[TowerTalk] Rotator Choice for Larger Yagi

[StellarCAT]

I believe it was called K factor.... the turning radius X the weight of the antenna... if more than one antenna add these individual values... it is indeed more a rating of the effect of the force and momentum on the gearing. The K factor is also an important consideration for towers and has its own page on the Heights Tower Systems site... Texas Towers lists (some) K factors of rotors – there was a site at one point listing a good share of rotors but I can’t seem to find it again. 

Gary 
K9RX


Is there a better way to determine if a rotator can handle an antenna basedon its size rather than just its wind area? Lots of people here haverecommended the M2 Orion 2800, which on paper is rated for 35 sqft, butwhen I asked the tower installer who will be putting the antenna up whetherhe thought the Orion could handle the OB17-4, he said that antenna willtear an Orion up and strip the gears on the output shaft in short order.The OB17-4 has a 39' boom, 17 elements, of which the longest is 48', andweighs 220 pounds. I've noticed that some rotators don't list a sqft ratingat all, but give turning and braking torque in Nm. Is there a way tocalculate how many Nm would be required to rotate an antenna and keep it inplace? I do have an RT-21 controller, which has slow ramp-up/ramp-down toease the load on the rotator by starting and stopping it slowly.The various vendors aren't much help with this as they all say their rotators will handle the load, while at the same time saying theircompetitor's product won't.73, Jerry