Owen Duffy wrote:
"JERD" wrote in
:


I am getting back to the HF bands after some 20 years 'rest'. What is
the best type of wire to use for long wire antennas? The wire will be
under some tension to keep it above some local trees!



You might find the article 'Sufficient sag for wire antenna spans for
wind survival' at http://www.vk1od.net/rigging/sag.htm of interest. You
might wonder why annealed copper in almost any form (enamelled, or PVC
insulated, especially PVC insulated) is so popular.

I endorse Roy's support for Copperweld, but you will not find it readily
available in Oz. There are a few suppliers of HDC (ATN and Discount
Cables come to mind). Stainless steel (2mm dia) is used in some of the
commercial antennas (eg Bushcomm), but you need to consider whether the
additional loss is an issue for the specific antenna.

BTW, MIG wire (copper plated steel wire) is not Copperweld, Copperweld
has a substantial copper thickness (eg 30%, depending on the grade) which
is chosen to be at least several skin depths in thickess so that the RF
resistance is similar to copper, but the strength comes largely from the
copper core.

I think you mean the strength comes from the steel core?

FWIW, when they say 30%, that means that the wire has 30% of the
conductivity of the same diameter copper wire, not that it is 30%
copper. You have to look in the mfrs tables to see what the cladding
thickness is.


Odd that there aren't suppliers in Australia.. Maybe because there isn't
an existing telegraph/telephone cable infrastructure in rural areas? In
the U.S., there were and still are millions of miles of the stuff
installed before carrier telephony, coax, optical fibers, etc became
common. And, it's still used for MV power distribution, much of which
is still above ground.