In a message dated 96-06-19 12:35:44 EDT, you write:
>DO NOT USE ANT TYPE OF WATER PIPE FOR LONG MASTS! Schedule 40 or 80 are
>not designed to handle antennas in strong bending moments caused by wind.
>No matter how big it appears it will bend! I used schedule 80 before I
>knew and it bent in the first major wind and all I had was a 2el Mosley 40
>with a 4el Swan/Hornet Tri-bander 9 feet above.
>I worked as MIS Director at a major Heating/Plumbing supply in the late 70's
>and I got charts on both EMT and water pipe. Both are terrible for any
>antenna application! Lou Tristao sent me a chart on the masts he made
>specifically for stacking yagi's and the only place you should (or could)
>use Schedule 80 is with a beam just above the top of the tower.... as very
>little of the mast is exposed to bending moments.
Dave is correct. Weight does not equal strength. Schedule 80 or water
pipe of any kind is designed to carry liquids and is not rated for strength.
Refer to Stan, W7NI's, article regarding masts that was published in the NCJ
several years ago. If you don't have it, I'll send you a copy.
73, Steve K7LXC
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