Michael,
Not sure if this is what you want. It is what Yaesu recommends when sizing
there rotors for an application.
http://www.texastowers.com/kfactor.htm

Copied from WEB site.

What the heck is "K-factor"?

In addition to windload and torque ratings, Yaesu also offers a
specification called "K-factor," which is derived by multiplying the turning
radius of the antenna (in feet) by the weight of the antenna (in pounds).
Add the K-factor of each antenna on the mast together for your total system
K-factor. The resulting number (in foot-pounds) must be less than the
K-factor rating for the rotator.

I hope this is what you are looking for.

73   Bill   WA4OYH



-----Original Message-----
From: Blind-Hams For blind ham radio operators
[mailto:[log in to unmask]]On Behalf Of Michael Ryan
Sent: Saturday, September 06, 2003 12:33 PM
To: [log in to unmask]
Subject: Antenna K Coeffiicient


Hi all:

Is there a formula to calculate antenna K coefficient?

Thanks to all & 73:
Michael VO1RYN