Jim Brown wrote:
>
>>It would be interesting to see a printout of all the diameters,
>>lengths wall thicknesses and any other relevant info for each of
>>the aluminum tubing pieces that comprise one of these 66' vertical
>>antennas.
>
> Yes, it certainly would. But DXEngineering PAID an engineer to
> design that antenna, and they deserve to sell that product to
> recover their costs. It's what's called free enterprise.
>
> 73,
>
> Jim Brown K9YC
No. Free enterprise means that you are free to copy their design
and publish a printout of it, since it isn't patentable and you
didn't sign a non-disclosure agreement. The manufacturer can
recover his costs by volume purchasing of the aluminum at lower
prices than the homebrewer can get it for at retail. It's like
lumber yards that give away plans if you buy the lumber from them.
A long time ago I bought a few lengths of every size of tubing
from Texas towers and built one of these things, before anyone
was selling them. It was very wobbly and hard to erect and likely would
fail sooner or later from fatigue. Because stiffness varies as the cube
of the diameter, 3 inch irrigation tubing is MUCH stiffer than one of
these things and makes a better and cheaper vertical, if you have access
to the tubing, which I realize not everyone does.
Rick N6RK
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