[TowerTalk] rotor plate bolt hole patterns

[K7LXC@aol.com]

In a message dated 02/14/2000 7:03:48 AM Pacific Standard Time, 
ryansci@InfoAve.Net writes:

> Can anyone tell me if the rotor plate bolt hole pattern for the Yaesu 
>  series of rotors (800-1000 series) is the same as for the HyGain T2X 
>  tailtwister? 

     They are both 4-hole patterns but the Yaesu has a little bigger radius. 
Rohn rotor shelves have slotted bolt holes to accomodate both. Your rotor 
plate may be slotted too. How about asking the manufacturer if it'll fit with 
no modifications?

> Would I have to shim a 1 3/4 inch mast to properly center  it 
>  for a TTwister or Yaesu rotor to smoothly turn a full 360? 

     Depends on whether you will be using a thrust bearing or not. With no 
thrust bearing, you can just let the mast turn eccentrically in the top hole 
if that's your scenario. 

> I am going to use the rotor on a rotor base for a US Tower MA550MDP.

     Is the 1-3/4" the mast drive at the bottom of the tower? If so, you'll 
probably need to shim it if you want to use a Hy-Gain rotator. I have seen 
very few shim schemes that worked; generally they slip. You might want to 
talk to a local machine shop and come up with a reducer scenario that'll work 
better. Or go with a Yaesu rotor since you don't have to shim it. 

Cheers,  Steve   K7LXC
Tower Tech

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