mast

[John Brosnahan]

At 08:02 AM 10/20/96 -0700, you wrote:
>Howdy all,
>
>     I wonder what people use for mast that sticks up about 10 or so
>feet above the tower and holds more than one multiband antenna? 
>     I put up 1 1/2" galvanized steel pipe and it failed......bent right 
>over. Wow! 



Jeff,N3MLV,

Prime example of why not to use water pipe -- it isn't rated
for structural use!


>     If I use 1 1/2" galvanized steel again,only this time schedule 80,
>which is 1/4" wall thickness,is that sufficient? And if that is
>sufficient, what would be the difference between steel or aluminum pipe
>if they both are the same thickness?I don't have time for this "chrome
>molley" or whatever it is as this must be changed immedietly, no time to 
>wait for freight! One last question, I also suppose I could use 2" 
>instead of 1 1/2", but adding all this more weight,is it really going
>to add all that more strength? Helping answers appreciated!!! 

Strength goes up much faster for an increase in diameter compared
to the increase in wall thickness--better to use 2" thinner wall 
than 1.5 inch thicker wall.

Just how many times can you afford to do it before you do it right?
Guess the panic has to do with the upcoming contest but since
I don't know where you live I can't help you find a local supplier of
real steel tubing, not pipe.  You don't necessarily need a special
chrome moly tubing, just an appropriate grade of steel tubing for the
mast.  But almost any reasonably sized city will have a steel 
supplier that will have some chrome moly in stock--you don't have to
order it from out of state.

Good luck

John  W0UN


((crude program forwarded to Jeff to make the needed calculations))

John Brosnahan  W0UN
24115 WCR 40
La Salle, CO 80645

"Radio Contesting IS a Contact Sport"


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