[TowerTalk] Question on R-TA-45 Torque Bracket
steve at nr4m.com
Sun Jun 16 15:45:17 EDT 2019
Another thing that might make your skin 'crawl' is the way Paul's towers
I believe his brother, an ME, designed all of his rotating stuff. At
each guy ring, the contact points with the tower were hard rubber
rollers. They may have been rollers with the bearings pressed into the
center, or they may have been 'extra' rollers, NOT the bearing that
carried the load. I am not sure of the exact setup.
Although they were hard rubber, if he tensioned the guys as they should
have been tensioned, just sitting there, the rollers would compress and
'flat spot'. Then, when attempting to turn the tower, they would slide,
instead of rolling. Because of this, Paul kept his guys very, very
loose. I don't think it would be much of an exaggeration to say that a
200 foot long guy may have had 4 feet of sag, or 'belly'. These were
fiberglass guys, with no real weight, so sag was not due to weight of
the guy itself. Any tighter and the rollers would slide. I've never
seen anything like it, before or since.
But, that said, it did take a hurricane to take the tower down.
73 de Steve, NR4M
On 6/15/2019 9:31 PM, Steve Maki wrote:
> All great points. A tall skinny tower with slip rings, with many large
> antennas, in a high wind area, is a temporary setup IMO.
> -Steve K8LX
> On 06/15/19 20:32 PM, Steve Bookout wrote:
>> Hello all,
>> Couple of comments on K4JA's tower failure.
>> The lower half of the tower was shielded from some of the wind by way
>> of tall trees at the edge of the field, where the woods started. The
>> upper half went way above the trees and took the full force of the wind.
>> Also, his stuff was fully rotating from the base up to the top, with
>> slip rings at the guy points. Because of this, the guys really had
>> nothing to do with limiting the twisting of the tower. It just
>> twisted as it wanted all the way from the ground to the top.
>>> I would not put more on a tower than Rohn's wind load ratings allow
>>> just because a torque guy is used. A 6 way star guy does a great job
>>> of minimizing twisting. There is more leg compression since there
>>> are more guys wires however a Rohn 45 is designed to go 300' high
>>> and the tower in the post is only 110'. I believe that twisting can
>>> cause tower failure, K4JA's tower twisted back and forth in
>>> hurricane winds until it failed. Adding a star guy is probably a
>>> good thing if the antenna has a long boom. I use star guys and a
>>> taper pier pin base on all of my towers.
>>> John KK9A
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