In a message dated 11/4/2008 1:08:00 P.M. Pacific Standard Time,
towertalk-request@contesting.com writes:
> 10 Feet - 55 Sq Feet
> 20 Feet - 25 Sq Feet
> 30 Feet - 9 Sq Feet
> 35 Feet - 4.7 sq Feet
>
> This is based on the 70 MPH Winds.
>
> To find this chart, go to
> http://www.radiancorp.com/ROHNNET/rohnnet2004/html2004/index.html
> Click on On Line Catalog (Bottom Left of the Menu Bar)
> GT Series (Top Right)
> 25 G (Again, Top Right)
> Then Allowable Antenna Areas
I followed the above instructions and couldn't find the Allowable
Antenna Areas anywhere. :-(
OTOH I do have a Rohn brochure entitled "Manufacturer's Technical
Information for Bracketed or Self Supporting Towers". I don't know the date of
it so I don't know what rev of the TIA-222 it's based on. This is what it
says for 70 MPH:
10 feet - 42.5 sq.ft.
20 feet - 22.0 sq.ft.
30 feet - 12.0 sq.ft.
35 feet - 8.7 sq.ft.
40 feet - 5.1 sq.ft.
45 feet - 2.3 sq.ft.
I'm not sure how to reconcile the different specs but if you're
going to err, err on the side of being conservative engineering-wise.
For the record there is another base spec for a self-supporter that
is kind of hard to find too.
For the guy who wanted to go 45 or so feet above a housebracket with
45G @ 70 MPH, the same pamphlet says
14 feet above the housebracket is 31.0 sq.ft.
24 feet above the housebracket is 13.8 sq.ft.
34 feet above the housebracket is 5.5 sq.ft.
Cheers,
Steve K7LXC
TOWER TECH
**************AOL Search: Your one stop for directions, recipes and all other
Holiday needs. Search Now.
(http://pr.atwola.com/promoclk/100000075x1212792382x1200798498/aol?redir=http://searchblog.aol.com/2008/11/04/happy-holidays-from
-aol-search/?ncid=emlcntussear00000001)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|