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## [TowerTalk] Rotator and Antenna Standards

 To: [TowerTalk] Rotator and Antenna Standards n4zr@contesting.com (Pete Smith) Mon, 01 Mar 1999 22:01:10 -0500
 ```At 03:18 PM 3/1/1999 EST, Chanel1096@aol.com wrote: > >>Question for the MEs out there -- how would you combine wind torque and >>measured inertia/momentum to produce a real number, that could be compared >>with rotating and braking torque specs to determine if a given rotator will >>do the job reliably? > > >> >>73, Pete Smith N4ZR >>n4zr@contesting.com > >In trying to combine wind forces and starting torque needed to overcome >inertia, it would be relatively easy to look at the combination of the two >based on a set wind velocity (speed and direction) however there is the crux >the problem. In looking at a wind speed, we are approximating the wind and >the often quoted 70 mph figure is a fastest mile wind which is currently being >phased out as all new wind data is based on 3-second gusts in which 90 mph is >the new base wind speed. Even your previous 70 mph numbers had to use Gust >Effect factors to obtain wind forces. So our wind forces which get >approximated as static forces are not static but dynamic. In addition wind >can fluctuate greatly over a small area as well, in the national building >codes they have two different wind loads, one for an entire structure and >another for individual components of the structure. All of this really boils >down to the fact that you can add the 'base' wind load torque created and the >required starting torque but I doubt this new number will mean anymore to real >world operation then the current 'K' factor which seems to be causing so many >problems. Bill makes a good point. Virtually any "standard wind environment" is going to be, at best, just an approximation. However, since the current K factor makes no allowance for wind forces at all, I think that any benchmark that includes both wind and inertial components has to be an improvement. 73, Pete N4ZR Loud is good -- 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 ```
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