K6XN k6xn at comcast.net
Sat Mar 25 19:15:00 EST 2006


When using the allowable antenna area charts for Rohn 25G towers, after we
calculate the wind area for the antennas to go on the tower how does one
allow for the additional surface area of the mast section above the Rohn 25G
that the antennas will be mounted on?

If for example the mast section extending above the Rohn 25G tower to be
used is  2 inches in  diameter and 10 feet long what is the value we should
use for calculating the additional wind load "area" due to the 10 foot mast?
Is it simply 2 times 10 times 12 for 240 square inches for 1.6 additional
square feet or ???  Moving forward would the total effective wind load for
the ensemble to be used in checking the Rohn 25G "Allowable Antenna Area"
then be the wind load for the antennas plus the wind load for the mast?

This is probably obvious to everyone but I wanted to double check before I
put it up an additional tower.  :-).

Thanks, Ted, K6XN 

Ps FYI I am putting up an additional Rohn 25G tower to handle a pair of
vertically stacked 5 element long boom M2 horizontally polarized yagis for 6
meters spaced approximately 13 feet apart.

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