Wow, Bob! With just 175 lbs of wind load you would have exceeded the
Rohn specs for 45G, and thats neglecting the additional wind load on the
side of the tower. This corresponds to 7 sqft of wind load at 80 mph. If you
figure that the tower is worth another 2 sqft/section (this is a guess), then
at 80 MPH, the load margin left over the antennas is only 13 lbs of wind
load or 1/2 sqft.
If you figure that your installation was probably 13 sqft of wind load, then
it was probably seeing overturning forces that were 2.8 times the manufactures
ratings when the winds got up to 80 MPH.
Guess they don't want any lawsuits at Rohn.
73 de Mike, W4EF............
-----Original Message-----
From: N5RP [SMTP:perring@texas.net]
Sent: Sunday, May 02, 1999 1:05 PM
To: notawc@juno.com; towertalk@contesting.com
Subject: [TowerTalk] Rohn 45 Self Supporting Tower
Just for the record, I have had 65' of Rohn 45 with a 6 element tri-bander
and a 2 element Hy-Gain 40 meter Yagi installed in two locations.
The first installation in New Orleans went through 2 hurricanes of rather
significant force, and the same combination later went through another
hurricane in Houston.
No damage occurred in any of these mother nature challenges.
I would estimate winds, in all cases, to have exceeded 80 mph.
A fourth major blow occurred later on, when a tornado came though Houston
and completely demolished my 22' mast which was of less than proper strength.
Wind bursts, in this case,,,, who knows??
This same tornado wind did destroy a 50' windmill tower about 3 miles away
from my house. I presume it took the main funnel as a part of it's demise.
Although I now have the tower properly guyed, the fact of the matter is,
the above installation(s) survived quite well on all occasions.
I hasten to add that I don't recommend this as a proper installation
technique, but it is actual testimony to a tried and true field test of
epic proportions.
In other words, I've run the test, and you can now use this information as
fact when it might come to your wondering about how stout is 60'-65' of
Rohn 45 tower.
N5RP
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