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## Re: [TowerTalk] KT34XA Torque Balance

 To: "Red" ,"Tod - Minnesota" ,"TowerTalk" Re: [TowerTalk] KT34XA Torque Balance "Michael Tope" Sat, 8 Jan 2005 00:08:31 -0800
 ```----- Original Message ----- From: "Red" To: "Tod - Minnesota" ; "TowerTalk" Sent: Friday, January 07, 2005 5:32 PM Subject: Re: [TowerTalk] KT34XA Torque Balance > Hi, Tod and TTers; > > Tod presents 'an elegant solution." Furthermore, by optimizing the > length and diameter of the arm versus area of the vane, one can minimize > the wind loading on the tower and mast. > > I recall that this aspect of antenna design and the calculations are > addressed in David Leeson's book, "Physical Design of Yagi Antennas." > I don't believe he includes calculations for any of the KT34 series, as > he does for several popular antennas, but he offers all you need to > calculate the wind induced torque. > > 73 de WOØW > > Tod - Minnesota wrote: One caution, Red - John W0UN sent me an email letting me know that the portion of Leeson's book that describes the need to torque balance elements with dummy elements is incorrect. It seems that Dick Weber K5IU has written on this subject pretty extensively and that all you need to do is to torque balance the boom, which by the way is way out of balance on the KT34XA (the boom wind torque balance point and the center-of-mass balance point are offset by about 20"). If you look at what Weber writes you find out that don't need to worry about the elements because the wind forces on a symmetric element always act in the direction perpendicular to the element (what he describes as the "cross-flow" principle) which means that force on the element gets applied in-line with the boom so there is no net torque from the elements. The elements have to be symmetric of course, but most are, so happily I no longer need to worry about doing wind force calcs on the nightmarishly complex KT34XA elements. All I have to do is something like Tod suggests where I balance the forces acting on the boom. 73 de Mike, W4EF....................... _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread [TowerTalk] KT34XA Torque Balance, Michael Tope RE: [TowerTalk] KT34XA Torque Balance, Tod - Minnesota Re: [TowerTalk] KT34XA Torque Balance, Red Re: [TowerTalk] KT34XA Torque Balance, W0UN -- John Brosnahan Re: [TowerTalk] KT34XA Torque Balance, Michael Tope <=