[TowerTalk] mast, torque balance questions

[ersmar at comcast.net]

Dave:

     1.  Maybe Dillsburg Aeroplane Works near Harrisburg, PA might be a source for aluminum. http://www.dimebank.com/monster/burst/00229.html .

     2.   Torque-balancing is an attempt to distribute the effective area of all the elements, including the boom, on a Yagi antenna system so that net torque on the mast is zero, irrespective of the direction of the wind.  This will have the indirect effect of minimizing the torque required from the rotator to turn the array.

     My Bencher Skyhawk Yagi has a couple of PVC components among the director elements that, supposedly, help to balance or reduce the net torque on the mast by compensating for the necessarily longer reflector elements.  You can see a photo of one of the two <torque compensators> at:  http://www.bencher.com/sky_hawk1.html .  The short (PVC) tube on the left between the 10M and 20M directors compensates for the greater amount of element material on the reflector side of the mast.  Not clearly seen is a vertical flag of PVC plate that mounts above this PVC tube.  That flag compensates for the greater boom length on reflector side of the mast.  Yes, both of these PVC items add a bit to the total wind area of the Skyhawk.

     I'm guessing that having a better-balanced Yagi array permits the rotator to turn it with less effort in a wind than if the Yagi were left uncompensated or unbalanced.  I don't believe that the inertia of the array is affected by such compensation.

73 de
Gene Smar  AD3F

 -------------- Original message ----------------------
From: "David J Windisch" <davidjw at cinci.rr.com>
> Hi, all concerned:
> 
> 1.  Searching for 24' of 2"OD X 0.25" wall X 24' length 7075 T6 alloy 
> aluminum mast has turned up nothing.   Any help on sources out there, pls?
> 
> 2.  Is "torque-balancing" of a boom a balance of sorts between wind effects 
> and inertial start/stop forces on a rotator?
> 
> TIA & 73,
> 
> Dave, N3HE
> 
> 
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk