Roy, W7EL wrote:
"Some stainless steels are ferromagnetic, with a permability I`d guess
at 100 or more. That reduces the skin depth, and therefore increases the
RF resistance by a factor of 10."

Being ferromagnetic does not disqualify an antenna material. Most CB
whips are stainless steel. They aren`t too lossy because they are only
about 1/4-wave at 27 MHz and must be large enough in diameter to be
durable. In the range of 0.55 MHz to 1.7 MHz, most transmission is from
ordinary non-stainless steel towers. The only coating on many of these
is paint. The cross-section to length ratio is economically small, but I
doubt the loss added by using nonplated steel could be measured.

Best regards, Richard Harrison, KB5WZI