[TowerTalk] Formula?

[Chuck Lewis]

Chris, ZS6EZ asks--
> 
> " I'm looking for the proportionality constant (c) that relates wind
> speed (v) and antenna surface area (A) to the lateral force on the
> antenna (F), i.e. F = cAv.
> Any ideas, please? "
> 

From:  "Match Your Antenna To Your Tower", Roger A, Cox, WB0DGF
(Telex/HyGain), HAM RADIO, June, 1984.....

	F = PA, 
	where F is wind force in pounds, P is the wind pressure in lb./ft^2, 
	and A is the antenna wind area in ft.^2

	P = 0.004 V^2,
	where V is wind velocity in MPH

	Examples:
	At 80 MPH, P = 25.6 lb./sq. ft. 
	At 100 MPH, P = 40 lb./sq. ft.

	for a 10 sq. ft. antenna, F = 256 lb. @ 80 MPH, 
	and 400 lb. @ 100 MPH

	etc.

Note: The equation P = 0.004 V^2 accounts for gusts and turbulence; 
      for steady laminar flow, P = 0.00256 V^2 should be used.

This is a very useful article, and is available as a reprint from our
esteemed list owner, K7LXC, who must have been too embarrassed to
mention it yet one more time! ;^) 

73,
Chuck, N4NM

--
FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm