[TowerTalk] Mast Analysis.

[fev]

 Dave ,if your material is the same in both mast the formula you need is :

{(D*D*D*D)-(d*d*d*d)} / 10*D=WB( Biegewiderstandsmoment)(Bending resitance
moment)

If WB is Biger your mast will be stronger to resist  the force of the wind
over your Antena.

In Your case my calculation are:
For the 2" Mast:   Wb=0.6779 cubic inches.
For the 2,5"mast  WB=0.9225 cubic inches.

So , your best choice is the 2,5"mast with .25" wall instead of the 2" and
.375"wall.

By the way There is a software of Tower Tech call MARC(MASt Antennas and
RotorCalculator) that you can buy in Championradio.com .
If you use Steel the same calculation  is valid to compare sizes of Tubes.
I am using in my instalation a telescopic mast of 4meter 60 mm diameter and
4.5mm wall and inside them 400 mm a another Tube of 4mts long  2
inches(50mm) diameter and wall 7mm.
The total lengh is aprox 7,5mts and over it I will install 2 antensas from
Force 12 .

It was nice to help you, Francisco LU3EEC (Argentina).


--
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com