In a message dated 96-08-14 09:39:19 EDT, you write:
>Now, as I am in the process of PLANNING a 45 g tower I am very interested in
>anything concerning R 45g! Am I right in assuming that the 45g is capable
>of 8 more sq footage of beam ( theoretically ) than is stated in the
>manual? If so, this really helps explain why I've heard so many Hams over
>the years state that Rohn has a "safety margin" built into their specs.
>This is not a safety margin per se, but it does help me in my planning
>tremendously ( assuming I'm right in my assumption!)
Mike --
Yes, the 45G (and 55G) is capable of supporting an ADDITIONAL 8 square
feet at the top of the tower. This was confirmed in a phone call to Rohn
engineering this morning. The figure in the drawing is for antennas ONLY.
Since commercial antennas typically use side arm mounts, Rohn has already
deducted it from the square footage wind load of the tower. For amateur
purposes, we don't use them so you can ADD the 8.0 square feet to the figure
given in the Rohn catalog to arrive at an amateur-type wind load.
Of course there is an additional engineering safety factor built into the
figures already. This engineering safety factor doesn't have anything to do
with the discussion of the additional 8 square feet of wind loading
available.
73, Steve K7LXC
TOWER TECH -- professional tower supplies and services for amateurs
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