According to DB maximum exposed area for DB-420 is 3.33 square feet (3.09
flat plate equivalent)
http://www.decibelproducts.com/ds_pdf/db420_pg262-263.pdf 2nd page
Quoting from a 1990 Rohn catalog on 25G: 170 ft tower rated at Rnd member
antennas 8.1 square feet.
Flat member antenna 4.8 square feet
These numbers are with a 5/8" diameter line on each leg of the tower.
I will have only a 1 5/8" (or maybe 1 1/4) line on one leg and the DB-420 at
the peak. If required I could side mount the DB-420 but I really don't
won't to.
I understand that this is outside of the "envelope"
Thanks
R
----- Original Message -----
From: <K7LXC@aol.com>
To: <srefurd@earthlink.net>; <TowerTalk@contesting.com>
Sent: Thursday, June 26, 2003 3:50 PM
Subject: Re: [TowerTalk] Rohn 25
> In a message dated 6/25/03 9:32:34 PM Pacific Daylight Time,
> srefurd@earthlink.net writes:
>
> > I have been given 170 feet of Rohn 25G in excellent shape. I live in
> > Jackson County. FL. Wind zone is 95 MPH
> > Honest opinions on setting up tower?
>
> You didn't mention what your proposed windload would be.
> >
> > I understand that the 25G is only rated at 90 MPH in any configuration
over
> > 100 feet. BUT it is rated at 90 MPH at 190 feet. Will the 20 foot
> > reduction give me enough of a safety factor?
>
> You might want to have a PE or engineering-type run some calcs on your
> proposed installation. You still need the windload info.
>
> > As much as I have read about
> > Rohn's conservative nature is this excessively risky?
> >
> Might be - it depends. Tower capacity is a direct function of leg
> strength; 25G legs aren't real substantial so they have their limits, as
do all
> towers.
>
> The towers are designed to TIA-222 specs so ALL towers are
conservative.
> In all cases the LXC Prime Directive should be observed: "DO what the
> manufacturer says." Failure to comply is at your peril.
>
> Cheers,
> Steve K7LXC
> TOWER TECH -
> Professional tower services for commercial and amateur
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
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