[TowerTalk] Ring Rotors

[Steve Maki]

On 1/30/2023 2:23 PM, Lux, Jim wrote:

> 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>

Yep, I was trying to picture your idea. Back when linear actuators were 
cheap (used in the satellite dish industry) I put some time into 
thinking about a way to use one or two to turn a large yagi on a swing 
gate. It never got past day dreaming and a little pencil scratching.

-Steve K8LX