[TheForge] somewhat off topic: antenna tower

[Shannell]

8" 80 schedule weighs 42 lb/ft steel 14 lb/ft aluminium
6" 80 schedule 28 lb/ft steel 9.8 lb/ft aluminium
4" 80 schedule 14 lb/ft steel 5.1 lb/ft aluminium
2" 80 schedule 5 lb/ft steel 1.7 lb/ft aluminium

Looks like a steel tower would weigh 1780 pounds without taking reducers
into account and an aluminium tower would be about 612lbs.

----- Original Message -----
From: <terrylr@blauedonau.com>
To: <theforge@mailman.qth.net>
Sent: Saturday, February 09, 2002 6:02 PM
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---
>
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