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## [TowerTalk] Rotator and Antenna Standards

 To: [TowerTalk] Rotator and Antenna Standards Chanel1096@aol.com (Chanel1096@aol.com) Mon, 1 Mar 1999 15:18:49 EST
 ```>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 King -- 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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