[TowerTalk] Swing Gate Mounts

Tue Jan 31 10:06:28 EST 2023

I'm with Steve.  I got a neighbor to build me one (he was a talented 
fabricator) after making sure that my second C-3E had enough 
inter-element clearance to swing fully.  Put pieces of radiator hose on 
the legs to serve as stops.  300 degrees it was, almost to a degree.

73, Pete N4ZR

On 1/30/2023 11:06 PM, Steve Maki wrote:
> I was only talking about the gate itself. Of course the wider the 
> tower face, the longer the gate needs to be. And the more thought one 
> needs to put into the element spacing and boom-to-mast clamp location 
> on the boom, especially for 10M yagis. But it's a very good solution 
> for many scenarios.
>
> -73, Steve K8LX
>
> On 1/30/2023 8:03 PM, Grant Saviers wrote:
>> I'm not sure about the swing.  Best to draw it out on the exact tower 
>> dimensions.  Also how the elements clear.
>>
>> Grant KZ1W
>>
>> On 1/30/2023 15:23, Steve Maki wrote:
>>> Yes - the X configured bracing, which gets all three legs involved, 
>>> is how we made all our swing gate mounts and collars in the late 
>>> 90's. That puts the rotor straight off the leg, which automatically 
>>> gets you 300° rotation, right?
>>>
>>> -Steve K8LX
>>>
>>>
>>> On 1/30/2023 6:08 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
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> TowerTalk mailing list
>>>>> TowerTalk at contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk