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
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