[TowerTalk] Vertical Antenna Tubing Strength (was: Increasingeffective 4SQR array bandwidth???

[Richard Karlquist]

>I am still trying to make 80 meter verticals that hold up well. I was 
>thinking or irrigation tubing, but it is so soft and thin it scares me. I 
>don't mind guying it, but installing the irrigation tubing seems to be 
>a problem.
>73, Tom W8JI

>Is there software available for calculating stresses, or proven plans 
>that work for an 80-meter vertical that is easy to erect?

It is no problem to walk up 60 feet of 4 inch irrigation
tubing if you have a helper pulling on a rope to 
assist.  Using the falling derrick method, one person can
do it. See:  http://www.karlquist.com/Irrigation/irrigation.html

The stresses when doing this can be figured out easily
with a calculator using a few basic equations.  They
approach 10KSI in the above example.  That is about
all the irrigation tubing can take before it starts
to take a set.  With the falling derrick method, 
you can eliminate most of this stress.

Rick N6RK

richard@karlquist.com
www.karlquist.com 

 


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