Thread: Tower design
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Old March 14th 07, 01:04 PM posted to rec.radio.amateur.antenna
John Ferrell John Ferrell is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 199
Default Tower design

On 11 Mar 2007 07:44:30 -0700, "JIMMIE"
wrote:

I am trying to find information on build your own tower. As retirement
nears I plan on having a lot more time for doing things like this and
will have a few acres I can devote to an antenna farm. I wouldnt mind
learning to design them from scratch but would prefer a computer
program if one is available. I know to some building your own tower
may not seem practical but my wife and I inherited a lot of the basic
materials when her father passed away. I am especialy interested in
building tubular foldover mast 50 to 70 ft tall. It seems like years
ago I came across a magazine article on this that also had associated
design software. Any help would be greatly appreciated.

Jimmie

I have a Wilson crank up mast that I purchased in about 1980. It was
originally a 77 foot tower but a failure early in its life led to
removal of the top section. The failure was due to a torsional load
(48 element collinear on 440mhz) and other antennas. The section that
failed was about 3 inches in diameter. I appears to be pretty much the
same as what US Tower is selling today.

I have performed needed maintenance through the years and even moved
it from Ohio to North Carolina. In Ohio it was installed as a guyed
tower. It is currently installed un guyed with a home brew device that
allows me to lay it over to work on antennas on the ground.

I feel that every aspect of the mechanism is critical. If it was any
heavier the electric boat winch could not handle the extent ion. If I
had much more weight on the top, the lay over wench (and I-Beam) would
be challenged. It is built just loose enough to not hang on retraction
but not rattle excessively in the wind. I don't even want to think
about what would happen if it jammed on retraction!

The galvanizing is worn off the outside but still in good shape on the
inside. I have replaced a couple of the pulleys and one of the cables
along with miscellaneous clips & such.

When you deal with this thing it is better to think in terms of a
sailboat mast rather than a tower. Most loads you apply try to put a
crease in the tubing or load the extent ion cables.

Your suggested project would require more patience that I have. It
only takes a few hours of welding for me to want to do something else!

I would sell the old tubing & buy a new crank up mast.

BTW, I am currently trying to figure out how I can safely plant a 40
foot utility pole that was a gift....

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"