Jimmie D wrote:
"J. Mc Laughlin" wrote in message
.. .
Dear Jimmie (no call sign given):
Even towers as short, and as relatively simple as what you say you are
considering, involve safety of life issues! Very expensive computer
programs exist that will analyze a tower, however no professional trusts
them until comparing what the program exports with what is calculated
using
a hand-calculator and fundamental concepts.
Textbooks on (mechanical) statics and strength-of-materials would be
appropriate places to start. Even a spread sheet can be used to develop
computational tools, though a real HP calculator can be a great aid. A
good
mechanical engineering handbook (Mark's ?) might have the information, but
might be more difficult to read. Schaum's Outline series might be better
than some textbooks. Of course, you may have this sort of background
already.
If you stay below 70 feet and have trees/buildings all around, wind
loading calculations are relatively simple. (The standard (222G) on
calculating serious wind loads cost about $400.)
Give the group more of an idea of the "boundary conditions" for your
proposal. How wonderful to be able to contemplate having time for such a
project in retirement.
Regards, Mac N8TT
--
J. Mc Laughlin; Michigan U.S.A.
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"JIMMIE" wrote in message
oups.com...
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
Antenna will have to be tall enough to clear the current canopy of oaks that
cover the property. Materials I have on had are way more heavy duty than
what you see towers normaly built of. such as several sections of galvanised
sign post The heavy U shaped stuf with the flange, dont know what you call
it but there is probably 300 to 400 ft of this stuff, lots of rebar. I could
easily build something similar to a Rohn tower with this. Also have a MIG
and Stick welder. There is maybe 2000ft of oil well drilling pipe piled up
out there. Wife pretty much mandated that I do something with it or get rid
of it. She has her ticket too so she is sympathetic to the cause. Ther is
also a neighbor who works on heavy equipment and he has a crane. Wonder what
a few steaks and beers will get me. First I would like to get up my VHF/UHF
stuff. Nothing elaborate here just some stacked Yagi on 2M and 432 and a 5
elemnt Yagi for 6M. The is also a lot of tublar steel some about 6 inches in
daimeter. with inch thick walls, I think he was making TVRO mast out of this
stuff at one time. Hopefully once I get the place cleaned up I might start a
second career, there is a big 30 x 60 ft shop on the property that should be
good for something. Oh, yes I do have a 50ft Rohn tower i was thinking about
tempoaraly erecting thi as a scafold to work off of. Just a thought.
With the oil well pipe I was planning on making a base from three pieces of
it the screw on three pieces and weld bracing on as I go up it then add on
three more pieces and keep going up. I figure I should easily build a 65 ft
tower this way, maybe more. There are also some really tall southern long
leaf pines about 30 years old on the prperty that might be good for
something. These are some of the taler trees and I was thinking about
stringinging soem 75/80M dipoles of of these.
If I had some design info I might could start figuring out how to make the
best use of some of this junk and get a head start on the game.
Jimmie
Jimmie;
If you are planning to use any of the materials you list here I wouldn't
want to be in the same county. All of the items you list are of low
tensile strength. The well casing will fold over when you try to crank
it up. I know from actual testing. My ELMER had a hundred feet of 6 inch
pipe. We put his tribander on the top end and hooked a wench to the
bottom. After one hell of a lot of cranking we turned around to see how
much more we had to go to put straight up. The tribander was still on
the ground and the bottom of the tower was vertical. The pipe had folded
at the hinge point.
Rebar is good for concrete and stakes but not much else. Fence posts are
extremely bendable.
For your safety forget about your scrap steel and buy a commercial
manufactured tower.
Dave WD9BDZ