[NLRS] US tower MA series question

Mon, 11 Aug 2003 18:40:21 -0500

I really like the looks of these, but....

The problem with these is that they are only rated at 50 MPH in the 
extended position. And they don't even talk about ice loads. You may have 
trouble with local building codes. We do down here in Iowa.

Even retracted, there is another problem: The base that holds the tower has 
a very critical weld to the flange that is over-stressed unless it has been 
x-rayed. (and they don't) I solved this for one of our guys by having him 
house bracket the tower to his fireplace chimney chase after doing some 
extensive bracing. He says he can really hear it creaking the whole roof 
structure of his family room when he has it retracted and the wind is 
kicking up.

These MA550 and the old Rohn DBX and HDBX series have given me lots of 
problems and unhappy friends because I can not PE stamp them for use in our 
rather strict building codes down here.

Steve NA0IA
ARRL Volunteer Consulting Engineer.

At 05:04 PM 8/11/2003, [email protected] wrote:
>Just wondering if someone out there has experience with US Tower
>MA-550MDP or similar.  (The tubular tower look is the best choice for
>my sub-division as is the 23 ft lowered feature -). The base looks
>fairly straight forward (1.66 yds of concrete) just wondering about
>opinions of the 4 ft tower top rotor mount and the optional (yet
>expensive) controller.  Also wondering about resources for home-
>brewing a controller around the limit switch kit.  As for antennas
>looks like the biggest up there would be the M2 6MX5.  Would like to
>have 144 and 222 as well (home is good location for AU).  Any
>opinions of the US tower products appreciated.
>  73,
>Matt
>KF0Q
>EN44ea
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