[TowerTalk] Opposing boom to mast plates?

[Steve Maki]

That's what I used to think, but when shown how the vectors all cancel 
out when the elements AND boom are mounted at their exact centers, I 
became convinced otherwise. Of course boom to mast clamps are often not 
at the boom center, so that throws things off a bit.

-Steve K8LX

On 09/18/23 1:28 PM, Gene Smar via TowerTalk wrote:
> The balancing to which I referred (and which I should have defined) is wind coming onto the Yagis broadside to the radiating elements, not broadside to the boom.
> 73 de Gene Smar AD3F
>
> Sent from my Radio Shack TRS-80 model 100 laptop
>   
>    On Mon, Sep 18, 2023 at 1:21 PM, Chuck Dietz<w5prchuck at gmail.com>  wrote:   I don’t understand the physics of how that works. If I imagine that I am
> looking straight down from over the mast and I have a Yagi that has more
> wind area in the front than the back, then it will exert a twisting force
> on the mast trying to turn the mast to the left no matter which side of the
> mast it is clamped to.
>
> Chuck W5PR
>
> On Mon, Sep 18, 2023 at 12:14 PM Gene Smar<ersmar at verizon.net>  wrote:
>
>> I believe the problem that's looking for a solution here is balancing the
>> twisting torque imparted on the rotator, not bending moment exerted on the
>> mast. Mounting hf Yagis on opposite or alternating sides of the mast will
>> reduce the twisting torque versus having them on the same side.
>>
>> 73 de
>> Gene Smar AD3F
>>
>>
>> Sent from my Radio Shack TRS-80 model 100 laptop
>>
>> On Sun, Sep 17, 2023 at 8:33 PM, Stan Stockton
>> <wa5rtg at gmail.com>  wrote:
>> Seems to me if you really believe mounting antennas on opposite sides of
>> the mast is going to make a difference in whether the mast bends you
>> already have a problem regardless of how you mount the antennas. I would
>> think mounting the top antenna just a few inches lower would make more
>> difference.
>>
>> 73…Stan, K5GO
>>
>>> On Sep 17, 2023, at 7:22 PM, Chuck Dietz<w5prchuck at gmail.com>  wrote:
>>>
>>> Well my masts are very heavy. Weight of the antennas is not a real
>> factor.
>>> And saying someone is not an engineer doesn’t help either.
>>> I believe It is a fact that the wind forces on Yagi antennas pointing in
>>> the same direction are transmitted to the mast in the exact same manner
>>> regardless of which side of the mast they are clamped to. It is a fallacy
>>> to think that they would exert force in the opposite directions and
>> cancel.
>>> Chuck W5PR
>>>
>>> On Sun, Sep 17, 2023 at 4:03 PM<k7lxc at aol.com>  wrote:
>>>
>>>>> They were minimizing eccentric loads off the vertical centerline by
>>>> putting one on either side. It won't do anything for reducing turning
>>>> torque or wind loading, of course.
>>>>
>>>>      Looks like you're not a Professional Engineer.
>>>>
>>>> Cheers,
>>>> Steve      K7LXC
>>>> TOWER TECH
>>>>
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