I needed a piece of steel mast. I am using a Hazer and need about 2 feet
out of the Hazer to clear the top of the tower and about 3 more feet to get
the KT-34A a respectable height above the tower. A few more feet above the
beam could hold a 2 meter antenna or something light. I'm not going to try
to stack very much on the Hazer. I thought surely I could find an
acceptable piece of steel tubing locally.
The first thing I did was go back through Towertalk archives. I found that
"Schedule 40, etc" did not seem to be acceptable, and was sometimes
referred to as "water pipe". I saw messages about the MARC program and
realized that I should have ordered it a long time ago. I decided that for
my application, chrome-moly was not necessary if I could find a good grade
of structural tubing. This led to some surprising conversations.
First, I went to a local steel distributor. I had never been there, and
was surprised to find a large firm that appeared to employ almost 100
people. The sales rep. told me that they mainly fabricate things, and
they do business all over the U.S. He would be glad to sell me a piece of
tubing (pipe) though. I showed him an ad from Texas Towers (2", high
carbon steel, 79,000 psi yield) and told him that was what I wanted. "Oh,
what you need is Schedule 40", he said. I asked him if they didn't have
anything better, and he assured me that Schedule 40 and Schedule 80 were
all they used, and their structures carried extremely heavy loads, as well
as human beings. I asked about the psi yield rating, and he waffled a
little. "We are only concerned about downward pressure, dead weight
capacity. We don't really have a spec for the wind loading stuff you are
talking about".
Anyway, I was surprised to hear that Schedule 40 was considered by some to
be structural material, even if the specs I wanted were not available.
He gave me the exact dimensions for the Schedule 40 and 80 pipe, and I
left. I looked in the Glen Martin (Hazer) catalog, and saw they had mast
tubing at a very attractive price. I also noticed that the dimensions
looked strangely familiar. I called them and, yes, it was Schedule 40!
They said I could probably get it locally and save the shipping charges.
They also told me that UPS could ship up to 9 feet lengths. I thought the
limit was 7 feet. If Texas Towers has a 9 foot mast, maybe I'll just order
one. Or maybe the truck freight charges on a 10 footer won't be more than
I am willing to pay. (Or - TT is only a 6 hr drive - and I could also visit
some computer stores!) Maybe K5RC has some input for me, also.
I don't think I am presenting any new information here, or really asking
any questions, but it was an interesting afternoon.
73,
Dennis, W5RZ
Russellville, Arkansas
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