>I was recently given (yep, free) a mast by one of my customers to use
>with an upgrade of the top antennas on my tower. Can anyone assist me
>in identifying what the mast actually is? Here are the details stamped
>on the side of it:
>AL TCH SMLS 304-L ASME 312 1-1/2 SCH 40 HEAT A5557H
>Mike, WA5JWU in Baton Rouge, LA, WA5JWU@aol.com
Hi Mike,
Let me take a swipe at this one. Here's a case where an unknown mast can
be identified, thanks to the mill markings. What you have is stainless
steel water pipe, size 1-1/2, schedule 40.
1-1/2" Schedule 40 pipe (see my previous post) has the following
dimensions: ID - 1.610", OD - 1.900", wall thickness - .145"
Machinery's handbook lists the nominal yield strength of 304L stainless
steel as 30,000 psi. Using a safety factor of 1.5, that gives you a
strength of 20,000 psi for calculations. This is nowhere near the 87,000
psi strength that Texas Towers is listing for the Rohn masts, for
comparison.
Definitely get the MARC mast strength program from Champion Radio to
determine what this mast will hold with the given properties. Not having
used it myself, I am assuming that you can plug in the size and yield data
of a custom mast (Steve, can you comment on this?). You will also want to
find out if MARC uses a built in safety factor or not to help you decide
whether to give it the full yield strength value or a reduced one.
--...MARK_N1LO...--
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