In article ,
Pilgrim wrote:

Tin has a much lower conductivity than copper, and as RF travels on
the surface of a conductor, it would attenuate RF and high frequency AC

Is that why most, but not all, teflon insulated wire was silver plated?

My understanding is that the Teflon-insulated wire uses silverplating
for a couple of reasons, related to the high melting point of Teflon
(and thus the high temperatures to which the wire is exposed when the
Teflon is melt-extruded onto the conductors).

The old-standard tin/lead tinning material can't be used in this
high-temperature environment, as it would be melted by the heat of the
Teflon extrusion, and would fuse a stranded-conductor wire into an
inflexible single strand.

Not tinning or plating the wire would leave the surface of the copper
exposed to high temperatures during the extrusion... I suspect that it
would oxidize (if there's any free oxygen in that environment... dunno
about that) or might react with the polymer. Even if it didn't react
at that time, oxygen would infiltrate the wire at the cut end (albeit
slowly) and the last few inches of the wire might end up with a
significant amount of copper oxide on the conducter surface.

Silver-plating protects the copper from oxidation (I gather that
silver oxide is somewhat easier for fluxes to deal with?) and the
silver doesn't melt at the Teflon extrusion temperature.

I don't believe that the silver plating is thick enough to give the
wire a significant conductivity advantage over pure copper, even at RF
frequencies.

--
Dave Platt AE6EO
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