> Telrex built antennas before the days of PCs. They did it the old
> fashioned way. They built them to last!
> (snip)
> wa3gin
The old-fashioned way was to use rules of thumb and excessive safety margins
because the mechanics of the material were not sufficiently well understood
to support less rigid designs. It's the same way with buildings - the
modern core-and-curtain skyscraper only became possible because of advances
in the understanding of materials and in improved modelling tools. Before
that, it was essentially brute force pillar-and-beam construction.
Certainly, many of the those older buildings are still with us and will be
around for a long time. Nothing wrong with 'em. However, if you want the
improved efficiency of operation and materials and the advanced designs of
modern buildings, then you will have to use the new techniques.
In the HF antenna world, ask yourself if it would be practical to build,
say, a C31XL using the Telrex methods and materials? The Telrex monobanders
are FB antennas, but how much would the new design weigh? The sheer problem
of supporting such a massive antenna would exacerbate failure modes related
to loading on the boom, clamps, and mounting plates. How much would it cost
to build, install, and support such an antenna if made survivable? At some
point, the older techniques fail to give practical solutions and new
techniques are required.
73, Ward N0AX
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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