[TowerTalk] wind load

Tom Osborne w7why at verizon.net
Thu Feb 18 19:42:41 PST 2010


Hi Rex et al

Yeah, but for how long?

I've always wondered if that is a sustained 70 mph wind for 5 hours or a 
gust or 2 at that speed.  73
Tom W7WHY




I believe it's saying that at 70MPH, the tower will support 15 sqft of
antenna/mast/whatever is put on it.  Most antennas will specify effective
"wind load" in square feet of "projected area."

      -Rex-

     K1HI
Rex Lint
  Merrimack, NH


I've been looking at various tower specifications, and often see
something like this

Maximum Wind Load
70 MPH 15 sq. ft.

I don't really understand how to interpret this.  I think a wind load
is a (static) force, and therefore should be measured in either
newtons or pounds.  IIUC, it should be proportional to the square of
the wind speed and that the constant of proportionality should itself
be proportional to the cross-sectional area to the wind.  So 15 sq ft
is an area, and 70 MPH is a wind speed, but I'm still missing some
factors in order to calculate a force.

Can anyone shed some light?

73s




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