[TowerTalk] Ring Rotors

[Lux, Jim]

On 1/30/23 11:10 AM, Steve Maki wrote:
> On 1/30/2023 1:48 PM, Lux, Jim wrote:
>
>> On 1/30/23 9:46 AM, Grant Saviers wrote:
>>> I agree side mount + swing arm is a good option.
>>>
>>> Although my 7 K0XG R65 rings have worked great minus one motor 
>>> failure, I would do side mounts for future (unlikely) towers.
>>>
>>> The advantages of side mounts are lower cost & weight, using 
>>> standard rotators, and if desired with multiple beams on a long mast 
>>> between rotator and top support.
>>>
>>> The side mount disadvantages are less rotation (but still can get 
>>> ~250*), some offset load on the tower (use 6 guys or star brackets), 
>>> and easily fabricated or purchased unique parts, although you/PE 
>>> need a design.
>>>
>>> I think the updated Orion 2800 is a better choice than the Yaesu for 
>>> very big beams. 
>
>> I've been thinking about this, and I wonder if there were some "not 
>> too complex" scheme with an extra hinge point on the arm that would 
>> get you 360 degrees.  Not that I would build such a thing (would that 
>> I had room for it) - but I was thinking if you had an arm that is the 
>> length of a "face" of the tower, and some sort of offset crank 
>> linkage, you could get 360 of rotation from 240 degrees (or less) of 
>> movement from the primary arm.   My mind's eye has this as like a 
>> "wrist" that reaches around the tower. Yeah, you'd have the mass of 
>> the antenna as a cantilever load, which would put a bending moment on 
>> the tower.
>
> A swing arm where the rotor is mounted straight off a tower leg is 
> good for 300° easy. That's plenty as long as you have another antenna 
> to cover the dead zone. 


Oh yeah, I figured that.. I was just contemplating "clever mechanical 
solutions" - The swing arm is actually a nice solution in general - 
simple, uses off the shelf stuff, can be added after the tower is up, etc.


It's like the hinge plates for mounting an antenna on a tower/mast that 
pivots from horizontal to vertical - a simple clever solution.


Of course, the other solution is to mount two (or three) Yagis and a 
combining network to phase them (or just switch). <grin>