"InfRes" wrote in message
...
Hi,

I've noticed most homebuilt amateur antennas use tubing and usually
copper,
whereas commercial antennas typically use round bar, either steel or
Aluminum.

I understand the advantages of the materials in terms of electrical
conductivity and weather resistance,
however I dont understand the pro's and cons of using tube vs round
bar? Can you point me to
a book that may discuss this?

Have studies been done re the effect of a layer of oxidation on the
performance of the antenna?

Finally, there is plenty of material about designing antennae for a
band, but every little about designing it at a particular impedence,
can you point me to a discussion on this too?

Thanks

Steven



Electrically there is not much differance in using tubing or rods. It is
mainly about the cost, weight and strength.

Copper is used by many at home because you can get it at the local stores
where aluminum is often hard to come by in lots of towns. Also you can
solder to copper where not many can solder or weld aluminum.

The impedance is not usually that much concern, Just design for gain and
f/b ratio and then match whatever impedance you have to the transmission
line you are going to use.