[TowerTalk] Mast loading calc's

K7LXC@aol.com K7LXC@aol.com
Mon, 2 Nov 1998 10:40:07 EST

In a message dated 98-11-02 09:12:02 EST, n7ex@athenet.net writes:

> I need the formulas for wind loading and  on a mast. And the constants for
>  2" water pipe.

      They are all in W6NL, ex-W6QHS, Dave Leeson's book, "Physical Design of
Yagi Antennas". Buy a copy for your library. 
>  In particualr what is the max wind rating for 2" water pipe 10' high with 5
>  Sq feet of antenna?
>  or said another way
>  How high above the tower can I go with 5 SQ ft of antenna using 2" water
>  pipe for 85 MPH wind survivability?

      According to my MARC Program (Mast, Antenna and Rotator Calculator),
five feet of mast @ 85MPH produces 9506 in-lbs of bending moment and
recommends a 32K psi yield strength mast with 0.120" wall. I think schedule
40/80 is somewhere around 25/30K psi. You could go a couple of feet but that's

     The MARC Program is available from Champion Radio Products for only
$9.95. www.championradio.com or 888-833-3104 for more information.

Cheers,  Steve    K7LXC
Champion Radio Products

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