[TowerTalk] Rohn RSL tower - slightly off topic
ki7m at comcast.net
Fri Jun 7 21:32:09 EDT 2019
Just seems to me your heading for your beam would have to be so accurate into or away from the wind that it would take a 'perfect world' scenario to have this happen. And doesn't the wind shift around putting different pressure to one side or the other of the antenna? I don't think the exercise is worth whatever gain you might get if there is any.
> On June 7, 2019 at 4:45 PM Steve Maki <lists at oakcom.org> wrote:
> On 06/06/19 19:18 PM, john at kk9a.com wrote:
> > I missed the torque part however I wish someone could explain this in simple terms.
> I'll give it a try.
> Stick a tennis ball on top of a mast. It creates no rotational torque in
> the wind.
> Stick the tennis ball on the side of the mast, it creates torque in the
> wind, like a wind vane.
> Picture a balanced boom (balanced for wind...and weight if you like, but
> I don't believe the weight is important for this).
> Picture the boom going right thru the mast (ala Telrex elements that
> went thru the boom).
> A hypothetical symmetrical wind comes along. The boom does not rotate
> because everything is balanced.
> Now move the boom to one side of the mast. The wind will now attempt to
> move the boom *downwind*, IOW, perpendicular to the wind on the downwind
> side of the mast, because of the lever arm created by the distance
> between the mast center and the boom center. Kinda like a weather vane.
> Now add a second identical boom to the other side of the mast. Voila,
> things are balanced again for wind force vectors.
> I have to say though that it would seem that because of the small lever
> arms involved, this concern is not worth putting much effort into. The
> effect can easily be dwarfed by antennas that are not wind balanced.
> -Steve K8LX
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