The 'best' wire for long antennas is whatever you happen to have
the most of that will support it's own weight. After that, it's more
a matter of what color insulation you think is nice. And after that,
it's whatever you can convince yourself that you can afford. Have
several pieces of different wire size/type? If they will support
their weight, splice the @#$ things! Paint it all pink. Pink works
very well for antennas.
- 'Doc