Doesn't this drawing for R45 also ASSUME an 8 sq ft side mount
(for dish antennas)? IF that is the case, and you do NOT install
the dish mount, you can add ~8 sq ft to the rated load for R45.
And YES, placing the guys at the TOP is a stronger configuration.
Unfortunately for us, the ROHN Catalog drawings are NOT
drawn for optimum AMATEUR applications :-(
Tom N4KG
On Mon, 30 Sep 2002 Chuck Counselman <ccc@space.mit.edu> writes:
> 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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