EMT used as mast...NO!

[Bill Coleman]

>From:        David L. Thompson, thompson@mindspring.com
>
>Please don't!  EMT bends easily and is not suitable for masts.

Not all EMT is that thin. For *SHORT* masts carrying *LIGHT* loads, it is 
perfectly acceptable. The pieces I've seen have walls that are at least 
1/8" thick.

>I have
>several pieces here that
>I carried away from both TV and amateur installations that are bent.    Even
>schedule 40 water pipe (inexpensive at any plumbing or large hardware
>supply) is better for short pieces.  For extensions where multiple antennas
>are stacked you must use reinforced galvanized pipe or heavy wall aluminum.
>Many in Atlanta had good luck with heavy walled aluminum from Tull Metals.
>It comes in 20' lengths but costs over $200.

I used a 10 foot piece of 1 1/2" thick-wall EMT to hold up an A3 for four 
years. Bending it would take a special tool and a LOT of leverage. It is 
heavily galvanized and shows no signs of corrosion even after being 
exposed to the elements. Cost $4 at Home Depot.

$200 to get a 9 foot piece to hold up a R7000 seems like a lot to pay. 
We're not talking about putting up stacks of large beam antennas.

The larger EMT conduit is certainly a better mast material than the 
thin-wall stackable TV antenna masts they sell at places like Home Depot. 
This stuff is make of rolled sheet metal. It rusts in no-time and is 
expensive ($15 for 10 foot piece).

Does anyone have information regarding the load-carrying capability of 
standard EMT conduit?





Bill Coleman, AA4LR           Mail: aa4lr@radio.org
Quote: "Not in a thousand years will man ever fly!"
            -- Wilbur Wright, 1901


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