[TheForge] somewhat off topic: antenna tower

[Blacksmith]

    97 lbs wind load at 100mph means that your 100ft tower would have
to support 97lbs pressure sideways at the top without failure. I don't
know what the weight of your stepped pipe pole would be, but I suspect
erection would be difficult if not near impossible without heavy equipment.
Consider a guyed tower but elevate the guys by using heavy pipe at each
anchor point to get them out of the way of lawn mowers and other
maintenance activities.

Bob Willman
The Eagle's Anvil
Bowling Green, Ohio
WB8NQW

----- Original Message -----
From: <terrylr@blauedonau.com>
To: <theforge@mailman.qth.net>
Sent: Saturday, February 09, 2002 02:32
Subject: [TheForge] somewhat off topic: antenna tower


> hello;
>
> i have searched the amatuer radio pages and have found alot about
> antenna but nearly nothing about building a tower. the little information
> i did find was assuming a large antenna with high wind loading.
>
> basically what i want to do is build a 100 ft tall monopole tower.
> the only antenna on this tower is a 24 db gain parabolic dish microwave
> antenna. the wind loading is slight since it is a wired grid design.
> (
> if you are interested the antenna may be seen at:
> http://www.hyperlinktech.com/web/hg2424g.html
> )
>
> one person suggested i get an aluminum flag pole. hey right they cost
about
> the same as a self supporting tower not including the foundation work.
>
> rohn self-supporting towers cost $10K+. that is way out of my price range.
>
> i thought of using schedule 80 pipe and start out with 8 in pipe.
> use an 8 inch to 6 inch reducer. go with 6 inch for 40 ft and then reduce
> down to 4 inch for 20 ft then end in 2 inch.
>
>          |  |    <---- 20 ft of 2 inch
>          |  |
>          |  |
>          |  |
>         /    \ <---- 4 inch to 2 inch reducer
>         |    |   <---- 20 ft of 4 inch
>         |    |
>         |    |
>         |    |
>        /      \ <---- 6 inch to 4 inch reducer
>        |      |  <---- 20 ft of 6 inch
>        |      |
>        |      |
>        |      |
>       /        \ <---- 8 inch to 6 inch reducer
>       |        | <---- 20 ft of 8 inch
>       |        |
>       |        |
>       |        |
>
> i am unable to find my copy of the machnist handbook to look up the weight
> of each section, so i have no good feel for what it would weigh nor what
kind
> of foundation should it have. it does seem to be over kill for such a
small
> antenna. the only experience i have to go by is when i worked on putting
in
> cellular towers. some of those had 50 ft deep 4 feet diameter concrete
piers.
> with 20 ft long 4 inch bolts embedded in the concrete.
>
> aluminum schedule 80 pipe cost more than steel schedule 80 pipe.
> there are benefits to using aluminum such as weighs less, will not rust.
>
> the reason for building a new tower is the current tower is a rohn 25gt.
> it is next to the house. ( i know bad place to put it. ) at 40 ft it does
not
> need guy wires at 100 ft it need three guy wires per leg. the family has
voiced
> rather loudly that they do not want guy wired. i do not like guy wires
either
> for safety reasons. people get 'clotheslined' by them.
>
> --
> Terry L. Ridder
> Blue Danube Artistic Forge (Blaue Donau Kunstschmiede)
> "We do not bend metal, we sculpt it."
>
> digging deep, i feel my conscience burn
> i need to know who and what i am
> this hunger jolts me from complacency
> rocks me, makes me meet myself
> ----kendall payne---closer to myself---
>
> _______________________________________________
> http://mailman.qth.net/mailman/listinfo/theforge
> theforge mail list group photo site is
> http://www.photoaccess.com
> Login:  blacksmithblacksmith@hotmail.com
> password:  anvil
> ___________
>
>
>