Re: Tower design

Dear Jimmie D.:

You certainly have some useful raw-materials and auxiliary items (crane,
welding equipment). However, safety is of first importance.

Welding of the members so as to preserve strength is not simple. Put
another way, one could put together and erect a structure that can stand on
its own. However, once subjected to wind or other disturbances, it could
fall. You are coy about your location, but if you are in a coastal or
near-costal area, peak wind loads could be very large. Your soil might
require especially crafted foundations.

Other than the references I suggested, I do not know an inexpensive set
of design information. Use Google to see what exists. Whatever you find
needs to be used with caution. Gaining a fundamental understanding from one
or more of the references will put you in shape to know whether what you
find on the Internet is believable. Wind pressure formulas that are found
on the Internet are often wrong - at least until one knows the assumptions
being used. If you need a building permit to erect a tower, you may be
required to have a Professional Engineer certify that the tower conforms to
reasonable standards of workmanship and the requirements of the 222G
standard.

You have the part of the solution that is usually the most expensive.
It is desirable to learn the critical, low cost part that allows you (and
others) to be reasonably safe. Indeed, with the help of a local P.E., you
may be able to clean the property and assist other radio amateurs with
simple towers. Be safe.

73, Mac N8TT
--
J. Mc Laughlin; Michigan U.S.A.
Home: JCM@xxxxxxxxxxxxx
"Jimmie D" <GFENDER@xxxxxxxxxxxxxxx> wrote in message
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"J. Mc Laughlin" <jcm@xxxxxxxxxxxxx> wrote in message
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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.
Home: JCM@xxxxxxxxxxxxx
"JIMMIE" <JIMMIEDEE123@xxxxxxxxx> wrote in message
news:1173624269.884477.154000@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
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




.

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