
> 80', with 33' boom on top antenna.)
>
> 2) A 108' Rohn 25G guyed for 90 mph at 105', 70', 35' at a guy radius of 
> 88', with 24' boom on top antenna.)
>
> In both cases, assume 7 sq. ft. of wind load at top of tower plus 4 sq. 
> ft. of wind load at 2/3 tower height and 4 sq. ft. of wind load at 1/2 
> tower height.
>
> 3) A 96' Trylon Titan freestanding with 4.5 sq. ft. at 97' on a 23' boom, 
> 4.5 sq. ft. at 67', and 4.5 sq. ft. at 37', plus 3.1 sq. ft. at 77' and 
> 3.1 sq. ft. at 47'.
>
> If someone can tell me what the values are for the figures I need, or 
> where I can look to find these figures, or how to calculate them myself, I 
> would be very grateful!
>
> John
> WA2GO
>
>
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