People seem to have a need to sort everything into binary categories --
like good or bad. And you've pointed out the limitations of doing that.

Stainless steel is fairly resistive stuff to begin with, although
resistivity varies widely depending on the alloy. But the RF resistivity
rises dramatically if the material is magnetic. Some stainless alloys
are magnetic and some aren't. The RF resistivity is proportional to the
square root of the permeability (because of its effect on skin depth),
so a magnetic stainless can easily have ten times the resistivity of a
non-magnetic alloy.

But even a magnetic stainless alloy isn't necessarily "bad". There are
plenty of cases where even that much resistivity is still insignificant,
and won't cause noticeable loss. In particular, if the conductor
diameter is relatively large, or its length is short (in absolute terms,
not in terms of wavelength), the loss will usually be small. This
describes just about all VHF and UHF applications. I wouldn't use small
stainless wire for an 80 meter dipole (unless I wanted to trade a bit of
efficiency for increased bandwidth, which might actually be a good
trade), and certainly not for an electrically small transmitting loop,
where the current is extremely high. But it's definitely a suitable
material for a lot of antenna applications. And it's certainly durable,
as you've noted.

If you were to trade your stainless antenna for one that isn't, there'd
be no perceptible difference in performance, and the replacement
wouldn't last as long. I wouldn't change it either.

Roy Lewallen, W7EL

KA9CAR wrote:
. . .
Stainless steel is a terrible thing to use for an antenna due to eddy
current losses and lower condutivity than copper. The only way to avoid
that is with an aluminum, or copper and fiberglass antenna.

Mine is stainless steel and has been up several years. I have no intention
of changing it!

KA9CAR

- - - - on the other hand a magnetic stainless steel tube or radio mast,
used as an antenna element, may/will have an RF resistance loss smaller than
a 14-gauge copper wire which otherwise would have been adequate.

Why? Simply by virtue of its far greater diameter and surface area.

You have the advantages of self-supporting structural ability, durability,
AND lower RF loss, AND wider bandwidth.

A deprived quantitaive familiarity, engineering dependence on popular,
plagiarised "Bibles" are dangerous things.

What was it the later, oft-quoted, Lord Kelvin said ?