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@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@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@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@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@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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