"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. Hams promoting 0.8mm MIG wire (as they do here) are on the
wrong track, it is a grossly inferior product, you are much better off
with galvanised fence wire than MIG wire.

Speaking of which, heavy galvanised steel fence wire (say 1.6mm for
shorter spans) is not all that poor, but beware of newer fence wires
which have thinner zinc, or worse the polymer coated wires with have an
extremely thin layer of ZAl covered by the polymer coating. Though any of
these are going to be better than rusty MIG wire.

Owen