[TowerTalk] Am I asking for trouble? - tower loading

[Jon M. Knodel]

Thank you everyone for the replies.  They have been very insightful.  I was not planning on installing the motor with the tower - just the hand crank winch.  My original idea was to install my 3 element SteppIR along with a 2 element 40m beam below it on a tall mast (15 or 20 feet).  The tower I was thinking about is the UST TX472 which has a wind rating of 10.3 at 70 mph.  These were my thoughts and the reason I raised the question.

I am now thinking, because of everyone's good responses (and I really do appreciate the help), that I should not overload the tower at the 70 mph as I originally planned.  I will probably step up to the stronger (and more expensive) HDX series and keep my antenna load within the 70 mph rating.

But this raises another question.  The city here has adopted a sustained wind speed rating of 90 mph and a gust rating of 105 mph.  I have never seen winds of these speeds and the civil PE that I work with thinks that they are definitely overly conservative.  But we do get some good winds in the winter here, being right on the coast - probably around 70 mph at times.  So my question now is this:  Since US Towers only specs their towers for 70 mph max, is there a way that I can calculate a rating at 90 mph, using the same method that they used for getting the 70 mph rating?  Does anyone know the UBC calculations used to achieve the EIA ratings?  Do you think that US Towers would provide this information if asked for it?

Thanks for all the help.

...Always wanting to learn more about antennas and towers... Jon, N7XW