[TowerTalk] Ring Rotors

[Richard Thorne]

Another commercial option:

http://www.idctechnology.net/sw/sw.html

Rich - N5ZC

On 1/30/2023 5:08 PM, Grant Saviers wrote:
> Might be better as a new topic "swing arm mounts"
> 
> Some expert advice I got was to use crossed A36 angle steel (2x2x1/4 or 
> 1.5x1.5x3/16) U-bolted to all three legs and mount the rotator close to 
> the tower on a 3/16 plate bolted in the V in the outside gap.
> 
> Repeat for the top bearing, xx feet above the rotator.  Could use a 
> stock "thrust" bearing or a simple UHMW block with all the load on the 
> rotator.
> 
> The swing arms were about 33" long mounted the the mast, which was going 
> to be 1-7/8" x 0.188" 1026 DOM.  The mast was to be 13ft between mounts 
> so able to mount 2 yagis.  A triangular brace mast to arm and a stub 
> mast welded on the arm to mount the antenna with a stock mast-boom 
> clamp.  Of course YMMV.
> 
> It's important to have all three legs capture the loading.
> 
> Ideally get it all hot dip galvanized or do a good pant job.
> 
> And find a PE to recommend a design for the planned yagis.
> 
> Grant KZ1W
> 
> On 1/30/2023 11:32, Steve Maki wrote:
>> 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
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