In a message dated 97-06-17 17:24:57 EDT, you write:
> >> Guyed Rohn 45, 70', 70MPH is only rated for 17.5 sq.ft.
> >
> > Actually, if you add in the 8.0 sq.ft. that Rohn has deducted for a
> >commercial antenna mount, you get 23.5 sq.ft. Just FYI.
>
>
> No, 17.5 is including the 8.0 side mount. Rohn specifies 9.5 sq.ft. in
> the catalog.
>
My mistake - I didn't look it up. For your example above (70' @ 70
MPH), the Rohn spec shows 15.9 sq.ft. Adding the 8.0 sq.ft. already netted
out gives you a total capacity of 23.9 sq.ft.
The 9.5 sq.ft. figure you cite is in the rectangular box meaning that
it is the figure for "flat member" antennas. You should more properly use the
other figure, the one that is in the rounded box; this is the one for "round
membered" antennas. Amateur yagis are round membered antennas.
The only truly flat antenna that I've ever seen is a flat piece of
material that is used as a microwave path reflector (it functions like a
mirror and you can change the path with it). Every other antenna has been
round membered (FM broadcast, cellular, microwave, paging, amateur, etc). My
suggestion is to use the round member figure unless you feel for whatever
reason that it isn't valid.
73, Steve K7LXC
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