On Apr 17, 8:41*am, Pilgrim wrote:
In article ,
*"Steve Terry" wrote:

"Sandi" wrote in message
...
snip
Does the tinning-coating replace where copper would have been in
the overall wire and tinning is of higher reistence?
Is flexibility affected?

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

Steve Terry

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

I think the reason for silver-plated teflon wiring is mostly milspec
compliance (and the follow-ons that include the mispecs.) The real
question is, why is it in the milspec? Certainly WWII and Korea
influenced milspecs a lot to focus on fungus-proofing, and Teflon had
some advantages back then when the other insulators were not so fungus
resistant. At the same time, other insulating materials can turn
copper or even tin-plated copper inside the insulation black with a
kinda sooty residue (common on Romex from the 50's-70's for example).
It seems to me that silver-plated teflon was a kind of knee jerk
reaction to these two issues, a belt-and-suspenders-cost-is-no-object
approach to a pretty mundane but really fundamental issue.

It's a real joy to work on ex-military equipment with Teflon cable
assemblies. Compare it to other consumer or less-speced industrial
stuff from the same era with PVC-type insulation, where you flex the
cable a little bit and the insulation cracks and falls off leaving
bare wires.

Tim N3QE