Hmmm...My book says aluminum's resistivity is about 2.6 microohm-cm,
and copper's is 1.7, only a 1.5:1 ratio--though it may not be quite
that good for commonly used aluminum alloys. OTOH, copper also
suffers from being alloyed. But in any event, it's good to keep in
mind that the RF resistance ratio for non-magnetic materials goes as
the square root of the bulk resistivity ratio, because higher
resistivity materials have larger skin depth. So a 2:1 ratio at DC
ends up being only 1.41:1 at RF, and 1.5:1 at DC is only a bit over
1.2:1 at RF.

Since both copper and aluminum have good conductivity, it's just not
worth sweating in practically all cases, unless the antenna is very
short (and thus has very low feedpoint radiation resistance).

Actually, what I thought Gary might be getting at is the protection
from corrosion that gold might offer, as compared with bare copper.
I'd say that it IS worth worrying about protecting your antenna from
corrosion. Maybe you just have to think about it long enough to
understand that you are lucky to live in a place where corrosion isn't
a problem, or maybe you live next to the ocean where salt spray will
get the best of almost anything metallic. But like Roy says, gold
over nickel is probably a bad idea. Unplated stainless steel antenna
wire is probably a bad idea. Painted copper pipe, or anodized
aluminum tubing, will probably work well for a long time.

Cheers,
Tom


"H. Adam Stevens, NQ5H" wrote in message ...
Hi Roy;
It's worse than that: Copper will diffuse throught the gold and pile up on
the surface.
I showed that with an Auger microprobe at Motorola decades ago.
So to go to a gold surface, nickel is mandatory, then a thick gold coating;
Too expensive!
It's not like the switch from aluminum to copper, which is a 2x resistivity
improvement.
You just can't beat plain old copper.
73
H.
NQ5H