wrote:
It seems that my location boasts 60 to 110 mph winds on a regular
basis. I had put up a 1/4 wavelength 20m vertical with 1/8 wavelength
radials elevated at 7 feet, with rope guys... and the wind blew it
apart like so much tin foil!

I use 2x(2"x4"s) fastened together for a 4"x4" support and 1/4WL
wire radials as ground-plane/guy-wires. The vertical section is
assembled from 6' telescoping aluminum sections following the beam
element design guidelines in the ARRL Antenna Book. The top 8.5'
is a stainless steel CB whip. It has withstood wind gusts of about
100 mph. As others have said, copper is a poor choice for a 20m
vertical.
--
73, Cecil http://www.qsl.net/w5dxp

Actually, pure aluminium is even softer and far more ductile than
copper and is useless as a construction material.

But some grades of copper/aluminium alloy, known in the UK as
Duraluminum or just Dural, have properties approaching carbon steel
and are corrosion resistant. Light in weight. Easily machined and
extruded. Maintain a good appearance. High electrical conductivity.
More expensive than steel.

They are used, for example, for ladders and scaffold poles. When used
for tubular rigid dipoles and antenna masts they collapse under high
winds only because the wall thickness is too thin. Commonly used for
radio chassis and sheet metal roofs.

But NOT pure aluminium, just a few percent of copper.
----
Reg.


"Cecil Moore" wrote in message
. com...
wrote:
It seems that my location boasts 60 to 110 mph winds on a regular
basis. I had put up a 1/4 wavelength 20m vertical with 1/8
wavelength
radials elevated at 7 feet, with rope guys... and the wind blew it
apart like so much tin foil!

I use 2x(2"x4"s) fastened together for a 4"x4" support and 1/4WL
wire radials as ground-plane/guy-wires. The vertical section is
assembled from 6' telescoping aluminum sections following the beam
element design guidelines in the ARRL Antenna Book. The top 8.5'
is a stainless steel CB whip. It has withstood wind gusts of about
100 mph. As others have said, copper is a poor choice for a 20m
vertical.
--
73, Cecil http://www.qsl.net/w5dxp

Reg Edwards wrote:
But NOT pure aluminium, just a few percent of copper.

Next time I'll have to remember what a purist you are,
Reg. I'll specify Aluminum 6063-T832 or some such.
--
73, Cecil http://www.qsl.net/w5dxp