Wind pressure varies as the square of speed. Thus 80 MPH has
64/25 = 2.56 times the force of 50 MPH. The necessary reduction
in antenna area has to be even more than this factor, because
reducing the antenna doesn't reduce the wind load of the tower
itself. We can conclude that the LUSO tower is the kind that
you need to crank down for severe storms.
Rick N6RK
Larry wrote:
> I forget the exact numbers but wind pressure is something like 20 psi at 50
> mph, 30 psi at 86 mph, and 40 psi
> at 100 mph. There are many other factors obviously that will affect the
> load.
>
> 73, Larry W6NWS
> ----- Original Message -----
> From: "Art Trampler" <atrampler@att.net>
> To: <towertalk@contesting.com>
> Sent: Sunday, November 15, 2009 2:56 AM
> Subject: [TowerTalk] Luso Tower/wind load rating
>
>
>> OK, am I missing something here? If I am understanding how Luso states
>> the wind load ratings on its “smaller” towers, they are rated at
>>
>>
>>
>>
>>
>> 53.8 sq.ft. (Maximum wind speed: 25 m/seconds at full extension) 53.8
>> square feet at only 56.25 MPH wind.
>>
>>
>>
>> 25 * 3.3 (approximate feet in a meter) * 3600 / 5280 = 56.25 MPH.
>>
>>
>>
>> So, in rough terms, rating at 80 mph is about 40% greater wind speed, so
>> the rating at 80 mph would be about 20 square feet (.6 * .6 * 53.8)?
>>
>>
>>
>> That seems awfully low…what am I missing?
>>
>>
>>
>> Art Trampler, KØRO
>>
>>
>>
>> _______________________________________________
>>
>>
>>
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>
>
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